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Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Water Dynamics in Salt Solutions Studied with Ultrafast Two-Dimensional Infrared (2D IR)  

E-Print Network [OSTI]

Water Dynamics in Salt Solutions Studied with Ultrafast Two-Dimensional Infrared (2D IR RECEIVED ON FEBRUARY 3, 2009 C O N S P E C T U S Water is ubiquitous in nature, but it exists as pure water infrequently. From the ocean to biology, water molecules interact with a wide variety of dissolved species

Fayer, Michael D.

2

Thompson/Ocean 420/Winter 2004 2D waves 1 Two-dimensional wave propagation  

E-Print Network [OSTI]

Thompson/Ocean 420/Winter 2004 2D waves 1 Two-dimensional wave propagation So far we have talked about wave propagation in one-dimension. For two or three spatial dimensions, we vectorize our ideas propagation. For surface waves, there is no vertical propagation, and we are only concerned with the two

Thompson, LuAnne

3

A new model for two-dimensional numerical simulation of pseudo-2D gas-solids fluidized beds  

SciTech Connect (OSTI)

Pseudo-two dimensional (pseudo-2D) fluidized beds, for which the thickness of the system is much smaller than the other two dimensions, is widely used to perform fundamental studies on bubble behavior, solids mixing, or clustering phenomenon in different gas-solids fluidization systems. The abundant data from such experimental systems are very useful for numerical model development and validation. However, it has been reported that two-dimensional (2D) computational fluid dynamic (CFD) simulations of pseudo-2D gas-solids fluidized beds usually predict poor quantitative agreement with the experimental data, especially for the solids velocity field. In this paper, a new model is proposed to improve the 2D numerical simulations of pseudo-2D gas-solids fluidized beds by properly accounting for the frictional effect of the front and back walls. Two previously reported pseudo-2D experimental systems were simulated with this model. Compared to the traditional 2D simulations, significant improvements in the numerical predictions have been observed and the predicted results are in better agreement with the available experimental data.

Li, Tingwen; Zhang, Yongmin

2013-10-11T23:59:59.000Z

4

Development of models for the two-dimensional, two-fluid code for sodium boiling NATOF-2D  

E-Print Network [OSTI]

Several features were incorporated into NATOF-2D, a twodimensional, two fluid code developed at M.I.T. for the purpose of analysis of sodium boiling transients under LMFBR conditions. They include improved interfacial mass, ...

Zielinski, R. G.

1981-01-01T23:59:59.000Z

5

Study of reflection and transport in the microwave photo-excited GaAs/AlGaAs two dimensional electron system  

SciTech Connect (OSTI)

We present the results of a concurrent experimental study of microwave reflection and transport in the GaAs/AlGaAs two dimensional electron gas system and correlate observed features in the reflection with the observed transport features. The experimental results are compared with expectations based on theory.

Ye, Tianyu; Mani, Ramesh G. [Department of Physics and Astronomy, Georgia State University, Atlanta GA 30303 (United States); Wegscheider, Werner [Laboratorium für Festkörperphysik, ETH Zürich, 8093 Zürich (Switzerland)

2013-12-04T23:59:59.000Z

6

JAC2D: A two-dimensional finite element computer program for the nonlinear quasi-static response of solids with the conjugate gradient method; Yucca Mountain Site Characterization Project  

SciTech Connect (OSTI)

JAC2D is a two-dimensional finite element program designed to solve quasi-static nonlinear mechanics problems. A set of continuum equations describes the nonlinear mechanics involving large rotation and strain. A nonlinear conjugate gradient method is used to solve the equations. The method is implemented in a two-dimensional setting with various methods for accelerating convergence. Sliding interface logic is also implemented. A four-node Lagrangian uniform strain element is used with hourglass stiffness to control the zero-energy modes. This report documents the elastic and isothermal elastic/plastic material model. Other material models, documented elsewhere, are also available. The program is vectorized for efficient performance on Cray computers. Sample problems described are the bending of a thin beam, the rotation of a unit cube, and the pressurization and thermal loading of a hollow sphere.

Biffle, J.H.; Blanford, M.L.

1994-05-01T23:59:59.000Z

7

Seismic isolation of two dimensional periodic foundations  

SciTech Connect (OSTI)

Phononic crystal is now used to control acoustic waves. When the crystal goes to a larger scale, it is called periodic structure. The band gaps of the periodic structure can be reduced to range from 0.5?Hz to 50?Hz. Therefore, the periodic structure has potential applications in seismic wave reflection. In civil engineering, the periodic structure can be served as the foundation of upper structure. This type of foundation consisting of periodic structure is called periodic foundation. When the frequency of seismic waves falls into the band gaps of the periodic foundation, the seismic wave can be blocked. Field experiments of a scaled two dimensional (2D) periodic foundation with an upper structure were conducted to verify the band gap effects. Test results showed the 2D periodic foundation can effectively reduce the response of the upper structure for excitations with frequencies within the frequency band gaps. When the experimental and the finite element analysis results are compared, they agree well with each other, indicating that 2D periodic foundation is a feasible way of reducing seismic vibrations.

Yan, Y.; Mo, Y. L., E-mail: yilungmo@central.uh.edu [University of Houston, Houston, Texas 77004 (United States); Laskar, A. [Indian Institute of Technology Bombay, Powai, Mumbai (India); Cheng, Z.; Shi, Z. [Beijing Jiaotong University, Beijing (China); Menq, F. [University of Texas, Austin, Texas 78712 (United States); Tang, Y. [Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2014-07-28T23:59:59.000Z

8

Two-dimensional Photonic Crystals Fabricated by Nanoimprint Lithography  

E-Print Network [OSTI]

We report on the process parameters of nanoimprint lithography (NIL) for the fabrication of two-dimensional (2-D) photonic crystals. The nickel mould with 2-D photonic crystal patterns covering the area up to 20mm² is ...

Chen, A.

9

Coherent Atom Optics With Fast Metastable Beams: Metastable Helium Diffraction By 1D and 2D Magnetized Reflection Gratings  

SciTech Connect (OSTI)

1D and 2D reflection gratings (Permalloy stripes or dots deposited on silicon), immersed in an external homogeneous static magnetic field, are used to study 1D and 2D diffraction of fast metastable helium atoms He* (23S1). Both the grazing incidence used here and the repulsive potential (for sub-level m = -1) generated by the magnetisation reduce the quenching effect. This periodically structured potential is responsible for the diffraction in the incidence plane as well as for the diffraction in the perpendicular plane.

Grucker, J.; Baudon, J.; Karam, J.-C.; Perales, F.; Ducloy, M. [Laboratoire de Physique des Lasers, UMR-CNRS 7538, Universite Paris 13, 99, Avenue J.B. Clement, 93430-Villetaneuse (France); Bocvarski, V. [Institute of Physics, Pregrevica 118, 11080 - Belgrade-Zemun (Serbia and Montenegro)

2007-04-23T23:59:59.000Z

10

A compact chaotic laser device with a two-dimensional external cavity structure  

SciTech Connect (OSTI)

We propose a compact chaotic laser device, which consists of a semiconductor laser and a two-dimensional (2D) external cavity for delayed optical feedback. The overall size of the device is within 230??m?×?1?mm. A long time delay sufficient for chaos generation can be achieved with the small area by the multiple reflections at the 2D cavity boundary, and the feedback strength is controlled by the injection current to the external cavity. We experimentally demonstrate that a variety of output properties, including chaotic output, can be selectively generated by controlling the injection current to the external cavity.

Sunada, Satoshi, E-mail: sunada@se.kanazawa-u.ac.jp; Adachi, Masaaki [Faculty of Mechanical Engineering, Institute of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192 (Japan); Fukushima, Takehiro [Department of Information and Communication Engineering, Okayama Prefectural University, 111 Kuboki, Soja, Okayama 719-1197 (Japan); Shinohara, Susumu; Arai, Kenichi [NTT Communication Science Laboratories, NTT Corporation, 2-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0237 (Japan); Harayama, Takahisa [NTT Communication Science Laboratories, NTT Corporation, 2-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0237 (Japan); Department of Mechanical Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan)

2014-06-16T23:59:59.000Z

11

Ultra-Shallow Imaging Using 2D & 3D Seismic Reflection Methods  

E-Print Network [OSTI]

The research presented in this dissertation focuses on the survey design, acquisition, processing, and interpretation of ultra-shallow seismic reflection (USR) data in two and three dimensions. The application of 3D USR methods to image multiple...

Sloan, Steven D.

2008-01-01T23:59:59.000Z

12

Introduction Two-dimensional (2D) methods for  

E-Print Network [OSTI]

need 3D structures in order to implement complex designs. These re- quirements have stimulated or printing. PDMS is inexpen- sive, homogeneous, optically transparent, nontoxic, and commercially available. The flexibility of the PDMS replicas also al- lows patterning by microcontact printing or micromolding

Prentiss, Mara

13

Two-dimensional fourier transform spectrometer  

DOE Patents [OSTI]

The present invention relates to a system and methods for acquiring two-dimensional Fourier transform (2D FT) spectra. Overlap of a collinear pulse pair and probe induce a molecular response which is collected by spectral dispersion of the signal modulated probe beam. Simultaneous collection of the molecular response, pulse timing and characteristics permit real time phasing and rapid acquisition of spectra. Full spectra are acquired as a function of pulse pair timings and numerically transformed to achieve the full frequency-frequency spectrum. This method demonstrates the ability to acquire information on molecular dynamics, couplings and structure in a simple apparatus. Multi-dimensional methods can be used for diagnostic and analytical measurements in the biological, biomedical, and chemical fields.

DeFlores, Lauren; Tokmakoff, Andrei

2013-09-03T23:59:59.000Z

14

Two-dimensional 1,3,5-Tris(4-carboxyphenyl)benzene self-assembly at  

E-Print Network [OSTI]

Two-dimensional 1,3,5-Tris(4-carboxyphenyl)benzene self-assembly at the 1-phenyloctane and published work see http://pubs.rsc.org/en/journals/journalissues/tc. Two-dimensional (2D) self-assembly storage, selective ion exchange, high den- sity data storage, etc. Molecular self-assembly offers unique

Paris-Sud XI, Université de

15

The two dimensional Cerenkov radiation  

E-Print Network [OSTI]

We derive the power spectrum of photons generated by charged particle moving in parallel direction to the graphene-like structure with index of refraction n. While the graphene sheet is conductive, some graphene-like structures, for instance graphene with implanted ions, or, also 2D-glasses, are dielectric media, and it means that it enables the experimental realization of the Cerenkov radiation. We calculate it from the viewpoint of the Schwinger theory of sources.

Miroslav Pardy

2012-09-25T23:59:59.000Z

16

A nanoscale probe of the quasiparticle band structure for two dimensional electron systems  

E-Print Network [OSTI]

The advent of a broad class of two-dimensional (2D) electronic materials has provided avenues to create and study designer electronic quantum phases. The coexistence of superconductivity, magnetism, density waves, and other ...

Soumyanarayanan, Anjan

2013-01-01T23:59:59.000Z

17

A two-dimensional volatility basis set – Part 2: Diagnostics of organic-aerosol evolution  

E-Print Network [OSTI]

We discuss the use of a two-dimensional volatility-oxidation space (2-D-VBS) to describe organic-aerosol chemical evolution. The space is built around two coordinates, volatility and the degree of oxidation, both of which ...

Donahue, N. M.

18

Two-dimensional photonic crystals as selective emitters for thermophotovoltaic power conversion applications  

E-Print Network [OSTI]

This research investigates the use of two-dimensional (2D) photonic crystals (PhC) as selective emitters and means of achieving higher efficiencies in combustion-driven thermophotovoltaic (TPV) systems intended as auxiliary ...

Jovanovic, Natalija Zorana

2005-01-01T23:59:59.000Z

19

Multi-mode two-dimensional infrared spectroscopy of peptides and proteins  

E-Print Network [OSTI]

In this thesis, a methodology for understanding structural stability of proteins through multi-mode two-dimensional infrared (2D IR) spectroscopy is developed. The experimental framework for generation of broadband infrared ...

DeFlores, Lauren P

2008-01-01T23:59:59.000Z

20

Electron localization function for two-dimensional systems E. Rsnen,* A. Castro, and E. K. U. Gross  

E-Print Network [OSTI]

Electron localization function for two-dimensional systems E. Räsänen,* A. Castro, and E. K. U The concept of the electron localization function ELF is extended to two-dimensional 2D electron systems. We systems focusing on semiconductor quantum dots that effectively correspond to a confined 2D electron gas

Gross, E.K.U.

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Two-dimensional interpreter for field-reversed configurations  

SciTech Connect (OSTI)

An interpretive method is developed for extracting details of the fully two-dimensional (2D) “internal” structure of field-reversed configurations (FRC) from common diagnostics. The challenge is that only external and “gross” diagnostics are routinely available in FRC experiments. Inferring such critical quantities as the poloidal flux and the particle inventory has commonly relied on a theoretical construct based on a quasi-one-dimensional approximation. Such inferences sometimes differ markedly from the more accurate, fully 2D reconstructions of equilibria. An interpreter based on a fully 2D reconstruction is needed to enable realistic within-the-shot tracking of evolving equilibrium properties. Presented here is a flexible equilibrium reconstruction with which an extensive data base of equilibria was constructed. An automated interpreter then uses this data base as a look-up table to extract evolving properties. This tool is applied to data from the FRC facility at Tri Alpha Energy. It yields surprising results at several points, such as the inferences that the local ? (plasma pressure/external magnetic pressure) of the plasma climbs well above unity and the poloidal flux loss time is somewhat longer than previously thought, both of which arise from full two-dimensionality of FRCs.

Steinhauer, Loren, E-mail: lstein@uw.edu [Tri Alpha Energy, Rancho Santa Margarita, California 92688 (United States)

2014-08-15T23:59:59.000Z

22

Two-dimensional materials for electronic applications  

E-Print Network [OSTI]

The successful isolation of graphene in 2004 has attracted great interest to search for potential applications of this unique material and other members of the two-dimensional materials family in electronics, optoelectronics ...

Wang, Han, Ph. D. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

23

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 1, 2002 53 Two-Dimensional FDTD Model of Antipodal ELF  

E-Print Network [OSTI]

and the Schumann resonance. II. FDTD GRID To simplify computations, we seek to map the complete spherical surface conditions are used in conjunction with a variable-cell two-dimensional TM FDTD grid, which wraps around-domain (FDTD) method [4]. He used a two-dimensional (2-D) cylindrical-coordinate FDTD grid to investigate

Simpson, Jamesina J.

24

Movement behaviour of traditionally managed cattle in the Eastern Province of Zambia: investigations using two-dimensional motion sensors   

E-Print Network [OSTI]

Two-dimensional (2-D) motion sensors are activity motion sensors that use electronic accelerometers to record the lying, standing and walking behaviour of animals. They were used in this study with the aim of monitoring and quantifying the movement...

Lubaba, Caesar Himbayi

2011-06-27T23:59:59.000Z

25

Holographic and time-resolving ability of pulse-pair two-dimensional velocity interferometry  

SciTech Connect (OSTI)

Previous velocity interferometers used at research laboratories for shock physics experiments measured target motion at a point or many points on a line on the target. Recently, a two-dimensional (2d) version (2d-velocity interferometer system for any reflector) has been demonstrated using a pair of ultrashort (3 ps) pulses for illumination, separated by 268 ps. We have discovered new abilities for this instrument, by treating the complex output image as a hologram. For data taken in an out of focus configuration, we can Fourier process to bring narrow features such as cracks into sharp focus, which are otherwise completely blurred. This solves a practical problem when using high numerical aperture optics having narrow depth of field to observe moving surface features such as cracks. Furthermore, theory predicts that the target appearance (position and reflectivity) at two separate moments in time are recorded by the main and conjugate images of the same hologram, and are partially separable during analysis for narrow features. Hence, for the cracks we bring into refocus, we can make a two-frame movie with a subnanosecond frame period. Longer and shorter frame periods are possible with different interferometer delays. Since the megapixel optical detectors we use have superior spatial resolution over electronic beam based framing cameras, this technology could be of great use in studying microscopic three-dimensional-behavior of targets at ultrafast times scales. Demonstrations on shocked silicon are shown.

Erskine, David J., E-mail: erskine1@llnl.gov; Smith, R. F.; Celliers, P. M.; Collins, G. W. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Bolme, C. A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ali, S. J. [Department of Chemistry, University of California, Berkeley, California 94720 (United States)

2014-06-15T23:59:59.000Z

26

Quasi-two-dimensional Dirac fermions and quantum magnetoresistance in LaAgBi2  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

We report quasi-two-dimensional (2D) Dirac fermions and quantum magnetoresistance in LaAgBi2. The band structure shows several narrow bands with nearly linear energy dispersion and Dirac-cone-like points at the Fermi level. The quantum oscillation experiments revealed one quasi-two-dimensional Fermi pocket and another complex pocket with a small cyclotron resonant mass. The in-plane transverse magnetoresistance exhibits a crossover at a critical field B? from semiclassical weak-field B2 dependence to the high-field unsaturated linear magnetoresistance which is attributed to the quantum limit of the Dirac fermions. Our results suggest the existence of quasi-2D Dirac fermions in rare-earth-based layered compounds with two-dimensional double-sized Bi square nets, similar to (Ca,Sr)MnBi2, irrespective of magnetic order.

Wang, Kefeng; Graf, D.; Petrovic, C.

2013-06-01T23:59:59.000Z

27

Localization of topological changes in Couette and Poiseuille flows of two-dimensional foams  

E-Print Network [OSTI]

-dimensional (2D) foams, such as can be made by squeezing a foam between parallel glass plates until it consistsLocalization of topological changes in Couette and Poiseuille flows of two-dimensional foams S. Quasistatic simulations show that the topological changes or plastic events that occur when an aqueous foam

Cox, Simon

28

Statistical Mechanics of Two-dimensional Foams  

E-Print Network [OSTI]

The methods of statistical mechanics are applied to two-dimensional foams under macroscopic agitation. A new variable -- the total cell curvature -- is introduced, which plays the role of energy in conventional statistical thermodynamics. The probability distribution of the number of sides for a cell of given area is derived. This expression allows to correlate the distribution of sides ("topological disorder") to the distribution of sizes ("geometrical disorder") in a foam. The model predictions agree well with available experimental data.

Marc Durand

2010-09-07T23:59:59.000Z

29

Two-Dimensional Superconducting Fluctuations in Stripe-Ordered La1:875Ba0:125CuO4 Q. Li, M. Hucker, G. D. Gu, A. M. Tsvelik, and J. M. Tranquada  

E-Print Network [OSTI]

Two-Dimensional Superconducting Fluctuations in Stripe-Ordered La1:875Ba0:125CuO4 Q. Li, M. Hu of two-dimensional (2D) fluctuating superconductivity, which eventually reaches a 2D superconductingÿxBaxCuO4 frustrates three-dimensional superconducting phase order, but is fully compatible with 2D

30

Two-dimensional stimulated resonance Raman spectroscopy of molecules with broadband x-ray pulses  

SciTech Connect (OSTI)

Expressions for the two-dimensional stimulated x-ray Raman spectroscopy (2D-SXRS) signal obtained using attosecond x-ray pulses are derived. The 1D- and 2D-SXRS signals are calculated for trans-N-methyl acetamide (NMA) with broad bandwidth (181 as, 14.2 eV FWHM) pulses tuned to the oxygen and nitrogen K-edges. Crosspeaks in 2D signals reveal electronic Franck-Condon overlaps between valence orbitals and relaxed orbitals in the presence of the core-hole.

Biggs, Jason D.; Zhang Yu; Healion, Daniel; Mukamel, Shaul [Department of Chemistry, University of California, Irvine, California 92697-2025 (United States)

2012-05-07T23:59:59.000Z

31

Two dimensional Sen connections in general relativity  

E-Print Network [OSTI]

The two dimensional version of the Sen connection for spinors and tensors on spacelike 2-surfaces is constructed. A complex metric $\\gamma_{AB}$ on the spin spaces is found which characterizes both the algebraic and extrinsic geometrical properties of the 2-surface $\\$ $. The curvature of the two dimensional Sen operator $\\Delta_e$ is the pull back to $\\$ $ of the anti-self-dual part of the spacetime curvature while its `torsion' is a boost gauge invariant expression of the extrinsic curvatures of $\\$ $. The difference of the 2 dimensional Sen and the induced spin connections is the anti-self-dual part of the `torsion'. The irreducible parts of $\\Delta_e$ are shown to be the familiar 2-surface twistor and the Weyl--Sen--Witten operators. Two Sen--Witten type identities are derived, the first is an identity between the 2 dimensional twistor and the Weyl--Sen--Witten operators and the integrand of Penrose's charge integral, while the second contains the `torsion' as well. For spinor fields satisfying the 2-surface twistor equation the first reduces to Tod's formula for the kinematical twistor.

L. B. Szabados

1994-02-01T23:59:59.000Z

32

Theory and application of the RAZOR two-dimensional continuous energy lattice physics code  

SciTech Connect (OSTI)

The theory and application of the RAZOR two-dimensional, continuous energy lattice physics code are discussed. RAZOR solves the continuous energy neutron transport equation in one- and two-dimensional geometries, and calculates equivalent few-group diffusion theory constants that rigorously account for spatial and spectral self-shielding effects. A dual energy resolution slowing down algorithm is used to reduce computer memory and disk storage requirements for the slowing down calculation. Results are presented for a 2D BWR pin cell depletion benchmark problem.

Zerkle, M.L.; Abu-Shumays, I.K.; Ott, M.W.; Winwood, J.P.

1997-04-01T23:59:59.000Z

33

Graphene forms template for two-dimensional hybrid materials...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Graphene forms template for two-dimensional hybrid materials January 17, 2014 Researchers have developed a new technique for forming a two-dimensional, single-atom sheet of two...

34

Two-dimensional Ricci flow as a stochastic process  

E-Print Network [OSTI]

We prove that, for a two-dimensional Riemannian manifold, the Ricci flow is obtained by a Wiener process.

Marco Frasca

2009-01-29T23:59:59.000Z

35

Localized electrons in the metallic phase of the two-dimensional electron system at ,,Al,Ga...As-GaAs heterojunctions  

E-Print Network [OSTI]

Localized electrons in the metallic phase of the two-dimensional electron system at ,,Al, United Kingdom Received 29 October 1996 Using the effect of electron focusing we measure the Fermi wave vector of the delocalized electrons in a two-dimensional 2D electron system. After obtaining the total

Ludwig-Maximilians-Universität, München

36

Onsager-Kraichnan Condensation in Decaying Two-Dimensional Quantum Turbulence  

E-Print Network [OSTI]

A negative-temperature statistical equilibrium state of two-dimensional quantum vortices can exhibit clustering of same-circulation vortices and a macroscopic accumulation of kinetic energy at the system length scale, which we term an Onsager-Kraichnan condensate (OKC). We develop a method for microcanonical sampling of equilibrium vortex configurations in the homogeneous 2D Gross-Pitaevskii theory. Varying the system energy at fixed vortex number, we characterize the possible states of vortex matter in a bulk superfluid, from the vortex-dipole gas at positive temperature, to negative-temperature OKC states exhibiting macroscopic vortex clustering and kinetic energy condensation. Dynamical simulations reveal that negative-temperature OKC states emerge as the end states of decaying two-dimensional quantum turbulence. Our work provides the first realization of Onsager's point-vortex model, and its negative temperature states, in a microscopic theory of a 2D superfluid.

Billam, Thomas P; Anderson, Brian P; Bradley, Ashton S

2013-01-01T23:59:59.000Z

37

Dynamics of two-dimensional dipole systems  

SciTech Connect (OSTI)

Using a combined analytical/molecular dynamics approach, we study the current fluctuation spectra and longitudinal and transverse collective mode dispersions of the classical two-dimensional (point) dipole system (2DDS) characterized by the {phi}{sub D}(r)={mu}{sup 2}/r{sup 3} repulsive interaction potential; {mu} is the electric dipole strength. The interest in the 2DDS is twofold. First, the quasi-long-range 1/r{sup 3} interaction makes the system a unique classical many-body system, with a remarkable collective mode behavior. Second, the system may be a good model for a closely spaced semiconductor electron-hole bilayer, a system that is in the forefront of current experimental interest. The longitudinal collective excitations, which are of primary interest for the liquid phase, are acoustic at long wavelengths. At higher wave numbers and for sufficiently high coupling strength, we observe the formation of a deep minimum in the dispersion curve preceded by a sharp maximum; this is identical to what has been observed in the dispersion of the zero-temperature bosonic dipole system, which in turn emulates so-called roton-maxon excitation spectrum of the superfluid {sup 4}He. The analysis we present gives an insight into the emergence of this apparently universal structure, governed by strong correlations. We study both the liquid and the crystalline solid state. We also observe the excitation of combination frequencies, resembling the roton-roton, roton-maxon, etc. structures in {sup 4}He.

Golden, Kenneth I.; Kalman, Gabor J.; Hartmann, Peter; Donko, Zoltan [Department of Mathematics and Statistics, Department of Physics, University of Vermont, Burlington, Vermont 05401 (United States); Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467 (United States); Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary and Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467 (United States)

2010-09-15T23:59:59.000Z

38

Broadband optical coupling between microstructured fibers and photonic band gap circuits: Two-dimensional paradigms  

E-Print Network [OSTI]

simple two-dimensional design models. We demonstrate an effective large- bandwidth small-footprint beam platform for integrated optics. Unlike conventional paradigms such as silicon on insulator SOI waveguides that guide light on a chip by total internal reflection index guiding , PBG-based microcircuits can guide

John, Sajeev

39

Unification of BKT and BEC Phase Transitions in a Trapped Two-Dimensional Bose Gas  

E-Print Network [OSTI]

We study the critical point for the emergence of coherence in a harmonically trapped two-dimensional (2d) Bose gas with tuneable interactions. Over a wide range of interaction strengths we find excellent agreement with predictions based on the Berezinskii-Kosterlitz-Thouless (BKT) theory of 2d superfluidity. This allows us to quantitatively show, without any free parameters, that the interaction-driven BKT transition smoothly converges onto the purely statistical Bose-Einstein condensation (BEC) transition in the limit of vanishing interactions.

Fletcher, Richard J; Man, Jay; Navon, Nir; Smith, Robert P; Viebahn, Konrad; Hadzibabic, Zoran

2015-01-01T23:59:59.000Z

40

Two-dimensional electronic spectroscopy based on conventional optics and fast dual chopper data acquisition  

SciTech Connect (OSTI)

We report an improved experimental scheme for two-dimensional electronic spectroscopy (2D-ES) based solely on conventional optical components and fast data acquisition. This is accomplished by working with two choppers synchronized to a 10 kHz repetition rate amplified laser system. We demonstrate how scattering and pump-probe contributions can be removed during 2D measurements and how the pump probe and local oscillator spectra can be generated and saved simultaneously with each population time measurement. As an example the 2D-ES spectra for cresyl violet were obtained. The resulting 2D spectra show a significant oscillating signal during population evolution time which can be assigned to an intramolecular vibrational mode.

Heisler, Ismael A., E-mail: i.heisler@uea.ac.uk; Moca, Roberta; Meech, Stephen R., E-mail: s.meech@uea.ac.uk [School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ (United Kingdom); Camargo, Franco V. A. [School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ (United Kingdom); CAPES Foundation, Ministry of Education of Brazil, Brasília - DF 70040-020 (Brazil)

2014-06-15T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Femtosecond X-ray Diffraction From Two-Dimensional Protein Crystals  

SciTech Connect (OSTI)

Here we present femtosecond x-ray diffraction patterns from two-dimensional (2-D) protein crystals using an x-ray free electron laser (XFEL). To date it has not been possible to acquire x-ray diffraction from individual 2-D protein crystals due to radiation damage. However, the intense and ultrafast pulses generated by an XFEL permits a new method of collecting diffraction data before the sample is destroyed. Utilizing a diffract-before-destroy methodology at the Linac Coherent Light Source, we observed Bragg diffraction to better than 8.5 Å resolution for two different 2-D protein crystal samples that were maintained at room temperature. These proof-of-principle results show promise for structural analysis of both soluble and membrane proteins arranged as 2-D crystals without requiring cryogenic conditions or the formation of three-dimensional crystals.

Frank, Matthias; Carlson, David B.; Hunter, Mark; Williams, Garth J.; Messerschmidt, Marc; Zatsepin, Nadia A.; Barty, Anton; Benner, Henry; Chu, Kaiqin; Graf, Alexander; Hau-Riege, Stefan; Kirian, Rick; Padeste, Celestino; Pardini, Tommaso; Pedrini, Bill; Segelke, Brent; Seibert, M. M.; Spence , John C.; Tsai, Ching-Ju; Lane, Steve M.; Li, Xiao-Dan; Schertler, Gebhard; Boutet, Sebastien; Coleman, Matthew A.; Evans, James E.

2014-02-28T23:59:59.000Z

42

Two-Dimensional Gas of Massless Dirac Fermions in Graphene  

E-Print Network [OSTI]

Electronic properties of materials are commonly described by quasiparticles that behave as non-relativistic electrons with a finite mass and obey the Schroedinger equation. Here we report a condensed matter system where electron transport is essentially governed by the Dirac equation and charge carriers mimic relativistic particles with zero mass and an effective "speed of light" c* ~10^6m/s. Our studies of graphene - a single atomic layer of carbon - have revealed a variety of unusual phenomena characteristic of two-dimensional (2D) Dirac fermions. In particular, we have observed that a) the integer quantum Hall effect in graphene is anomalous in that it occurs at half-integer filling factors; b) graphene's conductivity never falls below a minimum value corresponding to the conductance quantum e^2/h, even when carrier concentrations tend to zero; c) the cyclotron mass m of massless carriers with energy E in graphene is described by equation E =mc*^2; and d) Shubnikov-de Haas oscillations in graphene exhibit a phase shift of pi due to Berry's phase.

K. S. Novoselov; A. K. Geim; S. V. Morozov; D. Jiang; M. I. Katsnelson; I. V. Grigorieva; S. V. Dubonos; A. A. Firsov

2005-09-13T23:59:59.000Z

43

Two-dimensional polymer synthesis : towards a two-dimensional replicating system for nanostructures  

E-Print Network [OSTI]

The general concept of a replicating monolayer system is introduced as a new method of nanostructure synthesis. One possible implementation of a 2-D replicating system is pursued which uses a diacetylene moiety for ...

Mosley, David W

2005-01-01T23:59:59.000Z

44

Observation of leaky slab modes in an air-bridged semiconductor waveguide with a two-dimensional photonic lattice  

E-Print Network [OSTI]

Observation of leaky slab modes in an air-bridged semiconductor waveguide with a two An air-bridged, 120-nm-thick semiconductor slab with a two-dimensional 2D square array of through holes dramatic effects have been observed in semiconductor microcavity structures in which the physical structure

Young, Jeff

45

Two-dimensional-spatial distribution measurement of electron temperature and plasma density in low temperature plasmas  

SciTech Connect (OSTI)

A real-time measurement method for two-dimensional (2D) spatial distribution of the electron temperature and plasma density was developed. The method is based on the floating harmonic method and the real time measurement is achieved with little plasma perturbation. 2D arrays of the sensors on a 300 mm diameter wafer-shaped printed circuit board with a high speed multiplexer circuit were used. Experiments were performed in an inductive discharge under various external conditions, such as powers, gas pressures, and different gas mixing ratios. The results are consistent with theoretical prediction. Our method can measure the 2D spatial distribution of plasma parameters on a wafer-level in real-time. This method can be applied to plasma diagnostics to improve the plasma uniformity of plasma reactors for plasma processing.

Kim, Young-Cheol [Department of Nanoscale Semiconductor Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Jang, Sung-Ho; Oh, Se-Jin; Lee, Hyo-Chang; Chung, Chin-Wook [Department of Electrical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)

2013-05-15T23:59:59.000Z

46

Terahertz spectroscopy of two-dimensional subwavelength plasmonic structures  

SciTech Connect (OSTI)

The fascinating properties of plasmonic structures have had significant impact on the development of next generation ultracompact photonic and optoelectronic components. We study two-dimensional plasmonic structures functioning at terahertz frequencies. Resonant terahertz response due to surface plasmons and dipole localized surface plasmons were investigated by the state-of-the-art terahertz time domain spectroscopy (THz-TDS) using both transmission and reflection configurations. Extraordinary terahertz transmission was demonstrated through the subwavelength metallic hole arrays made from good conducting metals as well as poor metals. Metallic arrays m!lde from Pb, generally a poor metal, and having optically thin thicknesses less than one-third of a skin depth also contributed in enhanced THz transmission. A direct transition of a surface plasmon resonance from a photonic crystal minimum was observed in a photo-doped semiconductor array. Electrical controls of the surface plasmon resonances by hybridization of the Schottkey diode between the metallic grating and the semiconductor substrate are investigated as a function of the applied reverse bias. In addition, we have demonstrated photo-induced creation and annihilation of surface plasmons with appropriate semiconductors at room temperature. According to the Fano model, the transmission properties are characterized by two essential contributions: resonant excitation of surface plasmons and nonresonant direct transmission. Such plasmonic structures may find fascinating applications in terahertz imaging, biomedical sensing, subwavelength terahertz spectroscopy, tunable filters, and integrated terahertz devices.

Azad, Abul K [Los Alamos National Laboratory; Chen, Houtong [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory; Han, Jiaguang [OSU; Lu, Xinchao [OSU; Zhang, Weili [OSU

2009-01-01T23:59:59.000Z

47

Palladium chloride to palladium metal two-dimensional nucleation and growth phenomena  

SciTech Connect (OSTI)

The reduction of a monolayer of surface-bound Pd(II) to Pd(0) on a palladium substrate reveals two-dimensional nucleation and growth phenomena. Using well-known 2D nucleation-growth theories, this reduction is shown to proceed by an instantaneous nucleation and growth mechanism. However, when a submonolayer of Pd(II) is present, this mechanism fails to account for the experimentally observed high cathodic currents seen at zero time. A model incorporating preexisting Pd(0) cylindrical sites on the partially oxidized Pd(0) surface has been successfully applied to account for the discrepancy between the experimental results and current 2D theories. Using this modified 2D model, values for the mathematical product of cylindrical growth rate and the square root of the nucleation site densities have been determined, and the overpotential dependence of the growth rate has been confirmed and quantified. These 2D nucleation-growth phenomena have practical consequences on the performance of the Pd(II)/Pd(0) system as a faradaic supercapacitor, and probably on the performance of other 2D faradaic supercapacitor systems. In addition, because many electrodes undergo monolayer surface oxidation-reduction reactions in other solvent systems, especially aqueous electrolytes, these 2D nucleation-growth phenomena may play a role in these important surface-modifying redox systems as well.

Long, H.C. de; Carlin, R.T. [Air Force Academy, CO (United States). Frank J. Seiler Research Lab.

1995-08-01T23:59:59.000Z

48

Effective field theory and integrability in two-dimensional Mott transition  

SciTech Connect (OSTI)

Highlights: > Mott transition in 2d lattice fermion model. > 3D integrability out of 2D. > Effective field theory for Mott transition in 2d. > Double Chern-Simons. > d-Density waves. - Abstract: We study the Mott transition in a two-dimensional lattice spinless fermion model with nearest neighbors density-density interactions. By means of a two-dimensional Jordan-Wigner transformation, the model is mapped onto the lattice XXZ spin model, which is shown to possess a quantum group symmetry as a consequence of a recently found solution of the Zamolodchikov tetrahedron equation. A projection (from three to two space-time dimensions) property of the solution is used to identify the symmetry of the model at the Mott critical point as U{sub q}(sl(2)-circumflex)xU{sub q}(sl(2)-circumflex), with deformation parameter q = -1. Based on this result, the low-energy effective field theory for the model is obtained and shown to be a lattice double Chern-Simons theory with coupling constant k = 1 (with the standard normalization). By further employing the effective filed theory methods, we show that the Mott transition that arises is of topological nature, with vortices in an antiferromagnetic array and matter currents characterized by a d-density wave order parameter. We also analyze the behavior of the system upon weak coupling, and conclude that it undergoes a quantum gas-liquid transition which belongs to the Ising universality class.

Bottesi, Federico L. [Facultad de Ingenieria Pontificia Universidad Catolica Argentina, Av. Alicia Moreau de Justo 1500, 1428 Buenos Aires (Argentina); Physics Department, Comision Nacional de Energia Atomica, Av. Libertador 8250, 1429 Buenos Aires (Argentina); Zemba, Guillermo R., E-mail: zemba@tander.cnea.gov.ar [Facultad de Ingenieria Pontificia Universidad Catolica Argentina, Av. Alicia Moreau de Justo 1500, 1428 Buenos Aires (Argentina); Physics Department, Comision Nacional de Energia Atomica, Av. Libertador 8250, 1429 Buenos Aires (Argentina)

2011-08-15T23:59:59.000Z

49

Spin Dynamics in Two-Dimensional Arrays of Quantum Dots with Local Ordering of Nanoclusters  

SciTech Connect (OSTI)

Electron paramagnetic resonance (EPR) is used to probe the spin dynamics in two-dimensional (2D) quantum dot (QD) arrays with local ordering of nanoclusters. A careful examination of EPR line shape, width and g-factor values allow us to attribute this signal to the electrons localized in the strain-induced potential wells in Si in the vicinity of the Ge dots. The strong orientation dependence of EPR line width is defined by changing localization degree of electrons at different magnetic field directions. The theoretical approximation of orientation dependence of EPR line width allows estimating the effective radius of electron localization, as {approx}80 nm.

Zinovieva, A. F.; Dvurechenskii, A. V.; Stepina, N. P.; Nikiforov, A. I.; Lyubin, A. S. [Institute of Semiconductor Physics, 630090 Novosibirsk, pr. Lavrentieva 13 (Russian Federation); Sobolev, N.; Carmo, M. C. [Departamento de Fisica e I3N, Universidade de Aveiro, Aveiro (Portugal)

2011-12-23T23:59:59.000Z

50

Optical properties of two-dimensional transition metal dichalcogenides  

E-Print Network [OSTI]

The re-discovery of the atomically thin transition metal dichalcogenides (TMDs), which are mostly semiconductors with a wide range of band gaps, has diversified the family of two-dimensional materials and boosted the ...

Lin, Yuxuan, S.M. Massachusetts Institute of Technology

2014-01-01T23:59:59.000Z

51

Healing of defects in a two-dimensional granular crystal  

E-Print Network [OSTI]

Using a macroscopic analog for a two dimensional hexagonal crystal, we perform an experimental investigation of the self-healing properties of circular grain defects with an emphasis on defect orientation. A circular grain ...

Rice, Marie C

2014-01-01T23:59:59.000Z

52

Two dimensional properties of methane adsorbed on porous silicon  

E-Print Network [OSTI]

TWO DIMENSIONAL PROPERTIES OF METHANE ADSORBED ON POROUS SILICON A Thesis by RICHARD FRANKLIN TENNIS Submitted to the Office of Graduate Studies of Texas ASM University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE May 1989 Major Subject: Physics TWO DIMENSIONAL PROPERTIES OF METHANE ADSORBED ON POROUS SILICON A Thesis by RICHARD FRANKLIN TENNIS Approved as to style and content by: P. Kirk (C ir of Committee) Glenn olet (M er) Da J. Ernst...

Tennis, Richard Franklin

1989-01-01T23:59:59.000Z

53

Two-dimensional relativistic space charge limited current flow in the drift space  

SciTech Connect (OSTI)

Relativistic two-dimensional (2D) electrostatic (ES) formulations have been derived for studying the steady-state space charge limited (SCL) current flow of a finite width W in a drift space with a gap distance D. The theoretical analyses show that the 2D SCL current density in terms of the 1D SCL current density monotonically increases with D/W, and the theory recovers the 1D classical Child-Langmuir law in the drift space under the approximation of uniform charge density in the transverse direction. A 2D static model has also been constructed to study the dynamical behaviors of the current flow with current density exceeding the SCL current density, and the static theory for evaluating the transmitted current fraction and minimum potential position have been verified by using 2D ES particle-in-cell simulation. The results show the 2D SCL current density is mainly determined by the geometrical effects, but the dynamical behaviors of the current flow are mainly determined by the relativistic effect at the current density exceeding the SCL current density.

Liu, Y. L.; Chen, S. H., E-mail: chensh@ncu.edu.tw [Department of Physics, National Central University, Jhongli 32001, Taiwan (China); Koh, W. S. [A-STAR Institute of High Performance Computing, Singapore 138632 (Singapore)] [A-STAR Institute of High Performance Computing, Singapore 138632 (Singapore); Ang, L. K. [Engineering Product Development, Singapore University of Technology and Design, Singapore 138682 (Singapore)] [Engineering Product Development, Singapore University of Technology and Design, Singapore 138682 (Singapore)

2014-04-15T23:59:59.000Z

54

Paraxial Hamiltonian for photons in two-dimensional photonic crystal microstructures  

E-Print Network [OSTI]

New solid-state physics based approach is developed for analysis of the paraxial light propagation in two-dimensional (2D) photonic lattices of coupled dielectric waveguides or microcavities. In particular, using Maxwell's equations, a non-Hermitian Hamiltonian eigenproblem with respect to the spinor wave function of a photon is obtained for energy-dissipating photonic microstructures. The Hamiltonian is suitable for almost the entire subclass of 2D structures encompassing arrays of semiconductor microcavities and microstructured photonic crystal fibers, characterized by light propagating mostly normal to the periodic lattice plane. Methods of numerical solution are discussed and the formalism is applied to a square array of coupled semiconductor microcavities, revealing reach possibilities for tailoring photonic band structure both in the photon energy and photon lifetime energy broadening domains. In particular, a feasibility to open a double photonic crystal band gap simultaneously in the energy and lifeti...

Boiko, D L

2007-01-01T23:59:59.000Z

55

Experimentally determining the exchange parameters of quasi-two dimensional Heisenbert magnets  

SciTech Connect (OSTI)

Though long-range magnetic order cannot occur at temperatures T > 0 in a perfect two-dimensional (2D) Heisenberg magnet, real quasi-2D materials will invariably possess nonzero inter-plane coupling J{sub {perpendicular}} driving the system to order at elevated temperatures. This process can be studied using quantum Monte Carlo calculations. However, it is difficult to test the results of these calculations experimentally since for highly anisotropic materials in which the in-plane coupling is comparable with attainable magnetic fields J{sub {perpendicular}} is necessarily very small and inaccessible directly. In addition, because of the large anisotropy, the Neel temperatures are low and difficult to determine from thermodynamic measurements. Here, we present an elegant method of assessing the calculations via two independent experimental probes: pulsed-field magnetization in fields of up to 85 T, and muon-spin rotation.

Singleton, John [Los Alamos National Laboratory; Sengupta, P [Los Alamos National Laboratory; Mcdonald, R D [Los Alamos National Laboratory; Cox, S [Los Alamos National Laboratory; Harrison, N [Los Alamos National Laboratory; Goddard, P A [UNIV OF OXFORD; Lancaster, T [UNIV OF OXFORD; Blundell, S J [UNIV OF OXFORD; Pratt, F L [RUTHERFORD APPLETON LAB; Manson, J L [EASTERN WASHINGTON UNIV; Southerland, H I [EASTERN WASHINGTON UNIV; Schlueter, J A [ANL

2008-01-01T23:59:59.000Z

56

An Ant Colony Optimization Algorithm for the 2D HP Protein Folding Problem  

E-Print Network [OSTI]

An Ant Colony Optimization Algorithm for the 2D HP Protein Folding Problem Alena Shmygelska, Rosal, the two dimensional hydrophobic-polar (2D HP) protein folding problem. We introduce an ant colony algorithm closely approaches that of specialised, state-of-the methods for 2D HP protein folding. 1

Hoos, Holger H.

57

Investigation of organometallic reaction mechanisms with one and two dimensional vibrational spectroscopy  

SciTech Connect (OSTI)

One and two dimensional time-resolved vibrational spectroscopy has been used to investigate the elementary reactions of several prototypical organometallic complexes in room temperature solution. The electron transfer and ligand substitution reactions of photogenerated 17-electron organometallic radicals CpW(CO){sub 3} and CpFe(CO){sub 2} have been examined with one dimensional spectroscopy on the picosecond through microsecond time-scales, revealing the importance of caging effects and odd-electron intermediates in these reactions. Similarly, an investigation of the photophysics of the simple Fischer carbene complex Cr(CO){sub 5}[CMe(OMe)] showed that this class of molecule undergoes an unusual molecular rearrangement on the picosecond time-scale, briefly forming a metal-ketene complex. Although time-resolved spectroscopy has long been used for these types of photoinitiated reactions, the advent of two dimensional vibrational spectroscopy (2D-IR) opens the possibility to examine the ultrafast dynamics of molecules under thermal equilibrium conditions. Using this method, the picosecond fluxional rearrangements of the model metal carbonyl Fe(CO){sub 5} have been examined, revealing the mechanism, time-scale, and transition state of the fluxional reaction. The success of this experiment demonstrates that 2D-IR is a powerful technique to examine the thermally-driven, ultrafast rearrangements of organometallic molecules in solution.

Cahoon, James Francis

2008-12-16T23:59:59.000Z

58

Hydrogen Bond Rearrangements in Water Probed with Temperature-Dependent 2D IR  

E-Print Network [OSTI]

We use temperature-dependent two-dimensional infrared spectroscopy (2D IR) of dilute HOD in H2O to investigate hydrogen bond rearrangements in water. The OD stretching frequency is sensitive to its environment, and loss ...

Nicodemus, Rebecca A.

59

Bulk-edge correspondence for two-dimensional topological insulators  

E-Print Network [OSTI]

Topological insulators can be characterized alternatively in terms of bulk or edge properties. We prove the equivalence between the two descriptions for two-dimensional solids in the single-particle picture. We give a new formulation of the $\\mathbb{Z}_{2}$-invariant, which allows for a bulk index not relying on a (two-dimensional) Brillouin zone. When available though, that index is shown to agree with known formulations. The method also applies to integer quantum Hall systems. We discuss a further variant of the correspondence, based on scattering theory.

G. M. Graf; M. Porta

2013-03-19T23:59:59.000Z

60

Experimentally determining the exchange parameters of quasi-two-dimensional Heisenberg magnets.  

SciTech Connect (OSTI)

Though long-range magnetic order cannot occur at temperatures T > 0 in a perfect two-dimensional (2D) Heisenberg magnet, real quasi-2D materials will invariably possess nonzero inter-plane coupling J{perpendicular} driving the system to order at elevated temperatures. This process can be studied using quantum Monte Carlo calculations. However, it is difficult to test the results of these calculations experimentally since for highly anisotropic materials in which the in-plane coupling is comparable with attainable magnetic fields J{perpendicular} is necessarily very small and inaccessible directly. In addition, because of the large anisotropy, the Neel temperatures are low and difficult to determine from thermodynamic measurements. Here, we present an elegant method of assessing the calculations via two independent experimental probes: pulsed-field magnetization in fields of up to 85 T, and muon-spin rotation. We successfully demonstrate the application of this method for nine metal-organic Cu-based quasi-2D magnets with pyrazine (pyz) bridges. Our results suggest the superexchange efficiency of the [Cu(HF{sub 2})(pyz){sub 2}]X family of compounds (where X can be ClO{sub 4}, BF{sub 4}, PF{sub 6}, SbF{sub 6} and AsF{sub 6}) might be controlled by the tilting of the pyz molecule with respect to the 2D planes.

Goddard, P. A.; Singleton, J.; Sengupta, P.; McDonald, R. D.; Lancaster, T.; Blundell, S. J.; Pratt, F. L.; Cox, S.; Harrison, N.; Manson, J. L.; Southerland, H. I.; Schlueter, J. A.; Materials Science Division; Univ. of Oxford; LANL; Rutherford Appleton Lab.; Eastern Washington Univ.

2008-08-19T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
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61

Superfluid Mutual-friction Coefficients from Vortex Dynamics in the Two-dimensional Galerkin-truncated Gross-Pitaevskii Equation  

E-Print Network [OSTI]

We present algorithms for the ab-initio determination of the temperature ($T$) dependence of the mutual-friction coefficients $\\alpha$ and $\\alpha'$ and the normal-fluid density $\\rho_{\\rm n}$ in the two-dimensional (2D) Galerkin-truncated Gross-Pitaevskii system. Our algorithms enable us to determine $\\alpha(T)$, even though fluctuations in 2D are considerably larger than they are in 3D. We also examine the implications of our measurements of $\\alpha'(T)$ for the Iordanskii force, whose existence is often questioned.

Vishwanath Shukla; Marc Brachet; Rahul Pandit

2014-11-23T23:59:59.000Z

62

Classification of two dimensional fixed sun angle solar sail trajectories  

E-Print Network [OSTI]

Classification of two dimensional fixed sun angle solar sail trajectories Stephen Wokes, Phil heliocentric trajectories for fixed sun angle solar sails are examined. The objective of this work (lightness factor) and Sun angle this phase space shows all possible solar sail trajectories. This phase

Roberts, Mark

63

Anomalous Hall effect in a two-dimensional electron gas  

E-Print Network [OSTI]

transport theory or the diagrammatic approach based on the Kubo- Streda linear-response formalism. The equivalence of these two methods for the two-dimensional Dirac-band graphene system has recently been shown by Sinitsyn et al.,10 who explicitly...

Nunner, Tamara S.; Sinitsyn, N. A.; Borunda, Mario F.; Dugaev, V. K.; Kovalev, A. A.; Abanov, Artem; Timm, Carsten; Jungwirth, T.; Inoue, Jun-ichiro; MacDonald, A. H.; Sinova, Jairo.

2007-01-01T23:59:59.000Z

64

IDENTIFICATION OF MATERIAL DAMAGE IN TWO DIMENSIONAL DOMAINS  

E-Print Network [OSTI]

IDENTIFICATION OF MATERIAL DAMAGE IN TWO DIMENSIONAL DOMAINS USING SQUID BASED NDE SYSTEM H on such problems entails quantitative nondestructive evaluation methods in SQUID-based NDE system [1]. It is well, SQUID based nondestructive evaluation (NDE) systems using injection current methods have been recently

65

IDENTIFICATION OF MATERIAL DAMAGE IN TWO DIMENSIONAL DOMAINS  

E-Print Network [OSTI]

IDENTIFICATION OF MATERIAL DAMAGE IN TWO DIMENSIONAL DOMAINS USING SQUID BASED NDE SYSTEM H#ort on such problems entails quantitative nondestructive evaluation methods in SQUID­based NDE system [1]. It is well nondestructive evaluation (NDE) systems using injection current methods have been recently developed [3, 4

66

Two-dimensional optimization of free-electron-laser designs  

DOE Patents [OSTI]

Off-axis, two-dimensional designs for free electron lasers are described that maintain correspondence of a light beam with a synchronous electron at an optimal transverse radius r > 0 to achieve increased beam trapping efficiency and enhanced laser beam wavefront control so as to decrease optical beam diffraction and other deleterious effects.

Prosnitz, D.; Haas, R.A.

1982-05-04T23:59:59.000Z

67

Two-dimensional optimization of free electron laser designs  

DOE Patents [OSTI]

Off-axis, two-dimensional designs for free electron lasers that maintain correspondence of a light beam with a "synchronous electron" at an optimal transverse radius r>0 to achieve increased beam trapping efficiency and enhanced laser beam wavefront control so as to decrease optical beam diffraction and other deleterious effects.

Prosnitz, Donald (Walnut Creek, CA); Haas, Roger A. (Pleasanton, CA)

1985-01-01T23:59:59.000Z

68

Optical implementability of the two-dimensional Quantum Walk  

E-Print Network [OSTI]

We propose an optical cavity implementation of the two-dimensional coined quantum walk on the line. The implementation makes use of only classical resources, and is tunable in the sense that a large number of different unitary transformations can be implemented by tuning some parameters of the device.

Eugenio Roldan; J. C. Soriano

2005-03-07T23:59:59.000Z

69

Nesting of two-dimensional irregular parts: an integrated approach  

E-Print Network [OSTI]

Nesting of two-dimensional irregular parts: an integrated approach S. Q. XIE*{, G. G. WANG{ and Y The present paper reports an intelligent computer-aided nesting (CAN) system for optimal nesting of two the utilization ratio of sheet materials. This paper also systemically reviews the nesting algorithms that were

Wang, Gaofeng Gary

70

Electronic Control of a Two-Dimensional, Knee-less,  

E-Print Network [OSTI]

of the two dimensional, knee-less, bipedal walker was originally created by Gosse [1] in 1998. Energy and prepare dozens of discrete components, the Robot Controller combines a programmable chip, programming port Power Approx. 1W Low power consumption means greater robot efficiency and longer walking time Size 3

Ruina, Andy L.

71

Fast approximate Duplicate Detection for 2D-NMR Spectra  

E-Print Network [OSTI]

, the one-dimensional plots at the axes are projections of the original two-dimensional intensity function the influences of two different atom types at the same time, e.g. 1 H (hydrogen) and 13 C (carbon). The result of a 2D-NMR measurement can be seen as an intensity function measured over two independent variables3

Hinneburg, Alexander

72

Two-dimensional materials as a new platform for atomically thin electronics and optoelectronics  

E-Print Network [OSTI]

M. S. Electronics and optoelectronics of two-dimensionalGraphene photonics and optoelectronics. Nat. Photon. 4, 611–M. S. Electronics and optoelectronics of two-dimensional

Cheng, Rui

2014-01-01T23:59:59.000Z

73

E-Print Network 3.0 - analysis ii two-dimensional Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Washington, Seattle, WA, United States Two-dimensional turbulence appears... of the phenomenology of two-dimensional turbulence as well as recent theoretical breakthroughs by...

74

Consideration of a ultracold neutron source in two-dimensional cylindrical geometry by taking simulated boundaries  

SciTech Connect (OSTI)

A new idea to calculate ultracold neutron (UCN) production by using Monte Carlo simulation method to calculate the cold neutron (CN) flux and an analytical approach to calculate the UCN production from the simulated CN flux was given. A super-thermal source (UCN source) was modeled based on an arrangement of D{sub 2}O and solid D{sub 2} (sD{sub 2}). The D{sub 2}O was investigated as the neutron moderator, and sD{sub 2} as the converter. In order to determine the required parameters, a two-dimensional (2D) neutron balance equation written in Matlab was combined with the MCNPX simulation code. The 2D neutron-transport equation in cylindrical (? ? z) geometry was considered for 330 neutron energy groups in the sD{sub 2}. The 2D balance equation for UCN and CN was solved using simulated CN flux as boundary value. The UCN source dimensions were calculated for the development of the next UCN source. In the optimal condition, the UCN flux and the UCN production rate (averaged over the sD{sub 2} volume) equal to 6.79?×?10{sup 6} cm{sup ?2}s{sup ?1} and 2.20 ×10{sup 5} cm{sup ?3}s{sup ?1}, respectively.

Gheisari, R., E-mail: gheisari@pgu.ac.ir [Physics Department, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of); Nuclear Energy Research Center, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of); Firoozabadi, M. M.; Mohammadi, H. [Department of Physics, University of Birjand, Birjand 97175 (Iran, Islamic Republic of)] [Department of Physics, University of Birjand, Birjand 97175 (Iran, Islamic Republic of)

2014-01-15T23:59:59.000Z

75

Experimental study of two-dimensional quantum Wigner solid in zero magnetic field  

SciTech Connect (OSTI)

At temperatures T ? 0, strongly interacting two-dimensional (2D) electron systems manifest characteristic insulating behaviors that are key for understanding the nature of the ground state in light of the interplay between disorder and electron-electron interaction. In contrast to the hopping conductance demonstrated in the insulating side of the metal-to-insulator transition, the ultra-high quality 2D systems exhibit nonactivated T-dependence of the conductivity even for dilute carrier concentrations down to 7×10{sup 8} cm{sup ?2}. The apparent metal-to-insulator transition (MIT) occurs for a large r{sub s} value around 40 for which a Wigner Crystalllization is expected. The magnetoresistance for a series of carrier densities in the vicinity of the transition exhibits a characteristic sign change in weak perpendicular magnetic field. Within the Wigner Crystallization regime (with r{sub s} > 40), we report an experimental observation of a characteristic nonlinear threshold behavior from a high-resolution dc dynamical response as an evidence for aWigner crystallization in high-purity GaAs 2D hole systems in zero magnetic field. The system under an increasing current drive exhibits voltage oscillations with negative differential resistance. They confirm the coexistence of a moving crystal along with striped edge states as observed for electrons on helium surfaces. Moreover, the threshold is well below the typical classical levels due to a different pinning and depinning mechanism that is possibly related to quantum processes.

Huang, Jian [Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201 (United States); Pfeiffer, L. N.; West, K. W. [Department of Electrical Engineering, Princeton University, Princeton, NJ 08544 (United States)

2014-03-31T23:59:59.000Z

76

Conductance characteristics between a normal metal and a two-dimensional Fulde-Ferrell-Larkin-Ovchinnikov superconductor: The Fulde-Ferrell state  

E-Print Network [OSTI]

The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state has received renewed interest recently due to the experimental indication of its presence in CeCoIn5, a quasi-two-dimensional (2D) d-wave superconductor. However direct evidence of the spatial...

Cui, Qinghong; Hu, Chia-Ren; Wei, J. Y. T.; Yang, Kun.

2006-01-01T23:59:59.000Z

77

IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 40, NO. 12, DECEMBER 2005 2689 A 10-Gb/s Two-Dimensional Eye-Opening  

E-Print Network [OSTI]

-Dimensional Eye-Opening Monitor in 0.13-m Standard CMOS Behnam Analui, Associate Member, IEEE, Alexander Rylyakov, Sergey Rylov, Mounir Meghelli, and Ali Hajimiri, Member, IEEE Abstract--An eye-opening monitor (EOM) architecture that can capture a two-dimensional (2-D) map of the eye diagram of a high- speed data signal has

Hajimiri, Ali

78

Transport behavior of water molecules through two-dimensional nanopores  

SciTech Connect (OSTI)

Water transport through a two-dimensional nanoporous membrane has attracted increasing attention in recent years thanks to great demands in water purification and desalination applications. However, few studies have been reported on the microscopic mechanisms of water transport through structured nanopores, especially at the atomistic scale. Here we investigate the microstructure of water flow through two-dimensional model graphene membrane containing a variety of nanopores of different size by using molecular dynamics simulations. Our results clearly indicate that the continuum flow transits to discrete molecular flow patterns with decreasing pore sizes. While for pores with a diameter ?15 Å water flux exhibits a linear dependence on the pore area, a nonlinear relationship between water flux and pore area has been identified for smaller pores. We attribute this deviation from linear behavior to the presence of discrete water flow, which is strongly influenced by the water-membrane interaction and hydrogen bonding between water molecules.

Zhu, Chongqin; Li, Hui; Meng, Sheng, E-mail: smeng@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2014-11-14T23:59:59.000Z

79

Topological defect motifs in two-dimensional Coulomb clusters  

E-Print Network [OSTI]

The most energetically favourable arrangement of low-density electrons in an infinite two-dimensional plane is the ordered triangular Wigner lattice. However, in most instances of contemporary interest one deals instead with finite clusters of strongly interacting particles localized in potential traps, for example, in complex plasmas. In the current contribution we study distribution of topological defects in two-dimensional Coulomb clusters with parabolic lateral confinement. The minima hopping algorithm based on molecular dynamics is used to efficiently locate the ground- and low-energy metastable states, and their structure is analyzed by means of the Delaunay triangulation. The size, structure and distribution of geometry-induced lattice imperfections strongly depends on the system size and the energetic state. Besides isolated disclinations and dislocations, classification of defect motifs includes defect compounds --- grain boundaries, rosette defects, vacancies and interstitial particles. Proliferatio...

Radzvilavi?ius, A; 10.1088/0953-8984/23/38/385301

2012-01-01T23:59:59.000Z

80

Suspended two-dimensional electron and hole gases  

SciTech Connect (OSTI)

We report on the fabrication of fully suspended two-dimensional electron and hole gases in III-V heterostructures. Low temperature transport measurements verify that the properties of the suspended gases are only slightly degraded with respect to the non-suspended gases. Focused ion beam technology is used to pattern suspended nanostructures with minimum damage from the ion beam, due to the small width of the suspended membrane.

Kazazis, D.; Bourhis, E.; Gierak, J.; Gennser, U. [Laboratoire de Photonique et de Nanostructures, CNRS-LPN, Route de Nozay, 91460 Marcoussis (France); Bourgeois, O. [Institut Néel, CNRS-UJF, BP 166, 38042 Grenoble Cedex 9 (France); Antoni, T. [Laboratoire de Photonique et de Nanostructures, CNRS-LPN, Route de Nozay, 91460 Marcoussis, France and Laboratoire Kastler Brossel, Université Pierre et Marie Curie, 4 Place Jussieu, 75005 Paris (France)

2013-12-04T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Quantum Hamilton-Jacobi Approach to Two Dimensional Singular Oscillator  

E-Print Network [OSTI]

We have obtained the solutions of two dimensional singular oscillator which is known as the quantum Calogero-Sutherland model both in cartesian and parabolic coordinates within the framework of quantum Hamilton Jacobi formalism. Solvability conditions and eigenfunctions are obtained by using the singularity structures of quantum momentum functions under some conditions. New potentials are generated by using the first two states of singular oscillator for parabolic coordinates.

Ozlem Yesiltas; Bengu Demircioglu

2007-08-20T23:59:59.000Z

82

The Study of Two-dimensional Polytropic Stars  

E-Print Network [OSTI]

In this article we have studied the structure of hypothetical two-dimensional polytropic stars. Considering some academic interest, we have developed a formalism to investigate some of the gross properties of such stellar objects. However, we strongly believe that the formalism developed here may be prescribed as class problem for post-graduate level students in physics or a post-graduate dissertation project work in physics.

Sanchari De; Somenath Chakrabarty

2014-04-28T23:59:59.000Z

83

X-ray tests of a two-dimensional stigmatic imaging scheme with variable magnifications  

SciTech Connect (OSTI)

A two-dimensional stigmatic x-ray imaging scheme, consisting of two spherically bent crystals, one concave and one convex, was recently proposed [M. Bitter et al., Rev. Sci. Instrum. 83, 10E527 (2012)]. The Bragg angles and the radii of curvature of the two crystals of this imaging scheme are matched to eliminate the astigmatism and to satisfy the Bragg condition across both crystal surfaces for a given x-ray energy. In this paper, we consider more general configurations of this imaging scheme, which allow us to vary the magnification for a given pair of crystals and x-ray energy. The stigmatic imaging scheme has been validated for the first time by imaging x-rays generated by a micro-focus x-ray source with source size of 8.4 ?m validated by knife-edge measurements. Results are presented from imaging the tungsten L?1 emission at 8.3976 keV, using a convex Si-422 crystal and a concave Si-533 crystal with 2d-spacings of 2.21707 Å and 1.65635 Å and radii of curvature of 500 ± 1 mm and 823 ± 1 mm, respectively, showing a spatial resolution of 54.9 ?m. This imaging scheme is expected to be of interest for the two-dimensional imaging of laser produced plasmas.

Lu, J., E-mail: jlu@pppl.gov [Key Laboratory of Optoelectronic Technology and System of Ministry of Education, Chongqing University, Chongqing 400030 (China); Bitter, M.; Hill, K. W.; Delgado-Aparicio, L. F.; Efthimion, P. C.; Pablant, N. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Beiersdorfer, P. [Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Caughey, T. A.; Brunner, J. [Inrad Optics, 181 Legrand Avenue, Northvale, New Jersey 07647 (United States)

2014-11-15T23:59:59.000Z

84

Effects of some common geological features on two-dimensional variably saturated flow  

SciTech Connect (OSTI)

This paper presents results of unsaturated flow simulations undertaken as an auxiliary analysis for the Iterative Performance Assessment (IPA) project, one of the approaches adopted by the U.S. NRC to develop repository license application review capabilities. The effects on flow of common geological features, such as nonhorizontal stratification and vertical or near-vertical fault zones intersecting the strata, in a two-dimensional (2D) domain are studied. Results indicate that the presence of layers and crosscutting fault zones tend to induce three-dimensional (3D) unstable flows in the unsaturated zone. The instability is manifested in our simulations by an oscillatory behavior of steady state. This numerical instability imposes extremely stringent criteria on the time step used in the simulation. Finally, once stable steady-state solutions are attained, the effect of the crossing point in the matrix-fault unsaturated hydraulic conductivity curve on groundwater flux vectors and moisture content distributions is studied.

Bagtzoglou, A.C.; Ababou, R.; Sagar, B.; Islam, M.R. [Southwest Research Institute, San Antonio, TX (United States)

1993-12-31T23:59:59.000Z

85

Two-dimensional magnetohydrodynamic studies of implosion modes of nested wire array z-pinches  

SciTech Connect (OSTI)

Implosion dynamics of nested wire arrays in (r, ?) geometry was studied with two-dimensional magnetohydrodynamic (2D MHD) simulations. Three different implosion modes are obtained by just changing the wire number of the outer array, when the other conditions, such as the initial radius, length, mass of each array, the wire number of the inner array, and the discharge voltage waveform, are fixed. Simulation results show that the effect of discrete wires, which cannot be described by the thin shell inductive model, will influence the distribution of current between the outer and inner arrays at the early stage, and the discrepancy between results from MHD and thin shell model increases with the interwire gap of the outer array.

Huang, Jun; Ding, Ning, E-mail: ding-ning@iapcm.ac.cn; Xue, Chuang; Sun, Shunkai [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

2014-07-15T23:59:59.000Z

86

Two-dimensional modeling of sodium boiling in a simulated LMFBR loss-of-flow test  

SciTech Connect (OSTI)

Loss-of-flow (LOF) accidents are of major importance in LMFBR safety. Tests have been performed to simulate the simultaneous failure of all primary pumps and reactor shutdown systems in a 37-pin electrically heated test bundle installed in the KNS sodium boiling loop at the Institute of Reactor Development, Karlsruhe. The tests simulated LOF conditions of the German prototype LMFBR, the SNR 300. The main objectives of these tests were to characterize the transient boiling development to cladding dryout and to provide data for validation of sodium boiling codes. One particular LOF test, designated L22, at full power was selected as a benchmark exercise for comparison of several codes at the Eleventh Meeting of the Liquid Metal Boiling Working Group (LMBWG) held in Grenoble, France, in October 1984. In this paper, the results of the calculations performed at ORNL with the two-dimensional (2-D) boiling code THORAX are presented.

Rose, S.D.

1984-01-01T23:59:59.000Z

87

Three-dimensional liver motion tracking using real-time two-dimensional MRI  

SciTech Connect (OSTI)

Purpose: Combined magnetic resonance imaging (MRI) systems and linear accelerators for radiotherapy (MR-Linacs) are currently under development. MRI is noninvasive and nonionizing and can produce images with high soft tissue contrast. However, new tracking methods are required to obtain fast real-time spatial target localization. This study develops and evaluates a method for tracking three-dimensional (3D) respiratory liver motion in two-dimensional (2D) real-time MRI image series with high temporal and spatial resolution. Methods: The proposed method for 3D tracking in 2D real-time MRI series has three steps: (1) Recording of a 3D MRI scan and selection of a blood vessel (or tumor) structure to be tracked in subsequent 2D MRI series. (2) Generation of a library of 2D image templates oriented parallel to the 2D MRI image series by reslicing and resampling the 3D MRI scan. (3) 3D tracking of the selected structure in each real-time 2D image by finding the template and template position that yield the highest normalized cross correlation coefficient with the image. Since the tracked structure has a known 3D position relative to each template, the selection and 2D localization of a specific template translates into quantification of both the through-plane and in-plane position of the structure. As a proof of principle, 3D tracking of liver blood vessel structures was performed in five healthy volunteers in two 5.4 Hz axial, sagittal, and coronal real-time 2D MRI series of 30 s duration. In each 2D MRI series, the 3D localization was carried out twice, using nonoverlapping template libraries, which resulted in a total of 12 estimated 3D trajectories per volunteer. Validation tests carried out to support the tracking algorithm included quantification of the breathing induced 3D liver motion and liver motion directionality for the volunteers, and comparison of 2D MRI estimated positions of a structure in a watermelon with the actual positions. Results: Axial, sagittal, and coronal 2D MRI series yielded 3D respiratory motion curves for all volunteers. The motion directionality and amplitude were very similar when measured directly as in-plane motion or estimated indirectly as through-plane motion. The mean peak-to-peak breathing amplitude was 1.6 mm (left-right), 11.0 mm (craniocaudal), and 2.5 mm (anterior-posterior). The position of the watermelon structure was estimated in 2D MRI images with a root-mean-square error of 0.52 mm (in-plane) and 0.87 mm (through-plane). Conclusions: A method for 3D tracking in 2D MRI series was developed and demonstrated for liver tracking in volunteers. The method would allow real-time 3D localization with integrated MR-Linac systems.

Brix, Lau, E-mail: lau.brix@stab.rm.dk [Department of Procurement and Clinical Engineering, Region Midt, Olof Palmes Allé 15, 8200 Aarhus N, Denmark and MR Research Centre, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark)] [Department of Procurement and Clinical Engineering, Region Midt, Olof Palmes Allé 15, 8200 Aarhus N, Denmark and MR Research Centre, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark); Ringgaard, Steffen [MR Research Centre, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark)] [MR Research Centre, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark); Sørensen, Thomas Sangild [Department of Computer Science, Aarhus University, Aabogade 34, 8200 Aarhus N, Denmark and Department of Clinical Medicine, Aarhus University, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark)] [Department of Computer Science, Aarhus University, Aabogade 34, 8200 Aarhus N, Denmark and Department of Clinical Medicine, Aarhus University, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark); Poulsen, Per Rugaard [Department of Clinical Medicine, Aarhus University, Brendstrupgaardsvej 100, 8200 Aarhus N, Denmark and Department of Oncology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C (Denmark)] [Department of Clinical Medicine, Aarhus University, Brendstrupgaardsvej 100, 8200 Aarhus N, Denmark and Department of Oncology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C (Denmark)

2014-04-15T23:59:59.000Z

88

July 24, 2011 15:30 World Scientific Review Volume -9.75in x 6.5in HadzibabicDalibard BKT physics with two-dimensional atomic gases  

E-Print Network [OSTI]

, and the more conventional Bose­Einstein condensation that is expected for an ideal 2D Bose gas confined quasi two-dimensional (2D) samples by freezing out one degree of freedom with laser beams, and we de of the gas, monitor the occurrence of a BKT-driven phase transition, and observe thermally activated

Dalibard, Jean

89

Correction-to-scaling exponent for two-dimensional percolation  

SciTech Connect (OSTI)

We show that the correction-to-scaling exponents in two-dimensional percolation are bounded by {Omega}{<=}72/91, {omega}=D{Omega}{<=}3/2, and {Delta}{sub 1}={nu}{omega}{<=}2, based upon Cardy's result for the crossing probability on an annulus. The upper bounds are consistent with many previous measurements of site percolation on square and triangular lattices and new measurements for bond percolation, suggesting that they are exact. They also agree with exponents for hulls proposed recently by Aharony and Asikainen, based upon results of den Nijs. A corrections scaling form evidently applicable to site percolation is also found.

Ziff, Robert M. [Center for the Study of Complex Systems and Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2011-02-15T23:59:59.000Z

90

Optical and electronic properties of two dimensional graphitic silicon carbide  

E-Print Network [OSTI]

Optical and electronic properties of two dimensional few layers graphitic silicon carbide (GSiC), in particular monolayer and bilayer, are investigated by density functional theory and found different from that of graphene and silicene. Monolayer GSiC has direct bandgap while few layers exhibit indirect bandgap. The bandgap of monolayer GSiC can be tuned by an in-plane strain. Properties of bilayer GSiC are extremely sensitive to the interlayer distance. These predictions promise that monolayer GSiC could be a remarkable candidate for novel type of light-emitting diodes utilizing its unique optical properties distinct from graphene, silicene and few layers GSiC.

Lin, Xiao; Lin, Shisheng; Hakro, Ayaz Ali; Cao, Te; Chen, Hongsheng; Zhang, Baile

2012-01-01T23:59:59.000Z

91

Monte Carlo Simulations of the two-dimensional dipolar fluid  

E-Print Network [OSTI]

We study a two-dimensional fluid of dipolar hard disks by Monte Carlo simulations in a square with periodic boundary conditions and on the surface of a sphere. The theory of the dielectric constant and the asymptotic behaviour of the equilibrium pair correlation function in the fluid phase is derived for both geometries. After having established the equivalence of the two methods we study the stability of the liquid phase in the canonical ensemble. We give evidence of a phase made of living polymers at low temperatures and provide a tentative phase diagram.

Caillol, Jean-Michel

2015-01-01T23:59:59.000Z

92

Two-dimensional random walk in a bounded domain  

E-Print Network [OSTI]

In a recent Letter Ciftci and Cakmak [EPL 87, 60003 (2009)] showed that the two dimensional random walk in a bounded domain, where walkers which cross the boundary return to a base curve near origin with deterministic rules, can produce regular patterns. Our numerical calculations suggest that the cumulative probability distribution function of the returning walkers along the base curve is a Devil's staircase, which can be explained from the mapping of these walks to a non-linear stochastic map. The non-trivial probability distribution function(PDF) is a universal feature of CCRW characterized by the fractal dimension d=1.75(0) of the PDF bounding curve.

Mahashweta Basu; P. K. Mohanty

2009-10-30T23:59:59.000Z

93

Dynamics of quasi-two-dimensional turbulent jets  

E-Print Network [OSTI]

In turbulent jets, fluid is driven by momentum from an orifice into an environ- ment filled with similar fluid. The complexity of this flow, which has been studied for more than 80 years (see e.g. List, 1982, for a detailed review), resides in its turbulent... in time with an accuracy of approximately 1 %. We conducted two distinct sets of experiments using two qualitatively different techniques: dye tracking and particle image velocimetry (PIV). 7 2 Meandering and self-similarity of quasi-two-dimensional jets x...

Landel, Julien Rémy Dominique Gérard

2012-11-13T23:59:59.000Z

94

Magnus force in discrete and continuous two-dimensional superfluids  

SciTech Connect (OSTI)

Motion of vortices in two-dimensional superfluids in the classical limit is studied by solving the Gross-Pitaevskii equation numerically on a uniform lattice. We find that, in the presence of a superflow directed along one of the main lattice periods, vortices move with the superflow on fine lattices but perpendicular to it on coarse ones. We interpret this result as a transition from the full Magnus force in a Galilean-invariant limit to vanishing effective Magnus force in a discrete system, in agreement with the existing experiments on vortex motion in Josephson junction arrays.

Gecse, Z.; Khlebnikov, S. [Department of Physics, Purdue University, West Lafayette, Indiana 47907 (United States)

2005-08-01T23:59:59.000Z

95

CASL - Analysis of Two-Dimensional Lattice Physics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone6Energy, science, andAnalysis of Two-Dimensional Lattice Physics

96

Two-dimensional random walk in a bounded domain  

E-Print Network [OSTI]

In a recent Letter Ciftci and Cakmak [EPL 87, 60003 (2009)] showed that the two dimensional random walk in a bounded domain, where walkers which cross the boundary return to a base curve near origin with deterministic rules, can produce regular patterns. Our numerical calculations suggest that the cumulative probability distribution function of the returning walkers along the base curve is a Devil's staircase, which can be explained from the mapping of these walks to a non-linear stochastic map. The non-trivial probability distribution function(PDF) is a universal feature of CCRW characterized by the fractal dimension d=1.75(0) of the PDF bounding curve.

Basu, Mahashweta

2010-01-01T23:59:59.000Z

97

Two-dimensional gravity with a dynamical aether  

E-Print Network [OSTI]

We investigate the two-dimensional behavior of gravity coupled to a dynamical unit timelike vector field, i.e. "Einstein-aether theory". The classical solutions of this theory in two dimensions depend on one coupling constant. When this coupling is positive the only solutions are (i) flat spacetime with constant aether, (ii) de Sitter or anti-de Sitter spacetimes with a uniformly accelerated unit vector invariant under a two-dimensional subgroup of SO(2,1) generated by a boost and a null rotation, and (iii) a non-constant curvature spacetime that has no Killing symmetries and contains singularities. In this case the sign of the curvature is determined by whether the coupling is less or greater than one. When instead the coupling is negative only solutions (i) and (iii) are present. This classical study of the behavior of Einstein-aether theory in 1+1 dimensions may provide a starting point for further investigations into semiclassical and fully quantum toy models of quantum gravity with a dynamical preferred frame.

Christopher Eling; Ted Jacobson

2006-08-09T23:59:59.000Z

98

Two-dimensional gravity with a dynamical aether  

SciTech Connect (OSTI)

We investigate the two-dimensional behavior of gravity coupled to a dynamical unit timelike vector field, i.e. ''Einstein-aether theory.'' The classical solutions of this theory in two dimensions depend on one coupling constant. When this coupling is positive the only solutions are (i) flat spacetime with constant aether (ii) de Sitter or anti-de Sitter spacetimes with a uniformly accelerated unit vector invariant under a two-dimensional subgroup of SO(2,1) generated by a boost and a null rotation, and (iii) a nonconstant curvature spacetime that has no Killing symmetries and contains singularities. In this case the sign of the curvature is determined by whether the coupling is less or greater than one. When instead the coupling is negative only solutions (i) and (iii) are present. This classical study of the behavior of Einstein-aether theory in 1+1 dimensions may provide a starting point for further investigations into semiclassical and fully quantum toy models of quantum gravity with a dynamical preferred frame.

Eling, Christopher; Jacobson, Ted [Department of Physics, University of Maryland, College Park, Maryland 20742-4111 (United States)

2006-10-15T23:59:59.000Z

99

Two-dimensional symmetry-protected topological orders and their protected gapless edge excitations  

SciTech Connect (OSTI)

Topological insulators in free fermion systems have been well characterized and classified. However, it is not clear in strongly interacting boson or fermion systems what symmetry-protected topological orders exist. In this paper, we present a model in a two-dimensional (2D) interacting spin system with nontrivial onsite Z{sub 2} symmetry-protected topological order. The order is nontrivial because we can prove that the one-dimensional (1D) system on the boundary must be gapless if the symmetry is not broken, which generalizes the gaplessness of Wess-Zumino-Witten model for Lie symmetry groups to any discrete symmetry groups. The construction of this model is related to a nontrivial 3-cocycle of the Z{sub 2} group and can be generalized to any symmetry group. It potentially leads to a complete classification of symmetry-protected topological orders in interacting boson and fermion systems of any dimension. Specifically, this exactly solvable model has a unique gapped ground state on any closed manifold and gapless excitations on the boundary if Z{sub 2} symmetry is not broken. We prove the latter by developing the tool of a matrix product unitary operator to study the nonlocal symmetry transformation on the boundary and reveal the nontrivial 3-cocycle structure of this transformation. Similar ideas are used to construct a 2D fermionic model with onsite Z{sub 2} symmetry-protected topological order.

Chen Xie [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Liu Zhengxin; Wen Xiaogang [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Institute for Advanced Study, Tsinghua University, Beijing, 100084 (China)

2011-12-15T23:59:59.000Z

100

Characterization of two-dimensional hexagonal boron nitride using scanning electron and scanning helium ion microscopy  

SciTech Connect (OSTI)

Characterization of the structural and physical properties of two-dimensional (2D) materials, such as layer number and inelastic mean free path measurements, is very important to optimize their synthesis and application. In this study, we characterize the layer number and morphology of hexagonal boron nitride (h-BN) nanosheets on a metallic substrate using field emission scanning electron microscopy (FE-SEM) and scanning helium ion microscopy (HIM). Using scanning beams of various energies, we could analyze the dependence of the intensities of secondary electrons on the thickness of the h-BN nanosheets. Based on the interaction between the scanning particles (electrons and helium ions) and h-BN nanosheets, we deduced an exponential relationship between the intensities of secondary electrons and number of layers of h-BN. With the attenuation factor of the exponential formula, we calculate the inelastic mean free path of electrons and helium ions in the h-BN nanosheets. Our results show that HIM is more sensitive and consistent than FE-SEM for characterizing the number of layers and morphology of 2D materials.

Guo, Hongxuan, E-mail: Guo.hongxuan@nims.go.jp, E-mail: msxu@zju.edu.cn [Global Research Center for Environment and Energy Based on Nanomaterials Science National Institute for Materials Science (NIMS) 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Gao, Jianhua; Ishida, Nobuyuki [International Center for Young Scientists, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Xu, Mingsheng, E-mail: Guo.hongxuan@nims.go.jp, E-mail: msxu@zju.edu.cn [State Key Laboratory of Silicon Materials, Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Fujita, Daisuke [Advanced Key Technologies Division, Global Research Center for Environment and Energy Based on Nanomaterials Science, and International Center for Young Scientists, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

2014-01-20T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Measurement of countercurrent phase separation and distribution in a two-dimensional test section  

SciTech Connect (OSTI)

The degree of phase separation that occurs in the core of a pressurized water reactor (PWR) during various postulated accidents is an important consideration for studying the course of events during such accidents. The dependence of countercurrent phase separation and distribution phenomena on flow quality, mass flux and system geometry was studied experimentally in a two-dimensional (2-D) test section. A two-phase (air/water) mixture flowed upwards and single-phase water flowed downward along one side of the test section. This countercurrent flow configuration was intended to simulate the so-called chimney effect in the diabatic JAERI 2-D experiments in Japan. A large air/water loop used with a 91.44 cm x 91.44 cm x 1.27 cm test section to study phase separation and distribution effects. A traversing single beam gamma-densitometer was used to measure the chordal average void fractions at several elevations along the test section. Cross-plots between various flow conditions and geometries were made. An error analysis giving the total error in the void fraction measurements was also performed. High speed photographs were also made of the flow structure, to provide information on flow regimes. The photographic records and the void fraction and hydraulic inflow/outflow data are presented in a form suitable for the assessment of advanced generation computer codes (e.g., TRAC).

Bukhari, K M; Lahey, Jr, R T

1984-01-01T23:59:59.000Z

102

Effect of disorder on the superfluid transition in two-dimensional systems  

SciTech Connect (OSTI)

In recent experiments on thin {sup 4}He films absorbed to rough surfaces Luhman and Hallock [Phys. Rev. Lett. 93, 086106 (2004)] attempted to observe Kosterlitz-Thouless (KT) features of the superfluid-normal transition of this strongly disordered two-dimensional (2D) bosonic system. It came as a surprise that while peak of dissipation was measured for a wide range of surface roughness there were no indications of the theoretically expected universal jump of the areal superfluid density for the strongly disordered samples. We test the hypothesis that this unusual behavior is a manifestation of finite-size effects by numerical study of the corresponding 2D bosonic model with strong diagonal disorder. We demonstrate that the discontinuous features of the underlying KT transition are severely smoothed out for finite system sizes (or finite frequency measurements). We resolve the universal discontinuity of the areal superfluid density by fitting our data to the KT renormalization group equations for finite systems. In analogy to our simulations, we suggest that in experiments on strongly disordered 2D bosonic systems the very existence of the KT scenario can and should be revealed only from a proper finite-size scaling of the data (for {sup 4}He films finite-size scaling can be effectively controlled by the scaling of finite frequency of measurements). We also show relevance of our conclusions for a wider class of systems, such as superconducting granular films, Josephson junction arrays, and ultracold atomic gases, where similar difficulties appear in experiments designed to verify KT transition (especially in disordered cases)

Balabanyan, Karen G. [Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003 (United States)

2007-04-01T23:59:59.000Z

103

Possible diminution of impurity pair breaking for triplet pairing superconductivity in two-dimensional or quasi-two-dimensional, weakly localized, nearly magnetic systems  

SciTech Connect (OSTI)

We propose a conjecture according to which, as a consequence of weak localization in two-dimensional, nearly magnetic itinerant paramagnets, the pair-breaking parameter due to normal impurity scattering, in triplet pairing superconductivity, may be reduced at low enough temperature. It might then, in principle, become easier to observe triplet pairing superconductivity in dirty two-dimensional or quasi-two-dimensional metals, than in three-dimensional ones; thus some recently observed puzzling superconductive behaviors should be reexamined.

Beal-Monod, M.T.; Ebisawa, H.; Fukuyama, H.

1984-08-01T23:59:59.000Z

104

Topological Hofstadter Insulators in a Two-Dimensional Quasicrystal  

E-Print Network [OSTI]

We investigate the properties of a two-dimensional quasicrystal in the presence of a uniform magnetic field. In this configuration, the density of states (DOS) displays a Hofstadter butterfly-like structure when it is represented as a function of the magnetic flux per tile. We show that the low-DOS regions of the energy spectrum are associated with chiral edge states, in direct analogy with the Chern insulators realized with periodic lattices. We establish the topological nature of the edge states by computing the topological Chern number associated with the bulk of the quasicrystal. This topological characterization of the non-periodic lattice is achieved through a local (real-space) topological marker. This work opens a route for the exploration of topological insulating materials in a wide range of non-periodic lattice systems, including photonic crystals and cold atoms in optical lattices.

Duc-Thanh Tran; Alexandre Dauphin; Nathan Goldman; Pierre Gaspard

2015-03-17T23:59:59.000Z

105

Quantum Emission from Two-Dimensional Black Holes  

E-Print Network [OSTI]

We investigate Hawking radiation from two-dimensional dilatonic black holes using standard quantization techniques. In the background of a collapsing black hole solution the Bogoliubov coefficients can be exactly determined. In the regime after the black hole has settled down to an `equilibrium' state but before the backreaction becomes important these give the known result of a thermal distribution of Hawking radiation at temperature lambda/(2pi). The density matrix is computed in this regime and shown to be purely thermal. Similar techniques can be used to derive the stress tensor. The resulting expression agrees with the derivation based on the conformal anomaly and can be used to incorporate the backreaction. Corrections to the thermal density matrix are also examined, and it is argued that to leading order in perturbation theory the effect of the backreaction is to modify the Bogoliubov transformation, but not in a way that restores information lost to the black holes.

Steven B. Giddings; W. M. Nelson

2009-11-27T23:59:59.000Z

106

Electromagnetic two-dimensional analysis of trapped-ion eigenmodes  

SciTech Connect (OSTI)

A two-dimensional electromagnetic analysis of the trapped-ion instability for the tokamak case with ..beta.. not equal to 0 has been made, based on previous work in the electrostatic limit. The quasineutrality condition and the component of Ampere's law along the equilibrium magnetic field are solved for the perturbed electrostatic potential and the component of the perturbed vector potential along the equilibrium magnetic field. The general integro-differential equations are converted into a matrix eigenvalue-eigenfunction problem by expanding in cubic B-spline finite elements in the minor radius and in Fourier harmonics in the poloidal angle. A model MHD equilibrium with circular, concentric magnetic surfaces and large aspect ratio is used which is consistent with our assemption that B << 1. The effect on the trapped-ion mode of including these electromagnetic extensions to the calculation is considered, and the temperature (and ..beta..) scaling of the mode frequency is shown and discussed.

Kim, D.; Rewoldt, G.

1984-11-01T23:59:59.000Z

107

High speed two-dimensional optical beam position detector  

SciTech Connect (OSTI)

Disclosed is the design of a high speed two-dimensional optical beam position detector which outputs the X and Y displacement and total intensity linearly. The experimental detector measures the displacement from DC to 123 MHz and the intensity of an optical spot in a similar way as a conventional quadrant photodiode detector. The design uses four discrete photodiodes and simple dedicated optics for the position decomposition which enables higher spatial accuracy and faster electronic processing than conventional detectors. Measurements of the frequency response and the spatial sensitivity demonstrate high suitability for atomic force microscopy, scanning probe data storage applications, and wideband wavefront sensing. The operation principle allows for position measurements up to 20 GHz and more in bandwidth.

Rutten, Paul Edmond [Maypa B.V., Bijsters 2, 5131 NW, Alphen (Netherlands)

2011-07-15T23:59:59.000Z

108

Phase diagram of two-dimensional hard ellipses  

E-Print Network [OSTI]

We report the phase diagram of two-dimensional hard ellipses as obtained from replica exchange Monte Carlo simulations. The replica exchange is implemented by expanding the isobaric ensemble in pressure. The phase diagram shows four regions: isotropic, nematic, plastic, and solid (letting aside the hexatic phase at the isotropic-plastic two-step transition [PRL 107, 155704 (2011)]). At low anisotropies, the isotropic fluid turns into a plastic phase which in turn yields a solid for increasing pressure (area fraction). Intermediate anisotropies lead to a single first order transition (isotropic-solid). Finally, large anisotropies yield an isotropic-nematic transition at low pressures and a high-pressure nematic-solid transition. We obtain continuous isotropic-nematic transitions. For the transitions involving quasi-long-range positional ordering, i. e. isotropic-plastic, isotropic-solid, and nematic-solid, we observe bimodal probability density functions. This supports first order transition scenarios.

Gustavo Bautista-Carbajal; Gerardo Odriozola

2014-05-09T23:59:59.000Z

109

Local diamagnetic susceptibility of quasi-two-dimensional graphite  

SciTech Connect (OSTI)

A sample of quasi-two-dimensional graphite (QTDG) whose magnetic properties are described within the Dirac fermion model is investigated by the nuclear magnetic resonance (NMR) and scanning tunneling microscopy (STM) techniques. The broad spectrum of the sample points to a large dispersion of crystallite sizes in this system, which is also confirmed by STM data. It is established that the local diamagnetic susceptibility may substantially exceed the average value over the sample and reaches an abnormally high value of -1.3 Multiplication-Sign 10{sup -4} emu/g at T = 4.2 K, which is greater than the corresponding value of highly oriented graphite by a factor of four.

Nikolaev, E. G., E-mail: nikolaev@kapitza.ras.ru [Russian Academy of Sciences, Kapitsa Institute for Physical Problems (Russian Federation); Kotosonov, A. S. [OAO NIIgrafit (Russian Federation)] [OAO NIIgrafit (Russian Federation); Shalashugina, E. A.; Troyanovskii, A. M. [Russian Academy of Sciences, Kapitsa Institute for Physical Problems (Russian Federation)] [Russian Academy of Sciences, Kapitsa Institute for Physical Problems (Russian Federation); Tsebro, V. I. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)] [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

2013-08-15T23:59:59.000Z

110

A ballistic two-dimensional-electron-gas Andreev interferometer  

SciTech Connect (OSTI)

We report the realization and investigation of a ballistic Andreev interferometer based on an InAs two dimensional electron gas coupled to a superconducting Nb loop. We observe strong magnetic modulations in the voltage drop across the device due to quasiparticle interference within the weak-link. The interferometer exhibits flux noise down to ?80???{sub 0}/?(Hz) and a robust behavior in temperature with voltage oscillations surviving up to ?7?K. Besides this remarkable performance, the device represents a crucial first step for the realization of a fully-tunable ballistic superconducting magnetometer and embodies a potential advanced platform for the investigation of Majorana bound states, non-local entanglement of Cooper pairs, as well as the manipulation and control of spin triplet correlations.

Amado, M., E-mail: mario.amadomontero@sns.it; Fornieri, A.; Sorba, L.; Giazotto, F., E-mail: f.giazotto@sns.it [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa (Italy); Biasiol, G. [CNR-IOM, Laboratorio TASC, Area Science Park, I-34149 Trieste (Italy)

2014-06-16T23:59:59.000Z

111

Two-dimensional modeling of nickel electrodeposition in LIGA microfabrication.  

SciTech Connect (OSTI)

Two-dimensional processes of nickel electrodeposition in LIGA microfabrication were modeled using the finite-element method and a fully coupled implicit solution scheme via Newtons technique. Species concentrations, electrolyte potential, flow field, and positions of the moving deposition surfaces were computed by solving the species-mass, charge, and momentum conservation equations as well as pseudo-solid mesh-motion equations that employ an arbitrary Lagrangian-Eulerian (ALE) formulation. Coupling this ALE approach with repeated re-meshing and re-mapping makes it possible to track the entire transient deposition processes from start of deposition until the trenches are filled, thus enabling the computation of local current densities that influence the microstructure and functional/mechanical properties of the deposit.

Evans, Gregory Herbert (Sandia National Laboratories, Livermore, CA); Chen, Ken Shuang

2003-07-01T23:59:59.000Z

112

Topological states in two-dimensional optical lattices  

SciTech Connect (OSTI)

We present a general analysis of two-dimensional optical lattice models that give rise to topologically nontrivial insulating states. We identify the main ingredients of the lattice models that are responsible for the nontrivial topological character and argue that such states can be realized within a large family of realistic optical lattice Hamiltonians with cold atoms. We focus our quantitative analysis on the properties of topological states with broken time-reversal symmetry specific to cold-atom settings. In particular, we analyze finite-size effects, multiorbital phenomena that give rise to a variety of distinct topological states and transitions between them, the dependence on the trap geometry, and, most importantly, the behavior of the edge states for different types of soft and hard boundaries. Furthermore, we demonstrate the possibility of experimentally detecting the topological states through light Bragg scattering of the edge and bulk states.

Stanescu, Tudor D. [Condensed Matter Theory Center and Joint Quantum Institute, Department of Physics, University of Maryland, College Park, Maryland 20742-4111 (United States); Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States); Galitski, Victor; Das Sarma, S. [Condensed Matter Theory Center and Joint Quantum Institute, Department of Physics, University of Maryland, College Park, Maryland 20742-4111 (United States)

2010-07-15T23:59:59.000Z

113

Reconnection events in two-dimensional Hall magnetohydrodynamic turbulence  

SciTech Connect (OSTI)

The statistical study of magnetic reconnection events in two-dimensional turbulence has been performed by comparing numerical simulations of magnetohydrodynamics (MHD) and Hall magnetohydrodynamics (HMHD). The analysis reveals that the Hall term plays an important role in turbulence, in which magnetic islands simultaneously reconnect in a complex way. In particular, an increase of the Hall parameter, the ratio of ion skin depth to system size, broadens the distribution of reconnection rates relative to the MHD case. Moreover, in HMHD the local geometry of the reconnection region changes, manifesting bifurcated current sheets and quadrupolar magnetic field structures in analogy to laminar studies, leading locally to faster reconnection processes in this case of reconnection embedded in turbulence. This study supports the idea that the global rate of energy dissipation is controlled by the large scale turbulence, but suggests that the distribution of the reconnection rates within the turbulent system is sensitive to the microphysics at the reconnection sites.

Donato, S.; Servidio, S.; Carbone, V. [Dipartimento di Fisica, Universita della Calabria, I-87036 Cosenza (Italy); Dmitruk, P. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Fisica de Buenos Aires, CONICET, Buenos Aires (Argentina); Shay, M. A.; Matthaeus, W. H. [Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Cassak, P. A. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)

2012-09-15T23:59:59.000Z

114

TWO-DIMENSIONAL POLYNOMIAL PHASE SIGNALS: PARAMETER ESTIMATION AND BOUNDS  

E-Print Network [OSTI]

, the problem of modeling and analyzing Synthetic Aperture Radar (SAR) data, and in particular Interferometric SAR (INSAR) images, involves the analysis of complex valued 2-D non-homogeneous signals. Perspective such as camera calibration and the computation of shape from texture. Existing solutions to problems where

Francos, Joseph M.

115

Iso-topological relaxation, coherent structures, and Gaussian turbulence in two dimensional magnetohydrodynamics  

E-Print Network [OSTI]

The long-time relaxation of ideal two dimensional magnetohydrodynamic turbulence subject to the conservation of two infinite families of constants of motion---the magnetic and the "cross" topology invariants--is examined. The analysis of the Gibbs ensemble, where all integrals of motion are respected, predicts the initial state to evolve into an equilibrium, stable coherent structure (the most probable state) and decaying Gaussian turbulence (fluctuations) with a vanishing, but always positive temperature. The non-dissipative turbulence decay is accompanied by decrease in both the amplitude and the length scale of the fluctuations, so that the fluctuation energy remains finite. The coherent structure represents a set of singular magnetic islands with plasma flow whose magnetic topology is identical to that of the initial state, while the energy and the cross topology invariants are shared between the coherent structure and the Gaussian turbulence. These conservation laws suggest the variational principle of iso-topological relaxation which allows us to predict the appearance of the final state from a given initial state. For a generic initial condition having X points in the magnetic field, the coherent structure has universal types of singularities: current sheets terminating at Y points. These structures, which are similar to those resulting from the 2D relaxation of magnetic field frozen into an ideally conducting viscous fluid, are observed in the numerical experiment of Biskamp and Welter. The Gibbs ensemble method developed in this work admits extension to other Hamiltonian systems with invariants not higher than quadratic in the highest-order-derivative variables. The turbulence in two dimensional Euler fluid is of a different nature: there the coherent structures are also formed, but the fluctuations about these structures are non-Gaussian.

M. B. Isichenko; A. V. Gruzinov

1996-09-06T23:59:59.000Z

116

Quantum Process Tomography by 2D Fluorescence Spectroscopy  

E-Print Network [OSTI]

Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement and signal-to-noise ratio ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter $\\Gamma$ of the doubly-excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.

Leonardo A. Pachon; Andrew H. Marcus; Alan Aspuru-Guzik

2015-02-09T23:59:59.000Z

117

Quantum Process Tomography by 2D Fluorescence Spectroscopy  

E-Print Network [OSTI]

Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement and signal-to-noise ratio ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter $\\Gamma$ of the doubly-excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.

Pachon, Leonardo A; Aspuru-Guzik, Alan

2015-01-01T23:59:59.000Z

118

Two dimensional metallic photonic crystals for light trapping and anti-reflective coatings in thermophotovoltaic applications  

SciTech Connect (OSTI)

We report the development of a front-side contact design for thermophotovoltaics that utilizes metallic photonic crystals (PhCs). While this front-side grid replacement covers more surface area of the semiconductor, a higher percentage of photons is shown to be converted to usable power in the photodiode. This leads to a 30% increase in the short-circuit current of the gallium antimonide thermophotovoltaic cell.

Shemelya, Corey; DeMeo, Dante F.; Vandervelde, Thomas E. [The Renewable Energy and Applied Photonics Laboratories, Electrical and Computer Engineering, Tufts University, Medford, Massachusetts 02155 (United States)

2014-01-13T23:59:59.000Z

119

Method and apparatus for two-dimensional spectroscopy  

DOE Patents [OSTI]

Preferred embodiments of the invention provide for methods and systems of 2D spectroscopy using ultrafast, first light and second light beams and a CCD array detector. A cylindrically-focused second light beam interrogates a target that is optically interactive with a frequency-dispersed excitation (first light) pulse, whereupon the second light beam is frequency-dispersed at right angle orientation to its line of focus, so that the horizontal dimension encodes the spatial location of the second light pulse and the first light frequency, while the vertical dimension encodes the second light frequency. Differential spectra of the first and second light pulses result in a 2D frequency-frequency surface equivalent to double-resonance spectroscopy. Because the first light frequency is spatially encoded in the sample, an entire surface can be acquired in a single interaction of the first and second light pulses.

DeCamp, Matthew F. (Swarthmore, PA); Tokmakoff, Andrei (Lexington, MA)

2010-10-12T23:59:59.000Z

120

2D microwave imaging reflectometer electronics  

SciTech Connect (OSTI)

A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

Spear, A. G.; Domier, C. W., E-mail: cwdomier@ucdavis.edu; Hu, X.; Muscatello, C. M.; Ren, X.; Luhmann, N. C. [Electrical and Computer Engineering, University of California, Davis, California 95616 (United States); Tobias, B. J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2014-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


121

Two-dimensional photochemical model of the troposphere. Master's thesis  

SciTech Connect (OSTI)

An experiment using a time-dependent, two-dimensional photochemical model of the troposphere to model the vertical and zonal distribution of ozone and its precursors is presented. The experiment examines two cases. Case I simulates vertical transport due to diffusion and zonal transport due to advection, with surface emissions of ozone precursors in the center of the model domain representing an urban environment with light wind conditions favorable for the formation of ozone in concentrations greater than 80 parts per billion by volume (ppbv). In Case II, an elevated source of ozone and its precursors is introduced at the upstream boundary in order to investigate the role of advection of these chemical species on ozone concentrations. the first simulation produces surface ozone concentrations greater than 120 ppbv in the air above the urban area, and the second simulation produces an increase of 3 - 10 percent in this region. A comparison of Case I and Case II results shows that enhanced photochemical production of ozone due to the addition of ozone's precursors play an important role in this increase.

Carlson, M.W.

1990-01-01T23:59:59.000Z

122

Dynamic Transitions in a Two Dimensional Associating Lattice Gas Model  

E-Print Network [OSTI]

Using Monte Carlo simulations we investigate some new aspects of the phase diagram and the behavior of the diffusion coefficient in an associating lattice gas (ALG) model on different regions of the phase diagram. The ALG model combines a two dimensional lattice gas where particles interact through a soft core potential and orientational degrees of freedom. The competition between soft core potential and directional attractive forces results in a high density liquid phase, a low density liquid phase, and a gas phase. Besides anomalies in the behavior of the density with the temperature at constant pressure and of the diffusion coefficient with density at constant temperature are also found. The two liquid phases are separated by a coexistence line that ends in a bicritical point. The low density liquid phase is separated from the gas phase by a coexistence line that ends in tricritical point. The bicritical and tricritical points are linked by a critical $\\lambda$-line. The high density liquid phase and the fluid phases are separated by a second $\\tau$ critical line. We then investigate how the diffusion coefficient behaves on different regions of the chemical potential-temperature phase diagram. We find that diffusivity undergoes two types of dynamic transitions: a fragile-to-strong trans ition when the critical $\\lambda$-line is crossed by decreasing the temperature at a constant chemical potential; and a strong-to-strong transition when the $\\tau$-critical line is crossed by decreasing the temperature at a constant chemical potential.

Marcia M. Szortyka; Vera Henriques; Mauricio Girardi; Marcia C. Barbosa

2009-02-10T23:59:59.000Z

123

Kolmogorov flow in two dimensional strongly coupled dusty plasma  

SciTech Connect (OSTI)

Undriven, incompressible Kolmogorov flow in two dimensional doubly periodic strongly coupled dusty plasma is modelled using generalised hydrodynamics, both in linear and nonlinear regime. A complete stability diagram is obtained for low Reynolds numbers R and for a range of viscoelastic relaxation time ?{sub m} [0?

Gupta, Akanksha; Ganesh, R., E-mail: ganesh@ipr.res.in; Joy, Ashwin [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 382 428 (India)

2014-07-15T23:59:59.000Z

124

Electrically tunable lasing from a dye-doped two-dimensional hexagonal photonic crystal made of holographic polymer-dispersed liquid  

E-Print Network [OSTI]

Electrically tunable lasing from a dye-doped two-dimensional hexagonal photonic crystal made-dependent electrically tunable lasing of transverse electric TE and transverse magnetic TM modes is demonstrated in a dye recently been investigated in one-dimensional 1D dye-doped reflection and transmission gratings,4,5 where

Demir, Hilmi Volkan

125

Optical properties of two-dimensional metamaterial photonic crystals  

SciTech Connect (OSTI)

In the present work, we theoretically study a 2D photonic crystal (PC) comprised by double negative (DNG) metamaterial cylinders, showing that such a system presents a superior light-matter interaction when compared with their single negative (SNG) plasmonic PC counterparts, suggesting a route to enhance the performance of sensors and photovoltaic cells. On the other hand, we have observed that depending on the frequency, the mode symmetry resembles either the case of SNG electric (SNG-E) or SNG magnetic (SNG-M) PC, suggesting that either the electric or magnetic character of the DNG metamaterial dominates in each case.

Mejía-Salazar, J. R. [Departamento de Física, Universidad del Valle, AA 25360, Cali, Colombia and Instituto de Física, UNICAMP, Campinas-SP 13083-859 (Brazil)

2013-12-14T23:59:59.000Z

126

Criterion based Two Dimensional Protein Folding Using Extended GA  

E-Print Network [OSTI]

Abstract — In the dynamite field of biological and protein research, the protein fold recognition for long pattern protein sequences is a great confrontation for many years. With that consideration, this paper contributes to the protein folding research field and presents a novel procedure for mapping appropriate protein structure to its correct 2D fold by a concrete model using swarm intelligence. Moreover, the model incorporates Extended Genetic Algorithm (EGA) with concealed Markov model (CMM) for effectively folding the protein sequences that are having long chain lengths. The protein sequences are preprocessed, classified and then, analyzed with some parameters (criterion) such as fitness, similarity and sequence gaps for optimal formation of protein structures. Fitness correlation is evaluated for the determination of bonding strength of molecules, thereby involves in efficient fold recognition task. Experimental results have shown that the proposed method is more adept in 2D protein folding and outperforms the existing algorithms. Index Terms — classification, CMM, criterion analysis, EGA, protein folding, sequence gaps I.

T. Kalai Chelvi; P. Rangarajan

127

Optical Properties and Wave Propagation in Semiconductor-Based Two-Dimensional Photonic Crystals  

SciTech Connect (OSTI)

This work is a theoretical investigation on the physical properties of semiconductor-based two-dimensional photonic crystals, in particular for what concerns systems embedded in planar dielectric waveguides (GaAs/AlGaAs, GaInAsP/InP heterostructures, and self-standing membranes) or based on macro-porous silicon. The photonic-band structure of photonic crystals and photonic-crystal slabs is numerically computed and the associated light-line problem is discussed, which points to the issue of intrinsic out-of-lane diffraction losses for the photonic bands lying above the light line. The photonic states are then classified by the group theory formalism: each mode is related to an irreducible representation of the corresponding small point group. The optical properties are investigated by means of the scattering matrix method, which numerically implements a variable-angle-reflectance experiment; comparison with experiments is also provided. The analysis of surface reflectance proves the existence of selection rules for coupling an external wave to a certain photonic mode. Such rules can be directly derived from symmetry considerations. Lastly, the control of wave propagation in weak-index contrast photonic-crystal slabs is tackled in view of designing building blocks for photonic integrated circuits. The proposed designs are found to comply with the major requirements of low-loss propagation, high and single-mode transmission. These notions are then collected to model a photonic-crystal combiner for an integrated multi-wavelength-source laser.

Mario Agio

2002-12-31T23:59:59.000Z

128

Probing energy transfer events in the light harvesting complex 2 (LH2) of Rhodobacter sphaeroides with two-dimensional spectroscopy  

SciTech Connect (OSTI)

Excitation energy transfer events in the photosynthetic light harvesting complex 2 (LH2) of Rhodobacter sphaeroides are investigated with polarization controlled two-dimensional electronic spectroscopy. A spectrally broadened pulse allows simultaneous measurement of the energy transfer within and between the two absorption bands at 800 nm and 850 nm. The phased all-parallel polarization two-dimensional spectra resolve the initial events of energy transfer by separating the intra-band and inter-band relaxation processes across the two-dimensional map. The internal dynamics of the 800 nm region of the spectra are resolved as a cross peak that grows in on an ultrafast time scale, reflecting energy transfer between higher lying excitations of the B850 chromophores into the B800 states. We utilize a polarization sequence designed to highlight the initial excited state dynamics which uncovers an ultrafast transfer component between the two bands that was not observed in the all-parallel polarization data. We attribute the ultrafast transfer component to energy transfer from higher energy exciton states to lower energy states of the strongly coupled B850 chromophores. Connecting the spectroscopic signature to the molecular structure, we reveal multiple relaxation pathways including a cyclic transfer of energy between the two rings of the complex.

Fidler, Andrew F.; Singh, Ved P.; Engel, Gregory S. [Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)] [Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Long, Phillip D.; Dahlberg, Peter D. [Graduate Program in the Biophysical Sciences, The University of Chicago, Chicago, Illinois 60637 (United States)] [Graduate Program in the Biophysical Sciences, The University of Chicago, Chicago, Illinois 60637 (United States)

2013-10-21T23:59:59.000Z

129

Refractory two-dimensional hole gas on hydrogenated diamond surface  

SciTech Connect (OSTI)

Use of two-dimensional hole gas (2DHG), induced on a hydrogenated diamond surface, is a solution to overcoming one of demerits of diamond, i.e., deep energy levels of impurities. This 2DHG is affected by its environment and accordingly needs a passivation film to get a stable device operation especially at high temperature. In response to this requirement, we achieved the high-reliability passivation forming an Al{sub 2}O{sub 3} film on the diamond surface using an atomic-layer-deposition (ALD) method with an H{sub 2}O oxidant at 450 Degree-Sign C. The 2DHG thus protected survived air annealing at 550 Degree-Sign C for an hour, establishing a stable high-temperature operation of 2DHG devices in air. In part, this achievement is based on high stability of C-H bonds up to 870 Degree-Sign C in vacuum and above 450 Degree-Sign C in an H{sub 2}O-containing environment as in the ALD. Chemically, this stability is supported by the fact that both the thermal decomposition of C-H bonds and reaction between C-H bonds and H{sub 2}O are endothermic processes. It makes a stark contrast to the instability of Si-H bonds, which decompose even at room temperature being exposed to atomic hydrogen. In this respect, the diamond 2DHG devices are also promising as power devices expectedly being free from many instability phenomena, such as hot carrier effect and negative-bias temperature instability, associated with Si devices. As to adsorbate, which is the other prerequisite for 2DHG, it desorbed in vacuum below 250 Degree-Sign C, and accordingly some new adsorbates should have adsorbed during the ALD at 450 Degree-Sign C. As a clue to this question, we certainly confirmed that some adsorbates, other than those at room temperature, adsorbed in air above 100 Degree-Sign C and remained at least up to 290 Degree-Sign C. The identification of these adsorbates is open for further investigation.

Hiraiwa, Atsushi [Institute for Nanoscience and Nanotechnology, Waseda University, 513 Waseda-tsurumaki, Shinjuku, Tokyo 162-0041 (Japan); Daicho, Akira; Kurihara, Shinichiro; Yokoyama, Yuki; Kawarada, Hiroshi [Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan)

2012-12-15T23:59:59.000Z

130

Results from laboratory tests of the two-dimensional Time-Encoded Imaging System.  

SciTech Connect (OSTI)

A series of laboratory experiments were undertaken to demonstrate the feasibility of two dimensional time-encoded imaging. A prototype two-dimensional time encoded imaging system was designed and constructed. Results from imaging measurements of single and multiple point sources as well as extended source distributions are presented. Time encoded imaging has proven to be a simple method for achieving high resolution two-dimensional imaging with potential to be used in future arms control and treaty verification applications.

Marleau, Peter; Brennan, James S.; Brubaker, Erik; Gerling, Mark D; Le Galloudec, Nathalie Joelle

2014-09-01T23:59:59.000Z

131

E-Print Network 3.0 - automated two-dimensional protein Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

; Environmental Sciences and Ecology 2 Protein Array Technology: The Tool to Bridge Genomics and Proteomics Summary: cardiomyopathy by two- dimensional gel electrophoresis and...

132

E-Print Network 3.0 - axisymmetric two-dimensional computation...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

- persion relation is derived from two-dimensional eigenproblems based on the velocity fields prevailing... to display the following behaviour at moderate Reynolds numbers: the...

133

Signatures of the protein folding pathway in two-dimensional ultraviolet spectroscopy  

E-Print Network [OSTI]

2) Dobson, C. M. Protein Folding and Misfolding. Naturethe Complexity of Protein Folding. Curr. Opin. Struct. Biol.Signatures of the Protein Folding Pathway in Two-Dimensional

Jiang, J; Lai, Z; Wang, J; Mukamel, S

2014-01-01T23:59:59.000Z

134

Two-dimensional elastic wave propagation in a duraluminum sheet  

E-Print Network [OSTI]

MENTAL PROCEDURE Experimental Design Data Acquisition Data Correction III. DATA PROCESSING 12 12 12 15 16 Wiener Filter Theory Construction of Desired. Wavelet 23 25 Wiener Filter Results 27 Bandpass Filter IV. TRAVELTIME ANALYSIS Wave... perpendicular to strike 2, Duraluminum model used in experiments 1 and 2 Relations between the Rayleigh-, P-, and S-wave velocities in an infinite medium for Poisson's ratio, o-, ranging from 0. 0 to 0. 5 Square root of energy ratios for reflected P- and S-waves...

Cefola, David Paul

1982-01-01T23:59:59.000Z

135

An Efficient Genetic Algorithm for Predicting Protein Tertiary Structures in the 2D HP Model  

E-Print Network [OSTI]

, predicting its tertiary structure is known as the protein folding problem. This problem has been widely genetic algo- rithm for the protein folding problem under the HP model in the two-dimensional square Genetic Algorithm, Protein Folding Problem, 2D HP Model 1. INTRODUCTION Amino acids are the building

Istrail, Sorin

136

Plateau border bulimia transition: discontinuities expected in three simple experiments on 2D liquid foams  

E-Print Network [OSTI]

be observable. II. 2D GLASS-GLASS FOAM GEOMETRICAL VADEMECUM In the present section, we shall provide a geometri- cal description and some corresponding results for two- dimensional foams squeezed between two glass liquid foams Pierre Rognon, Fran¸cois Molino, and Cyprien Gay Centre de Recherche Paul Pascal, CNRS, UPR

Paris-Sud XI, Université de

137

Plateau border bulimia transition: discontinuities expected in three simple experiments on 2D liquid foams  

E-Print Network [OSTI]

be observable. II. 2D GLASS-GLASS FOAM GEOMETRICAL VADEMECUM In the present section, we shall provide a geometri- cal description and some corresponding results for two- dimensional foams squeezed between two glass liquid foams Pierre Rognon, Fran#24;cois Molino, and Cyprien Gay #3; Centre de Recherche Paul Pascal

Recanati, Catherine

138

Simultaneous sensing of light and sound velocities of fluids in a two-dimensional phoXonic crystal with defects  

SciTech Connect (OSTI)

We theoretically investigate the potentiality of dual phononic-photonic (the so-called phoxonic) crystals for liquid sensing applications. We study the transmission through a two-dimensional (2D) crystal made of infinite cylindrical holes in a silicon substrate, where one row of holes oriented perpendicular to the propagation direction is filled with a liquid. The infiltrated holes may have a different radius than the regular holes. We show, in the defect structure, the existence of well-defined features (peaks or dips) in the transmission spectra of acoustic and optical waves and estimate their sensitivity to the sound and light velocity of the analyte. Some of the geometrical requirements behave in opposite directions when searching for an efficient sensing of either sound or light velocities. Hence, a compromise in the choice of the parameters may become necessary in making the phoxonic sensor.

Amoudache, Samira [Institut d'Electronique, de Microélectronique et de Nanotechnologie, Université de Lille 1, 59655 Villeneuve d'Ascq (France); Laboratoire de Physique et Chimie Quantique, Université Mouloud Mammeri, B.P. 17 RP, 15000 Tizi-Ouzou (Algeria); Pennec, Yan, E-mail: yan.pennec@univ-lille1.fr; Djafari Rouhani, Bahram [Institut d'Electronique, de Microélectronique et de Nanotechnologie, Université de Lille 1, 59655 Villeneuve d'Ascq (France); Khater, Antoine [Institut des Molécules et Matériaux du Mans UMR 6283 CNRS, Université du Maine, 72085 Le Mans (France); Lucklum, Ralf [Institute of Micro and Sensor Systems (IMOS), Otto-von-Guericke-University, Magdeburg (Germany); Tigrine, Rachid [Laboratoire de Physique et Chimie Quantique, Université Mouloud Mammeri, B.P. 17 RP, 15000 Tizi-Ouzou (Algeria)

2014-04-07T23:59:59.000Z

139

PHYSICAL REVIEW E 87, 012142 (2013) Weighting of topologically different interactions in a model of two-dimensional polymer collapse  

E-Print Network [OSTI]

of two-dimensional polymer collapse Andrea Bedini* and Aleksander L. Owczarek Department of Mathematics

Prellberg, Thomas

140

Two-Dimensional NMR Spectroscopy Elimination of Zero-Quantum Interference in  

E-Print Network [OSTI]

the sample is large enough, the net result will be cancelation of the zero-quantum coherence. A simpleTwo-Dimensional NMR Spectroscopy Elimination of Zero-Quantum Interference in Two-Dimensional NMR and homonuclear zero-quantum coherence, which is invariably present. The zero-quantum coherence gives rise to anti

Keeler, James

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Instability of two-dimensional graphene: Breaking sp2 bonds with soft x rays  

E-Print Network [OSTI]

Instability of two-dimensional graphene: Breaking sp2 bonds with soft x rays S. Y. Zhou,1,2 Ç. Ö the stability of various kinds of graphene samples under soft x-ray irradiation. Our results show that in single-layer exfoliated graphene a closer analog to two-dimensional material , the in-plane carbon- carbon bonds

Zettl, Alex

142

Sinc Approximation of the Heat Distribution on the Boundary of a Two-Dimensional Finite Slab  

E-Print Network [OSTI]

We consider the two-dimensional problem of recovering globally in time the heat distribution on the surface of a layer inside of a heat conducting body from two interior temperature measurements. The problem is ill-posed. The approximation function is represented by a two-dimensional Sinc series and the error estimate is given.

Dinh, Alain Pham Ngoc; Trong, Dang Duc

2007-01-01T23:59:59.000Z

143

Two-Dimensional Infrared Correlation Spectroscopy Study of the Aggregation of Cytochrome c in the Presence  

E-Print Network [OSTI]

Two-Dimensional Infrared Correlation Spectroscopy Study of the Aggregation of Cytochrome c´ cules, Universite´ Laval, Que´ bec, Que´ bec, Canada G1K 7P4 ABSTRACT Two-dimensional infrared-step aggregation process. Finally, the results obtained during the heating period clearly indicate that before

Pezolet, Michel

144

Unimodal Maps as Boundary-Restrictions of Two-Dimensional Full-Folding Maps  

E-Print Network [OSTI]

Unimodal Maps as Boundary-Restrictions of Two-Dimensional Full-Folding Maps Hideki TSUIKI tsuiki-75-753-6744, Fax:+81-75-753-6694 Abstract It is shown that every unimodal map is realized as a restriction of a simple map defined on the unit disc to a part of its boundary. Our two-dimensional map is called a full

Tsuiki, Hideki

145

Sedimenting discs in a two-dimensional foam I. T. Davies, S. J. Cox  

E-Print Network [OSTI]

-dimensional foams can be thought of as a monolayer of bubbles squeezed between two glass plates. We choose to probeSedimenting discs in a two-dimensional foam I. T. Davies, S. J. Cox Institute of Mathematics in a dry two-dimensional, monodisperse foam is studied. This, a variation of the classical Stokes

Cox, Simon

146

Two-bubble instabilities in quasi-two-dimensional and S.J. COX 2  

E-Print Network [OSTI]

in which, instead of a glass plate, the foam was bounded below by the surface of a liquid poolTwo-bubble instabilities in quasi-two-dimensional foams M.F. VAZ 1 and S.J. COX 2 1 Instituto de Ci of the experimental set-up on the structure and rheology of two- dimensional foams. We perform the same experiment

Cox, Simon

147

Flow in linearly sheared two dimensional foams: from bubble to bulk scale  

E-Print Network [OSTI]

We probe the flow of two dimensional foams, consisting of a monolayer of bubbles sandwiched between a liquid bath and glass plate, as a function of driving rate, packing fraction and degree of disorder. First, we find that bidisperse, disordered foams exhibit strongly rate dependent and inhomogeneous (shear banded) velocity profiles, while monodisperse, ordered foams are also shear banded, but essentially rate independent. Second, we introduce a simple model based on balancing the averaged drag forces between the bubbles and the top plate and the averaged bubble-bubble drag forces. This model captures the observed rate dependent flows, and the rate independent flows. Third, we perform independent rheological measurements, both for ordered and disordered systems, and find these to be fully consistent with the scaling forms of the drag forces assumed in the simple model, and we see that disorder modifies the scaling. Fourth, we vary the packing fraction $\\phi$ of the foam over a substantial range, and find that the flow profiles become increasingly shear banded when the foam is made wetter. Surprisingly, our model describes flow profiles and rate dependence over the whole range of packing fractions with the same power law exponents -- only a dimensionless number $k$ which measures the ratio of the pre-factors of the viscous drag laws is seen to vary with packing fraction. We find that $k \\sim (\\phi-\\phi_c)^{-1}$, where $\\phi_c \\approx 0.84$, corresponding to the 2d jamming density, and suggest that this scaling follows from the geometry of the deformed facets between bubbles in contact. Overall, our work suggests a route to rationalize aspects of the ubiquitous Herschel-Bulkley (power law) rheology observed in a wide range of disordered materials.

Gijs Katgert; Andrzej Latka; Matthias E. Möbius; Martin van Hecke

2009-03-31T23:59:59.000Z

148

3D rotational diffusion microrheology using 2D video microscopy  

E-Print Network [OSTI]

We propose a simple way to perform three-dimensional (3D) rotational microrheology using two-dimensional (2D) video microscopy. The 3D rotational brownian motion of micrometric wires in a viscous fluid is deduced from their projection on the focal plane of an optical microscope objective. The rotational diffusion coefficient of the wires of length between 1-100 \\mu m is extracted, as well as their diameter distribution in good agreement with electron microscopy measurements. This is a promising way to characterize soft visco-elastic materials, and probe the dimensions of anisotropic objects.

Rémy Colin; Minhao Yan; Loudjy Chevry; Jean-François Berret; Bérengère Abou

2012-01-05T23:59:59.000Z

149

Exact solutions for the 2d one component plasma  

E-Print Network [OSTI]

The 2d one component gas of pointlike charges in a uniform neutralizing background interacting with a logarithmic potential is a common model for plasmas. In its classical equilibrium statistics at fixed temperature (canonical ensemble) it is formally related to certain types of random matrices with Gaussian distribution and complex eigenvalues. In this paper, I present an exact integration of this ensemble for $N$ such particles (or alternatively $N\\times N$ matrices) for all even non-negative temperatures, a significant open problem in statistical physics for several decades. I achieve this exact integration via an exact integration of a related ensemble, the two-dimensional Selberg integral.

Timothy D. Andersen

2013-02-13T23:59:59.000Z

150

2D electron density profile measurement in tokamak by laser-accelerated ion-beam probe  

SciTech Connect (OSTI)

A new concept of Heavy Ion Beam Probe (HIBP) diagnostic has been proposed, of which the key is to replace the electrostatic accelerator of traditional HIBP by a laser-driven ion accelerator. Due to the large energy spread of ions, the laser-accelerated HIBP can measure the two-dimensional (2D) electron density profile of tokamak plasma. In a preliminary simulation, a 2D density profile was reconstructed with a spatial resolution of about 2 cm, and with the error below 15% in the core region. Diagnostics of 2D density fluctuation is also discussed.

Chen, Y. H.; Yang, X. Y.; Lin, C., E-mail: linchen0812@pku.edu.cn, E-mail: cjxiao@pku.edu.cn; Wang, X. G.; Xiao, C. J., E-mail: linchen0812@pku.edu.cn, E-mail: cjxiao@pku.edu.cn [State Key Lab of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Wang, L. [Institute of Physics, Chinese Academy of Sciences, P. O. Box 603, Beijing 100190 (China); Xu, M. [Center for Fusion Science of Southwestern Institute of Physics, P. O. Box 432, Chengdu 610041 (China)

2014-11-15T23:59:59.000Z

151

Sputter deposition of multilayer thermoelectric films: An approach to the fabrication of two-dimensional quantum wells  

SciTech Connect (OSTI)

The relative efficiency of a thermoelectric material is measured in terms of a dimensionless figure of merit, ZT. Though all known thermoelectric materials are believed to have ZT{le}1, recent theoretical results predict that thermoelectric devices fabricated as two-dimensional quantum wells (2D QWs) or onedimensional (1D) quantum wires could have ZT{ge}3. Multilayers with the dimensions of 2D QWs have been synthesized by alternately sputtering Bi{sub 0.9}Sb{sub 0.1} and PbTe{sub 0.8}Se{sub 0.2} onto a moving single-crystal sapphire substrate from dual magnetrons. These materials have been used to test the thermoelectric quantum-well concept and gain insight into relevant transport mechanisms. If successful, this research could lead to thermoelectric devices that have efficiencies close to that of an ideal Carnot engine. Ultimately, such devices could be used to replace conventional heat engines and mechanical refrigeration systems.

Farmer, J.C.; Barbee, T.W. Jr.; Chapline, G.C. Jr.; Foreman, R.J.; Summers, L.J. [Lawrence Livermore National Lab., CA (United States); Dresselhaus, M.S.; Hicks, L.D. [Massachusetts Institute of Technology, Boston, MA (United States). Dept. of Physics

1994-07-01T23:59:59.000Z

152

Excitation of two-dimensional plasma wakefields by trains of equidistant particle bunches  

SciTech Connect (OSTI)

Nonlinear effects responsible for elongation of the plasma wave period are numerically studied with the emphasis on two-dimensionality of the wave. The limitation on the wakefield amplitude imposed by detuning of the wave and the driver is found.

Lotov, K. V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)] [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

2013-08-15T23:59:59.000Z

153

Symmetric Two Dimensional Linear Discriminant Analysis (2DLDA) Dijun Luo, Chris Ding, Heng Huang  

E-Print Network [OSTI]

Symmetric Two Dimensional Linear Discriminant Analysis (2DLDA) Dijun Luo, Chris Ding, Heng Huang, heng}@uta.edu Abstract Linear discriminant analysis (LDA) has been success- fully applied into computer

Huang, Heng

154

Three-dimensional and two-dimensional deployment analysis for underwater acoustic sensor networks q  

E-Print Network [OSTI]

Three-dimensional and two-dimensional deployment analysis for underwater acoustic sensor networks q Accepted 23 July 2008 Available online 7 August 2008 Keywords: Underwater acoustic sensor networks data collection, pollution monitoring, offshore exploration, disaster prevention, assisted navigation

Pompili, Dario

155

An experimental study of unsteady separation in a two-dimensional flow  

E-Print Network [OSTI]

An experimental study of flow separation in an incompressible two-dimensional unsteady flow was undertaken with the aim of validating recently developed flow separation criteria, which are based on kinematic principles. ...

Coral Pinto, Raul Javier

2005-01-01T23:59:59.000Z

156

Electronic and magnetic properties of Fe and Mn doped two dimensional hexagonal germanium sheets  

SciTech Connect (OSTI)

Using first principles density functional theory calculations, the present paper reports systematic total energy calculations of the electronic properties such as density of states and magnetic moment of pristine and iron and manganese doped two dimensional hexagonal germanium sheets.

Soni, Himadri R., E-mail: himadri.soni@gmail.com; Jha, Prafulla K., E-mail: himadri.soni@gmail.com [Department of Physics, Maharaja Krishnakumarsinhji Bhavnagar University, Bhavnagar-364001 (India)

2014-04-24T23:59:59.000Z

157

Modeling of acoustic wave scattering from a two-dimensional fracture  

E-Print Network [OSTI]

In this paper, we model the acoustic scattering from a two dimensional fracture that is simulated by two different physical models. We calculate the scattering from the fractures with different properties based on these ...

Wang, Ping

2010-01-01T23:59:59.000Z

158

Mechanical fault interaction within the Los Angeles Basin: A two-dimensional analysis using mechanical efficiency  

E-Print Network [OSTI]

Mechanical fault interaction within the Los Angeles Basin: A two-dimensional analysis using mechanical efficiency Michele L. Cooke Geosciences Department, University of Massachusetts-Amherst, Amherst July 2002. [1] Mechanical models examine deformation within eight different structural cross sections

Cooke, Michele

159

THESIS FOR THE DEGREE OF LICENTIATE OF PHILOSOPHY On the two-dimensional Pauli operator  

E-Print Network [OSTI]

THESIS FOR THE DEGREE OF LICENTIATE OF PHILOSOPHY On the two-dimensional Pauli operator of Aharonov-Bohm solenoids Mikael Persson Abstract This licentiate thesis consists of two papers comparing

Patriksson, Michael

160

E-Print Network 3.0 - angle-resolved two-dimensional mapping...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Rettig... in an energy- and angle-resolved manner. To achieve this, a field free drift tube with an acceptance angle... of 22 is combined with two-dimensional position-sensitive...

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

An investigation of fixed separation in quasi-periodic and aperiodic, unsteady, two-dimensional flows  

E-Print Network [OSTI]

This study asses the kinematic theory of fixed separation in unsteady, two-dimensional flows that has been proposed by Haller (2004). Experimental investigations were conducted that utilized the rotor-oscillator flow to ...

Helu, Moneer Mohammad

2007-01-01T23:59:59.000Z

162

Two dimensional finite element analysis of homogenization and failure in plain weave textile composites  

E-Print Network [OSTI]

TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF HOMOGENIZATION AND FAILURE IN PLAIN WEAVE TEXTILE COMPOSITES A Thesis by VEERARAGHAVA GOPAL KONDAGUNTA Submitted to the Office of Graduate Studies of Texas ARM University In partial fulffllment... of the requirements for the degree of MASTER OF SCIENCE August 1993 Major Subject: Aerospace Engineering TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF HOMOGENIZATION AND FAILURE IN PLAIN WEAVE TEXTILE COMPOSITES A Thesis by VEERARAGHAVA GOPAL KONDAGUNTA...

Kondagunta, Veeraraghava Gopal

1993-01-01T23:59:59.000Z

163

Evaluation of new techniques for two dimensional finite element analysis of woven composites  

E-Print Network [OSTI]

EVALUATION OF NEW TECHNIQUES FOR TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF WOVEN COMPOSITES A Thesis by SITARAM CHOWDARY GUNDAPANENI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE DECEMBER 1992 Major Subject: Aerospace Engineering EVALUATION OF NEW TECHNIQUES FOR TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF WOVEN COMPOSITES A Thesis by SITARAM CHOWDARY GUNDAPANENI Approved...

Gundapaneni, Sitaram Chowdary

1992-01-01T23:59:59.000Z

164

MESH2D GRID GENERATOR DESIGN AND USE  

SciTech Connect (OSTI)

Mesh2d is a Fortran90 program designed to generate two-dimensional structured grids of the form [x(i),y(i,j)] where [x,y] are grid coordinates identified by indices (i,j). The x(i) coordinates alone can be used to specify a one-dimensional grid. Because the x-coordinates vary only with the i index, a two-dimensional grid is composed in part of straight vertical lines. However, the nominally horizontal y(i,j{sub 0}) coordinates along index i are permitted to undulate or otherwise vary. Mesh2d also assigns an integer material type to each grid cell, mtyp(i,j), in a user-specified manner. The complete grid is specified through three separate input files defining the x(i), y(i,j), and mtyp(i,j) variations. The overall mesh is constructed from grid zones that are typically then subdivided into a collection of smaller grid cells. The grid zones usually correspond to distinct materials or larger-scale geometric shapes. The structured grid zones are identified through uppercase indices (I,J). Subdivision of zonal regions into grid cells can be done uniformly, or nonuniformly using either a polynomial or geometric skewing algorithm. Grid cells may be concentrated backward, forward, or toward both ends. Figure 1 illustrates the above concepts in the context of a simple four zone grid.

Flach, G.; Smith, F.

2012-01-20T23:59:59.000Z

165

Discriminating trpzip2 and trpzip4 peptides’ folding landscape using the two-dimensional infrared spectroscopy: A simulation study  

SciTech Connect (OSTI)

We analyzed, based on the theoretical spectroscopic modeling, how the differences in the folding landscapes of two ?-hairpin peptides trpzip2 and trpzip4 are reflected in their thermal unfolding infrared measurements. The isotope-edited equilibrium FTIR and two dimensional infrared spectra of the two peptides were calculated, using the nonlinear exciton propagation method, at a series of temperatures. The spectra calculations were based on the configuration distributions generated using the GB{sup OBC} implicit solvent MD simulation and the integrated tempering sampling technique. Conformational analysis revealed the different local thermal stabilities for these two peptides, which suggested the different folding landscapes. Our study further suggested that the ellipticities of the isotope peaks in the coherent IR signals are more sensitive to these local stability differences compared with other spectral features such as the peak intensities. Our technique can thus be combined with the relevant experimental measurements to achieve a better understanding of the peptide folding behaviors.

Wu, Tianmin; Zhang, Ruiting; Li, Huanhuan; Zhuang, Wei, E-mail: wzhuang@dicp.ac.cn, E-mail: lijiangy@pku.edu.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China)] [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning (China); Yang, Lijiang, E-mail: wzhuang@dicp.ac.cn, E-mail: lijiangy@pku.edu.cn [College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871 (China)] [College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871 (China)

2014-02-07T23:59:59.000Z

166

TOPAZ2D heat transfer code users manual and thermal property data base  

SciTech Connect (OSTI)

TOPAZ2D is a two dimensional implicit finite element computer code for heat transfer analysis. This user's manual provides information on the structure of a TOPAZ2D input file. Also included is a material thermal property data base. This manual is supplemented with The TOPAZ2D Theoretical Manual and the TOPAZ2D Verification Manual. TOPAZ2D has been implemented on the CRAY, SUN, and VAX computers. TOPAZ2D can be used to solve for the steady state or transient temperature field on two dimensional planar or axisymmetric geometries. Material properties may be temperature dependent and either isotropic or orthotropic. A variety of time and temperature dependent boundary conditions can be specified including temperature, flux, convection, and radiation. Time or temperature dependent internal heat generation can be defined locally be element or globally by material. TOPAZ2D can solve problems of diffuse and specular band radiation in an enclosure coupled with conduction in material surrounding the enclosure. Additional features include thermally controlled reactive chemical mixtures, thermal contact resistance across an interface, bulk fluid flow, phase change, and energy balances. Thermal stresses can be calculated using the solid mechanics code NIKE2D which reads the temperature state data calculated by TOPAZ2D. A three dimensional version of the code, TOPAZ3D is available. The material thermal property data base, Chapter 4, included in this manual was originally published in 1969 by Art Edwards for use with his TRUMP finite difference heat transfer code. The format of the data has been altered to be compatible with TOPAZ2D. Bob Bailey is responsible for adding the high explosive thermal property data.

Shapiro, A.B.; Edwards, A.L.

1990-05-01T23:59:59.000Z

167

Two-dimensional modeling of sodium boiling transients in simulated LMFBR fuel bundles  

SciTech Connect (OSTI)

A two-dimensional code for analysis of sodium boiling in LMFBR fuel assemblies has been developed at ORNL. This code, THORAX, has been used to analyze tests in 19- and 61-pin electrically-heated, simulated LMFBR fuel assemblies in the THORS facility. THORAX has simulated well the transient growth of the two-dimensional boiling region and the resulting static flow instability leading to dryout. Extrapolation of results to a full size fuel pin bundle shows that two-dimensional effects are reduced but still significant. The code will be extended to include a loop model in support of forthcoming tests in the THORS-SHRS Assembly 1 loop, which will include two parallel 19-pin simulated driver bundles.

Rose, S.D.; Dearing, J.F; Carbajo, J.J.; Levin, A.E.; Montgomery, B.H.; Wantland, J.L.

1982-01-01T23:59:59.000Z

168

Stability analysis for two-dimensional ion-acoustic waves in quantum plasmas  

SciTech Connect (OSTI)

The quantum hydrodynamic model is applied to two-dimensional ion-acoustic waves in quantum plasmas. The two-dimensional quantum hydrodynamic model is used to obtain a deformed Kortewegde Vries (dKdV) equation by reductive perturbation method. By using the solution of auxiliary ordinary equations, a extended direct algebraic method is described to construct the exact solutions for nonlinear quantum dKdV equation. The present results are describing the generation and evolution of such waves, their interactions, and their stability.

Seadawy, A. R., E-mail: Aly742001@yahoo.com [Mathematics Department, Faculty of Science, Taibah University, Al-Ula (Saudi Arabia); Mathematics Department, Faculty of Science, Beni-Suef University (Egypt)

2014-05-15T23:59:59.000Z

169

System for generating two-dimensional masks from a three-dimensional model using topological analysis  

DOE Patents [OSTI]

A method of generating two-dimensional masks from a three-dimensional model comprises providing a three-dimensional model representing a micro-electro-mechanical structure for manufacture and a description of process mask requirements, reducing the three-dimensional model to a topological description of unique cross sections, and selecting candidate masks from the unique cross sections and the cross section topology. The method further can comprise reconciling the candidate masks based on the process mask requirements description to produce two-dimensional process masks.

Schiek, Richard (Albuquerque, NM)

2006-06-20T23:59:59.000Z

170

Crossed modules of Hopf algebras and of associative algebras and two-dimensional holonomy  

E-Print Network [OSTI]

After a thorough treatment of all algebraic structures involved, we address two dimensional holonomy operators with values in crossed modules of Hopf algebras and in crossed modules of associative algebras (called here crossed modules of bare algebras.) In particular, we will consider two general formulations of the two-dimensional holonomy of a (fully primitive) Hopf 2-connection (exact and blur), the first being multiplicative the second being additive, proving that they coincide in a certain natural quotient (defining what we called the fuzzy holonomy of a fully primitive Hopf 2-connection).

Martins, Joao Faria

2015-01-01T23:59:59.000Z

171

A New Proof on Net Upscale Energy Cascade in 2D and QG Turbulence  

E-Print Network [OSTI]

A general proof that more energy flows upscale than downscale in two-dimensional (2D) turbulence and barotropic quasi-geostrophic (QG) turbulence is given. A proof is also given that in Surface QG turbulence, the reverse is true. Though some of these results are known in restricted cases, the proofs given here are pedagogically simpler, require fewer assumptions and apply to both forced and unforced cases.

Eleftherios Gkioulekas; Ka Kit Tung

2006-09-30T23:59:59.000Z

172

ccsd00001226 Ultracold atoms con ned in rf-induced two-dimensional trapping potentials  

E-Print Network [OSTI]

into this trap, starting either from thermal samples or Bose{Einstein condensates. In the latter case, technical along one direction to produce a two-dimensional atomic gas. We transferred ultracold atoms.50.Vk, 03.75.-b, 32.80.Pj It is well known that Bose{Einstein condensation (BEC) of homogeneous gases

173

Solving a Two-Dimensional Elliptic Model Problem with the Conjugate Gradient Method Using  

E-Print Network [OSTI]

Solving a Two-Dimensional Elliptic Model Problem with the Conjugate Gradient Method Using Matrix Preconditioned Conjugate Gradient method in Matlab can be optimized in terms of wall clock time and, more-free Preconditioned Conjugate Gradient method. This superior algorithm computes the same numerical solution to our

Gobbert, Matthias K.

174

Warranty and Fair Pricing for Used Items in Two-Dimensional Boyan Dimitrov  

E-Print Network [OSTI]

and is valid during some limited future time of use, or until some future mileage is driven, whichever comesWarranty and Fair Pricing for Used Items in Two-Dimensional Life Time Boyan Dimitrov Dept-dimensional life to illustrate how cost characteristics should be fairly assessed. Pricing of used items

Stanchev, Peter

175

Asymptotic Behavior of Energy Solutions to a Two Dimensional Semilinear Problem with Mixed  

E-Print Network [OSTI]

Asymptotic Behavior of Energy Solutions to a Two Dimensional Semilinear Problem with Mixed Boundary with the asymptotic behavior of the energy solutions of the mixed boundary value problem u + up = 0 in u = 0 on 0 School of Mathematics, University of Minnesota Minneapolis, MN 55455 Key words and phrases: Mixed

Ren, Xiaofeng

176

SURFACE TENSION AND DEFORMATIONS OF MEMBRANE STRUCTURES : RELATION TO TWO-DIMENSIONAL PHASE TRANSITIONS  

E-Print Network [OSTI]

1099 SURFACE TENSION AND DEFORMATIONS OF MEMBRANE STRUCTURES : RELATION TO TWO-DIMENSIONAL PHASE les molécules sont en contact avec un réservoir. Dans le premier cas, la tension de surface est nulle tension de surface finie et les fluctuations sont très réduites. Ce résultat est en accord avec des

Boyer, Edmond

177

Physica D 136 (2000) 245265 Dynamics of kinks in two-dimensional hyperbolic models  

E-Print Network [OSTI]

indicative of the tendency of the free energy to decay towards a minimum. In the case of a non-conserved, and non-negative, and f () a real odd function with positive maximum equal to , negative minimum equal. With f () = sin , Eq. (1) is a two-dimensional generalization of the standard model of a large area

Rotstein, Horacio G.

178

Simulation of Two-Dimensional Ultraviolet Spectroscopy of Amyloid Fibrils Darius Abramavicius,  

E-Print Network [OSTI]

diseases. Amyloid fibrils are formed by a wide variety of peptides and proteins and can be distinguishedSimulation of Two-Dimensional Ultraviolet Spectroscopy of Amyloid Fibrils Jun Jiang, Darius, 2010 Revealing the structure and aggregation mechanism of amyloid fibrils is essential

Mukamel, Shaul

179

Simulations of the Two-Dimensional Electronic Spectroscopy of the Photosystem II Reaction Center  

E-Print Network [OSTI]

for spectroscopic study. A purified PSII preparation capable of evolving oxygen consists of so-called BBY particlesSimulations of the Two-Dimensional Electronic Spectroscopy of the Photosystem II Reaction Center K spectroscopy of the Qy band of the D1-D2-Cyt b559 photosystem II reaction center at 77 K. We base

Mukamel, Shaul

180

RANDOM WALK IN RANDOM ENVIRONMENT IN A TWO-DIMENSIONAL STRATIFIED MEDIUM WITH ORIENTATIONS  

E-Print Network [OSTI]

RANDOM WALK IN RANDOM ENVIRONMENT IN A TWO-DIMENSIONAL STRATIFIED MEDIUM WITH ORIENTATIONS ALEXIS walk in random environment, random walk in random scenery, functional limit theorem, transience. This research was supported by the french ANR project MEMEMO2. 1 #12;RWRE IN A STRATIFIED ORIENTED MEDIUM 2 Our

Pène, Françoise

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

RANDOM WALK IN RANDOM ENVIRONMENT IN A TWO-DIMENSIONAL STRATIFIED MEDIUM WITH ORIENTATIONS  

E-Print Network [OSTI]

RANDOM WALK IN RANDOM ENVIRONMENT IN A TWO-DIMENSIONAL STRATIFIED MEDIUM WITH ORIENTATIONS ALEXIS oriented lattices, random walk in random environment, random walk in random scenery, functional limit-00634636,version2-24Nov2012 #12;RWRE IN A STRATIFIED ORIENTED MEDIUM 2 We denote by E and E

Paris-Sud XI, Université de

182

TWO-DIMENSIONAL SIMULATIONS OF VALVELESS PUMPING USING THE IMMERSED BOUNDARY METHOD  

E-Print Network [OSTI]

TWO-DIMENSIONAL SIMULATIONS OF VALVELESS PUMPING USING THE IMMERSED BOUNDARY METHOD EUNOK JUNG. 1, pp. 19­45 Abstract. Flow driven by pumping without valves is examined, motivated by biomedical words. valveless pumping, immersed boundary method, frequency, CPR AMS subject classifications. 76D05

Peskin, Charles S.

183

Discrete-ordinates solution of short-pulsed laser transport in two-dimensional turbid media  

E-Print Network [OSTI]

of the hyperbolic transient radiative-transport equation are not known. Ku- mar et al.4 considered the solution-pulsed laser transport is transient radiative-transfer theory. Complete an- alytical solutionsDiscrete-ordinates solution of short-pulsed laser transport in two-dimensional turbid media

Guo, Zhixiong "James"

184

Edge-spin accumulation in semiconductor two-dimensional hole gases RID E-5081-2010  

E-Print Network [OSTI]

The controlled generation of localized spin densities is a key enabler of semiconductor spintronics In this work, we study spin Hall effect induced edge-spin accumulation in a two-dimensional hole gas with strong spin orbit interactions. We argue...

Nomura, K.; Wunderlich, J.; Sinova, Jairo; Kaestner, B.; MacDonald, AH; Jungwirth, T.

2005-01-01T23:59:59.000Z

185

Surface-Skimming Stoneflies and Mayflies: The Taxonomic and Mechanical Diversity of Two-Dimensional Aerodynamic  

E-Print Network [OSTI]

-Dimensional Aerodynamic Locomotion* James H. Marden Brigid C. O'Donnell Michael A. Thomas Jesse Y. Bye Department be used to accomplish two-dimensional aerodynamic locomotion on the surface of water. Here we extend, horizontal velocity, and the verticality of aerodynamic force production increase as the body orientation

Marden, James

186

Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer in Window Frames  

E-Print Network [OSTI]

1 Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer Arasteh and Dragan Curcija ABSTRACT Accurately analyzing heat transfer in window frame cavities radiation heat-transfer effects.) We examine three representative complex cavity cross-section profiles

187

Nano Res 1 Construction of two-dimensional hydrogen clusters on  

E-Print Network [OSTI]

Nano Res 1 Construction of two-dimensional hydrogen clusters on Au(111) directed by phthalocyanine molecules Kai Yang, Wende Xiao, Liwei Liu, Xiangmin Fei, Hui Chen, Shixuan Du and Hong-Jun Gao () Nano Res. Nano Research DOI 10.1007/s1227401303734 #12;1 TABLE OF CONTENTS (TOC) Construction of Two

Gao, Hongjun

188

Wideband two-dimensional and multiple beam phased arrays and microwave applications using piezoelectric transducers  

E-Print Network [OSTI]

array are designed to span 10 to 35 GHz. In addition, a 4??4 two-dimensional antenna array is designed using wideband antipodal tapered slot antennas, and two sets of PET-controlled phase shifters for E- and H-plane scanning are fabricated to steer...

Kim, Sang Gyu

2005-08-29T23:59:59.000Z

189

Numerical Studies of Collective Phenomena in Two-Dimensional Electron and Cold Atom Systems  

SciTech Connect (OSTI)

Numerical calculations were carried out to investigate a number of outstanding questions in both two-dimensional electron and cold atom systems. These projects aimed to increase our understanding of the properties of and prospects for non-Abelian states in quantum Hall matter.

Rezayi, Edward

2013-07-25T23:59:59.000Z

190

Two-Dimensional Numerical Modeling of Radio-Frequency Ion Engine Discharge  

E-Print Network [OSTI]

, Manuel Martinez-Sanchez August 2010 SSL # 14-10 #12;2 #12;3 Two-Dimensional Numerical Modeling of Radio-Frequency Ion Engine Discharge Michael Meng-Tsuan Tsay, Manuel Martinez-Sanchez August 2010 SSL # 14

191

Electrochemical Characterization of Liquid Phase Exfoliated Two-Dimensional Layers of Molybdenum Disulfide  

E-Print Network [OSTI]

Electrochemical Characterization of Liquid Phase Exfoliated Two- Dimensional Layers of Molybdenum of molybdenum disulfide (MoS2) obtained by liquid phase exfoliation of bulk MoS2 powder in 1-dodecyl-2-pyrrolidinone. The specific capacitances of the exfoliated flakes obtained using a 6 M KOH aqueous solution

192

Two dimensional thermoelectric platforms for thermocapillary droplet Man-Chi Liu,ac  

E-Print Network [OSTI]

the cooling function relies on the natural conduction and/or convection. A thermoelectric (TE) chipTwo dimensional thermoelectric platforms for thermocapillary droplet actuation Man-Chi Liu,ac Jin be driven to the cooler regions via surface tension modulation by varying the temperature. The usual method

Lin, Pei-Chun

193

Signatures of the Protein Folding Pathway in Two-Dimensional Ultraviolet Spectroscopy  

E-Print Network [OSTI]

Signatures of the Protein Folding Pathway in Two-Dimensional Ultraviolet Spectroscopy Jun Jiang of the signals provides a quantitative marker of protein folding status, accessible by both theoretical calculations and experiments. SECTION: Biophysical Chemistry and Biomolecules Protein folding is an important

Mukamel, Shaul

194

Quasi-equilibrium phase diagram and optical response in two-dimensional electron-hole system  

SciTech Connect (OSTI)

We study two dimensional electron-hole system in quasi-equilibrium. By using the self-consistent screened T matrix approximation, we present density dependence of ionization ratio. We also discuss the photoluminescence spectra, which are compared with experiment over the wide carrier density range.

Yoshioka, Takuya; Asano, Kenichi [Department of Physics, Osaka University, Toyonaka, Osaka, 560-0064 (Japan)

2013-12-04T23:59:59.000Z

195

Singular limits of a two-dimensional boundary value problem arising in corrosion modelling  

E-Print Network [OSTI]

Singular limits of a two-dimensional boundary value problem arising in corrosion modelling Juan D boundary . A very common boundary condition arising in corrosion modelling in a planar sample represented u on . We refer the reader to [11] and [4] for the derivation of this and related corrosion models

Ceragioli, Francesca

196

Vortex-vacancy interactions in two-dimensional easy-plane magnets G. M. Wysin  

E-Print Network [OSTI]

Vortex-vacancy interactions in two-dimensional easy-plane magnets G. M. Wysin Department of Physics of a magnetic vacancy site on a nearby magnetic vortex are analyzed on square, hexagonal and triangular lattices. When the vortex is centered on a vacancy, the critical anisotropies where the stable vortex structure

Wysin, Gary

197

Absence of Fragmentation in Two-Dimensional Bose-Einstein Condensation  

E-Print Network [OSTI]

); moreover, a mean-field analysis of a homogeneous three-dimensional Bose gas with repulsive interactions5Absence of Fragmentation in Two-Dimensional Bose-Einstein Condensation Juan Pablo Fern-dimensional finite trapped systems consist of fragmented condensates. We derive and diagonalize the one-body density

Mullin, William J.

198

Two-dimensional numerical methods in electromagnetic hypersonics including fully coupled Maxwell equations  

E-Print Network [OSTI]

the magnetic field source (solenoid or permanent magnet). To test the technique, we show the results obtainedTwo-dimensional numerical methods in electromagnetic hypersonics including fully coupled Maxwell Keplerlaan 1, 2200 AG Noordwijk, The Netherlands We describe a numerical technique for solving the coupled

D'Ambrosio, Domenic

199

COMSOL Modeling of Groundwater Flow and Contaminant Transport in Two-Dimensional Geometries With Heterogeneities  

E-Print Network [OSTI]

COMSOL Modeling of Groundwater Flow and Contaminant Transport in Two-Dimensional Geometries, Environmental Sys- tems. 1 Introduction Groundwater contributes an large portion of stream flow and subsequently% of a streams nitrogen load has been discharged from groundwater. The surficial aquifer geometry in this area

Gobbert, Matthias K.

200

Gravity Effects on Steady Two-Dimensional Partially Premixed MethaneAir Flames  

E-Print Network [OSTI]

cases due to buoyancy- induced entrainment, since advection of air into the outer reaction zone in an opposite direction to the gravity vector, causing air entrainment that enhances the fuel­air mixing andGravity Effects on Steady Two-Dimensional Partially Premixed Methane­Air Flames ZHUANG SHU, CHUN W

Aggarwal, Suresh K.

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Electrical spin injection in 2D semiconductors and topological insulators  

SciTech Connect (OSTI)

We have developed a theory of spin orientation by electric current in 2D semiconductors. It is shown that the spin depends on the relation between the energy and spin relaxation times and can vary by a factor of two for the limiting cases of fast and slow energy relaxation. For symmetrically-doped (110)-grown semiconductor quantum wells the effect of current-induced spin orientation is shown to exist due to random spatial variation of the Rashba spin-orbit splitting. We demonstrate that the spin depends strongly on the correlation length of this random spin-orbit field. We calculate the spin orientation degree in two-dimensional topological insulators. In high electric fields when the “streaming” regime is realized, the spin orientation degree weakly depends on the electric field and can reach values about 5%.

Golub, L. E.; Ivchenko, E. L. [Ioffe Physical-Technical Institute of the Russian Academy of Sciences, St. Petersburg (Russian Federation)

2013-12-04T23:59:59.000Z

202

Interaction-induced huge magnetoresistance in a high mobility two-dimensional electron gas  

SciTech Connect (OSTI)

A strong negative magnetoresistance is observed in a high-mobility two-dimensional electron gas in a GaAs/Al{sub 0.3}Ga{sub 0.7}As quantum well. We discuss that the negative magnetoresistance consists of a small peak induced by a combination of two types of disorder and a huge magnetoresistance explained by the interaction correction to the conductivity for mixed disorder.

Bockhorn, L.; Haug, R. J. [Institut für Festkörperphysik, Leibniz Universität Hannover, D-30167 Hannover (Germany); Gornyi, I. V. [Institut für Nanotechnologie, Karlsruher Institut of Technology, D-76021 Karlsruhe (Germany); Schuh, D. [Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93053 Regensburg (Germany); Wegscheider, W. [ETH Zürich (Switzerland)

2013-12-04T23:59:59.000Z

203

Confinement of magnetostatic forward volume waves in two-dimensional magnonic crystals with line defects  

SciTech Connect (OSTI)

The mode patterns of magnetostatic forward volume waves (MSFVWs) propagating in two-dimensional magnonic crystals with line defects via periodic variation in thickness of square lattice in a yttrium iron garnet thin film are reported. The theoretical approach based on Walker's equation was employed to analyze the confinement of MSFVWs in the line defects. A good agreement between the theoretical predictions and the experimental results was obtained.

Chi, K. H.; Zhu, Y. [Department of Electrical Engineering and Computer Science, and Institute for Surface and Interface Science, University of California, Irvine, California 92697 (United States); Tsai, C. S., E-mail: cstsai@uci.edu [Department of Electrical Engineering and Computer Science, and Institute for Surface and Interface Science, University of California, Irvine, California 92697 (United States); Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan (China)

2014-05-07T23:59:59.000Z

204

TWIST: a transient two-dimensional intra-subassembly thermal hydraulics model for LMFBRs  

SciTech Connect (OSTI)

Mathematical models and numerical methods for a two-dimensional porous body simulation of steady state and transient thermal-hydraulics conditions in LMFBR subassemblies resulting in the TWIST computer code are presented. Comparison of calculated results to steady state and transient out-of-pile sodium experiments show good agreement for cross-assembly temperature distributions for a wide range of heat transfer and flow conditions.

Khatib-Rahbar, M.; Cazzoli, E.G.

1984-06-03T23:59:59.000Z

205

Inverse fixed energy scattering problem for the two-dimensional nonlinear Schroedinger operator  

E-Print Network [OSTI]

This work studies the direct and inverse fixed energy scattering problem for two-dimensional Schroedinger equation with rather general nonlinear index of refraction. In particular, using the Born approximation we prove that all singularities of the unknown compactly supported potential from $L^2$-space can be obtained uniquely by the scattering data with fixed positive energy. The proof is based on the new estimates for the Faddeev-Green's function in $L^\\infty$-space.

Georgios Fotopoulos; Valery Serov

2014-12-01T23:59:59.000Z

206

Large scale two-dimensional arrays of magnesium diboride superconducting quantum interference devices  

SciTech Connect (OSTI)

Magnetic field sensors based on two-dimensional arrays of superconducting quantum interference devices were constructed from magnesium diboride thin films. Each array contained over 30?000 Josephson junctions fabricated by ion damage of 30?nm weak links through an implant mask defined by nano-lithography. Current-biased devices exhibited very large voltage modulation as a function of magnetic field, with amplitudes as high as 8?mV.

Cybart, Shane A., E-mail: scybart@ucsd.edu; Dynes, R. C. [Department of Physics, University of California San Diego, La Jolla, California 92093 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Wong, T. J.; Cho, E. Y. [Department of Physics, University of California San Diego, La Jolla, California 92093 (United States); Beeman, J. W. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Yung, C. S.; Moeckly, B. H. [Superconductor Technologies Inc., Santa Barbara, California 93111 (United States)

2014-05-05T23:59:59.000Z

207

Phase equilibria and interfacial properties of two-dimensional Yukawa fluids  

E-Print Network [OSTI]

Molecular dynamics simulations of two-dimensional soft Yukawa fluids are performed to analyze the effect that the range of interaction has on coexisting densities and line tension. The attractive one-component fluid and equimolar mixtures containing positive and negative particles are studied at different temperatures to locate the region where the vapor-solid and vapor-liquid phases are stable. When the range of interaction decreases, the critical temperature of the attractive one-component systems decreases. However, for the charged mixtures it increases, and this opposite behaviour is understood in terms of the repulsive interactions which are dominant for these systems. The stable phase diagram of two-dimensional fluids is defined for smaller values of the decay parameter \\lambda\\ than that of fluids in three dimensions. The two-dimensional attractive one-component fluid has stable liquid-vapor phase diagram for values of \\lambda<3, in contrast to the three-dimensional case, where stability has been observed even for values of \\lambda<15. The same trend is observed in equimolar mixtures of particles carrying opposite charges.

G. A. Méndez-Maldonado; M. González-Melchor; J. Alejandre

2012-07-13T23:59:59.000Z

208

Rashba spin splitting and cyclotron resonance in strained InGaAs/InP heterostructures with a two-dimensional electron gas  

SciTech Connect (OSTI)

Cyclotron resonance and magnetic transport in InP/InGaAs/InP heterostructures with axially symmetric quantum wells are studied experimentally at 4.2 K. An increase in the cyclotron mass at the Fermi level from 0.047m{sub 0} to 0.057m{sub 0} with an increase in the concentration of two-dimensional electrons from 5.5 Multiplication-Sign 10{sup 11} to 2.1 Multiplication-Sign 10{sup 12} cm{sup -3} is shown. The values of the Rashba spin splitting at the Fermi level are determined from Fourier analysis of the beats of Shubnikov-de Haas oscillations. The obtained experimental data are compared with the theoretical results of self-consistent calculations of the energy spectrum and cyclotron masses of 2D electrons performed using the eight-band k {center_dot} p Hamiltonian.

Kalinin, K. P., E-mail: kirill.kalinin@mail.ru; Krishtopenko, S. S.; Maremyanin, K. V.; Spirin, K. E.; Gavrilenko, V. I. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)] [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Biryukov, A. A.; Baidus, N. V.; Zvonkov, B. N. [Lobachevskyi State University, Physical-Technical Research Institute (Russian Federation)] [Lobachevskyi State University, Physical-Technical Research Institute (Russian Federation)

2013-11-15T23:59:59.000Z

209

X-ray ?-Laue diffraction analysis of Cu through-silicon vias: A two-dimensional and three-dimensional study  

SciTech Connect (OSTI)

Here, white X-ray ?-beam Laue diffraction is developed and applied to investigate elastic strain distributions in three-dimensional (3D) materials, more specifically, for the study of strain in Cu 10??m diameter–80??m deep through-silicon vias (TSVs). Two different approaches have been applied: (i) two-dimensional ?-Laue scanning and (ii) ?-beam Laue tomography. 2D ?-Laue scans provided the maps of the deviatoric strain tensor integrated along the via length over an array of TSVs in a 100??m thick sample prepared by Focused Ion Beam. The ?-beam Laue tomography analysis enabled to obtain the 3D grain and elemental distribution of both Cu and Si. The position, size (about 3??m), shape, and orientation of Cu grains were obtained. Radial profiles of the equivalent deviatoric strain around the TSVs have been derived through both approaches. The results from both methods are compared and discussed.

Sanchez, Dario Ferreira; Weleguela, Monica Larissa Djomeni; Audoit, Guillaume; Grenier, Adeline; Gergaud, Patrice; Bleuet, Pierre [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA/LETI, MINATEC Campus, F-38054 Grenoble (France); Laloum, David [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA/LETI, MINATEC Campus, F-38054 Grenoble (France); ST Microelectronics, 850 Rue Jean Monnet, F-38920 Crolles (France); Ulrich, Olivier; Micha, Jean-Sébastien; Robach, Odile [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA/INAC and CNRS, SPrAM, 17 rue des Martyrs, F-38054 Grenoble (France); Lorut, Frédéric [ST Microelectronics, 850 Rue Jean Monnet, F-38920 Crolles (France)

2014-10-28T23:59:59.000Z

210

2D Gauge Field Theory  

SciTech Connect (OSTI)

We show from the action integral that under the assumption of longitudinal dominance and transverse confinement, QCD4 in (3+1) dimensional space-time can be approximately compactified into QCD2 in (1+1) dimensional space-time. In such a process, we find the relation between the coupling constant $g(2D)$ in QCD2 and the coupling constant $g(4D)$ in QCD4. We also show that quarks and gluons in QCD2 acquire masses as a result of the compactification.

Koshelkin, Andrey V. [Moscow Institute for Physics and Engineering, Russia] [Moscow Institute for Physics and Engineering, Russia; Wong, Cheuk-Yin [ORNL] [ORNL

2012-01-01T23:59:59.000Z

211

Electron Transport in a Two-Dimensional Electron Gas at GaAs/AlGaAs Heterointerface  

E-Print Network [OSTI]

in condensed matters. Two-dimensional electron gas (2DEG) at the GaAs/AlGaAs hetero-interface o ersThesis Electron Transport in a Two-Dimensional Electron Gas at GaAs/AlGaAs Heterointerface under of the art samples, the mean free path of electrons exceeds 10;4 m at low temperature. The achievement

Katsumoto, Shingo

212

Absolute orientation-dependent TiN(001) step energies from two-dimensional equilibrium island shape and  

E-Print Network [OSTI]

Absolute orientation-dependent TiN(001) step energies from two-dimensional equilibrium island shape and coarsening measurements on epitaxial TiN(001) layers S. Kodambaka *, S.V. Khare, V. Petrova, A. Vailionis 1 microscopy was used to determine the equilibrium shapes of two-dimensional TiN vacancy islands on atomically

Khare, Sanjay V.

213

Orientation-dependent mobilities from analyses of two-dimensional TiN(111) island decay J. Bareo,1*  

E-Print Network [OSTI]

Orientation-dependent mobilities from analyses of two-dimensional TiN(111) island decay kinetics J (T = 1550-1700 K) low-energy electron microscopy measurements of two-dimensional TiN island coarsening/decay kinetics on TiN(111) terraces for which ( ) values are known [Phys. Rev. B 67 (2003) 35409

Khare, Sanjay V.

214

Well conditioned boundary integral equations for two-dimensional sound-hard scattering problems in domains with corners  

E-Print Network [OSTI]

Well conditioned boundary integral equations for two-dimensional sound-hard scattering problems-posed, well conditioned integral equation formulations for the solution of two-dimensional acoustic scattering-order, rapidly convergent numerical methods based on well-conditioned boundary integral equations for the case

Turc, Catalin

215

2-D linear motion system. Innovative technology summary report  

SciTech Connect (OSTI)

The US Department of Energy's (DOE's) nuclear facility decontamination and decommissioning (D and D) program requires buildings to be decontaminated, decommissioned, and surveyed for radiological contamination in an expeditious and cost-effective manner. Simultaneously, the health and safety of personnel involved in the D and D activities is of primary concern. D and D workers must perform duties high off the ground, requiring the use of manlifts or scaffolding, often, in radiologically or chemically contaminated areas or in areas with limited access. Survey and decontamination instruments that are used are sometimes heavy or awkward to use, particularly when the worker is operating from a manlift or scaffolding. Finding alternative methods of performing such work on manlifts or scaffolding is important. The 2-D Linear Motion System (2-D LMS), also known as the Wall Walker{trademark}, is designed to remotely position tools and instruments on walls for use in such activities as radiation surveys, decontamination, and painting. Traditional (baseline) methods for operating equipment for these tasks require workers to perform duties on elevated platforms, sometimes several meters above the ground surface and near potential sources of contamination. The Wall Walker 2-D LMS significantly improves health and safety conditions by facilitating remote operation of equipment. The Wall Walker 2-D LMS performed well in a demonstration of its precision, accuracy, maneuverability, payload capacity, and ease of use. Thus, this innovative technology is demonstrated to be a viable alternative to standard methods of performing work on large, high walls, especially those that have potential contamination concerns. The Wall Walker was used to perform a final release radiological survey on over 167 m{sup 2} of walls. In this application, surveying using a traditional (baseline) method that employs an aerial lift for manual access was 64% of the total cost of the improved technology. However, for areas over approximately 600 m{sup 2}, the Wall Walker would cost less than the baseline. Using the Wall Walker 2-D LMS, ALARA exposure and worker safety is improved, and there is potential for increased productivity. This innovative technology performed better than the baseline by providing real-time monitoring of the tool or instrument position. Also, the Wall Walker 2-D LMS can traverse any two-dimensional path at constant speeds of up to 18.3 linear meters per minute (60 linear feet per minute). The survey production rate for the innovative technology was about 0.6 m{sup 2}/min (6 ft{sup 2}/min); the baseline production rate was approximately 0.3 m{sup 2}/min (3 ft{sup 2}/min), using the same surveying instrument and maximum scanning rate.

NONE

1998-11-01T23:59:59.000Z

216

Diffusive transport of light in a two-dimensional disordered packing of disks: Analytical approach to transport-mean-free path  

E-Print Network [OSTI]

We study photon diffusion in a two-dimensional random packing of monodisperse disks as a simple model of granular media and wet foams. We assume that the intensity reflectance of disks is a constant. We present an analytic expression for the transport-mean-free path in terms of the velocity of light in the disks and host medium, radius and packing fraction of the disks, and the intensity reflectance. For the glass beads immersed in the air or water, we estimate transport-mean-free paths about half the experimental ones. For the air bubbles immersed in the water, transport-mean-free paths is an inverse function of liquid volume fraction of the model wet foam. This throws new light on the empirical law of Vera et. al, and promotes more realistic models.

Zeinab Sadjadi; MirFaez Miri; M. Reza Shaebani; Sareh Nakhaee

2008-09-20T23:59:59.000Z

217

Transparent Conducting Electrodes based on 1D and 2D Ag Nanogratings for Organic Photovoltaics  

E-Print Network [OSTI]

The optical and electrical properties of optically-thin one-dimensional (1D) Ag nanogratings and two-dimensional (2D) Ag nanogrids are studied, and their use as transparent electrodes in organic photovoltaics are explored. A large broadband and polarization-insensitive optical absorption enhancement in the organic light-harvesting layers is theoretically and numerically demonstrated using either single-layer 2D Ag nanogrids or two perpendicular 1D Ag nanogratings, and is attributed to the excitation of surface plasmon resonances and plasmonic cavity modes. Total photon absorption enhancements of 150% and 200% are achieved for the optimized single-layer 2D Ag nanogrids and double (top and bottom) perpendicular 1D Ag nanogratings, respectively.

Zeng, Beibei; Bartoli, Filbert J

2014-01-01T23:59:59.000Z

218

Plasmon mass and Drude weight in strongly spin-orbit-coupled two-dimensional electron gases  

E-Print Network [OSTI]

) spin- orbit-coupled 2D electron and hole gases, which are promising candidates for semiconductor spintronics,1 (ii) graphene2 (a monolayer of carbon atoms arranged in a 2D honeycomb lattice), which has attracted a great deal of interest because..., in the case of graphene) degree of freedom. This coupling, being of relativistic origin,12 naturally breaks Galilean invariance and is thus the basic reason for a quite sensitive dependence of several observables on electron-electron interactions, even...

Agarwal, Amit; Chesi, Stefano; Jungwirth, T.; Sinova, Jairo; Vignale, G.; Polini, Marco.

2011-01-01T23:59:59.000Z

219

One- and two-dimensional Stirling machine simulation using experimentally generated reversing flow turbuulence models  

SciTech Connect (OSTI)

The activities described in this report do not constitute a continuum but rather a series of linked smaller investigations in the general area of one- and two-dimensional Stirling machine simulation. The initial impetus for these investigations was the development and construction of the Mechanical Engineering Test Rig (METR) under a grant awarded by NASA to Dr. Terry Simon at the Department of Mechanical Engineering, University of Minnesota. The purpose of the METR is to provide experimental data on oscillating turbulent flows in Stirling machine working fluid flow path components (heater, cooler, regenerator, etc.) with particular emphasis on laminar/turbulent flow transitions. Hence, the initial goals for the grant awarded by NASA were, broadly, to provide computer simulation backup for the design of the METR and to analyze the results produced. This was envisaged in two phases: First, to apply an existing one-dimensional Stirling machine simulation code to the METR and second, to adapt a two-dimensional fluid mechanics code which had been developed for simulating high Rayleigh number buoyant cavity flows to the METR. The key aspect of this latter component was the development of an appropriate turbulence model suitable for generalized application to Stirling simulation. A final-step was then to apply the two-dimensional code to an existing Stirling machine for which adequate experimental data exist. The work described herein was carried out over a period of three years on a part-time basis. Forty percent of the first year`s funding was provided as a match to the NASA funds by the Underground Space Center, University of Minnesota, which also made its computing facilities available to the project at no charge.

Goldberg, L.F. [Univ. of Minnesota, Minneapolis, MN (United States)

1990-08-01T23:59:59.000Z

220

Recursion relations for the matrix elements of the two-dimensional harmonic oscillator  

E-Print Network [OSTI]

RECURSION RELATIONS FOR THE HAYRIX ELEi~iENTS OF THE T410- DiI&NSIONAL HAiB'lONIC OSCILLATOR A Thesis ABNER HERMAN FERESTEH Subraitted to the Graduate College of Texas A &: Yi University in. partial fulfillment of the requirement.... lid 0 ~~rt e t Hem. r~ ember August i/70 Becursion Belations for the Natrix Elements of the Two- Dimensional Harmon1c Oscillator. (August 1970) Avner Herman Ferester, B. B. A. , The City College of New York; Directed by: Professor J. B. Coon...

Ferester, Avner Herman

1970-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Parity-time electromagnetic diodes in a two-dimensional nonreciprocal photonic crystal  

SciTech Connect (OSTI)

We propose a kind of electromagnetic (EM) diode based on a two-dimensional nonreciprocal gyrotropic photonic crystal. This periodic microstructure has separately broken symmetries in both parity (P) and time-reversal (T) but obeys parity-time (PT) symmetry. This kind of diode could support bulk one-way propagating modes either for group velocity or phase velocity with various types of negative and positive refraction. This symmetry-broken system could be a platform to realize abnormal photoelectronic devices, and it may be analogous to an electron counterpart with one-way features.

He Cheng; Lu Minghui; Chen Yanfeng [National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China); Heng Xin [Bio-Rad Laboratories, Hercules, California 94547 (United States); Feng Liang [Department of Electrical Engineering, California Institute of Technology, Pasadena, California 91125 (United States)

2011-02-15T23:59:59.000Z

222

A two-dimensional numerical investigation of stratified wind flow over escarpments  

E-Print Network [OSTI]

, 195 6 Long, Robert R. , Models of Small-Scale Atmos heric Phenomena In- volvin Densit Stratification, John Hopkins University, Ba timore, 1956. 7 Long, Robert R. , A Laborator Model of Air Flow Over the Sierra Nevada Mountains, John Hopkins... to Topographical Effect on Vertical Wind Shear, " Journal of the Atmos heric Sciences, Vol. 27, 1970, pp. 884-889. 10 Kao, Timothy W. , Pao, Hsien-Ping, and Wei, Shuang N. , "Experimen- tal Study of Upstream Influence in the Two-dimensional Flow of a Stratified...

Fikes, Jay Stanley

1981-01-01T23:59:59.000Z

223

Nanolithographic Fabrication and Heterogeneous Reaction Studies ofTwo-Dimensional Platinum Model Catalyst Systems  

SciTech Connect (OSTI)

In order to better understand the fundamental components that govern catalytic activity, two-dimensional model platinum nanocatalyst arrays have been designed and fabricated. These catalysts arrays are meant to model the interplay of the metal and support important to industrial heterogeneous catalytic reactions. Photolithography and sub-lithographic techniques such as electron beam lithography, size reduction lithography and nanoimprint lithography have been employed to create these platinum nanoarrays. Both in-situ and ex-situ surface science techniques and catalytic reaction measurements were used to correlate the structural parameters of the system to catalytic activity.

Contreras, A.M.

2006-05-20T23:59:59.000Z

224

Two-dimensional modeling of apparent resistivity pseudosections in the Cerro Prieto region  

SciTech Connect (OSTI)

Using a finite-difference program (Dey, 1976) for two-dimensional modeling of apparent resistivity pseudosections obtained by different measuring arrays, four apparent resistivity pseudosections obtained at Cerro Prieto with a Schlumberger array by CFE personnel were modeled (Razo, 1978). Using geologic (Puente and de la Pena, 1978) and lithologic (Diaz, et al., 1981) data from the geothermal region, models were obtained which show clearly that, for the actual resistivity present in the zone, the information contained in the measured pseudosections is primarily due to the near-surface structure and does not show either the presence of the geothermal reservoir or the granitic basement which underlies it.

Vega, R.; Martinez, M.

1981-01-01T23:59:59.000Z

225

Phonon blocking by two dimensional electron gas in polar CdTe/PbTe heterojunctions  

SciTech Connect (OSTI)

Narrow-gap lead telluride crystal is an important thermoelectric and mid-infrared material in which phonon functionality is a critical issue to be explored. In this Letter, efficient phonon blockage by forming a polar CdTe/PbTe heterojunction is explicitly observed by Raman scattering. The unique phonon screening effect can be interpreted by recent discovery of high-density two dimensional electrons at the polar CdTe/PbTe(111) interface which paves a way for design and fabrication of thermoelectric devices.

Zhang, Bingpo; Cai, Chunfeng; Zhu, He; Wu, Feifei; Ye, Zhenyu; Chen, Yongyue; Li, Ruifeng; Kong, Weiguang; Wu, Huizhen, E-mail: hzwu@zju.edu.cn [Department of Physics and State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang 310027 (China)

2014-04-21T23:59:59.000Z

226

CURRENT - A Computer Code for Modeling Two-Dimensional, Chemically Reaccting, Low Mach Number Flows  

SciTech Connect (OSTI)

This report documents CURRENT, a computer code for modeling two- dimensional, chemically reacting, low Mach number flows including the effects of surface chemistry. CURRENT is a finite volume code based on the SIMPLER algorithm. Additional convergence acceleration for low Peclet number flows is provided using improved boundary condition coupling and preconditioned gradient methods. Gas-phase and surface chemistry is modeled using the CHEMKIN software libraries. The CURRENT user-interface has been designed to be compatible with the Sandia-developed mesh generator and post processor ANTIPASTO and the post processor TECPLOT. This report describes the theory behind the code and also serves as a user`s manual.

Winters, W.S.; Evans, G.H.; Moen, C.D.

1996-10-01T23:59:59.000Z

227

Ultrashort light bullets described by the two-dimensional sine-Gordon equation  

SciTech Connect (OSTI)

By using a reductive perturbation technique applied to a two-level model, this study puts forward a generic two-dimensional sine-Gordon evolution equation governing the propagation of femtosecond spatiotemporal optical solitons in Kerr media beyond the slowly varying envelope approximation. Direct numerical simulations show that, in contrast to the long-wave approximation, no collapse occurs, and that robust (2+1)-dimensional ultrashort light bullets may form from adequately chosen few-cycle input spatiotemporal wave forms. In contrast to the case of quadratic nonlinearity, the light bullets oscillate in both space and time and are therefore not steady-state lumps.

Leblond, Herve [Laboratoire de Photonique d'Angers, EA 4464 Universite d'Angers, 2 Bd. Lavoisier, FR-49045 Angers Cedex 01 (France); Mihalache, Dumitru [Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), 407 Atomistilor, RO-077125 Magurele-Bucharest (Romania); Academy of Romanian Scientists, 54 Splaiul Independentei, RO-050094 Bucharest (Romania)

2010-06-15T23:59:59.000Z

228

A quantum weak energy inequality for the Dirac field in two-dimensional flat spacetime  

E-Print Network [OSTI]

Fewster and Mistry have given an explicit, non-optimal quantum weak energy inequality that constrains the smeared energy density of Dirac fields in Minkowski spacetime. Here, their argument is adapted to the case of flat, two-dimensional spacetime. The non-optimal bound thereby obtained has the same order of magnitude, in the limit of zero mass, as the optimal bound of Vollick. In contrast with Vollick's bound, the bound presented here holds for all (non-negative) values of the field mass.

S. P. Dawson

2005-12-14T23:59:59.000Z

229

Evaluation of wrist strength limitations in two-dimensional biochemical modeling  

E-Print Network [OSTI]

. 99 3. 49 12. 03 2. 36 13. 94 4. 33 Mw is measured wrist radial deviation strength moment Std. Dev. is standard deviation 15. 5 15 z u 14. 5 rn 14 ~R 13, 5 13 g 12. 5 12 ~ 11. 5 Wrist Radial Deviation Strength 9O Bbow Angle (deg. ) 135... for the degree of MASTER OF SCIENCE May 1994 Major Subject: Industrial Engineering EVALUATION OF WRIST STRENGTH LIMITATIONS IN TWO-DIMENSIONAL BIOMECHANICAL MODELING A Thesis by KHALED WALID AL-EISAWI Submitted to Texas A&M University in partial...

Al-Eisawi, Khaled Walid

1994-01-01T23:59:59.000Z

230

Variable enstrophy flux and energy spectrum in two-dimensional turbulence with Ekman friction  

E-Print Network [OSTI]

Experiments and numerical simulations reveal that in the forward cascade regime, the energy spectrum of two-dimensional turbulence with Ekman friction deviates from Kraichnan's prediction of $k^{-3}$ power spectrum. In this letter we explain this observation using an analytic model based on variable enstrophy flux arising due to Ekman friction. We derive an expression for the enstrophy flux which exhibits a logarithmic dependence in the inertial range for the Ekman-friction dominated flows. The energy spectrum obtained using this enstrophy flux shows a power law scaling for large Reynolds number and small Ekman friction, but has an exponential behaviour for large Ekman friction and relatively small Reynolds number.

Mahendra K. Verma

2012-03-23T23:59:59.000Z

231

Heat transfer coefficients in two-dimensional Yukawa systems (numerical simulations)  

SciTech Connect (OSTI)

New data on heat transfer in two-dimensional Yukawa systems have been obtained. The results of a numerical study of the thermal conductivity for equilibrium systems with parameters close to the conditions of laboratory experiments in dusty plasma are presented. The Green-Kubo relations are used to calculate the heat transfer coefficients. The influence of dissipation (internal friction) on the heat transfer processes in nonideal systems is studied. New approximations are proposed for the thermal conductivity and diffusivity for nonideal dissipative systems. The results obtained are compared with the existing experimental and numerical data.

Khrustalyov, Yu. V., E-mail: yuri.khrustalyov@gmail.com; Vaulina, O. S. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

2013-05-15T23:59:59.000Z

232

Stochastic ratcheting of two dimensional colloids : Directed current and dynamical transitions  

E-Print Network [OSTI]

We present results of molecular dynamics simulations for two-dimensional repulsively interacting colloids driven by an one dimensional asymmetric and commensurate ratchet potential, switching on and off stochastically. The resultant time- and space-averaged directed current exhibits resonance with change in ratcheting frequency. The resonance frequency itself varies non-monotonically with density. We use scaling arguments to derive analytic expression for the directed current which reproduces these features. Our simulations reveal re-entrant dynamical transitions between solid and modulated liquid phases as a function of ratcheting frequency, associated with the variation of directed current.

Dipanjan Chakraborty; Debasish Chaudhuri

2014-07-09T23:59:59.000Z

233

The Energy Eigenvalues of the Two Dimensional Hydrogen Atom in a Magnetic Field  

E-Print Network [OSTI]

In this paper, the energy eigenvalues of the two dimensional hydrogen atom are presented for the arbitrary Larmor frequencies by using the asymptotic iteration method. We first show the energy eigenvalues for the no magnetic field case analytically, and then we obtain the energy eigenvalues for the strong and weak magnetic field cases within an iterative approach for $n=2-10$ and $m=0-1$ states for several different arbitrary Larmor frequencies. The effect of the magnetic field on the energy eigenvalues is determined precisely. The results are in excellent agreement with the findings of the other methods and our method works for the cases where the others fail.

A. Soylu; O. Bayrak; I. Boztosun

2007-03-13T23:59:59.000Z

234

An implicit logarithmic finite-difference technique for two dimensional coupled viscous Burgers’ equation  

SciTech Connect (OSTI)

This article describes a new implicit finite-difference method: an implicit logarithmic finite-difference method (I-LFDM), for the numerical solution of two dimensional time-dependent coupled viscous Burgers’ equation on the uniform grid points. As the Burgers’ equation is nonlinear, the proposed technique leads to a system of nonlinear systems, which is solved by Newton's iterative method at each time step. Computed solutions are compared with the analytical solutions and those already available in the literature and it is clearly shown that the results obtained using the method is precise and reliable for solving Burgers’ equation.

Srivastava, Vineet K., E-mail: vineetsriiitm@gmail.com [ISRO Telemetry, Tracking and Command Network (ISTRAC), Bangalore-560058 (India); Awasthi, Mukesh K. [Department of Mathematics, University of Petroleum and Energy Studies, Dehradun-248007 (India)] [Department of Mathematics, University of Petroleum and Energy Studies, Dehradun-248007 (India); Singh, Sarita [Department of Mathematics, WIT- Uttarakhand Technical University, Dehradun-248007 (India)] [Department of Mathematics, WIT- Uttarakhand Technical University, Dehradun-248007 (India)

2013-12-15T23:59:59.000Z

235

Quantum State Transfer in a Two-dimensional Regular Spin Lattice of Triangular Shape  

E-Print Network [OSTI]

Quantum state transfer in a triangular domain of a two-dimensional, equally-spaced, spin lat- tice with non-homogeneous nearest-neighbor couplings is analyzed. An exact solution of the one- excitation dynamics is provided in terms of 2-variable Krawtchouk orthogonal polynomials that have been recently defined. The probability amplitude for an excitation to transit from one site to another is given. For some values of the parameters, perfect transfer is shown to take place from the apex of the lattice to the boundary hypotenuse.

Hiroshi Miki; Satoshi Tsujimoto; Luc Vinet; Alexei Zhedanov

2012-03-12T23:59:59.000Z

236

Unitary transformations of a family of two-dimensional anharmonic oscillators  

E-Print Network [OSTI]

In this paper we analyze a recent application of perturbation theory by the moment method to a family of two-dimensional anharmonic oscillators. By means of straightforward unitary transformations we show that two of the models studied by the authors are separable. Other is unbounded from below and therefore cannot be successfully treated by perturbation theory unless a complex harmonic frequency is introduced in the renormalization process. We calculate the lowest resonance by means of complex-coordinate rotation and compare its real part with the eigenvalue estimated by the authors. A pair of the remaining oscillators are equivalent as they can be transformed into one another by unitary transformations.

Francisco M. Fernández; Javier Garcia

2014-09-24T23:59:59.000Z

237

Spectral effects simulation with two-dimensional magnetohydrodynamic models of the solar photosphere  

E-Print Network [OSTI]

To study the structure of spatially unresolved features of the solar photosphere, we calculated the Stokes profiles of seven photospheric iron lines using two-dimensional nonstationary MHD models of solar granulation for various amounts of magnetic flux (0, 10, 20, 30 mT). We investigate variations in the absolute wavelength shifts and bisectors of the I profiles, as well as variations in the zero-crossing wavelength shifts, amplitude and area asymmetry of the V profiles as functions of magnetic field strength and time. The center-to-limb variations of the Stokes profiles are analyzed. The iron abundance is found to be 7.57, with the photosphere inhomogeneities taken into account. Although most of the spectral effects simulated within the scope of the two-dimensional MHD models are in satisfactory agreement with observational data, these models cannot always give a quantitative agreement. The absolute wavelength shifts of the Stokes profiles of Fe II lines calculated with the MHD models are substantially smal...

Atroshchenko, I N; 10.3103/50884591305030022

2012-01-01T23:59:59.000Z

238

Ground-state and dynamical properties of two-dimensional dipolar Fermi liquids  

SciTech Connect (OSTI)

We study the ground-state properties of a two-dimensional spin-polarized fluid of dipolar fermions within the Euler–Lagrange Fermi-hypernetted-chain approximation. Our method is based on the solution of a scattering Schrödinger equation for the “pair amplitude” ?(g(r)), where g(r) is the pair distribution function. A key ingredient in our theory is the effective pair potential, which includes a bosonic term from Jastrow–Feenberg correlations and a fermionic contribution from kinetic energy and exchange, which is tailored to reproduce the Hartree–Fock limit at weak coupling. Very good agreement with recent results based on quantum Monte Carlo simulations is achieved over a wide range of coupling constants up to the liquid-to-crystal quantum phase transition. Using the fluctuation–dissipation theorem and a static approximation for the effective inter-particle interactions, we calculate the dynamical density–density response function, and furthermore demonstrate that an undamped zero-sound mode exists for any value of the interaction strength, down to infinitesimally weak couplings. -- Highlights: •We have studied the ground state properties of a strongly correlated two-dimensional fluid of dipolar fermions. •We have calculated the effective inter-particle interaction and the dynamical density–density response function. •We have shown that an undamped zero sound mode exists at any value of the interaction strength.

Abedinpour, Saeed H., E-mail: abedinpour@iasbs.ac.ir [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531 (Iran, Islamic Republic of); Asgari, Reza [School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531 (Iran, Islamic Republic of)] [School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531 (Iran, Islamic Republic of); Tanatar, B. [Department of Physics, Bilkent University, Bilkent, 06800 Ankara (Turkey)] [Department of Physics, Bilkent University, Bilkent, 06800 Ankara (Turkey); Polini, Marco [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56126 Pisa (Italy)] [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56126 Pisa (Italy)

2014-01-15T23:59:59.000Z

239

Local dissipation effects in two-dimensional quantum Josephson junction arrays with a magnetic field  

SciTech Connect (OSTI)

We study the quantum phase transitions in two-dimensional arrays of Josephson-couples junctions with short range Josephson couplings (given by the Josephson energy E{sub J}) and the charging energy E{sub C}. We map the problem onto the solvable quantum generalization of the spherical model that improves over the mean-field theory method. The arrays are placed on the top of a two-dimensional electron gas separated by an insulator. We include effects of the local dissipation in the presence of an external magnetic flux f={phi}/{phi}{sub 0} in square lattice for several rational fluxes f=0,(1/2),(1/3),(1/4), and (1/6). We also have examined the T=0 superconducting-insulator phase boundary as a function of a dissipation {alpha}{sub 0} for two different geometry of the lattice: square and triangular. We have found a critical value of the dissipation parameter independent on geometry of the lattice and presence magnetic field.

Polak, T.P.; Kopec, T.K. [Max-Planck-Institut fuer Physik komplexer Systeme, Noethnitzer Strasse 38, 01187 Dresden (Germany); Institute for Low Temperatures and Structure Research, Polish Academy of Sciences, POB 1410, 50-950 Wroclaw 2 (Poland)

2005-07-01T23:59:59.000Z

240

Experimental investigation of the thermal-hydraulics of gas jet expansion In a two-dimensional liquid pool  

E-Print Network [OSTI]

Gas jet blowdown in a two-dimensional liquid pool has been experimentally investigated. Two sets of experiments were performed: a set of hydrodynamic experiments, where a non-condensible gas is injected into a subcooled ...

Rothrock, Ray Alan

1978-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


241

Calculation of Solar P-mode Oscillation Frequency Splittings Based on a Two-dimensional Solar Model  

E-Print Network [OSTI]

We compute the p-mode oscillation frequencies and frequency splittings that arise in a two-dimensional model of the Sun that contains toroidal magnetic fields in its interior.

Linghuai Li; Sarbani Basu; Sabatino Sofia; Pierre Demarque

2008-10-27T23:59:59.000Z

242

Interference pattern of Bose-condensed gas in a 2D optical lattice  

E-Print Network [OSTI]

For the Bose-condensed gas confined in a magnetic trap and in a two-dimensional optical lattice, the non-uniform distribution of atoms in different lattice sites is considered based on Gross-Pitaevskii equation. A propagator method is used to investigate the time evolution of 2D interference patterns after (i)only the optical lattice is swithed off, and (ii)both the optical lattice and the magnetic trap are swithed off. An analytical description on the motion of side peaks in the interference patterns is presented by using the density distribution in a momentum space.

Shujuan Liu; Hongwei Xiong; Zhijun Xu; Guoxiang Huang

2003-04-25T23:59:59.000Z

243

Fusion rules and macroscopic loops from discretized approach to two-dimensional gravity  

E-Print Network [OSTI]

We investigate the multi-loop correlators and the multi-point functions for all of the scaling operators in unitary minimal conformal models coupled to two-dimensional gravity from the two-matrix model. We show that simple fusion rules for these scaling operators exist, and these are summarized in a compact form as fusion rules for loops. We clarify the role of the boundary operators and discuss its connection to how loops touch each other. We derive a general formula for the n-resolvent correlators, and point out the structure similar to the crossing symmetry of underlying conformal field theory. We discuss the connection of the boundary conditions of the loop correlators to the touching of loops for the case of the four-loop correlators.

Masahiro Anazawa

1997-04-04T23:59:59.000Z

244

Spatial bistability of two-dimensional Turing patterns in a reaction-diffusion system  

SciTech Connect (OSTI)

A Turing bifurcation from an uniform state to a striped patterned state was observed in experiments conducted in a single-phase spatial open gel reactor with the chlorite-iodide-malonic acid-starch (CIMA) reaction; previous experiments had revealed a bifurcation from a uniform state to hexagons rather than stripes. A modified reactor is used to demonstrate that the hexagonal and striped patterns are quasi-two-dimensional; this is further confirmed by a direct measurement of the third dimension of patterns with a camera of high resolution in depth of field. For some range of chemical concentrations the hexagonal and striped patterns are bistable; this is the first evidence of spatial bistability between Turing structures. 24 refs., 5 tabs.

Ouyang, Q.; Swinney, H.L. [Univ. of Texas, Austin, TX (United States); Noszticzius, Z. [Technical Univ. of Budapest (Hungary)

1992-08-06T23:59:59.000Z

245

Lifshitz transitions and crystallization of fully polarized dipolar fermions in an anisotropic two-dimensional lattice  

SciTech Connect (OSTI)

We consider a two-dimensional model of noninteracting chains of spinless fermions weakly coupled via a small interchain hopping and a repulsive interchain interaction. The phase diagram of this model has a surprising feature: an abrupt change in the Fermi surface as the interaction is increased. We study in detail this metanematic transition and show that the well-known 2(1/2)-order Lifshitz transition is the critical end point of this first-order quantum phase transition. Furthermore, in the vicinity of the end point, the order parameter has a nonperturbative BCS-type form. We also study a competing crystallization transition in this model and derive the full phase diagram. This physics can be demonstrated experimentally in dipolar ultracold atomic or molecular gases. In the presence of a harmonic trap, it manifests itself as a sharp jump in the density profile.

Carr, Sam T. [Institut fuer Theorie der Kondensierten Materie, Karlsruher Institut fuer Technologie, 76128 Karlsruhe (Germany); DFG Center for Functional Nanostructures, Karlsruher Institut fuer Technologie, 76128 Karlsruhe (Germany); Quintanilla, Jorge [School of Physical Sciences, University of Kent, Canterbury CT2 7NH (United Kingdom); ISIS Spallation Facility, STFC Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0QX (United Kingdom); Betouras, Joseph J. [Department of Physics, Loughborough University, Loughborough LE11 3TU (United Kingdom)

2010-07-15T23:59:59.000Z

246

Two-dimensional computational modeling of sodium boiling in simulated LMFBR fuel-pin bundles  

SciTech Connect (OSTI)

Extensive sodium boiling tests have been carried out in two simulated LMFBR fuel pin bundles in the Thermal-Hydraulic Out-of-Reactor Safety (THORS) Facility at Oak Ridge National Laboratory. Experimental results from a 19-pin bundle (THORS Bundle 6A) have been previously reported, and experimental results from a 61-pin bundle (THORS Bundle 9) will be reported soon. The results discussed here are from the 19-pin bundle. Preliminary analysis has shown that the computational methods used and conclusions reached are equally valid for the 61-pin bundle, as well as the 19-pin in-reactor Sodium Loop Safety Facility (SLSF) W-1 experiment. The main result of THORS sodium boiling experimentation is that boiling behavior is determined by two-dimensional effects, i.e., the rates of mass, momentum and energy transfer in the direction perpendicular to the axes of the fuel pins.

Dearing, J.F.

1981-01-01T23:59:59.000Z

247

Two-dimensional space-resolved emission spectroscopy of laser ablation plasma in water  

SciTech Connect (OSTI)

We developed a method for two-dimensional space-resolved emission spectroscopy of laser-induced plasma in water to investigate the spatial distribution of atomic species involved in the plasma. Using this method, the laser ablation plasma produced on a Cu target in 5 mM NaCl aqueous solution was examined. The emission spectrum varied considerably depending on the detecting position. The temperature and the atomic density ratio N{sub Na}/N{sub Cu} at various detecting positions were evaluated by fitting emission spectra to a theoretical model based on the Boltzmann distribution. We are successful in observing even a small difference between the distributions of the plasma parameters along the directions vertical and horizontal to the surface. The present approach gives direct information for sound understanding of the behavior of laser ablation plasma produced on a solid surface in water.

Matsumoto, Ayumu; Tamura, Ayaka; Fukami, Kazuhiro; Ogata, Yukio H. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan); Sakka, Tetsuo [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510 (Japan)

2013-02-07T23:59:59.000Z

248

Two-dimensional cylindrical ion-acoustic solitary and rogue waves in ultrarelativistic plasmas  

SciTech Connect (OSTI)

The propagation of ion-acoustic (IA) solitary and rogue waves is investigated in a two-dimensional ultrarelativistic degenerate warm dense plasma. By using the reductive perturbation technique, the cylindrical Kadomtsev–Petviashvili (KP) equation is derived, which can be further transformed into a Korteweg–de Vries (KdV) equation. The latter admits a solitary wave solution. However, when the frequency of the carrier wave is much smaller than the ion plasma frequency, the KdV equation can be transferred to a nonlinear Schrödinger equation to study the nonlinear evolution of modulationally unstable modified IA wavepackets. The propagation characteristics of the IA solitary and rogue waves are strongly influenced by the variation of different plasma parameters in an ultrarelativistic degenerate dense plasma. The present results might be helpful to understand the nonlinear electrostatic excitations in astrophysical degenerate dense plasmas.

Ata-ur-Rahman [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan) [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); National Centre for Physics at QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Ali, S. [National Centre for Physics at QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan)] [National Centre for Physics at QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Moslem, W. M. [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt)] [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt); Mushtaq, A. [National Centre for Physics at QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan) [National Centre for Physics at QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Department of Physics, Abdul Wali Khan University, Mardan 23200 (Pakistan)

2013-07-15T23:59:59.000Z

249

Descriptions of membrane mechanics from microscopic and effective two-dimensional perspectives  

E-Print Network [OSTI]

Mechanics of fluid membranes may be described in terms of the concepts of mechanical deformations and stresses, or in terms of mechanical free-energy functions. In this paper, each of the two descriptions is developed by viewing a membrane from two perspectives: a microscopic perspective, in which the membrane appears as a thin layer of finite thickness and with highly inhomogeneous material and force distributions in its transverse direction, and an effective, two-dimensional perspective, in which the membrane is treated as an infinitely thin surface, with effective material and mechanical properties. A connection between these two perspectives is then established. Moreover, the functional dependence of the variation in the mechanical free energy of the membrane on its mechanical deformations is first studied in the microscopic perspective. The result is then used to examine to what extent different, effective mechanical stresses and forces can be derived from a given, effective functional of the mechanical free energy.

Michael A. Lomholt; Ling Miao

2006-07-25T23:59:59.000Z

250

Violent relaxation in two-dimensional flows with varying interaction range  

E-Print Network [OSTI]

Understanding the relaxation of a system towards equilibrium is a longstanding problem in statistical mechanics. Here we address the role of long-range interactions in this process by considering a class of two-dimensional or geophysical flows where the interaction between fluid particles varies with the distance as $\\sim$$r^{$\\alpha$--2}$ with $\\alpha$ \\textgreater{} 0. Previous studies in the Euler case $\\alpha$ = 2 had shown convergence towards a variety of quasi-stationary states by changing the initial state. Unexpectedly, all those regimes are recovered by changing $\\alpha$ with a prescribed initial state. For small $\\alpha$, a coarsening process leads to the formation of a sharp interface between two regions of homogenized $\\alpha$-vorticity; for large $\\alpha$, the flow is attracted to a stable dipolar structure through a filamentation process.

Venaille, A; Ruffo, S

2015-01-01T23:59:59.000Z

251

SAS4A simulation of the OPERA-15 two-dimensional voiding experiment. [LMFBR  

SciTech Connect (OSTI)

A major effort is currently being pursued to validate the SAS4A LMFBR accident analysis code. Part of this effort involves SAS4A analysis of both in-pile and out-of-pile safety experiments. Such an experiment is the fifteen-pin Out-of-Pile Explusion and Reentry Apparatus (OPERA) test run at Argonne National Laboratory. This test uses a fifteen-pin triangular-shaped bundle of simulant fuel pins to demonstrate two-dimensional voiding behavior in a LMFBR subassembly during a Loss-of-Flow (LOF) accident. This experiment was chosen for SAS4A analysis both for its value in code validation and its usefulness in evaluating the limitations of the one-dimensional SAS4A sodium voiding model in accident analysis.

Briggs, L.L.

1984-01-01T23:59:59.000Z

252

The friction factor of two-dimensional rough-boundary turbulent soap film flows  

E-Print Network [OSTI]

We use momentum transfer arguments to predict the friction factor $f$ in two-dimensional turbulent soap-film flows with rough boundaries (an analogue of three-dimensional pipe flow) as a function of Reynolds number Re and roughness $r$, considering separately the inverse energy cascade and the forward enstrophy cascade. At intermediate Re, we predict a Blasius-like friction factor scaling of $f\\propto\\textrm{Re}^{-1/2}$ in flows dominated by the enstrophy cascade, distinct from the energy cascade scaling of $\\textrm{Re}^{-1/4}$. For large Re, $f \\sim r$ in the enstrophy-dominated case. We use conformal map techniques to perform direct numerical simulations that are in satisfactory agreement with theory, and exhibit data collapse scaling of roughness-induced criticality, previously shown to arise in the 3D pipe data of Nikuradse.

Nicholas Guttenberg; Nigel Goldenfeld

2008-08-11T23:59:59.000Z

253

Two-dimensional nanostructured Y{sub 2}O{sub 3} particles for viscosity modification  

SciTech Connect (OSTI)

Nanoparticle additives have been shown to improve the mechanical and transport phenomena of various liquids; however, little has been done to try and explain the rheological modifications provided from such modifications from a theoretical standpoint. Here, we report a non-Einstein-like reduction of viscosity of mineral oil with the utilization of yttrium oxide nanosheet additives. Experimental results, coupled with generalized smoothed-particle hydrodynamics simulations, provide insight into the mechanism behind this reduction of fluid shear stress. The ordered inclination of these two-dimensional nanoparticle additives markedly improves the lubricating properties of the mineral oil, ultimately reducing the friction, and providing a way in designing and understanding next generation of lubricants.

He, Xingliang; Xiao, Huaping; Liang, Hong, E-mail: hliang@tamu.edu [Department of Mechanical Engineering, Texas A and M University, College Station, Texas 77843-3123 (United States); Kyle, Jonathan P.; Terrell, Elon J. [Department of Mechanical Engineering, Columbia University, New York, New York 10027 (United States)

2014-04-21T23:59:59.000Z

254

Epitaxial two-dimensional nitrogen atomic sheet in GaAs  

SciTech Connect (OSTI)

We have grown an epitaxial two-dimensional nitrogen (N) atomic sheet in GaAs by using the site-controlled N ?-doping technique. We observed a change of the electronic states in N ?-doped GaAs from the isolated impurity centers to the delocalized impurity band at 1.49?eV with increasing N-doping density. According to the excitation-power- and temperature-dependent photoluminescence (PL) spectra, the emission related to localized levels below the impurity band edge was dominant at low excitation power and temperature, whereas the effects of the localized levels can be neglected by increasing the excitation power and temperature. Furthermore, a clear Landau shift of the PL-peak energy was observed at several Tesla in the Faraday configuration, in contrast to the case in the impurity limit.

Harada, Yukihiro, E-mail: y.harada@eedept.kobe-u.ac.jp; Yamamoto, Masuki; Baba, Takeshi; Kita, Takashi [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

2014-01-27T23:59:59.000Z

255

Two dimensional, two fluid model for sodium boiling in LMFBR fuel assemblies  

SciTech Connect (OSTI)

A two dimensional numerical model for the simulation of sodium boiling transient was developed using the two fluid set of conservation equations. A semiimplicit numerical differencing scheme capable of handling the problems associated with the ill-posedness implied by the complex characteristic roots of the two fluid problems was used, which took advantage of the dumping effect of the exchange terms. Of particular interest in the development of the model was the identification of the numerical problems caused by the strong disparity between the axial and radial dimensions of fuel assemblies. A solution to this problem was found which uses the particular geometry of fuel assemblies to accelerate the convergence of the iterative technique used in the model. Three sodium boiling experiments were simulated with the model, with good agreement between the experimental results and the model predictions.

Granziera, M.R.; Kazimi, M.S.

1980-05-01T23:59:59.000Z

256

Potential Energy Landscape of the Two-Dimensional XY Model: Higher-Index Stationary Points  

E-Print Network [OSTI]

The application of numerical techniques to the study of energy landscapes of large systems relies on sufficient sampling of the stationary points. Since the number of stationary points is believed to grow exponentially with system size, we can only sample a small fraction. We investigate the interplay between this restricted sample size and the physical features of the potential energy landscape for the two-dimensional $XY$ model in the absence of disorder with up to $N=100$ spins. Using an eigenvector-following technique, we numerically compute stationary points with a given Hessian index $I$ for all possible values of $I$. We investigate the number of stationary points, their energy and index distributions, and other related quantities, with particular focus on the scaling with $N$. The results are used to test a number of conjectures and approximate analytic results for the general properties of energy landscapes.

Dhagash Mehta; Ciaran Hughes; Michael Kastner; David J Wales

2014-12-10T23:59:59.000Z

257

Two-dimensional water quality modeling of Town Creek embayment on Guntersville Reservoir  

SciTech Connect (OSTI)

TVA investigated water quality of Town Creek embayment using a branched two-dimensional model of Guntersville Reservoir. Simulation results were compared in terms of algal biomass, nutrient concentrations, and volume of embayment with depleted dissolved oxygen. Stratification and flushing play a significant role in the embayment water quality. Storms introduce large loadings of organics, nutrients, and suspended solids. Dissolved oxygen depletion is most severe after storms followed by low flow that fails to flush the embayment. Embayment water quality responses to potential animal waste and erosion controls were explored. Modeling indicated animal waste controls were much more cost-effective than erosion controls. Erosion controls will decrease embayment suspended solids and thereby increase algal biomass due to greater light penetration. 29 refs., 16 figs., 4 tabs.

Bender, M.D.; Shiao, Ming C.; Hauser, G.E. (Tennessee Valley Authority, Norris, TN (USA). Engineering Lab.); Butkus, S.R. (Tennessee Valley Authority, Norris, TN (USA). Water Quality Dept.)

1990-09-01T23:59:59.000Z

258

Laser induced reentrant freezing in two-dimensional attractive colloidal systems  

E-Print Network [OSTI]

The effects of an externally applied one-dimensional periodic potential on the freezing/melting behaviour of two-dimensional systems of colloidal particles with a short-range attractive interaction are studied using Monte Carlo simulations. In such systems, incommensuration results when the periodicity of the external potential does not match the length-scale at which the minimum of the attractive potential occurs. To study the effects of this incommensuration, we consider two different models for the system. Our simulations for both these models show the phenomenon of reentrant freezing as the strength of the periodic potential is varied. Our simulations also show that different exotic phases can form when the strength of the periodic potential is high, depending on the length-scale at which the minimum of the attractive pair-potential occurs.

Pinaki Chaudhuri; Chinmay Das; Chandan Dasgupta; H. R. Krishnamurthy; A. K. Sood

2005-09-11T23:59:59.000Z

259

Two-dimensional AXUV-based radiated power density diagnostics on NSTX-U  

SciTech Connect (OSTI)

A new set of radiated-power-density diagnostics for the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak have been designed to measure the two-dimensional poloidal structure of the total photon emissivity profile in order to perform power balance, impurity transport, and magnetohydrodynamic studies. Multiple AXUV-diode based pinhole cameras will be installed in the same toroidal angle at various poloidal locations. The local emissivity will be obtained from several types of tomographic reconstructions. The layout and response expected for the new radially viewing poloidal arrays will be shown for different impurity concentrations to characterize the diagnostic sensitivity. The radiated power profile inverted from the array data will also be used for estimates of power losses during transitions from various divertor configurations in NSTX-U. The effect of in-out and top/bottom asymmetries in the core radiation from high-Z impurities will be addressed.

Faust, I.; Parker, R. R. [MIT - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Delgado-Aparicio, L.; Bell, R. E.; Diallo, A.; Gerhardt, S. P.; LeBlanc, B.; Kozub, T. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Tritz, K. [The Johns Hopkins University, Baltimore, Maryland 21209 (United States); Stratton, B. C. [MIT - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States)

2014-11-15T23:59:59.000Z

260

Study of vaneless diffuser rotating stall based on two-dimensional inviscid flow analysis  

SciTech Connect (OSTI)

Rotating stalls in vaneless diffusers are studied from the viewpoint that they are basically two-dimensional inviscid flow instability under the boundary conditions of vanishing velocity disturbance at the diffuser inlet and of vanishing pressure disturbance at the diffuser outlet. The linear analysis in the present report shows that the critical flow angle and the propagation velocity are functions of only the diffuser radius ratio. It is shown that the present analysis can reproduce most of the general characteristics observed in experiments: critical flow angle, propagation velocity, velocity, and pressure disturbance fields. It is shown that the vanishing velocity disturbance at the diffuser inlet is caused by the nature of impellers as a resistance and an inertial resistance, which is generally strong enough to suppress the velocity disturbance at the diffuser inlet. This explains the general experimental observations that vaneless diffuser rotating stalls are not largely affected by the impeller.

Tsujimoto, Yoshinobu; Yoshida, Yoshiki [Osaka Univ., Toyonaka, Osaka (Japan); Mori, Yasumasa [Mitsubishi Motors Corp., Ohta, Tokyo (Japan)

1996-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Coherence and population dynamics of chlorophyll excitations in FCP complex: Two-dimensional spectroscopy study  

E-Print Network [OSTI]

The energy transfer processes and coherent phenomena in the fucoxanthin-chlorophyll protein complex, which is responsible for the light harvesting function in marine algae diatoms, were investigated at 77 K by using two-dimensional electronic spectroscopy. Experiments performed on the femtosecond and picosecond timescales led to separation of spectral dynamics, witnessing evolutions of coherence and population states of the system in the spectral region of ${\\rm Q}_{y}$ transitions of chlorophylls $a$ and $c$. Analysis of the coherence dynamics allowed us to identify chlorophyll (Chl) $a$ and fucoxanthin intramolecular vibrations dominating over the first few picoseconds. Closer inspection of the spectral region of the ${\\rm Q}_{y}$ transition of Chl $c$ revealed previously not identified mutually non-interacting chlorophyll $c$ states participating in femtosecond or picosecond energy transfer to the Chl $a$ molecules. Consideration of separated coherent and incoherent dynamics allowed us to hypothesize the v...

Butkus, Vytautas; Augulis, Ram?nas; Gall, Andrew; Büchel, Claudia; Robert, Bruno; Zigmantas, Donatas; Valkunas, Leonas; Abramavicius, Darius

2015-01-01T23:59:59.000Z

262

Magnetic field control of the intraband optical absorption in two-dimensional quantum rings  

SciTech Connect (OSTI)

Linear and nonlinear optical absorption coefficients of the two-dimensional semiconductor ring in the perpendicular magnetic field B are calculated within independent electron approximation. Characteristic feature of the energy spectrum are crossings of the levels with adjacent nonpositive magnetic quantum numbers as the intensity B changes. It is shown that the absorption coefficient of the associated optical transition is drastically decreased at the fields corresponding to the crossing. Proposed model of the Volcano disc allows to get simple mathematical analytical results, which provide clear physical interpretation. An interplay between positive linear and intensity-dependent negative cubic absorption coefficients is discussed; in particular, critical light intensity at which additional resonances appear in the total absorption dependence on the light frequency is calculated as a function of the magnetic field and levels' broadening.

Olendski, O., E-mail: oolendski@ksu.edu.sa [King Abdullah Institute for Nanotechnology, King Saud University, P.O. Box 2454, Riyadh 11451 (Saudi Arabia); Barakat, T., E-mail: tbarakat@ksu.edu.sa [Department of Physics, King Saud University, P.O. Box 2454, Riyadh 11451 (Saudi Arabia)

2014-02-28T23:59:59.000Z

263

Collision-dependent power law scalings in two dimensional gyrokinetic turbulence  

SciTech Connect (OSTI)

Nonlinear gyrokinetics provides a suitable framework to describe short-wavelength turbulence in magnetized laboratory and astrophysical plasmas. In the electrostatic limit, this system is known to exhibit a free energy cascade towards small scales in (perpendicular) real and/or velocity space. The dissipation of free energy is always due to collisions (no matter how weak the collisionality), but may be spread out across a wide range of scales. Here, we focus on freely decaying two dimensional electrostatic turbulence on sub-ion-gyroradius scales. An existing scaling theory for the turbulent cascade in the weakly collisional limit is generalized to the moderately collisional regime. In this context, non-universal power law scalings due to multiscale dissipation are predicted, and this prediction is confirmed by means of direct numerical simulations.

Cerri, S. S., E-mail: silvio.sergio.cerri@ipp.mpg.de; Bañón Navarro, A.; Told, D. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Jenko, F. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching (Germany); Max-Planck/Princeton Center for Plasma Physics (Germany)

2014-08-15T23:59:59.000Z

264

Microbunching Instability in a Chicane: Two-Dimensional Mean Field Treatment  

SciTech Connect (OSTI)

We study the microbunching instability in a bunch compressor by a parallel code with some improved numerical algorithms. The two-dimensional charge/current distribution is represented by a Fourier series, with coefficients determined through Monte Carlo sampling over an ensemble of tracked points. This gives a globally smooth distribution with low noise. The field equations are solved accurately in the lab frame using retarded potentials and a novel choice of integration variables that eliminates singularities. We apply the scheme with parameters for the first bunch compressor system of FERMI{at}Elettra, with emphasis on the amplification of a perturbation at a particular wavelength. Gain curves agree with those of the linearized Vlasov model at long wavelengths, but show some deviation at the smallest wavelengths treated.

Bassi, G.; Ellison, James A.; Heinemann, Klaus; Warnock, Robert; /Liverpool U. /Cockroft Inst. /New Mexico U. /SLAC /LBL, Berkeley

2009-01-27T23:59:59.000Z

265

A two-dimensional, semi-analytic expansion method for nodal calculations  

SciTech Connect (OSTI)

Most modern nodal methods used today are based upon the transverse integration procedure in which the multi-dimensional flux shape is integrated over the transverse directions in order to produce a set of coupled one-dimensional flux shapes. The one-dimensional flux shapes are then solved either analytically or by representing the flux shape by a finite polynomial expansion. While these methods have been verified for most light-water reactor applications, they have been found to have difficulty predicting the large thermal flux gradients near the interfaces of highly-enriched MOX fuel assemblies. A new method is presented here in which the neutron flux is represented by a non-seperable, two-dimensional, semi-analytic flux expansion. The main features of this method are (1) the leakage terms from the node are modeled explicitly and therefore, the transverse integration procedure is not used, (2) the corner point flux values for each node are directly edited from the solution method, and a corner-point interpolation is not needed in the flux reconstruction, (3) the thermal flux expansion contains hyperbolic terms representing analytic solutions to the thermal flux diffusion equation, and (4) the thermal flux expansion contains a thermal to fast flux ratio term which reduces the number of polynomial expansion functions needed to represent the thermal flux. This new nodal method has been incorporated into the computer code COLOR2G and has been used to solve a two-dimensional, two-group colorset problem containing uranium and highly-enriched MOX fuel assemblies. The results from this calculation are compared to the results found using a code based on the traditional transverse integration procedure.

Palmtag, S.P. [Univ. of Missouri, Rolla, MO (United States). Dept. of Nuclear Engineering

1995-08-01T23:59:59.000Z

266

Controlled Vapor Phase Growth of Single Crystalline, Two-Dimensional GaSe  

E-Print Network [OSTI]

, and have the potential to enable next-generation electronic and optoelectronic devices. However, controlled-generation electronic and optoelectronic devices such as photodetectors and field-effect transistors. T wo-generation electronic and optoelectronic devices. Although most research has focused on 2D transition metal

Geohegan, David B.

267

On the diagonal susceptibility of the two-dimensional Ising model  

SciTech Connect (OSTI)

We consider the diagonal susceptibility of the isotropic 2D Ising model for temperatures below the critical temperature. For a parameter k related to temperature and the interaction constant, we extend the diagonal susceptibility to complex k inside the unit disc, and prove the conjecture that the unit circle is a natural boundary.

Tracy, Craig A. [Department of Mathematics, University of California, Davis, California 95616 (United States)] [Department of Mathematics, University of California, Davis, California 95616 (United States); Widom, Harold [Department of Mathematics, University of California, Santa Cruz, California 95064 (United States)] [Department of Mathematics, University of California, Santa Cruz, California 95064 (United States)

2013-12-15T23:59:59.000Z

268

Two-dimensional plasmon in a metallic monolayer on a semiconductor surface: Exchange-correlation effects  

E-Print Network [OSTI]

Department of Materials Science and Technology, Faculty of Engineering, Iwate University, 4-3-5 Ueda, Morioka, Appelstrasse 2, D-30167, Hannover, Germany Received 9 July 2002; published 30 December 2002 Taking account on the clean Si(111)-(7 7) surface, though the reconstruction from an ideally truncated surface into a (7 7

Hasegawa, Shuji

269

Two-dimensional single-stream electron motion in a coaxial diode with magnetic insulation  

SciTech Connect (OSTI)

One of the most widespread models of electrons drifting around the cathode in magnetrons is the single-stream state, which is the Brillouin stream with purely azimuthal motion. We describe a single-stream state in which electrons not only move in the azimuthal direction, but also along the axial direction, which is useful for consideration, for example, of relativistic magnetrons, MILOs, and coaxial transmission lines. Relations are given for the conditions of magnetic insulation for 2D electron motion, for 1D azimuthal and axial motion, and for synchronism of these streams with the operating waves of M-type microwave sources. Relations are also provided for the threshold of generation in magnetrons with 2D electron motion.

Fuks, Mikhail I.; Schamiloglu, Edl [Department of Electrical and Computer Engineering, MSC01 1100, University of New Mexico, Albuquerque, New Mexico 87131-0001 (United States)] [Department of Electrical and Computer Engineering, MSC01 1100, University of New Mexico, Albuquerque, New Mexico 87131-0001 (United States)

2014-05-15T23:59:59.000Z

270

Exact Solutions of 2d Supersymmetric Gauge Theories  

E-Print Network [OSTI]

We study dynamics of two-dimensional non-abelian gauge theories with N=(0,2) supersymmetry that include N=(0,2) supersymmetric QCD and its generalizations. In particular, we present the phase diagram of N=(0,2) SQCD and determine its massive and low-energy spectrum. We find that the theory has no mass gap, a nearly constant distribution of massive states, and lots of massless states that in general flow to an interacting CFT. For a range of parameters where supersymmetry is not dynamically broken at low energies, we give a complete description of the low-energy physics in terms of 2d N=(0,2) SCFTs using anomaly matching and modular invariance. Our construction provides a vast landscape of new N=(0,2) SCFTs which, for small values of the central charge, could be used for building novel heterotic models with no moduli and, for large values of the central charge, could be dual to AdS_3 string vacua.

Abhijit Gadde; Sergei Gukov; Pavel Putrov

2014-04-21T23:59:59.000Z

271

2D electron temperature diagnostic using soft x-ray imaging technique  

SciTech Connect (OSTI)

We have developed a two-dimensional (2D) electron temperature (T{sub e}) diagnostic system for thermal structure studies in a low-aspect-ratio reversed field pinch (RFP). The system consists of a soft x-ray (SXR) camera with two pin holes for two-kinds of absorber foils, combined with a high-speed camera. Two SXR images with almost the same viewing area are formed through different absorber foils on a single micro-channel plate (MCP). A 2D T{sub e} image can then be obtained by calculating the intensity ratio for each element of the images. We have succeeded in distinguishing T{sub e} image in quasi-single helicity (QSH) from that in multi-helicity (MH) RFP states, where the former is characterized by concentrated magnetic fluctuation spectrum and the latter, by broad spectrum of edge magnetic fluctuations.

Nishimura, K., E-mail: nishim11@nuclear.es.kit.ac.jp; Sanpei, A., E-mail: sanpei@kit.ac.jp; Tanaka, H.; Ishii, G.; Kodera, R.; Ueba, R.; Himura, H.; Masamune, S. [Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585 (Japan)] [Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585 (Japan); Ohdachi, S.; Mizuguchi, N. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)] [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

2014-03-15T23:59:59.000Z

272

Retrieval of Aerosol Optical Depth in Vicinity of Broken Clouds from Reflectance Ratios: Sensitivity Study  

SciTech Connect (OSTI)

We conducted a sensitivity study to better understand the potential of a new method for retrieving aerosol optical depth (AOD) under partly cloudy conditions. This method exploits reflectance ratios in the visible spectral range and provides an effective way to avoid three-dimensional (3D) cloud effects. The sensitivity study is performed for different observational conditions and random errors in input data. The results of the sensitivity study suggest that this ratio method has the ability to detect clear pixels even in close proximity to clouds. Such detection does not require a statistical analysis of the two-dimensional (2D) horizontal distribution of reflected solar radiation, and thus it could be customized for operational retrievals. In comparison with previously suggested approaches, the ratio method has the capability to increase the "harvest" of clear pixels. Similar to the traditional Independent Pixel Approximation (IPA), the ratio method has a low computational cost for retrieving AOD. In contrast to the IPA method, the ratio method provides much more accurate estimations of the AOD values under broken cloud conditions: pixel-based and domain-averaged estimations of errors in AOD are about 25% and 10%, respectively. Finally, both the ratio-based cloud screening and the accuracy of domain-averaged ratio-based AOD values do not suffer greatly when 5% random errors are introduced in the reflectances.

Kassianov, Evgueni I.; Ovtchinnikov, Mikhail; Berg, Larry K.; McFarlane, Sally A.; Flynn, Connor J.

2009-09-01T23:59:59.000Z

273

2D dilaton gravity made compact  

E-Print Network [OSTI]

We show that the equations of motion of two-dimensional dilaton gravity conformally coupled to a scalar field can be reduced to a single non-linear second-order partial differential equation when the coordinates are chosen to coincide with the two scalar fields, the matter field $f$ and the dilaton $\\phi$, which are present in the theory. This result may help solve and understand two- and higher-dimensional classical and quantum gravity.

M. Navarro

1998-05-18T23:59:59.000Z

274

MHD wave propagation in the neighbourhood of a two-dimensional null point  

E-Print Network [OSTI]

The nature of fast magnetoacoustic and Alfv\\'en waves is investigated in a zero $\\beta$ plasma. This gives an indication of wave propagation in the low $\\beta$ solar corona. It is found that for a two-dimensional null point, the fast wave is attracted to that point and the front of the wave slows down as it approaches the null point, causing the current density to accumulate there and rise rapidly. Ohmic dissipation will extract the energy in the wave at this point. This illustrates that null points play an important role in the rapid dissipation of fast magnetoacoustic waves and suggests the location where wave heating will occur in the corona. The Alfv\\'en wave behaves in a different manner in that the wave energy is dissipated along the separatrices. For Alfv\\'en waves that are decoupled from fast waves, the value of the plasma $\\beta$ is unimportant. However, the phenomenon of dissipating the majority of the wave energy at a specific place is a feature of both wave types.

J. A. McLaughlin; A. W. Hood

2007-12-11T23:59:59.000Z

275

Thermoelectric properties of two-dimensional topological insulators doped with nonmagnetic impurities  

SciTech Connect (OSTI)

We present a theoretical study on the thermoelectric properties of two-dimensional topological insulators (2DTIs) doped with nonmagnetic impurities. We develop a tractable model to calculate the electronic band structure without additional input parameters and to evaluate the thermoelectric properties of 2DTIs based on CdTe/HgTe quantum wells. We find that with increasing the doping concentration of nonmagnetic impurity, the edge states dominate the thermoelectric transport and the bulk-state conduction is largely suppressed. For typical sample parameters, the thermoelectric figure of merit ZT (a quantity used to characterize the conversion efficiency of a thermoelectric device between the heat and electricity) can be much larger than 1, which is a great advance over conventional thermoelectric materials. Furthermore, we show that with decreasing the 2DTI ribbon width or the Hall-bar width, ZT can be considerably further improved. These results indicate that the CdTe/HgTe 2DTIs doped with nonmagnetic impurities can be potentially applied as high-efficiency thermoelectric materials and devices.

Li, L. L., E-mail: lllihfcas@foxmail.com [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Xu, W., E-mail: wenxu-issp@aliyun.com [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Department of Physics, Yunnan University, Kunming 650091 (China)

2014-07-07T23:59:59.000Z

276

A General Theorem Relating the Bulk Topological Number to Edge States in Two-dimensional Insulators  

SciTech Connect (OSTI)

We prove a general theorem on the relation between the bulk topological quantum number and the edge states in two dimensional insulators. It is shown that whenever there is a topological order in bulk, characterized by a non-vanishing Chern number, even if it is defined for a non-conserved quantity such as spin in the case of the spin Hall effect, one can always infer the existence of gapless edge states under certain twisted boundary conditions that allow tunneling between edges. This relation is robust against disorder and interactions, and it provides a unified topological classification of both the quantum (charge) Hall effect and the quantum spin Hall effect. In addition, it reconciles the apparent conflict between the stability of bulk topological order and the instability of gapless edge states in systems with open boundaries (as known happening in the spin Hall case). The consequences of time reversal invariance for bulk topological order and edge state dynamics are further studied in the present framework.

Qi, Xiao-Liang; /Tsinghua U., Beijing /Stanford U., Phys. Dept.; Wu, Yong-Shi; /Utah U.; Zhang, Shou-Cheng; /Stanford U., Phys. Dept. /Tsinghua U., Beijing

2010-01-15T23:59:59.000Z

277

Apparatus for reading two-dimensional electrophoretograms containing. beta. -ray-emitting labeled compounds  

DOE Patents [OSTI]

An apparatus and method for electronically reading planar two-dimensional ..beta..-ray emitter-labeled gel electrophoretograms. A single, flat rectangular multiwire proportional chamber is placed in close proximity to the gel and the assembly placed in an intense uniform magnetic field disposed in a perpendicular manner to the rectangular face of the proportional chamber. Beta rays emitted in the direction of the proportional chamber are caused to execute helical motions which substantially preserve knowledge the coordinates of their origin in the gel. Perpendicularly oriented, parallel wire, parallel plane cathodes electronically sense the location of the ..beta..-rays from ionization generated thereby in a detection gas coupled with an electron avalanche effect resulting from the action of a parallel wire anode located therebetween. A scintillator permits the present apparatus to be rendered insensitive when signals are generated from cosmic rays incident on the proportional chamber. Resolution for concentrations of radioactive compounds in the gel exceeds 700-..mu..m. The apparatus and method of the present invention represent a significant improvement over conventional autoradiographic techniques in dynamic range, linearity and sensitivity of data collection. A concentration and position map for gel electrophoretograms having significant concentrations of labeled compounds and/or highly radioactive labeling nuclides can generally be obtained in less than one hour.

Anderson, H.L.; Kinnison, W.W.; Lillberg, J.W.

1985-04-30T23:59:59.000Z

278

Computational Model of the Mark-IV Electrorefiner: Two-Dimensional Potential and Current Distributions  

SciTech Connect (OSTI)

A computational model of the Mark-IV electrorefiner is currently being developed as a joint project between Idaho National Laboratory, Korea Atomic Energy Research Institute, Seoul National University, and the University of Idaho. As part of this model, the two-dimensional potential and current distributions within the molten salt electrolyte are calculated for U3+ , Zr4+ , and Pu3+ along with the total distributions, using the partial differential equation solver of the commercial Matlab software. The electrical conductivity of the electrolyte solution is shown to depend primarily on the composition of the electrolyte and to average 205 mho/m with a standard deviation of 2.5 × 10-5% throughout the electrorefining process. These distributions show that the highest potential gradients (thus, the highest current) exist directly between the two anodes and cathode. The total, uranium, and plutonium potential gradients are shown to increase throughout the process, with a slight decrease in that of zirconium. The distributions also show small potential gradients and very little current flow in the region far from the operating electrodes.

Supathorn Phongikaroon; Steven Herrmann; Michael F. Simpson

2011-02-01T23:59:59.000Z

279

Two-dimensional flow of foam around an obstacle: force measurements  

E-Print Network [OSTI]

A Stokes experiment for foams is proposed. It consists in a two-dimensional flow of a foam, confined between a water subphase and a top plate, around a fixed circular obstacle. We present systematic measurements of the drag exerted by the flowing foam on the obstacle, \\emph{versus} various separately controlled parameters: flow rate, bubble volume, bulk viscosity, obstacle size, shape and boundary conditions. We separate the drag into two contributions, an elastic one (yield drag) at vanishing flow rate, and a fluid one (viscous coefficient) increasing with flow rate. We quantify the influence of each control parameter on the drag. The results exhibit in particular a power-law dependence of the drag as a function of the bulk viscosity and the flow rate with two different exponents. Moreover, we show that the drag decreases with bubble size, and increases proportionally to the obstacle size. We quantify the effect of shape through a dimensioned drag coefficient, and we show that the effect of boundary conditions is small.

Benjamin Dollet; Florence Elias; Catherine Quilliet; Christophe Raufaste; Miguel Aubouy; Francois Graner

2004-10-13T23:59:59.000Z

280

Two-dimensional flows of foam: drag exerted on circular obstacles and dissipation  

E-Print Network [OSTI]

A Stokes experiment for foams is proposed. It consists in a two-dimensional flow of a foam, confined between a water subphase and a top plate, around a fixed circular obstacle. We present systematic measurements of the drag exerted by the flowing foam on the obstacle, \\emph{versus} various separately controlled parameters: flow rate, bubble volume, solution viscosity, obstacle size and boundary conditions. We separate the drag into two contributions, an elastic one (yield drag) at vanishing flow rate, and a fluid one (viscous coefficient) increasing with flow rate. We quantify the influence of each control parameter on the drag. The results exhibit in particular a power-law dependence of the drag as a function of the solution viscosity and the flow rate with two different exponents. Moreover, we show that the drag decreases with bubble size, increases with obstacle size, and that the effect of boundary conditions is small. Measurements of the streamwise pressure gradient, associated to the dissipation along the flow of foam, are also presented: they show no dependence on the presence of an obstacle, and pressure gradient depends on flow rate, bubble volume and solution viscosity with three independent power laws.

Benjamin Dollet; Florence Elias; Catherine Quilliet; Arnaud Huillier; Miguel Aubouy; Francois Graner

2004-11-22T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Development of a new two-dimensional Cartesian geometry nodal multigroup discrete-ordinates method  

SciTech Connect (OSTI)

The purpose of this work is the development and testing of a new family of methods for calculating the spatial dependence of the neutron density in nuclear systems described in two-dimensional Cartesian geometry. The energy and angular dependence of the neutron density is approximated using the multigroup and discrete ordinates techniques, respectively. The resulting FORTRAN computer code is designed to handle an arbitrary number of spatial, energy, and angle subdivisions. Any degree of scattering anisotropy can be handled by the code for either external source or fission systems. The basic approach is to (1) approximate the spatial variation of the neutron source across each spatial subdivision as an expansion in terms of a user-supplied set of exponential basis functions; (2) solve analytically for the resulting neutron density inside each region; and (3) approximate this density in the basis function space in order to calculate the next iteration flux-dependent source terms. In the general case the calculation is iterative due to neutron sources which depend on the neutron density itself, such as scattering interactions.

Pevey, R.E.

1982-07-01T23:59:59.000Z

282

Ionothermal Synthesis and Magnetic Studies of Novel Two-Dimensional Metal-Formate Frameworks  

SciTech Connect (OSTI)

Five novel two-dimensional frameworks containing formate-bridged metal-centered octahedra are synthesized ionothermally from two ionic liquids previously unused as solvents in hybrid synthesis, 2-hydroxyethylammonium (HEA) formate, and 1-hydroxy-3-proplyammonium (HPA) formate. Templating effects of the cation from each ionic liquid drive the formation of different structures. [NH{sub 3}C{sub 2}H{sub 4}OH]{sub 2}[M(CHO{sub 2}){sub 4}] (1: M = Co, 2: M = Ni) exhibit the same stoichiometry and connectivity as their manganese analogue (3: M = Mn), but the manganese form exhibits a different topology from 1 and 2. [NH{sub 3}C{sub 3}H6OH][M(CHO{sub 2}){sub 3}(H{sub 2}O)] (4: M = Co, 5: M = Mn) were synthesized using the HPA formate ionic liquid with a metal-formate connectivity related to those of 1-3. Canted antiferromagnetic ordering occurs at low temperatures (1: T{sub N} = 7.0 K, 2: T{sub N} = 4.6 K, 3: T{sub N} = 8.0 K, 4: T{sub N} = 7.0 K, 5: T{sub N} = 9.2 K), similar to the magnetic properties previously reported for other metal-formate hybrid materials.

Calderone, P.; Feygenson, M.; Forster, P.M.; Borkowski, L.A.; Teat, S.J. Aronson, M.C.; Parise, J.B.

2011-03-21T23:59:59.000Z

283

Search by quantum walks on two-dimensional grid without amplitude amplification  

E-Print Network [OSTI]

We study search by quantum walk on a finite two dimensional grid. The algorithm of Ambainis, Kempe, Rivosh (quant-ph/0402107) takes O(\\sqrt{N log N}) steps and finds a marked location with probability O(1/log N) for grid of size \\sqrt{N} * \\sqrt{N}. This probability is small, thus amplitude amplification is needed to achieve \\Theta(1) success probability. The amplitude amplification adds an additional O(\\sqrt{log N}) factor to the number of steps, making it O(\\sqrt{N} log N). In this paper, we show that despite a small probability to find a marked location, the probability to be within an O(\\sqrt{N}) neighbourhood (at an O(\\sqrt[4]{N}) distance) of the marked location is \\Theta(1). This allows to skip amplitude amplification step and leads to an O(\\sqrt{log N}) speed-up. We describe the results of numerical experiments supporting this idea, and we prove this fact analytically.

Andris Ambainis; Arturs Backurs; Nikolajs Nahimovs; Raitis Ozols; Alexander Rivosh

2011-12-14T23:59:59.000Z

284

Method for laser-based two-dimensional navigation system in a structured environment  

DOE Patents [OSTI]

A low power, narrow laser beam, generated by a laser carried by a mobile vehicle, is rotated about a vertical reference axis as the vehicle navigates within a structured environment. At least three stationary retroreflector elements are located at known positions, preferably at the periphery of the structured environment, with one of the elements having a distinctive retroreflection. The projected rotating beam traverses each retroreflector in succession, and the corresponding retroreflections are received at the vehicle and focussed on a photoelectric cell to generate corresponding electrical signals. The signal caused by the distinctive retroreflection serves as an angle-measurement datum. An angle encoder coupled to the apparatus rotating the projected laser beam provides the angular separation from this datum of the lines connecting the mobile reference axis to successive retroreflectors. This real-time angular data is utilized with the known locations of the retroreflectors to trigonometrically compute using three point resection, the exact real-time location of the mobile reference axis (hence the navigating vehicle) vis-a-vis the structured environment, e.g., in terms of two-dimensional Cartesian coordinates associated with the environment.

Boultinghouse, Karlan D. (Sandia Park, NM); Schoeneman, J. Lee (Albuquerque, NM); Tise, Bertice L. (Albuquerque, NM)

1989-01-01T23:59:59.000Z

285

Systematic Density Expansion of the Lyapunov Exponents for a Two-dimensional Random Lorentz Gas  

E-Print Network [OSTI]

We study the Lyapunov exponents of a two-dimensional, random Lorentz gas at low density. The positive Lyapunov exponent may be obtained either by a direct analysis of the dynamics, or by the use of kinetic theory methods. To leading orders in the density of scatterers it is of the form $A_{0}\\tilde{n}\\ln\\tilde{n}+B_{0}\\tilde{n}$, where $A_{0}$ and $B_{0}$ are known constants and $\\tilde{n}$ is the number density of scatterers expressed in dimensionless units. In this paper, we find that through order $(\\tilde{n}^{2})$, the positive Lyapunov exponent is of the form $A_{0}\\tilde{n}\\ln\\tilde{n}+B_{0}\\tilde{n}+A_{1}\\tilde{n}^{2}\\ln\\tilde{n} +B_{1}\\tilde{n}^{2}$. Explicit numerical values of the new constants $A_{1}$ and $B_{1}$ are obtained by means of a systematic analysis. This takes into account, up to $O(\\tilde{n}^{2})$, the effects of {\\it all\\/} possible trajectories in two versions of the model; in one version overlapping scatterer configurations are allowed and in the other they are not.

H. V. Kruis; Debabrata Panja; Henk van Beijeren

2005-09-30T23:59:59.000Z

286

Deformation-Driven Diffusion and Plastic Flow in Two-Dimensional Amorphous Granular Pillars  

E-Print Network [OSTI]

We report a combined experimental and simulation study of deformation-induced diffusion in compacted two-dimensional amorphous granular pillars, in which thermal fluctuations play negligible role. The pillars, consisting of bidisperse cylindrical acetal plastic particles standing upright on a substrate, are deformed uniaxially and quasistatically by a rigid bar moving at a constant speed. The plastic flow and particle rearrangements in the pillars are characterized by computing the best-fit affine transformation strain and non-affine displacement associated with each particle between two stages of deformation. The non-affine displacement exhibits exponential crossover from ballistic to diffusive behavior with respect to the cumulative deviatoric strain, indicating that in athermal granular packings, the cumulative deviatoric strain plays the role of time in thermal systems and drives effective particle diffusion. We further study the size-dependent deformation of the granular pillars by simulation, and find that different-sized pillars follow self-similar shape evolution during deformation. In addition, the yield stress of the pillars increases linearly with pillar size. Formation of transient shear lines in the pillars during deformation becomes more evident as pillar size increases. The width of these elementary shear bands is about twice the diameter of a particle, and does not vary with pillar size.

Wenbin Li; Jennifer M. Rieser; Andrea J. Liu; Douglas J. Durian; Ju Li

2015-02-04T23:59:59.000Z

287

Observation of Spin Coulomb Drag in a Two-Dimensional Electron Gas  

SciTech Connect (OSTI)

An electron propagating through a solid carries spin angular momentum in addition to its mass and charge. Of late there has been considerable interest in developing electronic devices based on the transport of spin, which offer potential advantages in dissipation, size, and speed over charge-based devices. However, these advantages bring with them additional complexity. Because each electron carries a single, fixed value (-e) of charge, the electrical current carried by a gas of electrons is simply proportional to its total momentum. A fundamental consequence is that the charge current is not affected by interactions that conserve total momentum, notably collisions among the electrons themselves. In contrast, the electron's spin along a given spatial direction can take on two values, {+-} {h_bar}/2 (conventionally {up_arrow}, {down_arrow}), so that the spin current and momentum need not be proportional. Although the transport of spin polarization is not protected by momentum conservation, it has been widely assumed that, like the charge current, spin current is unaffected by electron-electron (e-e) interactions. Here we demonstrate experimentally not only that this assumption is invalid, but that over a broad range of temperature and electron density, the flow of spin polarization in a two-dimensional gas of electrons is controlled by the rate of e-e collisions.

Weber, C.P.

2011-08-19T23:59:59.000Z

288

Electrostatics on the sphere with applications to Monte Carlo simulations of two dimensional polar fluids  

E-Print Network [OSTI]

We present two methods for solving the electrostatics of point charges and multipoles on the surface of a sphere, \\textit{i.e.} in the space $\\mathcal{S}_{2}$, with applications to numerical simulations of two-dimensional polar fluids. In the first approach, point charges are associated with uniform neutralizing backgrounds to form neutral pseudo-charges, while, in the second, one instead considers bi-charges, \\textit{i.e.} dumbells of antipodal point charges of opposite signs. We establish the expressions of the electric potentials of pseudo- and bi-charges as isotropic solutions of the Laplace-Beltrami equation in $\\mathcal{S}_{2}$. A multipolar expansion of pseudo- and bi-charge potentials leads to the electric potentials of mono- and bi-multipoles respectively. These potentials constitute non-isotropic solutions of the Laplace-Beltrami equation the general solution of which in spherical coordinates is recast under a new appealing form. We then focus on the case of mono- and bi-dipoles and build the theory...

Caillol, Jean-Michel

2015-01-01T23:59:59.000Z

289

Detection of point sources on two-dimensional images based on peaks  

E-Print Network [OSTI]

This article considers the detection of point sources in two dimensional astronomical images. The detection scheme we propose is based on peak statistics. We discuss the example of the detection of far galaxies in Cosmic Microwave Background experiments throughout the paper, although the method we present is totally general and can be used in many other fields of data analysis. We assume sources with a Gaussian profile --that is a fair approximation of the profile of a point source convolved with the detector beam in microwave experiments-- on a background modeled by a homogeneous and isotropic Gaussian random field characterized by a scale-free power spectrum. Point sources are enhanced with respect to the background by means of linear filters. After filtering, we identify local maxima and apply our detection scheme, a Neyman-Pearson detector that defines our region of acceptance based on the a priori pdf of the sources and the ratio of number densities. We study the different performances of some linear fil...

Lopez-Caniego, M; Sanz, J L; Barreiro, R B

2005-01-01T23:59:59.000Z

290

Detection of point sources on two-dimensional images based on peaks  

E-Print Network [OSTI]

This article considers the detection of point sources in two dimensional astronomical images. The detection scheme we propose is based on peak statistics. We discuss the example of the detection of far galaxies in Cosmic Microwave Background experiments throughout the paper, although the method we present is totally general and can be used in many other fields of data analysis. We assume sources with a Gaussian profile --that is a fair approximation of the profile of a point source convolved with the detector beam in microwave experiments-- on a background modeled by a homogeneous and isotropic Gaussian random field characterized by a scale-free power spectrum. Point sources are enhanced with respect to the background by means of linear filters. After filtering, we identify local maxima and apply our detection scheme, a Neyman-Pearson detector that defines our region of acceptance based on the a priori pdf of the sources and the ratio of number densities. We study the different performances of some linear filters that have been used in this context in the literature: the Mexican Hat wavelet, the matched filter and the scale-adaptive filter. We consider as well an extension to two dimensions of the biparametric scale adaptive filter (BSAF). The BSAF depends on two parameters which are determined by maximizing the number density of real detections while fixing the number density of spurious detections. For our detection criterion the BSAF outperforms the other filters in the interesting case of white noise.

M. Lopez-Caniego; D. Herranz; J. L. Sanz; R. B. Barreiro

2005-03-07T23:59:59.000Z

291

Two dimensional Sen connections and quasi-local energy-momentum  

E-Print Network [OSTI]

The recently constructed two dimensional Sen connection is applied in the problem of quasi-local energy-momentum in general relativity. First it is shown that, because of one of the two 2 dimensional Sen--Witten identities, Penrose's quasi-local charge integral can be expressed as a Nester--Witten integral.Then, to find the appropriate spinor propagation laws to the Nester--Witten integral, all the possible first order linear differential operators that can be constructed only from the irreducible chiral parts of the Sen operator alone are determined and examined. It is only the holomorphy or anti-holomorphy operator that can define acceptable propagation laws. The 2 dimensional Sen connection thus naturally defines a quasi-local energy-momentum, which is precisely that of Dougan and Mason. Then provided the dominant energy condition holds and the 2-sphere S is convex we show that the next statements are equivalent: i. the quasi-local mass (energy-momentum) associated with S is zero; ii.the Cauchy development $D(\\Sigma)$ is a pp-wave geometry with pure radiation ($D(\\Sigma)$ is flat), where $\\Sigma$ is a spacelike hypersurface whose boundary is S; iii. there exist a Sen--constant spinor field (two spinor fields) on S. Thus the pp-wave Cauchy developments can be characterized by the geometry of a two rather than a three dimensional submanifold.

L. B. Szabados

1994-02-02T23:59:59.000Z

292

Spectral properties of a hybrid-qubit model based on a two-dimensional quantum dot  

E-Print Network [OSTI]

The design and study of hybrid qubits is driven by their ability to get along the best of charge qubits and of spin qubits, {\\em i.e.} the speed of operation of the former and the very slow decoherence rates of the latter ones. There are several proposals to implement hybrid qubits, this works focuses on the spectral properties of an one-electron hybrid qubit. By design, the information would be stored in the electronic spin and the switching between the qubit basis states would be achieved using an external ac electric field. The electron is confined in a two-dimensional quantum dot, whose confining potential is given by a quartic potential, features that are typical of GaAS quantum dots. Besides the confining potential that characterizes the quantum dot there are two static magnetic fields applied to the system, one is a large constant Zeeman field and the other one has a constant gradient. We study the spectral properties of the model Hamiltonian, a Scr\\"odinger-Pauli Hamiltonian with realistic parameters, using the Ritz method. In particular, we look for regions of the parameter space where the lowest eigenenergies and their eigenfunctions allow to define a qubit which is stable under perturbations to the design parameters. We put special attention to the constraints that the design imposes over the magnetic fields, the tuning of the energy gap between the qubit states and the expectation value of the spin operator where the information would be stored.

Alba Y. Ramos; Omar Osenda

2015-03-27T23:59:59.000Z

293

Design, testing and two-dimensional flow modeling of a multiple-disk fan  

SciTech Connect (OSTI)

A multiple-disk Tesla type fan has been designed, tested and analyzed two-dimensionally using the conservation of angular momentum principle. Experimental results showed that such multiple-disk fans exhibited exceptionally low performance characteristics, which could be attributed to the low viscosity, tangential nature of the flow, and large mechanical energy losses at both suction and discharge sections that are comparable to the total input power. By means of theoretical analysis, local and overall shearing stresses on the disk surfaces have been determined based on tangential and radial velocity distributions of the air flow of different volume flow rates at prescribed disk spaces and rotational speeds. Then the total power transmitted by rotating disks to air flow, and the power acquired by the air flow in the gap due to transfer of angular momentum have been obtained by numerically integrating shearing stresses over the disk surfaces. Using the measured shaft and hydraulic powers, these quantities were utilized to evaluate mechanical energy losses associated with the suction and discharge sections of the fan. (author)

Engin, Tahsin; Oezdemir, Mustafa; Cesmeci, Sevki [Department of Mechanical Engineering, The University of Sakarya, Esentepe Campus, 54187 Sakarya (Turkey)

2009-11-15T23:59:59.000Z

294

A two-dimensional regional basin model of Williston basin hydrocarbon systems  

SciTech Connect (OSTI)

Institut Francais du Petrole`s two-dimensional model, TEMISPACK, is used to discuss the functioning of petroleum systems in the Williston basin along a 330-km-long section, focusing on four regional source intervals: Ordovician Yeoman formation, Lower Devonian Winnipegosis Formation, Upper Devonian-Lower Mississippian Bakken Formation, and Mississippian Lodgepole formation. Thermal history calibration against present temperature and source rock maturity profiles suggests that the Williston basin can be divided into a region of constant heat flow of about 55 mW/m{sup 2} away from the Nesson anticline, and a region of higher heat flow and enhanced thermal maturity in the vicinity of the Nesson anticline. Original kinetic parameters used in the calibration were derived for each of the four source rocks from Rock-Eval yield curves. Bakken overpressures are entirely due to oil generation, not compaction disequilibrium. Very low Bakken vertical permeabilities range from 0.01 to 0.001 and are matched against observed overpressures, whereas Bakken porosities based on the model and confirmed by measurements are inferred to be also unusually low, around 3%.

Burrus, J.; Wolf, S.; Doligez, B. [Institut Francais due Petrole, Rueil-Malmaison (France)] [and others

1996-02-01T23:59:59.000Z

295

Chiral operators in two-dimensional (0,2) theories and a test of triality  

E-Print Network [OSTI]

In this paper we compute spaces of chiral operators in general two-dimensional (0,2) nonlinear sigma models, both in theories twistable to the A/2 or B/2 model, as well as in non-twistable theories, and apply them to check recent duality conjectures. The fact that in a nonlinear sigma model, the Fock vacuum can act as a section of a line bundle on the target space plays a crucial role in our (0,2) computations, so we begin with a review of this property. We also take this opportunity to show how even in (2,2) theories, the Fock vacuum encodes in this way choices of target space spin structures, and discuss how such choices enter the A and B model topological field theories. We then compute chiral operators in general (0,2) nonlinear sigma models, and apply them to test the recent Gadde-Gukov-Putrov triality proposal, which says that certain triples of (0,2) GLSMs should RG flow to nontrivial IR fixed points. We find that different UV theories in the same proposed universality class do not necessarily have the...

Guo, J; Sharpe, E

2015-01-01T23:59:59.000Z

296

Renormalization theory of a two dimensional Bose gas: quantum critical point and quasi-condensed state  

E-Print Network [OSTI]

We present a renormalization group construction of a weakly interacting Bose gas at zero temperature in the two-dimensional continuum, both in the quantum critical regime and in the presence of a condensate fraction. The construction is performed within a rigorous renormalization group scheme, borrowed from the methods of constructive field theory, which allows us to derive explicit bounds on all the orders of renormalized perturbation theory. Our scheme allows us to construct the theory of the quantum critical point completely, both in the ultraviolet and in the infrared regimes, thus extending previous heuristic approaches to this phase. For the condensate phase, we solve completely the ultraviolet problem and we investigate in detail the infrared region, up to length scales of the order $(\\lambda^3 \\rho_0)^{-1/2}$ (here $\\lambda$ is the interaction strength and $\\rho_0$ the condensate density), which is the largest length scale at which the problem is perturbative in nature. We exhibit violations to the formal Ward Identities, due to the momentum cutoff used to regularize the theory, which suggest that previous proposals about the existence of a non-perturbative non-trivial fixed point for the infrared flow should be reconsidered.

Serena Cenatiempo; Alessandro Giuliani

2014-07-18T23:59:59.000Z

297

Nonlinear transverse cascade and two-dimensional magnetohydrodynamic subcritical turbulence in plane shear flows  

E-Print Network [OSTI]

We find and investigate via numerical simulations self-sustained two-dimensional turbulence in a magnetohydrodynamic flow with a maximally simple configuration: plane, noninflectional (with a constant shear of velocity) and threaded by a parallel uniform background magnetic field. This flow is spectrally stable, so the turbulence is subcritical by nature and hence it can be energetically supported just by transient growth mechanism due to shear flow nonnormality. This mechanism appears to be essentially anisotropic in spectral (wavenumber) plane and operates mainly for spatial Fourier harmonics with streamwise wavenumbers less than a ratio of flow shear to the Alfv\\'{e}n speed, $k_y < S/u_A$ (i.e., the Alfv\\'{e}n frequency is lower than the shear rate). We focused on the analysis of the character of nonlinear processes and underlying self-sustaining scheme of the turbulence, i.e., on the interplay between linear transient growth and nonlinear processes, in spectral plane. Our study, being concerned with a ...

Mamatsashvili, G R; Chagelishvili, G D; Horton, W

2014-01-01T23:59:59.000Z

298

A two-dimensional (azimuthal-axial) particle-in-cell model of a Hall thruster  

SciTech Connect (OSTI)

We have developed a two-dimensional Particle-In-Cell model in the azimuthal and axial directions of the Hall thruster. A scaling method that consists to work at a lower plasma density to overcome constraints on time-step and grid-spacing is used. Calculations are able to reproduce the breathing mode due to a periodic depletion of neutral atoms without the introduction of a supplementary anomalous mechanism, as in fluid and hybrid models. Results show that during the increase of the discharge current, an electron-cyclotron drift instability (frequency in the range of MHz and wave number on the order of 3000 rad s{sup ?1}) is formed in the region of the negative gradient of magnetic field. During the current decrease, an axial electric wave propagates from the channel toward the exhaust (whose frequency is on the order of 400?kHz) leading to a broadening of the ion energy distribution function. A discussion about the influence of the scaling method on the calculation results is also proposed.

Coche, P.; Garrigues, L., E-mail: laurent.garrigues@laplace.univ-tlse.fr [LAPLACE (Laboratoire Plasma et Conversion d'Energie), Université de Toulouse, UPS, INPT Toulouse 118, route de Narbonne, F-31062 Toulouse cedex 9 (France); CNRS, LAPLACE, F-31062 Toulouse (France)

2014-02-15T23:59:59.000Z

299

Characterization of the Human Pancreatic Islet Proteome by Two-Dimensional LC/MS/MS  

SciTech Connect (OSTI)

Research to elucidate the pathogenesis of type 1 diabetes mellitus has traditionally focused on the genetic and immunological factors associated with the disease, and, until recently, has not considered the target cell. While there have been reports detailing proteomic analyses of established islet cell lines or isolated rodent islets, the information gained is not always easily extrapolated to humans. Therefore, extensive characterization of the human islet proteome could result in better understanding of islet biology and lead to more effective treatment strategies. We have applied a two-dimensional LC-MS/MS-based analysis to the characterization of the human islet proteome, resulting in the detection of 29,021 unique peptides corresponding to 4,925 proteins. As expected, major islet hormones (insulin, glucagon, somatostatin), beta-cell enriched secretory products (IAPP), ion channels (K-ATP channel), and transcription factors (PDX-1, Nkx 6.1, HNF-1 beta) were detected. In addition, significant proteome coverage of metabolic enzymes and cellular pathways was obtained, including the insulin signaling cascade and the MAP kinase, NF-??, and JAK/STAT pathways. This work represents the most extensive characterization of the human islet proteome to date and provides a peptide reference library that may be utilized in future studies of islet biology and type 1 diabetes.

Metz, Thomas O.; Jacobs, Jon M.; Gritsenko, Marina A.; Fontes, Ghislaine; Qian, Weijun; Camp, David G.; Poitout, Vincent J.; Smith, Richard D.

2006-12-01T23:59:59.000Z

300

Nucleation and Ordering of an Electrodeposited Two-Dimensional Crystal: Real-Time X-Ray Scattering and Electronic Measurements  

SciTech Connect (OSTI)

We have studied {ital in situ} the ordering of a two-dimensional Cu-Cl crystal electrodeposited on a Pt(111) surface. We simultaneously measured x-ray scattering and chronoamperometric transients during Cu desorption and subsequent ordering of the Cu-Cl crystal. In all cases, the current transient occurs on a shorter time scale than the development of crystalline order. The ordering time diverges with applied potential, consistent with the nucleation and growth of two-dimensional islands. We see a time-dependent narrowing of the x-ray peak, corresponding to the growing islands. {copyright} {ital 1998} {ital The American Physical Society}

Finnefrock, A.C.; Ringland, K.L.; Brock, J.D. [School of Applied Engineering Physics and Materials Science Center, Cornell University, Ithaca, New York 14853 (United States)] [School of Applied Engineering Physics and Materials Science Center, Cornell University, Ithaca, New York 14853 (United States); Buller, L.J.; Abruna, H.D. [Department of Chemistry and Materials Science Center, Cornell University, Ithaca, New York 14853 (United States)] [Department of Chemistry and Materials Science Center, Cornell University, Ithaca, New York 14853 (United States)

1998-10-01T23:59:59.000Z

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301

A Turbulent Constitutive Law for the Two-Dimensional Inverse Energy Cascade  

E-Print Network [OSTI]

We develop a fundamental approach to a turbulent constitutive law for the 2D inverse cascade, based upon a convergent multi-scale gradient (MSG) expansion. To first order in gradients we find that the turbulent stress generated by small-scale eddies is proportional not to strain but instead to `skew-strain,' i.e. the strain tensor rotated by $45^\\circ.$ The skew-strain from a given scale of motion makes no contribution to energy flux across eddies at that scale, so that the inverse cascade cannot be strongly scale-local. We show that this conclusion extends a result of Kraichnan for spectral transfer and is due to absence of vortex-stretching in 2D. This `weakly local' mechanism of inverse cascade requires a relative rotation between the principal directions of strain at different scales and we argue for this using both the dynamical equations of motion and also a heuristic model of `thinning' of small-scale vortices by an imposed large-scale strain. Carrying out our expansion to second-order in gradients, we find two additional terms in the stress that can contribute to energy cascade. The first is a Newtonian stress with an `eddy-viscosity' due to differential strain-rotation, and the second is a tensile stress exerted along vorticity contour-lines. The latter was anticipated by Kraichnan for a very special model situation of small-scale vortex wave-packets in a uniform strain field. We prove a proportionality in 2D between the mean rates of differential strain-rotation and of vorticity-gradient stretching, analogous to a similar relation of Betchov for 3D. According to this result the second-order stresses will also contribute to inverse cascade when, as is plausible, vorticity contour-lines lengthen on average by turbulent advection.

Gregory L. Eyink

2005-12-10T23:59:59.000Z

302

Tile-Based Fisher-Ratio Software for Improved Feature Selection Analysis of Comprehensive Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry Data  

SciTech Connect (OSTI)

Two-dimensional (2D) gas chromatography coupled with time-of-flight mass spectrometry (GC × GC – TOFMS) is a highly capable instrumental platform that produces complex and information-rich multi-dimensional chemical data. The complex data can be overwhelming, especially when many samples (of various sample classes) are analyzed with multiple injections for each sample. Thus, the data must be analyzed in such a way to extract the most meaningful information. The pixel-based and peak table-based algorithmic use of Fisher ratios has been used successfully in the past to reduce the multi-dimensional data down to those chemical compounds that are changing between classes relative to those that are not (i.e., chemical feature selection). We report on the initial development of a computationally fast novel tile-based Fisher-ratio software that addresses challenges due to 2D retention time misalignment without explicitly aligning the data, which is a problem for both pixel-based and peak table- based methods. Concurrently, the tile-based Fisher-ratio software maximizes the sensitivity contrast of true positives against a background of potential false positives and noise. To study this software, eight compounds, plus one internal standard, were spiked into diesel at various concentrations. The tile-based F-ratio software was able to discover all spiked analytes, within the complex diesel sample matrix with thousands of potential false positives, in each possible concentration comparison, even at the lowest absolute spiked analyte concentration ratio of 1.06.

Marney, Luke C.; Siegler, William C.; Parsons, Brendon A.; Hoggard, Jamin C.; Wright, Bob W.; Synovec, Robert E.

2013-10-15T23:59:59.000Z

303

Comprehensive off-line, two-dimensional liquid chromotography. Application to the separation of peptide digest  

SciTech Connect (OSTI)

The separation of the peptide digests of myoglobin and bovine serum albumin was performed with an off-line combination of two commercial, conventional HPLC columns. The first column was packed with a strong ion exchanger and eluted with a KCl gradient. The second column was packed with particles of C{sub 18}-bonded silica and eluted with an acetonitrile gradient. The conditional peak capacities of the 2D separations achieved exceed 7000 under the experimental conditions investigated. This performance is achieved at the cost of an analysis time of the order of 28 hours. Possible improvements to the separation method described here are discussed.

Marchetti, Nicola [University of Tennessee, Knoxville (UTK); Guiochon, Georges A [ORNL

2008-01-01T23:59:59.000Z

304

Quasi-optical theory of relativistic surface-wave oscillators with one-dimensional and two-dimensional periodic planar structures  

SciTech Connect (OSTI)

Within the framework of a quasi-optical approach, we develop 2D and 3D self-consistent theory of relativistic surface-wave oscillators. Presenting the radiation field as a sum of two counter-propagating wavebeams coupled on a shallow corrugated surface, we describe formation of an evanescent slow wave. Dispersion characteristics of the evanescent wave following from this method are in good compliance with those found from the direct cst simulations. Considering excitation of the slow wave by a sheet electron beam, we simulate linear and nonlinear stages of interaction, which allows us to determine oscillation threshold conditions, electron efficiency, and output coupling. The transition from the model of surface-wave oscillator operating in the ?-mode regime to the canonical model of relativistic backward wave oscillator is considered. We also described a modified scheme of planar relativistic surface-wave oscillators exploiting two-dimensional periodic gratings. Additional transverse propagating waves emerging on these gratings synchronize the emission from a wide sheet rectilinear electron beam allowing realization of a Cherenkov millimeter-wave oscillators with subgigawatt output power level.

Ginzburg, N. S.; Zaslavsky, V. Yu. [Nizhny Novgorod State University, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation) [Nizhny Novgorod State University, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation); Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Malkin, A. M.; Sergeev, A. S. [Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation)] [Institute of Applied Physics of Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation)

2013-11-15T23:59:59.000Z

305

Carbon monoxide in the solar atmosphere I. Numerical method and two-dimensional models  

E-Print Network [OSTI]

The radiation hydrodynamic code CO5BOLD has been supplemented with the time-dependent treatment of chemical reaction networks. Advection of particle densities due to the hydrodynamic flow field is also included. The radiative transfer is treated frequency-independently, i.e. grey, so far. The upgraded code has been applied to two-dimensional simulations of carbon monoxide (CO) in the non-magnetic solar photosphere and low chromosphere. For this purpose a reaction network has been constructed, taking into account the reactions which are most important for the formation and dissociation of CO under the physical conditions of the solar atmosphere. The network has been strongly reduced to 27 reactions, involving the chemical species H, H2, C, O, CO, CH, OH, and a representative metal. The resulting CO number density is highest in the cool regions of the reversed granulation pattern at mid-photospheric heights and decreases strongly above. There, the CO abundance stays close to a value of 8.3 on the usual logarithmic abundance scale with [H]=12 but is reduced in hot shock waves which are a ubiquitous phenomenon of the model atmosphere. For comparison, the corresponding equilibrium densities have been calculated, based on the reaction network but also under assumption of instantaneous chemical equilibrium by applying the Rybicki & Hummer (RH) code by Uitenbroek (2001). Owing to the short chemical timescales, the assumption holds for a large fraction of the atmosphere, in particular the photosphere. In contrast, the CO number density deviates strongly from the corresponding equilibrium value in the vicinity of chromospheric shock waves. Simulations with altered reaction network clearly show that the formation channel via hydroxide (OH) is the most important one under the conditions of the solar atmosphere.

S. Wedemeyer-Boehm; I. Kamp; J. Bruls; B. Freytag

2005-03-23T23:59:59.000Z

306

Two dimensional point of use fuel cell : a final LDRD project report.  

SciTech Connect (OSTI)

The Proliferation Assessment (program area - Things Thin) within the Defense Systems and Assessment Investment Area desires high energy density and long-lived power sources with moderate currents (mA) that can be used as building blocks in platforms for the continuous monitoring of chemical, biological, and radiological agents. Fuel cells can be an optimum choice for a power source because of the high energy densities that are possible with liquid fuels. Additionally, power generation and fuel storage can be decoupled in a fuel cell for independent control of energy and power density for customized, application-driven power solutions. Direct methanol fuel cells (DMFC) are explored as a possible concept to develop into ultrathin or two-dimensional power sources. New developments in nanotechnology, advanced fabrication techniques, and materials science are exploited to create a planar DMFC that could be co-located with electronics in a chip format. Carbon nanotubes and pyrolyzed polymers are used as building block electrodes - porous, mechanically compliant current collectors. Directed assembly methods including surface functionalization and layer-by-layer deposition with polyelectrolytes are used to pattern, build, and add functionality to these electrodes. These same techniques are used to incorporate nanoscale selective electrocatalyst into the carbon electrodes to provide a high density of active electron transfer sites for the methanol oxidation and oxygen reduction reactions. The resulting electrodes are characterized in terms of their physical properties, electrocatalytic function, and selectivity to better understand how processing impacts their performance attributes. The basic function of a membrane electrode assembly is demonstrated for several prototype devices.

Zavadil, Kevin Robert; Hickner, Michael A. (Pennsylvania State University, University Park, PA); Gross, Matthew L. (Pennsylvania State University, University Park, PA)

2011-03-01T23:59:59.000Z

307

Two-dimensional iterative region-of-interest (ROI) reconstruction from truncated projection data  

SciTech Connect (OSTI)

A small detector or limited gantry rotation angles may cause data truncation, in which case the entire object cannot be completely reconstructed. However, a small region of interest (ROI) may be recoverable in certain truncation situations. Two analytical methods have been proposed for exact ROI reconstruction. Here we evaluate the capability of ROI reconstruction using an maximum-likelihood expectation-maximization (ML-EM) method, which directly solves the inverse problem of the system equations. ROI reconstruction using the ML-EM method is compared with that using the two analytical methods. Comparisons are based on reconstructions of four specifically designed, computer-simulated truncation cases. In the simulation, each reconstructed ROI is coupled with its counterpart in the nontruncated case to evaluate the accuracy of the reconstructed ROI. We found that, (a) in two truncation situations the ROI can be reconstructed by both the analytical methods and the two-dimensional ML-EM method, but the ML-EM method may produce a larger ROI; (b) for a truncation case that neither analytical algorithm is applicable, the ML-EM method provides a quantitative ROI reconstruction; and (c) for the well-known 'interior' truncation problem, neither the analytical methods nor the ML-EM method can perform an exact ROI reconstruction, but the ML-EM method provides informative ROI images. We also propose an analysis using the truncated projection matrix and its Moore-Penrose inverse matrix which can help to determine the recoverable ROI using iterative methods for a given truncation situation.

Zhang, B.; Zeng, G. L. [Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah 84108 (United States)

2007-03-15T23:59:59.000Z

308

Path-integral solution for a two-dimensional model with axial-vector-current--pseudoscalar derivative interaction  

SciTech Connect (OSTI)

We study a two-dimensional quantum field model with axial-vector-current--pseudoscalar derivative interaction using path-integral methods. We construct an effective Lagrangian by performing a chiral change in the fermionic variables leading to an exact solution of the model.

Botelho, L.C.L.

1985-03-15T23:59:59.000Z

309

A three-dimensional porous metal-organic framework constructed from two-dimensional sheets via interdigitation exhibiting dynamic features.  

SciTech Connect (OSTI)

A three-dimensional porous metal-organic framework (PCN-18) was constructed through interdigitating two-dimensional grid sheets composed of 4,4{prime}-(anthracene-9,10-diyl)dibenzoate and copper paddlewheel secondary building units, and its dynamic features were evidenced by gas sorption isotherms.

Ma, S.; Sun, D.; Forster, P. M.; Yuan, D.; Zhuang, W.; Chen, Y. S.; Parise, J. B.; Zhou, H. C. (Chemical Sciences and Engineering Division); (Texas A& M Univ.); (Univ. of Chicago); (Stony Brook Univ.)

2009-04-23T23:59:59.000Z

310

Optimal discrimination of quantum states on a two-dimensional Hilbert space by local operations and classical communication  

E-Print Network [OSTI]

We study the discrimination of multipartite quantum states by local operations and classical communication. We derive that any optimal discrimination of quantum states spanning a two-dimensional Hilbert space in which each party's space is finite dimensional is possible by local operations and one-way classical communication, regardless of the optimality criterion used and how entangled the states are.

Kenji Nakahira; Tsuyoshi Sasaki Usuda

2015-01-26T23:59:59.000Z

311

Magneto-electric coupling in a two-dimensional ballistic Josephson junction with in-plane magnetic texture  

E-Print Network [OSTI]

Magneto-electric coupling in a two-dimensional ballistic Josephson junction with in-plane magnetic, Germany (Dated: August 20, 2014) We study a Josephson junction made with a spin-textured bridge, when both-dimensional ballistic Josephson junction close to the critical temperature of the heterostructure, when an anomalous

Boyer, Edmond

312

Using inhomogeneity to raise the superconducting critical temperature in a two-dimensional Y. L. Loh and E. W. Carlson  

E-Print Network [OSTI]

Using inhomogeneity to raise the superconducting critical temperature in a two-dimensional XY model, USA Received 5 February 2007; published 27 April 2007 Superconductors with low superfluid density properties such as superconductivity. That is, does inhomogeneity help or harm superconductivity

Carlson, Erica

313

A two-dimensional finite element thermomechanical approach to a global stress-strain analysis of steel continuous casting  

E-Print Network [OSTI]

of steel continuous casting Michel Bellet, Alban Heinrich Ecole des Mines de Paris, Centre de Mise en Forme.bellet@ensmp.fr Synopsis This paper addresses the two-dimensional finite element simulation of steel continuous casting state (temperature, deformation, stresses) of steel all along the continuous casting machine. Both plane

Boyer, Edmond

314

Standing Waves in a Two-Dimensional Reaction-Diffusion Model with the Short-Wave Instability  

E-Print Network [OSTI]

Standing Waves in a Two-Dimensional Reaction-Diffusion Model with the Short-Wave Instability Milos 25, 1998; In Final Form: October 19, 1998 Various patterns of standing waves are found beyond the onset of the short-wave instability in a model reaction- diffusion system. These include plain

Epstein, Irving R.

315

Self-assembly of two-dimensional nanoclusters observed with STM: From surface molecules to surface superstructure  

E-Print Network [OSTI]

Self-assembly of two-dimensional nanoclusters observed with STM: From surface molecules to surface on the Si 111 - 3 3-Ag surface at submonolayer Au coverage. Self-assembly of these Au nanoclusters leads nanoclus- ter are discussed in terms of a substrate-mediated interaction among the Au adatoms, and the self-assembling

Hasegawa, Shuji

316

PHYSICAL REVIEW E 84, 046201 (2011) Reconstruction of two-dimensional phase dynamics from experiments on coupled oscillators  

E-Print Network [OSTI]

phase modeling methods to quantify the dynamics of pairs of coupled electrochemical oscillators, based electrochemical oscillators. We discuss the basic theory, which we apply for our system of two oscillators with noise and connect the two-dimensional and one-dimensional models [6,8,9]. We calculate the natural

Potsdam, Universität

317

Efficiency enhancement in a light-emitting diode with a two-dimensional surface grating photonic crystal  

E-Print Network [OSTI]

Efficiency enhancement in a light-emitting diode with a two-dimensional surface grating photonic 21 November 2003 We demonstrate a light-emitting diode exhibiting 1.7­2.7-fold enhancement in light light emitting diode LED , the ef- ficiency is limited to several percents by a low light extrac- tion

Baba, Toshihiko

318

The Hamiltonian structure of a two-dimensional rigid circular cylinder interacting dynamically with N point vortices  

E-Print Network [OSTI]

The Hamiltonian structure of a two-dimensional rigid circular cylinder interacting dynamically bracket for the dynamics of N point vortices in an unbounded plane. We then use this Hamiltonian structure, New Mexico State University, Las Cruces, New Mexico 88003 Jerrold E. Marsdenb) Control and Dynamical

Shashikanth, Banavara N.

319

Quasi-one-and quasi-two-dimensional perfect Bose gas: the second critical density and generalised condensation  

E-Print Network [OSTI]

) In this letter we discuss a relevance of the 3D Perfect Bose gas (PBG) condensation in extremely elongated condensation (vdBLP-GC) [10] of the Perfect Bose-Gas (PBG) for densities larger than the first, iQuasi-one- and quasi-two-dimensional perfect Bose gas: the second critical density and generalised

Boyer, Edmond

320

Energy Spectrum of a Relativistic Two-dimensional Hydrogen-like Atom in a Constant Magnetic Field of arbitrary strength  

E-Print Network [OSTI]

We compute, via a variational mixed-base method, the energy spectrum of a two dimensional relativistic atom in the presence of a constant magnetic field of arbitrary strength. The results are compared to those obtained in the non-relativistic and spinless case. We find that the relativistic spectrum does not present $s$ states.

V. M. Villalba; R. Pino

2001-01-23T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Sensitivity analysis of two-dimensional steady-state aquifer ow equations. Implications for groundwater ow model calibration  

E-Print Network [OSTI]

sensitivity, model calibration, well network design, groundwater flow modelling 1. Introduction Sensitivity for groundwater ow model calibration and validation N. Mazzillia, , V. Guinota , H. Jourdea a for two-dimensional groundwater flow model calibration and monitoring network design. Since the first step

Paris-Sud XI, Université de

322

Yield drag in a two-dimensional foam flow around a circular obstacle: Effect of liquid fraction  

E-Print Network [OSTI]

Yield drag in a two-dimensional foam flow around a circular obstacle: Effect of liquid fraction of foams around a circular obstacle within a long channel. In experiments, we confine the foam between liquid and glass surfaces. In simulations, we use a deterministic software, the Surface Evolver

Cox, Simon

323

Plastic Deformation of 2D Crumpled Wires  

E-Print Network [OSTI]

When a single long piece of elastic wire is injected trough channels into a confining two-dimensional cavity, a complex structure of hierarchical loops is formed. In the limit of maximum packing density, these structures are described by several scaling laws. In this paper it is investigated this packing process but using plastic wires which give origin to completely irreversible structures of different morphology. In particular, it is studied experimentally the plastic deformation from circular to oblate configurations of crumpled wires, obtained by the application of an axial strain. Among other things, it is shown that in spite of plasticity, irreversibility, and very large deformations, scaling is still observed.

M A F Gomes; V P Brito; A S O Coelho; C C Donato

2008-11-17T23:59:59.000Z

324

Classical stability of black hole Cauchy horizons in two-dimensional asymptotically flat space-times  

E-Print Network [OSTI]

In this paper we analyse the stability of black hole Cauchy horizons arising in a class of 2d dilaton gravity models. It is shown that due to the characteristic asymptotic Rindler form of the metric of these models, time dependent gravitational perturbations generated in the external region do not necessarily blow-up when propagated along the Cauchy horizon. There exists, in fact, a region of nonzero measure in the space of the parameters characterizing the solutions such that both instability and mass inflation are avoided. This is a new result concerning asymptotically flat space-times, not shared by the well-known solutions of General Relativity. Despite this fact, however, quantum back-reaction seems to produce a scalar curvature singularity there.

A. Fabbri

1996-07-04T23:59:59.000Z

325

The Seismic Analyzer: Interpreting and Illustrating 2D Seismic Data Daniel Patel, Christopher Giertsen, John Thurmond, John Gjelberg, and M. Eduard Groller, Member, IEEE  

E-Print Network [OSTI]

The Seismic Analyzer: Interpreting and Illustrating 2D Seismic Data Daniel Patel, Christopher for quickly interpreting and illustrating 2D slices of seismic volumetric reflection data. Searching for oil and gas involves creating a structural overview of seismic reflection data to identify hydrocarbon

326

Horizon surface gravity as 2d geodesic expansion  

E-Print Network [OSTI]

The surface gravity of any Killing horizon, in any spacetime dimension, can be interpreted as a local, two-dimensional expansion rate seen by freely falling observers when they cross the horizon. Any two-dimensional congruence of geodesics invariant under the Killing flow can be used to define this expansion, provided that the observers have unit Killing energy.

Ted Jacobson; Renaud Parentani

2008-08-13T23:59:59.000Z

327

Dynamics of the Solar Magnetic Network: Two-dimensional MHD Simulations  

E-Print Network [OSTI]

The aim of this work is to identify the physical processes that occur in the network and contribute to its dynamics and heating. We model the network as consisting of individual flux tubes with a non-potential field structure that are located in intergranular lanes. With a typical horizontal size of 200 km at the base of the photosphere, they expand upward and merge with their neighbors at a height of about 600 km. Above a height of approximately 1000 km the magnetic field starts to become uniform. Waves are generated in this medium by means of motions at the lower boundary. We focus on transverse driving, which generates both fast and slow waves within a flux tube and acoustic waves at the interface of the tube and the field-free medium. The acoustic waves at the interface are due to compression of the gas on one side of the flux tube and expansion on the other. These waves travel upward along the two sides of the (2D) flux tube and enter it, where they become longitudinal waves. For impulsive excitation with a time constant of 120 s, we find that a dominant feature is the creation of vortical motions that propagate upward. We have identified an efficient mechanism for the generation of longitudinal waves and shock formation in the chromospheric part of the flux concentration. We examine some broad implications of our results.

S. S. Hasan; A. A. van Ballegoiijen; W. Kalkofen; O. Steiner

2005-03-24T23:59:59.000Z

328

Two-Dimensional Hydrodynamic Models of Super Star Clusters with a Positive Star Formation Feedback  

E-Print Network [OSTI]

Using the hydrodynamic code ZEUS, we perform 2D simulations to determine the fate of the gas ejected by massive stars within super star clusters. It turns out that the outcome depends mainly on the mass and radius of the cluster. In the case of less massive clusters, a hot high velocity ($\\sim 1000$ km s$^{-1}$) stationary wind develops and the metals injected by supernovae are dispersed to large distances from the cluster. On the other hand, the density of the thermalized ejecta within massive and compact clusters is sufficiently large as to immediately provoke the onset of thermal instabilities. These deplete, particularly in the central densest regions, the pressure and the pressure gradient required to establish a stationary wind, and instead the thermally unstable parcels of gas are rapidly compressed, by a plethora of re-pressurizing shocks, into compact high density condensations. Most of these are unable to leave the cluster volume and thus accumulate to eventually feed further generations of star for...

Wünsch, R; Palous, J; Silich, S

2008-01-01T23:59:59.000Z

329

Two-dimensional spectral/statistical analysis of Marine magnetic data: implications for depth-to-magnetic source  

E-Print Network [OSTI]

T'A'0-DIMENSIONAL SPECTRAL/STATISTICAL ANAI. YSIS OF MARINE MAGNETIC DATA: IMPLICATIONS FOR DEPTH-TO-MAGNETIC SOURCE A Thesis by JEFFREY LEE SCHRULL Submitted to the Graduate College of Texas AdtM University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 1987 Major Subject: Geophysics TWO-DIMENSIONAL SPECTRAL/STATISTICAL ANALYSIS OF MARINE MAGNETIC DATA: IMPLICATIONS FOR DEPTH-TO-MAGNETIC SOURCE A Thesis JEFFREY LEE SCHRULL Approved as to style...

Schrull, Jeffrey Lee

1987-01-01T23:59:59.000Z

330

Coupled plasma waves in a system of two two-dimensional superlattices in the presence of a quantizing electric field  

SciTech Connect (OSTI)

The effect of a dc electric field on coupled plasma waves in a system of two two-dimensional super-lattices is studied. In the case of high temperatures, a dispersion relation is obtained and the fundamental and resonant modes of the plasma waves are numerically studied. The calculations are performed based on the quantum theory of plasma waves in the random phase approximation taking into account umklapp processes.

Glazov, S. Yu., E-mail: ser-glazov@yandex.ru; Kubrakova, E. S. [Volgograd State Social Pedagogical University (Russian Federation)] [Volgograd State Social Pedagogical University (Russian Federation); Mescheryakova, N. E. [Volgograd Institute of Business (Russian Federation)] [Volgograd Institute of Business (Russian Federation)

2013-10-15T23:59:59.000Z

331

Two-dimensional neutronic analysis of the TAMU Nuclear Science Center Reactor using transport and diffusion theory based codes  

E-Print Network [OSTI]

for the ACRR project at SNL were carried out utilizing one- and two-dimensional discrete or- dinates codes as documented in the project's quarterly progress reports. ' ' ] 3, 14, 1s, is, i 7, is Most calculations associated with the RERTR program performed... . . APPENDIX B. 2 ? LT CROSS SECTION FILE. . . . . . APPENDIX B. 3 ? HT CROSS SECTION FILE. . . . . . APPENDIX B. 4 - LP CROSS SECTION FILE. . . . . . APPENDIX B. 5 ? FP CROSS SECTION FILE. . . . . . 93 98 107 117 126 VITA . 135 LIST OF TABLES Table...

Davis, John Wesley

1988-01-01T23:59:59.000Z

332

Low-temperature scanning tunneling microscopy and transport measurements on adsorbate-induced two-dimensional electron systems  

SciTech Connect (OSTI)

We have performed not only magnetotransport measurements on two-dimensional electron systems (2DESs) formed at the cleaved surfaces of p-InAs but also observations of the surface morphology of the adsorbate atoms, which induced the 2DES at the surfaces of narrow band-gap semiconductors, with use of a scanning tunneling microscopy. The electron density of the 2DESs is compared to the atomic density of the isolated Ag adatoms on InAs surfaces.

Masutomi, Ryuichi; Triyama, Naotaka; Okamoto, Tohru [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2013-12-04T23:59:59.000Z

333

The calculation of the thermal properties of graphene under a magnetic field via the two-dimensional Dirac oscillator  

E-Print Network [OSTI]

In this paper, we show, by using the approach of effective mass, that the model of a two-dimensional Dirac oscillator can be used to describe the thermal properties of graphene under an uniform magnetic field. All thermal quantities of graphene, such as the free energy, the mean energy, the entropy and the specific heat, have been found by using an approach based on the zeta function.

Abdelmalek Boumali

2014-10-10T23:59:59.000Z

334

Study of two-dimensional transient cavity fields using the finite-difference time-domain technique  

SciTech Connect (OSTI)

This work is intended to be a study into the application of the finite-difference time-domain, or FD-TD technique, to some of the problems faced by designers of equipment used in modern accelerators. In particular it discusses using the FD-TD algorithm to study the field distribution of a simple two-dimensional cavity in both space and time. 18 refs.

Crisp, J.L.

1988-06-01T23:59:59.000Z

335

Closed loop engine control for regulating NOx emissions, using a two-dimensional fuel-air curve  

DOE Patents [OSTI]

An engine control strategy that ensures that NOx emissions from the engine will be maintained at an acceptable level. The control strategy is based on a two-dimensional fuel-air curve, in which air manifold pressure (AMP) is a function of fuel header pressure and engine speed. The control strategy provides for closed loop NOx adjustment to a base AMP value derived from the fuel-air curve.

Bourn, Gary D.; Smith, Jack A.; Gingrich, Jess W.

2007-01-30T23:59:59.000Z

336

Experiments with a nonstaggered, implicit, finite-difference operator for the two-dimensional free surface flow equations  

E-Print Network [OSTI]

Approved as to sty1e and content by: Chairman of Committee Member Member Member I Hea of Department December 1981 ABSTRACT Experiments with a Nonstaggered, Implicit, Finite-Difference Operator for the Two-Dimensional Free Surface Flow Equations... OF FIGURES ~Fi ure Schematic of Reid and Bodine [1968] scheme Schematic of Heaps [1969] scheme Schematic of Leendertse [1967] scheme Schematic of 1-D Preissmann operator . Theoretical amplitude portrait of Preissmann scheme - effect of e . ~pa e 10...

Hill, James Robert

1981-01-01T23:59:59.000Z

337

Second order symmetry-preserving conservative Lagrangian scheme for compressible Euler equations in two-dimensional cylindrical coordinates  

SciTech Connect (OSTI)

In applications such as astrophysics and inertial confinement fusion, there are many three-dimensional cylindrical-symmetric multi-material problems which are usually simulated by Lagrangian schemes in the two-dimensional cylindrical coordinates. For this type of simulation, a critical issue for the schemes is to keep spherical symmetry in the cylindrical coordinate system if the original physical problem has this symmetry. In the past decades, several Lagrangian schemes with such symmetry property have been developed, but all of them are only first order accurate. In this paper, we develop a second order cell-centered Lagrangian scheme for solving compressible Euler equations in cylindrical coordinates, based on the control volume discretizations, which is designed to have uniformly second order accuracy and capability to preserve one-dimensional spherical symmetry in a two-dimensional cylindrical geometry when computed on an equal-angle-zoned initial grid. The scheme maintains several good properties such as conservation for mass, momentum and total energy, and the geometric conservation law. Several two-dimensional numerical examples in cylindrical coordinates are presented to demonstrate the good performance of the scheme in terms of accuracy, symmetry, non-oscillation and robustness. The advantage of higher order accuracy is demonstrated in these examples.

Cheng, Juan, E-mail: cheng_juan@iapcm.ac.cn [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Shu, Chi-Wang, E-mail: shu@dam.brown.edu [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States)

2014-09-01T23:59:59.000Z

338

Suppression of electron magnetotunneling between parallel two-dimensional GaAs/InAs electron systems by the correlation interaction  

SciTech Connect (OSTI)

Magnetotunneling between two-dimensional GaAs/InAs electron systems in vertical resonant tunneling GaAs/InAs/AlAs heterostructures is studied. A new-type of singularity in the tunneling density of states, specifically a dip at the Fermi level, is found; this feature is drastically different from that observed previously for the case of tunneling between two-dimensional GaAs tunnel systems in terms of both the kind of functional dependence and the energy and temperature parameters. As before, this effect manifests itself in the suppression of resonant tunneling in a narrow range near zero bias voltage in a high magnetic field parallel to the current direction. Magnetic-field and temperature dependences of the effect's parameters are obtained; these dependences are compared with available theoretical and experimental data. The observed effect can be caused by a high degree of disorder in two-dimensional correlated electron systems as a result of the introduction of structurally imperfect strained InAs layers.

Khanin, Yu. N.; Vdovin, E. E., E-mail: vdov62@yandex.ru [Russian Academy of Sciences, Institute of Microelectronics Technology and High Purity Materials (Russian Federation); Makarovsky, O. [University of Nottingham, School of Physics and Astronomy (United Kingdom)] [University of Nottingham, School of Physics and Astronomy (United Kingdom); Henini, M. [University of Nottingham, School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Center (United Kingdom)] [University of Nottingham, School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Center (United Kingdom)

2013-09-15T23:59:59.000Z

339

Exploring size and state dynamics in CdSe quantum dots using two-dimensional electronic spectroscopy  

SciTech Connect (OSTI)

Development of optoelectronic technologies based on quantum dots depends on measuring, optimizing, and ultimately predicting charge carrier dynamics in the nanocrystal. In such systems, size inhomogeneity and the photoexcited population distribution among various excitonic states have distinct effects on electron and hole relaxation, which are difficult to distinguish spectroscopically. Two-dimensional electronic spectroscopy can help to untangle these effects by resolving excitation energy and subsequent nonlinear response in a single experiment. Using a filament-generated continuum as a pump and probe source, we collect two-dimensional spectra with sufficient spectral bandwidth to follow dynamics upon excitation of the lowest three optical transitions in a polydisperse ensemble of colloidal CdSe quantum dots. We first compare to prior transient absorption studies to confirm excitation-state-dependent dynamics such as increased surface-trapping upon excitation of hot electrons. Second, we demonstrate fast band-edge electron-hole pair solvation by ligand and phonon modes, as the ensemble relaxes to the photoluminescent state on a sub-picosecond time-scale. Third, we find that static disorder due to size polydispersity dominates the nonlinear response upon excitation into the hot electron manifold; this broadening mechanism stands in contrast to that of the band-edge exciton. Finally, we demonstrate excitation-energy dependent hot-carrier relaxation rates, and we describe how two-dimensional electronic spectroscopy can complement other transient nonlinear techniques.

Caram, Justin R.; Zheng, Haibin; Rolczynski, Brian S.; Griffin, Graham B.; Engel, Gregory S., E-mail: gsengel@uchicago.edu [Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Dahlberg, Peter D. [Graduate Program in the Biophysical Sciences, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)] [Graduate Program in the Biophysical Sciences, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Dolzhnikov, Dmitriy S.; Talapin, Dmitri V. [Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)] [Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)

2014-02-28T23:59:59.000Z

340

Synthesis, structures and properties of a family of four two-dimensional coordination polymers constructed from 5-hydroxyisophthalate  

SciTech Connect (OSTI)

Four 2D coordination polymers (CPs) with different structures containing the multifunctional ligand 5-hydroxyisophthalate (5-OH-BDC{sup 2?}), [Zn(5-OH-BDC)(btb)]·2H{sub 2}O (1), [Cd(5-OH-BDC)(btp)(H{sub 2}O)]·3H{sub 2}O (2), [Cd(5-OH-BDC)(bth){sub 2}(H{sub 2}O)]·H{sub 2}O (3) and [Pb(5-OH-BDC)]·H{sub 2}O (4) [btp=1, 3-bis(1,2,4-triazol-1-yl)propane, btb=1,4-bis(1,2,4-triazol-1-yl)butane, bth=1, 6-bis(1,2,4-triazol-1-yl)hexane] were obtained. 1–3 were synthesised hydrothermally, while 4 was obtained under ambient condition. The adjacent (2D?2D) polycatenated 2D layers of 1 polythread in a parallel manner to form an unusual 2D?3D polythreaded framework. 2 contains an undulated 2D (4, 4) network and further extends into an “embracing” double-layer structure through the C–H···? and ?···? stacking interactions. 3 exhibits a non-interpenetrating 2D (4, 4)-network. 4 exhibits a 2D double-layered binodal (4, 4)-net containing oblong nanochannels with symbol (4{sup 3}6{sup 3}){sub 2}. Reversible dehydration–rehydration is observed in 1, 2 and 4, which fall within the category of “recoverable collapsing” and “guest-induced re-formation” frameworks, while 3 exhibits irreversible dehydration–rehydration behaviour. The solid state fluorescent properties of 1–4 have been investigated. -- Graphical abstract: Among four 2D CPs reported, 1 is an unusual 2D?3D polythreaded framework. 4 exhibits 2D double-layered binodal (4, 4)-net containing nanochannels. Reversible dehydration–rehydration is observed in 1, 2 and 4. Highlights: • Four 2D CPs based on 5-hydroxyisophthalate with d{sup 10} and Pb(II) ions were reported. • 1 is an unusual 2D?3D polythreaded framework. • 4 shows a binodal (4, 4)-connected 2D double-layer network with nanochannels. • The materials 1, 2 and 4 show reversible dehydration–rehydration behaviours. • Solid state fluorescent properties were investigated.

Zhang, Kou-Lin, E-mail: klzhang@yzu.edu.cn [Key Laboratory of Environmental Material and Environmental Engineering of Jiangsu Province, College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Zhang, Jing-Bo; Jing, Chu-Yue; Zhang, Lei [Key Laboratory of Environmental Material and Environmental Engineering of Jiangsu Province, College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Walton, Richard I. [Department of Chemistry, University of Warwick, Coventry CV4 7AL (United Kingdom); Zhu, Peizhi, E-mail: pzzhu@yzu.edu.cn [Key Laboratory of Environmental Material and Environmental Engineering of Jiangsu Province, College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Ng, Seik Weng [Department of Chemistry, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2014-03-15T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Two-dimensional heterogeneous model for a reticulated-foam photocatalytic reactor  

SciTech Connect (OSTI)

A 2-D heterogeneous convection reaction model for a gas-solid lamp-in-tube annular photocatalytic reactor is presented. The catalyst (TiO{sub 2}) is supported on a reticulated-foam monolithic structure placed in the annular space between the UV lamp and the reactor wall. Mass balances for individual species are coupled through the reaction-rate expression that appears in the boundary condition at the fluid-solid interface in heterogeneous catalytic reactor models. The heterogeneous reaction rate is modeled using semiempirical Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetics with adsorption constants for various species. The local volumetric rate of energy absorption (LVREA) term in the rate expression was computed using a 3-D polychromatic radiation-field model. The overall system of nonlinear partial differential equations was solved using a combination of the Crank-Nicolson method and the globally convergent Newton-Raphson method. The apparent, average quantum yield in the LHHW kinetic rate form is the single adjustable parameter in the model. Isopropanol (IPA) was chosen as the test contaminant to conduct experimental performance measurements for model validation. Model-predicted radial and axial profiles for bulk and surface concentration reveal that the extent to which mass transport influences the operation of a photocatalytic reactor is determined largely by the local magnitude of the LVREA. Similitude in the scale-up of an annular lamp-in-tube heterogeneous photocatalytic reactor is achieved only when the dimensionless radial radiation profile, as well as corresponding magnitudes of a geometric number, the Peclet number, the Stanton number, and the photocatalytic analog of the Damkoehler number, are identical.

Changrani, R.G.; Raupp, G.B.

2000-04-01T23:59:59.000Z

342

Physica 65 (1973) 73-88 0 North-Holland Publishing Co. SURFACE TENSION IN THE TWO-DIMENSIONAL ISING MODEL  

E-Print Network [OSTI]

Physica 65 (1973) 73-88 0 North-Holland Publishing Co. SURFACE TENSION IN THE TWO-DIMENSIONAL ISING of surface tension between oppositely magnetised phases in the two-dimensional Ising model. With nearest?) defined and calculated exactly a surface tension. This was later shown by Fisher and Ferdinand5

Roma "La Sapienza", Università di

343

2d Affine XY-Spin Model/4d Gauge Theory Duality and Deconfinement  

SciTech Connect (OSTI)

We introduce a duality between two-dimensional XY-spin models with symmetry-breaking perturbations and certain four-dimensional SU(2) and SU(2) = Z{sub 2} gauge theories, compactified on a small spatial circle R{sup 1,2} x S{sup 1}, and considered at temperatures near the deconfinement transition. In a Euclidean set up, the theory is defined on R{sup 2} x T{sup 2}. Similarly, thermal gauge theories of higher rank are dual to new families of 'affine' XY-spin models with perturbations. For rank two, these are related to models used to describe the melting of a 2d crystal with a triangular lattice. The connection is made through a multi-component electric-magnetic Coulomb gas representation for both systems. Perturbations in the spin system map to topological defects in the gauge theory, such as monopole-instantons or magnetic bions, and the vortices in the spin system map to the electrically charged W-bosons in field theory (or vice versa, depending on the duality frame). The duality permits one to use the two-dimensional technology of spin systems to study the thermal deconfinement and discrete chiral transitions in four-dimensional SU(N{sub c}) gauge theories with n{sub f} {ge} 1 adjoint Weyl fermions.

Anber, Mohamed M.; Poppitz, Erich; /Toronto U.; Unsal, Mithat; /SLAC /Stanford U., Phys. Dept. /San Francisco State U.

2012-08-16T23:59:59.000Z

344

Determining Transition State Geometries in Liquids Using 2D-IR  

SciTech Connect (OSTI)

Many properties of chemical reactions are determined by the transition state connecting reactant and product, yet it is difficult to directly obtain any information about these short-lived structures in liquids. We show that two-dimensional infrared (2D-IR) spectroscopy can provide direct information about transition states by tracking the transformation of vibrational modes as a molecule crossed a transition state. We successfully monitored a simple chemical reaction, the fluxional rearrangement of Fe(CO)5, in which the exchange of axial and equatorial CO ligands causes an exchange of vibrational energy between the normal modes of the molecule. This energy transfer provides direct evidence regarding the time scale, transition state, and mechanism of the reaction.

Harris, Charles; Cahoon, James F.; Sawyer, Karma R.; Schlegel, Jacob P.; Harris, Charles B.

2007-12-11T23:59:59.000Z

345

Two-Dimensional Polaronic Behavior in the Binary Oxides m-HfO2 and m-ZrO2  

SciTech Connect (OSTI)

We demonstrate that the three-dimensional (3D) binary monoclinic oxides HfO{sub 2} and ZrO{sub 2} exhibit quasi-2D polaron localization and conductivity, which results from a small difference in the coordination of two oxygen sublattices in these materials. The transition between a 2D large polaron into a zero-dimensional small polaron state requires overcoming a small energetic barrier. These results demonstrate how a small asymmetry in the lattice structure can determine the qualitative character of polaron localization and significantly broaden the realm of quasi-2D polaron systems.

McKenna, K. P.; Wolf, M. J.; Shluger, A. L.; Lany, S.; Zunger, A.

2012-03-16T23:59:59.000Z

346

2-D color code quantum computation  

E-Print Network [OSTI]

We describe in detail how to perform universal fault-tolerant quantum computation on a 2-D color code, making use of only nearest neighbor interactions. Three defects (holes) in the code are used to represent logical qubits. Triple defect logical qubits are deformed into isolated triangular sections of color code to enable transversal implementation of all single logical qubit Clifford group gates. CNOT is implemented between pairs of triple defect logical qubits via braiding.

Austin G. Fowler

2011-01-10T23:59:59.000Z

347

2-D discrete element modeling of unconsolidated sandstones  

E-Print Network [OSTI]

developed in this thesis is compared to the results of triaxial tests performed in cylindrical core samples of unconsolidated sandstones saturated with heavy oil. The discrete element model treats the sand as a two dimensional assembly of particles...

Franquet Barbara, Javier Alejandro

2012-06-07T23:59:59.000Z

348

TWO-DIMENSIONAL STELLAR EVOLUTION CODE INCLUDING ARBITRARY MAGNETIC FIELDS. II. PRECISION IMPROVEMENT AND INCLUSION OF TURBULENCE AND ROTATION  

SciTech Connect (OSTI)

In the second paper of this series we pursue two objectives. First, in order to make the code more sensitive to small effects, we remove many approximations made in Paper I. Second, we include turbulence and rotation in the two-dimensional framework. The stellar equilibrium is described by means of a set of five differential equations, with the introduction of a new dependent variable, namely the perturbation to the radial gravity, that is found when the nonradial effects are considered in the solution of the Poisson equation. Following the scheme of the first paper, we write the equations in such a way that the two-dimensional effects can be easily disentangled. The key concept introduced in this series is the equipotential surface. We use the underlying cause-effect relation to develop a recurrence relation to calculate the equipotential surface functions for uniform rotation, differential rotation, rotation-like toroidal magnetic fields, and turbulence. We also develop a more precise code to numerically solve the two-dimensional stellar structure and evolution equations based on the equipotential surface calculations. We have shown that with this formulation we can achieve the precision required by observations by appropriately selecting the convergence criterion. Several examples are presented to show that the method works well. Since we are interested in modeling the effects of a dynamo-type field on the detailed envelope structure and global properties of the Sun, the code has been optimized for short timescales phenomena (down to 1 yr). The time dependence of the code has so far been tested exclusively to address such problems.

Li Linghuai; Sofia, Sabatino; Basu, Sarbani; Demarque, Pierre [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Ventura, Paolo [INAF, Osservatorio Astronomico di Roma, 00040 Monteporzio Catone (Italy); Penza, Valentina [Universita Di Roma 'Tor Vergata', Via Della Ricerca Scientifica 1, 00133 Roma (Italy); Bi Shaolan [Department of Astronomy, Beijing Normal University, Beijing 100875 (China)], E-mail: li@astro.yale.edu

2009-06-15T23:59:59.000Z

349

Two-Dimensional Stellar Evolution Code Including Arbitrary Magnetic Fields. II. Precision Improvement and Inclusion of Turbulence and Rotation  

E-Print Network [OSTI]

In the second paper of this series we pursue two objectives. First, in order to make the code more sensitive to small effects, we remove many approximations made in Paper I. Second, we include turbulence and rotation in the two-dimensional framework. The stellar equilibrium is described by means of a set of five differential equations, with the introduction of a new dependent variable, namely the perturbation to the radial gravity, that is found when the non-radial effects are considered in the solution of the Poisson equation; following the scheme of the first paper, we write the equations in such a way that the two-dimensional effects can be easily disentangled. The key concept introduced in this series is the equipotential surface. We use the underlying cause-effect relation to develop a recurrence relation to calculate the equipotential surface functions for uniform rotation, differential rotation, rotation-like toroidal magnetic fields and turbulence. We also develop a more precise code to numerically solve the two-dimensional stellar structure and evolution equations based on the equipotential surface calculations. We have shown that with this formulation we can achieve the precision required by observations by appropriately selecting the convergence criterion. Several examples are presented to show that the method works well. Since we are interested in modeling the effects of a dynamo-type field on the detailed envelope structure and global properties of the Sun, the code has been optimized for short timescales phenomena (down to 1 yr). The time dependence of the code has so far been tested exclusively to address such problems.

Linghuai Li; Sabatino Sofia; Paolo Ventura; Valentina Penza; Shaolan Bi; Sarbani Basu; Pierre Demarque

2008-10-27T23:59:59.000Z

350

A two-dimensional numerical simulation of shock-enhanced mixing in a rectangular scramjet flowfield with parallel hydrogen injection  

SciTech Connect (OSTI)

The effect of shock impingement on the mixing and combustion of a reacting shear-layer is numerically simulated. Hydrogen fuel is injected at sonic velocity behind a backward facing step in a direction parallel to a supersonic freestream vitiated with H{sub 2}O. The two-dimensional Navier-Stokes equations are solved and explicitly coupled to a chemistry package employing a global, two-step combustion model. The results show that shock impingement enhances the mixing and combustion. 17 refs.

Domel, N.D.; Thompson, D.S. (Texas Univ., Arlington (USA))

1991-01-01T23:59:59.000Z

351

One- and two-dimensional infrared spectroscopic studies of solution-phase homogeneous catalysis and spin-forbidden reactions  

SciTech Connect (OSTI)

Understanding chemical reactions requires the knowledge of the elementary steps of breaking and making bonds, and often a variety of experimental techniques are needed to achieve this goal. The initial steps occur on the femto- through picosecond time-scales, requiring the use of ultrafast spectroscopic methods, while the rate-limiting steps often occur more slowly, requiring alternative techniques. Ultrafast one and two-dimensional infrared and step-scan FTIR spectroscopies are used to investigate the photochemical reactions of four organometallic complexes. The analysis leads to a detailed understanding of mechanisms that are general in nature and may be applicable to a variety of reactions.

Sawyer, Karma Rae

2008-12-12T23:59:59.000Z

352

Two-dimensional imaging of gas-to-particle transition in flames by laser-induced nanoplasmas  

SciTech Connect (OSTI)

Two-dimensional imaging of gas/particle phase transition of metal oxides in their native high-temperature flow conditions, using laser-driven localized nanoplasmas, was obtained by utilizing the gap between the excitation energies of the gas and particle phases such that only the Ti atoms in the particle phase were selectively excited without detectable Bremsstrahlung background. These in situ images of the particle phase Ti distribution allow the quantitative visualization of the transition of the gas precursors to the nanoparticle phase across the flame sheet as well as diffusion of the particle concentration in the post-flame zone.

Zhang, Yiyang [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Li, Shuiqing, E-mail: lishuiqing@tsinghua.edu.cn; Ren, Yihua; Yao, Qiang [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Law, Chung K. [Center for Combustion Energy, Tsinghua University, Beijing 100084 (China); Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263 (United States)

2014-01-13T23:59:59.000Z

353

Finite-size effects on the phase diagram of difermion condensates in two-dimensional four-fermion interaction models  

SciTech Connect (OSTI)

We investigate finite-size effects on the phase structure of chiral and difermion condensates at finite temperature and density in the framework of the two-dimensional large-N Nambu-Jona-Lasinio model. We take into account size-dependent effects by making use of zeta-function and compactification methods. The thermodynamic potential and the gap equations for the chiral and difermion condensed phases are then derived in the mean-field approximation. Size-dependent critical lines separating the different phases are obtained considering antiperiodic boundary conditions for the spatial coordinate.

Abreu, L. M.; Malbouisson, J. M. C. [Instituto de Fisica, Universidade Federal da Bahia, 40210-340, Salvador, BA (Brazil); Malbouisson, A. P. C. [Centro Brasileiro de Pesquisas Fisicas, MCT, 22290-180, Rio de Janeiro, RJ (Brazil)

2011-01-15T23:59:59.000Z

354

Theory of two-dimensional macroscopic quantum tunneling in a Josephson junction coupled with an LC circuit  

E-Print Network [OSTI]

We investigate classical thermal activation (TA) and macroscopic quantum tunneling (MQT) for a Josephson junction coupled with an LC circuit theoretically. The TA and MQT escape rate are calculated analytically by taking into account the two-dimensional nature of the classical and quantum phase dynamics. We find that the MQT escape rate is largely suppressed by the coupling to the LC circuit. On the other hand, this coupling gives rise to slight reduction of the TA escape rate. These results are relevant for the interpretation of a recent experiment on the MQT and TA phenomena in grain boundary YBCO Josephson junctions.

Shiro Kawabata; Takeo Kato; Thilo Bauch

2009-12-17T23:59:59.000Z

355

A Fast Algorithm for Eye Detection Using Two-Dimensional CSP Akiko SUZUKI Tetsuya TAKIGUCHI Yasuo ARIKI  

E-Print Network [OSTI]

CSP A Fast Algorithm for Eye Detection Using Two-Dimensional CSP Akiko SUZUKI Tetsuya TAKIGUCHI Yasuo ARIKI 1. , CSP Crosspower-Spectrum Phase 2 [1] [2][3] CSP 2. W Ã? H I(x, y) w Ã? h T(i, j) R(x, y) R(x, y) (4) 3. CSP 1 CSP I(x, y) T(i, j) I(1, 2) = x,y I(x, y)e-j1x e-j2y (5) T(1, 2) = i,j T(i, j)e-j1

Takiguchi, Tetsuya

356

GBL-2D Version 1.0: a 2D geometry boolean library.  

SciTech Connect (OSTI)

This report describes version 1.0 of GBL-2D, a geometric Boolean library for 2D objects. The library is written in C++ and consists of a set of classes and routines. The classes primarily represent geometric data and relationships. Classes are provided for 2D points, lines, arcs, edge uses, loops, surfaces and mask sets. The routines contain algorithms for geometric Boolean operations and utility functions. Routines are provided that incorporate the Boolean operations: Union(OR), XOR, Intersection and Difference. A variety of additional analytical geometry routines and routines for importing and exporting the data in various file formats are also provided. The GBL-2D library was originally developed as a geometric modeling engine for use with a separate software tool, called SummitView [1], that manipulates the 2D mask sets created by designers of Micro-Electro-Mechanical Systems (MEMS). However, many other practical applications for this type of software can be envisioned because the need to perform 2D Boolean operations can arise in many contexts.

McBride, Cory L. (Elemental Technologies, American Fort, UT); Schmidt, Rodney Cannon; Yarberry, Victor R.; Meyers, Ray J. (Elemental Technologies, American Fort, UT)

2006-11-01T23:59:59.000Z

357

The Central Kiloparsec of Seyfert and Inactive Host Galaxies: a Comparison of Two-Dimensional Stellar and Gaseous Kinematics  

E-Print Network [OSTI]

We investigate the properties of the two-dimensional distribution and kinematics of ionised gas and stars in the central kiloparsecs of a matched sample of nearby active (Seyfert) and inactive galaxies, using the SAURON Integral Field Unit on the William Herschel Telescope. The ionised gas distributions show a range of low excitation regions such as star formation rings in Seyferts and inactive galaxies, and high excitation regions related to photoionisation by the AGN. The stellar kinematics of all galaxies in the sample show regular rotation patterns typical of disc-like systems, with kinematic axes which are well aligned with those derived from the outer photometry and which provide a reliable representation of the galactic line of nodes. After removal of the non-gravitational components due to e.g. AGN-driven outflows, the ionised gas kinematics in both the Seyfert and inactive galaxies are also dominated by rotation with global alignment between stars and gas in most galaxies. This result is consistent with previous findings from photometric studies that the large-scale light distribution of Seyfert hosts are similar to inactive hosts. However, fully exploiting the two-dimensional nature of our spectroscopic data, deviations from axisymmetric rotation in the gaseous velocity fields are identified that suggest the gaseous kinematics are more disturbed at small radii in the Seyfert galaxies compared with the inactive galaxies, providing a tentative link between nuclear gaseous streaming and nuclear activity.

Gaelle Dumas; Carole Mundell; Eric Emsellem; Neil Nagar

2007-05-29T23:59:59.000Z

358

ENERGY LANDSCAPE OF 2D FLUID FORMS  

SciTech Connect (OSTI)

The equilibrium states of 2D non-coarsening fluid foams, which consist of bubbles with fixed areas, correspond to local minima of the total perimeter. (1) The authors find an approximate value of the global minimum, and determine directly from an image how far a foam is from its ground state. (2) For (small) area disorder, small bubbles tend to sort inwards and large bubbles outwards. (3) Topological charges of the same sign repel while charges of opposite sign attract. (4) They discuss boundary conditions and the uniqueness of the pattern for fixed topology.

Y. JIANG; ET AL

2000-04-01T23:59:59.000Z

359

A generalized 2D pencil beam scaling algorithm for proton dose calculation in heterogeneous slab geometries  

SciTech Connect (OSTI)

Purpose: Pencil beam algorithms are commonly used for proton therapy dose calculations. Szymanowski and Oelfke ['Two-dimensional pencil beam scaling: An improved proton dose algorithm for heterogeneous media,' Phys. Med. Biol. 47, 3313-3330 (2002)] developed a two-dimensional (2D) scaling algorithm which accurately models the radial pencil beam width as a function of depth in heterogeneous slab geometries using a scaled expression for the radial kernel width in water as a function of depth and kinetic energy. However, an assumption made in the derivation of the technique limits its range of validity to cases where the input expression for the radial kernel width in water is derived from a local scattering power model. The goal of this work is to derive a generalized form of 2D pencil beam scaling that is independent of the scattering power model and appropriate for use with any expression for the radial kernel width in water as a function of depth. Methods: Using Fermi-Eyges transport theory, the authors derive an expression for the radial pencil beam width in heterogeneous slab geometries which is independent of the proton scattering power and related quantities. The authors then perform test calculations in homogeneous and heterogeneous slab phantoms using both the original 2D scaling model and the new model with expressions for the radial kernel width in water computed from both local and nonlocal scattering power models, as well as a nonlocal parameterization of Moliere scattering theory. In addition to kernel width calculations, dose calculations are also performed for a narrow Gaussian proton beam. Results: Pencil beam width calculations indicate that both 2D scaling formalisms perform well when the radial kernel width in water is derived from a local scattering power model. Computing the radial kernel width from a nonlocal scattering model results in the local 2D scaling formula under-predicting the pencil beam width by as much as 1.4 mm (21%) at the depth of the Bragg peak for a 220 MeV proton beam in homogeneous water. This translates into a 32% dose discrepancy for a 5 mm Gaussian proton beam. Similar trends were observed for calculations made in heterogeneous slab phantoms where it was also noted that errors tend to increase with greater beam penetration. The generalized 2D scaling model performs well in all situations, with a maximum dose error of 0.3% at the Bragg peak in a heterogeneous phantom containing 3 cm of hard bone. Conclusions: The authors have derived a generalized form of 2D pencil beam scaling which is independent of the proton scattering power model and robust to the functional form of the radial kernel width in water used for the calculations. Sample calculations made with this model show excellent agreement with expected values in both homogeneous water and heterogeneous phantoms.

Westerly, David C. [Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado 80045 (United States); Mo Xiaohu; DeLuca, Paul M. Jr. [Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705 (United States); Tome, Wolfgang A. [Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705 and Institute of Onco-Physics, Albert Einstein College of Medicine and Division of Medical Physics, Department of Radiation Oncology, Montefiore Medical Center, Bronx, New York 10461 (United States); Mackie, Thomas R. [Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705 and Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53792 (United States)

2013-06-15T23:59:59.000Z

360

Dissipative flows of 2D foams  

E-Print Network [OSTI]

We analyze the flow of a liquid foam between two plates separated by a gap of the order of the bubble size (2D foam). We concentrate on the salient features of the flow that are induced by the presence, in an otherwise monodisperse foam, of a single large bubble whose size is one order of magnitude larger than the average size. We describe a model suited for numerical simulations of flows of 2D foams made up of a large number of bubbles. The numerical results are successfully compared to analytical predictions based on scaling arguments and on continuum medium approximations. When the foam is pushed inside the cell at a controlled rate, two basically different regimes occur: a plug flow is observed at low flux whereas, above a threshold, the large bubble migrates faster than the mean flow. The detailed characterization of the relative velocity of the large bubble is the essential aim of the present paper. The relative velocity values, predicted both from numerical and from analytical calculations that are discussed here in great detail, are found to be in fair agreement with experimental results.

Isabelle Cantat; Renaud Delannay

2005-07-21T23:59:59.000Z

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361

Fabrication of Two-Dimensional Photonic Crystals in AlGaInP/GaInP Membranes by Inductively Coupled Plasma Etching  

E-Print Network [OSTI]

The fabrication process of two-dimensional photonic crystals in an AlGaInP/GaInP multi-quantum-well membrane structure is developed. The process includes high resolution electron-beam lithography, pattern transfer into ...

Chen, A.

362

A Three-Dimensional Ocean-Seaice-Carbon Cycle Model and its Coupling to a Two-Dimensional Atmospheric Model: Uses in Climate Change Studies  

E-Print Network [OSTI]

We describe the coupling of a three-dimensional ocean circulation model, with explicit thermodynamic seaice and ocean carbon cycle representations, to a two-dimensional atmospheric/land model. This coupled system has been ...

Dutkiewicz, Stephanie.

363

Liquid scintillator for 2D dosimetry for high-energy photon beams  

SciTech Connect (OSTI)

Complex radiation therapy techniques require dosimetric verification of treatment planning and delivery. The authors investigated a liquid scintillator (LS) system for application for real-time high-energy photon beam dosimetry. The system was comprised of a transparent acrylic tank filled with liquid scintillating material, an opaque outer tank, and a CCD camera. A series of images was acquired when the tank with liquid scintillator was irradiated with a 6 MV photon beam, and the light data measured with the CCD camera were filtered to correct for scattering of the optical light inside the liquid scintillator. Depth-dose and lateral profiles as well as two-dimensional (2D) dose distributions were found to agree with results from the treatment planning system. Further, the corrected light output was found to be linear with dose, dose rate independent, and is robust for single or multiple acquisitions. The short time needed for image acquisition and processing could make this system ideal for fast verification of the beam characteristics of the treatment machine. This new detector system shows a potential usefulness of the LS for 2D QA.

Poenisch, Falk; Archambault, Louis; Briere, Tina Marie; Sahoo, Narayan; Mohan, Radhe; Beddar, Sam; Gillin, Michael T. [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard., Unit 94, Houston, Texas 77030 (United States)

2009-05-15T23:59:59.000Z

364

A Cut-Cell Approach for 2D Cartesian Meshes that Preserves Orthogonal Grid Sweep Ordering  

SciTech Connect (OSTI)

In this paper, we present a cut-cell methodology for solving the two-dimensional neutral-particle transport equation on an orthogonal Cartesian grid. We allow the rectangular cell to be subdivided into two polygonal subcells. We ensure that this division (or cut) conserves the volumes of the materials in the subcells and we utilize a step-characteristics (SC) slice balance approach (SBA) to calculate the angular fluxes exiting the cell as well as the average scalar fluxes in each subcell. Solving the discrete ordinates transport equation on an arbitrary mesh has historically been difficult to parallelize while maintaining good parallel efficiency. However on Cartesian meshes, the KBA algorithm maintains good parallel efficiency using a direct solve. The ability to preserve this algorithm was a driving factor in the development of our cut-cell method. This method also provides a more accurate depiction of a material interface in a cell, which leads to more accurate solutions downstream of this cell. As a result, fewer spatial cells can be utilized, resulting in reduced memory requirements. We apply this approach in the 2D/3D discrete ordinates neutral-particle transport code Denovo, where we analyze a 2D 3 x 3 lattice of pincells. We show that, for eigenvalue problems, a significant increase in accuracy for a given mesh size is gained by utilizing the cut-cell, SC equations instead of the standard homogenized-cell, SC equations.

Jarrell, Joshua J [ORNL] [ORNL; Grove, Robert E [ORNL] [ORNL; Evans, Thomas M [ORNL] [ORNL

2011-01-01T23:59:59.000Z

365

Size-Dependent Detachment-Limited Decay Kinetics of Two-Dimensional TiN Islands on TiN(111)  

E-Print Network [OSTI]

Size-Dependent Detachment-Limited Decay Kinetics of Two-Dimensional TiN Islands on TiN(111) S kinetics of two-dimensional TiN adatom and vacancy islands on atomically smooth TiN(111) terraces. We numbers: 68.35.Md, 68.35.Fx, 68.37.Ef, 82.45.Mp B1-NaCl structure TiN is widely used as a hard wear

Gall, Daniel

366

Two-Dimensional Thin Layer Chromatography (2D-TLC) 1. Resuspend RNA pellet in 5 l ddH2O. Place at room temperature for 5-15 minutes. Use pipette tip  

E-Print Network [OSTI]

not damage surface of plate at origin. · Use Merck plates, 20 X 20 cm, pre-coated with cellulose, 0.1 mm, no indicator (from VWR). 5. Spot sample on chromatography plate at origin. Do 0.1 - 0.2 µl at a time. Dry with a gentle stream of filtered air across origin. Wait until spot is completely dry between applications

Aris, John P.

367

Splitting of 3d quaternion dimensions into 2d-sells and a "world screen technology"  

E-Print Network [OSTI]

A set of basic vectors locally describing metric properties of an arbitrary 2-dimensional (2D) surface is used for construction of fundamental algebraic objects having nilpotent and idempotent properties. It is shown that all possible linear combinations of the objects when multiplied behave as a set of hypercomples (in particular, quaternion) units; thus interior structure of the 3D space dimensions pointed by the vector units is exposed. Geometric representations of elementary surfaces (2D-sells) structuring the dimensions are studied in detail. Established mathematical link between a vector quaternion triad treated as a frame in 3D space and elementary 2D-sells prompts to raise an idea of "world screen" having 1/2 of a space dimension but adequately reflecting kinematical properties of an ensemble of 3D frames.

Alexander P. Yefremov

2012-02-14T23:59:59.000Z

368

A Two-Dimensional Approach to Evaluate the Scientific Production of Countries (Case Study: The Basic Sciences)  

E-Print Network [OSTI]

The quantity and quality of scientific output of the topmost 50 countries in the four basic sciences (agricultural and biological sciences, chemistry, mathematics, and physics and astronomy) are studied in the period of the recent 12 years (1996-2007). In order to rank the countries, a novel two-dimensional method is proposed, which is inspired by the H-index and other methods based on quality and quantity measures. The countries data are represented in a "quantity-quality diagram", and partitioned by a conventional statistical algorithm (k-means), into three clusters, members of which are rather the same in all of the basic sciences. The results offer a new perspective on the global positions of countries with regards to their scientific output.

Nejati, Ammar; 10.1007/s11192-009-0103-1

2013-01-01T23:59:59.000Z

369

The internal structure of a vortex in a two-dimensional superfluid with long healing length and its implications  

SciTech Connect (OSTI)

We analyze the motion of quantum vortices in a two-dimensional spinless superfluid within Popov’s hydrodynamic description. In the long healing length limit (where a large number of particles are inside the vortex core) the superfluid dynamics is determined by saddle points of Popov’s action, which, in particular, allows for weak solutions of the Gross–Pitaevskii equation. We solve the resulting equations of motion for a vortex moving with respect to the superfluid and find the reconstruction of the vortex core to be a non-analytic function of the force applied on the vortex. This response produces an anomalously large dipole moment of the vortex and, as a result, the spectrum associated with the vortex motion exhibits narrow resonances lying within the phonon part of the spectrum, contrary to traditional view.

Klein, Avraham [The Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 (Israel); Aleiner, Igor L., E-mail: aleiner@phys.columbia.edu [Physics Department, Columbia University, New York, NY 10027 (United States); Agam, Oded [The Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 (Israel); Physics Department, Columbia University, New York, NY 10027 (United States)

2014-07-15T23:59:59.000Z

370

Two-dimensional resonant magnetic excitation in BaFe1.84Co0.16As2  

SciTech Connect (OSTI)

Inelastic neutron scattering measurements on single crystals of superconducting BaFe1.84Co0.16As2 clearly reveal a magnetic excitation located at wavevectors (1/2 1/2 L) in tetragonal notation. The scattering is much broader in L than are spin waves observed in the parent compound BaFe2As2 indicating that the excitations in the superconducting material are more two-dimensional in nature. The excitation appears gapless for T > TC and becomes gapped on cooling below TC. The observed gap energy is approximately 9.6 meV corresponding to 5 kBTC which is remarkably similar to the canonical value for the resonance energy in the cuprates.

Lumsden, Mark D [ORNL; Christianson, Andrew D [ORNL; Parshall, Daniel [ORNL; Stone, Matthew B [ORNL; Nagler, Stephen E [ORNL; Mook Jr, Herbert A [ORNL; Lokshin, Konstantin A [ORNL; Egami, Takeshi [ORNL; Abernathy, Douglas L [ORNL; Goremychkin, E. A. [ISIS Facility, Rutherford Appleton Laboratory; Osborn, R. [Argonne National Laboratory (ANL); McGuire, Michael A [ORNL; Safa-Sefat, Athena [ORNL; Jin, Rongying [ORNL; Sales, Brian C [ORNL; Mandrus, David [ORNL

2009-01-01T23:59:59.000Z

371

A method for the frequency control in time-resolved two-dimensional gigahertz surface acoustic wave imaging  

SciTech Connect (OSTI)

We describe an extension of the time-resolved two-dimensional gigahertz surface acoustic wave imaging based on the optical pump-probe technique with periodic light source at a fixed repetition frequency. Usually such imaging measurement may generate and detect acoustic waves with their frequencies only at or near the integer multiples of the repetition frequency. Here we propose a method which utilizes the amplitude modulation of the excitation pulse train to modify the generation frequency free from the mentioned limitation, and allows for the first time the discrimination of the resulted upper- and lower-side-band frequency components in the detection. The validity of the method is demonstrated in a simple measurement on an isotropic glass plate covered by a metal thin film to extract the dispersion curves of the surface acoustic waves.

Kaneko, Shogo; Tomoda, Motonobu; Matsuda, Osamu, E-mail: omatsuda@eng.hokudai.ac.jp [Division of Applied Physics, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan)] [Division of Applied Physics, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan)

2014-01-15T23:59:59.000Z

372

Ground-state phase diagram of spin-(1/2) bosons in a two-dimensional optical lattice  

SciTech Connect (OSTI)

We study a two-species bosonic Hubbard model on a two-dimensional square lattice by means of quantum Monte Carlo simulations. In addition to the usual contact repulsive interactions between the particles, the Hamiltonian has an interconversion term which allows the transformation of two particles from one species to the other. The phases are characterized by their solid or superfluid properties and by their polarization, i.e., the difference in the populations. When interspecies interactions are smaller than the intraspecies ones, the system is unpolarized, whereas in the opposite case the system is unpolarized in even Mott insulator lobes and polarized in odd Mott lobes and also in the superfluid phase. We show that in the latter case the transition between the Mott insulator of total density 2 and the superfluid can be of either second or first order depending on the relative values of the interactions, whereas the transitions are continuous in all other cases.

Forges de Parny, L. de; Hebert, F. [INLN, Universite de Nice-Sophia Antipolis, CNRS, 1361 Route des Lucioles, 06560 Valbonne (France); Rousseau, V. G. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Scalettar, R. T. [Physics Department, University of California, Davis, California 95616 (United States); Batrouni, G. G. [INLN, Universite de Nice-Sophia Antipolis, CNRS, 1361 Route des Lucioles, 06560 Valbonne (France); Centre for Quantum Technologies, National University of Singapore, 2 Science Drive 3 Singapore 117542 (Singapore)

2011-08-01T23:59:59.000Z

373

Evidence for coupling between collective state and phonons in two-dimensional charge-density-wave systems  

SciTech Connect (OSTI)

We report on a Raman scattering investigation of the charge-density-wave (CDW), quasi two-dimensional rare-earth tri-tellurides RTe{sub 3} (R = La, Ce, Pr, Nd, Sm, Gd and Dy) at ambient pressure, and of LaTe{sub 3} and CeTe{sub 3} under externally applied pressure. The observed phonon peaks can be ascribed to the Raman active modes for both the undistorted as well as the distorted lattice in the CDW state by means of a first principles calculation. The latter also predicts the Kohn anomaly in the phonon dispersion, driving the CDW transition. The integrated intensity of the two most prominent modes scales as a characteristic power of the CDW-gap amplitude upon compressing the lattice, which provides clear evidence for the tight coupling between the CDW condensate and the vibrational modes.

Lavagnini, M.; /Zurich, ETH; Baldini, M.; /INFN, Rome; Sacchetti, A.; /Zurich, ETH; Castro, D.Di; /Zurich, ETH; Delley, B.; /PSI, Villigen; Monnier, R.; /Zurich, ETH; Chu, J.-H.; Ru, N.; Fisher, I.R.; /Stanford U., Geballe Lab.; Postorino, P.; /INFN, Rome; Degiorgi, L.; /Zurich, ETH

2010-02-15T23:59:59.000Z

374

Spin-polarized currents in the tunnel contact of a normal conductor and a two-dimensional topological insulator  

SciTech Connect (OSTI)

The spin filtering of electrons tunneling from the edge states of a two-dimensional topological insulator into a normal conductor under a magnetic field (external or induced due to proximity to a magnetic insulator) is studied. Calculations are performed for a tunnel contact of finite length between the topological insulator and an electronic multimode quantum strip. It is shown that the flow of tunneling electrons is split in the strip, so that spin-polarized currents arise in its left and right branches. These currents can be effectively controlled by the contact voltage and the chemical potential of the system. The presence of a magnetic field, which splits the spin subbands of the electron spectrum in the strip, gives rise to switching of the spin current between the strip branches.

Sukhanov, A. A., E-mail: AASukhanov@yandex.ru; Sablikov, V. A. [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Fryazino branch) (Russian Federation)] [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Fryazino branch) (Russian Federation)

2013-11-15T23:59:59.000Z

375

On the nonlinear stability of a quasi-two-dimensional drift kinetic model for ion temperature gradient turbulence  

E-Print Network [OSTI]

We study a quasi-two-dimensional electrostatic drift kinetic system as a model for near-marginal ion temperature gradient (ITG) driven turbulence. A proof is given of the nonlinear stability of this system under conditions of linear stability. This proof is achieved using a transformation that diagonalizes the linear dynamics and also commutes with nonlinear $E\\times B$ advection. For the case when linear instability is present, a corollary is found that forbids nonlinear energy transfer between appropriately defined sets of stable and unstable modes. It is speculated that this may explain the preservation of linear eigenmodes in nonlinear gyrokinetic simulations. Based on this property, a dimensionally reduced ($\\infty\\times\\infty \\rightarrow 1$) system is derived that may be useful for understanding dynamics around the critical gradient of Dimits.

Plunk, G G

2015-01-01T23:59:59.000Z

376

Yield drag in a two-dimensional foam flow around a circular obstacle: Effect of liquid fraction  

E-Print Network [OSTI]

We study the two-dimensional flow of foams around a circular obstacle within a long channel. In experiments, we confine the foam between liquid and glass surfaces. In simulations, we use a deterministic software, the Surface Evolver, for bubble details and a stochastic one, the extended Potts model, for statistics. We adopt a coherent definition of liquid fraction for all studied systems. We vary it in both experiments and simulations, and determine the yield drag of the foam, that is, the force exerted on the obstacle by the foam flowing at very low velocity. We find that the yield drag is linear over a large range of the ratio of obstacle to bubble size, and is independent of the channel width over a large range. Decreasing the liquid fraction, however, strongly increases the yield drag; we discuss and interpret this dependence.

Christophe Raufaste; B. Dollet; Simon Cox; Yi Jiang; François Graner

2007-07-09T23:59:59.000Z

377

Scaling behavior of universal pinch-off in two-dimensional foam Chin-Chang Kuo, and Michael Dennin  

E-Print Network [OSTI]

of significant study and are rele- vant to a wide range of applications such as sprays, droplet formation modes in fluids, the details of which depend on issues including the relative role of viscosity[1 with a relatively large viscosity [9]. For 2D inviscid fluids, simulations and analytic studies indicate

Dennin, Michael

378

Kinetic Monte Carlo Simulation ofKinetic Monte Carlo Simulation of TwoTwo--dimensional Semiconductordimensional Semiconductor  

E-Print Network [OSTI]

­ KMC 2D Growth Model ­ Growth Parameters Dependence of QDs Shape and Distribution · Temperature Parameters Dependence of QDs Shape and Distribution · Temperature ---- T · Surface coverage ---- c · Flux Melissa SunMelissa Sun Peter ChungPeter Chung Computer Modeling and Simulation Group The University

Pan, Ernie

379

2D Dirac Materials: From Graphene to Topological Insulators  

E-Print Network [OSTI]

2D Topological Insulators. . . . . . . . . . . . . . . . .structure for a topological insulator. The Dirac cone fallsband structure for topological insulators. With the Fermi

Teweldebrhan, Desalegne Bekuretsion

2011-01-01T23:59:59.000Z

380

Two-dimensional  

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381

2D 3D * iklee)@yonsei.ac.kr  

E-Print Network [OSTI]

1 2012 2D 3D * 0 , 1 , 2 0,2 1 ( 0 skrcjstk, 2 iklee)@yonsei.ac.kr 1 rinthel Science, Yonsei University. 1 Dept. of Information Media, The University of Suwon. 2D 3D . 2D - , 3D (Disparity) 3D . . 1. 3D 3D . 3D 3D [1

Lee, In-Kwon

382

2D dilaton-gravity from 5D Einstein equations  

E-Print Network [OSTI]

A semiclassical two-dimensional dilaton-gravity model is obtained by dimensional reduction of the spherically symmetric five-dimensional Einstein equations and used to investigate black hole evaporation. It is shown that this model prevents the formation of naked singularity and allows spacetime wormholes to contribute the process of formation and evaporation of black holes.

P. F. González-Díaz

1993-07-16T23:59:59.000Z

383

Magnonic band structure, complete bandgap, and collective spin wave excitation in nanoscale two-dimensional magnonic crystals  

SciTech Connect (OSTI)

We present the observation of a complete bandgap and collective spin wave excitation in two-dimensional magnonic crystals comprised of arrays of nanoscale antidots and nanodots, respectively. Considering that the frequencies dealt with here fall in the microwave band, these findings can be used for the development of suitable magnonic metamaterials and spin wave based signal processing. We also present the application of a numerical procedure, to compute the dispersion relations of spin waves for any high symmetry direction in the first Brillouin zone. The results obtained from this procedure have been reproduced and verified by the well established plane wave method for an antidot lattice, when magnetization dynamics at antidot boundaries are pinned. The micromagnetic simulation based method can also be used to obtain iso–frequency contours of spin waves. Iso–frequency contours are analogous of the Fermi surfaces and hence, they have the potential to radicalize our understanding of spin wave dynamics. The physical origin of bands, partial and full magnonic bandgaps have been explained by plotting the spatial distribution of spin wave energy spectral density. Although, unfettered by rigid assumptions and approximations, which afflict most analytical methods used in the study of spin wave dynamics, micromagnetic simulations tend to be computationally demanding. Thus, the observation of collective spin wave excitation in the case of nanodot arrays, which can obviate the need to perform simulations, may also prove to be valuable.

Kumar, D.; Barman, A., E-mail: abarman@bose.res.in [Thematic Unit of Excellence on Nanodevice Technology, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098 (India); K?os, J. W.; Krawczyk, M. [Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Pozna? 61-614 (Poland)

2014-01-28T23:59:59.000Z

384

Zero-energy states bound to a magnetic pi-flux vortex in a two-dimensional topological insulator  

E-Print Network [OSTI]

We show that the existence of a pair of zero-energy modes bound to a vortex carrying a pi-flux is a generic feature of the topologically non-trivial phase of the M-B model, which was introduced to describe the topological band insulator in HgTe quantum wells. We explicitly find the form of the zero-energy states of the corresponding Dirac equation, which contains a novel momentum-dependent mass term and describes a generic topological transition in a band insulator. The obtained modes are exponentially localized in the vortex-core, with the dependence of characteristic length on the parameters of the model matching the dependence extracted from a lattice version of the model. We consider in full generality the short-distance regularization of the vector potential of the vortex, and show that a particular choice yields the modes localized and simultaneously regular at the origin. Finally, we also discuss a realization of two-dimensional spin-charge separation through the vortex zero-modes.

Andrej Mesaros; Robert-Jan Slager; Jan Zaanen; Vladimir Juricic

2012-10-22T23:59:59.000Z

385

Trigonometrical sums connected with the chiral Potts model, Verlinde dimension formula, two-dimensional resistor network, and number theory  

SciTech Connect (OSTI)

We have recently developed methods for obtaining exact two-point resistance of the complete graph minus N edges. We use these methods to obtain closed formulas of certain trigonometrical sums that arise in connection with one-dimensional lattice, in proving Scott’s conjecture on permanent of Cauchy matrix, and in the perturbative chiral Potts model. The generalized trigonometrical sums of the chiral Potts model are shown to satisfy recursion formulas that are transparent and direct, and differ from those of Gervois and Mehta. By making a change of variables in these recursion formulas, the dimension of the space of conformal blocks of SU(2) and SO(3) WZW models may be computed recursively. Our methods are then extended to compute the corner-to-corner resistance, and the Kirchhoff index of the first non-trivial two-dimensional resistor network, 2×N. Finally, we obtain new closed formulas for variant of trigonometrical sums, some of which appear in connection with number theory. -- Highlights: • Alternative derivation of certain trigonometrical sums of the chiral Potts model are given. • Generalization of these trigonometrical sums satisfy recursion formulas. • The dimension of the space of conformal blocks may be computed from these recursions. • Exact corner-to-corner resistance, the Kirchhoff index of 2×N are given.

Chair, Noureddine, E-mail: n.chair@ju.edu.jo

2014-02-15T23:59:59.000Z

386

Strain and electric field induced electronic properties of two-dimensional hybrid bilayers of transition-metal dichalcogenides  

SciTech Connect (OSTI)

Tunability of the electronic properties of two-dimensional bilayer hetero structures of transition-metal dichalcogenides (i.e., MX{sub 2}-M?X?{sub 2} with (M, M??=?Mo, W; X, X??=?S, Se) is investigated. Application of both strain and electric field is found to modify the band gap and carrier effective mass in the hybrid bilayers considered. The calculated results based on density functional theory suggest that the tensile strain considerably changes the band gap of semiconducting bilayers; it makes the band gap to be indirect, and later initiates the semiconductor-to-metal transition. Application of the external electric fields, on the other hand, shows asymmetric variation in the band gap leading to the closure of the gap at about 0.5–1.0?V/Å. Tuning of the band gap and carrier effective mass in such a controlled manner makes the hybrid bilayers of transition metal dichalcogenides to be promising candidates for application in electronic devices at nanoscale.

Sharma, Munish, E-mail: munishsharmahpu@live.com, E-mail: pk-ahluwalia7@yahoo.com; Kumar, Ashok; Ahluwalia, P. K., E-mail: munishsharmahpu@live.com, E-mail: pk-ahluwalia7@yahoo.com [Department of Physics, Himachal Pradesh University, Shimla 171005 (India); Pandey, Ravindra [Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States)

2014-08-14T23:59:59.000Z

387

Apparatus and method for heterodyne-generated two-dimensional detector array using a single element detector  

DOE Patents [OSTI]

Apparatus and method for heterodyne-generated, two-dimensional detector array using a single detector. Synthetic-array heterodyne detection, permits a single-element optical detector to behave as though it were divided into an array of separate heterodyne detector elements. A fifteen-element synthetic array has successfully been experimentally realized on a single-element detector, permitting all of the array elements to be read out continuously and in parallel from one electrical connection. A CO.sub.2 laser and a single-element HgCdTe photodiode are employed. A different heterodyne local oscillator frequency is incident upon the spatially resolvable regions of the detector surface. Thus, different regions are mapped to different heterodyne beat frequencies. One can determine where the photons were incident on the detector surface even though a single electrical connection to the detector is used. This also prevents the destructive interference that occurs when multiple speckles are imaged (similar to spatial diversity), In coherent LIDAR this permits a larger field of view. An acoustooptic modulator generates the local oscillator frequencies and can achieve adequate spatial separation of optical frequencies of the order of a megahertz apart.

Strauss, Charlie E. (Santa Fe, NM)

1997-01-01T23:59:59.000Z

388

Apparatus and method for heterodyne-generated two-dimensional detector array using a single element detector  

DOE Patents [OSTI]

Apparatus and method are disclosed for heterodyne-generated, two-dimensional detector array using a single detector. Synthetic-array heterodyne detection, permits a single-element optical detector to behave as though it were divided into an array of separate heterodyne detector elements. A fifteen-element synthetic array has successfully been experimentally realized on a single-element detector, permitting all of the array elements to be read out continuously and in parallel from one electrical connection. A CO{sub 2} laser and a single-element HgCdTe photodiode are employed. A different heterodyne local oscillator frequency is incident upon the spatially resolvable regions of the detector surface. Thus, different regions are mapped to different heterodyne beat frequencies. One can determine where the photons were incident on the detector surface even though a single electrical connection to the detector is used. This also prevents the destructive interference that occurs when multiple speckles are imaged (similar to spatial diversity), In coherent LIDAR this permits a larger field of view. An acoustooptic modulator generates the local oscillator frequencies and can achieve adequate spatial separation of optical frequencies of the order of a megahertz apart. 4 figs.

Strauss, C.E.

1997-11-18T23:59:59.000Z

389

Long-time-tail Effects on Lyapunov Exponents of a Random, Two-dimensional Field-driven Lorentz Gas  

E-Print Network [OSTI]

We study the Lyapunov exponents for a moving, charged particle in a two-dimensional Lorentz gas with randomly placed, non-overlapping hard disk scatterers placed in a thermostatted electric field, $\\vec{E}$. The low density values of the Lyapunov exponents have been calculated with the use of an extended Lorentz-Boltzmann equation. In this paper we develop a method to extend these results to higher density, using the BBGKY hierarchy equations and extending them to include the additional variables needed for calculation of Lyapunov exponents. We then consider the effects of correlated collision sequences, due to the so-called ring events, on the Lyapunov exponents. For small values of the applied electric field, the ring terms lead to non-analytic, field dependent, contributions to both the positive and negative Lyapunov exponents which are of the form ${\\tilde{\\epsilon}}^{2} \\ln\\tilde{\\epsilon}$, where $\\tilde{\\epsilon}$ is a dimensionless parameter proportional to the strength of the applied field. We show that these non-analytic terms can be understood as resulting from the change in the collision frequency from its equilibrium value, due to the presence of the thermostatted field, and that the collision frequency also contains such non-analytic terms.

D. Panja; J. R. Dorfman; Henk van Beijeren

2000-02-09T23:59:59.000Z

390

Effect of phase transition on quantum transport in group-IV two-dimensional U-shape device  

SciTech Connect (OSTI)

The effect of phase-transition from the quantum-spin-hall to the band-insulator phase on the transport through a three-terminal U-shape spin-separator has been computationally investigated via non-equilibrium green function formalism. Two-dimensional group-IV elements have been comprehensively appraised as the device material. The device separates the unpolarized current injected at the source-terminal into nearly 100% spin-polarized currents of the opposite polarities at the two drain terminals. The phase-transition activated by the electric-field orthogonal to the device is shown to extensively influence the current magnitude and its spin-polarization, and the effect is stronger for materials with smaller intrinsic spin-orbit coupling. Moreover, the device length and the area under field are shown to critically affect the device characteristics on phase change. It is shown that the same device can be operated as a spin-filter by inducing phase-transition selectively in the channel. The results are important for designing spin-devices from Group-IV monolayers.

Sadi, Mohammad Abdullah; Gupta, Gaurav, E-mail: a0089293@nus.edu.sg; Liang, Gengchiau [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)

2014-10-21T23:59:59.000Z

391

A two-dimensional pseudospectral Hartree-Fock method for low-Z atoms in intense magnetic fields  

E-Print Network [OSTI]

The energy levels of the first few low-lying states of helium and lithium atoms in intense magnetic fields up to $\\approx 10^8-10^9$~T are calculated in this study. A pseudospectral method is employed for the computational procedure. The methodology involves computing the eigenvalues and eigenvectors of the generalized two-dimensional Hartree-Fock partial differential equations for these two- and three-electron systems in a self-consistent manner. The method exploits the natural symmetries of the problem without assumptions of any basis functions for expressing the wave functions of the electrons or the commonly employed adiabatic approximation. It is seen that the results obtained here for a few of the most tightly bound states of each of the atoms, helium and lithium, are in good agreement with findings elsewhere. In this regard, we report new data for two new states of lithium that have not been studied thus far in the literature. It is also seen that the pseudospectral method employed here is considerably more economical, from a computational point of view, than previously employed methods such as a finite-element based approach. The key enabling advantage of the method described here is the short computational times which are on the order of seconds for obtaining accurate results for heliumlike systems.

Anand Thirumalai; Jeremy S. Heyl

2014-04-24T23:59:59.000Z

392

Two-dimensional water waves in the presence of a freely floating body: conditions for the absence of trapped modes  

E-Print Network [OSTI]

The coupled motion is investigated for a mechanical system consisting of water and a body freely floating in it. Water occupies either a half-space or a layer of constant depth into which an infinitely long surface-piercing cylinder is immersed, thus allowing us to study two-dimensional modes. Under the assumption that the motion is of small amplitude near equilibrium, a linear setting is applicable and for the time-harmonic oscillations it reduces to a spectral problem with the frequency of oscillations as the spectral parameter. It is essential that one of the problem's relations is linear with respect to the parameter, whereas two others are quadratic with respect to it. Within this framework, it is shown that the total energy of the water motion is finite and the equipartition of energy holds for the whole system. On this basis, it is proved that no wave modes can be trapped provided their frequencies exceed a bound depending on cylinder's properties, whereas its geometry is subject to some restrictions and, in some cases, certain restrictions are imposed on the type of mode.

Nikolay Kuznetsov

2015-03-07T23:59:59.000Z

393

Using comprehensive two-dimensional gas chromatography to explore the geochemistry of the Santa Barbara oil seeps  

SciTech Connect (OSTI)

The development of comprehensive two-dimensional gas chromatography (GC x GC) has expanded the analytical window for studying complex mixtures like oil. Compared to traditional gas chromatography, this technology separates and resolves at least an order of magnitude more compounds, has a much larger signal to noise ratio, and sorts compounds based on their chemical class; hence, providing highly refined inventories of petroleum hydrocarbons in geochemical samples that was previously unattainable. In addition to the increased resolution afforded by GC x GC, the resulting chromatograms have been used to estimate the liquid vapor pressures, aqueous solubilities, octanol-water partition coefficients, and vaporization enthalpies of petroleum hydrocarbons. With these relationships, powerful and incisive analyses of phase-transfer processes affecting petroleum hydrocarbon mixtures in the environment are available. For example, GC x GC retention data has been used to quantitatively deconvolve the effects of phase transfer processes such as water washing and evaporation. In short, the positive attributes of GC x GC-analysis have led to a methodology that has revolutionized the analysis of petroleum hydrocarbons. Overall, this research has opened numerous fields of study on the biogeochemical "?genetics" (referred to as petroleomics) of petroleum samples in both subsurface and surface environments. Furthermore, these new findings have already been applied to the behavior of oil at other seeps as well, for petroleum exploration and oil spill studies.

Reddy, Christopher; Nelson, Robert

2013-03-27T23:59:59.000Z

394

Automated Classification of Stellar Spectra. II: Two-Dimensional Classification with Neural Networks and Principal Components Analysis  

E-Print Network [OSTI]

We investigate the application of neural networks to the automation of MK spectral classification. The data set for this project consists of a set of over 5000 optical (3800-5200 AA) spectra obtained from objective prism plates from the Michigan Spectral Survey. These spectra, along with their two-dimensional MK classifications listed in the Michigan Henry Draper Catalogue, were used to develop supervised neural network classifiers. We show that neural networks can give accurate spectral type classifications (sig_68 = 0.82 subtypes, sig_rms = 1.09 subtypes) across the full range of spectral types present in the data set (B2-M7). We show also that the networks yield correct luminosity classes for over 95% of both dwarfs and giants with a high degree of confidence. Stellar spectra generally contain a large amount of redundant information. We investigate the application of Principal Components Analysis (PCA) to the optimal compression of spectra. We show that PCA can compress the spectra by a factor of over 30 while retaining essentially all of the useful information in the data set. Furthermore, it is shown that this compression optimally removes noise and can be used to identify unusual spectra.

Coryn A. L. Bailer-Jones; Mike Irwin; Ted von Hippel

1998-03-05T23:59:59.000Z

395

Response to Halatek and Frey: Effective two-dimensional model does account for geometry sensing by self-organized proteins patterns  

E-Print Network [OSTI]

The Min proteins from Escherichia coli can self-organize into traveling waves on supported lipid bilayers. In Proc. Natl. Acad. Sci. USA 109, 15283 (2012) we showed that these waves are guided along the boundaries of membrane patches. We introduced an effective two-dimensional model reproducing the observed patterns. In arXiv:1403.5934v1, Jacob Halatek and Erwin Frey contest the ability of our effective two-dimensional model to describe the dynamics of Min proteins on patterned supported lipid bilayers. We thank Halatek and Frey for their interest in our work and for again highlighting the importance of dimensionality and geometry for pattern formation by the Min proteins. Here we reply in detail to the objections by Halatek and Frey and show that (1) our effective two-dimensional model reproduces the observed patterns on isolated patches and that (2) a three-dimensional version of our model produces similar patterns on square patches.

Mike Bonny; Jakob Schweizer; Martin Loose; Ingolf Mönch; Petra Schwille; Karsten Kruse

2014-06-05T23:59:59.000Z

396

2D grating simulation for X-ray phase-contrast and dark-field imaging with a Talbot interferometer  

SciTech Connect (OSTI)

Talbot interferometry is a recently developed and an extremely powerful X-ray phase-contrast imaging technique. Besides giving access to ultra-high sensitivity differential phase contrast images, it also provides the dark field image, which is a map of the scattering power of the sample. In this paper we investigate the potentialities of an improved version of the interferometer, in which two dimensional gratings are used instead of standard line grids. This approach allows to overcome the difficulties that might be encountered in the images produced by a one dimensional interferometer. Among these limitations there are the phase wrapping and quantitative phase retrieval problems and the directionality of the differential phase and dark-field signals. The feasibility of the 2D Talbot interferometer has been studied with a numerical simulation on the performances of its optical components under different circumstances. The gratings can be obtained either by an ad hoc fabrication of the 2D structures or by a superposition of two perpendicular linear grids. Through this simulation it has been possible to find the best parameters for a practical implementation of the 2D Talbot interferometer.

Zanette, Irene; Weitkamp, Timm [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble (France); David, Christian; Rutishauser, Simon [Paul Scherrer Insitute, 5232 Villigen PSI (Switzerland)

2010-04-06T23:59:59.000Z

397

The determination of the turbulent intensities in a transitional flow from a smooth to a rough wall with zero pressure gradient in a two-dimensional channel  

E-Print Network [OSTI]

THE DETERMINATION OF THE TURBULENT INTENSITIES IN A TRANSITIONAL FLOW FROM A SMOOTH TO A ROUGH WALL WITH ZERO PRESSURE GRADIENT IN A TWO-DIMENSIONAL CHANNEL A Thesis By Ol3AIDU I. ISLAM Submitted to the Graduate School of. tire Agricultural... WALL WITH ZERO PRESSURE GRADIENT IN A TWO DIMENSIONAL. GHANNEL A Thesis By OBAIDUL ISLAM Approved as to style and content by: F / F Ghairma p'f mm tg Head of Department May 1963 ACKNOWLEDGMENTS Grateful acknowledgment is made to the Texas...

Islam, Obaidul

1963-01-01T23:59:59.000Z

398

Two-dimensional equations of the surface harmonics method for solving problems of spatial neutron kinetics in square-lattice reactors  

SciTech Connect (OSTI)

Two-dimensional time-dependent finite-difference equations of the surface harmonics method (SHM) for the description of the neutron transport are derived for square-lattice reactors. These equations are implemented in the SUHAM-TD code. Verification of the derived equations and the developed code are performed by the example of known test problems, and the potential and efficiency of the SHM as applied to the solution of the time-dependent neutron transport equation in the diffusion approximation in two-dimensional geometry are demonstrated. These results show the substantial advantage of SHM over direct finite-difference modeling in computational costs.

Boyarinov, V. F., E-mail: boyarinov@dhtp.kiae.ru; Kondrushin, A. E., E-mail: kondrushin@yahoo.com; Fomichenko, P. A. [National Research Center Kurchatov Institute (Russian Federation)

2014-12-15T23:59:59.000Z

399

J. Phys. Chem. 1992,96, 6713-6116 6773 Spatial Bistabiiity of Two-Dimensional Turing Patterns in a Reaction-Diffusion System  

E-Print Network [OSTI]

J. Phys. Chem. 1992,96, 6713-6116 6773 Spatial Bistabiiity of Two-Dimensional Turing Patterns, Technical University of Budapest, H-I 521 Budapest, Hungary (Received: February 28, 1992) A Turing evidence of spatial bistabilitybetween different Turing structures. Introduction A Turing' (diffusion

Texas at Austin. University of

400

The 19th international conference on Electronic Properties of Two-Dimensional Systems (EP2DS19) and the 15th  

E-Print Network [OSTI]

2010 The 19th international conference on Electronic Properties of Two-Dimensional Systems (EP2DS19) and the 15th conference on Modulated Semiconductor Structures (MSS 15). July 25-29, 2011 Tallahassee, FL EP2DS19/MSS15Scope of conferences EP2DS emphasizes the fundamental physics, including transport

Weston, Ken

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Self-organization of bouncing oil drops: Two-dimensional lattices and spinning clusters Suzanne I. Lieber, Melissa C. Hendershott, Apichart Pattanaporkratana, and Joseph E. Maclennan  

E-Print Network [OSTI]

Self-organization of bouncing oil drops: Two-dimensional lattices and spinning clusters Suzanne I Received 16 October 2006; published 18 May 2007 Multiple oil drops bouncing on the surface of a vertically vibrating bath of the same oil exhibit self- organization behavior in two dimensions S. Protière, Y. Couder

Weeks, Eric R.

402

Two-dimensional protonic diffusion in a hydrogen-bonded compound CsOH . H2O, studied by solid state NMR  

E-Print Network [OSTI]

949 Two-dimensional protonic diffusion in a hydrogen-bonded compound CsOH . H2O, studied by solid césium hydroxide monohydrate CsH3O2 polycristallin révèle une diffusion protonique rapide dans ses phases hautes températures. Par mesure directe, la constante de diffusion est trouvée D = 1.2 10-5 exp(-1700/T

Paris-Sud XI, Université de

403

Bandgap Engineering in Disordered Graphene Two-dimensional atomic crystals attract attention due to their unique low-dimensional electron transport  

E-Print Network [OSTI]

Bandgap Engineering in Disordered Graphene ­Two-dimensional atomic crystals attract attention due-gap semiconductor graphene. The relativistic Dirac dispersion of electrons in graphene leads to an anomalous four large compared to electron Fermi wavelength. In high magnetic fields, the cleanest graphene samples

Weston, Ken

404

Analysis of two-dimensional high-energy photoelectron momentum distributions in the single ionization of atoms by intense laser pulses  

E-Print Network [OSTI]

, using longer pulses at lower intensities. The energy spectra above 4Up, where Up is the ponderomotive energy, have been found to vary rapidly with small changes in laser intensities 10,11 when laser pulseAnalysis of two-dimensional high-energy photoelectron momentum distributions in the single

Lin, Chii-Dong

405

ABSTRACT FINAL ID: SM13A-2029 TITLE: Particle-in-Cell Simulations of Two-dimensional Bernstein-Greene-Kruskal (BGK)  

E-Print Network [OSTI]

ABSTRACT FINAL ID: SM13A-2029 TITLE: Particle-in-Cell Simulations of Two-dimensional Bernstein, University of Alaska Fairbanks, Fairbanks, AK, United States. Title of Team: ABSTRACT BODY: Electrostatic with modulations having frequency of the order of electron cyclotron frequency. This work is supported

Ng, Chung-Sang

406

Two-Dimensional Interdigitated Pixel Detector for Energetic Particle Spectrometers Walter R. Cook III, Alan C. Cummings, Richard A. Mewaldt, Daniel L. Williams  

E-Print Network [OSTI]

Two-Dimensional Interdigitated Pixel Detector for Energetic Particle Spectrometers Walter R. Cook, such as those produced by solar flares. The detector is similar to previous types of silicon PIN detectors where samples of matter that can not be easily investigated by other means, including the solar corona

Fossum, Eric R.

407

hal-00090531,version4-6Jul2007 Yield drag in a two-dimensional foam flow around a circular obstacle  

E-Print Network [OSTI]

hal-00090531,version4-6Jul2007 Yield drag in a two-dimensional foam flow around a circular obstacle-dimensional flow of foams around a circular obstacle within a long channel. In experiments, we confine the foam between liquid and glass surfaces. In simulations, we use a deterministic software, the Surface Evolver

Boyer, Edmond

408

IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 48, NO. 2, FEBRUARY 2000 517 Image Classification by a Two-Dimensional Hidden  

E-Print Network [OSTI]

, the dependency in two dimensions is reflected simultaneously. The HMM parameters are estimated by the EM Foundation under NSF Grant MIP-931190 and by gifts from Hewlett-Packard, Inc. and SK Telecom, Inc, Stanford University, Stanford, CA 94305 USA (e-mail: jiali@isl.stanford.edu; zaalim

Li, Jia

409

Two-dimensional simulations of thermonuclear burn in ignition-scale inertial confinement fusion targets under compressed axial magnetic fields  

SciTech Connect (OSTI)

We report for the first time on full 2-D radiation-hydrodynamic implosion simulations that explore the impact of highly compressed imposed magnetic fields on the ignition and burn of perturbed spherical implosions of ignition-scale cryogenic capsules. Using perturbations that highly convolute the cold fuel boundary of the hotspot and prevent ignition without applied fields, we impose initial axial seed fields of 20–100 T (potentially attainable using present experimental methods) that compress to greater than 4 × 10{sup 4} T (400 MG) under implosion, thereby relaxing hotspot areal densities and pressures required for ignition and propagating burn by ?50%. The compressed field is high enough to suppress transverse electron heat conduction, and to allow alphas to couple energy into the hotspot even when highly deformed by large low-mode amplitudes. This might permit the recovery of ignition, or at least significant alpha particle heating, in submarginal capsules that would otherwise fail because of adverse hydrodynamic instabilities.

Perkins, L. J.; Logan, B. G.; Zimmerman, G. B.; Werner, C. J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2013-07-15T23:59:59.000Z

410

Tunable exchange bias-like effect in patterned hard-soft two-dimensional lateral composites with perpendicular magnetic anisotropy  

SciTech Connect (OSTI)

Patterned hard-soft 2D magnetic lateral composites have been fabricated by e-beam lithography plus dry etching techniques on sputter-deposited NdCo{sub 5} thin films with perpendicular magnetic anisotropy. Their magnetic behavior is strongly thickness dependent due to the interplay between out-of-plane anisotropy and magnetostatic energy. Thus, the spatial modulation of thicknesses leads to an exchange coupled system with hard/soft magnetic regions in which rotatable anisotropy of the thicker elements provides an extra tool to design the global magnetic behavior of the patterned lateral composite. Kerr microscopy studies (domain imaging and magneto-optical Kerr effect magnetometry) reveal that the resulting hysteresis loops exhibit a tunable exchange bias-like shift that can be switched on/off by the applied magnetic field.

Hierro-Rodriguez, A., E-mail: ahierro@fc.up.pt; Alvarez-Prado, L. M.; Martín, J. I.; Alameda, J. M. [Departamento de Física, Universidad de Oviedo, C/Calvo Sotelo S/N, 33007 Oviedo (Spain); Centro de Investigación en Nanomateriales y Nanotecnología—CINN (CSIC—Universidad de Oviedo—Principado de Asturias), Parque Tecnológico de Asturias, 33428 Llanera (Spain); Teixeira, J. M. [IN-IFIMUP, Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua Campo Alegre 687, 4169-007 Porto (Portugal); Vélez, M. [Departamento de Física, Universidad de Oviedo, C/Calvo Sotelo S/N, 33007 Oviedo (Spain)

2014-09-08T23:59:59.000Z

411

TRANSFER FROM GL(2, D) TO GSp(4) KIMBALL MARTIN  

E-Print Network [OSTI]

TRANSFER FROM GL(2, D) TO GSp(4) KIMBALL MARTIN Abstract. An integral criterion is known for when a cuspidal representation of GL(4) transfers to a generic representation of GSp(4). We review this transfer and discuss an integral criterion for when a representation of GL(2, D), D a quaternion algebra, transfers

Martin, Kimball

412

OECD/MCCI 2-D Core Concrete Interaction (CCI) tests : final report February 28, 2006.  

SciTech Connect (OSTI)

Although extensive research has been conducted over the last several years in the areas of Core-Concrete Interaction (CCI) and debris coolability, two important issues warrant further investigation. The first issue concerns the effectiveness of water in terminating a CCI by flooding the interacting masses from above, thereby quenching the molten core debris and rendering it permanently coolable. This safety issue was investigated in the EPRI-sponsored Melt Attack and Coolability Experiments (MACE) program. The approach was to conduct large scale, integral-type reactor materials experiments with core melt masses ranging up to two metric tons. These experiments provided unique, and for the most part repeatable, indications of heat transfer mechanism(s) that could provide long term debris cooling. However, the results did not demonstrate definitively that a melt would always be completely quenched. This was due to the fact that the crust anchored to the test section sidewalls in every test, which led to melt/crust separation, even at the largest test section lateral span of 1.20 m. This decoupling is not expected for a typical reactor cavity, which has a span of 5-6 m. Even though the crust may mechanically bond to the reactor cavity walls, the weight of the coolant and the crust itself is expected to periodically fracture the crust and restore contact with the melt. Although crust fracturing does not ensure that coolability will be achieved, it nonetheless provides a pathway for water to recontact the underlying melt, thereby allowing other debris cooling mechanisms to proceed. A related task of the current program, which is not addressed in this particular report, is to measure crust strength to check the hypothesis that a corium crust would not be strong enough to sustain melt/crust separation in a plant accident. The second important issue concerns long-term, two-dimensional concrete ablation by a prototypic core oxide melt. As discussed by Foit the existing reactor material database for dry cavity conditions is solely one-dimensional. Although the MACE Scoping Test was carried out with a two-dimensional concrete cavity, the interaction was flooded soon after ablation was initiated to investigate debris coolability. Moreover, due to the scoping nature of this test, the apparatus was minimally instrumented and therefore the results are of limited value from the code validation viewpoint. Aside from the MACE program, the COTELS test series also investigated 2-D CCI under flooded cavity conditions. However, the input power density for these tests was quite high relative to the prototypic case. Finally, the BETA test series provided valuable data on 2-D core concrete interaction under dry cavity conditions, but these tests focused on investigating the interaction of the metallic (steel) phase with concrete. Due to these limitations, there is significant uncertainty in the partition of energy dissipated for the ablation of concrete in the lateral and axial directions under dry cavity conditions for the case of a core oxide melt. Accurate knowledge of this 'power split' is important in the evaluation of the consequences of an ex-vessel severe accident; e.g., lateral erosion can undermine containment structures, while axial erosion can penetrate the basemat, leading to ground contamination and/or possible containment bypass. As a result of this uncertainty, there are still substantial differences among computer codes in the prediction of 2-D cavity erosion behavior under both wet and dry cavity conditions. In light of the above issues, the OECD-sponsored Melt Coolability and Concrete Interaction (MCCI) program was initiated at Argonne National Laboratory. The project conducted reactor materials experiments and associated analysis to achieve the following technical objectives: (1) resolve the ex-vessel debris coolability issue through a program that focused on providing both confirmatory evidence and test data for the coolability mechanisms identified in MACE integral effects tests, and (2) address remaining uncertainties relat

Farmer, M. T.; Lomperski, S.; Kilsdonk, D. J.; Aeschlimann, R. W.; Basu, S. (Nuclear Engineering Division); (NRC)

2011-05-23T23:59:59.000Z

413

The simulation of 3D microcalcification clusters in 2D digital mammography and breast tomosynthesis  

SciTech Connect (OSTI)

Purpose: This work proposes a new method of building 3D models of microcalcification clusters and describes the validation of their realistic appearance when simulated into 2D digital mammograms and into breast tomosynthesis images. Methods: A micro-CT unit was used to scan 23 breast biopsy specimens of microcalcification clusters with malignant and benign characteristics and their 3D reconstructed datasets were segmented to obtain 3D models of microcalcification clusters. These models were then adjusted for the x-ray spectrum used and for the system resolution and simulated into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. Six radiologists were asked to distinguish between 40 real and 40 simulated clusters of microcalcifications in two separate studies on 2D mammography and tomosynthesis datasets. Receiver operating characteristic (ROC) analysis was used to test the ability of each observer to distinguish between simulated and real microcalcification clusters. The kappa statistic was applied to assess how often the individual simulated and real microcalcification clusters had received similar scores (''agreement'') on their realistic appearance in both modalities. This analysis was performed for all readers and for the real and the simulated group of microcalcification clusters separately. ''Poor'' agreement would reflect radiologists' confusion between simulated and real clusters, i.e., lesions not systematically evaluated in both modalities as either simulated or real, and would therefore be interpreted as a success of the present models. Results: The area under the ROC curve, averaged over the observers, was 0.55 (95% confidence interval [0.44, 0.66]) for the 2D study, and 0.46 (95% confidence interval [0.29, 0.64]) for the tomosynthesis study, indicating no statistically significant difference between real and simulated lesions (p > 0.05). Agreement between allocated lesion scores for 2D mammography and those for the tomosynthesis series was poor. Conclusions: The realistic appearance of the 3D models of microcalcification clusters, whether malignant or benign clusters, was confirmed for 2D digital mammography images and the breast tomosynthesis datasets; this database of clusters is suitable for use in future observer performance studies related to the detectability of microcalcification clusters. Such studies include comparing 2D digital mammography to breast tomosynthesis and comparing different reconstruction algorithms.

Shaheen, Eman; Van Ongeval, Chantal; Zanca, Federica; Cockmartin, Lesley; Marshall, Nicholas; Jacobs, Jurgen; Young, Kenneth C.; Dance, David R.; Bosmans, Hilde [Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium); National Coordinating Centre for the Physics of Mammography, Royal Surrey County Hospital, Guildford, GU2 7XX (United Kingdom); Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium)

2011-12-15T23:59:59.000Z

414

2D surface temperature measurement of plasma facing components with modulated active pyrometry  

SciTech Connect (OSTI)

In nuclear fusion devices, such as Tore Supra, the plasma facing components (PFC) are in carbon. Such components are exposed to very high heat flux and the surface temperature measurement is mandatory for the safety of the device and also for efficient plasma scenario development. Besides this measurement is essential to evaluate these heat fluxes for a better knowledge of the physics of plasma-wall interaction, it is also required to monitor the fatigue of PFCs. Infrared system (IR) is used to manage to measure surface temperature in real time. For carbon PFCs, the emissivity is high and known (? ? 0.8), therefore the contribution of the reflected flux from environment and collected by the IR cameras can be neglected. However, the future tokamaks such as WEST and ITER will be equipped with PFCs in metal (W and Be/W, respectively) with low and variable emissivities (? ? 0.1–0.4). Consequently, the reflected flux will contribute significantly in the collected flux by IR camera. The modulated active pyrometry, using a bicolor camera, proposed in this paper allows a 2D surface temperature measurement independently of the reflected fluxes and the emissivity. Experimental results with Tungsten sample are reported and compared with simultaneous measurement performed with classical pyrometry (monochromatic and bichromatic) with and without reflective flux demonstrating the efficiency of this method for surface temperature measurement independently of the reflected flux and the emissivity.

Amiel, S.; Loarer, T.; Pocheau, C.; Roche, H.; Gauthier, E.; Aumeunier, M.-H.; Courtois, X.; Jouve, M.; Balorin, C.; Moncada, V. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Le Niliot, C.; Rigollet, F. [Aix-Marseille Univ, IUSTI, UMR CNRS 7343, F-13453 Marseille (France)

2014-10-15T23:59:59.000Z

415

Comparison of 2D and 3D gamma analyses  

SciTech Connect (OSTI)

Purpose: As clinics begin to use 3D metrics for intensity-modulated radiation therapy (IMRT) quality assurance, it must be noted that these metrics will often produce results different from those produced by their 2D counterparts. 3D and 2D gamma analyses would be expected to produce different values, in part because of the different search space available. In the present investigation, the authors compared the results of 2D and 3D gamma analysis (where both datasets were generated in the same manner) for clinical treatment plans. Methods: Fifty IMRT plans were selected from the authors’ clinical database, and recalculated using Monte Carlo. Treatment planning system-calculated (“evaluated dose distributions”) and Monte Carlo-recalculated (“reference dose distributions”) dose distributions were compared using 2D and 3D gamma analysis. This analysis was performed using a variety of dose-difference (5%, 3%, 2%, and 1%) and distance-to-agreement (5, 3, 2, and 1 mm) acceptance criteria, low-dose thresholds (5%, 10%, and 15% of the prescription dose), and data grid sizes (1.0, 1.5, and 3.0 mm). Each comparison was evaluated to determine the average 2D and 3D gamma, lower 95th percentile gamma value, and percentage of pixels passing gamma. Results: The average gamma, lower 95th percentile gamma value, and percentage of passing pixels for each acceptance criterion demonstrated better agreement for 3D than for 2D analysis for every plan comparison. The average difference in the percentage of passing pixels between the 2D and 3D analyses with no low-dose threshold ranged from 0.9% to 2.1%. Similarly, using a low-dose threshold resulted in a difference between the mean 2D and 3D results, ranging from 0.8% to 1.5%. The authors observed no appreciable differences in gamma with changes in the data density (constant difference: 0.8% for 2D vs 3D). Conclusions: The authors found that 3D gamma analysis resulted in up to 2.9% more pixels passing than 2D analysis. It must be noted that clinical 2D versus 3D datasets may have additional differences—for example, if 2D measurements are made with a different dosimeter than 3D measurements. Factors such as inherent dosimeter differences may be an important additional consideration to the extra dimension of available data that was evaluated in this study.

Pulliam, Kiley B.; Huang, Jessie Y.; Howell, Rebecca M.; Followill, David; Kry, Stephen F., E-mail: sfkry@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States); Bosca, Ryan [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States)] [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States); O’Daniel, Jennifer [Department of Radiation Oncology, Duke University, Durham, North Carolina 27705 (United States)] [Department of Radiation Oncology, Duke University, Durham, North Carolina 27705 (United States)

2014-02-15T23:59:59.000Z

416

Understanding the two-dimensional ionization structure in luminous infrared galaxies. A near-IR integral field spectroscopy perspective  

E-Print Network [OSTI]

We investigate the 2D excitation structure of the ISM in a sample of LIRGs and Seyferts using near-IR IFS. This study extends to the near-IR the well-known optical and mid-IR emission line diagnostics used to classify activity in galaxies. Based on the spatially resolved spectroscopy of prototypes, we identify in the [FeII]1.64/Br$\\gamma$ - H_2 1-0S(1)/Br$\\gamma$ plane regions dominated by the different heating sources, i.e. AGNs, young MS massive stars, and evolved stars i.e. supernovae. The ISM in LIRGs occupy a wide region in the near-IR diagnostic plane from -0.6 to +1.5 and from -1.2 to +0.8 (in log units) for the [FeII]/Br$\\gamma$ and H_2/Br$\\gamma$ line ratios, respectively. The corresponding median(mode) ratios are +0.18(0.16) and +0.02(-0.04). Seyferts show on average larger values by factors ~2.5 and ~1.4 for the [FeII]/Br$\\gamma$ and H_2/Br$\\gamma$ ratios, respectively. New areas and relations in the near-IR diagnostic plane are defined for the compact, high surface brightness regions dominated by ...

Colina, Luis; Arribas, Santiago; Riffel, Rogerio; Riffel, Rogemar A; Rodriguez-Ardila, Alberto; Pastoriza, Miriani; Storchi-Bergmann, Thaisa; Alonso-Herrero, Almudena; Sales, Dinalva

2015-01-01T23:59:59.000Z

417

Automatic recovery of missing amplitudes and phases in tilt-limited electron crystallography of two-dimensional crystals  

SciTech Connect (OSTI)

Electron crystallography of 2D protein crystals provides a powerful tool for the determination of membrane protein structure. In this method, data is acquired in the Fourier domain as randomly sampled, uncoupled, amplitudes and phases. Due to physical constraints on specimen tilting, those Fourier data show a vast un-sampled ''missing cone'' of information, producing resolution loss in the direction perpendicular to the membrane plane. Based on the flexible language of projection onto sets, we provide a full solution for these problems with a projective constraint optimization algorithm that, for sufficiently oversampled data, produces complete recovery of unmeasured data in the missing cone. We apply this method to an experimental data set of Bacteriorhodopsin and show that, in addition to producing superior results compared to traditional reconstruction methods, full, reproducible, recovery of the missing cone from noisy data is possible. Finally, we present an automatic implementation of the refinement routine as open source, freely distributed, software that will be included in our 2dx software package.

Gipson, Bryant R.; Stahlberg, Henning [Center for Cellular Imaging and Nano Analytics (C-CINA), Biozentrum, University Basel, WRO-1058 Mattenstrasse 26, CH-4058 Basel (Switzerland); Masiel, Daniel J.; Browning, Nigel D. [Department of Chemical Engineering and Materials Sciences, University of California at Davis, Davis, California 95616 (United States); Spence, John [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States); Mitsuoka, Kaoru [Biomedicinal Information Research Center (BIRC), National Institute of Advanced Industrial Science and Technology (AIST), 2-3-26, Aomi, Koto-ku, Tokyo 135-0064 (Japan)

2011-07-15T23:59:59.000Z

418

High precision two-dimensional strain mapping in semiconductor devices using nanobeam electron diffraction in the transmission electron microscope  

SciTech Connect (OSTI)

A classical method used to characterize the strain in modern semiconductor devices is nanobeam diffraction (NBD) in the transmission electron microscope. One challenge for this method lies in the fact that the smaller the beam becomes, the more difficult it becomes to analyze the resulting diffraction spot pattern. We show that a carefully designed fitting algorithm enables us to reduce the sampling area for the diffraction patterns on the camera chip dramatically (?1/16) compared to traditional settings without significant loss of precision. The resulting lower magnification of the spot pattern permits the presence of an annular dark field detector, which in turn makes the recording of images for drift correction during NBD acquisition possible. Thus, the reduced sampling size allows acquisition of drift corrected NBD 2D strain maps of up to 3000 pixels while maintaining a precision of better than 0.07%. As an example, we show NBD strain maps of a modern field effect transistor (FET) device. A special filtering feature used in the analysis makes it is possible to measure strain in silicon devices even in the presence of other crystalline materials covering the probed area, which is important for the characterization of the next generation of devices (Fin-FETs).

Baumann, Frieder H., E-mail: fhbauman@us.ibm.com [IBM Microelectronics Division, 2070 Route 52, Hopewell Junction, New York 12533 (United States)

2014-06-30T23:59:59.000Z

419

Compact and high-particle-flux thermal-lithium-beam probe system for measurement of two-dimensional electron density profile  

SciTech Connect (OSTI)

A compact and high-particle-flux thermal-lithium-beam source for two-dimensional measurement of electron density profiles has been developed. The thermal-lithium-beam oven is heated by a carbon heater. In this system, the maximum particle flux of the thermal lithium beam was ?4 × 10{sup 19} m{sup ?2} s{sup ?1} when the temperature of the thermal-lithium-beam oven was 900 K. The electron density profile was evaluated in the small tokamak device HYBTOK-II. The electron density profile was reconstructed using the thermal-lithium-beam probe data and this profile was consistent with the electron density profile measured with a Langmuir electrostatic probe. We confirm that the developed thermal-lithium-beam probe can be used to measure the two-dimensional electron density profile with high time and spatial resolutions.

Shibata, Y., E-mail: shibata.yoshihide@jaea.go.jp; Manabe, T.; Ohno, N.; Takagi, M. [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Kajita, S. [EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Tsuchiya, H.; Morisaki, T. [National Institute for Fusion Science, Oroshi, Toki, Gifu 509-5292 (Japan)

2014-09-15T23:59:59.000Z

420

The Branching of Graphs in 2-d Quantum Gravity  

E-Print Network [OSTI]

The branching ratio is calculated for three different models of 2d gravity, using dynamical planar phi-cubed graphs. These models are pure gravity, the D=-2 Gaussian model coupled to gravity and the single spin Ising model coupled to gravity. The ratio gives a measure of how branched the graphs dominating the partition function are. Hence it can be used to estimate the location of the branched polymer phase for the multiple Ising model coupled to 2d gravity.

M. G. Harris

1996-07-16T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Computational Study and Analysis of Structural Imperfections in 1D and 2D Photonic Crystals  

SciTech Connect (OSTI)

Dielectric reflectors that are periodic in one or two dimensions, also known as 1D and 2D photonic crystals, have been widely studied for many potential applications due to the presence of wavelength-tunable photonic bandgaps. However, the unique optical behavior of photonic crystals is based on theoretical models of perfect analogues. Little is known about the practical effects of dielectric imperfections on their technologically useful optical properties. In order to address this issue, a finite-difference time-domain (FDTD) code is employed to study the effect of three specific dielectric imperfections in 1D and 2D photonic crystals. The first imperfection investigated is dielectric interfacial roughness in quarter-wave tuned 1D photonic crystals at normal incidence. This study reveals that the reflectivity of some roughened photonic crystal configurations can change up to 50% at the center of the bandgap for RMS roughness values around 20% of the characteristic periodicity of the crystal. However, this reflectivity change can be mitigated by increasing the index contrast and/or the number of bilayers in the crystal. In order to explain these results, the homogenization approximation, which is usually applied to single rough surfaces, is applied to the quarter-wave stacks. The results of the homogenization approximation match the FDTD results extremely well, suggesting that the main role of the roughness features is to grade the refractive index profile of the interfaces in the photonic crystal rather than diffusely scatter the incoming light. This result also implies that the amount of incoherent reflection from the roughened quarterwave stacks is extremely small. This is confirmed through direct extraction of the amount of incoherent power from the FDTD calculations. Further FDTD studies are done on the entire normal incidence bandgap of roughened 1D photonic crystals. These results reveal a narrowing and red-shifting of the normal incidence bandgap with increasing RMS roughness. Again, the homogenization approximation is able to predict these results. The problem of surface scratches on 1D photonic crystals is also addressed. Although the reflectivity decreases are lower in this study, up to a 15% change in reflectivity is observed in certain scratched photonic crystal structures. However, this reflectivity change can be significantly decreased by adding a low index protective coating to the surface of the photonic crystal. Again, application of homogenization theory to these structures confirms its predictive power for this type of imperfection as well. Additionally, the problem of a circular pores in 2D photonic crystals is investigated, showing that almost a 50% change in reflectivity can occur for some structures. Furthermore, this study reveals trends that are consistent with the 1D simulations: parameter changes that increase the absolute reflectivity of the photonic crystal will also increase its tolerance to structural imperfections. Finally, experimental reflectance spectra from roughened 1D photonic crystals are compared to the results predicted computationally in this thesis. Both the computed and experimental spectra correlate favorably, validating the findings presented herein.

K.R. Maskaly

2005-06-01T23:59:59.000Z

422

OECD 2-D Core Concrete Interaction (CCI) tests : CCI-2 test plan, Rev. 0 January 31, 2004.  

SciTech Connect (OSTI)

The Melt Attack and Coolability Experiments (MACE) program addressed the issue of the ability of water to cool and thermally stabilize a molten core-concrete interaction when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. As a follow-on program to MACE, The Melt Coolability and Concrete Interaction Experiments (MCCI) project is conducting reactor material experiments and associated analysis to achieve the following objectives: (1) resolve the ex-vessel debris coolability issue through a program that focuses on providing both confirmatory evidence and test data for the coolability mechanisms identified in MACE integral effects tests, and (2) address remaining uncertainties related to long-term two-dimensional molten core-concrete interactions under both wet and dry cavity conditions. Achievement of these two program objectives will demonstrate the efficacy of severe accident management guidelines for existing plants, and provide the technical basis for better containment designs for future plants. In terms of satisfying these objectives, the Management Board (MB) approved the conduct of two long-term 2-D Core-Concrete Interaction (CCI) experiments designed to provide information in several areas, including: (i) lateral vs. axial power split during dry core-concrete interaction, (ii) integral debris coolability data following late phase flooding, and (iii) data regarding the nature and extent of the cooling transient following breach of the crust formed at the melt-water interface. The first of these two tests, CCI-1, was conducted on December 19, 2003. This test investigated the interaction of a fully oxidized 400 kg PWR core melt, initially containing 8 wt % calcined siliceous concrete, with a specially designed two-dimensional siliceous concrete test section with an initial cross-sectional area of 50 cm x 50 cm. The second of these two planned tests, CCI-2, will be conducted with a nearly identical test facility and experiment boundary conditions, but with a Limestone/Common Sand (LCS) concrete test section to investigate the effect of concrete type on the two-dimensional core-concrete interaction and debris cooling behavior. The objective of this report is to provide the overall test plan for CCI-2 to enable pretest calculations to be carried out. The report begins by providing a summary description of the CCI-2 test apparatus, followed by a description of the planned test operating procedure. Overall specifications for CCI-2 are provided in Table 1-1.

Farmer, M. T.; Kilsdonk, D. J.; Lomperski, S.; Aeschlimann, R. W.; Basu, S. (Nuclear Engineering Division)

2011-05-23T23:59:59.000Z

423

Characterization of 3d topological insulators by 2d invariants  

E-Print Network [OSTI]

The prediction of non-trivial topological phases in Bloch insulators in three dimensions has recently been experimentally verified. Here, I provide a picture for obtaining the $Z_{2}$ invariants for a three dimensional topological insulator by deforming suitable 2d planes in momentum space and by using a formula for the 2d $Z_{2}$ invariant based on the Chern number. The physical interpretation of this formula is also clarified through the connection between this formulation of the $Z_{2}$ invariant and the quantization of spin Hall conductance in two dimensions.

Rahul Roy

2010-04-20T23:59:59.000Z

424

Radiative heat transfer in 2D Dirac materials  

E-Print Network [OSTI]

We compute the radiative heat transfer between two sheets of 2D Dirac materials, including topological Chern insulators and graphene, within the framework of the local approximation for the optical response of these materials. In this approximation, which neglects spatial dispersion, we derive both numerically and analytically the short-distance asymptotic of the near-field heat transfer in these systems, and show that it scales as the inverse of the distance between the two sheets. Finally, we discuss the limitations to the validity of this scaling law imposed by spatial dispersion in 2D Dirac materials.

Pablo Rodriguez-Lopez; Wang-Kong Tse; Diego A. R. Dalvit

2015-02-02T23:59:59.000Z

425

Finite temperature analysis of a quasi2D dipolar gas  

E-Print Network [OSTI]

We present finite temperature analysis of a quasi2D dipolar gas. To do this, we use the Hartree Fock Bogoliubov method within the Popov approximation. This formalism is a set of non-local equations containing the dipole-dipole interaction and the condensate and thermal correlation functions, which are solved self-consistently. We detail the numerical method used to implement the scheme. We present density profiles for a finite temperature dipolar gas in quasi2D, and compare these results to a gas with zero-range interactions. Additionally, we analyze the excitation spectrum and study the impact of the thermal exchange.

Ticknor, Christopher

2012-01-01T23:59:59.000Z

426

Scattering due to Schottky barrier height spatial fluctuation on two dimensional electron gas in AlGaN/GaN high electron mobility transistors  

SciTech Connect (OSTI)

A scattering mechanism related to the Schottky barrier height (SBH) spatial fluctuation of the two dimensional electron gas (2DEG) in AlGaN/GaN heterostructures is presented. We find that the low field mobility is on the order of 10{sup 4}–10{sup 6} cm{sup 2}/Vs. The 2DEG transport properties are found to be influenced by both the mobility and 2DEG density variations caused by the SBH fluctuation. Our results indicate that a uniform Schottky contact is highly desired to minimize the influence of SBH inhomogeneity on the device performance.

Li, Huijie; Liu, Guipeng, E-mail: liugp@semi.ac.cn; Wei, Hongyuan; Jiao, Chunmei; Wang, Jianxia; Zhang, Heng; Dong Jin, Dong; Feng, Yuxia; Yang, Shaoyan, E-mail: sh-yyang@semi.ac.cn; Wang, Lianshan; Zhu, Qinsheng; Wang, Zhan-Guo [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China and Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)] [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China and Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)

2013-12-02T23:59:59.000Z

427

Anisotropic scattering effect of the inclined misfit dislocation on the two-dimensional electron gas in Al(In)GaN/GaN heterostructures  

SciTech Connect (OSTI)

In this paper, a theory is developed to study the anisotropic scattering effect of the inclined misfit dislocation on the two-dimensional electron gas in Al(In)GaN/GaN heterostructures. The inclined misfit dislocation, which differs from the well-known vertical threading dislocation, has a remarkable tilt angle from the vertical. The predicted electron mobility shows a remarkable anisotropy. It has a maximum mobility value along the direction perpendicular to the projection of the inclined dislocation line, and a minimum mobility value along the direction parallel to the projection. The degree of the anisotropic scattering effect will be even greater with the increase of the tilt angle.

Jin, Dong-Dong [Key Laboratory of Semiconductor Materials Science, and Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Department of Physics, Tsinghua University, Beijing 100084 (China); Wang, Lian-shan, E-mail: ls-wang@semi.ac.cn; Yang, Shao-Yan, E-mail: sh-yyang@semi.ac.cn; Li, Hui-jie; Zhang, Heng; Wang, Jian-xia; Xiang, Ruo-fei; Wei, Hong-yuan; Jiao, Chun-mei; Liu, Xiang-Lin; Zhu, Qin-Sheng, E-mail: qszhu@semi.ac.cn; Wang, Zhan-Guo [Key Laboratory of Semiconductor Materials Science, and Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Zhang, Liu-Wan [Department of Physics, Tsinghua University, Beijing 100084 (China)

2014-01-28T23:59:59.000Z

428

Large voltage modulation in magnetic field sensors from two-dimensional arrays of Y-Ba-Cu-O nano Josephson junctions  

SciTech Connect (OSTI)

We have fabricated and tested two-dimensional arrays of YBa{sub 2}Cu{sub 3}O{sub 7??} superconducting quantum interference devices. The arrays contain over 36?000 nano Josephson junctions fabricated from ion irradiation of YBa{sub 2}Cu{sub 3}O{sub 7??} through narrow slits in a resist-mask that was patterned with electron beam lithography and reactive ion etching. Measurements of current-biased arrays in magnetic field exhibit large voltage modulations as high as 30?mV.

Cybart, Shane A., E-mail: scybart@ucsd.edu; Dynes, R. C. [Department of Physics, University of California San Diego, La Jolla, California 92093 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Cho, E. Y.; Wong, T. J. [Department of Physics, University of California San Diego, La Jolla, California 92093 (United States); Glyantsev, V. N.; Huh, J. U.; Yung, C. S.; Moeckly, B. H. [Superconductor Technologies Inc., Santa Barbara, California 93111 (United States); Beeman, J. W.; Ulin-Avila, E.; Wu, S. M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2014-02-10T23:59:59.000Z

429

Finite temperature topological order in 2D topological color codes  

E-Print Network [OSTI]

In this work the topological order at finite temperature in two-dimensional color code is studied. The topological entropy is used to measure the behavior of the topological order. Topological order in color code arises from the colored string-net structures. By imposing the hard constrained limit the exact solution of the entanglement entropy becomes possible. For finite size systems, by raising the temperature, one type of string-net structure is thermalized and the associative topological entropy vanishes. In the thermodynamic limit the underlying topological order is fragile even at very low temperatures. Taking first the thermodynamic limit and then the zero-temperature limit and vice versa does not commute, and their difference is related only to the topology of regions. The contribution of the colors and symmetry of the model in the topological entropy is also discussed. It is shown how the gauge symmetry of the color code underlies the topological entropy.

Mehdi Kargarian

2009-07-19T23:59:59.000Z

430

Visual exploration of 2D autonomous dynamical systems  

E-Print Network [OSTI]

In an introductory course on dynamical systems or Hamiltonian mechanics, vector field diagrams are a central tool to show a system's qualitative behaviour in a certain domain. Because of their low sampling rates and the involved issues of vector normalization, these plots give only a coarse insight and are unable to convey the vector field behaviour at locations with high variation, in particular in the neighborhood of critical points. Similarly, automatic generation of phase portraits based on traditional sampling cannot precisely capture separatrices or limit cylces. In this paper, we present ASysViewer, an application for the interactive visual exploration of two-dimensional autonomous dynamical systems using line integral convolution techniques for visualization, and grid-based techniques to extract critical points and separatrices. ASysViewer is addressed to undergraduate students during their first course in dynamical systems or Hamiltonian mechanics.

Müller, Thomas

2015-01-01T23:59:59.000Z

431

Probabilistic methods applied to 2D electromagnetic numerical dosimetry  

E-Print Network [OSTI]

the number of realizations. When the modeling of the 3D interaction between the human body and a cellphoneProbabilistic methods applied to 2D electromagnetic numerical dosimetry D. Voyer F. Musy L. Nicolas dosimetry problems in order to take into account the variability of the input parameters. Methodology

Paris-Sud XI, Université de

432

2D Static Light Scattering for Dairy Based Applications  

E-Print Network [OSTI]

2D Static Light Scattering for Dairy Based Applications Jacob Lercke Skytte Kongens Lyngby 2014 Ph information on the microstructure. The second paper makes a direction comparison between the light scattering a recently introduced light scattering tech- nique. The system setup of the technique is highly flexible

433

Universal topological phase of 2D stabilizer codes  

E-Print Network [OSTI]

Two topological phases are equivalent if they are connected by a local unitary transformation. In this sense, classifying topological phases amounts to classifying long-range entanglement patterns. We show that all 2D topological stabilizer codes are equivalent to several copies of one universal phase: Kitaev's topological code. Error correction benefits from the corresponding local mappings.

H. Bombin; Guillaume Duclos-Cianci; David Poulin

2011-03-23T23:59:59.000Z

434

A Fokker-Planck-Landau collision equation solver on two-dimensional velocity grid and its application to particle-in-cell simulation  

SciTech Connect (OSTI)

An approximate two-dimensional solver of the nonlinear Fokker-Planck-Landau collision operator has been developed using the assumption that the particle probability distribution function is independent of gyroangle in the limit of strong magnetic field. The isotropic one-dimensional scheme developed for nonlinear Fokker-Planck-Landau equation by Buet and Cordier [J. Comput. Phys. 179, 43 (2002)] and for linear Fokker-Planck-Landau equation by Chang and Cooper [J. Comput. Phys. 6, 1 (1970)] have been modified and extended to two-dimensional nonlinear equation. In addition, a method is suggested to apply the new velocity-grid based collision solver to Lagrangian particle-in-cell simulation by adjusting the weights of marker particles and is applied to a five dimensional particle-in-cell code to calculate the neoclassical ion thermal conductivity in a tokamak plasma. Error verifications show practical aspects of the present scheme for both grid-based and particle-based kinetic codes.

Yoon, E. S.; Chang, C. S., E-mail: cschang@pppl.gov [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Korea Advanced Institute of Science and Technology, Yuseong-gu, DaeJeon 305-701 (Korea, Republic of)

2014-03-15T23:59:59.000Z

435

The Anglo-Australian Observatory's 2dF Facility  

E-Print Network [OSTI]

The 2dF (Two-degree Field) facility at the prime focus of the Anglo-Australian Telescope provides multiple object spectroscopy over a 2 degree field of view. Up to 400 target fibres can be independently positioned by a complex robot. Two spectrographs provide spectra with resolutions of between 500 and 2000, over wavelength ranges of 440nm and 110nm respectively. The 2dF facility began routine observations in 1997. 2dF was designed primarily for galaxy redshift surveys and has a number of innovative features. The large corrector lens incorporates an atmospheric dispersion compensator, essential for wide wavelength coverage with small diameter fibres. The instrument has two full sets of fibres on separate field plates, so that re-configuring can be done in parallel with observing. The robot positioner places one fibre every 6 seconds, to a precision of 0.3 arcsec (20micron) over the full field. All components of 2dF, including the spectrographs, are mounted on a 5-m diameter telescope top-end ring for ease of handling and to keep the optical fibres short in order to maximise UV throughput . There is a pipeline data reduction system which allows each data set to be fully analysed while the next field is being observed. In this paper we provide the historical background to the 2dF facility, the design philosophy, a full technical description and a summary of the performance of the instrument. We also briefly review its scientific applications and possible future developments.

I. J. Lewis; R. D. Cannon; K. Taylor; K. Glazebrook; J. A. Bailey; I. K. Baldry; J. R. Barton; T. J. Bridges; G. B. Dalton; T. J. Farrell; P. M. Gray; A. Lankshear; C. McCowage; I. R. Parry; R. M. Sharples; K. Shortridge; G. A. Smith; J. Stevenson; J. O. Straede; L. G. Waller; J. D. Whittard; J. K. Wilcox; K. C. Willis

2002-02-08T23:59:59.000Z

436

Application of 2D VSP Imaging Technology to the Targeting of Exploration and Production Wells in a Basin and Range Geothermal System  

Broader source: Energy.gov [DOE]

DOE Geothermal Peer Review 2010 - Presentation. Project objectives: A novel 2D VSP imaging technology and patented processing techniques will be used to create accurate, high-resolution reflection images of a classic Basin and Range fault system in a fraction of previous compute times.

437

Multichannel response analysis on 2D projection views for detection of clustered microcalcifications in digital breast tomosynthesis  

SciTech Connect (OSTI)

Purpose: To investigate the feasibility of a new two-dimensional (2D) multichannel response (MCR) analysis approach for the detection of clustered microcalcifications (MCs) in digital breast tomosynthesis (DBT). Methods: With IRB approval and informed consent, a data set of two-view DBTs from 42 breasts containing biopsy-proven MC clusters was collected in this study. The authors developed a 2D approach for MC detection using projection view (PV) images rather than the reconstructed three-dimensional (3D) DBT volume. Signal-to-noise ratio (SNR) enhancement processing was first applied to each PV to enhance the potential MCs. The locations of MC candidates were then identified with iterative thresholding. The individual MCs were decomposed with Hermite–Gaussian (HG) and Laguerre–Gaussian (LG) basis functions and the channelized Hotelling model was trained to produce the MCRs for each MC on the 2D images. The MCRs from the PVs were fused in 3D by a coincidence counting method that backprojects the MC candidates on the PVs and traces the coincidence of their ray paths in 3D. The 3D MCR was used to differentiate the true MCs from false positives (FPs). Finally a dynamic clustering method was used to identify the potential MC clusters in the DBT volume based on the fact that true MCs of clinical significance appear in clusters. Using two-fold cross validation, the performance of the 3D MCR for classification of true and false MCs was estimated by the area under the receiver operating characteristic (ROC) curve and the overall performance of the MCR approach for detection of clustered MCs was assessed by free response receiver operating characteristic (FROC) analysis. Results: When the HG basis function was used for MCR analysis, the detection of MC cluster achieved case-based test sensitivities of 80% and 90% at the average FP rates of 0.65 and 1.55 FPs per DBT volume, respectively. With LG basis function, the average FP rates were 0.62 and 1.57 per DBT volume at the same sensitivity levels. The difference in the two sets of basis functions for detection of MCs did not show statistical significance. Conclusions: The authors' experimental results indicate that the MCR approach is promising for the detection of MCs on PV images. The HG or LG basis functions are both effective in characterizing the signal response of MCs using the channelized Hotelling model. The coincidence counting method for fusion of the 2D MCR in 3D is an important step for FP reduction. Further study is underway to improve the MCR approach for microcalcification detection in DBT.

Wei, Jun, E-mail: jvwei@umich.edu; Chan, Heang-Ping; Hadjiiski, Lubomir M.; Helvie, Mark A.; Lu, Yao; Zhou, Chuan; Samala, Ravi [Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109-5842 (United States)] [Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109-5842 (United States)

2014-04-15T23:59:59.000Z

438

NON-INVASIVE DETERMINATION OF THE LOCATION AND DISTRBUTION OF FREE-PHASE DENSE NONAQUEOUS PHASE LIQUIDS (DNAPL) BY SEISMIC REFLECTION TECHNIQUES  

SciTech Connect (OSTI)

The Earth Sciences and Resources Institute, University of South Carolina is conducting a proof of concept study to determine the location and distribution of subsurface DNAPL carbon tetrachloride (CCl{sub 4}) contamination at the 216-Z-9 crib, 200 West area, DOE Hanford Site, Washington by use of two-dimensional high-resolution seismic reflection surveys and borehole geophysical data. The study makes use of recent advances in seismic reflection amplitude versus offset (AVO) technology to directly detect the presence of subsurface DNAPL. The techniques proposed are noninvasive means of site characterization and direct free-phase DNAPL detection. This final report covers the results of Tasks 1, 2, and 3. Task (1) contains site evaluation and seismic modeling studies. The site evaluation consists of identifying and collecting preexisting geological and geophysical information regarding subsurface structure and the presence and quantity of DNAPL. The seismic modeling studies were undertaken to determine the likelihood that an AVO response exists and its probable manifestation. Task (2) is the design and acquisition of 2-D seismic reflection data to image areas of probable high concentration of DNAPL. Task (3) is the processing and interpretation of the 2-D data. During the commission of these tasks four seismic reflection profiles were collected. Subsurface velocity information was obtained by vertical seismic profile surveys in three wells. The interpretation of these data is in two parts. Part one is the construction and interpretation of structural contour maps of the contact between the Hanford Fine unit and the underlying Plio/Pleistocene unit and of the contact between the Plio/Pleistocene unit and the underlying caliche layer. These two contacts were determined to be the most likely surfaces to contain the highest concentration CCl{sub 4}. Part two of the interpretation uses the results of the AVO modeling to locate any seismic amplitude anomalies that might be associated with the presence of high concentrations of CCl{sub 4}. Based on the modeling results three different methods of AVO analysis were preformed on the seismic data: enhanced amplitude stacks, offset range limited stacks, and gradient stacks. Seismic models indicate that the reflection from the contact between the Hanford Fine and the Plio/Pleistocene should exhibit amplitude variations where there are high concentrations of CCl{sub 4}. A series of different scenarios were modeled. The first scenario is the Hanford Fine pores are 100% saturated with CCl{sub 4} and the underlying Plio/Pleistocene pores are saturated with air. In this scenario the reflection coefficients are slightly negative at the small angles of incidence and become increasing more negative at the larger angles of incidence (dim-out). The second scenario is the Hanford Fine pores are saturated with air and Plio/Pleistocene pores are saturated with CCl{sub 4}. In this scenario the reflection coefficients are slightly positive at the small angles of incidence and become negative at the large angles of incidence (polarity reversal). Finally the third scenario is both the Hanford Fine and the Plio/Pleistocene pores are saturated CCl{sub 4}. In this scenario the reflection coefficients at the small angles of incidence are slightly positive, but much less than background response, and with increasing angle of incidence the reflection coefficients become slightly more positive. On the field data areas where extraction wells have high concentrations of CCl{sub 4} a corresponding dim-out and/or a polarity reversal is noted.

Michael G. Waddell; William J. Domoracki; Jerome Eyer

2003-01-01T23:59:59.000Z

439

Neutron reflecting supermirror structure  

DOE Patents [OSTI]

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources.

Wood, James L. (Drayton Plains, MI)

1992-01-01T23:59:59.000Z

440

Neutron reflecting supermirror structure  

DOE Patents [OSTI]

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. 2 figs.

Wood, J.L.

1992-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Anomalous Hall effect in a two-dimensional Dirac band: The link between the Kubo-Streda formula and the semiclassical Boltzmann equation approach RID B-5617-2009  

E-Print Network [OSTI]

calculations are carried out in a band-eigenstate representation. The equivalence we establish is verified by explicit calculations for the case of the two-dimensional Dirac model Hamiltonian relevant to graphene....

Sinitsyn, N. A.; MacDonald, A. H.; Jungwirth, T.; Dugaev, V. K.; Sinova, Jairo.

2007-01-01T23:59:59.000Z

442

Assessment of 2D resistivity structures using 1D inversions  

E-Print Network [OSTI]

) E. R. Hoskins (Head of Departsnent) May 1987 ABSTRACT Assessment of 2D Resistivity Structures Using 1D Inversion. (May 1987) Les Paul Beard, B. S. , East Texas State University Chairman of Advisory Committee: Dr. Frank Dale Morgan Resistivity... sections from Schlumberger soundings over and near normal fault. 4. 11 Inverted sections from Wenner soundings over and near nornral fault 4. 12 Schlumberger apparent resistivity contour for normal fault 4. 13 Wenner apparenl resistivity contour...

Beard, Les Paul

1987-01-01T23:59:59.000Z

443

Valley and electric photocurrents in 2D silicon and graphene  

SciTech Connect (OSTI)

We show that the optical excitation of multi-valley systems leads to valley currents which depend on the light polarization. The net electric current, determined by the vector sum of single-valley contributions, vanishes for some peculiar distributions of carriers in the valley and momentum spaces forming a pure valley current. We report on the study of this phenomenon, both experimental and theoretical, for graphene and 2D electron channels on the silicon surface.

Tarasenko, S. A.; Ivchenko, E. L. [Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); Olbrich, P.; Ganichev, S. D. [Terahertz Center, University of Regensburg, 93040 Regensburg (Germany)

2013-12-04T23:59:59.000Z

444

ARM - Evaluation Product - 2D Gridded Surface Data Set  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcal Documentation DataDatastreamswacrspeccmaskcopolDatastreamsxsacrslrAlaskaDefensiveProcesses EngineeringProducts2D

445

Double resonance Raman spectra of graphene : a full 2D calculation  

E-Print Network [OSTI]

Visible range Raman spectra of graphene are generated based on the double resonant process employing a full two-dimensional numerical calculation applying second-order perturbation theory. Tight binding expressions for ...

Narula, Rohit

2007-01-01T23:59:59.000Z

446

Coexistence of nearly free and strongly bound trions from magneto-photoluminescence of two-dimensional quantum structures with tunable electron or hole concentration  

SciTech Connect (OSTI)

We report on polarization-resolved photoluminescence studies of diverse excitonic complexes formed in GaAs quantum wells with a high-mobility two-dimensional hole gas in magnetic fields up to 23 T. Using two-beam illumination we decrease the hole concentration beyond the point of conversion from p- to n-type structures. We have demonstrated charge conversion between positive and negative exciton complexes (both free and bound to acceptors in the well). The switch between the electron and hole gases allowed us to distinguish between the emission lines from positive trions moving almost freely in the quantum well and bound to ionized acceptors in the barrier, which indicate their coexistence in the same well.

Jadczak, J.; Bryja, L.; Misiewicz, J.; Wójs, A. [Institute of Physics, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw (Poland); Potemski, M. [Grenoble High Magnetic Field Laboratory, CNRS, 38-042 Grenoble (France); Liu, F.; Yakovlev, D. R.; Bayer, M. [Experimentelle Physik 2, Technische Universität Dortmund, D-44227 Dortmund (Germany); Reuter, D.; Wieck, A. [Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätstraße (Germany); Nicoll, C. A.; Farrer, I.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE (United Kingdom)

2013-12-04T23:59:59.000Z

447

Screening of remote charge scattering sites from the oxide/silicon interface of strained Si two-dimensional electron gases by an intermediate tunable shielding electron layer  

SciTech Connect (OSTI)

We report the strong screening of the remote charge scattering sites from the oxide/semiconductor interface of buried enhancement-mode undoped Si two-dimensional electron gases (2DEGs), by introducing a tunable shielding electron layer between the 2DEG and the scattering sites. When a high density of electrons in the buried silicon quantum well exists, the tunneling of electrons from the buried layer to the surface quantum well can lead to the formation of a nearly immobile surface electron layer. The screening of the remote charges at the interface by this newly formed surface electron layer results in an increase in the mobility of the buried 2DEG. Furthermore, a significant decrease in the minimum mobile electron density of the 2DEG occurs as well. Together, these effects can reduce the increased detrimental effect of interface charges as the setback distance for the 2DEG to the surface is reduced for improved lateral confinement by top gates.

Huang, Chiao-Ti, E-mail: chiaoti@princeton.edu; Li, Jiun-Yun; Chou, Kevin S.; Sturm, James C. [Department of Electrical Engineering, Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544 (United States)

2014-06-16T23:59:59.000Z

448

Global parameter optimization of Mather type plasma focus in the framework of the Gratton-Vargas two-dimensional snowplow model  

E-Print Network [OSTI]

Dense Plasma Focus (DPF) is known to produce highly energetic ions, electrons and plasma environment which can be used for breeding of short-lived isotopes, plasma nanotechnology and other material processing applications. Commercial utilization of DPF in such areas would need a design tool which can be deployed in an automatic search for the best possible device configuration for a given application. The recently revisited [S K H Auluck, Physics of Plasmas 20, 112501 (2013)] Gratton-Vargas (GV) two-dimensional analytical snowplow model of plasma focus provides a numerical formula for dynamic inductance of a Mather type plasma focus fitted to thousands of automated computations, which enables construction of such design tool. This inductance formula is utilized in the present work to explore global optimization, based on first-principles optimality criteria, in a 4-dimensional parameter-subspace of the zero-resistance GV model. The optimization process is shown to reproduce the empirically observed constancy ...

Auluck, S K H

2014-01-01T23:59:59.000Z

449

Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry of coal liquids produced during a coal liquefaction process  

SciTech Connect (OSTI)

Comprehensive two-dimensional gas chromatography (GC) coupled to time-of-flight mass spectrometry (MS) has been applied to the analysis of coal-derived liquids from the former British Coal Point-of-Ayr coal liquefaction plant. The feed to the hydrocracker and the resulting product were analyzed. The results refer almost exclusively to the plant-derived recycle solvent, known as the liquefaction solvent; the molecular mass range of the GC does not exceed that of the solvent. The method allows for the resolution of the numerous structural isomers of tetralin and methyl indan, one pair of hydrogen-donor (necessary for the dissolution of coal) and isomeric nondonor (that reduce the hydrogen donors) components of the recycle solvent. In addition, the n-alkanes that concentrate in the recycle solvent are easily observed in comparison with the results from one-dimensional GC-MS. 24 refs., 6 figs., 1 tab.

Jacqui F. Hamilton; Alistair. C. Lewis; Marcos Millan; Keith D. Bartle; Alan A. Herod; Rafael Kandiyoti [University of York, York (United Kingdom). Department of Chemistry

2007-01-15T23:59:59.000Z

450

Very Large Scale Integration of Nano-Patterned YBa2Cu3O7-delta Josephson Junctions in a Two-Dimensional Array  

SciTech Connect (OSTI)

Very large scale integration of Josephson junctions in a two-dimensional series-parallel array has been achieved by ion irradiating a YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} film through slits in a nano-fabricated mask created with electron beam lithography and reactive ion etching. The mask consisted of 15,820 high-aspect ratio (20:1), 35-nm wide slits that restricted the irradiation in the film below to form Josephson junctions. Characterizing each parallel segment k, containing 28 junctions, with a single critical current I{sub ck} we found a standard deviation in I{sub ck} of about 16%.

Cybart, Shane A; Anton, Steven; Wu, Stephen; Clarke, John; Dynes, Robert

2009-09-01T23:59:59.000Z

451

ESSDERC, Bucharest, Sep. 19, 2013.Kaustav Banerjee, UCSB 2D Electronics: Graphene and Beyond  

E-Print Network [OSTI]

ESSDERC, Bucharest, Sep. 19, 2013.Kaustav Banerjee, UCSB 2D Electronics: Graphene and Beyond Electronics? I will use 2D electronic materials: Graphene and Beyond #12;ESSDERC, Bucharest, Sep. 19, 2013.Kaustav Banerjee, UCSB 2D Electronic Materials 2D family tree TMD family Graphene family Other families

Liebling, Michael

452

EPR study of the onset of long-range order in the 2D organo-metallic magnet Cu(pyz)2(pyo)2(PF6)2  

SciTech Connect (OSTI)

The spin (S) 1/2 two-dimensional (2D) square-lattice quantum Heisenberg antiferromagnet system has long been interesting to theoretical physicists due to the variety of transitions that can arise. Moreover, the role of S = 1/2 fluctuations on a square lattice in the mechanism for cuprate superconductivity is hotly debated. Low dimensional metal-organic magnets, such as Cu(pyz){sub 2}(pyo){sub 2}(PF{sub 6}){sub 2}, offer the possibility to readily control the exchange parameters in a 20 system by changing chemical composition, thus creating spin architectures with desirable properties 'to order'. For a perfectly 20 system, long range magnetic order would not occur at finite temperature. However, in the metal-organic systems, interlayer coupling gives rise to a finite Neel temperature. For these quasi-2D systems the ordering temperature is dominated by the weakest (the interlayer) exchange interaction, whereas the saturation magnetic field is dominated by the strongest exchange interactions, thus providing a means of estimating the spatial exchange anisotropy in the system. It should be noted that the more 2D the system, the wider the temperature (T) range, T{sub N} < T < J/k{sub B}, over which magnetic fluctuations dominate. As evident by the ratio of magnetic saturation field, H{sub sat} {approx} 30 T, to the Neel temperature, T{sub N} = 1.72 K, Cu(pyz){sub 2}(pyo){sub 2}(PF{sub 6}){sub 2} is a good example of a 2D system with the anisotropy between inplane and interplane exchange interactions being of the order of 10{sup 3}.

Mcdonald, Ross D [Los Alamos National Laboratory; Ayala - Valenzuela, Oscar E [Los Alamos National Laboratory; Singleton, John [Los Alamos National Laboratory; Goddard, Paul A [OXFORD; Franke, I [OXFORD; Manson, J. L. [EWU

2011-01-14T23:59:59.000Z

453

Two-dimensional river modeling  

E-Print Network [OSTI]

Recommendations 57 REFERENCES VITA 59 63 LIST OF FIGURES page Figure 1. Coordinate system for three-dimensional flow. 13 Figure 2. Illustration of depth-averaged velocity. Figure 3. Flow in a simple channel, finite element network and typical cross... strongly curved channel hend, velocity field. 34 Figure 8. Flow in a strongly curved channel bend, velocity contours. Figure 9. Flow in a meandering creek, three- dimensional ground surface. 35 37 Figure 10. Flow in a meandering creek, finite element...

Thompson, James Cameron

1988-01-01T23:59:59.000Z

454

Tandem resonator reflectance modulator  

DOE Patents [OSTI]

A wide band optical modulator is grown on a substrate as tandem Fabry-Perot resonators including three mirrors spaced by two cavities. The absorption of one cavity is changed relative to the absorption of the other cavity by an applied electric field, to cause a change in total reflected light, as light reflecting from the outer mirrors is in phase and light reflecting from the inner mirror is out of phase with light from the outer mirrors. 8 figs.

Fritz, I.J.; Wendt, J.R.

1994-09-06T23:59:59.000Z

455

Neutron reflecting supermirror structure  

DOE Patents [OSTI]

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. One layer of each set of bilayers consist of titanium, and the second layer of each set of bilayers consist of an alloy of nickel with carbon interstitially present in the nickel alloy.

Wood, James L. (Drayton Plains, MI)

1992-01-01T23:59:59.000Z

456

Multiple Ising Spins Coupled to 2d Quantum Gravity  

E-Print Network [OSTI]

We study a model in which p independent Ising spins are coupled to 2d quantum gravity (in the form of dynamical planar phi-cubed graphs). Consideration is given to the p tends to infinity limit in which the partition function becomes dominated by certain graphs; we identify most of these graphs. A truncated model is solved exactly providing information about the behaviour of the full model in the limit of small beta. Finally, we derive a bound for the critical value of the coupling constant, beta_c and examine the magnetization transition in the limit p tends to zero.

M. G. Harris; J. F. Wheater

1994-04-28T23:59:59.000Z

457

Black liquor gasification phase 2D final report  

SciTech Connect (OSTI)

This report covers work conducted by Rockwell International under Amendment 5 to Subcontract STR/DOE-12 of Cooperative Agreement DE-AC-05-80CS40341 between St. Regis Corporation (now Champion International) and the Department of Energy (DOE). The work has been designated Phase 2D of the overall program to differentiate it from prior work under the same subcontract. The overall program is aimed at demonstrating the feasibility of and providing design data for the Rockwell process for gasifying Kraft black liquor. In this process, concentrated black liquor is converted into low-Btu fuel gas and reduced melt by reaction with air in a specially designed gasification reactor.

Kohl, A.L.; Stewart, A.E.

1988-06-01T23:59:59.000Z

458

MHL 2D Wind/Wave | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth's Heat JumpIncMAKGalway Bay IEOWCCatcher.pngWavemill < MHKYOGbioWaveMHL 2D

459

Quantum oscillations and subband properties of the two-dimensional electron gas at the LaAlO{sub 3}/SrTiO{sub 3} interface  

SciTech Connect (OSTI)

We have performed high field magnetotransport measurements to investigate the interface electron gas in a high mobility SrTiO{sub 3}/SrCuO{sub 2}/LaAlO{sub 3}/SrTiO{sub 3} heterostructure. Shubnikov-de Haas oscillations reveal several 2D conduction subbands with carrier effective masses of 0.9m{sub e} and 2m{sub e}, quantum mobilities of order 2000 cm{sup 2}/V s, and band edges only a few millielectronvolts below the Fermi energy. Measurements in tilted magnetic fields confirm the 2D character of the electron gas, and show evidence of inter-subband scattering.

McCollam, A., E-mail: A.McCollam@science.ru.nl; Guduru, V. K.; Zeitler, U.; Maan, J. C. [High Field Magnet Laboratory and Institute for Molecules and Materials, Radboud University Nijmegen, 6525 ED Nijmegen (Netherlands); Wenderich, S.; Kruize, M. K.; Molegraaf, H. J. A.; Huijben, M.; Koster, G.; Blank, D. H. A.; Rijnders, G.; Brinkman, A.; Hilgenkamp, H. [Faculty of Science and Technology and MESA Institute for Nanotechnology, University of Twente, 7500 AE Enschede (Netherlands)

2014-02-01T23:59:59.000Z

460

OECD MCCI project long-term 2-D molten core concrete interaction test design report, Rev. 0. September 30, 2002.  

SciTech Connect (OSTI)

The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core-concrete interaction when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. As a follow-on program to MACE, The Melt Coolability and Concrete Interaction Experiments (MCCI) project is conducting reactor material experiments and associated analysis to achieve the following two technical objectives: (1) resolve the ex-vessel debris coolability issue through a program that focuses on providing both confirmatory evidence and test data for the coolability mechanisms identified in MACE integral effects tests, and (2) address remaining uncertainties related to long-term two-dimensional molten core-concrete interactions under both wet and dry cavity conditions. Achievement of these two objectives will demonstrate the efficacy of severe accident management guidelines for existing plants, and provide the technical basis for better containment designs for future plants. In terms of the first program objective, the Small-Scale Water Ingression and Crust Strength (SSWICS) test series has been initiated to provide fundamental information on the ability of water to ingress into cracks and fissures that form in the debris during quench, thereby augmenting the otherwise conduction-limited heat transfer process. A test plan for Melt Eruption Separate Effects Tests (MESET) has also been developed to provide information on the extent of crust growth and melt eruptions as a function of gas sparging rate under well-controlled experiment conditions. In terms of the second program objective, the project Management Board (MB) has approved startup activities required to carry out experiments to address remaining uncertainties related to long-term two-dimensional molten core-concrete interaction. In particular, for both wet and dry cavity conditions, there is uncertainty insofar as evaluating the lateral vs. axial power split during a core-concrete interaction due to a lack of experiment data. As a result, there are differences in the 2-D cavity erosion predicted by codes such as MELCOR, WECHSL, and COSACO. The first step towards generating this data is to produce a test plan for review by the Project Review Group (PRG). The purpose of this document is to provide this plan.

Farmer, M. T.; Kilsdonk, D. J.; Lomperski, S.; Aeschliman, R. W.; Basu, S. (Nuclear Engineering Division); (NRC)

2011-05-23T23:59:59.000Z

Note: This page contains sample records for the topic "two-dimensional 2d reflection" from the National Library of EnergyBeta (NLEBeta).
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461

Laser patterning and preferential orientation of two-dimensional planar {beta}-BaB{sub 2}O{sub 4} crystals on the glass surface  

SciTech Connect (OSTI)

The laser-induced crystallization method is applied to pattern two-dimensional planar {beta}-BaB{sub 2}O{sub 4} crystals on the surface of Sm{sub 2}O{sub 3}-BaO-B{sub 2}O{sub 3} glass. By scanning Yb:YVO{sub 4} fiber lasers (wavelength: 1080 nm) continuously with a small step (0.5 {mu}m) between laser irradiated areas, homogeneous planar {beta}-BaB{sub 2}O{sub 4} crystals are patterned successfully, and a preferential growth orientation of {beta}-BaB{sub 2}O{sub 4} crystals is confirmed from linearly polarized micro-Raman scattering spectrum and second harmonic intensity measurements. It is found that the crystal growth direction is perpendicular to the laser scanning direction. This relation, i.e., the perpendicular relation, is different from the behavior in discrete crystal line patterning, where the crystal growth direction is consistent with the laser scanning direction. The present study proposes the possibility of the control of crystal growth direction in laser-induced crystallization in glasses. - Graphical abstract: This figure shows confocal scanning laser microscope and polarized optical microscope photographs for {beta}-BaB{sub 2}O{sub 4} crystals obtained by laser irradiations. The laser scanning was repeated with a step of 0.5 {mu}m between the lines using the condition of the power of P=0.8 W and a laser scanning speed of S=8 {mu}m/s. It is suggested that {beta}-BaB{sub 2}O{sub 4} crystals in the overlapped laser-irradiated region are highly oriented and the c-axis direction of {beta}-BaB{sub 2}O{sub 4} crystals is perpendicular to the laser scanning direction. Highlights: Black-Right-Pointing-Pointer Laser-induced crystallization method is applied to pattern {beta}-BaB{sub 2}O{sub 4} crystals. Black-Right-Pointing-Pointer Two-dimensional planar crystals are patterned on the glass surface. Black-Right-Pointing-Pointer Preferential growth orientation of {beta}-BaB{sub 2}O{sub 4} crystals is confirmed. Black-Right-Pointing-Pointer Crystal growth direction is perpendicular to the laser scanning direction.

Suzuki, F.; Ogawa, K.; Honma, T. [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan); Komatsu, T., E-mail: komatsu@mst.nagaokaut.ac.jp [Department of Materials Science and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka-cho, Nagaoka 940-2188 (Japan)

2012-01-15T23:59:59.000Z

462

Vacuum compatible, high-speed, 2-D mirror tilt stage  

DOE Patents [OSTI]

A compact and vacuum compatible magnetic-coil driven tiltable stage that is equipped with a high efficiency reflective coating can be employed as a scanner in EUV applications. The drive electronics for the scanner is fully in situ programmable and rapidly switchable.

Denham; Paul E. (Crockett, CA)

2007-09-25T23:59:59.000Z

463

Madelung Fluid Model for The Most Likely Wave Function of a Single Free Particle in Two Dimensional Space with a Given Average Energy  

E-Print Network [OSTI]

We consider spatially two dimensional Madelung fluid whose irrotational motion reduces into the Schr\\"odinger equation for a single free particle. In this respect, we regard the former as a direct generalization of the latter, allowing a rotational quantum flow. We then ask for the most likely wave function possessing a given average energy by maximizing the Shannon information entropy over the quantum probability density. We show that there exists a class of solutions in which the wave function is self-trapped, rotationally symmetric, spatially localized with finite support, and spinning around its center, yet stationary. The stationarity comes from the balance between the attractive quantum force field of a trapping quantum potential generated by quantum probability density and the repulsive centrifugal force of a rotating velocity vector field. We further show that there is a limiting case where the wave function is non-spinning and yet still stationary. This special state turns out to be the lowest stationary state of the ordinary Schr\\"odinger equation for a particle in a cylindrical tube classical potential.

Agung Budiyono; Ken Umeno

2009-02-23T23:59:59.000Z

464

The effect of velocity boundary conditions on the heat transfer and flow topology in two-dimensional Rayleigh-B\\'enard convection  

E-Print Network [OSTI]

The effect of various velocity boundary condition is studied in two-dimensional Rayleigh-B\\'enard convection. Combinations of no-slip, stress-free and periodic boundary conditions are used on both the sidewalls and the horizontal plates. For the studied Rayleigh numbers Ra between $10^8$ and $10^{11}$ the heat transport is lower for $\\Gamma = 0.33$ than for $\\Gamma = 1$ in case of no-slip sidewalls. This is surprisingly opposite for stress-free sidewalls, where the heat transport increases for lower aspect-ratio. In wider cells the aspect-ratio dependence is observed to disappear for $\\text{Ra} \\ge 10^{10}$. Two distinct flow types with very different dynamics can be seen, mostly dependent on the plate velocity boundary condition, namely roll-like flow and horizontal zonal flow, which have a substantial effect on the dynamics and heat transport in the system. The predominantly horizontal zonal flow suppresses heat flux and is observed for stress-free and asymmetric plates. Low aspect-ratio periodic sidewall s...

van der Poel, Erwin P; Verzicco, Roberto; Lohse, Detlef

2015-01-01T23:59:59.000Z

465

Extracting the spectral function of the cuprates by a full two-dimensional analysis: Angle-resolved photoemission spectra of Bi2Sr2CuO6  

SciTech Connect (OSTI)

Recently, angle-resolved photoemission spectroscopy (ARPES) has revealed a dispersion anomaly at high binding energy near 0.3-0.5 eV in various families of the high-temperature superconductors. For further studies of this anomaly we present a new two-dimensional fitting-scheme and apply it to high-statistics ARPES data of the strongly-overdoped Bi{sub 2}Sr{sub 2}CuO{sub 6} cuprate superconductor. The procedure allows us to extract the self-energy in an extended energy and momentum range. It is found that the spectral function of Bi{sub 2}Sr{sub 2}CuO{sub 6} can be parameterized using a small set of tight-binding parameters and a weakly-momentum-dependent self-energy up to 0.7 eV in binding energy and over the entire first Brillouin zone. Moreover the analysis gives an estimate of the momentum dependence of the matrix element, a quantity, which is often neglected in ARPES analyses.

Meevasana, W.

2010-04-30T23:59:59.000Z

466

Characterization of heavy masses of two-dimensional conduction subband in InGaAs/InAlAs MQW structures by pulsed cyclotron resonance technology  

SciTech Connect (OSTI)

Conduction-band effective masses in a direction parallel to the quantum well plane were investigated in n-type-modulation-doped InGaAs/InAlAs multiquantum well system. Thicknesses of well and barrier were 5 and 10 nm. Three highly-doped specimens having about 1 {times} 10{sup 12} cm{sup {minus}2} per one quantum well were prepared by MBE. Double-crystal X-ray diffraction was used to check the crystal quality. Heavy electron effective masses, almost 50% bigger than the band edge mass of 0.041m{sub 0}, were measured by far-infrared and infrared cyclotron resonances under pulse high magnetic fields up to 100 T. Nonparabolicity of this subband was less than 12% by comparing the two cyclotron resonances. Observed two-dimensional subband structure was quite different from conduction-band effective mass in a direction perpendicular to the same quantum well and from GaAs/GaAlAs quantum well system.

Kotera, N.; Tanaka, K. [Kyushu Inst. of Technology, Iizuka, Fukuoka (Japan); Arimoto, H.; Miura, N. [Univ. of Tokyo, Roppongi, Tokyo (Japan). Inst. of Solid State Physics; Jones, E.D. [Sandia National Labs., Albuquerque, NM (United States); Mishima, T. [Hitachi Ltd., Kokubunji, Tokyo (Japan). Central Research Lab.; Washima, M. [Hitachi Cable, Ltd., Tsukuba, Ibaraki (Japan). Advanced Research Center

1998-05-01T23:59:59.000Z

467

HEXAGONAL ARRAY STRUCTURE FOR 2D NDE APPLICATIONS  

SciTech Connect (OSTI)

This paper describes a combination of simulation and experimentation to evaluate the advantages offered by utilizing a hexagonal shaped array element in a 2D NDE array structure. The active material is a 1-3 connectivity piezoelectric composite structure incorporating triangular shaped pillars--each hexagonal array element comprising six triangular pillars. A combination of PZFlex, COMSOL and Matlab has been used to simulate the behavior of this device microstructure, for operation around 2.25 MHz, with unimodal behavior and low levels of mechanical cross-coupling predicted. Furthermore, the application of hexagonal array elements enables the array aperture to increase by approximately 30%, compared to a conventional orthogonal array matrix and hence will provide enhanced volumetric coverage and SNR. Prototype array configurations demonstrate good corroboration of the theoretically predicted mechanical cross-coupling between adjacent array elements (approx23 dB).

Dziewierz, J.; Ramadas, S. N.; Gachagan, A.; O'Leary, R. L. [Centre for Ultrasonic Engineering, Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, G1 1XW (United Kingdom)

2010-02-22T23:59:59.000Z

468

Exhibit 2D -Refund of Royalties UT-B Contracts Div Page 1 of 1  

E-Print Network [OSTI]

Exhibit 2D - Refund of Royalties UT-B Contracts Div Dec 2005 Page 1 of 1 ex2D-dec05.doc Exhibit 2D Ref: DEAR 970.5227-8 REFUND OF ROYALTIES (Dec 2005) (a) During performance of