National Library of Energy BETA

Sample records for two-dimensional seismic surveying

  1. Seismic isolation of two dimensional periodic foundations

    SciTech Connect (OSTI)

    Yan, Y.; Mo, Y. L.; Laskar, A.; Cheng, Z.; Shi, Z.; Menq, F.; Tang, Y.

    2014-07-28

    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.

  2. Joint two-dimensional DC resistivity and seismic travel time inversion with cross-gradients constraints

    E-Print Network [OSTI]

    Meju, Max

    Joint two-dimensional DC resistivity and seismic travel time inversion with cross to evaluate the structural features common to both methods. The cross-gradients function is incorporated method. The resultant iterative two-dimensional (2-D) joint inversion scheme is successfully applied

  3. Leasing and Exploration * Seismic geophysical surveys

    E-Print Network [OSTI]

    #12;Leasing and Exploration * Seismic geophysical surveys * Exploratory drilling using various of these incremental steps; leasing and exploration. Subsequent phases of OCS development (production, transportation) prepared by MMS, as well as pertinent research on the bowhead whale and matters related to oil exploration

  4. Geodetic Survey At Central Nevada Seismic Zone Region (Blewitt...

    Open Energy Info (EERE)

    Geodetic Survey At Central Nevada Seismic Zone Region (Blewitt, Et Al., 2003) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Geodetic Survey At...

  5. Geodetic Survey At Central Nevada Seismic Zone Region (Blewitt...

    Open Energy Info (EERE)

    Geodetic Survey At Central Nevada Seismic Zone Region (Blewitt Et Al, 2005) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Geodetic Survey At...

  6. Refraction Survey At Central Nevada Seismic Zone Region (Heimgartner...

    Open Energy Info (EERE)

    Refraction Survey At Central Nevada Seismic Zone Region (Heimgartner, Et Al., 2005) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Refraction...

  7. Direct-Current Resistivity Survey At Central Nevada Seismic Zone...

    Open Energy Info (EERE)

    Direct-Current Resistivity Survey At Central Nevada Seismic Zone Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity:...

  8. Investigation of Seismic Surveys and Enhancement of Seismic Images 

    E-Print Network [OSTI]

    Bilgi, Celal

    2015-06-05

    The ability to recover a seismic image of subsurface structure from recorded seismic data plays an important role in exploration of seismology applications. Processing techniques are applied to recover the geology from data recorded in the field...

  9. An active seismic reconnaissance survey of the Mount Princeton...

    Open Energy Info (EERE)

    An active seismic reconnaissance survey of the Mount Princeton area, Chaffee County, Colorado Jump to: navigation, search OpenEI Reference LibraryAdd to library Thesis: An active...

  10. Two-dimensional river modeling 

    E-Print Network [OSTI]

    Thompson, James Cameron

    1988-01-01

    heavily vegetated flood plain. It is found that the two-dimensional model can determine the flow more completely and more accurately than a corresponding one- dimensional model. Two-dimensional models are best applied where the flow conditions... committee, W. P. James, R. A. Wurbs, and R. 0. Reid, for their support and interest in this research. Dr. James, in particular, has shown great foresight in supporting broader use of two-dimensional river modeling. Dave Froehlich deserves much...

  11. A 3D-3C Reflection Seismic Survey and Data Integration to Identify...

    Open Energy Info (EERE)

    A 3D-3C Reflection Seismic Survey and Data Integration to Identify the Seismic Response of Fractures and Permeable Zones Over a Known Geothermal Resource at Soda Lake, Churchill...

  12. Image resolution analysis: a new, robust approach to seismic survey design 

    E-Print Network [OSTI]

    Tzimeas, Constantinos

    2005-08-29

    Seismic survey design methods often rely on qualitative measures to provide an optimal image of their objective target. Fold, ray tracing techniques counting ray hits on binned interfaces, and even advanced 3-D survey ...

  13. Electrical Resistivity and Seismic Surveys at the Nevada Test Site, Nevada, April 2007

    SciTech Connect (OSTI)

    Seth S. Haines; Bethany L. Burton; Donald S. Sweetkind; Theodore H. Asch

    2009-03-30

    In April 2007, the USGS collected direct-current (DC) electrical resistivity data and shear- (S) and compressional- (P) wave seismic data to provide new detail of previously mapped, overlapping fault splays at two administrative areas in the Nevada Test Site (NTS). In NTS Area 7, we collected two-dimensional DC resistivity data along a transect crossing the Yucca Fault parallel to, and between, two transects along which resistivity data were collected in a previous study in 2006. In addition, we collected three-dimensional DC resistivity data in a grid that overlies part of the 2007 transect. The DC resistivity data show that the fault has a footwall that is more conductive than the hanging wall and an along-strike progression of the fault in a location where overlapping splays are present. Co-located with the northernmost of the two 2006 DC resistivity transects, we acquired S- and P-wave seismic data for both reflection and refraction processing. The S-wave data are corrupted by large amounts of converted (P-wave) energy likely due to the abundance of fractured caliche in the shallow subsurface. The P-wave data show minimal reflected energy, but they show clear refracted first arrivals. We have inverted these first arrival times to determine P-wave seismic velocity models. The seismic model for the transect in Area 7 shows low velocities extending to the base of the model at the location of the Yucca Fault, as well as low velocities at the eastern end of the transect, in the vicinity of the adjacent crater. These new surveys provide further detail about the geometry of the Yucca Fault in this location where it shows two overlapping splays. We collected P- and S-wave seismic data along a transect in the southern part of NTS Area 2, corresponding with the location of a 2006 DC resistivity transect that targeted a set of small faults identified with field mapping. Again, the S-wave data are difficult to interpret. The P-wave data show clear first arrivals that we inverted, yielding a velocity model that shows lateral heterogeneity similar to the 2006 DC resistivity models. Finally, we collected P-wave data along a second transect in Area 2, located north of the first line and in an area of a very minor fault that was targeted by another 2006 DC resistivity survey. The P-wave refraction velocity model shows generally high velocities, with a zone of somewhat lower velocities in the central part of the transect. The position of the low velocity zone corresponds with the location of a minor fault, though it is unclear whether the two are related. Together, these results demonstrate the value of geophysical data for mapping the subsurface extent of faults. The 2007 DC resistivity data complement the 2006 data and provide important new detail of the overlapping fault splays. The seismic data demonstrate the ability of P-wave refraction methods to identify the damage zones at faults, and they show the difficulties associated with S-wave methods in areas with caliche. Combining all of the geophysical data from the Area 7 studies, we are able to develop a coherent interpretation of the relation between the site geology, the fault, and the observations.

  14. Two dimensional unstable scar statistics.

    SciTech Connect (OSTI)

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Kotulski, Joseph Daniel; Lee, Kelvin S. H. (ITT Industries/AES Los Angeles, CA)

    2006-12-01

    This report examines the localization of time harmonic high frequency modal fields in two dimensional cavities along periodic paths between opposing sides of the cavity. The cases where these orbits lead to unstable localized modes are known as scars. This paper examines the enhancements for these unstable orbits when the opposing mirrors are both convex and concave. In the latter case the construction includes the treatment of interior foci.

  15. Coupling: Impact and Implications for High-Resolution Time-Lapse Seismic Surveying

    E-Print Network [OSTI]

    Walters, Shelby Lynn

    2008-07-28

    the first downhole shot, indicating an improved ground to surface seal. Reflection amplitudes decrease significantly after the first downhole shot, indicating a decrease in source coupling of body wave energy. Reflection amplitude remained approximately... be used to successfully monitor enhanced oil recovery processes, and by the mid-1990s time-lapse seismic surveying evolved into a promising technology for oil production management (He et al., 1996; Janson, 2001). Though time-lapse seismic techniques...

  16. University of Alberta A TRACKING SYSTEM FOR A SEISMIC SURVEYING MOBILE ROBOT

    E-Print Network [OSTI]

    Smith, James Andrew

    University of Alberta A TRACKING SYSTEM FOR A SEISMIC SURVEYING MOBILE ROBOT by James Andrew Smith, Alberta Spring 2001 #12;University of Alberta Faculty of Graduate Studies and Research The undersigned://www.sce.carleton.ca/faculty/chinneck/thesis.html The University of Alberta Thesis Document Style for LATEX by Fahiem Bacchus et alii The Emacs text editor

  17. An archaeological survey along a seismic line in Village Creek State Park Hardin County, Texas 

    E-Print Network [OSTI]

    Moore, William

    2015-06-03

    An Archaeological Survey was conducted along 6600 feet of seismic line with a right-of-way of ten feet for TGS Onshore Geophysical Company by Brazos Valley Research Associates on November 7, 1991. The area examined is located in Village creek State...

  18. Two-dimensional materials for electronic applications

    E-Print Network [OSTI]

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

    2013-01-01

    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 ...

  19. Pen Branch fault program: Consolidated report on the seismic reflection surveys and the shallow drilling

    SciTech Connect (OSTI)

    Stieve, A.L.; Stephenson, D.E.; Aadland, R.K.

    1991-03-23

    The Pen Branch fault was identified in the subsurface at the Savannah River Site (SRS) in 1989 based upon interpretation of earlier seismic reflection surveys and other geologic investigations (Seismorgraph Services Incorp., 1973; Chapman and DiStefano, 1989; Snipes, Fallaw and Price, 1989). A program was initiated at that time to determine the capability of the fault to release seismic energy (Price and others, 1989) as defined in the Nuclear Regulatory Commission regulatory guidelines, 10 CFR 100 Appendix A. This report presents the results of the Pen Branch fault investigation based on data acquired from seismic reflection surveys and shallow drilling across the fault completed at this time. The Earth Science Advisory Committee (ESAC) has reviewed the results of these investigations and unanimously agrees with the conclusion of Westinghouse Savannah River Company (WSRC) that the Pen Branch fault is a non-capable fault. ESAC is a committee of 12 earth science professionals from academia and industry with the charter of providing outside peer review of SRS geotechnical, seismic, and ground water modeling programs.

  20. An Archaeological Survey of High Probability Areas within Geokinetics, USA, Inc.'s Perry Ranch 3-D Seismic Survey in Brazoria and Matagorda Counties, Texas: Volume 1: The Terrestrial Survey 

    E-Print Network [OSTI]

    Moore, William

    2015-07-30

    An archaeological survey of the Geokinetics USA, Inc.’s Perry Ranch 3-D seismic survey was conducted by Brazos Valley Research Associates (BVRA) in conjunction with Dixie Environmental Services Company (DESCO), LP from ...

  1. Cosmologies with Two-Dimensional Inhomogeneity

    E-Print Network [OSTI]

    A. Feinstein; J. Ibįńez; Ruth Lazkoz

    1995-11-27

    We present a new generating algorithm to construct exact non static solutions of the Einstein field equations with two-dimensional inhomogeneity. Infinite dimensional families of $G_1$ inhomogeneous solutions with a self interacting scalar field, or alternatively with perfect fluid, can be constructed using this algorithm. Some families of solutions and the applications of the algorithm are discussed.

  2. Universal entanglement entropy in two-dimensional conformal quantum...

    Office of Scientific and Technical Information (OSTI)

    two-dimensional conformal quantum critical systems, i.e., systems with scale-invariant wave functions. They include two-dimensional generalized quantum dimer models on bipartite...

  3. Statistical Mechanics of Two-dimensional Foams

    E-Print Network [OSTI]

    Marc Durand

    2010-09-07

    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.

  4. Fully localized two-dimensional embedded solitons

    SciTech Connect (OSTI)

    Yang Jianke [Department of Mathematics and Statistics, University of Vermont, Burlington, Vermont 05401 (United States)

    2010-11-15

    We report the prediction of fully localized two-dimensional embedded solitons. These solitons are obtained in a quasi-one-dimensional waveguide array which is periodic along one spatial direction and localized along the orthogonal direction. Under appropriate nonlinearity, these solitons are found to exist inside the Bloch bands (continuous spectrum) of the waveguide and thus are embedded solitons. These embedded solitons are fully localized along both spatial directions. In addition, they are fully stable under perturbations.

  5. Stability of Two-Dimensional Soft Quasicrystals

    E-Print Network [OSTI]

    Kai Jiang; Jiajun Tong; Pingwen Zhang; An-Chang Shi

    2015-05-26

    The relative stability of two-dimensional soft quasicrystals is examined using a recently developed projection method which provides a unified numerical framework to compute the free energy of periodic crystal and quasicrystals. Accurate free energies of numerous ordered phases, including dodecagonal, decagonal and octagonal quasicrystals, are obtained for a simple model, i.e. the Lifshitz-Petrich free energy functional, of soft quasicrystals with two length-scales. The availability of the free energy allows us to construct phase diagrams of the system, demonstrating that, for the Lifshitz-Petrich model, the dodecagonal and decagonal quasicrystals can become stable phases, whereas the octagonal quasicrystal stays as a metastable phase.

  6. Flow transitions in two-dimensional foams

    E-Print Network [OSTI]

    Christopher Gilbreth; Scott Sullivan; Michael Dennin

    2006-08-08

    For sufficiently slow rates of strain, flowing foam can exhibit inhomogeneous flows. The nature of these flows is an area of active study in both two-dimensional model foams and three dimensional foam. Recent work in three-dimensional foam has identified three distinct regimes of flow [S. Rodts, J. C. Baudez, and P. Coussot, Europhys. Lett. {\\bf 69}, 636 (2005)]. Two of these regimes are identified with continuum behavior (full flow and shear-banding), and the third regime is identified as a discrete regime exhibiting extreme localization. In this paper, the discrete regime is studied in more detail using a model two dimensional foam: a bubble raft. We characterize the behavior of the bubble raft subjected to a constant rate of strain as a function of time, system size, and applied rate of strain. We observe localized flow that is consistent with the coexistence of a power-law fluid with rigid body rotation. As a function of applied rate of strain, there is a transition from a continuum description of the flow to discrete flow when the thickness of the flow region is approximately 10 bubbles. This occurs at an applied rotation rate of approximately $0.07 {\\rm s^{-1}}$.

  7. Two dimensional Sen connections in general relativity

    E-Print Network [OSTI]

    L. B. Szabados

    1994-02-01

    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.

  8. Two-dimensional fourier transform spectrometer

    DOE Patents [OSTI]

    DeFlores, Lauren; Tokmakoff, Andrei

    2013-09-03

    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.

  9. Couette Flow of Two-Dimensional Foams

    E-Print Network [OSTI]

    G. Katgert; B. P. Tighe; M. E. Möbius; M. van Hecke

    2010-04-26

    We experimentally investigate flow of quasi two-dimensional disordered foams in Couette geometries, both for foams squeezed below a top plate and for freely floating foams. With the top-plate, the flows are strongly localized and rate dependent. For the freely floating foams the flow profiles become essentially rate-independent, the local and global rheology do not match, and in particular the foam flows in regions where the stress is below the global yield stress. We attribute this to nonlocal effects and show that the "fluidity" model recently introduced by Goyon {\\em et al.} ({\\em Nature}, {\\bf 454} (2008)) captures the essential features of flow both with and without a top plate.

  10. Sieving hydrogen isotopes through two dimensional crystals

    E-Print Network [OSTI]

    M. Lozada-Hidalgo; S. Hu; O. Marshall; A. Mishchenko; A. N. Grigorenko; R. A. W. Dryfe; B. Radha; I. V. Grigorieva; A. K. Geim

    2015-11-20

    One-atom-thick crystals are impermeable to atoms and molecules, but hydrogen ions (thermal protons) penetrate through them. We show that monolayers of graphene and boron nitride can be used to separate hydrogen ion isotopes. Employing electrical measurements and mass spectrometry, we find that deuterons permeate through these crystals much slower than protons, resulting in a separation factor of 10 at room temperature. The isotope effect is attributed to a difference of about 60 meV between zero-point energies of incident protons and deuterons, which translates into the equivalent difference in the activation barriers posed by two dimensional crystals. In addition to providing insight into the proton transport mechanism, the demonstrated approach offers a competitive and scalable way for hydrogen isotope enrichment.

  11. Renormalization of two-dimensional XQCD

    E-Print Network [OSTI]

    Hidenori Fukaya; Ryo Yamamura

    2015-10-15

    Recently, Kaplan proposed an interesting extension of QCD named Extended QCD or XQCD with bosonic auxiliary fields [1]. While its partition function is kept exactly the same as that of QCD, XQCD naturally contains properties of low-energy hadrons. We apply this extension to the two-dimensional QCD in the large $N_c$ limit ('t Hooft model) [2]. In this solvable model, it is possible to directly examine the hadronic picture of the 2d XQCD and analyze its renormalization group flow to understand how the auxiliary degrees of freedom behave in the low energy region. We confirm that the additional scalar fields can become dynamical acquiring the kinetic term, and its parity-odd part becomes dominant in the low energy region. This renomalization of XQCD provides an "extension" of the renormalization scheme of QCD, inserting different field variables from those in the original theory, without any changes in physical observables.

  12. Sieving hydrogen isotopes through two dimensional crystals

    E-Print Network [OSTI]

    Lozada-Hidalgo, M; Marshall, O; Mishchenko, A; Grigorenko, A N; Dryfe, R A W; Radha, B; Grigorieva, I V; Geim, A K

    2015-01-01

    One-atom-thick crystals are impermeable to atoms and molecules, but hydrogen ions (thermal protons) penetrate through them. We show that monolayers of graphene and boron nitride can be used to separate hydrogen ion isotopes. Employing electrical measurements and mass spectrometry, we find that deuterons permeate through these crystals much slower than protons, resulting in a separation factor of 10 at room temperature. The isotope effect is attributed to a difference of about 60 meV between zero-point energies of incident protons and deuterons, which translates into the equivalent difference in the activation barriers posed by two dimensional crystals. In addition to providing insight into the proton transport mechanism, the demonstrated approach offers a competitive and scalable way for hydrogen isotope enrichment.

  13. Internal tide generation by arbitrary two-dimensional topography

    E-Print Network [OSTI]

    Peacock, Thomas

    To date, analytical models of internal tide generation by two-dimensional ridges have considered only idealized shapes. Here, we advance the Green function approach to address the generation of internal tides by two-dimensional ...

  14. 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...

  15. Using Two-Dimensional Colloidal Crystals to Understand Crystallography

    E-Print Network [OSTI]

    Loening, Niko

    Using Two-Dimensional Colloidal Crystals to Understand Crystallography Instructor Notes Geometric). #12;Using Two-Dimensional Colloidal Crystals to Understand Crystallography Instructions for Students the patterns that result from the diffraction of electromagnetic radiation by a crystal provides structural

  16. High resolution, shallow seismic reflection survey of the Pen Branch fault

    SciTech Connect (OSTI)

    Stieve, A.

    1991-05-15

    The purpose of this project, at the Savannah River River Site (SRS) was to acquire, process, and interpret 28 km (17.4 miles) of high resolution seismic reflection data taken across the trace of the Pen Branch fault and other suspected, intersecting north-south trending faults. The survey was optimized for the upper 300 ft of geologic strata in order to demonstrate the existence of very shallow, flat lying horizons, and to determine the depth of the fault or to sediments deformed by the fault. Field acquisition and processing parameters were selected to define small scale spatial variability and structural features in the vicinity of the Pen Branch fault leading to the definition and the location of the Pen Branch fault, the shallowest extent of the fault, and the quantification of the sense and magnitude of motion. Associated geophysical, borehole, and geologic data were incorporated into the investigation to assist in the determination of optimal parameters and aid in the interpretation.

  17. Turbulent equipartitions in two dimensional drift convection

    SciTech Connect (OSTI)

    Isichenko, M.B.; Yankov, V.V.

    1995-07-25

    Unlike the thermodynamic equipartition of energy in conservative systems, turbulent equipartitions (TEP) describe strongly non-equilibrium systems such as turbulent plasmas. In turbulent systems, energy is no longer a good invariant, but one can utilize the conservation of other quantities, such as adiabatic invariants, frozen-in magnetic flux, entropy, or combination thereof, in order to derive new, turbulent quasi-equilibria. These TEP equilibria assume various forms, but in general they sustain spatially inhomogeneous distributions of the usual thermodynamic quantities such as density or temperature. This mechanism explains the effects of particle and energy pinch in tokamaks. The analysis of the relaxed states caused by turbulent mixing is based on the existence of Lagrangian invariants (quantities constant along fluid-particle or other orbits). A turbulent equipartition corresponds to the spatially uniform distribution of relevant Lagrangian invariants. The existence of such turbulent equilibria is demonstrated in the simple model of two dimensional electrostatically turbulent plasma in an inhomogeneous magnetic field. The turbulence is prescribed, and the turbulent transport is assumed to be much stronger than the classical collisional transport. The simplicity of the model makes it possible to derive the equations describing the relaxation to the TEP state in several limits.

  18. Dynamics of two-dimensional dipole systems

    SciTech Connect (OSTI)

    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)

    2010-09-15

    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.

  19. Two-Dimensional Self-Assembly in Diblock Copolymers

    E-Print Network [OSTI]

    Hosoi, A.E.

    2005-06-20

    Diblock copolymers confined to a two-dimensional surface may produce uniform features of macromolecular dimensions (10 ā?? 100 nm). We present a mathematical model for nanoscale pattern

  20. Two-dimensional simulation of the Raft River geothermal reservoir...

    Open Energy Info (EERE)

    and the time dependent temperature response of the wells at the Raft River, Idaho, Geothermal Resource were developed. A horizontal, two-dimensional, finite-difference model...

  1. Plastic flow in two-dimensional solids Akira Onuki

    E-Print Network [OSTI]

    Plastic flow in two-dimensional solids Akira Onuki Department of Physics, Kyoto University, Kyoto-Landau model of plastic deformation in two-dimensional solids is presented. The fundamental dynamic variables in uniaxial stretching. High-density dislocations produced in plastic flow do not disappear even if the flow

  2. Handling Database Updates in Two-dimensional Temporal Logic

    E-Print Network [OSTI]

    Finger, Marcelo

    Handling Database Updates in Two-dimensional Temporal Logic Marcelo Finger y Department (Draft version 0.2) Abstract This paper deals with the description of the evolution of the understanding in database systems due to updates. For this purpose, we introduce a two-dimensional temporal logic

  3. Electronic transport in two-dimensional graphene S. Das Sarma

    E-Print Network [OSTI]

    Rossi, Enrico

    . Monolayer graphene 409 2. Bilayer graphene 411 3. 2D Semiconductor structures 412 C. Elementary electronicElectronic transport in two-dimensional graphene S. Das Sarma Condensed Matter Theory Center; published 16 May 2011) A broad review of fundamental electronic properties of two-dimensional graphene

  4. Sensor Networking Using Two-Dimensional Electromagnetic Wave Yasutoshi Makino*

    E-Print Network [OSTI]

    Shinoda, Hiroyuki

    causes wastes of energy and interferences of communication. Since intense elec- tromagnetic waveSensor Networking Using Two-Dimensional Electromagnetic Wave Yasutoshi Makino* , Kouta Minamizawa* , and Hiroyuki Shinoda* In this paper, we propose a new technology for sensor networks named "Two Dimensional

  5. Alternative structures for two-dimensional MEMS optical switches [Invited

    E-Print Network [OSTI]

    Wai, Ping-kong Alexander

    Two-dimensional (2-D) microelectromechanical system (MEMS) optical switches have the merits of easy technologies have been proposed for building OXCs. Microelectromechanical system (MEMS) optical switches haveAlternative structures for two-dimensional MEMS optical switches [Invited] Victor O. K. Li

  6. Exploring two-dimensional electron gases with two-dimensional Fourier transform spectroscopy

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

    Paul, J.; Dey, P.; Tokumoto, T.; Reno, J. L.; Hilton, D. J.; Karaiskaj, D.

    2014-10-07

    The dephasing of excitons in a modulation doped single quantum well was carefully measured using time integrated four-wave mixing (FWM) and two-dimensional Fourier transform (2DFT) spectroscopy. These are the first 2DFT measurements performed on a modulation doped single quantum well. The inhomogeneous and homogeneous excitonic line widths were obtained from the diagonal and cross-diagonal profiles of the 2DFT spectra. The laser excitation density and temperature were varied and 2DFT spectra were collected. A very rapid increase of the dephasing decay, and as a result, an increase in the cross-diagonal 2DFT linewidths with temperature was observed. The lineshapes of the 2DFTmore »spectra suggest the presence of excitation induced dephasing and excitation induced shift.« less

  7. Healing of defects in a two-dimensional granular crystal

    E-Print Network [OSTI]

    Rice, Marie C

    2014-01-01

    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 ...

  8. Optical properties of two-dimensional transition metal dichalcogenides

    E-Print Network [OSTI]

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

    2014-01-01

    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 ...

  9. Chiral Jacobians and two-dimensional QED at finite temperature

    SciTech Connect (OSTI)

    Reuter, M.; Dittrich, W.

    1985-07-15

    We show that in massless two-dimensional QED there is no restoration of gauge symmetry at finite temperature (because the boson mass is temperature independent), using zeta-function techniques to solve the fermionic determinant exactly.

  10. Design and analysis of a two-dimensional camera array

    E-Print Network [OSTI]

    Yang, Jason C. (Jason Chieh-Sheng), 1977-

    2005-01-01

    I present the design and analysis of a two-dimensional camera array for virtual studio applications. It is possible to substitute conventional cameras and motion control devices with a real-time, light field camera array. ...

  11. Transformation optics scheme for two-dimensional materials

    E-Print Network [OSTI]

    Kumar, Anshuman

    Two-dimensional optical materials, such as graphene, can be characterized by surface conductivity. So far, the transformation optics schemes have focused on three-dimensional properties such as permittivity ? and permeability ...

  12. Anomalous Hall effect in a two-dimensional electron gas 

    E-Print Network [OSTI]

    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.

    2007-01-01

    The anomalous Hall effect in a magnetic two-dimensional electron gas with Rashba spin-orbit coupling is studied within the Kubo-Streda formalism in the presence of pointlike potential impurities. We find that all contributions ...

  13. Notes on the two-dimensional fractional Brownian motion

    E-Print Network [OSTI]

    Baudoin, Fabrice; Nualart, David

    2006-02-17

    We study the two-dimensional fractional Brownian motion with Hurst parameter H>½. In particular, we show, using stochastic calculus, that this process admits a skew-product decomposition and deduce from this representation some asymptotic properties...

  14. M-Theory and Two-Dimensional Effective Dynamics

    E-Print Network [OSTI]

    N. D. Lambert; P. C. West

    1999-08-09

    We calculate from M-theory the two-dimensional low energy effective dynamics of various brane configurations. In the first part we study configurations that have a dual description in type IIA string theory as two-dimensional (4,0) Yang-Mills theories with gauge group SU(N_1)xSU(N_2) and chiral fermions in the bi-fundamental representation. In the second part we derive related equations of motion which describe the low energy internal dynamics of a supersymmetric black hole in four-dimensional N=1 supergravity, obtained as an M-fivebrane wrapped on a complex four-cycle.

  15. A two-dimensional nematic phase of magnetic nanorods

    E-Print Network [OSTI]

    Kostyantyn Slyusarenko; Doru Constantin; Patrick Davidson

    2015-04-04

    We report a hybrid mesophase consisting of magnetic nanorods confined between the non-ionic surfactant bilayers of a lamellar phase. The magnetic field-induced ordering of the nanorods was measured experimentally and modeled by a two-dimensional Onsager theory including the third virial coefficient. The nanorods are strongly confined in layers, with no orientational coupling from one layer to the next. At high volume concentration they exhibit spontaneous in-plane orientational ordering and form a stack of independent two-dimensional nematic systems. This isotropic-nematic transition is first-order.

  16. Two-dimensional optimization of free electron laser designs

    DOE Patents [OSTI]

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

    1985-01-01

    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.

  17. Two-dimensional optimization of free-electron-laser designs

    DOE Patents [OSTI]

    Prosnitz, D.; Haas, R.A.

    1982-05-04

    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.

  18. Quasi-two Dimensional Hydrodynamics and Interaction of Vortex Tubes

    E-Print Network [OSTI]

    Zakharov, Vladimir

    Quasi-two Dimensional Hydrodynamics and Interaction of Vortex Tubes Vladimir Zakharov 1 but a careful study of the dynamics of the vortex tubes or their systems in a real 3-dimentional nonstationary for description of this type of flow looks very timely. Another motivation is the vortex dynamics

  19. Nonlinear Optical Processes in Two-Dimensional Semiconductor Structures 

    E-Print Network [OSTI]

    Wang, Yongrui

    2015-07-28

    The optical properties of two types of two-dimensional (2D) semiconductor structures are studied. One of them is for structures based on quantum wells (QWs), and the other is graphene. We study the dynamics of optically excited electron-hole plasma...

  20. Plasmonics with Two-Dimensional Conductors Hosang Yoon1

    E-Print Network [OSTI]

    Ham, Donhee

    in GaAs/AlGaAs two-dimensional (2D) electron gas (2DEG) and graphene, where electrons are perfectly, such as semiconductor heterojunction and graphene, contrast the surface plasmonic waves on bulk metals, as the former. Furthermore, the 2D plasmons can achieve much greater subwavelength confinement [5-7] with their velocity

  1. condmat/9801215 Crossovers in the Two Dimensional Ising Spin Glass

    E-Print Network [OSTI]

    Roma "La Sapienza", Universitą di

    cond­mat/9801215 v2 26 Jan 1998 Crossovers in the Two Dimensional Ising Spin Glass of extensive computer simulations we analyze in detail the two dimen­ sional \\SigmaJ Ising spin glass with ferromagnetic next­nearest­neighbor interactions. We found a crossover from ferromagnetic to ``spin glass'' like

  2. : A TWO-DIMENSIONAL BATHYMETRY BASED UNSTRUCTURED TRIANGULAR GRID GENERATOR

    E-Print Network [OSTI]

    unstructured triangular grid refinement algorithms, including the recent "off-centers" method, is providedBATTRI* : A TWO-DIMENSIONAL BATHYMETRY BASED UNSTRUCTURED TRIANGULAR GRID GENERATOR FOR FINITE utilities to check and improve grid quality. The final output mesh node locations, node depths and element

  3. Numerical Study of Two-Dimensional Viscous, Chemically Reacting Flow

    E-Print Network [OSTI]

    Texas at Arlington, University of

    A computational fluid dynamics code for two-dimensional, multi-species, laminar Navier- Stokes equations is developed to simulate a pulsed detonation based propulsion system and to analyze its performance. The stiffness due to coupling the fluid dynamics and the chem- ical kinetics is properly taken care of by using

  4. Dynamical confinement in bosonized two-dimensional QCD

    SciTech Connect (OSTI)

    Ferrando, A. ); Vento, V. )

    1994-03-15

    In the bosonized version of two-dimensional theories nontrivial boundary conditions (topology) play a crucial role. They are inevitable if one wants to describe nonsinglet states. In Abelian bosonization, color is the charge of a topological current in terms of a nonlinear meson field. We show that confinement appears as the dynamical collapse of the topology associated with its nontrivial boundary conditions.

  5. Methods and apparatus of suppressing tube waves within a bore hole and seismic surveying systems incorporating same

    DOE Patents [OSTI]

    West, Phillip B.; Haefner, Daryl

    2004-08-17

    Methods and apparatus for attenuating waves in a bore hole, and seismic surveying systems incorporating the same. In one embodiment, an attenuating device includes a soft compliant bladder coupled to a pressurized gas source. A pressure regulating system reduces the pressure of the gas from the gas source prior to entering the bladder and operates in conjunction with the hydrostatic pressure of the fluid in a bore hole to maintain the pressure of the bladder at a specified pressure relative to the surrounding bore hole pressure. Once the hydrostatic pressure of the bore hole fluid exceeds that of the gas source, bore hole fluid may be admitted into a vessel of the gas source to further compress and displace the gas contained therein. In another embodiment, a water-reactive material may be used to provide gas to the bladder wherein the amount of gas generated by the water-reactive material may depend on the hydrostatic pressure of the bore hole fluid.

  6. Methods and apparatus of suppressing tube waves within a bore hole and seismic surveying systems incorporating same

    DOE Patents [OSTI]

    West, Phillip B.; Haefner, Daryl

    2005-12-13

    Methods and apparatus for attenuating waves in a bore hole, and seismic surveying systems incorporating the same. In one embodiment, an attenuating device includes a soft compliant bladder coupled to a pressurized gas source. A pressure regulating system reduces the pressure of the gas from the gas source prior to entering the bladder and operates in conjunction with the hydrostatic pressure of the fluid in a bore hole to maintain the pressure of the bladder at a specified pressure relative to the surrounding bore hole pressure. Once the hydrostatic pressure of the bore hole fluid exceeds that of the gas source, bore hole fluid may be admitted into a vessel of the gas source to further compress and displace the gas contained therein. In another embodiment, a water-reactive material may be used to provide gas to the bladder wherein the amount of gas generated by the water-reactive material may depend on the hydrostatic pressure of the bore hole fluid.

  7. A 3D-3C Reflection Seismic Survey and Data Integration to Identify the

    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 Home Page on QA:QA J-E-1 SECTION JEnvironmental Jump to:EAand Dalton JumpProgram | Open EnergyEnergyEnergyEnergySeismic Response of

  8. A 3D-3C Reflection Seismic Survey and Data Integration to Identify the

    Broader source: Energy.gov (indexed) [DOE]

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergyTher i n c i p a l De p u t y A s s iof1 of 8 2Seismic Response of Fractures and

  9. Transport behavior of water molecules through two-dimensional nanopores

    SciTech Connect (OSTI)

    Zhu, Chongqin; Li, Hui; Meng, Sheng

    2014-11-14

    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.

  10. Point Defect Dynamics in Two-Dimensional Colloidal Crystals

    E-Print Network [OSTI]

    A. Libal; C. Reichhardt; C. J. Olson Reichhardt

    2006-12-16

    We study the topological configurations and dynamics of individual point defect vacancies and interstitials in a two-dimensional colloidal crystal. Our Brownian dynamics simulations show that the diffusion mechanism for vacancy defects occurs in two phases. The defect can glide along the crystal lattice directions, and it can rotate during an excited topological transition configuration to assume a different direction for the next period of gliding. The results for the vacancy defects are in good agreement with recent experiments. For the interstitial point defects, which were not studied in the experiments, we find several of the same modes of motion as in the vacancy defect case along with two additional diffusion pathways. The interstitial defects are more mobile than the vacancy defects due to the more two-dimensional nature of the diffusion of the interstitial defects.

  11. Quantum Hamilton-Jacobi Approach to Two Dimensional Singular Oscillator

    E-Print Network [OSTI]

    Ozlem Yesiltas; Bengu Demircioglu

    2008-04-27

    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.

  12. The Study of Two-dimensional Polytropic Stars

    E-Print Network [OSTI]

    Sanchari De; Somenath Chakrabarty

    2015-10-09

    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.

  13. Harmonic lattice behavior of two-dimensional colloidal crystals

    E-Print Network [OSTI]

    P. Keim; G. Maret; U. Herz; H. H. von Grünberg

    2004-02-17

    Using positional data from video-microscopy and applying the equipartition theorem for harmonic Hamiltonians, we determine the wave-vector-dependent normal mode spring constants of a two-dimensional colloidal model crystal and compare the measured band-structure to predictions of the harmonic lattice theory. We find good agreement for both the transversal and the longitudinal mode. For $q\\to 0$, the measured spring constants are consistent with the elastic moduli of the crystal.

  14. Accelerating universe in two-dimensional noncommutative dilaton cosmology

    E-Print Network [OSTI]

    Wontae Kim; Myung Seok Yoon

    2006-12-01

    We show that the phase transition from the decelerating universe to the accelerating universe, which is of relevance to the cosmological coincidence problem, is possible in the semiclassically quantized two-dimensional dilaton gravity by taking into account the noncommutative field variables during the finite time. Initially, the quantum-mechanically induced energy from the noncommutativity among the fields makes the early universe decelerate and subsequently the universe is accelerating because the dilaton driven cosmology becomes dominant later.

  15. Procedures for two-dimensional electrophoresis of proteins

    SciTech Connect (OSTI)

    Tollaksen, S.L.; Giometti, C.S.

    1996-10-01

    High-resolution two-dimensional gel electrophoresis (2DE) of proteins, using isoelectric focusing in the first dimension and sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) in the second, was first described in 1975. In the 20 years since those publications, numerous modifications of the original method have evolved. The ISO-DALT system of 2DE is a high-throughput approach that has stood the test of time. The problem of casting many isoelectric focusing gels and SDS-PAGE slab gels (up to 20) in a reproducible manner has been solved by the use of the techniques and equipment described in this manual. The ISO-DALT system of two-dimensional gel electrophoresis originated in the late 1970s and has been modified many times to improve its high-resolution, high-throughput capabilities. This report provides the detailed procedures used with the current ISO-DALT system to prepare, run, stain, and photograph two-dimensional gels for protein analysis.

  16. Ab initio simulations of two-dimensional electronic spectra: The SOS//QM/MM approach

    E-Print Network [OSTI]

    Rivalta, I; Nenov, A; Cerullo, G; Mukamel, S; Garavelli, M; Garavelli, M

    2013-01-01

    calculations. Conclusions Two-dimensional electronic spectroscopy holds great potential for studying structure, dynamics,

  17. Method for inverting reflection trace data from 3-D and 4-D seismic surveys and identifying subsurface fluid and pathways in and among hydrocarbon reservoirs based on impedance models

    DOE Patents [OSTI]

    He, W.; Anderson, R.N.

    1998-08-25

    A method is disclosed for inverting 3-D seismic reflection data obtained from seismic surveys to derive impedance models for a subsurface region, and for inversion of multiple 3-D seismic surveys (i.e., 4-D seismic surveys) of the same subsurface volume, separated in time to allow for dynamic fluid migration, such that small scale structure and regions of fluid and dynamic fluid flow within the subsurface volume being studied can be identified. The method allows for the mapping and quantification of available hydrocarbons within a reservoir and is thus useful for hydrocarbon prospecting and reservoir management. An iterative seismic inversion scheme constrained by actual well log data which uses a time/depth dependent seismic source function is employed to derive impedance models from 3-D and 4-D seismic datasets. The impedance values can be region grown to better isolate the low impedance hydrocarbon bearing regions. Impedance data derived from multiple 3-D seismic surveys of the same volume can be compared to identify regions of dynamic evolution and bypassed pay. Effective Oil Saturation or net oil thickness can also be derived from the impedance data and used for quantitative assessment of prospective drilling targets and reservoir management. 20 figs.

  18. Method for inverting reflection trace data from 3-D and 4-D seismic surveys and identifying subsurface fluid and pathways in and among hydrocarbon reservoirs based on impedance models

    DOE Patents [OSTI]

    He, Wei (New Milford, NJ); Anderson, Roger N. (New York, NY)

    1998-01-01

    A method is disclosed for inverting 3-D seismic reflection data obtained from seismic surveys to derive impedance models for a subsurface region, and for inversion of multiple 3-D seismic surveys (i.e., 4-D seismic surveys) of the same subsurface volume, separated in time to allow for dynamic fluid migration, such that small scale structure and regions of fluid and dynamic fluid flow within the subsurface volume being studied can be identified. The method allows for the mapping and quantification of available hydrocarbons within a reservoir and is thus useful for hydrocarbon prospecting and reservoir management. An iterative seismic inversion scheme constrained by actual well log data which uses a time/depth dependent seismic source function is employed to derive impedance models from 3-D and 4-D seismic datasets. The impedance values can be region grown to better isolate the low impedance hydrocarbon bearing regions. Impedance data derived from multiple 3-D seismic surveys of the same volume can be compared to identify regions of dynamic evolution and bypassed pay. Effective Oil Saturation or net oil thickness can also be derived from the impedance data and used for quantitative assessment of prospective drilling targets and reservoir management.

  19. Laminar flame and acoustic waves in two-dimensional flow

    SciTech Connect (OSTI)

    Zaytsev, M. L., E-mail: mlzaytsev@gmail.com; Akkerman, V. B., E-mail: slava.akkerman@gmail.com [Russian Academy of Sciences, Nuclear Safety Institute (Russian Federation)

    2011-03-15

    The complete system of fluid dynamics equations describing the development of instability of a reaction front in a two-dimensional flow in reversed time are reduced to a closed system of equations of front dynamics by using Lagrangian variables and integrals of motion. The system can be used to analyze processes behind the front without solving the complete system of fluid dynamics and chemical kinetics equations. It is demonstrated how the gas density disturbances induced by the moving front can be described in the adiabatic approximation.

  20. Rapid heating and cooling in two-dimensional Yukawa systems

    E-Print Network [OSTI]

    Yan Feng; Bin Liu; J. Goree

    2011-04-19

    Simulations are reported to investigate solid superheating and liquid supercooling of two-dimensional (2D) systems with a Yukawa interparticle potential. Motivated by experiments where a dusty plasma is heated and then cooled suddenly, we track particle motion using a simulation with Langevin dynamics. Hysteresis is observed when the temperature is varied rapidly in a heating and cooling cycle. As in the experiment, transient solid superheating, but not liquid supercooling, is observed. Solid superheating, which is characterized by solid structure above the melting point, is found to be promoted by a higher rate of temperature increase.

  1. Electronic transport in two-dimensional high dielectric constant nanosystems

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

    Ortuńo, M.; Somoza, A. M.; Vinokur, V. M.; Baturina, T. I.

    2015-04-10

    There has been remarkable recent progress in engineering high-dielectric constant two dimensional (2D) materials, which are being actively pursued for applications in nanoelectronics in capacitor and memory devices, energy storage, and high-frequency modulation in communication devices. Yet many of the unique properties of these systems are poorly understood and remain unexplored. Here we report a numerical study of hopping conductivity of the lateral network of capacitors, which models two-dimensional insulators, and demonstrate that 2D long-range Coulomb interactions lead to peculiar size effects. We find that the characteristic energy governing electronic transport scales logarithmically with either system size or electrostatic screeningmore »length depending on which one is shorter. Our results are relevant well beyond their immediate context, explaining, for example, recent experimental observations of logarithmic size dependence of electric conductivity of thin superconducting films in the critical vicinity of superconductor-insulator transition where a giant dielectric constant develops. Our findings mark a radical departure from the orthodox view of conductivity in 2D systems as a local characteristic of materials and establish its macroscopic global character as a generic property of high-dielectric constant 2D nanomaterials.« less

  2. Phonons in two-dimensional soft colloidal crystals

    E-Print Network [OSTI]

    Ke Chen; Tim Still; Samuel Schoenholz; Kevin B. Aptowicz; Michael Schindler; A. C. Maggs; Andrea J. Liu; A. G. Yodh

    2013-09-11

    The vibrational modes of pristine and polycrystalline monolayer colloidal crystals composed of thermosensitive microgel particles are measured using video microscopy and covariance matrix analysis. At low frequencies, the Debye relation for two dimensional harmonic crystals is observed in both crystal types; at higher frequencies, evidence for van Hove singularities in the phonon density of states is significantly smeared out by experimental noise and measurement statistics. The effects of these errors are analyzed using numerical simulations. We introduce methods to correct for these limitations, which can be applied to disordered systems as well as crystalline ones, and we show that application of the error correction procedure to the experimental data leads to more pronounced van Hove singularities in the pristine crystal. Finally, quasi-localized low-frequency modes in polycrystalline two-dimensional colloidal crystals are identified and demonstrated to correlate with structural defects such as dislocations, suggesting that quasi-localized low-frequency phonon modes may be used to identify local regions vulnerable to rearrangements in crystalline as well as amorphous solids.

  3. Alaska Maximum Number of Active Crews Engaged in Two-Dimensional Seismic

    Gasoline and Diesel Fuel Update (EIA)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustments (Billion Cubic Feet) Wyoming963 1.969 1.979Coal Consumers4.32 4.46ProductionCrude

  4. Alaska Maximum Number of Active Crews Engaged in Two-Dimensional Seismic

    Gasoline and Diesel Fuel Update (EIA)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustments (Billion Cubic Feet)Decade Year-0ProvedDecade2,948 2,724 2,570 2,304 1,670Same0New2009 2010

  5. 2D Seismic Reflection Data across Central Illinois

    SciTech Connect (OSTI)

    Smith, Valerie; Leetaru, Hannes

    2014-09-30

    In a continuing collaboration with the Midwest Geologic Sequestration Consortium (MGSC) on the Evaluation of the Carbon Sequestration Potential of the Cambro-Ordovician Strata of the Illinois and Michigan Basins project, Schlumberger Carbon Services and WesternGeco acquired two-dimensional (2D) seismic data in the Illinois Basin. This work included the design, acquisition and processing of approximately 125 miles of (2D) seismic reflection surveys running west to east in the central Illinois Basin. Schlumberger Carbon Services and WesternGeco oversaw the management of the field operations (including a pre-shoot planning, mobilization, acquisition and de-mobilization of the field personnel and equipment), procurement of the necessary permits to conduct the survey, post-shoot closure, processing of the raw data, and provided expert consultation as needed in the interpretation of the delivered product. Three 2D seismic lines were acquired across central Illinois during November and December 2010 and January 2011. Traversing the Illinois Basin, this 2D seismic survey was designed to image the stratigraphy of the Cambro-Ordovician sections and also to discern the basement topography. Prior to this survey, there were no regionally extensive 2D seismic data spanning this section of the Illinois Basin. Between the NW side of Morgan County and northwestern border of Douglas County, these seismic lines ran through very rural portions of the state. Starting in Morgan County, Line 101 was the longest at 93 miles in length and ended NE of Decatur, Illinois. Line 501 ran W-E from the Illinois Basin – Decatur Project (IBDP) site to northwestern Douglas County and was 25 miles in length. Line 601 was the shortest and ran N-S past the IBDP site and connected lines 101 and 501. All three lines are correlated to well logs at the IBDP site. Originally processed in 2011, the 2D seismic profiles exhibited a degradation of signal quality below ~400 millisecond (ms) which made interpretation of the Mt. Simon and Knox sections difficult. The data quality also gradually decreased moving westward across the state. To meet evolving project objectives, in 2012 the seismic data was re-processed using different techniques to enhance the signal quality thereby rendering a more coherent seismic profile for interpreters. It is believed that the seismic degradation could be caused by shallow natural gas deposits and Quaternary sediments (which include abandoned river and stream channels, former ponds, and swamps with peat deposits) that may have complicated or changed the seismic wavelet. Where previously limited by seismic coverage, the seismic profiles have provided valuable subsurface information across central Illinois. Some of the interpretations based on this survey included, but are not limited to: - Stratigraphy generally gently dips to the east from Morgan to Douglas County. - The Knox Supergroup roughly maintains its thickness. There is little evidence for faulting in the Knox. However, at least one resolvable fault penetrates the entire Knox section. - The Eau Claire Formation, the primary seal for the Mt. Simon Sandstone, appears to be continuous across the entire seismic profile. - The Mt. Simon Sandstone thins towards the western edge of the basin. As a result, the highly porous lowermost Mt. Simon section is absent in the western part of the state. - Overall basement dip is from west to east. - Basement topography shows evidence of basement highs with on-lapping patterns by Mt. Simon sediments. - There is evidence of faults within the lower Mt. Simon Sandstone and basement rock that are contemporaneous with Mt. Simon Sandstone deposition. These faults are not active and do not penetrate the Eau Claire Shale. It is believed that these faults are associated with a possible failed rifting event 750 to 560 million years ago during the breakup of the supercontinent Rodinia.

  6. Spin from defects in two-dimensional quantum field theory

    E-Print Network [OSTI]

    Sebastian Novak; Ingo Runkel

    2015-06-24

    We build two-dimensional quantum field theories on spin surfaces starting from theories on oriented surfaces with networks of topological defect lines and junctions. The construction uses a combinatorial description of the spin structure in terms of a triangulation equipped with extra data. The amplitude for the spin surfaces is defined to be the amplitude for the underlying oriented surface together with a defect network dual to the triangulation. Independence of the triangulation and of the other choices follows if the line defect and junctions are obtained from a Delta-separable Frobenius algebra with involutive Nakayama automorphism in the monoidal category of topological defects. For rational conformal field theory we can give a more explicit description of the defect category, and we work out two examples related to free fermions in detail: the Ising model and the so(n) WZW model at level 1.

  7. Spin from defects in two-dimensional quantum field theory

    E-Print Network [OSTI]

    Novak, Sebastian

    2015-01-01

    We build two-dimensional quantum field theories on spin surfaces starting from theories on oriented surfaces with networks of topological defect lines and junctions. The construction uses a combinatorial description of the spin structure in terms of a triangulation equipped with extra data. The amplitude for the spin surfaces is defined to be the amplitude for the underlying oriented surface together with a defect network dual to the triangulation. Independence of the triangulation and of the other choices follows if the line defect and junctions are obtained from a Delta-separable Frobenius algebra with involutive Nakayama automorphism in the monoidal category of topological defects. For rational conformal field theory we can give a more explicit description of the defect category, and we work out two examples related to free fermions in detail: the Ising model and the so(n) WZW model at level 1.

  8. Reconnection events in two-dimensional Hall magnetohydrodynamic turbulence

    SciTech Connect (OSTI)

    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)

    2012-09-15

    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.

  9. Incoherent control and entanglement for two-dimensional coupled systems

    E-Print Network [OSTI]

    R. Romano; D. D'Alessandro

    2005-10-03

    We investigate accessibility and controllability of a quantum system S coupled to a quantum probe P, both described by two-dimensional Hilbert spaces, under the hypothesis that the external control affects only P. In this context accessibility and controllability properties describe to what extent it is possible to drive the state of the system S by acting on P and using the interaction between the two systems. We give necessary and sufficient conditions for these properties and we discuss the relation with the entangling capability of the interaction between S and P. In particular, we show that controllability can be expressed in terms of the SWAP operator, acting on the composite system, and its square root.

  10. High speed two-dimensional optical beam position detector

    SciTech Connect (OSTI)

    Rutten, Paul Edmond

    2011-07-15

    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.

  11. Quantum Emission from Two-Dimensional Black Holes

    E-Print Network [OSTI]

    Steven B. Giddings; W. M. Nelson

    2009-11-27

    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.

  12. Soliton nanoantennas in two-dimensional arrays of quantum dots

    E-Print Network [OSTI]

    Gligori?, G; Had˛ievski, Lj; Slepyan, G Ya; Malomed, B A

    2015-01-01

    We consider two-dimensional (2D) arrays of self-organized semiconductor quantum dots (QDs) strongly interacting with electromagnetic field in the regime of Rabi oscillations. The QD array built of two-level states is modelled by two coupled systems of discrete nonlinear Schr\\"{o}dinger equations. Localized modes in the form of single-peaked fundamental and vortical stationary Rabi solitons and self-trapped breathers have been found. The results for the stability, mobility and radiative properties of the Rabi modes suggest a concept of a self-assembled 2D \\textit{% soliton-based nano-antenna}, which should be stable against imperfections In particular, we discuss the implementation of such a nano-antenna in the form of surface plasmon solitons in graphene, and illustrate possibilities to control their operation by means of optical tools.

  13. Dynamics of a Two-Dimensional System of Quantum Dipoles

    SciTech Connect (OSTI)

    Mazzanti, F.; Astrakharchik, G. E.; Boronat, J.; Zillich, R. E.

    2009-03-20

    A detailed microscopic analysis of the dynamic structure function S(k,{omega}) of a two-dimensional Bose system of dipoles polarized along the direction perpendicular to the plane is presented and discussed. Starting from ground-state quantities obtained using a quantum diffusion Monte Carlo algorithm, the density-density response is evaluated in the context of the correlated basis functions (CBF) theory. CBF predicts a sharp peak and a multiexcitation component at higher energies produced by the decay of excitations. We discuss the structure of the phonon-roton peak and show that the Feynman and Bogoliubov predictions depart from the CBF result already at low densities. We finally discuss the emergence of a roton in the spectrum, but find the roton energy not low enough to make the system unstable under density fluctuations up to the highest density considered that is close to the freezing point.

  14. Approaches to verification of two-dimensional water quality models

    SciTech Connect (OSTI)

    Butkus, S.R. . Water Quality Dept.)

    1990-11-01

    The verification of a water quality model is the one procedure most needed by decision making evaluating a model predictions, but is often not adequate or done at all. The results of a properly conducted verification provide the decision makers with an estimate of the uncertainty associated with model predictions. Several statistical tests are available for quantifying of the performance of a model. Six methods of verification were evaluated using an application of the BETTER two-dimensional water quality model for Chickamauga reservoir. Model predictions for ten state variables were compared to observed conditions from 1989. Spatial distributions of the verification measures showed the model predictions were generally adequate, except at a few specific locations in the reservoir. The most useful statistics were the mean standard error of the residuals. Quantifiable measures of model performance should be calculated during calibration and verification of future applications of the BETTER model. 25 refs., 5 figs., 7 tabs.

  15. Two-dimensional Imaging Velocity Interferometry: Technique and Data Analysis

    SciTech Connect (OSTI)

    Erskine, D J; Smith, R F; Bolme, C; Celliers, P; Collins, G

    2011-03-23

    We describe the data analysis procedures for an emerging interferometric technique for measuring motion across a two-dimensional image at a moment in time, i.e. a snapshot 2d-VISAR. Velocity interferometers (VISAR) measuring target motion to high precision have been an important diagnostic in shockwave physics for many years Until recently, this diagnostic has been limited to measuring motion at points or lines across a target. We introduce an emerging interferometric technique for measuring motion across a two-dimensional image, which could be called a snapshot 2d-VISAR. If a sufficiently fast movie camera technology existed, it could be placed behind a traditional VISAR optical system and record a 2d image vs time. But since that technology is not yet available, we use a CCD detector to record a single 2d image, with the pulsed nature of the illumination providing the time resolution. Consequently, since we are using pulsed illumination having a coherence length shorter than the VISAR interferometer delay ({approx}0.1 ns), we must use the white light velocimetry configuration to produce fringes with significant visibility. In this scheme, two interferometers (illuminating, detecting) having nearly identical delays are used in series, with one before the target and one after. This produces fringes with at most 50% visibility, but otherwise has the same fringe shift per target motion of a traditional VISAR. The 2d-VISAR observes a new world of information about shock behavior not readily accessible by traditional point or 1d-VISARS, simultaneously providing both a velocity map and an 'ordinary' snapshot photograph of the target. The 2d-VISAR has been used to observe nonuniformities in NIF related targets (polycrystalline diamond, Be), and in Si and Al.

  16. Two-Dimensional Electron Gas in Monolayer InN Quantum Wells....

    Office of Scientific and Technical Information (OSTI)

    Two-Dimensional Electron Gas in Monolayer InN Quantum Wells. Citation Details In-Document Search Title: Two-Dimensional Electron Gas in Monolayer InN Quantum Wells. Abstract not...

  17. Designing and Testing a New Shack-Hartmann High Bandwidth Two-Dimensional Wave front Sensor

    E-Print Network [OSTI]

    Gordeyev, Stanislav

    Designing and Testing a New Shack-Hartmann High Bandwidth Two-Dimensional Wave front Sensor Shaddy Dame, Notre Dame, IN 46656 A novel Shack-Hartmann high bandwidth two-dimensional wave front sensor

  18. Electromagnetic Wave Propagation in Two-Dimensional Photonic Crystals

    SciTech Connect (OSTI)

    Stavroula Foteinopoulou

    2003-12-12

    In this dissertation, they have undertaken the challenge to understand the unusual propagation properties of the photonic crystal (PC). The photonic crystal is a medium where the dielectric function is periodically modulated. These types of structures are characterized by bands and gaps. In other words, they are characterized by frequency regions where propagation is prohibited (gaps) and regions where propagation is allowed (bands). In this study they focus on two-dimensional photonic crystals, i.e., structures with periodic dielectric patterns on a plane and translational symmetry in the perpendicular direction. They start by studying a two-dimensional photonic crystal system for frequencies inside the band gap. The inclusion of a line defect introduces allowed states in the otherwise prohibited frequency spectrum. The dependence of the defect resonance state on different parameters such as size of the structure, profile of incoming source, etc., is investigated in detail. For this study, they used two popular computational methods in photonic crystal research, the Finite Difference Time Domain method (FDTD) and the Transfer Matrix Method (TMM). The results for the one-dimensional defect system are analyzed, and the two methods, FDTD and TMM, are compared. Then, they shift their attention only to periodic two-dimensional crystals, concentrate on their band properties, and study their unusual refractive behavior. Anomalous refractive phenomena in photonic crystals included cases where the beam refracts on the ''wrong'' side of the surface normal. The latter phenomenon, is known as negative refraction and was previously observed in materials where the wave vector, the electric field, and the magnetic field form a left-handed set of vectors. These materials are generally called left-handed materials (LHM) or negative index materials (NIM). They investigated the possibility that the photonic crystal behaves as a LHM, and how this behavior relates with the observed negatively refractive phenomena. They found that in the PC system, negative refraction is neither a prerequisite nor guarantees left-handed behavior. They examined carefully the condition to obtain left-handed behavior in the PC. They proposed a wedge type of experiment, in accordance with the experiment performed on the traditional LHM, to test these conditions. They found that for certain frequencies the PC shows left-handed behavior and acts in some respects like a homogeneous medium with a negative refractive index. they used the realistic PC system for this case to show how negative refraction occurs at the interface between a material with a positive and a material with a negative refractive index. Their findings indicate that the formation of the negatively refracted beam is not instantaneous and involves a transient time. With this time-dependent analysis, they were able to address previous controversial issues about negative refraction concerning causality and the speed of light limit. Finally, they attempt a systematic study of anomalous refractive phenomena that can occur at the air-PC interface. They observe cases where only a single refracted beam (in the positive or negative direction) is present, as well as cases with birefringence. they classify these different effects according to their origin and type of propagation (left-handed or not). For a complete study of the system, they also obtain expressions for the energy and group velocities, and show their equality. For cases with very low index contrast, band folding becomes an artificiality. They discuss the validity of their findings when they move to the limit of photonic crystals with a low index modulation.

  19. Two-dimensional state in driven magnetohydrodynamic turbulence

    SciTech Connect (OSTI)

    Bigot, Barbara; Galtier, Sebastien

    2011-02-15

    The dynamics of the two-dimensional (2D) state in driven three-dimensional (3D) incompressible magnetohydrodynamic turbulence is investigated through high-resolution direct numerical simulations and in the presence of an external magnetic field at various intensities. For such a flow the 2D state (or slow mode) and the 3D modes correspond, respectively, to spectral fluctuations in the plane k{sub ||}=0 and in the area k{sub ||}>0. It is shown that if initially the 2D state is set to zero it becomes nonnegligible in few turnover times, particularly when the external magnetic field is strong. The maintenance of a large-scale driving leads to a break for the energy spectra of 3D modes; when the driving is stopped, the previous break is removed and a decay phase emerges with Alfvenic fluctuations. For a strong external magnetic field the energy at large perpendicular scales lies mainly in the 2D state, and in all situations a pinning effect is observed at small scales.

  20. Superfluid behaviour of a two-dimensional Bose gas

    E-Print Network [OSTI]

    Desbuquois, Rémi; Yefsah, Tarik; Léonard, Julian; Beugnon, Jérōme; Weitenberg, Christof; Dalibard, Jean

    2012-01-01

    Two-dimensional (2D) systems play a special role in many-body physics. Because of thermal fluctuations, they cannot undergo a conventional phase transition associated to the breaking of a continuous symmetry. Nevertheless they may exhibit a phase transition to a state with quasi-long range order via the Berezinskii-Kosterlitz-Thouless (BKT) mechanism. A paradigm example is the 2D Bose fluid, such as a liquid helium film, which cannot Bose-condense at non-zero temperature although it becomes superfluid above a critical phase space density. Ultracold atomic gases constitute versatile systems in which the 2D quasi-long range coherence and the microscopic nature of the BKT transition were recently explored. However, a direct observation of superfluidity in terms of frictionless flow is still missing for these systems. Here we probe the superfluidity of a 2D trapped Bose gas with a moving obstacle formed by a micron-sized laser beam. We find a dramatic variation of the response of the fluid, depending on its degre...

  1. Unexpected Stable Two-dimensional Silicon Phosphides with Different Stoichiometries

    SciTech Connect (OSTI)

    Huang, Bing; Zhuang, Houlong; Yoon, Mina; Wei, Su-Huai; Sumpter, Bobby G

    2015-01-01

    The discovery of stable two-dimensional, earth-abundant, semiconducting materials is of great interest and may impact future electronic technologies. By combining global structural prediction and first-principles calculations, we have theoretically discovered several previously unknown semiconducting silicon phosphides (SixPy) monolayers, which could be formed stably at the stoichiometries of y/x1. Unexpectedly, some of these compounds, i.e., P-6m2 Si1P1 and Pm Si1P2, have comparable or even lower formation enthalpies than their previously known bulk allotropes. The band gaps (Eg) of SixPy compounds can be dramatically tuned in an extremely wide range (0< Eg < 3 eV) by simply changing the number of layers or applying an in-plane strain. Moreover, we find that carrier doping can drive the ground state of C2/m Si1P3 from a nonmagnetic state into a robust half-metallic spin-polarized state, originating from its unique valence band structure, which can extend the use of Si-related compounds for spintronics.

  2. Two-dimensional electronic spectroscopy signatures of the glass transition

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

    Lewis, K. L. .M.; Myers, J. A.; Fuller, F.; Tekavec, P. F.; Ogilvie, J. P.

    2010-01-01

    Two-dimensional electronic spectroscopy is a sensitive probe of solvation dynamics. Using a pump–probe geometry with a pulse shaper [ Optics Express 15 (2007), 16681-16689; Optics Express 16 (2008), 17420-17428], we present temperature dependent 2D spectra of laser dyes dissolved in glass-forming solvents. At low waiting times, the system has not yet relaxed, resulting in a spectrum that is elongated along the diagonal. At longer times, the system loses its memory of the initial excitation frequency, and the 2D spectrum rounds out. As the temperature is lowered, the time scale of this relaxation grows, and the elongation persists for longermore »waiting times. This can be measured in the ratio of the diagonal width to the anti-diagonal width; the behavior of this ratio is representative of the frequency–frequency correlation function [ Optics Letters 31 (2006), 3354–3356]. Near the glass transition temperature, the relaxation behavior changes. Understanding this change is important for interpreting temperature-dependent dynamics of biological systems. « less

  3. Terahertz spectroscopy of two-dimensional subwavelength plasmonic structures

    SciTech Connect (OSTI)

    Azad, Abul K; Chen, Houtong; Taylor, Antoinette; O' Hara, John F; Han, Jiaguang; Lu, Xinchao; Zhang, Weili

    2009-01-01

    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.

  4. Kolmogorov flow in two dimensional strongly coupled dusty plasma

    SciTech Connect (OSTI)

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

    2014-07-15

    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?

  5. Two-Dimensional Gas of Massless Dirac Fermions in Graphene

    E-Print Network [OSTI]

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

    2005-09-13

    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.

  6. Ferromagnetism in the two-dimensional periodic Anderson model

    SciTech Connect (OSTI)

    Batista, C. D.; Bonca, J.; Gubernatis, J. E.

    2001-05-01

    Using the constrained-path Monte Carlo method, we studied the magnetic properties of the two-dimensional periodic Anderson model for electron fillings between 1/4 and 1/2. We also derived two effective low-energy theories to assist in interpreting the numerical results. For 1/4 filling, we found that the system can be a Mott or a charge-transfer insulator, depending on the relative values of the Coulomb interaction and the charge-transfer gap between the two noninteracting bands. The insulator may be a paramagnet or antiferromagnet. We concentrated on the effect of electron doping on these insulating phases. Upon doping we obtained a partially saturated ferromagnetic phase for low concentrations of conduction electrons. If the system were a charge-transfer insulator, we would find that the ferromagnetism is induced by the well-known Ruderman-Kittel-Kasuya-Yosida interaction. However, we found a novel correlated hopping mechanism inducing the ferromagnetism in the region where the nondoped system is a Mott insulator. Our regions of ferromagnetism spanned a much smaller doping range than suggested by recent slave boson and dynamical mean-field theory calculations, but they were consistent with that obtained by density-matrix renormalization group calculations of the one-dimensional periodic Anderson model.

  7. Acoustic dispersion in a two-dimensional dipole system

    SciTech Connect (OSTI)

    Golden, Kenneth I.; Kalman, Gabor J.; Donko, Zoltan; Hartmann, Peter [Department of Mathematics and Statistics, College of Engineering and Mathematical Sciences, University of Vermont, Burlington, Vermont 05401-1455 (United States); Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467 (United States); Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary)

    2008-07-15

    We calculate the full density response function and from it the long-wavelength acoustic dispersion for a two-dimensional system of strongly coupled point dipoles interacting through a 1/r{sup 3} potential at arbitrary degeneracy. Such a system has no random-phase-approximation (RPA) limit and the calculation has to include correlations from the outset. We follow the quasilocalized charge (QLC) approach, accompanied by molecular-dynamics (MD) simulations. Similarly to what has been recently reported for the closely spaced classical electron-hole bilayer [G. J. Kalman et al., Phys. Rev. Lett. 98, 236801 (2007)] and in marked contrast to the RPA, we report a long-wavelength acoustic phase velocity that is wholly maintained by particle correlations and varies linearly with the dipole moment p. The oscillation frequency, calculated both in an extended QLC approximation and in the Singwi-Tosi-Land-Sjolander approximation [Phys. Rev. 176, 589 (1968)], is invariant in form over the entire classical to quantum domains all the way down to zero temperature. Based on our classical MD-generated pair distribution function data and on ground-state energy data generated by recent quantum Monte Carlo simulations on a bosonic dipole system [G. E. Astrakharchik et al., Phys. Rev. Lett. 98, 060405 (2007)], there is a good agreement between the QLC approximation kinetic sound speeds and the standard thermodynamic sound speeds in both the classical and quantum domains.

  8. Classical Symmetries of Some Two-Dimensional Models

    E-Print Network [OSTI]

    John H. Schwarz

    1995-03-27

    It is well-known that principal chiral models and symmetric space models in two-dimensional Minkowski space have an infinite-dimensional algebra of hidden symmetries. Because of the relevance of symmetric space models to duality symmetries in string theory, the hidden symmetries of these models are explored in some detail. The string theory application requires including coupling to gravity, supersymmetrization, and quantum effects. However, as a first step, this paper only considers classical bosonic theories in flat space-time. Even though the algebra of hidden symmetries of principal chiral models is confirmed to include a Kac--Moody algebra (or a current algebra on a circle), it is argued that a better interpretation is provided by a doubled current algebra on a semi-circle (or line segment). Neither the circle nor the semi-circle bears any apparent relationship to the physical space. For symmetric space models the line segment viewpoint is shown to be essential, and special boundary conditions need to be imposed at the ends. The algebra of hidden symmetries also includes Virasoro-like generators. For both principal chiral models and symmetric space models, the hidden symmetry stress tensor is singular at the ends of the line segment.

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

    SciTech Connect (OSTI)

    Carlson, M.W.

    1990-01-01

    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.

  10. Two-dimensional defect modes in optically induced photonic lattices

    SciTech Connect (OSTI)

    Wang Jiandong; Yang Jianke; Chen Zhigang [Department of Mathematics and Statistics, University of Vermont, Burlington, Vermont 05401 (United States); Department of Physics and Astronomy, San Francisco State University, San Francisco, California 94132 (United States)

    2007-07-15

    In this article, localized linear defect modes due to band gap guidance in two-dimensional photonic lattices with localized or nonlocalized defects are investigated theoretically. First, when the defect is localized and weak, eigenvalues of defect modes bifurcated from edges of Bloch bands are derived analytically. It is shown that in an attractive (repulsive) defect, defect modes bifurcate out from Bloch-band edges with normal (anomalous) diffraction coefficients. Furthermore, distances between defect-mode eigenvalues and Bloch-band edges decrease exponentially with the defect strength, which is very different from the one-dimensional case where such distances decrease quadratically with the defect strength. It is also found that some defect-mode branches bifurcate not from Bloch-band edges, but from quasiedge points within Bloch bands, which is very unusual. Second, when the defect is localized but strong, defect modes are determined numerically. It is shown that both the repulsive and attractive defects can support various types of defect modes such as fundamental, dipole, quadrupole, and vortex modes. These modes reside in various band gaps of the photonic lattice. As the defect strength increases, defect modes move from lower band gaps to higher ones when the defect is repulsive, but remain within each band gap when the defect is attractive, similar to the one-dimensional case. The same phenomena are observed when the defect is held fixed while the applied dc field (which controls the lattice potential) increases. Lastly, if the defect is nonlocalized (i.e., it persists at large distances in the lattice), it is shown that defect modes can be embedded inside the continuous spectrum, and they can bifurcate out from edges of the continuous spectrum algebraically rather than exponentially.

  11. Synthesis of Two-Dimensional Materials by Selective Extraction

    SciTech Connect (OSTI)

    Abdelmalak, Michael Naguib; Gogotsi, Yury

    2015-01-01

    Two-dimensional (2D) materials have attracted much attention in the past decade. They offer high specific surface area, as well as electronic structure and properties that differ from their bulk counterparts due to the low dimensionality. Graphene is the best known and the most studied 2D material, but metal oxides and hydroxides (including clays), dichalcogenides, boron nitride (BN), and other materials that are one or several atoms thick are receiving increasing attention. They may deliver a combination of properties that cannot be provided by other materials. The most common synthesis approach in general is by reacting different elements or compounds to form a new compound. However, this approach does not necessarily work well for low-dimensional structures, since it favors formation of energetically preferred 3D (bulk) solids. Many 2D materials are produced by exfoliation of van der Waals solids, such as graphite or MoS2, breaking large particles into 2D layers. However, these approaches are not universal; for example, 2D transition metal carbides cannot be produced by any of them. An alternative but less studied way of material synthesis is the selective extraction process, which is based on the difference in reactivity and stability between the different components (elements or structural units) of the original material. It can be achieved using thermal, chemical, or electrochemical processes. Many 2D materials have been synthesized using selective extraction, such as graphene from SiC, transition metal oxides (TMO) from layered 3D salts, and transition metal carbides or carbonitrides (MXenes) from MAX phases. Selective extraction synthesis is critically important when the bonds between the building blocks of the material are too strong (e.g., in carbides) to be broken mechanically in order to form nanostructures. Unlike extractive metallurgy, where the extracted metal is the goal of the process, selective extraction of one or more elements from the precursor materials releases 2D structures. In this Account, in addition to graphene and TMO, we focused on MXenes as an example for the use of selective extraction synthesis to produce novel 2D materials. About 10 new carbides and carbonitrides of transition metals have been produced by this method in the past 3 years. They offer an unusual combination of metallic conductivity and hydrophilicity and show very attractive electrochemical properties. We hope that this Account will encourage researchers to extend the use of selective extraction to other layered material systems that in turn will result in expanding the world of nanomaterials in general and 2D materials in particular, generating new materials that cannot be produced by other means.

  12. Phase-sensitive two-dimensional neutron shearing interferometer and Hartmann sensor

    DOE Patents [OSTI]

    Baker, Kevin

    2015-12-08

    A neutron imaging system detects both the phase shift and absorption of neutrons passing through an object. The neutron imaging system is based on either of two different neutron wavefront sensor techniques: 2-D shearing interferometry and Hartmann wavefront sensing. Both approaches measure an entire two-dimensional neutron complex field, including its amplitude and phase. Each measures the full-field, two-dimensional phase gradients and, concomitantly, the two-dimensional amplitude mapping, requiring only a single measurement.

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

    SciTech Connect (OSTI)

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

    2014-09-01

    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.

  14. A characterization of causal automorphisms on two-dimensional Minkowski spacetime

    E-Print Network [OSTI]

    Do-Hyung Kim

    2013-04-08

    It is shown that causal automorphisms on two-dimensional Minkowski spacetime can be characterized by the invariance of the wave equations.

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

    E-Print Network [OSTI]

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

    2014-01-01

    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

  16. Three-Dimensional Seismic Imaging of the Ryepatch Geothermal Reservoir

    E-Print Network [OSTI]

    Feighner, Mark A.

    2010-01-01

    at Well 46-28, Rye Patch Geothermal Field, Pershing County,Seismic Survey, Rye Patch Geothermal Field, Pershing County,Seismic Survey, Rye Patch Geothermal Field, Pershing County,

  17. Effective mass enhancement of two-dimensional electrons in a one-dimensional superlattice potential

    E-Print Network [OSTI]

    Rokhinson, Leonid

    Effective mass enhancement of two-dimensional electrons in a one-dimensional superlattice potential effective mass enhancement of two-dimensional 2D electrons in an atomically precise one-dimensional Al reveal that the mobility of the 2D electrons increases with electron density n2D . At low densities (n2D

  18. Magnetoconductivity of two-dimensional electrons on liquid helium: Experiments in the fluid phase

    E-Print Network [OSTI]

    Fang-Yen, Christopher

    Magnetoconductivity of two-dimensional electrons on liquid helium: Experiments in the fluid phase M of Electronics and Computer Science, University of Southampton, SO17 1BJ, England Received 16 May 1996; revised manuscript received 25 November 1996 The magnetoconductivity (B) of two-dimensional electrons on liquid

  19. Flow transitions in two-dimensional foams Christopher Gilbreth, Scott Sullivan, and Michael Dennin

    E-Print Network [OSTI]

    Dennin, Michael

    Flow transitions in two-dimensional foams Christopher Gilbreth, Scott Sullivan, and Michael Dennin: November 21, 2006) For sufficiently slow rates of strain, flowing foam can exhibit inhomogeneous flows. The nature of these flows is an area of active study in both two-dimensional model foams and three

  20. Negative linear classical magnetoresistance in a corrugated two-dimensional electron gas N. M. Sotomayor*

    E-Print Network [OSTI]

    Gusev, Guennady

    Negative linear classical magnetoresistance in a corrugated two-dimensional electron gas N. M (Received 18 August 2004; published 20 December 2004) Large linear negative magnetoresistance (LNMR) was measured in a GaAs/AlxGa1-xAs two-dimensional electron system with nonplanar topography, caused by random

  1. Surface energies in a two-dimensional mass-spring model for crystals

    E-Print Network [OSTI]

    Theil, Florian

    Surface energies in a two-dimensional mass-spring model for crystals Florian Theil Mathematics an atomistic pair potential-energy E(n)(y) that describes the elastic behavior of two- dimensional crystals analysis of the ground state energy as n tends to infinity. We show in a suitable scaling regime where

  2. TWO-DIMENSIONAL TRANSIENT RADIATIVE HEAT TRANSFER USING DISCRETE ORDINATES METHOD

    E-Print Network [OSTI]

    Guo, Zhixiong "James"

    TWO-DIMENSIONAL TRANSIENT RADIATIVE HEAT TRANSFER USING DISCRETE ORDINATES METHOD Zhixiong Guo for the first time to solve transient radiative heat transfer in a two-dimensional rectangular enclosure of solution method of radiative heat transfer in participating media in recent decades. However, the analysis

  3. Energy and enstrophy transfer in numerical simulations of two-dimensional' turbulence

    E-Print Network [OSTI]

    Vallis, Geoff

    Energy and enstrophy transfer in numerical simulations of two-dimensional' turbulence Mathew E a significant fraction of the flow field,w and energy spectra from these simulations have slopes significantly October 1992; accepted 25 March 1993) Numerical simulations of statistically steady two-dimensional (2-D

  4. Energy localization and transport in two-dimensional electrical L.Q. English1

    E-Print Network [OSTI]

    Carretero, Ricardo

    Energy localization and transport in two-dimensional electrical lattices L.Q. English1 , F. Palmero and characterized in two-dimensional nonlinear electrical lattices which were driven by a spatially-uniform voltage-dimensional, damped-driven electrical lattices (see also Ref. [12]). We characterize these breather states

  5. Phonons in two-dimensional soft colloidal crystals Ke Chen,1, 2

    E-Print Network [OSTI]

    Schindler, Michael

    Phonons in two-dimensional soft colloidal crystals Ke Chen,1, 2 Tim Still,1 Samuel Schoenholz,1 and polycrystalline monolayer colloidal crystals composed of thermosensitive microgel particles are measured using-frequency modes in polycrystalline two-dimensional colloidal crystals are identified and demonstrated to correlate

  6. Two-dimensional Insect Flight on an Air-Water Interface is a Chaotic Oscillator

    E-Print Network [OSTI]

    Mukundarajan, Haripriya; Prakash, Manu

    2014-01-01

    Two-dimensional flapping wing insect flight on an air-water interface provides a successful foraging strategy to explore an ecological niche on the surface of a pond. However, the complex interplay of surface tension, aerodynamic forces, biomechanics and neural control that enables two-dimensional flight is unknown. Here we report the discovery of two-dimensional flight in the waterlily beetle Galerucella nymphaeae, which is the fastest reported propulsion mode for an insect on a fluid interface. Using kinematics derived from high-speed videography coupled with analytical models, we demonstrate that two-dimensional flight is a chaotic interfacial oscillator, thus significantly constraining the possible range of flight parameters. Discovery of this complex dynamics in two-dimensional flight on time scales similar to neural responses indicates the challenge of evolving active flight control on a fluid interface.

  7. Exact solutions of a two-dimensional Kemmer oscillator in the gravitational field of cosmic string

    E-Print Network [OSTI]

    Nadjette. Messai; Abdelmalek. Boumali

    2015-04-21

    The two dimensional Kemmer oscillator under the influence of the gravitational field produced by a topology such as the cosmic string spacetime and in the presence of a uniform magnetic field as well as without magnetic field are investigated.

  8. Terahertz waveguide spectroscopy of two-dimensional plasmons in GaAs

    E-Print Network [OSTI]

    Harris, C. Thomas (Charles Thomas)

    2010-01-01

    The electrical characteristics of high-mobility, two-dimensional electron gas (2DEG) systems, such as GaAs quantum wells, have been well-studied at low frequencies and in extreme conditions of high magnetic fields and ...

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

    E-Print Network [OSTI]

    Cooke, Michele

    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

  10. Diagnosing Chaos Using Four-Point Functions in Two-Dimensional Conformal Field Theory

    E-Print Network [OSTI]

    Stanford, Douglas

    We study chaotic dynamics in two-dimensional conformal field theory through out-of-time-order thermal correlators of the form ?W(t)VW(t)V?. We reproduce holographic calculations similar to those of Shenker and Stanford, ...

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

    E-Print Network [OSTI]

    Coral Pinto, Raul Javier

    2005-01-01

    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. ...

  12. Traveling Wave Solutions for Systems of ODEs on a Two-Dimensional Spatial Lattice

    E-Print Network [OSTI]

    Van Vleck, Erik; Mallet-Paret, John; Cahn, John W.

    1999-03-05

    We consider infinite systems of ODEs on the two-dimensional integer lattice, given by a bistable scalar ODE at each point, with a nearest neighbor coupling between lattice points. For a class of ideal nonlinearities, we ...

  13. Coherent two-exciton dynamics measured using two-quantum rephasing two-dimensional electronic spectroscopy

    E-Print Network [OSTI]

    Turner, Daniel B.

    We use fifth-order two-dimensional electronic spectroscopy to measure coherent four-particle dynamics in a semiconductor nanostructure. By using optical polarization control in two-quantum measurements enabled by the COLBERT ...

  14. Comparative Visualization of Two-Dimensional Flow Data Using Moment Invariants

    E-Print Network [OSTI]

    Hamann, Bernd

    Comparative Visualization of Two-Dimensional Flow Data Using Moment Invariants author1, author2 affiliation1 affiliation2 Email: {author1,author2}@affiliation Abstract The analysis of time-dependent data

  15. A tale of coupled vibrations in solution told by coherent two-dimensional infrared spectroscopy

    E-Print Network [OSTI]

    Khalil, Munira, 1975-

    2004-01-01

    Coherent two-dimensional infrared (2D IR) spectroscopy is used as a tool for investigating the molecular structure and dynamics of coupled vibrations in solution on a picosecond timescale. The strongly coupled asymmetric ...

  16. Parametric resonance of a two-dimensional electron gas under bichromatic irradiation Christian Joas

    E-Print Network [OSTI]

    von Oppen, Felix

    Parametric resonance of a two-dimensional electron gas under bichromatic irradiation Christian Joas driving ac fields (bichromatic irradiation). Compared to the case of monochromatic irradiation, which's theorem, gives rise to new qualitative effects specific to bichromatic irradiation. Namely, when

  17. A TWO-DIMENSIONAL FEM CODE FOR THE ANALYSIS OF LARGE DEFORMATIONS OF

    E-Print Network [OSTI]

    Zabaras, Nicholas J.

    A TWO-DIMENSIONAL FEM CODE FOR THE ANALYSIS OF LARGE DEFORMATIONS OF HYPERELASTIC VISCOPLASTIC, a hyper elastic formulation was considered by Weber and Anand 3]. In this work, the elasticity is modelled

  18. Two-Dimensional Image Rotation Ivan Sterling 1 and Thomas Sterling 2

    E-Print Network [OSTI]

    Sterling, Ivan

    Two-Dimensional Image Rotation Ivan Sterling 1 and Thomas Sterling 2 1 Department of Mathematics scanning of a document, such as an engineering drawing. When the drawing is fed into the scanner, it may

  19. Stability Studies of Two-dimensional Magnetic Bernstein-Greene-Kruskal Modes using PIC Simulations

    E-Print Network [OSTI]

    Ng, Chung-Sang

    Stability Studies of Two-dimensional Magnetic Bernstein- Greene-Kruskal Modes using PIC Simulations of these solutions, as well as Particle-in-Cell (PIC) simulations, we will present further studies of the stability

  20. The Electronic Structure of a Two-Dimensional Pure Copper Oxide...

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

    the two-dimensional (2D) CuO2 planes. By growing epitaxial films with the pulsed-laser deposition facility available on Beamline 7.0.1, researchers could stabilize a 2D version...

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

    E-Print Network [OSTI]

    Donahue, Neil M.

    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 ...

  2. Long-wavelength anomalous diffusion mode in the two-dimensional XY dipole magnet 

    E-Print Network [OSTI]

    Abanov, Artem; Kashuba, A.; Pokrovsky, Valery L.

    1997-01-01

    In a two-dimensional XY ferromagnet the dipole force induces a strong interaction between spin waves in the long-wavelength limit. The major effect of this interaction is the transformation of a propagating spin wave into ...

  3. Two dimensional electron transport in modulation-doped In{sub...

    Office of Scientific and Technical Information (OSTI)

    Two dimensional electron transport in modulation-doped Insub 0.53Gasub 0.47AsAlAssub 0.56Sbsub 0.44 ultrathin quantum wells Citation Details In-Document Search Title: Two...

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

    E-Print Network [OSTI]

    Jovanovic, Natalija Zorana

    2005-01-01

    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 ...

  5. Volumetric reconstruction of tissue structure from two-dimensional microscopy images

    E-Print Network [OSTI]

    Cruz, Francisco (Francisco Ui)

    2006-01-01

    Cell morphology of tissue is naturally three-dimensional. Most current methods for tissue analysis use two dimensional histological images of the tissue samples, restricting the analysis to 2D. Existing approaches do not ...

  6. Modeling of acoustic wave scattering from a two-dimensional fracture

    E-Print Network [OSTI]

    Wang, Ping

    2010-01-01

    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 ...

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

    SciTech Connect (OSTI)

    Soni, Himadri R. Jha, Prafulla K.

    2014-04-24

    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.

  8. Correlational properties of two-dimensional solvable chaos on the unit circle

    E-Print Network [OSTI]

    Aki-Hiro Sato; Ken Umeno

    2012-08-30

    This article investigates correlational properties of two-dimensional chaotic maps on the unit circle. We give analytical forms of higher-order covariances. We derive the characteristic function of their simultaneous and lagged ergodic densities. We found that these characteristic functions are described by three types of two-dimensional Bessel functions. Higher-order covariances between x and y and those between y and y show non-positive values. Asymmetric features between cosine and sine functions are elucidated.

  9. Development and validation of a vertically two-dimensional mesoscale numerical model 

    E-Print Network [OSTI]

    Walters, Michael Kent

    1985-01-01

    DEVELOPMENT AND VALIDATION OF A VERTICALLY TWO-DIMENSIONAL MESOSCALE NUMERICAL MODEL A Thesis by MICHAEL KENT WALTERS Submitted to the Graduate College of Texas AsM University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE August 1985 Major Subject: Meteorology DEVELOPMENT AND VALIDATION OF A VERTICALLY TWO-DIMENSIONAL MESOSCALE NUMERICAL MODEL A Thesis by MICHAEL KENT WALTERS Approved as to style and content by: Dusan Djuric (Chair of Committee) WP...

  10. Lyapunov Modes and Time-Correlation Functions for Two-Dimensional Systems

    E-Print Network [OSTI]

    Tooru Taniguchi; Gary P. Morriss

    2005-09-27

    The relation between the Lyapunov modes (delocalized Lyapunov vectors) and the momentum autocorrelation function is discussed in two-dimensional hard-disk systems. We show numerical evidence that the smallest time-oscillating period of the Lyapunov modes is twice as long as the time-oscillating period of momentum autocorrelation function for both square and rectangular two-dimensional systems with hard-wall boundary conditions.

  11. An Archaeological Survey for Cross Bayou Exploration's Midway 3-D Seismic Survey in the Kisatchie National Forest in Webster Parish, Louisiana 

    E-Print Network [OSTI]

    Moore, William; Baxter, Edward

    2015-07-30

    A Phase I cultural resources survey of a 0.59 square mile area (375 acres) within the Caney Ranger District of the Kisatchie National Forest in central Webster Parish, Louisiana was conducted by Dixie Environmental Services Co., LP (DESCO) under...

  12. Two-dimensional electron gas in monolayer InN quantum wells

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

    Pan, Wei; Dimakis, Emmanouil; Wang, George T.; Moustakas, Theodore D.; Tsui, Daniel C.

    2014-11-24

    We report in this letter experimental results that confirm the two-dimensional nature of the electron systems in monolayer InN quantum wells embedded in GaN barriers. The electron density and mobility of the two-dimensional electron system (2DES) in these InN quantum wells are 5×1015 cm-2 and 420 cm2 /Vs, respectively. Moreover, the diagonal resistance of the 2DES shows virtually no temperature dependence in a wide temperature range, indicating the topological nature of the 2DES.

  13. Quantum Monte Carlo simulation of a two-dimensional Bose gas

    SciTech Connect (OSTI)

    Pilati, S.; Boronat, J.; Casulleras, J.; Giorgini, S.

    2005-02-01

    The equation of state of a homogeneous two-dimensional Bose gas is calculated using quantum Monte Carlo methods. The low-density universal behavior is investigated using different interatomic model potentials, both finite ranged and strictly repulsive and zero ranged, supporting a bound state. The condensate fraction and the pair distribution function are calculated as a function of the gas parameter, ranging from the dilute to the strongly correlated regime. In the case of the zero-range pseudopotential we discuss the stability of the gaslike state for large values of the two-dimensional scattering length, and we calculate the critical density where the system becomes unstable against cluster formation.

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

    DOE Patents [OSTI]

    Schiek, Richard (Albuquerque, NM)

    2006-06-20

    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.

  15. Hydrogenated Bilayer Wurtzite SiC Nanofilms: A Two-Dimensional Bipolar Magnetic Semiconductor Material

    E-Print Network [OSTI]

    Yuan, Long; Yang, Jinlong

    2012-01-01

    Recently, a new kind of spintronics materials, bipolar magnetic semiconductor (BMS), has been proposed. The spin polarization of BMS can be conveniently controlled by a gate voltage, which makes it very attractive in device engineering. Now, the main challenge is finding more BMS materials. In this article, we propose that hydrogenated wurtzite SiC nanofilm is a two-dimensional BMS material. Its BMS character is very robust under the effect of strain, substrate, or even a strong electric field. The proposed two-dimensional BMS material paves the way to use this promising new material in an integrated circuit.

  16. Seismic event classification system

    DOE Patents [OSTI]

    Dowla, Farid U. (Castro Valley, CA); Jarpe, Stephen P. (Brentwood, CA); Maurer, William (Livermore, CA)

    1994-01-01

    In the computer interpretation of seismic data, the critical first step is to identify the general class of an unknown event. For example, the classification might be: teleseismic, regional, local, vehicular, or noise. Self-organizing neural networks (SONNs) can be used for classifying such events. Both Kohonen and Adaptive Resonance Theory (ART) SONNs are useful for this purpose. Given the detection of a seismic event and the corresponding signal, computation is made of: the time-frequency distribution, its binary representation, and finally a shift-invariant representation, which is the magnitude of the two-dimensional Fourier transform (2-D FFT) of the binary time-frequency distribution. This pre-processed input is fed into the SONNs. These neural networks are able to group events that look similar. The ART SONN has an advantage in classifying the event because the types of cluster groups do not need to be pre-defined. The results from the SONNs together with an expert seismologist's classification are then used to derive event classification probabilities.

  17. Seismic event classification system

    DOE Patents [OSTI]

    Dowla, F.U.; Jarpe, S.P.; Maurer, W.

    1994-12-13

    In the computer interpretation of seismic data, the critical first step is to identify the general class of an unknown event. For example, the classification might be: teleseismic, regional, local, vehicular, or noise. Self-organizing neural networks (SONNs) can be used for classifying such events. Both Kohonen and Adaptive Resonance Theory (ART) SONNs are useful for this purpose. Given the detection of a seismic event and the corresponding signal, computation is made of: the time-frequency distribution, its binary representation, and finally a shift-invariant representation, which is the magnitude of the two-dimensional Fourier transform (2-D FFT) of the binary time-frequency distribution. This pre-processed input is fed into the SONNs. These neural networks are able to group events that look similar. The ART SONN has an advantage in classifying the event because the types of cluster groups do not need to be pre-defined. The results from the SONNs together with an expert seismologist's classification are then used to derive event classification probabilities. 21 figures.

  18. Symmetry operators for Dirac's equation on two-dimensional spin manifolds

    E-Print Network [OSTI]

    Lorenzo Fatibene; Raymond G. McLenaghan; Giovanni Rastelli; Shane N. Smith

    2008-12-17

    It is shown that the second order symmetry operators for the Dirac equation on a general two-dimensional spin manifold may be expressed in terms of Killing vectors and valence two Killing tensors. The role of these operators in the theory of separation of variables for the Dirac equation is studied.

  19. Gravity Effects on Steady Two-Dimensional Partially Premixed MethaneAir Flames

    E-Print Network [OSTI]

    Aggarwal, Suresh K.

    Gravity Effects on Steady Two-Dimensional Partially Premixed Methane­Air Flames ZHUANG SHU, CHUN W, University of Illinois at Chicago, Chicago, IL 60607-7022 Under normal-gravity conditions the flame heat is only weakly affected by gravity, the outer flame shows significant spatial differences for the two

  20. Solar thermophotovoltaic energy conversion systems with two-dimensional tantalum photonic crystal absorbers and emitters

    E-Print Network [OSTI]

    Soljačię, Marin

    Solar thermophotovoltaic energy conversion systems with two-dimensional tantalum photonic crystal) systems convert solar energy into electricity via thermally radiated photons at tailored wavelengths highly scalable for a wide range of power capacities, have no moving parts, and allow solar energy

  1. Cut-wire-pair structures as two-dimensional magnetic metamaterials

    E-Print Network [OSTI]

    Cut-wire-pair structures as two-dimensional magnetic metamaterials David A. Powell, Ilya V-dimensional metamaterial suitable for scaling to optical frequencies. We fabricate the cut-wire metamaterial operating. © 2008 Optical Society of America OCIS codes: (160.3918) Metamaterials; (350.4010) Microwaves References

  2. Nonexistence of Coherent Structures in Two-Dimensional Inviscid Channel Flow

    E-Print Network [OSTI]

    Kalisch, Henrik

    Abstract Two-dimensional inviscid channel flow of an incompressible fluid is considered. It is shown to the study of transition from laminar flow to turbulence [25]. It follows from the result of this note that this kind of steady flow cannot exist in an inviscid fluid. Imagine a fluid contained in a horizontal

  3. Formation of Two-Dimensional Sand Ripples under Laminar Shear Flow Vincent Langlois and Alexandre Valance

    E-Print Network [OSTI]

    Formation of Two-Dimensional Sand Ripples under Laminar Shear Flow Vincent Langlois and Alexandre sand bed patterns under a laminar and steady shear flow. Several issues are addressed here: (i fluid is investigated theoretically. The sand transport is described taking into account both the local

  4. PennyPacking and TwoDimensional Codes * R. L. Graham and N. J. A. Sloane

    E-Print Network [OSTI]

    Sloane, Neil J. A.

    design, when the points P 1 , . . . , P n form a two­dimensional code [3], [4], [7], U measures of the best packings known for n £ 500. For large n, U ~ Ö``3 n 2 / (4p). _______________ * This appeared diameter d, let P 1 , . . . , P n be their centers and P __ = n - 1 S P i their centroid. Then the problem

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

    E-Print Network [OSTI]

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

    2005-01-01

    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...

  6. Two-dimensional Gibbsian point processes with continuous spin-symmetries

    E-Print Network [OSTI]

    Thomas Richthammer

    2004-07-13

    We consider two-dimensional marked point processes which are Gibbsian with a two-body-potential U. U is supposed to have an internal continuous symmetry. We show that under suitable continuity conditions the considered processes are invariant under the given symmetry. We will achieve this by using Ruelle`s superstability estimates and percolation arguments.

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

    E-Print Network [OSTI]

    Fayer, Michael D.

    Water Dynamics in Salt Solutions Studied with Ultrafast Two-Dimensional Infrared (2D IR. Many of these species are charged. In the ocean, water interacts with dissolved salts. In biological systems, water interacts with dissolved salts as well as charged amino acids, the zwitterionic head groups

  8. The anomaly-free quantization of two-dimensional relativistic string. I

    E-Print Network [OSTI]

    S. N. Vergeles

    1998-12-21

    An anomaly-free quantum theory of a relativistic string is constructed in two-dimensional space-time. The states of the string are found to be similar to the states of a massless chiral quantum particle. This result is obtained by generalizing the concept of an ``operator'' in quantum field theory.

  9. Two-dimensional Thermomechanical Analysis and Optimization of Functionally Graded Materials

    E-Print Network [OSTI]

    Vel, Senthil

    Two-dimensional Thermomechanical Analysis and Optimization of Functionally Graded Materials Andrew optimization of heat resisting metal/ceramic functionally graded materials (FGMs). The plane stress static thermoelastic behavior of a FGM is analyzed using the element-free Galerkin method. The effective material

  10. Two-dimensional optimization of material composition of functionally graded materials using meshless analyses

    E-Print Network [OSTI]

    Vel, Senthil

    Two-dimensional optimization of material composition of functionally graded materials using-dimensional simulation and optimization of material distribution of functionally graded materials for thermomechanical to optimize the material composition for two model problems. In the first problem, we minimize the peak

  11. SOME OBSERVATIONS OF TWO-DIMENSIONAL SMOLDERING AND THE TRANSITION TO FLAMING

    E-Print Network [OSTI]

    Tse, Stephen D.

    process from slow smoldering to rapid flaming (fast, exothermic, gas-phase reactions) is also689 SOME OBSERVATIONS OF TWO-DIMENSIONAL SMOLDERING AND THE TRANSITION TO FLAMING Stephen D. Tse and the phenomenon of transition to flaming of a porous combustible material in the presence of an air

  12. Two-dimensional high-bandwidth Shack-Hartmann wavefront sensor

    E-Print Network [OSTI]

    Gordeyev, Stanislav

    Two-dimensional high-bandwidth Shack-Hartmann wavefront sensor: design guidelines and evaluation-dimensional high-bandwidth Shack-Hartmann wavefront sensor was designed and tested, addressing the high tempo- ral Engineers. DOI: 10.1117/1.3454383 Subject terms: aero-optics; Shack-Hartmann; wavefront sensor; adaptive

  13. Two dimensional silicon nanowalls for lithium ion Jiayu Wan,a

    E-Print Network [OSTI]

    Li, Teng

    batteries are one of the most important electrochemical energy storage devices and are widely usedTwo dimensional silicon nanowalls for lithium ion batteries Jiayu Wan,a Alex F. Kaplan,b Jia Zheng with silicon for Li-ion batteries. Excellent performance for the first Coulombic efficiency (CE) has been

  14. Patterning Proteins and Cells Using Two-Dimensional Arrays of Colloids

    E-Print Network [OSTI]

    Aksay, Ilhan A.

    Patterning Proteins and Cells Using Two-Dimensional Arrays of Colloids Nathaniel J. Gleason with proteins are deposited onto coverslips coated with gold using a combination of gravitational settling of particles on the substrate. Surface coverage ranged from an essentially continuous coating of protein

  15. Two-dimensional imaging of continuous-wave terahertz radiation using electro-optic detection

    E-Print Network [OSTI]

    Heinz, Tony F.

    image the two-dimensional properties of a THz beam focused into a 110 ZnTe electro-optic detection- though x-ray imaging has found significant application in medical diagnostics. As one moves further as a function of the spatial posi- tion of the beam. In order to create an image, one then mea- sures

  16. Passive tracer patchiness and particle trajectory stability in incompressible two-dimensional flows

    E-Print Network [OSTI]

    Olascoaga, Maria Josefina

    Passive tracer patchiness and particle trajectory stability in incompressible two-dimensional flows in Geophysics (2003) 1:1­8 Nonlinear Processes in Geophysics c European Geophysical Society 2003 Passive tracer." This leads to patchiness in the evolution of passive tracer distribu- tions. Also, it is argued

  17. Optimization of a Flyback Transformer Winding Considering Two-Dimensional Field Effects, Cost

    E-Print Network [OSTI]

    Optimization of a Flyback Transformer Winding Considering Two-Dimensional Field Effects, Cost and perhaps miti- gated. And both the cost and the loss in the litz-wire winding are strong functions and cost. In this paper, we address just such a case: a flyback trans- 1Although high-frequency winding

  18. Two-dimensional simulations of extreme floods on a large watershed

    E-Print Network [OSTI]

    Julien, Pierre Y.

    Two-dimensional simulations of extreme floods on a large watershed John F. England Jr. a,*, Mark L. Velleux b , Pierre Y. Julien c a Bureau of Reclamation, Flood Hydrology, 86-68530, Denver Federal Center September 2007; accepted 14 September 2007 KEYWORDS Flash floods; Flood design; Rainfall runoff; Extreme

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

    SciTech Connect (OSTI)

    Rezayi, Edward

    2013-07-25

    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.

  20. Transitions in two-dimensional patterns in a ferrocyanideiodatesulfite Qi Ouyang, and Harry L. Swinney

    E-Print Network [OSTI]

    Transitions in two-dimensional patterns in a ferrocyanide­iodate­sulfite reaction Ge Li,a) Qi-dimensional 2D spatial patterns were investigated in a ferrocyanide­iodate­ sulfite FIS reaction in a circular.2­0.6 mm , reservoir residence time 0.6­4 min , and ferrocyanide concentration 12­80 mM . Iodate

  1. Fifth-order electronically non-resonant Raman scattering: two-dimensional Fourier deconvolution

    E-Print Network [OSTI]

    Kaufman, Laura

    Fifth-order electronically non-resonant Raman scattering: two-dimensional Fourier deconvolution information on the direct ®fth-order nuclear response as well as the hyper- polarizability responses can-resonant Raman scattering is one of the new multi-dimensional spectroscopic techniques that oers information

  2. Modelling dynamics of piezoelectric solids in the two-dimensional case

    E-Print Network [OSTI]

    Melnik, Roderick

    that may not be attained by purely electronic means. These new horizons of piezoelectric applicationsModelling dynamics of piezoelectric solids in the two-dimensional case R.V.N. Melnik a,*, K; Hollow piezoceramic cylinders; Corner points; Accuracy estimates 1. Introduction In many applications

  3. Structural Health Monitoring of Composite Materials Using the Two Dimensional Fast Fourier

    E-Print Network [OSTI]

    Nemat-Nasser, Sia

    Structural Health Monitoring of Composite Materials Using the Two Dimensional Fast Fourier. This work is part of an effort to develop smart composite materials that monitor their own health using the health of composite materials. Submitted to: Smart Materials and Structures #12;Structural Health

  4. Quantum dots and etch-induced depletion of a silicon two-dimensional electron gas

    E-Print Network [OSTI]

    Coppersmith, Susan N.

    Quantum dots and etch-induced depletion of a silicon two-dimensional electron gas L. J. Klein, K. L coupled quantum dots containing individual electrons whose spins act as qubits.4 We have made recent in a silicon quantum dot can be held constant for up to 11 hours. This fulfills an important milestone towards

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

    E-Print Network [OSTI]

    Mukamel, Shaul

    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

  6. Modeling the patterned two-dimensional electron gas: Electrostatics John H. Davies and Ivan A. Larkin

    E-Print Network [OSTI]

    Davies, John H.

    Modeling the patterned two-dimensional electron gas: Electrostatics John H. Davies and Ivan A. V. Sukhorukov Institute of Problems of Microelectronics Technology, Academy of Science of Russia, Chernogolovka, Moscow district, Russia, 142432 (Dated: February 21, 2005) Abstract We present analytical

  7. TWO-DIMENSIONAL COMPRESSION OF SURFACE ELECTROMYOGRAPHIC SIGNALS USING COLUMN-CORRELATION SORTING AND IMAGE ENCODERS

    E-Print Network [OSTI]

    Carvalho, Joćo Luiz

    TWO-DIMENSIONAL COMPRESSION OF SURFACE ELECTROMYOGRAPHIC SIGNALS USING COLUMN-CORRELATION SORTING of Computer Science. chaffim@gmail.com INTRODUCTION Surface Electromyographic (S-EMG) signals are important different approaches have been proposed for compression of electromyographic signals, including DPCM [3

  8. The critical velocity for vortex existence in a two dimensional rotating Bose-Einstein condensate

    E-Print Network [OSTI]

    Ignat, Radu

    The critical velocity for vortex existence in a two dimensional rotating Bose-Einstein condensate-Einstein condensate. It consists in minimizing a Gross-Pitaevskii functional defined in R2 under the unit mass constraint. We estimate the critical rotational speed 1 for vortex existence in the bulk of the condensate

  9. Electrostatic Structures in Space Plasmas: Properties of Two-dimensional Magnetic

    E-Print Network [OSTI]

    Ng, Chung-Sang

    Electrostatic Structures in Space Plasmas: Properties of Two-dimensional Magnetic Bernstein-Greene without background B #12;Electron dynamics with uniform ion background #12;Solutions with only energy, it actually has less total energy than that of a Maxwellian plasma. Difference in total energy between

  10. Electrostatic Structures in Space Plasmas: Properties of Two-dimensional Magnetic Bernstein-Greene-Kruskal Modes

    E-Print Network [OSTI]

    Ng, Chung-Sang

    Electrostatic Structures in Space Plasmas: Properties of Two-dimensional Magnetic Bernstein-Greene theoretical description of some of these structures is the concept of Bernstein-Greene-Kruskal (BGK) modes of their properties, including its energy content, temperature and velocity distribution, and stability. This work

  11. Stability Studies of Two-dimensional Magnetic Bernstein-Greene-Kruskal Modes using PIC

    E-Print Network [OSTI]

    Ng, Chung-Sang

    Stability Studies of Two-dimensional Magnetic Bernstein-Greene-Kruskal Modes using PIC Simulations + + + + + + + - - - - - - - - #12;General Form of Exact Solutions #12;One Particular Solution #12;Solution with very small e #12;PIC simulations using OOPIC Pro ce = 10 pe See http://www.gi.alaska.edu/~chungsangng/bgk/bgk_b10_xyphs.mov #12;PIC

  12. Two-Dimensional Chalcogenide Nanoplates as Tunable Metamaterials via Chemical Intercalation

    E-Print Network [OSTI]

    Cui, Yi

    Following the success of graphene and boron nitride, two- dimensional (2D) layered metal chalcogenides. Here, we explore 2D metal chalcogenides as a potential material platform for plasmonic and photonic include metamaterials with a gain medium,15,16 intermetallics,17 heavily doped semiconductors with carrier

  13. Correlation energy of finite two-dimensional systems: Toward nonempirical and universal modeling

    E-Print Network [OSTI]

    Gross, E.K.U.

    in quasi-2D structures such as semiconductor layers and sur- faces, quantum-Hall systems, graphene gradient approximations, orbital functionals, and hybrid functionals.2 Such efforts for two- dimensional 2D, and various types of quantum dots3 QDs . When using DFT, QDs are most commonly treated using the 2D

  14. Combustion/micropyretic synthesis of atomically thin two-dimensional materials for energy applications

    E-Print Network [OSTI]

    Mukasyan, Alexander

    Combustion/micropyretic synthesis of atomically thin two-dimensional materials for energy unique inexpensive combustion-based approaches have been developed to prepare the nanomaterials. This article specifically aims to be an overview of current trends and as a perspective of combustion synthesis

  15. Stability Analysis of the Immersed Boundary Method for a Two-dimensional Membrane with Bending Rigidity

    E-Print Network [OSTI]

    Huang, Huaxiong

    Stability Analysis of the Immersed Boundary Method for a Two-dimensional Membrane with Bending Rigidity Zhaoxin Gong1 , Huaxiong Huang1,2 and Chuanjing Lu1 Abstract: In this paper, we analyse with bending rigidity. The smoothed version, using a standard regularization technique for the singular force

  16. Insertion of a Two-Dimensional Iron-Chloride Network between Perovskite Blocks. Synthesis and

    E-Print Network [OSTI]

    Spinu, Leonard

    Insertion of a Two-Dimensional Iron-Chloride Network between Perovskite Blocks. Synthesis between the perovskite blocks of a double-layered Dion-Jacobson compound. The product, (FeCl)- LaNb2O7, contains iron coordinated by two apical oxygens from the perovskite layer and four in-plane chlorines

  17. Investigation of transient, two-dimensional coupled heat and moisture flow in soils

    SciTech Connect (OSTI)

    Shen, L.S.W.

    1986-01-01

    A two-dimensional finite difference numerical model has been developed to study coupled heat and moisture flow in the soil surrounding an earth-sheltered construction. The model is based on a mechanistic approach formulated by Milly and developed from the work of Philip and deVries. Using soil temperatures and matric potentials as the dependent variables, the model is capable of simulating unsaturated/saturated flow conditions in heterogeneous soil domains. The model is a fully implicit, integrated finite difference approach based on the Patankar Spalding method. The numerical modeling of the governing heat and moisture equations was validated against a number of analytical and quasi-analytical solutions. An axisymmetric, two-dimensional experiment was then defined to which the numerical model could be compared. The experimental apparatus was composed of a cylinder filled with a dredged Mississippi River sand. A series of one and two dimensional heat and moisture flow experiments were run, using boundary conditions consistent with those that occur in the soil surrounding a building. Soil properties used in the model were either calculated from theoretical models or measured experimentally. Agreement between the model and experiments were good, with an error of 10-15% obtained for the two-dimensional coupled heat and moisture flow experiment.

  18. The stability of a two-dimensional vorticity filament under uniform strain

    E-Print Network [OSTI]

    Wirosoetisno, Djoko

    The stability of a two-dimensional vorticity filament under uniform strain Article Published-dimensional vorticity filament under uniform strain. Journal of Fluid Mechanics, 230 (1). pp. 647-665. ISSN 0022-dimensional vorticity filament under uniform strain By D. G. DRITSCHEL, P.H. HAYNES, M. N. JUCKES? AND T. G. SHEPHERDS

  19. Fractures in heterogeneous two-dimensional systems Antonio Politi1,2,

    E-Print Network [OSTI]

    Politi, Antonio

    Fractures in heterogeneous two-dimensional systems Antonio Politi1,2, * and Maria Zei2,3,4, 1 disorder is used as a testing ground for fracture behavior in heterogeneous materials in strain and different breaking thresholds. We study the strain range where the fracture progressively develops from

  20. BATTRI: A TWO-DIMENSIONAL BATHYMETRY BASED UNSTRUCTURED TRIANGULAR GRID GENERATOR

    E-Print Network [OSTI]

    of Delaunay unstructured triangular grid refinement algorithms, including the recent "off-centers" method Delaunay scheme, called "off-centers" [10], on reducing the number of grid nodes without sacrificingBATTRI: A TWO-DIMENSIONAL BATHYMETRY BASED UNSTRUCTURED TRIANGULAR GRID GENERATOR FOR FINITE

  1. 38 | OPN December 2006 www.osa-opn.org Molding Light in Two-Dimensional

    E-Print Network [OSTI]

    38 | OPN December 2006 www.osa-opn.org Molding Light in Two-Dimensional Photonic Lattices Robert, these approaches may only allow limited flexibility in the light molding and rout- ing that is inherently state selects itself the propagation direction in defect-free periodic struc- tures. The symmetry

  2. Transformation Property of the Caputo Fractional Differential Operator in Two Dimensional Space

    E-Print Network [OSTI]

    Ehab Malkawi

    2013-05-06

    The transformation property of the Caputo fractional derivative operator of a scalar function under rotation in two dimensional space is derived. The study of the transformation property is essential for the formulation of fractional calculus in multi-dimensional space. The inclusion of fractional calculus in the Lagrangian and Hamiltonian dynamics relies on such transformation. An illustrative example is given.

  3. A THz transverse electromagnetic mode two-dimensional interconnect layer incorporating quasi-optics

    E-Print Network [OSTI]

    of transmitting subpicosecond pulses in the transverse electromagnetic TEM mode over arbitrarily long paths near the cutoff fre- quency. Such pulse broadening does not occur for the trans- verse electromagneticA THz transverse electromagnetic mode two-dimensional interconnect layer incorporating quasi

  4. Two dimensional representation of the Dirac equation in Non associative algebra

    E-Print Network [OSTI]

    S. Hamieh; H. Abbas

    2011-04-18

    In this note a simple extension of the complex algebra to higher dimension is proposed. Using the postulated algebra a two dimensional Dirac equation is formulated and its solution is calculated. It is found that there is a sub-algebra where the associative nature can be recovered.

  5. A Two-Dimensional Model of Chemical Vapor Infiltration With Radio Frequency Heating

    E-Print Network [OSTI]

    Economou, Demetre J.

    by a finite element method to study carbon chemical vapor infiltration in a cylindrical carbon preformA Two-Dimensional Model of Chemical Vapor Infiltration With Radio Frequency Heating Vikas Midha studied. The power density distribution in the pre- form evolves in a complex manner as densified regions

  6. PHYSICAL REVIEW E 87, 013106 (2013) Longitudinal viscosity of two-dimensional Yukawa liquids

    E-Print Network [OSTI]

    Goree, John

    2013-01-01

    is obtained for a two-dimensional (2D) liquid using a Green-Kubo method with a molecular dynamics simulation characterize energy dissipation in a fluid. Bulk viscosity is for energy dissipation due to compression, in contrast, is for energy dissipation due to a gradient in the flow velocity. In the latter case, the energy

  7. Fast transport, atom sample splitting and single-atom qubit supply in two-dimensional arrays

    E-Print Network [OSTI]

    Birkl, Gerhard

    Fast transport, atom sample splitting and single-atom qubit supply in two-dimensional arrays architecture for neutral atom quantum information processing, quantum simulation and the manipulation of ultra-cold implemented functions. We introduce piezo-actuator-based transport of atom ensembles over distances of more

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

    E-Print Network [OSTI]

    Pompili, Dario

    Three-dimensional and two-dimensional deployment analysis for underwater acoustic sensor networks q t i c l e i n f o Article history: Received 8 October 2007 Received in revised form 11 February 2008 Accepted 23 July 2008 Available online 7 August 2008 Keywords: Underwater acoustic sensor networks

  9. Integrated digital inverters based on two-dimensional anisotropic ReS? field-effect transistors

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

    Liu, Erfu; Fu, Yajun; Wang, Yaojia; Feng, Yanqing; Liu, Huimei; Wan, Xiangang; Zhou, Wei; Wang, Baigeng; Shao, Lubin; Ho, Ching -Hwa; et al

    2015-05-07

    Semiconducting two-dimensional transition metal dichalcogenides are emerging as top candidates for post-silicon electronics. While most of them exhibit isotropic behaviour, lowering the lattice symmetry could induce anisotropic properties, which are both scientifically interesting and potentially useful. Here we present atomically thin rhenium disulfide (ReS?) flakes with unique distorted 1T structure, which exhibit in-plane anisotropic properties. We fabricated monolayer and few-layer ReS? field-effect transistors, which exhibit competitive performance with large current on/off ratios (~10?) and low subthreshold swings (100 mV per decade). The observed anisotropic ratio along two principle axes reaches 3.1, which is the highest among all known two-dimensional semiconductingmore »materials. Furthermore, we successfully demonstrated an integrated digital inverter with good performance by utilizing two ReS? anisotropic field-effect transistors, suggesting the promising implementation of large-scale two-dimensional logic circuits. Our results underscore the unique properties of two-dimensional semiconducting materials with low crystal symmetry for future electronic applications.« less

  10. ENERGY-PRESERVING AND STABLE APPROXIMATIONS FOR THE TWO-DIMENSIONAL SHALLOW WATER EQUATIONS

    E-Print Network [OSTI]

    ENERGY-PRESERVING AND STABLE APPROXIMATIONS FOR THE TWO-DIMENSIONAL SHALLOW WATER EQUATIONS EITAN water equations 13 5.1. Energy stable schemes 13 5.2. Energy preserving schemes 17 6. Numerical TADMOR AND WEIGANG ZHONG Abstract. We present a systematic development of energy-stable approximations

  11. Supplementary information to "Phonons in two-dimensional soft colloidal crystals"

    E-Print Network [OSTI]

    Schindler, Michael

    Supplementary information to "Phonons in two-dimensional soft colloidal crystals" Ke Chen et al. S1. Characterization of colloidal crystals. Colloidal crystals are characterized by sample lattice structure. Figure S1 of low frequency modes obtained from pristine colloidal crystals exhibit features of plane waves

  12. DOI: 10.1002/anie.201105439 Fabrication of Large-Area Two-Dimensional Colloidal Crystals**

    E-Print Network [OSTI]

    Asher, Sanford A.

    Polymers DOI: 10.1002/anie.201105439 Fabrication of Large-Area Two-Dimensional Colloidal Crystals-dimensional crystalline colloidal arrays (CCAs) have numerous applications, such as photonic crystal materials and sensors to prepare close-packed 2D colloidal crystals by floating and re-deposit- ing colloidal monolayers at the air

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

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Two-dimensional 1,3,5-Tris(4-carboxyphenyl)benzene self-assembly at the 1-phenyloctane-assembly of star-shaped 1,3,5-Tris(4-carboxyphenyl)benzene molecules is investigated. Scanning tunneling microscopy.22 showed that 1,3,5-Tris(4-carboxyphenyl)benzene star-shaped molecules can form two distinc self

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

    E-Print Network [OSTI]

    Lin, Pei-Chun

    Two dimensional thermoelectric platforms for thermocapillary droplet actuation Man-Chi Liu,ac Jin the cooling function relies on the natural conduction and/or convection. A thermoelectric (TE) chip a novel approach utilizing a 5 6 5 array of thermoelectric (TE) chips. The advantage of using TE chips

  15. IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 58, NO. 5, MAY 2010 2757 Multichannel Deconvolution of Seismic Signals

    E-Print Network [OSTI]

    Cohen, Israel

    IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 58, NO. 5, MAY 2010 2757 Multichannel Deconvolution of Seismic Signals Using Statistical MCMC Methods Idan Ram, Israel Cohen, Senior Member, IEEE, and Shalom Raz of two-dimensional (2D) seismic data. Both algorithms are based on a 2D reflectivity prior model, and use

  16. Elastic-Wavefield Seismic Stratigraphy: A New Seismic Imaging Technology

    SciTech Connect (OSTI)

    Bob A. Hardage; Milo M. Backus; Michael V. DeAngelo; Sergey Fomel; Khaled Fouad; Robert J. Graebner; Paul E. Murray; Randy Remington; Diana Sava

    2006-07-31

    The purpose of our research has been to develop and demonstrate a seismic technology that will provide the oil and gas industry a better methodology for understanding reservoir and seal architectures and for improving interpretations of hydrocarbon systems. Our research goal was to expand the valuable science of seismic stratigraphy beyond the constraints of compressional (P-P) seismic data by using all modes (P-P, P-SV, SH-SH, SV-SV, SV-P) of a seismic elastic wavefield to define depositional sequences and facies. Our objective was to demonstrate that one or more modes of an elastic wavefield may image stratal surfaces across some stratigraphic intervals that are not seen by companion wave modes and thus provide different, but equally valid, information regarding depositional sequences and sedimentary facies within that interval. We use the term elastic wavefield stratigraphy to describe the methodology we use to integrate seismic sequences and seismic facies from all modes of an elastic wavefield into a seismic interpretation. We interpreted both onshore and marine multicomponent seismic surveys to select the data examples that we use to document the principles of elastic wavefield stratigraphy. We have also used examples from published papers that illustrate some concepts better than did the multicomponent seismic data that were available for our analysis. In each interpretation study, we used rock physics modeling to explain how and why certain geological conditions caused differences in P and S reflectivities that resulted in P-wave seismic sequences and facies being different from depth-equivalent S-wave sequences and facies across the targets we studied.

  17. Terahertz magneto-optical spectroscopy of a two-dimensional hole gas

    SciTech Connect (OSTI)

    Kamaraju, N.; Pan, W.; Ekenberg, U.; Gvozdi?, D. M.; Boubanga-Tombet, S.; Upadhya, P. C.; Reno, J.; Taylor, A. J.; Prasankumar, R. P.

    2015-01-21

    Two-dimensional hole gases (2DHGs) have attracted recent attention for their unique quantum physics and potential applications in areas including spintronics and quantum computing. However, their properties remain relatively unexplored, motivating the use of different techniques to study them. We then used terahertz magneto-optical spectroscopy to investigate the cyclotron resonance frequency in a high mobility 2DHG, revealing a nonlinear dependence on the applied magnetic field. This is shown to be due to the complex non-parabolic valence band structure of the 2DHG, as verified by multiband Landau level calculations. We also found that impurity scattering dominates cyclotron resonance decay in the 2DHG, in contrast with the dominance of superradiant damping in two-dimensional electron gases. Our results shed light on the properties of 2DHGs, motivating further studies of these unique 2D nanosystems.

  18. Terahertz magneto-optical spectroscopy of a two-dimensional hole gas

    SciTech Connect (OSTI)

    Kamaraju, N. Taylor, A. J.; Prasankumar, R. P.; Pan, W.; Reno, J.; Ekenberg, U.; Gvozdi?, D. M.; Boubanga-Tombet, S.; Upadhya, P. C.

    2015-01-19

    Two-dimensional hole gases (2DHGs) have attracted recent attention for their unique quantum physics and potential applications in areas including spintronics and quantum computing. However, their properties remain relatively unexplored, motivating the use of different techniques to study them. We used terahertz magneto-optical spectroscopy to investigate the cyclotron resonance frequency in a high mobility 2DHG, revealing a nonlinear dependence on the applied magnetic field. This is shown to be due to the complex non-parabolic valence band structure of the 2DHG, as verified by multiband Landau level calculations. We also find that impurity scattering dominates cyclotron resonance decay in the 2DHG, in contrast with the dominance of superradiant damping in two-dimensional electron gases. Our results shed light on the properties of 2DHGs, motivating further studies of these unique 2D nanosystems.

  19. Terahertz magneto-optical spectroscopy of a two-dimensional hole gas

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

    Kamaraju, N.; Pan, W.; Ekenberg, U.; Gvozdi?, D. M.; Boubanga-Tombet, S.; Upadhya, P. C.; Reno, J.; Taylor, A. J.; Prasankumar, R. P.

    2015-01-21

    Two-dimensional hole gases (2DHGs) have attracted recent attention for their unique quantum physics and potential applications in areas including spintronics and quantum computing. However, their properties remain relatively unexplored, motivating the use of different techniques to study them. We then used terahertz magneto-optical spectroscopy to investigate the cyclotron resonance frequency in a high mobility 2DHG, revealing a nonlinear dependence on the applied magnetic field. This is shown to be due to the complex non-parabolic valence band structure of the 2DHG, as verified by multiband Landau level calculations. We also found that impurity scattering dominates cyclotron resonance decay in the 2DHG,more »in contrast with the dominance of superradiant damping in two-dimensional electron gases. Our results shed light on the properties of 2DHGs, motivating further studies of these unique 2D nanosystems.« less

  20. Resonant tunneling device with two-dimensional quantum well emitter and base layers

    DOE Patents [OSTI]

    Simmons, Jerry A. (Sandia Park, NM); Sherwin, Marc E. (Rockville, MD); Drummond, Timothy J. (Tijeras, NM); Weckwerth, Mark V. (Pleasanton, CA)

    1998-01-01

    A double electron layer tunneling device is presented. Electrons tunnel from a two dimensional emitter layer to a two dimensional tunneling layer and continue traveling to a collector at a lower voltage. The emitter layer is interrupted by an isolation etch, a depletion gate, or an ion implant to prevent electrons from traveling from the source along the emitter to the drain. The collector is similarly interrupted by a backgate, an isolation etch, or an ion implant. When the device is used as a transistor, a control gate is added to control the allowed energy states of the emitter layer. The tunnel gate may be recessed to change the operating range of the device and allow for integrated complementary devices. Methods of forming the device are also set forth, utilizing epoxy-bond and stop etch (EBASE), pre-growth implantation of the backgate or post-growth implantation.

  1. Two Dimensional Integration of Ring Cavity Surface Emitting Quantum Cascade Lasers

    SciTech Connect (OSTI)

    Schwarzer, Clemens; Mujagic, Elvis; Zederbauer, Tobias; Detz, Hermann; Andrews, Aaron M.; Schrenk, Werner; Strasser, Gottfried [Institute for Solid State Electronics, Vienna University of Technology, 1040 Vienna (Austria); Yao Yu; Chen Jianxin; Gmachl, Claire [Department of Electrical Engineering, Princeton University, Princeton, NJ 08544 (United States)

    2011-12-26

    The continual improvements over the last fifteen years have made quantum cascade lasers reliable and versatile light sources in the mid infrared and the terahertz spectral regions. In this work we present our latest results regarding the implementation of these light sources for forming broad band emitting two-dimensional laser arrays. A spectral tuning range of 180 cm{sup -1} around the centered wavelength of 8.2 {mu}m could be shown.

  2. Spin-orbit interaction controlled properties of two-dimensional superlattices: Spintronic crystals

    E-Print Network [OSTI]

    Peter Foldi; Viktor Szaszko-Bogar; F. M. Peeters

    2015-03-03

    The band structure of two-dimensional artificial superlattices in the presence of (Rashba-type) spin-orbit interaction (SOI) is presented. The position and shape of the energy bands in these spintronic crystals depend on the geometry as well as the strength of the SOI, which can be tuned by external gate voltages. For finite mesoscopic arrays we show that their conductance properties can be understood from these spin-dependent band diagrams.

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

    SciTech Connect (OSTI)

    Cybart, Shane A. Dynes, R. C.; Wong, T. J.; Cho, E. Y.; Beeman, J. W.; Yung, C. S.; Moeckly, B. H.

    2014-05-05

    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.

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

    E-Print Network [OSTI]

    Georgios Fotopoulos; Valery Serov

    2014-12-01

    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.

  5. Instantons and the fixed point topological charge in the two-dimensional O(3) {sigma} model

    SciTech Connect (OSTI)

    Blatter, M.; Burkhalter, R.; Hasenfratz, P.; Niedermayer, F.

    1996-01-01

    We define a fixed point topological charge for the two-dimensional O(3) lattice {sigma} model which is free of topological defects. We use this operator in combination with the fixed point action to measure the topological susceptibility for a wide range of correlation lengths. The results strongly suggest that it is not a physical quantity in this model. The procedure, however, can be applied to other asymptotically free theories as well. {copyright} {ital 1996 The American Physical Society.}

  6. Magnetohydrodynamic waves in two-dimensional prominences embedded in coronal arcades

    SciTech Connect (OSTI)

    Terradas, J.; Soler, R.; Dķaz, A. J.; Oliver, R.; Ballester, J. L.

    2013-11-20

    Solar prominence models used so far in the analysis of MHD waves in two-dimensional structures are quite elementary. In this work, we calculate numerically magnetohydrostatic models in two-dimensional configurations under the presence of gravity. Our interest is in models that connect the magnetic field to the photosphere and include an overlying arcade. The method used here is based on a relaxation process and requires solving the time-dependent nonlinear ideal MHD equations. Once a prominence model is obtained, we investigate the properties of MHD waves superimposed on the structure. We concentrate on motions purely two-dimensional, neglecting propagation in the ignorable direction. We demonstrate how, by using different numerical tools, we can determine the period of oscillation of stable waves. We find that vertical oscillations, linked to fast MHD waves, are always stable and have periods in the 4-10 minute range. Longitudinal oscillations, related to slow magnetoacoustic-gravity waves, have longer periods in the range of 28-40 minutes. These longitudinal oscillations are strongly influenced by the gravity force and become unstable for short magnetic arcades.

  7. Remarks on the two-dimensional power correction in the soft wall model

    E-Print Network [OSTI]

    Tao Huang; Fen Zuo

    2009-09-15

    We present a direct derivation of the two-point correlation function of the vector current in the soft wall model by using the AdS/CFT dictionary. The resulting correlator is exactly the same as the one previously obtained from dispersion relation with the same spectral function as in this model. The coefficient $C_2$ of the two-dimensional power correction is found to be $C_2=-c/2$ with $c$ the slope of the Regge trajectory, rather than $C_2=-c/3$ derived from the strategy of first quantized string theory. Taking the slope of the $\\rho$ trajectory $c\\approx0.9{GeV}^2$ as input, we then get $C_2\\approx-0.45{GeV}^2$. The gluon condensate is found to be $\\approx0.064{GeV}^4$, which is almost identical to the QCD sum rule estimation. By comparing these two equivalent derivation of the correlator of scalar glueball operator, we demonstrate that the two-dimensional correction can't be eliminated by including the non-leading solution in the bulk-to-boundary propagator, as was done in \\cite{Colangelo2}. In other words, the two-dimensional correction does exist in the scalar glueball case. Also it is manifest by using the dispersion relation that the minus sign of gluon condensate and violation of the low energy theorem are related to the subtraction scheme.

  8. Preliminary results for a two-dimensional simulation of the working process of a Stirling engine

    SciTech Connect (OSTI)

    Makhkamov, K.K.; Ingham, D.B.

    1998-07-01

    Stirling engines have several potential advantages over existing types of engines, in particular they can use renewable energy sources for power production and their performance meets the demands on the environmental security. In order to design Stirling Engines properly, and to put into effect their potential performance, it is important to more accurately mathematically simulate its working process. At present, a series of very important mathematical models are used for describing the working process of Stirling Engines and these are, in general, classified as models of three levels. All the models consider one-dimensional schemes for the engine and assume a uniform fluid velocity, temperature and pressure profiles at each plane of the internal gas circuit of the engine. The use of two-dimensional CFD models can significantly extend the capabilities for the detailed analysis of the complex heat transfer and gas dynamic processes which occur in the internal gas circuit, as well as in the external circuit of the engine. In this paper a two-dimensional simplified frame (no construction walls) calculation scheme for the Stirling Engine has been assumed and the standard {kappa}-{var{underscore}epsilon} turbulence model has been used for the analysis of the engine working process. The results obtained show that the use of two-dimensional CFD models gives the possibility of gaining a much greater insight into the fluid flow and heat transfer processes which occur in Stirling Engines.

  9. Two-dimensional numerical model of underground oil-shale retorting

    SciTech Connect (OSTI)

    Travis, B.J.; Hommert, P.J.; Tyner, C.E.

    1983-01-01

    A two-dimensional numerical model of underground oil shale retorting, which fully couples retorting chemistry with fluid and heat flow, has been developed. The model solves the time-dependent, two-dimensional mass, momentum, and energy balance equations for a nine-component fluid (O/sub 2/, N/sub 2/, H/sub 2/, CO/sub 2/, CO, CH/sub 4/, CH/sub x/, H/sub 2/O, and oil). Water and oil can flow in the liquid and/or vapor phases. Retort chemistry includes kerogen pyrolysis, carbonate decomposition, char reactions, and combustion. Also, detailed modeling of heat flow and chemistry inside shale particles allows large rubble sizes as well as small sizes to be considered. The model is compared to one-dimensional experimental data obtained from Lawrence Livermore National Laboratory. The model can be used to examine the effect of two-dimensional variations in shale grade, rubble size, permeability, porosity, geometry, inflow gas composition, etc. on retorting efficiency and process optimization. A sample calculation is presented.

  10. Surveys

    Broader source: Energy.gov [DOE]

    Surveys can be a useful way to gauge the opinions of your readers and learn more about your website's audiences, but you'll often need approval from the Office of Management and Budget (OMB) to run...

  11. A SIMPLE APPROACH TO HIGH RESOLUTION SEISMIC PROFILING FOR COAL *

    E-Print Network [OSTI]

    A SIMPLE APPROACH TO HIGH RESOLUTION SEISMIC PROFILING FOR COAL * BY A. ZIOLKOWSKI ** and W. E Seismic Profiling for Coal, Geophysical Prospecting 27, 360-393, Seismic exploration techniques which have been developed for oil prospecting contrib- ute a valuable means for surveying coal measures. Since

  12. Staged Hybrid Genetic Search for Seismic Data Imaging

    E-Print Network [OSTI]

    Whitley, Darrell

    . Geological exploration em­ ploys seismic reflection surveys to obtain subsurface im­ ages of geologic bedsStaged Hybrid Genetic Search for Seismic Data Imaging Keith E. Mathias, y L. Darrell Whitley, y Christof Stork yy and Tony Kusuma yy Abstract --- Seismic data interpretation problems are typ­ ically

  13. Relaxation of hot electrons in a degenerate two-dimensional electron system: transition to one-dimensional scattering

    E-Print Network [OSTI]

    Ludwig-Maximilians-Universität, München

    Relaxation of hot electrons in a degenerate two-dimensional electron system: transition to one, 2011) The energy relaxation channels of hot electrons far from thermal equilibrium in a degenerate two-dimensional electron system are investigated in transport experiments in a mesoscopic three- terminal device. We

  14. Data Detection for Two-Dimensional ISI Channels Joseph A. O'Sullivan, Naveen Singla, Yunxiang Wu, Ronald S. Indeck

    E-Print Network [OSTI]

    O'Sullivan, Joseph A.

    1 Data Detection for Two-Dimensional ISI Channels Joseph A. O'Sullivan, Naveen Singla, Yunxiang Wu-mail:{jao, singla, ywu, rsi}@ee.wustl.edu Introduction Two-dimensional (2-D) inter symbol interference (ISI) arises-D ISI channels. The motivation for considering 2-D recording is two fold; firstly, as 1-D recording

  15. A Family of Fourth Order Difference Schemes on Rotated Grid for Two Dimensional ConvectionDiffusion Equation \\Lambda

    E-Print Network [OSTI]

    Zhang, Jun

    A Family of Fourth Order Difference Schemes on Rotated Grid for Two Dimensional Convection a family of fourth order finite difference schemes on the rotated grid for the two dimensional convection values of the convection coefficients. We also compare the fourth order schemes with the nine point

  16. Two-dimensional calculation of eddy currents on external conducting walls induced by low-n external modes

    E-Print Network [OSTI]

    Two-dimensional calculation of eddy currents on external conducting walls induced by low-n external 1997; accepted 8 December 1997 The results of two-dimensional calculations of eddy currents induced on external conducting walls surrounding a tokamak are reported. The computed eddy currents are generated

  17. ccsd-00085042,version1-11Jul2006 A Two-dimensional eddy current model using thin

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ccsd-00085042,version1-11Jul2006 A Two-dimensional eddy current model using thin inductors Youcef a mathematical model for eddy currents in two dimensional geometries where the conductors are thin domains. We Mathematical modelling of eddy current problems often involves multiple conductors with various sizes

  18. Linear temperature dependence of the conductivity in Si two-dimensional electrons near the apparent metal-to-insulator transition

    E-Print Network [OSTI]

    Dobrosavljevic, Vladimir

    Linear temperature dependence of the conductivity in Si two-dimensional electrons near the apparent mobility two-dimensional electron system in Si, near the critical density, nc=0.32 1011 cm-2 , of the apparent metal-to-insulator transition, the conductivity displays a linear temperature T dependence around

  19. Comment on ``Finding finite-time invariant manifolds in two-dimensional velocity fields'' Chaos 10, 99 ,,2000...

    E-Print Network [OSTI]

    Lapeyre, Guillaume

    Comment on ``Finding finite-time invariant manifolds in two-dimensional velocity fields'' Chaos 10 for transport and mixing in periodic and aperi- odic flows. For aperiodic two-dimensional flows, several the hyperbolic point. He further claims that this is generally sufficient to accurately identify the hyper- bolic

  20. Two-Dimensional Reaction Free Energy Surfaces of Catalytic Reaction: Effects of Protein Conformational Dynamics on Enzyme Catalysis

    E-Print Network [OSTI]

    Xie, Xiaoliang Sunney

    Two-Dimensional Reaction Free Energy Surfaces of Catalytic Reaction: Effects of Protein Form: October 23, 2007 We introduce a two-dimensional (2D) multisurface reaction free energy space representing different states of the cycle, which is constructed according to the free energy

  1. On the boundary conditions for EG-methods applied to the two-dimensional wave equation system

    E-Print Network [OSTI]

    On the boundary conditions for EG-methods applied to the two-dimensional wave equation system M Galerkin methods (EG) which are applied for the two-dimensional wave equation system. Di#11;erent known of hyperbolic equations, see, e.g. Grote and Keller [5, 6, 7], En- gquist and Majda [3], Higdon [9], Thompson

  2. Two-dimensional model problem to explain counter-rotating vortex pair formation in a transverse jet

    E-Print Network [OSTI]

    Mahesh, Krishnan

    Two-dimensional model problem to explain counter-rotating vortex pair formation in a transverse jet A two-dimensional model problem is used to study the evolution of the cross section of a transverse jet and the counter-rotating vortex pair CVP . The solution to the model problem shows deformation of the jet similar

  3. Lake Geneva Holocene delta seismic stratigraphy S11 High-resolution seismic stratigraphy of an Holocene lacustrine delta in

    E-Print Network [OSTI]

    Gilli, Adrian

    Lake Geneva Holocene delta seismic stratigraphy S11 High-resolution seismic stratigraphy stratigraphy, slope instability, gas blanking, 3-D model. Mots-clés: delta lacustre, Lac Léman, Holocčne, stratigraphie sismique, instabilité de pente, zone sourde, modčle 3-D. ABSTRACT A high-resolution seismic survey

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

    SciTech Connect (OSTI)

    Goldberg, L.F.

    1990-08-01

    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.

  5. Use and abuse of seismic data in reservoir characterisation J. Hesthammera,*, M. Landrb,1

    E-Print Network [OSTI]

    Fossen, Haakon

    . This is especially a problem when interpreting seismic attribute maps. Such maps are widely used tools during development plans for oil ®elds. A recent interpretation of seismic attribute maps from a seismic survey; Gullveig 1. Introduction Today, most thorough seismic interpretations will be based on an integrated use

  6. Current Statistics for Quantum Transport through Two-Dimensional Open Chaotic Billiards

    E-Print Network [OSTI]

    Alexander I. Saichev; Hiromu Ishio; Almas F. Sadreev; Karl-Fredrik Berggren

    2001-11-03

    The probability current statistics of two-dimensional open chaotic ballistic billiards is studied both analytically and numerically. Assuming that the real and imaginary parts of the scattering wave function are both random Gaussian fields, we find a universal distribution function for the probability current. In by-passing we recover previous analytic forms for wave function statistics. The expressions bridge the entire region from GOE to GUE type statistics. Our analytic expressions are verified numerically by explicit quantum-mechanical calculations of transport through a Bunimovich billiard.

  7. Thermal conductivity of configurable two-dimensional carbon nanotube architecture and strain modulation

    SciTech Connect (OSTI)

    Zhan, H. F.; Bell, J. M.; Gu, Y. T., E-mail: yuantong.gu@qut.edu.au [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, 2 George St., Brisbane, Queensland 4000 (Australia); Zhang, G. [Institute of High Performance Computing, Agency for Science, Technology and Research, 1 Fusionopolis Way, Singapore 138632 (Singapore)

    2014-10-13

    We reported the thermal conductivity of the two-dimensional carbon nanotube (CNT)-based architecture, which can be constructed through welding of single-wall CNTs by electron beam. Using large-scale nonequilibrium molecular dynamics simulations, the thermal conductivity is found to vary with different junction types due to their different phonon scatterings at the junction. The strong length and strain dependence of the thermal conductivity suggests an effective avenue to tune the thermal transport properties of the CNT-based architecture, benefiting the design of nanoscale thermal rectifiers or phonon engineering.

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

    SciTech Connect (OSTI)

    Sunada, Satoshi Adachi, Masaaki; Fukushima, Takehiro; Shinohara, Susumu; Arai, Kenichi; Harayama, Takahisa

    2014-06-16

    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.

  9. Characterization of metal contacts for two-dimensional MoS{sub 2} nanoflakes

    SciTech Connect (OSTI)

    Walia, Sumeet, E-mail: madhu.bhaskaran@rmit.edu.au, E-mail: kourosh.kalantar@rmit.edu.au, E-mail: sumeet.walia@rmit.edu.au; Balendhran, Sivacarendran; Sriram, Sharath; Bhaskaran, Madhu, E-mail: madhu.bhaskaran@rmit.edu.au, E-mail: kourosh.kalantar@rmit.edu.au, E-mail: sumeet.walia@rmit.edu.au [Functional Materials and Microsystems Research Group, RMIT University, Melbourne, Victoria 3000 (Australia) [Functional Materials and Microsystems Research Group, RMIT University, Melbourne, Victoria 3000 (Australia); School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria 3000 (Australia); Wang, Yichao; Ab Kadir, Rosmalini; Sabirin Zoolfakar, Ahmad; Atkin, Paul; Zhen Ou, Jian; Kalantar-zadeh, Kourosh, E-mail: madhu.bhaskaran@rmit.edu.au, E-mail: kourosh.kalantar@rmit.edu.au, E-mail: sumeet.walia@rmit.edu.au [School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria 3000 (Australia)] [School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria 3000 (Australia)

    2013-12-02

    While layered materials are increasingly investigated for their potential in nanoelectronics, their functionality and efficiency depend on charge injection into the materials via metallic contacts. This work explores the characteristics of different metals (aluminium, tungsten, gold, and platinum) deposited on to nanostructured thin films made of two-dimensional (2D) MoS{sub 2} flakes. Metals are chosen based on their work functions relative to the electron affinity of MoS{sub 2}. It is observed, and analytically verified that lower work functions of the contact metals lead to smaller Schottky barrier heights and consequently higher charge carrier injection through the contacts.

  10. On the Classical Solutions of Two Dimensional Inviscid Rotating Shallow Water System

    E-Print Network [OSTI]

    Bin Cheng; Chunjing Xie

    2009-07-01

    We prove global existence and asymptotic behavior of classical solutions for two dimensional inviscid Rotating Shallow Water system with small initial data subject to the zero-relative-vorticity constraint. One of the key steps is a reformulation of the problem into a symmetric quasilinear Klein-Gordon system, for which the global existence of classical solutions is then proved with combination of the vector field approach and the normal forms. We also probe the case of general initial data and reveal a lower bound for the lifespan that is almost inversely proportional to the size of the initial relative vorticity.

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

    E-Print Network [OSTI]

    Soylu, A; Boztosun, I

    2006-01-01

    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.

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

    E-Print Network [OSTI]

    A. Soylu; O. Bayrak; I. Boztosun

    2007-03-13

    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.

  13. Structure, Bose-Einstein condensation, and superfluidity of two-dimensional confined dipolar assemblies

    SciTech Connect (OSTI)

    Jain, Piyush; Cinti, Fabio; Boninsegni, Massimo [Department of Physics, University of Alberta, Edmonton, Alberta (Canada)

    2011-07-01

    Low-temperature properties of harmonically confined two-dimensional assemblies of dipolar bosons are systematically investigated by Monte Carlo simulations. Calculations carried out for different numbers of particles and strengths of the confining potential yield evidence of a quantum phase transition from a superfluid to a crystal-like phase, consistently with what is observed in the homogeneous system. It is found that the crystal phase nucleates in the center of the trap, as the density increases. Bose-Einstein condensation vanishes at T=0 upon entering the crystalline phase, concurrently with the disappearance of the superfluid response.

  14. Weakly interacting two-dimensional system of dipoles: Limitations of the mean-field theory

    SciTech Connect (OSTI)

    Astrakharchik, G. E.; Boronat, J.; Casulleras, J.; Kurbakov, I. L.; Lozovik, Yu. E.

    2007-06-15

    We consider a homogeneous two-dimensional Bose gas with repulsive dipole-dipole interactions. The ground-state equation of state, calculated using the diffusion Monte Carlo method, shows quantitative differences from the predictions of the commonly used Gross-Pitaevskii mean-field theory. The static structure factor, pair distribution function, and condensate fraction are calculated in a wide range of the gas parameter. Differences from mean-field theory are reflected in the frequency of the lowest ''breathing'' mode for harmonically trapped systems.

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

    E-Print Network [OSTI]

    Kondagunta, Veeraraghava Gopal

    1993-01-01

    and continuity[7]. The model is still two-dimensional and the actual three-dimension- al cross-sectional shape of the fiber bundles was not considered. The fiber undulation model could analyze the knee behavior in plain-weave composites. Ishikawa and Chou [7... is discussed. 23 III. 2 Micromechanics model for calculating fiber tow properties One of the most basic problems in the analysis of the behavior of composite materials is the prediction of effective or average macroscopic properties in terms...

  16. Vacuum Instability in Chern-Simons Theory, Null Vectors and Two-Dimensional Logarithmic Operators

    E-Print Network [OSTI]

    Ian I. Kogan; Alex Lewis

    1998-03-13

    A new relation between two-dimensional conformal field theories and three-dimensional topologically massive gauge theories is found, where the dynamical nature of the 3d theory is ultimately important. It is shown that the those primary states in CFT which have non-unitary descendants correspond in the 3d theory to supercritical charges and cause vacuum instability. It is also shown that logarithmic operators separating the unitary sector from a non-unitary one correspond to an exact zero energy ground state in which case the 3d Hamiltonian naturally has a Jordan structure.

  17. One- and two-dimensional nuclear magnetic resonance spectroscopy with a diamond quantum sensor

    E-Print Network [OSTI]

    J. M. Boss; K. Chang; J. Armijo; K. Cujia; T. Rosskopf; J. R. Maze; C. L. Degen

    2015-12-10

    We report on Fourier spectroscopy experiments performed with near-surface nitrogen-vacancy centers in a diamond chip. By detecting the free precession of nuclear spins rather than applying a multipulse quantum sensing protocol, we are able to unambiguously identify the NMR species devoid of harmonics. We further show that by engineering different Hamiltonians during free precession, the hyperfine coupling parameters as well as the nuclear Larmor frequency can be selectively measured with high precision (here 5 digits). The protocols can be combined to demonstrate two-dimensional Fourier spectroscopy. The technique will be useful for mapping nuclear coordinates in molecules en route to imaging their atomic structure.

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

    E-Print Network [OSTI]

    Miki, Hiroshi; Vinet, Luc; Zhedanov, Alexei

    2012-01-01

    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.

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

    SciTech Connect (OSTI)

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

    2012-05-07

    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.

  20. Observations of indirect exciton trapping in one- and two-dimensional magnetic lattices

    E-Print Network [OSTI]

    Ahmed M. Abdelrahman; Byoung S. Ham

    2012-02-23

    A simple method to create and control magnetic potentials onto coupled quantum wells is demonstrated for indirect-exciton magnetic confinement. Localized inhomogeneous magnetic potentials with periodically distributed local minima and maxima, known as magnetic lattices, are projected into the plane of the coupled quantum wells and used for the spatially distributed two-dimensional indirect-exciton trapping, in which case localized indirect-excitons are observed. The indirect-exciton trapping mechanism is examined by controlling external magnetic field bias resulting in a shift of the localized excitonic lattice.

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

    E-Print Network [OSTI]

    Hiroshi Miki; Satoshi Tsujimoto; Luc Vinet; Alexei Zhedanov

    2012-03-12

    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.

  2. Greybody Factors of Massive Charged Fermionic Fields in a Charged Two-Dimensional Dilatonic Black Hole

    E-Print Network [OSTI]

    Ramon Becar; P. A. Gonzalez; Joel Saavedra; Yerko Vasquez

    2014-12-19

    We study massive charged fermionic perturbations in the background of a charged two-dimensional dilatonic black hole, and we solve the Dirac equation analytically. Then, we compute the reflection and transmission coefficients and the absorption cross section for massive charged fermionic fields, and we show that the absorption cross section vanishes at the low and high frequency limits. However, there is a range of frequencies where the absorption cross section is not null. Furthermore, we study the effect of the mass and electric charge of the fermionic field over the absorption cross section.

  3. Interface Tensions and Perfect Wetting in the Two-Dimensional Seven-State Potts Model

    E-Print Network [OSTI]

    B. Grossmann; Sourendu Gupta

    1993-10-25

    We present a numerical determination of the order-disorder interface tension, \\sod, for the two-dimensional seven-state Potts model. We find $\\sod=0.0114\\pm0.0012$, in good agreement with expectations based on the conjecture of perfect wetting. We take into account systematic effects on the technique of our choice: the histogram method. Our measurements are performed on rectangular lattices, so that the histograms contain identifiable plateaus. The lattice sizes are chosen to be large compared to the physical correlation length. Capillary wave corrections are applied to our measurements on finite systems.

  4. Reflection Survey At Under Steamboat Springs Area (Warpinski...

    Open Energy Info (EERE)

    not indicated DOE-funding Unknown Notes This project consisted of (1) a 3-D surface seismic survey conducted in the fall of 2000, (2) a micro-seismic survey run from November...

  5. Ground Gravity Survey At Under Steamboat Springs Area (Warpinski...

    Open Energy Info (EERE)

    useful DOE-funding Unknown Notes This project consisted of (1) a 3-D surface seismic survey conducted in the fall of 2000, (2) a micro-seismic survey run from November...

  6. Hanford quarterly seismic monitoring report 96C

    SciTech Connect (OSTI)

    Reidel, S.P.

    1996-09-24

    Seismic monitoring at the Hanford Site was established in 1969 by the United States Geological Survey (USGS) under a contract with the U.S. Atomic Energy Commission. In 1975 the University of Washington assumed responsibility for and expanded the network. In 1979 the Basalt Waste Isolation Program (BWIP) became responsible for collecting seismic data for the site as part of site characterization. Rockwell International Operations followed by Westinghouse Hanford Company (WHC), Geosciences Group, operated the local network and were the contract technical advisors for the Eastern Washington Regional Network operated by the University of Washington. Funding ended for BWIP in December 1988. Seismic Monitoring and the University of Washington contract was then transferred WHC`s Environmental Division. Seismic Monitoring is currently assigned to WHC`s Hanford Technical Services (HTS), part of the Environmental Division. The Seismic Monitoring Analysis and Repair Team (SMART) operates, maintains, and analyzes data from the Hanford Seismic Network (HSN), extending the site historical seismic database and fulfilling U.S. Department of Energy, Richland Operations Office requirements and orders. The Seismic Monitoring Analysis and Repair Team also maintains the Eastern Washington Regional Network (EWRN). The University of Washington uses the data from the EWRN and other seismic networks in the Northwest to provide the SMART with necessary regional input for the seismic hazards analysis at the Hanford Site.

  7. Effective field theory and integrability in two-dimensional Mott transition

    SciTech Connect (OSTI)

    Bottesi, Federico L.; Zemba, Guillermo R.

    2011-08-15

    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.

  8. Peak picking and the assessment of separation performance in two-dimensional high performance liquid chromatography

    SciTech Connect (OSTI)

    Guiochon, Georges A; Shalliker, R. Andrew

    2010-01-01

    An algorithm was developed for 2DHPLC that automated the process of peak recognition, measuring their retention times, and then subsequently plotting the information in a two-dimensional retention plane. Following the recognition of peaks, the software then performed a series of statistical assessments of the separation performance, measuring for example, correlation between dimensions, peak capacity and the percentage of usage of the separation space. Peak recognition was achieved by interpreting the first and second derivatives of each respective one-dimensional chromatogram to determine the 1D retention times of each solute and then compiling these retention times for each respective fraction 'cut'. Due to the nature of comprehensive 2DHPLC adjacent cut fractions may contain peaks common to more than one cut fraction. The algorithm determined which components were common in adjacent cuts and subsequently calculated the peak maximum profile by interpolating the space between adjacent peaks. This algorithm was applied to the analysis of a two-dimensional separation of an apple flesh extract separated in a first dimension comprising a cyano stationary phase and an aqueous/THF mobile phase as the first dimension and a second dimension comprising C18-Hydro with an aqueous/MeOH mobile phase. A total of 187 peaks were detected.

  9. Confinement effects of magnetic field on two-dimensional hydrogen atom in plasmas

    SciTech Connect (OSTI)

    Bahar, M. K.; Soylu, A.

    2015-05-15

    In this study, for the first time, the Schrödinger equation with more general exponential cosine screened Coulomb (MGECSC) potential is solved numerically in the presence and in the absence of an external magnetic field within two-dimensional formalism using the asymptotic iteration method. The MGECSC potential includes four different potential forms when considering different sets of the parameters in the potential. The plasma screening effects in the weak and strong magnetic field regimes as well as the confinement effects of magnetic field on the two-dimensional hydrogen atom in Debye and quantum plasmas are investigated by solving the corresponding equations. It is found that applying a uniform magnetic field on the hydrogen atom embedded in a plasma leads to change in the profile of the total interaction potential. Thus, confinement effects of magnetic field on hydrogen atom embedded in Debye and quantum plasmas modeled by a MGECSC potential lead to shift bound state energies. This effect would be important to isolate the plasma from the external environment in the experimental applications of plasma physics.

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

    SciTech Connect (OSTI)

    Cahoon, James Francis

    2008-12-16

    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.

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

    SciTech Connect (OSTI)

    Lu, J.; Bitter, M.; Hill, K. W.; Delgado-Aparicio, L. F.; Efthimion, P. C.; Pablant, N. A.; Beiersdorfer, P.; Caughey, T. A.; Brunner, J.

    2014-11-15

    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.

  12. Two-dimensional numerical simulation of boron diffusion for pyramidally textured silicon

    SciTech Connect (OSTI)

    Ma, Fa-Jun Duttagupta, Shubham; Shetty, Kishan Devappa; Meng, Lei; Hoex, Bram; Peters, Ian Marius; Samudra, Ganesh S.

    2014-11-14

    Multidimensional numerical simulation of boron diffusion is of great relevance for the improvement of industrial n-type crystalline silicon wafer solar cells. However, surface passivation of boron diffused area is typically studied in one dimension on planar lifetime samples. This approach neglects the effects of the solar cell pyramidal texture on the boron doping process and resulting doping profile. In this work, we present a theoretical study using a two-dimensional surface morphology for pyramidally textured samples. The boron diffusivity and segregation coefficient between oxide and silicon in simulation are determined by reproducing measured one-dimensional boron depth profiles prepared using different boron diffusion recipes on planar samples. The established parameters are subsequently used to simulate the boron diffusion process on textured samples. The simulated junction depth is found to agree quantitatively well with electron beam induced current measurements. Finally, chemical passivation on planar and textured samples is compared in device simulation. Particularly, a two-dimensional approach is adopted for textured samples to evaluate chemical passivation. The intrinsic emitter saturation current density, which is only related to Auger and radiative recombination, is also simulated for both planar and textured samples. The differences between planar and textured samples are discussed.

  13. Hexatic phase and cluster crystals of two-dimensional GEM4 spheres

    E-Print Network [OSTI]

    Santi Prestipino; Franz Saija

    2014-11-17

    Two-dimensional crystals of classical particles are very peculiar in that melting may occur in two steps, in a continuous fashion, via an intermediate hexatic fluid phase exhibiting quasi-long-range orientational order. On the other hand, three-dimensional spheres repelling each other through a fast-decaying bounded potential of generalized-exponential shape (GEM4 potential) can undergo freezing into cluster crystals, allowing for more that one particle per lattice site. We hereby study the combined effect of low spatial dimensionality and extreme potential softness, by investigating the phase behavior of the two-dimensional (2D) GEM4 system. Using a combination of density-functional theory and numerical free-energy calculations, we show that the 2D GEM4 system displays one ordinary and several cluster triangular-crystal phases, and that only the ordinary crystal first melts into a hexatic phase. Upon heating, the difference between the various cluster crystals fades away, eventually leaving a single undifferentiated cluster phase with a pressure-modulated site occupancy.

  14. Detector-Response Correction of Two-Dimensional ? -Ray Spectra from Neutron Capture

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

    Rusev, G.; Jandel, M.; Arnold, C. W.; Bredeweg, T. A.; Couture, A.; Mosby, S. M.; Ullmann, J. L.

    2015-05-28

    The neutron-capture reaction produces a large variety of ?-ray cascades with different ?-ray multiplicities. A measured spectral distribution of these cascades for each ?-ray multiplicity is of importance to applications and studies of ?-ray statistical properties. The DANCE array, a 4? ball of 160 BaF2 detectors, is an ideal tool for measurement of neutron-capture ?-rays. The high granularity of DANCE enables measurements of high-multiplicity ?-ray cascades. The measured two-dimensional spectra (?-ray energy, ?-ray multiplicity) have to be corrected for the DANCE detector response in order to compare them with predictions of the statistical model or use them in applications. Themore »detector-response correction problem becomes more difficult for a 4? detection system than for a single detector. A trial and error approach and an iterative decomposition of ?-ray multiplets, have been successfully applied to the detector-response correction. Applications of the decomposition methods are discussed for two-dimensional ?-ray spectra measured at DANCE from ?-ray sources and from the 10B(n, ?) and 113Cd(n, ?) reactions.« less

  15. Solutions of Two Dimensional Viscous Accretion and Winds In Kerr Black Hole Geometry

    E-Print Network [OSTI]

    S. K. Chakrabarti

    1996-11-04

    We extend our previous studies of shock waves and shock-free solutions in thin accretion and winds in pseudo-Newtonian geometry to the case when the flow is ``two-dimensional'' and around a ``Kerr black hole''. We present equations for fully general relativistic viscous transonic flows and classify the parameter space according to whether or not shocks form in an inviscid flow. We discuss the behaviors of shear, angular momentum distribution, heating and cooling in viscous flows. We obtain a very significant result: we find that in weak viscosity limit the presence of the standing shock waves is more generic in the sense that flows away from the equatorial plane can produce shock waves in a wider range of parameter space. Similar conclusion also holds when the angular momentum of the black hole is increased. Generally, our conclusions regarding the shape of the shock waves are found to agree with results of the existing numerical simulations of the two dimensional accretion in Schwarzschild geometry. In a strong viscosity limit, the shocks may be located farther out or disappear completely as in the pseudo-Newtonian geometry.

  16. Particle dynamics in two-dimensional random energy landscapes - experiments and simulations

    E-Print Network [OSTI]

    Florian Evers; Christoph Zunke; Richard D. L. Hanes; Joerg Bewerunge; Imad Ladadwa; Andreas Heuer; Stefan U. Egelhaaf

    2013-06-13

    The dynamics of individual colloidal particles in random potential energy landscapes were investigated experimentally and by Monte Carlo simulations. The value of the potential at each point in the two-dimensional energy landscape follows a Gaussian distribution. The width of the distribution, and hence the degree of roughness of the energy landscape, was varied and its effect on the particle dynamics studied. This situation represents an example of Brownian dynamics in the presence of disorder. In the experiments, the energy landscapes were generated optically using a holographic set-up with a spatial light modulator, and the particle trajectories were followed by video microscopy. The dynamics are characterized using, e.g., the time-dependent diffusion coefficient, the mean squared displacement, the van Hove function and the non-Gaussian parameter. In both, experiments and simulations, the dynamics are initially diffusive, show an extended sub-diffusive regime at intermediate times before diffusive motion is recovered at very long times. The dependence of the long-time diffusion coefficient on the width of the Gaussian distribution agrees with theoretical predictions. Compared to the dynamics in a one-dimensional potential energy landscape, the localization at intermediate times is weaker and the diffusive regime at long times reached earlier, which is due to the possibility to avoid local maxima in two-dimensional energy landscapes.

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

    SciTech Connect (OSTI)

    Abedinpour, Saeed H.; Asgari, Reza; Tanatar, B.; Polini, Marco

    2014-01-15

    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.

  18. Asymmetric Two-dimensional Magnetic Lattices for Ultracold Atoms Trapping and Confinement

    E-Print Network [OSTI]

    A. Abdelrahman; P. Hannaford M. Vasiliev; K. Alameh

    2009-10-27

    A new method to implement an asymmetrical two-dimensional magnetic lattice is proposed. The asymmetrical two-dimensional magnetic lattice can be created by periodically distributing magnetic minima across the surface of magnetic thin film where the periodicity can be achieved by milling $n\\times n$ square holes on the surface of the film. The quantum device is proposed for trapping and confining ultracold atoms and quantum degenerate gases prepared in the low magnetic field seeking-state at low temperature, such as the Bose-Einstein Condensate (BEC) and ultracold fermions. We present detailed analysis of the analytical expressions and the numerical simulation procedure used to calculate the external magnetic field. We also, describe the magnetic band gap structure exhibited by the asymmetric effect of the magnetic minima and show some of the possible application. We analyze the effect of changing the characteristic parameters of the magnetic lattice, such as the separating periodicity length and the hole size along with the applications of the external magnetic bias fields to maintain and allocate a suitable non-zero magnetic local minima at effective $z$-distance above the thin film surface. Suitable values are shown which keep the trapped ultracold atoms away from the thermal Majorana spin-flip and the surface Casimir-Polder effect.

  19. P-WAVE TIME-LAPSE SEISMIC DATA INTERPRETATION AT RULISON FIELD, PICEANCE BASIN, COLORADO

    E-Print Network [OSTI]

    P-WAVE TIME-LAPSE SEISMIC DATA INTERPRETATION AT RULISON FIELD, PICEANCE BASIN, COLORADO by Donald-lapse seismic surveys, shot by the Reservoir Characterization Project in the fall of 2003 and 2004, at Rulison seismic can monitor tight gas reservoirs, to a limited extent, over a short period of time. Repeat surveys

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

    E-Print Network [OSTI]

    Rothrock, Ray Alan

    1978-01-01

    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 ...

  1. Volume 80A, number 4 PHYSICSLETTERS 8 December 1980 FEIGENBAUM'S RATIOS OF TWO-DIMENSIONAL AREA PRESERVING MAPS

    E-Print Network [OSTI]

    Derrida, Bernard

    Volume 80A, number 4 PHYSICSLETTERS 8 December 1980 FEIGENBAUM'S RATIOS OF TWO-DIMENSIONAL AREA preserv- ing case [10] 217 #12;Volume 80A, number 4 PHYSICS LETTERS 8 December 1980 G(x,y) = (1 -//x 2 +y

  2. Structure and phase behavior of a two-dimensional system with core-softened and long-range repulsive interactions 

    E-Print Network [OSTI]

    Camp, Philip J.

    2003-01-01

    The structure and phase behavior of a two-dimensional system with purely repulsive core-softened and long-range interactions are studied using Monte Carlo computer simulations. The pair interactions are of the form, u(r)= ...

  3. Accurate two-dimensional IMRT verification using a back-projection EPID dosimetry method

    SciTech Connect (OSTI)

    Wendling, Markus; Louwe, Robert J.W.; McDermott, Leah N.; Sonke, Jan-Jakob; Herk, Marcel van; Mijnheer, Ben J. [Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Department of Radiation Oncology, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands)

    2006-02-15

    The use of electronic portal imaging devices (EPIDs) is a promising method for the dosimetric verification of external beam, megavoltage radiation therapy--both pretreatment and in vivo. In this study, a previously developed EPID back-projection algorithm was modified for IMRT techniques and applied to an amorphous silicon EPID. By using this back-projection algorithm, two-dimensional dose distributions inside a phantom or patient are reconstructed from portal images. The model requires the primary dose component at the position of the EPID. A parametrized description of the lateral scatter within the imager was obtained from measurements with an ionization chamber in a miniphantom. In addition to point dose measurements on the central axis of square fields of different size, we also used dose profiles of those fields as reference input data for our model. This yielded a better description of the lateral scatter within the EPID, which resulted in a higher accuracy in the back-projected, two-dimensional dose distributions. The accuracy of our approach was tested for pretreatment verification of a five-field IMRT plan for the treatment of prostate cancer. Each field had between six and eight segments and was evaluated by comparing the back-projected, two-dimensional EPID dose distribution with a film measurement inside a homogeneous slab phantom. For this purpose, the {gamma}-evaluation method was used with a dose-difference criterion of 2% of dose maximum and a distance-to-agreement criterion of 2 mm. Excellent agreement was found between EPID and film measurements for each field, both in the central part of the beam and in the penumbra and low-dose regions. It can be concluded that our modified algorithm is able to accurately predict the dose in the midplane of a homogeneous slab phantom. For pretreatment IMRT plan verification, EPID dosimetry is a reliable and potentially fast tool to check the absolute dose in two dimensions inside a phantom for individual IMRT fields. Film measurements inside a phantom can therefore be replaced by EPID measurements.

  4. Advanced Seismic While Drilling System

    SciTech Connect (OSTI)

    Robert Radtke; John Fontenot; David Glowka; Robert Stokes; Jeffery Sutherland; Ron Evans; Jim Musser

    2008-06-30

    A breakthrough has been discovered for controlling seismic sources to generate selectable low frequencies. Conventional seismic sources, including sparkers, rotary mechanical, hydraulic, air guns, and explosives, by their very nature produce high-frequencies. This is counter to the need for long signal transmission through rock. The patent pending SeismicPULSER{trademark} methodology has been developed for controlling otherwise high-frequency seismic sources to generate selectable low-frequency peak spectra applicable to many seismic applications. Specifically, we have demonstrated the application of a low-frequency sparker source which can be incorporated into a drill bit for Drill Bit Seismic While Drilling (SWD). To create the methodology of a controllable low-frequency sparker seismic source, it was necessary to learn how to maximize sparker efficiencies to couple to, and transmit through, rock with the study of sparker designs and mechanisms for (a) coupling the sparker-generated gas bubble expansion and contraction to the rock, (b) the effects of fluid properties and dynamics, (c) linear and non-linear acoustics, and (d) imparted force directionality. After extensive seismic modeling, the design of high-efficiency sparkers, laboratory high frequency sparker testing, and field tests were performed at the University of Texas Devine seismic test site. The conclusion of the field test was that extremely high power levels would be required to have the range required for deep, 15,000+ ft, high-temperature, high-pressure (HTHP) wells. Thereafter, more modeling and laboratory testing led to the discovery of a method to control a sparker that could generate low frequencies required for deep wells. The low frequency sparker was successfully tested at the Department of Energy Rocky Mountain Oilfield Test Center (DOE RMOTC) field test site in Casper, Wyoming. An 8-in diameter by 26-ft long SeismicPULSER{trademark} drill string tool was designed and manufactured by TII. An APS Turbine Alternator powered the SeismicPULSER{trademark} to produce two Hz frequency peak signals repeated every 20 seconds. Since the ION Geophysical, Inc. (ION) seismic survey surface recording system was designed to detect a minimum downhole signal of three Hz, successful performance was confirmed with a 5.3 Hz recording with the pumps running. The two Hz signal generated by the sparker was modulated with the 3.3 Hz signal produced by the mud pumps to create an intense 5.3 Hz peak frequency signal. The low frequency sparker source is ultimately capable of generating selectable peak frequencies of 1 to 40 Hz with high-frequency spectra content to 10 kHz. The lower frequencies and, perhaps, low-frequency sweeps, are needed to achieve sufficient range and resolution for realtime imaging in deep (15,000 ft+), high-temperature (150 C) wells for (a) geosteering, (b) accurate seismic hole depth, (c) accurate pore pressure determinations ahead of the bit, (d) near wellbore diagnostics with a downhole receiver and wired drill pipe, and (e) reservoir model verification. Furthermore, the pressure of the sparker bubble will disintegrate rock resulting in an increased overall rates of penetration. Other applications for the SeismicPULSER{trademark} technology are to deploy a low-frequency source for greater range on a wireline for Reverse Vertical Seismic Profiling (RVSP) and Cross-Well Tomography. Commercialization of the technology is being undertaken by first contacting stakeholders to define the value proposition for rig site services utilizing SeismicPULSER{trademark} technologies. Stakeholders include national oil companies, independent oil companies, independents, service companies, and commercial investors. Service companies will introduce a new Drill Bit SWD service for deep HTHP wells. Collaboration will be encouraged between stakeholders in the form of joint industry projects to develop prototype tools and initial field trials. No barriers have been identified for developing, utilizing, and exploiting the low-frequency SeismicPULSER{trademark} source in a

  5. Spectral evolution of two-dimensional kinetic plasma turbulence in the wavenumber-frequency domain

    SciTech Connect (OSTI)

    Comi?el, H.; Institute for Space Sciences, Atomi?tilor 409, P.O. Box MG-23, Bucharest-M?gurele RO-077125 ; Verscharen, D.; Narita, Y.; Motschmann, U.; Deutsches Zentrum für Luft- und Raumfahrt, Institut für Planetenforschung, Rutherfordstr. 2, D-12489 Berlin

    2013-09-15

    We present a method for studying the evolution of plasma turbulence by tracking dispersion relations in the energy spectrum in the wavenumber-frequency domain. We apply hybrid plasma simulations in a simplified two-dimensional geometry to demonstrate our method and its applicability to plasma turbulence in the ion kinetic regime. We identify four dispersion relations: ion-Bernstein waves, oblique whistler waves, oblique Alfvén/ion-cyclotron waves, and a zero-frequency mode. The energy partition and frequency broadening are evaluated for these modes. The method allows us to determine the evolution of decaying plasma turbulence in our restricted geometry and shows that it cascades along the dispersion relations during the early phase with an increasing broadening around the dispersion relations.

  6. Device for two-dimensional gas-phase separation and characterization of ion mixtures

    DOE Patents [OSTI]

    Tang, Keqi (Richland, WA); Shvartsburg, Alexandre A. (Richland, WA); Smith, Richard D. (Richland, WA)

    2006-12-12

    The present invention relates to a device for separation and characterization of gas-phase ions. The device incorporates an ion source, a field asymmetric waveform ion mobility spectrometry (FAIMS) analyzer, an ion mobility spectrometry (IMS) drift tube, and an ion detector. In one aspect of the invention, FAIMS operating voltages are electrically floated on top of the IMS drift voltage. In the other aspect, the FAIMS/IMS interface is implemented employing an electrodynamic ion funnel, including in particular an hourglass ion funnel. The present invention improves the efficiency (peak capacity) and sensitivity of gas-phase separations; the online FAIMS/IMS coupling creates a fundamentally novel two-dimensional gas-phase separation technology with high peak capacity, specificity, and exceptional throughput.

  7. Orientation, Flow, and Clogging in a Two-Dimensional Hopper: Ellipses vs. Disks

    E-Print Network [OSTI]

    Junyao Tang; Robert P. Behringer

    2015-10-29

    Two-dimensional (2D) hopper flow of disks has been extensively studied. Here, we investigate hopper flow of ellipses with aspect ratio $\\alpha = 2$, and we contrast that behavior to the flow of disks. We use a quasi-2D hopper containing photoelastic particles to obtain stress/force information. We simultaneously measure the particle motion and stress. We determine several properties, including discharge rates, jamming probabilities, and the number of particles in clogging arches. For both particle types, the size of the opening, $D$, relative to the size of particles, $\\ell$ is an important dimensionless measure. The orientation of the ellipses plays an important role in flow rheology and clogging. The alignment of contacting ellipses enhances the probability of forming stable arches. This study offers insight for applications involving the flow of granular materials consisting of ellipsoidal shapes, and possibly other non-spherical shapes.

  8. Entropy and Kinetics of Point-Defects in Two-Dimensional Dipolar Crystals

    E-Print Network [OSTI]

    Wolfgang Lechner; David Polster; Georg Maret; Christoph Dellago; Peter Keim

    2015-02-18

    We study in experiment and with computer simulation the free energy and the kinetics of vacancy and interstitial defects in two-dimensional dipolar crystals. The defects appear in different local topologies which we characterize by their point group symmetry; $C_n$ is the n-fold cyclic group and $D_n$ is the dihedral group, including reflections. The frequency of different local topologies is not determined by their almost degenerate energies but dominated by entropy for symmetric configurations. The kinetics of the defects is fully reproduced by a master equation in a multi-state Markov model. In this model, the system is described by the state of the defect and the time evolution is given by transitions occurring with particular rates. These transition rate constants are extracted from experiments and simulations using an optimisation procedure. The good agreement between experiment, simulation and master equation thus provides evidence for the accuracy of the model.

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

    E-Print Network [OSTI]

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

    2015-01-01

    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...

  10. Photonic-band-gap effects in two-dimensional polycrystalline and amorphous structures

    SciTech Connect (OSTI)

    Yang, Jin-Kyu; Noh, Heeso; Liew, Seng-Fatt; Schreck, Carl; Guy, Mikhael I.; O'Hern, Corey S.; Cao, Hui

    2010-11-15

    We study numerically the density of optical states (DOS) in two-dimensional photonic structures with short-range positional order and observe a transition from polycrystalline to amorphous photonic systems. In polycrystals, photonic band gaps (PBGs) are formed within individual domains, which leads to a depletion of the DOS similar to that in periodic structures. In amorphous photonic media, the domain sizes are too small to form PBGs, thus the depletion of the DOS is weakened significantly. The critical domain size that separates the polycrystalline and amorphous regimes is determined by the attenuation length of Bragg scattering, which depends not only on the degree of positional order but also the refractive-index contrast of the photonic material. Even with relatively low-refractive-index contrast, we find that modest short-range positional order in photonic structures enhances light confinement via collective scattering and interference.

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

    SciTech Connect (OSTI)

    Carr, Sam T.; Quintanilla, Jorge; Betouras, Joseph J.

    2010-07-15

    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.

  12. Analytical and numerical solution of one- and two-dimensional steady heat transfer in a coldplate

    SciTech Connect (OSTI)

    Jones, G.F.; Bennett, G.A.; Bultman, D.H.

    1987-01-01

    We develop analytical models for steady-state, one- and two-dimensional heat transfer in a single-material, flat-plate coldplate. Discrete heat sources are mounted on one side of the plate and heat transfer to a flowing fluid occurs on the other. The models are validated numerically using finite differences. We propose a simple procedure for estimating maximum coldplate temperature at the location of each heat source which includes thermal interaction among the sources. Results from one model are compared with data obtained for a composite coldplate operated in the laboratory. We demonstrate the utility of the models as diagnostic tools to be used for predicting the existence and extent of void volumes and delaminations in the composite material that can occur with coldplates of this type. Based on our findings, recommendations for effective coldplate design are given.

  13. Experimental test of a trace formula for two-dimensional dielectric resonators

    E-Print Network [OSTI]

    S. Bittner; E. Bogomolny; B. Dietz; M. Miski-Oglu; P. Oria Iriarte; A. Richter; F. Schäfer

    2010-06-21

    Resonance spectra of two-dimensional dielectric microwave resonators of circular and square shapes have been measured. The deduced length spectra of periodic orbits were analyzed and a trace formula for dielectric resonators recently proposed by Bogomolny et al. [Phys. Rev. E 78, 056202 (2008)] was tested. The observed deviations between the experimental length spectra and the predictions of the trace formula are attributed to a large number of missing resonances in the measured spectra. We show that by taking into account the systematics of observed and missing resonances the experimental length spectra are fully understood. In particular, a connection between the most long-lived resonances and certain periodic orbits is established experimentally.

  14. Bill2d -- a software package for classical two-dimensional Hamiltonian systems

    E-Print Network [OSTI]

    Solanpää, Janne; Räsänen, Esa

    2015-01-01

    We present Bill2d, a modern and efficient C++ package for classical simulations of two-dimensional Hamiltonian systems. Bill2d can be used for various billiard and diffusion problems with one or more charged particles with interactions, different external potentials, an external magnetic field, periodic and open boundaries, etc. The software package can also calculate many key quantities in complex systems such as Poincar\\'e sections, survival probabilities, and diffusion coefficients. While aiming at a large class of applicable systems, the code also strives for ease-of-use, efficiency, and modularity for the implementation of additional features. The package comes along with a user guide, a developer's manual, and a documentation of the application program interface (API).

  15. Wideband radar cross section reduction using two-dimensional phase gradient metasurfaces

    SciTech Connect (OSTI)

    Li, Yongfeng; Qu, Shaobo; Wang, Jiafu; Chen, Hongya; Zhang, Jieqiu; Xu, Zhuo; Zhang, Anxue

    2014-06-02

    Phase gradient metasurface (PGMs) are artificial surfaces that can provide pre-defined in-plane wave-vectors to manipulate the directions of refracted/reflected waves. In this Letter, we propose to achieve wideband radar cross section (RCS) reduction using two-dimensional (2D) PGMs. A 2D PGM was designed using a square combination of 49 split-ring sub-unit cells. The PGM can provide additional wave-vectors along the two in-plane directions simultaneously, leading to either surface wave conversion, deflected reflection, or diffuse reflection. Both the simulation and experiment results verified the wide-band, polarization-independent, high-efficiency RCS reduction induced by the 2D PGM.

  16. Transfer of optical signals around bends in two-dimensional linear photonic networks

    E-Print Network [OSTI]

    Georgios M. Nikolopoulos

    2014-11-13

    The ability to navigate light signals in two-dimensional networks of waveguide arrays is a prerequisite for the development of all-optical integrated circuits for information processing and networking. In this article, we present a theoretical analysis of bending losses in linear photonic lattices with engineered couplings, and discuss possible ways for their minimization. In contrast to previous work in the field, the lattices under consideration operate in the linear regime, in the sense that discrete solitons cannot exist. The present results suggest that the functionality of linear waveguide networks can be extended to operations that go beyond the recently demonstrated point-to-point transfer of signals, such as blocking, routing, logic functions, etc.

  17. Scaling properties of generalized two-dimensional Kuramoto-Sivashinsky equations

    E-Print Network [OSTI]

    Vaidas Juknevicius

    2015-05-09

    This paper presents numerical results for the two-dimensional isotropic Kuramoto-Sivashinsky equation (KSE) with an additional nonlinear term and a single independent parameter. Surfaces generated by this equation exhibit a certain dependence of the average saturated roughness on the system size that indicates power-law shape of the surface spectrum for small wave numbers. This leads to a conclusion that although cellular surface patterns of definite scale dominate in the range of short distances, there are also scale-free long-range height variations present in the large systems. The dependence of the spectral exponent on the equation parameter gives some insight into the scaling behavior for large systems.

  18. Passive tracer in a flow corresponding to a two dimensional stochastic Navier Stokes equations

    E-Print Network [OSTI]

    Tomasz Komorowski; Szymon Peszat; Tomasz Szarek

    2012-04-26

    In this paper we prove the law of large numbers and central limit theorem for trajectories of a particle carried by a two dimensional Eulerian velocity field. The field is given by a solution of a stochastic Navier--Stokes system with a non-degenerate noise. The spectral gap property, with respect to Wasserstein metric, for such a system has been shown in [9]. In the present paper we show that a similar property holds for the environment process corresponding to the Lagrangian observations of the velocity. In consequence we conclude the law of large numbers and the central limit theorem for the tracer. The proof of the central limit theorem relies on the martingale approximation of the trajectory process.

  19. A detailed two-dimensional stellar population study of M32

    E-Print Network [OSTI]

    C. del Burgo; R. F. Peletier; A. Vazdekis; S. Arribas; E. Mediavilla

    2000-09-01

    We present Two-Dimensional Spectroscopy of the 9x12 arcsec^2 central region of M32 obtained with the 2D_FIS fibre spectrograph installed at the William Herschel Telescope. From these spectra line strength maps have been reconstructed for about 20 absorption lines, mostly belonging to the Lick system. We find good agreement with long-slit line strength profiles in the literature. In contrast with previous studies, indices were azimuthally averaged along continuum isophotes of M32. A remarkable result is that no gradients are presented in the spectral indices. So, we have fitted the mean values of each spectral index and central colours to the models of Vazdekis et al. (1996) and Worthey (1994), finding that an intermediate age (~4 Gyr) and metallicity similar to solar (Z=0.02) are the best fitted values for the innermost region of M32.

  20. Laser induced reentrant freezing in two-dimensional attractive colloidal systems

    E-Print Network [OSTI]

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

    2005-09-11

    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.

  1. Freezing of a two dimensional fluid in to a crystalline phase : Density functional approach

    E-Print Network [OSTI]

    Anubha Jaiswal; Swarn L. Singh; Yashwant Singh

    2012-10-02

    A free-energy functional for a crystal proposed by Singh and Singh (Europhys. Lett. {\\bf {88}}, 16005 (2009)) and which contains both the symmetry conserved and symmetry broken parts of the direct pair correlation function has been used to investigate the crystallization of a two-dimensional fluid. The results found for fluids interacting via the inverse power potential $ u(r)= \\epsilon ({\\sigma}/{r})^{n} $ for n= 3, 6 and 12 are in good agreement with experimental and simulation results. The contribution made by the symmetry broken part to the grand thermodynamic potential at the freezing point is found to increase with the softness of the potential. Our results explain why the Ramakrishnan-Yussouff (Phys. Rev. B {\\bf 19}, 2775 (1979)) free-energy functional gave good account of freezing transitions of hard-core potentials but failed for potentials that have soft core and/or attractive tail.

  2. Laboratory setup and results of experiments on two-dimensional multiphase flow in porous media

    SciTech Connect (OSTI)

    McBride, J.F. (ed.) (Pacific Northwest Lab., Richland, WA (USA)); Graham, D.N. (ed.); Schiegg, H.O. (SIMULTEC Ltd., Meilen/Zurich (Switzerland))

    1990-10-01

    In the event of an accidental release into earth's subsurface of an immiscible organic liquid, such as a petroleum hydrocarbon or chlorinated organic solvent, the spatial and temporal distribution of the organic liquid is of great interest when considering efforts to prevent groundwater contamination or restore contaminated groundwater. An accurate prediction of immiscible organic liquid migration requires the incorporation of relevant physical principles in models of multiphase flow in porous media; these physical principles must be determined from physical experiments. This report presents a series of such experiments performed during the 1970s at the Swiss Federal Institute of Technology (ETH) in Zurich, Switzerland. The experiments were designed to study the transient, two-dimensional displacement of three immiscible fluids in a porous medium. This experimental study appears to be the most detailed published to date. The data obtained from these experiments are suitable for the validation and test calibration of multiphase flow codes. 73 refs., 140 figs.

  3. Wannier-Stark states in double-periodic lattices II: two-dimensional lattices

    E-Print Network [OSTI]

    E. N. Bulgakov; D. N. Maksimov; A. R. Kolovsky

    2014-11-24

    We analyze the Wannier-Stark spectrum of a quantum particle in tilted two-dimensional lattices with the Bloch spectrum consisting of two subbands, which could be either separated by a finite gap or connected at the Dirac points. For rational orientations of the static field given by an arbitrary superposition of the translation vectors the spectrum is a ladder of energy bands. We obtain asymptotic expressions for the energy bands in the limit of large and weak static fields and study them numerically for intermediate field strength. We show that the structure of energy bands determines the rate of spreading of a localized wave packets which is the quantity measured in laboratory experiments. It is shown that wave-packet dispersion becomes a fractal function of the field orientation in the long-time regime of ballistic spreading.

  4. Two-dimensional spectroscopy for the study of ion Coulomb crystals

    E-Print Network [OSTI]

    A. Lemmer; C. Cormick; C. T. Schmiegelow; F. Schmidt-Kaler; M. B. Plenio

    2015-05-04

    Ion Coulomb crystals are currently establishing themselves as a highly controllable test-bed for mesoscopic systems of statistical mechanics. The detailed experimental interrogation of the dynamics of these crystals however remains an experimental challenge. In this work, we show how to extend the concepts of multi-dimensional nonlinear spectroscopy to the study of the dynamics of ion Coulomb crystals. The scheme we present can be realized with state-of-the-art technology and gives direct access to the dynamics, revealing nonlinear couplings even in the presence of thermal excitations. We illustrate the advantages of our proposal showing how two-dimensional spectroscopy can be used to detect signatures of a structural phase transition of the ion crystal, as well as resonant energy exchange between modes. Furthermore, we demonstrate in these examples how different decoherence mechanisms can be identified.

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

    E-Print Network [OSTI]

    Nicholas Guttenberg; Nigel Goldenfeld

    2009-03-25

    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.

  6. Implementation of the Log-Conformation Formulation for Two-Dimensional Viscoelastic Flow

    E-Print Network [OSTI]

    Jensen, K E; Okkels, F

    2015-01-01

    We have implemented the log-conformation method for two-dimensional viscoelastic flow in COMSOL, a commercial high-level finite element package. The code is verified for an Oldroyd-B fluid flowing past a confined cylinder. We are also able to describe the well-known bistability of the viscoelastic flow in a cross-slot geometry for a FENE-CR fluid, and we describe the changes required for performing simulations with the Phan-Thien-Tanner (PTT), Giesekus and FENE-P models. Finally, we calculate the flow of a FENE-CR fluid in a geometry with three in- and outlets. The implementation is included in the supplementary material, and we hope that it can inspire new as well as experienced researchers in the field of differential constitutive equations for viscoelastic flow.

  7. Statistical Mechanics of Two-dimensional Foams: Physical Foundations of the Model

    E-Print Network [OSTI]

    Marc Durand

    2015-07-16

    In a recent series of papers [1--3], a statistical model that accounts for correlations between topological and geometrical properties of a two-dimensional shuffled foam has been proposed and compared with experimental and numerical data. Here, the various assumptions on which the model is based are exposed and justified: the equiprobability hypothesis of the foam configurations is argued. The range of correlations between bubbles is discussed, and the mean field approximation that is used in the model is detailed. The two self-consistency equations associated with this mean field description can be interpreted as the conservation laws of number of sides and bubble curvature, respectively. Finally, the use of a "Grand-Canonical" description, in which the foam constitutes a reservoir of sides and curvature, is justified.

  8. Dynamical generation of two-dimensional matter-wave discrete solitons

    E-Print Network [OSTI]

    Artem M. Dudarev; Roberto B. Diener; Qian Niu

    2004-02-21

    We suggest a method to experimentally obtain two-dimensional matter-wave discrete solitons with a {\\it self-repulsive} BEC in optical lattices. At the edge of the Brillouin zone, a wave packet effective mass is negative which could be treated as inversion of the nonlinearity sign. Above critical nonlinearity this makes the wave packets collapse partially into localized modes with a chemical potential located in the gap between the first and the second bands. This critical nonlinearity is also associated with the smallest nonlinearity for which the discrete solitons are possible in the gap. Extensive numerical simulations for square and asymmetric honeycomb lattices in continuous model illustrate every stage of the process.

  9. Two-dimensional modeling of the cathode sheath formation during the streamer-cathode interaction

    SciTech Connect (OSTI)

    Yan, Wen; Sang, Chaofeng; Wang, Dezhen, E-mail: wangdez@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Liu, Fucheng [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)] [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)

    2014-01-15

    In this paper, a computational simulation of the sheath formation during the streamer-surface interaction at atmospheric pressure is presented. A two-dimensional fluid model of a point-to-plane configuration is applied to investigate the evolution of the discharge in the vicinity of cathode plane. The effects of the surfaces on the properties of streamer have been studied for three cases, i.e., conductive surface with secondary electron emission (SEE), conductive surface without SEE, and dielectric surface. In all cases, we found that the axial propagation velocity of the streamer front decreases as the streamer arrives at the boundary of the cathode sheath. And the simulation results showed that the properties of the surface have a significant effect on the streamer. Besides the influences, the secondary emission coefficient and the relative permittivity on the streamer-surface interactions are also studied.

  10. Quantum Phase Transition in a Two-Dimensional System of Dipoles

    SciTech Connect (OSTI)

    Astrakharchik, G. E.; Boronat, J.; Kurbakov, I. L.; Lozovik, Yu. E.

    2007-02-09

    The ground-state phase diagram of a two-dimensional Bose system with dipole-dipole interactions is studied by means of a quantum Monte Carlo technique. Our calculation predicts a quantum phase transition from a gas to a solid phase when the density increases. In the gas phase, the condensate fraction is calculated as a function of the density. Using the Feynman approximation, the collective excitation branch is studied and the appearance of a roton minimum is observed. The results of the static structure factor at both sides of the gas-solid phase are also presented. The Lindemann ratio at the transition point becomes {gamma}=0.230(6). The condensate fraction in the gas phase is estimated as a function of the density.

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

    SciTech Connect (OSTI)

    Bender, M.D.; Shiao, Ming C.; Hauser, G.E. . Engineering Lab.); Butkus, S.R. . Water Quality Dept.)

    1990-09-01

    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.

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

    SciTech Connect (OSTI)

    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, Brasķlia - DF 70040-020 (Brazil)

    2014-06-15

    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.

  13. Linear and nonlinear stability analysis for two-dimensional ideal magnetohydrodynamics with incompressible flows

    SciTech Connect (OSTI)

    Khater, A.H.; Moawad, S.M.; Callebaut, D.K. [Department of Mathematics, Faculty of Science, Cairo University, Beni-Suef (Egypt); Departement Natuurkunde, Campus Drie Eiken, Universiteit Antwerpen - UA, B-2610 Antwerpen (Belgium)

    2005-01-01

    The equilibrium and Lyapunov stability properties for two-dimensional ideal magnetohydrodynamic (MHD) plasmas with incompressible and homogeneous (i.e., constant density) flows are investigated. In the unperturbed steady state, both the velocity and magnetic field are nonzero and have three components in a Cartesian coordinate system with translational symmetry (i.e., one ignorable spatial coordinate). It is proved that (a) the solutions of the ideal MHD steady state equations with incompressible and homogeneous flows in the plane are also valid for equilibria with the axial velocity component being a free flux function and the axial magnetic field component being a constant (b) the conditions of linearized Lyapunov stability for these MHD flows in the planar case (in which the fields have only two components) are also valid for symmetric equilibria that have a nonplanar velocity field component as well as a nonplanar magnetic field component. On using the method of convexity estimates, nonlinear stability conditions are established.

  14. A Priori Estimates for Two-Dimensional Water Waves with Angled Crests

    E-Print Network [OSTI]

    Kinsey, Rafe H

    2014-01-01

    We consider the two-dimensional water wave problem in the case where the free interface of the fluid meets a vertical wall at a possibly non-right angle; our problem also covers interfaces with angled crests. We assume that the fluid is inviscid, incompressible, and irrotational, with no surface tension and with air density zero. We construct a low-regularity energy and prove a closed energy estimate for this problem. Our work differs from earlier work in that, in our case, only a degenerate Taylor stability criterion holds, with $-\\frac{\\partial P}{\\partial {\\bf n}} \\ge 0$, instead of the strong Taylor stability criterion $-\\frac{\\partial P}{\\partial {\\bf n}} \\ge c > 0$.

  15. Two-dimensional positive column structure in a discharge tube with radius discontinuity

    SciTech Connect (OSTI)

    Zobnin, A. V. Usachev, A. D.; Petrov, O. F.; Fortov, V. E.

    2014-11-15

    The low-pressure (40 and 90?Pa) low-current (4 and 10?mA) direct current discharge in a tube with a sharp change of its radius is studied both numerically and experimentally. A fully self-consistent hybrid numerical model of a two-dimensional non-uniform positive column in neon is developed using a nonlocal approach. The model combines kinetic simulation of the electrons (under two-terms approach) and fluid description of the neon ions and permits to calculate the distribution of all plasma parameters in the direct current discharges in the cameras with cylindrical geometry and radius discontinuity. The simulation results are compared with the measured 585.3?nm neon spectral line absolute intensities and excited 1s{sub 3} metastable neon atom number densities. Non-local electron kinetics in the transition region and formation of standing strata are discussed.

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

    SciTech Connect (OSTI)

    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)

    2014-11-15

    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.

  17. Finite-time barriers to front propagation in two-dimensional fluid flows

    E-Print Network [OSTI]

    Mahoney, John R

    2015-01-01

    Recent theoretical and experimental investigations have demonstrated the role of certain invariant manifolds, termed burning invariant manifolds (BIMs), as one-way dynamical barriers to reaction fronts propagating within a flowing fluid. These barriers form one-dimensional curves in a two-dimensional fluid flow. In prior studies, the fluid velocity field was required to be either time-independent or time-periodic. In the present study, we develop an approach to identify prominent one-way barriers based only on fluid velocity data over a finite time interval, which may have arbitrary time-dependence. We call such a barrier a burning Lagrangian coherent structure (bLCS) in analogy to Lagrangian coherent structures (LCSs) commonly used in passive advection. Our approach is based on the variational formulation of LCSs using curves of stationary "Lagrangian shear", introduced by Farazmand, Blazevski, and Haller [Physica D 278-279, 44 (2014)] in the context of passive advection. We numerically validate our techniqu...

  18. Epitaxial two-dimensional nitrogen atomic sheet in GaAs

    SciTech Connect (OSTI)

    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)

    2014-01-27

    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.

  19. One- and two-dimensional simulations of ultra-short-pulse reflectometry

    SciTech Connect (OSTI)

    Cohen, B.I.; Kaiser, T.B.; Garrison, J.C.

    1997-02-01

    Ultra-short-pulse reflectometry is studied by means of the numerical integration of one- and two-dimensional full-wave equations for ordinary and extraordinary modes propagating in a plasma. The numerical calculations illustrate the use of the reflection of ultra-short-pulse microwaves as an effective probe of the density or magnetic profile in the presence of density or magnetic fluctuations in the plasma. Bragg resonance effects can be identified in the reflected signals, which give information on fluctuations. It is also demonstrated that ultra-short-pulse reflectometry can be used to perform correlation reflectometry measurements in which correlation lengths for density fluctuations are deduced from the observed cross-correlation function of phase shifts as a function of frequency. {copyright} {ital 1997 American Institute of Physics.}

  20. One- and two-dimensional simulations of ultra-short-pulse reflectometry

    SciTech Connect (OSTI)

    Cohen, B.I.; Kaiser, T.B.; Garrison, J.C.

    1997-01-01

    Ultra-short-pulse reflectometry is studied by means of the numerical integration of one- and two-dimensional full-wave equations for ordinary and extraordinary modes propagating in a plasma. The numerical calculations illustrate the use of the reflection of ultra-short-pulse microwaves as an effective probe of the density or magnetic profile in the presence of density or magnetic fluctuations in the plasma. Bragg resonance effects can be identified in the reflected signals, which give information on fluctuations. It is also demonstrated that ultra-short-pulse reflectometry can be used to perform correlation reflectometry measurements in which correlation lengths for density fluctuations are deduced from the observed cross-correlation function of phase shifts as a function of frequency. {copyright} {ital 1997 American Institute of Physics.}

  1. Fuel-air mixing and combustion in a two-dimensional Wankel engine

    SciTech Connect (OSTI)

    Shih, T.I.P.; Schock, H.J.; Ramos, J.I.

    1987-01-01

    The effects of mixture stratification at the intake port and gaseous fuel injection on the flow field and fuel-air mixing in a two-dimensional rotary engine model have been investigated by means of a two-equation model of turbulence, an algebraic grid generation method and an approximate factorization time-linearized numerical technique. It is shown that the fuel distribution in the combustion chamber is a function of the air-fuel mixture fluctuations at the intake port. The fuel is advected by the flow field induced by the rotor and is concentrated near the leading apex during the intake stroke. During compression, the fuel concentration is highest near the trailing apex and lowest near the rotor. The penetration of gaseous fuel injected into the combustion chamber during the compression stroke increases with the injection velocity.

  2. Collision-dependent power law scalings in two dimensional gyrokinetic turbulence

    SciTech Connect (OSTI)

    Cerri, S. S. Bańón Navarro, A.; Told, D.; Jenko, F.

    2014-08-15

    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.

  3. Dynamical Mechanism of Two-Dimensional Plasmon Launching by Swift Electrons

    E-Print Network [OSTI]

    Xiao Lin; Xihang Shi; Fei Gao; Ido Kaminer; Zhaoju Yang; Zhen Gao; Hrvoje Buljan; John D. Joannopoulos; Marin Solja?i?; Hongsheng Chen; Baile Zhang

    2015-07-30

    Launching of surface plasmons by swift electrons has long been utilized to investigate plasmonic properties of ultrathin, or two-dimensional (2D), electron systems, including graphene plasmons recently. However, spatio-temporal dynamics of this process has never been clearly revealed. This is because the impact of an electron will generate not only plasmons, but also photons, demanding both space and time. Here we address this issue within the framework of classical electromagnetics by showing the dynamical process of 2D plasmon launching by swift electrons on graphene. The launching of 2D plasmons on graphene is not immediate, but is delayed after a hydrodynamic splashing-like process, which occurs during the formation time of transition radiation caused by the electron's impact. This newly revealed process also implies that all previous estimates on the yields of graphene plasmons in electron-energy-loss-spectroscopy have been overestimated.

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

    SciTech Connect (OSTI)

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

    1996-03-01

    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.

  5. Thermoelectric probe for Rashba spin-orbit interaction strength in a two dimensional electron gas

    E-Print Network [OSTI]

    S. K. Firoz Islam; Tarun Kanti Ghosh

    2012-07-18

    Thermoelectric coefficients of a two dimensional electron gas with the Rashba spin-orbit interaction are presented here. In absence of magnetic field, thermoelectric coefficients are enhanced due to the Rashba spin-orbit interaction. In presence of magnetic field, the thermoelectric coefficients of spin-up and spin-down electrons oscillate with different frequency and produces beating patterns in the components of the total thermoelectric power and the total thermal conductivity. We also provide analytical expressions of the thermoelectric coefficients to explain the beating pattern formation. We obtain a simple relation which determines the Rashba SOI strength if the magnetic fields corresponding to any two successive beat nodes are known from the experiment.

  6. Performance and Error Analysis of Knill's Postselection Scheme in a Two-Dimensional Architecture

    E-Print Network [OSTI]

    Ching-Yi Lai; Gerardo Paz; Martin Suchara; Todd A. Brun

    2013-05-31

    Knill demonstrated a fault-tolerant quantum computation scheme based on concatenated error-detecting codes and postselection with a simulated error threshold of 3% over the depolarizing channel. %We design a two-dimensional architecture for fault-tolerant quantum computation based on Knill's postselection scheme. We show how to use Knill's postselection scheme in a practical two-dimensional quantum architecture that we designed with the goal to optimize the error correction properties, while satisfying important architectural constraints. In our 2D architecture, one logical qubit is embedded in a tile consisting of $5\\times 5$ physical qubits. The movement of these qubits is modeled as noisy SWAP gates and the only physical operations that are allowed are local one- and two-qubit gates. We evaluate the practical properties of our design, such as its error threshold, and compare it to the concatenated Bacon-Shor code and the concatenated Steane code. Assuming that all gates have the same error rates, we obtain a threshold of $3.06\\times 10^{-4}$ in a local adversarial stochastic noise model, which is the highest known error threshold for concatenated codes in 2D. We also present a Monte Carlo simulation of the 2D architecture with depolarizing noise and we calculate a pseudo-threshold of about 0.1%. With memory error rates one-tenth of the worst gate error rates, the threshold for the adversarial noise model, and the pseudo-threshold over depolarizing noise, are $4.06\\times 10^{-4}$ and 0.2%, respectively. In a hypothetical technology where memory error rates are negligible, these thresholds can be further increased by shrinking the tiles into a $4\\times 4$ layout.

  7. Seismic reflection investigations of sinkholes beneath Interstate Highway 70 in Kansas

    E-Print Network [OSTI]

    Steeples, Don W.; Knapp, Ralph W.; McElwee, Carl D.

    1986-02-01

    Seismic reflection studies were performed across actively developing sinkholes located astride Interstate Highway 70 in Russell County, Kansas. Results indicate that high?resolution seismic reflection surveys are useful in the subsurface...

  8. 5D seismic data completion and denoising using a novel class of tensor decompositions

    E-Print Network [OSTI]

    Aeron, Shuchin

    We have developed a novel strategy for simultaneous interpolation and denoising of prestack seismic data. Most seismic surveys fail to cover all possible source-receiver combinations, leading to missing data especially in ...

  9. 3-D seismic surveys generate 5-D data volume. In order to estimate the horizons for interpretation and further processing, the traveltime picking needs to be performed on n-D subsets of this 5-D data volume (n5). Horizon

    E-Print Network [OSTI]

    Nicoli, Monica

    Abstract 3-D seismic surveys generate 5-D data volume. In order to estimate the horizons for interpretation and further processing, the traveltime picking needs to be performed on n-D subsets of this 5-D to support the interpreters in the estimation of the events by preserving their depth continuity. The HP

  10. DRAFT TECHNICAL GUIDANCE DOCUMENT ON STATIC AND SEISMIC SLOPE STABILITY FOR SOLID WASTE

    E-Print Network [OSTI]

    stability of landfill slopes. Locating the critical cross- section is usually accomplished by analyzing two of landfill slopes. The two-dimensional cross-sections are usually analyzed using a limit equilibrium slope- and post-closure conditions (e.g., seismic events, settlement, and expansion). o Settlement caused

  11. Coexistence of Magnetic Order and Two-dimensional Superconductivity at LaAlO3/SrTiO3 Interfaces

    E-Print Network [OSTI]

    Li, Lu

    A two dimensional electronic system forms at the interface between the band insulators LaAlO[subscript 3]

  12. Two-dimensional inverse planning and delivery with a preclinical image guided microirradiator

    SciTech Connect (OSTI)

    Stewart, James M. P.; Lindsay, Patricia E.; Jaffray, David A.; Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario M5G 2M9; Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 3E2; Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 2M9; The Techna Institute for the Advancement of Technology for Health, Toronto, Ontario M5G 1P5

    2013-10-15

    Purpose: Recent advances in preclinical radiotherapy systems have provided the foundation for scaling many of the elements of clinical radiation therapy practice to the dimensions and energy demanded in small animal studies. Such systems support the technical capabilities to accurately deliver highly complex dose distributions, but methods to optimize and deliver such distributions remain in their infancy. This study developed an optimization method based on empirically measured two-dimensional dose kernel measurements to deliver arbitrary planar dose distributions on a recently developed small animal radiotherapy platform.Methods: A two-dimensional dose kernel was measured with repeated radiochromic film measurements for the circular 1 mm diameter fixed collimator of the small animal radiotherapy system at 1 cm depth in a solid water phantom. This kernel was utilized in a sequential quadratic programming optimization framework to determine optimal beam positions and weights to deliver an arbitrary desired dose distribution. The positions and weights were then translated to a set of stage motions to automatically deliver the optimized dose distribution. End-to-end efficacy of the framework was quantified through five repeated deliveries of two dosimetric challenges: (1) a 5 mm radius bullseye distribution, and (2) a “sock” distribution contained within a 9 × 13 mm bounding box incorporating rectangular, semicircular, and exponentially decaying geometric constructs and a rectangular linear dose gradient region. These two challenges were designed to gauge targeting, geometric, and dosimetric fidelity.Results: Optimization of the bullseye and sock distributions required 2.1 and 5.9 min and utilized 50 and 77 individual beams for delivery, respectively. Automated delivery of the resulting optimized distributions, validated using radiochromic film measurements, revealed an average targeting accuracy of 0.32 mm, and a dosimetric delivery error along four line profiles taken through the sock distribution of 3.9%. Mean absolute delivery error across the 0–1 Gy linear dose gradient over 7.5 mm was 0.01 Gy.Conclusions: The work presented here demonstrates the potential for complex dose distributions to be planned and automatically delivered with millimeter scale heterogeneity at submillimeter accuracy. This capability establishes the technical foundation for preclinical validation of biologically guided radiotherapy investigations and development of unique radiobiological experiments.

  13. Interpreting multicomponent seismic data in the Gulf of Mexico for shallow sedimentary properties: methodology and case history

    E-Print Network [OSTI]

    Texas at Austin, University of

    OTC 15118 Interpreting multicomponent seismic data in the Gulf of Mexico for shallow sedimentary a methodology for manually establishing tie points of depth-equivalent surfaces in P-P and P-S seismic data volumes derived from a 4-C ocean bottom seismic survey using seismic attribute volumes viewed in time

  14. Self Organized Criticality in a two dimensional Cellular Automaton model of a magnetic flux tube with background flow

    E-Print Network [OSTI]

    Danila, Bogdan; Mocanu, Gabriela

    2015-01-01

    We investigate the transition to Self Organized Criticality in a two-dimensional model of a flux tube with a background flow. The magnetic induction equation, represented by a partial differential equation with a stochastic source term, is discretized and implemented on a two dimensional cellular automaton. The energy released by the automaton during one relaxation event is the magnetic energy. As a result of the simulations we obtain the time evolution of the energy release, of the system control parameter, of the event lifetime distribution and of the event size distribution, respectively, and we establish that a Self Organized Critical state is indeed reached by the system. Moreover, energetic initial impulses in the magnetohydrodynamic flow can lead to one dimensional signatures in the magnetic two dimensional system, once the Self Organized Critical regime is established. The applications of the model for the study of Gamma Ray Bursts is briefly considered, and it is shown that some astrophysical paramet...

  15. Excitation, detection, and electrostatic manipulation of terahertz-frequency range plasmons in a two-dimensional electron system

    E-Print Network [OSTI]

    Wu, Jingbo; Wood, Christopher D; Mistry, Divyang; Li, Lianhe; Muchenje, Wilson; Rosamond, Mark C; Chen, Li; Linfield, Edmund H; Davies, A Giles; Cunningham, John E

    2015-01-01

    Terahertz time domain spectroscopy employing free-space radiation has frequently been used to probe the elementary excitations of low-dimensional systems. The diffraction limit blocks its use for the in-plane study of individual laterally defined nanostructures, however. Here, we demonstrate a planar terahertz-frequency plasmonic circuit in which photoconductive material is monolithically integrated with a two-dimensional electron system. Plasmons with a broad spectral range (up to ~400 GHz) are excited by injecting picosecond-duration pulses, generated and detected by a photoconductive semiconductor, into a high mobility two-dimensional electron system. Using voltage modulation of a Schottky gate overlying the two-dimensional electron system, we form a tuneable plasmonic cavity, and observe electrostatic manipulation of the plasmon resonances. Our technique offers a direct route to access the picosecond dynamics of confined transport in a broad range of lateral nanostructures.

  16. Nano-Scale Hydroxyapatite: Synthesis, Two-Dimensional Transport Experiments, and Application for Uranium Remediation

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

    Kanel, S. R.; Clement, T. P.; Barnett, M. O.; Goltz, M. N.

    2011-01-01

    Synthetic nano-scale hydroxyapatite (NHA) was prepared and characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. The XRD data confirmed that the crystalline structure and chemical composition of NHA correspond to Ca 5 OH(PO 4 ) 3 . The SEM data confirmed the size of NHA to be less than 50?nm. A two-dimensional physical model packed with saturated porous media was used to study the transport characteristics of NHA under constant flow conditions. The data show that the transport patterns of NHA were almost identical to tracer transport patterns. This result indicates that the NHA material canmore »move with water like a tracer, and its movement was neither retarded nor influenced by any physicochemical interactions and/or density effects. We have also tested the reactivity of NHA with 1?mg/L hexavalent uranium (U(VI)) and found that complete removal of U(VI) is possible using 0.5?g/L NHA at pH?5 to 6. Our results demonstrate that NHA has the potential to be injected as a dilute slurry for in situ treatment of U(VI)-contaminated groundwater systems. « less

  17. Simulations of spray autoignition and flame establishment with two-dimensional CMC

    SciTech Connect (OSTI)

    Wright, Y.M.; Boulouchos, K. [Aerothermochemistry and Combustion Technology Laboratory, ETH Zurich (Switzerland); De Paola, G.; Mastorakos, E. [Hopkinson Laboratory, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom)

    2005-12-01

    The unsteady two-dimensional conditional moment closure (CMC) model with first-order closure of the chemistry and supplied with standard models for the conditional convection and turbulent diffusion terms has been interfaced with a commercial engine CFD code and analyzed with two numerical methods, an 'exact' calculation with the method of lines and a faster fractional-step method. The aim was to examine the sensitivity of the predictions to the operator splitting errors and to identify the extent to which spatial transport terms are important for spray autoignition problems. Despite the underlying simplifications, solution of the full CMC equations allows a single model to be used for the autoignition, flame propagation ('premixed mode'), and diffusion flame mode of diesel combustion, which makes CMC a good candidate model for practical engine calculations. It was found that (i) the conditional averages have significant spatial gradients before ignition and during the premixed mode and (ii) that the inclusion of physical-space transport affects the calculation of the autoignition delay time, both of which suggest that volume-averaged CMC approaches may be inappropriate for diesel-like problems. A balance of terms in the CMC equation before and after autoignition shows the relative magnitude of spatial transport and allows conjectures on the structure of the premixed phase of diesel combustion. Very good agreement with available experimental data is found concerning ignition delays and the effect of background air turbulence on them.

  18. Two dimensional Sen connections and quasi-local energy-momentum

    E-Print Network [OSTI]

    L. B. Szabados

    1994-02-02

    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.

  19. The Massive Goldstone (Higgs) Mode in Two-Dimensional Ultra-cold Atomic Lattice Systems

    E-Print Network [OSTI]

    Liu, Longxiang; Endres, Manuel; Deng, Youjin; Pollet, Lode; Prokof'ev, Nikolay

    2015-01-01

    We discuss how to reveal the massive Goldstone mode, often referred to as the Higgs amplitude mode, near the Superfluid-to-Insulator quantum critical point (QCP) in a system of two-dimensional ultra-cold bosonic atoms in optical lattices. The spectral function of the amplitude response is obtained by analytic continuation of the kinetic energy correlation function calculated by Monte Carlo methods. Our results enable a direct comparison with the recent experiment [M. Endres, T. Fukuhara, D. Pekker, M. Cheneau, P. Schau{\\ss}, C. Gross, E. Demler, S. Kuhr, and I. Bloch, Nature 487, 454-458 (2012)], and demonstrate a good agreement for temperature shifts induced by lattice modulation. Based on our numerical analysis, we formulate the necessary conditions in terms of homogeneity, detuning from the QCP and temperature in order to reveal the massive Goldstone resonance peak in spectral functions experimentally. We also propose to apply a local modulation at the trap center to overcome the inhomogeneous broadening c...

  20. Basin boundary, edge of chaos, and edge state in a two-dimensional model

    E-Print Network [OSTI]

    J. Vollmer; T. M. Schneider; B. Eckhardt

    2008-08-19

    In shear flows like pipe flow and plane Couette flow there is an extended range of parameters where linearly stable laminar flow coexists with a transient turbulent dynamics. When increasing the amplitude of a perturbation on top of the laminar flow, one notes a a qualitative change in its lifetime, from smoothly varying and short one on the laminar side to sensitively dependent on initial conditions and long on the turbulent side. The point of transition defines a point on the edge of chaos. Since it is defined via the lifetimes, the edge of chaos can also be used in situations when the turbulence is not persistent. It then generalises the concept of basin boundaries, which separate two coexisting attractors, to cases where the dynamics on one side shows transient chaos and almost all trajectories eventually end up on the other side. In this paper we analyse a two-dimensional map which captures many of the features identified in laboratory experiments and direct numerical simulations of hydrodynamic flows. The analysis of the map shows that different dynamical situations in the edge of chaos can be combined with different dynamical situations in the turbulent region. Consequently, the model can be used to develop and test further characterisations that are also applicable to realistic flows.

  1. Contact research strategy for emerging molybdenum disulfide and other two-dimensional field-effect transistors

    SciTech Connect (OSTI)

    Du, Yuchen; Yang, Lingming; Liu, Han; Ye, Peide D., E-mail: yep@purdue.edu [School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)

    2014-09-01

    Layered two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) have been widely isolated, synthesized, and characterized recently. Numerous 2D materials are identified as the potential candidates as channel materials for future thin film technology due to their high mobility and the exhibiting bandgaps. While many TMD filed-effect transistors (FETs) have been widely demonstrated along with a significant progress to clearly understand the device physics, large contact resistance at metal/semiconductor interface still remain a challenge. From 2D device research point of view, how to minimize the Schottky barrier effects on contacts thus reduce the contact resistance of metals on 2D materials is very critical for the further development of the field. Here, we present a review of contact research on molybdenum disulfide and other TMD FETs from the fundamental understanding of metal-semiconductor interfaces on 2D materials. A clear contact research strategy on 2D semiconducting materials is developed for future high-performance 2D FETs with aggressively scaled dimensions.

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

    E-Print Network [OSTI]

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

    2015-02-04

    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.

  3. Transition in heterogeneous dynamics across the morphological hierarchy in two-dimensional aggregates

    E-Print Network [OSTI]

    Tamoghna Das; T. Lookman; M. M. Bandi

    2015-05-21

    Two-dimensional (2D) particulate aggregates formed due to competing interactions exhibit a range of non-equilibrium steady state morphologies from finite-size compact crystalline structures to non-compact string-like conformations. We report a transition in heterogeneous microscopic dynamics across this morphological hierarchy as a function of decreasing long-range repulsion relative to short-range attraction at a constant {\\it low} density and temperature. Following a very slow cooling protocol to form steady state aggregates, we show that geometric frustration inherent to competing interactions assures non-ergodicity of the system, which in turn results in long-time sub diffusive relaxation of the same. Analysing individual particle trajectories generated by molecular dynamics, we identify {\\it caging} dynamics of particles in compact clusters in contrast to the {\\it bonding} scenario for non-compact ones. Finally, by monitoring temperature dependence, we present a generic relation between diffusivity and structural randomness of the aggregates, irrespective of their thermodynamic equilibrium.

  4. Coherent Structures in Turbulent Flow over Two-Dimensional River Dunes

    E-Print Network [OSTI]

    Omidyeganeh, Mohammad

    2011-01-01

    We performed large-eddy simulations of the flow over a typical two-dimensional dune geometry at laboratory scale (the Reynolds number based on the average channel height and mean velocity is 18,900) using the Lagrangian dynamic eddy-viscosity subgrid-scale model. The flow separates at the dune crest and reattaches downstream on the bed (at x=5.7h). A favorable pressure gradient accelerates the flow over the stoss-side (the upward-sloping region for x > 8h) and an unfavorable gradient for x dune. Due to the separation of the flow, a shear layer is generated after the crest that expands in the wake region towards the next dune. The outer-layer turbulence structures are visualized through isosurfaces of pressure fluctuations colored by distance to the surface. Spanwise vortices are generated in the shear layer separating from the crest due to the Kelvin-Helmholtz instability. They are convected downstream and either interact with the wall or rise to the surfa...

  5. Universal Conductivity in a Two-dimensional Superfluid-to-Insulator Quantum Critical System

    E-Print Network [OSTI]

    Chen, Kun; Deng, Youjin; Pollet, Lode; Prokof'ev, Nikolay

    2013-01-01

    We compute the universal conductivity of the (2+1)-dimensional XY universality class, which is realized for a superfluid-to-Mott insulator quantum phase transition at constant density. Based on large-scale Monte Carlo simulations of the classical (2+1)-dimensional $J$-current model and the two-dimensional Bose-Hubbard model, we can precisely determine the conductivity on the quantum critical plateau, $\\sigma(\\infty)=0.359(4)\\sigma_Q$ with $\\sigma_Q$ the conductivity quantum. The universal conductivity is the schoolbook example of where the AdS/CFT correspondence from string theory can be tested and made to use. The shape of our $\\sigma(i\\omega_n)- \\sigma(\\infty)$ function in the Matsubara representation is accurate enough for a conclusive comparison and establishes the particle-like nature of charge transport. We find that the holographic gauge/gravity duality theory for transport properties can be made compatible with the data if temperature of the horizon of the black brane is different from the temperature...

  6. Quantum fluctuations in the BCS-BEC crossover of two-dimensional Fermi gases

    E-Print Network [OSTI]

    He, Lianyi; Cao, Gaoqing; Hu, Hui; Liu, Xia-Ji

    2015-01-01

    We present a theoretical study of the ground state of the BCS-BEC crossover in dilute two-dimensional Fermi gases. While the mean-field theory provides a simple and analytical equation of state, the pressure is equal to that of a noninteracting Fermi gas in the entire BCS-BEC crossover, which is not consistent with the features of the weakly interacting Bose condensate in the BEC limit and the weakly interacting Fermi liquid in the BCS limit. The inadequacy of the 2D mean-field theory indicates that the quantum fluctuations are much more pronounced than those in 3D. In this work, we show that the inclusion of the Gaussian quantum fluctuations naturally recovers the above features in both the BEC and BCS limits. In the BEC limit, the missing logarithmic dependence on the boson chemical potential is recovered by the quantum fluctuations. Near the quantum phase transition from the vacuum to the BEC phase, we compare our equation of state with the known grand canonical equation of state of 2D Bose gases and deter...

  7. Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots

    DOE Patents [OSTI]

    Zhang, Jian-Shi; Giometti, C.S.; Tollaksen, S.L.

    1987-09-04

    After two-dimensional electrophoresis of proteins or the like, resulting in a polyacrylamide gel slab having a pattern of protein gel spots thereon, an individual protein gel spot is cored out from the slab, to form a gel spot core which is placed in an extraction tube, with a dialysis membrane across the lower end of the tube. Replicate gel spots can be cored out from replicate gel slabs and placed in the extraction tube. Molten agarose gel is poured into the extraction tube where the agarose gel hardens to form an immobilizing gel, covering the gel spot cores. The upper end portion of the extraction tube is filled with a volume of buffer solution, and the upper end is closed by another dialysis membrane. Upper and lower bodies of a buffer solution are brought into contact with the upper and lower membranes and are provided with electrodes connected to the positive and negative terminals of a dc power supply, thereby producing an electrical current which flows through the upper membrane, the volume of buffer solution, the agarose, the gel spot cores and the lower membrane. The current causes the proteins to be extracted electrophoretically from the gel spot cores, so that the extracted proteins accumulate and are contained in the space between the agarose gel and the upper membrane. 8 figs.

  8. Unveiling Surface Redox Charge Storage of Interacting Two-Dimensional Hetero-Nanosheets in Hierarchical Architectures

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

    Mahmood, Qasim [Department of Chemical Engineering, College of Engineering, Kyung Hee University (Republic of Korea); Bak, Seong-Min [Brookhaven National Laboratory (BNL), Upton, NY (United States); Kim, Min G. [Beamline Research Division, Pohang Accelerator Laboratory, Pohang (Republic of Korea); Yun, Sol [School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon (Republic of Korea); Yang, Xiao-Qing [Brookhaven National Laboratory (BNL), Upton, NY (United States); Shin, Hyeon S. [Department of Energy Engineering, Department of Chemistry, and Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology(UNIST) (Republic of Korea); Kim, Woo S. [Department of Chemical Engineering, College of Engineering, Kyung Hee University (Republic of Korea); Braun, Paul V. [Department of Materials Science and Engineering Materials Research Laboratory and Beckman Institute, University of Illinois at Urbana?Champaign, Urbana, Illinois (United States); Park, Ho S. [School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon (Republic of Korea)

    2015-04-08

    Two-dimensional (2D) heteronanosheets are currently the focus of intense study due to the unique properties that emerge from the interplay between two low-dimensional nanomaterials with different properties. However, the properties and new phenomena based on the two 2D heteronanosheets interacting in a 3D hierarchical architecture have yet to be explored. Here, we unveil the surface redox charge storage mechanism of surface-exposed WS2 nanosheets assembled in a 3D hierarchical heterostructure using in situ synchrotron X-ray absorption and Raman spectroscopic methods. The surface dominating redox charge storage of WS2 is manifested in a highly reversible and ultrafast capacitive fashion due to the interaction of heteronanosheets and the 3D connectivity of the hierarchical structure. In contrast, compositionally identical 2D WS2 structures fail to provide a fast and high capacitance with different modes of lattice vibration. The distinctive surface capacitive behavior of 3D hierarchically structured heteronanosheets is associated with rapid proton accommodation into the in-plane W–S lattice (with the softening of the E2g bands), the reversible redox transition of the surface-exposed intralayers residing in the electrochemically active 1T phase of WS2 (with the reversible change in the interatomic distance and peak intensity of W–W bonds), and the change in the oxidation state during the proton insertion/deinsertion process. This proposed mechanism agrees with the dramatic improvement in the capacitive performance of the two heteronanosheets coupled in the hierarchical structure.

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

    SciTech Connect (OSTI)

    Mario Agio

    2002-12-31

    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.

  10. Anisotropic characteristics of the Kraichnan direct cascade in two-dimensional hydrodynamic turbulence

    E-Print Network [OSTI]

    Kuznetsov, E A

    2015-01-01

    Statistical characteristics of the Kraichnan direct cascade for two-dimensional hydrodynamic turbulence are numerically studied (with spatial resolution $8192\\times 8192$) in the presence of pumping and viscous-like damping. It is shown that quasi-shocks of vorticity and their Fourier partnerships in the form of jets introduce an essential influence in turbulence leading to strong angular dependencies for correlation functions. The energy distribution as a function of modulus $k$ for each angle in the inertial interval has the Kraichnan behavior, $\\sim k^{-4}$, and simultaneously a strong dependence on angles. However, angle average provides with a high accuracy the Kraichnan turbulence spectrum $E_k=C_K\\eta^{2/3} k^{-3}$ where $\\eta$ is enstrophy flux and the Kraichnan constant $C_K\\simeq 1.3$, in correspondence with the previous simulations. Familiar situation takes place for third-order velocity structure function $S_3^L$ which, as for the isotropic turbulence, gives the same scaling with respect to separa...

  11. Anisotropic characteristics of the Kraichnan direct cascade in two-dimensional hydrodynamic turbulence

    E-Print Network [OSTI]

    E. A. Kuznetsov; E. V. Sereshchenko

    2015-10-30

    Statistical characteristics of the Kraichnan direct cascade for two-dimensional hydrodynamic turbulence are numerically studied (with spatial resolution $8192\\times 8192$) in the presence of pumping and viscous-like damping. It is shown that quasi-shocks of vorticity and their Fourier partnerships in the form of jets introduce an essential influence in turbulence leading to strong angular dependencies for correlation functions. The energy distribution as a function of modulus $k$ for each angle in the inertial interval has the Kraichnan behavior, $\\sim k^{-4}$, and simultaneously a strong dependence on angles. However, angle average provides with a high accuracy the Kraichnan turbulence spectrum $E_k=C_K\\eta^{2/3} k^{-3}$ where $\\eta$ is enstrophy flux and the Kraichnan constant $C_K\\simeq 1.3$, in correspondence with the previous simulations. Familiar situation takes place for third-order velocity structure function $S_3^L$ which, as for the isotropic turbulence, gives the same scaling with respect to separation length $R$ and $\\eta$, $S_3^L=C_3\\eta R^3$, but the mean over angles and time $\\bar {C_3}$ differs from its isotropic value.

  12. Towards enhancing two-dimensional electron gas quantum confinement effects in perovskite oxide heterostructures

    SciTech Connect (OSTI)

    Nazir, Safdar; Behtash, Maziar; Yang, Kesong

    2015-03-21

    We explore the possibility of achieving highly confined two-dimensional electron gas (2DEG) within one single atomic layer through a comprehensive comparison study on three prototypical perovskite heterostructures, LaAlO{sub 3}/ATiO{sub 3} (A = Ca, Sr, and Ba), using first-principles electronic structure calculations. We predict that the heterostructure LaAlO{sub 3}/BaTiO{sub 3} has a highly confined 2DEG within a single atomic layer of the substrate BaTiO{sub 3}, and exhibits relatively higher interfacial charge carrier density and larger magnetic moments than the well-known LaAlO{sub 3}/SrTiO{sub 3} system. The long Ti-O bond length in the ab-plane of the LaAlO{sub 3}/BaTiO{sub 3} heterostructure is responsible for the superior charge confinement. We propose BaTiO{sub 3} as an exceptional substrate material for 2DEG systems with potentially superior properties.

  13. Quantifying Resonant Structure in NGC 6946 from Two-dimensional Kinematics

    E-Print Network [OSTI]

    Fathi, Kambiz; Falcón-Barroso, Jesśs; Beckman, John E; Hernandez, Olivier; Daigle, Olivier; Carignan, Claude; de Zeeuw, Tim

    2007-01-01

    We study the two-dimensional kinematics of the H-alpha-emitting gas in the nearby barred Scd galaxy, NGC 6946, in order to determine the pattern speed of the primary m=2 perturbation mode. The pattern speed is a crucial parameter for constraining the internal dynamics, estimating the impact velocities of the gravitational perturbation at the resonance radii, and to set up an evolutionary scenario for NGC 6946. Our data allows us to derive the best fitting kinematic position angle and the geometry of the underlying gaseous disk, which we use to derive the pattern speed using the Tremaine-Weinberg method. We find a main pattern speed Omega_p=22 km/s/kpc, but our data clearly reveal the presence of an additional pattern speed Omega_p=47 km/s/kpc in a zone within 1.25 kpc of the nucleus. Using the epicyclic approximation, we deduce the location of the resonance radii and confirm that inside the outer Inner Lindblad Resonance radius of the main oval, a primary bar has formed rotating at more than twice the outer p...

  14. Quantifying Resonant Structure in NGC 6946 from Two-dimensional Kinematics

    E-Print Network [OSTI]

    Kambiz Fathi; Silvia Toonen; Jesśs Falcón-Barroso; John E. Beckman; Olivier Hernandez; Olivier Daigle; Claude Carignan; Tim de Zeeuw

    2007-08-08

    We study the two-dimensional kinematics of the H-alpha-emitting gas in the nearby barred Scd galaxy, NGC 6946, in order to determine the pattern speed of the primary m=2 perturbation mode. The pattern speed is a crucial parameter for constraining the internal dynamics, estimating the impact velocities of the gravitational perturbation at the resonance radii, and to set up an evolutionary scenario for NGC 6946. Our data allows us to derive the best fitting kinematic position angle and the geometry of the underlying gaseous disk, which we use to derive the pattern speed using the Tremaine-Weinberg method. We find a main pattern speed Omega_p=22 km/s/kpc, but our data clearly reveal the presence of an additional pattern speed Omega_p=47 km/s/kpc in a zone within 1.25 kpc of the nucleus. Using the epicyclic approximation, we deduce the location of the resonance radii and confirm that inside the outer Inner Lindblad Resonance radius of the main oval, a primary bar has formed rotating at more than twice the outer pattern speed. We further confirm that a nuclear bar has formed inside the Inner Lindblad Resonance radius of the primary bar, coinciding with the inner Inner Lindblad Resonance radius of the large-scale m=2 mode oval.

  15. Natural abundance 17O DNP two-dimensional and surface-enhanced NMR spectroscopy

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

    Perras, Frédéric A.; Kobayashi, Takeshi; Pruski, Marek

    2015-06-22

    Due to its extremely low natural abundance and quadrupolar nature, the 17O nuclide is very rarely used for spectroscopic investigation of solids by NMR without isotope enrichment. Additionally, the applicability of dynamic nuclear polarization (DNP), which leads to sensitivity enhancements of 2 orders of magnitude, to 17O is wrought with challenges due to the lack of spin diffusion and low polarization transfer efficiency from 1H. Here, we demonstrate new DNP-based measurements that extend 17O solid-state NMR beyond its current capabilities. The use of the PRESTO technique instead of conventional 1H–17O cross-polarization greatly improves the sensitivity and enables the facile measurementmore »of undistorted line shapes and two-dimensional 1H–17O HETCOR NMR spectra as well as accurate internuclear distance measurements at natural abundance. This was applied for distinguishing hydrogen-bonded and lone 17O sites on the surface of silica gel; the one-dimensional spectrum of which could not be used to extract such detail. As a result, this greatly enhanced sensitivity has enabled, for the first time, the detection of surface hydroxyl sites on mesoporous silica at natural abundance, thereby extending the concept of DNP surface-enhanced NMR spectroscopy to the 17O nuclide.« less

  16. Hollow cathode theory and experiment. II. A two-dimensional theoretical model of the emitter region

    SciTech Connect (OSTI)

    Mikellides, Ioannis G.; Katz, Ira; Goebel, Dan M.; Polk, James E.

    2005-12-01

    Despite their long history and wide range of applicability that includes electric propulsion, detailed understanding of the driving physics inside orificed hollow cathodes remains elusive. The theoretical complexity associated with the multicomponent fluid inside the cathode, and the difficulty of accessing empirically this region, have limited our ability to design cathodes that perform better and last longer. A two-dimensional axisymmetric theoretical model of the multispecies fluid inside an orificed hollow cathode is presented. The level of detail attained by the model is allowed by its extended system of governing equations not solved for in the past within the hollow cathode. Such detail is motivated in part by the need to quantify the effect(s) of the plasma on the emitter life, and by the need to build the foundation for future modeling that will assess erosion of the keeper plate. Results from numerical simulations of a 1.2-cm-diam cathode operating at a discharge current of 25 A and a gas flow rate of 5 SCCM show that approximately 10 A of electron current, and 3.45 A of ion current return back to the emitter surface. The total emitted electron current is 33.8 A and the peak emitter temperature is found to be 1440 K. Comparisons with the measurements suggest that anomalous heating of the plasma is possible near the orifice region. The model predicts heavy species temperatures as high as 2034 K and peak voltage drops near the emitting surface not exceeding 8 V.

  17. Ultrafast Photo-Induced Charge Transfer Unveiled by Two-Dimensional Electronic Spectroscopy

    E-Print Network [OSTI]

    Bixner, Oliver; Mancal, Tomas; Hauer, Juergen; Milota, Franz; Fischer, Michael; Pugliesi, Igor; Bradler, Maximilian; Schmid, Walther; Riedle, Eberhard; Kauffmann, Harald F; Christensson, Niklas

    2012-01-01

    The interaction of exciton and charge transfer (CT) states plays a central role in photo-induced CT processes in chemistry, biology and physics. In this work, we use a combination of two-dimensional electronic spectroscopy (2D-ES), pump-probe measurements and quantum chemistry to investigate the ultrafast CT dynamics in a lutetium bisphthalocyanine dimer in different oxidation states. It is found that in the anionic form, the combination of strong CT-exciton interaction and electronic asymmetry induced by a counter-ion enables CT between the two macrocycles of the complex on a 30 fs timescale. Following optical excitation, a chain of electron and hole transfer steps gives rise to characteristic cross-peak dynamics in the electronic 2D spectra, and we monitor how the excited state charge density ultimately localizes on the macrocycle closest to the counter-ion within 100 fs. A comparison with the dynamics in the radical species further elucidates how CT states modulate the electronic structure and tune fs-reac...

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

    E-Print Network [OSTI]

    J. A. McLaughlin; A. W. Hood

    2007-12-11

    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.

  19. Two-dimensional Turbulence in Symmetric Binary-Fluid Mixtures: Coarsening Arrest by the Inverse Cascade

    E-Print Network [OSTI]

    Prasad Perlekar; Nairita Pal; Rahul Pandit

    2015-06-29

    We study two-dimensional (2D) binary-fluid turbulence by carrying out an extensive direct numerical simulation (DNS) of the forced, statistically steady turbulence in the coupled Cahn-Hilliard and Navier-Stokes equations. In the absence of any coupling, we choose parameters that lead (a) to spinodal decomposition and domain growth, which is characterized by the spatiotemporal evolution of the Cahn-Hilliard order parameter $\\phi$, and (b) the formation of an inverse-energy-cascade regime in the energy spectrum $E(k)$, in which energy cascades towards wave numbers $k$ that are smaller than the energy-injection scale $k_{inj}$ in the turbulent fluid. We show that the Cahn-Hilliard-Navier-Stokes coupling leads to an arrest of phase separation at a length scale $L_c$, which we evaluate from $S(k)$, the spectrum of the fluctuations of $\\phi$. We demonstrate that (a) $L_c \\sim L_H$, the Hinze scale that follows from balancing inertial and interfacial-tension forces, and (b) $L_c$ is independent, within error bars, of the diffusivity $D$. We elucidate how this coupling modifies $E(k)$ by blocking the inverse energy cascade at a wavenumber $k_c$, which we show is $\\simeq 2\\pi/L_c$. We compare our work with earlier studies of this problem.

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

    SciTech Connect (OSTI)

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

    2009-11-15

    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)

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

    DOE Patents [OSTI]

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

    1985-04-30

    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.

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

    DOE Patents [OSTI]

    Anderson, Herbert L. (Santa Fe, NM); Kinnison, W. Wayne (Los Alamos, NM); Lillberg, John W. (Los Alamos, NM)

    1987-01-01

    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 of 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.

  3. Robust Intrinsic Ferromagnetism and Half Semiconductivity in Stable Two-Dimensional Single-Layer Chromium Trihalides

    E-Print Network [OSTI]

    Zhang, Wei-Bing; Zhu, Peng; Lam, Chi-Hang

    2015-01-01

    Two-dimensional (2D) intrinsic ferromagnetic (FM) semiconductors are crucial to develop low-dimensional spintronic devices. Using density functional theory, we show that single-layer chromium trihalides (SLCTs) (CrX$_3$,X=F, Cl, Br and I) constitute a series of stable 2D intrinsic FM semiconductors. A free-standing SLCT can be easily exfoliated from the bulk crystal, due to a low cleavage energy and a high in-plane stiffness. Electronic structure calculations using the HSE06 functional indicate that both bulk and single-layer CrX$_3$ are half semiconductors with indirect band gaps. The valence bands and conduction bands are fully spin-polarized in the same spin direction. The energy gaps and absorption edges of CrBr$_3$ and CrI$_3$ are found to be in the visible frequency range, which implies possible opt-electronic applications. Furthermore, these 2D crystals are found to possess a large magnetic moment of 3$\\mu_B$ per formula unit and a sizable magnetic anisotropy energy. The magnetic exchange constants of ...

  4. Revealing the Preferred Interlayer Orientations and Stackings of Two-Dimensional Bilayer Gallium Selenide Crystals

    SciTech Connect (OSTI)

    Li, Xufan; Basile Carrasco, Leonardo A; Yoon, Mina; Ma, Cheng; Puretzky, Alexander A; Lee, Jaekwang; Idrobo Tapia, Juan Carlos; Chi, Miaofang; Rouleau, Christopher M; Geohegan, David B; Xiao, Kai

    2015-01-01

    Characterizing and controlling the interlayer orientations and stacking order of bilayer two-dimensional (2D) crystals and van der Waals (vdW) heterostructure is crucial to optimize their electrical and optoelectronic properties. The four polymorphs of layered gallium selenide (GaSe) that result from different layer stacking provide an ideal platform to study the stacking configurations in bilayer 2D crystals. Here, through a controllable vapor-phase deposition method we selectively grow bilayer GaSe crystals and investigate their two preferred 0 or 60 interlayer rotations. The commensurate stacking configurations (AA and AB-stacking) in as-grown 2D bilayer GaSe crystals are clearly observed at the atomic scale and the Ga-terminated edge structure are identified for the first time by using atomic-resolution scanning transmission electron microscopy (STEM). Theoretical analysis of the interlayer coupling energetics vs. interlayer rotation angle reveals that the experimentally-observed orientations are energetically preferred among the bilayer GaSe crystal polytypes. The combined experimental and theoretical characterization of the GaSe bilayers afforded by these growth studies provide a pathway to reveal the atomistic relationships in interlayer orientations responsible for the electronic and optical properties of bilayer 2D crystals and vdW heterostructures.

  5. Low-frequency Raman 'fingerprints' of two-dimensional metal dichalcogenide layer stacking configurations

    SciTech Connect (OSTI)

    Puretzky, Alexander A; Liang, Liangbo; Li, Xufan; Xiao, Kai; Wang, Kai; Mahjouri-Samani, Masoud; Basile, Leonardo; Idrobo Tapia, Juan Carlos; Sumpter, Bobby G; Meunier, Vincent; Geohegan, David B

    2015-01-01

    Stacked monolayers of two-dimensional (2D) materials present a new class of hybrid materials with tunable optoelectronic properties determined by their stacking orientation, order, and atomic registry. Atomic-resolution Z-contrast scanning transmission electron microscopy (AR-Z-STEM) and electron energy loss spectroscopy (EELS) can be used to determine the exact atomic registration between different layers, in few-layer 2D stacks, however fast optical characterization techniques are essential for rapid development of the field. Here, using two- and three-layer MoSe2 and WSe2 crystals synthesized by chemical vapor deposition we show that the generally unexplored low frequency (LF) Raman modes (< 50 cm-1) that originate from interlayer vibrations can serve as fingerprints to characterize not only the number of layers, but also their stacking configurations. Ab initio calculations and group theory analysis corroborate the experimental assignments determined by AR-Z-STEM and show that the calculated LF mode fingerprints are related to the 2D crystal symmetries.

  6. Two-dimensional Turbulence in Symmetric Binary-Fluid Mixtures: Coarsening Arrest by the Inverse Cascade

    E-Print Network [OSTI]

    Perlekar, Prasad; Pandit, Rahul

    2015-01-01

    We study two-dimensional (2D) binary-fluid turbulence by carrying out an extensive direct numerical simulation (DNS) of the forced, statistically steady turbulence in the coupled Cahn-Hilliard and Navier-Stokes equations. In the absence of any coupling, we choose parameters that lead (a) to spinodal decomposition and domain growth, which is characterized by the spatiotemporal evolution of the Cahn-Hilliard order parameter $\\phi$, and (b) the formation of an inverse-energy-cascade regime in the energy spectrum $E(k)$, in which energy cascades towards wave numbers $k$ that are smaller than the energy-injection scale $k_{inj}$ in the turbulent fluid. We show that the Cahn-Hilliard-Navier-Stokes coupling leads to an arrest of phase separation at a length scale $L_c$, which we evaluate from $S(k)$, the spectrum of the fluctuations of $\\phi$. We demonstrate that (a) $L_c \\sim L_H$, the Hinze scale that follows from balancing inertial and interfacial-tension forces, and (b) $L_c$ is independent, within error bars, o...

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

    SciTech Connect (OSTI)

    Gheisari, R.; Firoozabadi, M. M.; Mohammadi, H.

    2014-01-15

    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.

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

    SciTech Connect (OSTI)

    Pevey, R.E.

    1982-07-01

    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.

  9. Two-dimensional N=(2,2) super Yang-Mills theory on computer

    E-Print Network [OSTI]

    Hiroshi Suzuki

    2007-09-05

    We carry out preliminary numerical study of Sugino's lattice formulation \\cite{Sugino:2004qd,Sugino:2004qdf} of the two-dimensional $\\mathcal{N}=(2,2)$ super Yang-Mills theory (2d $\\mathcal{N}=(2,2)$ SYM) with the gauge group $\\SU(2)$. The effect of dynamical fermions is included by re-weighting a quenched ensemble by the pfaffian factor. It appears that the complex phase of the pfaffian due to lattice artifacts and flat directions of the classical potential are not problematic in Monte Carlo simulation. Various one-point supersymmetric Ward-Takahashi (WT) identities are examined for lattice spacings up to $a=0.5/g$ with the fixed physical lattice size $L=4.0/g$, where $g$ denotes the gauge coupling constant in two dimensions. WT identities implied by an exact fermionic symmetry of the formulation are confirmed in fair accuracy and, for most of these identities, the quantum effect of dynamical fermions is clearly observed. For WT identities expected only in the continuum limit, the results seem to be consistent with the behavior expected from supersymmetry, although we do not see clear distintion from the quenched simulation. We measure also the expectation values of renormalized gauge-invariant bi-linear operators of scalar fields.

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

    E-Print Network [OSTI]

    Alba Y. Ramos; Omar Osenda

    2015-03-27

    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.

  11. Strain-induced energy band gap opening in two-dimensional bilayered silicon film

    E-Print Network [OSTI]

    Ji, Zhonghang; Voon, Lok C Lew Yan; Zhuang, Yan

    2015-01-01

    This work presents a theoretical study of the structural and electronic properties of bilayered silicon films under in-plane biaxial strain/stress using density functional theory. Atomic structures of the two-dimensional silicon films are optimized by using both the local-density approximation and generalized gradient approximation. In the absence of strain/stress, five buckled hexagonal honeycomb structures of the bilayered silicon film have been obtained as local energy minima and their structural stability has been verified. These structures present a Dirac-cone shaped energy band diagram with zero energy band gaps. Applying tensile biaxial strain leads to a reduction of the buckling height. Atomically flat structures with zero bucking height have been observed when the AA-stacking structures are under a critical biaxial strain. Increase of the strain between 10.7% ~ 15.4% results in a band-gap opening with a maximum energy band gap opening of ~168.0 meV obtained when 14.3% strain is applied. Energy band d...

  12. Simple models for two-dimensional tunable colloidal crystals in rotating ac electric fields

    E-Print Network [OSTI]

    Nils Elsner; C. Patrick Royall; Brian Vincent; David RE Snoswell

    2009-04-18

    We compare the behavior of a new two-dimensional aqueous colloidal model system with a simple numerical treatment. To the first order the attractive interaction between the colloids induced by an in-plane rotating ac electric field is dipolar, while the charge stabilization leads to a shorter ranged, Yukawa-like repulsion. In the crystal-like 'rafts' formed at sufficient field strengths, we find quantitative agreement between experiment and Monte Carlo simulation, except in the case of strongly interacting systems, where the well depth of the effective potential exceeds 250 times the thermal energy. The 'lattice constant' of the crystal-like raft is located approximately at the minimum of the effective potential, resulting from the sum of the Yukawa and dipolar interactions.The experimental system has display applications, owing to the possibility of tuning the lattice spacing with the external electric field. Limitations in the applied field strength and relative range of the electrostatic interactions of the particles result in a reduction in tunable lattice spacing for small and large particles, respectively. The optimal particle size for maximizing the lattice spacing tunability was found to be around 1000 nm.

  13. Displacement fields of point defects in two-dimensional colloidal crystals

    E-Print Network [OSTI]

    Wolfgang Lechner; Elisabeth Schöll-Paschinger; Christoph Dellago

    2008-05-20

    Point defects such as interstitials, vacancies, and impurities in otherwise perfect crystals induce complex displacement fields that are of long-range nature. In the present paper we study numerically the response of a two-dimensional colloidal crystal on a triangular lattice to the introduction of an interstitial particle. While far from the defect position the resulting displacement field is accurately described by linear elasticity theory, lattice effects dominate in the vicinity of the defect. In comparing the results of particle based simulations with continuum theory, it is crucial to employ corresponding boundary conditions in both cases. For the periodic boundary condition used here, the equations of elasticity theory can be solved in a consistent way with the technique of Ewald summation familiar from the electrostatics of periodically replicated systems of charges and dipoles. Very good agreement of the displacement fields calculated in this way with those determined in particle simulations is observed for distances of more than about 10 lattice constants. Closer to the interstitial, strongly anisotropic displacement fields with exponential behavior can occur for certain defect configurations. Here we rationalize this behavior with a simple bead-spring that relates the exponential decay constant to the elastic constants of the crystal.

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

    SciTech Connect (OSTI)

    Liu, Y. L.; Chen, S. H.; Koh, W. S.; Ang, L. K.

    2014-04-15

    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.

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

    SciTech Connect (OSTI)

    Zavadil, Kevin Robert; Hickner, Michael A.; Gross, Matthew L.

    2011-03-01

    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.

  16. Two-step growth of two-dimensional WSe2/MoSe2 heterostructures

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

    Gong, Yongji; Lei, Sidong; Lou, Jun; Liu, Zheng; Vajtai, Robert; Zhou, Wu; Ajayan, Pullikel M.

    2015-08-03

    Two dimensional (2D) materials have attracted great attention due to their unique properties and atomic thickness. Although various 2D materials have been successfully synthesized with different optical and electrical properties, a strategy for fabricating 2D heterostructures must be developed in order to construct more complicated devices for practical applications. Here we demonstrate for the first time a two-step chemical vapor deposition (CVD) method for growing transition-metal dichalcogenide (TMD) heterostructures, where MoSe2 was synthesized first and followed by an epitaxial growth of WSe2 on the edge and on the top surface of MoSe2. Compared to previously reported one-step growth methods, thismore »two-step growth has the capability of spatial and size control of each 2D component, leading to much larger (up to 169 ?m) heterostructure size, and cross-contamination can be effectively minimized. Furthermore, this two-step growth produces well-defined 2H and 3R stacking in the WSe2/MoSe2 bilayer regions and much sharper in-plane interfaces than the previously reported MoSe2/WSe2 heterojunctions obtained from one-step growth methods. The resultant heterostructures with WSe2/MoSe2 bilayer and the exposed MoSe2 monolayer display rectification characteristics of a p-n junction, as revealed by optoelectronic tests, and an internal quantum efficiency of 91% when functioning as a photodetector. As a result, a photovoltaic effect without any external gates was observed, showing incident photon to converted electron (IPCE) efficiencies of approximately 0.12%, providing application potential in electronics and energy harvesting.« less

  17. Quantum fluctuations in the BCS-BEC crossover of two-dimensional Fermi gases

    E-Print Network [OSTI]

    Lianyi He; Haifeng Lv; Gaoqing Cao; Hui Hu; Xia-Ji Liu

    2015-08-14

    We present a theoretical study of the ground state of the BCS-BEC crossover in dilute two-dimensional Fermi gases. While the mean-field theory provides a simple and analytical equation of state, the pressure is equal to that of a noninteracting Fermi gas in the entire BCS-BEC crossover, which is not consistent with the features of a weakly interacting Bose condensate in the BEC limit and a weakly interacting Fermi liquid in the BCS limit. The inadequacy of the 2D mean-field theory indicates that the quantum fluctuations are much more pronounced than those in 3D. In this work, we show that the inclusion of the Gaussian quantum fluctuations naturally recovers the above features in both the BEC and the BCS limits. In the BEC limit, the missing logarithmic dependence on the boson chemical potential is recovered by the quantum fluctuations. Near the quantum phase transition from the vacuum to the BEC phase, we compare our equation of state with the known grand canonical equation of state of 2D Bose gases and determine the ratio of the composite boson scattering length $a_{\\rm B}$ to the fermion scattering length $a_{\\rm 2D}$. We find $a_{\\rm B}\\simeq 0.56 a_{\\rm 2D}$, in good agreement with the exact four-body calculation. We compare our equation of state in the BCS-BEC crossover with recent results from the quantum Monte Carlo simulations and the experimental measurements and find good agreements.

  18. Unveiling Surface Redox Charge Storage of Interacting Two-Dimensional Hetero-Nanosheets in Hierarchical Architectures

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

    Mahmood, Qasim; Bak, Seong-Min; Kim, Min G.; Yun, Sol; Yang, Xiao-Qing; Shin, Hyeon S.; Kim, Woo S.; Braun, Paul V.; Park, Ho S.

    2015-03-03

    Two-dimensional (2D) heteronanosheets are currently the focus of intense study due to the unique properties that emerge from the interplay between two low-dimensional nanomaterials with different properties. However, the properties and new phenomena based on the two 2D heteronanosheets interacting in a 3D hierarchical architecture have yet to be explored. Here, we unveil the surface redox charge storage mechanism of surface-exposed WS2 nanosheets assembled in a 3D hierarchical heterostructure using in situ synchrotron X-ray absorption and Raman spectroscopic methods. The surface dominating redox charge storage of WS2 is manifested in a highly reversible and ultrafast capacitive fashion due to themore »interaction of heteronanosheets and the 3D connectivity of the hierarchical structure. In contrast, compositionally identical 2D WS2 structures fail to provide a fast and high capacitance with different modes of lattice vibration. The distinctive surface capacitive behavior of 3D hierarchically structured heteronanosheets is associated with rapid proton accommodation into the in-plane W–S lattice (with the softening of the E2g bands), the reversible redox transition of the surface-exposed intralayers residing in the electrochemically active 1T phase of WS2 (with the reversible change in the interatomic distance and peak intensity of W–W bonds), and the change in the oxidation state during the proton insertion/deinsertion process. This proposed mechanism agrees with the dramatic improvement in the capacitive performance of the two heteronanosheets coupled in the hierarchical structure.« less

  19. Fast chemical reaction in two-dimensional Navier-Stokes flow: Initial regime

    E-Print Network [OSTI]

    Farid Ait-Chaalal; Michel S. Bourqui; Peter Bartello

    2012-04-05

    This paper studies an infinitely fast bimolecular chemical reaction in a two-dimensional bi-periodic Navier-Stokes flow. The reactants in stoichiometric quantities are initially segregated by infinite gradients. The focus is placed on the initial stage of the reaction characterized by a well-defined one dimensional material contact line between the reactants. Particular attention is given to the effect of the diffusion of the reactants. This study is an idealized framework for isentropic mixing in the lower stratosphere and is motivated by the need to better understand the effect of resolutionon stratospheric chemistry in Climate-Chemistry Models. Adopting a Lagrangian stretching theory approach, we relate theoretically the ensemble mean of the length of the contact line, of the gradients along it and of the modulus of the rate of decrease of the space averaged reactant concentrations (here called the chemical speed) to the joint statistics of the finite time Lyapunov exponent with two equivalent times. The inverse of the Lyapunov exponent measures the stretching time scale of a Lagrangian parcel on a chaotic orbit up to a finite time t, while the first equivalent time measures it in the recent past before t and the second equivalent time in the early part of the trajectory. We show that the chemical speed scales like the square root of the diffusion and that its time evolution is determined by rare large events in the finite time Lyapunov exponent distribution. The case of smooth initial gradients is also discussed. The theoretical results are tested with an ensemble of direct numerical simulations (DNS) using a pseudospectral model.

  20. A new look at the collapse of two-dimensional polymers

    E-Print Network [OSTI]

    Eric Vernier; Jesper Lykke Jacobsen; Hubert Saleur

    2015-09-05

    We study the collapse of two-dimensional polymers, via an O($n$) model on the square lattice that allows for dilution, bending rigidity and short-range monomer attractions. This model contains two candidates for the theta point, $\\Theta_{\\rm BN}$ and $\\Theta_{\\rm DS}$, both exactly solvable. The relative stability of these points, and the question of which one describes the `generic' theta point, have been the source of a long-standing debate. Moreover, the analytically predicted exponents of $\\Theta_{\\rm BN}$ have never been convincingly observed in numerical simulations. In the present paper, we shed a new light on this confusing situation. We show in particular that the continuum limit of $\\Theta_{\\rm BN}$ is an unusual conformal field theory, made in fact of a simple dense polymer decorated with {\\sl non-compact degrees of freedom}. This implies in particular that the critical exponents take continuous rather than discrete values, and that corrections to scaling lead to an unusual integral form. Furthermore, discrete states may emerge from the continuum, but the latter are only normalizable---and hence observable---for appropriate values of the model's parameters. We check these findings numerically. We also probe the non-compact degrees of freedom in various ways, and establish that they are related to fluctuations of the density of monomers. Finally, we construct a field theoretic model of the vicinity of $\\Theta_{\\rm BN}$ and examine the flow along the multicritical line between $\\Theta_{\\rm BN}$ and $\\Theta_{\\rm DS}$.

  1. Two-dimensional simulations of explosive eruptions of Kick-em Jenny and other submarine volcanos

    SciTech Connect (OSTI)

    Gisler, Galen R.; Weaver, R. P. (Robert P.); Mader, Charles L.; Gittings, M. L. (Michael L.)

    2004-01-01

    Kick-em Jenny, in the Eastern Caribbean, is a submerged volcanic cone that has erupted a dozen or more times since its discovery in 1939. The most likely hazard posed by this volcano is to shipping in the immediate vicinity (through volcanic missiles or loss-of-buoyancy), but it is of interest to estimate upper limits on tsunamis that might be produced by a catastrophic explosive eruption. To this end, we have performed two-dimensional simulations of such an event in a geometry resembling that of Kick-em Jenny with our SAGE adaptive mesh Eulerian multifluid compressible hydrocode. We use realistic equations of state for air, water, and basalt, and follow the event from the initial explosive eruption, through the generation of a transient water cavity and the propagation of waves away from the site. We find that even for extremely catastrophic explosive eruptions, tsunamis from Kick-em Jenny are unlikely to pose significant danger to nearby islands. For comparison, we have also performed simulations of explosive eruptions at the much larger shield volcano Vailuluu in the Samoan chain, where the greater energy available can produce a more impressive wave. In general, however, we conclude that explosive eruptions do not couple well to water waves. The waves that are produced from such events are turbulent and highly dissipative, and don't propagate well. This is consistent with what we have found previously in simulations of asteroid-impact generated tsunamis. Non-explosive events, however, such as landslides or gas hydrate releases, do couple well to waves, and our simulations of tsunamis generated by subaerial and sub-aqueous landslides demonstrate this.

  2. Electron-beam-induced domain poling in LiNbO3 for two-dimensional nonlinear frequency conversion

    E-Print Network [OSTI]

    Arie, Ady

    Electron-beam-induced domain poling in LiNbO3 for two-dimensional nonlinear frequency conversion to achieve noncollinear second-harmonic generation. The sample was fabricated using an electron-beam indirect electron-beam poling,1 electric-field poling,2 and high-voltage atomic force microscop AFM .3

  3. Surface acoustic wave propagation and inhomogeneities in low-density two-dimensional electron systems near the metalinsulator transition

    E-Print Network [OSTI]

    Eisenstein, Jim

    Surface acoustic wave propagation and inhomogeneities in low-density two-dimensional electron) in a low-density regime (!1010 cmK2 ) at zero magnetic field. The interaction of the surface acoustic wave systems; D. Metal­insulator transition; E. Surface acoustic waves The apparent metal­insulator transition

  4. Graphene Oxide: Surface Activity and Two-Dimensional By Franklin Kim, Laura J. Cote, and Jiaxing Huang*

    E-Print Network [OSTI]

    Huang, Jiaxing

    ) is a promising precursor for preparing graphene-based composites and electronics applications. Like graphene, GO-dimensional assemblies over large areas is discussed. Figure 1. a) Typical preparation of graphene oxide (GO). PristineGraphene Oxide: Surface Activity and Two-Dimensional Assembly By Franklin Kim, Laura J. Cote

  5. Thermoacoustic modeling and uncertainty analysis of two-dimensional conductive Jonghoon Bin, William S. Oates, and Kunihiko Taira

    E-Print Network [OSTI]

    Thermoacoustic modeling and uncertainty analysis of two-dimensional conductive membranes Jonghoon-dimensional model for thermoacoustic engines J. Acoust. Soc. Am. 111, 2076 (2002); 10.1121/1.1467675 [This article://scitation.aip.org/termsconditions. Downloaded to ] IP: 146.201.18.83 On: Fri, 13 Feb 2015 15:46:28 #12;Thermoacoustic modeling and uncertainty

  6. White Noise Path Integral Treatment of a Two-dimensional Dirac Oscillator in a Uniform Magnetic Field

    SciTech Connect (OSTI)

    Bastatas, Lyndon D.; Bornales, Jinky B.

    2008-06-18

    White noise path integral prescription is applied to solve the Dirac equation for a two-dimensional Dirac oscillator in a uniform magnetic field. The energy spectrum obtained agrees with the result obtained by Villalba and Maggiolo using the differential approach.

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

    E-Print Network [OSTI]

    Kenji Nakahira; Tsuyoshi Sasaki Usuda

    2015-01-26

    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.

  8. EJTP 5, No. 17 (2008) 114 Electronic Journal of Theoretical Physics A Two-dimensional Discrete Mapping with C

    E-Print Network [OSTI]

    Sprott, Julien Clinton

    2008-01-01

    to the logistic map. Bounded solutions exist for the H´enon map over a range of a and b values, and a portion introduces a two-dimensional, C discrete bounded map capable to generating "multi- fold" strange attractors sin x, and we study this model for all values of a and b. The essential motivation for this work

  9. EJTP 5, No. 17 (2008) 111124 Electronic Journal of Theoretical Physics A Two-dimensional Discrete Mapping with C

    E-Print Network [OSTI]

    Sprott, Julien Clinton

    2008-01-01

    to the logistic map. Bounded solutions exist for the H´enon map over a range of a and b values, and a portion introduces a two-dimensional, C discrete bounded map capable of generating "multi- fold" strange attractors sin x, and we study this model for all values of a and b. The essential motivation for this work

  10. Two-dimensional diagnostics of edge and divertor region of toroidal helical plasmas using a lithium beam probe

    E-Print Network [OSTI]

    A is injected. Light emission from the injected beam by electron impact ex- citation (LiI/670.8 nm) is collected the emission of the injected neutral lithium beam by electron impact excitation. It can probe plasmas fromTwo-dimensional diagnostics of edge and divertor region of toroidal helical plasmas using a lithium

  11. Two-dimensional electron gas in a linearly varying magnetic field: Quantization of the electron and current density

    E-Print Network [OSTI]

    MacKinnon, Angus

    Two-dimensional electron gas in a linearly varying magnetic field: Quantization of the electron of electron and current densities. We investigate the case where the magnetic field varies linearly properties of a noninteracting electron gas in a linearly varying magnetic field, we consider the following

  12. Freezing transitions and the density of states of two-dimensional random Dirac Hamiltonians Baruch Horovitz1

    E-Print Network [OSTI]

    Horovitz, Baruch

    Freezing transitions and the density of states of two-dimensional random Dirac Hamiltonians Baruch dimensions that allows us to treat nonperturbative freezing phenomena. For purely random gauge disorder in the context of random gauge XY models12­18 and in particular the freezing transitions that occur

  13. Biologically-Inspired Self-Assembly of Two-Dimensional Shapes Using Global-to-Local Compilation

    E-Print Network [OSTI]

    Batzoglou, Serafim

    Biologically-Inspired Self-Assembly of Two-Dimensional Shapes Using Global-to-Local Compilation by decentralized, identically- programmed agents. Our system compiles a prede- termined global shape into a program. In the global- to-local compilation phase, an input shape is de- composed into a network of covering

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

    E-Print Network [OSTI]

    Baba, Toshihiko

    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

  15. Integrated digital inverters based on two-dimensional anisotropic ReS2 field-effect transistors

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

    Liu, Erfu; Fu, Yajun; Wang, Yaojia; Feng, Yanqing; Liu, Huimei; Wan, Xiangang; Zhou, Wei; Wang, Baigeng; Shao, Lubin; Ho, Ching-Hwa; et al

    2015-05-07

    Semiconducting two-dimensional transition metal dichalcogenides are emerging as top candidates for post-silicon electronics. While most of them exhibit isotropic behaviour, lowering the lattice symmetry could induce anisotropic properties, which are both scientifically interesting and potentially useful. Here we present atomically thin rhenium disulfide (ReS2) flakes with unique distorted 1T structure, which exhibit in-plane anisotropic properties. We fabricated monolayer and few-layer ReS2 field-effect transistors, which exhibit competitive performance with large current on/off ratios (~107) and low subthreshold swings (100 mV per decade). The observed anisotropic ratio along two principle axes reaches 3.1, which is the highest among all known two-dimensional semiconductingmore »materials. Furthermore, we successfully demonstrated an integrated digital inverter with good performance by utilizing two ReS2 anisotropic field-effect transistors, suggesting the promising implementation of large-scale two-dimensional logic circuits. Our results underscore the unique properties of two-dimensional semiconducting materials with low crystal symmetry for future electronic applications.« less

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

    E-Print Network [OSTI]

    V. M. Villalba; R. Pino

    2001-01-23

    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.

  17. Stability Studies of Two-dimensional Magnetic Bernstein-Greene-Kruskal Modes using Particle-in-Cell Simulations

    E-Print Network [OSTI]

    Ng, Chung-Sang

    Stability Studies of Two-dimensional Magnetic Bernstein-Greene-Kruskal Modes using Particle theoretical description of some of these structures is the concept of Bernstein-Greene-Kruskal (BGK) modes of their properties, including its energy content, temperature and velocity distribution, and stability. This work

  18. Strain and electric field induced electronic properties of two-dimensional hybrid bilayers of transition-metal dichalcogenides

    E-Print Network [OSTI]

    Pandey, Ravi

    . VC 2014 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4892798] I. INTRODUCTION Two dimensional (2D the semiconductor-to-metal transition. Application of the external electric fields, on the other hand, shows- liation technique similar to one applied to graphene. The layered TMDs are the class of materials

  19. On the direct insulator-quantum Hall transition in two-dimensional electron systems in the vicinity of nanoscaled scatterers

    E-Print Network [OSTI]

    Liang, Chi-Te; Lin, Li-Hung; Chen, Kuang Yao; Lo, Shun-Tsung; Wang, Yi-Ting; Lo, Dong-Sheng; Kim, Gil-Ho; Chang, Yuan Huei; Ochiai, Yuichi; Aoki, Nobuyuki; Chen, Jeng Chung; Lin, Yiping; Huang, Chun Feng; Lin, Sheng-Di; Richie, David A

    2011-02-11

    , Nicholls JT, Frost JEF, Linfield EH, Pepper M, Ford CJB, Ritchie DA, Jones GAC, Kogan E, Kaveh M: Magnetic-field-induced insulator-quantum Hall-insulator transition in a disordered two- dimensional electron gas. J Phys Condens Matter 1994, 6:4763. 6...

  20. Sedimentation of an elliptical object in a two-dimensional foam I.T. Davies, S.J. Cox1

    E-Print Network [OSTI]

    Cox, Simon

    Sedimentation of an elliptical object in a two-dimensional foam I.T. Davies, S.J. Cox1 Institute of Mathematics and Physics, Aberystwyth University, Ceredigion SY23 3BZ, UK Abstract The sedimentation laterally. A larger, more eccentric, ellipse rotates more quickly. Key words: foam, ellipse, sedimentation 1

  1. June 15, 1999 / Vol. 24, No. 12 / OPTICS LETTERS 817 Two-dimensional colloidal crystal corrugated waveguides

    E-Print Network [OSTI]

    Avrutsky, Ivan

    June 15, 1999 / Vol. 24, No. 12 / OPTICS LETTERS 817 Two-dimensional colloidal crystal corrugated colloidal crystals. We report experimental studies of light coupling into and out of the waveguide structure colloidal crystals. Self-assembly of colloid particles occurs on the surface of a planar waveguide

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

    E-Print Network [OSTI]

    Epstein, Irving R.

    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 with rotational symmetry in systems with circular geometry. We also find standing waves consisting of periodic

  3. Integration of one-and two-dimensional motion signals in infants: Evidence from the barber-pole illusion

    E-Print Network [OSTI]

    Dobkins, Karen R.

    Integration of one- and two-dimensional motion signals in infants: Evidence from the barber-pole into a coherent global motion percept by studying the ``barber-pole illusion''; when a one-dimensional moving study, we used barber-pole stimuli to investigate the develop- ment of motion mechanisms that integrate

  4. Seismic sources

    DOE Patents [OSTI]

    Green, M.A.; Cook, N.G.W.; McEvilly, T.V.; Majer, E.L.; Witherspoon, P.A.

    1987-04-20

    Apparatus is described for placement in a borehole in the earth, which enables the generation of closely controlled seismic waves from the borehole. Pure torsional shear waves are generated by an apparatus which includes a stator element fixed to the borehole walls and a rotor element which is electrically driven to rapidly oscillate on the stator element to cause reaction forces transmitted through the borehole walls to the surrounding earth. Longitudinal shear waves are generated by an armature that is driven to rapidly oscillate along the axis of the borehole, to cause reaction forces transmitted to the surrounding earth. Pressure waves are generated by electrically driving pistons that press against opposite ends of a hydraulic reservoir that fills the borehole. High power is generated by energizing the elements for more than about one minute. 9 figs.

  5. Seismic anisotropy in exploration and reservoir characterization: An overview

    E-Print Network [OSTI]

    Tsvankin, Ilya

    range of seismic methods. In particular, vertical and tilted transverse isotropy are currently treated vertical-seis- mic-profiling VSP surveys, moveout inversion of wide-azi- muth data, amplitudeSeismic anisotropy in exploration and reservoir characterization: An overview Ilya Tsvankin1

  6. 1) Plan of Work: United States Geological Survey Seismic Imaging Study in the Cities of Reno and Sparks, Nevada, June 2009

    E-Print Network [OSTI]

    . Acquisition along the Truckee River Path will extend west from Rock Blvd., run along #12;2 Mill St. between. Survey work, during daylight hours only, will extend along the River west from Rock Blvd., through traffic. The truck-mounted vibrator will creep about 1 mile per day along the River path, street parking

  7. Stochastic inversion of seismic PP and PS data for reservoir parameter estimation

    E-Print Network [OSTI]

    Chen, Jinsong

    surveying has been used for hydrocarbon exploration for decades because it can capture the seismic wavefieldStochastic inversion of seismic PP and PS data for reservoir parameter estimation Jinsong Chen1 and Michael E. Glinsky2 ABSTRACT We have investigated the value of isotropic seismic con- verted-wave (i

  8. SPECTRAL DECOMPOSITION APPLIED TO TIME-LAPSE SEISMIC INTERPRETATION AT RULISON FIELD,

    E-Print Network [OSTI]

    SPECTRAL DECOMPOSITION APPLIED TO TIME-LAPSE SEISMIC INTERPRETATION AT RULISON FIELD, GARFIELD focuses on the application of this technique to time-lapse seismic interpretation using nine-component 4D-lapse interpretation through a cross equalization process. I analyzed two time-lapse pairs of seismic surveys: 2003

  9. Monitoring of SAGD Process: Seismic Interpretation of Ray+Born Synthetic 4D Data

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Monitoring of SAGD Process: Seismic Interpretation of Ray+Born Synthetic 4D Data C. Joseph1, G ­ Monitoring of SAGD Process: Seismic Interpretation of Ray+Born Synthetic 4D Data ­ The objective of this study is to evaluate which production information can be deduced from a 4D seismic survey during

  10. DYNAMIC RESERVOIR CHARACTERIZATION USING P-WAVE SEISMIC TIME-LAPSE AT POSTLE FIELD,

    E-Print Network [OSTI]

    DYNAMIC RESERVOIR CHARACTERIZATION USING P-WAVE SEISMIC TIME-LAPSE AT POSTLE FIELD, TEXAS COUNTY characterize the reservoir at Postle Field. RCP shot a 6.25 square miles 4D, 9C seismic survey in March 2008.3 to 0.15. Quadrature attribute and seismic inversion-of-difference provide qualitative and quantitative

  11. Time lapse seismic signal analysis for Cranfield, MS, EOR and CCS site Ditkof, J.1

    E-Print Network [OSTI]

    Texas at Austin, University of

    of CO2 remain in the subsurface. In 2007 and 2010, 3D seismic surveys were shot and an initial 4D seismic response was characterized showing coherent amplitude anomalies in some areas which received large and acoustic impedance change through the reservoir. The two seismic volumes were cross

  12. A two-dimensional matrix correction for off-axis portal dose prediction errors

    SciTech Connect (OSTI)

    Bailey, Daniel W.; Kumaraswamy, Lalith; Bakhtiari, Mohammad; Podgorsak, Matthew B.

    2013-05-15

    Purpose: This study presents a follow-up to a modified calibration procedure for portal dosimetry published by Bailey et al. ['An effective correction algorithm for off-axis portal dosimetry errors,' Med. Phys. 36, 4089-4094 (2009)]. A commercial portal dose prediction system exhibits disagreement of up to 15% (calibrated units) between measured and predicted images as off-axis distance increases. The previous modified calibration procedure accounts for these off-axis effects in most regions of the detecting surface, but is limited by the simplistic assumption of radial symmetry. Methods: We find that a two-dimensional (2D) matrix correction, applied to each calibrated image, accounts for off-axis prediction errors in all regions of the detecting surface, including those still problematic after the radial correction is performed. The correction matrix is calculated by quantitative comparison of predicted and measured images that span the entire detecting surface. The correction matrix was verified for dose-linearity, and its effectiveness was verified on a number of test fields. The 2D correction was employed to retrospectively examine 22 off-axis, asymmetric electronic-compensation breast fields, five intensity-modulated brain fields (moderate-high modulation) manipulated for far off-axis delivery, and 29 intensity-modulated clinical fields of varying complexity in the central portion of the detecting surface. Results: Employing the matrix correction to the off-axis test fields and clinical fields, predicted vs measured portal dose agreement improves by up to 15%, producing up to 10% better agreement than the radial correction in some areas of the detecting surface. Gamma evaluation analyses (3 mm, 3% global, 10% dose threshold) of predicted vs measured portal dose images demonstrate pass rate improvement of up to 75% with the matrix correction, producing pass rates that are up to 30% higher than those resulting from the radial correction technique alone. As in the 1D correction case, the 2D algorithm leaves the portal dosimetry process virtually unchanged in the central portion of the detector, and thus these correction algorithms are not needed for centrally located fields of moderate size (at least, in the case of 6 MV beam energy).Conclusion: The 2D correction improves the portal dosimetry results for those fields for which the 1D correction proves insufficient, especially in the inplane, off-axis regions of the detector. This 2D correction neglects the relatively smaller discrepancies that may be caused by backscatter from nonuniform machine components downstream from the detecting layer.

  13. An Experimental Study of Critical Heat Flux in Narrow Gap With Two-Dimensional Slices

    SciTech Connect (OSTI)

    Yong Hoon Kim; Suh, Kune Y. [Seoul National University, San56-1 Shinrim-dong, Gwanak-gu, Seoul, 151-742 (Korea, Republic of); Rae Joon Park; San Baek Kim; Hee Dong Kim [Korea Atomic Energy Research Institute, 150, Dukjin-Dong, Yusong-Gu, Taejon 305-353 (Korea, Republic of)

    2002-07-01

    A cooling mechanism due to boiling in a gap between the debris crust and the reactor pressure vessel (RPV) wall was proposed for the TMI-2 reactor accident analysis. If there is enough heat transfer through the gap to cool the outer surface of the debris and the inner surface of the wall, the RPV wall may preserve its integrity during a severe core melt accident. If the heat removal through gap cooling relative to the counter-current flow limitation (CCFL) is pronounced, the safety margin of the reactor can be far greater than what had been previously known in the severe accident management arena. Should a severe accident take place, the RPV integrity will be maintained because of the inherent nature of degraded core coolability inside the lower head due to boiling in a narrow gap between the debris crust and the RPV wall. As a defense-in-depth measure, the heat removal capability by gap cooling coupled with external cooling can be examined for the Korean Standard Nuclear Power Plant (KSNPP) and the Advanced Power Reactor 1400 MWe (APR1400) in light of the TMI-2 vessel survival. A number of studies were carried out to investigate the complex heat transfer mechanisms for the debris cooling in the lower plenum. However, these heat transfer mechanisms have not been clearly understood yet. The CHFG (Critical Heat Flux in Gap) experiments at KAERI were carried out to develop the critical heat flux (CHF) correlation in a hemispherical gap, which is the upper limit of the heat transfer. According to the CHFG experiments performed with a pool boiling condition, the CHF in a parallel gap was reduced by 1/30 compared with the value measured in the open pool boiling condition. The correlation developed from the CHFG experiment is based on the fact that the CHF in a hemispherical gap is governed by the CCFL and a Kutateladze type CCFL parameter correlates CCFL data well in hemispherical gap geometry. However, the results of the CHFG experiments appear to be limited in their value because the power of the heaters was restricted by the three-dimensional (3D) geometry. The two-dimensional (2D) geometry relative to the 3D geometry enables the heaters to produce higher power. Experiments were conducted to develop the CHF correlation for gap cooling with the 2D slices. The experimental facility consisted of a heater, a pressure vessel, a heat exchanger and the pressure and temperature measurement system. Tests were carried out in the pressure range of 0.1 to 1 MPa for the gap sizes of 1 mm and 2 mm using demineralized water. (authors)

  14. Two-Dimensional Coordination Polymers with One-Dimensional Magnetic Chains: Hydrothermal Synthesis, Crystal Structure, and Magnetic and Thermal Properties of

    E-Print Network [OSTI]

    Li, Jing

    commonly employed in the synthesis of numerous solid-state inorganic materials. ComparablyTwo-Dimensional Coordination Polymers with One-Dimensional Magnetic Chains: Hydrothermal Synthesis

  15. Seismic sources

    DOE Patents [OSTI]

    Green, Michael A. (Oakland, CA); Cook, Neville G. W. (Lafayette, CA); McEvilly, Thomas V. (Berkeley, CA); Majer, Ernest L. (El Cirrito, CA); Witherspoon, Paul A. (Berkeley, CA)

    1992-01-01

    Apparatus is described for placement in a borehole in the earth, which enables the generation of closely controlled seismic waves from the borehole. Pure torsional shear waves are generated by an apparatus which includes a stator element fixed to the borehole walls and a rotor element which is electrically driven to rapidly oscillate on the stator element to cause reaction forces transmitted through the borehole walls to the surrounding earth. Logitudinal shear waves are generated by an armature that is driven to rapidly oscillate along the axis of the borehole relative to a stator that is clamped to the borehole, to cause reaction forces transmitted to the surrounding earth. Pressure waves are generated by electrically driving pistons that press against opposite ends of a hydraulic reservoir that fills the borehole. High power is generated by energizing the elements at a power level that causes heating to over 150.degree. C. within one minute of operation, but energizing the elements for no more than about one minute.

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

    E-Print Network [OSTI]

    Abdelmalek Boumali

    2014-10-10

    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.

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

    DOE Patents [OSTI]

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

    2007-01-30

    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.

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

    SciTech Connect (OSTI)

    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)

    2014-09-01

    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.

  19. SEISMIC ENGINEERING RESEARCH INFRASTRUCTURES FOR EUROPEAN SYNERGIES

    E-Print Network [OSTI]

    SERIES SEISMIC ENGINEERING RESEARCH INFRASTRUCTURES FOR EUROPEAN SYNERGIES COMMISSION;SEISMIC ENGINEERING RESEARCH INFRASTRUCTURES FOR EUROPEAN SYNERGIES LNEC/NESDE Main activities · Seismic action characterization studies, seismic hazard and seismic risk · Seismic assessment of structures

  20. SEISMIC RAY THEORY Seismic Ray Theory presents the most comprehensive treatment of the seismic

    E-Print Network [OSTI]

    Cerveny, Vlastislav

    #12;SEISMIC RAY THEORY Seismic Ray Theory presents the most comprehensive treatment of the seismic ray method available. This method plays an important role in seismology, seismic exploration, and the interpretation of seismic measurements. The book presents a consistent treatment of the seismic ray method, based

  1. Seismic velocity estimation from time migration

    E-Print Network [OSTI]

    Cameron, Maria Kourkina

    2007-01-01

    Seismic images . . . . . . . . . . . . . . . . .Algorithms producing the seismic velocities from thethe Dix velocities and the true seismic velocities in 2D . .

  2. Seismic Performance Assessment in Dense Urban Environments

    E-Print Network [OSTI]

    Mason, Henry Benjamin

    2011-01-01

    Kinematic interaction . . 4.4.2 Seismic footing response 6Deterministic seismic hazard analysis . . . . . . . . . .Probabilistic seismic hazard analysis . . . . . . . . .

  3. Crystal structures of two-dimensional magnetic colloids in tilted external magnetic fields V. A. Froltsov, R. Blaak, C. N. Likos, and H. Lowen

    E-Print Network [OSTI]

    Likos, Christos N.

    Crystal structures of two-dimensional magnetic colloids in tilted external magnetic fields V. A; published 30 December 2003 The stability of different crystal lattices of two-dimensional superparamagnetic suspensions that are confined to a planar liquid-gas interface and exposed to a tilted external magnetic field

  4. Simulation of a two-dimensional sheath over a flat insulatorconductor interface on a radio-frequency biased electrode in a high-density plasma

    E-Print Network [OSTI]

    Economou, Demetre J.

    Simulation of a two-dimensional sheath over a flat insulator­conductor interface on a radio-frequency the two-dimensional 2D sheath over a flat insulator/conductor interface on a radio-frequency rf biased is no longer one dimen- sional. The extent of sheath ``disturbance'' depends on the thickness of the sheath

  5. Anisotropic mean-square displacements in two-dimensional colloidal crystals of tilted dipoles V. A. Froltsov, C. N. Likos, and H. Lwen

    E-Print Network [OSTI]

    Likos, Christos N.

    Anisotropic mean-square displacements in two-dimensional colloidal crystals of tilted dipoles V. A the crystal aniso- tropy or not. Here we study an anisotropic two-dimensional colloidal crystal composed; revised manuscript received 7 February 2005; published 31 March 2005 Superparamagnetic colloidal particles

  6. Lorentz contraction of the equal-time Bethe-Salpeter amplitude in two-dimensional massless quantum electrodynamics

    E-Print Network [OSTI]

    Radozycki, Tomasz

    2015-01-01

    The Lorentz transformation properties of the equal-time bound-state Bethe-Salpeter amplitude in the two-dimensional massless quantum electrodynamics (the so called Schwinger Model) are considered. It is shown that while boosting a bound state (a `meson') this amplitude is subject to approximate Lorentz contraction. The effect is exact for large separations of constituent particles (`quarks'), while for small distances the deviation is more significant. For this phenomenon to appear, the full} function, i.e. with the inclusion of all instanton contributions has to be considered. The amplitude in each separate topological sector does not exhibit such properties.

  7. Lorentz contraction of the equal-time Bethe-Salpeter amplitude in two-dimensional massless quantum electrodynamics

    E-Print Network [OSTI]

    Tomasz Radozycki

    2015-08-31

    The Lorentz transformation properties of the equal-time bound-state Bethe-Salpeter amplitude in the two-dimensional massless quantum electrodynamics (the so called Schwinger Model) are considered. It is shown that while boosting a bound state (a `meson') this amplitude is subject to approximate Lorentz contraction. The effect is exact for large separations of constituent particles (`quarks'), while for small distances the deviation is more significant. For this phenomenon to appear, the full} function, i.e. with the inclusion of all instanton contributions has to be considered. The amplitude in each separate topological sector does not exhibit such properties.

  8. Large-$q$ expansion of the specific heat for the two-dimensional $q$-state Potts model

    E-Print Network [OSTI]

    H. Arisue; K. Tabata

    1998-07-03

    We have calculated the large-$q$ expansion for the specific heat at the phase transition point in the two-dimensional $q$-state Potts model to the 23rd order in $1/\\sqrt{q}$ using the finite lattice method. The obtained series allows us to give highly convergent estimates of the specific heat for $q>4$ on the first order transition point. The result confirm us the correctness of the conjecture by Bhattacharya et al. on the asymptotic behavior of the specific heat for $q \\to 4_+$.

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

    E-Print Network [OSTI]

    Vishwanath Shukla; Marc Brachet; Rahul Pandit

    2014-11-23

    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.

  10. Insulating state to quantum Hall-like state transition in a spin-orbit-coupled two-dimensional electron system

    SciTech Connect (OSTI)

    Lo, Shun-Tsung; Hsu, Chang-Shun [Graduate Institute of Applied Physics, National Taiwan University, Taipei 10617, Taiwan (China); Lin, Y. M.; Lin, S.-D.; Lee, C. P. [Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Ho, Sheng-Han; Chuang, Chiashain; Wang, Yi-Ting [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Liang, C.-T. [Graduate Institute of Applied Physics, National Taiwan University, Taipei 10617, Taiwan (China); Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China)

    2014-07-07

    We study interference and interactions in an InAs/InAsSb two-dimensional electron system. In such a system, spin-orbit interactions are shown to be strong, which result in weak antilocalization (WAL) and thereby positive magnetoresistance around zero magnetic field. After suppressing WAL by the magnetic field, we demonstrate that classical positive magnetoresistance due to spin-orbit coupling plays a role. With further increasing the magnetic field, the system undergoes a direct insulator-quantum Hall transition. By analyzing the magnetotransport behavior in different field regions, we show that both electron-electron interactions and spin-related effects are essential in understanding the observed direct transition.

  11. A Fast Algorithm for Eye Detection Using Two-Dimensional CSP Akiko SUZUKI Tetsuya TAKIGUCHI Yasuo ARIKI

    E-Print Network [OSTI]

    Takiguchi, Tetsuya

    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 × H I(x, y) w × 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

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

    E-Print Network [OSTI]

    Hill, James Robert

    1981-01-01

    (December 1981) James Robert Hill B. S. , The Ohio State University Chairman of Advisory Committee: Dr. David R. Basco The depth averaged conservation form of the equations of motion is used to develop a two-dimensional numerical model. This particular... models in ex1stence, many schemes are very similar in the fin1te-d1fference methodology as well as the grid structure. Realizing th1s fact, the study of a representative cross section of exist1ng models seems suff'icient to gain some ins1ght into two...

  13. Reflection Survey At Neal Hot Springs Geothermal Area (Colwell...

    Open Energy Info (EERE)

    Activity Date 2011 - 2011 Usefulness useful DOE-funding Unknown Exploration Basis Seismic surveys ware conducted to gain a better understanding of the geology and structure of...

  14. Seismic technology will be of key importance for evaluat-ing gas-hydrate resources, particularly across the Gulf of

    E-Print Network [OSTI]

    Texas at Austin, University of

    Seismic technology will be of key importance for evaluat- ing gas-hydrate resources, particularly across the Gulf of Mexico (GoM) where many seismic surveys have been acquired and will continue to be acquired. To apply seismic technology to gas-hydrate studies in the gulf in an optimal manner

  15. Short-Period Seismic Noise in Vorkuta (Russia)

    SciTech Connect (OSTI)

    Kishkina, S B; Spivak, A A; Sweeney, J J

    2008-05-15

    Cultural development of new subpolar areas of Russia is associated with a need for detailed seismic research, including both mapping of regional seismicity and seismic monitoring of specific mining enterprises. Of special interest are the northern territories of European Russia, including shelves of the Kara and Barents Seas, Yamal Peninsula, and the Timan-Pechora region. Continuous seismic studies of these territories are important now because there is insufficient seismological knowledge of the area and an absence of systematic data on the seismicity of the region. Another task of current interest is the necessity to consider the seismic environment in the design, construction, and operation of natural gas extracting enterprises such as the construction of the North European Gas Pipeline. Issues of scientific importance for seismic studies in the region are the complex geodynamical setting, the presence of permafrost, and the complex tectonic structure. In particular, the Uralian Orogene (Fig. 1) strongly affects the propagation of seismic waves. The existing subpolar seismic stations [APA (67,57{sup o}N; 33,40{sup o}E), LVZ (67,90{sup o}N; 34,65{sup o}E), and NRIL (69,50{sup o}N; 88,40{sup o}E)] do not cover the extensive area between the Pechora and Ob Rivers (Fig. 1). Thus seismic observations in the Vorkuta area, which lies within the area of concern, represent a special interest. Continuous recording at a seismic station near the city of Vorkuta (67,50{sup o}N; 64,11{sup o}E) [1] has been conducted since 2005 for the purpose of regional seismic monitoring and, more specifically, detection of seismic signals caused by local mining enterprises. Current surveys of local seismic noise [7,8,9,11], are particularly aimed at a technical survey for the suitability of the site for installation of a small-aperture seismic array, which would include 10-12 recording instruments, with the Vorkuta seismic station as the central element. When constructed, this seismic array will considerably improve the recording capacity of regional and local seismic events. It will allow detection of signatures of seismic waves propagating in submeridional and sublatitudinal directions. The latter is of special interest not only to access the influence of the Urals on propagation patterns of seismic waves, but also to address other questions, such as the structure and dynamic characteristics of the internal dynamo of the Earth [9,13]. Recording seismic waves at low angular distances from seismically active subpolar zones will allow us to collect data on vortical and convective movements in subpolar lithosphere blocks and at the boundary of the inner core of the Earth, possibly giving essential clues to the modeling of the Earth's electromagnetic field [3,13]. The present study considers basic features of seismic noise at the Vorkuta station obtained through the analysis of seismic records from March, 2006 till December, 2007.

  16. Seismic Structure And Seismicity Of The Cooling Lava Lake Of...

    Open Energy Info (EERE)

    Seismic Structure And Seismicity Of The Cooling Lava Lake Of Kilauea Iki, Hawaii Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Seismic...

  17. Teleseismic-Seismic Monitoring At Central Nevada Seismic Zone...

    Open Energy Info (EERE)

    Teleseismic-Seismic Monitoring At Central Nevada Seismic Zone Region (Biasi, Et Al., 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity:...

  18. USING MICRO-SEISMICITY AND SEISMIC VELOCITIES TO MAP SUBSURFACE...

    Open Energy Info (EERE)

    USING MICRO-SEISMICITY AND SEISMIC VELOCITIES TO MAP SUBSURFACE GEOLOGIC AND HYDROLOGIC STRUCTURE WITHIN THE COSO GEOTHERMAL FIELD, CALIFORNIA Jump to: navigation, search OpenEI...

  19. Seismicity and seismic stress in the Coso Range, Coso geothermal...

    Open Energy Info (EERE)

    Seismicity and seismic stress in the Coso Range, Coso geothermal field, and Indian Wells Valley region, Southeast-Central California Jump to: navigation, search OpenEI Reference...

  20. Teleseismic-Seismic Monitoring At Central Nevada Seismic Zone...

    Open Energy Info (EERE)

    Teleseismic-Seismic Monitoring At Central Nevada Seismic Zone Region (Biasi, Et Al., 2008) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity:...

  1. Using Micro-Seismicity and Seismic Velocities to Map Subsurface...

    Open Energy Info (EERE)

    Using Micro-Seismicity and Seismic Velocities to Map Subsurface Geologic and Hydrologic Structure Within the Coso Geothermal Field California Jump to: navigation, search OpenEI...

  2. Seismic Design Expectations Report

    Office of Environmental Management (EM)

    flood, and lightning. This report only focuses on the seismic design expectations. NPH safety requirements are described in 10 CFR Part 830, Nuclear Safety Management, DOE O...

  3. Seismic Imaging and Monitoring

    SciTech Connect (OSTI)

    Huang, Lianjie

    2012-07-09

    I give an overview of LANL's capability in seismic imaging and monitoring. I present some seismic imaging and monitoring results, including imaging of complex structures, subsalt imaging of Gulf of Mexico, fault/fracture zone imaging for geothermal exploration at the Jemez pueblo, time-lapse imaging of a walkway vertical seismic profiling data for monitoring CO{sub 2} inject at SACROC, and microseismic event locations for monitoring CO{sub 2} injection at Aneth. These examples demonstrate LANL's high-resolution and high-fidelity seismic imaging and monitoring capabilities.

  4. 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]

    Dutkiewicz, Stephanie.

    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 ...

  5. Omnidirectional wavelength selective emitters/absorbers based on dielectric-filled anti-reflection coated two-dimensional metallic photonic crystals

    E-Print Network [OSTI]

    Yeng, Yi Xiang

    We demonstrate designs of dielectric-filled anti-reflection coated (ARC) two-dimensional (2D) metallic photonic crystals (MPhCs) capable of omnidirectional, polarization insensitive, wavelength selective emission/absorption. ...

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

    E-Print Network [OSTI]

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

    2006-01-01

    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 ...

  7. Seismic mass Top electrode

    E-Print Network [OSTI]

    Kraft, Michael

    assembly process. For the measurements of the physical dimensions of the seismic mass a micrometer was usedSeismic mass Top electrode Bottom electrode x C1 C2 Chapter 4: The Micromachined Sensing Element supplied by Druck, Ltd., Groby, Leics. The manufacturing process at Druck was still in its experimental

  8. Two-dimensional resonant magnetic excitation in BaFe1.84Co0.16As2

    SciTech Connect (OSTI)

    Lumsden, Mark D; Christianson, Andrew D; Parshall, Daniel; Stone, Matthew B; Nagler, Stephen E; Mook Jr, Herbert A; Lokshin, Konstantin A; Egami, Takeshi; Abernathy, Douglas L; Goremychkin, E. A.; Osborn, R.; McGuire, Michael A; Safa-Sefat, Athena; Jin, Rongying; Sales, Brian C; Mandrus, David

    2009-01-01

    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.

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

    SciTech Connect (OSTI)

    Amoudache, Samira; Pennec, Yan Djafari Rouhani, Bahram; Khater, Antoine; Lucklum, Ralf; Tigrine, Rachid

    2014-04-07

    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.

  10. Development of a novel x-ray focusing technique using crystals with two-dimensionally modulated surfaces

    SciTech Connect (OSTI)

    Chang, W.Z.; Kley, E.B.; Fuchs, H.J.; Schnabel, B.; Foerster, E.; Chukhovskii, F.N.

    1995-12-31

    Theoretical investigations for obtaining x-ray point focusing by using crystals with two-dimensionally modulated surfaces are carried out. Based on the Bragg and Fresnel diffraction principles, formulae of modulated surfaces (structures) are derived for both flat and bent crystals for focusing x-rays to micron or submicron size. It is found that elliptically-shaped and linearly modulated structures are suitable for flat and cylindrically bent crystals, respectively. For the given Ti K{alpha} radiation and geometric parameters, Si(111) and InSb(111) reflections are used for the calculations of flat and bent crystals in terms of their focus characteristics, namely the focusing efficiency and the focus width. The influence of the distribution of the Bragg amplitude on flat and bent crystals is also discussed.

  11. Electron heating due to microwave photoexcitation in the high mobility GaAs/AlGaAs two dimensional electron system

    SciTech Connect (OSTI)

    Ramanayaka, A. N.; Mani, R. G.; Wegscheider, W.

    2013-12-04

    We extract the electron temperature in the microwave photo-excited high mobility GaAs/AlGaAs two dimensional electron system (2DES) by studying the influence of microwave radiation on the amplitude of Shubnikov-de Haas oscillations (SdHOs) in a regime where the cyclotron frequency, ?{sub c}, and the microwave angular frequency, ?, satisfy 2? ? ?{sub c} ? 3.5? The results indicate that increasing the incident microwave power has a weak effect on the amplitude of the SdHOs and therefore the electron temperature, in comparison to the influence of modest temperature changes on the dark-specimen SdH effect. The results indicate negligible electron heating under modest microwave photo-excitation, in good agreement with theoretical predictions.

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

    SciTech Connect (OSTI)

    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)

    2014-02-07

    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.

  13. A phase field approach for optimal boundary control of damage processes in two-dimensional viscoelastic media

    E-Print Network [OSTI]

    M. Hassan Farshbaf-Shaker; Christian Heinemann

    2015-07-08

    In this work we investigate a phase field model for damage processes in two-dimensional viscoelastic media with nonhomogeneous Neumann data describing external boundary forces. In the first part we establish global-in-time existence, uniqueness, a priori estimates and continuous dependence of strong solutions on the data. The main difficulty is caused by the irreversibility of the phase field variable which results in a constrained PDE system. In the last part we consider an optimal control problem where a cost functional penalizes maximal deviations from prescribed damage profiles. The goal is to minimize the cost functional with respect to exterior forces acting on the boundary which play the role of the control variable in the considered model. To this end, we prove existence of minimizers and study a family of "local" approximations via adapted cost functionals.

  14. Interaction of a two-dimensional electromagnetic breather with an electron inhomogeneity in an array of carbon nanotubes

    SciTech Connect (OSTI)

    Zhukov, Alexander V., E-mail: alex-zhukov@sutd.edu.sg; Bouffanais, Roland [Singapore University of Technology and Design, 20 Dover Drive, Singapore 138682 (Singapore); Fedorov, E. G. [Volgograd State University of Architecture and Civil Engineering, 400074 Volgograd (Russian Federation); Belonenko, Mikhail B. [Laboratory of Nanotechnology, Volgograd Institute of Business, 400048 Volgograd (Russian Federation)

    2014-05-28

    Propagation of ultrashort laser pulses through various nano-objects has recently became an attractive topic for both theoretical and experimental studies due to its promising perspectives in a variety of problems of modern nanoelectronics. Here, we study the propagation of extremely short two-dimensional bipolar electromagnetic pulses in a heterogeneous array of semiconductor carbon nanotubes. Heterogeneity is defined as a region of enhanced electron density. The electromagnetic field in an array of nanotubes is described by Maxwell's equations, reduced to a multidimensional wave equation. Our numerical analysis shows the possibility of stable propagation of an electromagnetic pulse in a heterogeneous array of nanotubes. Furthermore, we establish that, depending on its speed of propagation, the pulse can pass through the area of increased electron concentration or be reflected therefrom.

  15. TWO-DIMENSIONAL NUMERICAL STUDY FOR RAYLEIGH-TAYLOR AND RICHTMYER-MESHKOV INSTABILITIES IN RELATIVISTIC JETS

    SciTech Connect (OSTI)

    Matsumoto, Jin; Masada, Youhei

    2013-07-20

    We study the stability of a non-rotating single-component jet using two-dimensional special relativistic hydrodynamic simulations. By assuming translational invariance along the jet axis, we exclude the destabilization effect by Kelvin-Helmholtz mode. The nonlinear evolution of the transverse structure of the jet with a normal jet velocity is highlighted. An intriguing finding in our study is that Rayleigh-Taylor and Richtmyer-Meshkov type instabilities can destroy cylindrical jet configuration as a result of spontaneously induced radial oscillating motion. This is powered by in situ energy conversion between the thermal and bulk kinetic energies. The effective inertia ratio of the jet to the surrounding medium {eta} determines a threshold for the onset of instabilities. The condition {eta} < 1 should be satisfied for the transverse structure of the jet being persisted.

  16. The internal structure of a vortex in a two-dimensional superfluid with long healing length and its implications

    SciTech Connect (OSTI)

    Klein, Avraham; Aleiner, Igor L.; Agam, Oded

    2014-07-15

    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.

  17. Two-dimensional numerical study of two counter-propagating helium plasma jets in air at atmospheric pressure

    SciTech Connect (OSTI)

    Yan, Wen; Sang, Chaofeng; Wang, Dezhen; Liu, Fucheng

    2014-06-15

    In this paper, a computational study of two counter-propagating helium plasma jets in ambient air is presented. A two-dimensional fluid model is applied to investigate the physical processes of the two plasma jets interaction (PJI) driven by equal and unequal voltages, respectively. In all studied cases, the PJI results in a decrease of both plasma bullets propagation velocity. When the two plasma jets are driven by equal voltages, they never merge but rather approach each other around the middle of the gas gap at a minimum approach distance, and the minimal distance decreases with the increase of both the applied voltages and initial electron density, but increases with the increase of the relative permittivity. When the two plasma jets are driven by unequal voltages, we observe the two plasma jets will merge at the position away from the middle of the gas gap. The effect of applied voltage difference on the PJI is also studied.

  18. Turbulence structure of drag-reducing surfactant solution in two-dimensional channel with additional heat transfer enhancement method

    SciTech Connect (OSTI)

    Li, P.W.; Daisaka, H.; Kawaguchi, Y.; Yabe, A.; Hishida, K.; Maeda, M.

    1999-07-01

    The turbulent characteristics of a surfactant water solution in changing from drag-reducing flow to turbulent flow inside a two-dimensional smooth channel and in changing from turbulent flow to drag-reducing flow in the same channel with a mesh plug were investigated through LDV measurement in this study. The mesh plug was used to exert high shear stress to destroy micelle structures in the surfactant solution so that turbulence could be produced for better heat transfer. The two-component LDV system was installed on a movable platform, which could be moved streamwise of the flow to measure the two-dimensional velocity at different stations downstream from the mesh plug. The surfactant tested was Cetyltrimethyl ammonium chloride (C{sub 16}H{sub 33}N(CH{sub 3}){sub 3}Cl, abbreviated as CTAC). Local tap water was used as solvent and same weight concentration of sodium salicylate was used as the counter-ion material. The investigation of turbulent parameters for the drag-reducing flow with increasing Reynolds number showed that when the Reynolds number exceeded the drag-reducing region, the turbulent character was the same as that of water. The turbulent parameters of surfactant flow downstream the mesh plug showed that the high heat transfer region had the same turbulent intensity as that of water flow. As the critical Reynolds number was approached, it became easier to obtain such a turbulent region by mesh plug. In such cases, the mesh helped to create high wall shear stress and therefore to destroy the super-ordered structures of rod-like micelles for introducing turbulence. However, it was found that the turbulent intensities of the velocity gradually decreased to the same as those of drag-reducing flow downstream from the mesh because the mesh plug only produced a local high shear stress.

  19. Seismic Emissions Surveys | 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 Home Page on QA:QA J-E-1 SECTION JEnvironmental Jump to:EA EIS Report UrlNM-bRenewableSMUDSectional Model FlumeSeeo Jump

  20. Enormous sums of money are invested by industry and scientific funding agencies every year in seismic, well log-

    E-Print Network [OSTI]

    in seismic, well log- ging, electromagnetic, earthquake monitoring and micro- seismic surveys, and in laboratory-based experiments. For each survey or experiment a design process must first take place. An efficient design is usually a compromise--a suit- able trade-off between information that is expected

  1. Tectonic Deformation of a Lacustrine Mudstone at Soda Lake Geothermal Field, Western Nevada, USA, from 3D Seismic Interpretation

    E-Print Network [OSTI]

    enhanced extension and pull-apart basins that bring about structural controls for geothermal systems comprehensive seismic survey of a geothermal system in the world Seismic Survey The authors would like to thankTectonic Deformation of a Lacustrine Mudstone at Soda Lake Geothermal Field, Western Nevada, USA

  2. Two-dimensional

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPP UPDATE: April 15, 2014Twodimensional time resolved

  3. Fracture Properties From Seismic Scattering

    E-Print Network [OSTI]

    Burns, Daniel R.

    2007-01-01

    Fractures scatter seismic energy and this energy can be analyzed to provide information about fracture

  4. Method of migrating seismic records

    DOE Patents [OSTI]

    Ober, Curtis C. (Las Lunas, NM); Romero, Louis A. (Albuquerque, NM); Ghiglia, Dennis C. (Longmont, CO)

    2000-01-01

    The present invention provides a method of migrating seismic records that retains the information in the seismic records and allows migration with significant reductions in computing cost. The present invention comprises phase encoding seismic records and combining the encoded seismic records before migration. Phase encoding can minimize the effect of unwanted cross terms while still allowing significant reductions in the cost to migrate a number of seismic records.

  5. Idaho National Laboratory (INL) Seismic Initiative | Department...

    Office of Environmental Management (EM)

    Initiative Idaho National Laboratory (INL) Seismic Initiative Presentation from the May 2015 Seismic Lessons-Learned Panel Meeting. INL Seismic Initiative More Documents &...

  6. Aspects of earthquake triggering and seismicity clustering /

    E-Print Network [OSTI]

    Chen, Xiaowei

    2013-01-01

    relocated catalog. We process the seismic waveforms tolink between seismic events and calving processes in the twobetween seismic events and glacier sliding processes (e.g. ,

  7. Resonant seismic emission of subsurface objects

    E-Print Network [OSTI]

    Korneev, Valeri A.

    2010-01-01

    E . , and S. Keydar, 1998, Seismic monitoring of diffractionthe barrel. The Resonant Seismic Emission Source ReceiverFigure 1. Geometry o f the seismic experiment to locate a

  8. Seismic demands in precast concrete diaphragms

    E-Print Network [OSTI]

    Schoettler, Matthew John

    2010-01-01

    and Mander, J. B. (2003). “Seismic Performance of PrecastState-of-the-Art Report on Seismic Resistance of Prestresseddevelopment of a diaphragm seismic design methodology,” PCI

  9. Seismic Line Location Map Hot Pot Project, Humboldt County, Nevada 2010

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Michael Lane

    2010-01-01

    Seismic Line Location Map Hot Pot Project, Humboldt County, Nevada 2010. ArcGIS map package containing topographic base map, Township and Range layer, Oski BLM and private leases at time of survey, and locations, with selected shot points, of the five seismic lines.

  10. Marine seismic sources: QC of wavefield computation from near-field pressure

    E-Print Network [OSTI]

    Marine seismic sources: QC of wavefield computation from near-field pressure measurements1 A.M. Ziolkowski2 and R.G.K. Johnston2 Abstract A commercial marine seismic survey has been completed was obtained from the same calibration data set by minimizing the energy in the computed notional source

  11. Seismic Line Location Map Hot Pot Project, Humboldt County, Nevada 2010

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Michael Lane

    Seismic Line Location Map Hot Pot Project, Humboldt County, Nevada 2010. ArcGIS map package containing topographic base map, Township and Range layer, Oski BLM and private leases at time of survey, and locations, with selected shot points, of the five seismic lines.

  12. Equation of state of a weakly interacting two-dimensional Bose gas studied at zero temperature by means of quantum Monte Carlo methods

    SciTech Connect (OSTI)

    Astrakharchik, G. E.; Boronat, J.; Casulleras, J.; Kurbakov, I. L.; Lozovik, Yu. E.

    2009-05-15

    The equation of state of a weakly interacting two-dimensional Bose gas is studied at zero temperature by means of quantum Monte Carlo methods. Going down to as low densities as na{sup 2}{proportional_to}10{sup -100} permits us to obtain agreement on beyond mean-field level between predictions of perturbative methods and direct many-body numerical simulation, thus providing an answer to the fundamental question of the equation of state of a two-dimensional dilute Bose gas in the universal regime (i.e., entirely described by the gas parameter na{sup 2}). We also show that the measure of the frequency of a breathing collective oscillation in a trap at very low densities can be used to test the universal equation of state of a two-dimensional Bose gas.

  13. The inversion layer of electric fields and electron phase-space-hole structure during two-dimensional collisionless magnetic reconnection

    SciTech Connect (OSTI)

    Chen Lijen; Lefebvre, Bertrand; Torbert, Roy B.; Daughton, William S.

    2011-01-15

    Based on two-dimensional fully kinetic simulations that resolve the electron diffusion layer in undriven collisionless magnetic reconnection with zero guide field, this paper reports the existence and evolution of an inversion layer of bipolar electric fields, its corresponding phase-space structure (an electron-hole layer), and the implication to collisionless dissipation. The inversion electric field layer is embedded in the layer of bipolar Hall electric field and extends throughout the entire length of the electron diffusion layer. The electron phase-space hole structure spontaneously arises during the explosive growth phase when there exist significant inflows into the reconnection layer, and electrons perform meandering orbits across the layer while being cyclotron-turned toward the outflow directions. The cyclotron turning of meandering electrons by the magnetic field normal to the reconnection layer is shown to be a primary factor limiting the current density in the region where the reconnection electric field is balanced by the gradient (along the current sheet normal) of the off-diagonal electron pressure-tensor.

  14. Inferring orientation distributions in anisotropic powders of nano-layered crystallites from a single two-dimensional WAXS image

    E-Print Network [OSTI]

    Yves Meheust; Kenneth Dahl Knudsen; Jon Otto Fossum

    2006-02-01

    The wide-angle scattering of X-rays by anisotropic powders of nano-layered crystallites (nano-stacks) is addressed. Assuming that the orientation distribution probability function f of the nano-stacks only depends on the deviation of the crystallites' orientation from a fixed reference direction, we derive a relation providing f from the dependence of a given diffraction peak's amplitude on the azimuthal angle. The method is applied to two systems of Na-fluorohectorite (NaFH) clay particles, using synchrotron radiation and a WAXS setup with a two-dimensional detector. In the first system, which consists of dry-pressed NaFH samples, the orientation distribution probability function corresponds to a classical uniaxial nematic order. The second system is observed in bundles of polarized NaFH particles in silicon oil; in this case, the nanostacks have their directors on average in a plane normal to the reference direction, and f is a function of the angle between a nano-stack's director and that plane. In both cases, a suitable Maier-Saupe function is obtained for the distributions, and the reference direction is determined with respect to the laboratory frame. The method only requires one scattering image. Besides, consistency can be checked by determining the orientation distribution from several diffraction peaks independently.

  15. Electron Shock Surfing Acceleration in Multidimensions: Two-dimensional Particle-In-Cell Simulation of Collisionless Perpendicular Shock

    E-Print Network [OSTI]

    Takanobu Amano; Masahiro Hoshino

    2008-09-02

    Electron acceleration mechanism at high Mach number collisionless shocks propagating in a weakly magnetized medium is investigated by a self-consistent two-dimensional particle-in-cell simulation. Simulation results show that strong electrostatic waves are excited via the electron-ion electrostatic two-stream instability at the leading edge of the shock transition region as in the case of earlier one-dimensional simulations. We observe strong electron acceleration that is associated with the turbulent electrostatic waves in the shock transition region. The electron energy spectrum in the shock transition region exhibits a clear power-law distribution with spectral index of $2.0 {\\rm -} 2.5$. By analyzing the trajectories of accelerated electrons, we find that the acceleration mechanism is very similar to shock surfing acceleration of ions. In contrast to the ion shock surfing, however, the energetic electrons are reflected by electron-scale electrostatic fluctuations in the shock transition region, but not by the ion-scale cross-shock electrostatic potential. The reflected electrons are then accelerated by the convective electric field in front of the shock. We conclude that the multidimensional effects as well as the self-consistent shock structure are essential for the strong electron acceleration at high Mach number shocks.

  16. Two-dimensional water waves in the presence of a freely floating body: conditions for the absence of trapped modes

    E-Print Network [OSTI]

    Nikolay Kuznetsov

    2015-03-07

    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.

  17. Apparatus and method for heterodyne-generated two-dimensional detector array using a single element detector

    DOE Patents [OSTI]

    Strauss, C.E.

    1997-11-18

    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.

  18. Trigonometrical sums connected with the chiral Potts model, Verlinde dimension formula, two-dimensional resistor network, and number theory

    SciTech Connect (OSTI)

    Chair, Noureddine

    2014-02-15

    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.

  19. Two-dimensional hydrodynamic simulation of an accretion flow with radiative cooling in a close binary system

    E-Print Network [OSTI]

    Jun'ichi Sato; Keisuke Sawada; Naofumi Ohnishi

    2003-04-14

    Two-dimensional numerical simulations of an accretion flow in a close binary system are performed by solving the Euler equations with radiative transfer. In the present study, the specific heat ratio is assumed to be constant while radiative cooling effect is included as a non-adiabatic process. The cooling effect of the disc is considered by discharging energy in the vertical directions from the top and bottom surfaces of the disc. We use the flux-limited diffusion approximation to calculate the radiative heat flux values. Our calculations show that a disc structure appears and the spiral shocks are formed on the disc. These features are similar to that observed in the case of an adiabatic gas with a lower specific heat ratio, $\\gamma=1.01$. It is found that when radiative cooling effect is accounted for, the mass of the disc becomes larger than that assuming $\\gamma=5/3$, and smaller than that assuming $\\gamma=1.01$. It is concluded that employing an adiabatic gas with a lower specific heat ratio is almost a valid assumption for simulating accretion disc with radiative cooling effect.

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

    SciTech Connect (OSTI)

    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

    1994-07-01

    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.

  1. Apparatus and method for heterodyne-generated two-dimensional detector array using a single element detector

    DOE Patents [OSTI]

    Strauss, Charlie E. (Santa Fe, NM)

    1997-01-01

    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.

  2. Analysis of photonic band gaps in two-dimensional photonic crystals with rods covered by a thin interfacial layer

    SciTech Connect (OSTI)

    Trifonov, T.; Marsal, L.F.; Pallares, J.; Rodriguez, A.; Alcubilla, R.

    2004-11-15

    We investigate different aspects of the absolute photonic band gap (PBG) formation in two-dimensional photonic structures consisting of rods covered with a thin dielectric film. Specifically, triangular and honeycomb lattices in both complementary arrangements, i.e., air rods drilled in silicon matrix and silicon rods in air, are studied. We consider that the rods are formed of a dielectric core (silicon or air) surrounded by a cladding layer of silicon dioxide (SiO{sub 2}), silicon nitride (Si{sub 3}N{sub 4}), or germanium (Ge). Such photonic lattices present absolute photonic band gaps, and we study the evolution of these gaps as functions of the cladding material and thickness. Our results show that in the case of air rods in dielectric media the existence of dielectric cladding reduces the absolute gap width and may cause complete closure of the gap if thick layers are considered. For the case of dielectric rods in air, however, the existence of a cladding layer can be advantageous and larger absolute PBG's can be achieved.

  3. Using comprehensive two-dimensional gas chromatography to explore the geochemistry of the Santa Barbara oil seeps

    SciTech Connect (OSTI)

    Reddy, Christopher; Nelson, Robert

    2013-03-27

    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.

  4. Magnonic band structure, complete bandgap, and collective spin wave excitation in nanoscale two-dimensional magnonic crystals

    SciTech Connect (OSTI)

    Kumar, D.; Barman, A.; K?os, J. W.; Krawczyk, M.

    2014-01-28

    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.

  5. High-precision determination of low-energy effective parameters for a two-dimensional Heisenberg quantum antiferromagnet

    SciTech Connect (OSTI)

    Jiang, F.-J.; Wiese, U.-J.

    2011-04-15

    The two-dimensional (2D) spin-(1/2) Heisenberg antiferromagnet with exchange coupling J is investigated on a periodic square lattice of spacing a at very small temperatures using the loop-cluster algorithm. Monte Carlo data for the staggered and uniform susceptibilities are compared with analytic results obtained in the systematic low-energy effective field theory for the staggered magnetization order parameter. The low-energy parameters of the effective theory, i.e., the staggered magnetization density M{sub s}=0.307 43(1)/a{sup 2}, the spin stiffness {rho}{sub s}=0.180 81(11)J, and the spin wave velocity c=1.6586(3)Ja, are determined with very high precision. Our study may serve as a test case for the comparison of lattice quantum chromodynamics Monte Carlo data with analytic predictions of the chiral effective theory for pions and nucleons, which is vital for the quantitative understanding of the strong interaction at low energies.

  6. A naive matrix-model approach to two-dimensional quantum gravity coupled to matter of arbitrary central charge

    E-Print Network [OSTI]

    E. Brezin; S. Hikami

    1992-04-08

    In the usual matrix-model approach to random discretized two-dimensional manifolds, one introduces n Ising spins on each cell, i.e. a discrete version of 2D quantum gravity coupled to matter with a central charge n/2. The matrix-model consists then of an integral over $2^{n}$ matrices, which we are unable to solve for $n>1$. However for a fixed genus we can expand in the cosmological constant g for arbitrary values of n, and a simple minded analysis of the series yields for n=0,1 and 2 the expected results for the exponent $\\gamma_{string}$ with an amazing precision given the small number of terms that we considered. We then proceed to larger values of n. Simple tests of universality are successfully applied; for instance we obtain the same exponents for n=3 or for one Ising model coupled to a one dimensional target space. The calculations are easily extended to states Potts models, through an integration over $q^{n}$ matrices. We see no sign of the tachyonic instability of the theory, but we have only considered genus zero at this stage.

  7. Two-dimensional inflow-wind solution of black hole accretion with an evenly symmetric magnetic field

    E-Print Network [OSTI]

    Mosallanezhad, Amin; Yuan, Feng

    2015-01-01

    We solve the two-dimensional magnetohydrodynamic (MHD) equations of black hole accretion with the presence of magnetic field. The field includes a turbulent component, whose role is represented by the viscosity, and a large-scale ordered component. The latter is further assumed to be evenly symmetric with the equatorial plane. The equations are solved in the $r-\\theta$ plane of a spherical coordinate by assuming time-steady and radially self-similar. An inflow-wind solution is found. Around the equatorial plane, the gas is inflowing; while above and below the equatorial plane at a certain critical $\\theta$ angle, $\\theta\\sim 47^{\\circ}$, the inflow changes its direction of radial motion and becomes wind. The driving forces are analyzed and found to be the centrifugal force and the gradient of gas and magnetic pressure. The properties of wind are also calculated. The specific angular momentum of wind is found to be significantly larger than that of inflow, thus wind can transfer angular momentum outward. These...

  8. Seismic Safety Study

    SciTech Connect (OSTI)

    Tokarz, F J; Coats, D W

    2006-05-16

    During the past three decades, the Laboratory has been proactive in providing a seismically safe working environment for its employees and the general public. Completed seismic upgrades during this period have exceeded $30M with over 24 buildings structurally upgraded. Nevertheless, seismic questions still frequently arise regarding the safety of existing buildings. To address these issues, a comprehensive study was undertaken to develop an improved understanding of the seismic integrity of the Laboratory's entire building inventory at the Livermore Main Site and Site 300. The completed study of February 2005 extended the results from the 1998 seismic safety study per Presidential Executive Order 12941, which required each federal agency to develop an inventory of its buildings and to estimate the cost of mitigating unacceptable seismic risks. Degenkolb Engineers, who performed the first study, was recontracted to perform structural evaluations, rank order the buildings based on their level of seismic deficiencies, and to develop conceptual rehabilitation schemes for the most seriously deficient buildings. Their evaluation is based on screening procedures and guidelines as established by the Interagency Committee on Seismic Safety in Construction (ICSSC). Currently, there is an inventory of 635 buildings in the Laboratory's Facility Information Management System's (FIMS's) database, out of which 58 buildings were identified by Degenkolb Engineers that require seismic rehabilitation. The remaining 577 buildings were judged to be adequate from a seismic safety viewpoint. The basis for these evaluations followed the seismic safety performance objectives of DOE standard (DOE STD 1020) Performance Category 1 (PC1). The 58 buildings were ranked according to three risk-based priority classifications (A, B, and C) as shown in Figure 1-1 (all 58 buildings have structural deficiencies). Table 1-1 provides a brief description of their expected performance and damage state following a major earthquake, rating the seismic vulnerability (1-10) where the number 10 represents the highest and worst. Buildings in classifications A and B were judged to require the Laboratory's highest attention towards rehabilitation, classification C buildings could defer rehabilitation until a major remodel is undertaken. Strengthening schemes were developed by Degenkolb Engineers for the most seriously deficient A and B classifications (15 total), which the Laboratory's Plant Engineering Department used as its basis for rehabilitation construction cost estimates. A detailed evaluation of Building 2580, a strengthening scheme, and a construction cost estimate are pending. Specific details of the total estimated rehabilitation costs, a proposed 10-year seismic rehabilitation plan, exemption categories by building, DOE performance guidelines, cost comparisons for rehabilitation, and LLNL reports by Degenkolb Engineers are provided in Appendix A. Based on the results of Degenkolb Engineers evaluations, along with the prevailing practice for the disposition of seismically deficient buildings and risk-based evaluations, it is concluded that there is no need to evacuate occupants from these 58 buildings prior to their rehabilitation.

  9. Images of gravitational and magnetic phenomena derived from two-dimensional back-projection Doppler tomography of interacting binary stars

    SciTech Connect (OSTI)

    Richards, Mercedes T.; Cocking, Alexander S.; Fisher, John G.; Conover, Marshall J., E-mail: mrichards@astro.psu.edu, E-mail: asc5097@psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

    2014-11-10

    We have used two-dimensional back-projection Doppler tomography as a tool to examine the influence of gravitational and magnetic phenomena in interacting binaries that undergo mass transfer from a magnetically active star onto a non-magnetic main-sequence star. This multitiered study of over 1300 time-resolved spectra of 13 Algol binaries involved calculations of the predicted dynamical behavior of the gravitational flow and the dynamics at the impact site, analysis of the velocity images constructed from tomography, and the influence on the tomograms of orbital inclination, systemic velocity, orbital coverage, and shadowing. The H? tomograms revealed eight sources: chromospheric emission, a gas stream along the gravitational trajectory, a star-stream impact region, a bulge of absorption or emission around the mass-gaining star, a Keplerian accretion disk, an absorption zone associated with hotter gas, a disk-stream impact region, and a hot spot where the stream strikes the edge of a disk. We described several methods used to extract the physical properties of the emission sources directly from the velocity images, including S-wave analysis, the creation of simulated velocity tomograms from hydrodynamic simulations, and the use of synthetic spectra with tomography to sequentially extract the separate sources of emission from the velocity image. In summary, the tomography images have revealed results that cannot be explained solely by gravitational effects: chromospheric emission moving with the mass-losing star, a gas stream deflected from the gravitational trajectory, and alternating behavior between stream state and disk state. Our results demonstrate that magnetic effects cannot be ignored in these interacting binaries.

  10. Van der Waals Epitaxial Growth of Single-Crystal Two-Dimensional GaSe on Graphene

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

    Li, Xufan; Basile, Leonardo; Huang, Bing; Ma, Cheng; Lee, Jaekwang; Vlassiouk, Ivan V.; Puretzky, Alexander A.; Lin, Ming-Wei; Chi, Miaofang; Idrobo Tapia, Juan Carlos; et al

    2015-07-22

    Two-dimensional (2D) van der Waals (vdW) heterostructures are a family of artificially-structured materials that promise tunable optoelectronic properties for devices with enhanced functionalities. Compared to stamping, direct epitaxy of vdW heterostructures is ideal for clean interlayer interfaces and scalable device fabrication. Here, we explore the synthesis and preferred orientations of 2D GaSe atomic layers on graphene (Gr) by vdW epitaxy. Guided by the wrinkles on graphene, GaSe nuclei form that share a predominant lattice orientation. Due to vdW epitaxial growth many nuclei grow as perfectly aligned crystals and coalesce to form large (tens of microns), single-crystal flakes. Through theoretical investigationsmore »of interlayer energetics, and measurements of preferred orientations by atomic-resolution STEM and electron diffraction, a 10.9 interlayer rotation of the GaSe lattice with respect to the underlying graphene is found to be the most energetically preferred vdW heterostructure with the largest binding energy and the longest-range ordering. These GaSe/Gr vdW heterostructures exhibit an enhanced Raman E21g band of monolayer GaSe along with highly-quenched photoluminescence due to strong charge transfer. Despite the very large lattice mismatch of GaSe/Gr through vdW epitaxy, the predominant orientation control and convergent formation of large single-crystal flakes demonstrated here is promising for the scalable synthesis of large-area vdW heterostructures for the development of new optical and optoelectronic devices.« less

  11. Fast chemical reaction in a two-dimensional Navier-Stokes flow: Probability distribution in the initial regime

    E-Print Network [OSTI]

    Farid Ait-Chaalal; Michel S. Bourqui; Peter Bartello

    2011-10-17

    We study an instantaneous bimolecular chemical reaction in a two-dimensional chaotic, incompressible and closed Navier-Stokes flow. Areas of well mixed reactants are initially separated by infinite gradients. We focus on the initial regime, characterized by a well-defined one-dimensional contact line between the reactants. The amount of reactant consumed is given by the diffusive flux along this line, and hence relates directly to its length and to the gradients along it. We show both theoretically and numerically that the probability distribution of the modulus of the gradient of the reactants along this contact line multiplied by {\\kappa} does not depend on the diffusion {\\kappa} and can be inferred, after a few turnover times, from the joint distribution of the finite time Lyapunov exponent {\\lambda} and the frequency 1/{\\tau} . The equivalent time {\\tau} measures the stretching time scale of a Lagrangian parcel in the recent past, while {\\lambda} measures it on the whole chaotic orbit. At smaller times, we predict the shape of this gradient distribution taking into account the initial random orientation between the contact line and the stretching direction. We also show that the probability distribution of the reactants is proportional to {\\kappa} and to the product of the ensemble mean contact line length with the ensemble mean of the inverse of the gradient along it. Besides contributing to the understanding of fast chemistry in chaotic flows, the present study based on a Lagrangian stretching theory approach provides results that pave the way to the development of accurate sub- grid parametrizations in models with insufficient resolution for capturing the length scales relevant to chemical processes, for example in Climate-Chemsitry Models.

  12. Van der Waals epitaxial growth of two-dimensional single-crystalline GaSe domains on graphene

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

    Li, Xufan; Basile, Leonardo; Huang, Bing; Ma, Cheng; Lee, Jaekwang; Vlassiouk, Ivan V.; Puretzky, Alexander A.; Lin, Ming -Wei; Chi, Miaofang; Idrobo Tapia, Juan Carlos; et al

    2015-07-22

    Two-dimensional (2D) van der Waals (vdW) heterostructures are a family of artificially-structured materials that promise tunable optoelectronic properties for devices with enhanced functionalities. Compared to stamping, direct epitaxy of vdW heterostructures is ideal for clean interlayer interfaces and scalable device fabrication. Here, we explore the synthesis and preferred orientations of 2D GaSe atomic layers on graphene (Gr) by vdW epitaxy. Guided by the wrinkles on graphene, GaSe nuclei form that share a predominant lattice orientation. Due to vdW epitaxial growth many nuclei grow as perfectly aligned crystals and coalesce to form large (tens of microns), single-crystal flakes. Through theoretical investigationsmore »of interlayer energetics, and measurements of preferred orientations by atomic-resolution STEM and electron diffraction, a 10.9 interlayer rotation of the GaSe lattice with respect to the underlying graphene is found to be the most energetically preferred vdW heterostructure with the largest binding energy and the longest-range ordering. These GaSe/Gr vdW heterostructures exhibit an enhanced Raman E21g band of monolayer GaSe along with highly-quenched photoluminescence due to strong charge transfer. Despite the very large lattice mismatch of GaSe/Gr through vdW epitaxy, the predominant orientation control and convergent formation of large single-crystal flakes demonstrated here is promising for the scalable synthesis of large-area vdW heterostructures for the development of new optical and optoelectronic devices.« less

  13. Evaluation of a Vector Hypercube for Seismic Modelling Seismic modelling

    E-Print Network [OSTI]

    Renaut, Rosemary

    Evaluation of a Vector Hypercube for Seismic Modelling Abstract Seismic modelling is a computationally to produce realistic seismic traces intensive problem. A 2D syn- Rosemary Renautt and Johnny equation is the first step in the generation of a synthetic seismogram as an aid in the interpretation

  14. Anomalous dephasing scattering rate of two-dimensional electrons in double quantum well I. R. Pagnossin,1,* A. K. Meikap,2,

    E-Print Network [OSTI]

    Gusev, Guennady

    Anomalous dephasing scattering rate of two-dimensional electrons in double quantum well structures described from the point of view of contributions made by both the weak localization and electron-electron effect only. Using the weak localization method, we have determined the electron dephasing times

  15. 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]

    Weeks, Eric R.

    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. Protičre, Y. Couder

  16. A New Type of Two-Dimensional Metal Coordination Systems: Hydrothermal Synthesis and Properties of the First Oxalate-bpy Mixed-Ligand Framework

    E-Print Network [OSTI]

    Li, Jing

    A New Type of Two-Dimensional Metal Coordination Systems: Hydrothermal Synthesis and Properties, 290 °C; II, 340 °C; III, 350 °C; and IV, 290 °C). Introduction Investigation of novel inorganic-organic hybrid framework assemblies represents one of the most active areas of materials science and chemical

  17. Glass transition of two-dimensional binary soft-disk mixtures with large size ratios Rei Kurita* and Eric R. Weeks

    E-Print Network [OSTI]

    Weeks, Eric R.

    Glass transition of two-dimensional binary soft-disk mixtures with large size ratios Rei Kurita the glass transition. The "fragility" quantifies how sensitively the relaxation time scale depends.20.Ja, 64.60.My I. INTRODUCTION Many liquids can form glasses if they are cooled rapidly, and glassy

  18. Resonance and web structure in discrete soliton systems: the two-dimensional Toda lattice and its fully discrete and ultra-discrete versions

    E-Print Network [OSTI]

    Ken-ichi Maruno; Gino Biondini

    2005-04-09

    We present a class of solutions of the two-dimensional Toda lattice equation, its fully discrete analogue and its ultra-discrete limit. These solutions demonstrate the existence of soliton resonance and web-like structure in discrete integrable systems such as differential-difference equations, difference equations and cellular automata (ultra-discrete equations).

  19. The sti ness exponent of two-dimensional Ising spin glasses for non-periodic boundary conditions using aspect-ratio scaling

    E-Print Network [OSTI]

    Hartmann, Alexander K.

    The sti#11;ness exponent of two-dimensional Ising spin glasses for non-periodic boundary conditions a sti#11;ness exponent #18; = 0:287(4), which is independent of the boundary conditions in contrast-wall energy scales like M #18; in the thermodynamic limit, where #18; is the sti#11;ness exponent. If #18;

  20. Development of a hydraulic borehole seismic source

    SciTech Connect (OSTI)

    Cutler, R.P.

    1998-04-01

    This report describes a 5 year, $10 million Sandia/Industry project to develop an advanced borehole seismic source for use in oil and gas exploration and production. The development Team included Sandia, Chevron, Amoco, Conoco, Exxon, Raytheon, Pelton, and GRI. The seismic source that was developed is a vertically oriented, axial point force, swept frequency, clamped, reaction-mass vibrator design. It was based on an early Chevron prototype, but the new tool incorporates a number of improvements which make it far superior to the original prototype. The system consists of surface control electronics, a special heavy duty fiber optic wireline and draw works, a cablehead, hydraulic motor/pump module, electronics module, clamp, and axial vibrator module. The tool has a peak output of 7,000 lbs force and a useful frequency range of 5 to 800 Hz. It can operate in fluid filled wells with 5.5-inch or larger casing to depths of 20,000 ft and operating temperatures of 170 C. The tool includes fiber optic telemetry, force and phase control, provisions to add seismic receiver arrays below the source for single well imaging, and provisions for adding other vibrator modules to the tool in the future. The project yielded four important deliverables: a complete advanced borehole seismic source system with all associated field equipment; field demonstration surveys funded by industry showing the utility of the system; industrial sources for all of the hardware; and a new service company set up by their industrial partner to provide commercial surveys.