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1

Wide-band-gap InAlAs solar cell for an alternative multijunction approach Marina S. Leite,1,a  

E-Print Network [OSTI]

Wide-band-gap InAlAs solar cell for an alternative multijunction approach Marina S. Leite,1,a Robyn L. Woo,2 William D. Hong,2 Daniel C. Law,2 and Harry A. Atwater1 1 California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, USA 2 Boeing-Spectrolab Inc., 12500

Atwater, Harry

2

Novel wide band gap materials for highly efficient thin film tandem solar cells  

SciTech Connect (OSTI)

Tandem solar cells (TSCs), which use two or more materials to absorb sunlight, have achieved power conversion efficiencies of >25% versus 11-20% for commercialized single junction solar cell modules. The key to widespread commercialization of TSCs is to develop the wide-band, top solar cell that is both cheap to fabricate and has a high open-circuit voltage (i.e. >1V). Previous work in TSCs has generally focused on using expensive processing techniques with slow growth rates resulting in costs that are two orders of magnitude too expensive to be used in conventional solar cell modules. The objective of the PLANT PV proposal was to investigate the feasibility of using Ag(In,Ga)Se2 (AIGS) as the wide-bandgap absorber in the top cell of a thin film tandem solar cell (TSC). Despite being studied by very few in the solar community, AIGS solar cells have achieved one of the highest open-circuit voltages within the chalcogenide material family with a Voc of 949mV when grown with an expensive processing technique (i.e. Molecular Beam Epitaxy). PLANT PV�s goal in Phase I of the DOE SBIR was to 1) develop the chemistry to grow AIGS thin films via solution processing techniques to reduce costs and 2) fabricate new device architectures with high open-circuit voltage to produce full tandem solar cells in Phase II. PLANT PV attempted to translate solution processing chemistries that were successful in producing >12% efficient Cu(In,Ga)Se2 solar cells by replacing copper compounds with silver. The main thrust of the research was to determine if it was possible to make high quality AIGS thin films using solution processing and to fully characterize the materials properties. PLANT PV developed several different types of silver compounds in an attempt to fabricate high quality thin films from solution. We found that silver compounds that were similar to the copper based system did not result in high quality thin films. PLANT PV was able to deposit AIGS thin films using a mixture of solution and physical vapor deposition processing, but these films lacked the p-type doping levels that are required to make decent solar cells. Over the course of the project PLANT PV was able to fabricate efficient CIGS solar cells (8.7%) but could not achieve equivalent performance using AIGS. During the nine-month grant PLANT PV set up a variety of thin film characterization tools (e.g. drive-level capacitance profiling) at the Molecular Foundry, a Department of Energy User Facility, that are now available to both industrial and academic researchers via the grant process. PLANT PV was also able to develop the back end processing of thin film solar cells at Lawrence Berkeley National Labs to achieve 8.7% efficient CIGS solar cells. This processing development will be applied to other types of thin film PV cells at the Lawrence Berkeley National Labs. While PLANT PV was able to study AIGS film growth and optoelectronic properties we concluded that AIGS produced using these methods would have a limited efficiency and would not be commercially feasible. PLANT PV did not apply for the Phase II of this grant.

Brian E. Hardin, Stephen T. Connor, Craig H. Peters

2012-06-11T23:59:59.000Z

3

Final Report: Laser-Material Interactions Relevant to Analytic Spectroscopy of Wide Band Gap Materials  

SciTech Connect (OSTI)

We summarize our studies aimed at developing an understanding of the underlying physics and chemistry in terms of laser materials interactions relevant to laser-based sampling and chemical analysis of wide bandgap materials. This work focused on the determination of mechanisms for the emission of electrons, ions, atoms, and molecules from laser irradiation of surfaces. We determined the important role of defects on these emissions, the thermal, chemical, and physical interactions responsible for matrix effects and mass-dependent transport/detection. This work supported development of new techniques and technology for the determination of trace elements contained such as nuclear waste materials.

Dickinson, J. T. [Washington State University] [Washington State University

2014-04-05T23:59:59.000Z

4

Wide band gap semiconductor templates  

DOE Patents [OSTI]

The present invention relates to a thin film structure based on an epitaxial (111)-oriented rare earth-Group IVB oxide on the cubic (001) MgO terminated surface and the ion-beam-assisted deposition ("IBAD") techniques that are amendable to be over coated by semiconductors with hexagonal crystal structures. The IBAD magnesium oxide ("MgO") technology, in conjunction with certain template materials, is used to fabricate the desired thin film array. Similarly, IBAD MgO with appropriate template layers can be used for semiconductors with cubic type crystal structures.

Arendt, Paul N. (Los Alamos, NM); Stan, Liliana (Los Alamos, NM); Jia, Quanxi (Los Alamos, NM); DePaula, Raymond F. (Santa Fe, NM); Usov, Igor O. (Los Alamos, NM)

2010-12-14T23:59:59.000Z

5

Low band gap polymers Organic Photovoltaics  

E-Print Network [OSTI]

Low band gap polymers for Organic Photovoltaics Eva Bundgaard Ph.D. Dissertation Risř National Bundgaard Title: Low band gap polymers for Organic photovoltaics Department: The polymer department Report the area of organic photovoltaics are focusing on low band gap polymers, a type of polymer which absorbs

6

Narrow band gap amorphous silicon semiconductors  

DOE Patents [OSTI]

Disclosed is a narrow band gap amorphous silicon semiconductor comprising an alloy of amorphous silicon and a band gap narrowing element selected from the group consisting of Sn, Ge, and Pb, with an electron donor dopant selected from the group consisting of P, As, Sb, Bi and N. The process for producing the narrow band gap amorphous silicon semiconductor comprises the steps of forming an alloy comprising amorphous silicon and at least one of the aforesaid band gap narrowing elements in amount sufficient to narrow the band gap of the silicon semiconductor alloy below that of amorphous silicon, and also utilizing sufficient amounts of the aforesaid electron donor dopant to maintain the amorphous silicon alloy as an n-type semiconductor.

Madan, A.; Mahan, A.H.

1985-01-10T23:59:59.000Z

7

Single-junction solar cells with the optimum band gap for terrestrial concentrator applications  

DOE Patents [OSTI]

A single-junction solar cell having the ideal band gap for terrestrial concentrator applications. Computer modeling studies of single-junction solar cells have shown that the presence of absorption bands in the direct spectrum has the effect of "pinning" the optimum band gap for a wide range of operating conditions at a value of 1.14.+-.0.02 eV. Efficiencies exceeding 30% may be possible at high concentration ratios for devices with the ideal band gap.

Wanlass, Mark W. (Golden, CO)

1994-01-01T23:59:59.000Z

8

Fabrication of photonic band gap materials  

DOE Patents [OSTI]

A method for forming a periodic dielectric structure exhibiting photonic band gap effects includes forming a slurry of a nano-crystalline ceramic dielectric or semiconductor material and monodisperse polymer microspheres, depositing a film of the slurry on a substrate, drying the film, and calcining the film to remove the polymer microspheres therefrom. The film may be cold-pressed after drying and prior to calcining. The ceramic dielectric or semiconductor material may be titania, and the polymer microspheres may be polystyrene microspheres.

Constant, Kristen (Ames, IA); Subramania, Ganapathi S. (Ames, IA); Biswas, Rana (Ames, IA); Ho, Kai-Ming (Ames, IA)

2002-01-15T23:59:59.000Z

9

Substrate-Induced Band-Gap Opening in Epitaxial Graphene  

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

Substrate-Induced Band-Gap Opening in Epitaxial Graphene Substrate-Induced Band-Gap Opening in Epitaxial Graphene Print Wednesday, 26 March 2008 00:00 Prospective challengers to...

10

Substrate-induced band gap opening in epitaxial graphene  

E-Print Network [OSTI]

H.A. Electronic states of graphene nanoribbons studied withS.G. Louie. Energy gaps in graphene nanoribbons. Phys. Rev.band-gap engineering of graphene nanoribbons. Phys. Rev.

2008-01-01T23:59:59.000Z

11

Single-junction solar cells with the optimum band gap for terrestrial concentrator applications  

DOE Patents [OSTI]

A single-junction solar cell is described having the ideal band gap for terrestrial concentrator applications. Computer modeling studies of single-junction solar cells have shown that the presence of absorption bands in the direct spectrum has the effect of ''pinning'' the optimum band gap for a wide range of operating conditions at a value of 1.14[+-]0.02 eV. Efficiencies exceeding 30% may be possible at high concentration ratios for devices with the ideal band gap. 7 figures.

Wanlass, M.W.

1994-12-27T23:59:59.000Z

12

Method for Creating Photonic Band Gap Materials - Energy Innovation...  

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

a photonic band gap. These microstructures have the potential to change the way optoelectronic devices, such as photodiodes, LEDs, and integrated optical circuit elements, are...

13

acoustic band gaps: Topics by E-print Network  

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

type of phononic crystals manufactured Institute of Physics. DOI: 10.10631.2167794 The propagation of acoustic waves in periodic composite Deymier, Pierre 2 Acoustic band gap...

14

Substrate-Induced Band-Gap Opening in Epitaxial Graphene  

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

Substrate-Induced Band-Gap Opening in Epitaxial Graphene Print Prospective challengers to silicon, the long-reigning king of semiconductors for computer chips and other electronic...

15

Wide band stepped frequency ground penetrating radar  

DOE Patents [OSTI]

A wide band ground penetrating radar system (10) embodying a method wherein a series of radio frequency signals (60) is produced by a single radio frequency source (16) and provided to a transmit antenna (26) for transmission to a target (54) and reflection therefrom to a receive antenna (28). A phase modulator (18) modulates those portion of the radio frequency signals (62) to be transmitted and the reflected modulated signal (62) is combined in a mixer (34) with the original radio frequency signal (60) to produce a resultant signal (53) which is demodulated to produce a series of direct current voltage signals (66) the envelope of which forms a cosine wave shaped plot (68) which is processed by a Fast Fourier Transform unit 44 into frequency domain data (70) wherein the position of a preponderant frequency is indicative of distance to the target (54) and magnitude is indicative of the signature of the target (54).

Bashforth, Michael B. (Buellton, CA); Gardner, Duane (Santa Maria, CA); Patrick, Douglas (Santa Maria, CA); Lewallen, Tricia A. (Ventura, CA); Nammath, Sharyn R. (Santa Barbara, CA); Painter, Kelly D. (Goleta, CA); Vadnais, Kenneth G. (Alexandria, VA)

1996-01-01T23:59:59.000Z

16

Optical absorption and band gap reduction in (Fe1-xCrx)2O3 solid...  

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

Optical absorption and band gap reduction in (Fe1-xCrx)2O3 solid solutions: A first-principles study. Optical absorption and band gap reduction in (Fe1-xCrx)2O3 solid solutions: A...

17

Substrate-Induced Band-Gap Opening in Epitaxial Graphene  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystalline Gallium Oxide ThinIon CoolingSubstrateSubstrate-Induced Band-Gap

18

Substrate-Induced Band-Gap Opening in Epitaxial Graphene  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystalline Gallium Oxide ThinIonSubstrate-Induced Band-Gap Opening in

19

Voltage-matched, monolithic, multi-band-gap devices  

SciTech Connect (OSTI)

Monolithic, tandem, photonic cells include at least a first semiconductor layer and a second semiconductor layer, wherein each semiconductor layer includes an n-type region, a p-type region, and a given band-gap energy. Formed within each semiconductor layer is a sting of electrically connected photonic sub-cells. By carefully selecting the numbers of photonic sub-cells in the first and second layer photonic sub-cell string(s), and by carefully selecting the manner in which the sub-cells in a first and second layer photonic sub-cell string(s) are electrically connected, each of the first and second layer sub-cell strings may be made to achieve one or more substantially identical electrical characteristics.

Wanlass, Mark W.; Mascarenhas, Angelo

2006-08-22T23:59:59.000Z

20

Voltage-Matched, Monolithic, Multi-Band-Gap Devices  

DOE Patents [OSTI]

Monolithic, tandem, photonic cells include at least a first semiconductor layer and a second semiconductor layer, wherein each semiconductor layer includes an n-type region, a p-type region, and a given band-gap energy. Formed within each semiconductor layer is a string of electrically connected photonic sub-cells. By carefully selecting the numbers of photonic sub-cells in the first and second layer photonic sub-cell string(s), and by carefully selecting the manner in which the sub-cells in a first and second layer photonic sub-cell string(s) are electrically connected, each of the first and second layer sub-cell strings may be made to achieve one or more substantially identical electrical characteristics.

Wanlass, M. W.; Mascarenhas, A.

2006-08-22T23:59:59.000Z

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


21

Modeling of Photonic Band Gap Crystals and Applications  

SciTech Connect (OSTI)

In this work, the authors have undertaken a theoretical approach to the complex problem of modeling the flow of electromagnetic waves in photonic crystals. The focus is to address the feasibility of using the exciting phenomena of photonic gaps (PBG) in actual applications. The authors start by providing analytical derivations of the computational electromagnetic methods used in their work. They also present a detailed explanation of the physics underlying each approach, as well as a comparative study of the strengths and weaknesses of each method. The Plane Wave expansion, Transfer Matrix, and Finite Difference time Domain Methods are addressed. They also introduce a new theoretical approach, the Modal Expansion Method. They then shift the attention to actual applications. They begin with a discussion of 2D photonic crystal wave guides. The structure addressed consists of a 2D hexagonal structure of air cylinders in a layered dielectric background. Comparison with the performance of a conventional guide is made, as well as suggestions for enhancing it. The studies provide an upper theoretical limit on the performance of such guides, as they assumed no crystal imperfections and non-absorbing media. Next, they study 3D metallic PBG materials at near infrared and optical wavelengths. The main objective is to study the importance of absorption in the metal and the suitability of observing photonic band gaps in such structures. They study simple cubic structures where the metallic scatters are either cubes or interconnected metallic rods. Several metals are studied (aluminum, gold, copper, and silver). The effect of topology is addressed and isolated metallic cubes are found to be less lossy than the connected rod structures. The results reveal that the best performance is obtained by choosing metals with a large negative real part of the dielectric function, together with a relatively small imaginary part. Finally, they point out a new direction in photonic crystal research that involves the interplay of metallic-PBG rejection and photonic band edge absorption. They propose that an absolute metallic-PBG may be used to suppress the infrared part of the blackbody emission and, emit its energy only through a sharp absorption band. Potential applications of this new PBG mechanism include highly efficient incandescent lamps and enhanced thermophotovoltaic energy conversion. The suggested lamp would be able to recycle the energy that would otherwise go into the unwanted heat associated with usual lamps, into light emitted in the visible spectrum. It is estimated this would increase the efficiency over conventional lamps by about 40%.

Ihab Fathy El-Kady

2002-08-27T23:59:59.000Z

22

Recent emission channeling studies in wide band gap semiconductors  

E-Print Network [OSTI]

We present results of recent emission channeling experiments on the lattice location of implanted Fe and rare earths in wurtzite GaN and ZnO. In both cases the majority of implanted atoms are found on substitutional cation sites. The root mean square displacements from the ideal substitutional Ga and Zn sites are given and the stability of the Fe and rare earth lattice location against thermal annealing is discussed.

Wahl, Ulrich; Rita, E; Alves, E; Carvalho-Soares, Joăo; De Vries, Bart; Matias, V; Vantomme, A

2005-01-01T23:59:59.000Z

23

Wide-band heterodyne receiver development for effluent measurements  

SciTech Connect (OSTI)

Oak Ridge National Laboratory (ORNL) has been developing advanced infrared heterodyne receivers for plasma diagnostics in fusion reactors for over 20 years. Passive heterodyne radiometry in the LWIR region of the spectrum has historically been restricted by HgCdTe (MCT) detector technology to receiver bandwidths of only 2 GHz. Given typical atmospheric line widths of approximately 3 GHz, a CO{sub 2} (or isotope) laser local oscillator with an average line spacing of 50 GHz, and an MCT detector, only chemical species whose absorptions fall directly on top of laser lines can be measured. Thus, with traditional narrow-band heterodyne radiometry, much of the LWIR spectrum is missed and the less complex direct detection DIAL has been the preferred technique in remote sensing applications. Wide-band heterodyne receivers offer significant improvements in remote measurement capability. Progress at the Institute for Microstructural Sciences (IMS) at National Research Council of Canada and at ORNL in wide-band quantum-well infrared photodetectors (QIPs) and receivers is significantly enhancing the bandwidth capabilities of heterodyne radiometers. ORNL recently made measurements in the lab using QWIPs developed at IMS that demonstrate heterodyne quantum efficiencies of 5% with a heterodyne bandwidth of 7 GHz. The path forward indicates that > 10% heterodyne quantum efficiencies and 30-GHz bandwidths are achievable with current QWIP technology. With a chopped, 30-GHz passive heterodyne receiver, a much larger portion of the LWIR spectrum can now be covered. One potential advantage of wide-band heterodyne receivers for effluent measurements is to dramatically reduce the number of laser lines needed to characterize and distinguish multiple chemical species of interest. In the following paper, the authors discuss this and other implications of these new technologies to the characterization of effluents using both passive heterodyne radiometry and thermo-luminescence.

Hutchinson, D.P.; Richards, R.K.; Simpson, M.L.; Bennett, C.A. [Oak Ridge National Lab., TN (United States); Liu, H.C.; Buchanan, M. [National Research Council of Canada (Canada)

1998-05-01T23:59:59.000Z

24

Electronic structure of Pt based topological Heusler compounds with C1{sub b} structure and 'zero band gap'  

SciTech Connect (OSTI)

Besides of their well-known wide range of properties it was recently shown that many of the heavy Heusler semiconductors with 1:1:1 composition and C1{sub b} structure exhibit a zero band gap behavior and are topological insulators induced by their inverted band structure. In the present study, the electronic structure of the Heusler compounds PtYSb and PtLaBi was investigated by bulk sensitive hard x-ray photoelectron spectroscopy. The measured valence band spectra are clearly resolved and in well agreement to the first-principles calculations of the electronic structure of the compounds. The experimental results give clear evidence for the zero band gap state.

Ouardi, Siham; Shekhar, Chandra; Fecher, Gerhard H.; Kozina, Xeniya; Stryganyuk, Gregory; Felser, Claudia [Institut fuer Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Ueda, Shigenori; Kobayashi, Keisuke [NIMS Beamline Station at SPring-8, National Institute for Materials Science, Hyogo 679-5148 (Japan)

2011-05-23T23:59:59.000Z

25

Light trapping design for low band-gap polymer solar cells  

E-Print Network [OSTI]

Light trapping design for low band-gap polymer solar cells Stephen Foster1,* and Sajeev John1,2 1 demonstrate numerically a 2-D nanostructured design for light trapping in a low band-gap polymer solar cell, "Light harvesting improvement of organic solar cells with self- enhanced active layer designs," Opt

John, Sajeev

26

Wide band cryogenic ultra-high vacuum microwave absorber  

DOE Patents [OSTI]

An absorber wave guide assembly for absorbing higher order modes of microwave energy under cryogenic ultra-high vacuum conditions, that absorbs wide-band multi-mode energy. The absorber is of a special triangular shape, made from flat tiles of silicon carbide and aluminum nitride. The leading sharp end of the absorber is located in a corner of the wave guide and tapers to a larger cross-sectional area whose center is located approximately in the center of the wave guide. The absorber is relatively short, being of less height than the maximum width of the wave guide.

Campisi, Isidoro E. (Newport News, VA)

1992-01-01T23:59:59.000Z

27

Wide band cryogenic ultra-high vacuum microwave absorber  

DOE Patents [OSTI]

An absorber waveguide assembly for absorbing higher order modes of microwave energy under cryogenic ultra-high vacuum conditions, that absorbs wide-band multi-mode energy. The absorber is of a special triangular shape, made from flat tiles of silicon carbide and aluminum nitride. The leading sharp end of the absorber is located in a corner of the waveguide and tapers to a larger cross-sectional area whose center is located approximately in the center of the wave guide. The absorber is relatively short, being of less height than the maximum width of the waveguide. 11 figs.

Campisi, I.E.

1992-05-12T23:59:59.000Z

28

Ultra Wide Band RFID Neutron Tags for Nuclear Materials Monitoring  

SciTech Connect (OSTI)

Recent advancements in the ultra-wide band Radio Frequency Identification (RFID) technology and solid state pillar type neutron detectors have enabled us to move forward in combining both technologies for advanced neutron monitoring. The LLNL RFID tag is totally passive and will operate indefinitely without the need for batteries. The tag is compact, can be directly mounted on metal, and has high performance in dense and cluttered environments. The LLNL coin-sized pillar solid state neutron detector has achieved a thermal neutron detection efficiency of 20% and neutron/gamma discrimination of 1E5. These performance values are comparable to a fieldable {sup 3}He based detector. In this paper we will discuss features about the two technologies and some potential applications for the advanced safeguarding of nuclear materials.

Nekoogar, F; Dowla, F; Wang, T

2010-01-27T23:59:59.000Z

29

Wide-band coherent receiver development for enhanced surveillance  

SciTech Connect (OSTI)

Oak Ridge National Laboratory (ORNL) has been developing advanced coherent IR heterodyne receivers for plasma diagnostics in fusion reactors for over 20 years. Recent progress in wide band IR detectors and high speed electronics has significantly enhanced the measurement capabilities of coherent receivers. In addition, developments in new HgCdTe and quantum well IR photodetector (QWIP) focal plane arrays are providing the possibility of both active and passive coherent imaging. In this paper the authors discuss the implications of these new enabling technologies to the IR remote sensing community for enhanced surveillance. Coherent receivers, as opposed to direct or thermal detection, provide multiple dimensions of information about a scene or target in a single detector system. Combinations of range, velocity, temperature, and chemical species information are all available from a coherent heterodyne receiver. They present laboratory data showing measured noise equivalent power (NEP) of new QWIP detectors with heterodyne bandwidths greater than 7 GHz. For absorption measurements, a wide band coherent receiver provides the capability of looking between CO{sub 2} lines at off-resonance peaks and thus the measurement of lines normally inaccessible with conventional heterodyne or direct detection systems. Also described are differential absorption lidar (DIAL) and Doppler laboratory measurements using an 8 x 8 HgCdTe focal plane array demonstrating the snapshot capability of coherent receiver detector arrays for enhanced chemical plume and moving hardbody capture. Finally they discuss a variety of coherent receiver configurations that can suppress (or enhance) sensitivity of present active remote sensing systems to speckle, glint, and other measurement anomalies.

Simpson, M.L.; Richards, R.K.; Hutchinson, D.P.

1998-03-01T23:59:59.000Z

30

L-asparagine crystals with wide gap semiconductor features: Optical absorption measurements and density functional theory computations  

SciTech Connect (OSTI)

Results of optical absorption measurements are presented together with calculated structural, electronic, and optical properties for the anhydrous monoclinic L-asparagine crystal. Density functional theory (DFT) within the generalized gradient approximation (GGA) including dispersion effects (TS, Grimme) was employed to perform the calculations. The optical absorption measurements revealed that the anhydrous monoclinic L-asparagine crystal is a wide band gap material with 4.95 eV main gap energy. DFT-GGA+TS simulations, on the other hand, produced structural parameters in very good agreement with X-ray data. The lattice parameter differences ?a, ?b, ?c between theory and experiment were as small as 0.020, 0.051, and 0.022 Ĺ, respectively. The calculated band gap energy is smaller than the experimental data by about 15%, with a 4.23 eV indirect band gap corresponding to Z???? and Z???? transitions. Three other indirect band gaps of 4.30 eV, 4.32 eV, and 4.36 eV are assigned to ?3 ???, ?1 ???, and ?2 ??? transitions, respectively. ?-sol computations, on the other hand, predict a main band gap of 5.00 eV, just 50 meV above the experimental value. Electronic wavefunctions mainly originating from O 2p–carboxyl, C 2p–side chain, and C 2p–carboxyl orbitals contribute most significantly to the highest valence and lowest conduction energy bands, respectively. By varying the lattice parameters from their converged equilibrium values, we show that the unit cell is less stiff along the b direction than for the a and c directions. Effective mass calculations suggest that hole transport behavior is more anisotropic than electron transport, but the mass values allow for some charge mobility except along a direction perpendicular to the molecular layers of L-asparagine which form the crystal, so anhydrous monoclinic L-asparagine crystals could behave as wide gap semiconductors. Finally, the calculations point to a high degree of optical anisotropy for the absorption and complex dielectric function, with more structured curves for incident light polarized along the 100 and 101 directions.

Zanatta, G.; Gottfried, C. [Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, 90035-003 Porto Alegre-RS (Brazil)] [Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, 90035-003 Porto Alegre-RS (Brazil); Silva, A. M. [Universidade Estadual do Piauí, 64260-000 Piripiri-Pi (Brazil)] [Universidade Estadual do Piauí, 64260-000 Piripiri-Pi (Brazil); Caetano, E. W. S., E-mail: ewcaetano@gmail.com [Instituto de Educaçăo, Cięncia e Tecnologia do Ceará, 60040-531 Fortaleza-CE (Brazil)] [Instituto de Educaçăo, Cięncia e Tecnologia do Ceará, 60040-531 Fortaleza-CE (Brazil); Sales, F. A. M.; Freire, V. N. [Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, 60455-760 Fortaleza-CE (Brazil)] [Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, 60455-760 Fortaleza-CE (Brazil)

2014-03-28T23:59:59.000Z

31

Blueshift of optical band gap in ZnO thin films grown by metal-organic chemical-vapor deposition  

E-Print Network [OSTI]

. INTRODUCTION Zinc oxide ZnO is a wide direct band-gap 3.37 eV semiconductor with a broad range of applications. Dimethylzinc DMZn , N2 gas, and high-purity O2 were used as the zinc source, carrier gas, and oxidizing agent including light-emitting devices,1 varistors,2 solar cells,3 and gas sensors.4 Moreover, ZnO is a promising

32

X-Band Photonic Band-Gap Accelerator Structure Breakdown Experiment  

SciTech Connect (OSTI)

In order to understand the performance of photonic band-gap (PBG) structures under realistic high gradient, high power, high repetition rate operation, a PBG accelerator structure was designed and tested at X band (11.424 GHz). The structure consisted of a single test cell with matching cells before and after the structure. The design followed principles previously established in testing a series of conventional pillbox structures. The PBG structure was tested at an accelerating gradient of 65 MV/m yielding a breakdown rate of two breakdowns per hour at 60 Hz. An accelerating gradient above 110 MV/m was demonstrated at a higher breakdown rate. Significant pulsed heating occurred on the surface of the inner rods of the PBG structure, with a temperature rise of 85 K estimated when operating in 100 ns pulses at a gradient of 100 MV/m and a surface magnetic field of 890 kA/m. A temperature rise of up to 250 K was estimated for some shots. The iris surfaces, the location of peak electric field, surprisingly had no damage, but the inner rods, the location of the peak magnetic fields and a large temperature rise, had significant damage. Breakdown in accelerator structures is generally understood in terms of electric field effects. These PBG structure results highlight the unexpected role of magnetic fields in breakdown. The hypothesis is presented that the moderate level electric field on the inner rods, about 14 MV/m, is enhanced at small tips and projections caused by pulsed heating, leading to breakdown. Future PBG structures should be built to minimize pulsed surface heating and temperature rise.

Marsh, Roark A.; /MIT /MIT /NIFS, Gifu /JAERI, Kyoto /LLNL, Livermore; Shapiro, Michael A.; Temkin, Richard J.; /MIT; Dolgashev, Valery A.; Laurent, Lisa L.; Lewandowski, James R.; Yeremian, A.Dian; Tantawi, Sami G.; /SLAC

2012-06-11T23:59:59.000Z

33

OPTIMIZATION OF GRADED BAND GAP CdHgTe SOLAR CELLS A. BOUAZZI (*), Y. MARFAING and J. MIMILA-ARROYO  

E-Print Network [OSTI]

145 OPTIMIZATION OF GRADED BAND GAP CdHgTe SOLAR CELLS A. BOUAZZI (*), Y. MARFAING and J. MIMILA and an n-type CdHgTe alloy of uniform band gap as the base region. The optimization of solar energy conversion is conducted with respect to two constitutive para- meters : the gradient of the band gap

Boyer, Edmond

34

Tunable frequency band-gap and pulse propagation in a strongly nonlinear diatomic chain  

E-Print Network [OSTI]

One-dimensional nonlinear phononic crystals have been assembled from periodic diatomic chains of stainless steel cylinders alternated with Polytetrafluoroethylene (PTFE) spheres. We report the presence of acoustic band gaps in the dispersion relation of the linearized systems and study the transformation of single and multiple pulses in linear, nonlinear and strongly nonlinear regimes with numerical calculations and experiments. The limiting frequencies of the band gap are within the audible frequency range (20-20,000 Hz) and can be tuned by varying the particle's material properties, mass and initial compression. Pulses rapidly transform within very short distances from the impacted end due to the influence of the band gap in the linear and in nonlinear elastic chains. The effects of an in situ band gap created by a mean dynamic compression are observed in the strongly nonlinear wave regime.

E. B. Herbold; J. Kim; V. F. Nesterenko; S. Wang; C. Daraio

2008-06-26T23:59:59.000Z

35

Calculation of wakefields in a 17 GHz beam-driven photonic band-gap accelerator structure  

E-Print Network [OSTI]

We present the theoretical analysis and computer simulation of the wakefields in a 17 GHz photonic band-gap (PBG) structure for accelerator applications. Using the commercial code CST Particle Studio, the fundamental ...

Hu, Min

36

Thermophotovoltaic conversion using selective infrared line emitters and large band gap photovoltaic devices  

DOE Patents [OSTI]

Efficient thermophotovoltaic conversion can be performed using photovoltaic devices with a band gap in the 0.75-1.4 electron volt range, and selective infrared emitters chosen from among the rare earth oxides which are thermally stimulated to emit infrared radiation whose energy very largely corresponds to the aforementioned band gap. It is possible to use thermovoltaic devices operating at relatively high temperatures, up to about 300.degree. C., without seriously impairing the efficiency of energy conversion.

Brandhorst, Jr., Henry W. (Auburn, AL); Chen, Zheng (Auburn, AL)

2000-01-01T23:59:59.000Z

37

One-dimensional electromagnetic band gap structures formed by discharge plasmas in a waveguide  

SciTech Connect (OSTI)

We demonstrate the ability to develop one-dimensional electromagnetic band gap structure in X-band waveguide solely by using the positive columns of glow discharges in neon at the middle pressure. Plasma inhomogeneities are distributed uniformly along a typical X-band waveguide with cross section of 23?×?10?mm{sup 2}. It is shown that electron densities larger than 10{sup 14?}cm{sup ?3} are needed in order to create an effective one-dimensional electromagnetic band gap structure. Some applications for using the one-dimensional electromagnetic band gap structure in waveguide as a control of microwave (broadband filter and device for variation of pulse duration) are demonstrated.

Arkhipenko, V. I.; Simonchik, L. V., E-mail: l.simonchik@dragon.bas-net.by; Usachonak, M. S. [B.I. Stepanov Institute of Physics of the NAS of Belarus, Ave. Nezavisimostsi 68, 220072 Minsk (Belarus); Callegari, Th.; Sokoloff, J. [Université de Toulouse, UPS, INPT, LAPLACE, Laboratoire Plasma et Conversion d'Energie, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France)

2014-09-28T23:59:59.000Z

38

Energy Band-Gap Engineering of Graphene Nanoribbons Melinda Y. Han,1  

E-Print Network [OSTI]

, New York, New York 10027, USA 2 Department of Physics, Columbia University, New York, New York 10027Energy Band-Gap Engineering of Graphene Nanoribbons Melinda Y. Han,1 Barbaros O¨ zyilmaz,2 Yuanbo an energy gap near the charge neutrality point. Individual graphene layers are contacted with metal

Kim, Philip

39

Band gap and electronic structure of MgSiN{sub 2}  

SciTech Connect (OSTI)

Density functional theory calculations and electron energy loss spectroscopy indicate that the electronic structure of ordered orthorhombic MgSiN{sub 2} is similar to that of wurtzite AlN. A band gap of 5.7?eV was calculated for both MgSiN{sub 2} (indirect) and AlN (direct) using the Heyd-Scuseria-Ernzerhof approximation. Correction with respect to the experimental room-temperature band gap of AlN indicates that the true band gap of MgSiN{sub 2} is 6.2?eV. MgSiN{sub 2} has an additional direct gap of 6.3?eV at the ? point.

Quirk, J. B., E-mail: james.quirk09@imperial.ac.uk; Rĺsander, M.; McGilvery, C. M.; Moram, M. A. [Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Palgrave, R. [Department of Chemistry, University College London, Gordon Street WC1H 0AJ (United Kingdom)

2014-09-15T23:59:59.000Z

40

Band gap engineering for graphene by using Na{sup +} ions  

SciTech Connect (OSTI)

Despite the noble electronic properties of graphene, its industrial application has been hindered mainly by the absence of a stable means of producing a band gap at the Dirac point (DP). We report a new route to open a band gap (E{sub g}) at DP in a controlled way by depositing positively charged Na{sup +} ions on single layer graphene formed on 6H-SiC(0001) surface. The doping of low energy Na{sup +} ions is found to deplete the ?* band of graphene above the DP, and simultaneously shift the DP downward away from Fermi energy indicating the opening of E{sub g}. The band gap increases with increasing Na{sup +} coverage with a maximum E{sub g}?0.70?eV. Our core-level data, C 1s, Na 2p, and Si 2p, consistently suggest that Na{sup +} ions do not intercalate through graphene, but produce a significant charge asymmetry among the carbon atoms of graphene to cause the opening of a band gap. We thus provide a reliable way of producing and tuning the band gap of graphene by using Na{sup +} ions, which may play a vital role in utilizing graphene in future nano-electronic devices.

Sung, S. J.; Lee, P. R.; Kim, J. G.; Ryu, M. T.; Park, H. M.; Chung, J. W., E-mail: jwc@postech.ac.kr [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

2014-08-25T23:59:59.000Z

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


41

Band gap structure modification of amorphous anodic Al oxide film by Ti-alloying  

SciTech Connect (OSTI)

The band structure of pure and Ti-alloyed anodic aluminum oxide has been examined as a function of Ti concentration varying from 2 to 20 at.?%. The band gap energy of Ti-alloyed anodic Al oxide decreases with increasing Ti concentration. X-ray absorption spectroscopy reveals that Ti atoms are not located in a TiO{sub 2} unit in the oxide layer, but rather in a mixed Ti-Al oxide layer. The optical band gap energy of the anodic oxide layers was determined by vacuum ultraviolet spectroscopy in the energy range from 4.1 to 9.2?eV (300–135?nm). The results indicate that amorphous anodic Al{sub 2}O{sub 3} has a direct band gap of 7.3?eV, which is about ?1.4?eV lower than its crystalline counterpart (single-crystal Al{sub 2}O{sub 3}). Upon Ti-alloying, extra bands appear within the band gap of amorphous Al{sub 2}O{sub 3}, mainly caused by Ti 3d orbitals localized at the Ti site.

Canulescu, S., E-mail: stec@fotonik.dtu.dk; Schou, J. [Department of Photonics Engineering, Technical University of Denmark, 4000 Roskilde (Denmark); Rechendorff, K.; Pleth Nielsen, L. [Danish Technological Institute, Kongsvang Alle 29, 8000 Aarhus (Denmark); Borca, C. N. [Paul Scherrer Institute, 5232 Villigen (Switzerland); Jones, N. C.; Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, 8000 Aarhus (Denmark); Bordo, K.; Ambat, R. [Department of Mechanical Engineering, Technical University of Denmark, 2800 Kongens Lyngby (Denmark)

2014-03-24T23:59:59.000Z

42

Method of manufacturing flexible metallic photonic band gap structures, and structures resulting therefrom  

DOE Patents [OSTI]

A method of manufacturing a flexible metallic photonic band gap structure operable in the infrared region, comprises the steps of spinning on a first layer of dielectric on a GaAs substrate, imidizing this first layer of dielectric, forming a first metal pattern on this first layer of dielectric, spinning on and imidizing a second layer of dielectric, and then removing the GaAs substrate. This method results in a flexible metallic photonic band gap structure operable with various filter characteristics in the infrared region. This method may be used to construct multi-layer flexible metallic photonic band gap structures. Metal grid defects and dielectric separation layer thicknesses are adjusted to control filter parameters.

Gupta, Sandhya (Bloomington, MN); Tuttle, Gary L. (Ames, IA); Sigalas, Mihail (Ames, IA); McCalmont, Jonathan S. (Ames, IA); Ho, Kai-Ming (Ames, IA)

2001-08-14T23:59:59.000Z

43

Direct measurements of band gap grading in polycrystalline CIGS solar cells  

E-Print Network [OSTI]

We present direct measurements of depth-resolved band gap variations of CuIn(1-x)Ga(x)Se2 thin-film solar cell absorbers. A new measurement technique combining parallel measurements of local thin-film interference and spectral photoluminescence was developed for this purpose. We find sample-dependent correlation parameters between measured band gap depth and composition profiles, and emphasize the importance of direct measurements. These results bring a quantitative insight into the electronic properties of the solar cells and open a new way to analyze parameters that determine the efficiency of solar cells.

M. P. Heinrich; Z-H. Zhang; Y. Zhang; O. Kiowski; M. Powalla; U. Lemmer; A. Slobodskyy

2010-09-20T23:59:59.000Z

44

Direct measurements of band gap grading in polycrystalline CIGS solar cells  

E-Print Network [OSTI]

We present direct measurements of depth-resolved band gap variations of CuIn(1-x)Ga(x)Se2 thin-film solar cell absorbers. A new measurement technique combining parallel measurements of local thin-film interference and spectral photoluminescence was developed for this purpose. We find sample-dependent correlation parameters between measured band gap depth and composition profiles, and emphasize the importance of direct measurements. These results bring a quantitative insight into the electronic properties of the solar cells and open a new way to analyze parameters that determine the efficiency of solar cells.

Heinrich, M P; Zhang, Y; Kiowski, O; Powalla, M; Lemmer, U; Slobodskyy, A

2010-01-01T23:59:59.000Z

45

Defect assistant band alignment transition from staggered to broken gap in mixed As/Sb tunnel field effect transistor heterostructure  

E-Print Network [OSTI]

.3As heterointerface. As a result, the band alignment was converted from staggered gap to broken gap-to-source voltage, VGS. As the SS of a MOSFET is governed by the transport mechanism of thermionic-emission over

Yener, Aylin

46

The Electrical and Band-Gap Properties of Amorphous Zinc-Indium-Tin Oxide Thin Films  

E-Print Network [OSTI]

MRSEC The Electrical and Band-Gap Properties of Amorphous Zinc-Indium-Tin Oxide Thin Films D Science & Engineering Center For zinc-indium-tin oxide (ZITO) films, grown by pulsed-laser deposition was replaced by substitution with zinc and tin in equal molar proportions (co-substitution). All ZITO films

Shahriar, Selim

47

Current transport, gate dielectrics and band gap engineering in graphene devices  

E-Print Network [OSTI]

Current transport, gate dielectrics and band gap engineering in graphene devices Wenjuan Zhu In this work, we studied current transport in mono-, bi- and tri-layer graphene. We find that both of the electrical field of the substrate surface polar phonons in bi-layer/tri-layer graphenes. We also find

Perebeinos, Vasili

48

Metallic photonic-band-gap filament architectures for optimized incandescent lighting Sajeev John and Rongzhou Wang  

E-Print Network [OSTI]

Metallic photonic-band-gap filament architectures for optimized incandescent lighting Sajeev John occur 3,4 . Tra- ditionally incandescent lighting filaments, despite being driven from equilibrium the blackbody spectrum. This suggests the pos- sibility of higher efficiency incandescent lighting, through

John, Sajeev

49

Size effect on the electronic and optical band gap of CdSe QD  

SciTech Connect (OSTI)

Present paper deals with a critical and comprehensive analysis of the dependence of photo emission (PE) electronic band gap and optical absorption (OA) excitonic band gap on the size of CdSe QD, via connecting it with excitonic absorbance wavelength. Excitonic absorbance wavelength is determined through an empirical fit of established experimental evidences. Effective excitonic charge and Bohr radius is determined as a function of size. Increase in size of the CdSe QD results in greater Bohr radius and smaller effective excitonic charge. Excitonic binding energy as a degree of size of QD is also calculated which further relates with the difference in PE electronic and OA optical band gaps. It is also shown that with increase in size of CdSe QD, the excitonic binding energy decreases which consequently increases differences in two band gaps. Our results are very well comparable with the established results. Explanation for the origin of the unusual optical properties of CdSe QD has been also discussed.

Sisodia, Namita, E-mail: namitasisodiya@gmail.com [Department of Physics, Holkar Science College, Indore-45200 (India)

2014-04-24T23:59:59.000Z

50

Exploiting pattern transformation to tune phononic band gaps in a two-dimensional granular crystal  

E-Print Network [OSTI]

) cylinders is investigated numerically. This system was previously shown to undergo a pattern transformation with uniaxial compression by Go¨ncu¨ et al. [Soft Matter 7, 2321 (2011)]. The dispersion relations, or elastic waves in certain frequency ranges known as band gaps is an important feature of these materials

51

Photonic band gap of a graphene-embedded quarter-wave stack  

SciTech Connect (OSTI)

Here, we present a mechanism for tailoring the photonic band structure of a quarter-wave stack without changing its physical periods by embedding conductive sheets. Graphene is utilized and studied as a realistic, two-dimensional conductive sheet. In a graphene-embedded quarter-wave stack, the synergic actions of Bragg scattering and graphene conductance contributions open photonic gaps at the center of the reduced Brillouin zone that are nonexistent in conventional quarter-wave stacks. Such photonic gaps show giant, loss-independent density of optical states at the fixed lower-gap edges, of even-multiple characteristic frequency of the quarter-wave stack. The conductive sheet-induced photonic gaps provide a platform for the enhancement of light-matter interactions.

Fan, Yuancheng [Ames Laboratory; Wei, Zeyong [Tongji University; Li, Hongqiang [Tongji University; Chen, Hong [Tongji University; Soukoulis, Costas M [Ames Laboratory

2013-12-10T23:59:59.000Z

52

Distributed Compressive Wide-Band Spectrum Ying Wang , Ashish Pandharipande , Yvan Lamelas Polo and Geert Leus  

E-Print Network [OSTI]

Distributed Compressive Wide-Band Spectrum Sensing Ying Wang , Ashish Pandharipande , Yvan Lamelas, The Netherlands Email: {ying.z.wang, ashish.p}@philips.com Faculty of EEMCS, Delft University of Technology

Leus, Geert

53

Fabrication of Ceramic Layer-by-Layer Infrared Wavelength Photonic Band Gap Crystals  

SciTech Connect (OSTI)

Photonic band gap (PBG) crystals, also known as photonic crystals, are periodic dielectric structures which form a photonic band gap that prohibit the propagation of electromagnetic (EM) waves of certain frequencies at any incident angles. Photonic crystals have several potential applications including zero-threshold semiconductor lasers, the inhibition of spontaneous emission, dielectric mirrors, and wavelength filters. If defect states are introduced in the crystals, light can be guided from one location to another or even a sharp bending of light in micron scale can be achieved. This generates the potential for optical waveguide and optical circuits, which will contribute to the improvement in the fiber-optic communications and the development of high-speed computers.

Henry Hao-Chuan Kang

2004-12-19T23:59:59.000Z

54

Band gap tuning in transition metal oxides by site-specific substitution  

DOE Patents [OSTI]

A transition metal oxide insulator composition having a tuned band gap includes a transition metal oxide having a perovskite or a perovskite-like crystalline structure. The transition metal oxide includes at least one first element selected form the group of Bi, Ca, Ba, Sr, Li, Na, Mg, K, Pb, and Pr; and at least one second element selected from the group of Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, Re, Os, Ir, and Pt. At least one correlated insulator is integrated into the crystalline structure, including REMO.sub.3, wherein RE is at least one Rare Earth element, and wherein M is at least one element selected from the group of Co, V, Cr, Ni, Mn, and Fe. The composition is characterized by a band gap of less of 4.5 eV.

Lee, Ho Nyung; Chisholm, Jr., Matthew F; Jellison, Jr., Gerald Earle; Singh, David J; Choi, Woo Seok

2013-12-24T23:59:59.000Z

55

Pre-Stressed Viscoelastic Composites: Effective Incremental Moduli and Band-Gap Tuning  

SciTech Connect (OSTI)

We study viscoelastic wave propagation along pre-stressed nonlinear elastic composite bars. In the pre-stressed state we derive explicit forms for the effective incremental storage and loss moduli with dependence on the pre-stress. We also derive a dispersion relation for the effective wavenumber in the case of arbitrary frequency, hence permitting a study of viscoelastic band-gap tuning via pre-stress.

Parnell, William J. [School of Mathematics, Alan Turing Building, University of Manchester, Manchester, M13 9PL (United Kingdom)

2010-09-30T23:59:59.000Z

56

Microwave band gap and cavity mode in spoof-insulator-spoof waveguide with multiscale structured surface  

E-Print Network [OSTI]

We propose a multiscale spoof-insulator-spoof (SIS) waveguide by introducing periodic geometry modulation in the wavelength scale to a SIS waveguide made of perfect electric conductor. The MSIS consists of multiple SIS subcells. The dispersion relationship of the fundamental guided mode of the spoof surface plasmon polaritons (SSPPs) is studied analytically within the small gap approximation. It is shown that the multiscale SIS possesses microwave band gap (MBG) due to the Bragg scattering. The "gap maps" in the design parameter space are provided. We demonstrate that the geometry of the subcells can efficiently adjust the effective refraction index of the elementary SIS and therefore further control the width and the position of the MBG. The results are in good agreement with numerical calculations by the finite element method (FEM). For finite-sized MSIS of given geometry in the millimeter scale, FEM calculations show that the first-order symmetric SSPP mode has zero transmission in the MBG within frequency...

Zhang, Qiang; Han, Dezhuan; Qin, Fei Fei; Zhang, Xiao Ming; Yao, Yong

2015-01-01T23:59:59.000Z

57

Photonic-band-gap properties for two-component slow light  

SciTech Connect (OSTI)

We consider two-component ''spinor'' slow light in an ensemble of atoms coherently driven by two pairs of counterpropagating control laser fields in a double tripod-type linkage scheme. We derive an equation of motion for the spinor slow light (SSL) representing an effective Dirac equation for a massive particle with the mass determined by the two-photon detuning. By changing the detuning the atomic medium acts as a photonic crystal with a controllable band gap. If the frequency of the incident probe light lies within the band gap, the light experiences reflection from the sample and can tunnel through it. For frequencies outside the band gap, the transmission and reflection probabilities oscillate with the increasing length of the sample. In both cases the reflection takes place into the complementary mode of the probe field. We investigate the influence of the finite excited state lifetime on the transmission and reflection coefficients of the probe light. We discuss possible experimental implementations of the SSL using alkali-metal atoms such as rubidium or sodium.

Ruseckas, J.; Kudriasov, V.; Juzeliunas, G.; Unanyan, R. G.; Otterbach, J.; Fleischhauer, M. [Institute of Theoretical Physics and Astronomy, Vilnius University, A. Gostauto 12, Vilnius 01108 (Lithuania); Fachbereich Physik and Research Center OPTIMAS, Technische Universitaet Kaiserslautern, Kaiserslautern D-67663 (Germany)

2011-06-15T23:59:59.000Z

58

Effect of silver incorporation in phase formation and band gap tuning of tungsten oxide thin films  

SciTech Connect (OSTI)

Silver incorporated tungsten oxide thin films are prepared by RF magnetron sputtering technique. The effect of silver incorporation in micro structure evolution, phase enhancement, band gap tuning and other optical properties are investigated using techniques such as x-ray diffraction, micro-Raman spectroscopy, atomic force microscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy, and UV-Visible spectroscopy. Effect of silver addition in phase formation and band gap tuning of tungsten oxide thin films are investigated. It is found that the texturing and phase formation improves with enhancement in silver content. It is also found that as the silver incorporation enhances the thickness of the films increases at the same time the strain in the film decreases. Even without annealing the desired phase can be achieved by doping with silver. A broad band centered at the wavelength 437 nm is observed in the absorption spectra of tungsten oxide films of higher silver incorporation and this can be attributed to surface plasmon resonance of silver atoms present in the tungsten oxide matrix. The transmittance of the films is decreased with increase in silver content which can be due to increase in film thickness, enhancement of scattering, and absorption of light caused by the increase of grain size, surface roughness and porosity of films and enhanced absorption due to surface plasmon resonance of silver. It is found that silver can act as the seed for the growth of tungsten oxide grains and found that the grain size increases with silver content which in turn decreases the band gap of tungsten oxide from 3.14 eV to 2.70 eV.

Jolly Bose, R.; Kumar, R. Vinod; Sudheer, S. K.; Mahadevan Pillai, V. P. [Department of Optoelectronics, University of Kerala, Kariyavattom, Thiruvananthapuram, Kerala 695581 (India); Reddy, V. R.; Ganesan, V. [UGC - DAE Consortium for Scientific Research, Khandwa Road, Indore 452017, Madhyapradesh (India)

2012-12-01T23:59:59.000Z

59

Spectra and gap amplification for systems with two widely different incommensurate periodicities  

SciTech Connect (OSTI)

We derive analytically the spectrum for the Schroedinger equation for quasiperiodic systems with two length scales: one large ''macroscopic'' scale (e.g., a-italic cos(2..pi..x-italic/lambda)) and one small ''microscopic'' scale (e.g., v-italic cos(2..pi..x-italic)). The phase diagram includes regimes with exponentially narrow gaps due to the slowly varying potential, regimes where the rapidly varying potential amplifies these narrow gaps, and regimes with exponentially narrow ''Landau bands.'' The full ''devil's-staircase'' spectrum with gaps at wave vectors q-italic = m-italic..pi..+n-italic..pi../lambda develops in a hierarchical manner as a-italic increases. The results apply to systems with superlattices, to celestial orbits with two periodic perturbations, to systems with slowly varying lattice distortions, and, in particular, to quasi-one-dimensional magnets such as bis(tetramethyltetraselenafulvalene) perchlorate ((TMTSF)/sub 2/ClO/sub 4/) in magnetic fields, where our findings may provide insight into the experimentally observed cascade of phase transitions.

Azbel, M.Y.; Bak, P.; Chaikin, P.M.

1986-08-01T23:59:59.000Z

60

Design and 3D simulation of a two-cavity wide-gap relativistic klystron amplifier with high power injection  

SciTech Connect (OSTI)

By using an electromagnetic particle-in-cell (PIC) code, an S-band two-cavity wide-gap klystron amplifier (WKA) loaded with washers/rods structure is designed and investigated for high power injection application. Influences of the washers/rods structure on the high frequency characteristics and the basic operation of the amplifier are presented. Generally, the rod structure has great impacts on the space-charge potential depression and the resonant frequency of the cavities. Nevertheless, if only the resonant frequency is tuned to the desired operation frequency, effects of the rod size on the basic operation of the amplifier are expected to be very weak. The 3-dimension (3-D) PIC simulation results show an output power of 0.98 GW corresponding to an efficiency of 33% for the WKA, with a 594 keV, 5 kA electron beam guided by an external magnetic field of 1.5 Tesla. Moreover, if a conductive plane is placed near the output gap, such as the electron collector, the beam potential energy can be further released, and the RF power can be increased to about 1.07 GW with the conversion efficiency of about 36%.

Bai Xianchen; Yang Jianhua; Zhang Jiande [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2012-08-15T23:59:59.000Z

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


61

Waveguides in three-dimensional metallic photonic band-gap materials  

SciTech Connect (OSTI)

We theoretically investigate waveguide structures in three-dimensional metallic photonic band-gap (MPBG) materials. The MPBG materials used in this study consist of a three-dimensional mesh of metallic wires embedded in a dielectric. An {ital L}-shaped waveguide is created by removing part of the metallic wires. Using finite difference time domain simulations, we found that an 85{percent} transmission efficiency can be achieved through the 90{degree} bend with just three unit cell thickness MPBG structures. thinsp {copyright} {ital 1999} {ital The American Physical Society}

Sigalas, M.M.; Biswas, R.; Ho, K.M.; Soukoulis, C.M. [Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)] [Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Crouch, D.D. [Advanced Electromagnetic Technologies Center, Raytheon Corporation, Rancho Cucamonga, California 91729 (United States)] [Advanced Electromagnetic Technologies Center, Raytheon Corporation, Rancho Cucamonga, California 91729 (United States)

1999-08-01T23:59:59.000Z

62

Analysis of plasma-magnetic photonic crystal with a tunable band gap  

SciTech Connect (OSTI)

In this paper, electromagnetic wave propagation through the one-dimensional plasma-magnetic photonic crystal in the presence of external magnetic field has been analyzed. The dispersion relation, transmission and reflection coefficients have been obtained by using the transfer matrix method. It is investigated how photonic band gap of photonic crystals will be tuned when both dielectric function {epsilon} and magnetic permeability {mu} of the constitutive materials, depend on applied magnetic field. This is shown by one dimensional photonic crystals consisting of plasma and ferrite material layers stacked alternately.

Mehdian, H.; Mohammadzahery, Z.; Hasanbeigi, A. [Department of Physics and Plasma Research Institute of Tarbiat Moallem University, 49 Dr Mofatteh Avenue, Tehran 15614 (Iran, Islamic Republic of)

2013-04-15T23:59:59.000Z

63

Direct space-time observation of pulse tunneling in an electromagnetic band gap  

SciTech Connect (OSTI)

We present space-time-resolved measurements of electromagnetic pulses tunneling through a coaxial electromagnetic band gap structure. The results show that during the tunneling process the field distribution inside the barrier is an exponentially decaying standing wave whose amplitude increases and decreases as it slowly follows the temporal evolution of the input pulse. At no time is a pulse maximum found inside the barrier, and hence the transmitted peak is not the incident peak that has propagated to the exit. The results support the quasistatic interpretation of tunneling dynamics and confirm that the group delay is not the traversal time of the input pulse peak.

Doiron, Serge; Hache, Alain [Department de physique et d'astronomie, Universite de Moncton, Moncton, New Brunswick, E1A 3E9 (Canada); Winful, Herbert G. [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan 48109-2122 (United States)

2007-08-15T23:59:59.000Z

64

Band gap corrections for molecules and solids using Koopmans theorem and Wannier functions  

E-Print Network [OSTI]

We have proposed a method for correcting the Kohn-Sham eigen energies in the density functional theory (DFT) based on the Koopmans theorem using Wannier functions. The method provides a general approach applicable for molecules and solids for electronic structure calculations. It does not have any adjustable parameters and the computational cost is at the DFT level. For solids, the calculated eigen energies agree well with the experiments for not only the band gaps, but also the energies of other valence and conduction bands. For molecules, the calculated eigen energies agree well with the experimental ionization potentials and electron affinities, and show better trends than the traditional Delta-self-consistent-field (?SCF) results.

Ma, Jie

2015-01-01T23:59:59.000Z

65

Effects of surface termination on the band gap of ultrabright Si29 nanoparticles: Experiments and computational models  

E-Print Network [OSTI]

Effects of surface termination on the band gap of ultrabright Si29 nanoparticles: Experiments constituting a H-terminated reconstructed Si surface was recently proposed as a structural prototype termination with a N linkage in butylamine and O linkage in pentane . The emission band for N-termination

Braun, Paul

66

Periodic dielectric structure for production of photonic band gap and devices incorporating the same  

DOE Patents [OSTI]

A periodic dielectric structure which is capable of producing a photonic band gap and which is capable of practical construction. The periodic structure is formed of a plurality of layers, each layer being formed of a plurality of rods separated by a given spacing. The material of the rods contrasts with the material between the rods to have a refractive index contrast of at least two. The rods in each layer are arranged with their axes parallel and at a given spacing. Adjacent layers are rotated by 90.degree., such that the axes of the rods in any given layer are perpendicular to the axes in its neighbor. Alternating layers (that is, successive layers of rods having their axes parallel such as the first and third layers) are offset such that the rods of one are about at the midpoint between the rods of the other. A four-layer periocity is thus produced, and successive layers are stacked to form a three-dimensional structure which exhibits a photonic band gap. By virtue of forming the device in layers of elongate members, it is found that the device is susceptible of practical construction.

Ho, Kai-Ming (Ames, IA); Chan, Che-Ting (Ames, IA); Soukoulis, Costas (Ames, IA)

1994-08-02T23:59:59.000Z

67

LETTER Communicated by Donald Spencer Wide-Band Information Transmission at the Calyx of Held  

E-Print Network [OSTI]

LETTER Communicated by Donald Spencer Wide-Band Information Transmission at the Calyx of Held, University of Leicester, Leicester LE1 9HN, U.K. Bruce P. Graham b.graham@cs.stir.ac.uk Computing Science and Mathematics, University of Stirling, Stirling FK9 4LA, U.K. We use a mathematical model of the calyx of Held

Graham, Bruce

68

Synchronous Ultra-Wide Band Wireless Sensors Networks for oil and gas exploration  

E-Print Network [OSTI]

Synchronous Ultra-Wide Band Wireless Sensors Networks for oil and gas exploration Stefano Savazzi1 of new oil and gas reservoir. Seismic exploration requires a large number (500 Ă· 2000 nodes, MAC and network layer to develop wireless sensors networks tailored for oil (and gas) exploration

Savazzi, Stefano

69

Here, we present the fabrication and use of plastic Photonic Band Gap Bragg fibres in photonic textiles for applications in  

E-Print Network [OSTI]

Here, we present the fabrication and use of plastic Photonic Band Gap Bragg fibres in photonic­section, Bragg fibres feature periodic sequence of layers of two distinct plastics. Under ambient illumination SCHICKER2 , NING GUO1 , CHARLES DUBOIS3 , RACHEL WINGFIELD2 & MAKSIM SKOROBOGATIY1 COLOUR-ON-DEMAND

Skorobogatiy, Maksim

70

Absorption of Narrow-Gap HgCdTe Near the Band Edge Including Nonparabolicity and the Urbach Tail  

E-Print Network [OSTI]

Absorption of Narrow-Gap HgCdTe Near the Band Edge Including Nonparabolicity and the Urbach Tail, USA. 6.--e-mail: yonchang@uic.edu An analytical model describing the absorption behavior of Hg1-x. This model smoothly fits experimental absorption coefficients over energies ranging from the Urbach tail

Flatte, Michael E.

71

Photovoltaic devices with low band gap polymers Eva Bundgaarda, Sean Shaheenb, David S. Ginleyb, Frederik C. Krebsa  

E-Print Network [OSTI]

Photovoltaic devices with low band gap polymers Eva Bundgaarda, Sean Shaheenb, David S. Ginleyb, Colorado, USA Abstract Progress in organic photovoltaic devices has recently resulted in reported temperature, active area of the device and molecular weight of the polymer, on the photovoltaic response

72

Band gap tuning in GaN through equibiaxial in-plane strains S. K. Yadav,2  

E-Print Network [OSTI]

in photovoltaics and light emission diodes LEDs . The InGaN system has been intensively studied during the past to the large atomic size mismatch between Ga and In.3 Thus, other methods to tune the band gap are needed for potential appli- cations of GaN and related materials systems. It is well-known that the structure

Alpay, S. Pamir

73

Predicting New TiO2 Phases with Low Band Gaps by a Multiobjective Global Optimization Approach  

E-Print Network [OSTI]

stable. This is equivalent to a global optimization problem of a biobjective function, i.e., total energyPredicting New TiO2 Phases with Low Band Gaps by a Multiobjective Global Optimization Approach Hou as a novel global optimization algorithm to predict new polymorphs of bulk TiO2 with better optical

Gong, Xingao

74

Gallium arsenide-based ternary compounds and multi-band-gap solar cell research  

SciTech Connect (OSTI)

Aim of this contract is the achievement of a high-efficiency, low-cost solar cell. The basic approach to the problem is centered upon the heteroepitaxial growth of a III-V compound material onto a single-crystal silicon wafer. The growth technique employed is metalorganic chemical vapor deposition. The silicon wafer may serve as a mechanical substrate and ohmic contact for a single-junction device, or may contain a p-n junction of its own and form the bottom cell of a two junction tandem solar cell structure. The III-V material for the single-junction case is GaAs and for the two-junction case is either GaAlAs or GaAsP, either material having the proper composition to yield a band gap of approximately 1.7 eV. Results achieved in this contract include the following: (1) a 17.6% efficient GaAs-on-Si solar cell; (2) an 18.5% efficient GaAs-on-Si concentrator solar cell at 400 suns; (3) a 24.8% efficient GaAs-on-GaAs solar cell; (4) a 28.7% efficient GaAs-on-GaAs concentrator solar cell at 200 suns; (5) measurement of the effects of dislocation density and emitter doping on GaAs cells; and (6) improvements in the growth process to achieve reproducible thin AlGaAs window layers with low recombination velocities and environmental stability.

Vernon, S. (Spire Corp., Bedford, MA (United States))

1993-02-01T23:59:59.000Z

75

Double Wall Carbon Nanotubes for Wide-Band, Ultrafast Pulse Generation  

E-Print Network [OSTI]

Accepted Manuscript: ACS Nano, 2014, 8 (5), pp 4836–4847DOI: 10.1021/nn500767b 1 Double Wall Carbon Nanotubes for Wide-Band, Ultrafast Pulse Generation Tawfique Hasan1,*, Zhipei Sun2, PingHeng Tan3, Daniel Popa1, Emmanuel Flahaut4,5, Edmund J. R... , Polymer Composites, Saturable Absorber, Ultrafast Laser. Accepted Manuscript: ACS Nano, 2014, 8 (5), pp 4836–4847DOI: 10.1021/nn500767b 2 ABSTRACT: We demonstrate wideband ultrafast optical pulse generation at 1, 1.5 and 2?m using a single polymer...

Hasan, Tawfique; Sun, Zhipei; Tan, PingHeng; Popa, Daniel; Flahaut, Emmanuel; Kelleher, Edmund J. R.; Bonaccorso, Francesco; Wang, Fengqiu; Jiang, Zhe; Torrisi, Felice; Privitera, Giulia; Nicolosi, Valeria; Ferrari, Andrea C.

2014-04-15T23:59:59.000Z

76

SPECTROSCOPIE DE DEFAUTS -LUMINESCENCE I. THE ANALYSIS OF WIDE BAND GAP SEMICONDUCTORS  

E-Print Network [OSTI]

'impuretes donneurs, accepteurs et pieges isoelectroniques,et de leur extension a I'identification d'espkces chimiques of impurity, donors, acceptors and isoelectronic traps, and their extension to the identification of chemical junctions with quite heavy doping to provide the desired high bulk conduc- tivity, certainly in the 10'' cm

Boyer, Edmond

77

Wide-band-gap, alkaline-earth-oxide semiconductor and devices utilizing same  

DOE Patents [OSTI]

This invention relates to novel and comparatively inexpensive semiconductor devices utilizing semiconducting alkaline-earth-oxide crystals doped with alkali metal. The semiconducting crystals are produced by a simple and relatively inexpensive process. As a specific example, a high-purity lithium-doped MgO crystal is grown by conventional techniques. The crystal then is heated in an oxygen-containing atmosphere to form many [Li].degree. defects therein, and the resulting defect-rich hot crystal is promptly quenched to render the defects stable at room temperature and temperatures well above the same. Quenching can be effected conveniently by contacting the hot crystal with room-temperature air.

Abraham, Marvin M. (Oak Ridge, TN); Chen, Yok (Oak Ridge, TN); Kernohan, Robert H. (Oak Ridge, TN)

1981-01-01T23:59:59.000Z

78

Alternative Wide-Band-Gap Materials for Gamma-Ray Spectroscopy  

E-Print Network [OSTI]

Engineering and Radiological Sciences) in The University of Michigan 2013 Doctoral Committee: Professor Zhong emotionally, physically, spiritually, and intellectually through every moment of my graduate school career, the Orion group would not be successful without the great work of his graduate students. It has been a truly

He, Zhong

79

Quasiparticle band structure and density-functional theory: Single-particle excitations and band gaps in lattice models  

E-Print Network [OSTI]

ARTICLES Quasiparticle band structure and density-functional theory: Single-particle excitations-particle eigenvalues. Without rigorous basis even for the exact density-functional theory , these are often taken, eigenvalues obtained from density-functional theory DFT , and those from a corresponding LDA. Notable among

Hess, Daryl W.

80

Designing double-gap linear accelerators for a wide mass range  

SciTech Connect (OSTI)

For applications like ion implantation, rf linacs using double-gap structures with external resonators can be used because they are practical at low frequencies. However, since the two gaps associated with a given resonator cannot be individually phased, it is not obvious how to build a linac that can efficiently accelerate particles having different mass/charge ratios. This paper describes the beam dynamics of double-gap rf linacs and shows how to maximize the range of mass/charge ratios. The theory also tells one how to rescale a linac tune (i.e., reset the voltages and phases) so that a new particle, having a different mass or charge, will behave similarly to the original particle.

Lysenko, W.P.; Wadlinger, E.A.; Rusnak, B.; Krawczyk, F. [Los Alamos National Lab., NM (United States); Saadatmand, K.; Wan, Z. [Eaton Corp., Beverly, MA (United States)

1998-12-31T23:59:59.000Z

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


81

Channelization architecture for wide-band slow light in atomic vapors  

E-Print Network [OSTI]

We propose a ``channelization'' architecture to achieve wide-band electromagnetically induced transparency (EIT) and ultra-slow light propagation in atomic Rb-87 vapors. EIT and slow light are achieved by shining a strong, resonant ``pump'' laser on the atomic medium, which allows slow and unattenuated propagation of a weaker ``signal'' beam, but only when a two-photon resonance condition is satisfied. Our wideband architecture is accomplished by dispersing a wideband signal spatially, transverse to the propagation direction, prior to entering the atomic cell. When particular Zeeman sub-levels are used in the EIT system, then one can introduce a magnetic field with a linear gradient such that the two-photon resonance condition is satisfied for each individual frequency component. Because slow light is a group velocity effect, utilizing differential phase shifts across the spectrum of a light pulse, one must then introduce a slight mismatch from perfect resonance to induce a delay. We present a model which accounts for diffusion of the atoms in the varying magnetic field as well as interaction with levels outside the ideal three-level system on which EIT is based. We find the maximum delay-bandwidth product decreases with bandwidth, and that delay-bandwidth product ~1 should be achievable with bandwidth ~50 MHz (~5 ns delay). This is a large improvement over the ~1 MHz bandwidths in conventional slow light systems and could be of use in signal processing applications.

Zachary Dutton; Mark Bashkansky; Michael Steiner; John Reintjes

2005-10-20T23:59:59.000Z

82

Multi-junction, monolithic solar cell using low-band-gap materials lattice matched to GaAs or Ge  

DOE Patents [OSTI]

A multi-junction, monolithic, photovoltaic solar cell device is provided for converting solar radiation to photocurrent and photovoltage with improved efficiency. The solar cell device comprises a plurality of semiconductor cells, i.e., active p/n junctions, connected in tandem and deposited on a substrate fabricated from GaAs or Ge. To increase efficiency, each semiconductor cell is fabricated from a crystalline material with a lattice constant substantially equivalent to the lattice constant of the substrate material. Additionally, the semiconductor cells are selected with appropriate band gaps to efficiently create photovoltage from a larger portion of the solar spectrum. In this regard, one semiconductor cell in each embodiment of the solar cell device has a band gap between that of Ge and GaAs. To achieve desired band gaps and lattice constants, the semiconductor cells may be fabricated from a number of materials including Ge, GaInP, GaAs, GaInAsP, GaInAsN, GaAsGe, BGaInAs, (GaAs)Ge, CuInSSe, CuAsSSe, and GaInAsNP. To further increase efficiency, the thickness of each semiconductor cell is controlled to match the photocurrent generated in each cell. To facilitate photocurrent flow, a plurality of tunnel junctions of low-resistivity material are included between each adjacent semiconductor cell. The conductivity or direction of photocurrent in the solar cell device may be selected by controlling the specific p-type or n-type characteristics for each active junction.

Olson, Jerry M. (Lakewood, CO); Kurtz, Sarah R. (Golden, CO); Friedman, Daniel J. (Lakewood, CO)

2001-01-01T23:59:59.000Z

83

Partial frequency band gap in one-dimensional magnonic crystals M. Kostylev,1,a  

E-Print Network [OSTI]

approach. It is shown that, due to the one-dimensional artificial periodicity of the medium, the gaps with the artificial spatial periodicity of the structure. In this work, by measuring the frequencies of collective on a silicon substrate using deep ultraviolet lithography with 248 nm exposure wavelength followed by a lift

Adeyeye, Adekunle

84

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 4, 2005 5 A Compact Wide-band EBG Structure Utilizing  

E-Print Network [OSTI]

circuits can provide significant isolation. Transmission line theory developed in [9] is applied to obtainB isolation over 25% bandwidth. The analytical results evaluated based on the transmission line theory the bandgap behavior. To design a compact wide-band EBG, a structure constructed of three layers of ERC, each

Sarabandi, Kamal

85

480 IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 12, NO. 5, MAY 2000 Coupled Structure for Wide-Band EDFA with Gain  

E-Print Network [OSTI]

480 IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 12, NO. 5, MAY 2000 Coupled Structure for Wide applications due to the maturity of the supporting technologies such as the host material and pump sources-band EDFA's [4], [5], we have suggested a structure that recycles useless backward amplified spontaneous

Park, Namkyoo

86

PHYSICAL REVIEW B 90, 115209 (2014) Computational search for direct band gap silicon crystals  

E-Print Network [OSTI]

abundance, silicon is the preferred solar-cell material despite the fact that current silicon materials have semiconductor. For this reason, the most widely used solar-cell materials are all silicon based [1]. Current

Lee, Jooyoung

87

Significant Reduction in NiO Band Gap upon Formation of LixNi1?xO Alloys: Applications to Solar Energy Conversion  

SciTech Connect (OSTI)

Long-term sustainable solar energy conversion relies on identifying economical and versatile semiconductor materials with appropriate band structures for photovoltaic and photocatalytic applications (e.g., band gaps of ?1.5–2.0 eV). Nickel oxide (NiO) is an inexpensive yet highly promising candidate. Its charge-transfer character may lead to longer carrier lifetimes needed for higher efficiencies, and its conduction band edge is suitable for driving hydrogen evolution via water-splitting. However, NiO’s large band gap (?4 eV) severely limits its use in practical applications. Our first-principles quantum mechanics calculations show band gaps dramatically decrease to ?2.0 eV when NiO is alloyed with Li2O. We show that LixNi1?xO alloys (with x=0.125 and 0.25) are p-type semiconductors, contain states with no impurity levels in the gap and maintain NiO’s desirable charge-transfer character. Lastly, we show that the alloys have potential for photoelectrochemical applications, with band edges well-placed for photocatalytic hydrogen production and CO2 reduction, as well as in tandem dye-sensitized solar cells as a photocathode.

Alidoust, Nima; Toroker, Maytal; Keith, John A.; Carter, Emily A.

2014-01-01T23:59:59.000Z

88

Physics of band-gap formation and its evolution in the pillar-based phononic crystal structures  

SciTech Connect (OSTI)

In this paper, the interplay of Bragg scattering and local resonance is theoretically studied in a phononic crystal (PnC) structure composed of a silicon membrane with periodic tungsten pillars. The comparison of phononic band gaps (PnBGs) in three different lattice types (i.e., square, triangular, and honeycomb) with different pillar geometries shows that different PnBGs have varying degrees of dependency on the lattice symmetry based on the interplay of the local resonances and the Bragg effect. The details of this interplay is discussed. The significance of locally resonating pillars, specially in the case of tall pillars, on PnBGs is discussed and verified by examining the PnBG position and width in perturbed lattices via Monte Carlo simulations. It is shown that the PnBGs caused by the local resonance of the pillars are more resilient to the lattice perturbations than those caused by Bragg scattering.

Pourabolghasem, Reza; Mohammadi, Saeed; Eftekhar, Ali Asghar; Adibi, Ali [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Khelif, Abdelkrim [Institut FEMTO-ST, Université de Franche-Comté, CNRS, 32 Avenue de l'Observatoire, 25044 Besançon Cedex (France)

2014-07-07T23:59:59.000Z

89

Conductivity and optical band gaps of polyethylene oxide doped with Li{sub 2}SO{sub 4} salt  

SciTech Connect (OSTI)

The conductivity and optical properties of Li{sub 2}SO{sub 4} doped polyethylene oxide (PEO) films were studied. The polymer electrolyte films are prepared using solution casting technique. The material phase change was confirmed by X-ray diffraction (XRD) technique. Optical absorption study was conducted using UV- Vis. Spectroscopy in the wavelength range 190–1100nm on pure and doped PEO films. The direct and indirect optical band gaps were found decreased from 5.81–4.51eV and 4.84–3.43eV respectively with increasing the Li{sub 2}SO{sub 4}. The conductivity found to increases with increasing the dopant concentration due to strong hopping mechanism at room temperature.

Chapi, Sharanappa, E-mail: dehu2010@gmail.com; Raghu, S., E-mail: dehu2010@gmail.com; Subramanya, K., E-mail: dehu2010@gmail.com; Archana, K., E-mail: dehu2010@gmail.com; Mini, V., E-mail: dehu2010@gmail.com; Devendrappa, H., E-mail: dehu2010@gmail.com [Dept. of Physics, Mangalore University, Mangalagangothri-574199 (India)

2014-04-24T23:59:59.000Z

90

Investigation of anisotropic photonic band gaps in three-dimensional magnetized plasma photonic crystals containing the uniaxial material  

SciTech Connect (OSTI)

In this paper, the dispersive properties of three-dimensional (3D) magnetized plasma photonic crystals (MPPCs) composed of anisotropic dielectric (the uniaxial material) spheres immersed in homogeneous magnetized plasma background with face-centered-cubic (fcc) lattices are theoretically investigated by the plane wave expansion method, as the Voigt effects of magnetized plasma are considered. The equations for calculating the anisotropic photonic band gaps (PBGs) in the first irreducible Brillouin zone are theoretically deduced. The anisotropic PBGs and two flatbands regions can be obtained. The effects of the ordinary-refractive index, extraordinary-refractive index, filling factor, plasma frequency, and external magnetic field on the dispersive properties of the 3D MPPCs are investigated in detail, respectively, and some corresponding physical explanations are also given. The numerical results show that the anisotropy can open partial band gaps in 3D MPPCs with fcc lattices and the complete PBGs can be found compared to the conventional 3D MPPCs doped by the isotropic material. The bandwidths of PBGs can be tuned by introducing the magnetized plasma into 3D PCs containing the uniaxial material. It is also shown that the anisotropic PBGs can be manipulated by the ordinary-refractive index, extraordinary-refractive index, filling factor, plasma frequency, and external magnetic field, respectively. The locations of flatbands regions cannot be manipulated by any parameters except for the plasma frequency and external magnetic field. Introducing the uniaxial material can obtain the complete PBGs as the 3D MPPCs with high symmetry and also provides a way to design the tunable devices.

Zhang, Hai-Feng [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China) [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Nanjing Artillery Academy, Nanjing 211132 (China)] [China; Liu, Shao-Bin; Kong, Xiang-Kun [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)] [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

2013-09-15T23:59:59.000Z

91

Band-gap nonlinear optical generation: The structure of internal optical field and the structural light focusing  

SciTech Connect (OSTI)

A novel approach for the enhancement of nonlinear optical effects inside globular photonic crystals (PCs) is proposed and systematically studied via numerical simulations. The enhanced optical harmonic generation is associated with two- and three-dimensional PC pumping with the wavelength corresponding to different PC band-gaps. The interactions between light and the PC are numerically simulated using the finite-difference time-domain technique for solving the Maxwell's equations. Both empty and infiltrated two-dimensional PC structures are considered. A significant enhancement of harmonic generation is predicted owing to the highly efficient PC pumping based on the structural light focusing effect inside the PC structure. It is shown that a highly efficient harmonic generation could be attained for both the empty and infiltrated two- and three-dimensional PCs. We are demonstrating the ability for two times enhancement of the parametric decay efficiency, one order enhancement of the second harmonic generation, and two order enhancement of the third harmonic generation in PC structures in comparison to the nonlinear generations in appropriate homogenous media. Obviously, the nonlinear processes should be allowed by the molecular symmetry. The criteria of the nonlinear process efficiency are specified and calculated as a function of pumping wavelength position towards the PC globule diameter. Obtained criterion curves exhibit oscillating characteristics, which indicates that the highly efficient generation corresponds to the various PC band-gap pumping. The highest efficiency of nonlinear conversions could be reached for PC pumping with femtosecond optical pulses; thus, the local peak intensity would be maximized. Possible applications of the observed phenomenon are also discussed.

Zaytsev, Kirill I., E-mail: kirzay@gmail.com; Katyba, Gleb M.; Yakovlev, Egor V.; Yurchenko, Stanislav O., E-mail: st.yurchenko@mail.ru [Bauman Moscow State Technical University, 2nd Baumanskaya str. 5, Moscow 105005 (Russian Federation); Gorelik, Vladimir S. [P. N. Lebedev Physics Institute of the Russian Academy of Sciences, Leninskiy Prospekt 53, Moscow 119991 (Russian Federation)

2014-06-07T23:59:59.000Z

92

New multi-rod linear actuator for direct-drive, wide mechanical band pass  

E-Print Network [OSTI]

(e.g. gears). This mechanical transmission is required in order to adapt the load to a standard motor), · reducing noise, · increasing movement control, · widening the mechanical band pass, · lowering maintenance. For automation applications, such as command (plane command, hard disk harm) or regulation (vibration

Boyer, Edmond

93

Adaptive algorithms for QCSE optical modulators Excitonic optical absorption at near band gap photon energies in III-V compound semiconductor  

E-Print Network [OSTI]

. Typically, such designs make use of simple rectangular potential wells in the AlGaAs/GaAs or InP/InGaAsP1 Adaptive algorithms for QCSE optical modulators Excitonic optical absorption at near band gap of the quantum well, the excitonic optical absorption strength and energy can be manipulated. This quantum

Levi, Anthony F. J.

94

On the sub-band gap optical absorption in heat treated cadmium sulphide thin film deposited on glass by chemical bath deposition technique  

SciTech Connect (OSTI)

The sub-band gap optical absorption in chemical bath deposited cadmium sulphide thin films annealed at different temperatures has been critically analyzed with special reference to Urbach relation. It has been found that the absorption co-efficient of the material in the sub-band gap region is nearly constant up to a certain critical value of the photon energy. However, as the photon energy exceeds the critical value, the absorption coefficient increases exponentially indicating the dominance of Urbach rule. The absorption coefficients in the constant absorption region and the Urbach region have been found to be sensitive to annealing temperature. A critical examination of the temperature dependence of the absorption coefficient indicates two different kinds of optical transitions to be operative in the sub-band gap region. After a careful analyses of SEM images, energy dispersive x-ray spectra, and the dc current-voltage characteristics, we conclude that the absorption spectra in the sub-band gap domain is possibly associated with optical transition processes involving deep levels and the grain boundary states of the material.

Chattopadhyay, P.; Karim, B.; Guha Roy, S. [Department of Electronic Science, University of Calcutta, 92, A.P.C. Road, Kolkata 700009 (India)

2013-12-28T23:59:59.000Z

95

Size-dependent shifts of the Néel temperature and optical band-gap in NiO nanoparticles  

SciTech Connect (OSTI)

Bulk NiO is a well-known antiferromagnet with Neel temperature T{sub N}(?)?=?524?K and an optical band-gap E{sub g}?=?4.3?eV. With decrease in particle size D from 40?nm to 4?nm of NiO, systematic changes of T{sub N} and E{sub g} are observed and discussed here. From magnetic measurements, the changes in T{sub N} with D are found to fit finite-size scaling equation T{sub N}(D)?=?T{sub N}(?) [1 ? (?{sub o}/D){sup ?}] with ??=?3.2?±?0.5 and ?{sub o}?=?3.2?±?0.2?nm, in good agreement with the predictions for a Heisenberg system. The observed blue shifts of E{sub g} with decrease in D reaching E{sub g}?=?5.12?eV for D???4?nm are likely due to quantum confinement and non-stoichiometry.

Thota, Subhash, E-mail: mseehra@wvu.edu, E-mail: subhasht@iitg.ac.in [Department of Physics, Indian Institute of Technology, Guwahati, Assam 781039 (India); Shim, J. H.; Seehra, M. S., E-mail: mseehra@wvu.edu, E-mail: subhasht@iitg.ac.in [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States)

2013-12-07T23:59:59.000Z

96

Toward Photochemical Water Splitting Using Band-Gap-Narrowed Semiconductors and Transition-Metal Based Molecular Catalysts  

SciTech Connect (OSTI)

We are carrying out coordinated theoretical and experimental studies of toward photochemical water splitting using band-gap-narrowed semiconductors (BGNSCs) with attached multi-electron molecular water oxidation and hydrogen production catalysts. We focus on the coupling between the materials properties and the H{sub 2}O redox chemistry, with an emphasis on attaining a fundamental understanding of the individual elementary steps in the following four processes: (1) Light-harvesting and charge-separation of stable oxide or oxide-derived semiconductors for solar-driven water splitting, including the discovery and characterization of the behavior of such materials at the aqueous interface; (2) The catalysis of the four-electron water oxidation by dinuclear hydroxo transition-metal complexes with quinonoid ligands, and the rational search for improved catalysts; (3) Transfer of the design principles learned from the elucidation of the DuBois-type hydrogenase model catalysts in acetonitrile to the rational design of two-electron hydrogen production catalysts for aqueous solution; (4) Combining these three elements to examine the function of oxidation catalysts on BGNSC photoanode surfaces and hydrogen production catalysts on cathode surfaces at the aqueous interface to understand the challenges to the efficient coupling of the materials functions.

Muckerman,J.T.; Rodriguez, J.A.; Fujita, E.

2009-06-07T23:59:59.000Z

97

The Oxford-Dartmouth Thirty Degree Survey I: Observations and Calibration of a Wide-Field Multi-Band Survey  

E-Print Network [OSTI]

The Oxford Dartmouth Thirty Degree Survey (ODTS) is a deep, wide, multi-band imaging survey designed to cover a total of 30 square degrees in BVRi'Z, with a subset of U and K band data, in four separate fields of 5-10 deg^2 centred at 00:18:24 +34:52, 09:09:45 +40:50, 13:40:00 +02:30 and 16:39:30 +45:24. Observations have been made using the Wide Field Camera on the 2.5-m Isaac Newton Telescope in La Palma to average limiting depths (5 sigma Vega, aperture magnitudes) of U=24.8, B=25.6, V=25.0, R=24.6, and i'=23.5, with observations taken in ideal conditions reaching the target depths of U=25.3, B=26.2, V=25.7, R=25.4, and i'=24.6. The INT Z band data was found to be severely effected by fringing and, consequently, is now being obtained at the MDM observatory in Arizona. A complementary K-band survey has also been carried out at MDM, reaching an average depth of K_{5\\sigma}~18.5. At present, approximately 23 deg^2 of the ODTS have been observed, with 3.5 deg^2 of the K band survey completed. This paper details the survey goals, field selection, observation strategy and data reduction procedure, focusing on the photometric calibration and catalogue construction. Preliminary photometric redshifts have been obtained for a subsample of the objects with R <= 23. These results are presented alongside a brief description of the photometric redshift determination technique used. The median redshift of the survey is estimated to be z~0.7 from a combination of the ODTS photometric redshifts and comparison with the redshift distributions of other surveys. Finally, galaxy number counts for the ODTS are presented which are found to be in excellent agreement with previous studies.

Emily C. MacDonald; Paul Allen; Gavin Dalton; Leonidas A. Moustakas; Catherine Heymans; Edward Edmondson; Chris Blake; Lee Clewley; Molly C. Hammell; Ed Olding; Lance Miller; Steve Rawlings; Jasper Wall; Gary Wegner; Christian Wolf; .

2004-05-11T23:59:59.000Z

98

Visible-light absorption and large band-gap bowing of GaN1-xSbx from first principles  

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

Applicability of the Ga(Sbx)N1-x alloys for practical realization of photoelectrochemical water splitting is investigated using first-principles density functional theory incorporating the local density approximation and generalized gradient approximation plus the Hubbard U parameter formalism. Our calculations reveal that a relatively small concentration of Sb impurities is sufficient to achieve a significant narrowing of the band gap, enabling absorption of visible light. Theoretical results predict that Ga(Sbx)N1-x alloys with 2-eV band gaps straddle the potential window at moderate to low pH values, thus indicating that dilute Ga(Sbx)N1-x alloys could be potential candidates for splitting water under visible light irradiation.

Sheetz, R. Michael; Richter, Ernst; Andriotis, Antonis N.; Lisenkov, Sergey; Pendyala, Chandrashekhar; Sunkara, Mahendra K.; Menon, Madhu

2011-08-01T23:59:59.000Z

99

zBootes : z-band Photometry in the NOAO Deep Wide-Field Survey Bootes Field  

E-Print Network [OSTI]

We present zBootes, a new z-band photometric imaging campaign of 7.62 square degrees in the NOAO Deep Wide-Field Survey (NDWFS) Bootes field. In this paper, all of the images for this survey are released as well as the associated catalogs. The final zBootes catalogs are complete (at the 50% level) to 22.7 mag over 50% of the field. With these depths, the zBootes images should be sensitive to L* galaxies to z~1 over much of the survey area. These data have several possible applications including searching for and characterizing high-redshift quasars and brown dwarfs and providing added constraints to photometric redshift determinations of galaxies and active galaxies to moderate redshift. The zBootes imaging adds photometric data at a new wavelength to the existing wealth of multi-wavelength observations of the NDWFS Bootes field.

Richard J. Cool

2006-11-16T23:59:59.000Z

100

PHYSICAL REVIEW B 85, 155101 (2012) Electronic properties of layered multicomponent wide-band-gap oxides: A combinatorial approach  

E-Print Network [OSTI]

devices including solar cells, smart windows, and flat panel displays, and they also find application as heating, antistatic, and optical coatings (for select reviews, see Refs. 1­7). Multicomponent TCOs

Medvedeva, Julia E.

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


101

PHYSICAL REVIEW B 86, 085123 (2012) Composition-dependent oxygen vacancy formation in multicomponent wide-band-gap oxides  

E-Print Network [OSTI]

PHYSICAL REVIEW B 86, 085123 (2012) Composition-dependent oxygen vacancy formation University of Science and Technology, Rolla, Missouri 65409, USA (Received 17 April 2012; revised manuscript received 19 July 2012; published 16 August 2012) The formation and distribution of oxygen vacancy

Medvedeva, Julia E.

102

Structure and red shift of optical band gap in CdO–ZnO nanocomposite synthesized by the sol gel method  

SciTech Connect (OSTI)

The structure and the optical band gap of CdO–ZnO nanocomposites were studied. Characterization using X-ray diffraction (XRD), transmission electron microscopy (TEM) and diffuse reflectance spectroscopy (DRS) analysis confirms that CdO phase is present in the nanocomposites. TEM analysis confirms the formation of spheroidal nanoparticles and nanorods. The particle size was calculated from Debey–Sherrer?s formula and corroborated by TEM images. FTIR spectroscopy shows residual organic materials (aromatic/Olefinic carbon) from nanocomposites surface. CdO content was modified in the nanocomposites in function of polyvinylalcohol (PVA) added. The optical band gap is found to be red shift from 3.21 eV to 3.11 eV with the increase of CdO content. Photoluminescence (PL) measurements reveal the existence of defects in the synthesized CdO–ZnO nanocomposites. - Graphical abstract: Optical properties of ZnO, CdO and ZnO/CdO nanoparticles. Display Omitted - Highlights: • TEM analysis confirms the presence of spherical nanoparticles and nanorods. • The CdO phase is present in the nanocomposites. • The band gap of the CdO–ZnO nanocomposites is slightly red shift with CdO content. • PL emission of CdO–ZnO nanocomposite are associated to structural defects.

Mosquera, Edgar, E-mail: edemova@ing.uchile.cl [Laboratorio de Materiales a Nanoescala, Departamento de Ciencia de los Materiales, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Av. Tupper 2069, Santiago (Chile); Pozo, Ignacio del, E-mail: ignacio.dpf@gmail.com [Facultad de Ciencias Naturales, Matemáticas y del Medio Ambiente, Universidad Tecnológica Metropolitana, Av. José Pedro Alessandri 1242, Santiago (Chile); Morel, Mauricio, E-mail: mmorel@ing.uchile.cl [Laboratorio de Materiales a Nanoescala, Departamento de Ciencia de los Materiales, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Av. Tupper 2069, Santiago (Chile)

2013-10-15T23:59:59.000Z

103

Negative band gap bowing in epitaxial InAsGaAs alloys and predicted band offsets of the strained binaries and alloys on various substrates  

E-Print Network [OSTI]

Renewable Energy Laboratory, Golden, Colorado 80401 Received 21 December 2001; accepted for publication 26 as an adjustable parameter along with other quantities when measured interband transition energies are fit which relates transition-atom defect levels to an absolute energy reference to infer approximate band

Hart, Gus

104

SIMULATION OF A WIDE-BAND LOW-ENERGY NEUTRINO BEAM FOR VERY LONG BASELINE NEUTRINO OSCILLATION EXPERIMENTS.  

SciTech Connect (OSTI)

We present simulations of a wide-band low-energy neutrino beam for a future very long baseline neutrino oscillation (VLBNO) program using the proton beam from the Main Injector (MI) proton accelerator at Fermi National Accelerator Laboratory (Fermilab). The target and horn designs previously developed for Brookhaven Laboratory's Alternating Gradient Synchrotron (AGS) VLBNO program are used without modifications. The neutrino flux distributions for various MI proton beam energies and new high-intensity neutrino beam-line designs possible at Fermilab are presented. The beam-line siting and design parameters are chosen to match the requirements of an on-axis beam from Fermilab to one of the two possible sites for the future Deep Underground Science and Engineering Laboratory (DUSEL). A preliminary estimate of the observable event rates and spectra at a detector located in DUSEL for different beam configurations has been performed. Our preliminary conclusions are that a 40-60 GeV 0.5 to 1 MW beam from the Fermilab Main Injector to a DUSEL site has the potential to reach the desired intensity for the next generation of neutrino oscillation experiments. Recent studies indicate that the Fermilab MI can reach a beam power of 0.5 MW at 60 GeV with incremental upgrades to the existing accelerator complex.

BISHAI, M.; HEIM, J.; LEWIS, C.; MARINO, A.D.; VIREN, B.; YUMICEVA, F.

2006-08-01T23:59:59.000Z

105

Theory of non-Markovian decay of a cascade atom in high-Q cavities and photonic band-gap materials  

E-Print Network [OSTI]

The dynamics of a three-level atom in a cascade configuration with both transitions coupled to a single structured reservoir of quantized field modes is treated using Laplace transform methods applied to the coupled amplitude equations. Results are also obtained from master equations by two different approaches, that is, involving either pseudomodes or quasimodes. Two different types of reservoir are considered, namely a high-Q cavity and a photonic band-gap system, in which the respective reservoir structure functions involve Lorentzians. Non-resonant transitions are included in the model. In all cases non-Markovian behaviour for the atomic system can be found, such as oscillatory decay for the high-Q cavity case and population trapping for the photonic band-gap case. In the master equation approaches, the atomic system is augmented by a small number of pseudomodes or quasimodes, which in the quasimode approach themselves undergo Markovian relaxation into a flat reservoir of continuum quasimodes. Results from these methods are found to be identical to those from the Laplace transform method including two-photon excitation of the reservoir with both emitting sequences. This shows that complicated non-Markovian decays of an atomic system into structured EM field reservoirs can be described by Markovian models for the atomic system coupled to a small number of pseudomodes or quasimodes.

B. M. Garraway; B. J. Dalton

2006-02-13T23:59:59.000Z

106

An access etiquette for very-wide wireless bands R. Garcesa,*, J.J. Garcia-Luna-Acevesb  

E-Print Network [OSTI]

, 901 San Antonio Road, Palo Alto, CA 94303, USA d Department of Electrical Engineering, Technion," for the 59­64 GHz unlicensed band to allow systems from different manufacturers with different physical cable. However, equipment may not be operated on this band, until an etiquette has been defined for its

California at Santa Cruz, University of

107

Solar Energy Materials & Solar Cells 91 (2007) 15991610 Improving solar cell efficiency using photonic band-gap materials  

E-Print Network [OSTI]

Solar Energy Materials & Solar Cells 91 (2007) 1599­1610 Improving solar cell efficiency using) solar energy conversion systems (or solar cells) are the most widely used power systems. However and reliable solar-cell devices is presented. We show that due their ability to modify the spectral and angular

Dowling, Jonathan P.

108

Identifying topological-band insulator transitions in silicene and other 2D gapped Dirac materials by means of Rényi-Wehrl entropy  

E-Print Network [OSTI]

We propose a new method to identify transitions from a topological insulator to a band insulator in silicene (the silicon equivalent of graphene) in the presence of perpendicular magnetic and electric fields, by using the R\\'enyi-Wehrl entropy of the quantum state in phase space. Electron-hole entropies display an inversion/crossing behavior at the charge neutrality point for any Landau level, and the combined entropy of particles plus holes turns out to be maximum at this critical point. The result is interpreted in terms of delocalization of the quantum state in phase space. The entropic description presented in this work will be valid in general 2D gapped Dirac materials, with a strong intrinsic spin-orbit interaction, isoestructural with silicene.

M. Calixto; E. Romera

2015-02-11T23:59:59.000Z

109

An Access Etiquette for VeryWide Wireless Bands \\Lambda Rodrigo Garces , J.J. GarciaLunaAceves  

E-Print Network [OSTI]

Alto, CA 94303, USA raphael.rom@eng.sun.com and Department of Electrical Engineering Technion, Israel­64 GHz unlicensed band to allow sys­ tems from different manufacturers with different physical and medium rates currently available to a fixed user through fiber optic cable. How­ ever, equipment may

California at Santa Cruz, University of

110

An Access Etiquette for Very-Wide Wireless Bands Rodrigo Garces , J.J. Garcia-Luna-Aceves  

E-Print Network [OSTI]

Alto, CA 94303, USA raphael.rom@eng.sun.com and Department of Electrical Engineering Technion, Israel," for the ¡£¢ -¤£¥ GHz unlicensed band to allow sys- tems from different manufacturers with different physical and medium. This would extend the data rates currently available to a fixed user through fiber optic cable. How- ever

California at Santa Cruz, University of

111

An Access Etiquette for Very-Wide Wireless Bands Rodrigo Garces , J.J. Garcia-Luna-Aceves  

E-Print Network [OSTI]

, USA raphael.rom@eng.sun.com and Department of Electrical Engineering Technion, Israel Abstract We unlicensed band to allow sys- tems from different manufacturers with different physical and medium rates currently available to a fixed user through fiber optic cable. How- ever, equipment may

Rom, Raphi

112

One-photon band gap engineering of borate glass doped with ZnO for photonics applications  

SciTech Connect (OSTI)

Lithium tungsten borate glass of the composition (0.56-x)B{sub 2}O{sub 3}-0.4Li{sub 2}O-xZnO-0.04WO{sub 3} (0 {<=}x{<=} 0.1 mol. %) is prepared for photonics applications. The glass is doped with ZnO to tune the glass absorption characteristics in a wide spectrum range (200-2500 nm). Chemical bond approach, including chemical structure, electronegativity, bond ionicity, nearest-neighbor coordination, and other chemical bonding aspect, is used to analyze and to explain the obtained glass properties such as: transmittance, absorption, electronic structure parameters (bandgap, Fermi level, and Urbach exciton-phonon coupling), Wannier free excitons excitation (applying Elliott's model), and two-photon absorption coefficient as a result of replacement of B{sub 2}O{sub 3} by ZnO.

Abdel-Baki, Manal [Glass Department, National Research Centre, Dokki 12311 Giza (Egypt); Abdel-Wahab, Fathy A.; El-Diasty, Fouad [Physics Department, Faculty of Science, Ain Shams University, Abbasia, 11566 Cairo (Egypt)

2012-04-01T23:59:59.000Z

113

VOLUME 84, NUMBER 19 P H Y S I C A L R E V I E W L E T T E R S 8 MAY 2000 Theory and Experiments on Elastic Band Gaps  

E-Print Network [OSTI]

Investigaciones CientĂ­ficas (CSIC), Serrano 144, 28006 Madrid, Spain 2 Ames Laboratory, Iowa State University, Ames, Iowa 50011 3 Instituto de AcĂşstica, CSIC, Serrano 144, 28006 Madrid, Spain 4 Instituto de FĂ­sica Aplicada, CSIC, Serrano 144, 28006 Madrid, Spain (Received 26 February 1999) We study elastic band gaps

114

Hybrid density functional calculations of the band gap of GaxIn1-xN Xifan Wu,1 Eric J. Walter,2 Andrew M. Rappe,3 Roberto Car,1 and Annabella Selloni1  

E-Print Network [OSTI]

Hybrid density functional calculations of the band gap of GaxIn1-xN Xifan Wu,1 Eric J. Walter,2 Andrew M. Rappe,3 Roberto Car,1 and Annabella Selloni1 1Chemistry Department, Princeton University Recent theoretical work has provided evidence that hybrid functionals, which include a fraction of exact

Rappe, Andrew M.

115

Band gap of CdTe and Cd{sub 0.9}Zn{sub 0.1}Te crystals  

SciTech Connect (OSTI)

The band gap E{sub g} of the CdTe and Cd{sub 0.9}Zn{sub 0.1}Te crystals and its temperature dependence are determined by optical methods. This is motivated by considerable contradictoriness of the published data, which hampers the interpretation and calculation of characteristics of detectors of X-ray and {gamma} radiation based on these materials (E{sub g} = 1.39-1.54 and 1.51-1.6 eV for CdTe and Cd{sub 0.9}Zn{sub 0.1}Te, respectively). The used procedure of determination of E{sub g} is analyzed from the viewpoint of the influence of the factors leading to inaccuracies in determination of its value. The measurements are performed for well-purified high-quality samples. The acquired data for CdTe (E{sub g} = 1.47-1.48 eV) and Cd{sub 0.9}Zn{sub 0.1}Te (E{sub g} = 1.52-1.53 eV) at room temperature substantially narrow the range of accurate determination of E{sub g}.

Kosyachenko, L. A., E-mail: lakos@chv.ukrpact.net; Sklyarchuk, V. M.; Sklyarchuk, O. V.; Maslyanchuk, O. L. [Chernovtsy National University (Ukraine)

2011-10-15T23:59:59.000Z

116

Band-Gap Reduction and Dopant Interaction in Epitaxial La,Cr Co-doped SrTiO3 Thin Films  

SciTech Connect (OSTI)

We show that by co-doping SrTiO3 (STO) epitaxial thin films with equal amounts of La and Cr it is possible to produce films with an optical band gap ~0.9 eV lower than that of undoped STO. Sr1-xLaxTi1-xCrxO3 thin films were deposited by molecular beam epitaxy and characterized using x-ray photoelectron spectroscopy and x-ray absorption near-edge spectroscopy to show that the Cr dopants are almost exclusively in the Cr3+ oxidation state. Extended x-ray absorption fine structure measurements and theoretical modeling suggest that it is thermodynamically preferred for La and Cr dopants to occupy nearest neighbor A- and B-sites in the lattice. Transport measurements show that the material exhibits variable-range hopping conductivity with high resistivity. These results create new opportunities for the use of doped STO films in photovoltaic and photocatalytic applications.

Comes, Ryan B.; Sushko, Petr; Heald, Steve M.; Colby, Robert J.; Bowden, Mark E.; Chambers, Scott A.

2014-12-03T23:59:59.000Z

117

Gallium arsenide-based ternary compounds and multi-band-gap solar cell research. Annual subcontract report, 15 April 1988--14 June 1990  

SciTech Connect (OSTI)

Aim of this contract is the achievement of a high-efficiency, low-cost solar cell. The basic approach to the problem is centered upon the heteroepitaxial growth of a III-V compound material onto a single-crystal silicon wafer. The growth technique employed is metalorganic chemical vapor deposition. The silicon wafer may serve as a mechanical substrate and ohmic contact for a single-junction device, or may contain a p-n junction of its own and form the bottom cell of a two junction tandem solar cell structure. The III-V material for the single-junction case is GaAs and for the two-junction case is either GaAlAs or GaAsP, either material having the proper composition to yield a band gap of approximately 1.7 eV. Results achieved in this contract include the following: (1) a 17.6% efficient GaAs-on-Si solar cell; (2) an 18.5% efficient GaAs-on-Si concentrator solar cell at 400 suns; (3) a 24.8% efficient GaAs-on-GaAs solar cell; (4) a 28.7% efficient GaAs-on-GaAs concentrator solar cell at 200 suns; (5) measurement of the effects of dislocation density and emitter doping on GaAs cells; and (6) improvements in the growth process to achieve reproducible thin AlGaAs window layers with low recombination velocities and environmental stability.

Vernon, S. [Spire Corp., Bedford, MA (United States)

1993-02-01T23:59:59.000Z

118

Gallium arsenide-based ternary compounds and multi-band-gap solar cell research. Final subcontract report, 1 April 1988--31 March 1990  

SciTech Connect (OSTI)

This report describes work to achieve a high-efficiency, low-cost solar cell. The basic approach to the problem is centered upon the heteroepitaxial growth of a III-V compound material onto a single-crystal silicon wafer. The growth technique employed throughout this work is metal-organic chemical vapor deposition. The silicon wafer may serve as a mechanical substrate and ohmic contact for a single-junction device, or it may contain a p-n junction of its own and form the bottom cell of a two-junction tandem solar cell structure. The III-V material for the single-junction case is GaAs, and for the two-junction case it is either GaAlAs or GaAsP, either material having the proper composition to yield a band gap of approximately 1.7 eV. Results achieved in this contract include (1) a 17.6%-efficient GaAs-on-Si solar cell; (2) an 18.5%-efficient GaAs-on-Si concentrator solar cell at 400 suns; (3) a 24.8%-efficient GaAs-on-GaAs solar cell; (4) a 28.7%-efficient GaAs-on-GaAs concentrator solar cell at 200 suns; (5) the measurement of the effects of dislocation density and emitter doping on GaAs cells; and (6) improvements in the growth process to achieve reproducible thin AlGaAs window layers with low recombination velocities and environmental stability.

Vernon, S. [Spire Corp., Bedford, MA (United States)

1993-07-01T23:59:59.000Z

119

Theoretical study of influencing factors on the dispersion of bulk band-gap edges and the surface states in topological insulators Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3}  

SciTech Connect (OSTI)

The dispersion of the band-gap edge states in bulk topological insulators Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3} is considered within density functional theory. The dependences of this dispersion both on the approximation used for an exchange-correlation functional at fixed unit cell parameters and atomic positions and on these parameters and positions that are obtained upon structural relaxation performed using a certain approximated functional are analyzed. The relative position of the Dirac point of topologically protected surface states and the valence band maximum in the surface electronic structure of the topological insulators is discussed.

Rusinov, I. P., E-mail: rusinovip@gmail.com; Nechaev, I. A. [Tomsk State University (Russian Federation); Chulkov, E. V. [Donostia International Physics Center (DIPC) (Spain)

2013-06-15T23:59:59.000Z

120

CARS: the CFHTLS-Archive-Research Survey; I. Five-band multi-colour data from 37 sq. deg. CFHTLS-Wide observations  

E-Print Network [OSTI]

We present the CFHTLS-Archive-Research Survey (CARS). It is a virtual multi-colour survey based on public archive images from the CFHT-Legacy-Survey. Our main scientific interests in CARS are optical searches for galaxy clusters from low to high redshift and their subsequent study with photometric and weak-gravitational lensing techniques. As a first step of the project we present multi-colour catalogues from 37 sq. degrees of the CFHTLS-Wide component. Our aims are to create astrometrically and photometrically well calibrated co-added images. Second goal are five-band (u*, g', r', i', z') multi-band catalogues with an emphasis on reliable estimates for object colours. These are subsequently used for photometric redshift estimates. The article explains in detail data processing, multi-colour catalogue creation and photometric redshift estimation. Furthermore we apply a novel technique, based on studies of the angular galaxy cross-correlation function, to quantify the reliability of photo-z's. The accuracy of our high-confidence photo-z sample (10-15 galaxies per sq. arcmin) is estimated to $\\sigma_{\\Delta_z/(1+z)}\\approx 0.04-0.05$ up to i'<24 with typically only 1-3% outliers. Interested users can obtain access to our data by request to the authors.

T. Erben; H. Hildebrandt; M. Lerchster; P. Hudelot; J. Benjamin; L. van Waerbeke; T. Schrabback; F. Brimioulle; O. Cordes; J. P. Dietrich; K. Holhjem; M. Schirmer; P. Schneider

2008-11-13T23:59:59.000Z

Note: This page contains sample records for the topic "wide band gap" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


121

Towards Direct-Gap Silicon Phases by the Inverse Band Structure Design Approach H. J. Xiang,1,2,* Bing Huang,2  

E-Print Network [OSTI]

phase with quasidirect gaps of 1.55 eV, which is a promising candidate for making thin-film solar cells have also been based on diamond Si in monocrystalline or large-grained polycrystalline form [1 gap of 1.55 eV. We suggest that these new Si phases could be used in thin-film solar cells

Gong, Xingao

122

Interaction of wide-band-gap single crystals with 248-nm excimer laser radiation. XI. The effect of water vapor and temperature on laser desorption  

E-Print Network [OSTI]

. Significantly, introducing water vapor lowers the particle velocities and thus the effective surface temperature systems, simultaneous electronic excitation and exposure to aggressive chemicals can acceler- ate etching-induced neutral particle desorption and surface erosion on single- crystal sodium chloride in the presence of low

Dickinson, J. Thomas

123

Impact of ion-implantation-induced band gap engineering on the temperature-dependent photoluminescence properties of InAs/InP quantum dashes  

SciTech Connect (OSTI)

We report on the effects of the As/P intermixing induced by phosphorus ion implantation in InAs/InP quantum dashes (QDas) on their photoluminescence (PL) properties. For nonintermixed QDas, usual temperature-dependent PL properties characterized by a monotonic redshift in the emission band and a continual broadening of the PL linewidth as the temperature increases, are observed. For intermediate ion implantation doses, the inhomogeneous intermixing enhances the QDas size dispersion and the enlarged distribution of carrier confining potential depths strongly affects the temperature-dependent PL properties below 180 K. An important redshift in the PL emission band occurs between 10 and 180 K which is explained by a redistribution of carriers among the different intermixed QDas of the ensemble. For higher implantation doses, the homogeneous intermixing reduces the broadening of the localized QDas state distribution and the measured linewidth temperature behavior matches that of the nonintermixed QDas. An anomalous temperature-dependent emission energy behavior has been observed for extremely high implantation doses, which is interpreted by a possible QDas dissolution.

Hadj Alouane, M. H.; Ilahi, B.; Maaref, H. [Laboratoire de Micro-Optoelectronique et Nanostructures (LMON), Faculte des Sciences, Avenue de l'environnement, 5019 Monastir (Tunisia); Salem, B.; Aimez, V.; Morris, D. [Centre de Recherche en Nanofabrication et Nanocaracterisation (CRN2), Universite de Sherbrooke, (Quebec) J1K 2R1 (Canada); Turala, A.; Regreny, P.; Gendry, M. [Institut des Nanotechnologies de Lyon (INL), UMR CNRS 5270, Universite de Lyon, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, F-69134 Ecully (France)

2010-07-15T23:59:59.000Z

124

A Fully Integrated Multi-Band Multi-Output Synthesizer with Wide-Locking-Range 1/3 Injection Locked Divider Utilizing Self-Injection Technique for Multi-Band Microwave Systems  

E-Print Network [OSTI]

This dissertation reports the development of a new multi-band multi-output synthesizer, 1/2 dual-injection locked divider, 1/3 injection-locked divider with phase-tuning, and 1/3 injection-locked divider with self-injection using 0.18-micrometer...

Lee, Sang Hun

2012-10-19T23:59:59.000Z

125

Transformation Optics with Photonic Band Gap Media  

E-Print Network [OSTI]

We introduce a class of optical media based on adiabatically modulated, dielectric-only, and potentially extremely low-loss, photonic crystals. The media we describe represent a generalization of the eikonal limit of transformation optics (TO). The foundation of the concept is the possibility to fit frequency isosurfaces in the k-space of photonic crystals with elliptic surfaces, allowing them to mimic the dispersion relation of light in anisotropic effective media. Photonic crystal cloaks and other TO devices operating at visible wavelengths can be constructed from optically transparent substances like glasses, whose attenuation coefficient can be as small as 10 dB/km, suggesting the TO design methodology can be applied to the development of optical devices not limited by the losses inherent to metal-based, passive metamaterials.

Urzhumov, Yaroslav A

2010-01-01T23:59:59.000Z

126

Minding the Gap Makes for More Efficient Solar Cells  

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

properties of these materials go through a dramatic change that makes them ideal for solar energy applications. These materials can go from indirect band gap semiconductors to...

127

Red band needle blight is an economically important disease affecting a number of coniferous trees, in particular pines. The disease has a world-wide distribution but until recently it was mainly of concern in the southern  

E-Print Network [OSTI]

Red band needle blight is an economically important disease affecting a number of coniferous trees septosporum. Red band needle blight causes premature needle defoliation which results in the loss of timber susceptible species in future rotations. Red band needle blight of conifers in Britain Research Note Anna

128

Energy Gaps in a Spacetime Crystal  

E-Print Network [OSTI]

This paper presents an analysis of the band structure of a spacetime potential lattice created by a standing electromagnetic wave. We show that there are energy band gaps. We estimate the effect, and propose a measurement that could confirm the existence of such phenomena.

L. P. Horwitz; E. Z. Engelberg

2009-11-08T23:59:59.000Z

129

Effects of anneals in ammonia on the interface trap density near the band edges in 4Hsilicon carbide metal-oxide-semiconductor capacitors  

E-Print Network [OSTI]

­silicon carbide metal-oxide-semiconductor capacitors Gilyong Chung, Chin Che Tin, and John R. Williamsa) Physics. Silicon carbide is the only wide band gap semiconductor that has a native oxide, and metal temperature capacitance­voltage measurements are reported for SiO2/4H­SiC n and p type metal

Pantelides, Sokrates T.

130

Banded electromagnetic stator core  

DOE Patents [OSTI]

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figs.

Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

1996-06-11T23:59:59.000Z

131

Banded electromagnetic stator core  

DOE Patents [OSTI]

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.

Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

1994-04-05T23:59:59.000Z

132

Utility-Scale Solar Power Converter: Agile Direct Grid Connect Medium Voltage 4.7-13.8 kV Power Converter for PV Applications Utilizing Wide Band Gap Devices  

SciTech Connect (OSTI)

Solar ADEPT Project: Satcon is developing a compact, lightweight power conversion device that is capable of taking utility-scale solar power and outputting it directly into the electric utility grid at distribution voltage levels—eliminating the need for large transformers. Transformers “step up” the voltage of the power that is generated by a solar power system so it can be efficiently transported through transmission lines and eventually “stepped down” to usable voltages before it enters homes and businesses. Power companies step up the voltage because less electricity is lost along transmission lines when the voltage is high and current is low. Satcon’s new power conversion devices will eliminate these heavy transformers and connect a utility-scale solar power system directly to the grid. Satcon’s modular devices are designed to ensure reliability—if one device fails it can be bypassed and the system can continue to run.

None

2012-01-25T23:59:59.000Z

133

Interaction of wide-band-gap single crystals with 248-nm excimer laser irradiation. X. Laser-induced near-surface absorption in single-crystal NaCl  

E-Print Network [OSTI]

are expected to play an important role in optical break- down and surface damage. II. EXPERIMENT The results of a few thousand kelvin even in the absence of visible surface damage. The origin of the laser absorption radiation. As much as 20% of the incident radiation at 248 nm must be absorbed in the near-surface region

Dickinson, J. Thomas

134

To Bridge LEDs' Green Gap, Scientists Think Small  

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

To Bridge LEDs' Green Gap, Scientists Think Small To Bridge LEDs' Green Gap, Scientists Think Small Nanostructures Half a DNA Strand-Wide Show Promise for Efficient LEDs April 4,...

135

First principles investigation of scaling trends of zirconium silicate interface band offsets  

E-Print Network [OSTI]

First principles investigation of scaling trends of zirconium silicate interface band offsets out to investigate the scaling trends of band offsets at model silicon/zirconium silicate interfaces. Owing to the d character of zirconium silicate conduction bands, the band gap and band offset are shown

Dutton, Robert W.

136

Windy Gap Firming Project  

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

Infrastructure projects Interconnection OASIS OATT Windy Gap Firming Project, Final Environmental Impact Statement, DOEEIS-0370 (cooperating agency) Western's proposed...

137

RESOLVING THE GAP AND AU-SCALE ASYMMETRIES IN THE PRE-TRANSITIONAL DISK OF V1247 ORIONIS  

SciTech Connect (OSTI)

Pre-transitional disks are protoplanetary disks with a gapped disk structure, potentially indicating the presence of young planets in these systems. In order to explore the structure of these objects and their gap-opening mechanism, we observed the pre-transitional disk V1247 Orionis using the Very Large Telescope Interferometer, the Keck Interferometer, Keck-II, Gemini South, and IRTF. This allows us to spatially resolve the AU-scale disk structure from near- to mid-infrared wavelengths (1.5-13 {mu}m), tracing material at different temperatures and over a wide range of stellocentric radii. Our observations reveal a narrow, optically thick inner-disk component (located at 0.18 AU from the star) that is separated from the optically thick outer disk (radii {approx}> 46 AU), providing unambiguous evidence for the existence of a gap in this pre-transitional disk. Surprisingly, we find that the gap region is filled with significant amounts of optically thin material with a carbon-dominated dust mineralogy. The presence of this optically thin gap material cannot be deduced solely from the spectral energy distribution, yet it is the dominant contributor at mid-infrared wavelengths. Furthermore, using Keck/NIRC2 aperture masking observations in the H, K', and L' bands, we detect asymmetries in the brightness distribution on scales of {approx}15-40 AU, i.e., within the gap region. The detected asymmetries are highly significant, yet their amplitude and direction changes with wavelength, which is not consistent with a companion interpretation but indicates an inhomogeneous distribution of the gap material. We interpret this as strong evidence for the presence of complex density structures, possibly reflecting the dynamical interaction of the disk material with sub-stellar mass bodies that are responsible for the gap clearing.

Kraus, Stefan; Espaillat, Catherine; Wilner, David J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-78, Cambridge, MA 02138 (United States); Ireland, Michael J. [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Sitko, Michael L.; Swearingen, Jeremy R.; Werren, Chelsea [Department of Physics, University of Cincinnati, Cincinnati, OH 45221 (United States); Monnier, John D.; Calvet, Nuria [Department of Astronomy, University of Michigan, 918 Dennison Building, Ann Arbor, MI 48109 (United States); Grady, Carol A. [Eureka Scientific Inc., Oakland, CA 94602 (United States); Harries, Tim J. [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Hoenig, Sebastian F. [Department of Physics, University of California Santa Barbara, Broida Hall, Santa Barbara, CA 93106 (United States); Russell, Ray W. [The Aerospace Corporation, Los Angeles, CA 90009 (United States)

2013-05-01T23:59:59.000Z

138

College Gender Gaps  

E-Print Network [OSTI]

College Gender Gaps BY MARY ANN BRONSONBY MARY ANN BRONSON FALL 2013 W HY DO WOMEN ATTEND collegerelationship is crucial. Mary Ann Bronson, a Ph.D. candidate

Bronson, Mary Ann

2013-01-01T23:59:59.000Z

139

Correlation between surface chemistry, density and band gap in...  

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

of WO3 films. The XPS analyses indicate the formation of stoichiometric WO3 with tungsten existing in fully oxidized valence state (W6+). However, WO3 films grown at high...

140

Band Gap Optimization of Two-Dimensional Photonic Crystals Using ...  

E-Print Network [OSTI]

Jul 10, 2009 ... proven very important as device components for integrated optics ...... Inhibited spontaneous emission in solid-state physics and electronics.

2009-07-10T23:59:59.000Z

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


141

Experimental study of photonic band gap accelerator structures  

E-Print Network [OSTI]

This thesis reports theoretical and experimental research on a novel accelerator concept using a photonic bandgap (PBG) structure. Major advances in higher order mode (HOM) damping are required for the next generation of ...

Marsh, Roark A

2009-01-01T23:59:59.000Z

142

Characterization of Novel Semiconductor Alloys for Band Gap Engineering  

E-Print Network [OSTI]

including high efficiency photovoltaics and light emittingEngineering 1.2.1 High Efficiency Photovoltaics 1.2.2 High1.2.1 High Efficiency Photovoltaics There has been

Broesler, Robert Joseph

2010-01-01T23:59:59.000Z

143

Method for Creating Photonic Band Gap Materials - Energy Innovation Portal  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces andMapping theEnergy StorageAdvancedMetamaterialsInnovationEnergy

144

Correlation between surface chemistry, density and band gap in  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed Newcatalyst phases on &gamma;-Al2O3. | EMSLHydrogenin

145

Substrate-Induced Band-Gap Opening in Epitaxial Graphene  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystalline Gallium Oxide ThinIon CoolingSubstrate

146

Substrate-Induced Band-Gap Opening in Epitaxial Graphene  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystalline Gallium Oxide ThinIon CoolingSubstrateSubstrate-Induced

147

Substrate-Induced Band-Gap Opening in Epitaxial Graphene  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystalline Gallium Oxide ThinIon

148

Substrate-Induced Band-Gap Opening in Epitaxial Graphene  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassiveSubmittedStatus TomAbout »Lab (Newport NewsStyle Substrate-Induced

149

Study of transmission line attenuation in broad band millimeter wave frequency range  

SciTech Connect (OSTI)

Broad band millimeter wave transmission lines are used in fusion plasma diagnostics such as electron cyclotron emission (ECE), electron cyclotron absorption, reflectometry and interferometry systems. In particular, the ECE diagnostic for ITER will require efficient transmission over an ultra wide band, 100 to 1000 GHz. A circular corrugated waveguide transmission line is a prospective candidate to transmit such wide band with low attenuation. To evaluate this system, experiments of transmission line attenuation were performed and compared with theoretical loss calculations. A millimeter wave Michelson interferometer and a liquid nitrogen black body source are used to perform all the experiments. Atmospheric water vapor lines and continuum absorption within this band are reported. Ohmic attenuation in corrugated waveguide is very low; however, there is Bragg scattering and higher order mode conversion that can cause significant attenuation in this transmission line. The attenuation due to miter bends, gaps, joints, and curvature are estimated. The measured attenuation of 15 m length with seven miter bends and eighteen joints is 1 dB at low frequency (300 GHz) and 10 dB at high frequency (900 GHz), respectively.

Pandya, Hitesh Kumar B. [ITER-India, IPR, Gandhinagar, Gujarat (India)] [ITER-India, IPR, Gandhinagar, Gujarat (India); Austin, M. E. [Institute for Fusion Studies, the University of Texas at Austin, Austin, Texas (United States)] [Institute for Fusion Studies, the University of Texas at Austin, Austin, Texas (United States); Ellis, R. F. [Laboratory for Plasma and Fusion Energy Studies, University of Maryland, College Park, Maryland 20742 (United States)] [Laboratory for Plasma and Fusion Energy Studies, University of Maryland, College Park, Maryland 20742 (United States)

2013-10-15T23:59:59.000Z

150

Generation gaps in engineering?  

E-Print Network [OSTI]

There is much enthusiastic debate on the topic of generation gaps in the workplace today; what the generational differences are, how to address the apparent challenges, and if the generations themselves are even real. ...

Kim, David J. (David Jinwoo)

2008-01-01T23:59:59.000Z

151

Fiber optic gap gauge  

SciTech Connect (OSTI)

A lightweight, small size, high sensitivity gauge for indirectly measuring displacement or absolute gap width by measuring axial strain in an orthogonal direction to the displacement/gap width. The gap gauge includes a preferably titanium base having a central tension bar with springs connecting opposite ends of the tension bar to a pair of end connector bars, and an elongated bow spring connected to the end connector bars with a middle section bowed away from the base to define a gap. The bow spring is capable of producing an axial strain in the base proportional to a displacement of the middle section in a direction orthogonal to the base. And a strain sensor, such as a Fabry-Perot interferometer strain sensor, is connected to measure the axial strain in the base, so that the displacement of the middle section may be indirectly determined from the measurement of the axial strain in the base.

Wood, Billy E. (Livermore, CA); Groves, Scott E. (Brentwood, CA); Larsen, Greg J. (Brentwood, CA); Sanchez, Roberto J. (Pleasanton, CA)

2006-11-14T23:59:59.000Z

152

Inception report and Gap analysis  

E-Print Network [OSTI]

Inception report and Gap analysis Boiler inspection Riga, June 2004 #12;Inception report and gap analysis ­ boiler inspection Table of Content 1 INTRODUCTION ................................................................................................................................. 3 2 BOILER INSTALLATIONS ­ GAP ANALYSIS

153

Broad-band beam buncher  

DOE Patents [OSTI]

A broad-band beam buncher is disclosed, comprising an evacuated housing, an electron gun therein for producing an electron beam, a buncher cavity having entrance and exit openings through which the beam is directed, grids across such openings, a source providing a positive DC voltage between the cavity and the electron gun, a drift tube through which the electron beam travels in passing through such cavity, grids across the ends of such drift tube, gaps being provided between the drift tube grids and the entrance and exit grids, a modulator for supplying an ultrahigh frequency modulating signal to the drift tube for producing velocity modulation of the electrons in the beam, a drift space in the housing through which the velocity modulated electron beam travels and in which the beam is bunched, and a discharge opening from such drift tube and having a grid across such opening through which the bunched electron beam is discharged into an accelerator or the like. The buncher cavity and the drift tube may be arranged to constitute an extension of a coaxial transmission line which is employed to deliver the modulating signal from a signal source. The extended transmission line may be terminated in its characteristic impedance to afford a broad-band response and the device as a whole designed to effect broad-band beam coupling, so as to minimize variations of the output across the response band.

Goldberg, David A. (Walnut Creek, CA); Flood, William S. (Berkeley, CA); Arthur, Allan A. (Martinez, CA); Voelker, Ferdinand (Orinda, CA)

1986-01-01T23:59:59.000Z

154

Amplitude modulation free, wide band frequency modulated oscillator  

E-Print Network [OSTI]

oscillator- - - - - ? ? - ? 3 15 ~ Iiide Bmd Frc saency Lodulator Relatively Free of A@elf tude Modulation-? ? 35 1~'i. Tank Uoltare Versus Fx~tuency or . 'evcral Loads ? - ? ? - 35 17. Screon Voltage Versus Frequency? 10. Amclitude Lodulafion Envelope... of Conventional Design- - ? 39 19 ' ~litude Ltodulation Eave" ope of !iem Design- - - ? - - ? 39 20. Tank Voltage Versus 11~-, coney of Conventisnal Design Hew Design INTRODUCTION The accurate and rapid determination and location of faults is very important...

Nelson, Dick Frank

1951-01-01T23:59:59.000Z

155

Uncertainties in Gapped Graphene  

E-Print Network [OSTI]

Motivated by graphene-based quantum computer we examine the time-dependence of the position-momentum and position-velocity uncertainties in the monolayer gapped graphene. The effect of the energy gap to the uncertainties is shown to appear via the Compton-like wavelength $\\lambda_c$. The uncertainties in the graphene are mainly contributed by two phenomena, spreading and zitterbewegung. While the former determines the uncertainties in the long-range of time, the latter gives the highly oscillation to the uncertainties in the short-range of time. The uncertainties in the graphene are compared with the corresponding values for the usual free Hamiltonian $\\hat{H}_{free} = (p_1^2 + p_2^2) / 2 M$. It is shown that the uncertainties can be under control within the quantum mechanical law if one can choose the gap parameter $\\lambda_c$ freely.

Eylee Jung; Kwang S. Kim; DaeKil Park

2012-03-20T23:59:59.000Z

156

Mind The Gap  

E-Print Network [OSTI]

We discuss an optimisation criterion for the exact renormalisation group based on the inverse effective propagator, which displays a gap. We show that a simple extremisation of the gap stabilises the flow, leading to better convergence of approximate solutions towards the physical theory. This improves the reliability of truncations, most relevant for any high precision computation. These ideas are closely linked to the removal of a spurious scheme dependence and a minimum sensitivity condition. The issue of predictive power and a link to the Polchinski RG are discussed as well. We illustrate our findings by computing critical exponents for the Ising universality class.

Daniel F. Litim

2001-04-25T23:59:59.000Z

157

GAP TESTS; COMPARISON BETWEEN UN GAP TEST AND CARD GAP TEST  

E-Print Network [OSTI]

98-36 GAP TESTS; COMPARISON BETWEEN UN GAP TEST AND CARD GAP TEST by R. BRANKA and C. MICHOT, FRANCE (tel.: 33 3 44 55 65 19, fax: 33 3 44 55 65 10) ABSTRACT: UN gap test, type 1(a) or 2(a), is the recommended test in the acceptance procedure for transport of explosives in class 1. Up to the revision

Paris-Sud XI, Université de

158

Multiple gap photovoltaic device  

DOE Patents [OSTI]

A multiple gap photovoltaic device having a transparent electrical contact adjacent a first cell which in turn is adjacent a second cell on an opaque electrical contact, includes utilizing an amorphous semiconductor as the first cell and a crystalline semiconductor as the second cell.

Dalal, Vikram L. (Newark, DE)

1981-01-01T23:59:59.000Z

159

Narrow gap electronegative capacitive discharges  

SciTech Connect (OSTI)

Narrow gap electronegative (EN) capacitive discharges are widely used in industry and have unique features not found in conventional discharges. In this paper, plasma parameters are determined over a range of decreasing gap length L from values for which an electropositive (EP) edge exists (2-region case) to smaller L-values for which the EN region connects directly to the sheath (1-region case). Parametric studies are performed at applied voltage V{sub rf}=500 V for pressures of 10, 25, 50, and 100 mTorr, and additionally at 50 mTorr for 1000 and 2000 V. Numerical results are given for a parallel plate oxygen discharge using a planar 1D3v (1 spatial dimension, 3 velocity components) particle-in-cell (PIC) code. New interesting phenomena are found for the case in which an EP edge does not exist. This 1-region case has not previously been investigated in detail, either numerically or analytically. In particular, attachment in the sheaths is important, and the central electron density n{sub e0} is depressed below the density n{sub esh} at the sheath edge. The sheath oscillations also extend into the EN core, creating an edge region lying within the sheath and not characterized by the standard diffusion in an EN plasma. An analytical model is developed using minimal inputs from the PIC results, and compared to the PIC results for a base case at V{sub rf}=500 V and 50 mTorr, showing good agreement. Selected comparisons are made at the other voltages and pressures. A self-consistent model is also developed and compared to the PIC results, giving reasonable agreement.

Kawamura, E.; Lieberman, M. A.; Lichtenberg, A. J. [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)] [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)

2013-10-15T23:59:59.000Z

160

Optical gain from the direct gap transition of Ge-on-Si at room temperature  

E-Print Network [OSTI]

We report direct band gap optical gain of tensile strained n+ epitaxial Ge-on-Si at room temperature, which confirms that band-engineered Ge-on-Si is a promising gain medium for monolithic optical amplifiers and lasers on Si.

Liu, Jifeng

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


161

Mind the gap  

E-Print Network [OSTI]

In this summary of the application of Dyson-Schwinger equations to the theory and phenomenology of hadrons, some deductions following from a nonperturbative, symmetry-preserving truncation are highlighted, notable amongst which are results for pseudoscalar mesons. We also describe inferences from the gap equation relating to the radius of convergence of a chiral expansion, applications to heavy-light and heavy-heavy mesons, and quantitative estimates of the contribution of quark orbital angular momentum in pseudoscalar mesons; and recapitulate upon studies of nucleon electromagnetic form factors.

M. S. Bhagwat; A. Krassnigg; P. Maris; C. D. Roberts

2006-12-06T23:59:59.000Z

162

Wide-range voltage modulation  

SciTech Connect (OSTI)

The Superconducting Super Collider`s Medium Energy Booster Abort (MEBA) kicker modulator will supply a current pulse to the abort magnets which deflect the proton beam from the MEB ring into a designated beam stop. The abort kicker will be used extensively during testing of the Low Energy Booster (LEB) and the MEB rings. When the Collider is in full operation, the MEBA kicker modulator will abort the MEB beam in the event of a malfunction during the filling process. The modulator must generate a 14-{mu}s wide pulse with a rise time of less than 1 {mu}s, including the delay and jitter times. It must also be able to deliver a current pulse to the magnet proportional to the beam energy at any time during ramp-up of the accelerator. Tracking the beam energy, which increases from 12 GeV at injection to 200 GeV at extraction, requires the modulator to operate over a wide range of voltages (4 kV to 80 kV). A vacuum spark gap and a thyratron have been chosen for test and evaluation as candidate switches for the abort modulator. Modulator design, switching time delay, jitter and pre-fire data are presented.

Rust, K.R.; Wilson, J.M.

1992-06-01T23:59:59.000Z

163

Gap and stripline combined monitor  

DOE Patents [OSTI]

A combined gap and stripline monitor device (10) for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchotron radiation facility. The monitor has first and second beam pipe portions (11a, 11b) with an axial gap (12) therebetween. An outer pipe (14) cooperates with the first beam pipe portion (11a) to form a gap enclosure, while inner strips (23a-d) cooperate with the first beam pipe portion (11a) to form a stripline monitor, with the stripline length being the same as the gap enclosure length.

Yin, Yan (Palo Alto, CA)

1986-01-01T23:59:59.000Z

164

Gap and stripline combined monitor  

DOE Patents [OSTI]

A combined gap and stripline monitor device for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchrotron radiation facility is disclosed. The monitor has first and second beam pipe portions with an axial gap therebetween. An outer pipe cooperates with the first beam pipe portion to form a gap enclosure, while inner strips cooperate with the first beam pipe portion to form a stripline monitor, with the stripline length being the same as the gap enclosure length. 4 figs.

Yin, Y.

1986-08-19T23:59:59.000Z

165

The Pennsylvania State University Marching Blue Band Blue Band Office  

E-Print Network [OSTI]

The Pennsylvania State University Marching Blue Band Press Kit Blue Band Office 101 Blue Band Director vcc2@psu.edu orb1@psu.edu gad157@psu.edu (814) 865 - 3982 #12;History of the Blue Band The Marching Blue Band numbers 310 members which includes: 260 instrumentalists, 34 silks, 14 Touch of Blue

Maroncelli, Mark

166

Conservation notes BIRD BANDING  

E-Print Network [OSTI]

--,?1 (' Conservation notes BIRD BANDING The Hows and Whys Three Pintail ducks from North America Stewart L,. Udall, Sectetaty FISH AND WILDLIFE SERVICE #12;#12;'"'^^ ''^ "^ CONSERVATION NOTES BIRD

167

Triaxial strongly deformed bands in {sup 164}Hf and the effect of elevated yrast line  

SciTech Connect (OSTI)

Two exotic rotational bands have been identified in {sup 164}Hf and linked to known states. They are interpreted as being associated with the calculated triaxial strongly deformed (TSD) potential energy minimum. The bands are substantially stronger and are located at much lower spins than the previously discovered TSD bands in {sup 168}Hf. In addition to the proton and neutron shell gaps at large trixiality, it was proposed that the relative excitation energy of TSD bands above the yrast line plays an important role in the population of TSD bands.

Ma Wenchao [Department of Physics, Mississippi State University, Mississippi State, MS 39762 (United States)

2012-10-20T23:59:59.000Z

168

Partially filled intermediate band of Cr-doped GaN films  

SciTech Connect (OSTI)

We investigated the band structure of sputtered Cr-doped GaN (GaCrN) films using optical absorption, photoelectron yield spectroscopy, and charge transport measurements. It was found that an additional energy band is formed in the intrinsic band gap of GaN upon Cr doping, and that charge carriers in the material move in the inserted band. Prototype solar cells showed enhanced short circuit current and open circuit voltage in the n-GaN/GaCrN/p-GaN structure compared to the GaCrN/p-GaN structure, which validates the proposed concept of an intermediate-band solar cell.

Sonoda, S. [Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585 (Japan)

2012-05-14T23:59:59.000Z

169

Wide Blue Sky  

E-Print Network [OSTI]

dressed neatly in a dark blue dress, its high neck trimmedIt was covered in a light blue fabric embellished with softOF CALIFORNIA RIVERSIDE Wide Blue Sky A Thesis submitted in

Collins, Caroline Imani

2011-01-01T23:59:59.000Z

170

Band anticrossing effects in highly mismatched semiconductor alloys  

SciTech Connect (OSTI)

The first five chapters of this thesis focus on studies of band anticrossing (BAC) effects in highly electronegativity- mismatched semiconductor alloys. The concept of bandgap bowing has been used to describe the deviation of the alloy bandgap from a linear interpolation. Bowing parameters as large as 2.5 eV (for ZnSTe) and close to zero (for AlGaAs and ZnSSe) have been observed experimentally. Recent advances in thin film deposition techniques have allowed the growth of semiconductor alloys composed of significantly different constituents with ever- improving crystalline quality (e.g., GaAs{sub 1-x}N{sub x} and GaP{sub 1-x}N{sub x} with x {approx}< 0.05). These alloys exhibit many novel and interesting properties including, in particular, a giant bandgap bowing (bowing parameters > 14 eV). A band anticrossing model has been developed to explain these properties. The model shows that the predominant bowing mechanism in these systems is driven by the anticrossing interaction between the localized level associated with the minority component and the band states of the host. In this thesis I discuss my studies of the BAC effects in these highly mismatched semiconductors. It will be shown that the results of the physically intuitive BAC model can be derived from the Hamiltonian of the many-impurity Anderson model. The band restructuring caused by the BAC interaction is responsible for a series of experimental observations such as a large bandgap reduction, an enhancement of the electron effective mass, and a decrease in the pressure coefficient of the fundamental gap energy. Results of further experimental investigations of the optical properties of quantum wells based on these materials will be also presented. It will be shown that the BAC interaction occurs not only between localized states and conduction band states at the Brillouin zone center, but also exists over all of k-space. Finally, taking ZnSTe and ZnSeTe as examples, I show that BAC also occurs between localized states and the valence band states. Soft x-ray fluorescence experiments provide direct evidence of the BAC interaction in these systems. In the final chapter of the thesis, I describe and summarize my studies of optical properties of wurtzite InN and related alloys. Early studies performed on InN films grown by sputtering techniques suggested a direct bandgap of {approx}1.9 eV for this semiconductor. Very recently, high-quality InN films with much higher mobility have become available by using the molecular beam epitaxy growth method. Optical experiments carried out on these samples reveal a narrow bandgap for InN of 0.77 eV, much lower than the previously accepted value. Optical properties of InGaN and InAlN ternaries on the In rich side have also been characterized and are found to be consistent with the narrow bandgap of InN. The bandgap bowing parameters in these alloys were determined. In the context of these findings, the bandgap energies of InGaN and InAlN were found to cover a wide spectral range from the infrared for InN to the ultraviolet for GaN and deep ultraviolet for AlN. The significance of this work is rooted in many important applications of nitride semiconductors in optoelectronics and solar energy conversion devices.

Wu, Junqiao

2002-09-09T23:59:59.000Z

171

Influence of gap spacing on the characteristics of Trichel pulse generated in point-to-plane discharge gaps  

SciTech Connect (OSTI)

In this paper, the specific characteristics of the Trichel pulse generated in wide point-to-plane discharge gaps are investigated and compared with those of the currents generated in narrow gaps. A set of empirical formulas are derived to describe the specific characteristics. The influence of the gap spacing both on the current characteristics and on the coefficients of the formulas is studied. Based on the experiment results, an improvement is made to the space charge calculation method proposed by Lama and Gallo [J. Appl. Phys. 45, 103–113 (1974)] and the calculation results are compared to the ones obtained with Lama and Gallo's original method. With the influence of the space charge considered, the modified method obtains more accurate results of the space charge accumulating in the gap and gives a more precise description of the motion of the space charge in the gap. Based on the calculation results, the influence of the space charge on the distribution of the electric field is examined and the influence of the gap spacing on the current characteristics is also studied.

Li, Zhen, E-mail: leezhen1988@gmail.com; Zhang, Bo, E-mail: shizbcn@mail.tsinghua.edu.cn; He, Jinliang, E-mail: hejl@tsinghua.edu.cn; Xu, Yongsheng, E-mail: evebus@163.com [State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084 (China)] [State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084 (China)

2014-01-15T23:59:59.000Z

172

Virtual gap dielectric wall accelerator  

DOE Patents [OSTI]

A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A

2013-11-05T23:59:59.000Z

173

Majorana Flat Bands in s-Wave Gapless Topological Superconductors  

E-Print Network [OSTI]

We demonstrate how the non-trivial interplay between spin-orbit coupling and nodeless $s$-wave superconductivity can drive a fully gapped two-band topological insulator into a time-reversal invariant gapless topological superconductor supporting symmetry-protected Majorana flat bands. We characterize topological phase diagrams by a ${\\mathbb Z}_2 \\times{\\mathbb Z}_2$ partial Berry-phase invariant, and show that, despite the trivial crystal geometry, no unique bulk-boundary correspondence exists. We trace this behavior to the anisotropic quasiparticle bulk gap closing, linear vs. quadratic, and argue that this provides a unifying principle for gapless topological superconductivity. Experimental implications for tunneling conductance measurements are addressed, relevant for lead chalcogenide materials.

Shusa Deng; Gerardo Ortiz; Amrit Poudel; Lorenza Viola

2014-04-28T23:59:59.000Z

174

Highly Mismatched Alloys for Intermediate Band Solar Cells  

SciTech Connect (OSTI)

It has long been recognized that the introduction of a narrow band of states in a semiconductor band gap could be used to achieve improved power conversion efficiency in semiconductor-based solar cells. The intermediate band would serve as a ''stepping stone'' for photons of different energy to excite electrons from the valence to the conduction band. An important advantage of this design is that it requires formation of only a single p-n junction, which is a crucial simplification in comparison to multijunction solar cells. A detailed balance analysis predicts a limiting efficiency of more than 50% for an optimized, single intermediate band solar cell. This is higher than the efficiency of an optimized two junction solar cell. Using ion beam implantation and pulsed laser melting we have synthesized Zn{sub 1-y}Mn{sub y}O{sub x}Te{sub 1-x} alloys with x<0.03. These highly mismatched alloys have a unique electronic structure with a narrow oxygen-derived intermediate band. The width and the location of the band is described by the Band Anticrossing model and can be varied by controlling the oxygen content. This provides a unique opportunity to optimize the absorption of solar photons for best solar cell performance. We have carried out systematic studies of the effects of the intermediate band on the optical and electrical properties of Zn{sub 1-y}Mn{sub y}O{sub x}Te{sub 1-x} alloys. We observe an extension of the photovoltaic response towards lower photon energies, which is a clear indication of optical transitions from the valence to the intermediate band.

Walukiewicz, W.; Yu, K.M.; Wu, J.; Ager III, J.W.; Shan, W.; Scrapulla, M.A.; Dubon, O.D.; Becla, P.

2005-03-21T23:59:59.000Z

175

Multiple input electrode gap controller  

DOE Patents [OSTI]

A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows. 17 figs.

Hysinger, C.L.; Beaman, J.J.; Melgaard, D.K.; Williamson, R.L.

1999-07-27T23:59:59.000Z

176

Band crossing in a shears band of {sup 108}Cd  

SciTech Connect (OSTI)

The level lifetimes have been measured for a shears band of {sup 108}Cd that exhibits band crossing. The observed level energies and B(M1) rates have been successfully described by a semiclassical geometric model based on shear mechanism. In this geometric model, the band crossing in the shears band has been described as the reopening of the angle between the blades of a shear.

Roy, Santosh; Datta, Pradip; Pal, S.; Chattopadhyay, S.; Bhattacharya, S.; Goswami, A.; Jain, H. C.; Joshi, P. K.; Bhowmik, R. K.; Kumar, R.; Muralithar, S.; Singh, R. P.; Madhavan, N.; Rao, P. V. Madhusudhana [S. N. Bose National Centre for Basic Sciences. Block JD, Sector III, Saltlake City, Kolkata 700098 (India); iThemba Labs, Post Office Box 722, Somerset West 7129 (South Africa); Saha Institute of Nuclear Physics, 1/AF Bidhannager Kolkata, 700 064 (India); Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005 (India); Inter University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Department of Physics, Andra University, Visakhapatnam 530 003 (India)

2010-05-15T23:59:59.000Z

177

Wide Bandgap Power Electronics  

Office of Environmental Management (EM)

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178

Emplacement Gantry Gap Analysis Study  

SciTech Connect (OSTI)

To date, the project has established important to safety (ITS) performance requirements for structures, systems, and components (SSCs) based on the identification and categorization of event sequences that may result in a radiological release. These performance requirements are defined within the ''Nuclear Safety Design Bases for License Application'' (NSDB) (BSC 2005 [DIRS 171512], Table A-11). Further, SSCs credited with performing safety functions are classified as ITS. In turn, assurance that these SSCs will perform as required is sought through the use of consensus codes and standards. This gap analysis is based on the design completed for license application only. Accordingly, identification of ITS SSCs beyond those defined within the NSDB are based on designs that may be subject to further development during detail design. Furthermore, several design alternatives may still be under consideration to satisfy certain safety functions, and final selection will not be determined until further design development has occurred. Therefore, for completeness, alternative designs currently under consideration will be discussed throughout this study. This gap analysis will evaluate each code and standard identified within the ''Emplacement Gantry ITS Standards Identification Study'' (BSC 2005 [DIRS 173586]) to ensure each ITS performance requirement is fully satisfied. When a performance requirement is not fully satisfied, a gap is highlighted. This study will identify requirements to supplement or augment the code or standard to meet performance requirements. Further, this gap analysis will identify nonstandard areas of the design that will be subject to a design development plan. Nonstandard components and nonstandard design configurations are defined as areas of the design that do not follow standard industry practices or codes and standards. Whereby, assurance that an SSC will perform as required may not be readily sought though the use of consensus standards. This gap analysis is prepared by the Emplacement and Retrieval (E&R) project team and is intended for the sole use of the Engineering department in work regarding the emplacement gantry. Yucca Mountain Project personnel from the E&R project team should be consulted before use of this gap analysis for purposes other than those stated herein or by individuals other than authorized by the Engineering department.

R. Thornley

2005-05-27T23:59:59.000Z

179

Hard-gapped Holographic Superconductors  

E-Print Network [OSTI]

In this work we discuss the zero temperature limit of a "p-wave" holographic superconductor. The bulk description consists of a non-Abelian SU(2) gauge fields minimally coupled to gravity. We numerically construct the zero temperature solution which is the gravity dual of the superconducting ground state of the "p-wave" holographic superconductors. The solution is a smooth soliton with zero horizon size and shows an emergent conformal symmetry in the IR. We found the expected superconducting behavior. Using the near horizon analysis we show that the system has a "hard gap" for the relevant gauge field fluctuations. At zero temperature the real part of the conductivity is zero for an excitation frequency less than the gap frequency. This is in contrast with what has been observed in similar scalar- gravity-gauge systems (holographic superconductors). We also discuss the low but finite temperature behavior of our solution.

Pallab Basu; Jianyang He; Anindya Mukherjee; Hsien-Hang Shieh

2009-12-05T23:59:59.000Z

180

Physical properties and band structure of reactive molecular beam epitaxy grown oxygen engineered HfO{sub 2{+-}x}  

SciTech Connect (OSTI)

We have conducted a detailed thin film growth structure of oxygen engineered monoclinic HfO{sub 2{+-}x} grown by reactive molecular beam epitaxy. The oxidation conditions induce a switching between (111) and (002) texture of hafnium oxide. The band gap of oxygen deficient hafnia decreases with increasing amount of oxygen vacancies by more than 1 eV. For high oxygen vacancy concentrations, defect bands form inside the band gap that induce optical transitions and p-type conductivity. The resistivity changes by several orders of magnitude as a function of oxidation conditions. Oxygen vacancies do not give rise to ferromagnetic behavior.

Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany)

2012-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "wide band gap" from the National Library of EnergyBeta (NLEBeta).
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181

Intrinsic electron and hole bands in electron-doped cuprate superconductors  

SciTech Connect (OSTI)

We propose that the upper Hubbard band (electron-like) and the Zhang-Rice singlet band (holelike) are two essential components in describing low-energy excitations of electron-doped cuprate superconductors. We find that the gap between these two bands is significantly smaller than the charge-transfer gap measured by optics and is further reduced upon doping. This indicates that the charge fluctuation is strong and the system is in the intermediate correlation regime. A two-band model is derived. In the limit that the intraband and interband hopping integrals are equal to each other, this model is equivalent to the unconstrained t-J model with on-site Coulomb repulsions.

Xiang, T.

2010-02-24T23:59:59.000Z

182

Calibration curves for some standard Gap Tests  

SciTech Connect (OSTI)

The relative shock sensitivities of explosive compositions are commonly assessed using a family of experiments that can be described by the generic term ''Gap Test.'' Gap tests include a donor charge, a test sample, and a spacer, or gap, between two explosives charges. The donor charge, gap material, and test dimensions are held constant within each different version of the gap test. The thickness of the gap is then varied to find the value at which 50% of the test samples will detonate. The gap tests measure the ease with a high-order detonation can be established in the test explosive, or the ''detonability,'' of the explosive. Test results are best reported in terms of the gap thickness at the 50% point. It is also useful to define the shock pressure transmitted into the test sample at the detonation threshold. This requires calibrating the gap test in terms of shock pressure in the gap as a function of the gap thickness. It also requires a knowledge of the shock Hugoniot of the sample explosive. We used the 2DE reactive hydrodynamic code with Forest Fire burn rates for the donor explosives to calculate calibration curves for several gap tests. The model calculations give pressure and particle velocity on the centerline of the experimental set-up and provide information about the curvature and pulse width of the shock wave. 10 refs., 1 fig.

Bowman, A.L.; Sommer, S.C.

1989-01-01T23:59:59.000Z

183

Air Gap Tunin Yilin Mao, Yashwanth  

E-Print Network [OSTI]

Air Gap Tunin Yilin Mao, Yashwanth Electrical Engineering Departm The Unive ymao1@olemiss.edu, ypadooru@ Abstract-- An adjustable air gap was proposed the resonant frequency of patch antennas the frequency of coaxially fed p center conductor has to be de-soldered and r time the width of the air gap

Elsherbeni, Atef Z.

184

Generation Gaps in Engineering? David J. Kim  

E-Print Network [OSTI]

Generation Gaps in Engineering? by David J. Kim B.S., Computer Science and Engineering;3 Generation Gaps in Engineering? by David J. Kim Submitted to the System Design and Management Program on May in Engineering and Management ABSTRACT There is much enthusiastic debate on the topic of generation gaps

Gabrieli, John

185

Band-engineered SrTiO{sub 3} nanowires for visible light photocatalysis  

SciTech Connect (OSTI)

We have theoretically investigated the structural, electronic, and optical properties of perovskite SrTiO{sub 3} nanowires for use in visible light photocatalytic applications using pseudopotential density-functional theory calculations. The electronic structure calculations show that the band gap is modified in the SrTiO{sub 3} nanowires compared with that of the bulk. For TiO{sub 2}-terminated nanowires, the mid-band states induced by the combination of oxygen and strontium atoms on the surface lead to a shift in the valence band toward the conduction band without interference from the edge of the conduction band, which reduces the band gap. On the contrary, the electronic states induced by the combination of oxygen and strontium atoms on the surface of SrO-terminated nanowires lead to a shift in the conduction band toward the valence band. The calculated optical results indicate that the absorption edge of the nanowires shift towards the red-light region. These theoretical results suggest that perovskite SrTiO{sub 3} nanowires are promising candidates for use in visible light photocatalytic processes such as solar-assisted water splitting reactions.

Fu, Q.; He, T.; Li, J. L.; Yang, G. W. [State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong (China)

2012-11-15T23:59:59.000Z

186

FAQS Gap Analysis Qualification Card - Senior Technical Safety...  

Office of Environmental Management (EM)

Gap Analysis Qualification Card - Senior Technical Safety Manager FAQS Gap Analysis Qualification Card - Senior Technical Safety Manager Functional Area Qualification Standard Gap...

187

Searching Room Temperature Ferromagnetism in Wide Gap Semiconductors Fe-doped Strontium Titanate and Zinc Oxide  

E-Print Network [OSTI]

Scientic findings in the very beginning of the millennium are taking us a step further in the new paradigm of technology: spintronics. Upgrading charge-based electronics with the additional degree of freedom of the carriers spin-state, spintronics opens a path to the birth of a new generation of devices with the potential advantages of non-volatility and higher processing speed, integration densities and power efficiency. A decisive step towards this new age lies on the attribution of magnetic properties to semiconductors, the building block of today's electronics, that is, the realization of ferromagnetic semiconductors (FS) with critical temperatures above room temperature. Unfruitful search for intrinsic RT FS lead to the concept of Dilute(d) Magnetic Semiconductors (DMS): ordinary semiconductor materials where 3 d transition metals randomly substitute a few percent of the matrix cations and, by some long-range mechanism, order ferromagnetically. The times are of intense research activity and the last few ...

Pereira, LMC; Wahl, U

188

Inverse Design of Mn-based ternary p-type wide-gap oxides  

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

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189

Inverse Design of Mn-based ternary p-type wide-gap oxides  

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

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190

Wide-Bandgap Semiconductors  

SciTech Connect (OSTI)

With the increase in demand for more efficient, higher-power, and higher-temperature operation of power converters, design engineers face the challenge of increasing the efficiency and power density of converters [1, 2]. Development in power semiconductors is vital for achieving the design goals set by the industry. Silicon (Si) power devices have reached their theoretical limits in terms of higher-temperature and higher-power operation by virtue of the physical properties of the material. To overcome these limitations, research has focused on wide-bandgap materials such as silicon carbide (SiC), gallium nitride (GaN), and diamond because of their superior material advantages such as large bandgap, high thermal conductivity, and high critical breakdown field strength. Diamond is the ultimate material for power devices because of its greater than tenfold improvement in electrical properties compared with silicon; however, it is more suited for higher-voltage (grid level) higher-power applications based on the intrinsic properties of the material [3]. GaN and SiC power devices have similar performance improvements over Si power devices. GaN performs only slightly better than SiC. Both SiC and GaN have processing issues that need to be resolved before they can seriously challenge Si power devices; however, SiC is at a more technically advanced stage than GaN. SiC is considered to be the best transition material for future power devices before high-power diamond device technology matures. Since SiC power devices have lower losses than Si devices, SiC-based power converters are more efficient. With the high-temperature operation capability of SiC, thermal management requirements are reduced; therefore, a smaller heat sink would be sufficient. In addition, since SiC power devices can be switched at higher frequencies, smaller passive components are required in power converters. Smaller heat sinks and passive components result in higher-power-density power converters. With the advent of the use of SiC devices it is imperative that models of these be made available in commercial simulators. This enables power electronic designers to simulate their designs for various test conditions prior to fabrication. To build an accurate transistor-level model of a power electronic system such as an inverter, the first step is to characterize the semiconductor devices that are present in the system. Suitable test beds need to be built for each device to precisely test the devices and obtain relevant data that can be used for modeling. This includes careful characterization of the parasitic elements so as to emulate the test setup as closely as possible in simulations. This report is arranged as follows: Chapter 2--The testing and characterization of several diodes and power switches is presented. Chapter 3--A 55-kW hybrid inverter (Si insulated gate bipolar transistor--SiC Schottky diodes) device models and test results are presented. A detailed description of the various test setups followed by the parameter extraction, modeling, and simulation study of the inverter performance is presented. Chapter 4--A 7.5-kW all-SiC inverter (SiC junction field effect transistors (JFET)--SiC Schottky diodes) was built and tested. The models built in Saber were validated using the test data and the models were used in system applications in the Saber simulator. The simulation results and a comparison of the data from the prototype tests are discussed in this chapter. Chapter 5--The duration test results of devices utilized in buck converters undergoing reliability testing are presented.

Chinthavali, M.S.

2005-11-22T23:59:59.000Z

191

Evidence of Eu{sup 2+} 4f electrons in the valence band spectra of EuTiO{sub 3} and EuZrO{sub 3}  

SciTech Connect (OSTI)

We report on optical band gap and valence electronic structure of two Eu{sup 2+}-based perovskites, EuTiO{sub 3} and EuZrO{sub 3} as revealed by diffuse optical scattering, electron energy loss spectroscopy, and valence-band x-ray photoelectron spectroscopy. The data show good agreement with the first-principles studies in which the top of the valence band structure is formed by the narrow Eu 4f{sup 7} electron band. The O 2p band shows the features similar to those of the Ba(Sr)TiO{sub 3} perovskites except that it is shifted to higher binding energies. Appearance of the Eu{sup 2+} 4f{sup 7} band is a reason for narrowing of the optical band gap in the title compounds as compared to their Sr-based analogues.

Kolodiazhnyi, T. [National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Valant, M. [Materials Research Laboratory, University of Nova Gorica, Vipavska 13, 5000 Nova Gorica (Slovenia); Williams, J. R. [International Center for Young Scientists (ICYS), MANA, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Bugnet, M.; Botton, G. A. [Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Ohashi, N. [International Center for Materials Nanoarchitectonics, MANA, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Sakka, Y. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

2012-10-15T23:59:59.000Z

192

Goncu, JASA-EL Exploiting pattern transformation to tune phononic band  

E-Print Network [OSTI]

.05 × 103 kg/m3 , Young's modulus Er = 360 kPa, shear modulus Gr = 120 kPa and longitudinal speed of sound . The attenuation of electromagnetic, acoustic or elastic waves in certain frequency ranges known as band gaps numerically the propagation of elastic waves in a 2D bi-disperse granular crystal composed of large (and soft

Luding, Stefan

193

Numerical Calculation of Density of States and Band Structure A Thesis Submitted in Partial Satisfaction  

E-Print Network [OSTI]

combustion engines, with the majority of energy lost in terms of waste heat. In theory, the waste heat can. Therefore, all absorption of light happens near the band gap energy range. By changing the BS of a crystal result. 1. INTRODUCTION Energy consumption has become an important issue lately, with global shortage

Belanger, David P.

194

The effect of spin-orbit coupling in band structure of few-layer graphene  

SciTech Connect (OSTI)

Topological insulators are electronic materials that have a bulk band gap like an ordinary insulator but have protected conducting states on their edge or surface. This can be happened due to spin-orbit coupling and time-reversal symmetry. Moreover, the edge current flows through their edge or surface depends on its spin orientation and also it is robust against non-magnetic impurities. Therefore, topological insulators are predicted to be useful ranging from spintronics to quantum computation. Graphene was first predicted to be the precursor of topological insulator by Kane-Mele. They developed a Hamiltonian model to describe the gap opening in graphene. In this work, we investigate the band structure of few-layer graphene by using this model with analytical approach. The results of our calculations show that the gap opening occurs at K and K’ point, not only in single layer, but also in bilayer and trilayer graphene.

Sahdan, Muhammad Fauzi, E-mail: sahdan89@yahoo.co.id; Darma, Yudi, E-mail: sahdan89@yahoo.co.id [Department of Physics, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132 (Indonesia)

2014-03-24T23:59:59.000Z

195

Calibration of Indoor UWB Sub-band Divided Ray Tracing Using Multiobjective Simulated Annealing  

E-Print Network [OSTI]

, Sweden; 5 ICTEAM, Universit´e catholique de Louvain, Belgium Abstract--Sub-band divided ray tracing (RT) has been widely used to reproduce as reliably as possible the ultra-wideband (UWB) radio wave the accuracy of sub-band divided RT in terms of the power delay profile (PDP) and the root mean square (RMS

Zemen, Thomas

196

Gap between active and passive solar heating  

SciTech Connect (OSTI)

The gap between active and passive solar could hardly be wider. The reasons for this are discussed and advantages to narrowing the gap are analyzed. Ten years of experience in both active and passive systems are reviewed, including costs, frequent problems, performance prediction, performance modeling, monitoring, and cooling concerns. Trends are analyzed, both for solar space heating and for service water heating. A tendency for the active and passive technologies to be converging is observed. Several recommendations for narrowing the gap are presented.

Balcomb, J.D.

1985-01-01T23:59:59.000Z

197

Chiral gap effect in curved space  

E-Print Network [OSTI]

We discuss a new type of QCD phenomenon induced in curved space. In the QCD vacuum a mass gap of Dirac fermions is attributed to the spontaneous breaking of chiral symmetry. If the curvature is positive large, the chiral condensate melts but a chiral invariant mass gap can still remain, which we name the chiral gap effect in curved space. This leads to decoupling of quark deconfinement which implies a view of black holes surrounded by a first-order QCD phase transition.

Antonino Flachi; Kenji Fukushima

2014-06-25T23:59:59.000Z

198

Control of ionization processes in high band gap materials via tailored  

E-Print Network [OSTI]

on Ultrafast Electron Dynamics in Femtosecond Optical Breakdown of Dielectrics," Phys. Rev. Lett. 83, 5182­5182

Kassel, Universität

199

Strain-tunable Photonic Band Gap Microcavity Waveguides in Silicon at 1.55 m  

E-Print Network [OSTI]

+ , Sang-Gook Kim+ * Columbia University, New York, NY 10027 + Massachusetts Institute of Technology for reconfiguration of the optical characteristics based on user-demand, but also for compensation against external the Optical Response of Photonic Bandgap Structures, edited by Philippe M. Fauchet, Paul V. Braun, Proceedings

200

Tunable band gap in graphene with a noncentrosymmetric superlattice potential Rakesh P. Tiwari and D. Stroud  

E-Print Network [OSTI]

and a hexagonal Brillouin zone BZ . The Fermi-energy EF of homogeneous, neutral graphene lies at the so A number of workers have investigated the possibility of building graphene electronic circuits without of the low-energy charge carriers is anisotropically renormalized,11 while a corrugated graphene sheet

Stroud, David

Note: This page contains sample records for the topic "wide band gap" from the National Library of EnergyBeta (NLEBeta).
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201

E-Print Network 3.0 - accurate band gaps Sample Search Results  

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

Technological University Collection: Physics 7 Improving the efficiency of bulk heterojunction solar cells Summary: the amount of photons absorbed by the film by decreasing the...

202

Bispyridinium-phenylene-based copolymers: low band gap n-type alternating copolymers  

E-Print Network [OSTI]

Bispyridinium-phenylene-based conjugated donor–acceptor copolymers were synthesized by a Stille cross-coupling and cyclization sequence. These polyelectrolytes are freely soluble in organic solvents and display broad optical ...

Swager, Timothy Manning

203

Detection of DNA Hybridization Using the Near-Infrared Band-Gap  

E-Print Network [OSTI]

shift of 2 meV, with a detection sensitivity of 6 nM. The energy shift is modeled by correlating in the solution- based systems, is advantageous due to the sensitivity and selectivity of the technique.14 absorption of blood and tissue17-19 and the low auto- fluorescence of cells20 in the nIR. Furthermore, SWNTs

Allen, Jont

204

Photonic band gap airbridge microcavity resonances in GaAs/AlxOy waveguides  

E-Print Network [OSTI]

-dielectric-contrast GaAs/AlxOy III­V compound semiconductor structure. The photonic crystal is defined by a regularly of optical states will be modified and quantized by such a cavity. Typical semiconductor optical cavities measurements of a one- dimensional PBG air-bridge optical microcavity are pre- sented here. A schematic

Fan, Shanhui

205

Engineering the electromagnetic vacuum for controlling light with light in a photonic-band-gap microchip  

E-Print Network [OSTI]

laser beams ( 1 W steady-state holding power and 5 nW switching power) through mutual coherent resonant broadened collection of "atoms" situated adjacent to the waveguide channel. The "inverted" atomic system can the PBG, light cannot propagate, leading to some fundamentally new opti- cal phenomena

John, Sajeev

206

A New Gap-Opening Mechanism in a Triple-Band Metal  

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

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207

A New Gap-Opening Mechanism in a Triple-Band Metal  

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

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208

A New Gap-Opening Mechanism in a Triple-Band Metal  

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

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209

A New Gap-Opening Mechanism in a Triple-Band Metal  

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

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210

A New Gap-Opening Mechanism in a Triple-Band Metal  

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

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211

Second harmonic generation from direct band gap quantum dots pumped by femtosecond laser pulses  

SciTech Connect (OSTI)

We report on nonlinear optical experiments performed on Cu{sub 2}S quantum dots (QDs) pumped by femtosecond laser pulses. We conduct a theoretical simulation and experiments to determine their second harmonic generation characteristics. Furthermore, we demonstrate that the QDs have a second harmonic generation conversion efficiency of up to 76%. Our studies suggest that these Cu{sub 2}S QDs can be used for solar cells, bioimaging, biosensing, and electric detection.

Liu, Liwei, E-mail: liulw@cust.edu.cn; Wang, Yue; Hu, Siyi; Ren, Yu; Huang, Chen [School of Science, Changchun University of Science and Technology, Changchun, Jilin 130022, People's Republic of China and International Joint Research Center for Nanophotonics and Biophotonics, Changchun University of Science and Technology, Changchun, Jilin 130022 (China)

2014-02-21T23:59:59.000Z

212

Tuning laser-induced band gaps in graphene Hernn L. Calvo,1,2  

E-Print Network [OSTI]

Statistischen Physik, RWTH Aachen University, D-52056 Aachen, Germany 3 CIN2 (ICN­CSIC), Catalan Institute-infrared laser technology in a transport setup, thereby opening prom- ising prospects for graphene to the Dirac points K and K . Since we consider a clean sample and given that the ac field does not introduce

213

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

E-Print Network [OSTI]

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

John, Sajeev

214

Tunable micro-cavities in photonic band-gap yarns and optical fibers  

E-Print Network [OSTI]

The vision behind this work is the fabrication of high performance innovative fiber-based optical components over kilometer length-scales. The optical properties of these fibers derive from their multilayer dielectric ...

Benoit, Gilles, Ph. D. Massachusetts Institute of Technology

2006-01-01T23:59:59.000Z

215

Excitation, Ionization, and Desorption: How Sub-band gap Photons Modify the  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing ZirconiaPolicy and Assistance100 tonusingdeposition. | EMSLStructure of

216

A New Gap-Opening Mechanism in a Triple-Band Metal  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011A First Look

217

Band-Gap Engineering of Carbon Nanotubes with Grain Boundaries. | EMSL  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone6 M. Babzien, I. Ben-Zvi, P. Study ofJ U LYOffsets at

218

Band-Gap Reduction and Dopant Interaction in Epitaxial La,Cr Co-doped  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone6 M. Babzien, I. Ben-Zvi, P. Study ofJ U LYOffsets atSrTiO3 Thin

219

Undecidability of the Spectral Gap (short version)  

E-Print Network [OSTI]

The spectral gap -- the difference in energy between the ground state and the first excited state -- is one of the most important properties of a quantum many-body system. Quantum phase transitions occur when the spectral gap vanishes and the system becomes critical. Much of physics is concerned with understanding the phase diagrams of quantum systems, and some of the most challenging and long-standing open problems in theoretical physics concern the spectral gap, such as the Haldane conjecture that the Heisenberg chain is gapped for integer spin, proving existence of a gapped topological spin liquid phase, or the Yang-Mills gap conjecture (one of the Millennium Prize problems). These problems are all particular cases of the general spectral gap problem: Given a quantum many-body Hamiltonian, is the system it describes gapped or gapless? Here we show that this problem is undecidable, in the same sense as the Halting Problem was proven to be undecidable by Turing. A consequence of this is that the spectral gap...

Cubitt, Toby; Wolf, Michael M

2015-01-01T23:59:59.000Z

220

Undecidability of the Spectral Gap (short version)  

E-Print Network [OSTI]

The spectral gap -- the difference in energy between the ground state and the first excited state -- is one of the most important properties of a quantum many-body system. Quantum phase transitions occur when the spectral gap vanishes and the system becomes critical. Much of physics is concerned with understanding the phase diagrams of quantum systems, and some of the most challenging and long-standing open problems in theoretical physics concern the spectral gap, such as the Haldane conjecture that the Heisenberg chain is gapped for integer spin, proving existence of a gapped topological spin liquid phase, or the Yang-Mills gap conjecture (one of the Millennium Prize problems). These problems are all particular cases of the general spectral gap problem: Given a quantum many-body Hamiltonian, is the system it describes gapped or gapless? Here we show that this problem is undecidable, in the same sense as the Halting Problem was proven to be undecidable by Turing. A consequence of this is that the spectral gap of certain quantum many-body Hamiltonians is not determined by the axioms of mathematics, much as Goedels incompleteness theorem implies that certain theorems are mathematically unprovable. We extend these results to prove undecidability of other low temperature properties, such as correlation functions. The proof hinges on simple quantum many-body models that exhibit highly unusual physics in the thermodynamic limit.

Toby Cubitt; David Perez-Garcia; Michael M. Wolf

2015-02-13T23:59:59.000Z

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


221

FAQS Gap Analysis Qualification Card – Criticality Safety  

Broader source: Energy.gov [DOE]

Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

222

FAQS Gap Analysis Qualification Card – Radiation Protection  

Broader source: Energy.gov [DOE]

Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

223

FAQS Gap Analysis Qualification Card – Environmental Restoration  

Broader source: Energy.gov [DOE]

Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

224

FAQS Gap Analysis Qualification Card – Construction Management  

Broader source: Energy.gov [DOE]

Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

225

FAQS Gap Analysis Qualification Card – Mechanical Systems  

Broader source: Energy.gov [DOE]

Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

226

Dilute Group III-V nitride intermediate band solar cells with contact blocking layers  

DOE Patents [OSTI]

An intermediate band solar cell (IBSC) is provided including a p-n junction based on dilute III-V nitride materials and a pair of contact blocking layers positioned on opposite surfaces of the p-n junction for electrically isolating the intermediate band of the p-n junction by blocking the charge transport in the intermediate band without affecting the electron and hole collection efficiency of the p-n junction, thereby increasing open circuit voltage (V.sub.OC) of the IBSC and increasing the photocurrent by utilizing the intermediate band to absorb photons with energy below the band gap of the absorber layers of the IBSC. Hence, the overall power conversion efficiency of a IBSC will be much higher than an conventional single junction solar cell. The p-n junction absorber layers of the IBSC may further have compositionally graded nitrogen concentrations to provide an electric field for more efficient charge collection.

Walukiewicz, Wladyslaw (Kensington, CA); Yu, Kin Man (Lafayette, CA)

2012-07-31T23:59:59.000Z

227

Strain-engineered band parameters of graphene-like SiC monolayer  

SciTech Connect (OSTI)

Using full-potential density functional theory (DFT) calculations we show that the band gap and effective masses of charge carriers in SiC monolayer (ML-SiC) in graphene-like two-dimensional honeycomb structure are tunable by strain engineering. ML-SiC was found to preserve its flat 2D graphene-like structure under compressive strain up to 7%. A transition from indirect-to-direct gap-phase is predicted to occur for a strain value lying within the interval (1.11 %, 1.76%). In both gap-phases band gap decreases with increasing strain, although the rate of decrease is different in the two gap-phases. Effective mass of electrons show a non-linearly decreasing trend with increasing tensile strain in the direct gap-phase. The strain-sensitive properties of ML-SiC, may find applications in future strain-sensors, nanoelectromechanical systems (NEMS) and nano-optomechanical systems (NOMS) and other nano-devices.

Behera, Harihar, E-mail: harihar@theglocaluniversity.in [School of Technology, The Glocal University, Mirzapur Pole, Dist.-Saharanpur, U.P.-247001, India and Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai-400076 (India); Mukhopadhyay, Gautam, E-mail: gmukh@phy.iitb.ac.in [Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai-400076 (India)

2014-10-06T23:59:59.000Z

228

Predicted band structures of III-V semiconductors in the wurtzite phase  

SciTech Connect (OSTI)

While non-nitride III-V semiconductors typically have a zinc-blende structure, they may also form wurtzite crystals under pressure or when grown as nanowhiskers. This makes electronic structure calculation difficult since the band structures of wurtzite III-V semiconductors are poorly characterized. We have calculated the electronic band structure for nine III-V semiconductors in the wurtzite phase using transferable empirical pseudopotentials including spin-orbit coupling. We find that all the materials have direct gaps. Our results differ significantly from earlier ab initio calculations, and where experimental results are available (InP, InAs, and GaAs) our calculated band gaps are in good agreement. We tabulate energies, effective masses, and linear and cubic Dresselhaus zero-field spin-splitting coefficients for the zone-center states. The large zero-field spin-splitting coefficients we find may facilitate the development of spin-based devices.

De, A.; Pryor, Craig E. [Department of Physics and Astronomy and Optical Science and Technology Center, University of Iowa, Iowa City, Iowa 52242 (United States)

2010-04-15T23:59:59.000Z

229

Gap Assessment (FY 13 Update)  

SciTech Connect (OSTI)

To help guide its future data collection efforts, The DOE GTO funded a data gap analysis in FY2012 to identify high potential hydrothermal areas where critical data are needed. This analysis was updated in FY2013 and the resulting datasets are represented by this metadata. The original process was published in FY 2012 and is available here: https://pangea.stanford.edu/ERE/db/GeoConf/papers/SGW/2013/Esposito.pdf Though there are many types of data that can be used for hydrothermal exploration, five types of exploration data were targeted for this analysis. These data types were selected for their regional reconnaissance potential, and include many of the primary exploration techniques currently used by the geothermal industry. The data types include: 1. well data 2. geologic maps 3. fault maps 4. geochemistry data 5. geophysical data To determine data coverage, metadata for exploration data (including data type, data status, and coverage information) were collected and catalogued from nodes on the National Geothermal Data System (NGDS). It is the intention of this analysis that the data be updated from this source in a semi-automated fashion as new datasets are added to the NGDS nodes. In addition to this upload, an online tool was developed to allow all geothermal data providers to access this assessment and to directly add metadata themselves and view the results of the analysis via maps of data coverage in Geothermal Prospector (http://maps.nrel.gov/gt_prospector). A grid of the contiguous U.S. was created with 88,000 10-km by 10-km grid cells, and each cell was populated with the status of data availability corresponding to the five data types. Using these five data coverage maps and the USGS Resource Potential Map, sites were identified for future data collection efforts. These sites signify both that the USGS has indicated high favorability of occurrence of geothermal resources and that data gaps exist. The uploaded data are contained in two data files for each data category. The first file contains the grid and is in the SHP file format (shape file.) Each populated grid cell represents a 10k area within which data is known to exist. The second file is a CSV (comma separated value) file that contains all of the individual layers that intersected with the grid. This CSV can be joined with the map to retrieve a list of datasets that are available at any given site. The attributes in the CSV include: 1. grid_id : The id of the grid cell that the data intersects with 2. title: This represents the name of the WFS service that intersected with this grid cell 3. abstract: This represents the description of the WFS service that intersected with this grid cell 4. gap_type: This represents the category of data availability that these data fall within. As the current processing is pulling data from NGDS, this category universally represents data that are available in the NGDS and are ready for acquisition for analytic purposes. 5. proprietary_type: Whether the data are considered proprietary 6. service_type: The type of service 7. base_url: The service URL

Getman, Dan

2013-09-30T23:59:59.000Z

230

The refractive index and electronic gap of water and ice increase with increasing pressure  

E-Print Network [OSTI]

Determining the electronic and dielectric properties of water at high pressure and temperature is an essential prerequisite to understand the physical and chemical properties of aqueous environments under supercritical conditions, e.g. in the Earth interior. However optical measurements of compressed ice and water remain challenging and it has been common practice to assume that their band gap is inversely correlated to the measured refractive index, consistent with observations reported for hundreds of materials. Here we report ab initio molecular dynamics and electronic structure calculations showing that both the refractive index and the electronic gap of water and ice increase with pressure, at least up to 30 GPa. Subtle electronic effects, related to the nature of interband transitions and band edge localization under pressure, are responsible for this apparently anomalous behavior.

Pan, Ding; Galli, Giulia

2014-01-01T23:59:59.000Z

231

Drop short control of electrode gap  

DOE Patents [OSTI]

During vacuum consumable arc remelting the electrode gap between a consumable electrode and a pool of molten metal is difficult to control. The present invention monitors drop shorts by detecting a decrease in the voltage between the consumable electrode and molten pool. The drop shorts and their associated voltage reductions occur as repetitive pulses which are closely correlated to the electrode gap. Thus, the method and apparatus of the present invention controls electrode gap based upon drop shorts detected from the monitored anode-cathode voltage. The number of drop shorts are accumulated, and each time the number of drop shorts reach a predetermined number, the average period between drop shorts is calculated from this predetermined number and the time in which this number is accumulated. This average drop short period is used in a drop short period electrode gap model which determines the actual electrode gap from the drop short. The actual electrode gap is then compared with a desired electrode gap which is selected to produce optimum operating conditions and the velocity of the consumable error is varied based upon the gap error. The consumable electrode is driven according to any prior art system at this velocity. In the preferred embodiment, a microprocessor system is utilized to perform the necessary calculations and further to monitor the duration of each drop short. If any drop short exceeds a preset duration period, the consumable electrode is rapidly retracted a predetermined distance to prevent bonding of the consumable electrode to the molten remelt.

Fisher, Robert W. (Albuquerque, NM); Maroone, James P. (Albuquerque, NM); Tipping, Donald W. (Albuquerque, NM); Zanner, Frank J. (Sandia Park, NM)

1986-01-01T23:59:59.000Z

232

A method for calculating wide band electromagnetic interference from power line corona  

SciTech Connect (OSTI)

An algorithm for calculating electromagnetic interference from power line corona for a range of frequencies from 100 kHz to 30 MHz is demonstrated. It can be used for calculations at any distance or direction from the line. The algorithm incorporates an existing generation function which has been optimized by comparison to long term electromagnetic interference measurements.

Olsen, R.G. [Washington State Univ., Pullman, WA (United States). School of Electrical Engineering and Computer Science] [Washington State Univ., Pullman, WA (United States). School of Electrical Engineering and Computer Science; Schennum, S.D. [Gonzaga Univ., Spokane, WA (United States)] [Gonzaga Univ., Spokane, WA (United States)

1995-07-01T23:59:59.000Z

233

2D pore-scale simulation of wide-band electromagnetic dispersion of saturated rocks  

E-Print Network [OSTI]

Engineering,Austin,Texas; presently Chevron NorthAmerica Exploration and Production, Houston,Texas. E dispersion of saturated rocks. INTRODUCTION Maxwell-Wagner interfacial polarization process The complex,Austin,Texas. E-mail: cverdin@mail.utexas.edu. © 2007 Society of Exploration Geophysicists.All rights reserved

Torres-VerdĂ­n, Carlos

234

Physical-Layer Security: Wide-band Communications & Role of Known Interference  

E-Print Network [OSTI]

to achieve the secrecy capacity of the degraded Gaussian model (dubbed as “secret writing on dirty paper”) to within half a bit. The success of this approach allowed its application to the problem of “secret key agreement via dirty paper coding...

El-Halabi, Mustapha

2013-12-05T23:59:59.000Z

235

On the vortex parameter estimation using wide band signals in active acoustic system  

E-Print Network [OSTI]

is an important operation in a large number of applications such as turbine monitoring, de- tection of a vortex in a closed hydraulic test loop. The objective of the work is to emphasize the effect

Paris-Sud XI, Université de

236

Engine piston having an insulating air gap  

DOE Patents [OSTI]

A piston for an internal combustion engine has an upper crown with a top and a bottom surface, and a lower crown with a top and a bottom surface. The upper crown and the lower crown are fixedly attached to each other using welds, with the bottom surface of the upper crown and the top surface of the lower crown forming a mating surface. The piston also has at least one centrally located air gap formed on the mating surface. The air gap is sealed to prevent substantial airflow into or out of the air gap.

Jarrett, Mark Wayne (Washington, IL); Hunold,Brent Michael (Apex, NC)

2010-02-02T23:59:59.000Z

237

Are We Closing the School Discipline Gap?  

E-Print Network [OSTI]

D.J. , (Ed). Closing the School Discipline Gap: EquitableBooth, E.A. (2011). Breaking schools’ rules: A statewidestudy of how school discipline relates to students’ success

Losen, Daniel; Hodson, Cheri; Keith II, Michael A; Morrison, Katrina; Belway, Shakti

2015-01-01T23:59:59.000Z

238

GaNAsP: An intermediate band semiconductor grown by gas-source molecular beam epitaxy  

SciTech Connect (OSTI)

Dilute nitride GaNAsP thin films were grown via a GaAsP metamorphic buffer on GaP(100) substrate with gas-source molecular beam epitaxy. The compositions of this III-V-V-V compound were determined by channeling Rutherford backscattering spectroscopy and nuclear reaction analysis. Photoreflectance shows two distinctive transitions from the valence band to the split conduction bands due to N incorporation. Photoluminescence and optical absorption show the fundamental bandgap of Ga(N)AsP is largely tailored by the small amount of N. The observed multiband characteristics and the bandgap tunability of GaNAsP are two merits that fit into the intermediate-band solar cell roadmap, and GaNAsP of high crystal quality provides a strong candidate for intermediate band solar cell materials.

Kuang, Y. J. [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States)] [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States); Yu, K. M.; Walukiewicz, W. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kudrawiec, R. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States) [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Institute of Physics, Wroclaw University of Technology, Wybrzeze, Wyspianskiego 27, 50-370 Wroclaw (Poland); Luce, A. V. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States) [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Ting, M. [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States)] [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States); Tu, C. W. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)] [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

2013-03-18T23:59:59.000Z

239

On the K{sup {pi}} = 0{sup +} rotational bands in the {sup 178}Hf nucleus  

SciTech Connect (OSTI)

The results obtained by studying the angular distributions of gamma rays with respect to the neutron-beam axis in the reaction {sup 178}Hf(n, n'{gamma}) involving the deexcitation of the K{sup {pi}} = 0{sup +} rotational bands of {sup 178}Hf are presented.New information about themultipole-mixing parameter {delta} in gamma transitions from the levels of these bands is obtained. The K{sup {pi}} = 0{sub 4}{sup +} band is constructed anew. The relationship between the parameter {delta} for the (2{sup +}0{sub n}-2{sup +}0{sub 1}) gamma transition and the energy gap {Delta}{sub n} = E{sub lev}(2{sup +}0{sub n}) - E{sub lev}(0{sup +}0{sub n}), on one hand, and the quasiparticle structure of the rotational band, on the other hand, is discussed for {sup 178}Hf on the basis of the quasiparticle-phonon model.

Govor, L. I.; Demidov, A. M.; Kurkin, V. A., E-mail: kurkin@polyn.kiae.su; Mikhailov, I. V. [Russian Research Centre Kurchatov Institute (Russian Federation)

2010-07-15T23:59:59.000Z

240

Columbia River Component Data Gap Analysis  

SciTech Connect (OSTI)

This Data Gap Analysis report documents the results of a study conducted by Washington Closure Hanford (WCH) to compile and reivew the currently available surface water and sediment data for the Columbia River near and downstream of the Hanford Site. This Data Gap Analysis study was conducted to review the adequacy of the existing surface water and sediment data set from the Columbia River, with specific reference to the use of the data in future site characterization and screening level risk assessments.

L. C. Hulstrom

2007-10-23T23:59:59.000Z

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


241

Beam dumping system and abort gap  

E-Print Network [OSTI]

The performance of the beam dumping systems and the abort gap cleaning are reviewed in the context of the general machine protection system. Details of the commissioning experience and setting up, encountered equipment problems, the experience with and status of the eXternal Post Operational Checks (XPOC) and the importance of operational procedures are presented for the beam dumping system. The brief experience with the abort gap cleaning is also presented.

Uythoven, J

2010-01-01T23:59:59.000Z

242

Wide field of view telescope  

DOE Patents [OSTI]

A wide field of view telescope having two concave and two convex reflective surfaces, each with an aspheric surface contour, has a flat focal plane array. Each of the primary, secondary, tertiary, and quaternary reflective surfaces are rotationally symmetric about the optical axis. The combination of the reflective surfaces results in a wide field of view in the range of approximately 3.8.degree. to approximately 6.5.degree.. The length of the telescope along the optical axis is approximately equal to or less than the diameter of the largest of the reflective surfaces.

Ackermann, Mark R. (Albuquerque, NM); McGraw, John T. (Placitas, NM); Zimmer, Peter C. (Albuquerque, NM)

2008-01-15T23:59:59.000Z

243

NWChem: Bridging the Gap Between Experimental and Computational...  

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

NWChem: Bridging the Gap Between Experimental and Computational Chemistry NWChem: Bridging the Gap Between Experimental and Computational Chemistry Intel recently interviewed...

244

antiparticle spectrometer gaps: Topics by E-print Network  

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

Next Page Last Page Topic Index 1 The General Antiparticle Spectrometer (GAPS) - Hunt for dark matter using low-energy antideuterons CERN Preprints Summary: The GAPS experiment is...

245

Bridging the Gap between Fundamental Physics and Chemistry and...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Bridging the Gap between Fundamental Physics and Chemistry and Applied Models for HCCI Engines Bridging the Gap between Fundamental Physics and Chemistry and Applied Models for...

246

SOFTWAREENGINEERING The World Wide Web  

E-Print Network [OSTI]

SOFTWAREENGINEERING The World Wide Web Distributed Authoring and Versioning working group on the Web. WEBDAV: IETF Standard for Collaborative Authoring on the Web E. JAMES WHITEHEAD, JR. University remains to be done. What if instead you could simply edit Web documents (or any Web resource) in place

Whitehead, James

247

Energy band modulation of graphane by hydrogen-vacancy chains: A first-principles study  

SciTech Connect (OSTI)

We investigated a variety of configurations of hydrogen-vacancy chains in graphane by first-principles density functional calculation. We found that graphane with two zigzag H-vacancy chains segregated by one or more H chain is generally a nonmagnetic conductor or has a negligible band gap. However, the same structure is turned into a semiconductor and generates a magnetic moment if either one or both of the vacancy chains are blocked by isolated H atoms. If H-vacancy chains are continuously distributed, the structure is similar to a zigzag graphene nanoribbon embedded in graphane. It was also found that the embedded zigzag graphene nanoribbon is antiferromagnetic, and isolated H atoms left in the 2-chain nanoribbon can tune the band gap and generate net magnetic moments. Similar effects are also obtained if bare carbon atoms are present outside the nanoribbon. These results are useful for designing graphene-based nanoelectronic circuits.

Wu, Bi-Ru [Department of Natural science, Center for General Education, Chang Gung University, Kueishan 333, Taiwan, ROC (China); Yang, Chih-Kai, E-mail: ckyang@nccu.edu.tw [Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan, ROC (China)

2014-08-15T23:59:59.000Z

248

Wide Bandgap Extrinsic Photoconductive Switches  

SciTech Connect (OSTI)

Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

Sullivan, J S

2012-01-17T23:59:59.000Z

249

Magnetism and interaction-induced gap opening in graphene with vacancies or hydrogen adatoms: Quantum Monte Carlo study  

E-Print Network [OSTI]

We study electronic properties of graphene with finite concentration of vacancies or other resonant scatterers by a straightforward lattice Quantum Monte Carlo calculations. Taking into account realistic long-range Coulomb interaction we calculate distribution of spin density associated to midgap states and demonstrate antiferromagnetic ordering. Energy gap are open due to the interaction effects, both in the bare graphene spectrum and in the vacancy/impurity bands. In the case of 5 % concentration of resonant scatterers the latter gap is estimated as 0.7 eV and 1.1 eV for graphene on boron nitride and freely suspended graphene, respectively.

M. V. Ulybyshev; M. I. Katsnelson

2015-02-04T23:59:59.000Z

250

Magnetism and interaction-induced gap opening in graphene with vacancies or hydrogen adatoms: Quantum Monte Carlo study  

E-Print Network [OSTI]

We study electronic properties of graphene with finite concentration of vacancies or other resonant scatterers by a straightforward lattice Quantum Monte Carlo calculations. Taking into account realistic long-range Coulomb interaction we calculate distribution of spin density associated to midgap states and demonstrate antiferromagnetic ordering. Energy gap are open due to the interaction effects, both in the bare graphene spectrum and in the vacancy/impurity bands. In the case of 5 % concentration of resonant scatterers the latter gap is estimated as 0.7 eV and 1.1 eV for graphene on boron nitride and freely suspended graphene, respectively.

Ulybyshev, M V

2015-01-01T23:59:59.000Z

251

Hanford Waste Physical and Rheological Properties: Data and Gaps  

SciTech Connect (OSTI)

The retrieval, transport, treatment and disposal operations associated with Hanford Tank Wastes involve the handling of a wide range of slurries. Knowledge of the physical and rheological properties of the waste is a key component to the success of the design and implementation of the waste processing facilities. Previous efforts to compile and analyze the physical and rheological properties were updated with new results including information on solids composition and density, particle size distributions, slurry rheology, and particle settling behavior. The primary source of additional data is from a recent series of tests sponsored by the Hanford Waste Treatment and Immobilization Plant. These tests involved an extensive suite of characterization and bench-scale process testing of 8 waste groups representing approximately 75% of the high-level waste mass expected to be processed through the WTP. Additional information on the morphology of the waste solids was also included. Based on the updated results, a gap analysis to identify gaps in characterization data, analytical methods and data interpretation was completed.

Kurath, Dean E.; Wells, Beric E.; Huckaby, James L.; Mahoney, Lenna A.; Daniel, Richard C.; Burns, Carolyn A.; Tingey, Joel M.; Cooley, Scott K.

2012-03-01T23:59:59.000Z

252

Hanford Waste Physical and Rheological Properties: Data and Gaps - 12078  

SciTech Connect (OSTI)

The retrieval, transport, treatment and disposal operations associated with Hanford Tank Wastes involve the handling of a wide range of slurries. Knowledge of the physical and rheological properties of the waste is a key component to the success of the design and implementation of the waste processing facilities. Previous efforts to compile and analyze the physical and rheological properties were updated with new results including information on solids composition and density, particle size distributions, slurry rheology, and particle settling behavior. The primary source of additional data is from a recent series of tests sponsored by the Hanford Waste Treatment and Immobilization Plant (WTP). These tests involved an extensive suite of characterization and bench-scale process testing of 8 waste groups representing approximately 75% of the high-level waste mass expected to be processed through the WTP. Additional information on the morphology of the waste solids was also included. Based on the updated results, a gap analysis to identify gaps in characterization data, analytical methods and data interpretation was completed. (authors)

Kurath, D.E.; Wells, B.E.; Huckaby, J.L.; Mahoney, L.A.; Daniel, R.C.; Burns, C.A.; Tingey, J.M.; Cooley, S.K. [Pacific Northwest National Laboratory PO Box 999, Richland WA 99352 (United States)

2012-07-01T23:59:59.000Z

253

Heterojunction band offsets and dipole formation at BaTiO{sub 3}/SrTiO{sub 3} interfaces  

SciTech Connect (OSTI)

We used a complement of photoemission and cathodoluminescence techniques to measure formation of the BaTiO{sub 3} (BTO) on SrTiO{sub 3} (STO) heterojunction band offset grown monolayer by monolayer by molecular beam epitaxy. X-ray photoemission spectroscopy (XPS) provided core level and valence band edge energies to monitor the valence band offset in-situ as the first few crystalline BTO monolayers formed on the STO substrate. Ultraviolet photoemission spectroscopy (UPS) measured Fermi level positions within the band gap, work functions, and ionization potentials of the growing BTO film. Depth-resolved cathodoluminescence spectroscopy measured energies and densities of interface states at the buried heterojunction. Kraut-based XPS heterojunction band offsets provided evidence for STO/BTO heterojunction linearity, i.e., commutativity and transitivity. In contrast, UPS and XPS revealed a large dipole associated either with local charge transfer or strain-induced polarization within the BTO epilayer.

Balaz, Snjezana [Department of Physics and Astronomy, Youngstown State University, One University Plaza, Youngstown, Ohio 44555 (United States)] [Department of Physics and Astronomy, Youngstown State University, One University Plaza, Youngstown, Ohio 44555 (United States); Zeng, Zhaoquan [Department of Electrical and Computer Engineering, The Ohio State University, 205 Dreese Lab, 2015 Neil Ave., Columbus, Ohio 43210 (United States)] [Department of Electrical and Computer Engineering, The Ohio State University, 205 Dreese Lab, 2015 Neil Ave., Columbus, Ohio 43210 (United States); Brillson, Leonard J. [Department of Electrical and Computer Engineering, The Ohio State University, 205 Dreese Lab, 2015 Neil Ave., Columbus, Ohio 43210 (United States) [Department of Electrical and Computer Engineering, The Ohio State University, 205 Dreese Lab, 2015 Neil Ave., Columbus, Ohio 43210 (United States); Department of Physics, The Ohio State University, 191 West Woodruff, Columbus, Ohio 43210 (United States)

2013-11-14T23:59:59.000Z

254

A University of Alabama Axial-Gap Electric Motor Developmenty  

E-Print Network [OSTI]

CAVT A University of Alabama Axial-Gap Electric Motor Developmenty Research Center OBJECTIVE ­ Develop axial gap permanent-magnet electric Axial motor ­ Develop axial gap permanent-magnet electric motor topologies with high torque and power densities MOTIVATION ­ Axial-gap ("pancake") motors have

Carver, Jeffrey C.

255

Oscillation of Fourier Integrals with a spectral gap  

E-Print Network [OSTI]

May 30, 2003 ... In engineering literature, functions with a spectral gap are called high- .... High-

1910-30-71T23:59:59.000Z

256

Natural Gas Engine Development Gaps (Presentation)  

SciTech Connect (OSTI)

A review of current natural gas vehicle offerings is presented for both light-duty and medium- and heavy-duty applications. Recent gaps in the marketplace are discussed, along with how they have been or may be addressed. The stakeholder input process for guiding research and development needs via the Natural Gas Vehicle Technology Forum (NGVTF) to the U.S. Department of Energy and the California Energy Commission is reviewed. Current high-level natural gas engine development gap areas are highlighted, including efficiency, emissions, and the certification process.

Zigler, B.T.

2014-03-01T23:59:59.000Z

257

Homolumo gap from dynamical energy levels  

SciTech Connect (OSTI)

We introduce a dynamical matrix model where the matrix is interpreted as a Hamiltonian representing interaction of a bosonic system with a single fermion. We show how a system of second-quantized fermions influences the ground state of the whole system by producing a gap between the highest eigenvalue of the occupied single-fermion states and the lowest eigenvalue of the unoccupied single-fermion states. We describe the development of the gap in both the strong and weak coupling regimes, while for the intermediate coupling strength we expect formation of homolumo kinks.

Andric, I.; Jonke, L.; Jurman, D.; Nielsen, H. B. [Theoretical Physics Division, Rudjer Boskovic Institute, P.O. Box 180, 10002 Zagreb (Croatia); Niels Bohr Institute, Copenhagen DK 2100 (Denmark)

2009-11-15T23:59:59.000Z

258

Transient Shear Banding in a Simple Yield Stress Fluid Thibaut Divoux,1  

E-Print Network [OSTI]

region with a vanishing local shear rate loc = 0 and a fluidized region sheared at loc = c. Besides, var that somewhat blur the above distinction. First, non-thixotropic nonad- hesive emulsions, for which magnetic resonance velocime- try coupled to wide-gap rheology shows simple yielding behavior [12], were found

Paris-Sud XI, Université de

259

Parametric representation of wave propagation in nonuniform media (both in transmission and stop bands)  

E-Print Network [OSTI]

An analytical approach based on the parametric representation of the wave propagation in nonuniform media was considered. In addition to the previously developed theory of parametric antiresonance describing the field attenuation in stop bands, in the present paper the behaviour of the Bloch wave in a transmission band was investigated. A wide class of exact solutions was found and the correspondence to the quasi-periodic Floquet solutions was shown.

A. Popov; V. Kovalchuk

2011-12-06T23:59:59.000Z

260

Red Band Needle Blight TERMS OF REFERENCE  

E-Print Network [OSTI]

Red Band Needle Blight TERMS OF REFERENCE Purpose 1. The Programme Board has been formed to have an overview of the administration and science of Red Band Needle Blight (RBNB), to underpin decisions made

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


261

Opportunities for Wide Bandgap Semiconductor Power Electronics...  

Energy Savers [EERE]

Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen...

262

Geology of the Wallula Gap Area, Washington. [Grande Ronde, Wanapum, and Saddle Mountains basalts  

SciTech Connect (OSTI)

This study focuses on the structure and stratigraphy of an 80-km/sup 2/ area at the southern margin of the Pasco Basin in Wallula Gap. Field stratigraphy, petrography, natural remanent magnetism, and major-element chemistry indicate that the tholeiitic basalt flows of the Wallula Gap area correlate with units of the Grande Ronde, Wanapum, and Saddle Mountains Formations of the Yakima Subgroup of the Columbia River Basalt Group. Flows of the Frenchman Springs, Umatilla, Pomona, Elephant Mountain, and Ice Harbor Mmebers are present in the area. The Frenchman Springs Member exposed in the Wallula Gap is more than 185 m thick and consists of eight to nine flows. Its thickness and possible contemporaneous structural deformation apparently prevented emplacement of both the Roza and Priest Rapids Members at this locality. Structural uplift of the Horse Heaven Hills began prior to extrusion of the Pomona flow. Both the Pomona and Elephant Mountain Members thin and pinch out over the crest of the uplift near Mound Pond. The Ice Harbor flow was apparently confined to the basin north of the Horse Heaven uplift, but an exposure at Mound Pond suggests it flowed through Wallula Gap as an intracanyon flow. The Wallula Gap fault zone trends N65/sup 0/W and can be traced for at least 11 km along the north flank of the Horse Heaven Hills uplift. Where the fault intersects the Olympic-Wallowa Lineament at Van Sycle Canyon 8 km east of Wallula Gap, it is a broad zone of normal faulting, 300 m wide, with as much as 310 m of displacement of the basalt stratigraphy. Two faults occur in the northern portion of Van Sycle Canyon and define a graben trending N45/sup 0/W. A third fault, roughly parallel to the Wallula Gap fault, transects the The Nub and offsets 14 m of Ice Harbor basalt.

Gardner, J.N.; Snow, M.G.; Fecht, K.R.

1981-12-01T23:59:59.000Z

263

FINAL REPORT ON GDE GAP CELL  

SciTech Connect (OSTI)

A project has been undertaken to develop an electrochemical cell and support equipment for evaluation of a gas diffusion electrode-based, narrow-electrolyte-gap anode for SO{sub 2} oxidation in the hydrogen production cycle of the hybrid sulfur (HyS) process. The project supported the HyS development program at the Savannah River National Lab (SRNL). The benefits of using a gas diffusion electrode in conjunction with the narrow anolyte gap are being determined through electrochemical polarization testing under a variety conditions, and by comparison to results produced by SRNL and others using anode technologies that have no anolyte gap. These test results indicate that the NGA cell has low resistance suitable for use in the HyS electrolyzer, exhibits good efficiency at high current densities compared to the direct feed HyS electrolyzer, and indicates robust performance in extended testing over 65 hours. Seepage episodes were mostly caused by port clogging, which can be mitigated in future designs through minor modifications to the hardware. Significant reductions in sulfur crossover have not yet been demonstrated in the NGA configuration compared to in-house direct feed testing, but corroborative sulfur layer analysis is as yet incomplete. Further testing in a single-pass anolyte configuration is recommended for complete evaluation of steady-state electrochemical efficiency and SO{sub 2} crossover in the narrow gap configuration.

Herman, D.; Summers, W.; Danko, E.

2009-09-28T23:59:59.000Z

264

Gapped spin Hamiltonian motivated by quantum teleportation  

E-Print Network [OSTI]

We construct a Hamiltonian whose ground state encodes a time-independent emulation of quan- tum teleportation. We calculate properties of the Hamiltonian, using exact diagonalization and a mean-field theory, and argue that it has a gap. The system exhibits an illuminating relationship to the well-known AKLT (Affleck, Lieb, Kennedy and Tasaki) model.

Ari Mizel

2014-10-07T23:59:59.000Z

265

An Aharonov-Bohm interferometer for determining Bloch band topology  

E-Print Network [OSTI]

The geometric structure of an energy band in a solid is fundamental for a wide range of many-body phenomena in condensed matter and is uniquely characterized by the distribution of Berry curvature over the Brillouin zone. In analogy to an Aharonov-Bohm interferometer that measures the magnetic flux penetrating a given area in real space, we realize an atomic interferometer to measure Berry flux in momentum space. We demonstrate the interferometer for a graphene-type hexagonal lattice, where it has allowed us to directly detect the singular $\\pi$ Berry flux localized at each Dirac point. We show that the interferometer enables one to determine the distribution of Berry curvature with high momentum resolution. Our work forms the basis for a general framework to fully characterize topological band structures and can also facilitate holonomic quantum computing through controlled exploitation of the geometry of Hilbert space.

Lucia Duca; Tracy Li; Martin Reitter; Immanuel Bloch; Monika Schleier-Smith; Ulrich Schneider

2014-07-21T23:59:59.000Z

266

Red Band Needle Blight Programme Red Band Needle Blight of Pine Programme Group  

E-Print Network [OSTI]

Red Band Needle Blight Programme Group Red Band Needle Blight of Pine Programme Group Minutes Support Welcome and introduction 1. Jim thanked everyone for attending the first meeting of the Red Band and that the private 1 | Paper 1 - Minutes | Debbie Erskine | 23/01/2009 #12;Red Band Needle Blight Programme Group

267

Confirmation of intrinsic electron gap states at nonpolar GaN(1-100) surfaces combining photoelectron and surface optical spectroscopy  

SciTech Connect (OSTI)

The electronic structure of GaN(1–100) surfaces is investigated in-situ by photoelectron spectroscopy (PES) and reflection anisotropy spectroscopy (RAS). Occupied surface states 3.1?eV below the Fermi energy are observed by PES, accompanied by surface optical transitions found in RAS around 3.3?eV, i.e., below the bulk band gap. These results indicate that the GaN(1–100) surface band gap is smaller than the bulk one due to the existence of intra-gap states, in agreement with density functional theory calculations. Furthermore, the experiments demonstrate that RAS can be applied for optical surface studies of anisotropic crystals.

Himmerlich, M., E-mail: marcel.himmerlich@tu-ilmenau.de; Eisenhardt, A.; Shokhovets, S.; Krischok, S. [Institut für Physik and Institut für Mikro- und Nanotechnologien, TU Ilmenau, PF 100565, 98684 Ilmenau (Germany); Räthel, J.; Speiser, E.; Neumann, M. D.; Navarro-Quezada, A.; Esser, N. [Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Albert-Einstein-Strasse 9, 12489 Berlin (Germany)

2014-04-28T23:59:59.000Z

268

Results of the GAP-4 experiment on molten-fuel drainage through intersubassembly gap geometry. [LMFBR  

SciTech Connect (OSTI)

One of the key issues in assessment of the meltout phase of a hypothetical core disruptive accident in the LMFBR system involves the timing and paths for dispersal of molten fuel from the disrupted core. A program of experiments is underway at Argonne National Laboratory to investigate molten fuel penetration through these postulated escape paths. The purpose of the GAP-4 test was to examine the penetration distances of molten fuel flowing through the flat, narrow channels representing the intersubassembly gap geometry. In the experiment design, the gap geometry was selected to be two-dimensional on the basis that the gap volume in a reactor design would be interconnected and continuous. The molten fuel used in these tests was a mixture of UO/sub 2/ (81%) and molybdenum (19%) which was generated by an exothermic thermite reaction at a temperature of approx. 3470 K.

Spencer, B.W.; Vetter, D.; Wesel, R.; Sienicki, J.J.

1983-01-01T23:59:59.000Z

269

Comparison of GAP-3 and GAP-4 experiments with conduction freezing calculations. [LMFBR  

SciTech Connect (OSTI)

Experiments GAP-3 and GAP-4 were performed at ANL to investigate the ability of molten fuel to penetrate downward through the narrow channels separating adjacent subassemblies during an LMFBR hypothetical core disruptive accident. Molten fuel-metal mixtures (81% UO/sub 2/, 19% Mo) at an initial temperature of 3470/sup 0/K generated by a thermite reaction were injected downward into 1 m long rectangular test sections (gap thickness = 0.43 cm, channel width = 20.3 cm) initially at 1170/sup 0/K simulating the nominal Clinch River Breeder Reactor intersubassembly gap. In the GAP-3 test, a prolonged reaction time of approx. 15 s resulted in segregation of the metallic Mo and oxidic UO/sub 2/ constituents within the reaction vessel prior to injection. Consequently, Mo entered the test section first and froze, forming a complete plug at a penetration distance of 0.18 m. In GAP-4, the reaction time was reduced to approx. 3 s and the constituents remained well mixed upon injection with the result that the leading edge penetration distance increased to 0.35 m. Posttest examination of the cut-open test sections has revealed the existence of stable insulating crusts upon the underlying steel walls with melting and ablation of the walls only very localized.

Sienicki, J.J.; Spencer, B.W.

1983-01-01T23:59:59.000Z

270

Thickness-modulated optical dielectric constants and band alignments of HfO{sub x}N{sub y} gate dielectrics  

SciTech Connect (OSTI)

Thickness-modulated optical dielectric constants and band alignments of HfO{sub x}N{sub y} films grown by sputtering have been investigated by spectroscopic ellipsometry (SE) and x-ray photoelectron spectroscopy. Based on SE measurements, it has been noted that an increase in optical dielectric constant and band gap has been observed as a function of the film thickness. Analyses of thickness-dependent band alignment of the HfO{sub x}N{sub y}/Si system indicate that the valence band offset increases, but only slight change in the conduction band offset, resulting from the thickness-induced change in the structure. The suitable optical dielectric constants and band offsets relative to Si make sputtering-derived HfO{sub x}N{sub y} film a promising candidate for high-k gate dielectrics.

He, G.; Zhang, L. D.; Liu, M.; Zhang, J. P.; Wang, X. J. [Key Laboratory of Materials Physics, Anhui Key Laboratory of Nanomaterials and Nanostructure, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhen, C. M. [Department of Physics, Hebei Advanced Thin Films Laboratory, Hebei Normal University, Shijiazhuang 050016 (China)

2009-01-01T23:59:59.000Z

271

Ka-Band ARM Zenith Radar (KAZR) Instrument Handbook  

SciTech Connect (OSTI)

The Ka-band ARM zenith radar (KAZR) is a zenith-pointing Doppler cloud radar operating at approximately 35 GHz. The KAZR is an evolutionary follow-on radar to ARM's widely successful millimeter-wavelength cloud radar (MMCR). The main purpose of the KAZR is to provide vertical profiles of clouds by measuring the first three Doppler moments: reflectivity, radial Doppler velocity, and spectra width. At the sites where the dual-polarization measurements are made, the Doppler moments for the cross-polarization channel are also available. In addition to the moments, velocity spectra are also continuously recorded for each range gate.

Widener, K; Bharadwaj, N; Johnson, K

2012-03-06T23:59:59.000Z

272

VIMOS total transmission profiles for broad-band filters  

E-Print Network [OSTI]

VIMOS is a wide-field imager and spectrograph mounted on UT3 at the VLT, whose FOV consists of four 7'x8' quadrants. Here we present the measurements of total transmission profiles -- i.e. the throughput of telescope + instrument -- for the broad band filters U, B, V, R, I, and z for each of its four quadrants. Those measurements can also be downloaded from the public VIMOS web-page. The transmission profiles are compared with previous estimates from the VIMOS consortium.

S. Mieske; M. Rejkuba; S. Bagnulo; C. Izzo; G. Marconi

2007-04-13T23:59:59.000Z

273

On fixed-gap adiabatic quantum computation  

E-Print Network [OSTI]

Quantum computation has revolutionary potential for speeding algorithms and for simulating quantum systems such as molecules. We report here a quantum computer design that performs universal quantum computation within a single non-degenerate ground state protected from decohering noise by an energy gap that we argue is system-size-independent. Closely analogous to a traditional electric circuit, it substantially changes the requirements for quantum computer construction, easing measurement, timing, and heating problems. Using the standard adiabatic condition, we present evidence that this design permits "quantum concurrent processing" distributing a quantum computation among extra qubits to perform a quantum algorithm of N gates in an amount of time that scales with the square root of N. One consequence of our work is a fixed gap version of adiabatic quantum computation, which several arguments hinted could be impossible.

Ari Mizel

2014-01-21T23:59:59.000Z

274

Chemical potential and the gap equation  

E-Print Network [OSTI]

In general the kernel of QCD's gap equation possesses a domain of analyticity upon which the equation's solution at nonzero chemical potential is simply obtained from the in-vacuum result through analytic continuation. On this domain the single-quark number- and scalar-density distribution functions are mu-independent. This is illustrated via two models for the gap equation's kernel. The models are alike in concentrating support in the infrared. They differ in the form of the vertex but qualitatively the results are largely insensitive to the Ansatz. In vacuum both models realise chiral symmetry in the Nambu-Goldstone mode and in the chiral limit, with increasing chemical potential, exhibit a first-order chiral symmetry restoring transition at mu~M(0), where M(p^2) is the dressed-quark mass function. There is evidence to suggest that any associated deconfinement transition is coincident and also of first-order.

Huan Chen; Wei Yuan; Lei Chang; Yu-Xin Liu; Thomas Klahn; Craig D. Roberts

2008-07-17T23:59:59.000Z

275

SHEEP MOUNTAIN URANIUM PROJECT CROOKS GAP, WYOMING  

E-Print Network [OSTI]

;PROJECT OVERVIEW ·Site Location·Site Location ·Fremont , Wyoming ·Existing Uranium Mine Permit 381C·Existing Uranium Mine Permit 381C ·Historical Operation ·Western Nuclear Crooks Gap Project ·Mined 1956 ­ 1988 and Open Pit Mining ·Current Mine Permit (381C) ·Updating POO, Reclamation Plan & Bond ·Uranium Recovery

276

Vehicle Codes and Standards: Overview and Gap Analysis  

SciTech Connect (OSTI)

This report identifies gaps in vehicle codes and standards and recommends ways to fill the gaps, focusing on six alternative fuels: biodiesel, natural gas, electricity, ethanol, hydrogen, and propane.

Blake, C.; Buttner, W.; Rivkin, C.

2010-02-01T23:59:59.000Z

277

Bridging the Efficiency Gap: Commercial Packaged Rooftop Air Conditioners  

E-Print Network [OSTI]

Bridging the Efficiency Gap: Commercial Packaged Rooftop Air Conditioners John Shugars, Consultant ofcommercialpackaged air conditioners, explore the reasons behindthis efficiency gap, and assess opportunities). Although sales of rooftop air conditioners have steadily increased over the past decade, the efficiency

278

Proposal of high efficiency solar cells with closely stacked InAs/In{sub 0.48}Ga{sub 0.52}P quantum dot superlattices: Analysis of polarized absorption characteristics via intermediate–band  

SciTech Connect (OSTI)

We present a theoretical study of the electronic structures and polarized absorption properties of quantum dot superlattices (QDSLs) using wide–gap matrix material, InAs/In{sub 0.48}Ga{sub 0.52}P QDSLs, for realizing intermediate–band solar cells (IBSCs) with two–step photon–absorption. The plane–wave expanded Burt–Foreman operator ordered 8–band k·p theory is used for this calculation, where strain effect and piezoelectric effect are taken into account. We find that the absorption spectra of the second transitions of two–step photon–absorption can be shifted to higher energy region by using In{sub 0.48}Ga{sub 0.52}P, which is lattice–matched material to GaAs substrate, as a matrix material instead of GaAs. We also find that the transverse magnetic polarized absorption spectra in InAs/In{sub 0.48}Ga{sub 0.52}P QDSL with a separate IB from the rest of the conduction minibands can be shifted to higher energy region by decreasing the QD height. As a result, the second transitions of two–step photon–absorption by the sunlight occur efficiently. These results indicate that InAs/In{sub 0.48}Ga{sub 0.52}P QDSLs are suitable material combination of IBSCs toward the realization of ultrahigh efficiency solar cells.

Yoshikawa, H., E-mail: yoshikawa-hirofumi@sharp.co.jp; Kotani, T.; Kuzumoto, Y.; Izumi, M.; Tomomura, Y.; Hamaguchi, C. [Advanced Technology Research Laboratories, Sharp Corporation Tenri, Nara 632-8567 (Japan)

2014-07-07T23:59:59.000Z

279

X-BAND KLYSTRON DEVELOPMENT AT SLAC  

SciTech Connect (OSTI)

The development of X-band klystrons at SLAC originated with the idea of building an X-band Linear Collider in the late 1980's. Since then much effort has been expended in developing a reliable X-band Power source capable of delivering >50 MW RF power in pulse widths >1.5 {micro}s. I will report on some of the technical issues and design strategies which have led to the current SLAC klystron designs.

Vlieks, Arnold E.; /SLAC

2009-08-03T23:59:59.000Z

280

Possible chiral bands in {sup 194}Tl  

SciTech Connect (OSTI)

High spin states in {sup 194}Tl, excited through the {sup 181}Ta({sup 18}O,5n) fusion evaporation reaction, were studied using the AFRODITE array at iThemba LABS. Candidate chiral bands built on the {pi}h{sub 9/2} x {nu}i{sub 13/2}{sup 1} configuration were found. Furthermore these bands were observed through a band crossing caused by the excitation of a {nu}i{sub 13/2} pair. Above the band crossing the excitation energies remain close, suggesting that chirality may persist for the four quasiparticle configuration too.

Masiteng, P. L.; Ramashidzha, T. M.; Maliage, S. M.; Sharpey-Schafer, J. F.; Vymers, P. A. [iThemba LABS, P.O Box 722, 7129 (South Africa); University of the Western Cape, Private Bag X17, 7535 Bellville (South Africa); Lawrie, E. A.; Lawrie, J. J.; Bark, R. A.; Mullins, S. M.; Murray, S. H. T. [iThemba LABS, P.O Box 722, 7129 (South Africa); Kau, J.; Komati, F. [iThemba LABS, P.O Box 722, 7129 (South Africa); University of the North West, Private Bag X2046, 2735 Mafikeng (South Africa); Lindsay, R. [University of the Western Cape, Private Bag X17, 7535 Bellville (South Africa); Matamba, I. [University of Venda for Science and Technology, Thohoyandou (South Africa); Mutshena, P. [iThemba LABS, P.O Box 722, 7129 (South Africa); University of Venda for Science and Technology, Thohoyandou (South Africa); Zhang, Y. [iThemba LABS, P.O Box 722, 7129 (South Africa); University of Cape Town, Private Bag, 7701 Rondebosch (South Africa)

2011-10-28T23:59:59.000Z

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


281

Ultra wide-bandwidth micro energy harvester  

E-Print Network [OSTI]

An ultra wide-bandwidth resonating thin film PZT MEMS energy harvester has been designed, modeled, fabricated and tested. It harvests energy from parasitic ambient vibration at a wide range of amplitude and frequency via ...

Hajati, Arman

2011-01-01T23:59:59.000Z

282

Composition dependent valence band order in c-oriented wurtzite AlGaN layers  

SciTech Connect (OSTI)

The valence band order of polar wurtzite aluminum gallium nitride (AlGaN) layers is analyzed for a dense series of samples, grown heteroepitaxially on sapphire substrates, covering the complete composition range. The excitonic transition energies, found by temperature dependent photoluminescence (PL) spectroscopy, were corrected to the unstrained state using input from X-ray diffraction. k?p theory yields a critical relative aluminum concentration x{sub c}=(0.09±0.05) for the crossing of the uppermost two valence bands for strain free material, shifting to higher values for compressively strained samples, as supported by polarization dependent PL. The analysis of the strain dependent valence band crossing reconciles the findings of other research groups, where sample strain was neglected. We found a bowing for the energy band gap to the valence band with ?{sub 9} symmetry of b{sub ?{sub 9}}=0.85eV, and propose a possible bowing for the crystal field energy of b{sub cf}=?0.12eV. A comparison of the light extraction efficiency perpendicular and parallel to the c axis of Al{sub x}Ga{sub 1-x}N/Al{sub y}Ga{sub 1-y}N quantum well structures is discussed for different compositions.

Neuschl, B., E-mail: benjamin.neuschl@uni-ulm.de; Helbing, J.; Knab, M.; Lauer, H.; Madel, M.; Thonke, K. [Institute of Quantum Matter / Semiconductor Physics Group, University of Ulm, Albert-Einstein-Allee 45, 89069 Ulm (Germany); Meisch, T.; Forghani, K.; Scholz, F. [Institute of Optoelectronics, University of Ulm, Albert-Einstein-Allee 45, 89069 Ulm (Germany); Feneberg, M. [Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg (Germany)

2014-09-21T23:59:59.000Z

283

Equivalent Circuit Description of Non-compensated n-p Codoped TiO2 as Intermediate Band Solar Cells  

E-Print Network [OSTI]

The novel concept of non-compensated n-p codoping has made it possible to create tunable intermediate bands in the intrinsic band gap of TiO2, making the codoped TiO2 a promising material for developing intermediate band solar cells (IBSCs). Here we investigate the quantum efficiency of such IBSCs within two scenarios - with and without current extracted from the extended intermediate band. Using the ideal equivalent circuit model, we find that the maximum efficiency of 57% in the first scenario and 53% in the second are both much higher than the Shockley-Queisser limit from single gap solar cells. We also obtain various key quantities of the circuits, a useful step in realistic development of TiO2 based solar cells invoking device integration. These equivalent circuit results are also compared with the efficiencies obtained directly from consideration of electron transition between the energy bands, and both approaches reveal the intriguing existence of double peaks in the maximum quantum efficiency as a function of the relative location of IBs.

Tian-Li Feng; Guang-Wei Deng; Yi Xia; Feng-Cheng Wu; Ping Cui; Hai-Ping Lan; Zhen-Yu Zhang

2010-12-09T23:59:59.000Z

284

Equivalent Circuit Description of Non-compensated n-p Codoped TiO2 as Intermediate Band Solar Cells  

E-Print Network [OSTI]

The novel concept of non-compensated n-p codoping has made it possible to create tunable intermediate bands in the intrinsic band gap of TiO2, making the codoped TiO2 a promising material for developing intermediate band solar cells (IBSCs). Here we investigate the quantum efficiency of such IBSCs within two scenarios - with and without current extracted from the extended intermediate band. Using the ideal equivalent circuit model, we find that the maximum efficiency of 57% in the first scenario and 53% in the second are both much higher than the Shockley-Queisser limit from single gap solar cells. We also obtain various key quantities of the circuits, a useful step in realistic development of TiO2 based solar cells invoking device integration. These equivalent circuit results are also compared with the efficiencies obtained directly from consideration of electron transition between the energy bands, and both approaches reveal the intriguing existence of double peaks in the maximum quantum efficiency as a fun...

Feng, Tian-Li; Xia, Yi; Wu, Feng-Cheng; Cui, Ping; Lan, Hai-Ping; Zhang, Zhen-Yu

2010-01-01T23:59:59.000Z

285

Note On The Maximal Primes Gaps  

E-Print Network [OSTI]

This note presents a result on the maximal prime gap of the form p_(n+1) - p_n 0 is a constant, for any arbitrarily small real number e > 0, and all sufficiently large integer n > n_0. Equivalently, the result shows that any short interval [x, x + y], y => C(log x)^(1+e), contains prime numbers for all sufficiently large real numbers x => x_0 unconditionally. An application demonstrates that a prime p => x > 2 can be determined in deterministic polynomial time O(log(x)^8).

N. A. Carella

2015-02-05T23:59:59.000Z

286

Turbine blade tip gap reduction system  

DOE Patents [OSTI]

A turbine blade sealing system for reducing a gap between a tip of a turbine blade and a stationary shroud of a turbine engine. The sealing system includes a plurality of flexible seal strips extending from a pressure side of a turbine blade generally orthogonal to the turbine blade. During operation of the turbine engine, the flexible seal strips flex radially outward extending towards the stationary shroud of the turbine engine, thereby reducing the leakage of air past the turbine blades and increasing the efficiency of the turbine engine.

Diakunchak, Ihor S.

2012-09-11T23:59:59.000Z

287

Complexified cones. Spectral gaps and variational principles  

E-Print Network [OSTI]

We consider contractions of complexified real cones, as recently introduced by Rugh in [Rugh10]. Dubois [Dub09] gave optimal conditions to determine if a matrix contracts a canonical complex cone. First we generalize his results to the case of complex operators on a Banach space and give precise conditions for the contraction and an improved estimate of the size of the associated spectral gap. We then prove a variational formula for the leading eigenvalue similar to the Collatz-Wielandt formula for a real cone contraction. Morally, both cases boil down to the study of suitable collections of 2 by 2 matrices and their contraction properties on the Riemann sphere.

Dubois, Loďc

2010-01-01T23:59:59.000Z

288

Olene Gap Geothermal Project | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth'sOklahoma/Geothermal < Oklahoma Jump to: navigation,Olene Gap Geothermal

289

Microscopic structure and energy transfer of vacancy-related defect pairs with Erbium in wide-gap semiconductors  

E-Print Network [OSTI]

/2 observed at 154 nm coincides with the minimum absorption of typical silica-based optical fibers. Since b Center for Optical Technologies, Lehigh University, Bethlehem, PA 18015, USA c Department words, low-energy irradiation seems to be a promising way to enhance the Er-luminescence desired

Schmidt, Wolf Gero

290

Mott Insulator-Superfluid Transition in a Generalized Bose-Hubbard Model with Topologically Non-trivial Flat-Band  

E-Print Network [OSTI]

In this paper, we studied a generalized Bose-Hubbard model on a checkerboard lattice with topologically nontrivial flat-band. We used mean-field method to decouple the model Hamiltonian and obtained phase diagram by Landau theory of second-order phase transition. We further calculate the energy gap and the dispersion of quasi-particle or quasi-hole in Mott insulator state and found that in strong interaction limit the quasi-particles or the quasi-holes also have flat bands.

Xing-Hai Zhang; Su-Peng Kou

2012-05-30T23:59:59.000Z

291

Apparatus for loading a band saw blade  

DOE Patents [OSTI]

A band saw blade is loaded between pairs of guide wheels upon tensioning the blade by guiding the blade between pairs of spaced guide plates which define converging slots that converge toward the guide wheels. The approach is particularly useful in loading blades on underwater band saw machines used to cut radioactive materials. 2 figs.

Reeves, S.R.

1990-03-20T23:59:59.000Z

292

Quasiparticle self-consistent GW calculations for PbS, PbSe, and PbTe: Band structure and pressure coefficients  

E-Print Network [OSTI]

and in solar-energy panels.8 With Tl doping PbTe may even exhibit superconductivity.9,10 The lead chalcogenides of states. The pressure-induced gap closure leads to linear Dirac-type band dispersions around the L point states being interchanged.19,25 These states have the same L6 symmetry but different parity and orbital

Svane, Axel Torstein

293

Photodiode characteristics and band alignment parameters of epitaxial Al{sub 0.5}Ga{sub 0.5}P  

SciTech Connect (OSTI)

Wide-bandgap semiconductor Al{sub x}Ga{sub 1-x}P is a promising material candidate for low-noise photodiodes in blue/UV spectrum. Photodiodes were fabricated on Al{sub 0.5}Ga{sub 0.5}P epitaxial layer grown lattice matched on GaP substrate by molecular beam epitaxy. Although quantum efficiency is low for standard p-i-n photodiode due to inadvertent photon absorption in the top p-layer, it can be significantly improved by opening a recessed window in the top p-layer or by using a Schottky junction photodiode structure. Al{sub 0.5}Ga{sub 0.5}P band alignment parameters can be extrapolated from the current-voltage characteristics of Al{sub 0.5}Ga{sub 0.5}P Schottky junctions. The bandgap of Al{sub 0.5}Ga{sub 0.5}P was measured to be 2.38 eV.

Chen An [Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511 (United States); Woodall, Jerry M. [School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

2009-01-12T23:59:59.000Z

294

Next Generation Nuclear Plant GAP Analysis Report  

SciTech Connect (OSTI)

As a follow-up to the phenomena identification and ranking table (PIRT) studies conducted recently by NRC on next generation nuclear plant (NGNP) safety, a study was conducted to identify the significant 'gaps' between what is needed and what is already available to adequately assess NGNP safety characteristics. The PIRT studies focused on identifying important phenomena affecting NGNP plant behavior, while the gap study gives more attention to off-normal behavior, uncertainties, and event probabilities under both normal operation and postulated accident conditions. Hence, this process also involved incorporating more detailed evaluations of accident sequences and risk assessments. This study considers thermal-fluid and neutronic behavior under both normal and postulated accident conditions, fission product transport (FPT), high-temperature metals, and graphite behavior and their effects on safety. In addition, safety issues related to coupling process heat (hydrogen production) systems to the reactor are addressed, given the limited design information currently available. Recommendations for further study, including analytical methods development and experimental needs, are presented as appropriate in each of these areas.

Ball, Sydney J [ORNL; Burchell, Timothy D [ORNL; Corwin, William R [ORNL; Fisher, Stephen Eugene [ORNL; Forsberg, Charles W. [Massachusetts Institute of Technology (MIT); Morris, Robert Noel [ORNL; Moses, David Lewis [ORNL

2008-12-01T23:59:59.000Z

295

Quantum confinement in GaP nanoclusters  

SciTech Connect (OSTI)

We have prepared GaP and GaAs nanoclusters from organometallic condensation reactions of E[Si(ChH{sub 3})3]3 (E = P, As) and GaCl{sub 3}. The size of the as synthesized clusters is 10 {Angstrom} to 15 {Angstrom}. Larger clusters of 20 {Angstrom} to 30 {Angstrom} size were obtained by thermal annealing of the as grown material. X-ray diffraction and transmission electron microscopy confirm the high crystalline quality. A lattice contraction of 6.7% could be seen for 10 {Angstrom} sized GaAs clusters. The clusters are nearly spherical in shape. Optical absorption spectra show a distinct line which can be assigned to the fundamental transition of the quantum confined electronic state. The measured blue shift, with respect to the GaP bulk absorption edge is 0.53 eV. As the cluster is smaller than the exciton radius, we can calculate the cluster size from this blue shift and obtain 20.2 {Angstrom}, consistent with the results from X-ray diffraction of 19.5 {Angstrom} for the same sample.

Laurich, B.K.; Smith, D.C.; Healy, M.D.

1994-06-01T23:59:59.000Z

296

Extended Supersymmetry in Gapped and Superconducting Graphene  

E-Print Network [OSTI]

In view of the many quantum field theoretical descriptions of graphene in $2+1$ dimensions, we present another field theoretical feature of graphene, in the presence of defects. Particularly, we shall be interested in gapped graphene in the presence of a domain wall and also for superconducting graphene in the presence of a vortex. As we explicitly demonstrate, the gapped graphene electrons that are localized on the domain wall are associated with four $N=2$ one dimensional supersymmetries, with each pair combining to form an extended $N=4$ supersymmetry with non-trivial topological charges. The case of superconducting graphene is more involved, with the electrons localized on the vortex being associated with $n$ one dimensional supersymmetries, which in turn combine to form an $N=2n$ extended supersymmetry with no-trivial topological charges. As we shall prove, all supersymmetries are unbroken, a feature closely related to the number of the localized fermions and also to the exact form of the associated oper...

Oikonomou, V K

2014-01-01T23:59:59.000Z

297

Extended Supersymmetry in Gapped and Superconducting Graphene  

E-Print Network [OSTI]

In view of the many quantum field theoretical descriptions of graphene in $2+1$ dimensions, we present another field theoretical feature of graphene, in the presence of defects. Particularly, we shall be interested in gapped graphene in the presence of a domain wall and also for superconducting graphene in the presence of a vortex. As we explicitly demonstrate, the gapped graphene electrons that are localized on the domain wall are associated with four $N=2$ one dimensional supersymmetries, with each pair combining to form an extended $N=4$ supersymmetry with non-trivial topological charges. The case of superconducting graphene is more involved, with the electrons localized on the vortex being associated with $n$ one dimensional supersymmetries, which in turn combine to form an $N=2n$ extended supersymmetry with no-trivial topological charges. As we shall prove, all supersymmetries are unbroken, a feature closely related to the number of the localized fermions and also to the exact form of the associated operators. In addition, the corresponding Witten index is invariant under compact and odd perturbations.

V. K. Oikonomou

2014-11-30T23:59:59.000Z

298

FORMATION AND SURVIVABILITY OF GIANT PLANETS ON WIDE ORBITS  

SciTech Connect (OSTI)

Motivated by the recent discovery of massive planets on wide orbits, we present a mechanism for the formation of such planets via disk fragmentation in the embedded phase of star formation. In this phase, the forming disk intensively accretes matter from the natal cloud core and undergoes several fragmentation episodes. However, most fragments are either destroyed or driven into the innermost regions (and probably onto the star) due to angular momentum exchange with spiral arms, leading to multiple FU-Ori-like bursts and disk expansion. Fragments that are sufficiently massive and form in the late embedded phase (when the disk conditions are less extreme) may open a gap and evolve into giant planets on typical orbits of several tens to several hundreds of AU. For this mechanism to work, the natal cloud core must have sufficient mass and angular momentum to trigger the burst mode and also form extended disks of the order of several hundreds of AU. When mass loading from the natal cloud core diminishes and the main fragmentation phase ends, such extended disks undergo a transient episode of contraction and density increase, during which they may give birth to a last and survivable set of giant planets on wide and relatively stable orbits.

Vorobyov, Eduard I. [Institute for Computational Astrophysics, Saint Mary's University, Halifax, NS B3H 3C3 (Canada); Basu, Shantanu, E-mail: vorobyov@ap.smu.c, E-mail: basu@astro.uwo.c [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada)

2010-05-01T23:59:59.000Z

299

Modelling of monovacancy diffusion in W over wide temperature range  

SciTech Connect (OSTI)

The diffusion of monovacancies in tungsten is studied computationally over a wide temperature range from 1300?K until the melting point of the material. Our modelling is based on Molecular Dynamics technique and Density Functional Theory. The monovacancy migration barriers are calculated using nudged elastic band method for nearest and next-nearest neighbour monovacancy jumps. The diffusion pre-exponential factor for monovacancy diffusion is found to be two to three orders of magnitude higher than commonly used in computational studies, resulting in attempt frequency of the order 10{sup 15} Hz. Multiple nearest neighbour jumps of monovacancy are found to play an important role in the contribution to the total diffusion coefficient, especially at temperatures above 2/3 of T{sub m}, resulting in an upward curvature of the Arrhenius diagram. The probabilities for different nearest neighbour jumps for monovacancy in W are calculated at different temperatures.

Bukonte, L., E-mail: laura.bukonte@helsinki.fi; Ahlgren, T.; Heinola, K. [Department of Physics, University of Helsinki, P.O. Box 43, 00014 Helsinki (Finland)

2014-03-28T23:59:59.000Z

300

Photodiode characteristics and band alignment parameters of epitaxial Al0.5Ga0.5P  

E-Print Network [OSTI]

Photodiode characteristics and band alignment parameters of epitaxial Al0.5Ga0.5P An Chen1,a-bandgap semiconductor AlxGa1-xP is a promising material candidate for low-noise photodiodes in blue/UV spectrum. Photodiodes were fabricated on Al0.5Ga0.5P epitaxial layer grown lattice matched on GaP substrate by molecular

Woodall, Jerry M.

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


301

Arc voltage distribution skewness as an indicator of electrode gap during vacuum arc remelting  

DOE Patents [OSTI]

The electrode gap of a VAR is monitored by determining the skewness of a distribution of gap voltage measurements. A decrease in skewness indicates an increase in gap and may be used to control the gap.

Williamson, Rodney L. (Albuquerque, NM); Zanner, Frank J. (Sandia Park, NM); Grose, Stephen M. (Glenwood, WV)

1998-01-01T23:59:59.000Z

302

Arc voltage distribution skewness as an indicator of electrode gap during vacuum arc remelting  

DOE Patents [OSTI]

The electrode gap of a VAR is monitored by determining the skewness of a distribution of gap voltage measurements. A decrease in skewness indicates an increase in gap and may be used to control the gap. 4 figs.

Williamson, R.L.; Zanner, F.J.; Grose, S.M.

1998-01-13T23:59:59.000Z

303

DFAS Wide-Area Workflow Issues  

Broader source: Energy.gov [DOE]

Presentation covers the DFAS wide-area workflow issues and is given at the Spring 2011 Federal Utility Partnership Working Group (FUPWG) meeting.

304

PHYSICAL REVIEW B 84, 035315 (2011) Theoretical analysis of the crystal structure, band-gap energy, polarization, and piezoelectric  

E-Print Network [OSTI]

have already been incorporated in flat panel displays and solar cells as transparent electrodesO can be tailored by alloying ZnO with BeO for applications such as electrodes in flat panel displays and solar cells, blue and ultraviolet (UV) light emitting devices, and highly sensitive UV detectors. We

Alpay, S. Pamir

2011-01-01T23:59:59.000Z

305

PHYSICAL REVIEW B 84, 245206 (2011) First-principles study of band gap engineering via oxygen vacancy doping  

E-Print Network [OSTI]

formulate guidelines that can be used to predict the location of oxygen vacancies in perovskite solid transport of O2- ions through the oxide electrolyte membrane over a range of temperatures. In solar energy several chemical compositions and different cation arrangements for the two Zr-modified solid solutions

Rappe, Andrew M.

306

Exploring Visible-Light-Responsive Photocatalysts for Water Splitting Based on Novel Band-gap Engineering Strategies  

E-Print Network [OSTI]

Chapter 4 Boron Carbides as Efficient, Metal-Free, Visible-and transition metals, the boron carbide products werex Chapter Boron Carbides as Efficient, Metal-free, Visible-

Liu, Jikai

2013-01-01T23:59:59.000Z

307

Propagation of Lamb waves in one-dimensional quasiperiodic composite thin plates: A split of phonon band gap  

E-Print Network [OSTI]

Propagation of Lamb waves in one-dimensional quasiperiodic composite thin plates: A split of phonon the propagation of Lamb waves in one-dimensional quasiperiodic composite thin plates made of tungsten B spectra, Raman scattering spectra, and propagating modes of acoustic waves on corrugated surfaces.14

Li, Baowen

308

Nature of the Band Gap and Origin of the Electro-/Photo-Activity of Co3O4.  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the Contributions andDataNational Library of1, 2007 (next release3,3,NatureNature|

309

Optical absorption and band gap reduction in (Fe1-xCrx)2O3 solid solutions:  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - September 2006 The 2002 WholesaleEnergy'sRunningOperationsDistribution,RainA

310

Rotational bands in odd-A Cm and Cf isotopes: Exploring the highest neutron orbitals  

SciTech Connect (OSTI)

Rotational bands have been identified up to high spins ({approx_equal}28({h_bar}/2{pi})) in the odd-A nuclei {sup 247,249}Cm and {sup 249}Cf through inelastic excitation and transfer reactions around the Z=100 region where stability results from shell effects. The [620]1/2 Nilsson configuration in {sup 249}Cm is the highest-lying neutron orbital, from above the N=164 spherical subshell gap, for which high-spin rotational behavior has been established. The data allow for an unambiguous experimental assignment of configurations to the observed bands, unusual for odd-A nuclei near Z=100. The high-spin properties are described in terms of Woods-Saxon cranking calculations.

Tandel, S. K.; Chowdhury, P.; Lakshmi, S.; Tandel, U. S. [Department of Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854 (United States); Ahmad, I.; Carpenter, M. P.; Gros, S.; Janssens, R. V. F.; Khoo, T. L.; Kondev, F. G.; Greene, J. P.; Lauritsen, T.; Lister, C. J.; Peterson, D.; Robinson, A.; Seweryniak, D.; Zhu, S. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Hartley, D. J. [Department of Physics, US Naval Academy, Annapolis, Maryland 21402 (United States)

2010-10-15T23:59:59.000Z

311

Maximum Likelihood Sub-band Weighting for Robust Speech Recognition  

E-Print Network [OSTI]

, bins of log filter-band energy (FBE) in each sub-band are multiplied with a weighting factor depending on the reliability of the sub-band. For each sub-band, zero padding is performed on the log FBE vector lengthening. For the DCT has the size of full-band FBE vector, the feature vector consists of the correlations across

312

Sensitivity Analysis of the Gap Heat Transfer Model in BISON.  

SciTech Connect (OSTI)

This report summarizes the result of a NEAMS project focused on sensitivity analysis of the heat transfer model in the gap between the fuel rod and the cladding used in the BISON fuel performance code of Idaho National Laboratory. Using the gap heat transfer models in BISON, the sensitivity of the modeling parameters and the associated responses is investigated. The study results in a quantitative assessment of the role of various parameters in the analysis of gap heat transfer in nuclear fuel.

Swiler, Laura Painton; Schmidt, Rodney C.; Williamson, Richard (INL); Perez, Danielle (INL)

2014-10-01T23:59:59.000Z

313

Rotational band properties in {sup 165}Er  

SciTech Connect (OSTI)

High-spin states in {sup 165}Er have been studied experimentally using the {sup 160}Gd({sup 9}Be, 4n) reaction at beam energies of 42 and 45 MeV. The previously known bands based on the 5/2{sup +}[642], 5/2{sup -}[523], and 11/2{sup -}[505] configurations are extended to (49/2{sup +}), (45/2{sup -}), and (31/2{sup -}) states, respectively. The rotational bands in {sup 165}Er generally show gradual alignment processes, indicating strong band interactions associated with the i{sub 13/2} neutron alignments. The band properties are compared with those in the neighboring nuclei and discussed within the framework of the cranked shell model.

Wang, S. T. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Zhou, X. H.; Zhang, Y. H.; Zheng, Y.; Liu, M. L.; Chen, L.; Zhang, N. T.; Hua, W.; Guo, S.; Qiang, Y. H.; Li, G. S.; Ding, B. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Shi, Y.; Xu, F. R. [School of Physics, and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)

2011-07-15T23:59:59.000Z

314

Catalysis by Design: Bridging the Gap Between Theory and Experiments...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Between Theory and Experiments at Nanoscale Level Catalysis by Design: Bridging the Gap Between Theory and Experiments at Nanoscale Level Studies on a simple platinum-alumina...

315

Catalysis by Design: Bridging the Gap between Theory and Experiments...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

between Theory and Experiments Catalysis by Design: Bridging the Gap between Theory and Experiments Poster presentation at the 2007 Diesel Engine-Efficiency & Emissions Research...

316

FAQS Gap Analysis Qualification Card – Fire Protection Engineering  

Broader source: Energy.gov [DOE]

Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

317

FAQS Gap Analysis Qualification Card – Nuclear Explosive Safety Study  

Broader source: Energy.gov [DOE]

Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

318

Dipole Bands in {sup 196}Hg  

SciTech Connect (OSTI)

High spin states in {sup 196}Hg have been populated in the {sup 198}Pt({alpha},6n) reaction at 65 MeV and the level scheme has been extended. A new dipole band has been observed and a previously observed dipole has been confirmed. Excitation energies, spins and parities of these bands were determined from DCO ratio and linear polarization measurements. Possible quasiparticle excitations responsible for these structures are discussed.

Lawrie, J. J.; Lawrie, E. A.; Newman, R. T.; Sharpey-Schafer, J. F.; Smit, F. D. [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Msezane, B. [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Physics Department, University of Zululand, Private Bag X1001, Kwadlangezwa 3886 (South Africa); Benatar, M.; Mabala, G. K.; Mutshena, K. P. [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Physics Department, University of Cape Town, Rondebosch 7700 (South Africa); Federke, M.; Mullins, S. M. [Physics Department, University of Cape Town, Rondebosch 7700 (South Africa); Ncapayi, N. J.; Vymers, P. [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Physics Department, University of the Western Cape, Private Bag X17, Belleville 7535 (South Africa)

2011-10-28T23:59:59.000Z

319

Control Banding and Nanotechnology Synergist  

SciTech Connect (OSTI)

The average Industrial Hygienist (IH) loves a challenge, right? Okay, well here is one with more than a few twists. We start by going through the basics of a risk assessment. You have some chemical agents, a few workers, and the makings of your basic exposure characterization. However, you have no occupational exposure limit (OEL), essentially no toxicological basis, and no epidemiology. Now the real handicap is that you cannot use sampling pumps, cassettes, tubes, or any of the media in your toolbox, and the whole concept of mass-to-dose is out the window, even at high exposure levels. Of course, by the title, you knew we were talking about nanomaterials (NM). However, we wonder how many IHs know that this topic takes everything you know about your profession and turns it upside down. It takes the very foundations that you worked so hard in college and in the field to master and pulls it out from underneath you. It even takes the gold standard of our profession, the quantitative science of exposure assessment, and makes it look pretty darn rusty. Now with NM there is the potential to get some aspect of quantitative measurements, but the instruments are generally very expensive and getting an appropriate workplace personal exposure measurement can be very difficult if not impossible. The potential for workers getting exposures, however, is very real, as evidenced by a recent publication reporting worker exposures to polyacrylate nanoparticles in a Chinese factory (Song et al. 2009). With something this complex and challenging, how does a concept as simple as Control Banding (CB) save the day? Although many IHs have heard of CB, most of their knowledge comes from its application in the COSHH Essentials toolkit. While there is conflicting published research on COSHH Essentials and its value for risk assessments, almost all of the experts agree that it can be useful when no OELs are available (Zalk and Nelson 2008). It is this aspect of CB, its utility with uncertainty, that attracted international NM experts to recommend this qualitative risk assessment approach for NM. However, since their CB recommendation was only in theory, we took on the challenge of developing a working toolkit, the CB Nanotool (see Zalk et al. 2009 and Paik et al. 2008), as a means to perform a risk assessment and protect researchers at the Lawrence Livermore National Laboratory. While it's been acknowledged that engineered NM have potentially endless benefits for society, it became clear to us that the very properties that make nanotechnology so useful to industry could also make them dangerous to humans and the environment. Among the uncertainties and unknowns with NM are: the contribution of their physical structure to their toxicity, significant differences in their deposition and clearance in the lungs when compared to their parent material (PM), a lack of agreement on the appropriate indices for exposure to NM, and very little background information on exposure scenarios or populations at risk. Part of this lack of background information can be traced to the lack of risk assessments historically performed in the industry, with a recent survey indicating that 65% of companies working with NM are not doing any kind of NM-specific risk assessment as they focus on traditional PM methods for IH (Helland et al. 2009). The good news is that the amount of peer-reviewed publications that address environmental, health and safety aspects of NM has been increasing over the last few years; however, the percentage of these that address practical methods to reduce exposure and protect workers is orders of magnitude lower. Our intent in developing the CB Nanotool was to create a simplified approach that would protect workers while unraveling the mysteries of NM for experts and non-experts alike. Since such a large part of the toxicological effects of both the physical and chemical properties of NM were unknown, not to mention changing logarithmically as new NM research continues growing, we needed to account for this lack of information as part of the CB Nano

Zalk, D; Paik, S

2009-12-15T23:59:59.000Z

320

Band structure engineering of anatase TiO{sub 2} by metal-assisted P-O coupling  

SciTech Connect (OSTI)

In this work, we demonstrate that the metal-assisted P-O coupling is an effective approach to improve the photoelectrochemical properties of TiO{sub 2}. The (Sc + P) and (In + P) codoping effects on electronic structures and photocatalytic activities of anatase TiO{sub 2} are examined by performing hybrid density functional theory calculations. It is found that the coupling of P dopant with the second-nearest neighboring O atom assisted by acceptor metals (Sc/In) leads to the fully occupied and delocalized intermediate bands within the band gap of anatase TiO{sub 2}, which is driven by the P-O antibonding states (?*). This metal-assisted P-O coupling can prevent the recombination of photogenerated electron-hole pairs and effectively reduce the band gap of TiO{sub 2}. Moreover, the band edge alignments in (Sc + P) and (In + P) codoped anatase TiO{sub 2} are desirable for water-splitting. The calculated optical absorption curves indicate that (Sc + P) and (In + P) codoping in anatase TiO{sub 2} can also effectively enhance the visible light absorption.

Wang, Jiajun; Meng, Qiangqiang [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China)] [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Huang, Jing [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China) [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); School of Materials and Chemical Engineering, Anhui Jianzhu University, Hefei, Anhui 230601 (China); Li, Qunxiang, E-mail: liqun@ustc.edu.cn; Yang, Jinlong [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China) [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2014-05-07T23:59:59.000Z

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


321

Behavioral/Systems/Cognitive Synchronous, Focally Modulated -Band Oscillations  

E-Print Network [OSTI]

, primarily synchronous -band voltage oscillations occur in the sensorimotor and frontal cortex of humansBehavioral/Systems/Cognitive Synchronous, Focally Modulated -Band Oscillations Characterize Local oscillations in the -frequency band ( 15­30Hz

Graybiel, Ann M.

322

High Field W-Band (95 GHz) EPR | EMSL  

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

High Field W-Band (95 GHz) EPR High Field W-Band (95 GHz) EPR The W-band pulsed EPR spectrometer, introduced in 2011, is one of only two of its design worldwide. It uses a...

323

ISM band to U-NII band frequency transverter and method of frequency transversion  

DOE Patents [OSTI]

A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz-6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.

Stepp, Jeffrey David (Grandview, MO); Hensley, Dale (Grandview, MO)

2006-04-04T23:59:59.000Z

324

Engineering integrated pure narrow-band photon sources  

E-Print Network [OSTI]

Engineering and controlling well defined states of light for quantum information applications is of increasing importance as the complexity of quantum systems grows. For example, in quantum networks high multi-photon interference visibility requires properly devised single mode sources. In this paper we propose a spontaneous parametric down conversion source based on an integrated cavity-waveguide, where single narrow-band, possibly distinct, spectral modes for the idler and the signal fields can be generated. This mode selection takes advantage of the clustering effect, due to the intrinsic dispersion of the nonlinear material. In combination with a CW laser and fast detection, our approach provides a means to engineer a source that can efficiently generate pure photons, without filtering, that is compatible with long distance quantum communication. Furthermore, it is extremely flexible and could easily be adapted to a wide variety of wavelengths and applications.

Enrico Pomarico; Bruno Sanguinetti; Clara I. Osorio; Harald Herrmann; Rob Thew

2011-08-29T23:59:59.000Z

325

NOVEMBER 2003 2705J O R G E N S E N E T A L . Variations Associated with Cores and Gaps of a Pacific Narrow Cold Frontal Rainband  

E-Print Network [OSTI]

Experiment. Airborne Doppler radar data obtained while the frontal system was well offshore indicated ends of the cores and just north of the gaps, the wind shear weakened with less intense updrafts that tilted upshear and contained a broader band of rainfall. Simulations using the nonhydrostatic nested grid

Pu, Zhaoxia

326

ERDC/CERLTR-05-38 Determining Research Gaps  

E-Print Network [OSTI]

ERDC/CERLTR-05-38 Determining Research Gaps in Disturbance Data for Fort Bliss and a Conceptual-38 November 2005 Determining Research Gaps in Disturbance Data for Fort Bliss and a Conceptual Model Tamara Bliss #12;ABSTRACT Numerous research and outside monitoring efforts have been completed for Fort Bliss

Fehmi, Jeffrey S.

327

Anisotropic Energy Gaps of Iron-Based Superconductivity from Intraband Quasiparticle Interference in LiFeAs  

SciTech Connect (OSTI)

If strong electron-electron interactions between neighboring Fe atoms mediate the Cooper pairing in iron-pnictide superconductors, then specific and distinct anisotropic superconducting energy gaps {Delta}{sub i}(k) should appear on the different electronic bands i. Here, we introduce intraband Bogoliubov quasiparticle scattering interference (QPI) techniques for determination of {Delta}{sub i}(k) in such materials, focusing on lithium iron arsenide (LiFeAs). We identify the three hole-like bands assigned previously as {gamma}, {alpha}{sub 2}, and {alpha}{sub 1}, and we determine the anisotropy, magnitude, and relative orientations of their {Delta}{sub i}(k). These measurements will advance quantitative theoretical analysis of the mechanism of Cooper pairing in iron-based superconductivity.

Davis J. C.; Allan, M.P.; Rost, A.W.; Mackenzie, A.P.; Xie, Y.; Kihou, K.; Lee, C.H.; Iyo, A.; Eisaki, H.; Chuang, T.-M.

2012-05-04T23:59:59.000Z

328

Criteria for shear banding in time-dependent flows of complex fluids  

E-Print Network [OSTI]

Within a highly generalised theoretical framework for the flow properties of complex fluids, we study the onset of shear banding in the three most common time-dependent experimental protocols: step stress, step strain and shear startup. By means of a linear stability analysis we derive a fluid-universal criterion for the onset of banding, separately for each protocol, that depends only on the shape of the experimentally measured time-dependent rheological response function, independent of the constitutive law and internal state variables of the particular fluid in question. Our predictions thus have the same status, in these time-dependent flows, as the widely known criterion for banding in steady state (of negatively sloping shear stress vs. shear rate). We support them with simulations of the rolie-poly model of polymeric fluids, the soft glassy rheology model, and a fluidity model.

Robyn L. Moorcroft; Suzanne M. Fielding

2013-01-21T23:59:59.000Z

329

West Wide Programmatic Environmental Impact Statement Record...  

Open Energy Info (EERE)

OpenEI Reference LibraryAdd to library Legal Document- OtherOther: West Wide Programmatic Environmental Impact Statement Record of Decision (BLM)Legal Published NA Year Signed or...

330

GWIDD: Genome-wide protein docking database  

E-Print Network [OSTI]

Structural information on interacting proteins is important for understanding life processes at the molecular level. Genome-wide docking database is an integrated resource for structural studies of protein–protein interactions on the genome scale...

Kundrotas, Petras J.; Zhu, Zhengwei; Vasker, Ilya A.

2009-11-09T23:59:59.000Z

331

Ultra-wide bandwidth piezoelectric energy harvesting  

E-Print Network [OSTI]

Here, we present an ultra wide-bandwidth energy harvester by exploiting the nonlinear stiffness of a doubly clamped microelectromechanical systems (MEMSs) resonator. The stretching strain in a doubly clamped beam shows a ...

Hajati, Arman

332

Preprint August 2008: to appear in Neural Computation 1 Wide-band information transmission at the calyx of Held  

E-Print Network [OSTI]

at the calyx of Held Zhijun Yang1 , Matthias H. Hennig2 , Michael Postlethwaite3 , Ian D. Forsythe4 and Bruce P Abstract We use a mathematical model of the calyx of Held to explore information transmission at this giant words: short-term synaptic plasticity; signal transmission; mutual information; calyx of Held 1

Edinburgh, University of

333

Energy harvesting of random wide-band vibrations with applications to an electro-magnetic rotational energy harvester  

E-Print Network [OSTI]

In general, vibration energy harvesting is the scavenging of ambient vibration by transduction of mechanical kinetic energy into electrical energy. Many mechanical or electro-mechanical systems produce mechanical vibrations. ...

Trimble, A. Zachary

2011-01-01T23:59:59.000Z

334

Design of a Wide Bandwidth Phase Modulator and Modeling of Polar Transmitters with Split-band Envelope Modulation  

E-Print Network [OSTI]

synthesizer and direct-conversion architecture,” Solid-Stateband (850/900/1800/1900 MHz) direct conversion GSM/GPRS RFHence a direct digital to phase conversion occurs which is

Hameed, Sameed

2013-01-01T23:59:59.000Z

335

Integrated, Multi-Scale Characterization of Imbibition and Wettability Phenomena Using Magnetic Resonance and Wide-Band Dielectric Measurements  

SciTech Connect (OSTI)

The petrophysical properties of rocks, particularly their relative permeability and wettability, strongly influence the efficiency and the time-scale of all hydrocarbon recovery processes. However, the quantitative relationships needed to account for the influence of wettability and pore structure on multi-phase flow are not yet available, largely due to the complexity of the phenomena controlling wettability and the difficulty of characterizing rock properties at the relevant length scales. This project brings together several advanced technologies to characterize pore structure and wettability. Grain-scale models are developed that help to better interpret the electric and dielectric response of rocks. These studies allow the computation of realistic configurations of two immiscible fluids as a function of wettability and geologic characteristics. These fluid configurations form a basis for predicting and explaining macroscopic behavior, including the relationship between relative permeability, wettability and laboratory and wireline log measurements of NMR and dielectric response. Dielectric and NMR measurements have been made show that the response of the rocks depends on the wetting and flow properties of the rock. The theoretical models can be used for a better interpretation and inversion of standard well logs to obtain accurate and reliable estimates of fluid saturation and of their producibility. The ultimate benefit of this combined theoretical/empirical approach for reservoir characterization is that rather than reproducing the behavior of any particular sample or set of samples, it can explain and predict trends in behavior that can be applied at a range of length scales, including correlation with wireline logs, seismic, and geologic units and strata. This approach can substantially enhance wireline log interpretation for reservoir characterization and provide better descriptions, at several scales, of crucial reservoir flow properties that govern oil recovery.

Mukul M. Sharma; Steven L. Bryant; Carlos Torres-Verdin; George Hirasaki

2007-09-30T23:59:59.000Z

336

Generalized parton distributions and rapidity gap survival in exclusive diffractive pp scattering  

SciTech Connect (OSTI)

We propose a new approach to the problem of rapidity gap survival (RGS) in the production of high-mass systems (H = dijet, heavy quarkonium, Higgs boson) in double-gap exclusive diffractive pp scattering, pp-->p + (gap) + H + (gap) + p. It is based on the idea that hard and soft interactions proceed over widely different time- and distance scales and are thus approximately independent. The high-mass system is produced in a hard scattering process with exchange of two gluons between the protons. Its amplitude is calculable in terms of the gluon generalized parton distributions (GPDs) in the protons, which can be measured in J= production in exclusive ep scattering. The hard scattering process is modified by soft spectator interactions, which we calculate in a model-independent way in terms of the pp elastic scattering amplitude. Contributions from inelastic intermediate states are suppressed. A simple geometric picture of the interplay of hard and soft interactions in diffraction is obtained. The onset of the black-disk limit in pp scattering at TeV energies strongly suppresses diffraction at small impact parameters and is the main factor in determining the RGS probability. Correlations between hard and soft interactions (e.g. due to scattering from the long-range pion field of the proton, or due to possible short-range transverse correlations between partons) further decrease the RGS probability. We also investigate the dependence of the diffractive cross section on the transverse momenta of the final-state protons (''diffraction pattern''). By measuring this dependence one can perform detailed tests of the interplay of hard and soft interactions, and even extract information about the gluon GPD in the proton. Such studies appear to be feasible with the planned forward detectors at the LHC.

Leonid Frankfurt; Charles Hyde-Wright; Mark Strikman; Christian Weiss

2007-03-01T23:59:59.000Z

337

System-level, Unified In-band and Out-of-band Dynamic Thermal Control  

E-Print Network [OSTI]

of the decrease in computation capacity. Less studied are out-of-band techniques (e.g. CPU cooling fans [10]) that operate completely outside the critical performance path of an application. Out-of-band techniques cool system slowdowns or shutdowns. Techniques such as dynamically scaling down the voltage of the CPUs

338

Energy Band Model Based on Effective Mass  

E-Print Network [OSTI]

In this work, we demonstrate an alternative method of deriving an isotropic energy band model using a one-dimensional definition of the effective mass and experimentally observed dependence of mass on energy. We extend the effective mass definition to anti-particles and particles with zero rest mass. We assume an often observed linear dependence of mass on energy and derive a generalized non-parabolic energy-momentum relation. The resulting non-parabolicity leads to velocity saturation at high particle energies. We apply the energy band model to free relativistic particles and carriers in solid state materials and obtain commonly used dispersion relations and experimentally confirmed effective masses. We apply the model to zero rest mass particles in graphene and propose using the effective mass for photons. Therefore, it appears that the new energy band model based on the effective mass can be applied to relativistic particles and carriers in solid state materials.

Viktor Ariel

2012-09-06T23:59:59.000Z

339

Band filling effects on temperature performance of intermediate band quantum wire solar cells  

SciTech Connect (OSTI)

Detailed studies of solar cell efficiency as a function of temperature were performed for quantum wire intermediate band solar cells grown on the (311)A plane. A remotely doped one-dimensional intermediate band made of self-assembled In{sub 0.4}Ga{sub 0.6}As quantum wires was compared to an undoped intermediate band and a reference p-i-n GaAs sample. These studies indicate that the efficiencies of these solar cells depend on the population of the one-dimensional band by equilibrium free carriers. A change in this population by free electrons under various temperatures affects absorption and carrier transport of non-equilibrium carriers generated by incident light. This results in different efficiencies for both the doped and undoped intermediate band solar cells in comparison with the reference GaAs p-i-n solar cell device.

Kunets, Vas. P., E-mail: vkunets@uark.edu; Furrow, C. S.; Ware, M. E.; Souza, L. D. de; Benamara, M.; Salamo, G. J. [Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Mortazavi, M. [Department of Chemistry and Physics, University of Arkansas at Pine Bluff, Pine Bluff, Arkansas 71601 (United States)

2014-08-28T23:59:59.000Z

340

UNIDENTIFIED INFRARED EMISSION BANDS: PAHs or MAONs?  

SciTech Connect (OSTI)

We suggest that the carrier of the unidentified infrared emission (UIE) bands is an amorphous carbonaceous solid with mixed aromatic/aliphatic structures, rather than free-flying polycyclic aromatic hydrocarbon molecules. Through spectral fittings of the astronomical spectra of the UIE bands, we show that a significant amount of the energy is emitted by the aliphatic component, implying that aliphatic groups are an essential part of the chemical structure. Arguments in favor of an amorphous, solid-state structure rather than a gas-phase molecule as a carrier of the UIE are also presented.

Sun Kwok; Yong Zhang, E-mail: sunkwok@hku.hk [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (Hong Kong)

2013-07-01T23:59:59.000Z

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


341

British Academy (e-GAP2) Guide for Applicants The British Academy e-GAP2 applicant guide July 2012 Page 1  

E-Print Network [OSTI]

British Academy (e-GAP2) Guide for Applicants The British Academy e-GAP2 applicant guide July 2012 Page 1 2012 INTERNAL USER GUIDE A Guide to the British Academy Electronic Submission System (e-GAP2) A Quick Guide for Applicants applying for funding using the e-GAP2 System The British Academy web page

342

Pairing Gaps, Pseudogaps, and Phase Diagrams for Cuprate Superconductors  

E-Print Network [OSTI]

We use a symmetry-constrained variational procedure to construct a generalization of BCS to include Cooper pairs with non-zero momentum and angular momentum. The resulting gap equations are solved at zero and finite temperature, and the doping-dependent solutions are used to construct gap and phase diagrams. We find a pseudogap terminating at a critical doping that may be interpreted in terms of both competing order and preformed pairs. The strong similarity between observation and predicted gap and phase structure suggests that this approach may provide a unified description of the complex structure observed for cuprate superconductors.

Yang Sun; Mike Guidry; Cheng-Li Wu

2007-02-21T23:59:59.000Z

343

Shear banding in soft glassy materials  

E-Print Network [OSTI]

Many soft materials, including foams, dense emulsions, micro gel bead suspensions, star polymers, dense packing of surfactant onion micelles, and textured morphologies of liquid crystals, share the basic "glassy" features of structural disorder and metastability. These in turn give rise to several notable features in the low frequency shear rheology (deformation and flow properties) of these materials: in particular, the existence of a yield stress below which the material behaves like a solid, and above which it flows like a liquid. In the last decade, intense experimental activity has also revealed that these materials often display a phenomenon known as shear banding, in which the flow profile across the shear cell exhibits macroscopic bands of different viscosity. Two distinct classes of yield stress fluid have been identified: those in which the shear bands apparently persist permanently (for as long as the flow remains applied), and those in which banding arises only transiently during a process in which a steady flowing state is established out of an initial rest state (for example, in a shear startup or step stress experiment). After surveying the motivating experimental data, we describe recent progress in addressing it theoretically, using the soft glassy rheology model and a simple fluidity model. We also briefly place these theoretical approaches in the context of others in the literature, including elasto-plastic models, shear transformation zone theories, and molecular dynamics simulations. We discuss finally some challenges that remain open to theory and experiment alike.

Suzanne M. Fielding

2014-08-20T23:59:59.000Z

344

X-Band Photoinjector Beam Dynamics  

SciTech Connect (OSTI)

SLAC is studying the feasibility of using an X-band RF photocathode gun to produce low emittance bunches for applications such as a mono-energetic MeV {gamma} ray source (in collaboration with LLNL) and a photoinjector for a compact FEL. Beam dynamics studies are being done for a configuration consisting of a 5.5-cell X-band gun followed by several 53-cell high-gradient X-band accelerator structures. A fully 3D program, ImpactT, is used to track particles taking into account space charge forces, short-range longitudinal and transverse wakefields, and the 3D rf fields in the structures, including the quadrupole component of the couplers. The effect of misalignments of the various elements, including the drive-laser, gun, solenoid and accelerator structures, are evaluated. This paper presents these results and estimates of the expected bunch emittance vs cathode gradient, and the effects of mixing between the fundamental and off-frequency longitudinal modes. An X-band gun at SLAC has been shown to operate reliably with a 200 MV/m acceleration gradient at the cathode, which is nearly twice the 115 MV/m acceleration gradient in the LCLS gun. The higher gradient should roughly balance the space charge related transverse emittance growth for the same bunch charge but provide a 3-4 times shorter bunch length. The shorter length would make the subsequent bunch compression easier and allow for a more effective use of emittance exchange. Such a gun can also be used with an X-band linac to produce a compact FEL or g ray source that would require rf sources of only one frequency for beam generation and acceleration. The feasibility of using an X-band rf photocathode gun and accelerator structures to generate high quality electron beams for compact FELs and g ray sources is being studied at SLAC. Results from the X-band photoinjector beam dynamics studies are reported in this paper.

Zhou, Feng; /SLAC; Adolphsen, Chris; /SLAC; Ding, Yuantao; /SLAC; Li, Zenghai; /SLAC; Vlieks, Arnold; /SLAC

2011-12-13T23:59:59.000Z

345

Wide field imaging of distant clusters  

E-Print Network [OSTI]

Wide field imaging is key to understanding the build-up of distant clusters and their galaxy population. By focusing on the so far unexplored outskirts of clusters, where infalling galaxies first hit the cluster potential and the hot intracluster medium, we can help separate cosmological field galaxy evolution from that driven by environment. I present a selection of recent advancements in this area, with particular emphasis on Hubble Space Telescope wide field imaging, for its superior capability to deliver galaxy morphologies and precise shear maps of distant clusters.

T. Treu

2004-08-05T23:59:59.000Z

346

Effects of Out-of-Plane Disorder on the Nodal Quasiparticle and Superconducting Gap in Single-Layer Bi_2Sr_1.6Ln_0.4CuO_6 delta (Ln = La, Nd, Gd)  

SciTech Connect (OSTI)

How out-of-plane disorder affects the electronic structure has been investigated for the single-layer cuprates Bi{sub 2}Sr{sub 1.6}Ln{sub 0.4}CuO{sub 6+{delta}} (Ln = La, Nd, Gd) by angle-resolved photoemission spectroscopy. We have observed that, with increasing disorder, while the Fermi surface shape and band dispersions are not affected, the quasi-particle width increases, the anti-nodal gap is enhanced and the superconducting gap in the nodal region is depressed. The results indicate that the superconductivity is significantly depressed by out-of-plane disorder through the enhancement of the anti-nodal gap and the depression of the superconducting gap in the nodal region.

Hashimoto, M.

2011-01-04T23:59:59.000Z

347

Plugging of intersubassembly gaps by downward flowing molten steel. [LMFBR  

SciTech Connect (OSTI)

In the assessment of the meltout phase of an LMFBR hypothetical core disruptive accident, a pathway for the escape of molten fuel from the disrupted core is provided by the narrow channels separating adjacent subassemblies. However, the removal of fuel through intersubassembly gaps might be impeded by steel blockage formation, if molten steel is postulated to enter the gap network ahead of disrupted fuel. Reported here are the results of an analysis of the conduction freezing controlled penetration behavior of molten steel flowing downward through the voided (of sodium) gap channels nominally separating adjacent subassemblies below the active core region. The objective is to determine the range of conditions under which the steel is predicted to be deposited as a thin crust on the channel walls leaving an open pathway remaining for subsequent fuel flow instead of forming a complete plug which closes off the gap channel and obstructs fuel removal immediately thereafter.

Sienicki, J.J.; Spencer, B.W.

1984-01-01T23:59:59.000Z

348

Perspective The MAHB, the Culture Gap, and Some Really  

E-Print Network [OSTI]

is a product of population size, per capita consumption, and the sorts of technologies and social and economic systems that supply the consumption. A vast ``culture gap'' has developed over the past century or so

Ford, James

349

Air-gap sacrificial materials by initiated chemical vapor deposition  

E-Print Network [OSTI]

P(neopentyl methacrylate-co-ethylene glycol dimethacrylate) copolymer, abbreviated as P(npMAco-EGDA), was selected as the potential air-gap sacrificial material among possible combination of twenty monomers and four ...

Lee, Long Hua

2007-01-01T23:59:59.000Z

350

Permanent-magnet-less machine having an enclosed air gap  

DOE Patents [OSTI]

A permanent magnet-less, brushless synchronous system includes a stator that generates a magnetic rotating field when sourced by an alternating current. An uncluttered rotor disposed within the magnetic rotating field is spaced apart from the stator to form an air gap relative to an axis of rotation. A stationary excitation core spaced apart from the uncluttered rotor by an axial air gap and a radial air gap substantially encloses the stationary excitation core. Some permanent magnet-less, brushless synchronous systems include stator core gaps to reduce axial flux flow. Some permanent magnet-less, brushless synchronous systems include an uncluttered rotor coupled to outer laminations. The quadrature-axis inductance may be increased in some synchronous systems. Some synchronous systems convert energy such as mechanical energy into electrical energy (e.g., a generator); other synchronous systems may convert any form of energy into mechanical energy (e.g., a motor).

Hsu, John S. (Oak Ridge, TN)

2012-02-07T23:59:59.000Z

351

Proper Sustainability: GAP Grant Proposal Work Plan Strategy Webinar  

Office of Energy Efficiency and Renewable Energy (EERE)

In this webinar I will discuss the new GAP grant requirements for tribal environmental programs and strategies for crafting a work plan that focuses on capacity building activities.  My goal is to...

352

Energy gap of Kronig-Penney-type hydrogenated graphene superlattices  

E-Print Network [OSTI]

The electronic structure of graphene-graphane superlattices with armchair interfaces is investigated with first-principles density-functional theory. By separately varying the widths, we find that the energy gap Eg is ...

Lee, Joo-Hyoung

353

Gap generation and semimetal-insulator phase transition in graphene  

E-Print Network [OSTI]

The gap generation is studied in suspended clean graphene in the continuum model for quasiparticles with the Coulomb interaction. We solve the gap equation with the dynamical polarization function and show that, comparing to the case of the static polarization function, the critical coupling constant lowers to the value \\alpha_c=0.92, which is close to that obtained in lattice Monte Carlo simulations. It is argued that additional short-range four-fermion interactions should be included in the continuum model to account for the lattice simulation results. We obtain the critical line in the plane of electromagnetic and four-fermion coupling constants and find a second order phase transition separating zero gap and gapped phases with critical exponents close to those found in lattice calculations.

O. V. Gamayun; E. V. Gorbar; V. P. Gusynin

2009-12-15T23:59:59.000Z

354

Closing gaps in the human genome using sequencing by synthesis  

E-Print Network [OSTI]

The most recent release of the finished human genome contains 260 euchromatic gaps (excluding chromosome Y). Recent work has helped explain a large number of these unresolved regions as 'structural' in nature. Another class ...

Arachchi, Harindra M.

355

Permanent-magnet-less machine having an enclosed air gap  

DOE Patents [OSTI]

A permanent magnet-less, brushless synchronous system includes a stator that generates a magnetic rotating field when sourced by an alternating current. An uncluttered rotor disposed within the magnetic rotating field is spaced apart from the stator to form an air gap relative to an axis of rotation. A stationary excitation core spaced apart from the uncluttered rotor by an axial air gap and a radial air gap substantially encloses the stationary excitation core. Some permanent magnet-less, brushless synchronous systems include stator core gaps to reduce axial flux flow. Some permanent magnet-less, brushless synchronous systems include an uncluttered rotor coupled to outer laminations. The quadrature-axis inductance may be increased in some synchronous systems. Some synchronous systems convert energy such as mechanical energy into electrical energy (e.g., a generator); other synchronous systems may convert any form of energy into mechanical energy (e.g., a motor).

Hsu, John S.

2013-03-05T23:59:59.000Z

356

Orc Notation Structured Wide-Area Programming  

E-Print Network [OSTI]

Orc Notation Structured Wide-Area Programming Jayadev Misra Department of Computer Science University of Texas at Austin http://orc.csres.utexas.edu April 12, 2010 Rennes, France #12;Orc Notation hierarchical structure. #12;Orc Notation Orc · Goal: Internet scripting language. · Next: Component integration

Misra, Jayadev

357

Structured Wide-Area Programming: Orc Calculus  

E-Print Network [OSTI]

Structured Wide-Area Programming: Orc Calculus Jayadev Misra Department of Computer Science University of Texas at Austin http://orc.csres.utexas.edu #12;Concurrency · ubiquitous. · difficult interactions. · Support hierarchical structure. #12;Orc · Initial Goal: Internet scripting language. · Next

Misra, Jayadev

358

Spatial variation of void ratio and shear band thickness in sand using X-ray computed tomography  

SciTech Connect (OSTI)

A detailed study of spatial variation of void ratio and shear band thickness measurements is presented in this paper. A prismatic sand specimen that initially measured 57{center_dot}4 mm wide x 120{center_dot}5 mm long x 182{center_dot}1 mm high was sheared under plane-strain (biaxial) loading conditions. The specimen was prepared at a relative density of 79% using F-75 Ottawa sand. X-ray computed tomography was used to scan the specimen before shearing and after the onset of the shear band. The specimen failed through a single shear band with an inclination angle of 65{center_dot}6{sup o} measured from the direction of the minor principal stress. Computer algorithms were developed to calibrate CT images and quantify void ratio (e) variation within the specimen. CT data analysis revealed cross-sectional spatial variation in void ratio where density is higher in regions close to the edges of the specimen due to membrane effects and confining pressure with no significant variation in void ratio in the axial direction (top to bottom) before shearing. The shear band was easily identified from the CT images, and analysis of void ratio showed a noticeable jump in void ratio profile across the shear band. A detailed statistical summary of the thickness of the shear band and variation of void ratio across the shear band is presented and discussed.

Alshibli, K.A.; Hasan, A. (LSU)

2008-05-01T23:59:59.000Z

359

Excitonic gap, phase transition, and quantum Hall effect in graphene  

E-Print Network [OSTI]

We suggest that physics underlying the recently observed removal of sublattice and spin degeneracies in graphene in a strong magnetic field describes a phase transition connected with the generation of an excitonic gap. The experimental form of the Hall conductivity is reproduced and the main characteristics of the dynamics are described. Predictions of the behavior of the gap as a function of temperature and a gate voltage are made.

V. P. Gusynin; V. A. Miransky; S. G. Sharapov; I. A. Shovkovy

2006-11-23T23:59:59.000Z

360

Hydrogeologic Model for the Gable Gap Area, Hanford Site  

SciTech Connect (OSTI)

Gable Gap is a structural and topographic depression between Gable Mountain and Gable Butte within the central Hanford Site. It has a long and complex geologic history, which includes tectonic uplift synchronous with erosional downcutting associated with the ancestral Columbia River during both Ringold and Cold Creek periods, and by the later Ice Age (mostly glacial Lake Missoula) floods. The gap was subsequently buried and partially backfilled by mostly coarse-grained, Ice Age flood deposits (Hanford formation). Erosional remnants of both the Ringold Formation and Cold Creek unit locally underlie the high-energy flood deposits. A large window exists in the gap where confined basalt aquifers are in contact with the unconfined suprabasalt aquifer. Several paleochannels, of both Hanford and Ringold Formation age, were eroded into the basalt bedrock across Gable Gap. Groundwater from the Central Plateau presently moves through Gable Gap via one or more of these shallow paleochannels. As groundwater levels continue to decline in the region, groundwater flow may eventually be cut off through Gable Gap.

Bjornstad, Bruce N.; Thorne, Paul D.; Williams, Bruce A.; Last, George V.; Thomas, Gregory S.; Thompson, Michael D.; Ludwig, Jami L.; Lanigan, David C.

2010-09-30T23:59:59.000Z

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


361

Quantum-Dot Intermediate-Band Solar Cells with Inverted Band Alignment  

SciTech Connect (OSTI)

The intermediate-band concept was proposed over a decade ago as a possible route to increase the efficiency of single-junction solar cells. Despite a number of experimental attempts to realize this concept, no efficiency improvement over conventional single-junction solar cells has so far been demonstrated. This is likely due to the fact that the intermediate band itself acts to enhance electron-hole recombination. In this work we propose a novel intermediate-band solar-cell architecture based on doped semiconductor nanostructures having an inverted type-I band alignment with the surrounding host. The recombination of carriers in the nanostructures is prevented by ultra-fast charge transfer to the host, thereby removing the main obstacle to achieve high conversion efficiency.

Francheschetti, A.; Lany, S.; Bester, G.

2008-01-01T23:59:59.000Z

362

Investigating the book-tax income gap : factors which affect the gap and details regarding its most significant component  

E-Print Network [OSTI]

(cont.) In total, my thesis suggests that recent changes in the book-tax income gap may be exogenous and transitory, due to changes to the calculation of book income, general business conditions or other factors which ...

Seidman, Jeri

2008-01-01T23:59:59.000Z

363

Direction Dependent Effects In Wide-Field Wideband Full Stokes Radio Imaging  

E-Print Network [OSTI]

Synthesis imaging in radio astronomy is affected by instrumental and atmospheric effects which introduce direction-dependent (DD) gains.The antenna power pattern varies both as a function of time and frequency. The broad band time varying nature of the antenna power pattern when not corrected leads to gross errors in full Stokes imaging and flux estimation. In this poster we explore the errors that arise in image deconvolution while not accounting for the time and frequency dependence of the antenna power pattern. Simulations were conducted with the wide-band full Stokes power pattern of the Karl G. Jansky Very Large Array (VLA) antennas to demonstrate the level of errors arising from direction-dependent gains and their non-neglegible impact on upcoming sky surveys such as the VLASS. DD corrections through hybrid projection algorithms are computationally expensive to perform. A highly parallel implementation through high performance computing architectures is the only feasible way of applying these correction...

Jagannathan, Preshanth; Rau, Urvashi; Taylor, Russ

2014-01-01T23:59:59.000Z

364

X-Band RF Gun Development  

SciTech Connect (OSTI)

In support of the MEGa-ray program at LLNL and the High Gradient research program at SLAC, a new X-band multi-cell RF gun is being developed. This gun, similar to earlier guns developed at SLAC for Compton X-ray source program, will be a standing wave structure made of 5.5 cells operating in the pi mode with copper cathode. This gun was designed following criteria used to build SLAC X-band high gradient accelerating structures. It is anticipated that this gun will operate with surface electric fields on the cathode of 200 MeV/m with low breakdown rate. RF will be coupled into the structure through a final cell with symmetric duel feeds and with a shape optimized to minimize quadrupole field components. In addition, geometry changes to the original gun, operated with Compton X-ray source, will include a wider RF mode separation, reduced surface electric and magnetic fields.

Vlieks, Arnold; Dolgashev, Valery; Tantawi, Sami; /SLAC; Anderson, Scott; Hartemann, Fred; Marsh, Roark; /LLNL, Livermore

2012-06-22T23:59:59.000Z

365

Permanent magnet focused X-band photoinjector  

DOE Patents [OSTI]

A compact high energy photoelectron injector integrates the photocathode directly into a multicell linear accelerator with no drift space between the injection and the linac. High electron beam brightness is achieved by accelerating a tightly focused electron beam in an integrated, multi-cell, X-band rf linear accelerator (linac). The photoelectron linac employs a Plane-Wave-Transformer (PWT) design which provides strong cell-to-cell coupling, easing manufacturing tolerances and costs.

Yu, David U. L. (Rancho Palos Verdes, CA); Rosenzweig, James (Los Angeles, CA)

2002-09-10T23:59:59.000Z

366

The Negative Parity Bands in $^{156}$Gd  

E-Print Network [OSTI]

The high flux reactor of the Institut Laue-Langevin is the world most intense neutron source for research. Using the ultra high-resolution crystal spectrometers GAMS installed at the in-pile target position H6/H7 it is possible to measure nuclear state lifetimes using the Gamma Ray Induced Recoil (GRID) technique. In bent crystal mode, the spectrometers allow to perform spectroscopy with a dynamic range of up to six orders magnitude. At a very well collimated external neutron beam it is possible to install a highly efficient germanium detector array to obtain coincidences and angular correlations. The mentioned techniques were used to study the first two negative parity bands in $^{156}$Gd. These bands have been in the focus of interest since they seem to show signatures of a tetrahedral symmetry. A surprisingly high B(E2) value of about 1000 W.u. for the $4^- \\rightarrow 2^-$ transition was discovered. It indicates that the two first negative parity bands cannot be considered to be signature partners.

Michael Jentschel; Loic Sengele; Dominique Curien; Jerzy Dudek; Florent Haas

2014-04-23T23:59:59.000Z

367

Broad Band Photon Harvesting Biomolecules for Photovoltaics  

E-Print Network [OSTI]

We discuss the key principles of artificial photosynthesis for photovoltaic energy conversion. We demonstrate these principles by examining the operation of the so-called "dye sensitized solar cell" (DSSC) - a photoelectrochemical device which simulates the charge separation process across a nano-structured membrane that is characteristic of natural systems. These type of devices have great potential to challenge silicon semiconductor technology in the low cost, medium efficiency segment of the PV market. Ruthenium charge transfer complexes are currently used as the photon harvesting components in DSSCs. They produce a relatively broad band UV and visible response, but have long term stability problems and are expensive to manufacture. We suggest that a class of biological macromolecules called the melanins may be suitable replacements for the ruthenium complexes. They have strong, broad band absorption, are chemically and photochemically very stable, can be cheaply and easily synthesized, and are also bio-available and bio-compatible. We demonstrate a melanin-based regenerative solar cell, and discuss the key properties that are necessary for an effective broad band photon harvesting system.

P. Meredith; B. J. Powell; J. Riesz; R. Vogel; D. Blake; I. Kartini; G. Will; S. Subianto

2004-06-04T23:59:59.000Z

368

WORLD WIDE WEB 2.3 Web  

E-Print Network [OSTI]

H I2 C WORLD WIDE WEB 1996 #12; 1. 1.1 I2 Cnet 1.2 1.3 WWW 2 2.1 2.2 2.3 Web 2.4 3 O 3.1 3.2 3.3 3.4 O Web browsers. 4. 4.1 4.2 4 File System 9.6 10 A. Web browser HTT . B A #12

Markatos, Evangelos P.

369

Enterprise-Wide Agreements | Department of Energy  

Energy Savers [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 Delicious RankCombustion |Energy UsageAUDITVehicles » AlternativeUpDrain-WaterDepartmentEnterprise-Wide Agreements

370

Potential “ways of thinking” about the shear-banding phenomenon  

E-Print Network [OSTI]

Shear-banding is a curious but ubiquitous phenomenon occurring in soft matter. The phenomenological similarities between the shear-banding transition and phase transitions has pushed some researchers to adopt a ‘thermodynamical’ ...

Fardin, M. A.

371

Gap formation and stability in non-isothermal protoplanetary discs  

E-Print Network [OSTI]

Several observations of transition discs show lopsided dust-distributions. A potential explanation is the formation of a large-scale vortex acting as a dust-trap at the edge of a gap opened by a giant planet. Numerical models of gap-edge vortices have thus far employed locally isothermal discs, but the theory of this vortex-forming or `Rossby wave' instability was originally developed for adiabatic discs. We generalise the study of planetary gap stability to non-isothermal discs using customised numerical simulations of disc-planet systems where the planet opens an unstable gap. We include in the energy equation a simple cooling function with cooling timescale $t_c=\\beta\\Omega_k^{-1}$, where $\\Omega_k$ is the Keplerian frequency, and examine the effect of $\\beta$ on the stability of gap edges and vortex lifetimes. We find increasing $\\beta$ lowers the growth rate of non-axisymmetric perturbations, and the dominant azimuthal wavenumber $m$ decreases. We find a quasi-steady state consisting of one large-scale, ...

Les, Robert

2015-01-01T23:59:59.000Z

372

CV evolution: AM Her binaries and the period gap  

E-Print Network [OSTI]

AM Her variables -- synchronised magnetic cataclysmic variables (CVs) -- exhibit a different period distribution from other CVs across the period gap. We show that non-AM Her systems may infiltrate the longer-period end of the period gap if they are metal-deficient, but that the position and width of the gap in orbital period is otherwise insensitive to other binary parameters (excepting the normalisation of the braking rate). In AM Her binaries, magnetic braking is reduced as the wind from the secondary star may be trapped within the magnetosphere of the white dwarf primary. This reduced braking fills the period gap from its short-period end as the dipole magnetic moment of the white dwarf increases. The consistency of these models with the observed distribution of CVs, both AM Her and non-AM Her type, provides compelling evidence supporting magnetic braking as the agent of angular momentum loss among long-period CVs, and its disruption as the explanation of the 2 - 3 hour period gap among nonmagnetic CVs.

R. F. Webbink; D. T. Wickramasinghe

2002-04-19T23:59:59.000Z

373

Simulating Interface Growth and Defect Generation in CZT – Simulation State of the Art and Known Gaps  

SciTech Connect (OSTI)

This one-year, study topic project will survey and investigate the known state-of-the-art of modeling and simulation methods suitable for performing fine-scale, fully 3-D modeling, of the growth of CZT crystals at the melt-solid interface, and correlating physical growth and post-growth conditions with generation and incorporation of defects into the solid CZT crystal. In the course of this study, this project will also identify the critical gaps in our knowledge of modeling and simulation techniques in terms of what would be needed to be developed in order to perform accurate physical simulations of defect generation in melt-grown CZT. The transformational nature of this study will be, for the first time, an investigation of modeling and simulation methods for describing microstructural evolution during crystal growth and the identification of the critical gaps in our knowledge of such methods, which is recognized as having tremendous scientific impacts for future model developments in a wide variety of materials science areas.

Henager, Charles H.; Gao, Fei; Hu, Shenyang Y.; Lin, Guang; Bylaska, Eric J.; Zabaras, Nicholas

2012-11-01T23:59:59.000Z

374

Quebec Recovery of White-Fronted Goose Banded in Greenland  

E-Print Network [OSTI]

O. H. Hewitt Journal:  Bird Banding Volume:  19 Issue:  3 (July) Section:  General Notes Year:  1948 Pages:  124

375

Arctic Tern Banded in Greenland, Recovered in Ontario  

E-Print Network [OSTI]

T. M. Shortt Journal:  Bird Banding Volume:  20 Issue:  1 (January) Section:  General Notes Year:  1949 Pages:  50

376

WIRELESS MINE-WIDE TELECOMMUNICATIONS TECHNOLOGY  

SciTech Connect (OSTI)

A comprehensive mine-wide, two-way wireless voice and data communication system for the underground mining industry was developed. The system achieves energy savings through increased productivity and greater energy efficiency in meeting safety requirements within mines. The mine-wide system is comprised of two interfaced subsystems: a through-the-earth communications system and an in-mine communications system. The mine-wide system permits two-way communication among underground personnel and between underground and surface personnel. The system was designed, built, and commercialized. Several systems are in operation in underground mines in the United States. The use of these systems has proven they result in considerable energy savings. A system for tracking the location of vehicles and people within the mine was also developed, built and tested successfully. Transtek's systems are being used by the National Institute of Occupational Safety and Health (NIOSH) in their underground mine rescue team training program. This project also resulted in a spin-off rescue team lifeline and communications system. Furthermore, the project points the way to further developments that can lead to a GPS-like system for underground mines allowing the use of autonomous machines in underground mining operations, greatly reducing the amount of energy used in these operations. Some products developed under this program are transferable to applications in fields other than mining. The rescue team system is applicable to use by first responders to natural, accidental, or terrorist-caused building collapses. The in-mine communications system can be installed in high-rise buildings providing in-building communications to security and maintenance personnel as well as to first responders.

Zvi H. Meiksin

2004-03-01T23:59:59.000Z

377

Concave nanomagnets with widely tunable anisotropy  

SciTech Connect (OSTI)

A nanomagnet having widely tunable anisotropy is disclosed. The disclosed nanomagnet is a magnetic particle with a convex shape having a first magnetically easy axis. The convex shape is modified to include at least one concavity to urge a second magnetically easy axis to form substantially offset from the first magnetically easy axis. In at least one embodiment, the convex shape is also modified to include at least one concavity to urge a second magnetically easy axis to form with a magnetic strength substantially different from the first magnetically easy axis.

Lambson, Brian; Gu, Zheng; Carlton, David; Bokor, Jeffrey

2014-07-01T23:59:59.000Z

378

World Wide Web( WWW ) Greenberg Web  

E-Print Network [OSTI]

WWW 1 World Wide Web( WWW ) WWW Web Web Greenberg Web 30% [1] Web WWW Web WWW [2] [3] WWW 2 2.1 WWW Web 1 1: · 1 · 1 #12;· Web Web 2: 2 2 Web 2.2 Web Web URL URL .html / Yahoo http://headlines.yahoo.co.jp/hl?a=2 0011205-00000101-yom-soci URL onmouseover on- mouseout JavaScript 2.1 2.3 URL URL 1. Web HTML 2. 1

Shirai, Kiyoaki

379

Modern testing meets wide range of objectives  

SciTech Connect (OSTI)

Testing sequences in two very different wells illustrate the wide range of objectives that are met with modern testing procedures. The first example is a drill stem test in an exploration well. The second test is in an established producing well. The exploration well test incorporated tubing-conveyed perforating, fluid sampling, production logging, and matrix stimulation to evaluate and properly treat near-well bore damage, as well as to investigate reservoir volume and characterize boundaries. The test on the established producer evaluated whether a workover could remedy lower than expected productivity. Production logging was combined with stationary transient measurements.

Ehlig-Economides, C.A.; Hegeman, P. (Schlumberger Oilfield Services, Houston, TX (United States)); Clark, G. (Schlumberger Oilfield Services, Aberdeen (United Kingdom))

1994-08-01T23:59:59.000Z

380

Discontinuous Buckling of Wide Beams and Metabeams  

E-Print Network [OSTI]

We uncover how nonlinearities dramatically influence the buckling of elastic beams by means of experiments, simulations and theory. We show that sufficiently wide, ordinary elastic beams exhibit discontinuous buckling, an unstable form of buckling where the post-buckling stiffness is negative. We develop a 1D model that matches our data and identify nonlinearity as the main cause for negative stiffness. Finally, we create nonlinear metamaterials that allow us to rationally design the (negative) post-buckling stiffness of metabeams, independently of beam thickness, and demonstrate discontinuous buckling for metabeams as slender as 1% numerically and 5% experimentally.

Corentin Coulais; Johannes T. B. Overvelde; Luuk A. Lubbers; Katia Bertoldi; Martin van Hecke

2014-10-22T23:59:59.000Z

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381

Wide Bandgap Power Electronics | Department of Energy  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment of Energy WhileTanklessLES'NeighborhoodThisApril2014Why Give?Wide9

382

Wide Bandgap Semiconductors: Pursuing the Promise  

Office of Environmental Management (EM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of EnergyEnergyENERGYWomen Owned SmallOf TheViolations | Department of Energyis EIA?WhiteWhoWide Bandgap

383

Wide Electrochemical Window Solvents - Energy Innovation Portal  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched FerromagnetismWaste and MaterialsWenjun DengWISP SignInWho do IWhyWhy: TheWide

384

Excitation of Banded Whistler Waves in the Magnetosphere  

SciTech Connect (OSTI)

Banded whistler waves can be generated by the whistler anisotropy instability driven by two bi-Maxwellian electron components with T{sub {perpendicular}}/T{sub {parallel}} > 1 at different T{sub {parallel}} For typical magnetospheric condition of 1 < {omega}{sub e}/{Omega}{sub e} < 5 in regions associated with strong chorus, upper-band waves can be excited by anisotropic electrons below {approx} 1 keV, while lower-band waves are excited by anisotropic electrons above {approx} 10 keV. Lower-band waves are generally field-aligned and substantially electromagnetic, while upper-band waves propagate obliquely and have quasi-electrostatic fluctuating electric fields. The quasi-electrostatic feature of upper-band waves suggests that they may be more easily identified in electric field observations than in magnetic field observations. Upper-band waves are liable to Landau damping and the saturation level of upperband waves is lower than lower-band waves, consistent with observations that lower-band waves are stronger than upper-band waves on average. The oblique propagation, the lower saturation level, and the more severe Landau damping together would make upper-band waves more tightly confined to the geomagnetic equator (|{lambda}{sub m}| < {approx}10{sup o}) than lower-band waves.

Gary, S. Peter [Los Alamos National Laboratory; Liu, Kaijun [Los Alamos National Laboratory; Winske, Dan [Los Alamos National Laboratory

2012-07-13T23:59:59.000Z

385

Anisotropy of strong pinning in multi-band superconductors  

E-Print Network [OSTI]

pinning in multi-band superconductors 2 1. Introduction The multi-band nature of superconductivity in iron the anisotropy of superconducting parameters in the iron-based superconductors. In particular, Kidzun et al. [23Anisotropy of strong pinning in multi-band superconductors C.J. van der Beek, M. Konczykowski

Boyer, Edmond

386

Vortex and gap generation in gauge models of graphene  

E-Print Network [OSTI]

Effective quantum field theoretical continuum models for graphene are investigated. The models include a complex scalar field and a vector gauge field. Different gauge theories are considered and their gap patterns for the scalar, vector, and fermion excitations are investigated. Different gauge groups lead to different relations between the gaps, which can be used to experimentally distinguish the gauge theories. In this class of models the fermionic gap is a dynamic quantity. The finite-energy vortex solutions of the gauge models have the flux of the "magnetic field" quantized, making the Bohm-Aharonov effect active even when external electromagnetic fields are absent. The flux comes proportional to the scalar field angular momentum quantum number. The zero modes of the Dirac equation show that the gauge models considered here are compatible with fractionalization.

O. Oliveira; C. E. Cordeiro; A. Delfino; W. de Paula; T. Frederico

2010-12-21T23:59:59.000Z

387

NGNP Project Regulatory Gap Analysis for Modular HTGRs  

SciTech Connect (OSTI)

The Next Generation Nuclear Plant (NGNP) Project Regulatory Gap Analysis (RGA) for High Temperature Gas-Cooled Reactors (HTGR) was conducted to evaluate existing regulatory requirements and guidance against the design characteristics specific to a generic modular HTGR. This final report presents results and identifies regulatory gaps concerning current Nuclear Regulatory Commission (NRC) licensing requirements that apply to the modular HTGR design concept. This report contains appendices that highlight important HTGR licensing issues that were found during the RGA study. The information contained in this report will be used to further efforts in reconciling HTGR-related gaps in the NRC licensing structure, which has to date largely focused on light water reactor technology.

Wayne Moe

2011-09-01T23:59:59.000Z

388

Finite-temperature lineshapes in gapped quantum spin chains  

E-Print Network [OSTI]

We consider the finite-temperature dynamical structure factor (DSF) of gapped quantum spin chains such as the spin one Heisenberg model and the transverse field Ising model in the disordered phase. At zero temperature the DSF in these models is dominated by a delta-function line arising from the coherent propagation of single particle modes. Using methods of integrable quantum field theory we determine the evolution of the lineshape at low temperatures. We show that the line shape is in general asymmetric in energy and becomes Lorentzian only at temperatures far below the gap. We discuss the relevance of our results for the analysis of inelastic neutron scattering experiments on gapped spin chain systems such as CsNiCl_3 and YBaNiO_5.

Fabian H. L. Essler; Robert M. Konik

2007-12-05T23:59:59.000Z

389

Lower bounds to the spectral gap of Davies generators  

SciTech Connect (OSTI)

We construct lower bounds to the spectral gap of a family of Lindblad generators known as Davies maps. These maps describe the thermalization of quantum systems weakly coupled to a heat bath. The steady state of these systems is given by the Gibbs distribution with respect to the system Hamiltonian. The bounds can be evaluated explicitly, when the eigenbasis and the spectrum of the Hamiltonian is known. A crucial assumption is that the spectrum of the Hamiltonian is non-degenerate. Furthermore, we provide a counterexample to the conjecture, that the convergence rate is always determined by the gap of the associated Pauli master equation. We conclude that the full dynamics of the Lindblad generator has to be considered. Finally, we present several physical example systems for which the bound to the spectral gap is evaluated.

Temme, Kristan [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2013-12-15T23:59:59.000Z

390

Room temperature ferromagnetism in Co-doped amorphous carbon composites from the spin polarized semiconductor band  

SciTech Connect (OSTI)

This study provides conclusive evidence of room temperature ferromagnetism in Co-doped amorphous carbon (a-C) composites from the spin polarized semiconductor band. These composites are constructed from discontinuous [Co(3?nm)/a-C(d{sub c} nm)]{sub 5} multilayers with d{sub c}?=?3?nm and d{sub c}?=?6?nm. Only remnant circular dichroism (CD) was observed from the d{sub c}?=?3?nm sample but not when d{sub c}?=?6?nm. In addition, the remnant CD peaks at 5.5?eV, which is comparable with the absorption peak associated with the C ?-?* gap transition. We suggest that the possible mechanism for this coupling can be considered as a magnetic proximity effect in which a ferromagnetic moment in the C medium is induced by Co/C interfaces.

Hsu, H. S., E-mail: hshsu@mail.nptu.edu.tw; Chien, P. C.; Chang, Y. Y. [Department of Applied Physics, National Pingtung University, Pingtung 900, Taiwan (China); Sun, S. J. [Department of Applied Physics, National University of Kaohsiung, Kaohsiung 811, Taiwan (China); Lee, C. H. [Department of Engineering and System Science, National Tsing-Hua University, Hsinchu 300, Taiwan (China)

2014-08-04T23:59:59.000Z

391

Dual Band Electrodes in Generator-Collector Mode: Simultaneous Measurement of Two Species  

E-Print Network [OSTI]

A computational model for the simulation of a double band collector-generator experiment is applied to the situation where two electrochemical reactions occur concurrently. It is shown that chronoamperometric measurements can be used to take advantage of differences in diffusion coefficients to measure the concentrations of both electroactive species simultaneously, by measuring the time at which the collection efficiency reaches a specific value. The separation of the electrodes is shown to not affect the sensitivity of the method (in terms of percentage changes in the measured time to reach the specified collection efficiency), but wider gaps can provide a greater range of (larger) absolute values of this characteristic time. It is also shown that measuring the time taken to reach smaller collection efficiencies can allow for the detection of smaller amounts of whichever species diffuses faster. The case of a system containing both ascorbic acid and opamine in water is used to exemplify the method, and it i...

Barnes, Edward O; Dale, Sara E C; Marken, Frank; Compton, Richard G

2013-01-01T23:59:59.000Z

392

2009 Voluntary Protection Programs Participants' Association (VPPPA) Presentation: Gaps in your Safety Program?  

Broader source: Energy.gov [DOE]

2009 Voluntary Protection Programs Participants' Association (VPPPA) Presentation: Gaps in your Safety Program?

393

W-Band Sheet Beam Klystron Design  

SciTech Connect (OSTI)

Sheet beam devices provide important advantages for very high power, narrow bandwidth RF sources like accelerator klystrons [1]. Reduced current density and increased surface area result in increased power capabi1ity, reduced magnetic fields for focusing and reduced cathode loading. These advantages are offset by increased complexity, beam formation and transport issues and potential for mode competition in the ovennoded cavities and drift tube. This paper will describe the design issues encountered in developing a 100 kW peak and 2 kW average power sheet beam k1ystron at W-band including beam formation, beam transport, circuit design, circuit fabrication and mode competition.

Scheitrum, G.; Caryotakis, G.; Burke, A.; Jensen, A.; Jongewaard, E.a Krasnykh, A.; Neubauer, M.; Phillips, R.; Rauenbuehler, K.; /SLAC

2011-11-11T23:59:59.000Z

394

An X-band overmoded relativistic klystron  

SciTech Connect (OSTI)

An X-band overmoded relativistic klystron is proposed, the operation mode of which is the TM{sub 02} mode. The drift tube could not cut off the TM{sub 01} mode; isolating the buncher cavity from the input cavity is achieved by introducing a sectional RF lossy material. Microwaves are extracted from the modulated electron beam using a cylindrical waveguide, rather than a coaxial waveguide; thereby, the output structure is significantly simplified. Particle-in-cell simulations show that microwaves with power of 1.28?GW and frequency of 9.30?GHz can be obtained, corresponding to an efficiency of 32% and relative bandwidth of about 8%.

Xiao, Renzhen; Chen, Changhua; Li, Jiawei; Bai, Xianchen [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Deng, Yuqun [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

2014-11-15T23:59:59.000Z

395

The gender gap on concept inventories in physics: what is consistent, what is inconsistent, and what factors influence the gap?  

E-Print Network [OSTI]

We review the literature on the gender gap on concept inventories in physics. Across studies, men consistently score higher on pre-tests of the Force Concept Inventory (FCI) and Force and Motion Conceptual Evaluation (FMCE) by about 10%, and in most cases score higher on post-tests as well, also by about 10%. The average difference in normalized gain is about 6%. This difference is much smaller than the average difference in normalized gain between traditional lecture and interactive engagement (25%), but is large enough that it could impact the results of studies comparing the effectiveness of different teaching methods. Based on our analysis of 24 published articles comparing the impact of 34 factors that could potentially influence the gender gap, no single factor is sufficient to explain the gap. Several high-profile studies that have claimed to account for or reduce the gender gap have failed to be replicated, suggesting that isolated claims of explanations of the gender gap should be interpreted with ca...

Madsen, Adrian; Sayre, Eleanor C

2013-01-01T23:59:59.000Z

396

Effective Community-Wide Policy Technical Assistance: The NREL...  

Open Energy Info (EERE)

Wide Policy Technical Assistance: The NRELDOE Approach Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Effective Community-Wide Policy Technical Assistance: The NREL...

397

Proposed Energy Transport Corridors: West-wide energy corridor...  

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

Energy Transport Corridors: West-wide energy corridor programmatic EIS, Draft Corridors - September 2007. Proposed Energy Transport Corridors: West-wide energy corridor...

398

Webinar: Opportunities for Wide Bandgap Semiconductor Power Electronic...  

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

Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications Webinar: Opportunities for Wide Bandgap Semiconductor Power Electronics...

399

DOE Issues Final Site-Wide Environmental Impact Statement for...  

Office of Environmental Management (EM)

DOE Issues Final Site-Wide Environmental Impact Statement for the Nevada National Security Site DOE Issues Final Site-Wide Environmental Impact Statement for the Nevada National...

400

Networking and the Web World-Wide Web  

E-Print Network [OSTI]

Networking and the Web #12;World-Wide Web · Wide use of computers Web · Key components of the web ­ Computer Communica8on Networks

North Carolina at Chapel Hill, University of

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


401

Lesson Learned by Environmental Management Complex-wide Activity...  

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

Environmental Management Complex-wide Activity-level Work Planning and Control Lesson Learned by Environmental Management Complex-wide Activity-level Work Planning and Control...

402

Commonwealth Aluminum: Manufacturer Conducts Plant-Wide Energy...  

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

Commonwealth Aluminum: Manufacturer Conducts Plant-Wide Energy Assessments at Two Aluminum Sheet Production Operations Commonwealth Aluminum: Manufacturer Conducts Plant-Wide...

403

THE 0.5-2.22 {mu}m SCATTERED LIGHT SPECTRUM OF THE DISK AROUND TW Hya: DETECTION OF A PARTIALLY FILLED DISK GAP AT 80 AU  

SciTech Connect (OSTI)

We present a 0.5-2.2 {mu}m scattered light spectrum of the circumstellar disk around TW Hya from a combination of spatially resolved Hubble Space Telescope STIS spectroscopy and NICMOS coronagraphic images of the disk. We investigate the morphology of the disk at distances >40 AU over this wide range of wavelengths, and identify the presence of a depression in surface brightness at {approx}80 AU that could be caused by a gap in the disk. Additionally, we quantify the surface brightness, azimuthal symmetry, and spectral character of the disk as a function of radius. Our analysis shows that the scattering efficiency of the dust is largely neutral to blue over the observed wavelengths. We model the disk as a steady {alpha}-disk with an ad hoc gap structure. The thermal properties of the disk are self-consistently calculated using a three-dimensional radiative transfer code that uses ray tracing to model the heating of the disk interior and scattered light images. We find a good fit to the data over a wide range of distances from the star if we use a model disk with a partially filled gap of 30% depth at 80 AU and with a self-similar truncation knee at 100 AU. The origin of the gap is unclear, but it could arise from a transition in the nature of the disk's dust composition or the presence of a planetary companion. Based on scalings to previous hydrodynamic simulations of gap-opening criteria for embedded proto-planets, we estimate that a planetary companion forming the gap could have a mass between 6 and 28 M{sub Circled-Plus }.

Debes, John H. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Jang-Condell, Hannah [University of Wyoming, Laramie, WY 82071 (United States); Weinberger, Alycia J. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015 (United States); Roberge, Aki [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Schneider, Glenn [Steward Observatory, University of Arizona, Tuscon, AZ 85721 (United States)

2013-07-01T23:59:59.000Z

404

WIDE-FIELD ASTRONOMICAL MULTISCALE CAMERAS  

SciTech Connect (OSTI)

In order to produce sufficiently low aberrations with a large aperture, telescopes have a limited field of view. Because of this narrow field, large areas of the sky at a given time are unobserved. We propose several telescopes based on monocentric reflective, catadioptric, and refractive objectives that may be scaled to wide fields of view and achieve 1.''1 resolution, which in most locations is the practical seeing limit of the atmosphere. The reflective and Schmidt catadioptric objectives have relatively simple configurations and enable large fields to be captured at the expense of the obscuration of the mirror by secondary optics, a defect that may be managed by image plane design. The refractive telescope design does not have an obscuration but the objective has substantial bulk. The refractive design is a 38 gigapixel camera which consists of a single monocentric objective and 4272 microcameras. Monocentric multiscale telescopes, with their wide fields of view, may observe phenomena that might otherwise be unnoticed, such as supernovae, glint from orbital space debris, and near-earth objects.

Marks, Daniel L.; Brady, David J., E-mail: dbrady@ee.duke.edu [Department of Electrical and Computer Engineering and Fitzpatrick Institute for Photonics, Box 90291, Duke University, Durham, NC 27708 (United States)

2013-05-15T23:59:59.000Z

405

Progress of the ITER equatorial vis/IR wide angle viewing system optical design  

SciTech Connect (OSTI)

The equatorial vis/IR wide angle viewing system is present in four ITER diagnostic equatorial ports. This instrument will cover a large field of view with high spatial and temporal resolutions, to provide real time temperature measurements of plasma facing components, spectral data in the visible range, information on runaway electrons, and pellet tracking. This diagnostic needs to be reliable, precise, and long lasting. Its design is driven by both the tokamak severe environment and the high performances required for machine protection. The preliminary design phase is ongoing. Paramount issues are being tackled, relative to wide spectral band optical design, material choice, and optomechanical difficulties due to the limited space available for this instrument in the ports, since many other diagnostics and services are also present. Recent progress of the diagnostic optical design and status of associated R and D are presented.

Davi, M.; Corre, Y.; Guilhem, D.; Jullien, F.; Reichle, R.; Salasca, S.; Travere, J. M. [Association Euratom CEA, CEA/DSM/IRFM, Cadarache, 13108 Saint-Paul-lez-Durance (France); Cal, E. de la; Manzanares, A.; Pablos, J. L. de [Association Euratom CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Migozzi, J. B. [JBM Optique, 11 Av. de la division Leclerc, 92310 Sevres (France)

2008-10-15T23:59:59.000Z

406

Sub-10-nanometre metallic gaps for use in molecular electronics  

E-Print Network [OSTI]

gaps as small as sub-10 nm. Image from (8). Gaps can also be created by trapping gold nanoparticles between large-separation electrodes using an AC field, and then breaking the bridge by applying a large DC 5 1.2 Review of Related Work voltage (16... .3 Simmons Tunnelling Model grown QDs because their local environment is more stable. This susceptibility to electric fields will be apparent in our measurements, as discussed in 7.6. No matter the nature of the excitation, QDs may emit photons when...

Curtis, Kellye Suzanne

2012-07-03T23:59:59.000Z

407

Rapidity gap survival in the black-disk regime  

SciTech Connect (OSTI)

We summarize how the approach to the black-disk regime (BDR) of strong interactions at TeV energies influences rapidity gap survival in exclusive hard diffraction pp -> p + H + p (H = dijet, Qbar Q, Higgs). Employing a recently developed partonic description of such processes, we discuss (a) the suppression of diffraction at small impact parameters by soft spectator interactions in the BDR; (b) further suppression by inelastic interactions of hard spectator partons in the BDR; (c) correlations between hard and soft interactions. Hard spectator interactions substantially reduce the rapidity gap survival probability at LHC energies compared to previously reported estimates.

Leonid Frankfurt; Charles Hyde; Mark Strikman; Christian Weiss

2007-04-16T23:59:59.000Z

408

Multi-gap high impedance plasma opening switch  

DOE Patents [OSTI]

A high impedance plasma opening switch having an anode and a cathode and at least one additional electrode placed between the anode and cathode is disclosed. The presence of the additional electrodes leads to the creation of additional plasma gaps which are in series, increasing the net impedance of the switch. An equivalent effect can be obtained by using two or more conventional plasma switches with their plasma gaps wired in series. Higher impedance switches can provide high current and voltage to higher impedance loads such as plasma radiation sources. 12 figs.

Mason, R.J.

1996-10-22T23:59:59.000Z

409

Multi-gap high impedance plasma opening switch  

DOE Patents [OSTI]

A high impedance plasma opening switch having an anode and a cathode and at least one additional electrode placed between the anode and cathode. The presence of the additional electrodes leads to the creation of additional plasma gaps which are in series, increasing the net impedance of the switch. An equivalent effect can be obtained by using two or more conventional plasma switches with their plasma gaps wired in series. Higher impedance switches can provide high current and voltage to higher impedance loads such as plasma radiation sources.

Mason, Rodney J. (Los Alamos, NM)

1996-01-01T23:59:59.000Z

410

The role of the energy gap in protein folding dynamics  

E-Print Network [OSTI]

The dynamics of folding of proteins is studied by means of a phenomenological master equation. The energy distribution is taken as a truncated exponential for the misfolded states plus a native state sitting below the continuum. The influence of the gap on the folding dynamics is studied, for various models of the transition probabilities between the different states of the protein. We show that for certain models, the relaxation to the native state is accelerated by increasing the gap, whereas for others it is slowed down .

Estelle Pitard; Henri Orland

1998-11-17T23:59:59.000Z

411

Rotational bands with identical transition energies in actinide nuclei  

SciTech Connect (OSTI)

We point out the existence of ground-state rotational bands with identical transition energies (up to spin 8{h bar}) in {sup 240}Pu, {sup 244}Cm, {sup 246}Cm, and {sup 250}Cf. The corresponding transitions in the ground-state bands of {sup 236}U and {sup 238}U have identical energies (within {similar to}2 keV) up to spin 24{h bar}. These features are very similar to those recently observed for superdeformed bands in the mass-150 and mass-190 regions and suggest that the phenomenon of identical bands is not restricted to superdeformed bands.

Ahmad, I.; Carpenter, M.P.; Chasman, R.R.; Janssens, R.V.F.; Khoo, T.L. (Argonne National Laboratory, Argonne, Illinois (USA))

1991-09-01T23:59:59.000Z

412

Hybrid Band effects program (Lockheed Martin shared vision CRADA)  

SciTech Connect (OSTI)

Hybrid Band{trademark} (H-band) is a Lockheed Martin Missiles and Fire Control (LMMFC) designation for a specific RF modulation that causes disruption of select electronic components and circuits. H-Band enables conventional high-power microwave (HPM) effects (with a center frequency of 1 to 2 GHz, for example) using a higher frequency carrier signal. The primary technical objective of this project was to understand the fundamental physics of Hybrid Band{trademark} Radio Frequency effects on electronic systems. The follow-on objective was to develop and validate a Hybrid Band{trademark} effects analysis process.

Bacon, L. D.

2012-03-01T23:59:59.000Z

413

Puzzling Phenomenon of Diffuse Interstellar Bands  

E-Print Network [OSTI]

The discovery of the first diffuse interstellar bands (DIBs) dates back to the pioneering years of stellar spectroscopy. Today, we know about 300 absorption structures of this kind. There exists a great variety of the profiles and intensities of DIBs, so they can not be readily described, classified or characterized. To the present day no reliable identification of the DIBs' carriers has been found. Many carriers of DIBs have been proposed over the years. They ranged from dust grains to free molecules of different kinds, and to more exotic specimens, like hydrogen negative ion. Unfortunately, none of them is responsible for observed DIBs. Furthermore, it was shown that a single carrier cannot be responsible for all known DIBs. It is hard to estimate how many carriers can participate in producing these bands. The problem is further complicated by the fact that to this day it is still impossible to find any laboratory spectrum of any substance which would match the astrophysical spectra. Here, a historical outline concerning DIBs is followed by a brief description of their whole population. Then, a special attention is focused on the procedures trying to extract spectroscopic families within the set of all known DIBs.

B. Wszolek

2007-12-10T23:59:59.000Z

414

Band offsets of Al{sub 2}O{sub 3} and HfO{sub 2} oxides deposited by atomic layer deposition technique on hydrogenated diamond  

SciTech Connect (OSTI)

High-k oxide insulators (Al{sub 2}O{sub 3} and HfO{sub 2}) have been deposited on a single crystalline hydrogenated diamond (H-diamond) epilayer by an atomic layer deposition technique at temperature as low as 120 Degree-Sign C. Interfacial electronic band structures are characterized by X-ray photoelectron spectroscopy. Based on core-level binding energies and valence band maximum values, valence band offsets are found to be 2.9 {+-} 0.2 and 2.6 {+-} 0.2 eV for Al{sub 2}O{sub 3}/H-diamond and HfO{sub 2}/H-diamond heterojunctions, respectively. Band gaps of the Al{sub 2}O{sub 3} and HfO{sub 2} have been determined to be 7.2 {+-} 0.2 and 5.4 {+-} 0.2 eV by measuring O 1s energy loss spectra, respectively. Both the Al{sub 2}O{sub 3}/H-diamond and HfO{sub 2}/H-diamond heterojunctions are concluded to be type-II staggered band configurations with conduction band offsets of 1.2 {+-} 0.2 and 2.7 {+-} 0.2 eV, respectively.

Liu, J. W.; Liao, M. Y.; Imura, M. [Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Koide, Y. [Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Nanofabrication Platform, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Center of Materials Research for Low Carbon Emission, NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

2012-12-17T23:59:59.000Z

415

The origin of 2.7 eV luminescence and 5.2 eV excitation band in hafnium oxide  

SciTech Connect (OSTI)

The origin of a blue luminescence band at 2.7 eV and a luminescence excitation band at 5.2 eV of hafnia has been studied in stoichiometric and non-stoichiometric hafnium oxide films. Experimental and calculated results from the first principles valence band spectra showed that the stoichiometry violation leads to the formation of the peak density of states in the band gap caused by oxygen vacancies. Cathodoluminescence in the non-stoichiometric film exhibits a band at 2.65 eV that is excited at the energy of 5.2 eV. The optical absorption spectrum calculated for the cubic phase of HfO{sub 2} with oxygen vacancies shows a peak at 5.3?eV. Thus, it could be concluded that the blue luminescence band at 2.7?eV and HfO{sub x} excitation peak at 5.2?eV are due to oxygen vacancies. The thermal trap energy in hafnia was estimated.

Perevalov, T. V., E-mail: timson@isp.nsc.ru [A. V. Rzhanov Institute of Semiconductor Physics of SB RAS, 13 Lavrentieva Ave, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk (Russian Federation); Aliev, V. Sh.; Gritsenko, V. A. [A. V. Rzhanov Institute of Semiconductor Physics of SB RAS, 13 Lavrentieva Ave, 630090 Novosibirsk (Russian Federation); Saraev, A. A. [Boreskov Institute of Catalysis of SB RAS, 5 Lavrentieva Ave, 630090 Novosibirsk (Russian Federation); Kaichev, V. V. [Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk (Russian Federation); Boreskov Institute of Catalysis of SB RAS, 5 Lavrentieva Ave, 630090 Novosibirsk (Russian Federation); Ivanova, E. V.; Zamoryanskaya, M. V. [Ioffe Physicotechnical Institute of RAS, 26 Politechnicheskaya St., 194021 St. Petersburg (Russian Federation)

2014-02-17T23:59:59.000Z

416

START-GAP3/DLC3 is a GAP for RhoA and Cdc42 and is localized in focal adhesions regulating cell morphology  

SciTech Connect (OSTI)

In the human genome there are three genes encoding RhoGAPs that contain the START (steroidogenic acute regulatory protein (StAR)-related lipid transfer)-domain. START-GAP3/DLC3 is a tumor suppressor gene similar to two other human START-GAPs known as DLC1 or DLC2. Although expression of START-GAP3/DLC3 inhibits the proliferation of cancer cells, its molecular function is not well understood. In this study we carried out biochemical characterization of START-GAP3/DLC3, and explored the effects of its expression on cell morphology and intracellular localization. We found that START-GAP3/DLC3 serves as a stimulator of PLC{delta}1 and as a GAP for both RhoA and Cdc42 in vitro. Moreover, we found that the GAP activity is responsible for morphological changes. The intracellular localization of endogenous START-GAP3/DLC3 was explored by immunocytochemistry and was revealed in focal adhesions. These results indicate that START-GAP3/DLC3 has characteristics similar to other START-GAPs and the START-GAP family seems to share common characteristics.

Kawai, Katsuhisa; Kiyota, Minoru; Seike, Junichi; Deki, Yuko [Graduate School of Life Science, University of Hyogo, Harima Science Garden City, Hyogo-ken 678-1297 (Japan); Yagisawa, Hitoshi [Graduate School of Life Science, University of Hyogo, Harima Science Garden City, Hyogo-ken 678-1297 (Japan)], E-mail: yagisawa@sci.u-hyogo.ac.jp

2007-12-28T23:59:59.000Z

417

Imaging spectrometer wide field catadioptric design  

DOE Patents [OSTI]

A wide field catadioptric imaging spectrometer with an immersive diffraction grating that compensates optical distortions. The catadioptric design has zero Petzval field curvature. The imaging spectrometer comprises an entrance slit for transmitting light, a system with a catadioptric lens and a dioptric lens for receiving the light and directing the light, an immersion grating, and a detector array. The entrance slit, the system for receiving the light, the immersion grating, and the detector array are positioned wherein the entrance slit transmits light to the system for receiving the light and the system for receiving the light directs the light to the immersion grating and the immersion grating receives the light and directs the light through the system for receiving the light to the detector array.

Chrisp; Michael P. (Danville, CA)

2008-08-19T23:59:59.000Z

418

Plant Wide Assessment for SIFCO Industries, Inc.  

SciTech Connect (OSTI)

Sifco Industries carreid out a plant wide energy assessment under a collaborative program with the U.S. Department of Energy during October 2004 to September 2005. During the year, personnel from EIS, E3M, DPS, BuyCastings.Com, and Sifco plant facilities and maintenance personnel, as a team collected energy use, construction, process, equipment and operational information about the plant. Based on this information, the team identified 13 energy savings opportunities. Near term savings opportunities have a total potential savings of about $1,329,000 per year and a combined simple payback of about 11 months. Implementation of these recommendations would reduce CO2 emissions by about 16,000,000 pounds per year, which would reduce overall plant CO2 emissions by about 45%. These totals do not include another $830,000 per year in potential savings with an estimated 9-month payback, from converting the forging hammers from steam to compressed air.

Kelly Kissock, Arvind Thekdi et. al.

2005-07-06T23:59:59.000Z

419

Wide range radioactive gas concentration detector  

DOE Patents [OSTI]

A wide range radioactive gas concentration detector and monitor which is capable of measuring radioactive gas concentrations over a range of eight orders of magnitude. The device of the present invention is designed to have an ionization chamber which is sufficiently small to give a fast response time for measuring radioactive gases but sufficiently large to provide accurate readings at low concentration levels. Closely spaced parallel plate grids provide a uniform electric field in the active region to improve the accuracy of measurements and reduce ion migration time so as to virtually eliminate errors due to ion recombination. The parallel plate grids are fabricated with a minimal surface area to reduce the effects of contamination resulting from absorption of contaminating materials on the surface of the grids. Additionally, the ionization chamber wall is spaced a sufficient distance from the active region of the ionization chamber to minimize contamination effects.

Anderson, David F. (Los Alamos, NM)

1984-01-01T23:59:59.000Z

420

The CSU Graduation Initiative Closing the Achievement Gap  

E-Print Network [OSTI]

Graduation Initiative is part of the nationwide Access to Success project of the National Association to Graduation 7 #12;Tracking and Reporting Consistent evaluation of project results is a critical componentThe CSU Graduation Initiative Closing the Achievement Gap Executive Vice Chancellor Jeri Echeverria

Su, Xiao

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421

"Charter and Code" Gap Analysis ANALYSIS FOR NORWAY  

E-Print Network [OSTI]

"Charter and Code" ­ Gap Analysis ANALYSIS FOR NORWAY The European Charter for Researchers: Acceptable. The principle of research freedom is well-established in Norway. The committee refers for Research Ethics in Norway. #12;In recent years, issues of research ethics have received increasing

Johansen, Tom Henning

422

Topology of Local Health Officials' Advice Networks: Mind the Gaps  

E-Print Network [OSTI]

, evidence-based programs, and service delivery, and health care reform are innovations Author AffiliationsTopology of Local Health Officials' Advice Networks: Mind the Gaps Jacqueline Merrill, RN, MPH: To determine how a health officials' advice network might contribute to a high-performing public health systems

Sadeh, Norman M.

423

Abstract Local Reasoning for Concurrent Libraries: Mind the Gap  

E-Print Network [OSTI]

considerable work on combining lo- cal reasoning with abstraction. There are two main approaches. One approach, truly abstract reasoning of a tree module (such as DOM) works with predicates based on connecting treeMFPS 2014 Abstract Local Reasoning for Concurrent Libraries: Mind the Gap Philippa Gardner, Azalea

Gardner, Philippa

424

BRIDGING THE GAP BETWEEN BUILDING SCIENCE AND DESIGN STUDIOS  

E-Print Network [OSTI]

in the building industry and, to be effective, they need to be integrated into architectural design from, there is a lack of courses that allow for integrated building design through consideration of multiple performanceBRIDGING THE GAP BETWEEN BUILDING SCIENCE AND DESIGN STUDIOS KONSTANTINOS PAPAMICHAEL AND VINEETA

425

Thermal resistance gaps for solid breeder blankets using packed beds  

SciTech Connect (OSTI)

The main design features of a new concept for solid breeder blanket thermal resistance gaps are described and analysis is shown for the blanket thermal characteristics. The effective thermal conductivity of a helium-beryllium packed bed configuration is studied, including the effect of a purge stream. Possible applications of this concept to ITER blanket designs are stressed.

Gorbis, Z.R.; Raffray, A.R.; Tillack, M.S.; Abdou, M.A.

1989-03-01T23:59:59.000Z

426

High Temperature, High Voltage Fully Integrated Gate Driver Circuit  

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

temperature gate drive is being developed for use with future wide band gap (silicon carbide and gallium nitride) switching devices. * Universal drive that is capable of driving...

427

Low Frequency Noise in Nano-Devices  

E-Print Network [OSTI]

device quality, reliability and the degradation processes. The generation- recombination noise which. His current research interests include low frequency noise, wide-band-gap semiconductors, UV light

428

Electronic properties and reliability of the silicon dioxide / silicon carbide interface.  

E-Print Network [OSTI]

??Silicon carbide has been preferred over other wide band-gap semiconductors for high power applications because of its unique ability to grow a thermal oxide, challenges… (more)

Rozen, John

2008-01-01T23:59:59.000Z

429

Demonstration of dual-band infrared thermal imaging for bridge inspection. Phase II, final report  

SciTech Connect (OSTI)

Developing and implementing methods of effective bridge rehabilitation is a major issue for the Federal Highway Administration (FHWA). The nation spends $5 billion annually to replace, rehabilitate or construct new bridges. According to the National Bridge Inventory, over 100,000 U.S. bridges are structurally deficient. About 40,000 of these bridges have advanced deck deterioration. The most common causes of serious deck deterioration is delamination. Delaminations result when steel reinforcements within the bridge deck corrode, creating gaps that separate the concrete into layers. A reliable inspection technology, capable of identifying delaminations, would represent a power new tool in bridge maintenance. To date, most bridge inspections rely on human interpretation of surface visual features of chain dragging. These methods are slow, disruptive, unreliable and raise serious safety concerns. Infrared thermal imaging detects subsurface delaminations and surface clutter, which is introduced by foreign material on the roadway. Typically, foreign material which is not always evident on a video tape image, produces a unique IR reflectance background unlike the thermal response of a subsurface delamination. Lawrence Livermore National Laboratory (LLNL) uses dual-band infrared (DBIR) thermal imaging to identify and remove nonthermal IR reflectance backgrounds from foreign material on the roadway. DBIR methods improve the performance of IR thermal imaging by a factor of ten, compared to single-band infrared (SBIR) methods. DBIR thermal imaging allows precise temperature measurement to reliably locate bridge deck delaminations and remove wavelength-dependent emissivity variations due to foreign material on the roadway.

Durbin, P.F.; Del Grande, N.K.; Schaich, P.C.

1996-03-01T23:59:59.000Z

430

Eastern Band of Cherokee Strategic Energy Plan  

SciTech Connect (OSTI)

The Eastern Band of Cherokee Indians was awarded a grant under the U.S. Department of Energy Tribal Energy Program (TEP) to develop a Tribal Strategic Energy Plan (SEP). The grant, awarded under the “First Steps” phase of the TEP, supported the development of a SEP that integrates with the Tribe’s plans for economic development, preservation of natural resources and the environment, and perpetuation of Tribal heritage and culture. The Tribe formed an Energy Committee consisting of members from various departments within the Tribal government. This committee, together with its consultant, the South Carolina Institute for Energy Studies, performed the following activities: • Develop the Tribe’s energy goals and objectives • Establish the Tribe’s current energy usage • Identify available renewable energy and energy efficiency options • Assess the available options versus the goals and objectives • Create an action plan for the selected options

Souther Carolina Institute of energy Studies-Robert Leitner

2009-01-30T23:59:59.000Z

431

Template strand scrunching during DNA gap repair synthesis by human polymerase [lamda  

SciTech Connect (OSTI)

Family X polymerases such as DNA polymerase {lambda}(Pol {lambda}) are well suited for filling short gaps during DNA repair because they simultaneously bind both the 5{prime} and 3{prime} ends of short gaps. DNA binding and gap filling are well characterized for 1-nucleotide (nt) gaps, but the location of yet-to-be-copied template nucleotides in longer gaps is unknown. Here we present crystal structures revealing that, when bound to a 2-nt gap, Pol {lambda} scrunches the template strand and binds the additional uncopied template base in an extrahelical position within a binding pocket that comprises three conserved amino acids. Replacing these amino acids with alanine results in less processive gap filling and less efficient NHEJ when 2-nt gaps are involved. Thus, akin to scrunching by RNA polymerase during transcription initiation, scrunching occurs during gap filling DNA synthesis associated with DNA repair.

Garcia-Diaz, Miguel; Bebenek, Katarzyna; Larrea, Andres A.; Havener, Jody M.; Perera, Lalith; Krahn, Joseph M.; Pedersen, Lars C.; Ramsden, Dale A.; Kunkel, Thomas A.; (NIH); (UNC)

2009-09-25T23:59:59.000Z

432

An alternative route for efficient optical indirect-gap excitation in Ge  

SciTech Connect (OSTI)

We explored optical excitation pathways in the multivalley semiconductor Ge in an attempt to expedite selective electron injection into the indirect L-band-edge. An off-peak resonant excitation route was developed, which offers the pumping efficiency outperforming the phonon-assisted near-indirect-edge absorption by more than six orders of magnitude. The valley selectivity results from the intra-valley relaxation that separates electrons and holes in momentum space following excitation. Fortuitously, the widely used green laser, 532?nm, is found to be nearly ideally suited to the efficient L-valley-selective excitation in Ge. Such valley-specific pumping may help clarify the otherwise complicated electron dynamics involving intervalley processes.

Sakamoto, Tetsuya; Hayashi, Shuhei; Fukatsu, Susumu, E-mail: cfkatz@mail.ecc.u-tokyo.ac.jp [Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153-8902 (Japan); Yasutake, Yuhsuke [Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153-8902 (Japan); PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan)

2014-07-28T23:59:59.000Z

433

Smoothness of the Gap Function in the BCS-Bogoliubov Theory of Superconductivity  

E-Print Network [OSTI]

We deal with the gap equation in the BCS-Bogoliubov theory of superconductivity, where the gap function is a function of the temperature $T$ only. We show that the squared gap function is of class $C^2$ on the closed interval $[\\,0,\\,T_c\\,]$. Here, $T_c$ stands for the transition temperature. Furthermore, we show that the gap function is monotonically decreasing on $[0,\\,T_c]$ and obtain the behavior of the gap function at $T=T_c$. We mathematically point out some more properties of the gap function.

Shuji Watanabe

2010-06-07T23:59:59.000Z

434

Wide Area Security Region Final Report  

SciTech Connect (OSTI)

This report develops innovative and efficient methodologies and practical procedures to determine the wide-area security region of a power system, which take into consideration all types of system constraints including thermal, voltage, voltage stability, transient and potentially oscillatory stability limits in the system. The approach expands the idea of transmission system nomograms to a multidimensional case, involving multiple system limits and parameters such as transmission path constraints, zonal generation or load, etc., considered concurrently. The security region boundary is represented using its piecewise approximation with the help of linear inequalities (so called hyperplanes) in a multi-dimensional space, consisting of system parameters that are critical for security analyses. The goal of this approximation is to find a minimum set of hyperplanes that describe the boundary with a given accuracy. Methodologies are also developed to use the security hyperplanes, pre-calculated offline, to determine system security margins in real-time system operations, to identify weak elements in the system, and to calculate key contributing factors and sensitivities to determine the best system controls in real time and to assist in developing remedial actions and transmission system enhancements offline . A prototype program that automates the simulation procedures used to build the set of security hyperplanes has also been developed. The program makes it convenient to update the set of security hyperplanes necessitated by changes in system configurations. A prototype operational tool that uses the security hyperplanes to assess security margins and to calculate optimal control directions in real time has been built to demonstrate the project success. Numerical simulations have been conducted using the full-size Western Electricity Coordinating Council (WECC) system model, and they clearly demonstrated the feasibility and the effectiveness of the developed technology. Recommendations for the future work have also been formulated.

Makarov, Yuri V.; Lu, Shuai; Guo, Xinxin; Gronquist, James; Du, Pengwei; Nguyen, Tony B.; Burns, J. W.

2010-03-31T23:59:59.000Z

435

Properties of the rotational bands in {sup 161}Er  

SciTech Connect (OSTI)

High-spin states in {sup 161}Er have been studied experimentally using the {sup 150}Nd({sup 16}O,5n) reaction at a beam energy of 86 MeV. The 5/2{sup +}[642], 3/2{sup -}[521], and 11/2{sup -}[505] bands are extended up to high-spin states, and particularly the {alpha}=-1/2 branch of the ground state 3/2{sup -}[521] band is revised significantly. The relatively enhanced E1 transitions from the 3/2{sup -}[521] band to the 5/2{sup +}[642] band are observed. The band properties are analyzed within the framework of a triaxial particle-rotor model, and near-prolate shape and triaxial deformation are proposed to the 3/2{sup -}[521] and 5/2{sup +}[642] bands, respectively. Signature inversion occurs in the 3/2{sup -}[521] band after the band crossing in {sup 161}Er, and the systematics of the signature inversion associated with the 3/2{sup -}[521] configuration are discussed. By analyzing the properties of the relatively enhanced E1 transitions, it is found that the R(E1/E2) values show angular momentum dependence before the band crossing, and these enhanced E1 transitions could be attributed to octupole softness.

Chen, L.; Zhou, X. H.; Wang, S. T.; Zhang, N. T.; Zhou, H. B.; Li, G. S.; Wang, H. X.; Ding, B. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Y. H.; Zheng, Y.; Liu, M. L.; Ma, F.; Fang, Y. D.; Hua, W.; Guo, S.; Qiang, Y. H.; Lei, X. G.; Guo, Y. X. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhu, L. H.; Wu, X. G. [China Institute of Atomic Energy, Beijing 102413 (China)

2011-03-15T23:59:59.000Z

436

Engineering the Electronic Band Structure for Multiband Solar Cells  

SciTech Connect (OSTI)

Using the unique features of the electronic band structure of GaNxAs1-x alloys, we have designed, fabricated and tested a multiband photovoltaic device. The device demonstrates an optical activity of three energy bands that absorb, and convert into electrical current, the crucial part of the solar spectrum. The performance of the device and measurements of electroluminescence, quantum efficiency and photomodulated reflectivity are analyzed in terms of the Band Anticrossing model of the electronic structure of highly mismatched alloys. The results demonstrate the feasibility of using highly mismatched alloys to engineer the semiconductor energy band structure for specific device applications.

Lopez, N.; Reichertz, L.A.; Yu, K.M.; Campman, K.; Walukiewicz, W.

2010-07-12T23:59:59.000Z

437

Air-Gap Convection in a Switched Reluctance Machine  

E-Print Network [OSTI]

Switched reluctance machines (SRMs) have recently become popular in the automotive market as they are a good alternative to the permanent magnet machines commonly employed for an electric powertrain. Lumped parameter thermal networks are usually used for thermal analysis of motors due to their low computational cost and relatively accurate results. A critical aspect to be modelled is the rotor-stator air-gap heat transfer, and this is particularly challenging in an SRM due to the salient pole geometry. This work presents firstly a review of the literature including the most relevant correlations for this geometry, and secondly, numerical CFD simulations of air-gap heat transfer for a typical configuration. A new correlation has been derived: $\\mathbf{Nu=0.181\\ Ta_m^{0.207}}$

Romanazzi, Pietro

2015-01-01T23:59:59.000Z

438

The imaginary part of the gap function in color superconductivity  

E-Print Network [OSTI]

We clarify general properties of the energy gap regarding its functional dependence on the energy-momentum dictated by the invariance under a space inversion or a time reversal. Then we derive perturbatively the equation of the imaginary part of the gap function for dense QCD in weak coupling and generalize our results from 2SC case to CFL case. We confirm that the imaginary part is down by $g$ relative to the real part in weak coupling. The numerical results show that, up to the leading order, the imaginary part is no larger than one MeV at extremely large densities and can be as large as several MeV the densities are of physical interest.

Bo Feng; Defu Hou; Jiarong Li; Hai-cang Ren

2006-09-16T23:59:59.000Z

439

Spark gap switch system with condensable dielectric gas  

DOE Patents [OSTI]

A spark gap switch system is disclosed which is capable of operating at a high pulse rate comprising an insulated switch housing having a purging gas entrance port and a gas exit port, a pair of spaced apart electrodes each having one end thereof within the housing and defining a spark gap therebetween, an easily condensable and preferably low molecular weight insulating gas flowing through the switch housing from the housing, a heat exchanger/condenser for condensing the insulating gas after it exits from the housing, a pump for recirculating the condensed insulating gas as a liquid back to the housing, and a heater exchanger/evaporator to vaporize at least a portion of the condensed insulating gas back into a vapor prior to flowing the insulating gas back into the housing.

Thayer, III, William J. (Kent, WA)

1991-01-01T23:59:59.000Z

440

Valley pair qubits in double quantum dots of gapped graphene  

E-Print Network [OSTI]

The rise of graphene opens a new door to qubit implementation, as discussed in the recent proposal of valley pair qubits in double quantum dots of gapped graphene (Wu et al., arXiv: 1104.0443 [cond-mat.mes-hall]). The work here presents the comprehensive theory underlying the proposal. It discusses the interaction of electrons with external magnetic and electric fields in such structures. Specifically, it examines a strong, unique mechanism, i.e., the analogue of the 1st-order relativistic effect in gapped graphene. This mechanism is state mixing free and allows, together with the electrically tunable exchange coupling, a fast, all-electric manipulation of qubits via electric gates, in the time scale of ns. The work also looks into the issue of fault tolerance in a typical case, yielding at 10oK a long qubit coherence time (~O(ms)).

G. Y. Wu; N. -Y. Lue; L. Chang

2011-07-03T23:59:59.000Z

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


441

Damping of lower hybrid waves in large spectral gap configurations  

SciTech Connect (OSTI)

Extensive experimental data support reliable power deposition and current drive by lower-hybrid (LH) waves in conditions where a large spectral gap exists between the nominal parallel index of refraction prescribed by the antenna characteristics and phasing, and that required for significant Landau damping to take place. We argue that only a significant modification of the initial spectrum at the plasma edge could explain experimental observations. Based on this assumption, a new prescription for reliable simulations of LH current drive using ray-tracing and Fokker-Planck modelling is proposed. A remarkable agreement between experimental observations in the Tore Supra tokamak and simulations is obtained for relevant parametric scans, including electron density and LH waveguide phasing. In an effort to investigate the possible role of fluctuations, it is shown that the spectral gap can be bridged dynamically in the presence of a fluctuating LH spectrum.

Decker, J.; Peysson, Y.; Artaud, J.-F.; Nilsson, E.; Ekedahl, A.; Goniche, M.; Hillairet, J.; Mazon, D. [CEA, IRFM, F-13108 Saint Paul lez Durance (France)

2014-02-12T23:59:59.000Z

442

Entanglement vs. gap for one-dimensional spin systems  

SciTech Connect (OSTI)

We study the relationship between entanglement and spectral gap for local Hamiltonians in one dimension. The area law for a one-dimensional system states that for the ground state, the entanglement of any interval is upper-bounded by a constant independent of the size of the interval. However, the possible dependence of the upper bound on the spectral gap {Delta} is not known, as the best known general upper bound is asymptotically much larger than the largest possible entropy of any model system previously constructed for small {Delta}. To help resolve this asymptotic behavior, we construct a family of one-dimensional local systems for which some intervals have entanglement entropy which is polynomial in 1/{Delta}, whereas previously studied systems had the entropy of all intervals bounded by a constant times log(1/{Delta}).

Hastings, Matthew [Los Alamos National Laboratory; Aharonov, Dorit [HEBREW UNIV; Gottesman, Daniel [PERIMETER INSTITUTE

2008-01-01T23:59:59.000Z

443

Fully Integrated Frequency and Phase Generation for a 6-18GHz Tunable Multi-Band Phased-Array Receiver in CMOS  

E-Print Network [OSTI]

control, phase locked loops, phase noise, phased arrays, radio receivers I. INTRODUCTION Very large-scale phased-arrays covering a wide range of frequencies can provide exciting new opportunities for increasedFully Integrated Frequency and Phase Generation for a 6-18GHz Tunable Multi-Band Phased

Hajimiri, Ali

444

Bridge Health Insurance Options ief gap in health  

E-Print Network [OSTI]

limitations to bear in mind: n denied health care coverage, you almost certainly won't qualify y at the end-800-304-0372 www.anthem.com and click on visitor and click on state. United Health Care at 1-888-545-5205 or visitBridge Health Insurance Options ief gap in health of coverage became seriously hurt or ill. That

445

Diffuse interstellar bands in M33  

E-Print Network [OSTI]

We present the first sample of diffuse interstellar bands (DIBs) in the nearby galaxy M33. Studying DIBs in other galaxies allows the behaviour of the carriers to be examined under interstellar conditions which can be quite different from those of the Milky Way, and to determine which DIB properties can be used as reliable probes of extragalactic interstellar media. Multi-object spectroscopy of 43 stars in M33 has been performed using Keck/DEIMOS. The stellar spectral types were determined and combined with literature photometry to determine the M33 reddenings E(B-V)_M33. Equivalent widths or upper limits have been measured for the {\\lambda}5780 DIB towards each star. DIBs were detected towards 20 stars, demonstrating that their carriers are abundant in M33. The relationship with reddening is found to be at the upper end of the range observed in the Milky Way. The line of sight towards one star has an unusually strong ratio of DIB equivalent width to E(B-V)_M33, and a total of seven DIBs were detected towards...

Smith, Keith T; Evans, Christopher J; Cox, Nick L J; Sarre, Peter J

2013-01-01T23:59:59.000Z

446

ECONOMIC IMPACTS OF A WIDE AREA RELEASE OF ANTHRAX  

E-Print Network [OSTI]

ECONOMIC IMPACTS OF A WIDE AREA RELEASE OF ANTHRAX May 2009 Prepared Regional Technology Center for Homeland Security Economic Impacts of a Wide Area Release of Anthrax KS .................................................................................................................................................. 1 Categories of Economic Impacts

447

Advanced applications in wide-area impedance sensing  

E-Print Network [OSTI]

In this thesis a wide-area impedance sensor used in hyperspectral imaging for a wide variety of applications is presented. Building on previous work, this sensor is decoupled from fluorescent lamps and thus is used to ...

George, Elizabeth C. (Elizabeth Christine)

2014-01-01T23:59:59.000Z

448

Benefits of Site-wide NEPA National Environmental Policy Act...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Benefits of Site-wide NEPA National Environmental Policy Act Review (1994) Benefits of Site-wide NEPA National Environmental Policy Act Review (1994) The purpose of this guidance...

449

Of horseshoes and heliotropes: Dynamics of dust in the Encke Gap M.M. Hedman a,  

E-Print Network [OSTI]

Of horseshoes and heliotropes: Dynamics of dust in the Encke Gap M.M. Hedman a, , J.A. Burns a located within the Cassini Division's Laplace Gap demonstrates ``heliotropic'' behavior: its geometric

Hamilton, Douglas P.

450

Variation of treefall gap characteristics in an East Texas bottomland hardwood forest: effects of microtopography  

E-Print Network [OSTI]

Treefall gaps, formed as a result of small-scale disturbances, allow seedling recruitment and growth in late-successional forests. Many factors contribute to gap regime heterogeneity within and among forest stands, including wind and fire patterns...

Almquist, Benjamin Eric

1998-01-01T23:59:59.000Z

451

Hydraulically controlled magnetic bougienage for correction of long-gap esophageal atresia  

E-Print Network [OSTI]

About one in 4000 babies in the United States is born with their esophageal disconnected and separated by a gap, which is called esophageal atresia. Esophageal atresia with a relatively short gap can be directly corrected ...

Noh, Minkyun

2014-01-01T23:59:59.000Z

452

Fact #837: September 8, Gap between Net Imports and Total Imports...  

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

7: September 8, Gap between Net Imports and Total Imports of Petroleum is Widening Fact 837: September 8, Gap between Net Imports and Total Imports of Petroleum is Widening Net...

453

Controlling electrode gap during vacuum arc remelting at low melting current  

DOE Patents [OSTI]

An apparatus and method are disclosed for controlling electrode gap in a vacuum arc remelting furnace, particularly at low melting currents. Spectrographic analysis is performed of the metal vapor plasma, from which estimates of electrode gap are derived. 5 figs.

Williamson, R.L.; Zanner, F.J.; Grose, S.M.

1997-04-15T23:59:59.000Z

454

Controlling electrode gap during vacuum arc remelting at low melting current  

DOE Patents [OSTI]

An apparatus and method for controlling electrode gap in a vacuum arc remelting furnace, particularly at low melting currents. Spectrographic analysis is performed of the metal vapor plasma, from which estimates of electrode gap are derived.

Williamson, Rodney L. (Albuquerque, NM); Zanner, Frank J. (Sandia Park, NM); Grose, Stephen M. (Glenwood, WV)

1997-01-01T23:59:59.000Z

455

World Wide Web Internet and Web Information Systems  

E-Print Network [OSTI]

1 23 World Wide Web Internet and Web Information Systems ISSN 1386-145X World Wide Web DOI 10's request, provided it is not made publicly available until 12 months after publication. #12;World Wide Web worlds. Its detection is a typical use case of the broad-based Wisdom Web of Things (W2T) methodology

Cao, Longbing

456

A multi-band phase-locked loop frequency synthesizer  

E-Print Network [OSTI]

A phase-locked loop (PLL) frequency synthesizer suitable for multi-band transceivers is proposed. The multi-band PLL frequency synthesizer uses a switched tuning voltage- controlled oscillator (VCO) that covers a frequency range of 111 to 297MHz...

Palermo, Samuel Michael

1999-01-01T23:59:59.000Z

457

Intermediate Band Properties of Femtosecond-Laser Hyperdoped Silicon  

E-Print Network [OSTI]

. The high concentration of dopants forms an intermediate band (IB), instead of discrete energy levels exhibits broad-band light absorption to wavelengths deep below the corresponding bandgap energy of silicon) using secondary ion mass spectrometry. By varying the pressure of SF6, we find that the surface adsorbed

Mazur, Eric

458

BAND STRUCTURE AND OPTICAL PROPERTIES OF MAGNESIUM FLUORIDE  

E-Print Network [OSTI]

595 BAND STRUCTURE AND OPTICAL PROPERTIES OF MAGNESIUM FLUORIDE C. JOUANIN, J. P. ALBERT and C'autres transitions expéri- mentales. Abstract. 2014 The electronic band structure of magnesium fluoride is calculated, only some qualitative investigations exist for the calcium and magnesium fluorides [1, 2]. This lack

Paris-Sud XI, Université de

459

absorption band substructure: Topics by E-print Network  

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

absorption band substructure First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 THE ABSORPTION BAND EDGE...

460

THE INVERSE OF A SEMI-INFINITE SYMMETRIC BANDED MATRIX  

E-Print Network [OSTI]

algorithm 3]. The eigen- values and eigen-vectors for the nite symmetric tridiagonal case were obtainedTHE INVERSE OF A SEMI-INFINITE SYMMETRIC BANDED MATRIX D. A. LAVISy , B. W. SOUTHERNz and I. F a method for obtaining an analytic form for a class of sym- metric semi-in nite banded matrices, which are

Lavis, David

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


461

Erratum to ``How should gaps be treated in parsimony? A comparison of approaches using simulation"  

E-Print Network [OSTI]

Erratum Erratum to ``How should gaps be treated in parsimony? A comparison of approaches using)]. The three comparisons for treating gaps as unknown, fifth state character, and Simple Indel Coding are shownTrueTree TAA Fig. 3. Moving average lines of treating gaps as unknown, fifth state, and Simple Indel Coding

Rosenberg, Michael S.

462

OIKOS 101: 499504, 2003 Do seedlings in gaps interact? A field test of assumptions in ESS  

E-Print Network [OSTI]

OIKOS 101: 499­504, 2003 Do seedlings in gaps interact? A field test of assumptions in ESS seed seedlings in gaps interact? A field test of assumptions in ESS seed size models. ­ Oikos 101: 499­504. ESS for the occupancy of `safe sites' or vegetation gaps. If mortality rates are high and/or frequency-independent, ESS

Silvertown, Jonathan

463

The Quasi-Distributed Gap Technique for Planar Inductors-Design Guidelines  

E-Print Network [OSTI]

The Quasi-Distributed Gap Technique for Planar Inductors-Design Guidelines Jiankun Hu C. R The Quasi-Distributed Gap Technique for Planar Inductors: Design Guidelines Jiankun Hu Charles R. Sullivan of low-permeability magnetic material to form a uniformly distributed gap can facilitate the design

464

Penetration of plasma into the wafer-focus ring gap in capacitively coupled plasmas  

E-Print Network [OSTI]

Penetration of plasma into the wafer-focus ring gap in capacitively coupled plasmas Natalia Y of capacitively coupled plasma reactors with a wafer-focus ring gap. The penetration of plasma generated species i.e., ions and radicals into the wafer-focus ring gap is discussed. We found that the penetration of plasma

Kushner, Mark

465

An Abelian Ward identity and the vertex corrections to the color superconducting gap  

E-Print Network [OSTI]

We derive an Abelian-like Ward identity in color superconducting phase and calculate vertex corrections to the color superconducting gap. Making use of the Ward identity, we show that subleading order contributions to the gap from vertices are absent for gapped excitations.

Hao-jie Xu; Qun Wang

2008-10-13T23:59:59.000Z

466

THE DEVIL’S STAIRCASE DIMENSIONS AND MEASURE-THEORETICAL ENTROPY OF MAPS WITH HORIZONTAL GAP  

E-Print Network [OSTI]

Abstract. This work elucidates the measure-theoretical entropy and dimensions of a unimodal map with a horizontal gap. The measure-theoretical entropy and dimensions of the Ft (which is defined later)are shown to form a devil’s staircase structure with respect to the gap size t. Pesin’s formula for gap maps is also considered. 1.

Jung-chao Ban; Song-sun Lin

467

Broad band X-ray spectrum of KS 1947+300 with BeppoSAX  

E-Print Network [OSTI]

We present results obtained from three BeppoSAX observations of the accretion-powered transient X-ray pulsar KS 1947+300 carried out during the declining phase of its 2000 November -- 2001 June outburst. A detailed spectral study of KS 1947+300 across a wide X-ray band (0.1--100.0 keV) is attempted for the first time here. Timing analysis of the data clearly shows a 18.7 s pulsation in the X-ray light curves in the above energy band. The pulse profile of KS 1947+300 is characterized by a broad peak with sharp rise followed by a narrow dip. The dip in the pulse profile shows a very strong energy dependence. Broad-band pulse-phase-averaged spectroscopy obtained with three of the BeppoSAX instruments shows that the energy spectrum in the 0.1--100 keV energy band has three components, a Comptonized component, a ~0.6 keV blackbody component, and a narrow and weak iron emission line at 6.7 keV with a low column density of material in the line of sight. We place an upper limit on the equivalent width of the iron K_\\alpha line at 6.4 keV of ~13 eV (for a width of 100 eV). Assuming a spherical blackbody emitting region and the distance of the source to be 10 kpc, the radius of the emitting region is found to be in the range of 14--22 km, which rules out the inner accretion disk as the soft X-ray emitting region.

S. Naik; P. J. Callanan; B. Paul; T. Dotani

2006-05-01T23:59:59.000Z

468

Highly deformed high-spin band in {sup 125}I  

SciTech Connect (OSTI)

High-spin states in {sup 125}I have been investigated using the reaction {sup 82}Se({sup 48}Ca, p4n) at a beam energy of 200 MeV and {gamma}-ray coincidence events were detected using the Gammasphere spectrometer. A deformed rotational band, extending up to I{sup {pi}=}95/2{sup -}, was observed for the first time in a heavier odd-A iodine nucleus. The characteristics of the band are very similar to those of the highly deformed bands observed recently in neighboring nuclei and it is essentially identical to one of the previously known bands in {sup 126}Xe. The experimental results are compared to cranked Nilsson-Strutinsky calculations and possible configurations for the band are discussed.

Singh, Purnima; Nag, Somnath; Singh, A. K.; Ragnarsson, I.; Huebel, H.; Al-Khatib, A.; Bringel, P.; Engelhardt, C.; Neusser-Neffgen, A.; Hagemann, G. B.; Hansen, C. R.; Herskind, B.; Sletten, G.; Bracco, A.; Benzoni, G.; Camera, F.; Fallon, P.; Clark, R. M.; Carpenter, M. P.; Janssens, R. V. F. [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur, IN-721302 (India); Department of Mathematical Physics, Lund Institute of Technology, Box 118, S-221 Lund (Sweden); Helmholtz-Institut fuer Strahlen- und Kernphysik, Universitaet Bonn, Nussallee 14-16, D-53115 Bonn (Germany); Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen O (Denmark); Dipartimento di Fisica, Universita di Milano and INFN, Sezione di Milano, I-20133 Milano (Italy); Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854 (United States); Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2011-08-15T23:59:59.000Z

469

Aqueous Transition Metal Cations as Impurities in a Wide Gap Oxide: The Cu^2+/Cu^1+ and Ag^2+/Ag^1+ Redox Couples Revisited  

E-Print Network [OSTI]

of 10ps. The longitudinal relaxation is more than a magnitude faster. Results and analysis Gas-phase Table 1 lists the calculated M-O bond lengths in the four gas-phase complexes we have investigated (see fig. 1). One can see that for the same number... containing a fraction of Hartree-Fock exchange. These calculations make use of recent progress in DFTMD technology enabling us to include sp core polarization and Hartree-Fock exchange in condensed phase model systems. Keywords Aqueous redox chemistry...

Liu, Xiandong; Cheng, Jun; Sprik, Michiel

2014-11-11T23:59:59.000Z

470

A non-uniform three-gap buncher cavity with suppression of transverse-electromagnetic mode leakage in the triaxial klystron amplifier  

SciTech Connect (OSTI)

The triaxial klystron amplifier is an efficient high power relativistic klystron amplifier operating at high frequencies due to its coaxial structure with large radius. However, the coaxial structures result in coupling problems among the cavities as the TEM mode is not cut-off in the coaxial tube. Therefore, the suppression of the TEM mode leakage, especially the leakage from the buncher cavity to the input cavity, is crucial in the design of a triaxial klystron amplifier. In this paper, a non-uniform three-gap buncher cavity is proposed to suppress the TEM mode leakage. The cold cavity analysis shows that the non-uniform three-gap buncher cavity can significantly suppress the TEM mode generation compared to a uniform three-gap buncher cavity. Particle-in-cell simulation shows that the power leakage to the input cavity is less than 1.5‰ of the negative power in the buncher cavity and the buncher cavity can efficiently modulate an intense relativistic electron beam free of self-oscillations. A fundamental current modulation depth of 117% is achieved by employing the proposed non-uniform buncher cavity into an X-band triaxial amplifier, which results in the high efficiency generation of high power microwave.

Qi, Zumin; Zhang, Jun, E-mail: zhangjun-nudt@126.com; Zhong, Huihuang; Zhu, Danni; Qiu, Yongfeng [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha, Hunan 410073 (China)] [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha, Hunan 410073 (China)

2014-01-15T23:59:59.000Z

471

uvby-Hbeta CCD photometry and membership segregation of the open cluster NGC 2548; Gaps in the Main Sequence of open clusters  

E-Print Network [OSTI]

Deep CCD photometry in the uvby-Hbeta intermediate-band system is presented for the cluster NGC 2548 (M 48). A complete membership analysis based on astrometric and photometric criteria is applied. The photometric analysis of a selected sample of stars yields a reddening value of E(b-y)=0.06\\pm0.03, a distance modulus of V_0-M_V=9.3\\pm0.5 (725 pc) and a metallicity of [Fe/H]= -0.24\\pm0.27. Through isochrone fitting we find an age of log t = 8.6\\pm0.1 (400 Myr). Our optical photometry and JHK from 2MASS are combined to derive effective temperatures of cluster member stars. The effective temperature distribution along the main sequence of the cluster shows several gaps. A test to study the significance of these gaps in the main sequence of the HR diagram has been applied. The method is also applied to several other open clusters (Pleiades, Hyades, NGC 1817 and M 67) to construct a sequence of metallicities and ages. The comparison of the results of each cluster gives four gaps with high significance (one of the...

Balaguer-Nuńez, L; Galadi-Enriquez, D

2004-01-01T23:59:59.000Z

472

Direct control of air gap flux in permanent magnet machines  

DOE Patents [OSTI]

A method and apparatus for field weakening in PM machines uses field weakening coils (35, 44, 45, 71, 72) to produce flux in one or more stators (34, 49, 63, 64), including a flux which counters flux normally produced in air gaps between the stator(s) (34, 49, 63, 64) and the rotor (20, 21, 41, 61) which carries the PM poles. Several modes of operation are introduced depending on the magnitude and polarity of current in the field weakening coils (35, 44, 45, 71, 72). The invention is particularly useful for, but not limited to, the electric vehicle drives and PM generators.

Hsu, John S. (Oak Ridge, TN)

2000-01-01T23:59:59.000Z

473

Low-pressure spark gap triggered by an ion diode  

DOE Patents [OSTI]

Spark gap apparatus for use as an electric switch operating at high voltage, high current and high repetition rate. Mounted inside a housing are an anode, cathode and ion plate. An ionizable fluid is pumped through the chamber of the housing. A pulse of current to the ion plate causes ions to be emitted by the ion plate, which ions move into and ionize the fluid. Electric current supplied to the anode discharges through the ionized fluid and flows to the cathode. Current stops flowing when the current source has been drained. The ionized fluid recombines into its initial dielectric ionizable state. The switch is now open and ready for another cycle.

Prono, D.S.

1982-08-31T23:59:59.000Z

474

Fermi velocity renormalization and dynamical gap generation in graphene  

E-Print Network [OSTI]

We study the renormalization of the Fermi velocity by the long-range Coulomb interactions between the charge carriers in the Dirac-cone approximation for the effective low-energy description of the electronic excitations in graphene at half filling. Solving the coupled system of Dyson-Schwinger equations for the dressing functions in the corresponding fermion propagator with various approximations for the particle-hole polarization we observe that Fermi velocity renormalization effects generally lead to a considerable increase of the critical coupling for dynamical gap generation and charge-density wave formation at the semimetal-insulator transition.

C. Popovici; C. S. Fischer; L. von Smekal

2015-01-12T23:59:59.000Z

475

FAQS Gap Analysis Qualification Card - Industrial Hygiene | Department of  

Energy Savers [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 Office of Inspector General Office of Audit|Department of Energy56Executive212-2012 June;'FAQ:Energy FAQS Gap

476

Minding the Gap Makes for More Efficient Solar Cells  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas Conchas recovery challenge fundProject8 -3EutecticMinding the Gap Makes for More

477

Bridge the Gap 2014 --Guidance for Participants Requiring Level Access This level-access route is meant to accommodate Bridge the Gap participants using  

E-Print Network [OSTI]

or there is an alternative route in to the College theough the Golden Gate. There will be a steward on hand to assist. 12Bridge the Gap 2014 -- Guidance for Participants Requiring Level Access This level-access route is meant to accommodate Bridge the Gap participants using wheelchairs, mobility scooters and pushchairs

Travis, Adrian

478

Of Horseshoes and Heliotropes: Dynamics of Dust in the Encke Gap  

E-Print Network [OSTI]

The Encke Gap is a 320-km-wide opening in Saturn's outer A ring that contains the orbit of the small moon Pan and an array of dusty features composed of particles less than 100 microns across. In particular, there are three narrow ringlets in this region that are not longitudinally homogeneous, but instead contain series of bright clumps. Using images obtained by the Cassini spacecraft, we track the motions of these clumps and demonstrate that they do not follow the predicted trajectories of isolated ring particles moving under the influence of Saturn's and Pan's gravitational fields. We also examine the orbital properties of these ringlets by comparing images taken at different longitudes and times. We find evidence that the orbits of these particles have forced eccentricities induced by solar radiation pressure. In addition, the mean radial positions of the particles in these ringlets appear to vary with local co-rotating longitude, perhaps due to the combined action of drag forces, gravitational perturbati...

Hedman, M M; Hamilton, D P; Showalter, M R

2013-01-01T23:59:59.000Z

479

Measurement of the valence band-offset in a PbSe/ZnO heterojunction by x-ray photoelectron spectroscopy  

SciTech Connect (OSTI)

A heterojunction of PbSe/ZnO has been grown by molecular beam epitaxy. X-ray photoelectron spectroscopy was used to directly measure the valence-band offset (VBO) of the heterojunction. The VBO, {Delta}E{sub V}, was determined as 2.51 {+-} 0.05 eV using the Pb 4p{sup 3/2} and Zn 2p{sup 3/2} core levels as a reference. The conduction-band offset, {Delta}E{sub C}, was, therefore, determined to be 0.59 {+-} 0.05 eV based on the above {Delta}E{sub V} value. This analysis indicates that the PbSe/ZnO heterojunction forms a type I (Straddling Gap) heterostructure.

Li Lin; Qiu Jijun; Weng Binbin; Yuan Zijian; Shi Zhisheng [School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019 (United States); Li Xiaomin; Gan Xiaoyan [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Sellers, Ian R. [Deparment of Physics, University of Oklahoma, Norman, Oklahoma 73019 (United States)

2012-12-24T23:59:59.000Z

480

USFS West Wide Programmatic Environmental Impact Statement Record...  

Open Energy Info (EERE)

Programmatic Environmental Impact Statement Record of Decision Jump to: navigation, search OpenEI Reference LibraryAdd to library Legal Document- OtherOther: USFS West Wide...

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


481

Y-12 Final Site-Wide Environmental Impact Statement Approved...  

National Nuclear Security Administration (NNSA)

Final Site-Wide Environmental Impact Statement Approved | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile...

482

EIS-0426: Site-Wide Environmental Impact Statement for Continued...  

Office of Environmental Management (EM)

Site-Wide Environmental Impact Statement for Continued Operation of the Department of Energy National Nuclear Security Administration Nevada National Security Site and Off-Site...

483

EIS-0426: Site-Wide Environmental Impact Statement for Continued...  

Energy Savers [EERE]

6: Site-Wide Environmental Impact Statement for Continued Operation of the Department of Energy National Nuclear Security Administration Nevada National Security Site and...

484

EA-1583: Final Site-wide Environmental Assessment | Department...  

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

Assessment EA-1583: Final Site-wide Environmental Assessment RMOTCNaval Petroleum Reserve No. 3 (October 2008) SUMMARY: The U.S. Departmem of Energy (DOE) is...

485

EA-1956: Site-Wide Environmental Assessment for the Divestiture...  

Energy Savers [EERE]

Assessment for the Divestiture of Rocky Mountain Oilfield Testing Center and Naval Petroleum Reserve No. 3, Natrona County, Wyoming EA-1956: Site-Wide Environmental Assessment...

486

EIS-0238: Draft Site-Wide Environmental Impact Statement  

Broader source: Energy.gov [DOE]

Draft Site-Wide Environmental Impact Statement on the Continued Operation of the Los Alamos National Laboratory, Los Alamos, New Mexico

487

A study of potential high band-gap photovoltaic materials for a two step photon intermediate technique in fission energy conversion  

SciTech Connect (OSTI)

A diamond synthesis chamber and an ion implanter have been constructed. Work has been rapidly progressing and diamond has been synthesized. There are five variables which affect the quality of diamond: (1) mass flow of methane, (2) mass flow of hydrogen, (3) filament temperature, (4) substrate temperature, and (5) substrate material. Enclosed are pictures and data of previous diamond growth experiments. Current work is focused on the conditions which produce the best quality diamond films. In this study, diamond films were deposited using a hot-filament CVD method with boron trioxide (B{sub 2}O{sub 3}) and diphosphorus pentoxide (P{sub 2}O{sub 5}) as the doping sources. P{sub 2}O{sub 5} is the only known effective phosphorus source for forming n-type semiconducting material. An RF generator has been made operation for epitaxial growth of AIN by the chemical vapor deposition method. In initial experiments with a graphite substrate, the RF generator heated the material to a temperature of 1100{degrees}C. A reactor which will use the RF generator has been built for AIN synthesis. The device should be assembled and tested by the end of August. A new process for fabricating platinum silicide photovoltaic cells has been developed. A diffused guard ring has been added to minimize leakage current. VUV to near IR capability has been developed for optical characterization. A microwave driven excimer lamp has been built and tested. Our previous work used a microwave source on an electron cyclotron heated ion source.

Not Available

1991-08-16T23:59:59.000Z

488

Narrow energy band gap gallium arsenide nitride semi-conductors and an ion-cut-synthesis method for producing the same  

DOE Patents [OSTI]

A method for forming a semi-conductor material is provided that comprises forming a donor substrate constructed of GaAs, providing a receiver substrate, implanting nitrogen into the donor substrate to form an implanted layer comprising GaAs and nitrogen. The implanted layer is bonded to the receiver substrate and annealed to form GaAsN and nitrogen micro-blisters in the implanted layer. The micro-blisters allow the implanted layer to be cleaved from the donor substrate.

Weng, Xiaojun; Goldman, Rachel S.

2006-06-06T23:59:59.000Z

489

JLMN-Journal of Laser Micro/Nanoengineering Vol. 4, No. 3, 2009 Control of Ionization Processes in High Band Gap Materials  

E-Print Network [OSTI]

of fused silica with temporally asymmetric shaped femtosecond laser pulses obtained by introducing third materials, e.g. dielectrics, ranging from industrial precision micro machining to life science de- mands [1

Kassel, Universität

490

Quantification of electronic band gap and surface states on FeS2(100) F.W. Herbert a,b  

E-Print Network [OSTI]

, which are relevant to evaluation of electrochemical processes including corrosion and solar energy-containing environments such as those encoun- tered by the oil and gas industry, where it is typically incorporated into passive corrosion films on steel structures [14]. In the following, we re- view the literature and discuss

Yildiz, Bilge

491

Specific-heat discontinuity in impure two-band superconductors  

E-Print Network [OSTI]

The Ginzburg-Landau coefficients and the jump of the specific heat are calculated for a disordered two-band superconductor. We start with the analysis of a more general case with arbitrary anisotropy. While the specific-heat discontinuity...

Mishonov, TM; Penev, ES; Indekeu, JO; Pokrovsky, Valery L.

2003-01-01T23:59:59.000Z

492

Direct observation of a dispersionless impurity band in hydrogenated graphene  

E-Print Network [OSTI]

We show with angle-resolved photoemission spectroscopy that a new energy band appears in the electronic structure of electron-doped hydrogenated monolayer graphene (H-graphene). Its occupation can be controlled with the ...

Haberer, D.

493

Global estimation of precipitation using opaque microwave bands  

E-Print Network [OSTI]

This thesis describes the use of opaque microwave bands for global estimation of precipitation rate. An algorithm was developed for estimating instantaneous precipitation rate for the Advanced Microwave Sounding Unit (AMSU) ...

Chen, Frederick Wey-Min, 1975-

2004-01-01T23:59:59.000Z

494

Phenomenological band structure model of magnetic coupling in semiconductors  

E-Print Network [OSTI]

Phenomenological band structure model of magnetic coupling in semiconductors Gustavo M. Dalpian a,1­18]. Several models have been proposed to explain the phenomena, including the phenomenological Zener

Gong, Xingao

495

angstrom extinction band: Topics by E-print Network  

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

Galactic extinction curve, which implies that the properties of dust in the extragalactic enviroment are similar to those of the Milky Way. The ratio of the total V band extinction...

496

An X-Band Gun Test Area at SLAC  

SciTech Connect (OSTI)

The X-Band Test Area (XTA) is being assembled in the NLCTA tunnel at SLAC to serve as a test facility for new RF guns. The first gun to be tested will be an upgraded version of the 5.6 cell, 200 MV/m peak field X-band gun designed at SLAC in 2003 for the Compton Scattering experiment run in ASTA. This new version includes some features implemented in 2006 on the LCLS gun such as racetrack couplers, increased mode separation and elliptical irises. These upgrades were developed in collaboration with LLNL since the same gun will be used in an injector for a LLNL Gamma-ray Source. Our beamline includes an X-band acceleration section which takes the electron beam up to 100 MeV and an electron beam measurement station. Other X-Band guns such as the UCLA Hybrid gun will be characterized at our facility.

Limborg-Deprey, C.; Adolphsen, C.; Chu, T.S.; Dunning, M.P.; Jobe, R.K.; Jongewaard, E.N.; Hast, C.; Vlieks, A.E.; Wang, F.; Walz, D.R.; /SLAC; Marsh, R.A.; Anderson, S.G.; Hartemann, F.V.; Houck, T.L.; /LLNL, Livermore

2012-09-07T23:59:59.000Z

497

Electronic properties of InP (001)/HfO{sub 2} (001) interface: Band offsets and oxygen dependence  

SciTech Connect (OSTI)

Using ab-initio methods, atomic structures and electronic properties of InP (001)/HfO{sub 2} (001) interface are studied within the framework of density functional theory. We examine the InP/HfO{sub 2} model interface electronic structures under varying oxidation conditions. The effects of indium and phosphorous concentrations on interfacial bonding, defect states, band offsets, and the thermodynamic stability at the interface are also investigated. The origin of interfacial gap states in InP (001)/HfO{sub 2} (001) interface are proposed, mainly from the P-rich oxides, which is validated by our experimental work. This highlights the importance of surface passivation prior to high-? deposition based on the in situ spectroscopic results of atomic layer deposition of HfO{sub 2} on InP.

KC, Santosh; Dong, Hong; Longo, Roberto C.; Xiong, Ka [Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080 (United States); Wang, Weichao [Department of Electronics and Microelectronics and Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, Nankai University, Tianjin 300071 (China); Wallace, Robert M.; Cho, Kyeongjae, E-mail: kjcho@utdallas.edu [Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080 (United States); Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080 (United States)

2014-01-14T23:59:59.000Z

498

Comparative cytotaxonomy in the tribe Bovini studied by banding techniques  

E-Print Network [OSTI]

Committee: Dr. James E. Womack Chromosomes of eight species of the tribe Bovini were studied by G ? banding, C ? banding and silver staining techniques. The results of this comparative cytogenetic study support the theory that Robertsonian fusion... in the tribe Bovini whose species appear to differ by a series of centromeric fusions. The phylogenetic tree derived from the cytogenetic data of this study is not consistent with morphological and behavioral trees previously described for the tribe Bovini...

Rich, Donna Carol

2012-06-07T23:59:59.000Z

499

Method of Controlling Corona Effects and Breakdown Voltage of Small Air Gaps Stressed by Impulse Voltages  

E-Print Network [OSTI]

This paper investigates the influence of a resistor on the dielectric behavior of an air gap. The resistor is connected in series with the air gap and the latter is stressed by impulse voltage. Air gap arrangements of different geometry with either the rod or the plate grounded are stressed with impulse voltages of both positive and negative polarity. The resistor is connected in series with the air gap in the return circuit connecting the gap with the impulse generator. The method followed involves the investigation of the graphs of the charging time concerning the air gaps capacitances, in connection to the value of the resistor, the geometry of the gap, the effect of grounding and the polarity effect. It is determined that the charging time of the air gap increases, as the value of the resistor increases. It is also determined that the peak voltage value of the fully charged air gap decreases as the value of the resistor increases. The results of the mathematical and simulation analysis are compared with the results of the oscillograms taken from experimental work. In addition and consequently to the above results it is concluded from the experimental work that the in series connection of the resistor in the circuit has significant influence on corona pulses (partial discharges) occurring in the gap and on the breakdown voltage of the gap. A new method of controlling the corona effects and consequently the breakdown voltage of small air gaps stressed by impulse voltage of short duration in connection to the ground effect and the polarity effect has arisen. Furthermore through mathematical analysis of the charging graphs obtained from simulation and experimental oscillograms there was a calculation of the values of the capacitance of the air gaps in relation to their geometry and the results were compared to the values calculated with mathematical analysis.

Athanasios Maglaras; Trifon Kousiouris; Frangiskos Topalis; Dimitrios Katsaros; Leandros A. Maglaras; Konstantina Giannakopoulou

2014-10-15T23:59:59.000Z

500

Shear band dynamics from a mesoscopic modeling of plasticity  

E-Print Network [OSTI]

The ubiquitous appearance of regions of localized deformation (shear bands) in different kinds of disordered materials under shear is studied in the context of a mesoscopic model of plasticity. The model may or may not include relaxational (aging) effects. In the absence of relaxational effects the model displays a monotonously increasing dependence of stress on strain-rate, and stationary shear bands do not occur. However, in start up experiments transient (although long lived) shear bands occur, that widen without bound in time. I investigate this transient effect in detail, reproducing and explaining a t^1/2 law for the thickness increase of the shear band that has been obtained in atomistic numerical simulations. Relaxation produces a negative sloped region in the stress vs. strain-rate curve that stabilizes the formation of shear bands of a well defined width, which is a function of strain-rate. Simulations at very low strain-rates reveal a non-trivial stick-slip dynamics of very thin shear bands that has relevance in the study of seismic phenomena. In addition, other non-stationary processes, such as stop-and-go, or strain-rate inversion situations display a phenomenology that matches very well the results of recent experimental studies.

E. A. Jagla

2010-06-07T23:59:59.000Z