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1

Electronic materials with a wide band gap: recent developments  

Science Journals Connector (OSTI)

Usually, semiconductors with a band gap Eg 3 eV or larger are called wide band gap materials. Their optical emission can span the whole of the visible spectrum, enabling the development of devices for solid-state lighting. In addition, a large Eg results in a high electrical breakthrough field, which is interesting for high-power electronics.

Klimm, D.

2014-08-29T23:59:59.000Z

2

InAlAs EPITAXIAL GROWTH FOR WIDE BAND GAP SOLAR CELLS Marina S. Leite  

E-Print Network [OSTI]

InAlAs EPITAXIAL GROWTH FOR WIDE BAND GAP SOLAR CELLS Marina S. Leite 1 , Robyn L. Woo 2 , William vapor phase epitaxy and wide band gap solar cell fabrication. X-ray diffraction and transmissionAlAs solar cells lattice-matched to InP were grown and electrically characterized under AM 1.5 global 1-sun

Atwater, Harry

3

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

4

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

5

Wide-band-gap solar cells with high stabilized performance. Annual subcontract report, July 15, 1994--July 14, 1995  

SciTech Connect (OSTI)

This report describes work performed by Pennsylvania State University in collaboration with the NREL Wide-Band-Gap Team. The goal of this team is to develop a single-junction, wide-gap solar cell with good stabilized parameters. The objectives of the subcontract are to (1) develop a cost-effective amorphous silicon PV technology to foster a viable amorphous silicon PV industry in the US, ensuring that this industry remains a world leader in the a-Si technology; (2) help the US a-Si PV industry achieve the US DOE PV Program FY 1995 milestone of 10% stable efficiency commercial thin-film modules; (3) help the US a-Si PV industry achieve 12% stable efficiency multi-junction a-Si:H modules for large-scale utility use by the year 2005. Issues covered in this report include (1) improved understanding of stability in materials and solar cells, (2) intrinsic materials optimization, (3) solar cells optimized for intrinsic layer performance, (4) p-type layer optimization, (5) top cell interfaces, and (6) solar cell grading.

Wronski, C.R.; Collins, R.W.; Fonash, S.J. [Pennsylvania State Univ., University Park, PA (United States)

1995-11-01T23:59:59.000Z

6

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

7

Wide band-gap, fairly conductive p-type hydrogenated amorphous silicon carbide films prepared by direct photolysis; solar cell application  

SciTech Connect (OSTI)

Wide optical band-gap (2.0--2.3 eV) undoped and boron-doped hydrogenated amorphous silicon carbide (a-SiC:H) films have been prepared by both direct photo and rf glow discharge (GD plasma) decomposition of pure methylsilanes or acetylene and disilane gas mixtures. The photochemically prepared p-type films showed higher dark conductivities and lower activation energies. For an optical band gap of 2.0 eV a high conductivity of 7.0 x 10/sup -5/ (S cm/sup -1/) and a low activation energy of 0.33 eV have been measured. The first trial of these wide band-gap, fairly conductive films as a window layer in a p-i-n solar cell showed the high conversion efficiency of 9.46% under AM1 insolation.

Yamada, A.; Kenne, J.; Konagai, M.; Takahashi, K.

1985-02-01T23:59:59.000Z

8

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

E-Print Network [OSTI]

PHYSICAL REVIEW B 85, 155101 (2012) Electronic properties of layered multicomponent wide 2012) The structural, electronic, and optical properties of 12 multicomponent oxides with layered self-consistent screened-exchange local density approximation calculations. Strikingly, despite

Medvedeva, Julia E.

9

Low band gap polymers Organic Photovoltaics  

E-Print Network [OSTI]

Low band gap polymers for Organic Photovoltaics Eva Bundgaard Ph.D. Dissertation Risø 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

10

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

11

Efficient Band Gap Prediction for Solids  

E-Print Network [OSTI]

An efficient method for the prediction of fundamental band gaps in solids using density functional theory (DFT) is proposed. Generalizing the Delta self-consistent-field (?SCF [delta SCF]) method to infinite solids, the ...

Chan, Maria K.

12

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

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

Band-Gap Engineering of Carbon Nanotubes with Grain Boundaries. Band-Gap Engineering of Carbon Nanotubes with Grain Boundaries. Abstract: Structure and electronic properties of...

13

Wide-gap a-Si:H fabricated by controlling voids  

SciTech Connect (OSTI)

High quality wide gap hydrogenated amorphous silicon has been prepared using the chemical annealing technique. It was possible to prepare materials with band gaps ranging 1.8 to 2.1 eV by varying the preparation parameters. Low defect densities less than (3--8) {times} 10{sup 15} cm{sup {minus}3} could be maintained over the entire band gap range. Improved stability for light soaking was also observed in the wide gap materials.

Yoshino, K.; Futako, W.; Wasai, Y.; Shimizu, I. [Tokyo Inst. of Tech., Yokohama (Japan). Graduate School

1996-12-31T23:59:59.000Z

14

Anomalous Doppler effects in phononic band gaps  

Science Journals Connector (OSTI)

Doppler effects in periodic acoustic media were studied theoretically and experimentally. Analytical formulas are derived using the Green’s function formalism. We found that a far field observer cannot hear the sound inside a band gap from a stationary source, but a moving source can be heard even if the frequency is inside the gap, and the Doppler shifts can be inverted or anomalously large.

Xinhua Hu; Zhihong Hang; Jensen Li; Jian Zi; C. T. Chan

2006-01-30T23:59:59.000Z

15

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

16

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...

17

Ideal Soliton Environment Using Parametric Band Gaps  

Science Journals Connector (OSTI)

Simultaneous solitary wave solutions for laser propagation in nonlinear parametric media with up to ( 3+1) dimensions are proved to exist. The combination of the large dispersion of a Bragg grating and the strong nonlinearity of ?(2) optical material results in stable behavior with short interaction distances and low power requirements. The solutions are obtained by using the effective mass approximation to reduce the coupled propagation equations to those describing a dispersive parametric nonlinear waveguide, and are verified by solving the complete set of coupled band-gap equations numerically.

H. He and P. D. Drummond

1997-06-09T23:59:59.000Z

18

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

19

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...

20

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...

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

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

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

A New Gap-Opening Mechanism in a A New Gap-Opening Mechanism in a Triple-Band Metal A New Gap-Opening Mechanism in a Triple-Band Metal Print Wednesday, 23 February 2005 00:00 A "wire" of indium only one or a few atoms wide grown on a silicon surface comprises an ideal test laboratory for studying one-dimensional (1D) metals. A new example comes from a collaboration between researchers from Yonsei University in Korea, the ALS, and the University of Oregon, who have discovered that the phase transition from metal to insulator that occurs at low temperature in indium wires on the silicon (111) surface involves not only the expected shift in the electronic structure (band-gap opening) but also a band restructuring that gives rise to an energy gap in a second band. Three's a Crowd

22

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 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 devices, have to overcome silicon's superb collection of materials properties as well as sophisticated fabrication technologies refined by six decades of effort by materials scientists and engineers. Graphene, one of the latest contenders, has a rather impressive list of features of its own but has lacked a key characteristic of all semiconductors, an energy gap (band gap) in its electronic band structure. A multi-institutional collaboration under the leadership of researchers with Berkeley Lab and the University of California, Berkeley, have now demonstrated that growing an epitaxial film of graphene on a silicon carbide substrate results in a significant band gap, 0.26 electron volts (eV), an important step toward making graphene useful as a semiconductor.

23

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 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 devices, have to overcome silicon's superb collection of materials properties as well as sophisticated fabrication technologies refined by six decades of effort by materials scientists and engineers. Graphene, one of the latest contenders, has a rather impressive list of features of its own but has lacked a key characteristic of all semiconductors, an energy gap (band gap) in its electronic band structure. A multi-institutional collaboration under the leadership of researchers with Berkeley Lab and the University of California, Berkeley, have now demonstrated that growing an epitaxial film of graphene on a silicon carbide substrate results in a significant band gap, 0.26 electron volts (eV), an important step toward making graphene useful as a semiconductor.

24

Synthesis of electromagnetic modes in photonic band gap fibers  

E-Print Network [OSTI]

In this paper, we report on the successful synthesis of three individual modes, HE11, TEo0, and TE02 for transmission in photonic band gap fibers at near infrared wavelengths. We measure the propagation losses of the HE11 ...

Hu, Qichao

2007-01-01T23:59:59.000Z

25

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

26

Entanglement Sudden Death in Band Gaps  

E-Print Network [OSTI]

Using the pseudomode method, we evaluate exactly time-dependent entanglement for two independent qubits, each coupled to a non-Markovian structured environment. Our results suggest a possible way to control entanglement sudden death by modifying the qubit-pseudomode detuning and the spectrum of the reservoirs. Particularly, in environments structured by a model of a density-of-states gap which has two poles, entanglement trapping and prevention of entanglement sudden death occur in the weak-coupling regime.

Ying-Jie Zhang

2009-11-10T23:59:59.000Z

27

Systematic Study of Electronic Phases, Band Gaps and Band Overlaps of Bismuth Antimony Nanowires  

E-Print Network [OSTI]

We have developed an iterative one dimensional model to study the narrow band-gap and the associated non-parabolic dispersion relations for bismuth antimony nanowires. An analytical approximation has also been developed. Based on the general model, we have developed, we have calculated and analyzed the electronic phase diagrams and the band-gap/band-overlap map for bismuth antimony nanowires, as a function of stoichiometry, growth orientation, and wire width.

Shuang Tang; Mildred Dresselhaus

2013-12-03T23:59:59.000Z

28

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

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

A New Gap-Opening Mechanism in a Triple-Band Metal Print A New Gap-Opening Mechanism in a Triple-Band Metal Print A "wire" of indium only one or a few atoms wide grown on a silicon surface comprises an ideal test laboratory for studying one-dimensional (1D) metals. A new example comes from a collaboration between researchers from Yonsei University in Korea, the ALS, and the University of Oregon, who have discovered that the phase transition from metal to insulator that occurs at low temperature in indium wires on the silicon (111) surface involves not only the expected shift in the electronic structure (band-gap opening) but also a band restructuring that gives rise to an energy gap in a second band. Three's a Crowd For the condensed-matter physicist, the words "electronic structure" are what it's all about. Short-hand for a description of the way electrons behave in solids, liquids, molecules, and even atoms, electronic structure underlies almost all of the everyday properties of matter from structural strength to electrical conductivity. For example, metals conduct electricity because some of their electrons have access to a continuous band of energies, whereas a break or gap in the band turns the metal into an insulator.

29

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

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

A New Gap-Opening Mechanism in a Triple-Band Metal Print A New Gap-Opening Mechanism in a Triple-Band Metal Print A "wire" of indium only one or a few atoms wide grown on a silicon surface comprises an ideal test laboratory for studying one-dimensional (1D) metals. A new example comes from a collaboration between researchers from Yonsei University in Korea, the ALS, and the University of Oregon, who have discovered that the phase transition from metal to insulator that occurs at low temperature in indium wires on the silicon (111) surface involves not only the expected shift in the electronic structure (band-gap opening) but also a band restructuring that gives rise to an energy gap in a second band. Three's a Crowd For the condensed-matter physicist, the words "electronic structure" are what it's all about. Short-hand for a description of the way electrons behave in solids, liquids, molecules, and even atoms, electronic structure underlies almost all of the everyday properties of matter from structural strength to electrical conductivity. For example, metals conduct electricity because some of their electrons have access to a continuous band of energies, whereas a break or gap in the band turns the metal into an insulator.

30

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

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

A New Gap-Opening Mechanism in a Triple-Band Metal Print A New Gap-Opening Mechanism in a Triple-Band Metal Print A "wire" of indium only one or a few atoms wide grown on a silicon surface comprises an ideal test laboratory for studying one-dimensional (1D) metals. A new example comes from a collaboration between researchers from Yonsei University in Korea, the ALS, and the University of Oregon, who have discovered that the phase transition from metal to insulator that occurs at low temperature in indium wires on the silicon (111) surface involves not only the expected shift in the electronic structure (band-gap opening) but also a band restructuring that gives rise to an energy gap in a second band. Three's a Crowd For the condensed-matter physicist, the words "electronic structure" are what it's all about. Short-hand for a description of the way electrons behave in solids, liquids, molecules, and even atoms, electronic structure underlies almost all of the everyday properties of matter from structural strength to electrical conductivity. For example, metals conduct electricity because some of their electrons have access to a continuous band of energies, whereas a break or gap in the band turns the metal into an insulator.

31

A V-BAND MMIC OSCILLATOR ARRAY USING WIDE BAND MICROSTRIP PATCH ANTENNA  

E-Print Network [OSTI]

A V-BAND MMIC OSCILLATOR ARRAY USING WIDE BAND MICROSTRIP PATCH ANTENNA HONG-TUEK KIM, WOOYEOL CHOI in a push-pull mode was implemented using two 2-port patch antennas. When measured in a closed over]. In this paper, to improve this problem, we develop a modified wide band microstrip patch antenna and use

Kwon, Youngwoo

32

Lattice Boltzmann model for photonic band gap materials  

Science Journals Connector (OSTI)

An efficient technique for computing photonic band structure and defect modes is proposed based on the lattice Boltzmann model. Physically, it is a scheme based on the kinetics of the virtual microscopic process, rather than a solution of the macroscopic Maxwell equations. The method has significant advantages of being naturally suited for massively parallel machine, as well as speed and convenience, providing another methodology for photonic band gap materials and, also, for general electromagnetic scattering problems in open region when incorporated with the perfectly matched layer technique.

Zhifang Lin; Haiping Fang; Jianjun Xu; Jian Zi; Xiangdong Zhang

2003-02-07T23:59:59.000Z

33

Band-Gap Engineering of Carbon Nanotubes with Grain Boundaries  

SciTech Connect (OSTI)

Structure and electronic properties of carbon nanotubes (CNTs) with grain boundaries (GBs) are investigated using density-functional calculations, where the GBs parallel and perpendicular to the tube axis are considered. Simulation results show that the GBs have a great effect on the electronic properties of the CNTs. For the GBs along the tube axis, the CNTs are narrow or zero band gap (<0.16 eV) materials, independent of the misorientation angle and diameter. For the GBs perpendicular to the tube axis, localized electronic states appear within the GBs regions, leading to a larger band gap of up to 0.6 eV. It is convenient to transport and localize the electrons and holes by engineering the GBs. These findings are of great significance for developing carbon-based nanomaterials and electronic devices.

Wang, Zhiguo; Zhou, Yungang; Zhang, Yanwen; Gao, Fei

2012-01-26T23:59:59.000Z

34

Band-Gap Engineering of Carbon Nanotubes with Grain Boundaries  

SciTech Connect (OSTI)

Structure and electronic properties of carbon nanotubes (CNTs) with grain boundaries (GBs) are investigated using density-functional calculations, where the GBs parallel and perpendicular to the tube axis are considered. Simulation results show that the GBs have a great effect on the electronic properties of the CNTs. For the GBs along the tube axis, the CNTs are narrow or zero band gap (<0.16 eV) materials, independent of the misoritentaion angle and diameter. For the GBs perpendicular to the tube axis, localized electronic states appear within the GBs regions, leading to a larger band gap of up to 0.6 eV. It is convenient to transport and localize the electrons and holes by engineering the GBs. These findings are of great significance for developing carbon-based nanomaterials and electronic devices.

Wang, Zhiguo [Department of Applied Physics, University of Electronic Science and Technology of China; Zhou, Yungang [Department of Applied Physics, University of Electronic Science and Technology of China; Zhang, Yanwen [ORNL; Gao, Fei [ORNL

2011-01-01T23:59:59.000Z

35

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...

36

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

37

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

38

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

39

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

40

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

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

Ternary silicon germanium nitrides: A class of tunable band gap materials  

Science Journals Connector (OSTI)

Ternary silicon germanium nitrides with compositions of both Si1?xGexN and (Si1?xGex)3N4 are predicted to have a band gap that decreases as the germanium:silicon ratio increases. The band gap is indirect for the silicon-rich compounds but becomes direct as the germanium content increases, due to greater mixing of s and p states in the conduction band. This effect of band gap tunability has recently been reported for (Si1?xGex)3N4 in the spinel structure [Boyko et al., Phys. Rev. B 81, 155207 (2010)]. Our results suggest that this is a more general effect and that ternary group-14 nitrides should form a class of semiconducting materials for which the band gap can be tuned by controlling the composition.

Judy N. Hart; Neil L. Allan; Frederik Claeyssens

2011-12-27T23:59:59.000Z

42

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 Å, 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 Educação, Ciência e Tecnologia do Ceará, 60040-531 Fortaleza-CE (Brazil)] [Instituto de Educação, Ciência 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

43

Wide-band neutrino beams at 1000 GeV  

SciTech Connect (OSTI)

In a previous publication, S. Mori discussed various broad-band neutrino and antineutrino beams using 1000 GeV protons on target. A new beam (SST) has been designed which provides the same neutrino flux as the quadrupole triplet (QT) while suppressing the wrong sign flux by a factor of 18. It also provides more than twice as much high energy antineutrino flux than the sign-selected bare target (SSBT) and in addition, has better neutrino suppression. While it is possible to increase the flux obtained from the single horn system over that previously described, the conclusion which states any horn focussing system seems to be of marginal use for Tevatron neutrino physics, is unchanged. Neutrino and antineutrino event rates and wrong sign backgrounds were computed using NUADA for a 100 metric ton detector of radius 1.5 meters. Due to radiation considerations and the existing transformer location, the horn beam is placed in its usual position inside the Target Tube. All other beams are placed in Fronthall. Thus, for the wide-band Fronthall trains a decay distance of 520 meters is used, versus 400 meters for the horn train. (WHK)

Malensek, A.; Stutte, L.

1983-04-11T23:59:59.000Z

44

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

45

Analytical descriptions of the band structure of direct-band-gap zinc-blende-structure semiconductors in the k?p Kane model  

Science Journals Connector (OSTI)

In the framework of the well-known k?p Kane band theory, accurate analytical approximations of conduction- and valence-band dispersion of direct-band-gap zinc-blende-structure semiconductors are derived when the spin-orbit-splitting energy does not exceed the band-gap energy. These approximations include the interactions with the remote bands. The expressions of the eigenfunctions are also obtained. The present analysis elucidates and unifies previous analytical band descriptions.

H.-J. Drouhin and J. Peretti

1991-10-15T23:59:59.000Z

46

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

47

Triple photonic band-gap structure dynamically induced in the presence of spontaneously generated coherence  

SciTech Connect (OSTI)

We study a cold atomic sample coherently driven into the five-level triple-{Lambda} configuration for attaining a dynamically controlled triple photonic band-gap structure. Our numerical calculations show that three photonic band gaps with homogeneous reflectivities up to 92% can be induced on demand around the probe resonance by a standing-wave driving field in the presence of spontaneously generated coherence. All these photonic band gaps are severely malformed with probe reflectivities declining rapidly to very low values when spontaneously generated coherence is gradually weakened. The triple photonic band-gap structure can also be attained in a five-level chain-{Lambda} system of cold atoms in the absence of spontaneously generated coherence, which however requires two additional traveling-wave fields to couple relevant levels.

Gao Jinwei; Bao Qianqian; Wan Rengang; Cui Cuili; Wu Jinhui [College of Physics, Jilin University, Changchun 130012 (China)

2011-05-15T23:59:59.000Z

48

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

E-Print Network [OSTI]

Jul 10, 2009 ... the dielectric material and the wave vector. .... which SDP can be well applied, thanks to its efficiency and robustness of handling this type of ...... Band diagrams plotted in the figures below show the eigenvalues moving along ...

2009-07-10T23:59:59.000Z

49

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

50

Measurements of CsI band-gap closure to 93 GPa  

Science Journals Connector (OSTI)

Infrared-absorption measurements to a peak pressure of 93 GPa document the pressure-induced closure of the band gap of CsI to about 4450 cm-1 (0.55 eV). In accord with previous spectroscopic measurements to 60 GPa, our data show that the band gap of CsI decreases continuously with pressure, and metallization (complete closure of the gap) is expected to occur above 100 GPa. A recent claim that CsI becomes metallic at 65±5 GPa is therefore spurious.

Quentin Williams and Raymond Jeanloz

1986-01-13T23:59:59.000Z

51

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; Råsander, 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

52

Strain-induced band-gap engineering of graphene monoxide and its effect on graphene  

Science Journals Connector (OSTI)

Using first-principles calculations we demonstrate the feasibility of band-gap engineering in two-dimensional crystalline graphene monoxide (GMO), a recently reported graphene-based material with a 1:1 carbon/oxygen ratio. The band gap of GMO, which can be switched between direct and indirect, is tunable over a large range (0–1.35 eV) for accessible strains. Electron and hole transport occurs predominantly along the zigzag and armchair directions (armchair for both) when GMO is a direct- (indirect-) gap semiconductor. A band gap of ?0.5 eV is also induced in graphene at the K? points for GMO/graphene hybrid systems.

H. H. Pu; S. H. Rhim; C. J. Hirschmugl; M. Gajdardziska-Josifovska; M. Weinert; J. H. Chen

2013-02-13T23:59:59.000Z

53

Band gaps in InN/GaN superlattices: Nonpolar and polar growth directions  

SciTech Connect (OSTI)

The electronic structures of nonpolar short-period InN/GaN superlattices (SLs) grown in the wurtzite a- and m-directions have been calculated and compared to previous calculations for polar superlattices (grown in the c-direction). The variation of the band gaps with the composition (m, n) of the mInN/nGaN unit cells of the superlattices was examined. The band structures were obtained by self-consistent calculations based on the local density approximation to the density functional theory using the Linear-Muffin-Tin-Orbital method with a semi-empirical correction for the band gaps. The calculated band gaps and their pressure coefficients for nonpolar superlattices are similar to those calculated for bulk InGaN alloys with an equivalent In/Ga concentration ratio. This is very different from what has been found in polar superlattices where the band gaps are much smaller and vanish when the number m of InN layers in the unit cell exceeds three. A strong internal electric field is responsible for this behavior of polar structures. Experimental photoluminescence data for polar SLs agree very well with gaps calculated for the nonpolar structures. It is suggested that this is caused by screening of the electric field in the polar structures by carriers originating from unintentional defects.

Gorczyca, I., E-mail: iza@unipress.waw.pl; Skrobas, K.; Suski, T. [Institute of High Pressure Physics, UNIPRESS, 01-142 Warsaw (Poland); Christensen, N. E.; Svane, A. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

2013-12-14T23:59:59.000Z

54

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

55

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

56

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

57

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

58

Forward Raman compression via photonic band gap in metals or warm dense matter  

SciTech Connect (OSTI)

The group velocity of a light pulse in photonic band gap material could considerably deviate from the speed of light in vacuum. A forward stoke and a pump pulse of different speeds would enable the Raman compression in metals or the warm dense matter. A small window of the parameter regime, where the compression is feasible via the forward Raman scattering, is identified.

Son, S. [18 Caleb Lane, Princeton, New Jersey 08540 (United States); Moon, Sung Joon [Program in Applied and Computational Mathematics, Princeton University, Princeton, New Jersey 08544 (United States)

2011-08-15T23:59:59.000Z

59

Composition and temperature-induced effects on the phonon spectra of narrow-band-gap Hg1-xCdxTe  

Science Journals Connector (OSTI)

Compositional and temperature-dependent Raman and infrared spectroscopies on the narrow-band-gap II-VI alloy, Hg1-xCdxTe (0?x?0.29), are reported in this paper. Raman measurements over this composition range confirm the two-mode behavior of the optical phonons in the alloy, with the frequency positions exhibiting a monotonic change with the alloy composition x. A resonant enhancement of the HgTe-like forbidden longitudinal-optic mode is observed near the E1 band gap of the alloy. Alloy induced perturbations on the electronic states lead to a smearing and a weakening of the resonance with increasing alloy composition. The optical phonons in this small band-gap alloy exhibit anomalous frequency shifts as a function of temperature vis-à-vis normal wide-band-gap semiconductors. This anomaly is attributed to the strong electron-phonon interaction in narrow-band-gap systems, which overshadows the dominant anharmonic (phonon-phonon) interaction in usual semiconductors. A detailed compositional dependent second-order Raman spectra is also reported.

Shyama Rath, K. P. Jain, S. C. Abbi, C. Julien, and M. Balkanski

1995-12-15T23:59:59.000Z

60

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

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

Inorganic Graphenylene: A Porous Two-Dimensional Material With Tunable Band Gap  

E-Print Network [OSTI]

By means of ab initio calculations we investigate the possibility of existence of a boron nitride (BN) porous two-dimensional nanosheet which is geometrically similar to the carbon allotrope known as biphenylene carbon. The proposed structure, which we called Inorganic Graphenylene (IGP), is formed spontaneously after selective dehydrogenation of the porous Boron Nitride (BN) structure proposed by Ding et al. We study the structural and electronic properties of both porous BN and IGP and it is shown that, by selective substitution of B and N atoms with carbon atoms in these structures, the band gap can be significantly reduced, changing their behavior from insulators to semiconductors, thus opening the possibility of band gap engineering for this class of two-dimensional materials.

Perim, Eric; Atreto, Pedro Alves da Silva; Galvão, Douglas

2014-01-01T23:59:59.000Z

62

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

63

Electron Beam Source Molecular Beam Epitaxy of AlxGal?xAs Graded Band Gap Device Structures  

Science Journals Connector (OSTI)

A new method has been developed for the growth of graded band-gap AlxGal?xAs alloys by molecular beam epitaxy which is based upon electron. beam evaporation of the Group III elements ... . The large dynamic respo...

R. J. Malik; A. F. J. Levi; B. F. Levine…

1989-01-01T23:59:59.000Z

64

Multi junction solar cells using band-gap induced cascaded light absorption  

Science Journals Connector (OSTI)

We propose multi junction solar cells using an optical reflection system formed by arranging plural solar cells in decreasing order of their band gaps for achieving cascaded light absorption by their own band gaps: the first solar cell absorbs some light with a photon energy higher than the highest band gap and reflects the residual light with a lower photon energy to the second solar cell. We further propose to use plural batteries for charging electrical power generated by the individual solar cells to overcome the current matching problem in the multi-junction solar cells. We experimentally demonstrated reflection-type multi junction solar cells using commercially available hydrogenated amorphous silicon (a-Si:H) and crystalline silicon (c-Si) solar cells using air mass 1.5 light illumination. A high open circuit voltage of 24.3 V was achieved, which was a sum of 19.3 and 5.0 V for the individual a-Si:H and c-Si solar cells. However, since there was no current matching between the a-Si:H and c-Si solar cells, the a-Si:H?c-Si serially connected solar cell gave a maximum power of 0.057 W, which was lower than 0.063 W, the sum of those for the individual a-Si:H and c-Si solar cells. The method of charging electrical power from individual solar cells is useful to efficiently achieve electrical power from individual a-Si:H and c-Si solar cells in the absence of current matching in multi junction solar cells.

Toshiyuki Sameshima; Hitomi Nomura; Shinya Yoshidomi; Masahiko Hasumi

2014-01-01T23:59:59.000Z

65

Photonic band gaps in three-dimensional network structures with short-range order  

SciTech Connect (OSTI)

We present a systematic study of photonic band gaps (PBGs) in three-dimensional (3D) photonic amorphous structures (PASs) with short-range order. From calculations of the density of optical states (DOS) for PASs with different topologies, we find that tetrahedrally connected dielectric networks produce the largest isotropic PBGs. Local uniformity and tetrahedral order are essential to the formation of PBGs in PASs, in addition to short-range geometric order. This work demonstrates that it is possible to create broad, isotropic PBGs for vector light fields in 3D PASs without long-range order.

Liew, Seng Fatt; Noh, Heeso [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States); Yang, Jin-Kyu [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States); Department of Optical Engineering, Kongju National University, Kongju 314-701 (Korea, Republic of); Schreck, Carl F. [Department of Physics, Yale University, New Haven, Connecticut 06511 (United States); Dufresne, Eric R. [Department of Physics, Yale University, New Haven, Connecticut 06511 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06511 (United States); Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511 (United States); Department of Cell Biology, Yale University, New Haven, Connecticut 06511 (United States); O'Hern, Corey S. [Department of Physics, Yale University, New Haven, Connecticut 06511 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06511 (United States); Cao, Hui [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States); Department of Physics, Yale University, New Haven, Connecticut 06511 (United States)

2011-12-15T23:59:59.000Z

66

Photovoltages Larger than the Band Gap in Thin Films of Germanium  

Science Journals Connector (OSTI)

Photovoltages much larger than the band gap were investigated in thin films of germanium deposited obliquely onto Pyrex substrates. The voltages were studied as functions of angle of deposit film thickness intensity of illumination temperature and ambient atmosphere. A model is presented which explains the following observations. Positive and negative photovoltages exist simultaneously in a single sample; which of these predominates changes with time. Dark resistance and photovoltage exhibit the same temperature dependence with identical activation energies indicating that both dark resistance and photovoltage arise from the same elementary processes.

H. Kallmann; G. Marmor Spruch; S. Trester

1972-01-01T23:59:59.000Z

67

Is it effective to harvest visible light by decreasing the band gap of photocatalytic materials?  

SciTech Connect (OSTI)

In situ variations in the electron work function and photo-current of TiO{sub 2} nanotubes demonstrate that long-wavelength illumination only has a minor effect on the excitation of electrons in the nanotubes after being exposed to short-wavelength light or when the short-wavelength light coexisted, indicating that the solar spectrum may not be utilized as efficiently as expected by extending the absorption spectrum of the photocatalytic material to visible light range with decreased band gaps.

Fu Ning; Tang Xinhu; Li Dongyang [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2G6 (Canada)

2012-02-27T23:59:59.000Z

68

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

69

Pseudomorphic GeSn/Ge(001) quantum wells: Examining indirect band gap bowing  

SciTech Connect (OSTI)

A study of the bandgap character of compressively strained GeSn{sub 0.060-0.091}/Ge(001) quantum wells grown by molecular beam epitaxy is reported. The built-in strain in GeSn wells leads to an increased separation between L and {Gamma} conduction band minima. The prevalent indirect interband transitions in GeSn were probed by photoluminescence spectroscopy. As a result we could simulate the L-valley bowing parameter in GeSn alloys, b{sub L} = 0.80 {+-} 0.06 eV at 10 K. From this we conclude that even compressively strained GeSn/Ge(001) alloys could become direct band gap semiconductors at the Sn-fraction higher than 17.0 at. %.

Tonkikh, Alexander A. [Max Planck Institute of Microstructure Physics, Weinberg 2 D-06120, Halle (Saale) (Germany); Institute for Physics of Microstructures RAS, GSP-105, Nizhniy Novgorod (Russian Federation); Eisenschmidt, Christian; Schmidt, Georg [Institute of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 3 D-01620, Halle (Saale) (Germany); Talalaev, Vadim G. [Max Planck Institute of Microstructure Physics, Weinberg 2 D-06120, Halle (Saale) (Germany); ZIK SiLi-Nano, Martin Luther University Halle-Wittenberg, Karl-Freiherr-von-Fritsch-Str. 3 D-06120, Halle (Saale) (Germany); Zakharov, Nikolay D.; Werner, Peter [Max Planck Institute of Microstructure Physics, Weinberg 2 D-06120, Halle (Saale) (Germany); Schilling, Joerg [ZIK SiLi-Nano, Martin Luther University Halle-Wittenberg, Karl-Freiherr-von-Fritsch-Str. 3 D-06120, Halle (Saale) (Germany)

2013-07-15T23:59:59.000Z

70

Stabilization of temperature dependence of band Gap by introducing nitrogen ion into GaInNP alloy  

SciTech Connect (OSTI)

The photoluminescence (PL) spectra of GaInNP are observed to survey the origin of the unique behavior of the band gap caused by incorporating nitrogen ions. The temperature dependence of the PL peak position is carefully analyzed. It is found that the reduction of the temperature alteration owing to the nitrogen incorporation arises from the hybridization between the nitrogen local 3s and 3p orbitals and the conduction band. In the GaInNP and host GaInP with the indium content around 50%, which has a direct band gap slightly lower than an X-valley, the band gap shrinkage with temperature is mediated by an LA phonon at X point.

Emura, Shuichi; Nonoguchi, Shogo; Kim, Kang Min [The Institute of Scientific and Industrial Research, Osaka Univ., Mihogaoka 8-1, Ibaraki, Osaka 567-0047 (Japan)

2013-12-04T23:59:59.000Z

71

Fano-Hopfield model and photonic band gaps for an arbitrary atomic lattice  

SciTech Connect (OSTI)

We study the light dispersion relation in a periodic ensemble of atoms at fixed positions in the Fano-Hopfield model (the atomic dipole being modeled with harmonic oscillators). Compared to earlier works, we do not restrict to cubic lattices, and we do not regularize the theory by hand but we renormalize it in a systematic way using a Gaussian cutoff in momentum space. Whereas no omnidirectional spectral gap is known for light in a Bravais atomic lattice, we find that, for a wide range of parameters, an omnidirectional gap occurs in a diamond atomic lattice, which may be realized in an experiment with ultracold atoms. The long-wavelength limit of the theory also provides a Lorentz-Lorenz (or Clausius-Mossotti) relation for an arbitrary lattice.

Antezza, Mauro; Castin, Yvan [Laboratoire Kastler Brossel, Ecole Normale Superieure, CNRS and UPMC, 24 rue Lhomond, 75231 Paris (France)

2009-07-15T23:59:59.000Z

72

Fano-Hopfield model and photonic band gaps for an arbitrary atomic lattice  

Science Journals Connector (OSTI)

We study the light dispersion relation in a periodic ensemble of atoms at fixed positions in the Fano-Hopfield model (the atomic dipole being modeled with harmonic oscillators). Compared to earlier works, we do not restrict to cubic lattices, and we do not regularize the theory by hand but we renormalize it in a systematic way using a Gaussian cutoff in momentum space. Whereas no omnidirectional spectral gap is known for light in a Bravais atomic lattice, we find that, for a wide range of parameters, an omnidirectional gap occurs in a diamond atomic lattice, which may be realized in an experiment with ultracold atoms. The long-wavelength limit of the theory also provides a Lorentz-Lorenz (or Clausius-Mossotti) relation for an arbitrary lattice.

Mauro Antezza and Yvan Castin

2009-07-21T23:59:59.000Z

73

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

74

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 ÷ 2000 nodes, MAC and network layer to develop wireless sensors networks tailored for oil (and gas) exploration

Savazzi, Stefano

75

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

SciTech Connect (OSTI)

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

Yang, Jin-Kyu; Noh, Heeso; Liew, Seng-Fatt [Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8482 (United States); Schreck, Carl [Department of Physics, Yale University, New Haven, Connecticut 06520-8120 (United States); Guy, Mikhael I. [Science and Research Software Core, Yale University, New Haven, Connecticut 06520-8286 (United States); O'Hern, Corey S. [Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520-8286 (United States); Department of Physics, Yale University, New Haven, Connecticut 06520-8120 (United States); Cao, Hui [Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8482 (United States); Department of Physics, Yale University, New Haven, Connecticut 06520-8120 (United States)

2010-11-15T23:59:59.000Z

76

More insights into band gap graded a-SiGe:H solar cells by experimental and simulated data  

SciTech Connect (OSTI)

An experimental and numerical study of a-SiGe:H based solar cells with band gap graded i-layer in the shape of a V is presented. The variation of the location of the band gap minimum has strong influence on the solar cell performance. Comparisons of experimental and simulated data of the dark IV-behavior, IV-curves under illumination and the quantum efficiency allow insights into the transport and recombination behavior within the solar cell. The simulations reveal that the position as well as the charge state of the defects determine the device characteristics.

Zimmer, J.; Stiebig, H.; Foelsch, J.; Finger, F.; Eickhoff, T.; Wagner, H.

1997-07-01T23:59:59.000Z

77

Plasma deposition of wide gap, highly photoconductive a-Si:H thin films from disilane-helium mixtures  

SciTech Connect (OSTI)

Wide gap (>1.9 eV), photoconductive, intrinsic amorphous silicon films were made in a uhv system from Si/sub 2/H/sub 6/-He mixtures. The hydrogen concentrations, optical gaps and photoconductivities were measured. Unlike films made from SiH/sub 4/, Si/sub 2/H/sub 6/-produced films exhibit excellent electronic properties even at low deposition temperatures. The ratio of AM1 photoconductivity to dark conductivity was as high as 10/sup 7/.

Rajeswaran, G.; Vanier, P.E.; Corderman, R.R.; Kampas, F.J.

1984-01-01T23:59:59.000Z

78

Topology and Design of Wide-Band 3D Metamaterials made of Periodically Loaded Transmission Line Arrays  

E-Print Network [OSTI]

Topology and Design of Wide-Band 3D Metamaterials made of Periodically Loaded Transmission Line index over a wide frequency band. These metamaterials consist of a three- dimensional transmission line and permeability. The cubic-cell transmission line host network is a physical realization of the 3D distributed

Tentzeris, Manos

79

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

80

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.

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

Anomalous temperature-dependent band gaps in CuInS2 studied by surface-barrier electroreflectance  

Science Journals Connector (OSTI)

The lowest-energy gaps of CuInS2 have been studied by low-field surface-barrier electroreflectance in the temperature range from 10 to 300 K. Anomalous temperature dependence of E0 and E0+?0 have been found. Below 120 K the temperature coefficient of the band gap is 4.3×10-5 eV/K for E0 and 5.8×10-5 eV/K for E0+?0. Above 120 K the coefficients become -8.7×10-5 eV/K and -4.4×10-5 eV/K for E0 and E0+?0. These temperature-dependent energy gaps are explained by the reduction of d levels in the upper valence band due to thermal expansion and the competition with the electron-phonon interaction. The temperature dependence of spin-orbit splitting in our experiment confirms this explanation.

T. M. Hsu and J. H. Lin

1988-03-15T23:59:59.000Z

82

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

83

Defects in wide band gap semiconductors: magneto-optical double resonance studies  

Science Journals Connector (OSTI)

Recent results obtained in the investigation of shallow donors in GaN with optical detection of electron paramagnetic resonance via the so-called yellow luminescence are reviewed as well as recent results on the silicon vacancy in SiC using optical detection of electron paramagnetic resonance via the magnetic circular dichroism of the absorption. The power of these double resonance methods is illustrated. The possibility of electrical detection of electron paramagnetic resonance in the electrical conductivity is also briefly discussed as future development.

Johann-Martin Spaeth

2004-01-01T23:59:59.000Z

84

Band gap tuning and optical absorption in type-II InAs/GaSb mid infrared short period superlattices: 14 bands K Dot-Operator p study  

SciTech Connect (OSTI)

The MBE growth of short-period InAs/GaSb type-II superlattice structures, varied around 20.5 A InAs/24 A GaSb were [J. Applied physics, 96, 2580 (2004)] carried out by Haugan et al. These SLs were designed to produce devices with an optimum mid-infrared photoresponse and a sharpest photoresponse cutoff. We have used a realistic and reliable 14-band k.p formalism description of the superlattice electronic band structure to calculate the absorption coefficient in such short-period InAs/GaSb type-II superlattices. The parameters for this formalism are known from fitting to independent experiments for the bulk materials. The band-gap energies are obtained without any fitting parameters, and are in good agreement with experimental data.

AbuEl-Rub, Khaled M. [Department of Applied Physical Sciences, Jordan University of Science and Technology Irbid, 21141 (Jordan)

2012-09-06T23:59:59.000Z

85

Plasma deposition of wide gap, highly photoconductive a-Si:H thin films from disilane-helium mixtures  

SciTech Connect (OSTI)

Wide gap (> 1.9 eV), photoconductive, intrinsic amorphous silicon films were made in a UHV system from Si/sub 2/H/sub 6/-He mixtures. The hydrogen concentrations, optical gaps and photoconductivities were measured. Unlike films made from SiH/sub 4/, Si/sub 2/H/sub 6/-produced films exhibit excellent electronic properties even at low deposition temperatures. The ratio of AM1 photoconductivity to dark conductivity was as high as 10/sup 7/. 17 references, 5 figures, 1 table.

Rajeswaran, G.; Vanier, P.E.; Corderman, R.R.; Kampas, F.J.

1985-01-01T23:59:59.000Z

86

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.

87

Photonic band gap in an imperfect atomic diamond lattice: Penetration depth and effects of finite size and vacancies  

Science Journals Connector (OSTI)

We study the effects of finite size and of vacancies on the photonic band gap recently predicted for an atomic diamond lattice. Close to a Jg=0?Je=1 atomic transition, and for atomic lattices containing up to N?3×104 atoms, we show how the density of states can be affected by both the shape of the system and the possible presence of a fraction of unoccupied lattice sites. We numerically predict and theoretically explain the presence of shape-induced border states and of vacancy-induced localized states appearing in the gap. We also investigate the penetration depth of the electromagnetic field which we compare to the case of an infinite system.

Mauro Antezza and Yvan Castin

2013-09-25T23:59:59.000Z

88

Emission of Band-Gap-Energy Positrons from Surfaces of LiF, NaF, and Other Ionic Crystals  

Science Journals Connector (OSTI)

Energetic positrons implanted into various ionic crystal surfaces are reemitted with a maximum kinetic energy (14.7 ± 0.7 eV for LiF) near the band-gap energy. The evidence suggests that, at least for LiF and NaF, the emission originates from bulk-formed positronium (Ps) breaking up after diffusing to the surface. In our model, the positrons are Auger emitted when the Ps electrons recombine with holes at the surface, and the spectrum of positron energies thus reflects the density of empty surface states.

A. P. Mills; Jr. and William S. Crane

1984-11-26T23:59:59.000Z

89

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

90

The properties of photonic band gaps for three-dimensional plasma photonic crystals in a diamond structure  

SciTech Connect (OSTI)

In this paper, the properties of photonic band gaps (PBGs) for two types of three-dimensional plasma photonic crystals (PPCs) composed of isotropic dielectric and unmagnetized plasma with diamond lattices are theoretically investigated for electromagnetic waves based on a modified plane wave expansion method. The equations for type-1 structure are theoretically deduced, which depend on the diamond lattices realization (dielectric spheres immersed in plasma background). The influences of dielectric constant of dielectric, plasma collision frequency, filling factor, and plasma frequency on PBGs are investigated, respectively, and some corresponding physical explanations and the possible methods to realize the three-dimensional PPCs in experiments are also given. From the numerical results, it has been shown that not only the locations but also the gap/midgap ratios of the PBGs for two types of PPCs can be tuned by plasma frequency, filling factor, and the relative dielectric constant, respectively. However, the plasma collision frequency has no effect on the frequency ranges and gap/midgap ratios of the PBGs for two types of PPCs.

Zhang Haifeng [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Nanjing Artillery Academy, Nanjing 211132 (China); Liu Shaobin [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); State Key Laboratory of Millimeter Waves of Southeast University, Nanjing Jiangsu 210096 (China); Kong Xiangkun, Chenchen; Bian Borui [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

2013-04-15T23:59:59.000Z

91

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

92

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

93

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

E-Print Network [OSTI]

-band spectrum sensing, Cognitive radio, Spectrum estimation. I. INTRODUCTION Efficient utilization of radio and services and the dearth of available spectrum for licensed allocation [13]. Recent spectrum measurements have shown that large portions of licensed spectrum, notably in the VHF-UHF bands licensed

Leus, Geert

94

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

95

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

SciTech Connect (OSTI)

Co3O4 exhibits intriguing physical, chemical and catalytic properties and has demonstrated great potential for next-generation renewable energy applications. These interesting properties and promising applications are underpinned by its electronic structure and optical properties, which are unfortunately poorly understood and the subject of considerable debate over many years. Here, we unveil a consistent electronic structural description of Co3O4 by synergetic infrared optical and in situ photoemission spectroscopy as well as standard density functional theory calculations. In contrast to previous assumptions, we demonstrate a much smaller fundamental band gap, which is directly related to its efficient electro-/photoactivity. The present results may help to advance the fundamental understanding and provide guidance for the use of oxidematerials in photocatalysis and solar applications.

Qiao, L.; Xiao, Haiyan Y.; Meyer, H. M.; Sun, J. N.; Rouleau, C. M.; Puretzky, A. A.; Geohegan, D. B.; Ivanov, Ilia N.; Yoon, M.; Weber, William J.; Biegalski, Michael D.

2013-08-21T23:59:59.000Z

96

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

97

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

98

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

99

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

100

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.

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

Analysis of photonic band gap in dispersive properties of tunable three-dimensional photonic crystals doped by magnetized plasma  

SciTech Connect (OSTI)

In this paper, the magnetooptical effects in dispersive properties for two types of three-dimensional magnetized plasma photonic crystals (MPPCs) containing homogeneous dielectric and magnetized plasma with diamond lattices are theoretically investigated for electromagnetic (EM) wave based on plane wave expansion (PWE) method, as incidence EM wave vector is parallel to the external magnetic field. The equations for two types of MPPCs with diamond lattices (dielectric spheres immersed in magnetized plasma background or vice versa) are theoretically deduced. The influences of dielectric constant, plasma collision frequency, filling factor, the external magnetic field, and plasma frequency on the dispersive properties for both types of structures are studied in detail, respectively, and some corresponding physical explanations are also given. From the numerical results, it has been shown that the photonic band gaps (PBGs) for both types of MPPCs can be manipulated by plasma frequency, filling factor, the external magnetic field, and the relative dielectric constant of dielectric, respectively. Especially, the external magnetic field can enlarge the PBG for type-2 structure (plasma spheres immersed in dielectric background). However, the plasma collision frequency has no effect on the dispersive properties of two types of three-dimensional MPPCs. The locations of flatbands regions for both types of structures cannot be tuned by any parameters except for plasma frequency and the external magnetic field. The analytical results may be informative and of technical use to design the MPPCs devices.

Zhang HaiFeng [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Nanjing Artillery Academy, Nanjing 211132 (China); Liu Shaobin; Yang Huan [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Kong Xiangkun [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Jiangsu Key Laboratory of Meteorological Observation and Information Processing, Nanjing University of Information Science and Technology, Nanjing 210044 (China)

2013-03-15T23:59:59.000Z

102

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

103

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

E-Print Network [OSTI]

mode-locking. The concentric tube arrangement makes DWNTs an interesting class of nanomaterials, with a wide-ranging potential applications, including in (opto)electronics.52-54 Of particular interest relevant to this work, DWNTs also exhibit ultrafast... .; Ferrari, A. C., in Molecular- and Nano-Tubes, (Eds: Hayden, O., Nielsch, K.), Springer US, 2011. [43] Bonaccorso, F.; Sun, Z.; Hasan, T.; Ferrari, A. C. Graphene Photonics and Optoelectronics. Nat. Photon. 2010, 4, 611-622. [44] Boyd, R. W., Nonlinear...

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

104

Fabry-Perot tuning of the band-gap polarity in plasmonic crystals Jin E. Kihm,1 Y. C. Yoon,1 D. J. Park,1 Y. H. Ahn,1 C. Ropers,2 C. Lienau,2,3 J. Kim,4 Q. H. Park,5 and D. S. Kim1,  

E-Print Network [OSTI]

-resolved transmission spectra of nanoslit arrays in metal films demonstrate band-gap formation resulting from surface-gap flipping. Our results indicate an interesting route towards band-gap engineering in plasmonic crystals. DOI of electronic and photonic band gaps--i.e., energy regions with a vanishing density of states in crystal- line

Peinke, Joachim

105

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

106

Parallel particle swarm optimization and finite-difference time-domain (PSO/FDTD) algorithm for multiband and wide-band patch antenna designs  

E-Print Network [OSTI]

rectangular u-slot microstrip patch antennas,” IEEE Trans.Samii, “Wide-band E-shaped patch antennas for wirelessand T. S. Bird, “E-shaped patch antennas for high- speed

Jin, N B; Rahmat-Samii, Y

2005-01-01T23:59:59.000Z

107

Band gap engineering of In{sub 2}O{sub 3} by alloying with Tl{sub 2}O{sub 3}  

SciTech Connect (OSTI)

Efficient modulation of the bandgap of In{sub 2}O{sub 3} will open up a route to improved electronic properties. We demonstrate using ab initio calculations that Tl incorporation into In{sub 2}O{sub 3} reduces the band gap and confirm that narrowing of the gap is observed by X-ray photoemission spectroscopy on ceramic surfaces. Incorporation of Tl does not break the symmetry of the allowed optical transitions, meaning that the doped thin films should retain optical transparency in the visible region, in combination with a lowering of the conduction band effective mass. We propose that Tl-doping may be an efficient way to increase the dopability and carrier mobility of In{sub 2}O{sub 3}.

Scanlon, David O., E-mail: d.scanlon@ucl.ac.uk [Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Regoutz, Anna; Egdell, Russell G. [Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom)] [Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom); Morgan, David J. [Cardiff Catalysis Institute (CCI), School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT (United Kingdom)] [Cardiff Catalysis Institute (CCI), School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT (United Kingdom); Watson, Graeme W. [School of Chemistry and CRANN, Trinity College Dublin, Dublin 2 (Ireland)] [School of Chemistry and CRANN, Trinity College Dublin, Dublin 2 (Ireland)

2013-12-23T23:59:59.000Z

108

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

109

Importance of carrier dynamics and conservation of momentum in atom-selective STM imaging and band gap determination of GaAs(110)  

Science Journals Connector (OSTI)

Scanning tunneling microscopy and spectroscopy measurements on the GaAs(110) surface with complementary theoretical calculations are performed to clarify the effects involved in the tunneling of unpinned semiconductor surfaces. We show that the flatband and tip-induced band bending as well as equilibrium conditions are insufficient to describe the effects involved. Instead, carrier dynamics and conservation of momentum of the tunneling electrons need to be taken into account for a complete description of the contributions of the valence or conduction band states. The results allow us to understand the unique properties needed to achieve the atom-selective imaging observed on these surfaces as well as the determination of the band gap energy.

N. D. Jäger, E. R. Weber, K. Urban, and Ph. Ebert

2003-04-29T23:59:59.000Z

110

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

E-Print Network [OSTI]

limited to 6 % in Cu2Te/CdTe junctions [4, 5], 7.9 % in CdS/CdTe heterojunctions and 6 % in homojunc with uniform doping followed by a base region with uni- form gap and doping. Our goal is to find the optimum

Boyer, Edmond

111

Low-band-gap, amorphous-silicon-based alloys by photochemical vapor deposition: Final report, 1 October 1985--30 November 1986  

SciTech Connect (OSTI)

Thin films of hydrogenated amorphous silicon-germanium alloys were deposited by mercury-sensitized photochemical vapor deposition using a novel photo-CVD reactor. Thin films of a-Si/sub 1-x/Ge/sub x/:H with 0 less than or equal to x less than or equal to 1 and 1.0 less than E/sub g/ less than 1.8 eV were deposited from mixtures of silane and disilane with germane and inert gas diluents at substrate temperatures from 160/degree/ to 200/degree/C. Alloy films were characterized by measurements of photo- and dark conductivity, electron mobility-lifetime product, sub-band-gap absorption, and density of states. Dilution with hydrogen increased the photoconductivity to 10/sup /minus/5/ Scm and mobility-lifetime product to 6 /times/ 10/sup /minus/8/ cm/sup 2/V for alloys having a band gap of 1.4 eV.

Baron, B.N.; Hegedus, S.S.; Jackson, S.C.

1988-02-01T23:59:59.000Z

112

Low-band-gap, amorphous-silicon-based alloys by chemical vapor deposition: Annual subcontract report, 1 October 1985-31 January 1986  

SciTech Connect (OSTI)

This research was conducted to determine the potential of photochemical vapor deposition (photo-CVD) for producing high-quality, low-band-gap amorphous silicon germanium alloys for use in high-efficiency, multijunction, thin-film photovoltaic solar cells. A photo-CVD reactor for mercury-sensitized photolysis of silane-germane and disilane-germane mixtures was developed. Alloy thin films of undoped a-Si/sub 1-x/Ge/sub x/:H were deposited using mercury vapor mixed with SiH/sub 4/ or Si/sub 2/H/sub 6/, GeH/sub 4/, and diluent gas of Ar, He, or H/sub 2/. Materials properties were characterized by measurements of Ge content, optical transmission and reflection, and dark and photo-conductivity. Opto-electronic properties of photo-CVD a-Si/sub 1-x/Ge/sub x/:H were found to be comparable to glow discharge and sputtered materials. Moreover, p-i-n solar cells with low-band-gap i-layers were able to be fabricated by photo-CVD.

Baron, B.N.; Jackson, S.C.

1986-12-01T23:59:59.000Z

113

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

114

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

115

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

116

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

117

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

118

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

119

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

120

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

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,
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to obtain the most current and comprehensive results.


121

Independent and correlated composition behavior of material properties:?Application to energy band gaps for the Ga?In1-?P?As1-? and Ga?In1-?P?Sb?As1-?-? alloys  

Science Journals Connector (OSTI)

A correlated function expansion (CFE) is introduced (a) to identify the role of independent and correlated composition variations upon a desired material property, and (b) to provide an efficient means to compute the property throughout the composition space. As an example the contributions of independent and correlated composition behavior upon the principal energy band gaps for the alloys Ga?In1-?P?As1-? and Ga?In1-?P?Sb?As1-?-? are calculated and analyzed by applying the CFE to the universal tight-binding (UTB) Hamiltonian model of the alloys. The convergence properties of the CFE over the entire composition variable space (?,?,?) are examined upon including independent, pair-, and triple-correlated terms. By retaining only independent component contributions in the CFE it was possible to represent the UTB results to better than 90% accuracy for both the alloys Ga?In1-?P?As1-? and Ga?In1-?P?Sb?As1-?-?. Pair composition correlations contributed approximately 5–10 % to the band gaps in both alloys and for Ga?In1-?P?Sb?As1-?-? the triple correlations were at the level of ?3%. The CFE is a generic tool capable of simplifying efforts at finding desired alloy compositions for material properties.

Kyurhee Shim and Herschel Rabitz

1998-07-15T23:59:59.000Z

122

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

123

Electronic and crystalline structures of zero band-gap LuPdBi thin films grown epitaxially on MgO(100)  

SciTech Connect (OSTI)

Thin films of the proposed topological insulator LuPdBi-a Heusler compound with the C1{sub b} structure-were prepared on Ta-Mo-buffered MgO(100) substrates by co-sputtering from PdBi{sub 2} and Lu targets. Epitaxial growth of LuPdBi films was confirmed by X-ray diffraction and reflection high-energy electron diffraction. The root-mean-square roughness of the films was as low as 1.45 nm, even though the films were deposited at high temperature. The film composition is close to the ideal stoichiometric ratio. The valence band spectra of the LuPdBi films, observed by hard X-ray photoelectron spectroscopy, correspond very well with the ab initio-calculated density of states.

Shan, Rong [Institut fuer Anorganische und Analytische Chemie, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany) [Institut fuer Anorganische und Analytische Chemie, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany); IBM Almaden Research Center, San Jose, California 95120 (United States); Ouardi, Siham; Fecher, Gerhard H.; ViolBarbosa, Carlos E.; Felser, Claudia [Max Planck Institute for Chemical Physics of Solids, 01187 Dresden (Germany)] [Max Planck Institute for Chemical Physics of Solids, 01187 Dresden (Germany); Gao, Li; Kellock, Andrew; Roche, Kevin P.; Samant, Mahesh G.; Parkin, Stuart S. P. [IBM Almaden Research Center, San Jose, California 95120 (United States)] [IBM Almaden Research Center, San Jose, California 95120 (United States); Ikenaga, Eiji [Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Hyogo 679-5198 (Japan)] [Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Hyogo 679-5198 (Japan)

2013-04-29T23:59:59.000Z

124

Electron Band Structure of Solid Methane: Ab Initio Calculations  

Science Journals Connector (OSTI)

The band structure of crystalline methane has been calculated in a linear-combination-of-molecular-orbitals approximation. In this molecular tight-binding method the Bloch sums are built up of Hartree-Fock orbitals of the free molecules. Interactions between the states of different molecules are calculated directly from molecular integrals without reducing the exchange interaction to an exchange potential. The approximations involved are shown to be well justified for a crystal made of closed-shell units. The band structure is obtained by solving secular equation in 400 points along the relevant symmetry lines. The calculated bands are relatively narrow, less than 2.5 eV wide, around the molecular levels. The band-to-band gap in solid methane is 24.5 eV. This value has the same order of magnitude as in solid rare gases.

Lucjan Piela; Luciano Pietronero; Raffaele Resta

1973-06-15T23:59:59.000Z

125

Planar graphene-narrow-gap semiconductor-graphene heterostructure  

Science Journals Connector (OSTI)

A planar heterostructure composed of two graphene films between which a narrow-gap semiconductor ... paradox is absent when conical points of the graphene Brillouin zone are in the band gap...

P. V. Ratnikov; A. P. Silin

2008-11-01T23:59:59.000Z

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

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

128

Domain Walls in Gapped Graphene  

Science Journals Connector (OSTI)

The electronic properties of a particular class of domain walls in gapped graphene are investigated. We show that they can support midgap states which are localized in the vicinity of the domain wall and propagate along its length. With a finite density of domain walls, these states can alter the electronic properties of gapped graphene significantly. If the midgap band is partially filled, the domain wall can behave like a one-dimensional metal embedded in a semiconductor and could potentially be used as a single-channel quantum wire.

G. W. Semenoff; V. Semenoff; Fei Zhou

2008-08-21T23:59:59.000Z

129

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.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1996-01-01T23:59:59.000Z

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.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1994-01-01T23:59:59.000Z

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 figs.

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

1996-06-11T23:59:59.000Z

132

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

133

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

134

ROSAT wide field camera mirrors  

Science Journals Connector (OSTI)

The ROSAT wide field camera (WFC) is an XUV telescope operating in the 12–250-eV energy band. The mirror system utilizes Wolter-Schwarzschild type I (WS I) grazing incidence optics...

Willingale, R

1988-01-01T23:59:59.000Z

135

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,...

136

Bird Banding  

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

Bird Banding Bird Banding Name: Matthew Location: N/A Country: N/A Date: N/A Question: I am researching why the US fish and wildlife agency bands ducks and what information is used to set hunting daily and possession limits. Replies: Matt, The USFW service has been doing this for decades to have statistical data on the population fluctuations of all birds. This information serves to warn when over hunting has taken a toll on a species or if a species is declining due to habitat loss or whatever. This information also indicates need for increased habitat areas as well as possible hunting restrictions. This organization has a formula for setting hunting limits based upon the data received from banding. It is important that all hunters return these bands for they are the ones who will suffer if the information is not there. Females of any species are the most important for reproduction and often they are protected over the males. This should explain the differences in what can be bagged.

137

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...

138

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

139

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

140

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

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

Large half-metallic gap in ferromagnetic semi-Heusler alloys CoCrP and CoCrAs  

SciTech Connect (OSTI)

We investigate the electronic structure and magnetism of semi-Heusler alloys CoCrP and CoCrAs using the full-potential linearized augmented plane wave method. The calculations reveal that CoCrP and CoCrAs are half-metallic (HM) ferromagnets with the same magnetic moment of 2.00 {mu}{sub B} per formula unit. Both alloys have large half-metallic gaps (up to 0.50 eV) and wide band gaps (above 1 eV). The half-metallicity of CoCrP and CoCrAs can be retained even when their lattice constants are changed by -4.8% to 6.6% and -7.7% to 4.5%, respectively. The two alloys show great promise in the applications of spin valve and magnetic tunnel junction.

Yao Zhongyu [School of Physics and Electronic Engineering, Hainan Normal University, Haikou 571158 (China); Zhang, Y. S. [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Yao, K. L. [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); International Center of Materials Physics, Chinese Academy of Science, Shenyang 110015 (China)

2012-08-06T23:59:59.000Z

142

Band-structure analysis from photoreflectance spectroscopy in (Ga,Mn)As  

SciTech Connect (OSTI)

Modulation photoreflectance spectroscopy has been applied to study the band-structure evolution in (Ga,Mn)As epitaxial layers with increasing Mn content. Structural and magnetic properties of the layers were characterized with high-resolution X-ray diffractometry and SQUID magnetometery, respectively. The revealed results of decrease in the band-gap-transition energy in the (Ga,Mn)As layers with increasing Mn content are interpreted in terms of a disordered valence band, extended within the band gap, formed, in highly Mn-doped (Ga,Mn)As, as a result of merging the Mn-related impurity band with the host GaAs valence band.

Yastrubchak, Oksana; Gluba, Lukasz; Zuk, Jerzy [Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin (Poland); Wosinski, Tadeusz; Andrearczyk, Tomasz; Domagala, Jaroslaw Z. [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw (Poland); Sadowski, Janusz [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw, Poland and MAX-Lab, Lund University, 22100 Lund (Sweden)

2013-12-04T23:59:59.000Z

143

Windy Gap Firming Project  

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

Windy Gap Firming Project Windy Gap Firming Project Skip Navigation Links Transmission Functions Infrastructure projects Interconnection OASIS OATT Windy Gap Firming Project, Final Environmental Impact Statement, DOE/EIS-0370 (cooperating agency) Western's proposed action is to relocate approximately 3.8 miles of the existing Estes to Lyons 115-kilovolt transmission line, if the Chimney Hollow Reservoir alternative is constructed. The line would be moved outside the area proposed for the reservoir, and Western would ensure the new location would allow the agency to continue to operate and maintain it. Section 2.4.1.4 of the Final Environmental Impact Statement, Volume 1 provides more information on the transmission line relocation proposal. The U.S. Department of the Interior, Bureau of Reclamation is the Lead Agency for the National Environmental Policy Act Review. Cooperating agencies are Western, the U.S. Army Corps of Engineers and Grand County, Colo.

144

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

2011-07-27T23:59:59.000Z

145

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

146

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

147

A Simple Method of Producing Wide-Band Frequency Modulation  

Science Journals Connector (OSTI)

... THE resistance-capacity tuned oscillator is well known as a very good generator of audio-frequency oscillations. In a recent communication by Rakshit and Bhattacharyya1 it was pointed out ... out that the conventional circuit of a three-phase system, with components selected for producing audio-frequency oscillations, invariably generates radio-frequencies by virtue of the unavoidable stray and inter- ...

H. RAKSHIT; N. SARKAR

1949-04-09T23:59:59.000Z

148

Product Design in Enterprise Wide Optimization  

E-Print Network [OSTI]

Product Design in Enterprise Wide Optimization Paul Arch, Michel Berghmans, Hany Farag NOVA · Simulation tools ­ Polymers/Plus ­ process modeling ­ Predici ­ reactor modeling ­ Gap analysis of commercial + M Dn + P1 Termination by combination Pn + Pm Dn+m Reactor model modified to resemble additional

Grossmann, Ignacio E.

149

Pseudogap and Superconducting Gap in High-Temperature Superconductors  

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

Pseudogap and Superconducting Gap in Pseudogap and Superconducting Gap in High-Temperature Superconductors Two decades after the discovery of first high temperature superconductors, the microscopic mechanism of high-Tc superconductivity remains elusive. In conventional superconductors, it has been well established that electrons form so-called "Cooper pairs" to give rise to superconductivity. The pair binding manifests itself as an energy gap in many spectroscopic measurements. This energy gap, known as superconducting gap, appears at the superconducting transition temperature Tc where the resistance also vanishes. For high temperature superconductors, the story is more complicated. Over a wide region of compositions and temperatures, there exists an energy gap well above Tc. This energy gap is called pseudogap [1], because there is no direct correlation to the superconducting transition. The origin of this pseudogap and its relation to the superconducting gap are believed to hold the key for understanding the mechanism of high-Tc superconductivity - one of the outstanding problems in condensed matter physics. In this regard, researchers Kiyohisa Tanaka and Wei-Sheng Lee, along with their co-workers in Prof. Zhi-Xun Shen's group at Stanford University, have recently made an important discovery about the coexistence of two distinct energy gaps that have opposite doping dependence. Their observation not only provides a natural explanation for the contradictory results about the superconducting gap deduced from different experimental techniques, but also has profound implications on the mechanism of high-Tc superconductivity.

150

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

151

British wind band music.  

E-Print Network [OSTI]

??I have chosen to be assessed as an interpreter and conductor of British wind band music from the earliest writings for wind band up to,… (more)

Jones, GO

2005-01-01T23:59:59.000Z

152

Magneto-transport properties of gapped graphene  

Science Journals Connector (OSTI)

Based on the Kubo formula, we have studied the electron transport properties of a gapped graphene in the presence of a strong magnetic field. By solving the Dirac equation, we find that the Landau level spectra in two valleys differ from each other in that the n = 0 level in the K valley is located at top of the valence band, whereas it is at the bottom of the conduction band in the K' valley. Thus, in an individual valley, the symmetry between conduction and valence bands is broken by the presence of a magnetic field. By using the self-consistent Born approximation to treat the long range potential scattering, we formulate the diagonal and the Hall conductivities in terms of the Green function. To perform the numerical calculation, we find that a large bandgap can suppress the quantum Hall effect, owing to the enhancement of the bandgap squeezing the spacing between the low-lying Landau levels. On the other hand, if the bandgap is not very large, the odd integer quantum Hall effect experimentally, observed in the gapless graphene, remains in the gapped one. However, such a result does not indicate the half integer quantum Hall effect in an individual valley of the gapped graphene. This is because the heights of the Hall plateaux in either valley can be continuously tuned by the variation of the bandgap. More interestingly, we find that the height of the diagonal conductivity peak corresponding to the n = 0 Landau level is independent of the bandgap if the scattering is not very strong. In the weak scattering limit, we demonstrate analytically that such a peak takes a universal value e2/(h?), regardless of the bandgap.

Liwei Jiang; Yisong Zheng; Haidong Li; Honghai Shen

2010-01-01T23:59:59.000Z

153

Colorado Gap Analysis  

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

Colorado Gap Analysis Colorado Gap Analysis 2 The Building Codes Assistance Project (BCAP) BCAP is a non-profit advocacy organization established in 1994 as a joint initiative of the Alliance to Save Energy, the American Council for an Energy-Efficient Economy, and the Natural Resources Defense Council. BCAP focuses on providing state and local governments in the U.S., as well as stakeholder organizations, with support on code adoption and implementation through direct assistance, research, data analysis, and coordination with other activities and allies. With over sixteen years of experience supporting numerous state energy offices and city building departments, along with tracking code activities across the country, BCAP is well-positioned to assist in local and statewide activity to advance

154

Nanodopant-Induced Band Modulation in AgPbmSbTe2+m-Type Nanocomposites  

SciTech Connect (OSTI)

We elucidate the fundamental physics of nanoscale dopants in narrow band-gap thermoelectric nanocomposites XPbmYTe2+m (X=Ag,Na; Y=Sb,Bi) using first-principles calculations. Our re- sults unveil distinct band-structure modulations, most notably a sizable band-gap widening driven by nanodopant-induced lattice strain and a band split-off at the conduction band minimum caused by the spin-orbit interaction of the dopant Sb or Bi atoms. Boltzmann transport calculations demon- strate that these band modulations have significant but competing effects on high-temperature elec- tron transport behavior. These results offer insights for understanding recent experimental findings and suggest principles for optimizing thermoelectric properties of narrow band-gap semiconductors.

Zhang, Yi [University of Nevada, Las Vegas; Ke, Xuezhi [University of Nevada, Las Vegas; Chen, Changfeng [University of Nevada, Las Vegas; Yang, Jihui [General Motors Corporation-R& D; Kent, Paul R [ORNL

2011-01-01T23:59:59.000Z

155

Energy Gap in Nuclear Matter  

Science Journals Connector (OSTI)

......research-article Articles Energy Gap in Nuclear Matter Takeshi Ishihara a...Research, Kokubunji, Tokyo An energy gap in nuclear matter is studied. The nucleon-nucleon...1966) pp. 1026-1042 Nuclear Force and Energy Gap in Finite Nuclei Hiroharu......

Takeshi Ishihara; Ryozo Tamagaki; Hajime Tanaka; Masaru Yasuno

1963-11-01T23:59:59.000Z

156

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

157

GenII Gap Analysis  

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

GENII-Gap Analysis GENII-Gap Analysis Defense Nuclear Facilities Safety Board Recommendation 2002-1 Software Quality Assurance Improvement Plan Commitment 4.2.1.3: Software Quality Assurance Improvement Plan: GENII Gap Analysis Final Report U.S. Department of Energy Office of Environment, Safety, and Health 1000 Independence Ave., S.W. Washington, DC 20585-2040 May 2004 GENII Gap Analysis May 2004 Final Report INTENTIONALLY BLANK ii GENII Gap Analysis May 2004 Final Report FOREWORD This document provides an evaluation of the Software Quality Assurance (SQA) attributes of GENII, a radiological dispersion computer code, relative to established requirements. This evaluation, a "gap analysis", is performed to meet commitment 4.2.1.3 of the Department of

158

MACCS2 Final Gap Analysis  

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

MACCS2-Gap Analysis MACCS2-Gap Analysis Defense Nuclear Facilities Safety Board Recommendation 2002-1 Software Quality Assurance Improvement Plan Commitment 4.2.1.3: Software Quality Assurance Improvement Plan: MACCS2 Gap Analysis Final Report U.S. Department of Energy Office of Environment, Safety and Health 1000 Independence Ave., S.W. Washington, DC 20585-2040 May 2004 MACCS2 Gap Analysis May 2004 Final Report INTENTIONALLY BLANK ii MACCS2 Gap Analysis May 2004 Final Report FOREWORD This report documents the outcome of an evaluation of the Software Quality Assurance (SQA) attributes of the radiological dispersion computer code, MACCS2, relative to established software requirements. This evaluation, a "gap analysis", is performed to meet commitment 4.2.1.3 of the

159

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

160

Bridging the Gaps of High-Tc Superconductor  

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

Bridging the Gaps of High-Tc Bridging the Gaps of High-Tc Superconductor Since the discovery of high-temperature superconductor by Bednorz and Müller in 1986, this field has become one of the most important research topics in solid state physics. In the past 20 years many unconventional properties have been discovered in this new class of materials. These have challenged our conventional wisdom and driven the development of many novel theories. Among these discoveries, the most mysterious is probably the pseudogap phenomena: it has been observed that there is an energy gap above the superconducting transition temperature (TC) that persists over a wide range of temperatures and chemical compositions [1]. This peculiar behavior appears to be very different from a conventional superconductor. Here the electrons form so-called "Cooper pairs", which manifests itself as an energy gap in many spectroscopic measurements. This energy gap, known as superconducting gap, appears only below TC where the electrical resistance also vanishes (hence the name 'superconductor'). This important difference has stimulated lots of debate in the search of understanding high-TC superconductivity on questions such as: "What is the pseudogap?" and "What is its relation to superconducting gap and superconductivity at high temperature?"

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

World Wide Chemistry  

Science Journals Connector (OSTI)

World Wide Chemistry ... Plutonium has been produced for the first time at Britain's Atomic Energy Research Establishment at Harwell. ... Indian Ore Reserves ...

G. ABRAHAMSON; RAFFAELE SANSONE

1949-04-11T23:59:59.000Z

162

Photoelectrochemical Study of the Band Structure of Zn2SnO4 Prepared by the Hydrothermal Method  

Science Journals Connector (OSTI)

In this paper, we study the band gap (Eg) and energetics of the conduction band (CB) and valence band (VB) for films of zinc stannate (Zn2SnO4) nanoparticles (ca. 25 nm) of the inverse-spinel structure prepared by the hydrothermal method. ...

Mario A. Alpuche-Aviles; Yiying Wu

2009-02-16T23:59:59.000Z

163

Pneumatic gap sensor and method  

DOE Patents [OSTI]

An apparatus and method for monitoring and maintaining a predetermined width in the gap between a casting nozzle and a casting wheel, wherein the gap is monitored by means of at least one pneumatic gap sensor. The pneumatic gap sensor is mounted on the casting nozzle in proximity to the casting surface and is connected by means of a tube to a regulator and a transducer. The regulator provides a flow of gas through a restictor to the pneumatic gap sensor, and the transducer translates the changes in the gas pressure caused by the proximity of the casting wheel to the pneumatic gap sensor outlet into a signal intelligible to a control device. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. The apparatus and method enables accurate monitoring of the actual casting gap in a simple and reliable manner resistant to the extreme temperatures and otherwise hostile casting environment.

Bagdal, Karl T. (Middletown, OH); King, Edward L. (Trenton, OH); Follstaedt, Donald W. (Middletown, OH)

1992-01-01T23:59:59.000Z

164

INFOGRAPHIC: Wide Bandgap Semiconductors  

Office of Energy Efficiency and Renewable Energy (EERE)

Breakthrough material technology called wide bandgap (WBG) semiconductors can help reduce the amount of wasted heat, boost energy efficiency, improve reliability, reduce cost, and decrease system size in existing and future power electronics.

165

the World Wide Web  

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

technical report has been made electronically available on the World Wide Web through a contribution from Walter L. Warnick In honor of Enrico Fermi Leader of the first nuclear...

166

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

167

Band structure properties of (BGa)P semiconductors for lattice matched integration on (001) silicon  

SciTech Connect (OSTI)

We report the band structure properties of (BGa)P layers grown on silicon substrate using metal-organic vapour-phase epitaxy. Using surface photo-voltage spectroscopy we find that both the direct and indirect band gaps of (BGa)P alloys (strained and unstrained) decrease with Boron content. Our experimental results suggest that the band gap of (BGa)P layers up to 6% Boron is large and suitable to be used as cladding and contact layers in GaP-based quantum well heterostructures on silicon substrates.

Hossain, Nadir; Sweeney, Stephen [Advanced Technology Institute and Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Hosea, Jeff [Advanced Technology Institute and Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, UK and Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, Johor Bahru 81310 (Malaysia); Liebich, Sven; Zimprich, Martin; Volz, Kerstin; Stolz, Wolfgang [Material Sciences Center and Faculty of Physics, Philipps-University, 35032 Marburg (Germany); Kunert, Bernerdette [NAsP III/V GmbH, Am Knechtacker 19, 35041 Marburg (Germany)

2013-12-04T23:59:59.000Z

168

Broad-band beam buncher  

DOE Patents [OSTI]

A broad-band beam bunther 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-

Goldberg, D.A.; Flood, W.S.; Arthur, A.A.; Voelker, F.

1984-03-20T23:59:59.000Z

169

Eight-band k?p model of strained zinc-blende crystals  

Science Journals Connector (OSTI)

Second-order Löwdin perturbation theory is used to calculate the interaction matrices for an eight-band k?p model (near the ? point) of zinc-blende crystals under a uniform strain. The model treats the ?6 conduction bands, ?8 valence bands, and ?7 spin-orbit split-off bands. The model includes strain interactions arising from both the orbital and spin-orbit terms of the Hamiltonian. In addition to the usual Pikus-Bir deformation-potential constants, a, b, and d, which describe the coupling of the valence band to strain, two new deformation-potential constants arise, a’ and b’, which describe the coupling of the conduction band to strain. The constant a’ couples the conduction band to hydrostatic deformations and the constant b’, which results from a lack of inversion symmetry, couples the conduction band to shear deformations. The strain also introduces a k-dependent conduction-band–valence-band mixing that is linear in strain, in wave vector, and in the momentum matrix element between the conduction and valence bands. In the absence of strain, the eight-band Kane model is recovered. Under a finite strain, in the limit of a large conduction-band–valence-band gap and large spin-orbit splitting, the four-band Luttinger model with strain is recovered.

Thomas B. Bahder

1990-06-15T23:59:59.000Z

170

Bridging Gaps | Department of Energy  

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

Bridging Gaps Bridging Gaps Bridging Gaps Analysis to identify issues, best practices, and recommendations Implementation of modernization, infrastructure planning, and sustainability efforts Evaluation of planning practices to develop an adaptable method that considers revitalization and reuse Analysis of issues with transfers at less than fair market value and recommendations for improvement Evaluation of the Ten-Year (25-year) Site Plans for revitalization and strategic planning interests Tools to be incorporated into programmatic business models and processes Best-practices guide for energy projects Guidance and recommendations to improve the 10 CFR 770 process and less-than-fair-market-value transfers Tools/checklist to evaluate assets for reuse as part of planning

171

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

172

Energy Gap in Nuclear Matter  

Science Journals Connector (OSTI)

The magnitude of the energy gap in nuclear matter associated with a highly correlated ground state of of the type believed to be important in the theory of superconductivity has been evaluated theoretically. The integral equation of Cooper, Mills, and Sessler is linearized and transformed into a form suitable for numerical solution. The energy gap, calculated by using an appropriate single-particle potential and the Gammel-Thaler two-body potential, is found to be a very strong function of the density of nuclear matter, and of the effective mass at the Fermi surface. It is concluded that the magnitude of the energy gap for nuclear matter should not be compared directly with experimental values for finite nuclei, although the results suggest that if the theory is extended to apply to finite nuclei it probably would be in agreement with experiment.

V. J. Emery and A. M. Sessler

1960-07-01T23:59:59.000Z

173

Local Energy Gap in Deformed Carbon Nanotubes  

Science Journals Connector (OSTI)

......Local Energy Gap in Deformed Carbon Nanotubes Ken-ichi Sasaki 1 *) Yoshiyuki...gap along the axis of a deformed nanotube. We compare our energy gap results...experimental data on energy gaps in nanotubes and peapods. We also discuss the......

Ken-ichi Sasaki; Yoshiyuki Kawazoe; Riichiro Saito

2005-03-01T23:59:59.000Z

174

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

175

Efficient periodic band diagram computation using a finite element method, Arnoldi eigensolver and sparse linear system solver  

E-Print Network [OSTI]

We present here a Finite Element Method devoted to the simulation of 3D periodic structures of arbitrary geometry. The numerical method based on ARPACK and PARDISO libraries, is discussed with the aim of extracting the eigenmodes of periodical structures and thus establishing their frequency band gaps. Simulation parameters and the computational optimization are the focus. Resolution will be used to characterize EBG (Electromagnetic Band Gap) structures, such as plasma rods and metallic cubes.

Garnier, Romain; Pascal, Olivier

2014-01-01T23:59:59.000Z

176

General Formulation for the Calibration and Characterization of Narrow-gap Etalons: the OSIRIS/GTC Tunable Filters Case  

E-Print Network [OSTI]

Tunable filters are a powerful way of implementing narrow-band imaging mode over wide wavelength ranges, without the need of purchasing a large number of narrow-band filters covering all strong emission or absorption lines at any redshift. However, one of its main features is a wavelength variation across the field of view, sometimes termed the phase effect. In this work, an anomalous phase effect is reported and characterized for the OSIRIS instrument at the 10.4m Gran Telescopio Canarias. The transmitted wavelength across the field of view of the instrument depends, not only on the distance to the optical centre, but on wavelength. This effect is calibrated for the red tunable filter of OSIRIS by measuring both normal-incidence light at laboratory and spectral lamps at the telescope at non-normal incidence. This effect can be explained by taking into account the inner coatings of the etalon. In a high spectral resolution etalon, the gap between plates is much larger than the thickness of the inner reflectiv...

Gonzalez, J J; Gonzalez-Serrano, J I; Sanchez-Portal, M

2014-01-01T23:59:59.000Z

177

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

178

Temperature dependent band offsets in PbSe/PbEuSe quantum well heterostructures  

SciTech Connect (OSTI)

The band offsets of PbSe/Pb{sub 1-x}Eu{sub x}Se multi-quantum wells grown by molecular beam epitaxy are determined as a function of temperature and europium content using temperature-modulated differential transmission spectroscopy. The confined quantum well states in the valence and conduction bands are analyzed using a k{center_dot}p model with envelope function approximation. From the fit of the experimental data, the normalized conduction band offset is determined as 0.45{+-}0.15 of the band gap difference, independently of Eu content up to 14% and temperature from 20 to 300 K.

Simma, M.; Bauer, G.; Springholz, G. [Institut fuer Halbleiter und Festkoerperphysik, Johannes Kepler Universitaet, A-4040 Linz (Austria)

2012-10-22T23:59:59.000Z

179

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

180

Visitors Far and Wide  

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

4 4 Visitors Far and Wide From left: Minister Danilov-Daniljan, Evan Mills (Assistant Director, Center for Building Science), Victoria Mats (interpreter and Soviet energy analyst), and Len Grossman (PG&E Energy Center) tour the PG&E Energy Center in San Francisco. The Russian Minister of Ecology and Natural Resources, Victor I. Danilov-Daniljan, spent three days in California as the Center's guest. The Minister presented information on current Soviet energy and environmental dilemmas and participated in a day-long roundtable discussion with representatives of major utilities, manufacturers of energy-efficient technologies, energy regulators, nongovernmental organizations, and Center scientists. Julian Aizenberg, one of the former Soviet Union's (FSU) foremost lighting

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.


181

Island Wide Management Corporation  

Office of Legacy Management (LM)

9 1986 9 1986 Island Wide Management Corporation 3000 Marcus Avenue Lake Success, New York 11042 Dear Sir or Madam: I am sending you this letter and the enclosed information as you have been identified by L. I. Trinin of Glick Construction Company as the representatives of the owners of the property that was formerly the site of the Sylvania-Corning Nuclear Corporation in Bayside, New York. The Department of Energy is evaluating the radiological condition of sites that were utilized under the Manhattan Engineer District and/or the Atomic Energy Commission in the early years of nuclear energy development to determine whether they need remedial action and whether the Department has authority to perform such action. As you may know, the former Sylvania-Corning Corporation Bayside site was identified as one such site.

182

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

183

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

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

Scanning tunneling microscopy on unpinned GaN(11¯00) surfaces: Invisibility of valence-band states  

Science Journals Connector (OSTI)

We investigated the origins of the tunnel current in scanning tunneling microscopy (STM) and spectroscopy experiments on GaN(11¯00) surfaces. By calculating the tunnel currents in the presence of a tip-induced band bending for unpinned n-type GaN(11¯00) surfaces, we demonstrate that only conduction-band states are observed at positive and negative voltage polarities independent of the doping concentration. Valence-band states remain undetectable because tunneling out of the electron-accumulation zone in conduction-band states dominates by four orders of magnitude. As a result band-gap sizes cannot be determined by STM on unpinned GaN(11¯00) surfaces. Appropriate band-edge positions and gap sizes can be determined on pinned surfaces.

Ph. Ebert, L. Ivanova, and H. Eisele

2009-08-24T23:59:59.000Z

186

the World Wide Web  

Office of Scientific and Technical Information (OSTI)

technical report has been made technical report has been made electronically available on the World Wide Web through a contribution from Walter L. Warnick In honor of Enrico Fermi Leader of the first nuclear reactor, Nobel Prize winner, and visionary technologist Dr. Warnick is delighted to be the first sponsor for posting a Department of Energy technical report and making it broadly available Office of Scientific and Technical Information Office of Science U.S. Department of Energy September 2008 osti.gov U N I T E D S T A T E S A T O M I C E N E R G Y C O M M I S S I O N AECD-3269 EXPERIMENTAL PRODUCTION OF A DNERGENT CHAIN REACTION BY E. Fermi January 4, 1952 [TIS Issuance ate] [chicago University] - T e c h n i c a l I n f o r m a t i o n S e r v i c e , O a k Ridge, T e n n e s s e e r ABSTRACTS Description of the construction and operation of the chain

187

Genetic-Algorithm Discovery of a Direct-Gap and Optically Allowed Superstructure from Indirect-Gap Si and Ge Semiconductors  

SciTech Connect (OSTI)

Combining two indirect-gap materials - with different electronic and optical gaps - to create a direct gap material represents an ongoing theoretical challenge with potentially rewarding practical implications, such as optoelectronics integration on a single wafer. We provide an unexpected solution to this classic problem, by spatially melding two indirect-gap materials (Si and Ge) into one strongly dipole-allowed direct-gap material. We leverage a combination of genetic algorithms with a pseudopotential Hamiltonian to search through the astronomic number of variants of Si{sub n}/Ge{sub m}/.../Si{sub p}/Ge{sub q} superstructures grown on (001) Si{sub 1-x}Ge{sub x}. The search reveals a robust configurational motif - SiGe{sub 2}Si{sub 2}Ge{sub 2}SiGe{sub n} on (001) Si{sub x}Ge{sub 1-x} substrate (x {le} 0.4) presenting a direct and dipole-allowed gap resulting from an enhanced {Gamma}-X coupling at the band edges.

d'Avezac, M.; Luo, J. W.; Chanier, T.; Zunger, A.

2012-01-13T23:59:59.000Z

188

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

189

Electronic properties of the Ga vacancy in GaP(110) surfaces determined by scanning tunneling microscopy  

Science Journals Connector (OSTI)

The electronic properties of uncharged Ga monovacancies in GaP(110) surfaces are determined from voltage-dependent scanning tunneling microscopy images. The signatures of localized defect states in the band gap are analyzed and their spatial location is determined. Empty and occupied defect states exist. Depressed dangling bonds in the occupied-state images indicate an inward relaxation of the neighboring P atoms. The results agree with recent theoretical work.

Ph. Ebert and K. Urban

1998-07-15T23:59:59.000Z

190

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

191

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

192

Functional Area Qualification Standard Gap Analysis Qualification Cards |  

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

Services » Assistance » Federal Technical Capability Program » Services » Assistance » Federal Technical Capability Program » Functional Area Qualification Standard Gap Analysis Qualification Cards Functional Area Qualification Standard Gap Analysis Qualification Cards Note: 1. Save the document from the website onto your PC and close it. 2. Open the document on your PC. Answer "No" to the question regarding whether to open the documents as read only. Chemical Processing Gap Construction Management Gap Criticality Safety Gap Emergency Management Gap Environmental Restoration Gap Facility Representative Gap Fire Protection Engineering Gap General Technical Base Gap Industrial Hygiene Gap Mechanical Systems Gap Nuclear Explosive Safety Study Gap Nuclear Safety Specialist Gap Occupational Safety Gap Quality Assurance Gap

193

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

194

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

195

Hotspot Gap Analysis Final 20070323  

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

HS-0003 HS-0003 Software Evaluation of Hotspot and DOE Safety Software Toolbox Recommendation U.S. Department of Energy Office of Health, Safety and Security 1000 Independence Avenue, S.W. Washington, DC 20585-2040 March, 2007 ii Foreword This report documents the outcome of an evaluation of the Safety Software Quality Assurance (SSQA) attributes of Hotspot, a health physics application, relative to the safety software requirements identified in DOE O 414.1C, Quality Assurance. This evaluation, a "gap analysis", is performed according to the implementation guide DOE G 414.1-4, and is a requisite for deciding whether Hotspot should be designated as a toolbox code for DOE's safety software Central Registry. Comments regarding this document should be addressed to:

196

Hydrothermal Exploration Data Gap Analysis Update  

Broader source: Energy.gov [DOE]

Hydrothermal Exploration Data Gap Analysis presentation by Kate Young, Dan Getman, and Ariel Esposito at the 2012 Peer Review Meeting on May 10, 2012

197

FAQS Gap Analysis Qualification Card – Occupational 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.

198

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.

199

Effect of nanostructuring on the band structure and the galvanomagnetic properties in Bi{sub 1?x}Sb{sub x} alloys  

SciTech Connect (OSTI)

Magnetotransport measurements were performed on a series of nanostructured Bi{sub 1?x}Sb{sub x} alloy samples with an Sb content in the range between 0% and 60%. The samples were prepared by cold pressing and annealing of crystalline Bi{sub 1?x}Sb{sub x} nanoparticles, which were synthesized by mechanical alloying. The incorporation of Sb changes the band structure of these nanotextured alloys as well as their transport behavior. With increasing Sb content the band gap increases and reaches a maximum band gap of 42?meV at an Sb concentration of about 14% determined from temperature dependent resistivity measurements. For even higher Sb content, the band gap decreases again. The bands and thus the band gaps are shifted with respect to bulk material due to quantum confinement effects in the nanostructures. The change of the band structure with varying Sb content strongly affects the magnetoresistance behavior as well as the magnetic field dependence of the Hall-coefficient. Using a three band model in order to describe both properties, it was possible to determine the main band parameters of the nanostructured material as a function of the Sb content.

Will, C. H.; Elm, M. T., E-mail: matthias.elm@exp1.physik.uni-giessen.de; Klar, P. J. [Institute of Experimental Physics I, Justus-Liebig University, Heinrich-Buff-Ring 16, D-35392 Giessen (Germany); Landschreiber, B.; Güne?, E.; Schlecht, S. [Institute of Inorganic and Analytical Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen (Germany)

2013-11-21T23:59:59.000Z

200

Measurement of valence band structure in arbitrary dielectric films  

SciTech Connect (OSTI)

A new way of measuring the band structure of various dielectric materials using the secondary electron emission from Auger neutralization of ions is introduced. The first example of this measurement scheme is the magnesium oxide (MgO) films with respect to the application of the films in the display industries. The density of state in the valence bands of MgO film and MgO film with a functional layer (FL) deposited over a dielectric surface reveals that the density peak of film with a FL is considerably less than that of film, thereby indicating a better performance of MgO film with functional layer in display devices. The second example of the measurement is the boron-zinc oxide (BZO) films with respect to the application of the films to the development of solar cells. The measurement of density of state in BZO film suggests that a high concentration of boron impurity in BZO films may enhance the transition of electrons and holes through the band gap from the valence to the conduction band in zinc oxide crystals; thereby improving the conductivity of the film. Secondary electron emission by the Auger neutralization of ions is highly instrumental for the determination of the density of states in the valence band of dielectric materials.

Uhm, Han S., E-mail: hsuhm@kw.ac.kr [Department of Electrophysics, Kwangwoon University, 447-1 Wolgye-Dong, Nowon-Gu, Seoul 139-701 (Korea, Republic of); Choi, Eun H. [Department of Electrophysics, Kwangwoon University, 447-1 Wolgye-Dong, Nowon-Gu, Seoul 139-701 (Korea, Republic of)] [Department of Electrophysics, Kwangwoon University, 447-1 Wolgye-Dong, Nowon-Gu, Seoul 139-701 (Korea, Republic of)

2012-10-15T23:59:59.000Z

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.


201

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

202

3+1 dimensional integrated optics with localized light in a photonic band gap  

E-Print Network [OSTI]

," Phys. Rev. Lett. 58, 2486­ 2489 (1987). 3. D. Wiersma, P. Bartolini, A. Lagendijk, and R. Righini

John, Sajeev

203

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

204

Low Band Gap Poly(thienylene vinylene)/Fullerene Bulk Heterojunction Photovoltaic Cells  

Science Journals Connector (OSTI)

This work was funded by the Initiative for Renewable Energy and the Environment (IREE) at the University of Minnesota (UMN) and the Xcel Energy Renewable Development Fund. ...

Jung Yong Kim; Yang Qin; Derek M. Stevens; Ozan Ugurlu; Vivek Kalihari; Marc A. Hillmyer; C. Daniel Frisbie

2009-05-21T23:59:59.000Z

205

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

206

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

207

Development of Low Band Gap Polymers for Roll-to-Roll Coated Polymer Solar Cell Modules  

Science Journals Connector (OSTI)

Organic photovoltaics (OPV) have the potential for low production cost. Additionally, there has been an increase in both efficiency and stability of small-area OPV devices prepared in research laboratories wor...

Eva Bundgaard; Frederik Krebs

2011-01-01T23:59:59.000Z

208

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...

209

Optimizing the Q value in three-dimensional metallic photonic band gap crystals  

E-Print Network [OSTI]

, and for improving solar energy collection.12 The complementary inductive metallic patches are also FSS with a low in the transmission are created by removing portions of the metallic rods in a single defect layer. A high quality composed of material with a high dielectric constant in a lower dielec- tric background such as air

Soukoulis, Costas

210

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

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

Gas mixtures for spark gap closing switches  

DOE Patents [OSTI]

Gas mixtures for use in spark gap closing switches comprised of fluorocarbons and low molecular weight, inert buffer gases. To this can be added a third gas having a low ionization potential relative to the buffer gas. The gas mixtures presented possess properties that optimized the efficiency spark gap closing switches. 6 figs.

Christophorou, L.G.; McCorkle, D.L.; Hunter, S.R.

1987-02-20T23:59:59.000Z

213

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

214

Electronic- and band-structure evolution in low-doped (Ga,Mn)As  

SciTech Connect (OSTI)

Modulation photoreflectance spectroscopy and Raman spectroscopy have been applied to study the electronic- and band-structure evolution in (Ga,Mn)As epitaxial layers with increasing Mn doping in the range of low Mn content, up to 1.2%. Structural and magnetic properties of the layers were characterized with high-resolution X-ray diffractometry and SQUID magnetometery, respectively. The revealed results of decrease in the band-gap-transition energy with increasing Mn content in very low-doped (Ga,Mn)As layers with n-type conductivity are interpreted as a result of merging the Mn-related impurity band with the host GaAs valence band. On the other hand, an increase in the band-gap-transition energy with increasing Mn content in (Ga,Mn)As layers with higher Mn content and p-type conductivity indicates the Moss-Burstein shift of the absorption edge due to the Fermi level location within the valence band, determined by the free-hole concentration. The experimental results are consistent with the valence-band origin of mobile holes mediating ferromagnetic ordering in the (Ga,Mn)As diluted ferromagnetic semiconductor.

Yastrubchak, O.; Gluba, L.; ?uk, J. [Institute of Physics, UMCS, Pl. Marii Curie-Sk?odowskiej 1, 20-031 Lublin (Poland)] [Institute of Physics, UMCS, Pl. Marii Curie-Sk?odowskiej 1, 20-031 Lublin (Poland); Sadowski, J. [Institute of Physics, Polish Academy of Sciences, 02-668 Warszawa (Poland) [Institute of Physics, Polish Academy of Sciences, 02-668 Warszawa (Poland); MAX-Lab, Lund University, 22100 Lund (Sweden); Krzy?anowska, H. [Institute of Physics, UMCS, Pl. Marii Curie-Sk?odowskiej 1, 20-031 Lublin (Poland) [Institute of Physics, UMCS, Pl. Marii Curie-Sk?odowskiej 1, 20-031 Lublin (Poland); Department of Physics and Astronomy, Vanderbilt University, 6506 Stevenson Center, Nashville, Tennessee 37325 (United States); Domagala, J. Z.; Andrearczyk, T.; Wosinski, T. [Institute of Physics, Polish Academy of Sciences, 02-668 Warszawa (Poland)] [Institute of Physics, Polish Academy of Sciences, 02-668 Warszawa (Poland)

2013-08-07T23:59:59.000Z

215

Judith Gap Wind Farm | Open Energy Information  

Open Energy Info (EERE)

Gap Wind Farm Gap Wind Farm Jump to: navigation, search Name Judith Gap Wind Farm Facility Judith Gap Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner Invenergy Developer Invenergy Energy Purchaser Northwestern Energy Location South of Judith Gap MT Coordinates 46.6005°, -109.749° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":46.6005,"lon":-109.749,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

216

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

217

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

218

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

219

Buffalo Gap Wind Farm | Open Energy Information  

Open Energy Info (EERE)

Gap Wind Farm Gap Wind Farm Jump to: navigation, search Name Buffalo Gap Wind Farm Facility Buffalo Gap Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner AES Developer AES Energy Purchaser Direct Energy Location TX Coordinates 32.310556°, -100.149167° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":32.310556,"lon":-100.149167,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

220

Gaps in the Heisenberg-Ising model  

Science Journals Connector (OSTI)

We report on the closing of gaps in the ground state of the critical Heisenberg-Ising chain at momentum ?. For half-filling, the gap closes at special values of the anisotropy ?=cos(?/Q), where Q is an integer. We explain this behavior with the help of the Bethe ansatz and show that the gap scales as a power of the system size with a variable exponent depending on ?. We use a finite-size analysis to calculate this exponent in the critical region, supplemented by perturbation theory at ??0. For rational 1/r fillings, the gap is shown to be closed for all values of ? and the corresponding perturbation expansion in ? shows a remarkable cancellation of various diagrams.

Rudolf A. Römer; Hans-Peter Eckle; Bill Sutherland

1995-07-15T23:59:59.000Z

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.


221

Radioactive Waste Management Complex Wide Review | Department...  

Office of Environmental Management (EM)

Radioactive Waste Management Complex Wide Review Radioactive Waste Management Complex Wide Review The main goal of this complex-wide review was to obtain feedback from DOE sites...

222

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

223

Gap between jets at the LHC  

SciTech Connect (OSTI)

We describe a NLL BFKL calculation implemented in the HERWIG MC of the gap between jets cross section, that represent a test of BFKL dynamics. We compare the predictions with recent measurements at the Tevatron and present predictions for the LHC. We also discuss the interesting process of looking for gap between jets in diffractive events when protons are detected in the ATLAS Forward Physics (AFP) detectors.

Royon, Christophe [CEA/IRFU/Service de physique des particules, CEA/Saclay, 91191 Gif-sur-Yvette cedex (France)

2013-04-15T23:59:59.000Z

224

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

225

Annual Growth Bands in Hymenaea courbaril  

SciTech Connect (OSTI)

One significant source of annual temperature and precipitation data arises from the regular annual secondary growth rings of trees. Several tropical tree species are observed to form regular growth bands that may or may not form annually. Such growth was observed in one stem disk of the tropical legume Hymenaea courbaril near the area of David, Panama. In comparison to annual reference {Delta}{sup 14}C values from wood and air, the {Delta}{sup 14}C values from the secondary growth rings formed by H. courbaril were determined to be annual in nature in this one stem disk specimen. During this study, H. courbaril was also observed to translocate recently produced photosynthate into older growth rings as sapwood is converted to heartwood. This process alters the overall {Delta}{sup 14}C values of these transitional growth rings as cellulose with a higher {Delta}{sup 14}C content is translocated into growth rings with a relatively lower {Delta}{sup 14}C content. Once the annual nature of these growth rings is established, further stable isotope analyses on H. courbaril material in other studies may help to complete gaps in the understanding of short and of long term global climate patterns.

Westbrook, J A; Guilderson, T P; Colinvaux, P A

2004-02-09T23:59:59.000Z

226

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-Verdín, Carlos

227

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

228

A Wide Band Horizontal Accelerometer with Preliminary Earth Normal Mode and Seismic Investigations  

Science Journals Connector (OSTI)

......In considering the thermal insulation, an analogy with RC lowpass...the effectivenessof thermal insulation. In the quartz fibre accelerometer...contained in a circular layer of foam rubber on the vault floor...arecoiledinsidethe thermal insulation can. In addition, lightweight......

Jay Dratler; Barry Block

1972-05-01T23:59:59.000Z

229

A Wide Band Horizontal Accelerometer with Preliminary Earth Normal Mode and Seismic Investigations  

Science Journals Connector (OSTI)

......cable and 30AWG ribbon cable), coiled in the thermal...soft vacuum can and the cables leading out of the vault...Since these legs are not insulated, the final stage of...in a circular layer of foam rubber on the vault floor...through the electrical cables to the mechanical system......

Jay Dratler; Barry Block

1972-05-01T23:59:59.000Z

230

Fact #609: February 8, 2010 The Transportation Petroleum Gap...  

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

09: February 8, 2010 The Transportation Petroleum Gap Fact 609: February 8, 2010 The Transportation Petroleum Gap In 1989 the transportation sector petroleum consumption surpassed...

231

Fact #560: March 2, 2009 The Transportation Petroleum Gap | Department...  

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

0: March 2, 2009 The Transportation Petroleum Gap Fact 560: March 2, 2009 The Transportation Petroleum Gap In 1989 the transportation sector petroleum consumption surpassed U.S....

232

Fact #687: August 8, 2011 The Transportation Petroleum Gap |...  

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

7: August 8, 2011 The Transportation Petroleum Gap Fact 687: August 8, 2011 The Transportation Petroleum Gap In 1989 the transportation sector petroleum consumption surpassed U.S....

233

Technical Standards, MELCOR - Gap Analysis - May 3, 2004 | Department...  

Energy Savers [EERE]

3, 2004 Technical Standards, MELCOR - Gap Analysis - May 3, 2004 May 3, 2004 Software Quality Assurance Improvement Plan: MELCOR Gap Analysis This report documents the outcome of...

234

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...

235

World Wide Web Information Servers  

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

World Wide Web Information Servers World Wide Web Information Servers Lawrence Berkeley Laboratory recently announced a gopher and World Wide Web site. To get to the web site, telnet to www.lbl.gov, login: www. Access is provided to LBL's gopher, library catalog, and publication list. The Center is funding the implementation of a WWW network node for on-line access to publications, databases, and documents full of hypermedia links to other documents or information systems from the Energy & Environment Division. Full implementation is expected by May 1994, and will include access to a variety of information from all the research programs and centers. The technology transfer project calls for this newsletter to be published on WWW using the Mosaic interface under development at the National Center

236

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

237

The 6/94 gap in health impact assessment  

SciTech Connect (OSTI)

Health impact assessment (HIA), a methodology that aims to facilitate the mitigation of negative and enhancement of positive health effects due to projects, programmes and policies, has been developed over the past 20-30 years. There is an underlying assumption that HIA has become a full fledged critical piece of the impact assessment process with a stature equal to both environmental and social impact assessments. This assumption needs to be supported by evidence however. Within the context of projects in developing country settings, HIA is simply a slogan without a clearly articulated and relevant methodology, offered by academia and having little or no salience in the decision-making process regarding impacts. This harsh assertion is supported by posing a simple question: 'Where in the world have HIAs been carried out?' To answer this question, we systematically searched the peer-reviewed literature and online HIA-specific databases. We identified 237 HIA-related publications, but only 6% of these publications had a focus on the developing world. What emerges is, therefore, a huge disparity, which we coin the 6/94 gap in HIA, even worse than the widely known 10/90 gap in health research (10% of health research funding is utilized for diseases causing 90% of the global burden of disease). Implications of this 6/94 gap in HIA are discussed with pointed emphasis on extractive industries (oil/gas and mining) and water resources development. We conclude that there is a pressing need to institutionalize HIA in the developing world, as a consequence of current predictions of major extractive industry and water resources development, with China's investments in these sectors across Africa being particularly salient.

Erlanger, Tobias E. [Department of Public Health and Epidemiology, Swiss Tropical Institute, CH-4002 Basel (Switzerland)], E-mail: tobias.erlanger@unibas.ch; Krieger, Gary R. [NewFields, LLC, Denver, CO 80202 (United States)], E-mail: gkrieger@newfields.com; Singer, Burton H. [Office of Population Research, Princeton University, Princeton, NJ 08544 (United States)], E-mail: singer@princeton.edu; Utzinger, Juerg [Department of Public Health and Epidemiology, Swiss Tropical Institute, CH-4002 Basel (Switzerland)], E-mail: juerg.utzinger@unibas.ch

2008-05-15T23:59:59.000Z

238

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

239

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

240

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

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

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

242

Bridging The Gap 2013 | ornl.gov  

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

3 3 Mar 05 2013 03-05-2013 12:00 AM - 03-06-2013 05:00 PM Oak Ridge National Laboratory hosted the third annual Bridging the Gap on March 5-6, 2013. This event brought entrepreneurs, scientists, and technology transfer experts together to explore opportunities around the lab's most promising new technologies. Oak Ridge, TN CONTACT : Email: Cassie Lopez Phone:(865) 576-9294 Add to Calendar SHARE Bridging The Gap 2013 March 5-6, 2013 (Oak Ridge, TN) Tennessee A-B-C Conference Rooms (Building 5200) Oak Ridge National Laboratory hosted the third annual Bridging the Gap on March 5-6, 2013. This event brought entrepreneurs, scientists, and technology transfer experts together to explore opportunities around the lab's most promising new technologies. Keynote Address: Innovations at ORNL, Thom Mason

243

Olene Gap Geothermal Project | Open Energy Information  

Open Energy Info (EERE)

Olene Gap Geothermal Project Olene Gap Geothermal Project Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Development Project: Olene Gap Geothermal Project Project Location Information Coordinates 42.1725°, -121.62083333333° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":42.1725,"lon":-121.62083333333,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

244

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.

245

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

246

Electronic band structure of LiInSe2: A first-principles study using the Tran-Blaha density functional and GW approximation  

Science Journals Connector (OSTI)

Abstract Using first-principles theoretical techniques within density functional theory and many-body perturbation theory we investigated the structural and electronic properties of two LiInSe2 crystal modifications, orthorhombic (?-NaFeO2-type) and tetragonal (CuFeS2-type), focusing on the interband transitions and band gaps. It is found that the Tran-Blaha (TB09) functional predicts LiInSe2 to be a direct-gap semiconductor with a significantly larger band gap as compared with that from common local-density and gradient-corrected functionals. The most accurate values of the fundamental energy gaps are calculated within quasiparticle GW approximation and found to be 2.95 eV for the orthorhombic phase and 2.85 eV for the tetragonal one, with equal pressure coefficients of 63 meV/GPa. Our theoretical results eliminate the uncertainty in the band gap of LiInSe2. Moreover, the data obtained define the upper limit of the band gap of solid solutions (Cu,Li)InSe2 and (Ag,Li)InSe2, which can be of interest for applications in optoelectronics.

A.V. Kosobutsky; Yu.M. Basalaev

2014-01-01T23:59:59.000Z

247

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

248

Closing Gaps in Modeling Multifamily Retrofits  

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

Building America Technical Update Meeting Denver, Colorado April 30, 2013 Jordan Dentz, The Levy Partnership., Inc. Closing Gaps in Modeling Multifamily Retrofits Advanced Residential Integrated Energy Solutions Overview * Multifamily modeling inputs (BA House Simulation Protocols) * Important multifamily measures * Other MF gaps Vital to meet 50% goals and therefore important to include in Building America's multifamily modeling capabilities Model Inputs * Heating set point * Cooling set point * Behavior assumptions 3 Heating Set Point - Central Systems * House simulation protocol assumes 71°F * Overheating is common * Approach: adjust modeled heating set point - how much? * Average heating season indoor temperature was 76°F in a sample of 18 buildings (ARIES 2013a)

249

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

250

Alternative approaches of SiC & related wide bandgap materials in light emitting & solar cell applications  

Science Journals Connector (OSTI)

Materials for optoelectronics give a fascinating variety of issues to consider. Increasingly important are white light emitting diode (LED) and solar cell materials. Profound energy savings can be done by addressing new materials. White light emitting diodes are becoming common in our lighting scene. There is a great energy saving in the transition from the light bulb to white light emitting diodes via a transition of fluorescent light tubes. However, the white LEDs still suffer from a variety of challenges in order to be in our daily use. Therefore there is a great interest in alternative lighting solutions that could be part of our daily life. All materials create challenges in fabrication. Defects reduce the efficiency of optical transitions involved in the light emitting diode materials. The donor-acceptor co-doped SiC is a potential light converter for a novel monolithic all-semiconductor white LED. In spite of considerable research, the internal quantum efficiency is far less than theoretically predicted and is likely a fascinating scientific field for studying materials growth, defects and optical transitions. Still, efficient Si-based light source represents an ongoing research field in photonics that requires high efficiency at room temperature, wavelength tuning in a wide wavelength range, and easy integration in silicon photonic devices. In some of these devices, rare earth doped materials is considered as a potential way to provide luminescence spanning in a wide wavelength range. Divalent and trivalent oxidation states of Eu provide emitting centers in the visible region. In consideration, the use of Eu in photonics requires Eu doped thin films that are compatible with CMOS technology but for example faces material science issues like a low Eu solid solubility in silica. Therefore approaches aim to obtain efficient light emission from silicon oxycarbide which has a luminescence in the visible range and can be a host material for rare earth ions. The silicon oxycarbide material can provide potential applications of the Eu luminescent materials to challenging conditions like high temperatures or aggressive environments where the silica has weaknesses. In some approaches, silicon rich silicon oxide that contain silicon nanoclusters emit red to near infrared luminescence due to quantum confinement effects while luminescence at shorter wavelength is difficult due to the interplay of defects and quantum confinement effects. In addition it is applicable as low-k dielectric, etch-stop and passivation layers. It also has an optical band-gap that is smaller than that of SiO2 which may facilitate carrier injection at lower voltages that is suitable for optoelectronics. From materials perspective of emerging materials, it seems distant to consider system related issues. The future demands on communication and lighting devices require higher information flows in modernized optical devices, for example by replacing electrical interconnects with their optical counterparts and tunable backgrounds filters for integrated optics or photonics applications. However, there are materials issues related to such device performance, for example by a non-linearity, that provide the possibility for selective removal or addition of wavelengths using hetero structures in which one side of the structure enhances the light-to-dark sensitivity of long and medium wavelength channels and diminish others, and an opposite behavior in other face of the structure. Certainly materials may be applied in various innovative ways to provide new performances in devices and systems. In any materials and device evaluation, reliability issues in passivation and packaging of semiconductor device structures provide a base knowledge that may be used to evaluate new concepts. Fundamental aspects of dielectric constant, bandgap and band offsets between the valence and conduction band edges between the passivation layer and the semiconductor create a foundation for understanding the device performance. In relation to these, the surface pre-treatment and deposit

Peter Wellmann; Mikael Syv?j?rvi; Haiyan Ou

2014-01-01T23:59:59.000Z

251

Theoretical analysis on effect of band offsets in perovskite solar cells  

Science Journals Connector (OSTI)

Abstract The effect of band offsets in CH3NH3PbI3-xClx perovskite-based solar cells with planar junction configuration was analyzed using one-dimensional device simulator. As widely known in thin-film compound solar cells, the band offset between buffer/absorber layers is a decisive factor for carrier recombination at the interface, determining open-circuit voltage (Voc). In this study, the impact of two kinds of band offsets, i.e., the conduction band offset of buffer (or blocking layer)/absorber layers and the valence band offset of absorber/hole transport material (HTM) were examined. When the conduction band of the buffer was lower than that of the absorber, the interface recombination became prominent and Voc decreased. In contrast, when the conduction band of the buffer was higher than that of the absorber by more than 0.3 eV, the collection of photo-generated carriers, i.e. electron in this case, was impeded by the spike formed by the conduction band offset. Thus, the optimum position of the conduction band of the buffer was 0.0~0.3 eV higher than that of the absorber. Also, the optimum position of the valence band of the HTM was derived to be 0.0~0.2 eV lower than that of the absorber. These findings will be useful for new material choice and optimization of buffers and HTMs.

Takashi Minemoto; Masashi Murata

2015-01-01T23:59:59.000Z

252

Local indium segregation and band structure in high efficiencygreen light emitting InGaN/GaN diodes  

SciTech Connect (OSTI)

GaN/InGaN light emitting diodes (LEDs) are commercialized for lighting applications because of the cost efficient way that they produce light of high brightness. Nevertheless, there is significant room for improving their external emission efficiency from typical values below 10 percent to more than 50 percent, which are obtainable by use of other materials systems that, however, do not cover the visible spectrum. In particular, green-light emitting diodes fall short in this respect, which is troublesome since the human eye is most sensitive in this spectral range. In this letter advanced electron microscopy is used to characterize indium segregation in InGaN quantum wells of high-brightness, green LEDs (with external quantum efficiency as high as 15 percent at 75 A/cm2). Our investigations reveal the presence of 1-3 nm wide indium rich clusters in these devices with indium concentrations as large as 0.30-0.40 that narrow the band gap locally to energies as small as 2.65 eV.

Jinschek, Joerg R.; Erni, Rolf; Gardner, Nathan F.; Kim, AndrewY.; Kisielowski, Christian

2004-11-23T23:59:59.000Z

253

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

254

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

255

Improved gap size estimation for scaffolding algorithms  

Science Journals Connector (OSTI)

......and 950 bp. The contigs were set to a fixed size of 3000 bp...three read libraries and four sets of contigs). The results of...parts of the distribution fail to cover the gap and only the longest...we simulated four different sets of contigs from the genome with......

Kristoffer Sahlin; Nathaniel Street; Joakim Lundeberg; Lars Arvestad

2012-09-01T23:59:59.000Z

256

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

257

Spark gap device for precise switching  

DOE Patents [OSTI]

A spark gap device for precise switching of an energy storage capacitor into an exploding bridge wire load is disclosed. Niobium electrodes having a melting point of 2,415 degrees centrigrade are spaced apart by an insulating cylinder to define a spark gap. The electrodes are supported by conductive end caps which, together with the insulating cylinder, form a hermetically sealed chamber filled with an inert, ionizable gas, such as pure xenon. A quantity of solid radioactive carbon-14 within the chamber adjacent the spark gap serves as a radiation stabilizer. The sides of the electrodes and the inner wall of the insulating cylinder are spaced apart a sufficient distance to prevent unwanted breakdown initiation. A conductive sleeve may envelop the outside of the insulating member from the midpoint of the spark gap to the cap adjacent the cathode. The outer metallic surfaces of the device may be coated with a hydrogen-impermeable coating to lengthen the shelf life and operating life of the device. The device breaks down at about 1,700 volts for input voltage rates up to 570 volts/millisecond and allows peak discharge currents of up to 3,000 amperes from a 0.3 microfarad energy storage capacitor for more than 1,000 operations.

Boettcher, Gordon E. (Albuquerque, NM)

1984-01-01T23:59:59.000Z

258

Spark gap device for precise switching  

DOE Patents [OSTI]

A spark gap device for precise switching of an energy storage capacitor into an exploding bridge wire load is disclosed. Niobium electrodes having a melting point of 2,415 degrees centigrade are spaced apart by an insulating cylinder to define a spark gap. The electrodes are supported by conductive end caps which, together with the insulating cylinder, form a hermetically sealed chamber filled with an inert, ionizable gas, such as pure xenon. A quantity of solid radioactive carbon-14 within the chamber adjacent the spark gap serves as a radiation stabilizer. The sides of the electrodes and the inner wall of the insulating cylinder are spaced apart a sufficient distance to prevent unwanted breakdown initiation. A conductive sleeve may envelop the outside of the insulating member from the midpoint of the spark gap to the cap adjacent the cathode. The outer metallic surfaces of the device may be coated with a hydrogen-impermeable coating to lengthen the shelf life and operating life of the device. The device breaks down at about 1,700 volts for input voltage rates up to 570 volts/millisecond and allows peak discharge currents of up to 3,000 amperes from a 0.3 microfarad energy storage capacitor for more than 1,000 operations. 3 figs.

Boettcher, G.E.

1984-10-02T23:59:59.000Z

259

Gap states in Pentacene Thin Film Induced by Inert Gas Exposure  

Science Journals Connector (OSTI)

We studied gas-exposure effects on pentacene (Pn) films on SiO2 and Au(111) substrates by ultrahigh sensitivity photoelectron spectroscopy, which can detect the density of states of ?1016 states eV-1?cm-3 comparable to electrical measurements. The results show the striking effects for Pn/SiO2: exposure to inert gas (N2 and Ar) produces a sharp rise in gap states from ?1016 to ?1018 states eV-1?cm-3 and pushes the Fermi level closer to the valence band (0.15–0.17 eV), as does exposure to O2 (0.20 eV), while no such gas-exposure effect is observed for Pn/Au(111). The results demonstrate that these gap states originate from small imperfections in the Pn packing structure, which are induced by gas penetration into the film through the crystal grain boundaries.

Fabio Bussolotti; Satoshi Kera; Kazuhiro Kudo; Antoine Kahn; Nobuo Ueno

2013-06-25T23:59:59.000Z

260

BNL | S-band Linac  

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

S-band Linac S-band Linac Some experiments at the ATF require higher energies than what is available from the photoinjector. We use two traveling wave linac structures, known as 'SLAC sections' (from the famous 2-mile SLAC linac). Each section provides an acceleration given by: Energy gain (in MeV) = 10.8*SQRT(Power in MW)-39.5*Current(in amps) The current to be used is an equivalent steady state current. The microwave drive power, at a frequency of 2856 MHz, is provided by a single XK5 klystron tube (the old SLAC klystron). This tube can provide up to 25 MW. The ATF modulator can provide the XK5 klystron with high voltage for about 3 microseconds. This 3 microsecond pulse is called the macropulse. The repetition rate for the macropulses is from 1 to 6 per second. Within each

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261

Hanford Site Wide Programs - Hanford Site  

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

Decrease Font Size Hanford Site Wide Programs Hanford Safety Hanford Site Wide Programs Hanford Fire Department Health & Safety Exposition Hanford Traffic Safety Hanford...

262

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...

263

Analysis of the interband optical transitions: Characterization of synthetic DNA band structure  

Science Journals Connector (OSTI)

We analyze the band structure and interband optical transitions in a dangling backbone ladder DNAmodel. Using this model semiconducting synthetic poly(G)-poly(C) DNA is studied by means of a tight-binding model traditionally used for transport studies. Numerical calculations for optical absorptionspectra are also presented. By studying the eigenstates’ symmetries in uniform and nonuniform DNA chains we conclude that in both cases the transitions are almost vertical in K space. The optical gap turns out larger than the electronic one and an indirect band gap electronic structure for this DNAmodel is revealed. The effects of the environment which are relevant for the wet form of DNA are taken into account by introducing disorder in the backbone levels. We demonstrate that they affect more the spectra in the case of parallel polarization of the incoming light (with respect to the molecule axis). In such a case the closure of the gap appears for a large enough disorder. We also consider the natural helix DNA conformation and find unusual selection rules for interband optical transitions. We propose that a comparison between the obtained spectra and the experiments can provide an insight into the electronic band structure of DNA.

Elena Díaz

2008-01-01T23:59:59.000Z

264

Luminescence studies of localized gap states in colloidal ZnS nanocrystals D. Denzler, M. Olschewski, and K. Sattlera)  

E-Print Network [OSTI]

form are the II-VI semi- conductor compounds CdS and ZnS.14 ZnS has a band gap of 3.6 eV at 300 K spectra show a broad ultraviolet peak at around 420 nm. ZnS can be doped with Mn very easily, where few Mn atoms substitute for Zn atoms.18 This doping causes a visible orange luminescence at about 590 nm. Both

Sattler, Klaus

265

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

266

Bridging the Gap 2011 | ornl.gov  

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

1 1 Apr 05 2011 04-05-2011 08:00 AM - 04-06-2011 05:00 PM Oak Ridge National Laboratory's Partnerships Directorate will host Bridging the Gap, a unique technology commercialization event, April 5-6 at Oak Ridge National Laboratory. Oak Ridge, TN Oak Ridge National Laboratory CONTACT : Email: Cassie Lopez Phone:(865) 576-9294 Add to Calendar SHARE Oak Ridge National Laboratory's Partnerships Directorate will host Bridging the Gap, a unique technology commercialization event, April 5-6 at Oak Ridge National Laboratory. The event will provide investors and entrepreneurs opportunities to learn about promising ORNL technologies available for license and to hear from ORNL licensees seeking growth capital. There will also be opportunities to tour ORNL's world-class research facilities and network with some of the

267

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

268

Vibration-Rotation Bands of Trideuteromethyl Iodide  

Science Journals Connector (OSTI)

5 October 1965 research-article Vibration-Rotation Bands of Trideuteromethyl...of six parallel and nine perpendicular vibration bands of trideuteromethyl iodide has...constants for the fundamental degenerate vibrations. The values for overtone and combination...

1965-01-01T23:59:59.000Z

269

Bridging the Gap: Linking Simulation and Testing  

SciTech Connect (OSTI)

The Materials Genome Initiative (MGI) which is a key enabler for the Advanced Manufacturing Partnership, announced in 2011 by U.S. President Barack Obama, was established to accelerate the development and deployment of advanced materials. The MGI is driven by the need to "bridge the gap" between (I) experimental results and computational analysis to enable the rapid development and validation of new mateirals, and (II) the processes required to convert these materials into useable goods.

Krajewski, Paul E.; Carsley, John; Stoudt, Mark R.; Hovanski, Yuri

2012-09-01T23:59:59.000Z

270

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

271

NSLS prototype small-gap undulator (PSGU)  

SciTech Connect (OSTI)

The NSLS Prototype Small-Gap Undulator (PSGU) will serve as a tool to study lifetime degradation and the onset of beam instabilities as the beam duct aperture is decreased. The device will consist of variable-gap vacuum vessel had a permanent magnet undulator, with independent magnet-gap control. The vacuum vessel design attempts to minimize both residual gas pressures and beam impedances. The undulator will be 320 mm long and utilizes a pure-permanent-magnet structure with 6 blocks per 16 mm period. For a nominal operating aperture of 4 mm, PSGU will produce a peak brightness in the fundamental and third harmonic of 7 {times} 10{sup 16} and 1 {times} 10{sup 16} photons{sm bullet}sec{sup {minus}1}{sm bullet}mrad{sup {minus}2}mm{sup {minus}2}{sm bullet}(0.1% BW){sup {minus}1} at photon energies of 2.5 keV and 7.5 keV, respectively. 5 refs., 3 figs., 2 tabs.

Stefan, P.M.; Solomon, L.; Krinsky, S. (Brookhaven National Lab., Upton, NY (United States)); Rakowsky, G. (Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.)

1991-01-01T23:59:59.000Z

272

Superdeformed bands in sup 194 Tl  

SciTech Connect (OSTI)

Superdeformation was first observed in the mass-190 region in {sup 191}Hg. Since then, SD bands have been found in {sup 190-194}Hg nuclei. Here we report the discovery of two such bands in {sup 194}Tl which are the first SD bands fond in this mass region that are not in Hg nuclei. Subsequently, bands have been found in two Pb nuclei. 5 refs., 1 fig.

Azaiez, F.; Kelly, W.H.; Korten, W.; Deleplanque, M.A.; Stephens, F.S.; Diamond, R.M.; Beausang, C.W.; Draper, J.E.; Rubel, E. (Lawrence Berkeley Lab., CA (USA)); Becker, J.A.; Henry, E.A.; Brinkman, M.J.; Yates, S.W.; Kuhnert, A. (Lawrence Livermore National Lab., CA (USA))

1990-05-01T23:59:59.000Z

273

Scaling of distributions of sums of positions for chaotic dynamics at band-splitting points  

E-Print Network [OSTI]

The stationary distributions of sums of positions of trajectories generated by the logistic map have been found to follow a basic renormalization group (RG) structure: a nontrivial fixed-point multi-scale distribution at the period-doubling onset of chaos and a Gaussian trivial fixed-point distribution for all chaotic attractors. Here we describe in detail the crossover distributions that can be generated at chaotic band-splitting points that mediate between the aforementioned fixed-point distributions. Self affinity in the chaotic region imprints scaling features to the crossover distributions along the sequence of band splitting points. The trajectories that give rise to these distributions are governed first by the sequential formation of phase-space gaps when, initially uniformly-distributed, sets of trajectories evolve towards the chaotic band attractors. Subsequently, the summation of positions of trajectories already within the chaotic bands closes those gaps. The possible shapes of the resultant distributions depend crucially on the disposal of sets of early positions in the sums and the stoppage of the number of terms retained in them.

Alvaro Diaz-Ruelas; Miguel Angel Fuentes; Alberto Robledo

2014-09-26T23:59:59.000Z

274

UT-TRIBE-NORTHWESTERN BAND OF SHOSHONE  

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

U.S. Department of Energy Categorical Exclusion Determination Form Program or Field Office: Energy Efficiency and Conservation Block Grant Program Project Title UT-TRIBE-NORTHWESTERN BAND OF SHOSHONE Location: Tribe UT-TRIBE- NORTHWESTERN BAND OF SHOSHONE UT American Recovery and Reinvestment Act: Proposed Action or Project Description The Northwestern Band of Shoshone Nation of Utah proposes to perform energy efficiency improvements

275

Technical Standards, GENII- Gap Analsis - May 3, 2004 | Department of  

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

Technical Standards, GENII- Gap Analsis - May 3, 2004 Technical Standards, GENII- Gap Analsis - May 3, 2004 Technical Standards, GENII- Gap Analsis - May 3, 2004 May 3, 2004 Software Quality Assurance Improvement Plan: GENII Gap Analysis The GENII software, for radiological dispersion and consequence analysis, is one of the codes designated for the toolbox. To determine the actions needed to bring the GENII code into compliance with the SQA qualification criteria, and develop an estimate of the resources required to perform the upgrade, the Implementation Plan has committed to sponsoring a code-specific gap analysis document. Technical Standards, GENII- Gap Analsis More Documents & Publications Guidance on GENII computer code - July 6, 2004 Technical Standards, ALOHA-Gap Analysis - May 3, 2004 Technical Standards, MELCOR - Gap Analysis - May 3

276

Fact #610: February 15, 2010 All Sectors' Petroleum Gap | Department...  

Energy Savers [EERE]

10: February 15, 2010 All Sectors' Petroleum Gap Fact 610: February 15, 2010 All Sectors' Petroleum Gap Before 1989 the U.S. produced enough petroleum to meet the needs of the...

277

Fact #688: August 15, 2011 All Sectors' Petroleum Gap | Department...  

Energy Savers [EERE]

8: August 15, 2011 All Sectors' Petroleum Gap Fact 688: August 15, 2011 All Sectors' Petroleum Gap Before 1989 the U.S. produced enough petroleum to meet the needs of the...

278

Technical Standards, MACCS2, Gap Analysis - May 3, 2004 | Department...  

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

3, 2004 Technical Standards, MACCS2, Gap Analysis - May 3, 2004 May 3, 2004 Software Quality Assurance Improvement Plan: MACCS2 Gap Analysis The MACCS2 software, for radiological...

279

Functional Area Qualification Standard Gap Analysis Qualification Cards  

Broader source: Energy.gov [DOE]

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

280

Intelligent Assistants for Filling Critical Gaps in GIS  

E-Print Network [OSTI]

Intelligent Assistants for Filling Critical Gaps in GIS A Research Program April 1992 David Lanter, Intelligent Assistants for Filling Critical Gaps In GIS, was sponsored by Southern California Edison Company: · An analysis of critical gaps in current geographic information systems (GIS) that impede their use for spatial

California at Santa Barbara, 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.


281

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

282

Metallic-nanoparticle assisted enhanced band-to-band tunneling current Deblina Sarkara)  

E-Print Network [OSTI]

Metallic-nanoparticle assisted enhanced band-to-band tunneling current Deblina Sarkara) and Kaustav) Metallic nanoparticle assisted band-to-band tunneling is proposed, and the impact of such nanoparticle that an asymmetric pinning is required to leverage maximum benefits from the insertion of metallic nanoparticles. VC

283

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

284

The semantic gap of formalized meaning  

Science Journals Connector (OSTI)

Recent work in Ontology learning and Text mining has mainly focused on engineering methods to solve practical problem. In this thesis, we investigate methods that can substantially improve a wide range of existing approaches by minimizing the underlying ...

Sebastian Hellmann

2010-05-01T23:59:59.000Z

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  

SciTech Connect (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, Loïc

2010-01-01T23:59:59.000Z

288

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

289

Wide Bandgap Semiconductors: Pursuing the Promise  

Broader source: Energy.gov [DOE]

Wide bandgap semiconductor materials are more efficient than their silicon-based counterparts; making it possible to reduce weight, volume, and life-cycle costs in a wide range of power applications.

290

Thermodynamics of MgB2 described by the weak-coupling two-band BCS model  

E-Print Network [OSTI]

.6 for the ratio of the gaps at two conductivity bands. On the other hand, the measured gaps are the same for the tunneling in the ab-plane and in the c-direction, indicating that they do not depend on direction within each piece of the Fermi surface... Integration in Eq. s2d proceeds over the Fermi surface with ds=dS /8p3 with dS being a differential area of the Fermi surface; nF=eds /vF is the electron density of the state per spin at Fermi level. The function xskd is normalized as fol- lows: kx2skdl...

Mishonov, TM; Pokrovsky, Valery L.; Wei, HD.

2005-01-01T23:59:59.000Z

291

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

292

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

293

Band offsets from two special GaAs-AlxGa1-xAs quantum-well structures  

Science Journals Connector (OSTI)

Half-parabolic quantum wells and two-stepped quantum wells have been grown by molecular-beam epitaxy with the GaAs-AlxGa1-xAs system and investigated by photoluminescence techniques to determine the band offsets at the heterointerfaces. Both structures provide interband transitions that are sensitive to the partitioning of the energy-gap discontinuity ?Eg=?Ec+?Ev between the conduction and valence bands. It is concluded that the data require valence-band offsets ?Ev equal to 38% and 41% of ?Eg for the half-parabolic wells and the two-stepped wells, respectively. These band offsets are therefore in agreement with the trend of other recent determinations.

R. C. Miller; A. C. Gossard; D. A. Kleinman

1985-10-15T23:59:59.000Z

294

Nuclear Band Structure in Sc41  

Science Journals Connector (OSTI)

Band structure predictions assuming the formation of proton single-particle states above the Ca40 core in the ground state or one of its excited states are compared with the available data on the elastic and inelastic scattering of protons from Ca40. The band expected above the 3.35-Mev state in Ca40 is confirmed by experimental results, and some evidence is found for bands above the higher core states.

R. H. Davis

1959-09-15T23:59:59.000Z

295

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

296

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

297

Investigations into Cost Reductions of X-band Instrumentation  

SciTech Connect (OSTI)

The prohibitive costs of commercial test equipment for making fast and accurate pulsed phase and amplitude measurements at X-Band result in decreased productivity due to shortages of shared equipment across the test laboratory. In addition, most current set-ups rely on the use of pulsed power heads which do not allow for the measurement of phase thereby limiting the flexibility of available measurements. In this paper, we investigate less expensive in-house designed instrumentation based upon commercial satellite down converters and widely available logarithmic detector amplifiers and phase detectors. The techniques are used to measure X-Band pulses with widths of 50 ns to 10's of usec. We expect a dynamic range of 30-40 dB with accuracies of better than +/- 0.1 dB and +/- 1 degree of phase. We show preliminary results of the built and tested modules. Block diagrams of the down conversion scheme, and the architecture of a multi-signal X-band RF monitor and measurement system is illustrated. Measured results, and possible modifications and upgrades are presented.

Van Winkle, D.; Dolgashev, V.A.; Fox, J.D.; Tantawi, S.G.; /SLAC

2009-05-15T23:59:59.000Z

298

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

299

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

300

Band offsets of ultrathin high-{kappa} oxide films with Si  

SciTech Connect (OSTI)

Valence- and conduction-band edges of ultrathin oxides (SiO{sub 2}, HfO{sub 2}, Hf{sub 0.7}Si{sub 0.3}O{sub 2}, ZrO{sub 2}, and Al{sub 2}O{sub 3}) grown on a silicon substrate have been measured using ultraviolet photoemission and inverse photoemission spectroscopies in the same UHV chamber. The combination of these two techniques has enabled the direct determination of the oxide energy gaps as well as the offsets of the oxide valence- and conduction-band edges from those of the silicon substrate. These results are supplemented with synchrotron x-ray photoemission spectroscopy measurements allowing further characterization of the oxide composition and the evaluation of the silicon substrate contribution to the spectra. The electron affinity has also been systematically measured on the same samples. We find reasonably good agreement with earlier experiments where assumptions regarding energy-gap values were needed to establish the conduction-band offsets. The systematics of our photoemission and inverse photoemission results on different ultrathin films provide a comprehensive comparison of these related systems.

Bersch, Eric; Rangan, Sylvie; Bartynski, Robert Allen; Garfunkel, Eric; Vescovo, Elio [Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, 136 Frelinghuysen Road, Piscataway, New Jersey 08854 (United States); Department of Chemistry and Chemical Biology and Laboratory for Surface Modification, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854 (United States); National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States)

2008-08-15T23:59:59.000Z

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.


301

Structural organization of gap junction channels  

Science Journals Connector (OSTI)

Gap junctions were initially described morphologically, and identified as semi-crystalline arrays of channels linking two cells. This suggested that they may represent an amenable target for electron and X-ray crystallographic studies in much the same way that bacteriorhodopsin has. Over 30 years later, however, an atomic resolution structural solution of these unique intercellular pores is still lacking due to many challenges faced in obtaining high expression levels and purification of these structures. A variety of microscopic techniques, as well as NMR structure determination of fragments of the protein, have now provided clearer and correlated views of how these structures are assembled and function as intercellular conduits. As a complement to these structural approaches, a variety of mutagenic studies linking structure and function have now allowed molecular details to be superimposed on these lower resolution structures, so that a clearer image of pore architecture and its modes of regulation are beginning to emerge.

Gina E. Sosinsky; Bruce J. Nicholson

2005-01-01T23:59:59.000Z

302

K=0 Rotational Bands in Yb174  

Science Journals Connector (OSTI)

The ? deexcitation of three excited K=0 rotational bands has been studied following population in the Yb173(n,?) reaction at resonant neutron energies of 4.53 and 17.7 eV. The ? rays were detected in singles and coincidence with Ge(Li) detectors. Analysis was also made of the primary radiation. The decay properties of these bands exhibit strong deviations from the Alaga ratios. For the lowest excited K=0 band the deexcitation branching ratios resemble those in the even-even Sm, Gd, Yb, and W nuclei. The higher-lying K=0 bands in Yb174 decay similarly to those in Yb172 but considerably differently from the lowest K=0 bands in this region. The pairing-vibrational character of the K=0 bands in Yb174, as shown by (p,t) and (t,p) reaction studies, apparently does not greatly alter the relative decay rates for these states. Two-band mixing of each K=0 band with the ground band cannot explain all the observed results, nor can three-band mixing involving the ? vibration. The presence of M1 components in the I?I transitions could explain some of the anomalous branching ratios but cannot be a complete explanation. It is suggested that multiband mixing including the excited K=0 bands themselves may have to be considered. The two-neutron-transfer-reaction data can also be interpreted in terms of such mixing. The observed similarities between Yb174 and other nuclei in this region suggest a corresponding similarity of mixing effects.

R. F. Casten; D. Breitig; W. R. Kane; S. F. Mughabghab

1973-09-01T23:59:59.000Z

303

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

304

Software Quality Assurance Improvment Plan: CFAST Gap Analysis, Final Report  

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

EH-4.2.1.3-CFAST-Gap Analysis EH-4.2.1.3-CFAST-Gap Analysis Defense Nuclear Facilities Safety Board Recommendation 2002-1 Software Quality Assurance Improvement Plan Commitment 4.2.1.3: Software Quality Assurance Improvement Plan: CFAST Gap Analysis Final Report U.S. Department of Energy Office of Environment, Safety and Health 1000 Independence Ave., S.W. Washington, DC 20585-2040 May 2004 CFAST Gap Analysis May 2004 Final Report ii INTENTIONALLY BLANK CFAST Gap Analysis May 2004 Final Report iii FOREWORD This report documents the outcome of an evaluation of the Software Quality Assurance (SQA) attributes of the CFAST computer code for accident analysis applications, relative to established requirements. This evaluation, a "gap analysis," is performed to meet commitment 4.2.1.3 of the Department of Energy's

305

Technical Standards, MELCOR - Gap Analysis - May 3, 2004 | Department of  

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

MELCOR - Gap Analysis - May 3, 2004 MELCOR - Gap Analysis - May 3, 2004 Technical Standards, MELCOR - Gap Analysis - May 3, 2004 May 3, 2004 Software Quality Assurance Improvement Plan: MELCOR Gap Analysis This report documents the outcome of an evaluation of the Software Quality Assurance (SQA) attributes of the MELCOR computer code for leak path factor applications, relative to established software requirements. This evaluation, a "gap analysis," is performed to meet Commitment 4.2.1.3 of the Department of Energy's Implementation Plan to resolve SQA issues identified in the Defense Nuclear Facilities Safety Board Recommendation 2002-1. Technical Standards, MELCOR - Gap Analysis More Documents & Publications Technical Standards, Guidance on MELCOR computer code - May 3, 2004

306

The Band Spectra of SbF and BiF  

Science Journals Connector (OSTI)

New band spectra attributed to the molecules SbF and BiF have been excited by active nitrogen. The spectrum of SbF from 2000-5500A is found to have three groups of bands lying in the regions 3600-5200A, 2600-2700A and 2200-2430A. Analysis of the first group shows that sixty-one bands out of sixty-nine can be placed into two systems with the following vibrational constants, in cm-1:— System?e?e?xe??e??e??xe???e??A121887.5411.31.71616.92.89A223992.5420.01.75612.62.58 The second group consists of a few isolated bands degraded to shorter wave-lengths and the third of bands in closely spaced sequences and also degraded to shorter wave-lengths. A preliminary analysis indicates that the bands in the latter group can be placed into two systems for which ?e??700 cm-1, ?e???620 cm-1 and ??21?1850 cm-1. Three new systems of bands, degraded to shorter wave-lengths and forming a triplet system with wide multiplet separations, (7330 cm-1 and 4800 cm-1), are found in the spectrum of BiF at 3050-3250A, 2650-2850A and 2250-2350A. Photographs taken with small dispersion indicate that ?e??620 cm-1 and ?e???520 cm-1.

George D. Rochester

1937-03-15T23:59:59.000Z

307

Two-gap elliptic solutions of the Boussinesq equation  

SciTech Connect (OSTI)

Two-gap solutions of the Boussinesq equation are considered. It is shown that for almost every Riemann surface {gamma} of genus g=2 covering the elliptic surface it is possible to construct an elliptic (in x) two-gap solution of the Boussinesq equation. The existence of third- and fourth-order differential operators with elliptic 'two-gap' potentials having an arbitrary number of poles is also established. An example is given.

Smirnov, A O [Saint-Petersburg State University of Aerospace Instrumentation, Saint-Petersburg (Russian Federation)

1999-06-30T23:59:59.000Z

308

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

309

Enterprise-Wide Agreements | Department of Energy  

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

Enterprise-Wide Enterprise-Wide Agreements Enterprise-Wide Agreements DOE's Office of the Chief Information Officer (OCIO) has designed the IT Acquisition: Enterprise-Wide Agreement (EWA) Program to develop and implement policies and procedures that support the identification, acquisition, oversight and compliance of enterprise licenses. EWAs are Department-wide acquisitions of widely used commercial software. The EWA Program has two core objectives to achieve the Program mission : Maximizing IT buying power and reducing total cost of ownership; Streamlining the IT total acquisition lifecycle. The EWA Program applies a centralized, cross-functional, strategic enterprise software solutions approach. The EWA Program leverages opportunities to create efficiencies and enhances the value of IT

310

Possible quasimolecular bands in /sup 32/S  

SciTech Connect (OSTI)

Below the /sup 16/O+ /sup 16/O threshold, positive- and negative-parity bands at E/sub x/ = 11--17 MeV in /sup 32/S are identified, whose moments of inertia and ..cap alpha..-reduced widths indicate possible quasimolecular bands of /sup 16/O+ /sup 16/O and of some asymmetric configuration.

Morita, K.; Kubono, S.; Tanaka, M.H.; Utsunomiya, H.; Sugitani, M.; Kato, S.; Schimizu, J.; Tachikawa, T.; Takahashi, N.

1985-07-08T23:59:59.000Z

311

Combined Heat and Power: Connecting the Gap between Markets and...  

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

Combined Heat and Power: Connecting the Gap between Markets and Utility Interconnection and Tariff Practices (Part I) Susanne Brooks, Brent Elswick, and R. Neal Elliott March 2006...

312

To Bridge LEDs' Green Gap, Scientists Think Small  

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

emitting diodes (LEDs), especially in the "green gap," a portion of the spectrum where LED efficiency plunges, simulations at the U.S. Department of Energy's National Energy...

313

FAQS Gap Analysis Qualification Card – Civil Structural 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.

314

FAQS Gap Analysis Qualification Card - Technical Training | Department...  

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

Description Technical Training Gap Analysis Qualification Card More Documents & Publications DOE-STD-1179-2004 DOE-HDBK-1078-94 FAQS Reference Guide - Technical Training...

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 – Nuclear Safety Specialist  

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

Information Gap Decision Theory based OPF with HVDC Connected ...  

E-Print Network [OSTI]

curve as well as the uncertainties of wind power generation. Information gap .... its own advantages and disadvantages, which are summarized as follows.

2014-12-01T23:59:59.000Z

318

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.

319

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.

320

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.

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

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

322

Preparation of narrow band gap V2O5/TiO2 composite films by micro-arc oxidation  

Science Journals Connector (OSTI)

V2O5/TiO2...composite films were prepared on pure titanium substrates via micro-arc oxidation (MAO) in electrolytes consisting of NaVO3. Their morphology and elements were characterized by scanning electron micro...

Qiang Luo; Xin-wei Li; Qi-zhou Cai…

2012-11-01T23:59:59.000Z

323

Experimental investigation on wave run-up characteristics along columns and air gap response of semi-submersible platform  

Science Journals Connector (OSTI)

This article mainly concentrates on a large-volume drilling semi-submersible platform, aiming to reveal wave run-up characteristics along square columns and give the relationship between air gap distributions and wave parameters. The tests with fixed model were conducted firstly on its encountering a series of monochromatic waves. A wide range of wave slope (H/L) were selected to investigate the air gap response in detail. As can be seen, larger wave steepness will generally cause smaller air gap in the same wave period, which indicates nonlinear effects of incoming wave can amplify wave elevation. Model tests with mooring condition were also conducted in the same wave conditions. As was expected, the maximum relative wave elevation reduces obviously compared with the fixed one. However, wave shape close to columns show higher harmonic characteristics due to interaction between waves and the columns of semi-submersible platform. Meaningful conclusions from the model tests are drawn in this article, which is helpful in air gap design of floating offshore platform to a certain extent. In addition, the experimental results will provide an important reference for further research on validation and update of theoretical models of air gap.

Tie-bing SHAN; Jian-min YANG; Xin LI; Long-fei XIAO

2011-01-01T23:59:59.000Z

324

Optimization towards high density quantum dots for intermediate band solar cells grown by molecular beam epitaxy  

SciTech Connect (OSTI)

We report high density quantum dots (QDs) formation with optimized growth temperature and V/III ratio. At lower growth temperature, QD density is increased, due to smaller surface migration length of In adatoms. With higher V/III, the QD density is higher but it results in large clusters formation and decreases the QD uniformity. The QD solar cell was fabricated and examined. An extended spectral response in contrast to the GaAs reference cell was presented but the external quantum efficiency at energies higher than GaAs band gap is reduced, resulting from the degradation for the emitter above the strained QD layers.

Zhou, D.; Sharma, G.; Fimland, B. O. [Department of Electronics and Telecommunications, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Thomassen, S. F.; Reenaas, T. W. [Department of Physics, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway)

2010-02-08T23:59:59.000Z

325

Rural Microfinance Service Delivery: Gaps, Inefficiencies and Emerging Solutions  

E-Print Network [OSTI]

Rural Microfinance Service Delivery: Gaps, Inefficiencies and Emerging Solutions Tapan S. Parikh emerged as one of the most promising avenues for stimulating rural economic devel- opment through local enterprise. In this paper we will discuss some of the major technology gaps faced by rural microfinance

Parikh, Tapan S.

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

Modeling of electroabsorption in semiconductor quantum structures within the eight-band k?p theory  

Science Journals Connector (OSTI)

We have incorporated electric fields into the eight-band k?p theory, which we have applied to heterostructures, in conjunction with the envelope-function approximation. We use the method of Baraff and Gershoni to implement the electric-field effects in a computer program that calculates the optical properties of direct-band-gap heterostructures in one, two, and three dimensions. Using this method, we calculate the interband and intersubband electroabsorption of multiple quantum wells as well as the interband electroabsorption in superlattices. We illustrate the evolution of the Stark localization of the electron wave function under the application of an external electric field in superlattices. Comparison with experimental data, available in the literature, exhibits very good agreement between theory and experiment, with respect to the spectral shape, the absolute magnitude, and the electric-field dependence of the absorption.

Mats-Erik Pistol and David Gershoni

1994-10-15T23:59:59.000Z

328

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

329

Review of Used Nuclear Fuel Storage and Transportation Technical Gap  

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

Analysis Analysis Review of Used Nuclear Fuel Storage and Transportation Technical Gap Analysis While both wet and dry storage have been shown to be safe options for storing used nuclear fuel (UNF), the focus of the program is on dry storage of commercial UNF at reactor or centralized locations. This report focuses on the knowledge gaps concerning extended storage identified in numerous domestic and international investigations and provides the Used Fuel Disposition Campaign"s (UFDC) gap description, any alternate gap descriptions, the rankings by the various organizations, evaluation of the priority assignment, and UFDC-recommended action based on the comparison. Review of Used Nuclear Fuel Storage and Transportation Technical Gap Analysis More Documents & Publications

330

Spectral gap and logarithmic Sobolev constant for continuous spin systems  

E-Print Network [OSTI]

The aim of this paper is to study the spectral gap and the logarithmic Sobolev constant for continuous spin systems. A simple but general result for estimating the spectral gap of finite dimensional systems is given by Theorem 1.1, in terms of the spectral gap for one-dimensional marginals. The study of the topic provides us a chance, and it is indeed another aim of the paper, to justify the power of the results obtained previously. The exact order in dimension one (Proposition 1.4), and then the precise leading order and the explicit positive regions of the spectral gap and the logarithmic Sobolev constant for two typical infinite-dimensional models are presented (Theorems 6.2 and 6.3). Since we are interested in explicit estimates, the computations become quite involved. A long section (Section 4) is devoted to the study of the spectral gap in dimension one.

Mu-Fa Chen

2010-04-26T23:59:59.000Z

331

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

332

Field-induced gap and quantized charge pumping in a nanoscale helical wire  

Science Journals Connector (OSTI)

We propose several physical phenomena based on nanoscale helical wires. Applying a static electric field transverse to the helical wire induces a metal to insulator transition, with the band gap determined by the applied voltage. A similar idea can be applied to “geometrically” construct one-dimensional systems with arbitrary external potential. With a quadrupolar electrode configuration, the electric field could rotate in the transverse plane, leading to a quantized dc charge current proportional to the frequency of the rotation. Such a device could be used as a standard for the high-precession measurement of the electric current. The inverse effect implies that passing an electric current through a helical wire in the presence of a transverse static electric field can lead to a mechanical rotation of the helix. This effect can be used to construct nanoscale electromechanical motors. Finally, our methodology also enables ways of controlling and measuring the electronic properties of helical biological molecules such as the DNA.

Xiao-Liang Qi and Shou-Cheng Zhang

2009-06-30T23:59:59.000Z

333

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

334

ARM - Campaign Instrument - s-band-profiler  

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

govInstrumentss-band-profiler govInstrumentss-band-profiler Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign Instrument : NOAA S-band (2835 Mhz) Profiler (S-BAND-PROFILER) Instrument Categories Cloud Properties, Atmospheric Profiling Campaigns CRYSTAL-FACE [ Download Data ] Off Site Campaign : various, including non-ARM sites, 2002.06.26 - 2002.08.01 Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers [ Download Data ] Southern Great Plains, 2011.04.22 - 2011.06.06 Tropical Warm Pool - International Cloud Experiment (TWP-ICE) [ Download Data ] Tropical Western Pacific, 2006.01.21 - 2006.02.13 Primary Measurements Taken The following measurements are those considered scientifically relevant. Refer to the datastream (netcdf) file headers for the list of all available

335

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

336

Precipitation Banding in Idealized Baroclinic Waves  

Science Journals Connector (OSTI)

Moist idealized baroclinic-wave simulations show the development of precipitation bands from a zonally uniform initial midlatitude jet. For a frictionless lower boundary, and with no latent-heat release or surface heat and moisture fluxes, warm ...

Jesse Norris; Geraint Vaughan; David M. Schultz

2014-09-01T23:59:59.000Z

337

Agency-Wide Screening | Department of Energy  

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

Agency-Wide Screening Agency-Wide Screening Agency-Wide Screening October 16, 2013 - 4:36pm Addthis Federal agencies face energy-related requirements on new construction projects and major renovations. These Federal requirements range from reductions in fossil-fuel use to specifying the use of certain renewable energy technologies. As some agencies have already found out, not all sites or construction projects are created equal. Because many of the requirements are agency-wide, an effective and efficient way to meet these requirements is to consider and identify appropriate locations for these technologies across all agency land and building assets. FEMP can help Federal agencies conduct a renewable energy screening at all of its sites, or just at all of its upcoming construction project

338

West Wide Programmatic Environmental Impact Statement Record...  

Open Energy Info (EERE)

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

339

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

340

M-BAND IMAGING OF THE HR 8799 PLANETARY SYSTEM USING AN INNOVATIVE LOCI-BASED BACKGROUND SUBTRACTION TECHNIQUE  

SciTech Connect (OSTI)

Multi-wavelength observations/spectroscopy of exoplanetary atmospheres are the basis of the emerging exciting field of comparative exoplanetology. The HR 8799 planetary system is an ideal laboratory to study our current knowledge gap between massive field brown dwarfs and the cold 5 Gyr old solar system planets. The HR 8799 planets have so far been imaged at J- to L-band, with only upper limits available at M-band. We present here deep high-contrast Keck II adaptive optics M-band observations that show the imaging detection of three of the four currently known HR 8799 planets. Such detections were made possible due to the development of an innovative LOCI-based background subtraction scheme that is three times more efficient than a classical median background subtraction for Keck II AO data, representing a gain in telescope time of up to a factor of nine. These M-band detections extend the broadband photometric coverage out to {approx}5 {mu}m and provide access to the strong CO fundamental absorption band at 4.5 {mu}m. The new M-band photometry shows that the HR 8799 planets are located near the L/T-type dwarf transition, similar to what was found by other studies. We also confirm that the best atmospheric fits are consistent with low surface gravity, dusty, and non-equilibrium CO/CH{sub 4} chemistry models.

Galicher, Raphael; Marois, Christian [National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC, V9E 2E7 (Canada); Macintosh, Bruce; Konopacky, Quinn [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States); Barman, Travis, E-mail: raphael.galicher@nrc-cnrc.gc.ca [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)

2011-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "wide band gap" from the National Library of EnergyBeta (NLEBeta).
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341

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

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

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 Quasi-optical...

342

Dipolon theory of energy gap parameters in high-temperature superconductors at zero temperature  

Science Journals Connector (OSTI)

Many-body field-theoretic techniques involving dipolon propagator and electron Green’s function have been used to derive the general expressions at zero temperature for the renormalized energy gap parameter ?(k?,?), the gap renormalization parameter Z(k?,?), and energy band renormalization parameter ?(k?,?) for momentum k? and frequency ?. The present theory takes into account explicitly the dressed dipolons as mediators of superconductivity, the screened Coulomb repulsion, and nonrigid electron energy bands considering retardation and damping effects and electron-hole asymmetry. For superconducting cuprates it has been shown by symmetry considerations that, in the lowest order approximations, there exists two energy gap parameters, one being antisymmetric (as) with respect to the exchange of the kx and ky components of vector k? and the other being symmetric (s) with respect to the exchange of kx and ky. The antisymmetric solution is a dx2-y2 wave (i.e., ? [cos(kx)-cos(ky)]) which changes sign with respect to the exchange of kx and ky, and the symmetric solution which is highly asymmetric s wave or equivalently, a combination of a symmetric s wave and absolute value of dx2-y2 wave (i.e. ? | [cos(kx)-cos(ky)] | ) which does not change sign with respect to the exchange of kx and ky. Our self-consistent calculations of the real and imaginary parts of ?(k?,?), Z(k?,?), and ?(k?,?) verify the existence of these two (different) solutions and lead to the conclusion that the antisymmetric solution of the gap parameter corresponds to the observed regular (reg) superconducting energy gap whereas the symmetric solution corresponds to the observed pseudo (pse) energy gap. Calculations have been made for Bi2Sr2CaCu2O8+? as well as Bi2Sr2CaCu2O8. Explicitly, for Bi2Sr2CaCu2O8+? superconductor our calculated values of the antisymmetric and symmetric energy gap parameters are ?0as=22±15?meV and ?1s=30±10?meV with ?0s=1.5±1.5?meV, where ?as(k?)=?0as [cos(kx)-cos(ky)] and ?s(k?)=?0s+?1s| [cos(kx)-cos(ky)] |, in agreement with the corresponding experimental results ?0reg=16.5±1.5?meV, ?1pse?24?meV, and ?0pse=-0.5±2.5?meV. For Bi2Sr2CaCu2O8 superconductor our calculated values of the antisymmetric and the symmetric energy gap parameters are ?0as=24±13?meV and ?1s=29±15?meV with ?0s?0 which also agree with the corresponding experimental results ?0reg=16.5±1.5?meV and ?1pse=30-40?meV with ?0pse=-0.5±2.5?meV. Our calculations also indicate that the bosonic energy relevant to superconductivity in Bi2Sr2CaCu2O8+? superconductor is about 60 meV arising from O1,2 dipolon excitations and that the broad bands observed in optical experiments are due to O1,1, O1,2, and O3 dipolon excitations. Relative contributions from the various dipolon modes have been analyzed. One finds that the symmetric longitudinal modes of oxygen dipolons contribute dominantly in energy gap parameters. The uncertainties in the calculated values of the various parameters are due to uncertainties in the values of the polarizability particularly of oxygen ions, the shielding parameter, the repulsive Coulomb energy, and due to the calculational errors. The origin of the experimentally deduced T* values has been discussed in terms of the present theory which reveals that T* is greater than Tc and that they have the same physical origin.

R. R. Sharma

2001-01-03T23:59:59.000Z

343

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

344

Software Quality Assurance Improvment Plan: ALOHA Gap Analysis, Final Report  

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

Final-ALOHA Final-ALOHA Defense Nuclear Facilities Safety Board Recommendation 2002-1 Software Quality Assurance Improvement Plan Commitment 4.2.1.3: Software Quality Assurance Improvement Plan: ALOHA Gap Analysis Final Report U.S. Department of Energy Office of Environment, Safety and Health 1000 Independence Ave., S.W. Washington, DC 20585-2040 May 2004 ALOHA Gap Analysis May 2004 Final Report INTENTIONALLY BLANK ii ALOHA Gap Analysis May 2004 Final Report FOREWORD This report documents the outcome of an evaluation of the Software Quality Assurance (SQA) attributes of the chemical source term and atmospheric dispersion computer code, ALOHA 5.2.3, relative to established

345

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

346

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

347

Highly Mismatched Alloys for Intermediate Band Solar Cells  

E-Print Network [OSTI]

single-junction intermediate band solar cells. Figure 5:conversion efficiency for a solar cell fabricated from a Znfor Intermediate Band Solar Cells W. Walukiewicz 1 , K. M.

2005-01-01T23:59:59.000Z

348

Evidence for a wide continuum of polymorphs in a-SiO2  

Science Journals Connector (OSTI)

The irradiations of vitreous amorphous silica with subband-gap laser radiation at 248 nm induces reversible-irreversible compaction. The former is consistent with the creation of a wide continuum of densified amorphous silica (a-SiO2) polymorphs whilst the second stage corresponds to the ablation through laser radiation of the damaged a-SiO2. These observations are discussed in terms of conformational structure modifications (i.e., changes in the distribution of planar rings) and stable superficial defect creation.

C. Fiori and R. A. B. Devine

1986-02-15T23:59:59.000Z

349

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

350

Antiferromagnetism in Narrow-Band Solids  

Science Journals Connector (OSTI)

The single-band Hubbard Hamiltonian is examined in the limit of bandwidth much less than intraatomic Coulomb interaction of electrons. We make use of the canonical transformation and "spectral decomposition" of the electron creation operators proposed by Harris and Lange to write down a Green's function which describes electrons in the lower of the split bands of Hubbard's solution. The equation of motion is solved using the moment-conserving decoupling approximation of Tahir-Kheli and Jarrett. We find within our approximation that it is impossible to have an antiferromagnetic state for other than one electron per site. To remedy this defect of the single-band model, we investigate a simplified two-band model in the limit of intra-atomic Coulomb and exchange interaction much greater than the bandwidth, and find that antiferromagnetism is possible for the two nearly half-filled bands. We also discuss effects of the antiferromagnetic ordering on the conductivity in our simplified model and discuss applicability of the theory to real transition metals and transition-metal oxides.

J. B. Sokoloff

1970-02-01T23:59:59.000Z

351

Buffalo Gap II Wind Farm | Open Energy Information  

Open Energy Info (EERE)

Gap II Wind Farm Gap II Wind Farm Jump to: navigation, search Name Buffalo Gap II Wind Farm Facility Buffalo Gap II Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Developer AES Corp. Energy Purchaser Direct Energy Location Taylor County TX Coordinates 32.310556°, -100.149167° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":32.310556,"lon":-100.149167,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

352

Olene Gap Space Heating Low Temperature Geothermal Facility | Open Energy  

Open Energy Info (EERE)

Olene Gap Space Heating Low Temperature Geothermal Facility Olene Gap Space Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Olene Gap Space Heating Low Temperature Geothermal Facility Facility Olene Gap Sector Geothermal energy Type Space Heating Location Klamath County, Oregon Coordinates 42.6952767°, -121.6142133° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[]}

353

Closing the Gender Gap in Energy Policy | Department of Energy  

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

the Gender Gap in Energy Policy the Gender Gap in Energy Policy Closing the Gender Gap in Energy Policy April 7, 2011 - 3:07pm Addthis Melanie A. Kenderdine Melanie A. Kenderdine Director of the Office of Energy Policy and Systems Analysis What are the key facts? There's not just a shortage of women in technical energy-related fields, there's also a shortage of women in energy policy. Women hold only 27 percent of the science and engineering jobs in the United States. Editor's Note: Join the conversation surrounding this year's Clean Energy Ministerial on Twitter via #CEM2. There's a well-documented gender gap for women in science and engineering, or women in the "STEM" fields of science, technology, engineering and math. The numbers are stark: According to the National Science Foundation, women hold only 27 percent of the science and

354

Suicide mortality gap between Francophones and Anglophones of Quebec, Canada  

Science Journals Connector (OSTI)

Few studies evaluate language-group differences in suicide mortality. This study assessed the suicide mortality gap between Francophones and Anglophones of Quebec, Canada according to age, sex, method...

Stephanie Burrows; Nathalie Auger…

2013-07-01T23:59:59.000Z

355

Governing the gap: Forging safe science through relational regulation  

E-Print Network [OSTI]

Designed to close the ubiquitous gap between law on the books and law in action, management systems locate the standard setting and implementation of regulation within the regulated organization itself. Despite efforts to ...

Huising, Ruthanne

356

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

357

SciTech Connect: Enhanced Superconducting Gaps in Trilayer High...  

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

Enhanced Superconducting Gaps in Trilayer High-Temperature Bi (2) Sr (2) Ca (2) Cu (3) O (10+delta) Cuprate Superconductor Citation Details In-Document Search Title: Enhanced...

358

Columbia Gorge Gap Winds: Their Climatological Influence and Synoptic Evolution  

Science Journals Connector (OSTI)

This paper quantifies the impact of the Columbia Gorge on the weather and climate within and downstream of this mesoscale gap and examines the influence of synoptic-scale flow on gorge weather. Easterly winds occur more frequently and are ...

Justin Sharp; Clifford F. Mass

2004-12-01T23:59:59.000Z

359

References on Spectral Gaps, May 2006, Palo Alto, CA  

E-Print Network [OSTI]

gaps for Schödinger operators with symmetric single well potentials and related ... [21] S. G. Bobkov, Isoperimetric and Analytic Inequalities for Log-Concave. Probability .... Mathematical Physics (Birmingham, Alabama, 1986), Lect. Notes in

2006-05-19T23:59:59.000Z

360

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

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

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...

362

Beneath the surface: The decline in gender injury gap  

Science Journals Connector (OSTI)

Abstract Gender differences in the labor market are typically measured by the wage gap. In this paper, we investigate how extending the analysis to an additional job amenity, namely workplace safety, may shed new light on the evolution of gender differences. Our results show that focusing on one unique measure of the gender gap may provide a biased view of the actual progress of women in the labor market. In our data, a significant reduction in the wage gap has been accompanied by a relative increase in injury risk for some groups of workers, e.g. low-skilled female workers. The decreased gender wage gap for these workers does not necessarily imply an overall improvement in their labor market outcomes.

Tiziano Razzolini; Roberto Leombruni; Giovanni Mastrobuoni; Mario Pagliero

2014-01-01T23:59:59.000Z

363

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.

364

Draft Site-Wide Environmental Impact Statement  

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

Site-Wide Environmental Impact Statement Site-Wide Environmental Impact Statement for the Y-12 National Security Complex October 2009 U.S. Department of Energy National Nuclear Security Administration Y-12 Site Office DOE/EIS-0387 COVER SHEET RESPONSIBLE AGENCY: United States (U.S.) Department of Energy (DOE), National Nuclear Security Administration (NNSA) TITLE: Draft Site-wide Environmental Impact Statement for the Y-12 National Security Complex (DOE/EIS-0387) (Draft Y-12 SWEIS) CONTACT: For further information on this SWEIS, For general information on the DOE contact: National Environmental Policy Act (NEPA) process, contact: Pam Gorman Carol Borgstrom, Director Y-12 SWEIS Document Manager Office of NEPA Policy and Compliance, GC-20 Y-12 Site Office U.S. Department of Energy

365

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

366

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

367

Taylor Vortices in Wide Spherical Shells  

Science Journals Connector (OSTI)

It was believed that no Taylor vortices would exist in wide spherical shells with an aspect ratio of ?>0.24. In contrast, we have experimentally generated Taylor vortices in a relatively wide spherical shell with ?=0.33 using some special initial conditions. It is found that the Taylor vortices remain very stable in a range of the Reynolds number 467

M. Liu, C. Blohm, C. Egbers, P. Wulf, and H. J. Rath

1996-07-08T23:59:59.000Z

368

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

369

Radiative Heating in Underexplored Bands Campaign (RHUBC)  

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

Bands Campaign (RHUBC) D. Turner and E. Mlawer RHUBC Breakout Session 2008 ARM Science Team Meeting 13 March, 2008 Norfolk, Virginia Motivation * Radiative heating/cooling in the mid-troposphere modulate the vertical motions of the atmosphere - This heating/cooling occurs primarily in water vapor absorption bands that are opaque at the surface * Approximately 40% of the OLR comes from the far-IR * Until recently, the observational tools were not available to evaluate the accuracy of the far-IR radiative transfer models - Spectrally resolved far-IR radiances, accurate PWV * Need to validate both clear sky (WV) absorption and cirrus scattering properties in these normally opaque bands Scientific Objectives * Conduct clear sky radiative closure studies in order to reduce uncertainties

370

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

E-Print Network [OSTI]

and improve the reliability of systems. Our thermal control framework unifies temperature control mechanisms supply, etc.) to operate less efficiently. Third, high temperatures can trigger thermal emergenciesSystem-level, Unified In-band and Out-of-band Dynamic Thermal Control Dong Li* , Rong Ge** , Kirk

371

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

372

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

373

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

374

Utilization of the world wide web  

Science Journals Connector (OSTI)

Two aspects of utilization of the World Wide Web are examined: (i) the communication of technical data through web cites that provide repositories of atomic and molecular data accessible through searchable databases; and (ii) the communication about issues of mutual concern among data producers data compilers and evaluators and data users.

Peter Mohr; Gary Mallard; Uri Ralchenko; David Schultz

1998-01-01T23:59:59.000Z

375

Band structure of doubly-odd nuclei around mass 130  

SciTech Connect (OSTI)

Nuclear structure of the doublet bands in the doubly-odd nuclei with mass A{approx}130 is studied in terms of a pair-truncated shell model. The model reproduces quite well the energy levels of the doublet bands and the electromagnetic transitions. The analysis of the electromagnetic transitions reveals new band structure of the doublet bands.

Higashiyama, Koji [Department of Physics, Chiba Institute of Technology, Narashino, Chiba 275-0023 (Japan); Yoshinaga, Naotaka [Department of Physics, Saitama University, Saitama City 338-8570 (Japan)

2011-05-06T23:59:59.000Z

376

model strongly interacting particles as rubber bands.  

E-Print Network [OSTI]

model strongly interacting particles as rubber bands. Nothing is perfect, of course. Some relativity, there is a tempta- tion to carry intelligent design to an ex- treme in which God wrote (recall Bohr's admonition, "Stop telling God what to do!"). The landscape picture derails this thinking

Hughes, Kim

377

The ‘Wave Band' Theory of Wireless Transmission  

Science Journals Connector (OSTI)

... the tuned circuit, namely, that the really selective circuit does cut off the higher audio frequencies, generally explained by the ‘cutting of the side bands’ What is actually ... its excitation has ceased. If it is excited by a carrier modulated by a high audio frequency, the persistence of its vibrations will not allow the amplitude of these to ...

A. A. NEWBOLD

1930-03-01T23:59:59.000Z

378

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

379

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

380

DFAS Wide-Area Workflow Issues  

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

DFAS Wide-Area Workflow DFAS Wide-Area Workflow Issues Mark Shvartzman Sr. Project Manager, CEM, CEA Southern California Edison Presented at the Spring FUPWG Meeting April 20, 2011 What We Are Going to Discuss * Review Delivery Order or Task Order for accounting lines information. * Contact Contracting Officer or Contracting specialist and request Pay DoDAAC and Ext. information * Create Payment Log by ACRN * Start creating Invoice How the WAWF works and how to navigate through: 2 CONTRACT N68711-03-G-4019 DO#0028 Pay Records Bill by CLIN Award $ by CLIN Billed To Date Invoice number Pay Total Balance by CLIN 7500009733 $330,899.11 CLIN 0001AA 674,220.00 674,220.00 7500009733 7500012596 674,220.00 0.00 7500012596 $641,344.69 CLIN 0001AB 325,780.00 298023.8 27,756.20 7500012596 7500015079 325,780.00

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.


381

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

382

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

383

Buffalo Gap 3 Wind Farm | Open Energy Information  

Open Energy Info (EERE)

Buffalo Gap 3 Wind Farm Buffalo Gap 3 Wind Farm Facility Buffalo Gap 3 Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner AES Wind Generation Developer AES Wind Generation Energy Purchaser Direct Energy Location TX Coordinates 32.310556°, -100.149167° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":32.310556,"lon":-100.149167,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

384

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

385

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

386

Origin of the charge gap in LaMnPO  

Science Journals Connector (OSTI)

We present high temperature inelastic neutron scattering and magnetic susceptibility measurements of the antiferromagnetic insulator LaMnPO that are consistent with the presence of two-dimensional magnetic correlations up to a temperature Tmax?700K?TN=375 K, the Néel temperature. Optical transmission measurements show the T=300 K direct charge gap ?=1 eV has decreased only marginally by 500 K and suggest it decreases by only 10% at Tmax. Density functional theory and dynamical mean-field theory calculations reproduce a direct charge gap in paramagnetic LaMnPO only when a strong Hund's coupling JH=0.9 eV is included, as well as on-site Hubbard U=8 eV. Our results show that LaMnPO is a Mott-Hund's insulator, in which the charge gap is rather insensitive to antiferromagnetic exchange coupling.

D. E. McNally; J. W. Simonson; K. W. Post; Z. P. Yin; M. Pezzoli; G. J. Smith; V. Leyva; C. Marques; L. DeBeer-Schmitt; A. I. Kolesnikov; Y. Zhao; J. W. Lynn; D. N. Basov; G. Kotliar; M. C. Aronson

2014-11-18T23:59:59.000Z

387

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

388

WORKSHOP REPORT:Light-Duty Vehicles Technical Requirements and Gaps for Lightweight and Propulsion Materials  

Broader source: Energy.gov [DOE]

WORKSHOP REPORT:Light-Duty Vehicles Technical Requirements and Gaps for Lightweight and Propulsion Materials

389

Quantifying yield gaps in wheat production in Russia  

Science Journals Connector (OSTI)

Crop yields must increase substantially to meet the increasing demands for agricultural products. Crop yield increases are particularly important for Russia because low crop yields prevail across Russia's widespread and fertile land resources. However, reliable data are lacking regarding the spatial distribution of potential yields in Russia, which can be used to determine yield gaps. We used a crop growth model to determine the yield potentials and yield gaps of winter and spring wheat at the provincial level across European Russia. We modeled the annual yield potentials from 1995 to 2006 with optimal nitrogen supplies for both rainfed and irrigated conditions. Overall, the results suggest yield gaps of 1.51–2.10 t ha?1, or 44–52% of the yield potential under rainfed conditions. Under irrigated conditions, yield gaps of 3.14–3.30 t ha?1, or 62–63% of the yield potential, were observed. However, recurring droughts cause large fluctuations in yield potentials under rainfed conditions, even when the nitrogen supply is optimal, particularly in the highly fertile black soil areas of southern European Russia. The highest yield gaps (up to 4 t ha?1) under irrigated conditions were detected in the steppe areas in southeastern European Russia along the border of Kazakhstan. Improving the nutrient and water supply and using crop breeds that are adapted to the frequent drought conditions are important for reducing yield gaps in European Russia. Our regional assessment helps inform policy and agricultural investors and prioritize research that aims to increase crop production in this important region for global agricultural markets.

Florian Schierhorn; Monireh Faramarzi; Alexander V Prishchepov; Friedrich J Koch; Daniel Müller

2014-01-01T23:59:59.000Z

390

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

391

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

392

An investigation on reliable passivation of GaP  

E-Print Network [OSTI]

reports the results of a study of sputtered Silicon Nitride 3N4) and Anodic Oxide as passivating techniques for Gallium Phosphide. Anodic Oxide was grown on GaP by anodizing the semiconductor in 30% hydrogen peroxide. The resulting oxide had an index... reports the results of a study of sputtered Silicon Nitride 3N4) and Anodic Oxide as passivating techniques for Gallium Phosphide. Anodic Oxide was grown on GaP by anodizing the semiconductor in 30% hydrogen peroxide. The resulting oxide had an index...

Greaves King, Carlos A.

2012-06-07T23:59:59.000Z

393

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

394

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

395

S-Band Loads for SLAC Linac  

SciTech Connect (OSTI)

The S-Band loads on the current SLAC linac RF system were designed, in some cases, 40+ years ago to terminate 2-3 MW peak power into a thin layer of coated Kanthal material as the high power absorber [1]. The technology of the load design was based on a flame-sprayed Kanthal wire method onto a base material. During SLAC linac upgrades, the 24 MW peak klystrons were replaced by 5045 klystrons with 65+ MW peak output power. Additionally, SLED cavities were introduced and as a result, the peak power in the current RF setup has increased up to 240 MW peak. The problem of reliable RF peak power termination and RF load lifetime required a careful study and adequate solution. Results of our studies and three designs of S-Band RF load for the present SLAC RF linac system is discussed. These designs are based on the use of low conductivity materials.

Krasnykh, A.; Decker, F.-J.; /SLAC; LeClair, R.; /INTA Technologies, Santa Clara

2012-08-28T23:59:59.000Z

396

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

397

Alternating parity bands in 87218Fr  

Science Journals Connector (OSTI)

States in doubly odd 218Fr have been studied using in-beam spectroscopy ?-?-? coincidence techniques mainly through the 209Bi(18O, 2?n) reaction at 94 MeV bombarding energy, using the 8? GASP-ISIS spectrometer at Legnaro. 218Fr shows a band structure, with interleaved states of alternating parities connected by enhanced E1 transitions. Tentative spin assignment and the relation between the structure of 218Fr and its isotone 220Ac is discussed.

M. E. Debray; M. A. Cardona; D. Hojman; A. J. Kreiner; M. Davidson; J. Davidson; H. Somacal; G. Levinton; D. R. Napoli; S. Lenzi; G. de Angelis; M. De Poli; A. Gadea; D. Bazzacco; C. Rossi-Alvarez; N. Medina

2000-07-10T23:59:59.000Z

398

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

399

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

400

Wide Bandgap Semiconductors for Clean Energy Workshop  

Broader source: Energy.gov [DOE]

A workshop on Wide Bandgap (WBG) Semiconductors for Clean Energy (held July 25, 2012, in Chicago, Illinois) brought together stakeholders from industry and academia to discuss the technical status of WBG semiconductors. The workshop also explored emerging WBG market applications in clean energy and barriers to the development and widespread commercial use of WBG semiconductors. Improving the quality and reliability of WBG semiconductors—and reducing their manufacturing costs—could accelerate their use in automotive, power electronics, solid-state lighting, and other clean energy applications.

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

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

402

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

403

EA-1422: Final Site-wide Environmental Assessment | Department...  

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

2: Final Site-wide Environmental Assessment EA-1422: Final Site-wide Environmental Assessment Sandia National Laboratories Sandia National Laboratories (SNL) is one of three...

404

Wide Bandgap Semiconductors for Clean Energy Workshop Agenda  

Energy Savers [EERE]

Wide Bandgap Semiconductors for Clean Energy Workshop Wednesday, July 25, 2012 Hilton Rosemont O'Hare, Chicago, IL Introduction Wide bandgap (WBG) semiconductors operate at...

405

Webinar: Opportunities for Wide Bandgap Semiconductor Power Electronic...  

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

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

406

Webinar: Opportunities for Wide Bandgap Semiconductor Power Electronic...  

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

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

407

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...

408

EIS-0309: Final Site-Wide Environmental Impact Statement | Department...  

Energy Savers [EERE]

Final Site-Wide Environmental Impact Statement EIS-0309: Final Site-Wide Environmental Impact Statement The Department of Energy (DOE) limits electronic access to certain NEPA...

409

DOE Issues Final Site-Wide Environmental Impact Statement for...  

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

410

EIS-0309: Draft Site-Wide Environmental Impact Statement | Department...  

Office of Environmental Management (EM)

Draft Site-Wide Environmental Impact Statement EIS-0309: Draft Site-Wide Environmental Impact Statement The Department of Energy (DOE) limits electronic access to certain NEPA...

411

EIS-0281: Final Site-Wide Environmental Impact Statement | Department...  

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

Final Site-Wide Environmental Impact Statement EIS-0281: Final Site-Wide Environmental Impact Statement Sandia National LaboratoriesNew Mexico DOE proposes to continue operating...

412

Bridging the Efficiency Gap: Commercial Packaged Rooftop Air Conditioners  

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

Bridging the Efficiency Gap: Commercial Packaged Rooftop Air Conditioners Bridging the Efficiency Gap: Commercial Packaged Rooftop Air Conditioners Title Bridging the Efficiency Gap: Commercial Packaged Rooftop Air Conditioners Publication Type Conference Proceedings Year of Publication 2000 Authors Shugars, John, Philip Coleman, Christopher T. Payne, and Laura Van Wie McGrory Conference Name Proceedings from the 2000 ACEEE Summer Study on Energy Efficiency in Buildings Volume 10 Pagination 217-226 Date Published 01/2000 Abstract The energy efficiency ofmany products has increased markedly over the past decade. A conspicuous exception to this trend is commercialpackaged rooftop air conditioners, which have experiencedlittle to no efficiency improvement since 1992 when the Energy Policy Act of 1992 imposed federal minimum standards. Packaged rooftop units have been estimated to use on the order of76 billion kWh annually in the US, at a cost ofroughly $5.6 billion. Sales of these units are growing, and the majority of units sold have energy efficiency ratios (EERs) at orjust above the current national minimum efficiency standards. In this paper we document the static efficiencies ofcommercialpackaged air conditioners, explore the reasons behindthis efficiency gap, and assess opportunities for overcoming the barriers to efficiency improvements in these products.

413

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

414

RIFLE GAP RESERVOIR FISHERY INVESTIGATION Photo: Willow Hibbs  

E-Print Network [OSTI]

in western Colorado, hosts a popular recreational fishery. Historically, stocked rainbow and brown trout have Department of Fish, Wildlife and Conservation Biology, Colorado State University Tel: 970-491-5002 email, Wildlife and Conservation Biology, Colorado State University March 2009 #12;Rifle Gap Reservoir Fishery

415

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.

416

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

417

Metal multilayer mirrors for EUV wide field telescopes  

SciTech Connect (OSTI)

Metal multilayer mirrors have been designed for the ALEXIS satellite, which is to carry six wide field telescopes to perform an all-sky survey in three or four narrow wavelength bands in the EUV. Comprised of alternating layers of molybdenum and silicon, the mirrors are optimized to provide maximum reflectivity at angles from 11.5 to 17/degree/ off normal incidence and at wavelengths of 133, 171, or 186A. Simultaneously, the mirrors use a ''wavetrap'' described below to suppress reflectivity at 304A, where the extremely strong geocoronal line of He II causes severe background problems. Low reflectivity at 304A is achieved by superposing two layer pairs that provide destructive interference with an effective 2d spacing of 152A. The Mo layers in this wavetrap must be very thin, about 10A each, in order to allow the shorter wavelengths desired for peak reflectivity to penetrate without significant attenuation. Because refraction changes the effective angle of passage through the wavetrap, a joint optimization between layer thicknesses in the deep layers and the wavetrap layers must be performed for each target peak wavelength. For the 186A mirror, the optimum design from substrate upward is 40 layer pairs, each 74A Si and 31A Mo, followed by 2 layer pairs, each 55A Si and 10A Mo. Calculations predict this design will have a peak reflectivity at 186A of 35 percent and a 304A reflectivity less than 10/sup /minus/5/, if available optical constants are correct and the multilayer can be fabricated without difficulty. We will present details of the calculations and laboratory measurements of the reflectivity performance attained with prototype mirrors. 6 refs., 2 figs.

Smith, B.W.; Bloch, J.J.; Roussel-Dupre,D.

1989-01-01T23:59:59.000Z

418

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

419

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.

420

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

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.


421

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

422

Vehicle Technologies Office: Fact #516: April 28, 2008 The Petroleum Gap  

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

6: April 28, 6: April 28, 2008 The Petroleum Gap to someone by E-mail Share Vehicle Technologies Office: Fact #516: April 28, 2008 The Petroleum Gap on Facebook Tweet about Vehicle Technologies Office: Fact #516: April 28, 2008 The Petroleum Gap on Twitter Bookmark Vehicle Technologies Office: Fact #516: April 28, 2008 The Petroleum Gap on Google Bookmark Vehicle Technologies Office: Fact #516: April 28, 2008 The Petroleum Gap on Delicious Rank Vehicle Technologies Office: Fact #516: April 28, 2008 The Petroleum Gap on Digg Find More places to share Vehicle Technologies Office: Fact #516: April 28, 2008 The Petroleum Gap on AddThis.com... Fact #516: April 28, 2008 The Petroleum Gap In 1989 the transportation sector petroleum consumption surpassed U.S. petroleum production for the first time, creating a gap that must be met

423

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

424

Coriolis Interaction Between Three Nilsson Bands in Pa  

Science Journals Connector (OSTI)

By comparing new experimental results with calculations, it is shown that the levels above the ½ [5,- 3, 0] ground-state band in Pa233 and Pa231 may be interpreted as resulting from the ½+[6, 6, 0], the 32+[6,5,1], and the 52+[6,4,2] bands involved in a three-band Coriolis interaction.

W. Hoekstra and A. H. Wapstra

1969-04-21T23:59:59.000Z

425

k?p theory of energy bands, wave functions, and optical selection rules in strained tetrahedral semiconductors  

Science Journals Connector (OSTI)

This paper examines an eight-band k?p theory of strained semiconductors yielding energy bands, wave functions, and momentum matrices. Only if the symmetry of the strained crystal is accounted for in all terms of the Hamiltonian, a consistent definition and calculation of the momentum matrix becomes possible. The band structure and wave functions are nonanalytical functions of strain and crystal momentum. For strained crystals, the extrapolation from the ? point into the Brillouin zone, such as the effective-mass approximation for the optical-matrix elements, can be misleading. For certain cases, the heavy- and light-hole isoenergetic surfaces form complex figures resembling the indicatrix of birefringent biaxial crystals. The symmetry of the hole wave functions causes dichroism for photon energies close to the gap energy, while the crystal becomes optically isotropic for larger photon energies. Numerical results are presented for the eight-band k?p model of biaxially strained bulklike 1.3-?m–InxGa1-xAsyP1-y on InP being an important material in optoelectronics.

P. Enders; A. Bärwolff; M. Woerner; D. Suisky

1995-06-15T23:59:59.000Z

426

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

427

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

428

Band magnetism in the Hubbard model  

Science Journals Connector (OSTI)

A self-consistent moment method is applied to the Hubbard model in order to find out under what circumstances spontaneous band magnetism may occur. The theory is formulated for a two-sublattice structure to treat simultaneously para-, ferro-, and antiferromagnetic systems. The starting point is a two-pole ansatz for the one-electron spectral density, the free parameters of which are fitted by equating exactly calculated spectral moments. All correlation functions appearing in the moments can be expressed by the spectral density, guaranteeing therewith a closed system of equations, which can be solved self-consistently for the average particle numbers ?ni?? and ?ni??. A T=0 phase diagram is presented in terms of band occupation n (0?n?2) and Coulomb interaction U. Ferromagnetic solutions appear only if n exceeds a critical occupation ncFM and U a minimum value Umin. For antiferromagnetic solutions a critical U does not exist, but a critical band occupation ncAFM does.Antiferromagnetism is stable in a restricted region of n around n=1, which is broadest for intermediate couplings (U/W?1, W being the Bloch bandwidth) and shrinks to the n=1 axis for strong couplings (U/W??). For smaller n, but n>ncFM and sufficiently high U (U>W), ferromagnetism is stable, while for low band occupations the system is paramagnetic irrespective of U. The critical temperatures TC and TN are strongly U and n dependent. For fixed n, TC increases with U, but saturates for U?? at finite values (500–800 K), while TN has a maximum at an intermediate U value (U?W). First-order as well as second-order transitions are observed. Ferromagnetic order arises mainly because of a shift of ? and ? quasiparticle subbands. In antiferromagnets, corresponding ? and ? subbands occupy exactly the same energy regions, but with different state densities. The magnetic behavior of the Hubbard model can be understood as a direct consequence of the sensitive (T,n,U) dependence of the quasiparticle density of states, which is therefore discussed in detail.

W. Nolting and W. Borgiel/

1989-04-01T23:59:59.000Z

429

Band Structure of {sup 85}Sr  

SciTech Connect (OSTI)

High spin states in {sup 85}Sr were populated using the reaction {sup 76}Ge({sup 13}C, 4n) at a beam energy of 52 MeV. Gamma-gamma coincidence measurements along with investigation of directional correlation ratios were utilized to establish the extended level scheme upto I{sup {pi}}= (35/2{sup -}). One of the positive parity states observed at 3383.3 keV ((I{sup {pi}}= 19/2{sup (+)}) may be considered as a magnetic rotational ({Delta}I = 1) band, the negative parity states built on 3028.0 level show an irregular behaviour and does not exhibit magnetic rotation.

Kumar, Suresh; Mandal, S. K. [Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India); Jain, A. K. [Department of Physics, Indian Institute of Technology, Roorkee-247667 (India); Chaturvedi, L. [Guru Ghasidas University, Bilaspur, Chhattisgarh-495009 (India); Sinha, Rishi Kumar [Department of Physics, Banaras Hindu University, Varanasi-221005 (India); Negi, Dinesh; Dhal, Ankul; Kumar, R.; Singh, R. P.; Muralithar, S.; Bhowmik, R. K.; Pancholi, S. C. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, Delhi-110067 (India)

2010-11-24T23:59:59.000Z

430

The effects of enforcement on the behavior of citizen band and non-citizen band radio equipped vehicles  

E-Print Network [OSTI]

THE EFFECTS OF ENFORCEMENT ON 1HE BEHAVIOR OF CITIZEN BAND AND NON-CITIZEN BAND RADIO EQUIPPED VEHICLES A Thesis by Donald Ray Harrison Submitted to the Graduate College of Texas ASM University i n partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1978 Major Subject: Industrial Engineering THE EFFECTS OF ENFORCEMENT ON THE BEHAVIOR OF CITIZEN BAND AND NON ? CITIZEN BAND RADIO EQUIPPED VEHICLES A Thesis by DONALD RAY HARRISON Approved as to style and content...

Harrison, Donald Ray

2012-06-07T23:59:59.000Z

431

Ultraviolet - "Green" Energy in the "C" Band  

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

Ultraviolet - "Green" Energy in the "C" Band Ultraviolet - "Green" Energy in the "C" Band Speaker(s): Forrest Fencl Date: April 16, 2009 - 12:00pm Location: 90-3122 Mr. Forrest Fencl of UV Resources, Inc. will discuss how air conditioning system operation, maintenance, and utilization influence system cooling capacity and indoor air quality. The use of ultraviolet germicidal radiation to clean heat exchangers and maintain their efficiency will be reviewed and energy savings estimates will be provided. Additionally, he will discuss why UV-C is considered the "green" cleaner and how widely it is used today as an engineering strategy for precluding the growth, dissemination and recirculation of microbial contaminants. For more information about this seminar, please contact: Bill Fisk(510) 486-591

432

Near-Infrared Classification Spectroscopy: H-band Spectra of Fundamental MK Standards  

E-Print Network [OSTI]

We present a catalogue of H-band spectra for 85 stars of approximately solar abundance observed at a resolving power of 3000 with the KPNO Mayall 4m FTS. The atlas covers spectral types O7-M5 and luminosity classes I-V as defined on the MK system. We identify both atomic and molecular indices and line-ratios which are temperature and luminosity sensitive allowing spectral classification to be carried out in the H-band. The line ratios permit spectral classification in the presence of continuum excess emission, which is commonly found in pre-main sequence and evolved stars. We demonstrate that with spectra of R = 1000 obtained at SNR > 50 it is possible to derive spectral types within +- 2 subclasses for late-type stars. These data are available electronically through the Astronomical Data Center in addition to being served on the World-Wide-Web.

Michael R. Meyer; Suzan Edwards; Kenneth H. Hinkle; Stephen E. Strom

1998-08-19T23:59:59.000Z

433

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

434

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

435

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

436

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

437

Developing Secure Power Systems Professional Competence: Alignment and Gaps  

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

Developing Secure Power Systems Professional Competence: Alignment Developing Secure Power Systems Professional Competence: Alignment and Gaps in Workforce Development Programs - Phase 2 (July/August 2013) Developing Secure Power Systems Professional Competence: Alignment and Gaps in Workforce Development Programs - Phase 2 (July/August 2013) DOE has recognized that the electricity industry needs workforce development resources that can aid in the accelerating need for Secure Power Systems Professionals, while at the same time identifying capabilities and competencies to protect and enable the modernized grid currently being built. In the spring of 2011 a project was initiated to identify those capabilities and competencies along with assessing the need and qualifications for a certification program for Secure Power Systems

438

Microsoft Word - IMBA Gap Analysis Final 20060831.doc  

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

DOE/EH-0711 DOE/EH-0711 Gap Analysis for IMBA and DOE Safety Software Central Registry Recommendation Final U.S. Department of Energy Office of Environment, Safety and Health 1000 Independence Avenue, S.W. Washington, D.C. 20585-2040 August 2006 DOE/EH-0711 i INTENTIONALLY BLANK DOE/EH-0711 ii FOREWORD This report documents the outcome of an evaluation of the safety software quality assurance attributes of the Integrated Modules for Bioassay Analysis (IMBA) Expert (tm) USDOE-Edition and Professional Plus computer products relative to the safety software requirements identified in DOE O 414.1C, Quality Assurance. This evaluation, a gap analysis, is performed according to DOE G 414.1-4 and is a requisite

439

Pleasant Gap, Pennsylvania: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

Gap, Pennsylvania: Energy Resources Gap, Pennsylvania: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 40.8681177°, -77.7466665° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":40.8681177,"lon":-77.7466665,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

440

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

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

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

442

The information gap in corporate annual reports: evidence from Egypt  

Science Journals Connector (OSTI)

This study explores whether an information gap exists for six types of corporate disclosure in Egypt, where International Accounting Standards (IAS) apply but penalties for non-compliance are limited. It also investigates whether low compliance with mandatory disclosure can be explained by low levels of demand for this type of information among local financial analysts. The results identify a significant gap between actual disclosure practices of companies for various types of disclosure and market perceptions of this practice. Our findings also suggest that low compliance with disclosure requirements in Egypt is not driven by low levels of demand from local financial analysts, because these items of information are perceived as useful for investment decision making.

Omaima A.G. Hassan; Gianluigi Giorgioni; Peter Romilly; David M. Power

2012-01-01T23:59:59.000Z

443

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

444

Technical Standards, CFAST-Gap Analysis - May 3, 2004 | Department of  

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

Gap Analysis - May 3, 2004 Gap Analysis - May 3, 2004 Technical Standards, CFAST-Gap Analysis - May 3, 2004 May 3, 2004 DOE-EH-4.2.1.3-CFAST-Gap Analysis, Software Quality Assurance Improvement Plan: CFAST Gap Analysis This report documents the outcome of an evaluation of the Software Quality Assurance (SQA) attributes of the CFAST computer code for accident analysis applications, relative to established requirements. This evaluation, a "gap analysis," is performed to meet commitment 4.2.1.3 of the Department of Energy's Implementation Plan to resolve SQA issues identified in the Defense Nuclear Facilities Safety Board Recommendation 2002-1. Technical Standards, CFAST-Gap Analysis More Documents & Publications Technical Standards, CFAST-Code Guidance - July 23, 2004 Technical Standards, MELCOR - Gap Analysis - May 3, 2004

445

Vehicle Technologies Office: Fact #414: March 6, 2006 The Petroleum Gap  

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

4: March 6, 2006 4: March 6, 2006 The Petroleum Gap to someone by E-mail Share Vehicle Technologies Office: Fact #414: March 6, 2006 The Petroleum Gap on Facebook Tweet about Vehicle Technologies Office: Fact #414: March 6, 2006 The Petroleum Gap on Twitter Bookmark Vehicle Technologies Office: Fact #414: March 6, 2006 The Petroleum Gap on Google Bookmark Vehicle Technologies Office: Fact #414: March 6, 2006 The Petroleum Gap on Delicious Rank Vehicle Technologies Office: Fact #414: March 6, 2006 The Petroleum Gap on Digg Find More places to share Vehicle Technologies Office: Fact #414: March 6, 2006 The Petroleum Gap on AddThis.com... Fact #414: March 6, 2006 The Petroleum Gap Since 1989, the transportation sector alone has used more petroleum than the United States produces. The current projections indicate that by the

446

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...

447

Nanoscale gap filling for phase change material by pulsed deposition and inductively coupled plasma etching  

Science Journals Connector (OSTI)

The gap filling of phase change material has become a critical module in the fabrication process of phase change random access memory (PCRAM) as the ... . We achieved void free gap filling of phase change material

W. C. Ren; B. Liu; Z. T. Song; X. Z. Jing; B. C. Zhang; Y. H. Xiang…

2013-09-01T23:59:59.000Z

448

Engineered nanomaterials: knowledge gaps in fate, exposure, toxicity, and future directions  

Science Journals Connector (OSTI)

The aim of this study is to identify current knowledge gaps in fate, exposure, and toxicity of engineered nanomaterials (ENMs), highlight research gaps, and suggest future research directions. Humans and other living organisms are exposed to ENMs during ...

Arun Kumar, Prashant Kumar, Ananthitha Anandan, Teresa F. Fernandes, Godwin A. Ayoko, George Biskos

2014-01-01T23:59:59.000Z

449

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

450

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.

451

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

452

Vehicle Technologies Office: Fact #465: April 16, 2007 The Petroleum Gap  

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

5: April 16, 5: April 16, 2007 The Petroleum Gap to someone by E-mail Share Vehicle Technologies Office: Fact #465: April 16, 2007 The Petroleum Gap on Facebook Tweet about Vehicle Technologies Office: Fact #465: April 16, 2007 The Petroleum Gap on Twitter Bookmark Vehicle Technologies Office: Fact #465: April 16, 2007 The Petroleum Gap on Google Bookmark Vehicle Technologies Office: Fact #465: April 16, 2007 The Petroleum Gap on Delicious Rank Vehicle Technologies Office: Fact #465: April 16, 2007 The Petroleum Gap on Digg Find More places to share Vehicle Technologies Office: Fact #465: April 16, 2007 The Petroleum Gap on AddThis.com... Fact #465: April 16, 2007 The Petroleum Gap (Revised April 18, 2007) Since 1989, the transportation sector alone has used more petroleum than

453

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

454

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

455

Electric strength of the accelerating gap of a plasma electron source at rough vacuum  

Science Journals Connector (OSTI)

Conditions for the electric breakdown of the accelerating gap of a plasma electron source are determined. It is shown that,...

V. A. Burdovitsin; M. N. Kuzemchenko; E. M. Oks

2002-07-01T23:59:59.000Z

456

The Origin of the Mercury Bands at 2480A  

Science Journals Connector (OSTI)

The group of eight mercury bands near 2480A was photographed under varied excitation conditions with the purpose of determining their origin. The source was a discharge through mercury vapor produced in a quartz tube through external electrodes by a low-voltage Tesla coil. Five tubes containing distilled mercury and commercial mercury arc lamp showed this group of bands. These bands were weakened by heat along with known mercury bands. The origin is undoubtedly some form of mercury molecule. The most probable forms are Hg2+ and Hg2. Five observations favor Hg2+ over Hg2. (1) These bands have never been observed in fluorescence. (2) The 2476 band is more intense than the 2345 Hg2 band under strong field excitation but weaker than 2345 under low field excitation. (3) No other bands with properties like those of the 2480 group have been observed in the mercury spectrum and Rayleigh has shown that these bands do not occur in absorption. (4) The bands in this group may be classified as sequences v?-v??=0±1±2±3, and a lower limit for D of 0.3 volts estimated. (5) In the v?-v??=0 sequence, emission is observed from state v?=41 indicating molecules with very high vibrational energy. This energy may be supplied by the electric field if the emitter is an ion but not if it is a neutral molecule.

J. Gibson Winans

1932-12-15T23:59:59.000Z

457

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

458

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

459

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

460

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

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

Garbage Collecting the World Wide Web Stephen M. Watt  

E-Print Network [OSTI]

Garbage Collecting the World Wide Web Stephen M. Watt Western University London, Ontario, Canada N6A 5B7 Stephen.Watt@uwo.ca Abstract The World Wide Web has grown over the past decade and a half from

Watt, Stephen M.

462

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

463

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

464

EA-1968: Final Site-Wide Environmental Assessment  

Broader source: Energy.gov [DOE]

National Renewable Energy Laboratory (NREL) South Table Mountain (STM) Campus Site-Wide Environmental Assessment, Golden, Colorado

465

EA-1914: Final Site-Wide Environmental Assessment  

Broader source: Energy.gov [DOE]

National Renewable Energy Laboratory (NREL) National Wind Technology Center (NWTC) Site-Wide Environmental Assessment, Golden, Colorado

466

Lifetime measurements of Triaxial Strongly Deformed bands in $^{163}$Tm  

E-Print Network [OSTI]

With the Doppler Shift Attenuation Method, quadrupole transition moments, $Q_t$, were determined for the two recently proposed Triaxial Strongly Deformed (TSD) bands in $^{163}$Tm. The measured $Q_t$ moments indicate that the deformation of these bands is larger than that of the yrast, signature partners. However, the measured values are smaller than those predicted by theory. This observation appears to be valid for TSD bands in several nuclei of the region

X. wang; R. V. F. Janssens; E. F. Moore; U. Garg; Y. Gu; S. Frauendorf; M. P. Carpenter; S. S. Ghugre; N. J. Hammond; T. Lauritsen; T. Li; G. Mukherjee; N. S. Pattabiraman; D. Seweryniak; S. Zhu

2007-05-14T23:59:59.000Z

467

Character of states near the Fermi level in (Ga,Mn)As: Impurity to valence band crossover RID E-6453-2010  

E-Print Network [OSTI]

We discuss the character of states near the Fermi level in Mn-doped GaAs, as revealed by a survey of dc transport and optical studies over a wide range of Mn concentrations. A thermally activated valence-band contribution to dc transport, a...

Jungwirth, T.; Sinova, Jairo; MacDonald, A. H.; Gallagher, B. L.; Novak, V.; Edmonds, K. W.; Rushforth, A. W.; Campion, R. P.; Foxon, C. T.; Eaves, L.; Olejnik, E.; Masek, J.; Yang, S-R Eric; Wunderlich, J.; Gould, C.; Molenkamp, L. W.; Dietl, T.; Ohno, H.

2007-01-01T23:59:59.000Z

468

Engineering the Electronic Band Structure for Multiband Solar Cells  

Science Journals Connector (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.

N. López; L. A. Reichertz; K. M. Yu; K. Campman; W. Walukiewicz

2011-01-10T23:59:59.000Z

469

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

470

ARM - Radiative Heating in Underexplored Bands Campaign-II (RHUBC...  

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

Eli Mlawer, Principal Investigator Dave Turner, Principal Investigator Radiative Heating in Underexplored Bands Campaign-II (RHUBC-II) At an elevation of more than 5000...

471

ARM - Radiative Heating in Underexplored Bands Campaign (RHUBC...  

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

Contacts News ARM Press Release (Feb. 26, 2007) Images flickrdots Radiative Heating in Underexplored Bands Campaign (RHUBC) Now available: RHUBC-II website Between...

472

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

473

Rapidity gap signals in Higgs-boson production at the SSC  

Science Journals Connector (OSTI)

We examine the structure of the underlying event in neutral Higgs-boson production at the Superconducting Super Collider (SSC). Gaps, regions of rapidity containing no soft particle production, can provide a clean signature for W boson fusion to the heavy Higgs boson. We first examine the physical basis of gap production and estimate the survival probability of gaps in the minijet model. Then, using pythia, and herwig, we compare gap events to W pair production from top quark decay and qq¯ fusion. We find that, if experimental problems can be overcome, gaps should provide a small, but clean, signal for heavy Higgs-boson production at the SSC.

R. S. Fletcher and T. Stelzer

1993-12-01T23:59:59.000Z

474

Gap-dependent transitions of atmospheric microplasma in open air  

SciTech Connect (OSTI)

We report on the gap dependence of the planar atmospheric microplasma in air. We investigate the transitions of the dielectric barrier discharge in open air, including the random walk filaments (plasma columns), localized filaments, stochastic filaments, and diffuse discharge. A star-shaped filamentary discharge pattern is observed after the formation of the localized filaments. The liquid drops found on the dielectric surface further become a confining pattern for star-shaped discharge. We also demonstrate the applications of the insulating pattern for the use of the plasma display in open air by the handwritten characters with UV adhesive.

Chu, Hong-Yu; Huang, Bo-Shiun [Department of Physics, National Chung Cheng University, ChiaYi 62102, Taiwan (China)

2011-04-15T23:59:59.000Z

475

Random-Gap Model for Graphene and Graphene Bilayers  

Science Journals Connector (OSTI)

The effect of a randomly fluctuating gap, created by a random staggered potential, is studied in a monolayer and a bilayer of graphene. The density of states, the one-particle scattering rate, and the transport properties (diffusion coefficient and conductivity) are calculated at the neutrality point. All of these quantities vanish at a critical value of the average staggered potential, signaling a continuous transition to an insulating behavior. Transport quantities are directly linked to the one-particle scattering rate. Although the behavior is qualitatively the same in mono- and bilayers, the effect of disorder is much stronger in the latter.

K. Ziegler

2009-03-24T23:59:59.000Z

476

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

477

Origin of the optical gap in half-doped manganites  

Science Journals Connector (OSTI)

We have analyzed the coexisting charge and orbital ordering in half-doped manganites using a model which includes Coulomb and Jahn-Teller orbital polarization interactions. Most surprisingly, the gap in the optical conductivity is reduced by both on-site and intersite Coulomb interactions, but increases and explains the experimental results when the Jahn-Teller terms with orbital polarization are considered. The origin of this behavior is explained within a molecular model which arises in the limit of extreme topological frustration, when single electrons are confined to molecular units consisting of three orbitals.

Mario Cuoco; Canio Noce; Andrzej M. Ole?

2002-09-25T23:59:59.000Z

478

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

479

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

480

Nonlinear Photon-Assisted Tunneling Transport in Optical Gap Antennas  

Science Journals Connector (OSTI)

(16, 17) For instance, incoming photons can exchange energy with tunneling charges modifying thus the conductance of the barrier(18, 19) and strong-field effects were recently reported. ... (32) The height ? of the potential barriers can be directly deduced from these two minima. ... Two lock-in amplifiers referenced at Fmod and 2Fmod output a signal proportional to the differential conductance I? = Vac(?Ib/?Vb) of the gap antenna and signal proportional to the nonlinearity of the conductance I? = 1/4Vac2(?2Ib/?Vb2), respectively. ...

Arnaud Stolz; Johann Berthelot; Marie-Maxime Mennemanteuil; Gérard Colas des Francs; Laurent Markey; Vincent Meunier; Alexandre Bouhelier

2014-04-03T23:59:59.000Z

Note: This page contains sample records for the topic "wide band gap" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


481

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

482

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-Nuñez, L; Galadi-Enriquez, D

2004-01-01T23:59:59.000Z

483

Technical Standards, MACCS2, Gap Analysis - May 3, 2004 | Department of  

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

MACCS2, Gap Analysis - May 3, 2004 MACCS2, Gap Analysis - May 3, 2004 Technical Standards, MACCS2, Gap Analysis - May 3, 2004 May 3, 2004 Software Quality Assurance Improvement Plan: MACCS2 Gap Analysis The MACCS2 software, for radiological dispersion and consequence analysis, is one of the codes designated for the toolbox. To determine the actions needed to bring the MACCS2 code into compliance with the SQA qualification criteria, and develop an estimate of the resources required to perform the upgrade, the Implementation Plan has committed to sponsoring a code-specific gap analysis document. Technical Standards, MACCS2, Gap Analysis More Documents & Publications Technical Standards, Guidance on MACCS2 Computer Code - June 30, 2004 Technical Standards, MELCOR - Gap Analysis - May 3, 2004

484

Exact exchange-potential band-structure calculations by the LMTO-ASA method: MgO and CaO  

Science Journals Connector (OSTI)

We present a method for electronic band-structure calculations based on the density-functional formalism using, instead of the exchange potential in the local-density approximation (LDA), the exact Kohn-Sham density-functional exchange potential. The method is formulated within the linear muffin-tin-orbital method in the atomic-sphere approximation. We apply the method to the alkaline-earth oxides MgO andCaO. The obtained band gaps, 7.77 eV for MgO and 7.72 eV for CaO, are closer to the experimental values of 7.83 and 7.09 eV, respectively, while the corresponding LDA band gaps of 4.64 and 4.30 eV are too small. To our knowledge, the exact exchange potential is first applied to realistic solids. The exact exchange potentials thus calculated show structures well reflecting the atomic shells.

Takao Kotani

1994-11-15T23:59:59.000Z

485

Femtosecond carrier dynamics in Ge measured by a luminescence up-conversion technique and near-band-edge infrared excitation  

Science Journals Connector (OSTI)

The luminescence at the direct band edge of bulk intrinsic and p-type Ge (p?2×1019 cm-3) samples was measured in a two-wavelength up-conversion experiment with ?=1.25–1.35 ?m excitation and at lattice temperatures 20 and 300 K. The near-band-edge carrier dynamics, measured with 100-fs temporal resolution and at carrier densities of 5×1016–2×1018 cm-3, are dominated by electron-phonon intervalley scattering and electron thermalization. Thermalization governs the initial rise of the luminescence in the first 500 fs and is studied as a function of energy and electron density. With excitation photon energy 100 meV greater than the direct band gap, the thermalization time of electrons was measured to decrease with increasing density as n-0.55±0.1. Degeneracy has a strong influence on the thermalization rate with 50 meV excess energy. The L-electron cooling through the electron-hole interaction, as well as hole screening and degeneracy in p-type Ge, is discussed.

G. Mak and W. W. Rühle

1995-10-15T23:59:59.000Z

486

Benefits of Site-wide NEPA Review | Department of Energy  

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

Benefits of Site-wide NEPA Review Benefits of Site-wide NEPA Review Benefits of Site-wide NEPA Review The purpose of this guidance memorandum is to describe potential benefits of conducting a site-wide NEPA review (environmental impact statement or environmental assessment). I believe that this information will help program and field offices prepare their annual NEPA planning summaries and their overall NEPA compliance strategies. Site-wide reviews can aid the Department of Energy (DOE) in meeting its goals to streamline the NEPA process, to make that process more useful to decision makers and the public, and to reduce the time and cost required to prepare NEPA documents Benefits of Site-wide NEPA Review More Documents & Publications Benefits of Site-wide NEPA National Environmental Policy Act Review (1994)

487

Interconnection-Wide Transmission Planning Initiative: Topic A,  

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

Interconnection-Wide Transmission Planning Initiative: Topic A, Interconnection-Wide Transmission Planning Initiative: Topic A, Interconnection-Level Analysis and Planning Interconnection-Wide Transmission Planning Initiative: Topic A, Interconnection-Level Analysis and Planning A description of the requirements for Topic A for all Interconnections under the Interconnection-Wide Transmission Planning Initiative, part of the American Recovery and Reinvestment Act. Interconnection-Wide Transmission Planning Initiative: Topic A, Interconnection-Level Analysis and Planning More Documents & Publications Microsoft Word - yDE-FOA-0000068.rtf Interconnection-Wide Transmission Planning Initiative: Topic B, Cooperation Among States in the Eastern Interconnection on Electric Resource Planning and Priorities Interconnection-Wide Transmission Planning Initiative: Topic B, Cooperation

488

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

489

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

490

Band excitation method applicable to scanning probe microscopy  

DOE Patents [OSTI]

Methods and apparatus are described for scanning probe microscopy. A method