WorldWideScience

Sample records for state band energies

  1. Joint density of states of wide-band-gap materials by electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Fan, X.D.; Peng, J.L.; Bursill, L.A.

    1998-01-01

    Kramers-Kronig analysis for parallel electron energy loss spectroscopy (PEELS) data is developed as a software package. When used with a JEOL 4000EX high-resolution transmission electron microscope (HRTEM) operating at 100 keV this allows us to obtain the dielectric function of relatively wide band gap materials with an energy resolution of approx 1.4 eV. The imaginary part of the dielectric function allows the magnitude of the band gap to be determined as well as the joint-density-of-states function. Routines for obtaining three variations of the joint-density of states function, which may be used to predict the optical and dielectric response for angle-resolved or angle-integration scattering geometries are also described. Applications are presented for diamond, aluminum nitride (AlN), quartz (SiO 2 ) and sapphire (Al 2 O 3 ). The results are compared with values of the band gap and density of states results for these materials obtained with other techniques. (authors)

  2. Validity of single term energy expression for ground state rotational band of even-even nuclei

    International Nuclear Information System (INIS)

    Sharma, S.; Kumar, R.; Gupta, J.B.

    2005-01-01

    Full text: There are large numbers of empirical studies of gs band of even-even nuclei in various mass regions. The Bohr-Mottelson's energy expression is E(I) = AX + BX 2 +CX 3 +... where X = I(I+1). The anharmonic vibrator energy expression is: E(I) = al + bl 2 + cl 3 SF model with energy expression: E(I)= pX + qI + rXI... where the terms represents the rotational, vibrational and R-V interaction energy, respectively. The validity f the various energy expressions with two terms had been tested by Sharma for light, medium and heavy mass regions using R I s. R 4 plots (where, spin I=6, 8, 10, 12), which are parameter independent. It was also noted, that of the goodness of energy expression can be judged with the minimum input of energies (i.e. only 2 parameters) and predictability's of the model p to high spins. Recently, Gupta et. al proposed a single term energy expression (SSTE) which was applied for rare earth region. This proposed power law reflected the unity of rotation - vibration in a different way and was successful in explaining the structure of gs-band. It will be useful for test the single term energy expression for light and heavy mass region. The single term expression for energy of ground state band can be written as: E I =axI b , where the index b and the coefficient a are the constant for the band. The values of b+1 and a 1 are as follows: b 1 =log(R 1 )/log(I/2) and a 1 =E I /I b ... The following results were gained: 1) The sharp variation in the value of index b at given spin will be an indication of the change in the shape of the nucleus; 2) The value of E I /I b is fairly constant with spin below back-bending, which reflects the stability of shape with spin; 3) This proposed power law is successful in explaining the structure of gs-band of nuclei

  3. Role of Electronic Structure In Ion Band State Theory of Low Energy Nuclear Reactions

    Science.gov (United States)

    Chubb, Scott

    2004-03-01

    The Nuts and Bolts of our Ion Band State (IBS) theory of low energy nuclear reactions (LENR's) in palladium-deuteride (PdD) and palladium-hydride (PdH) are the electrons that hold together or tear apart the bonds (or lack of bonds) between deuterons (d's) or protons (p's) and the host material. In PdDx and PdH_x, this bonding is strongly correlated with loading: in ambient loading conditions (x< 0. 6), the bonding in hibits IBS occupation. As x arrow 1, slight increases and decreases in loading can lead to vibrations (which have conventionally been thought to occur from phonons) that can induce potential losses or increases of p/d. Naive assumptions about phonons fail to include these losses and increases. These effects can occur because neither H or D has core electrons and because in either PdD or PdH, the electrons near the Fermi Energy have negligible overlap with the nucleus of either D or H. I use these ideas to develop a formal justification, based on a generalization of conventional band theory (Scott Chubb, "Semi-Classical Conduction of Charged and Neutral Particles in Finite Lattices," 2004 March Meeting."), for the idea that occupation of IBS's can occur and that this can lead to nuclear reactions.

  4. Energies of rare-earth ion states relative to host bands in optical materials from electron photoemission spectroscopy

    Science.gov (United States)

    Thiel, Charles Warren

    There are a vast number of applications for rare-earth-activated materials and much of today's cutting-edge optical technology and emerging innovations are enabled by their unique properties. In many of these applications, interactions between the rare-earth ion and the host material's electronic states can enhance or inhibit performance and provide mechanisms for manipulating the optical properties. Continued advances in these technologies require knowledge of the relative energies of rare-earth and crystal band states so that properties of available materials may be fully understood and new materials may be logically developed. Conventional and resonant electron photoemission techniques were used to measure 4f electron and valence band binding energies in important optical materials, including YAG, YAlO3, and LiYF4. The photoemission spectra were theoretically modeled and analyzed to accurately determine relative energies. By combining these energies with ultraviolet spectroscopy, binding energies of excited 4fN-15d and 4fN+1 states were determined. While the 4fN ground-state energies vary considerably between different trivalent ions and lie near or below the top of the valence band in optical materials, the lowest 4f N-15d states have similar energies and are near the bottom of the conduction band. As an example for YAG, the Tb3+ 4f N ground state is in the band gap at 0.7 eV above the valence band while the Lu3+ ground state is 4.7 eV below the valence band maximum; however, the lowest 4fN-15d states are 2.2 eV below the conduction band for both ions. We found that a simple model accurately describes the binding energies of the 4fN, 4fN-1 5d, and 4fN+1 states. The model's success across the entire rare-earth series indicates that measurements on two different ions in a host are sufficient to predict the energies of all rare-earth ions in that host. This information provides new insight into electron transfer transitions, luminescence quenching, and valence

  5. Band gap and defect states of MgO thin films investigated using reflection electron energy loss spectroscopy

    Directory of Open Access Journals (Sweden)

    Sung Heo

    2015-07-01

    Full Text Available The band gap and defect states of MgO thin films were investigated by using reflection electron energy loss spectroscopy (REELS and high-energy resolution REELS (HR-REELS. HR-REELS with a primary electron energy of 0.3 keV revealed that the surface F center (FS energy was located at approximately 4.2 eV above the valence band maximum (VBM and the surface band gap width (EgS was approximately 6.3 eV. The bulk F center (FB energy was located approximately 4.9 eV above the VBM and the bulk band gap width was about 7.8 eV, when measured by REELS with 3 keV primary electrons. From a first-principles calculation, we confirmed that the 4.2 eV and 4.9 eV peaks were FS and FB, induced by oxygen vacancies. We also experimentally demonstrated that the HR-REELS peak height increases with increasing number of oxygen vacancies. Finally, we calculated the secondary electron emission yields (γ for various noble gases. He and Ne were not influenced by the defect states owing to their higher ionization energies, but Ar, Kr, and Xe exhibited a stronger dependence on the defect states owing to their small ionization energies.

  6. Direct imaging of band profile in single layer MoS2 on graphite: quasiparticle energy gap, metallic edge states, and edge band bending.

    Science.gov (United States)

    Zhang, Chendong; Johnson, Amber; Hsu, Chang-Lung; Li, Lain-Jong; Shih, Chih-Kang

    2014-05-14

    Using scanning tunneling microscopy and spectroscopy, we probe the electronic structures of single layer MoS2 on graphite. The apparent quasiparticle energy gap of single layer MoS2 is measured to be 2.15 ± 0.06 eV at 77 K, albeit a higher second conduction band threshold at 0.2 eV above the apparent conduction band minimum is also observed. Combining it with photoluminescence studies, we deduce an exciton binding energy of 0.22 ± 0.1 eV (or 0.42 eV if the second threshold is use), a value that is lower than current theoretical predictions. Consistent with theoretical predictions, we directly observe metallic edge states of single layer MoS2. In the bulk region of MoS2, the Fermi level is located at 1.8 eV above the valence band maximum, possibly due to the formation of a graphite/MoS2 heterojunction. At the edge, however, we observe an upward band bending of 0.6 eV within a short depletion length of about 5 nm, analogous to the phenomena of Fermi level pinning of a 3D semiconductor by metallic surface states.

  7. The dependence of the tunneling characteristic on the electronic energy bands and the carrier’s states of Graphene superlattice

    Science.gov (United States)

    Yang, C. H.; Shen, G. Z.; Ao, Z. M.; Xu, Y. W.

    2016-09-01

    Using the transfer matrix method, the carrier tunneling properties in graphene superlattice generated by the Thue-Morse sequence and Kolakoski sequence are investigated. The positions and strength of the transmission can be modulated by the barrier structures, the incident energy and angle, the height and width of the potential. These carriers tunneling characteristic can be understood from the energy band structures in the corresponding superlattice systems and the carrier’s states in well/barriers. The transmission peaks above the critical incident angle rely on the carrier’s resonance in the well regions. The structural diversity can modulate the electronic and transport properties, thus expanding its applications.

  8. Influence of linear-energy-dependent density of states on two-band superconductors: Three-square-well model approach

    International Nuclear Information System (INIS)

    Ogbuu, O.A.; Abah, O.C.; Asomba, G.C.; Okoye, C.M.I.

    2011-01-01

    We derived the transition temperature and the isotope exponent of two-band superconductor. We employed Bogoliubov-Valatin formalism assuming a three-square-well potential. The effect of linear-energy-dependent electronic DOS in superconductors is considered. The relevance of the studies to MgB 2 is analyzed. We have derived the expressions for the transition temperature and the isotope effect exponent within the framework of Bogoliubov-Valatin two-band formalism using a linear-energy-dependent electronic density of states assuming a three-square-well potentials model. Our results show that the approach could be used to account for a wide range of values of the transition temperature and isotope effect exponent. The relevance of the present calculations to MgB 2 is analyzed.

  9. Energy correlations for mixed rotational bands

    International Nuclear Information System (INIS)

    Doessing, T.

    1985-01-01

    A schematic model for the mixing of rotational bands above the yrast line in well deformed nuclei is considered. Many-particle configurations of a rotating mean field form basis bands, and these are subsequently mixed due to a two body residual interaction. The energy interval over which a basis band is spread out increases with increasing excitation energy above the yrast line. Conversely, the B(E2) matrix element for rotational decay out of one of the mixed band states is spread over an interval which is predicted to become more narrow with increasing excitation energy. Finally, the implication of band mixing for γ-ray energy correlations is briefly discussed. (orig.)

  10. Study on ground state energy band of even 114-124Cd isotopes under the framework of interacting boson model (IBM-1)

    International Nuclear Information System (INIS)

    Hossain, I.; Abdullah, Hewa Y.; Ahmed, I.M.; Saeed, M.A.; Ahmad, S.T.

    2012-01-01

    In this research, the ground state gamma ray bands of even 114-124 Cd isotopes are calculated using interacting boson model (IBM-1). The theoretical energy levels for Z = 48, N = 66–76 up to spin-parity 8 + have been obtained by using PHINT computer program. The values of the parameters in the IBM-1 Hamiltonian yield the best fit to the experimental energy spectrum. The calculated results of the ground state energy band are compared to the previous experimental results and the obtained theoretical calculations in IBM-1 are in good agreement with the experimental energy level. (author)

  11. Edge states of a periodic chain with four-band energy spectrum

    International Nuclear Information System (INIS)

    Eliashvili, Merab; Kereselidze, Davit; Tsitsishvili, George; Tsitsishvili, Mikheil

    2017-01-01

    Tight-binding model on a finite chain is studied with four-fold alternated hopping parameters t_1_,_2_,_3_,_4. Imposing the open boundary conditions, the corresponding recursion is solved analytically with special attention paid to the occurrence of edge states. Corresponding results are strongly corroborated by numeric calculations. It is shown that in the system there exist four different edge phases if the number of sites is odd, and eight edges phases if the chain comprises even number of sites. Phases are labelled by σ_1 ≡ sgn(t_1t_3 − t_2t_4), σ_2 ≡ sgn(t_1t_4 − t_2t_3), and σ_3 ≡ sgn(t_1t_2 − t_3t_4). It is shown that σ_1_,_2_,_3 represent gauge invariant topological indices emerging in the corresponding infinite chains. (author)

  12. High-energy band structure of gold

    DEFF Research Database (Denmark)

    Christensen, N. Egede

    1976-01-01

    The band structure of gold for energies far above the Fermi level has been calculated using the relativistic augmented-plane-wave method. The calculated f-band edge (Γ6-) lies 15.6 eV above the Fermi level is agreement with recent photoemission work. The band model is applied to interpret...

  13. Solid State KA-Band, Solid State W-Band and TWT Amplifiers, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Phase I of the proposal describes plans to develop a state of the art transmitter for the W-Band and KA -Band Cloud Radar system. Our focus will be concentrated in...

  14. Hole energy and momentum distributions in valence bands

    International Nuclear Information System (INIS)

    Laan, G. van der.

    1982-01-01

    In order to understand the electrical and magnetic properties of solids, the knowledge of the density of states and the dispersion relation of the valence bands is indispensable. This thesis offers some alternative methods to obtain information about the nature of the valence band. Part A deals with the energy distribution of the photoelectrons. A simple model, which explains the core hole satellite structure in compounds with large correlation effects between the valence band holes and the created photo-hole, is outlined. CuCl, CuX 2 (X = F Cl and Br) are studied, by photoemission and Auger electron spectroscopies in determining the valence band properties. Part B deals with the simultaneous measurement of the energy and the wave vector of the emitted electrons. A practical example is given for the determination of the dispersion relation in copper. The measurements of a surface resonance band and the distribution of the secondary electrons are also reported. (Auth.)

  15. Collective states in 230Th: band structure

    Directory of Open Access Journals (Sweden)

    A. I. Levon

    2009-12-01

    Full Text Available Experimental data for the excited states in the deformed nucleus 230Th studied in the (p, t reaction are analyzed. Sequences of the states are selected which can be treated as rotational bands and as multiplets of excitations. Experimental data are compared with the interacting boson model (IBM and the quasiparticle-phonon model (QPM calculations.

  16. Energy bands and gaps near an impurity

    Czech Academy of Sciences Publication Activity Database

    Mihóková, Eva; Schulman, L. S.

    2016-01-01

    Roč. 380, č. 41 (2016), s. 3430-3433 ISSN 0375-9601 R&D Projects: GA ČR GA13-09876S Institutional support: RVO:68378271 Keywords : crystal structure * impurity * modeling * energy bands Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.772, year: 2016

  17. Band mapping of surface states vs. adsorbate coverage

    International Nuclear Information System (INIS)

    Rotenberg, E.; Kevan, S.D.; Denlinger, J.D.; Chung, Jin-Wook

    1997-01-01

    The theory of electron bands, which arises from basic quantum mechanical principles, has been the cornerstone of solid state physics for over 60 years. Simply put, an energy band is an electron state in a solid whose energy varies with its momentum (similar to, but with a more complicated dependence than, how a free electron's energy is proportional to its momentum squared). Much attention over the last 15 years has been given to the study of band structure of surfaces and interfaces, especially as the applications of these two-dimensional systems have become increasingly important to industry and science. The ultraESCA endstation at beamline 7.01 at the Advanced Light Source was developed for very high-energy - (∼50 meV) and angular - ( 12 photons/sec) makes the detailed study of the evolution of bands possible. The authors are interested in learning how, when one forms a chemical bond between a metal and an overlaying atom or molecule, the resulting charge transfer to or from the adsorbate affects the surface bands. In some cases of interest, intermediate coverages lead to different band structure than at the extremes of clean and saturated surfaces. Surfaces of tungsten are particularly interesting, as their atomic geometry has been shown to be exquisitely sensitive to both the surface vibrational and electronic properties. In this study, the authors looked at the surface bands of tungsten ((110) surface), as a function both of coverage and mass of overlaying atoms. The adsorbed atoms were hydrogen and the alkali atoms lithium and cesium

  18. Calculation of the band gap energy of ionic crystals

    International Nuclear Information System (INIS)

    Aguado, A.; Lopez, J.M.; Alonso, J.A.; Ayuela, A.; Rivas S, J.F.; Berrondo, M.

    1998-01-01

    The band gap of alkali halides, alkaline-earth oxides, Al 2 O 3 and SiO 2 crystals has been calculated using the perturbed-ion model supplemented with some assumptions for the treatment of excited states. The gap is calculated in several ways: as a difference between one-electron energy eigenvalues and as a difference between the total energies of appropriate electronic states of the crystal, both at the HF level and with inclusion of Coulomb correlation effects. The results compare well with experimental band gap energies and with other theoretical calculations, suggesting that the picture of bonding and excitation given by the model can be useful in ionic materials. (Author)

  19. Nuts and Bolts of the Ion Band State Theory

    Science.gov (United States)

    Chubb, Scott R.

    2005-12-01

    The nuts and bolts of our ion band state theory of low energy nuclear reactions (LENR's) in palladium-deuteride (PdD) and palladium-hydride (PdH) are the electrons that hold together or tear apart the bonds (or lack of bonds) between deuterons (d's) or protons (p's) and the host material. In PdDx and PdHx, this bonding is strongly correlated with loading. In ambient loading conditions (x ≲ 0.6), bonding inhibits ion band state occupation. As x → 1, slight increases and decreases in loading can induce "vibrations" (which have conventionally been thought to occur from phonons) that can induce potential losses or increases of p/d. Naive assumptions about phonons fail to include these losses and increases. These effects can occur because neither H or D has core electrons and because in either PdD or PdH, the electrons near the Fermi energy have negligible overlap with the nucleus of either D or H. In the past, implicitly, we have used these facts to justify our ion band state theory. Here, we present a more formal justification, based on the relationship between H(D) ion band states (IBS's) and H(D) phonons that includes a microscopic picture that explains why occupation of IBS's can occur in PdD and PdH and how this can lead to nuclear reactions.

  20. Topological nanophononic states by band inversion

    Science.gov (United States)

    Esmann, Martin; Lamberti, Fabrice Roland; Senellart, Pascale; Favero, Ivan; Krebs, Olivier; Lanco, Loïc; Gomez Carbonell, Carmen; Lemaître, Aristide; Lanzillotti-Kimura, Norberto Daniel

    2018-04-01

    Nanophononics is essential for the engineering of thermal transport in nanostructured electronic devices, it greatly facilitates the manipulation of mechanical resonators in the quantum regime, and it could unveil a new route in quantum communications using phonons as carriers of information. Acoustic phonons also constitute a versatile platform for the study of fundamental wave dynamics, including Bloch oscillations, Wannier-Stark ladders, and other localization phenomena. Many of the phenomena studied in nanophononics were inspired by their counterparts in optics and electronics. In these fields, the consideration of topological invariants to control wave dynamics has already had a great impact for the generation of robust confined states. Interestingly, the use of topological phases to engineer nanophononic devices remains an unexplored and promising field. Conversely, the use of acoustic phonons could constitute a rich platform to study topological states. Here, we introduce the concept of topological invariants to nanophononics and experimentally implement a nanophononic system supporting a robust topological interface state at 350 GHz. The state is constructed through band inversion, i.e., by concatenating two semiconductor superlattices with inverted spatial mode symmetries. The existence of this state is purely determined by the Zak phases of the constituent superlattices, i.e., the one-dimensional Berry phase. We experimentally evidenced the mode through Raman spectroscopy. The reported robust topological interface states could become part of nanophononic devices requiring resonant structures such as sensors or phonon lasers.

  1. Weyl states and Fermi arcs in parabolic bands

    Science.gov (United States)

    Doria, Mauro M.; Perali, Andrea

    2017-07-01

    Weyl fermions are shown to exist inside a parabolic band in a single electronic layer, where the kinetic energy of carriers is given by the non-relativistic Schroedinger equation. There are Fermi arcs as a direct consequence of the folding of a ring-shaped Fermi surface inside the first Brillouin zone. Our results stem from the decomposition of the kinetic energy into the sum of the square of the Weyl state, the coupling to the local magnetic field and the Rashba interaction. The Weyl fermions break the space and time reflection symmetries present in the kinetic energy, thus allowing for the onset of a weak three-dimensional magnetic field around the layer. This field brings topological stability to the current-carrying states through a Chern number. In the special limit for which the Weyl state becomes gapless, this magnetic interaction is shown to be purely attractive, thus suggesting the onset of a superconducting condensate of zero helicity states.

  2. Energies of conduction bands in dielectric liquids

    International Nuclear Information System (INIS)

    Holroyd, R.

    1975-01-01

    The properties of excess electrons in non-polar liquids depend on the relative energies of the trapped and conducting states. We have measured the energies of the conducting states, denoted V 0 , for about twenty non-polar liquids. Two methods were used: In one the work functions of metals immersed in the liquid were measured. In the other, solutes (TMPD) were photoionized in the liquid and V 0 calculated from the wavelength at which ionization onsets occur. A wide variation in conduction state energies is observed from a high of +0.21 eV for tetradecane to a low of --0.60 eV for tetramethylsilane. In general V 0 shifts to more negative values with increasing molecular symmetry, and correlates well with electron mobility. The photoionization results indicate that V 0 decreases with increasing temperature. In mixtures V 0 is linearly dependent on mole fraction. It was found empirically for n-hexane-neopentane mixtures that μ = 0.34 exp [--15.2(V 0 )]. This equation relating V 0 to the electron mobility also applies approximately to pure hydrocarbons. Thus the role of the conduction state energy in influencing electron mobilities and photoionization onsets is established and recent evidence indicates V 0 also influences the rates of electron reactions in these liquids

  3. Current state of X-band accelerating structure high gradient test. Be held at high energy accelerator organization on April 15, 2005

    International Nuclear Information System (INIS)

    Watanabe, Ken; Higo, Toshiyasu

    2005-01-01

    XTF (X-band Test Facility, Old name is GLCTA) is the high gradient test facility for X-band acceleration. We have installed an X-band 60cm structure (KX01) in the April 2004 and have been processing it for more than 10 months. Now it is under test on long-term operation. We report here the high gradient test result to date. (author)

  4. Conservation of topological quantum numbers in energy bands

    International Nuclear Information System (INIS)

    Chang, L.N.; Liang, Y.

    1988-01-01

    Quantum systems described by parametrized Hamiltinians are studied in a general context. Within this context, the classification scheme of Avron-Seiler-Simon for non-degenerate energy bands is extended to cover general parameter spaces, whole their sum rule is generalized to cover cases with degenerate bands as well. Additive topological quantum numbers are defined, and these are shown to be conserved in energy band ''collisions''. The conservation laws dictate that when some invariants are non-vanishing, no energy gap can develop in a set of degenerate bands. This gives rise to a series of splitting rules

  5. High resolution spectral analysis of oxygen. IV. Energy levels, partition sums, band constants, RKR potentials, Franck-Condon factors involving the X3Σg−, a1Δg and b1Σg+ states

    International Nuclear Information System (INIS)

    Yu, Shanshan; Drouin, Brian J.; Miller, Charles E.

    2014-01-01

    We have updated the isotopically invariant Dunham fit of O 2 with newly reported literature transitions to derive (1) the energy levels, partition sums, band-by-band molecular constants, and RKR potentials for the X 3 Σ g − , a 1 Δ g , and b 1 Σ g + states of the six O 2 isotopologues: 16 O 16 O, 16 O 17 O, 16 O 18 O, 17 O 17 O, 17 O 18 O, and 18 O 18 O; (2) Franck-Condon factors for their a 1 Δ g −X 3 Σ g − , b 1 Σ g + −X 3 Σ g − , and a 1 Δ g −b 1 Σ g + band systems. This new spectroscopic parameterization characterizes all known transitions within and between the X 3 Σ g − , a 1 Δ g , and b 1 Σ g + states within experimental uncertainty and can be used for accurate predictions of as yet unmeasured transitions. All of these results are necessary to provide a consistent linelist of all transitions which will be reported in a followup paper

  6. Interpolation of band-limited discrete-time signals by minimising out-of-band energy

    NARCIS (Netherlands)

    Janssen, A.J.E.M.; Vries, L.B.

    1984-01-01

    An interpolation method for restoring burst errors in discrete—time, band—limited signals is presented. The restoration is such that the restored signal has minimal out—of—band energy. The filter coefficients depend Only on the burst length and on the size of the band to which the signal is assumed

  7. Quantitative analysis on electric dipole energy in Rashba band splitting.

    Science.gov (United States)

    Hong, Jisook; Rhim, Jun-Won; Kim, Changyoung; Ryong Park, Seung; Hoon Shim, Ji

    2015-09-01

    We report on quantitative comparison between the electric dipole energy and the Rashba band splitting in model systems of Bi and Sb triangular monolayers under a perpendicular electric field. We used both first-principles and tight binding calculations on p-orbitals with spin-orbit coupling. First-principles calculation shows Rashba band splitting in both systems. It also shows asymmetric charge distributions in the Rashba split bands which are induced by the orbital angular momentum. We calculated the electric dipole energies from coupling of the asymmetric charge distribution and external electric field, and compared it to the Rashba splitting. Remarkably, the total split energy is found to come mostly from the difference in the electric dipole energy for both Bi and Sb systems. A perturbative approach for long wave length limit starting from tight binding calculation also supports that the Rashba band splitting originates mostly from the electric dipole energy difference in the strong atomic spin-orbit coupling regime.

  8. Ground state shape and crossing of near spherical and deformed bands in 182Hg

    International Nuclear Information System (INIS)

    Ma, W.C.; Ramayya, A.V.; Hamilton, J.H.; Robinson, S.J.; Barclay, M.E.; Zhao, K.; Cole, J.D.; Zganjar, E.F.; Spejewski, E.H.

    1983-01-01

    The energy levels of 182 Hg have been identified for the first time through comparison of in-beam studies of the reactions 156 154 Gd( 32 S,4n) 184 182 Hg. Levels up to 12 + in 182 Hg were established from γ-γ coincidence and singles measurement. The data establish that the ground state shape is near spherical, and that the ground band is crossed by a well deformed band at 4 + . In contrast to IBA model predictions that the deformed band will rise in energy in 182 Hg compared to 184 Hg, the energies of the deformed levels in 182 Hg continue to drop. 7 references

  9. Stability of the split-band solution and energy gap in the narrow-band region of the Hubbard model

    International Nuclear Information System (INIS)

    Arai, T.; Cohen, M.H.

    1980-01-01

    By inserting quasielectron energies ω calculated from the fully renormalized Green's function of the Hubbard model obtained in the preceding paper into the exact expression of Galitskii and Migdal, the ground-state energy, the chemical potential, and the dynamic- and thermodynamic-stability conditions are calculated in the narrow-band region. The results show that as long as the interaction energy I is finite, electrons in the narrow-band region do not obey the Landau theory of Fermi liquids, and a gap appears between the lowest quasielectron energy ω and the chemical potential μ for any occupation n, regardless of whether the lower band is exactly filled or not. This unusual behavior is possible because, when an electron is added to the system of N electrons, the whole system relaxes due to the strong interaction, introducing a relaxation energy difference between the two quantities. We also show that all previous solutions which exhibit the split-band structure, including Hubbard's work, yield the same conclusion that electrons do not behave like Landau quasiparticles. However, the energy gap is calculated to be negative at least for some occupations n, demonstrating the dynamic instability of those solutions. They also exhibit thermodynamic instability for certain occupations, while the fully renormalized solution, having sufficient electron correlations built in, satisfies the dynamic and thermodynamic stability conditions for all occupations. When the lower band is nearly filled, the nature of the solution is shown to change, making the coherent motion of electrons with fixed k values more difficult. In the pathological limit where I=infinity, however, the gap vanishes, yielding a metallic state

  10. Magnetron based high energy S-band linac system

    International Nuclear Information System (INIS)

    Tiwari, T.; Krishnan, R.; Phatangare, Manoj

    2012-01-01

    This paper deals with the study of magnetron based high energy S-band linear accelerator (linac) system operating at spot frequency 2.998 GHz. The energy and dose are two important parameters of linac system which depend on input power of microwave source and length of linac tube. Here the author has studied how these parameters can be improved for side coupled standing wave S-band linac system

  11. Energy band dispersion in photoemission spectra of argon clusters

    International Nuclear Information System (INIS)

    Foerstel, Marko; Mucke, Melanie; Arion, Tiberiu; Lischke, Toralf; Barth, Silko; Ulrich, Volker; Ohrwall, Gunnar; Bjoerneholm, Olle; Hergenhahn, Uwe; Bradshaw, Alex M.

    2011-01-01

    Using photoemission we have investigated free argon clusters from a supersonic nozzle expansion in the photon energy range from threshold up to 28 eV. Measurements were performed both at high resolution with a hemispherical electrostatic energy analyser and at lower resolution with a magnetic bottle device. The latter experiments were performed for various mean cluster sizes. In addition to the ∼1.5 eV broad 3p-derived valence band seen in previous work, there is a sharper feature at ∼15 eV binding energy. Surprisingly for non-oriented clusters, this peak shifts smoothly in binding energy over the narrow photon energy range 15.5-17.7 eV, indicating energy band dispersion. The onset of this bulk band-like behaviour could be determined from the cluster size dependence.

  12. Determination of density of band-gap states of hydrogenated amorphous silicon suboxide thin films

    International Nuclear Information System (INIS)

    Bacioglu, A.

    2005-01-01

    Variation of density of gap states of PECVD silicon suboxide films with different oxygen concentrations was evaluated through electrical and optical measurements. Optical transmission and constant photocurrent method (CPM) were used to determine absorption coefficient as a function of photon energy. From these measurements the localized density of states between the valance band mobility edge and Fermi level has been determined. To determine the variation of conduction band edge, steady state photoconductivity (SSPC), photoconductivity response time (PCRT) and transient photoconductivity (TPC) measurements were utilized. Results indicate that the conduction and valance band edges, both, widen monotonically with oxygen content

  13. State Energy Resilience Framework

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Finster, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Pillon, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Petit, F. [Argonne National Lab. (ANL), Argonne, IL (United States); Trail, J. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-12-01

    The energy sector infrastructure’s high degree of interconnectedness with other critical infrastructure systems can lead to cascading and escalating failures that can strongly affect both economic and social activities.The operational goal is to maintain energy availability for customers and consumers. For this body of work, a State Energy Resilience Framework in five steps is proposed.

  14. Fermi integral and density-of-states functions in a parabolic band ...

    Indian Academy of Sciences (India)

    B K Chaudhuri

    2018-01-03

    Jan 3, 2018 ... distribution of the potential energy of the impurity states, showing a band tail in them e.g., ... oscillatory function of η (reduced Fermi energy = Ef/kBT, kB is the Boltzmann ...... grals, in: Network for computational nanotechnology.

  15. State-to-state photodissociation dynamics of triatomic molecules: H2O in the B band

    International Nuclear Information System (INIS)

    Jiang Bin; Xie Daiqian; Guo Hua

    2012-01-01

    State-to-state photodissociation dynamics of H 2 O in its B band has been investigated quantum mechanically on a new set of non-adiabatically coupled potential energy surfaces for the lowest two 1 A' states of H 2 O, which are developed at the internally contracted multi-reference configuration interaction level with the aug-cc-pVQZ basis set. Quantum dynamical calculations carried out using the Chebyshev propagator yield absorption spectra, product state distributions, branching ratios, and differential cross sections, which are in reasonably good agreement with the latest experimental results. Particular focus is placed here on the dependence of various dynamical observables on the photon energy. Detailed analyses of the dynamics have assigned the diffuse structure in absorption spectrum to short-time recurring dynamics near the HOH conical intersection. The non-adiabatic dissociation to the ground state OH product via the HOH conical intersection is facile, direct, fast, and produces rotationally hot OH(X-tilde) products. On the other hand, the adiabatic channel on the excited state leading to the OH(A-tilde) product is dominated by long-lived resonances, which depend sensitively on the potential energy surfaces.

  16. Experimental study of energy harvesting in UHF band

    International Nuclear Information System (INIS)

    Bernacki, Ł; Gozdur, R; Salamon, N

    2016-01-01

    A huge progress of down-sizing technology together with trend of decreasing power consumption and, on the other hand, increasing efficiency of electronics give the opportunity to design and to implement the energy harvesters as main power sources. This paper refers to the energy that can be harvested from electromagnetic field in the unlicensed frequency bands. The paper contains description of the most popular techniques and transducers that can be applied in energy harvesting domain. The overview of current research and commercial solutions was performed for bands in ultra-high frequency range, which are unlicensed and where transmission is not limited by administrative arrangements. During the experiments with Powercast’s receiver, the same bands as sources of electromagnetic field were taken into account. This power source is used for conducting radio-communication process and excess energy could be used for powering the extra electronic circuits. The paper presents elaborated prototype of energy harvesting system and the measurements of power harvested in ultra-high frequency range. The evaluation of RF energy harvesters for powering ultra-low power (ULP) electronic devices was performed based on survey and results of the experiments. (paper)

  17. Dirac Cones, Topological Edge States, and Nontrivial Flat Bands in Two-Dimensional Semiconductors with a Honeycomb Nanogeometry

    Directory of Open Access Journals (Sweden)

    E. Kalesaki

    2014-01-01

    Full Text Available We study theoretically two-dimensional single-crystalline sheets of semiconductors that form a honeycomb lattice with a period below 10 nm. These systems could combine the usual semiconductor properties with Dirac bands. Using atomistic tight-binding calculations, we show that both the atomic lattice and the overall geometry influence the band structure, revealing materials with unusual electronic properties. In rocksalt Pb chalcogenides, the expected Dirac-type features are clouded by a complex band structure. However, in the case of zinc-blende Cd-chalcogenide semiconductors, the honeycomb nanogeometry leads to rich band structures, including, in the conduction band, Dirac cones at two distinct energies and nontrivial flat bands and, in the valence band, topological edge states. These edge states are present in several electronic gaps opened in the valence band by the spin-orbit coupling and the quantum confinement in the honeycomb geometry. The lowest Dirac conduction band has S-orbital character and is equivalent to the π-π^{⋆} band of graphene but with renormalized couplings. The conduction bands higher in energy have no counterpart in graphene; they combine a Dirac cone and flat bands because of their P-orbital character. We show that the width of the Dirac bands varies between tens and hundreds of meV. These systems emerge as remarkable platforms for studying complex electronic phases starting from conventional semiconductors. Recent advancements in colloidal chemistry indicate that these materials can be synthesized from semiconductor nanocrystals.

  18. Nontrivial topological states on a Möbius band

    NARCIS (Netherlands)

    Beugeling, W.; Quelle, A.; Morais Smith, C.

    2014-01-01

    In the field of topological insulators, the topological properties of quantum states in samples with simple geometries, such as a cylinder or a ribbon, have been classified and understood during the past decade. Here we extend these studies to a Möbius band and argue that its lack of orientability

  19. Satellite bands of the RbCs molecule in the range of highly excited states

    Energy Technology Data Exchange (ETDEWEB)

    Rakić, Mario; Beuc, Robert; Skenderović, Hrvoje, E-mail: hrvoje@ifs.hr [Institute of Physics, Bijenička cesta 46, Zagreb 10000 (Croatia); Bouloufa-Maafa, Nadia; Dulieu, Olivier; Vexiau, Romain [Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, Bât. 505, Campus d’Orsay, Orsay Cedex 91405 (France); Pichler, Goran [Physics Department, Kuwait University, PO Box 5969, Safat—13060 (Kuwait)

    2016-05-28

    We report on the observation of three RbCs satellite bands in the blue and green ranges of the visible spectrum. Absorption measurements are performed using all-sapphire cell filled with a mixture of Rb and Cs. We compare high resolution absorption spectrum of Rb-Cs vapor mixture with pure Rb and Cs vapor spectra from the literature. After detailed analysis, the new satellite bands of RbCs molecule at 418.3 nm, 468.3, and 527.5 nm are identified. The origin of these bands is discussed by direct comparison with difference potentials derived from quantum chemistry calculations of RbCs potential energy curves. These bands originate from the lower Rydberg states of the RbCs molecule. This study thus provides further insight into photoassociation of lower Rydberg molecular states, approximately between Cs(7s) + Rb(5s) and Cs(6s) + Rb(6p) asymptotes, in ultracold gases.

  20. Nature of the valence band states in Bi2(Ca, Sr, La)3Cu2O8

    International Nuclear Information System (INIS)

    Wells, B.O.; Lindberg, P.A.P.; Shen, Z.; Dessau, D.S.; Spicer, W.E.; Lindau, I.; Mitzi, D.B.; Kapitulnik, A.

    1990-01-01

    We have used photoemission spectroscopy to examine the symmetry of the occupied states of the valence band for the La doped superconductor Bi 2 (Ca, Sr, La) 3 Cu 2 O 8 . While the oxygen states near the bottom of the 7 eV wide valence band exhibit predominantly O 2p z symmetry, the states at the top of the valence band extending to the Fermi level are found to have primarily O 2p x and O 2p y character. We have also examined anomalous intensity enhancements in the valence band feature for photon energies near 18 eV. These enhancements, which occur at photon energies ranging from 15.8 to 18.0 eV for the different valence band features, are not consistent with either simple final state effects or direct O2s transitions to unoccupied O2p states

  1. Warm-Up Activities of Middle and High School Band Directors Participating in State-Level Concert Band Assessments

    Science.gov (United States)

    Ward, Justin P.; Hancock, Carl B.

    2016-01-01

    The purpose of this study was to examine the warm-ups chosen by concert band directors participating in state-level performance assessments. We observed 29 middle and high school bands and coded the frequency and duration of warm-up activities and behaviors. Results indicated that most bands rehearsed music and played scales, long tones, and…

  2. Magnetic oscillations and quasiparticle band structure in the mixed state of type-II superconductors

    International Nuclear Information System (INIS)

    Norman, M.R.; MacDonald, A.H.; Akera, H.

    1995-01-01

    We consider magnetic oscillations due to Landau quantization in the mixed state of type-II superconductors. Our work is based on a previously developed formalism which allows the mean-field gap equations of the Abrikosov state to be conveniently solved in a Landau-level representation. We find that the quasiparticle band structure changes qualitatively when the pairing self-energy becomes comparable to the Landau-level separation. For small pairing self-energies, Landau-level mixing due to the superconducting order is weak and magnetic oscillations survive in the superconducting state although they are damped. We find that the width of the quasiparticle Landau levels in this regime varies approximately as Δ 0 n μ -1/4 where Δ 0 is proportional to the magnitude of the order parameter and n μ is the Landau-level index at the Fermi energy. For larger pairing self-energies, the lowest energy quasiparticle bands occur in pairs which are nearly equally spaced from each other and evolve with weakening magnetic field toward the bound states of an isolated vortex core. These bands have a weak magnetic field dependence and magnetic oscillations vanish rapidly in this regime. We discuss recent observations of the de Haas--van Alphen effect in the mixed state of several type-II superconductors in light of our results

  3. Intrinsic states and rotational bands in 177Pt

    International Nuclear Information System (INIS)

    Dracoulis, G.D.; Fabricius, B.; Bark, R.A.; Stuchbery, A.E.; Popescu, D.G.; Kibedi, T.

    1989-11-01

    The 149 Sm ( 32 S,4n) 177 Pt reaction has been used to populate excited states in the neutron-deficient nucleus 177 Pt. Rotational bands based on intrinsic states assigned to the 1/2-[521], 5/2-[521] and (mixed) 7/2+ [633] Nilsson configurations have been observed. In contrast to the neighbou-ring even isotope 176 Pt, anomalies attributed to shape co-existence at low spin have not been observed. Implications for the deformation of 177 Pt are discussed together with the systematics of intrinsic states in this region, and alignments and other properties of N=99 nuclei. 37 refs., 15 figs., 3 tabs

  4. The collective bands of positive parity states in odd-A (fp) shell nuclei

    International Nuclear Information System (INIS)

    Ahalpara, D.P.

    1979-01-01

    The low-lying collective bands of positive parity states in (fp) shell nuclei are described in the deformed Hartree-Fock method by projecting states of definite angular momenta from 'the lowest energy intrinsic states in (sd)sup(-1)(fp)sup(n+1) configurations. The modified Kuo-Brown effective interaction for (fp) shell and modified surface delta interaction (MSDI) for a hole in (sd) shell with a particle in (fp) shell have been used. The collective bands of states are in general well reproduced by the effective interactions. The excitation energies of the band head states are however off by about one MeV. The calculated magnetic moments of the band head j = 3/2 + states are in reasonable agreement with experiment. Using effective charges esub(p) = 1.33 e and esub(n) = 0.64 e fairly good agreement is obtained for E(2) transitions. The hindered M(1) transition strengths are reproduced to the correct order, however they are slightly higher compared to the experiment. (author)

  5. Ground-state and pairing-vibrational bands with equal quadrupole collectivity in 124Xe

    Science.gov (United States)

    Radich, A. J.; Garrett, P. E.; Allmond, J. M.; Andreoiu, C.; Ball, G. C.; Bianco, L.; Bildstein, V.; Chagnon-Lessard, S.; Cross, D. S.; Demand, G. A.; Diaz Varela, A.; Dunlop, R.; Finlay, P.; Garnsworthy, A. B.; Hackman, G.; Hadinia, B.; Jigmeddorj, B.; Laffoley, A. T.; Leach, K. G.; Michetti-Wilson, J.; Orce, J. N.; Rajabali, M. M.; Rand, E. T.; Starosta, K.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Wang, Z. M.; Wood, J. L.; Wong, J.; Williams, S. J.; Yates, S. W.

    2015-04-01

    The nuclear structure of 124Xe has been investigated via measurements of the β+/EC decay of 124Cs with the 8 π γ -ray spectrometer at the TRIUMF-ISAC facility. The data collected have enabled branching ratio measurements of weak, low-energy transitions from highly excited states, and the 2+→0+ in-band transitions have been observed. Combining these results with those from a previous Coulomb excitation study, B (E 2 ;23+→02+) =78 (13 ) W.u. and B (E 2 ;24+→03+) =53 (12 ) W.u. were determined. The 03+ state, in particular, is interpreted as the main fragment of the proton-pairing vibrational band identified in a previous 122Te (3He,n )124Xe measurement, and has quadrupole collectivity equal to, within uncertainty, that of the ground-state band.

  6. Band width and multiple-angle valence-state mapping of diamond

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, I.; Terminello, L.J.; Sutherland, D.G.J. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    The band width may be considered the single most important parameter characterizing the electronic structure of a solid. The ratio of band width and Coulomb repulsion determines how correlated or delocalized an electron system is. Some of the most interesting solids straddle the boundary between localized and delocalized, e.g. the high-temperature superconductors. The bulk of the band calculations available today is based on local density functional (DF) theory. Even though the Kohn-Sham eigenvalues from that theory do not represent the outcome of a band-mapping experiment, they are remarkably similar to the bands mapped via photoemission. Strictly speaking, one should use an excited state calculation that takes the solid`s many-body screening response to the hole created in photoemission into account. Diamond is a useful prototype semiconductor because of its low atomic number and large band width, which has made it a long-time favorite for testing band theory. Yet, the two experimental values of the band width of diamond have error bars of {+-}1 eV and differ by 3.2 eV. To obtain an accurate valence band width for diamond, the authors use a band-mapping method that collects momentum distributions instead of the usual energy distributions. This method has undergone extensive experimental and theoretical tests in determining the band width of lithium fluoride. An efficient, imaging photoelectron spectrometer is coupled with a state-of-the-art undulator beam line at the Advanced Light Source to allow collection of a large number of data sets. Since it takes only a few seconds to take a picture of the photoelectrons emitted into a 84{degrees} cone, the authors can use photon energies as high as 350 eV where the cross section for photoemission from the valence band is already quite low, but the emitted photoelectrons behave free-electron-like. This make its much easier to locate the origin of the inter-band transitions in momentum space.

  7. Band width and multiple-angle valence-state mapping of diamond

    International Nuclear Information System (INIS)

    Jimenez, I.; Terminello, L.J.; Sutherland, D.G.J.

    1997-01-01

    The band width may be considered the single most important parameter characterizing the electronic structure of a solid. The ratio of band width and Coulomb repulsion determines how correlated or delocalized an electron system is. Some of the most interesting solids straddle the boundary between localized and delocalized, e.g. the high-temperature superconductors. The bulk of the band calculations available today is based on local density functional (DF) theory. Even though the Kohn-Sham eigenvalues from that theory do not represent the outcome of a band-mapping experiment, they are remarkably similar to the bands mapped via photoemission. Strictly speaking, one should use an excited state calculation that takes the solid's many-body screening response to the hole created in photoemission into account. Diamond is a useful prototype semiconductor because of its low atomic number and large band width, which has made it a long-time favorite for testing band theory. Yet, the two experimental values of the band width of diamond have error bars of ±1 eV and differ by 3.2 eV. To obtain an accurate valence band width for diamond, the authors use a band-mapping method that collects momentum distributions instead of the usual energy distributions. This method has undergone extensive experimental and theoretical tests in determining the band width of lithium fluoride. An efficient, imaging photoelectron spectrometer is coupled with a state-of-the-art undulator beam line at the Advanced Light Source to allow collection of a large number of data sets. Since it takes only a few seconds to take a picture of the photoelectrons emitted into a 84 degrees cone, the authors can use photon energies as high as 350 eV where the cross section for photoemission from the valence band is already quite low, but the emitted photoelectrons behave free-electron-like. This make its much easier to locate the origin of the inter-band transitions in momentum space

  8. Electron correlations in narrow energy bands: modified polar model approach

    Directory of Open Access Journals (Sweden)

    L. Didukh

    2008-09-01

    Full Text Available The electron correlations in narrow energy bands are examined within the framework of the modified form of polar model. This model permits to analyze the effect of strong Coulomb correlation, inter-atomic exchange and correlated hopping of electrons and explain some peculiarities of the properties of narrow-band materials, namely the metal-insulator transition with an increase of temperature, nonlinear concentration dependence of Curie temperature and peculiarities of transport properties of electronic subsystem. Using a variant of generalized Hartree-Fock approximation, the single-electron Green's function and quasi-particle energy spectrum of the model are calculated. Metal-insulator transition with the change of temperature is investigated in a system with correlated hopping. Processes of ferromagnetic ordering stabilization in the system with various forms of electronic DOS are studied. The static conductivity and effective spin-dependent masses of current carriers are calculated as a function of electron concentration at various DOS forms. The correlated hopping is shown to cause the electron-hole asymmetry of transport and ferromagnetic properties of narrow band materials.

  9. Energy of the 4(+) isomer and new bands in the odd-odd nucleus 74Br

    International Nuclear Information System (INIS)

    Doering, J.; Holcomb, J.W.; Johnson, T.D.; Riley, M.A.; Tabor, S.L.; Womble, P.C.; Winter, G.

    1993-01-01

    High-spin states of the odd-odd nucleus 74 Br were investigated via the reactions 58 Ni ( 19 F,2pn) 74 Br and 65 Cu( 12 C,3n) 74 Br at beam energies of 62 and 50 MeV, respectively. On the basis of coincidence data new levels have been introduced and partly grouped into rotational bands. Some of these new states decay to known levels of negative-parity bands built on both the ground state and the long-lived 4 (+) isomer. Thus, an excitation energy of 13.8 keV has been deduced for the long-lived isomer in 74 Br. The level sequences observed are interpreted in terms of Nilsson configurations in conjunction with collective excitations

  10. Solid-State Powered X-band Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Mohamed A.K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Nann, Emilio A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Dolgashev, Valery A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tantawi, Sami [SLAC National Accelerator Lab., Menlo Park, CA (United States); Neilson, Jeff [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2017-03-06

    In this report we disseminate the hot test results of an X-band 100-W solid state amplifier chain for linear accelerator (linac) applications. Solid state power amplifiers have become increasingly attractive solutions for achieving high power in radar and maritime applications. Here the performance of solid state amplifiers when driving an RF cavity is investigated. Commercially available, matched and fully-packaged GaN on SiC HEMTs are utilized, comprising a wideband driver stage and two power stages. The amplifier chain has a high poweradded- efficiency and is able to supply up to ~1.2 MV/m field gradient at 9.2 GHz in a simple test cavity, with a peak power exceeding 100 W. These findings set forth the enabling technology for solid-state powered linacs.

  11. State Energy Program Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2018-02-01

    The U.S. Department of Energy’s State Energy Program (SEP) provides funding and technical assistance to states, territories, and the District of Columbia to enhance energy security, advance state-led energy initiatives, and maximize the benefits of decreasing energy waste.

  12. CZTS stoichiometry effects on the band gap energy

    International Nuclear Information System (INIS)

    Malerba, Claudia; Biccari, Francesco; Azanza Ricardo, Cristy Leonor; Valentini, Matteo; Chierchia, Rosa; Müller, Melanie; Santoni, Antonino; Esposito, Emilia; Mangiapane, Pietro; Scardi, Paolo; Mittiga, Alberto

    2014-01-01

    Highlights: • CZTS films with different compositions were grown from stacked-layer precursors. • The band-gap energy varies from 1.48 to 1.63 eV as the [Sn]/[Cu] ratio increases. • The Zn content seems not to be a critical parameter for the optical properties. • PDS data show an increase of the sub-gap absorption as the Sn content is reduced. • Formation of defects at low Sn content was proposed to explain the Eg variation. -- Abstract: The considerable spread of Cu 2 ZnSnS 4 (CZTS) optical properties reported in the literature is discussed in terms of material stoichiometry. To this purpose, kesterite thin films were prepared by sulfurization of multilayered precursors of ZnS, Cu and Sn, changing the relative amounts to obtain CZTS layers with different compositions. X-Ray Diffraction (XRD), Energy Dispersive X-Ray (EDX) spectroscopy, X-Ray Photoelectron Spectroscopy (XPS) and Raman spectroscopy were used for structural and compositional analysis. XRD quantitative phase analysis provides the amount of spurious phases and information on Sn-site occupancy. The optical properties were investigated by spectrophotometric and Photothermal Deflection Spectroscopy (PDS) measurements to assess the absorption coefficient of samples with different compositions. The PDS data show an increase of the sub-band absorption as the Sn content decreases. The results are interpreted assuming the formation of additional defects as the tin content is reduced. Those defects can also be responsible for the decrease of the band gap energy value as the Sn/Cu ratio is decreased

  13. State Energy Program Operations Manual

    Energy Technology Data Exchange (ETDEWEB)

    Office of Building Technology, State and Community Programs

    1999-03-17

    The State Energy Program Operations Manual is a reference tool for the states and the program officials at the U.S. Department of Energy's Office of Building Technology, State and Community Programs and Regional Support Offices as well as State Energy Offices. The Manual contains information needed to apply for and administer the State Energy Program, including program history, application rules and requirements, and program administration and monitoring requirements.

  14. Coexistence of spherical states with deformed and superdeformed bands in doubly magic 40Ca; A shell model challenge

    International Nuclear Information System (INIS)

    Caurier, E.; Nowacki, F.; Menendez, J.; Poves, A.

    2007-02-01

    Large scale shell model calculations, with dimensions reaching 10 9 , are carried out to describe the recently observed deformed (ND) and superdeformed (SD) bands based on the first and second excited 0 + states of 40 Ca at 3.35 MeV and 5.21 MeV respectively. A valence space comprising two major oscillator shells, sd and pf, can accommodate most of the relevant degrees of freedom of this problem. The ND band is dominated by configurations with four particles promoted to the pf-shell (4p-4h in short). The SD band by 8p-8h configurations. The ground state of 40 Ca is strongly correlated, but the closed shell still amounts to 65%. The energies of the bands are very well reproduced by the calculations. The out-band transitions connecting the SD band with other states are very small and depend on the details of the mixing among the different np-nh configurations, in spite of that, the calculation describes them reasonably. For the in-band transition probabilities along the SD band, we predict a fairly constant transition quadrupole moment Q 0 (t) ∼ 70 e fm 2 up to J=10, that decreases toward the higher spins. We submit also that the J=8 states of the deformed and superdeformed band are maximally mixed. (authors)

  15. Coexistence of spherical states with deformed and superdeformed bands in doubly magic 40Ca: A shell-model challenge

    International Nuclear Information System (INIS)

    Caurier, E.; Nowacki, F.; Menendez, J.; Poves, A.

    2007-01-01

    Large-scale shell-model calculations, with dimensions reaching 10 9 , are carried out to describe the recently observed deformed (ND) and superdeformed (SD) bands based on the first and second excited 0 + states of 40 Ca at 3.35 and 5.21 MeV, respectively. A valence space comprising two major oscillator shells, sd and pf, can accommodate most of the relevant degrees of freedom of this problem. The ND band is dominated by configurations with four particles promoted to the pf shell (4p-4h in short). The SD band by 8p-8h configurations. The ground state of 40 Ca is strongly correlated, but the closed shell still amounts to 65%. The energies of the bands are very well reproduced by the calculations. The out-band transitions connecting the SD band with other states are very small and depend on the details of the mixing among the different np-nh configurations; in spite of that, the calculation describes them reasonably. For the in-band transition probabilities along the SD band, we predict a fairly constant transition quadrupole moment Q 0 (t)∼170 e fm 2 up to J=10 that decreases toward the higher spins. We submit also that the J=8 states of the deformed and superdeformed bands are maximally mixed

  16. Crystal structure and energy band and optical properties of phosphate Sr3P4O13

    International Nuclear Information System (INIS)

    Zhang, Y.-C.; Cheng, W.-D.; Wu, D.-S.; Zhang, H.; Chen, D.-G.; Gong, Y.-J.; Kan, Z.-G.

    2004-01-01

    A single crystal of the compound Sr 3 P 4 O 13 has been found and the crystal structure has been characterized by means of single crystal X-ray diffraction analysis. The compound crystallizes in triclinic system and belongs to space group P1-bar. It builds up from SrO 7 polyhedra and P 4 O 13 -6 anions and has a layered structure, and the Sr atoms are located in the interlayer space. The absorption and luminescence spectrum of Sr 3 P 4 O 13 microcrystals have been measured. The calculated results of crystal energy band structure by the DFT show that the solid state of Sr 3 P 4 O 13 is an isolator with direct band gap. The calculated total and partial density of states indicate that the top valence bands are contributions from P 3p and O 2p states and low conduction bands mostly originate from Sr atomic states. The calculated optical response functions expect that the Sr 3 P 4 O 13 is a low refractive index, and it is possible that the Sr 3 P 4 O 13 is used to make transparent material between the UV and FR light zone

  17. Positron and electron energy bands in several ionic crystals using restricted Hartree-Fock method

    Science.gov (United States)

    Kunz, A. B.; Waber, J. T.

    1981-08-01

    Using a restricted Hartree-Fock formalism and suitably localized and symmetrized wave functions, both the positron and electron energy bands were calculated for NaF, MgO and NiO. The lowest positron state at Γ 1 lies above the vacuum level and negative work functions are predicted. Positron annihilation rates were calculated and found to be in good agreement with measured lifetimes.

  18. Centrifugal stretching along the ground state band of 168Hf

    International Nuclear Information System (INIS)

    Costin, A.; Pietralla, N.; Reese, M.; Moeller, O.; Ai, H.; Casten, R. F.; Heinz, A.; McCutchan, E. A.; Meyer, D. A.; Qian, J.; Werner, V.; Dusling, K.; Fitzpatrick, C. R.; Guerdal, G.; Petkov, P.; Rainovski, G.

    2009-01-01

    The lifetimes of the J π =4 + , 6 + , 8 + , and 10 + levels along the ground state band in 168 Hf were measured by means of the recoil distance Doppler shift (RDDS) method using the New Yale Plunger Device (NYPD) and the SPEEDY detection array at Wright Nuclear Structure Laboratory of Yale University. Excited states in 168 Hf were populated using the 124 Sn( 48 Ti,4n) fusion evaporation reaction. The new lifetime values are sufficiently precise to clearly prove the increase of quadrupole deformation as a function of angular momentum in the deformed nucleus 168 Hf. The data agree with the predictions from the geometrical confined β-soft (CBS) rotor model that involves centrifugal stretching in a soft potential

  19. State Counting for Excited Bands of the Fractional Quantum Hall Effect: Exclusion Rules for Bound Excitons

    Science.gov (United States)

    Coimbatore Balram, Ajit; Wójs, Arkadiusz; Jain, Jainendra

    2014-03-01

    Exact diagonalization studies have revealed that the energy spectrum of interacting electrons in the lowest Landau level splits, non-perturbatively, into bands. The theory of nearly free composite fermions (CFs) has been shown to be valid for the lowest band, and thus to capture the low temperature physics, but it over-predicts the number of states for the excited bands. We explain the state counting of higher bands in terms of composite fermions with an infinitely strong short range interaction between a CF particle and a CF hole. This interaction, the form of which we derive from the microscopic CF theory, eliminates configurations containing certain tightly bound CF excitons. With this modification, the CF theory reproduces, for all well-defined excited bands, an exact counting for ν > 1 / 3 , and an almost exact counting for ν The resulting insight clarifies that the corrections to the nearly free CF theory are not thermodynamically significant at sufficiently low temperatures, thus providing a microscopic explanation for why it has proved successful for the analysis of the various properties of the CF Fermi sea. NSF grants DMR-1005536 and DMR-0820404, Polish NCN grant 2011/01/B/ST3/04504 and EU Marie Curie Grant PCIG09-GA-2011-294186, Research Computing and Cyberinfrastructure, PSU and Wroclaw Centre for Networking and Supercomputing

  20. Relativistic band-structure calculations for CeTIn sub 5 (T=Ir and Co) and analysis of the energy bands by using tight-binding method

    CERN Document Server

    Maehira, T; Ueda, K; Hasegawa, A

    2003-01-01

    In order to investigate electronic properties of recently discovered heavy fermion superconductors CeTIn sub 5 (T=Ir and Co), we employ the relativistic linear augmented-plane-wave (RLAPW) method to clarify the energy band structures and Fermi surfaces of those materials. The obtained energy bands mainly due to the large hybridization between Ce 4 f and In 5 p states well reproduce the Fermi surfaces consistent with the de Haas-van Alphen experimental results. However, when we attempt to understand magnetism and superconductively in CeTIn sub 5 from the microscopic viewpoint, the energy bands obtained in the RLAPW method are too complicated to analyze the system by further including electron correlations. Thus, it is necessary to prepare a more simplified model, keeping correctly the essential characters of the energy bands obtained in the band-structure calculation. For the purpose, we construct a tight-binding model for CeTIn sub 5 by including f-f and p-p hoppings as well as f-p hybridization, which are ex...

  1. Lateral energy band profile modulation in tunnel field effect transistors based on gate structure engineering

    Directory of Open Access Journals (Sweden)

    Ning Cui

    2012-06-01

    Full Text Available Choosing novel materials and structures is important for enhancing the on-state current in tunnel field-effect transistors (TFETs. In this paper, we reveal that the on-state performance of TFETs is mainly determined by the energy band profile of the channel. According to this interpretation, we present a new concept of energy band profile modulation (BPM achieved with gate structure engineering. It is believed that this approach can be used to suppress the ambipolar effect. Based on this method, a Si TFET device with a symmetrical tri-material-gate (TMG structure is proposed. Two-dimensional numerical simulations demonstrated that the special band profile in this device can boost on-state performance, and it also suppresses the off-state current induced by the ambipolar effect. These unique advantages are maintained over a wide range of gate lengths and supply voltages. The BPM concept can serve as a guideline for improving the performance of nanoscale TFET devices.

  2. Lifetimes of the low spin states in the superdeformed band of {sup 192}Hg

    Energy Technology Data Exchange (ETDEWEB)

    Lee, I Y; Baktash, C; Cullen, D; Garrett, J D; Johnson, N R; McGowan, F K; Winchell, D F [Oak Ridge National Lab., TN (United States); Yu, C H [Tennessee Univ., Knoxville, TN (United States)

    1992-08-01

    Superdeformed (SD) states with a 2:1 axis ratio have been observed in nuclei in the A = 150, 190, and the actinide regions. These states depopulate into normally deformed (ND) states by gamma decay, but so far the linking transitions have not been observed and the depopulation mechanism is not fully understood. Nuclei in different mass regions decay out at states with different spin (I), excitation energy above the ND yrast line (U) and lifetime {tau}. This variation is due to differences in the nuclear properties such as the barrier penetration probability, the level densities and the gamma transition strength of SD and ND states. One important factor is the competition between the collective E2 decay along the SD band and the statistical decay to the ND states. These transition rates, or the partial lifetimes, can be determined if the lifetime and the intensity of the gamma rays depopulating the SD states are known. (author). 4 refs., 2 tabs., 2 figs.

  3. Vibrational effects on surface energies and band gaps in hexagonal and cubic ice

    International Nuclear Information System (INIS)

    Engel, Edgar A.; Needs, Richard J.; Monserrat, Bartomeu

    2016-01-01

    Surface energies of hexagonal and cubic water ice are calculated using first-principles quantum mechanical methods, including an accurate description of anharmonic nuclear vibrations. We consider two proton-orderings of the hexagonal and cubic ice basal surfaces and three proton-orderings of hexagonal ice prism surfaces, finding that vibrations reduce the surface energies by more than 10%. We compare our vibrational densities of states to recent sum frequency generation absorption measurements and identify surface proton-orderings of experimental ice samples and the origins of characteristic absorption peaks. We also calculate zero point quantum vibrational corrections to the surface electronic band gaps, which range from −1.2 eV for the cubic ice basal surface up to −1.4 eV for the hexagonal ice prism surface. The vibrational corrections to the surface band gaps are up to 12% smaller than for bulk ice.

  4. NiTi shape memory via solid-state nudge-elastic band

    Science.gov (United States)

    Zarkevich, Nikolai A.; Johnson, Duane D.

    2014-03-01

    We determine atomic mechanisms of the shape memory effect in NiTi from a generalized solid-state nudge elastic band (SSNEB) method. We consider transformation between the austenite B2 and the ground-state base-centered orthorhombic (BCO) structures. In these pathways we obtain the R-phase and discuss its structure. We confirm that BCO is the ground state, and determine the pathways to BCO martensite, which dictate transition barriers. While ideal B2 is unstable, we find a B2-like NiTi high-temperature solid phase with significant local displacement disorder, which is B2 on average. This B2-like phase appears to be entropically stabilized. This work is supported by the U.S. Department of Energy, Office of Basic Energy Science, Division of Materials Science and Engineering. Ames Laboratory is operated for the U.S. DOE by Iowa State University under contract DE-AC02-07CH11358.

  5. Electron Elevator: Excitations across the Band Gap via a Dynamical Gap State.

    Science.gov (United States)

    Lim, A; Foulkes, W M C; Horsfield, A P; Mason, D R; Schleife, A; Draeger, E W; Correa, A A

    2016-01-29

    We use time-dependent density functional theory to study self-irradiated Si. We calculate the electronic stopping power of Si in Si by evaluating the energy transferred to the electrons per unit path length by an ion of kinetic energy from 1 eV to 100 keV moving through the host. Electronic stopping is found to be significant below the threshold velocity normally identified with transitions across the band gap. A structured crossover at low velocity exists in place of a hard threshold. An analysis of the time dependence of the transition rates using coupled linear rate equations enables one of the excitation mechanisms to be clearly identified: a defect state induced in the gap by the moving ion acts like an elevator and carries electrons across the band gap.

  6. Exotic superconductivity with enhanced energy scales in materials with three band crossings

    Science.gov (United States)

    Lin, Yu-Ping; Nandkishore, Rahul M.

    2018-04-01

    Three band crossings can arise in three-dimensional quantum materials with certain space group symmetries. The low energy Hamiltonian supports spin one fermions and a flat band. We study the pairing problem in this setting. We write down a minimal BCS Hamiltonian and decompose it into spin-orbit coupled irreducible pairing channels. We then solve the resulting gap equations in channels with zero total angular momentum. We find that in the s-wave spin singlet channel (and also in an unusual d-wave `spin quintet' channel), superconductivity is enormously enhanced, with a possibility for the critical temperature to be linear in interaction strength. Meanwhile, in the p-wave spin triplet channel, the superconductivity exhibits features of conventional BCS theory due to the absence of flat band pairing. Three band crossings thus represent an exciting new platform for realizing exotic superconducting states with enhanced energy scales. We also discuss the effects of doping, nonzero temperature, and of retaining additional terms in the k .p expansion of the Hamiltonian.

  7. Contributions of oxygen vacancies and titanium interstitials to band-gap states of reduced titania

    Science.gov (United States)

    Li, Jingfeng; Lazzari, Rémi; Chenot, Stéphane; Jupille, Jacques

    2018-01-01

    The spectroscopic fingerprints of the point defects of titanium dioxide remain highly controversial. Seemingly indisputable experiments lead to conflicting conclusions in which oxygen vacancies and titanium interstitials are alternately referred to as the primary origin of the Ti 3 d band-gap states. We report on experiments performed by electron energy loss spectroscopy whose key is the direct annealing of only the very surface of rutile TiO2(110 ) crystals and the simultaneous measurement of its temperature via the Bose-Einstein loss/gain ratio. By surface preparations involving reactions with oxygen and water vapor, in particular, under electron irradiation, vacancy- and interstitial-related band-gap states are singled out. Off-specular measurements reveal that both types of defects contribute to a unique charge distribution that peaks in subsurface layers with a common dispersive behavior.

  8. Trap density of states in n-channel organic transistors: variable temperature characteristics and band transport

    International Nuclear Information System (INIS)

    Cho, Joung-min; Akiyama, Yuto; Kakinuma, Tomoyuki; Mori, Takehiko

    2013-01-01

    We have investigated trap density of states (trap DOS) in n-channel organic field-effect transistors based on N,N ’-bis(cyclohexyl)naphthalene diimide (Cy-NDI) and dimethyldicyanoquinonediimine (DMDCNQI). A new method is proposed to extract trap DOS from the Arrhenius plot of the temperature-dependent transconductance. Double exponential trap DOS are observed, in which Cy-NDI has considerable deep states, by contrast, DMDCNQI has substantial tail states. In addition, numerical simulation of the transistor characteristics has been conducted by assuming an exponential trap distribution and the interface approximation. Temperature dependence of transfer characteristics are well reproduced only using several parameters, and the trap DOS obtained from the simulated characteristics are in good agreement with the assumed trap DOS, indicating that our analysis is self-consistent. Although the experimentally obtained Meyer-Neldel temperature is related to the trap distribution width, the simulation satisfies the Meyer-Neldel rule only very phenomenologically. The simulation also reveals that the subthreshold swing is not always a good indicator of the total trap amount, because it also largely depends on the trap distribution width. Finally, band transport is explored from the simulation having a small number of traps. A crossing point of the transfer curves and negative activation energy above a certain gate voltage are observed in the simulated characteristics, where the critical V G above which band transport is realized is determined by the sum of the trapped and free charge states below the conduction band edge

  9. Measurement of the band gap by reflection electron energy loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Vos, Maarten, E-mail: maarten.vos@anu.edu.au [Electronic Materials Engineering Department, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); King, Sean W. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); French, Benjamin L. [Ocotillo Materials Laboratory, Intel Corporation, Chandler, AZ 85248 (United States)

    2016-10-15

    Highlights: • Semiconductors are measured (without surface preparation) using REELS. • At low beam energies it is difficult to measure band gap due to surface impurities. • At very high energies it is difficult to measure band gap due to recoil effect. • At intermediate energies (around 5 keV) one obtains a good estimate of the band gap. - Abstract: We investigate the possibilities of measuring the band gap of a variety of semiconductors and insulators by reflection electron energy loss spectroscopy without additional surface preparation. The band gap is a bulk property, whereas reflection energy loss spectroscopy is generally considered a surface sensitive technique. By changing the energy of the incoming electrons, the degree of surface sensitivity can be varied. Here, we present case studies to determine the optimum condition for the determination of the band gap. At very large incoming electron energies recoil effects interfere with the band gap determination, whereas at very low energies surface effects are obscuring the band gap without surface preparation. Using an incoming energy of 5 keV a reasonable estimate of the band gap is obtained in most cases.

  10. Measurement of the band gap by reflection electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Vos, Maarten; King, Sean W.; French, Benjamin L.

    2016-01-01

    Highlights: • Semiconductors are measured (without surface preparation) using REELS. • At low beam energies it is difficult to measure band gap due to surface impurities. • At very high energies it is difficult to measure band gap due to recoil effect. • At intermediate energies (around 5 keV) one obtains a good estimate of the band gap. - Abstract: We investigate the possibilities of measuring the band gap of a variety of semiconductors and insulators by reflection electron energy loss spectroscopy without additional surface preparation. The band gap is a bulk property, whereas reflection energy loss spectroscopy is generally considered a surface sensitive technique. By changing the energy of the incoming electrons, the degree of surface sensitivity can be varied. Here, we present case studies to determine the optimum condition for the determination of the band gap. At very large incoming electron energies recoil effects interfere with the band gap determination, whereas at very low energies surface effects are obscuring the band gap without surface preparation. Using an incoming energy of 5 keV a reasonable estimate of the band gap is obtained in most cases.

  11. Conduction bands and invariant energy gaps in alkali bromides

    NARCIS (Netherlands)

    Boer, P.K. de; Groot, R.A. de

    1998-01-01

    Electronic structure calculations of the alkali bromides LiBr, NaBr, KBr, RbBr and CsBr are reported. It is shown that the conduction band has primarily bromine character. The size of the band gaps of bromides and alkali halides in general is reinterpreted.

  12. Energy shift and conduction-to-valence band transition mediated by a time-dependent potential barrier in graphene

    Science.gov (United States)

    Chaves, Andrey; da Costa, D. R.; de Sousa, G. O.; Pereira, J. M.; Farias, G. A.

    2015-09-01

    We investigate the scattering of a wave packet describing low-energy electrons in graphene by a time-dependent finite-step potential barrier. Our results demonstrate that, after Klein tunneling through the barrier, the electron acquires an extra energy which depends on the rate of change of the barrier height with time. If this rate is negative, the electron loses energy and ends up as a valence band state after leaving the barrier, which effectively behaves as a positively charged quasiparticle.

  13. Metal-induced gap states in ferroelectric capacitors and its relationship with complex band structures

    Science.gov (United States)

    Junquera, Javier; Aguado-Puente, Pablo

    2013-03-01

    At metal-isulator interfaces, the metallic wave functions with an energy eigenvalue within the band gap decay exponentially inside the dielectric (metal-induced gap states, MIGS). These MIGS can be actually regarded as Bloch functions with an associated complex wave vector. Usually only real values of the wave vectors are discussed in text books, since infinite periodicity is assumed and, in that situation, wave functions growing exponentially in any direction would not be physically valid. However, localized wave functions with an exponential decay are indeed perfectly valid solution of the Schrodinger equation in the presence of defects, surfaces or interfaces. For this reason, properties of MIGS have been typically discussed in terms of the complex band structure of bulk materials. The probable dependence on the interface particulars has been rarely taken into account explicitly due to the difficulties to include them into the model or simulations. We aim to characterize from first-principles simulations the MIGS in realistic ferroelectric capacitors and their connection with the complex band structure of the ferroelectric material. We emphasize the influence of the real interface beyond the complex band structure of bulk materials. Financial support provided by MICINN Grant FIS2009-12721-C04-02, and by the European Union Grant No. CP-FP 228989-2 ``OxIDes''. Computer resources provided by the RES.

  14. Dipole bands in high spin states of {sub 57}{sup 135}La{sub 78}

    Energy Technology Data Exchange (ETDEWEB)

    Garg, Ritika; Kumar, S.; Saxena, Mansi; Goyal, Savi; Siwal, Davinder; Verma, S.; Mandal, S. [Department of Physics and Astrophysics, University of Delhi, Delhi - 110007 (India); Palit, R.; Saha, Sudipta; Sethi, J.; Sharma, Sushil K.; Trivedi, T.; Jadav, S. K.; Donthi, R.; Naidu, B. S. [Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai - 400005 (India)

    2014-08-14

    High spin states of {sup 135}La have been investigated using the reaction {sup 128}Te({sup 11}B,4n){sup 135}La at a beam energy of 50.5 MeV. Two negative parity dipole bands (ΔI = 1) have been established. Crossover E2 transitions have been observed for the first time in one of the dipole bands. For the Tilted Axis Cranking (TAC) calculations, a three-quasiparticle (3qp) configuration π(h{sub 11/2}){sup 1}⊗ν(h{sub 11/2}){sup −2} and a five-quasiparticle (5qp) configuration π(h{sub 11/2}){sup 1}(g{sub 7/2}/d{sub 5/2}){sup 2}⊗ν(h{sub 11/2}){sup −2} have been taken for the two negative parity dipole bands. The comparison of experimental observables with TAC calculations supports the configuration assignments for both the dipole bands.

  15. Sustainable energy in Baltic States

    International Nuclear Information System (INIS)

    Klevas, Valentinas; Streimikiene, Dalia; Grikstaite, Ramute

    2007-01-01

    Integration of New Member States to the European Union has created a new situation in the frame of implementation of the Lisbon strategy and EU Sustainable Development. The closure of Ignalina NPP is the biggest challenge to the energy sector development of the Baltic States. The Baltic States have quite limited own energy resources and in the Accession agreement with the EU Lithuania, Latvia and Estonia have verified their targets to increase the share of electricity produced from renewable energy sources (RES-E) by the year 2010. A wider use of renewable energy and increase of energy efficiency can make a valuable contribution to meeting the targets of sustainable development. The article presents a detailed overview of the present policies and measures implemented in the Baltic States, aiming to support the use of RES and the increase of energy efficiency. The review of possibilities to use the EU Structural Funds (SF) for the implementation of sustainable energy projects in the Baltic States was performed.The use of regional social-economic-environmental indicators is the main key to integrate sustainable energy development at the program deployment level. The indicators to be used should describe the contribution of energy programs to the sustainable development, medium- and long-term trends and inter-relationship between them and the typical energy indicators (saved toe, improved energy efficiency, percentage of RES). Municipalities may play a considerable role by promoting sustainable energy since local authorities are fulfilling their functions in the energy sector via a number of roles. The Netherlands' example shows that municipalities may act as facilitators by implementing national environmental policy and increasing energy efficiency in an integral part of these activities. The guidelines for Lithuanian local sustainable energy development using the SF co-financing have been presented

  16. Ground-State Band and Deformation of the Z = 102 Isotope N 254

    International Nuclear Information System (INIS)

    Reiter, P.; Khoo, T.L.; Lister, C.J.; Seweryniak, D.; Ahmad, I.; Alcorta, M.; Carpenter, M.P.; Cizewski, J.A.; Davids, C.N.; Gervais, G.; Greene, J.P.; Henning, W.F.; Janssens, R.V.; Lauritsen, T.; Siem, S.; Sonzogni, A.A.; Sullivan, D.; Uusitalo, J.; Wiedenhoever, I.; Amzal, N.; Butler, P.A.; Chewter, A.J.; Greenlees, P.T.; Herzberg, R.; Jones, G.D.; Cizewski, J.A.; Ding, K.Y.; Fotiades, N.; Fox, J.D.; Korten, W.; Leino, M.; Vetter, K.; Siem, S.

    1999-01-01

    The ground-state band of the Z=102 isotope 254 No has been identified up to spin 14, indicating that the nucleus is deformed. The deduced quadrupole deformation, β=0.27 , is in agreement with theoretical predictions. These observations confirm that the shell-correction energy responsible for the stability of transfermium nuclei is partly derived from deformation. The survival of 254 No up to spin 14 means that its fission barrier persists at least up to that spin. copyright 1999 The American Physical Society

  17. Determination of shift in energy of band edges and band gap of ZnSe spherical quantum dot

    Science.gov (United States)

    Siboh, Dutem; Kalita, Pradip Kumar; Sarma, Jayanta Kumar; Nath, Nayan Mani

    2018-04-01

    We have determined the quantum confinement induced shifts in energy of band edges and band gap with respect to size of ZnSe spherical quantum dot employing an effective confinement potential model developed in our earlier communication "arXiv:1705.10343". We have also performed phenomenological analysis of our theoretical results in comparison with available experimental data and observe a very good agreement in this regard. Phenomenological success achieved in this regard confirms validity of the confining potential model as well as signifies the capability and applicability of the ansatz for the effective confining potential to have reasonable information in the study of real nano-structured spherical systems.

  18. Determining the band gap and mean kinetic energy of atoms from reflection electron energy loss spectra

    Energy Technology Data Exchange (ETDEWEB)

    Vos, M. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, Australian National University, Canberra ACT (Australia); Marmitt, G. G. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, Australian National University, Canberra ACT (Australia); Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Finkelstein, Y. [Nuclear Research Center — Negev, Beer-Sheva 84190 (Israel); Moreh, R. [Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)

    2015-09-14

    Reflection electron energy loss spectra from some insulating materials (CaCO{sub 3}, Li{sub 2}CO{sub 3}, and SiO{sub 2}) taken at relatively high incoming electron energies (5–40 keV) are analyzed. Here, one is bulk sensitive and a well-defined onset of inelastic excitations is observed from which one can infer the value of the band gap. An estimate of the band gap was obtained by fitting the spectra with a procedure that includes the recoil shift and recoil broadening affecting these measurements. The width of the elastic peak is directly connected to the mean kinetic energy of the atom in the material (Doppler broadening). The experimentally obtained mean kinetic energies of the O, C, Li, Ca, and Si atoms are compared with the calculated ones, and good agreement is found, especially if the effect of multiple scattering is taken into account. It is demonstrated experimentally that the onset of the inelastic excitation is also affected by Doppler broadening. Aided by this understanding, we can obtain a good fit of the elastic peak and the onset of inelastic excitations. For SiO{sub 2}, good agreement is obtained with the well-established value of the band gap (8.9 eV) only if it is assumed that the intensity near the edge scales as (E − E{sub gap}){sup 1.5}. For CaCO{sub 3}, the band gap obtained here (7 eV) is about 1 eV larger than the previous experimental value, whereas the value for Li{sub 2}CO{sub 3} (7.5 eV) is the first experimental estimate.

  19. Determining the band gap and mean kinetic energy of atoms from reflection electron energy loss spectra

    International Nuclear Information System (INIS)

    Vos, M.; Marmitt, G. G.; Finkelstein, Y.; Moreh, R.

    2015-01-01

    Reflection electron energy loss spectra from some insulating materials (CaCO 3 , Li 2 CO 3 , and SiO 2 ) taken at relatively high incoming electron energies (5–40 keV) are analyzed. Here, one is bulk sensitive and a well-defined onset of inelastic excitations is observed from which one can infer the value of the band gap. An estimate of the band gap was obtained by fitting the spectra with a procedure that includes the recoil shift and recoil broadening affecting these measurements. The width of the elastic peak is directly connected to the mean kinetic energy of the atom in the material (Doppler broadening). The experimentally obtained mean kinetic energies of the O, C, Li, Ca, and Si atoms are compared with the calculated ones, and good agreement is found, especially if the effect of multiple scattering is taken into account. It is demonstrated experimentally that the onset of the inelastic excitation is also affected by Doppler broadening. Aided by this understanding, we can obtain a good fit of the elastic peak and the onset of inelastic excitations. For SiO 2 , good agreement is obtained with the well-established value of the band gap (8.9 eV) only if it is assumed that the intensity near the edge scales as (E − E gap ) 1.5 . For CaCO 3 , the band gap obtained here (7 eV) is about 1 eV larger than the previous experimental value, whereas the value for Li 2 CO 3 (7.5 eV) is the first experimental estimate

  20. Calculation of Energy Band Diagram of a Photoelectrochemical Water Splitting Cell

    OpenAIRE

    Cendula, P.; Tilley, S. D.; Gimenez, S.; Schmid, M.; Bisquert, J.; Graetzel, M.; Schumacher, J. O.

    2014-01-01

    A physical model is presented for a semiconductor electrode of a photoelectrochemical (PEC) cell, accounting for the potential drop in the Helmholtz layer. Hence both band edge pinning and unpinning are naturally included in our description. The model is based on the continuity equations for charge carriers and direct charge transfer from the energy bands to the electrolyte. A quantitative calculation of the position of the energy bands and the variation of the quasi-Fermi levels in the semic...

  1. Touching points in the energy band structure of bilayer graphene superlattices

    International Nuclear Information System (INIS)

    Pham, C Huy; Nguyen, V Lien

    2014-01-01

    The energy band structure of the bilayer graphene superlattices with zero-averaged periodic δ-function potentials are studied within the four-band continuum model. Using the transfer matrix method, the study is mainly focused on examining the touching points between adjacent minibands. For the zero-energy touching points the dispersion relation derived shows a Dirac-like double-cone shape with the group velocity which is periodic in the potential strength P with the period of π and becomes anisotropic at relatively large P. From the finite-energy touching points we have identified those located at zero wave-number. It was shown that for these finite-energy touching points the dispersion is direction-dependent in the sense that it is linear or parabolic in the direction parallel or perpendicular to the superlattice direction, respectively. We have also calculated the density of states and the conductivity which demonstrates a manifestation of the touching points examined. (paper)

  2. Quasiparticle band gap of organic-inorganic hybrid perovskites: Crystal structure, spin-orbit coupling, and self-energy effects

    Science.gov (United States)

    Gao, Weiwei; Gao, Xiang; Abtew, Tesfaye A.; Sun, Yi-Yang; Zhang, Shengbai; Zhang, Peihong

    2016-02-01

    The quasiparticle band gap is one of the most important materials properties for photovoltaic applications. Often the band gap of a photovoltaic material is determined (and can be controlled) by various factors, complicating predictive materials optimization. An in-depth understanding of how these factors affect the size of the gap will provide valuable guidance for new materials discovery. Here we report a comprehensive investigation on the band gap formation mechanism in organic-inorganic hybrid perovskites by decoupling various contributing factors which ultimately determine their electronic structure and quasiparticle band gap. Major factors, namely, quasiparticle self-energy, spin-orbit coupling, and structural distortions due to the presence of organic molecules, and their influences on the quasiparticle band structure of organic-inorganic hybrid perovskites are illustrated. We find that although methylammonium cations do not contribute directly to the electronic states near band edges, they play an important role in defining the band gap by introducing structural distortions and controlling the overall lattice constants. The spin-orbit coupling effects drastically reduce the electron and hole effective masses in these systems, which is beneficial for high carrier mobilities and small exciton binding energies.

  3. Mixed State of a Dirty Two-Band Superconductor: Application to MgB2

    NARCIS (Netherlands)

    Koshelev, A.E.; Golubov, Alexandre Avraamovitch

    2003-01-01

    We investigate the vortex state in a two-band superconductor with strong intraband and weak interband electronic scattering rates. Coupled Usadel equations are solved numerically, and the distributions of the pair potentials and local densities of states are calculated for two bands at different

  4. Theory of two-photon absorption by exciton states in cubic semiconductors with degenerate valence bands

    International Nuclear Information System (INIS)

    Nguyen Ai Viet; Nguyen Toan Thang.

    1987-06-01

    The coefficient of the absorption of two polarized photons is calculated for direct band gap semiconductors with degenerate valence bands. Wannier-Mott exciton states are included in both the intermediate and final states. Numerical calculations are performed for ZnSe and are compared with Sondergeld's experimental and theoretical results. (author). 11 refs, 2 tabs

  5. S-band 300 W pulsed solid state microwave amplifier development for driving high power klystrons for electron accelerators

    International Nuclear Information System (INIS)

    Mohania, Praveen; Shrivastava, Purushottam; Hannurkar, P.R.

    2005-01-01

    S-Band Microwave electron accelerators like microtrons and linear accelerators need pulsed microwaves from few megawatts to tens of megawatts to accelerator the electrons to desired energy and intensity. Klystron tube based driver amplifiers were used to drive the high power klystrons, which need microwave power from few tens of watts to 1 kW depending on tube output power and gain. A endeavour was initiated at Centre for Advanced Technology to develop state of art solid state S-band microwave amplifiers indigenously to drive the klystron tubes. A modular design approach was used and individual modules up to 160 W power levels were developed and tested. Finally combining 160 W modules will give up to 300 W output power. Several more modules can be combined to achieve even high power levels. Present paper describes the developmental efforts of 300 W S-band solid-state amplifiers and related microwave technologies. (author)

  6. A new perspective of ground band energy formulae

    Indian Academy of Sciences (India)

    J B GUPTA

    2017-08-07

    Aug 7, 2017 ... Nuclear structure; ground band; moment of inertia; softness parameter. PACS Nos 21.60 ... mary data on the spectral properties of atomic nuclei. ... poorer at higher spins and for shape transitional (in ... 25 and figure 4.11 on p.

  7. Calculations of intersection cross-slip activation energies in fcc metals using nudged elastic band method

    International Nuclear Information System (INIS)

    Rao, S.I.; Dimiduk, D.M.; Parthasarathy, T.A.; El-Awady, J.; Woodward, C.; Uchic, M.D.

    2011-01-01

    The nudged elastic band (NEB) method is used to evaluate activation energies for dislocation intersection cross-slip in face-centered cubic (fcc) nickel and copper, to extend our prior work which used an approximate method. In this work we also extend the study by including Hirth locks (HL) in addition to Lomer-Cottrell locks and glide locks (GL). Using atomistic (molecular statics) simulations with embedded atom potentials we evaluated the activation barrier for a dislocation to transform from fully residing on the glide plane to fully residing on the cross-slip plane when intersecting a 120 o forest dislocation in both Ni and Cu. The initial separation between the screw and the intersecting dislocation on the (1 1 1) glide plane is varied to find a minimum in the activation energy. The NEB method gives energies that are ∼10% lower than those reported in our prior work. It is estimated that the activation energies for cross-slip from the fully glide plane state to the partially cross-slipped state at the 120 o intersection forming GL in Ni and Cu are ∼0.47 and ∼0.65 eV, respectively, and from the fully cross-slip plane state to the partially cross-slipped state forming LC are ∼0.68 and ∼0.67 eV. The activation energies for cross-slip from the fully glide plane state to the partially cross-slipped state at the 120 o intersection forming HL in Ni and Cu are estimated to be ∼0.09 and ∼0.31 eV, respectively. These values are a factor of 3-20 lower than the activation energy for bulk cross-slip in Ni and, a factor of 2-6 lower than the activation energy for cross-slip in Cu estimated by Friedel-Escaig analysis. These results suggest that cross-slip should nucleate preferentially at selected screw dislocation intersections in fcc materials and the activation energies for such mechanisms are also a function of stacking fault energy.

  8. Calculation of Energy Diagram of Asymmetric Graded-Band-Gap Semiconductor Superlattices.

    Science.gov (United States)

    Monastyrskii, Liubomyr S; Sokolovskii, Bogdan S; Alekseichyk, Mariya P

    2017-12-01

    The paper theoretically investigates the peculiarities of energy diagram of asymmetric graded-band-gap superlattices with linear coordinate dependences of band gap and electron affinity. For calculating the energy diagram of asymmetric graded-band-gap superlattices, linearized Poisson's equation has been solved for the two layers forming a period of the superlattice. The obtained coordinate dependences of edges of the conduction and valence bands demonstrate substantial transformation of the shape of the energy diagram at changing the period of the lattice and the ratio of width of the adjacent layers. The most marked changes in the energy diagram take place when the period of lattice is comparable with the Debye screening length. In the case when the lattice period is much smaller that the Debye screening length, the energy diagram has the shape of a sawtooth-like pattern.

  9. Importance of complex band structure and resonant states for tunneling

    Czech Academy of Sciences Publication Activity Database

    Dederichs, P. H.; Mavropoulos, Ph.; Wunnicke, O.; Papanikolaou, N.; Bellini, V.; Zeller, R.; Drchal, Václav; Kudrnovský, Josef

    2002-01-01

    Roč. 240, - (2002), s. 108-113 ISSN 0304-8853 R&D Projects: GA AV ČR IAA1010829; GA ČR GA202/00/0122; GA MŠk OC P5.30 Grant - others:TSR(XX) 01398 Institutional research plan: CEZ:AV0Z1010914 Keywords : magnetoresistance * tunneling * band structure * interface effects Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.046, year: 2002

  10. The baltic states' energy system

    OpenAIRE

    Nikitaravičius, Martynas

    2006-01-01

    THE BALTIC STATES’ ENERGY SYSTEM SUMMARY The goal of paper – the comparative analysis of Baltic states‘ (i.e. of Lithuania, Latvia, Estonia) energy systems in 1990-2004. The main causes that affected the development of Baltic states’ energetics are indicated in this work. By the method of statistical analysis, the comparative advantages of Baltic states‘ energetics are detected. Moreover, the main trends of further development of integration of Baltic states ‘ energetics into the energetics o...

  11. The behaviour of the moment of inertia curve in a recrossing of the ground state band and the super band in 158Er

    International Nuclear Information System (INIS)

    Dracoulis, G.D.

    1978-11-01

    The recrossing of the ground state band with the super band as an explanation for the second anomaly in 158 Er is examined in terms of the moment of inertia. A two band mixing calculation does not reproduce the experimenal moment of inertia curve

  12. Baseline brain energy supports the state of consciousness.

    Science.gov (United States)

    Shulman, Robert G; Hyder, Fahmeed; Rothman, Douglas L

    2009-07-07

    An individual, human or animal, is defined to be in a conscious state empirically by the behavioral ability to respond meaningfully to stimuli, whereas the loss of consciousness is defined by unresponsiveness. PET measurements of glucose or oxygen consumption show a widespread approximately 45% reduction in cerebral energy consumption with anesthesia-induced loss of consciousness. Because baseline brain energy consumption has been shown by (13)C magnetic resonance spectroscopy to be almost exclusively dedicated to neuronal signaling, we propose that the high level of brain energy is a necessary property of the conscious state. Two additional neuronal properties of the conscious state change with anesthesia. The delocalized fMRI activity patterns in rat brain during sensory stimulation at a higher energy state (close to the awake) collapse to a contralateral somatosensory response at lower energy state (deep anesthesia). Firing rates of an ensemble of neurons in the rat somatosensory cortex shift from the gamma-band range (20-40 Hz) at higher energy state to energy state. With the conscious state defined by the individual's behavior and maintained by high cerebral energy, measurable properties of that state are the widespread fMRI patterns and high frequency neuronal activity, both of which support the extensive interregional communication characteristic of consciousness. This usage of high brain energies when the person is in the "state" of consciousness differs from most studies, which attend the smaller energy increments observed during the stimulations that form the "contents" of that state.

  13. Loss energy states of nonstationary quantum systems

    International Nuclear Information System (INIS)

    Dodonov, V.V.; Man'ko, V.I.

    1978-01-01

    The concept of loss energy states is introduced. The loss energy states of the quantum harmonic damping oscillator are considered in detail. The method of constructing the loss energy states for general multidimensional quadratic nonstationary quantum systems is briefly discussed

  14. Photoconductivities from band states and a dissipative electron dynamics: Si(111) without and with adsorbed Ag clusters

    International Nuclear Information System (INIS)

    Vazhappilly, Tijo; Hembree, Robert H.; Micha, David A.

    2016-01-01

    A new general computational procedure is presented to obtain photoconductivities starting from atomic structures, combining ab initio electronic energy band states with populations from density matrix theory, and implemented for a specific set of materials based on Si crystalline slabs and their nanostructured surfaces without and with adsorbed Ag clusters. The procedure accounts for charge mobility in semiconductors in photoexcited states, and specifically electron and hole photomobilities at Si(111) surfaces with and without adsorbed Ag clusters using ab initio energy bands and orbitals generated from a generalized gradient functional, however with excited energy levels modified to provide correct bandgaps. Photoexcited state populations for each band and carrier type were generated using steady state solution of a reduced density matrix which includes dissipative medium effects. The present calculations provide photoexcited electronic populations and photoinduced mobilities resulting from applied electric fields and obtained from the change of driven electron energies with their electronic momentum. Extensive results for Si slabs with 8 layers, without and with adsorbed Ag clusters, show that the metal adsorbates lead to substantial increases in the photomobility and photoconductivity of electrons and holes

  15. Investigation of level energies and B(E2) values for rotation-aligned bands in Hg isotopes

    International Nuclear Information System (INIS)

    Mertin, D.; Tischler, R.; Kleinrahm, A.; Kroth, R.; Huebel, H.; Guenther, C.

    1978-01-01

    High spin states in 191 192 193 195 197 199 Hg were investigated by observing γ-rays and conversion electrons in the compound reactions 192 194 198 Pt(α,xn) and 192 Pt ( 3 He,4n). In 197 Hg the decoupled band built on the 13/2 + state and the semi-decoupled negative-parity band are observed up to Isup(π)=41/2 + and 33/2 - , respectively. A careful investigation of 199 Hg revealed no new high spin states above the previously known levels with Isup(π)=25/2 + and 31/2 - . Half-lives were determined for the 10 + , 7 - , 8 - and 16 - states in 192 Hg, the 33/2 states in 191 193 Hg and the 25/2 - states in 191 193 195 197 Hg. The systematics of the level energies and B(E2) values for the positive parity ground and 13/2 + bands and the negative-parity semi-decoupled bands in 190-200 Hg is discussed. (Auth.)

  16. A Combined Theoretical and Experimental View on Valence and Conduction Band Densities of States of Lead Halide Perovskites

    Science.gov (United States)

    Kronik, Leeor; Endres, James; Egger, David A.; Kulbak, Michael; Kerner, Ross A.; Zhao, Lianfeng; Silver, Scott H.; Hodes, Gary; Rand, Barry P.; Cahen, David; Kahn, Antoine

    We present results for the valence and conduction band density of states (DOS), measured via ultraviolet and inverse photoemission spectroscopies for three lead halide perovskites. Specifically, the DOS of MAPbI3, MAPbBr3, and CsPbBr3, grown on different substrates, are compared. Theoretical DOS, calculated via hybrid density functional theory and including spin-orbit coupling, are compared to experimental data. The agreement between experiment and theory, obtained after correcting the latter for quantitative discrepancies, leads to the identification of valence and conduction band spectral features. In particular, this comparison allows for precise determination of the energy position of the band edges, namely ionization energies and electron affinities of these materials. We find an unusually low DOS at the valence band maximum (VBM) of these systems, which confirms and generalizes previous findings of strong band dispersion and low DOS at the VBM of MAPbI3. This calls for special attention when using electron spectroscopy to determine the frontier electronic states of lead halide perovskites.

  17. Energy band alignment of antiferroelectric (Pb,La)(Zr,Sn,Ti)O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Andreas, E-mail: aklein@surface.tu-darmstadt.de [Technische Universität Darmstadt, Institute of Materials Science, Surface Science Division, Jovanka-Bontschits-Straße 2, 64287 Darmstadt (Germany); Lohaus, Christian [Technische Universität Darmstadt, Institute of Materials Science, Surface Science Division, Jovanka-Bontschits-Straße 2, 64287 Darmstadt (Germany); Reiser, Patrick [Technische Universität Darmstadt, Institute of Materials Science, Surface Science Division, Jovanka-Bontschits-Straße 2, 64287 Darmstadt (Germany); InnovationLab GmbH, Speyerer Straße 4, 69115 Heidelberg (Germany); Dimesso, Lucangelo [Technische Universität Darmstadt, Institute of Materials Science, Surface Science Division, Jovanka-Bontschits-Straße 2, 64287 Darmstadt (Germany); Wang, Xiucai; Yang, Tongqing [Tongji University, Key Laboratory of Advanced Civil Engineering Materials (Ministry of Education), Functional Materials Research Laboratory, College of Materials Science and Engineering, Cao’an Road 4800, Shanghai 201804 (China)

    2017-06-15

    Highlights: • Energy band alignment of antiferroelectric PLZST studied by XPS. • A deconvolution procedure is applied to study band alignment of insulating materials. • Contribution of Pb 6s orbitals leads to higher valence band maximum. • Ferroelectric polarization does not contribute to valence band maximum energy. • The variation of Schottky barrier heights indicates no Fermi level pinning in PLZST. - Abstract: The energy band alignment of antiferroelectric (Pb,La)(Zr,Sn,Ti)O{sub 3} is studied with photoelectron spectroscopy using interfaces with high work function RuO{sub 2} and low work function Sn-doped In{sub 2}O{sub 3} (ITO). It is demonstrated how spectral deconvolution can be used to determine absolute Schottky barrier heights for insulating materials with a high accuracy. Using this approach it is found that the valence band maximum energy of (Pb,La)(Zr,Sn,Ti)O{sub 3} is found to be comparable to that of Pb- and Bi-containing ferroelectric materials, which is ∼1 eV higher than that of BaTiO{sub 3}. The results provide additional evidence for the occupation of the 6s orbitals as origin of the higher valence band maximum, which is directly related to the electrical properties of such compounds. The results also verify that the energy band alignment determined by photoelectron spectroscopy of as-deposited electrodes is not influenced by polarisation. The electronic structure of (Pb,La)(Zr,Sn,Ti)O{sub 3} should enable doping of the material without strongly modifying its insulating properties, which is crucial for high energy density capacitors. Moreover, the position of the energy bands should result in a great freedom of selecting electrode materials in terms of avoiding charge injection.

  18. Effective Ginzburg–Landau free energy functional for multi-band isotropic superconductors

    International Nuclear Information System (INIS)

    Grigorishin, Konstantin V.

    2016-01-01

    Highlights: • The intergradient coupling of order parameters in a two-band superconductor plays important role and cannot be neglected. • A two-band superconductor must be characterized with a single coherence length and a single Ginzburg–Landau parameter. • Type-1.5 superconductors are impossible. • The free energy functional for a multi-band superconductor can be reduced to the effective single-band Ginzburg–Landau functional. - Abstract: It has been shown that interband mixing of gradients of two order parameters (drag effect) in an isotropic bulk two-band superconductor plays important role – such a quantity of the intergradients coupling exists that the two-band superconductor is characterized with a single coherence length and a single Ginzburg–Landau (GL) parameter. Other quantities or neglecting of the drag effect lead to existence of two coherence lengths and dynamical instability due to violation of the phase relations between the order parameters. Thus so-called type-1.5 superconductors are impossible. An approximate method for solving of set of GL equations for a multi-band superconductor has been developed: using the result about the drag effect it has been shown that the free-energy functional for a multi-band superconductor can be reduced to the GL functional for an effective single-band superconductor.

  19. Using the Elements of Cooperative Learning in School Band Classes in the United States

    Science.gov (United States)

    Whitener, John L.

    2016-01-01

    The purpose of this article is to answer the question of how we might use the elements of cooperative learning in school band classes in the United States. Current school band programs use age-old traditions that overemphasize group and individual competitiveness, stress large ensemble performance at the expense of all other activities, are…

  20. Application of energies of optimal frequency bands for fault diagnosis based on modified distance function

    Energy Technology Data Exchange (ETDEWEB)

    Zamanian, Amir Hosein [Southern Methodist University, Dallas (United States); Ohadi, Abdolreza [Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of)

    2017-06-15

    Low-dimensional relevant feature sets are ideal to avoid extra data mining for classification. The current work investigates the feasibility of utilizing energies of vibration signals in optimal frequency bands as features for machine fault diagnosis application. Energies in different frequency bands were derived based on Parseval's theorem. The optimal feature sets were extracted by optimization of the related frequency bands using genetic algorithm and a Modified distance function (MDF). The frequency bands and the number of bands were optimized based on the MDF. The MDF is designed to a) maximize the distance between centers of classes, b) minimize the dispersion of features in each class separately, and c) minimize dimension of extracted feature sets. The experimental signals in two different gearboxes were used to demonstrate the efficiency of the presented technique. The results show the effectiveness of the presented technique in gear fault diagnosis application.

  1. The use of bulk states to accelerate the band edge state calculation of a semiconductor quantum dot

    International Nuclear Information System (INIS)

    Voemel, Christof; Tomov, Stanimire Z.; Wang, Lin-Wang; Marques, Osni A.; Dongarra, Jack J.

    2007-01-01

    We present a new technique to accelerate the convergence of the folded spectrum method in empirical pseudopotential band edge state calculations for colloidal quantum dots. We use bulk band states of the materials constituent of the quantum dot to construct initial vectors and a preconditioner. We apply these to accelerate the convergence of the folded spectrum method for the interior states at the top of the valence and the bottom of the conduction band. For large CdSe quantum dots, the number of iteration steps until convergence decreases by about a factor of 4 compared to previous calculations

  2. The effect of density-of-state tails on band-to-band tunneling: Theory and application to tunnel field effect transistors

    Science.gov (United States)

    Sant, S.; Schenk, A.

    2017-10-01

    It is demonstrated how band tail states in the semiconductor influence the performance of a Tunnel Field Effect Transistor (TFET). As a consequence of the smoothened density of states (DOS) around the band edges, the energetic overlap of conduction and valence band states occurs gradually at the onset of band-to-band tunneling (BTBT), thus degrading the sub-threshold swing (SS) of the TFET. The effect of the band tail states on the current-voltage characteristics is modelled quantum-mechanically based on the idea of zero-phonon trap-assisted tunneling between band and tail states. The latter are assumed to arise from a 3-dimensional pseudo-delta potential proposed by Vinogradov [1]. This model potential allows the derivation of analytical expressions for the generation rate covering the whole range from very strong to very weak localization of the tail states. Comparison with direct BTBT in the one-band effective mass approximation reveals the essential features of tail-to-band tunneling. Furthermore, an analytical solution for the problem of tunneling from continuum states of the disturbed DOS to states in the opposite band is found, and the differences to direct BTBT are worked out. Based on the analytical expressions, a semi-classical model is implemented in a commercial device simulator which involves numerical integration along the tunnel paths. The impact of the tail states on the device performance is analyzed for a nanowire Gate-All-Around TFET. The simulations show that tail states notably impact the transfer characteristics of a TFET. It is found that exponentially decaying band tails result in a stronger degradation of the SS than tail states with a Gaussian decay of their density. The developed model allows more realistic simulations of TFETs including their non-idealities.

  3. Production of events with two or three muons in the final state during the interaction on nucleons of neutrinos and anti-neutrinos of the CERN narrow band beam with a maximum energy of 200 GeV

    International Nuclear Information System (INIS)

    Maillard, Jacques.

    1979-03-01

    A study was made of the production of dimuons and trimuons in the neutrino interactions using the data of the CDHS (CERN-Dortmund-Heidelberg-Saclay Cooperation) experiment taken in the CERN narrow band beam. The analysis of the quick results (since the statistics are weak) leads to significant conclusions on these events: 1) the c quark fragmentation function is approximately flat, 2) the production of heavy leptons, if this exists, only represents a very small part of the charged currents (10 -4 approximately). 3) the pair production of charmed quarks can explain some of the dimuons of same sign, the greater part of these events coming from the semi leptonic disintegration of pions and kaons (π→μν,K → μν) produced in the hadronic jet. 4) any other process (for instance the production of b quarks) is very weak ( -3 of the charged currents) [fr

  4. Superlattice band structure: New and simple energy quantification condition

    Energy Technology Data Exchange (ETDEWEB)

    Maiz, F., E-mail: fethimaiz@gmail.com [University of Cartage, Nabeul Engineering Preparatory Institute, Merazka, 8000 Nabeul (Tunisia); King Khalid University, Faculty of Science, Physics Department, P.O. Box 9004, Abha 61413 (Saudi Arabia)

    2014-10-01

    Assuming an approximated effective mass and using Bastard's boundary conditions, a simple method is used to calculate the subband structure for periodic semiconducting heterostructures. Our method consists to derive and solve the energy quantification condition (EQC), this is a simple real equation, composed of trigonometric and hyperbolic functions, and does not need any programming effort or sophistic machine to solve it. For less than ten wells heterostructures, we have derived and simplified the energy quantification conditions. The subband is build point by point; each point presents an energy level. Our simple energy quantification condition is used to calculate the subband structure of the GaAs/Ga{sub 0.5}Al{sub 0.5}As heterostructures, and build its subband point by point for 4 and 20 wells. Our finding shows a good agreement with previously published results.

  5. Experimental observation on asymmetric energy flux within the forbidden frequency band in the LC transmission line

    International Nuclear Information System (INIS)

    Tao Feng; Chen Weizhong; Pan Junting; Xu Wen; Du Sidan

    2012-01-01

    We study the energy flux in a nonlinear electrical transmission line consisting of two coupled segments which are identical in structure and different in parameters. The asymmetry of energy flux caused by nonlinear wave has been observed experimentally in the forbidden band of the line. The experiment shows whether the energy can flow through the transmission line depends on the amplitude of the boundary driving voltages, which can be well explained in the theoretical framework of nonlinear supratransmission. The numerical simulation based on Kirchhoff’s laws further verifies the existence of the asymmetric energy flux in the forbidden band.

  6. Role of the Band Gap for the Interaction Energy of Coadsorbed Fragments

    DEFF Research Database (Denmark)

    Castelli, Ivano Eligio; Man, Isabela-Costinela; Soriga, Stefan-Gabriel

    2017-01-01

    on semiconductors. We propose here a correlation between the cooperative interaction energy, i.e., the energy difference between the adsorption energies of coadsorbed electron donor–acceptor pair and isolated fragments and the band gap of the clean oxide surface. We demonstrate this effect for a number of oxides...... and donor–acceptor pairs and explain it with the shift in the Fermi level before and after the adsorption. The conclusion is that the adsorption of acceptor–donor pairs is considerably more favorable compared to unpaired fragments,and this energy difference is approximately equal to the value of the band...

  7. Improved cache performance in Monte Carlo transport calculations using energy banding

    Science.gov (United States)

    Siegel, A.; Smith, K.; Felker, K.; Romano, P.; Forget, B.; Beckman, P.

    2014-04-01

    We present an energy banding algorithm for Monte Carlo (MC) neutral particle transport simulations which depend on large cross section lookup tables. In MC codes, read-only cross section data tables are accessed frequently, exhibit poor locality, and are typically too much large to fit in fast memory. Thus, performance is often limited by long latencies to RAM, or by off-node communication latencies when the data footprint is very large and must be decomposed on a distributed memory machine. The proposed energy banding algorithm allows maximal temporal reuse of data in band sizes that can flexibly accommodate different architectural features. The energy banding algorithm is general and has a number of benefits compared to the traditional approach. In the present analysis we explore its potential to achieve improvements in time-to-solution on modern cache-based architectures.

  8. First-principles determination of band-to-band electronic transition energies in cubic and hexagonal AlGaInN alloys

    Directory of Open Access Journals (Sweden)

    F. L. Freitas

    2016-08-01

    Full Text Available We provide approximate quasiparticle-corrected band gap energies for quaternary cubic and hexagonal AlxGayIn1–x–yN semiconductor alloys, employing a cluster expansion method to account for the inherent statistical disorder of the system. Calculated values are compared with photoluminescence measurements and discussed within the currently accepted model of emission in these materials by carrier localization. It is shown that bowing parameters are larger in the cubic phase, while the range of band gap variation is bigger in the hexagonal one. Experimentally determined transition energies are mostly consistent with band-to-band excitations.

  9. First-principles determination of band-to-band electronic transition energies in cubic and hexagonal AlGaInN alloys

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, F. L., E-mail: felipelopesfreitas@gmail.com; Marques, M.; Teles, L. K. [Grupo de Materiais Semicondutores e Nanotecnologia, Instituto Tecnológico de Aeronáutica, 12228-900 São José dos Campos, SP (Brazil)

    2016-08-15

    We provide approximate quasiparticle-corrected band gap energies for quaternary cubic and hexagonal Al{sub x}Ga{sub y}In{sub 1–x–y}N semiconductor alloys, employing a cluster expansion method to account for the inherent statistical disorder of the system. Calculated values are compared with photoluminescence measurements and discussed within the currently accepted model of emission in these materials by carrier localization. It is shown that bowing parameters are larger in the cubic phase, while the range of band gap variation is bigger in the hexagonal one. Experimentally determined transition energies are mostly consistent with band-to-band excitations.

  10. Energy Impacts of Wide Band Gap Semiconductors in U.S. Light-Duty Electric Vehicle Fleet.

    Science.gov (United States)

    Warren, Joshua A; Riddle, Matthew E; Graziano, Diane J; Das, Sujit; Upadhyayula, Venkata K K; Masanet, Eric; Cresko, Joe

    2015-09-01

    Silicon carbide and gallium nitride, two leading wide band gap semiconductors with significant potential in electric vehicle power electronics, are examined from a life cycle energy perspective and compared with incumbent silicon in U.S. light-duty electric vehicle fleet. Cradle-to-gate, silicon carbide is estimated to require more than twice the energy as silicon. However, the magnitude of vehicle use phase fuel savings potential is comparatively several orders of magnitude higher than the marginal increase in cradle-to-gate energy. Gallium nitride cradle-to-gate energy requirements are estimated to be similar to silicon, with use phase savings potential similar to or exceeding that of silicon carbide. Potential energy reductions in the United States vehicle fleet are examined through several scenarios that consider the market adoption potential of electric vehicles themselves, as well as the market adoption potential of wide band gap semiconductors in electric vehicles. For the 2015-2050 time frame, cumulative energy savings associated with the deployment of wide band gap semiconductors are estimated to range from 2-20 billion GJ depending on market adoption dynamics.

  11. Esaki Diodes in van der Waals Heterojunctions with Broken-Gap Energy Band Alignment.

    Science.gov (United States)

    Yan, Rusen; Fathipour, Sara; Han, Yimo; Song, Bo; Xiao, Shudong; Li, Mingda; Ma, Nan; Protasenko, Vladimir; Muller, David A; Jena, Debdeep; Xing, Huili Grace

    2015-09-09

    van der Waals (vdW) heterojunctions composed of two-dimensional (2D) layered materials are emerging as a solid-state materials family that exhibits novel physics phenomena that can power a range of electronic and photonic applications. Here, we present the first demonstration of an important building block in vdW solids: room temperature Esaki tunnel diodes. The Esaki diodes were realized in vdW heterostructures made of black phosphorus (BP) and tin diselenide (SnSe2), two layered semiconductors that possess a broken-gap energy band offset. The presence of a thin insulating barrier between BP and SnSe2 enabled the observation of a prominent negative differential resistance (NDR) region in the forward-bias current-voltage characteristics, with a peak to valley ratio of 1.8 at 300 K and 2.8 at 80 K. A weak temperature dependence of the NDR indicates electron tunneling being the dominant transport mechanism, and a theoretical model shows excellent agreement with the experimental results. Furthermore, the broken-gap band alignment is confirmed by the junction photoresponse, and the phosphorus double planes in a single layer of BP are resolved in transmission electron microscopy (TEM) for the first time. Our results represent a significant advance in the fundamental understanding of vdW heterojunctions and broaden the potential applications of 2D layered materials.

  12. Primary transitions between the yrast superdeformed band and low-lying normal deformed states in {sup 194}Pb

    Energy Technology Data Exchange (ETDEWEB)

    Hauschild, K.; Bernstein, L.A.; Becker, J.A. [Lawrence Livermore National Lab., CA (United States)] [and others

    1996-12-31

    The observation of one-step `primary` gamma-ray transitions directly linking the superdeformed (SD) states to the normal deformed (ND) low-lying states of known excitation energies (E{sub x}), spins and parities (J{sup {pi}}) is crucial to determining the E{sub x} and J{sup {pi}} of the SD states. With this knowledge one can begin to address some of the outstanding problems associated with SD nuclei, such as the identical band issue, and one can also place more stringent restrictions on theoretical calculations which predict SD states and their properties. Brinkman, et al., used the early implementation of the GAMMASPHERE spectrometer array (32 detectors) and proposed a single, candidate {gamma} ray linking the {sup 194}Pb yrast SD band to the low-lying ND states in {sup 194}Pb. Using 55 detectors in the GAMMASPHERE array Khoo, et al., observed multiple links between the yrast SD band in {sup 194}Hg and the low-lying level scheme and conclusively determined E{sub x} and J of the yrast SD states. Here the authors report on an experiment in which Gammasphere with 88 detectors was used and the E{sub x} and J{sup {pi}} values of the yrast SD states in {sup 194}Pb were uniquely determined. Twelve one-step linking transitions between the yrast SD band and low-lying states in {sup 194}Pb have been identified, including the transition proposed by Brinkman. These transitions have been placed in the level scheme of {sup 194}Pb using coincidence relationships and agreements between the energies of the primary transitions and the energy differences in level spacings. Furthermore, measurements of angular asymmetries have yielded the multipolarities of the primaries which have allowed J{sup {pi}} assignments of the {sup 194}Pb SD states to be unambiguously determined for the first time without a priori assumptions about the character of SD bands. A study performed in parallel to this work using the EUROGAM-II array reports similar, but somewhat less extensive, results.

  13. Influence of energy bands on the Hall effect in degenerate semiconductors

    International Nuclear Information System (INIS)

    Wu, Chhi-Chong; Tsai, Jensan

    1989-01-01

    The influence of energy bands on the Hall effect and transverse magnetoresistance has been investigated according to the scattering processes of carriers in degenerate semiconductors such as InSb. Results show that the Hall angle, Hall coefficient, and transverse magnetoresistance depend on the dc magnetic field for both parabolic and nonparabolic band structures of semiconductors and also depend on the scattering processes of carriers in semiconductors due to the energy-dependent relaxation time. From their numerical analysis for the Hall effect, it is shown that the conduction electrons in degenerate semiconductors play a major role for the carrier transport phenomenon. By comparing with experimental data of the transverse magnetoresistance, it shows that the nonparabolic band model is better in agreement with the experimental work than the parabolic band model of semiconductors

  14. Fully inkjet printed wide band cantor fractal antenna for RF energy harvesting application

    KAUST Repository

    Bakytbekov, Azamat

    2017-06-07

    Energy harvesting from ambient RF signals is feasible, particularly from the GSM bands such as 900MHz, 1800MHz and the 3G band at 2.1GHz. This requires a wideband receive antenna which can cover all these bands with decent gain performance and an omnidirectional radiation pattern. In this work, a novel Cantor fractal antenna has been designed which fulfills the above mentioned performance requirements. Antenna has been realized through a combination of 3D inkjet printing of plastic substrate and 2D inkjet printing of metallic nanoparticles based ink. The stable impedance and radiation performance of the antenna over a bandwidth of 0.8GHz to 2.2GHz (93 %) shows the feasibility of its employment in wide band energy harvesting applications.

  15. State energy data report 1993: Consumption estimates

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    The State Energy Data Report (SEDR) provides annual time series estimates of State-level energy consumption by major economic sector. The estimates are developed in the State Energy Data System (SEDS), which is maintained and operated by the Energy Information Administration (EIA). The goal in maintaining SEDS is to create historical time series of energy consumption by State that are defined as consistently as possible over time and across sectors. SEDS exists for two principal reasons: (1) to provide State energy consumption estimates to Members of Congress, Federal and State agencies, and the general public; and (2) to provide the historical series necessary for EIA`s energy models.

  16. Symmetry conditions of a nodal superconductor for generating robust flat-band Andreev bound states at its dirty surface

    Science.gov (United States)

    Ikegaya, Satoshi; Kobayashi, Shingo; Asano, Yasuhiro

    2018-05-01

    We discuss the symmetry property of a nodal superconductor that hosts robust flat-band zero-energy states at its surface under potential disorder. Such robust zero-energy states are known to induce the anomalous proximity effect in a dirty normal metal attached to a superconductor. A recent study has shown that a topological index NZES describes the number of zero-energy states at the dirty surface of a p -wave superconductor. We generalize the theory to clarify the conditions required for a superconductor that enables NZES≠0 . Our results show that NZES≠0 is realized in a topological material that belongs to either the BDI or CII class. We also present two realistic Hamiltonians that result in NZES≠0 .

  17. State energy data report 1994: Consumption estimates

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    This document provides annual time series estimates of State-level energy consumption by major economic sector. The estimates are developed in the State Energy Data System (SEDS), operated by EIA. SEDS provides State energy consumption estimates to members of Congress, Federal and State agencies, and the general public, and provides the historical series needed for EIA`s energy models. Division is made for each energy type and end use sector. Nuclear electric power is included.

  18. State energy data report 1994: Consumption estimates

    International Nuclear Information System (INIS)

    1996-10-01

    This document provides annual time series estimates of State-level energy consumption by major economic sector. The estimates are developed in the State Energy Data System (SEDS), operated by EIA. SEDS provides State energy consumption estimates to members of Congress, Federal and State agencies, and the general public, and provides the historical series needed for EIA's energy models. Division is made for each energy type and end use sector. Nuclear electric power is included

  19. Band energy control of molybdenum oxide by surface hydration

    Energy Technology Data Exchange (ETDEWEB)

    Butler, Keith T., E-mail: k.t.butler@bath.ac.uk; Walsh, Aron [Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Crespo-Otero, Rachel [School of Biological and Chemical Sciences, Queen Mary University London, Mile End Road, London E1 4NS (United Kingdom); Buckeridge, John; Scanlon, David O. [University College London, Kathleen Lonsdale Materials Chemistry, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Bovill, Edward; Lidzey, David [Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

    2015-12-07

    The application of oxide buffer layers for improved carrier extraction is ubiquitous in organic electronics. However, the performance is highly susceptible to processing conditions. Notably, the interface stability and electronic structure is extremely sensitive to the uptake of ambient water. In this study we use density functional theory calculations to asses the effects of adsorbed water on the electronic structure of MoO{sub x}, in the context of polymer-fullerene solar cells based on PCDTBT. We obtain excellent agreement with experimental values of the ionization potential for pristine MoO{sub 3} (010). We find that IP and EA values can vary by as much as 2.5 eV depending on the oxidation state of the surface and that adsorbed water can either increase or decrease the IP and EA depending on the concentration of surface water.

  20. State Energy Data Report, 1991: Consumption estimates

    International Nuclear Information System (INIS)

    1993-05-01

    The State Energy Data Report (SEDR) provides annual time series estimates of State-level energy consumption by major economic sector. The estimates are developed in the State Energy Data System (SEDS), which is maintained and operated by the Energy Information Administration (EIA). The goal in maintaining SEDS is to create historical time series of energy consumption by State that are defined as consistently as possible over time and across sectors. SEDS exists for two principal reasons: (1) to provide State energy consumption estimates to the Government, policy makers, and the public; and (2) to provide the historical series necessary for EIA's energy models

  1. Spectroscopy of 9Be and observation of neutron halo structure in the states of positive parity rotational band

    Directory of Open Access Journals (Sweden)

    Demyanova A.S.

    2014-03-01

    Full Text Available The differential cross sections of the 9Be + α inelastic scattering at 30 MeV were measured at the tandem of Tsukuba University. All the known states of 9Be up to energies ~ 12 MeV were observed and decomposed into three rotational bands, each of them having a cluster structure consisting of a 8Be core plus a valence neutron in one of the sub-shells: p3/2−, s1/2+ and p1/2−. Existence of a neutron halo in the positive parity states was confirmed.

  2. Modeling and analysis of renewable energy obligations and technology bandings in the UK electricity market

    International Nuclear Information System (INIS)

    Gürkan, Gül; Langestraat, Romeo

    2014-01-01

    In the UK electricity market, generators are obliged to produce part of their electricity with renewable energy resources in accordance with the Renewable Obligation Order. Since 2009 technology banding has been added, meaning that different technologies are rewarded with a different number of certificates. We analyze these two different renewable obligation policies in a mathematical representation of an electricity market with random availabilities of renewable generation outputs and random electricity demand. We also present another, alternative, banding policy. We provide revenue adequate pricing schemes for the three obligation policies. We carry out a simulation study via sampling. A key finding is that the UK banding policy cannot guarantee that the original obligation target is met, hence potentially resulting in more pollution. Our alternative provides a way to make sure that the target is met while supporting less established technologies, but it comes with a significantly higher consumer price. Furthermore, as an undesirable side effect, we observe that a cost reduction in a technology with a high banding (namely offshore wind) leads to more CO 2 emissions under the UK banding policy and to higher consumer prices under the alternative banding policy. - Highlights: • We model and analyze three renewable obligation policies in a mathematical framework. • We provide revenue adequate pricing schemes for the three policies. • We carry out a simulation study via sampling. • The UK policy cannot guarantee that the original obligation target is met. • Cost reductions can lead to more pollution or higher prices under banding policies

  3. Effect of Γ-X band mixing on the donor binding energy in a Quantum Wire

    Science.gov (United States)

    Vijaya Shanthi, R.; Jayakumar, K.; Nithiananthi, P.

    2015-02-01

    To invoke the technological applications of heterostructure semiconductors like Quantum Well (QW), Quantum Well Wire (QWW) and Quantum Dot (QD), it is important to understand the property of impurity energy which is responsible for the peculiar electronic & optical behavior of the Low Dimensional Semiconductor Systems (LDSS). Application of hydrostatic pressure P>35kbar drastically alters the band offsets leading to the crossover of Γ band of the well & X band of the barrier resulting in an indirect transition of the carrier and this effect has been studied experimentally and theoretically in a QW structure. In this paper, we have investigated the effect of Γ-X band mixing due to the application of hydrostatic pressure in a GaAs/AlxGa1-xAs QWW system. The results are presented and discussed for various widths of the wire.

  4. Strategic Energy Management Plan for the Santa Ynez Band of Chumash Indians

    Energy Technology Data Exchange (ETDEWEB)

    Davenport, Lars [Santa Ynez Band of Chumash Indians, Santa Ynez, CA (United States); Smythe, Louisa [Santa Ynez Band of Chumash Indians, Santa Ynez, CA (United States); Sarquilla, Lindsey [Santa Ynez Band of Chumash Indians, Santa Ynez, CA (United States); Ferguson, Kelly [Santa Ynez Band of Chumash Indians, Santa Ynez, CA (United States)

    2015-03-27

    This plan outlines the Santa Ynez Band of Chumash Indians’ comprehensive energy management strategy including an assessment of current practices, a commitment to improving energy performance and reducing overall energy use, and recommended actions to achieve these goals. Vision Statement The primary objective of the Strategic Energy Management Plan is to implement energy efficiency, energy security, conservation, education, and renewable energy projects that align with the economic goals and cultural values of the community to improve the health and welfare of the tribe. The intended outcomes of implementing the energy plan include job creation, capacity building, and reduced energy costs for tribal community members, and tribal operations. By encouraging energy independence and local power production the plan will promote self-sufficiency. Mission & Objectives The Strategic Energy Plan will provide information and suggestions to guide tribal decision-making and provide a foundation for effective management of energy resources within the Santa Ynez Band of Chumash Indians (SYBCI) community. The objectives of developing this plan include; Assess current energy demand and costs of all tribal enterprises, offices, and facilities; Provide a baseline assessment of the SYBCI’s energy resources so that future progress can be clearly and consistently measured, and current usage better understood; Project future energy demand; Establish a system for centralized, ongoing tracking and analysis of tribal energy data that is applicable across sectors, facilities, and activities; Develop a unifying vision that is consistent with the tribe’s long-term cultural, social, environmental, and economic goals; Identify and evaluate the potential of opportunities for development of long-term, cost effective energy sources, such as renewable energy, energy efficiency and conservation, and other feasible supply- and demand-side options; and Build the SYBCI’s capacity for

  5. Emerging Energy Alternatives for the Southeastern States

    Science.gov (United States)

    Stefanakos, E. K. (Editor)

    1978-01-01

    The proceedings of the first symposium on emerging energy alternatives for the Southeastern States are presented. Some topics discussed are: (1) solar energy, (2) wood energy, (3) novel energy sources, (4) agricultural and industrial process heat, (5) waste utilization, (6) energy conservation and (7) ocean thermal energy conversion.

  6. State energy data report 1995 - consumption estimates

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    The State Energy Data Report (SEDR) provides annual time series estimates of State-level energy consumption by major economic sectors. The estimates are developed in the State Energy Data System (SEDS), which is maintained and operated by the Energy Information Administration (EIA). The goal in maintaining SEDS exists for two principal reasons: (1) to provide State energy consumption estimates to Members of Congress, Federal and State agencies, and the general public, and (2) to provide the historical series necessary for EIA`s energy models.

  7. State Energy Efficiency Benefits and Opportunities

    Science.gov (United States)

    Describes the benefits of energy efficiency and how to assess its potential for your state. Also, find details on energy efficiency policies, programs, and resources available for furthering energy efficiency goals.

  8. The State and atomic energy

    International Nuclear Information System (INIS)

    Jungk, R.

    1991-01-01

    Illustrous, eloquent, and yet easy to read for the interested layman, the book begins with alleged deplorable conditions at the reprocessing centra La Hague, portrays, amongst other things, the spying on and supervision of persons in the nuclear field and in research, the misuse of fissile material, and threats and blackmail as a consequence thereof, human error as a cause of accidents, and it concludes with a nonviolent new International against the state and atomic energy, against technological tyranny. Titles of chapters: The hard road; radiation feed; the gamblers; homo atomicus; the intimidated; the ''proliferators''; nuclear terrorists; those supervised; the smooth road. It remains an open question whether the book contributes to defusing the nuclear controversy - in the book almost an ideology - and to bringing the two sides closer together. (HP) [de

  9. Temperature Dependence of the Energy Band Diagram of AlGaN/GaN Heterostructure

    Directory of Open Access Journals (Sweden)

    Yanli Liu

    2018-01-01

    Full Text Available Temperature dependence of the energy band diagram of AlGaN/GaN heterostructure was investigated by theoretical calculation and experiment. Through solving Schrodinger and Poisson equations self-consistently by using the Silvaco Atlas software, the energy band diagram with varying temperature was calculated. The results indicate that the conduction band offset of AlGaN/GaN heterostructure decreases with increasing temperature in the range of 7 K to 200 K, which means that the depth of quantum well at AlGaN/GaN interface becomes shallower and the confinement of that on two-dimensional electron gas reduces. The theoretical calculation results are verified by the investigation of temperature dependent photoluminescence of AlGaN/GaN heterostructure. This work provides important theoretical and experimental basis for the performance degradation of AlGaN/GaN HEMT with increasing temperature.

  10. Accurate Energy Consumption Modeling of IEEE 802.15.4e TSCH Using Dual-BandOpenMote Hardware.

    Science.gov (United States)

    Daneels, Glenn; Municio, Esteban; Van de Velde, Bruno; Ergeerts, Glenn; Weyn, Maarten; Latré, Steven; Famaey, Jeroen

    2018-02-02

    The Time-Slotted Channel Hopping (TSCH) mode of the IEEE 802.15.4e amendment aims to improve reliability and energy efficiency in industrial and other challenging Internet-of-Things (IoT) environments. This paper presents an accurate and up-to-date energy consumption model for devices using this IEEE 802.15.4e TSCH mode. The model identifies all network-related CPU and radio state changes, thus providing a precise representation of the device behavior and an accurate prediction of its energy consumption. Moreover, energy measurements were performed with a dual-band OpenMote device, running the OpenWSN firmware. This allows the model to be used for devices using 2.4 GHz, as well as 868 MHz. Using these measurements, several network simulations were conducted to observe the TSCH energy consumption effects in end-to-end communication for both frequency bands. Experimental verification of the model shows that it accurately models the consumption for all possible packet sizes and that the calculated consumption on average differs less than 3% from the measured consumption. This deviation includes measurement inaccuracies and the variations of the guard time. As such, the proposed model is very suitable for accurate energy consumption modeling of TSCH networks.

  11. State energy data report 1996: Consumption estimates

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-02-01

    The State Energy Data Report (SEDR) provides annual time series estimates of State-level energy consumption by major economic sectors. The estimates are developed in the Combined State Energy Data System (CSEDS), which is maintained and operated by the Energy Information Administration (EIA). The goal in maintaining CSEDS is to create historical time series of energy consumption by State that are defined as consistently as possible over time and across sectors. CSEDS exists for two principal reasons: (1) to provide State energy consumption estimates to Members of Congress, Federal and State agencies, and the general public and (2) to provide the historical series necessary for EIA`s energy models. To the degree possible, energy consumption has been assigned to five sectors: residential, commercial, industrial, transportation, and electric utility sectors. Fuels covered are coal, natural gas, petroleum, nuclear electric power, hydroelectric power, biomass, and other, defined as electric power generated from geothermal, wind, photovoltaic, and solar thermal energy. 322 tabs.

  12. State energy data report 1996: Consumption estimates

    International Nuclear Information System (INIS)

    1999-02-01

    The State Energy Data Report (SEDR) provides annual time series estimates of State-level energy consumption by major economic sectors. The estimates are developed in the Combined State Energy Data System (CSEDS), which is maintained and operated by the Energy Information Administration (EIA). The goal in maintaining CSEDS is to create historical time series of energy consumption by State that are defined as consistently as possible over time and across sectors. CSEDS exists for two principal reasons: (1) to provide State energy consumption estimates to Members of Congress, Federal and State agencies, and the general public and (2) to provide the historical series necessary for EIA's energy models. To the degree possible, energy consumption has been assigned to five sectors: residential, commercial, industrial, transportation, and electric utility sectors. Fuels covered are coal, natural gas, petroleum, nuclear electric power, hydroelectric power, biomass, and other, defined as electric power generated from geothermal, wind, photovoltaic, and solar thermal energy. 322 tabs

  13. Modeling and analysis of renewable energy obligations and technology bandings in the UK electricity market

    NARCIS (Netherlands)

    Gurkan, G.; Langestraat, R.

    In the UK electricity market, generators are obliged to produce part of their electricity with renewable energy resources in accordance with the Renewable Obligation Order. Since 2009 technology banding has been added, meaning that different technologies are rewarded with a different number of

  14. Valence band structure and density of states effective mass model of biaxial tensile strained silicon based on k · p theory

    International Nuclear Information System (INIS)

    Kuang Qian-Wei; Liu Hong-Xia; Wang Shu-Long; Qin Shan-Shan; Wang Zhi-Lin

    2011-01-01

    After constructing a stress and strain model, the valence bands of in-plane biaxial tensile strained Si is calculated by k · p method. In the paper we calculate the accurate anisotropy valance bands and the splitting energy between light and heavy hole bands. The results show that the valance bands are highly distorted, and the anisotropy is more obvious. To obtain the density of states (DOS) effective mass, which is a very important parameter for device modeling, a DOS effective mass model of biaxial tensile strained Si is constructed based on the valance band calculation. This model can be directly used in the device model of metal—oxide semiconductor field effect transistor (MOSFET). It also a provides valuable reference for biaxial tensile strained silicon MOSFET design. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  15. CdSe/CdTe interface band gaps and band offsets calculated using spin-orbit and self-energy corrections

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, M. [Centro de Pesquisas Avancadas Wernher von Braun, Av. Alice de Castro P.N. Mattosinho 301, CEP 13098-392 Campinas, SP (Brazil); Ferreira, L.G. [Departamento de Fisica dos Materiais e Mecanica, Instituto de Fisica, Universidade de Sao Paulo, 05315-970 Sao Paulo, SP (Brazil); Fonseca, L.R.C. [Center for Semiconductor Components, State University of Campinas, R. Pandia Calogeras 90, 13083-870 Campinas, SP (Brazil); Ramprasad, R. [Department of Chemical, Materials and Biomolecular Engineering, Institute of Materials Science, University of Connecticut, 97 North Eagleville Road, Storrs, CT 06269 (United States)

    2012-09-20

    We performed ab initio calculations of the electronic structures of bulk CdSe and CdTe, and their interface band alignments on the CdSe in-plane lattice parameters. For this, we employed the LDA-1/2 self-energy correction scheme to obtain corrected band gaps and band offsets. Our calculations include the spin-orbit effects for the bulk cases, which have shown to be of importance for the equilibrium systems and are possibly degraded in these strained semiconductors. Therefore, the SO showed reduced importance for the band alignment of this particular system. Moreover, the electronic structure calculated along the transition region across the CdSe/CdTe interface shows an interesting non-monotonic variation of the band gap in the range 0.8-1.8 eV, which may enhance the absorption of light for corresponding frequencies at the interface between these two materials in photovoltaic applications.

  16. New high spin states and band termination in 83Y and 84Zr

    International Nuclear Information System (INIS)

    Johnson, T.D.; Aprahamian, A.; Lister, C.J.; Blumenthal, D.J.; Crowell, B.; Chowdhury, P.; Fallon, P.; Machiavelli, A.O.

    1997-01-01

    The gamma decay of high spin yrast states in 83 Y up to I π =59/2 + and 53/2 - have been observed using the reaction 58 Ni( 29 Si,3p) at 110 MeV and the Gammasphere Early Implementation Array. The level scheme has been substantially extended due to the observations of several new transitions in all of the bands. A sequence of transitions feeding into the positive parity yrast band above I π =47/2 + seems to be consistent with a noncollective oblate structure expected at these high spins. A similar cascade is found in the data for 84 Zr. A new forking of the favored negative parity band is found which may be due to neutron alignment polarizing the core to a different shape. This suggests that the open-quotes isomeric close-quote close-quote band in 83 Y, for which one more connecting transition was found, is of a similar nature to other high-K bands found in this region. Lifetime measurements in the unfavored negative parity band are consistent with cranking calculations which predict a nearly oblate shape with a deformation parameter β 2 ∼0.2. A qualitative analysis of line shapes at very high spins suggests the persistence of collectivity in the yrast sequence to the highest excitations seen. copyright 1997 The American Physical Society

  17. New high spin states and band termination in {sup 83}Y and {sup 84}Zr

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, T.D.; Aprahamian, A. [University of Notre Dame, Notre Dame, Indiana 46556 (United States); Lister, C.J.; Blumenthal, D.J.; Crowell, B. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Chowdhury, P. [University of Massachusetts, Lowell, Massachusetts 01854 (United States); Fallon, P.; Machiavelli, A.O. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    1997-03-01

    The gamma decay of high spin yrast states in {sup 83}Y up to I{sup {pi}}=59/2{sup +} and 53/2{sup {minus}} have been observed using the reaction {sup 58}Ni({sup 29}Si,3p) at 110 MeV and the Gammasphere Early Implementation Array. The level scheme has been substantially extended due to the observations of several new transitions in all of the bands. A sequence of transitions feeding into the positive parity yrast band above I{sup {pi}}=47/2{sup +} seems to be consistent with a noncollective oblate structure expected at these high spins. A similar cascade is found in the data for {sup 84}Zr. A new forking of the favored negative parity band is found which may be due to neutron alignment polarizing the core to a different shape. This suggests that the {open_quotes}isomeric{close_quote}{close_quote} band in {sup 83}Y, for which one more connecting transition was found, is of a similar nature to other high-K bands found in this region. Lifetime measurements in the unfavored negative parity band are consistent with cranking calculations which predict a nearly oblate shape with a deformation parameter {beta}{sub 2}{approx}0.2. A qualitative analysis of line shapes at very high spins suggests the persistence of collectivity in the yrast sequence to the highest excitations seen. {copyright} {ital 1997} {ital The American Physical Society}

  18. 10. State energy balance - 1978-1991

    International Nuclear Information System (INIS)

    1993-12-01

    The energetic matrix of Minas Gerais State (Brazil) for the year 1991 and historic review of 1978 to 1990 are shown in this 10. State Energy Balance. The global balance and the state structure of energy demand, by energy source and socio-economic sector are presented, and the relations between energy system and the Minas Gerais economic performance are analysed. The consumption evolution by sector is also cited. (C.G.C.)

  19. Energy band structure of Cr by the Slater-Koster interpolation scheme

    International Nuclear Information System (INIS)

    Seifu, D.; Mikusik, P.

    1986-04-01

    The matrix elements of the Hamiltonian between nine localized wave-functions in tight-binding formalism are derived. The symmetry adapted wave-functions and the secular equations are formed by the group theory method for high symmetry points in the Brillouin zone. A set of interaction integrals is chosen on physical ground and fitted via the Slater-Koster interpolation scheme to the abinito band structure of chromium calculated by the Green function method. Then the energy band structure of chromium is interpolated and extrapolated in the Brillouin zone. (author)

  20. Transparent Conducting Oxides for Photovoltaics: Manipulation of Fermi Level, Work Function and Energy Band Alignment

    Directory of Open Access Journals (Sweden)

    Diana E. Proffit

    2010-11-01

    Full Text Available Doping limits, band gaps, work functions and energy band alignments of undoped and donor-doped transparent conducting oxides Zn0, In2O3, and SnO2 as accessed by X-ray and ultraviolet photoelectron spectroscopy (XPS/UPS are summarized and compared. The presented collection provides an extensive data set of technologically relevant electronic properties of photovoltaic transparent electrode materials and illustrates how these relate to the underlying defect chemistry, the dependence of surface dipoles on crystallographic orientation and/or surface termination, and Fermi level pinning.

  1. Lanthanide 4f-electron binding energies and the nephelauxetic effect in wide band gap compounds

    International Nuclear Information System (INIS)

    Dorenbos, Pieter

    2013-01-01

    Employing data from luminescence spectroscopy, the inter 4f-electron Coulomb repulsion energy U(6, A) in Eu 2+/3+ impurities together with the 5d-centroid energy shift ϵ c (1,3+,A) in Ce 3+ impurities in 40 different fluoride, chloride, bromide, iodide, oxide, sulfide, and nitride compounds has been determined. This work demonstrates that the chemical environment A affects the two energies in a similar fashion; a fashion that follows the anion nephelauxetic sequence F, O, Cl, Br, N, I, S, Se. One may then calculate U(6, A) from well established and accurate ϵ c (1,3+,A) values which are then used as input to the chemical shift model proposed in Dorenbos (2012) [19]. As output it provides the chemical shift of 4f-electron binding energy and therewith the 4f-electron binding energy relative to the vacuum energy. In addition this method provides a tool to routinely establish the binding energy of electrons at the top of the valence band (work function) and the bottom of the conduction band (electron affinity) throughout the entire family of inorganic compounds. How the electronic structure of the compound and lanthanide impurities therein change with type of compound and type of lanthanide is demonstrated. -- Highlights: ► A relationship between 5d centroid shift and 4f-electron Coulomb repulsion energy is established. ► Information on the absolute 4f-electron binding energy of lanthanides in 40 compounds is provided. ► A new tool to determine absolute binding energies of electrons in valence and conduction bands is demonstrated

  2. State energy price and expenditure report 1990

    International Nuclear Information System (INIS)

    1992-01-01

    The State Energy Price and Expenditure Report (SEPER) presents energy price and expenditure estimates individually for the 50 States and the District of Columbia and in aggregate for the United States. The estimates are provided by energy source and economic sector. This report is an update of the State Energy Price and Expenditure Report 1989 published in September 1991. Energy price and expenditure estimates are published for the years 1970, 1975, 1980, and 1985 through 1990. Documentation follows the tables and describes how the price estimates are developed, including sources of data, methods of estimation, and conversion factors applied

  3. Search for two-{gamma} sum-energy peaks in the decay out of superdeformed bands

    Energy Technology Data Exchange (ETDEWEB)

    Blumenthal, D.; Khoo, T.L.; Lauritsen, T. [and others

    1995-08-01

    The spectrum of {gamma}rays decaying out of the superdeformed (SD) band in {sup 192}Hg has a quasicontinuous distribution. Whereas methods to construct level schemes from discrete lines in coincidence spectra are well established, new techniques must still be developed to extract information from coincidences involving quasicontinuous {gamma}rays. From an experiment using Eurogam, we obtained impressively clean 1- and 2-dimensional {gamma} spectra from pairwise or single gates, respectively, on the transitions of the SD band in {sup 192}Hg. We investigated methods to exploit the 2-dimensional quasicontinuum spectra coincident with the SD band to determine the excitation energy of the SD band above the normal yrast line. No strong peaks were observed in the 2-{gamma} sum spectra; only candidates of peaks at a 2-3 {sigma} level were found. This suggests that 2-{gamma} decay is not the dominant decay branch out of SD bands, consistent with the observed multiplicity of 3.2. We shall next search for peaks in sum-spectra of 3 {gamma}s.

  4. Resting-state theta-band connectivity and verbal memory in schizophrenia and in the high-risk state.

    Science.gov (United States)

    Andreou, Christina; Leicht, Gregor; Nolte, Guido; Polomac, Nenad; Moritz, Steffen; Karow, Anne; Hanganu-Opatz, Ileana L; Engel, Andreas K; Mulert, Christoph

    2015-02-01

    Disturbed functional connectivity is assumed to underlie neurocognitive deficits in patients with schizophrenia. As neurocognitive deficits are already present in the high-risk state, identification of the neural networks involved in this core feature of schizophrenia is essential to our understanding of the disorder. Resting-state studies enable such investigations, while at the same time avoiding the known confounder of impaired task performance in patients. The aim of the present study was to investigate EEG resting-state connectivity in high-risk individuals (HR) compared to first episode patients with schizophrenia (SZ) and to healthy controls (HC), and its association with cognitive deficits. 64-channel resting-state EEG recordings (eyes closed) were obtained for 28 HR, 19 stable SZ, and 23 HC, matched for age, education, and parental education. The imaginary coherence-based multivariate interaction measure (MIM) was used as a measure of connectivity across 80 cortical regions and six frequency bands. Mean connectivity at each region was compared across groups using the non-parametric randomization approach. Additionally, the network-based statistic was applied to identify affected networks in patients. SZ displayed increased theta-band resting-state MIM connectivity across midline, sensorimotor, orbitofrontal regions and the left temporoparietal junction. HR displayed intermediate theta-band connectivity patterns that did not differ from either SZ or HC. Mean theta-band connectivity within the above network partially mediated verbal memory deficits in SZ and HR. Aberrant theta-band connectivity may represent a trait characteristic of schizophrenia associated with neurocognitive deficits. As such, it might constitute a promising target for novel treatment applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge

    Energy Technology Data Exchange (ETDEWEB)

    Inaoka, Takeshi, E-mail: inaoka@phys.u-ryukyu.ac.jp; Furukawa, Takuro; Toma, Ryo; Yanagisawa, Susumu [Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213 (Japan)

    2015-09-14

    By means of a hybrid density-functional method, we investigate the tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge. We consider [001], [111], and [110] uniaxial tensility and (001), (111), and (110) biaxial tensility. Under the condition of no normal stress, we determine both normal compression and internal strain, namely, relative displacement of two atoms in the primitive unit cell, by minimizing the total energy. We identify those strain types which can induce the band-gap transition, and evaluate the critical strain coefficient where the gap transition occurs. Either normal compression or internal strain operates unfavorably to induce the gap transition, which raises the critical strain coefficient or even blocks the transition. We also examine how each type of tensile strain decreases the band-gap energy, depending on its orientation. Our analysis clearly shows that synergistic operation of strain orientation and band anisotropy has a great influence on the gap transition and the gap energy.

  6. Effect of density of state on isotope effect exponent of two-band superconductors

    International Nuclear Information System (INIS)

    Udomsamuthirun, P.; Kumvongsa, C.; Burakorn, A.; Changkanarth, P.; Yoksan, S.

    2005-01-01

    The exact formula of T c 's equation and the isotope effect exponent of two-band s-wave superconductors in weak-coupling limit are derived by considering the influence of two kinds of density of state: constant and van Hove singularity. The paring interaction in each band consisted of two parts: the electron-phonon interaction and non-electron-phonon interaction are included in our model. We find that the interband interaction of electron-phonon show more effect on isotope exponent than the intraband interaction and the isotope effect exponent with constant density of state can fit to experimental data, MgB 2 and high-T c superconductor, better than van Hove singularity density of state

  7. State-Level Benefits of Energy Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Tonn, Bruce Edward [ORNL

    2007-02-01

    This report describes benefits attributable to state-level energy efficiency programs. Nationwide, state-level energy efficiency programs have targeted all sectors of the economy and have employed a wide range of methods to promote energy efficiency. Standard residential and industrial programs typically identify between 20 to 30% energy savings in homes and plants, respectively. Over a 20 year period of time, an average state that aggressively pursues even a limited array of energy efficiency programs can potentially reduce total state energy use by as much as 20%. Benefit-cost ratios of effective energy efficiency programs typically exceed 3 to 1 and are much higher when non-energy and macroeconomic benefits are included. Indeed, energy efficiency and associated programs and investments can create significant numbers of new jobs and enhance state tax revenues. Several states have incorporated energy efficiency into their economic development programs. It should also be noted that increasing amounts of venture capital are being invested in the energy sector in general and in specific technologies like solar power in particular. Well-designed energy efficiency programs can be expected to help overcome numerous barriers to the market penetration of energy efficient technologies and accelerate the market penetration of the technologies.

  8. State-level benefits of energy efficiency

    International Nuclear Information System (INIS)

    Tonn, Bruce; Peretz, Jean H.

    2007-01-01

    This paper describes benefits attributable to state-level energy efficiency programs. Nationwide, state-level energy efficiency programs have targeted all sectors of the economy and have employed a wide range of methods to promote energy efficiency. Standard residential and industrial programs typically identify between 20% and 30% energy savings in homes and plants, respectively. Over a 20-year period of time, an average state that aggressively pursues even a limited array of energy efficiency programs can potentially reduce total state energy use by as much as 20%. Well-designed energy efficiency programs can be expected to help overcome numerous barriers to the market penetration of energy efficient technologies and accelerate the market penetration of the technologies. Energy efficiency programs are cost-effective; typical benefit-cost ratios exceed 3:1 and are much higher when non-energy and macroeconomic benefits are included. Indeed, energy efficiency and associated programs and investments can create significant numbers of new jobs and enhance state tax revenues. Several states have incorporated energy efficiency into their economic development programs. It should also be noted that increasing amounts of venture capital are being invested in the energy sector in general and in specific technologies like solar power in particular. (author)

  9. Relocation of the disulfonic stilbene sites of AE1 (band 3) on the basis of fluorescence energy transfer measurements.

    Science.gov (United States)

    Knauf, Philip A; Law, Foon-Yee; Leung, Tze-Wah Vivian; Atherton, Stephen J

    2004-09-28

    Previous fluorescence resonance energy transfer (FRET) measurements, using BIDS (4-benzamido-4'-isothiocyanostilbene-2,2'-disulfonate) as a label for the disulfonic stilbene site and FM (fluorescein-5-maleimide) as a label for the cytoplasmic SH groups on band 3 (AE1), combined with data showing that the cytoplasmic SH groups lie about 40 A from the cytoplasmic surface of the lipid bilayer, would place the BIDS sites very near the membrane's inner surface, a location that seems to be inconsistent with current models of AE1 structure and mechanism. We reinvestigated the BIDS-FM distance, using laser single photon counting techniques as well as steady-state fluorescence of AE1, in its native membrane environment. Both techniques agree that there is very little energy transfer from BIDS to FM. The mean energy transfer (E), based on three-exponential fits to the fluorescence decay data, is 2.5 +/- 0.7% (SEM, N = 12). Steady-state fluorescence measurements also indicate BIDS to FM. These data indicate that the BIDS sites are probably over 63 A from the cytoplasmic SH groups, placing them near the middle or the external half of the lipid bilayer. This relocation of the BIDS sites fits with other evidence that the disulfonic stilbene sites are located farther toward the external membrane surface than Glu-681, a residue near the inner membrane surface whose modification affects the pH dependence and anion selectivity of band 3. The involvement of two relatively distant parts of the AE1 protein in transport function suggests that the transport mechanism requires coordinated large-scale conformational changes in the band 3 protein.

  10. State energy data report 1992: Consumption estimates

    Energy Technology Data Exchange (ETDEWEB)

    1994-05-01

    This is a report of energy consumption by state for the years 1960 to 1992. The report contains summaries of energy consumption for the US and by state, consumption by source, comparisons to other energy use reports, consumption by energy use sector, and describes the estimation methodologies used in the preparation of the report. Some years are not listed specifically although they are included in the summary of data.

  11. Quantitative operando visualization of the energy band depth profile in solar cells.

    Science.gov (United States)

    Chen, Qi; Mao, Lin; Li, Yaowen; Kong, Tao; Wu, Na; Ma, Changqi; Bai, Sai; Jin, Yizheng; Wu, Dan; Lu, Wei; Wang, Bing; Chen, Liwei

    2015-07-13

    The energy band alignment in solar cell devices is critically important because it largely governs elementary photovoltaic processes, such as the generation, separation, transport, recombination and collection of charge carriers. Despite the expenditure of considerable effort, the measurement of energy band depth profiles across multiple layers has been extremely challenging, especially for operando devices. Here we present direct visualization of the surface potential depth profile over the cross-sections of operando organic photovoltaic devices using scanning Kelvin probe microscopy. The convolution effect due to finite tip size and cantilever beam crosstalk has previously prohibited quantitative interpretation of scanning Kelvin probe microscopy-measured surface potential depth profiles. We develop a bias voltage-compensation method to address this critical problem and obtain quantitatively accurate measurements of the open-circuit voltage, built-in potential and electrode potential difference.

  12. High Energy Solid State Laser Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — A suite of laboratories with advanced spectroscopic and laser equipment, this facility develops materials and techniques for advanced solid state high energy lasers....

  13. Helical quantum states in HgTe quantum dots with inverted band structures.

    Science.gov (United States)

    Chang, Kai; Lou, Wen-Kai

    2011-05-20

    We investigate theoretically the electron states in HgTe quantum dots (QDs) with inverted band structures. In sharp contrast to conventional semiconductor quantum dots, the quantum states in the gap of the HgTe QD are fully spin-polarized and show ringlike density distributions near the boundary of the QD and spin-angular momentum locking. The persistent charge currents and magnetic moments, i.e., the Aharonov-Bohm effect, can be observed in such a QD structure. This feature offers us a practical way to detect these exotic ringlike edge states by using the SQUID technique.

  14. Augustine Band of Cahuilla Indians Energy Conservation and Options Analysis - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Paul Turner

    2008-07-11

    The Augustine Band of Cahuilla Indians was awarded a grant through the Department of Energy First Steps program in June of 2006. The primary purpose of the grant was to enable the Tribe to develop energy conservation policies and a strategy for alternative energy resource development. All of the work contemplated by the grant agreement has been completed and the Tribe has begun implementing the resource development strategy through the construction of a 1.0 MW grid-connected photovoltaic system designed to offset a portion of the energy demand generated by current and projected land uses on the Tribe’s Reservation. Implementation of proposed energy conservation policies will proceed more deliberately as the Tribe acquires economic development experience sufficient to evaluate more systematically the interrelationships between conservation and its economic development goals.

  15. Energy Metrics for State Government Buildings

    Science.gov (United States)

    Michael, Trevor

    Measuring true progress towards energy conservation goals requires the accurate reporting and accounting of energy consumption. An accurate energy metrics framework is also a critical element for verifiable Greenhouse Gas Inventories. Energy conservation in government can reduce expenditures on energy costs leaving more funds available for public services. In addition to monetary savings, conserving energy can help to promote energy security, air quality, and a reduction of carbon footprint. With energy consumption/GHG inventories recently produced at the Federal level, state and local governments are beginning to also produce their own energy metrics systems. In recent years, many states have passed laws and executive orders which require their agencies to reduce energy consumption. In June 2008, SC state government established a law to achieve a 20% energy usage reduction in state buildings by 2020. This study examines case studies from other states who have established similar goals to uncover the methods used to establish an energy metrics system. Direct energy consumption in state government primarily comes from buildings and mobile sources. This study will focus exclusively on measuring energy consumption in state buildings. The case studies reveal that many states including SC are having issues gathering the data needed to accurately measure energy consumption across all state buildings. Common problems found include a lack of enforcement and incentives that encourage state agencies to participate in any reporting system. The case studies are aimed at finding the leverage used to gather the needed data. The various approaches at coercing participation will hopefully reveal methods that SC can use to establish the accurate metrics system needed to measure progress towards its 20% by 2020 energy reduction goal. Among the strongest incentives found in the case studies is the potential for monetary savings through energy efficiency. Framing energy conservation

  16. State energy price and expenditure report 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-01

    The State Energy Price and Expenditure Report (SEPER) presents energy price and expenditure estimates individually for the 50 States and the District of Columbia and in aggregate for the United States. The price and expenditure estimates developed in the State Energy Price and Expenditure Data System (SEPEDS) are provided by energy source and economic sector and are published for the years 1970 through 1994. Consumption estimates used to calculate expenditures and the documentation for those estimates are taken from the State Energy Data Report 1994, Consumption Estimates (SEDR), published in October 1996. Expenditures are calculated by multiplying the price estimates by the consumption estimates, which are adjusted to remove process fuel; intermediate petroleum products; and other consumption that has no direct fuel costs, i.e., hydroelectric, geothermal, wind, solar, and photovoltaic energy sources. Documentation is included describing the development of price estimates, data sources, and calculation methods. 316 tabs.

  17. State energy price and expenditure report 1994

    International Nuclear Information System (INIS)

    1997-06-01

    The State Energy Price and Expenditure Report (SEPER) presents energy price and expenditure estimates individually for the 50 States and the District of Columbia and in aggregate for the United States. The price and expenditure estimates developed in the State Energy Price and Expenditure Data System (SEPEDS) are provided by energy source and economic sector and are published for the years 1970 through 1994. Consumption estimates used to calculate expenditures and the documentation for those estimates are taken from the State Energy Data Report 1994, Consumption Estimates (SEDR), published in October 1996. Expenditures are calculated by multiplying the price estimates by the consumption estimates, which are adjusted to remove process fuel; intermediate petroleum products; and other consumption that has no direct fuel costs, i.e., hydroelectric, geothermal, wind, solar, and photovoltaic energy sources. Documentation is included describing the development of price estimates, data sources, and calculation methods. 316 tabs

  18. Statistics of anomalously localized states at the center of band E = 0 in the one-dimensional Anderson localization model

    International Nuclear Information System (INIS)

    Kravtsov, V E; Yudson, V I

    2013-01-01

    We consider the distribution function P(|ψ| 2 ) of the eigenfunction amplitude at the center-of-band (E = 0) anomaly in the one-dimensional tight-binding chain with weak uncorrelated on-site disorder (the one-dimensional Anderson model). The special emphasis is on the probability of the anomalously localized states (ALS) with |ψ| 2 much larger than the inverse typical localization length ℓ 0 . Using the recently found solution for the generating function Φ an (u, ϕ) we obtain the ALS probability distribution P(|ψ| 2 ) at |ψ| 2 ℓ 0 ≫ 1. As an auxiliary preliminary step, we found the asymptotic form of the generating function Φ an (u, ϕ) at u ≫ 1 which can be used to compute other statistical properties at the center-of-band anomaly. We show that at moderately large values of |ψ| 2 ℓ 0 , the probability of ALS at E = 0 is smaller than at energies away from the anomaly. However, at very large values of |ψ| 2 ℓ 0 , the tendency is inverted: it is exponentially easier to create a very strongly localized state at E = 0 than at energies away from the anomaly. We also found the leading term in the behavior of P(|ψ| 2 ) at small |ψ| 2 ≪ ℓ −1 0 and show that it is consistent with the exponential localization corresponding to the Lyapunov exponent found earlier by Kappus and Wegner. (paper)

  19. Optimizing mesoscopic two-band superconductors for observation of fractional vortex states

    Energy Technology Data Exchange (ETDEWEB)

    Piña, Juan C. [Departamento de Física, Universidade Federal de Pernambuco, Cidade Universitária, 50670-901 Recife, PE (Brazil); Núcleo de Tecnologia, CAA, Universidade Federal de Pernambuco, 55002-970 Caruaru, PE (Brazil); Souza Silva, Clécio C. de, E-mail: clecio@df.ufpe [Departamento de Física, Universidade Federal de Pernambuco, Cidade Universitária, 50670-901 Recife, PE (Brazil); Milošević, Milorad V. [Departamento de Física, Universidade Federal do Ceará, 60455-900 Fortaleza, Ceará (Brazil); Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium)

    2014-08-15

    Highlights: • Observation of fractional vortices in two-band superconductors of broad size range. • There is a minimal sample size for observing each particular fractional state. • Optimal value for stability of each fractional state is determined. • A suitable magnetic dot enhances stability even further. - Abstract: Using the two-component Ginzburg–Landau model, we investigate the effect of sample size and magnitude and homogeneity of external magnetic field on the stability of fractional vortex states in a mesoscopic two-band superconducting disk. We found that each fractional state has a preferable sample size, for which the range of applied field in which the state is stable is pronouncedly large. Vice versa, there exists an optimal magnitude of applied field for which a large range of possible sample radii will support the considered fractional state. Finally, we show that the stability of fractional states can be enhanced even further by magnetic nanostructuring of the sample, i.e. by suitably chosen geometrical parameters and magnetic moment of a ferromagnetic dot placed on top of the superconducting disk.

  20. Triaxial energy relation to describe rotational band in 98-112Ru nuclei

    International Nuclear Information System (INIS)

    Singh, Yuvraj; Gupta, K.K.; Bihari, Chhail; Varshney, A.K.; Varshney, Mani; Singh, M.; Gupta, D.K.

    2010-01-01

    In a broader perspective rotation vibration coupling parameter (b) is considered changing with the change in excitation energy (ε 1 ) and is evaluated on fitting experimental energy for 98-112 Ru isotopes in the frame work of general asymmetric rotor model. The moment of inertia parameter (a), common to yrast and quasi-γ band, is calculated from deformation parameter (β) using general empirical relation. The present work is undertaken to suggest some suitable equation for the trajectories which are similar in shape in 98-112 Ru nuclei

  1. Energy Efficiency Resources to Support State Energy Planning

    Energy Technology Data Exchange (ETDEWEB)

    Office of Strategic Programs, Strategic Priorities and Impact Analysis Team

    2017-06-01

    An early step for most energy efficiency planning is to identify and quantify energy savings opportunities, and then to understand how to access this potential. The U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy offers resources that can help with both of these steps. This fact sheet presents those resources. The resources are also available on the DOE State and Local Solution Center on the "Energy Efficiency: Savings Opportunities and Benefits" page: https://energy.gov/eere/slsc/energy-efficiency-savings-opportunities-and-benefits.

  2. States of high energy density

    International Nuclear Information System (INIS)

    Murray, M.

    1988-02-01

    The transverse energy, E/sub tau/ spectra for O 16 and S 32 incident for various elements at 200 GeVnucleon are shown. The target and projectile dependencies of the data are discussed. The energy density achieved is estimated. For O 16 on Tungsten the multiplicity spectrum is also presented as well as the pseudorapidity spectra as a function of the transverse energy. The multiplicity cross section dσdN as measured in the backward hemisphere (0.9 < /eta/ < 2.9/ is found to be very similar in shape to the transverse energy distribution dσdE/tau/ reflecting the particular geometry of nucleus nucleus nucleus collisions. The dependence on the atomic mass of the target, A/sub tau/ and projectile A/sub p/ is not what one would expect from naive considerations

  3. Electronic Energy Levels and Band Alignment for Aqueous Phenol and Phenolate from First Principles.

    Science.gov (United States)

    Opalka, Daniel; Pham, Tuan Anh; Sprik, Michiel; Galli, Giulia

    2015-07-30

    Electronic energy levels in phenol and phenolate solutions have been computed using density functional theory and many-body perturbation theory. The valence and conduction bands of the solvent and the ionization energies of the solutes have been aligned with respect to the vacuum level based on the concept of a computational standard hydrogen electrode. We have found significant quantitative differences between the generalized-gradient approximation, calculations with the HSE hybrid functional, and many-body perturbation theory in the G0W0 approximation. For phenol, two ionization energies below the photoionization threshold of bulk water have been assigned in the spectrum of Kohn-Sham eigenvalues of the solution. Deprotonation to phenolate was found to lift a third occupied energy level above the valence band maximum of the solvent which is characterized by an electronic lone pair at the hydroxyl group. The second and third ionization energies of phenolate were found to be very similar and explain the intensity pattern observed in recent experiments using liquid-microjet photoemission spectroscopy.

  4. Chiral classical states in a rhombus and a rhombi chain of Josephson junctions with two-band superconducting elements

    CERN Document Server

    Dias, R G; Coutinho, B C; Martins, L P

    2014-01-01

    We present a study of Josephson junctions arrays with two-band superconducting elements in the highcapacitance limit. We consider two particular geometries for these arrays: a single rhombus and a rhombi chain with two-band superconducting elements at the spinal positions. We show that the rhombus shaped JJ circuit and the rhombi chain can be mapped onto a triangular JJ circuit and a JJ two-leg ladder, respectively, with zero effective magnetic flux, but with Josephson couplings that are magnetic flux dependent. If the two-band superconductors are in a sign-reversed pairing state, one observes transitions to or from chiral phase configurations in the mapped superconducting arrays when magnetic flux or temperature are varied. The phase diagram for these chiral configurations is discussed. When half-flux quantum threads each rhombus plaquette, new phase configurations of the rhombi chain appear that are characterized by the doubling of the periodicity of the energy density along the chain, with every other two-...

  5. Ocean dynamic noise energy flux directivity in the 400 Hz to 700 Hz frequency band

    Institute of Scientific and Technical Information of China (English)

    Vladimir A. Shchurov; Galina F. Ivanova; Marianna V. Kuyanova; Helen S. Tkachenko

    2007-01-01

    Results of field studies of underwater dynamic noise energy flux directivity at two wind speeds, 6 m/s and 12 m/s, in the 400 Hz to 700 Hz frequency band in the deep open ocean are presented. The measurements were made by a freely drifting telemetric combined system at 500 m depth. Statistical characteristics of the horizontal and vertical dynamic noise energy flux directivity are considered as functions of wind speed and direction. Correlation between the horizontal dynamic noise energy flux direction and that of the wind was determined; a mechanism of the horizontal dynamic noise energy flux generation is related to the initial noise field scattering on ocean surface waves.

  6. Artificial neural network for suppression of banding artifacts in balanced steady-state free precession MRI.

    Science.gov (United States)

    Kim, Ki Hwan; Park, Sung-Hong

    2017-04-01

    The balanced steady-state free precession (bSSFP) MR sequence is frequently used in clinics, but is sensitive to off-resonance effects, which can cause banding artifacts. Often multiple bSSFP datasets are acquired at different phase cycling (PC) angles and then combined in a special way for banding artifact suppression. Many strategies of combining the datasets have been suggested for banding artifact suppression, but there are still limitations in their performance, especially when the number of phase-cycled bSSFP datasets is small. The purpose of this study is to develop a learning-based model to combine the multiple phase-cycled bSSFP datasets for better banding artifact suppression. Multilayer perceptron (MLP) is a feedforward artificial neural network consisting of three layers of input, hidden, and output layers. MLP models were trained by input bSSFP datasets acquired from human brain and knee at 3T, which were separately performed for two and four PC angles. Banding-free bSSFP images were generated by maximum-intensity projection (MIP) of 8 or 12 phase-cycled datasets and were used as targets for training the output layer. The trained MLP models were applied to another brain and knee datasets acquired with different scan parameters and also to multiple phase-cycled bSSFP functional MRI datasets acquired on rat brain at 9.4T, in comparison with the conventional MIP method. Simulations were also performed to validate the MLP approach. Both the simulations and human experiments demonstrated that MLP suppressed banding artifacts significantly, superior to MIP in both banding artifact suppression and SNR efficiency. MLP demonstrated superior performance over MIP for the 9.4T fMRI data as well, which was not used for training the models, while visually preserving the fMRI maps very well. Artificial neural network is a promising technique for combining multiple phase-cycled bSSFP datasets for banding artifact suppression. Copyright © 2016 Elsevier Inc. All

  7. State energy price and expenditure report, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-08-01

    The State Energy Price and Expenditure Report (SEPER) presents energy price and expenditure estimates individually for the 50 States and the District of Columbia and in aggregate for the US. The estimates developed in the State Energy Price and Expenditure Data System (SEPEDS) are provided by energy source and economic sector and are published for the years 1970 through 1995. Data for all years are available on a CD-ROM and via Internet. Consumption estimates used to calculate expenditures and the documentation for those estimates are taken from the State Energy Data Report 1995, Consumption Estimates (SEDR), published in December 1997. Expenditures are calculated by multiplying the price estimates by the consumption estimates, which are adjusted to remove process fuel; intermediate petroleum products; and other consumption that has no direct fuel costs, i.e., hydroelectric, geothermal, wind, solar, and photovoltaic energy sources.

  8. Optical band gap energy and ur bach tail of CdS:Pb2+ thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, M.; Juarez, H.; Pacio, M. [Universidad Autonoma de Puebla, Instituto de Ciencias, Centro de Investigacion en Dispositivos Semiconductores, Av. 14 Sur, Col. Jardines de San Manuel, Ciudad Universitaria, Puebla, Pue. (Mexico); Gutierrez, R.; Chaltel, L.; Zamora, M.; Portillo, O. [Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, Laboratorio de Materiales, Apdo. Postal 1067, 72001 Puebla, Pue. (Mexico); Mathew, X., E-mail: osporti@yahoo.mx [UNAM, Instituto de Energias Renovables, Temixco, Morelos (Mexico)

    2016-11-01

    Pb S-doped CdS nano materials were successfully synthesized using chemical bath. Transmittance measurements were used to estimate the optical band gap energy. Tailing in the band gap was observed and found to obey Ur bach rule. The diffraction X-ray show that the size of crystallites is in the ∼33 nm to 12 nm range. The peaks belonging to primary phase are identified at 2θ = 26.5 degrees Celsius and 2θ = 26.00 degrees Celsius corresponding to CdS and Pb S respectively. Thus, a shift in maximum intensity peak from 2θ = 26.4 to 28.2 degrees Celsius is clear indication of possible transformation of cubic to hexagonal phase. Also peaks at 2θ = 13.57, 15.9 degrees Celsius correspond to lead perchlorate thiourea. The effects on films thickness and substrate doping on the band gap energy and the width on tail were investigated. Increasing doping give rise to a shift in optical absorption edge ∼0.4 eV. (Author)

  9. Geothermal Energy Potential in Western United States

    Science.gov (United States)

    Pryde, Philip R.

    1977-01-01

    Reviews types of geothermal energy sources in the western states, including hot brine systems and dry steam systems. Conversion to electrical energy is a major potential use of geothermal energy, although it creates environmental disruptions such as noise, corrosion, and scaling of equipment. (AV)

  10. Identification of Soil Freezing and Thawing States Using SAR Polarimetry at C-Band

    Directory of Open Access Journals (Sweden)

    Thomas Jagdhuber

    2014-03-01

    Full Text Available The monitoring of soil freezing and thawing states over large areas is very challenging on ground. In order to investigate the potential and the limitations of space-borne SAR polarimetry at C-band for soil state survey, analyses were conducted on an entire winter time series of fully polarimetric RADARSAT-2 data from 2011/2012 to identify freezing as well as thawing states within the soil. The polarimetric data were acquired over the Sodankylä test site in Finland together with in situ measurements of the soil and the snow cover. The analyses indicate clearly that the dynamics of the polarimetric entropy and mean scattering alpha angle are directly correlated to soil freezing and thawing states, even under distinct dry snow cover. First modeling attempts using the Extended Bragg soil scattering model justify the observed trends, which indicate surface-like scattering during frozen soil conditions and multiple/volume scattering for thawed soils. Hence, these first investigations at C-band foster motivation to work towards a robust polarimetric detection of soil freezing and thawing states as well as their transition phase.

  11. Renewable energy atlas of the United States.

    Energy Technology Data Exchange (ETDEWEB)

    Kuiper, J.A.; Hlava, K.Greenwood, H.; Carr, A. (Environmental Science Division)

    2012-05-01

    The Renewable Energy Atlas (Atlas) of the United States is a compilation of geospatial data focused on renewable energy resources, federal land ownership, and base map reference information. It is designed for the U.S. Department of Agriculture Forest Service (USFS) and other federal land management agencies to evaluate existing and proposed renewable energy projects. Much of the content of the Atlas was compiled at Argonne National Laboratory (Argonne) to support recent and current energy-related Environmental Impact Statements and studies, including the following projects: (1) West-wide Energy Corridor Programmatic Environmental Impact Statement (PEIS) (BLM 2008); (2) Draft PEIS for Solar Energy Development in Six Southwestern States (DOE/BLM 2010); (3) Supplement to the Draft PEIS for Solar Energy Development in Six Southwestern States (DOE/BLM 2011); (4) Upper Great Plains Wind Energy PEIS (WAPA/USFWS 2012, in progress); and (5) Energy Transport Corridors: The Potential Role of Federal Lands in States Identified by the Energy Policy Act of 2005, Section 368(b) (in progress). This report explains how to add the Atlas to your computer and install the associated software; describes each of the components of the Atlas; lists the Geographic Information System (GIS) database content and sources; and provides a brief introduction to the major renewable energy technologies.

  12. Solid-state pulse modulator for a 1.7-MW X-band magnetron

    International Nuclear Information System (INIS)

    Choi, Jaegu; Shin, Yongmoon; Choi, Youngwook; Kim, Kwanho

    2014-01-01

    Medical linear accelerators (LINAC) for cancer treatment require pulse modulators to generate high-power pulses with a fast rise time, flat top and short duration to drive high-power magnetrons. Solid-state pulse modulators (SSPM) for medical LINACs that use high power semiconductor switches with high repetition rates, high stability and long lifetimes have been introduced to replace conventional linear-type pulse generators that use gaseous discharge switches. In this paper, the performance of a developed SSPM, which mainly consists of a capacitor charger, an insulated-gate bipolar transistor (IGBT) - capacitor stack and a pulse transformer, is evaluated with a dummy load and an X-band magnetron load. A theoretical analysis of the pulse transformer, which is a critical element of the SSPM, is carried out. The output pulse has a fast rise time and low droop, such that the modulator can drive the X-band magnetron.

  13. Energy Band Gap Dependence of Valley Polarization of the Hexagonal Lattice

    Science.gov (United States)

    Ghalamkari, Kazu; Tatsumi, Yuki; Saito, Riichiro

    2018-02-01

    The origin of valley polarization of the hexagonal lattice is analytically discussed by tight binding method as a function of energy band gap. When the energy gap decreases to zero, the intensity of optical absorption becomes sharp as a function of k near the K (or K') point in the hexagonal Brillouin zone, while the peak intensity at the K (or K') point keeps constant with decreasing the energy gap. When the dipole vector as a function of k can have both real and imaginary parts that are perpendicular to each other in the k space, the valley polarization occurs. When the dipole vector has only real values by selecting a proper phase of wave functions, the valley polarization does not occur. The degree of the valley polarization may show a discrete change that can be relaxed to a continuous change of the degree of valley polarization when we consider the life time of photo-excited carrier.

  14. Energy band structure tailoring of vertically aligned InAs/GaAsSb quantum dot structure for intermediate-band solar cell application by thermal annealing process.

    Science.gov (United States)

    Liu, Wei-Sheng; Chu, Ting-Fu; Huang, Tien-Hao

    2014-12-15

    This study presents an band-alignment tailoring of a vertically aligned InAs/GaAs(Sb) quantum dot (QD) structure and the extension of the carrier lifetime therein by rapid thermal annealing (RTA). Arrhenius analysis indicates a larger activation energy and thermal stability that results from the suppression of In-Ga intermixing and preservation of the QD heterostructure in an annealed vertically aligned InAs/GaAsSb QD structure. Power-dependent and time-resolved photoluminescence were utilized to demonstrate the extended carrier lifetime from 4.7 to 9.4 ns and elucidate the mechanisms of the antimony aggregation resulting in a band-alignment tailoring from straddling to staggered gap after the RTA process. The significant extension in the carrier lifetime of the columnar InAs/GaAsSb dot structure make the great potential in improving QD intermediate-band solar cell application.

  15. Influence of the aggregate state on band structure and optical properties of C60 computed with different methods

    Science.gov (United States)

    Pal, Amrita; Arabnejad, Saeid; Yamashita, Koichi; Manzhos, Sergei

    2018-05-01

    C60 and C60 based molecules are efficient acceptors and electron transport layers for planar perovskite solar cells. While properties of these molecules are well studied by ab initio methods, those of solid C60, specifically its optical absorption properties, are not. We present a combined density functional theory-Density Functional Tight Binding (DFTB) study of the effect of solid state packing on the band structure and optical absorption of C60. The valence and conduction band edge energies of solid C60 differ on the order of 0.1 eV from single molecule frontier orbital energies. We show that calculations of optical properties using linear response time dependent-DFT(B) or the imaginary part of the dielectric constant (dipole approximation) can result in unrealistically large redshifts in the presence of intermolecular interactions compared to available experimental data. We show that optical spectra computed from the frequency-dependent real polarizability can better reproduce the effect of C60 aggregation on optical absorption, specifically with a generalized gradient approximation functional, and may be more suited to study effects of molecular aggregation.

  16. A simplified approach to the band gap correction of defect formation energies: Al, Ga, and In-doped ZnO

    Science.gov (United States)

    Saniz, R.; Xu, Y.; Matsubara, M.; Amini, M. N.; Dixit, H.; Lamoen, D.; Partoens, B.

    2013-01-01

    The calculation of defect levels in semiconductors within a density functional theory approach suffers greatly from the band gap problem. We propose a band gap correction scheme that is based on the separation of energy differences in electron addition and relaxation energies. We show that it can predict defect levels with a reasonable accuracy, particularly in the case of defects with conduction band character, and yet is simple and computationally economical. We apply this method to ZnO doped with group III elements (Al, Ga, In). As expected from experiment, the results indicate that Zn substitutional doping is preferred over interstitial doping in Al, Ga, and In-doped ZnO, under both zinc-rich and oxygen-rich conditions. Further, all three dopants act as shallow donors, with the +1 charge state having the most advantageous formation energy. Also, doping effects on the electronic structure of ZnO are sufficiently mild so as to affect little the fundamental band gap and lowest conduction bands dispersion, which secures their n-type transparent conducting behavior. A comparison with the extrapolation method based on LDA+U calculations and with the Heyd-Scuseria-Ernzerhof hybrid functional (HSE) shows the reliability of the proposed scheme in predicting the thermodynamic transition levels in shallow donor systems.

  17. "Assistance to States on Geothermal Energy"

    Energy Technology Data Exchange (ETDEWEB)

    Linda Sikkema; Jennifer DeCesaro

    2006-07-10

    This final report summarizes work carried out under agreement with the U.S. Department of Energy, related to geothermal energy policy issues. This project has involved a combination of outreach and publications on geothermal energy—Contract Number DE-FG03-01SF22367—with a specific focus on educating state-level policymakers. Education of state policymakers is vitally important because state policy (in the form of incentives or regulation) is a crucial part of the success of geothermal energy. State policymakers wield a significant influence over all of these policies. They are also in need of high quality, non-biased educational resources which this project provided. This project provided outreach to legislatures, in the form of responses to information requests on geothermal energy and publications. The publications addressed: geothermal leasing, geothermal policy, constitutional and statutory authority for the development of geothermal district energy systems, and state regulation of geothermal district energy systems. These publications were distributed to legislative energy committee members, and chairs, legislative staff, legislative libraries, and other related state officials. The effect of this effort has been to provide an extensive resource of information about geothermal energy for state policymakers in a form that is useful to them. This non-partisan information has been used as state policymakers attempt to develop their own policy proposals related to geothermal energy in the states. Coordination with the National Geothermal Collaborative: NCSL worked and coordinated with the National Geothermal Collaborative (NGC) to ensure that state legislatures were represented in all aspects of the NGC's efforts. NCSL participated in NGC steering committee conference calls, attended and participated in NGC business meetings and reviewed publications for the NGC. Additionally, NCSL and WSUEP staff drafted a series of eight issue briefs published by the

  18. State energy-price system: 1981 update

    Energy Technology Data Exchange (ETDEWEB)

    Fang, J.M.; Imhoff, K.L.; Hood, L.J.

    1983-08-01

    This report updates the State Energy Price Data System (STEPS) to include state-level energy prices by fuel and by end-use sectors for 1981. Both physical unit prices and Btu prices are presented. Basic documentation of the data base remains generally the same as in the original report: State Energy Price System; Volume 1: Overview and Technical Documentation (DOE/NBB-0029 Volume 1 of 2, November 1982). The present report documents only the changes in procedures necessitated by the update to 1981 and the corrections to the basic documentation.

  19. Solar energy in the United States

    International Nuclear Information System (INIS)

    Ochoa, D.; Slaoui, A.; Soler, R.; Bermudez, V.

    2009-01-01

    Written by a group of five French experts who visited several research centres, innovating companies and solar power stations in the United States, this report first proposes an overview of solar energy in the United States, indicating and commenting the respective shares of different renewable energies in the production, focusing on the photovoltaic energy production and its RD sector. The second part presents industrial and research activities in the solar sector, and more specifically photovoltaic technologies (silicon and thin layer technology) and solar concentrators (thermal solar concentrators, photovoltaic concentrators). The last chapter presents the academic research activities in different universities (California Tech Beckman Institute, Stanford, National Renewable Energy Laboratory, Colorado School of Mines)

  20. Estimated United States Transportation Energy Use 2005

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C A; Simon, A J; Belles, R D

    2011-11-09

    A flow chart depicting energy flow in the transportation sector of the United States economy in 2005 has been constructed from publicly available data and estimates of national energy use patterns. Approximately 31,000 trillion British Thermal Units (trBTUs) of energy were used throughout the United States in transportation activities. Vehicles used in these activities include automobiles, motorcycles, trucks, buses, airplanes, rail, and ships. The transportation sector is powered primarily by petroleum-derived fuels (gasoline, diesel and jet fuel). Biomass-derived fuels, electricity and natural gas-derived fuels are also used. The flow patterns represent a comprehensive systems view of energy used within the transportation sector.

  1. Excitation energy transfer from the bacteriochlorophyll Soret band to carotenoids in the LH2 light-harvesting complex from Ectothiorhodospira haloalkaliphila is negligible.

    Science.gov (United States)

    Razjivin, A P; Lukashev, E P; Kompanets, V O; Kozlovsky, V S; Ashikhmin, A A; Chekalin, S V; Moskalenko, A A; Paschenko, V Z

    2017-09-01

    Pathways of intramolecular conversion and intermolecular electronic excitation energy transfer (EET) in the photosynthetic apparatus of purple bacteria remain subject to debate. Here we experimentally tested the possibility of EET from the bacteriochlorophyll (BChl) Soret band to the singlet S 2 level of carotenoids using femtosecond pump-probe measurements and steady-state fluorescence excitation and absorption measurements in the near-ultraviolet and visible spectral ranges. The efficiency of EET from the Soret band of BChl to S 2 of the carotenoids in light-harvesting complex LH2 from the purple bacterium Ectothiorhodospira haloalkaliphila appeared not to exceed a few percent.

  2. A New Fractal-Based Miniaturized Dual Band Patch Antenna for RF Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Sika Shrestha

    2014-01-01

    Full Text Available The growth of wireless communications in recent years has made it necessary to develop compact, lightweight multiband antennas. Compact antennas can achieve the same performance as large antennas do with low price and with greater system integration. Dual-frequency microstrip antennas for transmission and reception represent promising approach for doubling the system capacity. In this work, a miniaturized dual band antenna operable at 2.45 and 5.8 GHz is constructed by modifying the standard microstrip patch antenna geometry into a fractal structure. In addition to miniaturization and dual band nature, the proposed antenna also removes unwanted harmonics without the use of additional filter component. Using a finite-element-method-based high frequency structure simulator (HFSS, the antenna is designed and its performance in terms of return loss, impedance matching, radiation pattern, and voltage standing wave ratio (VSWR is demonstrated. Simulation results are shown to be in close agreement with performance measurements from an actual antenna fabricated on an FR4 substrate. The proposed antenna can be integrated with a rectifier circuit to develop a compact rectenna that can harvest RF energy in both of these frequency bands at a reduction in size of 25.98% relative to a conventional rectangular patch antenna.

  3. A novel approach for characterizing broad-band radio spectral energy distributions

    Science.gov (United States)

    Harvey, V. M.; Franzen, T.; Morgan, J.; Seymour, N.

    2018-05-01

    We present a new broad-band radio frequency catalogue across 0.12 GHz ≤ ν ≤ 20 GHz created by combining data from the Murchison Widefield Array Commissioning Survey, the Australia Telescope 20 GHz survey, and the literature. Our catalogue consists of 1285 sources limited by S20 GHz > 40 mJy at 5σ, and contains flux density measurements (or estimates) and uncertainties at 0.074, 0.080, 0.119, 0.150, 0.180, 0.408, 0.843, 1.4, 4.8, 8.6, and 20 GHz. We fit a second-order polynomial in log-log space to the spectral energy distributions of all these sources in order to characterize their broad-band emission. For the 994 sources that are well described by a linear or quadratic model we present a new diagnostic plot arranging sources by the linear and curvature terms. We demonstrate the advantages of such a plot over the traditional radio colour-colour diagram. We also present astrophysical descriptions of the sources found in each segment of this new parameter space and discuss the utility of these plots in the upcoming era of large area, deep, broad-band radio surveys.

  4. Efficient in-band diode-pumped Q-switched solid state laser for methane detection, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop an efficient, tunable Q-switched SSL operating at a wavelength of 1651 nm with pulse energy >1 mJ at 2000 Hz repetition rate with in-band...

  5. Local density of optical states in the band gap of a finite one-dimensional photonic crystal

    NARCIS (Netherlands)

    Yeganegi Dastgerdi, Elahe; Lagendijk, Aart; Mosk, Allard; Vos, Willem L.

    2014-01-01

    We study the local density of states (LDOS) in a finite photonic crystal, in particular in the frequency range of the band gap. We propose an original point of view on the band gap, which we consider to be the result of vacuum fluctuations in free space that tunnel in the forbidden range in the

  6. Term value/band-gap energy correlations for solid rare gas excitons

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Term value/ionization energy correlation algorithms have proven to be of considerable utility in the assignment of atomic and molecular Rydberg states. Many examples of empirical term value/ionization energy correlations are known for diverse classes of atoms and molecules. The purpose of this paper is to demonstrate that similar correlations are also obtained for excitons in rare gas solids

  7. State estimation for wave energy converters

    Energy Technology Data Exchange (ETDEWEB)

    Bacelli, Giorgio; Coe, Ryan Geoffrey

    2017-04-01

    This report gives a brief discussion and examples on the topic of state estimation for wave energy converters (WECs). These methods are intended for use to enable real-time closed loop control of WECs.

  8. Non-Dirac Chern insulators with large band gaps and spin-polarized edge states.

    Science.gov (United States)

    Xue, Y; Zhang, J Y; Zhao, B; Wei, X Y; Yang, Z Q

    2018-05-10

    Based on first-principles calculations and k·p models, we demonstrate that PbC/MnSe heterostructures are a non-Dirac type of Chern insulator with very large band gaps (244 meV) and exotically half-metallic edge states, providing the possibilities of realizing very robust, completely spin polarized, and dissipationless spintronic devices from the heterostructures. The achieved extraordinarily large nontrivial band gap can be ascribed to the contribution of the non-Dirac type electrons (composed of px and py) and the very strong atomic spin-orbit coupling (SOC) interaction of the heavy Pb element in the system. Surprisingly, the band structures are found to be sensitive to the different exchange and correlation functionals adopted in the first-principles calculations. Chern insulators with various mechanisms are acquired from them. These discoveries show that the predicted nontrivial topology in PbC/MnSe heterostructures is robust and can be observed in experiments at high temperatures. The system has great potential to have attractive applications in future spintronics.

  9. Energy efficient solid state lighting

    Energy Technology Data Exchange (ETDEWEB)

    Dam-Hansen, C.; Petersen, Poul Michael

    2012-11-15

    Even though vast improvements have been made on efficiency and light quality, SSL is still in its infancy. One of the barriers for a market introduction is the price, which still is around 5 times higher than traditional lighting technologies. In order to fulfil the potential of SSL, further research and development needs to increase the light extraction from semiconductor materials, provide better and cheaper production and packaging, and advanced optical systems for optimized light distribution and new thermal solutions for SSL lamps and luminaires. Nanotechnology and applied research at DTU Fotonik in close collaboration with industry are essential parts in the development of new enhanced LED optical systems and LEDs with higher light extraction efficiency. Photonic crystals can help to efficiently extract light from LEDs and to form a desired emission profile. Future directions are devoted to the next generation of LEDs, in which the spontaneous emission is photon enhanced. One realization of this idea is using LEDs with a layer of nanocrystals, which are coupled to the quantum well of the LED. Such R and D work is ongoing all over the world and DOE roadmaps foresee luminous efficiencies by 2020 that are close to 250 lm/W for both cold and warm white light from LEDs, and prices in the order of one dollar per kilolumen. Such figures will drastically reduce the energy consumption worldwide for lighting, and hence a marked reduction in carbon emissions. (Author)

  10. State energy conservation plan for New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-01-01

    The energy-savings and energy-management programs set up by state agencies in New Mexico are presented. Also the energy-savings and energy-management programs for public schools are presented. Plans and summaries are also given for the following program: solar water heaters for secondary schools; solar portable classroom demonstration; energy-savings and energy-management programs for county and municipal governments; energy-savings programs for commercial and residential sectors; weatherization; solar sustenance; energy-savings programs for hospitals and industrial buildings; carpools and vanpools; a program encouraging compliance with the national 55-mph speed limit; waste-oil recycling; utilitites; agriculture; procurement; modification; public information; and an administrative packet containing information on how to facilitate internal accounting procedures.

  11. The United States and world energy markets

    International Nuclear Information System (INIS)

    Ramsay, W.C.

    1992-01-01

    The United States, dominating the world's energy markets as a producer and consumer, is sensitive to changes in this market and intends to influence the development of global energy policy. Supply will be increased by nations such as Venezuela, Indonesia and perhaps in the future a United Yemen and the Commonwealth of Independent States, moving to freer market economies which will allow investment opportunities previously inaccessible to foreign companies. Although world energy demand will grow, little of this will be in the US where, under the National Energy Strategy, comprehensive measures are being introduced to improve energy efficiency. The US energy security will be further improved by such measures as diversification of supply, larger domestic production and increasing interdependence between suppliers, traders and consumers. (author)

  12. State energy price and expenditure report 1989

    International Nuclear Information System (INIS)

    1991-01-01

    The State Energy Price and Expenditure Report (SEPER) presents energy price and expenditure estimates for the 50 States, the District of Columbia, and the United States. The estimates are provided by energy source (e.g., petroleum, natural gas, coal, and electricity) and by major consuming or economic sector. This report is an update of the State Energy Price and Expenditure Report 1988 published in September 1990. Changes from the last report are summarized in a section of the documentation. Energy price and expenditure estimates are published for the years 1970, 1975, 1980, and 1985 through 1989. Documentation follows the tables and describes how the price estimates are developed, including sources of data, methods of estimation, and conversion factors applied. Consumption estimates used to calculate expenditures, and the documentation for those estimates, are from the State Energy Data Report, Consumption Estimates, 1960--1989 (SEDR), published in May 1991. Expenditures are calculated by multiplying the price estimates by the consumption estimates, adjusted to remove process fuel and intermediate product consumption. All expenditures are consumer expenditures, that is, they represent estimates of money directly spent by consumers to purchase energy, generally including taxes. 11 figs., 43 tabs

  13. State energy price and expenditure report 1989

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-30

    The State Energy Price and Expenditure Report (SEPER) presents energy price and expenditure estimates for the 50 States, the District of Columbia, and the United States. The estimates are provided by energy source (e.g., petroleum, natural gas, coal, and electricity) and by major consuming or economic sector. This report is an update of the State Energy Price and Expenditure Report 1988 published in September 1990. Changes from the last report are summarized in a section of the documentation. Energy price and expenditure estimates are published for the years 1970, 1975, 1980, and 1985 through 1989. Documentation follows the tables and describes how the price estimates are developed, including sources of data, methods of estimation, and conversion factors applied. Consumption estimates used to calculate expenditures, and the documentation for those estimates, are from the State Energy Data Report, Consumption Estimates, 1960--1989 (SEDR), published in May 1991. Expenditures are calculated by multiplying the price estimates by the consumption estimates, adjusted to remove process fuel and intermediate product consumption. All expenditures are consumer expenditures, that is, they represent estimates of money directly spent by consumers to purchase energy, generally including taxes. 11 figs., 43 tabs.

  14. Energy policy in the United States

    Energy Technology Data Exchange (ETDEWEB)

    McCormack, M

    1978-06-01

    Energy policy in the United States is examined with particular regard to the nuclear power industry. The advantages of nuclear power over conventional and other sources are presented and the vigorous expansion of research and development is advocated. Future energy supplies are discussed and the author stresses the necessity for continued research into breeder technology.

  15. Optical density of states in ultradilute GaAsN alloy: Coexistence of free excitons and impurity band of localized and delocalized states

    Energy Technology Data Exchange (ETDEWEB)

    Bhuyan, Sumi; Pal, Bipul; Bansal, Bhavtosh, E-mail: bhavtosh@iiserkol.ac.in [Indian Institute of Science Education and Research Kolkata, Mohanpur Campus, Nadia 741252, West Bengal (India); Das, Sanat K.; Dhar, Sunanda [Department of Electronic Science, University of Calcutta, 92 A.P.C. Road, Kolkata 700009 (India)

    2014-07-14

    Optically active states in liquid phase epitaxy-grown ultra-dilute GaAsN are studied. The feature-rich low temperature photoluminescence spectrum has contributions from excitonic band states of the GaAsN alloy, and two types of defect states—localized and extended. The degree of delocalization for extended states both within the conduction and defect bands, characterized by the electron temperature, is found to be similar. The degree of localization in the defect band is analyzed by the strength of the phonon replicas. Stronger emission from these localized states is attributed to their giant oscillator strength.

  16. State energy severance taxes, 1985-1993

    International Nuclear Information System (INIS)

    1995-09-01

    This report analyzes changes in aggregate and State-level energy severance taxes for 1985 through 1993. Data are presented for crude oil, natural gas, and coal. The report highlights trends in severance tax receipts relative to energy prices and production, using severance tax data published by the Bureau of the Census of the US Department of Commerce and production data published by the Energy Information Administration

  17. Energy-expending behaviour in frightened caribou when dispersed singly or in small bands

    Directory of Open Access Journals (Sweden)

    Otto Blehr

    1997-04-01

    Full Text Available The behaviour of single, and small bands of caribou (Rangifer tarandus groenlandicus when confronted by humans was compared with the energy—saving behaviour zoologists have ascribed to caribou in encounters with non-hunting wolves (Canis lupus. When confronted by me, or upon getting my scent, caribou ran away on all occasions. Their flight was occasionally interrupted by short stops to look back in my direction, but would continue on all occasions until they were out of sight. This behaviour is inconsistent with the one ascribed to caribou by zoologists when the intruder is a wolf instead of a human. In their view, the caribou stop their flight soon after the wolf gives up the chase, and accordingly save energy owing to their ability to distinguish between hunting and non-hunting wolves. However, small bands of caribou, as well as single animals, have never been observed to behave in this manner. On the contrary, the behaviour of caribou in such encounters is known to follow the same pattern as in their encounters with humans. Energy—saving behaviour is, however, sometimes observed when caribou become inquisitive about something in their surroundings. They will then readily approach as well as try to get down-wind of the object. When the object does not induce fear, it may simply be ignored, or charged before the caribou calm down. The effect of this "confirming behaviour" is that energy which would otherwise have been spent in needless flights from non-predators is saved.

  18. Composite Piezoelectric Rubber Band for Energy Harvesting from Breathing and Limb Motion

    International Nuclear Information System (INIS)

    Wang, Jhih-Jhe; Su, Huan-Jan; Hsu, Chang-I; Su, Yu-Chuan

    2014-01-01

    We have successfully demonstrated the design and microfabrication of piezoelectric rubber bands and their application in energy harvesting from human motions. Composite polymeric and metallic microstructures with embedded bipolar charges are employed to realize the desired stretchability and electromechanical sensitivity. In the prototype demonstration, multilayer PDMS cellular structures coated with PTFE films and stretchable gold electrodes are fabricated and implanted with bipolar charges. The composite structures show elasticity of 300∼600 kPa and extreme piezoelectricity of d 33 >2000 pC/N and d 31 >200 pC/N. For a working volume of 2.5cm×2.5cm×0.3mm, 10% (or 2.5mm) stretch results in effective d 31 of >17000 pC/N. It is estimated that electric charge of >0.2 μC can be collected and stored per breath (or 2.5cm deformation). As such, the composite piezoelectric rubber bands (with spring constants of ∼200 N/m) can be mounted on elastic waistbands to harvest the circumferential stretch during breathing, or on pads around joints to harvest the elongation during limb motion. Furthermore, the wearable piezoelectric structures can be spread, stacked and connected to charge energy storages and power micro devices

  19. Composite Piezoelectric Rubber Band for Energy Harvesting from Breathing and Limb Motion

    Science.gov (United States)

    Wang, Jhih-Jhe; Su, Huan-Jan; Hsu, Chang-I.; Su, Yu-Chuan

    2014-11-01

    We have successfully demonstrated the design and microfabrication of piezoelectric rubber bands and their application in energy harvesting from human motions. Composite polymeric and metallic microstructures with embedded bipolar charges are employed to realize the desired stretchability and electromechanical sensitivity. In the prototype demonstration, multilayer PDMS cellular structures coated with PTFE films and stretchable gold electrodes are fabricated and implanted with bipolar charges. The composite structures show elasticity of 300~600 kPa and extreme piezoelectricity of d33 >2000 pC/N and d31 >200 pC/N. For a working volume of 2.5cm×2.5cm×0.3mm, 10% (or 2.5mm) stretch results in effective d31 of >17000 pC/N. It is estimated that electric charge of >0.2 μC can be collected and stored per breath (or 2.5cm deformation). As such, the composite piezoelectric rubber bands (with spring constants of ~200 N/m) can be mounted on elastic waistbands to harvest the circumferential stretch during breathing, or on pads around joints to harvest the elongation during limb motion. Furthermore, the wearable piezoelectric structures can be spread, stacked and connected to charge energy storages and power micro devices.

  20. State-to-state dynamics of molecular energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Gentry, W.R.; Giese, C.F. [Univ. of Minnesota, Minneapolis (United States)

    1993-12-01

    The goal of this research program is to elucidate the elementary dynamical mechanisms of vibrational and rotational energy transfer between molecules, at a quantum-state resolved level of detail. Molecular beam techniques are used to isolate individual molecular collisions, and to control the kinetic energy of collision. Lasers are used both to prepare specific quantum states prior to collision by stimulated-emission pumping (SEP), and to measure the distribution of quantum states in the collision products by laser-induced fluorescence (LIF). The results are interpreted in terms of dynamical models, which may be cast in a classical, semiclassical or quantum mechanical framework, as appropriate.

  1. A simple model for conduction band states of nitride-based double heteroestructures

    Energy Technology Data Exchange (ETDEWEB)

    Gaggero-Sager, L M; Mora-Ramos, M E, E-mail: lgaggero@uaem.m [Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico)

    2009-05-01

    In this work we propose an analytical expression for the approximate modeling of the potential energy function describing conduction band bending in III-V nitride quantum wells. It is an alternative approach to the self-consistent Poisson-Schoedinger calculation. The model considers the influence of the many electron system and the built-in electric field inside the well. Hartree and exchange contributions are included along the lines of a local-density Thomas-Fermi-based theory. The effects due to the modulated doping in the barriers is also considered. We report the calculation of the energy spectrum as a function of several input parameters: alloy composition in the barriers, barrier doping concentration, and quantum well width. Our results could be of usefulness in the study of optoelectronic properties in this kind of systems.

  2. High-Efficiency, Ka-band Solid-State Power Amplifier Utilizing GaN Technology, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — QuinStar Technology proposes to develop an efficient, solid-state power amplifier (SSPA), operating at Ka-band frequencies, for high data rate, long range space...

  3. High-Efficiency, Ka-Band Solid-State Power Amplifier Utilizing GaN Technology, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — QuinStar Technology proposes to develop a high-efficiency, solid-state power amplifier (SSPA), operating at Ka-band frequencies, for high data rate, long range space...

  4. Martensitic transformation between competing phases in Ti–Ta alloys: a solid-state nudged elastic band study

    International Nuclear Information System (INIS)

    Chakraborty, Tanmoy; Rogal, Jutta; Drautz, Ralf

    2015-01-01

    A combined density functional theory and solid-state nudged elastic band study is presented to investigate the martensitic transformation between β → (α″, ω) phases in the Ti–Ta system. The minimum energy paths along the transformation are calculated and the transformation mechanisms as well as relative stabilities of the different phases are discussed for various compositions. The analysis of the transformation paths is complemented by calculations of phonon spectra to determine the dynamical stability of the β, α″, and ω phase. Our theoretical results confirm the experimental findings that with increasing Ta concentration there is a competition between the destabilisation of the α″ and ω phase and the stabilisation of the high-temperature β phase. (paper)

  5. Unleashing elastic energy: dynamics of energy release in rubber bands and impulsive biological systems

    Science.gov (United States)

    Ilton, Mark; Cox, Suzanne; Egelmeers, Thijs; Patek, S. N.; Crosby, Alfred J.

    Impulsive biological systems - which include mantis shrimp, trap-jaw ants, and venus fly traps - can reach high speeds by using elastic elements to store and rapidly release energy. The material behavior and shape changes critical to achieving rapid energy release in these systems are largely unknown due to limitations of materials testing instruments operating at high speed and large displacement. In this work, we perform fundamental, proof-of-concept measurements on the tensile retraction of elastomers. Using high speed imaging, the kinematics of retraction are measured for elastomers with varying mechanical properties and geometry. Based on the kinematics, the rate of energy dissipation in the material is determined as a function of strain and strain-rate, along with a scaling relation which describes the dependence of maximum velocity on material properties. Understanding this scaling relation along with the material failure limits of the elastomer allows the prediction of material properties required for optimal performance. We demonstrate this concept experimentally by optimizing for maximum velocity in our synthetic model system, and achieve retraction velocities that exceed those in biological impulsive systems. This model system provides a foundation for future work connecting continuum performance to molecular architecture in impulsive systems.

  6. Wobbling Motion in the Multi-Bands Crossing Region: Dynamical Coupling Mode Between High- and Low-K States

    International Nuclear Information System (INIS)

    Oi, M.; Ansari, A.; Horibata, T.; Onishi, N.; Walker, P.M.

    2001-01-01

    We analyze a mechanism of coupling of high- and low-K bands in terms of a dynamical treatment for nuclear rotations, i. e., wobbling motion. The wobbling states are produced through the Generator Coordinate Method after Angular Momentum Projection (GCM-after-AMP), in which the intrinsic states are constructed through fully self consistent calculations by the 2d-cranked (or tilted-axis-cranked) HFB method. In particular, the phenomena of ''signature inversion'' and ''signature splitting'' in the t-band (tilted rotational band) are explained in terms of the wobbling model. Our calculations will be compared with new data for in-band E2 transition rates in 182 0s, which may shed light on the mechanism of the anomalous K = 25 isomer decay, directly to the yrast band. (author)

  7. Transition state region in the A-Band photodissociation of allyl iodide—A femtosecond extreme ultraviolet transient absorption study

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacherjee, Aditi, E-mail: abhattacherjee@berkeley.edu, E-mail: andrewattar@berkeley.edu; Attar, Andrew R., E-mail: abhattacherjee@berkeley.edu, E-mail: andrewattar@berkeley.edu [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Leone, Stephen R., E-mail: srl@berkeley.edu [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Physics, University of California, Berkeley, California 94720 (United States)

    2016-03-28

    Femtosecond extreme ultraviolet (XUV) transient absorption spectroscopy based on a high-harmonic generation source is used to study the 266 nm induced A-band photodissociation dynamics of allyl iodide (CH{sub 2} =CHCH{sub 2}I). The photolysis of the C—I bond at this wavelength produces iodine atoms both in the ground ({sup 2}P{sub 3/2}, I) and spin-orbit excited ({sup 2}P{sub 1/2}, I*) states, with the latter as the predominant channel. Using XUV absorption at the iodine N{sub 4/5} edge (45–60 eV), the experiments constitute a direct probe of not only the long-lived atomic iodine reaction products but also the fleeting transition state region of the repulsive n{sub I}σ{sup ∗}{sub C—I} excited states. Specifically, three distinct features are identified in the XUV transient absorption spectrum at 45.3 eV, 47.4 eV, and 48.4 eV (denoted transients A, B, and C, respectively), which arise from the repulsive valence-excited nσ{sup ∗} states and project onto the high-lying core-excited states of the dissociating molecule via excitation of 4d(I) core electrons. Transients A and B originate from 4d(I) → n(I) core-to-valence transitions, whereas transient C is best assigned to a 4d(I) →σ{sup ∗}(C—I) transition. The measured differential absorbance of these new features along with the I/I* branching ratios known from the literature is used to suggest a more definitive assignment, albeit provisional, of the transients to specific dissociative states within the A-band manifold. The transients are found to peak around 55 fs–65 fs and decay completely by 145 fs–185 fs, demonstrating the ability of XUV spectroscopy to map the evolution of reactants into products in real time. The similarity in the energies of transients A and B with analogous features observed in methyl iodide [Attar et al. J. Phys. Chem. Lett. 6, 5072, (2015)] together with the new observation of transient C in the present work provides a more complete picture of the valence electronic

  8. Balanced homodyne detection of optical quantum states at audio-band frequencies and below

    International Nuclear Information System (INIS)

    Stefszky, M S; Mow-Lowry, C M; Chua, S S Y; Shaddock, D A; Buchler, B C; Lam, P K; McClelland, D E; Vahlbruch, H; Khalaidovski, A; Schnabel, R

    2012-01-01

    The advent of stable, highly squeezed states of light has generated great interest in the gravitational wave community as a means for improving the quantum-noise-limited performance of advanced interferometric detectors. To confidently measure these squeezed states, it is first necessary to measure the shot-noise across the frequency band of interest. Technical noise, such as non-stationary events, beam pointing, and parasitic interference, can corrupt shot-noise measurements at low Fourier frequencies, below tens of kilo-hertz. In this paper we present a qualitative investigation into all of the relevant noise sources and the methods by which they can be identified and mitigated in order to achieve quantum noise limited balanced homodyne detection. Using these techniques, flat shot-noise down to Fourier frequencies below 0.5 Hz is produced. This enables the direct observation of large magnitudes of squeezing across the entire audio-band, of particular interest for ground-based interferometric gravitational wave detectors. 11.6 dB of shot-noise suppression is directly observed, with more than 10 dB down to 10 Hz. (paper)

  9. Emergent low-energy bound states in the two-orbital Hubbard model

    Science.gov (United States)

    Núñez-Fernández, Y.; Kotliar, G.; Hallberg, K.

    2018-03-01

    A repulsive Coulomb interaction between electrons in different orbitals in correlated materials can give rise to bound quasiparticle states. We study the nonhybridized two-orbital Hubbard model with intra- (inter)orbital interaction U (U12) and different bandwidths using an improved dynamical mean-field theory numerical technique which leads to reliable spectra on the real energy axis directly at zero temperature. We find that a finite density of states at the Fermi energy in one band is correlated with the emergence of well-defined quasiparticle states at excited energies Δ =U -U12 in the other band. These excitations are interband holon-doublon bound states. At the symmetric point U =U12 , the quasiparticle peaks are located at the Fermi energy, leading to a simultaneous and continuous Mott transition settling a long-standing controversy.

  10. Energy in a state of shock

    International Nuclear Information System (INIS)

    Chevalier, Jean-Marie; Pastre, Olivier; Mestrallet, Gerard; Jouzel, Jean; Geoffron, Patrice; Boniface, Pascal; Lorenzi, Jean-Herve; Bornard, Pierre; Levitte, Jean-David; Jacquillat, Bertrand; Gallois, Louis; Gaymard, Clara; Perthuis, Christian de; Schwarz, Virginie; Lechevin, Bruno; Baud, Olivier; Moulin, Julien

    2015-01-01

    The news concerning energy are in a continuous state of shock: falling oil prices, shale gas revolution in the US, energy transition policies, gas crisis between Russia and Ukraine, etc. The energy world is also facing major challenges, notably the climatic change. In its first part, this book presents in a highly pedagogical way, the key world energy data and their main economic, environmental and political related issues. Issues and perspectives are described for each energy system, with a particular interest in the European energy system and the future 'Energy Union' that is intended to secure the european energy supply. In the second part, the authors give the floor to twelve experts who raise alarm about the specific energy issue before the forthcoming COP 21 conference on climatic change in Paris: overview of the climatic change issue (by Jean Jouzel), energy transition policies in Europe (by Patrice Geoffron), the negotiations inside a hypothetical 'international community' (by Pascal Boniface), energy transition and financing, the green growth, giving a price to carbon, energy policy and democracy, etc

  11. Fine structure and energy spectrum of exciton in direct band gap cubic semiconductors with degenerate valence bands

    International Nuclear Information System (INIS)

    Nguyen Toan Thang; Nguyen Ai Viet; Nguyen Que Huong

    1987-06-01

    The influence of the cubic structure on the energy spectrum of direct exciton is investigated, using the new method suggested by Nguyen Van Hieu and co-workers. Explicit expressions of the exciton energy levels 1S, 2S and 2P are derived. A comparison with the experiments and the other theory is done for ZnSe. (author). 10 refs, 1 fig., 2 tabs

  12. Matrix elements of intraband transitions in quantum dot intermediate band solar cells: the influence of quantum dot presence on the extended-state electron wave-functions

    International Nuclear Information System (INIS)

    Nozawa, Tomohiro; Arakawa, Yasuhiko

    2014-01-01

    The intraband transitions which are essential for quantum dot intermediate band solar cells (QD IBSCs) are theoretically investigated by estimating the matrix elements from a ground bound state, which is often regarded as an intermediate band (IB), to conduction band (CB) states for a structure with a quantum dot (QD) embedded in a matrix (a QD/matrix structure). We have found that the QD pushes away the electron envelope functions (probability densities) from the QD region in almost all quantum states above the matrix CB minimum. As a result, the matrix elements of the intraband transitions in the QD/matrix structure are largely reduced, compared to those calculated assuming the envelope functions of free electrons (i.e., plane-wave envelope functions) in a matrix structure as the final states of the intraband transitions. The result indicates the strong influence of the QD itself on the intraband transitions from the IB to the CB states in QD IBSC devices. This work will help in better understanding the problem of the intraband transitions and give new insight, that is, engineering of quantum states is indispensable for the realization of QD IBSCs with high solar energy conversion efficiencies. (paper)

  13. Steady-state emission of blazars at very high energies

    International Nuclear Information System (INIS)

    Hoehne-Moench, Daniel

    2010-01-01

    One key scientific program of the MAGIC telescope project is the discovery and detection of blazars. They constitute the most prominent extragalactic source class in the very high energy (VHE) γ-ray regime with 29 out of 34 known objects. Therefore a major part of the available observation time was spent in the last years on high-frequency peaked blazars. The selection criteria were chosen to increase the detection probability. As the X-ray flux is believed to be correlated to the VHE γ-ray flux, only X-ray selected sources with a flux F X >2 μJy at 1 keV were considered. To avoid strong attenuation of the -rays in the extragalactic infrared background, the redshift was restricted to values between z X-γ between the X-ray range at 1 keV and the VHE γ-ray regime at 200 GeV were calculated. The majority of objects show a spectral behaviour as expected from the source class of HBLs: The energy output in the VHE regime is in general lower than in X-rays. For the stacked blazar sample the broad-band spectral index was calculated to α X-γ =1.09, confirming the result found for the individual objects. Another evidence for the revelation of the baseline emission is the broad-band spectral energy distribution (SED) comprising archival as well as contemporaneous multi-wavelength data from the radio to the VHE band. The SEDs of known VHE γ-ray sources in low flux states matches well the SED of the stacked blazar sample. (orig.)

  14. A Novel Dual-Band Rectenna for Ambient RF Energy Harvesting at GSM 900 MHz and 1800 MHz

    Directory of Open Access Journals (Sweden)

    Dinh Khanh Ho

    2017-06-01

    Full Text Available This paper presents a novel dual-band rectenna for RF energy harvesting system. This rectenna is created from a dual-band antenna and a dual-band rectifier which operates at GSM bands (900 MHz and 1800 MHz. The printed monopole antenna is miniaturized by two meander-lines. The received signal from the receiving antenna is rectified by a voltage double using Schottky diode SMS-7630. The rectifier is optimized for low input power level of -20dBm using harmonic balance. Prototype is designed and fabricated. The simulation is validated by measurement with power conversion efficiency of 20% and 40.8% (in measurement at the input power level of -20dBm. The proposed rectenna has output voltage from 183-415 mV. From the measured results, this rectenna provides the possibility to harvest the ambient electromagnetic energy for powering low-power electronic devices.

  15. Bulgarian geothermal energy resources - state and perspective

    Energy Technology Data Exchange (ETDEWEB)

    Gramatikov, P S [Faculty of Natural Sciences and Mathematics, Dept. of Physical Engineering, South West Univ. ` Neofit Rilsky` , Blagoevgrad (Bulgaria)

    1997-12-01

    As special attention is paid to geothermal energy because the geothermal sources are distributed all over the territory of Bulgaria. Governmental incentives for initiating national action programs for energy efficiency, new renewable sources and the environment as well as educational activities are particularly important. The energy sector, as any other sector of the national economy, is currently undergoing considerable changes on its way to market relations, primarily connected to determining the role of the state as well as the form of ownership. The state energy policy is based on a long - term energy strategy complying with the natural conditions of the country, the expected macro - economic development, the geopolitical situation and regional development of energy cooperation with neighboring and closely situated countries. Limited reserves of fossil fuels, increased local and global environmental risks and recent technological achievements have straightened the global importance of renewable sources of thermal and electric energy. This is even more relevant for Bulgaria with small fossil fuel reserves (lignite) to be nearly exhausted and the environment notably polluted. Concerning local renewable sources of thermal energy and electricity, it is necessary to re-estimate their strategic role, to complete the input data for the resources, also to establish national programs supported by research and educational activities and international cooperation. (orig./AKF)

  16. Scaling Universality between Band Gap and Exciton Binding Energy of Two-Dimensional Semiconductors

    Science.gov (United States)

    Jiang, Zeyu; Liu, Zhirong; Li, Yuanchang; Duan, Wenhui

    2017-06-01

    Using first-principles G W Bethe-Salpeter equation calculations and the k .p theory, we unambiguously show that for two-dimensional (2D) semiconductors, there exists a robust linear scaling law between the quasiparticle band gap (Eg) and the exciton binding energy (Eb), namely, Eb≈Eg/4 , regardless of their lattice configuration, bonding characteristic, as well as the topological property. Such a parameter-free universality is never observed in their three-dimensional counterparts. By deriving a simple expression for the 2D polarizability merely with respect to Eg, and adopting the screened hydrogen model for Eb, the linear scaling law can be deduced analytically. This work provides an opportunity to better understand the fantastic consequence of the 2D nature for materials, and thus offers valuable guidance for their property modulation and performance control.

  17. Broad band energy distribution of UV-bright BL Lac objects

    International Nuclear Information System (INIS)

    Maraschi, L.; Tanzi, E.G.; Treves, A.

    1984-01-01

    IUE satellite data in the 1200-2000 and 1900-3200 A intervals of BL Lac objects are analyzed in terms of two discernible groups. A total of 25 BL Lac objects were observed, with differences between groups displayed in terms of the power slope of the energy of the UV emissions, i.e., slopes of 1 and 2. Comparisons of the spectra with those of quasars showed that quasars have a small spectral index in the 1000-6000 A band and no correlation exists between the spectral index and UV flux of the BL Lac objects. The comparisons underscore the lack of a thermal component for BL Lac objects. Steep spectral components in both BL Lac objects and highly polarized quasars emissions could both be due to synchrotron emission. Compton scattering of relativistic electrons off synchrotron photons could produce the X ray emissions. 44 references

  18. Broad band energy distribution of UV-bright BL Lac objects

    Energy Technology Data Exchange (ETDEWEB)

    Maraschi, L.; Tanzi, E.G.; Treves, A.

    1984-01-01

    IUE satellite data in the 1200-2000 and 1900-3200 A intervals of BL Lac objects are analyzed in terms of two discernible groups. A total of 25 BL Lac objects were observed, with differences between groups displayed in terms of the power slope of the energy of the UV emissions, i.e., slopes of 1 and 2. Comparisons of the spectra with those of quasars showed that quasars have a small spectral index in the 1000-6000 A band and no correlation exists between the spectral index and UV flux of the BL Lac objects. The comparisons underscore the lack of a thermal component for BL Lac objects. Steep spectral components in both BL Lac objects and highly polarized quasars emissions could both be due to synchrotron emission. Compton scattering of relativistic electrons off synchrotron photons could produce the X ray emissions. 44 references.

  19. Forbidden energy band gap in diluted a-Ge1−xSix:N films

    International Nuclear Information System (INIS)

    Guarneros, C.; Rebollo-Plata, B.; Lozada-Morales, R.; Espinosa-Rosales, J.E.; Portillo-Moreno, J.; Zelaya-Angel, O.

    2012-01-01

    By means of electron gun evaporation Ge 1−x Si x :N thin films, in the entire range 0 ≤ x ≤ 1, were prepared on Si (100) and glass substrates. The initial vacuum reached was 6.6 × 10 −4 Pa, then a pressure of 2.7 × 10 −2 Pa of high purity N 2 was introduced into the chamber. The deposition time was 4 min. Crucible-substrate distance was 18 cm. X-ray diffraction patterns indicate that all the films were amorphous (a-Ge 1−x Si x :N). The nitrogen concentration was of the order of 1 at% for all the films. From optical absorption spectra data and by using the Tauc method the energy band gap (E g ) was calculated. The Raman spectra only reveal the presence of Si-Si, Ge-Ge, and Si-Ge bonds. Nevertheless, infrared spectra demonstrate the existence of Si-N and Ge-N bonds. The forbidden energy band gap (E g ) as a function of x in the entire range 0 ≤ x ≤ 1 shows two well defined regions: 0 ≤ x ≤ 0.67 and 0.67 ≤ x ≤ 1, due to two different behaviors of the band gap, where for x > 0.67 exists an abruptly change of E g (x). In this case E g (x) versus x is different to the variation of E g in a-Ge 1−x Si x and a-Ge 1−x Si x :H. This fact can be related to the formation of Ge 3 N 4 and GeSi 2 N 4 when x ≤ 0.67, and to the formation of Si 3 N 4 and GeSi 2 N 4 for 0.67 ≤ x. - Highlights: ► Nitrogen doped amorphous Ge 1-x Si x thin films are grown by electron gun technique. ► Nitrogen atoms on E g of the a-Ge 1-x Si x films in the 0 £ x £ 1 range are analyzed. ► Variation in 0 £ x £ 1 range shows a warped change of E g in 1.0 – 3.6 eV range. ► The change in E g (x) behavior when x ∼ 0.67 was associated with Ge 2 SiN 4 presence.

  20. Pressure-induced magneto-structural transition in iron via a modified solid-state nudged elastic band method

    Science.gov (United States)

    Zarkevich, Nikolai A.; Johnson, Duane D.

    2015-03-01

    Materials under pressure may exhibit critical electronic and structural transitions that affect equation of states, as known for superconductors and the magneto-structural transformations of iron with both geophysical and planetary implications. While experiments often use constant-pressure (diamond-anvil cell, DAC) measurements, many theoretical results address a constant-volume transitions, which avoid issues with magnetic collapse but cannot be directly compared to experiment. We establish a modified solid-state nudge elastic band (MSS-NEB) method to handle magnetic systems that may exhibit moment (and volume) collapse during transformation. We apply it to the pressure-induced transformation in iron between the low-pressure body-centered cubic (bcc) and the high-pressure hexagonal close-packed (hcp) phases, find the bcc-hcp equilibrium coexistence pressure and a transitional pathway, and compare to shock and DAC experiments. We use methods developed with support by the U.S. Department of Energy (DE-FG02-03ER46026 and DE-AC02-07CH11358). Ames Laboratory is operated for the DOE by Iowa State University under contract DE-AC02-07CH11358.

  1. Ti α - ω phase transformation and metastable structure, revealed by the solid-state nudged elastic band method

    Science.gov (United States)

    Zarkevich, Nikolai; Johnson, Duane D.

    Titanium is on of the four most utilized structural metals, and, hence, its structural changes and potential metastable phases under stress are of considerable importance. Using DFT+U combined with the generalized solid-state nudged elastic band (SS-NEB) method, we consider the pressure-driven transformation between Ti α and ω phases, and find an intermediate metastable body-centered orthorhombic (bco) structure of lower density. We verify its stability, assess the phonons and electronic structure, and compare computational results to experiment. Interestingly, standard density functional theory (DFT) yields the ω phase as the Ti ground state, in contradiction to the observed α phase at low pressure and temperature. We correct this by proper consideration of the strongly correlated d-electrons, and utilize DFT+U method in the SS-NEB to obtain the relevant transformation pathway and structures. We use methods developed with support by the U.S. Department of Energy (DE-FG02-03ER46026 and DE-AC02-07CH11358). Ames Laboratory is operated for the DOE by Iowa State University under Contract DE-AC02-07CH11358.

  2. Magneto-structural transformations via a solid-state nudged elastic band method: Application to iron under pressure

    International Nuclear Information System (INIS)

    Zarkevich, N. A.; Johnson, D. D.

    2015-01-01

    We extend the solid-state nudged elastic band method to handle a non-conserved order parameter, in particular, magnetization, that couples to volume and leads to many observed effects in magnetic systems. We apply this formalism to the well-studied magneto-volume collapse during the pressure-induced transformation in iron—from ferromagnetic body-centered cubic (bcc) austenite to hexagonal close-packed (hcp) martensite. We find a bcc-hcp equilibrium coexistence pressure of 8.4 GPa, with the transition-state enthalpy of 156 meV/Fe at this pressure. A discontinuity in magnetization and coherent stress occurs at the transition state, which has a form of a cusp on the potential-energy surface (yet all the atomic and cell degrees of freedom are continuous); the calculated pressure jump of 25 GPa is related to the observed 25 GPa spread in measured coexistence pressures arising from martensitic and coherency stresses in samples. Our results agree with experiments, but necessarily differ from those arising from drag and restricted parametrization methods having improperly constrained or uncontrolled degrees of freedom

  3. Changes in the surface electronic states of semiconductor fine particles induced by high energy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaki, Tetsuya; Asai, Keisuke; Ishigure, Kenkichi [Tokyo Univ. (Japan); Shibata, Hiromi

    1997-03-01

    The changes in the surface electronic states of Q-sized semiconductor particles in Langmuir-Blodgett (LB) films, induced by high energy ion irradiation, were examined by observation of ion induced emission and photoluminescence (PL). Various emission bands attributed to different defect sites in the band gap were observed at the initial irradiation stage. As the dose increased, the emissions via the trapping sites decreased in intensity while the band-edge emission developed. This suggests that the ion irradiation would remove almost all the trapping sites in the band gap. The low energy emissions, which show a multiexponential decay, were due to a donor-acceptor recombination between the deeply trapped carriers. It was found that the processes of formation, reaction, and stabilization of the trapping sites would predominantly occur under the photooxidizing conditions. (author)

  4. The effect of spin-orbit coupling in band structure and edge states of bilayer graphene

    Energy Technology Data Exchange (ETDEWEB)

    Sahdan, Muhammad Fauzi; Darma, Yudi, E-mail: yudi@fi.itb.ac.id [Department of Physics, InstitutTeknologi Bandung, Jalan Ganesa 10, Bandung 40132 (Indonesia)

    2015-04-16

    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 bilayer grapheme and also its edge states by using this model with analytical approach. The results of our calculation show that the gap opening occurs at K and K’ point in bilayer graphene.In addition, a pair of gapless edge modes occurs both in the zigzag and arm-chair configurations are no longer exist. There are gap created at the edge even though thery are very small.

  5. UNITED STATES DEPARTMENT OF TRANSPORTATION GLOBAL POSITIONING SYSTEM (GPS) ADJACENT BAND COMPATIBILITY ASSESSMENT

    Science.gov (United States)

    2018-04-01

    The goal of the U.S. Department of Transportation (DOT) Global Positioning System (GPS) Adjacent Band Compatibility Assessment is to evaluate the maximum transmitted power levels of adjacent band radiofrequency (RF) systems that can be tolerated by G...

  6. CdS_xTe_1_-_x ternary semiconductors band gaps calculation using ground state and GW approximations

    International Nuclear Information System (INIS)

    Kheloufi, Nawal; Bouzid, Abderrazak

    2016-01-01

    We present band gap calculations of zinc-blende ternary CdS_xTe_1_-_x semiconductors within the standard DFT and quasiparticle calculations employing pseudopotential method. The DFT, the local density approximation (LDA) and the Generalized Gradient Approximation (GGA) based calculations have given very poor results compared to experimental data. The quasiparticle calculations have been investigated via the one-shot GW approximation. The present paper discuses and confirms the effect of inclusion of the semicore states in the cadmium (Cd) pseudopotential. The obtained GW quasiparticle band gap using Cd"+"2"0 pseudopotential has been improved compared to the obtained results from the available pseudopotential without the treatment of semicore states. Our DFT and quasiparticle band gap results are discussed and compared to the available theoretical calculations and experimental data. - Graphical abstract: Band gaps improvement concerning the binary and ternary alloys using the GW approximation and Cd"2"0"+ pseudopotential with others levels of approximations (the LDA and GGA approximation employing the Cd"1"2"+ and the LDA within Cd"2"0"+ pseudopotential). - Highlights: • The direct Γ- Γ and indirect Γ- X and Γ- L bands gaps show a nonlinear behavior when S content is enhanced. • The quasiparticle band gap result for the investigated semiconductors is improved using the GW approximation. • All CdS_xTe_1_-_x compounds in all compositions range from 0 to 1 are direct band gap semiconductors.

  7. Investigation of an energy-gap model for photoacoustic O2A-band spectra: H2O calibration near 7180 cm−1

    International Nuclear Information System (INIS)

    Vess, E.M.; Anderson, C.N.; Awadalla, V.E.; Estes, E.J.; Jeon, C.; Wallace, C.J.; Hu, X.F.; Havey, D.K.

    2012-01-01

    Highlights: ► We investigate an energy transfer model for photoacoustic measurements of the O 2 A-band. ► We measure the response of a photoacoustic spectrometer for known quantities of H 2 O and O 2 . ► We fit multiple theoretical spectral line profiles to the data. ► We bind the relative uncertainty of the energy transfer model to less than 1%. ► We demonstrate that speed-dependence is an important line shape effect for these experiments. - Abstract: A photoacoustic spectrometer is used to evaluate the accuracy of an energy-gap model for collisional energy transfer. For photoacoustic measurements involving the b 1 Σ g + ←X 3 Σ g - transition of molecular oxygen the conversion of photon energy to thermal energy is inefficient and proceeds through the a 1 Δ g state. This results in attenuation of the photoacoustic signal. The magnitude of the attenuation can be predicted with an energy-gap model whose accuracy has been previously confirmed to within 3 ± 5%. However, this prior result does not rule out incomplete rotational relaxation of O 2 in the a 1 Δ g state. In this study, high-resolution spectra of H 2 O in air are used to calibrate the photoacoustic spectrometer. This work binds the relative uncertainty in the energy-gap relaxation factor for O 2 A-band photoacoustic signals to be approximately 1%. During one acoustic cycle, this result implies negligible collisional relaxation to the X 3 Σ g - state of O 2 and nearly complete collisional relaxation to the a 1 Δ g state.

  8. Coral transcriptome and bacterial community profiles reveal distinct Yellow Band Disease states in Orbicella faveolata

    KAUST Repository

    Closek, Collin J.

    2014-06-20

    Coral diseases impact reefs globally. Although we continue to describe diseases, little is known about the etiology or progression of even the most common cases. To examine a spectrum of coral health and determine factors of disease progression we examined Orbicella faveolata exhibiting signs of Yellow Band Disease (YBD), a widespread condition in the Caribbean. We used a novel combined approach to assess three members of the coral holobiont: the coral-host, associated Symbiodinium algae, and bacteria. We profiled three conditions: (1) healthy-appearing colonies (HH), (2) healthy-appearing tissue on diseased colonies (HD), and (3) diseased lesion (DD). Restriction fragment length polymorphism analysis revealed health state-specific diversity in Symbiodinium clade associations. 16S ribosomal RNA gene microarrays (PhyloChips) and O. faveolata complimentary DNA microarrays revealed the bacterial community structure and host transcriptional response, respectively. A distinct bacterial community structure marked each health state. Diseased samples were associated with two to three times more bacterial diversity. HD samples had the highest bacterial richness, which included components associated with HH and DD, as well as additional unique families. The host transcriptome under YBD revealed a reduced cellular expression of defense- and metabolism-related processes, while the neighboring HD condition exhibited an intermediate expression profile. Although HD tissue appeared visibly healthy, the microbial communities and gene expression profiles were distinct. HD should be regarded as an additional (intermediate) state of disease, which is important for understanding the progression of YBD. © 2014 International Society for Microbial Ecology. All rights reserved.

  9. Resting-state theta band connectivity and graph analysis in generalized social anxiety disorder.

    Science.gov (United States)

    Xing, Mengqi; Tadayonnejad, Reza; MacNamara, Annmarie; Ajilore, Olusola; DiGangi, Julia; Phan, K Luan; Leow, Alex; Klumpp, Heide

    2017-01-01

    Functional magnetic resonance imaging (fMRI) resting-state studies show generalized social anxiety disorder (gSAD) is associated with disturbances in networks involved in emotion regulation, emotion processing, and perceptual functions, suggesting a network framework is integral to elucidating the pathophysiology of gSAD. However, fMRI does not measure the fast dynamic interconnections of functional networks. Therefore, we examined whole-brain functional connectomics with electroencephalogram (EEG) during resting-state. Resting-state EEG data was recorded for 32 patients with gSAD and 32 demographically-matched healthy controls (HC). Sensor-level connectivity analysis was applied on EEG data by using Weighted Phase Lag Index (WPLI) and graph analysis based on WPLI was used to determine clustering coefficient and characteristic path length to estimate local integration and global segregation of networks. WPLI results showed increased oscillatory midline coherence in the theta frequency band indicating higher connectivity in the gSAD relative to HC group during rest. Additionally, WPLI values positively correlated with state anxiety levels within the gSAD group but not the HC group. Our graph theory based connectomics analysis demonstrated increased clustering coefficient and decreased characteristic path length in theta-based whole brain functional organization in subjects with gSAD compared to HC. Theta-dependent interconnectivity was associated with state anxiety in gSAD and an increase in information processing efficiency in gSAD (compared to controls). Results may represent enhanced baseline self-focused attention, which is consistent with cognitive models of gSAD and fMRI studies implicating emotion dysregulation and disturbances in task negative networks (e.g., default mode network) in gSAD.

  10. Graphene oxide quantum dot-sensitized porous titanium dioxide microsphere: Visible-light-driven photocatalyst based on energy band engineering.

    Science.gov (United States)

    Zhang, Yu; Qi, Fuyuan; Li, Ying; Zhou, Xin; Sun, Hongfeng; Zhang, Wei; Liu, Daliang; Song, Xi-Ming

    2017-07-15

    We report a novel graphene oxide quantum dot (GOQD)-sensitized porous TiO 2 microsphere for efficient photoelectric conversion. Electro-chemical analysis along with the Mott-Schottky equation reveals conductivity type and energy band structure of the two semiconductors. Based on their energy band structures, visible light-induced electrons can transfer from the p-type GOQD to the n-type TiO 2 . Enhanced photocurrent and photocatalytic activity in visible light further confirm the enhanced separation of electrons and holes in the nanocomposite. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Systematic study of β-band and correlation with g- band using power law and soft rotor formula

    International Nuclear Information System (INIS)

    Katoch, Vikas; Kaushik, Reetu; Sharma, S.; Gupta, J.B.

    2014-01-01

    The nuclear structure of even Z even N medium mass transitional nuclei consist of ground state band, K π =0 1 β-band, K π =2 1 γ- band and other higher bands. As we move away from closed shell, energy levels are low lying from spherical to deformed nuclei and energy deviated from ideal rotor behavior. The energy of these transitional nuclei in ground band can also be studied using Bohr Mottelson energy expression, Soft Rotor Formula (SRF), Power Law (PL) etc. Recently, Gupta et al. (2013) modified SRF for non zero band head K π =2 1 γ-band and reproduced the level energies. Here same formula applied for K π =0 1 β-band and the level energies are reproduced and compared with experimental energies. The power law is also used for recalculation of level energies and for useful comparison

  12. State of the energy in Lebanon

    International Nuclear Information System (INIS)

    Chehab, Said; Matar Toni

    1998-01-01

    The article describes the state of the energy in Lebanon. In 1996, Lebanon consumed 4647 Ktoe as a primary energy. 97% of this energy is imported mainly polluting oil products: 1623 Ktons fuel-oil, 1379 Ktons gasoline, 930 Ktons diesel, 200 Ktons coal, 124 Ktons LPG, 107 Ktons jet-fuel/Kerosene, 109 Ktons Asphaltic products. The remaining 3% of the energy consumption is renewable energy. As for production, the state owns two refineries which are not used anymore. The year 2000 plan includes an expansion project for the Tripoli refinery and an alternative plan for the Zahrani refinery. These refineries require a total investment in order to reach a production capacity of 50000 barrels a day. The article is a description of the pollution type sources and location in Lebanon. The combustion of the total energy produces yearly more than 15 Ktons of dust, 85 Ktons of SO 2 , 40 Ktons of NOX and 3500 Ktons of CO 2 . Another risk of pollution is due to spilling oil along the Lebanese coast which represents a potential oil spill hazard, with a serious impact on marine and coastal ecosystem. The paper presents also a proposed management schemes of energy policy , control and monitoring options. In addition to the energy balance in 93/94; the consumption of oil products in 93/94/96; oil products importations in 93/96; electricity consumption in 96; ventilation of thermal and hydraulic electricity production in 95/96; estimated inventory of emissions of selected pollutants to air in Lebanon in 93 and 2010; maximum permissible air pollutants in Lebanon; storage capacity of major petroleum importers

  13. Valence-band splitting energies in wurtzite InP nanowires: Photoluminescence spectroscopy and ab initio calculations

    Science.gov (United States)

    Gadret, E. G.; Dias, G. O.; Dacal, L. C. O.; de Lima, M. M., Jr.; Ruffo, C. V. R. S.; Iikawa, F.; Brasil, M. J. S. P.; Chiaramonte, T.; Cotta, M. A.; Tizei, L. H. G.; Ugarte, D.; Cantarero, A.

    2010-09-01

    We investigated experimentally and theoretically the valence-band structure of wurtzite InP nanowires. The wurtzite phase, which usually is not stable for III-V phosphide compounds, has been observed in InP nanowires. We present results on the electronic properties of these nanowires using the photoluminescence excitation technique. Spectra from an ensemble of nanowires show three clear absorption edges separated by 44 meV and 143 meV, respectively. The band edges are attributed to excitonic absorptions involving three distinct valence-bands labeled: A, B, and C. Theoretical results based on “ab initio” calculation gives corresponding valence-band energy separations of 50 meV and 200 meV, respectively, which are in good agreement with the experimental results.

  14. Recoil-distance lifetime measurements of the ground-state band in 164Dy, 170Er, and 174Yb

    International Nuclear Information System (INIS)

    Sie, S.H.; Gebbie, D.W.

    1977-06-01

    Mean-lives of the 4 + , 6 + and 8 + levels of the ground-state band in 164 Dy, 170 Er and 174 Yb have been measured by the recoil-distance technique following multiple Coulomb excitation with 32 S projectiles of energy 120-140 MeV. The gamma-rays were detected in coincidence with backscattered particles. The results are compared with theoretical predictions of the adiabatic rotor model. The 6 + and 8 + lifetimes in 164 Dy are found to correspond to a slight reduction in B(E2) values over the rotational model prediction, while for for the 4 + state a 12% reduction was observed. In 170 Er and 174 Yb the lifetimes are consistent with rotational model predictions with a slight enhancement of B(E2) values at higher spins. Comparison with other results from Doppler broadened lineshape analysis confirms the need to adjust the electronic stopping powers of Northcliffe and Schilling in the lineshape calculations. (Author)

  15. Energy partnership: China and the Gulf states

    International Nuclear Information System (INIS)

    Bahgat, G.

    2005-01-01

    One of the most significant developments in the global energy market in the last several years has been China's skyrocketing demand for energy. In 1993, China became a net oil importer for the first time in its history and in 2003 replaced Japan as the world's second-largest oil importer (after the United States). The country needs more energy to maintain its spectacular economic performance. This study examines China's attempts to satisfy its growing needs for oil and natural gas by increasing imports from Russia and Central Asia/Caspian Sea region. The analysis suggests that despite growing cooperation between the two sides, the Gulf region is likely to satisfy most of China's hydrocarbons needs. Energy partnership between China and the Gulf has already started and is likely to be consolidated over the next few decades. The study also argues that this growing partnership between China and the Gulf should not be seen as a threat to any third party. The global energy market is well-integrated. Energy policy should not be seen in zero-sum terms. A China-Gulf partnership will benefit both sides and contribute to the stability of global energy markets. (author)

  16. Hydrostatic pressure and conduction band non-parabolicity effects on the impurity binding energy in a spherical quantum dot

    International Nuclear Information System (INIS)

    Sivakami, A.; Mahendran, M.

    2010-01-01

    The binding energy of a shallow hydrogenic impurity in a spherical quantum dot under hydrostatic pressure with square well potential is calculated using a variational approach within the effective mass approximation. The effect of conduction band non-parabolicity on these energies is also estimated. The binding energy is computed for GaAs spherical quantum dot as a function of dot size, hydrostatic pressure both in the presence and absence of the band non-parabolicity effect. Our results show that (i) the hydrostatic pressure increases the impurity binding energy when dot radius increases for a given pressure, (ii) the hydrostatic pressure with the band non-parabolicity effect effectively increases the binding energy such that the variation is large for smaller dots and (iii) the maximum contribution by the non-parabolicity effect is about 15% for narrow dots. Our results are in good agreement with Perez-Merchancano et al. [J. Phys. Condens. Matter 19 (2007) 026225] who have not considered the conduction band non-parabolicity effect.

  17. First excited states in doubly-odd 110Sb: Smooth band termination in the A ∼ 110 region

    International Nuclear Information System (INIS)

    Lane, G.J.; Fossan, D.B.; Thorslund, I.

    1996-01-01

    Excited states have been identified for the first time in 110 Sb in a comprehensive series of γ-spectroscopy experiments, including recoil-mass and neutron-field measurements. Three high-spin decoupled bands with configurations based on 2p-2h excitations across the Z = 50 shell gap, are observed to show the features of smooth band termination, the first such observation in an odd-odd nucleus. The yrast intruder band has been connected to the low spin levels and is tentatively identified up to its predicred termination at I π = (45 + ). Detailed configuration assignments are made through comparison with configuration-dependent cranked Nilsson-Strutinsky calculations; excellent agreement with experiment is obtained. The systematic occurrence of smoothly terminating bands in the neighboring isotopes is discussed

  18. Interfacial chemical bonding state and band alignment of CaF2/hydrogen-terminated diamond heterojunction

    International Nuclear Information System (INIS)

    Liu, J. W.; Liao, M. Y.; Cheng, S. H.; Imura, M.; Koide, Y.

    2013-01-01

    CaF 2 films are deposited on hydrogen-terminated diamond (H-diamond) by a radio-frequency sputter-deposition technique at room temperature. Interfacial chemical bonding state and band alignment of CaF 2 /H-diamond heterojunction are investigated by X-ray photoelectron spectroscopy. It is confirmed that there are only C-Ca bonds at the CaF 2 /H-diamond heterointerface. Valence and conductance band offsets of the CaF 2 /H-diamond heterojunciton are determined to be 3.7 ± 0.2 and 0.3 ± 0.2 eV, respectively. It shows a type I straddling band configuration. The large valence band offset suggests advantage of the CaF 2 /H-diamond heterojunciton for the development of high power and high frequency field effect transistors.

  19. State Clean Energy Policies Analysis (SCEPA). State Policy and the Pursuit of Renewable Energy Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Oteri, Frank [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tegen, Suzanne [National Renewable Energy Lab. (NREL), Golden, CO (United States); Doris, Elizabeth [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2010-02-01

    Future manufacturing of renewable energy equipment in the United States provides economic development opportunities for state and local communities. However, demand for the equipment is finite, and opportunities are limited. U.S. demand is estimated to drive total annual investments in renewable energy equipment to $14-$20 billion by 2030. Evidence from leading states in renewable energy manufacturing suggests that economic development strategies that target renewable energy sector needs by adapting existing policies attract renewable energy manufacturing more than strategies that create new policies. Literature suggests that the states that are most able to attract direct investment and promote sustained economic development can leverage diverse sets of durable assets—like human capital and modern infrastructure–as well as low barriers to market entry. State marketing strategies for acquiring renewable energy manufacturers are likely best served by an approach that: (1) is multi-faceted and long-term, (2) fits within existing broad-based economic development strategies, (3) includes specific components such as support for renewable energy markets and low barriers to renewable energy deployment, and (4) involves increased differentiation by leveraging existing assets when applicable.

  20. State Clean Energy Policies Analysis (SCEPA): State Policy and the Pursuit of Renewable Energy Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, E.; Oteri, F.; Tegen, S.; Doris, E.

    2010-02-01

    Future manufacturing of renewable energy equipment in the United States provides economic development opportunities for state and local communities. However, demand for the equipment is finite, and opportunities are limited. U.S. demand is estimated to drive total annual investments in renewable energy equipment to $14-$20 billion by 2030. Evidence from leading states in renewable energy manufacturing suggests that economic development strategies that target renewable energy sector needs by adapting existing policies attract renewable energy manufacturing more than strategies that create new policies. Literature suggests that the states that are most able to attract direct investment and promote sustained economic development can leverage diverse sets of durable assets--like human capital and modern infrastructure--as well as low barriers to market entry. State marketing strategies for acquiring renewable energy manufacturers are likely best served by an approach that: (1) is multi-faceted and long-term, (2) fits within existing broad-based economic development strategies, (3) includes specific components such as support for renewable energy markets and low barriers to renewable energy deployment, and (4) involves increased differentiation by leveraging existing assets when applicable.

  1. Inelastic neutron excitation of the ground state rotational band of 238U

    International Nuclear Information System (INIS)

    Guenther, P.; Smith, A.

    1975-01-01

    Cross sections for the neutron excitation of the 2+(45 keV), 4+(148 keV) and 6+(308 keV) states in 238 U were measured to incident energies of approximately 3.0 MeV. The experimental resolution was sufficient to resolve these components throughout the measured energy range. Particular attention was given to energies near threshold and in the few MeV range where direct reaction contributions were appreciable. The experimental results were compared with theoretical estimates based upon statistical and coupled-channel models deduced from comprehensive studies of neutron scattering from heavy-rotational-deformed nuclei. An evaluated inelastic scattering data set was derived from the present experimental and calculational results and previously reported experimental values and compared with respective values from the ENDF-IV file. 4 figures

  2. State Energy Program Results: More Projects That Work

    Energy Technology Data Exchange (ETDEWEB)

    1998-12-01

    A Summary of Success stories of the State Energy Programs. The goal of the State Energy Program is to strengthen the capabilities of States to promote energy efficiency and to adopt renewable energy technologies, thereby helping the nation save energy and realize a stronger economy, cleaner environment, and a more secure future.

  3. Nuclear energy and the constitutional state

    International Nuclear Information System (INIS)

    Saladin, P.

    1984-01-01

    This article puts the main emphasis on the problems of the constitutional principles of democracy, federalism, peaceful living together of peoples and constitutional state, i.e. problems caused by the development of nuclear energy. The fact that these problems are explained by way of the example of Switzerland, does not reduce the validity of the findings also for the German constitutional system, since the problems are identical and comparable. A long-term goal is a state theory which helps to define the aims and tasks of the state under technical, social, economic and cultural conditions of the end of the 20th and perhaps of the 21st century. Nuclear technology challenges the modern Western state and puts to the test the firmness of its legitimacy basis and the efficiency of its principles. It was conceived in a time which is separated from the present by technological revolutions. Safeguarding of humanity is aim and obligation of the modern constitutional state; the constitutional state stipulates the rules of conduct and, if the state remains true to its claim, it sets the procedures and the organization which give due priority order to the development of modern technology. (orig./HSCH) [de

  4. q-Gamow states for intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Plastino, A. [La Plata National University and Argentina' s National Research Council, (IFLP-CCT-CONICET)-C. C. 727, 1900 La Plata (Argentina); Rocca, M.C., E-mail: mariocarlosrocca@gmail.com [La Plata National University and Argentina' s National Research Council, (IFLP-CCT-CONICET)-C. C. 727, 1900 La Plata (Argentina); Ferri, G.L. [Fac. de C. Exactas, National University La Pampa, Peru y Uruguay, Santa Rosa, La Pampa (Argentina); Zamora, D.J. [La Plata National University and Argentina' s National Research Council, (IFLP-CCT-CONICET)-C. C. 727, 1900 La Plata (Argentina)

    2016-11-15

    In a recent paper Plastino and Rocca (2016) [18] we have demonstrated the possible existence of Tsallis' q-Gamow states. Now, accelerators' experimental evidence for Tsallis' distributions has been ascertained only at very high energies. Here, instead, we develop a different set of q-Gamow states for which the associated q-Breit–Wigner distribution could easily be found at intermediate energies, for which accelerators are available at many locations. In this context, it should be strongly emphasized Vignat and Plastino (2009) [2] that, empirically, one never exactly and unambiguously “detects” pure Gaussians, but rather q-Gaussians. A prediction is made via Eq. (3.4).

  5. The United States toward Energy Independence?

    International Nuclear Information System (INIS)

    Nardon, Laurence

    2013-01-01

    The U.S.'s exploitation of 'unconventional' domestic oil reserves is reviving its economy. It will also have effects on the country's energy independence and thus its geopolitical position. While it is unlikely that the relationship between Washington and the Middle East region will be fundamentally altered, the U.S.'s relationships with China, Russia, and Europe could be affected. The United States will have to incorporate these changes into its global strategies

  6. Decay of superdeformed bands

    International Nuclear Information System (INIS)

    Carpenter, M.P.; Khoo, T.L.; Lauritsen, T.

    1995-01-01

    One of the major challenges in the study of superdeformation is to directly connect the large number of superdeformed bands now known to the yrast states. In this way, excitation energies, spins and parities can be assigned to the levels in the second well which is essential to establish the collective and single-particle components of these bands. This paper will review some of the progress which has been made to understand the decay of superdeformed bands using the new arrays including the measurement of the total decay spectrum and the establishment of direct one-step decays from the superdeformed band to the yrast line in 194 Hg. 42 refs., 5 figs

  7. 6. State energy balance - 1978/1987 - Minas Gerais, Brazil

    International Nuclear Information System (INIS)

    1989-05-01

    The energetic plan of Minas Gerais state and the steps such as energy balance, state potential energy identification, social and economic analysis, energetic flux, energy consumption is presented. (L.J.C.)

  8. Toxicity of metal oxide nanoparticles in Escherichia coli correlates with conduction band and hydration energies.

    Science.gov (United States)

    Kaweeteerawat, Chitrada; Ivask, Angela; Liu, Rong; Zhang, Haiyuan; Chang, Chong Hyun; Low-Kam, Cecile; Fischer, Heidi; Ji, Zhaoxia; Pokhrel, Suman; Cohen, Yoram; Telesca, Donatello; Zink, Jeffrey; Mädler, Lutz; Holden, Patricia A; Nel, Andre; Godwin, Hilary

    2015-01-20

    Metal oxide nanoparticles (MOx NPs) are used for a host of applications, such as electronics, cosmetics, construction, and medicine, and as a result, the safety of these materials to humans and the environment is of considerable interest. A prior study of 24 MOx NPs in mammalian cells revealed that some of these materials show hazard potential. Here, we report the growth inhibitory effects of the same series of MOx NPs in the bacterium Escherichia coli and show that toxicity trends observed in E. coli parallel those seen previously in mammalian cells. Of the 24 materials studied, only ZnO, CuO, CoO, Mn2O3, Co3O4, Ni2O3, and Cr2O3 were found to exert significant growth inhibitory effects; these effects were found to relate to membrane damage and oxidative stress responses in minimal trophic media. A correlation of the toxicological data with physicochemical parameters of MOx NPs revealed that the probability of a MOx NP being toxic increases as the hydration enthalpy becomes less negative and as the conduction band energy approaches those of biological molecules. These observations are consistent with prior results observed in mammalian cells, revealing that mechanisms of toxicity of MOx NPs are consistent across two very different taxa. These results suggest that studying nanotoxicity in E. coli may help to predict toxicity patterns in higher organisms.

  9. Voltage effect in PTCR ceramics: Calculation by the method of tilted energy band

    International Nuclear Information System (INIS)

    Fang Chao; Zhou Dongxiang; Gong Shuping

    2010-01-01

    A numerical model for the calculation of the electrical characteristics of donor-doped BaTiO 3 semiconducting ceramics is suggested. This paper established a differential equation about electron level on the base of Poisson equation, and solved the equation with Runge-Kutta method. Under extra electric field, electrical characteristics have been calculated by the method of tilted energy band. We have quantitatively computed the positive temperature coefficient of resistivity (PTCR) behavior of donor-doped BaTiO 3 semiconducting ceramics and its voltage effect, and further obtained non-linear current-voltage characteristics with different grain sizes at different temperature. The results pointed out that the resistance jumping is reduced with increasing electric field applied; current and voltage relation follows Ohm's law below Curie temperature, and exhibits strong non-linear above Curie temperature; the non-linear coefficient shows a maximum value at temperature the resistivity reaches maximum and with grain size closed to depletion region width. The results are compared with experimental data.

  10. Renewable Energy Atlas of the United States

    Energy Technology Data Exchange (ETDEWEB)

    Kuiper, J. [Environmental Science Division; Hlava, K. [Environmental Science Division; Greenwood, H. [Environmentall Science Division; Carr, A. [Environmental Science Division

    2013-12-13

    The Renewable Energy Atlas (Atlas) of the United States is a compilation of geospatial data focused on renewable energy resources, federal land ownership, and base map reference information. This report explains how to add the Atlas to your computer and install the associated software. The report also includes: A description of each of the components of the Atlas; Lists of the Geographic Information System (GIS) database content and sources; and A brief introduction to the major renewable energy technologies. The Atlas includes the following: A GIS database organized as a set of Environmental Systems Research Institute (ESRI) ArcGIS Personal GeoDatabases, and ESRI ArcReader and ArcGIS project files providing an interactive map visualization and analysis interface.

  11. Mississippi State University Sustainable Energy Research Center

    Energy Technology Data Exchange (ETDEWEB)

    Steele, W. Glenn [Mississippi State Univ., Mississippi State, MS (United States)

    2014-09-26

    The Sustainable Energy Research Center (SERC) project at Mississippi State University included all phases of biofuel production from feedstock development, to conversion to liquid transportation fuels, to engine testing of the fuels. The feedstocks work focused on non-food based crops and yielded an increased understanding of many significant Southeastern feedstocks. an emphasis was placed on energy grasses that could supplement the primary feedstock, wood. Two energy grasses, giant miscanthus and switchgrass, were developed that had increased yields per acre. Each of these grasses was patented and licensed to companies for commercialization. The fuels work focused on three different technologies that each led to a gasoline, diesel, or jet fuel product. The three technologies were microbial oil, pyrolysis oil, and syngas-to liquid-hydrocarbons

  12. A Comprehensive Analysis of the Correlations between Resting-State Oscillations in Multiple-Frequency Bands and Big Five Traits.

    Science.gov (United States)

    Ikeda, Shigeyuki; Takeuchi, Hikaru; Taki, Yasuyuki; Nouchi, Rui; Yokoyama, Ryoichi; Kotozaki, Yuka; Nakagawa, Seishu; Sekiguchi, Atsushi; Iizuka, Kunio; Yamamoto, Yuki; Hanawa, Sugiko; Araki, Tsuyoshi; Miyauchi, Carlos Makoto; Sakaki, Kohei; Nozawa, Takayuki; Yokota, Susumu; Magistro, Daniele; Kawashima, Ryuta

    2017-01-01

    Recently, the association between human personality traits and resting-state brain activity has gained interest in neuroimaging studies. However, it remains unclear if Big Five personality traits are represented in frequency bands (~0.25 Hz) of resting-state functional magnetic resonance imaging (fMRI) activity. Based on earlier neurophysiological studies, we investigated the correlation between the five personality traits assessed by the NEO Five-Factor Inventory (NEO-FFI), and the fractional amplitude of low-frequency fluctuation (fALFF) at four distinct frequency bands (slow-5 (0.01-0.027 Hz), slow-4 (0.027-0.073 Hz), slow-3 (0.073-0.198 Hz) and slow-2 (0.198-0.25 Hz)). We enrolled 835 young subjects and calculated the correlations of resting-state fMRI signals using a multiple regression analysis. We found a significant and consistent correlation between fALFF and the personality trait of extraversion at all frequency bands. Furthermore, significant correlations were detected in distinct brain regions for each frequency band. This finding supports the frequency-specific spatial representations of personality traits as previously suggested. In conclusion, our data highlight an association between human personality traits and fALFF at four distinct frequency bands.

  13. A Comprehensive Analysis of the Correlations between Resting-State Oscillations in Multiple-Frequency Bands and Big Five Traits

    Directory of Open Access Journals (Sweden)

    Shigeyuki Ikeda

    2017-06-01

    Full Text Available Recently, the association between human personality traits and resting-state brain activity has gained interest in neuroimaging studies. However, it remains unclear if Big Five personality traits are represented in frequency bands (~0.25 Hz of resting-state functional magnetic resonance imaging (fMRI activity. Based on earlier neurophysiological studies, we investigated the correlation between the five personality traits assessed by the NEO Five-Factor Inventory (NEO-FFI, and the fractional amplitude of low-frequency fluctuation (fALFF at four distinct frequency bands (slow-5 (0.01–0.027 Hz, slow-4 (0.027–0.073 Hz, slow-3 (0.073–0.198 Hz and slow-2 (0.198–0.25 Hz. We enrolled 835 young subjects and calculated the correlations of resting-state fMRI signals using a multiple regression analysis. We found a significant and consistent correlation between fALFF and the personality trait of extraversion at all frequency bands. Furthermore, significant correlations were detected in distinct brain regions for each frequency band. This finding supports the frequency-specific spatial representations of personality traits as previously suggested. In conclusion, our data highlight an association between human personality traits and fALFF at four distinct frequency bands.

  14. Conduction band-edge d-states in high-k dielectrics due to Jahn-Teller term splittings

    International Nuclear Information System (INIS)

    Lucovsky, G.; Fulton, C.C.; Zhang, Y.; Luning, J.; Edge, L.; Whitten, J.L.; Nemanich, R.J.; Schlom, D.G.; Afanase'v, V.V.

    2005-01-01

    X-ray absorption spectroscopy (XAS) is used to study conduction band edge electronic structure of high-k transition metal (TM) and trivalent lanthanide series rare earth (RE) oxide dielectrics. Empty TM/RE d-states are studied by intra-atomic transitions originating in core level spin-orbit split p-states, and conduction band states are studied in inter-atomic transitions which originate in the oxygen atom 1s core level state. In non-crystalline Zr and Hf silicate alloys, the local bonding symmetry, or crystal field splits these d-states into doubly and triply degenerate features. In nano-crystalline oxides, there are additional d-state splittings due to contributions of more distant neighbors that completely remove d-state degeneracies via the Jahn-Teller effect mechanism. This gives rise to highly localized band edge states that are electronically active in photoconductivity, internal photoemission, and act as bulk traps in metal oxide semiconductor (MOS) devices

  15. Energy Efficiency/Renewable Energy Programs in State Implementation Plans - Guidance Documents

    Science.gov (United States)

    final document that provides guidance to States and local areas on quantifying and including emission reductions from energy efficiency and renewable energy measures in State Implementation Plans (SIPS).

  16. Measurement of Solid-State Optical Refrigeration by Two-Band Differential Luminescence Thermometry

    Science.gov (United States)

    2010-03-01

    high speed transimpedance amplifier that generates an output voltage proportional to the difference in the optical power in bands A and D, i.e., IA...bands in the luminescence spectrum by inter- ference filters, in combination with large core optical fi- bers and highly amplified balanced

  17. Electron and hole states in quantum dot quantum wells within a spherical eight-band model

    NARCIS (Netherlands)

    Pokatilov, E.P.; Fonoberov, V.A.; Fomin, V.; Devreese, J.T.

    2001-01-01

    In order to study heterostructures composed both of materials with strongly different parameters and of materials with narrow band gaps, we have developed an approach [E. P. Pokatilov [etal], Phys. Rev. B 64, 245328 (2001), (preceding paper)], which combines the spherical eight-band effective-mass

  18. Investigation of energy band alignments and interfacial properties of rutile NMO2/TiO2 (NM = Ru, Rh, Os, and Ir) by first-principles calculations.

    Science.gov (United States)

    Yang, Chen; Zhao, Zong-Yan

    2017-11-08

    In the field of photocatalysis, constructing hetero-structures is an efficient strategy to improve quantum efficiency. However, a lattice mismatch often induces unfavorable interfacial states that can act as recombination centers for photo-generated electron-hole pairs. If the hetero-structure's components have the same crystal structure, this disadvantage can be easily avoided. Conversely, in the process of loading a noble metal co-catalyst onto the TiO 2 surface, a transition layer of noble metal oxides is often formed between the TiO 2 layer and the noble metal layer. In this article, interfacial properties of hetero-structures composed of a noble metal dioxide and TiO 2 with a rutile crystal structure have been systematically investigated using first-principles calculations. In particular, the Schottky barrier height, band bending, and energy band alignments are studied to provide evidence for practical applications. In all cases, no interfacial states exist in the forbidden band of TiO 2 , and the interfacial formation energy is very small. A strong internal electric field generated by interfacial electron transfer leads to an efficient separation of photo-generated carriers and band bending. Because of the differences in the atomic properties of the components, RuO 2 /TiO 2 and OsO 2 /TiO 2 hetero-structures demonstrate band dividing, while RhO 2 /TiO 2 and IrO 2 /TiO 2 hetero-structures have a pseudo-gap near the Fermi energy level. Furthermore, NMO 2 /TiO 2 hetero-structures show upward band bending. Conversely, RuO 2 /TiO 2 and OsO 2 /TiO 2 hetero-structures present a relatively strong infrared light absorption, while RhO 2 /TiO 2 and IrO 2 /TiO 2 hetero-structures show an obvious absorption edge in the visible light region. Overall, considering all aspects of their properties, RuO 2 /TiO 2 and OsO 2 /TiO 2 hetero-structures are more suitable than others for improving the photocatalytic performance of TiO 2 . These findings will provide useful information

  19. Exchange interaction in the heavy rare-earth metals calculated from energy bands

    International Nuclear Information System (INIS)

    Lindgard, P.A.; Liu, S.H.

    1973-01-01

    The exchange interaction in the ordered phases was calculated and found to be significantly influenced by the magnetic perturbation of the conduction electron states. The exchange interaction is intrinsically temperature dependent and is anisotropic. The effect explains how it is possible to have a spiral phase of Tb, although spin wave measurements show no maximum in J/sub q/ for q not equal to 0. The energy difference between the ferromagnetic and spiral phases is of correct order of magnitude to be counterbalanced by the magnetoelastic energy. The wave vector dependent matrix element is found to be similar for Gd, Tb, Dy, and Er with a narrow central conduction electron contribution and a flat region. (U.S.)

  20. Impact of Antibody Bioconjugation on Emission and Energy Band Profile of CdSeTe/ZnS Quantum Dots

    Science.gov (United States)

    Torchynska, T. V.; Gomez, J. A. Jaramillo; Polupan, G.; Macotela, L. G. Vega

    2018-03-01

    The variation of the photoluminescence (PL) and Raman scattering spectra of CdSeTe/ZnS quantum dots (QDs) on conjugation to an antibody has been investigated. Two types of CdSeTe/ZnS QD with different emission wavelength (705 nm and 800 nm) were studied comparatively before and after conjugation to anti-pseudorabies virus antibody (AB). Nonconjugated QDs were characterized by Gaussian-type PL bands. PL shifts to higher energy and asymmetric shape of PL bands was detected in PL spectra of bioconjugated QDs. The surface-enhanced Raman scattering effect was exhibited by the bioconjugated CdSeTe/ZnS QDs, indicating that the excitation light used in the Raman study generated electric dipoles in the AB molecules. The optical bandgap of the CdSeTe core was calculated numerically as a function of its radius based on an effective mass approximation model. The energy band diagrams for non- and bioconjugated CdSeTe/ZnS QDs were obtained, revealing a type II quantum well in the CdSeTe core. The calculations show that AB dipoles, excited in the bioconjugated QDs, stimulate a change in the energy band diagram of the QDs that alters the PL spectrum. These results could be useful for improving the sensitivity of QD biosensors.

  1. Energy band structure and electrical properties of Ga-oxide/GaN interface formed by remote oxygen plasma

    Science.gov (United States)

    Yamamoto, Taishi; Taoka, Noriyuki; Ohta, Akio; Truyen, Nguyen Xuan; Yamada, Hisashi; Takahashi, Tokio; Ikeda, Mitsuhisa; Makihara, Katsunori; Nakatsuka, Osamu; Shimizu, Mitsuaki; Miyazaki, Seiichi

    2018-06-01

    The energy band structure of a Ga-oxide/GaN structure formed by remote oxygen plasma exposure and the electrical interface properties of the GaN metal–oxide–semiconductor (MOS) capacitors with the SiO2/Ga-oxide/GaN structures with postdeposition annealing (PDA) at various temperatures have been investigated. Reflection high-energy electron diffraction and X-ray photoelectron spectroscopy clarified that the formed Ga-oxide layer is neither a single nor polycrystalline phase with high crystallinity. We found that the energy band offsets at the conduction band minimum and at the valence band maximum between the Ga-oxide layer and the GaN surface were 0.4 and 1.2 ± 0.2 eV, respectively. Furthermore, capacitance–voltage (C–V) characteristics revealed that the interface trap density (D it) is lower than the evaluation limit of Terman method without depending on the PDA temperatures, and that the SiO2/Ga-oxide stack can work as a protection layer to maintain the low D it, avoiding the significant decomposition of GaN at the high PDA temperature of 800 °C.

  2. Sustainable Energy Portfolios for Small Island States

    Directory of Open Access Journals (Sweden)

    Sándor Szabó

    2015-09-01

    Full Text Available The study presents a cost effective electricity generation portfolio for six island states for a 20-year period (2015–2035. The underlying concept investigates whether adding sizeable power capacities of renewable energy sources (RES options could decrease the overall costs and contribute to a more sustainable, indigenous electricity generation at the same time. Often, island states rely on fossil fuels which, apart from dependence on foreign resources, also includes an additional, significant transport cost. This is an extra motive to study the extent in which island states represent primary locations for RES technologies. For the aims of the present study an optimization model has been developed and following numerous runs the obtained results show that installing PV and battery capacities can delay-reduce the huge investments in fossil options in early periods. Thus, investment on RES can have a positive, long-term effect on the overall energy mix. This prompt development can happen without adding new subsidies but there is a need to address the existing socio-economic barriers with intelligent design of financing and economic instruments and capacity building as discussed in the conclusions.

  3. Calcium doped MAPbI3 with better energy state alignment in perovskite solar cells

    Science.gov (United States)

    Lu, Chaojie; Zhang, Jing; Hou, Dagang; Gan, Xinlei; Sun, Hongrui; Zeng, Zhaobing; Chen, Renjie; Tian, Hui; Xiong, Qi; Zhang, Ying; Li, Yuanyuan; Zhu, Yuejin

    2018-05-01

    The organic-inorganic perovskite material with better energy alignment in the solar cell device will have a profound impact on the solar cell performance. It is valuable to tune the energy states by element substitution and doping in perovskites. Here, we present that Ca2+ is incorporated into CH3NH3PbI3, which up-shifts the valence band maximum and the conduction band minimum, leading to a difference between the bandgap and the Fermi level in the device. Consequently, Ca2+ incorporation results in an enhancement of the photovoltage and photocurrent, achieving a summit efficiency of 18.3% under standard 1 sun (AM 1.5). This work reveals the doped perovskite to improve the solar cell performance by tuning the energy state.

  4. Anisotropic energy-gaps of iron-based superconductivity from intra-band quasiparticle interference in LiFeAs

    Energy Technology Data Exchange (ETDEWEB)

    Rost, A.W. [LASSP, Department of Physics, Cornell, Ithaca, NY 14853 (United States); SUPA, School of Physics and Astronomy, Univ. of St Andrews, St Andrews, Fife KY16 9SS (United Kingdom); Allan, M.P. [LASSP, Department of Physics, Cornell, Ithaca, NY 14853 (United States); SUPA, School of Physics and Astronomy, Univ. of St Andrews, St Andrews, Fife KY16 9SS (United Kingdom); CMPMS Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Mackenzie, A.P. [SUPA, School of Physics and Astronomy, Univ. of St Andrews, St Andrews, Fife KY16 9SS (United Kingdom); Xie, Y. [CMPMS Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Davis, J.C. [LASSP, Department of Physics, Cornell, Ithaca, NY 14853 (United States); SUPA, School of Physics and Astronomy, Univ. of St Andrews, St Andrews, Fife KY16 9SS (United Kingdom); CMPMS Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Kavli Institute at Cornell for Nanoscale Science, Cornell, Ithaca, NY 14853 (United States); Kihou, K.; Lee, C.H.; Iyo, A.; Eisaki, H. [AIST, Tsukuba, Ibaraki 305-8568 (Japan); Chuang, T.M. [LASSP, Department of Physics, Cornell, Ithaca, NY 14853 (United States); CMPMS Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Inst. of Physics, Academica Sinica, Nankang, Taipei 11529, Taiwan (China)

    2012-07-01

    Cooper pairing in the Fe-based superconductors is thought to occur due to the projection of the antiferromagnetic interactions between iron atoms onto the complex momentum-space electronic structure. A key consequence is that distinct anisotropic energy gaps {Delta}{sub i}(k) with specific relative orientations should occur on the different electronic bands i. To determine this previously unresolved gap structure high-precision spectroscopy is required. Here we introduce the STM technique of intra-band Bogolyubov quasiparticle scattering interference (QPI) to iron-based superconductor studies, focusing on LiFeAs. We identify the QPI signatures of three hole-like dispersions and, by introducing a new QPI technique, determine the magnitude and relative orientations of corresponding anisotropic {Delta}{sub i}(k). Intra-band Bogolyubov QPI therefore yields the spectroscopic information required to identify the mechanism of superconductivity in Fe-based superconductors.

  5. Role of band states and trap states in the electrical properties of organic semiconductors: Hopping versus mobility edge model

    KAUST Repository

    Mehraeen, Shafigh

    2013-05-01

    We compare the merits of a hopping model and a mobility edge model in the description of the effect of charge-carrier concentration on the electrical conductivity, carrier mobility, and Fermi energy of organic semiconductors. We consider the case of a composite electronic density of states (DOS) that consists of a superposition of a Gaussian DOS and an exponential DOS. Using kinetic Monte Carlo simulations, we apply the two models in order to interpret the recent experimental data reported for n-doped C60 films. While both models are capable of reproducing the experimental data very well and yield qualitatively similar characteristic parameters for the density of states, some discrepancies are found at the quantitative level. © 2013 American Physical Society.

  6. W-band Solid State Power Amplifier for Remote Sensing Radars, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — High power, compact, reliable and affordable power amplifiers operating in the W-band (94 GHz region) are critical to realizing transmitters for many NASA missions...

  7. W-Band Solid State Power Amplifier for Remote Sensing Radars, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — High power, compact, reliable and affordable power amplifiers operating in the W-band (94 GHz region) are critical to realizing transmitters for many NASA missions...

  8. Electric-dipole effect of defects on the energy band alignment of rutile and anatase TiO₂.

    Science.gov (United States)

    Zhang, Daoyu; Yang, Minnan; Dong, Shuai

    2015-11-21

    Titanium dioxide materials have been studied intensively and extensively for photocatalytic applications. A long-standing open question is the energy band alignment of rutile and anatase TiO2 phases, which can affect the photocatalytic process in the composite system. There are basically two contradictory viewpoints about the alignment of these two TiO2 phases supported by the respective experiments: (1) straddling type and (2) staggered type. In this work, our DFT plus U calculations show that the perfect rutile(110) and anatase(101) surfaces have the straddling type band alignment, whereas the surfaces with defects can turn the band alignment into the staggered type. The electric dipoles induced by defects are responsible for the reversal of band alignment. Thus the defects introduced during the preparation and post-treatment processes of materials are probably the answer to the above open question regarding the band alignment, which can be considered in real practice to tune the photocatalytic activity of materials.

  9. On minimal energy Hartree-Fock states for the 2DEG at fractional fillings

    International Nuclear Information System (INIS)

    Cabo Montes Oca, A. de.

    1995-08-01

    Approximate minimal energy solutions of the previously discussed general class of Hartree-Fock (HF) states of the 2DEG at 1/3 and 2/3 filling factors are determined. Their selfenergy spectrum is evaluated. Wannier states associated to the filled Bloch states are introduced in a lattice having three flux quanta per cell. They allow to rewrite approximately the ν = 1/3 HF Hamiltonian as sum of three independent tight-binding model Hamiltonians, one describing the dynamics in the band of occupied states and the other ones in the tow bands of excited states. The magnitude of the hopping integral indicates the enhanced role which should have the correlation energy in the present situation with respect to the case of the Yoshioka and Lee second order energy calculation for the lowest energy HF state. Finally, the discussion also suggests the Wannier function, which spreads an electron into a three quanta area, as a physical model for the composite fermion mean field one particle state. (author). 11 refs, 5 figs

  10. Design, realization and test of C-band accelerating structures for the SPARC-LAB linac energy upgrade

    International Nuclear Information System (INIS)

    Alesini, D.; Bellaveglia, M.; Biagini, M.E.; Boni, R.; Brönnimann, M.; Cardelli, F.; Chimenti, P.; Clementi, R.; Di Pirro, G.; Di Raddo, R.; Ferrario, M.; Ficcadenti, L.; Gallo, A.; Kalt, R.; Lollo, V.; Palumbo, L.; Piersanti, L.; Schilcher, T.

    2016-01-01

    The energy upgrade of the SPARC-LAB photo-injector at LNF-INFN (Frascati, Italy) has been originally conceived replacing one low gradient (13 MV/m) 3 m long SLAC type S-band traveling wave (TW) section with two 1.4 m long C-band accelerating sections. Due to the higher gradients reached by such structures, a higher energy beam can be obtained within the same accelerator footprint length. The use of C-band structures for electron acceleration has been adopted in a few FEL linacs in the world, among others, the Japanese Free Electron Laser at SPring-8 and the SwissFEL at Paul Scherrer Institute (PSI). The C-band sections are traveling wave, constant impedance structures with symmetric input and output axial couplers. Their design has been optimized for the operation with a SLED RF pulse compressor. In this paper we briefly review their design criteria and we focus on the construction, tuning, low and high-power RF tests. We also illustrate the design and realization of the dedicated low level RF system that has been done in collaboration with PSI in the framework of the EU TIARA project. Preliminary experimental results appear to confirm the operation of such structures with accelerating gradients larger than 35 MV/m.

  11. Design, realization and test of C-band accelerating structures for the SPARC-LAB linac energy upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Alesini, D.; Bellaveglia, M.; Biagini, M.E.; Boni, R. [INFN Laboratori Nazionali di Frascati, Via Enrico Fermi 40, 00044, Frascati (Italy); Brönnimann, M. [Paul Scherrer Institut, 5232 Villigen (Switzerland); Cardelli, F. [INFN Sezione di Roma, P.le Aldo Moro 2, 00185, Roma (Italy); Università di Roma “La Sapienza”, P.le Aldo Moro 2, 00185, Roma (Italy); Chimenti, P.; Clementi, R.; Di Pirro, G.; Di Raddo, R.; Ferrario, M. [INFN Laboratori Nazionali di Frascati, Via Enrico Fermi 40, 00044, Frascati (Italy); Ficcadenti, L. [INFN Sezione di Roma, P.le Aldo Moro 2, 00185, Roma (Italy); Università di Roma “La Sapienza”, P.le Aldo Moro 2, 00185, Roma (Italy); Gallo, A. [INFN Laboratori Nazionali di Frascati, Via Enrico Fermi 40, 00044, Frascati (Italy); Kalt, R. [Paul Scherrer Institut, 5232 Villigen (Switzerland); Lollo, V. [INFN Laboratori Nazionali di Frascati, Via Enrico Fermi 40, 00044, Frascati (Italy); Palumbo, L. [INFN Sezione di Roma, P.le Aldo Moro 2, 00185, Roma (Italy); Università di Roma “La Sapienza”, P.le Aldo Moro 2, 00185, Roma (Italy); Piersanti, L., E-mail: luca.piersanti@lnf.infn.it [INFN Sezione di Roma, P.le Aldo Moro 2, 00185, Roma (Italy); Università di Roma “La Sapienza”, P.le Aldo Moro 2, 00185, Roma (Italy); Schilcher, T. [Paul Scherrer Institut, 5232 Villigen (Switzerland)

    2016-11-21

    The energy upgrade of the SPARC-LAB photo-injector at LNF-INFN (Frascati, Italy) has been originally conceived replacing one low gradient (13 MV/m) 3 m long SLAC type S-band traveling wave (TW) section with two 1.4 m long C-band accelerating sections. Due to the higher gradients reached by such structures, a higher energy beam can be obtained within the same accelerator footprint length. The use of C-band structures for electron acceleration has been adopted in a few FEL linacs in the world, among others, the Japanese Free Electron Laser at SPring-8 and the SwissFEL at Paul Scherrer Institute (PSI). The C-band sections are traveling wave, constant impedance structures with symmetric input and output axial couplers. Their design has been optimized for the operation with a SLED RF pulse compressor. In this paper we briefly review their design criteria and we focus on the construction, tuning, low and high-power RF tests. We also illustrate the design and realization of the dedicated low level RF system that has been done in collaboration with PSI in the framework of the EU TIARA project. Preliminary experimental results appear to confirm the operation of such structures with accelerating gradients larger than 35 MV/m.

  12. Energy level broadening effect on the equation of state of hot dense Al and Au plasma

    International Nuclear Information System (INIS)

    Hou Yong; Jin Fengtao; Yuan Jianmin

    2007-01-01

    In the hot dense matter regime, the isothermal equation of state (EOS) of Al and Au is calculated using an average-atom (AA) model in which the broadening of energy levels of atoms and ions are accounted for by using with a Gaussian distribution of the density of states. The distribution of bound electrons in the energy bands is determined by the continuum Fermi-Dirac distribution. With a self-consistent field average atoms scheme, it is shown that the energy-level broadening has a significant effect on the isothermal equation of state (EOS) of Al and Au in the hot dense matter regime. The jumps in the equation of state (EOS) induced by pressure ionization of the one-electron orbital with the increase in density, which often occur in the normal average-atom model and have been avoided by generally introducing the pseudo-shape resonance states, disappear naturally

  13. Mass Enhancement of Nearly Trivalent Compound EuCo2Si2: Studied by the de Haas-van Alphen Experiments and Energy Band Calculations

    International Nuclear Information System (INIS)

    Ōnuki, Yoshichika; Hedo, Masato; Nakama, Takao; Nakamura, Ai; Aoki, Dai; Boukahil, Mounir; Haga, Yoshinori; Takeuchi, Tetsuya; Harima, Hisatomo

    2015-01-01

    We succeeded in growing single crystals of EuCo 2 Si 2 by the Bridgman method, and carried out the de Haas-van Alphen (dHvA) experiments. EuCo 2 Si 2 was previously studied from a viewpoint of the trivalent electronic state on the basis of the magnetic susceptibility and X-ray absorption experiments, whereas most of the other Eu compounds order magnetically, with the divalent electronic state. The detected dHvA branches in the present experiments are found to be explained by the results of the full potential linearized augmented plane wave energy band calculations on the basis of a local density approximation (LDA) for YCo 2 Si 2 (LDA) and EuCo 2 Si 2 (LDA + U), revealing the trivalent electronic state. The detected cyclotron effective masses are moderately large, ranging from 1.2 to 2.9 m 0

  14. Light-Induced Type-II Band Inversion and Quantum Anomalous Hall State in Monolayer FeSe

    Science.gov (United States)

    Wang, Z. F.; Liu, Zhao; Yang, Jinlong; Liu, Feng

    2018-04-01

    Coupling a quantum anomalous Hall (QAH) state with a superconducting state offers an attractive approach to detect the signature alluding to a topological superconducting state [Q. L. He et al., Science 357, 294 (2017), 10.1126/science.aag2792], but its explanation could be clouded by disorder effects in magnetic doped QAH materials. On the other hand, an antiferromagnetic (AFM) quantum spin Hall (QSH) state is identified in the well-known high-temperature 2D superconductor of monolayer FeSe [Z. F. Wang et al., Nat. Mater. 15, 968 (2016), 10.1038/nmat4686]. Here, we report a light-induced type-II band inversion (BI) and a QSH-to-QAH phase transition in the monolayer FeSe. Depending on the handedness of light, a spin-tunable QAH state with a high Chern number of ±2 is realized. In contrast to the conventional type-I BI resulting from intrinsic spin-orbital coupling (SOC), which inverts the band an odd number of times and respects time reversal symmetry, the type-II BI results from a light-induced handedness-dependent effective SOC, which inverts the band an even number of times and does not respect time reversal symmetry. The interplay between these two SOC terms makes the spin-up and -down bands of an AFM QSH state respond oppositely to a circularly polarized light, leading to the type-II BI and an exotic topological phase transition. Our finding affords an exciting opportunity to detect Majorana fermions in one single material without magnetic doping.

  15. Energy intensity ratios as net energy measures of United States energy production and expenditures

    International Nuclear Information System (INIS)

    King, C W

    2010-01-01

    In this letter I compare two measures of energy quality, energy return on energy invested (EROI) and energy intensity ratio (EIR) for the fossil fuel consumption and production of the United States. All other characteristics being equal, a fuel or energy system with a higher EROI or EIR is of better quality because more energy is provided to society. I define and calculate the EIR for oil, natural gas, coal, and electricity as measures of the energy intensity (units of energy divided by money) of the energy resource relative to the energy intensity of the overall economy. EIR measures based upon various unit prices for energy (e.g. $/Btu of a barrel of oil) as well as total expenditures on energy supplies (e.g. total dollars spent on petroleum) indicate net energy at different points in the supply chain of the overall energy system. The results indicate that EIR is an easily calculated and effective proxy for EROI for US oil, gas, coal, and electricity. The EIR correlates well with previous EROI calculations, but adds additional information on energy resource quality within the supply chain. Furthermore, the EIR and EROI of oil and gas as well as coal were all in decline for two time periods within the last 40 years, and both time periods preceded economic recessions.

  16. A Method against Interrupted-Sampling Repeater Jamming Based on Energy Function Detection and Band-Pass Filtering

    Directory of Open Access Journals (Sweden)

    Hui Yuan

    2017-01-01

    Full Text Available Interrupted-sampling repeater jamming (ISRJ is a new kind of coherent jamming to the large time-bandwidth linear frequency modulation (LFM signal. Many jamming modes, such as lifelike multiple false targets and dense false targets, can be made through setting up different parameters. According to the “storage-repeater-storage-repeater” characteristics of the ISRJ and the differences in the time-frequency-energy domain between the ISRJ signal and the target echo signal, one new method based on the energy function detection and band-pass filtering is proposed to suppress the ISRJ. The methods mainly consist of two parts: extracting the signal segments without ISRJ and constructing band-pass filtering function with low sidelobe. The simulation results show that the method is effective in the ISRJ with different parameters.

  17. Dipole Bands in 196Hg

    International Nuclear Information System (INIS)

    Lawrie, J. J.; Lawrie, E. A.; Newman, R. T.; Sharpey-Schafer, J. F.; Smit, F. D.; Msezane, B.; Benatar, M.; Mabala, G. K.; Mutshena, K. P.; Federke, M.; Mullins, S. M.; Ncapayi, N. J.; Vymers, P.

    2011-01-01

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

  18. United States energy policy, 1980--1988

    International Nuclear Information System (INIS)

    1988-10-01

    This report reviews the nation's energy policy over the past several years. It looks at how domestic oil, energy efficiency, natural gas, nuclear energy, and renewable energy resources can help maintain and enhance our energy security. It surveys advances in energy technologies from enhanced oil recovery to new clean coal processes. It also describes the federal research programs in the basic energy sciences and it outlines the environmental issues that may profoundly affect our future energy choices

  19. Strongly correlated quasi-one-dimensional bands: Ground states, optical absorption, and phonons

    International Nuclear Information System (INIS)

    Campbell, D.K.; Gammel, J.T.; Loh, E.Y. Jr.

    1989-01-01

    Using the Lanczos method for exact diagonalization on systems up to 14 sites, combined with a novel ''phase randomization'' technique for extracting more information from these small systems, we investigate several aspects of the one-dimensional Peierls-Hubbard Hamiltonian, in the context of trans-polyacetylene: the dependence of the ground state dimerization on the strength of the electron-electron interactions, including the effects of ''off-diagonal'' Coulomb terms generally ignored in the Hubbard model; the phonon vibrational frequencies and dispersion relations, and the optical absorption properties, including the spectrum of absorptions as a function of photon energy. These three different observables provide considerable insight into the effects of electron-electron interactions on the properties of real materials and thus into the nature of strongly correlated electron systems. 29 refs., 11 figs

  20. Localization length and fractal dimension of band centre states for 1-d off-diagonal disordered systems

    International Nuclear Information System (INIS)

    Roman, E.; Wiecko, C.

    1985-08-01

    We study and characterize the eigenstates near the centre of the band of a 1-d tight binding model with off-diagonal disorder Wsub(T). We find a new exponent for the localization length lambda on an energy-dependent range of disorder Wsub(T). We correlate this feature with a change of structure of the wave-function displayed by the behaviour of its fractal dimensionality. (author)

  1. Symmetry energy II: Isobaric analog states

    Science.gov (United States)

    Danielewicz, Pawel; Lee, Jenny

    2014-02-01

    Using excitation energies to isobaric analog states (IAS) and charge invariance, we extract nuclear symmetry coefficients, representing a mass formula, on a nucleus-by-nucleus basis. Consistently with charge invariance, the coefficients vary weakly across an isobaric chain. However, they change strongly with nuclear mass and range from aa˜10 MeV at mass A˜10 to aa˜22 MeV at A˜240. Variation with mass can be understood in terms of dependence of nuclear symmetry energy on density and the rise in importance of low densities within nuclear surface in smaller systems. At A≳30, the dependence of coefficients on mass can be well described in terms of a macroscopic volume-surface competition formula with aaV≃33.2 MeV and aaS≃10.7 MeV. Our further investigation shows, though, that the fitted surface symmetry coefficient likely significantly underestimates that for the limit of half-infinite matter. Following the considerations of a Hohenberg-Kohn functional for nuclear systems, we determine how to find in practice the symmetry coefficient using neutron and proton densities, even when those densities are simultaneously affected by significant symmetry-energy and Coulomb effects. These results facilitate extracting the symmetry coefficients from Skyrme-Hartree-Fock (SHF) calculations, that we carry out using a variety of Skyrme parametrizations in the literature. For the parametrizations, we catalog novel short-wavelength instabilities. In our further analysis, we retain only those parametrizations which yield systems that are adequately stable both in the long- and short-wavelength limits. In comparing the SHF and IAS results for the symmetry coefficients, we arrive at narrow (±2.4 MeV) constraints on the symmetry-energy values S(ρ) at 0.04≲ρ≲0.13 fm. Towards normal density the constraints significantly widen, but the normal value of energy aaV and the slope parameter L are found to be strongly correlated. To narrow the constraints, we reach for the

  2. The state of energy resources and role of nuclear energy

    International Nuclear Information System (INIS)

    Rosen, M.; )

    1999-01-01

    The present and future global energy demand has been assessed. The nuclear energy contribution in world energy balance has been discussed taking into account economical, social and environmental circumstances

  3. Charge Energy Transport in Hopping Systems with Rapidly Decreasing Density of States

    Science.gov (United States)

    Mendels, Dan; Organic Electronics Group Technion Team

    2014-03-01

    An accurate description of the carrier hopping topology in the energy domain of hopping systems incorporating a rapidly decreasing density of states and the subsequent energetic position of these systems' so called effective conduction band is crucial for rationalizing and quantifying these systems' thermo-electric properties, doping related phenomena and carrier gradient effects such as the emergence of the General Einstein Relation under degenerate conditions. Additionally, as will be shown, the 'mobile' carriers propagating through the system can have excess energies reaching 0.3eV above the system quasi-Fermi energy. Hence, since these mobile carriers are most prone to reach systems interfaces and interact with oppositely charged carriers, their excess energy should be considered in determining the efficiencies of energy dependent processes such as carrier recombination and exciton dissociation. In light of the stated motivations, a comprehensive numerical and analytical study of the topology of hopping in the energetic density of such systems (i.e. the statistics regarding which energy values carriers visit most and in what manner) was implemented and the main statistical features of the hopping process that determine the position in energy of the system's effective conduction band were distilled. The obtained results also help shed light on yet to be elucidated discrepancies between predictions given by the widely employed transport energy concept and Monte Carlo simulations.

  4. Carrier-carrier relaxation kinetics in quantum well semiconductor structures with nonparabolic energy bands

    DEFF Research Database (Denmark)

    Dery, H.; Tromborg, Bjarne; Eisenstein, G.

    2003-01-01

    We describe carrier-carrier scattering dynamics in an inverted quantum well structure including the nonparabolic nature of the valance band. A solution of the semiconductor Bloch equations yields strong evidence to a large change in the temporal evolution of the carrier distributions compared to ...

  5. New Method for the Development of Plasmonic Metal-Semiconductor Interface Layer: Polymer Composites with Reduced Energy Band Gap

    Directory of Open Access Journals (Sweden)

    Shujahadeen B. Aziz

    2017-01-01

    Full Text Available Silver nanoparticles within a host polymer of chitosan were synthesized by using in situ method. Ultraviolet-visible spectroscopy was then carried out for the prepared chitosan : silver triflate (CS : AgTf samples, showing a surface plasmonic resonance (SPR peak at 420 nm. To prepare polymer composites with reduced energy band gap, different amounts of alumina nanoparticles were incorporated into the CS : AgTf solution. In the present work, the results showed that the reduced silver nanoparticles and their adsorption on wide band gap alumina (Al2O3 particles are an excellent approach for the preparation of polymer composites with small optical band gaps. The optical dielectric loss parameter has been used to determine the band gap experimentally. The physics behind the optical dielectric loss were interpreted from the viewpoint of quantum mechanics. From the quantum-mechanics viewpoint, optical dielectric loss was also found to be a complex equation and required lengthy numerical computation. From the TEM investigation, the adsorption of silver nanoparticles on alumina has been observed. The optical micrograph images showed white spots (silver specks with different sizes on the surface of the films. The second semicircle in impedance Cole-Cole plots was found and attributed to the silver particles.

  6. Analytical realization of finite-size scaling for Anderson localization. Does the band of critical states exist for d > 2?

    International Nuclear Information System (INIS)

    Suslov, I. M.

    2006-01-01

    An analytical realization is suggested for the finite-size scaling algorithm based on the consideration of auxiliary quasi-1D systems. Comparison of the obtained analytical results with the results of numerical calculations indicates that the Anderson transition point splits into the band of critical states. This conclusion is supported by direct numerical evidence (Edwards, Thouless, 1972; Last, Thouless, 1974; Schreiber, 1985). The possibility of restoring the conventional picture still exists but requires a radical reinterpretation of the raw numerical data

  7. Mixing of ground-state rotational and gamma and beta vibrational bands in the region A>=228

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, R; Sahota, H S [Punjabi Univ., Patiala (India). Dept. of Physics

    1983-06-21

    The mixing of beta, gamma and ground-state bands has been investigated through the experimental determination of mixing parameters Zsub(..gamma..) and Zsub(..beta gamma..). These Zsub(..gamma..) values have been compared with the theoretical calculations of this parameter from the solutions of time-dependent HFB equations on the adiabatic and nonadiabatic assumptions. The experimental values are in better agreement with the results obtained under the nonadiabatic assumption, valid for small deviations from the spherical symmetry.

  8. Cytotoxicity Comparison of the Nanoparticles Deposited on Latex Rubber Bands between the Original and Stretched State

    Directory of Open Access Journals (Sweden)

    Jung-Hwan Lee

    2014-01-01

    Full Text Available Understanding the biocompatibility of nanoparticles in dental materials is essential for their safe usage in the oral cavity. In this study, we investigated whether nanoparticles deposited on orthodontic latex rubber bands are involved in the induction of cytotoxicity. A method of stretching to three times (“3L” the length of the latex rubber bands was employed to detach the particles using the original length (“L” for comparison. The cytotoxicity tests were performed on extracts with mouse fibroblasts (L929 and human gingival fibroblasts (HGFs. Fourier transform infrared spectroscopy, ion chromatography, elemental analysis, and inductively coupled plasma mass spectrometry (ICP-MS were performed to detect the harmful components in the extracts from rubber bands. There was a significant decrease in the cell viability in the “L” samples compared with the “3L” samples (P<0.05 in the L929 and HGF cells. This was due to the Ni single crystal nanoparticles (~50nm from the inner surface of “L” samples that were detached in the “3L” samples as well as the Zn ion (~9 ppm detected in the extract. This study revealed that the Ni nanoparticles, as well as Zn ions, were involved in the induction of cytotoxicity from the latex rubber bands.

  9. Reconstructing the energy band electronic structure of pulsed laser deposited CZTS thin films intended for solar cell absorber applications

    Energy Technology Data Exchange (ETDEWEB)

    Pandiyan, Rajesh [Institut National de la Recherche Scientifique, Centre-Énergie, Matériaux et Télécommunications, 1650 Blvd. Lionel–Boulet, C.P. 1020, Varennes, QC J3X-1S2 (Canada); Oulad Elhmaidi, Zakaria [Institut National de la Recherche Scientifique, Centre-Énergie, Matériaux et Télécommunications, 1650 Blvd. Lionel–Boulet, C.P. 1020, Varennes, QC J3X-1S2 (Canada); University of Mohammed V, Faculty of Sciences, Materials Physics Laboratory, B.P. 1014 Rabat (Morocco); Sekkat, Zouheir [Optics & Photonics Center, Moroccan Foundation for Advanced Science, Innovation and Research, Rabat (Morocco); Abd-lefdil, Mohammed [University of Mohammed V, Faculty of Sciences, Materials Physics Laboratory, B.P. 1014 Rabat (Morocco); El Khakani, My Ali, E-mail: elkhakani@emt.inrs.ca [Institut National de la Recherche Scientifique, Centre-Énergie, Matériaux et Télécommunications, 1650 Blvd. Lionel–Boulet, C.P. 1020, Varennes, QC J3X-1S2 (Canada)

    2017-02-28

    Highlights: • High quality CZTS thin films grown by means of PLD technique without resorting to any post sulfurization process. • Effect of thermal annealing treatments (in the 200–500 °C range) on the structural, morphological and optoelectronic properties of PLD-CZTS films. • Experimental determination of key optoelectronic parameters (i.e.; E{sub g}, VBM, ϕ, I{sub p}, and χ) enabling the reconstruction of energy band electronic structure of the PLD-CZTS films. • Investigation on the energy band alignments of the heterojunction interface formed between CZTS and both CdS and ZnS buffer layer materials. - Abstract: We report here on the use of pulsed KrF-laser deposition (PLD) technique for the growth of high-quality Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films onto Si, and glass substrates without resorting to any post sulfurization process. The PLD-CZTS films were deposited at room temperature (RT) and then subjected to post annealing at different temperatures ranging from 200 to 500 °C in Argon atmosphere. The X-ray diffraction and Raman spectroscopy confirmed that the PLD films crystallize in the characteristic kesterite CZTS structure regardless of their annealing temperature (T{sub a}), but their crystallinity is much improved for T{sub a} ≥ 400 °C. The PLD-CZTS films were found to exhibit a relatively dense morphology with a surface roughness (RMS) that increases with T{sub a} (from ∼14 nm at RT to 70 nm at T{sub a} = 500 °C with a value around 40 nm for T{sub a} = 300–400 °C). The optical bandgap of the PLD-CZTS films, was derived from UV–vis transmission spectra analysis, and found to decrease from 1.73 eV for non-annealed films to ∼1.58 eV for those annealed at T{sub a} = 300 °C. These band gap values are very close to the optimum value needed for an ideal solar cell absorber. In order to achieve a complete reconstruction of the one-dimensional energy band structure of these PLD-CZTS absorbers, we have combined both XPS and UPS

  10. State of Oregon 4th biennial energy plan

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    State law directs the Oregon Department of Energy (ODOE) to prepare an energy plan every two years. This is the Fourth Biennial Energy Plan. The Plan is a policy blueprint for how to best meet Oregon's future energy needs. It identifies the key energy issues facing the state and sets forth policies and actions to achieve our energy goals of reliable, least-cost, and environmentally safe supply. This book presents: Oregon's demand and supply picture today. The progress Oregon has made toward energy efficiency. Oregon's energy demand and supply outlook for the next 20 years. Estimates of cost-effective conservation and other resources that could contribute to the state's energy supply. The major energy-related health, safety, and environmental issues facing the state. A strategy to reduce greenhouse gas emissions 20 percent from 1988 levels by 2005. A two-year Action Plant that spells out ODOE's recommended actions for achieving Oregon's energy goals

  11. Surface Resonance Bands on (001)W: Experimental Dispersion Relations

    DEFF Research Database (Denmark)

    Willis, R. F.; Feuerbacher, B.; Christensen, N. Egede

    1977-01-01

    A band of unbound surface states (resonances), located in an energy region above the vacuum threshold corresponding to an energy band gap in the electron states of the bulk crystal, has been observed by angle-resolved secondary-electron-emission spectroscopy. The experimental dispersion behavior...... is in agreement with the two-dimensional band structure of a clean (001)W surface recently proposed by Smith and Mittheiss....

  12. State-to-State Mode Specificity: Energy Sequestration and Flow Gated by Transition State.

    Science.gov (United States)

    Zhao, Bin; Sun, Zhigang; Guo, Hua

    2015-12-23

    Energy flow and sequestration at the state-to-state level are investigated for a prototypical four-atom reaction, H2 + OH → H + H2O, using a transition-state wave packet (TSWP) method. The product state distribution is found to depend strongly on the reactant vibrational excitation, indicating mode specificity at the state-to-state level. From a local-mode perspective, it is shown that the vibrational excitation of the H2O product derives from two different sources, one attributable to the energy flow along the reaction coordinate into the newly formed OH bond and the other due to the sequestration of the vibrational energy in the OH spectator moiety during the reaction. The analysis provided a unified interpretation of some seemingly contradicting experimental observations. It is further shown that the transfer of vibrational energy from the OH reactant to H2O product is gated by the transition state, accomplished coherently by multiple TSWPs with the corresponding OH vibrational excitation.

  13. States of low energy on Robertson-Walker spacetimes

    International Nuclear Information System (INIS)

    Olbermann, Heiner

    2007-01-01

    We construct a new class of physical states of the free Klein-Gordon field in Robertson-Walker spacetimes. This is done by minimizing the expectation value of smeared stress-energy. We get an explicit expression for the state depending on the smearing function. We call it a state of low energy. States of low energy are an improvement of the concept of adiabatic vacua on Robertson-Walker spacetimes. The latter are approximations of the former. It is shown that states of low energy are Hadamard states

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

    Directory of Open Access Journals (Sweden)

    Bi-Ru Wu

    2014-08-01

    Full Text Available 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.

  15. Optically Discriminating Carrier-Induced Quasiparticle Band Gap and Exciton Energy Renormalization in Monolayer MoS_{2}.

    Science.gov (United States)

    Yao, Kaiyuan; Yan, Aiming; Kahn, Salman; Suslu, Aslihan; Liang, Yufeng; Barnard, Edward S; Tongay, Sefaattin; Zettl, Alex; Borys, Nicholas J; Schuck, P James

    2017-08-25

    Optoelectronic excitations in monolayer MoS_{2} manifest from a hierarchy of electrically tunable, Coulombic free-carrier and excitonic many-body phenomena. Investigating the fundamental interactions underpinning these phenomena-critical to both many-body physics exploration and device applications-presents challenges, however, due to a complex balance of competing optoelectronic effects and interdependent properties. Here, optical detection of bound- and free-carrier photoexcitations is used to directly quantify carrier-induced changes of the quasiparticle band gap and exciton binding energies. The results explicitly disentangle the competing effects and highlight longstanding theoretical predictions of large carrier-induced band gap and exciton renormalization in two-dimensional semiconductors.

  16. Optically Discriminating Carrier-Induced Quasiparticle Band Gap and Exciton Energy Renormalization in Monolayer MoS2

    Science.gov (United States)

    Yao, Kaiyuan; Yan, Aiming; Kahn, Salman; Suslu, Aslihan; Liang, Yufeng; Barnard, Edward S.; Tongay, Sefaattin; Zettl, Alex; Borys, Nicholas J.; Schuck, P. James

    2017-08-01

    Optoelectronic excitations in monolayer MoS2 manifest from a hierarchy of electrically tunable, Coulombic free-carrier and excitonic many-body phenomena. Investigating the fundamental interactions underpinning these phenomena—critical to both many-body physics exploration and device applications—presents challenges, however, due to a complex balance of competing optoelectronic effects and interdependent properties. Here, optical detection of bound- and free-carrier photoexcitations is used to directly quantify carrier-induced changes of the quasiparticle band gap and exciton binding energies. The results explicitly disentangle the competing effects and highlight longstanding theoretical predictions of large carrier-induced band gap and exciton renormalization in two-dimensional semiconductors.

  17. United States Department of Energy: a history

    Energy Technology Data Exchange (ETDEWEB)

    Holl, J.M.

    1982-11-01

    This pamphlet traces the origins of the Department of Energy and outlines the history of the Department as reflected in the energy policies of Presidents Nixon, Ford, Carter, and Reagan. It attempts to place recent energy policy into historical perspective by describing the evolution of the federal Government's role in energy research, development, and regulation.

  18. Impurity Resonant States p-type Doping in Wide-Band-Gap Nitrides

    Science.gov (United States)

    Liu, Zhiqiang; Yi, Xiaoyan; Yu, Zhiguo; Yuan, Gongdong; Liu, Yang; Wang, Junxi; Li, Jinmin; Lu, Na; Ferguson, Ian; Zhang, Yong

    2016-01-01

    In this work, a new strategy for achieving efficient p-type doping in high bandgap nitride semiconductors to overcome the fundamental issue of high activation energy has been proposed and investigated theoretically, and demonstrated experimentally. Specifically, in an AlxGa1-xN/GaN superlattice structure, by modulation doping of Mg in the AlxGa1-xN barriers, high concentration of holes are generated throughout the material. A hole concentration as high as 1.1 × 1018 cm-3 has been achieved, which is about one order of magnitude higher than that typically achievable by direct doping GaN. Results from first-principle calculations indicate that the coupling and hybridization between Mg 2p impurity and the host N 2p orbitals are main reasons for the generation of resonant states in the GaN wells, which further results in the high hole concentration. We expect this approach to be equally applicable for other high bandgap materials where efficient p-type doing is difficult. Furthermore, a two-carrier-species Hall-effect model is proposed to delineate and discriminate the characteristics of the bulk and 2D hole, which usually coexist in superlattice-like doping systems. The model reported here can also be used to explain the abnormal freeze-in effect observed in many previous reports.

  19. Electronic energy states of HfSe/sub 2/ and NbSe/sub 2/ by low energy electron loss spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Ito, T; Iwami, M; Hiraki, A [Osaka Univ., Suita (Japan). Faculty of Engineering

    1981-06-01

    Low energy electron loss spectroscopy (ELS) study was performed on 1T-HfSe/sub 2/ (group IVB metal compound) and 2H-NbSe/sub 2/ (group VB metal compound) by using incident electron energies of 30-250 eV. From the loss data in the second derivative form, maxima in density-of-states in the conduction band of the compounds were deduced through the information on the filled core states by X-ray photoelectron spectroscopy. The conduction band of the transition-metal dichalcogenides could be divided into two parts. The results are discussed in relation to the previous work on WS/sub 2/ (group VIB metal compound), and also to proposals based on band calculations and experimental studies on the transition-metal dichalcogenides with constituent metals of group IVB, VB and VIB.

  20. Lac du Flambeau Band of Lake Superior Chippewa Indians Strategic Energy Plan

    Energy Technology Data Exchange (ETDEWEB)

    Bryan Hoover

    2009-11-16

    This plan discusses the current energy use on the Lac du Flambeau Reservation, the current status of the Tribe's energy program, as well as the issues and concerns with energy on the reservation. This plan also identifies and outlines energy opportunities, goals, and objectives for the Tribe to accomplish. The overall goal of this plan is to address the energy situation of the reservation in a holistic manner for the maximum benefit to the Tribe. This plan is an evolving document that will be re-evaluated as the Tribe's energy situation changes.

  1. Forecast of the energy final consumption for Minas Gerais State

    International Nuclear Information System (INIS)

    Almeida, P.E.F. de; Bechtlufft, P.C.T.; Araujo, M.E.A.; Vasconcelos, E.C.; Las Casas, H.B. de; Monteiro, M.A.G.

    1990-01-01

    This paper is included among the activities of the Energy Planning of Minas Gerais State and presents a forecast of the energy final consumption for the State up to year 2010. Two Scenarios are presented involving brazilian economy's evolution, the State's demography and its sectors: residential, services, transportation, agriculture and cattle-breeding and industry. Finally, it shows two forecast on energy final consumption for Minas Gerais State. (author)

  2. Density functional theory calculations for the band gap and formation energy of Pr4-xCaxSi12O3+xN18-x; a highly disordered compound with low symmetry and a large cell size.

    Science.gov (United States)

    Hong, Sung Un; Singh, Satendra Pal; Pyo, Myoungho; Park, Woon Bae; Sohn, Kee-Sun

    2017-06-28

    A novel oxynitride compound, Pr 4-x Ca x Si 12 O 3+x N 18-x , synthesized using a solid-state route has been characterized as a monoclinic structure in the C2 space group using Rietveld refinement on synchrotron powder X-ray diffraction data. The crystal structure of this compound was disordered due to the random distribution of Ca/Pr and N/O ions at various Wyckoff sites. A pragmatic approach for an ab initio calculation based on density function theory (DFT) for this disordered compound has been implemented to calculate an acceptable value of the band gap and formation energy. In general, for the DFT calculation of a disordered compound, a sufficiently large super cell and infinite variety of ensemble configurations is adopted to simulate the random distribution of ions; however, such an approach is time consuming and cost ineffective. Even a single unit cell model gave rise to 43 008 independent configurations as an input model for the DFT calculations. Since it was nearly impossible to calculate the formation energy and the band gap energy for all 43 008 configurations, an elitist non-dominated sorting genetic algorithm (NSGA-II) was employed to find the plausible configurations. In the NSGA-II, all 43 008 configurations were mathematically treated as genomes and the calculated band gap and the formation energy as the objective (fitness) function. Generalized gradient approximation (GGA) was first employed in the preliminary screening using NSGA-II, and thereafter a hybrid functional calculation (HSE06) was executed only for the most plausible GGA-relaxed configurations with lower formation and higher band gap energies. The final band gap energy (3.62 eV) obtained after averaging over the selected configurations, resembles closely the experimental band gap value (4.11 eV).

  3. Assistance to States on Policies Related to Wind Energy Issues

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Matthew, H; Decesaro, Jennifer; DOE Project Officer - Keith Bennett

    2005-07-15

    This final report summarizes work carried out under agreement with the US Department of Energy, related to wind energy policy issues. This project has involved a combination of outreach and publications on wind energy, with a specific focus on educating state-level policymakers. Education of state policymakers is vitally important because state policy (in the form of incentives or regulation) is a crucial part of the success of wind energy. State policymakers wield a significant influence over all of these policies. They are also in need of high quality, non-biased educational resources which this project provided. This project provided outreach to legislatures, in the form of meetings designed specifically for state legislators and legislative staff, responses to information requests on wind energy, and publications. The publications addressed: renewable energy portfolio standards, wind energy transmission, wind energy siting, case studies of wind energy policy, avian issues, economic development, and other related issues. These publications were distributed to legislative energy committee members, and chairs, legislative staff, legislative libraries, and other related state officials. The effect of this effort has been to provide an extensive resource of information about wind information for state policymakers in a form that is useful to them. This non-partisan information has been used as state policymakers attempt to develop their own policy proposals related to wind energy in the states.

  4. Accuracy of Stated Energy Contents of Restaurant Foods

    Science.gov (United States)

    Urban, Lorien E.; McCrory, Megan A.; Dallal, Gerard E.; Das, Sai Krupa; Saltzman, Edward; Weber, Judith L.; Roberts, Susan B.

    2015-01-01

    Context National recommendations for the prevention and treatment of obesity emphasize reducing energy intake. Foods purchased in restaurants provide approximately 35% of the daily energy intake in US individuals but the accuracy of the energy contents listed for these foods is unknown. Objective To examine the accuracy of stated energy contents of foods purchased in restaurants. Design and Setting A validated bomb calorimetry technique was used to measure dietary energy in food from 42 restaurants, comprising 269 total food items and 242 unique foods. The restaurants and foods were randomly selected from quick-serve and sit-down restaurants in Massachusetts, Arkansas, and Indiana between January and June 2010. Main Outcome Measure The difference between restaurant-stated and laboratory-measured energy contents, which were corrected for standard metabolizable energy conversion factors. Results The absolute stated energy contents were not significantly different from the absolute measured energy contents overall (difference of 10 kcal/portion; 95% confidence interval [CI], −15 to 34 kcal/portion; P=.52); however, the stated energy contents of individual foods were variable relative to the measured energy contents. Of the 269 food items, 50 (19%) contained measured energy contents of at least 100 kcal/portion more than the stated energy contents. Of the 10% of foods with the highest excess energy in the initial sampling, 13 of 17 were available for a second sampling. In the first analysis, these foods contained average measured energy contents of 289 kcal/portion (95% CI, 186 to 392 kcal/portion) more than the stated energy contents; in the second analysis, these foods contained average measured energy contents of 258 kcal/portion (95% CI, 154 to 361 kcal/portion) more than the stated energy contents (Prestaurant foods were accurate overall. However, there was substantial inaccuracy for some individual foods, with understated energy contents for those with lower

  5. 77 FR 14509 - State Energy Program and Energy Efficiency and Conservation Block Grant (EECBG) Program; Request...

    Science.gov (United States)

    2012-03-12

    ... DEPARTMENT OF ENERGY [Docket No. EESEP0216] State Energy Program and Energy Efficiency and Conservation Block Grant (EECBG) Program; Request for Information AGENCY: Office of Energy Efficiency and... (SEP) and Energy Efficiency and Conservation Block Grant (EECBG) program, in support of energy...

  6. Binding energies of two deltas bound states

    International Nuclear Information System (INIS)

    Sato, Hiroshi; Saito, Koichi.

    1982-06-01

    Bound states of the two-deltas system are investigated by employing the realistic one boson exchange potential. It is found that there exist many bound states in each isospin channel and also found that the tensor interaction plays important role in producing these bound states. Relationship between these bound states and dibaryon resonances is discussed. (J.P.N.)

  7. Organic semiconductor density of states controls the energy level alignment at electrode interfaces

    Science.gov (United States)

    Oehzelt, Martin; Koch, Norbert; Heimel, Georg

    2014-01-01

    Minimizing charge carrier injection barriers and extraction losses at interfaces between organic semiconductors and metallic electrodes is critical for optimizing the performance of organic (opto-) electronic devices. Here, we implement a detailed electrostatic model, capable of reproducing the alignment between the electrode Fermi energy and the transport states in the organic semiconductor both qualitatively and quantitatively. Covering the full phenomenological range of interfacial energy level alignment regimes within a single, consistent framework and continuously connecting the limiting cases described by previously proposed models allows us to resolve conflicting views in the literature. Our results highlight the density of states in the organic semiconductor as a key factor. Its shape and, in particular, the energy distribution of electronic states tailing into the fundamental gap is found to determine both the minimum value of practically achievable injection barriers as well as their spatial profile, ranging from abrupt interface dipoles to extended band-bending regions. PMID:24938867

  8. Energy band and transport properties in magnetic aperiodic graphene superlattices of Thue-Morse sequence

    Science.gov (United States)

    Yin, Yiheng; Niu, Yanxiong; Zhang, Huiyun; Zhang, Yuping; Liu, Haiyue

    2016-02-01

    Utilizing the transfer matrix method, we develop the electronic band structure and transport properties in Thue-Morse aperiodic graphene superlattices with magnetic barriers. It is found that the normal transmission is blocked and the position of the Dirac point can be shifted along the wavevector axis by changing the height and width ratio of magnetic barriers, which is intrinsic different from electronic field modulated superlattices. In addition, the angular threshold property of the transmission spectra and the oscillatory property of the conductance have been studied.

  9. Energy band alignment at ferroelectric/electrode interface determined by photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Chen Feng; Wu Wen-Bin; Li Shun-Yi; Klein Andreas

    2014-01-01

    The most important interface-related quantities determined by band alignment are the barrier heights for charge transport, given by the Fermi level position at the interface. Taking Pb(Zr,Ti)O 3 (PZT) as a typical ferroelectric material and applying X-ray photoelectron spectroscopy (XPS), we briefly review the interface formation and barrier heights at the interfaces between PZT and electrodes made of various metals or conductive oxides. Polarization dependence of the Schottky barrier height at a ferroelectric/electrode interface is also directly observed using XPS. (topical review - magnetism, magnetic materials, and interdisciplinary research)

  10. Vacuum energy referred Ti3+/4+ donor/acceptor states in insulating and semiconducting inorganic compounds

    International Nuclear Information System (INIS)

    Rogers, E.G.; Dorenbos, P.

    2014-01-01

    Optical spectroscopy data has been collected on the energy needed for electron transfer from the valence band to Ti 4+ in about 40 different insulating and II–VI and III–V semiconducting compounds. It provides a measure for the location of the Ti 3+ 3d 1 ground state level above the valence band. This is combined with the vacuum referred binding energy (VRBE) of valence band electrons as obtained with the chemical shift model based on lanthanide impurity spectroscopy. It provides the VRBE of an electron in the Ti 3+ ground state level. This work will first show that the energy of electron transfer to Ti 4+ is about the same as that to Eu 3+ irrespective of the type of compound. Next it will be shown that the VRBE of the Ti 3+ 3d 1 ground state is always near −4 eV. An approximately ±1 eV spread around that value is attributed to the crystal field splitting of the Ti 3+ 3d-levels. - Highlights: • Data on the energy of charge transfer (CT) to Ti 4+ in 38 compounds was collected. • A correlation between the Ti 4+ and Eu 3+ CT energies has been established. • The chemical shift model has been applied to Ti impurity states. • The Ti 3+ ground state binding energy is always around −4±1 eV

  11. Tunneling of self-trapped states and formation of a band

    International Nuclear Information System (INIS)

    Yonemitsu, K.

    1993-12-01

    Tunneling of a self-trapped kink and formation of a band are studied semi classically in the one-dimensional extended Peierls-Hubbard model near half filling, considering up to Gaussian fluctuations around imaginary-time-dependent periodic motion of electrons and phonons on the stationary phase of the action derived using Slater determinants. In the strong-coupling limit of both the Holstein and attractive Hubbard models, it reproduces analytically-known effective hopping of a single bipolaron because the tunneling involves only one in this limit. The method gives new results in other general cases and is easily applied to excited or more complex systems. 13 refs, 4 figs

  12. Variable Energy 2-MeV S-Band Linac for X-ray and Other Applications

    International Nuclear Information System (INIS)

    Howard Bender; Dave Schwellenbach; Ron Sturges; Rusty Trainham

    2008-01-01

    We will describe the design and operation of a compact, 2-MeV, S-band linear accelerator (linac) with variable energy tuning and short-pulse operation down to 15 ps with 100-A peak current. The design consists of a buncher cavity for short-pulse operation and two coupled resonator sections for acceleration. Single-pulse operation is accomplished through a fast injector system with a 219-MHz subharmonic buncher. The machine is intended to support a variety of applications, such as X-ray and electron beam diagnostic development and, recently, electron diffraction studies of phase transitions in shocked materials

  13. Calculations of Energy Shift of the Conduction Band-Edge in Doped and Compensated GaP

    OpenAIRE

    Endo, Tamio; Itoh, Nobuhiko; Okino, Yasushi; 遠藤, 民生; 伊藤, 伸彦; 沖野, 祥[他

    1989-01-01

    The energy shifts of the parabolic conduction band-edge at 77 and 300K with doping the Te-donor in GaP were calculated in the nondegenerate system for the two cases ; unintentional and intentional compensations, using the two models proposed by Hwang abd by Mahan. The total parabolic shift △EM(△EH), and the contributions of the exchangeinteraction △μex(△Ee) and of the Coulomb interaction △μed(△Ec) calculated by the Mahan's model (Hwang's model), increase with increasing donor concentration in...

  14. Variable Energy 2-MeV S-Band Linac for X-ray and Other Applications

    International Nuclear Information System (INIS)

    H. Bender; D. Schwellenbach; R. Sturges; R. Trainham

    2008-01-01

    This paper describes the design and operation of a compact, 2-MeV, S-band linear accelerator (linac) with variable energy tuning and short-pulse operation down to 15 ps with 100-A peak current. The design consists of a buncher cavity for short-pulse operation and two coupled resonator sections for acceleration. Single-pulse operation is accomplished through a fast injector system with a 219-MHz subharmonic buncher. The machine is intended to support a variety of applications, such as x-ray and electron beam diagnostic development, and recently, electron diffraction studies of phase transitions in shocked materials

  15. Search for the discrete non-yrast states in 152Dy around 86 ns isomer, the region into which the γ-rays drain the super-deformed band

    International Nuclear Information System (INIS)

    Mansour, N.

    1991-01-01

    Further analysis of the γ-ray study of 152 Dy emitted in the decay of the super-deformed band has been performed by using the 122 Sn ( 35 Cl, P4n) reaction at low bombarding energies. Several γ-rays de-exciting non-yrast states have been identified, among these are transitions previously observed in coincidence with this super-deformed band. The lowest two members of the super-deformed cascade have also been detected, but the data is not quite good enough to make a firm connection to them. (author)

  16. Harvesting Broad Frequency Band Blue Energy by a Triboelectric-Electromagnetic Hybrid Nanogenerator.

    Science.gov (United States)

    Wen, Zhen; Guo, Hengyu; Zi, Yunlong; Yeh, Min-Hsin; Wang, Xin; Deng, Jianan; Wang, Jie; Li, Shengming; Hu, Chenguo; Zhu, Liping; Wang, Zhong Lin

    2016-07-26

    Ocean wave associated energy is huge, but it has little use toward world energy. Although such blue energy is capable of meeting all of our energy needs, there is no effective way to harvest it due to its low frequency and irregular amplitude, which may restrict the application of traditional power generators. In this work, we report a hybrid nanogenerator that consists of a spiral-interdigitated-electrode triboelectric nanogenerator (S-TENG) and a wrap-around electromagnetic generator (W-EMG) for harvesting ocean energy. In this design, the S-TENG can be fully isolated from the external environment through packaging and indirectly driven by the noncontact attractive forces between pairs of magnets, and W-EMG can be easily hybridized. Notably, the hybrid nanogenerator could generate electricity under either rotation mode or fluctuation mode to collect energy in ocean tide, current, and wave energy due to the unique structural design. In addition, the characteristics and advantages of outputs indicate that the S-TENG is irreplaceable for harvesting low rotation speeds (10 Hz). The complementary output can be maximized and hybridized for harvesting energy in a broad frequency range. Finally, a single hybrid nanogenerator unit was demonstrated to harvest blue energy as a practical power source to drive several LEDs under different simulated water wave conditions. We also proposed a blue energy harvesting system floating on the ocean surface that could simultaneously harvest wind, solar, and wave energy. The proposed hybrid nanogenerator renders an effective and sustainable progress in practical applications of the hybrid nanogenerator toward harvesting water wave energy offered by nature.

  17. Energy drinks in the Gulf Cooperation Council states: A review

    OpenAIRE

    Alhyas, Layla; El Kashef, Ahmed; AlGhaferi, Hamad

    2015-01-01

    Energy drinks have become a popular beverage worldwide. This review was carried out to have an overview among adolescents and emerging adults in the Gulf Co-operation Council states about energy drinks consumption rates and other related issues such as starting age and patterns of energy drink consumption. The Medline and Embase databases were searched separately using different terms such as energy drinks, energy beverages, and caffeinated drinks. Data related to the rates of energy drinks u...

  18. A Cross-Cultural Examination of University Students' Motivation toward Band and Academics in Singapore and the United States

    Science.gov (United States)

    Tan, Leonard; Miksza, Peter

    2018-01-01

    The purpose of the study was to investigate how university band students' (non--music majors) motivational goal orientations toward band and academics differ across participants from Singapore (n = 200) and the United States (n = 227) and examine how they relate to a suite of adaptive dispositions (i.e., flow, grit, and commitment) relevant for…

  19. Energy Balance of the Santa Catarina State - Series 1980 -1996

    International Nuclear Information System (INIS)

    1997-01-01

    This energy balance of the Santa Catarina State presents the following main topics that can be outstanding: economic aspects; supply and demand of energy by source 1980-1996; energy consumption by sector 1980/1996; energy interchange; and balance of the transformation centers 1980/1996

  20. Reconstructing the energy band electronic structure of pulsed laser deposited CZTS thin films intended for solar cell absorber applications

    Science.gov (United States)

    Pandiyan, Rajesh; Oulad Elhmaidi, Zakaria; Sekkat, Zouheir; Abd-lefdil, Mohammed; El Khakani, My Ali

    2017-02-01

    We report here on the use of pulsed KrF-laser deposition (PLD) technique for the growth of high-quality Cu2ZnSnS4 (CZTS) thin films onto Si, and glass substrates without resorting to any post sulfurization process. The PLD-CZTS films were deposited at room temperature (RT) and then subjected to post annealing at different temperatures ranging from 200 to 500 °C in Argon atmosphere. The X-ray diffraction and Raman spectroscopy confirmed that the PLD films crystallize in the characteristic kesterite CZTS structure regardless of their annealing temperature (Ta), but their crystallinity is much improved for Ta ≥ 400 °C. The PLD-CZTS films were found to exhibit a relatively dense morphology with a surface roughness (RMS) that increases with Ta (from ∼14 nm at RT to 70 nm at Ta = 500 °C with a value around 40 nm for Ta = 300-400 °C). The optical bandgap of the PLD-CZTS films, was derived from UV-vis transmission spectra analysis, and found to decrease from 1.73 eV for non-annealed films to ∼1.58 eV for those annealed at Ta = 300 °C. These band gap values are very close to the optimum value needed for an ideal solar cell absorber. In order to achieve a complete reconstruction of the one-dimensional energy band structure of these PLD-CZTS absorbers, we have combined both XPS and UPS spectroscopies to determine their chemical bondings, the position of their valence band maximum (relative to Fermi level), and their work function values. This enabled us to sketch out, as accurately as possible, the band alignment of the heterojunction interface formed between CZTS and both CdS and ZnS buffer layer materials.

  1. Direct band gap measurement of Cu(In,Ga)(Se,S)2 thin films using high-resolution reflection electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Heo, Sung; Lee, Hyung-Ik; Park, Jong-Bong; Ko, Dong-Su; Chung, JaeGwan; Kim, KiHong; Kim, Seong Heon; Yun, Dong-Jin; Ham, YongNam; Park, Gyeong Su; Song, Taewon; Lee, Dongho; Nam, Junggyu; Kang, Hee Jae; Choi, Pyung-Ho; Choi, Byoung-Deog

    2015-01-01

    To investigate the band gap profile of Cu(In 1−x ,Ga x )(Se 1−y S y ) 2 of various compositions, we measured the band gap profile directly as a function of in-depth using high-resolution reflection energy loss spectroscopy (HR-REELS), which was compared with the band gap profile calculated based on the auger depth profile. The band gap profile is a double-graded band gap as a function of in-depth. The calculated band gap obtained from the auger depth profile seems to be larger than that by HR-REELS. Calculated band gaps are to measure the average band gap of the spatially different varying compositions with respect to considering its void fraction. But, the results obtained using HR-REELS are to be affected by the low band gap (i.e., out of void) rather than large one (i.e., near void). Our findings suggest an analytical method to directly determine the band gap profile as function of in-depth

  2. Direct band gap measurement of Cu(In,Ga)(Se,S){sub 2} thin films using high-resolution reflection electron energy loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Sung [Analytical Engineering Group, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); College of Information and Communication Engineering, Sungkyunkwan University, Cheoncheon-dong 300, Jangan-gu, Suwon 440-746 (Korea, Republic of); Lee, Hyung-Ik; Park, Jong-Bong; Ko, Dong-Su; Chung, JaeGwan; Kim, KiHong; Kim, Seong Heon; Yun, Dong-Jin; Ham, YongNam; Park, Gyeong Su [Analytical Engineering Group, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); Song, Taewon [Energy lab, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); Lee, Dongho, E-mail: dhlee0333@gmail.com; Nam, Junggyu [PV Development Team, Energy Solution Business Division, Samsung SDI, 467 Beonyeong-ro, Cheonan-si, Chungcheongnam-do 331-330 (Korea, Republic of); Kang, Hee Jae [Department of Physics, Chungbuk National University, Gaesin-dong, Heungdeok-gu, Cheongju, 361-763 (Korea, Republic of); Choi, Pyung-Ho; Choi, Byoung-Deog, E-mail: bdchoi@skku.edu [College of Information and Communication Engineering, Sungkyunkwan University, Cheoncheon-dong 300, Jangan-gu, Suwon 440-746 (Korea, Republic of)

    2015-06-29

    To investigate the band gap profile of Cu(In{sub 1−x},Ga{sub x})(Se{sub 1−y}S{sub y}){sub 2} of various compositions, we measured the band gap profile directly as a function of in-depth using high-resolution reflection energy loss spectroscopy (HR-REELS), which was compared with the band gap profile calculated based on the auger depth profile. The band gap profile is a double-graded band gap as a function of in-depth. The calculated band gap obtained from the auger depth profile seems to be larger than that by HR-REELS. Calculated band gaps are to measure the average band gap of the spatially different varying compositions with respect to considering its void fraction. But, the results obtained using HR-REELS are to be affected by the low band gap (i.e., out of void) rather than large one (i.e., near void). Our findings suggest an analytical method to directly determine the band gap profile as function of in-depth.

  3. Energy matrix in the Parana State. Year 2000

    International Nuclear Information System (INIS)

    1994-01-01

    The energy sector in the Parana State, Brazil, is analyzed. The supply, demand, investment, environmental, social and economic aspects are described, and the necessary action for satisfying the energy demand in the year 2000 are presented. 69 tabs., 11 figs

  4. Eastern States Harness Clean Energy to Promote Air Quality

    Energy Technology Data Exchange (ETDEWEB)

    2007-10-01

    States on the East Coast are including renewable energy and energy efficiency projects into their air quality plans that they submit to the EPA to address nonattainment for nitrogen oxides and other pollutants.

  5. Energy balance of the Sao Paulo State - 1990

    International Nuclear Information System (INIS)

    1992-01-01

    This document informs the energetic balance for Sao Paulo State - 1990, with information referring to the year 1989, containing the energy fluxes from primary and secondary energy sources in the main sectors of Sao Paulo economy. 32 figs., 99 tabs

  6. The transition between energy efficient and energy inefficient states in Cameroon

    International Nuclear Information System (INIS)

    Adom, Philip Kofi

    2016-01-01

    I use a two-state (energy efficient/inefficient) Markov-switching dynamic model to study energy efficiency in Cameroon in a novel manner, employing yearly data covering 1971 to 2012. I find that the duration of an energy inefficient state is about twice as long as an energy efficient state, mainly due to fuel subsidies, low income, high corruption, regulatory inefficiencies, poorly developed infrastructure and undeveloped markets. To escape from an energy inefficient state a broad policy overhaul is needed. Trade liberalization and related growth policies together with the removal of fuel subsidies are useful, but insufficient policy measures; the results suggest that they should be combined with structural policies, aiming at institutional structure and investment in infrastructure. - Highlights: • I investigate the transition between energy efficient/inefficient states. • On the average, energy inefficient state persists more than energy efficient state. • The duration of energy inefficient state is about twice as long as energy efficient state. • Price, income and trade openness have distinct energy saving effect irrespective of state. • A broad policy overhaul is needed to escape the energy inefficient state.

  7. The Energy Puzzle Between the United States and China

    Science.gov (United States)

    2013-03-01

    securing China’s status as a great power.2 As of 2011, China is the second largest consumer of natural resources (oil, liquefied petroleum gas ( LPG ...pursuit of natural resources, (oil, natural gas , coal or renewable energy sources) is reshaping the world’s energy security. The United States is...pursuit of natural resources, (oil, natural gas , coal or renewable energy sources) is reshaping the world’s energy security. The United States is

  8. Global energy outlooks. State of the art

    International Nuclear Information System (INIS)

    Bobin, J.L.; Nifenecker, H.; Stephan, C.

    1999-01-01

    Since two year, the SFP (French Society of Physics) began a debate on the Energy of the 21 century, by the way of regional conferences. This debate allowed the publication of synthesis documents about elements discussed during these conference. This document presents the foreseeable evolution of the energy demand, taking into account the reserves; the selected production forms consequences in terms of nuisances; the part of the nuclear energy and the renewable energies. The costs are also discussed and many statistical data are provided. (A.L.B.)

  9. High energy physics in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Month, M.

    1985-10-16

    The US program in high energy physics from 1985 to 1995 is reviewed. The program depends primarily upon work at the national accelerator centers, but includes a modest but diversified nonaccelerator program. Involvement of universities is described. International cooperation in high energy physics is discussed, including the European, Japanese, USSR, and the People's Republic of China's programs. Finally, new facilities needed by the US high energy physics program are discussed, with particular emphasis given to a Superconducting Super Collider for achieving ever higher energies in the 20 TeV range. (LEW)

  10. High energy physics in the United States

    International Nuclear Information System (INIS)

    Month, M.

    1985-01-01

    The US program in high energy physics from 1985 to 1995 is reviewed. The program depends primarily upon work at the national accelerator centers, but includes a modest but diversified nonaccelerator program. Involvement of universities is described. International cooperation in high energy physics is discussed, including the European, Japanese, USSR, and the People's Republic of China's programs. Finally, new facilities needed by the US high energy physics program are discussed, with particular emphasis given to a Superconducting Super Collider for achieving ever higher energies in the 20 TeV range

  11. Energy balance from Bahia state 2011 - series: 1994-2010

    International Nuclear Information System (INIS)

    2011-01-01

    The present Energy Balance is constituted of six chapters, as follows: the chapter 1 approaches the profile of the energy system, showing the structure of the Bahia state energy matrix i n the year of 2010, and the modifications occurred during the period of 1994-2010; the chapter 2 analyses the evolution during the period of 1994-2010 of the energy offer with aspects of production, exports, imports and consumption; the chapter 3 comprised the evolution of energy consumption by sources and social-economic sectors; chapter 4 focus the evolution of state energy self-sufficiency, confronting the primary energy production with the energy total demand; the chapter 5 contains the balance of the energy transformation centers of the Bahia state; and the chapter 6 contains the consolidated matrixes expressed in the period of 1980, 1985 and 1990-2010

  12. Band-gap-confinement and image-state-recapture effects in the survival of anions scattered from metal surfaces

    International Nuclear Information System (INIS)

    Schmitz, Andrew; Shaw, John; Chakraborty, Himadri S.; Thumm, Uwe

    2010-01-01

    The resonant charge transfer process in the collision of hydrogen anions with metal surfaces is described within a single-active-electron wave-packet propagation method. The ion-survival probability is found to be strongly enhanced at two different surface-specific perpendicular velocities of the ion. It is shown that, while the low-velocity enhancement is induced from a dynamical confinement of the ion level inside the band gap, the high-velocity enhancement is due to electron recapture from transiently populated image states. Results are presented for Li(110), Cu(111), and Pd(111) surfaces.

  13. Intermediate-band photosensitive device with quantum dots embedded in energy fence barrier

    Science.gov (United States)

    Forrest, Stephen R.; Wei, Guodan

    2010-07-06

    A plurality of layers of a first semiconductor material and a plurality of dots-in-a-fence barriers disposed in a stack between a first electrode and a second electrode. Each dots-in-a-fence barrier consists essentially of a plurality of quantum dots of a second semiconductor material embedded between and in direct contact with two layers of a third semiconductor material. Wave functions of the quantum dots overlap as at least one intermediate band. The layers of the third semiconductor material are arranged as tunneling barriers to require a first electron and/or a first hole in a layer of the first material to perform quantum mechanical tunneling to reach the second material within a respective quantum dot, and to require a second electron and/or a second hole in a layer of the first semiconductor material to perform quantum mechanical tunneling to reach another layer of the first semiconductor material.

  14. Manipulation of resonant tunneling by substrate-induced inhomogeneous energy band gaps in graphene with square superlattice potentials

    International Nuclear Information System (INIS)

    Li, Guanqiang; Chen, Guangde; Peng, Ping; Cao, Zhenzhou; Ye, Honggang

    2013-01-01

    We investigate the resonant transmission of Dirac electrons through inhomogeneous band gap graphene with square superlattice potentials by transfer matrix method. The effects of the incident angle of the electrons, Fermi energy and substrate-induced Dirac gaps on the transmission are considered. It is found that the Dirac gap of graphene adds another degree of freedom with respect to the incident angle, the Fermi energy and the parameters of periodic superlattice potentials (i.e., the number, width and height of the barriers) for the transmission. In particular, the inhomogeneous Dirac gap induced by staggered substrates can be used to manipulate the transmission. The properties of the conductance and Fano factor at the resonant peaks are found to be affected by the gaps significantly. The results may be helpful for the practical application of graphene-based electronic devices

  15. Determination of energy band diagram and charge carrier mobility of white emitting polymer from optical, electrical and impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mohd Sarjidan, M.A., E-mail: mohd.arif@um.edu.my; Mohd Mokhtar, H.A.; Abd Majid, W.H., E-mail: q3haliza@um.edu.my

    2015-03-15

    A single-layer white polymer light-emitting device (WPLED) has been fabricated using spin coating technique. The device was constructed as ITO/PEDOT:PSS(50 nm)/SPW-111(50 nm)/LiF(1 nm)/Al(100 nm). Indium tin oxide (ITO) and poly(3,4-ethylenedioxythiophene) Polystyrene sulfonate (PEDOT:PSS) are used as the transparent anode. SPW-111 is fabricated as a white emissive layer and lithium fluoride (LiF) and aluminum (Al) are used as reflecting cathode. Energy band diagram of the device was estimated from a combination of ultraviolet–visible (UV–vis) and current–voltage (J–V) analyses. Charge carrier mobility (μ) of PLED was evaluated using negative differential susceptance (−ΔB) method from impedance spectroscopy (IS) analysis. The calculated μ of the SPW-111 device is in the magnitude of 10{sup −6} cm{sup 2}/V/s. - Highlights: • Single layer PLED has been fabricated with spin-coating technique and device performance has been evaluated. • Energy band diagram of the SPW-111 is estimated from optical and electrical analyses. • Charge carrier mobility of the SPW-111 materials is obtained by impedance spectroscopy.

  16. Enhanced Water Splitting by Fe2O3-TiO2-FTO Photoanode with Modified Energy Band Structure

    Directory of Open Access Journals (Sweden)

    Eul Noh

    2013-01-01

    Full Text Available The effect of TiO2 layer applied to the conventional Fe2O3/FTO photoanode to improve the photoelectrochemical performance was assessed from the viewpoint of the microstructure and energy band structure. Regardless of the location of the TiO2 layer in the photoanodes, that is, Fe2O3/TiO2/FTO or TiO2/Fe2O3/FTO, high performance was obtained when α-Fe2O3 and H-TiNT/anatase-TiO2 phases existed in the constituent Fe2O3 and TiO2 layers after optimized heat treatments. The presence of the Fe2O3 nanoparticles with high uniformity in the each layer of the Fe2O3/TiO2/FTO photoanode achieved by a simple dipping process seemed to positively affect the performance improvement by modifying the energy band structure to a more favorable one for efficient electrons transfer. Our current study suggests that the application of the TiO2 interlayer, together with α-Fe2O3 nanoparticles present in the each constituent layers, could significantly contribute to the performance improvement of the conventional Fe2O3 photoanode.

  17. Development of wide-band, time and energy resolving, optical photon detectors with application to imaging astronomy

    International Nuclear Information System (INIS)

    Miller, A.J.; Cabrera, B.; Romani, R.W.; Figueroa-Feliciano, E.; Nam, S.W.; Clarke, R.M.

    2000-01-01

    Superconducting transition edge sensors (TESs) are showing promise for the wide-band spectroscopy of individual photons from the mid-infrared (IR), through the optical, and into the near ultraviolet (UV). Our TES sensors are ∼20 μm square, 40 nm thick tungsten (W) films with a transition temperature of about 80 mK. We typically attain an energy resolution of 0.15 eV FWHM over the optical range with relative timing resolution of 100 ns. Single photon events with sub-microsecond risetimes and few microsecond falltimes have been achieved allowing count rates in excess of 30 kHz per pixel. Additionally, tungsten is approximately 50% absorptive in the optical (dropping to 10% in the IR) giving these devices an intrinsically high quantum efficiency. These combined traits make our detectors attractive for fast spectrophotometers and photon-starved applications such as wide-band, time and energy resolved astronomical observations. We present recent results from our work toward the fabrication and testing of the first TES optical photon imaging arrays

  18. Workplace Energy Conservation at Michigan State University

    Science.gov (United States)

    Allen, Summer; Marquart-Pyatt, Sandra T.

    2018-01-01

    Purpose: This research contributes to the literature on workplace energy conservation by examining the predictors of individual employee behaviors and policy support in a university. The purpose of this research is to better understand what factors influence energy conservation behaviors in this setting to inform programs and interventions.…

  19. Decay out of the yrast superdeformed band in 191Hg

    International Nuclear Information System (INIS)

    Sien, S.; Reiter, P.; Khoo, T.; Lauritsen, T.; Carpenter, M. P.; Ahmad, I.; Amro, H.; Calderin, I.; Dossing, T.; Fischer, S. M.; Garg, U.; Gassmann, D.; Hackman, G.; Hannachi, F.; Janssens, R. V. F.; Kharraja, B.; Korichi, A.; Lopez-Martens, A.; Moore, E. F.; Nisius, D.; Schuck, C.

    1999-01-01

    The excitation energies and spins of the yrast superdeformed band in 191 Hg have been determined by analyzing the quasicontinuum spectrum connecting the superdeformed and normal-deformed states. The results from this analysis, combined with that given by one-step decay lines, give confident assignments of the spins and energies of the yrast superdeformed band in 191 Hg

  20. Band-head spectra of low-energy single-particle excitations in some well-deformed, odd-mass heavy nuclei within a microscopic approach

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Meng-Hock [Universiti Teknologi Malaysia, Skudai, Johor (Malaysia); Univ. Bordeaux, CENBG, UMR5797, Gradignan (France); CNRS, IN2P3, CENBG, UMR5797, Gradignan (France); Duc, Dao Duy [Ton Duc Thang University, Division of Nuclear Physics, Ho Chi Minh City (Viet Nam); Ton Duc Thang University, Faculty of Applied Sciences, Ho Chi Minh City (Viet Nam); Nhan Hao, T.V. [Duy Tan University, Center of Research and Development, Danang (Viet Nam); Hue University, Center for Theoretical and Computational Physics, College of Education, Hue City (Viet Nam); Long, Ha Thuy [Hanoi University of Sciences, Vietnam National University, Hanoi (Viet Nam); Quentin, P. [Universiti Teknologi Malaysia, Skudai, Johor (Malaysia); Univ. Bordeaux, CENBG, UMR5797, Gradignan (France); CNRS, IN2P3, CENBG, UMR5797, Gradignan (France); Ton Duc Thang University, Division of Nuclear Physics, Ho Chi Minh City (Viet Nam); Bonneau, L. [Univ. Bordeaux, CENBG, UMR5797, Gradignan (France); CNRS, IN2P3, CENBG, UMR5797, Gradignan (France)

    2016-01-15

    In four well-deformed heavy odd nuclei, the energies of low-lying rotational band heads have been determined microscopically within a self-consistent Hartree-Fock-plus-BCS approach with blocking. A Skyrme nucleon-nucleon effective interaction has been used together with a seniority force to describe pairing correlations. Only such states which are phenomenologically deemed to be related to single-particle excitations have been considered. The polarization effects, including those associated with the genuine time-reversal symmetry breaking have been fully taken into account within our model assumptions. The calculated spectra are in reasonably good qualitative agreement with available data for the considered odd-neutron nuclei. This is not so much the case for the odd-proton nuclei. A potential explanation for such a difference in behavior is proposed. (orig.)

  1. A coaxial double cylindrical TEPC for the microdosimetry of selected neutron energy bands in mixed fields of fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Saion, E.B.; Watt, D.E. (Saint Andrews Univ. (UK). Dept. of Physics); East, B.W. (Scottish Universities Research and Reactor Centre, Glasgow (UK)); Colautti, P. (Istituto Nazionale di Fisica Nucleare, Padua (Italy))

    1990-01-01

    A new low pressure tissue-equivalent proportional counter (TEPC) in a coaxial double cylindrical form has been developed to measure separately the microdose spectrum from any desired energy band of neutrons in the presence of mixed fields of faster neutrons, by selecting the thickness of the common TE dividing wall to be equivalent to the corresponding maximum proton ranges and by appropriate use of coincidence/anti-coincidence pulse arrangements. This thickness ensures charged particle equilibrium for the relevant neutron energy. Event spectra due to recoils generated by faster neutrons which interact with both the counters are removed completely by anti-coincidence techniques, thereby optimising the sensitivity of the inner microdosemeter to the event spectra of interest. The ability of this counter to discriminate in favour of events due to neutrons of energy <850 keV was achieved in microdosimetric measurements from mixed fields of a nuclear reactor. Mean values of lineal energy and quality factor for neutrons of energy <850 keV from a nuclear reactor were determined from the anti-coincidence spectrum. Good discrimination against {gamma} ray induced events is also achieved for the spectrum recorded in the anti-coincidence mode. This is an advantageous feature for other applications and requires further investigation. (author).

  2. A coaxial double cylindrical TEPC for the microdosimetry of selected neutron energy bands in mixed fields of fast neutrons

    International Nuclear Information System (INIS)

    Saion, E.B.; Watt, D.E.; Colautti, P.

    1990-01-01

    A new low pressure tissue-equivalent proportional counter (TEPC) in a coaxial double cylindrical form has been developed to measure separately the microdose spectrum from any desired energy band of neutrons in the presence of mixed fields of faster neutrons, by selecting the thickness of the common TE dividing wall to be equivalent to the corresponding maximum proton ranges and by appropriate use of coincidence/anti-coincidence pulse arrangements. This thickness ensures charged particle equilibrium for the relevant neutron energy. Event spectra due to recoils generated by faster neutrons which interact with both the counters are removed completely by anti-coincidence techniques, thereby optimising the sensitivity of the inner microdosemeter to the event spectra of interest. The ability of this counter to discriminate in favour of events due to neutrons of energy <850 keV was achieved in microdosimetric measurements from mixed fields of a nuclear reactor. Mean values of lineal energy and quality factor for neutrons of energy <850 keV from a nuclear reactor were determined from the anti-coincidence spectrum. Good discrimination against γ ray induced events is also achieved for the spectrum recorded in the anti-coincidence mode. This is an advantageous feature for other applications and requires further investigation. (author)

  3. Hydrostatic pressure effects on the {gamma}-X conduction band mixing and the binding energy of a donor impurity in GaAs-Ga{sub 1-x}Al{sub x}As quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Duque, C.A. [Instituto de Fisica, Universidad de Antioquia, AA 1226, Medellin (Colombia); Lopez, S.Y. [Facultad de Educacion, Universidad de Antioquia, AA 1226, Medellin (Colombia); Mora-Ramos, M.E. [Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, C.P. 62210, Cuernavaca (Mexico)

    2007-06-15

    Mixing between {gamma} and X valleys of the conduction band in GaAs-Ga{sub 1-x}Al{sub x}As quantum wells is investigated taken into account the effect of applied hydrostatic pressure. This effect is introduced via the pressure-dependent values of the corresponding energy gaps and the main band parameters. The mixing is considered along the lines of a phenomenological model. Variation of the confined ground state in the well as a function of the pressure is reported. The dependencies of the variationally calculated binding energy of a donor impurity with the hydrostatic pressure and well width are also presented. It is shown that the inclusion of the {gamma}-X mixing explains the non-linear behavior in the photoluminescence peak of confined exciton states that has been observed for pressures above 20 kbar. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Steady-state emission of blazars at very high energies

    Energy Technology Data Exchange (ETDEWEB)

    Hoehne-Moench, Daniel

    2010-07-01

    of the individual objects shows a clear shift to positive values, a stacking method was applied to the sample. For the whole set of 20 objects, an excess of {gamma}-rays was found with a significance of 4.5 standard deviations in 349.5 hours of effective exposure time. For the first time a signal stacking in the VHE regime turned out to be successful. The measured integral flux from the cumulative signal corresponds to 1.4% of the Crab Nebula flux above 150 GeV with a spectral index {alpha}=-3.15{+-}0.57. None of the objects showed any significant variability during the observation time and therefore the detected signal can be interpreted as the baseline emission of these objects. For the individual objects lower limits on the broad-band spectral indices {alpha}{sub X-{gamma}} between the X-ray range at 1 keV and the VHE {gamma}- ray regime at 200 GeV were calculated. The majority of objects show a spectral behaviour as expected from the source class of HBLs: The energy output in the VHE regime is in general lower than in X-rays. For the stacked blazar sample the broad-band spectral index was calculated to {alpha}{sub X-{gamma}}=1.09, confirming the result found for the individual objects. Another evidence for the revelation of the baseline emission is the broad-band spectral energy distribution (SED) comprising archival as well as contemporaneous multi-wavelength data from the radio to the VHE band. The SEDs of known VHE {gamma}-ray sources in low flux states matches well the SED of the stacked blazar sample. (orig.)

  5. Quantum dynamical study of low-energy photoelectron bands of 2 ...

    Indian Academy of Sciences (India)

    gated theoretically, paying particular attention to the vibrational structure and to possible nonadiabatic coupling effects. ... the ground state, to the excitation of non-totally sym- ... (PENNA; see figure 1 for a schematic representation) has been ...

  6. Neutrino mixing, flavor states and dark energy

    International Nuclear Information System (INIS)

    Blasone, M.; Capolupo, A.; Capozziello, S.; Vitiello, G.

    2008-01-01

    We shortly summarize the quantum field theory formalism for the neutrino mixing and report on recent results showing that the vacuum condensate induced by neutrino mixing can be interpreted as a dark energy component of the Universe

  7. Huge operation by energy gap of novel narrow band gap Tl1-x In1-x B x Se2 (B = Si, Ge): DFT, x-ray emission and photoconductivity studies

    Science.gov (United States)

    Piasecki, M.; Myronchuk, G. L.; Zamurueva, O. V.; Khyzhun, O. Y.; Parasyuk, O. V.; Fedorchuk, A. O.; Albassam, A.; El-Naggar, A. M.; Kityk, I. V.

    2016-02-01

    It is shown that narrow band gap semiconductors Tl1-x In1-x GexSe2 are able effectively to vary the values of the energy gap. DFT simulations of the principal bands during the cationic substitutions is done. Changes of carrier transport features is explored. Relation with the changes of the near the surface states is explored . Comparison on a common energy scale of the x-ray emission Se Kβ 2 bands, representing energy distribution of the Se 4p states, indicates that these states contribute preliminary to the top of the valence band. The temperature dependence of electrical conductivity and spectral dependence photoconductivity for the Tl1-x In1-x Ge x Se2 and Tl1-x In1-x Si x Se2 single crystals were explored and compared with previously reported Tl1-x In1-x Sn x Se2. Based on our investigations, a model of centre re-charging is proposed. Contrary to other investigated crystals in Tl1-x In1-x Ge x Se2 single crystals for x = 0.1 we observe extraordinarily enormous photoresponse, which exceed more than nine times the dark current. X-ray photoelectron core-level and valence-band spectra for pristine and Ar+-ion irradiated surfaces of Tl1-x In1-x GexSe2 (x = 0.1 and 0.2) single crystals have been studied. These results indicate that the relatively low hygroscopicity of the studied single crystals is typical for the Tl1-x In1-x Ge x Se2 crystals, a property that is very important for handling these quaternary selenides as infrared materials operating at ambient conditions.

  8. Role of band states and trap states in the electrical properties of organic semiconductors: Hopping versus mobility edge model

    KAUST Repository

    Mehraeen, Shafigh; Coropceanu, Veaceslav; Bré das, Jean-Luc

    2013-01-01

    We compare the merits of a hopping model and a mobility edge model in the description of the effect of charge-carrier concentration on the electrical conductivity, carrier mobility, and Fermi energy of organic semiconductors. We consider the case

  9. Coral transcriptome and bacterial community profiles reveal distinct Yellow Band Disease states in Orbicella faveolata

    KAUST Repository

    Closek, Collin J.; Sunagawa, Shinichi; DeSalvo, Michael K.; Piceno, Yvette M.; Desantis, Todd Z.; Brodie, Eoin L.; Weber, Michele X.; Voolstra, Christian R.; Andersen, Gary L.; Medina, Mó nica M.

    2014-01-01

    marked each health state. Diseased samples were associated with two to three times more bacterial diversity. HD samples had the highest bacterial richness, which included components associated with HH and DD, as well as additional unique families

  10. The quest for EEG power band correlation with ICA derived fMRI resting state networks

    NARCIS (Netherlands)

    Meyer, M.C.; Janssen, R.J.; van Oort, E.S.B.; Beckmann, Christian; Barth, M.

    2013-01-01

    The neuronal underpinnings of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) resting state networks (RSNs) are still unclear. To investigate the underlying mechanisms, specifically the relation to the electrophysiological signal, we used simultaneous recordings of

  11. Simple vertex correction improves GW band energies of bulk and two-dimensional crystals

    DEFF Research Database (Denmark)

    Schmidt, Per Simmendefeldt; Patrick, Christopher E.; Thygesen, Kristian Sommer

    2017-01-01

    The GW self-energy method has long been recognized as the gold standard for quasiparticle (QP) calculations of solids in spite of the fact that the neglect of vertex corrections and the use of a density-functional theory starting point lack rigorous justification. In this work we remedy this situ......The GW self-energy method has long been recognized as the gold standard for quasiparticle (QP) calculations of solids in spite of the fact that the neglect of vertex corrections and the use of a density-functional theory starting point lack rigorous justification. In this work we remedy...

  12. Band Jahn-Teller effect on the density of states of the magnetic high-Tc superconductors: A model study

    International Nuclear Information System (INIS)

    Pradhan, B.; Mohanta, K.L.; Rout, G.C.

    2012-01-01

    We report here a mean-field study of competing antiferromagnetism, superconductivity and lattice strain phases and their effect on the local density of states of the cuprate system. Our model Hamiltonian incorporating these interactions is reported earlier [G.C. Rout et al., Physica C, 2007]. The analytic expression for superconducting, antiferromagnetism and lattice strain order parameters are calculated and solved self-consistently. The interplay of these order parameters is investigated considering the calculated density of states (DOSs) of the conduction electrons. The DOS displays multiple gap structures with multiple peaks. It is suggested that the tunneling conductance data obtained from the scanning tunneling microscopy (STM) measurements could be interpreted by using the quasi-particle bands calculated from our model Hamiltonian. We have discussed the mechanism to calculate the order parameters from the conductance data.

  13. Visualizing band offsets and edge states in bilayer–monolayer transition metal dichalcogenides lateral heterojunction

    KAUST Repository

    Zhang, Chendong

    2016-01-18

    Semiconductor heterostructures are fundamental building blocks for many important device applications. The emergence of two-dimensional semiconductors opens up a new realm for creating heterostructures. As the bandgaps of transition metal dichalcogenides thin films have sensitive layer dependence, it is natural to create lateral heterojunctions (HJs) using the same materials with different thicknesses. Here we show the real space image of electronic structures across the bilayer–monolayer interface in MoSe2 and WSe2, using scanning tunnelling microscopy and spectroscopy. Most bilayer–monolayer HJs are found to have a zig-zag-orientated interface, and the band alignment of such atomically sharp HJs is of type-I with a well-defined interface mode that acts as a narrower-gap quantum wire. The ability to utilize such commonly existing thickness terraces as lateral HJs is a crucial addition to the tool set for device applications based on atomically thin transition metal dichalcogenides, with the advantage of easy and flexible implementation.

  14. Solid state Ka-band pulse oscillator with frequency electronic switching

    Directory of Open Access Journals (Sweden)

    Dvornichenko V. P.

    2015-08-01

    Full Text Available Transmitting devices for small radars in the millimeter wavelength range with high resolution on range and noise immunity. The work presents the results of research and development of compact pulse oscillators with digital frequency switching from pulse to pulse. The oscillator consists of a frequency synthesizer and a synchronized amplifier on the IMPATT diode. Reference oscillator of synthesizer is synchronized by crystal oscillator with digital PLL system and contains a frequency multiplier and an amplifier operating in pulse mode. Small-sized frequency synthesizer of 8 mm wave lengths provides an output power of ~1.2 W per pulse with a frequency stability of no worse than 2•10–6. Radiation frequency is controlled by three-digit binary code in OOL levels. Synchronized amplifier made on IMPATT diodes provides microwave power up to 20 W in oscillator output with microwave pulse duration of 100—300 ns in an operating band. The oscillator can be used as a driving source for the synchronization of semiconductor and electro-vacuum devices of pulsed mode, and also as a transmitting device for small-sized radar of millimeter wave range.

  15. Energy Band Structure Studies Of Zinc-Blende GaAs and InAs ...

    African Journals Online (AJOL)

    A self-consistent calculation of the structural and electronic properties of zinc blende GaAs and InAs has been carried out. The calculations were done using the full potential-linearized augmented plane wave (FPLAPW) method within the density functional theory (DFT). The exchange-correlation energy used is the ...

  16. Electron densities and chemical bonding in TiC, TiN and TiO derived from energy band calculations

    International Nuclear Information System (INIS)

    Blaha, P.

    1983-10-01

    It was the aim of this paper to describe the chemical bonding of TiC, TiN and TiO by means of energy bands and electron densities. Using the respective potentials we have calculated the bandstructure of a finer k-grid with the linearized APW method to obtain accurate densities of states (DOS). These DOS wer partitioned into local partial contributions and the metal d DOS were further decomposed into tsub(2g) and esub(g) symmetry components in order to additionally characterize bonding. The electron densities corresponding to the occupied valence states are obtained from the LAPW calculations. They provide further insight into characteristic trends in the series from TiC to TiO: around the nonmetal site the density shows increasing localisation; around the metal site the deviation from spherical symmetry changes from esub(g) to tsub(2g). Electron density plots of characteristic band states allow to describe different types of bonding occurring in these systems. For TiC and TiN recent measurements of the electron densities exist for samples of TiCsub(0.94) and TiNsub(0.99), where defects cause static displacements of the Ti atoms. If this effect can be compensated by an atomic model one hopefully can extrapolate to stoichiometric composition. This procedure allows a comparison with structure factors derived from theoretical electron densities. The agreement for TiN is very good. For TiC the extrapolated data agree in terms of the deviations from spherical symmetry near the Ti site with the LAPW data, but the densities around both atoms are more localized than in theory. An explanation could be: a) the defects affect the electronic structure in TiCsub(0.94) with respect to TiCsub(1.0): b) the applied atomic model does not properly extrapolate to stoichiometry, because parameters of this model correlate or become unphysical. (Author)

  17. Efficient full-spectrum utilization, reception and conversion of solar energy by broad-band nanospiral antenna.

    Science.gov (United States)

    Zhao, Huaqiao; Gao, Huotao; Cao, Ting; Li, Boya

    2018-01-22

    In this work, the collection of solar energy by a broad-band nanospiral antenna is investigated in order to solve the low efficiency of the solar rectenna based on conventional nanoantennas. The antenna impedance, radiation, polarization and effective area are all considered in the efficiency calculation using the finite integral technique. The wavelength range investigated is 300-3000 nm, which corresponds to more than 98% of the solar radiation energy. It's found that the nanospiral has stronger field enhancement in the gap than a nanodipole counterpart. And a maximum harvesting efficiency about 80% is possible in principle for the nanospiral coupled to a rectifier resistance of 200 Ω, while about 10% for the nanodipole under the same conditions. Moreover, the nanospiral could be coupled to a rectifier diode of high resistance more easily than the nanodipole. These results indicate that the efficient full-spectrum utilization, reception and conversion of solar energy can be achieved by the nanospiral antenna, which is expected to promote the solar rectenna to be a promising technology in the clean, renewable energy application.

  18. Country Report on Building Energy Codes in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Halverson, Mark A.; Shui, Bin; Evans, Meredydd

    2009-04-30

    This report is part of a series of reports on building energy efficiency codes in countries associated with the Asian Pacific Partnership (APP) - Australia, South Korea, Japan, China, India, and the United States of America (U.S.). This reports gives an overview of the development of building energy codes in U.S., including national energy policies related to building energy codes, history of building energy codes, recent national projects and activities to promote building energy codes. The report also provides a review of current building energy codes (such as building envelope, HVAC, lighting, and water heating) for commercial and residential buildings in the U.S.

  19. Energy problems of the United States

    International Nuclear Information System (INIS)

    Pertuzio, A.

    2006-01-01

    The united states are the third world producer of oil which accounts for 440% of world production and 20 million barrels/day of which 60% are imported. That dependence on imports is likely to increase in the next decades. Such supplies and their security are therefore a fundamental factor of the United States foreign policy in combination with their political, economic and strategic objectives in a world both unsure and dangerous

  20. ENERGY-DEPENDENT POWER SPECTRAL STATES AND ORIGIN OF APERIODIC VARIABILITY IN BLACK HOLE BINARIES

    International Nuclear Information System (INIS)

    Yu Wenfei; Zhang Wenda

    2013-01-01

    We found that the black hole candidate MAXI J1659–152 showed distinct power spectra, i.e., power-law noise (PLN) versus band-limited noise (BLN) plus quasi-periodic oscillations (QPOs) below and above about 2 keV, respectively, in observations with Swift and the Rossi X-ray Timing Explorer during the 2010 outburst, indicating a high energy cutoff of the PLN and a low energy cutoff of the BLN and QPOs around 2 keV. The emergence of the PLN and the fading of the BLN and QPOs initially took place below 2 keV when the source entered the hard intermediate state and settled in the soft state three weeks later. The evolution was accompanied by the emergence of the disk spectral component and decreases in the amplitudes of variability in the soft and hard X-ray bands. Our results indicate that the PLN is associated with an optically thick disk in both hard and intermediate states, and the power spectral state is independent of the X-ray energy spectral state in a broadband view. We suggest that in the hard or intermediate state, the BLN and QPOs emerge from the innermost hot flow subjected to Comptonization, while the PLN originates from the optically thick disk farther out. The energy cutoffs of the PLN and the BLN or QPOs then follow the temperature of the seed photons from the inner edge of the optically thick disk, while the high frequency cutoff of the PLN follows the orbital frequency of the inner edge of the optically thick disk as well.

  1. The state of development of wave energy

    International Nuclear Information System (INIS)

    Duckers, L.J.

    1991-01-01

    Wave energy converters are being developed and tested in as many as ten countries. The author believes that the shore mounted converters will be economically attractive in many locations around the world. These devices are simple and easily maintained. In order to harvest the greater offshore resource floating devices such as the Clam, Duck and Whale will be needed. Urgent research and development is needed to bring these to the prototype stage. Future deployment of large arrays of these floating systems could be quickly and easily achieved in many parts of the world and they would provide considerable quantities of environmentally benign, reasonably cheap energy. (author) 6 figs., 5 refs

  2. 2016 Offshore Wind Energy Resource Assessment for the United States

    Energy Technology Data Exchange (ETDEWEB)

    Musial, Walt [National Renewable Energy Lab. (NREL), Golden, CO (United States); Heimiller, Donna [National Renewable Energy Lab. (NREL), Golden, CO (United States); Beiter, Philipp [National Renewable Energy Lab. (NREL), Golden, CO (United States); Scott, George [National Renewable Energy Lab. (NREL), Golden, CO (United States); Draxl, Caroline [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    This report, the 2016 Offshore Wind Energy Resource Assessment for the United States, was developed by the National Renewable Energy Laboratory, and updates a previous national resource assessment study, and refines and reaffirms that the available wind resource is sufficient for offshore wind to be a large-scale contributor to the nation's electric energy supply.

  3. Energy balance of the Parana State - 1980-1994

    International Nuclear Information System (INIS)

    1995-01-01

    This document presents the energetic balance of Parana State - 1980/1994, including the energy fluxes from primary and secondary energy sources in the main sectors of Parana economy. It informs consumption, production and energy external dependence. 26 figs., 88 tabs

  4. Energy balance from Parana State - 1980-1992

    International Nuclear Information System (INIS)

    1993-01-01

    The energy flows of primary and secondary energy sources since the production to the end consumption in the main sectors of Parana State economy during 1980 to 1992, are presented. The supply and demand, consumption and production of energy sources are shown. Some information about resources and reserves are also cited. (C.G.C.)

  5. Energy balance of the Sao Paulo State - 1991

    International Nuclear Information System (INIS)

    1993-01-01

    The energy production and consumption for the several categories of the economy in the Brazilian State of Sao Paulo are presented. The data are given according to the energy source and to consumer sectors and information about the import, export, losses in the transformation and distribution of the several forms of energy is supplied. 18 figs., 120 tabs

  6. Composition-tuned band gap energy and refractive index in GaS{sub x}Se{sub 1−x} layered mixed crystals

    Energy Technology Data Exchange (ETDEWEB)

    Isik, Mehmet, E-mail: mehmet.isik@atilim.edu.tr [Department of Electrical and Electronics Engineering, Atilim University, 06836, Ankara (Turkey); Gasanly, Nizami [Department of Physics, Middle East Technical University, 06800, Ankara (Turkey); Virtual International Scientific Research Centre, Baku State University, 1148, Baku (Azerbaijan)

    2017-04-01

    Transmission and reflection measurements on GaS{sub x}Se{sub 1−x} mixed crystals (0 ≤ x ≤ 1) were carried out in the 400–1000 nm spectral range. Band gap energies of the studied crystals were obtained using the derivative spectra of transmittance and reflectance. The compositional dependence of band gap energy revealed that as sulfur (selenium) composition is increased (decreased) in the mixed crystals, band gap energy increases quadratically from 1.99 eV (GaSe) to 2.55 eV (GaS). Spectral dependencies of refractive indices of the mixed crystals were plotted using the reflectance spectra. It was observed that refractive index decreases nearly in a linear behavior with increasing band gap energy for GaS{sub x}Se{sub 1−x} mixed crystals. Moreover, the composition ratio of the mixed crystals was obtained from the energy dispersive spectroscopy measurements. The atomic compositions of the studied crystals are well-matched with composition x increasing from 0 to 1 by intervals of 0.25. - Highlights: • Transmission and reflection experiments were performed on GaS{sub x}Se{sub 1−x} mixed crystals. • Derivative spectra of transmittance and reflectance were used for analyses. • Compositional dependence of band gap energy and refractive index were reported.

  7. On the Effective Equation of State of Dark Energy

    DEFF Research Database (Denmark)

    Sloth, Martin Snoager

    2010-01-01

    In an effective field theory model with an ultraviolet momentum cutoff, there is a relation between the effective equation of state of dark energy and the ultraviolet cutoff scale. It implies that a measure of the equation of state of dark energy different from minus one, does not rule out vacuum...... energy as dark energy. It also indicates an interesting possibility that precise measurements of the infrared properties of dark energy can be used to probe the ultraviolet cutoff scale of effective quantum field theory coupled to gravity. In a toy model with a vacuum energy dominated universe...... with a Planck scale cutoff, the dark energy effective equation of state is -0.96....

  8. The ground state energy of a classical gas

    International Nuclear Information System (INIS)

    Conlon, J.G.

    1983-01-01

    The ground state energy of a classical gas is treated using a probability function for the position of the particles and a potential function. The lower boundary for the energy when the particle number is large is defined as ground state energy. The coulomb gas consisting of positive and negative particles is also treated (fixed and variable density case) the stability of the relativistic system is investigated as well. (H.B.)

  9. Energy gap of extended states in SiC-doped graphene nanoribbon: Ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoshi; Wu, Yong [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Shanghai Key Lab of Modern Optical System, Shanghai 200093 (China); Li, Zhongyao, E-mail: lizyusst@gmail.com [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Shanghai Key Lab of Modern Optical System, Shanghai 200093 (China); Gao, Yong [School of Science, Shanghai Second Polytechnic University, Shanghai 201209 (China)

    2017-04-01

    Highlights: • The gap of isolated ribbon is inversely proportional to the width of ribbon. • The gap of doped ribbon cannot be modeled by effective width approximation. • The fitted energy gap can match the experimental observations. • The doping results in a spin-polarized metallic-like band structure. - Abstract: The energy gap of extended states in zigzag graphene nanoribbons (ZGNRs) was examined on the basis of density-functional theory. In isolated ZGNRs, the energy gap is inversely proportional to the width of ribbon. It agrees well with the results from the Dirac equation in spin-unpolarized ZGNRs, although the considered ZGNRs have spin-polarized edges. However, the energy gap in SiC-doped ZGNRs cannot be modeled by effective width approximation. The doping also lifts the spin-degenerate of edge states and results in a metallic-like band structure near the Fermi level in SiC-doped ZGNRs. Our calculations may be helpful for understanding the origin of the reported single-channel ballistic transport in epitaxial graphene nanoribbons.

  10. State and Local Initiatives: Your Bridge to Renewable Energy and Energy Efficiency Resources (Brochure)

    International Nuclear Information System (INIS)

    Epstein, K.

    2001-01-01

    A brochure for local and state policymakers, informing them about the State and Local Initiatives team at the National Renewable Energy Laboratory. The brochure outlines the benefits of using renewables and energy efficiency, the benefits of using the State and Local Initiatives team as a liaison to the wealth of information at NREL, and some of the services and resources available

  11. 76 FR 54747 - State Energy Advisory Board

    Science.gov (United States)

    2011-09-02

    ... Committee Act (Pub. L. 92- 463; 86 Stat. 770) requires that public notice of these meetings be announced in... Energy Efficiency Programs Improvement Act of 1990 (Pub. L. 101-440). Tentative Agenda: Receive updates... National Laboratory (ORNL) to discuss new initiatives and technologies and explore possible technology...

  12. State of the States 2009. Renewable Energy Development and the Role of Policy

    Energy Technology Data Exchange (ETDEWEB)

    Doris, Elizabeth [National Renewable Energy Lab. (NREL), Golden, CO (United States); McLaren, Joyce [National Renewable Energy Lab. (NREL), Golden, CO (United States); Healey, Victoria [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hockett, Stephen [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2009-10-01

    This report tracks the progress of U.S. renewable energy development at the state level, with metrics on development status and reviews of relevant policies. The analysis offers state-by-state policy suggestions and develops performance-based evaluation metrics to accelerate and improve renewable energy development.

  13. From Particles in Steady State Shear Bands via Micro-Macro to Macroscopic Rheology Laws

    NARCIS (Netherlands)

    Luding, S.; Singh, A.; Roy, S.; Vescovi, D.; Weinhart, T.; Magnanimo, V.; Li, Xikui; Feng, Yuntian; Mustoe, Graham

    2017-01-01

    Particulate systems and granular matter are discrete systems made of many particles; they display interesting dynamic or static, fluid- or solid-like states, respectively, or both together. The challenge of bridging the gap between the particulate, microscopic picture towards their continuum

  14. C-band solid state dual polarization T/R modules for airborne SAR systems

    NARCIS (Netherlands)

    Vermeulen, B.C.B.; Koomen, P.J.; Hoogeboom, P.; Snoeij, P.; Pouwels, H.

    1996-01-01

    The use of distributed power in a, on a phased array antenna based, SAR system offers new possibilities for the system operation. As a preparation for future spaceborne SAR systems using solid state transmitters with electronically steerable phased array antenna, the PHARUS system has been

  15. Ground state energy fluctuations in the nuclear shell model

    International Nuclear Information System (INIS)

    Velazquez, Victor; Hirsch, Jorge G.; Frank, Alejandro; Barea, Jose; Zuker, Andres P.

    2005-01-01

    Statistical fluctuations of the nuclear ground state energies are estimated using shell model calculations in which particles in the valence shells interact through well-defined forces, and are coupled to an upper shell governed by random 2-body interactions. Induced ground-state energy fluctuations are found to be one order of magnitude smaller than those previously associated with chaotic components, in close agreement with independent perturbative estimates based on the spreading widths of excited states

  16. On calculations of the ground state energy in quantum mechanics

    International Nuclear Information System (INIS)

    Efimov, G.V.

    1991-02-01

    In nonrelativistic quantum mechanics the Wick-ordering method called the oscillator representation suggested to calculate the ground-state energy for a wide class of potentials allowing the existence of a bound state. The following examples are considered: the orbital excitations of the ground-state in the Coulomb plus linear potential, the Schroedinger equation with a ''relativistic'' kinetic energy √p 2 +m 2 , the Coulomb three-body problem. (author). 22 refs, 2 tabs

  17. Computational Design of Flat-Band Material

    Science.gov (United States)

    Hase, I.; Yanagisawa, T.; Kawashima, K.

    2018-02-01

    Quantum mechanics states that hopping integral between local orbitals makes the energy band dispersive. However, in some special cases, there are bands with no dispersion due to quantum interference. These bands are called as flat band. Many models having flat band have been proposed, and many interesting physical properties are predicted. However, no real compound having flat band has been found yet despite the 25 years of vigorous researches. We have found that some pyrochlore oxides have quasi-flat band just below the Fermi level by first principles calculation. Moreover, their valence bands are well described by a tight-binding model of pyrochlore lattice with isotropic nearest neighbor hopping integral. This model belongs to a class of Mielke model, whose ground state is known to be ferromagnetic with appropriate carrier doping and on-site repulsive Coulomb interaction. We have also performed a spin-polarized band calculation for the hole-doped system from first principles and found that the ground state is ferromagnetic for some doping region. Interestingly, these compounds do not include magnetic element, such as transition metal and rare-earth elements.

  18. Feasibility of producing a short, high energy s-band linear accelerator using a klystron power source.

    Science.gov (United States)

    Baillie, Devin; St Aubin, J; Fallone, B G; Steciw, S

    2013-04-01

    To use a finite-element method (FEM) model to study the feasibility of producing a short s-band (2.9985 GHz) waveguide capable of producing x-rays energies up to 10 MV, for applications in a linac-MR, as well as conventional radiotherapy. An existing waveguide FEM model developed by the authors' group is used to simulate replacing the magnetron power source with a klystron. Peak fields within the waveguide are compared with a published experimental threshold for electric breakdown. The RF fields in the first accelerating cavity are scaled, approximating the effect of modifications to the first coupling cavity. Electron trajectories are calculated within the RF fields, and the energy spectrum, beam current, and focal spot of the electron beam are analyzed. One electron spectrum is selected for Monte Carlo simulations and the resulting PDD compared to measurement. When the first cavity fields are scaled by a factor of 0.475, the peak magnitude of the electric fields within the waveguide are calculated to be 223.1 MV∕m, 29% lower than the published threshold for breakdown at this operating frequency. Maximum electron energy increased from 6.2 to 10.4 MeV, and beam current increased from 134 to 170 mA. The focal spot FWHM is decreased slightly from 0.07 to 0.05 mm, and the width of the energy spectrum increased slightly from 0.44 to 0.70 MeV. Monte Carlo results show dmax is at 2.15 cm for a 10 × 10 cm(2) field, compared with 2.3 cm for a Varian 10 MV linac, while the penumbral widths are 4.8 and 5.6 mm, respectively. The authors' simulation results show that a short, high-energy, s-band accelerator is feasible and electric breakdown is not expected to interfere with operation at these field strengths. With minor modifications to the first coupling cavity, all electron beam parameters are improved.

  19. Feasibility of producing a short, high energy s-band linear accelerator using a klystron power source

    Energy Technology Data Exchange (ETDEWEB)

    Baillie, Devin [Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Aubin, J. St. [Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Fallone, B. G. [Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Steciw, S. [Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2013-04-15

    Purpose: To use a finite-element method (FEM) model to study the feasibility of producing a short s-band (2.9985 GHz) waveguide capable of producing x-rays energies up to 10 MV, for applications in a linac-MR, as well as conventional radiotherapy. Methods: An existing waveguide FEM model developed by the authors' group is used to simulate replacing the magnetron power source with a klystron. Peak fields within the waveguide are compared with a published experimental threshold for electric breakdown. The RF fields in the first accelerating cavity are scaled, approximating the effect of modifications to the first coupling cavity. Electron trajectories are calculated within the RF fields, and the energy spectrum, beam current, and focal spot of the electron beam are analyzed. One electron spectrum is selected for Monte Carlo simulations and the resulting PDD compared to measurement. Results: When the first cavity fields are scaled by a factor of 0.475, the peak magnitude of the electric fields within the waveguide are calculated to be 223.1 MV/m, 29% lower than the published threshold for breakdown at this operating frequency. Maximum electron energy increased from 6.2 to 10.4 MeV, and beam current increased from 134 to 170 mA. The focal spot FWHM is decreased slightly from 0.07 to 0.05 mm, and the width of the energy spectrum increased slightly from 0.44 to 0.70 MeV. Monte Carlo results show d{sub max} is at 2.15 cm for a 10 Multiplication-Sign 10 cm{sup 2} field, compared with 2.3 cm for a Varian 10 MV linac, while the penumbral widths are 4.8 and 5.6 mm, respectively. Conclusions: The authors' simulation results show that a short, high-energy, s-band accelerator is feasible and electric breakdown is not expected to interfere with operation at these field strengths. With minor modifications to the first coupling cavity, all electron beam parameters are improved.

  20. Feasibility of producing a short, high energy s-band linear accelerator using a klystron power source

    International Nuclear Information System (INIS)

    Baillie, Devin; Aubin, J. St.; Fallone, B. G.; Steciw, S.

    2013-01-01

    Purpose: To use a finite-element method (FEM) model to study the feasibility of producing a short s-band (2.9985 GHz) waveguide capable of producing x-rays energies up to 10 MV, for applications in a linac-MR, as well as conventional radiotherapy. Methods: An existing waveguide FEM model developed by the authors' group is used to simulate replacing the magnetron power source with a klystron. Peak fields within the waveguide are compared with a published experimental threshold for electric breakdown. The RF fields in the first accelerating cavity are scaled, approximating the effect of modifications to the first coupling cavity. Electron trajectories are calculated within the RF fields, and the energy spectrum, beam current, and focal spot of the electron beam are analyzed. One electron spectrum is selected for Monte Carlo simulations and the resulting PDD compared to measurement. Results: When the first cavity fields are scaled by a factor of 0.475, the peak magnitude of the electric fields within the waveguide are calculated to be 223.1 MV/m, 29% lower than the published threshold for breakdown at this operating frequency. Maximum electron energy increased from 6.2 to 10.4 MeV, and beam current increased from 134 to 170 mA. The focal spot FWHM is decreased slightly from 0.07 to 0.05 mm, and the width of the energy spectrum increased slightly from 0.44 to 0.70 MeV. Monte Carlo results show d max is at 2.15 cm for a 10 × 10 cm 2 field, compared with 2.3 cm for a Varian 10 MV linac, while the penumbral widths are 4.8 and 5.6 mm, respectively. Conclusions: The authors' simulation results show that a short, high-energy, s-band accelerator is feasible and electric breakdown is not expected to interfere with operation at these field strengths. With minor modifications to the first coupling cavity, all electron beam parameters are improved.

  1. Pressure-induced emission band separation of the hybridized local and charge transfer excited state in a TPE-based crystal.

    Science.gov (United States)

    Liu, Xuedan; Li, Aisen; Xu, Weiqing; Ma, Zhiyong; Jia, Xinru

    2018-05-08

    We herein report a newly synthesized simple molecule, named TPE[double bond, length as m-dash]C4, with twisted D-A structure. TPE[double bond, length as m-dash]C4 showed two intrinsic emission bands ascribed to the locally excited (LE) state and the intramolecular charge transfer (ICT) state, respectively. In the crystal state, the LE emission band is usually observed. However, by applying hydrostatic pressure to the powder sample and the single crystal sample of TPE[double bond, length as m-dash]C4, dual-fluorescence (445 nm and 532 nm) was emerged under high pressure, owing to the pressure-induced emission band separation of the hybridized local and charge transfer excited state (HLCT). It is found that the emission of TPE[double bond, length as m-dash]C4 is generally determined by the ratio of the LE state to the ICT state. The ICT emission band is much more sensitive to the external pressure than the LE emission band. The HLCT state leads to a sample with different responsiveness to grinding and hydrostatic pressure. This study is of significance in the molecular design of such D-A type molecules and in the control of photoluminescence features by molecular structure. Such results are expected to pave a new way to further understand the relationship between the D-A molecular structure and stimuli-responsive properties.

  2. The design study of the high power solid-state amplifier in S-band

    International Nuclear Information System (INIS)

    Tozyo, E.; Kobayashi, K.; Yoshida, K.

    1976-01-01

    We have designed the 500W high power solid-state amplifier for the microwave system of INS electron linac. In this design study the output pulse power level of each module is set as possible as high, so the total number of elements is well reduced within the present microwave technics. In comparison with TWTA highly stabilized and maintenance-free operations are expected with 5 years' MTF. (auth.)

  3. Resting-state theta band connectivity and graph analysis in generalized social anxiety disorder

    Directory of Open Access Journals (Sweden)

    Mengqi Xing

    2017-01-01

    Conclusions: Theta-dependent interconnectivity was associated with state anxiety in gSAD and an increase in information processing efficiency in gSAD (compared to controls. Results may represent enhanced baseline self-focused attention, which is consistent with cognitive models of gSAD and fMRI studies implicating emotion dysregulation and disturbances in task negative networks (e.g., default mode network in gSAD.

  4. Photovoltaic solar energy: State of the art

    International Nuclear Information System (INIS)

    Van Sark, W.G.J.H.M.; Sinke, W.C.

    1993-03-01

    Attention is paid to developments in the Netherlands of all aspects of photovoltaic (PV) energy: solar cells, components, PV-systems and all kinds of applications. Efficiencies of the present solar cell types still increase, varying from more than 10% for organic/TiO 2 solar cells to 33% for GaAs/GaSb concentrator tandem solar cells. 3 figs., 2 ills., 1 tab

  5. Insight on the energy in the United States

    International Nuclear Information System (INIS)

    Jamet, Ph.

    2006-11-01

    This document recapitulates the main characteristics and the key data of the energy in the United States (fossil energies, renewable energies, electric power production). The main american strategies are then described as the actions at the international scale during the last five years. The main data of the research programs in the energy domain are presented and the possible consequences of the government change at the Congress are analyzed. (A.L.B.)

  6. Metamorphosis of strain/stress on optical band gap energy of ZAO thin films via manipulation of thermal annealing process

    International Nuclear Information System (INIS)

    Malek, M.F.; Mamat, M.H.; Musa, M.Z.; Soga, T.; Rahman, S.A.; Alrokayan, Salman A.H.; Khan, Haseeb A.; Rusop, M.

    2015-01-01

    We report on the growth of Al-doped ZnO (ZAO) thin films prepared by the sol–gel technique associated with dip-coating onto Corning 7740 glass substrates. The influence of varying thermal annealing (T a ) temperature on crystallisation behaviour, optical and electrical properties of ZAO films has been systematically investigated. All films are polycrystalline with a hexagonal wurtzite structure with a preferential orientation according to the direction 〈0 0 2〉. The metamorphosis of strain/stress effects in ZAO thin films has been investigated using X-ray diffraction. The as growth films have a large compressive stress of 0.55 GPa, which relaxed to 0.25 GPa as the T a was increased to 500 °C. Optical parameters such as optical transmittance, absorption coefficient, refractive index and optical band gap energy have been studied and discussed with respect to T a . All films exhibit a transmittance above 80–90% along the visible–NIR range up to 1500 nm and a sharp absorption onset below 400 nm corresponding to the fundamental absorption edge of ZnO. Experimental results show that the tensile stress in the films reveals an incline pattern with the optical band gap energy, while the compressive stress shows opposite relation. - Highlights: • Minimum stress of highly c-axis oriented ZAO was grown at suitable T a temperature. • The ZAO crystal orientation was influenced by strain/stress of the film. • Minimum stress/strain of ZAO film leads to lower defects. • Bandgap and defects were closely intertwined with strain/stress. • We report additional optical and electrical properties based on T a temperature

  7. Metamorphosis of strain/stress on optical band gap energy of ZAO thin films via manipulation of thermal annealing process

    Energy Technology Data Exchange (ETDEWEB)

    Malek, M.F., E-mail: firz_solarzelle@yahoo.com [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA UiTM, 40450 Shah Alam, Selangor (Malaysia); Mamat, M.H. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Musa, M.Z. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM) Pulau Pinang, Jalan Permatang Pauh, 13500 Permatang Pauh, Pulau Pinang (Malaysia); Soga, T. [Department of Frontier Materials, Nagoya Institute of Technology (NITech), Nagoya 466-8555 (Japan); Rahman, S.A. [Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, Universiti Malaya (UM), 50603 Kuala Lumpur (Malaysia); Alrokayan, Salman A.H.; Khan, Haseeb A. [Department of Biochemistry, College of Science, King Saud University (KSU), Riyadh 11451 (Saudi Arabia); Rusop, M. [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA UiTM, 40450 Shah Alam, Selangor (Malaysia)

    2015-04-15

    We report on the growth of Al-doped ZnO (ZAO) thin films prepared by the sol–gel technique associated with dip-coating onto Corning 7740 glass substrates. The influence of varying thermal annealing (T{sub a}) temperature on crystallisation behaviour, optical and electrical properties of ZAO films has been systematically investigated. All films are polycrystalline with a hexagonal wurtzite structure with a preferential orientation according to the direction 〈0 0 2〉. The metamorphosis of strain/stress effects in ZAO thin films has been investigated using X-ray diffraction. The as growth films have a large compressive stress of 0.55 GPa, which relaxed to 0.25 GPa as the T{sub a} was increased to 500 °C. Optical parameters such as optical transmittance, absorption coefficient, refractive index and optical band gap energy have been studied and discussed with respect to T{sub a}. All films exhibit a transmittance above 80–90% along the visible–NIR range up to 1500 nm and a sharp absorption onset below 400 nm corresponding to the fundamental absorption edge of ZnO. Experimental results show that the tensile stress in the films reveals an incline pattern with the optical band gap energy, while the compressive stress shows opposite relation. - Highlights: • Minimum stress of highly c-axis oriented ZAO was grown at suitable T{sub a} temperature. • The ZAO crystal orientation was influenced by strain/stress of the film. • Minimum stress/strain of ZAO film leads to lower defects. • Bandgap and defects were closely intertwined with strain/stress. • We report additional optical and electrical properties based on T{sub a} temperature.

  8. Weak wide-band signal detection method based on small-scale periodic state of Duffing oscillator

    Science.gov (United States)

    Hou, Jian; Yan, Xiao-peng; Li, Ping; Hao, Xin-hong

    2018-03-01

    The conventional Duffing oscillator weak signal detection method, which is based on a strong reference signal, has inherent deficiencies. To address these issues, the characteristics of the Duffing oscillatorʼs phase trajectory in a small-scale periodic state are analyzed by introducing the theory of stopping oscillation system. Based on this approach, a novel Duffing oscillator weak wide-band signal detection method is proposed. In this novel method, the reference signal is discarded, and the to-be-detected signal is directly used as a driving force. By calculating the cosine function of a phase space angle, a single Duffing oscillator can be used for weak wide-band signal detection instead of an array of uncoupled Duffing oscillators. Simulation results indicate that, compared with the conventional Duffing oscillator detection method, this approach performs better in frequency detection intervals, and reduces the signal-to-noise ratio detection threshold, while improving the real-time performance of the system. Project supported by the National Natural Science Foundation of China (Grant No. 61673066).

  9. Design study of an S-band RF cavity of a dual-energy electron LINAC for the CIS

    Science.gov (United States)

    Lee, Byeong-No; Park, Hyungdal; Song, Ki-baek; Li, Yonggui; Lee, Byung Cheol; Cha, Sung-su; Lee, Jong-Chul; Shin, Seung-Wook; Chai, Jong-seo

    2014-01-01

    The design of a resonance frequency (RF) cavity for the dual-energy S-band electron linear accelerator (LINAC) has been carried out for the cargo inspection system (CIS). This Standing-wave-type RF cavity is operated at a frequency under the 2856-MHz resonance frequency and generates electron beams of 9 MeV (high mode) and 6 MeV (low mode). The electrons are accelerated from the initial energy of the electron gun to the target energy (9 or 6 MeV) inside the RF cavity by using the RF power transmitted from a 5.5-MW-class klystron. Then, electron beams with a 1-kW average power (both high mode and low mode) bombard an X-ray target a 2-mm spot size. The proposed accelerating gradient was 13 MV/m, and the designed Q value was about 7100. On going research on 15-MeV non-destructive inspections for military or other applications is presented.

  10. High spin rotational bands in Zn

    Indian Academy of Sciences (India)

    We present here some preliminary results from our studies in the. ~ ¼ region in which we have observed an yrast band structure in Zn extending to spin (41/2 ). ... gaps implies that nuclei may exhibit different shapes at different excitation energies. .... uration, identifying previously unobserved states up to an excitation energy ...

  11. A detailed analysis of the energy levels configuration existing in the band gap of supersaturated silicon with titanium for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, E.; Dueñas, S.; Castán, H.; García, H.; Bailón, L. [Dept. de Electricidad y Electrónica, Universidad de Valladolid, Paseo de Belén 15, 47011 Valladolid (Spain); Montero, D.; García-Hernansanz, R.; García-Hemme, E.; González-Díaz, G. [Dept. de Física Aplicada III (Electricidad y Electrónica), Univ. Complutense de Madrid, 28040 Madrid (Spain); CEI Campus Moncloa, UCM-UPM, 28040 Madrid (Spain); Olea, J. [CEI Campus Moncloa, UCM-UPM, 28040 Madrid (Spain); Instituto de Energía Solar, E.T.S.I. de Telecomunicación, Univ. Politécnica de Madrid, 28040 Madrid (Spain)

    2015-12-28

    The energy levels created in supersaturated n-type silicon substrates with titanium implantation in the attempt to create an intermediate band in their band-gap are studied in detail. Two titanium ion implantation doses (10{sup 13 }cm{sup -2} and 10{sup 14 }cm{sup -2}) are studied in this work by conductance transient technique and admittance spectroscopy. Conductance transients have been measured at temperatures of around 100 K. The particular shape of these transients is due to the formation of energy barriers in the conduction band, as a consequence of the band-gap narrowing induced by the high titanium concentration. Moreover, stationary admittance spectroscopy results suggest the existence of different energy level configuration, depending on the local titanium concentration. A continuum energy level band is formed when titanium concentration is over the Mott limit. On the other hand, when titanium concentration is lower than the Mott limit, but much higher than the donor impurity density, a quasi-continuum energy level distribution appears. Finally, a single deep center appears for low titanium concentration. At the n-type substrate, the experimental results obtained by means of thermal admittance spectroscopy at high reverse bias reveal the presence of single levels located at around E{sub c}-425 and E{sub c}-275 meV for implantation doses of 10{sup 13 }cm{sup −2} and 10{sup 14 }cm{sup −2}, respectively. At low reverse bias voltage, quasi-continuously distributed energy levels between the minimum of the conduction bands, E{sub c} and E{sub c}-450 meV, are obtained for both doses. Conductance transients detected at low temperatures reveal that the high impurity concentration induces a band gap narrowing which leads to the formation of a barrier in the conduction band. Besides, the relationship between the activation energy and the capture cross section values of all the energy levels fits very well to the Meyer-Neldel rule. As it is known

  12. A chain-of-states acceleration method for the efficient location of minimum energy paths

    International Nuclear Information System (INIS)

    Hernández, E. R.; Herrero, C. P.; Soler, J. M.

    2015-01-01

    We describe a robust and efficient chain-of-states method for computing Minimum Energy Paths (MEPs) associated to barrier-crossing events in poly-atomic systems, which we call the acceleration method. The path is parametrized in terms of a continuous variable t ∈ [0, 1] that plays the role of time. In contrast to previous chain-of-states algorithms such as the nudged elastic band or string methods, where the positions of the states in the chain are taken as variational parameters in the search for the MEP, our strategy is to formulate the problem in terms of the second derivatives of the coordinates with respect to t, i.e., the state accelerations. We show this to result in a very simple and efficient method for determining the MEP. We describe the application of the method to a series of test cases, including two low-dimensional problems and the Stone-Wales transformation in C 60

  13. An Evaluation of State Energy Program Accomplishments: 2002 Program Year

    Energy Technology Data Exchange (ETDEWEB)

    Schweitzer, M.

    2005-07-13

    The U.S. Department of Energy's (DOE's) State Energy Program (SEP) was established in 1996 by merging the State Energy Conservation Program (SECP) and the Institutional Conservation Program (ICP), both of which had been in existence since 1976 (U.S. DOE 2001a). The SEP provides financial and technical assistance for a wide variety of energy efficiency and renewable energy activities undertaken by the states and territories. SEP provides money to each state and territory according to a formula that accounts for population and energy use. In addition to these ''Formula Grants'', SEP ''Special Project'' funds are made available on a competitive basis to carry out specific types of energy efficiency and renewable energy activities (U.S. DOE 2003c). The resources provided by DOE typically are augmented by money and in-kind assistance from a number of sources, including other federal agencies, state and local governments, and the private sector. The states SEP efforts include several mandatory activities, such as establishing lighting efficiency standards for public buildings, promoting car and vanpools and public transportation, and establishing policies for energy-efficient government procurement practices. The states and territories also engage in a broad range of optional activities, including holding workshops and training sessions on a variety of topics related to energy efficiency and renewable energy, providing energy audits and building retrofit services, offering technical assistance, supporting loan and grant programs, and encouraging the adoption of alternative energy technologies. The scope and variety of activities undertaken by the various states and territories is extremely broad, and this reflects the diversity of conditions and needs found across the country and the efforts of participating states and territories to respond to them. The purpose of this report is to present estimates of the energy and

  14. ENERGY USE ANALYSIS FOR RICE PRODUCTION IN NASARAWA STATE, NIGERIA

    Directory of Open Access Journals (Sweden)

    Hussaini Yusuf Ibrahim

    2012-12-01

    Full Text Available The study was conducted to analyze energy use for in rice production in Nasarawa state Nigeria using a sample of 120 randomly selected rice farmers. Energy productivity, energy efficiency and specific energy were computed and simple descriptive statistics was used for data analysis. The energy use pattern shows that, rice production consumed an average total energy of 12906.8 MJha-1, with herbicide energy input contributing the largest share (53.55 %. Human labour had the least share (0.74 % of the total energy input used. The energy productivity, Specific energy and energy efficiency were 0.3 MJ-1, 3.6 MJ-1 and 4.1 respectively. A total of 10925.0 MJ of energy was used in the form of indirect energy and 1981.8MJ was in the direct form of energy. Non-renewable energy forms contributed the largest share (80.63 % of the total energy input used for rice production in the study area. Rice production in the study area was observed to be mainly dependent on non-renewable and indirect energy input especially herbicide. Thus, the study recommends the introduction of integrated weed management system in order to reduce cost and dependence on a non-renewable input for weed control.

  15. The Energy Budget of Steady State Photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Dr. David M. Kramer

    2012-11-27

    Progress is reported in addressing these questions: Why do hcef mutants have increased CEF1? Is increased CEF1 caused by elevated expression or altered regulation of CEF1 components? Which metabolic pools can be regulators of CEF1? Do metabolites influence CEF1 directly or indirectly? Which CEF1 pathways are activated in high CEF1 mutants? Is PQR a proton pump? Is elevated CEF1 activated by state transitions?

  16. K- nuclear states: Binding energies and widths

    Czech Academy of Sciences Publication Activity Database

    Hrtánková, Jaroslava; Mareš, Jiří

    2017-01-01

    Roč. 96, č. 1 (2017), č. článku 015205. ISSN 2469-9985 R&D Projects: GA ČR(CZ) GA15-04301S Institutional support: RVO:61389005 Keywords : K- nuclear * kaonic * states Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 3.820, year: 2016

  17. United States Energy Policy: Security Not Independence

    Science.gov (United States)

    2013-03-01

    on leased land, ensuring fracking is done responsibly, and getting more natural gas and hybrid systems into U.S. mass transit. Internationally, the...fewer environ disturbances -Can store underground -Environ impacts of fracking unknown -uses large amount of water -potential for saline...from shale continues to rise as the United States determines how to drill safely. However, the impact of fracking on the environment is still

  18. Building Stronger State Energy Partnerships with the U.S. Department of Energy

    Energy Technology Data Exchange (ETDEWEB)

    Marks, Kate

    2011-09-30

    This final technical report details the results of total work efforts and progress made from October 2007 – September 2011 under the National Association of State Energy Officials (NASEO) cooperative agreement DE-FC26-07NT43264, Building Stronger State Energy Partnerships with the U.S. Department of Energy. Major topical project areas in this final report include work efforts in the following areas: Energy Assurance and Critical Infrastructure, State and Regional Technical Assistance, Regional Initiative, Regional Coordination and Technical Assistance, and International Activities in China. All required deliverables have been provided to the National Energy Technology Laboratory and DOE program officials.

  19. Prediction of energies of yrast band in some even-even nuclei

    International Nuclear Information System (INIS)

    Varshney, A.K.; Singh, Yuvraj; Gupta, D.K.; Singh, M.; Gupta, K.K.; Bihari, Chhail; Dhiman, S.K.

    2012-01-01

    The deformation parameter β and γ of the collective model of Bohr and Mottelson are basic descriptors of the nuclear equilibrium shape and structure. The researchers found that the values of γ obtained from energies (= γ e ) are nearly equal to the value of γ derived from transition rate (= γ b ) in even Xe, Ba and Ce nuclei (A∼120-140) and Hf, W, Os, Pt and Hg nuclei (A∼160-200) using rigid triaxial rotor model of Davydov-Filippov. In the present study, the relatively light mass nuclei (Mo, Ru and Pd) have been taken. As far as γ is concerned, it is known that the Ru chains of nuclei is intermediate between the two having opposite trends for parameter γ, decreasing for Mo and increasing for Pd, and has an irregular behaviour in itself with the increase of neutron number

  20. Energy balance from Bahia state 2013 - series 1996-2012

    International Nuclear Information System (INIS)

    2013-01-01

    This Energy Balance from Bahia, Brazil, presents six chapters, as follows: the chapter 1 approaches the profile of the energy system, showing the structure of the Bahia state energy matrix in the year of 2012, and the modifications occurred during the period of 1996-2012. Then the consolidated information are presented, from production to final consumption, for the set of primary and secondary sources, as well as comparative tables of states x national production of major energy production; the chapter 2 analyses the development, during the period of 1996-2012, in energy supply according to the Primary and Secondary sources; the chapter 3 comprised the evolution of energy consumption by sources and according the social-economic sectors; chapter 4 focus, within a broader view, the evolution of self-sufficiency energy state, confronting the production of primary energy to the total energy demand; in chapter 5 is given the status of the Energy Transformation Centers of the state, highlighting the balances of the Refinery Landulpho Alves (RLAM) and the Power Plants of Public Service and Self-Producer and the chapter 6 contains the consolidated matrixes expressed in the years of 1980, 1985 and 1990-2012

  1. Nanoscale probing of bandgap states on oxide particles using electron energy-loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qianlang [School for the Engineering of Matter, Transport and Energy, Arizona State University, 85287 AZ (United States); March, Katia [Laboratoire de Physique des Solides, Bâtiment 510, Université Paris-Sud, 91405 Orsay Cedex (France); Crozier, Peter A., E-mail: CROZIER@asu.edu [School for the Engineering of Matter, Transport and Energy, Arizona State University, 85287 AZ (United States)

    2017-07-15

    Surface and near-surface electronic states were probed with nanometer spatial resolution in MgO and TiO{sub 2} anatase nanoparticles using ultra-high energy resolution electron energy-loss spectroscopy (EELS) coupled to a scanning transmission electron microscope (STEM). This combination allows the surface electronic structure determined with spectroscopy to be correlated with nanoparticle size, morphology, facet etc. By acquiring the spectra in aloof beam mode, radiation damage to the surface can be significantly reduced while maintaining the nanometer spatial resolution. MgO and TiO{sub 2} showed very different bandgap features associated with the surface/sub-surface layer of the nanoparticles. Spectral simulations based on dielectric theory and density of states models showed that a plateau feature found in the pre-bandgap region in the spectra from (100) surfaces of 60 nm MgO nanocubes is consistent with a thin hydroxide surface layer. The spectroscopy shows that this hydroxide species gives rise to a broad filled surface state at 1.1 eV above the MgO valence band. At the surfaces of TiO{sub 2} nanoparticles, pronounced peaks were observed in the bandgap region, which could not be well fitted to defect states. In this case, the high refractive index and large particle size may make Cherenkov or guided light modes the likely causes of the peaks. - Highlights: • Bandgap states detected with aloof beam monochromated EELS on oxide nanoparticle surfaces. • Dielectric theory applied to simulate the spectra and interpret surface structure. • Density of states models also be employed to understand the surface electronic structure. • In MgO, one states associate with water species was found close to the valence band edge. • In anatase, two mid-gap states associated with point defects were found.

  2. A short course on topological insulators band structure and edge states in one and two dimensions

    CERN Document Server

    Asbóth, János K; Pályi, András

    2016-01-01

    This course-based primer provides newcomers to the field with a concise introduction to some of the core topics in the emerging field of topological insulators. The aim is to provide a basic understanding of edge states, bulk topological invariants, and of the bulk--boundary correspondence with as simple mathematical tools as possible. The present approach uses noninteracting lattice models of topological insulators, building gradually on these to arrive from the simplest one-dimensional case (the Su-Schrieffer-Heeger model for polyacetylene) to two-dimensional time-reversal invariant topological insulators (the Bernevig-Hughes-Zhang model for HgTe). In each case the discussion of simple toy models is followed by the formulation of the general arguments regarding topological insulators. The only prerequisite for the reader is a working knowledge in quantum mechanics, the relevant solid state physics background is provided as part of this self-contained text, which is complemented by end-of-chapter problems.

  3. CdS{sub x}Te{sub 1-x} ternary semiconductors band gaps calculation using ground state and GW approximations

    Energy Technology Data Exchange (ETDEWEB)

    Kheloufi, Nawal; Bouzid, Abderrazak, E-mail: a_bouzid34@hotmail.com

    2016-06-25

    We present band gap calculations of zinc-blende ternary CdS{sub x}Te{sub 1-x} semiconductors within the standard DFT and quasiparticle calculations employing pseudopotential method. The DFT, the local density approximation (LDA) and the Generalized Gradient Approximation (GGA) based calculations have given very poor results compared to experimental data. The quasiparticle calculations have been investigated via the one-shot GW approximation. The present paper discuses and confirms the effect of inclusion of the semicore states in the cadmium (Cd) pseudopotential. The obtained GW quasiparticle band gap using Cd{sup +20} pseudopotential has been improved compared to the obtained results from the available pseudopotential without the treatment of semicore states. Our DFT and quasiparticle band gap results are discussed and compared to the available theoretical calculations and experimental data. - Graphical abstract: Band gaps improvement concerning the binary and ternary alloys using the GW approximation and Cd{sup 20+} pseudopotential with others levels of approximations (the LDA and GGA approximation employing the Cd{sup 12+} and the LDA within Cd{sup 20+} pseudopotential). - Highlights: • The direct Γ- Γ and indirect Γ- X and Γ- L bands gaps show a nonlinear behavior when S content is enhanced. • The quasiparticle band gap result for the investigated semiconductors is improved using the GW approximation. • All CdS{sub x}Te{sub 1-x} compounds in all compositions range from 0 to 1 are direct band gap semiconductors.

  4. Training health and safety committees to use control banding: lessons learned and opportunities for the United States.

    Science.gov (United States)

    Bracker, Anne L; Morse, Timothy F; Simcox, Nancy J

    2009-05-01

    Control banding (CB) is a control-focused risk management model that has received international attention. CB strategies are designed to control workplace chemical exposures after the completion of a qualitative risk assessment. Connecticut was one of the first states to provide training on how to use this control-focused tool. Joint labor/management teams and individuals from 34 workplaces attended a control banding workshop and learned how to use one CB model, the United Kingdom (UK) Health and Safety Executive's Control of Substances Hazardous to Health (COSHH) Essentials Toolkit. After the initial training program the investigators used follow-up workshops, questionnaires, site visit data, and case studies to evaluate the training curriculum and assess the utility and effectiveness of this CB strategy. We found that the model is easily learned, although several areas for improvement were identified. Participants from 10 workplaces used COSHH Essentials to evaluate at least one task. The training curriculum was effective in that the agreement between the exposure variables coded by these workplaces and one of the workshop instructors, a certified industrial hygienist (CIH), were highly concordant. The training curriculum and the model promoted a discussion of risk between workers and managers and resulted in the implementation of improvements in the work environment. The model agreed with both the CIH's and the worksites' qualitative risk assessments 65% of the time, and likely over-controlled for 71% (5/7) of the cases of nonagreement. Feedback from workshop participants benefits the current dialogue on the implications of implementing CB in the United States.

  5. Chapter 16 - Predictive Analytics for Comprehensive Energy Systems State Estimation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingchen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yang, Rui [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hodge, Brian S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhang, Jie [University of Texas at Dallas; Weng, Yang [Arizona State University

    2017-12-01

    Energy sustainability is a subject of concern to many nations in the modern world. It is critical for electric power systems to diversify energy supply to include systems with different physical characteristics, such as wind energy, solar energy, electrochemical energy storage, thermal storage, bio-energy systems, geothermal, and ocean energy. Each system has its own range of control variables and targets. To be able to operate such a complex energy system, big-data analytics become critical to achieve the goal of predicting energy supplies and consumption patterns, assessing system operation conditions, and estimating system states - all providing situational awareness to power system operators. This chapter presents data analytics and machine learning-based approaches to enable predictive situational awareness of the power systems.

  6. ''Super-radiant'' states in intermediate energy nuclear physics

    International Nuclear Information System (INIS)

    Auerbach, N.

    1994-01-01

    A ''super-radiant'' state emerges when, under certain conditions, one or a few ''internal'' states acquire a large collective decay width due to the coupling to one or a few ''external'' decay channels. The rest of the internal states are ''stripped'' of their decay width and become long lived quasistationary states. The essentials of such mechanism and its possible role in intermediate energy nuclear physics are discussed in this work

  7. State density of valence-band tail and photoconductivity amorphous hydrogenated silicon

    International Nuclear Information System (INIS)

    Golikova, O.A.; Domashevskaya, Eh.P.; Mezdrogina, M.M.; Sorokina, K.L.; Terekhov, V.A.; Trostyanskij, S.N.

    1991-01-01

    Relation between photoconductivity and g(ε) mobility gap within the range adjoining to the top (mobility end) of valent zone (VZ tail) in a-Si:H film is studied. Stationary photoconductivity within spectral maximum range (χ=0.63μm) at Φ=10 17 photxcm -2 s -1 flow is measured. Density of g(ε) states are controlled using ultrasoft X-ray emission spectroscopy. It is shown, that correlation between photoconductivity and width of VZ tail may reflect the fact of their similar dependence o film heterogeneity: at the increase of share of microholes there occur both expansion of VZ tail and growth of number of respective hydrogen complexes and torn relations which results in drop of photoconductivity

  8. Transient and steady-state auditory gamma-band responses in first-degree relatives of people with autism spectrum disorder

    Directory of Open Access Journals (Sweden)

    Rojas Donald C

    2011-07-01

    Full Text Available Abstract Background Stimulus-related γ-band oscillations, which may be related to perceptual binding, are reduced in people with autism spectrum disorders (ASD. The purpose of this study was to examine auditory transient and steady-state γ-band findings in first-degree relatives of people with ASD to assess the potential familiality of these findings in ASD. Methods Magnetoencephalography (MEG recordings in 21 parents who had a child with an autism spectrum disorder (pASD and 20 healthy adult control subjects (HC were obtained. Gamma-band phase locking factor (PLF, and evoked and induced power to 32, 40 and 48 Hz amplitude-modulated sounds were measured for transient and steady-state responses. Participants were also tested on a number of behavioral and cognitive assessments related to the broad autism phenotype (BAP. Results Reliable group differences were seen primarily for steady-state responses. In the left hemisphere, pASD subjects exhibited lower phase-locked steady-state power in all three conditions. Total γ-band power, including the non-phase-locked component, was also reduced in the pASD group. In addition, pASD subjects had significantly lower PLF than the HC group. Correlations were seen between MEG measures and BAP measures. Conclusions The reduction in steady-state γ-band responses in the pASD group is consistent with previous results for children with ASD. Steady-state responses may be more sensitive than transient responses to phase-locking errors in ASD. Together with the lower PLF and phase-locked power in first-degree relatives, correlations between γ-band measures and behavioral measures relevant to the BAP highlight the potential of γ-band deficits as a potential new autism endophenotype.

  9. Multiscale energy reallocation during low-frequency steady-state brain response.

    Science.gov (United States)

    Wang, Yifeng; Chen, Wang; Ye, Liangkai; Biswal, Bharat B; Yang, Xuezhi; Zou, Qijun; Yang, Pu; Yang, Qi; Wang, Xinqi; Cui, Qian; Duan, Xujun; Liao, Wei; Chen, Huafu

    2018-05-01

    Traditional task-evoked brain activations are based on detection and estimation of signal change from the mean signal. By contrast, the low-frequency steady-state brain response (lfSSBR) reflects frequency-tagging activity at the fundamental frequency of the task presentation and its harmonics. Compared to the activity at these resonant frequencies, brain responses at nonresonant frequencies are largely unknown. Additionally, because the lfSSBR is defined by power change, we hypothesize using Parseval's theorem that the power change reflects brain signal variability rather than the change of mean signal. Using a face recognition task, we observed power increase at the fundamental frequency (0.05 Hz) and two harmonics (0.1 and 0.15 Hz) and power decrease within the infra-slow frequency band ( .955) of their spatial distribution and brain-behavior relationship at all frequency bands. Additionally, the reallocation of finite energy was observed across various brain regions and frequency bands, forming a particular spatiotemporal pattern. Overall, results from this study strongly suggest that frequency-specific power and variability may measure the same underlying brain activity and that these results may shed light on different mechanisms between lfSSBR and brain activation, and spatiotemporal characteristics of energy reallocation induced by cognitive tasks. © 2018 Wiley Periodicals, Inc.

  10. Application of back-propagation artificial neural network (ANN) to predict crystallite size and band gap energy of ZnO quantum dots

    Science.gov (United States)

    Pelicano, Christian Mark; Rapadas, Nick; Cagatan, Gerard; Magdaluyo, Eduardo

    2017-12-01

    Herein, the crystallite size and band gap energy of zinc oxide (ZnO) quantum dots were predicted using artificial neural network (ANN). Three input factors including reagent ratio, growth time, and growth temperature were examined with respect to crystallite size and band gap energy as response factors. The generated results from neural network model were then compared with the experimental results. Experimental crystallite size and band gap energy of ZnO quantum dots were measured from TEM images and absorbance spectra, respectively. The Levenberg-Marquardt (LM) algorithm was used as the learning algorithm for the ANN model. The performance of the ANN model was then assessed through mean square error (MSE) and regression values. Based on the results, the ANN modelling results are in good agreement with the experimental data.

  11. Valence band states in Si-based p-type delta-doped field effect transistors

    International Nuclear Information System (INIS)

    Martinez-Orozco, J C; Vlaev, Stoyan J

    2009-01-01

    We present tight-binding calculations of the hole level structure of δ-doped Field Effect Transistor in a Si matrix within the first neighbors sp 3 s* semi-empirical tight-binding model including spin. We employ analytical expressions for Schottky barrier potential and the p-type δ-doped well based on a Thomas-Fermi approximation, we consider these potentials as external ones, so in the computations they are added to the diagonal terms of the tight-binding Hamiltonian, by this way we have the possibility to study the energy levels behavior as we vary the backbone parameters in the system: the two-dimensional impurity density (p 2d ) of the p-type δ-doped well and the contact voltage (V c ). The aim of this calculation is to demonstrate that the tight-binding approximation is suitable for device characterization that permits us to propose optimal values for the input parameters involved in the device design.

  12. Valence band states in Si-based p-type delta-doped field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Orozco, J C; Vlaev, Stoyan J, E-mail: jcmover@correo.unam.m [Unidad Academica de Fisica, Universidad Autonoma de Zacatecas, Calzada Solidaridad esquina con Paseo la Bufa S/N, C.P. 98060, Zacatecas, Zac. (Mexico)

    2009-05-01

    We present tight-binding calculations of the hole level structure of delta-doped Field Effect Transistor in a Si matrix within the first neighbors sp{sup 3}s* semi-empirical tight-binding model including spin. We employ analytical expressions for Schottky barrier potential and the p-type delta-doped well based on a Thomas-Fermi approximation, we consider these potentials as external ones, so in the computations they are added to the diagonal terms of the tight-binding Hamiltonian, by this way we have the possibility to study the energy levels behavior as we vary the backbone parameters in the system: the two-dimensional impurity density (p{sub 2d}) of the p-type delta-doped well and the contact voltage (V{sub c}). The aim of this calculation is to demonstrate that the tight-binding approximation is suitable for device characterization that permits us to propose optimal values for the input parameters involved in the device design.

  13. Free Magnetic Energy in Solar Active Regions above the Minimum-Energy Relaxed State

    OpenAIRE

    Regnier, S.; Priest, E. R.

    2008-01-01

    To understand the physics of solar flares, including the local reorganization of the magnetic field and the acceleration of energetic particles, we have first to estimate the free magnetic energy available for such phenomena, which can be converted into kinetic and thermal energy. The free magnetic energy is the excess energy of a magnetic configuration compared to the minimum-energy state, which is a linear force-free field if the magnetic helicity of the configuration is conserved. We inves...

  14. The sensitivity of the electron transport within bulk zinc-blende gallium nitride to variations in the crystal temperature, the doping concentration, and the non-parabolicity coefficient associated with the lowest energy conduction band valley

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqua, Poppy; O' Leary, Stephen K., E-mail: stephen.oleary@ubc.ca [School of Engineering, The University of British Columbia, 3333 University Way, Kelowna, British Columbia V1V 1V7 (Canada)

    2016-09-07

    Within the framework of a semi-classical three-valley Monte Carlo simulation approach, we analyze the steady-state and transient electron transport that occurs within bulk zinc-blende gallium nitride. In particular, we examine how the steady-state and transient electron transport that occurs within this material changes in response to variations in the crystal temperature, the doping concentration, and the non-parabolicity coefficient associated with the lowest energy conduction band valley. These results are then contrasted with those corresponding to a number of other compound semiconductors of interest.

  15. Ground State Energy of the Modified Nambu-Goto String

    Science.gov (United States)

    Hadasz, Leszek

    We calculate, using zeta function regularization method, semiclassical energy of the Nambu-Goto string supplemented with the boundary, Gauss-Bonnet term in the action and discuss the tachyonic ground state problem.

  16. Ground state energy of the modified Nambu-Goto string

    OpenAIRE

    Hadasz, Leszek

    1997-01-01

    We calculate, using zeta function regularization method, semiclassical energy of the Nambu-Goto string supplemented with the boundary, Gauss-Bonnet term in the action and discuss the tachyonic ground state problem.

  17. Role of State Policy in Renewable Energy Development

    Energy Technology Data Exchange (ETDEWEB)

    Doris, E.; Busche, S.; Hockett, S.; McLaren, J.

    2009-07-01

    State policies can support renewable energy development by driving markets, providing certainty in the investment market, and incorporating the external benefits of the technologies into cost/benefit calculations. Using statistical analyses and policy design best practices, this paper quantifies the impact of state-level policies on renewable energy development in order to better understand the role of policy on development and inform policy makers on the policy mechanisms that provide maximum benefit. The results include the identification of connections between state policies and renewable energy development, as well as a discussion placing state policy efforts in context with other factors that influence the development of renewable energy (e.g. federal policy, resource availability, technology cost, public acceptance).

  18. Continental integration and energy demand in the United States

    International Nuclear Information System (INIS)

    Manning, D.J.

    2004-01-01

    This presentation highlighted some of the major issues regarding energy demand in the United States and continental integration. The energy markets in Canada and the United States are economically integrated with large cross-border investment. Therefore, the energy infrastructure can be significantly affected by inconsistencies between the two countries in policy, regulatory processes and fiscal regimes. The author discussed the inelasticity in the natural gas demand in the United States in the near-term, and how natural gas consumption, particularly for power generation, is greater than North America's supply capacity. New supplies such as liquefied natural gas and arctic gas are needed to meet growing demands. The role of renewable energy technologies and energy efficiency was also discussed. It was emphasized that imbalances in supply and demand inevitably lead to price volatility and that high prices are a major obstacle to economic growth. tabs., figs

  19. United States Data Center Energy Usage Report

    Energy Technology Data Exchange (ETDEWEB)

    Shehabi, Arman [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Smith, Sarah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sartor, Dale [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Brown, Richard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Herrlin, Magnus [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Koomey, Jonathan [Stanford Univ., CA (United States); Masanet, Eric [Northwestern Univ., Evanston, IL (United States); Horner, Nathaniel [Carnegie Mellon Univ., Pittsburgh, PA (United States); Azevedo, Inês [Carnegie Mellon Univ., Pittsburgh, PA (United States); Lintner, William [Dept. of Energy (DOE), Washington DC (United States)

    2016-06-01

    This report estimates historical data center electricity consumption back to 2000, relying on previous studies and historical shipment data, and forecasts consumption out to 2020 based on new trends and the most recent data available. Figure ES-1 provides an estimate of total U.S. data center electricity use (servers, storage, network equipment, and infrastructure) from 2000-2020. In 2014, data centers in the U.S. consumed an estimated 70 billion kWh, representing about 1.8% of total U.S. electricity consumption. Current study results show data center electricity consumption increased by about 4% from 2010-2014, a large shift from the 24% percent increase estimated from 2005-2010 and the nearly 90% increase estimated from 2000-2005. Energy use is expected to continue slightly increasing in the near future, increasing 4% from 2014-2020, the same rate as the past five years. Based on current trend estimates, U.S. data centers are projected to consume approximately 73 billion kWh in 2020.

  20. Energy landscapes of resting-state brain networks

    Directory of Open Access Journals (Sweden)

    Takamitsu eWatanabe

    2014-02-01

    Full Text Available During rest, the human brain performs essential functions such as memory maintenance, which are associated with resting-state brain networks (RSNs including the default-mode network (DMN and frontoparietal network (FPN. Previous studies based on spiking-neuron network models and their reduced models, as well as those based on imaging data, suggest that resting-state network activity can be captured as attractor dynamics, i.e., dynamics of the brain state toward an attractive state and transitions between different attractors. Here, we analyze the energy landscapes of the RSNs by applying the maximum entropy model, or equivalently the Ising spin model, to human RSN data. We use the previously estimated parameter values to define the energy landscape, and the disconnectivity graph method to estimate the number of local energy minima (equivalent to attractors in attractor dynamics, the basin size, and hierarchical relationships among the different local minima. In both of the DMN and FPN, low-energy local minima tended to have large basins. A majority of the network states belonged to a basin of one of a few local minima. Therefore, a small number of local minima constituted the backbone of each RSN. In the DMN, the energy landscape consisted of two groups of low-energy local minima that are separated by a relatively high energy barrier. Within each group, the activity patterns of the local minima were similar, and different minima were connected by relatively low energy barriers. In the FPN, all dominant energy were separated by relatively low energy barriers such that they formed a single coarse-grained global minimum. Our results indicate that multistable attractor dynamics may underlie the DMN, but not the FPN, and assist memory maintenance with different memory states.

  1. First-principles energy band calculation of Ruddlesden–Popper compound Sr{sub 3}Sn{sub 2}O{sub 7} using modified Becke–Johnson exchange potential

    Energy Technology Data Exchange (ETDEWEB)

    Kamimura, Sunao, E-mail: kamimura-sunao@che.kyutech.ac.jp [Department of Applied Chemistry, Faculty of Engineering, Kyushu Institute of Technology, 1-1 Sensuicho, Tobata, Kitakyushu, Fukuoka 804-8550 (Japan); National Institute of Advanced Industrial Science and Technology (AIST), 807-1 Shuku-machi, Tosu, Saga 841-0052 (Japan); Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1 Kasuga Kouen, Kasuga, Fukuoka 816-8580 Japan (Japan); Obukuro, Yuki [Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki 889-2192 (Japan); Matsushima, Shigenori, E-mail: smatsu@kct.ac.jp [Department of Creative Engineering, National Institute of Technology, Kitakyushu College, 5-20-1 Shii, Kokuraminami-ku, Kitakyushu, Fukuoka 802-0985 (Japan); Nakamura, Hiroyuki [Department of Creative Engineering, National Institute of Technology, Kitakyushu College, 5-20-1 Shii, Kokuraminami-ku, Kitakyushu, Fukuoka 802-0985 (Japan); Arai, Masao [Computational Materials Science Unit (CMSU), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan); Xu, Chao-Nan, E-mail: cn-xu@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 807-1 Shuku-machi, Tosu, Saga 841-0052 (Japan); Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1 Kasuga Kouen, Kasuga, Fukuoka 816-8580 Japan (Japan); International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2015-12-15

    The electronic structure of Sr{sub 3}Sn{sub 2}O{sub 7} is evaluated by the scalar-relativistic full potential linearized augmented plane wave (FLAPW+lo) method using the modified Becke–Johnson potential (Tran–Blaha potential) combined with the local density approximation correlation (MBJ–LDA). The fundamental gap between the valence band (VB) and conduction band (CB) is estimated to be 3.96 eV, which is close to the experimental value. Sn 5s states and Sr 4d states are predominant in the lower and upper CB, respectively. On the other hand, the lower VB is mainly composed of Sn 5s, 5p, and O 2p states, while the upper VB mainly consists of O 2p states. These features of the DOS are well reflected by the optical transition between the upper VB and lower CB, as seen in the energy dependence of the dielectric function. Furthermore, the absorption coefficient estimated from the MBJ–LDA is similar to the experimental result. - Graphical abstract: Calculated energy band structure along the symmetry lines of the first BZ of Sr{sub 3}Sn{sub 2}O{sub 7} crystal obtained using the MBJ potential. - Highlights: • Electronic structure of Sr{sub 3}Sn{sub 2}O{sub 7} is calculated on the basis of MBJ–LDA method for the first time. • Band gap of Sr{sub 3}Sn{sub 2}O{sub 7} is determined accurately on the basis of MBJ–LDA method. • The experimental absorption spectrum of Sr{sub 3}Sn{sub 2}O{sub 7} produced by MBJ–LDA is more accurate than that obtained by GGA method.

  2. Relation between plasmons and the valence-band density-of-states in polymethylmethacrylate - influence of ion irradiation on damage selectivity

    International Nuclear Information System (INIS)

    Moliton, J.P.; Jussiaux, C.; Trigaud, T.; Lazzaroni, R.; Lhost, O.; Bredas, J.L.; Kihn, Y.; Sevely, J.

    1996-01-01

    A physical model is presented that aims at rationalizing the selectivity of bond breakage observed when polymethylmethacrylate is irradiated by ions in the 10-500 keV energy range. This model, previously proposed by Brandt and Ritchie, is based on electronic collective effects. The coupling between the pure plasma oscillation at omega(p) and the oscillation of free electrons at [omega(k0)(2)](1/2) makes the whole electronic population resonant at the frequency omega(rp) = (omega(p)(2) + [omega(k0)(2)])(1/2). By computing the valence-band density of states, we calculate [omega(k0)(2)] and then deduce the theoretical value of omega(rp). On the other hand, we provide an experimental measurement of omega(rp) and study its dependence on ion fluence by electron-energy-loss spectroscopy. The validity of the model of Brandt and Ritchie is then discussed in the light of both theoretical and experimental data. (author)

  3. C6H6/Au(111): Interface dipoles, band alignment, charging energy, and van der Waals interaction

    International Nuclear Information System (INIS)

    Abad, E.; Martinez, J. I.; Flores, F.; Ortega, J.; Dappe, Y. J.

    2011-01-01

    We analyze the benzene/Au(111) interface taking into account charging energy effects to properly describe the electronic structure of the interface and van der Waals interactions to obtain the adsorption energy and geometry. We also analyze the interface dipoles and discuss the barrier formation as a function of the metal work-function. We interpret our DFT calculations within the induced density of interface states (IDIS) model. Our results compare well with experimental and other theoretical results, showing that the dipole formation of these interfaces is due to the charge transfer between the metal and benzene, as described in the IDIS model.

  4. Rotationally resolved pulsed-field ionization photoelectron bands for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12) in the energy range of 17.0-18.2 eV

    Energy Technology Data Exchange (ETDEWEB)

    Song, Y. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Evans, M. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Ng, C. Y. [Ames Laboratory, U.S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States); Hsu, C.-W. [Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Jarvis, G. K. [Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2000-01-15

    We have obtained rotationally resolved pulsed-field ionization photoelectron (PFI-PE) spectra for O{sub 2} in the energy range of 17.05-18.13 eV, covering the ionization transitions O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12,N{sup +})(<-)O{sub 2}(X {sup 3}{sigma}{sub g}{sup -},v{sup ''}=0,N{sup ''}). Although these O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}) PFI-PE bands have significant overlaps with vibrational bands for O{sub 2}{sup +}(a {sup 4}{pi}{sub u}) and O{sub 2}{sup +}(X {sup 2}{pi}{sub g}), we have identified all the O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12) bands by simulation of spectra obtained using supersonically cooled O{sub 2} samples with rotational temperatures {approx_equal}20 and 220 K. While these v{sup +}=0-12 PFI-PE bands represent the first rotationally resolved photoelectron data for O{sub 2}{sup +}(A {sup 2}{pi}{sub u}), the PFI-PE bands for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=9 and 10) are the first rotationally resolved spectroscopic data for these levels. The simulation also allows the determination of accurate ionization energies, vibrational constants, and rotational constants for O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=0-12). The analysis of the PFI-PE spectra supports the conclusion of the previous emission study that the O{sub 2}{sup +}(A {sup 2}{pi}{sub u},v{sup +}=9 and 10) states are strongly perturbed by a nearby electronic state. (c) 2000 American Institute of Physics.

  5. 78 FR 11167 - Meetings: State Energy Advisory Board

    Science.gov (United States)

    2013-02-15

    ... Advisory Committee Act (Pub. L. 92- 463; 86 Stat. 770) requires that public notice of these meetings be... carry out the Board's responsibilities as designated in the State Energy Efficiency Programs Improvement... and Renewable Energy (EERE), discuss new initiatives and technologies generated by the EERE program...

  6. Energy balance of the Sao Paulo State - 1995

    International Nuclear Information System (INIS)

    1996-01-01

    This work informs the energetic balance of Sao Paulo State - 1995, with information referring to the year 1994, containing the energy fluxes from primary and secondary energy sources in the main sectors of Sao Paulo economy. An electronic version for windows environment is also available. 81 figs., 179 tabs

  7. High energy chemistry. Modern state and trends in development

    International Nuclear Information System (INIS)

    Pikaev, A.K.

    1990-01-01

    In the review modern state of studies in the field of high energy chemistry is considered. The most important achievements and problems of further development of radiation chemistry, plasmochemistry, photochemistry, laser chemistry and some other branches of high energy chemistry are discussed

  8. An improved model of radiative transfer for the NLTE problem in the NIR bands of CO2 and CO molecules in the daytime atmosphere of Mars. 2. Population of vibrational states

    Science.gov (United States)

    Ogibalov, V. P.; Shved, G. M.

    2017-09-01

    The near-infrared (NIR) emission of the Martian atmosphere in the CO2 bands at 4.3, 2.7, 2.0, 1.6, 1.4, 1.3, 1.2, and 1.05 µm and in the CO bands at 4.7, 2.3, 1.6, and 1.2 µm is mainly generated under nonlocal thermodynamic equilibrium (NLTE) conditions for vibrational states, the transitions from which form the specified bands. The paper presents the results of simulations of the population of these states under NLTE for daytime conditions. In the cold high-latitude troposphere, the NLTE takes place much lower than in the troposphere under typical temperature conditions. If the NIR-radiation reflection from the surface is ignored, the population of high vibrational states substantially decreases, at least, in some layer of the lower atmosphere. However, inelastic collisions of CO2 and CO molecules with O atoms produce no considerable influence on the values of populations. The population of vibrational states, the transitions from which form NIR bands, is also almost insensitive to possible large values of the quenching-in-collision rate constants of vibrational states higher than CO2(0001). However, very large errors in the estimates of the population of vibrational states of the CO2 molecule (rather than the CO molecule!) can be caused by the uncertainty in the values of the rate constant of exchange between CO2 molecules by the energy quantum of the asymmetric stretching vibrational mode. For this intermolecular exchange, we recommend a possible way to restrict the vibrational excitation degree of the molecule that is a collision partner and to maintain simultaneously a sufficiently high accuracy in the population estimate.

  9. Present state and future of new energy technology development

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, N

    1976-08-01

    The Sunshine Project was begun in 1973 by the Japanese Ministry of Industry to investigate all alternative energy sources other than nuclear. The project is subdivided into four separate areas, those being solar energy, geothermal energy, liquefaction and gasification of coal, and hydrogen fuel. This article describes the present state of these technologies and their probable future development. Although hydrogen fuel and coal liquefaction/gasification are still in the basic research stage solar and geothermal technologies are already well developed.

  10. Energy and environmental policy in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Hibbard, P.J.; Tierney, S.F

    2003-08-15

    The energy and environmental policies of the United States are, like those of any nation, greatly shaped by a particular economic, institutional and political context. Understanding that context is useful for providing insights into the substance of US energy and environmental policy, the challenges and opportunities associated with it, and future potential for change. This article examines this policy context, focusing on the interaction of energy and environmental policies related to the electric industry. (author)

  11. Energy and environmental policy in the United States

    International Nuclear Information System (INIS)

    Hibbard, P.J.; Tierney, S.F.

    2003-08-01

    The energy and environmental policies of the United States are, like those of any nation, greatly shaped by a particular economic, institutional and political context. Understanding that context is useful for providing insights into the substance of US energy and environmental policy, the challenges and opportunities associated with it, and future potential for change. This article examines this policy context, focusing on the interaction of energy and environmental policies related to the electric industry. (author)

  12. State and possibilities for development of renewable energy in Bulgaria

    International Nuclear Information System (INIS)

    Varbanov, Marian; Temelkova, Maria

    2011-01-01

    After EU accession, Bulgaria adopted the following indicative goal: 16% of gross domestic energy consumption in 2020 to be produced from renewables. This has created favorable conditions and strong interest of Bulgarian and foreign business to invest in renewables. This interest is materialized in a boom in design and construction of the renewable energy installations. The paper examines the current state and opportunities for development of this sector in Bulgaria. Keywords: renewable energy, hydro power, wind power, solar power

  13. The formation of α-phase SnS nanorods by PVP assisted polyol synthesis: Phase stability, micro structure, thermal stability and defects induced energy band transitions

    Energy Technology Data Exchange (ETDEWEB)

    Baby, Benjamin Hudson; Mohan, D. Bharathi, E-mail: d.bharathimohan@gmail.com

    2017-05-01

    We report the formation of single phase of SnS nanostructure through PVP assisted polyol synthesis by varying the source concentration ratio (Sn:S) from 1:1M to 1:12M. The effect of PVP concentration and reaction medium towards the preparation of SnS nanostructure is systematically studied through confocal Raman spectrometer, X-ray diffraction, thermogravimetry analysis, scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, UV–Vis–NIR absorption and fluorescence spectrophotometers. The surface morphology of SnS nanostructure changes from nanorods to spherical shape with increasing PVP concentration from 0.15M to 0.5M. Raman analysis corroborates that Raman active modes of different phases of Sn-S are highly active when Raman excitation energy is slightly greater than the energy band gap of the material. The presence of intrinsic defects and large number of grain boundaries resulted in an improved thermal stability of 20 °C during the phase transition of α-SnS. Band gap calculation from tauc plot showed the direct band gap of 1.5 eV which is attributed to the single phase of SnS, could directly meet the requirement of an absorber layer in thin film solar cells. Finally, we proposed an energy band diagram for as synthesized single phase SnS nanostructure based on the experimental results obtained from optical studies showing the energy transitions attributed to band edge transition and also due to the presence of intrinsic defects. - Highlights: • PVP stabilizes the orthorhombic (α) phase of SnS. • Optical band gap of P type SnS tuned by PVP for photovoltaic applications. • The formation of Sn rich SnS phase is investigated through XPS analysis. • Intrinsic defects enhance the thermal stability of α-SnS. • The feasibility of energy transition liable to point defects is discussed.

  14. Communication: Broad manifold of excitonic states in light-harvesting complex 1 promotes efficient unidirectional energy transfer in vivo

    Science.gov (United States)

    Sohail, Sara H.; Dahlberg, Peter D.; Allodi, Marco A.; Massey, Sara C.; Ting, Po-Chieh; Martin, Elizabeth C.; Hunter, C. Neil; Engel, Gregory S.

    2017-10-01

    In photosynthetic organisms, the pigment-protein complexes that comprise the light-harvesting antenna exhibit complex electronic structures and ultrafast dynamics due to the coupling among the chromophores. Here, we present absorptive two-dimensional (2D) electronic spectra from living cultures of the purple bacterium, Rhodobacter sphaeroides, acquired using gradient assisted photon echo spectroscopy. Diagonal slices through the 2D lineshape of the LH1 stimulated emission/ground state bleach feature reveal a resolvable higher energy population within the B875 manifold. The waiting time evolution of diagonal, horizontal, and vertical slices through the 2D lineshape shows a sub-100 fs intra-complex relaxation as this higher energy population red shifts. The absorption (855 nm) of this higher lying sub-population of B875 before it has red shifted optimizes spectral overlap between the LH1 B875 band and the B850 band of LH2. Access to an energetically broad distribution of excitonic states within B875 offers a mechanism for efficient energy transfer from LH2 to LH1 during photosynthesis while limiting back transfer. Two-dimensional lineshapes reveal a rapid decay in the ground-state bleach/stimulated emission of B875. This signal, identified as a decrease in the dipole strength of a strong transition in LH1 on the red side of the B875 band, is assigned to the rapid localization of an initially delocalized exciton state, a dephasing process that frustrates back transfer from LH1 to LH2.

  15. Innovation, renewable energy, and state investment: Case studies of leading clean energy funds

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, Ryan; Bolinger, Mark; Milford, Lewis; Porter, Kevin; Clark, Roger

    2002-09-01

    Over the last several years, many U.S. states have established clean energy funds to help support the growth of renewable energy markets. Most often funded by system-benefits charges (SBC), the 15 states that have established such funds are slated to collect nearly $3.5 billion from 1998 to 2012 for renewable energy investments. These clean energy funds are expected to have a sizable impact on the energy future of the states in which the funds are being collected and used. For many of the organizations tapped to administer these funds, however, this is a relatively new role that presents the challenge of using public funds in the most effective and innovative fashion possible. Fortunately, each state is not alone in its efforts; many other U.S. states and a number of countries are undertaking similar efforts. Early lessons are beginning to be learned by clean energy funds about how to effectively target public funds towards creating and building renewable energy markets. A number of innovative programs have already been developed that show significant leadership by U.S. states in supporting renewable energy. It is important that clean energy fund administrators learn from this emerging experience.

  16. Observation of states beyond band termination in 156,157,158Er and strongly deformed structures in 173,174,175Hf

    International Nuclear Information System (INIS)

    Riley, M A; Djongolov, M K; Evans, A O

    2006-01-01

    High-spin terminating bands in heavy nuclei were first identified in nuclei around 158 Er 90 . While examples of terminating states have been identified in a number of erbium isotopes, almost nothing is known about the states lying beyond band termination. In the present work, the high-spin structure of 156,157,158 Er has been studied using the Gammasphere spectrometer. The subject of triaxial superdeformation and 'wobbling' modes in Lu nuclei has rightly attracted a great deal of attention. Very recently four strongly or superdeformed (SD) sequences have been observed in 174 Hf, and cranking calculations using the Ultimate Cranker code predict that such structures may have significant triaxial deformation. We have performed two experiments in an attempt to verify the possible triaxial nature of these bands. A lifetime measurement was performed to confirm the large (and similar) deformation of the bands. In addition, a high-statistics, thin-target experiment took place to search for linking transitions between the SD bands, possible wobbling modes, and new SD band structures

  17. A jet-dominated model for a broad-band spectral energy distribution of the nearby low-luminosity active galactic nucleus in M94

    Science.gov (United States)

    van Oers, Pieter; Markoff, Sera; Uttley, Phil; McHardy, Ian; van der Laan, Tessel; Donovan Meyer, Jennifer; Connors, Riley

    2017-06-01

    We have compiled a new multiwavelength spectral energy distribution (SED) for the closest obscured low-ionization emission-line region active galactic nucleus (AGN), NGC 4736, also known as M94. The SED comprises mainly high-resolution (mostly sub-arcsecond, or, at the distance to M94, ≲23 pc from the nucleus) observations from the literature, archival data, as well as previously unpublished sub-millimetre data from the Plateau de Bure Interferometer (PdBI) and the Combined Array for Research in Millimeter-wave Astronomy, in conjunction with new electronic MultiElement Radio Interferometric Network (e-MERLIN) L-band (1.5 GHz) observations. Thanks to the e-MERLIN resolution and sensitivity, we resolve for the first time a double structure composed of two radio sources separated by ˜1 arcsec, previously observed only at higher frequency. We explore this data set, which further includes non-simultaneous data from the Very Large Array, the Gemini telescope, the Hubble Space Telescope and the Chandra X-ray observatory, in terms of an outflow-dominated model. We compare our results with previous trends found for other AGN using the same model (NGC 4051, M81*, M87 and Sgr A*), as well as hard- and quiescent-state X-ray binaries. We find that the nuclear broad-band spectrum of M94 is consistent with a relativistic outflow of low inclination. The findings in this work add to the growing body of evidence that the physics of weakly accreting black holes scales with mass in a rather straightforward fashion.

  18. Dark energy cosmology with generalized linear equation of state

    International Nuclear Information System (INIS)

    Babichev, E; Dokuchaev, V; Eroshenko, Yu

    2005-01-01

    Dark energy with the usually used equation of state p = wρ, where w const 0 ), where the constants α and ρ 0 are free parameters. This non-homogeneous linear equation of state provides the description of both hydrodynamically stable (α > 0) and unstable (α < 0) fluids. In particular, the considered cosmological model describes the hydrodynamically stable dark (and phantom) energy. The possible types of cosmological scenarios in this model are determined and classified in terms of attractors and unstable points by using phase trajectories analysis. For the dark energy case, some distinctive types of cosmological scenarios are possible: (i) the universe with the de Sitter attractor at late times, (ii) the bouncing universe, (iii) the universe with the big rip and with the anti-big rip. In the framework of a linear equation of state the universe filled with a phantom energy, w < -1, may have either the de Sitter attractor or the big rip

  19. Power from Perspective: Potential future United States energy portfolios

    International Nuclear Information System (INIS)

    Tonn, Bruce; Healy, K.C.; Gibson, Amy; Ashish, Ashutosh; Cody, Preston; Beres, Drew; Lulla, Sam; Mazur, Jim; Ritter, A.J.

    2009-01-01

    This paper presents United States energy portfolios for the year 2030, developed from seven different Perspectives. The Perspectives are characterized by different weights placed on fourteen defining values (e.g., cost, social acceptance). The portfolios were constructed to achieve three primary goals, energy independence, energy security, and greenhouse gas reductions. The portfolios are also evaluated over a comprehensive set of secondary criteria (e.g., economic growth, technical feasibility). It is found that very different portfolios based on very different defining values can achieve the three primary goals. Commonalities among the portfolios include reliance upon cellulosic ethanol, nuclear power, and energy efficiency to meet year 2030 energy demands. It is concluded that the US energy portfolio must be diverse and to achieve national energy goals will require an explicit statement of goals, a strong role for government, and coordinated action across society

  20. Effect of MnO2 doping and temperature treatment on optical energy band gap properties in Zn-Bi-Ti-O varistor ceramics

    International Nuclear Information System (INIS)

    Ghazali, M. S. M.; Abdullah, W. R. W.; Zakaria, A.; Kamari, H. M.; Rizwan, Z.

    2016-01-01

    In this study, the optical band-gap energy ( Eg ) was investigated with respect to MnO 2 and sintering temperatures on ZnO based varistor ceramics. Eg of the ceramic (99-x) mol% ZnO + 0.5 mol% Bi 2 O 3 + 0.5 mol% TiO 2 + × MnO 2 where × = 0, 0.2, 0.4, 0.6 and 0.8 mol%, were determined using UV-Vis spectrophotometer. The samples was prepared through solid-state route and sintered at the sintering temperature from 1110, 1140 and 1170 °C for 45 and 90 min in open air. At no doping of MnO 2 , the values of Eg are 2.991 ± 0.001, 2.989 ± 0.001 eV for 45 and 90 min sintering time; respectively. Eg was decreased to 2.192 ± 0.001 eV at 1140 °C at 45 min sintering time. Similar result of Eg was observed at longer heat treatment. Further addition of dopant causing the Eg decreases rapidly to 2.099 and 2.106 ± 0.001 eV at 45 and 90 min sintering time; respectively. XRD analysis indicates that there is hexagonal ZnO and secondary phases, Zn 2 MnO 4 , Bi 4 Ti 3 O 12 and Zn 2 Ti 3 O 8 . The relative density of the sintered ceramics decreased or remain constant with the increase of MnO 2 concentration for 45 min sintering time, however, further prolong sintering time; the relative density decreases form 90.25 to 88.35%. This indicates the pores are increasing with the increase of heat treatment. The variation of sintering temperatures to the optical band gap energy of based ZnO varistor doped with MnO 2 due to the formation of interface states. (paper)

  1. Green energy laws and Republican legislators in the United States

    International Nuclear Information System (INIS)

    Coley, Jonathan S.; Hess, David J.

    2012-01-01

    The policy context for green energy laws in the United States has changed over the past few years, because the Republican Party has increasingly opposed renewable electricity and other green energy policies. In this study, we draw on a database of 6071 votes on RPS (renewable portfolio standards) and PACE (Property-Assessed Clean Energy) laws by individual state legislators in the United States to examine the circumstances shaping Republican votes for green energy laws from 2007–2011. We find that votes on these laws are indeed increasingly partisan, with Republicans supporting RPS laws especially less than Democrats. However, Republicans' support for these laws is higher in states with weaker fossil fuel industries. Furthermore, Republicans tend to support the laws where median household income is lower, environmental organizations are weaker, labor-environmental coalitions are absent, and the proportion of Democrats in the legislature is lower, suggesting a reactive effect against green energy policies in more progressive settings. - Highlights: ► We analyze Republican votes for state RPS and PACE laws from 2007–2011. ► Support for RPS laws declined, while support for PACE laws remained steady. ► Support for both laws is lower in states with strong fossil fuel industries. ► Support for both laws is lower in more Democratic legislatures.

  2. Determination of the impact of Bi content on the valence band energy of GaAsBi using x-ray photoelectron spectroscopy

    Directory of Open Access Journals (Sweden)

    K. Collar

    2017-07-01

    Full Text Available We investigate the change of the valence band energy of GaAs1-xBix (0band energy per addition of 1 % Bi is determined for strained and unstrained thin films using a linear approximation applicable to the dilute regime. Spectroscopic ellipsometry (SE was used as a complementary technique to determine the change in GaAsBi bandgap resulting from Bi addition. Analysis of SE and XPS data together supports the conclusion that ∼75% of the reduction in the bandgap is in the valence band for a compressively strained, dilute GaAsBi thin film at room temperature.

  3. The energy content of restaurant foods without stated calorie information.

    Science.gov (United States)

    Urban, Lorien E; Lichtenstein, Alice H; Gary, Christine E; Fierstein, Jamie L; Equi, Ashley; Kussmaul, Carolyn; Dallal, Gerard E; Roberts, Susan B

    2013-07-22

    National recommendations for the prevention and treatment of obesity emphasize reducing energy intake through self-monitoring food consumption. However, little information is available on the energy content of foods offered by nonchain restaurants, which account for approximately 50% of restaurant locations in the United States. To measure the energy content of foods from independent and small-chain restaurants that do not provide stated information on energy content. We used bomb calorimetry to determine the dietary energy content of the 42 most frequently purchased meals from the 9 most common restaurant categories. Independent and small-chain restaurants were randomly selected, and 157 individual meals were analyzed. Area within 15 miles of downtown Boston. A random sample of independent and small-chain restaurants. Dietary energy. All meal categories provided excessive dietary energy. The mean energy content of individual meals was 1327 (95% CI, 1248-1406) kcal, equivalent to 66% of typical daily energy requirements. We found a significant effect of food category on meal energy (P ≤ .05), and 7.6% of meals provided more than 100% of typical daily energy requirements. Within-meal variability was large (average SD, 271 kcal), and we found no significant effect of restaurant establishment or size. In addition, meal energy content averaged 49% greater than those of popular meals from the largest national chain restaurants (P restaurants have been criticized for offering meals with excess dietary energy. This study finds that independent and small-chain restaurants, which provide no nutrition information, also provide excessive dietary energy in amounts apparently greater than popular meals from chain restaurants or information in national food databases. A national requirement for accurate calorie labeling in all restaurants may discourage menus offering unhealthy portions and would allow consumers to make informed choices about ordering meals that promote weight

  4. Forbidden energy band gap in diluted a-Ge{sub 1-x}Si{sub x}:N films

    Energy Technology Data Exchange (ETDEWEB)

    Guarneros, C.; Rebollo-Plata, B. [Posgrado en Fisica Aplicada, Facultad de Ciencias Fisico-Matematicas, Benemerita Universidad Autonoma de Puebla, Blvd. 14 Sur 6301, Col. San Manuel, 72570, Puebla (Mexico); Lozada-Morales, R., E-mail: rlozada@fcfm.buap.mx [Posgrado en Fisica Aplicada, Facultad de Ciencias Fisico-Matematicas, Benemerita Universidad Autonoma de Puebla, Blvd. 14 Sur 6301, Col. San Manuel, 72570, Puebla (Mexico); Espinosa-Rosales, J.E. [Posgrado en Fisica Aplicada, Facultad de Ciencias Fisico-Matematicas, Benemerita Universidad Autonoma de Puebla, Blvd. 14 Sur 6301, Col. San Manuel, 72570, Puebla (Mexico); Portillo-Moreno, J. [Facultad de Ciencias Quimicas, Benemerita Universidad Autonoma de Puebla, Blvd. 14 Sur 6301, Col. San Manuel, 72570, Puebla (Mexico); Zelaya-Angel, O. [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, PO Box 14-740, Mexico 07360 D.F. (Mexico)

    2012-06-01

    By means of electron gun evaporation Ge{sub 1-x}Si{sub x}:N thin films, in the entire range 0 {<=} x {<=} 1, were prepared on Si (100) and glass substrates. The initial vacuum reached was 6.6 Multiplication-Sign 10{sup -4} Pa, then a pressure of 2.7 Multiplication-Sign 10{sup -2} Pa of high purity N{sub 2} was introduced into the chamber. The deposition time was 4 min. Crucible-substrate distance was 18 cm. X-ray diffraction patterns indicate that all the films were amorphous (a-Ge{sub 1-x}Si{sub x}:N). The nitrogen concentration was of the order of 1 at% for all the films. From optical absorption spectra data and by using the Tauc method the energy band gap (E{sub g}) was calculated. The Raman spectra only reveal the presence of Si-Si, Ge-Ge, and Si-Ge bonds. Nevertheless, infrared spectra demonstrate the existence of Si-N and Ge-N bonds. The forbidden energy band gap (E{sub g}) as a function of x in the entire range 0 {<=} x {<=} 1 shows two well defined regions: 0 {<=} x {<=} 0.67 and 0.67 {<=} x {<=} 1, due to two different behaviors of the band gap, where for x > 0.67 exists an abruptly change of E{sub g}(x). In this case E{sub g}(x) versus x is different to the variation of E{sub g} in a-Ge{sub 1-x}Si{sub x} and a-Ge{sub 1-x}Si{sub x}:H. This fact can be related to the formation of Ge{sub 3}N{sub 4} and GeSi{sub 2}N{sub 4} when x {<=} 0.67, and to the formation of Si{sub 3}N{sub 4} and GeSi{sub 2}N{sub 4} for 0.67 {<=} x. - Highlights: Black-Right-Pointing-Pointer Nitrogen doped amorphous Ge{sub 1-x}Si{sub x} thin films are grown by electron gun technique. Black-Right-Pointing-Pointer Nitrogen atoms on E{sub g} of the a-Ge{sub 1-x}Si{sub x} films in the 0 Pound-Sign x Pound-Sign 1 range are analyzed. Black-Right-Pointing-Pointer Variation in 0 Pound-Sign x Pound-Sign 1 range shows a warped change of E{sub g} in 1.0 - 3.6 eV range. Black-Right-Pointing-Pointer The change in E{sub g}(x) behavior when x {approx} 0.67 was associated with Ge{sub 2}SiN{sub 4

  5. B(M1) values in the band-crossing of shears bands in 197Pb

    Science.gov (United States)

    Krücken, R.; Cooper, J. R.; Beausang, C. W.; Novak, J. R.; Dewald, A.; Klug, T.; Kemper, G.; von Brentano, P.; Carpenter, M.; Wiedenhöver, I.

    We present details of the band crossing mechanism of shears bands using the example of 197Pb. Absolute reduced matrix elements B(M1) were determined by means of a RDM lifetime measurement in one of the shears bands in 197Pb. The experiment was performed using the New Yale Plunger Device (NYPD) in conjunction with the Gammasphere array. Band mixing calculations on the basis of the semi-classical model of the shears mechanism are used to describe the transition matrix elements B(M1) and energies throughout the band-crossing regions. Good agreement with the data was obtained and the detailed composition of the states in the shears band are discussed.

  6. Quasi-bound states in continuum

    International Nuclear Information System (INIS)

    Nakamura, Hiroaki; Hatano, Naomichi; Garmon, Sterling; Petrosky, Tomio

    2007-08-01

    We report the prediction of quasi-bound states (resonant states with very long lifetimes) that occur in the eigenvalue continuum of propagating states for a wide region of parameter space. These quasi-bound states are generated in a quantum wire with two channels and an adatom, when the energy bands of the two channels overlap. A would-be bound state that lays just below the upper energy band is slightly destabilized by the lower energy band and thereby becomes a resonant state with a very long lifetime (a second QBIC lays above the lower energy band). (author)

  7. Energy consumption, income, and carbon emissions in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Soytas, Ugur [Department of Business Administration, Middle East Technical University Ankara, Turkey 06531 (Turkey); Sari, Ramazan [Department of Economics, Abant Izzet Baysal University Bolu, Turkey 14280 (Turkey); Ewing, Bradley T. [Rawls College of Business Texas Tech University Lubbock, TX 79409-2101 (United States)

    2007-05-15

    This paper investigates the effect of energy consumption and output on carbon emissions in the United States. Earlier research focused on testing the existence and/or shape of an environmental Kuznets curve without taking energy consumption into account. We investigate the Granger causality relationship between income, energy consumption, and carbon emissions, including labor and gross fixed capital formation in the model. We find that income does not Granger cause carbon emissions in the US in the long run, but energy use does. Hence, income growth by itself may not become a solution to environmental problems. (author)

  8. Design Considerations of a Solid State Thermal Energy Storage

    Science.gov (United States)

    Janbozorgi, Mohammad; Houssainy, Sammy; Thacker, Ariana; Ip, Peggy; Ismail, Walid; Kavehpour, Pirouz

    2016-11-01

    With the growing governmental restrictions on carbon emission, renewable energies are becoming more prevalent. A reliable use of a renewable source however requires a built-in storage to overcome the inherent intermittent nature of the available energy. Thermal design of a solid state energy storage has been investigated for optimal performance. The impact of flow regime, laminar vs. turbulent, on the design and sizing of the system is also studied. The implications of low thermal conductivity of the storage material are discussed and a design that maximizes the round trip efficiency is presented. This study was supported by Award No. EPC-14-027 Granted by California Energy Commission (CEC).

  9. PROBING THE IONIZATION STATES OF POLYCYCLIC AROMATIC HYDROCARBONS VIA THE 15–20 μm EMISSION BANDS

    Energy Technology Data Exchange (ETDEWEB)

    Shannon, M. J.; Stock, D. J.; Peeters, E., E-mail: mshann3@uwo.ca [Department of Physics and Astronomy, University of Western Ontario, London, ON, N6A 3K7 (Canada)

    2015-10-01

    We report new correlations between ratios of band intensities of the 15–20 μm emission bands of polycyclic aromatic hydrocarbons (PAHs) in a sample of 57 sources observed with the Spitzer/Infrared Spectrograph. This sample includes Large Magellanic Cloud point sources from the SAGE-Spec survey, nearby galaxies from the Spitzer Infrared Nearby Galaxies Survey survey, two Galactic interstellar medium cirrus sources, and the spectral maps of the Galactic reflection nebulae NGC 2023 and NGC 7023. We find that the 16.4, 17.4, and 17.8 μm band intensities are inter-correlated in all environments. In NGC 2023 and NGC 7023 these bands also correlate with the 11.0 and 12.7 μm band intensities. The 15.8 μm band correlates only with the 15–18 μm plateau and the 11.2 μm emission. We examine the spatial morphology of these bands and introduce radial cuts. We find that these bands can be spatially organized into three sets: the 12.7, 16.4, and 17.8 μm bands; the 11.2, 15.8 μm bands and the 15–18 μm plateau; and the 11.0 and 17.4 μm bands. We also find that the spatial distribution of the 12.7, 16.4, and 17.8 μm bands can be reconstructed by averaging the spatial distributions of the cationic 11.0 μm and neutral 11.2 μm bands. We conclude that the 17.4 μm band is dominated by cations, the 15.8 μm band by neutral species, and the 12.7, 16.4, and 17.8 μm bands by a combination of the two. These results highlight the importance of PAH ionization for spatially differentiating sub-populations by their 15–20 μm emission variability.

  10. Band bending in Au/Pb(Zr,Ti)O3 investigated by X-ray photoelectron spectroscopy: Dependence on the initial state of the film

    International Nuclear Information System (INIS)

    Apostol, Nicoleta G.; Stoflea, Laura E.; Lungu, George A.; Tanase, Liviu C.; Chirila, Cristina; Frunza, Ligia; Pintilie, Lucian; Teodorescu, Cristian M.

    2013-01-01

    This work presents a systematic investigation by X-ray photoelectron spectroscopy of the mechanisms of interface formation and band bending for Au/Pb(Zr,Ti)O 3 (PZT) layers grown on SrTiO 3 (001) with a SrRuO 3 buffer layer, as function on the initial state of the PZT surface. After isolating the chemical effects, such as the formation of metal Pb at some surfaces, the evolution of the core levels with Au deposition allows one to simultaneously investigate the Schottky barrier formation and the built-in potential effects (charging induced by the static ferroelectric polarization). Areas of the sample with outwards P (+) and no polarization perpendicular to the surface P (0) are identified for all samples. Only the freshly prepared sample exhibited inward polarization areas P (−) . The built-in potential is on the order of 0.9 eV, while the Schottky band bending ranges from 0.2 to 0.6 eV towards lower absolute energies, therefore indicating that the work function of PZT exceeds that of Au deposited. We report also a chemically differentiate value of the built-in potential, manifested by a preferential distribution of the charge accumulated at the surface on Ti and O atoms. The O 1s and Ti 2p core levels manifest quite strong variations with the Au thickness for freshly prepared samples, resulting in shifts on the order of 2 eV towards lower binding energies. Au deposited on areas with an outward polarization is positively charged by the same potential as atoms from the PZT film (0.8–0.9 eV), whereas Au deposited on areas with an inward polarization forms a continuous grounded layer, which progressively pumps the accumulated charge and removes the polarization of these areas. - Highlights: • Assessment by XPS of areas with different ferroelectric polarization. • Inwards polarized areas identified only on freshly prepared substrates. • Follow-up of the Schottky barrier formed at Au/PZT(001) interfaces. • Inwards polarized areas exhibit higher binding

  11. Factors of Renewable Energy Deployment and Empirical Studies of United States Wind Energy

    Science.gov (United States)

    Can Sener, Serife Elif

    Considered essential for countries' development, energy demand is growing worldwide. Unlike conventional sources, the use of renewable energy sources has multiple benefits, including increased energy security, sustainable economic growth, and pollution reduction, in particular greenhouse gas emissions. Nevertheless, there is a considerable difference in the share of renewable energy sources in national energy portfolios. This dissertation contains a series of studies to provide an outlook on the existing renewable energy deployment literature and empirically identify the factors of wind energy generation capacity and wind energy policy diffusion in the U.S. The dissertation begins with a systematic literature review to identify drivers and barriers which could help in understanding the diverging paths of renewable energy deployment for countries. In the analysis, economic, environmental, and social factors are found to be drivers, whereas political, regulatory, technical potential and technological factors are not classified as either a driver or a barrier (i.e., undetermined). Each main category contains several subcategories, among which only national income is found to have a positive impact, whereas all other subcategories are considered undetermined. No significant barriers to the deployment of renewable energy sources are found over the analyzed period. Wind energy deployment within the states related to environmental and economic factors was seldom discussed in the literature. The second study of the dissertation is thus focused on the wind energy deployment in the United States. Wind energy is among the most promising clean energy sources and the United States has led the world in per capita newly installed generation capacity since 2000. In the second study, using a fixed-effects panel data regression analysis, the significance of a number of economic and environmental factors are investigated for 39 states from 2000 to 2015. The results suggested that the

  12. Exciton spectra and energy band structure of Cu{sub 2}ZnSiSe{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Guc, M., E-mail: gmax@phys.asm.md [Institute of Applied Physics, Academy of Sciences of Moldova, Academiei Str. 5, Chisinau MD 2028, Republic of Moldova (Moldova, Republic of); Levcenko, S. [Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Dermenji, L. [Institute of Applied Physics, Academy of Sciences of Moldova, Academiei Str. 5, Chisinau MD 2028, Republic of Moldova (Moldova, Republic of); Gurieva, G. [Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Schorr, S. [Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Free University Berlin, Institute of Geological Sciences, Malteserstr. 74-100, Berlin (Germany); Syrbu, N.N. [Technical University of Moldova, Chisinau MD-2004, Republic of Moldova (Moldova, Republic of); Arushanov, E. [Institute of Applied Physics, Academy of Sciences of Moldova, Academiei Str. 5, Chisinau MD 2028, Republic of Moldova (Moldova, Republic of)

    2014-02-25

    Highlights: • Reflection spectra of Cu{sub 2}ZnSiSe{sub 4} were studied for E ⊥ c and E || c light polarizations. • Four excitonic series are revealed in the reflection spectra at 10 K. • Model of exciton dispersion and the presence of a dead-layer. • Exciton Rydberg energies and free carriers effective masses were calculated. • Reflectivity for E ⊥ c and E || c were analyzed in the region 3–6 eV at 300 K. -- Abstract: Exciton spectra are studied in Cu{sub 2}ZnSiSe{sub 4} single crystals at 10 and 300 K by means of reflection spectroscopy. The exciton parameters, dielectric constant and free carriers effective masses are deduced from experimental spectra by calculations in the framework of a model taking into account the spatial dispersion and the presence of a dead-layer. The structure found in the reflectivity was analyzed and related to the theoretical electronic band structure of close related Cu{sub 2}ZnSiS{sub 4} semiconductor.

  13. ALD grown nanostructured ZnO thin films: Effect of substrate temperature on thickness and energy band gap

    Directory of Open Access Journals (Sweden)

    Javed Iqbal

    2016-10-01

    Full Text Available Nanostructured ZnO thin films with high transparency have been grown on glass substrate by atomic layer deposition at various temperatures ranging from 100 °C to 300 °C. Efforts have been made to observe the effect of substrate temperature on the thickness of the deposited thin films and its consequences on the energy band gap. A remarkably high growth rate of 0.56 nm per cycle at a substrate temperature of 200 °C for ZnO thin films have been achieved. This is the maximum growth rate for ALD deposited ZnO thin films ever reported so far to the best of our knowledge. The studies of field emission scanning electron microscopy and X-ray diffractometry patterns confirm the deposition of uniform and high quality nanosturtured ZnO thin films which have a polycrystalline nature with preferential orientation along (100 plane. The thickness of the films deposited at different substrate temperatures was measured by ellipsometry and surface profiling system while the UV–visible and photoluminescence spectroscopy studies have been used to evaluate the optical properties of the respective thin films. It has been observed that the thickness of the thin film depends on the substrate temperatures which ultimately affect the optical and structural parameters of the thin films.

  14. Dissociation energy of the ground state of NaH

    International Nuclear Information System (INIS)

    Huang, Hsien-Yu; Lu, Tsai-Lien; Whang, Thou-Jen; Chang, Yung-Yung; Tsai, Chin-Chun

    2010-01-01

    The dissociation energy of the ground state of NaH was determined by analyzing the observed near dissociation rovibrational levels. These levels were reached by stimulated emission pumping and fluorescence depletion spectroscopy. A total of 114 rovibrational levels in the ranges 9≤v '' ≤21 and 1≤J '' ≤14 were assigned to the X 1 Σ + state of NaH. The highest vibrational level observed was only about 40 cm -1 from the dissociation limit in the ground state. One quasibound state, above the dissociation limit and confined by the centrifugal barrier, was observed. Determining the vibrational quantum number at dissociation v D from the highest four vibrational levels yielded the dissociation energy D e =15 815±5 cm -1 . Based on new observations and available data, a set of Dunham coefficients and the rotationless Rydberg-Klein-Rees curve were constructed. The effective potential curve and the quasibound states were discussed.

  15. Structure of dipole bands in 106In

    International Nuclear Information System (INIS)

    Deo, A. Y.; Palit, R.; Naik, Z.; Joshi, P. K.; Mazumdar, I.; Sihotra, S.; Mehta, D.; Kumar, S.; Chakrabarti, R.; Kshetri, R.; Jain, H. C.

    2009-01-01

    High spin states in neutron-deficient 106 In were investigated using 78 Se( 32 S,p3n) reaction at 125 MeV. The level scheme is extended up to 7 MeV of excitation energy for the negative parity states constituting four dipole bands, and the positive parity states which mainly exhibit single-particle excitations are extended up to 5 MeV. Projected deformed Hartree-Fock calculations were carried out to understand the configurations of different bands in this nucleus.

  16. Itinerant ferromagnetism in the narrow band limit

    CERN Document Server

    Liu, S H

    2000-01-01

    It is shown that in the narrow band, strong interaction limit the paramagnetic state of an itinerant ferromagnet is described by the disordered local moment state. As a result, the Curie temperature is orders of magnitude lower than what is expected from the large exchange splitting of the spin bands. An approximate analysis has also been carried out for the partially ordered state, and the result explains the temperature evolvement of the magnetic contributions to the resistivity and low-energy optical conductivity of CrO sub 2.

  17. Renewable energies in the EU-Accession States

    International Nuclear Information System (INIS)

    Reiche, Danyel

    2006-01-01

    The aim of this article is to discuss obstacles and success conditions for renewable energy sources in the EU-Accession States and to compare them with the framework in the EU-15. Besides the ten states which will join the EU in 2004, Bulgaria and Romania which will probably join in 2007 as well as Turkey are analysed. Most of these countries have had a century-long tradition in the utilisation of RES, primarily in biomass and hydropower. However, the communist regimes were convinced of the superiority of large-scale systems and converted the energy sectors into centralised units. Due to this dominating belief system more decentralised applications such as installations using renewable energies had to close. One crucial driving force for future renewable energy development in the Accession States comes from the stipulations set by the EU. The EU-Directive on the promotion of electricity produced from RES gives the new EU-members targets for their RES-development until 2010. Due to the Directive many Accession States have already begun to pay more attention to the topic and to introduce more systematic policies. Six of the Accession States have introduced minimum tariffs which were one of the main success conditions (besides a stable and sound investment programme as well as favourable background conditions) in the leading wind energy countries Germany and Spain. Beside the external pressure by the EU and other international obligations other driving forces such as the path dependencies in the national energy policies (degree of coal, oil and gas exploitation, nuclear power use, import dependency), the political support schemes for renewable energies, possibilities of obtaining external financial support and the cognitive environment are discussed. Finally similarities and differences between EU-15 and Accession States are worked out

  18. Rydberg energies using excited state density functional theory

    International Nuclear Information System (INIS)

    Cheng, C.-L.; Wu Qin; Van Voorhis, Troy

    2008-01-01

    We utilize excited state density functional theory (eDFT) to study Rydberg states in atoms. We show both analytically and numerically that semilocal functionals can give quite reasonable Rydberg energies from eDFT, even in cases where time dependent density functional theory (TDDFT) fails catastrophically. We trace these findings to the fact that in eDFT the Kohn-Sham potential for each state is computed using the appropriate excited state density. Unlike the ground state potential, which typically falls off exponentially, the sequence of excited state potentials has a component that falls off polynomially with distance, leading to a Rydberg-type series. We also address the rigorous basis of eDFT for these systems. Perdew and Levy have shown using the constrained search formalism that every stationary density corresponds, in principle, to an exact stationary state of the full many-body Hamiltonian. In the present context, this means that the excited state DFT solutions are rigorous as long as they deliver the minimum noninteracting kinetic energy for the given density. We use optimized effective potential techniques to show that, in some cases, the eDFT Rydberg solutions appear to deliver the minimum kinetic energy because the associated density is not pure state v-representable. We thus find that eDFT plays a complementary role to constrained DFT: The former works only if the excited state density is not the ground state of some potential while the latter applies only when the density is a ground state density.

  19. Measuring energy efficiency in the United States` economy: A beginning

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-10-01

    Energy efficiency is a vital component of the Nation`s energy strategy. One of the Department of Energy`s missions are to promote energy efficiency to help the Nation manage its energy resources. The ability to define and measure energy efficiency is essential to this objective. In the absence of consistent defensible measures, energy efficiency is a vague, subjective concept that engenders directionless speculation and confusion rather than insightful analysis. The task of defining and measuring energy efficiency and creating statistical measures as descriptors is a daunting one. This publication is not a final product, but is EIA`s first attempt to define and measure energy efficiency in a systematic and robust manner for each of the sectors and the United States economy as a whole. In this process, EIA has relied on discussions, customer reviews, in-house reviews, and seminars that have focused on energy efficiency in each of the sectors. EIA solicits the continued participation of its customers in further refining this work.

  20. Energy drinks in the Gulf Cooperation Council states: A review.

    Science.gov (United States)

    Alhyas, Layla; El Kashef, Ahmed; AlGhaferi, Hamad

    2016-01-01

    Energy drinks have become a popular beverage worldwide. This review was carried out to have an overview among adolescents and emerging adults in the Gulf Co-operation Council states about energy drinks consumption rates and other related issues such as starting age and patterns of energy drink consumption. The Medline and Embase databases were searched separately using different terms such as energy drinks, energy beverages, and caffeinated drinks. Data related to the rates of energy drinks use were entered in STATA for statistical analysis. Then, these data were used to conduct meta-analysis to estimate the rate of energy drink consumption. Overall, meta-analysis results showed that the estimated rates of energy drinks consumption is 46.9% (95% CIs, 33.2 -66.1; nine studies) with I-square 3.7%. Findings indicated that individuals start to consume energy drinks at approximately 16 years old, and males were found to consume energy drinks more frequently than females. Results from this review carry several recommendations for policy and enforcement, public education and research that can help policy and decision makers to achieve the goal of safer use of energy drinks.

  1. Contribution of the New WORLDVIEW-2 Spectral Bands for Urban Mapping in Coastal Areas: Case Study SÃO LUÍS ( MARANHÃO State, Brazil)

    Science.gov (United States)

    Souza, U. D. V.; kux, H. J. H.

    2012-07-01

    The objective of this study is to verify the contribution of the spectral bands from the new WorldView-2 satellite for the extraction of urban targets aiming a detailed mapping from the city of São Luis, at the coastal zone of Maranhão State, Brazil. This satellite system has 3 bands in the visible portion of the spectrum and also the following 4 new bands: Coastal (400-450 nm), Yellow (585- 625 nm), Red Edge (705-745 nm), and Near Infrared 2 (860-1040 nm). As for the methodology used, initially a fusion was made among the panchromatic and the multispectral bands, combining the spectral information of the multispectral bands with the geometric information of the panchromatic band. Following the ortho-rectification of the dataset was done, using ground control points (GCPs) obtained during field survey. The classification reached high values of Kappa indices. The use of the new bands Red Edge and Near Infrared 2, allowed the improvement of discriminations at tidal flats, mangrove and other vegetation types. The Yellow band improved the discrimination of bare soils - very important information for urban planning - and ceramic roofs. The Coastal band allowed to map the tidal channels which cross the urban area of São Luis, a typical feature of this coastal area. The functionalities of software GEODMA used, allowed an efficient attribute selection which improved the land cover classification from the test sites. The new WorldView-2 bands permit the identification and extraction of the features mentioned, because these bands are positioned at important parts of the electromagnetic spectrum, such as band Red Edge, which strongly improves the discrimination of vegetation conditions. Combining both higher spatial and spectral resolutions, WorldView-2 data allows an improvement on the discrimination of physical characteristics of the targets of interest, thus permitting a higher precision of land use/land cover maps, contributing to urban planning. The test sites of this

  2. Collective and single-particle states at high excitation energy

    International Nuclear Information System (INIS)

    Van den Berg, A.M.; Van der Molen, H.K.T.; Harakeh, M.N.; Akimune, H.; Daito, I.; Fujimura, H.; Fujiwara, M.; Ihara, F.; Inomata, T.

    2000-01-01

    Complete text of publication follows. Damping of high-lying single-particle states was investigated by the study of proton decay from high-lying states in 91 Nb, populated by the 90 Zr(α,t) reaction with E α = 180 MeV. In addition to decay to the ground state of 90 Zr, semi-direct decay was observed to the low-lying (2 + and 3 - ) phonon states, confirming the conclusion from other experiments that these phonon states play an important role in the damping process of the single-particle states. Furthermore, the population and decay of Isobaric Analogue States of 91 Zr, which are located at an excitation energy of about 10 - 12 MeV in 91 Nb, has been studied in the same reaction. (author)

  3. Plasmon-modulated photoluminescence from gold nanostructures and its dependence on plasmon resonance, excitation energy, and band structure

    NARCIS (Netherlands)

    Le Thi Ngoc, Loan; Wiedemair, Justyna; van den Berg, Albert; Carlen, Edwin

    2015-01-01

    Two distinct single-photon plasmon-modulated photoluminescence processes are generated from nanostructured gold surfaces by tuning the spectral overlap of the incident laser source, localized surface plasmon resonance band, and the interband transitions between the d and sp bands, near the X-and

  4. United States and Spain sign energy R and D agreement

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    In two memoranda signed June 6, 1986, the United States Department of Energy and two Spanish governmental agencies have agreed to conduct cooperative energy research and development projects. These five-year bilateral agreements mark the first formal cooperative energy efforts between the two countries. Areas of cooperation in one memorandum between the DOE and the Spanish Junta de Energia Nuclear are as follows: nuclear energy (including nuclear safety technology), radioactive waste management, renewable energy (including biomass), and coal and gas technologies. The second memorandum, signed by the DOE and the Spanish Instituto Geologico y Minero, deals solely with coal gasification and geothermal energy technologies. No specific projects or development efforts are discussed in the memoranda. Rather, the terms for exchanges of personnel, technology conferences, establishment of projects, etc. are more to outline areas to possible future cooperation

  5. Structure and optical band-gap energies of Ba0.5Sr0.5TiO3 thin films fabricated by RF magnetron plasma sputtering

    International Nuclear Information System (INIS)

    Xu, Zhimou; Suzuki, Masato; Yokoyama, Shin

    2005-01-01

    The structure and optical band-gap energies of Ba 0.5 Sr 0.5 TiO 3 (BST0.5) thin films prepared on SiO 2 /Si and fused quartz substrates by RF magnetron plasma sputtering were studied in terms of deposition temperature and film thickness. Highly (100)-oriented BST0.5 thin films were successfully sputtered on a Si substrate with an approximately 1.0-μm-thick SiO 2 layer at a deposition temperature of above 450degC. The optical transmittance of BST0.5 thin films weakly depended on the magnitude of X-ray diffraction (XRD) peak intensity. This is very helpful for monolithic integration of BST0.5 films for electrooptical functions directly onto a SiO 2 /Si substrate. The band-gap energies showed a strong dependence on the deposition temperature and film thickness. It was mainly related to the quantum size effect and the influence of the crystallinity of thin films, such as grain boundaries, grain size, oriented growth, and the existence of an amorphous phase. The band-gap energy values, which were much larger than those of single crystals, decreased with the increase in the deposition temperature and the thickness of BST0.5 thin films. The band-gap energy of 311-nm-thick amorphous BST0.5 thin film was about 4.45 eV and that of (100)-oriented BST0.5 thin film with a thickness of 447 nm was about 3.89 eV. It is believed that the dependence of the band-gap energies of the thin films on the crystallinity for various values of deposition temperature and film thickness means that there could be application in integrated optical devices. (author)

  6. Study of Unwanted Emissions in the CENELEC-A Band Generated by Distributed Energy Resources and Their Influence over Narrow Band Power Line Communications

    Directory of Open Access Journals (Sweden)

    Noelia Uribe-Pérez

    2016-11-01

    Full Text Available Distributed Energy Resources might have a severe influence on Power Line Communications, as they can generate interfering signals and high frequency emissions or supraharmonics that may cause loss of metering and control data. In this paper, the influence of various energy resources on Narrowband Power Line Communications is described and analyzed through several test measurements performed in a real microgrid. Accordingly, the paper describes the effects on smart metering communications through the Medium Access Control (MAC layer analysis. Results show that the switching frequency of inverters and the presence of battery chargers are remarkable sources of disturbance in low voltage distribution networks. In this sense, the results presented can contribute to efforts towards standardization and normative of emissions at higher frequencies higher, such as CENELEC EN 50160 and IEC/TS 62749.

  7. Mitigation of near-band balanced steady-state free precession through-plane flow artifacts using partial dephasing.

    Science.gov (United States)

    Datta, Anjali; Cheng, Joseph Y; Hargreaves, Brian A; Baron, Corey A; Nishimura, Dwight G

    2018-06-01

    To mitigate artifacts from through-plane flow at the locations of steady-state stopbands in balanced steady-state free precession (SSFP) using partial dephasing. A 60° range in the phase accrual during a TR was created over the voxel by slightly unbalancing the slice-select dephaser. The spectral profiles of SSFP with partial dephasing for various constant flow rates and during pulsatile flow were simulated to determine if partial dephasing decreases through-plane flow artifacts originating near SSFP dark bands while maintaining on-resonant signal. Simulations were then validated in a flow phantom. Lastly, phase-cycled SSFP cardiac cine images were acquired with and without partial dephasing in six subjects. Partial dephasing decreased the strength and non-linearity of the dependence of the signal at the stopbands on the through-plane flow rate. It thus mitigated hyper-enhancement from out-of-slice signal contributions and transient-related artifacts caused by variable flow both in the phantom and in vivo. In six volunteers, partial dephasing noticeably decreased artifacts in all of the phase-cycled cardiac cine datasets. Partial dephasing can mitigate the flow artifacts seen at the stopbands in balanced SSFP while maintaining the sequence's desired signal. By mitigating hyper-enhancement and transient-related artifacts originating from the stopbands, partial dephasing facilitates robust multiple-acquisition phase-cycled SSFP in the heart. Magn Reson Med 79:2944-2953, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  8. State Energy Efficiency Resource Standards: Design, Status, and Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, D.; Zinaman, O.

    2014-05-01

    An energy efficiency resource standard (EERS) is a policy that requires utilities or other entities to achieve a specified amount of energy savings through customer energy efficiency programs within a specified timeframe. EERSs may apply to electricity usage, natural gas usage, or both. This paper provides an overview of the key design features of EERSs for electricity, reviews the variation in design of EERSs across states, and provides an estimate of the amount of savings required by currently specified EERSs in each state. As of December, 2013, 23 states have active and binding EERSs for electricity. We estimate that state EERSs will require annual electricity savings of approximately 8-11% of total projected demand by 2020 in states with EERSs, however the level of savings targeted by the policies varies significantly across states. In addition to the variation in targeted savings, the design of EERSs varies significantly across states leading to differences in the suite of incentives created by the policy, the flexibility of compliance with the policy, the balance of benefits and costs of the policy between producers and consumers, and the certainty with which the policy will drive long-term savings.

  9. Energy use in Minnesota state-owned facilities

    Energy Technology Data Exchange (ETDEWEB)

    Hirst, E; Eastes, C; Tyler, R

    1981-08-01

    This paper describes and analyzes the contents of a large data base containing infomation on monthly energy use of state-owned facilities in Minnesota are described and analyzed. The data base includes information on 42 community colleges, state universities, hospitals, prisons, and the St. Paul Capitol Complex. The data span a seven year period (1972 - 1978) and include about 3,500 observations. Several data base management issues are discussed. These include errors and their correction, development of simple and consistent definitions for key terms, and collection of information on key determinants of energy use at these facilities. Regression equations were developed to predict monthly heating fuel use and total energy use. These equations show that more than 60% of the variation in energy use per unit floorspace can be explained by a few variables.

  10. The Seismic Broad Band Western Mediterranean (wm) Network and the Obs Fomar Pool: Current state and Obs activities.

    Science.gov (United States)

    Pazos, Antonio; Davila, Jose Martin; Buforn, Elisa; Bezzeghoud, Mourad; Harnafi, Mimoun; Mattesini, Mauricio; Caldeira, Bento; Hanka, Winfried; El Moudnib, Lahcen; Strollo, Angelo; Roca, Antoni; Lopez de Mesa, Mireya; Dahm, Torsten; Cabieces, Roberto

    2016-04-01

    The Western Mediterranean (WM) seismic network started in 1996 as an initiative of the Royal Spanish Navy Observatory (ROA) and the Universidad Complutense de Madrid (UCM), with the collaboration of the GeoForschungsZentrum (GFZ) of Potsdam. A first broad band seismic station (SFUC) was installed close to Cádiz (South Spain). Since then, additional stations have been installed in the Ibero-Moghrebian region. In 2005, the "WM" code was assigned by the FDSN and new partners were jointed: Evora University (UEVO, Portugal), the Scientifique Institute of Rabat (ISRABAT, Morocco), and GFZ. Now days, the WM network is composed by 15 BB stations, all of them with Streckaisen STS-2 or STS-2.5 sensors, Quanterra or Earthdata digitizers and SeiscomP. Most them have co-installed a permanent geodetic GPS stations, and some them also have an accelerometer. There are 10 stations deployed in Spanish territory (5 in the Iberian peninsula, 1 in Balearic islands and 4 in North Africa Spanish places) with VSAT or Internet communications, 2 in Portugal (one of them without real time), and 3 in Morocco (2 VSAT and 1 ADSL). Additionally, 2 more stations (one in South Spain and one in Morocco) will be installed along this year. Additionally ROA has deployed a permanent real time VBB (CMG-3T: 360s) station at the Alboran Island. Due to the fact that part of the seismic activity is located at marine areas, and also because of the poor geographic azimuthal coverage at some zones provided by the land stations (specially in the SW of the San Vicente Cape area), ROA and UCM have acquired six broad band "LOBSTERN" OBS, manufactured by KUM (Kiel, Germany), conforming the OBS FOMAR pool. Three of them with CMG-40T sensor and the other with Trillium 120. These OBS were deployed along the Gibraltar strait since January to November 2014 to study the microseismicity in the Gibraltar strait area. In September 2015 FOMAR network has been deployed in SW of the San Vicente Cape for 8 months as a part of

  11. Reaction mechanism of a PbS-on-ZnO heterostructure and enhanced photovoltaic diode performance with an interface-modulated heterojunction energy band structure.

    Science.gov (United States)

    Li, Haili; Jiao, Shujie; Ren, Jinxian; Li, Hongtao; Gao, Shiyong; Wang, Jinzhong; Wang, Dongbo; Yu, Qingjiang; Zhang, Yong; Li, Lin

    2016-02-07

    A room temperature successive ionic layer adsorption and reaction (SILAR) method is introduced for fabricating quantum dots-on-wide bandgap semiconductors. Detailed exploration of how SILAR begins and proceeds is performed by analyzing changes in the electronic structure of related elements at interfaces by X-ray photoelectric spectroscopy, together with characterization of optical properties and X-ray diffraction. The distribution of PbS QDs on ZnO, which is critical for optoelectrical applications of PbS with a large dielectric constant, shows a close relationship with the dipping order. A successively deposited PbS QDs layer is obtained when the sample is first immersed in Na2S solution. This is reasonable because the initial formation of different chemical bonds on ZnO nanorods is closely related to dangling bonds and defect states on surfaces. Most importantly, dipping order also affects their optoelectrical characteristics greatly, which can be explained by the heterojunction energy band structure related to the interface. The formation mechanism for PbS QDs on ZnO is confirmed by the fact that the photovoltaic diode device performance is closely related to the dipping order. Our atomic-scale understanding emphasises the fundamental role of surface chemistry in the structure and tuning of optoelectrical properties, and consequently in devices.

  12. Free energy surfaces in the superconducting mixed state

    Science.gov (United States)

    Finnemore, D. K.; Fang, M. M.; Bansal, N. P.; Farrell, D. E.

    1989-01-01

    The free energy surface for Tl2Ba2Ca2Cu3O1O has been measured as a function of temperature and magnetic field to determine the fundamental thermodynamic properties of the mixed state. The change in free energy, G(H)-G(O), is found to be linear in temperature over a wide range indicating that the specific heat is independent of field.

  13. Fullerene-Free Organic Solar Cells with an Efficiency of 10.2% and an Energy Loss of 0.59 eV Based on a Thieno[3,4-c]Pyrrole-4,6-dione-Containing Wide Band Gap Polymer Donor.

    Science.gov (United States)

    Hadmojo, Wisnu Tantyo; Wibowo, Febrian Tri Adhi; Ryu, Du Yeol; Jung, In Hwan; Jang, Sung-Yeon

    2017-09-27

    Although the combination of wide band gap polymer donors and narrow band gap small-molecule acceptors achieved state-of-the-art performance as bulk heterojunction (BHJ) active layers for organic solar cells, there have been only several of the wide band gap polymers that actually realized high-efficiency devices over >10%. Herein, we developed high-efficiency, low-energy-loss fullerene-free organic solar cells using a weakly crystalline wide band gap polymer donor, PBDTTPD-HT, and a nonfullerene small-molecule acceptor, ITIC. The excessive intermolecular stacking of ITIC is efficiently suppressed by the miscibility with PBDTTPD-HT, which led to a well-balanced nanomorphology in the PBDTTPD-HT/ITIC BHJ active films. The favorable optical, electronic, and energetic properties of PBDTTPD-HT with respect to ITIC achieved panchromatic photon-to-current conversion with a remarkably low energy loss (0.59 eV).

  14. Molecular states of HeH+. Energies and dynamical couplings

    International Nuclear Information System (INIS)

    Macias, A.; Riera, A.; Yanez, M.

    1983-01-01

    We complete the molecular results reported in a previous paper by presenting additional energies (for /sup 1,3/μ states) and radial couplings (between 'μ states) of the HeH + system. These results are needed to treat elastic and inelastic charge-exchange processes when full account is taken of momentum-transfer problems. We also present a formalism to calculate radial couplings between wave functions computed with the use of different variational methods and basis sets. The detailed form of the radial couplings is discussed and related to the Barat-Lichten correlation diagram. The effect of using finite basis sets in calculatig degenerate molecular energies is also discussed

  15. Framework for State-Level Renewable Energy Market Potential Studies

    Energy Technology Data Exchange (ETDEWEB)

    Kreycik, C.; Vimmerstedt, L.; Doris, E.

    2010-01-01

    State-level policymakers are relying on estimates of the market potential for renewable energy resources as they set goals and develop policies to accelerate the development of these resources. Therefore, accuracy of such estimates should be understood and possibly improved to appropriately support these decisions. This document provides a framework and next steps for state officials who require estimates of renewable energy market potential. The report gives insight into how to conduct a market potential study, including what supporting data are needed and what types of assumptions need to be made. The report distinguishes between goal-oriented studies and other types of studies, and explains the benefits of each.

  16. Energy dependence of critical state of single-component systems

    International Nuclear Information System (INIS)

    Volchenkova, R.A.

    1985-01-01

    Equations of critical states of the single-component systems: Psub(cr)(/Psub(o)=(Tsub(cr)/Tsub(o))x0.73, Tsub(cr)=K(Tsub(boil))sup(1.116) and Hsub(cr)(/Hsub(B)=Tsub(sr)/Tsub(B))sup(1.48) where Tsub(B)=1K, Hsub(B)-2 kcal/g-at, K-dimension factor are presented. It is shown that the revealed dependence Hsub(cr)=H(Tsub(cr)) is an energy boundary of a liquid-vapour phase state of the single-component systems beyond limits of which difference between liquid and vapour phases vanishes in increasing the system energy content. The given equations of state are true for all the single-component systems and permit to consider physicomechanical properties of substances in dynamic state depending on external conditions. Critical temperatures and dependences for elements from the most fusible He to infusible W and Re have been calculated

  17. Properties of states of low energy on cosmological spacetimes

    International Nuclear Information System (INIS)

    Degner, Andreas

    2013-01-01

    The present thesis investigates properties of a class of physical states of the quantised scalar field in FRW spacetimes, namely the states of low energy (SLE's). These states are characterised by minimising the time-smeared energy density measured by an isotropic observer, where the smearing is performed with respect to a test function f of compact support. Furthermore, they share all spatial symmetries of the spacetime. Since SLE's are Hadamard states, expectations values of observables like the energy density can be rigorously defined via the so called point-splitting method. In a first step, this procedure is applied to the explicit calculation of the energy density in SLE's for the case of de Sitter space with flat spatial sections. In particular, the e ect of the choice of the mass m and the test function f is discussed. The obtained results motivate the question whether SLE's converge to a distinguished state (namely the Bunch Davies state) when the support of f is shifted to the infinite past. It is shown that this is indeed the case, even in the more general class of asymptotic de Sitter spacetimes, where an analogon of the Bunch Davies state can be defined. This result enables the interpretation of such distinguished states to be SLE's in the infinite past, independently of the form of the smearing function f. Finally, the role of SLE's for the semiclassical backreaction problem is discussed. We derive the semiclassical Friedmann equation in a perturbative approach over Minkowski space. This equation allows for a stability analysis of Minkowski space by the investigation of asymptotic properties of solutions. We also treat this problem using a numerical method.

  18. Bedside Monitoring of Cerebral Energy State During Cardiac Surgery

    DEFF Research Database (Denmark)

    Mölström, Simon; Nielsen, Troels H; Andersen, Claus

    2017-01-01

    OBJECTIVES: This study investigated whether the lactate-to-pyruvate (LP) ratio obtained by microdialysis (MD) of the cerebral venous outflow reflected a derangement of global cerebral energy state during cardiopulmonary bypass (CPB). DESIGN: Interventional, prospective, randomized study. SETTING...... in either group during CPB. In each group, 50% of the patients showed significant cognitive decline (mini-mental state examination, 3 points) 2 days after surgery. CONCLUSION: The LP ratio of cerebral venous blood increased significantly during CPB, indicating compromised cerebral oxidative metabolism...

  19. Properties of states of low energy on cosmological spacetimes

    Energy Technology Data Exchange (ETDEWEB)

    Degner, Andreas

    2013-01-15

    The present thesis investigates properties of a class of physical states of the quantised scalar field in FRW spacetimes, namely the states of low energy (SLE's). These states are characterised by minimising the time-smeared energy density measured by an isotropic observer, where the smearing is performed with respect to a test function f of compact support. Furthermore, they share all spatial symmetries of the spacetime. Since SLE's are Hadamard states, expectations values of observables like the energy density can be rigorously defined via the so called point-splitting method. In a first step, this procedure is applied to the explicit calculation of the energy density in SLE's for the case of de Sitter space with flat spatial sections. In particular, the e ect of the choice of the mass m and the test function f is discussed. The obtained results motivate the question whether SLE's converge to a distinguished state (namely the Bunch Davies state) when the support of f is shifted to the infinite past. It is shown that this is indeed the case, even in the more general class of asymptotic de Sitter spacetimes, where an analogon of the Bunch Davies state can be defined. This result enables the interpretation of such distinguished states to be SLE's in the infinite past, independently of the form of the smearing function f. Finally, the role of SLE's for the semiclassical backreaction problem is discussed. We derive the semiclassical Friedmann equation in a perturbative approach over Minkowski space. This equation allows for a stability analysis of Minkowski space by the investigation of asymptotic properties of solutions. We also treat this problem using a numerical method.

  20. Clean energy funds: An overview of state support for renewable energy

    Energy Technology Data Exchange (ETDEWEB)

    Bolinger, Mark; Wiser, Ryan

    2001-04-01

    Across the United States, as competition in the supply and delivery of electricity has been introduced, states have sought to ensure the continuation of ''public benefits'' programs traditionally administered or funded by electric utilities. Many states have built into their restructuring plans methods of supporting renewable energy sources. One of the most popular policy mechanisms for ensuring such continued support has been the system-benefits charge (SBC), a non-bypassable charge to electricity customers (usually applied on a cents/kWh basis) used to collect funds for public purpose programs. Thus far, at least fourteen states have established SBC funds targeted in part towards renewable energy. This paper discusses the status and performance of these state renewable or ''clean'' energy funds supported by system-benefits charges. As illustrated later, existing state renewable energy funds are expected to collect roughly $3.5 billion through 2012 for renewable energy. Clearly, these funds have the potential to provide significant support for clean energy technologies over at least the next decade. Because the level of funding for renewable energy available under these programs is unprecedented and because fund administrators are developing innovative and new programs to fund renewable projects, a certain number of program failures are unavoidable. Also evident is that states are taking very different approaches to the distribution of these funds and that many lessons are being learned as programs are designed, implemented, and evaluated. Our purpose in this paper is therefore to relay early experience with these funds and provide preliminary lessons learned from that experience. It is our hope that this analysis will facilitate learning across states and help state fund managers develop more effective and more coordinated programs. Central to this paper are case studies that provide information on the SBC-funded renewable

  1. Energy policy, aid, and the development of renewable energy resources in Small Island Developing States

    International Nuclear Information System (INIS)

    Dornan, Matthew; Shah, Kalim U.

    2016-01-01

    Small Island Developing States (SIDS) have established ambitious renewable energy targets. The promotion of renewable energy has been motivated by several factors: a desire to lessen dependence on fossil fuels, to attract development assistance in the energy sector, and to strengthen the position of SIDS in climate change negotiations. Here we explore the interplay between the role of aid and energy policy in the development of renewable energy resources in SIDS. We find that the importance of development assistance has implications for the sustainability of renewable energy development, given that funding is not always accompanied by necessary energy policy reforms. We also identify energy efficiency and access to modern energy services as having received insufficient attention in the establishment and structure of renewable energy targets in SIDS, and argue that this is problematic due to the strong economic case for such investments. - Highlights: • SIDS have established the world's most ambitious renewable energy targets. • These are motivated by fossil fuel dependence and climate change vulnerability. • Aid dependence has influenced the ambition of renewable energy targets. • Energy efficiency and energy access have received insufficient attention. • Domestic policy reforms necessary for the achievement of targets has been limited.

  2. Tuning the energy band gap of ternary alloyed Cd1-xPbxS quantum dots for photovoltaic applications

    Science.gov (United States)

    Badawi, Ali

    2016-02-01

    Tuning the energy band gap of ternary alloyed Cd1-xPbxS (x: 0, 0.33, 0.5, 0.67 and 1) quantum dots (QDs) for photovoltaic applications is studied. Alloyed Cd1-xPbxS QDs were adsorbed onto TiO2 nanoparticles (NPs) using ssuccessive ionic layer adsorption and reaction (SILAR) methode. EDX measurements ensure the success adsorption of alloyed Cd1-xPbxS QDs onto the TiO2 electrode. At 100 mW/cm2 (AM 1.5) sun illumination, the photovoltaic performance of alloyed Cd1-xPbxS QDs sensitized solar cells (QDSSCs) was measured. The maximum values of Jsc (1.92 mA/cm2) and η (0.36%) for the alloyed Cd1-xPbxS QDSSCs were obtained when the molar ratio of Cd/Pb is 0.33/0.67. the open circuit voltage (Voc) is equal 0.61 ± 0.01 V for all alloyed Cd1-xPbxS QDSSCs. The electron back recombination rates decrease considerably for alloyed Cd1-xPbxS QDSSCs as x value increases, peaking at 0.67. The electron lifetime (τ) for Cd0.33Pb0.67S QDSSCs is one order of magnitude larger than that of the other alloyed Cd1-xPbxS QDSSCs with different x value. Under ON-OFF cycles to solar illumination, the open circuit voltage decay measurements show the high sensitivity and reproducibility of alloyed Cd1-xPbxS QDSSCs.

  3. Excitation of the 4.3-μm bands of CO2 by low-energy electrons

    International Nuclear Information System (INIS)

    Bulos, R.R.; Phelps, A.V.

    1976-01-01

    Rate coefficients for the excitation of the 4.3-μm bands of CO 2 by low-energy electrons in CO 2 have been measured using a drift-tube technique. The CO 2 density [(1.5 to 7) x 10 17 molecules/cm 3 ] was chosen to maximize the radiation reaching the detector. Line-by-line transmission calculations were used to take into account the absorption of 4.3-μm radiation. A small fraction of the approximately 10 -8 W of the 4.3-μm radiation produced by the approximately 10 -7 -A electron current was incident on an InSb photovoltaic detector. The detector calibration and absorption calculations were checked by measuring the readily calculated excitation coefficients for vibrational excitation of N 2 containing a small concentration of CO 2 . For pure CO 2 the number of molecules capable of emitting 4.3-μm radiation produced per cm of electron drift and per CO 2 molecule varied from 10 -17 cm -2 at E/N = 6 x 10 -17 V cm 2 to 5.4 x 10 -16 cm -2 at E/N = 4 x 10 -16 V cm 2 . Here E is the electric field and N is total gas density. The excitation coefficients at lower E/N are much larger than estimated previously. A set of vibrational excitation cross sections is obtained for CO 2 which is consistent with the excitation coefficient data and with most of the published electron-beam data

  4. Disaggregate energy consumption and industrial output in the United States

    International Nuclear Information System (INIS)

    Ewing, Bradley T.; Sari, Ramazan; Soytas, Ugur

    2007-01-01

    This paper investigates the effect of disaggregate energy consumption on industrial output in the United States. Most of the related research utilizes aggregate data which may not indicate the relative strength or explanatory power of various energy inputs on output. We use monthly data and employ the generalized variance decomposition approach to assess the relative impacts of energy and employment on real output. Our results suggest that unexpected shocks to coal, natural gas and fossil fuel energy sources have the highest impacts on the variation of output, while several renewable sources exhibit considerable explanatory power as well. However, none of the energy sources explain more of the forecast error variance of industrial output than employment

  5. Mastery of energy in the French State buildings

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1996-06-01

    One of the goals of the ADEME (the French Environment and Mastery of Energy Agency) is to improve the energy efficiency of buildings and of their equipments. Public and State buildings represent an important source of energy saving possibilities concerning the heating, the lighting and the air-conditioning. Total buildings energy consumption reached 86.3 Mtep in 1994 (45.2% of the total French energy consumption). State buildings represent only a 2.2 Mtep consumption per year for a heated surface of 65 millions of m{sup 2}. Heating represents 60% of this consumption. The corresponding functioning expenses are estimated to 3 billions of French Francs from which about 500 MF could be saved using more performing equipments and materials. In 1991, the French Ministry of Law in collaboration with the ADEME, carried out an action plan of energy audits for the mastery of energy in the French Law Courts. This action led to a 2.3 MF saving per year, from which 2.3 MF are gained without investments and 1.4 MF are linked to modernization works. Financing can be done by taking a 10 years credit-lease with refunding annuities lower than the saving generated by the investment. (J.S.). 1 ref., 1 photo.

  6. BUILDING STRONGER STATE ENERGY PARTNERSHIPS WITH THE U.S. DEPARTMENT OF ENERGY

    Energy Technology Data Exchange (ETDEWEB)

    Kate Burke

    2002-11-01

    This technical progress report includes an update of the progress during the second year of cooperative agreement DE-FC26-00NT40802, Building Stronger State Energy Partnerships with the U.S. Department of Energy. The report also describes the barriers in conduct of the effort, and our assessment of future progress and activities.

  7. Competition within the energy sector and State regulation

    International Nuclear Information System (INIS)

    Larsen, A.; Jess Olsen, O.

    1995-10-01

    It is presumed that energy markets will be liberalized. Questions discussed are how the Danish electricity and gas sectors are to be re-regulated in order to ensure that this goal is reached in the most satisfactory manner (cheaper energy supply under competitive conditions) and whether there will be a conflict between the goal of liberalization and the environmental goals of clean technology and energy conservation. It is suggested that a compulsory splitting up of the two regional power associations in Denmark should not be necessary. Transmission and distribution must continue to be regulated as these are natural monopolies not compatible with competition. District heating will still be a monopoly and its prices must be closely regulated to prevent soaring. The opening up of the European gas market to competition will threaten Danish energy utilities. The increasing compulsory use of natural gas in cogeneration plants to politically determined high prices is not sustainable under competitive conditions. Energy saving activities should not be affected. Energy surcharges are attractive measures on a liberalized market. The regulation of competition ought to be incorporated explicitly as a restriction in the Ministry of Energy's energy policy regulation. Energy utilities could be excluded from participation in price setting. International regulation of competition will demand a clarification of the separation of regulatory competence between the member states and the European Commission. It will also be necessary to adjust the Danish regulation of the electricity sector to the future Scandinavian system. (AB) 77 refs

  8. Multi-shell spherical GaAs /AlxGa1-x As quantum dot shells-size distribution as a mechanism to generate intermediate band energy levels

    Science.gov (United States)

    Rodríguez-Magdaleno, K. A.; Pérez-Álvarez, R.; Martínez-Orozco, J. C.; Pernas-Salomón, R.

    2017-04-01

    In this work the generation of an intermediate band of energy levels from multi-shell spherical GaAs /AlxGa1-x As quantum dot shells-size distribution is reported. Within the effective mass approximation the electronic structure of a GaAs spherical quantum-dot surrounded by one, two and three shells is studied in detail using a numerically stable transfer matrix method. We found that a shells-size distribution characterized by continuously wider GaAs domains is a suitable mechanism to generate the intermediate band whose width is also dependent on the Aluminium concentration x. Our results suggest that this effective mechanism can be used for the design of wider intermediate band than reported in other quantum systems with possible solar cells enhanced performance.

  9. Effective dark energy equation of state in interacting dark energy models

    Energy Technology Data Exchange (ETDEWEB)

    Avelino, P.P., E-mail: ppavelin@fc.up.pt [Centro de Astrofisica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Departamento de Fisica e Astronomia da Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Silva, H.M.R. da, E-mail: hilberto.silva@gmail.com [Departamento de Fisica e Astronomia da Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2012-07-24

    In models where dark matter and dark energy interact non-minimally, the total amount of matter in a fixed comoving volume may vary from the time of recombination to the present time due to energy transfer between the two components. This implies that, in interacting dark energy models, the fractional matter density estimated using the cosmic microwave background assuming no interaction between dark matter and dark energy will in general be shifted with respect to its true value. This may result in an incorrect determination of the equation of state of dark energy if the interaction between dark matter and dark energy is not properly accounted for, even if the evolution of the Hubble parameter as a function of redshift is known with arbitrary precision. In this Letter we find an exact expression, as well as a simple analytical approximation, for the evolution of the effective equation of state of dark energy, assuming that the energy transfer rate between dark matter and dark energy is described by a simple two-parameter model. We also provide analytical examples where non-phantom interacting dark energy models mimic the background evolution and primary cosmic microwave background anisotropies of phantom dark energy models.

  10. Effective dark energy equation of state in interacting dark energy models

    International Nuclear Information System (INIS)

    Avelino, P.P.; Silva, H.M.R. da

    2012-01-01

    In models where dark matter and dark energy interact non-minimally, the total amount of matter in a fixed comoving volume may vary from the time of recombination to the present time due to energy transfer between the two components. This implies that, in interacting dark energy models, the fractional matter density estimated using the cosmic microwave background assuming no interaction between dark matter and dark energy will in general be shifted with respect to its true value. This may result in an incorrect determination of the equation of state of dark energy if the interaction between dark matter and dark energy is not properly accounted for, even if the evolution of the Hubble parameter as a function of redshift is known with arbitrary precision. In this Letter we find an exact expression, as well as a simple analytical approximation, for the evolution of the effective equation of state of dark energy, assuming that the energy transfer rate between dark matter and dark energy is described by a simple two-parameter model. We also provide analytical examples where non-phantom interacting dark energy models mimic the background evolution and primary cosmic microwave background anisotropies of phantom dark energy models.

  11. Novel methods for estimating lithium-ion battery state of energy and maximum available energy

    International Nuclear Information System (INIS)

    Zheng, Linfeng; Zhu, Jianguo; Wang, Guoxiu; He, Tingting; Wei, Yiying

    2016-01-01

    Highlights: • Study on temperature, current, aging dependencies of maximum available energy. • Study on the various factors dependencies of relationships between SOE and SOC. • A quantitative relationship between SOE and SOC is proposed for SOE estimation. • Estimate maximum available energy by means of moving-window energy-integral. • The robustness and feasibility of the proposed approaches are systematic evaluated. - Abstract: The battery state of energy (SOE) allows a direct determination of the ratio between the remaining and maximum available energy of a battery, which is critical for energy optimization and management in energy storage systems. In this paper, the ambient temperature, battery discharge/charge current rate and cell aging level dependencies of battery maximum available energy and SOE are comprehensively analyzed. An explicit quantitative relationship between SOE and state of charge (SOC) for LiMn_2O_4 battery cells is proposed for SOE estimation, and a moving-window energy-integral technique is incorporated to estimate battery maximum available energy. Experimental results show that the proposed approaches can estimate battery maximum available energy and SOE with high precision. The robustness of the proposed approaches against various operation conditions and cell aging levels is systematically evaluated.

  12. Monitoring of the state of the paper machine circulation water with a wide-band impedance measurement; Paperikoneen kiertoveden tilan seuranta laajakaistaisella impedanssimittauksella - MPKT 02

    Energy Technology Data Exchange (ETDEWEB)

    Varpula, T [VTT Automation, Espoo (Finland). Measurement Technology

    1999-12-31

    A new measurement method for monitoring the chemical state of the circulation water in the paper machine is proposed and studied. In the method, the electrical properties - conductivity and permittivity - of the water are measured in a wide frequency band: 20 Hz - 10 mhz. Large-molecule organic compounds in the water are expected cause characteristic changes in the dielectric properties of the water. Continuous monitoring of the permittivity in the wide frequency band thus reveals their presence. Various electronic measurement setups for the measurement are constructed and studied by using test samples. If the method turns out to be promising, a prototype device will be made. (orig.)

  13. Monitoring of the state of the paper machine circulation water with a wide-band impedance measurement; Paperikoneen kiertoveden tilan seuranta laajakaistaisella impedanssimittauksella - MPKT 02

    Energy Technology Data Exchange (ETDEWEB)

    Varpula, T. [VTT Automation, Espoo (Finland). Measurement Technology

    1998-12-31

    A new measurement method for monitoring the chemical state of the circulation water in the paper machine is proposed and studied. In the method, the electrical properties - conductivity and permittivity - of the water are measured in a wide frequency band: 20 Hz - 10 mhz. Large-molecule organic compounds in the water are expected cause characteristic changes in the dielectric properties of the water. Continuous monitoring of the permittivity in the wide frequency band thus reveals their presence. Various electronic measurement setups for the measurement are constructed and studied by using test samples. If the method turns out to be promising, a prototype device will be made. (orig.)

  14. Sea-ice deformation state from synthetic aperture radar imagery - Part I: comparison of C- and L-band and different polarization

    DEFF Research Database (Denmark)

    Dierking, Wolfgang; Dall, Jørgen

    2007-01-01

    configuration and ice conditions. Optical imagery of sufficient quality for comparison is available only in a very few cases. To characterize the deformation state, the areal fraction of deformation features and the average distance between these features are evaluated. The values obtained for both parameters...... negligible. In comparison to optical images, it was observed that deformed-ice areas can be distinguished from level ice over their whole length and extension at L-band, whereas at C-band, often, only prominent parts are visible....

  15. Early Changes in Alpha Band Power and DMN BOLD Activity in Alzheimer’s Disease: A Simultaneous Resting State EEG-fMRI Study

    Directory of Open Access Journals (Sweden)

    Katharina Brueggen

    2017-10-01

    Full Text Available Simultaneous resting state functional magnetic resonance imaging (rsfMRI–resting state electroencephalography (rsEEG studies in healthy adults showed robust positive associations of signal power in the alpha band with BOLD signal in the thalamus, and more heterogeneous associations in cortical default mode network (DMN regions. Negative associations were found in occipital regions. In Alzheimer’s disease (AD, rsfMRI studies revealed a disruption of the DMN, while rsEEG studies consistently reported a reduced power within the alpha band. The present study is the first to employ simultaneous rsfMRI-rsEEG in an AD sample, investigating the association of alpha band power and BOLD signal, compared to healthy controls (HC. We hypothesized to find reduced positive associations in DMN regions and reduced negative associations in occipital regions in the AD group. Simultaneous resting state fMRI–EEG was recorded in 14 patients with mild AD and 14 HC, matched for age and gender. Power within the EEG alpha band (8–12 Hz, 8–10 Hz, and 10–12 Hz was computed from occipital electrodes and served as regressor in voxel-wise linear regression analyses, to assess the association with the BOLD signal. Compared to HC, the AD group showed significantly decreased positive associations between BOLD signal and occipital alpha band power in clusters in the superior, middle and inferior frontal cortex, inferior temporal lobe and thalamus (p < 0.01, uncorr., cluster size ≥ 50 voxels. This group effect was more pronounced in the upper alpha sub-band, compared to the lower alpha sub-band. Notably, we observed a high inter-individual heterogeneity. Negative associations were only reduced in the lower alpha range in the hippocampus, putamen and cerebellum. The present study gives first insights into the relationship of resting-state EEG and fMRI characteristics in an AD sample. The results suggest that positive associations between alpha band power and BOLD

  16. Energy transfer from an alkene triplet state during pulse radiolysis

    International Nuclear Information System (INIS)

    Barwise, A.J.G.; Gorman, A.A.; Rodgers, M.A.J.

    1976-01-01

    Pulse radiolysis of a benzene solution of norbornene containing low concentrations of anthracene results in delayed formation of anthracene triplet: this is the result of diffusion-controlled energy transfer from the alkene triplet state which has a natural lifetime in benzene of 250 ns. The use of various hydrocarbon acceptors has indicated that Esub(T)=20 000+-500 cm -1 for the relaxed T 1 state of the alkene, at least 5000 cm -1 below that of the spectroscopic state. (Auth.)

  17. Identical and shifted identical bands

    International Nuclear Information System (INIS)

    Dodder, R.S; Jones, E.F.; Hamilton, J.H.

    1997-01-01

    Spontaneous fission of 252 Cm was studied with 72 large Compton suppressed Ge detectors in Gamma sphere. New isotopes 160 Sm and 162 Gd were identified. Through X-ray-γ and γ-γ-γ) coincidence measurements, level energies were established to spins 14 + to 20 + in 152 , 154 156 60 Nd 92 94 96 , 156 , 158 , 160 62 Sm 94 , 96 , 98 , and 160 , 162 64 Gd 96 , 98 . These nuclei exhibit a remarkable variety of identical bands and bands where the energies and moments of inertia are shifted by the same constant amount for every spin state from 2 + to 12 + for various combinations of nuclei differing by 2n, 4n, 2p, 4p, and α

  18. Formulation of thermodynamics for the glassy state : Configurational energy as a modest source of energy

    NARCIS (Netherlands)

    Nieuwenhuizen, T.M.

    2001-01-01

    Glass is an under-cooled liquid that very slowly relaxes towards the equilibrium crystalline state. Its energy balance is ill understood, since it is widely believed that the glassy state cannot be described thermodynamically. However, the classical paradoxes involving the Ehrenfest relations and

  19. Nanoscale probing of bandgap states on oxide particles using electron energy-loss spectroscopy.

    Science.gov (United States)

    Liu, Qianlang; March, Katia; Crozier, Peter A

    2017-07-01

    Surface and near-surface electronic states were probed with nanometer spatial resolution in MgO and TiO 2 anatase nanoparticles using ultra-high energy resolution electron energy-loss spectroscopy (EELS) coupled to a scanning transmission electron microscope (STEM). This combination allows the surface electronic structure determined with spectroscopy to be correlated with nanoparticle size, morphology, facet etc. By acquiring the spectra in aloof beam mode, radiation damage to the surface can be significantly reduced while maintaining the nanometer spatial resolution. MgO and TiO 2 showed very different bandgap features associated with the surface/sub-surface layer of the nanoparticles. Spectral simulations based on dielectric theory and density of states models showed that a plateau feature found in the pre-bandgap region in the spectra from (100) surfaces of 60nm MgO nanocubes is consistent with a thin hydroxide surface layer. The spectroscopy shows that this hydroxide species gives rise to a broad filled surface state at 1.1eV above the MgO valence band. At the surfaces of TiO 2 nanoparticles, pronounced peaks were observed in the bandgap region, which could not be well fitted to defect states. In this case, the high refractive index and large particle size may make Cherenkov or guided light modes the likely causes of the peaks. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Ba2+ Doped CH3NH3PbI3 to Tune the Energy State and Improve the Performance of Perovskite Solar Cells

    International Nuclear Information System (INIS)

    Zhang, Hanbing; Shang, Ming-hui; Zheng, Xiaoying; Zeng, Zhaobing; Chen, Renjie; Zhang, Ying; Zhang, Jing; Zhu, Yuejin

    2017-01-01

    Highlights: •Ba doping enlarges the energy band gap of MAPb 1-x Ba x I 3 . •Voc and Jsc are enhanced in perovskite solar cells. •DFT calculation proves the experiment results. -- Abstract: Elements substitution and doping in perovskite CH 3 NH 3 PbI 3 exhibit versatile tunability of energy band structure and opto-electric properties. Ba 2+ is chosen to substitute Pb 2+ for its similar valence state and ionic radius with Pb 2+ . Ba 2+ doping in perovskite (mol% <5) slightly enlarges the optic energy gap by conduction band minimum(CBM) upshifting to vacuum energy level, which is due to the smaller electronegativity of Ba than Pb. The enlarged band gap is also verified by density function theory calculations. In n-i-p structure perovskite solar cells (PSCs), because of the higher CBM of doped perovskite, the Fermi energy difference between n and p side is enlarged and the electron injection from the perovskite to TiO 2 is improved. Thus, both the photovoltage and photocurrent are improved by small amount Ba 2+ doping, resulting optimized 17.4% efficiency under AM1.5. This work reveals the relationship between the doping element property and the energy band structure of the perovskite, and highlights the doping method to improve the performance of PSCs.