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Sample records for pairing energy density

  1. Effects of pairing correlation on nuclear level density parameter and nucleon separation energy

    International Nuclear Information System (INIS)

    Rajesekaran, T.R.; Selvaraj, S.

    2002-01-01

    A systematic study of effects of pairing correlations on nuclear level density parameter 'a' and neutron separation energy S N is presented for 152 Gd using statistical theory of nuclei with deformation, collective and noncollective rotational degrees of freedom, shell effects, and pairing correlations

  2. Pairing correction of particle-hole state densities for two kinds of Fermions

    International Nuclear Information System (INIS)

    Fu, C.Y.

    1985-01-01

    Pairing corrections in particle-hole (exciton) state-density formulas used in precompound nuclear reaction theories are, strictly speaking, dependent on the nuclear excitation energy U and the exciton number n. A general formula for (U,n)-dependent pairing corrections has been derived in an earlier paper for exciton state-density formulas for one kind of Fermion. In the present paper, a similar derivation is made for two kinds of Fermions. It is shown that the constant-pairing-energy correction used in standard level-density formulas, such as U 0 in Gilbert and Cameron, is a limiting case of the present general (U,n)-dependent results

  3. Orbitally limited pair-density-wave phase of multilayer superconductors

    Science.gov (United States)

    Möckli, David; Yanase, Youichi; Sigrist, Manfred

    2018-04-01

    We investigate the magnetic field dependence of an ideal superconducting vortex lattice in the parity-mixed pair-density-wave phase of multilayer superconductors within a circular cell Ginzburg-Landau approach. In multilayer systems, due to local inversion symmetry breaking, a Rashba spin-orbit coupling is induced at the outer layers. This combined with a perpendicular paramagnetic (Pauli) limiting magnetic field stabilizes a staggered layer dependent pair-density-wave phase in the superconducting singlet channel. The high-field pair-density-wave phase is separated from the low-field BCS phase by a first-order phase transition. The motivating guiding question in this paper is: What is the minimal necessary Maki parameter αM for the appearance of the pair-density-wave phase of a superconducting trilayer system? To address this problem we generalize the circular cell method for the regular flux-line lattice of a type-II superconductor to include paramagnetic depairing effects. Then, we apply the model to the trilayer system, where each of the layers are characterized by Ginzburg-Landau parameter κ0 and a Maki parameter αM. We find that when the spin-orbit Rashba interaction compares to the superconducting condensation energy, the orbitally limited pair-density-wave phase stabilizes for Maki parameters αM>10 .

  4. Density functional approach for pairing in finite size systems

    International Nuclear Information System (INIS)

    Hupin, G.

    2011-09-01

    The combination of functional theory where the energy is written as a functional of the density, and the configuration mixing method, provides an efficient description of nuclear ground and excited state properties. The specific pathologies that have been recently observed, show the lack of a clear underlying justification associated to the breaking and the restoration of symmetries within density functional theory. This thesis focuses on alternative treatments of pairing correlations in finite many body systems that consider the breaking and the restoration of the particle number conservation. The energy is written as a functional of a projected quasi-particle vacuum and can be linked to the one obtained within the configuration mixing framework. This approach has been applied to make the projection either before or after the application of the variational principle. It is more flexible than the usual configuration mixing method since it can handle more general effective interactions than the latter. The application to the Krypton isotopes shows the feasibility and the efficiency of the method to describe pairing near closed shell nuclei. Following a parallel path, a theory where the energy is written as a functional of the occupation number and natural orbitals is proposed. The new functional is benchmarked in an exactly solvable model, the pairing Hamiltonian. The efficiency and the applicability of the new theory have been tested for various pairing strengths, single particle energy spectra and numbers of particles. (author)

  5. Nuclear level densities with pairing and self-consistent ground-state shell effects

    CERN Document Server

    Arnould, M

    1981-01-01

    Nuclear level density calculations are performed using a model of fermions interacting via the pairing force, and a realistic single particle potential. The pairing interaction is treated within the BCS approximation with different pairing strength values. The single particle potentials are derived in the framework of an energy-density formalism which describes self-consistently the ground states of spherical nuclei. These calculations are extended to statistically deformed nuclei, whose estimated level densities include rotational band contributions. The theoretical results are compared with various experimental data. In addition, the level densities for several nuclei far from stability are compared with the predictions of a back-shifted Fermi gas model. Such a comparison emphasizes the possible danger of extrapolating to unknown nuclei classical level density formulae whose parameter values are tailored for known nuclei. (41 refs).

  6. Pairing in the BCS and LN approximations using continuum single particle level density

    International Nuclear Information System (INIS)

    Id Betan, R.M.; Repetto, C.E.

    2017-01-01

    Understanding the properties of drip line nuclei requires to take into account the correlations with the continuum spectrum of energy of the system. This paper has the purpose to show that the continuum single particle level density is a convenient way to consider the pairing correlation in the continuum. Isospin mean-field and isospin pairing strength are used to find the Bardeen–Cooper–Schrieffer (BCS) and Lipkin–Nogami (LN) approximate solutions of the pairing Hamiltonian. Several physical properties of the whole chain of the Tin isotope, as gap parameter, Fermi level, binding energy, and one- and two-neutron separation energies, were calculated and compared with other methods and with experimental data when they exist. It is shown that the use of the continuum single particle level density is an economical way to include explicitly the correlations with the continuum spectrum of energy in large scale mass calculation. It is also shown that the computed properties are in good agreement with experimental data and with more sophisticated treatment of the pairing interaction.

  7. Functional approach for pairing in finite systems: How to define restoration of broken symmetries in Energy Density Functional theory?

    International Nuclear Information System (INIS)

    Hupin, G; Lacroix, D; Bender, M

    2011-01-01

    The Multi-Reference Energy Density Functional (MR-EDF) approach (also called configuration mixing or Generator Coordinate Method), that is commonly used to treat pairing in finite nuclei and project onto particle number, is re-analyzed. It is shown that, under certain conditions, the MR-EDF energy can be interpreted as a functional of the one-body density matrix of the projected state with good particle number. Based on this observation, we propose a new approach, called Symmetry-Conserving EDF (SC-EDF), where the breaking and restoration of symmetry are accounted for simultaneously. We show, that such an approach is free from pathologies recently observed in MR-EDF and can be used with a large flexibility on the density dependence of the functional.

  8. Synergy between pair coupled cluster doubles and pair density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Garza, Alejandro J.; Bulik, Ireneusz W. [Department of Chemistry, Rice University, Houston, Texas 77251-1892 (United States); Henderson, Thomas M. [Department of Chemistry and Department of Physics and Astronomy, Rice University, Houston, Texas 77251-1892 (United States); Scuseria, Gustavo E. [Department of Chemistry and Department of Physics and Astronomy, Rice University, Houston, Texas 77251-1892 (United States); Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2015-01-28

    Pair coupled cluster doubles (pCCD) has been recently studied as a method capable of accounting for static correlation with low polynomial cost. We present three combinations of pCCD with Kohn–Sham functionals of the density and on-top pair density (the probability of finding two electrons on top of each other) to add dynamic correlation to pCCD without double counting. With a negligible increase in computational cost, these pCCD+DFT blends greatly improve upon pCCD in the description of typical problems where static and dynamic correlations are both important. We argue that—as a black-box method with low scaling, size-extensivity, size-consistency, and a simple quasidiagonal two-particle density matrix—pCCD is an excellent match for pair density functionals in this type of fusion of multireference wavefunctions with DFT.

  9. Estimating the density-scaling exponent of a monatomic liquid from its pair potential

    DEFF Research Database (Denmark)

    Bøhling, Lasse; Bailey, Nicholas; Schrøder, Thomas

    2014-01-01

    This paper investigates two conjectures for calculating the density dependence of the density-scaling exponent γ of a single-component, pair-potential liquid with strong virial potential-energy correlations. The first conjecture gives an analytical expression for γ directly in terms of the pair...... potential. The second conjecture is a refined version of this involving the most likely nearest-neighbor distance determined from the pair-correlation function. The conjectures are tested by simulations of three systems, one of which is the standard Lennard-Jones liquid. While both expressions give...

  10. Multiconfiguration pair-density functional theory: barrier heights and main group and transition metal energetics.

    Science.gov (United States)

    Carlson, Rebecca K; Li Manni, Giovanni; Sonnenberger, Andrew L; Truhlar, Donald G; Gagliardi, Laura

    2015-01-13

    Kohn-Sham density functional theory, resting on the representation of the electronic density and kinetic energy by a single Slater determinant, has revolutionized chemistry, but for open-shell systems, the Kohn-Sham Slater determinant has the wrong symmetry properties as compared to an accurate wave function. We have recently proposed a theory, called multiconfiguration pair-density functional theory (MC-PDFT), in which the electronic kinetic energy and classical Coulomb energy are calculated from a multiconfiguration wave function with the correct symmetry properties, and the rest of the energy is calculated from a density functional, called the on-top density functional, that depends on the density and the on-top pair density calculated from this wave function. We also proposed a simple way to approximate the on-top density functional by translation of Kohn-Sham exchange-correlation functionals. The method is much less expensive than other post-SCF methods for calculating the dynamical correlation energy starting with a multiconfiguration self-consistent-field wave function as the reference wave function, and initial tests of the theory were quite encouraging. Here, we provide a broader test of the theory by applying it to bond energies of main-group molecules and transition metal complexes, barrier heights and reaction energies for diverse chemical reactions, proton affinities, and the water dimerization energy. Averaged over 56 data points, the mean unsigned error is 3.2 kcal/mol for MC-PDFT, as compared to 6.9 kcal/mol for Kohn-Sham theory with a comparable density functional. MC-PDFT is more accurate on average than complete active space second-order perturbation theory (CASPT2) for main-group small-molecule bond energies, alkyl bond dissociation energies, transition-metal-ligand bond energies, proton affinities, and the water dimerization energy.

  11. Effect of pairing in nuclear level density at low temperatures

    International Nuclear Information System (INIS)

    Rhine Kumar, A.K.; Modi, Swati; Arumugam, P.

    2013-01-01

    The nuclear level density (NLD) has been an interesting topic for researchers, due its importance in many aspects of nuclear physics, nuclear astrophysics, nuclear medicine, and other applied areas. The calculation of NLD helps us to understand the energy distribution of the excited levels of nuclei, entropy, specific heat, reaction cross sections etc. In this work the effect of temperature and pairing on level-density of the nucleus 116 Sn has been studied

  12. Pair breaking and density of states in disordered superconductors

    International Nuclear Information System (INIS)

    Weinkauf, A.; Zittartz, J.

    1975-01-01

    It is shown that pair breaking occurs in a disordered superconductor due to spatial variations of the order parameter, although the system is time reversal invariant. The pair breaking effect is reflected by the occurence of some interesting fine structure in the one particle density of states. Discrete bound states and split-off impurity bands show up in the single impurity case and for very dilute alloys, respectively. For finite alloy concentrations the calculations are done within the CPA. Although principally important, the fine structure is concentrated in an energy range too narrow to be detected experimentally. (orig.) [de

  13. Magnetic Fluctuations in Pair-Density-Wave Superconductors

    Science.gov (United States)

    Christensen, Morten H.; Jacobsen, Henrik; Maier, Thomas A.; Andersen, Brian M.

    2016-04-01

    Pair-density-wave superconductivity constitutes a novel electronic condensate proposed to be realized in certain unconventional superconductors. Establishing its potential existence is important for our fundamental understanding of superconductivity in correlated materials. Here we compute the dynamical magnetic susceptibility in the presence of a pair-density-wave ordered state and study its fingerprints on the spin-wave spectrum including the neutron resonance. In contrast to the standard case of d -wave superconductivity, we show that the pair-density-wave phase exhibits neither a spin gap nor a magnetic resonance peak, in agreement with a recent neutron scattering experiment on underdoped La1.905 Ba0.095 CuO4 [Z. Xu et al., Phys. Rev. Lett. 113, 177002 (2014)].

  14. Metal hydrides based high energy density thermal battery

    International Nuclear Information System (INIS)

    Fang, Zhigang Zak; Zhou, Chengshang; Fan, Peng; Udell, Kent S.; Bowman, Robert C.; Vajo, John J.; Purewal, Justin J.; Kekelia, Bidzina

    2015-01-01

    Highlights: • The principle of the thermal battery using advanced metal hydrides was demonstrated. • The thermal battery used MgH 2 and TiMnV as a working pair. • High energy density can be achieved by the use of MgH 2 to store thermal energy. - Abstract: A concept of thermal battery based on advanced metal hydrides was studied for heating and cooling of cabins in electric vehicles. The system utilized a pair of thermodynamically matched metal hydrides as energy storage media. The pair of hydrides that was identified and developed was: (1) catalyzed MgH 2 as the high temperature hydride material, due to its high energy density and enhanced kinetics; and (2) TiV 0.62 Mn 1.5 alloy as the matching low temperature hydride. Further, a proof-of-concept prototype was built and tested, demonstrating the potential of the system as HVAC for transportation vehicles

  15. Metal hydrides based high energy density thermal battery

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Zhigang Zak, E-mail: zak.fang@utah.edu [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Zhou, Chengshang; Fan, Peng [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Udell, Kent S. [Department of Metallurgical Engineering, The University of Utah, 50 S. Central Campus Dr., Room 2110, Salt Lake City, UT 84112-0114 (United States); Bowman, Robert C. [Department of Metallurgical Engineering, The University of Utah, 135 South 1460 East, Room 412, Salt Lake City, UT 84112-0114 (United States); Vajo, John J.; Purewal, Justin J. [HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA 90265 (United States); Kekelia, Bidzina [Department of Metallurgical Engineering, The University of Utah, 50 S. Central Campus Dr., Room 2110, Salt Lake City, UT 84112-0114 (United States)

    2015-10-05

    Highlights: • The principle of the thermal battery using advanced metal hydrides was demonstrated. • The thermal battery used MgH{sub 2} and TiMnV as a working pair. • High energy density can be achieved by the use of MgH{sub 2} to store thermal energy. - Abstract: A concept of thermal battery based on advanced metal hydrides was studied for heating and cooling of cabins in electric vehicles. The system utilized a pair of thermodynamically matched metal hydrides as energy storage media. The pair of hydrides that was identified and developed was: (1) catalyzed MgH{sub 2} as the high temperature hydride material, due to its high energy density and enhanced kinetics; and (2) TiV{sub 0.62}Mn{sub 1.5} alloy as the matching low temperature hydride. Further, a proof-of-concept prototype was built and tested, demonstrating the potential of the system as HVAC for transportation vehicles.

  16. Gravitational potential energy of a disk-sphere pair of galaxies

    International Nuclear Information System (INIS)

    Ballabh, G.M.

    1975-01-01

    Algebraic expressions are obtained for the interaction potential energy of a pair of galaxies in which one is disk shaped and the other spherical. The density distribution in the disk galaxy is represented by a polynomial in ascending powers of the distance from the centre of the disk while the density distribution in the spherical galaxy is represented by the superposition of spherical polytropes of integral indices. The basic functions required for obtaining the interaction potential energy of a coplanar disk-sphere pair of galaxies are tabulated. The forces of attraction between a coplanar disk-sphere pair of galaxies are shown graphically for two density models of disk and spherical galaxies. An overlapping coplanar disk-sphere pair of galaxies attract just like two mass-points at a certain separation, rsub(c), of their centres. The force of attraction is less than that of two mass-points having masses equal to the masses of the two galaxies, if the separation of the centres is less than rsub(c), and greater if the separation is greater than rsub(c). For a typical coplanar disk-sphere pair of galaxies (the density of the disk is represented by Model II and of the sphere by a polytropic index n=4) of equal radii, the following is noted. At a separation of 0.79 R, R being the common radius of the two galaxies, the force of attraction between the pair is the same as if the entire mass of each galaxy is concentrated at its centre. The mass-point model for the two galaxies will overestimate the force of attraction by more than a factor of 10 if the separation is less than 0.36 R. For separation greater than the radii of the galaxies the mass-point model will underestimate the force but the departure in this case is less than 33%. (Auth.)

  17. Multiconfiguration Pair-Density Functional Theory Is Free From Delocalization Error.

    Science.gov (United States)

    Bao, Junwei Lucas; Wang, Ying; He, Xiao; Gagliardi, Laura; Truhlar, Donald G

    2017-11-16

    Delocalization error has been singled out by Yang and co-workers as the dominant error in Kohn-Sham density functional theory (KS-DFT) with conventional approximate functionals. In this Letter, by computing the vertical first ionization energy for well separated He clusters, we show that multiconfiguration pair-density functional theory (MC-PDFT) is free from delocalization error. To put MC-PDFT in perspective, we also compare it with some Kohn-Sham density functionals, including both traditional and modern functionals. Whereas large delocalization errors are almost universal in KS-DFT (the only exception being the very recent corrected functionals of Yang and co-workers), delocalization error is removed by MC-PDFT, which bodes well for its future as a step forward from KS-DFT.

  18. Exchange-correlation energy from pairing matrix fluctuation and the particle-particle random phase approximation.

    Science.gov (United States)

    van Aggelen, Helen; Yang, Yang; Yang, Weitao

    2014-05-14

    Despite their unmatched success for many applications, commonly used local, semi-local, and hybrid density functionals still face challenges when it comes to describing long-range interactions, static correlation, and electron delocalization. Density functionals of both the occupied and virtual orbitals are able to address these problems. The particle-hole (ph-) Random Phase Approximation (RPA), a functional of occupied and virtual orbitals, has recently known a revival within the density functional theory community. Following up on an idea introduced in our recent communication [H. van Aggelen, Y. Yang, and W. Yang, Phys. Rev. A 88, 030501 (2013)], we formulate more general adiabatic connections for the correlation energy in terms of pairing matrix fluctuations described by the particle-particle (pp-) propagator. With numerical examples of the pp-RPA, the lowest-order approximation to the pp-propagator, we illustrate the potential of density functional approximations based on pairing matrix fluctuations. The pp-RPA is size-extensive, self-interaction free, fully anti-symmetric, describes the strong static correlation limit in H2, and eliminates delocalization errors in H2(+) and other single-bond systems. It gives surprisingly good non-bonded interaction energies--competitive with the ph-RPA--with the correct R(-6) asymptotic decay as a function of the separation R, which we argue is mainly attributable to its correct second-order energy term. While the pp-RPA tends to underestimate absolute correlation energies, it gives good relative energies: much better atomization energies than the ph-RPA, as it has no tendency to underbind, and reaction energies of similar quality. The adiabatic connection in terms of pairing matrix fluctuation paves the way for promising new density functional approximations.

  19. Exchange-correlation energy from pairing matrix fluctuation and the particle-particle random phase approximation

    International Nuclear Information System (INIS)

    Aggelen, Helen van; Yang, Yang; Yang, Weitao

    2014-01-01

    Despite their unmatched success for many applications, commonly used local, semi-local, and hybrid density functionals still face challenges when it comes to describing long-range interactions, static correlation, and electron delocalization. Density functionals of both the occupied and virtual orbitals are able to address these problems. The particle-hole (ph-) Random Phase Approximation (RPA), a functional of occupied and virtual orbitals, has recently known a revival within the density functional theory community. Following up on an idea introduced in our recent communication [H. van Aggelen, Y. Yang, and W. Yang, Phys. Rev. A 88, 030501 (2013)], we formulate more general adiabatic connections for the correlation energy in terms of pairing matrix fluctuations described by the particle-particle (pp-) propagator. With numerical examples of the pp-RPA, the lowest-order approximation to the pp-propagator, we illustrate the potential of density functional approximations based on pairing matrix fluctuations. The pp-RPA is size-extensive, self-interaction free, fully anti-symmetric, describes the strong static correlation limit in H 2 , and eliminates delocalization errors in H 2 + and other single-bond systems. It gives surprisingly good non-bonded interaction energies – competitive with the ph-RPA – with the correct R −6 asymptotic decay as a function of the separation R, which we argue is mainly attributable to its correct second-order energy term. While the pp-RPA tends to underestimate absolute correlation energies, it gives good relative energies: much better atomization energies than the ph-RPA, as it has no tendency to underbind, and reaction energies of similar quality. The adiabatic connection in terms of pairing matrix fluctuation paves the way for promising new density functional approximations

  20. Screening of metal hydride pairs for closed thermal energy storage systems

    International Nuclear Information System (INIS)

    Aswin, N.; Dutta, Pradip; Murthy, S. Srinivasa

    2016-01-01

    Thermal energy storage systems based on metal/hydrides usually are closed systems composed of two beds of metal/alloy – one meant for energy storage and the other for hydrogen storage. It can be shown that a feasible operating cycle for such a system using a pair of metals/alloys operating between specified temperature values can be ensured if the equilibrium hydrogen intake characteristics satisfy certain criteria. In addition, application of first law of thermodynamics to an idealized operating cycle can provide the upper bounds of selected performance indices, namely volumetric energy storage density, energy storage efficiency and peak discharge temperature. This is demonstrated for a representative system composed of LaNi 4.7 Al 0.3 –LaNi 5 operating between 353 K and 303 K which gave values of about 56 kW h m −3 for volumetric storage density, about 85% for energy storage efficiency and 343 K for peak discharge temperature. A system level heat and mass transfer study considering the reaction kinetics, hydrogen flow between the beds and heat exchanger models is presented which gave second level estimates of about 40 kW h m −3 for volumetric energy storage density, 73% for energy storage efficiency and 334 K for peak temperature for the representative system. The results from such studies lead to identifying metal/alloy pairs which can be shortlisted for detailed studies.

  1. A Pair Production Telescope for Medium-Energy Gamma-Ray Polarimetry

    Science.gov (United States)

    Hunter, Stanley D.; Bloser, Peter F.; Depaola, Gerardo; Dion, Michael P.; DeNolfo, Georgia A.; Hanu, Andrei; Iparraguirre, Marcos; Legere, Jason; Longo, Francesco; McConnell, Mark L.; hide

    2014-01-01

    We describe the science motivation and development of a pair production telescope for medium-energy (approximately 5-200 Mega electron Volts) gamma-ray polarimetry. Our instrument concept, the Advanced Energetic Pair Telescope (AdEPT), takes advantage of the Three-Dimensional Track Imager, a low-density gaseous time projection chamber, to achieve angular resolution within a factor of two of the pair production kinematics limit (approximately 0.6 deg at 70 Mega electron Volts), continuum sensitivity comparable with the Fermi-LAT front detector (is less than 3 x 10(exp -6) Mega electron Volts per square centimeter per second at 70 Mega electron Volts), and minimum detectable polarization less than 10% for a 10 milliCrab source in 10(exp 6) s.

  2. Pairing renormalization and regularization within the local density approximation

    International Nuclear Information System (INIS)

    Borycki, P.J.; Dobaczewski, J.; Nazarewicz, W.; Stoitsov, M.V.

    2006-01-01

    We discuss methods used in mean-field theories to treat pairing correlations within the local density approximation. Pairing renormalization and regularization procedures are compared in spherical and deformed nuclei. Both prescriptions give fairly similar results, although the theoretical motivation, simplicity, and stability of the regularization procedure make it a method of choice for future applications

  3. Feasibility Study for a Two-Energy Compact Medical Cyclotron Controlled by Two Pairs of Main Coils

    International Nuclear Information System (INIS)

    Blum, D.; Breckow, J.; Zink, K.

    2013-01-01

    At Paul Scherrer Institute, Villigen, Switzerland, protons are accelerated for the proton therapy by a 250 MeV isochronous cyclotron. As for radiotherapy less energy is required (about 70 MeV) a carbon degrader reduces the extracted beam energy. This involves the increase of emittance, decrease of transmission, more activated components and a higher dose for the staff. By extracting a lower energy beam from the cyclotron, less degrade would be necessary and the above mentioned side-effects could be minimized. A possible solution could be to extract two energies from the cyclotron, 250 MeV for very deep located tumours and 230-235 MeV for others. A technically easy and affordable solution for this problem might be a two-energy cyclotron controlled by just two pairs of main coils. The feasibility of this solution has been analysed in this study. The compounded magnetic flux density B is the sum of the coil's and the iron's flux density. The amount caused by a coil is mainly responsible for the shape of the compounded flux density. Therefore a split of the coil pair was simulated to obtain more possibilities in the adjustment of a lower-energy beam to its ideal isochronous shape. The result is a simulated isochronous 240 MeV beam which was found with an tangential split of the coil pair, their repositioning and the increasing of current in the first coil pair and decreasing in the other one. The tangential split seemed to reduce the problem of the irons linear share of B. This feasibility study is seen as a first step before using 3D-capable software which considers a higher spatial resolution and the influence of temperature.(author)

  4. Spectral density of Cooper pairs in two level quantum dot–superconductors Josephson junction

    Energy Technology Data Exchange (ETDEWEB)

    Dhyani, A., E-mail: archana.d2003@gmail.com [Department of Physics, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India); Rawat, P.S. [Department of Nuclear Science and Technology, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India); Tewari, B.S., E-mail: bstewari@ddn.upes.ac.in [Department of Physics, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India)

    2016-09-15

    Highlights: • The present work deals with the study of the electronic spectral density of electron pairs and its effect in charge transport in superconductor-quantum dot-superconductor junctions. • The charge transfer across such junctions can be controlled by changing the positions of the dot level. • The Josephson supercurrent can also be tuned by controlling the position of quantum dot energy levels. - Abstract: In the present paper, we report the role of quantum dot energy levels on the electronic spectral density for a two level quantum dot coupled to s-wave superconducting leads. The theoretical arguments in this work are based on the Anderson model so that it necessarily includes dot energies, single particle tunneling and superconducting order parameter for BCS superconductors. The expression for single particle spectral function is obtained by using the Green's function equation of motion technique. On the basis of numerical computation of spectral function of superconducting leads, it has been found that the charge transfer across such junctions can be controlled by the positions and availability of the dot levels.

  5. Minimal nuclear energy density functional

    Science.gov (United States)

    Bulgac, Aurel; Forbes, Michael McNeil; Jin, Shi; Perez, Rodrigo Navarro; Schunck, Nicolas

    2018-04-01

    We present a minimal nuclear energy density functional (NEDF) called "SeaLL1" that has the smallest number of possible phenomenological parameters to date. SeaLL1 is defined by seven significant phenomenological parameters, each related to a specific nuclear property. It describes the nuclear masses of even-even nuclei with a mean energy error of 0.97 MeV and a standard deviation of 1.46 MeV , two-neutron and two-proton separation energies with rms errors of 0.69 MeV and 0.59 MeV respectively, and the charge radii of 345 even-even nuclei with a mean error ɛr=0.022 fm and a standard deviation σr=0.025 fm . SeaLL1 incorporates constraints on the equation of state (EoS) of pure neutron matter from quantum Monte Carlo calculations with chiral effective field theory two-body (NN ) interactions at the next-to-next-to-next-to leading order (N3LO) level and three-body (NNN ) interactions at the next-to-next-to leading order (N2LO) level. Two of the seven parameters are related to the saturation density and the energy per particle of the homogeneous symmetric nuclear matter, one is related to the nuclear surface tension, two are related to the symmetry energy and its density dependence, one is related to the strength of the spin-orbit interaction, and one is the coupling constant of the pairing interaction. We identify additional phenomenological parameters that have little effect on ground-state properties but can be used to fine-tune features such as the Thomas-Reiche-Kuhn sum rule, the excitation energy of the giant dipole and Gamow-Teller resonances, the static dipole electric polarizability, and the neutron skin thickness.

  6. Simultaneous evaluation of the shell and pairing corrections to the nuclear deformation energy: the case of odd-systems

    International Nuclear Information System (INIS)

    Benhamouda, N.; Oudih, M.R.

    2002-01-01

    A method of simultaneous evaluation of the shell and pairing corrections to the nuclear deformation energy, recently proposed for the even-even nuclei, is generalized to the case of odd systems. * By means of the blocked-level technique, a level density with explicit dependence on pairing correlations is defined. The microscopic corrections to the deformation energy are then determined by a procedure which is analogous to that of Strutinsky. The method is applied to the ground state of Europium isotopes using the single-particle energies of a deformed Woods-Saxon mean-field. The obtained results are in good agreement with the experimental values

  7. Multiconfiguration Pair-Density Functional Theory Outperforms Kohn-Sham Density Functional Theory and Multireference Perturbation Theory for Ground-State and Excited-State Charge Transfer.

    Science.gov (United States)

    Ghosh, Soumen; Sonnenberger, Andrew L; Hoyer, Chad E; Truhlar, Donald G; Gagliardi, Laura

    2015-08-11

    The correct description of charge transfer in ground and excited states is very important for molecular interactions, photochemistry, electrochemistry, and charge transport, but it is very challenging for Kohn-Sham (KS) density functional theory (DFT). KS-DFT exchange-correlation functionals without nonlocal exchange fail to describe both ground- and excited-state charge transfer properly. We have recently proposed a theory called multiconfiguration pair-density functional theory (MC-PDFT), which is based on a combination of multiconfiguration wave function theory with a new type of density functional called an on-top density functional. Here we have used MC-PDFT to study challenging ground- and excited-state charge-transfer processes by using on-top density functionals obtained by translating KS exchange-correlation functionals. For ground-state charge transfer, MC-PDFT performs better than either the PBE exchange-correlation functional or CASPT2 wave function theory. For excited-state charge transfer, MC-PDFT (unlike KS-DFT) shows qualitatively correct behavior at long-range with great improvement in predicted excitation energies.

  8. Approach to equilibrium in a pure superconductor. The relaxation of the Cooper pair density

    Energy Technology Data Exchange (ETDEWEB)

    Schid, A

    1968-01-01

    Electron-phonon and electron-electron collisions are the processes which determine the relaxation time r/sub R/ of the Cooper pair density. The case is considered for which the deviation of the pair density from equilibrium is small and where the equilibrium state is homogeneous. Starting from the Eliashberg equation one is able to reduce the problem to a quadrature once the equilibrium Green functions are known.

  9. Pairing gaps from nuclear mean-field models

    International Nuclear Information System (INIS)

    Bender, M.; Rutz, K.; Maruhn, J.A.

    2000-01-01

    We discuss the pairing gap, a measure for nuclear pairing correlations, in chains of spherical, semi-magic nuclei in the framework of self-consistent nuclear mean-field models. The equations for the conventional BCS model and the approximate projection-before-variation Lipkin-Nogami method are formulated in terms of local density functionals for the effective interaction. We calculate the Lipkin-Nogami corrections of both the mean-field energy and the pairing energy. Various definitions of the pairing gap are discussed as three-point, four-point and five-point mass-difference formulae, averaged matrix elements of the pairing potential, and single-quasiparticle energies. Experimental values for the pairing gap are compared with calculations employing both a delta pairing force and a density-dependent delta interaction in the BCS and Lipkin-Nogami model. Odd-mass nuclei are calculated in the spherical blocking approximation which neglects part of the the core polarization in the odd nucleus. We find that the five-point mass difference formula gives a very robust description of the odd-even staggering, other approximations for the gap may differ from that up to 30% for certain nuclei. (orig.)

  10. Simultaneous evaluation of the shell and pairing corrections to the nuclear deformation energy: the case of odd-systems

    Energy Technology Data Exchange (ETDEWEB)

    Benhamouda, N [Laboratoire de Physique Theoique, Faculte des Sciences, USTHB BP 32 El-Alia, 16111 Bab-Ezzouar, Algers (Algeria); Oudih, M R [CRNA, 2. Bd Frantz Fanon, BP 399 Alger-Gare, Algers (Algeria)

    2002-09-15

    A method of simultaneous evaluation of the shell and pairing corrections to the nuclear deformation energy, recently proposed for the even-even nuclei, is generalized to the case of odd systems. {sup *} By means of the blocked-level technique, a level density with explicit dependence on pairing correlations is defined. The microscopic corrections to the deformation energy are then determined by a procedure which is analogous to that of Strutinsky. The method is applied to the ground state of Europium isotopes using the single-particle energies of a deformed Woods-Saxon mean-field. The obtained results are in good agreement with the experimental values.

  11. Mesoscopic pairing without superconductivity

    Science.gov (United States)

    Hofmann, Johannes

    2017-12-01

    We discuss pairing signatures in mesoscopic nanowires with a variable attractive pairing interaction. Depending on the wire length, density, and interaction strength, these systems realize a simultaneous bulk-to-mesoscopic and BCS-BEC crossover, which we describe in terms of the parity parameter that quantifies the odd-even energy difference and generalizes the bulk Cooper pair binding energy to mesoscopic systems. We show that the parity parameter can be extracted from recent measurements of conductance oscillations in SrTiO3 nanowires by Cheng et al. [Nature (London) 521, 196 (2015), 10.1038/nature14398], where it marks the critical magnetic field that separates pair and single-particle currents. Our results place the experiment in the fluctuation-dominated mesoscopic regime on the BCS side of the crossover.

  12. A method for conversion of Hounsfield number to electron density and prediction of macroscopic pair production cross-sections

    International Nuclear Information System (INIS)

    Knoeoes, T.; Nilsson, M.; Ahlgren, L.

    1986-01-01

    A method for the determination of electron density using a narrow beam attenuation geometry is described. The method does not require that the elemental composition of the phantom materials is known. The Hounsfield numbers for the phantom materials used were determined using five different CT scanners. A relationship between Hounsfield number and electron density can thus be established, which is of considerable value in radiation therapy treatment planning procedures. Measurements of the ratio coherent/incoherent scattering of low energy photons in a certain geometry has proven valuable for determination of atomic number, which in its turn can be used for estimation of macroscopic pair production coefficients for high energy photons. The combination of knowledge of electron density with methods for determination of processes, dependent on atomic number, can form a base for adequate composition of phantom materials for purposes of testing dose calculation algorithms for photons and electrons. (orig.)

  13. Properties of short-range and long-range correlation energy density functionals from electron-electron coalescence

    International Nuclear Information System (INIS)

    Gori-Giorgi, Paola; Savin, Andreas

    2006-01-01

    The combination of density-functional theory with other approaches to the many-electron problem through the separation of the electron-electron interaction into a short-range and a long-range contribution is a promising method, which is raising more and more interest in recent years. In this work some properties of the corresponding correlation energy functionals are derived by studying the electron-electron coalescence condition for a modified (long-range-only) interaction. A general relation for the on-top (zero electron-electron distance) pair density is derived, and its usefulness is discussed with some examples. For the special case of the uniform electron gas, a simple parametrization of the on-top pair density for a long-range only interaction is presented and supported by calculations within the ''extended Overhauser model.'' The results of this work can be used to build self-interaction corrected short-range correlation energy functionals

  14. Local free energies for the coarse-graining of adsorption phenomena: The interacting pair approximation

    Science.gov (United States)

    Pazzona, Federico G.; Pireddu, Giovanni; Gabrieli, Andrea; Pintus, Alberto M.; Demontis, Pierfranco

    2018-05-01

    We investigate the coarse-graining of host-guest systems under the perspective of the local distribution of pore occupancies, along with the physical meaning and actual computability of the coarse-interaction terms. We show that the widely accepted approach, in which the contributions to the free energy given by the molecules located in two neighboring pores are estimated through Monte Carlo simulations where the two pores are kept separated from the rest of the system, leads to inaccurate results at high sorbate densities. In the coarse-graining strategy that we propose, which is based on the Bethe-Peierls approximation, density-independent interaction terms are instead computed according to local effective potentials that take into account the correlations between the pore pair and its surroundings by means of mean-field correction terms without the need for simulating the pore pair separately. Use of the interaction parameters obtained this way allows the coarse-grained system to reproduce more closely the equilibrium properties of the original one. Results are shown for lattice-gases where the local free energy can be computed exactly and for a system of Lennard-Jones particles under the effect of a static confining field.

  15. Performance of various density functionals for the hydrogen bonds in DNA base pairs

    NARCIS (Netherlands)

    van der Wijst, T.; Fonseca Guerra, C.; Swart, M.; Bickelhaupt, F.M.

    2006-01-01

    We have investigated the performance of seven popular density functionals (B3LYP, BLYP, BP86, mPW, OPBE, PBE, PW91) for describing the geometry and stability of the hydrogen bonds in DNA base pairs. For the gas-phase situation, the hydrogen-bond lengths and strengths in the DNA pairs have been

  16. Cooper-pair size and binding energy for unconventional superconducting systems

    Science.gov (United States)

    Dinóla Neto, F.; Neto, Minos A.; Salmon, Octavio D. Rodriguez

    2018-06-01

    The main proposal of this paper is to analyze the size of the Cooper pairs composed by unbalanced mass fermions from different electronic bands along the BCS-BEC crossover and study the binding energy of the pairs. We are considering an interaction between fermions with different masses leading to an inter-band pairing. In addiction to the attractive interaction we have an hybridization term to couple both bands, which in general acts unfavorable for the pairing between the electrons. We get first order phase transitions as the hybridization breaks the Cooper pairs for the s-wave symmetry of the gap amplitude. The results show the dependence of the Cooper-pair size as a function of the hybridization for T = 0 . We also propose the structure of the binding energy of the inter-band system as a function of the two-bands quasi-particle energies.

  17. Triton-3He relative and differential flows as probes of the nuclear symmetry energy at supra-saturation densities

    International Nuclear Information System (INIS)

    Yong Gaochan; Li Baoan; Chen Liewen; Zhang Xunchao

    2009-01-01

    Using a transport model coupled with a phase-space coalescence afterburner, we study the triton- 3 He (t- 3 He) ratio with both relative and differential transverse flows in semicentral 132 Sn+ 124 Sn reactions at a beam energy of 400 MeV/nucleon. The neutron-proton ratios with relative and differential flows are also discussed as a reference. We find that similar to the neutron-proton pairs, the t- 3 He pairs also carry interesting information regarding the density dependence of the nuclear symmetry energy. Moreover, the nuclear symmetry energy affects more strongly the t- 3 He relative and differential flows than the π - /π + ratio in the same reaction. The t- 3 He relative flow can be used as a particularly powerful probe of the high-density behavior of the nuclear symmetry energy.

  18. Pair Formation of Hard Core Bosons in Flat Band Systems

    Science.gov (United States)

    Mielke, Andreas

    2018-05-01

    Hard core bosons in a large class of one or two dimensional flat band systems have an upper critical density, below which the ground states can be described completely. At the critical density, the ground states are Wigner crystals. If one adds a particle to the system at the critical density, the ground state and the low lying multi particle states of the system can be described as a Wigner crystal with an additional pair of particles. The energy band for the pair is separated from the rest of the multi-particle spectrum. The proofs use a Gerschgorin type of argument for block diagonally dominant matrices. In certain one-dimensional or tree-like structures one can show that the pair is localised, for example in the chequerboard chain. For this one-dimensional system with periodic boundary condition the energy band for the pair is flat, the pair is localised.

  19. Magnetic energy density and plasma energy density in the Venus wake

    Science.gov (United States)

    Perez De Tejada, H. A.; Durand-Manterola, H. J.; Lundin, R.; Barabash, S.; Zhang, T.; Reyes-Ruiz, M.; Sauvaud, J.

    2013-05-01

    Magnetic energy density and plasma energy density in the Venus wake H. Pérez-de-Tejada1, H. Durand-Manterola1, R. Lundin2, S. Barabash2, T. L. Zhang3, A. Sauvaud4, M. Reyes-Ruiz5. 1 - Institute of Geophysics, UNAM, México, D. F. 2 - Swedish Institute of Space Physics, Umea, Sweden 3 - Space Research Institute, Graz, Austria 4 - CESR, Toulouse, France 5 - Institute of Astronomy, UNAM, Ensenada, México Measurements conducted in the Venus wake with the magnetometer and the Aspera-4 plasma instrument of the Venus Express spacecraft show that average values of the kinetic energy density of the plasma in that region are comparable to average local values of the magnetic energy density. Observations were carried out in several orbits of the Venus Express near the midnight plane and suggest that the total energy content in the Venus wake is distributed with nearly comparable values between the plasma and the magnetic field. Processes associated with the solar wind erosion of planetary ions from the polar magnetic regions of the ionosphere are involved in the comparable distribution of both energy components.

  20. Modeling nuclear weak-interaction processes with relativistic energy density functionals

    International Nuclear Information System (INIS)

    Paar, N.; Marketin, T.; Vale, D.; Vretenar, D.

    2015-01-01

    Relativistic energy density functionals have become a standard framework for nuclear structure studies of ground state properties and collective excitations over the entire nuclide chart. In this paper, we review recent developments in modeling nuclear weak-interaction processes: Charge-exchange excitations and the role of isoscalar proton–neutron pairing, charged-current neutrino–nucleus reactions relevant for supernova evolution and neutrino detectors and calculation of β-decay rates for r-process nucleosynthesis. (author)

  1. Theoretical Probing of Weak Anion-Cation Interactions in Certain Pyridinium-Based Ionic Liquid Ion Pairs and the Application of Molecular Electrostatic Potential in Their Ionic Crystal Density Determination: A Comparative Study Using Density Functional Approach.

    Science.gov (United States)

    Joseph, Aswathy; Thomas, Vibin Ipe; Żyła, Gaweł; Padmanabhan, A S; Mathew, Suresh

    2018-01-11

    A comprehensive study on the structure, nature of interaction, and properties of six ionic pairs of 1-butylpyridinium and 1-butyl-4-methylpyridinium cations in combination with tetrafluoroborate (BF 4 - ), chloride (Cl - ), and bromide (Br - ) anions have been carried out using density functional theory (DFT). The anion-cation interaction energy (ΔE int ), thermochemistry values, theoretical band gap, molecular orbital energy order, DFT-based chemical activity descriptors [chemical potential (μ), chemical hardness (η), and electrophilicity index (ω)], and distribution of density of states (DOS) of these ion pairs were investigated. The ascendancy of the -CH 3 substituent at the fourth position of the 1-butylpyridinium cation ring on the values of ΔE int , theoretical band gap and chemical activity descriptors was evaluated. The ΔE int values were negative for all six ion pairs and were highest for Cl - containing ion pairs. The theoretical band gap value after -CH 3 substitution increased from 3.78 to 3.96 eV (for Cl - ) and from 2.74 to 2.88 eV (for Br - ) and decreased from 4.9 to 4.89 eV (for BF 4 - ). Ion pairs of BF 4 - were more susceptible to charge transfer processes as inferred from their significantly high η values and comparatively small difference in ω value after -CH 3 substitution. The change in η and μ values due to the -CH 3 substituent is negligibly small in all cases except for the ion pairs of Cl - . Critical-point (CP) analyses were carried out to investigate the AIM topological parameters at the interionic bond critical points (BCPs). The RDG isosurface analysis indicated that the anion-cation interaction was dominated by strong H cat ···X ani and C cat ···X ani interactions in ion pairs of Cl - and Br - whereas a weak van der Waal's effect dominated in ion pairs of BF 4 - . The molecular electrostatic potential (MESP)-based parameter ΔΔV min measuring the anion-cation interaction strength showed a good linear correlation with

  2. Dual origin of pairing in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Idini, A. [University of Jyvaskyla, Department of Physics (Finland); Potel, G. [Michigan State University, National Superconducting Cyclotron Laboratory (United States); Barranco, F. [Escuela Superior de Ingenieros, Universidad de Sevilla, Departamento de Fìsica Aplicada III (Spain); Vigezzi, E., E-mail: enrico.vigezzi@mi.infn.it [INFN Sezione di Milano (Italy); Broglia, R. A. [Università di Milano, Dipartimento di Fisica (Italy)

    2016-11-15

    The pairing correlations of the nucleus {sup 120}Sn are calculated by solving the Nambu–Gor’kov equations, including medium polarization effects resulting from the interweaving of quasiparticles, spin and density vibrations, taking into account, within the framework of nuclear field theory (NFT), processes leading to self-energy and vertex corrections and to the induced pairing interaction. From these results one can not only demonstrate the inevitability of the dual origin of pairing in nuclei, but also extract information which can be used at profit to quantitatively disentangle the contributions to the pairing gap Δ arising from the bare and from the induced pairing interaction. The first is the strong {sup 1}S{sub 0} short-range NN potential resulting from meson exchange between nucleons moving in time reversal states within an energy range of hundreds of MeV from the Fermi energy. The second results from the exchange of vibrational modes between nucleons moving within few MeV from the Fermi energy. Short- (v{sub p}{sup bare}) and long-range (v{sub p}{sup ind}) pairing interactions contribute essentially equally to nuclear Cooper pair stability. That is to the breaking of gauge invariance in open-shell superfluid nuclei and thus to the order parameter, namely to the ground state expectation value of the pair creation operator. In other words, to the emergent property of generalized rigidity in gauge space, and associated rotational bands and Cooper pair tunneling between members of these bands.

  3. Dual origin of pairing in nuclei

    Science.gov (United States)

    Idini, A.; Potel, G.; Barranco, F.; Vigezzi, E.; Broglia, R. A.

    2016-11-01

    The pairing correlations of the nucleus 120Sn are calculated by solving the Nambu-Gor'kov equations, including medium polarization effects resulting from the interweaving of quasiparticles, spin and density vibrations, taking into account, within the framework of nuclear field theory (NFT), processes leading to self-energy and vertex corrections and to the induced pairing interaction. From these results one can not only demonstrate the inevitability of the dual origin of pairing in nuclei, but also extract information which can be used at profit to quantitatively disentangle the contributions to the pairing gap Δ arising from the bare and from the induced pairing interaction. The first is the strong 1 S 0 short-range NN potential resulting from meson exchange between nucleons moving in time reversal states within an energy range of hundreds of MeV from the Fermi energy. The second results from the exchange of vibrational modes between nucleons moving within few MeV from the Fermi energy. Short- ( v p bare) and long-range ( v p ind) pairing interactions contribute essentially equally to nuclear Cooper pair stability. That is to the breaking of gauge invariance in open-shell superfluid nuclei and thus to the order parameter, namely to the ground state expectation value of the pair creation operator. In other words, to the emergent property of generalized rigidity in gauge space, and associated rotational bands and Cooper pair tunneling between members of these bands.

  4. Quasiparticle density of states in a half metal in the presence of odd-frequency Cooper pairs

    NARCIS (Netherlands)

    Asano, Yasuhiro; Yokoyama, Takehito; Tanaka, Yukio; Golubov, Alexandre Avraamovitch

    2008-01-01

    We study the local density of states in a half metal sandwiched by the two superconductors. The spin-flip scattering at the junction interface opens the Josephson channels of the odd-frequency spin-triplet s-wave Cooper pairs. The penetration of the odd-frequency pairs enhances the quasiparticle

  5. Numerical analysis of energy density and particle density in high energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Fu Yuanyong; Lu Zhongdao

    2004-01-01

    Energy density and particle density in high energy heavy-ion collisions are calculated with infinite series expansion method and Gauss-Laguerre formulas in numerical integration separately, and the results of these two methods are compared, the higher terms and linear terms in series expansion are also compared. The results show that Gauss-Laguerre formulas is a good method in calculations of high energy heavy-ion collisions. (author)

  6. Energy vs. density on paths toward more exact density functionals.

    Science.gov (United States)

    Kepp, Kasper P

    2018-03-14

    Recently, the progression toward more exact density functional theory has been questioned, implying a need for more formal ways to systematically measure progress, i.e. a "path". Here I use the Hohenberg-Kohn theorems and the definition of normality by Burke et al. to define a path toward exactness and "straying" from the "path" by separating errors in ρ and E[ρ]. A consistent path toward exactness involves minimizing both errors. Second, a suitably diverse test set of trial densities ρ' can be used to estimate the significance of errors in ρ without knowing the exact densities which are often inaccessible. To illustrate this, the systems previously studied by Medvedev et al., the first ionization energies of atoms with Z = 1 to 10, the ionization energy of water, and the bond dissociation energies of five diatomic molecules were investigated using CCSD(T)/aug-cc-pV5Z as benchmark at chemical accuracy. Four functionals of distinct designs was used: B3LYP, PBE, M06, and S-VWN. For atomic cations regardless of charge and compactness up to Z = 10, the energy effects of the different ρ are energy-wise insignificant. An interesting oscillating behavior in the density sensitivity is observed vs. Z, explained by orbital occupation effects. Finally, it is shown that even large "normal" problems such as the Co-C bond energy of cobalamins can use simpler (e.g. PBE) trial densities to drastically speed up computation by loss of a few kJ mol -1 in accuracy. The proposed method of using a test set of trial densities to estimate the sensitivity and significance of density errors of functionals may be useful for testing and designing new balanced functionals with more systematic improvement of densities and energies.

  7. Approximations for W-Pair Production at Linear-Collider Energies

    CERN Document Server

    Denner, A

    1997-01-01

    We determine the accuracy of various approximations to the O(alpha) corrections for on-shell W-pair production. While an approximation based on the universal corrections arising from initial-state radiation, from the running of alpha, and from corrections proportional to m_t^2 fails in the Linear-Collider energy range, a high-energy approximation improved by the exact universal corrections is sufficiently good above about 500GeV. These results indicate that in Monte Carlo event generators for off-shell W-pair production the incorporation of the universal corrections is not sufficient and more corrections should be included.

  8. Kepler-36: a pair of planets with neighboring orbits and dissimilar densities.

    Science.gov (United States)

    Carter, Joshua A; Agol, Eric; Chaplin, William J; Basu, Sarbani; Bedding, Timothy R; Buchhave, Lars A; Christensen-Dalsgaard, Jørgen; Deck, Katherine M; Elsworth, Yvonne; Fabrycky, Daniel C; Ford, Eric B; Fortney, Jonathan J; Hale, Steven J; Handberg, Rasmus; Hekker, Saskia; Holman, Matthew J; Huber, Daniel; Karoff, Christopher; Kawaler, Steven D; Kjeldsen, Hans; Lissauer, Jack J; Lopez, Eric D; Lund, Mikkel N; Lundkvist, Mia; Metcalfe, Travis S; Miglio, Andrea; Rogers, Leslie A; Stello, Dennis; Borucki, William J; Bryson, Steve; Christiansen, Jessie L; Cochran, William D; Geary, John C; Gilliland, Ronald L; Haas, Michael R; Hall, Jennifer; Howard, Andrew W; Jenkins, Jon M; Klaus, Todd; Koch, David G; Latham, David W; MacQueen, Phillip J; Sasselov, Dimitar; Steffen, Jason H; Twicken, Joseph D; Winn, Joshua N

    2012-08-03

    In the solar system, the planets' compositions vary with orbital distance, with rocky planets in close orbits and lower-density gas giants in wider orbits. The detection of close-in giant planets around other stars was the first clue that this pattern is not universal and that planets' orbits can change substantially after their formation. Here, we report another violation of the orbit-composition pattern: two planets orbiting the same star with orbital distances differing by only 10% and densities differing by a factor of 8. One planet is likely a rocky "super-Earth," whereas the other is more akin to Neptune. These planets are 20 times more closely spaced and have a larger density contrast than any adjacent pair of planets in the solar system.

  9. A finite range pairing force for density functional theory in superfluid nuclei

    International Nuclear Information System (INIS)

    Tian, Y.; Ma, Z.Y.; Ring, P.

    2009-01-01

    The problem of pairing in the 1 S 0 channel of finite nuclei is revisited. In nuclear matter forces of separable form can be adjusted to the bare nuclear force, to any phenomenological pairing interaction such as the Gogny force or to exact solutions of the gap equation. In finite nuclei, because of translational invariance, such forces are no longer separable. Using well-known techniques of Talmi and Moshinsky we expand the matrix elements in a series of separable terms, which converges quickly preserving translational invariance and finite range. In this way the complicated problem of a cut-off at large momenta or energies inherent in other separable or zero range pairing forces is avoided. Applications in the framework of the relativistic Hartree-Bogoliubov approach show that the pairing properties are depicted on almost the same footing as by the original pairing interaction not only in nuclear matter, but also in finite nuclei. This simple separable force can be easily applied for the investigation of pairing properties in nuclei far from stability as well as for further investigations going beyond mean field theory.

  10. Lepton pair production at ISR energies and QCD

    International Nuclear Information System (INIS)

    Altarelli, G.; Martinelli, G.

    1985-01-01

    Motivated by some recent results from the ISR we have considered all available data on the production of Drell-Yan pairs by high energy proton beams. We show that the lepton pair cross sections and qsub(T) distributions are correctly described by QCD using the known distributions of partons in the proton and acceptable values of the QCD scale Λ. No other free parameter is required. Within the accuracy of the data no appreciable intrinsic transverse momentum is needed. (orig.)

  11. Possibility of ΛΛ pairing and its dependence on background density in a relativistic Hartree-Bogoliubov model

    International Nuclear Information System (INIS)

    Tanigawa, Tomonori; Matsuzaki, Masayuki; Chiba, Satoshi

    2003-01-01

    We calculate a ΛΛ pairing gap in binary mixed matter of nucleons and Λ hyperons within the relativistic Hartree-Bogoliubov model. Λ hyperons to be paired up are immersed in background nucleons in a normal state. The gap is calculated with a one-boson-exchange interaction obtained from a relativistic Lagrangian. It is found that at background density ρ N =2.5ρ 0 the ΛΛ pairing gap is very small, and that a denser background makes it rapidly suppressed. This result suggests a mechanism, specific to mixed matter dealt with relativistic models, of its dependence on the nucleon density. An effect of weaker ΛΛ attraction on the gap is also examined in connection with the revised information of the ΛΛ interaction

  12. The effect of sensory-nutrient congruency on food intake after repeated exposure: do texture and/or energy density matter?

    Science.gov (United States)

    Hogenkamp, P S

    2014-09-01

    Sensory properties guide the amount that people eat. In particular, food texture plays an important role in a food's 'expected satiation', which in turn affects the food-related decision making process. One hypothesis is that incongruent pairing of a textural cue with a post-ingestive outcome compromises this process, leading to poor energy compensation. Several studies examined the effect of both energy density and sensory characteristics (i.e. increased creaminess and thickness) on expectations, subjective appetite and food intake. To add to this literature, a re-analysis of data assessed whether the effect of sensory-nutrient pairings on energy intake compensation persisted after repeated exposure to a food. In this cross-over design, 27 participants consumed two preloads with 'congruent' (low-energy/liquid; high-energy/semi-solid) and two preloads with 'incongruent' (low-energy/semi-solid; high-energy/liquid) texture-nutrient combinations for nine subsequent meals, during which ad libitum intake was measured. Intake at first exposure did not differ between the low-energy (280±150kcal) and high-energy preloads (292±183kcal) in the incongruent conditions. By contrast, it was greater after the low-energy (332±203kcal) than after the high-energy (236±132kcal) preload in the congruent conditions (energy∗incongruent/congruent, p=0.04). Post-exposure, this pattern changed: intake depended on the energy density of the preloads in all conditions, and was greater after low-energy preloads (day∗energy∗incongruent/congruent-interaction for breakfast: p=0.02). Thus, manipulating the sensory properties of a food influenced energy compensation and meal size, but only at initial exposure. Repeated exposure 'corrected' the initial lack of compensation observed in conditions with incongruent sensory-nutrient pairings. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Kepler-36: A Pair of Planets with Neighboring Orbits and Dissimilar Densities

    Energy Technology Data Exchange (ETDEWEB)

    Carter, J. A.; Agol, E.; Chaplin, W. J.; Basu, S.; Bedding, T. R.; Buchhave, L. A.; Christensen-Dalsgaard, J.; Deck, K. M.; Elsworth, Y.; Fabrycky, D. C.; Ford, E. B.; Fortney, J. J.; Hale, S. J.; Handberg, R.; Hekker, S.; Holman, M. J.; Huber, D.; Karoff, C.; Kawaler, S. D.; Kjeldsen, H.; Lissauer, J. J.; Lopez, E. D.; Lund, M. N.; Lundkvist, M.; Metcalfe, T. S.; Miglio, A.; Rogers, L. A.; Stello, D.; Borucki, W. J.; Bryson, S.; Christiansen, J. L.; Cochran, W. D.; Geary, J. C.; Gilliland, R. L.; Haas, M. R.; Hall, J.; Howard, A. W.; Jenkins, J. M.; Klaus, T.; Koch, D. G.; Latham, D. W.; MacQueen, P. J.; Sasselov, D.; Steffen, J. H.; Twicken, J. D.; Winn, J. N.

    2012-06-21

    In the Solar system the planets' compositions vary with orbital distance, with rocky planets in close orbits and lower-density gas giants in wider orbits. The detection of close-in giant planets around other stars was the first clue that this pattern is not universal, and that planets' orbits can change substantially after their formation. Here we report another violation of the orbit-composition pattern: two planets orbiting the same star with orbital distances differing by only 10%, and densities differing by a factor of 8. One planet is likely a rocky `super-Earth', whereas the other is more akin to Neptune. These planets are thirty times more closely spaced--and have a larger density contrast--than any adjacent pair of planets in the Solar system.

  14. Influence of Hydration on Proton Transfer in the Guanine-Cytosine Radical Cation (G•+-C) Base Pair: A Density Functional Theory Study

    Science.gov (United States)

    Kumar, Anil; Sevilla, Michael D.

    2009-01-01

    On one-electron oxidation all molecules including DNA bases become more acidic in nature. For the GC base pair experiments suggest that a facile proton transfer takes place in the G•+-C base pair from N1 of G•+ to N3 of cytosine. This intra-base pair proton transfer reaction has been extensively considered using theoretical methods for the gas phase and it is predicted that the proton transfer is slightly unfavorable in disagreement with experiment. In the present study, we consider the effect of the first hydration layer on the proton transfer reaction in G•+-C by the use of density functional theory (DFT), B3LYP/6-31+G** calculations of the G•+-C base pair in the presence of 6 and 11 water molecules. Under the influence of hydration of 11 waters, a facile proton transfer from N1 of G•+ to N3 of C is predicted. The zero point energy (ZPE) corrected forward and backward energy barriers, for the proton transfer from N1 of G•+ to N3 of C, was found to be 1.4 and 2.6 kcal/mol, respectively. The proton transferred G•-(H+)C + 11H2O was found to be 1.2 kcal/mol more stable than G•+-C + 11H2O in agreement with experiment. The present calculation demonstrates that the inclusion of the first hydration shell around G•+-C base pair has an important effect on the internal proton transfer energetics. PMID:19485319

  15. Fission level densities

    International Nuclear Information System (INIS)

    Maslov, V.M.

    1998-01-01

    Fission level densities (or fissioning nucleus level densities at fission saddle deformations) are required for statistical model calculations of actinide fission cross sections. Back-shifted Fermi-Gas Model, Constant Temperature Model and Generalized Superfluid Model (GSM) are widely used for the description of level densities at stable deformations. These models provide approximately identical level density description at excitations close to the neutron binding energy. It is at low excitation energies that they are discrepant, while this energy region is crucial for fission cross section calculations. A drawback of back-shifted Fermi gas model and traditional constant temperature model approaches is that it is difficult to include in a consistent way pair correlations, collective effects and shell effects. Pair, shell and collective properties of nucleus do not reduce just to the renormalization of level density parameter a, but influence the energy dependence of level densities. These effects turn out to be important because they seem to depend upon deformation of either equilibrium or saddle-point. These effects are easily introduced within GSM approach. Fission barriers are another key ingredients involved in the fission cross section calculations. Fission level density and barrier parameters are strongly interdependent. This is the reason for including fission barrier parameters along with the fission level densities in the Starter File. The recommended file is maslov.dat - fission barrier parameters. Recent version of actinide fission barrier data obtained in Obninsk (obninsk.dat) should only be considered as a guide for selection of initial parameters. These data are included in the Starter File, together with the fission barrier parameters recommended by CNDC (beijing.dat), for completeness. (author)

  16. Measuring top-quark polarization in top-pair + missing-energy events.

    Science.gov (United States)

    Berger, Edmond L; Cao, Qing-Hong; Yu, Jiang-Hao; Zhang, Hao

    2012-10-12

    The polarization of a top quark can be sensitive to new physics beyond the standard model. Since the charged lepton from top-quark decay is maximally correlated with the top-quark spin, it is common to measure the polarization from the distribution in the angle between the charged lepton and the top-quark directions. We propose a novel method based on the charged lepton energy fraction and illustrate the method with a detailed simulation of top-quark pairs produced in supersymmetric top squark pair production. We show that the lepton energy ratio distribution that we define is very sensitive to the top-quark polarization but insensitive to the precise measurement of the top-quark energy.

  17. Colloids exposed to random potential energy landscapes: From particle number density to particle-potential and particle-particle interactions

    International Nuclear Information System (INIS)

    Bewerunge, Jörg; Capellmann, Ronja F.; Platten, Florian; Egelhaaf, Stefan U.; Sengupta, Ankush; Sengupta, Surajit

    2016-01-01

    Colloidal particles were exposed to a random potential energy landscape that has been created optically via a speckle pattern. The mean particle density as well as the potential roughness, i.e., the disorder strength, were varied. The local probability density of the particles as well as its main characteristics were determined. For the first time, the disorder-averaged pair density correlation function g (1) (r) and an analogue of the Edwards-Anderson order parameter g (2) (r), which quantifies the correlation of the mean local density among disorder realisations, were measured experimentally and shown to be consistent with replica liquid state theory results.

  18. Single-particle energies and density of states in density functional theory

    Science.gov (United States)

    van Aggelen, H.; Chan, G. K.-L.

    2015-07-01

    Time-dependent density functional theory (TD-DFT) is commonly used as the foundation to obtain neutral excited states and transition weights in DFT, but does not allow direct access to density of states and single-particle energies, i.e. ionisation energies and electron affinities. Here we show that by extending TD-DFT to a superfluid formulation, which involves operators that break particle-number symmetry, we can obtain the density of states and single-particle energies from the poles of an appropriate superfluid response function. The standard Kohn- Sham eigenvalues emerge as the adiabatic limit of the superfluid response under the assumption that the exchange- correlation functional has no dependence on the superfluid density. The Kohn- Sham eigenvalues can thus be interpreted as approximations to the ionisation energies and electron affinities. Beyond this approximation, the formalism provides an incentive for creating a new class of density functionals specifically targeted at accurate single-particle eigenvalues and bandgaps.

  19. Pair-density waves, charge-density waves, and vortices in high-Tc cuprates

    Science.gov (United States)

    Dai, Zhehao; Zhang, Ya-Hui; Senthil, T.; Lee, Patrick A.

    2018-05-01

    A recent scanning tunneling microscopy (STM) experiment reports the observation of a charge-density wave (CDW) with a period of approximately 8a in the halo region surrounding the vortex core, in striking contrast to the approximately 4a period CDWs that are commonly observed in the cuprates. Inspired by this work, we study a model where a bidirectional pair-density wave (PDW) with period 8 is at play. This further divides into two classes: (1) where the PDW is a competing state of the d -wave superconductor and can exist only near the vortex core where the d -wave order is suppressed and (2) where the PDW is the primary order, the so-called "mother state" that persists with strong phase fluctuations to high temperature and high magnetic field and lies behind the pseudogap phenomenology. We study the charge-density wave structures near the vortex core in these models. We emphasize the importance of the phase winding of the d -wave order parameter. The PDW can be pinned by the vortex core due to this winding and become static. Furthermore, the period-8 CDW inherits the properties of this winding, which gives rise to a special feature of the Fourier transform peak, namely, it is split in certain directions. There is also a line of zeros in the inverse Fourier transform of filtered data. We propose that these are key experimental signatures that can distinguish between the PDW-driven scenario from the more mundane option that the period-8 CDW is primary. We discuss the pro's and con's of the options considered above. Finally, we attempt to place the STM experiment in the broader context of pseudogap physics of underdoped cuprates and relate this observation to the unusual properties of x-ray scattering data on CDW carried out to very high magnetic field.

  20. Nuclear symmetry energy in density dependent hadronic models

    International Nuclear Information System (INIS)

    Haddad, S.

    2008-12-01

    The density dependence of the symmetry energy and the correlation between parameters of the symmetry energy and the neutron skin thickness in the nucleus 208 Pb are investigated in relativistic Hadronic models. The dependency of the symmetry energy on density is linear around saturation density. Correlation exists between the neutron skin thickness in the nucleus 208 Pb and the value of the nuclear symmetry energy at saturation density, but not with the slope of the symmetry energy at saturation density. (author)

  1. Batteries. Higher energy density than gasoline?

    International Nuclear Information System (INIS)

    Fischer, Michael; Werber, Mathew; Schwartz, Peter V.

    2009-01-01

    The energy density of batteries is two orders of magnitude below that of liquid fuels. However, this information alone cannot be used to compare batteries to liquid fuels for automobile energy storage media. Because electric motors have a higher energy conversion efficiency and lower mass than combustion engines, they can provide a higher deliverable mechanical energy density than internal combustion for most transportation applications. (author)

  2. On exact and approximate exchange-energy densities

    DEFF Research Database (Denmark)

    Springborg, Michael; Dahl, Jens Peder

    1999-01-01

    Based on correspondence rules between quantum-mechanical operators and classical functions in phase space we construct exchange-energy densities in position space. Whereas these are not unique but depend on the chosen correspondence rule, the exchange potential is unique. We calculate this exchange......-energy density for 15 closed-shell atoms, and compare it with kinetic- and Coulomb-energy densities. It is found that it has a dominating local-density character, but electron-shell effects are recognizable. The approximate exchange-energy functionals that have been proposed so far are found to account only...

  3. SURFACE SYMMETRY ENERGY OF NUCLEAR ENERGY DENSITY FUNCTIONALS

    Energy Technology Data Exchange (ETDEWEB)

    Nikolov, N; Schunck, N; Nazarewicz, W; Bender, M; Pei, J

    2010-12-20

    We study the bulk deformation properties of the Skyrme nuclear energy density functionals. Following simple arguments based on the leptodermous expansion and liquid drop model, we apply the nuclear density functional theory to assess the role of the surface symmetry energy in nuclei. To this end, we validate the commonly used functional parametrizations against the data on excitation energies of superdeformed band-heads in Hg and Pb isotopes, and fission isomers in actinide nuclei. After subtracting shell effects, the results of our self-consistent calculations are consistent with macroscopic arguments and indicate that experimental data on strongly deformed configurations in neutron-rich nuclei are essential for optimizing future nuclear energy density functionals. The resulting survey provides a useful benchmark for further theoretical improvements. Unlike in nuclei close to the stability valley, whose macroscopic deformability hangs on the balance of surface and Coulomb terms, the deformability of neutron-rich nuclei strongly depends on the surface-symmetry energy; hence, its proper determination is crucial for the stability of deformed phases of the neutron-rich matter and description of fission rates for r-process nucleosynthesis.

  4. Calculations of nuclear energies using the energy density formalism

    International Nuclear Information System (INIS)

    Pu, W.W.T.

    1975-01-01

    The energy density formalism (EDF) is used to investigate two problems. In this formalism the energy of the nucleus is expressed as a functional of its density. The nucleus energy is obtained by minimizing the functional with respect to the density. The first problem has to do with the stability of nuclei having shapes of different degrees of central depression (bubble shapes). It is shown that the bubble shapes are energetically favorable only for unrealistically large nuclei. Particularly, the super heavy nucleus that has been suggested (Z = 114, N = 184) prefers a shape with constant central density. These results are in good agreement with earlier calculations using the liquid drop model. The second problem concerns an anomaly detected experimentally in the isotope shift of mercury. The isotope shifts among a long chain of mercury isotopes show a sudden change as the neutron number is reduced. In particular, the experimental result suggests that the effective size of the charge distributions of 183 Hg and 185 Hg are as large as that of 196 Hg. Such sudden changes in other nuclei have been attributed to a sudden onset of permanent quadruple deformation. In the case of mercury there is no experimental evidence for deformed shapes. It was, therefore, suggested that the proton distribution might develop a central depression in the lighter isotopes. The EDF is used to investigate the mercury isotope shift anomaly following the aforementioned suggestion. Specifically, nucleon densities with different degrees of central depression are generated. Energies corresponding to these densities are obtained. To allow for shell effects, nucleon densities are obtained from single-particle wave functions. Calculations are made for a few mercury isotopes, especially for 184 Hg. The results are that in all cases the energy is lower for densities corresponding to a solid spherical shape

  5. Massive lepton pairs as a prompt photon surrogate

    International Nuclear Information System (INIS)

    Berger L, Edmond; Gordon E, Lionel; Klasen, Michael

    1998-01-01

    The authors discuss the transverse momentum distribution for the production of massive lepton-pairs in hadron reactions at fixed target and collider energies within the context of next-to-leading order perturbative quantum chromodynamics. For values of the transverse momentum Q T greater than the pair mass Q, Q T > Q, they show that the differential cross section is dominated by subprocesses initiated by incident gluons. Massive lepton-pair differential cross sections are an advantageous source of constraints on the gluon density, free from the experimental and theoretical complications of photon isolation that beset studies of prompt photon production. They compare calculations with data and provide predictions for the differential cross section as a function of Q T in proton-antiproton reactions at center-of-mass energies of 1.8 TeV, and in proton-nucleon reactions at fixed target and LHC energies

  6. Galaxy halo expansions: a new biorthogonal family of potential-density pairs

    Science.gov (United States)

    Lilley, Edward J.; Sanders, Jason L.; Evans, N. Wyn; Erkal, Denis

    2018-05-01

    Efficient expansions of the gravitational field of (dark) haloes have two main uses in the modelling of galaxies: first, they provide a compact representation of numerically constructed (or real) cosmological haloes, incorporating the effects of triaxiality, lopsidedness or other distortion. Secondly, they provide the basis functions for self-consistent field expansion algorithms used in the evolution of N-body systems. We present a new family of biorthogonal potential-density pairs constructed using the Hankel transform of the Laguerre polynomials. The lowest order density basis functions are double-power-law profiles cusped like ρ ˜ r-2+1/α at small radii with asymptotic density fall-off like ρ ˜ r-3-1/(2α). Here, α is a parameter satisfying α ≥ 1/2. The family therefore spans the range of inner density cusps found in numerical simulations, but has much shallower - and hence more realistic - outer slopes than the corresponding members of the only previously known family deduced by Zhao and exemplified by Hernquist & Ostriker. When α = 1, the lowest order density profile has an inner density cusp of ρ ˜ r-1 and an outer density slope of ρ ˜ r-3.5, similar to the famous Navarro, Frenk & White (NFW) model. For this reason, we demonstrate that our new expansion provides a more accurate representation of flattened NFW haloes than the competing Hernquist-Ostriker expansion. We utilize our new expansion by analysing a suite of numerically constructed haloes and providing the distributions of the expansion coefficients.

  7. Predictors of Dietary Energy Density among Preschool Aged Children

    Directory of Open Access Journals (Sweden)

    Nilmani N.T. Fernando

    2018-02-01

    Full Text Available Childhood obesity is a global problem with many contributing factors including dietary energy density (DED. This paper aims to investigate potential predictors of DED among preschool aged children in Victoria, Australia. Secondary analysis of longitudinal data for 209 mother–child pairs from the Melbourne Infant Feeding, Activity and Nutrition Trial was conducted. Data for predictors (maternal child feeding and nutrition knowledge, maternal dietary intake, home food availability, socioeconomic status were obtained through questionnaires completed by first-time mothers when children were aged 4 or 18 months. Three 24-h dietary recalls were completed when children were aged ~3.5 years. DED was calculated utilizing three methods: “food only”, “food and dairy beverages”, and “food and all beverages”. Linear regression analyses were conducted to identify associations between predictors and these three measures of children’s DED. Home availability of fruits (β: −0.82; 95% CI: −1.35, −0.29, p = 0.002 for DEDfood; β: −0.42; 95% CI: −0.82, −0.02, p = 0.041 for DEDfood+dairy beverages and non-core snacks (β: 0.11; 95% CI: 0.02, 0.20, p = 0.016 for DEDfood; β: 0.09; 95% CI: 0.02, 0.15, p = 0.010 for DEDfood+dairy beverages were significantly associated with two of the three DED measures. Providing fruit at home early in a child’s life may encourage the establishment of healthful eating behaviors that could promote a diet that is lower in energy density later in life. Home availability of non-core snacks is likely to increase the energy density of preschool children’s diets, supporting the proposition that non-core snack availability at home should be limited.

  8. High Energy Density Laboratory Astrophysics

    CERN Document Server

    Lebedev, Sergey V

    2007-01-01

    During the past decade, research teams around the world have developed astrophysics-relevant research utilizing high energy-density facilities such as intense lasers and z-pinches. Every two years, at the International conference on High Energy Density Laboratory Astrophysics, scientists interested in this emerging field discuss the progress in topics covering: - Stellar evolution, stellar envelopes, opacities, radiation transport - Planetary Interiors, high-pressure EOS, dense plasma atomic physics - Supernovae, gamma-ray bursts, exploding systems, strong shocks, turbulent mixing - Supernova remnants, shock processing, radiative shocks - Astrophysical jets, high-Mach-number flows, magnetized radiative jets, magnetic reconnection - Compact object accretion disks, x-ray photoionized plasmas - Ultrastrong fields, particle acceleration, collisionless shocks. These proceedings cover many of the invited and contributed papers presented at the 6th International Conference on High Energy Density Laboratory Astrophys...

  9. Differential bremsstrahlung and pair production cross sections at high energies

    International Nuclear Information System (INIS)

    Olsen, Haakon A.

    2003-01-01

    Detailed differential cross sections for high energy bremsstrahlung and pair production are derived with specific attention to the differences between the two processes, which are considerable. For the integrated cross sections, which are the only cross sections specifically known until now, the final state integration theorem guarantees that the exact cross section formulas can be exchanged between bremsstrahlung and pair production by the same substitution rules as for the Born-approximation Bethe-Heitler cross sections, for any amount of atomic screening. In fact the theorem states that the Coulomb corrections to the integrated bremsstrahlung and pair production cross sections are identical for any amount of screening. The analysis of the basic differential cross sections leads to fundamental physical differences between bremsstrahlung and pair production. Coulomb corrections occur for pair production in the strong electric field of the atom for 'large' momentum transfer of the order of mc. For bremsstrahlung, on the other hand, the Coulomb corrections take place at a 'large' distance from the atom of the order of ((ℎ/2π)/mc)ε, with a 'small' momentum transfer mc/ε, where ε is the initial electron energy in units of mc 2 . And the Coulomb corrections can be large, of the order of larger than (Z/137) 2 , which is considerably larger than the integrated cross section corrections

  10. Drell-Yan lepton pair production at high energies in the k{sub T}-factorization approach

    Energy Technology Data Exchange (ETDEWEB)

    Lipatov, A.V.; Malyshev, M.A.; Zotov, N.P. [M.V. Lomonosov Moscow State Univ. (Russian Federation). D.V. Skobeltsyn Inst. of Nuclear Physics

    2011-11-15

    In the framework of the k{sub T}-factorization approach, the production of unpolarized Drell-Yan lepton pair at high energies is studied. The consideration is based on the O({alpha}) and O({alpha}{alpha}{sub s}) off-shell partonic matrix elements with virtual photon {gamma}{sup *} and Z boson exchange. The calculations include leptonic decays of Z bosons with full spin correlations as well as {gamma}{sup *}-Z interference. The unintegrated parton densities in a proton are determined by the Kimber-Martin-Ryskin prescription. Our numerical predictions are compared with the data taken by the D diameter, CDF and CMS collaborations at the Tevatron and LHC energies. Special attention is put on the specific angular distributions measured very recently by the CDF collaboration for the first time. (orig.)

  11. Fluctuations in transverse energy and multiplicity, energy densities, and neutral pion spectra in nucleus-nucleus collissions at 200 GeV/nucleon

    International Nuclear Information System (INIS)

    Plasil, F.; Albrecht, R.; Awes, T.C.

    1989-01-01

    The main goal of the CERN heavy-ion experiments is the search for an indication that the predicted state of deconfined quarks and gluons, the quark-gluon plasma (QGP), has been produced. The quantity most crucial to the probability of QGP formation is the thermalized energy density attained during the heavy-ion reaction. The amount of energy radiated transverse to the beam direction is the experimental quantity which is believed to be a measure of the amount of energy deposition in the reaction, and hence to reflect the energy density attained. In this presentation we consider the systematics of transverse energy production at CERN SPS energies, and we use the results to make estimates, under various assumptions, of attained energy densities. Measurements of direct photons and lepton pairs are considered to be among the most promising methods for studies of the QGP. In contrast to hadrons, direct photons are not expected to undergo any interactions after their creation. The WA80 collaboration has undertaken the measurement of direct photons, which is a difficult task due to the presence of a high background of photons from the decay of neutral pions. The π 0 spectra themselves, however, provide us with the opportunity to study the excited reaction zone during the hadronization phase. We present here measurements of neutral pions produced in 16 O + Au collisions at 200 GeV/nucleon. 22 refs., 11 figs

  12. Importance of interlayer pair tunneling: A variational perspective

    International Nuclear Information System (INIS)

    Medhi, Amal; Basu, Saurabh

    2011-01-01

    We study the effect of interlayer pair tunneling in a bilayer superconductor where each layer is described by a two dimensional t-J model and the two layers are connected by the Josephson pair tunneling term. We study this model using a grand canonical variational Monte Carlo (GVMC) method, for which we develop a new algorithm to perform Monte Carlo simulation of a system with fluctuating particle number. The variational wavefunction is taken to be the product of two Gutzwiller projected d-wave BCS wavefunctions with variable particle densities, one for each layer. We calculate the energy of the above state as a function of the d-wave superconducting gap parameter, Δ. We find that the interlayer pair tunneling energy, E perpendicular shows interesting variation with Δ. E perpendicular tends to enhance the optimal value of Δ, thereby the superconducting pairing. However the magnitude of the tunneling energy is found to be too small to have any appreciable effect on the physical properties. While the result is supported by early experiments and hence may appear known to the community, the current work presents a new approach to the problem and confirms the diminished role of interlayer pair tunneling by directly calculating its contribution to superconducting condensation energy.

  13. Top quark pair production and calorimeter energy resolution studies at a future collider experiment

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, Katja

    2012-03-27

    This thesis is focused on detector concepts and analyses investigated at a future linear electron positron collider. For precision measurements at such a collider, the CALICE collaboration develops imaging calorimeters, which are characterized by a fine granularity. CALICE has constructed prototypes of several design options for electromagnetic and hadronic calorimeters and has successfully operated these detectors during combined test beam programs at DESY, CERN and Fermilab. To improve the hadronic energy reconstruction and energy resolution of a hadron calorimeter prototype with analog readout three software compensation techniques are presented in this thesis, of which one is a local and two are global software compensation approaches. One method is based on a neural network to optimize the energy reconstruction, while two are energy weighting techniques, depending on the energy density. Weight factors are extracted from and applied to simulated and test beam data and result in an average energy resolution improvement of 15 - 25% compared to a reconstruction without software compensation. Whether such software compensation techniques are also applicable to a detector concept for a future linear electron positron collider is studied in the second part of this thesis. Simulated data, two different hadronic detector models and a local software compensation technique are used for this study. The energy resolutions for single hadrons and for jets are presented with and without software compensation. In the third part of this thesis, a study on top quark pair production at a center-of-mass energy of 500 GeV at the proposed electron positron collider CLIC is presented. The analysis is based on full detector simulations, including realistic background contributions dominated by two photon processes. The mass and width of the top quark are studied in fully-hadronic and semi-leptonic decays of top quark pairs using event samples of signal and Standard Model background

  14. Top quark pair production and calorimeter energy resolution studies at a future collider experiment

    International Nuclear Information System (INIS)

    Seidel, Katja

    2012-01-01

    This thesis is focused on detector concepts and analyses investigated at a future linear electron positron collider. For precision measurements at such a collider, the CALICE collaboration develops imaging calorimeters, which are characterized by a fine granularity. CALICE has constructed prototypes of several design options for electromagnetic and hadronic calorimeters and has successfully operated these detectors during combined test beam programs at DESY, CERN and Fermilab. To improve the hadronic energy reconstruction and energy resolution of a hadron calorimeter prototype with analog readout three software compensation techniques are presented in this thesis, of which one is a local and two are global software compensation approaches. One method is based on a neural network to optimize the energy reconstruction, while two are energy weighting techniques, depending on the energy density. Weight factors are extracted from and applied to simulated and test beam data and result in an average energy resolution improvement of 15 - 25% compared to a reconstruction without software compensation. Whether such software compensation techniques are also applicable to a detector concept for a future linear electron positron collider is studied in the second part of this thesis. Simulated data, two different hadronic detector models and a local software compensation technique are used for this study. The energy resolutions for single hadrons and for jets are presented with and without software compensation. In the third part of this thesis, a study on top quark pair production at a center-of-mass energy of 500 GeV at the proposed electron positron collider CLIC is presented. The analysis is based on full detector simulations, including realistic background contributions dominated by two photon processes. The mass and width of the top quark are studied in fully-hadronic and semi-leptonic decays of top quark pairs using event samples of signal and Standard Model background

  15. Combinatorial nuclear level-density model

    International Nuclear Information System (INIS)

    Uhrenholt, H.; Åberg, S.; Dobrowolski, A.; Døssing, Th.; Ichikawa, T.; Möller, P.

    2013-01-01

    A microscopic nuclear level-density model is presented. The model is a completely combinatorial (micro-canonical) model based on the folded-Yukawa single-particle potential and includes explicit treatment of pairing, rotational and vibrational states. The microscopic character of all states enables extraction of level-distribution functions with respect to pairing gaps, parity and angular momentum. The results of the model are compared to available experimental data: level spacings at neutron separation energy, data on total level-density functions from the Oslo method, cumulative level densities from low-lying discrete states, and data on parity ratios. Spherical and deformed nuclei follow basically different coupling schemes, and we focus on deformed nuclei

  16. Isovector pairing effect on the particle-number projection two-proton separation energy

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari, Djamila; Kerrouchi, Slimane [Laboratoire de Physique Theorique, Faculte de Physique, Algiers (Algeria); Fellah, Mohamed; Allal, Nassima-Hosni [Laboratoire de Physique Theorique, Faculte de Physique, Algiers (Algeria); Centre de Recherche Nucleaire d' Alger, Comena, Algiers (Algeria)

    2009-07-01

    The two-proton separation energy is studied by performing a particle-number projection with and without inclusion of the isovector neutron-proton (np) pairing correlations. It is numerically evaluated for even-even rare-earth nuclei such that the np pairing parameter is non-zero. It is shown that the two-proton separation energy values calculated using the two approaches join, for almost all the considered elements, for the highest values of (N-Z). However, the results including the np pairing correlations are closest to the experimental data when available. Moreover, the two methods lead to the same prediction of the two-proton drip-line position, except for the Dysprosium and the Tungsten.

  17. Microscopic description of fission in odd-mass uranium and plutonium nuclei with the Gogny energy density functional

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Guzman, R. [Kuwait University, Physics Department, Kuwait (Kuwait); Robledo, L.M. [Universidad Autonoma de Madrid, Departamento de Fisica Teorica, Madrid (Spain); Universidad Politecnica de Madrid, Center for Computational Simulation, Boadilla del Monte (Spain)

    2017-12-15

    The parametrization D1M of the Gogny energy density functional is used to study fission in the odd-mass Uranium and Plutonium isotopes with A = 233,.., 249 within the framework of the Hartree-Fock-Bogoliubov (HFB) Equal Filling Approximation (EFA). Ground state quantum numbers and deformations, pairing energies, one-neutron separation energies, barrier heights and fission isomer excitation energies are given. Fission paths, collective masses and zero point rotational and vibrational quantum corrections are used to compute the systematic of the spontaneous fission half-lives t{sub SF}, the masses and charges of the fission fragments as well as their intrinsic shapes. Although there exits a strong variance of the predicted fission rates with respect to the details involved in their computation, it is shown that both the specialization energy and the pairing quenching effects, taken into account fully variationally within the HFB-EFA blocking scheme, lead to larger spontaneous fission half-lives in odd-mass U and Pu nuclei as compared with the corresponding even-even neighbors. It is shown that modifications of a few percent in the strengths of the neutron and proton pairing fields can have a significant impact on the collective masses leading to uncertainties of several orders of magnitude in the predicted t{sub SF} values. Alpha-decay lifetimes have also been computed using a parametrization of the Viola-Seaborg formula. (orig.)

  18. Glucose detection in a highly scattering medium with diffuse photon-pair density wave

    Directory of Open Access Journals (Sweden)

    Li-Ping Yu

    2017-01-01

    Full Text Available We propose a novel optical method for glucose measurement based on diffuse photon-pair density wave (DPPDW in a multiple scattering medium (MSM where the light scattering of photon-pair is induced by refractive index mismatch between scatters and phantom solution. Experimentally, the DPPDW propagates in MSM via a two-frequency laser (TFL beam wherein highly correlated pairs of linear polarized photons are generated. The reduced scattering coefficient μ2s′ and absorption coefficient μ2a of DPPDW are measured simultaneously in terms of the amplitude and phase measurements of the detected heterodyne signal under arrangement at different distances between the source and detection fibers in MSM. The results show that the sensitivity of glucose detection via glucose-induced change of reduced scattering coefficient (δμ2s′ is 0.049%mM−1 in a 1% intralipid solution. In addition, the linear range of δμ2s′ vs glucose concentration implies that this DPPDW method can be used to monitor glucose concentration continuously and noninvasively subcutaneously.

  19. N-representability of the Jastrow wave function pair density of the lowest-order.

    Science.gov (United States)

    Higuchi, Katsuhiko; Higuchi, Masahiko

    2017-08-08

    Conditions for the N-representability of the pair density (PD) are needed for the development of the PD functional theory. We derive sufficient conditions for the N-representability of the PD that is calculated from the Jastrow wave function within the lowest order. These conditions are used as the constraints on the correlation function of the Jastrow wave function. A concrete procedure to search the suitable correlation function is also presented.

  20. High density energy storage capacitor

    International Nuclear Information System (INIS)

    Whitham, K.; Howland, M.M.; Hutzler, J.R.

    1979-01-01

    The Nova laser system will use 130 MJ of capacitive energy storage and have a peak power capability of 250,000 MW. This capacitor bank is a significant portion of the laser cost and requires a large portion of the physical facilities. In order to reduce the cost and volume required by the bank, the Laser Fusion Program funded contracts with three energy storage capacitor producers: Aerovox, G.E., and Maxwell Laboratories, to develop higher energy density, lower cost energy storage capacitors. This paper describes the designs which resulted from the Aerovox development contract, and specifically addresses the design and initial life testing of a 12.5 kJ, 22 kV capacitor with a density of 4.2 J/in 3 and a projected cost in the range of 5 cents per joule

  1. Research on high energy density plasmas and applications

    International Nuclear Information System (INIS)

    1999-01-01

    Recently, technologies on lasers, accelerators, and pulse power machines have been significantly advanced and input power density covers the intensity range from 10 10 W/cm 2 to higher than 10 20 W/cm 2 . As the results, high pressure gas and solid targets can be heated up to very high temperature to create hot dense plasmas which have never appeared on the earth. The high energy density plasmas opened up new research fields such as inertial confinement fusion, high brightness X-ray radiation sources, interiors of galactic nucleus,supernova, stars and planets, ultra high pressure condensed matter physics, plasma particle accelerator, X-ray laser, and so on. Furthermore, since these fields are intimately connected with various industrial sciences and technologies, the high energy density plasma is now studied in industries, government institutions, and so on. This special issue of the Journal of Plasma Physics and Nuclear Fusion Research reviews the high energy density plasma science for the comprehensive understanding of such new fields. In May, 1998, the review committee for investigating the present status and the future prospects of high energy density plasma science was established in the Japan Society of Plasma Science and Nuclear Fusion Research. We held three committee meetings to discuss present status and critical issues of research items related to high energy density plasmas. This special issue summarizes the understandings of the committee. This special issue consists of four chapters: They are Chapter 1: Physics important in the high energy density plasmas, Chapter 2: Technologies related to the plasma generation; drivers such as lasers, pulse power machines, particle beams and fabrication of various targets, Chapter 3: Plasma diagnostics important in high energy density plasma experiments, Chapter 4: A variety of applications of high energy density plasmas; X-ray radiation, particle acceleration, inertial confinement fusion, laboratory astrophysics

  2. Dietary energy density: Applying behavioural science to weight management.

    Science.gov (United States)

    Rolls, B J

    2017-09-01

    Studies conducted by behavioural scientists show that energy density (kcal/g) provides effective guidance for healthy food choices to control intake and promote satiety. Energy density depends upon a number of dietary components, especially water (0 kcal/g) and fat (9 kcal/g). Increasing the proportion of water or water-rich ingredients, such as vegetables or fruit, lowers a food's energy density. A number of studies show that when the energy density of the diet is reduced, both adults and children spontaneously decrease their ad libitum energy intake. Other studies show that consuming a large volume of a low-energy-dense food such as soup, salad, or fruit as a first course preload can enhance satiety and reduce overall energy intake at a meal. Current evidence suggests that energy density influences intake through a complex interplay of cognitive, sensory, gastrointestinal, hormonal and neural influences. Other studies that focus on practical applications show how the strategic incorporation of foods lower in energy density into the diet allows people to eat satisfying portions while improving dietary patterns. This review discusses studies that have led to greater understanding of the importance of energy density for food intake regulation and weight management.

  3. A pair density functional theory utilizing the correlated wave function

    International Nuclear Information System (INIS)

    Higuchi, M; Higuchi, K

    2009-01-01

    We propose a practical scheme for calculating the ground-state pair density (PD) by utilizing the correlated wave function. As the correlated wave function, we adopt a linear combination of the single Slater determinants that are constructed from the solutions of the initial scheme [Higuchi M and Higuchi K 2007 Physica B 387, 117]. The single-particle equation is derived by performing the variational principle within the set of PDs that are constructed from such correlated wave functions. Since the search region of the PD is substantially extended as compared with the initial scheme, it is expected that the present scheme can cover more correlation effects. The single-particle equation is practical, and may be easily applied to actual calculations.

  4. Comparison of three methods to reduce energy density. Effects on daily energy intake.

    Science.gov (United States)

    Williams, Rachel A; Roe, Liane S; Rolls, Barbara J

    2013-07-01

    Reductions in food energy density can decrease energy intake, but it is not known if the effects depend on the way that energy density is reduced. We investigated whether three methods of reducing energy density (decreasing fat, increasing fruit and vegetables, and adding water) differed in their effects on energy intake across the day. In a crossover design, 59 adults ate breakfast, lunch, and dinner in the laboratory once a week for 4 weeks. Across conditions, the entrées were either standard in energy density or were reduced in energy density by 20% using one of the three methods. Each meal included a manipulated entrée along with unmanipulated side dishes, and all foods were consumed ad libitum. Reducing the energy density of entrées significantly decreased daily energy intake compared to standard entrées (mean intake 2667 ± 77 kcal/day; 11,166 ± 322 kJ/day). The mean decrease was 396 ± 44 kcal/day (1658 ± 184 kJ/day) when fat was reduced, 308 ± 41 kcal/day (1290 ± 172 kJ/day) when fruit and vegetables were increased, and 230 ± 35 kcal/day (963 ± 147 kJ/day) when water was added. Daily energy intake was lower when fat was decreased compared to the other methods. These findings indicate that a variety of diet compositions can be recommended to reduce overall dietary energy density in order to moderate energy intake. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Majorana edge States in atomic wires coupled by pair hopping.

    Science.gov (United States)

    Kraus, Christina V; Dalmonte, Marcello; Baranov, Mikhail A; Läuchli, Andreas M; Zoller, P

    2013-10-25

    We present evidence for Majorana edge states in a number conserving theory describing a system of spinless fermions on two wires that are coupled by pair hopping. Our analysis is based on a combination of a qualitative low energy approach and numerical techniques using the density matrix renormalization group. In addition, we discuss an experimental realization of pair-hopping interactions in cold atom gases confined in optical lattices.

  6. DWBA differential and total pair production cross sections for intermediate energy photons

    International Nuclear Information System (INIS)

    Selvaraju, C.; Bhullar, A.S.; Sud, K.K.

    2001-01-01

    We present in this communication the theoretical differential and total cross section for electron-positron pair creation by intermediate energy photons (5.0-10.0 MeV) on different targets (Z=1, 30, 50, 68, 82 and 92). The computed cross sections are in distorted wave Born approximation (DWBA) in point Coulomb potential. The database of the differential and total pair production cross sections is presented in tabulated as well as in graphical form and the interpolation of differential cross sections for different atomic numbers, positron and photon energies is discussed

  7. Exchange-correlation energies of atoms from efficient density functionals: influence of the electron density

    Science.gov (United States)

    Tao, Jianmin; Ye, Lin-Hui; Duan, Yuhua

    2017-12-01

    The primary goal of Kohn-Sham density functional theory is to evaluate the exchange-correlation contribution to electronic properties. However, the accuracy of a density functional can be affected by the electron density. Here we apply the nonempirical Tao-Mo (TM) semilocal functional to study the influence of the electron density on the exchange and correlation energies of atoms and ions, and compare the results with the commonly used nonempirical semilocal functionals local spin-density approximation (LSDA), Perdew-Burke-Ernzerhof (PBE), Tao-Perdew-Staroverov-Scuseria (TPSS), and hybrid functional PBE0. We find that the spin-restricted Hartree-Fock density yields the exchange and correlation energies in good agreement with the Optimized Effective Potential method, particularly for spherical atoms and ions. However, the errors of these semilocal and hybrid functionals become larger for self-consistent densities. We further find that the quality of the electron density have greater effect on the exchange-correlation energies of kinetic energy density-dependent meta-GGA functionals TPSS and TM than on those of the LSDA and GGA, and therefore, should have greater influence on the performance of meta-GGA functionals. Finally, we show that the influence of the density quality on PBE0 is slightly reduced, compared to that of PBE, due to the exact mixing.

  8. Spin contamination analogy, Kramers pairs symmetry and spin density representations at the 2-component unrestricted Hartree-Fock level of theory

    KAUST Repository

    Bučinský, Lukáš

    2015-05-11

    "Kramers pairs symmetry breaking" is evaluated at the 2-component (2c) Kramers unrestricted and/or general complex Hartree-Fock (GCHF) level of theory, and its analogy with "spin contamination" at the 1-component (1c) unrestricted Hartree-Fock (UHF) level of theory is emphasized. The GCHF "Kramers pairs symmetry breaking" evaluation is using the square of overlaps between the set of occupied spinorbitals with the projected set of Kramers pairs. In the same fashion, overlaps between α and β orbitals are used in the evaluation of "spin contamination" at the UHF level of theory. In this manner, UHF Š2 expectation value is made formally extended to the GCHF case. The directly evaluated GCHF expectation value of the Š2 operator is considered for completeness. It is found that the 2c GCHF Kramers pairs symmetry breaking has a very similar extent in comparison to the 1c UHF spin contamination. Thus higher excited states contributions to the 1c and 2c unrestricted wave functions of open shell systems have almost the same extent and physical consequences. Moreover, it is formally shown that a single determinant wave function in the restricted open shell Kramers case has the expectation value of K2 operator equal to the negative number of open shell electrons, while the eigenvalue of K2 for the series of simple systems (H, He, He*-triplet, Li and Li*-quartet) are found to be equal to minus the square of the number of open shell electrons. The concept of unpaired electron density is extended to the GCHF regime and compared to UHF and restricted open shell Hartree-Fock spin density. The "collinear" and "noncollinear" analogs of spin density at the GCHF level of theory are considered as well. Spin contamination and/or Kramers pairs symmetry breaking, spin populations and spin densities are considered for H2O+, Cl, HCl+, phenoxyl radical (C6H5O) as well as for Cu, Cu2+, Fe and the [OsCl5(1H-pyrazole)]- anion. The 1c and 2c unpaired electron density representation is found

  9. Experimental determination of the average energy necessary for the production of an ion pair in air

    International Nuclear Information System (INIS)

    Guiho, J.P.; Simoen, J.P.

    1975-01-01

    The determination of the average energy Wbarsub(a) necessary to form an ion pair in air in a 60 Co beam (which is one of the French primary references in dosimetry) is obtained from measurements of the exposure and absorbed doses from the beam in the center of a graphite disc. The differential flux density of the beam having been measured the experimental value of Wbarsub(a) is obtained for a mean real photon energy. The so determined value of Wbarsub(a) in dry air is: Wbarsub(a) = 33,96 +-0.34 JC -1 for Ebar = 1150 keV. This result is then compared to different published values. From this comparison the importance of different correcting terms such as the air humidity correction and the carbon/air stopping power ratio, which constitutes the main source of uncertainty, are considered. (author)

  10. Systematics of the level density parameters

    International Nuclear Information System (INIS)

    Ignatyuk, A.V.; Istekov, K.K.; Smirenkin, G.N.

    1977-01-01

    The excitation energy dependence of nucleus energy-level density is phenomenologically systematized in terms of the Fermi gas model. The analysis has been conducted in the atomic mass number range of A(>=)150, where the collective effects are mostly pronounced. The density parameter a(U) is obtained using data on neutron resonances. To depict energy spectra of nuclear states in the Fermi gas model (1) the contributions from collective rotational and vibrational modes (2), as well as from pair correlations (3) are also taken into account. It is shown, that at excitation energies close to the neutron binding energy all three systematics of a(U) yield practically the same energy-level densities. At high energies only the (2) and (3) systematics are valid, and at energies lower than the neutron binding energy only the last systematics will be adequate

  11. Comparison of three methods to reduce energy density: effects on daily energy intake

    OpenAIRE

    Williams, Rachel A.; Roe, Liane S.; Rolls, Barbara J.

    2013-01-01

    Reductions in food energy density can decrease energy intake, but it is not known if the effects depend on the way that energy density is reduced. We investigated whether three methods of reducing energy density (decreasing fat, increasing fruit and vegetables, and adding water) differed in their effects on energy intake across the day. In a crossover design, 59 adults ate breakfast, lunch, and dinner in the laboratory once a week for four weeks. Across conditions, the entrées were either sta...

  12. Pair correlations in nuclei

    International Nuclear Information System (INIS)

    Shimizu, Yoshifumi

    2009-01-01

    Except for the closed shell nuclei, almost all nuclei are in the superconducting state at their ground states. This well-known pair correlation in nuclei causes various interesting phenomena. It is especially to be noted that the pair correlation becomes weak in the excited states of nuclei with high angular momentum, which leads to the pair phase transition to the normal state in the high spin limit. On the other hand, the pair correlation becomes stronger in the nuclei with lower nucleon density than in those with normal density. In the region of neutron halo or skin state of unstable nuclei, this phenomenon is expected to be further enhanced to be observed compared to the ground state of stable nuclei. An overview of those interesting aspects caused via the pair correlation is presented here in the sections titled 'pair correlations in ground states', pair correlations in high spin states' and 'pair correlations in unstable nuclei' focusing on the high spin state. (S. Funahashi)

  13. High-Power-Density, High-Energy-Density Fluorinated Graphene for Primary Lithium Batteries

    Directory of Open Access Journals (Sweden)

    Guiming Zhong

    2018-03-01

    Full Text Available Li/CFx is one of the highest-energy-density primary batteries; however, poor rate capability hinders its practical applications in high-power devices. Here we report a preparation of fluorinated graphene (GFx with superior performance through a direct gas fluorination method. We find that the so-called “semi-ionic” C-F bond content in all C-F bonds presents a more critical impact on rate performance of the GFx in comparison with sp2 C content in the GFx, morphology, structure, and specific surface area of the materials. The rate capability remains excellent before the semi-ionic C-F bond proportion in the GFx decreases. Thus, by optimizing semi-ionic C-F content in our GFx, we obtain the optimal x of 0.8, with which the GF0.8 exhibits a very high energy density of 1,073 Wh kg−1 and an excellent power density of 21,460 W kg−1 at a high current density of 10 A g−1. More importantly, our approach opens a new avenue to obtain fluorinated carbon with high energy densities without compromising high power densities.

  14. Efficient and accurate local approximations to coupled-electron pair approaches: An attempt to revive the pair natural orbital method.

    Science.gov (United States)

    Neese, Frank; Wennmohs, Frank; Hansen, Andreas

    2009-03-21

    Coupled-electron pair approximations (CEPAs) and coupled-pair functionals (CPFs) have been popular in the 1970s and 1980s and have yielded excellent results for small molecules. Recently, interest in CEPA and CPF methods has been renewed. It has been shown that these methods lead to competitive thermochemical, kinetic, and structural predictions. They greatly surpass second order Moller-Plesset and popular density functional theory based approaches in accuracy and are intermediate in quality between CCSD and CCSD(T) in extended benchmark studies. In this work an efficient production level implementation of the closed shell CEPA and CPF methods is reported that can be applied to medium sized molecules in the range of 50-100 atoms and up to about 2000 basis functions. The internal space is spanned by localized internal orbitals. The external space is greatly compressed through the method of pair natural orbitals (PNOs) that was also introduced by the pioneers of the CEPA approaches. Our implementation also makes extended use of density fitting (or resolution of the identity) techniques in order to speed up the laborious integral transformations. The method is called local pair natural orbital CEPA (LPNO-CEPA) (LPNO-CPF). The implementation is centered around the concepts of electron pairs and matrix operations. Altogether three cutoff parameters are introduced that control the size of the significant pair list, the average number of PNOs per electron pair, and the number of contributing basis functions per PNO. With the conservatively chosen default values of these thresholds, the method recovers about 99.8% of the canonical correlation energy. This translates to absolute deviations from the canonical result of only a few kcal mol(-1). Extended numerical test calculations demonstrate that LPNO-CEPA (LPNO-CPF) has essentially the same accuracy as parent CEPA (CPF) methods for thermochemistry, kinetics, weak interactions, and potential energy surfaces but is up to 500

  15. Are energy-dense foods really cheaper? Reexamining the relation between food price and energy density.

    Science.gov (United States)

    Lipsky, Leah M

    2009-11-01

    The inverse relation between energy density (kcal/g) and energy cost (price/kcal) has been interpreted to suggest that produce (fruit, vegetables) is more expensive than snacks (cookies, chips). The objective of this study was to show the methodologic weakness of comparing energy density with energy cost. The relation between energy density and energy cost was replicated in a random-number data set. Additionally, observational data were collected for produce and snacks from an online supermarket. Variables included total energy (kcal), total weight (g), total number of servings, serving size (g/serving), and energy density (kcal/g). Price measures included energy cost ($/kcal), total price ($), unit price ($/g), and serving price ($/serving). Two-tailed t tests were used to compare price measures by food category. Relations between energy density and price measures within food categories were examined with the use of Spearman rank correlation analysis. The relation between energy density and energy cost was shown to be driven by the algebraic properties of these variables. Food category was strongly correlated with both energy density and food price measures. Energy cost was higher for produce than for snacks. However, total price and unit price were lower for produce. Serving price and serving size were greater for produce than for snacks. Within food categories, energy density was uncorrelated with most measures of food price, except for a weak positive correlation with serving price within the produce category. The findings suggest the relation between energy density and food price is confounded by food category and depends on which measure of price is used.

  16. Condensation energy density in Bi-2212 superconductors

    International Nuclear Information System (INIS)

    Matsushita, Teruo; Kiuchi, Masaru; Haraguchi, Teruhisa; Imada, Takeki; Okamura, Kazunori; Okayasu, Satoru; Uchida, Satoshi; Shimoyama, Jun-ichi; Kishio, Kohji

    2006-01-01

    The relationship between the condensation energy density and the anisotropy parameter, γ a , has been derived for Bi-2212 superconductors in various anisotropic states by analysing the critical current density due to columnar defects introduced by heavy ion irradiation. The critical current density depended on the size of the defects, determined by the kind and irradiation energy of the ions. A significantly large critical current density of 17.0 MA cm -2 was obtained at 5 K and 0.1 T even for the defect density of a matching field of 1 T in a specimen irradiated with iodine ions. The dependence of the critical current density on the size of the defects agreed well with the prediction from the summation theory of pinning forces, and the condensation energy density could be obtained consistently from specimens irradiated with different ions. The condensation energy density obtained increased with decreasing γ a over the entire range of measurement temperature, and reached about 60% of the value for the most three-dimensional Y-123 observed by Civale et al at 5 K. This gives the reason for the very strong pinning in Bi-2212 superconductors at low temperatures. The thermodynamic critical field obtained decreased linearly with increasing temperature and extrapolated to zero at a certain characteristic temperature, T * , lower than the critical temperature, T c . T * , which seems to be associated with the superconductivity in the block layers, was highest for the optimally doped specimen. This shows that the superconductivity becomes more inhomogeneous as the doped state of a superconductor deviates from the optimum condition

  17. Energy density of marine pelagic fish eggs

    DEFF Research Database (Denmark)

    Riis-Vestergaard, J.

    2002-01-01

    Analysis of the literature on pelagic fish eggs enabled generalizations to be made of their energy densities, because the property of being buoyant in sea water appears to constrain the proximate composition of the eggs and thus to minimize interspecific variation. An energy density of 1.34 J mul......(-1) of total egg volume is derived for most species spawning eggs without visible oil globules. The energy density of eggs with oil globules is predicted by (σ) over cap = 1.34 + 40.61 x (J mul(-1)) where x is the fractional volume of the oil globule. (C) 2002 The Fisheries Society of the British...

  18. Laser fusion and high energy density science

    International Nuclear Information System (INIS)

    Kodama, Ryosuke

    2005-01-01

    High-power laser technology is now opening a variety of new fields of science and technology using laser-produced plasmas. The laser plasma is now recognized as one of the important tools for the investigation and application of matter under extreme conditions, which is called high energy density science. This chapter shows a variety of applications of laser-produced plasmas as high energy density science. One of the more attractive industrial and science applications is the generation of intense pulse-radiation sources, such as the generation of electro-magnetic waves in the ranges of EUV (Extreme Ultra Violet) to gamma rays and laser acceleration of charged particles. The laser plasma is used as an energy converter in this regime. The fundamental science applications of high energy density physics are shown by introducing laboratory astrophysics, the equation of state of high pressure matter, including warm dense matter and nuclear science. Other applications are also presented, such as femto-second laser propulsion and light guiding. Finally, a new systematization is proposed to explore the possibility of the high energy density plasma application, which is called high energy plasma photonics''. This is also exploration of the boundary regions between laser technology and beam optics based on plasma physics. (author)

  19. Symmetry Energy as a Function of Density and Mass

    International Nuclear Information System (INIS)

    Danielewicz, Pawel; Lee, Jenny

    2007-01-01

    Energy in nuclear matter is, in practice, completely characterized at different densities and asymmetries, when the density dependencies of symmetry energy and of energy of symmetric matter are specified. The density dependence of the symmetry energy at subnormal densities produces mass dependence of nuclear symmetry coefficient and, thus, can be constrained by that latter dependence. We deduce values of the mass dependent symmetry coefficients, by using excitation energies to isobaric analog states. The coefficient systematic, for intermediate and high masses, is well described in terms of the symmetry coefficient values of a a V = (31.5-33.5) MeV for the volume coefficient and a a S = (9-12) MeV for the surface coefficient. These two further correspond to the parameter values describing density dependence of symmetry energy, of L∼95 MeV and K sym ∼25 MeV

  20. Low energy level density and surface instabilities in heavy transition nuclei

    International Nuclear Information System (INIS)

    Wieclawik, W. de; Foucher, R.; Dionisio, J.S.; Vieu, C.; Hoglund, A.; Watzig, W.

    1975-01-01

    A statistical analysis of Au, Pt, Hg nuclear levels was performed with Ericson's method. The odd mass gold experimental number of levels distributions are compared to the theoretical distributions corresponding to vibrational (Alaga and Kisslinger-Sorensen) and rotational (Stephens, Meyer-ter-Vehn) models. The Alaga model gives the most complete description of 193 Au, 195 Au levels and fits the lowest part of Gilbert-Cameron high energy distributions (deduced from the statistical model and neutron capture data). The Ericson's method shows other interesting features of Pt and Hg isotopes (i.e. level density dependence on nuclear shape and pairing correlations, evidence for phase transitions). Consequently, this method is a useful tool for guiding experimental as well as theoretical investigations of transition nuclei [fr

  1. Quantitative Raman Measurement of the Evolution of the Cooper-pair Density with Doping in Bi2Sr2CaCu2O8+δ Superconductors

    International Nuclear Information System (INIS)

    Blanc, S.; Gu, G.; Gallais, Y.; Sacuto, A.; Cazayous, M.; Measson, M.A.; Wen, J.S.; Xu, Z.J.

    2009-01-01

    We report Raman measurements on Bi 2 Sr 2 CaCu 2 O 8+δ single crystals that allow us to quantitatively evaluate the doping dependence of the density of Cooper pairs in the superconducting state. We show that the drastic loss of Cooper pairs in the antinodal region as the doping level is reduced is concomitant with a deep alteration of the quasiparticles dynamic above T c and consistent with a pseudogap that competes with superconductivity. Our data also reveal that the overall density of Cooper pairs evolves with doping, distinctly from the superfluid density above the doping level p c = 0.2.

  2. COMBINATION OF DENSITY AND ENERGY MODULATION IN MICROBUNCHING ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Cheng Ying [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Li, Rui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-05-01

    Microbunching instability (MBI) has been one of the most challenging issues in the transport of high-brightness electron beams for modern recirculating or energy recovery linac machines. Recently we have developed and implemented a Vlasov solver [1] to calculate the microbunching gain for an arbitrary beamline lattice, based on the extension of existing theoretical formulation [2-4] for the microbunching amplification from an initial density perturbation to the final density modulation. For more thorough analyses, in addition to the case of (initial) density to (final) density amplification, we extend in this paper the previous formulation to more general cases, including energy to density, density to energy and energy to energy amplifications for a recirculation machine. Such semi-analytical formulae are then incorporated into our Vlasov solver, and qualitative agreement is obtained when the semi-analytical Vlasov results are compared with particle tracking simulation using ELEGANT [5].

  3. Toward Low-Cost, High-Energy Density, and High-Power Density Lithium-Ion Batteries

    Science.gov (United States)

    Li, Jianlin; Du, Zhijia; Ruther, Rose E.; AN, Seong Jin; David, Lamuel Abraham; Hays, Kevin; Wood, Marissa; Phillip, Nathan D.; Sheng, Yangping; Mao, Chengyu; Kalnaus, Sergiy; Daniel, Claus; Wood, David L.

    2017-09-01

    Reducing cost and increasing energy density are two barriers for widespread application of lithium-ion batteries in electric vehicles. Although the cost of electric vehicle batteries has been reduced by 70% from 2008 to 2015, the current battery pack cost (268/kWh in 2015) is still >2 times what the USABC targets (125/kWh). Even though many advancements in cell chemistry have been realized since the lithium-ion battery was first commercialized in 1991, few major breakthroughs have occurred in the past decade. Therefore, future cost reduction will rely on cell manufacturing and broader market acceptance. This article discusses three major aspects for cost reduction: (1) quality control to minimize scrap rate in cell manufacturing; (2) novel electrode processing and engineering to reduce processing cost and increase energy density and throughputs; and (3) material development and optimization for lithium-ion batteries with high-energy density. Insights on increasing energy and power densities of lithium-ion batteries are also addressed.

  4. High energy density propulsion systems and small engine dynamometer

    Science.gov (United States)

    Hays, Thomas

    2009-07-01

    Scope and Method of Study. This study investigates all possible methods of powering small unmanned vehicles, provides reasoning for the propulsion system down select, and covers in detail the design and production of a dynamometer to confirm theoretical energy density calculations for small engines. Initial energy density calculations are based upon manufacturer data, pressure vessel theory, and ideal thermodynamic cycle efficiencies. Engine tests are conducted with a braking type dynamometer for constant load energy density tests, and show true energy densities in excess of 1400 WH/lb of fuel. Findings and Conclusions. Theory predicts lithium polymer, the present unmanned system energy storage device of choice, to have much lower energy densities than other conversion energy sources. Small engines designed for efficiency, instead of maximum power, would provide the most advantageous method for powering small unmanned vehicles because these engines have widely variable power output, loss of mass during flight, and generate rotational power directly. Theoretical predictions for the energy density of small engines has been verified through testing. Tested values up to 1400 WH/lb can be seen under proper operating conditions. The implementation of such a high energy density system will require a significant amount of follow-on design work to enable the engines to tolerate the higher temperatures of lean operation. Suggestions are proposed to enable a reliable, small-engine propulsion system in future work. Performance calculations show that a mature system is capable of month long flight times, and unrefueled circumnavigation of the globe.

  5. Electron Density Profile Data Contains Virtual Height/Frequency Pairs from a Profile or Profiles (Composite Months) of Ionograms

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Electron Density Profile, N(h), data set contains both individual profiles and composite months. The data consist of virtual height/frequency pairs from a...

  6. Postmortem validation of breast density using dual-energy mammography

    Energy Technology Data Exchange (ETDEWEB)

    Molloi, Sabee, E-mail: symolloi@uci.edu; Ducote, Justin L.; Ding, Huanjun; Feig, Stephen A. [Department of Radiological Sciences, University of California, Irvine, California 92697 (United States)

    2014-08-15

    Purpose: Mammographic density has been shown to be an indicator of breast cancer risk and also reduces the sensitivity of screening mammography. Currently, there is no accepted standard for measuring breast density. Dual energy mammography has been proposed as a technique for accurate measurement of breast density. The purpose of this study is to validate its accuracy in postmortem breasts and compare it with other existing techniques. Methods: Forty postmortem breasts were imaged using a dual energy mammography system. Glandular and adipose equivalent phantoms of uniform thickness were used to calibrate a dual energy basis decomposition algorithm. Dual energy decomposition was applied after scatter correction to calculate breast density. Breast density was also estimated using radiologist reader assessment, standard histogram thresholding and a fuzzy C-mean algorithm. Chemical analysis was used as the reference standard to assess the accuracy of different techniques to measure breast composition. Results: Breast density measurements using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean algorithm, and dual energy were in good agreement with the measured fibroglandular volume fraction using chemical analysis. The standard error estimates using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean, and dual energy were 9.9%, 8.6%, 7.2%, and 4.7%, respectively. Conclusions: The results indicate that dual energy mammography can be used to accurately measure breast density. The variability in breast density estimation using dual energy mammography was lower than reader assessment rankings, standard histogram thresholding, and fuzzy C-mean algorithm. Improved quantification of breast density is expected to further enhance its utility as a risk factor for breast cancer.

  7. Postmortem validation of breast density using dual-energy mammography

    International Nuclear Information System (INIS)

    Molloi, Sabee; Ducote, Justin L.; Ding, Huanjun; Feig, Stephen A.

    2014-01-01

    Purpose: Mammographic density has been shown to be an indicator of breast cancer risk and also reduces the sensitivity of screening mammography. Currently, there is no accepted standard for measuring breast density. Dual energy mammography has been proposed as a technique for accurate measurement of breast density. The purpose of this study is to validate its accuracy in postmortem breasts and compare it with other existing techniques. Methods: Forty postmortem breasts were imaged using a dual energy mammography system. Glandular and adipose equivalent phantoms of uniform thickness were used to calibrate a dual energy basis decomposition algorithm. Dual energy decomposition was applied after scatter correction to calculate breast density. Breast density was also estimated using radiologist reader assessment, standard histogram thresholding and a fuzzy C-mean algorithm. Chemical analysis was used as the reference standard to assess the accuracy of different techniques to measure breast composition. Results: Breast density measurements using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean algorithm, and dual energy were in good agreement with the measured fibroglandular volume fraction using chemical analysis. The standard error estimates using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean, and dual energy were 9.9%, 8.6%, 7.2%, and 4.7%, respectively. Conclusions: The results indicate that dual energy mammography can be used to accurately measure breast density. The variability in breast density estimation using dual energy mammography was lower than reader assessment rankings, standard histogram thresholding, and fuzzy C-mean algorithm. Improved quantification of breast density is expected to further enhance its utility as a risk factor for breast cancer

  8. Nonlocal kinetic-energy-density functionals

    International Nuclear Information System (INIS)

    Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E.

    1996-01-01

    In this paper we present nonlocal kinetic-energy functionals T[n] within the average density approximation (ADA) framework, which do not require any extra input when applied to any electron system and recover the exact kinetic energy and the linear response function of a homogeneous system. In contrast with previous ADA functionals, these present good behavior of the long-range tail of the exact weight function. The averaging procedure for the kinetic functional (averaging the Fermi momentum of the electron gas, instead of averaging the electron density) leads to a functional without numerical difficulties in the calculation of extended systems, and it gives excellent results when applied to atoms and jellium surfaces. copyright 1996 The American Physical Society

  9. One-body density matrix and the momentum density in 4He and 3He

    International Nuclear Information System (INIS)

    Whitlock, P.A.; Panoff, R.M.

    1984-01-01

    The one-body density matrix and the momentum density for liquid and solid 4 He, determined from Green's Function Monte Carlo calculations using the HFDHE2 pair potential, are described. Values for the condensate fraction and the kinetic energy derived from these calculations are given and compared to recent experimental results. Preliminary results from variational Monte Carlo calculations on n(r) and n(k) for liquid 3 He are also reported

  10. Density and energy of supernova remnants

    Energy Technology Data Exchange (ETDEWEB)

    Canto, J [Manchester Univ. (UK). Dept. of Astronomy

    1977-12-01

    The effects of an interstellar magnetic field on the gas flow behind a strong shock front are considered. The ambient density and energy of supernova remnants are estimated from the intensity ratio of sulphur lines I(6717)/I(6731). It is found that, on average, the ambient density around galactic supernova remnants is 4 cm/sup -3/. The total energy appears to be the same for all supernova remnants (to within a factor = approximately 5). A mean value of 4 10/sup 51/ erg is found.

  11. Pair condensation and bound states in fermionic systems

    International Nuclear Information System (INIS)

    Sedrakian, Armen; Clark, John W.

    2006-01-01

    We study the finite temperature-density phase diagram of an attractive fermionic system that supports two-body (dimer) and three-body (trimer) bound states in free space. Using interactions characteristic for nuclear systems, we obtain the critical temperature T c2 for the superfluid phase transition and the limiting temperature T c3 for the extinction of trimers. The phase diagram features a Cooper-pair condensate in the high-density, low-temperature domain which, with decreasing density, crosses over to a Bose condensate of strongly bound dimers. The high-temperature, low-density domain is populated by trimers whose binding energy decreases toward the density-temperature domain occupied by the superfluid and vanishes at a critical temperature T c3 >T c2

  12. New aspects of high energy density plasma

    International Nuclear Information System (INIS)

    Hotta, Eiki

    2005-10-01

    The papers presented at the symposium on 'New aspects of high energy density plasma' held at National Institute for Fusion Science are collected in this proceedings. The papers reflect the present status and recent progress in the experiments and theoretical works on high energy density plasma produced by pulsed power technology. The 13 of the presented papers are indexed individually. (J.P.N.)

  13. Some features of excited states density matrix calculation and their pairing relations in conjugated systems

    International Nuclear Information System (INIS)

    Giambiagi, M.S. de; Giambiagi, M.

    1982-01-01

    Direct PPP-type calculations of self-consistent (SC) density matrices for excited states are described and the corresponding 'thawn' molecular orbitals (MO) are discussed. Special attention is addressed to particular solutions arising in conjugated systems of a certain symmetry, and to their chemical implications. The U(2) and U(3) algebras are applied respectively to the 4-electron and 6-electron cases: a natural separation of excited states in different cases follows. A simple approach to the convergence problem for excited states is given. The complementarity relations, an alternative formulation of the pairing theorem valid for heteromolecules and non-alternant systems, allow some fruitful experimental applications. Together with the extended pairing relations shown here, they may help to rationalize general trends. (Author) [pt

  14. Spectroscopy of metal "superatom" nanoclusters and high-Tc superconducting pairing

    Science.gov (United States)

    Halder, Avik; Kresin, Vitaly V.

    2015-12-01

    A unique property of metal nanoclusters is the "superatom" shell structure of their delocalized electrons. The electronic shell levels are highly degenerate and therefore represent sharp peaks in the density of states. This can enable exceptionally strong electron pairing in certain clusters composed of tens to hundreds of atoms. In a finite system, such as a free nanocluster or a nucleus, pairing is observed most clearly via its effect on the energy spectrum of the constituent fermions. Accordingly, we performed a photoionization spectroscopy study of size-resolved aluminum nanoclusters and observed a rapid rise in the near-threshold density of states of several clusters (A l37 ,44 ,66 ,68 ) with decreasing temperature. The characteristics of this behavior are consistent with compression of the density of states by a pairing transition into a high-temperature superconducting state with Tc≳100 K. This value exceeds that of bulk aluminum by two orders of magnitude. These results highlight the potential of novel pairing effects in size-quantized systems and the possibility to attain even higher critical temperatures by optimizing the particles' size and composition. As a new class of high-temperature superconductors, such metal nanocluster particles are promising building blocks for high-Tc materials, devices, and networks.

  15. Effects of the particle-number projection on the isovector pairing energy

    International Nuclear Information System (INIS)

    Allal, N.H.; Fellah, M.; Oudih, M.R.; Benhamouda, N.

    2006-01-01

    The usual neutron-proton BCS wave function is simultaneously projected on both the good neutron and proton numbers using a discrete projection operator. The projected energy of the system is deduced as a limit of rapidly convergent sequence. It is numerically studied for the N=Z nuclei of which ''experimental'' pairing gaps may be deduced from the experimental odd-even mass differences. It then appears that the particle-number fluctuation effect is even more important than in the case of pairing between like-particles. (orig.)

  16. A high energy density relaxor antiferroelectric pulsed capacitor dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Hwan Ryul; Lynch, Christopher S. [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles (UCLA), Los Angeles, California 90095 (United States)

    2016-01-14

    Pulsed capacitors require high energy density and low loss, properties that can be realized through selection of composition. Ceramic (Pb{sub 0.88}La{sub 0.08})(Zr{sub 0.91}Ti{sub 0.09})O{sub 3} was found to be an ideal candidate. La{sup 3+} doping and excess PbO were used to produce relaxor antiferroelectric behavior with slim and slanted hysteresis loops to reduce the dielectric hysteresis loss, to increase the dielectric strength, and to increase the discharge energy density. The discharge energy density of this composition was found to be 3.04 J/cm{sup 3} with applied electric field of 170 kV/cm, and the energy efficiency, defined as the ratio of the discharge energy density to the charging energy density, was 0.920. This high efficiency reduces the heat generated under cyclic loading and improves the reliability. The properties were observed to degrade some with temperature increase above 80 °C. Repeated electric field cycles up to 10 000 cycles were applied to the specimen with no observed performance degradation.

  17. Bremsstrahlung and pair production in crystals at very high energies

    International Nuclear Information System (INIS)

    Nikishov, A.I.

    1981-01-01

    The probabilities for bremsstrahlung and pair production in crystals are discussed under stringent condition when the trajectory of the high-energy electron crosses very many atoms of a crystal row (or plane). It is shown that for sufficiently long path in such conditions the probabilities are described by the formulas for these processes in a strong constant magnetic field exerting on electron the same deflection as the atom row. It turns out that for lead at energy approximately 10 12 eV the radiation length is shortened many hundred times. For greater energies the decrease of probabilities per unit length with increase of energy goes as W varies as Esup(-1/3)

  18. Nonlocal exchange and kinetic-energy density functionals for electronic systems

    International Nuclear Information System (INIS)

    Glossman, M.D.; Rubio, A.; Balbas, L.C.; Alonso, J.A.

    1992-01-01

    The nonlocal weighted density approximation (WDA) to the exchange and kinetic-energy functionals of many electron systems proposed several years ago by Alonso and Girifalco is used to compute, within the framework of density functional theory, the ground-state electronic density and total energy of noble gas atoms and of neutral jellium-like sodium clusters containing up to 500 atoms. These results are compared with analogous calculations using the well known Thomas-Fermi-Weizsacker-Dirac (TFWD) approximations for the kinetic (TFW) and exchange (D) energy density functionals. An outstanding improvement of the total and exchange energies, of the density at the nucleus and of the expectation values is obtained for atoms within the WDA scheme. For sodium clusters the authors notice a sizeable contribution of the nonlocal effects to the total energy and to the density profiles. In the limit of very large clusters these effects should affect the surface energy of the bulk metal

  19. Excitation energies with linear response density matrix functional theory along the dissociation coordinate of an electron-pair bond in N-electron systems

    International Nuclear Information System (INIS)

    Meer, R. van; Gritsenko, O. V.; Baerends, E. J.

    2014-01-01

    Time dependent density matrix functional theory in its adiabatic linear response formulation delivers exact excitation energies ω α and oscillator strengths f α for two-electron systems if extended to the so-called phase including natural orbital (PINO) theory. The Löwdin-Shull expression for the energy of two-electron systems in terms of the natural orbitals and their phases affords in this case an exact phase-including natural orbital functional (PILS), which is non-primitive (contains other than just J and K integrals). In this paper, the extension of the PILS functional to N-electron systems is investigated. With the example of an elementary primitive NO functional (BBC1) it is shown that current density matrix functional theory ground state functionals, which were designed to produce decent approximations to the total energy, fail to deliver a qualitatively correct structure of the (inverse) response function, due to essential deficiencies in the reconstruction of the two-body reduced density matrix (2RDM). We now deduce essential features of an N-electron functional from a wavefunction Ansatz: The extension of the two-electron Löwdin-Shull wavefunction to the N-electron case informs about the phase information. In this paper, applications of this extended Löwdin-Shull (ELS) functional are considered for the simplest case, ELS(1): one (dissociating) two-electron bond in the field of occupied (including core) orbitals. ELS(1) produces high quality ω α (R) curves along the bond dissociation coordinate R for the molecules LiH, Li 2 , and BH with the two outer valence electrons correlated. All of these results indicate that response properties are much more sensitive to deficiencies in the reconstruction of the 2RDM than the ground state energy, since derivatives of the functional with respect to both the NOs and the occupation numbers need to be accurate

  20. Determination of the LEP Beam Energy using Radiative Fermion-pair Events, 2004

    CERN Document Server

    Abbiendi, G; Åkesson, P F; Alexander, G; Allison, J; Amaral, P; Anagnostou, G; Anderson, K J; Asai, S; Axen, D A; Bailey, I; Barberio, E; Barillari, T; Barlow, R J; Batley, J Richard; Bechtle, P; Behnke, T; Bell, K W; Bell, P J; Bella, G; Bellerive, A; Benelli, G; Bethke, Siegfried; Biebel, O; Boeriu, O; Bock, P; Boutemeur, M; Braibant, S; Brown, R M; Burckhart, H J; Campana, S; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Ciocca, C; Csilling, A; Cuffiani, M; Dado, S; de Roeck, A; De Wolf, E A; Desch, Klaus; Dienes, B; Donkers, M; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Etzion, E; Fabbri, Franco Luigi; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Gagnon, P; Gary, J W; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giunta, M; Goldberg, J; Gross, E; Grunhaus, Jacob; Gruwé, M; Günther, P O; Sen-Gupta, A; Hajdu, C; Hamann, M; Hanson, G G; Harel, A; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, R J; Herten, G; Heuer, R D; Hill, J C; Hoffman, K; Horváth, D; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jovanovic, P; Junk, T R; Kanzaki, J; Karlen, Dean A; Kawagoe, K; Kawamoto, T; Keeler, R K; Kellogg, R G; Kennedy, B W; Kluth, S; Kobayashi, T; Kobel, M; Komamiya, S; Kramer, T; Krieger, P; Von Krogh, J; Kühl, T; Kupper, M; Lafferty, G D; Landsman, Hagar Yaël; Lanske, D; Lellouch, D; Letts, J; Levinson, L; Lillich, J; Lloyd, S L; Loebinger, F K; Lü, J; Ludwig, A; Ludwig, J; Mader, W; Marcellini, S; Martin, A J; Masetti, G; Mashimo, T; Mättig, P; McKenna, J A; McPherson, R A; Meijers, F; Menges, W; Merritt, F S; Mes, H; Meyer, N; Michelini, A; Mihara, S; Mikenberg, G; Miller, D J; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Nanjo, H; Neal, H A; Nisius, R; O'Neale, S W; Oh, A; Oreglia, M J; Orito, S; Pahl, C; Pásztor, G; Pater, J R; Pilcher, J E; Pinfold, J L; Plane, D E; Pooth, O; Przybycien, M B; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Roney, J M; Rossi, A M; Rozen, Y; Runge, K; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schieck, J; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Seuster, R; Shears, T G; Shen, B C; Sherwood, P; Skuja, A; Smith, A M; Sobie, R J; Söldner-Rembold, S; Spanó, F; Stahl, A; Strom, D; Ströhmer, R; Tarem, S; Tasevsky, M; Teuscher, R; Thomson, M A; Torrence, E; Toya, D; Tran, P; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvári, B; Vollmer, C F; Vannerem, P; Vertesi, R; Verzocchi, M; Voss, H; Vossebeld, Joost Herman; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Zer-Zion, D; Zivkovic, L

    2004-01-01

    We present a determination of the LEP beam energy using "radiative return" fermion-pair events recorded at centre-of-mass energies from 183 GeV to 209 GeV. We find no evidence of a disagreement between the OPAL data and the LEP Energy Workings Group's standard calibration. Including the energy- averaged 11 MeV uncertainty in the standard determination, the beam energy we obtain from the OPAL data is higher than that obtained from the LEP calibration by 0+-34(stat.)+-27(syst.)MeV

  1. Density dependence of the nuclear energy-density functional

    Science.gov (United States)

    Papakonstantinou, Panagiota; Park, Tae-Sun; Lim, Yeunhwan; Hyun, Chang Ho

    2018-01-01

    Background: The explicit density dependence in the coupling coefficients entering the nonrelativistic nuclear energy-density functional (EDF) is understood to encode effects of three-nucleon forces and dynamical correlations. The necessity for the density-dependent coupling coefficients to assume the form of a preferably small fractional power of the density ρ is empirical and the power is often chosen arbitrarily. Consequently, precision-oriented parametrizations risk overfitting in the regime of saturation and extrapolations in dilute or dense matter may lose predictive power. Purpose: Beginning with the observation that the Fermi momentum kF, i.e., the cubic root of the density, is a key variable in the description of Fermi systems, we first wish to examine if a power hierarchy in a kF expansion can be inferred from the properties of homogeneous matter in a domain of densities, which is relevant for nuclear structure and neutron stars. For subsequent applications we want to determine a functional that is of good quality but not overtrained. Method: For the EDF, we fit systematically polynomial and other functions of ρ1 /3 to existing microscopic, variational calculations of the energy of symmetric and pure neutron matter (pseudodata) and analyze the behavior of the fits. We select a form and a set of parameters, which we found robust, and examine the parameters' naturalness and the quality of resulting extrapolations. Results: A statistical analysis confirms that low-order terms such as ρ1 /3 and ρ2 /3 are the most relevant ones in the nuclear EDF beyond lowest order. It also hints at a different power hierarchy for symmetric vs. pure neutron matter, supporting the need for more than one density-dependent term in nonrelativistic EDFs. The functional we propose easily accommodates known or adopted properties of nuclear matter near saturation. More importantly, upon extrapolation to dilute or asymmetric matter, it reproduces a range of existing microscopic

  2. Search for the Hadroproduction of BbarB Pairs

    CERN Multimedia

    2002-01-01

    We propose an experiment to search for B$\\bar{B}$ pairs produced by dumping a total of~@C2~x~10|1|2~@p|- at 350~GeV/c in a target calorimeter of variable density. The sensitivity of the experiment will lie between 100 and 500~pb depending upon the B$\\bar{B}$ production mechanism. The B$\\bar{B}$ signal will be found among the events of the type .ce @p|-N @A @m@+@m@+ + X and @p|-N @A 3(4) @m + X. The requirement of at least one high p^T muon together with a large missing energy due to escaping neutrinos, strongly enhanc the signal to background ratio. The background, due to the production of @m|+@m|- pairs associated with a ``non-prompt'' muon from @p and K decay, will be measured directly extrapolating the results to an infinite target density. The experiment will use the muon spectrometer developed by the WA75 collaboration for the beauty search in emulsion, equipped with a target calorimeter especially designed to perform energy measurements under high rate conditions. The high sensitivity and the independen...

  3. Electrode/Dielectric Strip For High-Energy-Density Capacitor

    Science.gov (United States)

    Yen, Shiao-Ping S.

    1994-01-01

    Improved unitary electrode/dielectric strip serves as winding in high-energy-density capacitor in pulsed power supply. Offers combination of qualities essential for high energy density: high permittivity of dielectric layers, thinness, and high resistance to breakdown of dielectric at high electric fields. Capacitors with strip material not impregnated with liquid.

  4. Ultra-stiff metallic glasses through bond energy density design.

    Science.gov (United States)

    Schnabel, Volker; Köhler, Mathias; Music, Denis; Bednarcik, Jozef; Clegg, William J; Raabe, Dierk; Schneider, Jochen M

    2017-07-05

    The elastic properties of crystalline metals scale with their valence electron density. Similar observations have been made for metallic glasses. However, for metallic glasses where covalent bonding predominates, such as metalloid metallic glasses, this relationship appears to break down. At present, the reasons for this are not understood. Using high energy x-ray diffraction analysis of melt spun and thin film metallic glasses combined with density functional theory based molecular dynamics simulations, we show that the physical origin of the ultrahigh stiffness in both metalloid and non-metalloid metallic glasses is best understood in terms of the bond energy density. Using the bond energy density as novel materials design criterion for ultra-stiff metallic glasses, we are able to predict a Co 33.0 Ta 3.5 B 63.5 short range ordered material by density functional theory based molecular dynamics simulations with a high bond energy density of 0.94 eV Å -3 and a bulk modulus of 263 GPa, which is 17% greater than the stiffest Co-B based metallic glasses reported in literature.

  5. Alternative definitions of the frozen energy in energy decomposition analysis of density functional theory calculations.

    Science.gov (United States)

    Horn, Paul R; Head-Gordon, Martin

    2016-02-28

    In energy decomposition analysis (EDA) of intermolecular interactions calculated via density functional theory, the initial supersystem wavefunction defines the so-called "frozen energy" including contributions such as permanent electrostatics, steric repulsions, and dispersion. This work explores the consequences of the choices that must be made to define the frozen energy. The critical choice is whether the energy should be minimized subject to the constraint of fixed density. Numerical results for Ne2, (H2O)2, BH3-NH3, and ethane dissociation show that there can be a large energy lowering associated with constant density orbital relaxation. By far the most important contribution is constant density inter-fragment relaxation, corresponding to charge transfer (CT). This is unwanted in an EDA that attempts to separate CT effects, but it may be useful in other contexts such as force field development. An algorithm is presented for minimizing single determinant energies at constant density both with and without CT by employing a penalty function that approximately enforces the density constraint.

  6. Probing the density content of the nuclear symmetry energy

    Indian Academy of Sciences (India)

    Abstract. The nature of equation of state for the neutron star matter is crucially governed by the density dependence of the nuclear symmetry energy. We attempt to probe the behaviour of the nuclear symmetry energy around the saturation density by exploiting the empirical values for volume and surface symmetry energy ...

  7. Ultimate energy density of observable cold baryonic matter.

    Science.gov (United States)

    Lattimer, James M; Prakash, Madappa

    2005-03-25

    We demonstrate that the largest measured mass of a neutron star establishes an upper bound to the energy density of observable cold baryonic matter. An equation of state-independent expression satisfied by both normal neutron stars and self-bound quark matter stars is derived for the largest energy density of matter inside stars as a function of their masses. The largest observed mass sets the lowest upper limit to the density. Implications from existing and future neutron star mass measurements are discussed.

  8. Pair plasma relaxation time scales.

    Science.gov (United States)

    Aksenov, A G; Ruffini, R; Vereshchagin, G V

    2010-04-01

    By numerically solving the relativistic Boltzmann equations, we compute the time scale for relaxation to thermal equilibrium for an optically thick electron-positron plasma with baryon loading. We focus on the time scales of electromagnetic interactions. The collisional integrals are obtained directly from the corresponding QED matrix elements. Thermalization time scales are computed for a wide range of values of both the total-energy density (over 10 orders of magnitude) and of the baryonic loading parameter (over 6 orders of magnitude). This also allows us to study such interesting limiting cases as the almost purely electron-positron plasma or electron-proton plasma as well as intermediate cases. These results appear to be important both for laboratory experiments aimed at generating optically thick pair plasmas as well as for astrophysical models in which electron-positron pair plasmas play a relevant role.

  9. Full transverse-momentum spectra of low-mass Drell-Yan pairs at LHC energies

    CERN Document Server

    Fái, G; Zhang, X; Fai, George; Qiu, Jianwei; Zhang, Xiaofei

    2003-01-01

    The transverse momentum distribution of low-mass Drell-Yan pairs is calculated in QCD perturbation theory with all-order resummation. We argue that at LHC energies the results should be reliable for the entire transverse momentum range. We demonstrate that the transverse momentum distribution of low-mass Drell-Yan pairs is an advantageous source of constraints on the gluon distribution and its nuclear dependence.

  10. Negative vacuum energy densities and the causal diamond measure

    International Nuclear Information System (INIS)

    Salem, Michael P.

    2009-01-01

    Arguably a major success of the landscape picture is the prediction of a small, nonzero vacuum energy density. The details of this prediction depend in part on how the diverging spacetime volume of the multiverse is regulated, a question that remains unresolved. One proposal, the causal diamond measure, has demonstrated many phenomenological successes, including predicting a distribution of positive vacuum energy densities in good agreement with observation. In the string landscape, however, the vacuum energy density is expected to take positive and negative values. We find the causal diamond measure gives a poor fit to observation in such a landscape - in particular, 99.6% of observers in galaxies seemingly just like ours measure a vacuum energy density smaller than we do, most of them measuring it to be negative.

  11. 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.

  12. Moderate energy ions for high energy density physics experiments

    International Nuclear Information System (INIS)

    Grisham, L.R.

    2004-01-01

    This paper gives the results of a preliminary exploration of whether moderate energy ions (≅0.3-3 MeV/amu) could be useful as modest-cost drivers for high energy density physics experiments. It is found that if the target thickness is chosen so that the ion beam enters and then leaves the target in the vicinity of the peak of the dE/dX (stopping power) curve, high uniformity of energy deposition may be achievable while also maximizing the amount of energy per beam particle deposited within the target

  13. Foldable, High Energy Density Lithium Ion Batteries

    Science.gov (United States)

    Suresh, Shravan

    Lithium Ion Batteries (LIBs) have become ubiquitous owing to its low cost, high energy density and, power density. Due to these advantages, LIBs have garnered a lot of attention as the primary energy storage devices in consumer electronics and electric vehicles. Recent advances in the consumer electronics research and, the drive to reduce greenhouse gases have created a demand for a shape conformable, high energy density batteries. This thesis focuses on the aforementioned two aspects of LIBs: (a) shape conformability (b) energy density and provides potential solutions to enhance them. This thesis is divided into two parts viz. (i) achieving foldability in batteries and, (ii) improving its energy density. Conventional LIBs are not shape conformable due to two limitations viz. inelasticity of metallic foils, and delamination of the active materials while bending. In the first part of the thesis (in Chapter 3), this problem is solved by replacing metallic current collector with Carbon Nanotube Macrofilms (CNMs). CNMs are superelastic films comprising of porous interconnected nanotube network. Using Molecular Dynamics (MD) simulation, we found that in the presence of an interconnected nanotube network CNMs can be fully folded. This is because the resultant stress due to bending and, the effective bending angle at the interface is reduced due to the network of nanotubes. Hence, unlike an isolated nanotube (which ruptures beyond 120 degrees of bending), a network of nanotubes can be completely folded. Thus, by replacing metallic current collector foils with CNMs, the flexibility limitation of a conventional LIB can be transcended. The second part of this thesis focusses on enhancing the energy density of LIBs. Two strategies adopted to achieve this goal are (a) removing the dead weight of the batteries, and (b) incorporating high energy density electrode materials. By incorporating CNMs, the weight of the batteries was reduced by 5-10 times due to low mass loading of

  14. The energy of a moving quark-antiquark pair in an Script N = 4 SYM plasma

    Science.gov (United States)

    Chernicoff, Mariano; García, J. Antonio; Güijosa, Alberto

    2006-09-01

    We make use of the AdS/CFT correspondence to determine the energy of an external quark-antiquark pair that moves through strongly-coupled thermal Script N = 4 super-Yang-Mills plasma, both in the rest frame of the plasma and in the rest frame of the pair. It is found that the pair feels no drag force, has an energy that reproduces the expected 1/L (or γ/L) behavior at small quark-antiquark separations, and becomes unbound beyond a certain screening length whose velocity-dependence we determine. We discuss the relation between the high-velocity limit of our results and the lightlike Wilson loop proposed recently as a definition of the jet-quenching parameter.

  15. Plasma Photonic Devices for High Energy Density Science

    International Nuclear Information System (INIS)

    Kodama, R.

    2005-01-01

    High power laser technologies are opening a variety of attractive fields of science and technology using high energy density plasmas such as plasma physics, laboratory astrophysics, material science, nuclear science including medical applications and laser fusion. The critical issues in the applications are attributed to the control of intense light and enormous density of charged particles including efficient generation of the particles such as MeV electrons and protons with a current density of TA/cm2. Now these application possibilities are limited only by the laser technology. These applications have been limited in the control of the high power laser technologies and their optics. However, if we have another device consisted of the 4th material, i.e. plasma, we will obtain a higher energy density condition and explore the application possibilities, which could be called high energy plasma device. One of the most attractive devices has been demonstrated in the fast ignition scheme of the laser fusion, which is cone-guiding of ultra-intense laser light in to high density regions1. This is one of the applications of the plasma device to control the ultra-intense laser light. The other role of the devices consisted of transient plasmas is control of enormous energy-density particles in a fashion analogous to light control with a conventional optical device. A plasma fibre (5?m/1mm), as one example of the devices, has guided and deflected the high-density MeV electrons generated by ultra-intense laser light 2. The electrons have been well collimated with either a lens-like plasma device or a fibre-like plasma, resulting in isochoric heating and creation of ultra-high pressures such as Giga bar with an order of 100J. Plasmas would be uniquely a device to easily control the higher energy density particles like a conventional optical device as well as the ultra-intense laser light, which could be called plasma photonic device. (Author)

  16. Pair-breaking effects by parallel magnetic field in electric-field-induced surface superconductivity

    International Nuclear Information System (INIS)

    Nabeta, Masahiro; Tanaka, Kenta K.; Onari, Seiichiro; Ichioka, Masanori

    2016-01-01

    Highlights: • Zeeman effect shifts superconducting gaps of sub-band system, towards pair-breaking. • Higher-level sub-bands become normal-state-like electronic states by magnetic fields. • Magnetic field dependence of zero-energy DOS reflects multi-gap superconductivity. - Abstract: We study paramagnetic pair-breaking in electric-field-induced surface superconductivity, when magnetic field is applied parallel to the surface. The calculation is performed by Bogoliubov-de Gennes theory with s-wave pairing, including the screening effect of electric fields by the induced carriers near the surface. Due to the Zeeman shift by applied fields, electronic states at higher-level sub-bands become normal-state-like. Therefore, the magnetic field dependence of Fermi-energy density of states reflects the multi-gap structure in the surface superconductivity.

  17. Casimir energy density for spherical universes in n-dimensional spacetime

    International Nuclear Information System (INIS)

    Oezcan, Mustafa

    2006-01-01

    We consider the Casimir effect for the massless conformal scalar field in an n-dimensional, closed, static universe. We calculate the renormalized vacuum energy density using the covariant point-splitting method, the mode-sum regularization and the renormalized vacuum energy with the zeta-function regularization. We observe that all odd spacetime dimensions give us the zero renormalized vacuum energy density. For even spacetime dimensions the renormalized vacuum energy density oscillates in sign. The result agrees with three regularization techniques. The Casimir energy density for spherical universes in n-dimensional spacetime is regarded as interesting both to understand the correspondence between the sign of the effect and the dimension of manifold in topology and as a key to confirming the Casimir energy for half spherical universes (manifold with boundary) in n-dimensional spacetime

  18. Derivation of the density functional theory from the cluster expansion.

    Science.gov (United States)

    Hsu, J Y

    2003-09-26

    The density functional theory is derived from a cluster expansion by truncating the higher-order correlations in one and only one term in the kinetic energy. The formulation allows self-consistent calculation of the exchange correlation effect without imposing additional assumptions to generalize the local density approximation. The pair correlation is described as a two-body collision of bound-state electrons, and modifies the electron- electron interaction energy as well as the kinetic energy. The theory admits excited states, and has no self-interaction energy.

  19. Statistical properties of kinetic and total energy densities in reverberant spaces

    DEFF Research Database (Denmark)

    Jacobsen, Finn; Molares, Alfonso Rodriguez

    2010-01-01

    Many acoustical measurements, e.g., measurement of sound power and transmission loss, rely on determining the total sound energy in a reverberation room. The total energy is usually approximated by measuring the mean-square pressure (i.e., the potential energy density) at a number of discrete....... With the advent of a three-dimensional particle velocity transducer, it has become somewhat easier to measure total rather than only potential energy density in a sound field. This paper examines the ensemble statistics of kinetic and total sound energy densities in reverberant enclosures theoretically...... positions. The idea of measuring the total energy density instead of the potential energy density on the assumption that the former quantity varies less with position than the latter goes back to the 1930s. However, the phenomenon was not analyzed until the late 1970s and then only for the region of high...

  20. Probing the pairing interaction through two-neutron transfer reactions

    Directory of Open Access Journals (Sweden)

    Margueron J.

    2012-12-01

    Full Text Available The treatment of the pairing interaction in mean-field-based models is addressed. In particular, the possibility to use pair transfers as A tool to better constrain this interaction is discussed. First, pairing inter-actions with various density dependencies (surface/volume mixing are used in the microscopic Hartree-Fock-Bogoliubov + quasiparticle random-phase approximation model to generate the form factors to be used in reaction calculations. Cross sections for (p,t two-neutron transfer reactions are calculated in the one-step zero-range distorted-wave Born approximation for some Tin isotopes and for incident proton energies from 15 to 35 MeV. Three different surface/volume mixings of A zero-range density-dependent pairing interaction are employed in the microscopic calculations and the sensitivity of the cross sections to the different mixings is analyzed. Differences among the three different theoretical predictions are found espacially for the nucleus 136Sn and they are more important at the incident proton energy of 15 MeV. We thus indicate (p,t two-neutron transfer reactions with very neutron-rich Sn isotopes and at proton energies around 15 MeV as good experimental cases where the surface/volume mixing of the pairing interaction may be probed. In the second part of the manuscript, ground-state to ground-state transitions are investigated. Approximations made to estimate two-nucleon transfer probabilities in ground-state to ground-state transitions and the physical interpretation of these probabilities are discussed. Probabilities are often calculated by approximating both ground states of the initial nucleus A and of the final nucleus A±2 by the same quasiparticle vacuum. We analyze two improvements of this approach. First, the effect of using two different ground states with average numbers of particles A and A±2 is quantified. Second, by using projection techniques, the role of particle number restoration is analyzed. Our analysis

  1. Influence of ion pairing in ionic liquids on electrical double layer structures and surface force using classical density functional approach.

    Science.gov (United States)

    Ma, Ke; Forsman, Jan; Woodward, Clifford E

    2015-05-07

    We explore the influence of ion pairing in room temperature ionic liquids confined by planar electrode surfaces. Using a coarse-grained model for the aromatic ionic liquid [C4MIM(+)][BF4 (-)], we account for an ion pairing component as an equilibrium associating species within a classical density functional theory. We investigated the resulting structure of the electrical double layer as well as the ensuing surface forces and differential capacitance, as a function of the degree of ion association. We found that the short-range structure adjacent to surfaces was remarkably unaffected by the degree of ion pairing, up to several molecular diameters. This was even the case for 100% of ions being paired. The physical implications of ion pairing only become apparent in equilibrium properties that depend upon the long-range screening of charges, such as the asymptotic behaviour of surface forces and the differential capacitance, especially at low surface potential. The effect of ion pairing on capacitance is consistent with their invocation as a source of the anomalous temperature dependence of the latter. This work shows that ion pairing effects on equilibrium properties are subtle and may be difficult to extract directly from simulations.

  2. The topology of the Coulomb potential density. A comparison with the electron density, the virial energy density, and the Ehrenfest force density.

    Science.gov (United States)

    Ferreira, Lizé-Mari; Eaby, Alan; Dillen, Jan

    2017-12-15

    The topology of the Coulomb potential density has been studied within the context of the theory of Atoms in Molecules and has been compared with the topologies of the electron density, the virial energy density and the Ehrenfest force density. The Coulomb potential density is found to be mainly structurally homeomorphic with the electron density. The Coulomb potential density reproduces the non-nuclear attractor which is observed experimentally in the molecular graph of the electron density of a Mg dimer, thus, for the first time ever providing an alternative and energetic foundation for the existence of this critical point. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  3. The relation between food price, energy density and diet quality

    Directory of Open Access Journals (Sweden)

    Margareta Bolarić

    2013-01-01

    Full Text Available Low energy density diet, high in fruits and vegetables, is related to lower obesity risk and to better health status, but is more expensive. High energy density diet, high in added sugar and fats, is more affordable, but is related to higher obesity and chronic diseases risk. The aim of this study was to report prices according to energy density (low vs. high of food items and to show how food affordability could affect food choice and consumers’ health. Data was collected for 137 raw and processed foods from three purchase sites in Zagreb (one representative for supermarket, one smaller shop and green market. Results showed that low energy density food is more expensive than high energy density food (for example, the price of 1000 kcal from green zucchini (15 kcal/100 g is 124.20 kn while the price of 1000 kcal from sour cream (138 kcal/100 g is 13.99 kn. Food energy price was significantly different (p<0.05 between food groups with highest price for vegetable products (159.04 ± 36.18 kn/1000 kcal and raw vegetables (97.90 ± 50.13 kn/1000 kcal and lowest for fats (8.49 ± 1.22 kn/1000 kcal and cereals and products (5.66 ± 0.76 kn/1000 kcal. Negative correlation (Spearman r=-0.72, p<0.0001 was observed for energy density (kcal/100 g and price of 1000 kcal. Therefore, it is advisable to develop strategies in order to reduce price of low energy density food and encourage its intake since it would improve diet quality, which could lead to better costumers’ health.

  4. A Model of Electron-Positron Pair Formation

    Directory of Open Access Journals (Sweden)

    Lehnert B.

    2008-01-01

    Full Text Available The elementary electron-positron pair formation process is consideredin terms of a revised quantum electrodynamic theory, with specialattention to the conservation of energy, spin, and electric charge.The theory leads to a wave-packet photon model of narrow line widthand needle-radiation properties, not being available from conventionalquantum electrodynamics which is based on Maxwell's equations. Themodel appears to be consistent with the observed pair productionprocess, in which the created electron and positron form two raysthat start within a very small region and have original directionsalong the path of the incoming photon. Conservation of angular momentum requires the photon to possess a spin, as given by the present theory but not by the conventional one. The nonzero electric field divergence further gives rise to a local intrinsic electric charge density within the photon body, whereas there is a vanishing total charge of the latter. This may explain the observed fact that the photon decays on account of the impact from an external electric field. Such a behaviour should not become possible for a photon having zero local electric charge density.

  5. S-pairing in neutron matter: I. Correlated basis function theory

    International Nuclear Information System (INIS)

    Fabrocini, Adelchi; Fantoni, Stefano; Illarionov, Alexey Yu.; Schmidt, Kevin E.

    2008-01-01

    S-wave pairing in neutron matter is studied within an extension of correlated basis function (CBF) theory to include the strong, short range spatial correlations due to realistic nuclear forces and the pairing correlations of the Bardeen, Cooper and Schrieffer (BCS) approach. The correlation operator contains central as well as tensor components. The correlated BCS scheme of [S. Fantoni, Nucl. Phys. A 363 (1981) 381], developed for simple scalar correlations, is generalized to this more realistic case. The energy of the correlated pair condensed phase of neutron matter is evaluated at the two-body order of the cluster expansion, but considering the one-body density and the corresponding energy vertex corrections at the first order of the Power Series expansion. Based on these approximations, we have derived a system of Euler equations for the correlation factors and for the BCS amplitudes, resulting in correlated nonlinear gap equations, formally close to the standard BCS ones. These equations have been solved for the momentum independent part of several realistic potentials (Reid, Argonne v 14 and Argonne v 8 ' ) to stress the role of the tensor correlations and of the many-body effects. Simple Jastrow correlations and/or the lack of the density corrections enhance the gap with respect to uncorrelated BCS, whereas it is reduced according to the strength of the tensor interaction and following the inclusion of many-body contributions

  6. High Energy Density Polymer Film Capacitors

    National Research Council Canada - National Science Library

    Boufelfel, Ali

    2006-01-01

    High-energy-density capacitors that are compact and light-weight are extremely valuable in a number of critical DoD systems that include portable field equipment, pulsed lasers, detection equipment...

  7. The energy density distribution of an ideal gas and Bernoulli’s equations

    Science.gov (United States)

    Santos, Leonardo S. F.

    2018-05-01

    This work discusses the energy density distribution in an ideal gas and the consequences of Bernoulli’s equation and the corresponding relation for compressible fluids. The aim of this work is to study how Bernoulli’s equation determines the energy flow in a fluid, although Bernoulli’s equation does not describe the energy density itself. The model from molecular dynamic considerations that describes an ideal gas at rest with uniform density is modified to explore the gas in motion with non-uniform density and gravitational effects. The difference between the component of the speed of a particle that is parallel to the gas speed and the gas speed itself is called ‘parallel random speed’. The pressure from the ‘parallel random speed’ is denominated as parallel pressure. The modified model predicts that the energy density is the sum of kinetic and potential gravitational energy densities plus two terms with static and parallel pressures. The application of Bernoulli’s equation and the corresponding relation for compressible fluids in the energy density expression has resulted in two new formulations. For incompressible and compressible gas, the energy density expressions are written as a function of stagnation, static and parallel pressures, without any dependence on kinetic or gravitational potential energy densities. These expressions of the energy density are the main contributions of this work. When the parallel pressure was uniform, the energy density distribution for incompressible approximation and compressible gas did not converge to zero for the limit of null static pressure. This result is rather unusual because the temperature tends to zero for null pressure. When the gas was considered incompressible and the parallel pressure was equal to static pressure, the energy density maintained this unusual behaviour with small pressures. If the parallel pressure was equal to static pressure, the energy density converged to zero for the limit of the

  8. Diagnosing holographic type dark energy models with the Statefinder hierarchy, composite null diagnostic and w- w' pair

    Science.gov (United States)

    Zhao, Ze; Wang, Shuang

    2018-03-01

    The main purpose of this work is to distinguish various holographic type dark energy (DE) models, including the ΛHDE, HDE, NADE, and RDE model, by using various diagnostic tools. The first diagnostic tool is the Statefinder hierarchy, in which the evolution of Statefinder hierarchy parmeter S (1) 3( z) and S (1) 4( z) are studied. The second is composite null diagnostic (CND), in which the trajectories of { S (1) 3, ɛ} and { S (1) 4, ɛ} are investigated, where ɛ is the fractional growth parameter. The last is w-w' analysis, where w is the equation of state for DE and the prime denotes derivative with respect to ln a. In the analysis we consider two cases: varying current fractional DE density Ω de0 and varying DE model parameter C. We find that: (1) both the Statefinder hierarchy and the CND have qualitative impact on ΛHDE, but only have quantitative impact on HDE. (2) S (1) 4 can lead to larger differences than S (1) 3, while the CND pair has a stronger ability to distinguish different models than the Statefinder hierarchy. (3) For the case of varying C, the { w,w'} pair has qualitative impact on ΛHDE; for the case of varying Ω de0, the { w, w'} pair only has quantitative impact; these results are different from the cases of HDE, RDE, and NADE, in which the {w,w'} pair only has quantitative impact on these models. In conclusion, compared with HDE, RDE, and NADE, the ΛHDE model can be easily distinguished by using these diagnostic tools.

  9. New calculations and measurements of the Coulomb cross-section for the production of direct electron pairs by high energy nuclei

    Science.gov (United States)

    Derrickson, J. H.; Dake, S.; Dong, B. L.; Eby, P. B.; Fountain, W. F.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Iyono, A.; King, D. T.

    1989-01-01

    Recently, new calculations were made of the direct Coulomb pair cross section that rely less in arbitrary parameters. More accurate calculations of the cross section down to low pair energies were made. New measurements of the total direct electron pair yield, and the energy and angular distribution of the electron pairs in emulsion were made for O-16 at 60 and 200 GeV/amu at S-32 at 200 GeV/amu which give satisfactory agreement with the new calculations. These calculations and measurements are presented along with previous accelerator measurements made of this effect during the last 40 years. The microscope scanning criteria used to identify the direct electron pairs is described. Prospects for application of the pair method to cosmic ray energy measurements in the region 10 (exp 13) to 10 (exp 15) eV/amu are discussed.

  10. Remarks on saturation of energy confinement in high density regime on LHD

    International Nuclear Information System (INIS)

    Yamada, Hiroshi; Morita, Shigeru; Murakami, Sadayoshi

    2003-01-01

    A study on energy confinement times in currentless helical plasmas has indicated a preferable density dependence like τ E ∝ n-bar e 0.5-0.6 . However, saturation of energy confinement time has been often observed during the density ramping-up phase by gas puffing in NBI heated plasmas in LHD. The power balance analysis indicates that the thermal diffusivity is improved by the increase in local density while the global energy confinement time loses the dependence on the density. The flat or hollow density profile, which is distinguished in the density-ramping phase, promotes a broad heat power deposition. This change explains the apparent contradiction between the density dependence of the thermal diffusivity and the global energy confinement time. This result suggests that central heating can maintain a favorable density dependence of the energy confinement time in the high density regime. (author)

  11. High energy density capacitors fabricated by thin film technology

    International Nuclear Information System (INIS)

    Barbee, T W; Johnson, G W; Wagner, A V.

    1999-01-01

    Low energy density in conventional capacitors severely limits efforts to miniaturize power electronics and imposes design limitations on electronics in general. We have successfully applied physical vapor deposition technology to greatly increase capacitor energy density. The high dielectric breakdown strength we have achieved in alumina thin films allows high energy density to be achieved with this moderately low dielectric constant material. The small temperature dependence of the dielectric constant, and the high reliability, high resistivity, and low dielectric loss of Al 2 O 3 , make it even more appealing. We have constructed single dielectric layer thin film capacitors and shown that they can be stacked to form multilayered structures with no loss in yield for a given capacitance. Control of film growth morphology is critical for achieving the smooth, high quality interfaces between metal and dielectric necessary for device operation at high electric fields. Most importantly, high rate deposition with extremely low particle generation is essential for achieving high energy storage at a reasonable cost. This has been achieved by reactive magnetron sputtering in which the reaction to form the dielectric oxide has been confined to the deposition surface. By this technique we have achieved a yield of over 50% for 1 cm 2 devices with an energy density of 14 J per cubic centimeter of Al 2 O 3 dielectric material in 1.2 kV, 4 nF devices. By further reducing defect density and increasing the dielectric constant of the material, we will be able to increase capacitance and construct high energy density devices to meet the requirements of applications in power electronics

  12. Semi-local machine-learned kinetic energy density functional with third-order gradients of electron density

    Science.gov (United States)

    Seino, Junji; Kageyama, Ryo; Fujinami, Mikito; Ikabata, Yasuhiro; Nakai, Hiromi

    2018-06-01

    A semi-local kinetic energy density functional (KEDF) was constructed based on machine learning (ML). The present scheme adopts electron densities and their gradients up to third-order as the explanatory variables for ML and the Kohn-Sham (KS) kinetic energy density as the response variable in atoms and molecules. Numerical assessments of the present scheme were performed in atomic and molecular systems, including first- and second-period elements. The results of 37 conventional KEDFs with explicit formulae were also compared with those of the ML KEDF with an implicit formula. The inclusion of the higher order gradients reduces the deviation of the total kinetic energies from the KS calculations in a stepwise manner. Furthermore, our scheme with the third-order gradient resulted in the closest kinetic energies to the KS calculations out of the presented functionals.

  13. Baryonic 3P2-dominant superfluidity under combined pion condensation with Δ isobar. II). Properties of pairing interaction and numerical results

    International Nuclear Information System (INIS)

    Tamagaki, Ryozo

    2007-01-01

    According to the formulation developed in I, we calculate energy gaps of the baryonic 3 P 2 -dominant superfluidity under the combined pion condensation with Δ-mixing at moderately high density in neutron star interior. Adopting a baryon-baryon potential extended from a 'root' NN potential to be workable in the N+Δ space, we obtain the concrete form of the pairing interaction matrix elements between the quasi-baryon pairs, which constitute a two-dimensional angular-momentum stretched state and a charge triplet. With use of OPEG-B as a 'root' NN potential and an available set of the parameters representing the combined pion condensation, we study the properties of two-dimensional pairing potentials and the matrix elements of pairing interaction. We find that the strong attraction of pairing interaction for the quasi-neutron pairs is brought about by the spin-orbit potential and the spin- and isospin-dependent core terms of the central potential, whose effects are enhanced due to the pion condensation. The quasi-neutron pair plays a decisive role to bring about meaningful energy gaps, while the coupling between different quasi-baryon pairs plays no important role, as a consequence of a unique feature of the combined pion condensation we adopt. We numerically solve the energy gap equation for baryon density of (2-6) times the nuclear density and clarify substantial aspects of resulting superfluid energy gaps, and discuss related problems by taking into account possible change in the factors affecting the energy gaps, such as baryon-baryon potentials, some of the pion condensation parameters and an effective mass of the quasi-particle. Standing on these results, we can say that the 3 P 2 -dominant superfluid is realized with the critical temperatures T c of the order of 10 9 K, equivalent to the energy gaps of the order of 0.1 MeV, under the combined pion condensation in neutron star matter. The key point of the recognition lies in the aspects that the

  14. Baryonic 3 P2-Dominant Superfluidity under Combined Pion Condensation with Δ Isobar. II --- Properties of Pairing Interaction and Numerical Results ---

    Science.gov (United States)

    Tamagaki, R.; Takatsuka, T.

    2007-05-01

    According to the formulation developed in I, we calculate energy gaps of the baryonic (3) P_2-dominant superfluidity under the combined pion condensation with Delta-mixing at moderately high density in neutron star interior. Adopting a baryon-baryon potential extended from a ``root" NN potential to be workable in the N + Delta space, we obtain the concrete form of the pairing interaction matrix elements between the quasi-baryon pairs, which constitute a two-dimensional angular-momentum stretched state and a charge triplet. With use of OPEG-B as a ``root" NN potential and an available set of the parameters representing the combined pion condensation, we study the properties of two-dimensional pairing potentials and the matrix elements of pairing interaction. We find that the strong attraction of pairing interaction for the quasi-neutron pairs is brought about by the spin-orbit potential and the spin- and isospin-dependent core terms of the central potential, whose effects are enhanced due to the pion condensation. The quasi-neutron pair plays a decisive role to bring about meaningful energy gaps, while the coupling between different quasi-baryon pairs plays no important role, as a consequence of a unique feature of the combined pion condensation we adopt. We numerically solve the energy gap equation for baryon density of (2-6) times the nuclear density and clarify substantial aspects of resulting superfluid energy gaps, and discuss related problems by taking into account possible change in the factors affecting the energy gaps, such as baryon-baryon potentials, some of the pion condensation parameters and an effective mass of the quasi-particle. Standing on these results, we can say that the (3) P_2-dominant superfluid is realized with the critical temperatures T_c of the order of 10(9) K, equivalent to the energy gaps of the order of 0.1 MeV, under the combined pion condensation in neutron star matter. The key point of the recognition lies in the aspects that the

  15. Actinide chemistry using singlet-paired coupled cluster and its combinations with density functionals

    Science.gov (United States)

    Garza, Alejandro J.; Sousa Alencar, Ana G.; Scuseria, Gustavo E.

    2015-12-01

    Singlet-paired coupled cluster doubles (CCD0) is a simplification of CCD that relinquishes a fraction of dynamic correlation in order to be able to describe static correlation. Combinations of CCD0 with density functionals that recover specifically the dynamic correlation missing in the former have also been developed recently. Here, we assess the accuracy of CCD0 and CCD0+DFT (and variants of these using Brueckner orbitals) as compared to well-established quantum chemical methods for describing ground-state properties of singlet actinide molecules. The f0 actinyl series (UO22+, NpO23+, PuO24+), the isoelectronic NUN, and thorium (ThO, ThO2+) and nobelium (NoO, NoO2) oxides are studied.

  16. Density Functional Methods for Shock Physics and High Energy Density Science

    Science.gov (United States)

    Desjarlais, Michael

    2017-06-01

    Molecular dynamics with density functional theory has emerged over the last two decades as a powerful and accurate framework for calculating thermodynamic and transport properties with broad application to dynamic compression, high energy density science, and warm dense matter. These calculations have been extensively validated against shock and ramp wave experiments, are a principal component of high-fidelity equation of state generation, and are having wide-ranging impacts on inertial confinement fusion, planetary science, and shock physics research. In addition to thermodynamic properties, phase boundaries, and the equation of state, one also has access to electrical conductivity, thermal conductivity, and lower energy optical properties. Importantly, all these properties are obtained within the same theoretical framework and are manifestly consistent. In this talk I will give a brief history and overview of molecular dynamics with density functional theory and its use in calculating a wide variety of thermodynamic and transport properties for materials ranging from ambient to extreme conditions and with comparisons to experimental data. I will also discuss some of the limitations and difficulties, as well as active research areas. Sandia is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  17. Pairing fluctuations in trapped Fermi gases

    International Nuclear Information System (INIS)

    Viverit, Luciano; Bruun, Georg M.; Minguzzi, Anna; Fazio, Rosario

    2004-01-01

    We examine the contribution of pairing fluctuations to the superfluid order parameter for harmonically trapped atomic Fermi gases in the BCS regime. In the limit of small systems we consider, both analytically and numerically, their space and temperature dependence. We predict a parity effect, i.e., that pairing fluctuations show a maximum or a minimum at the center of the trap, depending on the value of the last occupied shell being even or odd. We propose to detect pairing fluctuations by measuring the density-density correlation function after a ballistic expansion of the gas

  18. Fifth International Conference on High Energy Density Physics

    Energy Technology Data Exchange (ETDEWEB)

    Beg, Farhat

    2017-07-05

    The Fifth International Conference on High Energy Density Physics (ICHED 2015) was held in the Catamaran Hotel in San Diego from August 23-27, 2015. This meeting was the fifth in a series which began in 2008 in conjunction with the April meeting of the American Physical Society (APS). The main goal of this conference has been to bring together researchers from all fields of High Energy Density Science (HEDS) into one, unified meeting.

  19. 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

  20. Molecular solar thermal energy storage in photoswitch oligomers increases energy densities and storage times.

    Science.gov (United States)

    Mansø, Mads; Petersen, Anne Ugleholdt; Wang, Zhihang; Erhart, Paul; Nielsen, Mogens Brøndsted; Moth-Poulsen, Kasper

    2018-05-16

    Molecular photoswitches can be used for solar thermal energy storage by photoisomerization into high-energy, meta-stable isomers; we present a molecular design strategy leading to photoswitches with high energy densities and long storage times. High measured energy densities of up to 559 kJ kg -1 (155 Wh kg -1 ), long storage lifetimes up to 48.5 days, and high quantum yields of conversion of up to 94% per subunit are demonstrated in norbornadiene/quadricyclane (NBD/QC) photo-/thermoswitch couples incorporated into dimeric and trimeric structures. By changing the linker unit between the NBD units, we can at the same time fine-tune light-harvesting and energy densities of the dimers and trimers so that they exceed those of their monomeric analogs. These new oligomers thereby meet several of the criteria to be met for an optimum molecule to ultimately enter actual devices being able to undergo closed cycles of solar light-harvesting, energy storage, and heat release.

  1. Polarization effects for pair creation by photon in oriented crystals at high energy

    International Nuclear Information System (INIS)

    Baier, V.N.; Katkov, V.M.

    2006-01-01

    Pair creation by a photon in an oriented crystal is considered in the frame of the quasiclassical operator method, which includes processes with polarized particles. Under some quite generic assumptions the general expression is derived for the probability of pair creation of longitudinally polarized electron (positron) by circularly polarized photon in oriented crystal. In the particular cases θ > V /m (θ is the angle of incidence, angle between the momentum of the initial photon and axis (plane) of crystal, V is the scale of a potential of axis or a plane relative to which the angle θ is defined) one has the constant field approximation and the coherent pair production theory correspondingly. Side by side with coherent process the probability of incoherent pair creation is calculated, which differs essentially from amorphous one. At high energy the pair creation in oriented crystal is strongly enhanced comparing with the amorphous medium. In the corresponding appendixes the integral polarization of positron is found in an external field and for the coherent and incoherent mechanisms

  2. Airfoil-based electromagnetic energy harvester containing parallel array motion between moving coil and multi-pole magnets towards enhanced power density.

    Science.gov (United States)

    Leung, Chung Ming; Wang, Ya; Chen, Wusi

    2016-11-01

    In this letter, the airfoil-based electromagnetic energy harvester containing parallel array motion between moving coil and trajectory matching multi-pole magnets was investigated. The magnets were aligned in an alternatively magnetized formation of 6 magnets to explore enhanced power density. In particular, the magnet array was positioned in parallel to the trajectory of the tip coil within its tip deflection span. The finite element simulations of the magnetic flux density and induced voltages at an open circuit condition were studied to find the maximum number of alternatively magnetized magnets that was required for the proposed energy harvester. Experimental results showed that the energy harvester with a pair of 6 alternatively magnetized linear magnet arrays was able to generate an induced voltage (V o ) of 20 V, with an open circuit condition, and 475 mW, under a 30 Ω optimal resistance load operating with the wind speed (U) at 7 m/s and a natural bending frequency of 3.54 Hz. Compared to the traditional electromagnetic energy harvester with a single magnet moving through a coil, the proposed energy harvester, containing multi-pole magnets and parallel array motion, enables the moving coil to accumulate a stronger magnetic flux in each period of the swinging motion. In addition to the comparison made with the airfoil-based piezoelectric energy harvester of the same size, our proposed electromagnetic energy harvester generates 11 times more power output, which is more suitable for high-power-density energy harvesting applications at regions with low environmental frequency.

  3. Cumulative approaches to track formation under swift heavy ion (SHI) irradiation: Phenomenological correlation with formation energies of Frenkel pairs

    Energy Technology Data Exchange (ETDEWEB)

    Crespillo, M.L., E-mail: mcrespil@utk.edu [Centro de Microanálisis de Materiales, CMAM-UAM, Cantoblanco, Madrid 28049 (Spain); Department of Materials Science & Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Agulló-López, F., E-mail: fal@uam.es [Centro de Microanálisis de Materiales, CMAM-UAM, Cantoblanco, Madrid 28049 (Spain); Zucchiatti, A. [Centro de Microanálisis de Materiales, CMAM-UAM, Cantoblanco, Madrid 28049 (Spain)

    2017-03-01

    Highlights: • Extensive survey formation energies Frenkel pairs and electronic stopping thresholds. • Correlation: track formation thresholds and the energies for Frenkel pair formation. • Formation energies Frenkel pairs discussed in relation to the cumulative mechanisms. • Amorphous track formation mechanisms: defect accumulation models versus melting. • Advantages cumulative models to deal with new hot topics: nuclear-electronic synergy. - Abstract: An extensive survey for the formation energies of Frenkel pairs, as representative candidates for radiation-induced point defects, is presented and discussed in relation to the cumulative mechanisms (CM) of track formation in dielectric materials under swift heavy ion (SHI) irradiation. These mechanisms rely on the generation and accumulation of point defects during irradiation followed by collapse of the lattice once a threshold defect concentration is reached. The physical basis of those approaches has been discussed by Fecht as a defect-assisted transition to an amorphous phase. Although a first quantitative analysis of the CM model was previously performed for LiNbO{sub 3} crystals, we have, here, adopted a broader phenomenological approach. It explores the correlation between track formation thresholds and the energies for Frenkel pair formation for a broad range of materials. It is concluded that the threshold stopping powers can be roughly scaled with the energies required to generate a critical Frenkel pair concentration in the order of a few percent of the total atomic content. Finally, a comparison with the predictions of the thermal spike model is discussed within the analytical Szenes approximation.

  4. Non-empirical energy density functional for the nuclear structure

    International Nuclear Information System (INIS)

    Rot ival, V.

    2008-09-01

    The energy density functional (EDF) formalism is the tool of choice for large-scale low-energy nuclear structure calculations both for stable experimentally known nuclei whose properties are accurately reproduced and systems that are only theoretically predicted. We highlight in the present dissertation the capability of EDF methods to tackle exotic phenomena appearing at the very limits of stability, that is the formation of nuclear halos. We devise a new quantitative and model-independent method that characterizes the existence and properties of halos in medium- to heavy-mass nuclei, and quantifies the impact of pairing correlations and the choice of the energy functional on the formation of such systems. These results are found to be limited by the predictive power of currently-used EDFs that rely on fitting to known experimental data. In the second part of this dissertation, we initiate the construction of non-empirical EDFs that make use of the new paradigm for vacuum nucleon-nucleon interactions set by so-called low-momentum interactions generated through the application of renormalization group techniques. These soft-core vacuum potentials are used as a step-stone of a long-term strategy which connects modern many-body techniques and EDF methods. We provide guidelines for designing several non-empirical models that include in-medium many-body effects at various levels of approximation, and can be handled in state-of-the art nuclear structure codes. In the present work, the first step is initiated through the adjustment of an operator representation of low-momentum vacuum interactions using a custom-designed parallel evolutionary algorithm. The first results highlight the possibility to grasp most of the relevant physics for low-energy nuclear structure using this numerically convenient Gaussian vertex. (author)

  5. Cosmic-ray energy densities in star-forming galaxies

    Directory of Open Access Journals (Sweden)

    Persic Massimo

    2017-01-01

    Full Text Available The energy density of cosmic ray protons in star forming galaxies can be estimated from π0-decay γ-ray emission, synchrotron radio emission, and supernova rates. To galaxies for which these methods can be applied, the three methods yield consistent energy densities ranging from Up ~ 0.1 − 1 eV cm−3 to Up ~ 102 − 103 eV cm−3 in galaxies with low to high star-formation rates, respectively.

  6. Longitudinal density modulation and energy conversion in intense beams

    International Nuclear Information System (INIS)

    Harris, J. R.; Neumann, J. G.; Tian, K.; O'Shea, P. G.

    2007-01-01

    Density modulation of charged particle beams may occur as a consequence of deliberate action, or may occur inadvertently because of imperfections in the particle source or acceleration method. In the case of intense beams, where space charge and external focusing govern the beam dynamics, density modulation may, under some circumstances, be converted to velocity modulation, with a corresponding conversion of potential energy to kinetic energy. Whether this will occur depends on the properties of the beam and the initial modulation. This paper describes the evolution of discrete and continuous density modulations on intense beams and discusses three recent experiments related to the dynamics of density-modulated electron beams

  7. Anti-Ferroelectric Ceramics for High Energy Density Capacitors

    Directory of Open Access Journals (Sweden)

    Aditya Chauhan

    2015-11-01

    Full Text Available With an ever increasing dependence on electrical energy for powering modern equipment and electronics, research is focused on the development of efficient methods for the generation, storage and distribution of electrical power. In this regard, the development of suitable dielectric based solid-state capacitors will play a key role in revolutionizing modern day electronic and electrical devices. Among the popular dielectric materials, anti-ferroelectrics (AFE display evidence of being a strong contender for future ceramic capacitors. AFE materials possess low dielectric loss, low coercive field, low remnant polarization, high energy density, high material efficiency, and fast discharge rates; all of these characteristics makes AFE materials a lucrative research direction. However, despite the evident advantages, there have only been limited attempts to develop this area. This article attempts to provide a focus to this area by presenting a timely review on the topic, on the relevant scientific advancements that have been made with respect to utilization and development of anti-ferroelectric materials for electric energy storage applications. The article begins with a general introduction discussing the need for high energy density capacitors, the present solutions being used to address this problem, and a brief discussion of various advantages of anti-ferroelectric materials for high energy storage applications. This is followed by a general description of anti-ferroelectricity and important anti-ferroelectric materials. The remainder of the paper is divided into two subsections, the first of which presents various physical routes for enhancing the energy storage density while the latter section describes chemical routes for enhanced storage density. This is followed by conclusions and future prospects and challenges which need to be addressed in this particular field.

  8. Novel nanostructured materials for high energy density supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, C.Z.; Zhang, X.G. [Nanjing Univ. of Aeronautics and Astronautics (China). College of Material Science and Engineering

    2010-07-01

    Researchers are currently examining methods of improving energy density while not sacrificing the high power density of supercapacitors. In this study, nanostructured materials assembled from nanometer-sized building blocks with mesoporosity were synthesized in order investigate diffusion time, kinetics, and capacitances. Petal-like cobalt hydroxide Co(OH){sub 2} mesocrystals, urchin-like Co(OH){sub 2} and dicobalt tetroxide (Co{sub 2}O{sub 4}) ordered arrays as well as N{sub i}O microspheres were assembled from 0-D nanoparticles, 1-D mesoporous nanowires and nanobelts, and 2-D mesoporous nanopetals. The study showed that all the synthesized nanostructured materials delivered larger energy densities while showing electrochemical stability at high rates.

  9. An exposition on Friedmann cosmology with negative energy densities

    International Nuclear Information System (INIS)

    Nemiroff, Robert J.; Joshi, Ravi; Patla, Bijunath R.

    2015-01-01

    How would negative energy density affect a classic Friedmann cosmology? Although never measured and possibly unphysical, certain realizations of quantum field theories leaves the door open for such a possibility. In this paper we analyze the evolution of a universe comprising varying amounts of negative energy forms. Negative energy components have negative normalized energy densities, Ω < 0. They include negative phantom energy with an equation of state parameter w < −1, negative cosmological constant: w=−1, negative domain walls: w = −2/3, negative cosmic strings: w=−1/3, negative mass: w = 0, negative radiation: w = 1/3 and negative ultralight: w > 1/3. Assuming that such energy forms generate pressure like perfect fluids, the attractive or repulsive nature of negative energy components are reviewed. The Friedmann equation is satisfied only when negative energy forms are coupled to a greater magnitude of positive energy forms or positive curvature. We show that the solutions exhibit cyclic evolution with bounces and turnovers.The future and fate of such universes in terms of curvature, temperature, acceleration, and energy density are reviewed. The end states are dubbed ''big crunch,' '' big void,' or ''big rip' and further qualified as ''warped',''curved', or ''flat',''hot' versus ''cold', ''accelerating' versus ''decelerating' versus ''coasting'. A universe that ends by contracting to zero energy density is termed ''big poof.' Which contracting universes ''bounce' in expansion and which expanding universes ''turnover' into contraction are also reviewed

  10. Energy density of lake whitefish Coregonus clupeaformis in Lakes Huron and Michigan

    Science.gov (United States)

    Pothoven, S.A.; Nalepa, T.F.; Madenjian, C.P.; Rediske, R.R.; Schneeberger, P.J.; He, J.X.

    2006-01-01

    We collected lake whitefish Coregonus clupeaformis off Alpena and Tawas City, Michigan, USA in Lake Huron and off Muskegon, Michigan USA in Lake Michigan during 2002–2004. We determined energy density and percent dry weight for lake whitefish from both lakes and lipid content for Lake Michigan fish. Energy density increased with increasing fish weight up to 800 g, and then remained relatively constant with further increases in fish weight. Energy density, adjusted for weight, was lower in Lake Huron than in Lake Michigan for both small (≤800 g) and large fish (>800 g). Energy density did not differ seasonally for small or large lake whitefish or between adult male and female fish. Energy density was strongly correlated with percent dry weight and percent lipid content. Based on data from commercially caught lake whitefish, body condition was lower in Lake Huron than Lake Michigan during 1981–2003, indicating that the dissimilarity in body condition between the lakes could be long standing. Energy density and lipid content in 2002–2004 in Lake Michigan were lower than data for comparable sized fish collected in 1969–1971. Differences in energy density between lakes were attributed to variation in diet and prey energy content as well as factors that affect feeding rates such as lake whitefish density and prey abundance.

  11. Probing the nuclear symmetry energy at high densities with nuclear reactions

    Science.gov (United States)

    Leifels, Y.

    2017-11-01

    The nuclear equation of state is a topic of highest current interest in nuclear structure and reactions as well as in astrophysics. The symmetry energy is the part of the equation of state which is connected to the asymmetry in the neutron/proton content. During recent years a multitude of experimental and theoretical efforts on different fields have been undertaken to constraint its density dependence at low densities but also above saturation density (ρ_0=0.16 fm ^{-3} . Conventionally the symmetry energy is described by its magnitude S_v and the slope parameter L , both at saturation density. Values of L = 44 -66MeV and S_v=31 -33MeV have been deduced in recent compilations of nuclear structure, heavy-ion reaction and astrophysics data. Apart from astrophysical data on mass and radii of neutron stars, heavy-ion reactions at incident energies of several 100MeV are the only means do access the high density behaviour of the symmetry energy. In particular, meson production and collective flows upto about 1 AGeV are predicted to be sensitive to the slope of the symmetry energy as a function of density. From the measurement of elliptic flow of neutrons with respect to charged particles at GSI, a more stringent constraint for the slope of the symmetry energy at supra-saturation densities has been deduced. Future options to reach even higher densities will be discussed.

  12. A Dual-Stimuli-Responsive Sodium-Bromine Battery with Ultrahigh Energy Density.

    Science.gov (United States)

    Wang, Faxing; Yang, Hongliu; Zhang, Jian; Zhang, Panpan; Wang, Gang; Zhuang, Xiaodong; Cuniberti, Gianaurelio; Feng, Xinliang

    2018-06-01

    Stimuli-responsive energy storage devices have emerged for the fast-growing popularity of intelligent electronics. However, all previously reported stimuli-responsive energy storage devices have rather low energy densities (energy density, electrochromic effect, and fast thermal response is demonstrated. Remarkably, the fabricated Na//Br 2 battery exhibits a large operating voltage of 3.3 V and an energy density up to 760 Wh kg -1 , which outperforms those for the state-of-the-art stimuli-responsive electrochemical energy storage devices. This work offers a promising approach for designing multi-stimuli-responsive and high-energy rechargeable batteries without sacrificing the electrochemical performance. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Dislocation processes in quasicrystals-Kink-pair formation control or jog-pair formation control

    International Nuclear Information System (INIS)

    Takeuchi, Shin

    2005-01-01

    A computer simulation of dislocation in a model quasiperiodic lattice indicates that the dislocation feels a large Peierls potential when oriented in particular directions. For a dislocation with a high Peierls potential, the glide velocity and the climb velocity of the dislocation can be described almost in parallel in terms of the kink-pair formation followed by kink motion and the jog-pair formation followed by jog motion, respectively. The activation enthalpy of the kink-pair formation is the sum of the kink-pair formation enthalpy and the atomic jump activation enthalpy, while the activation enthalpy of the jog-pair formation involves the jog-pair enthalpy and the self-diffusion enthalpy. Since the kink-pair energy can be considerably larger than the jog-pair energy, the climb velocity can be faster than the glide velocity, so that the plastic deformation of quasicrystals can be brought not by dislocation glide but by dislocation climb at high temperatures

  14. Formation energies of local pairs in fullerene isomer mixtures

    International Nuclear Information System (INIS)

    Solecki, J.

    1996-01-01

    It is well-known that the alkali metal-doped fullerides are superconductors of type II. There were so far many trials to explain the pairing mechanism in the superconducting fullerides. A description of the superconducting mechanism in terms of the so-called local pair model has been proposed in this note. A purely electronic interaction was also considered within the resonating valence bond model (RVB). In fact, other models were not able to explain exactly why superconductivity appears for the stoichiometry of A 3 C 60 in the alkali metal-doped fullerides. An exception of this rule is, e.g., Ca 5 C 60 which is a superconductor with T c = 8.4 K. However, measurements show that electronic structures near the Fermi level of the A 3 C 60 (A = K, Rb) as well as the Ca 5 C 60 superconductors are remarkably similar although their charge carriers form energy bands of different character. Therefore, the results obtained for the stoichiometry A 3 C 60 can roughly refer to the Ca 5 C 60 case as well. (orig.)

  15. High energy density, long life energy storage capacitor dielectric system

    International Nuclear Information System (INIS)

    Nichols, D.H.; Wilson, S.R.

    1977-01-01

    The evolution of energy storage dielectric systems shows a dramatic improvement in life and joule density, culminating in a 50% to 300% life improvement of polypropylene film-paper-phthalate ester over paper-castor oil depending on service. The physical and electrical drawbacks of castor oil are not present in the new system, allowing the capacitor designer to utilize the superior insulation resistance, dielectric strength, and corona resistance to full advantage. The result is longer life for equal joule density or greater joule density for equal life. Field service proof of the film-Geconol system superiority is based on 5 megajoule in operation and 16 megajoule on order

  16. A Low-Cost Neutral Zinc-Iron Flow Battery with High Energy Density for Stationary Energy Storage.

    Science.gov (United States)

    Xie, Congxin; Duan, Yinqi; Xu, Wenbin; Zhang, Huamin; Li, Xianfeng

    2017-11-20

    Flow batteries (FBs) are one of the most promising stationary energy-storage devices for storing renewable energy. However, commercial progress of FBs is limited by their high cost and low energy density. A neutral zinc-iron FB with very low cost and high energy density is presented. By using highly soluble FeCl 2 /ZnBr 2 species, a charge energy density of 56.30 Wh L -1 can be achieved. DFT calculations demonstrated that glycine can combine with iron to suppress hydrolysis and crossover of Fe 3+ /Fe 2+ . The results indicated that an energy efficiency of 86.66 % can be obtained at 40 mA cm -2 and the battery can run stably for more than 100 cycles. Furthermore, a low-cost porous membrane was employed to lower the capital cost to less than $ 50 per kWh, which was the lowest value that has ever been reported. Combining the features of low cost, high energy density and high energy efficiency, the neutral zinc-iron FB is a promising candidate for stationary energy-storage applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Cooper pairs' magnetic moment in MCFL color superconductivity

    International Nuclear Information System (INIS)

    Feng Bo; Ferrer, Efrain J.; Incera, Vivian de la

    2011-01-01

    We investigate the effect of the alignment of the magnetic moments of Cooper pairs of charged quarks that form at high density in three-flavor quark matter. The high-density phase of this matter in the presence of a magnetic field is known to be the Magnetic Color-Flavor-Locked (MCFL) phase of color superconductivity. We derive the Fierz identities of the theory and show how the explicit breaking of the rotational symmetry by the uniform magnetic field opens new channels of interactions and allows the formation of a new diquark condensate. The new order parameter is a spin-1 condensate proportional to the component in the field direction of the average magnetic moment of the pairs of charged quarks. The magnitude of the spin-1 condensate becomes comparable to the larger of the two scalar gaps in the region of large fields. The existence of the spin-1 condensate is unavoidable, as in the presence of a magnetic field there is no solution of the gap equations with nonzero scalar gaps and zero magnetic moment condensate. This is consistent with the fact that the extra condensate does not break any symmetry that has not already been broken by the known MCFL gaps. The spin-1 condensate enhances the condensation energy of pairs formed by charged quarks and the magnetization of the system. We discuss the possible consequences of the new order parameter on the issue of the chromomagnetic instability that appears in color superconductivity at moderate density.

  18. Clustering and Symmetry Energy in a Low Density Nuclear Gas

    International Nuclear Information System (INIS)

    Kowalski, S.; Natowitz, J.B.; Shlomo, S.; Wada, R.; Hagel, K.; Wang, J.; Materna, T.; Chen, Z.; Ma, Y.G.; Qin, L.; Botvina, A.S.; Fabris, D.; Lunardon, M.; Moretto, S.; Nebbia, G.; Pesente, S.; Rizzi, V.; Viesti, G.; Cinausero, M.; Prete, G.; Keutgen, T.; El Masri, Y.; Majka, Z.; Ono, A.

    2007-01-01

    Temperature and density dependent symmetry energy coefficients have been derived from isoscaling analyses of the yields of nuclei with A= 64 Zn projectiles with 92 Mo and 197 Au target nuclei. The symmetry energies at low density are larger than those obtained in mean field calculations, reflecting the clustering of low density nuclear matter. They are in quite good agreement with results of a recently proposed Virial Equation of State calculation

  19. Local density approximations for relativistic exchange energies

    International Nuclear Information System (INIS)

    MacDonald, A.H.

    1986-01-01

    The use of local density approximations to approximate exchange interactions in relativistic electron systems is reviewed. Particular attention is paid to the physical content of these exchange energies by discussing results for the uniform relativistic electron gas from a new point of view. Work on applying these local density approximations in atoms and solids is reviewed and it is concluded that good accuracy is usually possible provided self-interaction corrections are applied. The local density approximations necessary for spin-polarized relativistic systems are discussed and some new results are presented

  20. State-of-the-art ab initio potential energy curve for the krypton atom pair and thermophysical properties of dilute krypton gas.

    Science.gov (United States)

    Jäger, Benjamin; Hellmann, Robert; Bich, Eckard; Vogel, Eckhard

    2016-03-21

    A new reference krypton-krypton interatomic potential energy curve was developed by means of quantum-chemical ab initio calculations for 36 interatomic separations. Highly accurate values for the interaction energies at the complete basis set limit were obtained using the coupled-cluster method with single, double, and perturbative triple excitations as well as t-aug-cc-pV5Z and t-aug-cc-pV6Z basis sets including mid-bond functions, with the 6Z basis set being newly constructed for this study. Higher orders of coupled-cluster terms were considered in a successive scheme up to full quadruple excitations. Core-core and core-valence correlation effects were included. Furthermore, relativistic effects were studied not only at a scalar relativistic level using second-order direct perturbation theory, but also utilizing full four-component and Gaunt-effect computations. An analytical pair potential function was fitted to the interaction energies, which is characterized by a depth of 200.88 K with an estimated standard uncertainty of 0.51 K. Thermophysical properties of low-density krypton were calculated for temperatures up to 5000 K. Second and third virial coefficients were obtained from statistical thermodynamics. Viscosity and thermal conductivity as well as the self-diffusion coefficient were computed using the kinetic theory of gases. The theoretical results are compared with experimental data and with results for other pair potential functions from the literature, especially with those calculated from the recently developed ab initio potential of Waldrop et al. [J. Chem. Phys. 142, 204307 (2015)]. Highly accurate experimental viscosity data indicate that both the present ab initio pair potential and the one of Waldrop et al. can be regarded as reference potentials, even though the quantum-chemical methods and basis sets differ. However, the uncertainties of the present potential and of the derived properties are estimated to be considerably lower.

  1. ΛΛ pairing in NΛ composite matter

    International Nuclear Information System (INIS)

    Tanigawa, Tomonori; Matsuzaki, Masayuki; Chiba, Satoshi

    2003-01-01

    ΛΛ pairing correlation in binary mixed matter of nucleons and lambdas is studied within the relativistic Hartree-Bogoliubov model. Λ hyperons to be paired up are immersed in background nucleons in normal state. A phenomenological ΛΛ interaction, which is derived relativistically from the Lagrangian of the system, is adopted to the gap equation. It is found that increasing the nucleon density makes the ΛΛ pairing gap suppressed. This result suggests a mechanism, specific to relativistic models, of its dependence on the nucleon density. (author)

  2. ΛΛ pairing in NΛ composite matter

    International Nuclear Information System (INIS)

    Tanigawa, Tomonori; Matsuzaki, Masayuki; Chiba, Satoshi

    2002-01-01

    ΛΛ pairing correlation in binary mixed matter of nucleons and lambdas is studied within the relativistic Hartree-Bogoliubov model. Λ hyperons to be paired up are immersed in background nucleons in normal state. A phenomenological ΛΛ interaction, which is derived relativistically from the Lagrangian of the system, is adopted to the gap equation. It is found that increasing the nucleon density makes the ΛΛ pairing gap suppressed. This result suggests a mechanism, specific to relativistic models, of its dependence on the nucleon density. (author)

  3. Energy Density and Weight Loss: Feel Full on Fewer Calories

    Science.gov (United States)

    ... Behavior. 2009;97:609. Rouhani MH, et al. Associations between dietary energy density and obesity: A systematic review and meta-analysis of observational studies. Nutrition. 2016;32:1037. Stelmach-Mardas M, et al. Link between food energy density and body weight changes in obese ...

  4. Detecting W/Z pairs and Higgs at high energy pp colliders: Main experimental issues

    International Nuclear Information System (INIS)

    Alverson, G.; Bengtsson, H.U.; Hauptman, J.

    1987-03-01

    The main detection issues implied by the search for W and Z 0 pairs and Higgs in a high energy pp collider context are discussed here. It includes: precise electron identification, missing energy measurement, multilepton recognition, sophisticated jet pattern recognition, and pile-up. The study uses, as much as possible, a ''realistic simulation of life.''

  5. Dependence of two-neutron momentum densities on total pair momentum

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Joseph A [Los Alamos National Laboratory; Wiringa, R B [ANL; Schiavilla, R [JEFFERSON LAB; Pieper, Steven C [ANL

    2008-01-01

    Two-nucleon momentum distributions are calculated for the ground states of {sup 3}He and {sup 4}He as a function of the nucleons' relative and total momenta. We use variational Monte Carlo wave functions derived from a realistic Hamiltonian with two- and three-nucleon potentials. The momentum distribution of pp pairs is found to be much smaller than that of pn pairs for values of the relative momentum in the range (300--500) MeV/c and vanishing total momentum. Howeer, as the totalmomentum increases to 400 MeV/c, the ratio of pp to pn pairs in this relative momentum range grows and approaches the limit 1/2 for {sup 3}He and 1/4 for {sup 4}He, corresponding to the ratio of pp to pn pairs in these nuclei. This behavior should be easily observable in two-nucleon knock-out processes, such as A(e, e'pN).

  6. Neutron and proton densities and the symmetry energy

    International Nuclear Information System (INIS)

    Bodmer, A.R.; Usmani, Q.N.

    2003-01-01

    The neutron/proton distributions in nuclei, in particular, the n-p difference, are considered in a 'macroscopic' Thomas-Fermi approach. The density dependence F(ρ) of the symmetry-energy density, where ρ is the total density, drives this difference in the absence of Coulomb and density-gradient contributions when we obtain an explicit solution for the difference in terms of F. If F is constant then the n-p difference and, in particular, the difference δR between the neutron and proton rms radii are zero. The Coulomb energy and gradient terms are treated variationally. The latter make only a small contribution to the n-p difference, and this is then effectively determined by F. The Coulomb energy reduces δR. Switching off the Coulomb contribution to the n-p difference then gives the maximum δR for a given F. Our numerical results are for 208 Pb. We consider a wide range of F; for these, both δR and the ratio χ of the surface to volume symmetry-energy coefficient depend, approximately, only on an integral involving F -1 . For δR < or approx. 0.45 fm this dependence is one valued and approximately linear for small δR, and this integral is then effectively determined by δR. There is a strong correlation between δR and χ, allowing an approximate determination of χ from δR. δR has a maximum of congruent with 0.65 fm

  7. The electron localization as the information content of the conditional pair density

    Energy Technology Data Exchange (ETDEWEB)

    Urbina, Andres S.; Torres, F. Javier [Universidad San Francisco de Quito (USFQ), Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Química e Ingeniería Química, Diego de Robles y Via Interoceanica, Quito 17-1200-841 (Ecuador); Universidad San Francisco de Quito (USFQ), Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Via Interoceanica, Quito 17-1200-841 (Ecuador); Rincon, Luis, E-mail: lrincon@usfq.edu.ec, E-mail: lrincon@ula.ve [Universidad San Francisco de Quito (USFQ), Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Química e Ingeniería Química, Diego de Robles y Via Interoceanica, Quito 17-1200-841 (Ecuador); Universidad San Francisco de Quito (USFQ), Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Via Interoceanica, Quito 17-1200-841 (Ecuador); Departamento de Química, Facultad de Ciencias, Universidad de Los Andes (ULA), La Hechicera, Mérida-5101 (Venezuela, Bolivarian Republic of)

    2016-06-28

    In the present work, the information gained by an electron for “knowing” about the position of another electron with the same spin is calculated using the Kullback-Leibler divergence (D{sub KL}) between the same-spin conditional pair probability density and the marginal probability. D{sub KL} is proposed as an electron localization measurement, based on the observation that regions of the space with high information gain can be associated with strong correlated localized electrons. Taking into consideration the scaling of D{sub KL} with the number of σ-spin electrons of a system (N{sup σ}), the quantity χ = (N{sup σ} − 1) D{sub KL}f{sub cut} is introduced as a general descriptor that allows the quantification of the electron localization in the space. f{sub cut} is defined such that it goes smoothly to zero for negligible densities. χ is computed for a selection of atomic and molecular systems in order to test its capability to determine the region in space where electrons are localized. As a general conclusion, χ is able to explain the electron structure of molecules on the basis of chemical grounds with a high degree of success and to produce a clear differentiation of the localization of electrons that can be traced to the fluctuation in the average number of electrons in these regions.

  8. Nuclear energy density functional from chiral pion-nucleon dynamics revisited

    OpenAIRE

    Kaiser, N.; Weise, W.

    2009-01-01

    We use a recently improved density-matrix expansion to calculate the nuclear energy density functional in the framework of in-medium chiral perturbation theory. Our calculation treats systematically the effects from $1\\pi$-exchange, iterated $1\\pi$-exchange, and irreducible $2\\pi$-exchange with intermediate $\\Delta$-isobar excitations, including Pauli-blocking corrections up to three-loop order. We find that the effective nucleon mass $M^*(\\rho)$ entering the energy density functional is iden...

  9. Inflation of the screening length induced by Bjerrum pairs.

    Science.gov (United States)

    Zwanikken, Jos; van Roij, René

    2009-10-21

    Within a modified Poisson-Boltzmann theory we study the effect of Bjerrum pairs on the typical length scale [Formula: see text] over which electric fields are screened in electrolyte solutions, taking into account a simple association-dissociation equilibrium between free ions and Bjerrum pairs. At low densities of Bjerrum pairs, this length scale is well approximated by the Debye length [Formula: see text], with ρ(s) the free-ion density. At high densities of Bjerrum pairs, however, we find [Formula: see text], which is significantly larger than 1/κ due to the enhanced effective permittivity of the electrolyte, caused by the polarization of Bjerrum pairs. We argue that this mechanism may explain the recently observed anomalously large colloid-free zones between an oil-dispersed colloidal crystal and a colloidal monolayer at the oil-water interface.

  10. Threshold defect production in silicon determined by density functional theory molecular dynamics simulations

    International Nuclear Information System (INIS)

    Holmstroem, E.; Kuronen, A.; Nordlund, K.

    2008-01-01

    We studied threshold displacement energies for creating stable Frenkel pairs in silicon using density functional theory molecular dynamics simulations. The average threshold energy over all lattice directions was found to be 36±2 STAT ±2 SYST eV, and thresholds in the directions and were found to be 20±2 SYST eV and 12.5±1.5 SYST eV, respectively. Moreover, we found that in most studied lattice directions, a bond defect complex is formed with a lower threshold than a Frenkel pair. The average threshold energy for producing either a bond defect or a Frenkel pair was found to be 24±1 STAT ±2 SYST eV

  11. Microscopically based energy density functionals for nuclei using the density matrix expansion. II. Full optimization and validation

    Science.gov (United States)

    Navarro Pérez, R.; Schunck, N.; Dyhdalo, A.; Furnstahl, R. J.; Bogner, S. K.

    2018-05-01

    Background: Energy density functional methods provide a generic framework to compute properties of atomic nuclei starting from models of nuclear potentials and the rules of quantum mechanics. Until now, the overwhelming majority of functionals have been constructed either from empirical nuclear potentials such as the Skyrme or Gogny forces, or from systematic gradient-like expansions in the spirit of the density functional theory for atoms. Purpose: We seek to obtain a usable form of the nuclear energy density functional that is rooted in the modern theory of nuclear forces. We thus consider a functional obtained from the density matrix expansion of local nuclear potentials from chiral effective field theory. We propose a parametrization of this functional carefully calibrated and validated on selected ground-state properties that is suitable for large-scale calculations of nuclear properties. Methods: Our energy functional comprises two main components. The first component is a non-local functional of the density and corresponds to the direct part (Hartree term) of the expectation value of local chiral potentials on a Slater determinant. Contributions to the mean field and the energy of this term are computed by expanding the spatial, finite-range components of the chiral potential onto Gaussian functions. The second component is a local functional of the density and is obtained by applying the density matrix expansion to the exchange part (Fock term) of the expectation value of the local chiral potential. We apply the UNEDF2 optimization protocol to determine the coupling constants of this energy functional. Results: We obtain a set of microscopically constrained functionals for local chiral potentials from leading order up to next-to-next-to-leading order with and without three-body forces and contributions from Δ excitations. These functionals are validated on the calculation of nuclear and neutron matter, nuclear mass tables, single-particle shell structure

  12. Development of the Advanced Energetic Pair Telescope (AdEPT) for Medium-Energy Gamma-Ray Astronomy

    Science.gov (United States)

    Hunter, Stanley D.; Bloser, Peter F.; Dion, Michael P.; McConnell, Mark L.; deNolfo, Georgia A.; Son, Seunghee; Ryan, James M.; Stecker, Floyd W.

    2011-01-01

    Progress in high-energy gamma-ray science has been dramatic since the launch of INTEGRAL, AGILE and FERMI. These instruments, however, are not optimized for observations in the medium-energy (approx.0.3< E(sub gamma)< approx.200 MeV) regime where many astrophysical objects exhibit unique, transitory behavior, such as spectral breaks, bursts, and flares. We outline some of the major science goals of a medium-energy mission. These science goals are best achieved with a combination of two telescopes, a Compton telescope and a pair telescope, optimized to provide significant improvements in angular resolution and sensitivity. In this paper we describe the design of the Advanced Energetic Pair Telescope (AdEPT) based on the Three-Dimensional Track Imager (3-DTI) detector. This technology achieves excellent, medium-energy sensitivity, angular resolution near the kinematic limit, and gamma-ray polarization sensitivity, by high resolution 3-D electron tracking. We describe the performance of a 30x30x30 cm3 prototype of the AdEPT instrument.

  13. Thermodynamics of pairing phase transition in nuclei

    International Nuclear Information System (INIS)

    Karim, Afaque; Ahmad, Shakeb

    2014-01-01

    The pairing gaps, pairing energy, heat capacity and entropy are calculated within BCS (Bardeen- Cooper-Schrieffer) based quasi particle approach, including thermal fluctuations on pairing field within pairing model for all nuclei (light, medium, heavy and super heavy nuclei). Quasi particles approach in BCS theory was introduced and reformulated to study various properties. For thermodynamic behavior of nuclei at finite temperatures, the anomalous averages of creation and annihilation operators are introduced. It is solved self consistently at finite temperatures to obtain BCS Hamiltonian. After doing unitary transformation, we obtained the Hamiltonian in the diagonal form. Thus, one gets temperature dependence gap parameter and pairing energy for nuclei. Moreover, the energy at finite temperatures is the sum of the condensation energy and the thermal energy of fermionic quasi particles. With the help of BCS Hamiltonian, specific heat, entropy and free energy are calculated for different nuclei. In this paper the gap parameter occupation number and pairing energy as a function of temperature which is important for all the light, medium, heavy and super heavy nuclei is calculated. Moreover, the various thermo dynamical quantities like specific heat, entropy and free energy is also obtained for different nuclei. Thus, the thermodynamics of pairing phase transition in nuclei is studied

  14. On adiabatic pair potentials of highly charged colloid particles

    Science.gov (United States)

    Sogami, Ikuo S.

    2018-03-01

    Generalizing the Debye-Hückel formalism, we develop a new mean field theory for adiabatic pair potentials of highly charged particles in colloid dispersions. The unoccupied volume and the osmotic pressure are the key concepts to describe the chemical and thermodynamical equilibrium of the gas of small ions in the outside region of all of the colloid particles. To define the proper thermodynamic quantities, it is postulated to take an ensemble averaging with respect to the particle configurations in the integrals for their densities consisting of the electric potential satisfying a set of equations that are derived by linearizing the Poisson-Boltzmann equation. With the Fourier integral representation of the electric potential, we calculate first the internal electric energy of the system from which the Helmholtz free energy is obtained through the Legendre transformation. Then, the Gibbs free energy is calculated using both ways of the Legendre transformation with respect to the unoccupied volume and the summation of chemical potentials. The thermodynamic functions provide three types of pair potentials, all of which are inversely proportional to the fraction of the unoccupied volume. At the limit when the fraction factor reduces to unity, the Helmholtz pair potential turns exactly into the well known Derjaguin-Landau-Verwey-Overbeek repulsive potential. The Gibbs pair potential possessing a medium-range strong repulsive part and a long-range weak attractive tail can explain the Schulze-Hardy rule for coagulation in combination with the van der Waals-London potential and describes a rich variety of phenomena of phase transitions observed in the dilute dispersions of highly charged particles.

  15. On the kinetic energy density

    International Nuclear Information System (INIS)

    Lombard, R.J.; Mas, D.; Moszkowski, S.A.

    1991-01-01

    We discuss two expressions for the density of kinetic energy which differ by an integration by parts. Using the Wigner transform we shown that the arithmetic mean of these two terms is closely analogous to the classical value. Harmonic oscillator wavefunctions are used to illustrate the radial dependence of these expressions. We study the differences they induce through effective mass terms when performing self-consistent calculations. (author)

  16. Pair creation at large inherent angles

    International Nuclear Information System (INIS)

    Chen, P.; Tauchi, T.; Schroeder, D.V.

    1992-01-01

    In the next-generation linear colliders, the low-energy e + e - pairs created during the collision of high-energy e + e - beams would cause potential deleterious background problems to the detectors. At low collider energies, the pairs are made essentially by the incoherent process, where the pair is created by the interaction of beamstrahlung photons on the individual particles in the oncoming beam. This problem was first identified by Zolotarev, et al. At energies where the beamstrahlung parameter Υ lies approximately in the range 0.6 approx-lt Υ approx-lt 100, pair creation from the beamstrahlung photons is dominated by a coherent process, first noted by Chen. The seriousness of this pair creation problem lies in the transverse momenta that the pair particles carry when leaving the interaction point (IP) with large angles. Since the central issue is the transverse momentum for particles with large angles, the authors notice that there is another source for it. Namely, when the pair particles are created at low energies, the intrinsic angles of these pairs when produced may already be large. In this paper they reinvestigate the problem, following essentially the same equivalent photon approach, but with changes in specific details including the virtual photon spectrum. In addition, various assumptions are made more explicit. The formulas derived are then applied to the collider parameters designed by Palmer

  17. Comparison of renewable fuels based on their land use using energy densities

    NARCIS (Netherlands)

    Dijkman, T. J.; Benders, R. M. J.

    2010-01-01

    In this article energy densities of selected renewable fuels are determined. Energy density is defined here as the annual energy production per hectare, taking energy inputs into account. Using 5 scenarios, consisting of 1 set focusing on technical differences and 1 set focusing on geographical

  18. Pair correlations in an expanding universe for a multicomponent system

    International Nuclear Information System (INIS)

    Kandrup, H.E.

    1983-01-01

    Fall and Saslaw have derived an equation for the growth of pair correlations in an expanding universe of identical self-gravitating point masses which is correlation-free at some initial time. Their equation is rigorously true for the earliest stages of growth, assuming only that the system is spatially homogeneous and isotropic, and that it is characterized in the ''comoving frame'' by a Maxwellian distribution of velocities. This paper generalizes their analysis to the case of a multicomponent system of particles with different masses, each species of which is characterized by a Maxwellian distribution at the same temperature. Here there are two types of pair correlations to consider, namely among members of the same species and among members of different species. The general behavior may be understood most readily by considering the covariance functions, which assume very simple forms. Thus one finds that the ''strength'' of the covariance scales, for sufficiently small radial separations, as the product of the masses, whereas the ''range'' of the covariance varies inversely as the square root of the reduced mass of the two constituents. This implies that, for two very different masses, the ''range'' will be set by the lighter constituent. Knowledge of the covariances also permits the calculation of such objects as the correlational energy densities of the various interactions. Consider, for example, a two-component system. Here one finds that even a very small contamination of heavy masses, which would have a negligible effect upon the total mass or kinetic energy densities, can increase the total correlational energy density, and hence decrease the time scale for the evolution of interesting structure, by orders of magnitude

  19. High-energy density physics at Los Alamos

    International Nuclear Information System (INIS)

    Byrnes, P.; Younger, S.M.

    1993-03-01

    This brochure describes the facilities of the Above Ground Experiments II (AGEX II) and the Inertial Confinement Fusion (ICF) programs at Los Alamo. Combined, these programs represent, an unparalleled capability to address important issues in high-energy density physics that are critical to the future defense, energy, and research needs of th e United States. The mission of the AGEX II program at Los Alamos is to provide additional experimental opportunities for the nuclear weapons program. For this purpose we have assembled at Los Alamos the broadest array of high-energy density physics facilities of any laboratory in the world. Inertial confinement fusion seeks to achieve thermonuclear burn on a laboratory scale through the implosion of a small quantity of deuterium and tritium fuel to very high Pressure and temperature.The Los Alamos ICF program is focused on target physics. With the largest scientific computing center in the world, We can perform calculations of unprecedented sophistication and precision. We field experiments at facilities worldwide-including our own Trident and Mercury lasers-to confirm our understanding and to provide the necessary data base to proceed toward the historic goal of controlled fusion in the laboratory. In addition to direct programmatic high-energy density physics is a nc scientific endeavor in itself. The ultrahigh magnetic fields produced in our high explosive pulsed-power generators can be used in awide variety of solid state physics and temperature superconductor studies. The structure and dynamics of planetary atmospheres can be simulated through the compression of gas mixtures

  20. Towards a sustainable global energy supply infrastructure: Net energy balance and density considerations

    International Nuclear Information System (INIS)

    Kessides, Ioannis N.; Wade, David C.

    2011-01-01

    This paper employs a framework of dynamic energy analysis to model the growth potential of alternative electricity supply infrastructures as constrained by innate physical energy balance and dynamic response limits. Coal-fired generation meets the criteria of longevity (abundance of energy source) and scalability (ability to expand to the multi-terawatt level) which are critical for a sustainable energy supply chain, but carries a very heavy carbon footprint. Renewables and nuclear power, on the other hand, meet both the longevity and environmental friendliness criteria. However, due to their substantially different energy densities and load factors, they vary in terms of their ability to deliver net excess energy and attain the scale needed for meeting the huge global energy demand. The low power density of renewable energy extraction and the intermittency of renewable flows limit their ability to achieve high rates of indigenous infrastructure growth. A significant global nuclear power deployment, on the other hand, could engender serious risks related to proliferation, safety, and waste disposal. Unlike renewable sources of energy, nuclear power is an unforgiving technology because human lapses and errors can have ecological and social impacts that are catastrophic and irreversible. Thus, the transition to a low carbon economy is likely to prove much more challenging than early optimists have claimed. - Highlights: → We model the growth potential of alternative electricity supply infrastructures. → Coal is scalable and abundant but carries a heavy carbon footprint. → Renewables and nuclear meet the longevity and environmental friendliness criteria. → The low power density and intermittency of renewables limit their growth potential. → Nuclear power continues to raise concerns about proliferation, safety, and waste.

  1. Off-shell pairing correlations from meson-exchange theory of nuclear forces

    International Nuclear Information System (INIS)

    Sedrakian, Armen

    2003-01-01

    We develop a model of off-mass-shell pairing correlations in nuclear systems, which is based on the meson-exchange picture of nuclear interactions. The temporal retardations in the model are generated by the Fock-exchange diagrams. The kernel of the complex gap equation for baryons is related to the in-medium spectral function of mesons, which is evaluated nonperturbatively in the random phase approximation. The model is applied to the low-density neutron matter in neutron star crusts by separating the interaction into a long-range one-pion-exchange component and a short-range component parametrized in terms of Landau Fermi liquid parameters. The resulting Eliashberg-type coupled nonlinear integral equations are solved by an iterative procedure. We find that the self-energies extend to off-shell energies of the order of several tens of MeV. At low energies the damping of the neutron pair correlations due to the coupling to the pionic modes is small, but becomes increasingly important as the energy is increased. We discuss an improved quasiclassical approximation under which the numerical solutions are obtained

  2. Strain Energy Density in the Elastodynamics of the Spacetime Continuum and the Electromagnetic Field

    Directory of Open Access Journals (Sweden)

    Millette P. A.

    2013-04-01

    Full Text Available We investigate the strain energy density of the spacetime continuum in the Elasto- dynamics of the Spacetime Continuum by applying continuum m echanical results to strained spacetime. The strain energy density is a scalar. W e find that it is separated into two terms: the first one expresses the dilatation energy density (the “mass” longitu- dinal term while the second one expresses the distortion en ergy density (the “massless” transverse term. The quadratic structure of the energy rel ation of Special Relativity is found to be present in the theory. In addition, we find that the kinetic energy pc is car- ried by the distortion part of the deformation, while the dil atation part carries only the rest-mass energy. The strain energy density of the electrom agnetic energy-momentum stress tensor is calculated. The dilatation energy density (the rest-mass energy density of the photon is found to be 0 as expected. The transverse dis tortion energy density is found to include a longitudinal electromagnetic energy fl ux term, from the Poynting vector, that is massless as it is due to distortion, not dilatation, of the spacetime con- tinuum. However, because this energy flux is along the direct ion of propagation (i.e. longitudinal, it gives rise to the particle aspect of the el ectromagnetic field, the photon.

  3. Coefficient of friction of a starved lubricated spur gear pair

    International Nuclear Information System (INIS)

    Liu, Huaiju; Zhu, Caichao; Sun, Zhangdong; Zhang, Yuanyuan; Song, Chaosheng

    2016-01-01

    The frictional power loss issue of gear pairs becomes an important concern in both industry and academia due to the requirement of the energy saving and the improvement of power density of gear drives. A thermal starved elastohydrodynamic lubrication model is developed to study the tribological performance of a spur gear pair under starved lubrication conditions. The contact pressure, the film thickness, the temperature rise, the frictional power loss, as well as the coefficient of friction are evaluated by considering the variation of the curvature radius, the sliding/rolling motion, and the load distribution of gear tooth within the meshing period. Effects of lubrication starvation condition, load and speed on the coefficient of friction are studied.

  4. Estimation of energy density of Li-S batteries with liquid and solid electrolytes

    Science.gov (United States)

    Li, Chunmei; Zhang, Heng; Otaegui, Laida; Singh, Gurpreet; Armand, Michel; Rodriguez-Martinez, Lide M.

    2016-09-01

    With the exponential growth of technology in mobile devices and the rapid expansion of electric vehicles into the market, it appears that the energy density of the state-of-the-art Li-ion batteries (LIBs) cannot satisfy the practical requirements. Sulfur has been one of the best cathode material choices due to its high charge storage (1675 mAh g-1), natural abundance and easy accessibility. In this paper, calculations are performed for different cell design parameters such as the active material loading, the amount/thickness of electrolyte, the sulfur utilization, etc. to predict the energy density of Li-S cells based on liquid, polymeric and ceramic electrolytes. It demonstrates that Li-S battery is most likely to be competitive in gravimetric energy density, but not volumetric energy density, with current technology, when comparing with LIBs. Furthermore, the cells with polymer and thin ceramic electrolytes show promising potential in terms of high gravimetric energy density, especially the cells with the polymer electrolyte. This estimation study of Li-S energy density can be used as a good guidance for controlling the key design parameters in order to get desirable energy density at cell-level.

  5. An atlas of RNA base pairs involving modified nucleobases with optimal geometries and accurate energies

    KAUST Repository

    Chawla, Mohit

    2015-06-27

    Posttranscriptional modifications greatly enhance the chemical information of RNA molecules, contributing to explain the diversity of their structures and functions. A significant fraction of RNA experimental structures available to date present modified nucleobases, with half of them being involved in H-bonding interactions with other bases, i.e. ‘modified base pairs’. Herein we present a systematic investigation of modified base pairs, in the context of experimental RNA structures. To this end, we first compiled an atlas of experimentally observed modified base pairs, for which we recorded occurrences and structural context. Then, for each base pair, we selected a representative for subsequent quantum mechanics calculations, to find out its optimal geometry and interaction energy. Our structural analyses show that most of the modified base pairs are non Watson–Crick like and are involved in RNA tertiary structure motifs. In addition, quantum mechanics calculations quantify and provide a rationale for the impact of the different modifications on the geometry and stability of the base pairs they participate in.

  6. An atlas of RNA base pairs involving modified nucleobases with optimal geometries and accurate energies

    KAUST Repository

    Chawla, Mohit; Oliva, R.; Bujnicki, J. M.; Cavallo, Luigi

    2015-01-01

    Posttranscriptional modifications greatly enhance the chemical information of RNA molecules, contributing to explain the diversity of their structures and functions. A significant fraction of RNA experimental structures available to date present modified nucleobases, with half of them being involved in H-bonding interactions with other bases, i.e. ‘modified base pairs’. Herein we present a systematic investigation of modified base pairs, in the context of experimental RNA structures. To this end, we first compiled an atlas of experimentally observed modified base pairs, for which we recorded occurrences and structural context. Then, for each base pair, we selected a representative for subsequent quantum mechanics calculations, to find out its optimal geometry and interaction energy. Our structural analyses show that most of the modified base pairs are non Watson–Crick like and are involved in RNA tertiary structure motifs. In addition, quantum mechanics calculations quantify and provide a rationale for the impact of the different modifications on the geometry and stability of the base pairs they participate in.

  7. Full charge-density calculation of the surface energy of metals

    DEFF Research Database (Denmark)

    Vitos, Levente; Kollár, J..; Skriver, Hans Lomholt

    1994-01-01

    of a spherically symmetrized charge density, while the Coulomb and exchange-correlation contributions are calculated by means of the complete, nonspherically symmetric charge density within nonoverlapping, space-filling Wigner-Seitz cells. The functional is used to assess the convergence and the accuracy......We have calculated the surface energy and the work function of the 4d metals by means of an energy functional based on a self-consistent, spherically symmetric atomic-sphere potential. In this approach the kinetic energy is calculated completely within the atomic-sphere approximation (ASA) by means...... of the linear-muffin-tin-orbitals (LMTO) method and the ASA in surface calculations. We find that the full charge-density functional improves the agreement with recent full-potential LMTO calculations to a level where the average deviation in surface energy over the 4d series is down to 10%....

  8. Kinetic-energy density functional: Atoms and shell structure

    International Nuclear Information System (INIS)

    Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E.

    1996-01-01

    We present a nonlocal kinetic-energy functional which includes an anisotropic average of the density through a symmetrization procedure. This functional allows a better description of the nonlocal effects of the electron system. The main consequence of the symmetrization is the appearance of a clear shell structure in the atomic density profiles, obtained after the minimization of the total energy. Although previous results with some of the nonlocal kinetic functionals have given incipient structures for heavy atoms, only our functional shows a clear shell structure for most of the atoms. The atomic total energies have a good agreement with the exact calculations. Discussion of the chemical potential and the first ionization potential in atoms is included. The functional is also extended to spin-polarized systems. copyright 1996 The American Physical Society

  9. Electroweak Measurements in Electron-Positron Collisions at W-Boson-Pair Energies at LEP

    CERN Document Server

    Schael, S.; Bruneliere, R.; Buskulic, D.; De Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Jezequel, S.; Lees, J.P.; Lucotte, A.; Martin, F.; Merle, E.; Minard, M.N.; Nief, J.Y.; Odier, P.; Pietrzyk, B.; Trocme, B.; Bravo, S.; Casado, M.P.; Chmeissani, M.; Comas, P.; Crespo, J.M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Grauges, E.; Juste, A.; Martinez, M.; Merino, G.; Miquel, R.; Mir, Ll. M.; Orteu, S.; Pacheco, A.; Park, I.C.; Perlas, J.; Riu, I.; Ruiz, H.; Sanchez, F.; Colaleo, A.; Creanza, D.; De Filippis, N.; De Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Bazarko, A.; Becker, U.; Boix, G.; Bird, F.; Blucher, E.; Bonvicini, B.; Bright-Thomas, P.; Barklow, T.; Buchmuller, O.; Cattaneo, M.; Cerutti, F.; Ciulli, V.; Clerbaux, B.; Drevermann, H.; Forty, R.W.; Frank, M.; Greening, T.C.; Hagelberg, R.; Halley, A.W.; Gianotti, F.; Girone, M.; Hansen, J.B.; Harvey, J.; Jacobsen, R.; Hutchcroft, D.E.; Janot, P.; Jost, B.; Knobloch, J.; Kado, M.; Lehraus, I.; Lazeyras, P.; Maley, P.; Mato, P.; May, J.; Moutoussi, A.; Pepe-Altarelli, M.; Ranjard, F.; Rolandi, L.; Schlatter, D.; Schmitt, B.; Schneider, O.; Tejessy, W.; Teubert, F.; Tomalin, I.R.; Tournefier, E.; Veenhof, R.; Valassi, A.; Wiedenmann, W.; Wright, A.E.; Ajaltouni, Z.; Badaud, F.; Chazelle, G.; Deschamps, O.; Dessagne, S.; Falvard, A.; Ferdi, C.; Fayolle, D.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.C.; Pallin, D.; Pascolo, J.M.; Perret, P.; Podlyski, F.; Bertelsen, H.; Fernley, T.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Kraan, A.C.; Lindahl, A.; Mollerud, R.; Nilsson, B.S.; Rensch, B.; Waananen, A.; Daskalakis, G.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J.C.; Machefert, F.; Rouge, A.; Rumpf, M.; Swynghedauw, M.; Tanaka, R.; Verderi, M.; Videau, H.; Ciulli, V.; Focardi, E.; Parrini, G.; Zachariadou, K.; Corden, M.; Georgiopoulos, C.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, G.P.; Passalacqua, L.; Picchi, P.; Colrain, P.; ten Have, I.; Hughes, I.S.; Kennedy, J.; Knowles, I.G.; Lynch, J.G.; Morton, W.T.; Negus, P.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J.M.; Smith, K.; Thompson, A.S.; Turnbull, R.M.; Wasserbaech, S.; Buchmuller, O.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E.E.; Putzer, A.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, W.; Wunsch, M.; Beuselinck, R.; Binnie, D.M.; Cameron, W.; Davies, G.; Dornan, P.J.; Goodsir, S.; Marinelli, N.; Martin, E.B.; Nash, J.; Nowell, J.; Rutherford, S.A.; Sedgbeer, J.K.; Thompson, J.C.; White, R.; Williams, M.D.; Ghete, V.M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bouhova-Thacker, E.; Bowdery, C.K.; Buck, P.G.; Clarke, D.P.; Ellis, G.; Finch, A.J.; Foster, F.; Hughes, G.; Jones, R.W.L.; Keemer, N.R.; Pearson, M.R.; Robertson, N.A.; Sloan, T.; Smizanska, M.; Snow, S.W.; Williams, M.I.; van der Aa, O.; Delaere, C.; Leibenguth, G.; Lemaitre, V.; Bauerdick, L.A.T.; Blumenschein, U.; van Gemmeren, P.; Giehl, I.; Holldorfer, F.; Jakobs, K.; Kasemann, M.; Kayser, F.; Kleinknecht, K.; Muller, A.S.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.G.; Schmeling, S.; Wachsmuth, H.; Wanke, R.; Zeitnitz, C.; Ziegler, T.; Aubert, J.J.; Benchouk, C.; Bonissent, A.; Carr, J.; Coyle, P.; Curtil, C.; Ealet, A.; Etienne, F.; Fouchez, D.; Motsch, F.; Payre, P.; Rousseau, D.; Tilquin, A.; Talby, M.; Thulasidas, M.; Aleppo, M.; Antonelli, M.; Ragusa, F.; Buscher, V.; David, A.; Dietl, H.; Ganis, G.; Huttmann, K.; Lutjens, G.; Mannert, C.; Manner, W.; Moser, H.G.; Settles, R.; Seywerd, H.; Stenzel, H.; Villegas, M.; Wiedenmann, W.; Wolf, G.; Azzurri, P.; Boucrot, J.; Callot, O.; Chen, S.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.F.; Heusse, Ph.; Jacholkowska, A.; Le Diberder, F.; Lefrancois, J.; Mutz, A.M.; Schune, M.H.; Serin, L.; Veillet, J.J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, G.; Bettarini, S.; Boccali, T.; Bozzi, C.; Calderini, G.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Fidecaro, F.; Foa, L.; Giammanco, A.; Giassi, A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P.S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Sciaba, A.; Sguazzoni, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Vannini, C.; Venturi, A.; Verdini, P.G.; Awunor, O.; Blair, G.A.; Cowan, G.; Garcia-Bellido, A.; Green, M.G.; Medcalf, T.; Misiejuk, A.; Strong, J.A.; Teixeira-Dias, P.; Botterill, D.R.; Clifft, R.W.; Edgecock, T.R.; Edwards, M.; Haywood, S.J.; Norton, P.R.; Tomalin, I.R.; Ward, J.J.; Bloch-Devaux, B.; Boumediene, D.; Colas, P.; Emery, S.; Fabbro, B.; Kozanecki, W.; Lancon, E.; Lemaire, M.C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.F.; Roussarie, A.; Schuller, J.P.; Schwindling, J.; Tuchming, B.; Vallage, B.; Black, S.N.; Dann, J.H.; Kim, H.Y.; Konstantinidis, N.; Litke, A.M.; McNeil, M.A.; Taylor, G.; Booth, C.N.; Cartwright, S.; Combley, F.; Hodgson, P.N.; Lehto, M.; Thompson, L.F.; Affholderbach, K.; Barberio, E.; Bohrer, A.; Brandt, S.; Burkhardt, H.; Feigl, E.; Grupen, C.; Hess, J.; Lutters, G.; Meinhard, H.; Minguet-Rodriguez, J.; Mirabito, L.; Misiejuk, A.; Neugebauer, E.; Ngac, A.; Prange, G.; Rivera, F.; Saraiva, P.; Schafer, U.; Sieler, U.; Smolik, L.; Stephan, F.; Trier, H.; Apollonio, M.; Borean, C.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Pitis, L.; He, H.; Kim, H.; Putz, J.; Rothberg, J.; Armstrong, S.R.; Bellantoni, L.; Berkelman, K.; Cinabro, D.; Conway, J.S.; Cranmer, K.; Elmer, P.; Feng, Z.; Ferguson, D.P.S.; Gao, Y.; Gonzalez, S.; Grahl, J.; Harton, J.L.; Hayes, O.J.; Hu, H.; Jin, S.; Johnson, R.P.; Kile, J.; McNamara, P.A., III; Nielsen, J.; Orejudos, W.; Pan, Y.B.; Saadi, Y.; Scott, I.J.; Sharma, V.; Walsh, A.M.; Walsh, J.; Wear, J.; von Wimmersperg-Toeller, J.H.; Wiedenmann, W.; Wu, J.; Wu, S.L.; Wu, X.; Yamartino, J.M.; Zobernig, G.; Dissertori, G.; Abdallah, J.; Abreu, P.; Adam, W.; Adzic, P.; Albrecht, T.; Alemany-Fernandez, R.; Allmendinger, T.; Allport, P.P.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W-D.; Arnoud, Y.; Ask, S.; Asman, B.; Augustin, J.E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D.; Barker, G.J.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K-H.; Begalli, M.; Behrmann, A.; Belous, K.; Ben-Haim, E.; Benekos, N.; Benvenuti, A.; Berat, C.; Berggren, M.; Berntzon, L.; Bertrand, D.; Besancon, M.; Besson, N.; Bloch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P.S.L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T.J.V.; Boyko, I.; Bracko, M.; Brenner, R.; Brodet, E.; Bruckman, P.; Brunet, J.M.; Bugge, L.; Buschbeck, B.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, N.; Cavallo, F.; Chapkin, M.; Charpentier, Ph.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Cieslik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M.J.; Crawley, B.; Crennell, D.; Cuevas, J.; D'Hondt, J.; Dalmau, J.; da Silva, T.; Da Silva, W.; Della Ricca, G.; De Angelis, A.; De Boer, W.; De Clercq, C.; De Lotto, B.; De Maria, N.; De Min, A.; De Paula, L.; Di Ciaccio, L.; Di Simone, A.; Doroba, K.; Drees, J.; Dris, M.; Duperrin, A.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Espirito Santo, M.C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; Garcia, C.; Gavillet, Ph.; Gazis, E.; Gele, D.; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Herr, H.; Hoffman, J.; Holmgren, S-O.; Holt, P.J.; Houlden, M.A.; Hultqvist, K.; Jackson, J.N.; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, E.K.; Johansson, P.D.; Jonsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kersevan, B.P.; Kerzel, U.; Kiiskinen, A.; King, B.T.; Kjaer, N.J.; Kluit, P.; Kokkinias, P.; Kostioukhine, V.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lamsa, J.; Leder, G.; Ledroit, F.; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Libby, J.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J.H.; Lopez, J.M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J-C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; Nulty, R.Mc; Meroni, C.; Meyer, W.T.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Moenig, K.; Monge, R.; Montenegro, J.; Moraes, D.; Morettini, P.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.; Nawrocki, K.; Nemecek, S.; Nicolaidou, R.; Nikolaenko, V.; Nikolenko, M.; Oblakowska-Mucha, A.; Obraztsov, V.; Olshevski, A.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J.P.; Palka, H.; Papadopoulou, Th. D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Podobnik, T.; Poireau, V.; Pol, M.E.; Polok, G.; Poropat, P.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Radojicic, D.; Rames, J.; Ramler, L.; Read, A.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Ridky, J.; Ripp-Baudot, I.; Rivero, M.; Rodriguez, D.; Romero, A.; Ronchese, P.; Rosenberg, E.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Sander, C.; Savoy-Navarro, A.; Schwickerath, U.; Segar, A.; Sekulin, R.; Siebel, M.; Simard, L.; Sisakian, A.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Taffard, A.C.; Tegenfeldt, F.; Terranova, F.; Thomas, J.; Timmermans, J.; Tkatchev, L.; Tobin, M.; Todorovova, S.; Tome, B.; Tonazzo, A.; Tortosa, P.; Travnicek, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M-L.; Tyapkin, I.A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; Van Dam, P.; Van Eldik, J.; Van Lysebetten, A.; van Remortel, N.; Van Vulpen, I.; Vegni, G.; Veloso, F.; Venus, W.; Verbeure, F.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A.J.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zhuravlov, V.; Zimine, N.I.; Zintchenko, A.; Achard, P.; Adriani, O.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, V.P.; Anselmo, F.; Arefiev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; De Asmundis, R.; D'eglon, P.; Debreczeni, J.; Degre, A.; Dehmelt, K.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duda, M.; Echenard, B.; Eline, A.; El Hage, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Yu.; Ganguli, S.N.; Garcia-Abia, P.; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, G.; Grimm, O.; Gruenewald, M.W.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, A.; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Jin, B.N.; Jindal, P.; Jones, L.W.; de Jong, P.; Josa-Mutuberria, I.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, J.; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, M.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Nisati, A.; Novak, T.; Nowak, H.; Ofierzynski, R.; Organtini, G.; Palomares, C.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, T.; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Piccolo, D.; Pierella, F.; Pieri, M.; Pioppi, M.; Pirou'e, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofiev, D.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Rembeczki, S.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, K.; Roe, B.P.; Romero, L.; Rosca, A.; Rosemann, C.; Rosenbleck, C.; Rosier-Lees, S.; Roth, S.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Schafer, C.; Schegelsky, V.; Schopper, H.; Schotanus, D.J.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Son, D.; Souga, C.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, C.; Ting, S.C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Vasquez, R.; Vesztergombi, G.; Vetlitsky, I.; Viertel, G.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A.A.; Wadhwa, M.; Wang, Q.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, An.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zimmermann, B.; Zoller, M.; Abbiendi, G.; Ackerstaff, K.; Ainsley, C.; Akesson, P.F.; Alexander, G.; Allison, J.; Altekamp, N.; Ametewee, K.; Anagnostou, G.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Bartoldus, R.; Batley, R.J.; Baumann, S.; Bechtle, P.; Bechtluft, J.; Beeston, C.; Behnke, T.; Bell, K.W.; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bentvelsen, S.; Berlich, P.; Bethke, S.; Biebel, O.; Boeriu, O.; Blobel, V.; Bloodworth, I.J.; Bloomer, J.E.; Bobinski, M.; Bock, P.; Bonacorsi, D.; Bosch, H.M.; Boutemeur, M.; Bouwens, B.T.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, R.M.; Burckhart, H.J.; Burgard, C.; Burgin, R.; Cammin, J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couchman, J.; Couyoumtzelis, C.; Coxe, R.L.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallapiccola, C.; Dallavalle, M.; Dallison, S.; de Jong, S.; De Roeck, A.; Dervan, P.; De Wolf, E.A.; del Pozo, L.A.; Desch, K.; Dienes, B.; Dixit, M.S.; do Couto e Silva, E.; Donkers, M.; Doucet, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Edwards, J.E.G.; Estabrooks, P.G.; Etzion, E.; Evans, H.G.; Evans, M.; Fabbri, F.; Fanti, M.; Fath, P.; Feld, L.; Ferrari, P.; Fiedler, F.; Fierro, M.; Fischer, H.M.; Fleck, I.; Folman, R.; Fong, D.G.; Ford, M.; Foucher, M.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Gaycken, G.; Geddes, N.I.; Geich-Gimbel, C.; Geralis, T.; Giacomelli, G.; Giacomelli, P.; Giacomelli, R.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Giunta, M.; Glenzinski, D.; Goldberg, J.; Goodrick, M.J.; Gorn, W.; Graham, K.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Harin-Dirac, M.; Hart, P.A.; Hartmann, C.; Hauke, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hillier, S.J.; Hilse, T.; Hobson, P.R.; Hocker, A.; Hoffman, K.; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Hughes-Jones, R.E.; Huntemeyer, P.; Hutchcroft, D.E.; Igo-Kemenes, P.; Imrie, D.C.; Ingram, M.R.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeffreys, P.W.; Jeremie, H.; Jimack, M.; Joly, A.; Jones, C.R.; Jones, G.; Jones, M.; Jones, R.W.L.; Jost, U.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; King, B.J.; Kirk, J.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D.S.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, R.V.; Kramer, T.; Krasznahorkay, A., Jr.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Lahmann, R.; Lai, W.P.; Landsman, H.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lefebvre, E.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Lewis, C.; Liebisch, R.; Lillich, J.; List, B.; List, J.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, A.; Ludwig, J.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Marchant, T.E.; Markus, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Matthews, W.; Mattig, P.; McDonald, W.J.; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McNab, A.I.; McPherson, R.A.; Mendez-Lorenzo, P.; Meijers, F.; Menges, W.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, N.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Morii, M.; Muller, U.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nellen, B.; Nijjhar, B.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oh, A.; Okpara, A.; Oldershaw, N.J.; Omori, T.; Oreglia, M.J.; Orito, S.; Pahl, C.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Pearce, M.J.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, D.E.; Poffenberger, P.; Polok, J.; Poli, B.; Pooth, O.; Posthaus, A.; Przybycien, M.; Przysiezniak, H.; Quadt, A.; Rabbertz, K.; Rees, D.L.; Rembser, C.; Renkel, P.; Rick, H.; Rigby, D.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rooke, A.; Ros, E.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rosvick, M.; Routenburg, P.; Rozen, Y.; Runge, K.; Runolfsson, O.; Ruppel, U.; Rust, D.R.; Rylko, R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Sasaki, M.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schenk, P.; Schieck, J.; Schmitt, S.; Schorner-Sadenius, T.; Schroder, M.; Schultz-Coulon, H.C.; Schulz, M.; Schumacher, M.; Schutz, P.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skillman, A.; Skuja, A.; Smith, A.M.; Smith, T.J.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Spano, F.; Springer, R.W.; Sproston, M.; Stahl, A.; Steiert, M.; Stephens, K.; Steuerer, J.; Stockhausen, B.; Stoll, K.; Strom, D.; Strohmer, R.; Strumia, F.; Stumpf, L.; Surrow, B.; Szymanski, P.; Tafirout, R.; Talbot, S.D.; Tanaka, S.; Taras, P.; Tarem, S.; Taylor, R.J.; Tasevsky, M.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Toya, D.; Trefzger, T.; Trigger, I.; Trocsanyi, Z.; Tsukamoto, T.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Utzat, P.; Vachon, B.; Van Kooten, R.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Vikas, P.; Vincter, M.; Vokurka, E.H.; Vollmer, C.F.; Voss, H.; Vossebeld, J.; Wackerle, F.; Wagner, A.; Waller, D.; Ward, C.P.; Ward, D.R.; Ward, J.J.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; White, J.S.; Wilkens, B.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wotton, S.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.; Zivkovic, L.

    2013-01-01

    Electroweak measurements performed with data taken at the electron-positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3~fb$^{-1}$ collected by the four LEP experiments ALEPH, DELPHI, L3 and OPAL, at centre-of-mass energies ranging from $130~GeV$ to $209~GeV$. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron-positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose-Einstein correlations between the two W decay systems arising ...

  10. Universal spectral signatures in pnictides and cuprates: the role of quasiparticle-pair coupling.

    Science.gov (United States)

    Sacks, William; Mauger, Alain; Noat, Yves

    2017-11-08

    Understanding the physical properties of a large variety of high-T c superconductors (SC), the cuprate family as well as the more recent iron-based superconductors, is still a major challenge. In particular, these materials exhibit the 'peak-dip-hump' structure in the quasiparticle density of states (DOS). The origin of this structure is explained within our pair-pair interaction (PPI) model: The non-superconducting state consists of incoherent pairs, a 'Cooper-pair glass' which, due to the PPI, undergoes a Bose-like condensation below T c to the coherent SC state. We derive the equations of motion for the quasiparticle operators showing that the DOS 'peak-dip-hump' is caused by the coupling between quasiparticles and excited pair states, or 'super-quasiparticles'. The renormalized SC gap function becomes energy-dependent and non retarded, reproducing accurately the experimental spectra of both pnictides and cuprates, despite the large difference in gap value.

  11. Scalings of energy confinement and density limit in stellarator/heliotron

    International Nuclear Information System (INIS)

    Sudo, S.; Takeiri, Y.; Zushi, H.; Sano, F.; Itoh, K.; Kondo, K.; Iiyoshi, A.

    1989-04-01

    Empirical scaling of energy confinement observed experimentally in stellarator/heliotron (Heliotron E, Wendelstein 7A, L2, Heliotron DR) under the condition that plasmas are heated by ECH and/or NbI is proposed. Empirical scaling of density limit obtainable under the optimum condition is proposed. These scalings are compared with those of tokamaks. The energy confinement scaling has similar power dependence as 'L mode scaling' of tokamaks. The density limit scaling seems also to indicate the upper limit of achievable density in many tokamaks. Combining the energy confinement time and the density limit scaling a transport-limited beta value is also deduced. Thus, from the viewpoint of designing a machine, there should be some compromise in determing magnetic field strength on plasma axis, average minor radius and major radius, because their dependence on confinement time and transport-limited beta value is contradicting. (J.P.N.)

  12. Nuclear energy density functional from chiral pion-nucleon dynamics revisited

    Science.gov (United States)

    Kaiser, N.; Weise, W.

    2010-05-01

    We use a recently improved density-matrix expansion to calculate the nuclear energy density functional in the framework of in-medium chiral perturbation theory. Our calculation treats systematically the effects from 1 π-exchange, iterated 1 π-exchange, and irreducible 2 π-exchange with intermediate Δ-isobar excitations, including Pauli-blocking corrections up to three-loop order. We find that the effective nucleon mass M(ρ) entering the energy density functional is identical to the one of Fermi-liquid theory when employing the improved density-matrix expansion. The strength F(ρ) of the ( surface-term as provided by the pion-exchange dynamics is in good agreement with that of phenomenological Skyrme forces in the density region ρ/2short-range spin-orbit interaction. The strength function F(ρ) multiplying the square of the spin-orbit density comes out much larger than in phenomenological Skyrme forces and it has a pronounced density dependence.

  13. Trivial constraints on orbital-free kinetic energy density functionals

    Science.gov (United States)

    Luo, Kai; Trickey, S. B.

    2018-03-01

    Approximate kinetic energy density functionals (KEDFs) are central to orbital-free density functional theory. Limitations on the spatial derivative dependencies of KEDFs have been claimed from differential virial theorems. We identify a central defect in the argument: the relationships are not true for an arbitrary density but hold only for the minimizing density and corresponding chemical potential. Contrary to the claims therefore, the relationships are not constraints and provide no independent information about the spatial derivative dependencies of approximate KEDFs. A simple argument also shows that validity for arbitrary v-representable densities is not restored by appeal to the density-potential bijection.

  14. High Energy Density Physics and Exotic Acceleration Schemes

    International Nuclear Information System (INIS)

    Cowan, T.; Colby, E.

    2005-01-01

    The High Energy Density and Exotic Acceleration working group took as our goal to reach beyond the community of plasma accelerator research with its applications to high energy physics, to promote exchange with other disciplines which are challenged by related and demanding beam physics issues. The scope of the group was to cover particle acceleration and beam transport that, unlike other groups at AAC, are not mediated by plasmas or by electromagnetic structures. At this Workshop, we saw an impressive advancement from years past in the area of Vacuum Acceleration, for example with the LEAP experiment at Stanford. And we saw an influx of exciting new beam physics topics involving particle propagation inside of solid-density plasmas or at extremely high charge density, particularly in the areas of laser acceleration of ions, and extreme beams for fusion energy research, including Heavy-ion Inertial Fusion beam physics. One example of the importance and extreme nature of beam physics in HED research is the requirement in the Fast Ignitor scheme of inertial fusion to heat a compressed DT fusion pellet to keV temperatures by injection of laser-driven electron or ion beams of giga-Amp current. Even in modest experiments presently being performed on the laser-acceleration of ions from solids, mega-amp currents of MeV electrons must be transported through solid foils, requiring almost complete return current neutralization, and giving rise to a wide variety of beam-plasma instabilities. As keynote talks our group promoted Ion Acceleration (plenary talk by A. MacKinnon), which historically has grown out of inertial fusion research, and HIF Accelerator Research (invited talk by A. Friedman), which will require impressive advancements in space-charge-limited ion beam physics and in understanding the generation and transport of neutralized ion beams. A unifying aspect of High Energy Density applications was the physics of particle beams inside of solids, which is proving to

  15. {lambda}{lambda} pairing in N{lambda} composite matter

    Energy Technology Data Exchange (ETDEWEB)

    Tanigawa, Tomonori [Japan Society for the Promotion of Science, Tokyo (Japan); Matsuzaki, Masayuki [Japan Atomic Energy Research Inst., Tokyo (Japan); Chiba, Satoshi [Fukuoka Univ. of Education, Dept. of Physics, Munakata, Fukuoka (Japan)

    2002-09-01

    {lambda}{lambda} pairing correlation in binary mixed matter of nucleons and lambdas is studied within the relativistic Hartree-Bogoliubov model. {lambda} hyperons to be paired up are immersed in background nucleons in normal state. A phenomenological {lambda}{lambda} interaction, which is derived relativistically from the Lagrangian of the system, is adopted to the gap equation. It is found that increasing the nucleon density makes the {lambda}{lambda} pairing gap suppressed. This result suggests a mechanism, specific to relativistic models, of its dependence on the nucleon density. (author)

  16. Pair potentials in liquid metals

    International Nuclear Information System (INIS)

    Faber, T.E.

    1980-01-01

    The argument which justifies the use of a pair potential to describe the structure-dependent term in the energy of liquid metals is briefly reviewed. Because there is an additional term in the energy which depends upon volume rather than structure, and because the pair potential itself is volume-dependent, the relationship between pair potential and observable properties such as pressure, bulk modulus and pair distribution function is more complicated for liquid metals than it is for molecular liquids. Perhaps for this reason, the agreement between pair potentials inferred from observable properties and pair potentials calculated by means of pseudo-potential theory is still far from complete. The pair potential concept is applicable only to simple liquid metals, in which the electron-ion interaction is weak. No attempt is made to discuss liquid transition and rare-earth metals, which are not simple in this sense. (author)

  17. Realistic level densities in fragment emission at high excitation energies

    International Nuclear Information System (INIS)

    Mustafa, M.G.; Blann, M.; Ignatyuk, A.V.

    1993-01-01

    Heavy fragment emission from a 44 100 Ru compound nucleus at 400 and 800 MeV of excitation is analyzed to study the influence of level density models on final yields. An approach is used in which only quasibound shell-model levels are included in calculating level densities. We also test the traditional Fermi gas model for which there is no upper energy limit to the single particle levels. We compare the influence of these two level density models in evaporation calculations of primary fragment excitations, kinetic energies and yields, and on final product yields

  18. Nucleon-nucleon correlations and the Coulomb Displacement Energy

    International Nuclear Information System (INIS)

    Van Neck, D.; Waroquier, M.; Heyde, K.

    1997-01-01

    Coulomb Displacement Energies (CDE) are accurately known for a wide range of nuclear masses. Assuming isospin independence in the nuclear Hamiltonian, the CDE can in first instance be interpreted as the Coulomb interaction energy between the density of the excess neutrons and the proton charge density in the parent nucleus. However, when using reasonable mean-field models for the proton and neutron density one underestimates the CDE by about 8% on average. This discrepancy is known as the Nolen-Schiffer anomaly, and various explanations have been put forward in the past. In this work the role of nucleon-nucleon correlations are re-examined. Calculations for the pair density functions in various nuclei are presented. Preliminary results suggest that the modifications to the mean-field pair density functions cause an enhancement of the CDE in the order of 4%, which is rather A-independent. (author)

  19. Local energy equation for two-electron atoms and relation between kinetic energy and electron densities

    International Nuclear Information System (INIS)

    March, N.H.

    2002-08-01

    In early work, Dawson and March [J. Chem. Phys. 81, 5850 (1984)] proposed a local energy method for treating both Hartree-Fock and correlated electron theory. Here, an exactly solvable model two-electron atom with pure harmonic interactions is treated in its ground state in the above context. A functional relation between the kinetic energy density t(r) at the origin r=0 and the electron density p(r) at the same point then emerges. The same approach is applied to the Hookean atom; in which the two electrons repel with Coulombic energy e 2 /r 12 , with r 12 the interelectronic separation, but are still harmonically confined. Again the kinetic energy density t(r) is the focal point, but now generalization away from r=0 is also effected. Finally, brief comments are added about He-like atomic ions in the limit of large atomic number. (author)

  20. The creation of high energy densities with antimatter beams

    International Nuclear Information System (INIS)

    Gibbs, W.R.; Kruk, J.W.; Rice Univ., Houston, TX

    1989-01-01

    The use of antiprotons (and antideuterons) for the study of the behavior of nuclear matter at high energy density is considered. It is shown that high temperatures and high energy densities can be achieved for small volumes. Also investigated is the strangeness production in antimatter annihilation. It is found that the high rate of Lambda production seen in a recent experiment is easily understood. The Lambda and K-short rapidity distributions are also reproduced by the model considered. 11 refs., 6 figs

  1. Electron-positron pair production and bremsstrahlung at intermediate energies in the field of heavy atoms

    International Nuclear Information System (INIS)

    Lee, R.N.; Milstein, A.I.; Strakhovenko, V.M.; Schwartz, O.Ya.

    2006-01-01

    The Coulomb corrections (CC) to the processes of bremsstrahlung and pair production are investigated. The next-to-leading term in the high-energy asymptotics is found. This term becomes very essential in the region of intermediate energies. The influence of screening for CC is small for differential cross section, spectrum, and the total cross section of pair production. The same is true for the spectrum of bremsstrahlung, but not for the differential cross section, where the influence of screening can be very large. The corresponding screening corrections as well as the modification of the differential cross section of bremsstrahlung are found. A comparison of our results for the total cross section of pair production with the experimental data available is performed. This comparison has justified our analytical results and allowed to elaborate a simple ansatz for the next-to-leading correction. The influence of the electron beam shape on CC for bremsstrahlung is investigated. It turns out that the differential cross section is very sensitive to this shape

  2. Solvent density inhomogeneities and solvation free energies in supercritical diatomic fluids: a density functional approach.

    Science.gov (United States)

    Husowitz, B; Talanquer, V

    2007-02-07

    Density functional theory is used to explore the solvation properties of a spherical solute immersed in a supercritical diatomic fluid. The solute is modeled as a hard core Yukawa particle surrounded by a diatomic Lennard-Jones fluid represented by two fused tangent spheres using an interaction site approximation. The authors' approach is particularly suitable for thoroughly exploring the effect of different interaction parameters, such as solute-solvent interaction strength and range, solvent-solvent long-range interactions, and particle size, on the local solvent structure and the solvation free energy under supercritical conditions. Their results indicate that the behavior of the local coordination number in homonuclear diatomic fluids follows trends similar to those reported in previous studies for monatomic fluids. The local density augmentation is particularly sensitive to changes in solute size and is affected to a lesser degree by variations in the solute-solvent interaction strength and range. The associated solvation free energies exhibit a nonmonotonous behavior as a function of density for systems with weak solute-solvent interactions. The authors' results suggest that solute-solvent interaction anisotropies have a major influence on the nature and extent of local solvent density inhomogeneities and on the value of the solvation free energies in supercritical solutions of heteronuclear molecules.

  3. Electron-hole pair effects in methane dissociative chemisorption on Ni(111)

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Xuan; Jiang, Bin, E-mail: bjiangch@ustc.edu.cn [Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Juaristi, J. Iñaki [Centro de Física de Materiales CFM/MPC(CSIC-UPV/EHU), P. Manuel de Lardizabal 5, 20018 San Sebastián (Spain); Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastián (Spain); Departamento de Física de Materiales, Facultad de Químicas, Universidad del País Vasco (UPV/EHU), Apartado 1072, 20080 San Sebastián (Spain); Alducin, Maite [Centro de Física de Materiales CFM/MPC(CSIC-UPV/EHU), P. Manuel de Lardizabal 5, 20018 San Sebastián (Spain); Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastián (Spain); Guo, Hua [Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2016-07-28

    The dissociative chemisorption of methane on metal surfaces has attracted much attention in recent years as a prototype of gas-surface reactions in understanding the mode specific and bond selective chemistry. In this work, we systematically investigate the influence of electron-hole pair excitations on the dissociative chemisorption of CH{sub 4}/CH{sub 3}D/CHD{sub 3} on Ni(111). The energy dissipation induced by surface electron-hole pair excitations is modeled as a friction force introduced in the generalized Langevin equation, in which the independent atomic friction coefficients are determined within the local-density friction approximation. Quasi-classical trajectory calculations for CH{sub 4}/CH{sub 3}D/CHD{sub 3} have been carried out on a recently developed twelve-dimensional potential energy surface. Comparing the dissociation probabilities obtained with and without friction, our results clearly indicate that the electron-hole pair effects are generally small, both on absolute reactivity of each vibrational state and on the mode specificity and bond selectivity. Given similar observations in both water and methane dissociation processes, we conclude that electron-hole pair excitations would not play an important role as long as the reaction is direct and the interaction time between the molecule and metal electrons is relatively short.

  4. Electrodynamics at the highest energies

    International Nuclear Information System (INIS)

    Klein, Spencer R.

    2002-01-01

    At very high energies, the bremsstrahlung and pair production cross sections exhibit complex behavior due to the material in which the interactions occur. The cross sections in dense media can be dramatically different than for isolated atoms. This writeup discusses these in-medium effects, emphasizing how the cross section has different energy and target density dependencies in different regimes. Data from SLAC experiment E-146 will be presented to confirm the energy and density scaling. Finally, QCD analogs of the electrodynamics effects will be discussed

  5. Level Densities and Radiative Strength Functions in 56FE and 57FE

    Energy Technology Data Exchange (ETDEWEB)

    Tavukcu, Emel [North Carolina State Univ., Raleigh, NC (United States)

    2002-12-10

    Understanding nuclear level densities and radiative strength functions is important for pure and applied nuclear physics. Recently, the Oslo Cyclotron Group has developed an experimental method to extract level densities and radiative strength functions simultaneously from the primary γ rays after a light-ion reaction. A primary γ-ray spectrum represents the γ-decay probability distribution. The Oslo method is based on the Axel-Brink hypothesis, according to which the primary γ-ray spectrum is proportional to the product of the level density at the final energy and the radiative strength function. The level density and the radiative strength function are fit to the experimental primary γ-ray spectra, and then normalized to known data. The method works well for heavy nuclei. The present measurements extend the Oslo method to the lighter mass nuclei 56Fe and 57Fe. The experimental level densities in 56Fe and 57Fe reveal step structure. This step structure is a signature for nucleon pair breaking. The predicted pairing gap parameter is in good agreement with the step corresponding to the first pair breaking. Thermodynamic quantities for 56Fe and 57Fe are derived within the microcanonical and canonical ensembles using the experimental level densities. Energy-temperature relations are considered using caloric curves and probability density functions. The differences between the thermodynamics of small and large systems are emphasized. The experimental heat capacities are compared with the recent theoretical calculations obtained in the Shell Model Monte Carlo method. Radiative strength functions in 56Fe and 57Fe have surprisingly high values at low γ-ray energies. This behavior has not been observed for heavy nuclei, but has been observed in other light- and medium-mass nuclei. The origin of this low γ-ray energy effect remains unknown.

  6. Local breast density assessment using reacquired mammographic images.

    Science.gov (United States)

    García, Eloy; Diaz, Oliver; Martí, Robert; Diez, Yago; Gubern-Mérida, Albert; Sentís, Melcior; Martí, Joan; Oliver, Arnau

    2017-08-01

    The aim of this paper is to evaluate the spatial glandular volumetric tissue distribution as well as the density measures provided by Volpara™ using a dataset composed of repeated pairs of mammograms, where each pair was acquired in a short time frame and in a slightly changed position of the breast. We conducted a retrospective analysis of 99 pairs of repeatedly acquired full-field digital mammograms from 99 different patients. The commercial software Volpara™ Density Maps (Volpara Solutions, Wellington, New Zealand) is used to estimate both the global and the local glandular tissue distribution in each image. The global measures provided by Volpara™, such as breast volume, volume of glandular tissue, and volumetric breast density are compared between the two acquisitions. The evaluation of the local glandular information is performed using histogram similarity metrics, such as intersection and correlation, and local measures, such as statistics from the difference image and local gradient correlation measures. Global measures showed a high correlation (breast volume R=0.99, volume of glandular tissue R=0.94, and volumetric breast density R=0.96) regardless the anode/filter material. Similarly, histogram intersection and correlation metric showed that, for each pair, the images share a high degree of information. Regarding the local distribution of glandular tissue, small changes in the angle of view do not yield significant differences in the glandular pattern, whilst changes in the breast thickness between both acquisition affect the spatial parenchymal distribution. This study indicates that Volpara™ Density Maps is reliable in estimating the local glandular tissue distribution and can be used for its assessment and follow-up. Volpara™ Density Maps is robust to small variations of the acquisition angle and to the beam energy, although divergences arise due to different breast compression conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Low Density Symmetry Energy Effects and the Neutron Star Crust Properties

    International Nuclear Information System (INIS)

    Kubis, S.; Alvarez-Castillo, D.E.; Porebska, J.

    2010-01-01

    The form of the nuclear symmetry energy E s around saturation point density leads to a different crust-core transition point in the neutron star and affects the crust properties. We show that the knowledge of E s close to the saturation point is not sufficient to determine the position of the transition point and the very low density behaviour is required. We also claim that crust properties are strongly influenced by the very high density behaviour of E s , so in order to conclude about the form of low density part of the symmetry energy from astrophysical data one must isolate properly the high density part. (authors)

  8. Energy-dense fast food products cost less: an observational study of the energy density and energy cost of Australian fast foods.

    Science.gov (United States)

    Wellard, Lyndal; Havill, Michelle; Hughes, Clare; Watson, Wendy L; Chapman, Kathy

    2015-12-01

    To examine the association between energy cost and energy density of fast food products. Twenty Sydney outlets of the five largest fast food chains were surveyed four times. Price and kilojoule data were collected for all limited-time-only menu items (n=54) and a sample of standard items (n=67). Energy cost ($/kilojoule) and energy density (kilojoules/gram) of menu items were calculated. There was a significant inverse relationship between menu item energy density and energy cost (pFast food chains could provide a wider range of affordable, lower-energy foods, use proportional pricing of larger serve sizes, or change defaults in meals to healthier options. More research is required to determine the most effective strategy to reduce the negative impact of fast food on the population's diet. Current pricing in the fast food environment may encourage unhealthier purchases. © 2015 Public Health Association of Australia.

  9. Internal wave energy flux from density perturbations in nonlinear stratifications

    Science.gov (United States)

    Lee, Frank M.; Allshouse, Michael R.; Swinney, Harry L.; Morrison, P. J.

    2017-11-01

    Tidal flow over the topography at the bottom of the ocean, whose density varies with depth, generates internal gravity waves that have a significant impact on the energy budget of the ocean. Thus, understanding the energy flux (J = p v) is important, but it is difficult to measure simultaneously the pressure and velocity perturbation fields, p and v . In a previous work, a Green's-function-based method was developed to calculate the instantaneous p, v , and thus J , given a density perturbation field for a constant buoyancy frequency N. Here we extend the previous analytic Green's function work to include nonuniform N profiles, namely the tanh-shaped and linear cases, because background density stratifications that occur in the ocean and some experiments are nonlinear. In addition, we present a finite-difference method for the general case where N has an arbitrary profile. Each method is validated against numerical simulations. The methods we present can be applied to measured density perturbation data by using our MATLAB graphical user interface EnergyFlux. PJM was supported by the U.S. Department of Energy Contract DE-FG05-80ET-53088. HLS and MRA were supported by ONR Grant No. N000141110701.

  10. Cellular automaton simulation of counter flow with paired pedestrians

    Directory of Open Access Journals (Sweden)

    Hui Xiong

    2011-12-01

    Full Text Available Knowledge on pedestrian behavior is the basis to build decision support system for crowd evacuation management in emergency. In this paper, the impact of paired walking behavior on pedestrian counter flow in a channel is studied. The pedestrian walking behaviors are simulated by the cellular automaton model and the pedestrians are classified as single right walker, single left walker, paired right walker, and paired left walker. Single walker can move forward, leftward, rightward or stand still. The paired pedestrians are considered as a combined unit similar to the single walker in terms of route choice and they can move to the same direction simultaneously. It is found that flow and velocity decrease with increase of the paired rate in case of stable density. Simulation results reveal the phase transitions in terms of density from free flow to the unstable flow and from the unstable flow to the congestion flow. However, the critical densities of phase transition are unaffected by the channel size.

  11. Photoproduction of lepton pairs in proton-nucleus and nucleus-nucleus collisions at RHIC and LHC energies

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, B. D.; Goncalves, V. P.; De Santana Amaral, J. T. [Universidade Federal de Pelotas, Instituto de Fisica e Matematica (Brazil)

    2013-03-25

    In this contribution we study coherent interactions as a probe of the nonlinear effects in the Quantum Electrodynamics (QED). In particular, we study the multiphoton effects in the production of leptons pairs for proton-nucleus and nucleus-nucleus collisions for heavy nuclei. In the proton-nucleus we assume the ultrarelativistic proton as a source of photons and estimate the photoproduction of lepton pairs on nuclei at RHIC and LHC energies considering the multiphoton effects associated to multiple rescattering of the projectile photon on the proton of the nucleus. In nucleus - nucleus colllisions we consider the two nuclei as a source of photons. As each scattering contributes with a factor {alpha}Z to the cross section, this contribution must be taken into account for heavy nuclei. We consider the Coulomb corrections to calculate themultiple scatterings and estimate the total cross section for muon and tau pair production in proton-nucleus and nucleus-nucleus collisions at RHIC and LHC energies.

  12. Knot soliton in DNA and geometric structure of its free-energy density.

    Science.gov (United States)

    Wang, Ying; Shi, Xuguang

    2018-03-01

    In general, the geometric structure of DNA is characterized using an elastic rod model. The Landau model provides us a new theory to study the geometric structure of DNA. By using the decomposition of the arc unit in the helical axis of DNA, we find that the free-energy density of DNA is similar to the free-energy density of a two-condensate superconductor. By using the φ-mapping topological current theory, the torus knot soliton hidden in DNA is demonstrated. We show the relation between the geometric structure and free-energy density of DNA and the Frenet equations in differential geometry theory are considered. Therefore, the free-energy density of DNA can be expressed by the curvature and torsion of the helical axis.

  13. High-energy-density physics foundation of inertial fusion and experimental astrophysics

    CERN Document Server

    Drake, R Paul

    2018-01-01

    The raw numbers of high-energy-density physics are amazing: shock waves at hundreds of km/s (approaching a million km per hour), temperatures of millions of degrees, and pressures that exceed 100 million atmospheres. This title surveys the production of high-energy-density conditions, the fundamental plasma and hydrodynamic models that can describe them and the problem of scaling from the laboratory to the cosmos. Connections to astrophysics are discussed throughout. The book is intended to support coursework in high-energy-density physics, to meet the needs of new researchers in this field, and also to serve as a useful reference on the fundamentals. Specifically the book has been designed to enable academics in physics, astrophysics, applied physics and engineering departments to provide in a single-course, an introduction to fluid mechanics and radiative transfer, with dramatic applications in the field of high-energy-density systems. This second edition includes pedagogic improvements to the presentation ...

  14. Nanocomposites with increased energy density through high aspect ratio PZT nanowires.

    Science.gov (United States)

    Tang, Haixiong; Lin, Yirong; Andrews, Clark; Sodano, Henry A

    2011-01-07

    High energy storage plays an important role in the modern electric industry. Herein, we investigated the role of filler aspect ratio in nanocomposites for energy storage. Nanocomposites were synthesized using lead zirconate titanate (PZT) with two different aspect ratio (nanowires, nanorods) fillers at various volume fractions dispersed in a polyvinylidene fluoride (PVDF) matrix. The permittivity constants of composites containing nanowires (NWs) were higher than those with nanorods (NRs) at the same inclusion volume fraction. It was also indicated that the high frequency loss tangent of samples with PZT nanowires was smaller than for those with nanorods, demonstrating the high electrical energy storage efficiency of the PZT NW nanocomposite. The high aspect ratio PZT NWs showed a 77.8% increase in energy density over the lower aspect ratio PZT NRs, under an electric field of 15 kV mm(-1) and 50% volume fraction. The breakdown strength was found to decrease with the increasing volume fraction of PZT NWs, but to only change slightly from a volume fraction of around 20%-50%. The maximum calculated energy density of nanocomposites is as high as 1.158 J cm(-3) at 50% PZT NWs in PVDF. Since the breakdown strength is lower compared to a PVDF copolymer such as poly(vinylidene fluoride-tertrifluoroethylene-terchlorotrifluoroethylene) P(VDF-TreEE-CTFE) and poly(vinylidene fluoride-co-hexafluoropropylene) P(VDF-HFP), the energy density of the nanocomposite could be significantly increased through the use of PZT NWs and a polymer with greater breakdown strength. These results indicate that higher aspect ratio fillers show promising potential to improve the energy density of nanocomposites, leading to the development of advanced capacitors with high energy density.

  15. Towards improved local hybrid functionals by calibration of exchange-energy densities

    International Nuclear Information System (INIS)

    Arbuznikov, Alexei V.; Kaupp, Martin

    2014-01-01

    A new approach for the calibration of (semi-)local and exact exchange-energy densities in the context of local hybrid functionals is reported. The calibration functions are derived from only the electron density and its spatial derivatives, avoiding spatial derivatives of the exact-exchange energy density or other computationally unfavorable contributions. The calibration functions fulfill the seven more important out of nine known exact constraints. It is shown that calibration improves substantially the definition of a non-dynamical correlation energy term for generalized gradient approximation (GGA)-based local hybrids. Moreover, gauge artifacts in the potential-energy curves of noble-gas dimers may be corrected by calibration. The developed calibration functions are then evaluated for a large range of energy-related properties (atomization energies, reaction barriers, ionization potentials, electron affinities, and total atomic energies) of three sets of local hybrids, using a simple one-parameter local-mixing. The functionals are based on (a) local spin-density approximation (LSDA) or (b) Perdew-Burke-Ernzerhof (PBE) exchange and correlation, and on (c) Becke-88 (B88) exchange and Lee-Yang-Parr (LYP) correlation. While the uncalibrated GGA-based functionals usually provide very poor thermochemical data, calibration allows a dramatic improvement, accompanied by only a small deterioration of reaction barriers. In particular, an optimized BLYP-based local-hybrid functional has been found that is a substantial improvement over the underlying global hybrids, as well as over previously reported LSDA-based local hybrids. It is expected that the present calibration approach will pave the way towards new generations of more accurate hyper-GGA functionals based on a local mixing of exchange-energy densities

  16. KIDS Nuclear Energy Density Functional: 1st Application in Nuclei

    Science.gov (United States)

    Gil, Hana; Papakonstantinou, Panagiota; Hyun, Chang Ho; Oh, Yongseok

    We apply the KIDS (Korea: IBS-Daegu-Sungkyunkwan) nuclear energy density functional model, which is based on the Fermi momentum expansion, to the study of properties of lj-closed nuclei. The parameters of the model are determined by the nuclear properties at the saturation density and theoretical calculations on pure neutron matter. For applying the model to the study of nuclei, we rely on the Skyrme force model, where the Skyrme force parameters are determined through the KIDS energy density functional. Solving Hartree-Fock equations, we obtain the energies per particle and charge radii of closed magic nuclei, namely, 16O, 28O, 40Ca, 48Ca, 60Ca, 90Zr, 132Sn, and 208Pb. The results are compared with the observed data and further improvement of the model is shortly mentioned.

  17. High Energy Density Sciences with High Power Lasers at SACLA

    Science.gov (United States)

    Kodama, Ryosuke

    2013-10-01

    One of the interesting topics on high energy density sciences with high power lasers is creation of extremely high pressures in material. The pressures of more than 0.1 TPa are the energy density corresponding to the chemical bonding energy, resulting in expectation of dramatic changes in the chemical reactions. At pressures of more than TPa, most of material would be melted on the shock Hugoniot curve. However, if the temperature is less than 1eV or lower than a melting point at pressures of more than TPa, novel solid states of matter must be created through a pressured phase transition. One of the interesting materials must be carbon. At pressures of more than TPa, the diamond structure changes to BC and cubic at more than 3TPa. To create such novel states of matter, several kinds of isentropic-like compression techniques are being developed with high power lasers. To explore the ``Tera-Pascal Science,'' now we have a new tool which is an x-ray free electron laser as well as high power lasers. The XFEL will clear the details of the HED states and also efficiently create hot dense matter. We have started a new project on high energy density sciences using an XFEL (SACLA) in Japan, which is a HERMES (High Energy density Revolution of Matter in Extreme States) project.

  18. TEMPO-based catholyte for high-energy density nonaqueous redox flow batteries.

    Science.gov (United States)

    Wei, Xiaoliang; Xu, Wu; Vijayakumar, Murugesan; Cosimbescu, Lelia; Liu, Tianbiao; Sprenkle, Vincent; Wang, Wei

    2014-12-03

    A TEMPO-based non-aqueous electrolyte with the TEMPO concentration as high as 2.0 m is demonstrated as a high-energy-density catholyte for redox flow battery applications. With a hybrid anode, Li|TEMPO flow cells using this electrolyte deliver an energy efficiency of ca. 70% and an impressively high energy density of 126 W h L(-1) . © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery.

    Science.gov (United States)

    Li, Bin; Nie, Zimin; Vijayakumar, M; Li, Guosheng; Liu, Jun; Sprenkle, Vincent; Wang, Wei

    2015-02-24

    Redox flow batteries are receiving wide attention for electrochemical energy storage due to their unique architecture and advantages, but progress has so far been limited by their low energy density (~25 Wh l(-1)). Here we report a high-energy density aqueous zinc-polyiodide flow battery. Using the highly soluble iodide/triiodide redox couple, a discharge energy density of 167 Wh l(-1) is demonstrated with a near-neutral 5.0 M ZnI2 electrolyte. Nuclear magnetic resonance study and density functional theory-based simulation along with flow test data indicate that the addition of an alcohol (ethanol) induces ligand formation between oxygen on the hydroxyl group and the zinc ions, which expands the stable electrolyte temperature window to from -20 to 50 °C, while ameliorating the zinc dendrite. With the high-energy density and its benign nature free from strong acids and corrosive components, zinc-polyiodide flow battery is a promising candidate for various energy storage applications.

  20. High Energy Density Dielectrics for Pulsed Power Applications

    National Research Council Canada - National Science Library

    Wu, Richard L; Bray, Kevin R

    2008-01-01

    This report was developed under a SBIR contract. Aluminum oxynitride (AlON) capacitors exhibit several promising characteristics for high energy density capacitor applications in extreme environments...

  1. Application of a Laplace transform pair model for high-energy x-ray spectral reconstruction.

    Science.gov (United States)

    Archer, B R; Almond, P R; Wagner, L K

    1985-01-01

    A Laplace transform pair model, previously shown to accurately reconstruct x-ray spectra at diagnostic energies, has been applied to megavoltage energy beams. The inverse Laplace transforms of 2-, 6-, and 25-MV attenuation curves were evaluated to determine the energy spectra of these beams. The 2-MV data indicate that the model can reliably reconstruct spectra in the low megavoltage range. Experimental limitations in acquiring the 6-MV transmission data demonstrate the sensitivity of the model to systematic experimental error. The 25-MV data result in a physically realistic approximation of the present spectrum.

  2. Revisiting the density scaling of the non-interacting kinetic energy.

    Science.gov (United States)

    Borgoo, Alex; Teale, Andrew M; Tozer, David J

    2014-07-28

    Scaling relations play an important role in the understanding and development of approximate functionals in density functional theory. Recently, a number of these relationships have been redefined in terms of the Kohn-Sham orbitals [Calderín, Phys. Rev. A: At., Mol., Opt. Phys., 2013, 86, 032510]. For density scaling the author proposed a procedure involving a multiplicative scaling of the Kohn-Sham orbitals whilst keeping their occupation numbers fixed. In the present work, the differences between this scaling with fixed occupation numbers and that of previous studies, where the particle number change implied by the scaling was accommodated through the use of the grand canonical ensemble, are examined. We introduce the terms orbital and ensemble density scaling for these approaches, respectively. The natural ambiguity of the density scaling of the non-interacting kinetic energy functional is examined and the ancillary definitions implicit in each approach are highlighted and compared. As a consequence of these differences, Calderín recovered a homogeneity of degree 1 for the non-interacting kinetic energy functional under orbital scaling, contrasting recent work by the present authors [J. Chem. Phys., 2012, 136, 034101] where the functional was found to be inhomogeneous under ensemble density scaling. Furthermore, we show that the orbital scaling result follows directly from the linearity and the single-particle nature of the kinetic energy operator. The inhomogeneity of the non-interacting kinetic energy functional under ensemble density scaling can be quantified by defining an effective homogeneity. This quantity is shown to recover the homogeneity values for important approximate forms that are exact for limiting cases such as the uniform electron gas and one-electron systems. We argue that the ensemble density scaling provides more insight into the development of new functional forms.

  3. Excitation energy and angular momentum dependence of the nuclear level densities

    International Nuclear Information System (INIS)

    Razavi, R.; Kakavand, T.; Behkami, A. N.

    2007-01-01

    We have investigated the excitation energy (E) dependence of nuclear level density for Bethe formula and constant temperature model. The level density parameter aa nd the back shifted energy from the Bethe formula are obtained by fitting the complete level schemes. Also the level density parameters from the constant temperature model have been determined for several nuclei. we have shown that the microscopic theory provides more precise information on the nuclear level densities. On the other hand, the spin cut-off parameter and effective moment of inertia are determined by studying of the angular momentum (J) dependence of the nuclear level density, and effective moment of inertia is compared with rigid body value.

  4. A pair natural orbital based implementation of CCSD excitation energies within the framework of linear response theory

    Science.gov (United States)

    Frank, Marius S.; Hättig, Christof

    2018-04-01

    We present a pair natural orbital (PNO)-based implementation of coupled cluster singles and doubles (CCSD) excitation energies that builds upon the previously proposed state-specific PNO approach to the excited state eigenvalue problem. We construct the excited state PNOs for each state separately in a truncated orbital specific virtual basis and use a local density-fitting approximation to achieve an at most quadratic scaling of the computational costs for the PNO construction. The earlier reported excited state PNO construction is generalized such that a smooth convergence of the results for charge transfer states is ensured for general coupled cluster methods. We investigate the accuracy of our implementation by applying it to a large and diverse test set comprising 153 singlet excitations in organic molecules. Already moderate PNO thresholds yield mean absolute errors below 0.01 eV. The performance of the implementation is investigated through the calculations on alkene chains and reveals an at most cubic cost-scaling for the CCSD iterations with the system size.

  5. Thermodynamic mechanism of density anomaly of liquid water

    Directory of Open Access Journals (Sweden)

    Makoto eYasutomi

    2015-03-01

    Full Text Available Although density anomaly of liquid water has long been studied by many different authors up to now, it is not still cleared what thermodynamic mechanism induces the anomaly. The thermodynamic properties of substances are determined by interparticle interactions. We analyze what characteristics of pair potential cause the density anomaly on the basis of statistical mechanics and thermodynamics using a thermodynamically self-consistent Ornstein-Zernike approximation (SCOZA. We consider a fluid of spherical particles with a pair potential given by a hard-core repulsion plus a soft-repulsion and an attraction. We show that the density anomaly occurs when the value of the soft-repulsive potential at hard-core contact is in some proper range, and the range depends on the attraction. Further, we show that the behavior of the excess internal energy plays an essential role in the density anomaly and the behavior is mainly determined by the values of the soft-repulsive potential, especially near the hard core contact. Our results show that most of ideas put forward up to now are not the direct causes of the density anomaly of liquid water.

  6. Hot accretion disks with electron-positron pairs

    International Nuclear Information System (INIS)

    White, T.R.; Lightman, A.P.

    1989-01-01

    The hot thermal accretion disks of the 1970s are studied and consideration is given to the effects of electron-positron pairs, which were originally neglected. It is found that disks cooled by internally produced photons have a critical accretion rate above which equilibrium is not possible in a radial annulus centered around r = 10 GM/c-squared, where M is the mass of the central object. This confirms and extends previous work by Kusunose and Takahara. Above the critical rate, pairs are created more rapidly than they can be destroyed. Below the critical rate, there are two solutions to the disk structure, one with a high pair density and one with a low pair density. Depending on the strength of the viscosity, the critical accretion rate corresponds to a critical luminosity of about 3-10 percent of the Eddington limit. 32 refs

  7. Analytic energy derivatives for the calculation of the first-order molecular properties using the domain-based local pair-natural orbital coupled-cluster theory

    Science.gov (United States)

    Datta, Dipayan; Kossmann, Simone; Neese, Frank

    2016-09-01

    The domain-based local pair-natural orbital coupled-cluster (DLPNO-CC) theory has recently emerged as an efficient and powerful quantum-chemical method for the calculation of energies of molecules comprised of several hundred atoms. It has been demonstrated that the DLPNO-CC approach attains the accuracy of a standard canonical coupled-cluster calculation to about 99.9% of the basis set correlation energy while realizing linear scaling of the computational cost with respect to system size. This is achieved by combining (a) localized occupied orbitals, (b) large virtual orbital correlation domains spanned by the projected atomic orbitals (PAOs), and (c) compaction of the virtual space through a truncated pair natural orbital (PNO) basis. In this paper, we report on the implementation of an analytic scheme for the calculation of the first derivatives of the DLPNO-CC energy for basis set independent perturbations within the singles and doubles approximation (DLPNO-CCSD) for closed-shell molecules. Perturbation-independent one-particle density matrices have been implemented in order to account for the response of the CC wave function to the external perturbation. Orbital-relaxation effects due to external perturbation are not taken into account in the current implementation. We investigate in detail the dependence of the computed first-order electrical properties (e.g., dipole moment) on the three major truncation parameters used in a DLPNO-CC calculation, namely, the natural orbital occupation number cutoff used for the construction of the PNOs, the weak electron-pair cutoff, and the domain size cutoff. No additional truncation parameter has been introduced for property calculation. We present benchmark calculations on dipole moments for a set of 10 molecules consisting of 20-40 atoms. We demonstrate that 98%-99% accuracy relative to the canonical CCSD results can be consistently achieved in these calculations. However, this comes with the price of tightening the

  8. Quantifying intermolecular interactions of ionic liquids using cohesive energy densities

    Science.gov (United States)

    2017-01-01

    For ionic liquids (ILs), both the large number of possible cation + anion combinations and their ionic nature provide a unique challenge for understanding intermolecular interactions. Cohesive energy density, ced, is used to quantify the strength of intermolecular interactions for molecular liquids, and is determined using the enthalpy of vaporization. A critical analysis of the experimental challenges and data to obtain ced for ILs is provided. For ILs there are two methods to judge the strength of intermolecular interactions, due to the presence of multiple constituents in the vapour phase of ILs. Firstly, cedIP, where the ionic vapour constituent is neutral ion pairs, the major constituent of the IL vapour. Secondly, cedC+A, where the ionic vapour constituents are isolated ions. A cedIP dataset is presented for 64 ILs. For the first time an experimental cedC+A, a measure of the strength of the total intermolecular interaction for an IL, is presented. cedC+A is significantly larger for ILs than ced for most molecular liquids, reflecting the need to break all of the relatively strong electrostatic interactions present in ILs. However, the van der Waals interactions contribute significantly to IL volatility due to the very strong electrostatic interaction in the neutral ion pair ionic vapour. An excellent linear correlation is found between cedIP and the inverse of the molecular volume. A good linear correlation is found between IL cedIP and IL Gordon parameter (which are dependent primarily on surface tension). ced values obtained through indirect methods gave similar magnitude values to cedIP. These findings show that cedIP is very important for understanding IL intermolecular interactions, in spite of cedIP not being a measure of the total intermolecular interactions of an IL. In the outlook section, remaining challenges for understanding IL intermolecular interactions are outlined. PMID:29308254

  9. Quantifying intermolecular interactions of ionic liquids using cohesive energy densities.

    Science.gov (United States)

    Lovelock, Kevin R J

    2017-12-01

    For ionic liquids (ILs), both the large number of possible cation + anion combinations and their ionic nature provide a unique challenge for understanding intermolecular interactions. Cohesive energy density, ced , is used to quantify the strength of intermolecular interactions for molecular liquids, and is determined using the enthalpy of vaporization. A critical analysis of the experimental challenges and data to obtain ced for ILs is provided. For ILs there are two methods to judge the strength of intermolecular interactions, due to the presence of multiple constituents in the vapour phase of ILs. Firstly, ced IP , where the ionic vapour constituent is neutral ion pairs, the major constituent of the IL vapour. Secondly, ced C+A , where the ionic vapour constituents are isolated ions. A ced IP dataset is presented for 64 ILs. For the first time an experimental ced C+A , a measure of the strength of the total intermolecular interaction for an IL, is presented. ced C+A is significantly larger for ILs than ced for most molecular liquids, reflecting the need to break all of the relatively strong electrostatic interactions present in ILs. However, the van der Waals interactions contribute significantly to IL volatility due to the very strong electrostatic interaction in the neutral ion pair ionic vapour. An excellent linear correlation is found between ced IP and the inverse of the molecular volume. A good linear correlation is found between IL ced IP and IL Gordon parameter (which are dependent primarily on surface tension). ced values obtained through indirect methods gave similar magnitude values to ced IP . These findings show that ced IP is very important for understanding IL intermolecular interactions, in spite of ced IP not being a measure of the total intermolecular interactions of an IL. In the outlook section, remaining challenges for understanding IL intermolecular interactions are outlined.

  10. An Electrochemical Capacitor with Applicable Energy Density of 7.4 Wh/kg at Average Power Density of 3000 W/kg.

    Science.gov (United States)

    Zhai, Teng; Lu, Xihong; Wang, Hanyu; Wang, Gongming; Mathis, Tyler; Liu, Tianyu; Li, Cheng; Tong, Yexiang; Li, Yat

    2015-05-13

    Electrochemical capacitors represent a new class of charge storage devices that can simultaneously achieve high energy density and high power density. Previous reports have been primarily focused on the development of high performance capacitor electrodes. Although these electrodes have achieved excellent specific capacitance based on per unit mass of active materials, the gravimetric energy densities calculated based on the weight of entire capacitor device were fairly small. This is mainly due to the large mass ratio between current collector and active material. We aimed to address this issue by a 2-fold approach of minimizing the mass of current collector and increasing the electrode performance. Here we report an electrochemical capacitor using 3D graphene hollow structure as current collector, vanadium sulfide and manganese oxide as anode and cathode materials, respectively. 3D graphene hollow structure provides a lightweight and highly conductive scaffold for deposition of pseudocapacitive materials. The device achieves an excellent active material ratio of 24%. Significantly, it delivers a remarkable energy density of 7.4 Wh/kg (based on the weight of entire device) at the average power density of 3000 W/kg. This is the highest gravimetric energy density reported for asymmetric electrochemical capacitors at such a high power density.

  11. Lithium-Based High Energy Density Flow Batteries

    Science.gov (United States)

    Bugga, Ratnakumar V. (Inventor); West, William C. (Inventor); Kindler, Andrew (Inventor); Smart, Marshall C. (Inventor)

    2014-01-01

    Systems and methods in accordance with embodiments of the invention implement a lithium-based high energy density flow battery. In one embodiment, a lithium-based high energy density flow battery includes a first anodic conductive solution that includes a lithium polyaromatic hydrocarbon complex dissolved in a solvent, a second cathodic conductive solution that includes a cathodic complex dissolved in a solvent, a solid lithium ion conductor disposed so as to separate the first solution from the second solution, such that the first conductive solution, the second conductive solution, and the solid lithium ionic conductor define a circuit, where when the circuit is closed, lithium from the lithium polyaromatic hydrocarbon complex in the first conductive solution dissociates from the lithium polyaromatic hydrocarbon complex, migrates through the solid lithium ionic conductor, and associates with the cathodic complex of the second conductive solution, and a current is generated.

  12. Dependence of two-proton radioactivity on nuclear pairing models

    Science.gov (United States)

    Oishi, Tomohiro; Kortelainen, Markus; Pastore, Alessandro

    2017-10-01

    Sensitivity of two-proton emitting decay to nuclear pairing correlation is discussed within a time-dependent three-body model. We focus on the 6Be nucleus assuming α +p +p configuration, and its decay process is described as a time evolution of the three-body resonance state. For a proton-proton subsystem, a schematic density-dependent contact (SDDC) pairing model is employed. From the time-dependent calculation, we observed the exponential decay rule of a two-proton emission. It is shown that the density dependence does not play a major role in determining the decay width, which can be controlled only by the asymptotic strength of the pairing interaction. This asymptotic pairing sensitivity can be understood in terms of the dynamics of the wave function driven by the three-body Hamiltonian, by monitoring the time-dependent density distribution. With this simple SDDC pairing model, there remains an impossible trinity problem: it cannot simultaneously reproduce the empirical Q value, decay width, and the nucleon-nucleon scattering length. This problem suggests that a further sophistication of the theoretical pairing model is necessary, utilizing the two-proton radioactivity data as the reference quantities.

  13. Physics and applications of high energy density plasmas. Extreme state driven by pulsed electromagnetic energy

    International Nuclear Information System (INIS)

    Horioka, Kazuhiko

    2002-06-01

    The papers presented at the symposium on ''Physics and application of high energy density plasmas, held December 20-21, 2001 at NIFS'' are collected in this proceedings. The topics covered in the meeting include dense z-pinches, plasma focus, intense charged particle beams, intense radiation sources, discharge pumped X-ray lasers, their diagnostics, and applications of them. The papers reflect the present status and trends in the research field of high energy density plasmas. (author)

  14. Hydrate-melt electrolytes for high-energy-density aqueous batteries

    Science.gov (United States)

    Yamada, Yuki; Usui, Kenji; Sodeyama, Keitaro; Ko, Seongjae; Tateyama, Yoshitaka; Yamada, Atsuo

    2016-10-01

    Aqueous Li-ion batteries are attracting increasing attention because they are potentially low in cost, safe and environmentally friendly. However, their low energy density (water and the limited selection of suitable negative electrodes, is problematic for their future widespread application. Here, we explore optimized eutectic systems of several organic Li salts and show that a room-temperature hydrate melt of Li salts can be used as a stable aqueous electrolyte in which all water molecules participate in Li+ hydration shells while retaining fluidity. This hydrate-melt electrolyte enables a reversible reaction at a commercial Li4Ti5O12 negative electrode with a low reaction potential (1.55 V versus Li+/Li) and a high capacity (175 mAh g-1). The resultant aqueous Li-ion batteries with high energy density (>130 Wh kg-1) and high voltage (˜2.3-3.1 V) represent significant progress towards performance comparable to that of commercial non-aqueous batteries (with energy densities of ˜150-400 Wh kg-1 and voltages of ˜2.4-3.8 V).

  15. Workshop on extremely high energy density plasmas and their diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Shozo (ed.)

    2001-09-01

    Compiled are the papers presented at the workshop on 'Extremely High Energy Density Plasmas and Their Diagnostics' held at National Institute for Fusion Science. The papers cover physics and applications of extremely high-energy density plasmas such as dense z-pinch, plasma focus, and intense pulsed charged beams. Separate abstracts were presented for 7 of the papers in this report. The remaining 25 were considered outside the subject scope of INIS. (author)

  16. Workshop on extremely high energy density plasmas and their diagnostics

    International Nuclear Information System (INIS)

    Ishii, Shozo

    2001-09-01

    Compiled are the papers presented at the workshop on 'Extremely High Energy Density Plasmas and Their Diagnostics' held at National Institute for Fusion Science. The papers cover physics and applications of extremely high-energy density plasmas such as dense z-pinch, plasma focus, and intense pulsed charged beams. Separate abstracts were presented for 7 of the papers in this report. The remaining 25 were considered outside the subject scope of INIS. (author)

  17. Dietary Energy Density in the Australian Adult Population from National Nutrition Surveys 1995 to 2012.

    Science.gov (United States)

    Grech, Amanda Lee; Rangan, Anna; Allman-Farinelli, Margaret

    2017-12-01

    It is hypothesized that the observed proliferation of energy-dense, nutrient-poor foods globally is an important contributing factor to the development of the obesity epidemic. However, evidence that the population's dietary energy density has increased is sparse. The World Cancer Research Fund recommends that dietary energy density be density of the Australian population has changed between 1995 and 2012. A secondary analysis of two cross-sectional Australian national nutrition surveys from 1995 and 2011/2012 was conducted. Participants of the surveys included adults aged 18 years and older (1995 n=10,986 and 2011/2012 n=9,435) completing 24-hour dietary recalls, including a second recall for a subset of the population (10.4% in 1995 and 64.6% in 2011/2012). Outcome measures included the change in dietary energy density (calculated as energy/weight of food [kcal/g] for food only) between surveys. The National Cancer Institute method for "estimating ratios of two dietary components that are consumed nearly every day" was used to determine the usual distribution and the percentage of participants reporting energy density density was 1.59 (0.26) kcal/g and 1.64 (0.32) kcal/g (Pdensity recommendations. For those aged 70 years and older, the percentage with energy density density density has increased between the two surveys and few people consumed low energy-dense diets in line with recommendations. The change was largely due to increased energy density of older adult's diets, while young adults had high dietary energy density at both time points. These data suggest efforts now focus on the evaluation of the role of modifying energy density of the diet to reduce the risk of weight gain in adults. Copyright © 2017 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  18. Effects of energy content and energy density of pre-portioned entrées on energy intake

    OpenAIRE

    Blatt, Alexandria D.; Williams, Rachel A.; Roe, Liane S.; Rolls, Barbara J.

    2012-01-01

    Pre-portioned entrées are commonly consumed to help control portion size and limit energy intake. The influence of entrée characteristics on energy intake, however, has not been well studied. We determined how the effects of energy content and energy density (ED, kcal/g) of pre-portioned entrées combine to influence daily energy intake. In a crossover design, 68 non-dieting adults (28 men and 40 women) were provided with breakfast, lunch, and dinner on one day a week for four weeks. Each meal...

  19. Energies of the ground state and first excited 0 sup + state in an exactly solvable pairing model

    CERN Document Server

    Dinh Dang, N

    2003-01-01

    Several approximations are tested by calculating the ground-state energy and the energy of the first excited 0 sup + state using an exactly solvable model with two symmetric levels interacting via a pairing force. They are the BCS approximation (BCS), Lipkin-Nogami (LN) method, random-phase approximation (RPA), quasiparticle RPA (QRPA), the renormalized RPA (RRPA), and renormalized QRPA (RQRPA). It is shown that, in the strong-coupling regime, the QRPA which neglects the scattering term of the model Hamiltonian offers the best fit to the exact solutions. A recipe is proposed using the RRPA and RQRPA in combination with the pairing gap given by the LN method. Applying this recipe, it is shown that the superfluid-normal phase transition is avoided, and a reasonably good description for both of the ground-state energy and the energy of the first excited 0 sup + state is achieved. (orig.)

  20. Non-local energy density functionals: models plus some exact general results

    International Nuclear Information System (INIS)

    March, N.H.

    2001-02-01

    Holas and March (Phys. Rev. A51, 2040, 1995) gave a formally exact expression for the force - δV xc (r-tilde)/δr-tilde associated with the exchange-correlation potential V xc (r-tilde) of density functional theory. This forged a precise link between first- and second-order density matrices and V xc (r-tilde). Here models are presented in which these low-order matrices can be related to the ground-state electron density. This allows non-local energy density functionals to be constructed within the framework of such models. Finally, results emerging from these models have led to the derivation of some exact 'nuclear cusp' relations for exchange and correlation energy densities in molecules, clusters and condensed phases. (author)

  1. Kaon Condensation in Neutron Stars and High Density Behaviour of Nuclear Symmetry Energy

    International Nuclear Information System (INIS)

    Kubis, S.; Kutschera, M.

    1999-01-01

    We study the influence of a high density behaviour of the nuclear symmetry energy on a kaon condensation in neutron stars. We find that the symmetry energy typical for several realistic nuclear potentials, which decreases at high densities, inhibits kaon condensation for weaker kaon-nucleon couplings at any density. There exists a threshold coupling above which the kaon condensate forms at densities exceeding some critical value. This is in contrast to the case of rising symmetry energy, as e.g. for relativistic mean field models, when the kaon condensate can form for any coupling at a sufficiently high density. Properties of the condensate are also different in both cases. (author)

  2. Kaon Condensation in Neutron Stars and High Density Behaviour of Nuclear Symmetry Energy

    International Nuclear Information System (INIS)

    Kubis, S.; Kutschera, M.

    1999-04-01

    We study the influence of a high density behaviour of the nuclear symmetry energy on a kaon condensation in neutron stars. We find that the symmetry energy typical for several realistic nuclear potentials, which decreases at high densities, inhibits kaon condensation for weaker kaon-nucleon couplings at any density. There exists a threshold coupling above which the kaon condensate forms at densities exceeding some critical value. This is in contrast to the case of rising symmetry energy, as e.g. for relativistic mean field models, when the kaon condensate can form for any coupling at a sufficiently high density. Properties of the condensate are also different in both cases

  3. Color ferromagnetic vacuum states in QCD and two-loop energy densities

    International Nuclear Information System (INIS)

    Nielsen, H.B.; Ninomiya, M.

    1979-12-01

    Two-loop energy densities of color ferromagnetic states are obtained using the β-function calculated to two-loop approximation and the exact formula for the energy density of such a state. This is used to derive bounds on the MIT bag constant correcting the previous bound in one-loop approximation. For a constant field color ferromagnetic ansatz state the bound on the QCD scale parameter Λsub(p) 3 -vacuum ansatz with two-loop and instanton correction gives Λsub(p)<= 0.16 GeV. Tt is stressed that the 'perturbative vacuum', which is identified with the inside bag state is a somewhat ill defined concept due to a path-dependence in the integral giving the energy density. (Auth.)

  4. Systematics of nuclear mass and level density formulas

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hisashi [Fuji Electric Co. Ltd., Kawasaki, Kanagawa (Japan)

    1998-03-01

    The phenomenological models of the nuclear mass and level density are close related to each other, the nuclear ground and excited state properties are described by using the parameter systematics on the mass and level density formulas. The main aim of this work is to provide in an analytical framework the improved energy dependent shell, pairing and deformation corrections generalized to the collective enhancement factors, which offer a systematic prescription over a great number of nuclear reaction cross sections. The new formulas are shown to be in close agreement with not only the empirical nuclear mass data but the measured slow neutron resonance spacings, and experimental systematics observed in the excitation energy dependent properties. (author)

  5. Coherent and noncoherent double diffractive production of QQ-bar pairs in heavy-ion collisions at high energies

    International Nuclear Information System (INIS)

    Agababyan, N.M.; Chatrchyan, S.A.; Galoyan, A.S.; Malakhov, A.I.; Melkumov, G.L.; Zarubin, P.I.; Jenkovszky, L.L.

    1999-01-01

    The coherent and noncoherent double diffractive production of heavy quark-antiquark pairs in ion scattering at the LHC energies has been considered. The total and differential cross sections for such processes featuring the production of cc-bar and bb-bar quark pairs in pp, CaCa, and PbPb collisions have been estimated. It has been shown that the fraction of heavy quark-antiquark pairs produced in double diffractive scattering amounts to a few percent of the number of QQ-bar pairs produced in hard QCD scattering; therefore, it is necessary to take into account such processes in detecting heavy quarks, in seeking Higgs bosons of intermediate mass, in investigating the suppression of heavy quarkonia in quark-gluon plasma, and so on. It has been demonstrated that the cross section for coherent scattering is so large that this process can be used to study collective effects in nuclei at high energies. Large values of the quark-antiquark invariant mass, M QQ-bar > or approx. 100 GeV, in association with a large rapidity gap between diffractive jets, Δη>5, exemplify manifestations of such nuclear interactions

  6. Direct electron-pair production by high energy heavy charged particles

    Science.gov (United States)

    Takahashi, Y.; Gregory, J. C.; Hayashi, T.; Dong, B. L.

    1989-01-01

    Direct electron pain production via virtual photons by moving charged particles is a unique electro-magnetic process having a substantial dependence on energy. Most electro-magnetic processes, including transition radiation, cease to be sensitive to the incident energy above 10 TeV/AMU. Thus, it is expected, that upon establishment of cross section and detection efficiency of this process, it may provide a new energy measuring technique above 10 TeV/AMU. Three accelerator exposures of emulsion chambers designed for measurements of direct electron-pains were performed. The objectives of the investigation were to provide the fundamental cross-section data in emulsion stacks to find the best-fit theoretical model, and to provide a calibration of measurements of direct electron-pairs in emulsion chamber configurations. This paper reports the design of the emulsion chambers, accelerator experiments, microscope measurements, and related considerations for future improvements of the measurements, and for possible applications to high energy cosmic ray experiments. Also discussed are the results from scanning 56m of emulsion tracks at 1200x magnification so that scanning efficiency is optimized. Measurements of the delta-ray range spectrum were also performed for much shorter track lengths, but with sufficiently large statistics in the number of measured delta-rays.

  7. Energy density functional analysis of shape coexistence in 44S

    International Nuclear Information System (INIS)

    Li, Z. P.; Yao, J. M.; Vretenar, D.; Nikšić, T.; Meng, J.

    2012-01-01

    The structure of low-energy collective states in the neutron-rich nucleus 44 S is analyzed using a microscopic collective Hamiltonian model based on energy density functionals (EDFs). The calculated triaxial energy map, low-energy spectrum and corresponding probability distributions indicate a coexistence of prolate and oblate shapes in this nucleus.

  8. Physics and applications of high energy density plasmas. Extreme state driven by pulsed electromagnetic energy

    Energy Technology Data Exchange (ETDEWEB)

    Horioka, Kazuhiko (ed.)

    2002-06-01

    The papers presented at the symposium on ''Physics and application of high energy density plasmas, held December 20-21, 2001 at NIFS'' are collected in this proceedings. The topics covered in the meeting include dense z-pinches, plasma focus, intense charged particle beams, intense radiation sources, discharge pumped X-ray lasers, their diagnostics, and applications of them. The papers reflect the present status and trends in the research field of high energy density plasmas. (author)

  9. Postmortem validation of breast density using dual-energy mammography

    OpenAIRE

    Molloi, Sabee; Ducote, Justin L.; Ding, Huanjun; Feig, Stephen A.

    2014-01-01

    Purpose: Mammographic density has been shown to be an indicator of breast cancer risk and also reduces the sensitivity of screening mammography. Currently, there is no accepted standard for measuring breast density. Dual energy mammography has been proposed as a technique for accurate measurement of breast density. The purpose of this study is to validate its accuracy in postmortem breasts and compare it with other existing techniques. Methods: Forty postmortem breasts were imaged using a dua...

  10. Equation satisfied by electron-electron mutual Coulomb repulsion energy density functional

    OpenAIRE

    Joubert, Daniel P.

    2011-01-01

    The electron-electron mutual Coulomb repulsion energy density functional satisfies an equation that links functionals and functional derivatives at N-electron and (N-1)-electron densities for densities determined from the same adiabatic scaled external potential for the N-electron system.

  11. Cosmological constant problem and renormalized vacuum energy density in curved background

    Energy Technology Data Exchange (ETDEWEB)

    Kohri, Kazunori [Theory Center, IPNS, KEK, Tsukuba 305-0801, Ibaraki (Japan); Matsui, Hiroki, E-mail: kohri@post.kek.jp, E-mail: matshiro@post.kek.jp [The Graduate University of Advanced Studies (Sokendai), Tsukuba 305-0801, Ibaraki (Japan)

    2017-06-01

    The current vacuum energy density observed as dark energy ρ{sub dark}≅ 2.5×10{sup −47} GeV{sup 4} is unacceptably small compared with any other scales. Therefore, we encounter serious fine-tuning problem and theoretical difficulty to derive the dark energy. However, the theoretically attractive scenario has been proposed and discussed in literature: in terms of the renormalization-group (RG) running of the cosmological constant, the vacuum energy density can be expressed as ρ{sub vacuum}≅ m {sup 2} H {sup 2} where m is the mass of the scalar field and rather dynamical in curved spacetime. However, there has been no rigorous proof to derive this expression and there are some criticisms about the physical interpretation of the RG running cosmological constant. In the present paper, we revisit the RG running effects of the cosmological constant and investigate the renormalized vacuum energy density in curved spacetime. We demonstrate that the vacuum energy density described by ρ{sub vacuum}≅ m {sup 2} H {sup 2} appears as quantum effects of the curved background rather than the running effects of cosmological constant. Comparing to cosmological observational data, we obtain an upper bound on the mass of the scalar fields to be smaller than the Planck mass, m ∼< M {sub Pl}.

  12. Pairing and low temperature properties of 2 D Fermi-systems with attraction between particles

    International Nuclear Information System (INIS)

    Gorbar, E.V.; Gusynin, V.P.; Loktev, V.M.

    1992-01-01

    Proceeding from microscopic model Hamiltonian for the system of Fermi-particles with attraction the effective Lagrangian, admitting the analysis of its superconducting properties at arbitrary fermion concentration, is obtained.Exact solution for gap and chemical potential makes it possible to trace from local pair situation to Cooper pairing. The crucial parameter discriminating between the regions of exotic and normal superconducting behaviour is show to be that of the energy of the bound fermion state, which, however, rapidly disappears with fermion density increasing. The solutions of the equations for the case of finite temperatures are analysed. (author). 42 refs

  13. Triton-3He relative and differential flows and the high density behavior of nuclear symmetry

    International Nuclear Information System (INIS)

    Yong, Gaochan; Li, Baoan; Chen, Liewen

    2010-01-01

    Using a transport model coupled with a phase-space coalescence after-burner we study the triton- 3 He relative and differential transverse flows in semi-central 132 Sn + 124 Sn reactions at a beam energy of 400 MeV/nucleon. We find that the triton- 3 He pairs carry interesting information about the density dependence of the nuclear symmetry energy. The t- 3 He relative flow can be used as a particularly powerful probe of the high-density behavior of the nuclear symmetry energy. (author)

  14. Monte Carlo studies of thermalization of electron-hole pairs in spin-polarized degenerate electron gas in monolayer graphene

    Science.gov (United States)

    Borowik, Piotr; Thobel, Jean-Luc; Adamowicz, Leszek

    2018-02-01

    Monte Carlo method is applied to the study of relaxation of excited electron-hole (e-h) pairs in graphene. The presence of background of spin-polarized electrons, with high density imposing degeneracy conditions, is assumed. To such system, a number of e-h pairs with spin polarization parallel or antiparallel to the background is injected. Two stages of relaxation: thermalization and cooling are clearly distinguished when average particles energy and its standard deviation σ _E are examined. At the very beginning of thermalization phase, holes loose energy to electrons, and after this process is substantially completed, particle distributions reorganize to take a Fermi-Dirac shape. To describe the evolution of and σ _E during thermalization, we define characteristic times τ _ {th} and values at the end of thermalization E_ {th} and σ _ {th}. The dependence of these parameters on various conditions, such as temperature and background density, is presented. It is shown that among the considered parameters, only the standard deviation of electrons energy allows to distinguish between different cases of relative spin polarizations of background and excited electrons.

  15. Energy density, stopping and flow in ultrarelativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Sorge, H.; von Keitz, A.; Mattiello, R.; Stoecker, H.; Greiner, W.

    1990-01-01

    The Lorentz invariant molecular dynamics approach (RQMD) is employed to investigate the space-time evolution of heavy ion collisions at energies (E kin = 10AGeV hor-ellipsis 200AGeV). The calculations for various nucleus nucleus reactions show a high degree of stopping power. The importance of secondary rescattering at these beam energies is demonstrated. The computed nucleon rapidity distributions are compared to available experimental data. It is demonstrated that nonlinear, collective effects like full stopping of target and projectile and matter flow could be expected for heavy projectiles only. For nuclear collisions in the Booster era at BNL and for the lead beam at CERN SPS the authors predict a stimulating future: then a nearly equilibrated, long lived (8 fm/c) macroscopic volume of very high energy density (> 1 GeV/fm 3 ) and baryon density (> 5 times ground state density) is produced

  16. Building a universal nuclear energy density functional

    International Nuclear Information System (INIS)

    Bertsch, G F

    2007-01-01

    This talk describes a new project in SciDAC II in the area of low-energy nuclear physics. The motivation and goals of the SciDAC are presented as well as an outline of the theoretical and computational methodology that will be employed. An important motivation is to have more accurate and reliable predictions of nuclear properties including their binding energies and low-energy reaction rates. The theoretical basis is provided by density functional theory, which the only available theory that can be systematically applied to all nuclei. However, other methodologies based on wave function methods are needed to refine the functionals and to make applications to dynamic processes

  17. Path analysis of the energy density of wood in eucalyptus clones.

    Science.gov (United States)

    Couto, A M; Teodoro, P E; Trugilho, P F

    2017-03-16

    Path analysis has been used for establishing selection criteria in genetic breeding programs for several crops. However, it has not been used in eucalyptus breeding programs yet. In the present study, we aimed to identify the wood technology traits that could be used as the criteria for direct and indirect selection of eucalyptus genotypes with high energy density of wood. Twenty-four eucalyptus clones were evaluated in a completely randomized design with five replications. The following traits were assessed: basic wood density, total extractives, lignin content, ash content, nitrogen content, carbon content, hydrogen content, sulfur content, oxygen content, higher calorific power, holocellulose, and energy density. After verifying the variability of all evaluated traits among the clones, a two-dimensional correlation network was used to determine the phenotypic patterns among them. The obtained coefficient of determination (0.94) presented a higher magnitude in relation to the effect of the residual variable, and it served as an excellent model for explaining the genetic effects related to the variations observed in the energy density of wood in all eucalyptus clones. However, for future studies, we recommend evaluating other traits, especially the morphological traits, because of the greater ease in their measurement. Selecting clones with high basic density is the most promising strategy for eucalyptus breeding programs that aim to increase the energy density of wood because of its high heritability and magnitude of the cause-and-effect relationship with this trait.

  18. Connections between population density, energy use, and GHG emissions in water networks

    Energy Technology Data Exchange (ETDEWEB)

    Filion, Y.R. [Queen' s Univ., Kingston, ON (Canada). Dept. of Civil Engineering

    2007-07-01

    There is a growing concern that urban sprawl and highly dispersed urban infrastructure in cities is posing significant environmental impacts. However, there is no agreement on the suitability of interventions such as population intensification on reducing environmental impacts. This paper investigated the connection between population intensification and environmental impact in water distribution networks. Specifically, it examined the relationship between population density, annual per capita energy use, and annual per capita greenhouse gas (GHG) emissions in water distribution networks. It also examined which population densities produce low levels of annual per capita energy use and GHG emissions. An analytical model of a trunk main was developed to connect population density to energy use and GHG emissions. The model considered energy use in five life activities of the trunk main, namely pipe fabrication, pipe repair, water pumping, and pipe recycling and/or disposal. The energy use model was combined with emission factors and electricity fuel-source mixtures from four Canadian regions (Atlantic Provinces, Quebec, Ontario, and Alberta) to compute representative levels of annual per capita GHGs emitted by the trunk main. It was concluded that increasing population density from 10 ca/ha to 150 ca/ha reduced energy use and GHG emissions by 67per cent and that increasing population density beyond 150 ca/ha produces no significant decrease in annual per capita energy use and GHG emissions. Further analysis on looped networks is required to verify these preliminary findings. 10 refs., 3 tabs., 2 figs.

  19. Enhanced production of low-mass electron-positron pairs in 40-AGeV Pb-Au collisions at the CERN SPS.

    Science.gov (United States)

    Adamová, D; Agakichiev, G; Appelshäuser, H; Belaga, V; Braun-Munzinger, P; Cherlin, A; Damjanović, S; Dietel, T; Dietrich, L; Drees, A; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Z; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kushpil, V; Lenkeit, B; Maas, A; Marín, A; Milosević, J; Milov, A; Miśkowiec, D; Panebrattsev, Yu; Petchenova, O; Petrácek, V; Pfeiffer, A; Rak, J; Ravinovich, I; Rehak, P; Richter, M; Sako, H; Schmitz, W; Sedykh, S; Seipp, W; Sharma, A; Shimansky, S; Slívová, J; Specht, H J; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, I; Wessels, J P; Wienold, T; Windelband, B; Wurm, J P; Xie, W; Yurevich, S; Yurevich, V

    2003-07-25

    We report on first measurements of low-mass electron-positron pairs in Pb-Au collisions at the CERN SPS beam energy of 40 AGeV. The observed pair yield integrated over the range of invariant masses 0.2e(+)e(-) annihilation with a modified rho propagator. They may be linked to chiral symmetry restoration and support the notion that the in-medium modifications of the rho are more driven by baryon density than by temperature.

  20. Enhanced production of low-mass electron-positron pairs in 40-AGeV Pb-Au collisions at the CERN SPS

    CERN Document Server

    Adamova, D; Appelshäuser, H; Belaga, V; Braun-Munzinger, P; Cherlin, A; Damjanovic, S; Dietel, T; Dietrich, L; Drees, A; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Zeev; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kushpil, V; Lenkeit, B C; Maas, A; Marin, A; Milosevic, J; Milov, A; Miskowiec, D; Panebratsev, Yu A; Petchenova, O Yu; Petracek, V; Pfeiffer, A; Rak, J; Ravinovich, I; Rehak, P; Richter, M; Sako, H; Schmitz, W; Sedykh, S; Seipp, W; Sharma, A; Shimansky, S S; Slivova, J; Specht, H J; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, Itzhak; Wessels, J P; Wienold, T; Windelband, B; Wurm, J P; Xie, W; Yurevich, S; Yurevich, V I

    2003-01-01

    We report on first measurements of low-mass electron pairs in Pb-Au collisions at the lower SPS beam energy of 40 AGeV. The pair yield integrated over the range of invariant masses 0.2 e+ e- annihilation with a modified rho-propagator. They may be linked to chiral symmetry restoration and support the notion that the in-medium modifications of the rho are more driven by baryon density than by temperature.

  1. Highly Compressed Ion Beams for High Energy Density Science

    CERN Document Server

    Friedman, Alex; Briggs, Richard J; Callahan, Debra; Caporaso, George; Celata, C M; Davidson, Ronald C; Faltens, Andy; Grant-Logan, B; Grisham, Larry; Grote, D P; Henestroza, Enrique; Kaganovich, Igor D; Lee, Edward; Lee, Richard; Leitner, Matthaeus; Nelson, Scott D; Olson, Craig; Penn, Gregory; Reginato, Lou; Renk, Tim; Rose, David; Sessler, Andrew M; Staples, John W; Tabak, Max; Thoma, Carsten H; Waldron, William; Welch, Dale; Wurtele, Jonathan; Yu, Simon

    2005-01-01

    The Heavy Ion Fusion Virtual National Laboratory (HIF-VNL) is developing the intense ion beams needed to drive matter to the High Energy Density (HED) regimes required for Inertial Fusion Energy (IFE) and other applications. An interim goal is a facility for Warm Dense Matter (WDM) studies, wherein a target is heated volumetrically without being shocked, so that well-defined states of matter at 1 to 10 eV are generated within a diagnosable region. In the approach we are pursuing, low to medium mass ions with energies just above the Bragg peak are directed onto thin target "foils," which may in fact be foams or "steel wool" with mean densities 1% to 100% of solid. This approach complements that being pursued at GSI, wherein high-energy ion beams deposit a small fraction of their energy in a cylindrical target. We present the requirements for warm dense matter experiments, and describe suitable accelerator concepts, including novel broadband traveling wave pulse-line, drift-tube linac, RF, and single-gap approa...

  2. Incorporation of Hydrogen Bond Angle Dependency into the Generalized Solvation Free Energy Density Model.

    Science.gov (United States)

    Ma, Songling; Hwang, Sungbo; Lee, Sehan; Acree, William E; No, Kyoung Tai

    2018-04-23

    To describe the physically realistic solvation free energy surface of a molecule in a solvent, a generalized version of the solvation free energy density (G-SFED) calculation method has been developed. In the G-SFED model, the contribution from the hydrogen bond (HB) between a solute and a solvent to the solvation free energy was calculated as the product of the acidity of the donor and the basicity of the acceptor of an HB pair. The acidity and basicity parameters of a solute were derived using the summation of acidities and basicities of the respective acidic and basic functional groups of the solute, and that of the solvent was experimentally determined. Although the contribution of HBs to the solvation free energy could be evenly distributed to grid points on the surface of a molecule, the G-SFED model was still inadequate to describe the angle dependency of the HB of a solute with a polarizable continuum solvent. To overcome this shortcoming of the G-SFED model, the contribution of HBs was formulated using the geometric parameters of the grid points described in the HB coordinate system of the solute. We propose an HB angle dependency incorporated into the G-SFED model, i.e., the G-SFED-HB model, where the angular-dependent acidity and basicity densities are defined and parametrized with experimental data. The G-SFED-HB model was then applied to calculate the solvation free energies of organic molecules in water, various alcohols and ethers, and the log P values of diverse organic molecules, including peptides and a protein. Both the G-SFED model and the G-SFED-HB model reproduced the experimental solvation free energies with similar accuracy, whereas the distributions of the SFED on the molecular surface calculated by the G-SFED and G-SFED-HB models were quite different, especially for molecules having HB donors or acceptors. Since the angle dependency of HBs was included in the G-SFED-HB model, the SFED distribution of the G-SFED-HB model is well described

  3. Energy density of a dissipative polarizable solid by a Lagrangean formalism

    International Nuclear Information System (INIS)

    Englman, R.; Yahalom, A.

    2003-01-01

    A Lagrangean for the dynamics of an electromagnetic field in a dispersive and dissipative material is constructed (adapting some ideas by Bekenstein and Hannay) and an expression for the energy density that is positive is obtained from it. The expression contains extra (sink) degrees of freedom that represent dissipating modes. In simplified cases the sink modes can be eliminated to yield an energy density expression in terms of the electromagnetic fields, the polarization and the magnetization only, but which contains parameters associated with the sink modes. The method of adding extra modes can be used to set up a Lagrangean formalism for dissipative systems in general, such that will reinstate time-translation invariance and will yield a unique energy density

  4. Solutions of nuclear pairing

    International Nuclear Information System (INIS)

    Balantekin, A. B.; Pehlivan, Y.

    2007-01-01

    We give the exact solution of orbit dependent nuclear pairing problem between two nondegenerate energy levels using the Bethe ansatz technique. Our solution reduces to previously solved cases in the appropriate limits including Richardson's treatment of reduced pairing in terms of rational Gaudin algebra operators

  5. High-pressure pair distribution function (PDF) measurement using high-energy focused x-ray beam

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Xinguo, E-mail: xhong@bnl.gov; Weidner, Donald J. [Mineral Physics Institute, Stony Brook University, Stony Brook, NY 11794 (United States); Ehm, Lars [Mineral Physics Institute, Stony Brook University, Stony Brook, NY 11794 (United States); National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973 (United States); Zhong, Zhong; Ghose, Sanjit [National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973 (United States); Duffy, Thomas S. [Department of Geosciences, Princeton University, Princeton, NJ 08544 (United States)

    2016-07-27

    In this paper, we report recent development of the high-pressure pair distribution function (HP-PDF) measurement technique using a focused high-energy X-ray beam coupled with a diamond anvil cell (DAC). The focusing optics consist of a sagittally bent Laue monochromator and Kirkpatrick-Baez (K–B) mirrors. This combination provides a clean high-energy X-ray beam suitable for HP-PDF research. Demonstration of the HP-PDF technique for nanocrystalline platinum under quasi-hydrostatic condition above 30 GPa is presented.

  6. Diffuse Waves and Energy Densities Near Boundaries

    Science.gov (United States)

    Sanchez-Sesma, F. J.; Rodriguez-Castellanos, A.; Campillo, M.; Perton, M.; Luzon, F.; Perez-Ruiz, J. A.

    2007-12-01

    Green function can be retrieved from averaging cross correlations of motions within a diffuse field. In fact, it has been shown that for an elastic inhomogeneous, anisotropic medium under equipartitioned, isotropic illumination, the average cross correlations are proportional to the imaginary part of Green function. For instance coda waves are due to multiple scattering and their intensities follow diffusive regimes. Coda waves and the noise sample the medium and effectively carry information along their paths. In this work we explore the consequences of assuming both source and receiver at the same point. From the observable side, the autocorrelation is proportional to the energy density at a given point. On the other hand, the imaginary part of the Green function at the source itself is finite because the singularity of Green function is restricted to the real part. The energy density at a point is proportional with the trace of the imaginary part of Green function tensor at the source itself. The Green function availability may allow establishing the theoretical energy density of a seismic diffuse field generated by a background equipartitioned excitation. We study an elastic layer with free surface and overlaying a half space and compute the imaginary part of the Green function for various depths. We show that the resulting spectrum is indeed closely related to the layer dynamic response and the corresponding resonant frequencies are revealed. One implication of present findings lies in the fact that spatial variations may be useful in detecting the presence of a target by its signature in the distribution of diffuse energy. These results may be useful in assessing the seismic response of a given site if strong ground motions are scarce. It suffices having a reasonable illumination from micro earthquakes and noise. We consider that the imaginary part of Green function at the source is a spectral signature of the site. The relative importance of the peaks of

  7. γ-rays from pair recombination in a travelling wave structure

    International Nuclear Information System (INIS)

    Bertolotti, M.; Sibilla, C.

    1978-01-01

    To obtain stimulated annihilation of pairs, two photon beams arriving from opposite directions are made to impinge with a region where e - - e + pairs are interacting, thus stimulating their recombination. At the exit of the interaction region photons are amplified by a factor β. The change in photon density is studied as a function of the length of the interaction region. The pair density needed to have a given gain is calculated and results to be proportional to log β 2 /(1+β)

  8. Idempotent Dirac density matrix for ten-electron central field inhomogeneous electron liquids in terms of electron- and kinetic energy-densities

    International Nuclear Information System (INIS)

    March, N.H.

    2006-08-01

    A differential equation for the Dirac density matrix γ(r, r'), given ground-state electron- and kinetic energy-densities, has been derived by March and Suhai for one- and two-level occupancy. For ten-electron spin-compensated spherical systems, it is shown here that γ ≡ γ[ρ, t g ] where ρ and t g are electron- and kinetic energy-densities. The philosophy of March and Suhai is confirmed beyond two-level filling. An important byproduct of the present approach is an explicit expression for the one-body potential of DFT in terms of the p-shell electron density. (author)

  9. Constraints on the cosmological relativistic energy density

    International Nuclear Information System (INIS)

    Zentner, Andrew R.; Walker, Terry P.

    2002-01-01

    We discuss bounds on the cosmological relativistic energy density as a function of redshift, reviewing the big bang nucleosynthesis and cosmic microwave background bounds, updating bounds from large scale structure, and introducing a new bound from the magnitude-redshift relation for type Ia supernovae. We conclude that the standard and well-motivated assumption that relativistic energy is negligible during recent epochs is not necessitated by extant data. We then demonstrate the utility of these bounds by constraining the mass and lifetime of a hypothetical massive big bang relic particle

  10. Numerical investigation of kinetic turbulence in relativistic pair plasmas - I. Turbulence statistics

    Science.gov (United States)

    Zhdankin, Vladimir; Uzdensky, Dmitri A.; Werner, Gregory R.; Begelman, Mitchell C.

    2018-02-01

    We describe results from particle-in-cell simulations of driven turbulence in collisionless, magnetized, relativistic pair plasma. This physical regime provides a simple setting for investigating the basic properties of kinetic turbulence and is relevant for high-energy astrophysical systems such as pulsar wind nebulae and astrophysical jets. In this paper, we investigate the statistics of turbulent fluctuations in simulations on lattices of up to 10243 cells and containing up to 2 × 1011 particles. Due to the absence of a cooling mechanism in our simulations, turbulent energy dissipation reduces the magnetization parameter to order unity within a few dynamical times, causing turbulent motions to become sub-relativistic. In the developed stage, our results agree with predictions from magnetohydrodynamic turbulence phenomenology at inertial-range scales, including a power-law magnetic energy spectrum with index near -5/3, scale-dependent anisotropy of fluctuations described by critical balance, lognormal distributions for particle density and internal energy density (related by a 4/3 adiabatic index, as predicted for an ultra-relativistic ideal gas), and the presence of intermittency. We also present possible signatures of a kinetic cascade by measuring power-law spectra for the magnetic, electric and density fluctuations at sub-Larmor scales.

  11. High energy density supercapacitors using macroporous kitchen sponges

    KAUST Repository

    Chen, Wei

    2012-01-01

    Macroporous, low-cost and recyclable kitchen sponges are explored as effective electrode platforms for supercapacitor devices. A simple and scalable process has been developed to fabricate MnO 2-carbon nanotube (CNT)-sponge supercapacitor electrodes using ordinary kitchen sponges. Two organic electrolytes (1 M of tetraethylammonium tetrafluoroborate (Et 4NBF 4) in propylene carbonate (PC), 1 M of LiClO 4 in PC) are utilized with the sponge-based electrodes to improve the energy density of the symmetrical supercapacitors. Compared to aqueous electrolyte (1 M of Na 2SO 4 in H 2O), the energy density of supercapacitors tripled in Et 4NBF 4 electrolyte, and further increased by six times in LiClO 4 electrolyte. The long-term cycling performance in different electrolytes was examined and the morphology changes of the electrode materials were also studied. The good electrochemical performance in both aqueous and organic electrolytes indicates that the MnO 2-CNT-sponge is a promising low-cost electrode for energy storage systems. © 2012 The Royal Society of Chemistry.

  12. Electron-positron pair production in Coulomb collisions at ultrarelativistic energies

    International Nuclear Information System (INIS)

    Vane, C.R.; Datz, S.; Dittner, P.F.; Krause, H.F.; Bottcher, C.; Strayer, M.; Schuch, R.; Gao, H.; Hutton, R.

    1993-01-01

    We have measured angular and momentum distributions for electrons and positrons created as pairs in peripheral collisions of 6.4 TeV bare sulfur ions with fixed targets of Al, Pd, and Au. Singly- and doubly-differential cross sections have been determined for 1--17 MeV/c electrons and positrons detected independently and in coincidence as pairs. Integrated yields for pair production are found to vary as the square of the target nuclear charge. Relative angular and momentum differential cross sections are effectively target independent. Probability distributions for the pair total momentum, the positron fraction of the pair momentum, and the pair traverse momentum have been derived from the coincident electron-positron data

  13. Flexible asymmetric supercapacitors with high energy and high power density in aqueous electrolytes

    Science.gov (United States)

    Cheng, Yingwen; Zhang, Hongbo; Lu, Songtao; Varanasi, Chakrapani V.; Liu, Jie

    2013-01-01

    Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO2, activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of the original capacitance retained when the scan rate was increased from 2 mV s-1 to 500 mV s-1. Owing to the unique composite structure, these supercapacitors were able to deliver high energy density (24 W h kg-1) under high power density (7.8 kW kg-1) conditions. These features could enable supercapacitor based energy storage systems to be very attractive for a variety of critical applications, such as the power sources in hybrid electric vehicles and the back-up powers for wind and solar energy, where both high energy density and high power density are required.Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO2, activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of

  14. Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics

    Science.gov (United States)

    Kou, Liang; Huang, Tieqi; Zheng, Bingna; Han, Yi; Zhao, Xiaoli; Gopalsamy, Karthikeyan; Sun, Haiyan; Gao, Chao

    2014-01-01

    Yarn supercapacitors have great potential in future portable and wearable electronics because of their tiny volume, flexibility and weavability. However, low-energy density limits their development in the area of wearable high-energy density devices. How to enhance their energy densities while retaining their high-power densities is a critical challenge for yarn supercapacitor development. Here we propose a coaxial wet-spinning assembly approach to continuously spin polyelectrolyte-wrapped graphene/carbon nanotube core-sheath fibres, which are used directly as safe electrodes to assembly two-ply yarn supercapacitors. The yarn supercapacitors using liquid and solid electrolytes show ultra-high capacitances of 269 and 177 mF cm−2 and energy densities of 5.91 and 3.84 μWh cm−2, respectively. A cloth supercapacitor superior to commercial capacitor is further interwoven from two individual 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and excellent performance of yarn supercapacitors paves the way to wearable and safe electronics. PMID:24786366

  15. Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics

    Science.gov (United States)

    Kou, Liang; Huang, Tieqi; Zheng, Bingna; Han, Yi; Zhao, Xiaoli; Gopalsamy, Karthikeyan; Sun, Haiyan; Gao, Chao

    2014-05-01

    Yarn supercapacitors have great potential in future portable and wearable electronics because of their tiny volume, flexibility and weavability. However, low-energy density limits their development in the area of wearable high-energy density devices. How to enhance their energy densities while retaining their high-power densities is a critical challenge for yarn supercapacitor development. Here we propose a coaxial wet-spinning assembly approach to continuously spin polyelectrolyte-wrapped graphene/carbon nanotube core-sheath fibres, which are used directly as safe electrodes to assembly two-ply yarn supercapacitors. The yarn supercapacitors using liquid and solid electrolytes show ultra-high capacitances of 269 and 177 mF cm-2 and energy densities of 5.91 and 3.84 μWh cm-2, respectively. A cloth supercapacitor superior to commercial capacitor is further interwoven from two individual 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and excellent performance of yarn supercapacitors paves the way to wearable and safe electronics.

  16. Study of Electron-Pair Spectroscopy in Pb-Pb Collisions at LHC

    CERN Document Server

    CERN. Geneva

    1993-01-01

    Among observables that have been proposed as signals of quark gluon plasma the lepton pairs from decays of vector bosons r, w, j, J/Y, U,... play important role. Effects such as the J/Y suppression, chiral symmetry restoration, strangeness enhancement and fast "clock" for the fireball lifetime are associated with possibilities of the lepton-pair spectroscopy in PbPb collisions at the LHC energies. In PbPb collisions the high particle density in central rapidity region is expected and therefore one has first of all to verify the feasibility of experiments aimed to measurement of cross sections, width and positions of vector resonances. For this purpose the programme LHCWPT has been developed which simulates production and two-and three-body decays of the ¹¡, h°, h, r, w, f, J/Y, U and Drell-Yan pairs in central rapidity region and also a detection of electrons and positrons in HEAVY ION DEDICATED EXPERIMENT.

  17. Functional derivative of noninteracting kinetic energy density functional

    International Nuclear Information System (INIS)

    Liu Shubin; Ayers, Paul W.

    2004-01-01

    Proofs from different theoretical frameworks, namely, the Hohenbergh-Kohn theorems, the Kohn-Sham scheme, and the first-order density matrix representation, have been presented in this paper to show that the functional derivative of the noninteracting kinetic energy density functional can uniquely be expressed as the negative of the Kohn-Sham effective potential, arbitrary only to an additive orbital-independent constant. Key points leading to the current result as well as confusion about the quantity in the literature are briefly discussed

  18. An x-ray backlit Talbot-Lau deflectometer for high-energy-density electron density diagnostics

    Science.gov (United States)

    Valdivia, M. P.; Stutman, D.; Stoeckl, C.; Theobald, W.; Mileham, C.; Begishev, I. A.; Bromage, J.; Regan, S. P.

    2016-02-01

    X-ray phase-contrast techniques can measure electron density gradients in high-energy-density plasmas through refraction induced phase shifts. An 8 keV Talbot-Lau interferometer consisting of free standing ultrathin gratings was deployed at an ultra-short, high-intensity laser system using K-shell emission from a 1-30 J, 8 ps laser pulse focused on thin Cu foil targets. Grating survival was demonstrated for 30 J, 8 ps laser pulses. The first x-ray deflectometry images obtained under laser backlighting showed up to 25% image contrast and thus enabled detection of electron areal density gradients with a maximum value of 8.1 ± 0.5 × 1023 cm-3 in a low-Z millimeter sized sample. An electron density profile was obtained from refraction measurements with an error of x-ray source-size, similar to conventional radiography.

  19. Pairing States of Spin-3/2 Fermions: Symmetry-Enforced Topological Gap Functions

    Science.gov (United States)

    Venderbos, Jörn W. F.; Savary, Lucile; Ruhman, Jonathan; Lee, Patrick A.; Fu, Liang

    2018-01-01

    We study the topological properties of superconductors with paired j =3/2 quasiparticles. Higher spin Fermi surfaces can arise, for instance, in strongly spin-orbit coupled band-inverted semimetals. Examples include the Bi-based half-Heusler materials, which have recently been established as low-temperature and low-carrier density superconductors. Motivated by this experimental observation, we obtain a comprehensive symmetry-based classification of topological pairing states in systems with higher angular momentum Cooper pairing. Our study consists of two main parts. First, we develop the phenomenological theory of multicomponent (i.e., higher angular momentum) pairing by classifying the stationary points of the free energy within a Ginzburg-Landau framework. Based on the symmetry classification of stationary pairing states, we then derive the symmetry-imposed constraints on their gap structures. We find that, depending on the symmetry quantum numbers of the Cooper pairs, different types of topological pairing states can occur: fully gapped topological superconductors in class DIII, Dirac superconductors, and superconductors hosting Majorana fermions. Notably, we find a series of nematic fully gapped topological superconductors, as well as double- and triple-Dirac superconductors, with quadratic and cubic dispersion, respectively. Our approach, applied here to the case of j =3/2 Cooper pairing, is rooted in the symmetry properties of pairing states, and can therefore also be applied to other systems with higher angular momentum and high-spin pairing. We conclude by relating our results to experimentally accessible signatures in thermodynamic and dynamic probes.

  20. Experimental and theoretical study of directional effects on radiation and pair creation in crystal at energies near 100 GeV

    International Nuclear Information System (INIS)

    Belkacem, A.

    1986-07-01

    We investigated the electron-positron pair production from incident photons on a thin crystal. When the photon energy is higher than about 30 GeV, the pair production rate from a photon beam aligned along a crystal direction is higher than the rate measured with an amorphous target (Bethe-Heitler value). In contrast with what was observed for a random orientation (or with an amorphous target) the pair production rate increases sharply with the photon energy. We also investigated the radiation emitted by high energy electrons and positrons (70-200 GeV) along a crystal direction. The intensity of the radiation was found to be extremely high. The increase of the intensity of these two electromagnetic processes (radiation and pair creation) was still observed for incident angles much larger than the channeling critical angle. Thus, a theory based on the channeling phenomenon is not able to explain such observations. In order to understand these new phenomena we developed a new theoretical approach based on the electromagnetic interaction in strong fields. The predictions of this theory on the pair production are in very good agreement with the measurements. The calculations of the radiation are in quantitative agreement with measurements for incident angles larger than the channeling critical angle. This agreement is only qualitative for incident angles smaller than the critical angle [fr

  1. Extreme states of matter high energy density physics

    CERN Document Server

    Fortov, Vladimir E

    2016-01-01

    With its many beautiful colour pictures, this book gives fascinating insights into the unusual forms and behaviour of matter under extremely high pressures and temperatures. These extreme states are generated, among other things, by strong shock, detonation and electric explosion waves, dense laser beams,electron and ion beams, hypersonic entry of spacecraft into dense atmospheres of planets, and in many other situations characterized by extremely high pressures and temperatures.Written by one of the world's foremost experts on the topic, this book will inform and fascinate all scientists dealing with materials properties and physics, and also serve as an excellent introduction to plasma-, shock-wave and high-energy-density physics for students and newcomers seeking an overview. This second edition is thoroughly revised and expanded, in particular with new material on high energy-density physics, nuclear explosions and other nuclear transformation processes.

  2. Chemical bond as a test of density-gradient expansions for kinetic and exchange energies

    International Nuclear Information System (INIS)

    Perdew, J.P.; Levy, M.; Painter, G.S.; Wei, S.; Lagowski, J.B.

    1988-01-01

    Errors in kinetic and exchange contributions to the molecular bonding energy are assessed for approximate density functionals by reference to near-exact Hartree-Fock values. From the molecular calculations of Allan et al. and of Lee and Ghosh, it is demonstrated that the density-gradient expansion does not accurately describe the noninteracting kinetic contribution to the bonding energy, even when this expansion is carried to fourth order and applied in its spin-density-functional form to accurate Hartree-Fock densities. In a related study, it is demonstrated that the overbinding of molecules such as N 2 and F 2 , which occurs in the local-spin-density (LSD) approximation for the exchange-correlation energy, is not attributable to errors in the self-consistent LSD densities. Contrary to expectations based upon the Gunnarsson-Jones nodality argument, it is found that the LSD approximation for the exchange energy can seriously overbind a molecule even when bonding does not create additional nodes in the occupied valence orbitals. LSD and exact values for the exchange contribution to the bonding energy are displayed and discussed for several molecules

  3. High energy density and efficiency achieved in nanocomposite film capacitors via structure modulation

    Science.gov (United States)

    Zeng, Yi; Shen, Zhong-Hui; Shen, Yang; Lin, Yuanhua; Nan, Ce-Wen

    2018-03-01

    Flexible dielectric polymer films with high energy storage density and high charge-discharge efficiency have been considered as promising materials for electrical power applications. Here, we design hierarchical structured nanocomposite films using nonlinear polymer poly(vinylidene fluoride-HFP) [P(VDF-HFP)] with inorganic h-boron nitride (h-BN) nanosheets by electrospinning and hot-pressing methods. Our results show that the addition of h-BN nanosheets and the design of the hierarchical multilayer structure in the nanocomposites can remarkably enhance the charge-discharge efficiency and energy density. A high charge-discharge efficiency of 78% and an energy density of 21 J/cm3 can be realized in the 12-layered PVDF/h-BN nanocomposite films. Phase-field simulation results reveal that the spatial distribution of the electric field in these hierarchical structured films affects the charge-discharge efficiency and energy density. This work provides a feasible route, i.e., structure modulation, to improve the energy storage performances for nanocomposite films.

  4. [Recommended values of energy density in soup or gruel-like foods, for feeding of preschool children].

    Science.gov (United States)

    Araya, H; Alviña, M; Vera, G; Pak, N

    1991-03-01

    The low energy density of the diets has been proposed by several authors as an essential factor which conditions the inadequate energy intake of preschool children of developing countries. However, there are few controlled studies in relation to the volumes which children are able to consume when energy density changes. The objective of this research was to establish recommended values of energy density for preparations with a soup or gruel consistency. The study was carried out in 100 preschool children from 3 to 4 years old who attended a Day Care Center in Santiago, Chile. Six formulas of a mixture of extruded pea-rice with different energy densities and viscosities: 0.8, 1.2 and 1.6 kcal/g and 3,000 and 9,000 cp. were studied. These experimental conditions were obtained modifying the product concentration and adding malt flour. Food consumption was determined at lunch time. Energy adequacy was calculated using the 1985 FAO-OMS-UNU requirements. Children increased significantly their energy intake when energy density of both types of consistency, soup or gruel, was higher. Energy adequacy ranged from 15% when preparations had an energy density of 0.8 kcal/g to 35%, when the preparations had an energy density of 1.6 kcal/g. The formulas which had 1.6 kcal/g fulfilled 100% of the energy requirements of preschool children for lunch time, and should be the recommended energy density for soup or gruels, when they are given as the only food. The energy density of 1.2 kcal/g needs a food complement which supplies 120 kcal, and lower values would be inadequate for preschool children feeding purposes.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Watson-Crick Base Pairing, Electronic and Photophysical Properties of Triazole Modified Adenine Analogues: A Computational Study

    KAUST Repository

    Das, Shubhajit

    2015-09-17

    We employ first-principles Density Functional Theory (DFT) and time-dependent DFT (TDDFT) to elucidate structural, electronic and optical properties of a few recently reported triazole adenine nucleobase analogues. The results are compared against the findings obtained for both natural adenine nucleobase and available experimental data. The optical absorption of these adenine analogues are calculated both in gas-phase and in solvent (methanol) using Polarized Continuum Model (PCM). We find that all the analogues show a red-shifted absorption profile as compared to adenine. Our simulated emission spectra in solvent compare fairly well with experimentally observed results. We investigate base paring ability of these adenine analogues with thymine. The calculations on the intrinsic stability of these base pairs ascertain that all the adenine analogues form the hydrogen bonded Watson-Crick base pair with similar H-bonding energy as obtained for natural adenine-thymine base pair. In our study, we provide a microscopic origin of the low-energy absorption and emission peaks, observed experimentally.

  6. Watson-Crick Base Pairing, Electronic and Photophysical Properties of Triazole Modified Adenine Analogues: A Computational Study

    KAUST Repository

    Das, Shubhajit; Samanta, Pralok Kumar; Pati, Swapan

    2015-01-01

    We employ first-principles Density Functional Theory (DFT) and time-dependent DFT (TDDFT) to elucidate structural, electronic and optical properties of a few recently reported triazole adenine nucleobase analogues. The results are compared against the findings obtained for both natural adenine nucleobase and available experimental data. The optical absorption of these adenine analogues are calculated both in gas-phase and in solvent (methanol) using Polarized Continuum Model (PCM). We find that all the analogues show a red-shifted absorption profile as compared to adenine. Our simulated emission spectra in solvent compare fairly well with experimentally observed results. We investigate base paring ability of these adenine analogues with thymine. The calculations on the intrinsic stability of these base pairs ascertain that all the adenine analogues form the hydrogen bonded Watson-Crick base pair with similar H-bonding energy as obtained for natural adenine-thymine base pair. In our study, we provide a microscopic origin of the low-energy absorption and emission peaks, observed experimentally.

  7. Coherent pair creation from beam-beam interaction

    International Nuclear Information System (INIS)

    Chen, Pisin.

    1989-09-01

    It has recently been recognized that in future linear colliders, there is a finite probability that the beamstrahlung photons will turn into e + e - pairs induced by the same beam-beam field, and this would potentially cause background problems. In this paper, we first review the probability of such a coherent pair creation process. It is seen that the constraint on the beamstrahlung parameter, Υ, is tight of these coherent pairs to be totally suppressed. We then point out that there exists a minimum energy for the pair-created particles, which scales as ∼1/5Υ. When combining this condition with the deflection angle for the low-energy particles, the constraint on the allowable Υ value is much relaxed. Finally, we calculate the effective cross section for producing the weak bosons by the low-energy e + e - pairs. It is shown that these cross sections are substantial for Υ > 1. We suggest that this effect can help to autoscan the particle spectrum in the high energy frontier. 10 refs., 2 figs

  8. High energy density fusing using the Compact Torus

    International Nuclear Information System (INIS)

    Hartman, C.W.

    1989-01-01

    My remarks are concerned with employing the Compact Torus magnetic field configuration to produce fusion energy. In particular, I would like to consider high energy density regimes where the pressures generated extend well beyond the strength of materials. Under such conditions, where nearby walls are vaporized and pushed aside each shot, the technological constraints are very different from usual magnetic fusion and may admit opportunities for an improved fusion reactor design. 5 refs., 3 figs

  9. Effects of Consuming Preloads with Different Energy Density and Taste Quality on Energy Intake and Postprandial Blood Glucose.

    Science.gov (United States)

    Tey, Siew Ling; Salleh, Nurhazwani; Henry, Christiani Jeyakumar; Forde, Ciaran G

    2018-01-31

    Consumption of reduced energy dense foods and drink has the potential to reduce energy intake and postprandial blood glucose concentrations. In addition, the taste quality of a meal (e.g., sweet or savoury) may play a role in satiation and food intake. The objective of this randomised crossover study was to examine whether energy density and taste quality has an impact on energy intake and postprandial blood glucose response. Using a preload design, participants were asked to consume a sweet ("Cheng Teng") or a savoury (broth) preload soup in high energy density (HED; around 0.50 kcal/g; 250 kcal) or low energy density (LED; around 0.12 kcal/g; 50 kcal) in mid-morning and an ad libitum lunch was provided an hour after the preload. Participants recorded their food intake for the rest of the day after they left the study site. Energy compensation and postprandial blood glucose response were measured in 32 healthy lean males (mean age = 28.9 years, mean BMI = 22.1 kg/m²). There was a significant difference in ad libitum lunch intake between treatments ( p = 0.012), with higher intake in sweet LED and savoury LED compared to sweet HED and savoury HED. Energy intake at subsequent meals and total daily energy intake did not differ between the four treatments (both p ≥ 0.214). Consumption of HED preloads resulted in a larger spike in postprandial blood glucose response compared with LED preloads, irrespective of taste quality ( p < 0.001). Energy density rather than taste quality plays an important role in energy compensation and postprandial blood glucose response. This suggests that regular consumption of low energy-dense foods has the potential to reduce overall energy intake and to improve glycemic control.

  10. Effects of Consuming Preloads with Different Energy Density and Taste Quality on Energy Intake and Postprandial Blood Glucose

    Directory of Open Access Journals (Sweden)

    Siew Ling Tey

    2018-01-01

    Full Text Available Consumption of reduced energy dense foods and drink has the potential to reduce energy intake and postprandial blood glucose concentrations. In addition, the taste quality of a meal (e.g., sweet or savoury may play a role in satiation and food intake. The objective of this randomised crossover study was to examine whether energy density and taste quality has an impact on energy intake and postprandial blood glucose response. Using a preload design, participants were asked to consume a sweet (“Cheng Teng” or a savoury (broth preload soup in high energy density (HED; around 0.50 kcal/g; 250 kcal or low energy density (LED; around 0.12 kcal/g; 50 kcal in mid-morning and an ad libitum lunch was provided an hour after the preload. Participants recorded their food intake for the rest of the day after they left the study site. Energy compensation and postprandial blood glucose response were measured in 32 healthy lean males (mean age = 28.9 years, mean BMI = 22.1 kg/m2. There was a significant difference in ad libitum lunch intake between treatments (p = 0.012, with higher intake in sweet LED and savoury LED compared to sweet HED and savoury HED. Energy intake at subsequent meals and total daily energy intake did not differ between the four treatments (both p ≥ 0.214. Consumption of HED preloads resulted in a larger spike in postprandial blood glucose response compared with LED preloads, irrespective of taste quality (p < 0.001. Energy density rather than taste quality plays an important role in energy compensation and postprandial blood glucose response. This suggests that regular consumption of low energy-dense foods has the potential to reduce overall energy intake and to improve glycemic control.

  11. Graphene and carbon nanotube composite electrodes for supercapacitors with ultra-high energy density.

    Science.gov (United States)

    Cheng, Qian; Tang, Jie; Ma, Jun; Zhang, Han; Shinya, Norio; Qin, Lu-Chang

    2011-10-21

    We describe a graphene and single-walled carbon nanotube (SWCNT) composite film prepared by a blending process for use as electrodes in high energy density supercapacitors. Specific capacitances of 290.6 F g(-1) and 201.0 F g(-1) have been obtained for a single electrode in aqueous and organic electrolytes, respectively, using a more practical two-electrode testing system. In the organic electrolyte the energy density reached 62.8 Wh kg(-1) and the power density reached 58.5 kW kg(-1). The addition of single-walled carbon nanotubes raised the energy density by 23% and power density by 31% more than the graphene electrodes. The graphene/CNT electrodes exhibited an ultra-high energy density of 155.6 Wh kg(-1) in ionic liquid at room temperature. In addition, the specific capacitance increased by 29% after 1000 cycles in ionic liquid, indicating their excellent cyclicity. The SWCNTs acted as a conductive additive, spacer, and binder in the graphene/CNT supercapacitors. This work suggests that our graphene/CNT supercapacitors can be comparable to NiMH batteries in performance and are promising for applications in hybrid vehicles and electric vehicles. This journal is © the Owner Societies 2011

  12. Free energy landscape and transition pathways from Watson–Crick to Hoogsteen base pairing in free duplex DNA

    Science.gov (United States)

    Yang, Changwon; Kim, Eunae; Pak, Youngshang

    2015-01-01

    Houghton (HG) base pairing plays a central role in the DNA binding of proteins and small ligands. Probing detailed transition mechanism from Watson–Crick (WC) to HG base pair (bp) formation in duplex DNAs is of fundamental importance in terms of revealing intrinsic functions of double helical DNAs beyond their sequence determined functions. We investigated a free energy landscape of a free B-DNA with an adenosine–thymine (A–T) rich sequence to probe its conformational transition pathways from WC to HG base pairing. The free energy landscape was computed with a state-of-art two-dimensional umbrella molecular dynamics simulation at the all-atom level. The present simulation showed that in an isolated duplex DNA, the spontaneous transition from WC to HG bp takes place via multiple pathways. Notably, base flipping into the major and minor grooves was found to play an important role in forming these multiple transition pathways. This finding suggests that naked B-DNA under normal conditions has an inherent ability to form HG bps via spontaneous base opening events. PMID:26250116

  13. Sr-doped Lanthanum Nickelate Nanofibers for High Energy Density Supercapacitors

    International Nuclear Information System (INIS)

    Cao, Yi; Lin, Baoping; Sun, Ying; Yang, Hong; Zhang, Xueqin

    2015-01-01

    Highlights: • The electrode made by LNF-0.7 possessed excellent performance (719 F g −1 ) at Na 2 SO 4 electrolyte • LNF-0.7//LNF-0.7 symmetric supercapacitor device were firstly prepared • The maximum energy density of 81.4 Wh·kg −1 are achieved at a power density of 500W·kg −1 • This symmetric supercapacitor also shows an excellent cycling life - Abstract: The series La x Sr 1−x NiO 3−δ (0.3≤x≤1) nanofibers (LNF-x) samples are prepared by using electrospun method. We investigate the structure and the electrochemical properties of LNF-x in detail. As a result, LNF-x nanofibers present a perovskite structure, and the LNF-0.7 sample with high specific surface area display remarkable performance as an electrode material for supercapacitors. The maximum specific capacitance value of 719 F·g −1 at a current density of 2 A·g −1 , which retains 505 F·g −1 at a high current density of 20 A·g −1 , is obtained for LNF-0.7 electrode in 1 M Na 2 SO 4 aqueous electrolyte. Moreover, the LNF-0.7//LNF-0.7 symmetric supercapacitor device using 1 M Na 2 SO 4 aqueous solution is successfully demonstrated. The capacitor device can operate at a cell voltage as high as 2 V, and it exhibits an energy density of 30.5 Wh·kg −1 at a high power density of 10 kW·kg −1 and a high energy density of 81.4 Wh·kg −1 at a low power density of 500 W·kg −1 . More importantly, this symmetric supercapacitor also shows an excellent cycling performance with 90% specific capacitance retention after 2000 charging and discharging cycles. Those results offer a suitable design of electrode materials for high-performance supercapacitors

  14. Measurements of Coulomb Cross Section for Production of Direct Electron-pairs by High Energy Ions at the CERN SPS

    CERN Multimedia

    2002-01-01

    QED predicts copious direct electron pair production by ultrarelativistic heavy nuclei in a high Z medium such as nuclear emulsion. First order QED calculations (combined screening and non-screening) for this process show that 1000@+32 electron pairs above 100~keV energy) should be emitted for a total |1|6O track length of 10.9~m in nuclear emulsion at 200~GeV/AMU. Emulsion exposures with oxygen (and other nuclei if available) at 60 and 200~GeV/AMU will be used to calibrate the energy dependent cross section @s~@j~(1n~E)|2|-|3, whose exponent depends on atomic screening. The oxygen tracks in the developed emulsions will be scanned with a microscope, and the number of direct electron pairs will be counted for individual tracks. The exposed stacks will contain sufficient emulsion (and CR39 plastic to check for possible interactions) that adequate path length will be available for exposures to @$>$~10|4~ions at each energy and ion species. \\\\ \\\\ If the absolute value of this cross section is confirmed as large a...

  15. Globally optimal superconducting magnets part I: minimum stored energy (MSE) current density map.

    Science.gov (United States)

    Tieng, Quang M; Vegh, Viktor; Brereton, Ian M

    2009-01-01

    An optimal current density map is crucial in magnet design to provide the initial values within search spaces in an optimization process for determining the final coil arrangement of the magnet. A strategy for obtaining globally optimal current density maps for the purpose of designing magnets with coaxial cylindrical coils in which the stored energy is minimized within a constrained domain is outlined. The current density maps obtained utilising the proposed method suggests that peak current densities occur around the perimeter of the magnet domain, where the adjacent peaks have alternating current directions for the most compact designs. As the dimensions of the domain are increased, the current density maps yield traditional magnet designs of positive current alone. These unique current density maps are obtained by minimizing the stored magnetic energy cost function and therefore suggest magnet coil designs of minimal system energy. Current density maps are provided for a number of different domain arrangements to illustrate the flexibility of the method and the quality of the achievable designs.

  16. Advanced intermediate temperature sodium-nickel chloride batteries with ultra-high energy density

    Science.gov (United States)

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y.; Meinhardt, Kerry D.; Chang, Hee Jung; Canfield, Nathan L.; Sprenkle, Vincent L.

    2016-02-01

    Sodium-metal halide batteries have been considered as one of the more attractive technologies for stationary electrical energy storage, however, they are not used for broader applications despite their relatively well-known redox system. One of the roadblocks hindering market penetration is the high-operating temperature. Here we demonstrate that planar sodium-nickel chloride batteries can be operated at an intermediate temperature of 190 °C with ultra-high energy density. A specific energy density of 350 Wh kg-1, higher than that of conventional tubular sodium-nickel chloride batteries (280 °C), is obtained for planar sodium-nickel chloride batteries operated at 190 °C over a long-term cell test (1,000 cycles), and it attributed to the slower particle growth of the cathode materials at the lower operating temperature. Results reported here demonstrate that planar sodium-nickel chloride batteries operated at an intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs.

  17. Applications of Skyrme energy-density functional to fusion reactions spanning the fusion barriers

    International Nuclear Information System (INIS)

    Liu Min; Wang, Ning; Li Zhuxia; Wu Xizhen; Zhao Enguang

    2006-01-01

    The Skyrme energy density functional has been applied to the study of heavy-ion fusion reactions. The barriers for fusion reactions are calculated by the Skyrme energy density functional with proton and neutron density distributions determined by using restricted density variational (RDV) method within the same energy density functional together with semi-classical approach known as the extended semi-classical Thomas-Fermi method. Based on the fusion barrier obtained, we propose a parametrization of the empirical barrier distribution to take into account the multi-dimensional character of real barrier and then apply it to calculate the fusion excitation functions in terms of barrier penetration concept. A large number of measured fusion excitation functions spanning the fusion barriers can be reproduced well. The competition between suppression and enhancement effects on sub-barrier fusion caused by neutron-shell-closure and excess neutron effects is studied

  18. Learning about the energy density of liquid and semi-solid foods

    NARCIS (Netherlands)

    Hogenkamp, P.S.; Stafleu, A.; Mars, M.; Graaf C. de

    2012-01-01

    Background:People learn about a food's satiating capacity by exposure and consequently adjust their energy intake.Objective:To investigate the effect of energy density and texture on subsequent energy intake adjustments during repeated consumption.Design:In a randomized crossover design,

  19. Learning about the energy density of liquid and semi-solid foods

    NARCIS (Netherlands)

    Hogenkamp, P.S.; Stafleu, A.; Mars, M.; Graaf, de C.

    2012-01-01

    BACKGROUND: People learn about a food's satiating capacity by exposure and consequently adjust their energy intake. OBJECTIVE: To investigate the effect of energy density and texture on subsequent energy intake adjustments during repeated consumption. DESIGN: In a randomized crossover design,

  20. Ambient RF energy scavenging: GSM and WLAN power density measurements

    NARCIS (Netherlands)

    Visser, H.J.; Reniers, A.C.F.; Theeuwes, J.A.C.

    2009-01-01

    To assess the feasibility of ambient RF energy scavenging, a survey of expected power density levels distant from GSM-900 and GSM-1800 base stations has been conducted and power density measurements have been performed in a WLAN environment. It appears that for distances ranging from 25 m to 100 m

  1. Comment on 'Kinetic energy as a density functional'

    International Nuclear Information System (INIS)

    Holas, A.; March, N.H.

    2002-01-01

    In a recent paper, Nesbet [Phys. Rev. A 65, 010502(R) (2001)] has proposed dropping ''the widespread but unjustified assumption that the existence of a ground-state density functional for the kinetic energy, T s [ρ], of an N-electron system implies the existence of a density-functional derivative, δT s [ρ]/δρ(r), equivalent to a local potential function,'' because, according to his arguments, this derivative 'has the mathematical character of a linear operator that acts on orbital wave functions'. Our Comment demonstrates that the statement called by Nesbet an 'unjustified assumption' happens, in fact, to be a rigorously proven theorem. Therefore, his previous conclusions stemming from his different view of this derivative, which undermined the foundations of density-functional theory, can be discounted

  2. Energy hyperspace for stacking interaction in AU/AU dinucleotide step: Dispersion-corrected density functional theory study.

    Science.gov (United States)

    Mukherjee, Sanchita; Kailasam, Senthilkumar; Bansal, Manju; Bhattacharyya, Dhananjay

    2014-01-01

    Double helical structures of DNA and RNA are mostly determined by base pair stacking interactions, which give them the base sequence-directed features, such as small roll values for the purine-pyrimidine steps. Earlier attempts to characterize stacking interactions were mostly restricted to calculations on fiber diffraction geometries or optimized structure using ab initio calculations lacking variation in geometry to comment on rather unusual large roll values observed in AU/AU base pair step in crystal structures of RNA double helices. We have generated stacking energy hyperspace by modeling geometries with variations along the important degrees of freedom, roll, and slide, which were chosen via statistical analysis as maximally sequence dependent. Corresponding energy contours were constructed by several quantum chemical methods including dispersion corrections. This analysis established the most suitable methods for stacked base pair systems despite the limitation imparted by number of atom in a base pair step to employ very high level of theory. All the methods predict negative roll value and near-zero slide to be most favorable for the purine-pyrimidine steps, in agreement with Calladine's steric clash based rule. Successive base pairs in RNA are always linked by sugar-phosphate backbone with C3'-endo sugars and this demands C1'-C1' distance of about 5.4 Å along the chains. Consideration of an energy penalty term for deviation of C1'-C1' distance from the mean value, to the recent DFT-D functionals, specifically ωB97X-D appears to predict reliable energy contour for AU/AU step. Such distance-based penalty improves energy contours for the other purine-pyrimidine sequences also. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 107-120, 2014. Copyright © 2013 Wiley Periodicals, Inc.

  3. PAIR PRODUCTION IN LOW-LUMINOSITY GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Moscibrodzka, M.; Gammie, C. F.; Dolence, J. C.; Shiokawa, H.

    2011-01-01

    Electron-positron pairs may be produced near accreting black holes by a variety of physical processes, and the resulting pair plasma may be accelerated and collimated into a relativistic jet. Here, we use a self-consistent dynamical and radiative model to investigate pair production by γγ collisions in weakly radiative accretion flows around a black hole of mass M and accretion rate M-dot . Our flow model is drawn from general relativistic magnetohydrodynamic simulations, and our radiation field is computed by a Monte Carlo transport scheme assuming the electron distribution function is thermal. We argue that the pair production rate scales as r -6 M -1 M-dot 6 . We confirm this numerically and calibrate the scaling relation. This relation is self-consistent in a wedge in M, M-dot parameter space. If M-dot is too low the implied pair density over the poles of the black hole is below the Goldreich-Julian density and γγ pair production is relatively unimportant; if M-dot is too high the models are radiatively efficient. We also argue that for a power-law spectrum the pair production rate should scale with the observables L X ≡ X-ray luminosity and M as L 2 X M -4 . We confirm this numerically and argue that this relation likely holds even for radiatively efficient flows. The pair production rates are sensitive to black hole spin and to the ion-electron temperature ratio which are fixed in this exploratory calculation. We finish with a brief discussion of the implications for Sgr A* and M87.

  4. Foundations of high-energy-density physics physical processes of matter at extreme conditions

    CERN Document Server

    Larsen, Jon

    2017-01-01

    High-energy-density physics explores the dynamics of matter at extreme conditions. This encompasses temperatures and densities far greater than we experience on Earth. It applies to normal stars, exploding stars, active galaxies, and planetary interiors. High-energy-density matter is found on Earth in the explosion of nuclear weapons and in laboratories with high-powered lasers or pulsed-power machines. The physics explored in this book is the basis for large-scale simulation codes needed to interpret experimental results whether from astrophysical observations or laboratory-scale experiments. The key elements of high-energy-density physics covered are gas dynamics, ionization, thermal energy transport, and radiation transfer, intense electromagnetic waves, and their dynamical coupling. Implicit in this is a fundamental understanding of hydrodynamics, plasma physics, atomic physics, quantum mechanics, and electromagnetic theory. Beginning with a summary of the topics and exploring the major ones in depth, thi...

  5. Total-energy Assisted Tight-binding Method Based on Local Density Approximation of Density Functional Theory

    Science.gov (United States)

    Fujiwara, Takeo; Nishino, Shinya; Yamamoto, Susumu; Suzuki, Takashi; Ikeda, Minoru; Ohtani, Yasuaki

    2018-06-01

    A novel tight-binding method is developed, based on the extended Hückel approximation and charge self-consistency, with referring the band structure and the total energy of the local density approximation of the density functional theory. The parameters are so adjusted by computer that the result reproduces the band structure and the total energy, and the algorithm for determining parameters is established. The set of determined parameters is applicable to a variety of crystalline compounds and change of lattice constants, and, in other words, it is transferable. Examples are demonstrated for Si crystals of several crystalline structures varying lattice constants. Since the set of parameters is transferable, the present tight-binding method may be applicable also to molecular dynamics simulations of large-scale systems and long-time dynamical processes.

  6. Calculations of energy levels and electromagnetic properties for tellurium pair isotopes, by unified method

    International Nuclear Information System (INIS)

    Teixeira, R.R.P.

    1988-01-01

    Calculations with the Unified Model (vibrator coupled to two particles), of the energy levels and the eletromagnetic properties have been performed and compared with the twelve pair isotopes from tellurium with A between 112 and 134. The results were analysed using as particles interaction: pairing and SDI (Surface Delta Interaction). The SDI and 3 fonons collective states were used in the fittings, and a syntematic comparison between the theoretical and experimental results was made. The dependence of the results with the model parameters was determined, through large variation sof them. Calculations using 4 fonons have been made, and the importance of the introduced variations in the results was discussed. Calculations have been made in the VAX Computer of the Pelletron at IFUSP. (author) [pt

  7. A geometric measure of dark energy with pairs of galaxies.

    Science.gov (United States)

    Marinoni, Christian; Buzzi, Adeline

    2010-11-25

    Observations indicate that the expansion of the Universe is accelerating, which is attributed to a ‘dark energy’ component that opposes gravity. There is a purely geometric test of the expansion of the Universe (the Alcock–Paczynski test), which would provide an independent way of investigating the abundance (Ω(X)) and equation of state (W(X)) of dark energy. It is based on an analysis of the geometrical distortions expected from comparing the real-space and redshift-space shape of distant cosmic structures, but it has proved difficult to implement. Here we report an analysis of the symmetry properties of distant pairs of galaxies from archival data. This allows us to determine that the Universe is flat. By alternately fixing its spatial geometry at Ω(k)≡0 and the dark energy equation-of-state parameter at W(X)≡-1, and using the results of baryon acoustic oscillations, we can establish at the 68.3% confidence level that and -0.85>W(X)>-1.12 and 0.60<Ω(X)<0.80.

  8. Density and starting-energy dependent effective interaction

    International Nuclear Information System (INIS)

    Yamaguchi, Norio; Nagata, Sinobu; Kasuga, Teruo

    1979-01-01

    A new effective potential constructed from the reaction matrix calculation of nuclear matters is proposed, taking three-body effects into account. Starting from the two-body scattering equation for nuclear matters, an equation with averaged momentum is introduced as the definition of effective interaction. The parameters in the equation are the Fermi momentum and the starting energy. The nuclear density dependence and the starting energy dependence are independently treated in the potential. The effective interactions including three-body effects were calculated. The dependence on the starting energy is large. The effective interaction is more attractive in the triplet E state, and assures overall saturation without any artificial renormalization. The reaction matrix calculation can be well reproduced by the calculation with this effective potential. The results of calculation for the binding energy of He-4 and O-16 and the shell model matrix elements of O-16 are represented. (Kato, T.)

  9. Report of the Interagency Task Force on High Energy Density Physics

    Energy Technology Data Exchange (ETDEWEB)

    None

    2007-08-01

    Identifies the needs for improving Federal stewardship of specific aspects of high energy density physics, particularly the study of high energy density plasmas in the laboratory, and strengthening university activities in this latter discipline. The report articulates how HEDP fits into the portfolio of federally funded missions and includes agency actions to be taken that are necessary to further this area of study consistent with Federal priorities and plans, while being responsive to the needs of the scientific community.

  10. Report of the Interagency Task Force on High Energy Density Physics

    International Nuclear Information System (INIS)

    2007-01-01

    Identifies the needs for improving Federal stewardship of specific aspects of high energy density physics, particularly the study of high energy density plasmas in the laboratory, and strengthening university activities in this latter discipline. The report articulates how HEDP fits into the portfolio of federally funded missions and includes agency actions to be taken that are necessary to further this area of study consistent with Federal priorities and plans, while being responsive to the needs of the scientific community

  11. Wind power statistics and an evaluation of wind energy density

    Energy Technology Data Exchange (ETDEWEB)

    Jamil, M.; Parsa, S.; Majidi, M. [Materials and Energy Research Centre, Tehran (Iran, Islamic Republic of)

    1995-11-01

    In this paper the statistical data of fifty days` wind speed measurements at the MERC- solar site are used to find out the wind energy density and other wind characteristics with the help of the Weibull probability distribution function. It is emphasized that the Weibull and Rayleigh probability functions are useful tools for wind energy density estimation but are not quite appropriate for properly fitting the actual wind data of low mean speed, short-time records. One has to use either the actual wind data (histogram) or look for a better fit by other models of the probability function. (Author)

  12. Nuclear scissors mode with pairing

    International Nuclear Information System (INIS)

    Balbutsev, E. B.; Malov, L. A.; Schuck, P.; Urban, M.; Vinas, X.

    2008-01-01

    The coupled dynamics of the scissors mode and the isovector giant quadrupole resonance are studied using a generalized Wigner function moments method, taking into account pair correlations. Equations of motion for angular momentum, quadrupole moment, and other relevant collective variables are derived on the basis of the time-dependent Hartree-Fock-Bogolyubov equations. Analytical expressions for energy centroids and transition probabilities are found for the harmonic-oscillator model with the quadrupole-quadrupole residual interaction and monopole pairing force. Deformation dependences of energies and B(M1) values are correctly reproduced. The inclusion of pair correlations leads to a drastic improvement in the description of qualitative and quantitative characteristics of the scissors mode.

  13. Solid neutron matter the energy density in the relativistic harmonic approximation

    International Nuclear Information System (INIS)

    Cattani, M.; Fernandes, N.C.

    A relativistic expression for the energy density as a function of particle density for solid neutron matter is obtained using Dirac's equation with a truncated harmonic potential. Ultrabaric and superluminous effects are not found in our approach [pt

  14. Pairing induced superconductivity in holography

    Science.gov (United States)

    Bagrov, Andrey; Meszena, Balazs; Schalm, Koenraad

    2014-09-01

    We study pairing induced superconductivity in large N strongly coupled systems at finite density using holography. In the weakly coupled dual gravitational theory the mechanism is conventional BCS theory. An IR hard wall cut-off is included to ensure that we can controllably address the dynamics of a single confined Fermi surface. We address in detail the interplay between the scalar order parameter field and fermion pairing. Adding an explicitly dynamical scalar operator with the same quantum numbers as the fermion-pair, the theory experiences a BCS/BEC crossover controlled by the relative scaling dimensions. We find the novel result that this BCS/BEC crossover exposes resonances in the canonical expectation value of the scalar operator. This occurs not only when the scaling dimension is degenerate with the Cooper pair, but also with that of higher derivative paired operators. We speculate that a proper definition of the order parameter which takes mixing with these operators into account stays finite nevertheless.

  15. High energy-density science on the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, E.M.; Cauble, R.; Remington, B.A.

    1997-08-01

    The National Ignition Facility, as well as its French counterpart Le Laser Megajoule, have been designed to confront one of the most difficult and compelling problem in shock physics - the creation of a hot, compassed DT plasma surrounded and confined by cold, nearly degenerate DT fuel. At the same time, these laser facilities will present the shock physics community with unique tools for the study of high energy density matter at states unreachable by any other laboratory technique. Here we describe how these lasers can contribute to investigations of high energy density in the area of material properties and equations of state, extend present laboratory shock techniques such as high-speed jets to new regimes, and allow study of extreme conditions found in astrophysical phenomena.

  16. Theoretical study of GC+/GC base pair derivatives

    International Nuclear Information System (INIS)

    Meng Fancui; Wang Huanjie; Xu Weiren; Liu Chengbu

    2005-01-01

    The geometries of R (R=CH 3 , CH 3 O, F, NO 2 ) substituted GC base pair derivatives and their cations have been optimized at B3LYP/6-31G* level and the substituent effects on the neutral and cationic geometric structures and energies have been discussed. The inner reorganization energies of various base pair derivatives and the native GC base pair have been calculated to discuss the substituent effects on the reorganization energy. NBO (natural bond orbital) analysis has been carried out on both the neutral and the cationic systems to investigate the differences of the charge distributions and the electronic structures. The outcomes indicate that 8-CH 3 O-G:C has the greatest reorganization energy and 8-NO 2 -G:C has the least, while the other substituted base pairs have a reorganization energy close to that of G:C. The one charge is mostly localized on guanine part after ionization and as high as 0.95e. The bond distances of N1-N3'andN2-O2' in the cationic base pair derivatives shortened and that of O6-N4' elongated as compared with the corresponding bond distances of the neutral GC base pair derivatives

  17. Level densities of iron isotopes and lower-energy enhancement of y-strength function

    International Nuclear Information System (INIS)

    Voinov, A V; Grimes, S M; Agvaanluvsan, U; Algin, E; Belgya, T; Brune, C R; Guttormsen, M; Hornish, M J; Massey, T N; Mitchell, G; Rekstad, J; Schiller, A; Siem, S

    2005-01-01

    The neutron spectrum from the 55 Mn(d,n) 56 Fe reaction has been measured at E d = 7 MeV. The level density of 56 Fe obtained from neutron evaporation spectrum has been compared to the level density from Oslo-type 57 Fe( 3 He, aγ) 56 Fe experiment [1]. The good agreement supports the recent results [1, 8] including an availability of a low-energy enhancement in the γ-strength function for iron isotopes. The new level density function allowed us to investigate an excitation energy dependence of this enhancement, which is shown to increase with increasing excitation energy

  18. Energy density and rate limitations in structural composite supercapacitors

    Science.gov (United States)

    Snyder, J. F.; Gienger, E.; Wetzel, E. D.; Xu, K.

    2012-06-01

    The weight and volume of conventional energy storage technologies greatly limits their performance in mobile platforms. Traditional research efforts target improvements in energy density to reduce device size and mass. Enabling a device to perform additional functions, such as bearing mechanical load, is an alternative approach as long as the total mass efficiency exceeds that of the individual materials it replaces. Our research focuses on structural composites that function as batteries and supercapacitors. These multifunctional devices could be used to replace conventional structural components, such as vehicle frame elements, to provide significant system-level weight reductions and extend mission times. Our approach is to design structural properties directly into the electrolyte and electrode materials. Solid polymer electrolyte materials bind the system and transfer load to the fibers while conducting ions between the electrodes. Carbon fiber electrodes provide a route towards optimizing both energy storage and load-bearing capabilities, and may also obviate the need for a separate current collector. The components are being integrated using scalable, cost-effective composite processing techniques that are amenable to complex part shapes. Practical considerations of energy density and rate behavior are described here as they relate to materials used. Our results highlight the viability as well as the challenges of this multifunctional approach towards energy storage.

  19. Fluctuations in transverse energy and mulitplicity, energy densities, and neutral pion spectra in nucleus-nucleus collisions at 200 GeV/nucleon

    International Nuclear Information System (INIS)

    1989-01-01

    The main goal of the CERN heavy-ion experiments is the search for an indication that the predicted state of deconfined quarks and gluons, the quark-gluon plasma (QGP), has been produced. The quantity most crucial to the probability of QGP formation is the thermalized energy density attained during the heavy-ion reaction. The amount of energy radiated transverse to the beam direction is the experimental quantity which is believed to be a measure of the amount of energy deposition in the reaction, and hence to reflect the energy density attained. In this presentation we consider the systematics of transverse energy production at CERN SPS energies, and we use the results to make estimates, under various assumptions, of attained energy densities

  20. Vacuum stress energy density and its gravitational implications

    Science.gov (United States)

    Estrada, Ricardo; Fulling, Stephen A.; Kaplan, Lev; Kirsten, Klaus; Liu, Zhonghai; Milton, Kimball A.

    2008-04-01

    In nongravitational physics the local density of energy is often regarded as merely a bookkeeping device; only total energy has an experimental meaning—and it is only modulo a constant term. But in general relativity the local stress-energy tensor is the source term in Einstein's equation. In closed universes, and those with Kaluza-Klein dimensions, theoretical consistency demands that quantum vacuum energy should exist and have gravitational effects, although there are no boundary materials giving rise to that energy by van der Waals interactions. In the lab there are boundaries, and in general the energy density has a nonintegrable singularity as a boundary is approached (for idealized boundary conditions). As pointed out long ago by Candelas and Deutsch, in this situation there is doubt about the viability of the semiclassical Einstein equation. Our goal is to show that the divergences in the linearized Einstein equation can be renormalized to yield a plausible approximation to the finite theory that presumably exists for realistic boundary conditions. For a scalar field with Dirichlet or Neumann boundary conditions inside a rectangular parallelepiped, we have calculated by the method of images all components of the stress tensor, for all values of the conformal coupling parameter and an exponential ultraviolet cutoff parameter. The qualitative features of contributions from various classes of closed classical paths are noted. Then the Estrada-Kanwal distributional theory of asymptotics, particularly the moment expansion, is used to show that the linearized Einstein equation with the stress-energy near a plane boundary as source converges to a consistent theory when the cutoff is removed. This paper reports work in progress on a project combining researchers in Texas, Louisiana and Oklahoma. It is supported by NSF Grants PHY-0554849 and PHY-0554926.

  1. Chemically and Thermally Stable High Energy Density Silicone Composites, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermal energy storage systems with 300 -- 1000 kJ/kg energy density through either phase changes or chemical heat absorption are sought by NASA. This proposed...

  2. Charged-particle multiplicity density at mid-rapidity in central Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV

    CERN Document Server

    Aamodt, K; Abrahantes Quintana, A; Adamova, D; Adare, A M; Aggarwal, M M; Aglieri Rinella, G; Agocs, A G; Aguilar Salazar, S; Ahammed, Z; Ahmad Masoodi, A; Ahmad, N; Ahn, S U; Akindinov, A; Aleksandrov, D; Alessandro, B; Alfaro Molina, R; Alici, A; Alkin, A; Almaraz Avina, E; Alt, T; Altini, V; Altinpinar, S; Altsybeev, I; Andrei, C; Andronic, A; Anguelov, V; Anson, C; Anticic, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshauser, H; Arbor, N; Arcelli, S; Arend, A; Armesto, N; Arnaldi, R; Aronsson, T; Arsene, I C; Asryan, A; Augustinus, A; Averbeck, R; Awes, T C; Aysto, J; Azmi, M D; Bach, M; Badala, A; Baek, Y W; Bagnasco, S; Bailhache, R; Bala, R; Baldini-Ferroli, R; Baldisseri, A; Baldit, A; Baltasar Dos Santos Pedrosa, F; Ban, J; Barbera, R; Barile, F; Barnafoldi, G G; Barnby, L S; Barret, V; Bartke, J; Basile, M; Bastid, N; Bathen, B; Batigne, G; Batyunya, B; Baumann, C; Bearden, I G; Beck, H; Belikov, I; Bellini, F; Bellwied, R; Belmont-Moreno, E; Beole, S; Berceanu, I; Bercuci, A; Berdermann, E; Berdnikov, Y; Bergmann, C; Betev, L; Bhasin, A; Bhati, A K; Bianchi, L; Bianchi, N; Bianchin, C; Bielcik, J; Bielcikova, J; Bilandzic, A; Biolcati, E; Blanc, A; Blanco, F; Blanco, F; Blau, D; Blume, C; Boccioli, M; Bock, N; Bogdanov, A; Boggild, H; Bogolyubsky, M; Boldizsar, L; Bombara, M; Bombonati, C; Book, J; Borel, H; Borissov, A; Bortolin, C; Bose, S; Bossu, F; Botje, M; Bottger, S; Boyer, B; Braun-Munzinger, P; Bravina, L; Bregant, M; Breitner, T; Broz, M; Brun, R; Bruna, E; Bruno, G E; Budnikov, D; Buesching, H; Bugaiev, K; Busch, O; Buthelezi, Z; Caffarri, D; Cai, X; Caines, H; Calvo Villar, E; Camerini, P; Canoa Roman, V; Cara Romeo, G; Carena, F; Carena, W; Carminati, F; Casanova Diaz, A; Caselle, M; Castillo Castellanos, J; Catanescu, V; Cavicchioli, C; Cepila, J; Cerello, P; Chang, B; Chapeland, S; Charvet, J L; Chattopadhyay, S; Chattopadhyay, S; Cherney, M; Cheshkov, C; Cheynis, B; Chiavassa, E; Chibante Barroso, V; Chinellato, D D; Chochula, P; Chojnacki, M; Christakoglou, P; Christensen, C H; Christiansen, P; Chujo, T; Cicalo, C; Cifarelli, L; Cindolo, F; Cleymans, J; Coccetti, F; Coffin, J P; Coli, S; Conesa Balbastre, G; Conesa del Valle, Z; Constantin, P; Contin, G; Contreras, J G; Cormier, T M; Corrales Morales, Y; Cortes Maldonado, I; Cortese, P; Cosentino, M R; Costa, F; Cotallo, M E; Crescio, E; Crochet, P; Cuautle, E; Cunqueiro, L; D'Erasmo, G; Dainese, A; Dalsgaard, H H; Danu, A; Das, D; Das, I; Das, K; Dash, A; Dash, S; De, S; De Azevedo Moregula, A; de Barros, G O V; De Caro, A; de Cataldo, G; de Cuveland, J; De Falco, A; De Gruttola, D; De Marco, N; De Pasquale, S; De Remigis, R; de Rooij, R; Debski, P R; Del Castillo Sanchez, E; Delagrange, H; Delgado Mercado, Y; Dellacasa, G; Deloff, A; Demanov, V; Denes, E; Deppman, A; Di Bari, D; Di Giglio, C; Di Liberto, S; Di Mauro, A; Di Nezza, P; Dietel, T; Divia, R; Djuvsland, O; Dobrin, A; Dobrowolski, T; Dominguez, I; Donigus, B; Dordic, O; Driga, O; Dubey, A K; Dubuisson, J; Ducroux, L; Dupieux, P; Dutta Majumdar, A K; Dutta Majumdar, M R; Elia, D; Emschermann, D; Engel, H; Erdal, H A; Espagnon, B; Estienne, M; Esumi, S; Evans, D; Evrard, S; Eyyubova, G; Fabjan, C W; Fabris, D; Faivre, J; Falchieri, D; Fantoni, A; Fasel, M; Fearick, R; Fedunov, A; Fehlker, D; Fekete, V; Felea, D; Feofilov, G; Fernandez Tellez, A; Ferretti, A; Ferretti, R; Figiel, J; Figueredo, M A S; Filchagin, S; Fini, R; Finogeev, D; Fionda, F M; Fiore, E M; Floris, M; Foertsch, S; Foka, P; Fokin, S; Fragiacomo, E; Fragkiadakis, M; Frankenfeld, U; Fuchs, U; Furano, F; Furget, C; Fusco Girard, M; Gaardhoje, J J; Gadrat, S; Gagliardi, M; Gago, A; Gallio, M; Gangadharan, D R; Ganoti, P; Ganti, M S; Garabatos, C; Garcia-Solis, E; Garishvili, I; Gemme, R; Gerhard, J; Germain, M; Geuna, C; Gheata, A; Gheata, M; Ghidini, B; Ghosh, P; Gianotti, P; Girard, M R; Giraudo, G; Giubellino, P; Gladysz-Dziadus, E; Glassel, P; Gomez, R; Ferreiro, E G; Gonzalez Santos, H; González-Trueba, L H; González-Zamora, P; Gorbunov, S; Gotovac, S; Grabski, V; Grajcarek, R; Grelli, A; Grigoras, A; Grigoras, C; Grigoriev, V; Grigoryan, A; Grigoryan, S; Grinyov, B; Grion, N; Gros, P; Grosse-Oetringhaus, J F; Grossiord, J Y; Grosso, R; Guber, F; Guernane, R; Guerra Gutierrez, C; Guerzoni, B; Gulbrandsen, K; Gunji, T; Gupta, A; Gupta, R; Gutbrod, H; Haaland, O; Hadjidakis, C; Haiduc, M; Hamagaki, H; Hamar, G; Harris, J W; Hartig, M; Hasch, D; Hasegan, D; Hatzifotiadou, D; Hayrapetyan, A; Heide, M; Heinz, M; Helstrup, H; Herghelegiu, A; Hernandez, C; Herrera Corral, G; Herrmann, N; Hetland, K F; Hicks, B; Hille, P T; Hippolyte, B; Horaguchi, T; Hori, Y; Hristov, P; Hrivnacova, I; Huang, M; Huber, S; Humanic, T J; Hwang, D S; Ichou, R; Ilkaev, R; Ilkiv, I; Inaba, M; Incani, E; Innocenti, G M; Innocenti, P G; Ippolitov, M; Irfan, M; Ivan, C; Ivanov, A; Ivanov, M; Ivanov, V; Jacholkowski, A; Jacobs, P M; Jancurova, L; Jangal, S; Janik, R; Jena, S; Jirden, L; Jones, G T; Jones, P G; Jovanovic, P; Jung, H; Jung, W; Jusko, A; Kalcher, S; Kalinak, P; Kalisky, M; Kalliokoski, T; Kalweit, A; Kamermans, R; Kanaki, K; Kang, E; Kang, J H; Kaplin, V; Karavichev, O; Karavicheva, T; Karpechev, E; Kazantsev, A; Kebschull, U; Keidel, R; Khan, M M; Khan, S A; Khanzadeev, A; Kharlov, Y; Kileng, B; Kim, D J; Kim, D S; Kim, D W; Kim, H N; Kim, J H; Kim, J S; Kim, M; Kim, M; Kim, S; Kim, S H; Kirsch, S; Kisel, I; Kiselev, S; Kisiel, A; Klay, J L; Klein, J; Klein-Bosing, C; Kliemant, M; Klovning, A; Kluge, A; Knichel, M L; Koch, K; Kohler, M; Kolevatov, R; Kolojvari, A; Kondratiev, V; Kondratyeva, N; Konevskih, A; Kornas, E; Kottachchi Kankanamge Don, C; Kour, R; Kowalski, M; Kox, S; Koyithatta Meethaleveedu, G; Kozlov, K; Kral, J; Kralik, I; Kramer, F; Kraus, I; Krawutschke, T; Kretz, M; Krivda, M; Krizek, F; Krumbhorn, D; Krus, M; Kryshen, E; Krzewicki, M; Kucheriaev, Y; Kuhn, C; Kuijer, P G; Kurashvili, P; Kurepin, A; Kurepin, A B; Kuryakin, A; Kushpil, S; Kushpil, V; Kweon, M J; Kwon, Y; La Rocca, P; Ladron de Guevara, P; Lafage, V; Lara, C; Lardeux, A; Larsen, D T; Lazzeroni, C; Le Bornec, Y; Lea, R; Lee, K S; Lee, S C; Lefevre, F; Lehnert, J; Leistam, L; Lenhardt, M; Lenti, V; Leon Monzon, I; Leon Vargas, H; Levai, P; Li, X; Lien, J; Lietava, R; Lindal, S; Lindenstruth, V; Lippmann, C; Lisa, M A; Liu, L; Loenne, P I; Loggins, V R; Loginov, V; Lohn, S; Loizides, C; Loo, K K; Lopez, X; Lopez Noriega, M; Lopez Torres, E; Lovhoiden, G; Lu, X G; Luettig, P; Lunardon, M; Luparello, G; Luquin, L; Luzzi, C; Ma, K; Ma, R; Madagodahettige-Don, D M; Maevskaya, A; Mager, M; Mahapatra, D P; Maire, A; Mal'Kevich, D; Malaev, M; Maldonado Cervantes, I; Malinina, L; Malzacher, P; Mamonov, A; Manceau, L; Mangotra, L; Manko, V; Manso, F; Manzari, V; Mao, Y; Mares, J; Margagliotti, G V; Margotti, A; Marin, A; Markert, C; Martashvili, I; Martinengo, P; Martinez, M I; Martinez Davalos, A; Martinez Garcia, G; Martynov, Y; Masciocchi, S; Masera, M; Masoni, A; Massacrier, L; Mastromarco, M; Mastroserio, A; Matthews, Z L; Matyja, A; Mayani, D; Mayer, C; Mazza, G; Mazzoni, M A; Meddi, F; Menchaca-Rocha, A; Mendez Lorenzo, P; Menis, I; Mercado Perez, J; Meres, M; Mereu, P; Miake, Y; Midori, J; Milano, L; Milosevic, J; Mischke, A; Miskowiec, D; Mitu, C; Mlynarz, J; Mohanty, A K; Mohanty, B; Molnar, L; Montano Zetina, L; Monteno, M; Montes, E; Morando, M; Moreira De Godoy, D A; Moretto, S; Morsch, A; Muccifora, V; Mudnic, E; Muhuri, S; Muller, H; Munhoz, M G; Munoz, J; Musa, L; Musso, A; Nandi, B K; Nania, R; Nappi, E; Nattrass, C; Navach, F; Navin, S; Nayak, T K; Nazarenko, S; Nazarov, G; Nedosekin, A; Nendaz, F; Newby, J; Nicassio, M; Nielsen, B S; Niida, T; Nikolaev, S; Nikolic, V; Nikulin, S; Nikulin, V; Nilsen, B S; Nilsson, M S; Noferini, F; Nooren, G; Novitzky, N; Nyanin, A; Nyatha, A; Nygaard, C; Nystrand, J; Obayashi, H; Ochirov, A; Oeschler, H; Oh, S K; Oleniacz, J; Oppedisano, C; Ortiz Velasquez, A; Ortona, G; Oskarsson, A; Ostrowski, P; Otterlund, I; Otwinowski, J; Oyama, K; Ozawa, K; Pachmayer, Y; Pachr, M; Padilla, F; Pagano, P; Jayarathna, S P; Paic, G; Painke, F; Pajares, C; Pal, S; Pal, S K; Palaha, A; Palmeri, A; Pappalardo, G S; Park, W J; Patalakha, D I; Paticchio, V; Pavlinov, A; Pawlak, T; Peitzmann, T; Peresunko, D; Perez Lara, C E; Perini, D; Perrino, D; Peryt, W; Pesci, A; Peskov, V; Pestov, Y; Peters, A J; Petracek, V; Petran, M; Petris, M; Petrov, P; Petrovici, M; Petta, C; Piano, S; Piccotti, A; Pikna, M; Pillot, P; Pinazza, O; Pinsky, L; Pitz, N; Piuz, F; Piyarathna, D B; Platt, R; Ploskon, M; Pluta, J; Pocheptsov, T; Pochybova, S; Podesta-Lerma, P L M; Poghosyan, M G; Polak, K; Polichtchouk, B; Pop, A; Porteboeuf, S; Pospisil, V; Potukuchi, B; Prasad, S K; Preghenella, R; Prino, F; Pruneau, C A; Pshenichnov, I; Puddu, G; Pulvirenti, A; Punin, V; Putis, M; Putschke, J; Quercigh, E; Qvigstad, H; Rachevski, A; Rademakers, A; Rademakers, O; Radomski, S; Raiha, T S; Rak, J; Rakotozafindrabe, A; Ramello, L; Ramirez Reyes, A; Rammler, M; Raniwala, R; Raniwala, S; Rasanen, S S; Read, K F; Real, J; Redlich, K; Renfordt, R; Reolon, A R; Reshetin, A; Rettig, F; Revol, J P; Reygers, K; Ricaud, H; Riccati, L; Ricci, R A; Richter, M; Riedler, P; Riegler, W; Riggi, F; Rodriguez Cahuantzi, M; Rohr, D; Rohrich, D; Romita, R; Ronchetti, F; Rosinsky, P; Rosnet, P; Rossegger, S; Rossi, A; Roukoutakis, F; Rousseau, S; Roy, C; Roy, P; Rubio Montero, A J; Rui, R; Rivetti, A; Rusanov, I; Ryabinkin, E; Rybicki, A; Sadovsky, S; Safarik, K; Sahoo, R; Sahu, P K; Saini, J; Saiz, P; Sakai, S; Sakata, D; Salgado, C A; Samanta, T; Sambyal, S; Samsonov, V; Sanchez Castro, X; Sandor, L; Sandoval, A; Sano, M; Sano, S; Santo, R; Santoro, R; Sarkamo, J; Saturnini, P; Scapparone, E; Scarlassara, F; Scharenberg, R P; Schiaua, C; Schicker, R; Schmidt, C; Schmidt, H R; Schreiner, S; Schuchmann, S; Schukraft, J; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, P A; Scott, R; Segato, G; Selyuzhenkov, I; Senyukov, S; Seo, J; Serci, S; Serradilla, E; Sevcenco, A; Sgura, I; Shabratova, G; Shahoyan, R; Sharma, N; Sharma, S; Shigaki, K; Shimomura, M; Shtejer, K; Sibiriak, Y; Siciliano, M; Sicking, E; Siemiarczuk, T; Silenzi, A; Silvermyr, D; Simonetti, G; Singaraju, R; Singh, R; Singhal, V; Sinha, B C; Sinha, T; Sitar, B; Sitta, M; Skaali, T B; Skjerdal, K; Smakal, R; Smirnov, N; Snellings, R; Sogaard, C; Soloviev, A; Soltz, R; Son, H; Song, J; Song, M; Soos, C; Soramel, F; Spyropoulou-Stassinaki, M; Srivastava, B K; Stachel, J; Stan, I; Stefanek, G; Stefanini, G; Steinbeck, T; Steinpreis, M; Stenlund, E; Steyn, G; Stocco, D; Stock, R; Stokkevag, C H; Stolpovskiy, M; Strmen, P; Suaide, A A P; Subieta Vasquez, M A; Sugitate, T; Suire, C; Sukhorukov, M; Sumbera, M; Susa, T; Swoboda, D; Symons, T J M; Szanto de Toledo, A; Szarka, I; Szostak, A; Tagridis, C; Takahashi, J; Tapia Takaki, J D; Tauro, A; Tavlet, M; Tejeda Munoz, G; Telesca, A; Terrevoli, C; Thader, J; Thomas, D; Thomas, J H; Tieulent, R; Timmins, A R; Tlusty, D; Toia, A; Torii, H; Toscano, L; Tosello, F; Traczyk, T; Truesdale, D; Trzaska, W H; Tsuji, T; Tumkin, A; Turrisi, R; Turvey, A J; Tveter, T S; Ulery, J; Ullaland, K; Uras, A; Urban, J; Urciuoli, G M; Usai, G L; Vacchi, A; Vajzer, M; Vala, M; Valencia Palomo, L; Vallero, S; van der Kolk, N; van Leeuwen, M; Vande Vyvre, P; Vannucci, L; Vargas, A; Varma, R; Vasileiou, M; Vasiliev, A; Vechernin, V; Veldhoen, M; Venaruzzo, M; Vercellin, E; Vergara, S; Vernekohl, D C; Vernet, R; Verweij, M; Vickovic, L; Viesti, G; Vikhlyantsev, O; Vilakazi, Z; Villalobos Baillie, O; Vinogradov, A; Vinogradov, L; Vinogradov, Y; Virgili, T; Viyogi, Y P; Vodopyanov, A; Voloshin, K; Voloshin, S; Volpe, G; von Haller, B; Vranic, D; Ovrebekk, G; Vrlakova, J; Vulpescu, B; Vyushin, A; Wagner, B; Wagner, V; Wan, R; Wang, D; Wang, Y; Wang, Y; Watanabe, K; Wessels, J P; Westerhoff, U; Wiechula, J; Wikne, J; Wilde, M; Wilk, A; Wilk, G; Williams, M C S; Windelband, B; Xaplanteris Karampatsos, L; Yang, H; Yang, S; Yasnopolskiy, S; Yi, J; Yin, Z; Yokoyama, H; Yoo, I K; Yu, W; Yuan, X; Yushmanov, I; Zabrodin, E; Zach, C; Zampolli, C; Zaporozhets, S; Zarochentsev, A; Zavada, P; Zaviyalov, N; Zbroszczyk, H; Zelnicek, P; Zenin, A; Zgura, I; Zhalov, M; Zhang, X; Zhou, D; Zichichi, A; Zinovjev, G; Zoccarato, Y; Zynovyev, M

    2010-01-01

    The first measurement of the charged-particle multiplicity density at mid-rapidity in Pb-Pb collisions at a centre-of-mass energy per nucleon pair sqrt(sNN) = 2.76 TeV is presented. For an event sample corresponding to the most central 5% of the hadronic cross section the pseudo-rapidity density of primary charged particles at mid-rapidity is 1584 +- 4 (stat) +- 76 (sys.), which corresponds to 8.3 +- 0.4 (sys.) per participating nucleon pair. This represents an increase of about a factor 1.9 relative to pp collisions at similar collision energies, and about a factor 2.2 to central Au-Au collisions at sqrt(sNN) = 0.2 TeV. This measurement provides the first experimental constraint for models of nucleus-nucleus collisions at LHC energies.

  3. Double-layer capacitors with a higher energy density; Doppelschichtkondensatoren mit hoeherem Energieinhalt

    Energy Technology Data Exchange (ETDEWEB)

    Presser, Volker [Leibniz-Institut fuer Neue Materialien (INM) gGmbH, Saarbruecken (Germany). Juniorforschungs-Gruppe Energie-Materialien; Universitaet des Saarlandes, Saarbruecken (Germany)

    2013-05-15

    Electrical double-layer capacitors, also known as supercapacitors (SC) are devices for electrical energy storage used for fast acceleration of hybrid cars or for the energy recovery during breaking operations. In contrast, lithium-ion batteries (LIB) are used as energy storage devices to provide an extended travel distance for plug-in hybrid cars and electric vehicles. Current research aims to overcome the major limitations of both technologies (SC: low energy density/LIB: slow recharge and limited service life) and hybrid cells are considered a promising solution. The goal is to improve the performance and energy density of storage devices which can be achieved, as shown by the Leibniz-Institute for New Materials (INM), with the use of nanotechnology. (orig.)

  4. Modelling of the energy density deposition profiles of ultrashort laser pulses focused in optical media

    International Nuclear Information System (INIS)

    Vidal, F; Lavertu, P-L; Bigaouette, N; Moore, F; Brunette, I; Giguere, D; Kieffer, J-C; Olivie, G; Ozaki, T

    2007-01-01

    The propagation of ultrashort laser pulses in dense optical media is investigated theoretically by solving numerically the nonlinear Schroedinger equation. It is shown that the maximum energy density deposition as a function of the pulse energy presents a well-defined threshold that increases with the pulse duration. As a consequence of plasma defocusing, the maximum energy density deposition is generally smaller and the size of the energy deposition zone is generally larger for shorter pulses. Nevertheless, significant values of the energy density deposition can be obtained near threshold, i.e., at lower energy than for longer pulses

  5. Simulations of the azimuthal distribution of low-energy H atoms scattered off Ag(1 1 0) at grazing incidence: DFT many-body versus model pair potentials

    CERN Document Server

    Cafarelli, P; Benazeth, C; Nieuwjaer, N; Lorente, N

    2003-01-01

    We compare the azimuthal distribution of H atoms after scattering off Ag(1 1 0) obtained by molecular dynamics with different H-Ag(1 1 0) potential energy surfaces (PES) and experimental results. We use grazing incident H atoms and low energies (up to 4 keV). Density functional theory (DFT) calculations are performed for the static case of an H atom in front of an Ag(1 1 0) surface. The surface is represented by an 8-atom slab, and the H atoms form 1x1 and 2x2 supercells. The generalized gradient approximation is used. Classical trajectories are evaluated on the obtained PES, and the azimuthal distribution of the scattered atoms is calculated. Good agreement with experiment is obtained which gives us some confidence in the correct description of the system at low energies by the static DFT calculations. These results are also compared with pair-potential calculations. The accuracy of trajectories may be important for the correct evaluation of charge transfer, energy loss and straggling during ion-surface coll...

  6. Tantalum surface oxidation: Bond relaxation, energy entrapment, and electron polarization

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yongling [Key Laboratory of Low-Dimensional Materials and Application Technologies (Ministry of Education), Hunan Provincial Key Laboratory of Thin Film Materials and Devices, Faculty of Materials Science and Engineering, Xiangtan University, Hunan 411105 (China); Bo, Maolin [Yangtze Normal University, College of Mechanical and Electrical Engineering, Chongqing 408100 (China); Wang, Yan [School of Information and Electronic Engineering, Hunan University of Science and Technology, Hunan 411201 (China); Liu, Yonghui [Key Laboratory of Low-Dimensional Materials and Application Technologies (Ministry of Education), Hunan Provincial Key Laboratory of Thin Film Materials and Devices, Faculty of Materials Science and Engineering, Xiangtan University, Hunan 411105 (China); Sun, Chang Q. [NOVITAS, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Huang, Yongli, E-mail: huangyongli@xtu.edu.cn [Key Laboratory of Low-Dimensional Materials and Application Technologies (Ministry of Education), Hunan Provincial Key Laboratory of Thin Film Materials and Devices, Faculty of Materials Science and Engineering, Xiangtan University, Hunan 411105 (China)

    2017-02-28

    Graphical abstract: The bond, electron and energy relaxation result in core level energy shift, local densification, quantum entrapment and electron polarization of bonding electrons. - Highlights: • Increasing the oxygen coverage lowers the adsorption energy associated with lattice reconstruction. • Electrons transfer from Ta surface atoms to sp-hydrated oxygen, creating dipole moment that decreases the work function. • Oxygen chemisorption modified valence density-of-state (DOS) for Ta with four excessive DOS features: O−Ta bonding, O{sup 2−} lone pairs, Ta+ electron holes, and the lone-pair polarized Ta dipoles. • The bond, electron and energy relaxation between surface undercoordinated atoms are responsible for core level energy shift, local densification, quantum entrapment and electron polarization of bonding electrons. - Abstract: A combination of photoelectron spectrometric analysis and density functional theory calculations has enabled reconciliation of the bond-energy-electron relaxation for the Ta(100, 110, 111) surfaces chemisorbed with oxygen at different coverages. Results show that increasing oxygen coverage lowers the adsorption energy associated with lattice reconstruction. Valence electrons transfer from Ta surface atoms to oxygen to create four excessive DOS features in terms of O−Ta bonding, lone pairs of oxygen, Ta{sup +} electron holes, and polarized Ta dipoles. Oxidation proceeds in the following dynamics: oxygen gets electrons from two neighboring Ta atoms left behind Ta{sup +}; the sp{sup 3}-orbital hybridization takes place with additional two electron lone pairs, the lone pairs polarize the other two Ta neighbors becoming dipoles. X-ray photoelectron spectral analysis results in the 4f binding energy of an isolated Ta atom and its shift upon bond formation and oxidation. Exercises provide not only a promising numerical approach for the quantitative information about the bond and electronic behavior but also consistent

  7. Tantalum surface oxidation: Bond relaxation, energy entrapment, and electron polarization

    International Nuclear Information System (INIS)

    Guo, Yongling; Bo, Maolin; Wang, Yan; Liu, Yonghui; Sun, Chang Q.; Huang, Yongli

    2017-01-01

    Graphical abstract: The bond, electron and energy relaxation result in core level energy shift, local densification, quantum entrapment and electron polarization of bonding electrons. - Highlights: • Increasing the oxygen coverage lowers the adsorption energy associated with lattice reconstruction. • Electrons transfer from Ta surface atoms to sp-hydrated oxygen, creating dipole moment that decreases the work function. • Oxygen chemisorption modified valence density-of-state (DOS) for Ta with four excessive DOS features: O−Ta bonding, O"2"− lone pairs, Ta+ electron holes, and the lone-pair polarized Ta dipoles. • The bond, electron and energy relaxation between surface undercoordinated atoms are responsible for core level energy shift, local densification, quantum entrapment and electron polarization of bonding electrons. - Abstract: A combination of photoelectron spectrometric analysis and density functional theory calculations has enabled reconciliation of the bond-energy-electron relaxation for the Ta(100, 110, 111) surfaces chemisorbed with oxygen at different coverages. Results show that increasing oxygen coverage lowers the adsorption energy associated with lattice reconstruction. Valence electrons transfer from Ta surface atoms to oxygen to create four excessive DOS features in terms of O−Ta bonding, lone pairs of oxygen, Ta"+ electron holes, and polarized Ta dipoles. Oxidation proceeds in the following dynamics: oxygen gets electrons from two neighboring Ta atoms left behind Ta"+; the sp"3-orbital hybridization takes place with additional two electron lone pairs, the lone pairs polarize the other two Ta neighbors becoming dipoles. X-ray photoelectron spectral analysis results in the 4f binding energy of an isolated Ta atom and its shift upon bond formation and oxidation. Exercises provide not only a promising numerical approach for the quantitative information about the bond and electronic behavior but also consistent insight into the

  8. Perspectives on High-Energy-Density Physics

    Science.gov (United States)

    Drake, R. Paul

    2008-11-01

    Much of 21st century plasma physics will involve work to produce, understand, control, and exploit very non-traditional plasmas. High-energy density (HED) plasmas are often examples, variously involving strong Coulomb interactions and few particles per Debeye sphere, dominant radiation effects, strongly relativistic effects, or strongly quantum-mechanical behavior. Indeed, these and other modern plasma systems often fall outside the early standard theoretical definitions of ``plasma''. This presentation will focus on two types of HED plasmas that exhibit non-traditional behavior. Our first example will be the plasmas produced by extremely strong shock waves. Shock waves are present across the entire realm of plasma densities, often in space or astrophysical contexts. HED shock waves (at pressures > 1 Mbar) enable studies in many areas, from equations of state to hydrodynamics to radiation hydrodynamics. We will specifically consider strongly radiative shocks, in which the radiative energy fluxes are comparable to the mechanical energy fluxes that drive the shocks. Modern HED facilities can produce such shocks, which are also present in dense, energetic, astrophysical systems such as supernovae. These shocks are also excellent targets for advanced simulations due to their range of spatial scales and complex radiation transport. Our second example will be relativistic plasmas. In general, these vary from plasmas containing relativistic particle beams, produced for some decades in the laboratory, to the relativistic thermal plasmas present for example in pulsar winds. Laboratory HED relativistic plasmas to date have been those produced by laser beams of irradiance ˜ 10^18 to 10^22 W/cm^2 or by accelerator-produced HED electron beams. These have applications ranging from generation of intense x-rays to production of proton beams for radiation therapy to acceleration of electrons. Here we will focus on electron acceleration, a spectacular recent success and a rare

  9. Effects of disorder on the electron pairing

    International Nuclear Information System (INIS)

    Oviedo-Roa, R.; Wang, C.; Navarro, O.

    1996-01-01

    The electron pairing in randomly disordered lattices is studied by using an attractive Hubbard model, and by mapping the many-body problem onto a tight-binding one in a higher dimensional space, where a diagonal disorder is considered within the coherent-potential approximation. The results show an enhancement of the pair-binding energy as the self-energy difference increases in a binary alloy A x B 1-x . This fact suggests that the pairing process is highly sensitive to the one-particle localization condition. A ground-state phase diagram for on-site interaction disorder shows regions where pairing is avoided for ordered diatomic systems but not for disordered case

  10. Indirect Measurement of Energy Density of Soft PZT Ceramic Utilizing Mechanical Stress

    Science.gov (United States)

    Unruan, Muangjai; Unruan, Sujitra; Inkong, Yutthapong; Yimnirun, Rattikorn

    2017-11-01

    This paper reports on an indirect measurement of energy density of soft PZT ceramic utilizing mechanical stress. The method works analogous to the Olsen cycle and allows for a large amount of electro-mechanical energy conversion. A maximum energy density of 350 kJ/m3/cycle was found under 0-312 MPa and 1-20 kV/cm of applied mechanical stress and electric field, respectively. The obtained result is substantially higher than the results reported in previous studies of PZT materials utilizing a direct piezoelectric effect.

  11. Coherent and non-coherent double diffractive production of QQ-bar-pairs in collisions of heavy ions at high energies

    International Nuclear Information System (INIS)

    Agababyan, N.M.; Galoyan, A.S.; Enkovskij, L.L.; Zarubin, P.I.; Malakhov, A.I.; Melkumov, G.L.; Chatrchyan, S.A.

    1999-01-01

    The double coherent and non-coherent diffractive production of heavy quark-antiquark pairs (QQ-bar) in heavy ion scattering at high energies (LHC) is considered. The total and differential cross sections of these processes with the formation of cc-bar and bb-bar pairs in pp, CaCa and PbPb collisions are evaluated. The contribution of the considered mechanisms is a few per cent of the number of heavy quark-antiquark pairs obtained in the processes of hard (QCD) scattering, and it will be taken into account in the registration of c, b quarks or, for instance, in the study of the heavy quarkonia suppression effect in Quark-Gluon Plasma, in the search got intermediate mass Higgs bosons and so on. It is shown that the cross section of the coherently scattering process is great enough. This makes it suitable for studying collective effects in nuclear interactions at high energies. An example of such effects is given: large values of the invariant mass of a QQ-bar pair, M QQ-bar ≥ 100 GeV, in association with a large rapidity gap between diffractive jets Δη >5 [ru

  12. Coherent and non-coherent double diffractive production of QQ-bar - pairs in collisions of heavy ions at high energies

    International Nuclear Information System (INIS)

    Agababyan, N.M.; Chatrchyan, S.A.; Galoyan, A.S.; Malakhov, A.I.; Melkumov, G.L.; Zarubin, P.I.; Jenkovszky, L.L.

    1998-01-01

    The double coherent and non-coherent diffractive production of heavy quark-antiquark pair (QQ-bar) in heavy ion scattering at high energies (LHC) is considered. The total and differential cross sections of these processes with the formation of cc bar and bb bar pairs in pp, CaCa and PbPb collisions are evaluated. The contribution of the considered mechanisms is a few per cent of the number of heavy quark-antiquark pairs obtained in the processes of hard (QCD) scattering, and it will be taken into account in the registration of c, b quarks or, for instance, in the study of the heavy quarkonia suppression effects in quark-gluon plasma, in the search for intermediate mass Higgs bosons and so on. It is shown that the cross section of the coherent scattering process is great enough. This makes it suitable for studying collective effects in nuclear interactions at high energies. An example of such effects is given: large values of the invariant mass of a QQ- bar pair, M QQb ar ≥ 100 GeV, in association with a large rapidity gap between diffractive jets Δη>5

  13. The symmetry energy at suprasaturation density and the ASY-EOS experiment at GSI

    Directory of Open Access Journals (Sweden)

    De Filippo E.

    2017-01-01

    Full Text Available The ASY-EOS experiment at GSI laboratory measured the direct and elliptic flow of neutrons and light charged particles in the reaction 197Au+197 Au at 400 A MeV incident energy. The ratio of elliptic flow of neutrons with respect to that of the light charged particles was used as main experimental observable to probe the density dependence of the symmetry energy term of the nuclear equation of state. Results, obtained by comparison of the experimental data with the UrQMD model predictions, strongly support a moderately soft to linear density dependence of the symmetry energy at suprasaturation densities below 2ρ0.

  14. Method for controlling low-energy high current density electron beams

    International Nuclear Information System (INIS)

    Lee, J.N.; Oswald, R.B. Jr.

    1977-01-01

    A method and an apparatus for controlling the angle of incidence of low-energy, high current density electron beams are disclosed. The apparatus includes a current generating diode arrangement with a mesh anode for producing a drifting electron beam. An auxiliary grounded screen electrode is placed between the anode and a target for controlling the average angle of incidence of electrons in the drifting electron beam. According to the method of the present invention, movement of the auxiliary screen electrode relative to the target and the anode permits reliable and reproducible adjustment of the average angle of incidence of the electrons in low energy, high current density relativistic electron beams

  15. US Heavy Ion Beam Research for Energy Density Physics Applications and Fusion

    International Nuclear Information System (INIS)

    Davidson, R.C.; Logan, B.G.; Barnard, J.J.; Bieniosek, F.M.; Briggs, R.J.; Callahan D.A.; Kireeff Covo, M.; Celata, C.M.; Cohen, R.H.; Coleman, J.E.; Debonnel, C.S.; Grote, D.P.; Efthimiom, P.C.; Eylon, S.; Friedman, A.; Gilson, E.P.; Grisham, L.R.; Henestroza, E.; Kaganovich, I.D.; Kwan, J.W.; Lee, E.P.; Lee, W.W.; Leitner, M.; Lund, S.M.; Meier, W.R.; Molvik, A.W.; Olson, C.L.; Penn, G.E.; Qin, H.; Roy, P.K.; Rose, D.V.; Sefkow, A.; Seidl, P.A.; Sharp, W.M.; Startsev, E.A.; Tabak, M.; Thoma, C.; Vay, J-L; Wadron, W.L.; Wurtele, J.S.; Welch, D.R.; Westenskow, G.A.; Yu, S.S.

    2005-01-01

    Key scientific results from recent experiments, modeling tools, and heavy ion accelerator research are summarized that explore ways to investigate the properties of high energy density matter in heavy-ion-driven targets, in particular, strongly-coupled plasmas at 0.01 to 0.1 times solid density for studies of warm dense matter, which is a frontier area in high energy density physics. Pursuit of these near-term objectives has resulted in many innovations that will ultimately benefit heavy ion inertial fusion energy. These include: neutralized ion beam compression and focusing, which hold the promise of greatly improving the stage between the accelerator and the target chamber in a fusion power plant; and the Pulse Line Ion Accelerator (PLIA), which may lead to compact, low-cost modular linac drivers

  16. Exploration of Plasma Jets Approach to High Energy Density Physics. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chiping [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2013-08-26

    High-energy-density laboratory plasma (HEDLP) physics is an emerging, important area of research in plasma physics, nuclear physics, astrophysics, and particle acceleration. While the HEDLP regime occurs at extreme conditions which are often found naturally in space but not on the earth, it may be accessible by colliding high intensity plasmas such as high-energy-density plasma jets, plasmoids or compact toroids from plasma guns. The physics of plasma jets is investigated in the context of high energy density laboratory plasma research. This report summarizes results of theoretical and computational investigation of a plasma jet undergoing adiabatic compression and adiabatic expansion. A root-mean-squared (rms) envelope theory of plasma jets is developed. Comparison between theory and experiment is made. Good agreement between theory and experiment is found.

  17. Free energy landscape and transition pathways from Watson-Crick to Hoogsteen base pairing in free duplex DNA.

    Science.gov (United States)

    Yang, Changwon; Kim, Eunae; Pak, Youngshang

    2015-09-18

    Houghton (HG) base pairing plays a central role in the DNA binding of proteins and small ligands. Probing detailed transition mechanism from Watson-Crick (WC) to HG base pair (bp) formation in duplex DNAs is of fundamental importance in terms of revealing intrinsic functions of double helical DNAs beyond their sequence determined functions. We investigated a free energy landscape of a free B-DNA with an adenosine-thymine (A-T) rich sequence to probe its conformational transition pathways from WC to HG base pairing. The free energy landscape was computed with a state-of-art two-dimensional umbrella molecular dynamics simulation at the all-atom level. The present simulation showed that in an isolated duplex DNA, the spontaneous transition from WC to HG bp takes place via multiple pathways. Notably, base flipping into the major and minor grooves was found to play an important role in forming these multiple transition pathways. This finding suggests that naked B-DNA under normal conditions has an inherent ability to form HG bps via spontaneous base opening events. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  18. Shell and pairing effects in spherical nuclei close to the nucleon drip lines

    International Nuclear Information System (INIS)

    Beiner, M.; Lombard, R.J.

    1975-01-01

    The unstability against nucleon emission of light and medium exotic spherical nuclei is investigated systematically using an extended version of the energy density formalism which reproduces correctly shell and pairing effects in stable nuclei. The reliability of the predictions of this microscopic, self-consistent and weakly parametrized model should not decrease significantly with the distance of the nuclei from the β-stability line, what is not the case for conventional mass formulae or mass tables [fr

  19. Quantification of breast density using dual-energy mammography with liquid phantom calibration

    International Nuclear Information System (INIS)

    Lam, Alfonso R; Ding, Huanjun; Molloi, Sabee

    2014-01-01

    Breast density is a widely recognized potential risk factor for breast cancer. However, accurate quantification of breast density is a challenging task in mammography. The current use of plastic breast-equivalent phantoms for calibration provides limited accuracy in dual-energy mammography due to the chemical composition of the phantom. We implemented a breast-equivalent liquid phantom for dual-energy calibration in order to improve the accuracy of breast density measurement. To design these phantoms, three liquid compounds were chosen: water, isopropyl alcohol, and glycerol. Chemical compositions of glandular and adipose tissues, obtained from NIST database, were used as reference materials. Dual-energy signal of the liquid phantom at different breast densities (0% to 100%) and thicknesses (1 to 8 cm) were simulated. Glandular and adipose tissue thicknesses were estimated from a higher order polynomial of the signals. Our results indicated that the linear attenuation coefficients of the breast-equivalent liquid phantoms match those of the target material. Comparison between measured and known breast density data shows a linear correlation with a slope close to 1 and a non-zero intercept of 7%, while plastic phantoms showed a slope of 0.6 and a non-zero intercept of 8%. Breast density results derived from the liquid calibration phantoms showed higher accuracy than those derived from the plastic phantoms for different breast thicknesses and various tube voltages. We performed experimental phantom studies using liquid phantoms and then compared the computed breast density with those obtained using a bovine tissue model. The experimental data and the known values were in good correlation with a slope close to 1 (∼1.1). In conclusion, our results indicate that liquid phantoms are a reliable alternative for calibration in dual-energy mammography and better reproduce the chemical properties of the target material. (paper)

  20. Energy and nutrient density of foods in relation to their carbon footprint.

    Science.gov (United States)

    Drewnowski, Adam; Rehm, Colin D; Martin, Agnes; Verger, Eric O; Voinnesson, Marc; Imbert, Philippe

    2015-01-01

    A carbon footprint is the sum of greenhouse gas emissions (GHGEs) associated with food production, processing, transporting, and retailing. We examined the relation between the energy and nutrient content of foods and associated GHGEs as expressed as g CO2 equivalents. GHGE values, which were calculated and provided by a French supermarket chain, were merged with the Composition Nutritionnelle des Aliments (French food-composition table) nutrient-composition data for 483 foods and beverages from the French Agency for Food, Environmental and Occupational Health and Safety. Foods were aggregated into 34 food categories and 5 major food groups as follows: meat and meat products, milk and dairy products, frozen and processed fruit and vegetables, grains, and sweets. Energy density was expressed as kcal/100 g. Nutrient density was determined by using 2 alternative nutrient-density scores, each based on the sum of the percentage of daily values for 6 or 15 nutrients, respectively. The energy and nutrient densities of foods were linked to log-transformed GHGE values expressed per 100 g or 100 kcal. Grains and sweets had lowest GHGEs (per 100 g and 100 kcal) but had high energy density and a low nutrient content. The more-nutrient-dense animal products, including meat and dairy, had higher GHGE values per 100 g but much lower values per 100 kcal. In general, a higher nutrient density of foods was associated with higher GHGEs per 100 kcal, although the slopes of fitted lines varied for meat and dairy compared with fats and sweets. Considerations of the environmental impact of foods need to be linked to concerns about nutrient density and health. The point at which the higher carbon footprint of some nutrient-dense foods is offset by their higher nutritional value is a priority area for additional research. © 2015 American Society for Nutrition.

  1. A comparison of bone mineral density in osteoporotic fracture of the proximal femur using dual energy X-ray absorptiometry

    International Nuclear Information System (INIS)

    Lee, Jong Seok; Yoo, Beong Gyu; Kim, Keung Sik

    2000-01-01

    There were some controversies about direct cause of hip fracture. We attempted to look at 40 osteoporotic proximal femur fractures in women over 50 years between March in 1999 and February in 2000. The bone density of the fracture group and the healthy 85 control group was measured by Dual Energy X-ray absorptiometry (DEXA). The result was compared using age matched paired T test. The results were as follows: The femoral neck fractures were 14 cases and the trochanteric fractures were 26 cases. Mean age at a fracture was 67.1 years in neck fracture group and 76.5 years in trochanteric fracture. In the control group, the bone density of both side of the proximal femur was measured and it showed statistically no difference between both sides in same person. The bone density of neck, Ward's triangle, trochanter (P<0.05) and lumbar spine (P<0.001) was significantly reduced in the proximal femoral fracture group comparing with the control group. The bone density of neck, Ward's triangle, trochanter (P<0.05) was significantly reduced in the proximal femoral neck fracture group comparing with the control group, but there was no statistical difference in lumbar spine comparing with the control group. The bone density of neck, Ward's triangle, trochanter and lumbar spine (P<0.001) was significantly reduced in the proximal femoral neck fracture group comparing with the control group. We concluded that the bone mineral densities (BMD) of proximal femur and lumbar spine had decreased in hip fractures but that the bone mineral density and T-score % of the proximal femur were statistically lower than that of the lumbar spine. We suggest that measuring the bone mineral density of the proximal femur may reflect the weakness of the proximal femur more precisely than measuring the bone mineral density of the lumbar spine

  2. A comparison of bone mineral density in osteoporotic fracture of the proximal femur using dual energy X-ray absorptiometry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Seok; Yoo, Beong Gyu [Wonkwang Health Science College, Iksan (Korea, Republic of); Kim, Keung Sik [Yonsei University Yong Dong Severance Hospital, Seoul (Korea, Republic of)

    2000-04-15

    There were some controversies about direct cause of hip fracture. We attempted to look at 40 osteoporotic proximal femur fractures in women over 50 years between March in 1999 and February in 2000. The bone density of the fracture group and the healthy 85 control group was measured by Dual Energy X-ray absorptiometry (DEXA). The result was compared using age matched paired T test. The results were as follows: The femoral neck fractures were 14 cases and the trochanteric fractures were 26 cases. Mean age at a fracture was 67.1 years in neck fracture group and 76.5 years in trochanteric fracture. In the control group, the bone density of both side of the proximal femur was measured and it showed statistically no difference between both sides in same person. The bone density of neck, Ward's triangle, trochanter (P<0.05) and lumbar spine (P<0.001) was significantly reduced in the proximal femoral fracture group comparing with the control group. The bone density of neck, Ward's triangle, trochanter (P<0.05) was significantly reduced in the proximal femoral neck fracture group comparing with the control group, but there was no statistical difference in lumbar spine comparing with the control group. The bone density of neck, Ward's triangle, trochanter and lumbar spine (P<0.001) was significantly reduced in the proximal femoral neck fracture group comparing with the control group. We concluded that the bone mineral densities (BMD) of proximal femur and lumbar spine had decreased in hip fractures but that the bone mineral density and T-score % of the proximal femur were statistically lower than that of the lumbar spine. We suggest that measuring the bone mineral density of the proximal femur may reflect the weakness of the proximal femur more precisely than measuring the bone mineral density of the lumbar spine.

  3. Nonlinear dielectric thin films for high-power electric storage with energy density comparable with electrochemical supercapacitors.

    Science.gov (United States)

    Yao, Kui; Chen, Shuting; Rahimabady, Mojtaba; Mirshekarloo, Meysam Sharifzadeh; Yu, Shuhui; Tay, Francis Eng Hock; Sritharan, Thirumany; Lu, Li

    2011-09-01

    Although batteries possess high energy storage density, their output power is limited by the slow movement of charge carriers, and thus capacitors are often required to deliver high power output. Dielectric capacitors have high power density with fast discharge rate, but their energy density is typically much lower than electrochemical supercapacitors. Increasing the energy density of dielectric materials is highly desired to extend their applications in many emerging power system applications. In this paper, we review the mechanisms and major characteristics of electric energy storage with electrochemical supercapacitors and dielectric capacitors. Three types of in-house-produced ferroic nonlinear dielectric thin film materials with high energy density are described, including (Pb(0.97)La(0.02))(Zr(0.90)Sn(0.05)Ti(0.05))O(3) (PLZST) antiferroelectric ceramic thin films, Pb(Zn(1/3)Nb(2/3))O(3-)Pb(Mg(1/3)Nb(2/3))O(3-)PbTiO(3) (PZN-PMN-PT) relaxor ferroelectric ceramic thin films, and poly(vinylidene fluoride) (PVDF)-based polymer blend thin films. The results showed that these thin film materials are promising for electric storage with outstandingly high power density and fairly high energy density, comparable with electrochemical supercapacitors.

  4. Reduced density matrix embedding. General formalism and inter-domain correlation functional.

    Science.gov (United States)

    Pernal, Katarzyna

    2016-08-03

    An embedding method for a one-electron reduced density matrix (1-RDM) is proposed. It is based on partitioning of 1-RDM into domains and describing each domain in the effective potential of the other ones. To assure N-representability of the total 1-RDM N-representability and strong-orthogonality conditions are imposed on the domains. The total energy is given as a sum of single-domain energies and domain-domain electron interaction contributions. Higher than two-body inter-domain interaction terms are neglected. The two-body correlation terms are approximated by deriving inter-domain correlation from couplings of density fluctuations of two domains at a time. Unlike in most density embedding methods kinetic energy is treated exactly and it is not required that densities pertaining to the domains are only weakly overlapping. We propose to treat each domain by a corrected perfect-pairing functional. On a few examples it is shown that the embedding reduced density matrix functional method (ERDMF) yields excellent results for molecules that are well described by a single Lewis structure even if strong static intra-domain or dynamic inter-domain correlation effects must be accounted for.

  5. Local thermodynamic equilibrium in rapidly heated high energy density plasmas

    International Nuclear Information System (INIS)

    Aslanyan, V.; Tallents, G. J.

    2014-01-01

    Emission spectra and the dynamics of high energy density plasmas created by optical and Free Electron Lasers (FELs) depend on the populations of atomic levels. Calculations of plasma emission and ionization may be simplified by assuming Local Thermodynamic Equilibrium (LTE), where populations are given by the Saha-Boltzmann equation. LTE can be achieved at high densities when collisional processes are much more significant than radiative processes, but may not be valid if plasma conditions change rapidly. A collisional-radiative model has been used to calculate the times taken by carbon and iron plasmas to reach LTE at varying densities and heating rates. The effect of different energy deposition methods, as well as Ionization Potential Depression are explored. This work shows regimes in rapidly changing plasmas, such as those created by optical lasers and FELs, where the use of LTE is justified, because timescales for plasma changes are significantly longer than the times needed to achieve an LTE ionization balance

  6. Correlation Among the Variant Group, Effective Grain Size, and Elastic Strain Energy During the Phase Transformation in 9Ni Steels

    Science.gov (United States)

    Terasaki, Hidenori; Moriguchi, Koji; Tomio, Yusaku; Yamagishi, Hideki; Morito, Shigekazu

    2017-12-01

    The effect of carbon content on the density of variant-pair boundaries was investigated in 9Ni steel using an electron backscatter diffraction patterns method. The changes in the density of variant-pair boundaries were correlated with the nondestructive measured values of shear modulus of the austenite phase at the phase transformation point. Furthermore, the effective grain size was correlated with the shear modulus and the density of variant-pair boundaries. These relations are discussed from the viewpoint of self-accommodation of elastic strain energy and the nucleation event in the bainite and martensitic transformations.

  7. Understanding the major uncertainties in the nuclear symmetry energy at suprasaturation densities

    International Nuclear Information System (INIS)

    Xu Chang; Li Baoan

    2010-01-01

    Within the interacting Fermi gas model for isospin asymmetric nuclear matter, effects of the in-medium three-body interaction and the two-body short-range tensor force owing to the ρ meson exchange, as well as the short-range nucleon correlation on the high-density behavior of the nuclear symmetry energy, are demonstrated respectively in a transparent way. Possible physics origins of the extremely uncertain nuclear symmetry energy at suprasaturation densities are discussed.

  8. Drell-Yan lepton pair photoproduction

    International Nuclear Information System (INIS)

    Badalyan, R.G.; Grabskij, V.O.; Matinyan, S.G.

    1989-01-01

    The study of photon structure functions by spectra of massive lepton pairs (M l + l - ≥ 2 GeV) in photon fragmentation region in γp-interactions at high energies is suggested. In calculations of Drell-Yan lepton pair inclusive spectra in γp-interactions for photon structure functions there are used results obtained within QCD, data on γγ-interactions in e + e - → e + e - X on colliders as well as results from the analysis of vector meson non-diffractive photoproduction at high energies. It is shown that there exists a sufficienly wide kinematic region over variables X l + l - and M l + l - , wherein photon structure functions can be studied by spectra of Grell-Yan lepton pairs in the processes of their photoproduction. 31 refs.; 6 figs.; 1 tab

  9. Role of the pair potential for the saturation of generalized Pauli constraints

    Science.gov (United States)

    Legeza, Örs; Schilling, Christian

    2018-05-01

    The dependence of the (quasi-)saturation of the generalized Pauli constraints on the pair potential is studied for ground states of few-fermion systems. For this, we consider spinless fermions in one dimension which are harmonically confined and interact by pair potentials of the form | xi-xj|s with -1 ≤s ≤5 . We use the density matrix renormalization group approach and large orbital basis to achieve the convergence on more than ten digits of both the variational energy and the natural occupation numbers. Our results confirm that the conflict between energy minimization and fermionic exchange symmetry results in a universal and nontrivial quasisaturation of the generalized Pauli constraints (quasipinning), implying tremendous structural simplifications of the fermionic ground state for all s . Those numerically exact results are complemented by an analytical study based on a self-consistent perturbation theory which we develop for this purpose. The respective results for the weak-coupling regime eventually elucidate the singular behavior found for the specific values s =2 ,4 ,..., resulting in an extremely strong quasipinning.

  10. Recoil effects in multiphoton electron-positron pair creation

    International Nuclear Information System (INIS)

    Krajewska, K.; Kaminski, J. Z.

    2010-01-01

    Triply differential probability rates for electron-positron pair creation in laser-nucleus collisions, calculated within the S-matrix approach, are investigated as functions of the nuclear recoil. Pronounced enhancements of differential probability rates of multiphoton pair production are found for a nonzero momentum transfer from the colliding nucleus. The corresponding rates show a very dramatic dependence on the polarization of the laser field impinging on the nucleus; only for a linearly polarized light are the multiphoton rates for electron-positron pair production considerably large. We focus therefore on this case. Our numerical results for different geometries of the reaction particles demonstrate that, for the linearly polarized laser field of an infinite extent (which is a good approximation for femtosecond laser pulses), the pair creation is far more efficient if the nucleus is detected in the direction of the laser-field propagation. The corresponding angular distributions of the created particles show that the high-energy pairs are predominantly produced in the plane spanned by the polarization vector and the laser-field propagation direction, while the low-energy pairs are rather spread around the latter of the two directions. The enhancement of differential probability rates at each energy sector, defined by the four-momentum conservation relation, is observed with varying the energy of the produced particles. The total probability rates of pair production are also evaluated and compared with the corresponding results for the case when one disregards the recoil effect. A tremendous enhancement of the total probability rates of the electron-positron pair creation is observed if one takes into account the nuclear recoil.

  11. e+e- Pair production from 10 GeV to 10 ZeV

    International Nuclear Information System (INIS)

    Klein, Spencer R.

    2006-01-01

    At very high energies, pair production (γ->e + e - ) exhibits many interesting features. The momentum transfer from the target is very small, so the reaction probes the macroscopic properties of the target, rather than individual nuclei. Interference between interactions with different atoms reduces the pair production cross section considerably below the Bethe-Heitler values. At very high energies, photonuclear interactions may outnumber pair production. In contrast, in crystals, the interaction amplitudes may add coherently, greatly increasing the cross sections. Pair production in matter-free magnetic fields is also possible. The highest energy pair production occurs at high-energy particle colliders. This article will compare pair production in these very different regimes

  12. High-Energy-Density Metal-Oxygen Batteries: Lithium-Oxygen Batteries vs Sodium-Oxygen Batteries.

    Science.gov (United States)

    Song, Kyeongse; Agyeman, Daniel Adjei; Park, Mihui; Yang, Junghoon; Kang, Yong-Mook

    2017-12-01

    The development of next-generation energy-storage devices with high power, high energy density, and safety is critical for the success of large-scale energy-storage systems (ESSs), such as electric vehicles. Rechargeable sodium-oxygen (Na-O 2 ) batteries offer a new and promising opportunity for low-cost, high-energy-density, and relatively efficient electrochemical systems. Although the specific energy density of the Na-O 2 battery is lower than that of the lithium-oxygen (Li-O 2 ) battery, the abundance and low cost of sodium resources offer major advantages for its practical application in the near future. However, little has so far been reported regarding the cell chemistry, to explain the rate-limiting parameters and the corresponding low round-trip efficiency and cycle degradation. Consequently, an elucidation of the reaction mechanism is needed for both lithium-oxygen and sodium-oxygen cells. An in-depth understanding of the differences and similarities between Li-O 2 and Na-O 2 battery systems, in terms of thermodynamics and a structural viewpoint, will be meaningful to promote the development of advanced metal-oxygen batteries. State-of-the-art battery design principles for high-energy-density lithium-oxygen and sodium-oxygen batteries are thus reviewed in depth here. Major drawbacks, reaction mechanisms, and recent strategies to improve performance are also summarized. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Flexible Aqueous Li-Ion Battery with High Energy and Power Densities.

    Science.gov (United States)

    Yang, Chongyin; Ji, Xiao; Fan, Xiulin; Gao, Tao; Suo, Liumin; Wang, Fei; Sun, Wei; Chen, Ji; Chen, Long; Han, Fudong; Miao, Ling; Xu, Kang; Gerasopoulos, Konstantinos; Wang, Chunsheng

    2017-11-01

    A flexible and wearable aqueous symmetrical lithium-ion battery is developed using a single LiVPO 4 F material as both cathode and anode in a "water-in-salt" gel polymer electrolyte. The symmetric lithium-ion chemistry exhibits high energy and power density and long cycle life, due to the formation of a robust solid electrolyte interphase consisting of Li 2 CO 3 -LiF, which enables fast Li-ion transport. Energy densities of 141 Wh kg -1 , power densities of 20 600 W kg -1 , and output voltage of 2.4 V can be delivered during >4000 cycles, which is far superior to reported aqueous energy storage devices at the same power level. Moreover, the full cell shows unprecedented tolerance to mechanical stress such as bending and cutting, where it not only does not catastrophically fail, as most nonaqueous cells would, but also maintains cell performance and continues to operate in ambient environment, a unique feature apparently derived from the high stability of the "water-in-salt" gel polymer electrolyte. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Blinking fluorescence of single donor-acceptor pairs: important role of "dark'' states in resonance energy transfer via singlet levels.

    Science.gov (United States)

    Osad'ko, I S; Shchukina, A L

    2012-06-01

    The influence of triplet levels on Förster resonance energy transfer via singlet levels in donor-acceptor (D-A) pairs is studied. Four types of D-A pair are considered: (i) two-level donor and two-level acceptor, (ii) three-level donor and two-level acceptor, (iii) two-level donor and three-level acceptor, and (iv) three-level donor and three-level acceptor. If singlet-triplet transitions in a three-level acceptor molecule are ineffective, the energy transfer efficiency E=I_{A}/(I_{A}+I_{D}), where I_{D} and I_{A} are the average intensities of donor and acceptor fluorescence, can be described by the simple theoretical equation E(F)=FT_{D}/(1+FT_{D}). Here F is the rate of energy transfer, and T_{D} is the donor fluorescence lifetime. In accordance with the last equation, 100% of the donor electronic energy can be transferred to an acceptor molecule at FT_{D}≫1. However, if singlet-triplet transitions in a three-level acceptor molecule are effective, the energy transfer efficiency is described by another theoretical equation, E(F)=F[over ¯](F)T_{D}/[1+F[over ¯](F)T_{D}]. Here F[over ¯](F) is a function of F depending on singlet-triplet transitions in both donor and acceptor molecules. Expressions for the functions F[over ¯](F) are derived. In this case the energy transfer efficiency will be far from 100% even at FT_{D}≫1. The character of the intensity fluctuations of donor and acceptor fluorescence indicates which of the two equations for E(F) should be used to find the value of the rate F. Therefore, random time instants of photon emission in both donor and acceptor fluorescence are calculated by the Monte Carlo method for all four types of D-A pair. Theoretical expressions for start-stop correlators (waiting time distributions) in donor and acceptor fluorescence are derived. The probabilities w_{N}^{D}(t) and w_{N}^{A}(t) of finding N photons of donor and acceptor fluorescence in the time interval t are calculated for various values of the energy

  15. High Energy-Density Lithium-Sulfur Batteries with Extended Cycle Life, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Conventional lithium-ion batteries demonstrate great potential for energy storage applications but they face some major challenges such as low energy density and...

  16. Visualization and analysis of pulsed ion beam energy density profile with infrared imaging

    Science.gov (United States)

    Isakova, Y. I.; Pushkarev, A. I.

    2018-03-01

    Infrared imaging technique was used as a surface temperature-mapping tool to characterize the energy density distribution of intense pulsed ion beams on a thin metal target. The technique enables the measuring of the total ion beam energy and the energy density distribution along the cross section and allows one to optimize the operation of an ion diode and control target irradiation mode. The diagnostics was tested on the TEMP-4M accelerator at TPU, Tomsk, Russia and on the TEMP-6 accelerator at DUT, Dalian, China. The diagnostics was applied in studies of the dynamics of the target cooling in vacuum after irradiation and in the experiments with target ablation. Errors caused by the target ablation and target cooling during measurements have been analyzed. For Fluke Ti10 and Fluke Ti400 infrared cameras, the technique can achieve surface energy density sensitivity of 0.05 J/cm2 and spatial resolution of 1-2 mm. The thermal imaging diagnostics does not require expensive consumed materials. The measurement time does not exceed 0.1 s; therefore, this diagnostics can be used for the prompt evaluation of the energy density distribution of a pulsed ion beam and during automation of the irradiation process.

  17. Odd-frequency pairing in superconducting heterostructures .

    Science.gov (United States)

    Golubov, A. A.; Tanaka, Y.; Yokoyama, T.; Asano, Y.

    2007-03-01

    We present a general theory of the proximity effect in junctions between unconventional superconductors and diffusive normal metals (DN) or ferromagnets (DF). We consider all possible symmetry classes in a superconductor allowed by the Pauli principle: even-frequency spin-singlet even-parity state, even-frequency spin-triplet odd-parity state, odd-frequency spin-triplet even-parity state and odd-frequency spin-singlet odd-parity state. For each of the above states, symmetry and spectral properties of the induced pair amplitude in the DN (DF) are determined. The cases of junctions with spin-singlet s- and d-wave superconductors and spin-triplet p-wave superconductors are adressed in detail. We discuss the interplay between the proximity effect and midgap Andreev bound states arising at interfaces in unconventional (d- or p-wave) junctions. The most striking property is the odd-frequency symmetry of the pairing amplitude induced in DN (DF) in contacts with p-wave superconductors. This leads to zero-energy singularity in the density of states and to anomalous screening of an external magnetic field. Peculiarities of Josephson effect in d- or p-wave junctions are discussed. Experiments are suggested to detect an order parameter symmetry using heterostructures with unconventional superconductors.

  18. Population density and efficiency in energy consumption: An empirical analysis of service establishments

    International Nuclear Information System (INIS)

    Morikawa, Masayuki

    2012-01-01

    This study, using novel establishment-level microdata from the Energy Consumption Statistics, empirically analyzes the effect of urban density on energy intensity in the service sector. According to the analysis, the efficiency of energy consumption in service establishments is higher for densely populated cities. Quantitatively, after controlling for differences among industries, energy efficiency increases by approximately 12% when the density in a municipality population doubles. This result suggests that, given a structural transformation toward the service economy, deregulation of excessive restrictions hindering urban agglomeration, and investment in infrastructure in city centers would contribute to environmentally friendly economic growth.

  19. Assessing the effect of electron density in photon dose calculations

    International Nuclear Information System (INIS)

    Seco, J.; Evans, P. M.

    2006-01-01

    to be a consequence of the differences in the hydrogen content between the various media studied and water. On the other hand, the electron-density scaling method was shown to predict primary photon fluence in media other than water to within 1%-2% for all the materials studied and for energies up to 5 MeV. For energies above 5 MeV, the accuracy of the electron-density scaling method was shown to depend on the photon energy, where for materials with a high content of calcium (such as bone, cortical bone) or for primary photon energies above 10 MeV, the pair-production process could no longer be neglected. The electron-density scaling method was extended to account for pair-production attenuation of the primary photons. Therefore the scaling of the dose distributions in media other than water became dependent on the photon energy. The extended electron-scaling method was shown to estimate the photon range to within 1% for all materials studied and for energies from 100 keV to 20 MeV, allowing it to be used to scale dose distributions to media other than water and generated by clinical radiotherapy photon beams with accelerator energies from 4 to 20 MV

  20. Inflation of the screening length induced by Bjerrum pairs

    NARCIS (Netherlands)

    Zwanikken, J.W.; van Roij, R.H.H.G.

    2009-01-01

    Within a modified Poisson–Boltzmann theory we study the effect of Bjerrum pairs on the typical length scale 1/¯κ over which electric fields are screened in electrolyte solutions, taking into account a simple association–dissociation equilibrium between free ions and Bjerrum pairs. At low densities

  1. Symmetry energy of the nucleus in the relativistic Thomas-Fermi approach with density-dependent parameters

    Science.gov (United States)

    Haddad, S.

    2017-11-01

    The symmetry energy of a nucleus is determined in a local density approximation and integrating over the entire density distribution of the nucleus, calculated utilizing the relativistic density-dependent Thomas-Fermi approach. The symmetry energy is found to decrease with increasing neutron excess in the nucleus. The isovector coupling channel reduces the symmetry energy, and this effect increases with increased neutron excess. The isovector coupling channel increases the symmetry energy integral in ^{40}Ca and reduces it in ^{48}Ca, and the interplay between the isovector and the isoscalar channels of the nuclear force explains this isotope effect.

  2. Density-scaling exponents and virial potential-energy correlation ...

    Indian Academy of Sciences (India)

    This paper investigates the relation between the density-scaling exponent γ and the virial potential energy correlation coefficient R at several thermodynamic state points in three dimensions for the generalized (2n, n) Lennard-Jones (LJ) system for n = 4, 9, 12, 18, as well as for the standard n = 6 LJ system in two,three, and ...

  3. Learning about the energy density of liquid and semi-solid foods.

    Science.gov (United States)

    Hogenkamp, P S; Stafleu, A; Mars, M; de Graaf, C

    2012-09-01

    People learn about a food's satiating capacity by exposure and consequently adjust their energy intake. To investigate the effect of energy density and texture on subsequent energy intake adjustments during repeated consumption. In a randomized crossover design, participants (n=27, age: 21±2.4 years, body mass index: 22.2±1.6 kg m(-2)) repeatedly consumed highly novel foods that were either low-energy-dense (LE: 30 kcal per 100 g) or high-energy-dense (HE: 130 kcal per 100 g), and either liquid or semi-solid, resulting in four product conditions. In each condition, a fixed portion of test food was consumed nine times as an obligatory part of breakfast, lunch and dinner on 3 consecutive days. All meals continued with an ad libitum buffet; food items for evening consumption were provided and the intake (kcal per day) was measured. Buffet intake depended on energy density and day of consumption of the test foods (day*energy interaction: P=0.02); daily buffet intake increased from day 1 (1745±577 kcal) to day 3 (1979±567 kcal) in the LE conditions; intake did not change in the HE conditions (day 1: 1523±429 kcal, day 3: 1589±424 kcal). Food texture did not affect the intake (P=0.56). Intake did depend on energy density of the test foods; participants increased their buffet intake over days in response to learning about the satiating capacity of the LE foods, but did not change buffet intake over days when repeatedly consuming a HE food as part of their meal. The adjustments in intake were made irrespective of the food texture.

  4. Energy-density enhancement of carbon-nanotube-based supercapacitors with redox couple in organic electrolyte.

    Science.gov (United States)

    Park, Jinwoo; Kim, Byungwoo; Yoo, Young-Eun; Chung, Haegeun; Kim, Woong

    2014-11-26

    We demonstrate for the first time that the incorporation of a redox-active molecule in an organic electrolyte can increase the cell voltage of a supercapacitor. The redox molecule also contributes to increasing the cell capacitance by a faradaic redox reaction, and therefore the energy density of the supercapacitor can be significantly increased. More specifically, the addition of redox-active decamethylferrocene in an organic electrolyte results in an approximately 27-fold increase in the energy density of carbon-nanotube-based supercapacitors. The resulting high energy density (36.8 Wh/kg) stems from the increased cell voltage (1.1 V→2.1 V) and cell capacitance (8.3 F/g→61.3 F/g) resulting from decamethylferrocene addition. We found that the voltage increase is associated with the potential of the redox species relative to the electrochemical stability window of the supporting electrolyte. These results will be useful in identifying new electrolytes for high-energy-density supercapacitors.

  5. Cowichan Valley energy mapping and modelling. Report 2 - Energy consumption and density mapping. Final report. [Vancouver Island, Canada

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-06-15

    The driving force behind the Integrated Energy Mapping and Analysis project was the identification and analysis of a suite of pathways that the Cowichan Valley Regional District (CVRD) can utilise to increase its energy resilience, as well as reduce energy consumption and GHG emissions, with a primary focus on the residential sector. Mapping and analysis undertaken will support provincial energy and GHG reduction targets, and the suite of pathways outlined will address a CVRD internal target that calls for 75% of the region's energy within the residential sector to come from locally sourced renewables by 2050. The target has been developed as a mechanism to meet resilience and climate action target. The maps and findings produced are to be integrated as part of a regional policy framework currently under development. The second task in the overall project was the mapping of regional energy consumption density. Combined with the findings from task one, this enables comparison of energy consumption density per area unit with the renewable energy resource availability. In addition, it provides an energy baseline against which future energy planning activities can be evaluated. The mapping of the energy consumption density was divided into categories to correspond with local British Columbia Assessment Authority (BCAA) reporting. The residential sub-categories were comprised of single family detached dwellings, single family attached dwellings, apartments, and moveable dwellings. For commercial and industrial end-users the 14 sub-categories are also in line with BCAA as well as the on-going provincial TaNDM project of which the CVRD is a partner. The results of task two are documented in this report. (LN)

  6. Extending the magnetoelectric efficiency of an MFC/brass/NdFeB energy harvester by coupling a pair of movable magnets

    Science.gov (United States)

    Leung, Chung Ming; Wang, Ya

    2017-10-01

    In this letter, an MFC/brass/NdFeB tip magnet three-phase cantilever beam was coupled with a pair of movable magnets to harness energy from alternating magnetic fields. By coupling with a pair of moveable magnets, both bandwidth and magnetoelectric (ME) voltage coefficient (α\\text{V}) were largely increased by 25% and 87.5%, respectively, in comparison with the same harvester coupled with stationary magnets. Such improvements were attributed to magnetic energy introduced by the moving magnets. Experiments also revealed the boundary positions of external magnets (movable and stationary) where the repulsive magnetic forces jumped to the attractive ones, and the stiffness hardening switched to the softening process. These results provided a wide-band nonlinear approach to efficiently harvest/detect the low-frequency alternating magnetic field energies.

  7. Thermal Condensate Structure and Cosmological Energy Density of the Universe

    Directory of Open Access Journals (Sweden)

    Antonio Capolupo

    2016-01-01

    Full Text Available The aim of this paper is to study thermal vacuum condensate for scalar and fermion fields. We analyze the thermal states at the temperature of the cosmic microwave background (CMB and we show that the vacuum expectation value of the energy momentum tensor density of photon fields reproduces the energy density and pressure of the CMB. We perform the computations in the formal framework of the Thermo Field Dynamics. We also consider the case of neutrinos and thermal states at the temperature of the neutrino cosmic background. Consistency with the estimated lower bound of the sum of the active neutrino masses is verified. In the boson sector, nontrivial contribution to the energy of the universe is given by particles of masses of the order of 10−4 eV compatible with the ones of the axion-like particles. The fractal self-similar structure of the thermal radiation is also discussed and related to the coherent structure of the thermal vacuum.

  8. Energy-momentum density of graphite by electron-momentum spectroscopy

    International Nuclear Information System (INIS)

    Vos, M.; Fang, Z.; Canney, S.; Kheifets, A.; McCarthy, I.E.; Weigold, E.

    1996-11-01

    The energy-resolved electron momentum density of graphite has been measured along a series of well-defined directions using electron momentum spectroscopy (EMS). This is the first measurement of this kind performed on a single-crystal target with a thoroughly controlled orientation which clearly demonstrates the different nature of the σ and π bands in graphite. Good agreement between the calculated density and the measured one is found, further establishing that fact that EMS yields more direct and complete information on the valence electronic structure that any other method. 12 refs., 2 figs

  9. Silver Niobate Lead-Free Antiferroelectric Ceramics: Enhancing Energy Storage Density by B-Site Doping.

    Science.gov (United States)

    Zhao, Lei; Gao, Jing; Liu, Qing; Zhang, Shujun; Li, Jing-Feng

    2018-01-10

    Lead-free dielectric ceramics with high recoverable energy density are highly desired to sustainably meet the future energy demand. AgNbO 3 -based lead-free antiferroelectric ceramics with double ferroelectric hysteresis loops have been proved to be potential candidates for energy storage applications. Enhanced energy storage performance with recoverable energy density of 3.3 J/cm 3 and high thermal stability with minimal energy density variation (<10%) over a temperature range of 20-120 °C have been achieved in W-modified AgNbO 3 ceramics. It is revealed that the W 6+ cations substitute the B-site Nb 5+ and reduce the polarizability of B-site cations, leading to the enhanced antiferroelectricity, which is confirmed by the polarization hysteresis and dielectric tunability. It is believed that the polarizability of B-site cations plays a dominant role in stabilizing the antiferroelectricity in AgNbO 3 system, in addition to the tolerance factor, which opens up a new design approach to achieve stable antiferroelectric materials.

  10. Pulsar Pair Cascades in Magnetic Fields with Offset Polar Caps

    Science.gov (United States)

    Harding, Alice K.; Muslimov, Alex G.

    2012-01-01

    Neutron star magnetic fields may have polar caps (PC) that are offset from the dipole axis, through field-line sweepback near the light cylinder or non-symmetric currents within the star. The effects of such offsets on electron-positron pair cascades are investigated, using simple models of dipole magnetic fields with small distortions that shift the PCs by different amounts or directions. Using a Monte Carlo pair cascade simulation, we explore the changes in the pair spectrum, multiplicity and energy flux across the PC, as well as the trends in pair flux and pair energy flux with spin-down luminosity, L(sub sd). We also give an estimate of the distribution of heating flux from returning positrons on the PC for different offsets. We find that even modest offsets can produce significant increases in pair multiplicity, especially for pulsars that are near or beyond the pair death lines for centered PCs, primarily because of higher accelerating fields. Pair spectra cover several decades in energy, with the spectral range of millisecond pulsars (MSPs) two orders of magnitude higher than for normal pulsars, and PC offsets allow significant extension of all spectra to lower pair energies. We find that the total PC pair luminosity L(sub pair) is proportional to L(sub sd), with L(sub pair) approximates 10(exp -3) L(sub sd) for normal pulsars and L(sub pair) approximates 10(exp -2) L(sub sd) for MSPs. Remarkably, the total PC heating luminosity for even large offsets increases by less than a factor of two, even though the PC area increases by much larger factors, because most of the heating occurs near the magnetic axis.

  11. Ultrafast deactivation processes in the 2-aminopyridine dimer and the adenine-thymine base pair: Similarities and differences

    International Nuclear Information System (INIS)

    Ai Yuejie; Zhang Feng; Cui Ganglong; Fang Weihai; Luo Yi

    2010-01-01

    2-aminopyridine dimer has frequently been used as a model system for studying photochemistry of DNA base pairs. We examine here the relevance of 2-aminopyridine dimer for a Watson-Crick adenine-thymine base pair by studying UV-light induced photodynamics along two main hydrogen bridges after the excitation to the localized 1 ππ* excited-state. The respective two-dimensional potential-energy surfaces have been determined by time-dependent density functional theory with Coulomb-attenuated hybrid exchange-correlation functional (CAM-B3LYP). Different mechanistic aspects of the deactivation pathway have been analyzed and compared in detail for both systems, while the related reaction rates have also be obtained from Monte Carlo kinetic simulations. The limitations of the 2-aminopyridine dimer as a model system for the adenine-thymine base pair are discussed.

  12. Edge-enriched, porous carbon-based, high energy density supercapacitors for hybrid electric vehicles.

    Science.gov (United States)

    Kim, Yong Jung; Yang, Cheol-Min; Park, Ki Chul; Kaneko, Katsumi; Kim, Yoong Ahm; Noguchi, Minoru; Fujino, Takeshi; Oyama, Shigeki; Endo, Morinobu

    2012-03-12

    Supercapacitors can store and deliver energy by a simple charge separation, and thus they could be an attractive option to meet transient high energy density in operating fuel cells and in electric and hybrid electric vehicles. To achieve such requirements, intensive studies have been carried out to improve the volumetric capacitance in supercapacitors using various types and forms of carbons including carbon nanotubes and graphenes. However, conventional porous carbons are not suitable for use as electrode material in supercapacitors for such high energy density applications. Here, we show that edge-enriched porous carbons are the best electrode material for high energy density supercapacitors to be used in vehicles as an auxiliary powertrain. Molten potassium hydroxide penetrates well-aligned graphene layers vertically and consequently generates both suitable pores that are easily accessible to the electrolyte and a large fraction of electrochemically active edge sites. We expect that our findings will motivate further research related to energy storage devices and also environmentally friendly electric vehicles. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Quantum Chromodynamics and Nuclear Physics at Extreme Energy Density

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, B.; Bass, S.A.; Chandrasekharan, S.; Mehen, T.; Springer, R.P.

    2005-11-07

    The report describes research in theoretical quantum chromodynamics, including effective field theories of hadronic interactions, properties of strongly interacting matter at extreme energy density, phenomenology of relativistic heavy ion collisions, and algorithms and numerical simulations of lattice gauge theory and other many-body systems.

  14. Quantum Chromodynamics and Nuclear Physics at Extreme Energy Density

    International Nuclear Information System (INIS)

    Mueller, B.; Bass, S.A.; Chandrasekharan, S.; Mehen, T.; Springer, R.P.

    2005-01-01

    The report describes research in theoretical quantum chromodynamics, including effective field theories of hadronic interactions, properties of strongly interacting matter at extreme energy density, phenomenology of relativistic heavy ion collisions, and algorithms and numerical simulations of lattice gauge theory and other many-body systems.

  15. Microelectromechanical high-density energy storage/rapid release system

    Science.gov (United States)

    Rodgers, M. Steven; Allen, James J.; Meeks, Kent D.; Jensen, Brian D.; Miller, Samuel L.

    1999-08-01

    One highly desirable characteristic of electrostatically driven microelectromechanical systems (MEMS) is that they consume very little power. The corresponding drawback is that the force they produce may be inadequate for many applications. It has previously been demonstrated that gear reduction units or microtransmissions can substantially increase the torque generated by microengines. Operating speed, however, is also reduced by the transmission gear ratio. Some applications require both high speed and high force. If this output is only required for a limited period of time, then energy could be stored in a mechanical system and rapidly released upon demand. We have designed, fabricated, and demonstrated a high-density energy storage/rapid release system that accomplishes this task. Built using a 5-level surface micromachining technology, the assembly closely resembles a medieval crossbow. Energy releases on the order of tens of nanojoules have already been demonstrated, and significantly higher energy systems are under development.

  16. Mechanical confinement for improved energy storage density in BNT-BT-KNN lead-free ceramic capacitors

    Directory of Open Access Journals (Sweden)

    Aditya Chauhan

    2014-08-01

    Full Text Available With the advent of modern power electronics, embedded circuits and non-conventional energy harvesting, the need for high performance capacitors is bound to become indispensible. The current state-of-art employs ferroelectric ceramics and linear dielectrics for solid state capacitance. However, lead-free ferroelectric ceramics propose to offer significant improvement in the field of electrical energy storage owing to their high discharge efficiency and energy storage density. In this regards, the authors have investigated the effects of compressive stress as a means of improving the energy storage density of lead-free ferroelectric ceramics. The energy storage density of 0.91(Bi0.5Na0.5TiO3-0.07BaTiO3-0.02(K0.5Na0.5NbO3 ferroelectric bulk ceramic was analyzed as a function of varying levels of compressive stress and operational temperature .It was observed that a peak energy density of 387 mJ.cm-3 was obtained at 100 MPa applied stress (25oC. While a maximum energy density of 568 mJ.cm-3 was obtained for the same stress at 80oC. These values are indicative of a significant, 25% and 84%, improvement in the value of stored energy compared to an unloaded material. Additionally, material's discharge efficiency has also been discussed as a function of operational parameters. The observed phenomenon has been explained on the basis of field induced structural transition and competitive domain switching theory.

  17. Augmented potential, energy densities, and virial relations in the weak- and strong-interaction limits of DFT

    Science.gov (United States)

    Vuckovic, Stefan; Levy, Mel; Gori-Giorgi, Paola

    2017-12-01

    The augmented potential introduced by Levy and Zahariev [Phys. Rev. Lett. 113, 113002 (2014)] is shifted with respect to the standard exchange-correlation potential of the Kohn-Sham density functional theory by a density-dependent constant that makes the total energy become equal to the sum of the occupied orbital energies. In this work, we analyze several features of this approach, focusing on the limit of infinite coupling strength and studying the shift and the corresponding energy density at different correlation regimes. We present and discuss coordinate scaling properties of the augmented potential, study its connection to the response potential, and use the shift to analyze the classical jellium and uniform gas models. We also study other definitions of the energy densities in relation to the functional construction by local interpolations along the adiabatic connection. Our findings indicate that the energy density that is defined in terms of the electrostatic potential of the exchange-correlation hole is particularly well suited for this purpose.

  18. Biopolymer-nanocarbon composite electrodes for use as high-energy high-power density electrodes

    Science.gov (United States)

    Karakaya, Mehmet; Roberts, Mark; Arcilla-Velez, Margarita; Zhu, Jingyi; Podila, Ramakrishna; Rao, Apparao

    2014-03-01

    Supercapacitors (SCs) address our current energy storage and delivery needs by combining the high power, rapid switching, and exceptional cycle life of a capacitor with the high energy density of a battery. Although activated carbon is extensively used as a supercapacitor electrode due to its inexpensive nature, its low specific capacitance (100-120 F/g) fundamentally limits the energy density of SCs. We demonstrate that a nano-carbon based mechanically robust, electrically conducting, free-standing buckypaper electrode modified with an inexpensive biorenewable polymer, viz., lignin increases the electrode's specific capacitance (~ 600-700 F/g) while maintaining rapid discharge rates. In these systems, the carbon nanomaterials provide the high surface area, electrical conductivity and porosity, while the redox polymers provide a mechanism for charge storage through Faradaic charge transfer. The design of redox polymers and their incorporation into nanomaterial electrodes will be discussed with a focus on enabling high power and high energy density electrodes. Research supported by US NSF CMMI Grant 1246800.

  19. Bone mineral density in elite adolescent female figure skaters

    Directory of Open Access Journals (Sweden)

    Prelack Kathy

    2012-12-01

    Full Text Available Abstract Elite adolescent figure skaters must accommodate both the physical demands of competitive training and the accelerated rate of bone growth that is associated with adolescence, in this sport that emphasizes leanness. Although, these athletes apparently have sufficient osteogenic stimuli to mitigate the effects of possible low energy availability on bone health, the extent or magnitude of bone accrual also varies with training effects, which differ among skater disciplines. Purpose We studied differences in total and regional bone mineral density in 36 nationally ranked skaters among 3 skater disciplines: single, pairs, and dancers. Methods Bone mineral density (BMD of the total body and its regions was measured by dual energy x-ray absorptiometry (DXA. Values for total body, spine, pelvis and leg were entered into a statistical mixed regression model to identify the effect of skater discipline on bone mineralization while controlling for energy, vitamin D, and calcium intake. Results The skaters had a mean body mass index of 19.8 ± 2.1 and % fat mass of 19.2 ± 5.8. After controlling for dietary intakes of energy, calcium, and vitamin D, there was a significant relationship between skater discipline and BMD (p = 0.002, with single skaters having greater BMD in the total body, legs, and pelvis than ice dancers (p  Conclusions Single and pair skaters have greater BMD than ice dancers. The osteogenic effect of physical training is most apparent in single skaters, particularly in the bone loading sites of the leg and pelvis.

  20. Energy relaxation and separation of a hot electron-hole pair in organic aggregates from a time-dependent wavepacket diffusion method

    International Nuclear Information System (INIS)

    Han, Lu; Liang, WanZhen; Zhao, Yi; Zhong, Xinxin

    2014-01-01

    The time-dependent wavepacket diffusive method [X. Zhong and Y. Zhao, J. Chem. Phys. 138, 014111 (2013)] is extended to investigate the energy relaxation and separation of a hot electron-hole pair in organic aggregates with incorporation of Coulomb interaction and electron-phonon coupling. The pair initial condition generated by laser pulse is represented by a Gaussian wavepacket with a central momentum. The results reveal that the hot electron energy relaxation is very well described by two rate processes with the fast rate much larger than the slow one, consistent with experimental observations, and an efficient electron-hole separation is accomplished accompanying the fast energy relaxation. Furthermore, although the extra energy indeed helps the separation by overcoming the Coulomb interaction, the width of initial wavepacket is much sensitive to the separation efficiency and the narrower wavepacket generates the more separated charges. This behavior may be useful to understand the experimental controversy of the hot carrier effect on charge separation

  1. High-energy density nonaqueous all redox flow lithium battery enabled with a polymeric membrane.

    Science.gov (United States)

    Jia, Chuankun; Pan, Feng; Zhu, Yun Guang; Huang, Qizhao; Lu, Li; Wang, Qing

    2015-11-01

    Redox flow batteries (RFBs) are considered one of the most promising large-scale energy storage technologies. However, conventional RFBs suffer from low energy density due to the low solubility of the active materials in electrolyte. On the basis of the redox targeting reactions of battery materials, the redox flow lithium battery (RFLB) demonstrated in this report presents a disruptive approach to drastically enhancing the energy density of flow batteries. With LiFePO4 and TiO2 as the cathodic and anodic Li storage materials, respectively, the tank energy density of RFLB could reach ~500 watt-hours per liter (50% porosity), which is 10 times higher than that of a vanadium redox flow battery. The cell exhibits good electrochemical performance under a prolonged cycling test. Our prototype RFLB full cell paves the way toward the development of a new generation of flow batteries for large-scale energy storage.

  2. High–energy density nonaqueous all redox flow lithium battery enabled with a polymeric membrane

    Science.gov (United States)

    Jia, Chuankun; Pan, Feng; Zhu, Yun Guang; Huang, Qizhao; Lu, Li; Wang, Qing

    2015-01-01

    Redox flow batteries (RFBs) are considered one of the most promising large-scale energy storage technologies. However, conventional RFBs suffer from low energy density due to the low solubility of the active materials in electrolyte. On the basis of the redox targeting reactions of battery materials, the redox flow lithium battery (RFLB) demonstrated in this report presents a disruptive approach to drastically enhancing the energy density of flow batteries. With LiFePO4 and TiO2 as the cathodic and anodic Li storage materials, respectively, the tank energy density of RFLB could reach ~500 watt-hours per liter (50% porosity), which is 10 times higher than that of a vanadium redox flow battery. The cell exhibits good electrochemical performance under a prolonged cycling test. Our prototype RFLB full cell paves the way toward the development of a new generation of flow batteries for large-scale energy storage. PMID:26702440

  3. Top quark pair production in ATLAS

    CERN Document Server

    Moreno Llacer, M; The ATLAS collaboration

    2010-01-01

    Top-quark pairs are expected to be produced at the LHC, even at the lower beam energy and luminosity in the first years of running. Establishing the top-pair signal and measuring the production cross-section are important benchmarks for ATLAS, and will help understand the detector performance for events with high-pT leptons, high jet multiplicity, missing transverse energy. The prospects for early top physics measurements will be shown, with a particular emphasis on the progress achieved with data so far.

  4. High energy density Z-pinch plasmas using flow stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Shumlak, U., E-mail: shumlak@uw.edu; Golingo, R. P., E-mail: shumlak@uw.edu; Nelson, B. A., E-mail: shumlak@uw.edu; Bowers, C. A., E-mail: shumlak@uw.edu; Doty, S. A., E-mail: shumlak@uw.edu; Forbes, E. G., E-mail: shumlak@uw.edu; Hughes, M. C., E-mail: shumlak@uw.edu; Kim, B., E-mail: shumlak@uw.edu; Knecht, S. D., E-mail: shumlak@uw.edu; Lambert, K. K., E-mail: shumlak@uw.edu; Lowrie, W., E-mail: shumlak@uw.edu; Ross, M. P., E-mail: shumlak@uw.edu; Weed, J. R., E-mail: shumlak@uw.edu [Aerospace and Energetics Research Program, University of Washington, Seattle, Washington, 98195-2250 (United States)

    2014-12-15

    The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes – Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and

  5. CsI Calorimeter for a Compton-Pair Telescope

    Science.gov (United States)

    Grove, Eric J.

    We propose to build and test a hodoscopic CsI(Tl) scintillating-crystal calorimeter for a medium-energy γ-ray Compton and pair telescope. The design and technical approach for this calorimeter relies deeply on heritage from the Fermi LAT CsI Calorimeter, but it dramatically improves the low-energy performance of that design by reading out the scintillation light with silicon photomultipliers (SiPMs), making the technology developed for Fermi applicable in the Compton regime. While such a hodoscopic calorimeter is useful for an entire class of medium-energy γ-ray telescope designs, we propose to build it explicitly to support beam tests and balloon flight of the Proto-ComPair telescope, the development and construction of which was funded in a four-year APRA program beginning in 2015 ("ComPair: Steps to a Medium Energy γ-ray Mission" with PI J. McEnery of GSFC). That award did not include funding for its CsI calorimeter subsystem, and this proposal is intended to cover that gap. ComPair is a MIDEX-class instrument concept to perform a high-sensitivity survey of the γ-ray sky from 0.5 MeV to 500 MeV. ComPair is designed to provide a dramatic increase in sensitivity relative to previous instruments in this energy range (predominantly INTEGRAL/SPI and Compton COMPTEL), with the same transformative sensitivity increase - and corresponding scientific return- that the Fermi Large Area Telescope provided relative to Compton EGRET. To enable transformative science over a broad range of MeV energies and with a wide field of view, ComPair is a combined Compton telescope and pair telescope employing a silicon-strip tracker (for Compton scattering and pair conversion and tracking) and a solid-state CdZnTe calorimeter (for Compton absorption) and CsI calorimeter (for pair calorimetry), surrounded by a plastic scintillator anti-coincidence detector. Under the current proposal, we will complete the detailed design, assembly, and test of the CsI calorimeter for the risk

  6. Azobenzene-functionalized carbon nanotubes as high-energy density solar thermal fuels.

    Science.gov (United States)

    Kolpak, Alexie M; Grossman, Jeffrey C

    2011-08-10

    Solar thermal fuels, which reversibly store solar energy in molecular bonds, are a tantalizing prospect for clean, renewable, and transportable energy conversion/storage. However, large-scale adoption requires enhanced energy storage capacity and thermal stability. Here we present a novel solar thermal fuel, composed of azobenzene-functionalized carbon nanotubes, with the volumetric energy density of Li-ion batteries. Our work also demonstrates that the inclusion of nanoscale templates is an effective strategy for design of highly cyclable, thermally stable, and energy-dense solar thermal fuels.

  7. Quasiparticles in a diffusive conductor: interaction and pairing

    International Nuclear Information System (INIS)

    Gueron, S.

    1997-01-01

    The interaction between quasi particles is studied both theoretically and experimentally. The first part of this thesis is to provide direct evidence for this interaction by measuring the energy exchange rate between quasi particles in the case of thin metallic diffusive films. The experimental results agree qualitatively with the existing theories but are not explained quantitatively. The second part of this thesis deals with the propagation of correlation of pairs of electrons with opposite spin in a normal metal when it is placed in contact with a superconductor. This proximity effect is studied by measuring the density of states. The aim of the experiments is to specify in what sense a normal metal in proximity with a superconductor develops a superconducting character. (A.C.)

  8. Quasiparticles in a diffusive conductor: interaction and pairing

    Energy Technology Data Exchange (ETDEWEB)

    Gueron, S

    1997-10-17

    The interaction between quasi particles is studied both theoretically and experimentally. The first part of this thesis is to provide direct evidence for this interaction by measuring the energy exchange rate between quasi particles in the case of thin metallic diffusive films. The experimental results agree qualitatively with the existing theories but are not explained quantitatively. The second part of this thesis deals with the propagation of correlation of pairs of electrons with opposite spin in a normal metal when it is placed in contact with a superconductor. This proximity effect is studied by measuring the density of states. The aim of the experiments is to specify in what sense a normal metal in proximity with a superconductor develops a superconducting character. (A.C.) 102 refs.

  9. Pair truncation for rotational nuclei: j=17/2 model

    International Nuclear Information System (INIS)

    Halse, P.; Jaqua, L.; Barrett, B.R.

    1989-01-01

    The suitability of the pair condensate approach for rotational states is studied in a single j=17/2 shell of identical nucleons interacting through a quadrupole-quadrupole Hamiltonian. The ground band and a K=2 excited band are both studied in detail. A direct comparison of the exact states with those constituting the SD and SDG subspaces is used to identify the important degrees of freedom for these levels. The range of pairs necessary for a good description is found to be highly state dependent; S and D pairs are the major constituents of the low-spin ground-band levels, while G pairs are needed for those in the γ band. Energy spectra are obtained for each truncated subspace. SDG pairs allow accurate reproduction of the binding energy and K=2 excitation energy, but still give a moment of inertia which is about 30% too small even for the lowest levels

  10. An Application of the Direct Coulomb Electron Pair Production Process to the Energy Measurement of the "VH-Group" in the "Knee" Region of the "All-Particle" Energy Spectrum

    Science.gov (United States)

    Derrickson, J. H.; Wu, J.; Christl, M. J.; Fountain, W. F.; Parnell, T. A.

    1999-01-01

    The "all-particle" cosmic ray energy spectrum appears to be exhibiting a significant change in the spectral index just above approximately 3000 TeV. This could indicate (1) a change in the propagation of the cosmic rays in the galactic medium, and/or (2) the upper limit of the supernova shock wave acceleration mechanism, and/or (3) a new source of high-energy cosmic rays. Air shower and JACEE data indicate the spectral change is associated with a composition change to a heavier element mixture whereas DICE does not indicate this. A detector concept will be presented that utilizes the energy dependence of the production of direct Coulomb electron-positron pairs by energetic heavy ions. Monte Carlo simulations of a direct electron pair detector consisting of Pb target foils interleaved with planes of 1-mm square scintillating optical fibers will be discussed. The goal is to design a large area, non-saturating instrument to measure the energy spectrum of the individual cosmic ray elements in the "VH-group" for energies greater than 10 TeV/nucleon.

  11. Dispersion correction derived from first principles for density functional theory and Hartree-Fock theory.

    Science.gov (United States)

    Guidez, Emilie B; Gordon, Mark S

    2015-03-12

    The modeling of dispersion interactions in density functional theory (DFT) is commonly performed using an energy correction that involves empirically fitted parameters for all atom pairs of the system investigated. In this study, the first-principles-derived dispersion energy from the effective fragment potential (EFP) method is implemented for the density functional theory (DFT-D(EFP)) and Hartree-Fock (HF-D(EFP)) energies. Overall, DFT-D(EFP) performs similarly to the semiempirical DFT-D corrections for the test cases investigated in this work. HF-D(EFP) tends to underestimate binding energies and overestimate intermolecular equilibrium distances, relative to coupled cluster theory, most likely due to incomplete accounting for electron correlation. Overall, this first-principles dispersion correction yields results that are in good agreement with coupled-cluster calculations at a low computational cost.

  12. Attained energy densities and neutral pion spectra in nucleus-nucleus collisions at 200 GeV/nucleon

    International Nuclear Information System (INIS)

    Plasil, F.; Albrecht, R.; Awes, T.C.

    1989-01-01

    The main goal of the CERN heavy-ion experiments is the search for an indication that the predicted state of deconfined quarks and gluons, the quark-gluon plasma (QGP), has been produced. The quantity most crucial to the probability of QGP formation is the thermalized energy density attained during the heavy-ion reaction. The amount of energy radiated transverse to the beam direction is the experimental quantity which is believed to be a measure of the amount of energy deposition in the reaction, and hence to reflect the energy density attained. In this presentation we consider the systematics of transverse energy production at CERN SPS energies, and we use the results to make estimates, under various assumptions, of attained energy densities. 18 refs., 2 figs

  13. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals.

    Science.gov (United States)

    Zhang, Y; Huang, S L; Wang, S; Zhao, W

    2016-05-01

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert-Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of wave detection signals.

  14. High Energy Density Li-Ion Batteries Designed for Low Temperature Applications, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The state-of-the-art Li-ion batteries do not fully meet the energy density, power density and safety requirements specified by NASA for future exploration missions....

  15. Local Fitting of the Kohn-Sham Density in a Gaussian and Plane Waves Scheme for Large-Scale Density Functional Theory Simulations.

    Science.gov (United States)

    Golze, Dorothea; Iannuzzi, Marcella; Hutter, Jürg

    2017-05-09

    A local resolution-of-the-identity (LRI) approach is introduced in combination with the Gaussian and plane waves (GPW) scheme to enable large-scale Kohn-Sham density functional theory calculations. In GPW, the computational bottleneck is typically the description of the total charge density on real-space grids. Introducing the LRI approximation, the linear scaling of the GPW approach with respect to system size is retained, while the prefactor for the grid operations is reduced. The density fitting is an O(N) scaling process implemented by approximating the atomic pair densities by an expansion in one-center fit functions. The computational cost for the grid-based operations becomes negligible in LRIGPW. The self-consistent field iteration is up to 30 times faster for periodic systems dependent on the symmetry of the simulation cell and on the density of grid points. However, due to the overhead introduced by the local density fitting, single point calculations and complete molecular dynamics steps, including the calculation of the forces, are effectively accelerated by up to a factor of ∼10. The accuracy of LRIGPW is assessed for different systems and properties, showing that total energies, reaction energies, intramolecular and intermolecular structure parameters are well reproduced. LRIGPW yields also high quality results for extended condensed phase systems such as liquid water, ice XV, and molecular crystals.

  16. High Density Thermal Energy Storage with Supercritical Fluids

    Science.gov (United States)

    Ganapathi, Gani B.; Wirz, Richard

    2012-01-01

    A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

  17. Effects of energy content and energy density of pre-portioned entrées on energy intake.

    Science.gov (United States)

    Blatt, Alexandria D; Williams, Rachel A; Roe, Liane S; Rolls, Barbara J

    2012-10-01

    Pre-portioned entrées are commonly consumed to help control portion size and limit energy intake. The influence of entrée characteristics on energy intake, however, has not been well studied. We determined how the effects of energy content and energy density (ED, kcal/g) of pre-portioned entrées combine to influence daily energy intake. In a crossover design, 68 non-dieting adults (28 men and 40 women) were provided with breakfast, lunch, and dinner on 1 day a week for 4 weeks. Each meal included a compulsory, manipulated pre-portioned entrée followed by a variety of unmanipulated discretionary foods that were consumed ad libitum. Across conditions, the entrées were varied in both energy content and ED between a standard level (100%) and a reduced level (64%). Results showed that in men, decreases in the energy content and ED of pre-portioned entrées acted independently and added together to reduce daily energy intake (both P kcal/day; P lunch, but at dinner and for the entire day the effects depended on the interaction of the two factors (P daily energy intake in women by 14% (289 ± 35 kcal/day; P daily energy intake and could influence the effectiveness of such foods for weight management.

  18. New class of two-dimensional bimetallic nanoplatelets for high energy density and electrochemically stable hybrid supercapacitors

    DEFF Research Database (Denmark)

    Liu, Zhiting; Ma, Peng; Ulstrup, Jens

    2017-01-01

    Currently, the application of supercapacitors (SCs) in portable electronic devices and vehicles is limited by their low energy density. Developing high-energy density SCs without sacrificing their advantages, such as their long-term stability and high power density, has thus become an increasing...... and a 96.1% retention of the initial capacitance over 5,000 cycles. We exploited the novel 2D nanoplatelets as cathode materials to assemble a hybrid SC for full-cell tests. The resulting SCs operated in a wide potential window of 0 - 1.7 V, exhibited a high energy density over 50 Wh·kg-1, and sustained...

  19. Addendum to ''Density fluctuations in liquid rubidium''

    International Nuclear Information System (INIS)

    Haan, S.W.; Mountain, R.D.; Hsu, C.S.; Rahman, A.

    1980-01-01

    We performed molecular-dynamics simulations of liquid rubidium and the Lennard-Jones fluid at several densities and temperatures, and of a system whose pair potential is the repulsive core of the rubidium potential. In all cases, propagating density fluctuations occurred in the rubidiumlike systems at much shorter wavelengths than in the Lennard-Jones system. This indicates that the repulsive part of the pair potential is the dominant factor in determining the relaxation of short-wavelength density fluctuations

  20. Ultrahigh-Energy Density Lithium-Ion Cable Battery Based on the Carbon-Nanotube Woven Macrofilms.

    Science.gov (United States)

    Wu, Ziping; Liu, Kaixi; Lv, Chao; Zhong, Shengwen; Wang, Qinghui; Liu, Ting; Liu, Xianbin; Yin, Yanhong; Hu, Yingyan; Wei, Di; Liu, Zhongfan

    2018-05-01

    Moore's law predicts the performance of integrated circuit doubles every two years, lasting for more than five decades. However, the improvements of the performance of energy density in batteries lag far behind that. In addition, the poor flexibility, insufficient-energy density, and complexity of incorporation into wearable electronics remain considerable challenges for current battery technology. Herein, a lithium-ion cable battery is invented, which is insensitive to deformation due to its use of carbon nanotube (CNT) woven macrofilms as the charge collectors. An ultrahigh-tap density of 10 mg cm -2 of the electrodes can be obtained, which leads to an extremely high-energy density of 215 mWh cm -3 . The value is approximately seven times than that of the highest performance reported previously. In addition, the battery displays very stable rate performance and lower internal resistance than conventional lithium-ion batteries using metal charge collectors. Moreover, it demonstrates excellent convenience for connecting electronics as a new strategy is applied, in which both electrodes can be integrated into one end by a CNT macrorope. Such an ultrahigh-energy density lithium-ion cable battery provides a feasible way to power wearable electronics with commercial viability. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Note: A high-energy-density Tesla-type pulse generator with novel insulating oil

    Science.gov (United States)

    Liu, Sheng; Su, Jiancang; Fan, Xuliang

    2017-09-01

    A 10-GW high-energy-density Tesla-type pulse generator is developed with an improved insulating liquid based on a modified Tesla pulser—TPG700, of which the pulse forming line (PFL) is filled with novel insulating oil instead of transformer oil. Properties of insulating oil determining the stored energy density of the PFL are analyzed, and a criterion for appropriate oil is proposed. Midel 7131 is chosen as an application example. The results of insulating property experiment under tens-of-microsecond pulse charging demonstrate that the insulation capability of Midel 7131 is better than that of KI45X transformer oil. The application test in Tesla pulser TPG700 shows that the output power is increased to 10.5 GW with Midel 7131. The output energy density of TPG700 increases for about 60% with Midel 7131.

  2. Determination of the pairing-strength constants in the isovector plus isoscalar pairing case

    Science.gov (United States)

    Mokhtari, D.; Fellah, M.; Allal, N. H.

    2016-05-01

    A method for the determination of the pairing-strength constants, in the neutron-proton (n-p) isovector plus isoscalar pairing case, is proposed in the framework of the BCS theory. It is based on the fitting of these constants to reproduce the experimentally known pairing gap parameters as well as the root-mean-squared (r.m.s) charge radii values. The method is applied to some proton-rich even-even nuclei. The single-particle energies used are those of a deformed Woods-Saxon mean field. It is shown that the obtained value of the ratio GnpT=0/G npT=1 is of the same order as the ones, arbitrary chosen, of some previous works. The effect of the inclusion of the isoscalar n-p pairing in the r.m.s matter radii is then numerically studied for the same nuclei.

  3. Mechanical confinement for improved energy storage density in BNT-BT-KNN lead-free ceramic capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Aditya; Patel, Satyanarayan; Vaish, Rahul, E-mail: rahul@iitmandi.ac.in [School of Engineering, Indian Institute of Technology Mandi, 175 001 (India)

    2014-08-15

    With the advent of modern power electronics, embedded circuits and non-conventional energy harvesting, the need for high performance capacitors is bound to become indispensible. The current state-of-art employs ferroelectric ceramics and linear dielectrics for solid state capacitance. However, lead-free ferroelectric ceramics propose to offer significant improvement in the field of electrical energy storage owing to their high discharge efficiency and energy storage density. In this regards, the authors have investigated the effects of compressive stress as a means of improving the energy storage density of lead-free ferroelectric ceramics. The energy storage density of 0.91(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.07BaTiO{sub 3}-0.02(K{sub 0.5}Na{sub 0.5})NbO{sub 3} ferroelectric bulk ceramic was analyzed as a function of varying levels of compressive stress and operational temperature .It was observed that a peak energy density of 387 mJ.cm{sup -3} was obtained at 100 MPa applied stress (25{sup o}C). While a maximum energy density of 568 mJ.cm{sup -3} was obtained for the same stress at 80{sup o}C. These values are indicative of a significant, 25% and 84%, improvement in the value of stored energy compared to an unloaded material. Additionally, material's discharge efficiency has also been discussed as a function of operational parameters. The observed phenomenon has been explained on the basis of field induced structural transition and competitive domain switching theory.

  4. Density-functional theory based on the electron distribution on the energy coordinate

    Science.gov (United States)

    Takahashi, Hideaki

    2018-03-01

    We developed an electronic density functional theory utilizing a novel electron distribution n(ɛ) as a basic variable to compute ground state energy of a system. n(ɛ) is obtained by projecting the electron density n({\\boldsymbol{r}}) defined on the space coordinate {\\boldsymbol{r}} onto the energy coordinate ɛ specified with the external potential {\\upsilon }ext}({\\boldsymbol{r}}) of interest. It was demonstrated that the Kohn-Sham equation can also be formulated with the exchange-correlation functional E xc[n(ɛ)] that employs the density n(ɛ) as an argument. It turned out an exchange functional proposed in our preliminary development suffices to describe properly the potential energies of several types of chemical bonds with comparable accuracies to the corresponding functional based on local density approximation. As a remarkable feature of the distribution n(ɛ) it inherently involves the spatially non-local information of the exchange hole at the bond dissociation limit in contrast to conventional approximate functionals. By taking advantage of this property we also developed a prototype of the static correlation functional E sc including no empirical parameters, which showed marked improvements in describing the dissociations of covalent bonds in {{{H}}}2,{{{C}}}2{{{H}}}4 and {CH}}4 molecules.

  5. Modern foraging: Presence of food and energy density influence motivational processing of food advertisements.

    Science.gov (United States)

    Bailey, Rachel L

    2016-12-01

    More energy dense foods are preferable from an optimal foraging perspective, which suggests these foods are more motivationally relevant due to their greater capability of fulfilling biological imperatives. This increase in motivational relevance may be exacerbated in circumstances where foraging will be necessary. This study examined how food energy density and presence of food in the immediate environment interacted to influence motivational processing of food advertisements. N = 58 adults viewed advertisements for foods varying in energy density in contexts where the advertised food was actually present in the viewing room or not. Advertisements for more energy dense foods elicited greater skin conductivity level compared to ads for less energy dense foods when food was not present. All ads elicited decreases in corrugator supercilii activation indicating positive emotional response resultant from appetitive motivational activation, though the greatest activation was exhibited toward higher energy density foods when food was present. This supports an optimal foraging perspective and has implications for healthy eating interventions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Surface Andreev Bound States and Odd-Frequency Pairing in Topological Superconductor Junctions

    Science.gov (United States)

    Tanaka, Yukio; Tamura, Shun

    2018-04-01

    In this review, we summarize the achievement of the physics of surface Andreev bound states (SABS) up to now. The route of this activity has started from the physics of SABS of unconventional superconductors where the pair potential has a sign change on the Fermi surface. It has been established that SABS can be regarded as a topological edge state with topological invariant defined in the bulk Hamiltonian. On the other hand, SABS accompanies odd-frequency pairing like spin-triplet s-wave or spin-singlet p-wave. In a spin-triplet superconductor junction, induced odd-frequency pairing can penetrate into a diffusive normal metal (DN) attached to the superconductor. It causes so called anomalous proximity effect where the local density of states of quasiparticle in DN has a zero energy peak. When bulk pairing symmetry is spin-triplet px-wave, the anomalous proximity effect becomes prominent and the zero bias voltage conductance is always quantized independent of the resistance in DN and interface. Finally, we show that the present anomalous proximity effect is realized in an artificial topological superconducting system, where a nanowire with spin-orbit coupling and Zeeman field is put on the conventional spin-singlet s-wave superconductor.

  7. Hybrid TLC-pair meter for the Sphinx Project

    Science.gov (United States)

    Wada, T.; Yamamoto, I.; Takahashi, N.; Misaki, A.

    1985-01-01

    The chief aims in THE SPHINX PROJECT are research of super lepton physics and new detector experiments. At the second phase of THE SPHINX PROJECT, a hybrid TLC-PAIR METER was designed for measuring high energy neutrino sources (E upsilon * TeV), searching high energy muon sources (E mu TeV) and measuring muon group (E mu 1 TeV). The principle of PAIR METER has been already proposed. In this TLC-PAIR METER, electromagnetic shower induced by cosmic ray muons are detected using TL (Thermoluminescence) sheets with position counters.

  8. Hybrid TLC-pair meter for the Sphinx Project

    International Nuclear Information System (INIS)

    Wada, T.; Yamamoto, I.; Takahashi, N.; Misaki, A.

    1985-01-01

    The chief aims in the Sphinx Project are research on super lepton physics and new detector experiments. In the second phase of the Sphinx Project, a hybrid TLC-pair meter was designed for measuring for high energy neutrino sources (E upsilon * TeV), searching high energy muon sources (E mu TeV), and measuring muon groups (E mu 1 TeV). The principle of the pair meter has been already proposed. In this TLC pair meter, electromagnetic showers induced by cosmic ray muons are detected using thermoluminescene sheets with position counters

  9. Frontiers in pulse-power-based high energy density plasma physics and its applications

    International Nuclear Information System (INIS)

    Horioka, Kazuhiko

    2008-03-01

    The papers in this volume of report were presented at the Symposium on Frontiers in Pulse-power-based High Energy Density Physics' held by National Institute for Fusion Science. The topics include the present status of high energy density plasma researches, extreme ultraviolet sources, intense radiation sources, high power ion beams, and R and D of related pulse power technologies. The 13 of the presented papers are indexed individually. (J.P.N.)

  10. Structural change of cooper pairs in color superconductivity. Crossover from weak coupling to strong coupling

    Energy Technology Data Exchange (ETDEWEB)

    Abuki, Hiroaki; Hatsuda, Tetsuo [Tokyo Univ., Dept. of Physics, Tokyo (Japan); Itakura, Kazunori [Brookhaven National Laboratory, RIKEN BNL Research Center, Upton, NY (United States)

    2002-09-01

    The two-flavor color superconductivity is studied over a wide range of baryon density with a single model. We pay a special attention to the spatial-momentum dependence of the gap and to the spatial-structure of Cooper pairs. At extremely high baryon density ({approx}O(10{sup 10} {rho}{sub 0}) with {rho}{sub 0} being the normal nuclear matter density), our model becomes equivalent to the usual perturbative QCD treatment and the gap is shown to have a sharp peak near the Fermi surface due to the weak-coupling nature of QCD. On the other hand, the gap is a smooth function of the momentum at lower densities ({approx}O(10{sup 10} {rho}{sub 0})) due to strong color magnetic and electric interactions. To study the structural change of Cooper pairs from high density to lower density, quark correlation in the color superconductor is studied both in the momentum space and in the coordinate space. The size of the Cooper pair is shown to become comparable to the averaged inter-quark distance at low densities. Also, effects of the momentum-dependent running coupling and the antiquark pairing, which are both small at high density, are shown to be non-negligible at low densities. These features are highly contrasted to the standard BCS superconductivity in metals. (author)

  11. Ultrathin Coaxial Fiber Supercapacitors Achieving High Energy and Power Densities.

    Science.gov (United States)

    Shen, Caiwei; Xie, Yingxi; Sanghadasa, Mohan; Tang, Yong; Lu, Longsheng; Lin, Liwei

    2017-11-15

    Fiber-based supercapacitors have attracted significant interests because of their potential applications in wearable electronics. Although much progress has been made in recent years, the energy and power densities, mechanical strength, and flexibility of such devices are still in need of improvement for practical applications. Here, we demonstrate an ultrathin microcoaxial fiber supercapacitor (μCFSC) with high energy and power densities (2.7 mW h/cm 3 and 13 W/cm 3 ), as well as excellent mechanical properties. The prototype with the smallest reported overall diameter (∼13 μm) is fabricated by successive coating of functional layers onto a single micro-carbon-fiber via a scalable process. Combining the simulation results via the electrochemical model, we attribute the high performance to the well-controlled thin coatings that make full use of the electrode materials and minimize the ion transport path between electrodes. Moreover, the μCFSC features high bending flexibility and large tensile strength (more than 1 GPa), which make it promising as a building block for various flexible energy storage applications.

  12. Range-separated density-functional theory for molecular excitation energies

    International Nuclear Information System (INIS)

    Rebolini, E.

    2014-01-01

    Linear-response time-dependent density-functional theory (TDDFT) is nowadays a method of choice to compute molecular excitation energies. However, within the usual adiabatic semi-local approximations, it is not able to describe properly Rydberg, charge-transfer or multiple excitations. Range separation of the electronic interaction allows one to mix rigorously density-functional methods at short range and wave function or Green's function methods at long range. When applied to the exchange functional, it already corrects most of these deficiencies but multiple excitations remain absent as they need a frequency-dependent kernel. In this thesis, the effects of range separation are first assessed on the excitation energies of a partially-interacting system in an analytic and numerical study in order to provide guidelines for future developments of range-separated methods for excitation energy calculations. It is then applied on the exchange and correlation TDDFT kernels in a single-determinant approximation in which the long-range part of the correlation kernel vanishes. A long-range frequency-dependent second-order correlation kernel is then derived from the Bethe-Salpeter equation and added perturbatively to the range-separated TDDFT kernel in order to take into account the effects of double excitations. (author)

  13. Neutron stars as probes of extreme energy density matter

    Indian Academy of Sciences (India)

    2015-05-07

    May 7, 2015 ... Neutron stars have long been regarded as extraterrestrial laboratories from which we can learn about extreme energy density matter at low temperatures. In this article, some of the recent advances made in astrophysical observations and related theory are highlighted. Although the focus is on the much ...

  14. Pairing theory of high and low temperature superconductors

    International Nuclear Information System (INIS)

    Nam, Sang Boo

    1997-01-01

    A scenario which can account for all observed features of both high-Tc superconductors (HTS) and low-Tc superconductors (LTS) is discussed. This scenario is based on the fact that a finite pairing interaction energy range Td is required to have a finite value of Tc and that not all carriers participate in pairings, yielding multiconnected superconductors (MS). A new density of states, derived by keeping the order parameter zero outside of Td, is shown to account for the observed low energy states in HTS and for the temperature dependences in the specific heat, the penetration depth, the optical conductivity, and the tunneling conductance data. I argue that the notion of MS can account for the tunneling data along the a(or b)-, ab-, and c-axis, and the 1/2 flux quantum observed in HTS. The region occupied by unpaired carriers can be considered as a vortex with a fluxoid quantum number equal to 1 (VF), 0 (VZF), or -1 (VAF) when the magnetic flux around the vortex is greater than, equal to, or less than the effective flux produced by the supercurrent, respectively. The Hall anomaly depends on the relative strengths of the contributions via VF and VAF. The fact that the present scenario can account for all observed features of HTS and LTS suggests that the symmetry of the order parameter in HTS may not be different from one in LTS. (author)

  15. Lower Bound on the Energy Density in Classical and Quantum Field Theories.

    Science.gov (United States)

    Wall, Aron C

    2017-04-14

    A novel method for deriving energy conditions in stable field theories is described. In a local classical theory with one spatial dimension, a local energy condition always exists. For a relativistic field theory, one obtains the dominant energy condition. In a quantum field theory, there instead exists a quantum energy condition, i.e., a lower bound on the energy density that depends on information-theoretic quantities. Some extensions to higher dimensions are briefly discussed.

  16. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y., E-mail: thuzhangyu@foxmail.com; Huang, S. L., E-mail: huangsling@tsinghua.edu.cn; Wang, S.; Zhao, W. [State Key Laboratory of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084 (China)

    2016-05-15

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert–Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of <1% and thus can act as a universal time-of-flight extraction method for narrowband Lamb wave detection signals.

  17. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals

    International Nuclear Information System (INIS)

    Zhang, Y.; Huang, S. L.; Wang, S.; Zhao, W.

    2016-01-01

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert–Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of <1% and thus can act as a universal time-of-flight extraction method for narrowband Lamb wave detection signals.

  18. A physically motivated sparse cubature scheme with applications to molecular density-functional theory

    International Nuclear Information System (INIS)

    Rodriguez, Juan I; Thompson, David C; Anderson, James S M; Thomson, Jordan W; Ayers, Paul W

    2008-01-01

    We present a novel approach for performing multi-dimensional integration of arbitrary functions. The method starts with Smolyak-type sparse grids as cubature formulae on the unit cube and uses a transformation of coordinates based on the conditional distribution method to adapt those formulae to real space. Our method is tested on integrals in one, two, three and six dimensions. The three dimensional integration formulae are used to evaluate atomic interaction energies via the Gordon-Kim model. The six dimensional integration formulae are tested in conjunction with the nonlocal exchange-correlation energy functional proposed by Lee and Parr. This methodology is versatile and powerful; we contemplate application to frozen-density embedding, next-generation molecular-mechanics force fields, 'kernel-type' exchange-correlation energy functionals and pair-density functional theory

  19. Transformation of the superconducting gap to an insulating pseudogap at a critical hole density in the cuprates

    Science.gov (United States)

    Liu, Ye-Hua; Wang, Wan-Sheng; Wang, Qiang-Hua; Zhang, Fu-Chun; Rice, T. M.

    2017-07-01

    We apply the recent wave-packet formalism developed by Ossadnik to describe the origin of the short-range ordered pseudogap state as the hole doping is lowered through a critical density in cuprates. We argue that the energy gain that drives this precursor state to Mott localization, follows from maximizing umklapp scattering near the Fermi energy. To this end, we show how energy gaps driven by umklapp scattering can open on an appropriately chosen surface, as proposed earlier by Yang, Rice, and Zhang. The key feature is that the pairing instability includes umklapp scattering, leading to an energy gap not only in the single-particle spectrum but also in the pair spectrum. As a result the superconducting gap at overdoping is turned into an insulating pseudogap in the antinodal parts of the Fermi surface.

  20. Structural variability and the nature of intermolecular interactions in Watson-Crick B-DNA base pairs.

    Science.gov (United States)

    Czyznikowska, Z; Góra, R W; Zaleśny, R; Lipkowski, P; Jarzembska, K N; Dominiak, P M; Leszczynski, J

    2010-07-29

    A set of nearly 100 crystallographic structures was analyzed using ab initio methods in order to verify the effect of the conformational variability of Watson-Crick guanine-cytosine and adenine-thymine base pairs on the intermolecular interaction energy and its components. Furthermore, for the representative structures, a potential energy scan of the structural parameters describing mutual orientation of the base pairs was carried out. The results were obtained using the hybrid variational-perturbational interaction energy decomposition scheme. The electron correlation effects were estimated by means of the second-order Møller-Plesset perturbation theory and coupled clusters with singles and doubles method adopting AUG-cc-pVDZ basis set. Moreover, the characteristics of hydrogen bonds in complexes, mimicking those appearing in B-DNA, were evaluated using topological analysis of the electron density. Although the first-order electrostatic energy is usually the largest stabilizing component, it is canceled out by the associated exchange repulsion in majority of the studied crystallographic structures. Therefore, the analyzed complexes of the nucleic acid bases appeared to be stabilized mainly by the delocalization component of the intermolecular interaction energy which, in terms of symmetry adapted perturbation theory, encompasses the second- and higher-order induction and exchange-induction terms. Furthermore, it was found that the dispersion contribution, albeit much smaller in terms of magnitude, is also a vital stabilizing factor. It was also revealed that the intermolecular interaction energy and its components are strongly influenced by four (out of six) structural parameters describing mutual orientation of bases in Watson-Crick pairs, namely shear, stagger, stretch, and opening. Finally, as a part of a model study, much of the effort was devoted to an extensive testing of the UBDB databank. It was shown that the databank quite successfully reproduces the

  1. Coulomb displacement energies and neutron density distributions

    International Nuclear Information System (INIS)

    Shlomo, S.

    1979-01-01

    We present a short review of the present status of the theory of Coulomb displacement energies, ΔEsub(c), discussing the Okamoto-Nolem-Schiffer anomaly and its solution. We emphasize, in particular, that contrary to previous hopes, ΔEsub(c) does not determine rsub(ex), the root-mean square (rms) radius of the excess (valence) neutron density distribution. Instead, ΔEsub(c) is very sensitive to the value of Δr = rsub(n) - rsub(p), the difference between the rms radii of the density distributions of all neutrons and all protons. For neutron rich nuclei, such as 48 Ca and 208 Pb, a value of Δr = 0.1 fm is found to be consistent with ΔEsub(c). This value of Δr, which is considerably smaller than that (of 0.2 - 0.3 fm) predicted by some common Hartree-Fock calculations, seems to be confirmed by very recent experimental results. (orig.)

  2. Research and Evaluation of the Energy Flux Density of the Mobile Phone Electromagnetic Field

    Directory of Open Access Journals (Sweden)

    Pranas Baltrėnas

    2012-12-01

    Full Text Available The article analyses variations in the energy flux density of the electromagnetic field of 10 mobile phones depending on distance. The studies have been conducted using three modes: sending a text message, receiving a text message and connecting a mobile phone to the Internet. When text messages are received or sent from a mobile phone, the values of the energy flux density of the mobile phone electromagnetic field exceed the safe allowable limit and make 10 μW / cm². A distance of 10, 20 and 30 cm from a mobile phone is effective protection against the energy flux density of the electromagnetic field when writing texts, receiving messages or connecting to the mobile Internet.Article in Lithuanian

  3. Pion-pair formation and the pion dispersion relation in a hot pion gas

    Energy Technology Data Exchange (ETDEWEB)

    Chanfay, G. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Alm, T. [Rostock Univ. (Germany); Schuck, P. [Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires; Welke, G. [Wayne State Univ., Detroit, MI (United States). Dept. of Physics and Astronomy

    1996-09-01

    The possibility of pion-pair formation in a hot pion gas, based on the bosonic gap equation, is pointed out and discussed in detail. The critical temperature for condensation of pion pairs (Evans-Rashind transition) is determined as a function of the pion density. As for fermions, this phase transition is signaled by the appearance of a pole in the two-particle propagator. In Bose systems there exists a second, lower critical temperature, associated with the appearance of the single-particle condensate. Between the two critical temperatures the pion dispersion relation changes from the usual quasiparticle dispersion to a Bogoliubov-like dispersion relation at low momenta. This generalizes the non-relativistic results for an attractive Bose gas by Evans et al. Possible consequences for the inclusive pion spectra measured in heavy-ion collisions at ultra-relativistic energies are discussed. 21 refs.

  4. The Hagedorn spectrum, nuclear level densities and first order phase transitions

    International Nuclear Information System (INIS)

    Moretto, Luciano G.; Larsen, A. C.; Guttormsen, M.; Siem, S.

    2015-01-01

    An exponential mass spectrum, like the Hagedorn spectrum, with slope 1/T H was interpreted as fixing an upper limiting temperature T H that the system can achieve. However, thermodynamically, such spectrum indicates a 1 st order phase transition at a fixed temperature T H . A much lower energy example is the log linear level nuclear density below the neutron binding energy that prevails throughout the nuclear chart. We show that, for non-magic nuclei, such linearity implies a 1 st order phase transition from the pairing superfluid to an ideal gas of quasi particles

  5. Creating high energy density in nuclei with energetic antiparticles

    International Nuclear Information System (INIS)

    Gibbs, W.R.

    1986-01-01

    The possibility of creating a phase change in nuclear matter using energetic antiprotons and antideuterons is examined. It is found that energy densities of the order of 2 GeV/c can be obtained for periods of approx.2 fm/c with the proper experimental selection of events. 10 refs., 7 figs

  6. Short-term overeating results in incomplete energy intake compensation regardless of energy density or macronutrient composition.

    Science.gov (United States)

    Apolzan, John W; Bray, George A; Hamilton, Marc T; Zderic, Theodore W; Han, Hongmei; Champagne, Catherine M; Shepard, Desti; Martin, Corby K

    2014-01-01

    To evaluate the effects of overeating (140% of energy requirements) a high-fat low-energy density diet (HF/LED, 1.05 kcal/g), high-fat high-energy density diet (HF/HED, 1.60 kcal/g), and high-carbohydrate (HC) LED (1.05 kcal/g) for 2-days on subsequent 4-day energy intake (EI), activity levels, appetite, and mood. Using a randomized cross-over design, energy expenditure and EI were standardized during overeating. In 20 adults with a mean ± SD BMI of 30.7 ± 4.6 kg/m(2) , EI was not suppressed until the second day after overeating and accounted for ∼30% of the excess EI. Reductions in EI did not differ among the three diets or across days. Overeating had no effect on subsequent energy expenditure but steps/day decreased after the HC/LED and HF/HED. Sleep time was increased after the HF/HED compared to both LEDs. After overeating a HF/HED vs. HF/LED, carbohydrate cravings, hunger, prospective food consumption, and sadness increased and satisfaction, relaxation, and tranquility decreased. Diet type, time, or their interaction had no impact on compensation over 4 days. No adaptive thermogenesis was observed. The HF/HED vs. HF/LED had detrimental effects on food cravings, appetite, and mood. These results suggest short-term overeating is associated with incomplete compensation. Copyright © 2013 The Obesity Society.

  7. Frontiers for Discovery in High Energy Density Physics

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, R. C.; Katsouleas, T.; Arons, J.; Baring, M.; Deeney, C.; Di Mauro, L.; Ditmire, T.; Falcone, R.; Hammer, D.; Hill, W.; Jacak, B.; Joshi, C.; Lamb, F.; Lee, R.; Logan, B. G.; Melissinos, A.; Meyerhofer, D.; Mori, W.; Murnane, M.; Remington, B.; Rosner, R.; Schneider, D.; Silvera, I.; Stone, J.; Wilde, B.; Zajc. W.

    2004-07-20

    The report is intended to identify the compelling research opportunities of high intellectual value in high energy density physics. The opportunities for discovery include the broad scope of this highly interdisciplinary field that spans a wide range of physics areas including plasma physics, laser and particle beam physics, nuclear physics, astrophysics, atomic and molecular physics, materials science and condensed matter physics, intense radiation-matter interaction physics, fluid dynamics, and magnetohydrodynamics

  8. Application of an excited state LDA exchange energy functional for the calculation of transition energy of atoms within time-independent density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Shamim, Md; Harbola, Manoj K, E-mail: sami@iitk.ac.i, E-mail: mkh@iitk.ac.i [Department of Physics, Indian Institute of Technology, Kanpur 208 016 (India)

    2010-11-14

    Transition energies of a new class of excited states (two-gap systems) of various atoms are calculated in time-independent density functional formalism by using a recently proposed local density approximation exchange energy functional for excited states. It is shown that the excitation energies calculated with this functional compare well with those calculated with exact exchange theories.

  9. Application of an excited state LDA exchange energy functional for the calculation of transition energy of atoms within time-independent density functional theory

    International Nuclear Information System (INIS)

    Shamim, Md; Harbola, Manoj K

    2010-01-01

    Transition energies of a new class of excited states (two-gap systems) of various atoms are calculated in time-independent density functional formalism by using a recently proposed local density approximation exchange energy functional for excited states. It is shown that the excitation energies calculated with this functional compare well with those calculated with exact exchange theories.

  10. A High Power Density Single-Phase PWM Rectifier With Active Ripple Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruxi [Virginia Polytechnic Institute and State University (Virginia Tech); Wang, Fei [ORNL; Boroyevich, Dushan [Virginia Polytechnic Institute and State University (Virginia Tech); Burgos, Rolando [ABB; Lai, Rixin [General Electric; Ning, Puqi [ORNL; Rajashekara, Kaushik [Rolls Royce

    2011-01-01

    It is well known that single-phase pulse width modulation rectifiers have second-order harmonic currents and corresponding ripple voltages on the dc bus. The low-frequency harmonic current is normally filtered using a bulk capacitor in the bus, which results in low power density. However, pursuing high power density in converter design is a very important goal in the aerospace applications. This paper studies methods for reducing the energy storage capacitor for single-phase rectifiers. The minimum ripple energy storage requirement is derived independently of a specific topology. Based on theminimum ripple energy requirement, the feasibility of the active capacitor s reduction schemes is verified. Then, we propose a bidirectional buck boost converter as the ripple energy storage circuit, which can effectively reduce the energy storage capacitance. The analysis and design are validated by simulation and experimental results.

  11. An interface energy density-based theory considering the coherent interface effect in nanomaterials

    Science.gov (United States)

    Yao, Yin; Chen, Shaohua; Fang, Daining

    2017-02-01

    To characterize the coherent interface effect conveniently and feasibly in nanomaterials, a continuum theory is proposed that is based on the concept of the interface free energy density, which is a dominant factor affecting the mechanical properties of the coherent interface in materials of all scales. The effect of the residual strain caused by self-relaxation and the lattice misfit of nanomaterials, as well as that due to the interface deformation induced by an external load on the interface free energy density is considered. In contrast to the existing theories, the stress discontinuity at the interface is characterized by the interface free energy density through an interface-induced traction. As a result, the interface elastic constant introduced in previous theories, which is not easy to determine precisely, is avoided in the present theory. Only the surface energy density of the bulk materials forming the interface, the relaxation parameter induced by surface relaxation, and the mismatch parameter for forming a coherent interface between the two surfaces are involved. All the related parameters are far easier to determine than the interface elastic constants. The effective bulk and shear moduli of a nanoparticle-reinforced nanocomposite are predicted using the proposed theory. Closed-form solutions are achieved, demonstrating the feasibility and convenience of the proposed model for predicting the interface effect in nanomaterials.

  12. Energy gap in S- and D-wave pairing superconductors

    International Nuclear Information System (INIS)

    Dolgov, O.V.; Golubov, A.A.

    1988-01-01

    In this paper the ratio of 2Δ g /T c , where Δ g is the gap edge, T c is the critical temperature, is calculated in the framework of the model of strong electron-phonon coupling. Both isotropic and anisotropic pairing cases are considered. It is shown that the isotropic Eliashberg model can not account for the large values of the ratio 2Δ g /T c for the reasonable values of the electron-phonon coupling parameter λ while anisotropic pairing can resolve this problem

  13. Energy Density, Energy Intake, and Body Weight Regulation in Adults12345

    Science.gov (United States)

    Karl, J. Philip; Roberts, Susan B.

    2014-01-01

    The role of dietary energy density (ED) in the regulation of energy intake (EI) is controversial. Methodologically, there is also debate about whether beverages should be included in dietary ED calculations. To address these issues, studies examining the effects of ED on EI or body weight in nonelderly adults were reviewed. Different approaches to calculating dietary ED do not appear to alter the direction of reported relations between ED and body weight. Evidence that lowering dietary ED reduces EI in short-term studies is convincing, but there are currently insufficient data to determine long-term effectiveness for weight loss. The review also identified key barriers to progress in understanding the role of ED in energy regulation, in particular the absence of a standard definition of ED, and the lack of data from multiple long-term clinical trials examining the effectiveness of low-ED diet recommendations for preventing both primary weight gain and weight regain in nonobese individuals. Long-term clinical trials designed to examine the impact of dietary ED on energy regulation, and including multiple ED calculation methods within the same study, are still needed to determine the importance of ED in the regulation of EI and body weight. PMID:25398750

  14. Frontiers of particle beam and high energy density plasma science using pulse power technology

    International Nuclear Information System (INIS)

    Masugata, Katsumi

    2011-04-01

    The papers presented at the symposium on “Frontiers of Particle Beam and High Energy Density Plasma Science using Pulse Power Technology” held in November 20-21, 2009 at National Institute for Fusion Science are collected. The papers reflect the present status and resent progress in the experiment and theoretical works on high power particle beams and high energy density plasmas produced by pulsed power technology. (author)

  15. Strongly Interacting Matter at Very High Energy Density

    International Nuclear Information System (INIS)

    McLerran, L.

    2011-01-01

    The authors discuss the study of matter at very high energy density. In particular: what are the scientific questions; what are the opportunities to makes significant progress in the study of such matter and what facilities are now or might be available in the future to answer the scientific questions? The theoretical and experimental study of new forms of high energy density matter is still very much a 'wild west' field. There is much freedom for developing new concepts which can have order one effects on the way we think about such matter. It is also a largely 'lawless' field, in that concepts and methods are being developed as new information is generated. There is also great possibility for new experimental discovery. Most of the exciting results from RHIC experiments were unanticipated. The methods used for studying various effects like flow, jet quenching, the ridge, two particle correlations etc. were developed as experiments evolved. I believe this will continue to be the case at LHC and as we use existing and proposed accelerators to turn theoretical conjecture into tangible reality. At some point this will no doubt evolve into a precision science, and that will make the field more respectable, but for my taste, the 'wild west' times are the most fun.

  16. Projected entangled pair states: status and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Verstraete, Frank [Universitaet Wien (Austria)

    2008-07-01

    We report on the progress made to extend the density matrix renormalization group to higher dimensions, discuss the underlying theory of projected entangled pair states (PEPS) and illustrate its potential on the hand of a few examples.

  17. Cowichan Valley energy mapping and modelling. Report 5 - Energy density mapping projections. Final report. [Vancouver Island, Canada

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-06-15

    The driving force behind the Integrated Energy Mapping and Analysis project was the identification and analysis of a suite of pathways that the Cowichan Valley Regional District (CVRD) can utilise to increase its energy resilience, as well as reduce energy consumption and GHG emissions, with a primary focus on the residential sector. Mapping and analysis undertaken will support provincial energy and GHG reduction targets, and the suite of pathways outlined will address a CVRD internal target that calls for 75% of the region's energy within the residential sector to come from locally sourced renewables by 2050. The target has been developed as a mechanism to meet resilience and climate action target. The maps and findings produced are to be integrated as part of a regional policy framework currently under development. Task 5 focused on energy projection mapping to estimate and visualise the energy consumption density and GHG emissions under different scenarios. The scenarios from task 4 were built around the energy consumption density of the residential sector under future land use patterns and rely on different energy source combinations (the suite of pathways). In task 5 the energy usage under the different scenarios were fed back into GIS, thereby giving a visual representation of forecasted residential energy consumption per unit area. The methodology is identical to that used in task 2 where current usage was mapped, whereas the mapping in this task is for future forecasts. These results are documented in this report. In addition, GHG mapping under the various scenarios was also undertaken. (LN)

  18. Advanced Cathode Material For High Energy Density Lithium-Batteries, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced cathode materials having high red-ox potential and high specific capacity offer great promise to the development of high energy density lithium-based...

  19. Analysis of electronic models for solar cells including energy resolved defect densities

    Energy Technology Data Exchange (ETDEWEB)

    Glitzky, Annegret

    2010-07-01

    We introduce an electronic model for solar cells including energy resolved defect densities. The resulting drift-diffusion model corresponds to a generalized van Roosbroeck system with additional source terms coupled with ODEs containing space and energy as parameters for all defect densities. The system has to be considered in heterostructures and with mixed boundary conditions from device simulation. We give a weak formulation of the problem. If the boundary data and the sources are compatible with thermodynamic equilibrium the free energy along solutions decays monotonously. In other cases it may be increasing, but we estimate its growth. We establish boundedness and uniqueness results and prove the existence of a weak solution. This is done by considering a regularized problem, showing its solvability and the boundedness of its solutions independent of the regularization level. (orig.)

  20. Average Nuclear Level Densities and Radiative Strength Functions in 56,57FE from Primary (Gamma)-Ray Spectra

    International Nuclear Information System (INIS)

    Tavukcu, E.; Becker, J.A.; Bernstein, L.A.; Garrett, P.E.; Guttormsen, M.; Mitchell, G.E.; Rekstad, J.; Schiller, A.; Siem, S.; Voinov, A.; Younes, W.

    2002-01-01

    An experimental primary γ-ray spectrum vs. excitation-energy bin (P(E x , E γ ) matrix) in a light-ion reaction is obtained for 56,57 Fe isotopes using a subtraction method. By factorizing the P(E x , E γ ) matrix according to the Axel-Brink hypothesis the nuclear level density and the radiative strength function (RSF) in 56,57 Fe are extracted simultaneously. A step structure is observed in the level density for both isotopes, and is interpreted as the breaking of Cooper pairs. The RSFs for 56,57 Fe reveal an anomalous enhancement at low γ-ray energies

  1. U.S. Heavy Ion Beam Research for High Energy Density Physics Applications and Fusion

    International Nuclear Information System (INIS)

    Davidson, R.C.; Logan, B.G.; Barnard, J.J.; Bieniosek, F.M.; Briggs, R.J.

    2005-01-01

    Key scientific results from recent experiments, modeling tools, and heavy ion accelerator research are summarized that explore ways to investigate the properties of high energy density matter in heavy-ion-driven targets, in particular, strongly-coupled plasmas at 0.01 to 0.1 times solid density for studies of warm dense matter, which is a frontier area in high energy density physics. Pursuit of these near-term objectives has resulted in many innovations that will ultimately benefit heavy ion inertial fusion energy. These include: neutralized ion beam compression and focusing, which hold the promise of greatly improving the stage between the accelerator and the target chamber in a fusion power plant; and the Pulse Line Ion Accelerator (PLIA), which may lead to compact, low-cost modular linac drivers

  2. Jet pairing algorithm for the 6-jet Higgs channel via energy chi-square criterion

    International Nuclear Information System (INIS)

    Magallanes, J.B.; Arogancia, D.C.; Gooc, H.C.; Vicente, I.C.M.; Bacala, A.M.; Miyamoto, A.; Fujii, K.

    2002-01-01

    Study and discovery of the Higgs bosons at JLC (Joint Linear Collider) is one of the tasks of ACFA (Asian Committee for future Accelerators)-JLC Group. The mode of Higgs production at JLC is e + e - → Z 0 H 0 . In this paper, studies are concentrated on the Higgsstrahlung process and the selection of its signals by getting the right jet-pairing algorithm of 6-jet final state at 300 GeV assuming that Higgs boson mass is 120 GeV and luminosity is 500 fb -1 . The total decay width Γ (H 0 → all) and the efficiency of the signals at the JLC are studied utilizing the 6-jet channel. Out of the 91,500 Higgsstrahlung events, 4,174 6-jet events are selected. PYTHIA Monte Carlo Generator generates the 6-jet Higgsstrahlung channel according to the Standard Model. The generated events are then simulated by Quick Simulator using the JCL parameters. After tagging all 6 quarks which correspond to the 6-jet final state of the Higgsstrahlung, the mean energy of the Z, H, and W's are obtained. Having calculated these information, the event energy chi-square is defined and it is found that the correct combination have generally smaller value. This criterion can be used to find correct jet-pairing algorithm and as one of the cuts for the background signals later on. Other chi-definitions are also proposed. (S. Funahashi)

  3. Normal lumbar spine bone mineral densities with single-energy CT

    International Nuclear Information System (INIS)

    Hendrick, R.E.; Ritenour, E.R.; Geis, J.R.; Thickman, D.; Freeman, K.

    1988-01-01

    The authors report trabecular spine densities determined by single-energy CT in 267 healthy women, aged 22 to 75 years. Volunteers were scanned at eight sites with use of identical fourth-generation CT scanners, postpatient calibration phantoms, and analysis software that accounts for beam hardening as a function of patient size. Results indicate that a cubic polynomial best represents the decrease in bone density (in milligrams per milliliter of K 2 HPO 4 ) with age (in years): Bone Density = 140.9 + 4.44(Age) - 0.133(Age) 2 + 0.0008(Age) 3 , with statistical significance over the best linear and quadratic polynomial fits (P < .001). The mean bone densities of healthy women above age 30 years are found to be lower by an average of 8 mg/mL than reported by Cann et al, whose data indicate that the greatest loss in trabecular bone density in healthy women occurs in the 50-59-year group, while out data indicate greatest loss in the 60-75 year age group

  4. Thermodynamic and kinetic properties of hydrogen defect pairs in SrTiO3 from density functional theory

    DEFF Research Database (Denmark)

    Bork, Nicolai Christian; Bonanos, Nikolaos; Rossmeisl, Jan

    2011-01-01

    A density functional theory investigation of the thermodynamic and kinetic properties of hydrogen–hydrogen defect interactions in the cubic SrTiO3 perovskite is presented. We find a net attraction between two hydrogen atoms with an optimal separation of ∼2.3 Å. The energy gain is ca. 0.33 eV comp...

  5. Further test of new pairing scheme used in overhaul of BCS theory

    International Nuclear Information System (INIS)

    Zheng, X.H.; Walmsley, D.G.

    2014-01-01

    Highlights: • Explanation of a new pairing scheme to overhaul BCS theory. • Prediction of superconductor properties from normal state resistivity. • Applications to Nb, Pb, Al, Ta, Mo, Ir and W, T c between 9.5 and 0.012 K. • High accuracy compared with measured energy gap of Nb, Pb, Al and Ta. • Prediction of energy gap for Mo, Ir and W (so far not measured). - Abstract: A new electron pairing scheme, rectifying a fundamental flaw of the BCS theory, is tested extensively. It postulates that superconductivity arises solely from residual umklapp scattering when it is not in competition for the same destination electron states with normal scattering. It reconciles a long standing theoretical discrepancy in the strength of the electron–phonon interaction between the normal and superconductive states. The new scheme is exploited to calculate the superconductive electron–phonon spectral density, α 2 F(ν), entirely on the basis of normal state electrical resistivity. This leads to first principles superconductive properties (zero temperature energy gap and tunnelling conductance) in seven metals which turn out to be highly accurate when compared with known data; in other cases experimental verification is invited. The transition temperatures involved vary over almost three orders of magnitude: from 9.5 K for niobium to 0.012 K for tungsten

  6. Continuum corrections to the level density and its dependence on excitation energy, n-p asymmetry, and deformation

    International Nuclear Information System (INIS)

    Charity, R.J.; Sobotka, L.G.

    2005-01-01

    In the independent-particle model, the nuclear level density is determined from the neutron and proton single-particle level densities. The single-particle level density for the positive-energy continuum levels is important at high excitation energies for stable nuclei and at all excitation energies for nuclei near the drip lines. This single-particle level density is subdivided into compound-nucleus and gas components. Two methods are considered for this subdivision: In the subtraction method, the single-particle level density is determined from the scattering phase shifts. In the Gamov method, only the narrow Gamov states or resonances are included. The level densities calculated with these two methods are similar; both can be approximated by the backshifted Fermi-gas expression with level-density parameters that are dependent on A, but with very little dependence on the neutron or proton richness of the nucleus. However, a small decrease in the level-density parameter is predicted for some nuclei very close to the drip lines. The largest difference between the calculations using the two methods is the deformation dependence of the level density. The Gamov method predicts a very strong peaking of the level density at sphericity for high excitation energies. This leads to a suppression of deformed configurations and, consequently, the fission rate predicted by the statistical model is reduced in the Gamov method

  7. Density and energy distribution of epithermal secondary electrons in a plasma with fast charged particles

    International Nuclear Information System (INIS)

    Jayakumar, R.; Fleischmann, H.H.

    1989-01-01

    The production of intermediate energy secondary electrons in plasmas through collisions with fast charged particles is investigated. The density and the distribution of the secondary electrons are obtained by calculating the generation, slow down and diffusion rates, using basic Rutherford collision cross sections. It is shown that the total density of secondaries is much smaller than the fast particle density and that the energy distribution has roughly a 1/√E dependence. The higher generation secondary populations are also obtained. (orig.)

  8. The clinical determination of absolute density in bone utilizing single and dual energy compton scattering

    International Nuclear Information System (INIS)

    Huddleston, A.L.; Weaver, J.

    1980-01-01

    Several methods important in the clinical diagnosis of skeletal diseases have been proposed for the determination of bone mass, such as photon absorptiometry, computed tomography, and neutron activation. None of these present methods provides for the determination of the physical density of bone. In the Radiological Physics Research Laboratory at the University of Virginia, the principles of Compton scattering are being investigated with the intent of determining the electron density and the physical density of human bone. A Compton-scatter densitometer has been constructed for the in vivo density determination of the femoral head. This technique utilizes of collimated low energy gamma source and detector system. The method has been tested in cadavers and in known density samples and has an accuracy of 2 %. A second densitometer has been designed for the in vivo determination of electron density of the vertebrae based upon a new technique which employs dual energy Compton scattering in the spinal column. These systems will be discussed; and the principles of dual energy Compton scatter densitometry will be presented. The importance of these isotope techniques and the feasibility of in vivo density determination in the vertebrae and femoral head will be discussed as they relate to clinical diagnosis and research. (author)

  9. Arrays of Synthetic Atoms: Nanocapacitor Batteries with Large Energy Density and Small Leak Currents

    Science.gov (United States)

    2017-11-28

    AFRL-RV-PS- AFRL-RV-PS- TR-2017-0169 TR-2017-0169 ARRAYS OF SYNTHETIC ATOMS: NANOCAPACITOR BATTERIES WITH LARGE ENERGY DENSITY AND SMALL LEAK...1-0247 Arrays of Synthetic Atoms: Nanocapacitor Batteries with Large Energy Density and Small Leak Currents 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...large dielectric strength to a nanoscale rechargeable battery . We fabricated arrays of one-, two- and three-dimensional synthetic atoms and comparison

  10. Agglomeration of amorphous silicon film with high energy density excimer laser irradiation

    International Nuclear Information System (INIS)

    He Ming; Ishihara, Ryoichi; Metselaar, Wim; Beenakker, Kees

    2007-01-01

    In this paper, agglomeration phenomena of amorphous Si (α-Si) films due to high energy density excimer laser irradiation are systematically investigated. The agglomeration, which creates holes or breaks the continuous Si film up into spherical beads, is a type of serious damage. Therefore, it determines an upper energy limit for excimer laser crystallization. It is speculated that the agglomeration is caused by the boiling of molten Si. During this process, outbursts of heterogeneously nucleated vapor bubbles are promoted by the poor wetting property of molten silicon on the SiO 2 layer underneath. The onset of the agglomeration is defined by extrapolating the hole density as a function of the energy density of the laser pulse. A SiO 2 capping layer (CL) is introduced on top of the α-Si film to investigate its influence on the agglomeration. It is found that effects of the CL depend on its thickness. The CL with a thickness less than 300 nm can be used to suppress the agglomeration. A thin CL acts as a confining layer and puts a constraint on bubble burst, and hence suppresses the agglomeration

  11. Enhanced energy density of carbon-based supercapacitors using Cerium (III) sulphate as inorganic redox electrolyte

    International Nuclear Information System (INIS)

    Díaz, Patricia; González, Zoraida; Santamaría, Ricardo; Granda, Marcos; Menéndez, Rosa; Blanco, Clara

    2015-01-01

    Highlights: •Ce 2 (SO 4 ) 3 /H 2 SO 4 redox electrolyte as a new route to increase the energy density of SCs. •Increased operating cell voltage with no electrolyte decomposition. •Redox reactions on the battery-type electrode. •The negative electrode retains its capacitor behaviour. •Outstanding energy density values compared to those measured in H 2 SO 4 . -- ABSTRACT: The energy density of carbon based supercapacitors (CBSCs) was significantly increased by the addition of an inorganic redox species [Ce 2 (SO 4 ) 3 ] to an aqueous electrolyte (H 2 SO 4 ). The development of the faradaic processes on the positive electrode not only significantly increased the capacitance but also the operational cell voltage of these devices (up to 1.5 V) due to the high redox potentials at which the Ce 3+ /Ce 4+ reactions occur. Therefore, in asymmetric CBSCs assembled using an activated carbon as negative electrode and MWCNTs as the positive one, the addition of Ce 2 (SO 4 ) 3 moderately increases the energy density of the device (from 1.24 W h kg −1 to 5.08 W h kg −1 ). When a modified graphite felt is used as positive electrode the energy density of the cell reaches values as high as 13.84 W h kg −1 . The resultant systems become asymmetric hybrid devices where energy is stored due to the electrical double layer formation in the negative electrode and the development of the faradaic process in the positive electrode, which acts as a battery-type electrode

  12. THE PAIR BEAM PRODUCTION SPECTRUM FROM PHOTON-PHOTON ANNIHILATION IN COSMIC VOIDS

    Energy Technology Data Exchange (ETDEWEB)

    Schlickeiser, R.; Ibscher, D. [Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Elyiv, A. [Institut d' Astrophysique et de Geophysique, Universite de Liege, B-4000 Liege (Belgium); Miniati, F., E-mail: rsch@tp4.rub.de, E-mail: ibscher@tp4.rub.de, E-mail: elyiv@astro.ulg.ac.be, E-mail: fm@phys.ethz.ch [Physics Department, Wolfgang-Pauli-Strasse 27, ETH-Zuerich, CH-8093 Zuerich (Switzerland)

    2012-10-20

    Highly beamed relativistic e {sup {+-}}-pair energy distributions result in double photon collisions of the beamed gamma rays from TeV blazars at cosmological distances with the isotropically distributed extragalactic background light (EBL) in the intergalactic medium. The typical energies k {sub 0} {approx_equal} 10{sup -7} in units of m{sub e}c {sup 2} of the EBL are more than 10 orders of magnitude smaller than the observed gamma-ray energies k {sub 1} {>=} 10{sup 7}. Using the limit k {sub 0} << k {sub 1}, we demonstrate that the angular distribution of the generated pairs in the lab frame is highly beamed in the direction of the initial gamma-ray photons. For the astrophysically important case of power-law distributions of the emitted gamma-ray beam up to the maximum energy M interacting with Wien-type N(k {sub 0}){proportional_to}k{sup q} {sub 0}exp (- k {sub 0}/{Theta}) soft photon distributions with total number density N {sub 0}, we calculate analytical approximations for the electron production spectrum. For distant objects with luminosity distances d{sub L} >> r {sub 0} = ({sigma} {sub T} N {sub 0}){sup -1} = 0.49N {sup -1} {sub 0} Mpc (with Thomson cross section {sigma} {sub T}), the implied large values of the optical depth {tau}{sub 0} = d{sub L} /r {sub 0} indicate that the electron production spectra differ at energies inside and outside the interval [({Theta}ln {tau}{sub 0}){sup -1}, {tau}{sub 0}/{Theta}], given the maximum gamma-ray energy M >> {Theta}{sup -1}. In the case M >> {Theta}{sup -1}, the production spectrum is strongly peaked near E {approx_equal} {Theta}{sup -1}, being exponentially reduced at small energies and decreasing with the steep power law {proportional_to}E {sup -1-p} up to the maximum energy E = M - (1/2).

  13. Testing DARKexp against energy and density distributions of Millennium-II halos

    Energy Technology Data Exchange (ETDEWEB)

    Nolting, Chris; Williams, Liliya L.R. [School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN, 55454 (United States); Boylan-Kolchin, Michael [Department of Astronomy, The University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX, 78712 (United States); Hjorth, Jens, E-mail: nolting@astro.umn.edu, E-mail: llrw@astro.umn.edu, E-mail: mbk@astro.as.utexas.edu, E-mail: jens@dark-cosmology.dk [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, Copenhagen, DK-2100 Denmark (Denmark)

    2016-09-01

    We test the DARKexp model for relaxed, self-gravitating, collisionless systems against equilibrium dark matter halos from the Millennium-II simulation. While limited tests of DARKexp against simulations and observations have been carried out elsewhere, this is the first time the testing is done with a large sample of simulated halos spanning a factor of ∼ 50 in mass, and using independent fits to density and energy distributions. We show that DARKexp, a one shape parameter family, provides very good fits to the shapes of density profiles, ρ( r ), and differential energy distributions, N ( E ), of individual simulated halos. The best fit shape parameter φ{sub 0} obtained from the two types of fits are correlated, though with scatter. Our most important conclusions come from ρ( r ) and N ( E ) that have been averaged over many halos. These show that the bulk of the deviations between DARKexp and individual Millennium-II halos come from halo-to-halo fluctuations, likely driven by substructure, and other density perturbations. The average ρ( r ) and N ( E ) are quite smooth and follow DARKexp very closely. The only deviation that remains after averaging is small, and located at most bound energies for N ( E ) and smallest radii for ρ( r ). Since the deviation is confined to 3–4 smoothing lengths, and is larger for low mass halos, it is likely due to numerical resolution effects.

  14. Pair production by a deep potential well

    International Nuclear Information System (INIS)

    Nikishov, A.I.

    1987-01-01

    Solutions are obtained for the Dirac and Klein-Gordon equations with a one-dimensional symmetric potential well, having a flat bottom and arbitrary depth, width and field strengths at the walls. Quasi-stationary solutions describing a pair production by the well and the inverse process are obtained. It is shown that if the pair production probability is small, it is expressed in terms of the pair production probability on one wall and the particle oscillation frequency in the well. If the well has a supercritical depth, the lower continuum contains positron resonance scattering states at energies close to the real part of the quasi-stationary level energy (Zeldovich's effect). The qualitative dependence of the positron penetration coefficient through the wall on its energy and the well depth is an evidence that the solution of the so called one-particle Dirac equation describes in fact a many-particle system with a charge of 0 or 1

  15. The effect of barite mud on the division of the detector energy window in density logging while drilling

    International Nuclear Information System (INIS)

    Zhang Li; Sun Jianmeng; Yu Huawei; Jiang Dong; Zhang Jing

    2012-01-01

    In the litho-density logging, formation density and lithology were acquired by calculating the total counts in certain energy window. Therefore, the division of the energy window directly affects the evaluation of density and lithology value. In the process of the energy window division, mud type affects the determination of the range of energy window. In this work, Monte Carlo simulation method was applied to study the range of energy window regarding to water mud and barite mud, respectively. The results show that the range of the energy window with barite mud is less than that of the water mud, and lithology identification will have greater' error in the barite mud. It is important to analyze influencing factors and improve the measurement accuracy of the litho-density logging. (authors)

  16. Experimental study of single-vertex $(e^{-}-e^{+})$ pair creation in a crystal

    CERN Multimedia

    2002-01-01

    This experiment will study the newly predicted process of $e^{-}-e^{+}$ pair production by high energy photons incident along major axial direction of a single crystal. This process is based upon the well-known channeling properties of negatively charged particles along atomic rows of a crystal. The $e^{-}-e^{+}$ pair creation may proceed in a one-step process, without violating energy and momentum conversation laws, due to the lowering of the total energy of the channeled electron (Fig. 1). \\\\ \\\\ The pair creation rate should increase with increasing photon energies (above a threshold of a few GeV) and largely exceed the Bethe-Heitler process rate for photon energies of a few tens of GeV. It is also expected that the created particles share the photon energy nearly equally, in contrast with the rather flat energy distribution associated with the Bethe-Heitler process. \\\\ \\\\ The experimental set-up (Fig. 2) is designed for the study of those two features: photon energy dependence of the pair creation rate, an...

  17. Multi-messenger constraints and pressure from dark matter annihilation into e--e+ pairs

    International Nuclear Information System (INIS)

    Wechakama, Maneenate

    2013-01-01

    Despite striking evidence for the existence of dark matter from astrophysical observations, dark matter has still escaped any direct or indirect detection until today. Therefore a proof for its existence and the revelation of its nature belongs to one of the most intriguing challenges of nowadays cosmology and particle physics. The present work tries to investigate the nature of dark matter through indirect signatures from dark matter annihilation into electron-positron pairs in two different ways, pressure from dark matter annihilation and multi-messenger constraints on the dark matter annihilation cross-section. We focus on dark matter annihilation into electron-positron pairs and adopt a model-independent approach, where all the electrons and positrons are injected with the same initial energy E 0 ∝m dm c 2 . The propagation of these particles is determined by solving the diffusion-loss equation, considering inverse Compton scattering, synchrotron radiation, Coulomb collisions, bremsstrahlung, and ionization. The first part of this work, focusing on pressure from dark matter annihilation, demonstrates that dark matter annihilation into electron-positron pairs may affect the observed rotation curve by a significant amount. The injection rate of this calculation is constrained by INTEGRAL, Fermi, and H.E.S.S. data. The pressure of the relativistic electron-positron gas is computed from the energy spectrum predicted by the diffusion-loss equation. For values of the gas density and magnetic field that are representative of the Milky Way, it is estimated that the pressure gradients are strong enough to balance gravity in the central parts if E 0 0 . By comparing the predicted rotation curves with observations of dwarf and low surface brightness galaxies, we show that the pressure from dark matter annihilation may improve the agreement between theory and observations in some cases, but it also imposes severe constraints on the model parameters (most notably, the

  18. Longitudinal spin dependence of massive lepton pair production

    International Nuclear Information System (INIS)

    Berger, E. L.; Gordon, L. E.; Klasen, M.

    2000-01-01

    In this paper, the authors summarize recent work in which they demonstrate that the Compton subprocess, q + g -> γ* + q also dominates the Drell-Yan cross section in polarized and unpolarized proton-proton reactions for values of the transverse momentum Q T of the pair that are larger than roughly half of the pair mass Q, Q T > Q/2. The Drell-Yan process is therefore a valuable, heretofore overlooked, independent source of constraints on the spin-averaged and spin-dependent gluon densities. Although the Drell-Yan cross section is smaller than the prompt photon cross section, massive lepton pair production is cleaner theoretically since long-range fragmentation contributions are absent as are the experimental and theoretical complications associated with isolation of the real photon. Moreover, the dynamics of spin-dependence in hard-scattering processes is a sufficiently complex topic, and its understanding at an early stage in its development, that several defensible approaches for extracting polarized parton densities deserve to be pursued with the expectation that consistent results must emerge

  19. Nonlinear electrostatic structures in homogeneous and inhomogeneous pair-ion plasmas

    International Nuclear Information System (INIS)

    Mahmood, S.; Ur-Rehman, H.; Shah, A.; Haque, Q.

    2012-01-01

    The nonlinear electrostatic structures such as solitons, shocks were studied in homogeneous, unmagnetized pair-ion plasma. The dissipation in the system was taken through kinematic viscosities of both pair-ion species. The one dimensional (Korteweg-de Vries-Burgers) KdVB equation was derived using reductive perturbation method. The analytical solution of KdVB equation was obtained using tanh method. It was found that solitons and monotonic shocks structures were formed in such type of plasmas depending on the value of dissipation in the system. Both compressive and refractive structures of solitons and monotonic shocks were obtained depending on the temperatures of negative and positive ions. The oscillatory shock structures in pair-ion plasmas were also obtained and its necessary conditions of formation were discussed. The acoustic solitons were also investigated in inhomogeneous unmagnetized pair-ion plasmas. The Korteweg-de Vries (KdV) like equation with an additional term due to density gradients was obtained by employing the reductive perturbation technique. It was found that amplitude of both compressive and refractive solitons was found to be enhanced as the density gradient parameter was increased. The Landau damping rates of electrostatic ion waves were studied for non-Maxwellian or Lorentzian pair-ion plasmas. The Val sov equation was solved analytically for weak damping effects in pair-ion plasma. It was found that Landau damping rate of ion plasma wave was increased in Lorentzian case in comparison with Maxwellian pair-ion plasmas. The numerical results were obtained by taking into account the parameters of pair-ion plasmas produced in laboratory experiments in Japan. (orig./A.B.)

  20. Effect of light energy density on conversion degree and hardness of dual-cured resin cement.

    Science.gov (United States)

    Komori, Paula Carolina de Paiva; de Paula, Andréia Bolzan; Martin, Airton Abrāo; Tango, Rubens Nisie; Sinhoreti, Mario Alexandre Coelho; Correr-Sobrinho, Lourenço

    2010-01-01

    This study evaluated the effect of different light energy densities on conversion degree (CD) and Knoop hardness number (KHN) of RelyX ARC (RLX) resin cement. After manipulation according to the manufacturer's instructions, RLX was inserted into a rubber mold (0.8 mm x 5 mm) and covered with a Mylar strip. The tip of the light-curing unit (LCU) was positioned in contact with the Mylar surface. Quartz-tungsten-halogen (QTH) and light-emitting diode (LED) LCUs with light densities of 10, 20 and 30 J/cm2 were used to light-cure the specimens. After light curing, the specimens were stored dry in lightproof containers at 37 degrees C. After 24 hours, the CD was analyzed by FT-Raman and, after an additional 24-hours, samples were submitted to Knoop hardness testing. The data of the CD (%) and KHN were submitted to two-way ANOVA and the Tukey's test (alpha = 0.05). QTH and LED were effective light curing units. For QTH, there were no differences among the light energy densities for CD or KHN. For LED, there was a significant reduction in CD with the light energy density set at 10 J/cm2. KHN was not influenced by the light-curing unit and by its light energy density.

  1. Measurements relating fire radiative energy density and surface fuel consumption - RxCADRE 2011 and 2012

    Science.gov (United States)

    Andrew T. Hudak; Matthew B. Dickinson; Benjamin C. Bright; Robert L. Kremens; E. Louise Loudermilk; Joseph J. O' Brien; Benjamin S. Hornsby; Roger D. Ottmar

    2016-01-01

    Small-scale experiments have demonstrated that fire radiative energy is linearly related to fuel combusted but such a relationship has not been shown at the landscape level of prescribed fires. This paper presents field and remotely sensed measures of pre-fire fuel loads, consumption, fire radiative energy density (FRED) and fire radiative power flux density (FRFD),...

  2. Kinetic and electron-electron energies for convex sums of ground state densities with degeneracies and fractional electron number

    Energy Technology Data Exchange (ETDEWEB)

    Levy, Mel, E-mail: ayers@mcmaster.ca, E-mail: mlevy@tulane.edu [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Department of Physics, North Carolina A and T State University, Greensboro, North Carolina 27411 (United States); Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States); Anderson, James S. M.; Zadeh, Farnaz Heidar; Ayers, Paul W., E-mail: ayers@mcmaster.ca, E-mail: mlevy@tulane.edu [Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario (Canada)

    2014-05-14

    Properties of exact density functionals provide useful constraints for the development of new approximate functionals. This paper focuses on convex sums of ground-level densities. It is observed that the electronic kinetic energy of a convex sum of degenerate ground-level densities is equal to the convex sum of the kinetic energies of the individual degenerate densities. (The same type of relationship holds also for the electron-electron repulsion energy.) This extends a known property of the Levy-Valone Ensemble Constrained-Search and the Lieb Legendre-Transform refomulations of the Hohenberg-Kohn functional to the individual components of the functional. Moreover, we observe that the kinetic and electron-repulsion results also apply to densities with fractional electron number (even if there are no degeneracies), and we close with an analogous point-wise property involving the external potential. Examples where different degenerate states have different kinetic energy and electron-nuclear attraction energy are given; consequently, individual components of the ground state electronic energy can change abruptly when the molecular geometry changes. These discontinuities are predicted to be ubiquitous at conical intersections, complicating the development of universally applicable density-functional approximations.

  3. Similarity and self-similarity in high energy density physics: application to laboratory astrophysics

    International Nuclear Information System (INIS)

    Falize, E.

    2008-10-01

    The spectacular recent development of powerful facilities allows the astrophysical community to explore, in laboratory, astrophysical phenomena where radiation and matter are strongly coupled. The titles of the nine chapters of the thesis are: from high energy density physics to laboratory astrophysics; Lie groups, invariance and self-similarity; scaling laws and similarity properties in High-Energy-Density physics; the Burgan-Feix-Munier transformation; dynamics of polytropic gases; stationary radiating shocks and the POLAR project; structure, dynamics and stability of optically thin fluids; from young star jets to laboratory jets; modelling and experiences for laboratory jets

  4. 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.

  5. Pseudorapidity density of charged particles p-Pb collisions at $\\sqrt{s_{NN}}$ = 5.02 TeV

    CERN Document Server

    Abelev, Betty; Adamova, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agocs, Andras Gabor; Agostinelli, Andrea; Ahammed, Zubayer; Ahmad, Nazeer; Ahmad, Arshad; Ahn, Sang Un; Ahn, Sul-Ah; Ajaz, Muhammad; Akindinov, Alexander; Aleksandrov, Dmitry; Alessandro, Bruno; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Almaraz Avina, Erick Jonathan; Alme, Johan; Alt, Torsten; Altini, Valerio; Altinpinar, Sedat; Altsybeev, Igor; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anson, Christopher Daniel; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshauser, Harald; Arbor, Nicolas; Arcelli, Silvia; Arend, Andreas; Armesto, Nestor; Arnaldi, Roberta; Aronsson, Tomas Robert; Arsene, Ionut Cristian; Arslandok, Mesut; Asryan, Andzhey; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Aysto, Juha Heikki; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; 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