Medium corrections to nucleon-nucleon interactions

International Nuclear Information System (INIS)

Dortmans, P.J.; Amos, K.

1990-01-01

The Bethe-Goldstone equations have been solved for both negative and positive energies to specify two nucleon G-matrices fully off of the energy shell. Medium correction effects of Pauli blocking and of the auxiliary potential are included in infinite matter systems characterized by fermi momenta in the range 0.5 fm -1 to 1.8 fm -1 . The Paris interaction is used as the starting potential in most calculations. Medium corrections are shown to be very significant over a large range of energies and densities. On the energy shell values of G-matrices vary markedly from those of free two nucleon (NN) t-matrices which have been solved by way of the Lippmann-Schwinger equation. Off of the energy shell, however, the free and medium corrected Kowalski-Noyes f-ratios rate are quite similar suggesting that a useful model of medium corrected G-matrices are appropriately scaled free NN t-matrices. The choice of auxiliary potential form is also shown to play a decisive role in the negative energy regime, especially when the saturation of nuclear matter is considered. 30 refs., 7 tabs., 7 figs

Shell effects in the nuclear deformation energy

International Nuclear Information System (INIS)

Ross, C.K.

1973-01-01

A new approach to shell effects in the Strutinsky method for calculating nuclear deformation energy is evaluated and the suggestion of non-conservation of angular momentum in the same method is resolved. Shell effects on the deformation energy in rotational bands of deformed nuclei are discussed. (B.F.G.)

Wireless energy transfer between anisotropic metamaterials shells

Energy Technology Data Exchange (ETDEWEB)

Díaz-Rubio, Ana; Carbonell, Jorge; Sánchez-Dehesa, José, E-mail: jsdehesa@upv.es

2014-06-15

The behavior of strongly coupled Radial Photonic Crystals shells is investigated as a potential alternative to transfer electromagnetic energy wirelessly. These sub-wavelength resonant microstructures, which are based on anisotropic metamaterials, can produce efficient coupling phenomena due to their high quality factor. A configuration of selected constitutive parameters (permittivity and permeability) is analyzed in terms of its resonant characteristics. The coupling to loss ratio between two coupled resonators is calculated as a function of distance, the maximum (in excess of 300) is obtained when the shells are separated by three times their radius. Under practical conditions an 83% of maximum power transfer has been also estimated. -- Highlights: •Anisotropic metamaterial shells exhibit high quality factors and sub-wavelength size. •Exchange of electromagnetic energy between shells with high efficiency is analyzed. •Strong coupling is supported with high wireless transfer efficiency. •End-to-end energy transfer efficiencies higher than 83% can be predicted.

Wireless energy transfer between anisotropic metamaterials shells

International Nuclear Information System (INIS)

Díaz-Rubio, Ana; Carbonell, Jorge; Sánchez-Dehesa, José

2014-01-01

The behavior of strongly coupled Radial Photonic Crystals shells is investigated as a potential alternative to transfer electromagnetic energy wirelessly. These sub-wavelength resonant microstructures, which are based on anisotropic metamaterials, can produce efficient coupling phenomena due to their high quality factor. A configuration of selected constitutive parameters (permittivity and permeability) is analyzed in terms of its resonant characteristics. The coupling to loss ratio between two coupled resonators is calculated as a function of distance, the maximum (in excess of 300) is obtained when the shells are separated by three times their radius. Under practical conditions an 83% of maximum power transfer has been also estimated. -- Highlights: •Anisotropic metamaterial shells exhibit high quality factors and sub-wavelength size. •Exchange of electromagnetic energy between shells with high efficiency is analyzed. •Strong coupling is supported with high wireless transfer efficiency. •End-to-end energy transfer efficiencies higher than 83% can be predicted

Shell stabilization of super- and hyperheavy nuclei without magic gaps

International Nuclear Information System (INIS)

Bender, M.; Nazarewicz, W.; Oak Ridge National Lab., TN; Warsaw Univ.; Reinhard, P.G.; Oak Ridge National Lab., TN

2001-05-01

Quantum stabilization of superheavy elements is quantified in terms of the shell-correction energy. We compute the shell correction using self-consistent nuclear models: the non-relativistic Skyrme-Hartree-Fock approach and the relativistic mean-field model, for a number of parametrizations. All the forces applied predict a broad valley of shell stabilization around Z = 120 and N = 172-184. We also predict two broad regions of shell stabilization in hyperheavy elements with N ∼ 258 and N ∼ 308. Due to the large single-particle level density, shell corrections in the superheavy elements differ markedly from those in lighter nuclei. With increasing proton and neutron numbers, the regions of nuclei stabilized by shell effects become poorly localized in particle number, and the familiar pattern of shells separated by magic gaps is basically gone. (orig.)

Contribution of inner shell Compton ionization to the X-ray fluorescence line intensity

Science.gov (United States)

Fernández, Jorge E.; Scot, Viviana; Di Giulio, Eugenio

2016-10-01

The Compton effect is a potential ionization mechanism of atoms. It produces vacancies in inner shells that are filled with the same mechanism of atomic relaxation as the one following photo-absorption. This contribution to X-ray fluorescence emission is frequently neglected because the total Compton cross-section is apparently much lower than the photoelectric one at useful X-ray energies. However, a more careful analysis suggests that is necessary to consider single shell cross sections (instead of total cross sections) as a function of energy. In this article these Compton cross sections are computed for the shells K, L1-L3 and M1-M5 in the framework of the impulse approximation. By comparing the Compton and the photoelectric cross-section for each shell it is then possible to determine the extent of the Compton correction to the intensity of the corresponding characteristic lines. It is shown that for the K shell the correction becomes relevant for excitation energies which are too high to be influent in X-ray spectrometry. In contrast, for L and M shells the Compton contribution is relevant for medium-Z elements and medium energies. To illustrate the different grades of relevance of the correction, for each ionized shell, the energies for which the Compton contribution reaches the extent levels of 1, 5, 10, 20, 50 and 100% of the photoelectric one are determined for all the elements with Z = 11-92. For practical applications it is provided a simple formula and fitting coefficients to compute average correction levels for the shells considered.

Quantum electrodynamic corrections for the valence shell in heavy many-electron atoms

International Nuclear Information System (INIS)

Thierfelder, C.; Schwerdtfeger, P.

2010-01-01

We present quantum electrodynamic (QED) calculations within the picture of bound-state QED for the frequency-dependent Breit interaction between electrons, the vacuum polarization, and the electron self-energy correction starting from the Dirac-Coulomb Hamiltonian for the ionization potentials of the group 1, 2, 11, 12, 13, and 18 elements of the periodic table, and down to the superheavy elements up to nuclear charge Z=120. The results for the s-block elements are in very good agreement with earlier studies by Labzowsky et al. [Phys. Rev. A 59, 2707 (1999)]. We discuss the influence of the variational versus perturbative treatment of the Breit interaction for valence-space ionization potentials. We argue that the lowest-order QED contributions become as important as the Breit interaction for ionization potentials out of the valence s shell.

A generic double-curvature piezoelectric shell energy harvester: Linear/nonlinear theory and applications

Science.gov (United States)

Zhang, X. F.; Hu, S. D.; Tzou, H. S.

2014-12-01

Converting vibration energy to useful electric energy has attracted much attention in recent years. Based on the electromechanical coupling of piezoelectricity, distributed piezoelectric zero-curvature type (e.g., beams and plates) energy harvesters have been proposed and evaluated. The objective of this study is to develop a generic linear and nonlinear piezoelectric shell energy harvesting theory based on a double-curvature shell. The generic piezoelectric shell energy harvester consists of an elastic double-curvature shell and piezoelectric patches laminated on its surface(s). With a current model in the closed-circuit condition, output voltages and energies across a resistive load are evaluated when the shell is subjected to harmonic excitations. Steady-state voltage and power outputs across the resistive load are calculated at resonance for each shell mode. The piezoelectric shell energy harvesting mechanism can be simplified to shell (e.g., cylindrical, conical, spherical, paraboloidal, etc.) and non-shell (beam, plate, ring, arch, etc.) distributed harvesters using two Lamé parameters and two curvature radii of the selected harvester geometry. To demonstrate the utility and simplification procedures, the generic linear/nonlinear shell energy harvester mechanism is simplified to three specific structures, i.e., a cantilever beam case, a circular ring case and a conical shell case. Results show the versatility of the generic linear/nonlinear shell energy harvesting mechanism and the validity of the simplification procedures.

Ground state energy fluctuations in the nuclear shell model

International Nuclear Information System (INIS)

Velazquez, Victor; Hirsch, Jorge G.; Frank, Alejandro; Barea, Jose; Zuker, Andres P.

2005-01-01

Statistical fluctuations of the nuclear ground state energies are estimated using shell model calculations in which particles in the valence shells interact through well-defined forces, and are coupled to an upper shell governed by random 2-body interactions. Induced ground-state energy fluctuations are found to be one order of magnitude smaller than those previously associated with chaotic components, in close agreement with independent perturbative estimates based on the spreading widths of excited states

Measurements of L-shell x-ray production cross-sections of Au and Ag by low energy electron impact

International Nuclear Information System (INIS)

Wu, Y; An, Z; Liu, M T; Duan, Y M; Tang, C H; Luo, Z M

2004-01-01

Au L α and L β and Ag L-shell x-ray production cross-sections by electron impact have been measured in the incident energy region from near threshold to about 25 keV. Thin films with thick aluminium substrates were used as targets in the experiments. The effect of directional and energy spreading of the electron beam within the active films and x-ray enhancement due to backscattering electrons and bremsstrahlung photons from the substrates are corrected by means of Monte Carlo simulations. The corrected experimental data provided by this method are compared with calculated cross-sections from a PWBA theory with Coulomb, relativistic and exchange corrections and with other experimental data available in the literature

Semiclassical moment of inertia shell-structure within the phase-space approach

International Nuclear Information System (INIS)

Gorpinchenko, D V; Magner, A G; Bartel, J; Blocki, J P

2015-01-01

The moment of inertia for nuclear collective rotations is derived within a semiclassical approach based on the cranking model and the Strutinsky shell-correction method by using the non-perturbative periodic-orbit theory in the phase-space variables. This moment of inertia for adiabatic (statistical-equilibrium) rotations can be approximated by the generalized rigid-body moment of inertia accounting for the shell corrections of the particle density. A semiclassical phase-space trace formula allows us to express the shell components of the moment of inertia quite accurately in terms of the free-energy shell corrections for integrable and partially chaotic Fermi systems, which is in good agreement with the corresponding quantum calculations. (paper)

Electron energy spectrum in core-shell elliptic quantum wire

Directory of Open Access Journals (Sweden)

V.Holovatsky

2007-01-01

Full Text Available The electron energy spectrum in core-shell elliptic quantum wire and elliptic semiconductor nanotubes are investigated within the effective mass approximation. The solution of Schrodinger equation based on the Mathieu functions is obtained in elliptic coordinates. The dependencies of the electron size quantization spectrum on the size and shape of the core-shell nanowire and nanotube are calculated. It is shown that the ellipticity of a quantum wire leads to break of degeneration of quasiparticle energy spectrum. The dependences of the energy of odd and even electron states on the ratio between semiaxes are of a nonmonotonous character. The anticrosing effects are observed at the dependencies of electron energy spectrum on the transversal size of the core-shell nanowire.

Semiclassical shell structure in rotating Fermi systems

International Nuclear Information System (INIS)

Magner, A. G.; Sitdikov, A. S.; Khamzin, A. A.; Bartel, J.

2010-01-01

The collective moment of inertia is derived analytically within the cranking model for any rotational frequency of the harmonic-oscillator potential well and at a finite temperature. Semiclassical shell-structure components of the collective moment of inertia are obtained for any potential by using the periodic-orbit theory. We found semiclassically their relation to the free-energy shell corrections through the shell-structure components of the rigid-body moment of inertia of the statistically equilibrium rotation in terms of short periodic orbits. The shell effects in the moment of inertia exponentially disappear with increasing temperature. For the case of the harmonic-oscillator potential, one observes a perfect agreement of the semiclassical and quantum shell-structure components of the free energy and the moment of inertia for several critical bifurcation deformations and several temperatures.

Zero-point energy of N perfectly conducting concentric cylindrical shells

International Nuclear Information System (INIS)

Tatur, K.; Woods, L.M.

2008-01-01

The zero-point (Casimir) energy of N perfectly conducting, infinitely long, concentric cylindrical shells is calculated utilizing the mode summation technique. The obtained convergent expression is studied as a function of size, curvature and number of shells. Limiting cases, such as infinitely close shells or infinite radius shells are also investigated

On-shell gauge-parameter independence of contributions to electroweak quark self-energies

International Nuclear Information System (INIS)

Ahmady, M.R.; Elias, V.; Mendel, R.R.; Scadron, M.D.; Steele, T.

1989-01-01

We allow an external condensate to enter standard SU(2) x U(1) electroweak theory via the vacuum expectation value , as in QCD sum-rule applications. For a given flavor, we then find that any gauge-parameter dependence of quark self-energies on the ''mass shell'' is eliminated provided that the mass shell is made to coincide with both the expansion-parameter mass occurring in the operator-product expansion of and the standard electroweak mass acquired via the Yukawa coupling to the usual scalar vacuum expectation value of spontaneous symmetry breaking. This result indicates that if the QCD-generated order parameter and associated dynamical mass(es) m/sub q//sup dyn/ are utilized as external input parameters in electroweak calculations involving hadrons, then new corrections must be introduced into the q-barqW and q-barqZ vertices in order to preserve SU(2) x U(1) Ward identities

Copper K-shell emission cross sections for laser–solid experiments

Energy Technology Data Exchange (ETDEWEB)

Davies, J. R.; Betti, R.; Nilson, P. M.; Solodov, A. A. [Fusion Science Center for Extreme States of Matter, Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

2013-08-15

Published measurements and models of the cross section for electrons causing K-shell emission from copper are reviewed to find a suitable expression to use when analyzing K{sub α}-emission measurements in laser–solid experiments at peak intensities above 10{sup 18} W/cm{sup 2}. Few measurements exist in the 0.1- to 10-MeV electron energy range currently of interest, leaving a number of possible suitable models that are summarized here with a number of typing errors corrected. Two different limiting forms for the cross section at relativistic energies are used, and existing measurements do not give a clear indication as to which is correct. Comparison with the limiting form of electron stopping power indicates an alternative relativistic form and also that the density-effect correction will be important in copper above 10 MeV. For data analysis relying on relative K{sub α} emission caused by electrons with energy much greater than the K-shell binding energy, the existing uncertainty in cross sections is unimportant, but it will be a source of uncertainty when using absolute values and for electron energies up to ∼6× the binding energy. K-shell emission caused by photons and protons is also briefly reviewed.

Some Comments on the Status of Shell Theory at the End of the 20th Century: Complaints and Correctives

Science.gov (United States)

Simmonds, James G.

1998-01-01

This review is divided into complaints and correctives. Complaints are directed at: sloppy refereeing and editing; authors who fail to read or acknowledge what others have done; the mis-naming or mis-crediting of results; the misunderstanding and misuse of the Kirchhoff hypothesis; inflated claims of accuracy based on overly-simplified benchmark problems; the failure to appreciate the inherent errors in various shell models; the failure to appreciate that the physical response and mathematical structure of shell theory are fundamentally different from 3-dimensional elasticity; and the irrelevance of Cosserat-type theories. Correctives include a simple, straight-forward derivation of a general nonlinear dynamic shell theory with the following features: (1) the equations of motion and kinematics (and those of thermodynamics, if desired) are exact consequences of their 3-dimensional counterparts; (2) there are no asymptotic or series expansions through the thickness; (3) all approximations (including the Kirchhoff Hypothesis) occur in the constitutive relations; (4) in static problems, there is a mixed form of the governing equations involving a mixed-energy density and exhibiting remnants of the well-known static-geometric duality of linear theory which is numerically robust because the limiting cases of nonlinear membrane theory and inextensional bending theory fall out naturally. (These latter two special cases are known to produce numerical nightmares unless treated with great care); and (5) all equations may be expressed in coordinate-free form (although, sometimes, a hybrid form is shown to be superior).

Shell effects at the touching point of nuclear fragments

International Nuclear Information System (INIS)

Poenaru, D.N.; Gherghescu, R.A.; Greiner, W.

1999-01-01

Shell correction energy of the fission fragments remains practically unchanged when the separation distance increases from the sum of their radii up to infinity. The variation with mass asymmetry of the total deformation energy at the touching point configuration shows the valleys corresponding to different decay modes, which are produced when the two proton and/or the two neutron numbers are magic or almost magic. We present a potential energy surface of the proton-rich α-emitter 106 Te, showing the α-decay valley, obtained with a phenomenological shell correction. We discuss the difficulties to produce such a valley on a potential energy surface of 236 Pu, calculated with the macroscopic-microscopic method, in which the nuclear level scheme is found within the two center shell model. The valleys mainly due to the double magic nuclei 100,132 Sn, 208 Pb, and other magic numbers, are illustrated by plotting the deformation energy at the touching point versus the proton number of the fragment, for the following parent nuclei: 106 Te, 116 Ce, 212 Po, 238 Th, 258 Fm and 264 Fm. For ternary fission the gain in energy of compact configurations as compared to aligned ones is analysed. (authors)

Energy from seed shells of Jatropha curcas; Energie aus Samenschalen von Jatropha curcas

Energy Technology Data Exchange (ETDEWEB)

Kratzeisen, Martin [Hohenheim Univ. (Germany). Inst. fuer Agrartechnik in den Tropen und Subtropen; Mueller, Joachim

2009-07-01

The seed shells of the oleiferous fruit Jatropha curcas is a promising fuel in tropical and subtropical countries. The thermal energy can be applied in many ways for example for drying Jatropha nuts or processing biodiesel from Jatropha oil. The calorific value of the shells is between 16-17 MJ/kg and thus similar to wood, which is a main energy source in developing countries until now. (orig.)

Shell Thickness Dependence of Interparticle Energy Transfer in Core-Shell ZnSe/ZnSe Quantum Dots Doping with Europium

Science.gov (United States)

Liu, Ni; Li, Shuxin; Wang, Caifeng; Li, Jie

2018-04-01

Low-toxic core-shell ZnSe:Eu/ZnS quantum dots (QDs) were prepared through two steps in water solution: nucleation doping and epitaxial shell grown. The structural and morphological characteristics of ZnSe/ZnS:Eu QDs with different shell thickness were explored by transmission electron microscopy (TEM) and X-ray diffraction (XRD) results. The characteristic photoluminescence (PL) intensity of Eu ions was enhanced whereas that of band-edge luminescence and defect-related luminescence of ZnSe QDs was decreased with increasing shell thickness. The transformation of PL intensity revealed an efficient energy transfer process between ZnSe and Eu. The PL intensity ratio of Eu ions ( I 613) to ZnSe QDs ( I B ) under different shell thickness was systemically analyzed by PL spectra and time-resolved PL spectra. The obtained results were in agreement with the theory analysis results by the kinetic theory of energy transfer, revealing that energy was transmitted in the form of dipole-electric dipole interaction. This particular method of adjusting luminous via changing the shell thickness can provide valuable insights towards the fundamental understanding and application of QDs in the field of optoelectronics.

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

Nondestructive pasteurization of shell eggs using radio frequency energy

Science.gov (United States)

Shell eggs are on the top of the list of the 10 riskiest foods regulated by the Food and Drug Administration and 352 outbreaks from 1990 to 2006 were linked to eggs. The goals of this study were to design and assemble an apparatus to apply RF energy to shell eggs and to develop a process for pasteur...

STUDY OF SHELL FOR ENERGY EFFICIENT OF SUSTAINABLE LOW-RISE BUILDING

Directory of Open Access Journals (Sweden)

DANISHEVSKYI V. V.

2016-03-01

Full Text Available The article presents the results of study the shell for energy-efficient environmental low-rise residential building, corresponding to the criteria of sustainable development in construction. Purpose. The purpose of the presented research is providing a study of parameters for shell of energy-efficient environmental low-rise buildings. Methodology. Research is carried out on the basis of an improved method for calculating the thermal characteristics of the external walling, as well as physical heat transfer simulation. Conclusion.The ratio between the thickness of external walling and the proportion of heat loss through them was determined, and also the heat loss through thermal "bridges" was studied. Originality. The limits for the optimum thickness of the external walling of ecological materials was analyzed, and it was offered solution for minimization of heat loss through the nodes of shell. Practical value.Recommendations are worked out on constructing of thermal shell at planning of energy-efficient low-rise residential buildings.

Region of validity of the Thomas–Fermi model with quantum, exchange and shell corrections

International Nuclear Information System (INIS)

Dyachkov, S A; Levashov, P R; Minakov, D V

2016-01-01

A novel approach to calculate thermodynamically consistent shell corrections in wide range of parameters is used to predict the region of validity of the Thomas-Fermi approach. Calculated thermodynamic functions of electrons at high density are consistent with the more precise density functional theory. It makes it possible to work out a semi-classical model applicable both at low and high density. (paper)

Local and global Casimir energies for a semitransparent cylindrical shell

International Nuclear Information System (INIS)

Cavero-Pelaez, Ines; Milton, Kimball A; Kirsten, Klaus

2007-01-01

The local Casimir energy density and the global Casimir energy for a massless scalar field associated with a λδ-function potential in a (3 + 1)-dimensional circular cylindrical geometry are considered. The global energy is examined for both weak and strong coupling, the latter being the well-studied Dirichlet cylinder case. For weak coupling, through O(λ 2 ), the total energy is shown to vanish by both analytic and numerical arguments, based both on Green's-function and zeta-function techniques. Divergences occurring in the calculation are shown to be absorbable by renormalization of physical parameters of the model. The global energy may be obtained by integrating the local energy density only when the latter is supplemented by an energy term residing precisely on the surface of the cylinder. The latter is identified as the integrated local energy density of the cylindrical shell when the latter is physically expanded to have finite thickness. Inside and outside the δ-function shell, the local energy density diverges as the surface of the shell is approached; the divergence is weakest when the conformal stress tensor is used to define the energy density. A real global divergence first occurs in O(λ 3 ), as anticipated, but the proof is supplied here for the first time; this divergence is entirely associated with the surface energy and does not reflect divergences in the local energy density as the surface is approached

Semiclassical shell structure of moments of inertia in deformed Fermi systems

International Nuclear Information System (INIS)

Magner, A.G.; Gzhebinsky, A.M.; Sitdikov, A.S.; Khamzin, A.A.; Bartel, J.

2010-01-01

The collective moment of inertia is derived analytically within the cranking model in the adiabatic mean-field approximation at finite temperature. Using the nonperturbative periodic-orbit theory the semiclassical shell-structure components of the collective moment of inertia are obtained for any potential well. Their relation to the free-energy shell corrections are found semiclassically as being given through the shell-structure components of the rigid-body moment of inertia of the statistically equilibrium rotation in terms of short periodic orbits. Shell effects in the moment of inertia disappear exponentially with increasing temperature. For the case of the harmonic-oscillator potential one observes a perfect agreement between semiclassical and quantum shell-structure components of the free energy and the moment of inertia for several critical bifurcation deformations and several temperatures. (author)

Active constrained layer damping treatments for shell structures: a deep-shell theory, some intuitive results, and an energy analysis

Science.gov (United States)

Shen, I. Y.

1997-02-01

This paper studies vibration control of a shell structure through use of an active constrained layer (ACL) damping treatment. A deep-shell theory that assumes arbitrary Lamé parameters 0964-1726/6/1/011/img1 and 0964-1726/6/1/011/img2 is first developed. Application of Hamilton's principle leads to the governing Love equations, the charge equation of electrostatics, and the associated boundary conditions. The Love equations and boundary conditions imply that the control action of the ACL for shell treatments consists of two components: free-end boundary actuation and membrane actuation. The free-end boundary actuation is identical to that of beam and plate ACL treatments, while the membrane actuation is unique to shell treatments as a result of the curvatures of the shells. In particular, the membrane actuation may reinforce or counteract the boundary actuation, depending on the location of the ACL treatment. Finally, an energy analysis is developed to determine the proper control law that guarantees the stability of ACL shell treatments. Moreover, the energy analysis results in a simple rule predicting whether or not the membrane actuation reinforces the boundary actuation.

Low-energy impact of adaptive cylindrical piezoelectric-composite shells

Energy Technology Data Exchange (ETDEWEB)

Saravanos, D.A. [University of Patras (United Kingdom). Dept. of Mechanical Engineering and Aeronautics; Christoforou, A.P. [Kuwait Univ. (Kuwait). Dept. of Mechanical Engineering

2002-04-01

A theoretical framework for analyzing low-energy impacts of laminated shells with active and sensory piezoelectric layers is presented, including impactor dynamics and contact law. The formulation encompasses a coupled piezoelectric shell theory mixing first order shear displacement assumptions and layerwise variation of electric potential. An exact in-plane Ritz solution for the impact of open cylindrical piezoelectric-composite shells is developed and solved numerically using an explicit time integration scheme. The active impact control problem of adaptive cylindrical shells with distributed curved piezoelectric actuators is addressed. The cases of optimized state feedback controllers and output feedback controllers using piezoelectric sensors are analyzed. Numerical results quantify the impact response of cylindrical shells of various curvatures including the signal of curved piezoelectric sensors. Additional numerical studies quantify the impact response of adaptive cylindrical panels and investigate the feasibility of actively reducing the impact force. (author)

Core excitations across the neutron shell gap in 207Tl

Directory of Open Access Journals (Sweden)

E. Wilson

2015-07-01

Full Text Available The single closed-neutron-shell, one proton–hole nucleus 207Tl was populated in deep-inelastic collisions of a 208Pb beam with a 208Pb target. The yrast and near-yrast level scheme has been established up to high excitation energy, comprising an octupole phonon state and a large number of core excited states. Based on shell-model calculations, all observed single core excitations were established to arise from the breaking of the N=126 neutron core. While the shell-model calculations correctly predict the ordering of these states, their energies are compressed at high spins. It is concluded that this compression is an intrinsic feature of shell-model calculations using two-body matrix elements developed for the description of two-body states, and that multiple core excitations need to be considered in order to accurately calculate the energy spacings of the predominantly three-quasiparticle states.

Energy generation in convective shells of low mass, low metallicity stars

International Nuclear Information System (INIS)

Bazan, G.

1989-01-01

We report on the non-negligible energy generation from the 13 C neutron source and neutron capture reactions in low mass, low metallicity AGB stars. About 10 4 L circle-dot are generated within the thermal pulse convective shell by the combination of the 13 C(α, n) 16 O rate and the sum of the Y(Z,A)(n,γ)Y(Z,A + 1) reactions and beta decays. The inclusion of this energy source in an AGB thermal pulse evolution is shown to alter the evolution of the convective shell boundaries, and, hence, how the 13 C is ingested into the convective shell. Also, the duration of the pulse itself is reduced by the additional energy input. The nucleosynthetic consequences are discussed for these evolutionary changes. 17 refs., 5 figs

Nuclear mass formula with the shell energies obtained by a new method

International Nuclear Information System (INIS)

Koura, H.; Tachibana, T.; Yamada, M.; Uno, M.

1998-01-01

Nuclear shapes and masses are estimated by a new method. The main feature of this method lies in estimating shell energies of deformed nuclei from spherical shell energies by mixing them with appropriate weights. The spherical shell energies are calculated from single-particle potentials, and, till now, two mass formulas have been constructed from two different sets of potential parameters. The standard deviation of the calculated masses from all the experimental masses of the 1995 Mass Evaluation is about 760 keV. Contrary to the mass formula by Tachibana, Uno, Yamada and Yamada in the 1987-1988 Atomic Mass Predictions, the present formulas can give nuclear shapes and predict on super-heavy elements

NIF Double Shell outer/inner shell collision experiments

Science.gov (United States)

Merritt, E. C.; Loomis, E. N.; Wilson, D. C.; Cardenas, T.; Montgomery, D. S.; Daughton, W. S.; Dodd, E. S.; Desjardins, T.; Renner, D. B.; Palaniyappan, S.; Batha, S. H.; Khan, S. F.; Smalyuk, V.; Ping, Y.; Amendt, P.; Schoff, M.; Hoppe, M.

2017-10-01

Double shell capsules are a potential low convergence path to substantial alpha-heating and ignition on NIF, since they are predicted to ignite and burn at relatively low temperatures via volume ignition. Current LANL NIF double shell designs consist of a low-Z ablator, low-density foam cushion, and high-Z inner shell with liquid DT fill. Central to the Double Shell concept is kinetic energy transfer from the outer to inner shell via collision. The collision determines maximum energy available for compression and implosion shape of the fuel. We present results of a NIF shape-transfer study: two experiments comparing shape and trajectory of the outer and inner shells at post-collision times. An outer-shell-only target shot measured the no-impact shell conditions, while an `imaging' double shell shot measured shell conditions with impact. The `imaging' target uses a low-Z inner shell and is designed to perform in similar collision physics space to a high-Z double shell but can be radiographed at 16keV, near the viable 2DConA BL energy limit. Work conducted under the auspices of the U.S. DOE by LANL under contract DE-AC52-06NA25396.

Entropy-Corrected Holographic Dark Energy

International Nuclear Information System (INIS)

Wei Hao

2009-01-01

The holographic dark energy (HDE) is now an interesting candidate of dark energy, which has been studied extensively in the literature. In the derivation of HDE, the black hole entropy plays an important role. In fact, the entropy-area relation can be modified due to loop quantum gravity or other reasons. With the modified entropy-area relation, we propose the so-called 'entropy-corrected holographic dark energy' (ECHDE) in the present work. We consider many aspects of ECHDE and find some interesting results. In addition, we briefly consider the so-called 'entropy-corrected agegraphic dark energy' (ECADE). (geophysics, astronomy, and astrophysics)

Surface energy effect on free vibration of nano-sized piezoelectric double-shell structures

Science.gov (United States)

Fang, Xue-Qian; Zhu, Chang-Song; Liu, Jin-Xi; Liu, Xiang-Lin

2018-01-01

Combining Goldenveizer-Novozhilov shell theory, thin plate theory and electro-elastic surface theory, the size-dependent vibration of nano-sized piezoelectric double-shell structures under simply supported boundary condition is presented, and the surface energy effect on the natural frequencies is discussed. The displacement components of the cylindrical nano-shells and annular nano-plates are expanded as the superposition of standard Fourier series based on Hamilton's principle. The total stresses with consideration of surface energy effect are derived, and the total energy function is obtained by using Rayleigh-Ritz energy method. The free vibration equation is solved, and the natural frequency is analyzed. In numerical examples, it is found that the surface elastic constant, piezoelectric constant and surface residual stress show different effects on the natural frequencies. The effect of surface piezoelectric constant is the maximum. The effect of dimensions of the double-shell under different surface material properties is also examined.

Tuning upconversion through energy migration in core-shell nanoparticles

KAUST Repository

Wang, Feng; Deng, Renren; Wang, Juan; Wang, Qingxiao; Han, Yu; Zhu, Haomiao; Chen, Xueyuan; Liu, Xiaogang

2011-01-01

Photon upconversion is promising for applications such as biological imaging, data storage or solar cells. Here, we have investigated upconversion processes in a broad range of gadolinium-based nanoparticles of varying composition. We show that by rational design of a core-shell structure with a set of lanthanide ions incorporated into separated layers at precisely defined concentrations, efficient upconversion emission can be realized through gadolinium sublattice-mediated energy migration for a wide range of lanthanide activators without long-lived intermediary energy states. Furthermore, the use of the core-shell structure allows the elimination of deleterious cross-relaxation. This effect enables fine-tuning of upconversion emission through trapping of the migrating energy by the activators. Indeed, the findings described here suggest a general approach to constructing a new class of luminescent materials with tunable upconversion emissions by controlled manipulation of energy transfer within a nanoscopic region. © 2011 Macmillan Publishers Limited. All rights reserved.

Tuning upconversion through energy migration in core-shell nanoparticles

KAUST Repository

Wang, Feng

2011-10-23

Photon upconversion is promising for applications such as biological imaging, data storage or solar cells. Here, we have investigated upconversion processes in a broad range of gadolinium-based nanoparticles of varying composition. We show that by rational design of a core-shell structure with a set of lanthanide ions incorporated into separated layers at precisely defined concentrations, efficient upconversion emission can be realized through gadolinium sublattice-mediated energy migration for a wide range of lanthanide activators without long-lived intermediary energy states. Furthermore, the use of the core-shell structure allows the elimination of deleterious cross-relaxation. This effect enables fine-tuning of upconversion emission through trapping of the migrating energy by the activators. Indeed, the findings described here suggest a general approach to constructing a new class of luminescent materials with tunable upconversion emissions by controlled manipulation of energy transfer within a nanoscopic region. © 2011 Macmillan Publishers Limited. All rights reserved.

78 FR 14779 - Application to Export Electric Energy; Shell Energy North America (US), L.P.

Science.gov (United States)

2013-03-07

... DEPARTMENT OF ENERGY [OE Docket No. EA-339-A] Application to Export Electric Energy; Shell Energy... its authority to transmit electric energy from the United States to Canada pursuant to section 202(e... transmit electric energy from the United States to Canada as a power marketer for a five-year term using...

78 FR 14778 - Application to Export Electric Energy; Shell Energy North America (US), L.P.

Science.gov (United States)

2013-03-07

... DEPARTMENT OF ENERGY [OE Docket No. EA-338-A] Application to Export Electric Energy; Shell Energy... its authority to transmit electric energy from the United States to Mexico pursuant to section 202(e... transmit electric energy from the United States to Mexico as a power marketer for a five-year term using...

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.

Hylleraas-like functions with the correct cusp conditions: K-shell electrons for the neutral atoms

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, K.V. [Universidad Nacional del Sur, 8000 Bahia Blanca and Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina)], E-mail: krodri@criba.edu.ar; Gasaneo, G. [Universidad Nacional del Sur, 8000 Bahia Blanca and Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Mitnik, D.M.; Miraglia, J.E. [Instituto de Astronomia y Fisica del Espacio and Universidad de Buenos Aires (Argentina)

2007-10-15

We present simple correlated wavefunctions for the two K-shell electrons of neutral atoms. A variational method was chosen to calculate the mean energy of the ground state, in which the electrons are subject to a local Hartree potential representing the presence of the outer shell electrons. The functions are constructed in terms of exponential and power series, where special care has been taken in order to fulfill the exact behavior at the electron-electron and electron-nucleus coalescence points (Kato cusp conditions). Global properties, such as the energies and virial coefficients, as well as local properties, such as spatial mean values, are also analyzed.

Next-to-leading order electroweak corrections to off-shell WWW production at the LHC arXiv

CERN Document Server

Schönherr, Marek

Triboson processes allow for a measurement of the triple and quartic couplings of the Standard Model gauge bosons, which can be used to constrain anomalous gauge couplings. In this paper we calculate the next-to-leading order electroweak corrections to fully off-shell $W^-W^+W^+$ production, namely the production of a $\\ell_1^-\\ell_2^+\\ell_3^+\\bar{\

Coupled-states calculations of argon L-shell impact ionisation

International Nuclear Information System (INIS)

Martir, M.H.; Ford, A.L.; Reading, J.F.

1982-01-01

A coupled-states method is used to calculate the corrections to the first Born approximation for L-shell impact ionisation in the ion-atom collisions p+Ar and α+Ar at energies between 100 and 850 keV amu -1 . Using a classical projectile path and a pseudostate description of the ionisation continuum, the pseudostate and partial-wave convergence is considered. It is found that the absolute cross sections for these collisions are sensitive to the particular independent-particle-model (IPM) target-atom potential which is used. A modification to the long-range part of the neutral-atom Hartree-Fock (HF) potential is proposed that lowers the energy of the unbound pseudostates and that thereby brings the L-shell removal energies closer to the experimental ionisation potentials. With this modified HF potential good agreement between the present L-shell ionisation cross sections and experimental L-vacancy production cross sections is found. (author)

Effect of temperature on energy potential of pyrolysis products from oil palm shells

Directory of Open Access Journals (Sweden)

Lina María Romero Millán

2016-06-01

Full Text Available Context: Taking into account that near 220 000 tons of oil palm shells are produced every year in Colombia, as a waste of the Elaeis Guineensis palm oil transformation process, the aim of this work is to determine the energy potential of oil palm shells, when transformed through slow pyrolysis process. Methods: Using a fixed bed lab scale reactor, different oil palm shells pyrolysis tests were performed between 300°C and 500°C. The effect of the temperature in the process product yield and in the energy content of produced solids and gases were analyzed. Results: With a maximum mass yield of 50%, the char is considered the main product of oil palm shells pyrolysis, containing up to 73% of the raw biomass energy. The heating value of char raised with the temperature, from 29,6 MJ/kg at 300°C to 31,34 MJ/kg at 500°C. Moreover, the gas produced in the established temperature range had up to 13% of the energy content of the raw biomass, with a heating value near 12,5 MJ/m3. Conclusions: According to the results, slow pyrolysis can be considered an interesting process for the valorization of residual biomass as oil palm shells, through the production of solids and gases that can be used as fuels, or as precursor of other value-added products.

Prediction of mass excess, β-decay energy and neutron separation energy from the atomic mass formula with empirical shell terms

International Nuclear Information System (INIS)

Ando, Yoshihira; Uno, Masahiro; Yamada, Masami

1983-02-01

Recently we proposed two types of atomic mass formula (constant-shell-term formula, linear-shell-term formula). With use of these formulas, we calculate and tabulate mass excesses, neutron separation energies, and β-decay energies (β-decay and/or electron capture) for about 5000 nuclides. The mass excess values and their errors in the 1977 atomic mass evaluation by A.H. Wapstra and K. Bos which we used in constructing our formulas, are also tabulated for reference. The constant-shell-term formula is fitted to 1468 input mass data with the standard deviation of 626 keV and the linear-shell-term formula with 394 keV

Prediction of mass excess, #betta#-decay energy and neutron separation energy from the atomic mass formula with empirical shell terms

International Nuclear Information System (INIS)

Ando, Yoshihira; Uno, Masahiro; Yamada, Masami.

1983-02-01

Recently we proposed two types of atomic mass formula (constant-shell-term formula, linear-shell-term formula). With use of these formulas, we calculate and tabulate mass excesses, neutron separation energies, and #betta#-decay energies (#betta# - -decay and/or electron capture) for about 5000 nuclides. The mass excess values and their errors in the 1977 atomic mass evaluation by A.H. Wapstra and K. Bos which we used in constructing our formulas, are also tabulated for reference. The constant-shell-term formula is fitted to 1468 input mass data with the standard deviation of 626 keV and the linear-shell-term formula with 394 keV. (author)

Zero-point energy effects in anion solvation shells.

Science.gov (United States)

Habershon, Scott

2014-05-21

By comparing classical and quantum-mechanical (path-integral-based) molecular simulations of solvated halide anions X(-) [X = F, Cl, Br and I], we identify an ion-specific quantum contribution to anion-water hydrogen-bond dynamics; this effect has not been identified in previous simulation studies. For anions such as fluoride, which strongly bind water molecules in the first solvation shell, quantum simulations exhibit hydrogen-bond dynamics nearly 40% faster than the corresponding classical results, whereas those anions which form a weakly bound solvation shell, such as iodide, exhibit a quantum effect of around 10%. This observation can be rationalized by considering the different zero-point energy (ZPE) of the water vibrational modes in the first solvation shell; for strongly binding anions, the ZPE of bound water molecules is larger, giving rise to faster dynamics in quantum simulations. These results are consistent with experimental investigations of anion-bound water vibrational and reorientational motion.

Phase 1 RCRA Facility Investigation/Corrective Measures Study Work Plan for Single-Shell Tank (SST) Waste Management Areas

International Nuclear Information System (INIS)

MCCARTHY, M.M.

1999-01-01

This document is the master work plan for the Resource Conservation and Recovery Act of 1976 (RCRA) Corrective Action Program (RCAP) for single-shell tank (SST) farms at the US. Department of Energy's (DOE'S) Hanford Site. The DOE Office of River Protection (ORP) initiated the RCAP to address the impacts of past and potential future tank waste releases to the environment. This work plan defines RCAP activities for the four SST waste management areas (WMAs) at which releases have contaminated groundwater. Recognizing the potential need for future RCAP activities beyond those specified in this master work plan, DOE has designated the currently planned activities as ''Phase 1.'' If a second phase of activities is needed for the WMAs addressed in Phase 1, or if releases are detected at other SST WMAs, this master work plan will be updated accordingly

Singlet-paired coupled cluster theory for open shells

Science.gov (United States)

Gomez, John A.; Henderson, Thomas M.; Scuseria, Gustavo E.

2016-06-01

Restricted single-reference coupled cluster theory truncated to single and double excitations accurately describes weakly correlated systems, but often breaks down in the presence of static or strong correlation. Good coupled cluster energies in the presence of degeneracies can be obtained by using a symmetry-broken reference, such as unrestricted Hartree-Fock, but at the cost of good quantum numbers. A large body of work has shown that modifying the coupled cluster ansatz allows for the treatment of strong correlation within a single-reference, symmetry-adapted framework. The recently introduced singlet-paired coupled cluster doubles (CCD0) method is one such model, which recovers correct behavior for strong correlation without requiring symmetry breaking in the reference. Here, we extend singlet-paired coupled cluster for application to open shells via restricted open-shell singlet-paired coupled cluster singles and doubles (ROCCSD0). The ROCCSD0 approach retains the benefits of standard coupled cluster theory and recovers correct behavior for strongly correlated, open-shell systems using a spin-preserving ROHF reference.

Singlet-paired coupled cluster theory for open shells

International Nuclear Information System (INIS)

Gomez, John A.; Henderson, Thomas M.; Scuseria, Gustavo E.

2016-01-01

Restricted single-reference coupled cluster theory truncated to single and double excitations accurately describes weakly correlated systems, but often breaks down in the presence of static or strong correlation. Good coupled cluster energies in the presence of degeneracies can be obtained by using a symmetry-broken reference, such as unrestricted Hartree-Fock, but at the cost of good quantum numbers. A large body of work has shown that modifying the coupled cluster ansatz allows for the treatment of strong correlation within a single-reference, symmetry-adapted framework. The recently introduced singlet-paired coupled cluster doubles (CCD0) method is one such model, which recovers correct behavior for strong correlation without requiring symmetry breaking in the reference. Here, we extend singlet-paired coupled cluster for application to open shells via restricted open-shell singlet-paired coupled cluster singles and doubles (ROCCSD0). The ROCCSD0 approach retains the benefits of standard coupled cluster theory and recovers correct behavior for strongly correlated, open-shell systems using a spin-preserving ROHF reference.

L-shell x-ray yields and production cross-sections of molybdenum induced by low-energy highly charged argon ions

International Nuclear Information System (INIS)

Du Juan; Xu Jinzhang; Chen Ximeng; Yang Zhihu; Shao Jianxiong; Cui Ying; Zhang Hongqiang; Gao Zhimin; Liu Yuwen

2007-01-01

L-shell x-ray yields of molybdenum bombarded by highly charged Ar q+ ions (q=11-16) are measured. The x-ray production cross-sections are extracted from the yields data. The energy of the incident Ar ions ranges from 200 to 350 keV. After the binding energy correction, experimental data are explained in the framework of binary-encounter-approximation (BEA). The direct ionization is treated in the united atom (UA) limit (Lapicki and Lichten 1985 Phys. Rev. A 31 1354), not in the separate atom (SA) limit. The calculation results of BEA (Gacia and Fortner 1973 Rev. Mod. Phys. 45 111) are much lower than the experimental results, while the results of binding energy modified BEA are basically in agreement with the experimental results

Energy storage in ferroelectric polymer nanocomposites filled with core-shell structured polymer@BaTiO3 nanoparticles: understanding the role of polymer shells in the interfacial regions.

Science.gov (United States)

Zhu, Ming; Huang, Xingyi; Yang, Ke; Zhai, Xing; Zhang, Jun; He, Jinliang; Jiang, Pingkai

2014-11-26

The interfacial region plays a critical role in determining the electrical properties and energy storage density of dielectric polymer nanocomposites. However, we still know a little about the effects of electrical properties of the interfacial regions on the electrical properties and energy storage of dielectric polymer nanocomposites. In this work, three types of core-shell structured polymer@BaTiO3 nanoparticles with polymer shells having different electrical properties were used as fillers to prepare ferroelectric polymer nanocomposites. All the polymer@BaTiO3 nanoparticles were prepared by surface-initiated reversible-addition-fragmentation chain transfer (RAFT) polymerization, and the polymer shells were controlled to have the same thickness. The morphology, crystal structure, frequency-dependent dielectric properties, breakdown strength, leakage currents, energy storage capability, and energy storage efficiency of the polymer nanocomposites were investigated. On the other hand, the pure polymers having the same molecular structure as the shells of polymer@BaTiO3 nanoparticles were also prepared by RAFT polymerization, and their electrical properties were provided. Our results show that, to achieve nanocomposites with high discharged energy density, the core-shell nanoparticle filler should simultaneously have high dielectric constant and low electrical conductivity. On the other hand, the breakdown strength of the polymer@BaTiO3-based nanocomposites is highly affected by the electrical properties of the polymer shells. It is believed that the electrical conductivity of the polymer shells should be as low as possible to achieve nanocomposites with high breakdown strength.

Photoionization cross section and binding energy of single dopant in hollow cylindrical core/shell quantum dot

Science.gov (United States)

Feddi, E.; El-Yadri, M.; Dujardin, F.; Restrepo, R. L.; Duque, C. A.

2017-02-01

In this study, we have investigated the confined donor impurity in a hollow cylindrical-shell quantum dot. The charges are assumed to be completely confined to the interior of the shell with rigid walls. Within the framework of the effective-mass approximation and by using a simple variational approach, we have computed the donor binding energy as a function of the shell sizes in order to study the behavior of the electron-impurity attraction for a very small thickness. Our results show that the binding energy of a donor impurity placed at the center of cylindrical core/shell dots depends strongly on the shell size. The binding energy increases when the shell-wideness becomes smaller and shows the same behavior as in a simple cylindrical quantum dot. A special case has been studied, which corresponds to the ratio between the inner and outer radii near to one (a/b → 1) for which our model gives a non-significant behavior of the impurity binding energy. This fact implies the existence of a critical value (a/b) for which the binding energy of the donor impurity tends to the limit value of 4 effective Rydbergs as in a 2D quantum well. We also analyse the photoionization cross section considering only the in-plane incident radiation polarization. We determine its behavior as a function of photon energy, shell size, and donor position. The measurement of photoionization in such systems would be of great interest to understand the optical properties of carriers in quantum dots.

Compression Characteristics and Energy Requirement of Briquettes Made from a Mixture of Corn Stover and Peanut Shells

Directory of Open Access Journals (Sweden)

Chunxiao Gong

2015-07-01

Full Text Available Corn stover and peanut shells are both abundantly available biomass feedstocks in China. To determine the compression characteristics and energy requirement of briquettes, mixtures of the corn stover and peanut shells were compressed under three different pressures (30, 60, and 90 MPa with three moisture contents (9%, 14%, and 19%, wet basis and five corn stover-peanut shell mixtures (0%-100%, 25%-75%, 50%-50%, 75%-25%, and 100%-0% by mass. The results showed that applied pressure, moisture content, and the corn stover-peanut shell mixture all significantly affected briquette density and specific energy consumption. The density of the briquette ranged from 646 to 1052 kg/m3 and the specific energy consumption varied from 6.6 to 25.1 MJ/t. A moisture content of 9% was found to be better for the compression of the corn stover and peanut shells mixture. Adding peanut shells to the corn stover improved briquette density and reduced the specific energy consumption. Linear models were developed to describe the briquette density and the specific energy consumption. The briquette durability ranged from 57% to 94% and durable briquettes can be obtained when corn stover and peanut shells are compressed with the mixing ratio of 1:1 (50%-50% at moisture content of 9%.

Binding energies of sd-shell nuclei with a realistic effective Hamiltonian

International Nuclear Information System (INIS)

Dalton, B.J.; Vary, J.P.; Baldridge, W.J.

1977-01-01

The nuclear shell model with a second-order effective Hamiltonian derived within Brueckner theory from the free nucleon-nucleon interaction is shown to yield accurate binding energies of nuclei with 16 < A < 40. This agreement is obtained by choosing the spectrum of low-lying unoccupied orbitals in a justified manner and, when necessary, by employing a statistical method to approximate the lowest eigenvalue of very large shell-model diagonalizations

Shell-Tunneling Spectroscopy of the Single-Particle Energy Levels of Insulating Quantum Dots

NARCIS (Netherlands)

Bakkers, E.P.A.M.; Hens, Z.; Zunger, A.; Franceschetti, A; Kouwenhoven, L.P.; Gurevich, L.; Vanmaekelbergh, D.

2001-01-01

The energy levels of CdSe quantum dots are studied by scanning tunneling spectroscopy. By varying the tip-dot distance, we switch from "shell-filling" spectroscopy (where electrons accumulate in the dot and experience mutual repulsion) to "shell-tunneling" spectroscopy (where electrons tunnel, one

LRSPC, Proton High-Energy Loss in Matter

International Nuclear Information System (INIS)

2001-01-01

1 - Description of program or function: The LRSPC program is designed to estimate the energy loss, due to ionization and excitation, and the range of charged particles passing through matter. The code treats protons in elements or mixtures composed of elements with atomic numbers ranging from 1 to 100. The results for protons are generally valid from 1 MeV to 100 GeV. The code may be extended to treat other charged particles such as muons, pions, hyperons, deuterons, tritons and alphas by changing the particle mass, charge and range at 2 MeV. 2 - Method of solution: Stopping power is calculated from the Bethe-Bloch equation with shell and density corrections included. Range is calculated by integrating the reciprocal of the stopping power from an initial value at 2 MeV. The K-shell correction is taken from Walske's data. The L-shell and higher shell corrections are adjusted to fit low energy measurements fro 30 elements. The density correction is calculated by a method similar to that of Sternheimer, differing chiefly in the large number of electron shells considered. LRSPC computes improved proton range and stopping power data for use in the proton penetration code, LPPC (CCC-0051). It is packages separately and may be requested independently. 3 - Restrictions on the complexity of the problem: Number of elements in mixture ≤ 10, Atomic number of element ≤ 100, Number of energy points ≤ 500

Phase 1 RCRA Facility Investigation & Corrective Measures Study Work Plan for Single Shell Tank (SST) Waste Management Areas

Energy Technology Data Exchange (ETDEWEB)

MCCARTHY, M.M.

1999-08-01

This document is the master work plan for the Resource Conservation and Recovery Act of 1976 (RCRA) Corrective Action Program (RCAP) for single-shell tank (SST) farms at the US. Department of Energy's (DOE'S) Hanford Site. The DOE Office of River Protection (ORP) initiated the RCAP to address the impacts of past and potential future tank waste releases to the environment. This work plan defines RCAP activities for the four SST waste management areas (WMAs) at which releases have contaminated groundwater. Recognizing the potential need for future RCAP activities beyond those specified in this master work plan, DOE has designated the currently planned activities as ''Phase 1.'' If a second phase of activities is needed for the WMAs addressed in Phase 1, or if releases are detected at other SST WMAs, this master work plan will be updated accordingly.

An Energy Decaying Scheme for Nonlinear Dynamics of Shells

Science.gov (United States)

Bottasso, Carlo L.; Bauchau, Olivier A.; Choi, Jou-Young; Bushnell, Dennis M. (Technical Monitor)

2000-01-01

A novel integration scheme for nonlinear dynamics of geometrically exact shells is developed based on the inextensible director assumption. The new algorithm is designed so as to imply the strict decay of the system total mechanical energy at each time step, and consequently unconditional stability is achieved in the nonlinear regime. Furthermore, the scheme features tunable high frequency numerical damping and it is therefore stiffly accurate. The method is tested for a finite element spatial formulation of shells based on mixed interpolations of strain tensorial components and on a two-parameter representation of director rotations. The robustness of the, scheme is illustrated with the help of numerical examples.

A novel 3D absorption correction method for quantitative EDX-STEM tomography

International Nuclear Information System (INIS)

Burdet, Pierre; Saghi, Z.; Filippin, A.N.; Borrás, A.; Midgley, P.A.

2016-01-01

This paper presents a novel 3D method to correct for absorption in energy dispersive X-ray (EDX) microanalysis of heterogeneous samples of unknown structure and composition. By using STEM-based tomography coupled with EDX, an initial 3D reconstruction is used to extract the location of generated X-rays as well as the X-ray path through the sample to the surface. The absorption correction needed to retrieve the generated X-ray intensity is then calculated voxel-by-voxel estimating the different compositions encountered by the X-ray. The method is applied to a core/shell nanowire containing carbon and oxygen, two elements generating highly absorbed low energy X-rays. Absorption is shown to cause major reconstruction artefacts, in the form of an incomplete recovery of the oxide and an erroneous presence of carbon in the shell. By applying the correction method, these artefacts are greatly reduced. The accuracy of the method is assessed using reference X-ray lines with low absorption. - Highlights: • A novel 3D absorption correction method is proposed for 3D EDX-STEM tomography. • The absorption of X-rays along the path to the surface is calculated voxel-by-voxel. • The method is applied on highly absorbed X-rays emitted from a core/shell nanowire. • Absorption is shown to cause major artefacts in the reconstruction. • Using the absorption correction method, the reconstruction artefacts are greatly reduced.

A novel 3D absorption correction method for quantitative EDX-STEM tomography

Energy Technology Data Exchange (ETDEWEB)

Burdet, Pierre, E-mail: pierre.burdet@a3.epfl.ch [Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge CB3 0FS, Cambridgeshire (United Kingdom); Saghi, Z. [Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge CB3 0FS, Cambridgeshire (United Kingdom); Filippin, A.N.; Borrás, A. [Nanotechnology on Surfaces Laboratory, Materials Science Institute of Seville (ICMS), CSIC-University of Seville, C/ Americo Vespucio 49, 41092 Seville (Spain); Midgley, P.A. [Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge CB3 0FS, Cambridgeshire (United Kingdom)

2016-01-15

This paper presents a novel 3D method to correct for absorption in energy dispersive X-ray (EDX) microanalysis of heterogeneous samples of unknown structure and composition. By using STEM-based tomography coupled with EDX, an initial 3D reconstruction is used to extract the location of generated X-rays as well as the X-ray path through the sample to the surface. The absorption correction needed to retrieve the generated X-ray intensity is then calculated voxel-by-voxel estimating the different compositions encountered by the X-ray. The method is applied to a core/shell nanowire containing carbon and oxygen, two elements generating highly absorbed low energy X-rays. Absorption is shown to cause major reconstruction artefacts, in the form of an incomplete recovery of the oxide and an erroneous presence of carbon in the shell. By applying the correction method, these artefacts are greatly reduced. The accuracy of the method is assessed using reference X-ray lines with low absorption. - Highlights: • A novel 3D absorption correction method is proposed for 3D EDX-STEM tomography. • The absorption of X-rays along the path to the surface is calculated voxel-by-voxel. • The method is applied on highly absorbed X-rays emitted from a core/shell nanowire. • Absorption is shown to cause major artefacts in the reconstruction. • Using the absorption correction method, the reconstruction artefacts are greatly reduced.

Solar energy: Shell buys up the shares of Siemens and E.ON in their joint-venture

International Nuclear Information System (INIS)

Anon.

2002-01-01

The anglo-Dutch petroleum firm Royal Dutch/Shell has announced its intention to buy up the shares of its German partners Siemens and E.ON in their joint-venture specialized in the solar energy. If the buying up is authorized by the proper authorities, the firm will be held at 100% by Shell. Shell intends indeed to invest 500 millions to 1 milliard of dollars on 5 years in the development of renewable energies. (O.M.)

Interacting holographic dark energy with logarithmic correction

International Nuclear Information System (INIS)

Jamil, Mubasher; Farooq, M. Umar

2010-01-01

The holographic dark energy (HDE) is considered to be the most promising candidate of dark energy. Its definition is motivated from the entropy-area relation which depends on the theory of gravity under consideration. Recently a new definition of HDE is proposed with the help of quantum corrections to the entropy-area relation in the setup of loop quantum cosmology. Employing this new definition, we investigate the model of interacting dark energy and derive its effective equation of state. Finally we establish a correspondence between generalized Chaplygin gas and entropy-corrected holographic dark energy

Localized surface plasmon mediated energy transfer in the vicinity of core-shell nanoparticle

Energy Technology Data Exchange (ETDEWEB)

Shishodia, Manmohan Singh, E-mail: manmohan@gbu.ac.in; Juneja, Soniya [Department of Applied Physics, School of Vocational Studies and Applied Sciences, Gautam Buddha University, Greater Noida 201308 (India)

2016-05-28

Multipole spectral expansion based theory of energy transfer interactions between a donor and an acceptor molecule in the vicinity of a core-shell (nanoshell or core@shell) based plasmonic nanostructure is developed. In view of the diverse applications and rich plasmonic features such as tuning capability of surface plasmon (SP) frequencies, greater sensitivity to the change of dielectric environment, controllable redirection of electromagnetic radiation, closed form expressions for Energy Transfer Rate Enhancement Factor (ETREF) near core-shell particle are reported. The dependence of ETREF on different parameters is established through fitting equations, perceived to be of key importance for developing appropriate designs. The theoretical approach developed in the present work is capable of treating higher order multipoles, which, in turn, are also shown to play a crucial role in the present context. Moreover, closed form expressions derived in the present work can directly be used as formula, e.g., for designing SP based biosensors and estimating energy exchange between proteins and excitonic interactions in quantum dots.

Inner-shell corrections to the Bethe stopping-power formula evaluated from a realistic atomic model

International Nuclear Information System (INIS)

Inokuti, M.; Manson, S.T.

1985-01-01

Generalized oscillator strengths for K- and L-shell ionization have been calculated using a central potential derived from the Hartree-Slater model. In cases in which an ejected electron carries low kinetic energies, sizable differences with hydrogenic-model calculations are evident

Next-to-leading-order electroweak corrections to the production of three charged leptons plus missing energy at the LHC

Science.gov (United States)

Biedermann, Benedikt; Denner, Ansgar; Hofer, Lars

2017-10-01

The production of a neutral and a charged vector boson with subsequent decays into three charged leptons and a neutrino is a very important process for precision tests of the Standard Model of elementary particles and in searches for anomalous triple-gauge-boson couplings. In this article, the first computation of next-to-leading-order electroweak corrections to the production of the four-lepton final states μ + μ -e+ ν e, {μ}+{μ}-{e}-{\\overline{ν}}e , μ + μ - μ + ν μ , and {μ}+{μ}-{μ}-{\\overline{ν}}_{μ } at the Large Hadron Collider is presented. We use the complete matrix elements at leading and next-to-leading order, including all off-shell effects of intermediate massive vector bosons and virtual photons. The relative electroweak corrections to the fiducial cross sections from quark-induced partonic processes vary between -3% and -6%, depending significantly on the event selection. At the level of differential distributions, we observe large negative corrections of up to -30% in the high-energy tails of distributions originating from electroweak Sudakov logarithms. Photon-induced contributions at next-to-leading order raise the leading-order fiducial cross section by +2%. Interference effects in final states with equal-flavour leptons are at the permille level for the fiducial cross section, but can lead to sizeable effects in off-shell sensitive phase-space regions.

Effect of temperature on energy potential of pyrolysis products from oil palm shells

OpenAIRE

Lina María Romero Millán; María Alejandra Cruz Domínguez; Fabio Emiro Sierra Vargas

2016-01-01

Context: Taking into account that near 220 000 tons of oil palm shells are produced every year in Colombia, as a waste of the Elaeis Guineensis palm oil transformation process, the aim of this work is to determine the energy potential of oil palm shells, when transformed through slow pyrolysis process. Methods: Using a fixed bed lab scale reactor, different oil palm shells pyrolysis tests were performed between 300°C and 500°C. The effect of the temperature in the process product yield an...

Energy saving potential of long-term climate adaptive greenhouse shells

NARCIS (Netherlands)

Lee, C.; Costola, D.; Loonen, R.C.G.M.; Hensen, J.L.M.

2013-01-01

This paper describes yearly and monthly optimization of greenhouse shells. Simulations adopt a validated building energy simulation program, adapted and re-validated for simulation of commercial greenhouses, including a tomato crop model. The work focuses on multi-objective optimization of thermal

Corrections to the free-nucleon values of the single-particle matrix elements of the M1 and Gamow-Teller operators, from a comparison of shell-model predictions with sd-shell data

International Nuclear Information System (INIS)

Brown, B.A.; Wildenthal, B.H.

1983-01-01

The magnetic dipole moments of states in mirror pairs of the sd-shell nuclei and the strengths of the Gamow-Teller beta decays which connect them are compared with predictions based on mixed-configuration shell-model wave functions. From this analysis we extract the average effective values of the single-particle matrix elements of the l, s, and [Y/sup( 2 )xs]/sup( 1 ) components of the M1 and Gamow-Teller operators acting on nucleons in the 0d/sub 5/2/, 1s/sub 1/2/, and 0d/sub 3/2/ orbits. These results are compared with the recent calculations by Towner and Khanna of the corrections to the free-nucleon values of these matrix elements which arise from the effects of isobar currents, mesonic-exchange currents, and mixing with configurations outside the sd shell

Photon energy-fluence correction factor in low energy brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Antunes, Paula C.G.; Yoriyaz, Hélio [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Vijande, Javier; Giménez-Alventosa, Vicent; Ballester, Facundo, E-mail: pacrisguian@gmail.com [Department of Atomic, Molecular, and Nuclear Physics and Instituto de Física Corpuscular (UV-CSIC), University of Valencia (Spain)

2017-07-01

The AAPM TG-43 brachytherapy dosimetry formalism has become a standard for brachytherapy dosimetry worldwide; it implicitly assumes that charged-particle equilibrium (CPE) exists for the determination of absorbed dose to water at different locations. At the time of relating dose to tissue and dose to water, or vice versa, it is usually assumed that the photon fluence in water and in tissues are practically identical, so that the absorbed dose in the two media can be related by their ratio of mass energy-absorption coefficients. The purpose of this work is to study the influence of photon energy-fluence in different media and to evaluate a proposal for energy-fluence correction factors for the conversion between dose-to-tissue (D{sub tis}) and dose-to-water (D{sub w}). State-of-the art Monte Carlo (MC) calculations are used to score photon fluence differential in energy in water and in various human tissues (muscle, adipose and bone) in two different codes, MCNP and PENELOPE, which in all cases include a realistic modeling of the {sup 125}I low-energy brachytherapy seed in order to benchmark the formalism proposed. A correction is introduced that is based on the ratio of the water-to-tissue photon energy-fluences using the large-cavity theory. In this work, an efficient way to correlate absorbed dose to water and absorbed dose to tissue in brachytherapy calculations at clinically relevant distances for low-energy photon emitting seed is proposed. The energy-fluence based corrections given in this work are able to correlate absorbed dose to tissue and absorbed dose to water with an accuracy better than 0.5% in the most critical cases. (author)

Photon energy-fluence correction factor in low energy brachytherapy

International Nuclear Information System (INIS)

Antunes, Paula C.G.; Yoriyaz, Hélio; Vijande, Javier; Giménez-Alventosa, Vicent; Ballester, Facundo

2017-01-01

The AAPM TG-43 brachytherapy dosimetry formalism has become a standard for brachytherapy dosimetry worldwide; it implicitly assumes that charged-particle equilibrium (CPE) exists for the determination of absorbed dose to water at different locations. At the time of relating dose to tissue and dose to water, or vice versa, it is usually assumed that the photon fluence in water and in tissues are practically identical, so that the absorbed dose in the two media can be related by their ratio of mass energy-absorption coefficients. The purpose of this work is to study the influence of photon energy-fluence in different media and to evaluate a proposal for energy-fluence correction factors for the conversion between dose-to-tissue (D tis ) and dose-to-water (D w ). State-of-the art Monte Carlo (MC) calculations are used to score photon fluence differential in energy in water and in various human tissues (muscle, adipose and bone) in two different codes, MCNP and PENELOPE, which in all cases include a realistic modeling of the 125 I low-energy brachytherapy seed in order to benchmark the formalism proposed. A correction is introduced that is based on the ratio of the water-to-tissue photon energy-fluences using the large-cavity theory. In this work, an efficient way to correlate absorbed dose to water and absorbed dose to tissue in brachytherapy calculations at clinically relevant distances for low-energy photon emitting seed is proposed. The energy-fluence based corrections given in this work are able to correlate absorbed dose to tissue and absorbed dose to water with an accuracy better than 0.5% in the most critical cases. (author)

Generalized Møller-Plesset Multiconfiguration Perturbation Theory Applied to an Open-Shell Antisymmetric Product of Strongly Orthogonal Geminals Reference Wave Function.

Science.gov (United States)

Tarumi, Moto; Kobayashi, Masato; Nakai, Hiromi

2012-11-13

The antisymmetric product of strongly orthogonal geminals (APSG) method is a wave function theory that can effectively treat the static electron correlation. Recently, we proposed the open-shell APSG method using one-electron orbitals for open-shell parts. In this paper, we have extended the perturbation correction to the open-shell APSG calculations through Møller-Plesset-type multiconfiguration perturbation theory (MP-MCPT). Numerical applications demonstrate that the present open-shell MP-MCPT can reasonably reproduce the dissociation energies or equilibrium distances for open-shell systems.

Two-loop O(ααs) corrections to the on-shell fermion propagator in the standard model

International Nuclear Information System (INIS)

Eiras, Dolors; Steinhauser, Matthias

2006-01-01

In this paper we consider mixed two-loop electroweak corrections to the top quark propagator in the Standard Model. In particular, we compute the on-shell renormalization constant for the mass and wave function, which constitute building blocks for many physical processes. The results are expressed in terms of master integrals. For the latter practical approximations are derived. In the case of the mass renormalization constant we find agreement with the results in the literature

L-shell x-ray fluorescence computed tomography (XFCT) imaging of Cisplatin

International Nuclear Information System (INIS)

Bazalova, Magdalena; Ahmad, Moiz; Pratx, Guillem; Xing, Lei

2014-01-01

X-ray fluorescence computed tomography (XFCT) imaging has been focused on the detection of K-shell x-rays. The potential utility of L-shell x-ray XFCT is, however, not well studied. Here we report the first Monte Carlo (MC) simulation of preclinical L-shell XFCT imaging of Cisplatin. We built MC models for both L- and K-shell XFCT with different excitation energies (15 and 30 keV for L-shell and 80 keV for K-shell XFCT). Two small-animal sized imaging phantoms of 2 and 4 cm diameter containing a series of objects of 0.6 to 2.7 mm in diameter at 0.7 to 16 mm depths with 10 to 250 µg mL −1  concentrations of Pt are used in the study. Transmitted and scattered x-rays were collected with photon-integrating transmission detector and photon-counting detector arc, respectively. Collected data were rearranged into XFCT and transmission CT sinograms for image reconstruction. XFCT images were reconstructed with filtered back-projection and with iterative maximum-likelihood expectation maximization without and with attenuation correction. While K-shell XFCT was capable of providing an accurate measurement of Cisplatin concentration, its sensitivity was 4.4 and 3.0 times lower than that of L-shell XFCT with 15 keV excitation beam for the 2 cm and 4 cm diameter phantom, respectively. With the inclusion of excitation and fluorescence beam attenuation correction, we found that L-shell XFCT was capable of providing fairly accurate information of Cisplatin concentration distribution. With a dose of 29 and 58 mGy, clinically relevant Cisplatin Pt concentrations of 10 µg mg −1  could be imaged with L-shell XFCT inside a 2 cm and 4 cm diameter object, respectively. (paper)

Calculation of the Coulomb nuclear energy for the 1fsub(7/2) shell

International Nuclear Information System (INIS)

Kaminski, V.A.; Shpikovski, S.

1980-01-01

Calculated was the Coulomb energy for nuclei with half-filled 1fsub(7/2) shell i.e. for configurations, where quasiparticle basis can serve as a total basis for precise calculations. Presented are calculation results of vector and tensor components of the Coulomb energy for Ca-Se-Ti-V isobaric pairs, as well as experimental and theoretical values for the Coulomb displacements. To estimate the Coulomb energies used were wave functions of a Hamiltonian taking account of pair and quadrupole interactions. There is good agreement with experimental data. Quasiparticle consideration is useful for calculating matrix elements of half-filled shells and for the cases of such an isospin value, where the technique of genealogical coefficients becomes extremely cumbersome

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

International Nuclear Information System (INIS)

Ahalpara, D.P.

1979-01-01

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

Energy dependence of photon-induced L shell x-ray intensity ratios in Ta and W

Energy Technology Data Exchange (ETDEWEB)

Shatendra, K; Allawadhi, K L; Sood, B S

1984-02-01

The L shell x-ray intensity ratios have been measured for the elements Ta and W by photoionization of L shell electrons in the photon energy region 14 <= E <= 44 keV. The experimental results are compared with those calculated at the photon energies used in the present measurements. The measured values show fairly good agreement with the calculated values within the experimental uncertainties. 11 references, 7 figures.

Dominant thermogravimetric signatures of lignin in cashew shell as compared to cashew shell cake.

Science.gov (United States)

Gangil, Sandip

2014-03-01

Dominant thermogravimetric signatures related to lignin were observed in cashew shell as compared to these signatures in cashew shell cake. The phenomenon of weakening of lignin from cashew shell to cashew shell cake was explained on the basis of changes in the activation energies. The pertinent temperature regimes responsible for the release of different constituents of both the bio-materials were identified and compared. The activation energies of cashew shell and cashew shell cake were compared using Kissinger-Akahira-Sunose method. Thermogravimetric profiling of cashew shell and cashew shell cake indicated that these were different kinds of bio-materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

Shell energy scenarios to 2050. Signals and Signposts. An era of volatile transitions

International Nuclear Information System (INIS)

2011-01-01

For 40 years, Shell has drawn on its scenarios to enhance business decisions and its ability to respond to change. Our most recent scenarios also contributed positively to the global public debate on energy and the environment. But the financial crash, the deepest economic slump in 70 years, and a patchy and fragile recovery have changed the world dramatically. We must consider how these events may or may not have altered our energy outlooks. Signals and Signposts offers our best understanding about the changes brought by the global financial and economic crisis. Internally, we have been using Recession and Recovery scenarios since September 2008. The two outlooks (Severe-yet-Sharp and Deeper-and-Longer) have, so far, bracketed actual developments. We have also drawn on a supplementary but unlikely scenario, Depression 2.0. These scenarios continue to provide useful insights and we draw on them in this booklet. Despite the economic turbulence, the fundamental drivers and uncertainties explored in our Shell Energy Scenarios to 2050 remain fully relevant. Signals and Signposts highlights significant additional factors and should be read as a companion to our Scramble and Blueprints energy scenarios, which can be downloaded from www.shell.com/scenarios. An overview is in the Appendix.

Facile and controllable construction of vanadium pentoxide@conducting polymer core/shell nanostructures and their thickness-dependent synergistic energy storage properties

International Nuclear Information System (INIS)

Tong, Zhongqiu; Liu, Shikun; Li, Xingang; Ding, Yanbo; Zhao, Jiupeng; Li, Yao

2016-01-01

Graphical abstract: Here, we report a novel approach to prepare metal oxide@conducting polymer core/shell hybrids with controlled shell thickness and morphology, and the influence of PANI shell thickness on the electrochemical performance of V 2 O 5 @PANI core/shell hybrids is systematically investigated. Thickness-dependent synergistic electron transport, Li-ion diffusion distance, and shell mechanical strength mechanisms are proposed. - Highlights: • Thickness- and morphology-controlled V 2 O 5 /PANI core/shell hybrid nanofibers are fabricated. • The enhancement of energy storage performance of core/shell hybrids varies with the shell thickness. • Thickness-dependent synergistic electron transport, Li-ion diffusion distances, and shell mechanical strength mechanisms are proposed. - Abstract: Thickness- and morphology-controlled vanadium pentoxide/polyaniline (V 2 O 5 /PANI) core/shell hybrid nanofibers are fabricated by electropolymerization of PANI on V 2 O 5 nanofibers for enhanced energy storage. By simply adjusting the electrodeposition time, the thickness of the PANI shells can be controlled from 5 nm to 47 nm, and the morphology can be changed from coaxial to branched. The influence of shell thickness on the improved Li-ion storage performance of the V 2 O 5 /PANI core/shell nanofibers is systematically investigated, and this enhancement of charge capability and cycling stability strongly varies with the shell thickness. Thickness-dependent synergistic electron transport, Li-ion diffusion distances, and shell mechanical strength mechanisms are also proposed. These results provide meaningful references for developing new functional core/shell materials and high-performance energy storage composite materials.

Fermi energy dependence of the optical emission in core/shell InAs nanowire homostructures

Science.gov (United States)

Möller, M.; Oliveira, D. S.; Sahoo, P. K.; Cotta, M. A.; Iikawa, F.; Motisuke, P.; Molina-Sánchez, A.; de Lima, M. M., Jr.; García-Cristóbal, A.; Cantarero, A.

2017-07-01

InAs nanowires grown by vapor-liquid-solid (VLS) method are investigated by photoluminescence. We observe that the Fermi energy of all samples is reduced by ˜20 meV when the size of the Au nanoparticle used for catalysis is increased from 5 to 20 nm. Additional capping with a thin InP shell enhances the optical emission and does not affect the Fermi energy. The unexpected behavior of the Fermi energy is attributed to the differences in the residual donor (likely carbon) incorporation in the axial (low) and lateral (high incorporation) growth in the VLS and vapor-solid (VS) methods, respectively. The different impurity incorporation rate in these two regions leads to a core/shell InAs homostructure. In this case, the minority carriers (holes) diffuse to the core due to the built-in electric field created by the radial impurity distribution. As a result, the optical emission is dominated by the core region rather than by the more heavily doped InAs shell. Thus, the photoluminescence spectra and the Fermi energy become sensitive to the core diameter. These results are corroborated by a theoretical model using a self-consistent method to calculate the radial carrier distribution and Fermi energy for distinct diameters of Au nanoparticles.

Dossier Shell Eco-Marathon; Dossier Shell Eco-Marathon

Energy Technology Data Exchange (ETDEWEB)

Matla, P.

2012-05-15

Three articles address subjects concerning the annual race with highly energy efficient cars: the Shell Eco-Marathon. [Dutch] In 3 artikelen wordt aandacht besteed aan de ontwerpen voor de jaarlijkse race met superzuinige auto's, de Shell Eco-Marathon.

Correction of the horizontal closed orbit at all energies

International Nuclear Information System (INIS)

Degueurce, L.; Nakach, A.

The method followed is accomplished in two steps. At average energy, the closed orbit is corrected by a remote realignment of the focusing quadrupoles by a known quantity. This closed orbit, created by the position adjustment of the quadrupoles, is valid during the whole cycle; but at low energy level, a closed orbit is added because of constant currents or parasitic fields whose effects decrease as the energy level increases. This residual orbit is corrected during the injection by dipolar correction fields, located on the inside of the quadrupoles and fed by direct currents. Therefore, the closed orbit resulting from the superposition of the two types of corrections and defects is brought back to +- 2.5 mm with respect to the center of the quadrupoles

Stopping powers of Zr, Pd, Cd, In and Pb for 6.5 MeV protons and mean excitation energies

International Nuclear Information System (INIS)

Ishiwari, R.; Shiomi, N.; Sakamoto, N.

1983-01-01

Stopping powers of Zr, Pd, Cd, In and Pb have been measured for 6.5 MeV protons. Mean excitation energies have been extracted from the stopping power data by taking into account Bloch correction and Z 1 3 correction. For the shell correction the Bonderup shell correction has been used. The results agree fairly well with those of other authors

Facile and low energy consumption synthesis of microencapsulated phase change materials with hybrid shell for thermal energy storage

Science.gov (United States)

Wang, Hao; Zhao, Liang; Chen, Lijie; Song, Guolin; Tang, Guoyi

2017-12-01

We designed a photocurable pickering emulsion polymerization to create microencapsulated phase change materials (MicroPCM) with polymer-silica hybrid shell. The emulsion was stabilized by modified SiO2 particles without any surfactant or dispersant. The polymerization process can be carried out at ambient temperature only for 5 min ultraviolet radiation, which is a low-energy procedure. The resultant capsules were shown a good core-shell structure and uniform in size. The surface of the microcapsules was covered by SiO2 particles. According to the DSC and TGA examinations, the microcapsules has good thermal energy storage-release performance, enhanced thermal reliability and thermal stability. When ratio of MMA/n-octadecane was 1.5/1.5. The encapsulation efficiency of the microcapsules reached 62.55%, accompanied with 122.31 J/g melting enthalpy. The work is virtually applicable to the construction of a wide variety of organic-inorganic hybrid shell MicroPCM. Furthermore, with the application of this method, exciting opportunities may arise for realizing rapid, continuous and large-scale industrial preparation of MicroPCM.

Zero-point energies in the two-center shell model

International Nuclear Information System (INIS)

Reinhard, P.G.

1975-01-01

The zero-point energies (ZPE) contained in the potential-energy surfaces (PES) of a two-center shell model are evaluated. For the c.m. motion of the system as a whole the kinetic ZPE was found to be negligible, whereas it varies appreciably for the rotational and oscillation modes (about 5-9MeV). For the latter two modes the ZPE also depends sensitively on the changing pairing structure, which can induce strong local fluctuations, particularly in light nuclei. The potential ZPE is very small for heavy nuclei, but might just become important in light nuclei. (Auth.)

Separable expansions of the NN t-matrix via exact half off the energy shell methods

International Nuclear Information System (INIS)

Pisent, G.; Amos, K.; Dortmans, P.J.

1992-01-01

Recently a method was proposed by which one can obtain rank 1 (for uncoupled channels) and rank 2 (for coupled channels), energy dependent t-matrix representations which are exact on- and half off of the energy shell. Fully off shell, this representation, though accurate at low energies, is flawed. For uncoupled channels, if the phase shift passes through zero, the representation has a pathology. Two methods which overcome this are investigated one due to Haberzettl which was extended to coupled channels, and the second which is based upon selective combination of the elements of Sturmian expansions. All methods of separation over a range of energies up to 250 MeV for the 1 S 0 and 3 S 1 channels are compared with the Paris interaction. Special attention is paid to the convergence of the higher order Haberzettl expansion and to the comparison of the extended methods for energies around the zero phase shift pathology for the 1 S 0 channel. The method describes well the fully off-shell properties of the t-matrices up to quite high energies, while keeping the rank of the separation as low as possible in order to be used in three or more body calculations. 39 refs., 10 figs

Multi-shell spherical GaAs /AlxGa1-x As quantum dot shells-size distribution as a mechanism to generate intermediate band energy levels

Science.gov (United States)

Rodríguez-Magdaleno, K. A.; Pérez-Álvarez, R.; Martínez-Orozco, J. C.; Pernas-Salomón, R.

2017-04-01

In this work the generation of an intermediate band of energy levels from multi-shell spherical GaAs /AlxGa1-x As quantum dot shells-size distribution is reported. Within the effective mass approximation the electronic structure of a GaAs spherical quantum-dot surrounded by one, two and three shells is studied in detail using a numerically stable transfer matrix method. We found that a shells-size distribution characterized by continuously wider GaAs domains is a suitable mechanism to generate the intermediate band whose width is also dependent on the Aluminium concentration x. Our results suggest that this effective mechanism can be used for the design of wider intermediate band than reported in other quantum systems with possible solar cells enhanced performance.

Finite-size corrections to the free energies of crystalline solids

NARCIS (Netherlands)

Polson, J.M.; Trizac, E.; Pronk, S.; Frenkel, D.

2000-01-01

We analyze the finite-size corrections to the free energy of crystals with a fixed center of mass. When we explicitly correct for the leading (ln N/N) corrections, the remaining free energy is found to depend linearly on 1/N. Extrapolating to the thermodynamic limit (N → ∞), we estimate the free

Enhanced energy storage and suppressed dielectric loss in oxide core-shell-polyolefin nanocomposites by moderating internal surface area and increasing shell thickness

Energy Technology Data Exchange (ETDEWEB)

Fredin, Lisa A.; Li, Zhong; Ratner, Mark A.; Marks, Tobin J. [Department of Chemistry Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Lanagan, Michael T. [Center for Dielectric Studies, Materials Research Institute, The Pennsylvania State University, University Park, PA 16802-4800 (United States)

2012-11-20

Dielectric loss in metal oxide core/Al{sub 2}O{sub 3} shell polypropylene nanocomposites scales with the particle surface area. By moderating the interfacial surface area between the phases and using increasing shell thicknesses, dielectric loss is significantly reduced, and thus the energy stored within, and recoverable from, capacitors fabricated from these materials is significantly increased, to as high as 2.05 J/cm{sup 3}. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Off-energy-shell variations of two-nucleon transition matrix and three-nucleon problem

International Nuclear Information System (INIS)

Stingl, M.; Sauer, P.U.

1975-01-01

For a schematic three-nucleon problem, approximate analytic expressions are derived for the functional derivatives of measurable three-particle quantities with respect to off-shell variations of the triplet-s two-nucleon transition matrix. Those quantities include neutron-deuteron scattering lengths, trinucleon binding energies, and the 3 He charge form-factor minimum; correlations between off-shell changes in the latter two are discussed. An indication is given how results of this kind may be to decide whether or not a given set of discrepancies between calculated and experimental three-nucleon observables can be reconciled in terms of off-shell variations of a nonretarded hermitean two-nucleon interaction. The treatment is not restricted to special classes of phase-shift equivalent potentials or phase-shift preserving transformations but instead makes use of a systematic parameterization of off-shell variations in terms of symmetric rational approximants of increasing order

Stability of Thin Shell Wormholes in Born-Infeld Theory Supported by Polytropic Phantom Energy

Energy Technology Data Exchange (ETDEWEB)

Eid, Ali [Cairo University, Giza (Egypt)

2017-02-15

In the framework of the Darmois-Israel formalism, the dynamical equations of motion of spherically-symmetric thin-shell wormholes supported by a polytropic phantom energy in Einstein-Born-Infeld theory are constructed. A stability analysis of the spherically-symmetric thin-shell wormhole by using the standard potential method is carried out. The existence of stable, static solutions depends on the values of some parameters.

ENERGY CORRECTION FOR HIGH POWER PROTON/H MINUS LINAC INJECTORS.

Energy Technology Data Exchange (ETDEWEB)

RAPARIA, D.; LEE, Y.Y.; WEI, J.

2005-05-16

High-energy proton/H minus energy (> GeV) linac injector suffer from energy jitter due to RF amplitude and phase stability. Especially in high power injectors this energy jitter result beam losses more than 1 W/m that require for hand on maintenance. Depending upon the requirements for next accelerator in the chain, this energy jitter may or may not require to be corrected. This paper will discuss the sources of this energy jitter, correction schemes with specific examples.

Core-Shell Al-Polytetrafluoroethylene (PTFE) Configurations to Enhance Reaction Kinetics and Energy Performance for Nanoenergetic Materials.

Science.gov (United States)

Wang, Jun; Qiao, Zhiqiang; Yang, Yuntao; Shen, Jinpeng; Long, Zhang; Li, Zhaoqian; Cui, Xudong; Yang, Guangcheng

2016-01-04

The energy performance of solid energetic materials (Al, Mg, etc.) is typically restricted by a natural passivation layer and the diffusion-limited kinetics between the oxidizer and the metal. In this work, we use polytetrafluoroethylene (PTFE) as the fluorine carrier and the shielding layer to construct a new type of nano-Al based fuels. The PTFE shell not only prevents nano-Al layers from oxidation, but also assists in enhancing the reaction kinetics, greatly improving the stability and reactivity of fuels. An in situ chemical vapor deposition combined with the electrical explosion of wires (EEW) method is used to fabricate core-shell nanostructures. Studies show that by controlling the stoichiometric ratio of the precursors, the morphology of the PTFE shell and the energy performance can be easily tuned. The resultant composites exhibit superior energy output characters than that of their physically mixed Al/PTFE counterparts. This synthetic strategy might provide a general approach to prepare other high-energy fuels (Mg, Si). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Energy transfer in nanowire solar cells with photon-harvesting shells

KAUST Repository

Peters, C. H.

2009-01-01

The concept of a nanowire solar cell with photon-harvesting shells is presented. In this architecture, organic molecules which absorb strongly in the near infrared where silicon absorbs weakly are coupled to silicon nanowires (SiNWs). This enables an array of 7-μm -long nanowires with a diameter of 50 nm to absorb over 85% of the photons above the bandgap of silicon. The organic molecules are bonded to the surface of the SiNWs forming a thin shell. They absorb the low-energy photons and subsequently transfer the energy to the SiNWs via Förster resonant energy transfer, creating free electrons and holes within the SiNWs. The carriers are then separated at a radial p-n junction in a nanowire and extracted at the respective electrodes. The shortness of the nanowires is expected to lower the dark current due to the decrease in p-n junction surface area, which scales linearly with wire length. The theoretical power conversion efficiency is 15%. To demonstrate this concept, we measure a 60% increase in photocurrent from a planar silicon-on-insulator diode when a 5 nm layer of poly[2-methoxy-5-(2′ -ethyl-hexyloxy)-1,4-phenylene vinylene is applied to the surface of the silicon. This increase is in excellent agreement with theoretical predictions. © 2009 American Institute of Physics.

Ab initio thermochemistry using optimal-balance models with isodesmic corrections: The ATOMIC protocol

Science.gov (United States)

Bakowies, Dirk

2009-04-01

A theoretical composite approach, termed ATOMIC for Ab initio Thermochemistry using Optimal-balance Models with Isodesmic Corrections, is introduced for the calculation of molecular atomization energies and enthalpies of formation. Care is taken to achieve optimal balance in accuracy and cost between the various components contributing to high-level estimates of the fully correlated energy at the infinite-basis-set limit. To this end, the energy at the coupled-cluster level of theory including single, double, and quasiperturbational triple excitations is decomposed into Hartree-Fock, low-order correlation (MP2, CCSD), and connected-triples contributions and into valence-shell and core contributions. Statistical analyses for 73 representative neutral closed-shell molecules containing hydrogen and at least three first-row atoms (CNOF) are used to devise basis-set and extrapolation requirements for each of the eight components to maintain a given level of accuracy. Pople's concept of bond-separation reactions is implemented in an ab initio framework, providing for a complete set of high-level precomputed isodesmic corrections which can be used for any molecule for which a valence structure can be drawn. Use of these corrections is shown to lower basis-set requirements dramatically for each of the eight components of the composite model. A hierarchy of three levels is suggested for isodesmically corrected composite models which reproduce atomization energies at the reference level of theory to within 0.1 kcal/mol (A), 0.3 kcal/mol (B), and 1 kcal/mol (C). Large-scale statistical analysis shows that corrections beyond the CCSD(T) reference level of theory, including coupled-cluster theory with fully relaxed connected triple and quadruple excitations, first-order relativistic and diagonal Born-Oppenheimer corrections can normally be dealt with using a greatly simplified model that assumes thermoneutral bond-separation reactions and that reduces the estimate of these

Technical Note: Effect of explicit M and N-shell atomic transitions on a low-energy x-ray source

Energy Technology Data Exchange (ETDEWEB)

Watson, Peter G. F., E-mail: peter.watson@mail.mcgill.ca; Seuntjens, Jan [Medical Physics Unit, McGill University, Montreal, Quebec H4A 3J1 (Canada)

2016-04-15

Purpose: In EGSnrc, atomic transitions to and from the M and N-shells are treated in an average way by default. This approach is justified in which the energy difference between explicit and average M and N-shell binding energies is less than 1 keV, and for most applications can be considered negligible. However, for simulations of low energy x-ray sources on thin, high-Z targets, characteristic x-rays can make up a significant portion of the source spectra. As of release V4-2.4.0, EGSnrc has included an option to enable a more complete algorithm of all atomic transitions available in the EADL compilation. In this paper, the effect of M and N-shell averaging on the calculation of half-value layer (HVL) and relative depth dose (RDD) curve of a 50 kVp intraoperative x-ray tube with a thin gold target was investigated. Methods: A 50 kVp miniature x-ray source with a gold target (The INTRABEAM System, Carl Zeiss, Germany) was modeled with the EGSnrc user code cavity, both with and without M and N-shell averaging. From photon fluence spectra simulations, the source HVLs were determined analytically. The same source model was then used with egs-chamber to calculate RDD curves in water. Results: A 4% increase of HVL was reported when accounting for explicit M and N-shell transitions, and up to a 9% decrease in local relative dose for normalization at 3 mm depth in water. Conclusions: The EGSnrc default of using averaged M and N-shell binding energies has an observable effect on the HVL and RDD of a low energy x-ray source with high-Z target. For accurate modeling of this class of devices, explicit atomic transitions should be included.

Radiative corrections to high-energy neutrino scattering

International Nuclear Information System (INIS)

Rujula, A. de; Petronzio, R.; Savoy-Navarro, A.

1979-01-01

Motivated by precise neutrino experiments, the electromagnetic radiative corrections to the data are reconsidered. The usefulness is investigated and the simplicity demonstrated of the 'leading log' approximation: the calculation to order α ln (Q/μ), α ln (Q/msub(q)). Here Q is an energy scale of the overall process, μ is the lepton mass and msub(q) is a hadronic mass, the effective quark mass in a parton model. The leading log radiative corrections to dsigma/dy distributions and to suitably interpreted dsigma/dx distributions are quark-mass independent. The authors improve upon the conventional leading log approximation and compute explicitly the largest terms that lie beyond the leading log level. In practice this means that the model-independent formulae, though approximate, are likely to be excellent estimates everywhere except at low energy or very large y. It is pointed out that radiative corrections to measurements of deviations from the Callan-Gross relation and to measurements of the 'sea' constituency of nucleons are gigantic. The QCD inspired study of deviations from scaling is of particular interest. The authors compute, beyond the leading log level, the radiative corrections of the QCD predictions. (Auth.)

Off-shell CHY amplitudes

Energy Technology Data Exchange (ETDEWEB)

Lam, C.S., E-mail: Lam@physics.mcgill.ca [Department of Physics, McGill University, Montreal, Q.C., H3A 2T8 (Canada); Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Yao, York-Peng, E-mail: yyao@umich.edu [Department of Physics, The University of Michigan Ann Arbor, MI 48109 (United States)

2016-06-15

The Cachazo–He–Yuan (CHY) formula for on-shell scattering amplitudes is extended off-shell. The off-shell amplitudes (amputated Green's functions) are Möbius invariant, and have the same momentum poles as the on-shell amplitudes. The working principles which drive the modifications to the scattering equations are mainly Möbius covariance and energy momentum conservation in off-shell kinematics. The same technique is also used to obtain off-shell massive scalars. A simple off-shell extension of the CHY gauge formula which is Möbius invariant is proposed, but its true nature awaits further study.

Ground state energy and wave function of an off-centre donor in spherical core/shell nanostructures: Dielectric mismatch and impurity position effects

Energy Technology Data Exchange (ETDEWEB)

Ibral, Asmaa [Equipe d’Optique et Electronique du Solide, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida 24000 (Morocco); Laboratoire d’Instrumentation, Mesure et Contrôle, Département de Physique, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida (Morocco); Zouitine, Asmae [Département de Physique, Ecole Nationale Supérieure d’Enseignement Technique, Université Mohammed V Souissi, B.P. 6207 Rabat-Instituts, Rabat (Morocco); Assaid, El Mahdi, E-mail: eassaid@yahoo.fr [Equipe d’Optique et Electronique du Solide, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida 24000 (Morocco); Laboratoire d’Instrumentation, Mesure et Contrôle, Département de Physique, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida (Morocco); Feddi, El Mustapha [Département de Physique, Ecole Nationale Supérieure d’Enseignement Technique, Université Mohammed V Souissi, B.P. 6207 Rabat-Instituts, Rabat (Morocco); and others

2014-09-15

Ground state energy and wave function of a hydrogen-like off-centre donor impurity, confined anywhere in a ZnS/CdSe spherical core/shell nanostructure are determined in the framework of the envelope function approximation. Conduction band-edge alignment between core and shell of nanostructure is described by a finite height barrier. Dielectric constant mismatch at the surface where core and shell materials meet is taken into account. Electron effective mass mismatch at the inner surface between core and shell is considered. A trial wave function where coulomb attraction between electron and off-centre ionized donor is used to calculate ground state energy via the Ritz variational principle. The numerical approach developed enables access to the dependence of binding energy, coulomb correlation parameter, spatial extension and radial probability density with respect to core radius, shell radius and impurity position inside ZnS/CdSe core/shell nanostructure.

Ground state energy and wave function of an off-centre donor in spherical core/shell nanostructures: Dielectric mismatch and impurity position effects

International Nuclear Information System (INIS)

Ibral, Asmaa; Zouitine, Asmae; Assaid, El Mahdi; Feddi, El Mustapha

2014-01-01

Ground state energy and wave function of a hydrogen-like off-centre donor impurity, confined anywhere in a ZnS/CdSe spherical core/shell nanostructure are determined in the framework of the envelope function approximation. Conduction band-edge alignment between core and shell of nanostructure is described by a finite height barrier. Dielectric constant mismatch at the surface where core and shell materials meet is taken into account. Electron effective mass mismatch at the inner surface between core and shell is considered. A trial wave function where coulomb attraction between electron and off-centre ionized donor is used to calculate ground state energy via the Ritz variational principle. The numerical approach developed enables access to the dependence of binding energy, coulomb correlation parameter, spatial extension and radial probability density with respect to core radius, shell radius and impurity position inside ZnS/CdSe core/shell nanostructure

Shell correction approach to nuclear state densities and the competition between fission and neutron emission of 210Po

International Nuclear Information System (INIS)

Gottschalk, P.A.; Ledergerber, T.

Starting from the Hartree-Fock approximation to the grand-canonical partition function we formulate a consistent renormalization of the ground state energy and the intrinsic state density as a function of deformation. The relationship to recent selfconsistent temperature dependent calculations is discussed. The competition between fission and neutron emission, GAMMA sub(f)/GAMMA sub(n)(E), of 210 Po is studied within the framework of the statistical theory as an example. Calculations using renormalized state densities are compared with usual shell model calculations and experimental data. It is found that the usual calculations reflect the incorrect uniform deformation dependence of the shell model spectral function. Important changes due to renormalization are found: a rapid change of the shape of the transition state at approximately 45 MeV excitation energy, GAMMA sub(f)/GAMMA sub(n)(E) remains smaller than unity for all excitation energies and the deformation of the transition state increases after the 'shape transition' at 45 MeV monotonically towards the liquid drop saddle point deformation with a tendency towards slightly larger deformations. (author)

EVOLUTION OF HIGH-ENERGY PARTICLE DISTRIBUTION IN MATURE SHELL-TYPE SUPERNOVA REMNANTS

Energy Technology Data Exchange (ETDEWEB)

Zeng, Houdun; Xin, Yuliang; Liu, Siming; Zhang, Shuinai [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Jokipii, J. R. [University of Arizona, Tucson, Arizona, 85721 (United States); Zhang, Li, E-mail: zhd@pmo.ac.cn, E-mail: liusm@pmo.ac.cn [Key Laboratory of Astroparticle Physics of Yunnan Province, Kunming, 650091 (China)

2017-01-10

Multi-wavelength observations of mature supernova remnants (SNRs), especially with recent advances in γ -ray astronomy, make it possible to constrain energy distribution of energetic particles within these remnants. In consideration of the SNR origin of Galactic cosmic rays and physics related to particle acceleration and radiative processes, we use a simple one-zone model to fit the nonthermal emission spectra of three shell-type SNRs located within 2° on the sky: RX J1713.7−3946, CTB 37B, and CTB 37A. Although radio images of these three sources all show a shell (or half-shell) structure, their radio, X-ray, and γ -ray spectra are quite different, offering an ideal case to explore evolution of energetic particle distribution in SNRs. Our spectral fitting shows that (1) the particle distribution becomes harder with aging of these SNRs, implying a continuous acceleration process, and the particle distributions of CTB 37A and CTB 37B in the GeV range are harder than the hardest distribution that can be produced at a shock via the linear diffusive shock particle acceleration process, so spatial transport may play a role; (2) the energy loss timescale of electrons at the high-energy cutoff due to synchrotron radiation appears to be always a bit (within a factor of a few) shorter than the age of the corresponding remnant, which also requires continuous particle acceleration; (3) double power-law distributions are needed to fit the spectra of CTB 37B and CTB 37A, which may be attributed to shock interaction with molecular clouds.

Valence shell photoionization energies and cross-sections of NF sub 3 and PF sub 3

CERN Document Server

Jürgensen, A

2003-01-01

Relative outer valence shell ionization potentials and cross-sections were determined for the isostructural, Group 15, trifluorides NF sub 3 and PF sub 3 in the gas phase using synchrotron radiation. Excitation photon energies ranged from 70 to 160 eV. The experimental spectra were assigned and cross-sections analyzed with the aid of both MS-X alpha and ab initio calculations. Spectral differences in peak energies and relative intensities are related to structural and electronic differences between these two fluoride molecules. Valence shell ionization potentials were compared to calculated values obtained by several different methods. The partial photoionization cross-sections for each orbital were obtained as a function of excitation energy and compared to theoretical results obtained with the X alpha method.

Zero-point energies in the two-center shell model. II

International Nuclear Information System (INIS)

Reinhard, P.-G.

1978-01-01

The zero-point energy (ZPE) contained in the potential-energy surface of a two-center shell model (TCSM) is evaluated. In extension of previous work, the author uses here the full TCSM with l.s force, smoothing and asymmetry. The results show a critical dependence on the height of the potential barrier between the centers. The ZPE turns out to be non-negligible along the fission path for 236 U, and even more so for lighter systems. It is negligible for surface quadrupole motion and it is just on the fringe of being negligible for motion along the asymmetry coordinate. (Auth.)

Deformed potential energy of $^{263}Db$ in a generalized liquid drop model

CERN Document Server

Chen Bao Qiu; Zhao Yao Lin; 10.1088/0256-307X/20/11/009

2003-01-01

The macroscopic deformed potential energy for super-heavy nuclei /sup 263/Db, which governs the entrance and alpha decay channels, is determined within a generalized liquid drop model (GLDM). A quasi- molecular shape is assumed in the GLDM, which includes volume-, surface-, and Coulomb-energies, proximity effects, mass asymmetry, and an accurate nuclear radius. The microscopic single particle energies derived from a shell model in an axially deformed Woods- Saxon potential with a quasi-molecular shape. The shell correction is calculated by the Strutinsky method. The total deformed potential energy of a nucleus can be calculated by the macro-microscopic method as the summation of the liquid-drop energy and the Strutinsky shell correction. The theory is applied to predict the deformed potential energy of the experiment /sup 22/Ne+/sup 241/Am to /sup 263/Db* to /sup 259/Db+4 n, which was performed on the Heavy Ion Accelerator in Lanzhou. It is found that the neck in the quasi-molecular shape is responsible for t...

Unitarity corrections and high field strengths in high energy hard collisions

International Nuclear Information System (INIS)

Kovchegov, Y.V.; Mueller, A.H.

1997-01-01

Unitarity corrections to the BFKL description of high energy hard scattering are viewed in large N c QCD in light-cone quantization. In a center of mass frame unitarity corrections to high energy hard scattering are manifestly perturbatively calculable and unrelated to questions of parton saturation. In a frame where one of the hadrons is initially at rest unitarity corrections are related to parton saturation effects and involve potential strengths A μ ∝1/g. In such a frame we describe the high energy scattering in terms of the expectation value of a Wilson loop. The large potentials A μ ∝1/g are shown to be pure gauge terms allowing perturbation theory to again describe unitarity corrections and parton saturation effects. Genuine nonperturbative effects only come in at energies well beyond those energies where unitarity constraints first become important. (orig.)

Energy balance in MeV neutron induced fission

International Nuclear Information System (INIS)

Ruben, A.; Maerten, H.; Deeliger, D.

1992-01-01

In this paper, general trends of energy balance changes with increasing incidence energy are described in the framework of a simple scission point model including semi-empirical temperature-dependent shell correction energies. In particular, the different behavior of the total kinetic energy (TKE) dependence for several fissioning nuclei (Th, U, Pu) is explained

Measured energy dependence of L-shell photoelectric cross sections of lead in the energy region 17-50 keV

Energy Technology Data Exchange (ETDEWEB)

Arora, S K; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

1980-08-28

The energy dependence of L-shell photoelectric cross sections for lead in the energy region 17-50 keV has been investigated. The method utilises external conversion x-rays as the source of photons and it yields relative rather than absolute cross sections, but is simpler and more accurate. The results show fairly good agreement with theory.

Theoretical study of inner-shell ionization by heavy-particle impact

International Nuclear Information System (INIS)

Sarkadi, L.

2000-01-01

Complete text of publication follows. In our previous theoretical studies of inner-shell ionization of atoms by heavy-particle impact we applied the so-called coupled-states model. This theory was constructed to account for the intra-shell coupling effects in L-shell ionization. The model satisfactory reproduced the main tendencies of the measured L-shell ionization data (cross sections, L 3 -subshell alignment parameters) in a broad range of the collision energy, target and projectile atomic number. However, the accuracy of these calculations was uncertain, because the coupled-states model contained a series of approximation. The most questionable assumption was that the changes of the cross sections due to the subshell coupling effects were expressed by correction factors. The correction factors were derived considering only some representative transitions between the bound and continuum states, namely transitions into states of energy E f = 0 and angular momentum l f = 0.1. As a first step to improve the coupled-states model, a computer program was developed to calculate the matrix elements of the Coulomb interaction between a charged particle and an atomic electron, ∫ ψ* f (r) /R - r/ -1 ψ i (r)dr, for arbitrary final state energy E f and angular momentum l f . The ψ k (r)'s are non-relativistic hydrogenic wave functions. The program consists of subroutines that compute matrix elements between eigenstates of both the total angular momentum j, and the orbital angular momentum l. As further output quantities, the radial components of the multipole series expansion of the matrix elements (the so-called G functions) can be obtained, as well. The structure of the program is such that the hydrogenic wave functions can be replaced by arbitrary one-electron wave functions. The program was tested in calculations of K-, L- and M-shell ionization probabilities and cross sections within the framework of the straight-line version of the (first-order) semiclassical

Exploitation of jet properties for energy scale corrections for the CMS calorimeters

International Nuclear Information System (INIS)

Kirschenmann, Henning

2011-02-01

Jets form important event signatures in proton-proton collisions at the Large Hadron Collider (LHC) and the precise measurement of their energy is a crucial premise for a manifold of physics studies. Jets, which are reconstructed exclusively from calorimeter information, have been widely used within the CMS collaboration. However, the response of the calorimeters to incident particles depends heavily on their energy. In addition, it has been observed at previous experiments that the charged particle multiplicity and the radial distribution of constituents differ for jets induced by light quarks or by gluons. In conjunction with the non-linearity of the CMS calorimeters, this contributes to a mean energy response deviating from unity for calorimeter jets, depending on the jet-flavour. This thesis describes a jet-energy correction to be applied in addition to the default corrections within the CMS collaboration. This correction aims at decreasing the flavour dependence of the jet-energy response and improving the energy resolution. As many different effects contribute to the observed jet-energy response, a set of observables are introduced and corrections based on these observables are tested with respect to the above aims. A jet-width variable, which is defined from energy measured in the calorimeter, shows the best performance: A correction based on this observable improves the energy resolution by up to 20% at high transverse momenta in the central detector region and decreases the flavour dependence of the jet-energy response by a factor of two. A parametrisation of the correction is both derived from and validated on simulated data. First results from experimental data, to which the correction has been applied, are presented. The proposed jet-width correction shows a promising level of performance. (orig.)

Exploitation of jet properties for energy scale corrections for the CMS calorimeters

Energy Technology Data Exchange (ETDEWEB)

Kirschenmann, Henning

2011-02-15

Jets form important event signatures in proton-proton collisions at the Large Hadron Collider (LHC) and the precise measurement of their energy is a crucial premise for a manifold of physics studies. Jets, which are reconstructed exclusively from calorimeter information, have been widely used within the CMS collaboration. However, the response of the calorimeters to incident particles depends heavily on their energy. In addition, it has been observed at previous experiments that the charged particle multiplicity and the radial distribution of constituents differ for jets induced by light quarks or by gluons. In conjunction with the non-linearity of the CMS calorimeters, this contributes to a mean energy response deviating from unity for calorimeter jets, depending on the jet-flavour. This thesis describes a jet-energy correction to be applied in addition to the default corrections within the CMS collaboration. This correction aims at decreasing the flavour dependence of the jet-energy response and improving the energy resolution. As many different effects contribute to the observed jet-energy response, a set of observables are introduced and corrections based on these observables are tested with respect to the above aims. A jet-width variable, which is defined from energy measured in the calorimeter, shows the best performance: A correction based on this observable improves the energy resolution by up to 20% at high transverse momenta in the central detector region and decreases the flavour dependence of the jet-energy response by a factor of two. A parametrisation of the correction is both derived from and validated on simulated data. First results from experimental data, to which the correction has been applied, are presented. The proposed jet-width correction shows a promising level of performance. (orig.)

Occupation number dependence of molecular energy levels

International Nuclear Information System (INIS)

Giambiagi, M.S. de; Giambiagi, M.; Ferreira, R.

1977-08-01

The Roothaan expression for the energy of a closed-shell molecular system is generalized in order to apply to open shells. A continuous variation from 0 to 2 is supposed for each level's occupation number, extending to this range tbe correction due to the spurious repulsion appearing in the half-electron method. The characteristic equations of the Xα method are applied to the energy expressions. The one level case is discussed in detail. Ionic and excited states of the 1,3 transbutadiene π system are analyzed

Metabolic Energy Demand Is Not Increased during Initial Shell Formation of Bivalves Exposed to Aragonite Undersaturation

Science.gov (United States)

Pan, F.; Frieder, C.; Applebaum, S.; Manahan, D. T.

2016-02-01

The Pacific oyster, Crassostrea gigas, is a major commercial species in global aquaculture. Ocean acidification is having a negative effect on larval production of this species, so the mechanisms of this impact are of considerable interest. Formation of new shell in C. gigas during the first 2-days post-fertilization results in a rapid six-fold increase in total mass. This period of early development has high sensitivity to changes in carbonate chemistry, in particular aragonite saturation state (Ω). An elevated energy cost for calcification at low Ω is often invoked as a mechanism. In this study, we characterized the developmental progression of first shell formation, total metabolic expenditure, and underlying biochemical processes of energy allocation during early development of C. gigas, under control (Ω >> 1) and undersaturated conditions (Ω pump activity (Na+, K+-ATPase) between the two treatments. We conclude that early development to the shelled-veliger larval stage does not require more energy at undersaturation. This finding helps constrain potential mechanisms of larval sensitivity to ocean acidification and narrows the focus for possible mitigation strategies for oyster aquaculture production.

Logarithmic corrections to gravitational entropy and the null energy condition

Energy Technology Data Exchange (ETDEWEB)

Parikh, Maulik, E-mail: maulik.parikh@asu.edu; Svesko, Andrew

2016-10-10

Using a relation between the thermodynamics of local horizons and the null energy condition, we consider the effects of quantum corrections to the gravitational entropy. In particular, we find that the geometric form of the null energy condition is not affected by the inclusion of logarithmic corrections to the Bekenstein–Hawking entropy.

Faraday Wave Turbulence on a Spherical Liquid Shell

Science.gov (United States)

Holt, R. Glynn; Trinh, Eugene H.

1996-01-01

Millimeter-radius liquid shells are acoustically levitated in an ultrasonic field. Capillary waves are observed on the shells. At low energies (minimal acoustic amplitude, thick shell) a resonance is observed between the symmetric and antisymmetric thin film oscillation modes. At high energies (high acoustic pressure, thin shell) the shell becomes fully covered with high-amplitude waves. Temporal spectra of scattered light from the shell in this regime exhibit a power-law decay indicative of turbulence.

Stability of bubble nuclei through Shell-Effects

OpenAIRE

Dietrich, Klaus; Pomorski, Krzysztof

1997-01-01

We investigate the shell structure of bubble nuclei in simple phenomenological shell models and study their binding energy as a function of the radii and of the number of neutron and protons using Strutinsky's method. Shell effects come about, on the one hand, by the high degeneracy of levels with large angular momentum and, on the other, by the big energy gaps between states with a different number of radial nodes. Shell energies down to -40 MeV are shown to occur for certain magic nuclei. E...

Highly stable supercapacitors with conducting polymer core-shell electrodes for energy storage applications

KAUST Repository

Xia, Chuan; Chen, Wei; Wang, Xianbin; Hedhili, Mohamed N.; Wei, Nini; Alshareef, Husam N.

2015-01-01

commercial application. Here, the development of nanostructured PAni-RuO2 core-shell arrays as electrodes for highly stable pseudocapacitors with excellent energy storage performance is reported. A thin layer of RuO2 grown by atomic layer deposition (ALD

Helping people build a better world? Barriers to more environmentally friendly energy production in China: the case of Shell

Energy Technology Data Exchange (ETDEWEB)

Buan, Inga Fritzen

2008-03-15

China's rapid industrialization and economic expansion are causing massive environmental damage, with consequences beyond the country's borders, especially due to the use of fossil fuels' effect on climate change. Shell China can contribute to making energy production, if not clean and sustainable, then cleaner and more sustainable by making existing energy production more environmentally friendly; by diversifying and developing alternative energy sources; and by creating precedence influencing others to follow in its footsteps. The first goal of this report is to identify and analyze changes that have happened in the Shell Group since the 1990s when energy companies started their 'greening' processes. These changed happened due to stricter environmental legislation, increased civil society pressure and media scrutiny. Changes on the global and headquarters level in a company do not, however, necessitate similar developments in its national and local level operations. The second goal is thus to analyze to which degree the changes in the Shell Group have had relevance for Shell China and whether barriers in the Chinese context influence its prospects to operate in a more environmentally friendly way. (author). 64 refs

Dispersion- and Exchange-Corrected Density Functional Theory for Sodium Ion Hydration.

Science.gov (United States)

Soniat, Marielle; Rogers, David M; Rempe, Susan B

2015-07-14

A challenge in density functional theory is developing functionals that simultaneously describe intermolecular electron correlation and electron delocalization. Recent exchange-correlation functionals address those two issues by adding corrections important at long ranges: an atom-centered pairwise dispersion term to account for correlation and a modified long-range component of the electron exchange term to correct for delocalization. Here we investigate how those corrections influence the accuracy of binding free energy predictions for sodium-water clusters. We find that the dual-corrected ωB97X-D functional gives cluster binding energies closest to high-level ab initio methods (CCSD(T)). Binding energy decomposition shows that the ωB97X-D functional predicts the smallest ion-water (pairwise) interaction energy and larger multibody contributions for a four-water cluster than most other functionals - a trend consistent with CCSD(T) results. Also, ωB97X-D produces the smallest amounts of charge transfer and the least polarizable waters of the density functionals studied, which mimics the lower polarizability of CCSD. When compared with experimental binding free energies, however, the exchange-corrected CAM-B3LYP functional performs best (error <1 kcal/mol), possibly because of its parametrization to experimental formation enthalpies. For clusters containing more than four waters, "split-shell" coordination must be considered to obtain accurate free energies in comparison with experiment.

Local functional derivative of the total energy and the shell structure in atoms and molecules

NARCIS (Netherlands)

Pino, R.; Markvoort, Albert. J.; Santen, van R.A.; Hilbers, P.A.J.

2003-01-01

The full and local Thomas–Fermi–Dirac energy functional derivatives are evaluated at Hartree–Fock densities for several atoms and molecules. These functions are interpreted as local chemical potentials and related mainly to kinetic energy functional derivatives. They are able to reveal the shell

Logarithmic corrections to gravitational entropy and the null energy condition

Directory of Open Access Journals (Sweden)

Maulik Parikh

2016-10-01

Full Text Available Using a relation between the thermodynamics of local horizons and the null energy condition, we consider the effects of quantum corrections to the gravitational entropy. In particular, we find that the geometric form of the null energy condition is not affected by the inclusion of logarithmic corrections to the Bekenstein–Hawking entropy.

Thick-target method in the measurement of inner-shell ionization cross-sections by low-energy electron impact

International Nuclear Information System (INIS)

An, Z.; Wu, Y.; Liu, M.T.; Duan, Y.M.; Tang, C.H.

2006-01-01

In this paper, we have studied the thick-target method for the measurements of atomic inner-shell ionization cross-section or X-ray production cross-section by keV electron impact. We find that in the processes of electron impact on the thick targets, the ratios of the characteristic X-ray yields of photoelectric ionization by bremsstrahlung to the total characteristic X-ray yields are Z-dependent and shell-dependent, and the ratios also show the weak energy-dependence. In addition, in the lower incident energy region (i.e. U < 5-6), the contribution from the rediffusion effect and the secondary electrons can be negligible. In general, the thick-target method can be appropriately applied to the measurements of atomic inner-shell ionization cross-sections or X-ray production cross-sections by electron impact for low and medium Z elements in the lower incident electron energy (i.e. U < 5-6). The experimental accuracies by the thick-target method can reach to the level equivalent or superior to the accuracies of experimental data based on the thin-target method. This thick-target method has been applied to the measurement of K-shell ionization cross-sections of Ni element by electron impact in this paper

Pade approximants for the ground-state energy of closed-shell quantum dots

International Nuclear Information System (INIS)

Gonzalez, A.; Partoens, B.; Peeters, F.M.

1997-08-01

Analytic approximations to the ground-state energy of closed-shell quantum dots (number of electrons from 2 to 210) are presented in the form of two-point Pade approximants. These Pade approximants are constructed from the small- and large-density limits of the energy. We estimated that the maximum error, reached for intermediate densities, is less than ≤ 3%. Within that present approximation the ground-state is found to be unpolarized. (author). 21 refs, 3 figs, 2 tabs

Short-range second order screened exchange correction to RPA correlation energies

Science.gov (United States)

Beuerle, Matthias; Ochsenfeld, Christian

2017-11-01

Direct random phase approximation (RPA) correlation energies have become increasingly popular as a post-Kohn-Sham correction, due to significant improvements over DFT calculations for properties such as long-range dispersion effects, which are problematic in conventional density functional theory. On the other hand, RPA still has various weaknesses, such as unsatisfactory results for non-isogyric processes. This can in parts be attributed to the self-correlation present in RPA correlation energies, leading to significant self-interaction errors. Therefore a variety of schemes have been devised to include exchange in the calculation of RPA correlation energies in order to correct this shortcoming. One of the most popular RPA plus exchange schemes is the second order screened exchange (SOSEX) correction. RPA + SOSEX delivers more accurate absolute correlation energies and also improves upon RPA for non-isogyric processes. On the other hand, RPA + SOSEX barrier heights are worse than those obtained from plain RPA calculations. To combine the benefits of RPA correlation energies and the SOSEX correction, we introduce a short-range RPA + SOSEX correction. Proof of concept calculations and benchmarks showing the advantages of our method are presented.

Yolk-shell structured Sb@C anodes for high energy Na-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Song, Junhua; Yan, Pengfei; Luo, Langli; Qi, Xingguo; Rong, Xiaohui; Zheng, Jianming; Xiao, Biwei; Feng, Shuo; Wang, Chongmin; Hu, Yong-Sheng; Lin, Yuehe; Sprenkle, Vincent L.; Li, Xiaolin

2017-10-01

Despite great advances in sodium-ion battery developments, the search for high energy and stable anode materials remains a challenge. Alloy or conversion-typed anode materials are attractive candidates of high specific capacity and low voltage potential, yet their applications are hampered by the large volume expansion and hence poor electrochemical reversibility and fast capacity fade. Here, we use antimony (Sb) as an example to demonstrate the use of yolk-shell structured anodes for high energy Na-ion batteries. The Sb@C yolk-shell structure prepared by controlled reduction and selective removal of Sb2O3 from carbon coated Sb2O3 nanoparticles can accommodate the Sb swelling upon sodiation and improve the structural/electrical integrity against pulverization. It delivers a high specific capacity of ~554 mAh•g-1, good rate capability (315 mhA•g-1 at 10C rate) and long cyclability (92% capacity retention over 200 cycles). Full-cells of O3-Na0.9[Cu0.22Fe0.30Mn0.48]O2 cathodes and Sb@C-hard carbon composite anodes demonstrate a high specific energy of ~130 Wh•kg-1 (based on the total mass of cathode and anode) in the voltage range of 2.0-4.0 V, ~1.5 times energy of full-cells with similar design using hard carbon anodes.

Energy spectra in $p$-shell $\\Lambda$ hypernuclei and $^{19}_{\\Lambda}\\textrm{F}$ and spin-dependent $\\Lambda N$ interactions

OpenAIRE

Kanada-En'yo, Yoshiko; Isaka, Masahiro; Motoba, Toshio

2018-01-01

Energy spectra of $0s$-orbit $\\Lambda$ states in $p$-shell $\\Lambda$ hypernuclei ($^{A}_\\Lambda Z$) and those in $^{19}_{\\Lambda}\\textrm{F}$ are studied with the microscopic cluster model and antisymmetrized molecular dynamics using the $G$-matrix effective $\\Lambda N$ ($\\Lambda NG$) interactions. Spin-dependent terms of the ESC08a version of the $\\Lambda NG$ interactions are tested and phenomenologically tuned to reproduce observed energy spectra in $p$-shell $^{A}_\\Lambda Z$. Spin-dependent...

Feasibility study of thermal processing of cacao shells with energy utilization. Haalbaarheidsstudie thermische verwerking cacaodop met energiebenutting

Energy Technology Data Exchange (ETDEWEB)

De Vries, R; Pfeiffer, A E [KEMA Milieu Technologie, Arnhem (Netherlands)

1994-05-27

A cacao factory in Zaanstad, Netherlands, produces cacao shells, which are applied as filling material in fodder. However, while the development of the market and environmental regulations are uncertain, the option to use cacao shells as an energy source to generate heat and/or electricity seems to be attractive. Attention is paid to the consequences of the combustion of cacao shells for which two variants are considered: (1) only heat production which covers the total heat demand; (2) combined generation of power and heat, which saves natural gas and electricity. Surplus power can be supplied to the grid. Descriptions of the systems for the two variants are given, as well as the costs and benefits. A preference for one of the two variants depends on the market sales for cacao shells. If it is decided to put the chosen installation to tender it is recommended to investigate further the subsidy options and the possibility of cooperation with the energy utility sector. In the appendix the results of the flue gas purification concept are presented. 5 figs., 6 tabs., 1 appendix

Energy efficiency of error correction on wireless systems

NARCIS (Netherlands)

Havinga, Paul J.M.

1999-01-01

Since high error rates are inevitable to the wireless environment, energy-efficient error-control is an important issue for mobile computing systems. We have studied the energy efficiency of two different error correction mechanisms and have measured the efficiency of an implementation in software.

Saturation and Energy Corrections for TeV Electrons and Photons

CERN Document Server

Clerbaux, Barbara; Mahmoud, Tariq; Marage, Pierre Edouard

2006-01-01

This note presents a study of the response of the CMS electromagnetic calorimeter ECAL to high energy electrons and photons (from 500 to 4000 GeV), using the full simulation of the CMS detector. The longitudinal containment and the lateral extension of high energy showers are discussed, and energy and eta dependent correction factors F(E_meas, eta), where E_meas = E_ECAL + E_HCAL, are determined in order to reconstruct the incident particle energy, using the energies measured in the ECAL and in the hadronic calorimeter HCAL. For ECAL barrel crystals with energy deposit higher than 1700 GeV, improvements are proposed to techniques aimed at correcting for the effects of electronics saturation.

Interacting holographic dark energy with logarithmic correction

OpenAIRE

Jamil, Mubasher; Farooq, M. Umar

2010-01-01

The holographic dark energy (HDE) is considered to be the most promising candidate of dark energy. Its definition is originally motivated from the entropy-area relation which depends on the theory of gravity under consideration. Recently a new definition of HDE is proposed with the help of quantum corrections to the entropy-area relation in the setup of loop quantum cosmology. Using this new definition, we investigate the model of interacting dark energy and derive its effective equation of s...

Inflation via logarithmic entropy-corrected holographic dark energy model

Energy Technology Data Exchange (ETDEWEB)

Darabi, F.; Felegary, F. [Azarbaijan Shahid Madani University, Department of Physics, Tabriz (Iran, Islamic Republic of); Setare, M.R. [University of Kurdistan, Department of Science, Bijar (Iran, Islamic Republic of)

2016-12-15

We study the inflation in terms of the logarithmic entropy-corrected holographic dark energy (LECHDE) model with future event horizon, particle horizon, and Hubble horizon cut-offs, and we compare the results with those obtained in the study of inflation by the holographic dark energy HDE model. In comparison, the spectrum of primordial scalar power spectrum in the LECHDE model becomes redder than the spectrum in the HDE model. Moreover, the consistency with the observational data in the LECHDE model of inflation constrains the reheating temperature and Hubble parameter by one parameter of holographic dark energy and two new parameters of logarithmic corrections. (orig.)

Inflation via logarithmic entropy-corrected holographic dark energy model

International Nuclear Information System (INIS)

Darabi, F.; Felegary, F.; Setare, M.R.

2016-01-01

We study the inflation in terms of the logarithmic entropy-corrected holographic dark energy (LECHDE) model with future event horizon, particle horizon, and Hubble horizon cut-offs, and we compare the results with those obtained in the study of inflation by the holographic dark energy HDE model. In comparison, the spectrum of primordial scalar power spectrum in the LECHDE model becomes redder than the spectrum in the HDE model. Moreover, the consistency with the observational data in the LECHDE model of inflation constrains the reheating temperature and Hubble parameter by one parameter of holographic dark energy and two new parameters of logarithmic corrections. (orig.)

Highly stable supercapacitors with conducting polymer core-shell electrodes for energy storage applications

KAUST Repository

Xia, Chuan

2015-01-14

Conducting polymers such as polyaniline (PAni) show a great potential as pseudocapacitor materials for electrochemical energy storage applications. Yet, the cycling instability of PAni resulting from structural alteration is a major hurdle to its commercial application. Here, the development of nanostructured PAni-RuO2 core-shell arrays as electrodes for highly stable pseudocapacitors with excellent energy storage performance is reported. A thin layer of RuO2 grown by atomic layer deposition (ALD) on PAni nanofibers plays a crucial role in stabilizing the PAni pseudocapacitors and improving their energy density. The pseudocapacitors, which are based on optimized PAni-RuO2 core-shell nanostructured electrodes, exhibit very high specific capacitance (710 F g-1 at 5 mV s-1) and power density (42.2 kW kg-1) at an energy density of 10 Wh kg-1. Furthermore, they exhibit remarkable capacitance retention of ≈88% after 10 000 cycles at very high current density of 20 A g-1, superior to that of pristine PAni-based pseudocapacitors. This prominently enhanced electrochemical stability successfully demonstrates the buffering effect of ALD coating on PAni, which provides a new approach for the preparation of metal-oxide/conducting polymer hybrid electrodes with excellent electrochemical performance.

A refined element-based Lagrangian shell element for geometrically nonlinear analysis of shell structures

Directory of Open Access Journals (Sweden)

Woo-Young Jung

2015-04-01

Full Text Available For the solution of geometrically nonlinear analysis of plates and shells, the formulation of a nonlinear nine-node refined first-order shear deformable element-based Lagrangian shell element is presented. Natural co-ordinate-based higher order transverse shear strains are used in present shell element. Using the assumed natural strain method with proper interpolation functions, the present shell element generates neither membrane nor shear locking behavior even when full integration is used in the formulation. Furthermore, a refined first-order shear deformation theory for thin and thick shells, which results in parabolic through-thickness distribution of the transverse shear strains from the formulation based on the third-order shear deformation theory, is proposed. This formulation eliminates the need for shear correction factors in the first-order theory. To avoid difficulties resulting from large increments of the rotations, a scheme of attached reference system is used for the expression of rotations of shell normal. Numerical examples demonstrate that the present element behaves reasonably satisfactorily either for the linear or for geometrically nonlinear analysis of thin and thick plates and shells with large displacement but small strain. Especially, the nonlinear results of slit annular plates with various loads provided the benchmark to test the accuracy of related numerical solutions.

Mean excitation energy of polystyrene extracted from proton-stopping-power measurements

International Nuclear Information System (INIS)

Porter, L.E.

1980-01-01

The measured stopping power of polystyrene for 2.2- to 5.9-MeV protons has been analyzed with the Bloch projectile-z 4 correction term and a modified low-velocity projectile-z 3 term included in the Bethe-Bloch formula. When the full-strength Walske K-shell correction was utilized, the mean excitation energy corresponding to the best fit of the measurements was (71.1 +- 1.8) eV. This result was obtained for a value of the free parameter of the low-velocity projectile-z 3 effect formalism of 1.90 +- 0.05, whether or not a Walske L-shell correction was included

Scission-point model of nuclear fission based on deformed-shell effects

International Nuclear Information System (INIS)

Wilkins, B.D.; Steinberg, E.P.; Chasman, R.R.

1976-01-01

A static model of nuclear fission is proposed based on the assumption of statistical equilibrium among collective degrees of freedom at the scission point. The relative probabilities of formation of complementary fission fragment pairs are determined from the relative potential energies of a system of two nearly touching, coaxial spheroids with quadrupole deformations. The total potential energy of the system at the scission point is calculated as the sum of liquid-drop and shell- and pairing-correction terms for each spheroid, and Coulomb and nuclear potential terms describing the interaction between them. The fissioning system at the scission point is characterized by three parameters: the distance between the tips of the spheroids (d), the intrinsic excitation energy of the fragments (tau/sub int/), and a collective temperature (T/sub coll/). No attempt is made to adjust these parameters to give optimum fits to experimental data, but rather, a single choice of values for d, tau/sub int/, and T/sub coll/ is used in the calculations for all fissioning systems. The general trends of the distributions of mass, nuclear charge, and kinetic energy in the fission of a wide range of nuclides from Po to Fm are well reproduced in the calculations. The major influence of the deformed-shell corrections for neutrons is indicated and provides a convenient framework for the interpretation of observed trends in the data and for the prediction of new results. The scission-point configurations derived from the model provide an interpretation of the ''saw-tooth'' neutron emission curve as well as previously unexplained observations on the variation of TKE for isotopes of U, Pu, Cm, and Cf; structure in the width of total kinetic energy release as a function of fragment mass ratio; and a difference in threshold energies for symmetric and asymmetric mass splits in the fission of Ra and Ac isotopes

A study of the compartmentalization of core-shell nanoparticles through fluorescence energy transfer of dopants

Energy Technology Data Exchange (ETDEWEB)

Chavez, Jorge L; Jiang Hui; Duran, Randolph S, E-mail: rduran@lsu.edu [Department of Chemistry, University of Florida, PO Box 117200, Gainesville, FL 32611 (United States)

2010-02-05

Hybrid organic-inorganic templates and core-shell nanoparticles were used as models to study the communication between fluorescent probes placed inside nanoparticles. The hybrid templates were prepared on the basis of a mixed-surfactant system using octadecyltrimethoxysilane as a reactive amphiphile. The core-shell particles were obtained after coating of the templates with a siloxane shell, using the silanol groups on their surface. Atomic force microscopy imaging showed that the templates were made of a flexible material that flattened significantly after deposition on a substrate and evaporation of the solvent. Pyrene was sequestered by the templates in an aqueous suspension, which placed it in a nonpolar environment, as observed by its fluorescence response. Subsequently, double-doped templates were prepared by sequestering coumarin 153 (C153), with pyrene-doped hybrid templates. The communication between these probes was studied on the basis of their spectral properties, by means of fluorescence resonance energy transfer (FRET). Energy transfer between the dyes with efficiencies up to 55% was observed. Similarly, double-doped core-shell particles prepared on the basis of the hybrid templates were doped with this pair of dyes. Despite the presence of the shell, which was intended to increment the average separation between the probes, interaction of the dyes was observed, although with lower efficiencies. A similar study was performed with C153 and 4-(dicyanomethylene)-2-methyl-6-p-(dimethylamino)styryl-4H-pyran (DCM). FRET studies indicated that the probes were placed in proximity to each other. We confirmed these observations by means of fluorescence lifetime measurements, which showed a decrease in the lifetime of the donor upon addition of the acceptor.

Scenarios of the long term evolution of the energy sector. Energy needs, choices and possibilities: Shell's scenarios for 2050. The long-term evolution of the energy sector. A vision of the 2020-2050 energy mix. Phase dynamics analysis of energy demand scenarios

International Nuclear Information System (INIS)

Chevallier, B.; Appert, O; Bauquis, P.R.; Alba, P.

2002-01-01

This dossier comprises 4 articles dealing with energy scenarios. The first article presents the prospective studies carried out by the Shell group which lead to the construction of two scenarios entitled: 'dynamics as usual' and 'the spirit of the coming age'. Both scenarios foresee an explosion of the primary energy demand for the coming next 50 years (multiplied by a factor of 2 to 2.8 with respect to 2000) with a decline of hydrocarbons for the benefit of gas and renewable energies (including bio-fuels), while nuclear and coal will still represent a quarter of our needs. However, the main uncertainty remains the demographic expansion during the next 50 years. The second article presents the energy models and projections of the IEA for the long-term evolution of the energy sector (petroleum, gas, coal, renewable energy and uranium resources) and the main uncertainties of these projections (economic growth, environmental policies, technological evolutions). The third article presents the agreements and divergences of the author's forecasts for 2050 with Shell's scenarios, while the last article makes a comparison between the IEA, IIASA-CME and Shell scenarios using a phase dynamics analysis. (J.S.)

Power corrections in QCD: A matter of energy resolution

International Nuclear Information System (INIS)

Akhoury, R.; Zakharov, V.I.

1996-01-01

We consider powerlike corrections in QCD which can be viewed as power suppressed infrared singularities. We argue that the presence of these singularities depends crucially on the energy resolution. In the case of poor energy resolution, i.e., inclusive cross sections, there are constraints on infrared singularities expressed by the Kinoshita-Lee-Nauenberg (KLN) theorem. We rewrite the theorem in covariant notations and argue that the KLN theorem implies the extension of the Bloch-Nordsieck cancellation of logarithmic singularities to the case of linear corrections. copyright 1996 The American Physical Society

Unitary screening corrections in high energy hadron reactions

Energy Technology Data Exchange (ETDEWEB)

Maor, U

1994-10-01

The role of s-channel unitarity screening corrections, calculated in the eikonal approximation, is investigated for elastic and diffractive hadron-hadron and photon-hadron scattering in the energy limit. We examine the differences between our results and those obtained from the supercritical Pomeron-Reggeon model with no such corrections. It is argued that the saturation of cross sections is attained at different scales for different channels. In particular, we point out that whereas the saturation scale for elastic scattering apparently above the Tevatron energy range, the appropriate diffraction scale is considerably lower and can be assessed with presently available data. A review of the relevant data and its implications is presented. (author). 12 refs, 3 figs, 2 tabs.

Off-shell distortions of multichannel atomic processes

Science.gov (United States)

Barrachina, R. O.; Clauser, C. F.

2017-10-01

Any multichannel problem can be reduced to a succession of two-body events. However, these basic building blocks of many-body theories do not correspond to elastic processes but are off-the-energy-shell. In view of this difficulty, the great majority of the Distorted-Wave models includes a subsidiary approximation where these off-shell terms are arbitrarily forced to lie on the energy shell. At a first glance, since the energy deficiency is negligible for high enough velocities, the on-shell assumption seems to be completely justified. However, for the case of Coulomb interactions, the two-body off-shell distortions have branch-point singularities on the on-shell limit. In this article we demonstrate that these singularities might produce sizeable distortions of multiple scattering amplitudes, mainly when dealing with ion-ion collisions. Finally, we propose a method of including these distortions that might lead to better results that removing them completely.

Asymmetric-shell ignition capsule design to tune the low-mode asymmetry during the peak drive

International Nuclear Information System (INIS)

Gu, Jianfa; Dai, Zhensheng; Song, Peng; Zou, Shiyang; Ye, Wenhua; Zheng, Wudi; Gu, Peijun; Wang, Jianguo; Zhu, Shaoping

2016-01-01

The low-mode radiation flux asymmetry in the hohlraum is a main source of performance degradation in the National Ignition Facility (NIF) implosion experiments. To counteract the deleterious effects of the large positive P2 flux asymmetry during the peak drive, this paper develops a new tuning method called asymmetric-shell ignition capsule design which adopts the intentionally asymmetric CH ablator layer or deuterium-tritium (DT) ice layer. A series of two-dimensional implosion simulations have been performed, and the results show that the intentionally asymmetric DT ice layer can significantly improve the fuel ρR symmetry, hot spot shape, hot spot internal energy, and the final neutron yield compared to the spherical capsule. This indicates that the DT asymmetric-shell capsule design is an effective tuning method, while the CH ablator asymmetric-shell capsule could not correct the fuel ρR asymmetry, and it is not as effective as the DT asymmetric-shell capsule design.

Asymmetric-shell ignition capsule design to tune the low-mode asymmetry during the peak drive

Science.gov (United States)

Gu, Jianfa; Dai, Zhensheng; Song, Peng; Zou, Shiyang; Ye, Wenhua; Zheng, Wudi; Gu, Peijun; Wang, Jianguo; Zhu, Shaoping

2016-08-01

The low-mode radiation flux asymmetry in the hohlraum is a main source of performance degradation in the National Ignition Facility (NIF) implosion experiments. To counteract the deleterious effects of the large positive P2 flux asymmetry during the peak drive, this paper develops a new tuning method called asymmetric-shell ignition capsule design which adopts the intentionally asymmetric CH ablator layer or deuterium-tritium (DT) ice layer. A series of two-dimensional implosion simulations have been performed, and the results show that the intentionally asymmetric DT ice layer can significantly improve the fuel ρR symmetry, hot spot shape, hot spot internal energy, and the final neutron yield compared to the spherical capsule. This indicates that the DT asymmetric-shell capsule design is an effective tuning method, while the CH ablator asymmetric-shell capsule could not correct the fuel ρR asymmetry, and it is not as effective as the DT asymmetric-shell capsule design.

Asymmetric-shell ignition capsule design to tune the low-mode asymmetry during the peak drive

Energy Technology Data Exchange (ETDEWEB)

Gu, Jianfa, E-mail: gu-jianfa@iapcm.ac.cn; Dai, Zhensheng, E-mail: dai-zhensheng@iapcm.ac.cn; Song, Peng; Zou, Shiyang; Ye, Wenhua; Zheng, Wudi; Gu, Peijun; Wang, Jianguo; Zhu, Shaoping [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

2016-08-15

The low-mode radiation flux asymmetry in the hohlraum is a main source of performance degradation in the National Ignition Facility (NIF) implosion experiments. To counteract the deleterious effects of the large positive P2 flux asymmetry during the peak drive, this paper develops a new tuning method called asymmetric-shell ignition capsule design which adopts the intentionally asymmetric CH ablator layer or deuterium-tritium (DT) ice layer. A series of two-dimensional implosion simulations have been performed, and the results show that the intentionally asymmetric DT ice layer can significantly improve the fuel ρR symmetry, hot spot shape, hot spot internal energy, and the final neutron yield compared to the spherical capsule. This indicates that the DT asymmetric-shell capsule design is an effective tuning method, while the CH ablator asymmetric-shell capsule could not correct the fuel ρR asymmetry, and it is not as effective as the DT asymmetric-shell capsule design.

77 FR 10997 - Energy Conservation Program: Energy Conservation Standards for Distribution Transformers; Correction

Science.gov (United States)

2012-02-24

... Conservation Program: Energy Conservation Standards for Distribution Transformers; Correction AGENCY: Office of... standards for distribution transformers. It was recently discovered that values in certain tables of the...,'' including distribution transformers. The Energy Policy Act of 1992 (EPACT 1992), Public Law 102-486, amended...

Substantial enhancement of energy storage capability in polymer nanocomposites by encapsulation of BaTiO3 NWs with variable shell thickness.

Science.gov (United States)

Wang, Guanyao; Huang, Yanhui; Wang, Yuxin; Jiang, Pingkai; Huang, Xingyi

2017-08-09

Dielectric polymer nanocomposites have received keen interest due to their potential application in energy storage. Nevertheless, the large contrast in dielectric constant between the polymer and nanofillers usually results in a significant decrease of breakdown strength of the nanocomposites, which is unfavorable for enhancing energy storage capability. Herein, BaTiO 3 nanowires (NWs) encapsulated by TiO 2 shells of variable thickness were utilized to fabricate dielectric polymer nanocomposites. Compared with nanocomposites with bare BaTiO 3 NWs, significantly enhanced energy storage capability was achieved for nanocomposites with TiO 2 encapsulated BaTiO 3 NWs. For instance, an ultrahigh energy density of 9.53 J cm -3 at 440 MV m -1 could be obtained for nanocomposites comprising core-shell structured nanowires, much higher than that of nanocomposites with 5 wt% raw ones (5.60 J cm -3 at 360 MV m -1 ). The discharged energy density of the proposed nanocomposites with 5 wt% mTiO 2 @BaTiO 3 -1 NWs at 440 MV m -1 seems to rival or exceed those of some previously reported nanocomposites (mostly comprising core-shell structured nanofillers). More notably, this study revealed that the energy storage capability of the nanocomposites can be tailored by the TiO 2 shell thickness. Finite element simulations were employed to analyze the electric field distribution in the nanocomposites. The enhanced energy storage capability should be mainly attributed to the smoother gradient of dielectric constant between the nanofillers and polymer matrix, which alleviated the electric field concentration and leakage current in the polymer matrix. The methods and results herein offer a feasible approach to construct high-energy-density polymer nanocomposites with core-shell structured nanowires.

Generation of L sub-shell photo-ionization cross-sections for elements 18Z92 at energies .320-115.606 keV (A computer program 'LSPICS')

International Nuclear Information System (INIS)

Sharma, Ajay; Mittal, Raj

2005-01-01

L sub-shell photo-ionization cross-sections, σ Li , for elements 18Z92 at energies .320-115.606 keV have been generated from an empirical relation fitted to Scofield's L sub-shell photo-ionization cross-section values. The excitation energy E for an element is constrained by the condition that only L and higher shell vacancies are produced in the elements. The closeness of generated and existing values of Scofield's L sub-shell data recommends the use of generated values in the fields of atomic and molecular physics and for trace elemental analysis. For this purpose computer software 'LSPICS' has been developed. On personal computer LSPICS generates L sub-shell photo-ionization cross-section values in barns just by entering the atomic number of element and excitation photon energy in keV

Core-shell nanophosphor architecture: toward efficient energy transport in inorganic/organic hybrid solar cells.

Science.gov (United States)

Li, Qinghua; Yuan, Yongbiao; Chen, Zihan; Jin, Xiao; Wei, Tai-huei; Li, Yue; Qin, Yuancheng; Sun, Weifu

2014-08-13

In this work, a core-shell nanostructure of samarium phosphates encapsulated into a Eu(3+)-doped silica shell has been successfully fabricated, which has been confirmed by X-ray diffraction, transmission electron microscopy (TEM), and high-resolution TEM. Moreover, we report the energy transfer process from the Sm(3+) to emitters Eu(3+) that widens the light absorption range of the hybrid solar cells (HSCs) and the strong enhancement of the electron-transport of TiO2/poly(3-hexylthiophene) (P3HT) bulk heterojunction (BHJ) HSCs by introducing the unique core-shell nanoarchitecture. Furthermore, by applying femtosecond transient absorption spectroscopy, we successfully obtain the electron transport lifetimes of BHJ systems with or without incorporating the core-shell nanophosphors (NPs). Concrete evidence has been provided that the doping of core-shell NPs improves the efficiency of electron transfers from donor to acceptor, but the hole transport almost remains unchanged. In particular, the hot electron transfer lifetime was shortened from 30.2 to 16.7 ps, i.e., more than 44% faster than pure TiO2 acceptor. Consequently, a notable power conversion efficiency of 3.30% for SmPO4@Eu(3+):SiO2 blended TiO2/P3HT HSCs is achieved at 5 wt % as compared to 1.98% of pure TiO2/P3HT HSCs. This work indicates that the core-shell NPs can efficiently broaden the absorption region, facilitate electron-transport of BHJ, and enhance photovoltaic performance of inorganic/organic HSCs.

Higher order corrections to energy levels of muonic atoms

International Nuclear Information System (INIS)

Rinker, G.A. Jr.; Steffen, R.M.

1975-08-01

In order to facilitate the analysis of muonic x-ray spectra, the results of numerical computations of all higher order quantum electrodynamical corrections to the energy levels of muonic atoms are presented in tabular and graphical form. These corrections include the vacuum polarization corrections caused by emission and reabsorption of virtual electron pairs to all orders, including ''double-bubble'' and ''cracked-egg'' diagrams. An estimate of the Delbruecke scattering-type correction is presented. The Lamb-shift (second- and fourth-order vertex) corrections have been calculated including the correction for the anomalous magnetic moment of the muon. The relativistic nuclear motion (or recoil) correction as well as the correction caused by the screening of the atomic electrons is presented in graphs. For the sake of completeness a graph of the nuclear polarization as computed on the basis of Chen's approach has been included. All calculations were made with a two-parameter Fermi distribution of the nuclear charge density. 7 figures, 23 references

Alternative reproductive tactics in snail shell-brooding cichlids diverge in energy reserve allocation.

Science.gov (United States)

von Kuerthy, Corinna; Tschirren, Linda; Taborsky, Michael

2015-05-01

Life history theory predicts that the amount of resources allocated to reproduction should maximize an individual's lifetime reproductive success. So far, resource allocation in reproduction has been studied mainly in females. Intraspecific variation of endogenous energy storage and utilization patterns of males has received little attention, although these patterns may vary greatly between individuals pursuing alternative reproductive tactics (ARTs). ARTs are characterized by systematic variation of behavioral, physiological, and often morphological traits among same-sex conspecifics. Some individuals may rely on previously accumulated reserves, because of limited foraging opportunities during reproduction. Others may be able to continue foraging during reproduction, thus relying on reserves to a lesser extent. We therefore predicted that, if male tactics involve such divergent limitations and trade-offs within a species, ARTs should correspondingly differ in energy reserve allocation and utilization. To test this prediction, we studied short-term and long-term reserve storage patterns of males in the shell-brooding cichlid Lamprologus callipterus. In this species, bourgeois males investing in territory defense, courtship, and guarding of broods coexist with two distinct parasitic male tactics: (1) opportunistic sneaker males attempting to fertilize eggs by releasing sperm into the shell opening when a female is spawning; and (2) specialized dwarf males attempting to enter the shell past the spawning female to fertilize eggs from inside the shell. Sneaker males differed from other male types by showing the highest amount of accumulated short-term and long-term fat stores, apparently anticipating their upcoming adoption of the nest male status. In contrast, nest males depleted previously accumulated energy reserves with increasing nest holding period, as they invest heavily into costly reproductive behaviors while not taking up any food. This conforms to a capital

Comparisons between shell-model calculations, seniority truncation, and quasiparticle approximations: Application to the odd Ni isotopes and odd N = 82 isotones

International Nuclear Information System (INIS)

Losano, L.; Dias, H.; Krmpotic, F.; Wildenthal, B.H.

1988-01-01

A detailed study of the results of correcting BCS approximation for the effects of particle-number projection and blocking has been carried out. A low-seniority shell-model approximation was used as the frame of reference for investigating the mixing of one- and three-quasiparticle states in odd-mass Ni isotopes and in odd-mass N = 82 isotones. We discuss the results obtained for the energy spectra and electromagnetic decay properties. Effects of seniority-five configurations on the low-lying states have also been studied through the comparison of the low-seniority shell-model results with those which arose from the corresponding full shell-model calculations

Au@NaYF{sub 4}:Tb{sup 3+} core@shell nanostructures: Synthesis and construction of luminescence resonance energy transfer

Energy Technology Data Exchange (ETDEWEB)

Song, Yan; Liu, Guixia, E-mail: liuguixia22@163.com; Dong, Xiangting; Wang, Jinxian; Yu, Wensheng

2016-03-15

Luminescence resonance energy transfer (LRET) system can be constructed using NaYF{sub 4}:Tb{sup 3+} luminescence nanocrystals and gold nanoparticles (AuNPs) served as energy donor and acceptor, respectively. The AuNPs modified by cetyltrimethylammonium bromide (CTAB) were synthesized first and NaYF{sub 4}:Tb{sup 3+} shells encapsulated Au cores via a hydrothermal method. The synthesized materials were well characterized by X-ray diffraction (XRD), Fourier-transform infrared spectra (FT-IR), Transmission electron microscopy (TEM), X-ray photoelectron spectrum (XPS), UV–vis absorption spectra (UV–vis) and photoluminescence (PL) measurement. The results indicate that the synthesized Au@NaYF{sub 4}:Tb{sup 3+} core–shell nanoparticles have spherical morphology with a size of 80–90 nm and the shell layers of NaYF{sub 4}:Tb{sup 3+} nanocrystals have pure cubic structure. The luminescence properties of Au@NaYF{sub 4}:Tb{sup 3+} core–shell nanoparticles are same as those of NaYF{sub 4}:Tb{sup 3+} particles. The LRET process was realized using the core–shell nanoarchitectures due to the absorption spectrum of AuNPs matches well with the major emission peaks of Tb{sup 3+} ions. The LRET experiments have successfully verified the energy transfer between NaYF{sub 4}:Tb{sup 3+} nanocrystals and AuNPs. Additionally, the emission intensities of Tb{sup 3+} ions and the content of AuNPs exhibited a fair linear correlation.

Attenuation correction strategies for multi-energy photon emitters using SPECT

International Nuclear Information System (INIS)

Pretorius, P.H.; King, M.A.; Pan, T.S.

1996-01-01

The aim of this study was to investigate whether the photopeak window projections from different energy photons can be combined into a single window for reconstruction or if it is better to not combine the projections due to differences in the attenuation maps required for each photon energy. The mathematical cardiac torso (MCAT) phantom was modified to simulate the uptake of Ga-67 in the human body. Four spherical hot tumors were placed in locations which challenged attenuation correction. An analytical 3D projector with attenuation and detector response included was used to generate projection sets. Data were reconstructed using filtered backprojection (FBP) reconstruction with Butterworth filtering in conjunction with one iteration of Chang attenuation correction, and with 5 and 10 iterations of ordered-subset maximum-likelihood expectation-maximization reconstruction. To serve as a standard for comparison, the projection sets obtained from the two energies were first reconstructed separately using their own attenuation maps. The emission data obtained from both energies were added and reconstructed using the following attenuation strategies: (1) the 93 keV attenuation map for attenuation correction, (2) the 185 keV attenuation map for attenuation correction, (3) using a weighted mean obtained from combining the 93 keV and 185 keV maps, and (4) an ordered subset approach which combines both energies. The central count ratio (CCR) and total count ratio (TCR) were used to compare the performance of the different strategies. Compared to the standard method, results indicate an over-estimation with strategy 1, an under-estimation with strategy 2 and comparable results with strategies 3 and 4. In all strategies, the CCR's of sphere 4 were under-estimated, although TCR's were comparable to that of the other locations. The weighted mean and ordered subset strategies for attenuation correction were of comparable accuracy to reconstruction of the windows separately

Composition, Shell Strength, and Metabolizable Energy of Mulinia lateralis and Ischadium recurvum as Food for Wintering Surf Scoters (Melanitta perspicillata.

Directory of Open Access Journals (Sweden)

Alicia M Wells-Berlin

Full Text Available Decline in surf scoter (Melanitta perspicillata waterfowl populations wintering in the Chesapeake Bay has been associated with changes in the availability of benthic bivalves. The Bay has become more eutrophic, causing changes in the benthos available to surf scoters. The subsequent decline in oyster beds (Crassostrea virginica has reduced the hard substrate needed by the hooked mussel (Ischadium recurvum, one of the primary prey items for surf scoters, causing the surf scoter to switch to a more opportune species, the dwarf surfclam (Mulinia lateralis. The composition (macronutrients, minerals, and amino acids, shell strength (N, and metabolizable energy (kJ of these prey items were quantified to determine the relative foraging values for wintering scoters. Pooled samples of each prey item were analyzed to determine composition. Shell strength (N was measured using a shell crack compression test. Total collection digestibility trials were conducted on eight captive surf scoters. For the prey size range commonly consumed by surf scoters (6-12 mm for M. lateralis and 18-24 mm for I. recurvum, I. recurvum contained higher ash, protein, lipid, and energy per individual organism than M. lateralis. I. recurvum required significantly greater force to crack the shell relative to M. lateralis. No difference in metabolized energy was observed for these prey items in wintering surf scoters, despite I. recurvum's higher ash content and harder shell than M. lateralis. Therefore, wintering surf scoters were able to obtain the same amount of energy from each prey item, implying that they can sustain themselves if forced to switch prey.

Majorana states in prismatic core-shell nanowires

Science.gov (United States)

Manolescu, Andrei; Sitek, Anna; Osca, Javier; Serra, Llorenç; Gudmundsson, Vidar; Stanescu, Tudor Dan

2017-09-01

We consider core-shell nanowires with conductive shell and insulating core and with polygonal cross section. We investigate the implications of this geometry on Majorana states expected in the presence of proximity-induced superconductivity and an external magnetic field. A typical prismatic nanowire has a hexagonal profile, but square and triangular shapes can also be obtained. The low-energy states are localized at the corners of the cross section, i.e., along the prism edges, and are separated by a gap from higher energy states localized on the sides. The corner localization depends on the details of the shell geometry, i.e., thickness, diameter, and sharpness of the corners. We study systematically the low-energy spectrum of prismatic shells using numerical methods and derive the topological phase diagram as a function of magnetic field and chemical potential for triangular, square, and hexagonal geometries. A strong corner localization enhances the stability of Majorana modes to various perturbations, including the orbital effect of the magnetic field, whereas a weaker localization favorizes orbital effects and reduces the critical magnetic field. The prismatic geometry allows the Majorana zero-energy modes to be accompanied by low-energy states, which we call pseudo Majorana, and which converge to real Majoranas in the limit of small shell thickness. We include the Rashba spin-orbit coupling in a phenomenological manner, assuming a radial electric field across the shell.

Crosstalk corrections for improved energy resolution with highly segmented HPGe-detectors

International Nuclear Information System (INIS)

Bruyneel, Bart; Reiter, Peter; Wiens, Andreas; Eberth, Juergen; Hess, Herbert; Pascovici, Gheorghe; Warr, Nigel; Aydin, Sezgin; Bazzacco, Dino; Recchia, Francesco

2009-01-01

Crosstalk effects of 36-fold segmented, large volume AGATA HPGe detectors cause shifts in the γ-ray energy measured by the inner core and outer segments as function of segment multiplicity. The positions of the segment sum energy peaks vary approximately linearly with increasing segment multiplicity. The resolution of these peaks deteriorates also linearly as a function of segment multiplicity. Based on single event treatment, two methods were developed in the AGATA Collaboration to correct for the crosstalk induced effects by employing a linear transformation. The matrix elements are deduced from coincidence measurements of γ-rays of various energies as recorded with digital electronics. A very efficient way to determine the matrix elements is obtained by measuring the base line shifts of untriggered segments using γ-ray detection events in which energy is deposited in a single segment. A second approach is based on measuring segment energy values for γ-ray interaction events in which energy is deposited in only two segments. After performing crosstalk corrections, the investigated detector shows a good fit between the core energy and the segment sum energy at all multiplicities and an improved energy resolution of the segment sum energy peaks. The corrected core energy resolution equals the segment sum energy resolution which is superior at all folds compared to the individual uncorrected energy resolutions. This is achieved by combining the two independent energy measurements with the core contact on the one hand and the segment contacts on the other hand.

Fossil shell emission in dying radio loud AGNs

Science.gov (United States)

Kino, M.; Ito, H.; Kawakatu, N.; Orienti, M.; Nagai, H.; Wajima, K.; Itoh, R.

2016-02-01

We investigate shell emission associated with dying radio loud AGNs. First, based on our recent work by Ito et al. (2015), we describe the dynamical and spectral evolution of shells after stopping the jet energy injection. We find that the shell emission overwhelms that of the radio lobes soon after stopping the jet energy injection because fresh electrons are continuously supplied into the shell via the forward shock, while the radio lobes rapidly fade out without jet energy injection. We find that such fossil shells can be a new class of target sources for SKA telescope. Next, we apply the model to the nearby radio source 3C84. Then, we find that the fossil shell emission in 3C84 is less luminous in the radio band while it is bright in the TeV γ-ray band and can be detectable by CTA. Data from STELLA

Shell closure at the touching point of nuclear fragments

International Nuclear Information System (INIS)

Poenaru, D.N.; Greiner, W.; Gherghescu, R.A.

1998-01-01

Shell correction energy of the fission fragments remains practically unchanged when the separation distance increases from the sum of their radii up to infinity. The variation with mass asymmetry of the total deformation energy at the touching point configuration shows the valleys corresponding to different decay modes, which are produced when the two proton and/or the two neutron numbers are magic or almost magic. We present a contour plot of the deformation energy of the proton-rich α-emitter 106 Te, showing for the first time the α-decay valley. Different valleys mainly due to the doubly magic nuclei 100,132 Sn, 208 Pb, and other magic numbers, are illustrated by plotting the deformation energy at the touching point versus the proton number of the fragment, for the following parent nuclei: 106 Te; 116 Ce; 212 Po; 228 Th; 258 Fm, and 264 Fm. (author). Letter-to-the-editor

Critical Assessment of TD-DFT for Excited States of Open-Shell Systems: I. Doublet-Doublet Transitions.

Science.gov (United States)

Li, Zhendong; Liu, Wenjian

2016-01-12

A benchmark set of 11 small radicals is set up to assess the performance of time-dependent density functional theory (TD-DFT) for the excited states of open-shell systems. Both the unrestricted (U-TD-DFT) and spin-adapted (X-TD-DFT) formulations of TD-DFT are considered. For comparison, the well-established EOM-CCSD (equation-of-motion coupled-cluster with singles and doubles) is also used. In total, 111 low-lying singly excited doublet states are accessed by all the three approaches. Taking the MRCISD+Q (multireference configuration interaction with singles and doubles plus the Davidson correction) results as the benchmark, it is found that both U-TD-DFT and EOM-CCSD perform well for those states dominated by singlet-coupled single excitations (SCSE) from closed-shell to open-shell, open-shell to vacant-shell, or closed-shell to vacant-shell orbitals. However, for those states dominated by triplet-coupled single excitations (TCSE) from closed-shell to vacant-shell orbitals, both U-TD-DFT and EOM-CCSD fail miserably due to severe spin contaminations. In contrast, X-TD-DFT provides balanced descriptions of both SCSE and TCSE. As far as the functional dependence is concerned, it is found that, when the Hartree-Fock ground state does not suffer from the instability problem, both global hybrid (GH) and range-separated hybrid (RSH) functionals perform grossly better than pure density functionals, especially for Rydberg and charge-transfer excitations. However, if the Hartree-Fock ground state is instable or nearly instable, GH and RSH tend to underestimate severely the excitation energies. The SAOP (statistically averaging of model orbital potentials) performs more uniformly than any other density functionals, although it generally overestimates the excitation energies of valence excitations. Not surprisingly, both EOM-CCSD and adiabatic TD-DFT are incapable of describing excited states with substantial double excitation characters.

Meson exchange corrections in deep inelastic scattering on deuteron

International Nuclear Information System (INIS)

Kaptari, L.P.; Titov, A.I.

1989-01-01

Starting with the general equations of motion of the nucleons interacting with the mesons the one-particle Schroedinger-like equation for the nucleon wave function and the deep inelastic scattering amplitude with the meson-exchange currents are obtained. Effective pion-, sigma-, and omega-meson exchanges are considered. It is found that the mesonic corrections only partially (about 60%) restore the energy sum rule breaking because of the nucleon off-mass-shell effects in nuclei. This results contradicts with the prediction based on the calculation of the energy sum rule limited by the second order of the nucleon-meson vertex and static approximation. 17 refs.; 3 figs

Assessment of density functional theory for bonds formed between rare gases and open-shell atoms: a computational study of small molecules containing He, Ar, Kr and Xe.

Science.gov (United States)

Bertolus, Marjorie; Major, Mohamed; Brenner, Valérie

2012-01-14

The validity of the description of the DFT approximations currently implemented in plane wave DFT codes (LDA, GGA, meta-GGA, hybrid, GGA + empirical dispersion correction) for interactions between rare gases and open-shell atoms which form materials is poorly known. We have performed a first assessment of the accuracy of these functionals for the description of the bonds formed by helium, argon, krypton and xenon with various open-shell atoms. This evaluation has been done on model molecular systems for which precise experimental data are available and reference post-Hartree-Fock calculations (CCSD(T) using large basis sets) are feasible. The results show that when the rare gas atom shares density with the neighbouring atoms, the GGA functionals yield good geometries and qualitatively correct binding energies, even if these are quite significantly overestimated. The use of hybrid functionals enables us to obtain good geometries and satisfactory binding energies. For compounds in which the rare gas atom forms weak dispersive-like bonding, the accuracy yielded by the various functionals is not as good. No functional gives satisfactory binding energies for all the compounds investigated. Several GGA and hybrid functionals yield correct geometries, even if some isomers are not obtained. One GGA functional (PBE) yields qualitatively correct results for the compounds of the three rare gases and several hybrid functionals give satisfactory energies for He compounds. The addition of an empirical dispersive correction improves the results on association compounds, but several isomers are not found.

Assessment of density functional theory for bonds formed between rare gases and open-shell atoms: a computational study of small molecules containing He, Ar, Kr and Xe

International Nuclear Information System (INIS)

Bertolus, Marjorie; Major, Mohamed; Brenner, Valerie

2012-01-01

The validity of the description of the DFT approximations currently implemented in plane wave DFT codes (LDA, GGA, meta-GGA, hybrid, GGA + empirical dispersion correction) for interactions between rare gases and open-shell atoms which form materials is poorly known. We have performed a first assessment of the accuracy of these functionals for the description of the bonds formed by helium, argon, krypton and xenon with various open-shell atoms. This evaluation has been done on model molecular systems for which precise experimental data are available and reference post-Hartree-Fock calculations (CCSD(T) using large basis sets) are feasible. The results show that when the rare gas atom shares density with the neighbouring atoms, the GGA functionals yield good geometries and qualitatively correct binding energies, even if these are quite significantly overestimated. The use of hybrid functionals enables us to obtain good geometries and satisfactory binding energies. For compounds in which the rare gas atom forms weak dispersive-like bonding, the accuracy yielded by the various functionals is not as good. No functional gives satisfactory binding energies for all the compounds investigated. Several GGA and hybrid functionals yield correct geometries, even if some isomers are not obtained. One GGA functional (PBE) yields qualitatively correct results for the compounds of the three rare gases and several hybrid functionals give satisfactory energies for He compounds. The addition of an empirical dispersive correction improves the results on association compounds, but several isomers are not found. (authors)

Shell structure and orbit bifurcations in finite fermion systems

Science.gov (United States)

Magner, A. G.; Yatsyshyn, I. S.; Arita, K.; Brack, M.

2011-10-01

We first give an overview of the shell-correction method which was developed by V.M. Strutinsky as a practicable and efficient approximation to the general self-consistent theory of finite fermion systems suggested by A.B. Migdal and collaborators. Then we present in more detail a semiclassical theory of shell effects, also developed by Strutinsky following original ideas of M.C. Gutzwiller. We emphasize, in particular, the influence of orbit bifurcations on shell structure. We first give a short overview of semiclassical trace formulae, which connect the shell oscillations of a quantum system with a sum over periodic orbits of the corresponding classical system, in what is usually called the "periodic orbit theory". We then present a case study in which the gross features of a typical double-humped nuclear fission barrier, including the effects of mass asymmetry, can be obtained in terms of the shortest periodic orbits of a cavity model with realistic deformations relevant for nuclear fission. Next we investigate shell structures in a spheroidal cavity model which is integrable and allows for far-going analytical computation. We show, in particular, how period-doubling bifurcations are closely connected to the existence of the so-called "superdeformed" energy minimum which corresponds to the fission isomer of actinide nuclei. Finally, we present a general class of radial power-law potentials which approximate well the shape of a Woods-Saxon potential in the bound region, give analytical trace formulae for it and discuss various limits (including the harmonic oscillator and the spherical box potentials).

Two-Loop Self-Energy Correction in a Strong Coulomb Nuclear Field

International Nuclear Information System (INIS)

Yerokhin, V.A.; Indelicato, P.; Shabaev, V.M.

2005-01-01

The two-loop self-energy correction to the ground-state energy levels of hydrogen-like ions with nuclear charges Z ≥ 10 is calculated without the Zα expansion, where α is the fine-structure constant. The data obtained are compared with the results of analytical calculations within the Zα expansion; significant disagreement with the analytical results of order α 2 (Zα) 6 has been found. Extrapolation is used to obtain the most accurate value for the two-loop self-energy correction for the 1s state in hydrogen

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

Thin-shell wormholes in dilaton gravity

International Nuclear Information System (INIS)

Eiroa, Ernesto F.; Simeone, Claudio

2005-01-01

In this work we construct charged thin-shell Lorentzian wormholes in dilaton gravity. The exotic matter required for the construction is localized in the shell and the energy conditions are satisfied outside the shell. The total amount of exotic matter is calculated and its dependence with the parameters of the model is analyzed

Synthesis of parallel and antiparallel core-shell triangular nanoparticles

Science.gov (United States)

Bhattacharjee, Gourab; Satpati, Biswarup

2018-04-01

Core-shell triangular nanoparticles were synthesized by seed mediated growth. Using triangular gold (Au) nanoparticle as template, we have grown silver (Ag) shellto get core-shell nanoparticle. Here by changing the chemistry we have grown two types of core-shell structures where core and shell is having same symmetry and also having opposite symmetry. Both core and core-shell nanoparticles were characterized using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) to know the crystal structure and composition of these synthesized core-shell nanoparticles. From diffraction pattern analysis and energy filtered TEM (EFTEM) we have confirmed the crystal facet in core is responsible for such two dimensional growth of core-shell nanostructures.

Polarization correction in the theory of energy losses by charged particles

Energy Technology Data Exchange (ETDEWEB)

Makarov, D. N., E-mail: makarovd0608@yandex.ru; Matveev, V. I. [Lomonosov Northern (Arctic) Federal University (Russian Federation)

2015-05-15

A method for finding the polarization (Barkas) correction in the theory of energy losses by charged particles in collisions with multielectron atoms is proposed. The Barkas correction is presented in a simple analytical form. We make comparisons with experimental data and show that applying the Barkas correction improves the agreement between theory and experiment.

Many-Body Energy Decomposition with Basis Set Superposition Error Corrections.

Science.gov (United States)

Mayer, István; Bakó, Imre

2017-05-09

The problem of performing many-body decompositions of energy is considered in the case when BSSE corrections are also performed. It is discussed that the two different schemes that have been proposed go back to the two different interpretations of the original Boys-Bernardi counterpoise correction scheme. It is argued that from the physical point of view the "hierarchical" scheme of Valiron and Mayer should be preferred and not the scheme recently discussed by Ouyang and Bettens, because it permits the energy of the individual monomers and all the two-body, three-body, etc. energy components to be free of unphysical dependence on the arrangement (basis functions) of other subsystems in the cluster.

Fundamental Study of two Selected Tropical Biomasses for Energy : coconut and cashew nut shells

OpenAIRE

Tsamba, Alberto Júlio

2008-01-01

 Cashew nut and coconut shells are two potential renewable and environmentally friendly energy sources that are commonly found as agro-industrial wastes in tropical countries. Despite this fact, they are not yet widely studied as such. Given this lack of specific technical and reliable data, technologies for their conversion into energy cannot be designed with confidence as it happens with other commonly studied biomass feedstock. Thus, the need to generate these data guided this research in ...

Inner shells as a link between atomic and nuclear physics

International Nuclear Information System (INIS)

Merzbacher, E.

1982-01-01

Nuclear decay and reaction processes generally take place in neutral or partially ionized atoms. The effects of static nuclear properties (size, shape, moments) on atomic spectra are well known, as are electronic transitions accompanying nuclear transitions, e.g. K capture and internal conversion. Excitation or ionization of initially filled inner shells, really or virtually, may modify nuclear Q values, will require correction to measured beta-decay endpoint energies, and can permit the use of inner-shell transitions in the determination of nuclear widths. Improvements in resolution continue to enhance the importance of these effects. There is also beginning to appear experimental evidence of the dynamical effects of atomic electrons on the course of nuclear reactions. The dynamics of a nuclear reaction, which influences and may in turn be influenced by atomic electrons in inner shells, offers instructive examples of the interplay between strong and electromagnetic interactions and raises interesting questions about coherence properties of particle beams. A variety of significantly different collision regimes, depending on the atomic numbers of the collision partners and the collision velocity, will be discussed and illustrated. 21 References, 5 figures

NLO QCD+EW predictions for V + jets including off-shell vector-boson decays and multijet merging

Energy Technology Data Exchange (ETDEWEB)

Kallweit, S. [Institut für Physik & PRISMA Cluster of Excellence,Johannes Gutenberg Universität, 55099 Mainz (Germany); Lindert, J.M. [Physik-Institut, Universität Zürich,Winterthurerstrasse 190, CH-8057 Zürich (Switzerland); Maierhöfer, P. [Institute for Particle Physics Phenomenology, Durham University,Durham DH1 3LE (United Kingdom); Physikalisches Institut, Albert-Ludwigs-Universität Freiburg,79104 Freiburg (Germany); Pozzorini, S.; Schönherr, M. [Physik-Institut, Universität Zürich,Winterthurerstrasse 190, CH-8057 Zürich (Switzerland)

2016-04-05

We present next-to-leading order (NLO) predictions including QCD and electroweak (EW) corrections for the production and decay of off-shell electroweak vector bosons in association with up to two jets at the 13 TeV LHC. All possible dilepton final states with zero, one or two charged leptons that can arise from off-shell W and Z bosons or photons are considered. All predictions are obtained using the automated implementation of NLO QCD+EW corrections in the OPENLOOPS matrix-element generator combined with the MUNICH and SHERPA Monte Carlo frameworks. Electroweak corrections play an especially important role in the context of BSM searches, due to the presence of large EW Sudakov logarithms at the TeV scale. In this kinematic regime, important observables such as the jet transverse momentum or the total transverse energy are strongly sensitive to multijet emissions. As a result, fixed-order NLO QCD+EW predictions are plagued by huge QCD corrections and poor theoretical precision. To remedy this problem we present an approximate method that allows for a simple and reliable implementation of NLO EW corrections in the MEPS@NLO multijet merging framework. Using this general approach we present an inclusive simulation of vector-boson production in association with jets that guarantees NLO QCD+EW accuracy in all phase-space regions involving up to two resolved jets.

Unified description of pf-shell nuclei by the Monte Carlo shell model calculations

Energy Technology Data Exchange (ETDEWEB)

Mizusaki, Takahiro; Otsuka, Takaharu [Tokyo Univ. (Japan). Dept. of Physics; Honma, Michio

1998-03-01

The attempts to solve shell model by new methods are briefed. The shell model calculation by quantum Monte Carlo diagonalization which was proposed by the authors is a more practical method, and it became to be known that it can solve the problem with sufficiently good accuracy. As to the treatment of angular momentum, in the method of the authors, deformed Slater determinant is used as the basis, therefore, for making angular momentum into the peculiar state, projected operator is used. The space determined dynamically is treated mainly stochastically, and the energy of the multibody by the basis formed as the result is evaluated and selectively adopted. The symmetry is discussed, and the method of decomposing shell model space into dynamically determined space and the product of spin and isospin spaces was devised. The calculation processes are shown with the example of {sup 50}Mn nuclei. The calculation of the level structure of {sup 48}Cr with known exact energy can be done with the accuracy of peculiar absolute energy value within 200 keV. {sup 56}Ni nuclei are the self-conjugate nuclei of Z=N=28. The results of the shell model calculation of {sup 56}Ni nucleus structure by using the interactions of nuclear models are reported. (K.I.)

Relativistic MR–MP Energy Levels for L-shell Ions of Silicon

Science.gov (United States)

Santana, Juan A.; Lopez-Dauphin, Nahyr A.; Beiersdorfer, Peter

2018-01-01

Level energies are reported for Si V, Si VI, Si VII, Si VIII, Si IX, Si X, Si XI, and Si XII. The energies have been calculated with the relativistic Multi-Reference Møller–Plesset Perturbation Theory method and include valence and K-vacancy states with nl up to 5f. The accuracy of the calculated level energies is established by comparison with the recommended data listed in the National Institute of Standards and Technology (NIST) online database. The average deviation of valence level energies ranges from 0.20 eV in Si V to 0.04 eV in Si XII. For K-vacancy states, the available values recommended in the NIST database are limited to Si XII and Si XIII. The average energy deviation is below 0.3 eV for K-vacancy states. The extensive and accurate data set presented here greatly augments the amount of available reference level energies. We expect our data to ease the line identification of L-shell ions of Si in celestial sources and laboratory-generated plasmas, and to serve as energy references in the absence of more accurate laboratory measurements.

High-performance asymmetric supercapacitors based on core/shell cobalt oxide/carbon nanowire arrays with enhanced electrochemical energy storage

International Nuclear Information System (INIS)

Pan, G.X.; Xia, X.H.; Cao, F.; Chen, J.; Tang, P.S.; Zhang, Y.J.; Chen, H.F.

2014-01-01

Graphical abstract: - Highlights: • We prepared a self-supported porous Co 3 O 4 /C core/shell nanowire array. • Core/shell nanowire array showed high pseudo-capacitive properties. • Core/shell array structure was favorable for fast ion and electron transfer. - Abstract: High-reactivity electrode materials are indispensible for developing high-performance electrochemical energy storage devices. Herein, we report self-supported core/shell Co 3 O 4 /C nanowire arrays by using hydrothermal synthesis and chemical vapor deposition methods. A uniform and thin carbon shell is coated on the surface of Co 3 O 4 nanowire forming core/shell nanowires with diameters of ∼100 nm. Asymmetric supercapacitors have been assembled with the core/shell Co 3 O 4 /C nanowire arrays as the positive electrode and activated carbon (AC) as the negative electrode. The core/shell Co 3 O 4 /C nanowire arrays exhibit a specific capacity of 116 mAh g −1 at the working current of 100 mA (4 A g −1 ), and a long cycle life along with ∼ 92% retention after 8000 cycles at 4 A g −1 , higher than the unmodified Co 3 O 4 nanowire arrays (81 mAh g −1 at 4 A g −1 ). The introduction of uniform carbon layer into the core/shell structure is favorable for the enhancement of supercapacitor due to the improved electrical conductivity and reaction kinetics

Active Full-Shell Grazing-Incidence Optics

Science.gov (United States)

Davis, Jacqueline M.; Elsner, Ronald F.; Ramsey, Brian D.; O'Dell, Stephen L.; Kolodziejczak, Jeffery; Weisskopf, Martin C.; Gubarev, Mikhail V.

2016-01-01

MSFC has a long history of developing full-shell grazing-incidence x-ray optics for both narrow (pointed) and wide field (surveying) applications. The concept presented in this paper shows the potential to use active optics to switch between narrow and wide-field geometries, while maintaining large effective area and high angular resolution. In addition, active optics has the potential to reduce errors due to mounting and manufacturing lightweight optics. The design presented corrects low spatial frequency error and has significantly fewer actuators than other concepts presented thus far in the field of active x-ray optics. Using a finite element model, influence functions are calculated using active components on a full-shell grazing-incidence optic. Next, the ability of the active optic to effect a change of optical prescription and to correct for errors due to manufacturing and mounting is modeled.

Triggered Snap-Through of Bistable Shells

Science.gov (United States)

Cai, Yijie; Huang, Shicheng; Trase, Ian; Hu, Nan; Chen, Zi

Elastic bistable shells are common structures in nature and engineering, such as the lobes of the Venus flytrap or the surface of a toy jumping poppers. Despite their ubiquity, the parameters that control the bistability of such structures are not well understood. In this study, we explore how the geometrical features of radially symmetric elastic shells affect the shape and potential energy of a shell's stable states, and how to tune certain parameters in order to generate a snap-through transition from a convex semi-stable state to concave stable state. We fabricated a series of elastic shells with varying geometric parameters out of silicone rubber and measured the resulting potential energy in the semi-stable state. Finite element simulations were also conducted in order to determine the deformation and stress in the shells during snap-through. It was found that the energy of the semi-stable state is controlled by only two geometric parameters and a dimensionless ratio. We also noted two distinct transitions during snap-through, one between monostability and semi-bistability (the state a popper toy is in before it snaps-through and jumps), and a second transition between semi-bistability and true bistability. This work shows that it is possible to use a set of simple parameters to tailor the energy landscape of an elastic shell in order to generate complex trigger motions for their potential use in smart applications. Z.C. acknowledge support from Society in Science-Branco Weiss Fellowship, administered by ETH Zurich.

75 FR 17036 - Energy Conservation Program: Energy Conservation Standards for Small Electric Motors; Correction

Science.gov (United States)

2010-04-05

... Conservation Program: Energy Conservation Standards for Small Electric Motors; Correction AGENCY: Office of... standards for small electric motors, which was published on March 9, 2010. In that final rule, the U.S... titled ``Energy Conservation Standards for Small Electric Motors.'' 75 FR 10874. Since the publication of...

Calculation of the effective D-d neutron energy distribution incident on a cylindrical shell sample

International Nuclear Information System (INIS)

Gotoh, Hiroshi

1977-07-01

A method is proposed to calculate the effective energy distribution of neutrons incident on a cylindrical shell sample placed perpendicularly to the direction of the deuteron beam bombarding a deuterium metal target. The Monte Carlo method is used and the Fortran program is contained. (auth.)

Empirically Determined Response Matrices for On-Line Orbit and Energy Correction at Jefferson Lab

International Nuclear Information System (INIS)

Leigh Harwood; Alicia Hofler; Michele Joyce; Valeri Lebedev; David Bryan

2001-01-01

Jefferson Lab uses feedback loops (less than 1 hertz update rate) to correct drifts in CEBAF's electron beam orbit and energy. Previous incarnations of these loops used response matrices that were computed by a numerical model of the machine. Jefferson Lab is transitioning this feedback system to use empirically determined response matrices whereby the software introduces small orbit or energy deviations using the loop's actuators and measures the system response with the loop's sensors. This method is in routine use for orbit correction. This paper will describe the orbit correction system and future plans to extend this method to energy correction

Energy dependence of photon-induced L-shell x-ray intensity ratios in some high-Z elements

Energy Technology Data Exchange (ETDEWEB)

Shatendra, K; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

1983-12-14

The L-shell x-ray intensity ratios in Au, Pb, Th and U at various photon energies have been measured and their energy dependence is studied. A comparison of the experimental values is made with those calculated using the x-ray emission rates and subshell photoelectric cross sections, subshell fluorescence yields and Coster-Kronig transition probabilities and fairly good agreement is observed.

Complete Surface Mapping of ICF Shells

International Nuclear Information System (INIS)

Stephens, R.B.; Olson, D.; Huang, H.; Gibson, J.B.

2004-01-01

Inertial confinement fusion shells have previously been evaluated on the basis of microscopic examination for local defects and limited surface profiling to represent their average fluctuation power. Since defects are local, and don't always have visible edges, this approach both misses some important fluctuations and doesn't properly represent the spatially dependent surface fluctuation power. We have taken the first step toward correcting this problem by demonstrating the capability to completely map the surface of a NIF shell with the resolution to account for all modes. This allows complete accounting of all the surface fluctuations. In the future this capability could be used for valuable shells to generate a complete r(θ, φ) surface map for accurate 3-D modeling of a shot

COMPLETE SURFACE MAPPING OF ICF SHELLS

International Nuclear Information System (INIS)

STEPHENS, R.B.; OLSON, D.; HUANG, H.; GIBSON, J.B.

2003-09-01

OAK-B135 Inertial confinement fusion shells have previously been evaluated on the basis of microscopic examination for local defects and limited surface profiling to represent their average fluctuation power. Since defects are local, and don't always have visible edges, this approach both misses some important fluctuations and doesn't properly represent the spatially dependent surface fluctuation power. they have taken the first step toward correcting this problem by demonstrating the capability to completely map the surface of a NIF shell with the resolution to account for all modes. This allows complete accounting of all the surface fluctuations. In the future this capability could be used for valuable shells to generate a complete r(θ,ψ) surface map for accurate 3-D modeling of a shot

Novel extrapolation method in the Monte Carlo shell model

International Nuclear Information System (INIS)

Shimizu, Noritaka; Abe, Takashi; Utsuno, Yutaka; Mizusaki, Takahiro; Otsuka, Takaharu; Honma, Michio

2010-01-01

We propose an extrapolation method utilizing energy variance in the Monte Carlo shell model to estimate the energy eigenvalue and observables accurately. We derive a formula for the energy variance with deformed Slater determinants, which enables us to calculate the energy variance efficiently. The feasibility of the method is demonstrated for the full pf-shell calculation of 56 Ni, and the applicability of the method to a system beyond the current limit of exact diagonalization is shown for the pf+g 9/2 -shell calculation of 64 Ge.

A shell approach for fibrous reinforcement forming simulations

Science.gov (United States)

Liang, B.; Colmars, J.; Boisse, P.

2018-05-01

Because of the slippage between fibers, the basic assumptions of classical plate and shell theories are not verified by fiber reinforcement during a forming. However, simulations of reinforcement forming use shell finite elements when wrinkles development is important. A shell formulation is proposed for the forming simulations of continuous fiber reinforcements. The large tensile stiffness leads to the quasi inextensibility in the fiber directions. The fiber bending stiffness determines the curvature of the reinforcement. The calculation of tensile and bending virtual works are based on the precise geometry of the single fiber. Simulations and experiments are compared for different reinforcements. It is shown that the proposed fibrous shell approach not only correctly simulates the deflections but also the rotations of the through thickness material normals.

Walnut shells: replacement for natural gas

Energy Technology Data Exchange (ETDEWEB)

Goss, J R; Williams, R O

1977-11-01

A method of extracting useful energy from cracked walnut shells has been developed by the University of California in co-operation with Diamond/Sunsweet, Inc., and the California Energy Resources Conservation and Development Commission. The technique involves converting the shells to producer gas, a low-Btu gas in which the major combustible components are carbon monoxide (20 to 30%) and hydrogen (10 to 15%).

Energy partition in nuclear fission

International Nuclear Information System (INIS)

Ruben, A.; Maerten, H.; Seeliger, D.

1990-01-01

A scission point model (two spheroid model TSM) including semi-empirical temperature-dependent shell correction energies for deformed fragments at scission is presented. It has been used to describe the mass-asymmetry-dependent partition of the total energy release on both fragments from spontaneous and induced fission. Characteristic trends of experimental fragment energy and neutron multiplicity data as function of incidence energy in the Th-Cf region of fissioning nuclei are well reproduced. Based on model applications, information on the energy dissipated during the descent from second saddle of fission barrier to scission point have been deduced. (author). 39 refs, 13 figs

Meeting the challenge of future energy supply from the perspective of Royal Dutch Shell. An interview with Matthias Bichsel

Energy Technology Data Exchange (ETDEWEB)

Bollinger, D. (ed.); Gunzenhauser, B. [Vice-President of the Association of Swiss Petroleum Geologists and Engineers, c/o Interoil AG, Zuerich (Switzerland)

2009-07-01

In this comprehensive interview in the Swiss Bulletin for Practical Geology with Matthias Bichsel, Director of Projects and Technology at Royal Dutch Shell plc, the subject of 'Peak Oil' is discussed. The question is asked on how Shell deals with the fact that oil and gas resources are limited and sooner or later will be more or less depleted or can only be used at high cost. A further topic discussed deals with how Shell wants to satisfy current shareholder interests. At the same time the company needs to be led into a viable and successful future. Shell's efforts to position itself in this difficult situation are discussed. The development of resource estimates, environmental responsibility and sustainability are further topics examined. Current scenarios are looked at and how Shell aims to solve the dilemma of meeting doubling energy demand is discussed. Finally, new technologies and renewable alternatives are looked at

Gross shell structure of moments of inertia

International Nuclear Information System (INIS)

Deleplanque, M.A.; Frauendorf, S.; Pashkevich, V.V.; Chu, S.Y.; Unzhakova, A.

2002-01-01

Average yrast moments of inertia at high spins, where the pairing correlations are expected to be largely absent, were found to deviate from the rigid-body values. This indicates that shell effects contribute to the moment of inertia. We discuss the gross dependence of moments of inertia and shell energies on the neutron number in terms of the semiclassical periodic orbit theory. We show that the ground-state shell energies, nuclear deformations and deviations from rigid-body moments of inertia are all due to the same periodic orbits

Novel scatter compensation with energy and spatial dependent corrections in positron emission tomography

International Nuclear Information System (INIS)

Guerin, Bastien

2010-01-01

We developed and validated a fast Monte Carlo simulation of PET acquisitions based on the SimSET program modeling accurately the propagation of gamma photons in the patient as well as the block-based PET detector. Comparison of our simulation with another well validated code, GATE, and measurements on two GE Discovery ST PET scanners showed that it models accurately energy spectra (errors smaller than 4.6%), the spatial resolution of block-based PET scanners (6.1%), scatter fraction (3.5%), sensitivity (2.3%) and count rates (12.7%). Next, we developed a novel scatter correction incorporating the energy and position of photons detected in list-mode. Our approach is based on the reformulation of the list-mode likelihood function containing the energy distribution of detected coincidences in addition to their spatial distribution, yielding an EM reconstruction algorithm containing spatial and energy dependent correction terms. We also proposed using the energy in addition to the position of gamma photons in the normalization of the scatter sinogram. Finally, we developed a method for estimating primary and scatter photons energy spectra from total spectra detected in different sectors of the PET scanner. We evaluated the accuracy and precision of our new spatio-spectral scatter correction and that of the standard spatial correction using realistic Monte Carlo simulations. These results showed that incorporating the energy in the scatter correction reduces bias in the estimation of the absolute activity level by ∼ 60% in the cold regions of the largest patients and yields quantification errors less than 13% in all regions. (author)

K- and L-shell ionization cross sections for deuterons calculated in the ECPSSR theory

International Nuclear Information System (INIS)

Cohen, D.D.

1989-01-01

Ionization cross sections for K and L subshells are tabulated according to target atomic number and incident deuteron energy. Deuteron energies between 100 keV and 10 MeV and selected targets between C and Am for the K shell and between Ar and Am for the L subshells are used. The cross sections have been calculated in the plane-wave Born approximation (PWBA) with corrections for energy loss (E), Coulomb deflection (C), perturbed stationary states (PSS), and relativistic (R) effects (ECPSSR). Differences between the computational approach of Cohen and Harrigan and that of Brandt and Lapicki are delineated, and the ratios of the resulting cross sections are tabulated. Copyright 1989 Academic Press, Inc

Driven self-assembly of hard nanoplates on soft elastic shells

International Nuclear Information System (INIS)

Zhang Yao-Yang; Hua Yun-Feng; Deng Zhen-Yu

2015-01-01

The driven self-assembly behaviors of hard nanoplates on soft elastic shells are investigated by using molecular dynamics (MD) simulation method, and the driven self-assembly structures of adsorbed hard nanoplates depend on the shape of hard nanoplates and the bending energy of soft elastic shells. Three main structures for adsorbed hard nanoplates, including the ordered aggregation structures of hard nanoplates for elastic shells with a moderate bending energy, the collapsed structures for elastic shells with a low bending energy, and the disordered aggregation structures for hard shells, are observed. The self-assembly process of adsorbed hard nanoplates is driven by the surface tension of the elastic shell, and the shape of driven self-assembly structures is determined on the basis of the minimization of the second moment of mass distribution. Meanwhile, the deformations of elastic shells can be controlled by the number of adsorbed rods as well as the length of adsorbed rods. This investigation can help us understand the complexity of the driven self-assembly of hard nanoplates on elastic shells. (paper)

M-shell ionization of heavy elements by 0.1-1.0 MeV/amu 1,2H and 3,4He ions

International Nuclear Information System (INIS)

Pajek, M.; Banas, D.; Braziewicz, J.; Czarnota, M.; Bienkowski, A.; Jaskola, M.; Korman, A.; Trautmann, D.; Lapicki, G.

2006-01-01

The M-shell ionization in high-Z atoms by low-energy light 1 1 H, 1 2 H, 2 3 He, and 2 4 He ions have been studied systematically in the energy range 0.1-1.0 MeV/amu in order to verify the available theoretical approaches describing the M-shell ionization by charged particles in asymmetric collisions. The present low-energy data, combined with our earlier results reported for M-shell ionization by hydrogen and helium ions for higher energies, form a systematic experimental basis to test the theoretical predictions of M-shell ionization based on the plane-wave Born approximation (PWBA), the semiclassical approximation (SCA), and the binary-encounter approximation (BEA). In the PWBA based approaches the energy loss (E), Coulomb deflection (C), perturbed stationary state (PSS), and relativistic (R) effects were considered within the ECPSSR theory and its recent modification, called the ECUSAR theory, in which a description of the PSS effect was corrected to account for the united- and separated-atom (USA) electron binding energy limits. In the SCA calculations with relativistic wave functions the binding effect was included only in the limiting cases of separated-atom and united-atom limits. Possible contribution of the electron capture, multiple ionization, and recoil ionization to the M-shell vacancy production, which is dominated for light ions impact by direct single ionization process, are also discussed. The universal scaling of measured M-shell x-ray production and ionization cross sections was investigated in detail. Using the present data the isotopic effect has been studied by comparing the measured M-shell ionization cross-section ratios for equal-velocity hydrogen 1 1 H and 1 2 H as well as helium 2 3 He and 2 4 He isotopes. In addition, the ratios of measured ionization cross sections for 1 2 H and 2 4 He were used to investigate the role of the binding effect. The present results are of practical importance for the application of particle-induced x

Evidence for higher-order effects in L-shell ionization by proton impact

International Nuclear Information System (INIS)

Sarkadi, L.; Mukoyama, T.

1988-01-01

It is widely believed that higher order processes of ion-atom collisions are negligible in cases of light projectiles like proton. Recent refined experiments tried to prove that the existence of such effects were comperable with the experimental errors, and they showed the unexpected relative importance of the higher order processes. Thus a new coupled channel calculation was performed for proton-gold atom collision in the energy range of 0.15-3.0 MeV, including dynamical subshell coupling effects. The results show that the deviations from the first order cross sections reach 40% at low collision energy. This result made necessary to correct the calculations of L-shell X-ray production cross sections. (D.G.) 6 refs

Atomic inner-shell physics

International Nuclear Information System (INIS)

Crasemann, B.

1985-01-01

This book discusses: relativistic and quantum electrodynamic effects on atomic inner shells; relativistic calculation of atomic transition probabilities; many-body effects in energetic atomic transitions; Auger Electron spectrometry of core levels of atoms; experimental evaluation of inner-vacancy level energies for comparison with theory; mechanisms for energy shifts of atomic K-X rays; atomic physics research with synchrotron radiation; investigations of inner-shell states by the electron energy-loss technique at high resolution; coherence effects in electron emission by atoms; inelastic X-ray scattering including resonance phenomena; Rayleigh scattering: elastic photon scattering by bound electrons; electron-atom bremsstrahlung; X-ray and bremsstrahlung production in nuclear reactions; positron production in heavy-ion collisions, and X-ray processes in heavy-ion collisions

Deriving the nuclear shell model from first principles

Science.gov (United States)

Barrett, Bruce R.; Dikmen, Erdal; Vary, James P.; Maris, Pieter; Shirokov, Andrey M.; Lisetskiy, Alexander F.

2014-09-01

The results of an 18-nucleon No Core Shell Model calculation, performed in a large basis space using a bare, soft NN interaction, can be projected into the 0 ℏω space, i.e., the sd -shell. Because the 16 nucleons in the 16O core are frozen in the 0 ℏω space, all the correlations of the 18-nucleon system are captured by the two valence, sd -shell nucleons. By the projection, we obtain microscopically the sd -shell 2-body effective interactions, the core energy and the sd -shell s.p. energies. Thus, the input for standard shell-model calculations can be determined microscopically by this approach. If the same procedure is then applied to 19-nucleon systems, the sd -shell 3-body effective interactions can also be obtained, indicating the importance of these 3-body effective interactions relative to the 2-body effective interactions. Applications to A = 19 and heavier nuclei with different intrinsic NN interactions will be presented and discussed. The results of an 18-nucleon No Core Shell Model calculation, performed in a large basis space using a bare, soft NN interaction, can be projected into the 0 ℏω space, i.e., the sd -shell. Because the 16 nucleons in the 16O core are frozen in the 0 ℏω space, all the correlations of the 18-nucleon system are captured by the two valence, sd -shell nucleons. By the projection, we obtain microscopically the sd -shell 2-body effective interactions, the core energy and the sd -shell s.p. energies. Thus, the input for standard shell-model calculations can be determined microscopically by this approach. If the same procedure is then applied to 19-nucleon systems, the sd -shell 3-body effective interactions can also be obtained, indicating the importance of these 3-body effective interactions relative to the 2-body effective interactions. Applications to A = 19 and heavier nuclei with different intrinsic NN interactions will be presented and discussed. Supported by the US NSF under Grant No. 0854912, the US DOE under

β-particle energy-summing correction for β-delayed proton emission measurements

Energy Technology Data Exchange (ETDEWEB)

Meisel, Z., E-mail: meisel@ohio.edu [Institute of Nuclear and Particle Physics, Department of Physics and Astronomy, Ohio University, Athens, OH 45701 (United States); Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements (United States); Santo, M. del [Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements, National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Crawford, H.L. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Cyburt, R.H. [Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements, National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Grinyer, G.F. [Grand Accélérateur National d' Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Bvd Henri Becquerel, Caen 14076 (France); Langer, C. [Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements, Institute for Applied Physics, Goethe University Frankfurt am Main, 60438 Frankfurt am Main (Germany); Montes, F. [Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements, National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Schatz, H. [Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements, National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Smith, K. [Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements, Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States)

2017-02-01

A common approach to studying β-delayed proton emission is to measure the energy of the emitted proton and corresponding nuclear recoil in a double-sided silicon-strip detector (DSSD) after implanting the β-delayed proton-emitting (βp) nucleus. However, in order to extract the proton-decay energy, the measured energy must be corrected for the additional energy implanted in the DSSD by the β-particle emitted from the βp nucleus, an effect referred to here as β-summing. We present an approach to determine an accurate correction for β-summing. Our method relies on the determination of the mean implantation depth of the βp nucleus within the DSSD by analyzing the shape of the total (proton + recoil + β) decay energy distribution shape. We validate this approach with other mean implantation depth measurement techniques that take advantage of energy deposition within DSSDs upstream and downstream of the implantation DSSD.

Improving quantitative dosimetry in (177)Lu-DOTATATE SPECT by energy window-based scatter corrections

DEFF Research Database (Denmark)

de Nijs, Robin; Lagerburg, Vera; Klausen, Thomas L

2014-01-01

and the activity, which depends on the collimator type, the utilized energy windows and the applied scatter correction techniques. In this study, energy window subtraction-based scatter correction methods are compared experimentally and quantitatively. MATERIALS AND METHODS: (177)Lu SPECT images of a phantom...... technique, the measured ratio was close to the real ratio, and the differences between spheres were small. CONCLUSION: For quantitative (177)Lu imaging MEGP collimators are advised. Both energy peaks can be utilized when the ESSE correction technique is applied. The difference between the calculated...

A Coulomb-Like Off-Shell T-Matrix with the Correct Coulomb Phase Shift

International Nuclear Information System (INIS)

Oryu, Shinsho; Watanabe, Takashi; Hiratsuka, Yasuhisa; Togawa, Yoshio

2017-01-01

We confirm the reliability of the well-known Coulomb renormalization method (CRM). It is found that the CRM is only available for a very-long-range screened Coulomb potential (SCP). However, such an SCP calculation in momentum space is considerably difficult because of the cancellation of significant digits. In contrast to the CRM, we propose a new method by using an on-shell equivalent SCP and the rest term. The two-potential theory with r-space is introduced, which defines fully the off-shell Coulomb amplitude. (author)

Experimental Guidance of ISB Corrections via Direct Nuclear Reactions

Science.gov (United States)

Leach, K. G.; Garrett, P. E.; Ball, G. C.; Bangay, J. C.; Bianco, L.; Demand, G. A.; Faestermann, T.; Finlay, P.; Green, K. L.; Hertenberger, R.; Kriicken, R.; Phillips, A. A.; Rand, E. T.; Sumithrarachchi, C. S.; Svensson, C. E.; Towner, I. S.; Triambak, S.; Wirth, H.-F.; Wong, J.

2011-09-01

The most recent isospin-symmetry-breaking corrections, δc, of Towner and Hardy for superallowed Fermi β-decay transitions, have included the opening of specific core orbitals. This change has resulted in significant deviations in some of the δc factors from their previous calculations, and an improved agreement of the individual corrected Script Ft values with the overall world average of the 13 most precise cases. While this is consistent with the conserved-vector-current (CVC) hypothesis of the Standard Model, these new calculations must be thoroughly tested, and guidance must be given for the improvement of calculations for the upper-pf shell nuclei. Using the (d,t) reaction mechanism to probe the single neutron wavefunction overlap, information regarding the relevant shell-model configurations needed in the calculation can be determined. An experiment was therefore performed with a 22 MeV polarized deuterium beam from the MP tandem Van de Graaff accelerator in Munich, Germany. Using the Q3D magnetic spectrograph, and a cathode-strip focal-plane detector, outgoing tritons were analyzed at 9 angles between 10° and 60°, up to an excitation energy of 4.8 MeV. This proceeding reports the motivational and experimental details for the 64Zn(d,t)63Zn transfer work presented.

Toward the AdS/CFT gravity dual for high energy collisions. III. Gravitationally collapsing shell and quasiequilibrium

International Nuclear Information System (INIS)

Lin, Shu; Shuryak, Edward

2008-01-01

The equilibration of matter and onset of hydrodynamics can be understood in the AdS/CFT context as a gravitational collapse process, in which 'collision debris' create a horizon. In this paper we consider the simplest geometry possible, a flat shell (or membrane) falling in the holographic direction toward the horizon. The metric is a combination of two well-known solutions: thermal AdS above the shell and pure AdS below, while motion of the shell is given by the Israel junction condition. Furthermore, when the shell motion can be considered slow, we were able to solve for two-point functions of all boundary stress tensors and found that an observer on the boundary sees a very peculiar quasiequilibrium: while the average stress tensor μν> contains the equilibrium plasma energy and pressure at all times, the spectral densities of the correlators (related with occupation probabilities of the modes) reveal additional oscillating terms absent in equilibrium. This is explained by the echo phenomenon, a partial return of the field coherence at certain echo times.

Effects of zonal flows on correlation between energy balance and energy conservation associated with nonlinear nonviscous atmospheric dynamics in a thin rotating spherical shell

Science.gov (United States)

Ibragimov, Ranis N.

2018-03-01

The nonlinear Euler equations are used to model two-dimensional atmosphere dynamics in a thin rotating spherical shell. The energy balance is deduced on the basis of two classes of functorially independent invariant solutions associated with the model. It it shown that the energy balance is exactly the conservation law for one class of the solutions whereas the second class of invariant solutions provides and asymptotic convergence of the energy balance to the conservation law.

Corrected Statistical Energy Analysis Model for Car Interior Noise

Directory of Open Access Journals (Sweden)

A. Putra

2015-01-01

Full Text Available Statistical energy analysis (SEA is a well-known method to analyze the flow of acoustic and vibration energy in a complex structure. For an acoustic space where significant absorptive materials are present, direct field component from the sound source dominates the total sound field rather than a reverberant field, where the latter becomes the basis in constructing the conventional SEA model. Such environment can be found in a car interior and thus a corrected SEA model is proposed here to counter this situation. The model is developed by eliminating the direct field component from the total sound field and only the power after the first reflection is considered. A test car cabin was divided into two subsystems and by using a loudspeaker as a sound source, the power injection method in SEA was employed to obtain the corrected coupling loss factor and the damping loss factor from the corrected SEA model. These parameters were then used to predict the sound pressure level in the interior cabin using the injected input power from the engine. The results show satisfactory agreement with the directly measured SPL.

Collapse analysis of toroidal shell

International Nuclear Information System (INIS)

Pomares, R.J.

1990-01-01

This paper describes a study performed to determine the collapse characteristics of a toroidal shell using finite element method (FEM) analysis. The study also included free drop testing of a quarter scale prototype to verify the analytical results. The full sized toroidal shell has a 24-inch toroidal diameter with a 24-inch tubal diameter. The shell material is type 304 strainless steel. The toroidal shell is part of the GE Model 2000 transportation packaging, and acts as an energy absorbing device. The analyses performed were on a full sized and quarter scaled models. The finite element program used in all analyses was the LIBRA code. The analytical procedure used both the elasto-plastic and large displacement options within the code. The loading applied in the analyses corresponded to an impact of an infinite rigid plane oriented normal to the drop direction vector. The application of the loading continued incrementally until the work performed by the deforming structure equalled the kinetic energy developed in the free fall. The comparison of analysis and test results showed a good correlation

Differential Deposition for Surface Figure Corrections in Grazing Incidence X-Ray Optics

Science.gov (United States)

Ramsey, Brian D.; Kilaru, Kiranmayee; Atkins, Carolyn; Gubarev, Mikhail V.; Broadway, David M.

2015-01-01

Differential deposition corrects the low- and mid- spatial-frequency deviations in the axial figure of Wolter-type grazing incidence X-ray optics. Figure deviations is one of the major contributors to the achievable angular resolution. Minimizing figure errors can significantly improve the imaging quality of X-ray optics. Material of varying thickness is selectively deposited, using DC magnetron sputtering, along the length of optic to minimize figure deviations. Custom vacuum chambers are built that can incorporate full-shell and segmented Xray optics. Metrology data of preliminary corrections on a single meridian of full-shell x-ray optics show an improvement of mid-spatial frequencies from 6.7 to 1.8 arc secs HPD. Efforts are in progress to correct a full-shell and segmented optics and to verify angular-resolution improvement with X-ray testing.

Nanostructured core-shell electrode materials for electrochemical capacitors

Science.gov (United States)

Jiang, Long-bo; Yuan, Xing-zhong; Liang, Jie; Zhang, Jin; Wang, Hou; Zeng, Guang-ming

2016-11-01

Core-shell nanostructure represents a unique system for applications in electrochemical energy storage devices. Owing to the unique characteristics featuring high power delivery and long-term cycling stability, electrochemical capacitors (ECs) have emerged as one of the most attractive electrochemical storage systems since they can complement or even replace batteries in the energy storage field, especially when high power delivery or uptake is needed. This review aims to summarize recent progress on core-shell nanostructures for advanced supercapacitor applications in view of their hierarchical architecture which not only create the desired hierarchical porous channels, but also possess higher electrical conductivity and better structural mechanical stability. The core-shell nanostructures include carbon/carbon, carbon/metal oxide, carbon/conducting polymer, metal oxide/metal oxide, metal oxide/conducting polymer, conducting polymer/conducting polymer, and even more complex ternary core-shell nanoparticles. The preparation strategies, electrochemical performances, and structural stabilities of core-shell materials for ECs are summarized. The relationship between core-shell nanostructure and electrochemical performance is discussed in detail. In addition, the challenges and new trends in core-shell nanomaterials development have also been proposed.

Core–shell interaction and its impact on the optical absorption of pure and doped core-shell CdSe/ZnSe nanoclusters

Energy Technology Data Exchange (ETDEWEB)

Wang, Xinqin; Cui, Yingqi; Zeng, Qun; Yang, Mingli, E-mail: myang@scu.edu.cn [Institute of Atomic and Molecular Physics, Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610065 (China); Yu, Shengping [College of Chemistry and Environment Protection Engineering, Southwest University for Nationalities, Chengdu 610041 (China)

2016-04-07

The structural, electronic, and optical properties of core-shell nanoclusters, (CdSe){sub x}@(CdSe){sub y} and their Zn-substituted complexes of x = 2–4 and y = 16–28, were studied with density functional theory calculations. The substitution was applied in the cores, the shells, and/or the whole clusters. All these clusters are characterized by their core-shell structures in which the core-shell interaction was found different from those in core or in shell, as reflected by their bondlengths, volumes, and binding energies. Moreover, the core and shell combine together to compose a new cluster with electronic and optical properties different from those of separated individuals, as reflected by their HOMO-LUMO gaps and optical absorptions. With the substitution of Cd by Zn, the structural, electronic, and optical properties of clusters change regularly. The binding energy increases with Zn content, attributed to the strong Zn–Se bonding. For the same core/shell, the structure with a CdSe shell/core has a narrower gap than that with a ZnSe shell/core. The optical absorption spectra also change accordingly with Zn substitution. The peaks blueshift with increasing Zn concentration, accompanying with shape variations in case large number of Cd atoms are substituted. Our calculations reveal the core-shell interaction and its influence on the electronic and optical properties of the core-shell clusters, suggesting a composition–structure–property relationship for the design of core-shell CdSe and ZnSe nanoclusters.

Single-loop renormalizations and properties of radiative corrections in the Fried-Yennie gauge

International Nuclear Information System (INIS)

Karshenboim, S.G.; Shelyuto, V.A.; Eides, M.I.

1988-01-01

Single-loop radiative corrections are studied in the Fried-Yennie gauge. It is shown that in this gauge the usual subtraction procedure on the mass shell does not require introduction of an infrared photon mass. The behavior of the diagrams containing radiative corrections near the mass shell is investigated, and it is shown that in the Fried-Yennie gauge this behavior is softer than in any other gauge and softer than the behavior of the corresponding graphs without radiative corrections

Wilson lines, Grassmannians and gauge invariant off-shell amplitudes in N=4 SYM

Energy Technology Data Exchange (ETDEWEB)

Bork, L.V. [Institute for Theoretical and Experimental Physics,Moscow (Russian Federation); The Center for Fundamental and Applied Research,All-Russia Research Institute of Automatics, Moscow (Russian Federation); Onishchenko, A.I. [Bogoliubov Laboratory of Theoretical Physics,Joint Institute for Nuclear Research, Dubna (Russian Federation); Moscow Institute of Physics and Technology State University,Dolgoprudny (Russian Federation); Skobeltsyn Institute of Nuclear Physics, Moscow State University,Moscow (Russian Federation)

2017-04-04

In this paper we consider tree-level gauge invariant off-shell amplitudes (Wilson line form factors) in N=4 SYM. For the off-shell amplitudes with one leg off-shell we present a conjecture for their Grassmannian integral representation in spinor helicity, twistor and momentum twistor parameterizations. The presented conjecture is successfully checked against BCFW results for MHV{sub n}, NMHV{sub 4} and NMHV{sub 5} off-shell amplitudes. We have also verified that our Grassmannian integral representation correctly reproduces soft (on-shell) limit for the off-shell gluon momentum. It is shown that the (deformed) off-shell amplitude expressions could be also obtained using quantum inverse scattering method for auxiliary gl(4|4) super spin chain.

Assessment of the accuracy of coupled cluster perturbation theory for open-shell systems. I. Triples expansions.

Science.gov (United States)

Eriksen, Janus J; Matthews, Devin A; Jørgensen, Poul; Gauss, Jürgen

2016-05-21

The accuracy at which total energies of open-shell atoms and organic radicals may be calculated is assessed for selected coupled cluster perturbative triples expansions, all of which augment the coupled cluster singles and doubles (CCSD) energy by a non-iterative correction for the effect of triple excitations. Namely, the second- through sixth-order models of the recently proposed CCSD(T-n) triples series [J. J. Eriksen et al., J. Chem. Phys. 140, 064108 (2014)] are compared to the acclaimed CCSD(T) model for both unrestricted as well as restricted open-shell Hartree-Fock (UHF/ROHF) reference determinants. By comparing UHF- and ROHF-based statistical results for a test set of 18 modest-sized open-shell species with comparable RHF-based results, no behavioral differences are observed for the higher-order models of the CCSD(T-n) series in their correlated descriptions of closed- and open-shell species. In particular, we find that the convergence rate throughout the series towards the coupled cluster singles, doubles, and triples (CCSDT) solution is identical for the two cases. For the CCSD(T) model, on the other hand, not only its numerical consistency, but also its established, yet fortuitous cancellation of errors breaks down in the transition from closed- to open-shell systems. The higher-order CCSD(T-n) models (orders n > 3) thus offer a consistent and significant improvement in accuracy relative to CCSDT over the CCSD(T) model, equally for RHF, UHF, and ROHF reference determinants, albeit at an increased computational cost.

Assessment of the accuracy of coupled cluster perturbation theory for open-shell systems. I. Triples expansions

Energy Technology Data Exchange (ETDEWEB)

Eriksen, Janus J., E-mail: janusje@chem.au.dk; Jørgensen, Poul [qLEAP Center for Theoretical Chemistry, Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Matthews, Devin A. [The Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712 (United States); Gauss, Jürgen [Institut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz, D-55128 Mainz (Germany)

2016-05-21

The accuracy at which total energies of open-shell atoms and organic radicals may be calculated is assessed for selected coupled cluster perturbative triples expansions, all of which augment the coupled cluster singles and doubles (CCSD) energy by a non-iterative correction for the effect of triple excitations. Namely, the second- through sixth-order models of the recently proposed CCSD(T–n) triples series [J. J. Eriksen et al., J. Chem. Phys. 140, 064108 (2014)] are compared to the acclaimed CCSD(T) model for both unrestricted as well as restricted open-shell Hartree-Fock (UHF/ROHF) reference determinants. By comparing UHF- and ROHF-based statistical results for a test set of 18 modest-sized open-shell species with comparable RHF-based results, no behavioral differences are observed for the higher-order models of the CCSD(T–n) series in their correlated descriptions of closed- and open-shell species. In particular, we find that the convergence rate throughout the series towards the coupled cluster singles, doubles, and triples (CCSDT) solution is identical for the two cases. For the CCSD(T) model, on the other hand, not only its numerical consistency, but also its established, yet fortuitous cancellation of errors breaks down in the transition from closed- to open-shell systems. The higher-order CCSD(T–n) models (orders n > 3) thus offer a consistent and significant improvement in accuracy relative to CCSDT over the CCSD(T) model, equally for RHF, UHF, and ROHF reference determinants, albeit at an increased computational cost.

Quantum corrections to the stress-energy tensor in thermodynamic equilibrium with acceleration

Science.gov (United States)

Becattini, F.; Grossi, E.

2015-08-01

We show that the stress-energy tensor has additional terms with respect to the ideal form in states of global thermodynamic equilibrium in flat spacetime with nonvanishing acceleration and vorticity. These corrections are of quantum origin and their leading terms are second order in the gradients of the thermodynamic fields. Their relevant coefficients can be expressed in terms of correlators of the stress-energy tensor operator and the generators of the Lorentz group. With respect to previous assessments, we find that there are more second-order coefficients and that all thermodynamic functions including energy density receive acceleration and vorticity dependent corrections. Notably, also the relation between ρ and p , that is, the equation of state, is affected by acceleration and vorticity. We have calculated the corrections for a free real scalar field—both massive and massless—and we have found that they increase, particularly for a massive field, at very high acceleration and vorticity and very low temperature. Finally, these nonideal terms depend on the explicit form of the stress-energy operator, implying that different stress-energy tensors of the scalar field—canonical or improved—are thermodynamically inequivalent.

L-shell X-ray production cross sections of Ce, Nd, Sm, Eu, Gd, and Dy by impact of {sup 14}N{sup 2+} ions with energies between 7.0 MeV and 10.5 MeV

Energy Technology Data Exchange (ETDEWEB)

Murillo, G.; Méndez, B.; López-Monroy, J. [Departamento de Aceleradores, Instituto Nacional de Investigaciones Nucleares, Carr. México-Toluca S/N, Ocoyoacac, Edo. Méx. 52750 (Mexico); Miranda, J., E-mail: miranda@fisica.unam.mx [Instituto de Física, Universidad Nacional Autónoma de México, A.P. 20-364, México, Cd. Mx. 01000 (Mexico); Villaseñor, P. [Departamento de Aceleradores, Instituto Nacional de Investigaciones Nucleares, Carr. México-Toluca S/N, Ocoyoacac, Edo. Méx. 52750 (Mexico)

2016-09-15

Highlights: • A new data set of L X-ray production cross sections by nitrogen ion impact is given. • The target elements have atomic numbers in the range 58–66 (lanthanoids). • A universal scaling as function of a reduced velocity variable is applied. • The eCPSSR model with EC and MI corrections gives very good results. - Abstract: L-shell X-ray production cross sections from the lanthanoid elements Ce, Nd, Sm, Eu, Gd, and Dy, induced by the impact of {sup 14}N{sup 2+} ions with energies in the interval 7.0 MeV to 10.5 MeV (0.50 MeV/μ to 0.75 MeV/μ), were measured and then compared with theoretical calculations obtained with the ECPSSR model with exact limits of integration (eCPSSR) and related corrections. These include the electron capture by the incoming ion and multiple ionizations of higher shells. Data from this work were contrasted with previously published L X-ray production cross sections for {sup 14}N{sup 2+} ion impact. As with other ions, a universal behavior is found when L{sub α} and L{sub γ} X-ray production cross sections are plotted as a function of reduced velocity parameters. The agreement with theoretical predictions was very good when the corrections were applied to the eCPSSR model.

Gravitational collapse of a cylindrical null shell in vacuum

Directory of Open Access Journals (Sweden)

S. Khakshournia

2008-03-01

Full Text Available   Barrabès-Israel null shell formalism is used to study the gravitational collapse of a thin cylindrical null shell in vacuum. In general the lightlike matter shell whose history coincides with a null hypersurface is characterized by a surface energy density. In addition, a gravitational impulsive wave is present on this null hypersurface whose generators admit both the shear and expansion. In the case of imposing the cylindrical flatness the surface energy-momentum tensor of the matter shell on the null hypersurface vanishes and the null hyper- surface is just the history of the gravitational wave .

Scanning the parameter space of collapsing rotating thin shells

Science.gov (United States)

Rocha, Jorge V.; Santarelli, Raphael

2018-06-01

We present results of a comprehensive study of collapsing and bouncing thin shells with rotation, framing it in the context of the weak cosmic censorship conjecture. The analysis is based on a formalism developed specifically for higher odd dimensions that is able to describe the dynamics of collapsing rotating shells exactly. We analyse and classify a plethora of shell trajectories in asymptotically flat spacetimes. The parameters varied include the shell’s mass and angular momentum, its radial velocity at infinity, the (linear) equation-of-state parameter and the spacetime dimensionality. We find that plunges of rotating shells into black holes never produce naked singularities, as long as the matter shell obeys the weak energy condition, and so respects cosmic censorship. This applies to collapses of dust shells starting from rest or with a finite velocity at infinity. Not even shells with a negative isotropic pressure component (i.e. tension) lead to the formation of naked singularities, as long as the weak energy condition is satisfied. Endowing the shells with a positive isotropic pressure component allows for the existence of bouncing trajectories satisfying the dominant energy condition and fully contained outside rotating black holes. Otherwise any turning point occurs always inside the horizon. These results are based on strong numerical evidence from scans of numerous sections in the large parameter space available to these collapsing shells. The generalisation of the radial equation of motion to a polytropic equation-of-state for the matter shell is also included in an appendix.

Towards a shell-model description of intruder states and the onset of deformation

International Nuclear Information System (INIS)

Heyde, K.; Van Isacker, P.; Casten, R.F.; Wood, J.L.

1985-01-01

Basing on the nuclear shell-model and concentrating on the monopole, pairing and quadrupole corrections originating from the nucleon-nucleon force, both the appearance of low-lying 0 + intruder states near major closed shells (Z = 50, 82) and sub-shell regions (Z = 40, 64) can be described. Moreover, a number of new facets related to the study of intruder states are presented. 19 refs., 3 figs

Horizon shells and BMS-like soldering transformations

Energy Technology Data Exchange (ETDEWEB)

Blau, Matthias [Albert Einstein Center for Fundamental Physics,Institute for Theoretical Physics, University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland); O’Loughlin, Martin [University of Nova Gorica,Vipavska 13, 5000 Nova Gorica (Slovenia)

2016-03-07

We revisit the theory of null shells in general relativity, with a particular emphasis on null shells placed at horizons of black holes. We study in detail the considerable freedom that is available in the case that one solders two metrics together across null hypersurfaces (such as Killing horizons) for which the induced metric is invariant under translations along the null generators. In this case the group of soldering transformations turns out to be infinite dimensional, and these solderings create non-trivial horizon shells containing both massless matter and impulsive gravitational wave components. We also rephrase this result in the language of Carrollian symmetry groups. To illustrate this phenomenon we discuss in detail the example of shells on the horizon of the Schwarzschild black hole (with equal interior and exterior mass), uncovering a rich classical structure at the horizon and deriving an explicit expression for the general horizon shell energy-momentum tensor. In the special case of BMS-like soldering supertranslations we find a conserved shell-energy that is strikingly similar to the standard expression for asymptotic BMS supertranslation charges, suggesting a direct relation between the physical properties of these horizon shells and the recently proposed BMS supertranslation hair of a black hole.

Molecular effects in carbon K-shell Auger-electron production by 0.6-2.0 MeV protons and extraction of an atomic cross section

International Nuclear Information System (INIS)

McDaniel, F.D.; Lapicki, G.

1987-01-01

Carbon K-shell Auger-electron production cross sections are reported for 0.6-2.0 MeV protons incident on CH 4 (methane), C 2 H 2 (acetylene), C 2 H 4 (ethylene), C 2 H 6 (ethane), n-C 4 H 10 (normal butane), i-C 4 H 10 (isobutane), C 6 H 6 (benzene), CO (carbon monoxide), and CO 2 (carbon dioxide). A constant-energy mode 45 0 parallel-plate electrostatic analyzer was used for detection of Auger electrons. The carbon KLL Auger-electron cross sections for all molecules were found to be lower than that found for CH 4 by 9-23%. All carbon KLL Auger-electron data could be brought into agreement when corrected for the chemical shift of the carbon K-shell binding energy in molecules and for intramolecular scattering. KLL Auger-electron production cross sections are compared to first Born and ECPSSR theories and show good agreement with both after the chemical shift of the carbon K-shell binding energy in molecules and the effects of intramolecular scattering are considered. (orig.)

One-loop renormalization and the properties of radiative corrections in the Fried-Yennie gauge

International Nuclear Information System (INIS)

Karshenbojm, S.G.; Shelyuto, V.A.; Ehjdes, M.I.

1988-01-01

One-loop radiative corrections in the Fried-Yennie gauge are investigated. It is shown that the usual on-mass-shell subtraction may be performed in this gauge without use of the infrared photon mass. The behaviour of the diagrams with corrections near the mass-shell is explored, this behaviour turns out to be in the Freid-Yennie gauge milder than in any other gauge and milder than the behaviour of the corresponding graphs without radiative corrections

QED corrections to the 4p-4d transition energies of copperlike heavy ions

International Nuclear Information System (INIS)

Chen, M. H.; Cheng, K. T.; Johnson, W. R.; Sapirstein, J.

2006-01-01

Quantum electrodynamic (QED) corrections to 4p-4d transition energies of several copperlike ions with Z=70-92 are calculated nonperturbatively in strong external fields to all orders in binding corrections. Dirac-Kohn-Sham potentials are used to account for screening and core-relaxation effects. For the 4p 1/2 -4d 3/2 transition in copperlike bismuth, thorium, and uranium, results are in good agreement with empirical QED corrections deduced from differences between transition energies obtained from recent high-precision electron-beam ion-trap measurements and those calculated with the relativistic many-body perturbation theory (RMBPT). These comparisons provide sensitive tests of QED corrections for high-angular-momentum states in many-electron heavy ions and illustrate the importance of core-relaxation corrections. Comparisons are also made with other theories and with experiments on the 4s-4p transition energies of high-Z Cu-like ions as accuracy checks of the present RMBPT and QED calculations

Self-template synthesis of double shelled ZnS-NiS1.97 hollow spheres for electrochemical energy storage

Science.gov (United States)

Wei, Chengzhen; Ru, Qinglong; Kang, Xiaoting; Hou, Haiyan; Cheng, Cheng; Zhang, Daojun

2018-03-01

In this work, double shelled ZnS-NiS1.97 hollow spheres have been achieved via a simple self-template route, which involves the synthesis of Zn-Ni solid spheres precursors as the self-template and then transformation into double shelled ZnS-NiS1.97 hollow spheres by sulfidation treatment. The as-prepared double shelled ZnS-NiS1.97 hollow spheres possess a high surface area (105.26 m2 g-1) and porous structures. Benefiting from the combined characteristics of novel structures, multi-component, high surface area and porous. When applied as electrode materials for supercapacitors, the double shelled ZnS-NiS1.97hollow spheres deliver a large specific capacitance of 696.8C g-1 at 5.0 A g-1 and a remarkable long lifespan cycling stability (less 5.5% loss after 6000 cycles). Moreover, an asymmetric supercapacitor (ASC) was assembled by utilizing ZnS-NiS1.97 (positive electrode) and activated carbon (negative electrode) as electrode materials. The as-assembled device possesses an energy density of 36 W h kg-1, which can be yet retained 25.6 W h kg-1 even at a power density of 2173.8 W Kg-1, indicating its promising applications in electrochemical energy storage. More importantly, the self-template route is a simple and versatile strategy for the preparation of metal sulfides electrode materials with desired structures, chemical compositions and electrochemical performances.

Shell model description of Ge isotopes

International Nuclear Information System (INIS)

Hirsch, J G; Srivastava, P C

2012-01-01

A shell model study of the low energy region of the spectra in Ge isotopes for 38 ≤ N ≤ 50 is presented, analyzing the excitation energies, quadrupole moments, B(E2) values and occupation numbers. The theoretical results have been compared with the available experimental data. The shell model calculations have been performed employing three different effective interactions and valence spaces. We have used two effective shell model interactions, JUN45 and jj44b, for the valence space f 5/2 pg 9/2 without truncation. To include the proton subshell f 7/2 in valence space we have employed the fpg effective interaction due to Sorlin et al., with 48 Ca as a core and a truncation in the number of excited particles.

Atomistic tight-binding theory of excitonic splitting energies in CdX(X = Se, S and Te)/ZnS core/shell nanocrystals

Science.gov (United States)

Sukkabot, Worasak; Pinsook, Udomsilp

2017-01-01

Using the atomistic tight-binding theory (TB) and a configuration interaction description (CI), we numerically compute the excitonic splitting of CdX(X = Se, S and Te)/ZnS core/shell nanocrystals with the objective to explain how types of the core materials and growth shell thickness can provide the detailed manipulation of the dark-dark (DD), dark-bright (DB) and bright-bright (BB) excitonic splitting, beneficial for the active application of quantum information. To analyze the splitting of the excitonic states, the optical band gaps, ground-state wave function overlaps and atomistic electron-hole interactions tend to be numerically demonstrated. Based on the atomistic computations, the single-particle and excitonic gaps are mainly reduced with the increasing ZnS shell thickness owing to the quantum confinement. In the range of the higher to lower energies, the order of the single-particle gaps is CdSe/ZnS, CdS/ZnS and CdTe/ZnS core/shell nanocrystals, while one of the excitonic gaps is CdS/ZnS, CdSe/ZnS and CdTe/ZnS core/shell nanocrystals because of the atomistic electron-hole interaction. The strongest electron-hole interactions are mainly observed in CdSe/ZnS core/shell nanocrystals. In addition, the computational results underline that the energies of the dark-dark (DD), dark-bright (DB) and bright-bright (BB) excitonic splitting are generally reduced with the increasing ZnS growth shell thickness as described by the trend of the electron-hole exchange interaction. The high-to-low splitting of the excitonic states is demonstrated in CdSe/ZnS, CdTe/ZnS and CdS/ZnS core/shell nanocrystals because of the fashion in the electron-hole exchange interaction and overlaps of the electron-hole wave functions. As the resulting calculations, it is expected that CdS/ZnS core/shell nanocrystals are the best candidates to be the source of entangled photons. Finally, the comprehensive information on the excitonic splitting can enable the use of suitable core/shell

Stable Dyonic Thin-Shell Wormholes in Low-Energy String Theory

Directory of Open Access Journals (Sweden)

Ali Övgün

2017-01-01

Full Text Available Considerable attention has been devoted to the wormhole physics in the past 30 years by exploring the possibilities of finding traversable wormholes without the need for exotic matter. In particular, the thin-shell wormhole formalism has been widely investigated by exploiting the cut-and-paste technique to merge two space-time regions and to research the stability of these wormholes developed by Visser. This method helps us to minimize the amount of the exotic matter. In this paper, we construct a four-dimensional, spherically symmetric, dyonic thin-shell wormhole with electric charge Q, magnetic charge P, and dilaton charge Σ, in the context of Einstein-Maxwell-dilaton theory. We have applied Darmois-Israel formalism and the cut-and-paste method by joining together two identical space-time solutions. We carry out the dyonic thin-shell wormhole stability analyses by using a linear barotropic gas, Chaplygin gas, and logarithmic gas for the exotic matter. It is shown that, by choosing suitable parameter values as well as equation of state parameter, under specific conditions, we obtain a stable dyonic thin-shell wormhole solution. Finally, we argue that the stability domain of the dyonic thin-shell wormhole can be increased in terms of electric charge, magnetic charge, and dilaton charge.

An extension of the fenske-hall LCAO method for approximate calculations of inner-shell binding energies of molecules

Science.gov (United States)

Zwanziger, Ch.; Reinhold, J.

1980-02-01

The approximate LCAO MO method of Fenske and Hall has been extended to an all-election method allowing the calculation of inner-shell binding energies of molecules and their chemical shifts. Preliminary results are given.

Self-consistency corrections in effective-interaction calculations

International Nuclear Information System (INIS)

Starkand, Y.; Kirson, M.W.

1975-01-01

Large-matrix extended-shell-model calculations are used to compute self-consistency corrections to the effective interaction and to the linked-cluster effective interaction. The corrections are found to be numerically significant and to affect the rate of convergence of the corresponding perturbation series. The influence of various partial corrections is tested. It is concluded that self-consistency is an important effect in determining the effective interaction and improving the rate of convergence. (author)

Meson-exchange-current corrections to magnetic moments in quantum hadrodynamics

International Nuclear Information System (INIS)

Morse, T.M.

1990-01-01

Corrections to the magnetic moments of the non-relativistic shell model (Schmidt lines) have a long history. In the early fifties calculations of pion exchange and core polarization contributions to nuclear magnetic moments were initiated. These calculations matured by the early eighties to include other mesons and the delta isobar. Relativistic nuclear shell model calculations are relatively recent. Meson exchange and the delta isobar current contributions to the magnetic moments of the relativistic shell model have remained largely unexplored. The disagreement between the valence values of spherical relativistic mean-field models and experiment was a major problem with early (1975-1985) quantum hydrodynamics (QHD) calculations of magnetic moments. Core polarization calculations (1986-1988) have been found to resolve the large discrepancy, predicting isoscalar magnetic moments to within typically five percent of experiment. The isovector magnetic moments, however, are about twice as far from experiment with an average discrepancy of about ten percent. The pion, being the lightest of the mesons, has historically been expected to dominate isovector corrections. Because this has been found to be true in non-relativistic calculations, the author calculated the pion corrections in the framework of QHD. The seagull and in-flight pion exchange current diagram corrections to the magnetic moments of eight finite nuclei (plus or minus one valence nucleon from the magic A = 16 and A = 40 doubly closed shell systems) are calculated in the framework of QHD, and compared with earlier non-relativistic calculations and experiment

Deformation Behavior of Press Formed Shell by Indentation and Its Numerical Simulation

Directory of Open Access Journals (Sweden)

Minoru Yamashita

2015-01-01

Full Text Available Deformation behavior and energy absorbing performance of the press formed aluminum alloy A5052 shells were investigated to obtain the basic information regarding the mutual effect of the shell shape and the indentor. Flat top and hemispherical shells were indented by the flat- or hemispherical-headed indentor. Indentation force in the rising stage was sharper for both shell shapes when the flat indentor was used. Remarkable force increase due to high in-plane compressive stress arisen by the appropriate tool constraint was observed in the early indentation stage, where the hemispherical shell was deformed with the flat-headed indentor. This aspect is preferable for energy absorption performance per unit mass. Less fluctuation in indentation force was achieved in the combination of the hemispherical shell and similar shaped indentor. The consumed energy in the travel length of the indentor equal to the shell height was evaluated. The increase ratio of the energy is prominent when the hemispherical indentor is replaced by a flat-headed one in both shell shapes. Finite element simulation was also conducted. Deformation behaviors were successfully predicted when the kinematic hardening plasticity was introduced in the material model.

Dyson shells: a retrospective

Science.gov (United States)

Bradbury, Robert J.

2001-08-01

More than 40 years have passed since Freeman Dyson suggested that advanced technological civilizations are likely to dismantle planets in their solar systems to harvest all of the energy their stars wastefully radiate into space. Clearly this was an idea that was ahead of its time. Since that time, dozens of SETI searches have been conducted and almost all of them have focused their attention on stars which by definition cannot be the advanced civilizations that Dyson envisioned. I will review the data that created the confusion between Dyson spheres and Dyson shells. The sources that disprove Dyson spheres while still allowing Dyson shells will be discussed. The use of outmoded ideas that have biased the few searches for Dyson Shells that have occurred will be pointed out. An update of the concept of Dyson shells to include our current knowledge of biotechnology, nanotechnology and computer science will be explored. Finally, an approach to setting limits on the abundance of Dyson shells in our galaxy using existing optical astronomical data and future optical satellites will be proposed.

A Lagrangian framework for deriving triples and quadruples corrections to the CCSD energy

DEFF Research Database (Denmark)

Eriksen, Janus Juul; Kristensen, Kasper; Kjærgaard, Thomas

2014-01-01

Using the coupled cluster Lagrangian technique, we have determined perturbative corrections to the coupled cluster singles and doubles (CCSD) energy that converge towards the coupled cluster singles, doubles, and triples (CCSDT) and coupled cluster singles, doubles, triples, and quadruples (CCSDTQ......) energies, considering the CCSD state as the unperturbed reference state and the fluctua- tion potential as the perturbation. Since the Lagrangian technique is utilized, the energy corrections satisfy Wigner’s 2n + 1 rule for the cluster amplitudes and the 2n + 2 rule for the Lagrange multi- pliers...

On the shell model connection of the cluster model

International Nuclear Information System (INIS)

Cseh, J.; Levai, G.; Kato, K.

2000-01-01

Complete text of publication follows. The interrelation of basic nuclear structure models is a longstanding problem. The connection between the spherical shell model and the quadrupole collective model has been studied extensively, and symmetry considerations proved to be especially useful in this respect. A collective band was interpreted in the shell model language long ago as a set of states (of the valence nucleons) with a specific SU(3) symmetry. Furthermore, the energies of these rotational states are obtained to a good approximation as eigenvalues of an SU(3) dynamically symmetric shell model Hamiltonian. On the other hand the relation of the shell model and cluster model is less well explored. The connection of the harmonic oscillator (i.e. SU(3)) bases of the two approaches is known, but it was established only for the unrealistic harmonic oscillator interactions. Here we investigate the question: Can an SU(3) dynamically symmetric interaction provide a similar connection between the spherical shell model and the cluster model, like the one between the shell and collective models? In other words: whether or not the energy of the states of the cluster bands, defined by a specific SU(3) symmetries, can be obtained from a shell model Hamiltonian (with SU(3) dynamical symmetry). We carried out calculations within the framework of the semimicroscopic algebraic cluster model, in which not only the cluster model space is obtained from the full shell model space by an SU(3) symmetry-dictated truncation, but SU(3) dynamically symmetric interactions are also applied. Actually, Hamiltonians of this kind proved to be successful in describing the gross features of cluster states in a wide energy range. The novel feature of the present work is that we apply exclusively shell model interactions. The energies obtained from such a Hamiltonian for several bands of the ( 12 C, 14 C, 16 O, 20 Ne, 40 Ca) + α systems turn out to be in good agreement with the experimental

Energy dependence corrections to MOSFET dosimetric sensitivity

International Nuclear Information System (INIS)

Cheung, T.; Yu, P.K.N.; Butson, M.J.; Illawarra Cancer Care Centre, Crown St, Wollongong

2009-01-01

Metal Oxide Semiconductor Field Effect Transistors (MOSFET's) are dosimeters which are now frequently utilized in radiotherapy treatment applications. An improved MOSFET, clinical semiconductor dosimetry system (CSDS) which utilizes improved packaging for the MOSFET device has been studied for energy dependence of sensitivity to x-ray radiation measurement. Energy dependence from 50 kVp to 10 MV x-rays has been studied and found to vary by up to a factor of 3.2 with 75 kVp producing the highest sensitivity response. The detectors average life span in high sensitivity mode is energy related and ranges from approximately 100 Gy for 75 kVp x-rays to approximately 300 Gy at 6MV x-ray energy. The MOSFET detector has also been studied for sensitivity variations with integrated dose history. It was found to become less sensitive to radiation with age and the magnitude of this effect is dependant on radiation energy with lower energies producing a larger sensitivity reduction with integrated dose. The reduction in sensitivity is however approximated reproducibly by a slightly non linear, second order polynomial function allowing corrections to be made to reading to account for this effect to provide more accurate dose assessments both in phantom and in-vivo.

Energy dependence corrections to MOSFET dosimetric sensitivity.

Science.gov (United States)

Cheung, T; Butson, M J; Yu, P K N

2009-03-01

Metal Oxide Semiconductor Field Effect Transistors (MOSFET's) are dosimeters which are now frequently utilized in radiotherapy treatment applications. An improved MOSFET, clinical semiconductor dosimetry system (CSDS) which utilizes improved packaging for the MOSFET device has been studied for energy dependence of sensitivity to x-ray radiation measurement. Energy dependence from 50 kVp to 10 MV x-rays has been studied and found to vary by up to a factor of 3.2 with 75 kVp producing the highest sensitivity response. The detectors average life span in high sensitivity mode is energy related and ranges from approximately 100 Gy for 75 kVp x-rays to approximately 300 Gy at 6 MV x-ray energy. The MOSFET detector has also been studied for sensitivity variations with integrated dose history. It was found to become less sensitive to radiation with age and the magnitude of this effect is dependant on radiation energy with lower energies producing a larger sensitivity reduction with integrated dose. The reduction in sensitivity is however approximated reproducibly by a slightly non linear, second order polynomial function allowing corrections to be made to readings to account for this effect to provide more accurate dose assessments both in phantom and in-vivo.

The low-energy theorem of pion photoproduction using the Skyrme model

International Nuclear Information System (INIS)

Ikehashi, T.; Ohta, K.

1995-01-01

We reassess the validity of the current-algebra based low-energy theorem of pion photoproduction on the nucleon using the Skyrme model. We find that one of the off-shell electromagnetic form factors of the nucleon exhibits infrared divergence in the chiral limit. This contribution introduces an additional term to the threshold amplitude predicted by the low-energy theorem. The emergence of the additional term indicates an unavoidable necessity of off-shell form factors in deriving the low-energy theorem. In the case of neutral pion production, the new contribution to the threshold amplitude is found to be comparable in magnitude to the low-energy theorem's prediction and has the opposite sign. In the charged pion production channels, the correction to the theorem is shown to be relatively small. (orig.)

Atomistic tight-binding computations of the structural and optical properties of CdTe/CdX (X=S and Se)/ZnS core/shell/shell nanocrystals

Science.gov (United States)

Sukkabot, Worasak

2018-05-01

A study of CdTe/CdX (X=S and Se)/ZnS core/shell/shell nanocrystals is carried out using atomistic tight-binding theory and the configuration interaction method to provide information for applications in bioimaging, biolabeling, display devices and near-infrared electronic instruments. The calculations yield the dependences of the internal and external passivated shells on the natural behaviours of CdTe/CdX (X=S and Se)/ZnS core/shell/shell nanocrystals. The reduction of the optical band gaps is observed with increasing numbers of monolayers in the external ZnS shell due to quantum confinement. Interestingly, the optical band gaps of CdTe/CdS/ZnS core/shell/shell nanocrystals are greater than those of CdTe/CdSe/ZnS core/shell/shell nanocrystals. In the presence of an external ZnS-coated shell, electron-hole wave function overlaps, oscillation strengths, ground-state exchange energies and Stokes shift are improved, whereas ground-state coulomb energies and fine-structure splitting are reduced. The oscillation strengths, Stokes shift and fine-structure splitting are reduced with the increase in external ZnS shell thickness. The oscillation strengths, Stokes shift and fine-structure splitting of CdTe/CdS/ZnS core/shell/shell nanocrystals are larger than those of CdTe/CdSe/ZnS core/shell/shell nanocrystals. Reduction of the atomistic electron-hole interactions is observed with increasing external ZnS shell size. The strong electron-hole interactions are more probed in CdTe/CdS/ZnS core/shell/shell nanocrystals than in CdTe/CdSe/ZnS core/shell/shell nanocrystals.

Genomics on the Half Shell: So, What do Oysters Have to do with Energy? (2010 JGI User Meeting)

Energy Technology Data Exchange (ETDEWEB)

Hedgecock, Dennis

2010-03-24

Dennis Hedgecock from the University of Southern California answers the question, "Genomics on the Half Shell: So, What Do Oysters Have to Do with Energy?" on March 24, 2010 at the 5th Annual DOE JGI User Meeting.

Quantum-mechanical few-body scattering equations with half-on-shell energy-independent subsystem input

International Nuclear Information System (INIS)

Zeiger, E.M.

1978-01-01

New equations are presented for three- and four-body scattering, within the context of nonrelativistic quantum mechanics and a Hamiltonian scattering theory. For the three-body case Faddeev-type equations are presented which, although obtained from the rigorous Faddeev theory, only require two-body bound state wave functions and half-off-shell transition amplitudes as input. In addition, their effective potentials are independent of the three-body energy, and can easily be made real after an angular momentum decomposition. The equations are formulated in terms of physical transition amplitudes for three-body processes, except that in the breakup case the partial-wave amplitudes differ from the corresponding full amplitudes by a Watson final-state-interaction factor. Also presented are new equations for four-body scattering, obtained by generalizing our three-body formalism to the four-body case. These equations, although equivalent to those of Faddeev--Yakubovskii, are expressed in terms of singularity-free transition amplitudes, and their energy-independent effective potentials require only half-on-shell subsystem transition amplitudes (and bound state wave functions) as input. However, due to the detailed index structure of the Faddeev--Yakubovskii formalsim, the result of the generalization is considerably more complicated than in the three-body case

Development of Mortar Simulator with Shell-In-Shell System – Problem of External Ballistics

Directory of Open Access Journals (Sweden)

A. Fedaravicius

2007-01-01

Full Text Available The shell-in-shell system used in the mortar simulator raises a number of non-standard technical and computational problems starting from the requirement to distribute the propelling blast energy between the warhead and the ballistic barrel, finishing with the requirement that the length of warhead's flight path must be scaled to combat shell firing tables. The design problem of the simulator is split into two parts – the problem of external ballistics where the initial velocities of the warhead must be determined, and the problem of internal ballistics – where the design of the cartridge and the ballistic barrel must be performed.

Inner-shell/subshell photoionization cross section measurements using a gamma excited variable energy X-ray source

Energy Technology Data Exchange (ETDEWEB)

Sood, B S; Allawadhi, K L; Arora, S K [Punjabi Univ., Patiala (India). Nuclear Science Labs.

1982-02-15

The method developed for the determination of K/L shell photoionization cross sections in various elements, 39 <= Z <= 92, in the characteristic X-ray energy region using a gamma excited variable energy X-ray source has been used for the measurement of Lsub(III) subshell photoionization cross section in Pb, Th and U. The measurements are made at the K X-ray energies of Rb, Nb and Mo, since these are able to excite selectively the Lsub(III) subshells of Pb, Th and U, respectively. The results, when compared with theoretical calculations of Scofield, are found to agree within the uncertainties of determination.

On the gluonic correction to lepton-pair decays in a relativistic quarkonium model

International Nuclear Information System (INIS)

Ito, Hitoshi

1987-01-01

The gluonic correction to the leptonic decay of the heavy vector meson is investigated by using the perturbation theory to the order α s . The on-mass-shell approximation is assumed for the constituent quarks so that we assure the gauge independence of the correction. The decay rates in the model based on the Bethe-Salpeter equation are also shown, in which the gluonic correction with a high-momentum cutoff is calculated for the off-shell quarks. It is shown that the static approximation to the correction factor (1 - 16α s /3π) is not adequate and the gluonic correction does not suppress but enhance the decay rates of the ground states for the c anti c and b anti b systems. (author)

Fabrication of Foam Shells for ICF Experiments

Science.gov (United States)

Czechowicz, D. G.; Acenas, O.; Flowers, J. S.; Nikroo, A.; Paguio, R. R.; Schroen, D. G.; Streit, J.; Takagi, M.

2004-11-01

The General Atomics/Schafer team has developed processes to fabricate foam shells targets suitable for ICF experiments. The two most common chemical systems used to produce foam shells have been resorcinol-formaldehyde (R/F) aerogel and divinylbenzene (DVB). Spherical targets have been made in the form of shells and beads having diameters ranging from approximately 0.5 mm to 4.0 mm, and having densities from approximately 100 mg/cc to 250 mg/cc. The work on R/F foam shells has been concentrated on 1) shell fabrication process improvement to obtain high yields ( ˜25%) and 2) depositing a reliable permeation barrier to provide shells for ongoing direct drive experiments at LLE. Development of divinylbenzene foam shells has been mainly directed towards Inertial Fusion Energy applications (at densities as low as 30 mg/cc) and recently for shells for experiments at LLE. Details of the relevant metrology and properties of these foams as well as the range of targets currently available will be discussed.

Synthesis and Performances of Phase Change Microcapsules with a Polymer/Diatomite Hybrid Shell for Thermal Energy Storage

Directory of Open Access Journals (Sweden)

Yanli Sun

2018-05-01

Full Text Available The mechanical behavior of phase-change microcapsules (microPCMs is of vital significance for practical applications in thermal energy storage. Hence, a new type of microPCMs based on an n-octadecane (C18 core and a melamine-urea-formaldehyde (MUF/diatomite hybrid shell was developed through in situ polymerization. Based on SEM micrographs, most microPCMs exhibited a nearly spherical and smooth microstructure, with broadened particle size distributions. It was confirmed by Fourier transform infrared (FTIR that successful polymerization of diatomite into the microPCMs occurred, and that additional diatomite had no effect on the core coated by the shell. In addition, the results of the differential scanning calorimeter (DSC and Atomic Force Microscopy (AFM demonstrated that the mechanical properties of the microPCMs were remarkably improved by the addition of a moderate amount of diatomite, but that the heat enthalpy and encapsulated efficiency (η decreased slightly. The incorporation of 2 wt % diatomite resulted in the average Young’s modulus of microPCMs, which was 1.64 times greater than those of microPCMs without diatomite. Furthermore, the melting and crystallization enthalpies and the encapsulated efficiency of the microPCMs were as high as 237.6 J/g, 234.4 J/g and 77.90%, respectively. The microPCMs with a polymer/diatomite hybrid shell may become the potential materials in the application of thermal energy storage.

Creep buckling of shell structures

International Nuclear Information System (INIS)

Miyazaki, Noriyuki; Hagihara, Seiya

2015-01-01

The present article contains a review of the literatures on the creep buckling of shell structures published from late 1950's to recent years. In this article, the creep buckling studies on circular cylindrical shells, spherical shells, partial cylindrical shells and other shells are reviewed in addition to creep buckling criteria. Creep buckling is categorized into two types. One is the creep buckling due to quasi-static instability, in which the critical time for creep buckling is determined by tracing a creep deformation versus time curve. The other is the creep buckling due to kinetic instability, in which the critical time can be determined by examining the shape of total potential energy in the vicinity of a quasi-static equilibrium state. Bifurcation buckling and snap-through buckling during creep deformation belong to this type of creep buckling. A few detailed descriptions are given to the bifurcation and snap-through type of creep buckling based on the present authors' works. (author)

The congruence energy: A contribution to nuclear masses and deformation energies

International Nuclear Information System (INIS)

Myers, W.D.; Swiatecki, W.J.

1995-06-01

The difference between measured binding energies and those calculated using a shell- and pairing-corrected Thomas-Fermi model can be described approximately by C(I) = -10exp(-4.2|I|) MeV. The authors' interpretation of this extra binding is in terms of the granularity of quantal nucleonic density distributions, which leads to a stronger interaction for a neutron and proton with congruent nodal structures of their wave functions. The predicted doubling of this congruence energy in fission is supported by an analysis of measured fission barriers and by a study of wave functions in a dividing Hill-Wheeler box potential. A semi-empirical formula for the shape-dependent congruence energy is described

Domain shape dependence of semiclassical corrections to energy

International Nuclear Information System (INIS)

Kwiatkowski, Grzegorz

2017-01-01

Stationary solution of a one-dimensional sine-Gordon system is embedded in a multidimensional theory with an explicitly finite domain in the added spatial dimensions. Semiclassical corrections to energy are calculated for a static kink solution with emphasis on the impact of the scale of the domain as well as the choice of boundary conditions on the results for a rectangular cross-section. (paper)

Synthesis of Aqueous CdTe/CdS/ZnS Core/shell/shell Quantum Dots by a Chemical Aerosol Flow Method

Directory of Open Access Journals (Sweden)

Chen Dong

2009-01-01

Full Text Available Abstract This work described a continuous method to synthesize CdTe/CdS/ZnS core/shell/shell quantum dots. In an integrated system by flawlessly combining the chemical aerosol flow system working at high temperature (200–300°C to generate CdTe/CdS intermediate products and an additional heat-up setup at relatively low temperature to overcoat the ZnS shells, the CdTe/CdS/ZnS multishell structures were realized. The as-synthesized CdTe/CdS/ZnS core/shell/shell quantum dots are characterized by photoluminescence spectra, X-ray diffraction (XRD, energy-dispersive X-ray spectra (EDS, transmission electron microscopy (TEM, and high-resolution transmission electron microscopy (HRTEM. Fluorescence and XRD results confirm that the obtained quantum dots have a core/shell/shell structure. It shows the highest quantum yield above 45% when compared to the rhodamine 6G. The core/shell/shell QDs were more stable via the oxidation experiment by H2O2.

Designing of an artificial light energy converter in the form of short-chain dyad when combined with core-shell gold/silver nanocomposites.

Science.gov (United States)

Dutta Pal, Gopa; Paul, Somnath; Bardhan, Munmun; De, Asish; Ganguly, Tapan

2017-06-05

UV-vis absorption, steady state and time resolved fluorescence and absorption spectroscopic investigations demonstrate that the short chain dyad MNTMA when combined with gold-silver core-shell (Au@Ag) nanocomposite , forms elongated conformers in the excited state whereas for the dyad - Ag (spherical) system the majority of dyads remains in a folded conformation. In the dyad-core-shell nanocomposite system, energy wasting charge recombination rate slows down primarily due to elongated conformation and thus it may be anticipated that this hybrid nanocomposite system may serve as a better light energy conversion device. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of Coulomb repulsion in the inner-shell ionization cross-section by protons, deuterons and alpha-particles

International Nuclear Information System (INIS)

Magno, C.; Milazzo, M.; Pizzi, C.; Porro, F.; Rota, A.; Riccobono, G.

1979-01-01

A critical survey has been made of the currently accepted BEA theory for inner-shell atomic-ionization processes. This review has led to the introduction of an effective ion energy which accounts for the slowing-down of the ion in the nuclear Coulomb field. The effect of the ion deflection, also due to the nuclear Coulomb field, is analyzed. Relativistic effects in the collision of ions with K-shell electrons have been taken into account. A tentative qualitative explanation for the experimentally observed nonexistence of a threshold energy for ionization is given in the framework of the BEA theory. Ionization cross-sections for Rb, Sr, Zr, Cd, In, Sb, W by protons in the energy range from 500 keV to 3 MeV have been measured. Also measurements of ionization cross-sections by deuterons in the energy range from 800 keV to 2.6 MeV on Rb, Sr, Zr, Cd, Sb and by He ions in the energy range from 1.4 MeV to 2.8 MeV on Cd and Sb have been performed. Results are compared with those of other authors and in the context of the corrections introduced in the BEA theory. (author)

A solar-thermal energy harvesting scheme: enhanced heat capacity of molten HITEC salt mixed with Sn/SiO(x) core-shell nanoparticles.

Science.gov (United States)

Lai, Chih-Chung; Chang, Wen-Chih; Hu, Wen-Liang; Wang, Zhiming M; Lu, Ming-Chang; Chueh, Yu-Lun

2014-05-07

We demonstrated enhanced solar-thermal storage by releasing the latent heat of Sn/SiO(x) core-shell nanoparticles (NPs) embedded in a eutectic salt. The microstructures and chemical compositions of Sn/SiO(x) core-shell NPs were characterized. In situ heating XRD provides dynamic crystalline information about the Sn/SiO(x) core-shell NPs during cyclic heating processes. The latent heat of ∼29 J g(-1) for Sn/SiO(x) core-shell NPs was measured, and 30% enhanced heat capacity was achieved from 1.57 to 2.03 J g(-1) K(-1) for the HITEC solar salt without and with, respectively, a mixture of 5% Sn/SiO(x) core-shell NPs. In addition, an endurance cycle test was performed to prove a stable operation in practical applications. The approach provides a method to enhance energy storage in solar-thermal power plants.

A study of the Gaussian overlap approach in the two-center shell model

International Nuclear Information System (INIS)

Reinhard, P.-G.

1976-01-01

The Gaussian overlap approach (GOA) to the generator coordinate method (GCM) is carried through up to fourth order in the derivatives. By diagonalizing the norm overlap, a collective Schroedinger equation is obtained. The potential therein contains the usual potential energy surface (PES) plus correction terms, which subtract the zero-point energies (ZPE) is the PES. The formalism is applied to BCS states obtained from a two-center shell model (TCSM). To understand the crucial role of the pairing contributions in the GOA a schematic picture, the multi-level model, is constructed. An explicit numerical study of the convergence of the GOA is given for the TCSM, with the result that the GOA seems to be justified for medium and heavy nuclei but critical for light nuclei. (Auth.)

On the shell-model-connection of the cluster model

International Nuclear Information System (INIS)

Cseh, J.

2000-01-01

Complete text of publication follows. The interrelation of basic nuclear structure models is a longstanding problem. The connection between the spherical shell model and the quadrupole collective model has been studied extensively, and symmetry considerations proved to be especially useful in this respect. A collective band was interpreted in the shell model language long ago [1] as a set of states (of the valence nucleons) with a specific SU(3) symmetry. Furthermore, the energies of these rotational states are obtained to a good approximation as eigenvalues of an SU(3) dynamically symmetric shell model Hamiltonian. On the other hand the relation of the shell model and cluster model is less well explored. The connection of the harmonic oscillator (i.e. SU(3)) bases of the two approaches is known [2] but it was established only for the unrealistic harmonic oscillator interactions. Here we investigate the question: Can an SU(3) dynamically symmetric interaction provide a similar connection between the spherical shell model and the cluster model, like the one between the shell and collective models? In other words: whether or not the energy of the states of the cluster bands, defined by a specific SU(3) symmetries, can be obtained from a shell model Hamiltonian (with SU(3) dynamical symmetry). We carried out calculations within the framework of the semimicroscopic algebraic cluster model [3,4] in order to find an answer to this question, which seems to be affirmative. In particular, the energies obtained from such a Hamiltonian for several bands of the ( 12 C, 14 C, 16 O, 20 Ne, 40 Ca) + α systems turn out to be in good agreement with the experimental values. The present results show that the simple and transparent SU(3) connection between the spherical shell model and the cluster model is valid not only for the harmonic oscillator interactions, but for much more general (SU(3) dynamically symmetric) Hamiltonians as well, which result in realistic energy spectra. Via

Performance analysis of nanodisk and core/shell/shell-nanowire type III-Nitride heterojunction solar cell for efficient energy harvesting

Science.gov (United States)

Routray, S. R.; Lenka, T. R.

2017-11-01

Now-a-days III-Nitride nanowires with axial (nanodisk) and radial (core/shell/shell-nanowire) junctions are two unique and potential methods for solar energy harvesting adopted by worldwide researchers. In this paper, polarization behavior of GaN/InGaN/GaN junction and its effect on carrier dynamics of nanodisk and CSS-nanowire type solar cells are intensively studied and compared with its planar counterpart by numerical simulations using commercially available Victory TCAD. It is observed that CSS-NW with hexagonal geometrical shapes are robust to detrimental impact of polarization charges and could be good enough to accelerate carrier collection efficiency as compared to nanodisk and planar solar cells. This numerical study provides an innovative aspect of fundamental device physics with respect to polarization charges in CSS-NW and nanodisk type junction towards photovoltaic applications. The internal quantum efficiencies (IQE) are also discussed to evaluate carrier collection mechanisms and recombination losses in each type of junctions of solar cell. Finally, it is interesting to observe a maximum conversion efficiency of 6.46% with 91.6% fill factor from n-GaN/i-In0.1Ga0.9N/p-GaN CSS-nanowire solar cell with an optimized thickness of 180 nm InGaN layer under one Sun AM1.5 illumination.

On-the-energy-shell approximation for the heavy ion couple-channels problems

International Nuclear Information System (INIS)

Carlson, B.V.; Hussein, M.S.

Starting with the coupled channels equations describing multiple Coulomb excitations in heavy ion collisions an approximation scheme is developed based on replacing the channel Green's functions by their on-the-energy shell forms, which permits an exact analytic solution for the scattering matrix. The trivially equivalent Coulomb polarization potential valid for strong coupling and small energy loss in the excitation processes is constructed. This potential is seen to have a very simple r-dependence. A simple formula for the sub-barrier elastic scattering cross section is then derived both by using the WRB approximation and by summing the Born series for the T-matrix. Comparison of the two forms for the elastic cross section shows that they give almost identical numerical results in the small coupling limit only. The results are also compared with the predictions of the Alder-Winther theory. (Author) [pt

Scatter correction method with primary modulator for dual energy digital radiography: a preliminary study

Science.gov (United States)

Jo, Byung-Du; Lee, Young-Jin; Kim, Dae-Hong; Jeon, Pil-Hyun; Kim, Hee-Joung

2014-03-01

In conventional digital radiography (DR) using a dual energy subtraction technique, a significant fraction of the detected photons are scattered within the body, resulting in the scatter component. Scattered radiation can significantly deteriorate image quality in diagnostic X-ray imaging systems. Various methods of scatter correction, including both measurement and non-measurement-based methods have been proposed in the past. Both methods can reduce scatter artifacts in images. However, non-measurement-based methods require a homogeneous object and have insufficient scatter component correction. Therefore, we employed a measurement-based method to correct for the scatter component of inhomogeneous objects from dual energy DR (DEDR) images. We performed a simulation study using a Monte Carlo simulation with a primary modulator, which is a measurement-based method for the DEDR system. The primary modulator, which has a checkerboard pattern, was used to modulate primary radiation. Cylindrical phantoms of variable size were used to quantify imaging performance. For scatter estimation, we used Discrete Fourier Transform filtering. The primary modulation method was evaluated using a cylindrical phantom in the DEDR system. The scatter components were accurately removed using a primary modulator. When the results acquired with scatter correction and without correction were compared, the average contrast-to-noise ratio (CNR) with the correction was 1.35 times higher than that obtained without correction, and the average root mean square error (RMSE) with the correction was 38.00% better than that without correction. In the subtraction study, the average CNR with correction was 2.04 (aluminum subtraction) and 1.38 (polymethyl methacrylate (PMMA) subtraction) times higher than that obtained without the correction. The analysis demonstrated the accuracy of scatter correction and the improvement of image quality using a primary modulator and showed the feasibility of

Static black hole and vacuum energy: thin shell and incompressible fluid

Science.gov (United States)

Ho, Pei-Ming; Matsuo, Yoshinori

2018-03-01

With the back reaction of the vacuum energy-momentum tensor consistently taken into account, we study static spherically symmetric black-hole-like solutions to the semi-classical Einstein equation. The vacuum energy is assumed to be given by that of 2-dimensional massless scalar fields, as a widely used model in the literature for black holes. The solutions have no horizon. Instead, there is a local minimum in the radius. We consider thin shells as well as incompressible fluid as the matter content of the black-hole-like geometry. The geometry has several interesting features due to the back reaction of vacuum energy. In particular, Buchdahl's inequality can be violated without divergence in pressure, even if the surface is below the Schwarzschild radius. At the same time, the surface of the star can not be far below the Schwarzschild radius for a density not much higher than the Planck scale, and the proper distance from its surface to the origin can be very short even for very large Schwarzschild radius. The results also imply that, contrary to the folklore, in principle the Boulware vacuum can be physical for black holes.

Stability of the Regular Hayward Thin-Shell Wormholes

Directory of Open Access Journals (Sweden)

M. Sharif

2016-01-01

Full Text Available The aim of this paper is to construct regular Hayward thin-shell wormholes and analyze their stability. We adopt Israel formalism to calculate surface stresses of the shell and check the null and weak energy conditions for the constructed wormholes. It is found that the stress-energy tensor components violate the null and weak energy conditions leading to the presence of exotic matter at the throat. We analyze the attractive and repulsive characteristics of wormholes corresponding to ar>0 and ar<0, respectively. We also explore stability conditions for the existence of traversable thin-shell wormholes with arbitrarily small amount of fluid describing cosmic expansion. We find that the space-time has nonphysical regions which give rise to event horizon for 0shell wormholes.

Self-consistent EXAFS PDF Projection Method by Matched Correction of Fourier Filter Signal Distortion

International Nuclear Information System (INIS)

Lee, Jay Min; Yang, Dong-Seok

2007-01-01

Inverse problem solving computation was performed for solving PDF (pair distribution function) from simulated data EXAFS based on data FEFF. For a realistic comparison with experimental data, we chose a model of the first sub-shell Mn-0 pair showing the Jahn Teller distortion in crystalline LaMnO3. To restore the Fourier filtering signal distortion, involved in the first sub-shell information isolated from higher shell contents, relevant distortion matching function was computed initially from the proximity model, and iteratively from the prior-guess during consecutive regularization computation. Adaptive computation of EXAFS background correction is an issue of algorithm development, but our preliminary test was performed under the simulated background correction perfectly excluding the higher shell interference. In our numerical result, efficient convergence of iterative solution indicates a self-consistent tendency that a true PDF solution is convinced as a counterpart of genuine chi-data, provided that a background correction function is iteratively solved using an extended algorithm of MEPP (Matched EXAFS PDF Projection) under development

Ni3Si(Al)/a-SiOx core shell nanoparticles: characterization, shell formation, and stability

Science.gov (United States)

Pigozzi, G.; Mukherji, D.; Gilles, R.; Barbier, B.; Kostorz, G.

2006-08-01

We have used an electrochemical selective phase dissolution method to extract nanoprecipitates of the Ni3Si-type intermetallic phase from two-phase Ni-Si and Ni-Si-Al alloys by dissolving the matrix phase. The extracted nanoparticles are characterized by transmission electron microscopy, energy-dispersive x-ray spectrometry, x-ray powder diffraction, and electron powder diffraction. It is found that the Ni3Si-type nanoparticles have a core-shell structure. The core maintains the size, the shape, and the crystal structure of the precipitates that existed in the bulk alloys, while the shell is an amorphous phase, containing only Si and O (SiOx). The shell forms around the precipitates during the extraction process. After annealing the nanoparticles in nitrogen at 700 °C, the tridymite phase recrystallizes within the shell, which remains partially amorphous. In contrast, on annealing in air at 1000 °C, no changes in the composition or the structure of the nanoparticles occur. It is suggested that the shell forms after dealloying of the matrix phase, where Si atoms, the main constituents of the shell, migrate to the surface of the precipitates.

Stiffeners in variational-difference method for calculating shells with complex geometry

Directory of Open Access Journals (Sweden)

Ivanov Vyacheslav Nikolaevich

2014-05-01

Full Text Available We have already considered an introduction of reinforcements in the variational-difference method (VDM of shells analysis with complex shape. At the moment only ribbed shells of revolution and shallow shells can be calculated with the help of developed analytical and finite-difference methods. Ribbed shells of arbitrary shape can be calculated only using the finite element method (FEM. However there are problems, when using FEM, which are absent in finite- and variational-difference methods: rigid body motion; conforming trial functions; parameterization of a surface; independent stress strain state. In this regard stiffeners are entered in VDM. VDM is based on the Lagrange principle - the principle of minimum total potential energy. Stress-strain state of ribs is described by the Kirchhoff-Clebsch theory of curvilinear bars: tension, bending and torsion of ribs are taken into account. Stress-strain state of shells is described by the Kirchhoff-Love theory of thin elastic shells. A position of points of the middle surface is defined by curvilinear orthogonal coordinates α, β. Curved ribs are situated along coordinate lines. Strain energy of ribs is added into the strain energy to account for ribs. A matrix form of strain energy of ribs is formed similar to a matrix form of the strain energy of the shell. A matrix of geometrical characteristics of a rib is formed from components of matrices of geometric characteristics of a shell. A matrix of mechanical characteristics of a rib contains rib’s eccentricity and geometrical characteristics of a rib’s section. Derivatives of displacements in the strain vector are replaced with finite-difference relations after the middle surface of a shell gets covered with a grid (grid lines coincide with the coordinate lines of principal curvatures. By this case the total potential energy functional becomes a function of strain nodal displacements. Partial derivatives of unknown nodal displacements are

Exploring the potential of climate adaptive building shells

NARCIS (Netherlands)

Loonen, R.C.G.M.; Trcka, M.; Hensen, J.L.M.

2011-01-01

Building shells with adaptive, rather than static properties, intuitively offer opportunities for both energy savings and comfort enhancements. Progress in this field is characterized by fragmented developments, and the most effective type of climate adaptive building shell (CABS) behaviour is still

A new aberration-corrected, energy-filtered LEEM/PEEM instrument. I. Principles and design

International Nuclear Information System (INIS)

Tromp, R.M.; Hannon, J.B.; Ellis, A.W.; Wan, W.; Berghaus, A.; Schaff, O.

2010-01-01

We describe a new design for an aberration-corrected low energy electron microscope (LEEM) and photo electron emission microscope (PEEM), equipped with an in-line electron energy filter. The chromatic and spherical aberrations of the objective lens are corrected with an electrostatic electron mirror that provides independent control over the chromatic and spherical aberration coefficients C c and C 3 , as well as the mirror focal length, to match and correct the aberrations of the objective lens. For LEEM (PEEM) the theoretical resolution is calculated to be ∼1.5 nm (∼4 nm). Unlike previous designs, this instrument makes use of two magnetic prism arrays to guide the electron beam from the sample to the electron mirror, removing chromatic dispersion in front of the mirror by symmetry. The aberration correction optics was retrofitted to an uncorrected instrument with a base resolution of 4.1 nm in LEEM. Initial results in LEEM show an improvement in resolution to ∼2 nm.

Intershell correlations in photoionization of outer shells

Energy Technology Data Exchange (ETDEWEB)

Amusia, M.Ya. [The Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel); A.F. Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Chernysheva, L.V. [A.F. Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Drukarev, E.G. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute, St. Petersburg 188300 (Russian Federation)

2016-02-15

We demonstrate that the cross sections for photoionization of the outer shells are noticeably modified at the photon energies close to the thresholds of ionization of the inner shells due to correlations with the latter. The correlations may lead to increase or to decrease of the cross sections just above the ionization thresholds.

Intershell correlations in photoionization of outer shells

International Nuclear Information System (INIS)

Amusia, M.Ya.; Chernysheva, L.V.; Drukarev, E.G.

2016-01-01

We demonstrate that the cross sections for photoionization of the outer shells are noticeably modified at the photon energies close to the thresholds of ionization of the inner shells due to correlations with the latter. The correlations may lead to increase or to decrease of the cross sections just above the ionization thresholds.

Fabrication of CuO–Pt core–shell nanohooks by in situ reconstructing the Pt-shells

Science.gov (United States)

Cao, Fan; Zheng, He; Zhao, Ligong; Huang, Rui; Jia, Shuangfeng; Liu, Huihui; Li, Lei; Wang, Zhao; Hu, Yongming; Gu, Haoshuang; Wang, Jianbo

2018-05-01

The design of various nanostructures with specific compositions and shapes is highly demanded due to the widespread use of micro/nano electro-mechanical systems. In this work, one-dimensional CuO–Pt core–shell nanowires (NWs) are acquired by depositing Pt nanoparticles onto CuO NWs and then mechanically-shaped into nanohooks. Subsequently, the hook-like shape is maintained by the Pt-shell which is reconstructed via Joule heat and re-solidified after cooling down, during which the elastic strain energy is stored in the CuO-core. The results provide a simple strategy to design nanostructures with various compositions and shapes, implying the potential applications in mechanical energy storage and shape memory nanodevices.

Quantum corrections to potential energy surfaces and their influence on barriers

International Nuclear Information System (INIS)

Reinhard, P.G.; Goeke, K.W.; Bonn Univ.

1980-01-01

A microscopic theory suitable for the description of fission processes and other large-amplitude collective phenomena is presented. The approach makes use of an optimal collective path, which is constructed by means of adiabatic time-dependent Hartree-Fock (TDHF) techniques as to show maximal de-coupling of collective and non-collective degrees of freedom. Although this involves a classical concept, the theory fully incorporates quantum effects associated with extracting a collective Schroedinger equation from adiabatic time-dependent Hartree-Fock theories (ATDHF). The quantum corrections are discussed extensively, and calculations in the two-centre shell model show, e.g. that they reduce the second barrier by 2 MeV and the life-time by a factor of 10 -7 . The relationships of the presented quantized ATDHF approach to the random-phase approximation (RPA) and a generalized dynamic generator co-ordinate method are investigated. For the construction of the optimal fission path, simple step-by-step methods are suggested. (author)

Atomic mass prediction from the mass formula with empirical shell terms

International Nuclear Information System (INIS)

Uno, Masahiro; Yamada, Masami

1982-08-01

The mass-excess prediction of about 8000 nuclides was calculated from two types of the atomic mass formulas with empirical shell terms of Uno and Yamada. The theoretical errors to accompany the calculated mass excess are also presented. These errors have been obtained by a new statistical method. The mass-excess prediction includes the term of the gross feature of a nuclear mass surface, the shell terms and a small correction term for odd-odd nuclei. Two functional forms for the shell terms were used. The first is the constant form, and the sencond is the linear form. In determining the values of shell parameters, only the data of even-even and odd-A nuclei were used. A new statistical method was applied, in which the error inherent to the mass formula was taken account. The obtained shell parameters and the values of mass excess are shown in tables. (Kato, T.)

Equivalence of the spherical and deformed shell-model approach to intruder states

International Nuclear Information System (INIS)

Heyde, K.; Coster, C. de; Ryckebusch, J.; Waroquier, M.

1989-01-01

We point out that the description of intruder states, incorporating particle-hole (p-h) excitation across a closed shell in the spherical shell model or a description starting from the Nilsson model are equivalent. We furthermore indicate that the major part of the nucleon-nucleon interaction, responsible for the low excitation energy of intruder states comes as a two-body proton-neutron quadrupole interaction in the spherical shell model. In the deformed shell model, quadrupole binding energy is gained mainly through the one-body part of the potential. (orig.)

A finite-element for the analysis of shell intersections

International Nuclear Information System (INIS)

Koves, W.J.; Nair, S.

1994-01-01

The analysis of discontinuity stresses at shell intersections is a problem of great importance in several major industries. Some of the major areas of interest are pressure-containing equipment, such as reactors and piping, in the nuclear and fossil power industry; pressure vessels and heat exchangers in the petrochemical industry; bracing in offshore oil platforms; and aerospace structures. A specialized shell-intersection finite element, which is compatible with adjoining shell elements, has been developed that has the capability of physically representing the complex three-dimensional geometry and stress state at shell intersections. The element geometry is a contoured shape that matches a wide variety of practical nozzle configurations used in ASME Code pressure vessel construction, and allows computational rigor. A closed-form theory of elasticity solution was used to compute the stress state and strain energy in the element. The concept of an energy-equivalent nodal displacement and force vector set was then developed to allow complete compatibility with adjoining shell elements and retain the analytical rigor within the element. This methodology provides a powerful and robust computation scheme that maintains the computational efficiency of shell element solutions. The shell-intersection element was then applied to the cylinder-sphere and cylinder-cylinder intersection problems

Simultaneous K plus L shell ionized atoms during heavy-ion ...

Indian Academy of Sciences (India)

The fraction of simultaneous K plus L shell ionized atoms is estimated in Fe, Co and Cu elements using carbon ions at different projectile energies. The present results indicate that the fraction of simultaneous K plus L shell ionization probability decreases with increase in projectile energy as well as with increase in the ...

Author Correction: Implications of net energy-return-on-investment for a low-carbon energy transition

Science.gov (United States)

King, Lewis C.; van den Bergh, Jeroen C. J. M.

2018-04-01

In the version of this Analysis originally published, the value of the pessimistic EROI for the geothermal energy source in Table 1 was incorrectly given as 14:1; it should have read 9:1. This has now been corrected in all versions of the Analysis.

Reparameterization invariance of NRQED self-energy corrections and improved theory for excited D states in hydrogenlike systems

International Nuclear Information System (INIS)

Wundt, Benedikt J.; Jentschura, Ulrich D.

2008-01-01

Canonically, the quantum electrodynamic radiative corrections in bound systems have been evaluated in photon energy regularization, i.e., using a noncovariant overlapping parameter that separates the high-energy relativistic scales of the virtual quanta from the nonrelativistic domain. Here, we calculate the higher-order corrections to the one-photon self-energy calculation with three different overlapping parameters (photon energy, photon mass and dimensional regularization) and demonstrate the reparameterization invariance of nonrelativistic quantum electrodynamics (NRQED) using this particular example. We also present new techniques for the calculation of the low-energy part of this correction, which lead to results for the Lamb shift of highly excited states that are important for high-precision spectroscopy

Reparameterization invariance of NRQED self-energy corrections and improved theory for excited D states in hydrogenlike systems

Energy Technology Data Exchange (ETDEWEB)

Wundt, Benedikt J. [Max-Planck-Institut fuer Kernphysik, Postfach 103980, 69029 Heidelberg (Germany); Jentschura, Ulrich D. [Max-Planck-Institut fuer Kernphysik, Postfach 103980, 69029 Heidelberg (Germany); Institut fuer Theoretische Physik, Philosophenweg 16, 69120 Heidelberg (Germany)], E-mail: ulrich.jentschura@mpi-hd.mpg.de

2008-01-24

Canonically, the quantum electrodynamic radiative corrections in bound systems have been evaluated in photon energy regularization, i.e., using a noncovariant overlapping parameter that separates the high-energy relativistic scales of the virtual quanta from the nonrelativistic domain. Here, we calculate the higher-order corrections to the one-photon self-energy calculation with three different overlapping parameters (photon energy, photon mass and dimensional regularization) and demonstrate the reparameterization invariance of nonrelativistic quantum electrodynamics (NRQED) using this particular example. We also present new techniques for the calculation of the low-energy part of this correction, which lead to results for the Lamb shift of highly excited states that are important for high-precision spectroscopy.

Ni(3)Si(Al)/a-SiO(x) core-shell nanoparticles: characterization, shell formation, and stability.

Science.gov (United States)

Pigozzi, G; Mukherji, D; Gilles, R; Barbier, B; Kostorz, G

2006-08-28

We have used an electrochemical selective phase dissolution method to extract nanoprecipitates of the Ni(3)Si-type intermetallic phase from two-phase Ni-Si and Ni-Si-Al alloys by dissolving the matrix phase. The extracted nanoparticles are characterized by transmission electron microscopy, energy-dispersive x-ray spectrometry, x-ray powder diffraction, and electron powder diffraction. It is found that the Ni(3)Si-type nanoparticles have a core-shell structure. The core maintains the size, the shape, and the crystal structure of the precipitates that existed in the bulk alloys, while the shell is an amorphous phase, containing only Si and O (SiO(x)). The shell forms around the precipitates during the extraction process. After annealing the nanoparticles in nitrogen at 700 °C, the tridymite phase recrystallizes within the shell, which remains partially amorphous. In contrast, on annealing in air at 1000 °C, no changes in the composition or the structure of the nanoparticles occur. It is suggested that the shell forms after dealloying of the matrix phase, where Si atoms, the main constituents of the shell, migrate to the surface of the precipitates.

Electrical and magnetic properties of the energy-saver correction elements

International Nuclear Information System (INIS)

Johnson, M.; McInturff, A.; Raja, R.; Mantsch, P.

1983-08-01

The lattice of the Fermi National Accelerator Laboratory's Energy Saver/Doubler contains a group of superconducting correction windings associated with each quadrupole. These are housed in an element referred to as a spool. There are 192 spools in the ring plus 12 special power spools which contain the main buss 5000 ampere power input as well as correction elements. There will be constructed and tested 290 spools, including spares of each of the eight different types. There have been 266 individual spools tested to date. The spools were tested for (a) magnetic field quality, harmonic moments, transfer constants and coil angles, (b) high voltage integrity, (c) critical transport current, and (d) cryogenic operating characteristics (i.e., heatloads, thermometry calibration checks, etc.). Data are summarized for 318 cryogenic tests and magnetic field quality of the 266 different spools, which contain 1614 correction magnet coils

Nuclear shell effects at high temperatures

International Nuclear Information System (INIS)

Davidson, N.J.; Miller, H.G.

1993-01-01

In discussing the disappearance of nuclear shell effects at high temperatures, it is important to distinguish between the ''smearing out'' of the single-particle spectrum with increasing temperature and the vanishing of shell related structures in many-body quantities such as the excitation energy per nucleon. We propose a semiempirical method to obtain an upper bound on the temperature required to smooth the single-particle spectrum, and point out that shell effects in many-body parameters may persist above this temperature. We find that the temperature required to smear out the single-particle spectrum is approximately 1 MeV for heavy nuclei (A approx-gt 150) and about 3--4 MeV for light nuclei (A approx-lt 50), in reasonable agreement with the estimate of 41/πA 1/3 obtained from calculations with harmonic oscillator potentials. These temperatures correspond to many-body excitation energies of approximately 20 and 60 MeV, respectively

40 Years of Shell Scenarios

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-02-15

Shell has been using scenario planning for four decades. During that time these scenarios have helped the company and governments across the world to make better strategic choices. Scenarios provide lenses that help see future prospects more clearly, make richer judgments and be more sensitive to uncertainties. Discover how the Shell Scenarios team has helped guide decision makers at major moments in history and get a peek at the team future focus, including the intricate relationship between energy, water and food.

WKB corrections to the energy splitting in double-well potentials

OpenAIRE

Robnik, Marko; Salasnich, Luca

1997-01-01

By using the WKB quantization we deduce an analytical formula for the energy splitting in a double-well potential which is the usual Landau formula with additional quantum corrections. Then we analyze the accuracy of our formula for the double square well potential and the parabolic double-well potential.

Thermoelectric-pyroelectric hybrid energy generation from thermopower waves in core-shell structured carbon nanotube-PZT nanocomposites.

Science.gov (United States)

Yeo, Taehan; Hwang, Hayoung; Shin, Dongjoon; Seo, Byungseok; Choi, Wonjoon

2017-02-10

There is an urgent need to develop a suitable energy source owing to the rapid development of various innovative devices using micro-nanotechnology. The thermopower wave (TW), which produces a high specific power during the combustion of solid fuel inside micro-nanostructure materials, is a unique energy source for unusual platforms that cannot use conventional energy sources. Here, we report on the significant enhancement of hybrid energy generation of pyroelectrics and thermoelectrics from TWs in carbon nanotube (CNT)-PZT (lead zirconate titanate, P(Z 0.5 -T 0.5 )) composites for the first time. Conventional TWs use only charge carrier transport driven by the temperature gradient along the core materials to produce voltage. In this study, a core-shell structure of CNTs-PZTs was prepared to utilize both the temperature gradient along the core material (thermoelectrics) and the dynamic change in the temperature of the shell structure (pyroelectrics) induced by TWs. The dual mechanism of energy generation in CNT-PZT composites amplified the average peak and duration of the voltage up to 403 mV and 612 ms, respectively, by a factor of 2 and 60 times those for the composites without a PZT layer. Furthermore, dynamic voltage measurements and structural analysis in repetitive TWs confirmed that CNT-PZT composites maintain the original performance in multiple TWs, which improves the reusability of materials. The advanced TWs obtained by the application of a PZT layer as a pyroelectric material contributes to the extension of the usable energy portion as well as the development of TW-based operating devices.

Strontium clusters: electronic and geometry shell effects

DEFF Research Database (Denmark)

Lyalin, Andrey G.; Solov'yov, Ilia; Solov'yov, Andrey V.

2008-01-01

charged strontium clusters consisting of up to 14 atoms, average bonding distances, electronic shell closures, binding energies per atom, and spectra of the density of electronic states (DOS). It is demonstrated that the size-evolution of structural and electronic properties of strontium clusters...... is governed by an interplay of the electronic and geometry shell closures. Influence of the electronic shell effects on structural rearrangements can lead to violation of the icosahedral growth motif of strontium clusters. It is shown that the excessive charge essentially affects the optimized geometry...

Interacting entropy-corrected new agegraphic dark energy in the non-flat universe

Energy Technology Data Exchange (ETDEWEB)

Karami, Kayoomars [Department of Physics, University of Kurdistan, Pasdaran Street, Sanandaj (Iran, Islamic Republic of); Sorouri, Arash, E-mail: KKarami@uok.ac.i [Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of)

2010-08-15

Here, we consider the entropy-corrected version of the new agegraphic dark energy (NADE) model in the non-flat Friedmann-Robertson-Walker universe. We derive the exact differential equation that determines the evolution of the entropy-corrected NADE density parameter in the presence of interaction with dark matter. We also obtain the equation of state and deceleration parameters and present a necessary condition for the selected model to cross the phantom divide. Moreover, we reconstruct the potential and the dynamics of the phantom scalar field according to the evolutionary behavior of the interacting entropy-corrected new agegraphic model.

Stability analysis of thin-shell wormholes from charged black string

Energy Technology Data Exchange (ETDEWEB)

Sharif, M.; Azam, M., E-mail: msharif.math@pu.edu.pk, E-mail: azammath@gmail.com [Department of Mathematics, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590 (Pakistan)

2013-04-01

In this paper, we construct thin-shell wormholes from charged black string through cut and paste procedure and investigate its stability. We assume modified generalized Chaplygin gas as a dark energy fluid (exotic matter) present in the thin layer of matter-shell. The stability of these constructed thin-shell wormholes is investigated in the scenario of linear perturbations. We conclude that static stable as well as unstable configurations are possible for cylindrical thin-shell wormholes.

Predictable Particle Engineering: Programming the Energy Level, Carrier Generation, and Conductivity of Core-Shell Particles.

Science.gov (United States)

Yuan, Conghui; Wu, Tong; Mao, Jie; Chen, Ting; Li, Yuntong; Li, Min; Xu, Yiting; Zeng, Birong; Luo, Weiang; Yu, Lingke; Zheng, Gaofeng; Dai, Lizong

2018-06-20

Core-shell structures are of particular interest in the development of advanced composite materials as they can efficiently bring different components together at nanoscale. The advantage of this structure greatly relies on the crucial design of both core and shell, thus achieving an intercomponent synergistic effect. In this report, we show that decorating semiconductor nanocrystals with a boronate polymer shell can easily achieve programmable core-shell interactions. Taking ZnO and anatase TiO 2 nanocrystals as inner core examples, the effective core-shell interactions can narrow the band gap of semiconductor nanocrystals, change the HOMO and LUMO levels of boronate polymer shell, and significantly improve the carrier density of core-shell particles. The hole mobility of core-shell particles can be improved by almost 9 orders of magnitude in comparison with net boronate polymer, while the conductivity of core-shell particles is at most 30-fold of nanocrystals. The particle engineering strategy is based on two driving forces: catechol-surface binding and B-N dative bonding and having a high ability to control and predict the shell thickness. Also, this approach is applicable to various inorganic nanoparticles with different components, sizes, and shapes.

New method to evaluate optical properties of core-shell nanostructures

Energy Technology Data Exchange (ETDEWEB)

Renteria-Tapia, V. [Universidad de Guadalajara, Ameca, Departamento de Ciencias Naturales y Exactas, Centro Universitario de Los Valles (Mexico); Franco, A., E-mail: alfredofranco@fisica.unam.mx; Garcia-Macedo, J. [Universidad Nacional Autonoma de Mexico, Departamento de Estado Solido, Instituto de Fisica (Mexico)

2012-06-15

A new method is presented to calculate, for metallic core-dielectric shell nanostructures, the local refractive index, resonance condition, maximum spectral shift, plasma wavelength, and the sensitivity of the wavelength maximum to variations in the refractive index of the environment. The equations that describe these properties are directly related to the surface plasmon peak position, refractive index of the shell, and to the surrounding medium. The method is based on the approach that a layered core dispersed in a dielectric environment (core-shell model) can be figured out as an uncoated sphere dispersed in a medium with a local refractive index (local refractive index model). Thus, in the Mie theory, the same spectral position of the surface plasmon resonance peak can be obtained by varying the volume fraction of the shell or by varying the local refractive index. The assumed equivalence between plasmon resonance wavelengths enable us to show that the local refractive index depends geometrically on the shell volume fraction. Hence, simple relationships between optical and geometrical properties of these core-shell nanostructures are obtained. Furthermore, good agreement is observed between the new relationships and experimental data corresponding to gold nanoparticles (radius = 7.5 nm) covered with silica shells (with thicknesses up to 29.19 nm), which insured that the equivalence hypothesis is correct.

New method to evaluate optical properties of core–shell nanostructures

International Nuclear Information System (INIS)

Rentería-Tapia, V.; Franco, A.; García-Macedo, J.

2012-01-01

A new method is presented to calculate, for metallic core–dielectric shell nanostructures, the local refractive index, resonance condition, maximum spectral shift, plasma wavelength, and the sensitivity of the wavelength maximum to variations in the refractive index of the environment. The equations that describe these properties are directly related to the surface plasmon peak position, refractive index of the shell, and to the surrounding medium. The method is based on the approach that a layered core dispersed in a dielectric environment (core–shell model) can be figured out as an uncoated sphere dispersed in a medium with a local refractive index (local refractive index model). Thus, in the Mie theory, the same spectral position of the surface plasmon resonance peak can be obtained by varying the volume fraction of the shell or by varying the local refractive index. The assumed equivalence between plasmon resonance wavelengths enable us to show that the local refractive index depends geometrically on the shell volume fraction. Hence, simple relationships between optical and geometrical properties of these core–shell nanostructures are obtained. Furthermore, good agreement is observed between the new relationships and experimental data corresponding to gold nanoparticles (radius = 7.5 nm) covered with silica shells (with thicknesses up to 29.19 nm), which insured that the equivalence hypothesis is correct.

K-shell-hole production, multiple-hole production, charge transfer, and antisymmetry

International Nuclear Information System (INIS)

Reading, J.F.; Ford, A.L.

1980-01-01

In calculating K-shell-hole production when an ion collides with an atom, account must be taken of the fact that processes involving electrons other than the K-shell electron can occur. For example, after making a K-shell hole an L-shell electron may be knocked into it, or an L-shell vacancy may be produced and the K-shell electron promoted to that vacancy in the ''Fermi sea'' of the target-atom orbitals. In 1973 a theorem was proved by one of the present authors demonstrating that all these multielectron processes cancel in an independent-particle model for the target atom. In this paper it is shown that the same thing occurs for hole production by charge transfer to the ion. The authors demonstrate that multihole production does not obey this simple rule and that the probability for multihole production is not the product of independent single-electron probabilities. The correct expressions that should be used for these processes are given, together with new results for charge-transfer processes accompanied by hole production

Radar attenuation in Europa's ice shell: Obstacles and opportunities for constraining the shell thickness and its thermal structure

Science.gov (United States)

Kalousová, Klára; Schroeder, Dustin M.; Soderlund, Krista M.

2017-03-01

Young surface and possible recent endogenic activity make Europa one of the most exciting solar system bodies and a primary target for spacecraft exploration. Future Europa missions are expected to carry ice-penetrating radar instruments designed to investigate its subsurface thermophysical structure. Several authors have addressed the radar sounders' performance at icy moons, often ignoring the complex structure of a realistic ice shell. Here we explore the variation in two-way radar attenuation for a variety of potential thermal structures of Europa's shell (determined by reference viscosity, activation energy, tidal heating, surface temperature, and shell thickness) as well as for low and high loss temperature-dependent attenuation model. We found that (i) for all investigated ice shell thicknesses (5-30 km), the radar sounder will penetrate between 15% and 100% of the total thickness, (ii) the maximum penetration depth varies laterally, with deepest penetration possible through cold downwellings, (iii) direct ocean detection might be possible for shells of up to 15 km thick if the signal travels through cold downwelling ice or the shell is conductive, (iv) even if the ice/ocean interface is not directly detected, penetration through most of the shell could constrain the deep shell structure through returns from deep non-ocean interfaces or the loss of signal itself, and (v) for all plausible ice shells, the two-way attenuation to the eutectic point is ≲30 dB which shows a robust potential for longitudinal investigation of the ice shell's shallow thermophysical structure.

A new aberration-corrected, energy-filtered LEEM/PEEM instrument II. Operation and results

International Nuclear Information System (INIS)

Tromp, R.M.; Hannon, J.B.; Wan, W.; Berghaus, A.; Schaff, O.

2013-01-01

In Part I we described a new design for an aberration-corrected Low Energy Electron Microscope (LEEM) and Photo Electron Emission Microscope (PEEM) equipped with an in-line electron energy filter. The chromatic and spherical aberrations of the objective lens are corrected with an electrostatic electron mirror that provides independent control of the chromatic and spherical aberration coefficients C c and C 3 , as well as the mirror focal length. In this Part II we discuss details of microscope operation, how the microscope is set up in a systematic fashion, and we present typical results. - Highlights: ► The C c and C 3 aberrations of a LEEM/PEEM instrument are corrected with an electrostatic electron mirror. ► The mirror provides independent control over C c , C 3 and focal length in close agreement with theory. ► A detailed alignment procedure for the corrected microscope is given. ► Novel methods to measure C c and C 3 of the objective lens and the mirror are presented. ► We demonstrate a record spatial resolution of 2 nm

Decaying and kicked turbulence in a shell model

DEFF Research Database (Denmark)

Hooghoudt, Jan Otto; Lohse, Detlef; Toschi, Federico

2001-01-01

Decaying and periodically kicked turbulence are analyzed within the Gledzer–Ohkitani–Yamada shell model, to allow for sufficiently large scaling regimes. Energy is transferred towards the small scales in intermittent bursts. Nevertheless, mean field arguments are sufficient to account for the ens......Decaying and periodically kicked turbulence are analyzed within the Gledzer–Ohkitani–Yamada shell model, to allow for sufficiently large scaling regimes. Energy is transferred towards the small scales in intermittent bursts. Nevertheless, mean field arguments are sufficient to account...

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

DEFF Research Database (Denmark)

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

2017-01-01

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

Microscopic description of quadrupole collectivity in neutron-rich nuclei across the N = 126 shell closure

Science.gov (United States)

Rodríguez-Guzmán, R.; Robledo, L. M.; Sharma, M. M.

2015-06-01

The quadrupole collectivity in Nd, Sm, Gd, Dy, Er, Yb, Hf and W nuclei with neutron numbers 122 ≤ N ≤ 156 is studied, both at the mean field level and beyond, using the Gogny energy density functional. Besides the robustness of the N = 126 neutron shell closure, it is shown that the onset of static deformations in those isotopic chains with increasing neutron number leads to an enhanced stability and further extends the corresponding two-neutron drip lines far beyond what could be expected from spherical calculations. Independence of the mean-field predictions with respect to the particular version of the Gogny energy density functional employed is demonstrated by comparing results based on the D1S and D1M parameter sets. Correlations beyond mean field are taken into account in the framework of the angular momentum projected generator coordinate method calculation. It is shown that N = 126 remains a robust neutron magic number when dynamical effects are included. The analysis of the collective wave functions, average deformations and excitation energies indicate that, with increasing neutron number, the zero-point quantum corrections lead to dominant prolate configurations in the 0{1/+}, 0{2/+}, 2{1/+} and 2{2/+} states of the studied nuclei. Moreover, those dynamical deformation effects provide an enhanced stability that further supports the mean-field predictions, corroborating a shift of the r-process path to higher neutron numbers. Beyond mean-field calculations provide a smaller shell gap at N = 126 than the mean-field one in good agreement with previous theoretical studies. However, the shell gap still remains strong enough in the two-neutron drip lines.

Evaluation of a scattering correction method for high energy tomography

Science.gov (United States)

Tisseur, David; Bhatia, Navnina; Estre, Nicolas; Berge, Léonie; Eck, Daniel; Payan, Emmanuel

2018-01-01

One of the main drawbacks of Cone Beam Computed Tomography (CBCT) is the contribution of the scattered photons due to the object and the detector. Scattered photons are deflected from their original path after their interaction with the object. This additional contribution of the scattered photons results in increased measured intensities, since the scattered intensity simply adds to the transmitted intensity. This effect is seen as an overestimation in the measured intensity thus corresponding to an underestimation of absorption. This results in artifacts like cupping, shading, streaks etc. on the reconstructed images. Moreover, the scattered radiation provides a bias for the quantitative tomography reconstruction (for example atomic number and volumic mass measurement with dual-energy technique). The effect can be significant and difficult in the range of MeV energy using large objects due to higher Scatter to Primary Ratio (SPR). Additionally, the incident high energy photons which are scattered by the Compton effect are more forward directed and hence more likely to reach the detector. Moreover, for MeV energy range, the contribution of the photons produced by pair production and Bremsstrahlung process also becomes important. We propose an evaluation of a scattering correction technique based on the method named Scatter Kernel Superposition (SKS). The algorithm uses a continuously thickness-adapted kernels method. The analytical parameterizations of the scatter kernels are derived in terms of material thickness, to form continuously thickness-adapted kernel maps in order to correct the projections. This approach has proved to be efficient in producing better sampling of the kernels with respect to the object thickness. This technique offers applicability over a wide range of imaging conditions and gives users an additional advantage. Moreover, since no extra hardware is required by this approach, it forms a major advantage especially in those cases where

Three-body forces in p-shell nuclei

International Nuclear Information System (INIS)

Hees, A.G.M. van; Booten, J.G.L.; Glaudemans, P.W.M.

1990-01-01

Within the (0 + 1)ℎω shell-model space for p-shell nuclei we found that a schematic three-body interaction in addition to a translationally invariant two-body interaction leads to a strongly improved description of energy levels. The present three-body interaction is related to the Δ-isobar intermediate-state model of the two-pion exchange three-nucleon interaction. (orig.)

Radiative corrections for associated ZH production at future e+e- colliders

International Nuclear Information System (INIS)

Kniehl, B.A.

1991-11-01

The ZHfanti f four-point function is calculated in the one-loop approximation of the Standard Model and full analytic results are presented. The loop contributions due to both light and new heavy fermions are inspected in detail. The dominant mechanisms of Higgs-boson production from fermions are compared. The effect of radiative corrections on the cross section of fanti f→ZH including bremsstrahlung is studied. The spectrum of hard bremsstrahlung is integrated analytically. The implications for Higgs-boson searches at future e + e - colliders in the energy range 200 GeV≤√s≤1.5 TeV, which includes both LEP 2 and the Next Linear Collider, are analyzed. At √s=500 GeV, for instance, weak corrections in the modified on-mass-shell scheme vary between -2% and +7%, depending on the actual values of the Higgs-boson and top-quark masses. Electromagnetic corrections strongly reduce the cross section close to the ZH-production threshold, while they may considerably enhance it far above threshold. (orig.)

Higgs production in association with off-shell top-antitop pairs at NLO EW and QCD at the LHC

Energy Technology Data Exchange (ETDEWEB)

Denner, Ansgar; Lang, Jean-Nicolas; Pellen, Mathieu [Universität Würzburg, Institut für Theoretische Physik und Astrophysik,97074 Würzburg (Germany); Uccirati, Sandro [Università di Torino e INFN,10125 Torino (Italy)

2017-02-09

We present NLO electroweak corrections to Higgs production in association with off-shell top-antitop quark pairs. The full process pp→e{sup +}ν{sub e}μ{sup −}ν̄{sub μ}bb̄H is considered, and hence all interference, off-shell, and non-resonant contributions are taken into account. The electroweak corrections turn out to be below one per cent for the integrated cross section but can exceed 10% in certain phase-space regions. In addition to its phenomenological relevance, the computation constitutes a major technical achievement as the full NLO virtual corrections involving up to 9-point functions have been computed exactly. The results of the full computation are supported by two calculations in the double-pole approximation. These also allow to infer the effect of off-shell contributions and emphasise their importance especially for the run II of the LHC. Finally, we present combined predictions featuring both NLO electroweak and QCD corrections in a common set-up that will help the experimental collaborations in their quest of precisely measuring the aforementioned process.

Higgs production in association with off-shell top-antitop pairs at NLO EW and QCD at the LHC

International Nuclear Information System (INIS)

Denner, Ansgar; Lang, Jean-Nicolas; Pellen, Mathieu; Uccirati, Sandro

2017-01-01

We present NLO electroweak corrections to Higgs production in association with off-shell top-antitop quark pairs. The full process pp→e + ν e μ − ν̄ μ bb̄H is considered, and hence all interference, off-shell, and non-resonant contributions are taken into account. The electroweak corrections turn out to be below one per cent for the integrated cross section but can exceed 10% in certain phase-space regions. In addition to its phenomenological relevance, the computation constitutes a major technical achievement as the full NLO virtual corrections involving up to 9-point functions have been computed exactly. The results of the full computation are supported by two calculations in the double-pole approximation. These also allow to infer the effect of off-shell contributions and emphasise their importance especially for the run II of the LHC. Finally, we present combined predictions featuring both NLO electroweak and QCD corrections in a common set-up that will help the experimental collaborations in their quest of precisely measuring the aforementioned process.

Polystyrene-Core, Silica-Shell Scintillant Nanoparticles for Low-Energy Radionuclide Quantification in Aqueous Media.

Science.gov (United States)

Janczak, Colleen M; Calderon, Isen A C; Mokhtari, Zeinab; Aspinwall, Craig A

2018-02-07

β-particle emitting radionuclides are useful molecular labels due to their abundance in biomolecules. Detection of β-emission from 3 H, 35 S, and 33 P, important biological isotopes, is challenging due to the low energies (E max ≤ 300 keV) and short penetration depths (≤0.6 mm) in aqueous media. The activity of biologically relevant β-emitters is usually measured in liquid scintillation cocktail (LSC), a mixture of energy-absorbing organic solvents, surfactants, and scintillant fluorophores, which places significant limitations on the ability to acquire time-resolved measurements directly in aqueous biological systems. As an alternative to LSC, we developed polystyrene-core, silica-shell nanoparticle scintillators (referred to as nanoSCINT) for quantification of low-energy β-particle emitting radionuclides directly in aqueous solutions. The polystyrene acts as an absorber for energy from emitted β-particles and can be loaded with a range of hydrophobic scintillant fluorophores, leading to photon emission at visible wavelengths. The silica shell serves as a hydrophilic shield for the polystyrene core, enabling dispersion in aqueous media and providing better compatibility with water-soluble analytes. While polymer and inorganic scintillating microparticles are commercially available, their large size and/or high density complicates effective dispersion throughout the sample volume. In this work, nanoSCINT nanoparticles were prepared and characterized. nanoSCINT responds to 3 H, 35 S, and 33 P directly in aqueous solutions, does not exhibit a change in scintillation response between pH 3.0 and 9.5 or with 100 mM NaCl, and can be recovered and reused for activity measurements in bulk aqueous samples, demonstrating the potential for reduced production of LSC waste and reduced total waste volume during radionuclide quantification. The limits of detection for 1 mg/mL nanoSCINT are 130 nCi/mL for 3 H, 8 nCi/mL for 35 S, and <1 nCi/mL for 33 P.

Inner shell excitation in atoms and molecules by high resolution electron impact

International Nuclear Information System (INIS)

King, G.C.

1986-01-01

In this work an inner-shell spin-forbidden transition in N 2 and a parity-forbidden transition in Ar were studied. These transitions were observed by using incident electron energies as low as 1.15 times the excitation energy of the inner-shell states. (Auth.)

Energy-correction photon counting pixel for photon energy extraction under pulse pile-up

Energy Technology Data Exchange (ETDEWEB)

Lee, Daehee; Park, Kyungjin; Lim, Kyung Taek; Cho, Gyuseong, E-mail: gscho@kaist.ac.kr

2017-06-01

A photon counting detector (PCD) has been proposed as an alternative solution to an energy-integrating detector (EID) in medical imaging field due to its high resolution, high efficiency, and low noise. The PCD has expanded to variety of fields such as spectral CT, k-edge imaging, and material decomposition owing to its capability to count and measure the number and the energy of an incident photon, respectively. Nonetheless, pulse pile-up, which is a superimposition of pulses at the output of a charge sensitive amplifier (CSA) in each PC pixel, occurs frequently as the X-ray flux increases due to the finite pulse processing time (PPT) in CSAs. Pulse pile-up induces not only a count loss but also distortion in the measured X-ray spectrum from each PC pixel and thus it is a main constraint on the use of PCDs in high flux X-ray applications. To minimize these effects, an energy-correction PC (ECPC) pixel is proposed to resolve pulse pile-up without cutting off the PPT by adding an energy correction logic (ECL) via a cross detection method (CDM). The ECPC pixel with a size of 200×200 µm{sup 2} was fabricated by using a 6-metal 1-poly 0.18 µm CMOS process with a static power consumption of 7.2 μW/pixel. The maximum count rate of the ECPC pixel was extended by approximately three times higher than that of a conventional PC pixel with a PPT of 500 nsec. The X-ray spectrum of 90 kVp, filtered by 3 mm Al filter, was measured as the X-ray current was increased using the CdTe and the ECPC pixel. As a result, the ECPC pixel dramatically reduced the energy spectrum distortion at 2 Mphotons/pixel/s when compared to that of the ERCP pixel with the same 500 nsec PPT.

Image enhancement by spectral-error correction for dual-energy computed tomography.

Science.gov (United States)

Park, Kyung-Kook; Oh, Chang-Hyun; Akay, Metin

2011-01-01

Dual-energy CT (DECT) was reintroduced recently to use the additional spectral information of X-ray attenuation and aims for accurate density measurement and material differentiation. However, the spectral information lies in the difference between low and high energy images or measurements, so that it is difficult to acquire accurate spectral information due to amplification of high pixel noise in the resulting difference image. In this work, an image enhancement technique for DECT is proposed, based on the fact that the attenuation of a higher density material decreases more rapidly as X-ray energy increases. We define as spectral error the case when a pixel pair of low and high energy images deviates far from the expected attenuation trend. After analyzing the spectral-error sources of DECT images, we propose a DECT image enhancement method, which consists of three steps: water-reference offset correction, spectral-error correction, and anti-correlated noise reduction. It is the main idea of this work that makes spectral errors distributed like random noise over the true attenuation and suppressed by the well-known anti-correlated noise reduction. The proposed method suppressed noise of liver lesions and improved contrast between liver lesions and liver parenchyma in DECT contrast-enhanced abdominal images and their two-material decomposition.

The congruence energy: a contribution to nuclear masses, deformation energies and fission barriers

International Nuclear Information System (INIS)

Myers, W.D.; Swiatecki, W.J.

1997-01-01

The difference between measured binding energies and those calculated using a shell- and pairing-corrected Thomas-Fermi model can be described approximately by C(I)=-10 exp(-4.2 vertical stroke I vertical stroke) MeV, where I=(N-Z)/A. Our interpretation of this extra binding is in terms of the granularity of quantal nucleonic density distributions, which leads to a stronger interaction for a neutron and proton with congruent nodal structures of their wave functions. The predicted doubling of this congruence energy in fission is supported by an analysis of measured fission barriers and by a study of wave functions in a dividing Hill-Wheeler box potential. A semi-empirical formula for the shape-dependent congruence energy is described. (orig.)

The energy efficiency ratio of heat storage in one shell-and-one tube phase change thermal energy storage unit

International Nuclear Information System (INIS)

Wang, Wei-Wei; Wang, Liang-Bi; He, Ya-Ling

2015-01-01

Highlights: • A parameter to indicate the energy efficiency ratio of PCTES units is defined. • The characteristics of the energy efficiency ratio of PCTES units are reported. • A combined parameter of the physical properties of the working mediums is found. • Some implications of the energy efficiency ratio in design of PCTES units are analyzed. - Abstract: From aspect of energy consuming to pump heat transfer fluid, there is no sound basis on which to create an optimum design of a thermal energy storage unit. Thus, it is necessary to develop a parameter to indicate the energy efficiency of such unit. This paper firstly defines a parameter that indicates the ratio of heat storage of phase change thermal energy storage unit to energy consumed in pumping heat transfer fluid, which is called the energy efficiency ratio, then numerically investigates the characteristics of this parameter. The results show that the energy efficiency ratio can clearly indicate the energy efficiency of a phase change thermal energy storage unit. When the fluid flow of a heat transfer fluid is in a laminar state, the energy efficiency ratio is larger than in a turbulent state. The energy efficiency ratio of a shell-and-tube phase change thermal energy storage unit is more sensitive to the outer tube diameter. Under the same working conditions, within the heat transfer fluids studied, the heat storage property of the phase change thermal energy storage unit is best for water as heat transfer fluid. A combined parameter is found to indicate the effects of both the physical properties of phase change material and heat transfer fluid on the energy efficiency ratio

Ge/Si core/multi shell heterostructure FETs

Energy Technology Data Exchange (ETDEWEB)

Picraux, Samuel T [Los Alamos National Laboratory; Dayeh, Shadi A [Los Alamos National Laboratory

2010-01-01

Concentric heterostructured materials provide numerous design opportunities for engineering strain and interfaces, as well as tailoring energy band-edge combinations for optimal device performance. Key to the realization of such novel device concepts is the complete understanding and full control over their growth, crystal structure, and hetero-epitaxy. We report here on a new route for synthesizing Ge/Si core/multi-shell heterostructure nanowires that eliminate Au seed diffusion on the nanowire sidewalls by engineering the interface energy density difference. We show that such control over core/shell synthesis enable experimental realization of heterostructure FET devices beyond those available in the literature with enhanced transport characteristics. We provide a side-by-side comparison on the transport properties of Ge/Si core/multi-shell nanowires grown with and without Au diffusion and demonstrate heterostructure FETs with drive currents that are {approx} 2X higher than record results for p-type FETs.

CoFFEE: Corrections For Formation Energy and Eigenvalues for charged defect simulations

Science.gov (United States)

Naik, Mit H.; Jain, Manish

2018-05-01

Charged point defects in materials are widely studied using Density Functional Theory (DFT) packages with periodic boundary conditions. The formation energy and defect level computed from these simulations need to be corrected to remove the contributions from the spurious long-range interaction between the defect and its periodic images. To this effect, the CoFFEE code implements the Freysoldt-Neugebauer-Van de Walle (FNV) correction scheme. The corrections can be applied to charged defects in a complete range of material shapes and size: bulk, slab (or two-dimensional), wires and nanoribbons. The code is written in Python and features MPI parallelization and optimizations using the Cython package for slow steps.

Fission excitation function for 19F + 194,196,198Pt at near and above barrier energies

Directory of Open Access Journals (Sweden)

Singh Varinderjit

2015-01-01

Full Text Available Fission excitation functions for 19F + 194,196,198Pt reactions populating 213,215,217Fr compound nuclei are reported. Out of these three compound nuclei, 213Fr is a shell closed (N=126 compound nucleus and the other two are away from the shell closure. From a comparison of the experimental fission cross-sections with the statistical model predictions, it is observed that the fission cross-sections are underestimated by the statistical model predictions using shell corrected finite range rotating liquid drop model (FRLDM fission barriers. Further the FRLDM fission barriers are reduced to fit the fission cross-sections over the entire measured energy range.

Microencapsulated n-octadecane with different methylmethacrylate-based copolymer shells as phase change materials for thermal energy storage

International Nuclear Information System (INIS)

Qiu, Xiaolin; Li, Wei; Song, Guolin; Chu, Xiaodong; Tang, Guoyi

2012-01-01

Microcapsules containing n-octadecane with different methylmethacrylate (MMA (methyl methacrylate))-based copolymer shells were fabricated by a suspension-like polymerization. Butyl acrylate (BA), butyl methacrylate (BMA), lauryl methacrylate (LMA) and stearyl methacrylate (SMA) were employed as monomers to copolymerize with MMA. Pentaerythritol tetraacrylate (PETRA) was employed as a crosslinking agent. The (microencapsulted phase change materials) MicroPCMs were characterized using Fourier transformed infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Thermal properties and thermal resistances of MicroPCMs were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), respectively. Phase change enthalpies and PCM contents of MicroPCMs increased with the length decreasing of the side chain of the monomers. The n-octadecane content of as much as 77.3% can be obtained in the crosslinked MicroPCMs with P(MMA-co-BMA) as shell, and accompanied by the highest melting enthalpy (173.7 J/g) and crystallization enthalpy (174.4 J/g). Heat capacities of crosslinked MicroPCMs are higher than those of their uncrosslinked counterparts. The crosslinked MicroPCMs exhibit significantly greater thermal stabilities compared with their uncrosslinked counterparts and the n-ontadecane bulk. The crosslinked MicroPCMs with P(MMA-co-SMA) displays the highest thermal resistance temperature up to 255 °C. Therefore, MicroPCMs with MMA-based copolymer as shells, especially crosslinked copolymer shells, show excellent potentials for thermal energy storage. -- Highlights: ► n-Octadecane was encapsulated with methylmethacrylate(MMA)-based copolymer shells. ► n-Octadecane content of Microcapsules increased with length decreasing of side chain of monomers. ► Microcapsule with P(MMA-co-butyl methacrylate) has the highest latent heat. ► Microcapsule with P(MMA-co-stearyl methacrylate) has the greatest thermal stability.

Binding and Pauli principle corrections in subthreshold pion-nucleus scattering

International Nuclear Information System (INIS)

Kam, J. de

1981-01-01

In this investigation I develop a three-body model for the single scattering optical potential in which the nucleon binding and the Pauli principle are accounted for. A unitarity pole approximation is used for the nucleon-core interaction. Calculations are presented for the π- 4 He elastic scattering cross sections at energies below the inelastic threshold and for the real part of the π- 4 He scattering length by solving the three-body equations. Off-shell kinematics and the Pauli principle are carefully taken into account. The binding correction and the Pauli principle correction each have an important effect on the differential cross sections and the scattering length. However, large cancellations occur between these two effects. I find an increase in the π- 4 He scattering length by 100%; an increase in the cross sections by 20-30% and shift of the minimum in π - - 4 He scattering to forward angles by 10 0 . (orig.)

The two-photon self-energy and other QED radiative corrections

International Nuclear Information System (INIS)

Zschocke, S.

2001-07-01

One of the main issues in current nuclear physics is the precise measurement of the Lamb shift of strongly bound electrons in quantum electrodynamic (QED) tests in strong fields in highly charged ions. The currently performed high-precision measurements require extreme accuracy in the theoretical calculation of Lamb shift. This requires consideration of all α and α 2 order QED corrections as well as of precisely all orders in Zα. In the past years most of these QED corrections have been calculated both in 1st order and in 2nd order interference theory. As yet however, it has not been possible to assess the contribution of the two-photon self-energy, which has therefore been the greatest uncertainty factor in predicting Lamb shift in hydrogen-like systems. This study examines the contribution of these processes to Lamb shift. It also provides the first ever derivation of renormalized terms of two-photon vacuum polarisation and self-energy vacuum polarisation. Until now it has only been possible to evaluate these contributions by way of an Uehling approximation [de

Time-resolved magnetic imaging in an aberration-corrected, energy-filtered photoemission electron microscope

International Nuclear Information System (INIS)

Nickel, F.; Gottlob, D.M.; Krug, I.P.; Doganay, H.; Cramm, S.; Kaiser, A.M.; Lin, G.; Makarov, D.; Schmidt, O.G.

2013-01-01

We report on the implementation and usage of a synchrotron-based time-resolving operation mode in an aberration-corrected, energy-filtered photoemission electron microscope. The setup consists of a new type of sample holder, which enables fast magnetization reversal of the sample by sub-ns pulses of up to 10 mT. Within the sample holder current pulses are generated by a fast avalanche photo diode and transformed into magnetic fields by means of a microstrip line. For more efficient use of the synchrotron time structure, we developed an electrostatic deflection gating mechanism capable of beam blanking within a few nanoseconds. This allows us to operate the setup in the hybrid bunch mode of the storage ring facility, selecting one or several bright singular light pulses which are temporally well-separated from the normal high-intensity multibunch pulse pattern. - Highlights: • A new time-resolving operation mode in photoemission electron microscopy is shown. • Our setup works within an energy-filtered, aberration-corrected PEEM. • A new gating system for bunch selection using synchrotron radiation is developed. • An alternative magnetic excitation system is developed. • First tr-imaging using an energy-filtered, aberration-corrected PEEM is shown

Spectral correction factors for conventional neutron dosemeters used in high-energy neutron environments

International Nuclear Information System (INIS)

Lee, K.W.; Sheu, R.J.

2015-01-01

High-energy neutrons (>10 MeV) contribute substantially to the dose fraction but result in only a small or negligible response in most conventional moderated-type neutron detectors. Neutron dosemeters used for radiation protection purpose are commonly calibrated with 252 Cf neutron sources and are used in various workplace. A workplace-specific correction factor is suggested. In this study, the effect of the neutron spectrum on the accuracy of dose measurements was investigated. A set of neutron spectra representing various neutron environments was selected to study the dose responses of a series of Bonner spheres, including standard and extended-range spheres. By comparing 252 Cf-calibrated dose responses with reference values based on fluence-to-dose conversion coefficients, this paper presents recommendations for neutron field characterisation and appropriate correction factors for responses of conventional neutron dosemeters used in environments with high-energy neutrons. The correction depends on the estimated percentage of high-energy neutrons in the spectrum or the ratio between the measured responses of two Bonner spheres (the 4P6-8 extended-range sphere versus the 6'' standard sphere). (authors)

Cointegration, error-correction, and the relationship between GDP and energy. The case of South Korea and Singapore

International Nuclear Information System (INIS)

Glasure, Yong U.; Lee, Aie-Rie

1998-01-01

This paper examines the causality issue between energy consumption and GDP for South Korea and Singapore, with the aid of cointegration and error-correction modeling. Results of the cointegration and error-correction models indicate bidirectional causality between GDP and energy consumption for both South Korea and Singapore. However, results of the standard Granger causality tests show no causal relationship between GDP and energy consumption for South Korea and unidirectional causal relationship from energy consumption to GDP for Singapore

Radon and the seal offered by the building shell

International Nuclear Information System (INIS)

Crameri, R.; Furrer, D.; Burkart, W.

1992-01-01

Long term measurements of the radon level before and after the building shell is sealed were carried out in 25 apartment buildings and 7 houses. The average values of the most important meteorological parameters of wind speed, external temperature and barometric pressure which may influence the radon level, were absolutely comparable during the measurement periods before and after the energy renovation of the buildings. Both in houses and in apartment buildings the radon level remained practically unchanged after the building shell was sealed. The lack of any increase in the radon level after reducing the air exchange rate can be explained by virtue of the fact that the balance between the infiltration and elimination of the radon before and after the energy renovation of the buildings remained unchanged. In addition to reducing the air exchange rate, sealing the building shell therefore also results in a reduction in radon infiltration from the soil. Although it is possible in certain cases for the radon level to increase after the building shell has been sealed, a general increase in radon levels inside living areas as a result of energy renovation work can be dismissed. 2 figs., 3 tabs., 30 refs

Development of stress correction formulae for heat formed steel plates

Directory of Open Access Journals (Sweden)

Hyung Kyun Lim

2018-03-01

Full Text Available The heating process such as line heating, triangular heating and so on is widely used in plate forming of shell plates found in bow and stern area of outer shell in a ship. Local shrinkage during heating process is main physical phenomenon used in plate forming process. As it is well appreciated, the heated plate undergoes the change in material and mechanical properties around heated area due to the harsh thermal process. It is, therefore, important to investigate the changes of physical and mechanical properties due to heating process in order to use them plate the design stage of shell plates. This study is concerned with the development of formula of plastic hardening constitutive equation for steel plate on which line heating is applied. In this study the stress correction formula for the heated plate has been developed based on the numerical simulation of tension test with varying plate thickness and heating speed through the regression analysis of multiple variable case. It has been seen the developed formula shows very good agreement with results of numerical simulation. This paper ends with usefulness of the present formula in examining the structural characteristic of ship's hull. Keywords: Heat input, Heat transfer analysis, Line heating, Shell plate, Stress correction, Thermo-elasto-plastic analysis

Irreversible thermodynamics of dark energy on the entropy-corrected apparent horizon

Energy Technology Data Exchange (ETDEWEB)

Karami, K; Sahraei, N [Department of Physics, University of Kurdistan, Pasdaran Street, Sanandaj (Iran, Islamic Republic of); Jamil, M, E-mail: KKarami@uok.ac.i, E-mail: mjamil@camp.nust.edu.p [Center for Advanced Mathematics and Physics (CAMP), National University of Sciences and Technology (NUST), Islamabad (Pakistan)

2010-10-15

We study the irreversible (non-equilibrium) thermodynamics of the Friedmann-Robertson-Walker (FRW) universe containing only dark energy. Using the modified entropy-area relation that is motivated by loop quantum gravity, we calculate the entropy-corrected form of the apparent horizon of the FRW universe.

Charge symmetry of the nuclear force as off-shell constraint

International Nuclear Information System (INIS)

Sauer, P.U.

1975-01-01

Off-shell changes are generated in the 1 S 0 nucleon-nucleon interaction using the Reid soft-core potential and unitary transformations of short range. Charge symmetry is assumed for the nuclear force. The same off-shell variations of the Reid potential are employed as the hadronic part of the proton-proton interaction and as neutron-neutron interaction. The Reid potential fits the experimental proton-proton data. It also accounts for the neutron-neutron scattering length with satisfying accuracy. The off-shell behavior of the Reid potential is varied in two different ways. First, off-shell changes consistent with the experimental proton-proton data can be selected. (auth) are performed which preserve the fit to the proton-proton data. Most transformed potentials of the type attempted here are unable to yield the correct experimental value of the neutron-neutron scattering length and have to be rejected. A simple practical rule is given according to which the off-shell changes consistent with the neutron-neutron scattering length can be selected. Second, off-shell changes are performed which leave the neutron-neutron scattering length unaltered. Transformed potentials of this type have usually been employed in nuclear-structure calculations. The potentials which exhibit large off-shell effects in nuclear structure are unable to account for the experimental proton-proton data. Their off-shell effects are therefore of no physical significance, and the potentials have to be rejected. A simple practical rule is given according to which the off-shell changes consistent with the experimental proton-proton data can be selected. (U.S.)

Energy transfers and magnetic energy growth in small-scale dynamo

KAUST Repository

Kumar, Rohit Raj; Verma, Mahendra K.; Samtaney, Ravi

2013-01-01

In this letter we investigate the dynamics of magnetic energy growth in small-scale dynamo by studying energy transfers, mainly energy fluxes and shell-to-shell energy transfers. We perform dynamo simulations for the magnetic Prandtl number Pm = 20

Running couplings and operator mixing in the gravitational corrections to coupling constants

International Nuclear Information System (INIS)

Anber, Mohamed M.; Donoghue, John F.; El-Houssieny, Mohamed

2011-01-01

The use of a running coupling constant in renormalizable theories is well known, but the implementation of this idea for effective field theories with a dimensional coupling constant is, in general, less useful. Nevertheless, there are multiple attempts to define running couplings, including the effects of gravity, with varying conclusions. We sort through many of the issues involved, most particularly the idea of operator mixing and also the kinematics of crossing, using calculations in Yukawa and λφ 4 theories as illustrative examples. We remain in the perturbative regime. In some theories with a high permutation symmetry, such as λφ 4 , a reasonable running coupling can be defined. However, in most cases, such as Yukawa and gauge theories, a running coupling fails to correctly account for the energy dependence of the interaction strength. As a by-product we also contrast on-shell and off-shell renormalization schemes and show that operators which are normally discarded, such as those that vanish by the equations of motion, are required for off-shell renormalization of effective field theories. Our results suggest that the inclusion of gravity in the running of couplings is not useful or universal in the description of physical processes.

Evolution of Structure in Nuclei: Meditation by Sub-Shell Modifications and Relation to Binding Energies

Science.gov (United States)

Casten, R. F.; Cakirli, R. B.

2009-03-01

Understanding the development of configuration mixing, coherence, collectivity, and deformation in nuclei is one of the crucial challenges in nuclear structure physics, and one which has become all the more important with the advent of next generation facilities for the study of exotic nuclei. We will discuss recent work on phase/shape transitional behavior in nuclei, and the role of changes in sub-shell structure in mediating such transitional regions. We will also discuss a newly found, much deeper, link between nuclear structure and nuclear binding energies.

Off-Shell Higgs Probe of Naturalness

Science.gov (United States)

Gonçalves, Dorival; Han, Tao; Mukhopadhyay, Satyanarayan

2018-03-01

Examining the Higgs sector at high energy scales through off-shell Higgs production can potentially shed light on the naturalness problem of the Higgs boson mass. We propose such a study at the LHC by utilizing a representative model with a new scalar field (S ) coupled to the standard model Higgs doublet (H ) in a form |S |2|H |2. In the process p p →h*→Z Z , the dominant momentum-dependent part of the one-loop scalar singlet corrections, especially above the new threshold at 2 mS, leads to a measurable deviation in the differential distribution of the Z -pair invariant mass, in accordance with the quadratic divergence cancellation to the Higgs mass. We find that it is conceivable to probe such new physics at the 5 σ level at the high-luminosity LHC, improving further with the upgraded 27 TeV LHC, without requiring the precise measurement of the Higgs boson total width. The discovery of such a Higgs portal could also have important implications for thermal dark matter as well as for electroweak baryogenesis.

Next-to-soft corrections to high energy scattering in QCD and gravity

Energy Technology Data Exchange (ETDEWEB)

Luna, A.; Melville, S. [SUPA, School of Physics and Astronomy, University of Glasgow,Glasgow G12 8QQ, Scotland (United Kingdom); Naculich, S.G. [Department of Physics, Bowdoin College,Brunswick, ME 04011 (United States); White, C.D. [Centre for Research in String Theory, School of Physics and Astronomy,Queen Mary University of London,327 Mile End Road, London E1 4NS (United Kingdom)

2017-01-12

We examine the Regge (high energy) limit of 4-point scattering in both QCD and gravity, using recently developed techniques to systematically compute all corrections up to next-to-leading power in the exchanged momentum i.e. beyond the eikonal approximation. We consider the situation of two scalar particles of arbitrary mass, thus generalising previous calculations in the literature. In QCD, our calculation describes power-suppressed corrections to the Reggeisation of the gluon. In gravity, we confirm a previous conjecture that next-to-soft corrections correspond to two independent deflection angles for the incoming particles. Our calculations in QCD and gravity are consistent with the well-known double copy relating amplitudes in the two theories.

Stability of Brans-Dicke thin-shell wormholes

Energy Technology Data Exchange (ETDEWEB)

Yue, Xiaojun, E-mail: yuexiaojun@mail.bnu.edu.cn [Department of Physics, Beijing Normal University, Beijing 100875 (China); Gao, Sijie, E-mail: sijie@bnu.edu.cn [Department of Physics, Beijing Normal University, Beijing 100875 (China)

2011-06-06

Recently, a class of spherically symmetric thin-shell wormholes in Brans-Dicke gravity have been introduced. Such wormholes can be supported by matter satisfying the weak energy condition (WEC). In this Letter, we first obtain all the exact solutions satisfying the WEC. Then we show these solutions can be stable for certain parameters. A general requirement for stability is that β{sup 2}>1, which may imply that the speed of sound exceeds the speed of light. -- Highlights: → Brans-Dicke thin-shell wormholes can be stable and satisfy the energy condition. → Solutions exist for ω<-2. → The speed of sound in the matter exceeds the speed of light.

Briquetting of Palm Kernel Shell | Ugwu | Journal of Applied ...

African Journals Online (AJOL)

In several developing countries, briquettes from agricultural residues contribute significantly to the energy mix especially for small scale and household requirements. In this work, briquettes were produced from Palm kernel shell. This was achieved by carbonising the shell to get the charcoal followed by the pulverization of ...

Shell-model predictions for Lambda Lambda hypernuclei

International Nuclear Information System (INIS)

Gal, A.; Millener, D.

2011-01-01

It is shown how the recent shell-model determination of ΛN spin-dependent interaction terms in Λ hypernuclei allows for a reliable deduction of ΛΛ separation energies in ΛΛ hypernuclei across the nuclear p shell. Comparison is made with the available data, highlighting # Lambda# # Lambda# 11 Be and # Lambda# # Lambda# 12 Be which have been suggested as possible candidates for the KEK-E373 HIDA event.

Effect of supercritical water shell on cavitation bubble dynamics

International Nuclear Information System (INIS)

Shao Wei-Hang; Chen Wei-Zhong

2015-01-01

Based on reported experimental data, a new model for single cavitation bubble dynamics is proposed considering a supercritical water (SCW) shell surrounding the bubble. Theoretical investigations show that the SCW shell apparently slows down the oscillation of the bubble and cools the gas temperature inside the collapsing bubble. Furthermore, the model is simplified to a Rayleigh–Plesset-like equation for a thin SCW shell. The dependence of the bubble dynamics on the thickness and density of the SCW shell is studied. The results show the bubble dynamics depends on the thickness but is insensitive to the density of the SCW shell. The thicker the SCW shell is, the smaller are the wall velocity and the gas temperature in the bubble. In the authors’ opinion, the SCW shell works as a buffering agent. In collapsing, it is compressed to absorb a good deal of the work transformed into the bubble internal energy during bubble collapse so that it weakens the bubble oscillations. (paper)

Multidimensional Analysis of Direct-Drive Plastic-Shell Implosions on OMEGA

Science.gov (United States)

Radha, P. B.

2004-11-01

Direct-drive implosions of plastic shells with the OMEGA laser are used as energy-scaled warm surrogates for ignition cryogenic targets designed for use on the National Ignition Facility. Plastic targets involve varying shell thickness (15 to 33 μm), fill pressures (3 to 15 atm), and shell adiabats. The multidimensional hydrodynamics code DRACO is used to evaluate the effects of capsule-surface roughness and illumination nonuniformities on target performance. These simulations indicate that shell stability during the acceleration phase plays a critical role in determining fusion yields. For shells that are thick enough to survive the Rayleigh--Taylor growth, target yields are significantly reduced by growth of the long (ℓ surrogacy between these plastic-shell implosions and the cryogenic ignition designs.

Charged shells in Lovelock gravity: Hamiltonian treatment and physical implications

International Nuclear Information System (INIS)

Dias, Goncalo A. S.; Gao, Sijie; Lemos, Jose P. S.

2007-01-01

interior, it is proved that the cosmic censorship is definitely upheld. Physical implications of the dynamics of such shells in a large extra dimension world scenario are also drawn. One concludes that, if such a large extra dimension scenario is correct, one can extract enough information from the outcome of those collisions as to know, not only the actual dimension of spacetime, but also which particular Lovelock gravity, general relativity or any other, is the correct one at these scales, in brief, to know d and k

Core-shell magnetic nanowires fabrication and characterization

Energy Technology Data Exchange (ETDEWEB)

Kalska-Szostko, B., E-mail: kalska@uwb.edu.pl [Institute of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok (Poland); Faculty of Physics, University of Bialystok, Ciolkowskiego 1L, 15-245 Bialystok, Poland (Poland); Klekotka, U.; Satuła, D. [Institute of Chemistry, University of Bialystok, Ciolkowskiego 1K, 15-245 Bialystok (Poland); Faculty of Physics, University of Bialystok, Ciolkowskiego 1L, 15-245 Bialystok, Poland (Poland)

2017-02-28

Highlights: • New approach for nanowires modification are presented. • Physical and chemical characterization of the nanowires are shown. • Properties modulations as an effect of the surface layer composition are discussed. - Abstract: In this paper, a new way of the preparation of core-shell magnetic nanowires has been proposed. For the modification Fe nanowires were prepared by electrodeposition in anodic aluminium oxide matrixes, in first step. In second, by wetting chemical deposition, shell layers of Ag, Au or Cu were obtained. Resultant core-shell nanowires structure was characterized by X-ray diffraction, infrared spectroscopy, transmission electron microscopy, and energy dispersive x-ray. Whereas magnetic properties by Mössbauer spectroscopy.

Development of an Energy Biorefinery Model for Chestnut (Castanea sativa Mill. Shells

Directory of Open Access Journals (Sweden)

Alessandra Morana

2017-09-01

Full Text Available Chestnut shells (CS are an agronomic waste generated from the peeling process of the chestnut fruit, which contain 2.7–5.2% (w/w phenolic compounds and approximately 36% (w/w polysaccharides. In contrast with current shell waste burning practices, this study proposes a CS biorefinery that integrates biomass pretreatment, recovery of bioactive molecules, and bioconversion of the lignocellulosic hydrolyzate, while optimizing materials reuse. The CS delignification and saccharification produced a crude hydrolyzate with 12.9 g/L of glucose and xylose, and 682 mg/L of gallic acid equivalents. The detoxification of the crude CS hydrolyzate with 5% (w/v activated charcoal (AC and repeated adsorption, desorption and AC reuse enabled 70.3% (w/w of phenolic compounds recovery, whilst simultaneously retaining the soluble sugars in the detoxified hydrolyzate. The phenols radical scavenging activity (RSA of the first AC eluate reached 51.8 ± 1.6%, which is significantly higher than that of the crude CS hydrolyzate (21.0 ± 1.1%. The fermentation of the detoxified hydrolyzate by C. butyricum produced 10.7 ± 0.2 mM butyrate and 63.9 mL H2/g of CS. Based on the obtained results, the CS biorefinery integrating two energy products (H2 and calorific power from spent CS, two bioproducts (phenolic compounds and butyrate and one material reuse (AC reuse constitutes a valuable upgrading approach for this yet unexploited waste biomass.

Ag/Au/Polypyrrole Core-shell Nanowire Network for Transparent, Stretchable and Flexible Supercapacitor in Wearable Energy Devices

Science.gov (United States)

Moon, Hyunjin; Lee, Habeom; Kwon, Jinhyeong; Suh, Young Duk; Kim, Dong Kwan; Ha, Inho; Yeo, Junyeob; Hong, Sukjoon; Ko, Seung Hwan

2017-02-01

Transparent and stretchable energy storage devices have attracted significant interest due to their potential to be applied to biocompatible and wearable electronics. Supercapacitors that use the reversible faradaic redox reaction of conducting polymer have a higher specific capacitance as compared with electrical double-layer capacitors. Typically, the conducting polymer electrode is fabricated through direct electropolymerization on the current collector. However, no research have been conducted on metal nanowires as current collectors for the direct electropolymerization, even though the metal nanowire network structure has proven to be superior as a transparent, flexible, and stretchable electrode platform because the conducting polymer’s redox potential for polymerization is higher than that of widely studied metal nanowires such as silver and copper. In this study, we demonstrated a highly transparent and stretchable supercapacitor by developing Ag/Au/Polypyrrole core-shell nanowire networks as electrode by coating the surface of Ag NWs with a thin layer of gold, which provide higher redox potential than the electropolymerizable monomer. The Ag/Au/Polypyrrole core-shell nanowire networks demonstrated superior mechanical stability under various mechanical bending and stretching. In addition, proposed supercapacitors showed fine optical transmittance together with fivefold improved areal capacitance compared to pristine Ag/Au core-shell nanowire mesh-based supercapacitors.

Shell Venster

International Nuclear Information System (INIS)

De Wit, P.; Looijesteijn, B.; Regeer, B.; Stip, B.

1995-03-01

In the bi-monthly issues of 'Shell Venster' (window on Shell) attention is paid to the activities of the multinational petroleum company Shell Nederland and the Koninklijke/Shell Groep by means of non-specialist articles

Running coupling corrections to high energy inclusive gluon production

International Nuclear Information System (INIS)

Horowitz, W.A.; Kovchegov, Yuri V.

2011-01-01

We calculate running coupling corrections for the lowest-order gluon production cross section in high energy hadronic and nuclear scattering using the BLM scale-setting prescription. In the final answer for the cross section the three powers of fixed coupling are replaced by seven factors of running coupling, five in the numerator and two in the denominator, forming a 'septumvirate' of running couplings, analogous to the 'triumvirate' of running couplings found earlier for the small-x BFKL/BK/JIMWLK evolution equations. It is interesting to note that the two running couplings in the denominator of the 'septumvirate' run with complex-valued momentum scales, which are complex conjugates of each other, such that the production cross section is indeed real. We use our lowest-order result to conjecture how running coupling corrections may enter the full fixed-coupling k T -factorization formula for gluon production which includes nonlinear small-x evolution.

Ambiguity in determining the effective action for string-corrected Einstein gravity

International Nuclear Information System (INIS)

Hochberg, D.; Shimada, T.

1986-11-01

The authors attempt to clarify some issues dealing with the determination of some of the coefficients appearing in the low-energy gravitational effective action for closed strings. In particular, the coefficients of the Rsub(μv) 2 and R 2 terms of the quadratic curvature corrections to the Einstein-Hilbert action are shown not to be determined by matching the on-shell S-matrices of the effective theory with that of the string theories. The mechanism responsible for the ambiguity of these coefficients is revealed as a cancellation among the contact, exchange and point-insertion terms contributing to the tree S-matrix of the effective local theory. Although ghost poles will appear in the graviton propagator for general quadratic curvature corrections, the effective theory remains unitary. The manifest absence of ghosts is achieved by choosing the Gauss-Bonnet combination of quadratic curvature terms, but the string does not single out this combination over any other. (author)

Symmetry energies for A =24 and 48 and the USD and KB3 shell model Hamiltonians

Science.gov (United States)

Kingan, A.; Neergârd, K.; Zamick, L.

2017-12-01

Calculations in the sd and pf shells reported some time ago by Satuła et al. [Phys. Lett. B 407, 103 (1997), 10.1016/S0370-2693(97)00711-9] are redone for an extended analysis of the results. As in the original work, we do calculations for one mass number in each shell and consider in each case the sequence of lowest energies for isospins 0, 2, and 4, briefly the symmetry spectrum. Following further the original work, we study how this spectrum changes when parts of the two-nucleon interaction are turned off. The variation of its width is explored in detail. A differential combination ɛW of the three energies was taken in the original work as a measure of the so-called Wigner term in semiempirical mass formulas, and it was found to decrease drastically when the two-nucleon interaction in the channel of zero isospin is turned off. Our analysis shows that the width of the symmetry spectrum experiences an equally drastic decrease, which can be explained qualitatively in terms of schematic approximations. We therefore suggest that the decrease of ɛW be seen mainly as a side effect of a narrowing of the symmetry spectrum rather than an independent manifestation of the two-nucleon interaction in the channel of zero isospin.

Highly efficient photocatalytic conversion of solar energy to hydrogen by WO3/BiVO4 core-shell heterojunction nanorods

Science.gov (United States)

Kosar, Sonya; Pihosh, Yuriy; Bekarevich, Raman; Mitsuishi, Kazutaka; Mawatari, Kazuma; Kazoe, Yutaka; Kitamori, Takehiko; Tosa, Masahiro; Tarasov, Alexey B.; Goodilin, Eugene A.; Struk, Yaroslav M.; Kondo, Michio; Turkevych, Ivan

2018-04-01

Photocatalytic splitting of water under solar light has proved itself to be a promising approach toward the utilization of solar energy and the generation of environmentally friendly fuel in a form of hydrogen. In this work, we demonstrate highly efficient solar-to-hydrogen conversion efficiency of 7.7% by photovoltaic-photoelectrochemical (PV-PEC) device based on hybrid MAPbI3 perovskite PV cell and WO3/BiVO4 core-shell nanorods PEC cell tandem that utilizes spectral splitting approach. Although BiVO4 is characterized by intrinsically high recombination rate of photogenerated carriers, this is not an issue for WO3/BiVO4 core-shell nanorods, where highly conductive WO3 cores are combined with extremely thin absorber BiVO4 shell layer. Since the BiVO4 layer is thinner than the characteristic carrier diffusion length, the photogenerated charge carriers are separated at the WO3/BiVO4 heterojunction before their recombination. Also, such architecture provides sufficient optical thickness even for extremely thin BiVO4 layer due to efficient light trapping in the core-shell WO3/BiVO4 nanorods with high aspect ratio. We also demonstrate that the concept of fill factor can be used to compare I-V characteristics of different photoanodes regarding their optimization for PV/PEC tandem devices.

Shell model calculations for exotic nuclei

International Nuclear Information System (INIS)

Brown, B.A.; Wildenthal, B.H.

1991-01-01

A review of the shell-model approach to understanding the properties of light exotic nuclei is given. Binding energies including p and p-sd model spaces and sd and sd-pf model spaces; cross-shell excitations around 32 Mg, including weak-coupling aspects and mechanisms for lowering the ntw excitations; beta decay properties of neutron-rich sd model, of p-sd and sd-pf model spaces, of proton-rich sd model space; coulomb break-up cross sections are discussed. (G.P.) 76 refs.; 12 figs

On the Coulomb displacement energy

International Nuclear Information System (INIS)

Sato, H.

1976-01-01

The Coulomb displacement energies of the T=1/2 mirror nuclei (A=15,17,27,29,31,33,39 and 41) are re-examined with the best available HF wave functions (the DME and the Skyrme II interaction), with the inclusion of all electromagnetic corrections. The results are compared with the experimental s.p. charge dependent energies extracted from the experimental data taking into account admixtures of core-excitation corrections with the help of present shell-model and co-existence model calculations. Although the so-called Nolen-Schiffer anomaly is not removed by these improvements, it is found that the remaining observed anomalies in the ground states of s.p. and s.h. systems can be resolved with the introduction of a simple, phenomenological charge symmetry breaking nucleon-nucleon force. This force can also account for the observed anomalies in the higher excited s.p. states, while those of the deeper s.h. states need further explanation. (Auth.)

Search for a double-collision mechanism as a possible interpretation for ionization by low-energy light-ion impact

International Nuclear Information System (INIS)

Avaldi, L.; Magno, C.; Milazzo, M.; Rota, A.

1981-01-01

In a previous work the authors proposed, in the frame of the binary-encounter approximation (BEA) of the inner-shell atomic ionization by ion bombardment, a correction to the ion energy in order to account for the Coulomb repulsion by the atomic nucleus. Such corrected cross-section values numerically coincide with those of the PWBA model, but, as a consequence of the correction, they obtain a much higher-energy ionization threshold than the binding energy, which has no experimental evidence. In the present work it is shown that ionization below such a threshold can be explained by a double-collision mechanism which involves intermediate electron states and can directly be derived from the impulsive nature of the binary-collision model. Calculations have been performed by supposing a statistical independence between these two collisions. Relativistic corrections have not been taken into account. A remarkable agreement is obtained between the curves corresponding to single- and double-collision classical processes, since they match at the bombarding threshold ion energy. (author)

Scatter correction using a primary modulator for dual energy digital radiography: A Monte Carlo simulation study

Science.gov (United States)

Jo, Byung-Du; Lee, Young-Jin; Kim, Dae-Hong; Kim, Hee-Joung

2014-08-01

In conventional digital radiography (DR) using a dual energy subtraction technique, a significant fraction of the detected photons are scattered within the body, making up the scatter component. Scattered radiation can significantly deteriorate image quality in diagnostic X-ray imaging systems. Various methods of scatter correction, including both measurement- and non-measurement-based methods, have been proposed in the past. Both methods can reduce scatter artifacts in images. However, non-measurement-based methods require a homogeneous object and have insufficient scatter component correction. Therefore, we employed a measurement-based method to correct for the scatter component of inhomogeneous objects from dual energy DR (DEDR) images. We performed a simulation study using a Monte Carlo simulation with a primary modulator, which is a measurement-based method for the DEDR system. The primary modulator, which has a checkerboard pattern, was used to modulate the primary radiation. Cylindrical phantoms of variable size were used to quantify the imaging performance. For scatter estimates, we used discrete Fourier transform filtering, e.g., a Gaussian low-high pass filter with a cut-off frequency. The primary modulation method was evaluated using a cylindrical phantom in the DEDR system. The scatter components were accurately removed using a primary modulator. When the results acquired with scatter correction and without scatter correction were compared, the average contrast-to-noise ratio (CNR) with the correction was 1.35 times higher than that obtained without the correction, and the average root mean square error (RMSE) with the correction was 38.00% better than that without the correction. In the subtraction study, the average CNR with the correction was 2.04 (aluminum subtraction) and 1.38 (polymethyl methacrylate (PMMA) subtraction) times higher than that obtained without the correction. The analysis demonstrated the accuracy of the scatter correction and the

Effects of the microbubble shell physicochemical properties on ultrasound-mediated drug delivery to the brain.

Science.gov (United States)

Wu, Shih-Ying; Chen, Cherry C; Tung, Yao-Sheng; Olumolade, Oluyemi O; Konofagou, Elisa E

2015-08-28

Lipid-shelled microbubbles have been used in ultrasound-mediated drug delivery. The physicochemical properties of the microbubble shell could affect the delivery efficiency since they determine the microbubble mechanical properties, circulation persistence, and dissolution behavior during cavitation. Therefore, the aim of this study was to investigate the shell effects on drug delivery efficiency in the brain via blood-brain barrier (BBB) opening in vivo using monodisperse microbubbles with different phospholipid shell components. The physicochemical properties of the monolayer were varied by using phospholipids with different hydrophobic chain lengths (C16, C18, and C24). The dependence on the molecular size and acoustic energy (both pressure and pulse length) were investigated. Our results showed that a relatively small increase in the microbubble shell rigidity resulted in a significant increase in the delivery of 40-kDa dextran, especially at higher pressures. Smaller (3kDa) dextran did not show significant difference in the delivery amount, suggesting that the observed shell effect was molecular size-dependent. In studying the impact of acoustic energy on the shell effects, it was found that they occurred most significantly at pressures causing microbubble destruction (450kPa and 600kPa); by increasing the pulse length to deliver the 40-kDa dextran, the difference between C16 and C18 disappeared while C24 still achieved the highest delivery efficiency. These indicated that the acoustic energy could be used to modulate the shell effects. The acoustic cavitation emission revealed the physical mechanisms associated with different shells. Overall, lipid-shelled microbubbles with long hydrophobic chain length could achieve high delivery efficiency for larger molecules especially with high acoustic energy. Our study, for the first time, offered evidence directly linking the microbubble monolayer shell with their efficacy for drug delivery in vivo. Copyright © 2015

Fast Computation of Solvation Free Energies with Molecular Density Functional Theory: Thermodynamic-Ensemble Partial Molar Volume Corrections.

Science.gov (United States)

Sergiievskyi, Volodymyr P; Jeanmairet, Guillaume; Levesque, Maximilien; Borgis, Daniel

2014-06-05

Molecular density functional theory (MDFT) offers an efficient implicit-solvent method to estimate molecule solvation free-energies, whereas conserving a fully molecular representation of the solvent. Even within a second-order approximation for the free-energy functional, the so-called homogeneous reference fluid approximation, we show that the hydration free-energies computed for a data set of 500 organic compounds are of similar quality as those obtained from molecular dynamics free-energy perturbation simulations, with a computer cost reduced by 2-3 orders of magnitude. This requires to introduce the proper partial volume correction to transform the results from the grand canonical to the isobaric-isotherm ensemble that is pertinent to experiments. We show that this correction can be extended to 3D-RISM calculations, giving a sound theoretical justification to empirical partial molar volume corrections that have been proposed recently.

Experimental and Monte Carlo studies of fluence corrections for graphite calorimetry in low- and high-energy clinical proton beams

International Nuclear Information System (INIS)

Lourenço, Ana; Thomas, Russell; Bouchard, Hugo; Kacperek, Andrzej; Vondracek, Vladimir; Royle, Gary; Palmans, Hugo

2016-01-01

Purpose: The aim of this study was to determine fluence corrections necessary to convert absorbed dose to graphite, measured by graphite calorimetry, to absorbed dose to water. Fluence corrections were obtained from experiments and Monte Carlo simulations in low- and high-energy proton beams. Methods: Fluence corrections were calculated to account for the difference in fluence between water and graphite at equivalent depths. Measurements were performed with narrow proton beams. Plane-parallel-plate ionization chambers with a large collecting area compared to the beam diameter were used to intercept the whole beam. High- and low-energy proton beams were provided by a scanning and double scattering delivery system, respectively. A mathematical formalism was established to relate fluence corrections derived from Monte Carlo simulations, using the FLUKA code [A. Ferrari et al., “FLUKA: A multi-particle transport code,” in CERN 2005-10, INFN/TC 05/11, SLAC-R-773 (2005) and T. T. Böhlen et al., “The FLUKA Code: Developments and challenges for high energy and medical applications,” Nucl. Data Sheets 120, 211–214 (2014)], to partial fluence corrections measured experimentally. Results: A good agreement was found between the partial fluence corrections derived by Monte Carlo simulations and those determined experimentally. For a high-energy beam of 180 MeV, the fluence corrections from Monte Carlo simulations were found to increase from 0.99 to 1.04 with depth. In the case of a low-energy beam of 60 MeV, the magnitude of fluence corrections was approximately 0.99 at all depths when calculated in the sensitive area of the chamber used in the experiments. Fluence correction calculations were also performed for a larger area and found to increase from 0.99 at the surface to 1.01 at greater depths. Conclusions: Fluence corrections obtained experimentally are partial fluence corrections because they account for differences in the primary and part of the secondary

Experimental and Monte Carlo studies of fluence corrections for graphite calorimetry in low- and high-energy clinical proton beams

Energy Technology Data Exchange (ETDEWEB)

Lourenço, Ana, E-mail: am.lourenco@ucl.ac.uk [Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom and Division of Acoustics and Ionising Radiation, National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Thomas, Russell; Bouchard, Hugo [Division of Acoustics and Ionising Radiation, National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Kacperek, Andrzej [National Eye Proton Therapy Centre, Clatterbridge Cancer Centre, Wirral CH63 4JY (United Kingdom); Vondracek, Vladimir [Proton Therapy Center, Budinova 1a, Prague 8 CZ-180 00 (Czech Republic); Royle, Gary [Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT (United Kingdom); Palmans, Hugo [Division of Acoustics and Ionising Radiation, National Physical Laboratory, Teddington TW11 0LW, United Kingdom and Medical Physics Group, EBG MedAustron GmbH, A-2700 Wiener Neustadt (Austria)

2016-07-15

Purpose: The aim of this study was to determine fluence corrections necessary to convert absorbed dose to graphite, measured by graphite calorimetry, to absorbed dose to water. Fluence corrections were obtained from experiments and Monte Carlo simulations in low- and high-energy proton beams. Methods: Fluence corrections were calculated to account for the difference in fluence between water and graphite at equivalent depths. Measurements were performed with narrow proton beams. Plane-parallel-plate ionization chambers with a large collecting area compared to the beam diameter were used to intercept the whole beam. High- and low-energy proton beams were provided by a scanning and double scattering delivery system, respectively. A mathematical formalism was established to relate fluence corrections derived from Monte Carlo simulations, using the FLUKA code [A. Ferrari et al., “FLUKA: A multi-particle transport code,” in CERN 2005-10, INFN/TC 05/11, SLAC-R-773 (2005) and T. T. Böhlen et al., “The FLUKA Code: Developments and challenges for high energy and medical applications,” Nucl. Data Sheets 120, 211–214 (2014)], to partial fluence corrections measured experimentally. Results: A good agreement was found between the partial fluence corrections derived by Monte Carlo simulations and those determined experimentally. For a high-energy beam of 180 MeV, the fluence corrections from Monte Carlo simulations were found to increase from 0.99 to 1.04 with depth. In the case of a low-energy beam of 60 MeV, the magnitude of fluence corrections was approximately 0.99 at all depths when calculated in the sensitive area of the chamber used in the experiments. Fluence correction calculations were also performed for a larger area and found to increase from 0.99 at the surface to 1.01 at greater depths. Conclusions: Fluence corrections obtained experimentally are partial fluence corrections because they account for differences in the primary and part of the secondary

Synthesis and characterization of thermal energy storage microencapsulated n-dodecanol with acrylic polymer shell

International Nuclear Information System (INIS)

Ma, Yanjie; Zong, Jiwen; Li, Wei; Chen, Long; Tang, Xiaofen; Han, Na; Wang, Jianping; Zhang, Xingxiang

2015-01-01

Two kinds of (microencapsulated phase change materials) MicroPCMs with acrylic-based copolymer as shell and n-dodecanol as core were successfully fabricated via suspension-like polymerization and photo-induced microencapsulation, respectively. Morphology and core–shell structure were observed by (field emission scanning electron microscope) FE-SEM. Thermal properties of the microencapsulated n-dodecanol were investigated by (differential scanning calorimeter) DSC and (thermogravimetric analysis) TGA. The results indicate that the mass ratio of core to shell has great influence on the morphology, inner structure, microencapsulated efficiency and durability of the microcapsules. Besides, the effects of various solvents and UV irridiation time on the microcapsule surface were discussed as well. In the experiment carried out, metal-ion complexation was conducted by the reaction between Mn ion and carboxyl groups on copolymer shell to enhance the performance of the microcapsules with n-dodecanol encapsulated. As the results indicate, the physicochemical properties and thermal conductivity of the shell were improved after Mn ion complexation reaction. Supercooling phenomenon of n-dodecanol was depressed to some extent. In the end, the thermo-regulated fiber containing acrylic-based copolymer microcapsules was fabricated, and thermo-regulated performance test of the fiber was also conducted. - Graphical abstract: (a)∼(d) schematic diagram of microencapsulation and (e) microcapsule with core–shell structure. - Highlights: • Microencapsulated n-dodecanol with acrylic polymer shell. • Microencapsulated n-dodecanol was fabricated by photo-induced microencapsulation. • Acrylic-based copolymer microcapsules with manganese-ion complexation

Importance-truncated shell model for multi-shell valence spaces

Energy Technology Data Exchange (ETDEWEB)

Stumpf, Christina; Vobig, Klaus; Roth, Robert [Institut fuer Kernphysik, TU Darmstadt (Germany)

2016-07-01

The valence-space shell model is one of the work horses in nuclear structure theory. In traditional applications, shell-model calculations are carried out using effective interactions constructed in a phenomenological framework for rather small valence spaces, typically spanned by one major shell. We improve on this traditional approach addressing two main aspects. First, we use new effective interactions derived in an ab initio approach and, thus, establish a connection to the underlying nuclear interaction providing access to single- and multi-shell valence spaces. Second, we extend the shell model to larger valence spaces by applying an importance-truncation scheme based on a perturbative importance measure. In this way, we reduce the model space to the relevant basis states for the description of a few target eigenstates and solve the eigenvalue problem in this physics-driven truncated model space. In particular multi-shell valence spaces are not tractable otherwise. We combine the importance-truncated shell model with refined extrapolation schemes to approximately recover the exact result. We present first results obtained in the importance-truncated shell model with the newly derived ab initio effective interactions for multi-shell valence spaces, e.g., the sdpf shell.

Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell during initial stage of shell expansion

Directory of Open Access Journals (Sweden)

Astafyeva Liudmila

2011-01-01

Full Text Available Abstract Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell, created under laser heating of nanoparticle in water, were theoretically investigated. Vapor shell expansion leads to decreasing up to one to two orders of magnitude in comparison with initial values of scattering and extinction of the radiation with wavelengths 532 and 633 nm by system while shell radius is increased up to value of about two radii of nanoparticle. Subsequent increasing of shell radius more than two radii of nanoparticle leads to rise of scattering and extinction properties of system over initial values. The significant decrease of radiation scattering and extinction by system of nanoparticle-vapor shell can be used for experimental detection of the energy threshold of vapor shell formation and investigation of the first stages of its expansion. PACS: 42.62.BE. 78.67. BF

Testing refined shell-model interactions in the sd shell: Coulomb excitation of Na26

CERN Document Server

Siebeck, B; Blazhev, A; Reiter, P; Altenkirch, R; Bauer, C; Butler, P A; De Witte, H; Elseviers, J; Gaffney, L P; Hess, H; Huyse, M; Kröll, T; Lutter, R; Pakarinen, J; Pietralla, N; Radeck, F; Scheck, M; Schneiders, D; Sotty, C; Van Duppen, P; Vermeulen, M; Voulot, D; Warr, N; Wenander, F

2015-01-01

Background: Shell-model calculations crucially depend on the residual interaction used to approximate the nucleon-nucleon interaction. Recent improvements to the empirical universal sd interaction (USD) describing nuclei within the sd shell yielded two new interactions—USDA and USDB—causing changes in the theoretical description of these nuclei. Purpose: Transition matrix elements between excited states provide an excellent probe to examine the underlying shell structure. These observables provide a stringent test for the newly derived interactions. The nucleus Na26 with 7 valence neutrons and 3 valence protons outside the doubly-magic 16O core is used as a test case. Method: A radioactive beam experiment with Na26 (T1/2=1,07s) was performed at the REX-ISOLDE facility (CERN) using Coulomb excitation at safe energies below the Coulomb barrier. Scattered particles were detected with an annular Si detector in coincidence with γ rays observed by the segmented MINIBALL array. Coulomb excitation cross sections...

Comparing several boson mappings with the shell model

International Nuclear Information System (INIS)

Menezes, D.P.; Yoshinaga, Naotaka; Bonatsos, D.

1990-01-01

Boson mappings are an essential step in establishing a connection between the successful phenomenological interacting boson model and the shell model. The boson mapping developed by Bonatsos, Klein and Li is applied to a single j-shell and the resulting energy levels and E2 transitions are shown for a pairing plus quadrupole-quadrupole Hamiltonian. The results are compared to the exact shell model calculation, as well as to these obtained through use of the Otsuka-Arima-Iachello mapping and the Zirnbauer-Brink mapping. In all cases good results are obtained for the spherical and near-vibrational cases

An efficient shutter-less non-uniformity correction method for infrared focal plane arrays

Science.gov (United States)

Huang, Xiyan; Sui, Xiubao; Zhao, Yao

2017-02-01

The non-uniformity response in infrared focal plane array (IRFPA) detectors has a bad effect on images with fixed pattern noise. At present, it is common to use shutter to prevent from radiation of target and to update the parameters of non-uniformity correction in the infrared imaging system. The use of shutter causes "freezing" image. And inevitably, there exists the problems of the instability and reliability of system, power consumption, and concealment of infrared detection. In this paper, we present an efficient shutter-less non-uniformity correction (NUC) method for infrared focal plane arrays. The infrared imaging system can use the data gaining in thermostat to calculate the incident infrared radiation by shell real-timely. And the primary output of detector except the shell radiation can be corrected by the gain coefficient. This method has been tested in real infrared imaging system, reaching high correction level, reducing fixed pattern noise, adapting wide temperature range.

Self-energy correction to the hyperfine splitting for excited states

International Nuclear Information System (INIS)

Wundt, B. J.; Jentschura, U. D.

2011-01-01

The self-energy corrections to the hyperfine splitting is evaluated for higher excited states in hydrogenlike ions using an expansion in the binding parameter Zα, where Z is the nuclear-charge number and α is the fine-structure constant. We present analytic results for D, F, and G states, and for a number of highly excited Rydberg states, with principal quantum numbers in the range 13≤n≤16, and orbital angular momenta l=n-2 and l=n-1. A closed-form analytic expression is derived for the contribution of high-energy photons, valid for any state with l≥2 and arbitrary n, l, and total angular momentum j. The low-energy contributions are written in the form of generalized Bethe logarithms and evaluated for selected states.

Intruder states at the N=20 shell closure

International Nuclear Information System (INIS)

Heyde, K.

1991-01-01

It is indicated that mp-mh (multiple) excitations across closed shells can occur at low energy throughout the nuclear mass region. Besides the 4p-4h, 8p-8h configurations, that are deformed, coexisting low-lying excitations are mainly observed for light N=Z nuclei. A new class of 2p-2h intruder O + state is shown to exist in nuclei where a neutron excess is present. In the latter cases, the proton-neutron interaction energy between the excited 2p-2h configuration and the open shell accounts for a very specific mass dependence in the intruder excitation energy. The experimental evidence that corroborates the idea of intruder states will be given. (G.P.) 28 refs.; 13 figs

Multi-shell model of ion-induced nucleic acid condensation

Energy Technology Data Exchange (ETDEWEB)

Tolokh, Igor S. [Department of Computer Science, Virginia Tech, Blacksburg, Virginia 24061 (United States); Drozdetski, Aleksander V. [Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States); Pollack, Lois [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853-3501 (United States); Baker, Nathan A. [Advanced Computing, Mathematics, and Data Division, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912 (United States); Onufriev, Alexey V. [Department of Computer Science, Virginia Tech, Blacksburg, Virginia 24061 (United States); Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States)

2016-04-21

We present a semi-quantitative model of condensation of short nucleic acid (NA) duplexes induced by trivalent cobalt(III) hexammine (CoHex) ions. The model is based on partitioning of bound counterion distribution around single NA duplex into “external” and “internal” ion binding shells distinguished by the proximity to duplex helical axis. In the aggregated phase the shells overlap, which leads to significantly increased attraction of CoHex ions in these overlaps with the neighboring duplexes. The duplex aggregation free energy is decomposed into attractive and repulsive components in such a way that they can be represented by simple analytical expressions with parameters derived from molecular dynamic simulations and numerical solutions of Poisson equation. The attractive term depends on the fractions of bound ions in the overlapping shells and affinity of CoHex to the “external” shell of nearly neutralized duplex. The repulsive components of the free energy are duplex configurational entropy loss upon the aggregation and the electrostatic repulsion of the duplexes that remains after neutralization by bound CoHex ions. The estimates of the aggregation free energy are consistent with the experimental range of NA duplex condensation propensities, including the unusually poor condensation of RNA structures and subtle sequence effects upon DNA condensation. The model predicts that, in contrast to DNA, RNA duplexes may condense into tighter packed aggregates with a higher degree of duplex neutralization. An appreciable CoHex mediated RNA-RNA attraction requires closer inter-duplex separation to engage CoHex ions (bound mostly in the “internal” shell of RNA) into short-range attractive interactions. The model also predicts that longer NA fragments will condense more readily than shorter ones. The ability of this model to explain experimentally observed trends in NA condensation lends support to proposed NA condensation picture based on the multivalent �

Effect of scatter correction on quantification of myocardial SPECT and application to dual-energy acquisition using triple-energy window method

International Nuclear Information System (INIS)

Nakajima, Kenichi; Matsudaira, Masamichi; Yamada, Masato; Taki, Junichi; Tonami, Norihisa; Hisada, Kinichi

1995-01-01

Triple-energy window (TEW) method is a simple and practical approach for correcting Compton scatter in single-photon emission tracer studies. The fraction of scatter correction, with a point source or 30 ml-syringe placed under the camera, was measured by the TEW method. The scatter fraction was 55% for 201 Tl, 29% for 99m Tc and 57% for 123 I. Composite energy spectra were generated and separated by the TEW method. Combination of 99m Tc and 201 Tl was well separated, and 201 Tl and 123 I were separated within an error of 10%; whereas asymmetric photopeak energy window was necessary for separating 123 I and 99m Tc. By applying this method to myocardial SPECT study, the effect of scatter elimination was investigated in each myocardial wall by polar map and profile curve analysis. The effect of scatter was higher in the septum and the inferior wall. The count ratio relative to the anterior wall including scatter was 9% higher in 123 I, 7-8% higher in 99m Tc and 6% higher in 201 Tl. Apparent count loss after scatter correction was 30% for 123 I, 13% for 99m Tc and 38% for 201 Tl. Image contrast, as defined myocardium-to-left ventricular cavity count ratio, improved by scatter correction. Since the influence of Compton scatter was significant in cardiac planar and SPECT studies; the degree of scatter fraction should be kept in mind both in quantification and visual interpretation. (author)

Towards quantitative analysis of core-shell catalyst nano-particles by aberration corrected high angle annular dark field STEM and EDX

International Nuclear Information System (INIS)

Haibo, E; Nellist, P D; Lozano-Perez, S; Ozkaya, D

2010-01-01

Core-shell structured heterogeneous catalyst nano-particles offer the promise of more efficient precious metal usage and also novel functionalities but are as yet poorly characterised due to large compositional variations over short ranges. High angle annular dark field detector in a scanning transmission electron microscope is frequently used to image at high resolution because of its Z-contrast and incoherent imaging process, but generally little attention is paid to quantification. Energy dispersive X-ray analysis provides information on thickness and chemical composition and, used in conjunction with HAADF-STEM, aids interpretation of imaged nano-particles. We present important calibrations and initial data for truly quantitative high resolution analysis.

Research on neutron energy spectrum of the beryllium, iron and polyethylene shells assemblies injected by D-T neutron

International Nuclear Information System (INIS)

An, Li; Guo, Haiping; Wang, Xinhua

2009-04-01

To test a simulation code, the multi-shell assemblies were established, which were made of beryllium stainless steel and polyethylene from the interior to the outer. The symmetry axes are all in the line of the D + beam. The neutron energy spectra above 1 MeV were obtained in medium by the detector of stilbene crystal of φ18 min x 20 mm. The distance between source and the spherical surface was 30 cm and 50 cm. The measurement channels are in the angle 0 degree and 120 degree relative to D + beam direction. The measurement positions are 0 cm, 9.7 cm, 12.8 cm and 17.3 cm away from the center of the assembly in both directions. The spectrum in different positions of the multi-shell assemblies in medium were compared and analyzed. (authors)

Restricted open-shell Kohn-Sham theory: N unpaired electrons

International Nuclear Information System (INIS)

Schulte, Marius; Frank, Irmgard

2010-01-01

Graphical abstract: High-spin or low-spin? The lowest-lying states for different multiplicities of iron complexes are described with a combination of restricted open-shell Kohn-Sham theory and Car-Parrinello molecular dynamics. - Abstract: We present an energy expression for restricted open-shell Kohn-Sham theory for N unpaired electrons. It is shown that it is possible to derive an explicit energy expression for all low-spin multiplets of systems that exhibit neither radial nor cylindrical symmetry. The approach was implemented in the CPMD code and tested for iron complexes.

The problems concerning the integration of very thin mirror shells

Science.gov (United States)

Basso, S.; Citterio, O.; Mazzoleni, F.; Pareschi, G.; Tagliaferri, G.; Valtolina, R.; Conconi, P.; Parodi, G.

2009-08-01

The necessity to reduce the mass and to increase the collecting area requires that the thickness of the optics becomes more and more thinner. Simbol-X was a typical example of this trend. Such thickness makes the shells floppy and therefore unable to maintain the correct shape. During the integration of the shells into the mechanical structure, only negligible deformation must be introduced. The low thickness means also that the shells must be glued on both sides to reach a good stiffness of the whole mirror module and this fact introduces a set of mounting problems. In INAF - Osservatorio Astronomico di Brera an integration process has been developed. The use of stiffening rings and of a temporary structure is the key to maintain the right shape of the shell. In this article the results of the integration of the first three prototypes of the Simbol-X optics are presented. The description of the process and the analysis of the degradation of the performances during the integration are shown in detail.

Sexual dimorphism in shells of Cochlostoma septemspirale (Caenogastropoda, Cyclophoroidea, Diplommatinidae, Cochlostomatinae

Directory of Open Access Journals (Sweden)

Fabian Reichenbach

2012-07-01

Full Text Available Sexual dimorphisms in shell-bearing snails expressed by characteristic traits of their respective shells would offer the possibility for a lot of studies about gender distribution in populations, species, etc. In this study, the seven main shell characters of the snail Cochlostoma septemspirale were measured in both sexes: (1 height and (2 width of the shell, (3 height and (4 width of the aperture, (5 width of the last whorl, (6 rib density on the last whorl, and (7 intensity of the reddish or brown pigments forming three bands over the shell. The variation of size and shape was explored with statistical methods adapted to principal components analysis (PCA and linear discriminant analysis (LDA. In particular, we applied some multivariate morphometric tools for the analysis of ratios that have been developed only recently, that is, the PCA ratio spectrum, allometry ratio spectrum, and LDA ratio extractor. The overall separation of the two sexes was tested with LDA cross validation.The results show that there is a sexual dimorphism in the size and shape of shells. Females are more slender than males and are characterised by larger size, a slightly reduced aperture height but larger shell height and whorl width. Therefore they have a considerable larger shell volume (about one fifth in the part above the aperture. Furthermore, the last whorl of females is slightly less strongly pigmented and mean rib density slightly higher. All characters overlap quite considerably between sexes. However, by using cross validation based on the 5 continuous shell characters more than 90% of the shells can be correctly assigned to each sex.

Super-paramagnetic core-shell material with tunable magnetic behavior by regulating electron transfer efficiency and structure stability of the shell

Directory of Open Access Journals (Sweden)

Wenyan Zhang

Full Text Available In this work, a spherical nano core-shell material was constructed by encapsulating Fe3O4 microsphere into conductive polymer-metal composite shell. The Fe3O4 microspheres were fabricated by assembling large amounts of Fe3O4 nano-crystals, which endowed the microspheres with super-paramagnetic property and high saturation magnetization. The polymer-metal composite shell was constructed by inserting Pt nano-particles (NPs into the conductive polymer polypyrrole (PPy. As size and dispersion of the Pt NPs has an important influence on their surface area and surface energy, it was effective to enlarge the interface area between PPy and Pt NPs, enhance the electron transfer efficiency of PPy/Pt composite shell, and reinforced the shell’s structural stability just by tuning the size and dispersion of Pt NPs. Moreover, core-shell structure of the materials made it convenient to investigate the PPy/Pt shell’s shielding effect on the Fe3O4 core’s magnetic response to external magnetic fields. It was found that the saturation magnetization of Fe3O4/PPy/Pt core-shell material could be reduced by 20.5% by regulating the conductivity of the PPy/Pt shell. Keywords: Super-paramagnetic, Conductivity, Magnetic shielding, Structural stability

MicroShell Minimalist Shell for Xilinx Microprocessors

Science.gov (United States)

Werne, Thomas A.

2011-01-01

MicroShell is a lightweight shell environment for engineers and software developers working with embedded microprocessors in Xilinx FPGAs. (MicroShell has also been successfully ported to run on ARM Cortex-M1 microprocessors in Actel ProASIC3 FPGAs, but without project-integration support.) Micro Shell decreases the time spent performing initial tests of field-programmable gate array (FPGA) designs, simplifies running customizable one-time-only experiments, and provides a familiar-feeling command-line interface. The program comes with a collection of useful functions and enables the designer to add an unlimited number of custom commands, which are callable from the command-line. The commands are parameterizable (using the C-based command-line parameter idiom), so the designer can use one function to exercise hardware with different values. Also, since many hardware peripherals instantiated in FPGAs have reasonably simple register-mapped I/O interfaces, the engineer can edit and view hardware parameter settings at any time without stopping the processor. MicroShell comes with a set of support scripts that interface seamlessly with Xilinx's EDK tool. Adding an instance of MicroShell to a project is as simple as marking a check box in a library configuration dialog box and specifying a software project directory. The support scripts then examine the hardware design, build design-specific functions, conditionally include processor-specific functions, and complete the compilation process. For code-size constrained designs, most of the stock functionality can be excluded from the compiled library. When all of the configurable options are removed from the binary, MicroShell has an unoptimized memory footprint of about 4.8 kB and a size-optimized footprint of about 2.3 kB. Since MicroShell allows unfettered access to all processor-accessible memory locations, it is possible to perform live patching on a running system. This can be useful, for instance, if a bug is

Dual-energy digital mammography for calcification imaging: Scatter and nonuniformity corrections

International Nuclear Information System (INIS)

Kappadath, S. Cheenu; Shaw, Chris C.

2005-01-01

Mammographic images of small calcifications, which are often the earliest signs of breast cancer, can be obscured by overlapping fibroglandular tissue. We have developed and implemented a dual-energy digital mammography (DEDM) technique for calcification imaging under full-field imaging conditions using a commercially available aSi:H/CsI:Tl flat-panel based digital mammography system. The low- and high-energy images were combined using a nonlinear mapping function to cancel the tissue structures and generate the dual-energy (DE) calcification images. The total entrance-skin exposure and mean-glandular dose from the low- and high-energy images were constrained so that they were similar to screening-examination levels. To evaluate the DE calcification image, we designed a phantom using calcium carbonate crystals to simulate calcifications of various sizes (212-425 μm) overlaid with breast-tissue-equivalent material 5 cm thick with a continuously varying glandular-tissue ratio from 0% to 100%. We report on the effects of scatter radiation and nonuniformity in x-ray intensity and detector response on the DE calcification images. The nonuniformity was corrected by normalizing the low- and high-energy images with full-field reference images. Correction of scatter in the low- and high-energy images significantly reduced the background signal in the DE calcification image. Under the current implementation of DEDM, utilizing the mammography system and dose level tested, calcifications in the 300-355 μm size range were clearly visible in DE calcification images. Calcification threshold sizes decreased to the 250-280 μm size range when the visibility criteria were lowered to barely visible. Calcifications smaller than ∼250 μm were usually not visible in most cases. The visibility of calcifications with our DEDM imaging technique was limited by quantum noise, not system noise

Transfer of energy between a pair of molecules near a plasmonic core-shell nanoparticle: Tunability and sensing

Energy Technology Data Exchange (ETDEWEB)

Daneshfar, Nader, E-mail: ndaneshfar@gmail.com, E-mail: ndaneshfar@razi.ac.ir; Yavari, Asghar [Department of Physics, Razi University, Kermanshah (Iran, Islamic Republic of)

2016-05-15

Our model is applied to the calculation of interaction energy between a pair of dipolar molecules (point dipoles) in the vicinity of a nanoshell monomer with core-shell structure, based on the dipole quasi-electrostatic theory of classical electrodynamics and using the Drude and Maxwell-Garnett model. In other words, this work discusses the intermolecular energy transfer from a donor molecule to an acceptor molecule near a spherical nanoparticle that is important for practical applications like sensing. It is shown that the proximity of plasmonic nanoparticles can have a strong effect on the energy transfer between molecules. In addition to the influence of the size, composition, embedding medium, and the filling fraction of doped particles on the interaction energy, the contribution of the dipolar, quadrupolar, octupolar, hexadecapolar, triakontadipolar, and higher order multipole interactions is presented and analyzed. Briefly, we will show that it is possible to achieve enhanced energy transfer by manipulation of different parameters as mentioned above.

Exact two-loop vacuum polarization correction to the Lamb shift in hydrogenlike ions

International Nuclear Information System (INIS)

Plunien, G.; Beier, T.; Soff, G.

1998-01-01

We present a calculation scheme for the two-loop vacuum polarization correction of order α 2 to the Lamb shift of hydrogenlike high-Z atoms. The interaction with the external Coulomb field is taken into account to all orders in (Zα). By means of a modified potential approach the problem is reduced to the evaluation of effective one-loop vacuumpolarization potentials. An expression for the energy shift is deduced within the framework of partial wave decomposition performing appropriate subtractions. Exact results for the two-loop vacuum polarization contribution to the Lamb shift of K- and L-shell electron states in hydrogenlike lead and uranium are presented. (orig.)

Utilization possibilities of palm shell as a source of biomass energy in Malaysia by producing bio-oil in pyrolysis process

International Nuclear Information System (INIS)

Abnisa, Faisal; Daud, W.M.A. Wan; Husin, W.N.W.; Sahu, J.N.

2011-01-01

Agriculture residues such as palm shell are one of the biomass categories that can be utilized for conversion to bio-oil by using pyrolysis process. Palm shells were pyrolyzed in a fluidized-bed reactor at 400, 500, 600, 700 and 800 o C with N 2 as carrier gas at flow rate 1, 2, 3, 4 and 5 L/min. The objective of the present work is to determine the effects of temperature, flow rate of N 2 , particle size and reaction time on the optimization of production of renewable bio-oil from palm shell. According to this study the maximum yield of bio-oil (47.3 wt%) can be obtained, working at the medium level for the operation temperature (500 o C) and 2 L/min of N 2 flow rate at 60 min reaction time. Temperature is the most important factor, having a significant positive effect on yield product of bio-oil. The oil was characterized by Fourier Transform infra-red (FT-IR) spectroscopy and gas chromatography/mass spectrometry (GC-MS) techniques. -- Highlights: → This study reports the results of experimental investing of conversion palm shell into bio-oil by using pyrolysis and to find the optimum condition to produce the highest yield of bio-oil. → Several parameters which have effect to the process such as temperature, N 2 flow rate, reaction time and particle size is will be investigated in this study. → The outcome of this result will be important for abatement and control of increasingly waste palm shell storage problems any energy source to the world.

Experiment and Simulation Analysis on Noise Attenuation of Al/MF Cylindrical Shells

Directory of Open Access Journals (Sweden)

Bin Li

2017-01-01

Full Text Available For the issue concerning internal noise reduction of Al-made cylindrical shell structure, the noise control method of laying melamine foam (MF layer is adopted for in-shell noise attenuation experiments of Al and Al/MF cylindrical shells and corresponding internal noise response spectrograms are obtained. Based on the Virtual.Lab acoustics software, a finite element model is established for the analysis of noise in the Al/MF cylinder shell and numerical simulation computation is conducted for the acoustic mode and in-shell acoustic response; the correctness of the finite element model is verified via comparison with measured data. On this basis, influence rules of different MF laying rate and different laying thickness on acoustic cavity resonance response within the low and medium frequency range of 100–400 Hz are studied. It is indicated that noise reduction increases with MF laying rate, but the amplification decreases along with the rising of MF laying rate; noise reduction per unit thickness decreases with the increase of laying thickness, while noise reduction per unit area increases.

Parametric instability analysis of truncated conical shells using the Haar wavelet method

Science.gov (United States)

Dai, Qiyi; Cao, Qingjie

2018-05-01

In this paper, the Haar wavelet method is employed to analyze the parametric instability of truncated conical shells under static and time dependent periodic axial loads. The present work is based on the Love first-approximation theory for classical thin shells. The displacement field is expressed as the Haar wavelet series in the axial direction and trigonometric functions in the circumferential direction. Then the partial differential equations are reduced into a system of coupled Mathieu-type ordinary differential equations describing dynamic instability behavior of the shell. Using Bolotin's method, the first-order and second-order approximations of principal instability regions are determined. The correctness of present method is examined by comparing the results with those in the literature and very good agreement is observed. The difference between the first-order and second-order approximations of principal instability regions for tensile and compressive loads is also investigated. Finally, numerical results are presented to bring out the influences of various parameters like static load factors, boundary conditions and shell geometrical characteristics on the domains of parametric instability of conical shells.

Shell model calculations for stoichiometric Na β-alumina

International Nuclear Information System (INIS)

Wang, J.C.

1985-01-01

Walker and Catlow recently reported the results of their shell model calculations for the structure and transport of Na β-alumina (Naβ). The main computer programs used by Walker and Catlow for their calculations are PLUTO and HADES III. The latter, a recent version of HADES II written for cubic crystals, is believed to be applicable to defects in crystals of both cubic and hexagonal symmetry. PLUTO is usually used in calculating properties of perfect crystals before defects are introduced into the structure. Walker and Catlow claim that, in some respects, their models are superior to those of Wang et al. Yet, their results are quite different from those observed experimentally. In this work these differences are investigated by using a computer program designed to calculate lattice energies for s Naβ using the same shell model parameters adopted by Walker and Catlow. The core and shell positions of all ions, as well as the lattice parameters, were fully relaxed. The calculated energy difference between aBR and BR sites (0.33 eV) is about twice as large as that reported by Walker and Catlow. The present results also show that the relaxed oxygen ion positions next to the conduction plane in this case are displaced from their observed sites reported. When the core-shell spring constant of the oxygen ion was adjusted to minimize these displacements, the above-mentioned energy difference increased to about 0.56 eV. These results cast doubt on the fluid conduction plane structure suggested by Walker and Catlow and on the defect structure and activation energy obtained from their calculations

Gross shell structure at high spin in heavy nuclei

International Nuclear Information System (INIS)

Deleplanque, Marie-Agnes; Frauendorf, Stefan; Pashkevich, Vitaly V.; Chu, S.Y.; Unzhakova, Anja

2003-01-01

Experimental nuclear moments of inertia at high spins along the yrast line have been determined systematically and found to differ from the rigid-body values. The difference is attributed to shell effect and these have been calculated microscopically. The data and quantal calculations are interpreted by means of the semiclassical Periodic Orbit Theory. From this new perspective, features in the moments of inertia as a function of neutron number and spin, as well as their relation to the shell energies can be understood. Gross shell effects persist up to the highest angular momenta observed

Electronic structure of single- and multiple-shell carbon fullerenes

International Nuclear Information System (INIS)

Lin, Y.; Nori, F.

1994-01-01

We study the electronic states of giant single-shell and the recently discovered nested multiple-shell carbon fullerenes within the tight-binding approximation. We use two different approaches, one based on iterations and the other on symmetry, to obtain the π-state energy spectra of large fullerene cages: C 240 , C 540 , C 960 , C 1500 , C 2160 , and C 2940 . Our iteration technique reduces the size of the problem by more than one order of magnitude (factors of ∼12 and 20), while the symmetry-based approach reduces it by a factor of 10. We also find formulas for the highest occupied and lowest unoccupied molecular orbital energies of C 60n 2 fullerenes as a function of n, demonstrating a tendency towards a metallic regime for increasing n. For multiple-shell fullerenes, we analytically obtain the eigenvalues of the intershell interaction

Higher-order corrected Higgs bosons in FeynHiggs2.4

Indian Academy of Sciences (India)

treatment of loop-corrected Higgs-boson mass eigenstates as external (on-shell) or internal .... This gives rise to finite wave function normalization factors. [22]. .... The elements of Un can be interpreted as effective couplings of internal Higgs.

Axisymmetric vibrations of thin shells of revolution

International Nuclear Information System (INIS)

Suzuki, Katsuyoshi; Kikuchi, Norio; Kosawada, Tadashi; Takahashi, Shin

1983-01-01

The problem of free vibration of axisymmetric shells of revolution is important in connection with the design of pressure vessels, chemical equipment, aircrafts, structures and so on. In this study, the axisymmetrical vibration of a thin shell of revolution having a constant curvature in meridian direction was analyzed by thin shell theory. First, the Lagrangian during one period of the vibration of a shell of revolution was determined by the primary approximate theory of Love, and the vibration equations and boundary conditions were derived from its stopping condition. The vibration equations were strictly analyzed by using the series solution. The basic equations for the strain and strain energy of a shell were based on those of Novozhilov. As the examples of numerical calculation, the natural frequency and vibration mode of the symmetrical shells of revolution fixed at both ends and supported at both ends were determined, and their characteristics were clarified. The theory and the numerical calculation ore described. Especially in the frequency curves, the waving phenomena were observed frequently, which were not seen in non-axisymmetric vibration, accordingly also the vibration mode changed in complex state on the frequency curves of same order. The numerical calculation was carried out in the large computer center in Tohoku University. (Kako, I.)

Electrostatics-driven shape transitions in soft shells.

Science.gov (United States)

Jadhao, Vikram; Thomas, Creighton K; Olvera de la Cruz, Monica

2014-09-02

Manipulating the shape of nanoscale objects in a controllable fashion is at the heart of designing materials that act as building blocks for self-assembly or serve as targeted drug delivery carriers. Inducing shape deformations by controlling external parameters is also an important way of designing biomimetic membranes. In this paper, we demonstrate that electrostatics can be used as a tool to manipulate the shape of soft, closed membranes by tuning environmental conditions such as the electrolyte concentration in the medium. Using a molecular dynamics-based simulated annealing procedure, we investigate charged elastic shells that do not exchange material with their environment, such as elastic membranes formed in emulsions or synthetic nanocontainers. We find that by decreasing the salt concentration or increasing the total charge on the shell's surface, the spherical symmetry is broken, leading to the formation of ellipsoids, discs, and bowls. Shape changes are accompanied by a significant lowering of the electrostatic energy and a rise in the surface area of the shell. To substantiate our simulation findings, we show analytically that a uniformly charged disc has a lower Coulomb energy than a sphere of the same volume. Further, we test the robustness of our results by including the effects of charge renormalization in the analysis of the shape transitions and find the latter to be feasible for a wide range of shell volume fractions.

Hypersonic vibrations of Ag@SiO2 (cubic core)-shell nanospheres.

Science.gov (United States)

Sun, Jing Ya; Wang, Zhi Kui; Lim, Hock Siah; Ng, Ser Choon; Kuok, Meng Hau; Tran, Toan Trong; Lu, Xianmao

2010-12-28

The intriguing optical and catalytic properties of metal-silica core-shell nanoparticles, inherited from their plasmonic metallic cores together with the rich surface chemistry and increased stability offered by their silica shells, have enabled a wide variety of applications. In this work, we investigate the confined vibrational modes of a series of monodisperse Ag@SiO(2) (cubic core)-shell nanospheres synthesized using a modified Stöber sol-gel method. The particle-size dependence of their mode frequencies has been mapped by Brillouin light scattering, a powerful tool for probing hypersonic vibrations. Unlike the larger particles, the observed spheroidal-like mode frequencies of the smaller ones do not scale with inverse diameter. Interestingly, the onset of the deviation from this linearity occurs at a smaller particle size for higher-energy modes than for lower-energy ones. Finite element simulations show that the mode displacement profiles of the Ag@SiO(2) core-shells closely resemble those of a homogeneous SiO(2) sphere. Simulations have also been performed to ascertain the effects that the core shape and the relative hardness of the core and shell materials have on the vibrations of the core-shell as a whole. As the vibrational modes of a particle have a bearing on its thermal and mechanical properties, the findings would be of value in designing core-shell nanostructures with customized thermal and mechanical characteristics.

Fabrication of Ni@Ti core-shell nanoparticles by modified gas aggregation source

Science.gov (United States)

Hanuš, J.; Vaidulych, M.; Kylián, O.; Choukourov, A.; Kousal, J.; Khalakhan, I.; Cieslar, M.; Solař, P.; Biederman, H.

2017-11-01

Ni@Ti core-shell nanoparticles were prepared by a vacuum based method using the gas aggregation source (GAS) of nanoparticles. Ni nanoparticles fabricated in the GAS were afterwards coated by a Ti shell. The Ti shell was deposited by means of magnetron sputtering. The Ni nanoparticles were decelerated in the vicinity of the magnetron to the Ar drift velocity in the second deposition chamber. X-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy analysis of the nanoparticles showed the core-shell structure. It was shown that the thickness of the shell can be easily tuned by the process parameters with a maximum achieved thickness of the Ti shell ~2.5 nm. The core-shell structure was confirmed by the STEM analysis of the particles.

Significant efficiency enhancement of hybrid solar cells using core-shell nanowire geometry for energy harvesting.

Science.gov (United States)

Tsai, Shin-Hung; Chang, Hung-Chih; Wang, Hsin-Hua; Chen, Szu-Ying; Lin, Chin-An; Chen, Show-An; Chueh, Yu-Lun; He, Jr-Hau

2011-12-27

A novel strategy employing core-shell nanowire arrays (NWAs) consisting of Si/regioregular poly(3-hexylthiophene) (P3HT) was demonstrated to facilitate efficient light harvesting and exciton dissociation/charge collection for hybrid solar cells (HSCs). We experimentally demonstrate broadband and omnidirectional light-harvesting characteristics of core-shell NWA HSCs due to their subwavelength features, further supported by the simulation based on finite-difference time domain analysis. Meanwhile, core-shell geometry of NWA HSCs guarantees efficient charge separation since the thickness of the P3HT shells is comparable to the exciton diffusion length. Consequently, core-shell HSCs exhibit a 61% improvement of short-circuit current for a conversion efficiency (η) enhancement of 31.1% as compared to the P3HT-infiltrated Si NWA HSCs with layers forming a flat air/polymer cell interface. The improvement of crystal quality of P3HT shells due to the formation of ordering structure at Si interfaces after air mass 1.5 global (AM 1.5G) illumination was confirmed by transmission electron microscopy and Raman spectroscopy. The core-shell geometry with the interfacial improvement by AM 1.5G illumination promotes more efficient exciton dissociation and charge separation, leading to η improvement (∼140.6%) due to the considerable increase in V(oc) from 257 to 346 mV, J(sc) from 11.7 to 18.9 mA/cm(2), and FF from 32.2 to 35.2%, which is not observed in conventional P3HT-infiltrated Si NWA HSCs. The stability of the Si/P3HT core-shell NWA HSCs in air ambient was carefully examined. The core-shell geometry should be applicable to many other material systems of solar cells and thus holds high potential in third-generation solar cells.

Analytic representation of the backscatter correction factor at the exit of high energy photon beams

International Nuclear Information System (INIS)

Kappas, K.; Rosenwald, J.C.

1991-01-01

In high-energy X-ray beams, the dose calculated near the exit surface under electronic equilibrium conditions is generally over-estimated since it is derived from measurements performed in water with large thickness of backscattering material. The resulting error depends on a number of parameters such as beam energy, field dimension, thickness of overlying and underlying material. The authors have systematically measured for 4 different energies and for different para- meters and for different combinations of the above parameters, the reduction of dose due to backscatter. This correction is expressed as a multiplicative factor, called 'Backscatter Correction Factor' (BCF). This BCF is larger for lower energies, larger field sizes and larger depths. The BCF has been represented by an analytical expression which involves an exponential function of the backscattering thickness and linear relationships with depth field size and beam quality index. Using this expression, the BCF can be calculated within 0.5% for any conditions in the energy range investigated. (author). 14 refs.; 4 figs.; 3 tabs

Optical properties of core-shell and multi-shell nanorods

Science.gov (United States)

Mokkath, Junais Habeeb; Shehata, Nader

2018-05-01

We report a first-principles time dependent density functional theory study of the optical response modulations in bimetallic core-shell (Na@Al and Al@Na) and multi-shell (Al@Na@Al@Na and Na@Al@Na@Al: concentric shells of Al and Na alternate) nanorods. All of the core-shell and multi-shell configurations display highly enhanced absorption intensity with respect to the pure Al and Na nanorods, showing sensitivity to both composition and chemical ordering. Remarkably large spectral intensity enhancements were found in a couple of core-shell configurations, indicative that optical response averaging based on the individual components can not be considered as true as always in the case of bimetallic core-shell nanorods. We believe that our theoretical results would be useful in promising applications depending on Aluminum-based plasmonic materials such as solar cells and sensors.

Wavefunction effects in inner shell ionization of light atoms by protons

International Nuclear Information System (INIS)

Aashamar, K.; Amundsen, P.A.

An efficient computer code for calculating the impact parameter distribution of atomic ionization probabilities caused by charged particle impact, has been developed. The programme is based on the semiclassical approximation, and it allows the use of an arbitrary atomic central potential for deriving the one-electron orbitals that form the basis for the description of the atomic states. Extensive calculations are reported for proton induced K-shell ionization in carbon and neon, covering energies in the range 0.1-10 MeV. Some calculations on proton-argon L-shell ionization are also reported. Comparison of the results obtained using (screened) hydrogenic potentials and the recently reported energy- optimized effective atomic central potentials, respectively demonstrates that wavefunction effects are generally important for inner-shell ionization of light atoms. The agreement between theory and experiment in the K-shell case is improved for fast collisions upon using better wavefunctions. (Auth.)

Off-shell T-matrices from inverse scattering

International Nuclear Information System (INIS)

Von Geramb, H.V.; Amos, K.A.

1989-01-01

Inverse scattering theory is used to determine local, energy independent, coordinate space nucleon-nucleon potentials. Inversions are made of phase shifts obtained by analyzes of data and from meson exchange theory, in particular the Paris and the Bonn parametrizations. Half off-shell T-matrices are generated to compare the exact meson theoretical results with those of inversion and it is found that phase equivalent interactions have essentially the same off-shell behaviour for any physically significant range of momenta. 8 refs., 8 figs

Relativistic Bose-Einstein condensates thin-shell wormholes

Science.gov (United States)

Richarte, M. G.; Salako, I. G.; Graça, J. P. Morais; Moradpour, H.; Övgün, Ali

2017-10-01

We construct traversable thin-shell wormholes which are asymptotically Ads/dS applying the cut and paste procedure for the case of an acoustic metric created by a relativistic Bose-Einstein condensate. We examine several definitions of the flare-out condition along with the violation or not of the energy conditions for such relativistic geometries. Under reasonable assumptions about the equation of state of the matter located at the shell, we concentrate on the mechanical stability of wormholes under radial perturbation preserving the original spherical symmetry. To do so, we consider linearized perturbations around static solutions. We obtain that dS acoustic wormholes remain stable under radial perturbations as long as they have small radius; such wormholes with finite radius do not violate the strong/null energy condition. Besides, we show that stable Ads wormhole satisfy some of the energy conditions whereas unstable Ads wormhole with large radii violate them.

SU-F-I-13: Correction Factor Computations for the NIST Ritz Free Air Chamber for Medium-Energy X Rays

International Nuclear Information System (INIS)

Bergstrom, P

2016-01-01

Purpose: The National Institute of Standards and Technology (NIST) uses 3 free-air chambers to establish primary standards for radiation dosimetry at x-ray energies. For medium-energy × rays, the Ritz free-air chamber is the main measurement device. In order to convert the charge or current collected by the chamber to the radiation quantities air kerma or air kerma rate, a number of correction factors specific to the chamber must be applied. Methods: We used the Monte Carlo codes EGSnrc and PENELOPE. Results: Among these correction factors are the diaphragm correction (which accounts for interactions of photons from the x-ray source in the beam-defining diaphragm of the chamber), the scatter correction (which accounts for the effects of photons scattered out of the primary beam), the electron-loss correction (which accounts for electrons that only partially expend their energy in the collection region), the fluorescence correction (which accounts for ionization due to reabsorption ffluorescence photons and the bremsstrahlung correction (which accounts for the reabsorption of bremsstrahlung photons). We have computed monoenergetic corrections for the NIST Ritz chamber for the 1 cm, 3 cm and 7 cm collection plates. Conclusion: We find good agreement with other’s results for the 7 cm plate. The data used to obtain these correction factors will be used to establish air kerma and it’s uncertainty in the standard NIST x-ray beams.

SU-F-I-13: Correction Factor Computations for the NIST Ritz Free Air Chamber for Medium-Energy X Rays

Energy Technology Data Exchange (ETDEWEB)

Bergstrom, P [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899 (United States)

2016-06-15

Purpose: The National Institute of Standards and Technology (NIST) uses 3 free-air chambers to establish primary standards for radiation dosimetry at x-ray energies. For medium-energy × rays, the Ritz free-air chamber is the main measurement device. In order to convert the charge or current collected by the chamber to the radiation quantities air kerma or air kerma rate, a number of correction factors specific to the chamber must be applied. Methods: We used the Monte Carlo codes EGSnrc and PENELOPE. Results: Among these correction factors are the diaphragm correction (which accounts for interactions of photons from the x-ray source in the beam-defining diaphragm of the chamber), the scatter correction (which accounts for the effects of photons scattered out of the primary beam), the electron-loss correction (which accounts for electrons that only partially expend their energy in the collection region), the fluorescence correction (which accounts for ionization due to reabsorption ffluorescence photons and the bremsstrahlung correction (which accounts for the reabsorption of bremsstrahlung photons). We have computed monoenergetic corrections for the NIST Ritz chamber for the 1 cm, 3 cm and 7 cm collection plates. Conclusion: We find good agreement with other’s results for the 7 cm plate. The data used to obtain these correction factors will be used to establish air kerma and it’s uncertainty in the standard NIST x-ray beams.

Indoor solar thermal energy saving time with phase change material in a horizontal shell and finned-tube heat exchanger.

Science.gov (United States)

Paria, S; Sarhan, A A D; Goodarzi, M S; Baradaran, S; Rahmanian, B; Yarmand, H; Alavi, M A; Kazi, S N; Metselaar, H S C

2015-01-01

An experimental as well as numerical investigation was conducted on the melting/solidification processes of a stationary phase change material (PCM) in a shell around a finned-tube heat exchanger system. The PCM was stored in the horizontal annular space between a shell and finned-tube where distilled water was employed as the heat transfer fluid (HTF). The focus of this study was on the behavior of PCM for storage (charging or melting) and removal (discharging or solidification), as well as the effect of flow rate on the charged and discharged solar thermal energy. The impact of the Reynolds number was determined and the results were compared with each other to reveal the changes in amount of stored thermal energy with the variation of heat transfer fluid flow rates. The results showed that, by increasing the Reynolds number from 1000 to 2000, the total melting time decreases by 58%. The process of solidification also will speed up with increasing Reynolds number in the discharging process. The results also indicated that the fluctuation of gradient temperature decreased and became smooth with increasing Reynolds number. As a result, by increasing the Reynolds number in the charging process, the theoretical efficiency rises.

Development of surrogate models using artificial neural network for building shell energy labelling

International Nuclear Information System (INIS)

Melo, A.P.; Cóstola, D.; Lamberts, R.; Hensen, J.L.M.

2014-01-01

Surrogate models are an important part of building energy labelling programs, but these models still present low accuracy, particularly in cooling-dominated climates. The objective of this study was to evaluate the feasibility of using an artificial neural network (ANN) to improve the accuracy of surrogate models for labelling purposes. An ANN was applied to model the building stock of a city in Brazil, based on the results of extensive simulations using the high-resolution building energy simulation program EnergyPlus. Sensitivity and uncertainty analyses were carried out to evaluate the behaviour of the ANN model, and the variations in the best and worst performance for several typologies were analysed in relation to variations in the input parameters and building characteristics. The results obtained indicate that an ANN can represent the interaction between input and output data for a vast and diverse building stock. Sensitivity analysis showed that no single input parameter can be identified as the main factor responsible for the building energy performance. The uncertainty associated with several parameters plays a major role in assessing building energy performance, together with the facade area and the shell-to-floor ratio. The results of this study may have a profound impact as ANNs could be applied in the future to define regulations in many countries, with positive effects on optimizing the energy consumption. - Highlights: • We model several typologies which have variation in input parameters. • We evaluate the accuracy of surrogate models for labelling purposes. • ANN is applied to model the building stock. • Uncertainty in building plays a major role in the building energy performance. • Results show that ANN could help to develop building energy labelling systems

Ni@Ru and NiCo@Ru Core-Shell Hexagonal Nanosandwiches with a Compositionally Tunable Core and a Regioselectively Grown Shell.

Science.gov (United States)

Hwang, Hyeyoun; Kwon, Taehyun; Kim, Ho Young; Park, Jongsik; Oh, Aram; Kim, Byeongyoon; Baik, Hionsuck; Joo, Sang Hoon; Lee, Kwangyeol

2018-01-01

The development of highly active electrocatalysts is crucial for the advancement of renewable energy conversion devices. The design of core-shell nanoparticle catalysts represents a promising approach to boost catalytic activity as well as save the use of expensive precious metals. Here, a simple, one-step synthetic route is reported to prepare hexagonal nanosandwich-shaped Ni@Ru core-shell nanoparticles (Ni@Ru HNS), in which Ru shell layers are overgrown in a regioselective manner on the top and bottom, and around the center section of a hexagonal Ni nanoplate core. Notably, the synthesis can be extended to NiCo@Ru core-shell nanoparticles with tunable core compositions (Ni 3 Co x @Ru HNS). Core-shell HNS structures show superior electrocatalytic activity for the oxygen evolution reaction (OER) to a commercial RuO 2 black catalyst, with their OER activity being dependent on their core compositions. The observed trend in OER activity is correlated to the population of Ru oxide (Ru 4+ ) species, which can be modulated by the core compositions. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Calculated L-shell x-ray line intensities for proton and helium ion impact

International Nuclear Information System (INIS)

Cohen, D.D.; Harrigan, M.

1986-01-01

Theoretical L-shell X-ray line intensities have been calculated for proton and helium bombardment of atoms from nickel (Z 2 = 28) to curium (Z 2 = 96). The ionization cross sections for the three L subshells were obtained from the recent calculations by Cohen and Harrigan in the ECPSSR theory, which uses the plane-wave Born approximation (PWBA) with corrections for energy loss (E), Coulomb deflection (C), perturbed-stationary-state (PSS), and relativistic (R) effects. The fluorescence yields and Coster-Kronig transition probabilities were taken from M. O. Krause (Phys. Chem. Ref. Data 8, 307 (1979)) and the L-subshell emission rates from S. I. Salem, S. L. Panosian, and R. A. Krause (Atomic Data and Nuclear Data Tables 14, 91 (1974)). The line intensities Ll, Lα, Leta, Lβ 1 to Lβ 6 , Lβ/sub 9,10/, and Lγ 1 to Lgg 6 are tabulated for selected ion energies from 0.2 to 10 MeV

K-shell x-ray production cross sections of selected elements Al to Ni for 4. 0 to 38. 0 MeV /sup 10/B ions. [Cross sections, 4. 0 to 38 MeV, binding energy, electron capture decay, PWBA, energy shifts, multiple ionization

Energy Technology Data Exchange (ETDEWEB)

Monigold, G.; McDaniel, F.D.; Duggan, J.L.; Mehta, R.; Rice, R.; Miller, P.D.

1976-01-01

K-Shell x-ray production cross sections for the target elements Sc, Ti, V, Mn, Fe, Co, and Ni were measured for incident /sup 10/B ions over the energy range 4.0 to 38.0 MeV. The cross section data were compared to the theoretical predictions of the binary encounter approximation (BEA); the plane wave born approximation (PWBA); and the PWBA modified to include corrections for increased binding energy (B), Coulomb deflection of the incident ion (C), orbital perturbation due to polarization (P), and relativistic effects (R). In addition, fluorescence yield variations (W/sub K/) and contributions to the cross sections from electron capture (EC) were included. It was found that the predictions of the fully modified PWBA with contributions from electron capture and fluorescence yield variations included provided the best fit to the experimental data over the entire energy range for each target element. The K..beta../K..cap alpha.. x-ray intensity ratios were compared to theoretical values that assume single hole ionization, and the x-ray energy shifts presented as a function of the energy of the incident ion. These two measurements provided confirmation of the occurrence of multiple ionization for /sup 10/B bombardment of target elements in the range 21 less than or equal to Z/sub 2/ less than or equal to 28.

FABRICATION OF GAS-FILLED TUNGSTEN-COATED GLASS SHELLS

International Nuclear Information System (INIS)

NIKROO, A; BAUGH, W; STEINMAN, D.A.

2003-09-01

OAK-B135 Deuterium (D 2 ) filled glass shells coated with a high Z element are needed for high energy density (HED) experiments by researchers at Los Alamos National Laboratory. They report here on our initial attempt to produce such shells. Glass shells made using the drop tower technique were coated with gold, palladium or tungsten, or a mixture of two of these elements. It was found that gold and palladium coatings did not stick well to the glass and resulted in poor or delaminated films. Tungsten coatings resulted in films suitable for these targets. Bouncing of shells during coating resulted in uniform tungsten coatings, but the surface of such coatings were filled with small nodules. Proper agitation of shells using a tapping technique resulted in smooth films with minimal particulate contamination. For coating rates of ∼ 0.15 (micro)m/hr coatings with ∼ 2 nm RMS surface finish could be deposited. The surface roughness of coatings at higher rates, 0.7 (micro)m/hr, was considerably worse (∼ 100 nm RMS). The columnar structure of the coatings allowed permeation filling of the tungsten coated glass shells with deuterium at 300 C

Theory of hydrogen shell flashes on accreting white dwarfs. II. The stable shell burning and the recurrence period of shell flashes

International Nuclear Information System (INIS)

Fujimoto, M.Y.

1982-01-01

By means of analytical solutions of the envelope, thermal properties of hydrogen shell burning on accreting white dwarfs are studied and a general picture for their progress is presented which is described by two parameters, the accretion rate and the mass of the white dwarf. On a white dwarf, the thermal behavior of gas in the burning shell depends on the configuration of the envelope, which gives birth to two distinct types of stable configurations in thermal equilibrium, a high and a low state. In the high state, the nuclear shell burning makes up for the energy loss from the surface. There exists the lower limit to the envelope mass for this state. The nuclear burning rate lies in a narrow range of about a factor of 2.5, irrespective of the mass of the white dwarf, while the range itself varies greatly with the latter. In the low state, the nuclear burning is extinct, and yet the compressional heating by accreted gas balances with the cooling through the diffusion of heat. Therefore, the structure depends on the accretion rate. Thermal instability of nuclear burning sets the upper limit to the envelope mass of this state

On Perturbation Solutions for Axisymmetric Bending Boundary Values of a Deep Thin Spherical Shell

Directory of Open Access Journals (Sweden)

Rong Xiao

2014-01-01

Full Text Available On the basis of the general theory of elastic thin shells and the Kirchhoff-Love hypothesis, a fundamental equation for a thin shell under the moment theory is established. In this study, the author derives Reissner’s equation with a transverse shear force Q1 and the displacement component w. These basic unknown quantities are derived considering the axisymmetry of the deep, thin spherical shell and manage to constitute a boundary value question of axisymmetric bending of the deep thin spherical shell under boundary conditions. The asymptotic solution is obtained by the composite expansion method. At the end of this paper, to prove the correctness and accuracy of the derivation, an example is given to compare the numerical solution by ANSYS and the perturbation solution. Meanwhile, the effects of material and geometric parameters on the nonlinear response of axisymmetric deep thin spherical shell under uniform external pressure are also analyzed in this paper.

Smart construction of polyaniline shell on cobalt oxides as integrated core-shell arrays for enhanced lithium ion batteries

International Nuclear Information System (INIS)

Qi, Meili; Xie, Dong; Zhong, Yu; Chen, Minghua; Xia, Xinhui

2017-01-01

Smart construction of advanced anode materials is extremely critical to develop high-performance lithium ion batteries. In this work, we have reported a facile strategy for fabricating Co 3 O 4 /polyaniline (PANI) core–shell arrays (CSAs) by chemical bath deposition (CBD) + electrodeposition methods Electrodeposited PANI shell is intimately decorated on the CBD-Co 3 O 4 nanorods forming composite CSAs. Highly conductive network and stress buffer layer are achieved with the aid of tailored PANI shell. Due to these advantages above, the designed Co 3 O 4 /PANI CSA S exhibit good electrochemical performance with higher reversible capacity (787 mAh g −1 ) and better cycle stability than the unmodified Co 3 O 4 counterpart. Our results show a new way for preparing advanced inorganic-organic composite electrodes for electrochemical energy storage.

Meson exchange current corrections to magnetic moments in quantum hadro-dynamics

Energy Technology Data Exchange (ETDEWEB)

Morse, T M; Price, C E; Shepard, J R [Colorado Univ., Boulder (USA). Dept. of Physics

1990-11-15

We have calculated pion exchange current corrections to the magnetic moments of closed shell {plus minus}1 particle nuclei near A=16 and 40 within the framework of quantum hadro-dynamics (QHD). We find that the correction is significant and that, in general, the agreement of the QHD isovector moments with experiment is worsened. Comparisons to previous non-relativistic calculations are also made. (orig.).

Hanford double shell tank corrosion monitoring instrument tree prototype

International Nuclear Information System (INIS)

Nelson, J.L.; Edgemon, G.L.; Ohl, P.C.

1995-11-01

High-level nuclear wastes at the Hanford site are stored underground in carbon steel double-shell and single-shell tanks (DSTs and SSTs). The installation of a prototype corrosion monitoring instrument tree into DST 241-A-101 was completed in December 1995. The instrument tree has the ability to detect and discriminate between uniform corrosion, pitting, and stress corrosion cracking (SCC) through the use of electrochemical noise measurements and a unique stressed element, three-electrode probe. The tree itself is constructed of AISI 304L stainless steel (UNS S30403), with probes in the vapor space, vapor/liquid interface and liquid. Successful development of these trees will allow their application to single shell tanks and the transfer of technology to other US Department of Energy (DOE) sites. Keywords: Hanford, radioactive waste, high-level waste tanks, electrochemical noise, probes, double-shell tanks, single-shell tanks, corrosion

A study on crosstalk correction in dual energy acquisition of 123I-MIBG and 201TlCl in myocardial SPECT

International Nuclear Information System (INIS)

Onoguchi, Masahisa; Satoh, Keiko; Murata, Hajime; Takao, Yuji; Ohtake, Eiji; Katoh, Kenichi; Saitoh, Kyoko; Toyama, Hinako; Ueno, Takashi.

1991-01-01

In the simultaneous dual energy acquisition, energy spectrums of two radionuclides crosstalk each other and this phenomenon is a cause of the poor quality of images. In order to obtain the image of high quality in dual energy acquisition of 123 I-MIBG and 201 TlCl, a crosstalk correction method was originated. The crosstalk from 201 Tl to 123 I window (RI) and the crosstalk from 123 I to 201 Tl window (R2) were determined by the cardiac phantom studies. R1 and R2 showed almost constant value throughout the myocardial wall. The crosstalk correction was performed using R1 and R2. After the crosstalk correction, the defect region placed in the cardiac phantom was detected more clearly both in visual interpretation and in quantitative analysis. The crosstalk correction method with R1 and R2 was applied to some clinical cases. By the crosstalk correction, the quality of image was improved and a false defect caused by crosstalk disappeared in a clinical case. The crosstalk correction was considered to be useful for improving the quality of image on dual energy acquisition. (author)

Wave Function Engineering in CdSe/PbS Core/Shell Quantum Dots.

Science.gov (United States)

Wieliczka, Brian M; Kaledin, Alexey L; Buhro, William E; Loomis, Richard A

2018-05-25

The synthesis of epitaxial CdSe/PbS core/shell quantum dots (QDs) is reported. The PbS shell grows in a rock salt structure on the zinc blende CdSe core, thereby creating a crystal structure mismatch through additive growth. Absorption and photoluminescence (PL) band edge features shift to lower energies with increasing shell thickness, but remain above the CdSe bulk band gap. Nevertheless, the profiles of the absorption spectra vary with shell growth, indicating that the overlap of the electron and hole wave functions is changing significantly. This leads to over an order of magnitude reduction of absorption near the band gap and a large, tunable energy shift, of up to 550 meV, between the onset of strong absorption and the band edge PL. While the bulk valence and conduction bands adopt an inverse type-I alignment, the observed spectroscopic behavior is consistent with a transition between quasi-type-I and quasi-type-II behavior depending on shell thickness. Three effective mass approximation models support this hypothesis and suggest that the large difference in effective masses between the core and shell results in hole localization in the CdSe core and a delocalization of the electron across the entire QD. These results show the tuning of wave functions and transition energies in CdSe/PbS nanoheterostructures with prospects for use in optoelectronic devices for luminescent solar concentration or multiexciton generation.

Preparation and characterization of antibacterial Au/C core-shell composite

Energy Technology Data Exchange (ETDEWEB)

Gao Yanhong [Department of Chemistry and Institute of Nanochemistry, Jinan University, 601 Huangpudadaoxi Road, Guangzhou 510632, Guangdong (China); Centers for Disease Control and Prevention of Guangdong Province, Guangzhou 510300, Guangdong (China); Zhang Nianchun [Department of Chemistry and Institute of Nanochemistry, Jinan University, 601 Huangpudadaoxi Road, Guangzhou 510632, Guangdong (China); Zhong Yuwen [Centers for Disease Control and Prevention of Guangdong Province, Guangzhou 510300, Guangdong (China); Cai Huaihong [Department of Chemistry and Institute of Nanochemistry, Jinan University, 601 Huangpudadaoxi Road, Guangzhou 510632, Guangdong (China); Liu Yingliang, E-mail: tliuyl@jnu.edu.cn [Department of Chemistry and Institute of Nanochemistry, Jinan University, 601 Huangpudadaoxi Road, Guangzhou 510632, Guangdong (China)

2010-09-01

An environment-friendly oxidation-reduction method was used to prepare Au/C core-shell composite using carbon as core and gold as shell. The chemical structures and morphologies of Au/C core-shell composite and carbon sphere were characterized by X-ray diffraction, transmission electron microscope, energy dispersion X-ray spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS). The antibacterial properties of the Au/C core-shell composite against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Candida albicans (C. albicans) were examined by the disk diffusion assay and minimal inhibition concentration (MIC) methods. In addition, antibacterial ability of Au/C core-shell composite was observed by atomic force microscope. Results demonstrated that gold homogeneously supported on the surface of carbon spheres without aggregation and showed efficient antibacterial abilities.

Shell closure in stable and unstable Fermion systems