bluuebunny/crossref_metadata_2025 huggingface dataset:
Triaxiality in 146,148Sm nuclei
Authors: Varshney A. K. , Gupta K. K. , Gupta D. K. , Tyagi R. K.
Published: April 2011

Recently, attempts have been made to use the dynamic pairing plus quadrupole model to evaluate B(E2) values, B(E2) branching ratios, and low-lying energy levels for 146,148Sm nuclei, which are in poor agreement with experiment. Application of the boson expansion technique on 148Sm shows too much splitting and an incorrect order for the quintet states, while other properties have not been discussed. In the present work, 146,148Sm nuclei have been described using an asymmetric rotor model framework. The nonaxiality parameter (γ) has been evaluated using the energy ratio E2+′/E6+. Remarkable success has been achieved in explaining the correct ordering of known low-lying energy levels, B(E2) values, and B(E2) branching ratios, which indicate that the so-called spherical nuclei may be treated as triaxial.
A re-investigation of the possibility of 1/f noise fluctuations in α decay
Authors: Pepper G. T. , Kennett T. J. , Prestwich W. V.
Published: April 2011

The fluctuations in counts observed for the α decay of 241Am have been analyzed for a possible 1/f component. The data indicate that if 1/f fluctuations exist, the associated flicker floor is probably less than 2 × 10−9.
A note on gravitational radiation
Authors: Wallace G.
Published: April 2011

In this note we investigate the energy loss of many-armed structures owing to the emission of quadrupole gravitational radiation. We find that for a structure with two symmetrically placed arms the energy loss is a maximum, while for three or more symmetrically placed arms the energy loss is zero. An asymmetry in the placement of the two arms is also considered.
Low-lying collective bands in the even tungsten isotopes 180–186W
Authors: Sahu R.
Published: April 2011

The γ-rigid model has been used to study the energy levels and the electromagnetic properties of 180, 182, 184, 186W. In this model, the intrinsic wave functions are obtained using the pairing plus the quadrupole–quadrupole interaction Hamiltonian of Baranger and Kumar. Good angular momentum states are projected approximately from such a triaxially symmetric intrinsic wave function. This model assumes the nucleus to be γ rigid but soft in the β degrees of freedom. The asymmetry parameter γ for a given nucleus is extracted using the experimental energies of the first 2+ and second 2+ states within the framework of the Davydov–Filippov model. The symmetry parameter β for each J state is determined from the minimization of the projected energy. The calculated energy levels of the ground and the 7 band, the B(E2) values, the electromagnetic moments, the E2 and E4 matrix elements, and the B(E2) ratios agree quite well with experimental results.
High-pressure nuclear quadrupolar resonance study of dynamical effects associated with the structural phase transition in K2OsCl6
Authors: Krupski Marcin , Armstrong Robin L.
Published: April 2011

A new design for a nuclear quadrupolar resonance probe to study solids subjected to high hydrostatic pressures at low temperatures is presented. Measurements of the 35Cl spin-lattice relaxation are reported at three pressures in the temperature range just above the structural phase transition in the antifluorite crystal K2OsCl6. These data are influenced by the softening of the rotary lattice mode and the evolution of a dynamic central peak. A small pressure dependence of the correlated fluctuations associated with the soft mode is observed; however no detectable effect on the correlated fluctuations associated with the dynamic disorder component of the central peak is seen.
General relativistic stability of Q matter with a SO(2) × SO(2) global symmetry
Authors: Wolf C.
Published: April 2011

An approximate solution is given for a SO(2) × SO(2) globally invariant theory in curved space. The mass of the configuration is computed and the domain of stability for small perturbations is examined.
A nuclear magnetic resonance study of 1H, 23Na, and 31P relaxation and molecular dynamics in the sodium salts of some pyrophosphates
Authors: Reynhardt E. C.
Published: April 2011

Proton second moments and spin-lattice relaxation times in the laboratory and rotating frames and 31P and 23Na spin-lattice relaxation times in the laboratory frame have been measured over the temperature region 295 > T > 100 K for the sodium pyrophosphate salts, Na2P2O7∙10H2O and Na2H2P2O7. Laboratory-frame 31P and 23Na spin-lattice relaxation times have also been measured over the same temperature range for Na4P2O7. In the case of Na4P2O7∙10H2O, the results show clearly that the H2O molecules execute a twofold jump motion at higher temperatures. The potential barriers to these motions range from 30 to 40 kJ/mol. The 31P and 23Na relaxations are also influenced by these motions. The [Formula: see text] ion in Na2H2P2O7 is stationary over the temperature range studied. T1(Na) is most probably dominated by acoustical lattice vibrations. The [Formula: see text] ion in Na4P2O7 is not involved in a molecular reorientation. A shallow T1(P) minimum of 55 s is associated with a limited motion of the pyrophosphate molecule.
Rototranslational absorption in gaseous H2–Ar mixtures at intermediate densities
Authors: Dore P. , Filabozzi A. , Birnbaum G.
Published: April 2011

We present the measurements and analysis of the density effects on the rototranslational absorption spectrum of H2–Ar mixtures, for densities up to about 200 amagat. This density range is intermediate between the low-density limit, in which the spectrum is due to binary interactions, and the high-density range, in which density produces the so-called density-narrowing effect, which was studied previously. We find in the density range currently explored that density (ρ) effects are clearly evident and are well accounted for by considering a negative ρ3 contribution to the absorption besides the dominant ρ2 contribution. Experimental values of the two-body and three-body zeroth moments are obtained. We also obtain experimental line profiles for these two contributions. Even if the accuracy of the ρ3 profile is low, this work presents the first ρ3 line determined from measurements of collision-induced absorption.
The four-gravitino tree amplitude in the superstring
Authors: Jeong Min Ho , Kim Jae Kwan
Published: April 2011

Using superconformal field theoretic methods, the tree amplitude for four massive gravitinos in the open ten-dimensional superstring is calculated. The amplitude is given in a manifestly Lorentz-covariant form.
Dependence of critical layer thickness on temperature for lattice-mismatched materials
Authors: Ji G. , Ristic V. M. , Reddy U. K.
Published: April 2011

The growth dynamics of dislocations in lattice-mismatched materials is explained by two consecutive processes. The first is dislocation creation and glide along the directions of close packing in the lattice. The second is the dislocation growth or climb process, which is perpendicular to the glide direction. The Matthews' formula for the critical layer thickness hc, [12], is a proper formula to predict the hc values in the first process. The strong temperature dependence of the second process explains the temperature dependence of critical layer thickness observed experimentally, since the climb process brings the dislocation from the interface through the layers.
Group structure of superluminal Lorentz transformations and their representation
Authors: Chandola H. C. , Rajput B. S.
Published: April 2011

Constructing the generalized superluminal Lorentz transformations for inertial frames with nonpreferred orientation, we have investigated their group theoretical and commutation properties. The extended homogeneous Lorentz group in terms of these transformations has been constructed and its generators have been derived; these have been shown to generate the ray representation of the resulting Poincaré group.
Tensor couplings in the nucleon–nucleon interaction
Authors: Ng Kim Kwee , Li Guang Lie
Published: April 2011

An alternate way has been found in which the relativistic couplings between the nucleons, through the exchanges of different mesons, may be calculated. Explicit expressions for various relativistic couplings and the fourth-order effect from the π mesons are derived and tabulated. Compact and simpler forms for different coupling mechanisms are readily obtained through the use of the tensor coupling technique described in the paper.
A study of open thick microstrip: the hybrid quasistatic approximation
Authors: Chryssomallis M. , Siakavara K. , Sahalos J. N.
Published: April 2011

In this paper we study microstrips with rectangular and rounded edge cross sections. A hybrid quasistatic method is applied and the effective permittivity and the attenuation constant of the microstrip are found. Instead of the dielectric constant of the substrate an ideational one is used that depends on the geometry and the frequency. The attenuation constant for the rectangular microstrip was found to be in good agreement with values given in the literature. A microstrip with a rounded edge cross section has a smaller attenuation constant due to the conductor than that of a microstrip with a rectangular crosssection. Thus, a rounded edge microstrip is preferred because it will give an appreciable effect in reducing the ohmic losses of the line.
Testing pseudofermion lattice QCD with small quark masses and large volumes
Authors: Campostrini M. , Moriarty K. J. M. , Potvin J. , Rebbi C.
Published: April 2011

We report on extensive tests done on the pseudofermion algorithm in a simulation of lattice QCD with dynamical quarks. These tests are carried out in a more realistic context than many of the studies previously attempted as a lattice volume of 103 × 32 sites and quark mass of about 50 to 200 MeV are used throughout the calculation. Wilson loop factors of various sizes, as well as chiral condensates and pion propagators, are shown to change by less than 5% when the pseudofermion algorithm is tuned to simulate QCD more accurately.
Black holes: the legacy of Hilbert's error
Authors: Abrams Leonard S.
Published: April 2011

The historical postulates for the point mass are shown to be satisfied by an infinity of space–times, differing as to the limiting acceleration of a radially approaching test particle. Taking this limit to be infinite gives Schwarzschild's result, which for a point mass at x = y = z = 0 has C(0 +) = α2, where α = 2m and C(r) denotes the coefficient of the angular terms in the polar form of the metric. Hilbert's derivation used the variable r* = [C(r)]1/2, which transforms the coordinate location of the point mass to [Formula: see text]. For Hilbert, however, C was unknown, and thus could not be used to determine [Formula: see text]. Instead he asserted, in effect, that r* = (x2 + y2 + z2)1/2, which places the point mass at r* = 0. Unfortunately, this differs from the value (α) obtained by substituting Schwarzschild's C into the expression for [Formula: see text], and since C(0 +) is a scalar invariant, it follows that Hilbert's assertion is invalid. Owing to this error, in each spatial section of Hilbert's space –time, the boundary (r* = α) corresponding to r = 0 is no longer a point, but a two-sphere. This renders his space–time analytically extendible, and as shown by Kruskal and Fronsdal, its maximal extension contains a black hole. Thus the Kruskal–Fronsdal black hole is merely an artifact of Hilbert's error.
Two simple geometrical interpretations of the relativistic transformations
Authors: Hillion Pierre
Published: April 2011

We illustrate the differences between the synchronous and the nonsynchronous interpretations of relativity on a system simple enough to make possible a geometrical picture of these two interpretations. We use a diagram similar to Minkowski's diagram.
Effet d'une pulvérisation de l'antimoine dans le a-Si: H
Authors: Diawara Y. , Currie J. F. , Gujrathi S. C. , Oxorn K.
Published: April 2011

Cathode-sputtering of antimony in a-Si:H yields an amorphous film more conductive than intrinsic a-Si:H. A rapid annealing of the film allows us to increase its conductivity and to observe a dehydrogenation by infrared absorption measurements and by the elastic recoil detection technique. The latter method also gave us a precise analysis of the chemical composition of the amorphous film.[Journal translation]
Study of correlation functions in molecular crystals
Authors: Wartak M. S. , Fong C. Y.
Published: April 2011

We have studied the correlation functions for a model Hamiltonian describing the vibrational properties in molecular crystals. The model Hamiltonian consists of terms characterizing the on-site anharmonicity and the nearest-neighbor hopping interaction. If the on-site anharmonicity is uniform, the correlation functions exhibit no structure. However, structure appears in the nearest-neighbor correlation function if the anharmonicity is nonuniform. Because the Hamiltonian resembles the Hubbard model for the electronic case, the implication of the results to high temperature superconductors is indicated.
Actions and propagators for massless Dirac fermion fields in two-dimensional space-time
Authors: Skinner Ray , Wong Ken
Published: April 2011

It is shown that it is necessary to add a boundary term to the conventional action for the Dirac fermion field. This is verified for massless fermions in a two-dimensional space–time by exact calculations of the path integrals for various transition amplitudes over a finite time interval.
A 1++ partial wave exists in two-gluon and (or) photon fermion pair transmutation
Authors: Roberts Winston
Published: April 2011

Arguments based on unitarity and analyticity suggest that there is no 1++ partial wave in a process such as e+e− 1 γγ 1 μ+μ−. This note demonstrates that, in fact, such a partial wave does exist. Reasons for the apparent breakdown of traditional arguments are briefly discussed.
Mapping the axial current onto the hypersphere
Authors: McKeon D. G. C.
Published: April 2011

A stereographic projection has been used to map conformally invariant spinor electrodynamics from four-dimensional Euclidean space onto the surface of a sphere in five dimensions. We extend electrodynamics so that the spinors also couple in a gauge invariant way to the current on the surface of the hypersphere that is the image of the axial current [Formula: see text] in Euclidean space under this mapping.
Low-frequency response of a buried object in a lossy ground
Authors: Helaly A. , Shafai L. , Sebak A.
Published: April 2011

An approximate method is developed for treating problems of electromagnetic scattering, at low frequencies, from a buried object in a lossy ground and excited by a source located in the air region above. The field incident on the object's surface is calculated using the dyadic Green's functions for a half-space. Neglecting the coupling between the air–Earth interface and the object as a first-order approximation at low frequencies, we formulate the scattering problem in terms of the magnetic-field integral equation in conjunction with the impedance boundary conditions. The method of moments is then used to reduce the magnetic-field integral equation to a matrix one in order to determine the induced surface currents. The total scattered field is separated into two terms. One is the direct scattered field, which acts as if no buried inhomogeneity were present. The other term is the anomalous field, which represents the presence of the inhomogeneity. Solutions have been generated, and the numerical results are examined for a few limiting cases to confirm their accuracy. The formulation is then applied for investigating scattering by buried steel spheres. The numerical results show that the method can be used for detecting buried objects.
Effect of modulation on the onset of thermal convection in a viscoelastic fluid-saturated sparsely packed porous layer
Authors: Rudraiah N. , Radhadevi P. V. , Kaloni P. N.
Published: April 2011

The stability of a Boussinesq viscoelastic fluid-saturated horizontal porous layer, when the boundaries of the layer are subjected to periodic temperature modulation, is analyzed. The Darcy–Forchheimer–Brinkman–Oldroyd model is employed and only infinitesimal disturbances are considered. Three cases of the oscillating temperature field were examined: (a) symmetric, so that the wall temperatures are modulated in phase, (b) asymmetric, corresponding to out-of-phase modulation, and (c) only the bottom wall is modulated. Perturbation solution in powers of the amplitude of the applied field is obtained. The effect of the frequency of modulation on the stability is clearly shown. Possibilities of the occurrence of subcritical instabilities are also discussed. It is shown that an increase in the elastic parameters A1 and A2 has a stabilizing influence. An increase in the Prandtl number destabilizes the system for small values of the frequency but stabilizes the systems for large values of the frequency. It is shown that the system is most stable when the boundary temperatures are modulated out of phase. The maximum range of ε when subcritical instabilities exist is also determined.
Rotational line strengths in 3Σ+–3Σ− electronic transitions. The β3Σu+ – X3Σg− and A3Σu+ – X3Σg− systems of molecular oxygen
Authors: Lewis B. R. , Gibson S. T.
Published: April 2011

Rotational line strengths are given for 3Σ+(int) – 3Σ−(int) transitions arising from spin–orbit coupling. Observed branch intensities for the forbidden β3Σu+ – X3Σg− transition of O2 may be explained by assuming spin–orbit mixing of β3Σu+ with the B3Σu− and E3Σu− states. On the other hand, observed branch intensities for the Herzberg I A3Σu+ – X3Σg− transition of O2 may be explained only by assuming mixing with 3Σ and 3Π states. In neither case do earlier formulae, derived assuming a single 3Π perturber, apply.
On the photoproduction of gravitons on spinor particles
Authors: Long Hoang Ngoc , Huong Le Khac
Published: April 2011

The photoproduction of gravitons on spinor particles in the gravitational theory is considered. Contrary to the result of B. H. Mironovski (Zh. Eksp. Teor. Fiz. 48, 358 (1965)), we show that in the low-energy limit the photon intermediate states give the main contribution to the cross section. In both low- and high-energy limits the probability of graviton creation is largest in the direction of the photon motion.
Lower energy photon cross sections near atomic shell edges
Authors: Ghosh Manjusree , Ghose S. K. , Das S. C. , Bhattacharyya N. , Chowdhuri P. , Gupta S. K. Sen , Chaudhuri N.
Published: April 2011

Photon attenuation cross sections have been measured from time to time using radioactive isotopes as photon sources in various geometries. There are, however, inconsistencies between the measured values and the available tabulated values of attenuation coefficients based on different theoretical models. The measured values are particularly deficient for photon energies in the neighbourhood of the K-shell binding energies of attenuator elements. With the objective of filling such gaps in the experimental data as well as improving the data of earlier measurements, we have undertaken the present measurements in the energy region 43–1330 KeV. The measurements are made with the transmission technique using a NaI detector in the "good geometry," in which no gamma-ray photon scattered from the absorber at an angle greater than 0.3° can reach the detector. Results covering the elements from Z = 6–92 are presented and compared with the tabulated values of Hubbell et al. and Schaupp et al.
A laser-excited three-level atom
Authors: Mavroyannis Constantine
Published: April 2011

We considered the excitation spectra for the excited states of a three-level atom, where the strong and the weak atomic transitions are driven by resonant and nonresonant laser fields, respectively. The spectral functions describing the excitation spectra for the electric dipole allowed excited state and for the metastable state of the atom have been derived when both laser fields are quantized as well as when they are treated as classical entities. In the low-intensity limit of the laser field operating in the strong transition, there are two short-lifetime excitations, the spontaneous one and the induced one, which appear at the same frequency, and a long-lifetime excitation induced by the weak laser field. These excitations compete with each other at resonance as well as at finite detunings of the weak laser field. In the high-intensity limit of the laser field operating in the strong transition, the competition is between the short- and the long-lifetime side bands, which are induced by the strong and the weak laser fields, respectively. The ratio of the maximum intensities of the peaks describing the long- and the short-lifetime excitations exhibits a resonance variation with the detuning of the weak laser field. Comparison between the results obtained when the laser fields are treated as quantized and as classical entities is made.
Transition from discrete to continuous spectrum: separable potential in one dimension
Authors: Muga J. G. , Snider R. F.
Published: April 2011

An analysis is made of the transition from the discrete to the continuous spectrum for a separable potential in one dimension. The role played by the length of the box and the convergence parameter, ε, in the different limiting operations is discussed. Relations are found between scattering and perturbation theory matrices and wave functions in momentum representation. In particular, the known expression relating the level shift to the phase shift is recovered. The scattering and Brillouin–Wigner perturbation wave functions are in general not simply related by a phase factor.
On the infrared spectrum of solid hydrogen deuteride
Authors: McKellar A. R. W. , Clouter M. J.
Published: April 2011

The spectrum of solid hydrogen deuteride has been studied in the far-infrared (80–200 cm−1) and mid-infrared (3600–4500 cm−1) regions using a Fourier transform spectrometer and a moderately high spectral resolution of 0.09 cm−1. Spectra of the liquid were also recorded for comparison purposes. The pure rotational R0(0) transition at 88 cm−1 was found to have an integrated intensity of 1.78 ± 0.10 cm−2, in good agreement with a recent theoretical prediction. The shape of R0(0) appears to be best represented as the sum of two near-Lorentzian components. These may be related to the presence or absence of nearest neighbor H2 or D2 impurities in the crystal. The fundamental band in the mid-infrared is more complicated, and its detailed shape is not completely understood at this time. The profile of the band in the 3710 cm−1 region of the R1(0) transition is compared with a recent theoretical calculation. The presence of numerous sharp lines due to Q1(1) transitions in impurity H2 molecules around 4150 cm−1 is also noted.
Deriving the path integral from the operator formalism
Authors: Shiekh A. Y.
Published: April 2011

The path integral is derived from the operator formalism with a little more caution than usual.
SP(2)–BRST quantization of the antisymmetric tensor gauge theory
Authors: Chung Won-Sang , Chung Minho , Kim Jae-Kwan
Published: April 2011

A general method is given for the construction of gauge-fixed BRS and anti-BRS invariant action for the antisymmetric tensor gauge theory. The method is based on the single requirement that the space of fields carries an irreducible representation of the SP(2)–BRST algebra.
Nonlinear electrohydrodynamic Kelvin–Helmholtz instability conditions of an interface between two fluids under the effect of a normal periodic electric field
Authors: Shehawey E. F. El , Gawaad N. R. Abd El
Published: April 2011

The electrohydrodynamic Kelvin–Helmholtz instability conditions of an interface separating two dielectric streaming fluids, stressed by a normal electric field in absence of surface charges on the interface, are studied. We use the method of multiple scales to solve nonlinear equations. In the first-order problem we obtained Mathieu's differential equation. For the second-order problem, we obtain the nonhomogeneous Mathieu equation and we use the method of multiple scales to obtain a sequence of equations. In the third-order problem, we obtain the second-order differential equation of periodic coefficients; we also obtain a formula for surface elevation, and we determine the instability conditions.
A theory of gravity with broken symmetry
Authors: Accioly A. J. , Pimentel B. M.
Published: April 2011

The consequences of introducing a symmetry-breaking mechanism in the gravitational theory of Callan et al. (Ann. Phys. (N.Y.), 59, 42 (1970)) are investigated. It is shown, in particular, that although the chaotic inflationary scenario does not work in their original theory, it can be realized in the framework of the broken symmetric theory.
Formation of clusters on relativistic charged-particle multiplicity
Authors: Ahmad Tauseef , Irfan M. , Ahsan M. Z.
Published: April 2011

Cluster size and its dependence on the multiplicity of relativistic charged particles for pion–nucleus interactions at 340 GeV/c in nuclear emulsions are presented and compared with pion–nucleon interactions at the same energy. The maximum number of charged particles constituting a cluster has been observed to be four for events having higher multiplicity, i.e., Ns > 9, while this number turns out to be three for disintegrations with Ns ≤ 9. Finally, it may be concluded that the mechanisms of hadron–nucleus and hadron–nucleon interactions are almost identical.
Global color SU(3) is not a spontaneously broken symmetry in quantum chromodynamics
Authors: Li Fu-Bin
Published: April 2011

We find that the global color SU(3) is not a spontaneously broken symmetry in quantum chromodynamics from analysis of the Dyson–Schwinger equation. From this we conclude that the global color symmetry remains exact.
Operator regularization in Chern–Simons theory
Authors: McKeon D. G. C.
Published: April 2011

We demonstrate how operator regularization can be employed in three-dimensional Chern–Simons field theories. An explicit calculation of the vacuum polarization to one-loop order using this technique gives a nonlocal, transverse result that suggest a radiatively induced kinetic term for the vector field. Similarly, the spinor self-energy is finite and nonlocal when it interacts with a Chern–Simons field.
The successive perturbation method in the various orders of perturbation
Authors: Popescu V. A. , Popescu I. M. , Jitaru M.
Published: April 2011

We consider the case where the radius of convergence of the perturbation expansion can be related to a "crossing" of two energy levels in the complex plane of the interaction parameter. This case is suitable for the comparison of the performance of the successive perturbation method with those of the Padé, Borel–Padé, and the variational functional methods.
Développement complet de la polarisabilité des molécules tétraédriques XY4
Authors: Boutahar A. , Loete M.
Published: April 2011

A new model of polarizability is presented consistent with the Hamiltonian of tetrahedral molecules XY4. Using a coupling scheme in the Td group, polarizability operators are obtained up to any order of approximation for all vibration–rotation bands of any symmetry. This model leads to an unique formula for matrix elements of these operators. We also give the general expression for the Raman intensity of a transition.
Optical absorption in gold caused by a granular dielectric overlayer
Authors: Truong Vo-Van , Ashrit P. V. , Bader G. , Courteau P. , Girouard F. E. , Yamaguchi Tomuo
Published: April 2011

Light can be used to excite surface plasmons if there are proper mechanisms for coupling with those surface plasmons. This coupling can usually be achieved via surface roughness or evanescent waves in attenuated total-reflection experiments. In the present work, we report evidence of the possibility of having a resonant optical absorption when a granular dielectric layer is deposited on a metallic surface. Very thin films of MgF2 of mass thickness up to 8 nm have been used as a discontinuous overcoat on Au films of 100 nm thickness. Reflectivity measurements with p-polarized light incident at 40° show a resonant-type absorption near 520 nm when the dielectric layer is added to the Au surface. As the MgF2 film grows thicker and becomes continuous this absorption feature is no longer prominent. To account for this phenomenon, an effective-medium theory is used to describe the optical behavior of the coated Au surface. By including mirror-image effects in the dipole approximation, basic features of experimental measurements can be reproduced.
Neutron diffraction study of the structure of the antifluorite crystal (NH4)2TeCl6
Authors: Armstrong Robin L. , Dufort Paul , Powell Brian M.
Published: April 2011

A neutron diffraction study of the crystal structure of (NH4)2TeCl6 is presented. The data support a previous contention that this crystal undergoes a ferrorotative structural phase transition at 85 K, from a cubic structure with space group Oh5 to a trigonal structure with space group C3i2. The primary-order parameter is the rotation angle, Φ, of the TeCl6 octahedra about a [111] axis of the cubic phase. The data indicate that the temperature dependence of Φ is non-mean-field like over an extended reduced temperature range.
Generalized characters of the level-one Wess–Zumino–Witten model for simply laced groups on Riemann surfaces
Authors: Choi Jae Hoon , Kim Jae Kwan
Published: April 2011

The generalized characters of the level-one Al, Dl, and El Wess–Zumino–Witten models on the higher genus Riemann surfaces are obtained from their behaviors under the pinching limit of the zero-homology cycles. It is important in the construction of the higher genus characters that these models have fusion rules of the same type as the rational Gaussian model. The two-point correlators are also obtained by pinching the nonzero-homology cycle.
Positron annihilation in InPb alloy single crystals
Authors: Parker K. T. , Stewart A. T.
Published: April 2011

Electron momenta in Pb and PbIn alloys were measured by the positron annihilation technique. The distributions of momentum observed in single crystals of the specimens showed appreciable anisotropy. A model of the known Fermi surface of Pb near the (111) zone face was adjusted to fit the data. A similar model for the alloys was used to determine kF as a function of In concentration in the range 0 < In < 48 at.%. The results are remarkably like free electron theory.
Nucleon and isobar properties in a relativistic Hartree–Fock calculation with vector Richardson potential and various radial forms for scalar mass terms
Authors: Dey J. , Dey M. , Mukhopadhaya G. , Samanta B.C.
Published: April 2011

Mean-field models of the nucleon (N) and the delta (Δ) are established with the two-quark vector Richardson potential along with various prescriptions for a running quark mass (single particle) in the Dirac–Hartree–Fock formalism. The N–Δ splitting is obtained from colour magnetic interaction and the results for gA and the magnetic moment are discussed. An effective density dependent one-body potential U(ρ) for quarks at a given density ρ inside the nucleon is derived. Asymptotic freedom and confinement properties are built-in in U(ρ) and the model dependence is restricted to the intermediate densities.
Finite-size scaling of O(n) models with singular behaviour: Magnetization and susceptibility in the presence of an external field
Authors: Allen Scott , Pathria R. K.
Published: April 2011

The analysis of a previous study (Allen and Pathria. Can. J. Phys. 67, 952 (1989)) on finite-size effects in systems with O(n) symmetry [Formula: see text], confined to geometry Ld−d′ × ∞d′ (where d and d′ are continuous variables such that 2 < d′ < d < 4) and subjected to periodic boundary conditions, is extended (i) to include the region of first-order phase transition (T < Tc) as well as the region of second-order phase transition [Formula: see text] and (ii) to allow the presence of an external field H > 0. Predictions, involving both amplitudes and exponents, are made on the magnetization m and susceptibility χ in different regimes of the variables T, H, and L. Analytical verification of the predicted results is carried out in the case of the spherical model of ferromagnetism (n = ∞), and complete agreement is found.
Renormalization of the energies stored around a Wiener–Hopf structure: I
Authors: Mitsioulis George
Published: April 2011

A programme of renormalization of the electromagnetic energy stored around a structure admitting a solution through the Wiener–Hopf technique is proposed. The infinites of the stored magnetic energy also appear in the stored electric energy and they are suppressed freely. There are divergencies due to spatial integrations that prove to be completely renormalizable. Moreover the Wiener–Hopf procedure for the solution of the radiation from the semi-infinite parallel-plate duct gives rise to two other kinds of divergencies. First, the form of the spectrum eigenfunction causes a contribution to the stored energies from the wave-number visible region where the eigenfunction is "peaked" at certain points. Second, the squared spectrum eigenfunctions have a nonsummable singularity at the lower boundary of the visible region. The renormalizability of the formulae of the energies in both of these cases is proved.
Transverse magnetic scattering by parallel conducting elliptic cylinders
Authors: Sebak A.
Published: April 2011

A boundary value solution to the problem of transverse magnetic multiple scattering by M parallel perfectly conducting elliptic cylinders is presented. The solution is an exact one and based on the separation-of-variables technique and the addition theorem for Mathieu functions. It is expressed in terms of a system of simultaneous linear equations of infinite order, which is then truncated for numerical computations. Representative numerical results for the scattered field by two cylinders are then generated, for some selected sizes and orientations parameters, and presented.
Transient currents on a cylinder excited by a parallel line-current
Authors: Ciric I. R. , Ma J.
Published: April 2011

An analytical treatment of the currents induced on a perfectly conducting circular cylinder by a cylindrical electromagnetic wave, generated by a parallel filament carrying a unit-step current, is presented. An expression is derived for the induced current density, which is theoretically valid for both the illuminated and shadow regions, and for all time ranges. It consists of three parts: a series of natural resonance modes, a series of integral terms, and a constant term that corresponds to the steady-state induced current. It is found that the series are rapidly convergent for all time ranges in the shadow region, and for late times and also for intermediate times at larger angles in the illuminated region, only the first few terms in these series being sufficient to give accurate numerical results.
Solar-neutrino neutral-current detection methods in the Sudbury neutrino observatory
Authors: Hargrove C. K. , Paterson D. J.
Published: April 2011

The Sudbury Neutrino Observatory will study the solar-neutrino problem through the detection of charged-current (CC), neutral-current (NC), and elastic-scattering (ES) interactions of solar neutrinos with heavy water. The measurement of the NC rate relative to the CC rate provides a nearly model-independent method of observing neutrino oscillations. The NC interaction breaks up the deuteron producing a neutron and a proton. The interaction rate in the original design is measured by observing Čerenkov light from showers produced by neutron-capture γ rays from the capture of the NC neutrons by a selected additive to the heavy water. These signals overlap the CC and ES signals, so that the measurement of the NC rate requires the subtraction of two signals obtained at different times. This paper describes our investigation of an alternate detection method in which the thermalized neutrons are captured by (n, α) or (n, p) reactions on light nuclei. The resulting charged-particle products are uniquely detected by scintillators or proportional counters, completely separating this NC signal from the CC and ES Čerenkov signals, thus simplifying its measurement, improving its significance, and allowing observation of otherwise unobservable short-term NC fluctuations. Although background rates for the new techniques have not yet been determined, the experimental advantages justify further development work.
An application of the interfacial wave theory of solidification
Authors: Andonowati Andonowati
Published: April 2011

In this paper we apply the interfacial wave theory of dendritic crystal growth to the case in which the thermal diffusivity constant and the specific heat of the liquid state are different from those of the solid state. The problem is formulated as a linear eigenvalue problem. A quantum condition for the eigenvalues is derived and a discrete set of possible solutions is found. The selection problem is solved using the global neutral stable state analysis proposed by the interfacial wave theory.
Ansatz and consistency
Authors: Kao W. F.
Published: April 2011

We study the consistency conditions and the implications that come along with an operational defintion of an Ansatz. These consistency checks are applied to justify skyrmion and monopole Ansätze. The Friedman–Robertson–Walker metric is discussed. We also comment on Coleman's conjecture and the importance of the spherically symmetric Ansatz.
Analysis of gas amplification in Kr-mixture-filled proportional counters by double parametrization method
Authors: Akande Wole
Published: April 2011

Gas amplification in Kr, Kr-hydrocarbon, and Kr-CO2 filled proportional counters are estimated using a double parametrization analytic technique. Townsend first-ionization coefficient data were generated for the mixtures from the experimental values of their constituents. The fit of an expression to the data enabled important parameters characterizing each mixture to be determined. These were then used to evaluate the integral in the gas-gain equation. The resulting data were again fitted with another analytic formula, to obtain constants that afford easy evaluation of the gas gain in the mixtures. The results obtained were compared with available experimental data. Physical factors that may be responsible for differences between experimental and calculated gas gain are also discussed.
A three-dimensional gauge theory
Authors: McKeon D. G. C.
Published: April 2011

We investigate a three-dimensional gauge theory modeled on Chern–Simons theory. The Lagrangian is most compactly written in terms of a two-index tensor that can be decomposed into fields with spins zero, one, and two. These all mix under the gauge transformation. The background-field method of quantization is used in conjunction with operator regularization to compute the real part of the two-point function for the scalar field.
Evaluation of integrals using general partial-fraction expansions
Authors: Davies K. T. R. , Wu J. S. , Davies R. W.
Published: April 2011

The function [(x – t1)″1 (x – t2)″2 … (x – tN)″N]−1 with N, [Formula: see text], is explicitly expanded in partial fractions. A general recursion relation is also derived. Of particular interest are the cases N = 2 and N = 3. For N = 2, three partial-fraction expansions are compared and a "symmetrical" expansion is shown to be the most useful for evaluating various finite-limit and infinite-limit principal-value integrals. Such expressions are prototypes of integrals containing products of Green's functions, which are presently being studied in intermediate-energy nuclear physics. Also, a complex-contour evaluation provides another derivation of the symmetrical partial-fraction expansions.
Some aspects of hadrons produced in nuclear emulsion at high energies
Authors: Khushnood H. , Ansari A. R. , Irfan M.
Published: April 2011

Angular characteristics of charged shower particles produced in 50 GeV π−–emulsion and 400 GeV p–emulsion collisions are investigated in terms of pseudorapidity, η. The analysis of the data reveals that about 90% of the events at 400 GeV have at least one cluster, where as at 50 GeV the number of events having at least one single cluster lies between 60–70%. Furthermore, from the information obtained by studying short–short and short–long correlations, it may be concluded that there might be several clusters present in a disintegration caused by 50 and 400 GeV hadrons in a nuclear emulsion and each cluster should decay into a minimum of three charged particles. Finally, the dependence of the angular characteristics of charged shower particles on the size of the target at both 50 and 400 GeV is also investigated.
A review of the October 21, 1989 red aurora seen in Japan and from the AKEBONO (EXOS-D) satellite
Authors: Oguti T.
Published: April 2011

Observations of the October 21, 1989 red aurora from the ground and AKEBONO satellite are reviewed mainly on the topics presented at the workshop on the aurora, held in Solar Terrestrial Environment Laboratory on January 17–18, 1991. Electric-field fluctuations associated with the auroral oval during the observation, together with auroral green-rayed structures embedded in the red veil strongly suggest that some electron acceleration mechanism was operative in the particle precipitation. Therefore this was not a typical stable auroral red (SAR) arc. This red aurora was most likely located at a low-latitude portion of an expansion aurora during an auroral substorm. The geomagnetic conditions at the time of the aurora were quite similar to those during the occurrence of a SAR arc. It occurred during a susbtorm that broke out at the maximum Dst (disturbance with storm time) phase of a magnetic storm, with an auroral expansion initiated from low latitude on a well-expanded auroral oval. The difference in conditions between a typical SAR arc and this red aurora with green-ray structures is to be studied further.
Threshold pion photoproduction in the Skyrme model
Authors: Zhang Jingbo , Mobed Nader
Published: April 2011

Threshold photoproduction of pions on the nucleon is studied in the Skyrme model. Both the rotational and translational degrees of freedom of the Skyrmion are included in the calculations. It is found that in the case of neutral pion production there is a sizeable cancellation between the nucleon pole term and the anomalous contact term. This cancellation is a unique feature of the model and provides an important test of the validity of the model. A definitive conclusion must await a resolution of the existing controversies about the experimental data.
Elastic anomalies of Hg2X2 compounds
Authors: Viswanathan K. S. , Ramani J. C. Jeeja
Published: April 2011

The anomalies of the second-, third-, and fourth-order elastic constants are considered for the phase transition of Hg2X2 type of compounds. Expressions are obtained for the equilibrium values of the order parameters in the ferroelastic phase from the stability conditions. The fluctuation in the order parameter is evaluated from the Landau–Khalatnikov equation. An expression is derived for the shift in the zero-point energy in the low-temperature ferroelastic phase and the specific heat anomaly. It is shown that these are proportional to (T − T)2 and (T − Tc), respectively. All the anomalies of the second-order elastic (SOE) constants are obtained from a single general formula, and relations among them are established. The temperature variation of the SOE constants in the limit [Formula: see text] is discussed. Similarly, expressions are derived for the anomalies of the third- and fourth-order elastic constants. In the limit [Formula: see text] it is shown that these constants diverge as [Formula: see text] and [Formula: see text], respectively.
Generalization of a perfect fluid solution in nonsymmetric gravitation theory
Authors: Vlachynsky E. J.
Published: April 2011

A plane symmetric cosmological solution with perfect fluid has been derived in the context of the complex nonsymmetric gravitation theory by Kunstatter, Moffat, and Savaria. Their solution can be converted into a solution of the hypercomplex nonsymmetric gravitation theory (NGT) by a redefinition (κ → iκ) of the parameter (κ) appearing in the antisymmetric part of the fundamental tensor g[μν]. We generalize the NGT solution by assuming a more general Ansatz for the antisymmetric part of g[μν].
Anharmonic oscillator analysis using modified Airy functions
Authors: Goyal I. C. , Roy Sukhdev , Ghatak A. K. , Gallawa R. L.
Published: April 2011

We have applied the modified Airy function (MAF) method to the analysis of an anharmonic oscillator, characterized by the potential V(x) = k x2/2 + a x4, k > 0, a > 0. The MAF method gives an accurate closed-form expression for the wave function as well as very accurate eigenvalues with much less numerical effort than the five-term (eighth-order) WKBJ approximation. The application of the first-order perturbation correction to the MAF eigenvalues makes them even more accurate than those obtained by the five-term WKBJ approximation.
57Fe Mössbauer isomer shifts in random face-centered cubic Fe–Ni alloys: Experiment versus electronic structure calculations
Authors: Rancourt D. G. , Ping J. Y. , Dang M.-Z.
Published: April 2011

Measured 57Fe-isomer shifts for face-centered cubic FeyNi1−y alloys show a linear variation with ∂1S/∂y = +0.10 mm s−1 up to [Formula: see text] followed by a plateau at [Formula: see text], up to the structural stability limit at [Formula: see text]. This is in disagreement with recent ab initio calculations, however, the increase at [Formula: see text] is in quantitative agreement with an older modified tight-binding approach in which the increase arises from an atomic volume dependence. The plateau is an anomaly that sets in at the same composition as that at which the saturation moments start to deviate from the Slater–Pauling curve.
Dipole oscillator strengths for the alkalilike ions
Authors: Liaw S. S.
Published: April 2011

We calculate the oscillator strengths of some transitions for the alkalilike ions in the Dirac–Fock approximation. The oscillator strengths calculated have included a nonlocal term derived previously by Feldman and Fulton from quantum electrodynamics. The numerical values of the length and velocity forms are shown to be equal. Most results of the present calculation are in good agreement with the available experimental data. Thus the formalism, with no parameters to be adjusted in contrast to the semiempirical methods, offers a simple and effective way to obtain qualitatively satisfactory oscillator strengths for large alkalilike ions.
Composition et coefficients de transport des plasmas de matériaux plastiques (polymères)
Authors: Abbaoui M. , Koalaga Z. , Lefort A.
Published: April 2011

Composition at equilibrium, electrical and thermal conductivities, and dynamic viscosity coefficient are calculated for plasmas produced by vaporization of plastic materials (polymers) containing some percentage of carbon, hydrogen, oxygen, and nitrogen. Temperature and pressure ranges are 5000 – 30 000 K and 0.1–1 MPA. By indicating the role played by some particles on the characteristics of the discharge, this study has shown the influence of the nature of the material.[Journal translation]
A symmetric figure-of-eight optical fiber resonator
Authors: Zhang Jian-Luo , Lit John W. Y.
Published: April 2011

A theoretical study is presented of a figure-of-eight optical fiber resonator that has two single-mode couplers. The output intensities of the optical fiber resonator are investigated in terms of the coupling coefficients and losses. The finesse and contrast are discussed. Compared with a transversely coupled fiber Fabry–Perot resonator, this resonator has an all-fiber configuration, and is more easily realized. Compared with a direct-coupling fiber ring resonator, it offers reflected outputs that may be useful in some applications.