bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of the parity violation in the quasi-elastic scattering of polarized electrons from 9Be
Authors: Neuhausen Reiner
Published: April 2011

The standard theory of electroweak interactions predicts a parity nonconserving asymmetry in the order of 1 × 10−5 for the quasi-elastic scattering of 300 MeV longitudinally polarized electrons from nuclei at backward angles. The experimental setup for the detection of such small effects is described, and the procedure of data taking and analysis is discussed with regard to systematic uncertainties. The experimental asymmetry is found to be Aexp = (−3.51 ± 0.68 ± 0.20) × 10−6, where the first quoted error specifies the statistical uncertainty, the second one, the systematical. Aexp is interpreted in terms of model-independent coupling constants between the weak neutral current and the nucleon.
ΔS = 0 weak interactions at the quark level
Authors: McKellar Bruce H. J.
Published: April 2011

The calculation of short-distance gluon exchange corrections to the ΔS = 0 weak interaction at the quark level is described. Results are given for the coefficients of the 36 independent four-quark operators involving u, d, and s quarks explicitly, and for the 16 independent operators, which remain when s quarks are eliminated and only u and d quarks explicitly occur in the operators.
Reduction of the effects of transverse polarization in a measurement of parity violation in proton–proton scattering at 230 MeV
Authors: Birchall J.
Published: April 2011

An overview is given of some of the sources of systematic error expected in a new measurement of parity violation in proton–roton scattering at 230 MeV. The experiment involves the measurement of an angular distribution of the longitudinal analyzing power, Az(θ), as well as of the more conventionally measured total analyzing power, Az.
Studies of parity violation using polarized slow neutron beams
Authors: Alberi J. , Hart R. , Jeenicke E. , Ost R. , Wilson Richard , Shroder I. G. , Avenier A. , Bagieu G. , Benkoula H. , Cavaignac J. F. , Idrissi A. , Koang D. H. , Vignon B.
Published: April 2011

In this paper we review the work that has been done on studies of parity violation in nucleon systems using polarized beams of slow neutrons, first describing an early attempt by Haas et al. (Phys. Rev. 116, 1211 (1959)) and ending with some suggestions and predictions for the future.
A summary of theoretical discussion
Authors: Henley E. M.
Published: April 2011

Some of the points made in the presentations are reviewed, and questions are raised with respect to the theory of hadronic parity violation.
Analysis of an arbitrarily excited – loaded dipole antenna with a derived expression for the field in the feed gap
Authors: Saoudy S. A. , Hamid M.
Published: April 2011

Expressions are derived for the aperture time-harmonic electromagnetic fields in the feed gap of a solid infinite antenna along the z axis. This is done by matching the Fourier representation of the external electromagnetic fields to the Fourier representation of the fields inside the feed gap. The Fourier expansion is built up by superposition of basic sets of [Formula: see text]-independent cylindrical waves that are obtained from the solution of Helmholtz equations governing z-directed electric Hertzian potentials. The z-directed electric field, which is in the form of a Fourier–Bessel series, is then used to calculate the input admittance of an infinitely long antenna excited across a practically wide feed gap. This is done using the axial field discontinuity method, which is based on the Wiener–Hopf type analysis. The method treats the dipole antenna as a series combination of longitudinal electric-field surface functions that may exist owing to feeding and (or) loading. A comparison is made between the radiation characteristics based on the Fourier-series field inside a wide gap and those obtained using the delta-function excitation for a finite-length dipole antenna with various excitation and loading conditions.
Isotope shifts in the Cl2B–X system
Authors: Gouédard G. , Billy N. , Girard B. , Vigué J.
Published: April 2011

We have studied the fluorescence excitation spectrum of natural Cl2 molecules induced by a monomode ring dye laser around various X(ν″ = 0) → B(ν′ ≥ 18) bandheads. Contrary to the main 35–35Cl2 isotope, the less abundant species 35–37Cl2 and 37–37Cl2 have not, up to now, been thoroughly investigated in this region. Our experiment has allowed a precise determination of a number of isotope shifts, which are shown to be calculable by a local interpolation procedure of Coxon's data, using the concept of mass-reduced quantum numbers.
Étude générale des déplacements à la réflexion totale sur l'interface séparant deux milieux relativement mobiles dans le plan d'incidence
Authors: Kallas Noël C.
Published: April 2011

We consider the case, never treated so far, of total internal reflection on the boundary between two media in relative motion in the incidence plane, which involves the Goos–Hänchen longitudinal shift Lx and the Imbert transverse shift Ly. We show how these effects, already occurring without relative motion, are modified by the motion of the two media. The particular case of two identical media is investigated; we show that new possibilities of total internal reflection appear even at small velocities.
Production of metastable and resonant atoms in rare-gas (He, Ne, Ar) radio-frequency and microwave-sustained discharges
Authors: Ricard A. , Barbeau C. , Besner A. , Hubert J. , Margot-Chaker J. , Moisan M. , Sauvé G.
Published: April 2011

Radial density distributions of excited atoms in plasma columns of helium, neon, and argon, sustained by a travelling electromagnetic surface wave, are examined as a function of frequency over the range 200 kHz – 2450 MHz. This investigation is conducted using an end-on measurement method. At low frequencies (<50 MHz), these radial distributions show a maximum at the axis (J0 Bessel-like behavior), whereas as frequency is increased beyond 50 MHz up to 2450 MHz, the radial distributions flatten and finally exhibit a minimum at the axis with a maximum close to the tube wall. Comparison with a DC positive column plasma, working under the same gas-pressure and tube-diameter conditions, is made as a function of cross-section average electron density. The surface-wave discharge operated in the microwave frequency range (>300 MHz) yields larger cross-section average densities for atoms in a metastable or resonant state, typically a factor of 2–3 at 1011 electrons∙cm−3. This result arises because the two types of discharges have different radial-density distributions for excited atoms.
Decay properties of a baryon
Authors: Bhattacharya Aparajita , Banerjee S. N.
Published: April 2011

The decay properties of the charmed baryon and proton have been computed in the context of the statistical model and are found to be in agreement with the corresponding experimental findings.
Two-body Dirac equation: illustration in one space dimension
Authors: Coutinho F. A. B. , Glöckle W. , Nogami Y. , Toyama F. M.
Published: April 2011

Various features that are characteristic of the two-body Dirac equation but not of the one-body Dirac equation are illustrated by means of solvable examples (mainly square-well potentials) in one space dimension. For the Lorentz character of the potential there are three types; vector, scalar, and pseudoscalar. We classify the bound-state solutions as normal and abnormal. As the interaction is adiabatically switched off, the energy of the normal solutions reaches 2m (the sum of the masses of the constituent particles), whereas the energy of the abnormal solutions becomes zero. When the sharp edge of the square-well potential is smeared out, some of the solutions become unnormalizable and hence unacceptable. This leads to a certain restriction on the choice of the potential. The two-body Dirac equation with a finite-range interaction is not exactly covariant. The degree of noncovariance is examined.
28Si + 28Si elastic scattering at energies above the Coulomb barrier
Authors: Kumar Ashok , Srivastava B. B.
Published: April 2011

A relatively simple procedure has been used to calculate the differential cross sections for 28Si + 28Si elastic scattering at Elab = 67, 74, 77, and 120 MeV. The nuclear interactions have been calculated microscopically using the equivalence relation between the matrix elements of the generator coordinate and the resonating group methods from the two-nucleon potential, which explains the two-nucleon data fairly well. The absorption effects due to the opening of the nonelastic channels are taken into account approximately by the classical sharp cutoff of partial waves. The calculated results are in quite good agreement with the available experimental data at most of these energies.
All-optical silicon-based integrated fiber-optic modulator, logic gate, and self-limiter
Authors: Normandin R. , Houghton D. C. , Simard-Normandin M. , Zhang Y.
Published: April 2011

We describe an all-optical mode cutoff modulator for use in fiber optics systems working at wavelengths in the 1.3–1.6-μm range. The active waveguide is silicon grown by molecular beam epitaxy, and the channels are fabricated by conventional lithographic techniques and used with standard single-mode fibers. Subnanosecond initiation and recovery times are achieved with less than 150 pJ of control energy in a three-port geometry suitable for use as a logic gate. We also present preliminary results when the guided light is near the bandgap energy and demonstrate self-limiting for integrating Kerr-like self-defocussing nonlinearities. In both cases, the operation of the device is largely wavelength independent and stable.
Design of polarization-encoded optical shadow-casting logic units using truth-table partitioning
Authors: Awwal Abdul Ahad S. , Karim Mohammad A.
Published: April 2011

The input pixel size of a polarization-encoded optical shadow-casting logic system is reduced by means of truth-table partitioning. The proposed design algorithm is used to encode the inputs of a three-input, two-output binary full adder. A comparison with alternative designs proves that the technique leads to an improved memory-efficient optical computing unit.
The three-dimensional point spread function and statistical image surface of the image-intensifier electron-optical system
Authors: Woźnicki J. M.
Published: April 2011

An improvement in the methods of numerical calculations of the field distribution and electron-optical ray tracing makes numerical evaluation of image-intensifier systems very practical for real devices. The essential means of assessing the system's properties are the classical two-dimensional point spread function (PSF) and the electron focal surface. However, the positions of separate image points depend on the initial photoelectron parameters, resulting in a statistical longitudinal spread of the image surface positions. This paper contains a three-dimensional PSF generalization based on a statistical-image-surface (SIS) concept, which is proposed for electron-optical systems. The aim of this work is to present a computer method for the numerical determination of the SIS concept and to show a sample application to the image-intensifier system with monochromatic illumination.
Passive mode locking with a nonlinear Michelson interferometer: transient and steady-state characteristics
Authors: Ouellette François , Piché Michel
Published: April 2011

The insertion of a nonlinear medium into one arm of a Michelson interferometer used as a mirror in a laser cavity is shown to produce intensity-dependent losses. The resulting nonlinearity yields passive mode locking since it favors the oscillation of an intense short pulse. The method is analyzed and compared with passive mode locking with a saturable absorber. The duration of the short pulse circulating in the laser cavity is shown to be ultimately limited by the linewidth of the gain curve. Experimental results obtained with a transversely excited atmospheric – CO2 laser illustrate some aspects of the dynamic behaviour of a laser equipped with such a device.
Guiding properties of multilayer dielectric planar waveguides
Authors: Lit John W. Y. , Li Yi-Fan , Hewak Daniel W.
Published: April 2011

Eigenvalue equations for guided modes in multilayer waveguides are given, along with equations for the field distributions. Closed analytic expressions are given to calculate the mode number of the guides. Two new concepts—fictitious half-phase shift and effective guide thickness—are extremely useful in the analysis of the field and in calculating the power carried by the different layers. General formulas for the dispersions caused by changes in various physical parameters are given. The study ends with illustrations using three-layer, four-layer, W-structure, and symmetrical seven-layer waveguides, as well as symmetrical periodic multilayer waveguides.
A rocket measurement of the O2 Infrared Atmospheric (0–0) band emission in the dayglow and a determination of the mesospheric ozone and atomic oxygen densities
Authors: Evans W. F. J. , McDade I. C. , Yuen J. , Llewellyn E. J.
Published: April 2011

Rocket measurements of the [Formula: see text] IR Atmospheric (0–0) band emission in the sunlit mesosphere, which were coordinated with an overpass of the Solar Mesospheric Explorer (SME) satellite, are reported. The IR Atmospheric band volume emission rates, derived from the data obtained with a matching pair of 1.27 μm radiometers, are presented and compared with the emission rates inferred from limb-scan observations made with the near-infrared spectrometer on the SME satellite. The rocket measurements are used to derive the ozone and atomic oxygen number densities in the sunlit mesosphere. The derived concentrations are compared with those obtained from other observations and model calculations.
Variational solution of bound states in a charged interacting scalar-field theory
Authors: Darewych J. W. , Polozov A. D.
Published: April 2011

Two interacting [Formula: see text] scalar fields in N spatial dimensions are investigated using the Gaussian variational approximation. The interaction is taken to be in the form [Formula: see text]. Two-particle bound-state solutions are obtained in the domain g < 2λ for N = 1 and 2. The nonrelativistic limit, which is also the weak-coupling limit, is shown to correspond to an attractive delta-function interaction. For N = 3, the Gaussian ansatz suggests triviality of the theory, in that the renormalized coupling constant is identically zero.
Berry phase for the SU(1,1) coherent state
Authors: Hong-Yi Fan , Zaidi H. R.
Published: April 2011

We derive a general expression for the Berry phase for the case of the SU(1,1) coherent state. The results are also applicable to one- and two-mode squeezed states.
Small-angle scattering of photons at low energies
Authors: Bhattacharyya Nanak , Ghose S. K. , Choudhuri N.
Published: April 2011

The results of a new set of photon–atom scattering measurements in a low momentum-transfer region (0.02–0.04 mc) for medium- and high-Z elemental scatterers in the form of foils are presented. A comparison with the theoretical results based on the Thomas–Fermi model for the incoherent scattering components and the numerical S-matrix predictions for the coherent Rayleigh-scattering amplitudes are also given. The present series of measurements fills a gap in the region of low momentum transfer that has not been covered by other recent scattering experiments.
On the stability of steady convective motion generated by internal heat sources in a magnetic field
Authors: Kolyshkin A. A.
Published: April 2011

The stability of steady convective motion of a viscous incompressible fluid in a transverse magnetic field is investigated using the method of small perturbations. The motion is caused by internal heat sources uniformly distributed within the vertical layer of the fluid. The stability analysis shows that the critical Grasshof number increases with the growth of the magnetic field. The role of the Prandtl and Hartmann numbers on the stability characteristics are discussed. For high Prandtl numbers, instability occurs in the form of thermal running waves.
The 1/Nc corrections to static properties of nucleons in the Skyrme model
Authors: He Han-Xin , Mobed Nader , Khanna Faqir C.
Published: April 2011

Corrections of O(1/Nc) to static properties of nucleons in the Skyrme model are calculated. The O(1/Nc) corrections due to quantization of collective coordinates are less than 4% for the axial charge and magnetic moment of the nucleon.
Zero-energy modes and Lüders' theorem
Authors: Capri A. Z. , Ferrari R.
Published: April 2011

We show for an explicitly solvable model in 1 + 1 dimensions that there are several possibilities that arise in connection with Lüders' theorem if zero-energy modes are present.
Probabilistic-topological theory of systems with discrete interactions: I. System representation by a hypergraph
Authors: Klonowski Wlodzimierz
Published: April 2011

The theory presented is applicable to any system with discrete interactions, i.e., one that lacks long-range crystal-like translational symmetry but is such that any of its structural elements interacts directly with only a finite (in most cases small) number of other elements, i.e., for materials such as cross-linked polymers, superpolymers (ferrofluids, wormlike micelles, colloidal necklaces), ceramics and glasses obtained by sol-gel processes, as well as for biophysical systems such as membrane receptors, cellular aggregates, neuronal branching patterns.The theory systematizes the information one needs to represent the system by a hypergraph, which then makes possible application of the so-called difference a posteriori (DAPOST) algorithm to calculate structural characteristics of the system and structure–property relationships. It is based on probabilistic and topological considerations; thus, it is applicable to systems far from thermodynamic equilibrium and to the analysis of spatiotemporal patterns.
Oscillator strengths in the Na sequence
Authors: Tiwary S. N. , Singh A. P. , Singh D. D. , Sharma R. J.
Published: April 2011

We have calculated the excitation energies and the length and velocity forms of the optical oscillator strengths for the resonance 1s22s22p63s2Se → 1s22s22p63p2P0 transition and the nonresonance 1s22s22p63s2Se → 1s22s22p64p2P0, 1s22s22p63p2P0 → 1s22s22p64s2Se and 1s22s22p64s2Se → 1s22s22p64p2P0 transitions in Na, Mg+, Al2+, Si3+, S5+, Ar7+, Ca9+, and Fe15+ systems. Inner-shell excitation in the P4+ ion has also been studied. The agreement between the length and velocity forms of the oscillator strengths is reasonably good.
Influence of uniaxial stress on hole effective masses in quantum wells
Authors: Lee Johnson , Vassell M. O.
Published: April 2011

The hole effective masses in quantum wells under uniaxial stress are investigated. The valence subband structures are determined from a 4 × 4 Luttinger–Kohn Hamiltonian together with a 4 × 4 strain Hamiltonian with appropriate boundary conditions. The variations of the hole effective masses with well width, stress, and potential-barrier height (or the corresponding alloy composition) are discussed and found to be drastic. For example, even if the quantum well is stress free, the variations of the hole effective masses with well width can range from +∞ to −∞ and are not constant, as predicted by the infinite potential-well model. The variations with stress indicate that the effective masses can become zero, depending on the direction and the magnitude of the stress.
Scattering of electromagnetic waves by arrays of ferrite cylindrical shells
Authors: El-Gamal M. Z. , Shafai L.
Published: April 2011

A method is developed that enables the solution of scattering by a finite number of cylindrical shells in a simple and accurate form. It is based on the analytical formulation using the boundary-value problem and a utilization of a point-matching technique. The method is then applied to study the effect of the shell-wall thickness as well as the effect of the applied dc magnetic field on the scattering properties of arrays of infinite anisotropic cylindrical shells. It is also used to determine the size and spacing of passive dielectric and magnetized ferrite reflectors to improve the directivity of antennas. In this latter case, a combination of the present method and a known space-perturbation technique is employed to optimize the antenna gain.
Exact interior solutions in higher dimensions
Authors: Krori K. D. , Borgohain P. , Das Kanika
Published: April 2011

We present in this paper some exact interior solutions in higher dimensional general relativity. The solutions are all physical and free from singularity.
Dynamical perturbation theory for the evaluation of the relaxation function
Authors: Kim I. M. , Ha Bae-Yeun
Published: April 2011

Use of the infinite continued-fraction representation has played an important role in the evaluation of the relaxation function of many-body systems. By using the method of recurrence relations, we propose here a dynamical perturbation theory for the evaluation of the infinite continued fraction. The analytic expression of the relaxation function is given in terms of the known relaxation function for the unperturbed system. Two illustrative examples are also given.
S-matrix pole trajectories for separable interactions
Authors: Roriz L. A. L. , Delfino A.
Published: April 2011

By solving the Lippmann–Schwinger equation in momentum space for a set of two-body separable interactions, we study eir S-matrix pole trajectories. The connection of such a study with the three-body bound-state collapse is also discussed.
Spin-polarized hydrogen, deuterium, and tritium: I. Ground-state energy calculated by a lowest order constrained-variation method
Authors: Haugen Magne , Østgaard Erlend
Published: April 2011

The ground-state energy of spin-polarized hydrogen, deuterium, and tritium is calculated by means of a modified variational lowest order constrained-variation method, and the calculations are done for five different two-body potentials. Spin-polarized H↓ is not self-bound according to our theoretical results for the ground-state binding energy. For spin-polarized D↓, however, we obtain theoretical results for the ground-state binding energy per particle from −0.42 K at an equilibrium particle density of 0.25 σ−3 or a molar volume of 121 cm3/mol to + 0.32 K at an equilibrium particle density of 0.21 σ−3 or a molar volume of 142 cm3/mol, where σ = 3.69 Å (1 Å = 10−10 m). It is, therefore, not clear whether spin-polarized deuterium should be self-bound or not. For spin-polarized T↓, we obtain theoretical results for the ground-state binding energy per particle from −4.73 K at an equilibrium particle density of 0.41 σ−3 or a molar volume of 74 cm3/mol to −1.21 K at an equilibrium particle density of 0.28 σ−3 or a molar volume of 109 cm3/mol.
The ultraviolet spectrum of a dayside aurora: 530–1500 Å
Authors: Gentieu E. P. , Eastes R. W. , Feldman P. D. , Christensen A. B.
Published: April 2011

Rocket-borne spectrometers have observed the high-latitude dayside aurora above Cape Parry, N.W.T. Ultraviolet spectra of optical emissions produced by ambient precipitating particles have been obtained in the wavelength region between 530 and 1500 Å, over a range of spectrometer line-of-sight orientations, from 100 km to the rocket apogee of 452 km. The spectrum below 1500 Å is dominated by transitions from neutral and singly ionized atomic oxygen. NI, NII, and molecular nitrogen emissions, which are prominent in day airglow and nighttime auroral spectra measured by the same instrumentation, are very weak, indicating energy from the dayside auroral particles is transferred to the atmosphere above most of the N2. Relative line strengths of OI and OII transitions in the high-latitude dayside aurora differ in comparison with either airglow or nighttime auroral observations. The differences arise from differing excitation mechanisms and radiative-transfer characteristics and indicate the far-UV region of the spectrum can serve as a useful probe for remotely sensing various auroral phenomena. Weak emission near 1170 Å is identified as the OI 3s′3D–2p42D intercombination transition at 1172 Å. Observed OI 1172 Å intensities are consistent with the branching-ratio measurements of Morrison
On the wave-particle-like solutions of nonlinear equations
Authors: Barut A. O. , Rusu P.
Published: April 2011

The problem of interpreting moving soliton solutions of some nonlinear equations as quantum-like particles is critically analyzed. Purely classical equations (sine-Gordon) as well as nonlinear quantum equations (Schrödinger, Dirac, Kelin–Gordon) are investigated. Three different definitions of energy associated with these equations are considered, and the functional relations replacing the de Broglie postulate, [Formula: see text], are explicitly given. Our analysis shows that fundamental problems generated by the nonlinear approach to quantum mechanics are still unsolved, and these theories have to be considered cautiously.
Matter tensor in scalar–tensorial theories of gravitation
Authors: Hafner Harry , Ionescu-Pallas Nicholas
Published: April 2011

Gravitational interaction is assumed to be partially geometrized and described by 10 potential functions in the framework of a Riemannian geometry. It is also partially nongeometrized and described by an additional scalar potential function nonlinearly coupled to the energy density. The scalar potential naturally leads to a conformally Riemannian metric, enabling us to completely geometrize the gravitation and to establish a close analogy with the Brans–Dicke theory. Finally, the scalar field is endowed with the rest mass, and we suggest that it be identified with the short-range graviscalar field.
Study of multiplicity and the pseudorapidity correlation in the forward and backward hemisphere for pions and protons emitted in a 12C – emulsion interaction at 4.5 A ∙ GeV/c
Authors: Ghosh Dipak , Roy Jaya , Sengupta Ranjan
Published: April 2011

The paper presents an in depth study of the forward and backward pseudorapidity correlations for pions and protons produced in a 12C – emulsion interaction at 4.5 A ∙ GeV/c. The angular distribution of protons and the pseudorapidity distribution of pions are pictured. The asymmetry parameter (A) and the forward – backward ratio (F/B) are shown as a function of the number of heavy particles (nh).
Indice hertzien d'une jonction polarisée
Authors: Blanc François , Fanguin René , Gillet Daniel , Gire Alain , Lomaglio Germaine , Raoult Gaston , Theobald Jean-Gérard
Published: April 2011

In previous papers, we have studied the variations of radiofrequency susceptibility of a junction versus dc polarization. Here, we study the effect of variations of the refraction index on a microwave. An increase of the carrier concentration produces a diminution of the index, a decrease of reflected power, and an increase of transmitted power. This is in agreement with the theory, which takes into account the local microwave field.
Squeezing caused by a change of mass in a harmonic oscillator
Authors: Hong-Yi Fan , Zaidi H. R.
Published: April 2011

It is shown that a mass change in a harmonic oscillator generates a squeezing transformation. Time-independent as well as time-dependent transformations are investigated. An expression for the interaction Hamiltonian responsible for squeezing and the equations of motion for the time evolution are derived.
A hole in the Arctic polar ozone layer during March 1986
Authors: Evans W. F. J.
Published: April 2011

A craterlike structure or "hole" in the Arctic polar ozone layer during March 1986 has been observed in the total ozone images from the total ozone mapping spectrometer instrument on the NIMBUS 7 satellite. Observations from ozonesondes in the vicinity of this crater show a depleted region in the altitude profile from 10 to 16 km. This altitude region of depleted ozone is similar to the depleted layer observed from 12 to 18 km within the Antarctic ozone hole. A comparison has been made between the ozone altitude profile outside the crater at Resolute, N.W.T., Canada (75°N), and the ozone altitude profile inside the crater at Lindenberg, German Democratic Republic, (55°N). The difference in these profiles demonstrates that the crater is due to a process that has altered the altitude distribution of ozone in the 10–16 km region. This depletion could be attributed to either a vertical circulation or a chemical-depletion process.
Simultaneous occurrence of ionization ledge and counterelectrojet in the equatorial ionosphere: observational evidence and its implications
Authors: Sharma P. , Raghavarao R.
Published: April 2011

In this paper we present observational evidence for the simultaneous occurrence of an ionization ledge in the topside and a counterelectrojet in the E-region altitudes of the equatorial ionosphere. The following morphological features of the ionization ledge are found to be the same as those of the counterelectrojet phenomenon: namely, occurrence on a sequence of days in succession, preferential occurrence during a solar minimum period as compared with a solar maximum period, occurrence in a limited longitudinal belt, and lunar control of the occurrence as revealed by our data.There is also a high degree of correlation on both magnetically quiet and magnetically disturbed days between the ionization ledge and the counterelectrojet. Our study brings out a close coupling in the occurrence and morphological features of the two low-latitude phenomena, even though they are widely separated in altitude. The implications of such a correlation, with special reference to the understanding of the dynamical coupling of the E and F regions in the equatorial ionosphere, are briefly discussed.We also report a hitherto unreported feature of the ionization anomaly, viz., its occurrence on certain days in a narrow (~30°) longitude belt. The observational evidence presented in this paper may lead to new insights into the understanding of the interrelationships between the three phenomena, the ionization ledge, the ionization anomaly, and the counterelectrojet, in the equatorial ionosphere.
Scattering by a radially inhomogeneous cylindrical dielectric shell due to an incident Gaussian beam
Authors: Rao T. C. K.
Published: April 2011

The problem of scattering by a radially inhomogeneous cylindrical dielectric shell due to an incident Gaussian beam is solved by a boundary-value procedure after first adapting a simplification proposed by Kozaki. The scattering coefficient is expressed as a product of the scattering coefficient due to an incident plane wave and a weighting function. Both transverse magnetic and transverse electric polarizations of the incident beam source are considered, and some representative numerical results of the scattered power pattern and the normalized backscattering cross section are presented for two specific inhomogeneous profiles. The variations of these quantities with the physical parameters of the dielectric shell are studied.
l/(q-1)-Expansion study of the q-color problem on a lattice
Authors: Bakaev A. V. , Ermilov A. N. , Kabanovich V. I. , Kurbatov A. M.
Published: April 2011

A series-expansion method is used to evaluate the number of configurations in the q-color problem.
Trajectories of material particles in Kerr–Newman–de Sitter space–time
Authors: Krori K. D. , Choudhury Ranjana , Sarmah J. C.
Published: April 2011

In this paper we show that in the Kerr–Newman–de Sitter space–time material particles may move in stable orbits in the equatorial plane (θ = π/2) of the Kerr–Newman black hole.
Distorted polar trajectories around a black hole in a gravitational field
Authors: Krori K. D. , Sarmah J. C.
Published: April 2011

In this paper we present how the polar trajectory ([Formula: see text] = constant plane) of particles moving around a black hole embedded in a gravitational field is distorted.
Far infrared absorption in gaseous CCl4 and CS2
Authors: Dagg I. R. , Missio M. , Anderson A. , Smith W. , Read L. A. A.
Published: April 2011

The absorption spectra of gaseous CS2, CCl4, and a gaseous mixture of CCl4 and argon at temperatures up to 400 K in the frequency region below 140 cm−1 are reported. From the results on CCl4, the octupole moment is estimated to be 16 ± 3.0 × 10−34 esu; the hexadecapole moment, 64 ± 12 × 10−42 esu. For CS2, if a previously measured value of 3.6 B for the quadrupole moment is assumed, the hexadecapole moment is estimated to be less that 24 × 10−42 esu, considerably less than an earlier theoretical estimate.
Distribution of particles in high-multiplicity exclusive hadron collisions
Authors: Hoeneisen Bruce
Published: April 2011

Extending a statistical model by Fermi, we obtain an approximate expression for the distribution of particles in high-multiplicity exclusive hadron collisions. Theory is compared with experiment for several exclusive reactions.
The 5s25p2 − (5s25p5d + 5s5p3 + 5s25p6s + 5s25p7s) transitions in Sb II and 5s25p − (5s5p2 + 5s2nl) transitions in Sb III
Authors: Arcimowicz B. , Joshi Y. N. , Kaufman V.
Published: April 2011

The spectrum of antimony was photographed in the 575–2300 Å region (1Å = 10−10 m) using a hollow cathode and a triggered spark source. The analysis of the 5s25p2 − (5s25p5d + 5s5p3 + 5s25p6s + 5s25p7s) transitions in Sb II spectrum was revised and interpreted on the basis of multiconfiguration interaction calculations. Accurate wavelength measurements of Sb III lines lead to a revised ground-state 5s25p2P interval value of 6574.5 cm−1.
Solitons in ion-beam plasmas bounded by cylindrical geometry
Authors: Das G. C. , Singh KH. Ibohanbi , Karmakar B.
Published: April 2011

Nonlinear ion-acoustic solitary waves are studied in a cylindrically bounded plasma consisting of ions and ion beams, along with multiple-temperature electrons, through the derivation of a Korteweg–deVries equation. The interaction of isothermality on the propagation of radially ingoing ion-acoustic waves in various plasmas exerts a drastic modifying effect on the existence and behaviour of the solitons. The results have been compared extensively with those available to date for planar, as well as spherical, solitons.
Scattering by a two-layer spherical dielectric object in a lossy medium illuminated by a loop carrying an arbitrary azimuthal mode
Authors: Sebak A. , Shafai L.
Published: April 2011

The electromagnetic response of a circular loop antenna in the vicinity of a two-layer dielectric spherical object located in a lossy medium is investigated analytically. For a loop carrying an azimuthally dependent current distribution, a technique based on the dyadic Green's functions is employed to determine the fields in all regions. The formulation is general and can be applied to a wide variety of electromagnetic sources. Numerical results are presented in the near field zone and at low frequencies to determine the effect of the coating on the scattered field and its influence on the degree of detectability of a coated object.
Gauge-theoretical origin of mechanics
Authors: Vatsya S. R.
Published: April 2011

The momentum of a particle is interpreted as a gauge potential that defines the phase factors and gauge field in terms of the properties of the space–time manifold. Equating the field and the phase factors with the corresponding electromagnetic quantities results in the Lorentz and the Klein–Gordon equation respectively.
Dissociative excitation of CF4 by controlled electron impact
Authors: Wang S. , Forand J. L. , McConkey J. W.
Published: April 2011

Dissociative excitation of CF4 by electron impact has been studied under single-collision conditions for incident energies up to 600 eV. The emission spectrum in the range 50–130 nm shows many features arising from neutral and singly ionized fluorine and carbon fragments. Absolute cross sections for the observed features were measured at 200 eV incident energy, while the excitation functions of the most intense emissions were studied over the whole energy range. Cascade was shown to be the dominant excitation mechanism for some of these features.
The ARCAD-3 project and the theory of auroral structures
Authors: Galperin Yu. I. , Volosevich A. V.
Published: April 2011

Some results of the Soviet–French ARCAD-3 project (AUREOL-3 satellite) are reviewed and discussed. The system of magnetohydrodynamic equations (up to the second moments, neglecting the others), with a rigorous account of all drifts and currents or trapping, in a curved and convergent field tube is derived for a particle population with a bi-Maxwellian particle distribution and with [Formula: see text]. Its first four integrals are derived for a particular case, when spatial variations of the electric field are much more rapid than those of any other macroscopic parameters or their products. This is a realistic condition for an extended stable double layer in an inverted V structure. A specific feature of these integrals is that the polarization-drift effects inherently affect the field-aligned current (FAC) density carried by a particular population if both field-aligned and perpendicular gradients of the electric field are sufficiently high. This is important for double layers extended along the magnetic field in narrow, oblique inverted V's. A three-dimensional geometry of the plasma-sheet pressure gradients [Formula: see text], [Formula: see text] the FAC's, and the polarization and ionospheric closure currents [Formula: see text], and [Formula: see text] is suggested, which is supposed to lead to the formation of a narrow arc at a side of an inverted-V event. Sample calculation results for a two-dimensional geometry in limited areas of the meridional plane with simplest boundary conditions are shown for illustration.
On the influence of the Δ(1232)–hole bubble on the induced interaction
Authors: Bauer E.
Published: April 2011

We present a simple method to deal with the induced interaction when both the Δ–hole bubble and the momentum dependence of the induced interaction are taken into account. Within this approach the Landau–Migdal parameters g′ph and g′ Δh have been estimated.
A spin-two gauge theory
Authors: McKeon D. G. C.
Published: April 2011

We formulate a Lagrangian for a free massless spin-two field hμν that is invariant under the transformation hμν→hμν + ∂μfν + ∂νfμ This is then coupled to a massive scalar field [Formula: see text]. In two dimensions the classical Lagrangian for hμν vanishes identically, and hence the kinetic term in the effective Lagrangian for hμν reduces to the gauge fixing Lagrangian. The theory is renormalizable in two dimensions provided we mix all operators of the form [Formula: see text]. One-loop two-point functions are computed using operator regularization.
Evaluation of a class of integrals occurring in mathematical physics via a higher order generalization of the principal value
Authors: Davies K. T. R. , Davies R. W.
Published: April 2011

The notion of the principal value of an integral is generalized to treat higher order singularities. The principal value of an integral can be considered the "convergent part" of a divergent integral, an interpretation that is almost trivial for simple poles, but more meaningful for higher order poles. Application of this concept leads to a simple algorithm that may be applied to the evaluation of a class of integrals arising in mathematical physics. Many of these integrals frequently occur in the analytic and numerical evaluation of folding functions arising from the product of single-particle Green's functions.
Nuclear tests of fundamental interactions
Authors: McDonald A. B.
Published: April 2011

Measurements of parity violation in nuclei can determine properties of the basic weak nucleon–nucleon interaction, thereby testing electroweak theory and quark models of nucleons. Experiments observing parity violation in the photodisintegration of deuterium, in the scattering of protons from hydrogen, and in the emission of circularly polarized γ rays from 18F are described. A new technique for polarizing 3He is described, and the use of polarized 3He in measurements of parity and time reversal violation is presented. Finally, new directions in γ-ray spectroscopy are illustrated by the Sudbury Neutrino Observatory and new ultrahigh resolution bolometric detectors.
Compton scattering and the MacKenzie spectrometer
Authors: Williams Brian G.
Published: April 2011

The development of the MacKenzie γ-ray Compton scattering spectrometer is discussed in the context of earlier designs to bring out the advantages that it offers over alternative systems. The importance of the new spectrometer in providing the first accurate measurements of γ-ray Raman scattering and the role of Innes MacKenzie in the discovery of γ -ray Raman scattering are discussed. Finally, the potential of the MacKenzie spectrometer design to provide a field fluorescence spectrometer for use in geophysics is described.
The study of atomic inner shell transitions using solid state X-ray spectrometers
Authors: Campbell J. L.
Published: April 2011

The classical measurements of relative X-ray intensities from inner-shell transitions were accomplished with crystal spectrometers. Here we describe more recent work using solid state energy-dispersive detectors, which have much poorer resolution but offer the possibilities of very high counting statistics and very accurate determination of the experimental resolution function. Results for K X-rays agree well with theory, except in the atomic number region where the 3d shell is only partly filled. X-ray techniques can also be used in indirect but rather precise measurements of nonradiative processes. Our data for the L2–L3 Coster–Kronig vacancy transfer probability indicate a systematic departure from theory, likely due to the neglect of the final state interaction effects in the single-particle treatment when an electron is ejected during vacancy de-excitation.
Positron spectroscopy of bulk and near-surface defects in semiconductors
Authors: Hautojārvi P.
Published: April 2011

The use of positron annihilation to study defects in semiconductors is discussed. Positron-lifetime spectroscopy reveals As vacancies in as-grown GaAs and gives information on ionization levels. The vacancy profiles in ion-implanted Si are investigated by slow positron beam.
Énergie localisée autour d'un guide à ondes de surface pour un mode HE11
Authors: Wick A. , Zepp G. , Boubakra A. , Fabre G. , Ritoux G.
Published: April 2011

We have studied the localization of the energy carried by an electromagnetic wave of the HE11 type propagated at the surface of a cylindrical conductor coated with two dielectrics. The influence of different parameters on the energy localization around the conductor is shown.
Nonequilibrium effects in α-particle induced reactions on gallium isotopes
Authors: Rizvi I. A. , Bhardwaj M. K. , Ansari M. Afzal , Chaubey A. K.
Published: April 2011

The stacked foil activation technique and Ge(Li) γ-ray spectroscopy have been employed for the determination of the excitation functions, up to 60 MeV, of six reactions, 69Ga(α,n), (α,2n), (α,3n), (α,p3n); 71Ga(α,n) and (α,4n). Since natural gallium used as the target has two odd-mass stable isotopes of abundance, 69Ga(60.1%) and 71Ga(39.9%), their activation in some cases gives the same residual nucleus through different reaction channels, but with very different Q values. In such cases, the individual reaction cross sections are separated with the help of the ratio of their theoretical cross sections. A preliminary theoretical comparison with the preequilibrium geometry-dependent hybrid (GDH) model has been done using an initial exciton number no = 4 (2n + 2p + 0h), and general agreement was found for all reactions at high energies.
A note on linear action at a distance interaction and the possibility of its deterministic reformulation
Authors: Weiss J.
Published: April 2011

It is shown that the linear action at a distance interaction can be transposed on the basis that allows the deterministic interpretation. The proof is carried out directly in terms of the Θ-function Lagrangian, which generates this interaction. The appropriate interaction terms in the Lagrangian are computed to the third order of the relativistic power-series expansion for an examined two-particle system.
A representation of the boundary condition for the macroscopic magnetic field intensity
Authors: Delecki Z. A.
Published: April 2011

An explicit formula is derived for the surface-current density in terms of the constitutive parameters of the dielectric media adjacent to both sides of the boundary surface. The concepts of the transverse-longitudinal decomposition of electromagnetic fields and the intrinsic impedance for a homogeneous medium are used. The limiting procedure is applied to represent the transverse fields and currents at the interface of two different media.
Ising model critical exponent η from a criticality equation
Authors: Frank B. , Macot L. , Bassias K. V. , Danino M.
Published: April 2011

A pair-correlation function ansatz, previously used in the derivation of the Ising model critical exponent η for the square lattice from a criticality equation within the i-δ approximation, is investigated further. Various methods are used to calculate the multispin correlation functions entering the criticality equation. The calculations are extended to the three-dimensional cubic lattices. It is found that the values obtained for η are relatively insensitive to the specific method used. In two dimensions, η takes the values 0.2506 (i-δ method), 0.2471, and 0.2490 (renormalized Hamiltonian methods), thereby remaining within 1.2% of the exact value 1/4. In three dimensions, η ranges from 0.030 to 0.075, being of the same order of magnitude as the series value 0.041 ± 0.01.
Étude expérimentale de propriétés piezo-optiques du CS2 en phase liquide à 273,15 et 298,15 K pour des pressions jusqu'à 140 MPa
Authors: Guerfi A. , St-Arnaud J. M.
Published: April 2011

Using a Michelson interferometer coupled to a stabilised He–Ne laser, we measured the change of the refractive index of liquid CS2 along two isotherms, 273.15 and 298.15 K for pressures up to 140 MPa. Results show that the classical Lorentz–Lorenz equation versus the pressure varies linearly, as predicted by classical theory. Results also show that for liquid CS2 the experimental value of (8.4 ± 0.5) × 10−24 cm3, for the electronic polarizability in the range studied, is constant with pressure and temperature. Our experimental value of 8.74 × 10−24 cm3 for the electronic polarizability agrees with that found in the literature.
Spectroscopic constants and potential-energy derivatives for diatomic molecules of alkali halides
Authors: Sangachin A. A. S. , Shanker J.
Published: April 2011

The potential-energy derivatives are derived directly from the experimental values of the spectroscopic constants for diatomic alkali halides. It is found that these derivatives are useful in predicting more accurately the values of the higher order spectroscopic constant (βe). Some interesting new relations showing the dependence of the potential-energy derivatives on internuclear distances have been investigated empirically. An attempt has been made to interpret these relations on the basis of interionic potentials.
Two-photon laser excitation of 2p5(2P1/2) 3d levels of neon
Authors: García G. , Ortiz M. , Blanco F. , Sánchez J. A. , Campos J.
Published: April 2011

A pulsed two-photon excitation of the 2p5(2P1/2) 3d levels of Ne (3d′ levels), from the metastable 3s(3/2)2 state, was made to measure their lifetimes. The experimental results of this work are 20.1 ± 0.3 and 19.6 ± 0.9 ns for the 3d′(3/2)2 and 3d′ (5/2)2 levels, respectively.
Bound states of spinless particles with Coulomb interaction in the momentum representation
Authors: Domínguez-adame F.
Published: April 2011

Bound-state solutions of the Klein–Gordon Coulomb equation for vector and scalar potentials are investigated in the momentum representation. The collapse of the particle to the center for strong vector potentials is found. The corresponding wave function shows an anomalous oscillatory behaviour for large particle momentum. Particle collapse for strong scalar potentials does not exist.