Microscopic calculations of charge-exchange nuclear modes

Microscopic calculations of nuclear states excited by means of charge-exchange reactions and involving spin and isospin degrees of freedom, in particular, of the Gamow—Teller and the spin—dipole resonances, are discussed. The framework is a fully self-consistent nonrelativistic spherical quasiparticle random-phase approximation constructed on top of the Hartree—Fock—Bardeen—Cooper—Schrieffer approach. Our results are compared with available experimental data, and a critical discussion is attempted. The text was submitted by the authors in English.     

Glow-discharge-pumped broadband ultraviolet lamp

The optical characteristics of a UV broadband lamp that was excited by a longitudinal glow discharge and operated on Kr—Br₂—I₂, Xe—Br₂—I₂, and Kr—Xe—Br₂—I₂ mixtures are investigated. The interelectrode spacing in the lamp is 10 cm, the inner diameter of a discharge tube being 14 mm. The current-voltage characteristics, the emission spectra of the plasma, and the dependence of the intensity of spectral lines (the amplitude of radiation bands) on the power that was pumped into the plasma based on mixtures of various compositions and pressures, as well as the radiation power in the spectral range from 200 to 390 nm, are studied. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 840–842, November–December, 2005.     

Structure of zinc-borate low-melting glasses derived from IR spectroscopy data

The IR spectra of glasses of the ZnO—SrO—B₂O₃ system with constant additions of PbO, Al₂O₃, and Li₂O (20 mol. % in sum) were studied. It is established that on replacement of B₂O₃ by ZnO, the structure of the glasses is characterized by the presence of groupings with the bridge bonds B^III— O—B^III, B^III—O—B^IV, B^IV—O—B^IV and end groups B^III— O⁻; ZnO practically exerts no influence on the coordination transition [BO₃] → [BO₄]. At a high content of ZnO, zinc ions are present in both a six-and a four-coordinated state. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 778–781, November–December, 2005.     

Constructing lie algebras of first-order differential operators

Formulas for calculating vector fields — generators of groups of transformations to a uniform space — from specified structural constants are obtained. The problem of vector-field continuation — the construction of Lie algebras of inhomogeneous first-order differential operators — is considered. It is also shown that the existence of a nontrivial continuation is closely associated with the structure of the isotopic subalgebra and, in particular, that no nontrivial continuation exists for semisimple algebras. Omsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 25–32, June, 1997.     

Reflection of the dynamics of interplanetary space parameters in the maximum observable frequencies on different ionospheric oblique-sounding paths

We study the correlation between variations in the solar–geophysical parameters and variations in the maximum observable frequencies (MOF) on several ionospheric short-wave oblique-sounding paths. The basic interplanetary space parameters, whose variations have the greatest impact on the MOF variations on specified paths, are determined. Variations in the B_x and B_z components of the interplanetary magnetic field (IMF) affect the MOFs on the Norilsk—Rostov-on-Don subauroral path. At mid-latitudes, the influence of the IMF components B_x, B_y, and B_z is significant on the Inskip—Rostov-on-Don and Irkutsk—Rostov-on-Don paths. On the Cyprus—Rostov-on-Don low-latitude path, the modulus of the IMF has the most pronounced effect. The density and velocity of solar wind manifest themselves in MOF variations on all paths. The technique of MOF retrieval by a neural network on the Cyprus—Rostov-on-Don and Irkutsk—Rostov-on-Don paths using the MOF data of the Inskip—Rostov-on-Don path is developed with allowance for the influence of the interplanetary space parameters. The retrieval efficiency of this technique is no less than 80%.     

Equivalent network parameters of millimeter wave E-plane septum discontinuities with finite conductivity

The equivalent T—network parameters of millimeter wave E—plane discontinuities of bilateral metal septa with finite conductivity are calculated by the method of lines. An efficient approach is presented to extend this numerical method to EM boundary value problems with imperfectly conducting metal boundaries parallel to the discretization lines. Numerical results of both equivalent reactances and resistances in the T—network are obtained. The insertion losses of a Ka—band filter are calculated based on the lossy equivalent circuit. Numerical results are in agreement with the published experimental results.     

A complete data base of kinematical data for early-type galaxies

Summary As a result of an exhaustive bibliographical search covering the period 1975–1988, a complete catalogue of kinematical data for early-type galaxies (ellipticals and lenticulars) has been compiled. The catalogue contains all data—both in tabular and in plotted form—appeared in specialized literature before December 1988 and includes central velocity dispersions, rotation curves, and velocity dispersion profiles for 846, 174 and 108 objects, respectively. The catalogue is also available on magnetic tape—made available to the astronomical community through the Strasbourg Data Center—and will be updated yearly. To speed up publication, the proofs were not sent to the authors and were supervised by the Scientific Committee.     

Dynamic oversight: implementation gaps and challenges

Nanotechnology is touted as a transformative technology in that it is predicted to improve many aspects of human life. There are hundreds of products in the market that utilize nanostructures in their design, such as composite materials made out of carbon or metal oxides. Potential risks to consumers, to the environment, and to workers from the most common passive nanomaterial—carbon nanotubes—are emerging through scientific research. Newer more active nanostructures—such as cancer therapies and targeted drug systems—are also increasing in use and are raising similar risk concerns. Governing the risks to workers is the subject of this commentary. The Occupational Safety and Health Act of 1970 grants the Occupational Safety and Health Administration the legal authority to set occupational health standards to insure that no worker suffers material impairment of health from work. However, setting a standard to protect workers from nanotechnology risks may occur some time in the future because the risks to workers have not been well characterized scientifically. Alternative risk governances—such as dynamic oversight through stakeholder partnerships, “soft law” approaches, and national adoption of international consensus standards—are evaluated in this article.     

The influence of radiation heat exchange on characteristics of liquid fuel ignition by a heated metal particle

A complex of interrelated heat-mass transfer processes at gas-phase ignition of a typical liquid fuel by a hot metal particle immersed partially into a liquid is investigated numerically. The scale of influence of the radiation heat exchange at particle—liquid fuel and particle—gas—vapor mixture interfaces is found. Conditions under which the impact of this factor can be neglected are determined.     

Some top-quark propertie s mea sured in $$p\bar p$$ colli sion s u sing CDF detector at √ s = 1.96 TeV (Review)

This review considers important properties of the top-quark. The top-quark decays before hadronization, and the spin information is directly transferred to the decay products. Therefore the structure of the weak interaction is investigated by measuring the helicity fractions, f, of the W boson—the top-quark decay product. Other investigations: search for the presence of V+A interaction, search for exotic top-quark charge — 4/3 and for t[`(t)]t\bar t — resonances—all of them, so far, were not found in the experiments — testifies against of going out of the Standard Model.     

Superintegrability on N-dimensional spaces of constant curvature from so(N + 1) and its contractions

The Lie—Poisson algebra so(N + 1) and some of its contractions are used to construct a family of superintegrable Hamiltonians on the N-dimensional spherical, Euclidean, hyperbolic, Minkowskian, and (anti-)de Sitter spaces. We firstly present a Hamiltonian which is a superposition of an arbitrary central potential with N arbitrary centrifugal terms. Such a system is quasi-maximally superintegrable since this is endowed with 2N — 3 functionally independent constants of motion (plus the Hamiltonian). Secondly, we identify two maximally superintegrable Hamiltonians by choosing a specific central potential and finding at the same time the remaining integral. The former is the generalization of the Smorodinsky—Winternitz system to the above six spaces, while the latter is a generalization of the Kepler—Coulomb potential, for which the Laplace—Runge—Lenz N vector is also given. All the systems and constants of motion are explicitly expressed in a unified form in terms of ambient and polar coordinates as they are parametrized by two contraction parameters (curvature and signature of the metric). The text was submitted by the authors in English.     

Molecular structures and stratification in a 2-butanol—water system

The results of investigation of the spectra of 2-butanol in CCl₄, pure 2-butanol, and a 2-butanol— water mixture in the region of the second overtone of the stretching O—H vibration are presented. The assignment of the bands of the overtones is performed. The role of various associates in the processes of stratification in the 2-butanol—water system is discussed. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 837–839, November–December, 2005.     

Random matrix theories and exactly solvable models

A connection between random-matrix theories and exactly solvable models is discussed here. This is done in three parts: firstly, for theWigner—Dyson case; secondly, for the short-range Dyson case; and thirdly, for the pseudo-Hermitian one. The exactly solvable models are variants and extensions of Calogero—Sutherland—Moser systems.     

Positron polarization in chiral media

Summary The positron spin depolarization, relative to the direction of a static magnetic field, was investigated in some chiral media where Ps formation occurs. The results indicate that helical positrons are able to distinguish one enantiomer from the other: the remaining polarizations—just before Ps is formed—differ by about 20% on passing from one enantiomer to the other of the same chiral species. Moreover the existence of a process—strictly connected with chirality and able to hinder any depolarizing process more efficiently than the field itself—has been made evident at low fields. This work was supported by INFM (Consorzio Nazionale di Fisica della Materia).     

Photoconversion and photocatalytic activity of uranyl in acetone solutions

We have studied the effect of irradiation on the uranyl nitrate — acetone and uranyl perchlorate — acetone systems. We have established that when the uranyl perchlorate — acetone system is irradiated, polymerization of the acetone occurs and the catalyst for the process is excited uranyl complexes. In the polymer, uranium is found in the form of nanoclusters of pentavalent and tetravalent uranium, formed as a result of photochemical reactions. Polymerization does not occur in the uranyl nitrate — acetone system. We consider possible factors responsible for the noted differences. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 5, pp. 565–568, September–October, 2007.     

Cosmic rays in the heliosphere

Summary This is a rapporteur paper for the XXIV International Cosmic-Ray Conference covering topics of anomalous cosmic rays, shock acceleration, modulation and transport theory, cosmic-ray gradients, corotating interaction regions, coronal-mass ejections, and solar neutrinos. Among the highlights of the meeting are —conclusive proof that most anomalous cosmic rays are singly charged,—undisputed detection of anomalous cosmic-ray hydrogen,—discovery of unexpectedly large anisotropies of pickup ions,—observation of pronounced solar rotational modulation of cosmic-ray fluxes to the highest heliolatitudes (∼80°) probed by the Ulysses spacecraft, and—new measurements of modulation effects sensitive to particle charge sign. Rapporteur talk given at the XXIV International Cosmic-Ray Conference, Rome, August 28–September 8, 1995.     

Cosmic microwave background and first molecules in the early universe

Besides the Hubble expansion of the universe, the main evidence in favor of the big-bang theory was the discovery, by Penzias and Wilson, of the cosmic microwave background (hereafter CMB) radiation. In 1990, the COBE satellite (Cosmic Background Explorer) revealed an accurate black-body behavior with a temperature around 2.7 K. Although the microwave background is very smooth, the COBE satellite did detect small variations—at the level of one part in 100 000—in the temperature of the CMB from place to place in the sky. These ripples are caused by acoustic oscillations in the primordial plasma. While COBE was only sensitive to long-wavelength waves, the Wilkinson Microwave Anisotropy Probe (WMAP)—with its much higher resolution—reveals that the CMB temperature variations follow the distinctive pattern predicted by cosmological theory. Moreover, the existence of the microwave background allows cosmologists to deduce the conditions present in the early stages of the big bang and, in particular, helps to account for the chemistry of the universe. This report summarizes the latest measurements and studies of the CMB with the new calculations about the formation of primordial molecules. The PLANCK mission—planned to be launched in 2009—is also presented.