Relativistic form factor in terms of wave functions of composite systems at rest

Joint Institute for Nuclear Research, Dubna. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 78, no. 2, pp. 227–233, February, 1989.     

Phase composition and properties of superconducting ceramics based on Bi1.7Pb0.3Sr2Ca2Cu3Oy precursors fabricated by melt quenching in a solar furnace

Production of superconducting ceramics based on precursors with rated composition Bi_1.7Pb_0.3Sr₂Ca₂Cu₃O _y is studied. The precursors are synthesized in a solar furnace by melt rapid quenching. The phase composition of the samples is examined by microstructural and X-ray analyses. The temperature dependences of the resistance and magnetic susceptibility are measured. The influence of the composition and crystal structure of the substrate on texturing in the Bi-Sr-Ca-Cu-O system is studied. It is found that the type of quenching plays a significant role, while the type of substrate is of minor significance.     

Explicit Expressions for Timelike and Spacelike Observables of Quantum Chromodynamics in Analytic Perturbation Theory

We study the possibility of expressing the invariant QCD coupling function (i.e., the effective coupling constant) in an explicit analytic form in two- and three-loop approximations as well as in the case of the Padé-transformed -function. Both the timelike and spacelike domains are investigated. Technical aspects of the Shirkov–Solovtsov analytic perturbation theory are considered. Explicit expressions for the two- and three-loop effective coupling functions in the timelike domain are obtained. In the last case, we apply a new method of expanding functions represented in an arbitrary loop order of perturbation theory in powers of the two-loop function. The comparison with numerical data in the infrared region shows that the obtained explicit expressions for the three-loop functions agree fully with the exact numerical results.     

Effect of anisotropy on the mechanical properties and morphology of necks in the orientation of high-pressure polyethylene

The mechanical properties and changes in supermolecular structure during the reorientation of anisotropic polyethylene at various values of the angle between the directions of orientation and tension () were investigated. By comparing the microscopic and dynamometric data it was established that the tension diagrams often have a different physical significance from the usual. It is shown that the morphology and mechanism of the structural changes occurring during reorientation are determined by the value of and are independent of the temperature and elongation rate.Institute of Cybernetics, Academy of Sciences of the Georgian SSR, Tbilisi. Translated from Mekhanika Polimerov, No. 6, pp. 967–975, November–December, 1972.     

The Investigation of Critical Temperature Tc of Homophase Superconductors Bi1.7Pb0.3Sr2Ca(n– 1)CunOy (n = 3, 4, 5) and Current–Voltage Characteristics of InP Semiconductor–Bi/Pb Superconductor (2223, 2234, 2245) Sandwich Pairs

Technical Physics - The electrophysical properties of semiconductor–superconductor sandwich pairs (InP–Bi/Pb 2223, 2234, 2245) are investigated, in which homophase superconductors based...     

A study of the radiation environment on board the Space Shuttle flight STS-57

A joint NASA-Russian study of the radiation environment inside a SPACEHAB 2 locker on Space Shuttle flight STS-57 was conducted. The Shuttle flew in a nearly circular orbit of 28.5 degrees inclination and 462 km altitude. The locker carried a charged particle spectrometer, a tissue equivalent proportional counter (TEPC), and two area passive detectors consisting of combined NASA plastic nuclear track detectors (PNTDs) and thermoluminescent detectors (TLDs), and Russian nuclear emulsions, PNTDs and TLDs. All the detector systems were shielded by the same Shuttle mass distribution. This makes possible a direct comparison of the various dose measurement techniques. In addition, measurements of the neutron energy spectrum were made using the proton recoil technique. The results show good agreement between the integral LET spectrum of the combined galactic and trapped particles using the tissue equivalent proportional counter and track detectors between about 15 keV/micrometers and 200 keV/micrometers. The LET spectrum determined from nuclear emulsions was systematically lower by about 50%, possibly due to emulsion fading. The results show that the TEPC measured an absorbed dose 20% higher than the TLDs, due primarily to an increased TEPC response to neutrons and a low sensitivity of TLDs to high LET particles under normal processing techniques. There is a significant flux of high energy neutrons that is currently not taken into consideration in dose equivalent calculations. The results of the analysis of the spectrometer data will be reported separately.     

Testing the Concept of Quark–Hadron Duality with the ALEPH τ Decay Data

We propose a modified procedure for extracting the numerical value for the strong coupling constant α _s from the τ lepton hadronic decay rate into non-strange particles in the vector channel. We employ the concept of the quark–hadron duality specifically, introducing a boundary energy squared s _p > 0, the onset of the perturbative QCD continuum in Minkowski space (Bertlmann et al. in Nucl Phys B 250:61, 1985; de Rafael in An introduction to sum rules in QCD. In: Lectures at the Les Houches Summer School. arXiv: 9802448 [hep-ph], 1997; Peris et al. in JHEP 9805:011, 1998). To approximate the hadronic spectral function in the region s > s _p, we use analytic perturbation theory (APT) up to the fifth order. A new feature of our procedure is that it enables us to extract from the data simultaneously the QCD scale parameter ${\Lambda_{\overline{\rm MS}}}$ and the boundary energy squared s _p. We carefully determine the experimental errors on these parameters which come from the errors on the invariant mass squared distribution. For the ${\overline{\rm MS}}$ scheme coupling constant, we obtain ${\alpha_s(m^{2}_{\tau})=0.3204\pm 0.0159_{exp.}}$ . We show that our numerical analysis is much more stable against higher-order corrections than the standard one. Additionally, we recalculate the “experimental” Adler function in the infrared region using final ALEPH results. The uncertainty on this function is also determined.