Crystal electric field effects in Pr0.5Sr0.5CoO3

The energy structure and temperature evolution of the magnetic excitation spectra of Pr_0.5Sr_0.5CoO₃ are studied by inelastic neutron scattering. The measurements are performed on a polycrystalline sample of Pr_0.5Sr_0.5CoO₃ and its non-magnetic analogue La_0.5Sr_0.5CoO₃ on the high intensity time-of-flight spectrometer IN4 (ILL, Grenoble) in the temperature range 10 K < T < 300 K. The crystal electric field parameters in Pr_0.5Sr_0.5CoO₃ are calculated and the splitting scheme of the 4f ground multiplet of Pr³⁺ ions is determined based on the experimental data.     

Electron work function of LaNi5 ? x T x (T = Al, Cu, Fe; x = 0, 1) intermetallics

The method of contact potential difference is applied to determine the electron work function of ingots and pellets (compacted powder) of LaNi_{5 ? x} T _x (T = Al, Cu, Fe; x = 0, 1) intermetallics at 293 K. A correlation is revealed between the electron work function and the heats of formation of the intermetallics and their hydrides.     

Applying scattered-ion spectroscopy to the analyzing of plasma-surface interactions

A setup based on an ion mass monochromator and intended for investigating plasma interactions with surfaces of plasma facility materials is described. It analyzes the composition and thickness of surface films by means of ion scattering spectroscopy. An analysis of the composition of stainless steel and graphite is performed using helium and argon ions in the range of 2?C8 keV. The obtained results demonstrate the possibility of investigating the dynamics of carbon and oxygen behavior on the surface of materials using negatively charged recoil ions and scattered helium ions.     

Electron-beam surface treatment of alloys based on titanium, modified by plasma from an electrical explosion of conducting material

We present the results from investigating the phase composition, structure, and properties of surface layers of titanium alloys subjected to combined treatment that includes plasma alloying the electric explosion of a carbon fiber with a quantity of TiB₂ powder and subsequent irradiation with a high-intensity electron beam. The formation of a multilayer, multiphase structure in the submicro- and nano-sized ranges is observed. It is shown that the properties of a alloyed layer exceed those of a bulk sample many times over.     

Reinvestigation of the decay scheme of the short-lived isomeric states in112In

The two short-lived isomeric states in¹¹²In have been reinvestigated by means of the¹¹²Cd(d, 2n) and¹⁰⁹Ag (α, n) reactions. Measurements of delayed X- andγ-ray, lifetime and TDPAD spectra have been performed. A 6.32(3) keVγ-ray has been identified in the isomeric decay and anM1 multipolarity has been assigned to it on the basis of the measured internal conversion coefficients:α _L =196(39) andα _tot=231(35). TheE1+M2(δ =+0.24(4)) andE2 multipolarities have been determined for the 263 and 188 keV transitions deexciting the 8^?(T _1/2=2.82(2) μs) and 7⁺ (T _1/2=0.93(2) μs) isomeric states, respectively. A revised isomeric decay scheme is presented.     

Electromagnetic moments and nuclear charge radii for neutron-deficient Tb isotopes and the deformation jump nearZ=64,N=90

Optical isotope shifts and hyperfine structures of the^{147–153,155,157,159} Tb isotopes have been measured by the resonance ionization spectroscopy method. Nuclear moments and changes in nuclear charge radiiΔ 〈r ²〉 have been deduced. The “jump” inΔ 〈r ²〉 atN=88–90 has been revealed. It is compared with the relevant data for nuclei with other proton numbers.     

Quasielastic nucleon and hyperon production by neutrinos and antineutrinos with energies below 30 GeV

The cross sections of neutrino and antineutrino quasielastic reactions \(vn \to \mu ^ - p,\bar vp \to \mu ^ + n,\bar vp \to \mu ^ + \Lambda\) were studied in the neutrino energy range between 3 and 30 GeV. In comparison withV-A theory axial mass parameters ofM _A =(1.06±0.05±0.14) GeV/c² from neutrino andM _A =(0.71±0.10±0.20) GeV/c² from antineutrino data were found. The total cross-section for the hyperon production process can be described byM _A =1.0 GeV/c².     

Rational functions of best uniform approximation and holomorphic continuation of functions

Let f be a function, continuous and real valued on the segment Δ, Δ ⊂ (−∞, ∞) and {R_n} be the sequence of the rational functions of best uniform approximation to f on Δ of order (n, n). In the present work, the convergence of {R_n} in the complex plane is considered for the special caseswhen the poles (or the zeros, respectively) of {R_n} accumulate in the terms of weak convergence of measures to acompact set of zero capacity. As a consequence, sufficient conditions for the holomorphic and the meromorphic continuability of f are given. The work is supported by Project 69 with Ministry of Science and Education, Bulgaria.     

The Nambu–Jona–Lasinio model of light nuclei

The Nambu–Jona–Lasinio model of the deuteron suggested by Nambu and Jona–Lasinio (Phys. Rev. 124 (1961) 246) is formulated from the first principles of QCD. The deuteron appears as a neutron–proton collective excitation, i.e. a Cooper np–pair, induced by a phenomenological local four–nucleon interaction in the nuclear phase of QCD. The model describes the deuteron coupled to itself, nucleons and other particles through one–nucleon loop exchanges providing a minimal transfer of nucleon flavours from initial to final nuclear states and accounting for contributions of nucleon–loop anomalies which are completely determined by one–nucleon loop diagrams. The dominance of contributions of nucleon–loop anomalies to effective Lagrangians of low–energy nuclear interactions is justified in the large N _C expansion, where N _C is the number of quark colours. Received: 10 March 2000     

The network approach to calculation of characteristic time constants of the flat two-layer superconducting cable

The matrix method was used to investigate the process of current decay in the samples of flat two-layer superconducting cables. The discrete spectrum of eigen-frequencies has been obtained. Each of these frequencies determines the rate of decay of the correspondent eigen-current. Despite of the increasing of the number of eigen-frequencies with the enlargement of the sample dimensions the spectrum remains finite, as the maximum and minimum frequencies tend to finite limits. An analysis made for the lowest eigen-frequencies showed the corresponding eigen-currents to be slowly decaying long current loops. Within the range of high frequencies the sinusoidal distribution of eigen-currents in the rows of the cable was observed.