Characterization of III–V compounds by quasi-elastic electronic scattering of light

Quasi-elastic light scattering from individual electron single-particle excitations is observed experimentally and studied theoretically in n-GaAs and n-InP samples with nonparabolic dispersion of energy bands for a wide range of free-electron concentrations varying from ≈10⁸ to ≈10¹⁹ cm^-3. The results indicate that the scattering mechanisms associated with charge-, spin- and momentum-density fluctuations are represented by different light scattering line shapes and occur in different concentration ranges.     

Polymorphic Transformations in the K0.945Ag0.055NO3 Single Crystal

Crystallography Reports - The polymorphic transformations in K0.945Ag0.055NO3 are studied by optical spectroscopy and X-ray diffraction. It is established that one structural transformation occurs...     

Uniform convergence and numerical computation of the Hubbell radiation rectangular source integral

In this paper, we investigate uniform convergence of the improper Hubbell radiation rectangular source (HRS) integral H(a,b). We prove that HRS integral H(a,b) is uniform convergent in the domain D?{(a,b)∈[0,A]×[0,∞)} for any positive finite number A. Then we give an accurate and efficient computation algorithm for the HRS integral.     

Uniform convergence and the properties of the exponential and generalized exponential integral functions

The exponential integral function (EIF) and the generalized exponential integral function (GEIF) are defined as

     

Parallel and k-out-of-n: G systems with nonidentical components and their mean residual life functions

A system with n independent components which has a k-out-of-n: G structure operates if at least k components operate. Parallel systems are 1-out-of-n: G systems, that is, the system goes out of service when all of its components fail. This paper investigates the mean residual life function of systems with independent and nonidentically distributed components. Some examples related to some lifetime distribution functions are given. We present a numerical example for evaluating the relationship between the mean residual life of the k-out-of-n: G system and that of its components.     

Di(4-isopropenylphenoxy)alkanes as cross-linking comonomers in three-dimensional copolymerization with styrene

Di(4-isopropenylphenoxy)alkanes were synthesized by condensation of 4-isopropenylphenol with symmetrical dihaloalkanes in the presence of KI promoter. Three-dimensional polymeric structures were prepared by compolymerization of these monomers with styrene.     

Optoelectronic effects in p-CdGeAs2 single crystals and structures based on them

Spectra of inelastic light scattering by optical phonons in p-CdGeAs₂ single crystals were obtained for the first time. The observed clear polarization dependence and the absence of any appreciable dependence of the intensity and frequency of the observed lines when the sample is swept in ≈300 μm steps indicates these CdGeAs₂ single crystals grown by directional crystallization from a near-stoichiometric flux, are of high quality and homogeneous. The type of symmetry of the observed phonon lines is interpreted and it is shown that the force constants in CdGeAs₂ and CdSnP₂ crystals differ slightly. Temperature dependences of the electrical conductivity and the Hall constant were studied in oriented homogeneous p-CdGeAs₂ single crystals. It was established that the conductivity of these crystals is determined by the deep acceptor level E _A=0.175 eV and has the degree of compensation 0.5–0.6. The temperature dependence of the Hall mobility reflects the competition between impurity and lattice mechanisms of hole scattering. The photosensitivity of In/CdGeAs₂ surface barrier structures reaches 20 μA/W at T=300 K and remains at this level within the fundamental absorption of CdGeAs₂. It is concluded that these structures may be used as wide-band photoconverters for natural light and as selective photoanalyzers for linearly polarized radiation. Fiz. Tverd. Tela (St. Petersburg) 40, 212–216 (February 1998)     

Stability and estimation of the transient in systems with distributed parameters

Kazan Aviation Institute. Kamsk Polytechnic Institute, Naberezhnye Chelny. Translated from Prikadnaya Mekhanika, Vol. 27, No. 2, pp. 106–113, February, 1991.     

Effect of annealing in vacuum on the magnetic anisotropy of Ag-doped CdCr2Se4 crystals

Angular dependences of resonance field and linewidth have been measured for ferromagnetic CdCr₂Se₄ crystal doped with 1.5 mol.% Ag before and after annealing in vacuum. The change of the sign of anisotropy due to annealing is associated with transformations Cr⁴⁺→Cr³⁺→Cr²⁺. On the basis of obtained data some suppositions are made about the mechanisms of conductivity in the Ag-doped CdCr₂Se₄ crystal.