Component distribution of the solid solution AlxGa1-xAs during zone melting with a temperature gradient of the powderlike source

The component distribution of the ternary solid solution in epitaxial layers of Al_xGa_1-xAs grown by a zone recrystallization method by a temperature gradient during continuous feed maintenance by a powdery source consisting of a mixture of gallium arsenide and aluminum is analyzed theoretically. The possibility is shown of stationary growth of a material of constant composition as well as of epitaxial layers with controllable growing or decreasing aluminum arsenide distributions in the growth direction.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 52–55, February, 1987.In conclusion, the authors are grateful to V. N. Lozovskii for interest in the research and useful discussions.     

Electroproduction of <Emphasis Type="Italic">J/ψ</Emphasis> mesons within the semihard QCD approach and the color-singlet model

The deep-inelastic production of J/ψ mesons in electron-proton interactions at the HERA collider is considered within the semihard (k_T-factorization) QCD approach and within the color-singlet model. The dependence of the Q², p _T ² , z, y* and W distributions of J/ψ mesons on various sets of unintegrated gluon distributions and the dependence of the spin parameter α on p _T ² and Q² are investigated. The results of the calculations are compared with the latest experimental data obtained by the H1 and ZEUS Collaborations at the HERA collider. It is shown that experimental investigations of the polarization properties of J/ψ mesons over the kinematical region Q²<1 GeV² may provide an additional test of the statement that the dynamics of gluon distributions is governed by the Balitsky-Fadin-Kuraev-Lipatov equations.     

Experimental and theoretical study of the IR spectrum and barriers to internal rotation of 4-hydroxypropyl-4′-cyanobiphenyl

The IR absorption spectrum of polycrystalline 4-hydroxypropyl-4′-cyanobiphenyl is measured in a KBr pellet over the range 400–4000 cm^?1. The structure of the molecule and the frequencies and the intensities of the bands in the spectrum are calculated in the approximation of the B3LYP hybrid density functional with the 6-31 G(d) and 6-31+G(d) basis sets. The normal vibrations are reliably assigned by the method of linear scaling of frequencies, which made it possible to reproduce the experimental IR spectrum with high accuracy. The barriers to internal rotation of phenyl rings and three barriers for the hydroxypropyl radical are calculated.     

Doping of magic nanoclusters in the submonolayer In/Si(100) system

Si(100)4 x 3-In reconstruction is essentially a superlattice of magic (identical-size) Si7In6 nanoclusters. Using scanning tunneling microscopy (STM) observations, we have found that under appropriate growth conditions up to 35% of these clusters can be modified; namely, two Si atoms in the cluster can be replaced by two In atoms, thus forming a Si5In8 cluster. This modification can be considered as a doping of the magic cluster, as it changes the electronic properties of the cluster from semiconducting towards metallic. The doped cluster is less rigid than the ordinary one and swings in the electrical field of the STM tip. The atomic structure and stability of the doped magic cluster have been examined using first-principles total-energy calculations.     

Synthesis of 2, 6-derivatives of 1, 4-dioxane

Stereoisomers of 6-halomethyl-2-hydroxymethyl-1, 4-dioxanes have been obtained via the cyclization of the monoallyl ether of glycerol. The stereoisomeric bromides differ considerably in their physical properties. The bromine atoms of the stereoisomers differ in their reactivity towards thiourea.     

Generation of Craze-Formation Centers in Polymer Films under the Action of Electric Discharge Plasma

We propose a technology for generating craze-formation centers in polymers under the action of the electric discharge plasma and consider questions associated with a method for varying the geometrical sizes of crazes. The possibility of obtaining nanostructured polymers are also considered.