Formation of a two-dimensional periodic structure of local melting regions on a silicon surface upon pulsed light irradiation

The first results regarding the formation of a two-dimensional periodic structure of local melting regions on a silicon surface upon pulsed light irradiation are presented. The conditions are established, and the mechanism of the formation of such structures is discussed. Zh. Tekh. Fiz. 67, 97–99 (December 1997)     

Excitation of bulk elastic waves at the surfaces of piezoelectric crystals with 422,622 symmetry

The problem of exciting bulk elastic waves at the surface of a piezoelectric with symmetries 422,622 has been solved by a successive approximation method. In the approximation of a fixed electric field, created at the surface of the piezoelectric crystal by a two-electrode transducer, the distributions are found for the shear wave stress and the energy flux density in the far zone. The equivalent circuit parameters for a two-electrode radiator are determined taking account of the dynamic piezoelectric correction obtained in the second approximation. The equivalent circuit parameters and the transducer loss are treated for TeO₂ crystals. A realistic possibility of using surface transducers in the development of acousto-optic modulators in the s.h.f. region is shown. Tomsk State Academy of Control Systems and Radio Electronics. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 8–15, January, 1997.     

Thermodynamic stability of the structure of a deformed Fe-C solid solution

An analysis is made of the thermodynamic stability of the dislocation structure in polycrystalline samples of Fe-C, deformed under conditions of high rates and hydrostatic pressures, based on experimental and theoretical data concerning the internal energy and on diffractometer measurements of the broadening of x-ray lines. The method of deformation calorimetry was used to determine the internal energy in a wide range of deformations. A theoretical model is proposed for estimating the change in internal energy in deformed alloys. An investigation is made of the dependence of the interdislocation interaction parameter on the deformation rate for different stressed state-schemes and large plastic deformations. It is shown that the relative quantity δU/A is correlated in a wide range of deformations with the relative root-mean-square distortions of the crystal lattice of the deformed solid solution. The mechanisms for the accumulation of energy in deformed solid solutions having a body-centered cubic lattice are considered. Don State Technical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 77–83.     

Student-Invented Numeration Systems: Pattern-Analysis and Mathematical Understanding

Thirteen fifth graders were given an assignment to invent their own numeration systems, following a unit on bases and a look at early events in the history of numbers. The task presented options that required the students to make decisions (such as whether to use a base, which base to use, design of symbols, etc.), and build a rationale for the elements of their system. Analyses of patterns embedded in their invented systems provided an assessment of student understanding of numeration. The progression of more and less complex thinking related to the student's choice of a base other than 10, consistency of logic throughout the system in words and symbols, rationale for change, and perception of real life examples that would change if the system was adopted. The invention task is presented as another way to make connections.     

Increasing the accuracy of eigenvalue computation in the spectral problem

A simple method is proposed for increasing the accuracy of computation of the eigenvalues of elliptic operators, which does not require high-order accurate schemes.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 63, pp. 63–68, 1987.     

Investigation of the conditions for feeding filamentary silicon crystals,growing in a reactor with hot walls

An estimate of the factors which influence the rate of growth of filamentary silicon crystals in a standard chloride system using a quartz reactor with hot walls is given. It is shown that a diffusion form of crystallization is observed under the conditions investigated.Voronezh State Technical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 22–26, October, 1995.     

Integration of the equations of planar and flexural vibrations of anisotropic plates in special functions of generalized complex variables

On the basis of the method of successive approximations in formal series we construct systems of particular solutions of the equations of planar and flexural harmonic vibrations of thin rectilinear anisotropic plates with a plane of symmetry of elastic properties parallel to the faces. The solutions constructed are classified as special sk-functions of generalized complex variables. Translated fromTeoreticheskaya i Prikladnaya Mekhanika No. 24, 1993, pp. 54–61.     

Radiation bursts from particles in the field of compact, impenetrable, astrophysical objects

The radiation emitted by charged, scalar particles in a Schwarzschild field with maximal acceleration corrections is calculated classically and in the tree approximation of quantum field theory. In both instances the particles emit radiation that has characteristics similar to those of gamma-ray bursters.