Thickness of the damaged layer along the track made by a high-energy ion in polyimide

The thickness of the damaged layer along a particle track in polyimide is estimated by the method of thermally stimulated exoelectron emission and found to be ∼30 nm. Pis’ma Zh. Tekh. Fiz. 23, 68–71 (December 12, 1997)     

Optical method of determining the components of the relative displacement vector

The theory of a laser interference method of determining in real time the relative displacement of two scattering objects in space is put forward and an experimental verification is described. Pis’ma Zh. Tekh. Fiz. 25, 88–94 (December 26, 1999)     

Efficiency of the generation of characteristic radiation by stopping low-energy electron beams

The Monte Carlo method is used to calculate the generation of characteristic radiation by stopping low-energy electrons in converters made of low-Z materials and it is shown that this method of generating characteristic radiation can compete with Z-pinches in terms of conversion efficiency. Pis’ma Zh. Tekh. Fiz. 24, 77–79 (February 26, 1998)     

Investigation of the properties of CuGaTe2 thin films

Thin films of the ternary compound CuGaTe₂ were prepared by pulsed laser-assisted evaporation. Their structure and unit cell parameters were determined by an x-ray method. The transmission spectra near the fundamental absorption edge were used to determine the energies of the interband optical transitions, and the crystal (Δ _cr) and spin-orbit (Δ∞) splittings were calculated. Pis’ma Zh. Tekh. Fiz. 24, 18–23 (February 12, 1998)     

New method for measurement of the concentration of acceptor centers in photorefractive crystals

A new method for measurement of the concentration of deep traps is proposed and confirmed theoretically and experimentally. The method involves measuring the intensities of the signals formed by the first and second harmonics of a holographic grating. Pis’ma Zh. Tekh. Fiz. 24, 56–60 (May 12, 1998)     

Use of a two-wire microwave line at the boundary of the investigated zone to measure the electron density in a low-temperature plasma

A new method based on a two-wire line has been developed for noncontact diagnostics of a low-temperature plasma and its fluxes in channels with complex profiles. This method provides good spatial and time resolution. Pis’ma Zh. Tekh. Fiz. 23, 1–7 (July 26, 1997)     

Laser autodyne interferometry of the dynamic parameters of biological specimens

A method based on the use of autodyne detection effects in a semiconductor laser is proposed to analyze the dynamic state of biological specimens. The advantages of this method compared with conventional photoelectric methods are demonstrated. Results are presented of the use of the proposed method to investigate the heart beat frequency and amplitude of Daphnia as a function of the degree of toxicity of the aqueous medium. Pis’ma Zh. Tekh. Fiz. 24, 39–43 (March 12, 1998)     

Universal nature of the instability of the thermodynamic parameters of transient processes accompanying the melting of crystalline substances in quasistatic regimes

A numerical method of differential thermal analysis was used to study transient processes accompanying the melting of germanium and antimony in quasistatic regimes at heating rates of ∼1 K/min. It is shown that the premelting initiation temperature and the melting initiation point are unstable and depend on the initial conditions. Pis’ma Zh. Tekh. Fiz. 25, 1–5 (February 26, 1999)     

Method of determining the single-domain property of magnetic powder particles

A method of determining the single-domain property of magnetic powder particles based on Mossbauer spectroscopy is proposed and checked experimentally. Pis’ma Zh. Tekh. Fiz. 23, 70–3 (December 26, 1997)     

Reconstruction of the X-ray emission spectrum of a nanosecond creeping discharge

A method is proposed for determining the soft x-ray emission spectrum of a nanosecond creeping discharge. The method includes a determination of the photoelectron density from photocurrent measurements and a calculation of the spectral flux density. The results are compared with experimental data on the wavelength interval of maximum radiation intensity. Pis’ma Zh. Tekh. Fiz. 24, 39–44 (April 12, 1998)     

Mass-spectrometric investigation of the thermal stability of polymethyl methacrylate in the presence of C60 fullerene

The thermal degradation of polymethyl methacrylate, synthesized by the method of free-radical polymerization, in a mixture with C₆₀ fullerene has been investigated by mass-spectrometric thermal analysis. C₆₀ suppresses the first two, low-temperature, stages in the thermal degradation of polymethyl methacrylate and thereby increases its thermal stability. Pis’ma Zh. Tekh. Fiz. 23, 81–85 (September 26, 1997)     

Influence of active oxygen on the superconducting properties of an yttrium ceramic investigated by a diffraction method

A diffractometric method of determining the amount of oxygen in intergranular media is described and the superconducting properties of YBaCuO ceramic are related to the intergranular oxygen content. Pis’ma Zh. Tekh. Fiz. 23, 13–18 (January 12, 1997)     

Modulational method of eliminating the zero shift of a fiber ring interferometer induced by polarization nonreciprocity

A new method is proposed to eliminate the zero shift of a fiber ring interferometer induced by polarization nonreciprocity. This method is based on periodic modulation of the polarization state of nonmonochromatic radiation at the entrance to the interferometer ring system. Numerical estimates are given. Pis’ma Zh. Tekh. Fiz. 25, 78–82 (August 26, 1999)     

A method for the determination of the elastic equilibrium of isotropic bodies with curvilinear inclusions. Part 3. Antiplane deformation

Within the framework of the approach proposed by L. P. Mazurak, L. T. Berezhnyts'kyi, and P. S. Kachur [“Method for determination of elastic equilibrium of isotropic bodies with curvilinear inclusions. Part 1. Mathematical foundations,”Fiz.-Khim. Mekh. Mater.,33, No. 6, 21–31 (1997)], we construct a new method for the determination of elastic equilibrium of cylindrical bodies with noncanonical curvilinear foreign elastic inclusions under conditions of longitudinal shear. Unlike the method of perturbation of the form of a boundary, this method imposes no restrictions on the form of inclusions. The method is based on a procedure of determination of contour integrals of the Cauchy type by using the Faber polynomials. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 35, No. 2, pp. 21–26, March–April, 1999.     

Computer modeling of the migration properties of oxygen in Ba1−x KxBiO3

A molecular statics method is used to calculate the energy barriers for the migration of oxygen ions in BaBiO₃ and Ba_1−x K_xBiO₃ Vacancy and interstitial mechanisms of diffusion are considered. The lowest energy barrier was obtained for the vacancy mechanism. Pis’ma Zh. Tekh. Fiz. 24, 86–88 (February 26, 1998)     

Determination of the uniformity of the carrier lifetime in a material from the profile of the amplitude spectrum of an ion detector

An analysis is made of charge transport in the neutral base of a p ⁺-n structure as a result of its diffusion to the boundary of the p-n junction under conditions where nonequilibrium carriers are generated by single α-particles. It is assumed that nonuniformity of the carrier lifetime (τ), described by a Gaussian distribution, exists over the area of the structure. The profile of the transported charge spectrum is calculated for these conditions and its correlation with the measure of nonuniformity τ is obtained. Since the tracks of the diffusing α-particles occupy an extremely small volume, recording them is equivalent to local probing of the material for τ. It is suggested that the calculated function should be used as a calibration function to determine the spread of τ values in materials. The method is tested on Si for a surface-barrier structure by recording 8.78 MeV π-particles. Pis’ma Zh. Tekh. Fiz. 24, 44–50 (March 12, 1998)     

Diffusion of erbium in silicon

Diffusion of erbium in silicon has been investigated by the electric method. The erbium diffusion coefficient in the temperature range 1150–1250 °C increases from 1.4×10⁻¹³ to 6.2×10^{− 13} cm²·s⁻¹. The values obtained for the diffusion coefficient of erbium in silicon are in good agreement with data obtained by the method of tagged atoms. Pis’ma Zh. Tekh. Fiz. 24, 68–71 (January 26, 1998)     

Evolution of the morphological structure of a two-dimensional cluster obtained with a linear microparticle trajectory in the diffusion-limited aggregation regime

Two-dimensional diffusion-limited aggregation of spherical microparticles was achieved experimentally as a result of their rectilinear motion (“ballistic aggregation”) at a “water-air” interface. A percolation cluster was obtained and the evolution of its morphological parameters was studied under compression. A change in the orientation of the cluster pores and a nonlinear coalescence and breakup process were observed. A fabrication technology is proposed for monolayer films similar to the Langmuir method. Pis’ma Zh. Tekh. Fiz. 25, 80–85 (December 12, 1999)     

InAsSb/InAsSbP heterostructure lasers with a large range of current tuning of the lasing frequency

The lasing spectra and the shift in the position of the modes in the current range (1–5)I _th with various methods of pumping the nonequilibrium charge carriers are analyzed. It is shown that the pumping method does not influence the character of the tuning of the radiation line. The large short-wavelength tuning range (up to 50 Å) is due not to the heating of the crystal lattice in the active-region material but rather the nonuniform nonequilibrium charge-carrier density distribution over the width of the stripe. Pis’ma Zh. Tekh. Fiz. 25, 17–23 (October 12, 1999)