A study of thick 3C-SiC epitaxial layers grown on 6H-SiC substrates by sublimation epitaxy in vacuum

3C-SiC epitaxial layers with a thickness of up to 100 μm were grown on 6H-SiC hexagonal substrates by sublimation epitaxy in vacuum. The n-type epitaxial layers with the area in the range 0.3–0.5 cm² and uncompensated donor concentration N _d − N _a ∼ (10¹⁷–10¹⁸) cm⁻³ were produced at maximum growth rates of up to 200 μm/h. An X-ray analysis demonstrated that the epitaxial layers are composed of the 3C-SiC polytype, without inclusions of other polytypes. The photoluminescence (PL) spectrum of the layers was found to be dominated by the donor-acceptor (Al-N) recombination band peaked at hv ≈ 2.12 eV. The PL spectrum measured at 6 K was analyzed in detail. It is concluded that the epitaxial layers obtained can serve as substrates for 3C-SiC-based electronic devices. Original Russian Text ? A.A. Lebedev, V.V. Zelenin, P.L. Abramov, E.V. Bogdanova, S.P. Lebedev, D.K. Nel’son, B.S. Razbirin, M.P. Shcheglov, A.S. Tregubova, M. Suvajarvi, R. Yakimova, 2007, published in Fizika i Tekhnika Poluprovodnikov, 2007, Vol. 41, No. 3, pp. 273–275.     

The metastability of low-pressure water in turbulent flow

Results are given of an experimental investigation of superheating of water at low pressures of 32–170 kPa, which rises up the thrust adiabatic region (d = 0.05 m, H ≈ 20 m) of circulation loop at a velocity of 0.05–0.42 m/s (Re = ((9?72) × 10³). The values of maximal superheating of water relative to the saturation temperature in the cross section being treated are determined, as well as their dependences on the parameters of water flow. Based on the experimental results, closing relations are suggested.     

Nonlinear Delay of Excitation of Oscillations of a Magnetostriction Transducer in the Frequency Multiplication Mode

Journal of Communications Technology and Electronics - The problem of excitation of nonlinear forced oscillations of magnetization and elastic displacement in a ferrite plate of a magnetostriction...     

Allowing for hysteresis in the calculation of fields in the elements of accelerator magnetic systems

Iron magnetic circuit residual magnetization may contribute as much as several Gs to the magnetic field in charged-particle accelerators. This contribution depends on the magnetization “history.” It is not taken into account in most of the existing software that uses the main magnetization curve. Therefore, an error in field calculations usually exceeds 1%, which is unacceptable for accelerators. In this article, a simple phenomenological magnetic-hysteresis model that is suitable for numerical computations is suggested. Approximations based on the proposed model are compared to the results of measurements on partial hysteresis cycles in a steel ring.     

A vector model of wave propagation through an interface of dissipative media

The possibility of solution of the problem of wave propagation through an interface of two dissipative media with the help of a trigonometric vector model is shown. Two invariants independent of the dissipation of these media are revealed: (i) the sum of projections of vectors of reflected and transmitted waves onto the polar axis, which is equal to the projection of the vector of the incident wave onto the same axis, and (ii) the sum of projections of vectors of these waves onto the normal to the polar axis, which is equal to zero.     

Studying the Thermal and Hydraulic Characteristics of a Shell-and-Tube Water Heater Equipped with Dimpled Heat-Transfer Tubes to Enhance Heat Transfer

Results of a thermal-hydraulic investigation of a steam-water heater equipped with dimpled heat-transfer tubes are presented. It is shown that heat transfer on the internal dimpled surface has risen by 60% with their drag increased by a factor of 2.1.     

Effects of a central hole in a fuel tablet on the thermophysical characteristics of VVER fuel rods

Reactors Institute and Kurchatov Institute, Russian Scientific Center. Translated from Atomnaya énergiya, Vol. 80, No. 4, pp. 306–308, April, 1996.     

On the possibility of acoustic probing of gas wells

The possibility of probing the critical areas of gas wells using acoustic signals is analyzed. The results of investigations on the evolution of acoustic waves in cylindrical channels with permeable portions surrounded by a porous space are presented. The quantitative and qualitative features of the dynamics of waves as a function of the state of an inhomogeneous porous medium are established. Results showing that the state of the reservoir characteristics of rocks has a substantial influence on the evolution of acoustic signals are obtained. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 4, pp. 118–126, July–August, 2007.