Economical technology for cryoproduct storage and delivery

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 11, pp. 22–23, November, 1992.     

Self-reinforced materials based on aluminum nitride

Powder Metallurgy and Metal Ceramics -     

Three-dimensional inverse scattering of a dielectric target embedded in a lossy half-space

A modified iterative Born method is applied for three-dimensional inversion of a lossless dielectric target embedded in a lossy half-space. The forward solver employs a modified form of the extended Born method, and the half-space Green's function is computed efficiently via the complex-image technique. Example results are shown, with all scattering data based on a computational model, utilizing a rigorous forward solver distinct from that employed in the inversion. In addition, distinct gridding schemes are used in the forward and inverse solvers. Simple Tikhonov regularization is found to yield adequate results for inversion of noisy data.     

Exciton photoluminescence in doped quasi-1D structures based on silicon

The dependence of carrier density in silicon quantum wires sheathed with SiO₂ on the wire diameter and the position of impurity atoms in respect to the wire center is analyzed theoretically. It is shown that, as the diameter of wires and nanocrystals decreases, the ionization energy of a dopant increases; therefore, the free carrier density decreases, and the screening of the Coulomb attraction becomes ineffective. As a result, the photoluminescence is defined by the radiative recombination of excitons even in the case of heavily doped Si. These conclusions are supported by the data of experimental study of spectral, excitation-power, and temperature dependences of photoluminescence in porous silicon structures fabricated on lightly and heavily doped Si substrates.     

Specifics of initial steam condensation and its influence on corrosion damage in turbines

Processes of corrosion cracking of the metal of turbine blades in the region of initial steam condensation are considered. Possible ways of preventing corrosion-fatigue damage to the blades are proposed.     

CFD Simulation of Liquid Film Flow on Inclined Plates

A two‐phase flow CFD model using the volume of fluid (VOF) method is presented for predicting the hydrodynamics of falling film flow on inclined plates, corresponding to the surface texture of structured packing. Using the proposed CFD model the influence of the solid surface microstructure, liquid properties and gas flow rate on the flow behavior was investigated. From the simulated results it was shown that under the condition of no gas flow the liquid flow patterns are dependent on the microstructure of the plates, and proper microstructuring of the solid surface will improve the formation of a continuous liquid film. It was also found that liquid properties, especially surface tension, play an important role in determining the thin‐film pattern. However, there are very different liquid film patterns under the action of gas flow. Thinner liquid films break easily, but thicker liquid films can remain continuous even at higher gas flow rates, which demonstrates that all factors affecting the liquid film thickness will affect the liquid film patterns under conditions of counter‐current two‐phase flow.     

十年磨一剑——记上海上大玲珀化工科技有限公司董事长朱勇强

穿着朴实，谈吐文雅，举止端庄，从他富有表情的脸上和那对炯炯有神的眼睛，折射出一个青年科技企业家特有的自信、干练、豁达与刚毅。他，就是上海上大玲珀化工科技有限公司的董事长朱勇强博士。在与他寒喧之际，记者感到朱博士是位思维敏捷、善于开拓、好学求进、富有创新精神和管理才能的既懂技术、又会经营的复合型人才。他谈吐中潜在的智慧、才干和创业的理念使记者佩服。