Transverse magnetoresistance peculiarities of thermoelectric Lu-doped Bi2Te3 compound due to strong electrical disorder

The n-type thermoelectric Bi_1.9Lu_0.1Te₃ was prepared by microwave-solvothermal method and spark plasma sintering. The magnetic field and temperature dependences of transverse magnetoresistance measured within temperature 2–200 K interval allow finding the peculiarities characteristic for strongly disordered and inhomogeneous semiconductors. The first peculiarity is due to appearance of linear-in-magnetic field contribution to the total magnetoresistance reflected in a crossover from quadratic magnetoresistance at low magnetic fields to linear magnetoresistance at high magnetic fields. The linear magnetoresistance can result from the Hall resistance picked up from macroscopically distorted current paths due to local variations in stoichiometry of the compound studied. The second peculiarity is that both linear magnetoresistance magnitude and crossover field are functions of carrier mobility which is in agreement with the Parish and Littlewood model developed for disordered and inhomogeneous semiconductors. An increase in the mobility due to a decrease in temperature is accompanied by an increase in the magnetoresistance magnitude and a decrease in the crossover field. Finally, the third peculiarity is related to the remarkable deviation of the total magnetoresistance measured at various temperatures from the Kohler's rule. Presence of strong inhomogeneity and disorder in the Bi_1.9Lu_0.1Te₃ structure concluded from the magnetoresistance peculiarities can be responsible for the remarkable reduction in the total thermal conductivity of this compound.     

Forging furnace with thermochemical waste-heat recuperation by natural gas reforming: Fuel saving and heat balance

This paper considers thermochemical recuperation (TCR) of waste-heat using natural gas reforming by steam and combustion products. Combustion products contain steam (H₂O), carbon dioxide (CO₂), and ballast nitrogen (N₂). Because endothermic chemical reactions take place, methane steam-dry reforming creates new synthetic fuel that contains valuable combustion components: hydrogen (H₂), carbon monoxide (CO), and unreformed methane (CH₄). There are several advantages to performing TCR in the industrial furnaces: high energy efficiency, high regeneration rate (rate of waste-heat recovery), and low emission of greenhouse gases (CO₂, NO_x). As will be shown, the use of TCR is significantly increasing the efficiency of industrial furnaces – it has been observed that TCR is capable of reducing fuel consumption by nearly 25%. Additionally, increased energy efficiency has a beneficial effect on the environment as it leads to a reduction in greenhouse gas emissions.     

On stochastic comparisons of finite mixtures for some semiparametric families of distributions

In this paper, we consider the classical finite mixture model, which is an effective tool for modeling lifetime distributions for random samples from heterogeneous populations. We discuss new results on stochastic comparison for two finite mixtures when each of them is drawn from one of the following semiparametric families, i.e., proportional hazards, accelerated lifetime and proportional reversed hazards.     

Hybridization of acoustic waves in piezoelectric plates

The conditions for hybridization of the zero-order and high-order acoustic waves propagating in a piezoelectric crystal plate have been studied. The dependence of the phase velocity of the hybrid waves on the parameter hf (h is the plate thickness and f is the wave frequency) is established for the potassium niobate and lithium niobate plates possessing various crystallographic orientations and conductivities. It is found that hybridization takes place when the conductivity of a thin surface layer exceeds a certain critical value, which can vary within broad limits depending on the plate material and orientation. The degree of dispersive repulsion of the coupled modes grows with increasing electromechanical coupling coefficient.     

Increasing the corrosion resistance of low-alloy and carbon steels for automobile construction by optimizing the metallurgical technology

It is shown that the corrosion resistance of automobile sheet can be improved by ensuring that steels of this type have a low content of corrosion-active nonmetallic inclusions (CANI). The main mechanisms responsible for the formation of CANI in automobile sheet have been established, and recommendations have been developed to reduce their concentration in this product • optimize the deoxidation processes that are used by ensuring that the proportions of the additions made to the steel are consistent with the composition of the ladle slag and that certain key temperature-time parameters of these processes are maintained • control the composition of the ladle slag to prevent the formation of solid phases in the slag and their transfer to the metal; certain conditions must also be observed in the argon blow and the introduction of the addtions. Use of the above recommendations to make automobile sheet and tube steels cleaner with respect to their content of CANI and thus help optimize out-of-furnace treatments at metallurgical and pipe plants will make it possible to improve the corrosion resistance of metal products used in automotive manufacturing. __________ Translated from Metallurg, No. 2, pp. 45–48, February, 2006.     

Statistical analysis of the amplitudes of random stresses

A study is made of the distribution law for the amplitudes of random stresses and associated parameters. A theoretical law is proposed to describe an empirical distribution, and a comparison is made between the deviations of the endurances corresponding to these laws and the coefficient of variation of random endurance values. An empirical formula is obtained to determine maximum stress amplitudes.Translated from Problemy Prochnosti, No. 3, pp. 63–70, March, 1994.     

DBS电视接收机低中频与直接转换调谐器的比较

CMOS技术是把L波段卫星调谐器、解调器和其它功能整合至低成本、高效能单芯片的关键。本文将探讨新型低中频和传统零中频DBS调谐器架构在单芯片DBS射频前端设计中的优缺点。     

Sequential optimization algorithms for complex extended construction projects

Conclusions Theoretical and practical results indicate that the SAA method can be efficiently applied for the solution of road construction optimization problems with allowance for construction dynamics.We have experimentally established the possibility of replacing the traditional static designs, based only on average initial data, with dynamic designs relying on accurate information about the current conditions. The dynamic designs can be used to develop the best managerial decisions for roadbed construction.Our results again emphasize the need for the development of a qualitatively new scientific-technical base of construction controls relying on integrated application of efficient mathematical methods and computing tools for the analysis and optimal revision of design, technological, and organizational solutions. Our research has led to the development (jointly with Glavbamstroi design office) of a proposal for a program of radical improvement of preparation in the construction industry by establishing an interactive link between CAD systems and MIS. The proposal has been approved by the college of the Ministry of Transportation Construction.This research is merely the first step toward the development of optimization algorithms for an integrated computerized management system for road construction, which should substantially accelerate the search for best design and managerial solutions by allowing sequential optimal revision of earlier alternatives in different stages of the life cycle of the project, strengthening the currently weak feedback from construction to design, and encouraging the experts to assume an active role in on-line search for the best man-machine solutions. Our results to a certain extent have stimulated the organization of design and construction associations, approved by the Resolution of the Central Communist Party of the USSR and the Council of Ministers of the USSR, whose function is to improve the economics of construction and in particular to accelerate large-scale adoption of research results in practice.In addition to the authors, many other researchers took part in this project: V. I. Biletskii (in the development of algorithms and programs and in running the line optimization computations for the longitudinal profile), V. V. Yatskevich (in improvement of programs and in running the earth mass distribution optimization), V. S. Belopol, I. A. Vasilevskii, G. M. Eremeev, E. V. Ivanov, A. P. Kozhevnikov, V. A. Maslov, Yu. B. Narusov, V. S. Plastun, I. S. Rozanov, A. A. Yakubov, V. F. Temnikov, V. A. Shamuratov, V. I. Avdonin, V. A. Baranov, and others (in substantive formulation of the problems, in organization of pilot work, in the analysis of the results, in the development of input data and generalization of the results).Translated from Kibernetika, No. 5, pp. 63–69, September–October, 1988.     

hTERT-Driven Immortalization of RDEB Fibroblast and Keratinocyte Cell Lines Followed by Cre-Mediated Transgene Elimination

The recessive form of dystrophic epidermolysis bullosa (RDEB) is a crippling disease caused by impairments in the junctions of the dermis and the basement membrane of the epidermis. Using ectopic expression of hTERT/hTERT + BMI-1 in primary cells, we developed expansible cultures of RDEB fibroblasts and keratinocytes. We showed that they display the properties of their founders, including morphology, contraction ability and expression of the respective specific markers including reduced secretion of type VII collagen (C7). The immortalized keratinocytes retained normal stratification in 3D skin equivalents. The comparison of secreted protein patterns from immortalized RDEB and healthy keratinocytes revealed the differences in the contents of the extracellular matrix that were earlier observed specifically for RDEB. We demonstrated the possibility to reverse the genotype of immortalized cells to the state closer to the progenitors by the Cre-dependent hTERT switch off. Increased β-galactosidase activity and reduced proliferation of fibroblasts were shown after splitting out of transgenes. We anticipate our cell lines to be tractable models for studying RDEB from the level of single-cell changes to the evaluation of 3D skin equivalents. Our approach permits the creation of standardized and expandable models of RDEB that can be compared with the models based on primary cell cultures.