气门用4Cr9Si2钢调质工艺研究

采用正交试验 ,研究了 4Cr9Si2钢的淬火温度、回火温度与组织、硬度间的关系 ,得出了最佳的工艺参数 (10 10℃淬火 ,6 0 0℃回火 )。实际生产表明 ,采用此工艺后 ,断裂现象基本消除 ,气门的热处理质量有了明显提高。     

轻型轨道车下道装置手压泵结构参数的优化设计

本对影响轻型轨道车下道装置操作性能的液压系统参数进行了分析，对２９．４ｋＷ走行发电轻型轨道画下道装置中的手动液压泵的结构参数进行了优化设计，与初定参数进行了比较，并对方案设计进行了修正。     

Viscous behaviour of glass-forming liquids: a thermodynamic approach

The temperature dependence of the viscosity of the undercooled melts exhibits an important role in the study of nucleation, crystal growth and the glass-forming ability of materials. Several attempts have been made to study the viscous behaviour of the glass-forming melts and these investigations are mainly based on free volume theory as well as on the configurational entropy model. In the present investigation, an attempt has been made to correlate the thermodynamic parameters with the viscosity of the glass-forming melts and to study the temperature dependence of the viscosity of undercooled liquids on the basis of the free volume theory as well as on the basis of the configurational entropy model of Adam and Gibbs. The entire study is confined on the expression for thermodynamic parameters reported by the authors recently. The expression obtained has been successfully applied to study the temperature dependence of the viscosity of the metallic, molecular and oxide glass-forming liquids.     

Measurement of metal nanolayers optical parameters using surface plasmon resonance method

The results of experimental definition of optical parameters of silver nanolayers by the method of surface plasmon resonance (SPR) are described. The goniometric installation for measurement of angular dependences of reflection of light by layered nanosructures at the attenuated internal reflection (angular spectrum of reflection) is designed. Calculation of optical parameters of nanolayers is executed taking into account the form of a curve of tin angular spectrum of reflection. The text was submitted by the authors in English.     

Development of a suitable model for characterizing photovoltaic arrays with shaded solar cells

The aim of this study is to investigate the effects of non-uniform solar irradiation distribution on energy output of different interconnected configurations in photovoltaic (PV) arrays. In order to find which configuration is less susceptible to mismatch effects, a PV module model is developed. This model can take into consideration the effects of bypass diodes and the variation of the equivalent circuit parameters with respect to operating conditions. The proposed model can provide sufficient degree of precision as well as solar cell-based analysis in analyzing large scale PV arrays without increasing the computational effort. In order to produce more reliable and robust simulations, improved and extended algorithms are presented. Some results are discussed in detail and some recommendations are extracted by testing several shading scenarios.     

A study of the static and dynamic properties of side-chain liquid crystalline polymers in low molar mass mesogens

The static and dynamic properties of solutions of a side chain polysiloxane liquid crystal polymer have been studied in a cyanobiphenyl nematic host as a function of concentration and temperature. Refractive index measurements were carried out on aligned samples and the data used to determine the macroscopic order parameter, S, using Haller's method. Photon correlation spectroscopy has been used to measure ($\text{k}{}_{22}\text{γ}{}_1$) for the pure nematic solvent and the solutions. From these measurements it appears that the static properties vary slowly and linearly with increasing polymer concentration whilst the dynamic or viscoelastic properties change markedly. This change has been attributed to γ₁, the twist viscosity, and the results have been discussed in terms of the function of the siloxane polymer backbone.     

搜索三个不同坏硬币的测试次数

§1.简介 设S={c_1,c_2,…,c_n}是由n个外观相同的硬币组成的集合,其中恰有m个稍重的坏硬币,试用最少的测试次数找出这m个坏硬币.以μ_m(n)表示最少测试次数,由信息论可知     

Analytical investigations of transitional operating modes of the second circuit of units at NPP with water-moderated reactors with consideration of control systems

A mathematical model for analysis of process parameters of equipment in the second circuit of nuclear power plants is presented, and the structure of the program and principles used for analysis of the equipment are described. A mathematical model for analysis of the deaerator and steam generator is described in detail. A computational analysis of several transitional modes, which is made possible on the basis of the mathematical model in question, is also presented in this paper, and a comparison is made with test data. __________ Translated from élektricheskie Stantsii, No. 3, March 2007, pp. 16–22.     

超薄带精密轧机辊形调节计算机控制

介绍一种超薄带精密轧机的计算机控制系统改造。超薄带精密轧机用于轧制０．０１ｍｍ～０．５ｍｍ的超薄带材，其辊形调节系统是影响带材板形的关键部分。原系统响应慢，可靠性差，难以满足精轧要求。现对该轧机进行改造，采用计算机，将ＰＣＭ（ＰｕｌｓｅｃｏｄｅＭｏｄｕｌａｔｉｏｎ－脉冲码调制）控制与二次型性能指标最优化控制相结合的控制方法用于轧机的的全面管理与控制，不仅大大提高系统精度与运行可靠性，而且实现调整与控制自动化。目前已投入正常运行。     

折反光学系统最佳红外像面位置的研究

较深入地研究了折反光学系统的红外像面,为确定实际的红外像面提出了一个新方法—计算从可见光边缘无色的弥散圆到红外最佳像面的距离。实践证明,这是确定这类光学系统最佳像面的一个方便、可靠的方法。