Bi2Te3热电材料研究现状

Bi2Te3热电材料是半导体材料,室温下具有良好的热电特性,能够实现热能和电能的相互转化,应用前景十分广阔。Bi2Te3热电材料的转换效率低是影响其应用的瓶颈之一,目前世界范围内的研究热点主要集中在如何提高热电材料的能量转换效率上。综述了热电材料的种类、国内外关于Bi2Te3热电薄膜的制备方法和性能研究,对多种典型制备方法进行分析对比,探讨了影响Bi2Te3热电薄膜质量的因素及机制。结合Bi2Te3热电薄膜在温差发电和热电制冷方面的应用,如果微型热电制冷器实现与大功率LED芯片集成封装,那么芯片级低温散热问题有望解决。     

Zintl结构化学在热电材料研究中的应用

Zintl相化合物满足“电子晶体-声子玻璃”特征,能够通过化学掺杂和结构修饰来提高其热电性能,是理想的热电材料研究对象。阐明了热电材料性能优化的Zintl结构化学原理,介绍了Zintl结构化学在高性能热电材料研究中的应用,指出利用Zintl结构化学原理寻找高性能热电材料是今后热电材料研究的重要方向。     

基于光束偏转层析技术的三种Radon变换迭代法

本文通过计算机模拟研究,利用气体温度场的先验知识,考查了用光束偏转层析技术重建三维温度场的基于卷积反投影的三种Radon变换迭代法。作为一种应用实例,测试了某截面上的气体温度分布,并与热电侧测量的值进行了比较。     

计算机网络技术在企业中的应用

近年来,计算机网络技术作为一项公共技术在我国的各行各业中应用较为普遍,通过计算机网络技术的应用可以通过高效、迅速、时效等方面来简化人力劳动。在我国的各大企业中,计算机网络技术虽然应用较为普遍,但是也存在着一些问题,本文将对我国当前计算机网络技术在企业中的应用现状及问题,希望可以推动计算机网络技术在企业中的应用和发展。     

浅谈计算机在企业管理中的应用

首先分析了计算机在企业管理中所发挥的作用,其次剖析了当前计算机在企业管理应用中存在的问题,在此基础上提出了提高计算机在企业管理中应用效率的具体措施。     

关于企业职工计算机培训的思考

计算机应用技术的不断发展,计算机在企业管理中的作用正逐步被人们所认识,企业职工培训也因此有了新的内容。本文从计算机应用的重要性出发,在分析企业职工培训现状的基础上结合企业的实际情况,提出了计算机应用在企业职工培训中的应用策略。     

电子元器件热电冷却技术研究进展

在深刻分析热电制冷机理的基础上,结合国内外学者对热电制冷技术用于电子元器件热管理的理论分析,从芯片整体表面散热和局部热点消除两方面,详细介绍了集成电路芯片热电冷却实验的国内外研究进展;对芯片热电冷却技术的数值模拟与热电制冷器(TEC)的选型优化进行了详细报道;指出国内缺乏芯片热电冷却的应用研究,在芯片散热的整体研究水平上与国外仍有差距.芯片热电冷却及其表面的热管理将是今后提高电子元器件散热性能的一个重要研究方向.     

热电冷却器的有限元热分析

针对热电冷却器在电子设备散热中的应用,参照冷却器的材料属性和工艺结构,在有限元软件中构建其3D模型,并根据冷却器实际工作环境加载参数,得到热电冷却器的稳态电压云分布和温度场分布图;根据仿真的热特性结果,分析热电冷却器在电子散热应用中的工作情况,并为电子设备散热中热电冷却器的结构设计和改进提供理论参考,不仅可以降低设计的成本,还能大大减少研究的时间周期.     

微型热电能量采集器的研究进展

热电能量采集器是一种基于塞贝克效应,利用温差将热能直接转化成电能的温差发电装置.由于其体积小、重量轻、寿命长、无机械运动部件、绿色环保等优点,微型热电能量采集器(MTEG)已经引起了国内外的广泛关注.综述了微型热电能量采集器在国内外的研究进展,介绍了温差发电的工作原理,从热电材料和器件结构两方面重点探讨了微型热电能量采集器的研究现状.对微型热电能量采集器未来的发展方向进行了分析和预测,认为积极寻找具有高优值系数的热电材料制备易于加工和集成的高性能的微型热电能量采集器是未来研究工作的目标.微型热电能量采集器有广阔的应用前景.     

有关计算机网络技术在企业信息化过程应用的分析

近年来,计算机网络技术实现了飞速发展,技术的成熟使其应用领域越来越广,给生产生活带来了极大的便利。企业信息量大,促进其信息化已成为一种必然的趋势,这样才能不断优化企业管理,在市场竞争中占据优势地位。因此,有必要对计算机网络技术在企业信息化过程应用进行深入分析,不断完善企业内部建设。本文将从计算机网络技术和企业信息化的相关概念、计算机网络技术在企业信息化中的应用方式、计算机网络技术在企业信息化应用中存在的问题、企业信息化工作中网络问题应对策略等方面详细阐述。     

Combined Parameter and Tolerance Design for Quality via Computer Experiment: A Design for Thermoelectric Microactuator

A thermoelectric microactuator is examined with a computer experimental approach based on the asymmetrical thermal expansion of the microstructure with two beams of different widths. Because a typical U-shaped lateral thermoelectric actuator is used, the remaining concerns are the associated parameters and tolerance values that need to be determined. Conventional approaches consider that parameter and tolerance variables are two unconnected controllable variables, with the condition that the analytical functions representing the design of interest are known. A belief that the two variables are unconnected, usually fails to find truly optimal solutions, particularly a belief that the design functions are nonlinear in a complicated design. Assuming that design functions are normally known is a mistake in most cases, especially in the early stage of design. In this regard, a simultaneous parameter and tolerance design accompanying the computer experiment is developed to ensure that true optimization is achieved. The computer experimental approach consists of both a computer simulation and a statistical method. In this paper, the computer simulation is performed with existing computer-aided engineering (CAE) software, and ANSYS, the finite-element method for the solution of coupled 3-D mechanical problems. The statistical method is one of a design experimental approach such as response surface methodology (RSM). The response value is the conformation rate used in measuring product quality for uncertain conditions. This approach provides designers not only with optimal parameter and tolerance values, but also with the importance ranking for the controllable variables of a product. This is particularly important for the evolutionary design processes in an uncertain environment.      

On Improvement of the Accuracy and Speed in the Process of Measuring Characteristics of Thermoelectric Materials

Results are presented on creation of novel methods for reduction of errors in measured properties of thermoelectric materials obtained by using object-oriented computer simulation for study of real physical models of the absolute method. The effects of radiation, heat losses along the electrodes, design elements of the measurement setup, non-dot-matrix of probes and sensors, and imperfection of thermal and electric contacts have been determined. Methods of eliminating errors due to these effects have been developed. Automated measuring equipment for complex study of thermoelectric material properties has been created, offering accuracy in thermoelectric figure of merit determination several times higher than conventional analogs. Values of errors obtained during measurements of Bi-Te-based materials within the temperature range from 30°C to 500°C include ～0.5% for electrical conductivity, ～0.7% for thermoelectromotive force, ～3% for thermal conductivity, and ～4.7% for figure of merit (Z). The dynamic processes of achieving steady-state measurement conditions and possible errors due to deviations from these conditions are investigated. Functions of current through the sample, reference heater, and radiation shield heater are determined, whereby measurement speed is increased, which is of particular importance for investigation of large-size samples, such as parts of thermoelectric material ingots.     

Test System for Thermoelectric Modules and Materials

We present a design for a complex measuring device that enables its user to assess the parameters of power-generating thermoelectric modules (TEMs) (or bulk thermoelectric materials) under a wide range of temperatures (T _cold = 25°C to 90°C, T _hot < 450°C) and mechanical loading (P = 0 N to 10⁴ N). The proposed instrument is able to monitor the temperature and electrical output of the TEM, the actual heat flow through the module, and its mechanical load, which can be varied during the measurement. Key components of our testing setup are (i) a measuring chamber where the TEM/material is compressed between thermally shielded heating blocks equipped with a mechanical loading system and water-cooled copper-based cooler, (ii) an electrical load system, (iii) a type K thermocouple array connected to a data acquisition computer, and (iv) a thermostatic water-based cooling system with electronically controlled flow rate and temperature of cooling water. Our testing setup represents a useful tool able to assess, e.g., the thermoelectric parameters of newly developed TEMs and materials or to evaluate the thermoelectric parameters of commercially available modules and materials for comparison with values declared by the manufacturer.     

Self-Contained Thermoelectric Generator for Cell Phones

Results of research and development of a 1 W thermoelectric generator for cell phones are presented. A physical model of the generator with catalytic combustion of gas fuel is proposed. A computer simulation method is used to determine the optimal parameters of the thermopile, catalytic heat source, and microgenerator heat rejection system whereby the efficiency of gas combustion heat conversion into electrical energy is a factor of two higher compared with existing analogs. The generator design is described, and results of experimental research on its parameters and the charging rate of cell phone batteries with capacity of 900 mA h to 1600 mA h are given. In the self-contained operating mode of various low-power devices, the elaborated thermoelectric generator with a catalytic heat source is an alternative to traditional sources of chemical energy.     

分散控制系统在热电厂自动控制上的应用

分散控制系统(DCS)是计算机技术和自动化技术相结合发展的结果.本文结合新沪热电厂新建三炉两机采用分散控制系统(DCS)实现自动控制的工程实践,介绍DCS系统特点和功能,并根据DCS系统的运行情况,结合实际维护进行简单阐述.     

热电材料的研究进展

随着热电材料与薄膜制备技术和性能研究手段的发展,具有高热电性能的热电薄膜和低维结构受到人们关注。目前,国内外研究主要集中在如何提高热电材料的能量转换率等核心技术问题上。介绍了热电材料的理论背景、材料分类、制备手段和热电性质的表征,其中,制备手段及热电性质表征主要以Bi2Te3基热电材料展开论述。最后,对热电材料的发展和未来研究方向进行总结。     

Control Strategy for a 42-V Waste-Heat Thermoelectric Vehicle

A 42-V waste-heat thermoelectric vehicle is employed as a potential application of thermoelectric generators for fuel economy improvement and emissions reduction. The 42-V waste-heat thermoelectric vehicle currently in development employs an assemblage driving system consisting of a waste-heat thermoelectric generator, a 42-V powernet, and an integrated starter and generator (ISG). The waste-heat thermoelectric generator also functions as a power supply. To optimize the utilization of the waste-heat energy generated by the thermoelectric generator, an electric assist control strategy and a torque split control strategy are proposed herein. Through the development of relevant systems and strategies, including the thermoelectric generator and an electric bus system, two vehicle models are established and compared using the ADVISOR platform based on MATLAB/Simulink. The calculation results show improved fuel economy and emissions performance resulting from the integration of the torque split control strategy into the 42-V waste-heat thermoelectric vehicle.     

The Law of Thermoelectric Induction and Extending the Capabilities of Its Application

Fundamental consideration of the law of thermoelectric induction is presented. The concept of similarity between the law of thermoelectric induction in electricity and Faraday’s law in electrical engineering is considered. Theoretical foundations for the use of the law of thermoelectric induction are discussed. Computer methods for the discovery of new thermoelement types different from thermocouples are described. New types of thermoelectric power converters are considered, and their advantages over thermocouples are demonstrated. Further progress in thermoelectricity due to the use of the law of thermoelectric induction is predicted.     

Symmetry Analysis of Thermoelectric Energy Converters with Inhomogeneous Legs

Symmetry analysis has been applied to thermoelectric energy converters [thermoelectric generators (TEG), coolers (TEC), and heaters (TEH)] with inhomogeneous legs. The features of the crystallographic symmetry of thermoelectric materials and the symmetry of legs, thermocouples, and modules are studied. The effect of symmetry on the figure of merit Z of thermoelectric energy converters is considered. A general rule for proper placement of legs in thermoelectric converters is developed. A modified tetratomic classification for thermoelectric energy converters with inhomogeneous legs (TEG^a, TEG^b, TEC, and TEH) is proposed. An increase in Z for thermoelectric energy converters with inhomogeneous legs is due to the bulk thermoelectric effect. An increase in Z gives the reduction of irreversible processes in the modules (Joule heating and thermal conductivity), accompanying breaking of the symmetry of the legs. It is found that violations of the symmetry requirements can lead to significant energy losses in converters.