双面正交条纹透镜理论分析

双面正交条纹透镜的聚光倍数较高，光斑均匀，光线经它两次折射后能到达任意指定的方向。对该透镜进行了理论分析。     

对菲涅耳透镜的工艺改进--塑料透射式太阳能聚光器

180多年前，数学家菲涅耳将平凸透镜拉平．制成了由系列小棱镜构成的平板薄片透镜，这就是著名的“菲涅耳透镜”（见图1）。由于薄而轻，用材少，已在多学科、多领域得到应用，如眼科用薄片透镜、齿科照明灯、灯塔、教学仪器、太阳灶等等。菲涅耳透镜的缺点在于：其一，由于棱镜二面全部为平面，焦点为聚焦斑（如图2甲），聚集比远不如球面透镜高（如图2乙）；     

软质PVC塑料平板Fresnel圆透镜设计与制造

本文报道了软质PVC塑料平板Fresnel圆透镜的设计和制造,对影响透镜光学效率的各种因素作了分析,并讨论了提高光学效率的措施。     

高倍太阳能聚能透镜的研究与产业化

研究了基于三结型(InGaP/InGaAs/Ge)高效太阳电池组合的高倍聚光太阳能透镜,采用高次非球面光学玻璃的聚能透镜组成卡塞格林系统,实现200～500倍的聚光太阳能。提出采用热压成型的方法生产高倍太阳能聚光器件(副镜),并实现了产品的产业化。阐述了产品的技术标准、生产工艺流程、研制的专用设备。最后提供了热压成型高倍聚光太阳能聚能透镜(副镜)产品的照片及非球面透镜面形的测试结果。     

专利信息

本发明为一种太阳能热水器。它由光采集器、热吸收器、水管道、储水器等组成。光采集器至少包括一个条形菲涅尔聚焦透镜，用来提高提高太阳能热水器的光源能量密度，将太阳光聚焦在热吸收器上。条形菲涅尔透镜为一组相互基本平行的三棱透镜，三棱透镜组构成一个平面组合。     

太阳能等照度带聚焦菲涅耳透镜研究

为了提高聚光发电时太阳电池的光电转换效率,从提高太阳电池表面会聚光强分布的均匀性入手,对传统平板型线聚焦透镜进行改进,提出一种用于聚光光伏发电的等照度带聚焦菲涅耳透镜设计方法。带聚焦菲涅耳透镜分为奇数个单元,每个单元宽度与太阳电池宽度相等,单元内所有尖劈角φ相等并将太阳辐射等宽度折射至太阳电池表面,从而实现各单元透过的太阳能等照度叠加。最大聚光比由光伏电池宽度、透镜与太阳电池间距以及透镜材料折射率决定。对带聚焦和线聚焦两种透镜聚光条件下电池表面温度分布情况进行比较分析,验证了等照度带聚焦透镜设计的可行性。     

风透镜优化构型对垂直轴风力机气动性能研究

风透镜是一种应用于垂直轴风力机的新型外部辅助装置,为探究风透镜结构对垂直轴风力机气动性能的影响,通过数值模拟的方法,结合贝塞尔曲线对其构型进行优化设计。结果表明：风透镜具有较好的聚风性能,有助于垂直轴风力机气动性能的提升,风透镜结构参数中扩散器半开角对风力机气动性能影响较大,法兰次之。风透镜优化构型后可进一步提升垂直轴风力机的风能利用系数和力矩系数,风能利用系数最高可达参考垂直轴风力机的8.60倍,并使垂直轴风力机在更大叶尖速比工况下仍保持较高运行效率,进一步提升其有效运行工况范围。     

基于菲涅尔透镜聚光的遮阳伞温差发电系统

为了使太阳能可以得到更加充分的利用,设计了一种应用在大型遮阳伞上的半导体温差发电系统。本设计运用半导体材料的塞贝克效应,利用半导体温差发电片进行发电,通过菲涅尔透镜的聚光作用来为半导体温差发电片的热端加热,采用水冷的方式为其冷端散热,并用蓄电池储存半导体温差发电片所产生的电能。通过实验,得到了菲涅尔透镜与温差发电片的相对布置距离以及冷却水流速对温差发电片输出功率的影响。     

LED路灯自由曲面二次光学透镜的设计

半导体发光二极管（LED）的发光效率高、寿命长等优点,使其成为目前道路照明中的应用趋势。针对LED在道路照明上的应用,为获得路面上均匀的矩形配光效果对选定的LED进行自由曲面二次光学透镜的设计,设计出符合城市道路照明标准的LED路灯配光方案,使LED模组直接实现矩形配光。考虑封装后LED的实际配光曲线应用网格对应法利用计算软件标定自由曲面二次光学透镜的离散数据点坐标,对透镜结构进行建模。     

利用正演模型研究塔里木卡拉沙依组砂岩储层

在地震正演中,利用塔里木卡拉沙依组实际资料建立不同的砂岩透镜体模型,得出各种地震响应。对比不同的结果,从而了解在该区地震波的分辨能力和能够识别最小砂岩厚度的能力,认为这对砂岩储层预测有现实的指导意义。     

PHOTOVOLTAIC CELLS AND MODULES: TECHNICAL AND ECONOMIC OUTLOOK TOWARDS THE YEAR 2000

There is a clear need for renewable energy and PV is a very attractive renewable energy source. The paper describes the different requirements for photovoltaic materials and compares these materials on the basis of these requirements. Silicon in general and crystalline silicon in particular fullfil the largest part of the current PV-market and the technological issues of this materials are therefore described in more detail from source(feedstock) material, over crystallization and wafering up to cell and module fabrication. The potentiality to serve the market and the ecological impact are extremely large and encouraging. Industrial capacity is increasing. Some applications are economic already now at current prices, but the large electrical market penetration can only come if conversion efficiencies are increased and cost is reduced further by accelerating the increase in production volumes and R&D efforts considerably.     

Radiation-resistant solar cells for space use

This paper reviews the present status of radiation-resistant solar cells made with Si, GaAs, InP and InGaP/GaAs for space use. At first, properties of radiation-induced defects in semiconductor materials and solar cells are described based on an anomalous degradation of Si space solar cells under high-energy, high-fluence electron and proton irradiations. Advantages of direct bandgap materials as radiation-resistant space cells are presented. Unique properties of InP as radiation-resistant cells have also been found. A world-record efficiency of 26.9% (AM0) has been obtained for an InGaP/GaAs tandem solar cell. Radiation-resistance of the InGaP/GaAs tandem cells is described.     

TRANSPARENT INSULATION MATERIALS AND THEIR APPLICATION IN ACTIVE AND PASSIVE SYSTEMS

Transparent or translucent insulation materials (TIM) represent a new class of materials with a high potential for increasing the efficiency of solar thermal systems. A large number of materials and material combinations has been subjected to theoretical and experimental investigation. An overview of generic types, characterisation methods, real existing materials available on the market, and the future potential of transparently insulated systems will be given as well as first results of applications in active and passive systems.     

Evolution of space solar cells

The solar cells used in space for over 40 years are reviewed by discussing the semiconductor materials which have provided the best cells. Most emphasis was on high efficiency, combined with good tolerance to charged particle bombardment, and the steady increase in efficiency is discussed. The most important requirement is that the cells must be highly reliable, consistent in performance, and stable while operating in space. The need for highest reliability makes the costs less important. The progress to date has provided a good foundation for future applications for space cells.     

Modelling and simulation of elements for solar heating and daylighting

Through the development of highly efficient transparent insulation materials (TIM), new opportunities are appearing in the field of daylighting and passive solar space heating. The simulation program WANDSIM, developed at the Fraunhofer-Institut für Solare Energiesysteme (ISE), models the dynamic performance of three important elements for daylighting and passive solar space heating: window glazing; transparently insulated masonry; transparently insulated glass wall. Selected simulation results of each type are represented and compared under thermal and daylighting aspects. The advantages of the transparently insulated glass wall, a new combined passive space heating and daylighting system, in economy and comfort are verified.     

洞室爆破开采堆石坝料的新探索

黄石滩面板堆石坝料采用洞室爆破法开采,用“小抵抗线、条形药包、大间距、单药包起爆”的设计方案,结合生产进行了试验研究,开采的石料级配连续,爆堆平缓,周围民房安全无恙,达到了爆破设计目的。     

UNIQUENESS AND CONTINUOUS DATA DEPENDENCE TN DYNAMICAL PROBLEMS OF NONLINEAR THERMOELASTICITY

Abstract

This paper is concerned with the dynamical problems of nonlinear thermoelasticity. Uniqueness and continuous dependence results are established for smooth admissible thermodynamic processes residing in the region of slate space where the internal energy is a convex function and the elastic material behaves as a definite conductor of heat. When the initial-displacement boundary-value problems are considered, the uniqueness and continuous dependence are established again under the weaker assumption that the thermodynamic processes reside in the strong ellipticity region in state space.     

Recent developments in thermoelectric materials

The increased activity in attempts to develop improved thermoelectric semiconductors for use in the direct conversion of heat into electrical energy results mostly from research sponsorship by the US Military and NASA. Thermoelectric generators have no moving parts and are difficult to detect by visual, aural or thermal infrared means. Fossil multifuelled thermoelectric generators are the leading candidates for replacing standard US Military engine generator sets up to 1·5 kW under the SLEEP programme (Signature Suppressed Lightweight Electric Energy Plants). When coupled to an isotopic heat source, thermoelectric generators are able to operate reliably and unattended for long periods of time and have a proven performance record in supplying electrical power to the Lunar Experimental Package (Apollo Program) and in providing onboard electrical power to the Voyager spacecrafts.In both military and space applications any improvement in the thermoelectric generators' conversion efficiency would result in a saving in fuel—an important consideration. One way of improving the conversion efficiency is by increasing the so called ‘Figure of merit’ of the semiconductor material employed in the fabrication of the generators' thermocouples. In this paper an assessment is made of current thermoelectric materials; recent attempts to improve the figure of merit of existing materials are discussed and a number of new thermoelectric materials described.Significant headway has been made in reducing the lattice thermal conductivity of thermoelectric materials through the use of additives, small grain sizes or combinations of both. This development will result in substantial improvements in the thermoelectric figure of merit, provided the electrical properties can be maintained close to single crystal values. It is concluded that, because in the past the development of new thermoelectric materials has occupied long periods of time, even during periods of intense research activity, it is likely that established or ‘modified’ established materials will remain the mainstay of military and space applications at least for the forseeable future.     

NUMERICAL SOLUTIONS OF THERMOELASTIC WAVE PROBLEMS BY THE METHOD OF CHARACTERISTICS

This article is concerned with the numerical treatment of thermal and thermal stress waves in thermoelastic solids. To keep the numerical treatment general, the development of the formulation is based on the generalized theory of thermoelasticity. A number of thermoelastic wave problems, which involve one or two space variables, are treated, in a uniform manner, by a system of first-order partial differential equations with stress, velocity, heat flow, and temperature as dependent variables. This system of equations is analyzed by the method of characteristics, yielding the characteristics and the characteristic equations. Procedures of numerical integration along the characteristics are established and carried out for several generalized and classical thermoelastic wave problems in homogeneous materials, composite materials, nonhomogeneous materials, and nonlinear elastic solids.     

MACROSCALE AND MICROSCALE THERMAL TRANSPORT AND THERMO-MECHANICAL INTERACTIONS: SOME NOTEWORTHY PERSPECTIVES

Some noteworthy and historical perspectives and an overview of macroscale and microscale heat transport behavior in materials and structures are presented. The topic of heat waves is also discussed. The significance of constitutive models for both macroscale and microscale heat conduction are described in conjunction with generalizations drawn concerning the physical relevance and the role of relaxation and retardation times emanating from the Jeffreys type heat flux constitutive model, with consequences to the Cattaneo heat flux model and subsequently to the Fourier heat flux model. Both macroscopic model formulations for applications to macroscopic heat conduction problems and two-step models for use in specialized applications to account for microscale heat transport mechanisms are overviewed with emphasis on the proposition of a Generalized Two-Step relaxation / retardation time-based heating model. So as to bring forth a variety of issues in a single forum, illustrative numerical applications are overviewed including some relevance to thermo-mechanical interactions