偶氮类光电导材料研究进展

简述偶氮类光电导材料的发展历史，分类及其机理的研究。讨论了以分子内、分子间电荷转移的概念来确定有机光电导材料中光电子运动的本质，对于光导体的发展趋势也作了分析和展望。     

晶体硅太阳能电池少子寿命测试方法

少数载流子寿命(简称少子寿命)是半导体晶体硅材料的一项重要参数,它对半导体器件的性能、晶体硅太阳能电池的光电转换效率都有重要的影响。分别介绍了常用的测量晶体硅和晶体硅太阳电池少子寿命的各种方法,包括微波光电导衰减法(MW-PCD),准稳态光电导方法(QSSPC),表面光电压(SPV),IR浓度载流子浓度成像(CDI),调制自由载流子吸收(MFCA)和光束(电子束)诱导电流(LBIC,EBLC),并指出了各种方法的优点和不足。     

酞菁类化合物有机光电导材料的成膜方式

为制备较高光电导性的酞菁有机复合膜，本文简要分析了影响其光电导性的主要因素，针对酞菁类化合物难溶性和成膜困难，对这类有机光电导材料的成膜方式进行了概述，着重探讨了分散于聚合物成膜材料中涂覆成膜、LB膜，蒸发镀膜及悬挂酞菁环衍生物的可溶性聚合物成膜等工艺过程中遇到的某些关键性技术问题，并提出了对这类光电导材料进一步研究的部分建议。     

聚酰亚胺及其LB膜光电导性研究进展

对芳香性聚酰亚胺及其Ｌａｎｇｍｕｉｒ－Ｂｌｏｄｇｅｔｔ膜的光电导性研究作了总结,讨论了分子链结构、取向、掺杂等因素对其光电导性的笔电荷转移络合物的光电导机理。结果表明,给电子基团的引入有利于分子链间电荷转移络合物的形成,从而提高其光敏性;大分子链的堆积和高度有序的排列、取向,有利于光生载流子的定向全和光电导性能的提高。     

基于光导开关脉冲偏置电压的太赫兹时域光谱系统

利用光导开关产生脉冲偏置电压的方式改进了基于光电导天线的太赫兹时域光谱系统.在分析光电导天线产生THz波原理的基础上,重点研究了目前基于光电导天线的太赫兹时域光谱系统存在的问题,探讨了解决斩波器引起的机械噪声和光电导天线脉冲偏置电压之间矛盾的途径.最后,通过对光导开关的特性测试,提出了利用高压直流电源、光导开关和纳秒激...     

膜层厚度对CuPc/ZnS多层复合薄膜光电性能的影响

为了找到制备CuPc ZnS多层复合膜薄膜最佳光电导性能的参数 ,本文研究了CuPc ZnS多层复合膜的CuPc膜层的厚度系列、ZnS膜层的厚度系列的光电导性能和结构 ,利用表面电位衰减仪、紫外 -可见光谱仪和X射线衍射仪等设备分析了复合薄膜的光电导性能和结构及其关系 ,探讨了改变CuPc、ZnS膜层的厚度对CuPc ZnS多层复合膜薄膜的光电导性能和结构的影响     

膜层厚度对CuPc／ZnS多层复合薄膜光电性能的影响

为了找到制备CuPc/ZnS多层复合膜薄膜最佳光电导性能的参数,本文研究了CuPc/ZnS多层复合膜的CuPc膜层的厚度系列、ZnS膜层的厚度系列的光电导性能和结构,利用表面电位衰减仪、紫外－可见光谱仪和X射线衍射仪等设备分析了复合薄膜的光电导性能和结构及其关系,探讨了改变CuPc、ZnS膜层的厚度对CuPc/ZnS多层复合膜薄膜的光电导性能和结构的影响。     

硫化铋微米花的制备及其光响应性能

采用混合溶剂热合成法成功制备直径为4μm的Bi_2S_3微米花。研究不同反应时间和溶剂比对产物形貌的影响。另外,以玻璃为基底,利用Bi_2S_3微米花和ITO电极,通过简单滴涂的方法组装了一种光电导结构的可见光探测原型器件。光电性能测试表明,其在模拟太阳光下的光电流为暗电流的50倍,响应时间和衰减时间分别为227ms和880ms,具有优异的光电响应性;通过周期性的开关测试器件,光电流没有明显衰减,表明该器件具有良好的稳定性。     

用于微波真空电子器件的光电阴极

为了满足高频率、小型化真空微波器件的需求,寻找合适的阴极材料和激光系统,开展了用于微波真空电子器件的光阴极研究,提出了一体化的光电阴极制备方法,通过加热具有扩散阻挡层的发射物质存储室,提供受控的光电发射层,以代替活性物质蒸发损失,从而延长阴极的使用寿命,并可以从中毒、暴露大气过程中恢复。在超高真空系统内制备了Cs3Sb光电阴极,利用连续激光器测得其量子效率为0.145%(0.53μm),在能量为0.37W的连续激光照射下,测得发射电流密度达29.2m A/cm2。光电阴极在高强度的激光作用下被损坏后,重新加热激活,光电发射可以得到一定的恢复并长时间稳定,说明这种光电阴极具有可重复激活的特点,有望成为微波真空电子器件的理想电子源。     

光电导聚苯胺／染料共聚材料性能的研究

以直接耐墨染料,均苯四酸酐及聚苯胺为原料,通过缩聚反应获得感应染料／聚苯胺嵌段共聚的光电导聚苯胺分子结构,该聚合物具有优良的溶解性能和成膜能力,电导率达到１０＾－１Ｓ／ｃｍ。元素分析该聚合物的Ｎ：Ｓ摩尔比理论值与实测值相吻合,红外谱图证实了所合成产物的结构,紫外吸收分析表明用直接耐墨Ｇ与聚苯胺段共聚后在可见光区,近红外区具有较强的吸收,大幅度提高了其光电导性能,热失重研究表明聚苯胺用直接耐墨Ｇ嵌得     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...