高效窄带隙共轭聚合物太阳能电池材料设计及器件性能研究进展

窄带隙聚合物材料因能与太阳光谱更好地匹配而备受重视,是聚合物太阳能电池的研究热点。按照窄带隙聚合物给体单元的结构分类,总结了含芴、硅芴、咔唑、环戊二烯并双噻吩、三苯胺和吩噻嗪给体单元的太阳能电池材料的设计以及器件性能,介绍了聚合物的HOMO和LUMO能隙值对其光谱和光电转换效率的影响,并指出了该研究领域目前存在的问题及今后的发展方向。     

新型窄带隙聚合物太阳能电池光伏材料

聚合物太阳能电池中给体材料的能级水平、带隙、光吸收系数、溶解性、成膜性及载流子迁移率是决定器件性能的关键因素.阐述了聚合物太阳能电池中给体材料的最新研究进展,着重介绍了含有苯并双噻吩的窄带隙D-A类型的共聚物,并对一些给体材料的能级水平优化结果做了简单的总结.最后指出了未来聚合物太阳能电池给体材料今后的发展方向.     

有机噻吩类衍生物作为光伏材料的研究进展

聚噻吩及其衍生物是一类重要的有机共轭高分子材料,不仅具有良好的环境稳定性,而且带隙窄,是理想的聚合物光伏材料。分类介绍了有机噻吩类衍生物在聚合物太阳能电池中的研究进展及需要改进的地方,如开路电压、短路电流及能量转换效率仍需要大幅度提高才能应用到生活中。展望了聚合物太阳能电池的发展前景。     

氟材料在有机太阳能电池中的应用

有机太阳能电池具有成本低、质量轻、柔韧性好等优点,提高有机太阳能电池的光电转化率和降低成本,开发新型的有机太阳能电池材料一直是研究的重点。文中简要介绍了有机太阳能电池的特点、工作原理及发展趋势,提出了含氟共轭聚合物在有机太阳能电池给体材料中的研究,重点讨论了含氟苯并噻二唑,含氟苯并三唑及1,5-并噻吩衍生物的研究。同时,讨论了含氟物质在界面修饰材料中的应用。最后,对含氟共轭聚合物在有机太阳能电池未来的发展做出了展望。     

含F有机供-受体聚合物给体材料研究进展

有机受供体聚合物薄膜太阳能电池的活性层是由共轭材料构成。其中含氟聚合物材料因氟原子的存在,有着优异的物理化学性质而被应用到有机太阳能电池的功能材料中,其不仅能提高有机太阳能电池的光电转化效率,还能增强电池的稳定性。目前已报道的基于含F聚合物的光伏器件(organic photovoltaic device,OPV)光电转化效率(power conversion efficiency,PCE)最高已达到12%,应用前景巨大。综述了3类受体单元上含F有机聚合物供体材料近几年的研究进展,并简要分析了F原子的个数以及所在区域位置的不同对器件性能的影响。最后对含氟共轭聚合物在有机太阳能电池未来的发展做出了展望。     

PPV衍生物的合成及其在太阳能电池方面的研究进展

聚合物太阳能电池成为太阳能电池发展的重要方向,本研究针对聚合物太阳能电池材料中颇受关注的聚对苯乙炔(PPV)衍生物,综述了PPV衍生物的合成方法,简要介绍了聚合物太阳能电池的研究现状及存在问题,展望了聚合物太阳能电池的研究方向。     

无机纳米晶/共轭聚合物太阳能电池光敏层制备方法及微观形貌调控

相比硅太阳能电池,无机纳米晶/共轭聚合物太阳能电池因其兼备有机/无机杂化的优点,而近年来一直是国内外广泛关注的热点之一.文中对目前该种太阳能电池光敏层的各种微观形貌、制备方法及研究进展进行了综述.详细介绍了无机纳米晶/共轭聚合物光敏层的三种制备方法,即物理共混法、化学键合式共混法和原位法.同时着重关注了无机纳米晶/共轭...     

有机太阳能电池阴极界面层概述

体相异质结聚合物太阳能电池因具有质轻、柔韧性好、便于大面积印刷等优点引起了越来越多的关注。近年来,聚合物太阳能电池取得了较大的进步。然而,聚合物太阳能电池要实现商业化大面积制备还需要解决一些科学问题,如电荷的分离、传输和收集效率低等。良好的界面接触对提高器件性能至关重要。本文综述了聚合物太阳能电池界面层的作用及分类,包括无机类、富勒烯类、水/醇溶性中性共轭聚合物、水/醇溶性离子型共轭聚合物电解质、超支化小分子和苝酰亚胺衍生物。     

新型三元聚合物给体材料的合成及在有机太阳能电池中的应用

以吡咯并[3,4-c]吡咯二酮(DPP)为A单元,苯并[1,2-b∶4,5-b′]二噻吩(BDT)和萘为D单元,合成了一种新型2D/A型三元共轭聚合物太阳能电池给体材料(PDPP-BDT-NT),通过核磁共振氢谱(1 H NMR)对其结构进行了表征,通过热重分析、紫外-可见吸收光谱(UV-Vis)、循环伏安法对其热学性质、光物理性能及能级结构进行了研究。PDPP-BDT-NT具有较好的热稳定性,热分解的温度为401℃,有较宽的吸收光谱,可覆盖300~900nm,最高占据轨道(HOMO)能级为-5.35eV。以聚合物PDPP-BDT-NT为给体材料,PC60BM为受体材料,制备了一系列有机聚合物太阳能电池,在大气质量(AM)为1.5G,功率为100mW·cm-2模拟的太阳光照射下,有机聚合物太阳能电池的光电转化效率(PCE)可达2.09%。甲醇处理后,有机聚合物太阳能电池的PCE可达2.34%。     

窄带隙聚吡咯甲烷衍生物的制备与光学性能

由于高分子发光材料具有柔韧性好、合成简单、可大面积制备和使用寿命长等优点,成为近年来显示和照明领域的研究热点。本文以N-甲基吡咯和苯甲醛类为单体,采用缩聚法制备了3种可溶性、窄带隙、分子主链为部分共轭的聚吡咯甲烷衍生物,并利用红外光谱、紫外-可见光谱、荧光光谱、X射线衍射谱和热失重分析等方法对其结构、光致发光性质和热稳定性能等进行了测试分析,比较了大分子链上苯环对位取代基对材料发光性能的影响。研究结果表明,3种衍生物的热稳定性较好且具有部分结晶性,其光学禁带宽度均小于1.6 eV,属于窄带隙聚合物;在355 nm左右激发光下,3种衍生物均会产生约420 nm的发射光,为蓝紫色发光材料,且大分子链上苯环的对位取代基对该类材料的发光行为基本没有影响;在循环伏安曲线中,3种衍生物均存在较为明显的氧化还原峰。聚吡咯甲烷衍生物在光电器件材料方面有着潜在的应用价值。     

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.……     

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.     

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.     

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 ...