染料敏化太阳电池石墨/聚苯胺复合对电极的低温制备和性能

通过低温制备(120℃)构建出不同比例石墨/聚苯胺复合对电极,分析了复合对电极组装的染料敏化太阳电池(DSCs)的光电性能,并通过X射线衍射仪、傅里叶红外光谱仪、电化学交流阻抗法和循环伏安法等表征方法探讨了光电性能变化的内在原因,同时探讨了复合对电极中引入镍纳米颗粒对DSCs光电性能的影响。结果表明:在对电极中,聚苯胺质量含量25%的复合对电极对I_3~-/I~-氧化还原反应具有更佳的催化活性,其DSCs短路电流密度、开路电压分别达到7.41mA·cm~(-2),和0.595V,其DSCs光电转换效率最大为2.193%,与纯石墨对电极和纯聚苯胺对电极时相比,光电转换效率分别提高了86.6%和45.3%。添加镍纳米颗粒后,导致复合对电极串联电阻的增加以及催化活性的弱化,最终促使相应器件的四个光电性能参数均有不同程度的下降。     

低温制备介孔碳对电极构建的染料敏化太阳电池优化研究

以高比表面积的介孔碳为催化层材料通过低温烧结构建出对电极, 着重优化了其组装的染料敏化太阳电池(DSC)的整体结构和性能. 结果表明: 在碳浆料中添加Triton X100能改善碳颗粒之间以及碳催化层与衬底之间的接触界面, 促使DSC的转换效率从4.50%提升到4.82%, 增幅为7.1%. 随TiO₂薄膜厚度增加, DSC的转换效率先急剧增加, 随后趋于缓和, 其变化趋势是染料吸附量与电子传输路径相互竞争的结果. 在电解质中添加磷酸三丁酯能减小电解质电阻, 促使DSC的转换效率从3.59%提升到4.42%, 增幅为23.1%. 优化后, 介孔碳对电极DSC的转换效率达到4.82%.     

低温制备石墨/活性碳对电极的光电性能及阻抗分析

通过低温制备(120℃)出不同活性碳/石墨比例的碳对电极,着重分析了碳对电极的阻抗特征及其染料敏化太阳电池(DSCs)的光电性能,同时探讨了碳对电极中引入银导电浆料对DSCs光电性能的影响.结果表明,DSCs的光电性能随着碳对电极中活性碳含量的增加而增强,其中短路电流和转换效率与活性碳含量呈线性关系,而填充因子与活性碳含量呈抛物线变化.阻抗分析发现,电荷转移阻抗(RCT)和Nernst扩散阻抗(Zp)随着碳对电极中活性碳含量的增加而减小.碳对电极中活性碳含量越低,加入银导电浆料对DSCs光电性能的改善越显著,当为纯石墨对电极时,DSCs的转换效率提高了13.6％.     

基于二维SEM图像的介孔碳表面分形特征分析

将分形理论引入到介孔碳孔结构表征,基于SEM图像计算二维分形维数(D2)及三维分形维数(D3),并分析了分形维数与孔结构参数之间的规律.结果表明,D2及D3能有效地量化介孔碳形貌的差异,两者随形貌的变化一致,即D2越大D3也越大.当介孔碳的显气孔率相近时,平均孔径越小D2和D3越大,反映出介孔碳具有越多的细部特征和越粗糙的表面.     

染料敏化太阳电池多级孔炭对电极的制备及性能研究

以F127为模板剂, 采用自组装与后活化相结合制备了具有微孔-介孔结构的多级孔炭. N2吸附等温线分析表明后活化可在介孔炭孔壁上生成大量微孔. 电化学阻抗谱测量表明多级孔炭电极对I₃^-还原反应的催化活性明显高于介孔炭电极, 电荷迁跃电阻为0.3 Ω·cm². 多级孔炭电极催化活性高是由于它具有较高的比表面和特殊的多级孔结构, 有效比表面积较高. 以多级孔炭电极为对电极组装染料敏化太阳电池, 电池的短路电流密度、开路电压和填充因子分别为0.624V、15.44 mA/cm²和0.67, 相应的光电转换效率为6.48%, 比介孔炭对电极电池的光电转换效率提高了11.5%.     

钼酸锌-碳复合材料在染料敏化太阳能电池对电极中的应用

采用水热合成法制备出片状结构钼酸锌, 并以其为原料, 添加石墨(G)或导电碳(Cc), 利用喷涂法分别制备出ZnMoO₄、ZnMoO₄-G和ZnMoO₄-Cc对电极催化材料, 应用于染料敏化太阳能电池(DSCs)中。实验结果表明: 以ZnMoO₄为对电极材料的DSC光电转换效率为4.19%, 在分别添加石墨及导电碳制备成复合对电极材料后, 其相应的光电转换效率分别提高到6.56%及7.36%。其中, ZnMoO₄-Cc对电极与相同条件下铂对电极的光电转换效率(7.81%)相当。电化学阻抗(EIS), 循环伏安法(CV)及Tafel极化曲线测试结果表明, ZnMoO₄、ZnMoO₄-G和ZnMoO₄-Cc三种材料均具有一定的导电性和电催化性能。     

1,3,5-三甲苯扩孔改性硼掺杂有序介孔炭

以F108为模板剂,1,3,5-三甲苯(TMB)为有机扩孔剂,采用溶剂挥发诱导自组装的方法成功制备出了具有较大孔径、比表面积和有序性高的硼掺杂有序介孔炭。探究了扩孔剂用量对硼掺杂介孔炭结构的影响,并对其电化学性能和扩孔机理进行了分析。结果表明,当扩孔剂与模板剂的用量比为1.5时,所得的介孔炭TMB-1.5的孔径最大(4.2nm),比表面积最高(666m~2/g)。相对于未扩孔改性的介孔炭,孔径和比表面积分别提高了5%和10%。扩孔改性后的硼掺杂介孔炭具有良好的电化学性能,在0.2A/g电流密度下的比电容高达235F/g。     

有序介孔炭合成、改性及其对汞离子的吸附性能

以有序介孔硅基材料(SBA-15)为模板,内烯酸低聚物为前驱物合成有序介孔结构的炭材料(OMC),并以化学方法将含氮基官能闭嫁接在有序介孔炭的表面.利用扫描电子显微镜(SEM),透射电子显微镜(TEM),红外光谱(FT-IR),X射线衍射(XRD)和氮气吸附-脱附(BET)对介孔炭进行表征.结果表明:表面改性后有序介孔炭的结构发生一定变化,但孔道特征仍保持二维六方有序性.合成的有序介孔炭及经乙二胺表而改性后胺化有序介孔炭的比表而积、平均介孔直径、平均孔容积分别为607 m2/g,4.1 nm,0.62 cm3/g和558 m2/g,3.8 nm,0.58cm3/g.对有序介孔炭及改性有序介孔炭进行的汞吸附实验,发现表面改性前后有序介孔炭对Hg(II)的吸附性能发生显著变化.嫁接胺基功能团后,其吸附容量增加一倍,表明胺基改性的OMC对汞有亲和作用.     

简易合成不同孔径尺寸的半石墨化有序介孔炭

以SBA-15介孔硅为模板,硼酸为扩孔剂,调控合成出不同孔径尺寸的半石墨化有序介孔炭.采用X射线衍射仪(XRD)、氮气吸附、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、热重(TG),以及拉曼(Raman)光谱等手段对样品的成分、结构和形貌进行了分析.结果表明:通过合成过程添加硼酸的方法可以实现对介孔炭材料的孔径在3nm～7nm范围内精确调控,而且合成的介孔炭材料具有半石墨化的墙壁结构.该方法简单易行,对介孔炭材料的孔结构调控合成具有很好的应用价值.     

双面吸光透明碳对电极染料敏化电池的光电性能

以聚乙二醇800(PEG800)为碳源,采用原位形成技术在导电基底上原位形成一体式透明碳催化层,着重考察了配液时碳源的溶剂类型以及旋涂速率对碳对电极透光率、形貌、催化活性及其组装的染料敏化太阳电池(DSCs)双面光电性能的影响。结果表明,不同工艺下获得的碳对电极均具有较优异的透光性,在可见光范围内(400~700nm)的透光率基本达到了70%以上。在考察的2种溶剂中,乙酰丙酮和异丙醇混合液比乙酰丙酮和丙酮混合液更适合作为PEG800的溶剂,相同旋涂速率下能获得透光率更高、催化活性更佳的碳对电极,相应的器件具有更佳的正面转换效率和反面转换效率。旋涂速率和碳对电极的催化活性以及相应器件的正反面转换效率之间均呈反比关系。表面粗糙度不同是引起碳对电极性能各异的主要原因。此外,碳对电极DSCs的反面转换效率/正面转换效率的比值高于80%,大于Pt对电极器件的44%。     

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.……     

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.     

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...     

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 ...