Fe-Cr合金连接体NiMn_2O_4涂层的制备及性能研究

Fe-Cr铁素体合金是中低温固体氧化物燃料电池理想的连接体材料,但其在高温下缺乏良好的抗氧化性能,影响了电池的高效安全运行。采用传统溶胶-凝胶提拉技术在预氧化处理Fe-Cr合金连接体表面制备NiMn_2O_4保护涂层,并系统研究了涂层对合金连接体高温微观组织结构、抗氧化性能及导电性能的影响规律。研究结果表明,溶胶-凝胶提拉法能够在预氧化处理Fe-Cr合金连接体表面制备出均匀致密,与基体结合良好的NiMn_2O_4保护涂层。经800℃空气中168h高温氧化,涂覆NiMn_2O_4涂层后合金连接体的高温氧化速率仅为涂覆前的1/3,且涂覆涂层后合金连接体较涂覆前具有较低的长时间稳定的面比电阻(10mΩ·cm~2)。     

SOFC合金连接体材料的研究进展

对固体氧化物燃料电池(SOFC)用合金连接体材料的研究进展进行了介绍,分别对镍基、铬基和铁基合金合金连接体材料的研究发展情况给予评述,对每种连接体材料的特点和存在的问题进行了详细的论述,并指明了各种合金连接体材料的今后发展趋势.最后着重指出铁基合金及其表面改性是今后连接体材料发展的主要方向.     

固体氧化物燃料电池铁素体不锈钢连接体的导电/保护涂层

铁素体不锈钢因具有诸多优点而成为中温固体氧化物燃料电池(SOFC)连接体部件的标准材料。根据SOFC的运行环境,综述了连接体在电池堆中所起的作用、性能要求和材料种类。针对用作SOFC铁素体不锈钢连接体的活性元素氧化物型、稀土钙钛矿型、尖晶石型和MAlCrYO型4类导电/保护涂层材料,重点论述了其作用机理、主要制备技术及研究进展。     

固体氧化物燃料电池新型连接体材料的研究进展

连接体是固体氧化物燃料电池(SOFC)中的关键组件，对连接体的高性能需求一直制约着SOFC的商业化发展。随着SOFC的运行温度降低到800℃以下，廉价的高温抗氧化金属连接体材料取代掺杂铬酸镧(LaCrO₃)陶瓷的可能性大大增加。此外，为了优化连接体的性能，大量的导电/保护性涂层及新的复合材料也不断地涌现。综述了迄今为止连接体材料的发展现状，在对各种连接体材料以及涂层材料的性能和优缺点进行比较的同时，重点介绍了新开发连接体材料的研究进展，并对连接体材料的发展趋势进行了展望。     

钙钛矿型中低温固体氧化物燃料电池阴极材料研究进展

中低温固体氧化物燃料电池的研制是固体氧化物燃料电池商业化的必然趋势,阴极材料的研制是影响其发展的关键问题之一.本文综述了近年来固体氧化物燃料电池ABO3型钙钛矿阴极材料的研究情况,并提出了其发展方向.     

LaCrO3基陶瓷材料在SOFC中的研究进展

综述了LaCrO3材料在固体氧化物燃料电池(SOFC)中作为陶瓷连接材料、合金连接体的涂层材料以及新型阳极材料的国内外最新研究进展.介绍了LaCrO3作为陶瓷连接材料的使用要求,在热膨胀性能、烧结性能、电性能和化学稳定性能等方面的研究情况,并介绍了磁控溅射、等离子喷涂、溶胶-凝胶(Sol-gel)工艺等几种LaCrO3涂层材料制备方法以及LaCrO3作为新型阳极材料的催化性能、导电性能和热膨胀性能等方面的研究进展,对其发展前景进行了展望.     

导电(Cu,Mn)3O4接触层在SOEC阳极侧的应用

固体氧化物电解池(SOEC)中铁素体不锈钢合金连接体和电解池阳极之间存在界面接触、连接体表面氧化以及氧电极“铬毒化”等问题,是导致电解堆性能衰减的重要影响因素之一。本工作利用反应烧结工艺在连接体与阳极之间制备了多孔的(Cu, Mn)₃O₄导电接触层,形成了粘结强度高的连接体/接触层/电解池界面结构。所得试样在750℃下表现出优异的电性能,整个500 h测试过程半电池的面比电阻(ASR)值稳定保持在20.13～20.32 mΩ·cm²。通过微观结构表征技术证实,多孔(Cu, Mn)₃O₄接触层与相邻的电解堆部件具有良好的兼容性,并可以抑制连接体表面的氧化薄膜增长,同时阻止铬元素的迁移。(Cu, Mn)₃O₄接触层也降低了电解池与集流体之间的接触电阻,提高了电池电化学输出性能。     

中低温固体氧化物燃料电池的研究

中低温固体氧化物资料电池（ＳＯＦＣ）是燃料电池研究的一个重要方向，综述了研究开发中低温ＳＯＦＣ的途径及现状，并指出了应解决的几个问题。     

W、Mo添加对Fe-21Cr合金连接板高温性能的影响

Fe-Cr合金是固体氧化物燃料电池(SOF-Cs)连接板材料的最佳候选之一,但仍存在氧化速率较快以及热膨胀系数(TEC)较大等问题。采用热胀系数小的W和Mo元素,研究了W或Mo对Fe-21Cr合金热膨胀系数、面电阻及抗氧化特性的影响。研究结果表明,适量W或Mo的添加可以降低Fe-21Cr合金的热膨胀系数,并提高其750℃高温抗氧化性能。     

面向金属-空气电池和中低温固体氧化物燃料电池应用的钴基电催化剂综述

在21世纪的今天,由石油、煤炭等化石资源的过度开发与使用所引发的能源和环境问题日趋严重,开发经济、高效的能源转换与存储装置已成为新时代的研究主题。金属-空气电池和中低温固体氧化物燃料电池,作为高效的能源转换与存储装置,可以实现化学能向电能的高效转换,具有效率高、环境友好、成本低的显著优点,在过去十几年内受到了研究者的广泛关注,取得了惊人的成果。但与此同时,人们在研究中发现阴极(正极)缓慢的氧还原和氧析出反应速率极大地降低了电池转换效率,增加了应用成本,在很大程度上制约了金属-空气电池和中低温固体氧化物燃料电池的商业化发展和应用。钴基催化剂作为一种高效阴极材料,相比贵金属成本较低,且具有混合离子-电子导电性,可以有效降低极化电阻,对阴极氧还原和氧析出反应显示出高催化活性,近年来吸引了国内外学者极大的研究兴趣。对于金属-空气电池,虽然钴基催化剂如钴氧化物、尖晶石型氧化物、钙钛矿型氧化物等材料能够显著地提高金属-空气电池的电容量和循环性能,并且降低充电电压,有效降低极化,但是其催化活性和稳定性有待提高,催化机理和活性位点也需要进一步明确和探究;对于中低温固体氧化物燃料电池,钴基催化剂包括La_(1-x)Sr_xCoO_3-δ、La_(1-x)Sr_xCo_(1-y)FeyO_3-δ、Ba_(1-x)Sr_xCo_yFe_(1-y)O_3-δ和钴基双钙钛矿等材料可以大大降低阴极极化电阻和面积比电阻,提高功率密度,但是相对其他催化剂,热膨胀系数普遍较高,稳定性也较差。为了进一步提高钴基催化剂应用在金属-空气电池和中低温固体氧化物燃料电池中的催化活性,研究者采用了掺杂其他金属元素、与其他物质组成复合阴极材料以及贵金属修饰等方法,在很大程度上提高了这两种电池的性能。本文简要介绍了金属-空气电池和中低温固体氧化物燃料电池的结构、工作原理,并在此基础上着重评述了近年来面向这两种能源转换与存储器件的,包括钴氧化物、钙钛矿型氧化物、尖晶石型氧化物和双钙钛矿氧化物等在内的各种钴基电催化剂的制取、改性和性能研究探索与成果。     

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.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.     

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.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.