Test Experiences with the DaimlerChrysler Fuel Cell Electric Vehicle NECAR 4

The DaimlerChrysler fuel cell electric vehicle NECAR 4, a hydrogen‐fueled zero‐emission compact car based on the A‐Class of Mercedes‐Benz, is described. Test results obtained on the road and on the dynamometer are presented. These and other results show the high technological maturity, reliability and durability already achieved with fuel cell technology.     

Phenomenological Theory of Solid Oxide Fuel Cell Anode

We develop a phenomenological theory of oxygen‐ion‐conducting porous cermet anode for solid oxide fuel cells utilizing hydrogen, based on a simple picture of macro‐ and microkinetics of charge and gas transport in the cermet. Its basic equations account for the transport of hydrogen molecules and oxygen anions to the reaction spots, the hydrogen oxidation reaction (whose various mechanisms, including different adsorption stages, are considered) and the water‐product removal. Simple analytical results are obtained for a linear current‐voltage regime, which demonstrate the interplay of these three processes. The nonlinear behavior is analyzed and classified. Various mechanisms of reaction kinetics are considered, subject to three possible mechanisms of water adsorption, in order to specify the law of conversion of ionic current into electronic one. Revealed is the nature of the intermediate quasi‐Tafel regime, in which the anode is usually employed, and of two possible large current regimes: the saturation regime and the blocking regime (due to oxidation of the anode). The study rationalizes principles of anode functioning and builds a basis for a systematic analysis of the effects due to composite structure, that enter through the basic parameters of the theory.     

Electroactive Mesoporous Yttria Stabilized Zirconia Containing Platinum or Nickel Oxide Nanoclusters: A New Class of Solid Oxide Fuel Cell Electrode Materials

The electroactivity of surfactant‐templated mesoporous yttria stabilized zirconia, containing nanoclusters of platinum or nickel oxide, is explored by alternating current (AC) complex impedance spectroscopy. The observed oxygen ion and mixed oxygen ion–electron charge‐transport behavior for these materials, compared to the sintered‐densified non‐porous crystalline versions, is ascribed to the unique integration of mesoporosity and nanocrystallinity within the binary and ternary solid solution microstructure. These attributes inspire interest in this new class of materials as candidates for the development of improved performance solid oxide fuel cell electrodes.     

大气等离子喷涂固体氧化物燃料电池用低温阴极材料

大气等离子喷涂由于能够快速制备具有可控微结构的功能涂层,在固体氧化物燃料电池(SOFCs)制造中具有广阔的应用前景。该技术使得低温运行(500～700℃)的SOFCs可通过在耐用低成本金属支撑体上直接喷涂得以制备。不过,目前商业应用的SOFCs所使用的标准阴极材料在较低运行温度下具有很高的极化电阻,因此,开发可替代的高性能低温阴极材料是推动金属支撑体应用的关键。在不锈钢基材上通过轴向注入大气等离子喷涂方法制备了镧锶钴铁氧化物(LSCF)涂层,并对涂层的厚度和微观结构进行了表征,同时采用X射线衍射(XRD)方法分析了等离子喷涂过程中涂层材料的分解和杂质相的产生。根据这些结果确定了能够制备LSCF涂层的等离子喷涂参数,以及可用于喷涂复合阴极涂层的条件范围。     

p53基因状态对人卵巢癌细胞辐射敏感性的影响

本研究应用PCR-SSCP银染法检测3株人卵巢癌细胞p53基因的存在状态,以四甲基偶唑蓝（MTT）染色法和流式细胞术（FCM）比较不同p53基因状态的肿瘤细胞在1～10Gy^60Coγ射线照射后的体外生长及凋亡率。结果显示,p53野生型的A2780细胞^60Coγ射线照射后发生明显的生长抑制和凋亡,而p53基因突变型的A2780-CP细胞和缺失型的SKOV3细胞则呈现较强的辐射抗性。本研究结果说明,人卵巢癌细胞的p53基因状态直接影响其对γ射线照射的敏感性。     

一种细胞分割新方法

为了解决传统的细胞彩色图像分割中遇到的诸多问题,采用了一种新颖的多光谱成像技术进行图像采集,并探索性地将支持向量机用于骨髓细胞图像的分割。实验证明这种以多光谱技术为基础的分割方法推广性好,准确率非常高,并且对采集设备状况和涂片质量依赖性低。     

辐射致人正常肝细胞蛋白质组电泳图谱的改变

利用蛋白质组学技术对0.5和2Gyγ射线照射后4小时人正常肝细胞的蛋白质的变化进行了初步探讨。研究结果表明:与对照组相比,0.5Gy处理组中,照射后4h差异蛋白点数为146个,其中表达上调的蛋白67个,表达下调的蛋白79个;2Gy处理组中,照射后4h差异蛋白点数为127个,其中表达上调的蛋白83个,表达下调的蛋白44个。0.5Gy和2Gy处理组共同差异表达的蛋白点数56个,其中,表达上调的39个,表达下调的17个。肽质量指纹图谱分析结果显示共同表达的差异蛋白有热休克蛋白、胞内氯离子通道蛋白以及核磷蛋白等。     

原代大鼠肾小球系膜细胞最佳电转染条件的探索和验证

目的探索并验证原代大鼠肾小球系膜细胞最佳电转染条件。方法设立不同的电压与电容组合、电击前孵育温度、质粒DNA浓度等电转染条件,将绿色荧光蛋白表达质粒pEGFP-C1导入原代大鼠肾小球系膜细胞。24h后比较各组细胞存活率和绿色荧光蛋白表达情况,确立最佳电转染条件。再以此条件电转染质粒pcDNA3.1和pcDNA3.1-FHL2,48h后收取两组细胞RNA和蛋白。应用RT-PCR和Western印迹检测目的基因FHL2的核酸和蛋白表达,验证电转染效果。结果在电击前室温孵育,40μg质粒,340V电压、550μF电容的最佳电转染条件下,原代大鼠肾小球系膜细胞的电转染效率可达40%以上,细胞存活率在50%左右。转染FHL2质粒组较对照组检测FHL2的核酸和蛋白表达水平明显升高(P<0.05)。结论适当的电转染条件可以有效转染原代大鼠肾小球系膜细胞。     

太阳电池的效率分析

随着太阳能利用的日益广泛，光电转换将越来越受到人们的关注。光电转换效率就是其中的一个热门话题。众所周知，不是任何一种半导体材料都可做出高效率的太阳电池，不同的材料，能带结构一般不相同，因此对太阳光谱的吸收也不相同。文章着重讨论能带结构对光生载流子跃迁的影响、能带结构与光生载流子寿命和迁移率的关系、缺陷对能带结构的影响，并提出提高太阳电池效率的对策。     

60Co γ射线照射对k562细胞周期变化的影响

以不同剂量的60Co γ射线照射人红白血病细胞系k562细胞,用流式细胞仪检测照射后24小时及不同时间点的细胞周期变化.照后24小时检测结果表明,随着照射剂量的增加,G2/M期细胞比率增加,剂量达15 Gy时,出现明显的G2/M期阻滞;随着剂量的进一步增加,S期细胞比率逐渐增加,剂量达30 Gy时出现明显的S期阻滞;在此剂量(5～30 Gy)下,细胞凋亡未见明显变化.不同时间点的检测结果表明,随着照射剂量的增加,k562细胞从以G2/M期阻滞为主逐渐转化为以S期阻滞为主,同时细胞凋亡也明显增加.