具有红外反射膜的节能白炽灯

目前流行的节能卤钨灯产品是基于用溶胶-凝胶技术涂TiO2/SiO2多层干涉红外反射膜.给出红外反射膜的厚度对近红外波段的反射分布以及涂层对2850K照明光源在可见光范围内的影响,讨论灯丝和泡壳的几何形状,以及钨丝对红外反射能量的吸收;同时列出实验结果.     

底金属表面预处理对静电粉末涂复层性能的影响

前言 静电粉末涂层和电泳涂漆层一样,要求在被涂金属表面预处理一层磷化膜,以提高涂层的附着力和抗蚀性能。有人也许会认为,静电粉末涂层比较厚,甚至达100多微米,比电泳涂漆涂层厚得多,涂层的抗蚀性能定会很好,故可省去底金属磷化处理工艺。但事实上,静电粉末涂层对表面预处理的要求比一般的涂漆还要严格些。因为它不象一般油漆会把工件表面少量油污物质溶解和吸附,所以,工件表面的预处理对静电粉末涂层的性能有很大关系。为了比较不同表面预处理方法对粉末涂层的影响,我们进行了各种配套样品的人工试验。现将试验情况分述如下。     

固体聚合物电解质水电解池电极的优化研究

目前固体聚合物电解质(SPE)水电解池的膜电极催化层中各组分的配比普遍以全氟磺酸树脂(Nafion)与催化剂的质量百分比来表征,但是由于催化剂的堆密度不同,对于不同的催化剂如果沿用相同的质量配比会造成催化层中Nafion含量的失调,影响电极的质子与电子传导能力。研究了以Nafion与催化剂的体积比来表征电极催化层的组分配比和结构,并利用交流阻抗、循环伏安、极化曲线等电化学测试方法,对其体积比进行了最优化研究。结果表明,Nafion与阳极催化剂(Pt黑与IrO2混合物)的体积比1∶10时水电解的性能最佳。     

采用湿壁塔氨吸收法去除烟气中SO2的实验研究

为检验并流降膜湿法烟气脱硫装置效果,以氨水作为吸收剂,对模拟烟气脱硫进行实验研究.考察吸收液pH值、液气比、烟气中SO2体积质量以及进气温度对脱硫率的影响.实验结果表明:随着吸收液的pH值,液气比以及吸收液浓度增大,脱硫率增大;随着烟气中SO2体积质最增大,脱硫率下降;烟气温度对脱硫率影响不大.实验得到最佳工艺参数为:在进气浓度为2500mg/m3时,液气比为2.4～2.8L/m3,吸收液pH值为5.8～6.5.在最佳工艺参数下脱硫效率可以达到95%.本实验研究可以为氨法脱硫的工业化应用提供有益的参考.     

PEMFC膜电极结构优化的中国发明专利技术进展

检索了质子交换膜燃料电池(PEMFC)膜电极在中国的发明专利文献,综述了膜电极结构优化包括非对称设计、附加功能层、催化剂涂层膜和有序化等方面的专利技术进展,并对发展前景进行了展望。     

PEMFC金属双极板金涂层原电池腐蚀机理研究

为了追求低接触电阻和高耐腐蚀性能,金涂层虽然成本高昂但是仍然在金属双极板涂层中得到广泛应用。通过镀金涂层金属双极板在3 000 h电堆实际测试分析了金涂层的电化学腐蚀情况,同时采用电化学加速测试分析了其原电池腐蚀机理。研究结果表明,金属双极板金层在寿命测试过程中首先因为点蚀而出现轻微缺陷,钛层裸露到质子交换膜燃料电池(PEMFC)的酸性环境中而与金层形成原电池腐蚀。本研究将有助于提出缓解金涂层腐蚀失效的方案,为镀金涂层金属双极板在PEMFC上的应用提供理论指导。     

硅钢自粘结涂层的常规性能研究

基于常规热固型自粘结涂料性状,讨论其涂布作业性和涂层产品的基本性能,研究了涂层厚度、一次烘干和二次固化过程中的工艺参数对涂层主要性能的影响。结果发现:一定范围的涂料性状(黏度、固含等)能获得较好的涂层表观和膜厚均匀性,进而对产品性能起到积极效果;控制膜厚为3~5μm,并选用合适的一次烘干和二次固化工艺参数,能获得最优的涂层综合性能;该类热固性自粘结涂层产品的绝缘性和粘结性能分别满足180℃和150℃的长期服役工况。     

电晕放电烟气净化设备防腐涂层导电特性研究

开发电晕放电烟气净化设备用防腐导电涂料,对涂层的导电特性进行了研究。涂层导电机理为渗流、隧道效应和场致发射综合作用。涂层比电阻随填料粒度的增大、添加量的增加显著下降,温度对比电阻影响不大,涂料的比电阻为102～104Ω.cm量级。极板涂覆涂层后,直流电晕放电电流略有下降,脉冲电晕放电波形不变,涂层不影响电晕放电烟气净化效果,该涂料用于电晕放电烟气净化设备的防腐是可行的。     

聚苯胺改性钢在模拟PEMFC环境下的电化学行为

利用电化学方法沉积纳米导电聚苯胺膜对质子交换膜燃料电池(PEMFC)用薄层金属双极板改性,并对改性双极板在模拟PEMFC阳极环境下的电化学性能进行了测试.结果表明,纳米聚苯胺膜层能使1Cr18Ni9Ti不锈钢在模拟腐蚀液中的腐蚀电位由-350mV提高到250mV.在模拟阳极操作电位下,经10h恒电位极化没有观察到膜层的降解和脱落.纳米导电聚苯胺膜层能显著提高不锈钢在模拟电池环境下的耐蚀性而不影响其导电性,进一步提高导电聚合物涂层性能和评价其长期效果还需进行深入的研究.     

美国聚合物电池的研究与开发

阐述了聚合物电解质中离子迁移的基本概念、固体电解质膜 (SEI)层以及纯聚合物电解质的组成 ;新型的正极和负极材料 ,如低成本的磷酸铁和锂锡合金体系在显著提高电池性能方面很有潜力。聚合物体系新的封装概念和内部粘结可有效地减小电池的质量和体积 ,同时一些新型高能电池体系 ,如锂硫聚合物电池的研究正在进行中 ,这些高能电池的体积比能量和质量比能量在以后的几年中分别有望达到 5 0 0Wh/L和 40 0Wh/kg。     

Improvement of the Transfer Efficiency of the Atomized Powder Coating System by Increasing the Conveying Air Speed

This paper deals with improvement of the transfer efficiency of powder coating by increasing the conveying air speed using the atomized powder coating (APC) system. In addition, the details of the powder-mass-flow-rate sensor, which forms the basis of the APC system and realizes sensor-based full automatic control of the system, are described. Usually, for most of the conventional powder coating systems, the conveying air of approximately 80 L/min has been recommended as the empirical standard to avoid decreasing the transfer efficiency and to specifically prevent blowing off a part of the powders deposited on the object. By contrast, for the APC system, the coating thickness in the recessed area was clearly increased with the increase of the volume of the conveying air. Thus, the increase of the volume of the conveying air from 80 to 120 L/min has yielded a 13% increase in the average coating thickness. Such an increase in the coating thickness can be ascribed to the increase of charge density on the powder particles sprayed from the gun.      

晶体硅材料太阳电池的光吸收率仿真研究

通过理论分析、仿真和实验测试,确定了影响晶体硅太阳电池太阳吸收率的主要因素,其中铝背反射器、硅片表面形貌、硼扩散对太阳吸收率的影响较为显著,硅片厚度、磷扩散的影响相对较低。采用有陷光结构的高效硅电池能明显降低电池的太阳吸收率,滤光玻璃盖片叠层电池太阳吸收率比普通玻璃盖片叠层电池低16.2%。     

金属保护层对脉冲涡流检测影响实验研究

石化设备为保温会包裹一层由隔热层与金属保护层组成的包覆层，应用脉冲涡流检测技术可实现不拆包覆层条件下设备的壁厚检测。但在实际检测中由于金属保护层材质与厚度不一致，会对检测结果与检测误差产生影响。本文搭建了脉冲涡流实验平台，分析不同类型、厚度金属保护层在不同隔热层厚度下对脉冲涡流检测信号影响，结果表明：当金属保护层为铝板与不锈钢板时，其厚度或隔热层厚度增加会增大特征值离散程度，但不影响特征曲线趋势，可通过特征曲线计算被测试件厚度；当金属保护层为镀锌钢板时，其高磁导率特性产生的屏蔽效应与感生涡流会对检测信号衰减及特征曲线产生影响。随着镀锌钢板厚度增加，不同厚度试件检测信号后期衰减差异越小。当隔热层厚度增大到50 mm时，检测信号基本重合，无法通过特征曲线计算被测试件厚度。     

涂覆光电混合涂料复合绝缘子延缓覆冰效果研究

针对复合绝缘子覆冰问题,建立了雨凇环境下复合绝缘子的传热平衡方程,并提出了临界防冰功率密度的计算方法;提出了一种光电混合涂料的制备方法:以共沉淀法制备FeMnCuO4复合金属氧化物粉末作为吸光颜料、以石墨粉作为导电颜料、室温硫化硅橡胶为基料,制备出光电混合涂料;最后对不同比例光电混合型复合绝缘子进行了覆冰试验。计算结果表明复合绝缘子临界防冰功率密度介于23.7~635.6 W/m^2之间,环境温度与风速影响显著,防冰用光电混合涂层体积电阻率介于6.38×10^5~4.47×10^6Ω·cm之间,防冰所需太阳光照强度介于144~1899 W/m^2之间;试验结果说明光电混合型复合绝缘子均有一定的延缓覆冰效果,防冰性能随涂层电阻的减小而提升。     

多层导电结构厚度电涡流检测解析模型及实验验证

从准静磁场条件下的Maxwell方程组出发,采用矢量磁位法,推导了位于任意多层导电结构上方圆柱型电涡流探头的阻抗解析模型。在阻抗计算中引入符号运算法求解矢量磁位表达式系数,大大减小了程序计算量,提高了程序效率。将阻抗解析模型应用于单层和两层导电结构厚度检测,分别研究和分析了单层厚度、铝基体上铜涂镀层厚度及铜基体上铝涂镀层厚度变化对探头阻抗变化的影响规律。仿真及实验结果表明,所推导的理论模型正确,可应用于导电结构厚度和材料属性检测的反演以及电涡流检测系统的参数优化。     

纳米TiO2对RTV硅橡胶涂膜导电的影响

为了解纳米二氧化钛(TiO2)对室温硫化(RTV)硅橡胶涂膜半导体导电行为影响的规律,采用电位-电容法结合Mott-Schottky分析技术研究了在硫酸钠的质量分数w(Na2SO4)=5%的硫酸钠溶液中纳米二氧化钛对RTV硅橡胶涂膜的导电行为的影响。研究发现,添加纳米二氧化钛粉体后,RTV硅橡胶涂膜的空间电荷层电容Csc减小,该涂膜的空间电荷层厚度增加。随着浸泡时间的延长,涂膜的空间电荷层电容Csc逐渐增加,表明涂膜的空间电荷层厚度随浸泡时间延长而有逐渐减小的趋势。添加纳米二氧化钛粉体,可促进RTV硅橡胶涂膜的导电行为由n型半导体导电特征转变为p型半导体导电特征,当所添加的纳米二氧化钛的质量分数w(TiO2)=2%时,RTV硅橡胶涂膜转变为绝缘态。     

大型水轮发电机定子线棒绝缘参数对线棒槽部表面电位分布及电场分布的影响

应用有限元分析软件COMSOL建立了定子线棒槽部模型,仿真分析了绝缘材料参数和厚度对槽部线棒表面电位分布及电场分布的影响规律。结果表明:槽部无气隙的情况下,线棒表面电位最大值出现在防晕层上、下表面的中间位置,电场最大值位于主绝缘角落内侧;对线棒表面电位有影响的是主绝缘相对介电常数、防晕层电阻率和主绝缘厚度,在常见的范围内,主绝缘电阻率和相对介电常数基本不影响槽部电场分布;防晕层表面最大电位与主绝缘相对介电常数呈正相关,与主绝缘厚度呈负相关,与防晕层电阻率的对数值呈正相关且后期影响减弱;主绝缘相对介电常数、防晕层电阻率和主绝缘厚度对槽部最大电位具有综合影响,可通过数值分析得到三元三次多项式的回归模型。     

Evaluating Dielectric Impedance Spectra using Effective Media Theories

The immittance spectra (i.e., impedance and modulus representations) are calculated for various effective medium theories, i.e., the Maxwell-Wagner (MW), Hashin-Shtrikman (HS), Bruggeman Asymmetric (BA) and Bruggeman Symmetric (BS) models, with emphasis on their individual microstructures. In addition the brick-layer (BL) model is also considered. The BL and MW-HS models yield similar single impedance arcs for a relatively low volume fraction conductive matrix (coating on the low conductivity phase). The BA model yields single impedance arcs different from the MW-HS models. The BL and MW-HS models yield virtually identical dual impedance arc behavior for a low volume fraction insulating matrix (coating on the high conductivity phase). At low volume fractions of insulating matrix, the low frequency arc due to the insulating material for the BA model is much smaller than for the MW-HS model. The BS model exhibits single impedance arc behavior when the volume fraction of conductor is above or near the percolation threshold and dual arc behavior somewhat below the percolation threshold. Equivalent circuits for these model materials are discussed, and application is made to experimental data for various electroceramic systems.     

Corrosion performance of lamellae nanostructured fluorinated organic coating applied on steel

This work investigates a new organic coating for corrosion protection. This coating is a Poly(n-butyl acrylate-b-trifluoroethyl methacrylate) diblock copolymer elaborated by Controlled Radical Polymerization and then deposited on steel. Several parameters were taken into account to evaluate their influence on corrosion protection properties: the PBA molar mass, the solvent type (THF or Dichloromethane), the thickness of coatings and the nature of the nanostructuration (lamellae or sphere). The thickness of the films was measured between 45 and 265 μm by optical microscopy and by gravimetric difference measurements. Atomic Force Microscopy (AFM) observations show a homogeneous surface of the coating with a nanostructured lamellar structure. The electrochemical behaviour was studied by Electrochemical Impedance Spectroscopy (EIS) in a sodium sulphate solution. The better corrosion resistance was obtained for coating thickness higher than 265 μm. On the other hand, poor results were obtained using a PBA high molar mass and dichloromethane as solvent.     

Cine-MRI assessment of cardiac function in mice anesthetized with ketamine/xylazine and isoflurane

Since small-animal MRI generally requires anesthesia, the effect of the anesthetic regimen on the explored organ(s) has to be taken into account for study interpretation. In this work, we assess the influence of ketamine/xylazine and isoflurane anesthesia on left-ventricular (LV) function in the mouse in vivo by cine-MRI. Three groups of animals were anesthetized with ketamine/xylazine (n = 13) and two different concentrations of isoflurane (1.25%, n = 12 and 2.00%, n = 12) delivered in O₂/N₂O mix. Long- and short-axis cine-MRI was performed to measure end-diastolic volume, stroke volume, ejection fraction and LV wall thickness. Ketamine/xylazine significantly reduced heart rate, cardiac output and wall thickness, but increased stroke volume and end-diastolic volume compared with both isoflurane groups. No differences across all groups were observed in ejection fraction or systolic wall thickening. Breath rate under isoflurane was significantly lower and concentration dependent, whereas heart function was independent of concentration in all measured parameters. These findings are in agreement with echocardiography and catheterization studies. Isoflurane is advantageous for MR studies because it better maintains cardiac function. Taking into account previously obtained myocardial perfusion measurements, isoflurane concentration should, however, be maintained at the minimum required for a stable sleep even if cardiac function is unaffected by higher isoflurane concentrations.