硅烷自组装膜对制备于多孔性基底上导电聚吡咯薄膜性能的影响

采用硅烷偶联剂对在多孔性绝缘Al2O3膜基底上形成的导电聚吡咯(polypyrrole, PPy)薄膜的形貌及导电性能进行了改善,并探讨了硅烷自组装膜与导电PPy薄膜的形成机理.用硅烷偶联剂对Al2O3膜表面进行改性后,形成了与基底牢固结合的硅烷自组装膜,然后通过化学聚合法在自组装膜上制备得到了均匀致密的PPy薄膜.结果表明:硅烷偶联剂有效地改善了PPy薄膜的均匀性及其与基底的附着性,电导率从5.4S/cm提高到了16.6S/cm.     

Si3N4陶瓷/Nb/Cu/Ni/Inconel 600界面反应层形成机制研究

观察分析了Si3N4陶瓷/Nb/Cu/Ni/Inconel600界面处反应层的形貌、元素分布、反应层中的相结构、界面反应以及反应层的生长规律,研究了Si3N4陶瓷/Nb/Cu/Ni/Inconel600界面处反应层的形成机制.研究结果表明:在连接过程中,Cu层首先熔化,Nb、Ni向液态Cu中扩散溶解形成Cu-Nb-Ni合金,液态合金中的Nb和Ni向Si3N4表面扩散聚集并与Si3N4反应形成反应层;Si3N4侧的反应层主要物相是NbN和Nb、Ni的硅化物,Ni基合金侧反应相主要是NbNi3和Cu-Ni合金;在连接温度为1403 K的条件下,随着连接时间的增加,界面反应层厚度先快速增加,再缓慢增加.     

ZnO/SiC/Si异质结构的特性

用MOCVD方法在p型单晶Si（100）基片上外延SiC层,再用直流溅射在SiC层上生长ZnO薄膜,制备出ZnO／SiC／Si异质结构,用XRD和AFM分析了ZnO／SiC／Si和ZnO／Si异质结构中表层ZnO的结构和形貌的差别,研究了这种异质结构的特性．结果表明,在Si（100）基片上外延生长出的是高取向、高结晶质量的SiC（100）层．这个SiC层缓冲层使在Si基片上外延生长出了高质量ZnO薄膜,因为ZnO与SiC的晶格失配比ZnO与Si的晶格失配更低．     

离子液体/聚合物电解质在双电层电容器中的应用

以P(VDF-HFP)为基体,与离子液体1-乙基-3-甲基咪唑钅翁四氟硼酸盐(EMIBF4)和1-丁基-3-甲基咪唑钅翁六氟磷酸盐(BMIPF6)制备出离子液体/聚合物电解质凝胶膜,并组装了活性炭电极双电层电容器(EDLC)。基于EMIBF4/P(VDF-HFP)和BMIPF6/P(VDF-HFP)聚合物电解质(质量比2∶1)的双电层电容器,比电容分别为38.5 F/g和20.9 F/g。基于EMIBF4/P(VDF-HFP)的双电层电容器显示了优良的电化学性能。     

改进的Kriging技术实时重构区域电离层foF2的分布

改进了kriging技术重构电离层F2层临界频率foF2的方法,利用国际参考电离层IRI-2001模型作为背景场,通过拟合国际参考电离层模型得到“等效太阳黑子数”,并利用kriging技术来完成区域电离层的重构,是区域电离层重构的一种方法,它适合重构区域内电离层探测站较少的情况。与直接利用实测临界频率进行kriging重构相比,改进的kriging技术提高了重构的精度和稳健性。也表明了背景电离层模型在电离层重构中的重要作用。     

粘土固化浆液在强透水层中防渗试验

防渗用粘土浆液中加入少量粘土浆液固化剂,被注浆的透水地层,其结石强度和渗透系数值达到防渗要求。用粘土固化浆与水泥浆在坝基强透水地层做了高喷截渗时比试验。     

内衬GFRP防护复合管壁原缺陷坑处应力重分布规律分析

为了深入研究内衬GFRP防护复合管壁在其原管道内腐蚀缺陷坑处的应力重分布状态以及其修复的效果,利用弹塑性力学中的平衡微分方程,建立了管道内腐蚀缺陷处的数学模型,采用有限单元法建立了含单个腐蚀缺陷的管道模型,并通过改变腐蚀缺陷坑的深厚比,将修复前后腐蚀缺陷坑处的应力状态进行对比分析。分析结果表明,腐蚀缺陷坑的深厚比对管道的应力分布有着显著的影响,所以在进行管道安全评估时应注意腐蚀坑深度的影响;在腐蚀缺陷坑深厚比0.1到0.8的分次增加的过程中,管壁腐蚀缺陷处的周向应力,径向应力,Mises应力都有增大的趋势;修复前腐蚀缺陷坑处的周向应力和Mises应力相近,径向应力较前两者小,三者中周向应力最大;在修复前后,管道腐蚀缺陷处的控制应力一般是周向应力,管道的失效可依据周向应力进行判断;修复后的内衬GFRP防护复合管壁,原始腐蚀缺陷坑处发生了应力重分布,其周向应力与Mises应力均有减小,修复效果明显。     

Effects of free stream turbulence on a turbulent boundary layer on a flat plate with zero pressure gradient part IV: Calculation of the flow field

The effects of free stream turbulence on a turbulent boundary layer were calculated by using a k-ϵ two-equation model. The calculations were performed with respect to velocity profiles on a flat plate, wall shear stress, turbulence energy, integral length scales of turbulence, and decay of free stream turbulence, and the results were compared with the experimental results. The energy of the free stream turbulence and the dissipation values at the leading edge of the flat plate were used as the initial calculation conditions. These initial values of dissipation were determined from the integral length scales of the free stream turbulence at the leading edge. The calculated wall shear stress increased with the free stream turbulence and integral length scales of turbulence. The velocity profiles and turbulence energy agreed well with the experimental results, and the effects of free stream turbulence on the wall shear stress agreed fairly well with those observed in experiments. © 1997 Scripta Technica. Inc. Heat Trans Jpn Res. 25 (2): 65–75, 1996     

Experimental analysis of 2D-unsteady temperature field by using Mach-Zehnder interferogram images

A measurement method for an unsteady temperature field by using a Mach-Zehnder interferometer and image processing technique is presented. In this study, the results measured by this method were compared with the calculated results under Reynolds numbers (Re = UL/v) ranging to less than 350 in the steady-state. The unsteady characteristics of the local Nusselt numbers (Nu_x = α_xL/λ) around an elastically vibrating plate were investigated under the conditions that the reduced frequency (N = 1/Ro) ranged from 4.8 to 8.6 and the amplitude of vibration was kept small relative to the plate length. In this study it was clarified that the distributions of the Local Nusselt numbers were observed flutteringly, and that the phase of the time-averaged Nusselt number is delayed compared to the phase of the velocity at the trailing edge. These results indicate that the enhancement of the time-averaged heat transfer coefficient around the vibrating plate depended on the Rossby number. © 1997 Scripta Technica. Inc. Heat Trans Jpn Res. 25 (2): 88–102, 1996     

PEMFC的自增湿膜电极结构和性能研究

设计并制作了一种新结构的质子交换膜燃料电池(PEMFC)自增湿膜电极。其特点是在催化层和扩散层之间建立水管理层(WML),WML由不同质量比的炭黑和聚四氟乙烯(PTFE)组成双层结构。为了减小气体反应物的扩散传质阻力,在WML的制作过程中加入了具有高分解温度和高溶解度的(NH4)2SO4造孔剂。用单体PEMFC的电流密度-电压曲线评价了膜电极在外增湿和自增湿方式下的极化特性;用环境扫描电子显微镜(ESEM)表征了膜电极的表面形貌和孔结构。实验结果表明,所制备的膜电极具有良好的水管理能力,在较宽的电流区域内具有良好的电化学性能。