9Cr13Mo3Co3Nb2V马氏体不锈钢微观组织研究

对不同热处理状态下的微观组织结构进行了研究.采用物理化学相分析技术研究了9Cr13Mo3Co3Nb2V退火、淬火以及最终热处理制度下析出相的类型、含量及组成结构式.并用X射线小角散射(SAXS)(small angle x-ray scatter)分析了不同热处理制度下析出相在不同粒度间隔中的质量分布.结果表明:①9Cr13Mo3Co3Nb2V钢退火状态的组织为珠光体 碳化物(M23C6,MC和M6C),淬火状态组织为马氏体 碳化物(M23C6和MC),最终热处理状态的组织为回火马氏体 碳化物(M23 C6,MC和M3C);②小颗粒(≤300nm)碳化物析出相粒度分析表明,9Cr13Mo3Co3Nb2V钢退火、淬火状态析出相平均粒度相差不大,粗大颗粒较多,而最终热处理状态的析出相平均粒度明显减小,且细小颗粒比例较大.     

基于ASP.NET技术的工程技术文件发布系统应用与开发

工程文件管理在航空公司的各项工作中占据重要地位。本文介绍基于ASP.NET技术的工程技术文件发布系统的应用与开发。     

基于等高线图与小波变换的3D地形匹配算法研究

提出一种新的基于边缘的3D地形匹配算法。在算法中，一种结构紧凑的特征“等高线图”，用于表示参考高程图(DEM)及从实时数据恢复的高程图，这样3D地形匹配转化为基于等高线的匹配，即边缘(平面曲线)匹配问题。在边缘匹配过程中，首先用一种具有平移，旋转，尺度不变性的规范化小波描述子描述边缘。其次提出了一种基于小波系数域的快速边缘匹配算法，并分析了运算复杂性。由匹配成功的边缘对提取控制点的坐标。讨论了图像变换模型及基于最小均方根误差准则的图像变换参数估计方法。用真实地形实验表明该算法匹配精度高，计算速度快。最显著的特点是该算法抗噪声能力强。     

一种新型液压泵变排量机构的设计与仿真

为提高一体化电液作动器(EHA)的性能,对新型EHA中广泛使用的变排量液压泵中的变量机构进行了优化设计。采用锥蜗轮蜗杆传动代替了原来的齿轮传动体系并与泵壳体进行了一体化设计,采用solidworks进行了三维实体化建模,运用AMESim搭建了改进前后EHA系统的仿真模型并进行对比分析。经过仿真实验,改进后的EHA系统在整体刚度提升了31%,频率响应提升了11.2%,显著改善了系统性能,验证了设计的正确性。     

NASICON固体电解质SO2传感器的特性研究

采用溶胶-凝胶法合成NASICON固体电解质材料,并以其为基体材料制作管式SO2传感器,敏感电极采用Na2SO3-30?SO4或者Na2SO4-30?SO4(摩尔比)复合硫酸盐.SO2浓度在(10～100)×10-6体积分数范围内,两种器件的灵敏度分别为81.1和60.6mV/decade.敏感电极为Na2SO3-30?SO4的元件响应和恢复时间分别为28.2 s和57.7 s;敏感电极为Na2SO4-30?SO4的元件响应和恢复时间分别为39.8 s和67.4 s.     

O2 evolution and cyclic electron flow around photosystem I in long-term ground batch culture of Euglena gracilis

Based on the purpose of better exploring the function of green producers in the closed aquatic biological life support system, the condition of dynamic O₂ evolution and performance of cyclic electron flow around photosystem I (CEF-PSI) in long-term ground batch culture of Euglena gracilis were studied, the relationship between linear electron flow (LEF) and CEF-PSI was revealed, the function of CEF-PSI was investigated. Excellent consistency in O₂ evolution pattern was observed in cultures grown in both closed and open containers, O₂ evolution was strictly suppressed in phase 1, but the rate of it increased significantly in phase 2. CEF-PSI was proposed to be active during the whole course of cultivation, even in the declining phase 3, it still operated at the extent of 47–55%. It is suggested that the relationship between LEF and CEF-PSI is not only competition but also reciprocity. CEF-PSI was proposed to contribute to the considerable growth in phase 1; it was also suggested to play an important protective role against photosystem II (PSII) photoinhibition at the greatly enhanced level (approximately 80–95%) on the 2nd day. Our results in this research suggest that E. gracilis had very particular photosynthetic characteristics, the strict O₂ evolution suppression in the initial culture phase might be a special light acclimation behavior, and CEF-PSI could be an important mechanism involved in this kind of adaptation to the changeable light environment.     

Preparation and Mechanical Properties of Glass Coats with High Temperature Radar Absorber

BaO-La2O3-B2O3 (BLB) glass, suitable to be used as a sealing between metals, was chosen to be the binder in preparing glass coats on the Ti-alloy substrate. The SiCN nano-powder was introduced as the filler for the absorbing coat because it is considered to be a good high temperature absorber. The effect of the coating temperature and coating time on the tensile strength of the glass coat was investigated and the proper coating parameters to get good mechanical properties were determined. In addition, the effects of the SiCN content on the tensile strength of the absorbing coat were also discussed. Results show that it is possible to prepare the glass coat using the BLB glass as a binder. That the coat formed at 730 ℃ for 30 min has the best tensile strength witnesses 730 ℃, 30 min to be the proper parameter to prepare the glass coat. The BLB glass coat without SiCN powder possesses good tensile strength and the introduc-tion of the SiCN absorber into the glass coat will lower the tensile strength. As the SiCN content increases, the tensile strength of the absorbing coat decreases, which could be attributed to the aggregation of SiCN in the coats.     

Sc和Zr复合微合金化在Al-Mg合金中的存在形式与作用

研究了微量Sc和Zr复合合金化对Al Mg合金显微组织与拉伸性能的影响。结果表明 :Sc和Zr复合微合金化可显著提高Al Mg合金的强度。Al Mg Sc Zr合金凝固过程中形成的初生Al3 (Sc ,Zr)复合粒子具有极强的晶粒细化作用 ,次生Al3 (Sc,Zr)质点与Al Mg Sc合金中次生Al3 Sc质点相比析出密度大大增加、分布更加均匀弥散、抑制再结晶的能力更为强烈。Sc和Zr复合微合金化大大促进了微量Sc在Al Mg合金中的强化作用。由于Zr的价格比Sc便宜很多 ,采用Sc和Zr复合微合金化可减少铝合金中Sc的加入量 ,从而降低合金的成本。     

浸渍-提拉法制备WO3薄膜的气敏性能研究

采用溶胶-凝胶方法制备WO3前驱液,利用浸渍-提拉法使其成膜。通过XRD分析了不同热处理温度对WO3晶体结构的影响,通过SEM图观察了不同提拉次数的WO3薄膜形貌。所得WO3薄膜的微观结构和气敏性能随提拉次数不同而有很大差异,提拉1次、2次的样品薄膜不连续,电阻过大,灵敏度无法测量;提拉3次成膜的样品电阻稳定,气敏性能最好,对NO2有很高的灵敏度。     

一种基于PKI/数字证书的SNMPv3安全模式

SNMPv3的用户安全模式在协议安全性和系统易用性等方面存在严重不足.针对网络安全设备管理这一特定领域,提出了一种基于PKI/数字证书的安全模式,实现了SNMP用户身份管理和通信双方安全握手过程,使得SNMP网管系统的易用性和安全性都得到了很大提高.最后分析了新的安全模式对系统性能的影响.