不同压力下的热压加工对含Mn块体纳米晶Fe3Al组织和性能的影响

对铝热反应熔化制备的含10wt%Mn块体纳米晶Fe3Al材料在800℃和1000℃温度下,采用不同压力进行热压加工,利用XRD研究热压加工前后纳米晶粒尺寸的变化,并测试硬度变化和压缩率。结果显示,不同温度、压力下热压加工后,晶粒尺寸变化不大;热压加工后,材料的硬度有所上升,但温度和压力对硬度影响不大;热压加工中,材料表现出较好的塑性变形,并随着热压压力的增大,材料压缩率逐渐增大,但温度对材料的压缩率影响不明显。热压加工后,块体纳米晶Fe3Al材料几何尺寸得到了增大。     

利用开关卡尔曼滤波器的目标跟踪技术研究

为了使机器人视觉伺服控制系统的目标跟踪精度得到进一步提高,构建一种基于开关卡尔曼滤波器的视觉伺服控制系统。研究视觉伺服的目标跟踪原理,推导相关的数学模型,并分析跟踪误差产生的原因;针对图像采集和处理引入的延时问题,通过卡尔曼滤波估计得到目标运动的速度信息,以此作为前馈量输入视觉伺服控制器,补偿由于目标运动和延时造成的跟踪误差;为了解决卡尔曼滤波器由于目标运动的突然变化而降低估计性能的问题,引入运动监视器以在目标运动突然变化时发出开关信号并重置卡尔曼滤波器;最后对该算法进行实验与仿真。结果表明:基于卡尔曼滤波器的视觉伺服控制器能把跟踪误差控制在1 mm以内,而开关卡尔曼滤波器能有效地减少因目标运动状态突然变化而产生的跟踪误差。     

基于平行耦合线和开路枝节的小型带通滤波器设计

为了解决耦合线滤波器谐波抑制问题,提出了一种新的结构简单的平行耦合线带通滤波器.该滤波器由平行耦合线和开路枝节组成.首先基于耦合线带通滤波器的等效电路图,通过奇偶模理论得到设计方程,并设计了带通滤波器;分析了滤波器特性与电参数之间的关系;通过仿真优化得到了滤波器的物理尺寸;制备并测试了滤波器的S参数,仿真结果和测试结果基本一致.该滤波器具有结构简单、面积小等优点,并通过引入传输零点实现了较宽的阻带抑制和较好的选择性.     

发电机局部放电甚高频在线监测现场试验分析

笔者研制了发电机局部放电甚高频在线监测系统,该系统基于双传感器定向耦合的原理进行信号采集,利用数字脉冲逐个识别技术通过软件来实现干扰抑制。结合在四川龚嘴电厂、福建池潭电厂等地的现场实验分析,验证了该系统的测试效果及其抗干扰能力。通过对某电厂发电机连续在线监测及故障预警的分析,证实了相比单一的放电量分析,采用统计参数趋势分析的方法能够更有效地反映发电机放电变化趋势。     

应用己酸菌及人工培养窖泥提高浓香型青稞酒质量的研究

详细叙述了己酸菌及窖泥的培养方法,以及应用己酸菌及人工培养窖泥提高浓香型青稞酒质量的研究全过程     

Mapping of Ras-related GTP-binding proteins by GTP overlay following two-dimensional gel electrophoresis

For identification of Rab, Rac, Rho, Ral, Rap, and Arf proteins on two-dimensional polyacrylamide gels, we have expressed full-length cDNAs of members of these protein families with the T7 RNA polymerase-recombinant vaccinia virus expression system. Membrane preparations from cells expressing the cDNAs were subjected to high-resolution two-dimensional polyacrylamide gel electrophoresis followed by [alpha-32P]GTP ligand blotting. We have mapped 28 small GTP-binding proteins relative to their isoelectric points and according to their molecular weights and by immunoblotting with specific antibodies. Rab and Rho proteins could be specifically identified by extraction of streptolysin O-permeabilized Madin-Darby canine kidney (MDCK) cells with Rab- and Rho-GDP dissociation inhibitor. We applied the reference mapping to analyze the GTP-binding patterns of synaptosome fractions from rat brain. The purified synaptosomes exhibited specific enrichment of Rab3a, Rab5a, Ral, and several other GTPases. This approach and the map we have produced should provide a useful aid for the analysis of the expression and localization of members of all families of small GTP-binding proteins in various cell types and subcellular fractions.     

Evidence for plasmid-associated crystal toxin production in Bacillus thuringiensis subsp. israelensis

Three crystalliferous (Cry+) strains of Bacillus thuringiensis subsp. israelensis (serotype 14) that produce parasporal protein crystals toxic to dipteran larvae and several acrystalliferous (Cry-) mutants, either induced or spontaneously derived from a single Cry+ parent, were examined for the presence of covalently closed circular (CCC) DNA in attempts to correlate toxin production with the presence of a specific plasmid. The plasmid profiles of both Cry+ and Cry- variants were analyzed by both a cleared lysate- and a modified Eckhardt lysate-electrophoresis technique. All of the Cry- mutants derived from the Cry+ parental strain had lost a 4.0- to 4.4-megadalton (Mdal) plasmid. Bioassay data confirmed loss of toxin production by the Cry- variants. All three Cry+ strains, including the parent of the Cry- strains, contained CCC plasmids DNAs of the following approximate molecular weights: 4.0 to 4.4, 5.2 to 6.0, and 11.4 to 13.0 Mdal. One Cry+ strain contained an additional CCC plasmid of 6.7 to 7.2 Mdal. The plasmid patterns for several Cry- derivatives differed in other respects from the pattern for their parent strain. The various Cry+ and Cry- strains could be distinguished either by phenotypical differences in antibiotic sensitivity, crystal production, and toxicity, or by differences in their plasmid profiles.