Study on switched reluctance generator

The linear and non-linear math models of the switched reluctance generator (SRG) in generator mode were established in this work. The phase current and energy conversion process during generator operation were simulated by the linear math model. The non-linear math model was used to analyze the characteristics of the SRG operation in self-excitation mode and in separately-excitation mode. Some important findings on how the SRG is operated and controlled were obtained in this study, which provides theoretical basis for further design and experimental study.     

Cellular automata modeling of pedestrian＇s crossing dynamics

Cellular automata modeling techniques and the characteristics of mixed traffic flow were used to derive the 2-dimensional model presented here for simulation of pedestrian's crossing dynamics. A conception of "stop point" is introduced to deal with traffic obstacles and resolve conflicts among pedestrians or between pedestrians and the other vehicles on the crosswalk. The model can be easily extended, is very efficient for simulation of pedestrian's crossing dynamics, can be integrated into traffic simulation software, and has been proved feasible by simulation experiments.     

1990年代以来美国社会的两极化发展

20世纪90年代以后,随着以信息产业、飙升的股市为代表的新经济的来临以及经济全球化的加速推进,美国经济蓬勃发展,经济总量迅速提高,但与此同时,美国国内的贫富鸿沟却日益扩大、社会分配不公愈益严重。而上述促进美国经济迅猛发展的因素却在不同程度上对美国社会的贫富分化起到了推波助澜的作用。这必然威胁到美国经济持久良性的发展、威胁到美国社会的生存根基。     

基于绿色设计准则的塑料门窗铣削机设计

介绍了绿色设计在技术先进性,环境、材料和结构等方面的准则,并运用于塑窗锯铣加工中心的铣削机设计中,表明绿色设计可从技术上保证安全,可靠,经济地实现产品的各项功能和性能,同时只有在设计阶段将产品的“绿色度”作为设计目标,才能取得理想的设计结果。     

在定量分析实验中正确树立"量"的概念

从学生在定量实验过程中存在的问题 ,提出了正确树立“量”的概念的重要性及采取的措施     

金纹细蛾的生物学特性及防治研究

金纹细蛾在河北冀东地区一年发生 5代 ,以蛹越冬 ,主要以幼虫潜食植物叶肉为害。各代成虫发生盛期分别为 :越冬代 4月 15～ 18日 ;第一代 5月 2 3～ 2 8日 ;第二代 6月 2 2～ 7月 2日 ;第三代 7月 2 0日～ 8月5日 ;第四代 8月 16日～ 9月 4日。利用性诱剂防治金纹细蛾效果显著 ,5个诱扑器共诱雄虫 2 584 9头。利用树干注射器注射 4 0倍速灭杀丁防治效果达 53%。     

制皂废水物化处理的探讨

以制皂废水经脱硫除尘塔后的出水为研究对象,通过气浮和混凝沉降的中试对比,提出混凝沉应用于出塔水的处理的工艺条件及组合混凝剂的最佳投加量。实验表明,混凝沉降能有效降低制皂废水的COD浓度,处理水可回用于脱硫除尘;同时,混凝沉降后出水可生化性较好,通过生化处理,可实现达标排放。     

Antibody neutralization and escape by HIV-1

Neutralizing antibodies (Nab) are a principal component of an effective human immune response to many pathogens, yet their role in HIV-1 infection is unclear. To gain a better understanding of this role, we examined plasma from patients with acute HIV infection. Here we report the detection of autologous Nab as early as 52 days after detection of HIV-specific antibodies. The viral inhibitory activity of Nab resulted in complete replacement of neutralization-sensitive virus by successive populations of resistant virus. Escape virus contained mutations in the env gene that were unexpectedly sparse, did not map generally to known neutralization epitopes, and involved primarily changes in N-linked glycosylation. This pattern of escape, and the exceptional density of HIV-1 envelope glycosylation generally, led us to postulate an evolving 'glycan shield' mechanism of neutralization escape whereby selected changes in glycan packing prevent Nab binding but not receptor binding. Direct support for this model was obtained by mutational substitution showing that Nab-selected alterations in glycosylation conferred escape from both autologous antibody and epitope-specific monoclonal antibodies. The evolving glycan shield thus represents a new mechanism contributing to HIV-1 persistence in the face of an evolving antibody repertoire.     

尺度分离法在云南单点性暴雨诊断分析中的应用

 应用低通滤波器分离天气尺度和次天气尺度的运动,对云南罗平地区的一次单点性暴雨过程的各种物理量进行诊断分析.发现天气尺度的系统为次天气尺度的系统提供了暴雨发生的适合的环境场,而次天气尺度的系统是导致罗平地区单点性暴雨发生的直接原因.     

"时时在线"的安全性隐患与个人防火墙保护

分析“时时在线”的安全性隐患、个人防火墙的安全保护功能及其重要性和安全局限性,给出该环境下家庭LAN和PC机的防攻击保护策略．