高频高压电源中倍压器的设计

倍压器是高压电源的一个重要组成部件。通过MATLAB仿真及实验测试,研究了半臂逆对称式倍压器倍压级数、电容容量对高压电源性能的影响规律。接着在仿真研究的基础上进行实际测试,并对30kV、5mA的高压电源的性能进行了优化。在以可控硅(SCR)为功率转换电路的30kV、5mA的电源设计中,研究结果表明在一定的工作频率条件下,倍压器参数的优化对提高电源的效率、降低输出电压的纹波值、增强电源的稳定性具有显著的影响,为高频高压电源的设计提供了理论指导意义。     

IUKF neural network modeling for FOG temperature drift

A novel neural network based on iterated unscented Kalman filter （IUKF） algorithm is established to model and com- pensate for the fiber optic gyro （FOG） bias drift caused by temperature. In the network, FOG temperature and its gradient are set as input and the FOG bias drift is set as the expected output. A 2-5-1 network trained with IUKF algorithm is established. The IUKF algorithm is developed on the basis of the unscented Kalman filter （UKF）. The weight and bias vectors of the hidden layer are set as the state of the UKF and its process and measurement equations are deduced according to the network architecture. To solve the unavoidable estimation deviation of the mean and covariance of the states in the UKF algorithm, iterative computation is introduced into the UKF after the measurement update. While the measure- ment noise R is extended into the state vectors before iteration in order to meet the statistic orthogonality of estimate and mea- surement noise. The IUKF algorithm can provide the optimized estimation for the neural network because of its state expansion and iteration. Temperature rise （-20-20℃） and drop （70-20℃） tests for FOG are carried out in an attemperator. The temperature drift model is built with neural network, and it is trained respectively with BP, UKF and IUKF algorithms. The results prove that the proposed model has higher precision compared with the back- propagation （BP） and UKF network models.     

Electromagnetic behavior of two-dimensional quasi-crystal left-handed materials with dendritic unit

We demonstrated a two-dimensional quasi-crystal dendritic structure model with negative permeability. The microwave transmission and reflection properties of periodic and quasi-crystal dendritic structure mediums with varied angle incidence were measured. The results showed that the resonant peaks of quasi-crystal negative permeability samples and left-handed samples had tiny shift with the altering of incident angle. Because of the influence of coupling between quasi-crystal dendritic cells, the resonance of the entire material was enhanced or weakened. The quasi-crystal dendritic structure model will provide an easy method to design isotropic left-handed materials （LHMs）.     

ZnO/WO_3纳米片薄膜的光电催化性能研究

采用水热法在不锈钢基底上制备WO3纳米片阵列,然后将其浸渍于不同浓度Zn(NO_3)_2溶液中以负载ZnO纳米颗粒,从而制备出ZnO/WO_3纳米片薄膜。采用场发射扫描电镜(FESEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、紫外-可见吸收光谱(UV-Vis)和电化学阻抗图谱(EIS)等方法对ZnO/WO_3复合薄膜的形貌、结构、物相组成和光电性能等进行分析,重点考察了薄膜电极对亚甲基蓝(MB)的光电催化降解性能。结果表明,WO_3纳米片均匀垂直于基底生长,Zn元素以ZnO颗粒的形式分布在WO_3表面;ZnO的引入促进了WO_3中产生的光生电子-空穴对的分离,从而使ZnO/WO_3复合薄膜表现出比纯WO_3薄膜更优异的光电性能和光电催化活性;在Zn(NO_3)_2浸渍液浓度为20mmol/L时,所制ZnO/WO_3复合薄膜具有最佳的光电催化性能,在MB溶液初始浓度为10mg/L、外加偏压为0.8V、光照1h的条件下,采用该样品对MB的降解率达96.5%,并且复合薄膜具有良好的循环稳定性,在重复使用5次后,对MB的光电催化降解效率没有明显降低,有望在实际污水处理中得到应用。     

观光列车旅游初探——兼论青藏铁路开展观光列车旅游的可行性

观光列车旅游在国外是具有悠久发展历史,成熟的高端休闲旅游产品.青藏铁路的开通,将带来中国观光列车旅游的新时代.通过对观光列车旅游的发展及相关文献的研究,初步定义了观光列车旅游,并对青藏铁路开展观光列车旅游的可行性进行了分析.     

关于保持内蒙古城镇化稳步发展的思考

“十一五”时期,内蒙古自治区经济社会发展的主要目标：到“十一五”末内蒙古的城镇化水平达到55%左右.现阶段内蒙古人口城镇化已进入中期加速阶段,但在多年推进城镇化的过程中也积累了一些问题,如何有效地解决这些问题,对内蒙古城镇化建设继续平稳发展有重要意义.本文借助ARCGIS软件对2003年内蒙古旗县统计资料进行处理,发现内蒙古旗县城镇化城市规模偏小,总数偏少,分布散的,辐射带动力弱的问题,以及城镇化率与城镇化实质存在偏差,产业结构、经济结构不尽合理,城乡差距加大,城市设施水平大多没有跟上城镇化速度的问题.为保证内蒙古城镇化快速平稳前进,要继续重点发展大中城市,进一步搞好小城镇建设;产业结构调整与城镇化发展良性互动;关注“三农”问题,保证城镇化进程稳步前进;搞好基础设施建设,提高城镇化质量.     

河南省粮食产量周期波动分析

利用1951--2005年河南省粮食产量统计数据,应用波动理论和周期理论分析河南省粮食产量波动规律,考察河南省粮食产量波动的历史过程和数量特征．结果表明,河南省粮食产量波动具有短周期的显著特征,平均波动周期3.3年左右,波幅较小,扩张期略长于收缩期．     

Recombinant soluble TRAIL induces apoptosis of cancer cells

TRAIL is a tumor necrosis factor family member that selectively induces apoptosis of cancer cells but not of normal cells. To develop TRAIL into a potential cancer drug, three different sizes of soluble TRAIL fragments, including sTRAIL(74—281), sTRAIL(95—281) and sTRAIL(101—281), were expressed in E. coli and purified to homogeneity. Apoptosis assays indicated that sTRAIL(95—281) and sTRAIL(101—281), but not sTRAIL(74—281), can potently induce apoptosis of various cancer cell lines in 6 h, suggesting that the N-terminal fragment of aa101 has inhibitory effect on TRAIL-induced apoptosis. Moreover, we found that some cancer cells were resistant to TRAIL and the resistant cells could be converted into sensitive cells by treatment with the protein synthesis inhibitor cycloheximide, suggesting that one or more short-lived proteins are responsible for cells’ resistance to TRAIL.     

污染稻麦籽实中镉和铅的分布及其存在形态

组织化学及生物化学分析表明：污染稻麦籽实中Ｃｄ和Ｐｂ呈不均－分布,胚中质量量显著高于胚乳,且皮层和颖壳中量也较高,但胚乳中的蓄积总量最多;在籽实主要营养成分中Ｃｄ和Ｐｂ以与蛋白上结合的形态为主,其中与谷蛋白、球蛋白的结合量最多。     

师专公共课与学生能力培养

本研究以文山师专学生11门公共课的成绩为材料,采用因子分析的方法,得出11门公共课主要培养4种共同能力：现代认知能力、综合教育能力、教学基本功、生活适应能力。思想品德修养、普通话口语训练、书法、教育学等课程在师专生共同能力培养中起着较突出的作用。从能力培养的角度看,师专公共课程的设置与现代教育发展的趋势是相呼应的,它在师范生能力培养中的作用是学科专业课不能取代的。要确保师专教学质量,就要充分发挥公共课能力培养的作用。