State feedback controller design of networked control systems

This paper is concerned with the controller design of networked control systems (NCS). A new model of the NCSs is provided under consideration of both the network-induced delay and the data packet dropout in the transmission. In terms of the given model, a controller design method is proposed based on a delay-dependent approach. The feedback gain of a memoryless controller and the maximum allowable value of the network-induced delay can be derived by solving a set of linear matrix inequalities. Two examples are given to show the effectiveness of our method.     

An improved model for four-terminal junction field-effecttransistors

The junction field-effect transistor (JFET) has isolated top- and bottom-gate terminals and therefore is useful for signal mixing applications. Existing models for the four-terminal JFET often have the same form as the three-terminal JFET model, however, in which only a single pinch-off voltage is used to describe the current-voltage characteristics. In this paper, a more general four-terminal JFET model is developed. Two different pinch-off voltages are involved in the improved model to account more comprehensively for the effects of both depletion regions associated with the top- and bottom-gate junctions. Results simulated from a device simulator are also included in support of the model     

基于改进二分法的马斯京根法入流过程反演分析

针对马斯京根法反演洪水过程中一般反演单峰洪水过程,较少考虑双峰或多峰洪水过程,在分析总结马斯京根法反演中存在锯齿状、正负交错甚至无法继续计算的问题及改进方法的基础上,提出改进的二分法以解决双峰甚至多峰的洪水过程反演,并将其应用于浙江省飞云江干流马屿站的洪水过程反演中。结果表明,除个别出流误差较大外(超过10%),大部分出流误差在5%以内,基本达到水文计算的精度要求,同时入流总量与出流总量近似相等,基本满足水量平衡,反演结果合理,可用于入流过程的反演计算。     

双环戊二烯-马来酸酐共聚物的合成、表征及其与聚氨酯反应性共混研究

合成了双环戊二烯-马来酸酐交替共聚物(DCPD-co-MA),产率约25%。采用红外、核磁共振氢谱和碳谱对共聚物进行了表征,差热分析和热重分析表明该共聚物具有较好的热性能,其T_g为210℃,起始热失重温度为310℃。采用反应性共混方法合成了DCPD-co-MA与聚氨酯(PU)的共混物(PU/DCPD-co MA),反应温度为80℃。该共混物具有较好的综合性能,其起始热失重温度较纯PU提高了约41℃,共混后,其耐热性能有较大改善。     

固相含量和密度对高密度钻井液流变性影响的实验研究

高密度钻井液体系的研究和应用中,流变性是重要的衡量标准,而固相含量和密度又是影响高密度钻井液流变性最重要的因素。通过机理分析,并根据大量室内试验研究了在高温条件下,高密度钻井液固相含量和密度的变化对其流变性能的影响规律和程度。通过对钻井液表观黏度、塑性黏度、动切力和静切力等流变参数的变化进行测定和计算,对不同固相含量（2%～6%）的高密度钻井液流变参数曲线变化进行对比得出:含土量增大,钻井液的黏度增大;高密度钻井液的流变性受固～相含量大小和温度的影响明显、受压力和添加剂的影响较小。该试验研究结果将对钻井现场高密度钻井液的应用具有重要的借鉴作用。     

Diagnosis of stator winding insulation of large generator based on partial discharge measurement

The Stator winding insulation is aged by exposure to a combination of thermal, electrical, mechanical, and environmental stresses. Diagnosis of stator winding insulation is an important measure of ensuring the safe operation and extending the remaining life of large generator. In the paper, two new parameters are proposed for the diagnosis of stator winding insulation based on the test results of multistress accelerating aging test of stator bars. The test results show that the skewness of partial discharge phase resolved distribution and the high-frequency crest of partial discharge (PD) impulse change much more remarkably with the aging time than do the conventional parameters. Therefore, the two parameters could be considered as characteristic parameters for the diagnosis of stator winding insulation of the large generator. With these characteristic parameters, authors successfully assessed the insulation condition of actual stator bars removed from several large generators.     

KM496GB型柴油机机油压力低的原因分析及对策

通过对KM496GB柴油机机油压力低的试验分析表明,引起故障主要原因有:机油泵故障,限压阀未备紧,机油泵油量偏低,并介绍了所采取的相应措施。     

有机层厚度对OLED性能的影响

采用真空蒸发的方法制备出玻璃衬底ITO／TPD／Alq／A1结构的有机发光器件(OLED)。改变有机层的厚度, 比较不同厚度下OLED的各项性能的差异,包括工作电压,发光效率。实验发现无论增大空穴传输层TPD的厚度 抑或是发光层Alq的厚度都会增大器件的工作电压。发光层Alq厚度的增大还能引起发光效率的增大,而TPD厚 度的增大对发光效率的影响则是复杂的。对于上述现象用隧穿理论以及直带模型进行了解释。对制备高亮度, 高效率低损耗的OLED具有指导意义。     

太湖流域不同种浮萍淀粉积累的研究

对在太湖采集的15株浮萍进行分子鉴定,从中筛选出3株高淀粉含量浮萍作为供试材料,对其生长培养基进行优化,并研究饥饿条件对其生长和淀粉积累的影响。结果表明:采集到的浮萍分布于5个种,分别为Lemna aequinoctialis,Lemna minor,Lemna turionfera,Spirodela polyrhiza,Landoltia punctata;与SH培养基相比,改良的培养基SH-1和SH-2均能显著促进浮萍的生长;在饥饿试验中,筛选的3种浮萍S.polyrhizza,L.aequinoctialis和L.punctata每周的生长速率(以鲜重计)分别为18.64,20.77和16.52g/m2,饥饿培养33 d后,淀粉含量分别达到20.6%,21.98%和24.30%,较饥饿前分别增加了73.4%,75.4%和137.5%。相较于S.polyrhiza和L.aequinoctialis,L.punctata在淀粉积累方面表现出一定的优势。     

移动通信基站能耗分析与综合节能解决方案

本文研究了移动通信基站的能耗构成,提出了移动通信基站节能的思路、措施和方案。