不确定切换系统的动态输出反馈鲁棒H∞控制

研究一类由任意有限多个不确定子系统组成的切换系统的动态输出反馈鲁棒H∞控制问题.利用共同Lyapunov函数方法和凸组合技术,给出由矩阵不等式表示的控制器存在的充分条件,并设计了相应的子控制器和切换规则.采用消元法,将该矩阵不等式转化为一组线性矩阵不等式(LMIs).最后给出一个数值仿真实例证明结论的有效性.研究结果表明:通过切换,闭环系统在整个状态空间上的每个点都满足鲁棒H∞性能,而并不要求每个子系统在整个状态空间上都满足鲁棒H∞性能,甚至也不要求其渐进稳定.     

基于DSP和AVR的嵌入式矿用谐波检测装置的设计

谐波检测是谐波问题的一个重要分支,对能够准确、实时地对电力系统谐波进行检测有着重要的意义.本文介绍了一种基于快速傅里叶的谐波检测方法,并应用其原理设计了一种基于DSP和AVR的新型谐波检测装置,该装置可完成国标规定的电能质量指标的测量,并有数据显示、存储和通信等功能.工程实际测量结果验证了该方案的可行性和可靠性. 关     

Genome-wide association and linkage identify modifier loci of lung disease severity in cystic fibrosis at 11p13 and 20q13.2

A combined genome-wide association and linkage study was used to identify loci causing variation in cystic fibrosis lung disease severity. We identified a significant association (P = 3.34 × 10(-8)) near EHF and APIP (chr11p13) in p.Phe508del homozygotes (n = 1,978). The association replicated in p.Phe508del homozygotes (P = 0.006) from a separate family based study (n = 557), with P = 1.49 × 10(-9) for the three-study joint meta-analysis. Linkage analysis of 486 sibling pairs from the family based study identified a significant quantitative trait locus on chromosome 20q13.2 (log(10) odds = 5.03). Our findings provide insight into the causes of variation in lung disease severity in cystic fibrosis and suggest new therapeutic targets for this life-limiting disorder.     

基于NVH性能的排气系统悬挂点位置设计

基于平均驱动自由度位移（ADDOFD）理论,同时考虑车身侧与排气系统侧的NVH性能,以及各阶模态频率的不同权值的影响,对某车型排气系统吊点位置进行优化布置,并对布置吊点后的排气系统做声学稳健性分析。实际应用表明该设计方法能对汽车排气系统悬挂点选择提供可行性参考建议,在整车开发的初期,有效预测和控制车身结构的NVH性能。     

原发性肝癌组织中TAM和MC与MV计数及病理意义

目的 研究原发性肝癌（primary hepatocarcinoma,PHC）组织中肿瘤相关巨噬细胞（tumor-associated macrophage,TAM）、肥大细胞（mast cells,MC）和微血管（microvessel,MV）的计数及其临床病理意义,并探讨了三者之间的相互关系.方法 应用ABC免疫组化法,对47例PHC手术切除标本常规石蜡包埋切片分别检测TAM、MC和MV,并高倍镜下计数.结果 47例PHC癌组织中TAM、MC和MV计数均显著高于癌旁组织（TAM：70.27±17.93个/HP vs. 44.15±9.10个/HP,P<0.01;MC：15.46±4.54个/HP vs. 8.08±2.03个/HP,P<0.01;MV：67.30±13.68个/HP vs. 37.20±10.58个/HP,P<0.01）;TAM与MV在术前AFU（α-岩藻糖）小于等于10 μg/L病例的计数显著高于AFU大于10 μg/L病例的计数(TAM：74.13±18.33个/HP vs. 61.15±13.54个/HP,P<0.05;MV：70.41±13.03个/HP vs. 59.97±12.69个/HP,P<0.05);伴转移病例癌组织中的MV计数（73.50±13.77个/HP）显著高于无转移病例(64.10±12.68个/HP,P<0.05);MC、TAM、MV在PHC中的计数与PHC其他主要临床病理特征之间均无明显关系;癌组织中TAM计数与MV计数呈正相关（P<0.01,r=0.686）,MC计数与MV计数呈正相关（P<0.05,r=0.348）.结论 MC、TAM、MV的计数与PHC 的发生、发展关系密切;MV计数高的PHC易于发生浸润和转移;TAM、MC与PHC的血管生成可能有密切的关系.     

听觉线索引导大鼠空间定位

运用Morris水迷宫实验模式,研究听觉线索在大鼠进行空间定位时的作用.结果显示:听觉线索引导组和对照组动物在4 d内寻找平台的时间和错误率均显著下降.但与对照组动物相比,听觉线索引导组动物寻找隐藏平台的时间和错误率均较低,2组之间具有显著性差异(P<0.05).对动物的轨迹分析发现,听觉线索引导组和对照组动物在水池边缘区域分配的时间不同,提示2组动物寻找平台所用的策略不同.实验结果提示,大鼠能够利用单独的声音线索进行空间定位.     

Experimental study of heat transfer of ultra-supercritical pressure water in vertical upward internally ribbed tube

Under ultra-supercritical pressure, the heat transfer characteristics of water in vertical upward 4-head internally ribbed tubes with a diameter of 28.65mm and thickness of 8mm were experimentally studied. The experiments were performed at P=25～34MPa, G=450～1800kg/(m2·s) and q=200～600kW/m2. The results show that the pressure has only a moderate effect on the heat transfer of ultra-supercritical water when the water temperature is below the pseudocritical point. Sharp rise of the wall temperature near the pesudocritical region occurs earlier at a higher pressure. Increasing the mass velocity improves the heat transfer with a much stronger effect below the pesudocritical point than that above the pesudocritical point. For given pressure and mass velocity, the inner wall heat flux also shows a significant effect on the inner wall temperature, with a higher inner wall heat flux leading to a higher inner wall temperature. Increasing of inner wall heat flux leads to an early occurrence of sharp rise of the wall temperature. Correlations of heat transfer coefficients are also presented for vertical upward internally ribbed tubes.     

Side-Channel Attacks in a Real Scenario

Existing Side-Channel Attacks(SCAs) have several limitations and, rather than to be real attack methods,can only be considered to be security evaluation methods. Their limitations are mainly related to the sampling conditions, such as the trigger signal embedded in the source code of the encryption device, and the acquisition device that serves as the encryption-device controller. Apart from it being very difficult for an attacker to add a trigger into the original design before making an attack or to control the encryption device, there is a big gap in the capacity of existing SCAs to pose real threats to cipher devices. In this paper, we propose a new method, the sliding window SCA(SW-SCA), which can be applied in scenarios in which the acquisition device is independent of the encryption device and for which the encryption source code requires no trigger signal or modification. First,we describe the main issues in existing SCAs, then we theoretically analyze the effectiveness and complexity of our proposed SW-SCA —a method that can incorporate a sliding-window mechanism into almost all of the existing non-profiled SCAs. The experimental results for both simulated and physical traces verify the effectiveness of the SW-SCA and the appropriateness of its theoretical complexity.     

基于STM32的PID控制程序设计

PID控制是工程领域常用的控制算法。随着嵌入式处理器的不断发展,使用嵌入式设备进行PID控制成为趋势。本文基于STM32微处理器,利用C语言模块化封装性好的优势,设计了直观清晰的PID控制程序。利用积分分离算法改进程序,增强了系统的动态特性,并使用MATLAB对输出的结果进行仿真,证明了程序设计的正确性。     

爆燃压裂技术对水泥试样致裂实验研究

为模拟爆燃压裂技术的破岩效果和裂缝形态,进行了水泥试样致裂实验。制作了含有模拟射孔孔眼的ϕ244.5 mm套管,外维为ϕ1 600 mm×1 000 mm的水泥试样9组,并采用现场常用的航天复合推进剂和军工双基药进行实验。在实验基础上,与层内爆炸技术和重复强电冲击波技术进行储层致裂机理对比分析。研究表明,爆燃压裂技术对9组水泥试样具有100%致裂效果,裂缝条数在2~4条,裂缝缝宽在厘米级,且水泥试样的顶部缝宽要大于中部。随着火药用量减少,井筒内峰值压力减小,岩石裂缝条数减少,裂缝宽度减小。其造缝机理和形态有别于使用炸药的层内爆炸技术和使用脉冲功率负载及含能材料的可重复强电冲击波技术。