C/C复合材料断口热解炭及其界面形貌SEM分析

采用SEM，以增强体为薄毡叠层、基体分别为光滑层及粗糙层结构化学气相沉积热解炭的2种C／C复合材料为研究对象，了三点弯曲试样断口上热解炭及热解炭／热解炭界面的形貌特征，并分析了其成因。结果表明：在垂直于炭纤维轴向的断面上，光滑层结构热解炭未发生塑性变形，但粗糙层结构热解炭发生了明显的塑性变形；在平行于炭纤维轴向的断面上，光滑层结构热解炭／热解炭界面呈光滑状，而粗糙层结构热解炭／热解炭界面呈鳞片状，鳞片的周边粗糙，内部光滑。认为鳞片结构的产生与化学气相沉积过程相关，并对此提出了假设模型：两相邻热解炭生长到界面时，在鳞片周边部位互生长形成真正的结合，使鳞片内部形成封闭的空隙或使气流无法通过鳞片内部，造成鳞片内部的伪结合。     

皮秒激光脉冲触发下光电导开关响应时间的理论计算

本文采用计算机数值分析的方法,分析了激光脉冲的能量、宽度、半导体对光的吸收系数、半导体的表面复合、体复合以及俄歇复合等因素对光电导开关响应时间的影响。结果表明,光电导开关的响应虽然很快,但与光脉冲并不完全同步,而有一个短的时间滞后。     

ROBUST SAMPLED-DATA CONTROL SYSTEMS ANALYSIS BY APPROXIMATE Z-TRANSFORM USING HIGHER-ORDER INTEGRATORS

In this paper, robust sampled-data control systems are analyzed in the frequency domain. Stability analysis of a sampled-data control system using higher-order integrators was proposed by Wang et al. in 1990 [1] and adopted in the approximate Z-transform by Wang et al. in 1997 [2]. We further apply the approximate Z-transform to analyze the stability boundary of a sampled-data control system in which the plant transfer function has bounds prescribed on its parameters.     

非线性MIMO系统线性化解耦的一种新方法(Ⅰ)——连续时间系统

给出用神经网络（ Ｎ Ｎ）α阶积分逆系统实现连续非线性 Ｍ Ｉ Ｍ Ｏ 系统线性化解耦的方法。 Ｎ Ｎα阶积分逆系统由一个静态神经网络加若干积分器构成,将其串联在原系统之前,原系统则解耦成若干个相互无关的 Ｓ Ｉ Ｓ Ｏ 伪线性积分系统。理论分析与仿真结果表明,对于精确模型未知的较一般的非线性 Ｍ Ｉ Ｍ Ｏ 系统,所给出的方法均能实现有效的线性化解耦,且结构简单,易于工程实现。     

Signaling pathway activated during apoptosis of the prostate cancer cell line LNCaP: overexpression of caspase-7 as a new gene therapy strategy for prostate cancer

We studied the molecular mechanisms of apoptosis in the prostate cancer cell line LNCaP and whether overexpression of caspase activity could force this cell line to undergo apoptosis. The inhibitor of phosphomevalonate decarboxylase, sodium phenylacetate, and the protein kinase inhibitor staurosporine induced (a) release of cytochrome c from the mitochondria to the cytosol; (b) reduction in mitochondrial transmembrane potential; (c) proteolytic processing of caspase-3 and -7 but not -2; (d) cleavage of the DEVD substrate and the death substrates poly(ADP-ribose) polymerase and DNA fragmentation factor; and (e) apoptosis. The panspecific inhibitor of caspase activation N-benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethylketone (z-VAD-FMK) prevented all of these events except release of mitochondrial cytochrome c into the cytosol. None of these apoptotic signaling events were elicited by staurosporine or sodium phenylacetate treatment of LNCaP-Bcl-2 cells that overexpress the oncoprotein Bcl-2. Because caspase-7 is activated in every model of apoptosis that we have characterized thus far, we wished to learn whether overexpression of this protease could directly cause apoptosis of LNCaP cells. By using a replication-defective adenovirus, overexpression of caspase-7 protein in both LNCaP and LNCaP-Bcl-2 cells was accompanied by induction of cleavage of the DEVD substrate and TUNEL. These studies have demonstrated that caspase-7 and -3 are critical mediators of apoptosis in LNCaP cells. Caspase-7 was proteolytically activated in every model of apoptosis that we have developed, and the overexpression of it induced apoptosis of LNCaP and LNCaP-Bcl-2 cells. Thus, adenoviral-mediated transfer of caspase-7 may offer a new effective approach for the treatment of prostate cancer.     

一种新型Fresnel波带板

本工作为“神光－Ⅱ”高功率激光聚变实验发展热核带电粒子编码的成像技术,在国内首次研制出无底衬自立式Ｆｒｅｓｎｅｌ波带板,设计组装成编码相机。介绍了该波带板的结构,性能以及它对相干光的衍射实验检验结果。     

一种准连续波雷达中频采样的新方法

在雷达导引头中经常采用高ＰＲＦ倒置接收体制。在这种体制下,目标回波经倒置接收机的窄带滤波器后成为准连续波。因此,采用一种简单的中频采样方法,即可从单路中频信号的采样中获得正交双通道采样的效果。本文首先从原理上对中频采样的主要实现方法进行了综述,然后针对准连续波雷达导引头的特点,提出了一种简单的中频采样方法,其主要特点是以微小的系统误差为代价,大大简化了中频采样的硬件实现方法。最后介绍了客中方法的原理和电路实现的方案、误差来源,并通过实际系统测试证明了理论分析的正确性。     

动目标检测雷达数字信号处理机内建自测试研究

提出了一种动目标检测雷达数字信号处理机内建自测试方法。该方法介于系统级和板级之间,集系统调试、在线测试和离线测试于一体,设计简单,易于实现。论证了处理机各个关键模块的具体测试方法。针对其中的“数据存储重排”模块和“ Ｆ Ｆ Ｔ 与求模”模块,计算了故障覆盖率。     

信息化是中小企业发展的关键

分析了我国中小企业发展的现状及其信息化程度,指出了中小企业信息化的内涵,信息化能提高中小企业的生产力和竞争力。     

产水气井压力恢复特征的新认识

产水气井的压力恢复特征不同于纯气井。根据径向复合储层模型 ,将产水气井压力恢复曲线的上翘特征解释为气、水流度的变化 ,内区为气体流动 ,外区为水流动 ,代替了传统的边界效应解释 ,结合矿场实例 ,说明其适用性