基于视域剔除和图像缓存技术的复杂场景快速绘制方法

结合基于场景图构建的虚拟场景和仿真应用的特点,提出了一种基于视域剔除和图像缓存技术的复杂场景快速绘制方法。此方法能够有效地解决图像缓存算法中,由于未考虑视域不可见剔除,而造成的绘制元素复杂度计算偏差引起图像缓存误判断,从而降低绘制效率的问题。另外,通过对图像缓存有效性的判断,可以简化视域不可见剔除的判断,提高绘制效率。     

相邻k-out-of-n:F多状态可修系统的可靠性分析

针对相邻k-out-of-n:F多状态可修系统可靠性指标计算难的问题,提出了两种求解该系统可靠性指标的方法。当系统部件寿命和修理时间都服从指数分布时,方法一首先利用马尔可夫过程理论获得部件的可用度,再用部件的可用度获得系统的瞬态、稳态可用度;方法二针对状态空间巨大的情况,先以一定的标准对状态空间进行截尾,再应用马尔可夫模型获得系统的稳态可用度、首次故障前平均时间、稳态故障频度等可靠性指标。最后通过数值算例说明了所提出方法的有效性。     

基于神经网络的布图设计产业化前景评估

给出了集成电路布图设计产业化前景的评价指标体系,并通过构建前馈神经网络专家系统,对集成电路布图设计的产业化前景进行综合分析。该指标体系和专家系统较好地解决了对集成电路布图设计的产业化前景进行综合分析的问题。选择17个集成电路布图进行了实例分析,对比分析的结果表明该系统具有强大的计算与学习能力,能迅速快捷地判断布图设计的产业前景。     

加强民主管理 推进企业和谐发展

论述新形势下,民主管理在企业长远发展中的重要作用,以自身具体的工作实践为例,介绍了加强民主管理的措施,提高职工素质的渠道及其他重要举措。     

纤维增强陶瓷基复合材料与金属钎焊研究进展

纤维增强陶瓷基复合材料在高温使役性能方面表现出超越传统陶瓷材料的优异性能，与金属的连接构件在航空航天、核能、化工等高温系统中应用潜力巨大。纤维增强陶瓷基复合材料与金属的连接技术被广泛研究，钎焊是实现二者连接的最佳选择。文章重点论述钎焊纤维增强陶瓷基复合材料与金属所面临的挑战和科学问题，列举C_f/C、C_f/SiC和SiO_2f/SiO₂三种研究最为广泛的纤维增强陶瓷基复合材料与金属的钎焊实例，讨论钎料润湿行为、界面反应调控和接头应力调节的最新研究成果。可靠连接技术的发展，将会推动纤维增强陶瓷基复合材料的研究和应用。     

张衡地动仪的科学复原

研究工作遵循“原理正确，结构合理，造型有据，逼近历史”的原则开展。介绍了科学复原模型应满足的6个条件，以及在史料研究、地震学研究、试验研究三方面取得的新结果。新模型的工作原理是悬垂摆，内部结构有五部分，形似汉代温酒尊，蟾蜍为器足，更加符合史料和汉代的历史特征。原大框架结构已经具有良好的验震和抗干扰功能，陇西地震现象得到重现，实现了从概念模型到科学仪器复原的历史跨越。目前，1／3原大的外型与结构小样已在河南博物院和北京海淀公共安全馆正式展出。     

构建具有创新精神与实践能力的人才培养体系

构建创造型人才培养体系,需要改变教育观念,全面推进素质教育;重构教师培养体制;改革教师分配制度,形成激励机制;加大投入力度,扩大创新型人才培养的覆盖面;改革实验室建设和管理模式,不断探索培养创造型人才的有效途径。     

Implementing Operating System Support for Extended Trusted Path in TPM-Capable Environments

Trusted path is one of the crucial features that operating systems must provide for fundamental security support. In order to explore the possibility of implementing a trusted path mechanism with the support of trusted platform module （TPM） technologies, and to support TPM capabilities in operating systems, the paper extended the scope of the conventional trusted path to cover the situation in which a user communicates with software residing on a remote host. The paper combined the concept of operating system support for trusted path with that for TPM platforms, and proposed the architecture of an extended trusted path mechanism in operating system with considerations on TPM-capable platforms support. As part of the author＇s research in secure operating systems, the work of the paper was carried out with Linux as an experimental prototype system. The research result shows that TPM capabilities can strengthen extended trusted path mechanisms of operating systems.     

Numerical investigation on the self-excited oscillation of wet steam flow in a supersonic turbine cascade

The self-excited flow oscillation due to supercritical heat addition during the condensation process in wet steam turbine is an important issue. With an Eulerian/Eulerian model, the self-excited oscillation of wet steam flow in a supersonic turbine cascade is investigated. A proper inlet supercooling results in the transition from steady flow to self-excited oscillating flow in the cascade of steam turbine. The frequency dependency on the inlet supercooling is not monotonic. The flow oscillation leads to non-synchronous periodical variation of the inlet and outlet mass flow rate. The aerodynamic force on the blade varies periodically due to the self-excited flow oscillation. With the frequency lies between 18.1?80.64 Hz, the oscillating flow is apt to act with the periodical variation of the inlet supercooling due to stator rotor interaction in a syntonic pattern, and results in larger aerodynamic force on the blade. The loss in the oscillating flow increases 20.64% compared with that in the steady flow.     

动态电压恢复器的控制策略

通过把负载电压看作动态电压恢复器(DVR)的控制对象,开关器件的占空比看作控制量,电网电压和负载电流看作干扰量,可将DVR的数学模型简化为单输入单输出系统.结合控制量的计算方法,推导出了控制量到被控对象和干扰量到被控对象的传递函数.分析传递函数可知,负载电流特别是其中的高频分量会使DVR的补偿性能变坏.提出了误差校正控制方法,在传统电网电压前馈的基础上通过误差校正实现了负载电流前馈,基本消除了负载电流的影响.仿真结果验证了理论分析的正确性.