准正交矩阵与准对称矩阵

利用次转置阵给出了准正交阵与(反)准对称阵的概念;研究了它们的基本性质及其之间的联系;取得了许多新的结果,推广丫正交阵、对称阵与反对称阵间的相应结果,特别将正交阵的广义Cayley分解推广到了准正交阵上;将各类正交阵、对称阵及广义逆矩阵统一了起来。     

旋转导弹横向喷流/超声速来流干扰数值模拟

以旋转坐标系下Navier- Stokes方程为控制方程，用有限体积法、对称TVD格式和重叠网格技术对带有单股和两股横向喷流旋转导弹的喷流干扰流场进行了数值模拟，计算了喷流与来流、喷流与喷流之间的干扰情况。结果表明：两股喷流增强了与来流之间的干扰，喷流与喷流间也存在干扰；两种干扰影响使力放大因子较单股喷流高；旋转使喷口前的分离区形状改变；在背风面喷流时，旋转使喷流羽流发生周向偏转，影响喷流干扰力放大因子。     

一般球对称荷电时空的KKW分析

Vagenas等人运用KKW分析方法对一般球对称时空进行了研究,后来此方法也应用于二维荷电时空和自引力反作用的高阶效应等方面的研究.这里与Vagenas等人的研究不同,考虑了能量守恒和电荷守恒,延伸和发展了KKW分析,应用于一般球对称荷电时空,并给出了此类时空的修正熵和温度.     

Fundamental Uncertainty Rotationally Symmetric and Anamorphic Laser Triangulation

Rotationally symmetric triangulation （RST） sensor is one of the newest developments in laser distance measurement. Speckle is also the fundamental uncertainty factor in this kind of sensors. A detailed analysis of centroid uncertainty in RST is presented in this paper. The analytic expression of centroid uncertainty limit when measuring an optical rough surface is derived. It is shown that the uncertainty limit in RST, and also in anamorphic triangulation, is dependent on the solid angle subtended by entrance pupil as seen from the illuminated laser spot, as well as the laser wavelength. Results of simulation and experiments verify the deriving. The uncertainty limit in RST is about 1/5 of the one in traditional triangulation with same numerical aperture and triangulation angel. It＇s also analysed how the aberration of the optical system influence the uncertainty limit.     

Forward, backward, and symmetric solutions of discrete ARMA representations

The main objective of this paper is to determine a closed formula for the forward, backward, and symmetric solution of a general discrete-time Autoregressive Moving Average representation. The importance of this formula is that it is easily implemented in a computer algorithm and gives rise to the solution of analysis, synthesis, and design problems.     

Numerical Simulation of Deflecting Flow in a Symmetric Enlarged Channel

Numerical results of three-dimensional separated flow and heat transfer in a rectangular channel with a suddenexpansion are presented in this paper.Numerical simulations of Navier-Stokes and energy equations are carriedout using the finite difference method.The results of three-dimensional calculations are compared with thetwo-dimensional ones,and effects of the aspect ratio of channel upon the flow are shown.The transition fromsymmetric to asymmetric flow appears at lower Reynolds number as increasing the aspect ratio.The details oflocal heat transfer characteristics in two different separated flow regions on two downstream walls are clarified.Two-dimensionality of the flow and heat transfer almost disappears for the aspect ratio considered.     

SCADA系统在苏丹油田上的应用

剖析了应用在苏丹油田上的SCADA系统的原理和构成,描述了网络技术在SCADA系统中的应用,并着重对SCADA系统的RTU子系统——1/2/4区块中心处理站CPF进行了硬件和软件的结构和系统分析。     

基于决策树的电力系统实时动态安全评估方法研究

电力需求增长和电力市场管制的压力下,电力系统必须通过缩小运行安全裕度,以使其运行接近稳定极限,为系统实时安全指标提供充足的时间进行分析、决策和准确地实施补救控制,提出了一种对称不确定性(SU)算法和逻辑模型树(LMT)算法分别作为特征选择的高级分类器和决策树分类器,该方法利用对称不确定性(SU)来降低基于决策树分类器的动态安全评估(DSA)工具中的数据冗余。结果表明,SU显著降低了DSA数据集的维数,对于改进的IEEE 30总线测试系统模型的DSA,SU算法可以减少30.76%的计算时间,而LMT算法的精度可以提高到100%,同时提高了决策树分类器的性能。基于SU的决策树分类器能够近实时地评估系统的动态安全性。该方法对电力系统实时保护和控制应用具有一定的参考价值。     

含氧酸的氧化性与球形对称结构

提出了最高氧化态含氧酸氧化性与其中心离了电子分布偏离球形对称结构有关以及相关的假设，解释了各周期系元素最高氧化态含氧酸或酸酐氧化性的规律。该观战可推广使用。     

一种管道动力学建模的新方法

管道是在生活中应用非常普遍的结构之一。一般情况下,管道作为传输物质的通道连接着各种大型仪器或设备。管道的振动不仅会影响到管道内部传输物质的效率,严重时会导致物质泄漏和设备损坏等灾难性的后果。首先阐述针对管系进行动力学建模的常用方法,分析得出现有方法的局限性,然后引入以轴对称矩形模型为基础的管道动力学建模方法,最后通过一段管道仿真计算得出该方法与现有方法之间的差异,证明了该方法的可行性和实用性。