基于LabVIEW与Multisim的火控系统半实物联合仿真方法

针对当前装甲装备火控系统电路组成与功能特点,对火控系统维修保养过程中的故障诊断方法与测试需求进行了研究,提出了一种火控系统半实物联合仿真方法,介绍了该仿真建模方法的设计思路与实现方法。该方法可充分发挥LabVIEW和Multisim软件的优势,通过半实物联合仿真的方法,以仿真模型代替部分或者全部火控系统部组件,能够很好地实现火控系统不同级别的电路功能模拟、故障复现,快速完成故障诊断分析,解决了当前装甲装备火控系统维修诊断设备通用性差、规范化程度低、开放性差,难以真实的模拟系统级、部件级功能、故障注入和故障检测等问题,为装甲装备火控系统故障诊断与测试设备开发提供了有效平台,为基层部队开展维修训练和维护保障提供了有效途径。     

关于子群的两种广义正规性的注记

群 G 的一个子群 H 称为在 G 中具有半覆盖远离性,如果存在 G 的一个主群列1=G_0＜ G_1＜…＜G_1=G,使得对每一 i=1,…,l 或者 H 覆盖 G_j/G_(j-1)或者 H 远离 G_j/G_(j-1)．本文证明了予群的半覆盖远离性是子群 C-正规性和子群的覆盖远离性之推广．进一步应用极大子群和 Sylow 子群给出了有限群为可解群的一些特征．     

The simulation of inviscid,compressible flows using an upwind kinetic method on unstructured grids

A kinetic flux-vector-splitting method has been used to solve the Euler equations for inviscid, compressible flow on unstructured grids. This method is derived from the Boltzmann equation and is an upwind, cell-centered, finite volume scheme with an explicit time-stepping procedure. The Delaunay triangulation has been used to generate the grids. The approach is demonstrated for three flow field simulations, namely the subsonic flow over a two-component high-lift aerofoil, the transonic flow over an aerofoil and the supersonic flow in a channel.     

高光谱数据基于流形的半监督特征选择

传统的高光谱数据特征选择方法分为监督和无监督模式,然而在高光谱数据实际处理中,大量无标记和少量有标记数据并存.此外,传统方法忽视了真实数据嵌入在高维空间中的流形结构.本文提出一种基于流形的半监督特征选择算法,定义一个合理的特征评判准则,考虑标记样本的先验信息以及高维数据局部和非局部结构的不变特性.通过对标记数据类间方差和类内方差的极大化和极小化,优化数据的判别结构;同时通过构建局部graph和非局部graph,挖掘高维数据的流形结构.然后,选择一组有效的特征子集,实现高维数据的特征选择.最后,通过对特征选择后的真实高光谱数据进行分类实验,结果显示本文方法可以很好地对高光谱数据实现降维并且保留数据的主要结构.     

Synchronization of spatiotemporal semiconductor lasers and its application in color image encryption

Optical chaos is a topic of current research characterized by high-dimensional nonlinearity which is attributed to the delay-induced dynamics, high bandwidth and easy modular implementation of optical feedback. In light of these facts, which add enough confusion and diffusion properties for secure communications, we explore the synchronization phenomena in spatiotemporal semiconductor laser systems. The novel system is used in a two-phase colored image encryption process. The high-dimensional chaotic attractor generated by the system produces a completely randomized chaotic time series, which is ideal in the secure encoding of messages. The scheme thus illustrated is a two-phase encryption method, which provides sufficiently high confusion and diffusion properties of chaotic cryptosystem employed with unique data sets of processed chaotic sequences. In this novel method of cryptography, the chaotic phase masks are represented as images using the chaotic sequences as the elements of the image. The scheme drastically permutes the positions of the picture elements. The next additional layer of security further alters the statistical information of the original image to a great extent along the three-color planes. The intermediate results during encryption demonstrate the infeasibility for an unauthorized user to decipher the cipher image. Exhaustive statistical tests conducted validate that the scheme is robust against noise and resistant to common attacks due to the double shield of encryption and the infinite dimensionality of the relevant system of partial differential equations.     

On L-Tychonoff spaces II

This paper is a sequel to the 1995 paper On L-Tychonoff spaces. The embedding theorem for L-topological spaces is shown to hold true for L an arbitrary complete lattice without imposing any order reversing involution (·)^′ on L. Some results on completely L-regular spaces and on L-Tychonoff spaces, which have previously been known to hold true for (L,^′) a frame, are exhibited as ones holding for (L,^′) a meet-continuous lattice. For such a lattice an insertion theorem for completely L-regular spaces is given. Some weak forms of separating families of maps are discussed. We also clarify the dependence between the sub-T₀ separation axiom of Liu and the L-T₀ separation axiom of Rodabaugh.     

A comparison between neural network method and semi empirical equations to predict the solubility of different compounds in supercritical carbon dioxide

Accuracy of seven semi empirical equations for the estimation of solubility of 30 different compounds in supercritical carbon dioxide has been compared with a new neural network method. To base this comparison on a fair basis, a unique set of experimental data was used for both optimization of semi empirical equations’ parameters and training, validation and testing of neural network. Results showed that neural network method with an average relative deviation of about 5.3% was more accurate than the best semi empirical equation with an average relative deviation of about 15.96% for same compounds. It was also found that the average relative deviation of semi empirical equations varies sharply among different compounds, while this quantity is less dependent on material type for neural network method.     

Synthesis of novel 1,4-disubstituted-1,2,3-triazole semi synthetic analogues of forskolin by click reaction

New 1,4-disubstituted-1,2,3-triazole analogues of forskolin (5a-g, 6a-g) have been prepared by regioselective propargylation at 1-position followed by Cu(I) catalysed cycloaddition of different alkyl azides under the click reaction conditions. An interesting acyl shift in the base catalysed propargylation afforded a new series of 1,4-disubstituted-1,2,3-triazole analogues of forskolin (6a-g). These analogues have potential selective therapeutic applications as antihypertensive, antiglaucoma, antiasthma and antiobesity agents.