Windows和Linux环境下的用户身份统一管理

在一个包含了Windows／UNIX／Linux系统的大型内部网络中，利用活动目录服务、网络信息服务以及活动目录服务和网络信息服务集成技术，实现Windows／UNIX／Linux系统的帐户、口令的统一配置管理，降低系统管理成本。     

基于脉冲控制下的复杂时滞动力网络的鲁棒同步

近年来复杂网络已经引起了科学和工程技术等各个领域的广泛关注,尤其是复杂网络中的非线性动力学行为,以及网络的拓扑结构如何影响它的动力学行为的研究,已成为当前一项极其重要的战略课题.本文主要讨论基于脉冲控制下复杂时滞动力网络的同步动力学,应用时滞动力系统的脉冲控制理论,给出了复杂时滞动力网络的一些简单而又一般的鲁棒同步化准则,这些准则能够提供一个新的和有效的控制方法来同步一个任意给定的时滞动力网络到一个期望的同步态,进一步地将所获得的结果应用到由混沌FHN神经元振子为动力节点所构成的一个具有近邻耦合结构的复杂动力网络,数值模拟表明了所获理论结果的正确性和控制方法的有效性.     

复杂动态网络传播动力学

病毒、谣言、舆论等在现实社会中各种复杂网络系统上的传播现象与人们现代社会经济生活息息相关,对复杂网络上各种传播现象的动力学行为研究是复杂网络理论的一个重要命题.从流行病学的角度, 针对复杂网络传播行为中存在的动态过程,从自适应躲避、响应时滞、离散采样、开放式系统增长等方面综述了复杂网络传播动力学研究的若干进展.      

结构紧固连接件损伤的神经网络诊断研究

在结构紧固连接件损伤诊断中采用了函数连接型神经网络。与常用的ＢＰ网络不同，函数连接网络通过对输入模式的增强来实现复杂模式的分类。它借助某种函数变换，将原始的模式特征向量变换成另一个更高维的形式，使原始空间里不能区分的类别，在这个高维空间中得以区分，减少了神经网络的层数，提高了网络的学习速度。诊断时选用正弦激振下结构中多个位置上传感器稳态响应的幅值构成表征损伤的特征向量，简化了特征提取的过程。数值模拟和实验结果表明，这一方法能对多个位置的损伤进行准确的识别     

基于LSTM-GAN的无人机飞行数据异常检测算法

飞行数据的异常检测是保障无人机飞行安全的关键。为了提升异常检测的准确率,以更好地构建无人机飞行数据正常样本的数据模式,提出了一种基于长短时记忆网络（LSTM）和生成对抗网络（GAN）的异常检测算法。设计了由生成网络、判别网络和重构网络组成的循环学习网络,同时为了避免网络学习产生梯度爆炸的风险,设计了一种由两个判别损失函数与一个重构损失函数相结合的目标损失函数。实验结果表明,LSTM-GAN异常检测算法均优于K-means、单类支持向量机、LSTM和Auto-Encoder算法的异常检测性能。LSTM-GAN比LSTM异常检测的准确率提高2.2%。     

阵发型神经元网络的联想记忆与分割

以Hindmarsh-Rose(HR)神经元组成网络,研究这些网络的记忆(或模式)存储与时间分割问题．给定一个输入模式,它是几种模式的叠加,网络能够以一部分神经元同步发放的形式一个接一个地分割出每一种模式．如果输入的模式是缺损的,系统能够恢复为原型,即网络具有联想记忆功能．模拟也得到据作者所知至今还未报道的一些现象．     

孔隙网络模型在渗流力学研究中的应用

孔隙网络模型广泛地用于同多孔介质有关的微观模拟中. 本文简介了利用网络模型研究储层渗流规律的基本思想、主要步骤以及网络模型同其它微观模型相比较的优缺点, 总结了在微观渗流研究中使用的两大类网络模型(准静态网络模型和动态网络模型)的特征及其适用范围, 综述了目前网络模型在研究渗流中的应用现状以及国内外研究比较活跃的几个方面,最后分析了网络模型今后的发展趋向.      

400路程控网络讯号源

网络讯号源是大型爆轰多点测试技术中的一个重要组成部分。主要介绍４００路程网络讯号源的设计要点、工作原理和系统结构，并对它在爆轰实验中的测试应用进行了讨论。     

岩体裂隙网络分数维计算机模拟

岩体裂隙网络的研究是一个方兴未艾的课题,而用分形几何来研究岩体裂隙网络是一种行之有效的手段,本文将介绍由笔者编制的计算机裂隙网络分数维求解方法及程序,以达到快速、便捷而又准确地求解复杂网络的分维数。     

神经网络动力系统吸引子对称性的变化

用余维２的双Ｈｏｐｆ分叉的规范形方程设计了期望存储振荡型记忆模式的模拟四阶关系神经网络，所设计的网络向量场具有中心对称性。研究表明该网络发生二阶双Ｈｏｐｆ分叉后可以出现不变二环面。观察二环面上的销相运动，发现了系统出现对称破裂的规律，邓把双Ｈｏｐｆ分叉的两个频率比表示成既约分数的形式，当该分数的分子和分母均为奇数时，网络的吸引子保持对称性，而当分子主分母中任一个为偶数时，就会发生对称破裂。     

再生骨料透水混凝土抗压性能及透水性能试验研究

通过掺30%再生骨料和未掺再生骨料两种透水混凝土的抗压性能及透水性能对比试验,研究了水灰比、骨料粒径、砂率等因素对其抗压性能和透水性能的影响,确定了按体积法配制的合理性和最佳配合比。试验结果表明,采用5~10mm的骨料粒径、水灰比为0.3和目标孔隙率为15%时,掺30%再生骨料和未掺再生骨料两种透水混凝土抗压强度分别达到18.0MPa和19.2MPa,且透水系数均大于5mm/s。基于上述试验结果,分析了掺30%再生骨料和未掺再生骨料两种透水混凝土孔隙率与透水系数及抗压强度之间的关系,表明它们之间存在着相关性良好的函数关系,即可以通过调整孔隙率的大小来平衡抗压强度与透水系数,使之均满足实际工程要求。     

非饱和粘性土中气体渗透特征

由于气体的进入形成了非饱和带,饱和土层中的气体渗透实质上是非饱和渗透问题。本文借助基于多孔介质气体渗流理论并考虑气体压缩性的、描述非饱和土中气体渗流运动的本构方程,试验研究了上海地区饱和粘性土层中的气体渗透规律。结果表明,饱水粘性土层中,气体渗透存在起始压力值,数值为100～200kPa, 与上海地区粘土的非饱和进气值较为接近;气体渗透速度与外界所施加的"压力平方差梯度"之间存在明显的分段特征。后者可能与在充满结合水的微孔隙通道中,只有一部分结合水在气压梯度的作用下发生流动,从而形成气体通道,施加的外力越大,形成的气体通道也越大,气体渗流也越明显。非饱和粘性土中气体渗透规律的研究,对于饱和粘土中的气压法施工,具有重要的理论与工程实践意义。     

Characterization of gold/PMMA hybrid nanomaterials synthesized by hard X-ray synchrotron radiation

In this study,new types of hybrid gold poly(methyl methacrylate) (PMMA) nanomaterials are synthesized.Both PMMA spheres coated with gold nanoparticles and gold nanoparticles coated with PMMA can be synthesized using different ratios of HAuCl4 and MMA precursors,by exposing the mixtures to hard X-ray synchrotron radiation without the use of a reducing agent.According to the photochemical mechanism,gold nanoparticles will precipitate from a solution of HAuCl4 on exposure to synchrotron radiation,followed by the synthesis of PMMA by the polymerization of MMA monomers.These reactions can result in the formation of two different types of new hybrid nanomaterials.When a 1:1 volume ratio of HAuCl4 to MMA is used,we obtain PMMA spheres coated with gold nanoparticles.When a 10:1 ratio of HAuCl4 and MMA is used,we obtain gold nanoparticles coated with PMMA.The hybrid gold/PMMA nanostructures are characterized by transmission electron microscopy,elemental analysis,dynamic-light scattering analysis,gel permeation chromatography and Raman spectroscopy.The hybrid nanomateriais have potential application in the fields of biosensors and drug delivery.     

Dispersion of particles in wall-bounded particle-laden turbulent flows with high wall permeability

A series of numerical simulations were performed to investigate the distribution and deposition properties of particles in turbulent flows bounded by permeable walls using the Large Eddy Simulation (LES) with a Lagrangian trajectory approach. The wall permeation speeds were taken from 10⁻⁴ to 10⁻² of the bulk velocity. The directions of the permeation speed were the same at both walls, and they were inward on one wall but outward on the other wall to reserve the fluid mass. Particles with Stokes number (respecting viscous time scale) around 0.1, 1 and 10 were released in the fully developed turbulent channel flow. The particle–particle interaction and the retroaction from particles to the fluid were neglected. The fluid-phase turbulence statistical properties and particle's transport characteristics by vortexes were then analyzed in details. If the wall permeation exists, the turbulence intensities will be depressed close to the outward permeable wall but increased near the inward permeable wall. Not influenced by the wall permeation, the suspended particles with St⁺ ∼O(1) tend to accumulate in the less vortical zones away from the wall, while those particles in the flow regions near the outward permeable wall will distribute disregarding of the vorticity. The turbulence structures near the outward permeable wall are found to exert promotional effects on the particle deposition rate, but such effects are different for particles with various Stokes number. A distribution tendency of streamwise streaks for the deposited particles is also found on the wall imposed by the high outward permeation speed and the clustering deposition pattern is more obvious with increasing particle Stokes number.     

Characterization of gold]PMMA hybrid nanomaterials synthesized by hard X-ray synchrotron radiation

In this study, new types of hybrid gold poly（methyl methacrylate） （PMMA） nanomaterials are synthesized. Both PMMA spheres coated with gold nanoparticles and gold nanoparticles coated with PMMA can be synthesized using different ratios of HAuCl4 and MMA precursors, by exposing the mixtures to hard X-ray synchrotron radiation without the use of a reducing agent. According to the photochemical mechanism, gold nanoparticles will precipitate from a solution of HAuCl4 on exposure to synchrotron radiation, followed by the synthesis of PMMA by the polymerization of MMA monomers. These reactions can result in the formation of two different types of new hybrid nanomaterials. When a 1：1 volume ratio of HAuCI4 to MMA is used, we obtain PMMA spheres coated with gold nanoparticles. When a 10：1 ratio of HAuCl4 and MMA is used, we obtain gold nanoparticles coated with PMMA. The hybrid gold/PMMA nanostructures are characterized by transmission electron microscopy, elemental analysis, dynamic-light scattering analysis, gel permeation chromatography and Raman spectroscopy. The hybrid nanomaterials have potential application in the fields of biosensors and drug delivery.     

Surface Patterning Increases Fluid Sorption Efficiency in Porous Reactive Coatings: A Model for Optimised Surface-Flow Filtration

Transport in Porous Media - A novel surface-flow filter has been designed to take advantage of a combination of both diffusion and lateral flow permeation, since active coatings, even if porous,...     

An Experimental Study on the Effects of Water Content on Coalbed Gas Permeability in Ground Stress Fields

Experimental coal cores were collected from a coalbed of Sihe colliery and Zhaozhuang colliery, Qinshui Basin, China. Their gas effective permeability was studied under effects of water content and effective stress. The experiments were mainly carried out on a self-made ??Triaxial Stress Thermal?Chydrological?Cmechanical Coal Gas Permeameter.?? The results showed that when the temperatures of gas and coal were constant, a negative effect of either water content or effective stress was reported on the gas transportation, i.e., the gas effective permeability decreased with the increasing of water content under constant effective stress and it also decreased as the effective stress increased when the water content was constant. Under experimental conditions as in this study, the effects of water content and effective stress on the gas effective permeability was described by a linear?Cexponential equation, which presented that the gas effective permeability had a linear relationship with the water content and an exponential relationship with the effective stress. The permeation pores were defined as the primary places of transporting the coalbed gas. They were affected by water content and effective stress in different ways. The water content occupied the space of permeation pores, while the effective stress changed the shape of permeation pores. Consequently, the gas effective permeability was also affected by the two aspects.     

Two-phase displacement of non-newtonian fluid

This paper considers the problem of non-Newtonian oil displa-cement by water in porous media.adopting the linear permea-tion law with initial pressure gradient.For one-dimensionalflow,the basic equation of non-Newtonian oil displacement bywater in sandstone reservoirs and fractured reservoirs is de-rived and numerical solutions are obtained.The results arecompared with the corresponding ones for Newtonian oil dis-placement to show the essential characteristics of non-Newto-nian oil displacement by water.     

Parallel arithmetic numerical simulation and application of secondary migration-accumulation of oil resources

From such actual conditions as the effects of characteristics of miltilayer petroleum geology and permeation fluid mechanics, a new numerical model is put forward and coupling splitting-up implicit interactive scheme is formed. For the actual situation of Dongying hollow ( four-layer ) and Tanhai region ( three-layer ) of Shengli Petroleum Field, the numerical simulation test results and the actual conditions are coincident.     

碳钢表面渗硼层在油润滑条件下的摩擦磨损性能研究

采用化学热处理工艺对 45 # 钢进行渗硼表面改性 .在 SRV摩擦磨损试验机上对比考察了渗硼层在液体石蜡及含硼添加剂 -液体石蜡润滑下的摩擦磨损性能 .采用 X射线光电子能谱仪和 X射线衍射仪对比分析了 45 #钢表面硼改性层和含硼添加剂润滑下钢球磨斑表面典型元素组成和化学状态 .结果表明 ,化学渗硼可以大幅度降低碳钢的摩擦系数和磨损体积损失 ,渗硼层主要由 Fe2 B和 B2 O3 组成 ;渗硼改性层在含硼添加剂 /液体石蜡润滑下的摩擦磨损性能进一步改善 ,这归因于渗硼改性和含硼添加剂的摩擦化学效应的双重作用