复制对象层次表决算法性能分析

根据ＨＱＣ算法的有效性和信息开销，在Ｎｏｖｅｌｌ网络环境下使用模拟方法将该算法对照多数票表决和动态表决作了性能比较。     

FOXBASE计算机辅助教学课件的实现

介绍一个在Ｎｏｖｅｌｌ网上用ＭＦＯＸＢＡＳＥ实现的集教学内容讲解、实验指导、练习训练、试卷测试于一体的计算机辅助ＦＯＸＢＡＳＥ教学系统的设计。     

建构主义教学观与CAI课件制作

在CAI课件制作过程中，很容易形成传统教学模式的简单搬家，失去了CAI课件的真实意义。简要分析当前CAI课件存在的某些不足，在介绍建构主义教学观的基础上，提出CAI课件的制作必须以建构主义为指导，明确CAI课件脚本编写的要求，阐述CAI课件既要适用课堂教学，又要便于学生自学的特点。     

浅谈多媒体教学课件的制作

计算机辅助教学( CAI)系统是由硬件、软件和课件三个基本部分组成.课件是 CAI系统的核心部分,它通过计算机程序实现教学设想、过程、方法和策略等.课件是计算机辅助教学的计划和控制部分,也是教学活动的实施者,课件的好坏直接决定了教学效果的优劣.文章就制作多媒体教学课件中创作工具的选择、开发及制作方法进行了探讨.     

液压与气压传动MCAI课件设计

文章在分析液压与气压传动课程内容及特点的基础上提出了该课程MCAI课件的主要任务及功能，制定了课件的设计原则，根据设计原则完成了课件的结构设计。     

VRML在基于网络的画法几何教学中的应用

针对当前画法几何CAI课件中存在的不足、网络课件相对滞后等缺陷，从画法几何教学的实际需要出发，以课程中的主要内容为教学目标，利用VRML语言的动态性、交互性、基于低带宽网络传输等特性，设计开发了基于网络的画法几何教学课件，介绍了课件的制作和实施的主要技术策略。     

PowerPoint在《工程材料》课件制作中的应用技巧

文中主要介绍工程材料课程在制作教学课件时,如何更好地应用PowerPoint这一多媒体课件制作的常用软件,从几个方面探讨PowerPoint在《工程材料》课件制作中的尝试与应用技巧,以期得到大家的共勉。     

理论力学演示型多媒体课件的研制

从课件研制的指导思想和原则出发,阐述了在中文Ｗｉｎｄｏｗｓ９５环境下,用多媒体创作工具Ａｕｔｈｏｒｗａｒｅ研制理论力学演示型多媒体课件策略和方法,在研制过程中解决的关键技术问题,以及所取得的成果与课件推广前景。     

基于灰色理论的网络课件质量等级评定研究

在分析网络课件特征的基础上，深入剖析了决定网络课件质量的各个要素；引入灰色理论，建立了网络课件质量等级评定模型。构建了灰色理论的评价架构，列出了基于灰色理论的评分矩阵、三角权函数、灰色评价系数、权重矩阵、评价向量矩阵和评价结论值，以对网络课件进行科学的质量等级评定提供依据。     

科学开发网络课件切实提高教学质量

随着社会信息化程度的提高和教育多元化的需求,利用多媒体网络课件实施远程教育已成为高等教育发展的趋势.实施远程教育教学活动必须借助于网络课件.目前,网络课件的开发和建设中还存在着一些问题,迫切需要人们去解决.     

内燃机车非线性振动的隔振研究

对内燃机车的非线性振动的隔振理论进行了研究,给出了隔振效果较好的理论方法。本文所研究的系统是由非弱联系的三个自由度的非线性方程所描述的,因此本文采用的处理方法,在多自由度的非线性振动问题中具有普遍的适用性。     

Lattice-based group signature with verifier-local revocation

Among several post quantum primitives proposed in the past few decades, lattice-based cryptography is considered as the most promising one, due to its underlying rich combinatorial structure, and the worst-case to average-case reductions. The first lattice-based group signature scheme with verifier-local revocation(VLR) is treated as the first quantum-resistant scheme supported member revocation, and was put forward by Langlois et al. This VLR group signature(VLR-GS) has group public key size of O(nm log N log q), and a signature size of O(tm log N log q log β). Nguyen et al. constructed a simple efficient group signature from lattice, with significant advantages in bit-size of both the group public key and the signature. Based on their work, we present a VLR-GS scheme with group public key size of O(nm log q) and signature size of O(tm log q). Our group signature has notable advantages: support of membership revocation, and short in both the public key size and the signature size.     

Tribological behavior of polytetrafluoroethylene coatings based on LY12 substrates in the space environment

The spacecraft space radiation environment was simulated by60 Co source. The polytetrafluoroethylene(PTFE) coatings were fabricated on LY12 substrates. And the effect of gamma(γ) irradiation on the tribological behavior of PTFE coatings under vacuum conditions was investigated. Results indicate that the radiation dose has insignificant effect on the friction coefficient of PTFE coatings, and the wear of PTFE coatings reduces with the increase of gamma dose. As the gamma dose was 100 kGy, the friction coefficient of the PTFE coatings first increased with the increase of sliding velocity and then decreased, and the wear of the PTFE coatings decreased with the increase of sliding speed. As the gamma dose was 100 kGy, the friction coefficient of the PTFE coatings first decreased with the increase of load and then increased, and the wear rate of PTFE coatings increased with the increase of load. Scanning electron microscope was utilized.     

Combustion optimization model for NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> reduction with an improved particle swarm optimization

Abstract: This paper focuses on the combustion optimization to cut down NO _x emission with a new strategy. Firstly, orthogonal experimental design (OED) and chaotic sequences are introduced to improve the performance of particle swarm optimization (PSO). Then, a predicting model for NO _x emission is established on support vector machine (SVM) whose parameters are optimized by the improved PSO. Afterwards, a new optimization model considering coal quantity and air quantity along with the traditional optimization variables is established. At last, the operating parameters are optimized by the improved PSO to cut down the NO _x emission. An application on 600MW unit shows that the new optimization model can cut down NO _x emission effectively and maintain the load balance well. The NO _x emission optimized by the improved PSO is lowest among some state-of-the-art intelligent algorithms. This study can provide important guides for the low NO _x combustion in the power plant.     

Electronic structures and magneto-transport properties of co-based Heusler alloy based magneto-resistance junctions

A direct link between band structure and the ballistic transport property of full-Heusler alloys based Co₂ YZ/Al/Co₂ YZ trilayers (Y = Sc, Ti, V, Cr, Mn and Fe; Z = Al, Si and Ge) has been studied by firstprinciples calculations. It is found that the transport efficiency is determined primarily by three factors related to band structure: the shape of the band crossing Fermi energy E _F, the distance d of the two intersection points of Co₂ YZ and Al at E _F, and the absolute maximum of the energy lying in the E _F-crossing band, |E_max|. The transmission coefficient distribution patterns imply that the affected factor of magneto-resistance (MR) ratio is attributed to the band features around E _F. In general, an intuitively illustrated diagram is proposed to clarify the relationship between the probability of electron transition and the current magnitude.     

Calculation of 3D sensitivity matrix for electromagnetic tomography system using boundary elements and the perturbative approach

Electromagnetic tomography （EMT） is a non-invasive imaging technique capable of mapping the conductivity and permeability of an object. In EMT, eddy currents are induced in the object by the activation coils, and the receiving coils can measure the EMT voltages. When the activation frequency is significantly large, we can treat the metallic targets as electrically perfect conductors （EPCs）. In this situation, a thin skin approximation is reasonable and this type of scattering problem can be effectively treated by the boundary element method （BEM） formulated through integration equations. In this study, we compute three-dimensional （3D） sensitivity matrix between the sensors due to an EPC perturbation. Efficiency improvement is achieved through the utility of scalar magnetic potential. Two EPC objects, one sphere and one cube shaped, are simulated. The results agree well with the H dot H formula. Overall, we conclude that BEM can be used to calculate the 3D sensitivity matrix of an EMT system efficiently. This method is a general one for any shaped objects while the H dot H solution is only capable of producing the response for a small ball.     

Improvement of immunoassay detection sensitivity by using well-defined raspberry-like magnetic microbeads as carriers

Well-defined raspberry-like magnetic microbeads(RMMBs) as immunoassay solid carriers were prepared by chemical covalent binding between Fe3O4 magnetic microspheres and SiO2 nanoparticles. These RMMBs were not as agglomerative as nano-sized magnetie particles( 200 nm), which was an advangtage for high efficient magnetic separation. When compared to Fe3O4@SiO2core-shell magnetic microbeads(CMMBs) with smooth surface, RMMBs exhibited stronger capacity to bind biomolecules. Limit of blank(LoB) and limit of detection(LoD) of HBsAg detection using RMMBs as carriers via chemiluminiscence immunoassay(CLIA) were 0.472 and1.022 μg/L, respectively, showing a notable improvement compared with CMMBs whose LoB and LoD were 1.017 and 1.988 μg/L, respectively. All these indicated a great potential of RMMBs in immunoassay application.     

Polycrystalline behavior analysis of extruded magnesium alloy AZ31

Uniaxial tensile and compressive tests were performed at room temperature on extruded AZ31 Mg alloy specimens and distinct tensile-compressive anisotropy was detected. Deformed specimens were examined and the results indicate that the generation of {10 $\bar 1$ 2}〈10 $\bar 1$ 1〉 twin is responsible for the mechanical anisotropy. A rate independent crystal plasticity model, which accounts for both slip and twinning, was developed for polycrystalline hexagonal close packed (HCP) materials. Model predictions for the stress-strain curves and texture evolution were in reasonable agreement with the experimental results. Specifically, the model captured the three stages of strain hardening for uniaxial-compression. By comparing stress-strain curves and texture evolution between model predictions and experimental measures, information about the dominant slip and twinning systems active at room temperature was deduced.     

Research on Nonlinear Dynamic Simulation and Fatigue Reliability Life Prediction for Synthesis Transmission System of Self-Propelled Gun

Aiming to the puzzle that the inner load of nonlinear synthesis transmission system is difficult to obtain, a new kind of virtual prototype establishment and simulation method is put forward. The influence on nonlinear vibration with flexible rotor, bearing backlash is analyzed based on a virtual prototype. To validate the virtual prototype of nonlinear gear transmission system, the corresponding test platform is established. The consistency between simulation results and test results proves that the simulation results of the virtual prototype can be used to calculate the fatigue reliability life of key components. A new kind of fatigue reliability life prediction method of gear system considering multi-random parameter distribution is put forward based on the fatiguestatistic theory. Considering the periodicity of gear meshing, linear interpolation method is adopted to obtain the stress-time course of random load spectrum based on the gear’s complicated torque provided by virtual prototype. The gear’s P-S_a-S_m-N curved cluster can be simulated based on material’s P-S-N curve. The simulation process considers the parameter distributions of stress concentration coefficients, dimension coefficients and surface quality treatment coefficients, and settles the puzzle that traditional test methods cannot acquire the gear’s fatigue life of all reliability levels. This method can provide the distribution function and the interval of fatigue reliability life of gear’s danger region, and has a guide meaning for the gear maintenance periods determination and reliability evaluation.     

Sliding mode robust fault-tolerant control for uncertain systems with time delay

Considering the modeling uncertainties and external disturbance, a kind of sliding mode robust H∞fault-tolerant control method for time delay system with actuator fault is proposed. The upper-bound of the uncertainties is considered as a known constant, while the upper-bound of the actuator fault is unknown. A sufficient condition for the existence of an integral sliding mode dynamics is given in terms of linear matrix inequality(LMI). A novel adaptive law is given to estimate the unknown upper-bound of faults. On this basis, a type of sliding mode robust H∞fault-tolerant control law is designed to guarantee the asymptotic stability and the H_∞ performance index of the system. Finally, the simulation on quad-rotor semi-physical platform demonstrates the reliability and validity of the method.