基于现场总线的磁浮列车测控系统

本文作者介绍了基于CAN总线和485总线的磁浮列车测控系统。作者详细阐述了磁浮列车测控系统的结构。最后列举了磁浮列车测控系统中系统软件主要的数据结构并叙述了磁浮列车测控系统的系统软件的工作流程。     

椭圆曲线在数字签名中的应用

以椭圆曲线加密系统(ECC)为研究对象，系统地说明了椭圆曲线的数学原理和ECC工作原理，分析了ECC所具有的安全性高、密钥短等技术优势。针对数字签名算法对安全性和速度的技术要求，给出了将ECC应用到数字签名中的实现方法，即椭圆曲线数字签名算法(ECDSA)，ECDSA是具有短签名和短证书的快速签名算法。并以Java为鳊程工具实现了ECDSA。最后提到了ECC在移动通讯和智能卡方面的应用。     

电控汽油机怠速模糊RBF神经网络控制

针对电控汽油机怠速控制要求,提出了一种模糊径向基函数(RBF)神经网络控制方案,在MATLAB环境下进行了控制仿真,获得了比PID、模糊、模糊BP神经网络更好的控制性能。     

基于Mobile Agent技术的安全电子商务系统研究

针对基于Mobile Agent技术的电子商务系统中存在的安全性问题,利用密码学知识以及洋葱路由原理,结合电子商务系统工作特点,以防范主动攻击和被动攻击为前提,提出了一种新的安全性检测协议,给出了该协议的详细实现步骤;并利用该协议和电子商务协商工作原理,设计了基于Mobile Agent技术的安全电子商务系统MASEC,并用Aglets系统对该工作模型进行仿真实验.仿真实验证明:设计的MASEC系统是可行的,降低了人机对话交互的复杂度,提高了电子商务的运作效率.     

轴流式鼓风机静叶承缸事故原因分析

对AV80—14型轴流式鼓风机的静叶承缸受损的原因进行了分析，对受损的静叶承缸的修复过程进行了介绍。通过对事故承缸进行变形校正和裂纹修复，使受损静叶承缸起死回生，节约备件购置费用200万元以上。     

C/C复合材料烧蚀性能的研究进展

C／C复合材料是一种良好的抗烧蚀和耐高温结构材料,广泛地应用于航天航空各领域。在此,作者综述了C／C复合材料烧蚀性能的测试方法、烧蚀机理、烧蚀模型以及抗烧蚀的研究状况。     

Least-Squares, Moment-Based, and Hybrid Polynomializations of Drag Forces

In order to carry out nonlinear dynamic analyses of fixed offshore structures in the frequency domain, polynomial approximations of the distributed drag term, u∣u∣, and inundation drag term, ηu∣u∣, of the Morison forces are studied. The methods of least-squares and moment-based approximations are considered for cases with and without current. Numerical results and analytical expressions of the polynomial coefficients are presented for the cubic approximations of u∣u∣ and quartic approximations of ηu∣u∣. The curve shapes, first four central moments, and probability density functions of the different approximations are evaluated and compared with the corresponding exact solutions. For the nonmonotonic inundation drag term with the current effect included, a hybrid polynomialization, based on the least-squares approximation for the odd-order polynomial coefficients and the moment-based approximation for the even-order coefficients, is proposed.     

我国电信管制现状述评

经过近几年的电信改革，我国电信市场竞争格局初步形成，但与国外相对比较成熟的市场相比还存在诸多问题，例如目前规范行业健康发展的必要法律、法规极不健全，电信市场竞争还处于建立行业规范、明确竞争规则的初级阶段，表现为恶性价格战和互联互通冲突时有发生；电信业固有的特     

Effects of Magnetic Heat Treatment on Magnetostiction Properties of Tb0.3 Dy0.7 Fe1.95 Alloy

The effects of magnetic heat treatment on magnetostriction properties of Tb0.3Dy0.7Fe1.95 alloy were investigated.The directionally solidified alloy was heated to various temperatures near Curie temperature TC in vacuum, kept for a certain time under the application of magnetic field and then cooled to room temperature.The magnetostriction coefficient was measured by a resistance strain gage.The crystal structure was analyzed by X-ray diffraction (XRD).The experimental results show that the magnetostriction coefficient obviously increases and the grains orientations along the axis changed somewhat as the field of 1 T vertical to axis of the rod-shaped specimen is applied for 5 min at the heating temperature slightly lower than TC.     

Study on Copolymer of PMMA with Eu Complex

The europium complex, Eu3 -1,10-phenanthroline (Phen) -acrylic acid (AA) was prepared and its structural formula is Eu(Phen) (AA)3. The high luminescence rare earth polymer materials were obtained by the copolymerization of europium complex with methyl methacrylate using AIBN as an initiator. The copolymer structure and properties were characterized by FT-IR, UV-Vis, RF spectra and thermogravimetric analysis (TG). Results indicate that block copolymer is synthesized. Fluorescent property shows that Eu copolymer emits rare earth fluorescence and the emission intensity increases with the rise in Eu content and reaches a maximum value.