Mechanical properties and residue stress of four kinds of ZrC coatings prepared by chemical vapor deposition

Four kinds of ZrC coatings with nearly the same thickness have been successfully prepared on graphite substrate by chemical vapor deposition (CVD) through controlling the ratio of inlet reacting gases. From backscattered electron images, it can be inferred that ZrCIII coating has the best tightness of all coatings. Meanwhile, line energy spectrum curve shows that zirconium and carbon elements distribute uniformly along the normal direction of the ZrCIII coating. As for varied microstructures, the coatings show different mechanical properties and residue stress. The strength and elastic modulus of ZrCIII coating were up to 89.57 and 1 192.5GPa, respectively. Those make it near the level of diamond. Value of residue tensile stress of ZrC+C composite coating was only 7.729MPa and that of ZrCIII coatings was 349.632 MPa. The strong combination of small-size grains in ZrCIII coating plays a decisive role to the best mechanical properties. However, strong misfit of lattice between ZrCIII coating and substrate can induce high residue stress.     

Preparation and Characterization of a Novel Hybrid Copolymer Hydrogel with Poly（ethylene glycol） Dimethacrylate, 2-Hydroxyethyl Methacrylate and Layered Double Hydroxides

This paper describes the fabrication, characterization and properties of a novel hybrid poly(ethylene glycol) (PEG) based hydrogel via in situ polymerization. The hybrid hydrogel was fabricated by free-radical redox polymerization using ammonium persulfate (APS) and N, N, N??, N??-tetramethylethylenediamine (TEMED) as initiators and N, N??-methylene bisacrylamide (BIS) as cross-linker at 60°C. To create a hybrid hydrogel, 0.2% (mass fraction) of MgAl layered double hydroxide (LDH) was added to the aqueous solution by ultrasonic dispersion. The physicochemical properties of hybrid hydrogel under vacuum freeze-drying processing were characterized by Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM), while swelling kinetics and gel content were calculated. Swelling degree in distilled water varied from 94%?C125% with a gel mass fraction of 83%?C91%. SEM images showed that the micron pore size of hydrogel could be adjusted within the range of several micrometers by changing the cross-linker mass fraction from 2% to 10% (based on glycol). The results showed that the hybrid hydrogels exhibited excellent physicochemical behavior and might be a promising material for applications in tissue engineering and drug delivery.     

Degradation behavior of epoxy resins in fibre metal laminates under thermal conditions

GLARE (glass fibre/epoxy reinforced aluminum laminate) is a member of the fiber metal laminate (FML) family, and is built up of alternating metal and fiber layers. About 500 m² GLARE is employed in each Airbus A380 because of the superior mechanical properties over the monolithic aluminum alloys, such as weight reduction, improved damage tolerance and higher ultimate tensile strength. Many tons of new GLARE scraps have been accumulated during the Airbus A380 manufacturing. Moreover, with the increasing plane orders of Airbus A380, more and more end-of-life (EOL) GLARE scrap will be generated after retire of planes within forty years. Thermal processing is a potential method for the material recycling and re-use from GLARE with the aim of environmental protection and economic benefits. The current study indicatdes that thermal delamination is a crucial pre-treatment step for the GLARE recycling. The decomposition behavior of the epoxy resins at elevated temperatures was investigated by using the simultaneous thermal analysis, thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). Based on the thermal analysis results, GLARE thermal delamination experiments at refined temperatures were carried out to optimize the treatment temperature and holding time.     

基于RTI的协同仿真系统交互方法研究

本文分析了一般的协同仿真系统与基于HLA/RTI的协同仿真系统在工作原理、数据交互等方面的差异,以及基于HLA/RTI的协同仿真系统数据及命令交换实现的技术要点和基于RTI协同仿真平台的体系结构.从通用性角度探讨如何将一些无法直接参与基于HLA/RTI的协同仿真的专业仿真软件进行改造,使其能够以联邦成员身份加入到RTI联邦中参与协同仿真运行并实现系统数据及命令的正确交互.该研究为开发其他商用仿真软件实现基于RTI的协同仿真提供了参考价值.     

汽车电子机械制动系统

电子机械制动系统（EMB）,以电驱动元件为制动执行器,取代传统的液压或气压制动执行器.是一种全新的制动理念.它具有的没有制动液体、反应快速、性能可靠及安全环保等特点使其拥有令人看好的前景.在国外.EMB的研究取得初步的成绩,Bosch、Siemens公司已经研制出了自己的部分试验成果,而国内的研究刚刚开始.文章阐述了电子机械制动系统的概念、结构组成、工作原理及性能特点,论述了其关键技术及发展.     

德龙F2000牵引车底盘SKD发运装箱方案设计

重型牵引车德龙F2000出口SKD包装发运方案设计。对整车装配尺寸及各总成零部件装配关系分析,选用集装箱,确定整车拆卸方案及整车SKD装箱方案。解决重型牵引车德龙F2000的海外出口发运问题。     

基于图像内容和混沌系统的图像认证算法

提出了一种利用离散余弦变换（Discrete Cosine Transform,DCT）系数和混沌系统的可用于检测图像篡改定位的脆弱性数字水印算法.首先将图像进行不重叠的分块,分块后的图像经过DCT变化后,利用中频系数产生水印.同时利用混沌系统构成图像块间信息嵌入和提取的对应关系,并将水印嵌入到相关块的最低有效位.图像篡改检测过程为：将提取的水印和生成的水印进行比较,通过差异的位置对其进行定位.实验结果显示,该算法具有良好的定位精度,混沌系统的采用,使算法具有较高的安全性.     

高速开关磁阻电机的电感计算与运行分析

高速开关磁阻电机（SRM）常采用角度控制方式（APC）,因而准确计算电感曲线,确定开通关断角对电机的控制非常重要．本文采用能量增量法计算了SRM的静态电感和动态电感特性,分析比较得出动态电感能更好地反映电机的动态特性及饱和特性．根据高速运行的SRM动态电感,确定了合适的角度控制方案．基于有限元软件JMAG-studio,采用场一路耦舍方法,对高速SRM运行于APC的工况进行分析计算,得到了电机的磁场分布及电流、转矩特性．     

故障树分析法在船舶细水雾灭火系统故障查找流程图设计中的应用

文章通过对船舶细水雾灭火系统的工作过程及常见故障的分析,提出了用故障树分析法来对船舶细水雾灭火系统进行故障诊断,建立了船舶细水雾灭火系统故障树及其故障查找流程图。通过故障查找流程图轮机员能够快速准确地找出故障并及时排除故障,保证了船舶的安全航行。     

日本汽车产品市场准入召回制度

在分析日本车辆法规体系、型式认证、召回制度和节能要求的基础上,阐述了日本汽车产品的市场准入制度,对我国汽车产品破除发达国家技术性贸易壁垒具有较大的指导意义。