Fracture and mechanical properties of P100 Gr/6061 Al composite

The effects of heat treatments on the mechanical and fracture properties of continuous fiber Pitch 100 graphite/6061 aluminum (P100 Gr/6061 Al) composite were evaluated by varying solution temperature and aging time. All heat treatments resulted in decreased mechanical properties due to the reaction at the fiber/matrix interface during solution treatments. SEM analysis of the fractured samples showed a large degree of fiber pullout, interface failure, and matrix cracking.     

Temperature Dependence of the Magnetocrystalline Anisotropy in Nd_2Co_(14)B Compound

Easy and hard magnetization curves of Nd_2Co_(14)B compound have been measured withextracting-sample-magnetometer(μ_0H_(max)=6T)at 10～300 K.Magnetic anisotropy constants K_1 and K_2have been determined by fitting the hard magnetization curves,in which only K_1 ,K_2 and misalignment anglehave been taken as fitting parameters.The values of K_1 and K_2 at 4.2 K were derived by extrapolation.Anisotropy coefficients,x_2~° and x_4~°were derived from the anisotropy constants.The anisotropy constant K_2increases rapidly with increasing temperature when TT_(sr).The temperature depen-dence of the magnetic anisotropy coefficient x_2~° was fitted with the formula.The anisotropy coefficients x_2~°can be well described by the tenth-power law from 4.2 K to T_(sr)and by the sixth-power law from T_(sr_ to 300 K.     

Preparation and characterization of GaN films grown on Ga-diffused Si （111） substrates

Hexagonal GaN films were prepared by nitriding Ga2O3 films with flowing ammonia. Ga2O3 films were deposited on Ga-diffused Si (111) substrates by radio frequency (r.f.) magnetron sputtering. This paper have investigated the change of structural properties of GaN films nitrided in NH3 atmosphere at the temperatures of 850, 900, and 950℃ for 15 min and nitrided at the temperature of 900℃ for 10, 15, and 20 rain, respectively. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were used to analyze the structure, surface morphology and composition of synthesized samples. The results reveal that the as-grown films are polycrystalline GaN with hexagonal wurtzite structure and GaN films with the highest crystal quality can be obtained when nitrided at 900℃ for 15 min.     

电场固溶对2091A1-Li合金显微结构的影响

用电子探针及透射电镜研究了２０９１ＡｌＬｉ合金的电场固溶对显微结构的影响。结果发现，电场固溶通过促进含铜相溶解提高铜元素的固溶程度，加剧Ｌｉ原子在晶界上的非平衡偏聚，导致析出相δ′分布不均匀，体积分数减少，晶界上出现粗大的δ平衡相，Ｔ１及Ｓ′相均匀弥散分布，合金的力学性能（Ｔ６）达到了应变时效处理（Ｔ８）的水平。     

模具生产联合体加工作业统一调度问题的研究

模具生产联合体是由小规模企业组成的模具设计、制造联盟，由于设备、工装和人员分属于不同的加盟企业，其作业排序过程非常复杂。为此提出一种复合式模具生产联合体的生产排序方法：依据基本优先规则首先完成单一工序作业，然后对多工序作业用改进遗传算法进行工艺优化，求出最优解和次优解，再使用评价函数法选择最佳作业路线。该方法在生产试验中取得了良好的成效．能较好满足模具用户和加盟企业两方面的需要。     

中英规范有关建筑物防雷接地做法的比较

结合国家标准GB 50057-2010《建筑物防雷设计规范》和BS规范BS EN 62305-2006《Protection against lightning》,介绍了两本规范中建筑物防雷装置做法,简述了两种规范中有关建筑物外部防雷(接闪器、引下线、接地装置)、内部防雷以及防雷击电磁脉冲的有关规范条文规定和比较。     

一种新型不同容量逆变器并联方法

传统的逆变器并联方法一般只适用于功率容量一致的逆变器,针对不同容量逆变器的并联方法较少。本文在对几种不同容量逆变器并联方法分析研究的基础上,提出了一种新型的逆变器并联方法。该方法采用电压型逆变器和电流型逆变器混合并联的方式,利用电压型逆变器提供电压基准,电流型逆变器输出电流可以稳定电网电压,实现并联。该方法算法简单,适合大部分的逆变器并联场合,经过仿真和实验证明了其有效性和可行性。