面向多商户的第三方电子券系统设计与实现

电子券正成为商家促销的一种新技术手段.在一个已有的定制化电子券系统的基础上,针对服务于多商户的应用背景,对系统的需求进行了重新梳理和流程优化,给出了改造后的系统架构.同时,还对新系统的权限管理与访问控制问题进行了重点分析和设计,引入基于角色的访问控制模型,使之能支持面向多商户的管理.     

电子政务数据共享模式研究

互联网的广泛应用,改变了社会公众对政府信息需求的观念。加强电子政务数据共享是社会发展的必然要求。为了保证政务信息的有效共享,实现不同部门不同类型数据的转换和重用,提出了一种新的基于公开密钥基础设施体系构造数据共享模式。在新的数据共享模式中,使用电子凭证替代传统的纸质凭证,增加了行政审批事务办理的快捷性、安全性、低碳环保性。为了进一步提高电子凭证的效率,将其与云计算无缝融合。通过对具体应用案例的分析,表明新的数据共享模式具有安全性、可行性和实用性。     

双参数Bézier曲线的升二次扩展

本文以二次Bernstein基函数为例,首次提出了含双参数基函数的新扩展——αβQ—Bern-stein基函数,此类基函数具有新的特点,即基函数的扩展次数一次性升高两次,且包含了二次多项式和带一个参数的三次多项式基函数的所有性质。基于这组基函数定义了αβQ—Bézier曲线,该曲线也含有参数,具有形状可调性,当α与β取某些值时曲线能达到C4连续或在某个端点处C0连续。最后与含两个参数的升一次Bézier曲线进行比较,该曲线具有调节范围广、灵活性更强的优势。     

基于Cortex-M3的多功能楼宇控制系统网关节点设计

针对目前大多公司的楼宇日常办公耗电无法做到智能节能控制,提出了一种基于多功能网关节点的集中控制解决方案。设计中提出利用基于Cortex-M3的LPC1766作为网关节点,并且集成DHT11温湿度传感器,光线传感器和继电器控制电路等。通过RS485和终端节点通讯并且通过以太网与上位机通讯.最终实现远程楼宇节能控制的三层体系解决方案。     

颗粒增强复合材料中的界面层

本文对氧化铝(Al₂O₃)、氟化钙(CaF₂)和玻璃微珠颗粒填充环氧基(E51环氧—胺固化体系)复合材料的密度和动态力学性能进行了研究。结果发现由于颗粒填料表面和环氧基体的相互作用,从填料表面开始形成了一层致密的聚合物界面层。它的性质与本体树脂有明显的差别。把填充复合材料看成由填料、界面层和树脂本体组成的三元体系,从“临界填料含量”概念出发,求得了界面层的密度,界面层的厚度和界面层的体积分数。     

Nonlinear response of electron-phonon interaction inn-type nondegenerate piezoelectric semiconductors

The nonlinear response of the electron-phonon interaction in nondegenerate piezoelectric semiconductors such asn-type InSb in the presence of a dc magnetic fieldB directed along the propagation of acoustic waves has been studied by using a quantum mechanical treatment. The effect of electron scattering in solids has been taken into consideration, so the electron relaxation time cannot be neglected. The nonlinear nature of the energy band is corrected for, using the Heisenberg equation of motion. It is found that the nonlinear response is proportional to a nonlinear longitudinal conductivity tensor _zzz when acoustic waves propagate parallel to the [111] direction for both piezoelectric and deformation-potential couplings. Numerical calculations for _zzz of n-type InSb at low temperatures are presented. Results show that the nonlinear response decreases rapidly with the sound frequency, and decreases slowly with the dc magnetic field and temperature. Therefore, the electron relaxation time and the nonparabolicity of energy bands play important roles for the electron-phonon interaction due to the piezoelectric and deformation-potential couplings in the microwave region.     

Simultaneous analysis and design optimization of nonlinear response

The optimal structural design requiring nonlinear analysis and design sensitivity analysis can be an enormous computational task. It is extremely important to explore ways to reduce the computational effort so that more realistic and larger-scale structures can be optimized. The optimal design process is iterative requiring response analysis of the structure for each design improvement. A recent study has shown that up to 90 percent of the total computational effort is spent in computing the nonlinear response of the structure during the optimal design process. Thus, efficiency of the optimization process for nonlinear structures can be substantially improved if numerical effort for analyzing the structure can be reduced. This paper explores the idea of using design sensitivity coefficients (computed at each iteration to improve design) to predict displacement response of the structure at a changed design. The iterative procedure for nonlinear analysis of the structure is then started from the predicted response. This optimization procedure is called mixed and the original procedure where sensitivity information is not used is called the conventional approach. The numerical procedures for the two approaches are developed and implemented. They are compared on some truss type structures by including both geometric and material nonlinearities. Stress, strain, displacement, and buckling load constraints are imposed. The study shows the mixed method to be numerically stable and efficient.     

THERMAL DEBINDING OF A NEW BINDER

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三维微细电火花加工系统设计及实验研究

研究开发的三维微细电火花加工系统，包括微进给运动控制机构、高频微能脉冲电源、加工状态检测等关键环节。在工控机和相应板卡的硬件平台上，构建出基于Linux和RTLinux的数控系统，该系统对CAM的NC数据进行预处理，加入电极补偿和轨迹规划环节，从而实施三维微细结构样件的加工。     

绝缘门极双极性晶体管（IGBT）在焊接逆变器中的应用

本文介绍绝缘门极双极性晶体管(IGBT)的基本结构、工作原理、开关特性以及在焊接逆变器中的应用。