A Compact Fourth-Order Finite Difference Scheme for Unsteady Viscous Incompressible Flows

In this paper, we extend a previous work on a compact scheme for the steady Navier–Stokes equations [Li, Tang, and Fornberg (1995), Int. J. Numer. Methods Fluids, 20, 1137–1151] to the unsteady case. By exploiting the coupling relation between the streamfunction and vorticity equations, the Navier–Stokes equations are discretized in space within a 3×3 stencil such that a fourth order accuracy is achieved. The time derivatives are discretized in such a way as to maintain the compactness of the stencil. We explore several known time-stepping approaches including second-order BDF method, fourth-order BDF method and the Crank–Nicolson method. Numerical solutions are obtained for the driven cavity problem and are compared with solutions available in the literature. For large values of the Reynolds number, it is found that high-order time discretizations outperform the low-order ones.     

Java移动代码的授权访问研究

Java移动代码是一种可以通过网络从一台计算机传珐另一台计算机上运行的Ｊava程序,在现代网络计算及电子商务中具有广泛应用,Ｊava的这一显著特性也蕴藏着授权管理上的不足,未授权者可以很容易地非法使用这些程序,针对Ｊava移动代码的这些不足之处,分别对Ｊava Applet及Ｊava Applet及Ｊava Servlet提出了基于数字签名算法的授权与访问控制方案,安全,有效地解决了这种新兴的授权与访问控制问题。     

分布式环境下的并行处理ARC／INFO飞行动画生成技术

针对ARC／INFO系统中飞行动画生成速度慢的问题,分析了速度慢的原因,提出了用并行处理技术来加速的思想,设计了相应的并行算法,并在cluster结构上实现了飞行动画生成并行处理,经实际应用达到了提高计算速度,满足实时性要求的目的。     

基于Linux的文件系统对连续媒体的支持

从操作系统角度考虑了底层文件系统对连续媒体的支持,并详细介绍了Linux下设计和实现的BLOB(Binary Large Obiject)文件系统的设计思想及其实现技术细节,并讨论它对连续媒体的支持情况。     

基于性能的LUT结构的FPGA的再设计算法

本文提出一个基于性能的LUT结构的FPGA的再设计算法,该算法采用特征函数以及对原布尔网络进行相应的约束实现电路的再设计。因为不改变网络的拓扑结构,从而避免了在再设计过程中重新考虑电路的时延和布局布线结果。     

NetWare／FOXPRO数据库应用系统的安全

FOXPRO RDBMS是一种安全性很弱的关系数据库管理系统,而一般的FOXPRO数据库应用系统除了口令字机制之外,也很少有其它的保护措施。为此,本文提出一种称为“角色-视图”关系的适应于办公室环境的数据库访问控制策略。在这种策略的指导下,利用NO-VELL NetWare网络操作系统的安全机制,设计了一个在应用层上的FOXPRO数据库系统安全体系。本文所做的研究工作有两个特点：一是数据库系统安全的关键功能利用操作系统和机制来实现,所以系统整体在安全性、性能和开发费用上有较好的平衡;二是整个安全体系的设计符合安全工程的一般开发流程。     

Identification of nasopharyngeal carcinoma antigens that induce humoral immune response by proteomic analysis

A proteomics-based approach has been used to identify proteins that commonly elicit a humoral immune response in nasopharyngeal carcinoma (NPC). Sera from 19 newly diagnosed NPC patients and 19 healthy individuals were analyzed for IgG autoantibodies against NPC proteins resolved by 2-DE. Protein spots that exhibited selective reactivity with sera from NPC patients were identified by MS. Among nine identified proteins, cytokeratin 19 (CK19), Erb3 binding protein (EBP1), and Rho GDP dissociation inhibitor-beta (Rho-GDI-2) induced autoantibodies in more than 36.8% of NPC patients but not in healthy individuals. Furthermore, Western blot analysis and immunohistochemical staining were performed to determine the expression and localization of CK19, EBP1, and Rho-GDI-2 in NPC and normal nasopharyngeal mucosal tissues. Up-regulated CK19 and EBP1, but not Rho-GDI-2, were observed in NPC vs. normal tissue. Subcellular localization of the three proteins in NPC tissue was same as that in the normal tissue. Thus, overexpression of CK19 and EBP1 may be one of the mechanisms for their autoantibody development in NPC. To validate the findings of a proteomic analysis, occurrence of autoantibodies against these three proteins was detected by immunoprecipitation and Western blot analysis in additional 30 NPC patients, 23 other types of cancer patients and 20 healthy individuals. Results showed that frequency of autoantibodies against CK19, EBP1 and Rho-GDI-2 in NPC patients was significantly higher than that in other types of cancer patients and healthy individuals. We conclude that CK19, EBP1 and Rho-GDI-2 may have utility in NPC screening and diagnosis.     

邮政运输车辆管理系统及其实现技术

文章利用设备综合工程学的原理,并结合邮运生产的实际情况,介绍了基于Ｃ／Ｓ结构的邮政运输车辆调度及管理系统的开发方法与技术。探讨了运输企业技术管理中的几个重点和难点,并结合企业实际提出了有效的解决方法,对运输企业和车辆的现代化管理作出了有益的尝试。     

论拼音内码

本文指出现行的汉字编码在现实应用中的缺陷,提出编号内码和拼音内码的概念,并首次提出以拼音字母作内码的汉字拼音内码方案。