基于CORBA框架的RPC包装集成技术

文章从分析系统集成策略对信息系统研究和发展的重要作用入手,阐述了建立通用一致应用系统集成框架的重要性,并给出基于ＣＯＲＢＡ规范的集成框架总体结构及实现策略;在此基础上实现了ＲＰＣ部件的包装集成,并对遇到的关键技术问题进行论述。     

基于Windows NT局域网络全真模拟Internet操作测试功能的实现

文章介绍一种基于Ｗｉｎｄｏｗｓ ＮＴ局域网络,在Ｗｉｎｄｏｗｓ ９５／９８平台上使用的全真模拟Ｉｎｔｅｒｎｅｔ操作测试功能的实现方案,重点介绍了题库工作表结构,全真模拟Ｉｎｔｅｒｎｅｔ环境,操作考核主页设计及其相关技术要点。     

一种基于模块化结构的大学英语四级MCAI系统实现方法研究

Authorware是一种优秀的多种媒体开发工具,能实现非常复杂的多媒体接入及程序流程控制,但在开发功能结构类似,信息资源丰富的模块时,还存在程序设计复复,代码重复量大,模块功能更改困难等问题,本文针对以上问题,在设计大学英国四级多媒体教学系统时,提出了一套基于模块化结构的大学英语四级MCAI教学软件的设计思想,并以听力部分为例,详细介绍了该部分各功能模块的实现。     

GENOTOXICITY IN CHIRONOMUS KIIENSIS (CHIRONOMIDAE: DIPTERA) AFTER EXPOSURE TO POLLUTED SEDIMENTS FROM RIVERS OF NORTH PENINSULAR MALAYSIA: IMPLICATION FOR ECOTOXICOLOGICAL MONITORING

Rapid industrialization and urbanization has led to increasing input of chemical contaminants into the aquatic environment of Malaysia. Despite the threat civilization poses to the biota, there are still very few relevant studies on ecotoxicological testing of river ecosystems. To overcome this knowledge gap, we examined lethal and genotoxic effects of sediments from different rivers of the northern Malaysia against Chironomus kiiensis, a group well represented in the aquatic fauna of this region. We exposed the larvae to sediments from Selama River (SR), Permatang Rawa River (PRR) and Kilang Ubi River (KUR) at various durations (0, 6, 12, 24 and 48 h). The larval mortality was monitored, whereas DNA damage in survivors' cells was determined using the comet assay. Pollution level indexed by the amounts of heavy metals and other organic contaminants in the sediment showed progressive increases from SR to PRR to KUR. Highly polluted sediments (PRR to KUR) were detrimental to C. kiiensis larvae, most of which did not survive following exposure for long periods. DNA analyses revealed greater damages in nuclei derived from larvae maintained on polluted sediments, in particular, those from KUR. The effects on the genomic material of C. kiiensis larvae occurred in a time‐dependent manner, with damage level increasing as exposure time progressed. Our results highlight the genotoxic properties of polluted sediments. More importantly, this study showed that C. kiiensis larvae could respond to different levels of pollution with respect to exposure time. It is concluded that C. kiiensis larvae is a potential candidate for river ecotoxicological monitoring. Copyright © 2012 John Wiley & Sons, Ltd.     

北斗系统C频段导航信号的波形设计

在分析比较C频段和L频段信号传输特点的基础上,通过信号的兼容性、导航性能以及接收机实现复杂度约束条件的折中,提出基于椭圆球面波函数PSWF(Prolate Spheroidal Wave Functions)的C频段信号波形设计方案。仿真结果表明,基于PSWF的优化信号具有良好的带外抑制特性,满足C频段信号设计的严格兼容性约束要求,并具有优于传统BPSK调制的跟踪测距精度和抗多径性能。     

Modeling and simulation for a drop-impact analysis of multi-layered printed circuit boards

Multi-layered printed circuit boards (PCBs) contain a multi-layered structure that is suitable for high-speed and high-frequency applications. Hence, they are used extensively in electronic packaging assemblies for high-density applications. However, numerous composite parts and complex material properties of multi-layer PCBs complicate the reliability simulation of PCB model. This paper deals with a finite element analysis intended to describe numerically the behavior of multi-layered multi-materials PCB model (combination of metallic and composite plies) in the drop-impact performance. Through the comparison of physical drop test results, the fully multi-layered model illustrates higher accuracy if compared with that of the traditional simplified isotropic model and orthotropic model. The effects of material properties for the multi-layer PCB under drop-impact shock have also been investigated.     

城域以太网物理拓扑发现算法研究

在现代城域以太网中,自动物理拓扑发现对提高管理效率非常重要,然而当前存在的一些商业化的网络管理工具主要是针对逻辑拓扑发现或某种设备的管理。而在[1]-[3]中的算法主要是依赖标准的SNMP的AFT信息,在网状的网络中,这种条件只能发现生成树路径。我们的算法能发现包括生成树中非激活的接口在内的完全的物理拓扑。     

载银纳米SiO2制备与抗菌性研究

在60%硫酸乙酯催化下TEOS水解,通过控制水解条件,得到担载体纳米SiO2。采用吸附法在其表面负载银,制备无机抗菌材料。用抑菌圈直径和杀菌率表征粉末抗菌性能,研究了吸附时间、硝酸银浓度及吸附温度与负载量的关系,并考查了焙烧温度等因素对抗菌性能的影响。研究发现,以离子形式存在的贵金属银的抗菌性能强,焙烧处理温度决定其离子溶出性与可重复使用次数。     

Exploring Two-Wave Reciprocal Structural Relations Among Orthographic Knowledge, Phonological Sensitivity, and Reading and Spelling of English Words by Chinese Students.

In a 2-wave study of a cohort of 108 Chinese students (10- to 11-year-olds) learning English as a second language, the authors examined the relative effects of three Time 1 latent constructs-- orthographic knowledge, phonological sensitivity, and word identification (reading and spelling of regular and exception words)--on the respective Time 2 performance. The authors posited autoregressive effects, in which Time 1 constructs affected their matching Time 2 performance (e.g., Time 1 orthographic knowledge on Time 2 orthographic knowledge), as well as reciprocal cross-domain effects (e.g., orthographic knowledge on word identification and vice versa). The model converged to a proper solution with reasonably good fit. The results suggest (a) strong stability in the children's word identification and phonological sensitivity, (b) substantial effects of word identification on subsequent orthographic knowledge and phonological sensitivity, particularly the former; and (c) greater variations in individuals' growth of orthographic knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)