在线自学与考试系统的设计

本文将现有的在线自学与在线考试系统相结合,设计出一个具备教学与测试的完整的学习系统,并实现学习者学习进度记录、进度相互比较及经验交流等功能,使学习者在学习过程中并不孤独。     

高浓度制药废水处理工程实例

针对某制药公司废水主要成分为DMF、三乙胺、四氢呋喃等,新建1座废水处理厂,采用化学氧化—兼氧—好氧—接触氧化处理工艺.该类制药废水含盐量较高,需经稀释后再进行生化处理,经生化处理后二沉池出水可达《污水综合排放标准》(GB 8978-1996)二级标准.处理工艺恶臭气体采用收集—预处理—低温等离子处理—后处理—高空排放工艺进行处理,处理后可达《恶臭污染物排放标准》(GB 14554-93)二级排放标准.     

Effect of dy on structure and magnetic properties of CoPt alloys

The effects of Dy on the microstructure and magnetic properties of Dy _x Co_50?x Pt₅₀ alloys were investigated. The XRD results indicate that all the alloys homogenized at 1000 °C contain only a single A1 (fcc) phase, while the alloys annealed at 675 °C consist of a hard-magnetic face-centered-tetragonal (fct) phase and a magnetically soft face-centered-cube (fcc) phase. Maximum values for the coercivity H _c and remanence ratio m _r were achieved in Dy_0.4Co_49.6Pt₅₀ alloys annealed at 675 °C for 80 min. For the series of Dy _x Co_50?x Pt₅₀ alloys annealed at 675 °C for 60 min, H _c decreases monotonically with increasing Dy concentration, but m _r is first enhanced and then weakened.     

Effect of fiber orientation on the structural behavior of FRP wrapped concrete cylinders

In this study, 27 concrete cylinders with a diameter of 152.4 and a height of 304.8 mm were prepared. Among them, 18 cylinders were wrapped using two layers of fiber reinforced polymer (FRP) with six fiber orientations; six cylinders were wrapped using four layers of FRP with fibers in axial or hoop direction only; the remaining three cylinders were used as control. The FRP used was E-glass fiber reinforced ultraviolet (UV) curing vinyl ester. Fifteen coupon specimens were prepared to experimentally determine the tensile strength of the FRP with fibers oriented at 0°, 45°, and 90° from the loading direction. Co-axial compression tests were conducted on the wrapped cylinders and control cylinders. The test results were compared with existing confinement models. It is found that the strength, ductility, and failure mode of FRP wrapped concrete cylinders depend on the fiber orientation and wall thickness. Fibers oriented at a certain angle in between the hoop direction and axial direction may result in strength lower than fibers along hoop or axial direction. A larger database is desired in order to refine the existing design-oriented confinement models.     

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.     

Voice over wireless local area network

This paper introduces the special issue on voice over wireless local area networks (VoWLAN), which aim to foster interaction among researchers from both academia and industry in networking, wireless communications, and mobile computing. The special issue includes an article investigating the issue of determining an appropriate pricing strategy for VoWLAN provisioning. Also featured are two articles on polling as a solution for supporting real-time traffic over WLANs and another on media optimization network architecture (MONA).     

动画片制作样式的探索

一、动画的表现力 动画片作为艺术的一种载体，同其他艺术形式一样担负着传达人类情感与思想的媒介作用。不仅如此，由于动画片自身所特有的表现方法，使它的表现力往往会超越其他的艺术载体，要比文字、绘画、音乐更有表现力。     

基于IADS的多库协调器的研究及应用

知识管理系统中的核心问题之一就是多库协同问题,利用智能自律分散系统(IADS),设计了一个基于智能自律分散系统的知识管理多库协同系统,解决知识管理中的多库调度、多库协调、资源共享等问题。     

DPD技术在软件无线电中的应用研究

重点对基于多速率数字信号处理的正交采样和解调等几点关键技术进行了研究。针对现有模拟和数字正交采样系统的优缺陷,论文就一种新的采样方法——DPD(Digitalproductdetector)采样技术,分别从时域和频域对该技术进行了理论分析和计算机仿真。     

RS-485总线型通讯系统应用

通过举例说明，本文介绍了用RS-485构成主机方式通信风格的应用组网方法。