A high‐gain dual‐band directional/omnidirectional reconfigurable antenna for WLAN systems

A high‐gain dual‐band antenna for the wireless local area network system is presented in this article. Two symmetrical linear arrays can be dynamically reconfigured that could switch radiation pattern with a switchable feed circuit between direction and omnidirection. The antenna can also be used for a pattern diversity antenna for the multiple‐input–multiple‐output communication systems. The design process for the antenna system is given, and the parameters and characteristics of the antennas are achieved by the method. Measured return losses, isolation, and radiation patterns are in good agreement with the simulated ones, which illustrates that the method is valid and the antenna system can be integrated with pattern reconfigurable and pattern diversity applications. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

V2O5薄膜的电学性质及其应用

综述了Ｖ２Ｏ２薄膜材料的结构、电学性质及其在电学中的应用。     

粮库用30点温度巡测仪的研制

介绍一种体积小，成本低，操作简便，经济实用的粮库用30点温度巡测仪，并详细地阐述了该仪器的工作原理及制作，校正等操作性较强的经验和方法。     

石油钻杆摩擦焊机动态转速测量系统的研制

用霍尔元件代替旋转编码器测量主轴转速，适用于无法安装旋转编码器的设备或转速范围特别大的系统，目前已成功应用于宝钢钢管分公司石油钻杆摩擦焊机上。其特点是采用单片机系统对摩擦焊过程中的瞬时速度及压力，焊接缩短量作０．１ｓ间隔的定时采样和储存，并通过ＲＳ－２３２串行通信方式传送到上位ＰＣ机，进行显示，记录或打印。     

用挤出滚圆法制造球形微丸微粒的基本方法和设备

由于球粒在造粒中有着优越的性能，开发用工业方法制备大小均一、圆球度好、表面光洁的球粒造粒方法有着巨大的应用前景。医药工业缓释、控释制剂的发展更迫切需要开发大规模制造球粒的方法和设备。本文介绍了用挤出滚圆方法制造球形微丸微粒的方法和设备。最新开发、研制的专利产品－球形微丸造粒机能够以工业规模批量制造球粒微丸。球粒造粒容易、效率高。本设备不但可以为医药缓释、控释制剂新品种的开发提供装备，也可为食品、化     

Development and evaluation of active packaging for sliced mozzarella preservation

Antimicrobial films were formed by the incorporation of nisin (NI), natamycin (NA) and a combination of both (NI + NA) into cellulose polymer. Film efficacies were evaluated in vitro against Staphylococcus aureus ATCC 6538, Listeria monocytogenes ATCC 15313, Penicillium sp. and Geotrichum sp. The films were also evaluated on sliced mozzarella cheese against moulds and yeasts, Staphylococcus sp. and psychrotrophic bacteria. Mechanical and microscopic properties of the films and the diffusion of the antimicrobial agents from the film to the cheese were also evaluated. Films containing NI showed an antimicrobial effect in vitro against S. aureus and L. monocytogenes, while films containing NA were effective in vitro against Penicillium sp. and Geotrichum sp. By the ninth day of storage at 12 ± 2°C, the count of yeasts and moulds on cheese covered with films containing NA decreased 2 log10 units compared with the count on cheese with control films. NI film did not show an effect against Staphylococcus sp., but it was effective against psychrotrophic bacteria for 6 days of storage of the cheese. The incorporation of antimicrobial compounds decreased the resistance and elongation of the films and caused changes in their molecular conformation. NI diffusion from the films to the cheese was not detected; however, time‐dependent diffusion of NA from the film containing NI + NA was measured. The incorporation of NI and NA together in the films did not show an effect. The film containing NA showed potential for application as active food packaging for sliced mozzarella cheese. Copyright © 2008 John Wiley & Sons, Ltd.     

户内路灯节能电子开关的研究

介绍两种结构简单、成本低廉、工作可靠、调整方便的户内路灯瞬时打开、延时自动关断的开关电路。采用此开关,既可大大节省电能,也可使路灯的寿命得到延长。     

A high-performance switch fabric for integrated circuit and packet switching

This paper describes an architecture for a high-performance switching fabric that can accommodate circuit-switched and packet-switched traffic in a unified manner. The switch fabric is self-routeing and uses fixed-length minipackets within the switching fabric for all types of connections. Its kernel architecture is based on a routeing topology with individual connection paths from all inputs to all outputs and with FIFO queuing at each output. Owing to the disjoint connection paths, there is no internal blocking, and because of output queueing, output port blocking is prevented to a great extent. The uniformity in architecture allows construction of any size fabric from a single basic module which could be realized on a single chip. Larger-size configurations can be realized either as single-stage or multistage configuration. The second part of this paper discusses performance aspects and gives results and dimensioning guidelines for both circuit-switched and packet-switched traffic.     

快速启闭阀的常见故障分析及分析步骤

从动作原理和状态反馈这两个回路入手。分析本公司热电站快速启闭阀的故障现象，并对故障分析步骤作了详细总结。