HULL GESTURE AND RESISTANCE PREDICTION OF HIGH-SPEED VESSELS

Since trim and sinkage are significant while vessels are advancing forward with high speed, the predicted vessel resistance based on restrained model theory or experiment may not be real resistance of vessels during voyage. It is necessary to take the influence of hull gesture into account for oredicting the resistance of high-speed ship. In the present work the resistance problem of high speed ship is treated with the viscous flow theory, and the dynamic mesh technique is adopted to coincide with variation of hull gesture of high speed vessel on voyage. The simulation of the models of S60 ship and a trimaran moving in towing tank with high speed are conducted by using the above theory and technique. The corresponding numerical results are in good agreement with the experimental data. It indicates that the resistance prediction for high speed vessels should take hull gesture into consideration and the dynamic mesh method proposed here is effective in calculating the resistance of high speed vessels.     

利用紫外光刻技术进行SU8胶的研究

SU 8光刻胶优异的性能在MEMS技术的发展重得到了广泛的应用 ,已经成为MEMS研究中必不可少的方法之一。SU 8光刻胶能够进行厚度达毫米的结构研究工作 ,另一方面SU 8结构具有很好的侧面垂直结构 ,通过控制工艺参数 ,能够获得满意的SU 8胶结构。SU 8光刻胶已应用于LIGA技术的标准化掩模制造工艺和一些器件的研究工作。在SU8胶研究过程中 ,克服了许多技术难题 ,使得这一技术能够应用到实际的需要中。     

金属卤化物气体放电灯启动问题的探讨

本文介绍了分别改变灯内填充物含量即 NaI 和 ScI 含量的方法,探讨此变化与光源气体放电参数的关系,从而分析和研究金属卤化物灯的启动特性,从而寻求延长光源寿命的途径。     

A 22-kHz multibit switched-capacitor sigma-delta D/A converter with92 dB dynamic range

A time- and capacitor-multiplexing technique for use in a highly linear switched-capacitor multibit DAC in sigma-delta data converters is presented. The technique uses subintervals in the sample clock to deliver multiple charge packets to holding capacitors. It avoids distortion effects caused by mismatched capacitors and finite opamp gain. A five-level switched-capacitor DAC using the proposed technique was designed as part of an audio-band multibit sigma-delta D/A converter that achieved a dynamic range of 92 dB and a THD of -93 dB with a low oversampling ratio of 32. No trimming, calibration, or dynamic matching scheme was required. The five-level SC DAC has been fabricated in a 2-μm CMOS process, and testing confirmed the anticipated theoretical results     

交互电视与应用

交互电视（ITV）是一种基础结构。这种结构提供了为数众多的硬件、软件和应用平台，这一点很像INTERNET。INTERNET也是一种结构，在它的上面有很多的硬件（服务器、客户机、调制解调器）、软件（WWW浏览器、WWW服务器程序、电子邮件服务器、通讯协议）和服务（FTP、电子邮件、新闻组、WWW）。     

A multiple access scheme for multimedia traffic in wireless ATM

This paper proposes a multiple access scheme for the forthcoming wireless ATM (Asynchronous Transfer Mode) system. Such ATM compatible wireless systems are motivated by the rapidly increasing demand for wireless extensions to broadband networks, which are expected to support mixed broadband services including Constant Bit Rate (CBR), Variable Bit Rate (VBR), and Available Bit Rate (ABR) traffic. Since these different traffics have very different performance requirements, the multiple access scheme design is very challenging. In this paper, we propose a multiple access scheme called Dynamic Time Division Multiple Access with Piggybacked Reservation (DTDMA/PR), attempting to achieve higher statistical multiplexing efficiency in the mixed VBR/CBR/ABR traffic scenario. The basic idea is to exploit two levels of reservation. The first level deals with the isochronous nature of CBR and VBR traffic and the bursty nature of ABR traffic by using the ALOHA reservation procedure. The second level exploits the piggybacked reservation approach to cope with the dynamic feature of VBR traffic in order to increase the multiplexing efficiency. An analytical model is also developed in this paper and verified by simulation. Numerical examples are given to gain some insight into the protocol itself.     

电力系统混合优化的模拟进化方法

电力系统中有许多混合优化问题,采用常用方法求解难以奏效,而模拟进化方法是一种新型有效的优化方法,文中提出模拟进化方法中处理混合优化问题的两种办法,即离散变量连续化及连续变量离散化,并将其应用电力系统功率,电容器组的优化问题,结果表明所提方法是可行的。     

高举邓小平理论伟大旗帜认真贯彻落实十五大精神以新一轮思想大解放促进湖北邮电新一轮大发展--在第36次全省邮电工作会议上的报告

同志们: 这次会议的主要任务是,以党的十五大和中央经济工作会议精神为指导,以全国邮电管理局长研讨会和全省经济工作会议为依据,总结1997年全省邮电工作,安排部署1998年的工作任务,动员全省邮电部门坚定不移地高举邓小平理论伟大旗帜,全面认真贯彻落实十五大精神,以新一轮思想大解放,促进湖北邮电新一轮大发展!     

High Temperature Superconducting Magnetic Energy Storage and Its Power Control Technology

High temperature superconducting （HTS） power inductor and its control technology have been studied and analyzed in the paper. Based on the results of simulations and practical experiments, a controlled release scheme has been proposed and verified for developing a practical HTS SMES prototype.