基于ADS的多通道下变频器仿真设计

重点讨论L波段多通道下变频器的设计与仿真。采用自上向下的方法,以Agilent ADS软件为平台建立仿真模型,选用S参数和谐波平衡仿真工具对多通道下变频器信道进行设计仿真,经过优化得到低噪声、高动态的仿真指标,实现多通道变频方案的可行性论证。     

亚甲二醇二硝酸酯的构象和热解机理的理论研究

用量子化学中的ＳＣＦ－ＭＯ ＭＩＮＤＯ／３，ＭＮＤＯ，ＡＭ１和ＰＭ３方法计算研究了亚甲二醇二硝酸酯的几何构型和电子结构２，求得了ＭＧＤＮ的平衡几何构型。不同方法的计算结果均表明，标题物分子中两个ＯＮＯ２均为平面基团，且Ｏ－ＮＯ２键的Ｗｉｂｅｒｇ键级最淖分子中最弱的键，在分解时可能首先断裂；     

机构动态演示的制作

使用Flash软件制作机构动态演示计算机辅助教学课件 ,并能够通过按钮指令控制机构运动。说明了如何将其插入到软件FrontPage中在网上发布 ,利用此方法 ,可以制作多种网上发布的课件。     

从31．5秒所想到的——论现阶段民航空管设备运行风险及防范

民航空管部门是直接保障飞行的，而空管设备则是空管部门有效开展工作、保障飞行安全重要的物质基础，这就需要确保设备的完好率与正常运行。然而，任何设备在单机运行条件下是不会达到100％的设备正常率的，况且这几年空管系统引进的很多设备存在型号杂、不兼容的问题，缺乏可靠性；部分地区的设备老化现象严重，故障率较高。在这种情况下，本文作者提出“从31．5秒所想到的——论现阶段民航空管设备运行风险及防范”的命题，并从五个方面提出了解决的办法，是很有针对性的，应当引起空管全系统、特别是空管设备保障部门的深思与重视。     

水平轴风轮空气动力性能的分析计算

本文用半刚性尾流模型近似表示给出水平轴风轮空气动力性能的分析计算方法。在高尖速比范围内，本方法给出的结果比动量理论给出的更加接加接近实验数据。     

航天测量船试验文书标准化模式研究

在分析航天测量船试验文书现状的基础上,从标准化要求出发,提出航天测量船试验文书两级两类四综合标准化模式及其基本框架和实现途径。     

Data association for deghosting in Y-shaped passive linear array sonars

This paper deals with data association using three sets of passive linear array sonars (PLAS) geometrically positioned in a Y-shaped configuration, fixed in an underwater environment. The data association problem is directly transformed into a 3D assignment, which is known to be NP hard. For generic passive sensors, it can be solved using conventional algorithms, while in PLAS, it becomes a formidable task due to the presence of bearing ambiguity. Thus, the central issue of the problem in PLAS is how to eliminate the bearing ambiguity without increasing tracking error. To solve this problem, the 3D assignment algorithm used the likelihood value of only those observed bearing measurements is modified by incorporating frequency information in consecutive time-aligned scans. The region of possible ghost targets is first established by the geometrical relation of PLAS with respect to target. The ghost targets are then confirmed and eliminated by generating multiple observations in consecutive scans. Representative simulations demonstrate the effectiveness of the proposed approach.     

Performance of a simple Closed Aquatic Ecosystem (CAES) in space.

A simple Closed Aquatic Ecosystem (CAES) consisting of single-celled green algae (Chlorella pyrenoidosa, producer), a spiral snail (Bulinus australianus, consumer) and a data acquisition and control unit was flown on the Chinese Spacecraft SHENZHOU-II in January 2001 for 7 days. In order to study the effect of microgravity on the operation of CAES, a 1 g centrifuge reference group in space, a ground 1 g reference group and a ground 1 g centrifuge reference group (1.4 g group) were run concurrently. Real-time data about algae biomass (calculated from transmission light intensity), temperature, light and centrifugation of the CAES were logged at minute intervals. It was found that algae biomass of both the microgravity group and the ground 1 g-centrifuge reference group (1.4 g) fluctuated during the experiment, but the algae biomass of the 1 g centrifuge reference group in space and the ground 1 g reference group increased during the experiment. The results may be attributable to influences of microgravity and 1.4 g gravity on the algae and snails metabolisms. Microgravity is the main factor to affect the operation of CAES in space and the contribution of microgravity to the effect was also estimated. These data may be valuable for the establishment of a complex CELSS in the future.     

双CPU环境下飞行控制软件的设计

本文介绍运载火箭飞行控制软件在双ＣＰＵ冗余硬件配置下的可靠性设计和可靠性指标分配的方法。文中提到的部分技术经过了实验的检验，证明是可行的     

长盛不衰 百年犹荣--一个颇具盛名的标准化团体ASTM

回顾了ＡＳＴＭ的建立过程，该机构目前已有３００００多个国内外会员，１３１个技术委员会，每年都出版标准年鉴，标准被世界各国广泛采用，与美国国防部标准化部门及其他标准化机构有广泛的联系，活动经费主要依靠出售标准和提供标准化服务的收入。