浅谈通用串行总线(USB)

阐述了USB的发展历程，介绍了通用串行总线USB的优点及不足之处，系统分析了USB基本框架与总线框架、物理接口、数据流传输模式、编码方式等基本问题，推荐了几种USB产品。     

医学图书馆馆藏光盘资料的管理与利用

以医学图书馆馆藏光盘资料为例,介绍了光盘资料的定义、分类、著录和管理使用。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

盘鼓混合式转子建模与动力学特性

首先, 针对大型旋转机械中混合式转子的转盘、 鼓筒组合旋转构件抗弯曲的高刚性特点, 将盘鼓混合旋转构件近似为刚性圆柱体, 并建立厚转盘转子系统动力学模型; 其次, 考虑转轴弯曲特性和所储弹性势能, 以曲线拟合结合Hermite插值法计算转轴弯曲刚度. 对比传统Jeffcott转子系统进行数值算例的分析结果表明, 转盘厚度是影响转子系统动力学固有特性的主要因素之一.     

基于USB接口的PC机读卡器设计

使用通用串行总线(USB)作为PC机读卡器与计算机的通信接口,设计了基于Prolific公司的PL2303芯片的硬件接口电路,并介绍了USBPC机读卡器的设计方法,包括设备端的硬件设计和软件设计     

双头磁盘系统的实时调度算法

对双头磁盘系统模型和调度算法进行实时化扩展,设计了三种实时调度算法：最早截止期优先（ＥＤＦ）算法,可满足的最早截止期优先（Ｆ－ＥＤＦ）算法和忽视超期限请求（ＩＧＭ－ＥＤＦ）算法．由于这三种算法充分考虑了Ｉ／Ｏ请求的截止期限,使双头磁盘系统能满足更多的实时Ｉ／Ｏ请求．实时调度算法的性能模拟实验表明：实时调度算法比非实时算法能更好地满足实时Ｉ／Ｏ请求的期限要求．三种实时调度算法中,ＩＧＭ－ＥＤＦ的性能最好,它很适用于硬实时应用;Ｆ－ＥＤＦ算法的性能次之,它最适合于软实时应用．     

淀粉-丙烯酸-丙烯酰胺共聚物合成新工艺

研究了淀粉－丙烯酸－丙烯酰胺接枝共聚制备高吸水性树脂的新工艺．“中试”及产品性能测试结果表明,盘式聚合工艺简便、易操作,对设备结构无特殊要求,成本低,所得到的产品具有较高的吸水率和吸水速率     

屏蔽效能自动测试系统设计与实现

自主研制了一套平面材料屏蔽效能自动测试系统,可对平面材料进行屏蔽室窗口法和同轴传输线法测试。该系统由屏蔽室、脉冲信号发射设备和测量接收设备等构成。系统硬件采用当前流行的USB／GPIB接口连接方式;软件基于Lab-Windows／CVI平台进行开发,采用了一个通用自动测试系统软件框架,提高了测试系统的通用性、灵活性、可维护性和可扩充性。利用Lab Windows／CVI编写测量和数据处理程序,实现了数据采集和处理自动化,提高了屏蔽效能测试的效率和精确度。     

汽车盘式制动器密封性工艺试验台的开发

为了消除汽车盘式制动器总成存在的渗漏现象,研制了一种先进的盘式制动器定量气密性试验台,采有定量差压法的原则检测盘式制动器的微泄漏。该试验台主要由气源增压系统、工件气动定位系统、测量系统和电气控制系统等组成。介绍了试验台的构造和工作原理,同时,利用该试验台进行了相应的试验研究。结果表明,所开发的盘式制动器密封性试验台,消除了IVECO汽车液压盘式制动器在整车上的渗漏现象,对稳定盘式制动器产品质量提供了保证。     

基于USB2.0的激光切割机高速数据传输

本文采用CYPRESS公司的CY7C68001作为USB收发控制芯片,以TI公司TMS320F2812为微处理器控制芯片设计了USB2．0接口方案．该方案完成了USB设备的硬件连接和软件实现,并成功应用于激光切割机系统．实际测试证明,USB2．0接口的实际数据传输速度最高可达200Mbps,完全满足激光切割机控制系统高速、实时传输的要求．