三峡地下电站变顶高尾水洞水动力特性

在国内首次应用模型水轮发电机组对三峡地下电站变顶高尾水洞方案进行水力过渡过程试验研究。对水轮机导叶实行分段关闭 ,并求出了二段关闭的最佳拐点 ,试验证实了二段关闭对减小尾水管进口的负压和机组转速上升有明显的作用。通过有关水力参数的测试 ,认为变顶高尾水洞可以满足各项技术要求 ,是一个减少山体开挖、节省投资的新型设计方案。在地下电站中具有广泛的应用前景     

变频器在暖通空调行业中的应用

本文提出中央空调系统的一种变频调速改造方案，介绍了该系统的结构组成及运行原理，对系统各部分的作用进行了讨论。     

高速逆流色谱(HSCCC)在食品色素制备中的应用

综述了高速逆流色谱在食品色素制备中的应用情况，包括溶剂选择、色素种类等。     

Extracellular polysaccharides production by Arthrobacter viscosus

In this study the production of extracellular polysaccharides by the non-pathogenic soil bacteria Arthrobacter viscosus has been investigated. Different variables affecting extracellular polysaccharide production such as the carbon source (glucose or xylose), the agitation speed and the pH have been analysed.

In a first stage, experiments in shaken conical flasks (250 ml), containing 50 ml of culture medium, were carried out. Using xylose (25 g/l) as the carbon source at an initial pH 8 improved the extracellular polysaccharides levels obtained.

In a second stage, the experiments were scaling in bioreactors. Cultivation was carried out in discontinuous mode and with/without pH control. Polysaccharide production reached a maximum of 10 g of crude product per litre of growth medium after 14 days and the relationship between product formation and cell growth of A. viscosus is 2.7 g polysaccharide per gram biomass. This production was obtained at the optimal conditions determined with pH control at pH 7, xylose as carbon source (25 g/l) and an agitation rate of 800 rpm.     

Experience, Context, and the Visual Perception of Human Movement.

Why are human observers particularly sensitive to human movement? Seven experiments examined the roles of visual experience and motor processes in human movement perception by comparing visual sensitivities to point-light displays of familiar, unusual, and impossible gaits across gait-speed and identity discrimination tasks. In both tasks, visual sensitivity to physically possible gaits was superior to visual sensitivity to physically impossible gaits, supporting perception-action coupling theories of human movement perception. Visual experience influenced walker-identity perception but not gait-speed discrimination. Thus, both motor experience and visual experience define visual sensitivity to human movement. An ecological perspective can be used to define the conditions necessary for experience-dependent sensitivity to human movement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

计算机高速并行通信的实现方案

利用CPLD芯片实现单片机与ISA总线接口之间的高速并行通信，给出系统的总体设计方法及程序框图。采用这种通信方式，在12MHz晶振的MCS51单片机控制的数据采集系统中，可以满足与PCI04 ISA总线接口实时通信的要求，通信速率达200khit／s。在开发工具MAX plusⅡ下，完成了整个设计的输入、编译和仿真，达到了预期效果。本设计方案能够推广应用到计算机的高速并行通信中。     

S7-226PLC与MM440变频器在光缆护套机中的应用

本文介绍了由西门子S7—226PLC与MM440变频器组成的电气控制系统在光缆护套机速度控制中的应用。并对该系统的控制原理作了详细的阐述。     

河北冶金实验厂8MN快锻液压机电控系统选择

着重阐述了河北冶金实验厂８ＭＮ快锻液压机电控系统的选择过程。经过反复考察，论证，对比，最终所选的压机电控系统为目前国产快锻液压机中自动化水平最高的锻造设备。     

可编程控制器在包装机上的应用

本文介绍了可编程控制器（PLC）在包装机上的应用．介绍了系统的硬件设计与软件开发．     

气流式加速度传感器的敏感机理

介绍了在研制气流式加速度传感器过程中，为对气流式加速度传感器进行建模，作者对气流式加速度传感器的工作机理进行了理论性探讨。在分析过程中以流体力学、传热学和惯性理论为基础并结合实验结果，建立了适合于气流式加速度传感器的气体运动方程和能量方程。同时还讨论了热线测量加速度的方法及根据实验分析了输入加速度对腔体内温度及传感器输出电压的影响，从而为进一步研究一系列气流式传感器的工作机理提供了方法。