Effect of air flowrate on particle velocity profile in a circulating fluidized bed

The research was conducted in a cold flow circulating fluidized bed (CFB). The diameter and height of riser are 5 and 200 cm, respectively. The objective is to study effect of gas velocity on hydrodynamic of glass beads having mean diameter of 547 micron and density of 2,400 kg/m³. The measurement of particle velocity profile was achieved by using a high-speed camera and an image processing software. A probe of 0.5 cm in diameter was inserted into the riser at the height of 110 cm from gas distributor and was set at 3 positions along the radius of the riser; 0, 0.6, and 1.8 cm from center. Transport velocity (U _tr ), core-annulus velocity (V _CA ) and minimum pneumatic velocity (V _mp ) were employed in determining solid flow pattern in the riser. It was observed that the flow regimes changed from fast fluidization to core-annulus and to homogeneous dilute bed when the gas velocities increased from 7, 8 and 9 m/s, respectively. The results from high-speed camera showed that glass beads velocity existed a maximum value at the center of the riser and gradually decreased toward the wall for all three gas velocities. It was also found that most of solid traveled upward in the core of the riser, however, solid traveled downward was identified at the wall layer.     

AutoCAD系统中运动副仿真系统的构造

根据运动副的特点，运用AutoCAD计算机辅助设计系统，以提高设计工作效率和正确性为目的，讨论了运动副仿真系统的构造及其具体应用。     

机器视觉系统中摄像机定标策略

摄像机定标是从拍摄的二维图像中获取三维信息必不可少的步骤，一直为机器视觉领域的研究热点之一。本文阐述了几种定标方法的基本原理，并论述了如何在工业视觉系统中根据不同的任务来选择不同的定标方法问题。     

苯-沥青溶液浓度的自校正测量方法及实现

介绍一种自校正方法及在以单片机为核心的苯-沥青溶液浓度仪中的实现。该方法在浓度分析过程中，克服了环境温度对硅光电池的影响，从而提高了测量精度。     

宽幅相机一体化焦面调整机构设计与精度分析

针对空间宽幅相机对调焦和调偏流的要求,设计了一种一体化焦面二维调整机构,能够同时实现调焦和调偏流功能,并基于蒙特卡罗法对机构进行了精度分析。机构总重12kg,调焦范围为(-4^+4)mm,调焦单元定位精度优于0.0045mm,调焦分辨力优于2.1μm;调偏流单元调偏流范围为(-5^+5)°,定位精度为1.48",调偏流分辨力优于0.18",各项指标均满足设计要求。一体化焦面二维调整机构结构紧凑,占用空间小,结构强度好,承载能力强,适用于大尺寸焦面空间相机。     

Multi-camera interface with novel copositioning

This article reports a multi-camera system to determine the position of an object. By using novel copositioning and cameras in a wide range of orientations and viewing angles, the system solved the problem of dead zones and camera switching errors. When an object was close to a charge-coupled device camera, the system switched to that camera to become the focus by the algorithm. When an object left the optimum range of one camera, the system selected the next suitable camera to be the main detector. The position of the target and the grey level thresholds were continuously recorded and the changes were calculated. This interface system had the advantages of high positioning accuracy, fast response time, reduced noise in the light field, and no dead zones.     

数字视频系统接口应用

随着技术发展,数字视频接口逐步替代模拟视频接口,成为视频产生、传输、显示、存储的主要方式.列举了常用的模拟和数字接口,阐述了视频系统前端与后端数字视频接口的特点及应用情况.通过分析各个端口的性能和实际军事需要,得出Camera Link接口是现在军用光电产品中的主要发展和应用方向.并且从接口的发展趋势来看,未来的数字接口是向摄取速度更高、传输带宽更宽、分辨率更高的方向发展.     

中央电视台二维有线传输索道摄像系统介绍

为了克服常规索道摄像机信号通过无线传输容易受到干扰的问题,中央电视台启动了有线索道系统的研发工作。经过近两年的论证、设计、制造、集成及软件开发等过程,最终完成了二维有线传输索道摄像机系统。本文对项目的立项背景做了阐述,对系统的原理及各主要部分进行了详细的介绍,对研发过程中遇到的难点也进行了说明,最后对系统投入使用的情况及取得的成果做了展示。