The servo control method of a virtual microassemble system integrated CAD model

虚拟技术可克服微装配中显微视觉系统小景深、小视场的问题,但构造虚拟场景时,数据量大、效率低.利用微器件设计时的CAD数据,可减小构造虚拟环境的数据量、提高效率,能够使构造出的场景更精确.利用显微镜聚焦———失焦理论并借助于器件CAD模型构造虚拟环境;将获得的深度信息集成在伺服控制方程中.通过这些方法,可进行复杂路径的规划,完成三维微装配任务,仿真和实验结果均表明上述方法是可行的.Virtual microassembly technology can avoid the problem that the focal depth and the viewing field of microscope are too small.But when building virtual scene there are too many assembly environment data and the efficiency is lower.Using the CAD data produced by the micro-parts can reduce the amount of the environment data and improve efficiency.The virtual environment is constructed using the focus-defocus theory of microscope and the CAD model,and the depth information of microscope is integrated in the servo control equation.By these methods the complex path can be programmed and the complicated micro-assemble task can be completed.The simulation and the experimentation indicate that these methods are feasible.国家自然科学基金资助项目(50275078

Observation results by the TAMA300 detector on gravitational wave bursts from stellar-core collapses

We present data-analysis schemes and results of observations with the TAMA300 gravitational-wave detector, targeting burst signals from stellar-core collapse events. In analyses for burst gravitational waves, the detection and fake-reduction schemes are different from well-investigated ones for a chirp-wave analysis, because precise waveform templates are not available. We used an excess-power filter for the extraction of gravitational-wave candidates, and developed two methods for the reduction of fake events caused by non-stationary noises of the detector. These analysis schemes were applied to real data from the TAMA300 interferometric gravitational wave detector. As a result, fake events were reduced by a factor of about 1000 in the best cases. The resultant event candidates were interpreted from an astronomical viewpoint. We set an upper limit of 2.2x10^3 events/sec on the burst gravitational-wave event rate in our Galaxy with a confidence level of 90%. This work sets a milestone and prospects on the search for burst gravitational waves, by establishing an analysis scheme for the observation data from an interferometric gravitational wave detector

乙烷氧化裂解制乙烯

乙烷氧化裂解制乙烯与传统的热裂解制乙烯相比，变吸附的反应放热反应，降低了能耗。乙烷氧化裂解制乙烯适宜的反应条件：温度８００－８５０℃；原料气停留时间１．０－１．５ｓ；ｎ（Ｃ２Ｈ６）／ｎ（Ｏ２）＝２；惰性气体摩尔分数为５０％－７０％；乙烷转化率可达９３．６％，乙烯选择性为６２．６％，乙烯收率达５８．６％