师法自然的盆景

大自然是美好的.深居闹市的人们,享受不到,也就更加向往.他们通过人工的手法,把锦绣山川缩小为一个公园,缩小为一个庭院,或者再缩小一些,这就产生了盆景的艺术.     

渝东北次增长极及其城乡统筹最优路径研究

运用钱纳里工业阶段论与钱纳里和塞尔昆的多国模型对城市化状态与产业结构的验证表明,渝东北总体还处于初级产品生产阶段,只能定位于组团式城市群之间的次增长极。结合城乡统筹必要性与国际经验,发现培育产业集群是渝东北次增长极破解产业空虚与实现城乡统筹的最优路径。     

基于差分方法的FAST圈梁 变形监测研究

针对我国500 m口径球面射电望远镜(FAST)的圈梁变形监测,提出了位置差分数学模型,并进行了数据分析和验证。采用基于差分方法的FAST圈梁变形监测,使得圈梁的变形监测数据更加可靠,并为今后FAST使用差分测量方法提供数据参考。     

TPS based on trilateration for the feed measurement of FAST

Five-hundred-meter Aperture Spherical radio Telescope( FAST) is the largest sensitive single dish radio telescope in the world,in which the control and measurement of the feed is one crucial section of the FAST control system. Trilateration is presented to obtain three-dimensional coordinate for tracking feed focus cabin. Every three total stations chase prism movement to be attached on feed focus cabin and the prism position is determined from the measured distances based on the principle of trilateration. Therefore,feed position is determined from three prisms on the focus cabin. This study is to assess the accuracy and reliability of trilateration calculation on tracking focus cabin of FAST. Different arrangement of total stations on trilateration is theoretically studied. Through experiment,the proposed method shows that the accuracy is better than that of the polar coordinate measurement. The average root mean square error is lower than 0. 6 mm,which is found to have high accuracy and reliability.