摘要：Thermal performance was the most important factor in the development of borehole heat exchanger utilizing geothermal energy. The thermal performance was affected by many different design parameters, such as configuration type and borehole size of geothermal heat exchanger. These eventually determined the operation and cost efficiency of the geothermal heat exchanger system. The main purpose of this work was to assess the thermal performance of geother^nal heat exchanger with variation of borehole sizes and numbers of U-tubes inside a borehole. For this, a thermal response test rig was established with line-source theory. The thermal response test was performed with in-line variable input heat source. Effective thermal conductivity and thermal resistance were obtained from the measured data. From the measurement, the effective thermal conductivity is found to have similar values for two- pair type （4 U-tubes） and three-pair type （6 U-tubes） borehole heat exchanger systems indicating similar heat transfer ability. Meanwhile, the thermal resistance shows lower value for the three-pair type compared to the two-pair type. Measured data based resistance have lower value compared to computed result from design programs. Overall comparison finds better thermal performance for the three-pair type, however, fluctuating temperature variation indicates complex flow behavior inside the borehole and requires further study on flow characteristics.

摘要：针对雾中能见度探测问题,利用准直镜代替了传统的发射望远镜,透镜组作为激光接收系统,设计了一套小型米散射激光雷达系统,实现了系统的小型化和紧凑化;计算了系统的几何重叠因子,从而得到回波信号的有效提取距离。通过Collis斜率法对室内雾探测结果进行反演获得雾的消光系数和雾中能见度及其他变化特征。实验结果表明:小型米散射系统对雾中能见度的探测是可行的。

摘要：0 Point Ruler是一款表面覆盖着灵敏的压力感应触摸屏的尺子。使用时,只需要用笔尖往尺子上的任何一点轻轻施加压力,感应的到压力的标尺就会将那一个点设定为0刻度,让你可以更灵活更方便的使用标尺测量。0 Point Ruler直尺整体黑色,0刻度会以红色来显示,相当的显眼,而这0可以随意设定位置,尺采用电池驱动,关闭状态下看不到任何的刻度。