ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

Since the beginning of the new century, the research on the field observation and test equipment has been developed, and many important results have been achieved. To overcome the shortcomings and deficiencies of the current test equipment, improve the level of soil erosion theory, scientifically prevent and control soil erosion, developing more advanced and practical soil erosion test equipment has a great significance. For the problems of measuring accuracy of automatic sand sampler and sand collection efficiency affected by strong wind interference, a shunthedging and multistage expansion combined reducing velocity method was proposed, a shunthedging and multistage expansion combined automatic sand sampler was designed, design principle of sand separator and data wireless acquisition system were expounded, and a test and analysis on reducing velocity and separation performance of sand separator, anti strong wind interference performance and collection efficiency of sand sampler were carried out. The results showed that shunthedging and multistage expansion combined automatic sand sampler had anti strong wind interference performance and it could collect data in realtime, continuously and in a long distance wireless. The starting wind speed of free rotation was 4.23m/s, equal dynamic property was 92.94%, average sand collection efficiency was 90.42%, when wind speed was less than 18m/s, as long as soil samples which particle was greater than 55.36μm entered sand sampler, can be fully collected, power supply battery life of data wireless acquisition system was up to 31h. The signal transmission distance was 208.51m without obstacles, which can well meet the automatic observation need for soil erosion mass.