WBY210型稳定土拌和机液压系统的设计与研究

液压系统是WBY210型稳定土拌和机的重要组成部分,它可以承担和完成拌和机所需的全部功能,准确实现拌和机在各个不同工况时的动作要求。探讨了WBY210型稳定土拌和机的结构组成、工作原理以及整机行走、拌和工作、整机转向、工作装置提升、斗门开闭等液压系统的设计。     

Harmonising sediment criteria of North sea and Rhine river Basin

As a result of convenants between the Port of Rotterdam and the German Chemical Industry, the emissions in the Rhine between Basle (Switzerland) and the Dutch boarder have fallen by more than half in the past fifteen years. Recent studies have concluded that people are nowadays polluting the Rhine more than industry. This places Rotterdam’s involvement with the quality of water and the sediment of the Rhine, port and North Sea in a different perspective. As a medium-sized European municipality, Rotterdam doesn’t want to take on too much, certainly not when cross-border issues such as the quality of the North Sea and the Rhine water are concerned. Rotterdam is now trying to get other organisations to co-operate in solving this problem. A cleaner Rhine, after the success on point sources, can be achieved primarily by reducing the contamination from diffuse sources, over which the port itself has absolutely no control. Rotterdam is the homeport of Mrs. Els Kuijper. She gave a keynote lecture during the SedNet Inaugural Conference, April 22–23, 2002, which forms the basis of this article. Mrs. Kuijper is the vice-mayor and environmental alderman of Rotterdam.     

籼粳杂交稻高效吸收氮素的相关机理研究

通过盆栽和水培实验研究了籼粳杂交稻甬优12（YY-12）、嘉优中科6（JY-6）和常规粳稻秀水134（XS-134）常规供氮（M-N）和低氮（L-N）下分蘖盛期水稻氮素利用效率差异，并初步探讨相关机理机制。结果表明：YY-12和JY-6在两种供氮水平下氮素吸收效率明显大于XS-134。与XS-134相比，YY-12和JY-6根系干物质累积明显增大，加之根孔隙度（POR）较大，使其根系径向泌氧量（ROL）明显增加。从而很可能造成YY-12和JY-6根际土壤氨氧化菌（AOB）数量和硝化强度明显增加；使YY-12和JY-6根际土壤矿质氮含量明显大于XS134。相关分析表明根际土壤矿质氮含量与水稻氮素吸收效率极显著正相关。因此，YY-12和JY-6氮素吸收效率高很可能与其种植使根际土壤硝化强度增加和有机氮矿化加剧紧密相关。另外，与M-N处理相比，YY-12和YY-6氮素吸收效率在L-N水平下明显增加，而XS-134无明显差异。主要原因为：与M-N相比，YY-12和YY-6在L-N水平下根系干物质累积和POR增加比例均大于XS-134；ROL和根际土壤硝化强度，以及根际土壤矿质氮含量下降比例小于XS-134。