排序方式: 共有5条查询结果,搜索用时 0 毫秒
1
1.
“提起董志塬,美名天下传,塬大土地肥,富饶赛秦川”。这是甘肃人民对董志塬的赞歌。董志塬位于甘肃省东部,庆陽,宁县境内的泾河中游,东临马连河,西界蒲河,南至泾河,北到铜川桥,东西宽20公里,南北长115公里,总面积2,300平 相似文献
2.
3.
一自去冬兴起农業生产高潮以来,全省人民在党中央和省委以及各級党委的正确領导下,發揮了冲天干勁,水利、水土保持工作取得了空前的巨大成績。一年来共計新修水地1,800万亩,控制水土流失面积51,350平方公里,完成土、石方23亿多公方,使用劳动工日5亿5千多个(包括一部份附帶劳动),运动高潮时每天投水利、水土保持的劳动大軍340万人,并日新月異創造出多种多样的新式工具,提高劳动效率几倍、十几倍甚至几十倍、几百倍。現在全省已有水地3,025万亩,占耕地面积的50%,按农業人口平均,每人有水地二亩七分,已控制水土流失面积82,280平 相似文献
4.
5.
The new model for parallel repairable system is introduced,and it is based on the practice problems of maintenance and the idea of Ion-Channel modeling.In the new model,repair times that are sufficiently short (less than some critical value) do not result in system failure,and such a repair interval is omitted from the downtime record.Usually,the underlying process is Markov process if the durations of working and repair time have the negative-exponential distributions,but the new system has not the Markov properties,which is worth to study.The reliability indexes such as instantaneous availability and steady-state availabilities for the new system are given through probability analysis.A numerical example is given to illustrate the results. 相似文献
1