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186型螺杆空气压缩机气体调节原理 被引量:1
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作者 党卫中 罗新勇 +2 位作者 刘会林 罗周鹏 陈长清 《物探装备》 2014年第1期10-15,共6页
186型螺杆空气压缩机气体调节系统是空压机的核心部件,它由加载阀、调节阀、进气阀和速度调节器组成。本文介绍了压缩机气体调节系统各个元件的结构组成、工作原理、调节过程。掌握这些基本知识,有助于对186型螺杆空气压缩机加深了解、... 186型螺杆空气压缩机气体调节系统是空压机的核心部件,它由加载阀、调节阀、进气阀和速度调节器组成。本文介绍了压缩机气体调节系统各个元件的结构组成、工作原理、调节过程。掌握这些基本知识,有助于对186型螺杆空气压缩机加深了解、以便正确地使用,及时有效地维护、修理,从而提高空压机的出勤率和使用寿命。 展开更多
关键词 186型螺杆空压机 气体调节系统 结构 原理
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Evaluation of Ecosystem Services Provided by 10 Typical Rice Paddies in China 被引量:8
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作者 肖玉 安凯 +1 位作者 谢高地 鲁春霞 《Journal of Resources and Ecology》 CSCD 2011年第4期328-337,共10页
Based on reference review, this study investigated ecosystem services supported by 10 typical rice paddies in six rice planting regions of China. The services were primary production, gas regulation, nitrogen transfor... Based on reference review, this study investigated ecosystem services supported by 10 typical rice paddies in six rice planting regions of China. The services were primary production, gas regulation, nitrogen transformation, soil organic matter accumulation, and water regulation and flood control. The results indicated that grain production of the 10 rice paddies was between 4.71 and 12.18 t ha^-1 y^-1; straw production was 4.65 to 9.79 t ha^-1 y^-1; gas regulation was calculated to emit O2 ranging from 8.27 to 19.69 t ha^-1 y^-1 and to assimilate greenhouse gases ranging from -2.13 to 19.24 t ha^-1 y^-1 (in CO2 equivalent); nitrogen transformation was estimated as nitrogen input ranging from 209.70 to 513.93 kg N ha^-1 y^-1 and nitrogen output of 112.87 to 332.69 kg N ha^-1 y^-1; soil organic matter accumulation was calculated to be between 0.69 and 4.88 t C ha^-1 y^-1; water regulation was estimated to consume water resources of 19875 m3 ha^-1 y^-1 and to support water resources of 6430 m3 ha^-1 y^-1; and flood control of several of the rice paddies was calculated to be 1500 m3 ha^-1 y^-1. The integrated economic value of ecosystem services of these rice paddies was estimated at USD 8605–21 405 ha^-1 y^-1, of which 74%–89% of the value can be ascribed to ecosystem services outside primary production. The results also indicated that the integrated economic value of the ecosystem services of the 10 rice paddies was higher when nitrogen fertilizer was applied in the range of 275 to 297 kg N ha^-1. Until now, the economic value of the rice paddy ecosystem has been underestimated as only the economic value of grain and straw production was previously calculated. As more and more forest land and grassland is lost to urban and industrial use, cropland and especially rice paddies, will become more ecologically important to society. The economic value of ecosystem services supplied by rice paddies, outside primary production, are worthy of increased research attention. 展开更多
关键词 rice paddy ecosystem services gas regulation soil organic matter accumulation nitrogen transformation
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