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WPJL 60-型卷帘机设计 总被引:1,自引:0,他引:1
崔永汉 《延边大学农学学报》2007,29(3):213-217
针对温室大棚用户的实际情况,设计一种WPJL 60-型卷帘机,并对关键结构进行运动分析与受力分析,对其主要结构的技术参数进行分析与计算,以完善机器结构和工作原理. 相似文献
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The static stability of a tailings dam is analyzed with a finite element approach, which takes into account the effect of plastic deformation, temperature, saturation and void ratio on the properties of soil materials, the effect of water and soil interaction and the extended Mohr-Coulomb failure criterion. The concept of yield approaching degree is introduced, which is defined as the ratio of the existing equivalent stress to the yield stress taking into account the effects of different influencing factors. The response of the tailing dam subjected to the coupled saturated/unsaturated seepage and deformation is simulated, considering that the dry beach is 100-meter long and the starter dam is jammed, respectively. The important indexes such as the deformation and the phreatic surface of the dam are obtained. The distribution of the yield approaching degree in the whole dam under the given condition is obtained, which can provide not only a general stability assessment of the dam, but also important information to the decision-making for the reinforcement and maintenance of the dam. 相似文献
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With the increasingly economic competition in the World, the audit industry, numerous investors and the enterprises pay more and more attention on the audit of company's sustainable operation. In view of existing situation that the audit on the capacity of sustainable operation attach main importance to the finance of the audited company, in the result, it is difficult to recognize it completely. The model of the balanced scorecard is used, an indicator system that combine company's finance condition and non-finance condition is built in the sustainable operation audit. Basing on the way to process non-dimensional quantities of indicators, the audit use the analytic hierarchy process to determine the weights of the evaluating indicators and take the degree of gray incidence as the evaluation criteria. 相似文献
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通过分析最新的水土保持监测所获得的实地植被调查样方资料,论述了植被自然恢复在开发建设项目中的水土保持作用,并结合监测实践,探讨了植被自然恢对水土保持评价指标的影响。(1)在山西省雨量较为充沛的地区,如果重视保留表土并用之覆盖地表,就能使地面植被得到较大程度的自然恢复,其恢复面积占可绿化面积的比例约达25%。(2)在雨量较多地区的扰动地面,依靠植被自然恢复功能,可使植被盖度在1~2a内达到50%以上,形成初级植被。(3)由于对乔灌木等深根性植物的破坏较为严重,因此,在1~2a时间内,扰动地面上自然恢复所形成的植被一般为草本群落,并不能完全恢复当地的灌草植被、疏林灌草植被。 相似文献
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以水稻为主的种植系统对土壤有机质状况的影响 总被引:1,自引:1,他引:1
XIAO Yong-Lan ZHANG Yang-Zhu HU Rui-Zhi HUANG Yun-Xiang ZHOU Qing YUAN Zheng-Ping YANG Dong-Ping SHU Li 《土壤圈》1997,7(4):349-354
A long-term simulation experiment was carried out to study the effect of rice-based cropping system, green manure and ground-water level on soil organic matter. Soil organic matter content increased when upland soil was puddled and cropped under submerged conditions. Among all treatments, soil organic matter contents in the treatments of rice-rice-flooded fallow in winter (WF) were the highest, those in the treatments of rice-rice-astragalus (WG) came the second, and those in the treatments of rice-rice-rape (WR) were the lowest. At the same rate of green manure application, the degrees of organo-mineral complexing in soils of treatments WG and WR were higher than those of treatment WF. After 9-year rice cultivation, the state of combination of humus in heavy fraction varied with treatments. The relative content of loosely bonded humus decreased in the order of WR > WG > WF, and it correlated significantly with Se availability. 相似文献