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介绍了工件在拉深过程中 ,由于坯料在外力的压应力作用下所产生失稳而引发起皱的原因 ,并就防止起皱提出了增加压边力、拉应力等相应措施 相似文献
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土壤环境背景值图件是一种综合信息载体。本文通过对环境背景值影响因素的综合分析、主要影响因素聚类分析、聚类一判别分级等步骤,选择和确定了制图单元。按多元统计单元进行编图,其表达更为清晰、科学、准确。 相似文献
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五边到场交通态势安全评估研究 总被引:1,自引:0,他引:1
为提高五边到场交通运行的安全性,基于客观、合理的评估五边到场交通态势的重要性,探讨空中交通复杂性在五边到场交通态势评估中的应用,并利用基于五边到场交通的复杂性图示方法,画出五边到场交通复杂性图,通过对复杂性图的分析来描述当前五边到场交通态势的安全特征,包括航空器与航空器之间发生冲突的可能性以及到场航空器允许插入五边的时间和位置等。结果表明:五边到场交通复杂性图能客观、准确地评估五边到场交通中航空器与航空器之间潜在的冲突大小,通过五边到场交通复杂性来对五边到场交通态势进行安全性评估是可行的。 相似文献
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用安全学科的观点 ,对冷拔内模进行宏观痕迹分析和磨损失效模式的确定 ,并结合摩擦学精典的磨损理论 ,对冷拔内模进行微观磨损机理分析 ,从而为提高冷拔内模使用可靠性提供了理论依据和有效措施。 相似文献
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During 28–29, September 2005, water was drawn from Hanjiang River and Houguan Lake to the Yangzi River via Sanjiao Lake and
Nantaizi Lake in Wuhan in order to provide favorable conditions for ecosystem restoration. To evaluate the feasibility and validity of
drawing water as a means of ecosystem restoration, zooplankton populations were studied 3 times (before, immediately after finishing
and a month after drawing water) at seven locations from 27 Sept. 2005 to 2 Nov. 2005. Water quality in the lakes was mostly
improved and zooplankton species richness decreased as soon as drawing water had finished but increased a month after drawing
water. Zooplankton density and biomass was reduced in the lakes by drawing water but was increased at the entrance to Sanjiao Lake
because of landform geometry change. Before drawing water, most species in Sanjiao Lake e.g., Brachionus sp. and Keratella sp. were
tolerant of contamination. After drawing water oligotrophic-prone species such as Lecane ludwigii and Gastropus stylifer emerged.
We conclude that drawing water could be important for improving water quality and favour ecosystem restoration. Dilution of nutrient
concentrations may be an important role in the e ect. 相似文献