排序方式: 共有55条查询结果,搜索用时 0 毫秒
41.
此文利用上限法建立带毂直齿圆柱齿轮精锻过程的数学模型,并利用该模型对带毂直齿圆柱齿轮精锻过程中坯料外形尺寸和力一行程曲线进行了计算机模拟。对所得结果作了实验校核。实验结果与模拟结果吻合得较好,证明此文所建立的数学模型和模拟方法是可行的。 相似文献
42.
43.
探讨了几种圆柱齿轮冷锻成形技术 ,对圆柱齿轮冷锻特性进行了分析 ,并运用系统的观点对提高冷锻圆柱齿轮的轮齿精度做了探讨 相似文献
44.
电动助力转向装置是汽车上一种新的助力转向系统装置 ,近年来在国内外发展迅速 ,由于它采用了可编程电子控制装置 ,在带来灵活性的同时也存在着安全隐患。在分析这种产品特殊性的基础上 ,笔者结合电子控制装置的特点 ,指出了事关安全性的因素 ,提出了处理安全性的措施 ,并讨论了几个事关安全性的具体问题。研究结果表明 :现有标准不能够满足电动助力转向装置安全性的需要 ;并提出了对电动助力转向装置进行安全性测评的思想。研究工作对电动助力转向装置的开发以及评价具有参考意义。 相似文献
45.
Sustainability has become a major focus area within forest products industry. The European operational environment and national environmental steering in EU member states highlight the importance of sustainable development and the development of associated new management approaches to promote sustainability. This article reviews some key elements of sustainability management, covering examples of both Finnish forest products industry initiatives and public environmental steering at the European level. An assessment is made of the current situation and an outline of a future outlook for sustainability management, with special emphasis on bridging the gap between industry initiatives and environmental steering in the form of legislation, policies and strategies at the EU level.This study applied a hybrid approach comprising a review of EU sustainability initiatives, a policy and legal review and a questionnaire survey of forest industry actors. The results of the future outlook indicate that energy efficiency is perceived to be the most important focus area in addition to e.g. environmental and waste management and recycling. Less than half of the companies aim at applying sustainability management. Life-cycle management is also considered to be important whereas product-based approaches, climate change and local industrial symbiosis receive very little attention. All responding companies aim to integrate the principles of sustainability into their operations and most companies consider that life-cycle thinking, management and assessment are useful for them. Energy efficiency is identified as the most important focus area with energy and materials efficiency seen as the most crucial factors for the achievement of responsible competitive advantage and building of sustainable value-added. The findings indicate that sustainability and life-cycle management are not receiving enough management focus at the moment and neither is the industry receiving enough guidance at either the EU level or via national steering and regulatory frameworks. 相似文献
46.
刘文林 《中国特种设备安全》2013,(12):27-29
安全钳是电梯设备的重要安全装置,是增强电梯安全性的重要组成部分。现行的国标GB7588—2005和欧洲标准EN81中只对电梯制动的平均减速度做了规定。本文应用计算软件辅助计算,对电梯的安全钳制动过程进行定量模拟,以更好对电梯安全钳制动过程有深入的了解,并对更好地认识安全钳的工作过程有重要意义。 相似文献
47.
48.
Path Dependencies and Path Change in Complex Fields of Action: Climate Adaptation Policies in Germany in the Realm of Flood Risk Management 总被引:1,自引:0,他引:1
The spatial and temporal repercussions of climate change are of an extremely complex nature. Coping with climate change is,
first and foremost, a challenge to political decision making and, considering the long-term effects of the climate system,
to planning. However, there have never been more doubts that the political-administrative system is able to meet these requirements.
Although much evidence has been put forward in favor of such skepticism, sometimes, it is dangerous to overstate the existing
limits. Drawing on two case studies in the area of flood risk management in Germany, the article illustrates how and why significant
path change came about. In both cases, the state proved to still being a pivotal actor, due to a number of functions that
cannot be assumed by other actors. However, other actor groups—such as actors from science, the media, NGOs, and citizen groups—play
a significant role as well by providing relevant expertise and influencing the public discourse, thus mobilizing significant
political pressure. 相似文献
49.
目的 研究车辆转向桥前梁在受损情况下的极限承载规律。方法 对转向桥前梁在破片高速侵彻作用下的破坏结果进行数值模拟研究,确定破片正侵彻转向桥前梁不同部位时的侵彻弹道。对含侵彻缺陷的转向桥前梁承受垂直载荷能力进行数值模拟研究。结果 确定了破片正侵彻转向桥前梁不同部位时的侵彻弹道约为圆形通孔。对于直径为1 cm的圆孔缺陷,当位于非易损区时,前梁达到极限承载时在易损区发生断裂,其极限承载能力约为无缺陷时70%;位于易损区时,前梁达到极限承载时裂纹会经过圆孔,其极限承载能力约为无缺陷时60%。以某典型车辆为例,计算得到前梁易损区圆孔缺陷直径超过1.8 cm时,前梁会在车辆的自重下发生塑性屈服。结论 转向桥前梁部件极限承载能力受缺陷尺寸和位置的影响,缺陷尺寸越大,前梁极限承载能力越小。当缺陷位于易损区时,前梁极限承载能力比同尺寸缺陷位于非易损区时更小。该结果可为转向桥功能失效分析提供参考依据。 相似文献
50.
张旭明 《中国安全生产科学技术》2012,(Z1):190-193
介绍了一种新型自散热型缓降器。该新型自散热型缓降器是一种往复式高楼避难自救逃生器械,缓降器采用行星齿轮传动,工作时通过缓降绳索带动主机内的行星轮减速机构运转与摩擦轮毂内的摩擦块产生摩擦作用,保证使用者依靠自重始终保持一定速度平衡、安全缓降至地面,无需其他辅助动力,同时具备自散热功能,是高楼安全逃生产品之一。 相似文献