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1.
目的研究飞机尾翼结构采用芳纶纤维复合材料的抗鸟撞性能。方法根据芳纶纤维夹芯和芳纶纤维层合板两种飞机尾翼前缘构型,分别建立有限元模型进行仿真计算,分析两种构型鸟撞后的损伤和变形,并对两种构型进行抗鸟撞性能研究试验。结果芳纶夹芯前缘构型前缘凹陷,前梁没有破裂;芳纶层合板前缘构型前缘破裂,前梁有破损。试验结果与仿真分析结果高度吻合。结论芳纶夹芯前缘构型比芳纶层合板前缘构型具有更好的抗鸟撞性能。芳纶纤维层合板构型会造成前缘蒙皮变形过大,前梁腹板破损,导致飞机鸟撞后维修成本较高。 相似文献
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为掌握致酸大气污染物SO2 和NOx 的空间浓度分布,并探讨上述污染物扩散、迁移和传输规律,进而研究其在酸性降水形成过程中的作用,在“八五”期间酸性降水的研究中,针对中国华北地区城市和工业集中以及SO2 和NOx 等酸性大气污染物排放量大的特点,以石家庄及其以东地区为飞行区域,进行了华北地区冬季空中SO2 和NOx 污染特征的航空测量。通过测定发现在华北地区1-5 km 左右的空中存在着SO2 和NOx 高浓度污染空域,同时SO2 存在着高浓度汇集区 相似文献
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在现代化城市建设与发展中,城市轨道交通引起的电磁辐射环境影响,越来越受到公众的关注,越来越受到各级政府的重视.本文以哈尔滨城市轨道交通工程为例,分析本工程的电磁辐射污染源,采用类比方法,预测和评价电磁辐射对环境的影响,提出了电磁辐射防护措施建议. 相似文献
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针对目前我国民用运输机场航空器场内失事应急救援综合演练缺乏有效评估体系的现状,通过对演练过程进行系统分析,构建航空器场内失事应急救援演练评估指标体系,涵盖消防、医疗、公安、媒体应对、运行指挥中心、地服、飞行区7个组织部门的2级指标。结合航空器场内失事救援的业务特点以及指标体系内在逻辑,设计相应的评估方法,对开展的航空器场内失事应急演练进行评估;最后,以国内2个机场的相关应急演练过程为典型示例,进行应用分析。研究结果表明:构建的演练评估指标体系及评估方法能较好地应用于实际应急演练过程,进而在演练评估结果和建议的基础上,实现应急演练的持续改进。 相似文献
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Reverse logistics (RL) has been applied in many industries and sectors since its conception. Unlike forward logistics, retracing consumer goods from the point of consumption to the point of inception is not a well-studied process. It involves many uncertainties such as time, quality and quantity of returns. The returned products can be remanufactured, have parts harvested, or be disposed safely. It is important to implement these activities in a cost-effective manner. The aim of this research is to measure the performance of the RL enterprise with the help of an agent-based simulation model. The major entities in the RL network are considered as Agents that can act independently. There are several different agents: collector agent, sorting-cum-reuse agent, remanufacturing agent, recycler agent, supplier agent and distributor agent. The individual performances of the agents are measured and recommendations are given to improve their performance, leading to the enhancement of the total performance of the RL enterprise. The approach is applied to a case study involving cell phone remanufacturing. 相似文献
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Assessing field vulnerability to phosphorus loss in Beijing agricultural area
using Revised Field Phosphorus Ranking Scheme 总被引:1,自引:0,他引:1
Guanting Reservoir,one of the drinking water supply sources of Beijing,suffers from water eutrophication.It is mainly supplied by Guishui River.Thus,to investigate the reasons of phosphorus(P)loss and improve the P management strategies in Guishui River watershed are important for the safety of drinking water in this region.In this study,a Revised Field P Ranking Scheme(PRS)was developed to reflect the field vulnerability of P loss at the field scale based on the Field PRS.In this new scheme,six factors are included, and each one was assigned a relative weight and a determination method.The affecting factors were classified into transport factors and source factors,and,the standards of environmental quality on surface water and soil erosion classification and degradation of the China were used in this scheme.By the new scheme,thirty-four fields in the Guishui River were categorized as"low","medium"or"high"potential for P loss into the runoff.The results showed that the P loss risks of orchard and vegetable fields were higher than that of corn and soybean fields.The source factors were the main factors to affect P loss from the study area.In the study area,controlling P input and improving P usage efficiency are critical to decrease P loss.Based on the results,it was suggested that more attention should be paid on the fields of vegetable and orchard since they have extremely high usage rate of P and high soil test of E Compared with P surplus by field measurements,the Revised Field PRS was more suitable for reflecting the characteristics of fields,and had higher potential capacity to identify critical source areas of P loss than PRS. 相似文献