碳纤维复合材料在摩托车上的应用

碳纤维复合材料具有优良的综合性能,在国民经济和国防建设中发挥着非常重要的作用.将其用于制作摩托车零部件,在工艺上是成熟的,不仅可以提高产品的质量,而且可以增强企业的品牌效应.     

Airline emission charges: Effects on airfares,service quality,and aircraft design

This paper explores the effect of airline emissions charges on airfares, airline service quality, aircraft design features, and network structure, using a detailed and realistic theoretical model of competing duopoly airlines. These impacts are derived by analyzing the effects of an increase in the effective price of fuel, which is the path by which emissions charges will alter airline choices. The results show that emission charges will raise fares, reduce flight frequency, increase load factors, and raise aircraft fuel efficiency, while having no effect on aircraft size. Given that these adjustments occur in response to the treatment of an emissions externality that is currently unaddressed, they represent efficient changes that move society closer to a social optimum.     

Location of bus garages

The location of bus garages is a complex issue that has received recent attention in the literature. Given a bus system, the number of bus garages and their locations depend on garage cost, deadheading cost and environmental impacts. An approximate analytical model is used to determine the number of bus garages that minimizes the above costs. The concept of a slowly varying density of bus-route origins (hence deadheads) per unit area is used to model deadheading costs. The increased deadheading caused by breakdowns and accidents is also considered. The garage cost is modeled as a function of the number of buses stored. A closed-form solution is obtained for the optimal density of garages, when the garage cost function is linear. The actual locations of garages and the allocations of buses to the garages are found using a discrete space location-allocation model formulated so as to consider the environmental impact associated with buses deadheading through populated neighborhoods.     

Influence of vehicular traffic on urban air quality – A case study of Hyderabad,India

In the present study, impact of vehicular traffic emissions on black carbon aerosol mass concentration, trace gases and ground reaching solar radiation were analyzed during nationwide truck strike of 5–12 January, 2009 over urban environment of Hyderabad, India. A significant reduction of about 57%, 60%, 40% and 50% was observed in black carbon, particulate matter, carbon monoxide and ozone respectively during nationwide truck strike period. Results of the study are important for source apportionment of pollutants as the strike created natural laboratory for studying the impact of diesel operated trucks on urban air quality.     

海洋工程用钢疲劳寿命与CTOD值关系的研究

通过对钻井平台上所用高强钢EQ70进行了韧度和疲劳性能的试验研究,得出了反映其韧度指标的裂纹尖端张开位移(CTOD)值和不同交变载荷下疲劳寿命值呈近似的线性关系.在应力幅值ΔP一定的情况下,疲劳寿命值N随着CTOD值的增大而增大,并且在高应力幅的时候,对数疲劳寿命和CTOD值有比较好的线性关系,最后还从微观意义上解释了产生这种关系的原因.     

新一代机车控制柜功能测试台

描述了一种用于电力机车电子柜和微机柜进行系统级功能测试的试验设备,对其功能、系统组成和软硬件设计特点进行了说明.该测试台已完成样机试验,在测试精度和响应速度方面有很大提升.     

Development of hot stamped center pillar using form die with channel type indirect blank holder

The hot stamping process has been used in the automotive industry to reduce the weight of the body-in-white and to increase passenger safety via improved crashworthiness. However, defects such as fracture and wrinkle occur when hot stamping is performed using a conventional drawing or forming method. In this study, a channel-type indirect blank holder (CIBH) is proposed to develop a high-strength center pillar in form-type hot stamping, so that the aforementioned drawbacks are overcome. This type of blank holder plays an important role in reducing severe wrinkling at the flange; such wrinkling leads to folding after the completion of form-type hot-stamping. First, we investigated the effect of the channel shape on the indirect blank holding force by using a simplified two-dimensional plane-strain stamping process. Second, we selected the slope angle and corner radius of the channel as the main shape parameters by finite element analysis and artificial neural network (ANN). It is known that fracture at the hot formed wall and wrinkle at the flange are significantly affected by the slope angle of the channel, and the appropriate value for eliminating fracture and wrinkle is determined to be 99°. By performing hot stamping using a form die with the selected channel, we can manufacture a high-strength center pillar without wrinkle and fracture.     

扑朔迷离的台湾潜艇发展

忙里忙外欲购新艇 1999年6月以来,台湾"驻荷兰台北经济文化办事处"比以往格外繁忙,办事处的"全权代表"更是东奔西走、上窜下跳.他们究竟在忙碌什么?为何这位"全权代表"要亲自出马,四处活动?要了解个中原委,还得从"全权代表"的不凡身世说起.     

浅埋暗挖平顶直墙大断面隧道施工变形控制

结合北京地铁八号线安德里北街站1号风道工程,对平顶直墙大断面隧道在浅埋暗挖法施工条件下的变形及其控制措施进行分析.采用有限元分析软件ANSYS分别对2种支护方案进行模拟分析.方案一：采用格栅钢架、钢筋网加喷射混凝土的初期支护措施；方案二：在方案一基础上加设大管棚和小导管注浆超前支护措施.另外,还对模拟结果与现场监测数据进行对比分析.通过分析得出：采用方案二的支护措施施工浅埋暗挖平顶直墙大断面隧道,可以控制变形量值在要求的范围内,达到安全施工的目的.     

RECENT DEVELOPMENT OF PROCESS SIMULATION AND ITS APPLICATIONS TO MANUFACTURING PROCESSES

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