我国汽车零部件产业竞争形势与战略选择

目前我国汽车零部件在全球产业链价值分工中处于低端位置,国内竞争也从单纯的产品与技术竞争发展到以整车为核心的零部件配套体系间的竞争。我国汽车零部件产业目前处在投资导向的初级阶段,存在3个核心问题:一是核心技术对外依赖严重;二是立足本土文化特征的供应链协作模式尚未形成;三是自主零部件的发展缺少自主品牌整车的需求拉动。新形势下我国汽车零部件应该选择"开放的大国图强"发展模式。     

成都市轨道交通市域快线技术创新与实践

成都市轨道交通18号线是按"中心穿越、串城连接、快慢运行、互联融合"理念实施的全国首条最高运行速度为140～160 k m/h,兼顾中心城区、市域及机场客流,集"快慢组合、共线运营"等多种运营组织模式于一体的8A编组、AC25kV供电的复合功能快线.文章从其运营模式、线路敷设、车辆选型及升级、供电制式及电磁干扰、空气动...     

摩托车机前补气(稀薄燃烧)分析研究与国Ⅲ应对(2)

新型油气分离器焊接工艺:把分离器上螺柱拧入油气分离器本体,分离器连接管插入油气分离器本体并焊接牢固,再把已经组合好的分离器部件焊接在油箱内部加油口附近的前上方最高位置,最后装上分离器浮子体,拧上分离器下螺柱,即完成油气分离器的焊接与装配。分离器浮子体为非金属件,密度小于燃油,上部为半个圆球,下部为圆柱,圆柱周边有均分的4个矩形凹槽与底面的十字矩形凹槽相通。工作原理:把油气分离器焊接在油箱内部加油口附近     

基于梁格法的某斜交变宽连续箱梁桥荷载试验分析

基于梁格理论建立某斜交变宽连续箱梁桥的空间梁格模型,计算分析设计活载及试验荷载作用下结构的静动力响应,基于模型计算结果指导该桥的现场荷载试验,并据现场试验结果评价箱梁结构的工作状态。     

容差分配技术在轿车车身设计中的应用研究

阐明了容差分配理论,论述了容差分配技术在轿车车身设计中的应用,并将其应用到某车型开发的工程实例中.在满足产品装配精度和技术要求的前提下,制定出了较宽松的公差,从而降低了开发成本,减少了整改次数,缩短了产品开发周期.     

Prenatal assessment of normal fetal pulmonary grey-scale and lung volume by three-dimensional ultrasonography

Objective To quantitatively analyze the fetal lung echo and right lung volume in the third trimester by real-time three-dimensional ultrasound (3-D US) and evaluate the feasibility of fetal lung maturity. Methods A total of 732 women with normal singleton pregnancies between 28 and 42 weeks of gestation underwent ultrasound examination. The 3-D US equipment with a 3.5-5MHz transabdominal transducer was used for the fetal biometric measurement. The echogenicity ratio between fetal lung and liver was compared. The fetal lung volume was calculated by the rotational multiplanar technique for volume measurement (VOCAL). Results The right fetal lung volume increased with the increase of gestational age with a linear positive correlation (r=0.884, P<0.01). After 34 weeks, the echogenicity ratio of fetal lung to liver was more than 1.1. Conclusion The echogenicity of lung/liver and fetal lung volume could be used as normal fetal predictable indicators for fetal lung maturity.     

温州市域铁路线路敷设方式比选研究

市域铁路线路敷设方式比选是市域铁路设计重点之一。本文结合市域铁路建设条件和工程特点，以温州市域铁路南洋大道段线路为例，对地下线和高架线路敷设方式进行了综合比选研究，总结市域铁路线路敷设控制要点，为类似工程设计提供借鉴。     

Analyzing travel time reliability and its influential factors of emergency vehicles with generalized extreme value theory

Travel time reliability is very critical for emergency vehicle (EV) service and operation. The travel time characteristics of EVs are quite different from those of ordinary vehicles (OVs). Although EVs own highest road privilege, they may still experience unexpected delay that results in massive loss to the society. In this study, we employ the generalized extreme value (GEV) theory to measure extremely prolonged travel time and analyze the potential influential factors. First, among three GEV distributions, Weibull distributions are found to be the best distribution model according to several goodness-of-fit tests; a new reliability index is derived to measure travel time reliability. Numerical examples demonstrate the advantages of GEV-based reliability index over variance and percentile value in the applications of EV. This index will be of great practicability in the EV operation performance and reliable route choices. Second, we further investigate the potentially influential factors of EV travel time reliability. Results show that link length and left-turn traffic volume may have an adverse impact on the link reliability while more left-turn lanes may increase the travel time reliability. The influential factor study will help us understand the causes of the EV travel time delay and the differences of travel time reliability between OVs and EVs.     

联合监测评分在高危妊娠监护中的价值

采用羊膜镜检、Ｂ超测羊水量、无负荷试验（ＮＳＴ）、测尿Ｅ／Ｃ值及数胎动５项联合监测评分监护高危妊娠，以期早期诊断胎儿宫内缺氧。结果联合监测诊断胎儿宫内缺氧的准确率为８５．３１％，高于任何单项监测。新生儿娩出后Ａｐｇａｒ评分与联合监测评分呈正相关。以新生儿娩出后Ａｐｇａｒ评分≤７分为窒息标准，判断各项监测的灵敏度，联合监测的灵敏度最高（０．７５）。结合文献对５项联合监测的价值进行了讨论。     

NEW THERAPY FOR PUBIC SYMPHYSIS SEPARATION

ＮＥＷＴＨＥＲＡＰＹＦＯＲＰＵＢＩＣＳＹＭＰＨＹＳＩＳＳＥＰＡＲＡＴＩＯＮ（苟文丽），（屈新中），（赵正航）ＧｏｕＷｅｎｌｉ；ＱｕＸｉｎｚｈｏｎｇ；ＺｈａｏＺｈｅｎｇｈａｎｇ；（ＤｅｐａｔｍｅｎｔｏｆＧｙｎｅｃｏｌｏｇｙａｎｄＯｂｓｔｅｌｒｉｃｓ，Ｆ...