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...     

机前补气(稀薄燃烧)分析研究与理论设计计算

通过机前补气的理论计算和试验数据对比,两者结论基本一致,确定了理论计算的正确性。根据理论推导和理论计算的过程,可以更加清晰地找出提高发动机性能和改善整车排放的方式方法;也拓展了研究稀薄燃烧的方式方法,形成了研究稀薄燃烧的有力补充,为后续研究工作带来了新途径。     

钢丝绳生产工艺中的常规锻打与高级锻打

对于压实类钢丝绳特别是高强度、高韧性、高使用性能的钢丝绳,国内外市场需求量不断增加,应用领域迅速扩张,具有日渐广泛的市场发展前景。该类钢丝绳是目前国内外著名钢丝绳企业竞相开发、研制的产品,也是我国港口装卸、工程施工、煤炭采提、有色金属等行业不断斥资从国外进口的主要的钢丝绳产品。压实类钢丝绳具有较高的技术含量,具有发展成为高端钢丝绳产品的基础条件。     

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.     

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...