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371.
上海国际航运中心建设目标和战略举措研究 总被引:1,自引:1,他引:0
沈玉芳 《长江流域资源与环境》1999,8(4):345-352
国际航运中心是指以国际航运、国际贸易、国际金融为主要依托的港口城市,也是国际贸易、全球生产分工、商品流通和资源分配的枢纽。从21世纪中国经济发展的需要、上海实现“一个龙头、三个中心”的实际要求以及国际航运市场的竞争态势出发,上海必须在21世纪初建设成为国际航运中心。 相似文献
372.
James Damsere-Derry Beth E. Ebel Charles N. Mock Francis Afukaar Peter Donkor Thomas Ojo Kalowole 《Traffic injury prevention》2019,20(3):336-342
Objectives: Each year, pedestrian injuries constitute over 40% of all road casualty deaths and up to 60% of all urban road casualty deaths in Ghana. This is as a result of the overwhelming dependence on walking as a mode of transport in an environment where there are high vehicular speeds and inadequate pedestrian facilities. The objectives of this research were to establish the (1) impact of traffic calming measures on vehicle speeds and (2) association between traffic calming measures and pedestrian injury severity in built-up areas in Ghana.Method: Vehicle speeds were unobtrusively measured in 38 selected settlements, including 19 with traffic calming schemes and 19 without. The study design used in this research was a matched case–control. A regression analysis compared case and control casualties using a conditional logistic regression.Results: Generally, the mean vehicle speeds and the proportion of vehicles exceeding the 50?km/h speed limit were significantly lower in settlements that have traffic calming measures compared to towns without any traffic calming measures. Additionally, the proportion of motorists who exceeded the speed limit was 30% or less in settlements that have traffic calming devices and the proportion who exceeded the speed limit was 60% or more in towns without any traffic calming measures. The odds of pedestrian fatality was significantly higher in settlements that have no traffic calming devices compared to those that have (odds ratio [OR]?=?1.98; 95% confidence interval, 1.09–4.43). The protective effects of a traffic calming scheme that has a speed table was notably higher than those where there were no speed tables.Conclusion: It was clearly evident that traffic calming devices reduce vehicular speeds and, thus, the incidence and severity of pedestrian injuries in built-up areas in Ghana. However, the fact that they are deployed on arterial roads is increasingly becoming a road safety concern. Given the emerging safety challenges associated with speed calming measures, we recommend that their use be restricted to residential streets but not on arterial roads. Long-term solutions for improving pedestrian safety proposed herein include bypassing settlements along the highways to reduce pedestrians’ exposure to traffic collisions and adopting a modern way of enforcement such as evidence-based laser monitoring in conjunction with a punishment regime that utilizes the demerit points system. 相似文献
373.
为研究大同矿区综放开采的覆岩运动特征,以同忻矿8105工作面为研究对象,运用关键层理论确定了同忻矿8105工作面关键层分布,采用理论分析、相似材料模拟方法对压力拱的演化规律进行了研究,并结合现场监测数据对研究结果进行了验证。结果表明,在同忻矿双系煤层开采条件下,关键层破断影响着压力拱的发展高度,沿工作面推进方向,压力拱的失稳步距为283~330 m。拱脚位置在工作面前方40~55 m,压力拱承载着大部分的覆岩载荷,一旦发生失稳破坏,会造成石炭系岩层与侏罗系采空区连通,引起工作面强矿压显现。 相似文献
374.
375.
介绍了核电人因管理的发展历史,在国际核电业界防人因失误管理标准的基础上,结合部分国内外核电厂的防人因失误管理实践,探讨了影响核电厂人因管理的模型,对业界普遍存疑的概念进行了辨析,分析了影响人因管理有效性的关键因素,提出了提高核电厂防人因失误管理有效性的建议以及良好实践。 相似文献
376.
Mapping lightning/human-caused wildfires occurrence under ignition point location uncertainty 总被引:1,自引:0,他引:1
Fire managers need to study fire history in terms of occurrence in order to understand and model the spatial distribution of the causes of ignition. Fire atlases are useful open sources of information, recording each single fire event by means of its geographical position. In such cases the fire event is considered as point-based, rather than area-based data, completely losing its surface nature. Thus, an accurate method is needed to estimate continuous density surfaces from ignition points where location is affected by a certain degree of uncertainty. Recently, the fire scientific community has focused its attention on the kernel density interpolation technique in order to convert point-based data into continuous surface or surface-data. The kernel density technique needs a priori setting of smoothing parameters, such as the bandwidth size. Up to now, the bandwidth size was often based on subjective choices still needing expert knowledge, eventually supported by empirical decisions, thus leading to serious uncertainties. Nonetheless, a geostatistical model able to describe the point concentration and consequently the clustering degree is required. This paper tries to solve such issues by implementing the kernel density adaptive mode. Lightning/human-caused fires occurrence was investigated in the region of Aragón's autonomy over 19 years (1983–2001) using 3428 and 4195 ignition points respectively for the two causes of fire origin. An analytical calibration procedure was implemented to select the most reliable density surfaces to reduce under/over-density estimation, overcoming the current drawbacks to define it by visual inspection or personal interpretation. Besides, ignition point location uncertainty was investigated to check the sensitivity of the proposed model. The different concentration degree and the dissimilar spatial pattern of the two datasets, allow testing the proposed calibration methodology under several conditions. After having discovered the slight sensitivity of the model to the exact point position, the obtained density surfaces for the two causes were combined to discover hotspot areas and spatial patterns of the two causes. Evident differences in spatial location of the origin causes were noted and described. The general trend follows the geographical features and the human activity of the study areas. The proposed technique should be promising to support decision-making in wildfire prevention actions, because of the occurrence map can be used as a response variable in fire risk predicting models. 相似文献
377.
2005年7至2007年4月,采用直接记数法和"GPS"技术定位监测对洞庭湖湿地珍稀濒危保护鸟类资源及其环境进行调查。结果表明:洞庭湖湿地珍稀濒危保护鸟类有218种,隶属于16目46科。其中古北界鸟类占优势,有118种,东洋界鸟类54,广布种鸟类46种。冬候鸟为主体,有118种,留鸟40种,夏侯鸟35种,旅鸟25种。按生态类群分,游禽45种、涉禽69种、陆禽3种、猛禽22种、攀禽11种、鸣禽68种;该湿地有国家Ⅰ级重点保护鸟类7种、Ⅱ级重点保护鸟类43种,国际湿地公约名录中的鸟类37种。洞庭湖湿地珍稀濒危保护鸟类群落Shannon-Wiener多样性指数和Pielou均匀性指数分别为4.489 7和0.576 5。 相似文献
378.
中国葡萄属(VitisL.)分类研究 总被引:7,自引:0,他引:7
报导了中国葡萄属植物现存全部种类的分类处理结果,这些结果是在对植物野外和栽培观察及标本室研究基础上获得的;标本室的研究除了中国之外还包括参阅欧洲的一些著名标本馆内早期植物学家鉴定名称所依据的标本,因而所有种类的确定较之过去更为可靠.文中发表了一些新分类群和新组合,给出了鉴定种类的检索表. 相似文献
379.
将灰色模型引入水环境质量评价中,通过对某个时间段内污染物原始监测数据的灰色处理,从动态演变中找出关键因子,客观地判定各污染因子所起的作用,并对各因子在下一个时间段的发展趋势作出判断,增加了评价的准确性。经过实例运用分析表明,该方法物理意义明确,简便易用。 相似文献
380.
申静 《安全.健康和环境》2020,(5):26-28
通过识别和分析制苯生产装置的职业病危害因素,确定职业病危害的关键控制点,提出了防护措施对策,应重点加强作业人员接触有毒物质苯、硫化氢关键控制点的职业卫生管理。 相似文献