相邻道瑞雷波法及在防渗墙强度检测中的应用

相邻道瑞雷波法是首先从共炮点记录中采用τ～p变换法分离出瑞雷波,然后采用相邻道计算频散曲线,进而通过反演获取横波速度及物性参数.从而消除当前所采用的多道获取频散曲线方法所存在的平均效应的影响,提高瑞雷波法的纵、横向分辨率和无损检测精度,以及拓宽瑞雷波法的应用范围.通过理论模型记录对面波的分离计算,以及采用该方法对某槽孔防渗墙抗压强度检测的实例应用,说明了理论方法的正确性、相邻道瑞雷波法检测防渗墙强度的可行性和有效性,获得了良好的应用效果.     

Estimating seat belt effectiveness using matched-pair cohort methods

Using US data for 1986-1998 fatal crashes, we employed matched-pair analysis methods to estimate that the relative risk of death among belted compared with unbelted occupants was 0.39 (95% confidence interval (CI) 0.37-0.41). This differs from relative risk estimates of about 0.55 in studies that used crash data collected prior to 1986. Using 1975-1998 data, we examined and rejected three theories that might explain the difference between our estimate and older estimates: (1) differences in the analysis methods; (2) changes related to car model year; (3) changes in crash characteristics over time. A fourth theory, that the introduction of seat belt laws would induce some survivors to claim belt use when they were not restrained, could explain part of the difference in our estimate and older estimates; but even in states without seat belt laws, from 1986 through 1998, the relative risk estimate was 0.45 (95% CI 0.39-0.52). All of the difference between our estimate and older estimates could be explained by some misclassification of seat belt use. Relative risk estimates would move away from 1, toward their true value, if misclassification of both the belted and unbelted decreased over time, or if the degree of misclassification remained constant, as the prevalence of belt use increased. We conclude that estimates of seat belt effects based upon data prior to 1986 may be biased toward 1 by misclassification.     

排桩支护逆作法在深基坑工程中的应用实践

本文针对韶钢炉卷旋流池工程的结构、地质、环境、工期等特点，介绍了排桩支护逆作法在深基坑工程中的应用技术及其技术保证措施，可为同类型工程提供参考。     

齿带传动的可靠性设计和可靠性优化设计

研究了齿带传动的可靠性设计方法,在保证传动的预期可靠度及其它约束的条件下,以最小体积为目标,建立了齿带传动可靠性优化设计的数学模型,并给出了计算示例。     

中国东部主要盆地天然气富集带形成及分布规律

我国东部油区天然气主要有第三系深凹陷油型热裂解成气、第三系中浅层生物改造热作用成气、古—中生界煤系高演化成气三种主要类型。东部陆相富油盆地内天然气富集带的形成条件主要有：烃源层系内高异常地温场或早期生物改造条件的存在;高热演化烃源岩在中等热演化期没有较显著的排烃史或一次热演化程度不高;聚气构造带为区域拉张背景下的扭压应力环境所形成;各种流体势系统中的相对低势环境以及具有良好的储、盖及保存条件等。     

硅橡胶发泡胶带的研制

介绍了硅橡胶发泡胶带的制备工艺,以及发泡剂,硫化剂用量的影响,确定了胶带的配方及其质量控制标准。     

北京绿隔乡村土地利用演变及其保留村庄的评估与管控研究——以崔各庄乡为例

北京城乡结合部地区自1994年起陆续以绿化隔离带(绿隔)规划、新农村建设、土储拆迁等为政策与项目依托,实施超大城市增长管控与乡村治理,研究其过程中的土地利用演变具有重要意义.对绿隔村庄的相关研究进行了文献综述,并深入介绍了韩国首尔在1980年代集中进行的“绿隔村庄改造”项目,然后以北京市朝阳区崔各庄乡为实证案例.作为主要结论,提出了遴选绿隔内保留村庄的五条标准,包括流动人口与户籍人口比、产业特色、农宅风貌、是否经过新农村改造、近期是否有城市大型项目或专项资金带动拆迁;同时,提出评价与管控保留村庄内建设用地的四项指标,包括土地出租合同的到期年限、建设用地合法性、单位建设用地租金,以及建设用地上的建筑质量;进而根据上述评价结果编制村庄规划,以引导和管控绿隔内保留村庄的建设活动.     

Planet Moon: The Future of Astronaut Activity and Settlement

Ceaseless demographic growth and the depletion of the Earth's natural resources make the colonisation of space an increasingly compelling prospect. Madhu Thangavelu , an expert in the design of complex space projects, including space stations and exploratory missions, and a professor in the Department of Astronautical Engineering at the University of Southern California (USC), explores the possibilities and extreme environmental challenges posed by human settlement of our closest planetary neighbour, the Moon.     

Risk factors for fatal road traffic accidents in Udine, Italy.

In the Province of Udine, Northeast Italy, mortality from road accidents is 37% higher than in the country as a whole. To identify the major risk factors for fatal crashes in this area, we analyzed the Police reports of 10,320 road traffic accidents that occurred from 1991 to 1996. Logistic regression was used to evaluate the association of characteristics of drivers and accidents with accident severity. The risk of involvement in fatal rather than non-fatal accidents was lower among females than among males (odds ratio (OR) = 0.65; 95% confidence interval (95% CI), 0.53-0.80). Compared with subjects < 30 years of age, subjects aged > or = 65 had a significantly increased risk of fatal injury as pedestrians (OR = 10.87; 95% CI, 4.45-26.54), car drivers (OR = 1.85; 95% CI, 1.08-3.18), moped riders (OR = 3.53; 95% CI, 1.42-8.78), and bicycle riders (OR = 7.72; 95% CI, 2.56-23.29). In accidents that occurred from 1:00 to 5:00 h the risk of death was higher than from 6:00 to 11:00 h among pedestrians (OR = 8.88; 95% CI, 2.58-30.52), car drivers (OR = 4.95; 95% CI, 3.09-7.95), motorcycle riders (OR = 13.44; 95%CI, 2.54-71.05) and moped riders (OR = 8.76; 95% CI, 2.42-31.69). Risk of death among pedestrians, car drivers, moped, and bicycle riders was also significantly increased on roads outside the urban center. Driver's injury was strongly associated with lack of use of seat belts (OR = 13.27; 95% CI, 9.39-18.74, for fatal injury; OR = 2.49; 95% CI, 2.17-2.86, for non-fatal injury). Simple interventions focused on protecting the weakest road users and based on law enforcement, behavioral change and environmental modification might result in reducing the significant excess of road traffic accident mortality found in the study area.     

塔里木盆地周缘凹陷带含油气特征及勘探前景

在塔里木盆地周缘发育有8个中、新生代的凹陷,即北部的阳霞、拜城、乌什凹陷,西南的喀什、叶城凹陷,东南的民丰和若羌凹陷,以及东部的英吉苏凹陷。在东部、北部、西南部的5个凹陷中已发现油气田。周缘凹陷带发育以侏罗系为主体的烃源岩、以碎屑岩为主体的多套储盖组合以及多种成因类型的构造圈闭。从已发现油气分布特点看,主要受生烃中心、深大断裂以及构造带等因素控制。以晚期成藏为主的周缘凹陷带具有巨大的勘探潜力,特别是勘探程度很低、尚未获得突破的乌什凹陷及塔东南凹陷带也是不容忽视的勘探领域。