DROUGH TREND IN NORTH CHINA IN RECENT FIFTY YEARS

Inrecentseveralyears ,abnormaldroughtoccursinthepartnorthernofChina .Itex ertssomeinfluenceonChina’snationaleconomyandhasarousedwideattentionfromallwalksoflife .Muchresearchindrought wetindexhasbeendonebothathomeandabroad .Theresultcanbeclassifiedintotwocategories:first,droughtindexdirectlyisdefinedbyprecipitationorothermeteorologicalfactors;second ,droughtindexisidentifiedbycalculatinggainingandlos ingoflocalwaterinaccordancewithequationofwaterbalance ,andsomealsoconsidertheim pactofdrought…     

DETERMINING RAINS OF HYDROLOGIC CONSEQUENCE IN CHICAGO FOR FORECASTING APPLICATIONS1

ABSTRACT: Accurate forecasting of heavy rainstorms that affect the Chicago Metropolitan area and lead to the undesirable release of storm runoff into Lake Michigan is a major objective. These releases (overflows) were found to be produced by storm events yielding 2 inches or more in a few hours, although only 24 percent of such ≥ 2-inch storms in the area during 1948-1981 produced overflows. Failure to forecast properly or to be able to react to these 2-inch overflow producing events has occurred most often in the spring and fall, although relatively often in June and July in recent years. These overflows have exhibited an inexplicable trebling during 1972-1981 without an increase in ≥ 2-inch storm events. This type of troublesome storm can be reliably predicted, using a recently developed radar man forecast system for the Chicago area.     

我国荒漠化基本特点及加快荒漠化地区发展的意义

我国是世界上受荒漠化危害最严重的国家之一，荒漠化面积大、分布广、程度重、扩展快，危害深。虽然荒漠化治理取得了一定成就，但只是局部地区得到了治理，荒漠化整体上仍在扩展，这些严重制约了荒漠化地区乃至我国人口、资源与环境的协调发展。荒漠化地区在我国国民经济、社会发展和环境保护等方面具有举足轻重的地位，防治荒漠化对于缩小东西部差距、消除贫困、促进荒漠化地区以及整个中国经济的腾飞具有重要意义。     

Variables influencing growth and morphology of colonies of cells from human amniotic fluid

Growth of cells from amniotic fluid was studied with respect to cell concentration in the inoculum, blood contamination of the fluid, fluid colour, fluid clarity, gestational age of the pregnancy, and growth factors. Dependent variables measured were colony formation, colony size, and colony morphology after 7, 11, and 14 days of culture. The following conclusions were established from these studies: small sample volumes are the most efficient for producing colonies; cells from very bloody or dark brown fluids have a slower rate of growth; growth of cells from cloudy (noncontaminated) fluids is better than growth of cells from clear fluids; the proportion of colonies that are epithelioid varies with gestational age; the stimulating effect of 100 ng/ml fibroblast growth factor on cells from amniotic fluid was confirmed.     

中国南方红壤丘陵区湖南水环境时空变化研究

以中国南方红壤丘陵区的典型区域-湖南省为例,利用1990～2000年湘、资、沅、澧四水和洞庭湖区重要断面的水质数据,采用综合污染指数方法和污染分担率方法,研究了湖南省水环境质量时空变化特征,并选取1990～2005年经济和废水排放数据,分析了经济因子与废水排放之间的相互关系,建立湖南省废水排放的库兹涅茨曲线模型。研究结果表明,从时间上看,湖南省的总体水环境污染有加重的趋势;从空间上看,水环境质量是从湖南省的西部向东部恶化。在流域和地区对比中,湘江和位于该流域的株洲市最为严重,总氮和汞是湖南省最主要的污染因子;通过环境库兹涅茨曲线模型模拟表明,湖南水环境与经济发展的关系位于环境库兹涅茨曲线上升段。本研究结果对于改善整个湖南省水环境污染状况,以便采取正确的防治策略具有一定的实践意义。     

关于显色时间对磷工作曲线影响的分析

本文利用钼锑抗分光光度法测定水中磷的监测方法,通过简要的理论、实验分析,得出采用该方法的最佳显色时间为15分钟至30分钟等经验性结论。     

联合国环境规划署（UNEP）的角色演进

环境问题是全球性问题,应对环境问题的需要催生了联合国环境规划署。其是联合国系统内最早成立的专门处理环境问题的机构,且为在全球层面上处理环境问题作出了重要贡献。自1972年成立以来,以里约会议为分界点,联合国环境规划署的发展可分为两个阶段,其在这两个阶段的发展状况有所不同。UNEP成立以来为世界环境保护事业做了很多努力,取得了可喜的成绩,但是世界环境恶化的趋势并没有得到遏制,国际环境管理体制存在着诸多的问题,UNEP面临着巨大的挑战和新的机遇。     

预腐蚀典型铆接结构疲劳寿命特性研究

通过设计LY12-CZ材料的典型铆接结构试验件与模拟现役飞机的地面停放环境,完成加速试验环境谱下的预腐蚀试验与不同时间预腐蚀后试验件的等幅疲劳试验,最终获得预腐蚀典型铆接结构疲劳寿命特性与疲劳寿命的影响系数C（t）曲线。     

鞍山市城郊污灌区农地污染状况分析与评价

土壤是人类赖以生存的自然资源,它能把大量有机物最终分解为二氧化碳和水,以及各种土壤基肥的其他组成部分,但当施入的废弃物超过土壤的自净力时,就会破坏土壤的正常机能,使之失去自然生态平衡,从而严重影响农作物的产量和品质。文章主要就鞍山市城郊污灌区的农地重金属与农药污染状况作出分析与评价,并利用趋势面分析的方法得出污染的源地,以期为鞍山市污灌区的环境整治工作提供借鉴。