石墨炉原子吸收光谱法测定水中的痕量钼

介绍了用石墨炉（无火焰）原子吸收光谱法直接测定饮用水、地表水及废水中痕量钼的原理、过程，讨论了实验条件的优化、线性范围的选择，并对检出限、精密度和准确度做出评估。对钼标准物质（编号GBW199041）进行测定，测定结果与标准值相吻合。该方法测定的线性范围为0．0047mg／L-0．1000mg／L，检测限为0．0001mg／L，相对标准差为0．8％～1．6％，回收率为101%～107%，具有线性范围宽，简单，快速，准确等特点，在饮用水、地表水及废水中痕量钼的检测中具有很好的适用性。     

二恶英的来源、危害及污染控制

二恶英不仅来源于苯酚类杀虫剂，消毒剂，而且来源于含氯化学工业品，通过呼吸系统和食物链富集进入人体，造成人体许多复杂疾病并引起环境激素问题，应从源头治理，加强二恶英的检测和食品安全管理，提高人们的自我防范意识。     

气候舒适度的体感分级：季节锚点法与中国案例

气候舒适度对人居环境和人类活动具有深远影响,相关的评价模型/指数在建筑设计、城市规划、人体健康和旅游发展等领域有着广泛应用。体感分级标准作为气候舒适度评价模型不可或缺的关键环节,对模型效度有着重要的裁量权,也是实践应用中最终的度量衡工具。目前体感分级标准研究和应用中异地套用和局地实测的传统做法,在制定国家尺度普适性标准时遇到较大瓶颈。本文试图提出包含“定级—定名—定点—定宽”等基本环节的“季节锚点法”这一新的体感分级思路,并基于中国1981-2010年间814个基本（基准）气象站点的日值气象数据,以温湿指数和风效指数为例开展了实证研究。研究给出了“暑—热—暖—温—凉—冷—寒”这一针对中国区域的7级体感划分标准,并具体给出了温湿指数和风效指数在各体感等级上的阈值区间,进而在此基础计算评价了中国气候舒适期和不舒适期的时间长短、空间格局及其历时变化,得到一些有益发现。未来的研究可以进一步就细分人群、测试模型和区域差异等方面的体感分级标准开展更多深入探索。     

珠江三角洲城市人居环境测评与分析

基于人居环境系统理论,运用层次分析法构建了一个包含四个一级子系统、九个二级子系统和三十六个基层指标的珠三角城市人居环境评价指标体系.选取1997年、2000年和2002年三个时间断面对珠三角城市人居环境进行测算.结果表明,珠三角城市人居环境系统工业化中期阶段特征明显,人居环境建设开始进入软环境主导时代,但发展的协调性和稳定性明显较差.同时人居环境的改善还面临着区域产业整合带来的严峻挑战.     

Landscape ecological characteristics in temporal changes of riverside open space in urbanized area

１ＩｎｔｒｏｄｕｃｔｉｏｎＲｅｃｅｎｔｌｙｉｎＪａｐａｎ，ｔｈｅｒｉｖｅｒｓｐａｃｅｉｎｕｒｂａｎａｒｅａｓｉｓｃｈａｎｇｉｎｇｉｎｔｏｒｉｖｅｒｐａｒｋｓ，ｒｉｖｅｒｏｐｅｎｓｐａｃｅａｎｄｎａｔｕｒｅｏｒｉｅｎｔｅｄｂａｎｋ．Ｃｏｎｓｅｑｕｅｎ...     

Human Settlements on the Northern Shores of Lake Aral and Water Level Changes

The shore of Lake Aral in Kazakhstan is a perfect area for studying the human adaptation strategy to past climate changes. New archaeological material, gathered along the northern shores during the expedition of the INTAS project CLIMAN, is briefly presented. Changes in settlement activity during the Atlantic and Subboreal are related to lake level changes of the Aral Sea. A previ-ously proposed lake level maximum needs to be revised. In particular the lake level stand at 72/73 m, with an assumed age of 5000 BP is definitely refused. Based on the presented data the maximum lake level most probably never reached beyond 57/58 mean average sea level (masl). Furthermore the regression during the 15^th–16^th centuries has been underestimated. It may have been lower than the present day level. Thus the present desiccation of the Aral Sea is historically not unique, as a similar regression, probably induced by man as well, has occurred at least once during history. A readjustment of the water level is, therefore, possible at any time.     

Second-trimester maternal serum screening using alpha-fetoprotein,human chorionic gonadotrophin,and unconjugated oestriol: Experience of a regional programme

Over a 2-year period from January 1991 to December 1992, second-trimester maternal serum screening for Down's syndrome using alpha-fetoprotein (aFP), human chorionic gonadotrophin (hCG), and unconjugated oestriol (uE₃) was made available to five health districts in East Anglia, with a total population of 1·2 million. Amniocentesis was offered when the risk of Down's syndrome at term was 1:200 or greater. 25359 singleton pregnancies were screened, representing an uptake of 77 per cent. The recall rate for the 24 per cent of women who had not had a dating scan prior to the test was 9·4 per cent compared with 3·9 per cent for those who had been scanned (P<0·0005). Seventy-five per cent (36/48) of Down's syndrome pregnancies were detected for a false-positive rate of 4·0 per cent. Twenty-five out of 36 of detected Down's syndrome pregnancies were dated by scan prior to sampling, and in the 11 remaining cases, the dates were confirmed by scan after a high-risk result was obtained. The exclusion of uE₃ from the screening protocol would have reduced the detection rate to 52 per cent (25/48) for the same false-positive rate. Eighty-five per cent of women identified at high risk accepted the offer of an amniocentesis. Other fetal abnormalities detected were trisomy 18 (3), trisomy 13 (2), 45,X (6), 69,XXX (5), other chromosome abnormalities (9), open neural tube defects (26), hydrocephalus (7), abdominal wall defects (4), and steroid sulphatase deficiency (6).     

关于优化国有企业资本结构的思考

企业资本结构的合理与否,直接关系到生产经营活动的顺利进行,关系到企业的盈利状况,关 系到企业的生存和发展。调整企业资本结构是国企改革中必须注意的问题,也是财务学界重要的理论问 题。本文提出了如何优化国有企业资本结构的若干思考和相应措施。     

地下水中汞的形成及其与人群健康的关系

地下水中汞元素的形成，主要是含汞矿物岩土溶解作用的结果，但其含量一般很低。汞与人体关系密切，结肠癌、肺癌死亡率与土壤中汞含量呈正相关，胃癌死亡率则与汞元素含量呈负相关。地下水汞元素含量小于１μｇ／Ｌ时，不会对人体健康产生危害。     

青浦区城市化中人居环境的协调发展研究

青浦区人居环境的可持续发展体系是一个由人口、社会、资源、环境与经济5个子系统构成的开放巨系统。文章通过提出综合衡量系统“协调性”和“发展水平”的“协调发展度”模型，研究青浦区在城市化中人居环境复合系统内5个子系统之间协调发展度情况。并运用回归模型，探讨协调发展度与城市化发展水平之间的内在联系，提出城市化进程必须与其人居环境的可持续发展相适应。