城市扩展与热岛空间分布变化关系研究——以上海为例

随着城市建设区域和格局的迅速改变,城市热岛分布也发生了巨大变化.为了了解城市热岛分布与城市建设的关系,为城市建设同时缓解改善热岛效应奠定基础,文章采用遥感动态监测和GIS多要素空间分析技术,对上海城市90年代以来的城市扩展以及热岛分布变化状况和演变规律进行监测分析,得出城市建设区域的扩大将会导致城市热岛范围和面积的增大,城市扩展与热岛扩展趋势具有空间一致性.同时,通过对上海城市不同温度情况下地面不同介质的比例、面积进行因子权重分析,得出温度越高,其建筑、交通、工业区的比例越大;反之温度越低,农田、耕地等介质的比例越高;表明不同地物对温度分布、强度的影响明显.研究还表明:城市扩展虽会导致热岛范围加大,但如注重环境和绿化建设,则在一定程度上可缓解热岛效应和缩小热岛范围.     

珠江三角洲城市墙壁植物资源及其应用

墙壁植物对城市绿化和改良生态环境具有重要价值.调查表明珠江三角洲城市墙壁植物共有94种,隶属于42科,76属,主要集中在菊科、禾本科、桑科、茜草科、凤尾蕨科、大戟科,部分植物为彩叶植物,其中分布数量较多有29种,以桑科和菊科最为突出,具有较强的适应能力.然后对墙壁植物的耐旱性、观赏性、应用进行了分析和评价,结果表明耐旱强的种类有29种,观赏性较高的种类有56种;最后对墙壁植物在墙面和围墙绿化提出了一些建议.     

诺氟沙星的氯化反应及其遗传毒性的变化

分别以诺氟沙星初始浓度为10μg·1-1和25 mg·1-1进行氯化消毒实验,用HPLC和SCS/umu遗传毒性测试方法,分别测定不同氯化消毒反应时间后残留诺氟沙星的浓度和遗传毒性,反应速度常数分别为0.0243 min-1和0.0226 min-1;在高浓度反应组,反应45 min后反应液的遗传毒性效应有明显的提高,其EC50为131 nmo·1-1,低于反应前的EC50(181 nmol·1-1),表明在反应过程中生成了遗传毒性高于母体的中间产物.     

中美新化学物质管理制度的比较

简要叙述了中美两国新化学物质管理的基本情况,分别从管理原则、管理范围、管理具体要求、申报种类、评审程序、监督管理等方面重点论述了中美新化学物质管理制度的特点。通过借鉴美国新化学物质管理的优点及经验,提出了强化和完善中国新化学物质管理制度的对策。     

氢氧化镁对水中As（Ⅲ）的吸附作用

以氢氧化镁为吸附材料,通过单因素实验分别考察了氢氧化镁投加量、pH、温度、吸附时间对吸附效果的影响。研究了氢氧化镁对As（Ⅲ）的吸附热力学和动力学特性,并对作用机理进行了探讨。结果表明：在砷初始浓度为0.5～100 mg/L之间,温度为25℃,pH为3,氢氧化镁投加量为0.5～4 g,吸附时间为1 h的条件下,氢氧化镁...     

Perfluorinated compounds in the Pearl River and Yangtze River of China

A total of 14 perfluorinated compounds (PFCs) were quantified in river water samples collected from tributaries of the Pearl River (Guangzhou Province, south China) and the Yangtze River (central China). Among the PFCs analyzed, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the two compounds with the highest concentrations. PFOS concentrations ranged from 0.90 to 99 ng/l and <0.01–14 ng/l in samples from the Pearl River and Yangtze River, respectively; whereas those for PFOA ranged from 0.85 to 13 ng/l and 2.0–260 ng/l. Lower concentrations were measured for perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctanesulfoamide (PFOSA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorononaoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA). Concentrations of several perfluorocarboxylic acids, including perfluorododecanoic acid (PFDoDA), perfluorotetradecanoic acid (PFTeDA), perfluorohexadecanoic acid (PFHxDA) and perfluorooctadecanoic acid (PFOcDA) were lower than the limits of quantification in all the samples analyzed. The highest concentrations of most PFCs were observed in water samples from the Yangtze River near Shanghai, the major industrial and financial centre in China. In addition, sampling locations in the lower reaches of the Yangtze River with a reduced flow rate might serve as a final sink for contaminants from the upstream river runoffs. Generally, PFOS was the dominant PFC found in samples from the Pearl River, while PFOA was the predominant PFC in water from the Yangtze River. Specifically, a considerable amount of PFBS (22.9–26.1% of total PFC analyzed) was measured in water collected near Nanjing, which indicates the presence of potential sources of PFBS in this part of China. Completely different PFC composition profiles were observed for samples from the Pearl River and the Yangtze River. This indicates the presence of dissimilar sources in these two regions.