近50年鄱阳湖流域实际蒸发量的变化及影响因素

流域的实际蒸发是水文循环和水量平衡的重要组成部分,分析鄱阳湖流域的实际蒸发对该流域水资源研究有重要意义。选取应用范围较广的互补相关蒸发模型,估算鄱阳湖流域9个气象站1955～2001年实际蒸发量,采用统计学方法分析该时段流域实际蒸发的年内变化特征。结果表明:流域蒸发年内呈单峰型变化,峰值出现在7月份;季节变化上,夏季最大,冬季最小,春季高于秋季。选用Db3小波函数分析9站蒸发量变化趋势,结果表明:该流域蒸发量在计算时段内呈现逐步下降趋势,1998年左右转折,之后下降速度变缓。与流域同期降水量、潜在蒸发量以及太阳辐射、温度、水汽压差和风速等气象要素的对比分析认为,实际蒸发量下降的主要是由太阳净辐射和风速的下降引起的.     

First report on development of quantitative interspecies structure-carcinogenicity relationship models and exploring discriminatory features for rodent carcinogenicity of diverse organic chemicals using OECD guidelines

Different regulatory agencies in food and drug administration and environmental protection worldwide are employing quantitative structure-activity relationship (QSAR) models to fill the data gaps related with properties of chemicals affecting the environment and human health. Carcinogenicity is a toxicity endpoint of major concern in recent times. Interspecies toxicity correlations may provide a tool for estimating sensitivity towards toxic chemical exposure with known levels of uncertainty for a diversity of wildlife species. In this background, we have developed quantitative interspecies structure-carcinogenicity correlation models for rat and mouse [rodent species according to the Organization for Economic Cooperation and Development (OECD) guidelines] based on the carcinogenic potential of 166 organic chemicals with wide diversity of molecular structures, spanning a large number of chemical classes and biological mechanisms. All the developed models have been assessed according to the OECD principles for the validation of QSAR models. Consensus predictions for carcinogenicity of the individual compounds are presented here for any one species when the data for the other species are available. Informative illustrations of the contributing structural fragments of chemicals which are responsible for specific carcinogenicity endpoints are identified by the developed models. The models have also been used to predict mouse carcinogenicities of 247 organic chemicals (for which rat carcinogenicities are present) and rat carcinogenicities of 150 chemicals (for which mouse carcinogenicities are present). Discriminatory features for rat and mouse carcinogenicity values have also been explored.     

基于集对分析的江苏省土地利用协调性研究

从协调性的研究现状来看,现有研究的基础性工作缺失,且受到“均衡发展”思想束缚、不能很好地描述不确定性问题,而基于集对分析方法的协调性研究可以很好地解决以上问题.以江苏省土地利用系统为研究对象,首先运用典型相关分析对子系统之间的相关性进行验证;其次,引入集对分析思想,对土地利用的效益协调性和消耗协调性进行了评价.结果显示:土地利用变化子系统同土地利用各效益子系统之间表现出较为显著的相关性;土地利用的效益协调度大多处于较为协调状态.其内部结构表明,虽然当前政府在促进经济社会发展的同时更加注重对生态环境的保护,但并没有从根本上解决经济发展和生态环境恶化之间的矛盾;消耗协调度变动幅度相对较小,土地利用变化同土地利用效益之间基本呈现“均衡”发展态势.政府逐渐认识到用地规模的过度扩张所带来的各种负面影响,追逐用地效益的提升成为发展的主线.与以往研究结论不同的是,效益协调度和消耗协调度均没有表现出显著的持续增长态势.     

南京市土地利用协调发展度分区评价研究

本文基于土地利用协调度评价模型,构建了南京市土地利用协调发展度评价指标体系,以南京市各区县为评价单元,综合分析了南京市各区县土地利用协调发展状况与影响因素。对于属于环境提前型的区县,可在环境容量允许的条件下重点加强经济建设,适当通过加大土地资源的开发力度而提高土地利用程度,提升土地利用的社会经济效益水平;属于经济提前型的区县则需更加关注生态环境质量的改善,加强生态环境建设。     

Toxicity of 58 substituted anilines and phenols to algae Pseudokirchneriella subcapitata and bacteria Vibrio fischeri: comparison with published data and QSARs

A congeneric set of 58 substituted anilines and phenols was tested using the 72-h algal growth inhibition assay with Pseudokirchneriella subcapitata and 15-min Vibrio fischeri luminescence inhibition assay. The set contained molecules substituted with one, two or three groups chosen from -chloro, -methyl or -ethyl. For 48 compounds there was no REACH-compatible algal toxicity data available before. The experimentally obtained EC50 values (mg L⁻¹) for algae ranged from 1.43 (3,4,5-trichloroaniline) to 197 (phenol) and for V. fischeri from 0.37 (2,3,5-trichlorophenol) to 491 (aniline). Only five of the tested 58 chemicals showed inhibitory effect to algae at concentrations >100 mg L⁻¹, i.e. could be classified as “not harmful”, 32 chemicals as “harmful” (10-100 mg L⁻¹) and 21 as “toxic” (1-10 mg L⁻¹). The occupied para-position tended to increase toxicity whereas most of the ortho-substituted congeners were the least toxic. As a rule, the higher the number of substituents the higher the hydrophobicity and toxicity. However, in case of both assays, the compounds of similar hydrophobicity showed up to 30-fold different toxicities. There were also assay/organism dependent tendencies: phenols were more toxic than anilines in the V. fischeri assay but not in the algal test. The comparison of the experimental toxicity data to the data available from the literature as well as to QSAR predictions showed that toxicity of phenols to algae can be modeled based on hydrophobicity, whereas the toxicity of anilines to algae as well as toxicity of both anilines and phenols to V. fischeri depended on other characteristics in addition to logK_ow.     

聚苯乙烯磺酰肼基二硫代甲酸盐树脂功能化程度的分光光度测定

用改进的方法合成了对甲苯磺酰肼基二硫代甲酸钾。以它作模型化合物,在酸性条件下加热解,放出二硫化碳,被二乙胺及醋酸铜的混合液吸收,生成黄色荒氨酸铜,在４３０ｎｍ波长比色,从而建立了定量测定磺酰肼基二硫代甲酸基团的方法。     

关联度分析法和模糊综合评判法在泥石流沟谷危险度划分中的应用——以北京市北部山区怀柔、密云两县为例

在选取沟谷纵比降、山坡坡度、沟谷沉积物厚度、山坡堆积物厚度、流域相对高差、每平方米节理数、最大粒径、沟宽等８个因子为泥石流沟谷危险度划分的主要因子的基础上,运用关联度分析法和模糊综合评判法对北京市北部山区重点泥石流沟进行了危险度划分。结果表明,两种方法所划分的危险度与实际情况基本符合。其中,模糊综合评判法较关联度分析法更加理想一些。     

云南热区几种人工林土壤变化研究

在云南热区营造山桂花、西南桦、马尖相思、高阿丁枫等4种人工林,只要经营得当,对林地土壤理化性质并不造成重大影响,不会引起地力迅速衰退。4种人工林土壤变化的大致趋势是:1993~1995年肥力大多略呈下降趋势,1995~1997年有所上升。