典型山核桃产区土壤重金属空间异质性及其风险评价

山核桃(Carya cathayensis)是我国特有的高档干果和木本油料植物,目前关于山核桃林地土壤重金属污染研究鲜有报道.本研究以典型山核桃产区临安为研究区,系统采集了188个山核桃土壤样品,采用地统计学以及Moran's I等空间分析方法研究土壤重金属的空间异质性,并对山核桃林土壤重金属潜在生态风险进行评价.结果表明,重金属Cd、Cu、Zn、Pb、Ni、Cr平均含量分别为0.37、40.76、87.61、30.10、28.33、56.57 mg·kg-1,其中Cd、Cu平均值分别是背景值的1.33和2.87倍.单因子污染指数、内梅罗污染指数及潜在生态风险评价结果显示研究区土壤重金属均有样点超过土壤背景值,且Cd、Cu、Zn、Pb、Ni有部分样点超过土壤环境质量二级标准,表明研究区土壤已具有Cd、Cu、Zn、Pb、Ni、Cr不同程度的累积特征,局部土壤已受到Cd、Cu、Zn、Pb、Ni的污染,其中Cd最为严重,达到了强生态危害程度,Cu次之,总体上重金属呈中等生态危害程度.基于半方差函数分析得出,Cd、Cu、Pb、Ni、Cr具有强烈的空间自相关,而Zn属于中等空间相关性.Moran's I指数以及克里格插值结果揭示重金属Cd、Cu、Zn、Pb、Ni、Cr均存在明显的空间分布格局和局部空间聚集现象,高值主要集中在太阳、岛石、清凉峰、河桥以及湍口几个乡镇,且以重金属Cd、Cu污染风险概率较高.土壤Cd、Cu、Zn、Ni、Cr高值分布主要与矿区开采有关,而Pb与钾肥的施用密切相关.可见,研究区重金属空间分布特征受人为活动影响明显.     

广西英罗港红树林沼泽沉积物和大型底栖动物中重金属含量的研究

１９９４年测定了广西英罗港红树林区沼泽沉积物和大型底栖动物中重金属Ｃｕ、Ｐｂ、Ｚｎ和Ｃｄ的含量。结果表明：沉积物重金属含量比潮沟的高；沉积物中的重金属含量与有机质含量存在显著正相关关系；英罗港红树林区部分沉积物己受到Ｃｄ和Ｐｂ的污染。各类动物重金属平均含量Ｚｎ和Ｃｄ以软体动物，Ｃｕ以甲壳动物，Ｐｂ以星虫类最高。在动物总体水平上，林内动物重金属含量稍高于潮沟动物。在种类和动物类别水平上则无明显差别。各潮带动物重金属含量规律混乱。少数大型底栖动物受到Ｃｄ或Ｐｂ的污染。     

南京市交通干道大气环境中挥发性有机物的研究

使用Tenax管在常温下富集采样 ,研究了南京市交通干道大气环境中苯系物的污染状况和季节变化规律 ,监测过程历时 1年。同时在中山陵设点采样 ,以作背景研究。经过GC/MS联用仪分析测定 ,共检出 140多种挥发性有机物 ,其中含量较高的是苯系物。结合获得的大气中苯系物的比值以及采样点的周围环境 ,对苯系物进行源分析 ,表明苯系物主要来源于汽车尾气的排放 ,其污染程度与气候变化有关。     

海洋环境水下采油树腐蚀与防护研究进展

根据国内外水下采油树腐蚀防护技术现状,从采油树腐蚀环境、材料选择、阴极保护及涂层防护方面系统地探究了水下采油树的腐蚀防护技术,对各种技术的优缺点进行了比较分析.材料选择方面,主要对采油树的服役环境、服役要求及材料性能等进行了探究,并对常见水下采油树的材料316L、25Cr7Ni4Mo型双相不锈钢、30CrMo钢及Inconel 625等进行了分析总结.阴极保护方面,主要探究了牺牲阳极在采油树腐蚀与防护方面的应用.涂层防护方面,主要对国内外水下采油树重防腐涂层现状、标准及种类进行了综述分析.腐蚀失效方面,对其失效原因及失效分析原则和程序进行了探究.最后,就采油树的腐蚀防护材料选择、阴极保护、涂层防护及腐蚀失效方面的发展进行了展望.     

Do males and females differ in the feeding of large and small siblings? An experiment with the bluethroat

Males and females have been reported to differ in their feeding of large and small siblings in several species of birds. According to recent hypotheses, this phenomenon may be related to a sexual conflict over avian hatching patterns. We designed an experiment to test for the existence of such a sex difference by manipulating nestling size hierarchies of the bluethroat (Luscinia s. svecica) in two directions; half the broods were “asynchronized” to yield large size-differences within broods and the other half were “synchronized” to yield small size-differences. In all broods, nestlings were categorized as being either large or small according to body mass. We recorded male and female food distribution by video early (day 4 after hatching) and late (day 8) in the nestling period. Males and females did not differ in their distribution of food among different-sized nestlings. With large size-differences, both males and females fed large nestlings nearly twice as often as small ones. In contrast, when the size-differences were small, food was more evenly distributed among nestlings. Early in the nestling period, males fed more nestlings during each feeding visit than did females. Our finding that male and female bluethroats do not differ in the feeding of large and small siblings is in contrast to most previous studies. Variation in costs and benefits to males and females from feeding different-sized nestlings, and restrictions to parental choice due to nestling interactions, may explain interspecific variation. Received: 27 June 1997 / Accepted after revision: 26 January 1998     

纳氏试剂法检测水中低浓度氨氮存在问题分析及方法改进探讨

针对采用《水质氨氮的测定纳氏试剂分光光度法》(HJ 535-2009)测定低浓度氨氮时存在的测不准问题,研究了药剂投加量、反应时间等因素对检测结果的影响,认为低浓度氨氮下的显色反应速度过慢是测定结果不准的原因,并据此提出利用强碱调节pH的方法加速反应进程.改良后的方法可以在0.2～1.2 mg/L氨氮浓度范围内呈现良好...     

基于改进模拟退火算法的社会力量救灾派遣模型

为提高社会救援力量参与救灾的效率,针对社会力量参与灾后救援的派遣问题,提出最优化派遣模型及其求解算法.根据"量力而行、就近就便"等原则,综合考虑社会力量的救援技能掌握程度和灾区的救援需求情况,将最大化救援效益作为目标函数,以抵达灾区时间和救灾经济成本作为约束条件建立模型;采用模拟退火算法对模型进行求解,根据模型改进Me...     

Does female plumage coloration signal parental quality? A male removal experiment with the bluethroat (Luscinia s. svecica)

Females in several sexually dimorphic species with conventional sex roles possess ornamental traits that resemble those found in males. The evolution of such traits, however, is still poorly understood. Bluethroats (Luscinia s. svecica) are socially monogamous, sexually dichromatic passerine birds, in which female throat patch coloration varies from near absence to near full expression of male-like coloration. A recent study, demonstrating that male bluethroats prefer colourful females, suggests that female coloration is subject to sexual selection through male choice. However, the benefits males may gain from mating with colourful females have not yet been identified. In this study we tested the hypothesis that female coloration signals parental quality (the good-parent hypothesis). During the course of the same day, we recorded female care both in the presence and the absence of the male mate. The latter was done to eliminate the confounding effect of variable male care by removing the male temporarily. Female coloration did not correlate with female feeding rates either in the presence or in the absence of the male. Female feeding rates in the absence and the presence of the male were positively, although weakly, correlated. Female coloration did not correlate with female ability to compensate for the loss of male care, or with the change in brood mass during male removal. Therefore, there is no evidence for the good-parent hypothesis to explain female plumage coloration in bluethroats. Received: 4 March 1999 / Received in revised form: 14 October 1999 / Accepted: 23 October 1999     

中国高质量发展阶段最优环境保护税率研究

中国开始实施环境保护税法的时间位于从高速增长向高质量发展过渡的时期。环境保护税法规定了大气和水污染物的税率区间,因此实际执行的税率存在优化的空间。虽然征收环境保护税是为了达成环境目标,但是该项税收同样可以服务于经济和社会目标。本文拟对环境保护税这一市场化的环境政策价格工具进行优化,从这一崭新研究视角切入,探讨协调经济与环境关系的原则,以期为实现高质量发展提供理论依据。本文的研究方法基于一个包括企业、政府和消费者的世代交替模型,各经济主体进行分散化决策。企业在生产过程中排放污染,政府向企业征收环境保护税并且治理污染,消费者的内生寿命受到污染存量和人均产出的共同影响。根据市场均衡条件,本文得到描述物质资本和污染存量动态变化的非线性差分方程,在此基础上进行解析证明和数据模拟。研究得到以下三点结论:第一,同一个环境保护税率无法同时实现经济产出最大化和社会福利最大化的目标,这意味着在高质量发展阶段政府需要抛弃以经济增长为中心的政策思路,转而以社会福利最大化为目标确定最优的环境保护税率。政府提高环境保护税率,可以实现由经济产出最大化向社会福利最大化的转变。第二,相较于最大化经济产出的税率,最大化社会福利的环境保护税率在转移路径上会造成各主要变量较小的波动,并用一定的经济产出换取更多的物质资本、更优的环境质量、更长的人均寿命、以及更高的社会福利水平,因此支持了前述政府需要以社会福利最大化为目标确定最优环境保护税率的结论。第三,最大化社会福利的环境保护税率在基准模型中的数值为1.96,但污染物的异质性会影响最优税率的数值。污染物较低的自然扩散速度、较严重的健康损害程度、较高的治理技术水平都会提高最优的环境保护税率。本文提出三点政策建议:第一,通过征收环境保护税最大化社会福利水平。第二,通过提高环境保护税率体现发展理念的转变。第三,促进医疗卫生和污染治理技术进步。