68 research outputs found

    Chlorofullerenes featuring triple sequentially fused pentagons

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    通讯作者地址: Tan,YZ(通讯作者),Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Coll Chem & Chem Engn, Dept Chem, Xiamen 361005, Peoples R China 电子邮件地址: [email protected], [email protected] triple sequentially fused pentagons (TSFP) motif is one of the basic subunits that could be used for constructing fullerenes, but it violates the isolated pentagon rule (IPR) and has not been found in carbon cages to date. The properties of TSFP-incorporating fullerenes are thus poorly explored both theoretically and experimentally. Reported herein are four chlorinated derivatives of three different fullerene cages, all with the TSFP motif. X-ray crystallographic analyses indicate that the molecular strain inherent to the pentagon adjacency of a TSFP is significantly relieved upon exohedral chlorination, leaving one of the four pentagon fusion sites unsaturated and rendering the present derivatives chiral. This unique reactivity, in stark contrast to that of previously reported non-IPR fullerenes containing double fused pentagons or triple directly fused pentagons, can be rationalized by density functional theory calculations, and are expected to stimulate further studies of these new members of the fullerene family, both theoretically and experimentally.NNSF of China 20525103,20531050,20721001,20423002 20673088 973 Program 2007CB81530

    HYDROLOGICAL OBSERVATION IN AN EVERGREEN BROAD LEAVED FOREST IN THE WUYI MOUNTAINS

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    [中文文摘]对武夷山甜槠林成熟林水文学效应的研究结果表明:观测期间,年大气降水量2678.78mm,林内雨量2182.04mm,林冠截留量为496.74mm;林内雨中,穿透雨量2082.08mm,树干茎流99.96mm;到达甜槠林地作用面的林内雨量中,被地表枯枝落叶层截留的雨量为159.84mm,地表径流量11.6mm,地下渗流量109.32mm,其余林内雨量形成土壤含水量增量并由地表物理蒸发、根系吸收以及植物蒸腾所消耗;甜槠林地o~200cm土层水分初渗率78.6mm·min-1,稳渗率15.5mm·min-1,达到稳渗历时45min,地表枯枝落叶最大持水量5.2mm,土壤蓄水量154.0mm。与国内其它地区不同类型的森林相比较,武夷山甜槠林具有较强的水文学效能。[英文文摘]Hydrological observations were made in a 76 year old Castanopsis eyrei forest of the Wuyi Mountains.The results are as follows:(1)In the study period during 1993~1994,annual gross precipitation,net precipitation (throughfall was 208204mm and stemflow was 9996mm)and interception loss were 267878mm,218204mm and 49674mm respectively.Interception rate was 1845%.(2)Net precipitation,the part of gross precipitation appearing on the forest floor,was redistributed through different routes.The part absorbed by litter layer was an annual amount of 15984mm,and accounting for 733%.The parts as surface runoff and below ground drainage were annual amounts of 116mm and 10932mm respectively,and accounting for0.53% and 5.01%,respectively.The rest was kept in soil and then lost to the atmosphere by means of ground physical evaporation or plant transpiration as absorbed by the roots.Its amount was 190128mm,and accounting for 87.13%.(3) The initial infiltration rate and stable infiltration rate for the soil layer of 0~20cm were 786mm·min-1 and 155mm·min-1 respectively.The time needed to arrive at the stable state was 45min.Water storage capacity of soil was 15041t·hm-2.The maximum water holding capacity of litter layer was 52mm.福建省自然科学基金,武夷山自然保护区管理局资

    浮选药剂对软体动物的毒性研究

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    <正> 浮选药剂随着选矿废水排入水体对水生态系统的影响如何?这是人们普遍关注的一个问题。水体中水生生物种类繁多,国内外学者较多的使用鱼类和浮游生物作为毒理学研究的试验生物。软体动物是底栖动物中的重要类群之一,并具有一定的经济价值。Gupta等和Stuart等用酚及其衍生物对尖头椎实螺(Lymnaea acum-inata)和用五氯苯酚对肥鳃螺(Gillia altilis)分别进行过毒性研究,均取得了较好的效果。本研究选用椭圆萝卜螺和大脐圆扁螺作为试验

    水环境中松油的化学生态学特征

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    <正> 松油(Pine oil)是我国有色金属矿浮选工艺中常用的一种起泡剂,它通过选矿排放的废水输入水环境,并产生一定的危害。但是,一个很重要的问题——松油在水环境中的归宿几乎没有人进行过研究,本文正是这方面的一个初探。 本文报道:1.选矿用松油主要化学组分的定性定量研究结果;2.水环境中松油降解产物的初步剖析;3.降解产物与松油化学组分之间的关系

    新型浮选剂MPA对鱼类毒性效应的研究

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    MPA是一种新型浮选剂,主要由29种醇类化合物组成。测得它的96h的LC_(50)值:草鱼胚胎为100—200mg/L;草鱼苗为75.86mg/L;草鱼种为122.77mg/L。引起草鱼胚胎弯体畸形的EC_(50)值为48.98mg/L。弯体不严重的鱼苗在清水中饲养,能恢复成正常的鱼苗。对鱼苗生长没有影响的浓度是6.65mg/L。浓度为100mg/L的MPA在水环境中一周能去除一半,20天后未检出,在该浓度内放入的草鱼种,对其生长没有明显的影响

    有机有毒污染物在土壤及底泥系统中的吸附/解析行为研究进展

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    本文对有机有毒污染物在土壤及底泥系统中的吸附/解析行为的研究进展进行了较系统的阐述,其中包括基本概念及原理,动力学模型,与吸附/解析行为相关的作用,研究新方法及有机有毒污染物的定量结构-活性关系
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