林丹(γ-六六六)在土壤中的吸附性与其在土壤和小麦中残留量的关系

本文利用~(14)C—林丹研究了γ-六六六在不同土壤中的吸附性及其在土壤和小麦中残留量的关系。试验表明,γ-六六六在土壤中的吸附率与土壤中的有机质含量、可萃取铝含量和酸性等均有密切关系。同时,环境温度对吸附率也有一定影响。通过~(14)C—林丹在不同土壤和小麦植株中残留量的测定,证明土壤中γ-六六六的吸附率、小麦对土壤中r-六六六的吸收率以及γ-六六六在土壤和小麦中的残留量相互之间均有明显的相关性。为此,本研究不仅摸清了某些影响土壤吸附γ-六六六和小麦吸收γ-六六六的理化因子,同时,对用土壤某些理化性质的测定值来预测栽培试验时土壤和小麦中六六六的残留水平提供了一个途径。     

characteristics of PM2.5 in rural areas of southern Jiangsu Province, China

Introduction Anumberofstudiesabroadhavedemonstratedthat atmosphericfineparticulatematter(PM2.5,dp<2.5μm)is notonlyassociatedwithatmosphericvisibilityreductionbut alsohasaclearcorrelationwiththenumberofdailydeathsandhospitalizationsasaconsequenceofpulmonarydisease(Chan,1997;Christoforous,2000;Schwartz,1996;Wilson,1997).On18July,1997,theU.S.EnvironmentalProtectionAgency(USEPA)promulgatednewandsevere standardsforfineparticulates(PM2.5)withthesizebelow2.5μm(15μg m3asannualaverage,65μg m…     

Metamorphic evolution of eclogite and associated garnet-mica schist in the high-pressure metamorphic Maksyutov complex, Ural, Russia

Metasedimentary garnet-mica schists are interlayered with metabasic garnet–omphacite schists and enclose eclogite boudins in the high-pressure metamorphic Maksyutov complex in the Southern Urals, Russia. These three rock types were investigated in one outcrop and compared chemographically and thermobarometrically. The Fe/Mg distributions between garnet rim–omphacite and garnet rim–phengite pairs indicate different equilibration temperatures for the three samples, with the lowest temperature (500°C, >1.5 GPa) for the eclogite boudin, an intermediate temperature (630°C, >1.7 GPa) for the foliated eclogite and the highest temperature (650°C, >1.7 GPa) for the garnet-mica schist. The garnets in garnet-mica schist enclose abundant chloritoid relics and the Fe/Mg distribution between chloritoid and garnet records an earlier high-temperature stage (650°C, >2.0 GPa) before the garnet rim–phengite temperatures were reached. Together with some minimum- and maximum-pressure estimates three different prograde pressure–temperature paths and a common retrograde metamorphic evolution are interpreted from the chemographic and thermobarometric data. The different early metamorphic evolutions and conditions confirm the variability of protoliths, which are also indicated by different U/Pb zircon and rutile ages.     

Quantitative structure-property relationship of aromatic sulfur-containing carboxylates

IntroductionItiswidelyrecognizedthatthephysicochemicalprofileoforganicchemicalslargelydeterminestheirdistributionbetweenenvironmentalmedia .Fortheenvironmentalbehaviorsoforganiccontaminants,watersolubility(SW)andoctanol waterpartitioncoefficient(KOW)aretremendouslyimportant.Octanol waterpartitioncoefficienthasbeenwidelyrelatedtobiochemicaland orbiologicalactivityinquantitativestructure activityrelationships(QSARs) (Leo ,1 971 ) .Watersolubilitycorrespondstothedispersiontendencyandtothereca…     

粉煤灰预处理及其对染料单体脱色效果的研究

介绍了一种粉煤灰预处理的方法-用8mol/L的H2SO4处理，可较好地改善其表面状况，并用预处理后的粉煤灰对染料单体进行脱色试验，寻找了最佳的处理方案，脱色效果较好，建立了Langmuir吸附等温模型。探讨了其脱色机理，为实际开发利用粉煤灰处理印染废水提供基础研究。     

高强度钢纵梁内板的成形性分析

重点对高强度钢纵梁内板的成形性进行了分析,并且在详细分析零件几何特点的基础上,对此模型的圆角半径进行了修改,修改后零件的成形性得到了显著提高。     

机车检修污水处理回用设施实例分析

机车清洗污水经撇油、酸碱中和、气浮、过滤、活性碳吸附等工艺流程的处理后,进行全封闭循环,再用于清洗机车,合理选择污水处理工艺流程是确保处理后的污水能否经济、合理回用的关键.     

选择性离子交换法脱除水中NH3-N

采用储量较大的黑龙江省嫩江天然斜发沸石,对其脱除NH_3-N的能力、预处理及洗脱再生方法、交换平衡、交换动力学等进行系统的研究,并对沸石床层的交换过程进行数学模型计算。     

铜、锌和锰抑制月形藻生长的毒性效应

运用评价化学品毒性藻类测试的标准实验方法，得到铜、锌和锰对月形藻生长的最小无显著差异浓度（LNOEC）分别为31.8μg/L、16.4μg/L和2.7mg/L，抑制月形藻生长的96h半效应浓度（96h-EC50)分别为199.5μg/L、38.0μg/L和12.6mg/L。实验结果表明无论从LNOEC还是从96h-EC50考虑，都证明抑制月形藻生长的毒性由大到小的顺序是锌＞铜＞锰。此结果对铜抑制藻类生长的毒性远远大于锌的毒性这一人们普遍认同的观点构成挑战。月形藻细胞壁表面可能含有较少的硫代基团但包含较多与锌有很强结合能力的官能团可能是导致月形藻对铜的敏感性弱而对锌敏感性强的主要原因。