Monsoonal precipitation variation in the East Asia since A.D. 1840 ——Tree-ring evidences from China and Korea

The main characteristic of the East Asian climate is the monsoon system. Plenty of studies have demonstrated that the Asian monsoon system plays a crucial role in the global climate sys- tem [1-4]. The Asian summer monsoon can be divided into two parts, t…     

声波钻进技术的发展及其应用

声波钻进是在各种覆盖层中采集连续岩心样品的有效手段。叙述了声波钻进技术的发展情况、工作原理、设备操作、优越性和用途，并且对我国研发此项技术提出了建议。     

多孔底受控定向钻孔轨迹在倾斜平面内的设计

80年代以来,我国地矿部将“定向钻探技术”列为科技攻关项目。经过不到十年的努力,在钻孔弯曲规律性研究、定向钻孔轨迹设计、人工定向和造斜工具研制、微机在定向钻探中应用等方面都取得了显著的进步。特别是机械式连续造斜器、螺杆钻造斜钻具、各类定向仪和造斜钻头的研制和试验成功,使我国岩心钻探定向钻进技术发展到了一个新的阶段。在四川、湖南、安徽、贵州、江西、新疆、河南、陕西、青海、辽宁等省先后顺利地打了一批高质量的受控定向孔,掌握了一整套施工工艺技术,积累了宝贵的生产经验。1987-1988年期间,安徽铜陵冬瓜山矿区施工了一组多方位多分枝定向孔,表明我国     

定向钻探用撑块式连续造斜器及配套器具的研究与试验

叙述了CK-73、CK-54型撑块式连续造斜器,GZ-18型钢珠式定向仪和造斜钻头的结构特点、工作性能和试验结果.室内和野外试验表明:用上述造斜器及其配套器具进行受控定向钻探、绕障及纠斜,都取得了令人满意的结果.     

定向钻探分枝孔孔身剖面的设计问题

定向钻探是利用地层造斜规律、人工造斜措施或者自然造斜与人工造斜同时并用，使钻头按照设计轨迹延伸到预定靶点（见矿点或其它地质目标）的一项新技术。近年来，由于初级定向钻探经验的积累，偏心楔结构的改进，定向器具的革新，连续造斜器和小口径螺杆钻具的研制与试验，使定向钻探技术得到了进一步的发展。高级定向钻探（即利用人工弯曲进行定向钻探，或称受控定向钻探）在生产上将获得越来越多的应用。     

Evaluation of Estrogenic Activity and Measurement of EDCs in Wastewater Treatment Plants

1IntroductionDuringthe past several years,concern hasincreasedover the potential pollution of watershed by estrogeniccompounds,including steroidal hormones fromhumanand ani mal sources.Effluents from wastewater treat-ment plants are sources of endocrine-d…     

岩芯定向和求解岩层产状的方法

利用钻探取得的岩芯确定地下岩(矿)层或断裂面的产状,是勘探工作的重要内容之一.层面产状数据对正确认识深部地质构造,查明矿体形态和延伸情况有很大价值,同时对指导勘探工程布置和矿床开采也非常重要. 在覆盖层较厚的地区,通常用三点法求层面产状,即利用相近的三个钻孔穿过同一层面的标高计算岩(矿)层或断裂面的产状要素.三点法是以岩(矿)层或断裂面为平面做基础的,因此它不能反映钻孔之间层面产状的变化,况且还要打三个孔才能算出层面产状.当标志层不明显时,往往难以判定三孔穿过的同一层面,从而不能准确了解层     

cDNA cloning and expression of a cytochrome P450 1A (CYP1A) gene from the hermaphroditic fish Rivulus marmoratus

We previously described the genomic structure of the cytochrome P450 1A (CYP1A) gene from the hermaphroditic fish Rivulus marmoratus [Kim, I.-C., Kim, Y.J., Yoon, Y.-D, Kawamura, S., Lee, Y.-S., Lee, J.-S., 2004a. Cloning of cytochrome P450 1A (CYP1A) genes from the hermaphroditic fish Rivulus marmoratus and the Japanese medaka Oryzias latipes. Mar. Environ. Res. 58, 125–129]. To further characterize R. marmoratus CYP1A, we cloned the cDNA sequence of a CYP1A gene from this species and also expressed its recombinant protein in an E. coli system. We exposed R. marmoratus to 4-nonylphenol, and found a small induction of CYP1A mRNA in the treated animals. In this paper, we discuss the characteristics of R. marmoratus CYP1A gene as well as its potential use in a biomonitoring assay.     

Freezing of sediments inappropriate for pore water selenium analysis

The common practice of freezing sediment cores for later chemical investigation was shown to be inappropriate for samples containing selenium. Pore waters from frozen estuarine sediment cores contained up to eighty times the selenium content of those extracted from chilled but unfrozen cores. Experiments suggested that the increase in selenium concentrations resulted from rupturing the cells of selenium-accumulating bacteria present in the samples.