翡翠贻贝对多氯联苯吸收不同途径的比较研究   总被引：5，自引：0，他引：5  

方展强 《热带海洋学报》2003,22(5):63-70

定量分析和比较翡翠贻贝Perna viridis对多氯联苯(PCBs)吸收的4种不同途径。结果表明，翡翠贻贝通过食物途径富集PCBs比从海水吸收的途径具更高效率；而通过底泥或悬浮颗粒积累PCBs的途径较为次要。翡翠贻贝对5—7个氯原子数的PCBs异构体富集率高，分别占PCBs总量的53．25％-77．41％。结果还表明，贻贝经沉积物途径和经滤食悬浮颗粒途径比经水途径和食物途径对含2—4个氯原子数和8—10个氯原子数的PCBs异构体富集率较高。  相似文献   

Occurrence, thermal evolution and primary migration processes derived from studies of organic matter in the Lucaogou source rock at the southern margin of the Junggar Basin, NW China     

JIAO YangQuan  WU LiQun  HE MouChun  ROGER Mason  WANG MinFang  XU ZhiCheng 《中国科学D辑(英文版)》2007,50(Z2):114-123

The Lucaogou Formation carbonate-rich oil shale source rock is exposed at the southern margin of the Junggar Basin, Xinjiang, NW China. We have sampled it in detail and conducted microstructural, mineralogical and geochemical studies, including thin section petrography, UV fluorescence petrography, X-ray diffraction, vitrinite reflectance, bitumen reflectance, fluid inclusion analysis and Raman spectroscopy. Organic matter is disseminated through the carbonate-bearing siltstone source rocks and concentrated in numerous bedding parallel stylolites and in two sets of carbonate veins, one along bedding parallel fractures and the other cross-cutting stylolites and bedding. The research about maturity of organic matter finds vitrinite reflectance values increase from the dispersed kerogen (0.64%) to the stylolites (the one of oriented vitrinite is 0.72% and the one of migrated bitumen is 2.38%); Homogenization temperatures of fluid inclusions in veins containing hydrocarbon fluid inclusions show an increase from 178.5℃ in the bedding parallel veins to 222℃ in the cross-cutting veins, confirmed by Raman spectroscopy. These results support a model of progressive heating accompanied by fluid loss during later stages of thermal maturation of source rock and the onset of primary migration. Obviously, the occurrence of organic matter is the trace of hydrocarbon primary migration, and the bedding lamination surfaces and cross-cutting fissures are the principal pathways of hydrocarbon-bearing fluids migration. Bedding lamination surfaces evolved into stylolites along the earliest primary migration pathways, followed by bedding parallel and cross-cutting fissures.  相似文献   

Plant functional types and climate along a precipitation gradient in temperate grasslands, north-east China and south-east Mongolia   总被引：1，自引：0，他引：1  

Jian Ni 《Journal of Arid Environments》2003,53(4):501-516

Using data from three field surveys along a precipitation gradient of temperate grasslands in north-east China (the Northeast China Transect, NECT) and south-east Mongolia, the spatial distribution of six plant functional types (PFTs): C₃ species, C₄ species, grasses, shrubs, forbs and succulents and their relationships with climate were analysed. The spatial distribution of different PFTs varies in different regions and in different grassland types of the study area. The species richness in each PFT also has different relationships with climate (significantly or not). Generally, the number of C₃ species, C₄ species, grasses and forbs have positive relationships with precipitation and aridity. Shrubs have negative relationship with precipitation and aridity. Succulents were found to have no relationship with precipitation and aridity. Shrubs, grasses and forbs have stronger relationships with precipitation than C₃ and C₄ species. The relationships between C₃ species, forbs and aridity are more significant than with precipitation. On a regional basis, the combined effect of precipitation and temperature, the aridity, is more significantly correlated with the distribution of C₃ species and forbs, which are more dominant in the study area, than with C₄ species, grasses and succulents.  相似文献   

视力下降与颅内病变的CT分析     

张广平  何平 《CT理论与应用研究》1998,7(3):15-17

本文对１０５例主要因视力下降来我院进行头颅ＣＴ扫描患者,他们的ＣＴ片进行全面分析。作者挑选出与视力有关的颅内病３１例,以此实例来进行分析视力下降与颅内病变发生的部位的关系,同时说明影响视路的程度差别。  相似文献   

滨洲断裂白垩纪末活动性定量评价及其对油气运聚的意义   总被引：1，自引：0，他引：1       下载免费PDF全文

杨勉  孙卫华 《地质科学》2009,44(2):715-721

本文利用构造应力场数值模拟结果,通过断裂活动性的判别准则对松辽瓮地滨洲断裂的活动性进行了定量评价,指出明水组沉积末期（油气人量运移期）该断裂的活动性受盆地构造格局的严格控制：盆地范围外的西北段断裂未发牛活动,盆地范围内的东南段断裂呈活动状态.滨洲断裂呈活动状态的东南段为齐家-古龙凹陷油气向西北方向富拉尔基油田运移提供了通道条件.文中采用的方法所得的评价结果与其它油气运移研究结果相-致,证明了本方法的可行性.  相似文献   

油气优势运移通道的类型及其物理模拟实验研究   总被引：25，自引：0，他引：25  

姜振学庞雄奇  曾溅辉王洪玉 罗群 《地学前缘》2005,12(4):507-516

地质分析和物理模拟实验证实地质条件下油气总是沿着浮力最大和阻力最小的的方向和通道运移,形成油气优势运移通道有5种基本模式:级差优势、分隔优势、流向优势、流压优势和断面优势。物理模拟实验结果表明油气运移实际通道只占输导层的1%~10%,但却运输了油气的绝大部分;输导层物性的差异、盖层沉降中心的偏移、流体动力、断层倾角及断层面几何形态控制了油气运移的优势通道;实际地质条件下油气运移所形成的优势通道是上述5种模式综合作用的结果。由于优势通道是大部分油气运移的实际路径,其研究对追踪油气来源、预测有利圈闭有着十分重要的作用。  相似文献   

关中盆地近地面风场和大气输送特征分析     

胡洵  蔡旭晖  宋宇  康凌 《气候与环境研究》2020,25(6):637-648

利用2017年151个地面气象站的逐时观测数据和相关高空资料分析关中盆地近地面风场与输送特征。首先分析盆地内代表性站点的风速和风向观测事实,然后用CALMET风场诊断模式和轨迹计算模式获取当地逐小时风场和每日逐小时传输轨迹,分析风场类型。结果表明:关中盆地内日平均风速约1～3 m s?1,夏季风速高、秋冬季低;盆地中央的主导风向以沿地形走向的东北风和西南风为主,盆地四周测站的主导风向表现出顺着地形向盆地中央汇流的趋势。各站主导风向的季节变化不大。盆地内风场分为系统控制型、弱天气背景型和局地环流型3类,全年出现日数比例分别占8%、17.3%和74.7%。以山谷风日夜循环为特征的局地环流型风场最多。以西安城区为源点的大气输送轨迹显示,系统控制型风场以偏东北方向的输送为主,弱天气背景型和局地环流型风场的轨迹输送都大致以偏东北和偏西（以及偏西南）沿盆地走向以及偏东南朝向秦岭山地这三个方向为主。局地环流型的轨迹影响范围小,集中于盆地中央和南侧山地之间,表明这是一种不利于污染扩散的风场类型。  相似文献   

鄂尔多斯盆地东部上古生界石千峰组低压气藏特征   总被引：18，自引：0，他引：18  

杨华 姬红李振宏  孙六一 《地球科学》2004,29(4):413-419

鄂尔多斯盆地的气源主要来自于山西组-太原组的海陆交互相煤系地层, 上石盒子组沉积了一套巨厚的泥岩, 具有很强的封盖能力, 天然气很难穿层运移.近年来, 相继在盆地东部的石千峰组地层中发现了一系列次生气藏, 其形成机理逐步引起了勘探家的关注.根据次生气藏的特点, 结合包裹体测试计算, 认为其形成原因主要是由于下部超压地层进行超压释放, 从而在区域性盖层内部形成一系列泄压通道, 原生气藏泄漏而形成的.形成过程主要经历了下部高温高压原生气藏的形成、原生气藏泄压与次生气藏的形成、次生气藏的长时间调整3个阶段.   相似文献   

安徽某矿区强水敏性地层钻进泥浆的试验研究     

滕子军  金永军 《煤田地质与勘探》2002,30(6):63-64

针对富含钙蒙脱石的水敏性地层会遇水膨胀,导致钻孔缩径等问题,借鉴石油钻井中采用的正电胶MMH泥浆体系,在进行室内试验优选配方的基础上,进行了野外试验,取得了良好的效果。   相似文献   

High-precision measurements of the inter-annual evolution for Urumqi Glacier No.1 in eastern Tien Shan,China     

ChunHai Xu  ZhongQin Li  JianXin Mu  PuYu Wang  FeiTeng Wang 《寒旱区科学》2021,13(6):474-487

High-precision measuring of glacier evolution remains a challenge as the available global and regional remote sensing techniques cannot satisfactorily capture the local-scale processes of most small- and medium-sized mountain glaciers. In this study, we use a high-precision local remote sensing technique, long-range terrestrial laser scanning (TLS), to measure the evolution of Urumqi Glacier No.1 at an annual scale. We found that the dense point clouds derived from the TLS survey can be used to reconstruct glacier surface terrain, with certain details, such as depressions, debris-covered areas, and supra-glacial drainages can be distinguished. The glacier experienced pronounced thickness thinning and continuous retreat over the last four mass-balance years (2015-2019). The mean surface slope of Urumqi Glacier No.1 gradually steepened, which may increase the removal of glacier mass. The glacier was deeply incised by two very prominent primary supra-glacial rivers, and those rivers presented a widening trend. Extensive networks of supra-glacial channels had a significant impact on accelerated glacier mass loss. High-precision measuring is of vital importance to understanding the annual evolution of this type of glacier.  相似文献