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排序方式: 共有207条查询结果,搜索用时 15 毫秒
71.
对东海外陆架中部表层沉积物34个样品,南部两个岩心75个样品的沉积物特征和重矿物特征进行了分析,计算了其中有用重矿物砂的品位。东海外陆架晚更新世残留沉积中有用的重矿物砂来源于中国大陆,其含量与细砂含量、重矿物总量、沉积物的粒度和分选性呈正相关关系。重矿物砂赋存在海退层位中,形成于滨岸带,并经过后期海侵过程的改造和进一步富集,主要分布在水深100~200 m范围内。外陆架中部有用重矿物砂高品位异常区面积达1.2×10.4 km锆石和石榴石品位达到Ⅰ级异常。南部岩心中异常品位的有用重矿物砂的厚度1.5~2 m,锆石品位达到工业边界品位,研究区钛铁矿普遍出现Ⅱ级和Ⅱ级以上的异常品位。东海外陆架区浅海砂矿成矿条件较好,具有较大的资源潜力,值得进一步调查研究。 相似文献
72.
Proteins of the DYRK(dual-specificity tyrosine-phosphorylation-regulated kinase) family are characterized by the presence of a conserved kinase domain and N-terminal DH box.DYRK2 is involved in regulating key developmental and cellular processes,such as neurogenesis,cell proliferation,cytokinesis,and cellular differentiation.Herein,we report that the ortholog of DYRK2 found in zebrafish shares about 70% identity with that of human,mouse,and chick.RT-PCR showed that DYRK2 is expressed maternally and zygotica... 相似文献
73.
The South China Sea (SCS) is significantly influenced by El Nio and the Southern Oscillation (ENSO) through ENSO-driven atmospheric and oceanic changes.We analyzed measurements made from 1960 to 2004 to investigate the interannual variability of the latent and sensible heat fluxes over the SCS.Both the interannual variations of latent and sensible heat fluxes are closely related to ENSO events.The low-pass mean heat flux anomalies vary in a coherent manner with the low-pass mean Southern Oscillation Index ... 相似文献
74.
CHEN JiTao HAN ZuoZhen ZHANG XiaoLei FAN AiPing & YANG RenChao College of Geological Science Engineering Sh ong University of Science Technology Qingdao China School of Earth Environmental Sciences Seoul National University Seoul - South Korea 《中国科学:地球科学(英文版)》2010,(2)
Ribbon rocks are characterized by an alternation of millimeter-to centimeter-thick limestone and argillaceous deposits (marlstone or shale).The sedimentary processes and diagenetic characteristics of ribbon rocks might be critical to the formation of limestone conglomerates.According to detailed field measurement and laboratory analyses (thin section observation and XRD analysis),four types of ribbon rocks are classified,i.e.,limestone and marlstone couplet (L-M),limestone and shale couplet (L-S),thin-bedde... 相似文献
75.
采用1965—2007年山东省地面测站的逐日降水量和同期NCEP日平均再分析资料,运用统计学方法,探讨了季内降水分型、季节内振荡及旱涝突变的气候特征。结果表明,主要分为全省一致Ⅰ、东西反相Ⅱ、南北反相Ⅲ三种类型。他们的季内旱涝急转显示了典型的气候意义,Ⅰ型在6月下旬旱涝急转、8月中旬后期和9月初涝旱急转,与山东“夏季”雨季开始、结束时间的关键期是一致的。分型不仅限于山东,而是有着更广的旱涝区域。当Ⅰ型正相位时500 hPa高度场对应亚欧-北太平洋中高纬度为正距平,Ⅱ型表现出西北太平洋西岸的PJ波列,Ⅲ型对应着从西太沿岸-美洲西岸的类PNA型遥相关。 相似文献
76.
77.
Compositions of Upper Mantle Fluids Beneath Eastern China: Implications for Mantle Evolution 总被引:2,自引:0,他引:2
ZHANG Mingjie WANG Xianbin LIU Gang ZHANG Tongwei BO WenruiInstitute of Geological Science Lanzhou University Lanzhou Gansu Key Lab of Gas-Geochemistry Lanzhou Institute of Geology CAS Lanzhou Gansu First Institute of Oceanography State Oceanic Administration Qingdao Shandong 《《地质学报》英文版》2004,78(1):125-130
The composition of gases trapped in olivine, orthopyroxene and clinopyroxene in Iherzolite xenoliths collected from different locations in eastern China has been measured by the vacuum stepped-heating mass spectrometry. These xenoliths are hosted in alkali basalts and considered as residues of partial melting of the upper mantle, and may contain evidence of mantle evolution. The results show that various kinds of fluid inclusions in Iherzolite xenoliths have been released at distinct times, which could be related to different stages of mantle evolution. In general, primitive fluids of the upper mantle (PFUM) beneath eastern China are dominated by H2, CO2 and CO, and are characterized by high contents of H2 and reduced gases. The compositions of PFUM are highly variable and related to tectonic settings. CO, CO2 and H2 are the main components of the PFUM beneath cratons; the PFUM in the mantle enriched in potassic metasomatism in the northern part of northeastern China has a high content of H2, while CO2 a 相似文献
78.
Quantitative Analysis of Groundwater Flow near a Partially Penetrating River under Riverside Pumping
WANG Bingchen ZHENG Xilai QIAN Hui LIN Guoqing XU Qian Comprehensive Institute of Geotechnical Survey Beijing Institute of Environmental Science Engineering China Ocean University Qingdao Shandong Department of Water Resources Chang''an University Xi''an Shaanxi 《《地质学报》英文版》2004,78(3):820-824
According to practical geological and hydrogeological conditions of riverside water-supply well fields in northwestern China, an ideal hydrogeological model has been generalized and a three-dimensional mathematical model has been set up. A finite difference method was applied to simulating groundwater flow near a partially penetrating river under riverside pumping, and to analyzing the effects of river width, partial penetration and permeability of riverbed sediments on groundwater recharges. Results show that riverside pumping may cause groundwater to flow beneath the partially penetrating river, and that river width, penetration and riverbed permeability obviously influence flows from the partially penetrating river and constant-head boundaries. However, the pumping output is mainly from the partially penetrating river. 相似文献
79.
ZHENG Xilai WANG Bingchen LI Yuying XIA Wenxiang Institute of Environmental Science Engineering Ocean University of Chin Qingdao Shandong Comprehensive Institute of Geotechnical Survey Beijing 《《地质学报》英文版》2004,78(3)
On the basis of site investigation and sample collection of petroleum contaminants in the soil-water-crop system in the Shenyang-Fushun sewage irrigation area, the physical-chemical-biological compositions of the unsaturated zone is analyzed systematically in this paper. At the same time, the degradation kinetics of residual and aqueous oils is determined through biodegradation tests. The studies show that dominant microorganisms have been formed in the soils after long-term sewage irrigation. The microorganisms mainly include bacteria, and a few of fungus and actinomycetes. After a 110-days' biodegradation test, the degradation rate of residual oil is 9.74%-10.63%, while the degradation rate of aqueous oil reaches 62.43%. This indicates that the degradation rate of low-carbon aqueous oil 相似文献
80.