期刊文献+
共找到33,393篇文章
< 1 2 250 >
每页显示 20 50 100
Three-dimensional Modeling of Ore-forming Elements and Mineralization Prognosis for the Yechangping Mo Deposit,Henan Province,China
1
作者 DING Gaoming JI Genyuan +5 位作者 YAN Guolong XU Yongzhong WANG Kunming XIAO Chun WANG Quanle GUO Dongbao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第3期736-752,共17页
Three-dimensional geochemical modeling of ore-forming elements is crucial for predicting deep mineralization.This approach provides key information for the quantitative prediction of deep mineral localization,three-di... Three-dimensional geochemical modeling of ore-forming elements is crucial for predicting deep mineralization.This approach provides key information for the quantitative prediction of deep mineral localization,three-dimensional fine interpolation,analysis of spatial distribution patterns,and extraction of quantitative mineral-seeking markers.The Yechangping molybdenum(Mo)deposit is a significant and extensive porphyry-skarn deposit in the East Qinling-Dabie Mo polymetallic metallogenic belt at the southern margin of the North China Block.Abundant borehole data on oreforming elements underpin deep geochemical predictions.The methodology includes the following steps:(1)Threedimensional geological modeling of the deposit was established.(2)Correlation,cluster,and factor analyses post delineation of mineralization stages and determination of mineral generation sequence to identify(Cu,Pb,Zn,Ag)and(Mo,W,mfe)assemblages.(3)A three-dimensional geochemical block model was constructed for Mo,W,mfe,Cu,Zn,Pb,and Ag using the ordinary kriging method,and the variational function was developed.(4)Spatial distribution and enrichment characteristics analysis of ore-forming elements are performed to extract geological information,employing the variogram and w(Cu+Pb+Zn+Ag)/w(Mo+W)as predictive indicators.(5)Identifying the western,northwestern,and southwestern areas of the mine with limited mineralization potential,contrasted by the northeastern and southeastern areas favorable for mineral exploration. 展开更多
关键词 3D geochemical model ore-forming elements GEOSTATISTICS deep mineralization prediction Yechangping Mo deposit
下载PDF
Solving the Olbers’s Paradox, Explaining the “Red-Shift”, and Challenging the Relativities by “Sun Matters Theory” and “Sun Model of Universe”, an Evolution of the Einstein’s Static Universe Model
2
作者 Wanpeng Sun 《Natural Science》 2024年第2期7-18,共12页
Olbers’s paradox, known as the dark night paradox, is an argument in astrophysics that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. Big-Bang theory was used ... Olbers’s paradox, known as the dark night paradox, is an argument in astrophysics that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. Big-Bang theory was used to partially explain this paradox, while introducing new problems. Hereby, we propose a better theory, named Sun Matters Theory, to explain this paradox. Moreover, this unique theory supports and extended the Einstein’s static universe model proposed by Albert Einstein in 1917. Further, we proposed our new universe model, “Sun Model of Universe”. Based on the new model and novel theory, we generated innovative field equation by upgrading Einstein’s Field Equation through adding back the cosmological constant, introducing a new variable and modifying the gravitationally-related concepts. According to the Sun Model of Universe, the dark matter and dark energy comprise the so-called “Sun Matters”. The observed phenomenon like the red shift is explained as due to the interaction of ordinary light with Sun Matters leading to its energy and frequency decrease. In Sun Model, our big universe consists of many universes with ordinary matter at the core mixed and surrounded with the Sun Matters. In those universes, the laws of physics may be completely or partially different from that of our ordinary universe with parallel civilizations. The darkness of night can be easily explained as resulting from the interaction of light with the Sun Matters leading to the sharp decrease in the light intensity. Sun Matters also scatter the light from a star, which makes it shining as observed by Hubble. Further, there is a kind of Sun Matters named “Sun Waters”, surrounding every starts. When lights pass by the sun, the Sun Waters deflect the lights to bend the light path. According to the Sun Model, it is the light bent not the space bent that was proposed in the theory of relativities. 展开更多
关键词 Olbers’s Paradox Sun matters Theory Sun Model of Universe Einstein’s Universe Dark Mass
下载PDF
Organic matter occurrence and pore-forming mechanisms in lacustrine shales in China 被引量:1
3
作者 Li-Chun Kuang Lian-Hua Hou +6 位作者 Song-Tao Wu Jing-Wei Cui Hua Tian Li-Jun Zhang Zhong-Ying Zhao Xia Luo Xiao-Hua Jiang 《Petroleum Science》 SCIE CAS CSCD 2022年第4期1460-1472,共13页
The evolution of pore structure in shales is affected by both the thermal evolution of organic matter(OM)and by inorganic diagenesis,resulting in a wide variety of pore structures.This paper examines the OM distributi... The evolution of pore structure in shales is affected by both the thermal evolution of organic matter(OM)and by inorganic diagenesis,resulting in a wide variety of pore structures.This paper examines the OM distribution in lacustrine shales and its influence on pore structure,and describes the process of porosity development.The principal findings are:(i)Three distribution patterns of OM in lacustrine shales are distinguished;laminated continuous distribution,clumped distribution,and stellate scattered distribution.The differences in total organic carbon(TOC)content,free hydrocarbon content(S_(1)),and OM porosity among these distribution patterns are discussed.(ii)Porosity is negatively correlated with TOC and plagioclase content and positively correlated with quartz,dolomite,and clay mineral content.(iii)Pore evolution in lacustrine shales is characterized by a sequence of decreasing-increasing-decreasing porosity,followed by continuously increasing porosity until a relatively stable condition is reached.(iv)A new model for evaluating porosity in lacustrine shales is proposed.Using this model,the organic and inorganic porosity of shales in the Permian Lucaogou Formation are calculated to be 2.5%-5%and 1%-6.3%,respectively,which correlate closely with measured data.These findings may provide a scientific basis and technical support for the sweet spotting in lacustrine shales in China. 展开更多
关键词 Shale oil Unconventional oil and gas Organic matter Pore evolution Log interpretation model
下载PDF
Persistent alterations in gray matter in COVID-19 patients experiencing sleep disturbances:a 3-month longitudinal study
4
作者 Kaixuan Zhou Gaoxiong Duan +19 位作者 Ying Liu Bei Peng Xiaoyan Zhou Lixia Qin Lingyan Liang Yichen Wei Qingping Zhang Xiaocheng Li Haixia Qin Yinqi Lai Yian Lu Yan Zhang Jiazhu Huang Jinli Huang Yinfei Ouyang Bolin Bin Mingming Zhao Jun Liu Jianrong Yang Demao Deng 《Neural Regeneration Research》 SCIE CAS 2025年第10期3013-3024,共12页
Sleep disturbances are among the most prevalent neuropsychiatric symptoms in individuals who have recovered from severe acute respiratory syndrome coronavirus 2 infections.Previous studies have demonstrated abnormal b... Sleep disturbances are among the most prevalent neuropsychiatric symptoms in individuals who have recovered from severe acute respiratory syndrome coronavirus 2 infections.Previous studies have demonstrated abnormal brain structures in patients with sleep disturbances who have recovered from coronavirus disease 2019(COVID-19).However,neuroimaging studies on sleep disturbances caused by COVID-19 are scarce,and existing studies have primarily focused on the long-term effects of the virus,with minimal acute phase data.As a result,little is known about the pathophysiology of sleep disturbances in the acute phase of COVID-19.To address this issue,we designed a longitudinal study to investigate whether alterations in brain structure occur during the acute phase of infection,and verified the results using 3-month follow-up data.A total of 26 COVID-19 patients with sleep disturbances(aged 51.5±13.57 years,8 women and 18 men),27 COVID-19 patients without sleep disturbances(aged 47.33±15.98 years,9 women and 18 men),and 31 age-and gender-matched healthy controls(aged 49.19±17.51 years,9 women and 22 men)were included in this study.Eleven COVID-19 patients with sleep disturbances were included in a longitudinal analysis.We found that COVID-19 patients with sleep disturbances exhibited brain structural changes in almost all brain lobes.The cortical thicknesses of the left pars opercularis and left precuneus were significantly negatively correlated with Pittsburgh Sleep Quality Index scores.Additionally,we observed changes in the volume of the hippocampus and its subfield regions in COVID-19 patients compared with the healthy controls.The 3-month follow-up data revealed indices of altered cerebral structure(cortical thickness,cortical grey matter volume,and cortical surface area)in the frontal-parietal cortex compared with the baseline in COVID-19 patients with sleep disturbances.Our findings indicate that the sleep disturbances patients had altered morphology in the cortical and hippocampal structures during the acute phase of infection and persistent changes in cortical regions at 3 months post-infection.These data improve our understanding of the pathophysiology of sleep disturbances caused by COVID-19. 展开更多
关键词 brain structure cortical gray matter volume cortical surface area cortical thickness HIPPOCAMPUS magnetic resonance imaging Pittsburgh Sleep Quality Index severe acute respiratory syndrome coronavirus 2 infections sleep disturbances sub-cortical volume
下载PDF
私营企业“家族治理”锁定现象的经济解释——基于“Law Matters”假说的解释与政策启示 被引量:3
5
作者 董志强 蒲勇健 《江苏社会科学》 CSSCI 北大核心 2004年第4期83-87,共5页
近年来学者们一直试图从社会学、文化学角度解释我国私营企业锁定于家族治理的现象。这些解释缺乏全球比较视角以及实证支撑而受到质疑。近来公司治理的最新成就强调了法律对治理方式选择的决定性影响,构成了“LawMatters(法律重要)”... 近年来学者们一直试图从社会学、文化学角度解释我国私营企业锁定于家族治理的现象。这些解释缺乏全球比较视角以及实证支撑而受到质疑。近来公司治理的最新成就强调了法律对治理方式选择的决定性影响,构成了“LawMatters(法律重要)”假说。这一假说可以很好地解释私营企业家族锁定的成因:一方面缺乏投资者保护导致家族担心经理攫取而不愿放弃控制权;另一方面缺乏投资者保护导致金融市场贫瘠,进而使控制家族难以分散其股权。两个原因都迫使企业锁定在家族治理,而实证表明后一个原因可能更重要。这些结论可以很好地用于解释中国私营企业家族治理锁定现象,并得到相应的政策启示。 展开更多
关键词 私营企业 金融市场 家族治理 中国 LAW matters假说
下载PDF
新加坡Chemistry Matters教材酸、碱、盐知识分析及启示 被引量:1
6
作者 刘克文 王昊 《化学教育》 CAS 北大核心 2015年第23期2-6,共5页
基于命题和页幅2个方面对新加坡Chemistry Matters教材中酸、碱、盐知识进行了定量分析,研究了其在内容选取、结构编排、呈现方式等方面的特点,并给出了一些启示。
关键词 新加坡化学教材 CHEMISTRY matters 酸、碱、盐教材设计
下载PDF
聚焦园长行为胜任力的提升:新加坡Principal Matters园长培训项目的探索与启示 被引量:6
7
作者 洪秀敏 朱文婷 《外国中小学教育》 CSSCI 北大核心 2018年第12期50-57,共8页
园长培训是提升和促进园长专业发展的重要手段。新加坡Principal Matters园长培训项目,致力于提升园长的行为胜任力。该项目培训主体多元互补,打破培训领域单一壁垒;培训内容聚焦园长行为胜任力,并研制行为胜任力模型;培训形式创新且与... 园长培训是提升和促进园长专业发展的重要手段。新加坡Principal Matters园长培训项目,致力于提升园长的行为胜任力。该项目培训主体多元互补,打破培训领域单一壁垒;培训内容聚焦园长行为胜任力,并研制行为胜任力模型;培训形式创新且与行为胜任力提升相匹配;注重行为胜任力提升效果的实时监测与后期验证,在实践中取得了良好成效。可为我国园长培训项目的改善及高素质专业化的园长队伍建设提供启示与参考。 展开更多
关键词 园长培训 Principalmatters 新加坡 行为胜任力
下载PDF
新加坡生物学主流教材习题的特征探析及启示--以《Biology Matters》为例
8
作者 刘杨 宋思涵 辛坤坤 《中学生物学》 2023年第4期82-84,共3页
以新加坡Biology Matters生物学教材习题为研究对象,分析得出其具有“绘图作答,提高学生形象思维能力”,“情境多样,注重学生对现象的解释”,“联系生活,强调知识解决实际问题”,“探讨伦理,引导学生承担社会责任”“分层设问,培养学生... 以新加坡Biology Matters生物学教材习题为研究对象,分析得出其具有“绘图作答,提高学生形象思维能力”,“情境多样,注重学生对现象的解释”,“联系生活,强调知识解决实际问题”,“探讨伦理,引导学生承担社会责任”“分层设问,培养学生思维的逻辑性”等特征,希望对我国生物学测评试题的命制具有一定的启示意义。 展开更多
关键词 新加坡Biology matters 生物学 习题特征
下载PDF
Source profiles of particulate organic matters emitted from cereal straw burnings 被引量:89
9
作者 ZHANG Yuan-xun SHAO Min +5 位作者 ZHANG Yuan-hang ZENG Li-min HE Ling-yan ZHU Bin WEI Yong-jie ZHU Xian-lei 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第2期167-175,共9页
Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain ... Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters (PMzs) from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon (EC) and organic carbon (OC) was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum (GC-MS). Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. 13-Sitostrol also made up relatively a large fraction of PMz5 compared with the other sterols (0.18%-0.63% of the total fine particle mass). Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index (CPI) of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches. 展开更多
关键词 biomass burning cereal straw particulate organic matter source profile
下载PDF
Geochemical Characteristics and Sources of Ore-forming Fluids of the Mayuan Pb-Zn Deposit,Nanzheng,Shaanxi,China 被引量:5
10
作者 LIU Shuwen LI Ronxi +3 位作者 CHI Guoxiang ZENG Rong LIU Lingfang SHI Shun 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第3期783-793,共11页
The Mayuan stratabound Pb-Zn deposit in Nanzheng,Shaanxi Province,is located in the northern margin of the Yangtze Plate,in the southern margin of the Beiba Arch.The orebodies are stratiform and hosted in breciated do... The Mayuan stratabound Pb-Zn deposit in Nanzheng,Shaanxi Province,is located in the northern margin of the Yangtze Plate,in the southern margin of the Beiba Arch.The orebodies are stratiform and hosted in breciated dolostone of the Sinian Dengying Formation.The ore minerals are primarily sphalerite and galena,and the gangue minerals comprise of dolomite,quartz,barite,calcite and solid bitumen.Fluid inclusions from ore-stage quartz and calcite have homogenization tempreatures from 98 to 337℃ and salinities from 7.7 wt%to 22.2 wt%(NaCl equiv.).The vapor phase of the inclusions is mainly composed of CH_4 with minor CO_2 and H_2S.The δD_(fluid) values of fluid inclusions in quartz and calcite display a range from-68‰ to-113‰(SMOW),and the δ^(18)O_(fluid)values calculated from δ^(18)O_(quartz) and δ^(18)O_(calcite) values range from 4.5‰ to 16.7‰(SMOW).These data suggest that the ore-forming fluids may have been derived from evaporitic sea water that had reacted with organic matter.The δ^(13)C_(CH4) values of CH_4 in fluid inclusions range from-37.2‰ to-21.0‰(PDB),suggesting that the CH_4 in the ore-forming fluids was mainly derived from organic matter.This,together with the abundance of solid bitumen in the ores,suggest that organic matter played an important role in mineralization,and that the thermochemical sulfate reduction(TSR) was the main mechanism of sulfide precipitation.The Mayuan Pb-Zn deposit is a carbonate-hosted epigenetic deposit that may be classified as a Mississippi Valley type(MVT) deposit. 展开更多
关键词 fluid inclusion ore-forming fluids organic matter Mayuan Pb-Zn deposit SHAANXI
下载PDF
In, Sn, Pb and Zn Contents and Their Relationships in Ore-forming Fluids from Some In-rich and In-poor Deposits in China 被引量:16
11
作者 ZHANG Qian ZHU Xiaoqing +1 位作者 HE Yuliang ZHU Zhaohui 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2007年第3期450-462,共13页
All the indium-rich deposits with indium contents in ores more than 100×10^-6 seems to be of cassiterite-sulfide deposits or Sn-bearing Pb-Zn deposits, e.g., in the Dachang Sn deposit in Guangxi, the Dulong Sn-Zn... All the indium-rich deposits with indium contents in ores more than 100×10^-6 seems to be of cassiterite-sulfide deposits or Sn-bearing Pb-Zn deposits, e.g., in the Dachang Sn deposit in Guangxi, the Dulong Sn-Zn deposit in Yunnan, and the Meng'entaolegai Ag-Pb-Zn deposit in Inner Mongolia, the indium contents in ores range from 98×10^-6 to 236×10^-6 and show a good positive correlation with contents of zinc and tin, and their correlation coefficients are 0.8781 and 0.7430, respectively. The indium contents from such Sn-poor deposits as the Fozichong Pb-Zn deposit in Guangxi and the Huanren Pb-Zn deposit in Liaoning are generally lower than 10×10^-6, i.e., whether tin is present or not in a deposit implies the enrichment extent of indium in ores. Whether the In enrichment itself in the ore -forming fluids or the ore-forming conditions has actually caused the enrichment/depletion of indium in the deposits? After studying the fluid inclusions in quartz crystallized at the main stage of mineralization of several In-rich and In-poor deposits in China, this paper analyzed the contents and studied the variation trend of In, Sn, Pb and Zn in the ore-forming fluids. The results show that the contents of lead and zinc in the ore-forming fluids of In-rich and -poor deposits are at the same level, and the lead contents range from 22×10^-6 to 81×10^-6 and zinc from 164×10^-6 to 309×10^-6, while the contents of indium and tin in the ore-forming fluids of In-rich deposits are far higher than those of Inpoor deposits, with a difference of 1-2 orders of magnitude. Indium and tin contents in ore-forming fluid of In-rich deposits are 1.9×10^-6-4.1×10^-6 and 7×10^-6-55×10^-6, and there is a very good positive correlation between the two elements, with a correlation coefficient of 0.9552. Indium and tin contents in ore-forming fluid of In-poor deposits are 0.03×10^-6-0.09×10^-6 and 0.4×10^-6-2.0×10^-6, respectively, and there is no apparent correlation between them. This indicates, on one hand, that In-rich oreforming fluids are the material basis for the formation of In-rich deposits, and, on the other hand, tin probably played a very important role in the transport and enrichment of indium. 展开更多
关键词 In-rich deposit In-poor deposit ore-forming fluid fluid inclusion ore-forming elements
下载PDF
Rare Earth Elements Geochemistry of Laowan Gold Deposit in Henan Province: Trace to Source of Ore-Forming Materials 被引量:12
12
作者 谢巧勤 徐晓春 +2 位作者 李晓萱 陈天虎 陆三明 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第1期115-120,共6页
The compositions of REE in quartz and pyrite from the main stage of the Laowan gold deposit in Henan Province and that in quartz from Laowan granite were determined by inductively coupled plasma-mass-spectrometry (IC... The compositions of REE in quartz and pyrite from the main stage of the Laowan gold deposit in Henan Province and that in quartz from Laowan granite were determined by inductively coupled plasma-mass-spectrometry (ICP-MS) to trace the source of ore-forming materials. Meanwhile, the REE compositions of the deposit ore, granite and metamorphic wall rock were also considered for comparative studies in detail. The range of ∑REE of quartz and pyrite from the deposit ores is 4.18 × 10^-6- 30.91 × 10^-6, the average of ∑REE is 13.39 × 10^-6, and the average of ∑REE of quartz in the Laowan granite is 6.68 × 10^-6. There is no distinct difference of REE parameters between the deposit ore quartz and granite quartz. The quartz in gold deposit has the same REE particular parameters as quartzes from Laowan granite, such as δEu, δCe, (La/Yb)N and (La/Sm)N, partition degree of LREE to HREE, especially, the chondrite-normalized REE patterns, but no similarity to those from metamorphic wall rock, which shows that ore-forming hydrothermal fluid is mainly the fluid coming from the Laowan granite magma, rather than metamorphic fluid. Meanwhile, comparison studies on REE features between minerals from the deposit ores and related geological bodies in the deposit show that REE characteristics of minerals can serve as an indicator of ore-forming fluid properties and sources, while the REE characteristics of the bulk samples (such as deposit ores, granites and wall rocks) can not trace the source of the ore-forming materials exactly. 展开更多
关键词 Laowan gold deposit REE geochemistry source of the ore-forming material ore-forming fluid rare earths
下载PDF
Binding of pyrene to dissolved organic matters: fractionation and characterization 被引量:5
13
作者 DAIJing-yu ZHOUJiang-min QINShu-ping 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2004年第6期928-933,共6页
Based on a modified Leenheer DOM fractionation scheme, fractionation of DOM from the paddy soil was conducted by using XAD-8 resin into hydrophobic bases(HOB), hydrophobic acids(HOA), acid-insoluble matter(AIM), hydro... Based on a modified Leenheer DOM fractionation scheme, fractionation of DOM from the paddy soil was conducted by using XAD-8 resin into hydrophobic bases(HOB), hydrophobic acids(HOA), acid-insoluble matter(AIM), hydrophobic neutrals(HON) and hydrophilic matter(HIM). In total carbon content of DOM, 35.32% were the HIM and only 0.73% the HOB. However, HOA and AIM altogether occupied 53.45%, while the HON fraction represented 10%. The sorption experiments were conducted to determine the sorption capacity of pyrene on unfractionated DOM and its fractions. Elemental analysis, 1H-NMR and FTIR spectra were carried out on unfractionated DOM and its fractions to examine the relationship between the structure of DOM and partition coefficients(K oc). The results showed that HON had a greater affinity for binding pyrene than other fractions. While HON was characterized by large long-chain alkylate (aliphatic structure). AIM exhibited relative higher K oc values than HOA and HIM, due to much aromatic structure in AIM, while the high content of carboxylic groups of HOA and HIM depressed their binding capacity. This study demonstrated HON is a key subcomponents of DOM in binding of pyrene, in other words, aliphalic structure in DOM play an important role in binding of pyrene. 展开更多
关键词 dissolved organic matter(DOM) PYRENE FRACTIONATION SORPTION
下载PDF
REE Geochemistry of Sulfides from the Huize Zn-Pb Ore Field, Yunnan Province: Implication for the Sources of Ore-forming Metals 被引量:15
14
作者 LI Wenbo HUANG Zhilong QI Liang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2007年第3期442-449,共8页
REE abundances in sulfides from the Huize Zn-Pb ore field were determined with the ICPMS after preconcentration. The REE abundances in 26 sulfide samples (including pyrite, galena and sphalerite) are very low, with ... REE abundances in sulfides from the Huize Zn-Pb ore field were determined with the ICPMS after preconcentration. The REE abundances in 26 sulfide samples (including pyrite, galena and sphalerite) are very low, with the ~REE ranging from 1.6×10^-9 to 166.8×10^-9. Their LREE/HREE ratios range from 7.6 to 98, showing LREE enrichment relatively. The JEu values are below 1, indicating that they were deposited from an Eu-depleted and reducing fluid-system. Similar to the ore-hosting carbonate strata, calcite separates from carbonate veinlets filling in the fractures or faults crosscutting the carbonate strata also show clear Eu-depletion. This indicates that the carbonate veinlets and their parent fluid was possibly sourced from the strata and inherited the REE geochemical features of the strata. Therefore, REE-geochemical characteristics of both the sulfides and calcites, which were deposited from an ore-forming hydrothermal system, are similar to those of carbonate strata, and strongly suggest that the ore metals were mainly sourced from carbonate strata. 展开更多
关键词 Huize Zn-Pb ore field REE geochemistry SULFIDE fluid ore-forming metal
下载PDF
Numerical Modelling of Ore-forming Dynamics of Fractal Dispersive Fluid Systems 被引量:8
15
作者 邓军 方云 +3 位作者 杨立强 杨军臣 孙忠实 王建平 丁式江 王庆飞 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2001年第2期220-332,共13页
Based on an analysis of the fractal structures and mass transport mechanism of typical shear-fluid-ore formation system, the fractal dispersion theory of the fluid system was used in the dynamic study of the ore forma... Based on an analysis of the fractal structures and mass transport mechanism of typical shear-fluid-ore formation system, the fractal dispersion theory of the fluid system was used in the dynamic study of the ore formation system. The model of point-source diffusive illuviation of the shear-fluid-ore formation system was constructed, and the numerical simulation of dynamics of the ore formation system was finished. The result shows that: (1) The metallogenic system have nested fractal structure. Different fractal dimension values in different systems show unbalance and inhomogeneity of ore-forming processes in the geohistory. It is an important parameter to symbolize the process of remobilization and accumulation of ore-forming materials. Also it can indicate the dynamics of the metallogenic system quantitatively to some extent. (2) In essence, the fractal dispersive ore-forming dynamics is a combination of multi-processes dominated by fluid dynamics and supplemented by molecule dispersion in fluids and fluid-rock interaction. It changes components and physico-chemical properties of primary rocks and fluids, favouring deposition and mineralization of ore-forming materials. (3) Gold ore-forming processes in different types of shear zones are quite different. (1) In a metallogenic system with inhomogeneous volumetric change and inhomogeneous shear, mineralization occurs in structural barriers in the centre of a shear zone and in geochemical barriers in the shear zone near its boundaries. But there is little possibility of mineralization out of the shear zone. (2) As to a metallogenic system with inhomogeneous volumetric change and simple shear, mineralization may occur only in structural barriers near the centre of the shear zone. (3) In a metallogenic system with homogeneous volumetric change and inhomogeneous shear, mineralization may occur in geochemical barriers both within and out of the shear zone. 展开更多
关键词 fluid system fractal dispersion point-source illuviation model ore-forming dynamics numerical simulation
下载PDF
Distribution and its mechanism of suspended particulate matters in the southern Huanghai Sea and the East China Sea in summer 被引量:3
16
作者 QIAO Lulu LIU Yong +3 位作者 CHEN Jiaojie MA Yanyan LI Guangxue SONG Jun 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2011年第5期94-100,共7页
Water temperature,turbidity,chlorophyll-a and suspended sediment concentration (SSC) were investigated at 61 stations of eight sections in the southern Huanghai Sea (HS) and the East China Sea (ECS) during the s... Water temperature,turbidity,chlorophyll-a and suspended sediment concentration (SSC) were investigated at 61 stations of eight sections in the southern Huanghai Sea (HS) and the East China Sea (ECS) during the summer (28 June to 15 July) of 2006.The horizontal distribution of suspended parti culate matter (SPM) displayed a high concentration inshore and a low value offshore.The maximum value can reach 10.4 mg/dm 3,which can be found at the Changjiang River mouth.For the same site,the SSC was generally higher at the bottom than on the surface.In the vertical direction,distribution characteristics of turbidity can be divided into two types:in the southern HS high values at the bottom while low values on the surface,and in the ECS high values inshore with low values offshore.The thermocline in the HS and the Taiwan Warm Current in the ECS could be important factors preventing the SPM from diffusing upward and seaward.Even the typhoon Ewiniar was not able to work on the major sediment transport under the thermocline during the observation. 展开更多
关键词 TURBIDITY suspended particulate matter SUMMER THERMOCLINE warm current
下载PDF
Particulate Matters Pollution Characteristic and the Correlation between PM (PM<sub>2.5</sub>, PM<sub>10</sub>) and Meteorological Factors during the Summer in Shijiazhuang 被引量:7
17
作者 Han Li Bin Guo +2 位作者 Mengfei Han Miao Tian Jin Zhang 《Journal of Environmental Protection》 2015年第5期457-463,共7页
In recent years, the haze occurs frequently and air pollution is getting worse in Beijing-Tianjin-Hebei Region, China. The particulate matter pollution characteristic researches are playing a sig-nificant role especia... In recent years, the haze occurs frequently and air pollution is getting worse in Beijing-Tianjin-Hebei Region, China. The particulate matter pollution characteristic researches are playing a sig-nificant role especially in the districts where have higher concentration PM and air pollution. In this study, we collected daily particulate matter (PM10, PM2.5) mass concentration data from 7 air pollution monitoring stations in Shijiazhuang City, Hebei, China over a 3-month period from June to August to investigate particulate matter pollution characteristic and the relationship with me-teorological conditions. Statistical results show that PM10 is the major pollutant in Shijiazhuang City;the average daily concentrations of PM2.5 and PM10 are 94.45 μg/m3 and 219.15 μg/m3, respectively. The daily average of PM10 and PM2.5 level over the period exceeded the first grade of the daily average limit of the ambient air quality standards (GB3095-2012). And there is a significantly positive correlation between atmospheric pressure and particulate matter pollution, but there is a significantly negative correlation between atmospheric temperature and PM concentrations. Precipitation has a clear role mainly in the coarse particles;however, there has little effect on fine particulate matter. Relative humidity and wind speed have a poor correlation with atmospheric pollutant concentrations (not remarkably high). 展开更多
关键词 PARTICULATE matter Air POLLUTION METEOROLOGICAL Factors Shijiazhuang
下载PDF
REE Geochemistry of Fluorite from the Maoniuping REE Deposit,Sichuan Province,China:Implications for the Source of Ore-forming Fluids 被引量:3
18
作者 HUANG Zhilong XU Cheng +6 位作者 Andrew McCAIG LIU Congqiang WU Jing XU Deru LI Wenbo GUAN Tao XIAO Huayun 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2007年第4期622-636,共15页
Fluorite is one of the main gangue minerals in the Maoniuping REE deposit, Sichuan Province, China. Fluorite with different colors occurs not only within various orebodies, but also in wallrocks of the orefield. Based... Fluorite is one of the main gangue minerals in the Maoniuping REE deposit, Sichuan Province, China. Fluorite with different colors occurs not only within various orebodies, but also in wallrocks of the orefield. Based on REE geochemistry, fluorite in the orefleld can be classified as the LREE-rich, LREE-flat and LREE-depleted types. The three types of fluorite formed at different stages from the same hydrothermal fluid source, with the LREE-rich fluorite forming at the relatively early stage, the LREE-flat fluorite in the middle, and the LREE-depleted fluorite at the latest stage. Various lines of evidence demonstrate that the variation of the REE contents of fluorite shows no relation to the color. The mineralization of the Maouiuping REE deposit is associated spatially and temporally with carbonatite-syenite magmatism and the ore-forming fluids are mainly derived from carbonatite and syenite melts. 展开更多
关键词 FLUORITE REE geochemistry ore-forming fluid Maoniuping REE deposit
下载PDF
Ore-forming Fluid Systems and Mineralization in the Eastern Jiangnan Uplift in the Border Area of Anhui and Jiangxi Provinces, China 被引量:3
19
作者 ZHOUTaofa YUANFeng +4 位作者 HOUMingjin FAnYu DUJianguo ZHUGuang YUEShucang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第2期380-386,共7页
Obvious differences in mineralization characteristics exist between the southern and northern parts of the eastern part of the Jiangnan Uplift in northern Jiangxi Province and southern Anhui Province. The regional met... Obvious differences in mineralization characteristics exist between the southern and northern parts of the eastern part of the Jiangnan Uplift in northern Jiangxi Province and southern Anhui Province. The regional metallogeny is discussed, and the ore-forming fluid systems are classified in this article. It is proposed that the fluid ore-forming activities in the Jiangnan Uplift both in northern Jiangxi and southern Anhui have close relationships with the crust-mantle interaction and magmatic-tectonic activities. The types and scales of the mineralization on the both sides of the eastern Jiangnan Uplift were determined by fluid ore-forming systems and geological backgrounds. 展开更多
关键词 ore-forming fluid systems MINERALIZATION Jiangnan Uplift ANHUI northern Jiangxi
下载PDF
Total N,total P and organic matters content in floodplain soils of Xianghai Nature Reserve 被引量:2
20
作者 DENG Wei, ZHAI Jin-liang, HE Yan (Changchun Institute of Geography, CAS, Changchun 130021, China) 《Journal of Geographical Sciences》 SCIE CSCD 2002年第1期58-64,共7页
Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matter... Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matters were analyzed. The results showed that contents of total N, total P and organic matters were generally decreasing with the increase of distance from sample locations to the river channel, and contents of the three items were generally higher in the upper soil layer than that in the lower soil layer. The content variations displayed how flooding functions influenced nutrient matter content variations in floodplain soils since the flood inundation frequencies of the sample locations varied. The correlation analysis displayed that there were remarkable relativities between total N, total P and organic matters within definite spatial distance from the Huolin River channel. 展开更多
关键词 floodplain wetland total N total P organic matter correlation analysis
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部