维普中文期刊产品整合服务
252篇 您的检索式:作者名="Wenxuan"
    题名 作者 年代 出处 被引量
1Hydrothermal recrystallization of the Lower Ordovician dolomite and its significance to reservoir in northern Tarim Basin显示文摘Discovered in S15 and some other wells, the Lower Ordovician in the northern Tarim Basin consists mainly of brown gray-dark gray very fine-fine crystalline dolomite, with a minor portion of locally light gray-white medium-coarse crystalline dolomite. Silicification can be observed in the medium-coarse dolomite, and some euhedral drusy quartz can also be found in pores and fractures of the dolomite. The homogenization temperature of the fluid inclusions in the medium-coarse dolomite is between 110 and 200°C with maximum between 140 and 190°C, and the salinity is between 10.7 and 18.5 wt.% NaCl Eq. The homogenization temperature and salinity of the fluid inclusions in the medium-coarse dolomite are similar to those in the drusy quartz. Compared with the very fine-fine dolomite, the medium-coarse phase contains relatively high Fe and Mn. The average concentration of FeO and MnO in the medium-coarse dolomite is 1.917% and 0.323%, respectively. The medium-coarse dolomite has a remarkable negative Eu anomaly, consistent with the REE pattern of the intermediate-felsic igneous rocks in the Tarim Basin. The oxygen isotopic composition of the medium-coarse dolomite is relatively lighter than that of the very fine-fine dolomite. The δ18OPDB values of the medium-coarse dolomite are between -10.35‰ and -7.31‰. The δ18OSMOW values of the fluid associated with the medium-coarse dolomite can be calculated according to homogenization temperature and oxygen isotope fractionation factor between dolomite and fluid, and the calculated values are between +4‰ and +10‰, consistent with those of the hydrothermal fluid. The medium-coarse dolomite has relatively high 87Sr/86Sr ratios as well, indi- cating an origin associated with intermediate-felsic igneous rock. The homogenization temperature, element composition, REE pattern, oxygen and strontium isotopes demonstrate that the medium-coarse dolomite is the result of recrystallization of very fine-fine dolomite under hydrothermal environment. The hydrothermal dolomite recrystallization is a special event but exists extensively in the Tarim Basin. The recrystallized dolomite becomes well reservoir bed for many intercrystalline pores and dissolution pores are produced in this event, so that more attention should be paid to the altered dolomite during the petroleum exploration in the lower Paleozoic in the Tarim Basin.ZHU DongYa JIN ZhiJun HU WenXuan 2010Science China Earth Sciences2010,53,3:34
2An atomic force microscopy study of coal nanopore structure显示文摘Coal nanopore structure is an important factor in understanding the storage and migration of absorbed gas in coal. A new method for studying coal nanopore structures is proposed. This idea is based on the nano-level resolution of atomic force microscopy, which can be employed to observe the structural features of coal nanopores clearly, conduct quantitative three-dimensional measurements and obtain structural parameters. Analysis results show that coal nanopores are mainly metamorphic pores and intermolecular pores. The metamorphic pores are commonly rounded and elliptical, increasing quantitatively with the coalification degree. The forms of intermolecular pores change markedly. The average pore size of low-rank coal is bigger than high-rank coal, and the number of intermolecular pores decreases as the coal rank increases. Section analysis effectively characterizes the coal pore microstructure, bearing analysis is a vital approach to measure microporosity, and grain analysis can be employed to study the pore size distribution. Atomic force microscopy is a tool for the in-depth research of coal pore microstructure and the coal-bed methane adsorption mechanism.YAO SuPing JIAO Kun ZHANG Ke HU WenXuan DING Hai LI MiaoChun PEI WenMing 2011Chinese Science Bulletin2011,56,25:30
3Global leaf nitrogen and phosphorus stoichiometry and their scaling exponent显示文摘Leaf nitrogen(N) and phosphorus(P) concentrations constrain photosynthetic and metabolic processes,growth and the productivity of plants. Their stoichiometry and scaling relationships regulate the allocation of N and P from subcellular to organism, and even ecosystem levels, and are crucial to the modelling of plant growth and nutrient cycles in terrestrial ecosystems. Prior work has revealed a general biogeographic pattern of leaf N and P stoichiometric relationships and shown that leaf N scales roughly as two-thirds the power of P. However, determining whether and how leaf N and P stoichiometries, especially their scaling exponents, change with functional groups and environmental conditions requires further verification. In this study, we compiled a global data set and documented the global leaf N and P concentrations and the N:P ratios by functional group, climate zone and continent. The global overall mean leaf N and P concentrations were 18.9 mg g^(-1) and 1.2 mg g^(-1), respectively, with significantly higher concentrations in herbaceous than woody plants(21.72 mg g^(-1) vs. 18.22 mg g^(-1) for N; and 1.64 mg g^(-1) vs. 1.10 mg g^(-1) for P). Both leaf N and P showed higher concentrations at high latitudes than low latitudes. Among six continents, Europe had the highest N and P concentrations(20.79 and 1.54 mg g^(-1)) and Oceania had the smallest values(10.01 and 0.46 mg g^(-1)). These numerical values may be used as a basis for the comparison of other individual studies. Further, we found that the scaling exponent varied significantly across different functional groups,latitudinal zones, ecoregions and sites. The exponents of herbaceous and woody plants were 0.659 and0.705, respectively, with significant latitudinal patterns decreasing from tropical to temperate to boreal zones. At sites with a sample size ≥10, the values fluctuated from 0.366 to 1.928, with an average of 0.841.Several factors including the intrinsic attributes of different life forms, P-related growth rates and relative nutrient availability of soils likely account for the inconstant exponents of leaf N vs. P scaling relationships.Di Tian Zhengbing Yan Karl J.Niklas Wenxuan Han Jens Kattge Peter B.Reich Yongkai Luo Yahan Chen Zhiyao Tang Huifeng Hu Ian J.Wright Bernhard Schmid Jingyun Fang 2018National Science Review2018,5,5:24
4士兵体能的测量和评价显示文摘本标准是在调查和分析2250名陆军士兵有氧能力、心肺功能、肌力、身体素质和运动能力等20余项体质参数的基础上制订的。该标准规定了男性士兵体能的评价等级,其中包括PWC_(170)、Vo_(2max)、肌力、台阶指数、身体素质和运动能力等参数的分级标准,适用于陆军和海、空军陆勤士兵的体能评价。Li Wenxuan(Institute of Hygiene and Environmental Medicine,Academy of Military Medical Sciences, Tianjin, 300050) 1995解放军预防医学杂志1995,13,3:20
5GC-MS, GC-O and OAV analyses of key aroma compounds in Jiaozi Steamed Bread显示文摘Jiaozi Steamed Bread(JSB)has a unique aroma as a traditional staple food in China.The volatile compounds in JSBwere extracted by simultaneous distillation and extraction(SDE)and headspace solid-phasemicroextraction(HS-SPME).These volatile substances were analyzed by gas chromatography-mass spectrometry(GC-MS)and gas chromatographyolfactometry-mass spectrometry(GC-O-MS).The results demonstrated that 61 volatile compounds were identified totally in samples,of which 15 were confirmed as potent aroma compounds with odor active values(OAVs)>1.The 15 potent aroma compounds were ethanol,1-butanol,1-pentanol,1-hexanol,heptanol,1-octen-3-ol,3-methyl-1-butanol,hexanal,heptanal,nonanal,(E)-2-heptenal,benzaldehyde,(E,E)-2,4-decadienal,2-pentylfuran and naphthalene.The SDEmethod had better linearity with coefficients of determination(R2)equal to or higher than 0.9991.Furthermore,the SDE method also achieved lower sensitivity and better repeatability and recovery than HS-SPME.This work provides reference method and parameters for future research on the flavor of JSB for commercial products.Yuanhui Wang Jingwen Zhao Fei Xu Xiaoyun Wu Wenxuan Hu Yongfeng Chang Lanlan Zhang Jie Chen Changhong Liu 2020Grain & Oil Science and Technology2020,3,1:17
6Advances in research of sulphide ore textures and their implications for ore genesis显示文摘在硫醚矿石质地在的研究的重要进展恨年加深了我们相关矿藏的矿石开始的理解。硫醚矿物质的压力答案为矿石材料的动员作为机制被建议了,而脉石的压力答案被相信提起主要矿石的等级。我们知道了从液体的贱金属硫醚的降水比较喜欢水晶和黄铁矿的裂缝表面形成增生。因此,在一个沉积序列的忍受黄铁矿的胚胎床能作为有效水晶种子床被扮演并且为套印形成巨大的 statabound 沉积物的液体是赞成的。各种各样的硫醚的质地研究能被用来解释矿石的沉积,成岩作用,变丑和变态的全部历史。在闪锌矿的黄铜矿疾病的学习引起了地区精制的想法,并且在巨大的硫醚沉积物把新解释给金属带状配列。硫醚矿石的可锻的砍可以形成矿石糜棱岩,它将成为在套印的迟了阶段的液体期间在 Cu, Au 和 Ag 充实的矿石射击。尽管有那,各种各样的现代分析技术很快正在被开发,是为矿石地质学家的一个 unreplaceable 工具的矿石显微镜学遗体。与这些现代技术结合了,这个工具将帮助在矿石开始上加速理论的发展。GU Lianxing ZHENG Yuanchuan TANG Xiaoqian WU Changzhi HU Wenxuan 2006Progress in Natural Science:Materials International2006,16,10:15
7Sensitivity analysis for probabilistic anti-resonance design of aeronautical hydraulic pipelines显示文摘In an uncertainty scheme, reliability and global sensitivity analysis is studied in this work, to provide helpful information for probabilistic anti-resonance design of vibration systems.Discussions show that the resonance failure problem can be viewed as a series system, in which input uncertainties are modeled by random variables. In order to quantitatively measure the contributions of input variables to the system reliability, a global sensitivity index is proposed, the properties of which are also discussed. Then the proposed index is tested with an aeronautical hydraulic pipeline system, which is under the excitation of pump vibration and at a risk of resonance failure. Sensitivity results under different failure criteria and variation coefficients are obtained and studied, from which significant and insignificant input variables can be identified.The proposed method provides a relatively new insight for anti-resonance design of engineering structures.Changcong ZHOU Zheng ZHANG Fuchao LIU Wenxuan WANG 2019Chinese Journal of Aeronautics2019,32,4:13
8Extracellular Signal-Regulated Kinase in Nucleus Accumbens Mediates Propofol Self-Administration in Rats显示文摘Clinical and animal studies have indicated that propofol has potential for abuse,but the specific neurobiological mechanism underlying propofol reward is not fully understood.The purpose of this study was to investigate the role of extracellular signal-regulated kinase(ERK) signal transduction pathways in the nucleus accumbens(NAc) in propofol self-administration.We tested the expression of p-ERK in the NAc following the maintenance of propofol self-administration in rats.We also assessed the effect of administration of SCH23390,an antagonist of the D1 dopamine receptor,on the expression of p-ERK in the NAc in propofol self-administering rats,and examined the effects of intra-NAc injection of U0126,an MEK inhibitor,on propofol reinforcement in rats.The results showed that the expression of p-ERK in the NAc increased significantly in rats maintained on propofol,and pre-treatment with SCH23390 inhibited the propofol selfadministration and diminished the expression of p-ERK in the NAc.Moreover,intra-NAc injection of U0126(4 μg/side) attenuated the propofol self-administration.The data suggest that ERK signal transduction pathways coupled with D1 dopamine receptors in the NAc may be involved in the maintenance of propofol self-administration and its rewarding effects.Benfu Wang Xiaowei Yang Anna Sun Lanman Xu Sicong Wang Wenxuan Lin Miaojun Lai Huaqiang Zhu Wenhua Zhou Qingquan Lian 2016Neuroscience Bulletin2016,32,6:12
9Effects of Deep Fluids on Hydrocarbon Generation and Accumulation in Chinese Petroliferous Basins显示文摘Deep fluids in a petroliferous basin generally come from the deep crust or mantle beneath the basin basement, and they transport deep substances(gases and aqueous solutions) as well as heat to sedimentary strata through deep faults. These deep fluids not only lead to large-scale accumulations of CO_2, CH_4, H_2, He and other gases, but also significantly impact hydrocarbon generation and accumulation through organic-inorganic interactions. With the development of deep faults and magmatic-volcanic activities in different periods, most Chinese petroliferous basins have experienced strong impacts associated with deep fluid activity. In the Songliao, Bohai Bay, Northern Jiangsu, Sanshui, Yinggehai and Pearl Mouth Basins in China, a series of CO_2 reservoirs have been discovered. The CO_2 content is up to 99%, with δ^(13)C_(CO2) values ranging from-4.1‰ to-0.37‰ and ~3He/~4He ratios of up to 5.5 Ra. The abiogenic hydrocarbon gas reservoirs with commercial reserves, such as the Changde, Wanjinta, Zhaozhou, and Chaoyanggou reservoirs, are mainly distributed in the Xujiaweizi faulted depression of the Songliao Basin. The δ^(13)CCH4 values of the abiogenic alkane gases are generally >-30‰ and exhibit an inverse carbon isotope sequence of δ^(13)C_(CH4)>δ^(13)C_(C2H6)>δ^(13)C_(C3H8)>δ^(13)C_(C4H10). According to laboratory experiments, introducing external H_2 can improve the rate of hydrocarbon generation by up to 147% through the kerogen hydrogenation process. During the migration from deep to shallow depth, CO_2 can significantly alter reservoir rocks. In clastic reservoirs, feldspar is easily altered by CO_2-rich fluids, leading to the formation of dawsonite, a typical mineral in high CO_2 partial pressure environments, as well as the creation of secondary porosity. In carbonate reservoirs, CO_2-rich fluids predominately cause dissolution or precipitation of carbonate minerals. The minerals, e.g., calcite and dolomite, show some typical features, such as higher homogenization temperatures than the burial temperature, relatively high concentrations of Fe and Mn, positive Eu anomalies, depletion of 18 O and enrichment of radiogenic ^(87)Sr. Due to CO_2-rich fluids, the development of high-quality carbonate reservoirs is extended to deep strata. For example, the Well TS1 in the northern Tarim Basin revealed a high-quality Cambrian dolomite reservoir with a porosity of 9.1% at 8408 m, and the Well ZS1 C in the central Tarim Basin revealed a large petroleum reserve in a Cambrian dolomite reservoir at ~6900 m. During the upward migration from deep to shallow basin strata, large volumes of supercritical CO_2 may extract petroleum components from hydrocarbon source rocks or deep reservoirs and facilitate their migration to shallow reservoirs, where the petroleum accumulates with the CO_2. Many reservoirs containing both supercritical CO_2 and petroleum have been discovered in the Songliao, Bohaiwan, Northern Jiangsu, Pearl River Mouth and Yinggehai Basins. The components of the petroleum trapped with CO_2 are dominated by low molecular weight saturated hydrocarbons.ZHU Dongya LIU Quanyou JIN Zhijun MENG Qingqiang HU Wenxuan 2017Acta Geologica Sinica(English Edition)2017,91,1:12
10Value of diffusion-weighted imaging in distinguishing pancreatic carcinoma from mass-forming chronic pancreatitis: a meta-analysis显示文摘Niu Xiangke Sushant Kumar Das Anup Bhetuwal Xiao Yingquan Sun Feng Zeng Lichuan Wang Wenxuan Yang Hanfeng Yang Hanyu 2014Chinese Medical Journal2014,,19:11
11Enhanced vasoconstriction to α_1 adrenoceptor autoantibody in spontaneously hypertensive rats显示文摘Autoimmune activities have been implicated in the pathogenesis of hypertension.High levels of autoantibodies against the second extracellular loop of α1-adrenoceptor(α1-AR autoantibody,α1-AA) are found in patients with hypertension,and α1-AA could exert a α1-AR agonist-like vasoconstrictive effect.However,whether the vasoconstrictive effect of α1-AA is enhanced in hypertension is unknown.Using aortic rings of spontaneously hypertensive rats(SHR) and normotensive Wistar-Kyoto(WKY) rats,we observed the vasoconstrictive responses to α1-AA with phenylephrine(α1-AR agonist) as a positive control drug.Aortic nitrotyrosine levels were also measured by ELISA and immunohistochemistry.The results showed that the aortic constrictive responses to α1-AA and phenylephrine(both 1 nmol L-1-10 μmol L-1) were greater in SHR than in WKY rats.Endothelial denudation or L-NAME(a non-selective NOS inhibitor)(100 μmol L-1) increased α1-AA- or phenylephrine-induced vasoconstrictions both in SHR and WKY.However,selective iNOS inhibitor 1400W(10 μmol L-1) enhanced the α1-AA-induced aortic constriction in WKY,but not in SHR.The aortic nitrotyrosine level was significantly higher in SHR than WKY,as shown by both ELISA and immunohistochemistry.These results indicate that the vasoconstrictive response to α1-AA is enhanced in SHR,and this altered responsiveness is due to endothelial dysfunction and decreased NO bioavailability.The study suggests an important role of α1-AR autoimmunity in the pathogenesis and management of hypertension especially in those harboring high α1-AA levels.YAN Li TAN XiaoQiu CHEN WenXuan ZHU Hong CAO JiMin LIU HuiRong 2014Science China(Life Sciences)2014,57,7:10
12Recent advances in the improvement of g-C_(3)N_(4) based photocatalytic materials显示文摘g-C_(3)N_(4) have been widely used in the fields of photocatalytic hydrogen production,photocatalytic degradation of dyes and oxidative degradation of toxic gases due to their excellent performance.It has attracted extensive attention in recent years due to its highly efficient photocatalytic capacity of hydrogen generation,water oxidation,carbon dioxide reduction and degradation of organic pollutants.Because of the abundant carbon and nitrogen composition of the earth,large-scale production and industrial applications of this material are possible.The modification of this material makes its performance more excellent so that this new material can obtain a steady stream of vitality.These outstanding works have become important materials and milestones on the road to mankind's photocatalytic hydrogen production.This review will begin with the basic idea of designing,synthesizing and improving g-C_(3)N_(4) based photocatalytic materials,and introduce the latest development of g-C_(3)N_(4) photocatalysts in hydrogen production from four aspects of controlling the carbon/nitrogen ratio,morphology,element doping and heterojunction structure of g-C_(3)N_(4) materials.Yupeng Xing Xiaoke Wang Shuhua Hao Xueli Zhang Xiao Wang Wenxuan Ma Gang Zhao Xijin Xu 2021Chinese Chemical Letters2021,32,1:10
13CO_2 Density-Raman Shift Relation Derived from Synthetic Inclusions in Fused Silica Capillaries and Its Application显示文摘The densities of CO_2 inclusions in minerals are commonly used to determine the crystallizing conditions of the host minerals.However,conventional microthermometry is difficult to apply for inclusions of small size(<5-10μm) or low density.Raman analysis is an alternative method for determining CO_2 density,provided that the CO_2 density-Raman shift relation is known.This study aims to establish this CO_2 density-Raman shift relation by using CO_2 inclusions synthesized in fused silica capillaries.By using this newly-developed synthetic technique,we formed pure CO_2 inclusions,and their densities were determined by microthermometry.The Raman analysis showed that the relation between CO_2 density(D in g/cm3) and the separations(△in cm^(-1)) between the two main bands(i.e.Fermi diad bands) in CO_2 Raman spectra can be represented by a cubic equation:D (g/cm^3)=0.74203(-0.019⊿~3+5.90332⊿~2-610.79472⊿+21050.30165)-3.54278(r^2=0.99920).Our calculated D value for a given⊿ is between those obtained from two previously-reported equations,which were derived from different experimental methods.An example was given in this study to demonstrate that the densities of natural CO_2 inclusions that could not be derived from microthermometry could be determined by using our method.SONG Yucai CHOU I'Ming HU Wenxuan Burruss ROBERT LU Wanjun 2009Acta Geologica Sinica(English Edition)2009,83,5:9
14Detection of water in petroleum inclusions and its implications显示文摘FTIR spectra of inclusions sampled from fault-zone reservoirs of the northwestern Junggar Basin show that water, with different abundances, does exist in petroleum inclusions. It is thus implied that petroleum inclusions can seldom form without water. Different inclusions hosted in one single grain, and formed in one oil charging phase, have a largely varied ratio of water to oil and slightly changed CH3/CH2 ratio. This likely provides evidence for fault-related episodic migration and accumulation of hydrocarbons.CAO Jian YAO Suping HU Wenxuan ZHANG Yijie WANG Xulong ZHANG Yueqian TANG Yong 2006Chinese Science Bulletin2006,51,12:9
15Regional moment-independent sensitivity analysis with its applications in engineering显示文摘Traditional Global Sensitivity Analysis(GSA) focuses on ranking inputs according to their contributions to the output uncertainty.However,information about how the specific regions inside an input affect the output is beyond the traditional GSA techniques.To fully address this issue,in this work,two regional moment-independent importance measures,Regional Importance Measure based on Probability Density Function(RIMPDF) and Regional Importance Measure based on Cumulative Distribution Function(RIMCDF),are introduced to find out the contributions of specific regions of an input to the whole output distribution.The two regional importance measures prove to be reasonable supplements of the traditional GSA techniques.The ideas of RIMPDF and RIMCDF are applied in two engineering examples to demonstrate that the regional moment-independent importance analysis can add more information concerning the contributions of model inputs.Changcong ZHOU Chenghu TANG Fuchao LIU Wenxuan WANG Zhufeng YUE 2017Chinese Journal of Aeronautics2017,30,3:8
16Family-level leaf nitrogen and phosphorus stoichiometry of global terrestrial plants显示文摘Leaf nitrogen(N) and phosphorus(P) concentrations are critical for photosynthesis, growth, reproduction and other ecological processes of plants. Previous studies on large-scale biogeographic patterns of leaf N and P stoichiometric relationships were mostly conducted using data pooled across taxa, while family/genus-level analyses are rarely reported. Here, we examined global patterns of family-specific leaf N and P stoichiometry using a global data set of 12,716 paired leaf N and P records which includes 204 families, 1,305 genera, and 3,420 species. After determining the minimum size of samples(i.e., 35 records), we analyzed leaf N and P concentrations, N:P ratios and N^P scaling relationships of plants for 62 families with 11,440 records. The numeric values of leaf N and P stoichiometry varied significantly across families and showed diverse trends along gradients of mean annual temperature(MAT) and mean annual precipitation(MAP). The leaf N and P concentrations and N:P ratios of 62 families ranged from 6.11 to 30.30 mg g–1, 0.27 to 2.17 mg g–1, and 10.20 to 35.40, respectively. Approximately 1/3–1/2 of the families(22–35 of 62) showed a decrease in leaf N and P concentrations and N:P ratios with increasing MAT or MAP, while the remainder either did not show a significant trend or presented the opposite pattern. Family-specific leaf N^P scaling exponents did not converge to a certain empirical value, with a range of 0.307–0.991 for 54 out of 62 families which indicated a significant N^P scaling relationship. Our results for the first time revealed large variation in the family-level leaf N and P stoichiometry of global terrestrial plants and that the stoichiometric relationships for at least one-third of the families were not consistent with the global trends reported previously. The numeric values of the family-specific leaf N and P stoichiometry documented in the current study provide critical synthetic parameters for biogeographic modeling and for further studies on the physiological and ecological mechanisms underlying the nutrient use strategies of plants from different phylogenetic taxa.Di Tian Zhengbing Yan Suhui Ma Yuehong Ding Yongkai Luo Yahan Chen Enzai Du Wenxuan Han Emoke Dalma Kovacs Haihua Shen Huifeng Hu Jens Kattge Bernhard Schmid Jingyun Fang 2019Science China(Life Sciences)2019,62,8:7
17Using in situ REE analysis to study the origin and diagenesis of dolomite of Lower Paleozoic,Tarim Basin显示文摘In situ REE concentrations of various dolomites from Tarim Basin were obtained by LA-ICP-MS analysis,and the data were normalized to standard seawater(Seawater Normalized=SWN).Most of the samples have a ΣREE range of less than 20 ppm.All samples show similar REESWN distributions with heavy REE depletion,and positive Ce anomaly,which indicates that they have the same dolomitization fluids(seawater).According to the origin and diagenetic process of dolomite,two types of dolomite are determined and described as follows:1) syndepositional dolomite,with the highest REE concentrations(more than 20 ppm),the cores of which are more enriched in REE compared with their cortexes,indicating that they underwent the dolomitization of calcareous sediments by hypersaline and subsequent diagenesis decreased the REE content of the cortex because of the low REE concentration of the diagenetic fluids;2) diagenetic dolomite,which can be subdivided into four groups.(1) burial dolomite which has higher REE concentrations than limestone,but lower than syndepositional dolomite.This shows that pore fluids with high salinity dolomitized the pre-existing limestone;(2) void filling dolomite which has the similar REE patterns with the matrix dolomite.In addition,the Eu anomaly is not obvious,suggesting that the dolomitization fluids originated from the diagenetic fluids;(3) recrystallized dolomite,whose REE concentration was obviously decreased,indicating that the REE concentration was decreased during the recrystallization processes;and(4) hydrothermal altered void-filling dolomite,which has the lowest REE concentration,but obvious positive Eu anomaly,reflecting its hydrothermal activity related origin.Thus,the diverse REE signatures,which were recorded in different dolomites,retain the information of their formation conditions and subsequent diagenetic processes.In situ REE analysis of dolomite is an effective probe into the origin and diagenetic process of dolomite.WANG XiaoLin JIN ZhiJun HU WenXuan ZHANG JunTao QIAN YiXiong ZHU JingQuan LI Qing 2009Science China Earth Sciences2009,52,5:7
18Discovery of low-mature hydrocarbon in manganese nodules and ooze from the Central Pacific deep sea floor显示文摘Extracts from manganese nodules and ooze from the Central Pacific deep sea floor were analyzed using the chromatogram-mass spectrum, and it was found that most of the biomarker molecules are of the low-mature type (some have characteristics of mature): the ratio of 'A'/C is high between 11.4%-19.75%; CPI is 1.22-1.23; C31-22S/ (22S+22R) hopane is 0.59-0.60, Tm/Ts is 0.99-1.99; pa moretane/(αβ+βα) hopane is 0.12-0.14; C29 sterane 20S/(20S+20R) is 0.35-0.41; ββ/(ββ+αα) is 0.38-0.45; arene TA(I)/TA(I+Ⅱ) is 0.16-0.21; methyl-phenanthrene index (MPI1) is 0.35-0.67. According to the geological settings of the sampling area and its organic geochemical characteristics, it is considered that the hydrothermal activities on the ocean floor facilitate the decomposition of organic matter in the sediment, which leads to the generation and migration of hydrocarbon into manganese nodules and ooze. This discovery is important for understanding the mechanisms of hydrocarbon generation in the ocean floor andHU Wenxuan JIN Zhijun YAO Suping LU Xiancai CHEN Zhilin ZHANG Linye ZHANG Xuejun ZHOU Huaiyang 2002Chinese Science Bulletin2002,47,11:7
19Noble gases in corundum megacrysts from the basalts in Changle,Shandong Province,eastern China显示文摘This study presents noble gaseous data of the corundum megacrysts from the Cenozoic basalts in Changle, Shandong Province, eastern China. It is known that no noble gaseous data of corundum megacryst have been documented before. The 3He/4He ratios (1.13-7.37 Ra) of the corundums from Changle vary from atmosphere to MORB values; the 20Ne/22Ne (9.67-10.75) and 21Ne/22Ne (0.0280-0.0372) data define two linear trends on Ne three-isotope diagram, respectively, along the MFL and the correlation line between atmosphere and MORB; the 38Ar/36Ar (0.177-0.194) ratios, the 40Ar/36Ar (280.9 -404.2) ratios and the 128-136Xe/132Xe ration with obvious 129Xe excess are generally higher than at-mospheric component, but the 40Ar/36Ar ratios are much closer to atomospheric ratio. The isotopic compositions of noble gases (particularly for He and Ar) of the corundums are similar to those of py-roxene, anorthoclase megacrysts, and mantle-derived xenoliths from this area, and those of man-tle-derived xenoliths from several areas in eastern China. Therefore, the noble gases trapped in the corundums probably are from mantle source, representing a ‘mixed fluid' produced by the interaction between the lithospheric mantle and fluids releasing from the convective plate. Both the noble gas isotopic compositions and the oxygen isotopic compositions of the solid corundums are not the characteristics of crustal source. These suggest that the corundums crystallized from mantle-derived magmas with minimal crustal contamination.HU WenXuan SONG YuCai CHEN XiaoMing TAO MingXin ZHANG LiuPing 2007Chinese Science Bulletin2007,52,3:6
20Localized salt accumulation: the main reason for cotton root length decrease during advanced growth stages under drip irrigation with mulch film in a saline soil显示文摘High salinity in soil can prevent root growth of most plants. To investigate soil salinity dynamics under drip irrigation with mulch film(DI) and its effects on cotton root length, we conducted field experiments in saline soil based on a monolith method using flooding irrigation with mulch film(FI) as a control at the Korla Experimental Station of the Xinjiang Academy of Agricultural Sciences, China in 2009 and 2010. The results showed that the total root length decreased 120 days after sowing(DAS) under DI, and was mainly centered in the 0–30 cm soil layer and at distances of 30–70 cm from the drip-lines. There was almost complete overlap in the area of root length decline and salt accumulation. In the soil depth of 0–30 cm and at distances of 30–70 cm from the drip-lines at 110 to 160 DAS in 2009 and 171 DAS in 2010, the electrical conductivity(EC) in all soil samples was at least 3 mS/cm and in some cases exceeded 5 mS/cm under DI treatment. However, EC barely exceeded 3 mS/cm and no reduc- tion in root length was observed under FI treatment. Correlation analysis of soil EC and root length density indicated that the root length declined when the soil EC exceeded 2.8 mS/cm. The main reason for the decrease of root length in cotton under DI was localized accumulation of salinity.WenXuan MAI ChangYan TIAN Li LI 2014Journal of Arid Land2014,6,3:6
返回顶部 每页显示:
共13页 首页 上一页 第1页 下一页 末页 /13 跳转

网站首页 | 关于我们 | 联系我们 | 产品服务 | 客服中心 | 广告服务 | 版权声明 | 网站联盟 | 友情链接 | 售卡网点

版权所有© 渝B2-20050021-1 渝公网安备 50019002500403号 违法和不良信息举报中心

互联网出版许可证 新出网证(渝)字10号 全国400电话 - 免长途话费