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Nitric Oxide Emission Following Wetting of Dry Soils in Subtropical Humid Forests

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Pedosphere 2009年第6期19卷 692-699页

作者： LI De-Jun and WANG Xin-Ming 2.state key {2. of Organic {2., Guangzhou institute of geochemistry, chinese academy of sciences, Guangzhou 510640 (China) state key {2. of Organic {2. Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 (China)

Information about soil nitric oxide （NO） emissions from subtropical forests is quite limited, and even less is known about the pulse emission of NO when wetting soils after a long period of dryness. In this study, we measured NO fluxes following wetting of dry soft in a broadleaf forest and a pine forest in subtropical China. Large pulses of NO fluxes were observed after soil wetting in both forests. NO fluxes increased significantly within 0.5 h following wetting in both forests and reached peak 1 and 4 h after soil wetting in the pine forest and the broadleaf forest, respectively. In the broadleaf forest, averaged peak flux of NO pulses was 157 ng N m^-2.s^-1, which was 8 times the flux value before wetting, and in the pine forest, the averaged peak flux was 135 ng N m-2.s 1, which was 15.5 times the flux value before wetting. The total pulses-induced NO emissions during the dry season were roughly estimated to be 2..4 mg N m^-2.in the broadleaf forest and 2..2.mg N m^-2.in the pine forest or made up a proportion of 4.6% of the annual NO emission in the broadleaf forest and 5.3% in the pine forest.

关键词： dry season flux. NO. pulse subtropical China

Metallogenic mechanisms of super-large Cu and Au deposits in the Dexing region and simulating experiments

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chinese Journal Of geochemistry 2010年第1期29卷 1-14页

作者： WU Xueyi and WANG Zijiang The state key {2. of Ore Deposit {2.,institute of {2.,chinese academy of sciences,guiyang 55002.China The state key {2. of Ore Deposit {2. Institute of Geochemistry Chinese Academy of Sciences Guiyang China

Based on the results of previous studies and under the direction of the theory of "ore deposit genesis",the authors made use of high temperature and high pressure experimental facilities and conditions at the Tectono-geochemistry Research Room under the state {2. {2. of Ore Deposit geochemistry,institute of geochemistry,chinese academy of sciences,and put the focus on the multi-source of tectonically controlling ore-forming materials,the characteristics of multi-stage and multi-episode hydrothermal activities and mineralization and the characteristics of multi-genesis and multi-ore deposition so as to shed light on the metallogenic mechanisms of super-large Cu and Au *** addition simulating experiments were made on multi-stage and multi-episode tectonic activities and rock and ore deformation,multi-stage and multi-episode tectonic activities and mobilization and migration of ore-forming materials,and multi-stage and multi-episode tectonic activities and superimposition and enrichment of ore-forming *** experimental results showed that under the action of multi-stage and multi-episode tectonic stress the deformation and fragmentation of not only rocks and ores have been intensified,and but also the ore-forming materials originally disbursed in the rocks and ores have been mobilized and migrated and superimposed and *** experimental results also provided the scientific experimental data and grounds for deep-going research on the rules of metallogenesis and geneses of super-large ore deposits in the Dexing region,Jiangxi Province.

关键词：成矿机制模拟实验德兴地区金矿床超大型构造地球化学成矿物质来源国家重点实验室

Distribution characteristics of iodine in humic acid-high underground water in Inner Mongolia and their relations to IDD disease

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chinese Science Bulletin 1999年第S2期44卷 85-86页

作者： YU Xiaoying state key {2. of {2. geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002. China state key {2. of {2. geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

THE concentrations of iodine in humic acid-high underground water are not low, but the IDD disease isprevailing in some areas and no such disease is reported in some other areas. In order to explore the causes of disease and the factors affecting the concentrations of I in underground water, the author collected51 water samples from the Amengbayingmaodao Farm, Langshan Town, Linghe City of Bameng, ShibaTown of Wuyuan County, Qingshan Town of Wulatiehou Prefecture, and Zhijiliang Village in the suburbsof Hohhot City in the central and western part of Inner Mongolia for investigation. The analytical resultsshow that the water samples were relatively alkaline （pH=7.91 on average）. The average concentrationsof cations vary in the order of Na+>Ca2.> Mg2.>K+ while those of anions follow the decreasing

关键词： iodine humic acid distribution characteristics.

Trace elemental behavior during chemical weathering: A case study of biotite-granitic weathering profile in Longnan, Jiangxi Province, China

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chinese Science Bulletin 1999年第S2期44卷 130-132页

作者： MA Yingjun and LIU Congqiang state key {2. of {2. geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002. China state key {2. of {2. geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

THE study of chemical weathering processes can provide significant insight into not only the behavior ofmigration, deposition and accumulation of REEs and other elements (e.g. Au, Fe, Al ), but also themechanism of material cycle on the surface of the earth, especially the relationship between detrital sediments and provenance. Lateritic profiles are widespread in southern China, where two kinds of valuable supergene deposit occur. One is "ion-adsorbed" REE ore deposit; the other is lateritic gold ore deposit. This study is to investigate the mobility and fractionation of major and trace elements and mineralogical variations during chemical weathering of biotite granite in Longnan, Jiangxi Province, China, andto provide significant data for a better understanding of the relationships between weathering of

关键词： chemical weathering trace elements rare earth element fractionation biotite-granite.

Distribution and affecting factors of selenium in soil in the high-Se environment of Yutangba mini-landscape

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chinese Science Bulletin 1999年第S2期44卷 46-48页

作者： ZHU Jianming and ZHENG Baoshan state key {2. of {2. geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002. China state key {2. of {2. geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

SELENIUM is an indispensable trace element to human beings and normal animals but if found in excessively high dietary concentrations, it can cause poisoning. The most severe example of selenium poisoning occurred at Yutangba, a typical Se-rich area in China which is situated in the northern part of ShuangheTown about 81 km east of En’shi City of the southwestern Hubei Province and the only place in the worldwhere people suffered from selenosis. In this area selenium is present mainly in the carbonaceoussiliceous rocks and carbonaceous shales of the Upper Permian Maokou Formation 2.0 m north of the Yutangba area. Selenium concentrations in Se-rich carbonaceous siliceous rock samples collected byZheng and Song were estimated at 6 471 mg/kg and 8 390 mg/kg, respectively. However, Yang etal. once collected samples of stone coal in which the maximum Se concentration reached more

关键词： distribution affecting factors selenium soil Hubei.

The hydrogeochemistry of the Wujiang River drainage system in Guizhou, China (Ⅱ)——Variations in concentrations of dissolved trace elements in karst river water and their controlling factors

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chinese Science Bulletin 1999年第S2期44卷 112-115页

作者： LIU Congqiang and HAN Guilin state key {2. of {2. geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002. China state key {2. of {2. geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

GEOCHEMICAL studies of trace elements, especially heavy metal elements in river water will provide thegrounds for the assessment of the influence of human activities on the environment. At present, the stud- ies of water bodies in karst areas are focussed on the analysis of chemical compositions of surface and underground water samples, and almost no systematic study has been done on trace elements. So theauthors have carried out systematic studies on the distribution of concentrations of the dissolved trace elements and their controlling factors, while some systematic studies are under way on the major compositionsof river water in the Wujiang drainage system in Guizhou Province. On the basis of the characteristics ofthe U-Ca-Sr system in river water and their geochemical indicating implications (Refer to the paper entitled "The hydrogeochemistry of the Wujiang River drainage system in Guizhou, China: I. The U-Ca-Srsystem in karst river water"), the paper is concerned mainly with the trace element composition of

关键词： dissolved trace elements karst Wujiang River drainage system Guizhou China.

Two-stage correlation between pH and REE concentration and pattern in rivers

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chinese Science Bulletin 1999年第S2期44卷 106-107页

作者： WANG Zhongliang and LIU Congqiang state key {2. of {2. geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002. China state key {2. of {2. geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

DUE to the unique chemical coherence and slight systematic difference properties, the REEs are extensively used as tracers for origin and evolution of the earth and its geology compositions （involved naturalwaters）. Soluble REE concentration in rivers is very low (10-12./sup>), and has a typical heavy REE enrichedpattern relative to the North American Shale Composite （NASC） than those of upper crust, suspendedmaterials and sediments. Negative Ce anomalies were widely observed in most of rivers. The behavior of REE in rivers can be affected by geology and chemical weathering of drainage basin,concentration and species of colloids and organs, major anions, pH, microbe action and so on. Especially pH is an important factor controlling the chemistry of water

关键词： rivers REE pattern pH two-stage correlation.

Chemical weathering crust: A long-term storage of elements and its implications for sediment provenance

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chinese Science Bulletin 1999年第S2期44卷 107-110页

RAKE earth element (REE) and other trace element distributions in fine grained detrital sediments are widely used to characterize source composition of sediments, but ambiguities remain concerning theresponse of sediment composition (e.g. REEs) to provenance characteristics. One of the argumentsis whether significant amounts of REEs and other trace elements are likely to be stored in weathering profiles on the continents. Another ambiguity is which trace element ratios can be transferred with minimal changes from bedrock to weathering profiles and then to sediments. In addition, the effects oferosion and chemical weathering on the compositions of sediments remain poorly documented A major A major goal of this research is to investigate which elements are likely to be stored in weatheringprofiles, and to evaluate the effects of in situ chemical weathering and erosion on the compositions of siliciclastic sediments.

关键词： weathering profiles rare earth elements trace elemental ratios sediment provenance erosion.

Regulation mechanism of EM parameters in natural ferrite and its application in microwave absorbing materials

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Science China(Technological sciences) 2006年第1期49卷 38-49页

作者： ZHENG Yongchun1,2. WANG Shijie2. FENG Junming2. LI Chunlai1, OUYANG Ziyuan1,2. LIU Jianzhong1 & LI Xiaobiao2.1. National Astronomical Observatories, chinese academy of sciences, Beijing 100012. China 2. state {2. {2. of environmental geochemistry, institute of geochemistry, chinese academy of sciences, guiyang 550002. China National Astronomical Observatories Chinese Academy of Sciences Beijing China state key {2. of {2. geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang China

Electromagnetic (EM) parameters (ε ′, ε ″, μ ′, μ″ ) of several M2.Fe2.4 and Fe2.3 type natural ferrites with different geological occurrences are measured in this pa-per. The measurement results show that EM parameters of a magmatic-occurring natural ferrite is very different from other types occurring from sedimentary-metamorphic iron deposit, hydrothermal vein iron deposit, outer contact of magmatic iron deposit. It has potential to be used as magnetic absorbent in microwave absorbing materials. After min-eral separation and concentration, this magmatic-occurring natural ferrite was processed into type A ferrite absorbent. Type A natural ferrite absorbent is a kind of magnetic material with low dielectric constants, high magnetic conductivity and high EM loss. Its EM pa-rameters are ε ′ = 58.60, ε ″ = 10.0, μ ′ = 1.2.1.5, μ ″ = 1.0-1.2. respectively. In order to illuminate the regulation mechanism of EM parameters, we studied the chemical and mineral composition of type A ferrite absorbent. There is high concentration of natural impurities, which regulate the EM parameters of type A ferrite greatly. For comparison, the other types of natural ferrite, single-phase magnetite and two-phase iron minerals (ilmen-ite and magnetite), have few impurity. Thus regulation mechanism of EM parameters was absent in these ferrites. As a result, the regulation of EM parameters is advantageous to develop type A natural ferrite as excellent absorbent, lowers the reflectivity coefficients and enhances the absorbing efficiency of MAM made from it. Furthermore, the impurities in type A natural ferrite and its effects on EM parameters are very difficult to simulate in the synthesize ferrite. The carbonyl-iron powder is another kind of absorbent that is used ex-tensively in MAM. To compare the absorbing properties of these two absorbent, type A natural ferrite and carbonyl-iron powder were mixed with rubber and processed into mi-crowave absorbing sheets with the same procedures and tec

关键词： natural impure ferrite, complex permittivity, complex permeability, microwave absorbing materials.