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Physical mechanisms of plant roots affecting weathering and leaching of loess soil

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Science china Earth sciences 2006年第9期49卷 1002-1008页

作者： LI Yong1,2. ZHANG Qingwen1,2. WAN Guojiang3, HUANG Ronggui3, PIAO Hechun3, BAI Lingyu2.& LI Lu2.1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, chinese academy of sciences, Yangling 712.00, china 2. Institute of Agro-Environment and Sustainable Development, {2. academy of Agricultural sciences, Beijing 100081, china 3. Institute of Geochemistry, chinese academy of sciences, Guiyang 550002. china 1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Chinese Academy of Sciences Yangling 712100 China 2. Institute of Agro-Environment and Sustainable Development Chinese Academy of Agricultural Sciences Beijing 100081 China 3. Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

Plant roots have potential impacts on soil mineral weathering and *** objective is to understand the physical mechanisms of plant roots affecting weathering andleaching of loess soil. Root densities were measured through the method of a large-size dug profile,and transport fluxes of soil elements were determined using an undisturbed monolith soilinfiltration device on the hilly and gully regions of the chinese Loess Plateau. The results showthat the improvement effects of soil environment by plant roots are mainly controlled by the densityand weight of the fibrous roots with the diameters less than 1 mm. Plant roots have the strongereffects on soil physical properties than chemical properties. The principal components analysis(PCA) indicates that soil physical properties by plant roots account for 56.7% of variations in soilenvironment whereas soil chemical properties and pH contribute about 2..2. of the soil *** roles of plant roots in controlling soil weathering and leaching increased in the followingorder: infiltration enhancement > increase of bio-active substance > stabilization of soilstructure. The effects of plant roots on soil mineral weathering and leaching can be quantifiedusing the multiple regression models with the high prediction accuracies developed in this study.

关键词： plant roots, soil weathering and leaching rates, soil environment field, principal components analysis (PCA), chinese Loess Plateau.

Syntheses of Clusters Containing C2.2.M=Co,Mo）Cores and Crystal Structure of 〔dpp〕〔Mo2.p2.CO）4〕·CH2.l2

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chinese Journal of Structural Chemistry 1999年第4期18卷 35-40页

作者： CHEN XueNian ZHANG Jie YIN YuanQi (State Key Laboratory for Oxo Synthesis and Selective Oxidation,lanzhou Institute of chemical {2., the chinese academy of sciences, lanzhou 730000)ZSUN Jie (Shanghai Institute of Organic Chemistry, the chinese Acad State Key Lab. Oxo Synthesis S. Lanzhou Inst. of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China Shanghai Inst. of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China

１ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｅｘｔｅｎｓｉｖｅａｎｄｒａｐｉｄｄｅｖｅｌｏｐｍｅｎｔｏｆｔｈｅｃｈｅｍｉｓｔｒｙｏｆｄｉｎｕｃｌｅａｒｔｒａｎｓｉｔｉｏｎｍｅｔａｌｃｏｍｐｌｅｘｅｓｂｒｉｄｇｅｄｂｙｕｎｓａｔｕ... 详细信息

１ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｅｘｔｅｎｓｉｖｅａｎｄｒａｐｉｄｄｅｖｅｌｏｐｍｅｎｔｏｆｔｈｅｃｈｅｍｉｓｔｒｙｏｆｄｉｎｕｃｌｅａｒｔｒａｎｓｉｔｉｏｎｍｅｔａｌｃｏｍｐｌｅｘｅｓｂｒｉｄｇｅｄｂｙｕｎｓａｔｕｒａｔｅｄｈｙｄｒｏｃａｒｂｏｎｓ...

关键词： cobalt molybdenum diyne compounds crystal structure cluster

Enantioselective Hydrogenation of α,β-Unsaturated Cyclic Ketones by Double Asymmetric Induction Preparation of (R)-Muscone

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chinese chemical Letters 1997年第6期8卷 477-478页

作者： Bao Han XIE Shi Jie LU Hong Xiang FU Lan Yong GAO (State Key Laboratory for Oxo Srnthesis and Selective Oxidation lanzhou Institute of chemical {2.. chinese academy of sciences, lanzhou 730000) chinese ACAD SCI LANZHOU INST CHEM PHYSSTATE KEY LAB OXO SYNTH & SELECT OXIDATLANZHOU 730000PEOPLES R CHINA

By ketal formation with chiral glycols like methyl or ethyl ester of tartaric acid,hydrogenation of ketals from the correspondingα,β-unsaturated 15-membered cyclic ketone produces (R)-muscone in good chemical and op... 详细信息

关键词： Unsaturated Cyclic Ketones by Double Asymmetric Induction Preparation of Muscone

Relation between texture and chemical composition of peridotite xenoliths and its implications: An example from Wangqing, Jilin Province

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chinese Science Bulletin 1998年第10期43卷 837-840页

作者： XU Yigang Guangzhou Institute of Geochemistry, chinese academy of sciences, Guangzhou 510640, china Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China

Spinel peridotite xenoliths from Wangqing, NE china exhibit correlative variations in texture, temperature, geochemistry and radiogenic isotopes. This suggests that the Wangqing xenoliths may come from a mantle diapir. It is possible that the fertile and undeformed lherzolites were situated in the interior of the diapir, whereas the refractory and deformed harzburgites and clinopyroxene_poor lherzolites were within the diapiric flanks.

关键词： peridotite xenoliths texture geochemistry Wangqing.

INVESTIGATION OF THE ACTIVE PHASE OF Ag_xSb_yO_z/SiO_2.CATALYST FOR THE CONDENSATION OF ISOBUTENE AND FORMALDEHYDE INTO ISOPRENE

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分子催化 1989年第S1期3卷 42-50页

作者： An Lidun, Jiang Zhicheng and Yin Yuangen (lanzhou Institute of chemical {2., chinese academy of sciences, lanzhou, china)

chemical Composition,surface distribution of the elements and crystal structure offresh and deactivated AgxSbyOz/SiO2.catalysts were investigated investigated by X-ray photoelectronspectroscopy（XPS）,scanning Auger m... 详细信息

chemical Composition,surface distribution of the elements and crystal structure offresh and deactivated AgxSbyOz/SiO2./sub> catalysts were investigated investigated by X-ray photoelectronspectroscopy（XPS）,scanning Auger microprobc（SAM）,electron microdiffraction（EMD）and atomic absorption spectroscopy（AAS）.From the experimental results that in-clude the activity evaluation of model catalyst Sb2./sub>O4/SiO2./sub> Which Shows the inertness ofSb2./sub>O4 in Prins reaction,it is reasonable to infer that the active phase ofAgxSbyOz/SiO2./sub> catalyst for Prins condensation reaction seems to be cubic AgSbO3.Thereason of the deactivation of the catalyst was *** is suggested that silver componentseems to be unstable in this catalyst.

关键词： silver cubic unstable crystalline condensation Electron dispersed photoelectron spectrometer spacing

INVESTIGATION OF THE SURFACE CHARACTERISTICS AND CATALYTIC ACTIVITY OF Sb_xO_y/SiO_2.ATALYSTS FOR VAPOR-PHASE SYNTHESIS OF ISOPRENE FROM ISOBUTYLENE AND FORMALDEHYDE

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分子催化 1989年第S1期3卷 66-71页

作者： Dang Zhongyuan, Ding Shixing (lanzhou Institute of chemical {2., chinese academy of sciences, lanzhou, china.)

The surface characteristics and catalytic activity of SbxOY/ SiO2.catalysts forvapor-phasc synthesis of isoprene from isobutylene and formaldehyde have been investi-gated by TPR, XRD, XPS, IR and catalytic activity ev... 详细信息

The surface characteristics and catalytic activity of SbxOY/ SiO2./sub> catalysts forvapor-phasc synthesis of isoprene from isobutylene and formaldehyde have been investi-gated by TPR, XRD, XPS, IR and catalytic activity evaluation. The results show that whenthe Sb loadings are less than about 5 wt%,SbxOY is compIctely dispersed on the surface ofsilica to form a surface compound with Sb（V）=O group and the catalysts have relativelyhigh catalytic activity; when the Sb loadings are more than 5 wt%, in addition to this surfacccompound, the crystalline α-Sb2./sub>O4 is formed on the support surface and causes rapid de-crease of catalytic activity. It is suggcsted that the catalytic activity of SbxOY /siO2./sub> catalystsresults from synetgistic catalysis of the surface compound Sb（V）=O as the basic sites andthe surface silanol Si-OH as the acidie sites. The mechanism of this synergistic catalysis forisoprene production is discussed.

关键词： SURFACE dispersed crystalline silica gated catalysis synergistic spectrometer photoelectron crease

Separation of Ephedrines Using 1-Butyl-3-methylimidazolium-tetrafluoroborate Ionic Liquids as Eluent in High-performance Liquid Chromatography (HPLC)

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chinese chemical Letters 2003年第6期14卷 603-604页

作者： Li Jun HE, Wen Zhu ZHANG, Bo WEN, Xia LIU, Sheng Xiang JIANG* lanzhou Institute of chemical {2., chinese academy of Science, lanzhou 730000 lanzhou Inst. of chemical {2. Chinese Academy of Science Lanzhou 730000 China

A simple, effective HPLC method for separation of ephedrines was achieved by using 1-butyl-3-methylimidazolium-tetrafluoroborate ionic liquid solution (0.1% v/v) as eluent at pH 3.0. The involved mechanism may be due to that the imidazolium cations can effectively shield the silanol groups of alkylsilica surface, thereby decreasing band tailing and increasing the separation efficiency.

关键词： Ionic liquid ephedrine HPLC.

Interfacial behaviors of PMMA-PEO block copolymers at the air/water interface

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Science china Chemistry 2005年第6期48卷 567-573页

作者： CHENG Caixia1, JIAO Tifeng2. TANG Rupei1, LIU Minghua2.& XI Fu1 1. State Key Laboratory of Polymer physics and Chemistry, Joint Laboratory of Polymer Science and Materials, Institute of Chemistry, chinese academy of sciences, Beijing 100080, {2. 2. CAS Key Laboratory of Colloid and Interface Science, Institute of Chemistry, chinese academy of sciences, Beijing 100080, {2. 1. State Key Laboratory of Polymer physics and Chemistry Joint Laboratory of Polymer Science and Materials Institute of Chemistry Chinese Academy of Sciences 100080 Beijing China 2. CAS Key Laboratory of Colloid and Interface Science Institute of Chemistry Chinese Academy of Sciences 100080 Beijing China

Diblock copolymer of PMMA2.1-b-PEO114 and triblock copolymer of PMMA12.-b- PEO2.7-b-PMMA12. were synthesized and their interfacial properties at the air-water interface were investigated, where both blocks of polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA) are surface active but the former is soluble in water while the latter is not. Both the block copolymers could form monolayers with two obvious transition regions. The first transition point is around 10 mN/m, which could be assigned to the pancake-brush change of the PEO chains. The other is around 18 mN/m, which could be ascribed to the condensed packing of PMMA. The surface morphological changes during the compression of the Langmuir monolayers are inves-tigated by using the AFM and SEM methods for the films deposited at different surface pressure or molecular areas. At a lower surface pressure, a typical morphology of PEO-con- taining lipopolymers is observed. Upon compression, sphere-dominant morphologies were observed. While the diblock copolymer is easy to folding, the triblock copolymer is in favor of formation of circular domains through vesiculation.

关键词： PMMA-PEO, block copolymers, monolayer, Langmuir-Blodgett films, AFM.

Microwave Effect on Selective Oxidation of Toluene to Benzoic Acid over Modified V2.5/TiO2

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分子催化 1997年第5期 4-5页

作者： LIU Ye LIU Pu GAO Runxiong ZHAO Zhuanyun YIN Yuanqi 1) (lanzhou Institute of chemical {2. The chinese academy of sciences lanzhou 730000)

ＭｉｃｒｏｗａｖｅＥｆｅｃｔｏｎＳｅｌｅｃｔｉｖｅＯｘｉｄａｔｉｏｎｏｆＴｏｌｕｅｎｅｔｏＢｅｎｚｏｉｃＡｃｉｄｏｖｅｒＭｏｄｉｆｉｅｄＶ２Ｏ５／ＴｉＯ２ＬＩＵＹｅＬＩＵＰｕＧＡＯＲｕｎｘｉｏｎｇＺＨＡＯＺｈｕａｎｙ... 详细信息

ＭｉｃｒｏｗａｖｅＥｆｅｃｔｏｎＳｅｌｅｃｔｉｖｅＯｘｉｄａｔｉｏｎｏｆＴｏｌｕｅｎｅｔｏＢｅｎｚｏｉｃＡｃｉｄｏｖｅｒＭｏｄｉｆｉｅｄＶ２Ｏ５／ＴｉＯ２ＬＩＵＹｅＬＩＵＰｕＧＡＯＲｕｎｘｉｏｎｇＺＨＡＯＺｈｕａｎｙｕｎＹＩＮＹｕａｎｑｉ１）（Ｌａｎ...

关键词： Microwave V 2. 5/TiO 2 Toluene Catalytic oxidation Benzoic acid