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Pathways of birnessite formation in alkali medium

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Science china Earth Sciences 2005年第9期48卷 1438-1451页

作者： FENG Xionghan1, TAN Wenfeng1, LIU Fan1, HUANG Qiaoyun1 & LIU Xiangwen2.1. College of Resources and Environment, Huazhong Agricultural university, wuhan 430070,{2. 2. testing center, china university of geosciences, wuhan 430074,{2. College of Resources and Environment Huazhong Agricultural University Wuhan China testing center China University of Geosciences Wuhan China

Birnessite is a common weathering and oxidation product of manganese-bearing rocks. An O2.oxidation procedure of Mn(OH)2.in the alkali medium has been used to synthesize birnessite. Fast and powder X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), energy dispersed X-ray analysis (EDAX), infrared spectroscopy (IR) techniques and chemical composition analysis, Eh-pH equilibrium diagram approaches were employed to investigate the reaction process and pathways of birnessite formation. Results showed that the process of the birnessite formation could be divided into four stages: (1) forma- tion stage for hausmannite and feitknechtite, (2. stage of transformation of hausmannite and feitknechtite to buserite, (3) buserite crystal growing stage, and (4) stage of conversion of buser- ite into birnessite. Mn(OH)2.was mainly present as amorphous state only for a short initial time of oxidation reaction. In the oxidation process, buserite formed following two pathways by recrys- tallization after dissolution of the intermediates, and the transformations of the minerals de- pended on the Eh determined by the dissolved O2.concentration on their surfaces. The results are fundamental in further exploration on the mechanism of birnessite formation in the alkali medium. A great practical significance would also be expected with respect to the areas of mate- rial sciences.

关键词： birnessite, pathway of formation, reaction process, Eh-pH diagram, hausmannite, feitknechtite.

Weathered Mantle Hosted Gold Deposit atShewushan, Hubei, Central china

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Journal of china university of geosciences 2001年第1期12卷 60-67页

作者： Hong Hanlie Wang Qinyan The center for Material Research and testing, {2. university of Technology, {2. 430070 Bian Qiujuan Faculty of Earth Sciences, china university of geosciences, wuhan 430074 The center for Material Research and testing Wuhan University of Technology Faculty of Earth Sciences China University of Geosciences

A supergene gold deposit is located at Shewushan, south Hubei, Central china. The Au mass fraction of the supergene deposits ranges from 1.0.10-6 to 19.5 10-6, with an average of about 2.2.10-6. Primary gold mineralization is closely associated with the well developed faults and fractures mainly on the crest of the reverse anticline with gold mass fraction exceeding1.0 X 10-6(average 0.6 X 10-6 ), the gold occurs as small Ag-bearing particles in association with illite and kaolinite, and partly incorporated within the lattice of pyrite. Fluid inclusion studies on the gold mineralization yield trapping temperatures and pressures from 110 to 2.0 and 410 105 to 460 105 pa, respectively. The salinities of mineralization fluids range from 2. 6 % to 8. 4 % w(NaCl, equivalent). Calculated (18O) values and measured (D) data of the hypogene fluids indicate a meteoric origin. These fluids underwent extreme 18 O enrichment by reacting with country carbonate rock. Supergene gold minerali- zation is confined largely to the lower portion at the weathered mantle; the gold occurs as small native gold particles accompanied by clay minerals, kaolinite and illite and Mn and Fe oxides. Geochemical investigation shows that Au, together with As and Sb, decreases progressively from the top of ore body to some 2.kilometers away and define a lateral dispersion halo. It is proposed that the gold is mobilized by surficial leaching and concentrated at the lower portion of the weathering profile, and thio-sulfate may play an active role in gold dissolution and re-precipitation.

关键词： gold deposit weathering inclusion temperature stable isotopes Shewushan.

The study of two-color excitation upconversion of Pr(0.5)Yb(3):ZBLAN

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Science china(Physics,Mechanics & Astronomy) 2006年第2期49卷 169-177页

作者： CHEN Xiaobo1 & SONG Zengfu2.1. Applied Optics Beijing Area Major Laboratory, Analysis and testing center, Beijing Normal {2., Beijing 100875, china 2. Peking {2., Physics School, Beijing 100871, china Applied Optics Beijing Area Major Laboratory Analysis and testing center Beijing Normal University Beijing China Physics School Peking University Beijing China

The excited state absorption upconversion of Pr(0.5)Yb(3):ZBLAN glass material, under two-color excitation of the 960 nm semiconductor laser and the Xe lamp light simultaneously, is reported in this article. It was found that the upconversion emission spectra of 480.1, 519.0, 601.9 and 631.8 nm coincide with the common emission spectra. Meanwhile, the upconversion-excitation spectrum has three obvious peaks under two-color excitation, and they respectively correspond to the 856.0 nm upconversion ex-citation transition [1G4(Pr3+)→1I6(Pr3+) and 1G4(Pr3+)→3P1(Pr3+)], the 789.0 nm upconver-sion excitation transition 1G4(Pr3+)→3P2.Pr3+), and the 803.7 nm upconversion excitation transition 3H6(Pr3+)→1D2.Pr3+). The upconversion excitation transition 1G4(Pr3+)→1I6(Pr3+) is strong because its oscillator strength f = 2..040×10?6 is large, which results in a large peak appearing in the upconversion excitation spectrum. That is just the new interesting two-color excitation upconversion luminescence phenomenon of Pr(0.5)Yb(3):ZBLAN induced by one laser and one continuous normal light simultaneously.

关键词： upconversion volumetric three-dimensional display two-color excitation.

First Preparation and Reactivity of γ-Oxo Vinyliminophosphorane

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Chinese Chemical Letters 1997年第4期8卷 289-290页

作者： Ming Wu DING Wen Fau HUNG Hai Yang TO(Institute of Organic Synthesis,Central china Normal university,{2., 430070)Tian Jie WU(center of Analysis and testing,Central china Normal university,{2.,430070) Institute of Organic Synthesis Central China Normal University Wuhan 430070 China center of Analysis and testing Central China Normal University Wuhan 430070 China

The γ-oxo vinyliminophosphorane 3 was prepared for the first time from the Staudinger reaction of vinyl azide 2.and triphenylphosphine. The reaedvity of 3 was studied

关键词： First Preparation and Reactivity of Oxo Vinyliminophosphorane

Statistical Inference for Simple Tree Order in the Means of Stochastic Order on Stratified Contingency Tables

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wuhan university Journal of Natural Sciences 2010年第2期15卷 93-98页

作者： YAN Guoyi1,2. CHEN Jingjing3 1.School of Mathematics and Statistics, wuhan university, wuhan 430072. Hubei, china 2. School of Sciences, wuhan Institute of Technology, wuhan 430074, Hubei, china 3. School of Sciences, wuhan university of Science and Technology, wuhan 430081, Hubei, china School of Mathematics and Statistics Wuhan University Wuhan China School of Sciences Wuhan Institute of Technology Wuhan China School of Sciences Wuhan University of Science and Technology Wuhan China

In this paper, we consider testing the hypothesis that all multinomial populations in the stratified contingency table are identically distributed against the alternative that all these popula- tions are in simple tree order. We provide an asymptotic represen- tation of the order-restricted maximum likelihood estimate of the unknown parameters. The resulting estimators are proven to be ~n-consistent and asymptotically normal under appropriate conditions. A chi-squared test method is used for this hypothesis test problem. A real data set is applied to illustrate our theoretical result.

关键词： simple tree order chi-squared test asymptotic representation asymptotic distribution

Determination of the Thermal Expansion Coefficient of Concrete at Early Ages by Using Temperature-stress testing Machine

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Journal of wuhan university of Technology(Materials Science) 2006年第4期21卷 146-149页

作者：霍凯成 Hubei Key Laboratory of Roadway Bridge & Structure Engineering Wuhan University of TechnologyWuhan 430070China

By using the uptodate temperatuer-stress testing machine, the thermal expansion coefficient of concrete at early ages was studied and indicative conclusions were achieved ： temperature rising due to hydration heat is not directly correlated with cracking, but the temperature and stress evolation process should be taken into consideration in the same time. Proper chemical admixtures and mineral cornpasitions can improve the mechanical properties of concrete such as thermal expansion coefficient, which is very indicative in practice.

关键词： concrete coefficient of thermal expansion temperature-stress test

^(13)C NMR spectra of tectonic coals and the effects of stress on structural components

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Science china Earth Sciences 2005年第9期48卷 1418-1437页

作者： JU Yiwen1,2. JIANG Bo1, HOU Quanlin2. WANG Guiliang1 & NI Shanqin2.1. College of Mineral Resource and geosciences, china {2. of Mining and Technology, Xuzhou 2.1008, china 2. Laboratory of Computational Geodynamics, College of geosciences, Graduate School of Chinese Academy of Sciences, Beijing 100049, china College of Mineral Resource and geosciences China University of Mining and Technology Xuzhou China Laboratory of Computational Geodynamics College of Geosciences Graduate School of Chinese Academy of Sciences Beijing China

High-resolution 13C Nuclear Magnetic Resonance (NMR) spectra of different kinds of tectonic coals were obtained using the NMR (CP/MAS+TOSS) method. On the basis of this, after simulation synthesis and division of spectra, the relative contents of carbon functional groups were calculated. Combined with results of Ro, max, XRD testing and element analysis, stress effects on the composition of macromolecular structures in tectonic coals were studied further. The results showed that Ro, max was not only the important index for describing coal rank, but was also effective for estimating the stress effect of tectonic coals. Under tectonic stress ac- tion, Ro, max was the most direct indicator of the coal structure and chemical components. Changes in the stacking Lc of the coal basic structure unit (BSU) and La/Lc parameters could distinguish the temperature and stress effects on metamorphic-deformed environments, and re- flected the degree of structural deformation. Therefore, on the whole, Lc and La/Lc can be used to index of the degree of structural deformation of tectonic coals. In different metamorphic and de- formed environments, different kinds of tectonic coals are formed under structural stress. The changes in characteristics of the macromolecular structure and chemical composition are such that as the increase in structural deformation becomes stronger, from the brittle deformation coal to ductile deformation coal, the ratio of width at the half height of the aromatic carbon and ali- phatic carbon peaks (Hfa/Hfal ) was increased. As carbon aromaticity was raised further, carbon aliphaticity reduced obviously and different compositions of macromolecular structure appeared as a jump and wave pattern except for in wrinkle structure coal, which might result chiefly from stress effects on the macromolecular structure of different kinds of tectonic coals. The macro- moecular changes of wrinkle structure coal are reflected mainly on physical structure. In the metamorphi

关键词： tectonic coal, NMR, macromolecular structure, chemical component, stress effect.

Stodies on the Witting Reaction (Ⅹ Ⅹ Ⅻ) Phase Transfer Catalytic Bis-Witting Reaction of 1,2.and 1,3-Bisylide

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Chinese Chemical Letters 1997年第5期8卷 361-364页

作者： Wen Jing XIAO Zi Long TANG Ming Wu DING Wen Fang HUANG(Insititute of Organic Synthesis, Central china Normal university, {2.430070)Tian Jie WU(center of Analysis and testing, Central china Normal university, {2.430070) Insititute of Organic Synthesis Central China Normal University Wuhan 430070 China center of Analysis and testing Central China Normal University Wuhan 430070 China

The phase transfer catalytic (PTC) bis-Wittig reaction between substitutedbenzaldehyde and 1,2. and 1,3-bisylides in the presence of K2.o3 was discussed.

关键词： HNMR MS Phase Transfer Catalytic Bis-Witting Reaction of 1,2.and 1,3-Bisylide Stodies on the Witting Reaction

INFLUENCE　OF　ALLOYING　ELEMENTS（Nb，Mo，V）　ON　MICROSTRUCTURE　OF　Ti_3Al　BASE　ALLOYS

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Acta Metallurgica Sinica(English Letters) 1996年第2期9卷 85-88页

作者： SONG Dan DING Jinjun WANG Yandong(Analysis and testing center,Northeastern {2.,Shenyang 110006,china) Northeastern Univ Shenyang China

The microstructures of Ti-14Al-2.Nb and Ti-14Al-2.Nb-2.o-3.2.(wt%) alloys have been investikated by transmission electron microscopy(TEM).The phase constitution and the orientation relationship between α2.nd βwere identified by means of the selected area diffraction and the micro-diffraction *** show that,compared to Ti-14Al-2.Nb,the alloying elements Mo and V can greatly increase the fraction of β phase and improve significantly the microstructures of *** ordered B2.structure is also evident in the residual βgrains of the latter alloy.

关键词： microstructure alloying element Ti_3Al base alloy TEM