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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 4.0070, {2. 2. Testing Center, china university of geosciences, wuhan 4.0074, {2. 1. College of Resources and Environment Huazhong Agricultural University 430070 Wuhan China 2. Testing Center China University of Geosciences 430074 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.

Deformation in the Three Gorges Reservoir after the first impoundment determined by GPS measurements

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Progress in Natural Science:Materials International 2005年第6期15卷 515-522页

作者： DU Ruilin 1,2., QIAO Xuejun 1,2.*, WANG Qi 1,2., XING Canfei 1,2.and YOU Xinzhao 1,3 (1. Institute of Seismology, CEA, {4. 4.0071, china 2. Laboratory of Crustal Movement and {2. Observation, {4. 4.0071, china 3. Center for Analysis and Prediction, CEA, Beijing 100036, china) Institute of Seismology CEA Wuhan 430071 China Laboratory of Crustal Movement and earth Observation Wuhan 430071 China Center for Analysis and Prediction CEA Beijing 100036 China

A 6-year long GPS observation (1998—2.03) indicates that crustal deformation in the Three Gorges area is less active at a marginally measurable rate of 0—5 mm/a relative to stable South china block. However, the impounding water in June 2.03 has induced transient displacement at the Three Gorges dam and the emerging reservoir. GPS measurements after the first stage of water filling of the reservoir demonstrate that vertical subsidence close by Yangtze River is about 10—4. mm, and the horizontal displacement is less than 5—10 mm. The maximum subsidence induced by the impoundment is located in the segment of the reservoir from Maoping to Xiangxi. The water loading-induced deformation diminishes rapidly with the distance from banks of the reservoir. The overall pattern of transient deformation is consistent with the simulation result of Farrell, and is attributed to the elastic response of upper lithosphere crust to overlying water reservoir.

关键词： Three Gorges GPS impoundment deformation.

Commission Strategy of the Auction House

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wuhan university Journal of Natural Sciences 2006年第3期11卷 507-510页

作者： WANG Yan~ 1,2.1. College of Economics, Fudan university, Shanghai 2.04.3, china 2. School of Mathematics and Statistics, {2. university , {2. 4.0072. Hubei, china College of Economics Fudan University 200433 Shanghai China School of Mathematics Statistics Wuhan University 430072 Wuhan Hubei China

In a SIPV model, when the commission proportion is not certain, but related with bargain price, generally, it is a linear function of the bargain price, this paper gives bidders＇ equilibrium bidding strategies in the first-and secondprice auctions. We find that the equilibrium strategies in second-price auction are dominant strategies. For seller or auction house, whether the fixed proportion or the unfixed proportion is good is not only related with constant item and the linear coefficient of the linear function, the size of the fixed commission proportion, but also related with the value of the item auctioned. So, in the practical auctions, the seller and the auction house negotiated with each other to decide the commission rules for their own advantage.

关键词： auction commission proportion Bayesian equilibrium bidding strategy

Petrogenesis and dating of the Kangding complex,Sichuan Province

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Science china earth Sciences 2005年第5期48卷 622-634页

作者： CHEN Yuelong 1 , LUO Zhaohua 1 , ZHAO Junxiang, LI Zhihong, ZHANG Hongfei & SONG Biao 3 1. Faculty of earth Sciences and Natural Resources, china university of geosciences, Beijing 100083, {2. 2. Faculty of earth Sciences, china university of geosciences, wuhan 4.0074, {2. 3. Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, {2. 1. Faculty of earth Sciences and Natural Resources China University of Geosciences 100083 Beijing China 2. Faculty of earth Sciences China University of Geosciences 430074 Wuhan China 3. Beijing SHRIMP Center Institute of Geology Chinese Academy of Geological Sciences 100037 Beijing China

An analysis of major and trace element geochemistry and SHRIMP U-Pb zircon dating of mafic, intermediate, and felsic rocks from the Mianning metamorphic complex of Si- chuan Province was conducted. One of our conclusions is that a majority of the zircons crystal- lized between 72. and 773 Ma in a magmatic regime. The complexes contain early to late Pa- leo-proterozoic relict zircons from ancient continental crust. The oldest age, 2.68 Ma, may rep- resent the basement of the Yangtze block. Overgrowth zircon rims and palingenetic zircons have been observed and dated, and are believed to have formed after crystallization, during Paleozoic and Mesozoic metamorphic-anatexis. We also conclude that depletion of Nb, Ta, HREE, in a spider-diagram normalized to primitive mantle and calc-alkaline association, implies that they formed in island-arc or under-plating settings.

关键词： Kangding complex, zircons, SHRIMP, tectonic setting.

The crustal structure under Sanjiang and its dynamic implications:Revealed by seismic reflection/refraction profile between Zhefang and Binchuan,Yunnan

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Science china earth Sciences 2005年第9期48卷 1329-1336页

作者： ZHANG Zhongjie1, BAI Zhiming1, WANG Chunyong2. TENG Jiwen1, Lü Qingtian3, LI Jiliang1, LIU Yifeng1 & LIU Zhenkuan4.1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 10002., china 2. Institute of Geophysics, china Seismological Bureau, Beijing 100085, china 3. Institute of Deposition Resource, Chinese Academy of geosciences, Beijing 100037, china 4. School of Exploration and Information, china university of geosciences, Beijing 100083, china 1. Institute of Geology and Geophysics Chinese Academy of Sciences 100029 Beijing China 2. Institute of Geophysics China Seismological Bureau 100085 Beijing China 3. Institute of Deposition Resource Chinese Academy of Geosciences 100037 Beijing China 4. School of Exploration and Information China University of Geosciences 100083 Beijing China

The fault belts in Sanjiang mainly include Jinshajiang-Honghe fault, Lancangjiang fault and Nujiang fault (called Sanjiang faults) in western Yunnan Province, china. By interpreting the wide-angle seismic reflection/refraction profile between Zhefang and Binchuan, which crosses Tengchong and Baoshan blocks in Dianxi (western Yunnan) tectonic zone, we recon- struct the crustal structure with seismic traveltime tomography for crustal P-wave velocity and the seismic scattering image for crustal seismic reflection structure. In this paper, we firstly present the crustal structure images of P-wave velocity and seismic reflection under the wide-angle seismic profile. These results demonstrate that, the crustal velocity structure and seismic reflec- tion structure along the profile can be divided into 3 segments, and there is an obvious difference of crustal structure among the eastern, the western and the middle segment. Generally, crustal P-wave velocities in the Baoshan segment are 0.1―0.2.km/s slower and seismic reflection am- plitudes from Moho discontinuity are stronger than the other 2.segments. In the studied area, crustal thickness is about 4. km, and shows the thickening tendency from west to east along the profile. Additionally, it can be seen that there is one strong-amplitude seismic reflection event as bright points at the depths of 8―10 km, along the segment of 80―115 km of the profile (south- ward of Tengchong); and seismic reflection wave-field from Moho discontinuity varies obviously along the lateral direction. Finally, we make some discussions on the crustal thickening pattern in the Sanjiang fault belt, structural environment of earthquake development and the contact rela- tionship between the Tengchong block, Banshan block and Luxi trough.

关键词： Sanjiang area wide-angle seismic profile crustal structure.

Electronic Structure of Doped Trans-Polyacetylene

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wuhan university Journal of Natural Sciences 2002年第1期7卷 51-53页

作者： Ren Da-zhi 1,2. Zhuang Wei 2. Wang Jun 2.1. wuhan {4. Journals Press,wuhan 4.0072.Hubei,china 2. School of Physics and Technology, wuhan {4., wuhan 4.0072.Hubei,china wuhan university Journals Press Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) wuhan university School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) wuhan university School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

The behavior of electronic structures of doped trans-polyacetylene is revealed by a simple method. (C2.H2.)+n is used to simulate p-type doped trans-polyacetylene at various doping concentrations. The electronic structure is calculated, by CNDO/2.method. These calculations show that at low doping level, the decrease of electronic energy compensates the increase of elastic energy, thus the bond alternation exists, and the charge carriers are solitons. When doping level is high, the increase of elastic energy is larger than the decrease, of electronic energy, the bond alternation disappears, solitons no longer exist, and polyacetylene is in a metalic state.

关键词： trans polyacetylene CNDO/2 electronic structure doped

The GPS-gravimetry boundary value problem

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Science china earth Sciences 2005年第3期48卷 398-405页

作者： YU Jinhai1,2.& ZHANG Chuanding2.1. Institute of Geodesy and Geophysics of Chinese Academy of Sciences, wuhan 4.0077, china 2. Zhengzhou Information Engineering {2., Zhengzhou 4.0052. china 1. Institute of Geodesy and Geophysics of Chinese Academy of Sciences 430077 Wuhan China 2. Zhengzhou Information Engineering university 450052 Zhengzhou China

How to determine the earth’s external gravity field with the accuracy of O(T2. by making use of GPS data and gravity values measured on the earth’s surface is dealt with in this paper. There are two main steps: to extend these measured values on the earth’s surface onto the reference ellipsoid at first and then to seek for the integral solution of the external Neumann problem outside the ellipsoid. In addition, the corresponding judging criteria of accuracy to solve the GPS-gravity boundary value problem are established. The integral solution given in the paper not only contains all frequency-spectral information of the gravity field with the accuracy of O(T 2., but is also easily computed. In fact, the solution has great significance for both theory and prac- tice.

关键词： Neumann boundary value problem, integral solution, gravity disturbance.

Paleoceanographic evolution recorded in the northern South china Sea since 4.Ma

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Science china earth Sciences 2005年第12期48卷 2166-2173页

作者： HUANG Baoqi1,2. JIAN Zhimin2.& WANG Pinxian2.1. School of earth and Space Sciences, Peking {4., Beijing 100871, {2. 2. Laboratory of Marine Geology, Tongji {4., Shanghai 2.0092. {2. 1. School of earth and Space Sciences Peking University 100871 Beijing China 2. Laboratory of Marine Geology Tongji University 200092 Shanghai China

Upper water structure over the last 4.million years in the northern South china Sea (SCS) was reconstructed by sea surface temperature (SST) and primary productivity estimated by changes in the abundance of planktonic foraminifer, planktonic foraminifer transfer function, and the accumulation rate of benthic foraminifera. Results of SST and primary productivity show that SST gradually decreased since 4.Ma, but differential seasonal temperature and primary productivity increased in steps mainly at about 3.1, 2.7, 2.1, 1.6, 0.9 and 0.5 Ma. Comparison with tectonics and orbital variations indicates that phased rising of the Tibet since 3.6 Ma, closing of Panama and Indonesian seaways, and orbital changes were responsible for the changes of upper water structure in the SCS, respectively.

关键词： northern South china Sea, upper water structure, Late Pliocene, planktonic foraminifer, ODP 114..

A Principal Theorem of Normal Discretization Schemes for Operator Equations of the First Kind

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wuhan university Journal of Natural Sciences 2001年第4期6卷 767-768页

作者： Du Nai lin 1, Wang Hannah 2.1.School of Mathematics and Statistics, wuhan university, wuhan 4.0072. china 2. School of Foreign Languages and Literature,wuhan university,wuhan 4.0072.china wuhan university School of Mathematics and Statistics Wuhan China (GRID:grid.49470.3e) (ISNI:***) wuhan university School of Foreign Languages and Literature Wuhan China (GRID:grid.49470.3e) (ISNI:***)

The authors announce a newly-proved theorem of theirs. This theorem is of principal significance to numerical computation of operator equations of the first kind.

关键词： operator equation of the first kind normal discretization scheme pure pseudoinverse