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Timing and geochemical characters of the Sanchazi magmatic arc in Mianlüe tectonic zone,South Qinling

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Science china Earth Sciences 2004年第4期47卷 317-328页

作者： LI Shuguang1, HOU Zhenhui1, YANG Yongcheng2, SUN Weidong1,1), ZHANG Guowei3, & LI Qiuli1 1. School of Earth and Space Sciences,university of Science and Technology of china ,Hefei 230026,china 2. Regional Geological Survey Team of Shaanxi Province,xianyang 712000, china 3. department of geology, northwest university,xi抋n 710069, china School of Earth and Space Sciences University of Science and Technology of China Hefei China Regional Geological Survey Team of Shaanxi Province Xianyang China Max-Planck-Institut f. Chemie Mainz Germany department of geology Northwest University Xi’an China

The Sanchazi mafic-ultramafic complex in Mianlüe tectonic zone,South Qinling can be subdivided into two blocks,*** paleo-magmatic arc and Zhuangkegou paleo-oceanic crust fragment (ophiolite).The Sanchazi paleo-magmatic arc is mainly composed of ande-site,basaltic and basalt-andesitic gabbro(or diorite),andesitic dyke,plagiogranite and minor ul-tramafric rocks,which have typical geochemical features of island arc volcanic rocks,such as high field strength element(***,Ti)depletions and lower Cr,Ni *** Light rare earth element (LREE) and K enrichments of these rocks and zircon xenocrystals of 900 Ma from plagiogranite suggest that this magmatic arc was developed on the South active continental margin of the South Qinling *** U-Pb age of (300±61) Ma for zircons from plagiogranite in-dicates that the Mianlüe paleo-oceanic crust was probably subducted underneath the South Qinling micro-continent in *** is consistent with the formation time (309Ma) of the Huwan eclogite originating form oceanic subduction in Dabie Mountains,suggesting that the Mianlüe paleo-ocean probably extended eastward to the Dabie Mountains in *** high-Mg adakitic rocks in Sanchazi paleo-magmatic arc suggest thet the subducted oceanic crust was relatively young (<25Ma) and hot.

关键词： Qinling orogen, magmatic arc, U-Pb zircon age, ophiolite complex.

Discovery of bipinnatifid fronds of Protoblechnum contractum(Gu et Zhi)

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Chinese Science Bulletin 1999年第4期44卷 381-383页

作者： SUN Bainian and SHEN Guanglong department of geology, Lanzhou university, Lanzhou 730000, china department of geology, northwest university, xi’an 710069, china department of geology Lanzhou University Lanzhou China department of geology Northwest University Xi’an China

IN Permian floras of china, a dispute over the relationship among the Protoblechnum and other similar plants such as Compsopteris, Glenopteris and Supaia has been existing for a long time, and moreover it has not been completely solved up to now. Halle placed a few simple pinnate fronds from the Shihhotze Formation in the genus Protoblechnum and named them Protoblechnum Wongii Halle 70 years ago when he was studying the fossil plants from the Late Palaeozoic strata in Shanxi, china. He did not think forked or unforked fronds as an important dividing genus condition in discussing the distinction among Protoblechnum and other relative fossils. Zalessky alSO found some specimens similar to Chinese Protoblechnum while he studied the Permian fossil plants from Russia. However, he did not approve of

关键词： very over Discovery of bipinnatifid fronds of Protoblechnum contractum Gu et Zhi

Invariant sets and solutions to the generalized thin film equation

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Science china Mathematics 2007年第6期50卷 875-886页

作者： Chang-zheng QU & Chun-rong ZHU Center for Nonlinear Studies, northwest university, xi’an 710069, china department of Mathematics, northwest university, xi’an 710069, china department of Mathematics, Anhui Normal university, Wuhu 241000, china Center for Nonlinear Studies Northwest University Xi’an China department of Mathematics Northwest University Xi’an China department of Mathematics Anhui Normal University Wuhu China

The invariant sets and the solutions of the 1+2-dimensional generalized thin film equation are discussed. It is shown that there exists a class of solutions to the equations, which are invariant with respect to the set $$E_0 = \{ u:u_x = v_x F(u),u_y = v_y F(u)\} ,$$ where v is a smooth function of variables x, y and F is a smooth function of u. This extends the results of Galaktionov (2001) and for the 1+1-dimensional nonlinear evolution equations.

关键词： thin film equation invariant set invariant solution rotation group scaling group 35K55 35K40 82C26

TECTONIC SIGNIFICANCE OF THE WEST KUNLUN FOLD-THRUST-BELT AND THE TARIM SOUTHWEST DEPRESSION

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地学前缘 2000年第S1期7卷 84-86页

作者： Luo Jinhai (department of geology, northwest university, xi′an 710069,china)

The evolution of the Tarim southwest depression lying at the piedmont of the West Kunlun orogen differs completely from the evolution of the main part of Tarim basin after Later Palaeozoic because the former strongly subsides many times.. Subsidence is related closely to the West Kunlun fold thrust\|belt, thus the evolution of the Depression and the fold\|thrust\|belt reflects clearly the formation and evolution of the West Kunlun and even the Tibet.1 Evolution of the West Kunlun fold\|thrust\|belt\;Thrusting of the fold\|thrust\|belt can be classified into three stages:(1) Devonian thrusting:This is the oldest thrusting distinguished in the northern margin of the West Kunlun while the Silurian—Devonian thrusting was discriminated a few years ago by seismic data in the northern part of the East Kunlun. The Devonian thrusting is proved by the Upper Devonian dynamometamorphic rocks outcropping at the core of the anticline in the Sangzhu lying at the fold\|thrust\|belt. The rocks consist of slightly metamorphic clastic rock and have always been regarded as the Mid\|Proterozoic strata. But they are actually Upper Devonian strata according to the amount of perfect plant fossils that we found recently in the metamorphic rock, and they are overburdened `with an angular unconformity by another reliable Upper\|Devonian conglomerate in the core of the Aqike anticline. A possible explanation for this and its limited lined distribution parallel to the West Kunlun orogen is that they are subjected to metamorphism during the Later Devonian thrusting.

关键词： evolution West Kunlun fold\|thrust\|belt Tarim southw est depression correspondence

Northernmost paleo-tethyan oceanic basin in Tibet:Geo-chronological evidence from ^(40)Ar/^(39)Ar age dating of Dur'ngoi ophiolite

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Chinese Science Bulletin 2001年第14期46卷 1203-1205页

作者： CHEN Liang, SUN Yong, PEI xianzhi, GAO Ming, FENG Tao, ZHANG Zhongqing & CHEN Wen1. Laboratory of Continental Dynamics, northwest university, xi’an 710069, china 2. department of geology, northwest university, xi’an, 710069, china 3. Institute of geology, Chinese Academy of Geological Sciences, Beijing, 100037, china Laboratory of Continental Dynamics Northwest University Xi’an China department of geology Northwest University Xi’an China Institute of geology Chinese Academy of Geological Sciences Beijing China

Whole rock 40Ar/39Ar age dating has been conducted on a basalt sample from Dur’ngoi ophiolite, Qinghai Province, which was reported to be the northernmost pa-leo-tethyan oceanic basin in Tibet. A high temperature pla-teau age (345.3±7.9 Ma) with an isochorn age (336.6±7.1 Ma) has been obtained, representing the eruption time of oceanic crust Considering related geological settings, the new age provides constraints on the northernmost pa-leo-tethyan suture zone in Tibet and the tectonic evolution of Paleo-tethys in Northeast Tibet and adjacent areas.

关键词： Dur’ngoi ophlolite 40Ar -39Ar age Paleo-tethys.

A paleontological perspective of vertebrate origin

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Chinese Science Bulletin 2003年第8期48卷 725-735页

作者： SHU Degan Early Life Institute & department of geology, northwest university, xi抋n, 710069, china School of Earth Sciences and Resources, china university of Geosciences, Beijing, 100083, china (e-mail: elidgshu@ ***) Early Life Institute Department of Geology Northwest University Xi'an 710069 China School of Earth Sciences and Resources China University of Geosciences Beijing 100083 China

The Early Cambrian Haikouichthys and Haikouella have been claimed to be related to contribute in an important way to our understanding of vertebrate origin, but there have been heated debates about how exactly they are to be interpreted. New discoveries of numerous speci-mens of Haikouichthys not only confirm the identity of pre-viously described structures such as the dorsal and the ven-tral fins, and chevron-shaped myomeres, but also reveal many new important characteristics, including sensory or-gans of the head (e.g. large eyes), and a prominent notochord with differentiated vertebral elements. This 揻irst fish?ap-pears, however, to retain primitive reproductive features of acraniates, suggesting that it is a stem-group craniates. A new order (Myllokunmingiida) and a new family (Myllo-kunmingiidae) are erected, and a new species, Zhongjianich-thys rostratus (gen. et sp. nov.), is described herein. Over 1400 newly-discovered specimens of Haikouella provide a wealth of anatomical information on this organism. It differs from chordates in many organs and organ systems, including the skin, muscles, respiratory, circulatory and nervous sys-tems. In contrast, its body-design resembles that of vetuli-colians, and the presence of a 搕ransitional?nervous system with both dorsal and ventral nerve cords suggests an affinity with living hemichordates. On the basis of these and other recent findings of fossil deuterostomes, a five-step hypothesis for vertebrate origin is proposed, intended to bridge the long- standing gap between protostomes and vertebrates. Four of the five steps accord with established ideas current in modern evolutionary zoology. Evidence for the first step is obtainable only from fossils, and specifically from fossils found from South china, hence the crucial importance of S. china sites for our understanding of early vertebrate origins and evolution. Accordingly, South china is suggested as the oldest-known birthplace of the whole vertebrates.

关键词：脊椎动物动物起源寒武纪中国南部地区

On the Mean Value Formula of Dedekind Sums

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Acta Mathematica Sinica,English Series 1999年第2期15卷 245-254页

作者： xiali He Wenpeng Zhang, department of Mathematics, northwest university, xi’an 710069, P. R. china department of Mathematics Northwest University Xi’an P. R. China

The main purpose of this paper is to use the mean value theorem of the Dirichlet L-function to study the distribution property of Dedekind sums, and to give a sharper mean value formula.

关键词： Dedekind sums Distribution of the mean value Asymptotic formula

PRELIMINARY GROUP CLASSIFICATION OF EQUATION v_t=f(x, v_x)v_(xx)+g(x, v_x)

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Acta Mathematica Scientia 1997年第3期17卷 255-261页

作者：屈长征 department of Mathematics Northwest University Xi'an 710069 China

Using the method of preliminary group classification introduced by Ibragimov et al[***.32,2988(1991)], we give a classification of equations vt= f(x, vx)vxx+g(x, vx) which admitting an extension by one of the principal Lie algebra of the equation. The result of this paper is a table of nonequivalent equations possessing an additional symmetry.

关键词： SYMMETRY CLASSES COEFFICIENT

A modified multi-reference second order perturbation theory

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中国科学：化学英文版 2010年第4期53卷 933-939页

作者： LI AnYang1, HAN Huixian2, SUO BingBing3, WANG YuBin3 & WEN ZhenYi3 1Institute of Computational Chemistry, Chongqing university of Post and Telecommunications, Chongqing 400065, china 2department of Physics, northwest university, xi’ an 710069, china 3Institute of Modern Physics, northwest university, xi’ an 710069, china Institute of Computational Chemistry Chongqing University of Post and Telecommunications Chongqing China department of Physics Northwest University Xi’ an China Institute of Modern Physics Northwest University Xi’ an China

A new scheme with extended model space is proposed to improve the calculation of multi-reference second order perturbation theory (MRPT2). The new scheme preserves the concise code structure of the original program, and avoids intruder states in constructions of the potential energy surface, which is confirmed by a series of comparable calculations. The new MRPT2 program is an available tool for the research of molecular excited states and electronic spectrum.

关键词： perturbation theory multi-reference intruder state