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Locating seismic scatterers at the base of the mantle beneath eastern Tibet with PKIKP precursors

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Chinese science Bulletin 2010年第24期55卷 723-729页

作者： SHEN XuZhang 1,2,3 & ZHOU HuiLan 1 1 Laboratory of Computational Geodynamics,Graduate University of the Chinese Academy of sciences,Beijing 100049,china 2 lanzhou institute of Seismology,china earthquake administration,lanzhou 73.000,china 3 lanzhou base of institute of earthquake Prediction,china earthquake administration,lanzhou 73.000,china Laboratory of Computational Geodynamics Graduate University of the Chinese Academy of Sciences Beijing China lanzhou institute of Seismology China Earthquake Administration Lanzhou China lanzhou base of institute of earthquake Prediction China Earthquake Administration Lanzhou China

Clear PKIKP precursors were observed from the lanzhou CTBTO seismic *** measured their incident angles,arriving azimuths and differential travel times with respect to the PKIKP arrivals using array analysis *** measurements allowed us to locate the scatterers that generated the observed *** found that the scatterers are located in the lowermost mantle beneath eastern Tibet,which is featured by a high-velocity anomaly based on previous tomographic *** high velocity anomaly was interpreted as the slab remnants of the ancient Tethys *** thus speculate that the observed scatterers are either related or induced by the subducted slab.

关键词：地震前兆西藏东部下地幔散射定位地震台阵入射角度旅行时间

Textual research of Wudu earthquake in 186 B.C. in Gansu Province, china and discussion on its causative structure

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Acta Seismologica Sinica(English Edition) 2007年第6期20卷 696-707页

作者：袁道阳雷中生何文贵熊振葛伟鹏刘兴旺刘百篪 lanzhou institute of Seismology China Earthquake Administration earthquake administration of Jiangsu Province

On the basis of the textual research on the historical earthquake data and the field investigation of Wudu earthquake occurred in 186 B.C., we suggest that the earthquake parameters drawn from the present earthquake catalogs are not definite and amendments should be made. The heavily-damaged area of this earthquake should be located between Jugan township of Wudu County and Pingding township of Zhouqu County. Its epicenter should be in the vicinity of Lianghekou in Wudu County with a magnitude of about 7-7 1/4 and an intensity of about IX-X. The major axis direction of the heavily-damaged area should be in the WNW direction that is approximately consistent with the strike of the middle-east segment of Diebu-Bailongjiang active fault zone, and the origin time should match up to that of the latest paleoearthquake event [before （83±46） B.C.] obtained by the trench investigation. Certain seismic rupture evidences are still preserved on this fault segment. Therefore, we propose on the basis of comprehensive analysis that the causative structure of the M 7-7 1/4 Wudu earthquake in 186 B.C. should be in the middle-east segment of Diebu-Bailongjiang active fault zone.

关键词： Wudu earthquake in 186 B.C. textual research of historical earthquake causative structure Diebn-Bailongjiang fault zone

Velocity structure and active fault of Yanyuan-Mabian seismic zone―The result of high-resolution seismic refraction experiment

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science china Earth sciences 2008年第9期51卷 1284-1296页

作者： WANG FuYun1↑, DUAN YongHong1, YANG ZhuoXin1, ZHANG ChengKe1, ZHAO JinRen1, ZHANG JianShi1, ZHANG XianKang1, LIU QiYuan2, ZHU AiLan2, XU XiWei2 & LIU BaoFeng1 1 Geophysical Exploration Center, china earthquake administration, Zhengzhou 450002, china 2 institute of Geology, china earthquake administration, Beijing 100029, china Geophysical Exploration Center China Earthquake Administration Zhengzhou China institute of Geology China Earthquake Administration Beijing China

The authors processed the seismic refraction Pg-wave travel time data with finite difference tomography method and revealed velocity structure of the upper crust on active block boundaries and deep features of the active faults in western Sichuan Province. The following are the results of our investigation. The upper crust of Yanyuan basin and the Houlong Mountains consists of the superficial low-velocity layer and the deep uniform high-velocity layer, and between the two layers, there is a distinct, and gently west-dipping structural plane. Between model coordinates 180-240 km, P-wave velocity distribution features steeply inclined strip-like structure with strongly non-uniform high and low velocities alternately. Xichang Mesozoic basin between 240 and 300 km consists of a thick low-velocity upper layer and a high-velocity lower layer, where lateral and vertical velocity variations are very strong and the interface between the two layers fluctuates a lot. The Daliang Mountains to the east of the 300 km coordinate is a non-uniform high-velocity zone, with a superficial velocity of approximately 5 km/s. From 130 to 150 km and from 280 to 310 km, there are extremely distinct deep anomalous high-velocity bodies, which are supposed to be related with Permian magmatic activity. The Yanyuan nappe structure is composed of the superficial low-velocity nappe, the gently west-dipping detachment surface and the deep high-velocity basement, with Jinhe-Qinghe fault zone as the nappe front. Mopanshan fault is a west-dipping low-velocity zone, which extends to the top surface of the basement. Anninghe fault and Zemuhe fault are east-dipping, tabular-like, and low-velocity zones, which extend deep into the base-ment. At a great depth, Daliangshan fault separates into two segments, which are represented by drastic variation of velocity structures in a narrow strip: the west segment dips westward and the east segment dips eastward, both stretching into the basement. The east margin f

关键词： western Sichuan high-resolution seismic refraction active fault velocity structure of the upper crust

Acid-base behavior of cryptand 1, 4, 7, 10, 13, 16, 21, 24-octaaza-bicyclo [8, 8, 8] hexacosan-3, 8, 12, 17, 20, 25-hexone and complex formation

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Rare Metals 2002年第1期21卷 12-19页

作者： MO Zunli, CHEN Hong and GAO Jinzhang institute of Chemistry, Northwest Normal University, lanzhou 730070, china institute of Chemistry Northwest Normal University Lanzhou 730070

The bicyclic cryptand 1,4,7, 10,13,16,21, 24-octaaza-bigcyclo [8, 8,8] hexacosan-3, 8, 12, 17, 20, 25-hex-one (COBH) bearing diaminoethane groups along the eight-atom bridges was synthesized. The structure consists of discrete neutral macrobicyclic units; the two cycles share the two tertiary amine nitrogen atoms, which exhibit an endo-cndo conformation. Three identical branches formed by 1, 2-diaminoethane link the two tertiary amine groups. The protonation reactions of cryptand (COBH) and its complex formation with copper (II) were investigated by potentiometry in water and in a DMSO/water (80:20 in mass ratio) mixture as solvents. The cryptand acts as a his-base through its two N-bridgehead and exhibits a strong cooperativity that favors the first protonation and makes the second one difficult (△pK= 5.0). An inward rotation of the amide groups to form hydrogen bonds accounts for this cooperativity. The interaction of COBH with copper (II) leads to several binuclear complex proton contents.

关键词： COBH(cryptand 1,4,7, 10, 13, 16, 21, 24-octaaza-bigcyclo hexacosan -3, 8, 12, 17,20,25 - hex-one) macrobicyclic acid-base behavior complex formation proton contents

Are nuclear loci ideal for barcoding plants? A case study of genetic delimitation of two sister species using multiple loci and multiple intraspecific individuals

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Journal of Systematics and Evolution 2011年第3期49卷 182-188页

作者： 1Qian WANG 1,2Qiu-Shi YU 1Jian-Quan LIU* 1(Molecular Ecology Group,Key Laboratory of Arid and Grassland Ecology,College of Life sciences,lanzhou University,lanzhou 73.000,china) 2(State Key Laboratory Breeding base of Desertification and Aeolian Sand Disaster Combating,Gansu Desert Control Research institute,lanzhou 730070,china) (Molecular Ecology Group Key Laboratory of Arid and Grassland Ecology College of Life Sciences Lanzhou University Lanzhou 730000 China) (State Key Laboratory Breeding base of Desertification and Aeolian Sand Disaster Combating Gansu Desert Control Research Institute Lanzhou 730070 China)

Considerable debate remains as to which DNA region should be used to barcode *** different chloroplast(cp) DNA regions(rbcL,matK,and trnH-psbA) and nuclear ribosomal internal transcribed regions(ITS) have been suggested as suitable barcodes in ***,low-copy nuclear loci were also suggested to be potentially ideal barcode *** aim of the present study was to test the effectiveness of these proposed DNA fragments and five additional low-copy loci(CHS,DET1,COP1,PGIC1,and RPS2;comprising both coding and non-coding regions) in barcoding closely related *** examined the divergences within and between two species of Pugionium(Brassicaceae).We failed to find any interspecific variation from three cpDNA fragments with which to discriminate the two ***,a single base mutation in the internal transcribed spacer(ITS) could discriminate between the two species *** found more variations among all individuals of the two species using each of the other five low-copy nuclear ***,only alleles from one locus(DET1) of the five low-copy loci related to ?owering regulations was able to distinguish the sampled individuals into two *** failed to amplify the corresponding fragments out of Brassicaceae using the designed DET1 *** further discussed the discrimination power of different loci due to incomplete lineage sorting,gene ?ow,and species-specific *** results highlight the possibility of using the nuclear ITS as a core or complementary fragment to barcode recent diverged species.

关键词： chloroplast DNA DNA barcoding internal transcribed spacer(ITS) low-copy nuclear loci Pugionium.

Impact of land-use change on hydrological processes in the Maying River basin, china

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science china Earth sciences 2006年第10期49卷 1098-1110页

作者： WANG Genxu1,3, ZHANG Yu2, LIU Guimin2 & CHEN Lin3 1. institute of Mountain Hazards and Environment, Chinese Academy of sciences, Chengdu 610041, china 2. Cold and Arid Regions Environmental and Engineering Research institute, Chinese Academy of sciences, lanzhou 73.000, china 3. Resource and Environment School, lanzhou University, lanzhou 73.000, china institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu China Resource and Environment School Lanzhou University Lanzhou China Cold and Arid Regions Environmental and Engineering Research institute Chinese Academy of Sciences Lanzhou China

Since the 1960s, dramatic changes have taken place in land-use patterns characterized by the persistent expansion of cultivated land and a continuous decrease in natural woodland and grassland in the arid inland river basins of china. It is very important to assess the effects of such land-use changes on the hydrological processes so vital for water resource management and sustainable development on the catchment scale. The Maying River catchment, a typical arid inland watershed located in the middle of the Hexi Corridor in northwest china, was the site chosen to investigate the hydrological responses to land-use changes. The annual runoff, base flow, maximum peak flow, and typical seasonal runoff in both spring and autumn flood periods were selected as the variables in the hydrological processes. Statistical-trend analysis and curvilinear regression were utilized to detect the trends in hydrological variables while eliminating the climatic influence. The relationship between cultivated land-use and hydrological variables was analyzed based on four periods of land-use variation data collected since 1965. A runoff model was established composed of two factors, i.e., cultivated land use and precipitation. The impact of land use changes, especially in the large ar- eas of upstream woodland and grassland turned into cultivated lands since 1967, has resulted in a mean annual runoff decrease of 28.12%, a base flow decline of 35.32%, a drop in the maximum peak discharge of 35.77%, and mean discharge decreases in spring and autumn of 36.05% and 24.87% respectively, of which the contribution of cultivated land expansion to the influence of annual runoff amounts to 77%-80%, with the contribution to the influence of spring discharge being 73%-81%, and that to the influence of base flow reaching 62%-65%. Thus, a rational regulation policy of land use patterns is vitally important to the sustainable use of water resources and the proper development of the entire catchment.

关键词： land-use change, arid inland river catchment, hydrological process, impact, Maying River.

Geophysical survey on the tectonic and sediment distribution of Qinghai Lake basin

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science china Earth sciences 2006年第8期49卷 851-861页

作者： AN Zhisheng1, WANG Ping2, SHEN Ji3, ZHANG Yixiang2, ZHANG Peizhen4, WANG Sumin3, LI Xiaoqiang1, SUN Qianli1, SONG Yougui1, AI Li1, ZHANG Yechun2, JIANG Shaoren2, LIU Xingqi3 & WANG Yong31. institute of Earth Environment, Chinese Academy of sciences (CAS), Xi’an 710075, china 2. South china Sea institute of Oceanology, CAS, Guangzhou 510301, china 3. Nanjing institute of Geography and Limnology, CAS, Nanjing 210008, china 4. institute of Geology, china earthquake administration, Beijing 100029, china institute of Earth Environment Chinese Academy of Sciences (CAS) Xi’an China South china Sea institute of Oceanology CAS Guangzhou China Nanjing institute of Geography and Limnology CAS Nanjing China institute of Geology China Earthquake Administration Beijing China

The intensive geophysical survey of Qinghai Lake reveals the buried depth of lake sediments and their distribution features. The result indicates that there are three important inter- phases of Qinghai Lake sediments: T1 is the rife interphase of the lake, above which sediments are spread all over the lake basin with roughly the same thickness; T5 is the interphase from which the neotectonic sedimentary cycle begins, and its above sedimentary environment is relatively stable; Tg is the base of the lake basin. Five west-northwest (WNW) fault belts defined the tectonic structure of Qinghai Lake basin: the central hunch around Haixin Shan with two subbasins both in its north and south. The thickness of the lake sediments varies at different places, the thickest sediments are found within the two subbasins. According to the depth that the Sparker System can reach, sediment in the northern subbasin is deeper than 560 m, while sediment in the southern subbasin is deeper than 700 m. The correlation between the seismic sequence stratigraph and the lithology of onshore core shows that Qinghai Lake sediments consist of muddy silt, clay silt, silty clay, gravel silty clay, etc.

关键词： sediment, geophysical survey, Qinghai Lake.

Short cycle structures for graphs on surfaces and an open problem of Mohar and Thomassen

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science china Mathematics 2006年第2期49卷 212-224页

作者： REN Han & DENG Mo Department of Mathematics, East china Normal University, Shanghai 200062, china College of Mathematics & Information science, Northwest Normal University, lanzhou 730070, china Department of Mathematics East China Normal University Shanghai China College of Mathematics & Information science Northwest Normal University Lanzhou China

In this paper we investigate cycle base structures of a (weighted) graph and show that much information of short cycles is contained in an MCB (i.e., minimum cycle base). After setting up a Hall type theorem for base-transformation, we give a sufficient and necessary condition for a cycle base to be an MCB. Furthermore, we show that the structure of MCB in a (weighted)graph is unique. The property is also true for those having a longest length (although much work has been down in evaluating MCB, little is known for those having a longest length). We use those methods to find out some unknown properties for short cycles sharing particular properties in (unweighted) graphs. As applications, we determine the structures of short cycles in an embedded graph and show that there exist polynomially bounded algorithms in finding a shortest contractible cycle and a shortest two-sided cycle provided such cycles exist. Those answer an open problem of B. Mohar and C. Thomassen.

关键词： cycle base facial cycle graph embedding.

Multifield coupling model and its applications for pile foundation in permafrost

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science china Earth sciences 2005年第7期48卷 968-977页

作者： WU Yaping1,2, ZHU Yuanlin2, GUO Chunxiang1, SU Qiang1 & MA Wei2 1. School of Civil Engineering, lanzhou Jiaotong University, lanzhou 730070, china 2. State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research institute, Chinese Academy of sciences, lanzhou 73.000, china School of Civil Engineering Lanzhou Jiaotong University Lanzhou 730070 China State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

Importing the interface element which links the frozen soil base with concrete piles and considering the couplings of stress field, temperature field and moisture field, this paper es- tablishes the nonlinear visco-elastic plastic finite element model of pile-soil. For a practical bridge structure the stress field and displacement field of single pile in freezing process are calculated. This paper emphatically studies the process of the tangential frost heave stress field, freezing stress field and displacement field varying with time, and ulteriorly studies time variation process of single pile carrying capacity in freezing process.

关键词： permafrost pile foundation freezing process multifield coupling analysis model.