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| 1 | On adjacent-vertex-distinguishing total coloring of graphs显示文摘In this paper, we present a new concept of the adjacent-vertex-distinguishing total coloring of graphs (briefly, AVDTC of graphs) and, meanwhile, have obtained the adjacent-vertex-distinguishing total chromatic number of some graphs such as cycle, complete graph, complete bipartite graph, fan, wheel and tree. | ZHANG Zhongfu, CHEN Xiang’en, LI Jingwen, YAO Bing, LU Xinzhong & WANG Jianfang College of Mathematics and Information Science, Northwest Normal University, Lanzhou 730070, China Department of Computer, Lanzhou Normal College, Lanzhou 730070, China Institute of Applied Mathematics, Lanzhou Jiaotong University, Lanzhou 730070, China College of Information and Electrical Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China Institute of Applied Mathematics, Chinese Academy of Sciences, Beijing 100080, China | 2005 | Science China Mathematics2005,48,3: | 173 |
| 2 | Discovery of ultrahigh-pressure magnesite-bearing garnet lherzolite (>3.8 GPa) in the Altyn Tagh, Northwest China显示文摘Magnesite-bearing garnet Iherzolite from the Altyn Tagh, associated with garnet pyroxenite, and garnet-bearing felsic gneiss, crops out as lenses in Proterozoic gneiss about 100 km east of the Jianggelasayi River. The garnet Iherzolite, together with the eclogite in western Jianggelasayi, composes a high-pressure to ultrahigh-pressure metamorphic belt in the southern margin of the Altyn Tagh. Parageneses of minerals from magnesite-bearing garnet Iherzolite indicate that the rock evolved a multi-stage metamorphism. The peak-stage metamorphism produces an assemblage of Grt+Ol+Opx+Cpx±Mgs, in which A12O3 content of Opxis very low (0.30-0.66wt%). The calculated P-T condition of the peak stage is 3.8-5.lGPa and 880-970°C, some exsolution rods of clinopyroxene and rutile occur in the Grt and magnesite is rimed by dolomite and orthopyroxene, all implying that the peak stage was a UHP metamorphic process. Together with regional geological studies, isotopic dating and the discovery of coesite inclusions in | LIU Liang, SUN Yong, XIAO Peixi, CHE Zicheng, LUO Jinhai, CHEN Danling, WANG Yan, ZHANG Anda, CHEN Liang & WANG YongheKey Laboratory of Continental Dynamics of the Ministry of Education, Northwest University, Xi’an 710069, China The Northwest Institute of | 2002 | Chinese Science Bulletin2002,47,11: | 69 |
| 3 | D(β)-vertex-distinguishing total coloring of graphs显示文摘A new concept of the D(β)-vertex-distinguishing total coloring of graphs, i.e., the proper total coloring such that any two vertices whose distance is not larger than β have different color sets, where the color set of a vertex is the set composed of all colors of the vertex and the edges incident to it, is proposed in this paper. The D(2)-vertex-distinguishing total colorings of some special graphs are discussed, meanwhile, a conjecture and an open problem are presented. | ZHANG Zhongfu,LI Jingwen,CHEN Xiang’en,YAO Bing, WANG Wenjie & QIU Pengxiang Institute of Applied Mathematic, Lanzhou Jiaotong University, Lanzhou 730070, China College of Mathematics and Information Science, Northwest Normal University, Lanzhou 730070, China College of Information and Electrical Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China | 2006 | Science China Mathematics2006,49,10: | 54 |
| 4 | Mianlüe tectonic zone and Mianlüe suture zone on southern margin of Qinling-Dabie orogenic belt显示文摘The Mianle tectonic zone (Mianle zone), an ancient suture zone in addition to the Shangdan suture in the Qinling-Dabie orogenic belt, marks an important tectonic division geo-logically separating north from south and connecting east with west in China continent. To de-termine present structural geometry and kinematics in the Mianle tectonic zone and to recon-struct the formation and evolution history involving plate subduction and collision in the Qinling-Dabie orogenic belt, through a multidisciplinary study, are significant for exploring the mountain-building orogenesis of the central orogenic system and the entire process of the major Chinese continental amalgamation during the Indosinian. | ZHANG Guowei1, DONG Yunpeng1, LAI Shaocong1, GUO Anlin1, MENG Qingren2, LIU Shaofeng3, CHENG Shunyou1, YAO Anping1, ZHANG Zongqing4, PEI Xianzhi5 & LI Sanzhong6 1. Department of Geology, Northwest University, Xian 710069, China 2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100101, China 3. Earth Science and Resource Faculty, China University of Geosciences, Beijing 100083, China 4. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China 5. Changan University, Xian 710054, China 6. Qingdao University of Oceanography, Qingdao 266003, China | 2004 | Science China Earth Sciences2004,47,4: | 57 |
| 5 | Ultrahigh pressure (>7 GPa) gneissic K-feldspar (-bearing) garnet clinopyroxenite in the Altyn Tagh, NW China: Evi- dence from clinopyroxene exsolution in garnet显示文摘The exsolution of clinopyroxene and rutile in coarse-grain garnet is found in the gneissic K-feldspar(-bearing) garnet clinopyroxenite from Yinggelisayi in the Altyn Tagh, NW China. The maximum content of the exsolved clinopyroxene in the garnet is up to >5% by volume. The reconstructed precursor garnet (Grt1) before exsolution has a maximum Si content of 3.061 per formula uint, being of supersilicic or majoritic garnet. The peak-stage metamorphic pressure of >7 GPa is estimated using the geobarometer for volume percentage of exsolved pyroxene in garnet and the Si-(Al+Cr) geobarometer for majoritic garnet, and the temperature of about 1000℃ using the ternary alkali-feldspar geothermometer and the experimental data of ilmen- ite-magnetite solid solution. The protoliths of the rocks are intra-plate basic and intermediate ig- neous rocks, of which the geochemical features indicate that they are probably the products of the evolution of basic magma deriving from the continental lithosphere mantle. The rocks are in outcrops associated with ultrahigh pressure garnet-bearing lherzolite and ultrahigh pressure garnet granitoid gneiss. All of these data suggest that the ultrahigh pressure metamorphic rocks in the Altyn Tagh are the products of deep-subduction of the continental crust, and such deep- subduction probably reaches to >200 km in depth. This may provide new evidence for further discussion of the dynamic mechanism of the formation and evolvement of the Altyn Tagh and the other collision orogenic belts in western China. | LIU Liang1,3, CHEN Danling1, ZHANG Anda1, SUN Yong1, WANG Yan1, YANG Jiaxi1,2 & LUO Jinhai1 1. Key Laboratory of Continental Dynamics of the Ministry of Education of China, Northwest University, Xi’an 710069, China 2. College of Earth Science and Land Resources, Chang’an University, Xi’an 710054, China 3. The Laboratory of Orogen and Basin of the Ministry of Education, Peking University, Beijing 100871, China | 2005 | Science China Earth Sciences2005,48,7: | 38 |
| 6 | Changes in plant biomass and species composition of alpine Kobresia meadows along altitudinal gradient on the Qinghai-Tibetan Plateau显示文摘Alpine Kobresia meadows are major vegetation types on the Qinghai-Tibetan Plateau. There is growing concern over their relationships among biodiversity, productivity and environments. Despite the im-portance of species composition, species richness, the type of different growth forms, and plant bio-mass structure for Kobresia meadow ecosystems, few studies have been focused on the relationship between biomass and environmental gradient in the Kobresia meadow plant communities, particularly in relation to soil moisture and edaphic gradients. We measured the plant species composition, her-baceous litter, aboveground and belowground biomass in three Kobresia meadow plant communities in Haibei Alpine Meadow Ecosystem Research Station from 2001 to 2004. Community differences in plant species composition were reflected in biomass distribution. The total biomass showed a de-crease from 13196.96±719.69 g/m2 in the sedge-dominated K. tibetica swamp to 2869.58±147.52 g/m2 in the forb and sedge dominated K. pygmaea meadow, and to 2153.08±141.95 g/m2 in the forbs and grasses dominated K. humilis along with the increase of altitude. The vertical distribution of below-ground biomass is distinct in the three meadow communities, and the belowground biomass at the depth of 0-10 cm in K. tibetica swamp meadow was significantly higher than that in K. humilis and K. pygmaea meadows (P<0.01). The herbaceous litter in K. tibetica swamp was significantly higher than those in K. pygnaeca and K. humilis meadows. The effects of plant litter are enhanced when ground water and soil moisture levels are raised. The relative importance of litter and vegetation may vary with soil water availability. In the K. tibetica swamp, total biomass was negatively correlated to species richness (P<0.05); aboveground biomass was positively correlated to soil organic matter, soil moisture, and plant cover (P<0.05); belowground biomass was positively correlated with soil moisture (P<0.05). However, in the K. pygnaeca and K. humilis meadow communities, aboveground biomass was posi-tively correlated to soil organic matter and soil total nitrogen (P<0.05). This suggests that the distribu-tion of biomass coincided with soil moisture and edaphic gradient in alpine meadows. | WANG ChangTing1,3, CAO GuangMin1, WANG QiLan1, JING ZengChun1, DING LuMing1 & LONG RuiJun2 1 Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810001, China 2 College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730070, China 3 Graduate University of the Chinese Academy of Sciences, Beijing 100039, China | 2008 | Science China(Life Sciences)2008,51,1: | 31 |
| 7 | Ultra-high pressure metamorphism of granitic gneiss in the Yinggelisayi area, Altun Mountains, NW China显示文摘 | LIU Liang, SUN Yong, LUO Jinhai, WANG Yan, CHEN Danling & ZHANG Anda The Key Laboratory of Continental Dynamics, Ministry of Education,Department of Geology, Northwest University, Xi抋n 710069, China | 2004 | Science China Earth Sciences2004,47,4: | 27 |
| 8 | Geochemistry and regional distribution of ophiolites and associated volcanics in Mianlüe suture, Qinling-Dabie Mountains显示文摘Systematic studies of the ophiolites and associated volcanics stretching more than 1500 km from the Derni-Nanping-Pipasi-Kangxian area in the west to the Qingshuihe area of the south Dabie Mountains in the east indicate the existence of a suture zone (the Mianl黣 suture) and a vanished paleo-ocean basin (the Mianl黣 paleo-ocean basin) in the region. From west to east, ophiolitic mlange associations distribute discontinuously along the suture. Rock assem-blages include ophiolite, island arc and oceanic island rock series. The Mianl黣 paleo-ocean basin experienced its major formation and expending episode during the Carboniferous-Permian period. The finding of the suture zone and the paleo-ocean basin is tectonically significant in timing the collision between the North China-Qinling and Yangtze blocks and determining the formation and evolution of the Qinling orogenic belt. | LAI Shaocong, ZHANG Guowei, DONG Yunpeng, PEI Xianzhi & CHEN Liang Key Laboratory of Continental Dynamics, Ministry of Education and Department of Geology, Northwest University, Xian 710069, China | 2004 | Science China Earth Sciences2004,47,4: | 25 |
| 9 | Dissimilatory Fe(Ⅲ) reduction characteristics of paddy soil extract cultures treated with glucose or fatty acids显示文摘Dissimilatory Fe(Ⅲ) reduction is a universal process with irreplaceable biological and environmental importance in anoxic environments. Our knowledge about Fe(Ⅲ) reduction predominantly comes from pure cultures of dissimilatory Fe(Ⅲ) reducing bacteria (DFRB). The objective of this study was to compare the effects of glucose and a selection of short organic acids (citrate, succinate, pyruvate, propionate, acetate, and formate) on Fe(Ⅲ) reduction via the anaerobic culture of three paddy soil solutions with Fe(OH)3 as the sole electron acceptor. The results showed significant differences in Fe(Ⅲ) reduction among the three paddy soil solutions and substrate types. Bacteria from the Sichuan paddy soil responded quickly to substrate supply and showed higher Fe(Ⅲ) reducing activity than the other two soil types. Bacteria in the Jiangxi paddy soil culture solution could not use propionate as a source of electrons for Fe(Ⅲ) reduction. Similarly, bacteria in the Jilin paddy soil culture could not use succinate effectively. Pyruvate was readily used by cultures from all three paddy soil solutions, thus indicating that there were some similarities in substrate utilization by bacteria for Fe(Ⅲ) reduction. The use of glucose and citrate as substrate for dissimilatory Fe(Ⅲ) reduction indicates important ecological implications for this type of anoxic respiration. | HE Jiangzhou1,2, QU Dong1, 1. College of Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China.2. Xinjiang Production & Construction Corps Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin, Tarim University, Alar, Xinjiang Uygur Autonomous Region, Xinjiang 843300, China | 2008 | Journal of Environmental Sciences2008,20,9: | 24 |
| 10 | Northernmost paleo-tethyan oceanic basin in Tibet:Geo-chronological evidence from ^(40)Ar/^(39)Ar age dating of Dur'ngoi ophiolite显示文摘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. | 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 | 2001 | Chinese Science Bulletin2001,46,14: | 24 |
| 11 | Hydrogen peroxide-induced changes in intracellular pH of guard cells precede stomatal closure显示文摘Epidermal bioassay demonstrated that benzylamine, a membrane-permeable weak base, can mimick hydrogen peroxide (H2O2) to induce stomatal closure, and butyric acid, a membrane-permeable weak acid, can partly abolish the H2O2-induced stomatal closure. Confocal pH mapping with the probe 5-(and-6)- carboxy seminaphthorhodafluor- 1 - acetoxymethylester (SNARF-1-AM) revealed that H2O2 leads to rapid changes in cytoplasmic and vacuolar pH in guard cells of Viola faba L, i. e. alkalinization of cytoplasmic areas occur red in parallel with a decrease of the vacuolar pH, and that butyric acid pretreatment can abolish alkalinization of cytoplasmic areas and acidification of vacuolar areas of guard cells challenged with H2O2. These results imply that the alkalinization of cytoplasm via efflux of cytosol protons into the vacuole in guard cells challenged with H2O2 is important at an early stage in the signal cascade leading to stomatal closure. | ZHANG XIAO, FA CAI DONG, JUN FENG GAO, CHUN PENG SONG (Department of Biology, Henan University, Kaifeng 475001, China) (College of Life Sciences, Northwest Sci-Tech University of Agriculture and Forestry, Yangling 712100, China) | 2001 | Cell Research2001,11,1: | 24 |
| 12 | Geochemistry and U-Pb zircon geochronology of Late-Mesozoic lavas from Xishan,Beijing显示文摘Zircon U-Pb dating by both SHRIMP and LA-ICP-MS and geochemical study of the Tiaojishan Formation and the Donglintai Formation from Xishan, Beijing, reveal that ages of upper lavas of Tiaojishan Formation and Middle of Donglintai Formation are 137.1±4.5 Ma(2σ ) and 130-134 Ma, respectively. The fomer is slightly older than the latter and the age difference between these two formations is less than 5 Ma. These lines of evidence prove that the two volcanoes erupted within a short time. The age of the Tiaojishan Formation from Xishan, Beijing is distinctively different from that of the Chende Basin. This indicated that the ages of Tiaojishan lavas varied in different regions. The Tiaojishan Formation consists of typical adakite (SiO2=56%, Na2O = 3.99-6.17, Na2O/K2O = 2.2-3.1, Sr = 680-1074×10?6, Y = 13.2-16.3×10?6, Yb = 1.13-1.52×10?6, Sr/Y = 43-66), high-Mg adakite and high-Mg andesite (Mg# = 54-55). Features of continental crust of adakite from the Tiao-jishan Formation and its syngeneric middle silicic vocanic rocks, such as typical Nd-Ta negative ab-normality and Pb possive abnormality, indicate that these lavas are originated from partial melts of continental crust. These results suggest that the adakite from the Tiaojishan Formation of Xishan, Beijing derived from thickened eclogitic lower crust and lithosphere beneath the North China craton at mesozoic that was foundered into the aesthenosphere, and subsequenctly partially melted and in-teracted with mantle olivine during melts upward migration. The age of lavas from the Tiaojishan Formation restrained the foundation which should last at least until 137 Ma. Lavas of the Donglintai Formation are rhyolith and andesite with normal Mg# and thus they did not interact with the mantle. These lavas represent remobilized melts of lower crust material caused by mantle aesthenosphere upwelling migration induced by foundation. | YUAN Honglin1, LIU Xiaoming1, LIU Yongsheng2, GAO Shan1,2 & LING Wenli2 1. Key Laboratory of Continental Dynamics, Northwest University, Xi’an 710069, China 2. Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China | 2006 | Science China Earth Sciences2006,49,1: | 22 |
| 13 | Chinese Overseas investment Calls for Perfection of Overseas Investment Insurance显示文摘Overseas investment insurance is a non-profitable insur- ance provided by the government of a state for her enterprises which have invested in the developing countries or areas against political risks.Such a gov- ernmental guarantee system was first established in the United States in the middle of last century.Nowadays most developed countries and some of the developing countries have followed American practices and set up similar systems to encourage their enterprises to make investment in developing areas which are often regarded to be more easily to have political risks.In | Liu Yajun,associateprofessor,tutor of postgraduate,vice dean of the School of International Law of Northwest University of Political Science and Law.His main research orientation includes international trade law and international investment law. | 2008 | China's Foreign Trade2008,,8: | 22 |
| 14 | Geochemical Features of Ophiolite in Mianxian Lueyang Suture Zone,Qinling Orogenic Belt显示文摘GeochemicalFeaturesofOphioliteinMianxianLueyangSutureZone,QinlingOrogenicBeltLaiShaocong;ZhangGuowei(DepartmentofGeology,Nort... | Lai Shaocong Zhang Guowei(Department of Geology, Northwest University, Xi’an 710069) | 1996 | Journal of Earth Science1996,15,2: | 22 |
| 15 | Geochemistry of the high-Mg andesites at Zhangwu, western Liaoning: Implication for delamination of newly formed lower crust显示文摘Ten volcanic samples at Zhangwu,western Liaoning Province,North China were selected for a sys-tematic geochemical,mineralogical and geochronological study,which provides an opportunity to ex-plore the interaction between the continental crust and mantle beneath the north margin of the North China craton.Except one basalt sample(SiO2= 50.23%),the other nine samples are andesitic with SiO2 contents ranging from 53% to 59%.They have relatively high MgO(3.4%―6.1%,Mg#=50―64) and Ni and Cr contents(Ni 27×10?6―197×10?6,Cr 51×10?6―478×10?6).Other geochemical characteristics of Zhangwu high-Mg andesites(HMAs) include strong fractionation of light rare earth elements(LREE) from heavy rare earth elements(HREE),and Sr from Y,with La/Yb greater than 15,and high Sr/Y(34― 115).Zircons of andesite YX270 yield three age groups with no Precambrian age,which precludes ori-gin of the Zhangwu HMAs from the partial melting of the Precambrian crust.The oldest age group peaking at 253 Ma is interpreted to represent the collision of the Siberia block and the North China block,resulting in formation of the Central Asian orogenic belt by closure of the Mongol-Okhotsk Ocean.The intermediate age group corresponds to the basalt underplating which caused the wide-spread coeval granitoids in the North China craton with a peak 206Pb/238U age of 172 Ma.The youngest age group gives a 206Pb/238U age of 126±2 Ma,which is interpreted as the eruption age of the Zhangwu HMAs.The high 87Sr/86Sri(126 Ma)>0.706 and low εNd(t)= ?6.36―?13.99 of the Zhangwu HMAs are distinct from slab melts.The common presence of reversely zoned clinopyroxene phenocrysts in the Zhangwu HMAs argues against the origin of the Zhangwu HMAs either from melting of the water saturated mantle or melting of the lower crust.In light of the evidence mentioned above,the envisaged scenario for the formation of the Zhangwu HMAs is related to the basaltic underplating at the base of the crust,which led to the thickening of the lower crust and formation of lower crustal eclogite,followed by foundering of the eclogitic lower crust into the asthenosphere.The foundered eclogite then melted and the resul-tant melts interacted with surrounding peridotite during their upward transport,which finally produced the high-Mg andesites.This well explains the high-Mg adakitic characters and absence of ancient in-herited zircon in the Zhangwu lavas. | HUANG Hua1,GAO Shan1,2,HU ZhaoChu1,LIU XiaoMing2 & YUAN HongLing2 1 State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China 2 State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi’an 710069,China | 2007 | Science China Earth Sciences2007,50,12: | 20 |
| 16 | Formation of the Permian basalts and implications of geochemical tracing for paleo-tectonic setting and regional tectonic background in the Turpan-Hami and Santanghu basins,Xinjiang显示文摘The Turpan-Hami and Santanghu basins are the late Paleozoic-Mesozoic-Cenozoic re-worked intracontinental basins that superposed on the folded basement of the Paleozoic orogenic belt. 40Ar/39Ar geochronological study of the basalts developed in the basins reveals that the formation period is Permain (293—266 Ma). From geochemical comparison of the basalts, the Santanghu basalts exhibit a strong depletion in Nb and Ta, and a selective enrichment in HFSE, reflecting that the source region is influenced by the subducted components related to subduction of the ancient oceanic crust and characterized with “lagged arc volcanic rocks”. In contrast, the Turpan-Hami basalts show a slight depletion in Nb and Ta, high Th/Ta ratio, similar to the basalts formed in an intracontinental ex-tensional zone or in an initial rift. Combined with the formation period of the ophiolite and ophiolite mélange zones and regional magmatic activities occurring on the post-orogenic extensional back-ground in northern Xinjiang, it can be inferred from these geochemical characteristics that the tectonic background for forming the Turpan-Hami and Santanghu basins is closely related to the regional ex-tension after the continent-continent collisional orogeny. The basalts of the two basins came from different sources on the post-orogenic extensional background of the similar basin-forming dynamics. Although the settings are all intracontinental rift, the source for the Santanghu basalts is obviously subjected to the metasomatism of the subducted components, implying the existence of the previous subduction. | ZHOU Dingwu1,2, LIU Yiqun1,2, XING Xiujuan1, HAO Jianrong1, DONG Yunpeng1 & OUYANG Zhengjian1 1. Key Laboratory of Continental Dynamics, Ministry of Education, Northwest University Department of Geology, Northwest University, Xi’an 710069, China 2. Geoinformation Science & Engineering College, SDUST, Qingdao 266510, China | 2006 | Science China Earth Sciences2006,49,6: | 20 |
| 17 | Geochemistry of high-Mg andesites from the early Cretaceous Yixian Formation, western Liaoning: Implications for lower crustal delamination and Sr/Y variations显示文摘85 volcanic rocks of the Yixian Formation from the Sihetun type section were collected and analyzed for geochemical and isotopic compositions. Major element compositions indicate that the Sihetun volcanic rocks are high magnesium andesites with some basalts occurring at the bottom of section. The Sihetun high magnesium andesites (SiO2 = 52.82―59.31wt%, Al2O3 = 14.15―16.35wt%) show many characteristics of adakites such as depletion in heavy rare-earth elements (HREE; Yb = 1.03―1.88 μg/g) and Y(12―20 μg/g) and high Sr (620―1323 μg/g) and Sr/Y(32―88), with high LaN/YbN ratio (10―25). They share similar major and trace element characteristics to volcanic rocks from the Xinglonggou Formation except their lower Nd isotope ratios (143Nd/144Nd (130Ma) = 0.5118―0.5119, ε Nd (130Ma) = ?11.6―?13.8, 87Sr/86Sr (130 Ma) = 0.7058―0.7064. They were in- terpreted in a way that eclogite that formed at the base of thickened Archean lower crust of the North China craton foundered into the convecting mantle and subsequently melted and interacted with peridotite. However, compared to the Xinglonggou volcanic rocks, the source of the Sihetun magma contained more ancient continental crustal material in order to explain its evolved Nd isotopes. The age of the Sihetun Formation was 120 to 130 Ma, and this indicates that delamination lasted to the early Cretaceous period. The Sr contents and Sr/Y ratios of the Sihetun high-Mg andesites show sig- nificant negative correlations with SiO2 for samples with SiO2 > 56%. These suggest that the Sr and Sr/Y values were reduced due to fractional crystallization of plagioclase. Accordingly, the effect of crystallization on volcanic Sr and Sr/Y ratio has to be taken into account. | WANG Xiaorui1, GAO Shan1,2, LIU Xiaoming1, YUAN Honglin1, HU Zhaochu1, ZHANG Hong1,3 & WANG Xuance4 1. State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi`an 710069, China 2. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China 3. Shenyang Institute of Geology and Mineral Resources, Shenyang 110032, China 4. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China | 2006 | Science China Earth Sciences2006,49,9: | 19 |
| 18 | Effect of areca on contraction of colonic muscle strips in rats显示文摘AIM: To investigate the effects of areca on the contractileactivity of isolated colonic muscle strips in rats andmechanism involved.METHODS: Each strip (LMPC, longitudinal muscle ofproximal colon; CMPC, circular muscle of proximal colon;LMDC, longitudinal muscle of distal colon; CMlC, circularmuscle of distal colon. ) was suspended in a tissue chambercontaining 5 mL Krebs solution (37 ℃), bubbledcontinuously with 950 mL@ L-1 O2 and 50 mL@ L-1 CO2 . Themean contractile amplitude (A), the resting tension (T),and the contractile frequency (F) were simultaneouslyrecorded on recorders.RESULTS: Arsca dose dependently increased the meancontractile amplitude, the resting tension of proximal anddistal colonic smooth muscle strips in rats ( P < 0.05). Italso partly increased the contractile frequency of colonicsmooth muscle strips in rats ( P < 0.05). The effects werepartly inhibited by atropine (the resting tension of LMPCdecreased from 0. 44 ± 0. 12 to 0. 17 ± 0.03; the restingtension of LMDC decreased from 0.71 ± 0.14 to 0.03 ± 0.01;the mean contractile amplitude of LMPC increased from -45.8 ± 7.2 to -30.5 ± 2.9; the motility index of CMDC decreasedfrom 86.6± 17.3 to 32.8 ± 9.3; P< 0.05 vs areca), but theeffects were not inhibited by hexamethonium (P> 0.05).CONCLUSION: Areca stimulated the motility of isolatedcolonic smooth muscle strips in rats. The stimulation ofareca might be relevant with M reoeptor partly. | Dong-Ping Xie Lian-Bi Chen,Department of Physiology,Medical College,Shandong University,Jinan 250012,Shandong Province,China Wei Li Song-Yi Qu Tian-Zhen Zheng,Department of Physiology,Lanzhou Medical College,Lanzhou 730000,Gansu Province,China Ying-Li Yang,Northwest Normal University,Lanzhou 730070,Gansu Province,China Yong-Hui Ding Yu-Ling Wei,Drug Control Institute of Gansu Province,Lanzhou 730000,Gansu Province,China | 2002 | World Journal of Gastroenterology2002,8,2: | 18 |
| 19 | Timing and geochemical characters of the Sanchazi magmatic arc in Mianlüe tectonic zone,South Qinling显示文摘The Sanchazi mafic-ultramafic complex in Mianlüe tectonic zone,South Qinling can be subdivided into two blocks,I.e.Sanchazi 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(e.g.Nb,Ti)depletions and lower Cr,Ni contents.The 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 micro-continent.The 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 Carboniferous.This 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 Carboniferous.The high-Mg adakitic rocks in Sanchazi paleo-magmatic arc suggest thet the subducted oceanic crust was relatively young (<25Ma) and hot. | 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 | 2004 | Science China Earth Sciences2004,47,4: | 16 |
| 20 | Carbon isotope ratios of C_(4) plants in loess areas of North China显示文摘Carbon isotope ratios (δ 13C) of 89 C4 plant samples were determined from the loess area in North China. δ 13C values vary between –10.5‰ and –14.6‰ with a mean of –12.6‰. Along a pre-cipitation gradient from the semi-moist area to the semiarid area, then to the arid area, the δ 13C val-ues of C4 plants show a slight decreasing trend. The δ 13C values of C4 plants in the dry season are found lower than those in the wet season. These trends are opposite to those observed for C3 spe-cies. | WANG Guoan1,2,3, HAN Jiamao 2, ZHOU Liping3, XIONG Xiaogang4, TAN Ming2, WU Zhenhai5 & PENG Jun6 1. Department of Plant Nutrition, China Agricultural University, Beijing 100094, China 2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 3. College of Environmental Sciences, MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China 4. Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China 5. Northwest Sci-Tech University of Agriculture and Forestry, Yangling 712100, China 6. Network Center, China Agricultural University, Beijing 100094, China | 2006 | Science China Earth Sciences2006,49,1: | 16 |