维普中文期刊产品整合服务
103篇 您的检索式:作者名="XI 3"
    题名 作者 年代 出处 被引量
1Association of H.pylori infection with gastric carcinoma:a Meta analysis显示文摘AIM: To follow the principles of evidence based medicine to reach the integrated results of these studies.METHODS: Twenty-one papers of case-control studies were selected, including 11 on gastric cancer, 7 on precancerous lesion of stomach and 3 on lymphoma of stomach: Meta analysis was used to sum up the odds ratios (OR) of these studies.RESULTS: H. Pylori vsgastric cancer (intestinal and diffuse type): the odds ratio from the fixed effect model is 3.0016(95% Cl 2.4197-3.7234, P < 0.001 ). H. Pylori vs precancerous lesion of stomach: a random effect model was used to calculate the summary odds ratio and its value is 2.5635 (95% Cl: 1.8477-3.5566, P < 0.01). H. Pylori vs lymphoma of stomach: though the quantity of literature is too small to make Meta analysis, the data of these 3 studies show that lymphoma of stomach is highly associated with H. Pylori infections.CONCLUSION: Since it had been revealed that H. Pylori infection pre-exists in gastric carcinoma and precancerous lesions, the results of Meta analysis present a strong evidence to support the conclusion that H. Pylori infection is a risk factor for gastric carcinoma.Fu-Bo Xue~1 Yong-Yong Xu~1 Yi Wan~1 Bo-Rong Pan~2 Jun Ren~2 Dai-Ming Fan~3 1 Department of Health Statistics,Department of2 Oncology3 Gastroenterology of XiJing Hospital,the Fourth Military Medical University,Xi’an 710032,Shaanxi Province,China 2001World Journal of Gastroenterology2001,7,6:66
2Influence of the impounding process of the Three Gorges Reservoir up to water level 172.5m on water eutrophication in the Xiangxi Bay显示文摘The water level of the Three Gorges Reservoir(TGR) rose to 172.5 m in two stages from September to November,2008.The hydrodynamic parameters and water quality parameters(e.g.flow velocity,temperature,turbidity and nutrient content) had been continuously monitored to reveal the influence of the impounding process of the TGR on the water eutrophication in the Xiangxi Bay(XXB).The maximal daily rise of the water level of the TGR was about 2.38 m.The water exchange between the mainstream(the Changjiang River) and the XXB of the TGR was enhanced by density current,and its main characteristics were a density-stratified flow in different directions.The water exchange reduced the differences of the water quality parameters(for example,temperature,turbidity,nutrient level,pH,etc.) between the mainstream and the XXB during the impounding process.Meanwhile,the water stability index in the mainstream remained small but it was lowered in the XXB.The main causes included the dilution by water of lower concentration of the chlorophyll a(Chl.a) entering from the mainstream,the decline of the water stability,and the increase of suspended silt,which induced the Chl.a to decrease in the XXB during the impounding process.The grade of the water eutrophication changed from middle eutrophic level to mesotrophic state in the process.However,as available nutrients were imported into the XXB from the mainstream during the impounding process the risk of water eutrophication increases in the XXB in the future.YANG ZhengJian1,LIU DeFu1,JI DaoBin1,2 & XIAO ShangBin1,3 1 College of Civil & Hydroelectric Engineering,China Three Gorges University,Yichang 443002,China 2 School of Water Resources & Hydropower Engineering,Wuhan University,Wuhan 430072,China 3 Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710075,China 2010Science China(Technological Sciences)2010,53,4:58
3Ultrahigh 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 2005Science China Earth Sciences2005,48,7:38
4Grain-size features of a Miocene loess-soil sequence at Qinan: Implications on its origin显示文摘In this study, grain-size of 507 bulk samples from the QA-I Miocene loess-soil sequence at Qinan were analyzed, and the grain-size features are compared with those of typical Quaternary loess and soil samples, representative lacustrine and fluvial samples. The results indicate that the grain-size distribution pattern of the Miocene loess is essentially similar to that of Quaternary loess, but greatly differs from the lacustrine and fluvial sediments. Loess layers are regularly coarser than soil layers, indicating cyclical climate changes. Median grain-size along the 253.1 m sequence varies from 6 to 13 μm and the >63 μm fraction represents only 5.3% in maximum, 0.9% in average. Long-term grain-size variations are consistent with the loess accumulation rate at Qinan and with the eolian mass accumulation rate in the North Pacific. These features firmly indicate an eolian origin of the studied sequence, and also reveal a coeval changes between the long-term changes of eolian grain-size and continental aridity in the dust source regions.QIAO Yansong1,3, GUO Zhengtang2,1, HAO Qingzhen1, YIN Qiuzhen1, YUAN Baoyin1 & LIU Tungsheng1 1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China 2. Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710075, China 3. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China 2006Science China Earth Sciences2006,49,7:33
5Randomization of classical inference patterns and its application显示文摘By means of randomization, the concept of D-randomized truth degree of formulas in two-valued propositional logic is introduced, and it is proved that the set of values of D-randomized truth degree of formulas has no isolated point in [0,1]. The concepts of D-logic pseudo-metric and D-logic metric space are also introduced and it is proved that there is no isolated point in the space. The new built D-randomized concepts are extensions of the corresponding concepts in quantified logic. Moreover, it is proved that the basic logic connectives are continuous operators in D-logic metric space. Lastly, three different types of approximate reasoning patterns are proposed.WANG GuoJun1,2 & HUI XiaoJing1,31 Institute of Mathematics, Shaanxi Normal University, Xi’an 710062, China 2 Research Center for Science, Xi’an Jiaotong University, Xi’an 710049, China 3 College of Mathematics and Computer Science, Yan’an University, 716000, China 2007Science in China(Series F)2007,50,6:26
6Theory of truth degrees of propositions in the logic system Ln^*显示文摘By means of infinite product of uniformly distributed probability spaces of cardinal n the concept of truth degrees of propositions in the n-valued generalized Lu- kasiewicz propositional logic system L*n is introduced in the present paper. It is proved that the set consisting of truth degrees of all formulas is dense in [0,1], and a general expres- sion of truth degrees of formulas as well as a deduction rule of truth degrees is then ob- tained. Moreover, similarity degrees among formulas are proposed and a pseudo-metric is defined therefrom on the set of formulas, and hence a possible framework suitable for developing approximate reasoning theory in n-valued generalized Lukasiewicz proposi- tional logic is established.LI Jun1,2 & WANG Guojun1,3 1. Institute of Mathematics, Shaanxi Normal University, Xi’an 710062, China 2. School of Sciences, Lanzhou University of Technology, Lanzhou 730050, China 3. Research Center for Science, Xi’an Jiaotong University, Xi’an 710049, China 2006Science in China(Series F)2006,49,4:21
7Quantum secure direct communication with cluster states显示文摘A quantum secure direct communication protocol with cluster states is proposed.Compared with the deterministic secure quantum communication protocol with the cluster state proposed by Yuan and Song(Int.J.Quant.Inform.,2009,7:689),this protocol can achieve higher intrinsic efficiency by using two-step transmission.The implementation of this protocol is also discussed.CAO WeiFeng 1,YANG YuGuang 3,4,5* & WEN QiaoYan 2 1 College of Electric and Information Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,China 2 State Key Laboratory of Networking and Switching Technology,Beijing University of Posts and Telecommunications,Beijing 100876,China 3 College of Computer Science and Technology,Beijing University of Technology,Beijing 100124,China 4 State Key Laboratory of Integrated Services Network,Xidian University,Xi’an 710071,China 5 State key Laboratory of Information Security Gradute University of Chinese Academy of Sciences,Beijing 100049,China 2010Science China(Physics,Mechanics & Astronomy)2010,53,7:20
8Geochemistry 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 2006Science China Earth Sciences2006,49,9:19
9Symmetric-key cryptosystem with DNA technology显示文摘DNA cryptography is a new field which has emerged with progress in the research of DNA computing. In our study, a symmetric-key cryptosystem was designed by applying a modern DNA biotechnology, microarray, into cryptographic technologies. This is referred to as DNA symmetric-key cryptosystem (DNASC). In DNASC, both encryption and decryption keys are formed by DNA probes, while its ciphertext is embedded in a specially designed DNA chip (microarray). The security of this system is mainly rooted in difficult biology processes and problems, rather than conventional computing technology, thus it is unaffected by changes from the attack of the coming quantum computer. The encryption process is a fabrication of a specially designed DNA chip and the decryption process is the DNA hybridization. In DNASC, billions of DNA probes are hybridized and identified at the same time, thus the decryption process is conducted in a massive, parallel way. The great potential in vast parallelism computation and the extraordinary information density of DNA are displayed in DNASC to some degree.LU MingXin1,2*, LAI XueJia3*, XIAO GuoZhen4,2 & QIN Lei5 1 Department of Information Management, Nanjing University, Nanjing 210093, China 2 State Key Lab of Information Security, Institute of Software of Chinese Academy of Science, Beijing 100049, China 3 Department of Computer Science & Engineer, Shanghai Jiao Tong University, Shanghai 200030, China 4 State Key Lab of ISN, Xidian University, Xi’an 710071, China 5 Cancer Research Institute, Queen’s University, Kingston, Ontario, K7L3N6, Canada 2007Science in China(Series F)2007,50,3:14
10Modeling the climate effects of different subregional uplifts within the Himalaya-Tibetan Plateau on Asian summer monsoon evolution显示文摘Considering the different uplifting time of different subregions of the Himalaya-Tibetan Plateau(TP),a series of numerical simulations have been conducted with the Community Atmosphere Model(CAM4) developed at the National Center for Atmospheric Research to explore the effects of the phased tectonic uplift of the Himalaya-TP on the evolution of Asian summer monsoons.The results show that the uplifts of the Himalaya and northern TP significantly affect the evolutions of South Asian summer monsoon and northern East Asian summer monsoon respectively.That is,the tectonic uplift of the Himalaya intensifies the South Asian summer monsoon circulation and increases the precipitation in South Asia,whereas the uplift of the northern TP intensifies the northern East Asian summer monsoon circulation and increases the precipitation in northern East Asia.Compared with previous simulations,current comparative analyses of modeling results for different subregional uplifts within the Himalaya-TP help deepen our understanding of the evolutionary history of Asian monsoons.ZHANG Ran 1,JIANG DaBang 1,2,3,LIU XiaoDong 4 & TIAN ZhiPing 2,5 1 Climate Change Research Center,Chinese Academy of Sciences,Beijing 100029,China 2 Nansen-Zhu International Research Centre,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China 3 Key Laboratory of Regional Climate-Environment Research for Temperate East Asia,Chinese Academy of Sciences,Beijing 100029,China 4 State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710075,China 5 Graduate University of Chinese Academy of Sciences,Beijing 100049,China 2012Chinese Science Bulletin2012,57,35:14
11Petrogenesis of Indosinian volcanic rocks in Songpan-Garze fold belt of the northeastern Tibetan Plateau:New evidence for lithospheric delamination显示文摘In the Songpan-Garze fold belt of the northeastern Tibetan Plateau, an Indosinian lithospheric delamination model has been proposed, based on previous investigation of widespread granitoids. However, this model lacks comparable information from volcanism in the area. During the Indosinian delamination in the Songpan-Garze fold belt, whether partial melting of litho- spheric mantle taken place is debated. This paper reports U-Pb zircon LA-ICP-MS ages, geochemical and Sr-Nd-Hf isotopic compositions from the Aba and Wasai calc-alkaline volcanic rocks in the central Songpan-Garze fold belt. Obtained magma crystallization ages are 210±3 Ma for the Aba andesite and 205±1 Ma for the Wasai andesite. These are consistent with magma crystallization ages of the late Indosinian granitoids in the Songpan-Garze fold belt that formed in a post-collisional tectonic setting. The Aba and Wasai andesites have distinct geochemical singnatures. The former has higher Al2O3, K2O, Rb but lower Na2O, Ba and Sr contents, suggesting differences in their magmatic evolution. The Aba andesites have ISr values of 0.7070-0.7076 and εNd(t) values of -3.9 to -5.3, and the Wasai andesites have ISr values of 0.7075-0.7077 and εNd(t) values of -3.6 to -3.9. Zircons show εHf(t) values of -3.7 to 0.3 for the Aba andesites and -2.7 to 5.5 for the Wasai andesites. Geochemical and Sr-Nd-Hf isotopic compositions indicate that fractional crystallization and crustal assimilation processes are not key roles for their magma evolution, implying that their chemical compositions are those of primary melts. We suggest that the magma of the Aba andesites originated predominantly from a crustal source, with a minor mantle-derived component. The source region of the magma was likely at the crust-mantle boundary. The magma of the Wasai andesites resulted from partial melting of lithospheric mantle, which was probably metasomatized by fluids so that it was amphibole bearing. The petrogenesis of the Aba and Wasai andesites provides an additional evidence for the lithospheric delamination in the the Songpan-Garze fold belt, indicating that this process invoked mantle asthenosphere upwelling and caused the partial melting of remaining lithospheric mantle.CAI HongMing1,2, ZHANG HongFei1,2, XU WangChun1,2, SHI ZhangLiang1,2 & YUAN HongLin3 1 State Key Laboratory of Geological Processes and Mineral Resources, Wuhan 430074, China 2 Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China 3 State Key Laboratory of Continental Dynamics, Northwest University, Xi’an 710069, China 2010Science China Earth Sciences2010,53,9:14
12Evaluation on the accuracy of digital elevation models显示文摘There is a growing interest in investigating the accuracy of digital elevation model (DEM). However people usually have an unbalanced view on DEM errors. They emphasize DEM sampling errors, but ignore the impact of DEM resolution and terrain roughness on the accuracy of terrain representation. This research puts forward the concept of DEM terrain representation error (Et) and then investigates the generation, factors, measurement and simulation of DEM terrain representation errors. A multi-resolution and multi-relief comparative approach is used as the major methodology in this research. The experiment reveals a quantitative relationship between the error and the variation of resolution and terrain roughness at a global level. Root mean square error (RMS Et) is regressed against surface profile curvature (V) and DEM resolution (R) at 10 resolution levels. It is found that the RMS Et may be expressed as RMS Et = (0.0061 ( V+ 0.0052) ( R - 0.022 ( V + 0.2415. This result may be very useful in forecasting DEM accuracy, as well as in determining the DEM resolution related to the accuracy requirement of particular application.TANG Guo-an~1, Josef Strobl~2, GONG Jian-ya~3, ZHAO Mu-dan~1, CHEN Zhen-jiang~1 (1. Department of Geography, Northwest University, Xi’an 710069, China 2. Department of Geography and Geoinformation, Salzburg University, Hellbrunnerstr. 34, A-5020 Salzb 2001Journal of Geographical Sciences2001,11,2:13
13Inter-basin water transfer-supply model and risk analysis with consideration of rainfall forecast information显示文摘This paper develops a new inter-basin water transfer-supply and risk assessment model with consideration of rainfall forecast information. Firstly, based on the current state of reservoir and rainfall forecast information from the global forecast system (GFS), the actual diversion amount can be determined according to the inter-basin water transfer rules with the decision tree method; secondly, the reservoir supply operation system is used to distribute water resource of the inter-basin water transfer reservoir; finally, the integrated risk assessment model is built by selecting the reliability of water transfer, the reliability (water shortage risk), the resiliency and the vulnerability of water supply as risk analysis indexes. The case study shows that the inter-basin water transfer-supply model with rainfall forecast information considered can reduce the comprehensive risk and improve the utilization efficiency of water resource, as compared with conventional and optimal water distribution models.XI ShuFeng1, WANG BenDe1, LIANG GuoHua1, LI XueSen2 & LOU LiLi3 1 School of Civil and Hydraulic Engineering, Dalian University of Technology, Dalian 116024, China 2 Management Bureau of Tanghe Reservoir, Liaoyang 111000, China 3 Institute of Dalian Water Science, Dalian 116013, China 2010Science China(Technological Sciences)2010,53,12:12
14Primary scientific results of Chang'E-1 lunar mission显示文摘The strategic plan for the development of the unmanned Chinese Lunar Exploration Program is characterized by three distinct stages: 'orbiting around', 'landing on' and 'returning from' the Moon. The first Chinese lunar probe, Chang'E-1, which was successfully launched on October 24th, 2007 at Xichang Satellite Launch Center, and guided to crash on the Moon on March 1st, 2009, at 52.36°E, 1.50°S, in the north of Mare Fecunditatis, is the first step towards the 'orbiting around' stage. The Chang'E-1 mission lasted 495 days, exceeding the expected life-span by about four months. A total of 1.37 TB raw data was received from Chang'E-1. It was then processed into 4 TB scientific data products at various levels. Many scientific results have been obtained by analyzing these data, including especially the 'global lunar image from the first Chinese lunar explora- tion mission'. All scientific goals of Chang'E-1 have been achieved. It provides much useful materials for further advances of lunar sciences and planetary chemistry. Meanwhile, these results will serve as a firm basis for future Chinese lunar missions.OUYANG ZiYuan1,2, LI ChunLai1, ZOU YongLiao1, ZHANG HongBo1, Lü Chang1, LIU JianZhong1, LIU JianJun1, ZUO Wei1, SU Yan1, WEN WeiBin1, BIAN Wei1, ZHAO BaoChang3, WANG JianYu4, YANG JianFeng3, CHANG Jin5, WANG HuanYu6, ZHANG XiaoHui7, WANG ShiJin7, WANG Min1, REN Xin1, MU LingLi1, KONG DeQing1, WANG XiaoQian1, WANG Fang1, GENG Liang1, ZHANG ZhouBin1, ZHENG Lei1, ZHU XinYing1, ZHENG YongChun1, LI JunDuo1, ZOU XiaoDuan1, XU Chun1, SHI ShuoBiao1, GAO YiFei1 & GAO GuanNan1 1 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China 2 Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China 3 Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, China 4 Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China 5 Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China 6 Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China 7 Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190, China 2010Science China Earth Sciences2010,53,11:11
15Influence of differential settlement on pavement structure of widened roads based on large-scale model test显示文摘This study introduced at first the background of numerous highway widening projects that have been developed in recent years in China.Using a large ground settlement simulator and a fiber Bragg grating (FBG) strain sensor network system,a large-scale model test,with a similarity ratio of 1:2,was performed to analyze the influence of differential settlement between new and old subgrades on pavement structure under loading condition.The result shows that excessive differential settlement can cause considerable tensile strain in the pavement structure of a widened road,for which a maximum value (S) of 6 cm is recommended.Under the repetitive load,the top layers of pavement structure are subjected to the alternate action of tensile and compressive strains,which would eventually lead to a fatigue failure of the pavement.However,application of geogrid to the splice between the new and the old roads can reduce differential settlement to a limited extent.The new subgrade of a widened road is vulnerable to the influence of dynamic load transferred from the above pavement structures.While for the old subgrade,due to its comparatively high stiffness,it can well spread the load on the pavement statically or dynamically.The test also shows that application of geogrid can effectively prevent or defer the failure of pavement structure.With geogrid,the modulus of resilience of the subgrade is increased and inhomogeneous deformation can be reduced;therefore,the stress/strain distribution in pavement structure under loading condition becomes uniform.The results obtained in this context are expected to provide a helpful reference for structural design and maintenance strategy for future highway widening projects.Xiaolin Weng1,2,Wei Wang3 1 Key Laboratory for Special Area Highway Engineering of Ministry of Education,Chang’an University,Xi’an,710064,China 2 CCCC First Highway Consultants Co.,Ltd.,Xi’an,710068,China 3 Henan Vocational and Technical College of Communications,Zhengzhou,450005,China 2011Journal of Rock Mechanics and Geotechnical Engineering2011,3,1:11
16Thermoelastic properties of sandwich materials with pin-reinforced foam cores显示文摘Pin-reinforced foam is a novel type of sandwich core materials formed by inserting pins(trusses) into a foam matrix to create a truss-like network reinforced foam core.Upon loading,the pins deform predominantly by local stretching whilst the deformation of foam is governed by local bending.This paper presents a theoretical study on the thermoelasticity of pin-reinforced foam sandwich cores.To calculate the effective thermoelastic properties of pin-reinforced foam cores,the energy-based homogenization approach is employed to develop a micromechanics-based model,calibrated by the existing experimental data.It is found that the stiffness of the sandwich core is mainly governed by pin reinforcements:the foam matrix contributes little to sandwich stiffness.Compared with traditional foam cores without pin reinforcements,the changes in inplane thermal expansion coefficients are not vigorous as a result of pin reinforcements,while the through-thickness thermal expansion coefficient changes significantly.It is also demonstrated that it is possible to design materials with zero or negative thermal expansion coefficients under such a context.LU TianJian1,LIU Tao2,3 & DENG ZiChen2,4 1 MOE Key Laboratory of Strength and Vibration,School of Aerospace,Xi’an Jiaotong University,Xi’an 710049,China 2 Department of Engineering Mechanics,Northwestern Polytechnical University,Xi’an 710072,China 3 Department of Engineering,University of Cambridge,Cambridge CB2 1PZ,UK 4 State Key Laboratory of Structural Analysis of Industrial Equipment,Dalian University of Technology,Dalian 116024,China 2008Science China(Technological Sciences)2008,51,12:10
17Study on interaction between microtubule associated protein tau and prion protein显示文摘Microtubule-associated protein tau is considered to play roles in many neurodegenera-tive diseases including some transmissible spongiform encephalopathies.To address the possible molecular linkage of prion protein(PrP) and tau,a GST-fusion segment of human tau covering the three-repeat region and various PrP segments was used in the tests of GST pull-down and immuno-precipitation.We found tau protein interacted with various style prion proteins such as native prion protein(PrPC) or protease-resistant isoform(PrPSc) .Co-localization signals of tau and PrP were found in the CHO cell tranfected with both PrP and tau gene.The domain of interaction with tau was located at N-terminal of PrP(residues 23 to 91) .The evidence of molecular interactions between PrP and tau protein highlights a potential role of tau in the biological function of PrP and the pathogenesis of TSEs.HAN Jun1,ZHANG Jin1,2,YAO Hailan1,3,WANG Xiaofan1,LI Feng1,CHEN Lan1,4,GAO Chen1,GAO Jianmei1,NIE Kai1,ZHOU Wei1 & DONG Xiaoping11.State Key Laboratory for Infectious Diseases Prevention and Control,National Institute for Viral Disease Control and Pre-vention,Chinese Center for Disease Control and Prevention,Beijing 100052,China 2.School of Medicine,Xi’an Jiao-Tong University,Xi’an 710061,China 3.Tong-Ji Medical College,Hua-Zhong University of Science and Technology,Wuhan 430030,China 4.National Laboratory of Medical Molecular Biology,Institute of Basic Medical Science,Chinese Academy of Medical Sciences and Peking Union Medical College,Beijing 100005,China 2006Science China(Life Sciences)2006,49,5:10
18Large eddy simulation of flow in a street canyon with tree planting under various atmospheric instability conditions显示文摘In this work, a large eddy simulation (LES) model, which includes momentum and heat source (or sink) inside the tree planting layer, is proposed for the simulation of flow in a street canyon with tree planting. Vegetation canopy layer simulation shows that this model can be used to simulate the velocity distribution and temperature variation inside the canopy layer. Effects of atmospheric instability on flow and pollutant distribution in a street canyon with tree planting of an aspect ratio of 0.5 are studied. Results show that compared with the canyon with no tree planting (or the exposed street canyon), the canyon with tree planting shows a reduced wind circulation and pollutant exchange rate (PER) at the top layer of the street canyon, which induces the increase in the pollutant concentrations near road surface, leeward wall and windward wall. When street canyon atmosphere is under a strongly unstable condition, wind velocity decreases while pollutant concentration is increased in the areas near the street canyon top, road surface, leeward and windward walls, compared with the wind velocity in the street canyon with the neutral stratification. When street canyon atmosphere is under a weakly unstable condition, wind velocity weakens near the street canyon top and windward wall, but strengthens near the road surface and leeward wall, and pollutant concentration is decreased near the leeward and windward walls and is increased between the two rows of trees. When the street canyon atmosphere is under an unstable condition, PER is lower than that under the neutral stratification.GU ZhaoLin1, ZHANG YunWei2 & LEI KangBin3 1 School of Human Settlements and Civil Engineering, Xi’an Jiaotong University, Xi’an 710049, China 1 School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China 3 RIKEN Institute, Wako, Saitama, 351-0198, Japan 2010Science China(Technological Sciences)2010,53,7:10
19Proteomic analysis of mitochondria reveals a metabolic switch from fatty acid oxidation to glycolysis in the failing heart显示文摘This work characterizes the mitochondrial proteomic profile in the failing heart and elucidates the molecular basis of mitochondria in heart failure. Heart failure was induced in rats by myocardial infarction, and mitochondria were isolated from hearts by differential centrifugation. Using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight mass spectrometry, a system biology approach was employed to investigate differences in mitochondrial proteins between normal and failing hearts. Mass spectrometry identified 27 proteins differentially expressed that involved in energy metabolism. Among those, the up-regulated proteins included tricarboxylic acid cycle enzymes and pyruvate dehydrogenase complex subunits while the down-regulated proteins were involved in fatty acid oxidation and the OXPHOS complex. These results suggest a substantial metabolic switch from free fatty acid oxidation to glycolysis in heart failure and provide molecular evidence for alterations in the structural and functional parameters of mitochondria that may contribute to cardiac dysfunction during ischemic injury.WANG Jun1,2, BAI Ling1,2, LI Jing3, SUN ChaoFeng1,2, ZHAO Jin1, CUI ChangCong1,2, HAN Ke1,2, LIU Yu1,2, ZHUO XiaoZhen1,2, WANG TingZhong1,2, LIU Ping1,2, FAN FenLing1,2, GUAN YouFei3 & MA AiQun1,2 1 Department of Cardiology, First affiliated hospital of medical college of Xi’an Jiaotong University, Xi’an 710061, China 2 Ion Channel Disease Laboratory, Key Laboratory of Environment and Genes Related to Diseases of Education Ministry, Xi’an 710061, China 3 Department of Physiology and Pathophysiology Key Laboratory of Molecular Cardiovascular Sciences of the Ministry of Education, Peking University Health Science Center, Beijing 100083, China 2009Science China(Life Sciences)2009,52,11:10
20Ultralight X-type lattice sandwich structure (Ⅱ):Micromechanics modeling and finite element analysis显示文摘The methods of homogenization and finite elements are employed to predict the effective elastic constants and stress-strain responses of a new type of lattice structure,the X-structure proposed by the authors in a companion paper. It is shown that in most cases the predictions by the equivalent homogenization theory agree well with the experimental and 3-dimensional finite element calculated results. The theoretical and numerical study supports the argument that the X-structure is superior to the pyramid lattice structure in terms of mechanical strength.ZHANG QianCheng1,CHEN AiPing 2,CHEN ChangQing2,3 & LU TianJian2 1 State Key Laboratory for Mechanical Behavior of Materials,School of Material Science and Engineering,Xi’an Jiaotong University,Xi’an 710049,China 2 MOE Key Laboratory for Strength and Vibration,School of Aerospace,Xi’an Jiaotong University,Xi’an 710049,China 3 Department of Engineering Mechanics,AML,Tsinghua University,Beijing 100084,China 2009Science China(Technological Sciences)2009,52,9:9
返回顶部 每页显示:
共6页 首页 上一页 第1页 下一页 末页 /6 跳转

网站首页 | 关于我们 | 联系我们 | 产品服务 | 客服中心 | 广告服务 | 版权声明 | 网站联盟 | 友情链接 | 售卡网点

版权所有© 渝B2-20050021-1 渝公网安备 50019002500403号 违法和不良信息举报中心

互联网出版许可证 新出网证(渝)字10号 全国400电话 - 免长途话费