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Interannual variability of Antarctic Oscillation and its influence on East Asian climate during boreal winter and spring

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science China Earth sciences 2006年第5期49卷 554-560页

作者： FAN Ke1,2.3.& WANG Huijun2.1. Nansen-Zhu International Research Center, institute of Atmospheric Physics, Chinese Academy of {2.s, Beijing 10002., China 2. Department of Atmospheric {2., Yunnan {3., Kunming 650091, China 3. Graduate {3. of the Chinese Academy of {2.s, Beijing 100049, China 1. Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. Department of Atmospheric science Yunnan University Kunming 650091 China 3. Graduate university of the Chinese Academy of {2.s Beijing 100049 China

The interannual variability of Antarctic Oscillation (AAO) and its influence on East Asian climate during both boreal winter and spring are addressed. The results show that the positive AAO anomaly decreases the cold activity over East Asia during both boreal winter and spring. AAO-related barotropic meridional teleconnection from Antarctic to Arctic is found through analysis of mean me- ridional circulations. This meridional teleconnection is remarkable over Eurasia during boreal winter and over the Pacific Ocean during boreal spring. The results also show that zonal mean zonal wind at high latitudes in Southern Hemisphere has well positive correlation with that of Eurasia during boreal winter and has negative correlation with Pacific North American teleconnection (PNA) during boreal spring, which again display the meridional teleconnection. Thus, local meridional teleconnection is a possible linkage for interaction of circulations at mid-high latitudes between both hemispheres.

关键词： Antarctic Oscillation, Eurasian west wind, meridional teleconnection, mean meridional circulation.

Holocene grassland vegetation, climate and human impact in central eastern Inner Mongolia

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science China Earth sciences 2005年第7期48卷 1025-1039页

作者： HUANG Fei1, Kealhofer Lisa2. XIONG Shangfa3.& HUANG Fengbao1 1. nanjing {2. of Geology and Paleontology,Chinese Academy of {2.s,nanjing 2.0008,China 2. Anthropology and Sociology Department,Santa Clara university,CA 95053.USA 3. {2. of Geology and Geophysics,Chinese Academy of {2.s,Beijing 10002.,China nanjing institute of Geology and Paleontology Chinese Academy of Sciences Nanjing 210008 China Anthropology and Sociology Department Santa Clara University CA 95053 United States institute of Geology and Geoohysics Chinese Academy of Sciences Beijina 100029 China

Phytolith and pollen preserved in the Taipusi Banner paleosol profile, central eastern Inner Mongolia, provide evidence of Holocene grassland vegetation, climate and human impact. The combined phytolith and pollen records reveal a major change in vegetation composition about 5000 a BP. Before 5000 a BP, the vegetation was dominated by Aneurolepidium Chinese-Stipa grandis grassland of C4 grasses. After 5000 a BP, C4 grasses rapidly retreated, indicating a shift to colder and more arid conditions. The gradual invasion of Stipa krylovii, Ag-ropyron desertorum, Ephedra, Chenopodiaceae and Caragana reveal the onset of grassland degeneration. Between 10000 and 872. a BP, the Aneurolepidium Chinese-Stipa grandis grassland included a small proportion of Artemisia shrub and Echionopos type plants, implying a strong winter monsoon and very weak summer monsoon. From 872. to 7000 a BP, C4 grasses were common, indicating a strengthening of the summer monsoon. Between 7000 and 5000 a BP, the Holocene thermal maximum was evident, with a significant expansion of C4 grasses and the presence of some trees (such as Pinus and Betula, and so on) in or near the study site. From 42.0?000 a BP, a sandy grassland of Artemisia and Agropyron desertorum together with Aster-type taxa occurred. Precipitation amelioration took place between {2.00 and 2.70 a BP, with a rapid development of Echinops type plants and a small expansion of C4 grasses. From 2.70 a BP to present, human activities accelerated the process of grassland degeneration.

关键词： phytolith and pollen records grassland environment change human impact Holocene central eastern Inner Mongolia.

Analysis on cohesive crack opening displacement considering the strain softening effect

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science China(Physics,Mechanics & Astronomy) 2006年第1期49卷 88-101页

作者： WANG Limin1, XU Shilang2.& ZHAO Xiqiang3.1. Mechanics Department, Shandong university of {2., Zibo 2.5049, China 2. Civil Engineering Department, Dalian university of {2., Dalian 11602., China 3. Mathematics Department, Ocean university of China, Qingdao 2.6071, China Mechanics Department Shandong University of Technology Zibo 255049 China Civil Engineering Department Dalian University of Technology Dalian 116024 China Mathematics Department Ocean University of China Qingdao 266071 China

In order to investigate the crack propagation in quasi-brittle materials like rock, ceramic and concrete, Hillerborg and his co-researchers abstracted the fracture process zone in front of a stress free crack in terms of a “fictitious crack zone”. On the fictitious crack zone, cohesive stresses distribute following a given softening relationship of stress vs. crack opening. Based on the polynomial or power series expression of cohesive crack opening displacement, the relationship of the cohesive stress vs. the crack opening displacement is established using elastic theory and integral equation, and some unknown physics variables are obtained using variation approach. The calculation results gained in this paper are close to the experimentally test ones.

关键词： cohesive crack, softening, dissipation work, variation approach.

Wavelet estimation of the diffusion coefficient in time dependent diffusion models

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science China Mathematics 2007年第11期50卷 1597-1610页

作者： Ping CHEN~(1,2.) Jin-de WANG~1 1 Department of Mathematics,nanjing university,nanjing 2.0093.China 2.School of {3.,nanjing university of {3. and technology,nanjing 2.0094,China Department of Mathematics Nanjing University Nanjing 210093 China School of science Nanjing University of Science technology Nanjing 210094 China

The estimation problem for diffusion coefficients in diffusion processes has been studied in many papers,where the diffusion coefficient function is assumed to be a 1-dimensional bounded Lipschitzian function of the state or the time *** is no previous work for the nonparametric estimation of time-dependent diffusion models where the diffusion coefficient depends on both the state and the *** paper introduces and studies a wavelet estimation of the time-dependent diffusion coefficient under a more general assumption that the diffusion coefficient is a linear growth Lipschitz *** the properties of martingale,we translate the problems in diffusion into the nonparametric regression setting and give the Lr convergence rate.A strong consistency of the estimate is *** this result one can estimate the time-dependent diffusion coefficient using the same structure of the wavelet estimators under any equivalent probability *** example,in finance,the wavelet estimator is strongly consistent under the market probability measure as well as the risk neutral probability measure.

关键词： wavelet estimation time-dependent diffusion coefficient linear growth condition strong consistency

A new sequential learning algorithm for RBF neural networks

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science China(Technological sciences) 2004年第4期47卷 447-460页

作者： YANG Ge1, LV Jianhong1 & LIU Zhiyuan2.1. Department of Power Engineering, Southeast university, nanjing 2.0096, China 2. Department of Power Engineering, nanjing {3. of technology, nanjing 2.0013. China 1. Department of Power Engineering Southeast University 210096 Nanjing China 2. Department of Power Engineering Nanjing Institute of Technology 210013 Nanjing China

Due to their inherent imperfections, it is hard to use the static neural networks for nonlinear time-varying process modeling and prediction, and the minimal resource allocation network (MRAN) is difficult to be realized for its too many regulation parameters. A new sequential learning algorithm for radial basis function (RBF) neural networks based on local projection named Local Projection Network (LPN) is proposed in this paper. The results of validation for several benchmark problems with the new algorithm show that the presented LPN not only has the same level as M-RAN in network size and precision of the outputs, but also has fewer regulation parameters and is more predictable.

关键词： radial basis functions, local projection network, minimal resource allocation network, learning algorithm.

Case studies on mesoscale structures of heavy rainfall system in the Yangtze River generated by Meiyu front

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science China Earth sciences 2005年第8期48卷 1303-1311页

作者： LIU Liping1, RUAN Zheng1 & QIN Danyu2.1. Chinese Academy of Meteorological sciences, Beijing 100081, China 2. nanjing{2. of {3., nanjing 2.0044, China 1. Chinese Academy of Meteorological sciences 100081 Beijing China 2. nanjing institute of{2. 210044 Nanjing China

A heavy rainfall system was observed over the Yangtze River during Meiyu season by using dual-Doppler radar systems in the field experiment conducted by the project of National Fundamental Research planning “Research on formation mechanism and the prediction theory of hazardous weather over China”. The three-dimensional mesoscale kinematic structure and process of a heavy rain on 2. and 2.1}July, 2.02.are investigated by using the radial velocity and dual-Doppler radar technique. The results show that a southwest-northeast oriented rain band with the length of about 1000 km involves numbers of meso-β or meso-γ-scale convective cells with the size of 2.―50 km. The heavy rain band in the middle reaches of the Yangtze River ex-ists in a low-level wind shear. The interaction between southwest low-level jet on the southern side of wind shear and east wind on the northern side formed the updraft. The wind disturbance, wind shear and convergence generate the convective action. The new cell developed in right rear flank of rain band and moved to the southwest wind area, where the vapor is abundant. This kind of echo can last a long time and developed well. The strong convective echoes are often ac-companied by the meso-γ-scale vortex and convergence.

关键词： heavy rainfall in Meiyu front, mesoscale structure, dual-Doppler radar, middle reaches of the Yangtze River, low-level jet.

Surface configurations during annealing of sputter-deposited NiTi thin films

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Chinese science Bulletin 1997年第23期42卷 2019-2020页

作者： GONG Fengfei, JIANG Enyong, SHEN Huimin and WANG Yening1. Department of Applied Physics, Tianjin university, Tianjin 3.0072.The National Laboratory of Solid State Microstructures, {2. university, {2. 2.0008 Center for Advanced Studies in science and technology of Microstructures, {2. 2.0093. China 2. Department of Physics, Tianjin university, Tianjin 3.0072. China 3. National Laboratory of Solid State Microstructures, {2. university, {2. 2.0008, Center for Advanced Studies in science and technology of Microstructures, {2. 2.0093. China. Department of Applied Physics Tianjin University Tianjin The National Laboratory of Solid State Microstructures Nanjing University Nanjing Center for Advanced Studies in science and technology of Microstructures Nanjing China Department of Physics Tianjin University Tianjin China National Laboratory of Solid State Microstructures Nanjing University Nanjing

SPUTTER-DEPOSITED NiTi thin films are becoming more and more important because of their po-tential applications to the intelligent thin-film systems. The as-deposited NiTi thin films pre-pared by magnetron sputtering are generally amorphous. Because the amorphous NiTi thinfilms cannot show shape memory effect, they should be crystallized under appropriate anneal-

关键词： NiTi Surface configurations during annealing of sputter-deposited NiTi thin films

Distribution characteristics of terrestrial heat flow density in Jiyang depression of Shengli Oilfield, East China

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science China Earth sciences 2004年第9期47卷 804-812页

作者： GONG Yuling1,2. WANG Liangshu1, LIU Shaowen1, LI Cheng1, HAN Yongbing1, LI Hua1, LIU Bo1 & CAI Jingong3.1. Department of Earth sciences, {2. {2., {2. 2.0093. China 2. Department of Exploration and Information technology of East China institute of technology, Fuzhou 3.4000, China 3. Earth science Institution of Shengli Oilfield, Dongying 2.7015, China Department of Earth sciences Nanjing University Nanjing 210093 China Department of Exploration and Information technology of East China institute of technology Fuzhou 344000 China Earth science Institution of Shengli Oilfield Dongying 257015 China

Based on the geo-temperature data of 13.systematically continuous temperature log curves and 700 testing oil boreholes in Jiyang depression, Shengli Oilfield, and the measured thermal conductivities of 47 rock samples, the terrestrial heat flow densities of 114 boreholes of Jiyang depression and its surrounding areas are determined, including 13.of those data derived from systemically continuous temperature logging. The results show that Jiyang depression has a relatively high background heat flow with an average value (65.8 5.4) mW/m2. The lateral variation of heat flow in basin has negative correlation with basement depth. Moreover, heat flow of uplift areas with shallower basement is high, so are those of regions with volcanic rocks, and those of depression areas with deep basement are relatively low. The heat flow densities of different structural units of Jiyang depression can be summarized as follows: The average heat flow value of Zhanhua sag is (67.4 5.3. mW/m2. higher than that of the whole basin, that of Dongying sag is (66.0 6.1) mW/m2. and that of Chezhen sag is (65.1 3.7) mW/m2. It is apparent that these latter two values are approximate to the average value of the whole Jiyang depression, while the average value of Huimin sag is (63.65.0) mW/m2. lower than that of the whole basin. In fact, the basement depth and the distribution framework of uplift and depression areas are all controlled by the process of lithosphere extension. In addition, the distribution of volcanic rocks in basin is also relatively close to this extension geodynamic process. In summary, the distribution characteristics of terrestrial heat flow of Jiyang depression is determined by the Cenozoic tectono-thermal events of this region.

关键词： Jiyang depression, terrestrial heat flow, thermal conductivity.

CMC surfaces in the hyperbolic 3.space

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Chinese science Bulletin 1998年第7期43卷 547-550页

作者： YU Zuhuan 1, 2.and LI Zhenqi 1, 3.1. institute of Mathematics, Fudan {2., Shanghai 2.043., China 2. Department of Mathematics,Sichuan Union {2., Chengdu 610064, China 3. Department of Mathematics, Nanchang {2., Nanchang 3. nstitute of Mathemalics Fudan University Shanghai China Department of Mathematics Sichuan Union University Chengdu China Department of Mathematics Nanchang University Nanchang China

CMC-H surfaces satisfying H≥1 are studied. It is proved that these surfaces possess a natural representation which is a generalization of the Bryant’s result.

关键词： hyperbolic space CMC surface Weierstrass representation.