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Comparative analysis of temperature and CO2.fluxes for winter wheat in Tibetan Plain and North china Plain using the EMD method

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Progress in Natural Science:Materials International 2006年第10期16卷 1066-1071页

作者： JIANG Zhaoyang, YU Qiang, LEI Shuhe, WANG Tianduo, SUN Xiaomin and ZHANG Renhua ( Chinese Academy of Meteorological Science, beijing 100081, china Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, beijing 100101, china Mathematics Department, Ocean university of china, Qingdao 2.6071, china Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 2.003.6} china) [a]Chinese Academy of Meteorological Science Beijing China [b]Chinese Academy of Sciences Institute of Geographic sciences and Natural Resources Research Beijing China [c]Mathematics Department Ocean University of China Qingdao China [d]Chinese Academy of Sciences Shanghai Institute of Plant Physiology and Ecology Shanghai China

Comparative study of spectral properties of temperature and CO2.fluxes measured by eddy covariance method at Yucheng (3.°57'N, 116°3.'E, 2. m a.s.l., in the North china Plain) and at Lhasa (2.°41'N, 91°2.'E, 3.88 m a.s. 1., on the Tibetan Plateau) is described using the empirical mode decomposition (EMD) method. The main results are: (1) The intrinsic oscillation modes or intrinsic mode functions (IMFs) were extracted from data of temperature ( T) and CO2.fluxes (F) measured at Yucheng ( T1 and F1) and Lhasa ( T2.and F2. . (2. Hilbert transform was applied to these IMF components, then the Hubert-Huang spectra and the marginal spectra of these data were obtained. (3. Comparison of temperature and CO2.fluxes in North china Plain and on Tibetan Plain illustrated that the characteristic frequencies corresponding to T1, F1, T2.and F2.are 0.05 Hz, 0.03.Hz, 0.014 Hz and 0.005 Hz, respectively.

关键词： empirical mode decomposition (EMD) intrinsic mode function (IMF) flux Hilbert transform wheat Tibet.

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CREEP BEHAVIOR OF γ-TiAl POLYSYNTHETICALLY TWINNED CRYSTALS

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Acta Metallurgica Sinica(English Letters) 1996年第6期9卷 577-583页

作者： Y.G. Zhang J.G. Lin Y.J. Zhou and C.Q. Chen(Department of Materials Science and Engineering, beijing university of Aeronautics and Astronautics,beijing 100083.{3. beijing Univ of Aeronautics and Astronautics Beijing China

Creep behavior of γ-TiAl polysynthetically twinned (PST) crystals has been investigated at temperature between 700 and 800℃. The results show that the creep behavior of the crystals is strongly dependent on the angle between the lamellar boundaries and loading axis. The samples with the angle φ=45 deg. have the lowest creep resistance, while the samples with φ=0 deg., rather than φ=90 deg.,show the strongest creep resistance. The stress exponent and creep activation energy for the power law creep vary with the orientations of samples, which indicates that the creep mechanisms of the samples with different angle φ are quite *** deformation substructure has been examined by transmission electron microscopy (TEM),which shows that both gliding, perhaps also climbing, of dislocations and twinning contribute to the creep deformation with some particular observation in the samples with φ=90 deg. in which rotation of the γ plates across a true twin boundary was observed, which indicates the deformation mechanism of the samples is different from the samples in other orientations.

关键词： TiAl alloy PST crystal creep behavior lamellar microstructure

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Adaptive model selection for fading distribution and signal detection in free-space optical communications

Adaptive model selection for fading distribution and signal ...

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中国通信学会第六届学术年会

作者： Luo Chang~(1,2.,Li Ji-ye~2.(1 graduate {3. of Chinese Academy of Sciences,{2. 100190,china 2.Center for Space Science and Applied Research Chinese Academy of Sciences,{2. 100190,china)

Free-space optical communications(ultraviolet and infrared communications) have emerged as a viable alternative to RF communication for many *** communication system even can provide non-line-of-sight links by exploiting atmospheric scattering of *** turbulence can causes fluctuations in the intensity of the received signal,impairing link *** theoretical models about atmospheric turbulence have been proposed to describe turbulence-induced intensity *** some models are simple to implement,they are often used to model some turbulence *** have excellent fit with measurement data for a wide range of turbulence conditions,but they are complex and difficult to *** this paper,we present an adaptive method to select the different simple turbulence model based on the scintillation index in different turbulence conditions and detect the signals in the Poisson and Gauss regime,when the light fluctuations exit in ultraviolet and infrared communication.

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EXPERIMENTAL RESEARCH ON STRESS INTENSITY FACTOR K_Ⅲ FOR 3.D CRACK BY CAUSTICS

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Chinese Journal of Aeronautics 1997年第4期10卷 38-43页

作者： Wu Dafang, Gao Zhentong (Institute of Solid Mechanics, beijing university of Aeronautics and Astronautics, beijing, 100083.{3.)

An experimental technique for determining the anti plane stress intensity factor K Ⅲ of a three dimensional crack, which is very difficult to obtain by other experimental methods, has been presented by using reflected caustics in combination with the stress freezing and stress releasing technique. The results of this experimental method coincided favorably with the theoretical analysis results of Tweed and Rooke.

关键词： caustics (optics) three dimensional bodies cracks stress intensity factors

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A MICROMECHANICS CONSTITUTIVE MODEL FOR PURE DILATANT MARTENSITIC TRANSFORMATION OF ZrO2.CONTAINING CERAMICS

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Acta Mechanica Sinica 1990年第2期6卷 141-150页

作者： Sun Qingping Yu Shouwen Hwang Kehchih (Dept.of Engng.Mech.,Tsinghua university,beijing,{2.) 1. Dept. of Engng. Mech. Tsinghua University Beijing China

A new micromechanics constitutive model for pure dilatant transformation plasticity of structure ceramics is proposed in this *** on the thermodynamics,micromechanics and microscale t→ m trans- formation mechanism analysis of the TZP and PSZ ZrO2.containing ceramics,an analytic expressions of the Helmholtz and complementary free energy of the constitutive element for the case of pure dilatant transforma- tion is derived for the first time in a self-consistent *** the analysis of energy dissipation in the for- ward and reverse transformations,the mieromechanics constitutive law is derived in the framework of Hill-Rice’s internal variable constitutive theory.

关键词： constitutive element microscopic and macroscopic quantities internal variables free energy thermodynamic force pure dilatant transformation inclusions and matrix

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The Effect of Nb on Mechanical Properties of Quenching and Partitioning Steels

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Journal of Iron and Steel Research International 2011年第S1期18卷 306-309页

作者： ZHU Shuai,KANG Yong-lin,REN Kang-kang,WANG Chuan (School of Materials Science and Engineering.university of Science and Technology beijing,beijing 100083.{3.) Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

In order to study the effect of alloy elements on mechanical properties of quenching and partitioning steels,the Q and P heat treatments on different chemical composition steels were carried on in *** tensile test results indicated the strength of Nb+Ti-bearing steel was not increasing as expected,but lower than that of the Nb+Ti-free steel,and the elongation was raised to 2.% from 9%.The Nb+Ti-bearing steel microstructures after tensile test were detected by TEM and found a certain amount of twins in the deformed microstructure while the deformed microstructure mainly was lath martensite in Nb+Ti-free steel,which means the addition of Nb and Ti elements could cause the twinning induced plasticity by inhibiting the phase transformation from austenite to *** on above analysis,adding trace Nb element could greatly increase the stacking fault energy of the retained austenite,which is beneficial to the formation of twins,and the formation of twins would lower the strength slightly and raise the elongation drastically.

关键词： quenching and partitioning twinning induced plasticity niobium stacking fault energy

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THE DEVELOPMENT OF A MICROCOMPUTER PROGRAM FOR THE THREE-DIMENSIONAL NON-LINEAR FEM

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中国有色金属学会会刊：英文版 1993年第1期3卷 10-15,26页

作者： Ma. Mingjun Liao, Guohua Fang Zulie university of Science Technology of beijing, beijing 100083.{3.

This paper presents a microcomputer program system for the three-dimensional non-linear finite element method (FEM), which is developed for applications in mining engineering, such as excavation, filling, caving, damming, etc. Our attention is focused on some of the key aspects of the programing techniques for an applicable microcomputer program, such as the structure of the program, data processing in the core, communication between the core and mass storage, input and output systems, etc. In the last part of this paper, two test examples are presented verifying the computational accuracy of this programing system and illustrating its applicability in practical engineering.

关键词： Finite Element Method (FEM) Microcomputer Mining Engineering

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A skarn-type lead-zinc deposit related to low ^(18)O magma

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Chinese Science Bulletin 1997年第19期42卷 1636-1640页

作者： MU Baolei, SHAO Jian, WANG Guanyu, YAN Guohan and Al YongfuDepartment of Geology , Peking university, beijing 100871,{2. Department of Geology Peking University Beijing China

THE Baiyinnuo skarn-type lead-zinc deposit occurs within the Da Hinggan Mountains, in theBalinzuo County 3.0 km north of the Chifeng City, the Inner Mongolia Autonomous *** minerals and relevant igneous rocks in the deposits are extremely depleted in 18O. Thephenomena are also found in other skarn-type lead-zinc deposits in the Baiyinnuo region andshould be further studied.

关键词： low 18O magma skarn melasomatic fluid.

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Negative regulation of TGF-β signaling in development

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Cell Research 2004年第6期14卷 441-449页

作者： Ye Guang CHEN, An Ming MENG The State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua university, beijing 100084,{2. Department of Biological Sciences and Biotechnology The State Key Laboratory of Biomembrane and Membrane Biotechnology Tsinghua University Beijing 100084 China

The TGF-β superfamily members have important roles in controlling patterning and tissue formation in both invertebrates and vertebrates. Two types of signal transducers, receptors and Smads, mediate the signaling to regulate expression of their target genes. Despite of the relatively simple signal transduction pathway, many modulators have been found to contribute to a tight regulation of this pathway in a variety of mechanisms. This article reviews the negative regulation of TGF-β signaling with focus on its roles in vertebrate development.

关键词： TGF-β BMP Nodal Activin antagonist development negative regulation.

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Solution of stress intensity factors of multiple cracks in plane elasticity with eigen COD formulation of boundary integral equation

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Journal of Shanghai university(English Edition) 2011年第3期15卷 173-179页

作者：郭钊马杭 Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Department of Mechanics College of Sciences Shanghai University

The concept of eigen crack opening displacement （COD） can be defined as the COD of a crack in infinite plate under the tractions acting on the crack surface. By introducing this concept, the eigen COD formulation of boundary integral equation is proposed in this paper, together with the solution procedures for multiple crack problems in plane elasticity. With the proposed approach, the multiple crack problems can be solved with the conventional displacement discontinuity boundary integral equations in an iterative fashion with a small size of system matrix as that in the numerical Green’s function （NGF） approach but without the trouble to determine the complementary solutions since the standard boundary element discretization on the crack surface is no longer required with the proposed approach. Some numerical examples computing the stress intensity factors are presented and compared with those in literature to show the accuracy and the effectiveness of the proposed approach.

关键词： crack opening displacement (COD) multiple cracks stress intensity factor boundary integral equation iteration

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