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ON THE UNIQUE SOLVABILITY OF THE NONLINEAR SYSTEMS IN MDBM

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Journal of Computational Mathematics 1994年第1期12卷 55-60页

作者： Kuang Jiao-xun Lu Lian-hua (department of Mathematics, Shanghai Normal university, Shanghai, {2.) SHANGHAI NORMAL UNIV DEPT MATHSHANGHAIPEOPLES R CHINA

To obtain the approximate solution of the nonlinear ordinary differential equations requires the solution to systems of nonlinear equations. The authors study the conditions for the existence and uniqueness of the sol... 详细信息

关键词： DL ON THE UNIQUE SOLVABILITY OF THE NONLINEAR SYSTEMS IN MDBM

Galvanic effects on cavitation damage for 1Cr13.stainless steel

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Journal of university of Science and Technology Beijing 2003年第4期10卷 33-37页

作者： Dongbai Sun, Xia Bai, Hongying Yu, Huimin Meng, and Huiqing LiUNDP-Beijing Corrosion and Protection Center, university of Science and Technology Beijing, Beijing 100083. {2. UNDP Corrosion Ctr. Univ. of Sci. and Technol. Beijing Beijing 100083 China

Based on the electric-spark principle, a new kind of cavitation damagetesting apparatus was designed, which could produce the bubble. Bubbles collapsed and acted on asmall surface area of the alloy surface, so an intensive electrochemical inhomogenous state would beinduced and lead to the existence of surface galvanic effect on the alloy. The galvanic effect of1Cr13.SS during cavitation damage has been quantitatively investigated in NaCl solution. The resultsshow that intensive galvanic effect of 1Cr13.SS during cavitation damage appears the potential ofthe damaged area shifting negatively with the bubble collapse and simultaneously the galvaniccurrent generates. The mass loss of alloy due to cavitation increases with the bubble quantity, andincreases with the increasing of Cl- content. And both the total mass loss and the mass loss due togalvanic corrosion increase linearly with the area ratio of cavitation damaged to undamaged *** surface galvanic effects speed up the dissolution rate of the alloy, which, in turn,accelerates the mechanical damage, and aggravates the mass loss of the alloy. It has been furtherconfirmed that the mass loss due to the surface galvanic effect can be decreased by catholicprotection.

关键词： cavitation damage galvanic effect area ratio mass loss

Surface hardening of Fe-based alloy powders by Nd:YAG laser cladding followed by electrospark deposition with WC-Co cemented carbide

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Rare Metals 2010年第4期29卷 380-384页

作者： WANG Jiansheng,MENG Huimin,YU Hongying,FAN Zishuan,and SUN Dongbai School of Materials Science and Engineering,university of Science and Technology Beijing,Beijing 100083.{2. School of Materials Science and Engineering University of Science and Technology Beijing Beijing China

This paper presents the results of a study concerned with the surface hardening of Fe-based alloys and WC-8Co cemented carbide by inte- grating laser cladding and the electrospark deposition processes. Specimens of low carbon steel were processed firstly by laser cladding with Fe-based alloy powders and then by electrospark deposition with WC-SCo cemented carbide. It is shown that, for these two treatments, the electrospark coating possesses finer microstructure than the laser coating, and the thickness and surface hardness of the electrospark coating can be substantially increased.

关键词： laser cladding electrospark deposition surface hardening Fe-based alloy cemented carbide

FATIGUE FRACTURE BEHAVIOR OF LOW CARBON MARTENSITE AND MARTENSITE/BAINITE DUPLEX STRUCTURE IN STEEL 2.CrMnMo

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Acta Metallurgica Sinica(English Letters) 1992年第3期5卷 212-217页

作者： LI Yongjun Xi′an Jiaotong university,Xi′an,china Xi'an Jiaotong Univ Xi'an China

Fatigue crack propagation rate,da/dN,and threshold stress intensity range,ΔK_(th),of steel 2.CrMnMo containing low carbon martensite or low carbon martensite/bainite(LCM/B) duplex structure,obtained by oil quenching and austempered at 3.0℃,have been measured using specimens under four-point *** was also made of the crack path and fracture morphology with relation to *** formation of LCM/B duplex structure,which caused by 2.% lower bainite after short-time isothermal treatment,may re- markably increase ΔK_(th)and considerably decrease da/*** effect of microstructure on da/dN and ΔK_(th)was discussed with the emphasis on the crack propagation path.

关键词： low carbon martensite duplex structure fatigue crack propagation rate threshold stress intensity range crack path

Mechanical Analysis for Progressive Failure of Debris Landslide

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Journal of Mountain Science 2011年第2期8卷 328-335页

作者： MIAO Haibo YIN Kunlong LI Deying Faculty of Engineering China University of Geosciences Wuhan 430074 China

It is of significance to research failure mechanism of debris landslides that are widespread in the Three Gorges Reservoir Area. Based on the statistical analysis of the developmental law and failure mode of debris landslides in the Three Gorges Reservoir, the mode of progressive failure is found. The mechanical model for progressive failure of debris landslides with two slip bands is also established by applying slice method. According to the results of the downslide force between adjacent slices, if the downslide force of lower slice is larger than zero, the slice fails along the major sliding surface, otherwise it is stable. In result, the failure range is obtained. The stress function can be determined through dimensional analysis of failure slice. According to static boundary conditions of the slice, stress state of any point in the slice can be obtained. Then stress state of any point in the secondary slip band can also be established. The failure of the secondary slip band is judged on the basis of Mohr-Coulomb failure criterion. Therefore, a mechanical method is proposed to analyze the progressive failure of debris landslide with two slip bands.

关键词： Debris landslide Progressive failure Mechanical model

Feedback between tidal hydrodynamics and morphological changes induced by natural process and human interventions in a wave-dominated tidal inlet: Xiaohai, Hainan, china

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Acta Oceanologica Sinica 2009年第3期28卷 93-113页

作者： GONG Wenping SHEN Jian JIA Jianjun School of Marine Science Sun Yat-Sen University Guangzhou 510275 China Virginia Institute of Marine Science College of William and Mary Gloucester Point VA23062 USA Key Laboratory of Submarine geosciences Second Institute of Oceanography State OceanicAdministration Hangzhou 310012 China

The feedback between morphological evolution and tidal hydrodynamics in a wave-dominated tidal inlet, Xiaohai, china is investigated through data analysis and numerical model experiments. Historically, Xiaohai Inlet had two openings, located at the north and south of Neizhi Island （a rocky outcrop）, respectively. The evolution of Xiaohai Inlet was dominated by the natural process before 1972. In addition to the natural process, human interventions, including the closure of the north opening, 50% of freshwater reduction, and increase of land reclamation, have altered tidal hydrodynamics and morphological evolution since 1972. A series of numerical model simulations were conducted to investigate the influence of morphological changes on the hydrodynamics and the influence of human activities on the inlet evolution. The natural process has caused narrowing and shoaling of the inlet throat, development of the flood-tidal delta, and shoaling of the tidal channel inside the lagoon. Human interventions have accelerated these changes. Consequently, the tidal propagation from the offshore into the lagoon has been impeded and the tidal energy has been dissipated substantially. Tidal current has changed from ebb-dominant to flood-dominant in most parts of the inlet system whereas the inlet throat has remained as ebb-dominant, the tidal prism has decreased consistently, and sediment has continued to deposit inside the inlet. As a result, the changes of morphology, hydrodynamics, and sediment transport show a positive feedback. The human interventions have had both advantageous and adverse influences on the stability of the inlet. The closure of the North Opening has decreased the longshore sediment input to the inlet, and increased the tidal prism, ebb velocity, and sediment transport in the south opening, thus enhancing the inlet＇s stability. However, reducing the river discharge and landfill of the tidal flats has resulted in a decrease of the tidal prism, the ebb velocity, a

关键词： morphological evolution tidal hydrodynamics ELCIRC Hainan china

Global analyses of crisis and stochastic bifurcation in the hardening Helmholtz-Duffing oscillator

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Science china(Technological Sciences) 2010年第3期53卷 664-673页

作者： XU Wei & YUE XiaoLe department of Applied Mathematics,Northwestern Polytechnical university,Xi’an 710072.{2. 1. department of Applied Mathematics Northwestern Polytechnical University Xi’an 710072 China

Crisis and stochastic bifurcation of the hardening Helmholtz-Duffing oscillator are studied by means of the generalized cell mapping method using *** the system subject to a single deterministic harmonic excitation,our study reveals that a series of crisis phenomena can occur when the system parameter passes through different critical values,including chaotic boundary crisis,regular boundary crisis and interior crisis.A chaotic boundary crisis due to the collision of regular attractor with chaotic saddle embedded in a fractal basin boundary and an interior crisis due to the collision of regular attractor with chaotic saddle of its attraction basin are discovered.A new phenomenon,namely the global properties of dynamical system show symmetric as system parameter is varied,can be also revealed according to our *** the system subject to a combination of a deterministic harmonic excitation and a random excitation,it is found that stochastic bifurcation,defined as a sudden change in character of a stochastic attractor,can occur one after another when the noise intensity passes through different critical *** kind of stochastic bifurcation corresponds to stochastic crisis *** study also reveals that the generalized cell mapping method using digraph is a powerful tool not only for the crisis behavior analysis of deterministic system,but also for the global property analysis of stochastic bifurcation.

关键词： crisis stochastic bifurcation hardening Helmholtz-Duffing oscillator generalized cell mapping method using digraph

Effect of Bcl-2.and caspase-3.on calcium distribution in apoptosis of HL-60 cells

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Cell Research 2000年第3期10卷 213-220页

作者： ZHANG MIN, HONG QING ZHANG, SHAO BAI XUE (department of Biology, Beijing Normal university, Beijing 100875, {2.) departmentofBiology BeijingNormalUniversityChina.

Apoptosis manifests in two major execution programs downstream of the death signal: the caspase pathway and organelle dysfunction. An important antiapoptosis factor, Bcl-2.protein, contributes in caspase pathway of apoptosis. Calcium, an important intracellular signal element in cells, is also observed to have changes during apoptosis, which maybe affected by Bcl-2.protein. We have previously reported that in Harringtonine (HT) induced apoptosis of HL-60 cells, there’s a change of intracellular calcium distribution, moving from cytoplast especially Golgi’s apparatus to nucleus and accumulating there with the highest concentration. We report here that caspase-3.becomes activated in HT-induced apoptosis of HL-60 cells, which can be inhibited by overexpression of Bcl-2.protein. No sign of apoptosis or intracellular calcium movement from Golgi’s apparatus to nucleus in HL-60 cells overexpressing Bcl-2.or treated with Ac-DEVD-CHO, a specific inhibitor of caspase-3. The results indicate that activated caspase-3.can promote the movement of intracellular calcium from Golgi’s apparatus to nucleus, and the process is inhibited by Ac-DEVD-CHO (inhibitor of caspase-3., and that Bcl-2.can inhibit the movement and accumulation of intracellular calcium in nucleus through its inhibition on caspase3. Calcium relocalization in apoptosis seems to be irreversible, which is different from the intracellular calcium changes caused by growth factor.

关键词： Apoptosis calcium caspase-3 bcl-2 laser scanning confocal microscopy (LSCM).

On the basic cases for split G_2

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Chinese Science Bulletin 1997年第18期42卷 1512-1514页

作者： CHEN Zhonghu (CHENG Chon Hu)department of Mathematics, Xiangtan university, Xiangtan 411105, {2. department of Mathematics Xiangtan University Xiangtan China

LET G be a connected linear simple Lie group. Knapp and Speht showed that if P=MAN is a cuspidal parabolic subgroup of G, then there exists a unique basic case of M. The relations between the basic case of M and the unitary representations of G have also been discussed in ref. [1]. In ref. [2., Knapp gave a method for computing the basic case of M if M is a Levi factor of a maximal parabolic subgroup P=MAN of G when G is not the split G2./sub>. An expression of the basic case of M mentioned above has been given in ref. [2.. Boldoni-Silva and Knapp used this expression of the basic case of M to determine when the Langlands quotients J （MAN, σ, ν） are infinitesimally unitary under the conditions that P=MAN is maximal （i. e. dimA=1）, and that G is neither split F4 nor split G2. The result given in ref. [3. is important in the classification of the irreducible unitary representations of connected linear semisimple Lie groups.

关键词： split G2 maximal parabolic subgroups basic cases.