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Microstructural and deformational studies on mylonite in the detachment faults of Yalashangbo dome, North Himalayan domes zone

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Progress in Natural Science:Materials International 2005年第11期15卷 1005-1013页

作者： ZHANG Bo, ZHANG Jinjiang, GUO Lei and WANG Weiliang (Department of Geology, school of Earth and Space sciences, peking university, beijing 100871, china) Department of Geology School of Earth and Space Sciences Peking University Beijing 100871 China

The Yalashangbo dome, located at the eastern end of North Himalayan domes zone, has a geometry and structure similar to those of a metamorphic core complex. Ductile shear zones formed the detachment system around the dome and these zones are composed of garnet-bearing phyllonite, mylonitic schist, mylonitic gneiss and mylonitic granite. Ductile shear fabrics developed well in my-lonitic rocks, and penetrative lineation and foliation were formed by stretched quartz and feldspar and preferred orientation of mica. Polar Mohr diagram method is used to calculate the kinematic vorticity numbers of the shear zones in the detachment system. Results indicate that the shear zone is a thinned shear zone (thinning of 23 % ) in an extensional setting which underwent a general shear dominated by simple shear. Comparison of the vorticity numbers between the northern and southern flanks of the Yalashangbo dome shows that the dome is an asymmetric system formed by a north-northwest-directed detaching unanimously. Statistical fractal analysis shows that the shapes of dynamically recrystallized quartz grains in the mylonites have characteristics of self-similarity, with fractal numbers ranging from 1.05 to 1.18. From these fractal numbers, the strain rate of the rock was deduced from 10-9.2S-1 to 10-7.3S-1, the differential paleao-stress was 13.7-25.6 MPa during the deformation happened at a temperature over 500 ℃. The ductile shear zones in the detachment system around Yalashangbo dome were formed under a high green-schist grade condition or happened simultaneously with the intrusion of granite.

关键词： Yalashangbo dome ductile shear zone kinematic vorticity fractal analysis deformation temperature strain rate.

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Convergence rates for reversible Markov chains without the assumption of nonnegative definite matrices

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Science china mathematics 2010年第8期53卷 1979-1988页

作者： MAO Yong-Hua school of mathematical sciences,beijing Normal university,Laboratory of mathematics and Complex Systems,Ministry of Education,beijing 100875,china school of mathematical sciences Beijing Normal University Laboratory of Mathematics and Complex Systems Ministry of Education

Explicit convergence rates in geometric and strong ergodicity for denumerable discrete time Markov chains with general reversible transition matrices are obtained in terms of the geometric moments or uniform moments of the hitting times to a fixed *** way by Lyapunov's drift conditions is also used to derive these convergence *** a typical example,the discrete time birth-death process(random walk) is studied and the explicit criteria for geometric ergodicity are presented.

关键词： Markov chain spectral theory convergence rate geometric ergodicity strong ergodicity Lyapunov’s condition

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CONTACT PROCESS ON HEXAGONAL LATTICE

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Acta Mathematica Scientia 2010年第3期30卷 769-790页

作者：姚强李群昌 Department of Statistics and Actuarial Science School of Finance and Statistics East China Normal University school of mathematical sciences Peking University

In this article, we discuss several properties of the basic contact process on hexagonal lattice H, showing that it behaves quite similar to the process on d-dimensional lattice Zd in many aspects. Firstly, we construct a coupling between the contact process on hexagonal lattice and the oriented percolation, and prove an equivalent finite space-time condition for the survival of the process. Secondly, we show the complete convergence theorem and the polynomial growth hold for the contact process on hexagonal lattice. Finally, we prove exponential bounds in the supercritical case and exponential decay rates in the subcritical case of the process.

关键词： Hexagonal lattice contact process critical value complete convergence theorem rate of growth

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RECOGNITION AND CLASSIFICATION FOR O(n)-EQUIVARIANT BIFURCATIONS WITH O(n)-CODIMENSION LESS THAN 5

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Chinese Annals of mathematics,Series B 1998年第4期19卷 391-400页

作者： WANG XIAOFENG (Department of Applied mathematics, Tsinghua university, beijing 100084, china.)TANG YUN (Department of Applied mathematics, Tsinghua university, beijing 100084, china.)WANG DUO (school of mathematical Science, peking universityl Beliing 10 Department of Applied mathematics Tsinghua University Beijing 100084 China school of mathematical Science Peking University Beijing 100080 China

Bifurcation problems equivariant under the standard action of the orthogonal group O(n) up to O(n)-codimension 4 are classified into 19 classes. For each class the normal form and one universal unfolding are calculate... 详细信息

关键词： O(n)-equivariant bifurcation Normal form Universal unfolding Recognition problem

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ARC-TRANSITIVE CUBIC GRAPHS OF ORDER 4_p

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Chinese Annals of mathematics,Series B 2004年第4期25卷 545-554页

作者： XUMINGYAO ZHANGQINHAI ZHOUJINXIN schoolofmathematicsandComputersciences ShanxiTeachersUniversityLinfen041004ShanxiChina schoolofmathematicsandComputersciences ShanxiTeachersUniversityLinfen041004ShanxiChina.

In this paper, a complete classification of arc-transitive cubic graphs of order 4p is given.

关键词： Arc-transitive graph Cubic s-regular graph Coverings of a graph

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Petrogenesis and significance of the Hongshan syenitic pluton,South Taihang: zircon SHRIMP U-Pb age, chemical compositions and Sr-Nd isotopes

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Progress in Natural Science:Materials International 2006年第2期16卷 192-200页

作者： ZHOU Ling and CHEN Bin (Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, school of Earth and Space sciences, peking university, beijing 100871, china) Key Laboratory of Orogenic Belts and Crustal Evolution MOE School of Earth and Space Sciences Peking University Beijing 100871 China

The Hongshan syenitic pluton (South Taihang) is mainly made up of hornblende syenite and minor granite. SHRIMP zircon dating yields a U-Pb age of 135±2.7 Ma for the emplacement of the pluton, while biotite Rb-Sr isotopic data give an isochron of 120. 3±2.4 Ma. Hongshan syenites show low silica, high alkalis and LILE such as Sr, and exhibit negligible Eu anomalies or slightly positive anomalies in the REE patterns. The syenites show quite enriched isotopic compositions with Isr from 0.7052 to 0. 7102 and εNd(t) from -7.5 to - 11.1. Petrogenesis of the pluton can be that partial melting of an enriched lithospheric mantle gave birth to an alkali basaltic magma, which subsequently underplated in the lower crust and experienced a coupled fractionation of ferromagnesian phases like pyroxene and hornblende and minor ( china Plateau" in the Mesozoic.

关键词： syenite zircon SHRIMP Nd-Sr isotopes Taihang North china craton.

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Perfect reconstruction image modulation based on BEMD and quaternionic analytic signals

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Science china(Information sciences) 2011年第12期54卷 2622-2634页

作者： qiao LiHong 1 , NIU KaiFu 2 , WANG Ning 2 & PENG LiZhong 2 1 College of Information Science and Engineering, Henan university of Technology, Zhengzhou 450001, china 2 school of mathematical sciences, peking university, beijing 100871, china College of Information Science and Engineering Henan University of Technology school of mathematical sciences Peking University

Image modulation represents image by meaningful characters such as image instantaneous amplitude and instantaneous frequency. A perfect reconstruction image modulation method is proposed. In detail, the bidimensional empirical mode decomposition (BEMD) is first improved to adaptively decompose image into monocomponents. Then by the quaternionic analytic method, suitable analytic signals is acquired. A new polar form is further proposed to modulate images, then seven characters are derived including instantaneous amplitude and instantaneous frequencies. We demonstrate the techniques on both synthetic and natural images, depict the needle program of the estimated frequencies and obtain the reconstructions that are the same with the original images. The applications in image segmentation and separation establish the validity of characterizing images of this type as sums of locally narrow band modulated components.

关键词： perfect reconstruction image modulation AM-FM representation BEMD quaternionic analytic signals

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Kinetic characteristics of continuous flow polymerase chain reaction chip: A numerical investigation

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Science china(Technological sciences) 2010年第7期53卷 1967-1972页

作者： WANG ShiYing1 & WANG Wei2,3 1 school of Physics, peking university, beijing 100871, china 2 Institute of Microelectronics, peking university, beijing 100871, china 3 National Key Laboratory of Science and Technology on Micro/Nano Fabrication, beijing 100871, china school of Physics Peking University Beijing China Institute of Microelectronics Peking University Beijing China National Key Laboratory of Science and Technology on Micro/Nano Fabrication Beijing China

Continuous flow PCR (polymerase chain reaction) chip holds impressive advantages compared to micro chamber PCR chip. In order to have better understanding of kinetic characteristics of continuous flow PCR chip, a comprehensive mathematical model is presented in this paper, including melting, annealing and extension phases of a typical PCR process which has the essence of a convection-diffusion-reaction system. Using this model, we can simulate the PCR process in series of reaction cycles. Numerical results show that the average sample velocity plays a significant role in affecting the amplification efficiency. Also, appropriate combination of the PCR mixture is important for high-quality DNA amplification. Giving a large initial DNA concentration range, the continuous flow PCR scheme holds excellent real-time detection ability theoretically. The present numerical model bridges the temperature distribution to the real DNA amplification, and thereby is able to successfully predict continuous flow PCR properties which are important for the chip design.

关键词： continuous flow PCR chip numerical simulation convection-diffusion-reaction system

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Signal propagations and linkages of subsurface temperature anomalies in the tropical Pacific and Indian Ocean

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Progress in Natural Science:Materials International 2005年第9期15卷 804-809页

作者： QIAN Weihong** and HU Haoran(Monsoon & Environment Research Group, school of Physics, peking university, beijing 100871, china) Monsoon & Environment Research Group School of Physics Peking University Beijing 100871 China

The propagation characteristics of signals along different zonal-time profiles are analyzed using surface and subsurface temperature anomalies over the tropical Pacific and Indian oceans. Analyses show that there are intrinsic relationships between El Nio events in the eastern equatorial Pacific and dipole events in the equatorial Indian Ocean. In the region of tropical North Pacific between the equator and 16°N, there is a circle of propagation of subsurface temperature anomalies. El Nio events only happen when the warm subsurface signals reach the eastern equatorial Pacific. Dipole events are characterized when a warm subsurface signal travels along off-equatorial Indian Ocean to the western boundary. From these analyses, we believe that subsurface temperature anomalies can be considered to be the oceanographic early signal to forecast El Nio events in Pacific Ocean and dipole events in Indian Ocean, respectively.

关键词： El Nio event dipole event subsurface sea temperature early signal.

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Recent developments and some open problems in Finsler geometry

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Chinese Science Bulletin 2001年第13期46卷 1059-1061页

作者： MO Xiaohuan & SHEN Zhongmin1. school of mathematical sciences, peking university, beijing 100871, china 2. Department of mathematics, IUPUI 402 N. Blackford Street, Indianapolis, IN 46202-3216, USA school of mathematical sciences Peking University Beijing China Department of mathematics IUPUI Indianapolis USA

Finsler geometry is just Riemannian geometry without the quadratic restriction. Recent studies on Finsler geometry have taken on a new look. In this article, we will briefly discuss recent developments and some open p... 详细信息

关键词： Finsler geometry open problems recent development.

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