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A Remark on the Cauchy Problem of 1D Compressible Navier-Stokes Equations with Density-dependent Viscosity Coefcients

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Acta Mathematicae Applicatae Sinica 2014年第1期30卷 193-204页

作者： Jin-tao WEI lin he Zhen-hua GUO Department of College Mathematics Teaching Longqiao College of Lanzhou Commercial College CNS and Department of Mathematics Northwest University

This paper is concerned with the Cauchy problems of one-dimensional compressible Navier-Stokes equations with density-dependent viscosity *** assumingρ0∈L1（R）,we will prove the existence of weak solutions to the Cauchy problems forθ〉*** will improve results in Jiu and Xin’s paper（***,1（2）：313–330（2008））in whichθ〉12is *** addition,We will study the large time asymptotic behavior of such weak solutions.

关键词： Cauchy problem compressible flows density-dependent viscosity Coefficients

First-principle study on the optical response of phosphorene

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Frontiers of physics 2015年第4期10卷 73-81页

作者： Jia-he lin Hong Zhang Xin-Lu Cheng College of Physical Science and Technology Sichuan University Chengdu 610065 China Key Laboratory of High Energy Density Physics and Technology of Ministry of Education Sichuan University Chengdu 610065 China

The optical response of phosphorene nanostructures was studied using time-dependent density func- tional theory （TDDFT）. Compared with the absorption spectrum of graphene, that of the phospho- rene nanostructure exhibits high absorbance in the ultraviolet region, which indicates a high light absorptivity. In a low-energy resonance zone, a spectral band extends to the entire near-infrared re- gions. When the impulse excitation polarizes in the armchair-edge direction, the low-energy plaslnon in a few-layer phosphorene nanostructure shows an apparent long-range charge-transfer excitation but is significantly less pronounced along the zigzag-edge direction. The edge configuration signifi- cantly affects the absorption spectrum of monolayer phosphorene nanostructures. The armchair-edge and the zigzag-edge serve different functions in the absorption spectrum. Moreover, the absorption spectrum of the few-layer phosphorene nanostructure changes with the number of layers when the impulse excitation polarizes in the armchair-edge direction. In addition, the change in tile low-energy resonance zone is significantly different from that in the high-energy resonance zone.

关键词： phosphorene nanostructures

Late Cenozoic Sedimentary Evolution of Pagri-Duoqing Co graben, Southern End of Yadong-Gulu Rift, Southern Tibet

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Acta Geologica Sinica(English Edition) 2018年第3期92卷 972-987页

作者： HA Guanghao WU Zhonghai he lin WANG Shubing Key Laboratory of Neotectonic Movement & Geohazards Ministry of Natural Resources Institute of Geomechanics Chinese Academy of Geological Sciences Beijing 100081 China Chinese Academy of Geological Sciences Beijing 10003 7 China College of Earth Science and Resources China University of Geosciences Beijing 100083 China

The north trending rifts in southern Tibet represent the E-W extension of the plateau and confirming the initial rifting age is key to the study of mechanics of these rifts. Pagri-Duoqing Co graben is located at southern end of Yadong-Gulu rift, where the late Cenozoic sediments is predominately composed of fluvio-lacustrine and moraine. Based on the sedimentary composition and structures, the fluviolacustrine could be divided into three facies, namely, lacustrine, lacustrine fan delta and alluvial fan. The presence of paleo-currents and conglomerate components and the provenance of the strata around the graben indicate that it was Tethys Himalaya and High Himalaya. Electron spin resonance(ESR) dating and paleo-magnetic dating suggest that the age of the strata ranges from ca. 1.2 Ma to ca. 8 Ma. Optically stimulated luminescence(OSL) dating showed that moraine in the graben mainly developed from around181-109 ka(late Middle Pleistocene). Combining previous data about the Late Cenozoic strata in other basins, it is suggested that 8-15 Ma may be the initial rifting time. Together with sediment distribution and drainage system, the sedimentary evolution of Pagri could be divided into four stages. The graben rifted at around 15-8 Ma due to the eastern graben-boundary fault resulting in the appearance of a *** by a geologically quiet period about 8-2.5 Ma, the paleolake expanded from east to west at around 8-6 Ma reaching its maximum at ca. 6 Ma. Then, the graben was broken at about 2.5 Ma. At last,the development of the glacier separated the graben into two parts that were Pagri and Duoqing Co since the later stages of the Middle Pleistocene. The evolution process suggested that the former three stages were related to the tectonic movement, which determined the basement of the graben, while the last stage may have been influenced by glacial activity caused by climate change.

关键词： north trending rifts initial rifting age Late Cenozoic strata sedimentary evolution OSL ESR and paleomagnetic dating Tibet China

Experiment and Simulation of Atmospheric Pressure Glow Surface Discharge

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Chinese Physics Letters 2003年第6期20卷 885-887页

作者： LIUMing-Hai GUCheng-lin PANYuan JIANGZhong-he HUXi-Wei CollegeofElectricalandElectronicEngineering HuazhongUniversityofScienceandTechnologyWuhan430074

Atmospheric pressure glow discharge was observed in a surface discharge generator. The frequency of ac power supply is more than 9kHz and the sinusoidal peak-to-peak applied voltage is 9kV. The electric field intensity in a kind of surface discharge generators is calculated with the boundary element method. Then a two-dimensional fluid model was used to simulate the ion trapping and electron trapping in a surface discharge just before the breakdown. The simulation results are in good agreement with our observation.

关键词： Atmospheric pressure

Practical method and application study for predicting cyclic accumulative deformations of the saturated soft clay

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Journal of Mountain Science 2017年第11期14卷 2348-2358页

作者： he lin-lin WANG Yuan-zhan LI Shu-zhao WANG Zhao-yang Key Laboratory of Hydraulic and Waterway Engineering of Ministry of Education Key Laboratory of regulation technology for inland waterway in transportation industry Chongqing Jiaotong University State Key Laboratory for Simulation & Safety of Hydraulic Engineering Tianjin Key Laboratory of Harbor & Ocean Engineering Tianjin University CNOOC Research Institute

The distribution of saturated soft clay is greatly wide in China. The current main measures adopted to deal with soft soil foundations may lead to environmental pollution, even some engineering accidents may happen on soft soil foundations. In order to solve engineering problems of saturated soft soil foundations well, researches of mechanical properties of them are necessary. One of the most important mechanical characteristics of saturated soft clay is its cyclic accumulative deformation under cyclic loadings. For saturated soft clay, the cyclic accumulative deformation is similar to the creep behavior under static loadings. Therefore, the cyclic accumulative deformation is equivalent to the creep, the number of loading cycles is seen as the time, and this study develops a practical method for predicting the cyclic accumulative deformation of saturated soft clay with the creep theory. The method is a pseudostatic elasto-plastic finite element method implemented by ABAQUS software. A fitted equation between cyclic accumulative strain and number of loading cycles and the empirical relationship of parameters of fitted equation were established with aseries of cyclic triaxial compression tests. Then with this empirical relationship of parameters, the method developed by this study was employed to predict the cyclic accumulative deformation under cyclic triaxial tension tests. Predicted results were in good agreement with test results, and the effectiveness of this method was thus validated for different stress states. The method was then applied in analyzing the cyclic accumulative deformation for soft soil foundation of a pile-supported wharf structure.

关键词： Saturated soft clay Finite elementmethod Soil tests Cyclic accumulativedeformation Creep theory

Quantum Theory of the Two-Photon Mazer: General Theory and Emission Probability

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Chinese Physics Letters 1999年第1期16卷 26-28页

作者： ZHANG Zhi-ming he lin-sheng Department of Applied Physics Shanghai Jiaotong UniversityShanghai 200030 Laser Spectroscopy Laboratory Anhui Institute of Optics and Fine MechanicsChinese Academy of SciencesHefei 230031

The idea of the two-photon mazer(microwave amplification via z-motion-induced emission of radiation)is put *** dressed states for the interaction of a cascade three-level atom with a quantum cavity field are *** general quantum theory of the two-photon mazer is established and its emission probability is *** effects of the atomic *** and of the atom-field detuning are *** is found that the two-photon mazer shows new features that differ from both the one-photon mazer and the conventional two-photon micromaser.

关键词： quantum Probability photon

Life Prediction Based on Transient Dynamics Analysis of Van Semi-trailer with Air Suspension System

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Chinese Journal of Mechanical Engineering 2011年第3期24卷 372-379页

作者： LI Liang SONG Jian he lin ZHANG Mengjun LI Hongzhi State Key Laboratory of Automotive Safety and Energy Tsinghua University Beijing 100084 China

The early fatigue damage in the van-body of the semi-trailer is often caused by the unique mechanical characteristics and the dynamic impact of the *** traditional finite element method with static strength analysis cannot support the fatigue design of van-body;thus,the dynamics analysis should be adopted for the endurance *** accurate dynamics model to describe the transient impacts of all kinds of uneven road and the proper system transfer functions to calculate the load transfer effects from tire to van-body are two critical factors for transient dynamics *** order to evaluate the dynamic performance,the dynamics model of the trailer with the air suspension is brought *** the analysis method of the power spectral density （PSD） is set up to study the transient responses of the road dynamic *** transient responses transferred from axles to van-body are calculated,such as dynamic stress,dynamic RMS acceleration,and dynamic load *** on the above dynamic responses,the fatigue life of van-body is predicted with the finite element analysis （FEA） *** the test parameters of the trailer with air suspension,the simulation system with Matlab/Simulink is constructed to describe the dynamic responses of the impacts of the tested PSD of the vehicle axles,and then the fatigue life is predicted with FEA *** simulated results show that the vibration level of the van-body with air suspension is reduced and the fatigue life is *** real vehicle tests on different roads are carried out,and the test results validate the accuracy of the simulation *** proposed fatigue life prediction method is effective for the virtual design of auto-body.

关键词： van-body air suspension system transient dynamics power spectral density (PSD) life prediction

Effect of inclusion size on the high cycle fatigue strength and failure mode of a high V alloyed powder metallurgy tool steel

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International Journal of Minerals,Metallurgy and Materials 2012年第7期19卷 608-614页

作者： Jun Yao Xuan-hui Qu Xin-bo he lin Zhang State Key Laboratory for Advanced Metals and Materials School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083China

The fatigue strength of a high V alloyed powder metallurgy tool steel with two different inclusion size levels, tempered at different temperatures, was investigated by a series of high cycle fatigue tests. It was shown that brittle inclusions with large sizes above 30μm prompted the occurrence of subsurface crack initiation and the reduction in fatigue strength. The fracture toughness and the stress amplitude both exerted a significant influence on the fish-eye size. A larger fish-eye area would form in the sample with a higher fracture toughness subjected to a lower stress amplitude. The stress intensity factor of the inclusion was found to lie above a typical value of the threshold stress intensity factor of 4 MPa.m^1/2. The fracture toughness of the sample with a hardness above HRC 56 could be estimated by the mean value of the stress intensity factor of the fish-eye. According to fractographic evaluation, the critical inclusion size can be calculated by linear fracture mechanics.

关键词： powder metallurgy tool steel fatigue of materials strength of materials failure modes inclusions fractography

Real-time Tire Parameters Observer for Vehicle Dynamics Stability Control

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Chinese Journal of Mechanical Engineering 2010年第5期23卷 620-626页

作者： LI Liang LI Hongzhi ZHANG Xiaolong he lin SONG Jian State Key Laboratory of Automotive Safety and Energy Tsinghua University Beijing 100084 China

The performance of the vehicle dynamics stability control system（DSC） is dominated by the accurate estimation of tire forces in *** characteristics of tire forces are determined by tire dynamic states and parameters,which vary in an obviously large scope along with different working ***,there have been many methods based on the nonlinear observer to estimate the tire force and dynamic parameters,but they were only used in off-line analysis because of the computation complexity and the dynamics differences of four tires in the steering maneuver conditions were not considered *** paper develops a novel algorithm to observe tire parameters in real-time controller for *** algorithm is based on the sensor-fusion technology with the signals of DSC sensors,and the tire parameters are estimated during a set of maneuver *** calibrated tire parameters in the control cycle are treated as the elementary states for vehicle dynamics observation,in which the errors between the calculated and the measured vehicle dynamics are used as the correcting factors for the tire parameter observing *** test process with a given acceleration following a straight line is used to validate the estimation method of the longitudinal stiffness;while the test process with a given steering angle is used to validate the estimated value of the cornering *** ground test result shows that the proposed algorithm can estimate the tire stiffness accurately with an acceptable computation cost for real-time controller only using DSC sensor *** proposed algorithm can be an efficient algorithm for estimating the tire dynamic parameters in vehicle dynamics stability control system,and can be used to improve the robustness of the DSC controller.

关键词： tire longitudinal stiffness cornering stiffness vehicle dynamics stability