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6篇 您的检索式:作者名="MA Dongjun"
    题名 作者 年代 出处 被引量
1A source term model of perturbation in a numerical study on flows around a slender body of revolution at a high angle of attack显示文摘A numerical study on flows around a slender body of revolution at a high angle of attack is conducted to investigate the influence of strength and circumferential angle of perturbation on flow asymmetry.A source term model is applied to simulate a real geometrical perturbation near the tip of the slender body.It can greatly facilitate the adjustment of perturbation strength.The results show that the bistable phenomenon does not appear any more at a small perturbation strength.For different perturbation strengths,the energy of the asymmetric perturbation flow experiences a similar spatial exponential growth regime with the same growth rate.The appearance of the bistable phenomenon is closely related to nonlinear saturation of the perturbation flow as perturbation strength increases.Yang Liu,Dongjun Ma,Dejun Sun~*,Xieyuan Yin Department of Modern Mechanics,University of Science and Technology of China,Hefei 230027,China 2009Progress in Natural Science:Materials International2009,19,12:2
2Instabilities and pattern evolution in a vertically heated annulus显示文摘The convection in an annular container with heated bottom,cooled top and insulated side walls are studied by both linear instability analysis and direct numerical simulation.The onset of convection is investigated by linear stability analysis and corresponding pattern selection mechanisms are discussed.The nonlinear evolution of different flow patterns and the convective heat transfer are simulated.The transition to oscillatory flow is also given by stability analysis where the base flow is a steady three dimensional flow.The stability predictions are in good agreement with the numerical simulations,including both the growth rate and the dimensionless frequency.WANG BoFu GUO ZhiWei MA DongJun SUN DeJun 2013Science China(Physics,Mechanics & Astronomy)2013,56,2:1
3Manipulating selenium molecular configuration in N/O dual-doped porous carbon for high performance potassium-ion storage显示文摘Potassium-selenium(K-Se)batteries have attracted more and more attention because of their high theoretical specific capacity and natural abundance of K resources.However,dissolution of polyselenides,large volume expansion during cycling and low utilization of Se remain great challenges,leading to poor rate capability and cycle life.Herein,N/O dual-doped carbon nanofibers with interconnected micro/mesopores(MMCFs)are designed as hosts to manipulate Se molecular configuration for advanced flexible K-Se batteries.The micropores play a role in confining small Se molecule(Se_(2–3)),which could inhibit the formation of polyselenides and work as physical barrier to stabilize the cycle performance.While the mesopores can confine long-chain Se(Se_(4–7)),promising sufficient Se loading and contributing to higher discharge voltage of the whole Se@MMCFs composite.The N/O co-doping and the 3D interpenetrating nanostructure improve electrical conductivity and keep the structure integrity after cycling.The obtained Se_(2–3)/Se_(4–7)@MMCFs electrode exhibits an unprecedented cycle life(395 mA h g^(−1) at 1 A g^(−1) after 2000 cycles)and high specific energy density(400 Wh kg^(−1),nearly twice the specific energy density of the Se_(2–3)@MMCFs).This study offers a rational design for the realization of a high energy density and long cycle life chalcogen cathode for energy storage.Dongjun Li Lifeng Wang Xiaolong Cheng Yu Yao Yu Jiang Pengcheng Shi Ying Wu Xiaojun Wu Cheng Ma Yan Yua 2021Journal of Energy Chemistry2021,30,11:1
4Numerical simulation of two-dimensional interface breakup显示文摘表面紧张的接口分开的二不能混合的液体的二维的混合层流动的非线性的进化数字地被模仿。液体方法的体积被用来捕获接口的运动。参量的研究被进行调查威伯数字,和密度比率的效果,碎过程上的等等。CAI Yong MA Dongjun SUN Dejun YIN Xieyuan 2006Progress in Natural Science:Materials International2006,16,5:0
5NUMERICAL STUDY OF TWO INTERFACE METHODS FOR COMPRESSIBLE MULTI-FLUID FLOWS显示文摘Two interface capturing methods are studied for multi fluid flows, governed by the stiffened gas equation of state. The mixture type interface capturing algorithm uses a simple volume fraction model Euler equations written in a quasi conservative form, which is solved by a standard high resolution piecewise parabolic method (PPM) with multi fluid Riemann solver. The level set interface capturing method uses a narrow band ghost fluid method (GFM) with no numerical smearing. Several examples are presented and compared for one and two dimensions, which show the feasibility of the two methods applied to various multi fluid problems.Ma Dongjun Cai Yong Sun Dejun Yin XieyuanDepartment of Modern Mechanics, University of Science and Technology of China,Hefei 230026,P.R.China 2001Transactions of Nanjing University of Aeronautics and Astronautics2001,18,z1:0
6A New Nonspherical Oxidation Model of Metal Particles显示文摘This paper analyzes the oxidation law of metal particles and proposes a new oxidation reaction rate model,based on measurements of thermogravimetric-mass spectrometer(TG-MS),X-ray diffractometer(XRD)and scanning electron microscope(SEM).The model is named EBM(egg broken model)with a formula of exponential law.According to the model,the aluminum particles do not react in a spherical shape,but crack and the melted metal inside flows out to form a new nonspherical surface and the reaction rate is still determined by the surface area.The model is verified with heating rates of 5℃/min,10℃/min and 25℃/min,and with particle size of 1–2μm,8–9μm and 20–22μm.Many models are based on spherical hypothesis and the new model gives a different physical illustration to explain oxidation progress of metal particles.The new model gives an exponential law,which fits the experimental data well,and it may be useful to understand oxidation mechanism of metal particles.ZHAO Weijie WANG Yan CUI Yanling WANG Baorui MA Dongjun WANG Yue 2023Journal of Thermal Science2023,32,2:0
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