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Investigation on the choice of boundary conditions and shape functions for flexible multi-body system

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Acta Mechanica Sinica 2012年第1期28卷 180-189页

作者： ke-qi pan jin-yang liu School of Naval Architecture Ocean and Civil EngineeringShanghai Jiaotong University200240 ShanghaiChina

The objective of this investigation is to examine the correctness and efficiency of the choice of boundary conditions when using assumed mode approach to simulate flexible multi-body systems. The displacement field due to deformation is approximated by the Rayleigh-Ritz assumed modes in floating frame of reference （FFR） formulation. The deformations obtained by the absolute nodal coordinate （ANC） formulation which are transformed by two sets of reference coordinates are introduced as a criterion to verify the accuracy of the simulation results by using the FFR formulation. The relationship between the deformations obtained from different boundary conditions is revealed. Nu- merical simulation examples demonstrate that the assumed modes with cantilevered-free, simply-supported and free- free boundary conditions without inclusion of rigid body modes are suitable for simulation of flexible multi-body system with large over all motion, and the same physical deformation can be obtained using those mode functions, differ only by a coordinate transformation. It is also shown that when using mode shapes with statically indeterminate boundary conditions, significant error may occur. Furthermore, the slider crank mechanism with rigid crank is accurate enough for investigating boundary condition problem of flexible multi-body system, which cost significant less simulating time.

关键词： Multi-body systems. Boundary conditions - Assumed mode approach

Staged dendrite suppression for high safe and stable lithium-sulfur batteries

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Journal of Energy Chemistry 2025年第1期100卷 674-683页

作者： Jun Jiang Zhenjie Lu Yanwen Ding Shujun liu Zhijie qi Tian Tang Yunfan Zhang Zhiyuan Ma jingwen Sun Liang Xue Wenyao Zhang pan Xiong Xin Wang Junwu Zhu Yongsheng Fu key Laboratory for Soft Chemistry and Functional Materials of Ministry of Education Nanjing University of Science and Technology Jiangsu Pylon Battery Co.Ltd

The unavoidable dendrite growth and shuttle effect have long been stranglehold challenges limiting the safety and practicality of lithium-sulfur ***,we propose a dual-action strategy to address the lithium dendrite issue in stages by constructing a multifunctional surface-negatively-charged nanodiamond layer with high ductility and robust puncture resistance on polypropylene （PP） *** uniformly loaded compact negative layer can not only significantly enhance electron transmission efficiency and promote uniform lithium deposition,but also reduce the formation of dendrite during early deposition *** importantly,under the strong puncture stress encountered during the deterioration of lithium dendrite growth under limiting current,the high ductility and robust puncture resistance（145.88 MPa） of as-obtained nanodiamond layer can effectively prevent short circuits caused by unavoidable lithium *** Li||Li symmetrical cells assembled with nanodiamond layer modified PP demonstrated a stable cycle of over 1000 h at 2 mA cm-2with a polarization voltage of only 29.3 ***,the negative charged layer serves as a physical barrier blocking lithium polysulfide ions,effectively mitigating capacity *** improved cells achieved a capacity decay of only 0.042%per cycle after 700 cycles at 3 C,demonstrating effective suppression of dendrite growth and capacity attenuation,showing promising prospect.

关键词： Lithium-sulfur batteries Staged dendrite suppression Shuttle effect Surface-negatively-charged nanodiamond

A high precision computing method for heat transfer in the process of oil-water displacement

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Journal of Hydrodynamics 2021年第5期33卷 958-969页

作者： pan-pan Han ke Chen Dong-xi liu Yun-xiang You jin Wang State key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China Yazhou Bay Institute of Deepsea Technology Shanghai Jiao Tong UniversitySanya 572000China College of Ocean Science and Engineering Shanghai Maritime UniversityShanghai 201306China COTEC Offshore Engineering Solutions Beijing 100011China

The process of oil-water displacement is one of the key technologies in offshore underwater *** hot oil is contacting the normal-temperature water,the interfacial heat transfer should be investigated as the heat loss may result in wax precipitation and solidification which will reduce the flowing of oil and thus affect the *** for the numerical simulation of heat transfer,the calculation is costly as the underwater tank is usually large and the displacement period is long.A high precision computing method would greatly reduce the mesh ***,this research is performed to establish a high precision computing *** on volume of fluid(VOF),a new form of energy equation is *** equation is derived from temperature equation and the variable internal energy per volume is *** variable is additive and has a close relationship with volume *** algorithm implantation to OpenFOAM,two non-isothermal VOF solvers are established corresponding to temperature equation and the new equation *** an analytical solution is built,the two solvers are *** solver based on the new equation presents far more accurate results than the solver based on temperature *** energy weighted scheme is more reasonable than a linear temperature distribution for the mixture phase.

关键词： Multi-phase flow energy equation heat transfer oil-water displacement volume of fluid(VOF)

Biocompatibility and Cu ions release kinetics of copper-bearing titanium alloys

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Journal of Materials Science & Technology 2021年第36期95卷 237-248页

作者： Ling Ren Xiaohe Xu Hui liu ke yang Xun qi Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China Department of Ophthalmology Shengjing Hospital of China Medical University36 Sanhao StreetShenyang 110001China School of Materials Science and Engineering University of Science and Technology of China96 Jinzhai RoadHefei 230026China key Laboratory of Diagnostic Imaging and Interventional Radiology of Liaoning Province Department of RadiologyThe First Affiliated Hospital of China Medical University155 Nanjing Bei StreetShenyang 110001China

To reduce the risk of implant-associated infections,we previously designed and developed a series of medical copper(Cu)-bearing titanium alloys that release Cu ions and hence play an antibacterial ***,both excessive and deficient Cu levels adversely affect human health;therefore,the aim of the present study was to comprehensively evaluate the short-and long-term biosafety of Cu-bearing titanium alloys(Ti6 Al4V-Cu and Ti-Cu)both in vitro and in ***,the predominant kinetic mechanism of Cu ions release and its effect on biosafety were also *** results indicate that the biocompatibility of the Cu-bearing titanium alloys meets the requirements of ISO standards and the Cu ion release kinetics display a good correlation over the entire time period in the normal zero-order model with an almost constant release *** release rate maintained at a parts per billion level safe for humans;consequently,we can conclude that our Cu-bearing titanium alloys have satisfactory biocompatibility.

关键词： Cu ions Kinetic Biocompatibility Titanium

Einstein Probe discovery of EP240408a: A peculiar X-ray transient with an intermediate timescale

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 222-240页

作者： Wenda Zhang Weimin Yuan Zhixing Ling Yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati Lixin Dai jingwei Hu Shumei Jia Chichuan jin Dongyue Li Paul O’Brien Rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier Liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P.U.Fynbo Lluis Galbany Saurabh W.Jha Shuaiqing Jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong Li Bifang liu Mingjun liu Xing liu Yuan liu Zhu liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria Lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang qingwen Wu Xuefeng Wu Dong Xu Yanjun Xu Suijian Xue Yongquan Xue Zijian Zhang Zipei Zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang Jia Huo Zhenqing Jia Bowen Jiang Ge jin Chengkui Li Junfei Li Longhui Li Maoshun Li Wei Li Zhengda Li Tianying Lian Congzhan liu Heyang liu Huaqiu liu Fangjun Lu Laidan Luo Jia Ma Xuan Mao Haiwu pan Xin pan Liming Song Hui Sun Yunyin Tan qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang qinyu Wu Haitao Xu jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan Haonan yang Xiongtao yang Yanji yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu National Astronomical Observatories Chinese Academy of Sciences School of Astronomy and Space Sciences University of Chinese Academy of Sciences key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Institute of Space Sciences (ICE) CSIC Institut d’Estudis Espacials de Catalunya (IEEC) Max Planck Institute for Extraterrestrial Physics Innovation Academy for Microsatellites Chinese Academy of Sciences Department of Physics University of Hong Kong School of Physics and Astronomy University of Leicester School of Physics and Astronomy Sun Yat-sen University Department of Physics Anhui Normal University Shanghai Institute of Technical Physics Chinese Academy of Sciences Physics Department Tsinghua University Nevada Center for Astrophysics University of Nevada Las Vegas Department of Physics and Astronomy University of Nevada Las Vegas South African Astronomical Observatory Department of Astronomy University of Cape Town Department of Physics University of the Free State Université Paris Cité CNRS Astroparticule et Cosmologie Université Paris Cité CEA Paris-Saclay IRFU/DAp-AIM Department of Astronomy Guangzhou University Cosmic Dawn Center (DAWN) Niels Bohr Institute University of Copenhagen Department of Physics and Astronomy Rutgers the State University of New Jersey Institute for Cosmic Ray Research The University of Tokyo ESA/ESTEC Department of Astronomy School of Physics Huazhong University of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney Institute for Astronomy School of Physics The University of Sydney Department of Astronomy Xiamen University Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Department of Astronomy University of Science and Technology School of Astronomy and Space Sciences University of Science and Technology of China Institute of Deep Space Sciences Deep Space Exploration Laboratory Department of Astronomy School of Physics and Astronomy Yunnan University Shanghai Astronomical Observatory Chi

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe （EP） and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope （WXT） on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for *** flare reached a peak flux of 3.9×10-9erg cm-2s-1in 0.5-4 ke V,～300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 ke V,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for ～4 d,followed by a steep decay till becoming undetectable ～10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of～10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词： X-ray transients ${\bm~{Einstein~~Probe}}$

Sparse Representation Based Image Super-resolution Using Large Patches

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Chinese Journal of Electronics 2018年第4期27卷 813-820页

作者： liu Ning ZHOU pan liu Wenju ke Dengfeng National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Department of Electrical and Computer Engineering National University of Singapore

This paper addresses the problem of generating a high-resolution image from a low-resolution image. Many dictionary based methods have been proposed and have achieved great success in super resolution application. Most of these methods use small patches as dictionary atoms, and utilize a unified dictionary pair to conduct reconstruction for each patch, which may limit the super resolution performance. We use large patches instead of small ones to combine a dictionary and to conduct patch reconstruction. Since a large patch contains more meaningful information than a small one, the reconstruction result may have more high frequency details. To guarantee the completeness of the dictionary with large patch, the scale of the dictionary should be large as well. To handle the storage and calculation problems with large dictionaries,we adopt a binary encoding method. This method can preserve local information of patches. For each patch in the low-resolution image, we search its similar patches in the low-resolution dictionary to obtain a sub-dictionary. We compute its sparse representation to get the corresponding high-resolution version. Global reconstruction constraint is enforced to eliminate the discrepancy between the SR result and the ground truth. Experimental results demonstrate that our method outperforms other super resolution methods, especially when the magnification factor is large or the image is blurred by white Gaussian noise.

关键词： Super resolution Sparse representations Binary encoding

The d-orbital coupling modulation of CuNi alloy for acetonitrile electrochemical reduction and in-situ hydrogenation behavior characterization

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Science China Chemistry 2023年第11期66卷 3242-3251页

作者： Boling liu Dong He Zunjian ke Hongbo Wang Chongyang Tang qi Zhang Hang Xu Menghua yang Yafei yang qi liu Xiangheng Xiao School of Physics and Technology Wuhan UniversityWuhan 430072China Wuhan Research Center for Infectious Diseases and Cancer Chinese Academy of Medical SciencesWuhan 430072China Department of Physics City University of Hong KongHong Kong 999077China

Electrochemical reduction of acetonitrile to ethylamine with a high selectivity is a novel approach to manufacture valuable primary amines which are important raw material in organic chemical industry. However, the poor ethylamine Faradic efficiency(FE_(ethylamine)) and catalyst stability at the high current density prohibit this method from being practically used. Herein, CuNi alloy ultrafine-nano-particles based on the d-orbital coupling modulation were synthesized through the electrodeposition and their catalytic performance towards acetonitrile reduction reaction(ACNRR) has been systematically studied. The highest FE_(ethylamine)(97%) is achieved with the current density of-114 mA cm^(-2). For practical application, the current density can reach-602.8 mA cm^(-2) with 82.8% FE_(ethylamine)maintained. With the appearance of other organics which co-exist with acetonitrile in the SOHIO process, CuNi can also hydrogenate acetonitrile in it with more than 80% FE_(ethylamine). Our in-situ spectroscopy analysis and DFT calculations towards the acetonitrile hydrogenation behavior reveal that the evenly dispersed Ni in Cu modulates the dband so as to endow CuNi with the better acetonitrile adsorption, milder binding energy with the reaction intermediates, smaller barrier for *CH_3CH_2NH_2 desorption and higher ability for H_2O dissociation to provide *H.

关键词： CuNi alloy acetonitrile reduction reaction d-orbital coupling modulation in-situ spectroscopy analysis acetonitrile adsorption

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Facile and Convenient One-pot Synthesis of 1,1-Disubstituted Cyclopropanes in Water

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Chemical Research in Chinese Universities 2009年第1期25卷 37-39页

作者： liu Chun pan Wei yang yang WANG ke-wei DONG De-wen Chemistry and Biology College Beihua University Jilin 132013 P. R. China Department of Chemistry Northeast Normal University Changchun 130024 P. R. China

A facile and convenient one-pot synthesis method of substituted cyclopropanes in water has been developed. A series of 1,1-disubstituted cyclopropanes 3 were synthesized from the reaction of β-dicarbonyl compounds 1 with 1,2-dibromoethane 2, in very high yields catalyzed by tetrabutylammonium bromide（TBAB） at 50 ℃ in the presence of K2CO3 in water. The catalyst TBAB in the aqueous phase can be reused after the separation of organic products.

关键词： Cyclopropane β-Dicarbonyl compound Tetrabutylammonium bromide Water

Sedimentary Features and Paleogeographic Evolution of the Middle Permian Trough Basin in Zunyi,Guizhou,South China

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Journal of Earth Science 2023年第6期34卷 1803-1815页

作者： Zhichen liu qi Zhou ke liu yang Wang Deng Chen Yunming Chen Lin Xiao School of Resource and Environmental Engineering Guizhou UniversityGuiyang 550003China State key Laboratory of Biogeology and Environmental Geology School of Earth SciencesChina University of GeosciencesWuhan430074China 102 Geological Party Guizhou Bureau of Geology and Mineral Exploration and DevelopmentZunyi 563099China Innovation Center of Ore Resources Exploration Technology in the Region of Bedrock Ministry of Natural ResourcesGuiyang 550004China Guizhou Bureau of Geology and Mineral Exploration and Development Guiyang 550004China

Based on detailed field surveys,numerous sections and drillcores as well as analyses of lithofacies and sedimentary facies,sedimentary differentiation in the Middle Permian Zunyi(northern Guizhou,South China)trough basin was studied in *** by activities of the Emeishan mantle plume,the regional extensional setting and the extinguishing of carbonate production factories were shown from Guizhou to *** types of sedimentary enironments were developed in the study area:platform,slope,and *** this work,we established a sedimentary model for the study area,identified 14 syndepositional faults,and created the detailed reconstruction of the trough basin via a sedimentological *** is found that the paleogeographic evolution of the study area can be divided into six stages:(1)a pre-rifting stage,(2)rapid rifting and subsidence,(3)stable rifting and subsidence,(4)the second stage of rifting and subsidence,(5)silicification,and(6)regional uplift and *** sedimentary features and paleogeographic evolution of the Maokou Formation in Zunyi show that the platform,slope,and basin sedimentary features *** addition,the extensional setting and extinguishing of carbonate production factories were important preconditions for the evolution of the platform region in the study area,and the activity of syndepositional faults also played an important role in the paleogeographic evolution of this area.

关键词： Permian Maokou Period Zunyi Guizhou Province trough basin paleogeographic evo-lution sedimentary rocks deposits South China