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Analytical and numerical studies on a single-droplet evaporation and combustion under forced convection

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Acta Mechanica Sinica 2015年第4期31卷 523-530页

作者： L.X.Zhou k.li Department of Engineering Mechanics Tsinghua University

Existing droplet evaporation/combustion mod- els in computational fluid dynamics （CFD） simulation of spray combustion are based on simplified 1-D models. Both these models and recently developed 3-D models of single- droplet combustion do not give the conditions for the different existing droplet combustion modes. In this paper, droplet evaporation and combustion are studied both analytically and numerically. In the analytical solution, a 2-D axisymmetric flow surrounding an evaporating and combusting droplet was considered. The governing equations were solved using an integral method, similar to the karman-Pohlhausen method for solving boundary-layer flows with pressure gradient. The results give a local evaporation rate and flame radius in agree- ment with experimental results. In numerical simulation, 3-D combusting gas flows surrounding an ethanol droplet were studied. The prediction results show three modes of droplet combustion under different relative velocities, explaining the change in the evaporation constant with an increase in relative velocity observed in experiments. This implies that different droplet combustion models should be developed in simu- lating spray combustion. The predicted local evaporation rate and flame radius by numerical simulation are in agree- ment with the analytical solution in the range of azimuthal angles 0° 〈 θ 〈 90°. The numerical results indicate that the drag force of an evaporating and combusting droplet is much smaller than that of a cold solid particle, and thus the currently used drag models should be modified.

关键词： Droplet evaporation and combustion Dropletcombustion modes Numerical simulation

Effect of arc sprayed coatings on tensile properties of a type 316 steel

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中国有色金属学会会刊：英文版 2004年第z1期14卷 95-99页

作者： liU Gui-min MA li-li k.J.kurzydlowski Faculty of Materials Science and Engineering Academy of Armored Force EngineeringBeijing 100072 China Faculty of Materials Science and Engineering Academy of Armored Force EngineeringBeijing 100072 China Faculty of Materials Science and Engineering Warsaw University of Technology Warsaw Poland

The effect of Al- and AlSiRE-coatings obtained by arc spray (AS) and high velocity arc spray (HVAS) technologies, on the tensile properties of type 316 steel specimens strained at elevated temperatures in air and vacuum has been systematically investigated. It is found that both temperature and environment play an important role in determining the mechanical properties of the coated 316 steel specimens strained at elevated temperatures. And the quantitative changes of surface roughness of coatings before and after straining correspond to the mechanical properties of the 316 steel substrate.

关键词： type 316 steel arc spray high velocity arc spray coating tensile property

Performance　Analysis　of　Slotted　Multichannel　ALOHA　Systems　with　Capture　in　Microcellular　Environments

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通信学报 1995年第4期16卷 24-34页

作者： XiaoxinQiu VictorO.k.li UniversityofSouthernCalifornia LosAngelesCA90089－2565U.S.A UniversityofSouthernCalifornia LosAngele

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ＰｅｒｆｏｒｍａｎｃｅＡｎａｌｙｓｉｓｏｆＳｌｏｔｔｅｄＭｕｌｔｉｃｈａｎｎｅｌＡＬＯＨＡＳｙｓｔｅｍｓｗｉｔｈＣａｐｔｕｒｅｉｎＭｉｃｒｏｃｅｌｌｕｌａｒＥｎｖｉｒｏｎｍｅｎｔｓＸｉａｏｘｉｎＱｉｕ；ＶｉｃｔｏｒＯ．Ｋ．Ｌｉ（Ｕｎｉｖｅｒｓｉｔｙｏ...

关键词：多信道阿罗哈网协议通过量无线通信蜂窝

Mobile augmented reality visualization and collaboration techniques for on-site finite element structural analysis

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International Journal of Modeling, Simulation, and Scientific Computing 2018年第3期9卷 2-21页

作者： W.k.li A.Y.C.Nee S.k.Ong NUS Graduate School for Integrative Sciences and Engineering National University of Singapore 28 Medical Drive Singapore 117456Singapore Mechanical Engineering Department National University of Singapore 9 Engineering Drive 1 Singapore 117576Singapore∗mpeneeyc@nus.edu.sg

In this paper,a mobile augmented reality(AR)framework for on-site finite element analysis(FEA)is *** proposed framework is achieved using a client–server *** performance of FEA relies on several important components,namely,computational power,visualization technique,and numerical *** renders intuitive computer-generated contents directly on a user’s *** FEA with AR helps users through enhancing their perception and interaction with the engineering *** and effective visualization of these data using an AR platform can reduce the misinterpretation in spatial and logical *** the past decade,AR has undergone a transition from desktop to phablet *** platforms enable user exploration of FEA results in *** client side uses a hybrid method to visualize FEA results in the mobile AR *** addition,a user can collaborate with other users by using the result sharing function.A prototype with basic functions has been built and a case study has been implemented to demonstrate the visualization method and evaluate the overall performance.

关键词： Augmented reality scientific visualization on-site finite element analysis client-server.

PROPERTIES OF THREE-DIMENSIONAL MOVEMENT OF SANDY WATER DISCHARGED INTO A LAkE

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Journal of Hydrodynamics 2001年第2期13卷 72-76页

作者： Deng, Y. li, J. li, k.F. Zhao, W.Q. State key Lab. of High Speed Flow Sichuan Univ. Chengdu 610065 China

A Random Trajectory Model (RTM) for solid-liquid two-phase flow based on the Lagrangian Method is presented in this paper. The effects of water drag force, pressure gradient force, buoyancy and virtual mass force on the particles were included and the turbulent dispersion was modeled by random method. Three-dimensional k-Ε model was used to calculate the flow field. A pumped-storage power station, with a natural lake as its upper pool, was taken as a case for the study. Averaged movement trajectories, velocities and the volume-concentration distributions for 5 groups of sediment particles, were predicted with RTM. The possible silted locations in the lake were also predicted.

关键词： Boundary conditions Computer simulation Lakes Sand Three dimensional Two phase flow Velocity

Activation of human fibroblast-like synoviocytes by uric acid crystals in rheumatoid arthritis

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Cellular & Molecular Immunology 2011年第6期8卷 469-478页

作者： Da P Chen Chun k Wong Lai S Tam Edmund k li Christopher Wk Lam Department of Chemical Pathology The Chinese University of Hong KongPrince of Wales HospitalShatinNTHong KongChina Department of Clinical Laboratory Children’s Hospital of Chongqing Medical UniversityChongqingChina Department of Medicine and Therapeutics The Chinese University of Hong KongPrince of Wales HospitalNgan Shing StreetShatinNTHong KongChina Macao Institute for Applied Research in Medicine and Health Macao University of Science and TechnologyAvenida Wai LongTaipaMacaoChina

Hyperuricemia-mediated uric acid crystal formation may cause joint inflammation and provoke the destruction of joints through the activation of inflammasome-mediated innate immune ***,the immunopathological effects and underlying intracellular regulatory mechanisms of uric acid crystal-mediated activation of fibroblast-like synoviocytes(FLS)in rheumatoid arthritis(RA)have not been ***,we investigated the in vitro effects of monosodium urate crystals,alone or in combination with the inflammatory cytokines tumor-necrosis factor(TNF)-a or interleukin(IL)-1b,on the activation of human FLS from RA patients and normal control subjects and the underlying intracellular signaling mechanisms of treatment with these *** urate crystals were able to significantly increase the release of the inflammatory cytokine IL-6,the chemokine CXCL8 and the matrix metalloproteinase(MMP)-1 from both normal and RA-FLS(all P,0.05).Moreover,the additive or synergistic effect on the release of IL-6,CXCL8 and MMP-1 from both normal and RA-FLS was observed following the combined treatment with monosodium urate crystals and TNF-a or *** experiments showed that the release of the measured inflammatory cytokine,chemokine and MMP-1 stimulated by monosodium urate crystals were differentially regulated by the intracellular activation of extracellular signal-regulated kinase and c-Jun N-terminal kinase pathways but not the p38 mitogen-activated protein kinase *** results therefore provide a new insight into the uric acid crystal-activated immunopathological mechanisms mediated by distinct intracellular signal transduction pathways leading to joint inflammation in RA.

关键词： cytokines fibroblast-like synoviocytes rheumatoid arthritis signal transduction uric acid

THERMOSTABIliTY OF liCu₂O₂ AND liCu₃O₃

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Chinese Chemical Letters 1996年第2期7卷 195-198页

作者： lin, JH li, k Ruan, Sk Su, MZ Schweda, E BEIJING UNIV DEPT CHEM MATBEIJING 100871PEOPLES R CHINA UNIV TUBINGEN INST ANORGAN CHEMD-72076 TUBINGENGERMANY

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ＴＨＥＲＭＯＳＴＡＢＩＬＩＴＹＯＦＬｉＣｕ２Ｏ２ＡＮＤＬｉＣｕ３Ｏ３￥ＪｉａｎＨｕａＬＩＮ；ＫａｉＬＩ；ＳｈｅｎＫａｎｇＲＵＡＮａｎｄＭｉａｕＺｅｎｇＳＵ(ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＣｈｅｍｉｓｔｒｙ，ＰｅｋｉｎｇＵｎｉｖｅｒｓｉ...

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Fuzzy　Logic　Based　Adaptive　Control　of　Constrained　Flexible-link　Robot

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Systems Science and Systems Engineering 1997年第3期7卷 92-101页

作者： WANG li li C.k. Department of Automation South China University of TechnologyGuangzhou 510641 Department of Electronic Engineering Hong Kong Polytechnic University Hong Kong

In this paper, a novel adaptive fuzzy control scheme is presented . The controller is constructed by using a table lookup scheme and self tuning techniques, which includes the identification block, the fuzzification, the updating rule base, the defuzzification, and the crisp controller (sub controller), etc. The adaptive fuzzy controller is designed in detail by means of triangular membership function and the center of gravity method. The control scheme addressed here is implemented to control the motion of the end effector of a two link constrained flexible manipulator. Computer simulation results show that the novel adaptive fuzzy control scheme works quite well.

关键词： adaptive control fuzzy logic self tuning constrained motion flexible link manipulator.

Nanoscale deformation of multiaxially forged ultrafine-grained Mg-2Zn-2Gd alloy with high strength-high ductility combination and comparison with the coarse-grained counterpart

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Journal of Materials Science & Technology 2018年第2期34卷 311-316页

作者： k. li V.S.Y.Injeti P. Trivedi L.E. Murr R.D.k. Misra Department of Metallurgical Materials and Biomedical Engineering University of Texas at El Paso 500 W. University Avenue El Paso TX 79968-0521 USA

Cold processing of magnesium （Mg） alloys is a challenge because Mg has a hexagonal close-packed （HCP） lattice with limited slip systems, which makes it difficult to plastically deform at low temperature. To address this challenge, a combination of annealing of as-cast alloy and multi-axial forging was adopted ro obtain isotropic ultrafine-grained （UFG） structure in a lean Mg-2Zn-2Gd alloy with high strength （yield strength： ~227 MPa）-high ductility （% elongation：～30%） combination. This combination of strength and ductility is excellent for the lean alloy, enabling an understanding of deformation processes in a formable high strength Mg-rare earth alloy. The nanoscale deformation behavior was studied via nanoindentation and electron microscopy, and the behavior was compared with its low strength （yield strength：～46 MPa） - low ductility （% elongation：～7%） coarse-grained （CG） counterpart. In the UFG alloy, extensive dislocation slip was an active deformation mechanism, while in the CG alloy, mechanical twinning occurred. The differences in the deformation mechanisms of UFG and CG alloys were reflected in the discrete burst in the load-displacement plots. The deformation of Mg-2Zn-2Gd alloys was significantly influenced by the grain structure, such that there was change in the deformation mechanism from dislocation slip （non-basal slip） to nanoscale twins in the CG structure. The high plasticity ofUFG Mg alloy involved high dislocation activity and change in activation volume.

关键词： Magnesium alloy Ultrafine-grained Nanoscale deformation