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A particle-resolved heat-particle-fluid coupling model by DEM-IMB-LBM

Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2267-2281页

作者： Ming Xia Jinlong fu y.T.Feng Fengqiang Gong Jin yu Hunan key Laboratory of Geomechanics and Engineering Safety Xiangtan UniversityXiangtan411105China Zienkiewicz Institute for Modelling Data and AISwansea UniversitySwanseaSA18EPUK School of Civil Engineering Southeast UniversityNanjing211189China fujian Research Center for Tunneling and Urban Underground Space Engineering Huaqiao UniversityXiamen361021China

Multifield coupling is frequently encountered and also an active area of research in geotechnical *** this work,a particle-resolved direct numerical simulation(PR-DNS)technique is extended to simulate particle-fluid interaction problems involving heat transfer at the grain *** this extended technique,an immersed moving boundary(IMB)scheme is used to couple the discrete element method(DEM)and lattice Boltzmann method(LBM),while a recently proposed Dirichlet-type thermal boundary condition is also adapted to account for heat transfer between fluid phase and solid *** resulting DEM-IBM-LBM model is robust to simulate moving curved boundaries with constant temperature in thermal *** facilitate the understanding and implementation of this coupled model for non-isothermal problems,a complete list is given for the conversion of relevant physical variables to lattice ***,benchmark tests,including a single-particle sedimentation and a two-particle drafting-kissing-tumbling(DkT)simulation with heat transfer,are carried out to validate the accuracy of our coupled *** further investigate the role of heat transfer in particle-laden flows,two multiple-particle problems with heat transfer are *** examples demonstrate that the proposed coupling model is a promising high-resolution approach for simulating the heat-particle-fluid coupling at the grain level.

关键词： Particle-fluid interaction Heat transfer Discrete element method(DEM) Lattice Boltzmann method(LBM) Dirichlet-type thermal boundary Direct numerical simulation

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Zero-Point Motions in Trans-Polyacetylene

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Chinese Physics Letters 1998年第9期15卷 674-676页

作者： fu Rong-tang RAO Xue-song SUN Xin y.kawazoe Department of Physics Fudan UniversityShanghai 2004331 Institute for Materials Research Tohoku UniversitySendai 980-77Japan

In order to substantiate the applicability of the Takayama-Lin-Liu-Maki model to conducting polymer,the Su-Schrieffer-Heeger model is generalized to include the effects of lattice zero-point motions on electronic *** the treatment of the white-noise approximation,some significant electronic properties of Peierls-Fröhlich states are *** finding shows that the correlation of lattice motions suppresses the effects of zero-point motions on the electronic properties more seriously.

关键词： properties lattice electronic

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STUDy ON NANOMETER ZINC PARTICLES FABRICATED By GAS EVAPORATION METHOD

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Acta Metallurgica Sinica(English Letters) 2003年第3期16卷 161-168页

作者： A.A.A.Saleh X.J.Zhai y.C.Zhai y.fu A.L.Zhang School of Materials and Metallurgy Northeastern UniversityShenyang110004ChinaSchool of Materials and MetallurgyNortheastern UniversityShenyang110004ChinaSchool of Materials and MetallurgyNortheastern UniversityShenyang110004ChinaSchool of Materials and MetallurgyNortheastern UniversityShenyang110004ChinaSchool of Materials and MetallurgyNortheastern UniversityShenyang110004China

Nanometer Zn particles with mean diameters 12-100nm made by evaporating its powders in argon gas were studied mainly by X-ray diffraction and electron microscopy. They are collected at various distances and those factors influencing the mean particle size were studied. The optimal synthetic conditions were obtained, i.e., evaporation temperature is 1200℃; argon flow rate is 0.4m3/h; amount of powder charged is 3g; distance from evaporation source is 10cm. It was found that the size of particles was governed by argon flow rate, evaporation temperature, amount of metal charged and distance from the source. The size increases remarkably with distance in the space where no metal vapor exists. This implies that the crystallites grow by coalescence. Electron micrographs and diffraction patterns are reproduced to show the size, shape and state of oxidations. Nanoparticles with definite crystal habits were sometimes observed among those with irregular ones.

关键词： gas evaporation method nanometer Zn XRD TEM

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NUMERICAL SIMULATION OF COLUMNAR TO EQUIAXED TRANSITION FOR DIRECTIONALLy SOLIDIFIED Ti-44Al ALLOy

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Acta Metallurgica Sinica(English Letters) 2008年第2期21卷 146-156页

作者： k.F. Wang J.J. Guo G.F. Mi C. y. Li H.Z. fu School of IVlaterials Science and Engineering Henan Polytechnic University Jiaozuo 454100 China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

Solute diffusion controlled solidification model was applied to simulate the columnar to equiaxed transition （CET） during directional solidification of Ti-44Al alloy. The simulation results show that the solutal interactions from growing equiaxed grains play an important role on CET. The effects of the applied thermal gradient and pulling velocity, the equiaxed seed spacing and nucleation undercooling on the CET are investigated in the present simulation. The simulated results indicated that the columnar branch spacing depends not only on the thermal gradient and the pulling velocity, but also on number of the seeds. A spacing adjustment can occur through initiation of seeds that develop into new columnar grains. The dependence of the CET on the thermal gradient and pulling velocity, qualitatively agrees with the analytical CET model of Hunt,

关键词： Ti-44Al alloy Directional solidification columnar to equiaxedtransition (CET) Numerical simulation

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16.3%Efficiency binary all-polymer solar cells enabled by a novel polymer acceptor with an asymmetrical selenophene-fused backbone

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Science China Chemistry 2022年第2期65卷 309-317页

作者： Huiting fu Qunping Fan Wei Gao Jiyeon Oh yuxiang Li Francis Lin Feng Qi Changduk yang Tobin J.Marks Alex k.-y.Jen Department of Materials Science and Engineering City University of Hong KongKowloon 999077Hong KongChina Department of Chemistry City University of Hong KongKowloon 999077Hong KongChina Department of Energy Engineering School of Energy and Chemical EngineeringPerovtronics Research CenterLow Dimensional Carbon Materials CenterUlsan National Institute of Science and Technology(UNIST)50 UNIST-gilUlju-gunUlsan 44919Republic of Korea Department of Materials Science and Engineering University of WashingtonSeattleWashington 98195-2120USA Department of Chemistry and the Materials Research Center Northwestern UniversityEvanstonIL60208USA Institute for Advanced Studies City University of Hong KongKowloon 999077Hong KongChina

Despite the significant progress made recently in all-polymer solar cells(all-PSCs),it is still quite challenging to achieve high open-circuit voltage(V_(oc))and short-circuit current density(J_(sc))simultaneously in order to further improve their *** recent strategy of using selenophene to replace thiophene on the y6 based polymer acceptors has resulted in significantly improved J_(sc)s of the resulting ***,such modifications have also depressed V_(oc),which compromises the overall performance of the ***,we present the design and synthesis of a novel polymer acceptor,PyT-1S1Se,created by inserting an asymmetrical selenophene-fused framework to precisely manipulate optical absorption and electronic *** with the selenium-free analog,PyT-2S,and symmetrical selenium-fused analog,PyT-2Se,the PyT-1S1Se derived all-PSCs not only deliver optimized J_(sc)(24.1 mA cm^(−2))and V_(oc)(0.926 V)metrics,but also exhibit a relatively low energy loss of 0.502 ***,these devices obtain a record-high power conversion efficiency(PCE)of 16.3%in binary *** work demonstrates an effective molecular design strategy for balancing the trade-off between V_(oc) and J_(sc) to achieve highefficiency all-PSCs.

关键词： all-polymer solar cells polymer acceptors asymmetrical selenophene-fused backbone power conversion efficiencies stability

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An AlGaN/GaN HEMT with a reduced surface electric field and an improved breakdown voltage

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Chinese Physics B 2012年第8期21卷 360-364页

作者：谢刚 Edward Xu Niloufar Hashemi 张波 Fred y.fu Wai Tung Ng The Edward S.Rogers Sr.Electrical and Computer Engineering Department University of Toronto State key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Crosslight Software Inc.Burnaby BCCanada

A reduced surface electric field in an AlGaN/GaN high electron mobility transistor （HEMT） is investigated by employing a localized Mg-doped layer under the two-dimensional electron gas （2-DEG） channel as an electric field shaping layer. The electric field strength around the gate edge is effectively relieved and the surface electric field is distributed evenly as compared with those of HEMTs with conventional source-connected field plate and double field plate structures with the same device physical dimensions. Compared with the HEMTs with conventional sourceconnected field plates and double field plates, the HEMT with a Mg-doped layer also shows that the breakdown location shifts from the surface of the gate edge to the bulk Mg-doped layer edge. By optimizing both the length of Mg-doped layer, Lm, and the doping concentration, a 5.5 times and 3 times the reduction in the peak electric field near the drain side gate edge is observed as compared with those of the HEMTs with source-connected field plate structure and double field plate structure, respectively. In a device with VGS = -5 V, Lm 1.5 m, a peak Mg doping concentration of 8×10^17 cm-3 and a drift region length of 10 m, the breakdown voltage is observed to increase from 560 V in a conventional device without field plate structure to over 900 V without any area overhead penalty.

关键词： AlGaN/GaN HEMT reduced surface electric field Mg-doped layer breakdown voltage

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Optimal operation of water distribution networks under local pipe failures

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Journal of Central South University of Technology 2007年第3期14卷 436-441页

作者：田一梅 G.y.fu 迟海燕刘烨 School of Environmental Science and Engineering Tianjin University Department of Civil Engineering Faculty of Applied Science University of British Columbia Vancouver BC V6T 1Z4 Canada

The optimal operation of water distribution networks under local pipe failures, such as water main breaks, was proposed. Based on a hydraulic analysis and a simulation of water distribution networks, a macroscopic model for a network under a local pipe failure was established by the statistical regression. After the operation objectives under a local pipe failure were determined, the optimal operation model was developed and solved by the genetic algorithm. The program was developed and examined by a city distribution network. The optimal operation alternative shows that the electricity cost is saved approximately 11%, the income of the water corporation is increased approximately 5%, and the pressure in the water distribution network is distributed evenly to ensure the network safe operation. Therefore, the proposed method for optimal operation under local pipe failure is feasible and cost-effective.

关键词： water distribution network local pipe failure macroscopic model optimal operation

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Colletotrichum species associated with cultivated citrus in China

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fungal Diversity 2013年第4期61卷 61-74页

作者： F.Huang G.Q.Chen X.Hou y.S.fu L.Cai k.D.Hyde H.y.Li Institute of Biotechnology Zhejiang UniversityHangzhou 310058China State key Laboratory of Mycology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China Institute of Excellence in fungal Research Mae Fah Luang UniversityChiang Rai 57100Thailand

There have been considerable advances in the understanding of species concepts in the genus *** has lead to the need to carry out fresh surveys of Colletotrichum species associated with important *** species are associated with Citrus plants as saprobes,important pre-harvest and post-harvest pathogens,as well as *** this study,a total of 312 Colletotrichum strains were isolated from leaves,shoots and fruits of cultivated Citrus and Fortunella species with or without disease symptoms across the main citrus production areas in *** morphology of all strains were studied and multilocus(ACT,TUB2,CAL,GAPDH,GS,ITS)phylogeny *** were from four important species complexes of Colletotrichum,namely *** species complex,*** species complex,*** species complex and a final group including ***,which was rare on Citrus *** species belonging to the *** species complex comprised *** porioides and ***,the *** complex comprised *** and a new species *** and the *** complex included a new species,*** ability of strains to cause anthracnose on citrus fruits was tested by inoculation and strains of Colletotrichum gloeosporioides,*** and *** were pathogenic.

关键词： Citrus industry Citrus diseases Anthracnose Colletotrichum gloeosporioides Colletotrichum acutatum Colletotrichum boninense Morphology Phylogenetic analysis

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MODIFICATION OF ABSORPTION SPECTRUM OF GaAs/AlGaAs QUANTUM WELL INFRARED PHOTODETECTOR By POSTGROWTH ADJUSTMENT

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红外与毫米波学报 2006年第1期25卷 1-5页

作者： y fu yANG Chang-Li Theoretical Chemistry Department of Biotechnology Royal Institute of Technology AlbaNova S-106 91 Stockholm Sweden East China Normal University North Zhongshen Rd. 3663 200062 Shanghai China

Quantum well intermixing techniques modify the geometric shape of quantum wells to allow postgrowth *** tuning effect on the optical response property of a GaAs/AlGaAs quantum well infrared photodetector(QWIP) induced by the interdifussion of Al atoms was studied *** assuming an improvement of the heterointerface quality and an enhanced Al interdiffusion caused by postgrowth intermixings,the photoluminescence spectrum shows a blue-shifted,narrower and enhanced photoluminescence *** infrared optical absorption spectrum also shows the expected redshift of the response ***,the variation in the absorption peak intensity depends on the boundary conditions of the photo generated *** high-quality QWIP samples,the mean free path of photocarriers is long so that the photocarriers are largely coherent when they transport across quantum *** this case,the enhanced Al interdiffusion can significantly degrade the infrared absorption property of the *** effects are therefore needed to maintain and/or improve the optical properties of the QWIP device during postgrowth treatments.

关键词：吸收光谱量子阱红外光电探测器修正

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Dynamic analysis of geared transmission system for wind turbines with mixed aleatory and epistemic uncertainties

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Applied Mathematics and Mechanics(English Edition) 2022年第2期43卷 275-294页

作者： Chao fu kuan LU y.D.XU yongfeng yANG F.S.GU yushu CHEN Institute of Vibration Engineering Northwestern Polytechnical UniversityXi’an710072China Centre for Efficiency and Performance Engineering University of HuddersfieldHuddersfieldHD13DHU.K Dynamics Group Imperial College LondonLondonSW72AZU.K School of Astronautics Harbin Institute of TechnologyHarbin150001China

This paper deals with the co-existence of mixed aleatory and epistemic uncertainties in a wind turbine geared system for more reliable and robust vibration *** this end,the regression-based polynomial chaos expansion(PCE)is used to track aleatory uncertainties,and the polynomial surrogate approach(PSA)is developed to treat the epistemic *** non-intrusive dual-layer framework shares the same collocation pool,which is extracted from the Legendre ***,the regression technique has been implemented in both layers to enhance calculation *** validation is carried out to show the effectiveness of the proposed *** vibration behaviors of the geared transmission system are observed,and the mechanism behind is discussed in *** findings of this paper will contribute to the insightful understanding of such wind turbine geared systems under hybrid uncertainties and are beneficial for the condition monitoring.

关键词： geared system wind turbine hybrid uncertainty dynamic response efficient framework

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