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WALL EFFECTS ON FLOWS PAST TWO TANDEM CYLINDERS OF DIFFERENT DIAMETERS

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Journal of Hydrodynamics 2012年第1期24卷 1-10页

作者： jiang Ren-jie LIN Jian-zhong State Key Laboratory of Fluid Power Transmission and Control Zhejiang UniversityHangzhou 310027China China Jiliang University Hangzhou 310018China

Flows past two tandem cylinders of different diameters placed centrally in a channel with fixed centre-to-centre spacing 6D and diameter ratio are simulated based on the Lattice Boltzmann Method（LBM）.In all the simulations,the diameter of the smaller cylinder is chosen as the characteristic *** Reynolds number based on the average inflow velocity is 20-120 and studies are over the range of blockage ratio *** both Small-Big Arrangement（SBA）and Big-Small Arrangement（BSA）,the effects of the channel width and Reynolds number on the flow structures and force coefficients are *** show that the flows in BSA are more regular than those in SBA for the same flow *** BSA with and,the force coefficients all fluctuate with constant amplitudes and a coupled frequency,the coupled frequency becomes small as the blockage ratio decreases and by an exact test we give out the relation of the blockage ratio and Strouhal *** the blockage ratio decreases to 2,there exist pitchfork bifurcations in both SBA and BSA,and results show that the critical Reynolds numbers of pitchfork bifurcations for SBA and BSA are both between 60 and *** SBA with,the flow structure has a static asymmetric *** is found that the channel width has also an effect on the critical spacing where the flow changes from single body mode into co-shedding *** an accurate survey on flows past two cylinders with equal diameters placed inside a channel with the width,the relation between channel width and the critical spacing is given and results show that the critical spacing increases as the channel width increases.

关键词： two tandem cylinders different diameters blockage ratio critical spacing Lattice Boltzmann Method(LBM)

Co/CoO heterojunction rich in oxygen vacancies introduced by O_(2) plasma embedded in mesoporous walls of carbon nanoboxes covered with carbon nanotubes for rechargeable zinc-air battery

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Carbon Energy 2024年第7期6卷 14-25页

作者： Leijun Ye Weiheng Chen Zhong-jie jiang Zhongqing jiang Key Laboratory of Optical Field Manipulation of Zhejiang Province Department of PhysicsZhejiang Sci-Tech UniversityHangzhouChina Department of Mechanical Engineering Ningbo University of TechnologyNingboChina Guangzhou Key Laboratory for Surface Chemistry of Energy Materials Guangdong Engineering and Technology Research Center for Surface Chemistry of Energy MaterialsCollege of Environment and EnergySouth China University of TechnologyGuangzhouChina

Herein,Co/CoO heterojunction nanoparticles(NPs)rich in oxygen vacancies embedded in mesoporous walls of nitrogen-doped hollow carbon nanoboxes coupled with nitrogen-doped carbon nanotubes(P-Co/CoOV@NHCNB@NCNT)are well designed through zeolite-imidazole framework(ZIF-67)carbonization,chemical vapor deposition,and O_(2) plasma *** a result,the threedimensional NHCNBs coupled with NCNTs and unique heterojunction with rich oxygen vacancies reduce the charge transport resistance and accelerate the catalytic reaction rate of the P-Co/CoOV@NHCNB@NCNT,and they display exceedingly good electrocatalytic performance for oxygen reduction reaction(ORR,halfwave potential[EORR,1/2=0.855 V *** hydrogen electrode])and oxygen evolution reaction(OER,overpotential(η_(OER,10)=377mV@10mA cm^(−2)),which exceeds that of the commercial Pt/C+RuO_(2) and most of the formerly reported ***,both the aqueous and flexible foldable all-solid-state rechargeable zinc-air batteries(ZABs)assembled with the P-Co/CoOV@NHCNB@NCNT catalyst reveal a large maximum power density and outstanding long-term cycling ***-principles density functional theory calculations show that the formation of heterojunctions and oxygen vacancies enhances conductivity,reduces reaction energy barriers,and accelerates reaction kinetics *** work opens up a new avenue for the facile construction of highly active,structurally stable,and cost-effective bifunctional catalysts for ZABs.

关键词： heterojunction oxygen evolution/reduction reaction oxygen vacancies rechargeable zinc–air battery three‐dimensional nitrogen‐doped hollow carbon nanoboxes

SIMULATION STUDY OF CO-ASSEMBLY OF ABC TRIBLOCK COPOLYMER/NANOPARTICLE INTO MULTICOMPARTMENT HYBRIDS IN SELECTIVE SOLVENT

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Chinese Journal of Polymer Science 2013年第9期31卷 1225-1232页

作者： jie Cui Wei Li Wei jiang State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences

Co-assembly of ABC linear triblock copolymer/nanoparticle into bump-surface multicompartment hybrids in selective solvent was studied through self-consistent field theory （SCFT） simulation. Results from three-dimensional SCFT simulation showed that the hybrid morphology depended on the length and number of grafted chains, whereas the number and shape of bumps relied on nanoparticle size. Moreover, the simulation results showed that the length and number of grafted chains had equivalent effect on hybrid morphology. Calculated results indicated that entropy was a more important factor than enthalpy in the co-assembly.

关键词： Co-assembly Triblock copolymer Nanoparticle Multicompartment hybrid Self-consistent field theory.

Passive inter-modulation scattering analysis of reflector considering contact nonlinearity

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Chinese Journal of Aeronautics 2013年第2期26卷 463-469页

作者： jiang jie Li Tuanjie Liu Yicai School of Electromechanical Engineering Xidian University

Passive inter-modulation （PIM） is a form of nonlinear distortion caused by the inherent nonlinearities of the passive devices and components in RF/microwave system. It will degenerate the performance of communication system with broad-band channel and high-sensitivity receiver. Therefore, it is necessary to construct a model to simulate this process in order to predict the level of PIM. This paper is aimed at constructing some plate models with one-dimensional and two-dimensional contact nonlinearity sections illuminated by two-tone waves, and calculating the scattered field at a fixed-point in space using time-domain physical optics method. By taking fast Fourier transform （FFT）, we get the spectrum of the scattered field and then analyze the generated PIM products. At the end of this paper, some numerical examples are presented to show the influence rules of the relative factors on PIM. The results indicate the variation of the level of PIM with the number of the nonlinear regions, the nonlinear spacing, and the incident power levels.

关键词： Contact nonlinearity Nonlinear distortion Passive inter-modulation Reflector antennas Scattered field Time-domain physical optics

Direct calculation of voidage in the fine-grid CFD-DEM simulation of fluidized beds with large particles

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Particuology 2018年第5期16卷 23-33页

作者： Lihua Wang jie Ouyang Chuntao jiang Department of Applied Mathematics Northwestern Polytechnical UniversityXi'an 710129China

Voidage is important in determining the hydrodynamic behavior of a fluidized bed and estimating the drag force,Exact calculation methods are limited,especially in terms of determining the intersection bf a particle and cell,This paper presents a method of directly calculating ***,a judgment criterion of particle-cell overlap,which relies on the relationship of the distance from the particle to a cell face,edge,or vertex,is *** cases of the overlap volume of a particle and cell are then ascribed to a unified formula in the framework of the cuboid cell,This formula relies on the volume of two kinds of segments named the hemispherical segment and quarter-spherical *** presented method is validated by calculating the voidage of simple cubic ***,a three-dimensional fluidized bed with large particles is simulated and the results of numerical simulation are compared against experimental and simulation results reported in the *** numerical results are in good agreement with corresponding experimental data,and demonstrate the accuracy and reliability of the presented method in the three-dimensional simulation of fluidized beds.

关键词： Voidage Direct calculation Computational fluid dynamics-discrete element method Fluidized beds

Recent advances in geosynthetic-reinforced retaining Nails for highway applications

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Frontiers of Structural and Civil Engineering 2018年第2期12卷 239-247页

作者： jie HAN Yan jiang Chao XU Department of Civil Environmental and Architectural Engineering University of Kansas Lawrence KS 66044 USA Terracon Consultants Inc. 2201 Rowland Ave Savannah Georgia 31404 USA Department of Geotechnical Engineering College of Civil Engineering Tongji University Shanghai 200092 China

Geosynthetic-reinforced retaining （GRR） walls have been increasingly used to support roadways and bridge abutments in highway projects. In recent years, advances have been made in construction and design of GRR walls for highway applications. For example, piles have been installed inside GRR walls to support bridge abutments and sound barrier walls. Geosynthetic layers at closer spacing are used in GRR walls to form a composite mass to support an integrated bridge system. This system is referred to as a geosynthetic-reinforced soil （GRS）-integrated bridge systems （IBS） or GRS-IBS. In addition, short geosynthetic layers have been used as secondary reinforcement in a GRR wall to form a hybrid GRR wall （HGRR wall） and reduce tension in primary reinforcement and facing deflections. These new technologies have improved performance of GRR walls and created more economic solutions; however, they have also created more complicated problems for analysis and design. This paper reviews recent studies on these new GRR wall systems, summarizes key results and findings including but not limited to vertical and lateral earth pressures, wall facing deflections, and strains in geosynthetic layers, discusses design aspects, and presents field applications for these new GRR wall systems.

关键词： bridge geosynthetic highway reinforced wall

Longitudinal parameter identification of a small unmanned aerial vehicle based on modified particle swarm optimization

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Chinese Journal of Aeronautics 2015年第3期28卷 865-873页

作者： jiang Tieying Li jie Huang Kewei College of Mechanical and Electrical Engineering Beijing Institute of Technology

Abstract This paper describes a longitudinal parameter identification procedure for a small unmanned aerial vehicle （UAV） through modified particle swam optimization （PSO）. The proce- dure is demonstrated using a small UAV equipped with only an micro-electro-mechanical systems （MEMS） inertial mea,mring element and a global positioning system （GPS） receiver to provide test information. A small UAV longitudinal parameter mathematical model is derived and the modified method is proposed based on PSO with selective particle regeneration （SRPSO）. Once modified PSO is applied to the mathematical model, the simulation results show that the mathematical model is correct, and aerodynamic parameters and coefficients of the propeller can be identified accurately. Results are compared with those of PSO and SRPSO and the comparison shows that the proposed method is more robust and faster than the other methods for the longitudinal parameter identification of the small UAV. Some parameter identification results are affected slightly by noise, but the identification results are very good overall. Eventually, experimental validation is employed to test the proposed method, which demonstrates the usefulness of this method.

关键词： Aerodynamic parameters Local optimization Parameter identification Particle swarm optimization(PSO) Small unmanned aerialvehicle

Fabrication of Two-dimensional Monolayer and One-dimensional Wire of Zn-tetra-[3,5-di-t-butylphenyl]-porphyrin on Cu(100) Surface

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Chinese Journal of Structural Chemistry 2006年第8期25卷 992-996页

作者： QIAN Li-Ping WANG Xian XU Di WANG Zhou-Feng jiang Zhong-jie DENG wen-Li College of Materials Science and Engineering South China University of Technology Guangzhou 510640 China

We describe in this paper the fabrication of two- and one-dimensional nanostructures with organic molecular beam epitaxy （OMBE） principle based on controlled selfassembly by using adsorbate-substrate and intennolecular interactions that are important in molecular fabrication. Cu（100） single crystal was used as substrate in fabricating molecular nanostructures. Scanning tunneling microscopy （STM） experiments confirmed that Zn-tetra- [3,5-di-t-butylphenyl]porphyrin-molecules can be used to fabricate both monolayer and molecular wire on Cu（100） surface simultaneously, and the latter is arranged on the terrace edges. We herein briefly discuss the selectivity in terms of a mechanism in which the highest occupied and lowest unoccupied molecular orbitals （HOMO and LUMO） of the molecules interact with the surface.

关键词： fabrication two-dimensional monolayer one-dimensional molecular wire Zn-tetra-[3,5-di-t-butylphenyl]porphyrin

Effect of Heat Treatment on Microstructure and Property of Cr13 Super Martensitic Stainless Steel

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Journal of Iron and Steel Research International 2011年第11期18卷 60-66页

作者： LIU Yu-rong YE Dong YONG Qi-long SU jie ZHAO Kun-yu jiang wen College of Materials Science and Engineering Kunming University of Science and Technology Kunming 650093 Yunnan China Institute of Structural Materials Central Iron and Steel Research Institute Beijing 100081 China

The microstructures and mechanical properties of Cr13 super martensitic stainless steel after different heat treatments were studied. The results show that the structures of the steel after quenching are of lath martensite mixed with a small amount of retained austenite. With the raising quenching temperature, the original austenite grain size increases and the lath martensite gradually becomes thicker. The structures of the tempered steel are mixtures of tempered martensite and reversed austenite dispersed in the martensite matrix. The amount of reversed austenite is from 7.54% to 22. 49%. After different heat treatments, the tensile strength, the elongation and the HRC hardness of the steel are in the range of 813 1 070 MPa, 10.1%--21.2% and 21.33--32.37, respectively. The steel displays the best comprehensive mechanical properties after the sample is quenched at 1 050 ℃ followed by tempering at 650 ℃.

关键词： super martensitic stainless steel quenching tempering structure property reversed austenite