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Semi-analytical and computational investigation of different dust loading structures affecting the performance of a fibrous air filter

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Particuology 2014年第2期12卷 60-65页

作者： bin Xu ya Wu Pengyi Cui Department of Environmental Engineering Tongji University State Key Laboratory of Pollution Control and Resource Reuse Tongji University

In this study, a semi-analytical model was developed to illustrate the relationship between filtration performance （filtration efficiency and pressure drop） and dust loading under two different particle deposit structures based on theoretical analysis and computational fluid dynamic （CFD） technology. Under the compact deposit structure, within the practical parameter ranges （fiber diameter, air velocity, dust loading mass）, a slight efficiency enhancement （∽10%） occurred at the most penetration particle size （MPPS） and pressure drop increased significantly （∽100%） in response to the solidity increase from 5% to 15%. However, under the dendritic particle deposit structure, both filtration efficiency （∽40%） and pressure drop （4600%） increased significantly with the same solidity increase due to the larger air velocity and swerve change between fibers.

关键词： Particle filtrationDeposition structureLiquid droplet filtrationFilter dust loading

Charged ultrafine particle filtration through vehicular cabin air filters

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Particuology 2016年第5期14卷 1-5页

作者： bin Xu Yu gong ya Wu Department of Environmental Engineering Tongji University 1239 Siping Road Shanghai 200092 China Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3) Shanghai 200433 China

Understanding the effectiveness of cabin air filters is important for assessing human exposure to ultra- fine particles （UFPs） of vehicular origin. The filtration efficiency of vehicular UFPs with electric charges was investigated for different electric charge characteristics （charge state, charge polarity）. The average filtration efficiency increased ~10% as the electric charge state on the particles changed in distribution from lightly charged to highly charged. The enhancement of filtration efficiency due to electric charge was different at various filter-face air velocities. As electric charges increased, the filtration efficiency increased 12% and 9% at low air velocity （0.1 m/s） and high air velocity （0.S m/s）, respectively. The filter fiber material poses somewhat effect on the filtration efficiency change due to the electric charge. The effects of filter usage and charge polarity on filtration efficiency due to the electric charge were negligi- ble. A coefficient was empirically derived and successfully accounts for the electric charge effect on UFP filtratinn efficiency.

关键词： Particle filtration Electric charge Filtration efficiency Vehicular particle

A finite element solution for frictional sliding contact between hyper-elastic and rigid bodies

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A finite element solution for frictional sliding contact bet...

Cloud point extraction coupled with HPLC-UV for the determination of phthalate esters in environmental water samples

第八届中国功能材料及其应用学术会议

作者： Chen ya-bin China University of Petroleum(East of China) college of pipelineand civil engineering

ISBN: (纸本)9783037859698

This paper is devoted to the analysis of frictional contact problems with largedeformations and displacements between hyper-elastic body and rigid *** material nonlinearity andcontact nonlinearity are separated and,the geometrically nonlinear behavior is described by the total Lagrange *** Coulomb friction law is employed to simulate the friction between rigid vessel and rubber by the use of augmented Lagrange approach with node-to-segment formulation.A formulation of finite element is taken in this paper to describe the frictional contact problem,which is solved by the Newton-Raphson iterative *** is shown that the augmented Lagrange technique significantly avoids locking and over-constraining and provides optimal convergence ***,the numerical results show that the accuracy and efficiency of augmented Lagrange approach in modeling large deformation frictional contact problem.

关键词： augmented Lagrange frictional contact Rubber Finite element

来源： cnki会议评论

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Journal of Environmental Sciences 2007年第7期19卷 874-878页

作者： WANg Ling JIANg gui-bin CAI ya-qi HE bin WANg ya-wei SHEN Da-zhong School of Chemistry and Chemical Engineering Shah Dong University Jinan 250100 China. State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Scienees Beijing 100085 China

A method based on cloud point extraction was developed to determine phthalate esters including di-ethyl-phthalate （DEP）, di- （2-ethylhexyl）-phthalate （DEHP） and di-cyclohexyl-phthalate （DCP） in environmental water samples using high-performance liquid chromatography separation and ultraviolet detection （HPLC-UV）. The non-ionic surfactant Triton X-114 was chosen as extraction solvent. The parameters affecting extraction efficiency, such as concentrations of Triton X-114 and Na2SO4, equilibration temperature, equilibration time and centrifugation time were evaluated and optimized. Under the optimum conditions, the method can achieve preconcentration factors of 35, 88, 111 and detection of limits of 2.0, 3.8, 1.0 ng/ml for DEP, DEHP and DCP in 10-ml water sample, respectively. The proposed method was successfully applied to the determination of trace amount of phathalate esters in effluent water of the wastewater treatment plant and the lixivium of plastic fragments.

关键词： phthalate esters cloud point extraction Triton X-114 non-ionic surfactant, HPLC-UV

Trusted gPSR protocol without reputation faking in VANET

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The Journal of China Universities of Posts and Telecommunications 2015年第5期22卷 22-31 55,55页

作者： Xiao ya Zheng Shihui Sun bin School of Computer Science Beijing University of Posts and Telecommunications

In vehicular ad hoc network(VANET), misbehaviors of internal nodes, such as discarding packets, may lead to a rapid decline in packet delivery ratio. To solve this problem, an improvement of greedy perimeter stateless routing(gPSR) protocol is presented. In the new protocol, trustworthiness is considered in the route selection process. The trustworthiness is measured by an objective trust model based on the subjective trust model Dy Trust. And the reputation value which reflects the trustworthiness of each node is calculated and broadcasted by the intersection nodes. Specially, besides resisting the packet-discarding behavior of selfish nodes, this protocol also includes a location detection process to resist the location-faking behavior of malicious nodes. As a result, the selfish nodes and the malicious nodes can be excluded from the network. In addition, compared with improved gPSR protocol, the presented one is able to resist one kind of reputation-faking attack and has better performance in simulation.

关键词： trusted routing protocol reputation model vehicula

Preparation and electrochemical properties of carbon-coated LiFePO_4 hollow nanofibers

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International Journal of Minerals,Metallurgy and Materials 2016年第4期23卷 474-480页

作者： bin-bin Wei yan-bo Wu Fang-yuan Yu ya-nan Zhou College of Environmental and Chemical Engineering Dalian Jiaotong University

Carbon-coated LiFePO_4 hollow nanofibers as cathode materials for Li-ion batteries were obtained by coaxial electrospinning. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller specific surface area analysis, galvanostatic charge–discharge, and electrochemical impedance spectroscopy（EIS） were employed to investigate the crystalline structure, morphology, and electrochemical performance of the as-prepared hollow nanofibers. The results indicate that the carbon-coated LiFePO_4 hollow nanofibers have good long-term cycling performance and good rate capability： at a current density of 0.2C（1.0C = 170 mA ·g^-1） in the voltage range of 2.5–4.2 V, the cathode materials achieve an initial discharge specific capacity of 153.16 mA h·g^-1 with a first charge–discharge coulombic efficiency of more than 97%, as well as a high capacity retention of 99% after 10 cycles; moreover, the materials can retain a specific capacity of 135.68 mA h·g^-1, even at 2C.

关键词： electrospinning lithium-ion batteries carbon coatings phosphates nanofibers electrochemical properties

Effect of mold electromagnetic stirring on solidification structure and solute segregation in continuous casting bloom

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Journal of Iron and Steel Research International 2022年第1期29卷 124-131页

作者： Dong-bin Jiang Li-feng Zhang ya-dong Wang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China State Key Lab of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004HebeiChina

The effect of mold electromagnetic stirring(M-EMS)on the solidification structure and solute segregation in the continuous casting bloom of U78CrV steel is *** solute distribution in the macroscale is analyzed using a carbon–sulfur analyzer and that in the microscale is measured with an electron probe *** Image-J software is applied to analyze the number density and area ratio of segregation *** results show that the segregation spots are mainly located in the columnar to equiaxed transition zone and the equiaxed zone,which are enriched with C,Cr,and Mn *** the M-EMS applied,the columnar grain inclines to the upstream *** the current intensity increases,the deflecting angle of columnar grain rises,especially with the current intensity larger than 300 ***,the center segregation shows a declining trend and the area fraction of the equiaxed zone rises ***,it is found that the area ratio and number density of segregation spots increase with the higher current intensity of M-EMS.

关键词： Solidification structure Macrosegregation Mesosegregation Segregation spot Mold electromagnetic stirring

Based on the Second Virial Coefficient(A2)to Study Effect of the Synergistic Action of Solvent and External Electric Field on the Solution Behavior and Film's Condensed State Structure

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Chinese Journal of Polymer Science 2022年第5期40卷 478-490页

作者： ya-Nan guo Hao Zhang bin Liu Dan Lu State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun 130012China

The solventnatures are crucial to deeply reveal solution behavior of macromolecular chains,physical essence of condensed state structures formation of the film as well as the photoelectronic devices *** on the second virial coefficient(A2),effect of the synergistic action of solvents and external electric field on both solution behavior and the film’s condensed state structure for the semi-rigid conjugated polymer,poly[2-methoxy-5-(2’-ethylhexoxy)-1,4-phenylvinylene](MEH-PPV)was investigated by dynamic/static light scattering,photoluminescence spectroscopy and transmission electron microscopy,*** was found that although the MEH-PPV solutions with different solvents(toluene,chlorobenzene,chloroform and tetrahydrofuran)all could generate a response to the external electric field,the degree of response varied significantly with the change of solvent ***,ordered degree of the film from the solutions was also obviously *** essential reason for this responsive difference was firstly revealed in the research,which actually depended on the degree of interaction between the solute and solvent,and this degree of interaction could be quantitatively described by the second virial coefficient(A2).The bigger the A2,the stronger the interaction between solvent and solute in the solution,and the stronger the response to the external electric ***,under the induction of external electric field,chains aggregations with different sizes were formed accompanied by large-scale chains ordered structure in the *** ordered structure not only can effectively transfer to film prepared by the precursor solution but also is beneficial to enhance the carrier mobility and device efficiency of the photoelectronic film.

关键词： Semi-rigid conjugated polymer External electric field Second virial coefficient Solution behavior Condensed state structure

In situ TiN-reinforced CoCr2FeNiTi(0.5) high-entropy alloy composite coating fabricated by laser cladding

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Rare Metals 2020年第10期39卷 1190-1195页

作者： ya-Xiong guo Qi-bin Liu Xiao-Juan Shang College of Materials and Metallurgy Guizhou UniversityGuiyang 550025China guizhou Province Key Laboratory of Materials Structure and Strength Guiyang 550025China

The fcc structural CoCr2 FeNiTi(0.5) high-entropy alloy(HEA) composite coating with TiN particles reinforced was acquired by laser cladding on the commercial904 L stainless *** results show that phase structure is mainly composed of fcc solid solution and TiN *** coating exhibits excellent structural stability below850℃.The microstructure consists of irregular dendrite and TiN *** electron microscopy(TEM) results reveal that the close-packed plane of fcc phase is(111) with interplanar spacing of ~ 0.208 *** interface between TiN and fcc matrix is *** the angle of boundary between dendrite and matrix is ~ 65°.The hardness and corrosion resistance of coating have much improvement compared with those of substrate.

关键词： TiN particle reinforced High-entropy alloy Semi-coherent interface Laser cladding