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Deposition behavior of multi-particle impact in cold spraying process

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International Journal of Minerals,Metallurgy and Materials 2010年第5期17卷 635-640页

作者： xiang-lin Zhou xiang-kun Wu Hui-hua Guo Jian-guo Wang Ji-shan Zhang State Key Laboratory for Advanced Metals and Materials University of Science mad Technology Beijing Beijing 100083 China

In the practical cold-spraying process, a number of particles impact onto a substrate and then form a coating. To study the deformation behavior and multi-particle interactions, single-particle, two-particle, and three-particle impacts were simulated using the ANSYS/LS-DYNA version 970. A copper coating was prepared and scanning electron microscopy （SEM） was employed to analyze the microstructures of the powders and the coating. Numerical results reveal that the critical deposition velocity is 600 m/s for a copper particle/copper substrate. The particles deform more fully due to multi-particle interactions, such as tamping, interlocking, and extrusion effects. The compression ratio increases from 40% to 70% as a result of the tamping effect. This is beneficial for achieving the cold-sprayed coating. The multi-particle morphology and compression ratio in the experiment are consistent with those of simulation results. Based on these results, the coating of high performance can be prepared through selecting appropriate parameters and suitable pre-treatment processes.

关键词： spraying deposition interfaces particle interactions bonding simulation

Computational Simulation and Electrochemically Deposited Molecularly Imprinted Polymer-coated Carbon Glass Electrode for Triclosan Detection

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Chinese Journal of Structural Chemistry 2020年第7期39卷 1252-1260页

作者： GAO Bo TANG shan-shan LIU jun-Bo JIN Rui-Fa College of Resources and Environment Jilin Agricultural UniversityChangchun 130118China College of Chemistry and Chemical Engineering Chifeng UniversityChifeng 024000China

Triclosan,a kind of multi-purpose biocide,was widely used household cleaning and personal care *** widespread use of triclosan has potential risk to the ecotype and human health due to its release into sediment,surface and ground water resources.A molecularly imprinted electrochemical sensor for triclosan detection in cosmetic emulsion was synthesized and *** order to determine the suitable monomer and evaluate the template-monomer geometry as well as the interaction energy in the template-monomer prepolymerization mixture,a computational study was *** found that the complex formed by hybrid monomers(triclosan(o-phenylenediamine-co-resorcinol))had more hydrogen bonds and larger binding energy than that by single kind of monomers(triclosan(o-phenylenediamine)2 and triclosan(resorcinol)2).Therefore,hybrid monomers were used to synthesize the imprinted electrochemical sensor,which exhibits a high sensitivity and selectivity for triclosan sensing with the detection range 0~15 ng·mL-1 and detection limit 0.41 ng·mL-1.

关键词： computational simulation electrochemical synthesis molecular imprinting triclosan hybrid monomers

Lattice Boltzmann Method for Diffusion-Reaction-Transport Processes in Heterogeneous Porous Media

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Chinese Physics Letters 2004年第7期21卷 1298-1301页

作者： XUYou-Sheng ZHONGYi-jun HUANGGuo-xiang DepartmentofPhysics ZhejiangNormalUniversityJinhua321004 DepartmentofChemistry ZhejiangNormalUniversityJinhua321004 DepartmentofPhysics EastChinaNormalUniversityShanghai200062

Based on the lattice Boltzmann method and general theory of fluids flowing in porous media, a numerical model is presented for the diffusion-reaction-transport (DRT) processes in porous media. As a test, we simulate a DRT process in a two-dimensional horizontal heterogeneous porous medium. The influence of gravitation in this case can be neglected, and the DRT process can be described by a strongly heterogeneous diagnostic test strip or a thin confined piece of soil with stochastically distributing property in horizontal directions. The results obtained for the relations between reduced fluid saturation S, concentration c1, and concentration c2 are shown by using the visualization computing technique. The computational efficiency and stability of the model are satisfactory.

关键词： Porous materials

Effects of Ce^(3+) doping on the structure and magnetic properties of Mn-Zn ferrite fibers

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Rare Metals 2009年第2期28卷 151-155页

作者： xiang, jun Shen, xiangqian Zhu, Yongwei School of Materials Science and Engineering Jiangsu University Zhenjiang 212013 China School of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

Ce3+-doped Mn-Zn ferrite fibers were successfully prepared by the organic gel-thermal decomposition method from metal salts and citric acid. The composition,structure,and magnetic properties of these ferrite fibers were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),and vibrating sample magnetometer (VSM). The results show that Mn0.2Zn0.8Fe2-xCexO4 (x = 0-0.04) fibers are featured with an average grain size of 11.6-12.7 nm,with diameters ranging between 1.0 to 3.5 μm and a high ...

关键词： ceramic fibers Mn-Zn ferrite thermal decomposition magnetic properties Ce3+-doped

A Novel Process for High-efficient Synthesis of One-dimensional Carbon Nanomaterials from Flames

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Journal of Materials Science & Technology 2008年第4期24卷 603-607页

作者： xiang QI jun ZHANG Chunxu PAN Department of Physics and Key Laboratory of Acoustic and Photonic Materials and Devices of Ministry of Education Wuhan University Wuhan 430072 China Center for Electron Microscopy Wuhan University Wuhan 430072 China

The substrate pre-treatment plays a key role in obtaining hollow-cored carbon nanotubes （CNTs） and solid-cored carbon nanofibers （CNFs） from flames. This paper introduces a simply and high-efficient process by coating a NiSO4 or FeSO4 layer on the substrate as catalyst precursors. Comparing with the regular pre-treatment methods, the present experiments showed that the coating pre-treatment provided the following advantages： 1） greatly shortening the synthesis time; 2） available variant substrates and carbon sources; 3） narrowing the diameters distribution. The sulfate is considered to be a crucial factor at the growth of CNTs and CNFs, because it increases the surface energy of catalyst particles and the surface specificity of sulfurs action in metallic grains. This novel process provides a possibility for high quality and mass production of CNTs and CNFs from flames.

关键词： Carbon nanotubes Carbon nanofibers Flames Sulfate

Continuous Orbit Equivalence of Semigroup Actions

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1581-1598页

作者： xiang Qi QIANG Cheng jun HOU School of Mathematical Science Yangzhou UniversityYangzhou 225002P.R.China

We introduce notions of continuous orbit equivalence and its one-sided version for countable left Ore semigroup actions on compact spaces by surjective local homeomorphisms,and characterize them in terms of the corresponding transformation groupoids and their operator *** particular,we show that two essentially free semigroup actions on totally disconnected compact spaces are continuously orbit equivalent if and only if there is a canonical abelian subalgebra preserving C^(∗)-isomorphism between the associated transformation groupoid C^(∗)-*** also give some examples of orbit equivalence,consider the special case of semigroup actions by homeomorphisms and relate continuous orbit equivalence of semigroup actions to that of the associated group actions.

关键词： Semigroup action continuous one-sided orbit equivalence continuous orbit equivalence groupoid C^(∗)-algebras

Older liver grafts from donation after circulatory death are associated with impaired survival and higher incidence of biliary non-anastomotic structure

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Hepatobiliary & Pancreatic Diseases International 2023年第6期22卷 577-583页

作者： Tian Shen shan-Hua Zheng jun Chen Zhi-Sheng Zhou Meng-Fan Yang xiang-Yan Liu jun-Li Chen Shu-Sen Zheng Xiao Xu Department of Hepatobiliary and Pancreatic Surgery Shulan(Hangzhou)HospitalHangzhou 310022China Division of Hepatobiliary Pancreatic Surgery The First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China Key Laboratory of Integrated Oncology and Intelligent Medicine of Zhejiang Province Department of Hepatobiliary and Pancreatic SurgeryAffiliated Hangzhou First People’s HospitalZhejiang University School of MedicineHangzhou 310006China China Liver Transplant Registry Hangzhou 310003China NHC Key Laboratory of Combined Multi-organ Transplantation Hangzhou 310003China Institute of Organ Transplantation Zhejiang UniversityHangzhou 310003China

Background:Grafts from older donors after circulatory death were associated with inferior outcome in liver transplants in the *** it has seemed to remain controversial in the last decade,as a result of modified clinical protocols,selected recipients,and advanced technology of organ perfusion and *** present study aimed to examine the impact of older donor age on complications and survival of liver transplant using grafts from donation after circulatory death(DCD).Methods:A total of 944 patients who received DCD liver transplantation from 2015 to 2020 were included and divided into two groups:using graft from older donor(aged≥65 years,n=87)and younger donor(age<65 years,n=857).Propensity score matching(PSM)was applied to eliminate selection ***:A progressively increased proportion of liver transplants with grafts from older donors was observed from 1.68%to 15.44%during the study *** well-balanced older donor(n=79)and younger donor(n=79)were 1:1 *** were significantly more episodes of biliary nonanastomotic stricture(NAS)in the older donor group than the younger donor group[15/79(19.0%)vs.6/79(7.6%);P=0.017].The difference did not reach statistical significance regarding early allograft dysfunction(EAD)and primary non-function(PNF).Older livers had a trend toward inferior 1-,2-,3-year graft and overall survival compared with younger livers,but these differences were not statistically significant(63.1%,57.6%,57.6%vs.76.9%,70.2%,67.7%,P=0.112;64.4%,58.6%,58.6%vs.76.9%,72.2%,72.2%,P=0.064).The only risk factor for poor survival was ABO incompatible transplant(P=0.008)in the older donor *** the subgroup of ABO incompatible cases,it demonstrated a significant difference in the rate of NAS between the older donor group and the younger donor group[6/8(75.0%)vs.3/14(21.4%);P=0.014].Conclusions:Transplants with grafts from older donors(aged≥65 years)after circulatory death are more frequently associated with inferior outcome com

关键词： Older donor Liver transplantation Survival Biliary stricture Donation after circulatory death

Wear-resistant coating spraying technique for wear-proofing cover of coke dry quenching furnace

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Journal of Iron and Steel Research International 2019年第2期26卷 123-129页

作者： Zhang-fu Yuan shan-shan Xie xiang-tao Yu Jian Liu Ping Du Zhi-hua Li Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China Jiangsu Shagang Iron and Steel Research Institute Co. Ltd.Suzhou 215625JiangsuChina

During the operation of a coke dry quenching system of coking plant, wear-proofing cover of the boiler was seriously eroded, and even the ceiling tube of the boiler was worn and torn. Thus, attentions were paid to the research, development and application of the wear-resistant coating spraying technique for wear-proofing cover of the coke dry quenching furnace. The Cr3C2–NiCr coatings for wear-proofing cover were fabricated via supersonic arc spraying process, and the residual coating of wear-proofing cover would be sampled for being analyzed after two years. The coating presents a dense microstructure with few pores and micro-cracks (the porosity is 4.65%). After thermal spraying of the wear-proofing cover, the hardness and the wear resistance of the surface are improved. The remaining coating is continuous and compact, with an average thickness of about 147μm. Transverse micro-cracks parallel to the spreading direction of the coating surface are displayed on different areas of the coating, which demonstrates its serious erosion wear effect. The main chemical component of white zone is Fe–18Cr–Ni. The Cr level of light gray phase is about 77.57 wt.% and the O level is 22.43 wt.%. And the main chemical components of dark gray phase are C, O, Al, Si and Ca. X-ray diffraction patterns were adopted to implement phase analysis on the surface of coating sample, which indicated that the coating was composed of a large amount of Cr3O2 and a small amount of metal Cr.

关键词： Coke dry quenching Wear-proofing cover Thermal spraying technique Coating property Cr3C2-NiCr coating

Amplitude Compensation for One-Way Wave Propagators in Inhomogeneous Media and its Application to Seismic Imaging

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Communications in Computational Physics 2008年第1期3卷 203-221页

作者： jun Cao Ru-shan Wu Department of Earth and Planetary Sciences University of CaliforniaSanta CruzCA 95064USA CSIDE Institute of Geophysics and Planetary PhysicsUniversity of CaliforniaSanta CruzCA 95064USA.

TheWKBJ solution for the one-waywave equations inmediawith smoothly varying velocity variation with depth,c(z),is reformulated from the principle of energy flux conservation for acoustic *** formulation is then extended to general heterogeneous media with local angle domain methods by introducing the concepts of Transparent Boundary Condition(TBC)and Transparent Propagator(TP).The influence of the WKBJ correction on image amplitudes in seismic imaging,such as depth migration in exploration seismology,is investigated in both smoothly varying c(z)and general heterogeneous *** also compare the effect of the propagator amplitude compensation with the effect of the acquisition aperture correction on the image *** results in a smoothly varying c(z)medium demonstrate that theWKBJ correction significantly improves the one-way wave propagator amplitudes,which,after compensation,agree very well with those from the full wave equation *** for a point scatterer in a smoothly varying c(z)medium show that the WKBJ correction has some improvement on the image amplitude,though it is not very *** results in a general heterogeneous medium(2D SEG/EAGE salt model)show similar *** the acquisition aperture correction is applied,the image improves significantly in both the smoothly varying c(z)medium and the 2D SEG/EAGE *** comparisons indicate that although theWKBJ compensation for propagator amplitude may be important for forward modeling(especially for wide-angle waves),its effect on the image amplitude in seismic imaging is much less noticeable compared with the acquisition aperture correction for migration with limited acquisition aperture in general heterogeneous media.

关键词： Propagator amplitude image amplitude WKBJ beamlet local angle domain seismic imaging