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Microstructure evolution of single crystal copper wires in cold drawing

science China(Technological sciences) 2007年第6期50卷 736-748页

作者： CHEN Jian1,2. YAN Wen1,2. WANG XueYan2.& FAN XinHui2.1 department of Applied Physics, Northwestern Polytechnical university, Xi’an 710072. China {2.chool of Material science and Chemical engineering, Xi’an Technological university, Xi’an 710032. China 1. department of Applied Physics Northwestern Polytechnical University Xi’an 710072 China 2. school of Material science and Chemical engineering Xi’an Technological University Xi’an 710032 China

The deformation microstructure evolution of single crystal copper wires produced by OCC method has been studied with the help of TEM, EBsD; OM. The results show that there are a small number of dendrites; twins in the undeformed single crystal copper wires. However, it is difficult to observe these dendrites in deformed single crystal copper wires. The structure evolution of deformed single crystal copper wires during drawing process can be divided into three stages. When the true strain is lower than 0.94, macroscopic subdivision of grains is not evident,; the microscopic evolution of deformed structure is that the cells are formed; elongated in drawn direction. When the true strain is between 0.94; 1.96, macroscopic subdivision of grains takes place,; the number of microbands located on {111}; cell blocks is much more than that with the true strain lower than 0.94. When the true strain is larger than 1.96, the macroscopic subdivision of grains becomes more evident than that with the true strain between 0.94; 1.96,; s-bands structure; lamellar boundaries will be formed. From EBsD analysis, it is found that part of 100 texture resulting from solidifying is transformed into 111; 112.due to shear deformation, but 100 texture component is still kept in majority. When the true strain is 0.94, the misorientation angle of dislocation boundaries resulting from deformation is lower than 14°. However, when the true strain arrives at 1.96, the misorientation angle of some boundaries will be greater than 50°,; the peak of misorientation angle distribution produced by texture evolution is located in the range between 2.°; 30°.

关键词： single crystal copper wires, deformation structure, electron backscattering diffraction, transmission electron microscopy

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Diversity of Pareto front: A multiobjective genetic algorithm based on dominating information

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控制理论与应用（英文版） 2010年第2期8卷 222-228页

作者： Wei CHEN 1 , Jingyu YAN 2., Mei CHEN 1 , Xin LI 1 (1.department of Automation, Hefei university of Technology, Hefei Anhui 2.0009, China {2. of mechanical and Automation engineering, the Chinese university of Hong Kong, Hong Kong, China) department of Automation Hefei University of Technology Hefei Anhui China department of mechanical and Automation {2. the Chinese University of Hong Kong Hong Kong China

In this paper, the diversity information included by dominating number is analyzed, and the probabilistic relationship between dominating number and diversity in the space of objective function is proved. A ranking method based on dominating number is proposed to build the Pareto front. Without increasing basic Pareto method’s computation complexity and introducing new parameters, a new multiobjective genetic algorithm based on proposed ranking method (MOGA-DN) is presented. simulation results on function optimization and parameters optimization of control system verify the efficiency of MOGA-DN.

关键词： Dominating number Ranking method Multiobjective Genetic algorithm

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Experimental study on the effect of gaseous and particulate emission from an ethanol fumigated diesel engine

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science China(Technological sciences) 2010年第12期53卷 3294-3301页

作者： YAO ChunDe1, ZHANG ZhiHui1,2. CHEUNG Chenshun2.& XU GuangLan1 1 state Key Laboratory of Engines, Tianjin university, Tianjin 300072. China 2.department of mechanical engineering, The Hong Kong Polytechnic university, Hong Kong, China 1. state Key Laboratory of Engines Tianjin University Tianjin 300072 China2. Department of Mechanical Engineering The Hong Kong Polytechnic University Hong Kong China

Experiments were conducted on a four-cylinder direct-injection diesel engine with 10% and 2.% of the engine load taken up by fumigation ethanol injected into the air intake of each cylinder, to investigate the gaseous, particulate mass (PM) emissions, and number concentration and size distribution of the engine under five engine loads at the maximum torque engine speed of 1800 r/min. The experimental results show that at low engine loads, the brake thermal efficiency (BTE) decreases with increase in fumigation ethanol; but at high engine loads, the BTE is not significantly changed by fumigation ethanol. Fumigation ethanol can effectively decrease in brake specific nitrogen oxides (BsNOx), particulate mass and number emissions but significantly increase in brake specific hydrocarbon (BsHC), brake specific carbon monoxide (BsCO) and proportion of BsNO/BsNO2. Also, the geometrical mean diameter of the particles (GMD) increases with increase in engine load but the diameter is not changed by fumigation ethanol in all cases.

关键词： diesel engine ethanol particulate number emissions

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A study of mechanical behavior of rock-fill materials with reference to particle crushing

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science China(Technological sciences) 2007年第z1期50卷 125-135页

作者： HUANG WenXiong1?, REN QingWen1 & sUN DeAn2.1 department of engineering Mechanics, Hohai {2., Nanjing 2.0098, China 2.department of Civil engineering, shanghai {2., shanghai 2.0072. China department of engineering Mechanics Hohai University Nanjing 210098 China department of Civil engineering Shanghai University Shanghai 200072 China

In rock-fill dams of 2.0 to 300 m high, maximum compressive stress can exceed 6 MPa. At such a high stress level, rock-fill materials may experience particle crushing during shear. The material behavior is highly sophisticated exhibiting pressure and density dependency as well as particle crushing effects. Through scrutinizing the relevant experimental data on rock-fill materials and sands published in the literatures, this paper is focused on understanding basic mechanical characteristics of this sort of materials in the light of constitutive modelling.

关键词： rock-fill materials granular materials compressibility shear dilatancy particle crushing

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Theoretical calculation of the finishing rolling impact work in non-quenched and tempered si-Mn steel

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science China(Technological sciences) 2006年第2期49卷 137-146页

作者： LIU Zhilin1, LIN Cheng1 & WANG Ping2.1. department of Materials and Chemical engineering, Liaoning Institute of Technology, Jinzhou 12.001, China 2. {2. department, Armor technique Institute of PLA, Changchun 130117, China department of Materials Chemical engineering Liaoning Institute of Technology Jinzhou 121001 China mechanical department Armor technique Institute of PLA Changchun 130117 China

Based on the hot-continuous rolling technology, the finishing rolling impact work α k of the non-quenched and tempered si-Mn steel is theoretically calculated with the covalent electron number nA of the strongest bond in alloying phases, and the smallest interface electron density difference Δρ of alloying phase interface and the number of atom states σ which keep the interface electron density continuous. Calculations show that the solution strengthening, the precipitation strengthening, and the interface strengthening will result in the decrease of the finishing rolling impact work α k, and the effects of the number of atom states σ which keep the interface electron density continuous on the finishing rolling impact work α k are different. Taking the impact work and the number of atom states σ 0 keeping the electron density continuous of the phase interface α-Fe/α-Fe-C between α-Fe and α-Fe-C as reference values, the impact work of the interface will increase when σ of some interface is larger than σ 0; otherwise, the impact will decrease. Therefore, the finishing rolling impact work α k can be calculated with the impact value of the refined α-Fe matrix and the influence amounts caused by the solution strengthening, the precipitation strengthening, the interface strengthening, and the number of atom states σ which keep the interface electron density continuous. The calculated results agree well with the measured ones. In this paper, the effect of s on the impact work is also discussed.

关键词： electron structure parameters, non-quenched and tempered steel, impact work and calculation.

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Early Hydration of Composite Cement with Thermal Activated Coal Gangue

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Journal of Wuhan university of Technology(Materials science) 2010年第1期25卷 162-166页

作者：郭伟 department of Material engineering Yancheng Institute of Technology Institute of Material science and engineering Nanjing University of Technology

Composite cement samples were prepared by mixing clinker, gypsum with burnt coal gangues which was calcined at various temperatures. The mechanical strength and Ca（OH）2.content in the cement paste were tested, and the paste composition and microstructure were analyzed by thermogravimetry-differential thermal analysis （TG-DsC）, X-ray diffraction（XRD）, scanning electronic microscopy （sEM） and pore structure analysis. Results demonstrate that the thermal activated coal gangue could accelerate the early hydration of cement clinker obviously, which promotes the gangue hydration itself. The early hydrated products of the cement are C-s-H gel, Ca（OH）2.and AFt. The cement with 30% （in mass） the gangue exhibits higher mechanical strength, and among all the cement samples the one with the gangue burnt at 700 ℃ displays the highest hydration rate, mechanical strength, the most gel pores and the lowest total porosity.

关键词： blended cement hydration microstructure hydration product

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Disequilibria between ^(2.0)Po and ^(2.0)Pb in surface waters of the southern south China sea and their implications

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science China Earth sciences 2006年第1期49卷 103-112页

作者： YANG Weifeng, HUANG Yipu1,2. CHEN Min1,2. ZHANG Lei, LI Hongbin, LIU Guangshan1,2.& QIU Yusheng1,2.1. department of Oceanography, Xiamen university, Xiamen 361005, China 2. state Key Laboratory of Marine Environmental science, Xiamen university, Xiamen 361005, China 1. department of Oceanography Xiamen University Xiamen 361005 China 2. state Key Laboratory of Marine Environmental science Xiamen University Xiamen 361005 China

Activities of the naturally occurring radionuclides, ^(2.0)Pb and ^(2.0)Po,were measured in both dissolved ( 0.45 μm) phases from surfacewaters of the southern south China sea. The average activity of particulate ^(2.0)Pb, 0.2. Bq/m^3 (n= 2.), accounted for about 12. of the total ^(2.0)Pb, which corresponds with values of open *** ^(2.0)Po, with an average activity of 0.43 Bq/m^3, accounted for about 40% of the total^(2.0)Po, which was much higher than those of open and eutrophic oceans. The residence times oftotal ^(2.0)Po and ^(2.0)Pb in surface waters estimated from an irreversible steady-state model were0.82.a and 1.16 a, respectively. The consistently high fractionation factor calculated either byscavenging rate constants (5.42. or K_d values (6.69) suggested that a significant fractionationoccurred between ^(2.0)Po and ^(2.0)Pb during their removal from solution to particles and that thetwo radionuclides had different biogeochemical cycling pathways in the oligotrophic south China ***, our results indicated that there exist different fractionation mechanisms between^(2.0)Po and ^(2.0)Pb in different marine environments: in eutrophic ocean, plankton detritus andfecal pellets are the main carrier of ^(2.0)Po and ^(2.0)Pb, by which ^(2.0)Po and ^(2.0)Pb havebeen scavenged and removed; while in oligotrophic ocean, microbes could become the main carrier of^(2.0)Po and fractionate ^(2.0)Po and ^(2.0)Pb significantly as a result of scarce plankton detritusand fecal pellets. These results suggest the use of ^(2.0)Po to trace marine biogeochemicalprocesses relating to microbial activities and the cycling of sulfur group elements (s, se, Te andPo).

关键词： south China sea, 2.0Po, 2.0Pb, disequilibria, scavenging.

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Dynamic behavior of polymer surface and the time dependence of contact angle

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science China Chemistry 2005年第6期48卷 553-559页

作者： WANG Xinping1, CHEN Zhifang1 & sHEN Zhiquan2.1. Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, department of Applied Chemistry, Zhejiang Institute of science and Technology, Hangzhou 310033, China 2. department of Polymer science and {2., Zhejiang university, Hangzhou 31002., China 1. department of Applied Chemistry Zhejiang Institute of Science and Technology Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry 310033 Hangzhou China 2. department of Polymer science and engineering Zhejiang University 310027 Hangzhou China

Time-dependent contact angles were measured by depositing sessile drops of wa-ter on the polymer surfaces and monitoring the drop shape as a function of time. It was found that contact angles decreased sharply with contact time and the equilibrium contact angle was finally attained after a certain time. Values of starting (θ s) and equilibrium contact angles (θ e) obtained by the sessile drop method depend on polymer properties. The Wilhelmy plate technique was used to measure advancing and receding contact angles. The variations of starting (θ s) and equilibrium contact angles (θ e), advancing (θ a) and receding contact angles (θ r) have been studied on the oxidized surface of polymers containing polybutadiene block to explore the cause of time-dependence in contact angle measurement and the meaning of θ s and θ e. The results showed the linear relationships between starting (θ s) and advancing contact angles (θ a), the equilibrium (θ e) and receding contact angles (θ r). The similar relationship was also established between the contact angle hysteresis (θ a?θ r) and differences (θ s ?θ e) in starting contact angles and equilibrium contact angles. Therefore, time-dependence in contact angle measurement was mainly attributed to the surface reconstruction when water drops were deposited on polymer surfaces. The starting contact angle was contributed by the hydrophobic component on polymer surface and the equilibrium contact angle mainly by the hydrophilic component of polymer. These results not only demonstrated the interdependency between two contact angle measurements, the sessile drop method and the Wilhelmy plate technique, but also provided the experimental evidence to explain the cause of time-dependent contact angle. This may also provide a new method to study dynamic behavior of polymer surface.

关键词： contact angle, surface dynamic behavior, polymer surface, dynamic contact angle, time-dependence.

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Application of polynomial chaos on numerical simulation of stochastic cavity flow

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science China(Technological sciences) 2010年第10期53卷 2853-2861页

作者： WANG XiaoDong1,2.& KANG shun1 1 Key Laboratory of Condition Monitoring and Control for Power Plant Equipment, Ministry of Education, school of Energy Power and mechanical engineering, North China Electric Power {2., Beijing 102.06, China 2.department of mechanical engineering, Vrije Universiteit Brussel, Brussels 1050, Belgium 1. Key Laboratory of Condition Monitoring and Control for Power Plant Equipment Ministry of Education School of Energy Power and Mechanical Engineering North China Electric Power University Beijing 102206 China2. Department of Mechanical Engineering Vrije Universiteit Brussel Brussels 1050 Belgium

In present paper,the mathematic background of intrusive polynomial chaos (IPC) method and coupling process with one dimension Euler equation were introduced. The IPC method was implemented for the 2. compressible stochastic Navier-stokes equations to simulate the non-deterministic behavior of a lid driven cavity flow under the influence of uncertainties. The driven velocity and fluid viscosity were supposed respectively to be the uncertain variable which has Gaussian probability distribution. Based on the validation with benchmark results,discussions were mainly focused on the statistic properties of velocity distribution. The results indicated the effect of IPC method on the simulation of propagation of uncertainty in the flow field. For the simulated results of 2. cavity flow,influence of the driven velocity uncertainty is larger than that of viscosity.

关键词： non-deterministic polynomial chaos numerical simulation lid driven cavity flow

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Characteristic analysis for a polynomial-like iterative equation

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Chinese science Bulletin 1998年第3期43卷 192-196页

作者： Janusz Matkowski 1 and ZHANG Weinian 2.1. department of Mathematics, Technical university, 43_300 Bielsko_Biala, Poland 2. department of Mathematics, sichuan Union university, Chengdu 610064, China department of Mathematics Technical University Bielsko-Biala Poland department of Mathematics Sichuan Union University Chengdu China

In the light of Euler’s idea for differential equations,a polynomial_like n _order iterative equation is discussed through analyzing its characteristic polynomial. An unproved result is verified rigorously for the fi... 详细信息

关键词： iterative dynamics functional equation characteristic.

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