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Relations between thickness of UHMWPE’s wear debris and positive pressure of tribological system

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Chinese science Bulletin 2008年第9期53卷 1435-1443页

作者： LIU HongTao1,2,3 & GE ShiRong1,3 1 Institute of Tribology and Reliability engineering, china university of Mining & technology, Xuzhou 221116, china 2 College of mechanical and electrical engineering, china university of Mining & technology, Xuzhou 221116, china 3 Biotribology Center, State Key Laboratory of Tribology, Xuzhou 221116, china Institute of Tribology and Reliability engineering China University of Mining & Technology Xuzhou China College of mechanical and electrical engineering China University of Mining & Technology Xuzhou China Biotribology Center State Key Laboratory of Tribology Xuzhou China

MiaoXAM2.5X-50X Ultrahigh Precision Surface 3D Profiler is introduced to research the relations be- tween thickness of UHMWPE’s wear debris and positive pressure of tribological system. Research re- sults show that thickness of wear debris owns evident classification, and the first grade thickness math model and the second grade thickness math model are built. By the second grade thickness math model, the true force condition in the tribological system can be gotten, and the model can be used as a tool to modify simulating parameters of the tribological system, and it is an important inspecting method to the airtight system which cannot be examined in real time. The first grade thickness math model can describe the true working load and surface condition of work piece in the tribological sys- tem, and is an effective description method for the running condition of frictional pairs. The research results at different lubricating conditions testify the relations between thicknesses of wear debris and positive pressure of the tribological system. The fractal relation between maximal thickness of wear debris and positive pressure is discussed. The conceptions of the immutability principle and charac- teristic granularity of wear debris thickness are brought forward and discussed. In conclusion, as a stable tribological parameter owning mechanical theory basis, wear debris thickness will play an im- portant part in fault diagnosis, especially for the airtight system such as artificial joint.

关键词：摩擦学磨损面厚度分形数学模型

Effect of Preparation Methods on mechanical Properties of PVA/HA Composite Hydrogel

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Journal of Bionic engineering 2010年第3期7卷 235-243页

作者： Dekun Zhang~1, Junjie Duan~1, Dagang Wang~2, Shirong Ge~2 1. School of Materials science and engineering, china university of Mining and technology Xuzhou 221116, P. R. china 2. School of mechanical and electrical engineering, china university of Mining and technology, Xuzhou 221116, P. R. china School of Materials science and engineering China University of Mining and Technology Xuzhou P. R. China School of mechanical and electrical engineering China University of Mining and Technology Xuzhou P. R. China

Poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) composite hydrogel specimens were prepared with 15% PVA and 1%,2%, 3%, 4% and 5% HA by repeated freezing-thawing. The tests of static and dynamic mechanical properties were carried out todiscuss the influence of different contents of HA and freezing-thawing cycles on the mechanical properties of PVA/HA compositehydrogel. The results of static mechanical tests showed that the PVA/HA composite hydrogel with 3% HA and ninefreezing-thawing cycles had excellent stress relaxation properties, higher relaxation ratio, lower stress equilibrium value andpresented better properties of creep and recovery. The results of dynamic mechanical test showed that the PVA/HA compositehydrogel with nine freezing-thawing cycles had higher storage modulus and loss modulus, so was the PVA/HA compositehydrogel with 3% HA.

关键词： composite hydrogel HA contents freezing-thawing cycles static properties dynamic properties

THE RESEARCH OF MIXED PRODUCT LINES OF MATERIAL DELIVERING SYSTEM DRAWN BY ORDERS

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THE RESEARCH OF MIXED PRODUCT LINES OF MATERIAL DELIVERING S...

2005年中国机械工程学会年会

作者： HOU Kaihu, YU Kaichao, ZHANG Yu (Dep. of Industry and engineering, faculty of mechanical and electrical engineering, kunming university of science and technology, kunming, 650093, china)

＜正＞To deal with mode of production small lot size and more varieties, the system of mixed production lines of material delivering system drawn by order was discussed. Firstly, the model of mixed production lines of material delivering system drawn by orders was build. Secondly, the logic of processing of the model was studied. To realize delivering components to production line in JIT＆PDT, three disposing ways were presented. Thirdly, Disposing flow of this system models were analyzed. Finally, The physical structure and function of the system was put forward.

关键词： delivering material system mixed product lines information technology

Statistical Thermal Fatigue-creep Modelling of Stainless Steel Materials

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Statistical Thermal Fatigue-creep Modelling of Stainless Ste...

The 8th International Conference on Reliability,Maintainability and Safety(ICRMS 2009)

作者： He Xiao-cong Innovative Manufacturing Research Centre faculty of mechanical and electrical engineering kunming university of science and technology kunming 650093 P.R.china

＜正＞The aim of this study is to investigate the creep fatigue behavior of stainless steel *** the low cycle thermal fatigue life model,Manson’s Universal Slopes equation was used as an empirical correlation which relates fatigue endurance to tensile *** test data were used in conjunction with different modes to establish the relationship between temperature and other *** statistical creep models were created for stainless steel *** order to correlate the results of short-time elevated temperature tests with long-term service performance at more moderate temperatures, different creep prediction models,namely Basquin model and Shcrby-Dorn model,were *** between the different creep prediction models were carried out for a range of stresses and temperatures.A linear damage summation method was used to establish life prediction model of stainless steels materials under fatigue creep interaction.

关键词： stainless steel materials low cycle thermal fatigue statistical creep model life prediction

External synchronization of two dynamical systems with uncertain parameters

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science china(Technological sciences) 2010年第3期53卷 731-740页

作者： HAN QingKai 1,SUN XiaoYu 2,YANG XiaoGuang 3 &WEN BangChun 1 1 School of mechanical engineering&Automation,Northeastern university,Shenyang 110004,china 2 School of electrical engineering,Shenyang university of technology,Shenyang 110023,china 3School of mechanical engineering,The university of Birmingham,Birmingham,B15 2TT,UK School of mechanical engineering & Automation Northeastern University School of electrical engineering Shenyang University of Technology School of mechanical engineering The University of Birmingham

External synchronization is addressed as two or more dynamical systems with synchronous motions,which is also regarded as master-slave *** this paper,two dynamical systems,one employs a hysteretic term to model the friction phenomenon,the other involves a hardening stiffness component with the third order of displacement due to flexible deformation,are controlled to converge to the same *** control strategy is extended from feedback control for all parameters known to adaptive control for linear parameters unknown and all parameters *** slave system can keep synchronous motions with the movements of master via the designed control strategy even all the parameters are not *** stability of synchronization error,the transient process into synchronization and the effects of parameters on the designed controller using different control strategies are *** simulation results unfold the feasibility and effectiveness of this synchronization method.

关键词： controlled synchronization uncertain parameters hysteretic system Duffing system

Calculation and characteristics analysis of blade pitch loads for large scale wind turbines

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science china(Technological sciences) 2010年第5期53卷 1356-1363页

作者： DAI JuChuan1,2,HU YanPing1,LIU DeShun1,2 & LONG Xin3 1 School of Electromechanical engineering,Hunan university of science and technology,Xiangtan 411201,china 2 College of mechanical and electrical engineering,Central South university,Changsha 410083,china 3 Hara XEMC Windpower Co.,Ltd.,Xiangtan 411000,china School of Electromechanical engineering Hunan University of Science and Technology Xiangtan China College of mechanical and electrical engineering Central South University Changsha China Hara XEMC Windpower Co. Ltd. Xiangtan China

Based on the electric pitch system of large scale horizontal-axis wind turbines,the blade pitch loads coming mainly from centrifugal force,aerodynamic force and gravity are analyzed,and the calculation models for them are established in this *** illustration,a 1.2 MW wind turbine is introduced as a practical sample,and its blade pitch loads from centrifugal force,aerodynamic force and gravity are calculated and analyzed separately and *** research results showed that in the process of rotor rotating 360o,the fluctuation of blade pitch loads is similar to cosine curve when the rotor rotational speed,in-flow wind speed and pitch angle are ***,the amplitude of blade pitch load presents quite a difference at a different pitch *** ways of calculation for blade pitch loads are of the universality,and are helpful for further research of the individual pitch control system.

关键词： blade pitch loads wind turbine individual variable-pitch pitch axis

Research on Product Information Management System Facing Remanufacture engineering

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Research on Product Information Management System Facing Rem...

全国第十届企业信息化与工业工程学术年会

作者： JIA Jian-shi, YU Kai-chao, TANG Xiu-ying faculty of mechanical and electrical engineering, kunming university of science and technology, kunming, 650093 china

Remanufacture engineering is an important characteristic and development trend of manufacturing system in the 21st Century, the product information management is very important to Remanufacture Engine

关键词： Management system Product information Remanufacture engineering

Research on the Long Time Swelling Properties of Poly (vinyl alcohol)/Hydroxylapatite Composite Hydrogel

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Journal of Bionic engineering 2009年第1期6卷 22-28页

作者： De-kun Zhang~(1,3), Da-gang Wang~2, Jun-jie Duan~(1,3), Shi-rong Ge~(2,3)1. School of Materials science and engineering, china university of Mining and technology, Xuzhou 221116, P. R. china2. School of mechanical and electrical engineering, china university of Mining and technology, Xuzhou 221116, P. R. china3. Biotribology Center, National Key Laboratory of Tribology, Tsinghua university, Beijing 100083, P. R. china School of Materials science and engineering China University of Mining and Technology Xuzhou P. R. China Biotribology Center National Key Laboratory of Tribology Tsinghua University Beijing P. R. China School of mechanical and electrical engineering China University of Mining and Technology Xuzhou P. R. China

Poly(vinyl alcohol)/hydroxylapatite(PVA/HA)composite hydrogel was prepared by repeated freezing and *** water loss properties of the resultant hydrogel were investigated by using optical *** time immersion tests of PVA/HA composite hydrogel were carried out in the diluted calf serum solution to study the change laws of swelling properties with the freezing-thawing cycles and HA *** micro-morphologies of PVA/HA composite hydrogel after long time immersion were observed by means of the high-accuracy 3D *** results show that the swelling process of PVA/HA composite hydrogel is the converse process of its water *** time swelling ratio curves of PVA/HA composite hydrogel in the calf serum solution are manifested as four stages of quick increase,decrease,slow decrease and stable balance,and its equilibrium swelling ratio decreases with the increase of freezing-thawing cycles and HA *** is revealed that the network structure of the composite hydrogel immersed for a long period is significantly improved with the increase of HA content. Perfect network structures of PVA/HA composite hydrogel as well as full and equilibrium tissues after swelling equilibrium are obtained when the HA content is 3% and the number of freezing-thawing cycles is 7.

关键词： poly (vinyl alcohol) hydroxyapatite composite hydrogel swelling property morphology

Effects of silver powder particle size on the microstructure and properties of Ag-Yb_2O_3 electrical contact materials prepared by spark plasma sintering

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Rare Metals 2010年第4期29卷 366-370页

作者： CHEN Xiaohua,JIA Chengchang,and LIU Xiangbing School of Materials science and engineering,university of science and technology Beijing,Beijing 100083,china School of Materials science and engineering University of Science and Technology Beijing Beijing China

mg-Yb203 electrical contact materials were fabricated by spark plasma sintefing （SPS）. The effects of silver powder particle size on the microstructure and properties of the samples were investigated. The surface morphologies of the sintered samples were examined by optical microscope （OM）, and the fracture morphologies were observed by scanning electron microscopy （SEM）. The physical and mechanical properties such as density, electrical resistivity, microhardness, and tensile strength were also tested. The results show that the silver powder particle size has evident effects on the sintered materials. Comparing with coarse silver powder （5 ktm）, homogeneous and fme microstmcture was obtained by fine silver powder （_〈0.5-1am）. At the same time, the electrical conductivity, microhardness, and tensile strength of the sin- tered samples with fine silver powder were higher than those of the samples with coarse silver powder. However, silver powder particle size has little influence on the relative densities, which of all samples （both by free and coarse silver powders） is more than 95%. The fracture characteristics are ductile.

关键词： composites electrical contact materials spark plasma sintering particle size microstructure physical properties mechanical properties