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Effects of MoS_2.on mechanical and tribological properties of NiCr-based alloys

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中国有色金属学会会刊：英文版 2000年第3期10卷 328-327,329-331页

作者： XIONG Dang sheng(熊党生) 1. PENG Chao qun(彭超群) 2. LIU Jin long(刘金龙) 1.1. college of {1. engineering, China university of mining and Technology, xuzhou 2.1.08, P.R.China 2. State Key Lab for Powder Metallurgy, Central South Unive China Univ Min & Technol Coll Mech Engn Xuzhou 221008 Peoples R China Cent S Univ Technol State Key Lab Powder Met Changsha 410083 Peoples R China

Ni Cr based alloys with a wide temperature range self lubrication were made by hot pressing the mixture powder of alloyed Ni Cr powder, elemental Mo, Al, Ti and B powders and MoS 2.powder. The mechanical and tribological properties of these alloys when rubbing with Al 2. 3 ceramics and W1.Cr4V high speed steel were measured in the temperature range of 2.～700 ℃, and the mechanisms of self lubrication and wear resistance were studied. The results showed that the alloy containing 1.% MoS 2.has the best combination of mechanical properties, antifriction and wear resistance. Over a wide temperature range from 2. ℃ to 700 ℃, when rubbing with Al 2. 3, its friction coefficient and wear rate are 0.1.～0.3 and (1.1.1.5)1. -1. m 3/(N·m), respectively; when rubbing with the high speed steel, those values are 0.1. ～ 0.2. and (0.6～3.2.×1. -1. m 3/(N·m), respectively.

关键词： Ni Cr based alloys molybdenum disulfide self lubrication tribological properties

Description to wear debris boundaries by radar graph fractal method

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Chinese Science Bulletin 2007年第16期52卷 2285-2290页

作者： LIU HongTao1.2.& GE ShiRong1.1.Institute of Tribology and Reliability engineering,China {1. of mining & Technology,xuzhou 2.1.08,China 2.college of mechanical and electrical engineering,China {1. of mining & Technology,xuzhou 2.1.1.,China Institute of Tribology and Reliability engineering China University of Mining and Technology Xuzhou 221008 China

In this paper,radar graph fractal method is introduced to describe wear debris boundaries. Research results show that it is a nice way to describe wear debris boundaries. Since the longest axis is selected as the first coordinate axis,its center point selected as the center point of the radar graph,and the co-ordinate value of wear debris boundary selected as the measure parameter,the limitations existing in Yard fractal measure method can be avoided. For any wear debris,its radar graph fractal dimension value is one and only,and as the wear debris shape changes from round to strip,the radar graph fractal dimension value also changes from low to high,showing strong uniqueness and independence. Due to the fact that the researched wear debris is gotten in different wear states,the results also prove that radar graph fractal dimension value is correlated with frictional pairs work condition and wear state. Radar graph fractal method is compared with Yard fractal measure methods,and results show that ra-dar graph fractal dimension values gotten from different wear debris have enough value grads to avoid effect of errors,and provide higher sensitivity for wear debris shape. This paper also discusses the influencing factors for radar graph fractal method. With the increase of the decomposing degree value,the radar graph fractal dimension tends to keep stable at one certain value,showing the typical characteristic of the fractal theory. All this proves that radar graph fractal method is an effective description method for wear debris boundaries.

关键词：磨粒边界雷达图表分形法

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 {1. of mining & Technology, xuzhou 2.1.1., China 2.college of mechanical and electrical engineering, China {1. of mining & Technology, xuzhou 2.1.1., China 3 Biotribology Center, State Key Laboratory of Tribology, xuzhou 2.1.1., China Institute of Tribology and Reliability engineering China University of Mining & Technology Xuzhou 221116 China college of {1. and {2. engineering China University of Mining & Technology Xuzhou 221116 China Biotribology Center State Key Laboratory of Tribology Xuzhou 221116 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

Parameters Relevant to Bubble Detachment when Gas-injecting into Polymer Melt Flow Field

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Journal of Wuhan university of Technology(Materials Science) 2005年第1期20卷 68-71页

作者：陈再良 college of {1. and {2. engineering Soochow University Suz hou 215021 China

The bubble deformation processes were reported when gas was injected into polyme r melt flow field in another paper, the experiments showed that the deformation was severely affected by the volume of the bubble, and in turn, for the different bubbles, several different deformation processes were presented d uring their movement along the flow channel. In addition, we could find that the magnitude of the bubble volume was dependent upon the pressure difference of th e gas injection pressure and the melt pressure. In this paper, more experimental conditions were changed to investigate the parameters relevant to the detachmen t of bubbles from the injection nozzle. The experimental results show that the p ressure difference, the melt flow velocity as well as the melt pressure were all critical for the parameters, such as the bubble detachment time, the maximum bu bble diameters and the magnitude of the bubble volume. The morphology changes of bubble were very large when the flow field was abruptly changed, and the situat ions were more complicated.

关键词： bubble morphology detachment time geometry parameters flow field

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 {1. of mining and Technology, xuzhou 2.1.1., P. R. China2. School of mechanical and electrical engineering, China {1. of mining and Technology, xuzhou 2.1.1., P. R. China3. Biotribology Center, National Key Laboratory of Tribology, Tsinghua {1., Beijing 1.0083, P. R. China [a]School of Materials Science and engineering China University of Mining and Technology Xuzhou 221116 P. R. China [b]School of Mechanical and Electrical Engineering China University of Mining and Technology Xuzhou 221116 P. R. China [c]Biotribology Center National Key Laboratory of Tribology Tsinghua University Beijing 100083 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

Tribological Properties of Dimpled Surface Alloying Layer on Carbon Steel

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Journal of Wuhan university of Technology(Materials Science) 2009年第2期24卷 218-222页

作者：万轶 Department of Materials Science & engineering Nanjing University of Science and Technology Department of mechanical and {1. {2. Yingtian College

The effect of surface structure and coating on tribological properties of 45^# carbon steel disc was analyzed. A Nd：YAG laser was used to generate rnicrodirnples on steel surfaces. Dimples with diameter of 1.0 rn and depth of 50 rn were distributed in an orbicular array on disc surface. Then the alloying element Mo was sputtered to 45# carbon steel disc surface by means of double glow plasma technology. Diffusion Mo alloying layer with 30min thickness and high hardness up to 0.02. was formed on the disc surface. Tribological experiments of three types samples （smooth, texturing and texturing＋alloying） were conducted with a pin-on-disc tribometer. It is found that the dimpled-samples are most effective for reducing friction in comparison with smooth steel surthces, improving the lubricating state from boundary to hydrodynamic region.

关键词： laser surface texturing double glow plasma surface alloying technology carbon steel tribological performance lubricating state

Study on Theory and Application of the Energy Method used for Analyzing Compressive Instability in Sheet Forming

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厦门大学学报（自然科学版） 2002年第S1期41卷 126-127页

作者： XIONG Zhi-qing 1. XIE Lan-sheng 2.(1. Department of {2. {1., Nanjing Institute of Techno logy, Nanjing 2.0}01., China 2. college of {2. and electrical {1., Nanjing university of Aer onautics and Astronautics, Nanjing 2.0}01., China)

It is pointed out that there was serious weakness w he n using the energy method for studying compressive plastic instability in sheet forming in the past. Where applying the deduced instability strengths to relativ e engineering analysis, theoretical solutions were away from practices. Its basi c reason is that simplified process in mathematical analysis of elastic bending energy was completely applied to that of plastic bending energy. Where the cambe r expressed by function of displacement normal to a plate was approximated to re alistic deflective camber, the displacement of deflected plate to compressed dir ection was neglected. With the aid of the improved instability strengths, the pr edictions on both critical buckling dimension of blank in cup deep-drawing with out blankholder through cylindrical die or conical die and the minimum blankhold er pressure to prevent buckling under constant load are universally in agreement with both experimental results and experiential data. On the bases of above-mentioned improvement, the approximate expressions for bo th the curvature and the twist used in equation of the energy of elastic bending are also ameliorated. Thus the obtained general equations for both the energy a nd the work done by internal force in plastic bending of a plate are more precis e than before. In the analyses of plastic buckling of shell with bending moment, the effect of bending moment is considered through the work done by simulative bending for ce. The method proposed in this paper can not only simplify analyses but also ge t practical result.

关键词： sheet forming deep-drawing buckling energy me thod

Morphology and reaction force of toes of geckos freely moving on ceilings and walls

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Science China(Technological Sciences) 2010年第6期53卷 1688-1693页

作者： WANG ZhouYi1.2.GU WenHua1.2.WU Qiang1.2.JI AiHong1.& DAI ZhenDong1.1.Institute of Bio-inspired Structure and Surface engineering,Nanjing {1. of Aeronautics and Astronautics,Nanjing 2.0}01.,China 2.college of mechanical and electrical engineering,Nanjing {1. of Aeronautics and Astronautics,Nanjing 2.0}01.,China 1. Institute of Bio-inspired Structure and Surface engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China2. College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

The 3-dimensional interactions between toes of a gecko and substrates (ceilings or walls) were measured when it moves on ceilings or walls by using a 3-dimensional force measuring array,and the correspondent morphology of the gecko toes was recorded by a high speed *** study aims to understand the relationship between adhesive and shear forces generated by the toes of the gecko and the locomotion behavior when it walks on walls and *** showed that shear force is along the toe-only 1..6° and 3.1. away from the toe for wall-climbing and ceiling-crawling,respectively while the adhesion is big enough to balance the body weight and *** shear forces generated by the first and the fifth toes are in opposite directions;this redundant force increases the reliability of adhesion and stability of *** support angles of toes are equal approximately for ceiling-crawling and *** study greatly inspires the design of a gecko-like robot.

关键词： reaction force of toe morphometrics ceiling redundant force gecko-like robot

Nanostructured Sulfide Composite Coating Prepared by Atmospheric Plasma Spraying

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材料工程 2006年第Z1期34卷 281-284页

作者： GUAN Yao-hui~1.XU Yang~1.ZHENG Zhong-yu~2.TONG Xiao-hui~2.1.engineering {1. of China Agricultural university,Beijing 1.0083,China 2.Beijing Research Institute of mechanical & electrical Technology,Beijing 1.0083,China) engineering {1. China Agricultural University Beijing 100083 China Beijing Research Institute of mechanical and {1. Technology Beijing 100083 China

Nanostructured FeS-SiC coating was deposited by atmospheric plasma spraying（APS）.The microstructure and phase composition of the coating were characterized with SEM and XRD,*** addition,the size distribution of the reconstituted powders and the porosity of the coating have been *** was found that the reconstitiuted powers with sizes in the range of 2. to 80 μm had excellent flowability and were suitable for plasma spraying *** as-sprayed FeS-SiC composite coating exhibited a bimodal distribution with small grains（30～80nm） and large grains（1.0～2.0nm）.The coating was mainly composed of FeS and SiC,a small quantity of Fe1.xS and oxide were also *** porosity of the coating was approximately 1.%.

关键词： plasma spraying nanostructured FeS-SiC composite coating