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Quasi-static Analysis of Thrust-loaded Angular Contact Ball Bearings Part Ⅱ:Results and Discussion

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Chinese Journal of Mechanical Engineering 2012年第1期25卷 81-87页

作者： CHEN Wenhua1,2,MA Zikui1,GAO Liang1,LI Xinglin3,and PAN Jun2 1 Institute of Mechanical Design,Zhejiang university,Hangzhou 310027,China 2 Institute of Mechanical Design and manufacturing,Zhejiang Sci-Tech university,Hangzhou 310018,China 3 State Testing Laboratory of Hangzhou Bearing Test & research center,Hangzhou 310022,China 1. Institute of Mechanical Design Zhejiang University Hangzhou 310027 China 2. Institute of Mechanical Design and manufacturing Zhejiang Sci-Tech University Hangzhou 310018 China 3. State Testing Laboratory of Hangzhou Bearing Test & research center Hangzhou 310022 China

Ball bearings are widely employed mechanical components characterized by high precision and quality,and usually play important roles in various rotary machines and *** advanced applications require a deep understanding of their various kinematic and tribological characteristics that are essential to predict the fatigue endurance,relieve the vibration and minimize the power dissipation of ball bearings in particular *** angular contact ball bearing under a specified operating condition is simulated with the quasi-static/creepage analytical model proposed in the preceding *** results demonstrate that the ball bearing is a statically determinate *** the balls spin on both inner and outer races means the ball is controlled by neither the inner nor the outer *** friction between the ball and raceway renders the inner and outer contact angles *** larger the coefficient of friction is,the larger the angle *** tangential traction perpendicular to the rolling direction due to the spin induces a gyro-like rotation of the ball with respect to the raceway even if no inertial effects are *** tangential elastic compliance of contacting surfaces gives rise to locked areas within the contact patch and transforms the sliding lines from circles into *** differential slip due to the close conformity of the ball and raceway makes the sliding and traction distributions asymmetric,which will influence the location of the spinning center of the ball with respect to the *** quasi-static/creepage model can be used to reveal the operating behaviors of ball bearings running under steady conditions and to optimize the design of ball bearings for specific applications.

关键词： ball bearing quasi-static creepage differential slip tangential elastic compliance

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CM elliptic curves and p-adic valuations of their L-series at s=1

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Progress in Natural Science:Materials International 2002年第10期12卷 67-70页

作者： QIU Derong(center for advanced Study, Tsinghua university, Beijing 100084, China) Tsing Hua Univ Ctr Adv Study Beijing 100084 Peoples R China

For rational integers γ and λ, consider two families of elliptic curves y2 = x3 - D1γx and y2 = x3 - 2433D2λ over fields (?) ( (-1)~1/2) and (?) ((- 3)1/2) respectively. General formulae expressed by Weierstrass (?)-functions are given for special values of Hecke L-series attached to such elliptic curves. The uniform lower bounds of 2-adic and 3-adic valuations of these values of Hecke L-series as well as global criteria for reaching these bounds are obtained. Moreover, when γ = 2 and λ = 2, 4, further results of 2-adic and 3-adic valuations are obtained for the corresponding curves in more general case of D1 and some restricted D2 respectively. These results are consistent with the predictions of the conjecture of Birch and Swinnerton-dyer, and greatly develop and generalize some results in recent literature for more special cases.

关键词： elliptic curve L-series complex multiplication Birch and Swinnerton-dyer conjecture.

Mesh theory of angle modified dual tori double-enveloping toroidal worm drive

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Science China(Technological Sciences) 2010年第7期53卷 1913-1927页

作者： ZHAO YaPing1, SU DaiZhong2, ZHANG Zhao1, WEI WenJun3 & DONG XueZhu3 1 College of Machinery and Automation, Wuhan university of Science and Technology, Wuhan 430081, China 2 advanced Design and manufacturing Engineering center, Nottingham Trent university, Nottingham NG1 4BU, UK 3 College of Engineering, China Agricultural university, Beijing 100083, China 1. College of Machinery and Automation Wuhan University of Science and Technology Wuhan 430081 China2. Advanced Design and Manufacturing Engineering Center Nottingham Trent University Nottingham NG1 4BU UK3. College of Engineering China Agricultural University Beijing 100083 China

In this paper, the meshing theory of the angle modified hourglass worm drive is enriched and developed. The ordinary condition of the angle modification is derived and the physical significance of the modification is interpreted. A normal section methodology is proposed for meshing analysis, which can be used to compute the normal distance near a singular meshing point of a conjugate surface couple. By means of the method and after analyzing the normal transversals, it is specified that the worm helicoid, the nominal former contact zone and the new contact zone intersect each other along the locus of singular points of the instantaneous contact lines of an angle-modified worm pair. As a result, it is explained clearly that those three osculate each other but the osculations are different in degree. Moreover, the mechanism of removing the twice-contacted zone from the worm gear tooth surface is clarified and the reason of shortening the worm working length is also elucidated. With the help of the theory described in the present paper and the thorough and systematic research on the relevant meshing characteristics, the angle modified dual tori double-enveloping toroidal worm drive has been shown to be an excellent new-fashioned hourglass worm set.

关键词： hourglass worm angle modification double-enveloping osculation normal transversal

La2O3-Al2O3-SiO2 glass-infiltrated 3Y-TZP all-ceramic composite for the dental restorative application

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Progress in Natural Science:Materials International 2012年第3期22卷 224-230页

作者： Shenyong Shi a, Qinghong Zhang b, Hongzhi Wang a, Yaogang Li b a State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua university, Shanghai 201620, PR China b Engineering research center of advanced Glasses manufacturing Technology, MOE, Donghua university, Shanghai 201620, PR China [a] State Key Laboratory for Modi?cation of Chemical Fibers and Polymer Materials Donghua University Shanghai 201620 PR China [b] Engineering research center of advanced Glasses manufacturing Technology MOE Donghua University Shanghai 201620 PR China

The 3 mol% yttria stabilized tetragonal zirconia polycrystals (3Y-TZP) powder had three particle size distributions, while the fine one was lower than 100 nm. The 3Y-TZP compact was prepared by dry-pressing under pressures ranged from 10 to 30 MPa and then presintered at 1250 ℃ for 2 h. The matrix dry-pressed under the pressure of 20 MPa had a porosity of 16.7% and could be easily processed by computer aided design and computer aided manufacturing (CAD/ CAM), and which had been infiltrated by the La2O3-Al2O3-SiO2 glass at 1200 ℃ for 4 h. The flexural strength and fracture toughness of the composite were 710.7 MPa and 6.51 MPa m1/2, respectively. The low shrinkage (0.3%) of the composite can satisfy the net-shape fabrication standard. XRD results illustrated that zirconia in the La2O3-Al2O3-SiO2 glass-infiltrated 3Y-TZP all-ceramic composite was mainly in the tetragonal phase. SEM and EDS results indicated that the pores of the matrix were almost filled by the La2O3-Al2O3-SiO2 glass.

关键词： 3Y-TZP Glass-infiltrated Composite Mechanical properties

Mechanical Property and Microstructural Characterization of C-Mn-Al-Si Hot Dip Galvanizing TRIP Steel

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Journal of Iron and Steel research International 2012年第8期19卷 29-36页

作者： JIANG Hai-tao1, DING Wei1,2, TANG Di1, HUANG Wei1 (1. National Engineering research center for advanced Rolling Technology, university of Science and Technology Beijing, Beijing 100083, China 2. School of Material and Metallurgy, Inner Mongolia university of Science and Technology, Baotou 014010, Inner Mongolia, China) [a] National Engineering research center for advanced Rolling Technology University of Science and Technology Beijing Beijing 100083 China [b] School of Material and Metallurgy Inner Mongolia University of Science and Technology Baotou 014010 Inner Mongolia China

Mechanical properties and microstructure in high strength hot dip galvanizing TRIP steel were investigated by optical microscope (OM), transmission electron microscope (TEM), X-ray diffraction (XRD), dilatometry and mechanical testing. On the heat treatment process of different intercritical annealing (IA) temperatures, isothermal bainitic transformation (IBT) temperatures and IBT time, this steel shows excellent mechanical properties with tensile strength over 780 MPa and elongation more than 22%. IBT time is a crucial factor in determining the mechanical properties as it confirms the bainite transformation process, as well as the microstructure of the steel. The microstructure of the hot dip galvanizing TRIP steel consisted of ferrite, bainite, retained austenite and martensite during the short IBT time. The contents of ferrite, bainite, retained austenite and martensite with different IBT time were calculated. The results showed that when IBT time increased from 20 to 60 s, the volume of bainite increased from 14.31% to 16.95% and the volume of retained austenite increased from 13.64% to 16.28%; meanwhile, the volume of martensite decreased from 7.18% to 1.89%. Both the transformation induced plasticity of retained austenite and the hardening of martensite are effective, especially, the latter plays a dominant role in the steel containing 7.18% martensite which shows similar strength characteristics as dual-phase steel, but a better elongation. When martensite volume decreases to 1.89%, the steel shows typical mechanical properties of TRIP, as so small amount of martensite has no obvious effect on the mechanical properties.

关键词： TRIP steel isothermal bainitic transformation martensite mechanical property

Phenomenon of “contact guidance” on the surface with nano-micro-groove-like pattern and cell physiological effects

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Chinese Science Bulletin 2009年第18期54卷 3200-3205页

作者： ZHOU Feng 1,2, YUAN Lin 1,3, HUANG He 1,2 & CHEN Hong1,2 1 State Key Laboratory of advanced Technology for Materials Synthesis and Processing, Wuhan 430070, China 2 School of Materials Science and Engineering, Wuhan university of Technology, Wuhan 430070, China 3 Biomedical Materials research center, Wuhan university of Technology, Wuhan 430070, China State Key Laboratory of advanced Technology for Materials Synthesis and Processing Wuhan 430070 China School of Materials Science and Engineering Wuhan University of Technology Wuhan 430070 China Biomedical Materials research center Wuhan University of Technology Wuhan 430070 China

The topography of material surface has important influence on cell behavior and physiological functions. Groove-like pattern has drawn much attention among various patterns, due to the phenomenon of "contact guidance" induced by this kind of topography. This review mainly focuses on "contact guidance" formation as well as its influence on cell behavior and physiological effects. The possible mechanisms of "contact guidance" formation were discussed. The research trend and the potential applications were also suggested.

关键词：细胞行为生理功能材料表面逻辑效应触指纳米微米生理效应

Present Status of EUV Interferometer Development at the research center for Soft X-ray Microscopy

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光学精密工程 2001年第5期9卷 405-410页

作者： Masaki Yamamoto, Tadashi Hatano, Minaji Furudate (research center for Soft X-ray Microscopy, Institute of Multidisciplinary research for advanced Materials, Tohoku university, Japan) Tohoku university 日本

A new interferometer for extreme ultraviolet (EUV) radiation with a laser produced plasma (LPP) laboratory source is under construction. The LPP source is operated with a Sn solid rod target on which pulsed YAG laser is focused to produce high temperature plasma emitting EUV radiation. The source is equipped with a newly designed debris stopper protecting a condenser multilayer mirror from the particle debris of the target. The condenser mirror focuses the light onto an EUV beam-splitter to form transmitted and reflected paths for producing interference fringes of a sharing type. The optical configuration is of a common path based on a triangular path type with a focusing at the beam-splitter, which is enabled to produce fringes by a low coherence radiation with a standard optical quality beam-splitter. The fringes are recorded by an imaging plate with pixels as small as 25μm. The dynamic range of linearity in detection of the EUV light was found to be more than 10 4 with sensitivity of 10 4 photons/pixel, enough for the purpose of interferogram recording, possibly with one laser shot.

关键词： soft X-ray interferometers multilayer mirrors figure error imaging optics

Synthesis of dental resins using diatomite and nano-sized SiO2 and TiO2

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Progress in Natural Science:Materials International 2012年第2期22卷 94-99页

作者： Xiaoli Miao a,Meifang Zhu a,Yaogang Li b,Qinghong Zhang b,Hongzhi Wang a a State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua university,Shanghai 201620,China b Engineering research center of advanced Glasses manufacturing Technology,MOE,Donghua university,Shanghai 201620,China [a] State Key Laboratory for Modification of Chemical Fibers and Polymer Materials Donghua University Shanghai 201620 China [b] Engineering research center of advanced Glasses manufacturing Technology MOE Donghua University Shanghai 201620 China

The mechanical properties of dental composites were improved by porous diatomite and nano-sized silica(OX-50)used as *** resin composites,filled with silanized OX-50 and silanized diatomite(40:60 wt/wt),presented the best flexural strength(133.1 MPa),elastic modulus(9.5 GPa)and Vickers microhardness(104.0 HV).Besides these,TiO2 nanoparticles were introduced to tune the dental resin composites colours which were valued by the CIE-Lab *** colour parameters(L*,a*,b*)showed that the colour changes of resin composites could be perceived obviously,when 300-400 nm TiO2 particles were introduced as *** resin composite,filled with 0.5 wt%TiO2,exhibited both clear discolouration(DE * =3.22)and high mechanical *** scanning electron microscope(SEM)equipped with an energy dispersive X-ray(EDX),the titanium elemental mapping results indicated that the TiO2 particles were distributed evenly in the prepared dental composites.

关键词： Dental resin composites TiO2 Diatomite Colour change Optical properties

One-dimensional nonlinear consolidation of soft clay with the non-Darcian flow

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Journal of Zhejiang university-Science A(Applied Physics & Engineering) 2013年第6期14卷 435-446页

作者： Chuan-xun LI Kang-he XIE Faculty of Civil Engineering and Mechanics Jiangsu University research center of Coastal and Urban Geotechnical Engineering Zhejiang University

Based on the non-Darcian flow law described by exponent m and threshold gradient i 1 under a low hydraulic gradient and the classical nonlinear relationships e-lgσ′ and e-lgk v (Mesri and Rokhsar, 1974), the governing equation of 1D nonlinear consolidation was modified by considering both uniform distribution of self-weight stress and linear increment of self-weight stress. The numerical solutions for the governing equation were derived by the finite difference method (FDM). Moreover, the solutions were verified by comparing the numerical results with those by analytical method under a specific case. Finally, consolidation behavior under different parameters was investigated, and the results show that the rate of 1D nonlinear consolidation will slow down when the non-Darcian flow law is considered. The consolidation rate with linear increment of self-weight stress is faster than that with uniform distribution one. Compared to Darcy's flow law, the influence of parameters describing non-linearity of soft soil on consolidation behavior with non-Darcian flow has no significant change.

关键词： Non-Darcian flow Nonlinear consolidation Time-dependent loading Uniform distribution of self-weight stress Linear increment of self-weight stress