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Constructing a biomimetic robust bi-layered hydrophilic lubrication coating on surface of silicone elastomer

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Friction 2022年第7期10卷 1046-1060页

作者： Luyao GAO Xiaoduo ZHAO Shuanhong MA Zhengfeng MA Meirong CAI yong-Min LIANG feng zhou School of Chemistry and Chemical Engineering Lanzhou UniversityLanzhou 730000China Lanzhou Institute of Chemical Physics Chinese Academy of SciencesLanzhou 730000China

Silicone elastomers-based materials have been extensively involved in the field of biomedical devices,while their use is extremely restricted due to the poor surface lubricity and inherent *** paper describes a novel strategy for generating a robust layered soft matter lubrication coating on the surface of the polydimethylsiloxane(PDMS)silicone elastomer,by entangling thick polyzwitterionic polyelectrolyte brush of poly(sulfobetaine methacrylate)(PSBMA)into the sub-surface of the initiator-embedded stiff hydrogel coating layer of P(AAm-co-AA-co-HEMA-Br)/Fe,to achieve a unified low friction and high load-bearing ***,the stiff hydrogel layer with controllable thickness is covalently anchored on the surface of PDMS by adding iron powder to provide catalytic sites through surface catalytically initiated radical polymerization(SCIRP)method and provides high load-bearing capacity,while the topmost brush/hydrogel composite layer is highly effective for aqueous *** synergy effects are capable of attaining low friction coefficient(COFs)under wide range of loaded condition in water environment with steel ball as sliding ***,the influence of mechanical modulus of the stiff hydrogel layer on the lubrication performance of layered coating is investigated,for which the COF is the lowest only when the modulus of the stiff hydrogel layer well matches the PDMS ***,the COF of the modified PDMS could remain low friction(COF<0.05)stably after encountering 50,000 sliding cycles under 10 N ***,the surface wear characterizations prove the robustness of the layered lubricating *** work provides a new route for engineering lubricious silicon elastomer with low friction,high load-bearing capacity,and considerable durability.

关键词： surface modification silicone elastomer layered lubrication coating hydrogels polyzwitterionic brush

Microstructure and properties of W-4.9Ni-2.1Fe heavy alloy with Dy2O3 addition

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Rare Metals 2019年第8期38卷 746-753页

作者： Yuan-feng Xie Liang-Liang zhou Xiao-yong Zhang Xiao-Xian Li Zeng-Lin zhou Xue-Hui Zhang Institute of Engineering and Technology General Research Institute for Nonferrous Metals Beijing 100088China School of Materials Science and Engineering Jiangxi University of Science and Technology Ganzhou 341000China

The W-4.9 Ni-2.1 Fe-xDy2 O3 heavy alloy was fabricated by high-energy ball milling and spark plasma sintering(SPS)technique,and the microstructure,mechanical and friction behavior and anti-corrosion ability were investigated by scanning electron microscope(SEM),Rockwell hardness tester,X-ray diffraction(XRD),reciprocating friction and wear tester,electrochemical station,*** results show that the trace Dy2 O3 particles,which mainly distributes in the W-M(tungsten-matrix)interface and the tungsten matrix phase,can dramatically decrease the tungsten grain size and the amount of O and P impurities aggregating in the interface,promote the γ-(Ni,Fe)bonding phase and tungsten particles uniform distribution,and increase the relative density,hardness,and wear and corrosion resistance *** the excessive Dy2 O3 addition can make the inhibition effect weaken,resulting in the decrease in the comprehensive performances of the ***,the amount of Dy2 O3 should be *** the adding amount of Dy2 O3 particles is 0.7 wt%,the comprehensive performances of the heavy alloy are the best.

关键词： Dysprosium oxide W-4.9Ni-2.1Fe alloy Spark plasma sintering Mechanical property Anticorrosion ability

How the radial gap affects the runner’s hydrodynamic damping characteristic of a pump-turbine:A physical experiment on a rotating disc

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Journal of Hydrodynamics 2023年第4期35卷 736-745页

作者： yong-shun Zeng Xin Qi Mian-mian Bai Ling-jiu zhou Zhi-feng Yao College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China BAPTEEC LTD Beijing100176China Shanxi Province Institute of Water Resources and Electric Power Investigation and Design Xi’an710001China Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System Beijing100083China

Clarifying how radial gap affects the vibration characteristic of a disc-like structure is of importance in engineering applications,such as in evaluating the operational stability of a runner of a pump *** the present investigation,the runner is simplified as a disc,and a physical experiment is designed on it with variable radial gaps to measure the vibration characteristics,especially by considering *** frequency peaks for the diametrical mode are generated due to the rotation,and those with lower and higher frequencies are defined as positive and negative modes,*** frequency difference between positive and negative modes increases linearly with the increasing rotating speed,and a linear function is captured to describe the relationship between natural frequency and rotating *** the radial gap,its increase causes a slight increase in the natural frequencies but results in a significant reduction in the hydrodynamic damping *** in the smaller radial gap conditions,such as when the relative radial gap increases from 0.67%to 3.3%,the reduction in hydrodynamic damping ratio reaches 31.52%.From the perspective of suppressing the resonance amplitude,reducing the radial gap of a runner is recommended due to the mechanism of increasing hydrodynamic damping.

关键词： Rotating disc radial gap rotating speed natural frequency hydrodynamic damping

NUMERICAL SOLUTION OF 2-D INCOMPRESSIBLE VISCOUS FLOW WITH HIGH ORDER COMPACT SCHEME USING DOMAIN DECOMPOSITION AND MATCHED METHOD

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Journal of Hydrodynamics 2001年第4期13卷 79-82页

作者： Ren, An-Lu Lu, Xiao-Dong Zou, Jian-feng zhou, yong-Xia Dept. of Mech. Zhejiang Univ. Hangzhou 310027 China

This paper presents a high-accuracy method for solving 2-D incompressible viscous N-S equations in tensor forms. A domain decomposition method was used to divide the computational domain into several regular blocks with the overlapping grid in order to transfer data between sub-domains and to remove numerical singularity caused by domain decomposition. Using the method and algorithm presented above, the flow passing an ellipse was computed and the formation and evolution of the vortex shedding was successfully simulated.

关键词： Computational fluid dynamics Computational methods Incompressible flow Navier Stokes equations

Effect of Magnesium on Inclusion Formation in Ti-Killed Steels and Microstructural Evolution in Welding Induced Coarse-Grained Heat Affected Zone

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Journal of Iron and Steel Research International 2009年第1期16卷 69-74页

作者： CHAI feng YANG Cai-fu SU Hang ZHANG yong-quan XU zhou Central Iron and Steel Research Institute Beijing 100081 China Shanghai Jiaotong University Shanghai 200030 China

Effects of Mg on the chemical component and size distribution of Ti-bearing inclusions favored grain refinement of the welding induced coarse-grained heat affected zone （CGHAZ）, with enhanced impact toughness in Ti-killed steels, which were examined based on experimental observations and thermodynamic calculations. The results indicated that the chemical constituents of the inclusions gradually varied from the Ti-O＋Ti-Mg-O compound oxide to the Ti-Mg-O＋MgO compound oxide and the single-phase MgO, as the Mg content increased from 0.002 3M to 0.006%. A trace addition of Mg （approximately 0. 002%） led to the refinement of Ti-bearing inclusions by creating the Ti-Mg-O compound oxide and provided favorable size distribution of the inclusions for acicular ferrite transformation with a high nucleation rate in the CGHAZ, and a high volume fraction of acicular ferrite was obtained in the CGHAZ with enhanced impact toughness. Otherwise, a high content of Mg （approximately 0. 006%） produced a single-phase MgO, which was impotent to nucleate an acicular ferrite, and a microstructure comprised of a ferrite side plate and a grain boundary ferrite developed in the CGHAZ. The experimental results were confirmed by thermodynamic calculations.

关键词： non-metallic inclusion magnesium acicular ferrite coarse-grained heat affected zone (CGHAZ)

Determination of Hydrocarbon Charging History by Diagenetic Sequence and Fluid Inclusions:A Case Study of the Kongquehe Area in the Tarim Basin

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Acta Geologica Sinica(English Edition) 2015年第3期89卷 876-886页

作者： WANG Bin feng yong ZHAO yongqiang zhou Yushuang LUO Yu ZHANG Genfa Wuxi Research Institute of Petroleum Geology SINOPEC School of Geosciences Yangtze University Research Institute of Exploration and Development Northwest Oilfield Branch CompanySINOPEC

Petrographic analysis of hydrocarbon inclusions in reservoirs is the basis and prerequisite for study of hydrocarbon charge history using fluid inclusion *** from Silurian reservoirs in the Kongquehe area were studied with microscopy,cathode luminescence and scanning electron microscopy,and the paragenetic sequence of diagenetic events was *** and oil inclusions were found in four different occurrences,i.e.,① in healed cracks in detrital quartz grains,② in quartz overgrowths that were formed relatively early in diagenesis,③ in healed cracks crosscutting quartz overgrowths and detrital quartz,and ④ in paragenetically late calcite *** bitumens were found in intergranular pores and in late fractures,whereas gas inclusions occur in healed cracks crosscutting quartz overgrowths and detrital *** homogenization temperatures of aqueous（Th_（aq）） and oil incluisons（Th_0） within individual fluid inclusion assemblages are very consistent,suggesting that the microthermometric data are *** Th_（aq） values are generally larger than Th_0,indicating the oil charging events took place at significant *** results suggest that there were at least two episodes of hydrocarbon charging in the Kongquehe area：the early hydrocarbon charging occurred in late Caledonian,dominated by oil,and the late hydrocarbon charging occurred in the Yanshan-Himalayan,first by oil and then *** addition,two episodes of hydrocarbon reservoir adjustment and destruction occurred in the Hercynian and Himalayan,respectively,forming solid bitumen.

关键词： Fluid inclusion diagenetic sequence hydrocarbon charge history Kongquehe area TarimBasin

Chiral surface waves supported by biaxial hyperbolic metamaterials

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Light(Science & Applications) 2015年第1期4卷 187-191页

作者： Wen-Long Gao feng-zhou Fang yong-Min Liu Shuang Zhang State Key Laboratory of Precision Measuring Technology and Instruments Tianjin UniversityTianjin 300072China School of Physics&Astronomy University of BirminghamBirmingham B152TTUK Department of Mechanical and Industrial Engineering Northeastern UniversityBostonMA 02115USA Department of Electrical and Computer Engineering Northeastern UniversityBostonMA 02115USA

We discover a new kind of surface wave on biaxial hyperbolic metamaterial,which,in the k-space,connects the two diabolical points(or conical singularities)of the equifrequency ***,the propagation of such surface wave is found to be sensitive to the refractive index of the surrounding dielectric medium,showing a convex,concave or flat phase front when the refractive index is ***,the surface wave shows an elliptically polarized state,in which helicity is dependent on the propagation *** feature can be utilized for the spin-controllable excitation of surface waves,opening a gateway towards integrated photonic circuits with reconfigurable functionalities.

关键词： metamaterial spin orbital coupling surface wave

Hand-Held Surgical Instrument with the Function of Self-Locking for Minimally Invasive Surgery

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Journal of Beijing Institute of Technology 2019年第3期28卷 561-569页

作者： Mei feng Haijun Zhang Xiaoqin zhou Chang Wang yong Hu College of Mechanical Science and Engineering Jilin University

In order to improve the flexibility of the surgical instruments, a wire-driven wrist-like structure is proposed in this paper. The instrument has three degrees of freedom (DOFs) of rotation, yaw, opening and closing. Furthermore, we also acknowledge no coupling motion for each DOF. Moreover, the self-locking motion contributes to sustaining joint posture under external force. A static analysis for the end effector was conducted using the ANSYS software. At the end of this paper, a series of experiments for the prototype was performed. The results revealed that for the same surgical task, the proposed instrument had higher flexibility and the completion time of the operation tasks was obviously less than that of the traditional instrument. The results of the self-locking and operating force test showed that the surgical instruments perform well in maintaining joint posture under the force of 8.2N. The proposed surgical instrument meets the requirements of minimally invasive surgery (MIS).

关键词： minimally invasive surgery (MIS) surgical instrument structure design

A REMARK ON DUALITY FOR THE SUM OF CONVEX FUNCTIONS IN GENERAL BANACH SPACES

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Chinese Annals of Mathematics,Series B 1998年第3期19卷 249-254页

作者： zhou feng E China Normal Univ Dept Math Shanghai 200062 Peoples R China

The author gives a new proof of Attouch Brezis′ theorem concerned with the duality for the sum of convex functions in general Banach spaces, and gives also some sufficient conditions for the difference of two close... 详细信息

关键词： Conjugate convex function Asymptotic cone Infimal convolution