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Chinese j.urnal of Aeronautics 2017年第2期30卷 827-835页

作者： Zhang Wenhu Deng sier Chen Guoding Cui Yongcun School of Mechatronics Engineering Northwestern Polytechnical University Xi'an 710071 China School of Mechatronics Engineering Henan University of Science and Technology Luoyang 471003 China Collaborative Innovation Center of Maj.r Machine Manufacturing in Liaoning Dalian 116024 China

In this paper,the formulas of elasto-hydrodynamic traction coefficients of three Chinese aviation lubricating oils,4109,4106 and 4050,were obtained by a great number of elastohydrodynamic traction *** nonlinear dynamics differential equations of high-speed angular contact ball bearing were built on the basis of dynamic theory of rolling bearings and solved by Gear Stiff（GSTIFF） integer algorithm with variable *** impact of lubricant traction coefficient on cage＇s dynamic characteristics in high-speed angular contact ball bearing was investigated,and Poincare map was used to analyze the impact of three types of aviation lubricating oils on the dynamic response of cage＇s mass *** then,the period of dynamic response of cage＇s mass center and the slip ratio of cage were used to assess the stability of cage under various working *** results of this paper provide the theoretical basis for the selection and application of aviation lubricating oil.

关键词： Dynamic characteristic High-speed angular contact ball bearing Lubricant traction coefficient Poincare map Stability

Experimental study on impact of roller imbalance on cage stability

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Chinese j.urnal of Aeronautics 2021年第10期34卷 248-264页

作者： Yongcun CUI sier DENG Kaiwen DENG Hui LIAO Wenhu ZHANG School of Information Engineering Henan University of Science ami TechnologyLuoyang 471003China Post-Doctoral Workstation Bcihucm Technology Group Co..LtdTaizhou 318000China School of Mcchatronics Engineering Henan University of Science and TechnologyLuoyang 471003China School of Mechanical Engineering Northwestern Po/ytechnical UniversityXi'an 710071China

This study presents a method for measuring the imbalance in a small-sized cylindrical *** roller imbalance was calibrated on the built static-pressure-air flotation measurement *** impact of the roller imbalance on the dynamic characteristics of a cage were then studied on the aero-bearing test *** displacement spectrums with different roller imbalance of the obtained cage orbits under various bearing speed and radial load were used to evaluate the cage *** results show that the cage cannot form a stable operating state at a lower bearing speed with or without the unbalanced *** cage with balanced rollers gradually develops stable motion with the increase of the bearing *** existence of a small roller imbalance causes the stability of the cage to *** an increase in the bearing speed and radial load,the cage with the unbalanced rollers runs unsteadily accompanied by a high-frequency vibration when the roller imbalance is large *** vibration amplitude of the cage in the horizontal direction is greater than that in the vertical direction during an unstable operation,which is similar in the stable status.

关键词： Cage orbits Cage stability Experimental study High-speed cylindrical roller bearing Roller imbalance Spectrum Vibration

Cage slip characteristics of a cylindrical roller bearing with a trilobe-raceway

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Chinese j.urnal of Aeronautics 2018年第2期31卷 351-362页

作者： sier DENG Yuj.a LU Wenhu ZHANG Xue SUN Zhenwei LU School of Mechanical Engineering Henan University of Science and Technology Luoyang 471003 China Collaborative Innovation Center of Maj.r Machine Manufacturing in Liaoning Dalian 116024 China Patent Examination Cooperation Center of the Patent Office SIPO Henan Zhengzhou 450002 China School of Mechanical Engineering Northwestern Polytechnical University Xi'an 710071 China Technology Center of LUO YANG L YC BEARING CO. LTD Luoyang 471003 China

Based on dynamic analysis of rolling bearings, the nonlinear dynamic differential equations of a cylindrical roller bearing with a trilobe-raceway were established and solved by the GSTIFF（gear stiff） integer algorithm with a variable step. The influences of structural parameters and the tolerance of the trilobe-raceway, working conditions of the bearing, and the outer ring installation method on cage slip characteristics were investigated. The results show that：（i） The cage slip ratio and bearing rating life of a cylindrical roller bearing with a trilobe-raceway would reduce when the low-radius（radius of the outer raceway contour at the lowest point） and D-value（difference value between the high and low points of the outer raceway contour） decrease, and the former（low-radius） contributes more significantly.（ii） The cage slip ratio of a cylindrical roller bearing with a trilobe-raceway rises with the increase of the bearing speed, and decreases with the increase of the radial force; the variation range increases with the increase of the low-radius.（iii） When the installation angle of the outer ring increases in a period, the cage slip ratio remains unchanged while the bearing rating life rises up a little. Therefore, when installing a cylindrical roller bearing with a trilobe-raceway, the location of the maximum radius shall be under that of the radial force to improve the bearing rating life.（iv） With the increase of the roundness of the base circle where the radius of the lowest points of the trilobe-raceway contour locates, the cage slip ratio rises gradually and the bearing rating life decreases.

关键词： Bearing rating life Cage slip ratio Dynamics Raceway contour Trilobe-raceway

Pressure performance for a thin-walled ring and turbulent-j.t orifice modeled elastic squeeze film damper

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Chinese j.urnal of Aeronautics 2022年第11期35卷 235-251页

作者： Xiaomin YANG Haisheng YANG Yongcun CUI Yan LI Bingzhen j.ANG sier DENG School of Mechatronics Engineering Henan University of Science and TechnologyLuoyang 471003China College of Ocean Engineering Guilin University of Electronic TechnologyBeihai 536000China

This paper explores an analytical model for Elastic Ring Squeeze Film Damper(ERSFD) with thin-walled ring and turbulent-j.t orifices, and uncovers its Oil Film Pressure Performance(OFPP). Firstly, the ring deformation is addressed by using the Fourier series expansion approach and the orifice outflow rate is characterized with the Prandtl boundary layer theory. Secondly, applying finite difference scheme, the influence of elastic ring flexibility, orifice diameter, and attitude angle on the OFPP is analyzed. Finally, Outer chamber pressure was measured experimentally at different rotor speeds. The results indicate that the outer chamber pressure coats an individual load-carrying region and spreads symmetrically pertaining to the attitude angle. Its amplitude drops as the elastic ring flexibility decreases but boosts with the reduction of the orifice *** inner chamber pressure, the orifice diameter effects a similar trend to the outer cavity, but exhibits more stable distribution regarding the attitude angle. Minimizing the elastic ring flexibility causes an increase in amplitude. The model is validated by the test results giving that the outer chamber pressure shifts synchronously and periodically with the variation of the attitude angle,while the pressure amplitude increases slightly at higher rotor speeds.

关键词： Elastic ring squeeze film damper Orifice flow Rolling bearing Thin-walled ring Turbulent j.t Vibration

Synthesis of Chitosan Quaternary Ammonium Salts

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Chinese Chemical Letters 2001年第12期12卷 1081-1084页

作者： Xu, WL Wu, j.Fu, cl Zhej.ang Univ Dept Chem Hua Jia Chi Sect Hangzhou 310029 Peoples R China

A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-soluble cationic chitosan quaternary ammonium salt. The products were characterized by IR, (HNMR)-H-1 and elemental analysis. The degree of substitution of chitosan quaternary ammonium salt was calculated by elemental analysis.

关键词： synthesis quaternization chitosan quaternary ammonium salts

The clinical rehabilitation of spine and spinal cord disorders: detection and evaluation using SPECT/CT

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Neural Regeneration Research 2014年第8期9卷 795-797页

作者： Max j. Scheyerer clément M.L.Werner Patrick Veit-Haibach Centre for Orthopaedic and Trauma Surgery University Medical CenterJosef-Stelzmann-Str.9CologneGermany Department of Surgery Division of TraumaSurgeryUniversity Hospital ZurichZurichSwitzerland Department of Medical Radiology Division of Nuclear MedicineUniversity Hospital ZurichZurichSwitzerland Department of Medical Radiology Diagnostic and Inverventional Radiolo-gyUniversity Hospital ZurichZurichSwitzerland

Spine-related disorders are caused by several factors including （1） spinal nerve/visceral nerve stimulation by perivertebral aseptic inflammation, （2） spinal nerve/visceral nerve compression by inj.red periverterbal soft tissue, dislocated perivertebral small j.int, and proliferative/degenerative tissue and, （3） secondary damage to the spinal cord, peripheral nerve, vessels and autonomic nerve, which further stimulate nerve root sheath and surround- ing pain-carrying nerve fibers. In many cases, the source of pain cannot be detected by standard image modalities. Particularly in anatomically complex regions like the spine, SPECT/CT can be helpful for some aspects by intro- ducing a metabolical dimension to the classical way of morphology-based diagnostic. The aim of the present review was to give an overview of the adoption of SPECT/CT in a clinical spine-focused setting.

关键词： SPECT The clinical rehabilitation of spine and spinal cord disorders detection and evaluation using SPECT/CT

Effect of humidity on the surface adhesion force of inorganic crystals by the force spectrum method

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Chinese Science Bulletin 2001年第11期46卷 912-914页

作者： Tang, j.Wang, C Liu, MZ Su, M Bai, cl Chinese Acad Sci Inst Chem Beijing 100080 Peoples R China

Effect of relative humidity on the surface adhesion force of several inorganic crystals of mica, CaF2 and KC1 was studied by atomic force microscopy (AFM). The results showed that the magnitude of surface adhesion force is mainly dependent on the surface free energy of the adsorbed liquid film, but almost independent of the thickness of the film. Furthermore, the deliquescence on the crystal surface was investigated, which demonstrated the capability of the force spectrum method to monitor changes in ionic concentrations of adsorbed liquid film in real-time.

关键词： mica CaF2 KC1 adhesion force relative humidity AFM.

Synthesis of single-walled carbon nanotubes by the vertical floating catalyst method

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Chinese Science Bulletin 2002年第2期47卷 158-161页

作者： Zhu, HW Li, XS Lij.e, C Xu, cl Liang, j.Wu, DH Tsing Hua Univ Dept Mech Engn State Key Lab Automot Safety & Energy Beijing 100084 Peoples R China

The vertical floating catalyst method is first used to produce single-walled carbon nanotubes (SWNTs) continuously on a large scale by a newly developed technique and pyrolysis of n-hexane. Diameter distributions, micro-structure and purity of the SWNTs film, rope and web are measured by Raman spectroscopy and electron microscope. The results show that SWNTs product has a high degree of orientation, a wide distribution of diameters (0.7-2.0 nm) and high purity of > 80 %.

关键词： single-walled carbon nanotubes (SWNT) vertical floating catalyst method Raman spectroscopy.

Effects of self-administered exercises based on Tuina techniques on musculoskeletal disorders of professional orchestra musicians: a randomized controlled trial

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j.urnal of Integrative Medicine 2015年第5期13卷 314-318页

作者： cláudia Maria Sousa Daniela Coimbra j.rge Machado Henry j.Greten Institute of Biomedical Sciences Abel Salazar University of Porto Porto Polytechnic Institute Superior School of Music and Performing Arts German Society of Traditional Chinese Medicine Heidelberg School of Chinese Medicine

BACKGROUND： Musicians are frequently affected by playing-related musculoskeletal disorders （PRMD）. Common solutions used by Western medicine to treat musculoskeletal pain include rehabilitation programs and drugs, but their results are sometimes disappointing. OBj.CTIVE： To study the effects of self-administered exercises based on Tuina techniques on the pain intensity caused by PRMD of professional orchestra musicians, using numeric visual scale （NVS）. DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS： We performed a prospective, controlled single-blinded, randomized study with musicians suffering from PRMD. Participating musicians were randomly distributed into the experimental （n = 39） and the control （n = 30） groups. After an individual diagnostic assessment, specific Tuina self-administered exercises were developed and taught to the participants. Musicians were instructed to repeat the exercises every day for 3 weeks. MAIN OUTCOME MEASURES： Pain intensity was measured by NVS before the intervention and after 1, 3, 5, 10, 15 and 20 d of treatment. The procedure was the same for the control group, however the Tuina exercises were executed in points away from the commonly-used acupuncture points. RESULTS： In the treatment group, but not the control group, pain intensity was significantly reduced on days 1, 3, 5, 10, 15 and 20. CONclUSION： The results obtained are consistent with the hypothesis that self-administered exercises based on Tuina techniques could help professional musicians controlling the pain caused by PRMD. Although our results are very promising, further studies are needed employing a larger sample size and double blinding designs.

关键词： Tuina musculoskeletal disorders professional orchestra musicians randomized controlled trial

Mechanisms of electrochemical magnesium(de)alloying of Mg-Sn and Mg-Pb polymorphs

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j.urnal of Magnesium and Alloys 2022年第6期10卷 1609-1616页

作者： clément Pechberty Antoine Klein Bernard Fraisse Lorenzo Stievano Romain Berthelot ICGM CNRSUniv.MontpellierENSCMMontpellierFrance RS2E CNRSHub de l’EnergieAmiensFrance

Different polymorphs of Mg-Sn and Mg-Pb intermetallic compounds were prepared by high-energy mechanical alloying and then investigated as active material in magnesium batteries. Beside thermodynamically stable Mg_(2)Sn and Mg_(2)Pb crystallizing in the anti-fluorite structure, other polymorphs Mg_(~2)Sn and Mg_(~2)Pb were prepared by increasing the ball-milling time. The first dealloying process is almost complete only for the cubic polymorphs, then similar capacities are observed during the subsequent alloying and dealloying *** to operando X-ray diffraction, the electrochemical mechanism is revealed and shows that the cubic polymorphs Mg_(2)Sn and Mg_(2)Pb tend to preferentially form during the alloying whatever the pristine intermetallic. Weak traces of Mg_(~2)Sn and Mg_(~2)Pb are observed during the alloying, suggesting that these polymorphs act as a by-product and/or an intermediate phases of the electrochemical process. Finally, the compatibility of cubic Mg_(2)Sn and Mg_(2)Pb with Mg(TFSI)_(2)-based electrolyte is confirmed in full cell vs. a positive electrode based on the Chevrel phase Mo6S8, although limited performance is achieved. This fundamental work provides new insights in the behavior of alloy-type negative electrodes for magnesium-ion batteries.

关键词： Magnesium batteries Alloy electrode Mechanochemistry Operando X-ray diffraction