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Large nonlinear deflection behavior of IPMC actuators analyzed with an electromechanical model

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Acta Mechanica Sinica 2019年第5期35卷 992-1000页

作者： H.g.liu K.Bian K.Xiong Faculty of Civil Engineering and Mechanics Jiangsu UniversityZhenjiang 212013China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Mechanical and Electrical Engineering Guangzhou UniversityGuangzhou 510006China

This study presents an electromechanical engineering model for the analysis of the large deflection curves of ionic polymer-metal composite(IPMC)cantilever actuators under direct current(DC)*** this paper,the longitudinal normal strain performance of the material was investigated using digital image correlation on a *** deflection of the actuator is analytically obtained with the application of an elliptic integration method based on the relationship between strain gradient and excitation voltage,and the minimum excitation voltage is derived based on the assumption that the actuators have small *** validity of the electromechanical model is then justified with the experimental results obtained from Pt-and Ag-IPMC actuators at various excitation *** findings of this study confirm that the introduced electromechanical model can accurately describe the large nonlinear deflection behavior of IPMC actuators.

关键词： Actuator Ionic polymer metal composite Large deflection Electromechanical model

Characterization of face-centered cubic structure and deformation mechanisms in high energy shot peening process of TC17

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Journal of Materials Science & Technology 2022年第15期110卷 136-151页

作者： C.Yang M.Q.Li Y.g.liu School of Materials Science and Engineering Northwestern Polytechnical UniversityXi’an 710072China

The face-centered cubic structure(fcc)and its deformation behaviors,as well as the distinctive role of fcc-Ti in nanocrystallization in TC17 subjected to high energy shot peening(HESP),were investigated by using comprehensive high-resolution transmission electron microscopy(HRTEM).The results showed that there was a stress-induced fcc-Ti in TC17 with a lattice constant of 0.420–0.433 nm and the B-type orientation relationship between the hcp-Ti and the fcc-Ti as[2-1-10]_(hcp)//[-110]_(fcc)and(0001)_(hcp)//(111)_(fcc),which was accomplished by the gliding of Shockley partial dislocations with Burgers vector of 1/3[01-10]on the basal *** deformation twinning dominated the subsequent deformation of fcc-Ti,producing two types of{111}twins with different *** them,the I-type twin with complete structure was generated by successive gliding of Shockley partial dislocations with the same Burgers vector of 1/6[11-2].In contrast,the cooperative slip of three Shockley partials,whose sum of Burgers vectors was equal to zero,produced the II-type twin with zero net macroscopic *** then,the emission of Shockley partial with the Burgers vector of 1/6[11-2]on every three(111)fccplanes resulted in the formation of a 9R *** to the dissociation effect of lamellar fcc-Ti and the superior deformation ability of fcc structure,the occurrence of fcc-Ti effectively promoted surface nanocrystallization of TC17.

关键词： TC17 Severe plastic deformation Stress-induced phase transformation Deformation twinning Nanocrystallization

Chemical composition of gas from mantle xenoliths in alkali- basalt from Damaping, Hebei

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Chinese Science Bulletin 1997年第6期42卷 470-472页

作者： liu, g Wang, XB Li, LW State Key Laboratory of gas geochemistry Lanzhou Institute of Geology Chinese Academy of Sciences Lanzhou China

WE have measured the chemical composition of the gas extracted from ortho- and clino-pyroxenes in spinel lherzolite xenolith, and from black pyroxenolite xenolith in Cenozoic alkah-basalt from Damáping, Wanquan Count... 详细信息

关键词： mantle xenolith chemical composition of gas origin of H2

The cellular receptor for enterovirus 71

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Protein & Cell 2014年第9期5卷 655-657页

作者： Yue liu Michael g. Rossmann Department of Biological Sciences Purdue University West Lafayette IN 47907 USA

The Picornaviridae family consists of a large group of non- enveloped, icosahedral viruses with a single, positivestranded IRNA genome. The family includes pathogens that are notable for a variety of human and animal diseases （Racaniello, 2007）. Picornaviruses initiate infections by attachment to host cell receptor molecules and then undergo uncoating to release the viral genome into the cytosol for replication （Racaniello, 2007）. The enterovirus （EV） genus is perhaps the most intensively studied genus among the 26 known genera.

关键词： Picornaviridae genome Picornaviruses

A Low Frequency Vector Fast Multipole Algorithm with Vector Addition Theorem

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Communications in Computational Physics 2010年第10期8卷 1183-1207页

作者： Yang g.liu Weng Cho Chew Department of Electrical and Electronic Engineering The University of Hong KongPokfulam RoadHong Kong Department of Electrical and Electronic Engineering The University of Hong KongPokfulam RoadHong Kong.On Leave of Absence from the University of IllinoisUrbana-Champaign

In the low-frequency fast multipole algorithm(LF-FMA)[19,20],scalar addition theorem has been used to factorize the scalar green’s *** of this traditional factorization of the scalar green’s function by using scalar addition theorem,we adopt the vector addition theorem for the factorization of the dyadic green’s function to realize memory *** are to validate this factorization and use it to develop a low-frequency vector fast multipole algorithm(LF-VFMA)for lowfrequency *** the calculation of non-near neighbor interactions,the storage of translators in the method is larger than that in the LF-FMA with scalar addition *** it is independent of the number of ***,the storage of radiation and receiving patterns is linearly dependent on the number of *** it is worthwhile for large scale problems to reduce the storage of this *** this method,the storage of radiation and receiving patterns can be reduced by 25 percent compared with the LF-FMA.

关键词： LF-VFMA electromagnetics low frequency loop-tree basis memory saving surface integral equation vector addition theorem

STUDY OF RAY IRRADIATION ON DIAMOND-LIKE CARBON FILMS

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Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 26-32页

作者： g.A. liu T.M. Wang E.Q Dept. of Appl. Phy. Southwest Jiaotong Univ. Chengdu 610031 China

Diamond-like carbon (DLC) films have been deposited on glass substrates usingradio-frequency (rf) plasma deposition method. gamma -ray, ultraviolet (UV) ray were used toirradiate the DLC films. Raman spectroscopy and infrared (IR) spectroscopy were use to characterizethe changing characteristics of SP^3 C-H bond and hydrogen content in the films due to theirradiations. The results show that, the damage degrees induced by the UV ray on the SP^3 C-H bondsare much stronger than that by the gamma -ray. When the irradiation dose of gamma -ray reaches 1 OX10^4 gy, the SP^3 C-H bond reduces about 50 percent in number. The square electrical resistance ofthe films is reduced due to the irradiation of UV ray and this is caused by severe oxidation of thefilms. By using the results on optical gap of the films and the fully constrained network theory,the hydrogen content in the as-deposited films is estimated to be l0-25at. percent.

关键词： diamond-like carbon film gamma -ray irradiation ultraviolet rayirradiation SP^3 C-H bond infrared transmittance

Effects of Nb content in Ti–Ni–Nb brazing alloys on the microstructure and mechanical properties of Ti–22Al–25Nb alloy brazed joints

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Journal of Materials Science & Technology 2017年第7期33卷 682-689页

作者： Y.Wang X.Q.Cai Z.W.Yang D.P.Wang X.g.liu Y.C.liu Key Lab of Aclvanced Joining Technology School of Materials Science and Engineering Tianjin University Tiandin 300072 China

Vacuum brazing was successfully used to join Ti-22Al-25Nb alloy using Ti-Ni-Nb brazing alloys prepared by arc-melting. The influence of Nb content in the Ti-Ni-Nb brazing alloys on the interfacial microstructure and mechanical properties of the brazed joints was investigated. The results showed that the interfacial microstructure of brazed joint consisted of B2, O, ？3, and Ti2 Ni phase, while the width of brazing seams varied at different Nb contents. The room temperature shear strength reached359 MPa when the joints were brazed with eutectic Ti40Ni40Nb20 alloy at 1180？C for 20 min, and it was321, 308 and 256 MPa at 500, 650 and 800？C, respectively. Cracks primarily initiated and propagated in ？3compounds, and partially traversed B2＋O region. Moreover, the fracture surface displayed typical ductile dimples when cracks propagated through B2＋O region, which was favorable for the mechanical properties of the brazed joint.

关键词： Ti-22Al-25Nb alloy Ti-Ni-Nb brazing alloy Nb content Microstructure Mechanical properties

EFFECT OF NANOCRYSTALLINE AND TWIN BOUNDARIES ON CORROSION BEHAVIOR OF 316L STAINLESS STEEL USINg SMAT

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Acta Metallurgica Sinica(English Letters) 2006年第3期19卷 183-189页

作者： A.Q. Lü Y. Zhang Y. Li g. liu Q.H. Zang C.M. liu School of Materials and Metallurgy Northeastern University Shenyang 110004 China Jiuquan Iron ＆ Steel （group） go. Ltd Jiayuguan 735100 China State Key Laboratory for Corrosion and Protection of Metals Institute of Metal Research The Chinese Academy of Sciences Shenyang 110015 China Shenyang National Laboratory for Materials Science Institute of Metal Research The Chinese Academy of Science Shenyang 110016 China

By means of surface mechanical attrition treatment （ SMAT）, the groin size with a diameter of aboat 60hm formed at about 20μm depth and numerous mechanical twins at about 50μm depth from the treated surface were synthesized in 316L stainless steel because of the different distributions of strain and strain rate along depth orientation. For instance the maximum strain rate reached 10^3-10^4s^-1 on the top surface. The relationship between the microsturcture and the corrosion property was studied in 0.05M H2SO4＋ 0.25M Na2SO4 aqueous solution, and the results show an extreme improvement of corrosion resistance owing to the appearance of twin boundaries and the obvious reduction in corrosion resistance attributed to the presence of nanocrystaline boundaries.

关键词： surface mechanical attrition treatment 316L stainless steel corrosion property twin boundary nanocrystaline boundary

Effect of Mo Addition on Microstructural Characteristics in a Re-containing Single Crystal Superalloy

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Journal of Materials Science & Technology 2015年第2期31卷 143-147页

作者： X.g.liu L.Wang L.H.Lou J.Zhang Superalloys Division Institute of Metal ResearchChinese Academy of Sciences Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

The effect of Mo addition on microstructural characteristics of a nickel-base single crystal superalloy containing 4 wt% Re was investigated. The γ/γ’ partitioning ratios determined by energy dispersive spectrometer attached to a transmission electron microscope showed that the addition of Mo enhanced the partitioning of Re,W and Cr in the g matrix while decreased the concentration of Ta in the matrix. Synchrotron radiation diffraction was adopted to measure the γ/γ’ lattice misfit at room temperature. The results indicated that Mo addition changed the γ/γ’ lattice misfit towards larger negative as well as increased the tetragonal distortion of the γ lattice. Additionally,Mo addition led to microstructural instability and altered the precipitation behavior of topologically close-packed phases during 1100 C exposure. Instead of precipitating directly from the matrix,the μ phase was observed to be converted from the α phase which precipitated preferentially as a metastable intermediate in the alloy with high Mo content.

关键词： Superalloy Molybdenum Microstructure Partitioning