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Surface characteristics,corrosion behavior,and antibacterial property of Ag-implanted NiTi alloy

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Rare Metals 2013年第2期32卷 113-121页

作者： Peng Luo sheng-nan Wang Ting-Ting Zhao Yan Li School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology Beijing University of Aeronautics and Astronautics

NiTi shape memory alloy was modified by Ag ion implantation with different incident doses to improve its antibacterial property. The atomic force microscopy, auger electron spectroscopy, and X-ray photoelectron spectroscopy show that the surface of NiTi alloy is covered by TiO2 nano-film with embedded pure Ag with a peak concentration of 5.0 at% at the incident dose of 1.5 x10^17 ***-a, and Ni concentration is reduced in the super- ficial surface layer. The surface roughness reaches the maximum value nearly twice higher than the control sample at the incident dose of 1.5x10^17 ***-2. The potentiodynamic anodic polarization curves show that the Ag-implanted NiTi samples possess higher self-corrosion potential （Ecorr） and lower self-corrosion current density （icor0 but lower breakdown potential （Ebr）. Therefore, the corrosion resistance of the Ag-NiTi is comparable to, if not better than, the untreated NiTi. The antibacterial tests reveal that there is a distinct reduction of the germ numbers on the Ag-NiTi, which is due to the direct contact between Ag and germ, and enhanced by the leaching Ag ions.

关键词： NiTi Ag Ion implantation Corrosionresistance Antibacterial property

TURBULENT OPEN CHANNEL FLOW SUBJECTED TO THE CONTROL OF A SPANWISE TRAVELING WAVE

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Journal of Hydrodynamics 2009年第1期21卷 65-70页

作者： LIU nan-sheng WANG Lei LU Xi-yun Department of Modem Mechanics University of Science and Technology of China Hefei 230026 China

Turbulent open channel flows subjected to the control of a spanwise traveling wave have been investigated by means of Direct Numerical Simulation （DNS）. The objective of this study is to reveal the response of the near-wall and surface-influenced turbulence to the spanwise traveling wave control. Three typical frequencies of the spanwise traveling wave, i.e., high-, middle- and low-frequency, corresponding to the exciting periods at 25, 50 and 100, are considered to study the turbulence dynamics in the wall and surface regions. To elucidate the behaviors of turbulence statistics, some typical quantities, including the mean velocity, velocity fluctuations and the structures of turbulence fluctuations, are exhibited and analyzed.

关键词： turbulent open channel flow traveling wave Direct Numerical Simulation (DNS) turbulence statistics turbulence structures

Asymmetric self-diffusion with orientation-dependence of water molecule in finite timescale

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Science China(Physics,Mechanics & Astronomy) 2016年第7期59卷 20-24页

作者： Xu Wei nan sheng RongZheng Wan GuoHui Hu HaiPing Fang Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology Shanghai Institute of Applied PhysicsChinese Academy of Sciences

Self-diffusion of water has been investigated by molecular dynamics simulations. It was found that the preference of the direction in self-diffusion of water is orientation dependent in a finite time. For a time of-lO0 ps, there are more possibilities for water molecules moving along the initial dipole orientation than in the opposite direction. This reveals that self-diffusion of water molecules is asymmetric in a finite time. We tested four water models and found that they all show similar asymmetric diffusion, indicating that asymmetric diffusion of water is intrinsic behavior rather than induced by the water model. These results are important for understanding and application of asymmetric diffusion in research fields such as biological water and confined water in small dimensions.

关键词： water diffusion dipole orientation asymmetry

Doping effect on thermoelectric properties of nonstoichiometric AgSbTe_2 compounds

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International Journal of Minerals,Metallurgy and Materials 2011年第3期18卷 352-356页

作者： sheng-nan Zhang Guang-yu Jiang Tie-jun Zhu Xin-bing Zhao sheng-hui Yang State Key Laboratory of Silicon Materials Department of Materials Science and Engineering Zhejiang University Hangzhou 310027 China Northwest Institute of Non-Ferrous Metal Research Xi＇an 710016 China

Nonstoichiometric ternary thermoelectric materials Ag0.84Sb1.15M0.01Te2.16 （M=Ce, Yb, Cu） were prepared by a direct melt-quench and hot press process. The carrier concentration of all the samples increased after doping. Thermoelectric properties, namely electrical con-ductivity, Seebeck coefficient, and thermal conductivity, were measured from 300 to 673 K. The phase transition occurring at about 418 K representing the phase transition from b-Ag2Te to a-Ag2Te influenced the electrical transport properties. The electrical conductivities of Ce and Yb doped samples increased after doping from 1.9×104 to 2.5×104 and 2.3×104 S·m-1, respectively, at 673 K. Also, at room temperature, the Seebeck coefficient of the Ce doped sample relatively increased corresponding to the high carrier concentration due to the changes in the band structure. However, all the thermal conductivities increased after doping at low temperature. Because of the higher thermal conductivity, the dimensionless figure of merit ZT of these doped samples has not been improved.

关键词： thermoelectric materials rare earth elements doping silver antimony telluride

Parametric Vibration Analysis of Submerged Floating Tunnel Tension Legs

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China Ocean Engineering 2020年第1期34卷 131-136页

作者： SUN sheng-nan SU Zhi-bin FENG Yun-fen XU Xian-yi School of Architecture and Civil Engineering Liaocheng University

According to the characteristics of submerged floating tunnel anchored by tension legs,simplifying the tube as point mass and assuming that the tension leg is a nonlinear beam model hinged at both ends,the nonlinear vibration equation of the tension leg is *** equation is solved by the Galerkin method and Runge Kutta ***,numerical analysis of typical submerged floating tunnel tension leg is carried *** is shown that,the parametric vibration response of the submerged floating tunnel tension leg is related to the amplitude and frequency of the end *** considering axial resonance and transverse resonance,it is reasonable that higher order modes are abandoned and only the first three modes are *** axial resonance amplitude of the second or third order mode is equivalent to the first order mode axial resonance amplitude,which should not be ignored.

关键词： submerged floating tunnel tension leg parametric vibration numerical analysis

Source Apportionment of Ambient PM_(10) in the Urban Area of Longyan City,China:a Comparative Study Based on Chemical Mass Balance Model and Factor Analysis Method

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Chemical Research in Chinese Universities 2012年第2期28卷 204-208页

作者： QIU Li-min LIU Miao WANG Ju ZHANG sheng-nan FANG Chun-sheng Environmental Science Department College of Environment and ResourcesJilin UniversityChangchun 130012P.R.China Key Laboratory of Groundwater Resources and Environment Ministry of EducationJilin UniversityChangchun 130021P.R.China

In order to identify the day and night pollution sources of PM10 in ambient air in Longyan City,the authors analyzed the elemental composition of respirable particulate matters in the day and night ambient air samples and various pollution sources which were collected in January 2010 in Longyan with inductivity coupled plasma-mass spectrometry（ICP-MS）.Then chemical mass balance（CMB） model and factor analysis（FA） method were applied to comparatively study the inorganic components in the sources and receptor *** results of factor analysis show that the major sources were road dust,waste incineration and mixed sources which contained automobile exhaust,soil dust/secondary dust and coal dust during the daytime in Longyan City,*** are two major sources of pollution which are soil dust and mixture sources of automobile exhaust and secondary dust during the night in *** results of CMB show that the major sources are secondary dust,automobile exhaust and road dust during the daytime in *** major sources are secondary dust,soil dust and automobile exhaust during the night in *** results of the two methods are similar to each other and the results will guide us to plan to control the PM10 pollution sources in Longyan.

关键词： Factor analysis(FA) method Chemical mass balance(CMB) model Source apportionment Atmospheric particle PM10

Effect of thermal oxidation on the surface characteristics and corrosion behavior of a Ta-implanted Ti-50.6Ni shape memory alloy

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International Journal of Minerals,Metallurgy and Materials 2012年第12期19卷 1134-1141页

作者： sheng-nan Wang Yan Li Ting-ting Zhao School of Materials Science and Engineering Beihang University Beijhag 100191 China Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology Beihang University Beijing 100191 China Key Laboratory of Aerospace Materials and Performance (Ministry of Education) Beihang University Beijing 100191 China

A NiTi shape memory alloy （SMA） modified by Ta ion implantation was subjected to oxidation treatment in air at 723 and 873 K. Atomic force microscopy （AFM）, Auger electron spectroscopy （AES）, and grazing incidence X-ray diffraction （GIXRD） measurements were conducted to investigate the surface characteristics, including surface topography, elemental depth profiles, and surface phase structures. The surface roughness of the Ta-implanted NiTi increases after oxidation, and the higher the oxidation temperature is, the larger the value is. The surface of the Ta-implanted NiTi oxidized at 723 K is a nanolayer mainly composed of TiO2/Ta2O5 and TiO with depressed Ni content. The Ta-implanted NiTi oxidized at 873 K is mainly covered by rutile TiO2 in several micrometers of thickness. Potentiodynamic polarization tests indicated that the corrosion resistance of the Ta-implanted NiTi was improved after thermal oxidation at 723 K, but a negative impact was found for the Ta-implanted NiTi oxidized at 873 K.

关键词： nickel alloys titanium alloys shape memory effect ion implantation oxidation corrosion resistance

Asymmetrical free diffusion with orientation-dependence of molecules in finite timescales

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Science China(Physics,Mechanics & Astronomy) 2013年第6期56卷 1047-1052页

作者： sheng nan TU YuSong GUO Pan WAN RongZheng FANG HaiPing Division of Interfacial Water Shanghai Institute of Applied Physics Chinese Academy of Sciences Institute of Systems Biology Shanghai University

Using molecular dynamics simulations, we show that free diffusion of a nanoscale particle (molecule) with asymmetric structure critically depends on the orientation in a finite timescale of picoseconds to nanoseconds. In a timescale of ~100 ps, there are ~10% more possibilities for the particle moving along the initial orientation than moving opposite to the orientation; and the diffusion distances of the particle reach ~1 nm. We find that the key to this observation is the orientation-dependence of the damping force to the moving of the nanoscale particle and a finite time is required to regulate the particle orientation. This finding extends the work of Einstein to nano-world beyond random Brownian motion, thus will have a critical role in the understanding of the nanoscale world.

关键词： orientation diffusion finite timescales

Late SV40 factor:A key mediator of Notch signaling in human hepatocarcinogenesis

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World Journal of Gastroenterology 2011年第29期17卷 3420-3430页

作者： Ren-Hua Fan Jing Li nan Wu Ping-sheng Chen Department of Pathology School of MedicineSoutheast UniversityNanjing 210009Jiangsu ProvinceChina

AIM:To investigate the relationship between late SV40 factor(LSF)and Notch signaling in the development and progress of hepatocellular carcinoma(HCC).METHODS:Liver cancer tissue specimens from 25 patients were analyzed for Notch-1 and LSF expression by *** correlation between expression and the biological effects of Notch-1 and LSF were analyzed using genetic and pharmacological strategies in HCC cell lines and human normal cell lines,including hepatic stellate cells(HSC)and human embryonic kidney epithelial cells(HEK).RESULTS:Immunohistochemistry showed that both Notch-1 and LSF were significantly upregulated in HCC samples(76%,19/25,P<0.0001 and 84%,21/25,P<0.0001,respectively)compared with non-cancer *** of Notch-1 by exogenous transfection of Notch1 intracellular domain increased LSF expression in HSC and HEK cells to levels similar to those seen in HepG2 ***,blocking Notch-1 activation with aγ-secretase inhibitor,DAPT,downregulated LSF expression in HepG2 ***,a biological behavior assay showed that forced overexpression of LSF promoted HepG2 cell proliferation and ***:LSF is a key mediator of the Notch signaling pathway,suggesting that it might be a novel therapeutic target for the treatment of HCC.

关键词： Notch receptor Late SV40 factor Signal transduction Hepatocellular carcinoma