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Reducing damage extent of epoxy coating on magnesium substrate by zr-enhanced PEO coating as an effective pretreatment

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Journal of magnesium and Alloys 2023年第2期11卷 641-656页

作者： z.Jamshidipour m.Toorani m.Aliofkhazraei m.mahdavian Department of materials Engineering Tarbiat Modares UniversityTehranIran Department of Surface Coatings and Corrosion Institute for Color Science and Technology(ICST)TehranIran

This research was undertaken to study the effect of zr-enhanced plasma electrolytic oxidation(PEO) as a pretreatment on the corrosion performance of epoxy coating applied on magnesium in 3.5 wt.% Na Cl solution. The parameters of delamination index along with coating damage index were extracted through electrochemical impedance spectroscopy(EIS) tests to determine how zr may affect the corrosion protection of duplex PEO/epoxy coated samples. Pull-off adhesion tests were also accomplished to form a better understanding of zr-enhanced PEO coating’ function. According to the obtained results, the presence of zr can reduce the damage to the coating system by almost twice.

关键词： magnesium EIS Pretreatment PEO Epoxy zirconyl nitrate

DNS in evolution of vorticity and sign relationship in wake transition of a circular cylinder:(pure)mode A

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Acta mechanica Sinica 2019年第6期35卷 1131-1149页

作者： L.m.Lin z.R.Tan Key Laboratory for mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Navigation Wuhan University of TechnologyWuhan 430063China Hubei Key Laboratory of Inland Shipping Technology Wuhan University of TechnologyWuhan 430063China

In the present paper,the spatio-temporal evolution of vorticity in the first wake instability,i.e.,(pure)mode A,is investigated in order to understand the wake vortex dynamics and sign relationships among vorticity *** numerical simulation(DNS)for the flow past a circular cylinder is performed,typically at a Reynolds number of 200,in the three-dimensional(3-D)wake *** to characteristics of time histories of fluid forces,three different stages are identified as the computational transition,the initial stage and fully developed *** the second initial stage,the original two-dimensional spanwise vortices become obviously three-dimensional associated with the streamwise or vertical vorticity intensified up to about *** a matter of fact,these additional vorticities,caused by the intrinsic 3-D instability,are already generated firstly on cylinder surfaces early in the computational transition,indicating that the three-dimensionality appeared early near the *** evolution of additional components of vorticity with features the same as mode A shows that(pure)mode A can be already formed in the late computational *** careful analysis of the vorticity field on the front surface,in the shear layers and near wake at typical times,two sign laws are *** illustrate intrinsic relationships among three vorticity components,irrelevant to the wavelength or Fourier mode and Reynolds number in(pure)mode *** importantly,the origin of streamwise vortices is found and explained by a new physical mechanism based on the theory of vortex-induced *** a result,the whole process of formation and shedding vortices with these vorticities is firstly and completely *** characteristics are presented in detail.

关键词： Wake transition Circular cylinder Vorticity mode A Sign law

Synthesis of an Anti-1,3-Diol Type Chiral Building Block

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Chinese Chemical Letters 1998年第11期9卷 987-988页

作者： wu, Y Guan, m W China Univ med Sci Sch Pharm Chengdu 610041 Peoples R China W China Univ med Sci Hosp 1 Chengdu 610041 Peoples R China

A chiral building block, anti-1,3-diol 2, has been synthesized in 7 steps, starting from readily available and inexpensive D-(+)-xylose.

关键词： chiral building block anti-1,3-Diol D(+)-xylose

Determination of volatile organic compounds in river water by solid phase extraction and gas chromatography

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Journal of Environmental Sciences 2004年第3期16卷 497-501页

作者： m.A.mottaleb m.z.Abedin m.S.Islam Department of Chemistry Department of Chemical Technology and Polymer SciencesDepartment of Chemical Technology and Polymer Sciences University of RajshahiRajshahi 6205 BangladeshDept.of Chemistry and BiochemistryBaylor UniversityWacoUSAShahjalal University of Science and TechnologySylhet 3114BangladeshShahjalal University of Science and TechnologySylhet 3114Bangladesh

A simple, rapid, and reproducible method is described employing solid phase extraction(SPE) using dichloromethane followed by gas chromatography(GC) with flame ionization detection(FID) for determination of volatile organic compound(VOC) from the Buriganga River water of Bangladesh. The method was applied to detect the benzene, toluene, ethylbenzene, xylene and cumene(BTEXC) in the sample collected from the surface or 15 cm depth of water. Two hundred ml of n hexane pretreated and filtered water samples were applied directly to a C 18 SPE column. BTEXC were extracted with dichloromethane and average concentrations were obtained as 0 104 to 0 372 μg/ml. The highest concentration of benzene was found as 0 372 μg/ml with a relative standard deviation(RSD) of 6 2%, and cumene was not detected. Factors influencing SPE e.g., adsorbent types, sample load volume, eluting solvent, headspace and temperatures, were investigated. A cartridge containing a C 18 adsorbent and using dichloromethane gave better performance for extraction of BTEXC from water. Average recoveries exceeding 90% could be achieved for cumene at 4℃ with a 2 7% RSD.

关键词： solid phase extraction river water environmental analysis VOC recoveries

Investigation on Fatigue model of Asphalt Concrete Containing Conductive Fillers

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武汉理工大学学报 2010年第17期32卷 62-66页

作者： LI W T wu S P zHU z H LIU z F Key Laboratory of Silicate materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

The snow and ice on asphalt pavement are very dangerous to people,automobiles and airplanes,so melting snow and ice becomes a high profile. Investigation on the asphalt concrete containing conductive fillers has a great contribution to the researches of melting snow and ice. However,it is few to research on the fatigue behavior which is important in the profile. By four-point bending fatigue tests,the specific fatigue models of conductive asphalt concrete were developed. The parameters of three fatigue models were regressed,the three models predicted the fatigue behavior by the strain levels,the strain levels and initial mix stiffness and dissipated energy respectively. In the model of the strain levels,the fatigue life is decreased at the same strain level as the conductive filler is added. The model based on the strain levels and initial mix stiffness reveals that the fatigue life is partly affected by the initial mix stiffness which is influenced by the conductive filler. The model used the dissipated energy approach is adopted to predict the fatigue behavior with the introduction of the impact the conductive filler on the dissipated energy.

关键词： conductive asphalt concrete model fatigue life strain level stiffness dissipated energy

Characterization for Fusion Candidate Vanadium Alloys

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Plasma Science and Technology 2004年第4期6卷 2395-2399页

作者： T.muroga T.Nagasaka J.m.Chen z.Y.Xu Q.Y.Huang Y.C.wu NationalInstituteforFusionScience Toki509-5292Japan SouthwesternInstituteofPhysics Chengdu610041China InstituteofPlasmaPhysics ChineseAcademyofSciencesHefei230031China

This paper summarizes recent achievements in the characterization ofcandidate vanadium alloys obtained for fusion in the framework of the Japan-China Core UniversityProgram. National Institute for Fusion Science (NIFS) has a program of fabricating high-purityV-4Cr-4Ti alloys. The resulting products (NIFS-HEAT-1,2), were characterized by various researchgroups in the world including Chinese partners. South Western Institute of Physics (SWIP) fabricateda new V-4Cr-4Ti alloy (SWIP-Heat), and carried out a comparative evaluation of hydrogenembrittlement of NIFS-HEATs and SWIP-Heat. The tensile test of hydrogen-doped alloys showed that theNIFS-HEAT maintained the ductility to relatively high hydrogen levels. The comparison of the datawith those of previous studies suggested that the reduced oxygen level in the NIFS-HEATs should beresponsible for the increased resistance to hydrogen embrittlement. Based on the chemical analysisdata of NIFS-HEATs and SWIP-Heats, neutron-induced activation was analyzed in Institute of PlasmaPhysics (IPP-CAS) as a function of cooling time after the use in the fusion first wall. The resultsshowed that the low level of Co dominates the activity up to 50 years followed by a domination of Nbor Nb and Al in the respective alloys. It was suggested that reduction of Co and Nb, both of whichare thought to have been introduced via cross-contamination into the alloys from the molds usedshould be crucial for reducing further the activation.

关键词： vanadium alloys characterization nuclear fusion

Steady vortex force theory and slender-wing flow diagnosis

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Acta mechanica Sinica 2007年第6期23卷 609-619页

作者： Y.T.Yang R.K.zhang Y.R.An J.z.wu State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing 100871China

The concept vortex force in aerodynamics is sys- tematically examined based on a new steady vortex-force theory （wu et al., Vorticity and vortex dynamics, Springer, 2006） which expresses the aerodynamic force （and moment） by the volume and boundary integrals of the Lamb vector. In this paper, the underlying physics of this theory is explored, including the general role of the Lamb vector in non- linear aerodynamics, its initial formation, and its relevance to the total-pressure non-uniformity. As a typical example, the theory is applied to the flow over a slender delta wing at a large angle of attack. The highly localized flow structures with high Lamb-vector peaks are identified in terms of their net contribution to various constituents of the total aerody-namic force. This vortex-force diagnosis sheds new light on the flow control and configuration optimization.

关键词： Vortex force - Delta-wing - Flow control

A model of Tangential Contact Damping Considering Asperity Interaction and Lateral Contact

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Acta mechanica Solida Sinica 2018年第6期31卷 758-774页

作者： W.P.Fu z.Q.Gao W.Wang J.B.wu School of mechanical and Precision Instrument Engineering Xi'an University of TechnologyXi'an 710048 China

A precise tangential contact damping model is proposed,which includes the lateral contact of the upper-lower asperities and the interaction of adjacent *** effects of the normal static preload,frequency,and amplitude of tangential displacement on the tangential contact damping were analyzed by simulation,***,the results of simulation are verified by *** tangential contact damping of considering the interaction and lateral contact of asperity is very close to the experimental results.

关键词： Asperity Lateral contact Interaction Tangential contact damping

Evaluating instrumented Charpy impact strain signals using curve fitting equations

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Journal of Central South University 2014年第2期21卷 600-609页

作者： m.B.Ali S.Abdullah m.z.Nuawi A.K.Ariffin z.m.Nopiah Department of mechanical and materials Engineering Faculty of Engineering and Built EnvironmentUniversiti Kebangsaan Malaysia Department of Structure and material Faculty of Mechanical EngineeringUniversiti Teknikal Malaysia Melaka

An effective and simple way to develop equations from impact strain signals was *** research has been performed in this area,but this equation is very important for evaluating input signals in finite element analysis impact tests and for obtaining additional information on material deformation and fracture processes under impact *** this purpose,dynamic impact responses were examined through signals obtained from a strain gauge installed on an impact striker connected to a data acquisition *** 6061-T6 was used to extract strain responses on the striker during Charpy impact *** analysis was performed using the I-kaz method,and curve fitting equations based on the equation for vibration response under a non-periodic force were used to evaluate the Charpy impact *** I-kaz coefficients and curve fitting equations were then compared and discussed with related parameters,such as velocities and *** and thickness were found to be related to the strain signal patterns,curve fitting equations and I-kaz *** equations developed using this method had R2 values greater than 97.7%.Finally,the constructed equations were determined to be suitable for evaluating Charpy impact strain signal patterns and obtaining additional information on fracture processes under impact loading.

关键词： charpy impact curve fitting I-kaz signal and strain