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Nonlinear Transient Response of Functionally Graded Material Sandwich Doubly Curved Shallow Shell Using New Displacement Field

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Acta Mechanica Solida Sinica 2018年第1期31卷 108-126页

作者： Z.N.Li Y.X.hao W.Zhang j.h.Zhang College of Mechanical Engineering Beijing Information Science and Technology University College of Mechanical Engineering Beijing University of Technology

In this paper, the nonlinear transient dynamic response of functionally graded material （FGM） sandwich doubly curved shell with homogenous isotropic material core and functionally graded face sheet is analyzed using a new displacement field on the basis of Reddy＇s third-order shear theory for the first time. The equivalent material properties for the FGM face sheet are assumed to obey the rule of simple power law function in the thickness direction. Based on Reddy＇s theory of higher shear deformation, a new displacement field is developed by introducing the secant function into transverse displacement. Four coupled nonlinear differential equations are obtained by applying hamilton＇s principle and Galerkin method. It is assumed that the FGM sandwich doubly curved shell is subjected to step loading, air-blast loading, triangular loading, and sinusoidal loading, respectively. On the basis of double-precision variable- coefficient ordinary differential equation solver, a new program code in FORTRAN software is developed to solve the nonlinear transient dynamics of the system. The influences of core thickness, volume fraction, core-to-face sheet thickness ratio, width-to-thickness ratio and blast type on the transient response of the shell are discussed in detail through numerical simulation.

关键词： New displacement fields Functionally graded materials Sandwich doubly curvedshell Blast load Nonlinear transient response

Impedance spectroscopy study on Mn_(1+x)Fe_(2-2x)Ti_xO_4(0≤x≤0.5) ferrites

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journal of Central South University 2010年第6期17卷 1133-1138页

作者： KUMAR S BATOO K M PRAKASh R ChOI h K KOO B h SONG j I ChUNG h jEONG h lee C G School of Nano and Advanced Materials Engineering Changwon National UniversityChangwon 641773Korea King Abdullah Institute for Nanotechnology King Saud UniversityRiyadh 11451Saudi Arabia Department of Mechanical Engineering Changwon National UniversityChangwon 641773Korea Department of Precision & Mechanical Engineering and BK21 Eco-Friendly heat & Cold Energy Mechanical Research Team Gyeongsang National U niversityTongyeong 650160Korea

The complex impedance spectroscopy and surface morphology of Mn1+xFe2-2xTixO4(0≤x≤0.5) system,prepared using a conventional solid state reaction technique,were *** impedance spectroscopy measurements were carried out at room temperature in the frequency range of 42-5 *** electrical processes in the samples were modeled in the form of an equivalent circuit made up of a combination of two parallel RC circuits attributed to grain and grain *** DC conductivity obtained by extrapolation of AC data using impedance spectroscopy and four-probe method increases at 10% doping of Ti *** energy-dispersive X-ray(EDX) pattern confirmed the homogeneous mixing of the Mn,Fe,Ti and O atoms in pure and doped ferrite samples.

关键词： spinel ferrite magnetic properties impedance spectroscopy Ti4+ ions doping

An Interface-Capturing Method for Resolving Compressible Two-Fluid Flows with General Equation of State

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Communications in Computational Physics 2009年第10期6卷 1137-1162页

作者： T.S.lee j.G.Zheng S.h.Winoto Department of Mechanical Engineering National University of SingaporeSingapore 119260

In this study,a stable and robust interface-capturing method is developed to resolve inviscid,compressible two-fluid flows with general equation of state(EOS).The governing equations consist of mass conservation equation for each fluid,momentum and energy equations for mixture and an advection equation for volume fraction of one fluid *** of pressure equilibrium across an interface is used to close the model ***-hancock scheme is extended to construct input states for Riemann problems,whose solutions are calculated using generalized hLLC approximate Riemann *** mesh refinement(AMR)capability is built into hydrodynamic *** resulting method has some ***,it is very stable and robust,as the advection equation is handled ***,general equation of state can model more materials than simple EOSs such as ideal and stiffened gas EOSs for *** addition,AMR enables us to properly resolve flow features at disparate ***,this method is quite simple,time-efficient and easy to implement.

关键词： MUSCL-hancock scheme adaptive mesh refinement compressible two-fluid flows general equation of state

A functional tacrolimus-releasing nerve wrap for enhancing nerve regeneration following surgical nerve repair

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Neural Regeneration Research 2025年第1期20卷 291-304页

作者： Simeon C.Daeschler Katelyn j.W.So Konstantin Feinberg Marina Manoraj jenny Cheung jennifer Zhang Kaveh Mirmoeini jPaul Santerre Tessa Gordon Gregory hBorschel SickKids Research Institute Neuroscience and Mental Health ProgramTorontoONCanada Institute of Biomaterials and Biomedical Engineering University of TorontoTorontoONCanada Indiana University School of Medicine IndianapolisINUSA Division of Plastic and Reconstructive Surgery the Hospital for Sick ChildrenTorontoONCanada Translational Biology and Engineering Program Ted Rogers Centre for Heart ResearchInstitute of Biomedical EngineeringFaculty of DentistryUniversity of TorontoTorontoONCanada

Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong ***,there are no FDA-approved therapies available to promote nerve *** accelerates axonal regeneration,but systemic side effects presently outweigh its potential benefits for peripheral nerve *** authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site,with suitable properties for scalable production and clinical application,aiming to promote nerve regeneration and functional recovery with minimal systemic drug *** is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 *** and drug loading are adjustable for applications in small and large caliber nerves,and the wrap degrades within 120 days into biocompatible *** released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80%compared with systemic *** its surgical suitability and preclinical efficacy and safety,this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.

关键词： biodegradable local drug delivery nerve injury nerve regeneration nerve wrap tacrolimus

Trends in characteristics of neurologists who provide stroke consultations in the USA,2008-2021

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Stroke & Vascular Neurology 2023年第1期8卷 86-88页

作者： Carter h Nakamoto Andrew D Wilcock lee h Schwamm jennifer j Majersik Kori S Zachrison Ateev Mehrotra Department of health Care Policy Harvard Medical SchoolBostonMassachusettsUSA Department of Family Medicine University of Vermont Larner College of MedicineBurlingtonVermontUSA Department of Neurology Massachusetts General HospitalBostonMassachusettsUSA Department of Neurology University of UtahSalt Lake CityUtahUSA Department of Emergency Medicine Massachusetts General HospitalBostonMassachusettsUSA Division of General Medicine and Primary Care Beth Israel Deaconess Medical CenterBostonMassachusettsUSA

Introduction Patients with acute ischaemic strokes(AIS),on average,fare better with timely neurologist consultation,and a growing proportion of them receive ***,little is known about trends in the characteristics of neurologists who treat *** We identified AIS and transient ischaemic attack(TIA)episodes with neurologist consults in fee-for service Medicare from january 2008 to September *** each episode,we determined whether the neurologist was a vascular neurologist,was a high-volume provider,whether the patient was transferred between hospitals and the distance between the patient’s home and physician’s *** From 2008 to 2021,the share of AIS/TIA episodes(n=5073294)with neurologist consults increased(52.9%to 61.7%).Among episodes with consults,the fraction conducted by a vascular neurologist(5.2%to 13.7%)or by a high-volume neurologist(13.2%to 14.9%)also *** fraction with the patient’s home and neurologist greater than 100 miles apart(4.8%to 9.6%)or in different states(5.1%to 8.1%)increased,as did the fraction with transfers(4.2%to 8.5%).Discussion Over the study period,the proportion of AIS/TIA episodes with consultations from neurologists with either vascular neurology certifications or high volumes increased substantially.

关键词： acute characteristics consultation

Mechanisms of high Coercivity in Ni/NiO Composite Films by Post Annealing

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材料科学与工程学报 2007年第6期25卷 858-860页

作者： j.B. Yi j. Ding Mansoor Bin Abdul jalil B.h. Liu S. Thongmee j.h. Yin Z.L. Zhao Department of Materials Science and Engineering National University of Singapore 119260 Singapore Department of Electrical ＆ Computer Engineering National University of Singapore 119260 Singapore

A coercivity as large as 2.4 kOe has been achieved in the Ni/NiO composite film after an annealing under a magnetic field of 10 kOe and an O_2 partial pressure of 0.001 *** coercivity was attributed to the strong exchange coupling of Ni and *** grain size of Ni and NiO was observed after the *** enhanced coercivity is probably associated with the domain wall pinning by local energy minima,the distribution of Ni and NiO,and the domain structure in the interface of Ni/NiO generated under the presence of the magnetic field during the post-annealing.

关键词：矫顽性镍氧化镍复合薄膜焊后退火交换耦合

Evaluation of the virulence of entomopathogenic fungus, Isaria fumosorosea isolates against subterranean termites Coptotermes spp.(Isoptera:Rhinotermitidae)

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journal of Forestry Research 2019年第1期30卷 213-218页

作者： j.j.jessica T.L.Peng A.S.Sajap S.h.lee S.A.Syazwan Department of Forest Management Faculty of ForestryUniversiti Putra Malaysia (UPM) Faculty of Veterinary Medicine University Malaysia Kelantan Institute of Tropical Forestry and Forest Products Universiti Putra Malaysia (UPM) Mycology and Pathology Laboratory Forest Biodiversity Division Forest Research Institute Malaysia

The entomopathogenic fungus Isaria fumosorosea Wize, formerly known as Paecilomyces fumosoroseus is reported as a promising biocontrol agent for controlling subterranean termites, particularly those belonging to the family Rhinotermitidae. In Malaysia, the family Rhinotermitidae includes two species of subterranean termites with extremely high economic importance; namely Coptotermes curvignathus holmgren, and the Asian SLubterranean Termite (Coptotermes gestroi Wasmann). To comprehend the potential control of this soil-dwelling fungus against these subterranean termites in Malaysia, an investigation was carried out by testing the pathogenecity of 11 isolates against these termite species. All isolates showed pathogenic potential against the termite (Mortality rate of C. curvignathus:84.4%; C. gestroi:67.3%). IsolatePF49 was the most effective against both species of termites and was further tested for its virulence and *** LC_(50) values of PF49 against C. curvignathus and *** were 7.55×103 and 1.09×102 conidia/ml,respectively. The average number of days required to complete the mycosis process in C. curvignathus and *** were 4.7 and 8 days, respectively. These fungi are believed useful for protecting living trees, plants, wood,wood structures, and other cellulosic materials susceptible to termite infestation and damage.

关键词： Biological control Entomopathogenic fungus Subterranean termites Lethal concentration

Numerical Simulation of Duct Flow with Fog Droplets

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journal of Thermal Science 2010年第6期19卷 533-539页

作者： Abhilash Suryan j. K. lee D. S. Kim h. D. Kim Department of Mechanical Engineering Andong National University FMTRC Daejoo Machinery Co.

Evaporative cooling is a widely used air cooling technique. In this method, evaporation of a liquid in the surrounding air cools the air in contact with it. In the current investigation, numerical simulations are carded out to visualize the evaporation and dynamics of tiny water droplets of different diameters in a long air duct. The effect of initial droplet size on the temperature and relative humidity distribution of the air stream in the duct is investigated. Three different initial conditions of air are considered to verify the influence of ambient conditions. Droplet spray patterns are also analyzed to identify the suitable locations for the spray nozzles within the duct. The resuits obtained are displayed in a series of plots to provide a clear understanding of the evaporative cooling process as well as the droplet dynamics within the ducts.

关键词： Evaporative cooling Fog droplet Two-phase flow Relative humidity

A comparison study of Ce/La and Ca microalloying on the bio-corrosion behaviors of extruded Mg-Zn alloys

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journal of Magnesium and Alloys 2020年第4期8卷 1269-1280页

作者： j.h.Chu L.B.Tong Z.h.jiang D.N.Zou Q.j.Wang S.F.Liu h.j.Zhang School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi'an 710055China State Key Laboratory of Rare Earth Resources Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Key Lab of Automobile Materials College of Materials Science and EngineeringJilin UniversityNanling CampusChangchun 130025China

The influences of Ca and Ce/La microalloying on the microstructure evolution and bio-corrosion resistances of extruded Mg-Zn alloys have been systematically investigated in the current *** with single Ca or Ce/La addition,the Ca-Ce/La cooperative microalloying results in an outstanding grain refinement,because the fine secondary phase particles effectively hinder the recrystallized grain *** coarse Ca2Mg6Zn3 phases promote the formation of Ca3(PO4)2 or hydroxyapatite particles during the immersion process and accelerate the dissolution of the corrosion product film,which destroys its integrity and results in the deterioration of anti-corrosive *** Ce/La elements can be dispersed within the conventional Mg7Zn3 phases,which reduce the internal galvanic corrosion between Mg matrix and the secondary phases,leading to an obvious improvement of corrosion ***,the Ca-Ce/La cooperative microalloying achieves a homogenous fine-grained microstructure and improves the protective ability of surface film,which will pave a new avenue for the design of biomedical Mg alloys in the coming future.

关键词： Extruded Mg-Zn alloy Ca and Ce/La microalloying Microstructure evolution Bio-corrosion behaviors