检索结果-南通市图书馆

Fabrication and characterization of Undoped and Cobalt-doped ZnO Based UV Photodetector Prepared by RF-sputtering

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2013年第12期29卷 1139-1145页

作者： Husam S.Al-Salman m.J.Abdullah School of Physics University Sains Malaysia Department of Physics College of ScienceUniversity of Basrah

Undoped and 1 at.% Co-doped ZnO nanostructure based UV photodetectors were successfully fabricated by RF- magnetron sputtering technique with comb like Pt electrodes. Cobalt ions were successfully incorporated into the lattice of the ZnO nanostructure without changing its wurtzite structure. It was indicated that Co-doping can effectively adjust the luminescence properties of the ZnO nanostructure. The undoped and Co-doped ZnO photodetectors were observed to have photosensitivities of 1.44 x 104 % and 8.57 x 102 % and low dark currents of 9.74 x 10-8 A and 1.18 x 10-7 A, respectively.

关键词： characterization Co-doped ZnO UV photodetector

Static and dynamic responses of a microcantilever with a T-shaped tip mass to an electrostatic actuation

在线全文

学校读者我要写书评

暂无评论

Acta mechanica Sinica 2016年第6期32卷 1104-1122页

作者： B.Firouzi m.Zamanian S.A.A.Hosseini Department of mechanical Engineering Faculty of Engineering Kharazmi University

In this study, nonlinear static and dynamic responses of a microcantilever with a T-shaped tip mass excited by electrostatic actuations are investigated. The electrostatic force is generated by applying an electric voltage between the horizontal part of T-shaped tip mass and an opposite electrode plate. The cantilever microbeam is modeled as an Euler-Bernoulli beam. The T-shaped tip mass is assumed to be a rigid body and the nonlinear effect of electrostatic force is considered. An equation of motion and its associated boundary conditions are derived by the aid of combining the Hamilton principle and Newton’s method. An exact solution is obtained for static deflection and mode shape of vibration around the static position. The differential equation of nonlinear vibration around the static position is discretized using the Galerkin method. The system mode shapes are used as its related comparison functions. The discretized equations are solved by the perturbation theory in the neighborhood of primary and subharmonic resonances. In addition, effects of mass inertia, mass moment of inertia as well as rotation of the T-shaped mass, which were ignored in previous works, are considered in the analysis. It is shown that by increasing the length of the horizontal part of the T-shaped mass, the amount of static deflection increases, natural frequency decreases and nonlinear shift of the resonance frequency increases. It is concluded that attaching an electrode plate with a T-shaped configuration to the end of the cantilever microbeam results in a configuration with larger pull-in voltage and smaller nonlinear shift of the resonance frequency compared to the configuration in which the electrode plate is directly attached to it.

关键词： mEmS Electrostatic Static deflection Natural frequency Pull-in voltage Perturbation theory T-shaped mass Primary and subharmonic resonances

Fabrication of chitosan/silica hybrid coating on AZ31 mg alloy for orthopaedic applications

在线全文

学校读者我要写书评

暂无评论

Journal of magnesium and Alloys 2023年第2期11卷 614-628页

作者： m.Kalaiyarasan S.Pugalmani N.Rajendran Department of Chemistry CEG CampusAnna UniversityChennai600025Tamil NaduIndia Department of Orthodontics Saveetha Dental College and HospitalsSaveetha Institute of Medical and Technical ScienceSaveetha UniversityChennai-600077India

Biocompatible conversion of chitosan and chitosan/silica hybrid coating were prepared to enhance the biocompatibility and corrosion resistance of biodegradable AZ31 mg alloy. The coatings were optimized and analysed with potentiodynamic polarization, SEm, ATR-IR and XPS studies. Potentiodynamic polarization studies, revealed that the coatings exhibited high corrosion resistance. The surface morphology of the Ch-3/Si coating showed small globular rough structure. The presence of functional groups was confirmed by ATR-IR. For a better understanding of chitosan/silica hybrid coating, the chemical states were examined by XPS studies. The in-vitro bioactivity of the coated samples was evaluated in Earle’s solution, which formed a dense layer of coral-like structure and calcium-deficient apatite with less stoichiometric ratio than the hydroxyapatite. In-vitro cell culture studies exhibited a good cell proliferation rate and the fabricated Ch-3/Si coating was found to be non-hemolytic. The bacterial studies proved that Ch-3/Si coating possessed inherent antibacterial activity.

关键词： AZ31 mg alloy Chitosan/silica Hemocompatibility mTT assay and antibacterial Studies

Simulation of buoyancy-induced turbulent flow from a hot horizontal jet

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2014年第1期26卷 104-113页

作者： El-AmIN m.F. SUN Shuyu SALAm Amgad Computational Transport Phenomena Laboratory (CTPL) Division of Physical Sciences and EngineeringKing Abdullah University of Science and Technology

Experimental visualizations and numerical simulations of a horizontal hot water jet entering cold water into a rectangular storage tank are described. Three different temperature differences and their corresponding Reynolds numbers are considered. Both experimental visualization and numerical computations are carried out for the same flow and thermal conditions. The realizable k-e model is used for modeling the turbulent flow while the buoyancy is modeled using the Boussinesq approximation. Polynomial approximations of the water properties are used to compare with the Boussinesq approximation. Numerical solutions are obtained for unsteady flow while pressure, velocity, temperature and turbulence distributions inside the water tank as well as the Froude number are analyzed. The experimental visualizations are performed at intervals of five seconds for all different cases. The simulated results are compared with the visualized results, and both of them show the stratification phenomena and buoyancy force effects due to temperature difference and density variation. After certain times, depending on the case condition, the flow tends to reach a steady state.

关键词： turbulent flow realizablc k - e turbulence model heat transfer jet heat storage

Slip effects on shearing flows in a porous medium

在线全文

学校读者我要写书评

暂无评论

Acta mechanica Sinica 2008年第1期24卷 51-59页

作者： m.Khan T.Hayat Y.Wang Department of mathematics Quaid-i-Azam University Islamabad 44000 Pakistan chair of Fluid Dynamics Department of Mechanical Engineering Darmstadt University of TechnologyHochschulstrasse 164289 Darmstadt Germany

This paper deals with the magnetohydrodynamic （mHD） flow of an Oldroyd 8-constant fluid in a porous medium when no-slip condition is no longer valid. modified Darcy＇s law is used in the flow modelling. The non-linear differential equation with non-linear boundary conditions is solved numerically using finite difference scheme in combination with an iterative technique. Numerical results are obtained for the Couette, Poiseuille and generalized Couette flows. The effects of slip parameters on the velocity profile are discussed.

关键词： Porous medium. magnetohydrodynamic flow Slip effect

mesoporous WO_3-graphene photocatalyst for photocatalytic degradation of methylene Blue dye under visible light illumination

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2018年第4期30卷 328-337页

作者： Adel A.Ismail m.Faisal Adel Al-Haddad Wastewater Treatment and Reclamation Technologies (WTRT) Water Research Center Kuwait Institute for Scientific Research Advanced materials and Nano-Research Centre Najran University

Advanced oxidation technologies are a friendly environmental approach for the remediation of industrial wastewaters. Here, one pot synthesis of mesoporous WO3 and WO3-graphene oxide（GO） nanocomposites has been performed through the sol–gel method. Then, platinum（Pt） nanoparticles were deposited onto the WO3 and WO3-GO nanocomposite through photochemical reduction to produce mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites. X-ray diffraction（XRD） findings exhibit a formation of monoclinic and triclinic WO3 phases. Transmission Electron microscope（TEm） images of Pt/WO3-GO nanocomposites exhibited that WO3 nanoparticles are obviously agglomerated and the particle sizes of Pt and WO3 are ~ 10 nm and 20–50 nm, respectively. The mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites were assessed for photocatalytic degradation of methylene Blue（mB） as a probe molecule under visible light *** findings showed that mesoporous Pt/WO3, WO3-GO and Pt/WO3-GO nanocomposites exhibited much higher photocatalytic efficiencies than the pure WO3. The photodegradation rates by mesoporous Pt/WO3-GO nanocomposites are 3, 2 and 1.15 times greater than those by mesoporous WO3, WO3-GO, and Pt/WO3, respectively. The key factors of the enhanced photocatalytic performance of Pt/WO3-GO nanocomposites could be explained by the highly freedom electron transfer through the synergetic effect between WO3 and GO sheets, in addition to the Pt nanoparticles that act as active sites for O2 reduction, which suppresses the electron hole pair recombination in the Pt/WO3-GO nanocomposites.

关键词： mesoporous Pt/WO3 nanocomposites Graphene oxide methylene Blue photodegradation Visible light

Secured Cloud Data migration Technique by Competent Probabilistic Public Key Encryption

在线全文

学校读者我要写书评

暂无评论

China Communications 2020年第5期17卷 168-190页

作者： m.G.Aruna K.G.mohan Aassociate professor department of computer science and engineeringm s engineering collegeaffiliated to vtubengalurukarnataka562110india professor and head department of computer science and engineeringpresidency universitybengalurukarnataka560064india

Cloud computing, a recently emerged paradigm faces major challenges in achieving the privacy of migrated data, network security, etc. Too many cryptographic technologies are raised to solve these issues based on identity, attributes and prediction algorithms yet;these techniques are highly prone to attackers. This would raise a need of an effective encryption technique, which would ensure secure data migration. With this scenario, our proposed methodology Efficient Probabilistic Public Key Encryption(EPPKE) is optimized with Covariance matrix Adaptation Evolution Strategies(CmA-ES). It ensures data integrity through the Luhn algorithm with BLAKE 2b encapsulation. This enables an optimized security to the data which is migrated through cloud. The proposed methodology is implemented in Open Stack with Java Language. It achieves better results by providing security compared to other existing techniques like RSA, IBA, ABE, PBE, etc.

关键词： Luhn algorithm encryption efficient probabilistic public key encryption(EPPKE) covariance matrix adaptation evolution strategies(CmA-ES) trusted third party(TTP)

Enhancing mechanical behavior of micaceous soil with jute fibers and lime additives

在线全文

学校读者我要写书评

暂无评论

Journal of Rock mechanics and Geotechnical Engineering 2021年第5期13卷 1093-1100页

作者： J.Zhang A.Deng m.Jaksa School of Civil Environmental and Mining EngineeringThe University of AdelaideAdelaideSA5000Australia

micaceous soils are common in many tropical countries and regions,and in some locations with moderate *** soils are spongy and unstable when loaded and are not considered suitable as construction material in earth *** resolve the issue,this work examined performance of micaceous soil reinforced with a combination of jute fibers,hydrated lime or slag-lime.A total of 28 sample sets were prepared at various *** compression tests were conducted on the samples cured for 7 d and 28 d,*** test results suggested that the unconfined compressive strength(UCS)and material stiffness were increased with the inclusion of up to 1%fiber and decreased if additional fibers were *** ductility was improved consistently with up to 1.5%fiber *** inclusions of fibers combined with hydrated lime or slag-lime further enhanced strength and stiffness of micaceous soil,and the improvement depended on the dosages *** the dosages examined,jute fibers outweighed lime and slag in gaining ductility,and the optimal fiber content was 1%where strength and ductility were considered.

关键词： Geosynthetics Jute fiber Unconfined compressive strength(UCS) Stiffness

Corrosion behavior of magnesium and magnesium alloys

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2004年第1期14卷 1-10页

作者： I.m.Baghni 吴荫顺李久青张巍 mechanical Engineering Department Engineering College Tajoura Libya Corrosion & Protection Center University of Science and Technology Beijing Beijing 100083 China

The automotive industry has crossed the threshold from using magnesium alloys in interior applications such as instrument panels and steering wheels to unprotected environment such as oil pan, cylinder head and wheels. The expanding territory of magnesium leads to new challenges: mainly environmental degradation of the alloys used and how they can be protected. The present critical review is aimed at understanding the corrosion behavior of magnesium and magnesium alloys in industrial and marine environments, and the effect of microstructure, additive elements and inhibitors on the corrosion mechanism.

关键词：镁镁合金腐蚀显微结构汽车工业