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A New Analytical Expression for the Relationship Between the Charpy Impact Energy and Notch Tip Position for Functionally Graded Steels

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Acta Metallurgica Sinica(English Letters) 2013年第3期26卷 232-240页

作者： h.Samareh.salavati Pour F.Berto Y.Alizadeh Department of Mechanical Engineering Amirkabir University of Technology Shahid Chamran College of Kerman/Technical&Vocational University Department of Management and Engineering University of Padova

The effect of the distance between the notch tip and the position of the middle phase in the FGSs on the Charpy impact energy is investigated in the present paper. The results show that when the notch apex is close to the middle layer, the Charpy impact energy reaches its maximum value. This is due to the increment of the absorbed energy by plastic deformation ahead of the notch tip. On the other hand, when the notch tip is far from the middle layer, the Charpy impact energy strongly decreases. Another fundamental motivation of the present work is that for crack arrester configuration, no accurate mathematical or analytical modelling is available up to now. By considering the relationship between the Charpy impact energy and the plastic volume size, a new theoretical model has been developed to link the Charpy impact energy with the distance from the notch apex to the middle phase. This model is a simplified one and the effect of different shapes of the layers and the effect of microstructureon the mechanical properties and plastic region size will be considered in further investigation. The results of the new developed closed form expression show a sound agreement with some recent experimental results taken from the literature.

关键词： Charpy impact energy Functionally graded steel Crack divider configu- ration Crack arrester configuration

Mechanical responses of pristine and defective hexagonal boron-nitride nanosheets:A molecular dynamics investigation

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Frontiers of Structural and Civil Engineering 2020年第3期14卷 623-631页

作者： Mohammad salavati Arvin MOJAhEDIN Ali hossein Nezhad ShIRAZI Institute of Structural Mechanics Bauhaus-Universitat WeimarWeimar D-99423Germany

ABSTRACT In this work we conducted classical molecular dynamics(MD)simulation to investigate the mechanical characteristics and failure mechanism of hexagonal boron-nitride(h-BN)*** and defective structure of h-BN nanosheets were considered under the uniaxial tensile loadings at various *** defective structure contains three types of the most common initial defects in engineering materials that are known as cracks,notches(with various length/size),and point vacancy defects(with a wide range of concentration).MD simulation results demonstrate a high load-bearing capacity of extremely defective(amorphized)h-BN *** results also reveal that the tensile strength decline by increasing the defect content and temperature as *** MD results provide a comprehensive and useful vision concerning the mechanical properties ofh-BN nanosheets with/without defects,which is very critical for the designing of nanodevices exploiting the exceptional physics of h-BN.

关键词： hexagonal boron-nitride mechanical properties crack notch point defects molecular dynamics

Solvent-less synthesis of zinc oxide nanostructures from Zn(salen) as precursor and their optical properties

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Particuology 2012年第6期10卷 759-764页

作者： Ali Kazemi Babaheydari Masoud salavati-Niasari Afsaneh Khansari Islamic Azad University Shahrekord BranchShahre KordIran Institute of Nano Science and Nano Technology University of KashanP.O.Box 87317-51167KashanIran Department of Inorganic Chemistry Faculty of ChemistryUniversity of GuilanP.O.Box 413354-1914RashtIran

ZnO nanoparticles, 10-20 nm in size, were synthesized by heat treatment in air at 500 ℃ for 5 h., using [N,N＇-bis（salicylaldehydo） ethylene diamine]zinc（II）, i.e., Zn（salen）, as precursor, which was obtained by a solvent-flee solid-solid reaction. heat-treated products were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. Room temperature photoluminescence spectra of ZnO nanostructures are dominated by green emission attributed to oxygen vacancy related donor-acceptor transition.

关键词： ZnO Nanostructures Solvent-free synthesis Semiconductor

A controllable hydrothermal method to prepare La(Oh)_3 nanorods using new precursors

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Journal of Rare Earths 2015年第4期33卷 425-431页

作者： Mehdi Mousavi-Kamazani Sakineh Alizadeh Fateme Ansari Masoud salavati-Niasari Institute of Nano Science and Nano Technology University of Kashan

Using the hydrothermal method, lanthanum hydroxide nanorods were synthesized by the reaction of LaC13·7h20, ethyl- enediamine, and hydrazine. According to SEM results, ethylenediamine and hydrazine with ph management could control the parti- cle growth and played an important role in formation of lanthanum hydroxide nanorods. The morphology and microstructure of the obtained products were characterized by X-ray diffraction （XRD） spectra, energy-dispersive X-ray spectroscopy （EDX）, Fourier transformed infi＇ared （FTIR） spectrum, transmission electron microscopy （TEM）, and scanning electron microscopy （SEM）. Further- more, the effects of the molar ratio of the precursors as well as the reaction temperature and time on the morphology and particle size of the products were investigated.

关键词： nanorods hydrothermal lanthanum hydroxide one-dimensional rare earths

Structural and spectroscopic characterization of hgS nanoparticles prepared via simple microwave approach in presence of novel sulfuring agent

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Transactions of Nonferrous Metals Society of China 2016年第3期26卷 759-766页

作者： hossein SAFARDOUST-hOJAGhAN Maryam ShAKOURI-ARANI Masoud salavati-NIASARI Institute of Nano Science and Nano Technology University of KashanKashanP.O.Box 87317-51167Iran Department of Chemistry Payame Noor UniversityTehranP.O.Box 19395-3697Iran

Mercury sulfide (hgS) crystals with different morphologies and particle sizes, were obtained via a simple microwave reaction by a new precursor complex, [bis ((2-suphanylphenyl)imino]methylphenol) hg(II)] ([hg(C13h11NSO)2]2+). The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible (UV?Vis) spectroscopy. Mercury sulfide nanostructures with different sizes were prepared. The effects of precursor concentration, type of solvent, microwave time, and power on the particle size and morphology were investigated. The results show that the type of solvent and microwave power play key roles in the final size of hgS. Ethylene glycol is the best solvent for the synthesis of very fine particles of hgS, and the best power for the preparation of hgS nanoparticles with uniform size distribution is 900 W. The band gap for hgS nanoparticles calculated by UV–Vis spectrum was 3.2 eV which had about 1.2 eV blue shift in comparison with the band gap of 2 eV for bulk sample.

关键词： mercury sulfide microwave method nanostructures thio Schiff-base