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Plasma science and Technology 2022年第10期24卷 1-11页

作者： m R JAFARI mILANI s REZAEI m J JAFARI Photonics and Quantum Technologies Research school Nuclear Science and Technology Research InstituteTehran 14665-678Iran Plasma and Fusion Research school Nuclear Science and Technology Research InstituteTehran 14399-51113Iran

The generation of terahertz(THz)waves via the beating of two high-intensity chirped Gaussian lasers in a multi-ion-species plasma is numerically studied by taking into account the weak relativistic and ponderomotive regime of *** coupled differential equations for beamwidth parameters are extracted by introducing the dielectric function of such plasma and using WKB and paraxial ray *** amplitude of THz radiation at beat frequency resulting from the nonlinear current density induced by the beat ponderomotive force of the cross-focusing of beams was *** impacts of the chirp frequency parameter,initial laser intensity and initial ionic species density(specifically,the presence of singly and doubly charged ions)in the plasma on THz generation were *** numerical results reveal that THz radiation generation strongly depends on the chirp frequency parameter.A specific range of chirp frequencies exists for self-focusing as well as THz generation with a'turning point',where the THz emission reaches its maximum *** results show that the strength of self-focusing and consequently the generated THz radiation are reduced by increasing the density of doubly charged ionic species in the plasma due to the suppression of the nonlinear effects.

关键词： laser–plasma interaction THz generation chirped Gaussian laser beams

Effects of the phase variation and high-order momentum transfer components of NN amplitude on p-~4He elastic scattering

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Nuclear science and Techniques 2018年第1期29卷 65-76页

作者： I.m.A.Tag-Eldin m.m.Taha s.s.A.Hassan Nuclear Experimental Physics Department Nuclear Research Center Atomic Energy Authority mathematics and Theoretical Physics Department Nuclear Research Center Atomic Energy Authority

Elastic scattering differential cross sections for a p- ~4He system are calculated within the framework of optical limit approximation of the Glauber multiple scattering model. Three different ranges for proton energy(E_(lab)), 19〈E_(lab)〈50 me V, 100≤E_(lab)≤1730 me V, and 45 ≤E_(lab)≤393 Ge V are considered. It is shown that the Pauli blocking fails to describe the data up to the proton energy, E_(lab)〈100 me V. For higher proton energies, a qualitative agreement is obtained. The observed elastic scattering differential cross section is nicely reproduced in the whole range of scattering angles in the center of mass system up to Θ_(c.m.)〈200° for 19〈E_(lab) ≤100 me V when the effect of both the nucleon–nucleon(NN) phase variation parameter γNN and higher-order momentum transfer components(λ_n; n = 1 and 2) of(NN) elastic scattering amplitude is included. In the range of 200 E_(lab) 1730 me V, introducing λ_n plays a significant role in describing the data up to the momentum transfer, q^2≤1:2(Ge V/c)~***, it is found that considering only the effect of phase variation parameter, cNN, improved the agreement in the region of minima for elastic scattering differential cross section for 45≤E_(lab)≤393 Ge V. The values of cNNand kn as a function of incident proton energies are presented.

关键词： Elastic scattering Optical limit approximation Glauber multiple scattering model

Direct microwave leaching conditions of rare earth elements in fluorescent wastes

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Journal of Rare Earths 2024年第6期42卷 1165-1174,I0007页

作者： A.Bilen B.Birol m.N.saridede s.s.Kaplan m.s.sonmez Department of metallurgical and materials Engineering Yildiz Technical UniversityIstanbulTurkey Department of Chemical Engineering and materials science Stevens Institute of TechnologyNew JereyUSA Department of metallurgical and materials Engineering Istanbul Technical UniversityIstanbulTurkey

The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s *** can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth *** the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent *** the yields were *** the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)sO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were *** highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(s:L),and 90 *** energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction ***,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed ***,mathematical models of all experimental studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.

关键词： Rare earth elements(REEs) Direct microwave leaching Fluorescent waste Kinetic models Response surface method

New Aspects of Field Entropy squeezing as an Indicator for mixed state Entanglement in an Effective Two-Level system with stark shift

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Chinese Physics Letters 2011年第12期28卷 24-27页

作者： s.Abdel-Khalek m.m.A.Ahmed A-s F.Obada Department of mathematics Faculty of ScienceSohag University82524 SohagEgypt Department of mathematics Faculty of ScienceTaif University21974 TaifSaudi Arabia Department of mathematics Faculty of ScienceAl-Azhar UniversityNasr City11884 CairoEgypt

We present an effective two-level system in interaction through two-photon processes with a single mode quantized electromagnetic field,initially prepared in a coherent *** entropy squeezing as an indicator of the entanglement in a mixed state system is *** temporal evolution of the negativity,Wehrl entropy,Wehrl phase distribution and field entropy squeezing are *** results highlight the important roles played by both the stark shift parameters and the mixed state setting in the dynamics of the Wehrl entropy,Wehrl phase distribution and field entropy squeezing.

关键词： state entropy system

Crashworthiness performance of hybrid kenaf/glass fiber reinforced epoxy tube on winding orientation effect under quasi-static compression load

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Defence Technology（防务技术） 2020年第5期16卷 1051-1061页

作者： A.B.m.supian s.m.sapuan m.Y.m.Zuhri E.s.Zainudin H.H.Ya Advanced Engineering materials and Composites Research Centre Department of Mechanical and Manufacturing EngineeringUniversiti Putra Malaysia43400UPM SerdangSelangorMalaysia Laboratory of Biocomposite Technology Institute of Tropical Forestry and Forest Products(INTROP)Universiti Putra Malaysia43400UPM SerdangSelangorMalaysia Department of mechanical Engineering Universiti Teknologi Petronas32610Seri IskandarPerakMalaysia

This research was aimed to study the effect winding orientation on the crashworthiness performance of hybrid *** specimens tested under quasi-static compression load involve of three winding parameters(q?30,45and 70)of hybrid kenaf/glass fiber reinforced epoxy and glass fiber reinforced epoxy as contrast *** automated filament winding technique has been used in fabrication of hybrid and non-hybrid composite tube and crashworthiness performance was investigated *** effects of winding orientation on energy absorption capabilities and crashworthiness characteristic were investigated through quasi-static compression load and the result are compared with the glass fiber composite tube to justify the capability of hybrid natural/synthetic as energy absorption *** samples proved to enhancing the progressive crushing capability as combination of local buckling,delaminate and brittle fracturing as progressive crushing *** the view of winding orientation aspect,the results of high winding orientation of hybrid composite tube elevated the crush load efficiency,specific energy absorption and energy absorption capability compared to glass composite tube(GFRP).The hybrid kenaf/glass composite tube with high winding orientation showed the best winding orientation to enhance the energy absorber characteristics as energy absorption application.

关键词： composite laminate winding

Nanosized complex fluorides based on Eu^(3+) doped sr_2LnF_7(Ln=La, Gd)

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Journal of Rare Earths 2014年第3期32卷 242-247页

作者： m.Runowski s.Balabhadra s.Lis Department of Rare Earths Faculty of Chemistry Adam Mickiewicz University

A simple co-precipitation approach taking place between Ln3＋, sr2＋ cations and F anions, led to the formation of nanocrystalline Eu3＋ doped sr2LnF7 （Ln-La and Gd） complex fluorides. The reaction was carried out in the presence of polyeth- ylene glycol, PEG 6000 as a surfactant/surface modifier, providing small size and homogeneity of the products. The synthesized compounds were composed of small nanoparticles with an average size of 15 nm. All obtained Eu3＋ doped compounds exhibited an intensive red luminescence. In the case of gadolinium based compounds, the energy transfer phenomena could be observed from Gd3＋ ions to Eu3＋ ions. In order to study the structure and morphology of the synthesized fluorides, powder X-ray diffraction （XRD） and transmission electron microscopy （TEm） measurements were performed. Also FT-IR spectra of the products were re- corded, revealing the presence of PEG molecules on the nanoparticles suN＇ace. A spectrofluorometry technique was applied to examine optical properties of the synthesized nanoparticles. Excitation and emission spectra as well as luminescence decay curves were measured and analysed. The performed analysis revealed a red luminescence, typical for the Eu3＋ ion situated in the inorganic, highly symmetric matrix. Concentration quenching phenomena and lifetimes shortening, together with an increasing of the Eu3＋ doping level, were observed and discussed. Judd-Ofelt analysis was also performed for all doped samples, in order to support the registered spectroscopic data and examine in details structural and optoelectronic properties of the synthesized nanomaterials.

关键词： luminescence Eu3+ doping complex strontium lanthanide fluorides nanoparticles sr2LnF7 sr0.69La0.31F2.31 rare earths

Interactions of ion acoustic multi-soliton and rogue wave with Bohm quantum potential in degenerate plasma

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Chinese Physics B 2017年第9期26卷 301-309页

作者： m s Alam m G Hafez m R Talukder m Hossain Ali Department of Applied mathematics University of RajshahiRajshahi-6205Bangladesh Plasma science and Technology Lab Department of Applied Physics and Electronic EngineeringUniversity of RajshahiRajshahi-6205Bangladesh Department of mathematics Chittagong University of Engineering and TechnologyChittagong-4349Bangladesh

This work investigates the interactions among solitons and their consequences in the production of rogue waves in an unmagnetized plasmas composing non-relativistic as well as relativistic degenerate electrons and positrons, and inertial non-relativistic helium ions. The extended Poincare′–Lighthill–Kuo（PLK） method is employed to derive the two-sided Korteweg–de Vries（KdV） equations with their corresponding phase shifts. The nonlinear schrodinger equation（NLsE） is obtained from the modified Kd V（mKdV） equation, which allows one to study the properties of the rogue waves. It is found that the Fermi temperature and quantum mechanical effects become pronounced due to the quantum diffraction of electrons and positrons in the plasmas. The densities and temperatures of the helium ions, degenerate electrons and positrons, and quantum parameters strongly modify the electrostatic ion acoustic resonances and their corresponding phase shifts due to the interactions among solitons and produce rogue waves in the plasma.

关键词： wave-wave interaction rogue waves degenerate plasmas Bohm potential

Thermal bleaching of optical absorption and photoluminescence spectra of γ-irradiated CaF_2:Dy:Pb:Na single crystals

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Journal of Rare Earths 2010年第4期28卷 493-497页

作者： s.m. moses Kennedy Department of Physics S.S.N. College of Engineering Rajiv Gandhi Salai Kalavakkam-603 110 Chennai Tamil Nadu India

The variation of the optical absorption (OA) and photoluminescence (PL) spectra with temperature was studied on γ-irradiated CaF2:Dy:Pb:Na single crystals. The OA spectrum showed bands around 2.05, 3.20, 3.82 and 6.20 eV which could be attributed to different sodium associated (sA) colour centres (CCs) such as mNa and RA+ . Heating the crystal indicated the annihilation and formation of different sACCs. The excitation spectrum for the characteristic Dy3+ emission at 2.14 eV immediately after irradiation was...

关键词： calcium fluoride optical absorption photoluminescence colour centres dysprosium lead sodium rare earths

Linear Precoder Design for Correlated Rician Fading Channel Under Imperfect CsI

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China Communications 2023年第9期20卷 160-170页

作者： s.B.m.Priya school of Electrical and Electronics Engineering SASTRA Deemed UniversityThanjavur 613401India

In this paper,we have modeled a linear precoder for indoor multiuser multiple input multiple output(mU-mImO)system with imperfect channel state information(CsI)at *** Rician channel is presumed to be mutually coupled and spatially,temporarily *** imperfection with CsI is primarily due to the channel estimation error at receiver and feedback delay amidst the receiver and transmitter in CsI *** with,the insufficient spacing between the antenna at transmitter and receiver persuades mutual coupling(mC)among the array *** addition,the mImO channel is presumed to be jointly correlated(Weichselberger correlation model).When we look back on the existing precoder design,it considered spatial correlation alone disregarding joint correlation of antenna array *** all above assumption,we have designed a linear precoder which minimizes mean squared error(msE)subjected to total transmit power constraint for mUmImO *** simulation results proven that proposed precoder shows substantial enhancement in bit error rate(BER)performance in comparison with the existing *** mathematical analysis corroborates the simulation results.

关键词： channel estimation error feedback delay mmsE linear precoder mutual coupling spatial cor-relation Weichselberger correlation model

Orderly decorated nanostructural photoelectrodes with uniform spherical TiO2 particles for dye-sensitized solar cells

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Frontiers of Chemical science and Engineering 2015年第4期9卷 532-540页

作者： A.m. Bakhshayesh s.s. Azadfar Department of Research and Development SUN Nanotechnologists Company Tehran 13488-96394 Iran

This study presents a novel nanostructural electrode made of 20-nm-diameter nanoparticles, which orderly decorated with 2-μm TiO2 particles, deposited by a new gel process. The decorated electrode （DE） is better than the non-decorated electrode （NE） in both light scattering and light harvesting, as confirmed by diffuse reflectance spectroscopy. X-ray diffraction reveals that both electrodes have a mixture of anatase and rutile phases. The dye-sensitized solar cell based on the decorated electrode shows the highest power conversion efficiency of 7.80% as a result of less recombination demonstrated by electrochemical impedance spectroscopy. From internal power conversion efficiency measurement, the external quantum efficiency of DE cell at 530 nm is 89%, which is higher than that of NE cell （77%）.

关键词： dye-sensitized solar cell uniform particles,TiO2 gel process light harvesting