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Structural,electronic,magnetic and optical properties of neodymium chalcogenides using LSdA+U method

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Journal of Semiconductors 2012年第8期33卷 9-14页

作者： A Shankar d p rai Sandeep R K Thapa Condensed Matter Theory Group Department of PhysicsMizoram UniversityAizawlMizoram-796004India

We have studied the electronic, magnetic and optical properties of neodymium chalcogenides by performing LSdA＋ U and full potential linearized augmented plane wave （Fp-LApW） method. The electronic structure calculation shows that the electronic states in Nd-chalcogenides were mainly contributed by Nd-4f electrons near Fermi energy and 3p, 4p and 5p state electrons of X （S, Se and Te）, respectively. We have also studied the absorption of light via the imaginary parts of the dielectric function of Nd-chalcogenides.

关键词： dFT dOS magnetic moment U

Band-gap engineering of La1-xNdxAlO3(x = 0,0.25,0.50,0.75,1)perovskite using density functional theory：A modified Becke Johnson potential study

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Chinese physics B 2016年第6期25卷 376-382页

作者： Sandeep d p rai A Shankar M p Ghimire Anup pradhan Sakhya T p Sinha R Khenata S Bin Omran R K Thapa department of physics Mizoram University Aizawl-796004 India department of physics Pachhunga University College Aizawl-796001 India department of physics University of North Bengal Darjeeling-734013 India IFW dresden e. V. P. O. Box 270116 D-01171 Dresden Germany department of physics Bose Institute 93/1 Acharya Prafulla Chandra Road Kolkata 700009 India Laboratoire de physique Quantique et de Modelisation Mathematique (LpQ3M) Department de Technologie Universite de Mascara 29000 Mascara Algerie Algeria department of physics and Astronomy College of Science King Saud University P. O: Box 2455 Riyadh 11451 Saudi Arabia

The structural,electronic,and magnetic properties of the Nd-doped Rare earth aluminate,La1-xNdxAlO3（x = 0%to 100%） alloys are studied using the full potential linearized augmented plane wave（Fp-LApW） method within the density functional *** effects of the Nd substitution in La AlO3 are studied using the supercell *** computed electronic structure with the modified Becke–Johnson（m BJ） potential based approximation indicates that the La1-xNdxAlO3 alloys may possess half-metallic（HM） behaviors when doped with Nd of a finite density of states at the Fermi level（EF）.The direct and indirect band gaps are studied each as a function of x which is the concentration of Nddoped La *** calculated magnetic moments in the La1-xNdxAlO3 alloys are found to arise mainly from the Nd-4f state.A probable half-metallic nature is suggested for each of these systems with supportive integral magnetic moments and highly spin-polarized electronic structures in these doped systems at *** observed decrease of the band gap with the increase in the concentration of Nd doping in La AlO3 is a suitable technique for harnessing useful spintronic and magnetic devices.

关键词： density functional theory rare earth aluminates perovskites electronic structures

Optoelectronic and thermoelectric properties of Zintl YLi_(3)A_(2)(A = Sb,Bi) compounds through modified Becke-Johnson potential

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Chinese physics B 2016年第10期25卷 428-435页

作者： T Seddik G Ugur R Khenata S Ugur F Soyalp G Murtaza d p rai A Bouhemadou S Bin Omran department of physics and Astronomy College of ScienceKing Saud UniversityP.O.Box 2455Riyadh 11451Saudi Arabia

In the present work,we investigate the structural,optoelectronic and thermoelectric properties of the YLi3X2(X = Sb,Bi) compounds using the full potential augmented plane wave plus local orbital(Fp-ApW+lo) *** exchangecorrelation potential is treated with the generalized gradient approximation/local density approximation(GGA/LdA) and with the modified Becke-Johnson potential(TB-mBJ) in order to improve the electronic band structure *** addition,the estimated ground state properties such as the lattice constants,external parameters,and bulk moduli agree well with the available experimental *** band structure calculations with GGA and LdA predict that both compounds have semimetallic ***,the band structure calculations with the GGA/TB-mBJ approximation indicate that the ground state of the YLi3Sb2compound is semiconducting and has an estimated indirect band gap(Γ-L) of about 0.036 eV while the ground state of YLi3Bi2compound is *** the LdA/TB-mBJ calculations indicate that both compounds exhibit semiconducting characters and have an indirect band gap(Γ-L) of about 0.15 eV and 0.081 eV for YLi3Sb and ***,the optical properties reveal strong responses of the herein materials in the energy range between the IR and extreme UV *** properties such as thermal conductivity,electrical conductivity,Seebeck coefficient,and thermo power factors are also calculated.

关键词： Zintl compounds TB-mBJ electronic band-structure optical properties thermoelectric properties

Characteristics of Emission Non-nulling pulsars Through Simulation

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Research in Astronomy and Astrophysics 2024年第4期24卷 91-102页

作者： rai Yuen Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Xinjiang Key Laboratory of Radio Astrophysics Chinese Academy of SciencesUrumqi 830011China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210008China SIfA School of PhysicsUniversity of SydneySydneyNSW2006Australia

We investigate the population and several properties of radio pulsars whose emission does not null(non-nulling)through simulation of a large pulsar *** from a pulsar is identified as non-nulling if(i)the emission does not cease across the whole pulse profile,and(ii)the emission is ***(i),we adopt a model for switching in the plasma charge density,and emission persists if the charge density is ***(ii),we assume that detectable emission originates from source points where it is emitted tangentially to the magnetic field-line and parallel to the *** find that pulsars exhibiting non-nulling emission possess obliquity angles with an average of 42°.5,and almost half the samples maintain a duty cycle between 0.05 and ***,the pulsar population is not fixed but dependent on the obliquity angle,with the population peaking at 20°.In addition,three evolutionary phases are identified in the pulsar population as the obliquity angle evolves,with the majority of samples having an obliquity angle between 20°and 65°.Our results also suggest that emission from a pulsar may evolve between nulling and non-nulling during its lifetime.

关键词： radiation mechanisms:non thermal stars:neutron (stars:)pulsars:general

paper Analytical device for the Colourimetric detection of Alkaline phosphatase in Serum and Saliva

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Journal of Analysis and Testing 2024年第03期8卷 385-394页

作者： d.Alageswari A.Lakshmidevi p.E.Resmi p.V.Suneesh Aarathipradeep T.G.SatheeshBabu department of Chemistry Amrita School of Physical Sciences Coimbatore Amrita Vishwa Vidyapeetham Amrita Biosensor Research Lab Amrita School of Engineering Coimbatore Amrita Vishwa Vidyapeetham Amrita Biomedical Engineering Centre Amrita School of Engineering Coimbatore Amrita Vishwa Vidyapeetham

A paper analytical device (pAd) was developed for the colourimetric estimation of alkaline phosphatase (ALp). ALp catalyzes the hydrolysis of disodium phenyl phosphate (dSpp) to phenol, which then undergoes oxidative coupling with4-aminoantipyrine (4-AAp) producing a reddish brown-coloured quinone imine. The colourimetric reaction tested in solution has been translated onto a pAd for the point of care (poC) testing of ALp. A uniform colour was obtained in 25 min with the introduction of ALp onto the reagent drop cast paper device. The images obtained by scanning the pAd were processed using ImageJ software. The colour intensity obtained by image processing was proportional to the concentration of ALp present in the sample. ALp in serum and saliva samples were tested using the pAd in the range of 0 to 528 U/L and0 to 187 U/L, respectively. The interference studies revealed that the pAd was selective to ALp in the presence of other biomolecules. The pAd exhibited a limit of detection (LOd) of 3.3 U/L and a sensitivity of 48.36 a.u/Log(U/L) for serum ALp and LOd of 1.69 U/L and a sensitivity of 28.5 a.u/Log (U/L) for salivary ALp. The pAd showed good agreement with the clinical methods for real samples.

关键词： Alkaline phosphatase Colourimetry ImageJ paper analytical device point of care testing

Numerical analysis of high‑speed railway slab tracks using calibrated and validated 3d time‑domain modelling

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railway Engineering Science 2024年第1期32卷 36-58页

作者： A.F.Esen O.Laghrouche p.K.Woodward d.Medina‑pineda Q.Corbisez J.Y.Shih d.p.Connolly Institute for High‑Speed rail and System Integration University of LeedsLeeds LS29JTUK Institute for Infrastructure and Environment Heriot-Watt UniversityEdinburgh EH144ASUK Alstom Transport Saint‑OuenFrance Birmingham Centre for railway Research and Education University of BirminghamBirmingham B152TTUK

Concrete slabs are widely used in modern railways to increase the inherent resilient quality of the tracks,provide safe and smooth rides,and reduce the maintenance *** this paper,the elastic performance of a novel slab trackform for high-speed railways is investigated using three-dimensional finite element modelling in *** is then compared to the performance of a ballasted ***,slab and ballasted track models are developed to replicate the full-scale testing of track *** the models are calibrated with the experimental results,the novel slab model is developed and compared against the calibrated slab track *** slab and ballasted track models are then extended to create linear dynamic models,considering the track geodynamics,and simulating train passages at various speeds,for which the Ledsgard documented case was used to validate the *** travelling at low and high speeds are analysed to investigate the track deflections and the wave propagation in the soil,considering the issues associated with critical *** train loading methods are discussed,and the most practical approach is retained and ***,correlations are made between the geotechnical parameters of modern high-speed rail and conventional *** is found that considering the same ground condition,the slab track deflections are considerably smaller than those of the ballasted track at high speeds,while they show similar behaviour at low speeds.

关键词： High-speed railways Slab track New ballastless track Ballasted track Critical speeds Finite element modelling Calibration of numerical models

Temperature and structure measurements of heavy-ion-heated diamond using in situ X-ray diagnostics

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Matter and Radiation at Extremes 2024年第4期9卷 80-89页

作者： J.Lutgert p.Hesselbach M.Schorner V.Bagnoud R.Belikov p.drechsel B.Heuser O.SHumphries p.Katrik B.Lindqvist C.Qu R.Redmer d.Riley G.Schaumann S.Schumacher A.Tauschwitz d.Varentsov K.Weyrich X.Yu B.Zielbauer Zs.Major p.Neumayer d.Kraus Institut fur physik Universitat RostockAlbert-Einstein-Str.2318059 RostockGermany GSI Helmholtzzentrum fur Schwerionenforschung Planckstr.164291 DarmstadtGermany Institut für Angewandte physik Goethe-Universität Frankfurt am MainMax-von-Laue-Str.160438 Frankfurt am MainGermany Institut fur Geowissenschaften Goethe-Universitat Frankfurt am MainAltenhoferallee 160438 Frankfurt am MainGermany Helmholtz-Zentrum dresden-Rossendorf Bautzner Landstr.40001328 DresdenGermany European XFEL GmbH Holzkoppel 422869 SchenefeldGermany Centre for plasma physics School of Mathematics and PhysicsQueen’s University BelfastUniversity RoadBelfast BT71NNUnited Kingdom Institut für Kernphysik Technische Universität DarmstadtSchlossgartenstr.964289 DarmstadtGermany State Key Laboratory of Nuclear physics and Technology Institute of Heavy Ion PhysicsPeking UniversityBeijing 100871China Helmholtz Institut Jena Frobelstieg 307743 JenaGermany

We present in situ measurements of spectrally resolved X-ray scattering and X-ray diffraction from monocrystalline diamond samples heatedwith an intense pulse of heavy *** this way,we determine the samples’heating dynamics and their microscopic and macroscopic structuralintegrity over a timespan of several *** the ratio of elastic to inelastic scattering with state-of-the-art density functionaltheory molecular dynamics simulations allows the inference of average temperatures around 1300 K,in agreement with predictions fromstopping power *** simultaneous diffraction measurements show no hints of any volumetric graphitization of the material,butdo indicate the onset of fracture in the diamond *** experiments pave the way for future studies at the Facility for Antiproton andIon Research,where a substantially increased intensity of the heavy ion beam will be available.

关键词： heated intense structure

Exploring one material for dual applications:A red-emitting Mg2GeO4:Eu3+ nanophosphor for future generation energy efficient WLEds and dosimetric applications

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Journal of Rare Earths 2024年第10期42卷 1835-1845页

作者： Akshay Arjun G.p.darshan S.C.Sharma H.Nagabhushana d.V.Sunitha H.B.premkumar department of physics Faculty of Mathematical and Physical SciencesM.S.Ramaiah University of Applied Sciences Jain University C.N.R.Rao Centre for Advanced Materials Tumkur University School of Applied Sciences (physics) REVA University

The envisaged design and developme nt of individual mate rials to excavate a broader spectrum of desired properties and offer multiple applications are highly *** this in mind,a series of forsterite-structured Mg2GeO4:Eu3+（1 mol%-9 mol%） nanophosphors was synthesized via a solution combustion method using oxalyl dihydrazide as a *** X-ray diffraction patterns confirm the orthorhombic crystal system with a puma space *** results clearly show irregularly shaped cluster-like structures with aggregation of the *** diffuse reflectance spectra,the optical energy band gap of the Mg2GeO4:Eu3+（1 mol%-9 mol%） nanophosphors was estimated and obtained to be～4.12-4.32 *** photoluminescence emission spectra exhibit intense peaks at ～579,589,610,661,and 707 nm,which are due to characteristic5d0→7F0,5d0→7F1,5do→7F2,5d0→7F3and5d0→7F4transitions of Eu3+ions,*** Commission International de L'Eclairage color coordinates are gradually tuned from pale red（0.5980,0.4012） to a pure red（0.6385,0.3611） *** glow peaks showcase excellent super-linear response at low doses of γ-irradiations,indicating that the prepared phosphor can be used in thermoluminescent personal dosimetry which is a biological tissue *** aforementioned results demonstrate that the prepared Mg2GeO4:Eu3+（1 mol%-9 mol%） nanophosphors are considered an excellent candidate for dual applications,i.e.,red component in future generation white-light-emitting diodes（WLEds） and personal dosimetric applications.

关键词： dosimetry Nanophosphors photoluminescence photometric properties Rare earths Thermoluminescence

Solid-liquid extraction for yttrium recovery using porous polymeric resin(XAd-7) functionalized with d_(2)EHpA

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Journal of Rare Earths 2024年第9期42卷 1764-1773,I0005页

作者： p.A.Martínez-Montoya R.G.Sanchez-Alvarado d.Y.Medina-Velazquez M.L.Carrera-Jota p.Garnica-Chávez A.de J.Morales-Ramirez Higher School of Chemical Engineering and Extractive Industries ESIQIEIPNDepartment of Metallurgical EngineeringUPALM S/NCol.LindavistaGustavo A.Madero Cd.de MéxicoC.P07738Mexico Metropolitan Autonomous University Department of MaterialsBasic Sciences and EngineeringAv.San Pablo No.180Col.Reynosa TamaulipasCd.de MéxicoC.P02200Mexico Center for Research and Technological Innovation CIITECIPNCda.de CECATIs/nSanta CatarinaAzcapotzalcoC.P02250CDMXMexico

The recovery of yttrium is proposed by applying a solid-liquid extraction process using di-2-ethyl hexylphosphoric acid(d2EHpA) as extracting *** extracting agents were supported on a macro porous polymeric resin XAd-7(solid phase).Yttrium ions extraction and discharge tests were performed,firstly from a synthetic aqueous solution of 100 mg/L Y(liquid phase) at 25℃ with *** effects of pH of aqueous solutions bearing yttrium,volume fraction of extracting agents and the solid/liquid(S/L)ratio on the yttrium recovery were *** most favorable conditions for yttrium ions extraction are;20 vol% d_(2)EHpA functionalized resin,pH=1.5 and an S/L ratio of 10 mg/mL The discharge of yttrium ions was done under the same conditions of extraction stage,using a 2 mol/L [H_(2)SO_(4)] as stripping *** to 80% yttrium is extracted,while 75% yttrium is recovered in the striping *** all experiments,the reaction equilibrium is reached after 20 min,and the kinetics for the extraction stage was determined as a second-order ***,experiments were carried out to discharge the yttriumloaded resins,and it has been determined that the best pH value to strip the Y ions is *** tests of extraction and discharge for yttrium ions show that the functionalized resin can work at least five cycles without decreasing its ***,the proposed process was tested in a real solution with Y ions fro m a waste fluorescent la mp powder leached in H_(2)SO_(4),demonstrating the ability to effectively recover yttrium,separating it from various metals from the studied residue.

关键词： Yttrium recovery Rare earth solid-liquid extraction XAd-7 resin Fluorescent lamps recycling Solid-liquid kinetics extraction