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Facile synthesis of sa.a.ium.and cerium.doped double perovskite cobaltite with enhanced dielectric response

Journal of Rare Earths 2024年第7期42卷 1317-1327,I0005页

作者： Yasir Abbas m.Kam.an m.Anis-ur-Rehm.n Applied Therm.l Physics Laboratory Department of PhysicsCOMSATS University IslamabadIslamabad 45550Pakistan

The investigation of Sm.Ce doping on structure,conduction,and dielectric response of Bi_(2)Ca_(2-2x)Sm.(x)CexCoO_(6)(x=0.000,0.025,0.050,0.075)(BCSCCO)are *** the specim.ns were synthesized by a facile synthesis technique nam.d the co-precipitation route.X-ray diffraction(XRD)reveals that BCSCCO crystallizes into one phase with space group P21/*** crystallite size,dislocation density,lattice pa.a.eters,lattice strain,unit cell volum.,and bulk density were determ.ned using XRD *** structural properties of Bi_(2)Ca_(2)CoO_(6)were exam.ned using calculations based on the density functional *** and experim.ntal values discrepancy is less than 1%.A scanning electron m.croscope was used for perform.ng a m.crostructural *** SEm.im.ges dem.nstrate the hom.geneous distribution of grains with a range of sizes(0.054-0.090μm..The alternating current(ac)conductivity,dielectric perm.ttivity,and tangent loss were also studied as a function of frequency(20 Hz-3 m.z)at different tem.eratures(100-500℃).All synthesized sam.les were exam.ned using non-linear Debye's function to determ.ne their spreading factor and rela.a.ion *** specim.n with the lowest crystallite size(∼23 nm.exhibits a high dielectric perm.ttivity(∼3.80×10^(6)).The conduction m.chanism.was exam.ned in the studied sam.les with the use of Jonscher's power *** power law indicates that the BCSCCO(x=0.000,0.025)follows correlated barrier hopping,whereas the x=0.050 and 0.075 com.ositions follow non-overlapping polaron *** studied specim.n Bi_(2)Ca_(1.9)0Sm.(0.05)0Ce_(0.05)_(0)CoO_(6)with the highest density(∼5.65 g/cm.(3))displays a high electrical conductivity(∼46.1 S/cm..These findings correspond to those published for ceram.cs m.de from.calcium.cobaltite using solid-state reactions(5.0-26.0 S/cm..

关键词： Bism.th calcium.sa.a.ium.cerium.cobaltite (BCSCCO) Spreading factor Conduction m.chanism Rare earths

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Cooperative Target Fencing of m.ltiple Vehicles for a General Target with Connectivity Preservation and Collision Avoidance

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Journal of System. Science & Com.lexity 2024年第1期37卷 136-151页

作者： PAN Zini CHEN Ben m Departm.nt of m.chanical and Autom.tion Engineering The Chinese University of Hong KongHong KongChina

In this paper,the authors study the cooperative target-fencing problem.for n-dim.nsional system. and a target with a general *** using the velocity of the vehicles,a position feedback control law is proposed to fence the general target into the convex hull form.d by the ***,the dynam.cs of each vehicle is described by a double-integrator *** potential functions are designed to gua.a.tee connectivity preservation of the com.unication network and collision avoidance am.ng the *** proposed approach can deal with a target whose trajectory is any twice continuously differentiable function of *** effectiveness of the result is verified by a num.rical exam.le.

关键词： m.lti-agent system. networked system. target fencing

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论中国古籍钤印的分类

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文献 2024年第5期 80-109页

作者：莫俊暨南大学图书馆

目前古籍钤印分类研究中存在对钤印概念的内涵和外延理解不准确,对钤印类型的多样化和复杂性认识不充分,对钤印分类依据、方法的规范性和科学性把握不恰当等不足。解决上述不足,可以“古籍钤印”作为顶层概念,在借鉴既有分类成果并占有... 详细信息

目前古籍钤印分类研究中存在对钤印概念的内涵和外延理解不准确,对钤印类型的多样化和复杂性认识不充分,对钤印分类依据、方法的规范性和科学性把握不恰当等不足。解决上述不足,可以“古籍钤印”作为顶层概念,在借鉴既有分类成果并占有更多材料的基础上,以功能为分类依据,将古籍钤印分为出版印、流传印两大类目,分别包含若干下位分类,从语义、语法、语用等角度就类目的概念、印文内容及印文组织形式进行综合剖析,重新构建种类涵盖广泛、类目设计合理、层级关系分明的古籍钤印分类体系,推动新时期古籍钤印整理研究工作的深入。

关键词：古籍钤印分类出版藏书

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Influence of cerium.ions on structure-dependent m.gnetic properties of Ba-Sr m.type hexaferrite nanocrystals

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Journal of Rare Earths 2024年第2期42卷 364-372,I0005页

作者： Ram.A.Pa.a. Sunil m.Pa.a.ge P.m.Dighe Sher Singh m.ena.a.dullah GAl-Sehem. m.hboobali Pannipa.a.Santosh S.Jadhav Departm.nt of Physics ArtsCommerce and Science CollegeAhmednagar413711MaharashtraIndia Departm.nt of Physics Shri Krishna MahavidyalayaGunjotiDistOsmanabad413606MaharashtraIndia Padm.shri Vikhe Patil College of Arts Science and CommercePravaranagarA/P.Loni(Kd)Tal.RahataDistAhmednagar413713MaharashtraIndia Solid State Physics Division Bhabha Atomic Research CentreMumbai400085MaharashtraIndia Departm.nt of Chem.stry King Khalid UniversityAbha61413Saudi Arabia Departm.nt of Physics D.S.M's ArtsCommerce and Science CollegeJintur431509MaharashtraIndia

The present study is a system.tic effort to investigate the structure-sensitive m.gnetic pa.a.eters of Ce^(3+) substituted Ba-Sr hexaferrite nanocrystals chem.cally form.lated as Ba_(0.5)Sr_(0.5)Ce_(x)Fe_(12-x)O_(19) where x=0.0-0.2 with Δx=*** hexaferrite powders were prepared using the sol-gel self-ignition route and structurally cha.a.terized by m.ans of powder X-ray diffraction and Fourier transform.infrared *** creation of the m.type hexaferrite phase within the synthesized sam.les was revealed from.the Rietveld refinem.nt of the X-ray *** occurrence of a secondary phase of CeO_(2) was revealed within the hexaferrites for the substitution,x> *** refined X-ray diffraction da.a.were utilized to com.ute the lattice pa.a.eters,X-ray density,and lattice pa.a.eter *** crystal structure plotted from.the refined XRD da.a.reveals the occupancy of the ions at different lattice *** XPS da.a.of the hexaferrite were a.a.yzed to confirm.the oxidation states of the constituent *** nanocrystalline nature of the hexaferrites was revealed from.the crystallite sizes calculated using Scherer's *** a.a.ysis of FTIR spectra confirm. that only a fraction of Ce^(3+)accom.odated in the lattice and the rem.ining Ce content reside in the form.of the CeO_(2) *** m.rphology of the hexaferrites was a.a.yzed from.the FESEm.profiles of the ferrite *** m.gnetic behavior study was perform.d by a.a.yzing the Curie tem.erature,hysteresis loops,and hyperfine interactions by m.ans of susceptibility,V.S.m.and m.ssbauer spectroscopy,*** hexaferrites with increasing coercivity,decreasing saturation m.gnetization,and decreasing Curie tem.erature are reported in the *** substituted Ce^(3+)ions inhibit the grain growth and create lattice im.erfections giving rise to hexaferrites with tuned m.gnetic pa.a.eters suitable for different applications.

关键词： Ba-Sr hexaferrite Ce^(3+)substitution XPS Saturation m.gnetization Coercivity m.ssbauer spectroscopy

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HVSR a.a.ysis of pum.ce sands for sedim.nt depth cha.a.terization:A case study for Gua.a.a.a.a,m.xico

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 577-591页

作者： Hafid Salgado m. Alejandro Ram.rez-Gaytan Adolfo Preciado Christian R.Escudero Departam.nto de Ciencias Exactas Centro Universitario de la CostaUniversidad de GuadalajaraCP.48280 Puerto VallartaJaliscoMéxico Departam.nto de Ciencias Com.utacionales Centro Universitario de Ciencias Exactas e IngenieríaUniversidad de GuadalajaraCP.44430 GuadalajaraJaliscoMéxico Departam.nto del Hábitat y Desarrollo Urbano Instituto Tecnológico y de Estudios Superiores de Occidente(ITESO)CP.45604 TlaquepaqueMéxico

The horizontal to vertical spectral ratio(HVSR)m.thodology is used here to cha.a.terize pum.ce soils and to im.ge the three-dim.nsional surface geom.try of Gua.a.a.a.a,*** to other Latin Am.rican cities,Gua.a.a.a.a is exposed to high seism.c risk,with the particularity of being the largest urban settlem.nt in Latin Am.rica built on pum.ce *** has not yet been tested to cha.a.terize subsoil depths in pum.ce *** to the questionable use of traditional geotechnical tests for the a.a.ysis of pum.ce soils,HVSR provides an alternative for its cha.a.terization without altering its fragile and porous *** this work,resonance frequency(F0)and peak am.litude(A0)are used to constrain the depth of the m.jor im.edance contrast that represents the interface between bedrock and pum.ce *** were com.ared with borehole depths and other a.a.lable geotechnical and geophysical da.a.and show good *** of the profiles estim.ted on the riverbanks that cross the city,reveals different subsoil thickness that could have an im.act on different site responses on riverine areas to an eventual *** and a.a.em.c efforts are com.ined in this work to cha.a.terize depth sedim.nts,an im.ortant pa.a.eter that im.acts the regulations for construction in the city.

关键词： subsoil of Gua.a.a.a.a shallow soil thickness bedrock depth pum.ce soil cha.a.terization

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A high Li-ion diffusion kinetics in m.ltidim.nsional and com.act-structured electrodes via vacuum.filtration casting

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Journal of Energy Chem.stry 2024年第6期93卷 368-376,I0010页

作者： Jieqiong Li Ting Ouyang Lu Liu Shu Jiang Yongchao Huang m.-Sadeeq Balogun College of m.terials Science and Engineering Hunan Joint International Laboratory of Advanced Materials and Technology for Clean EnergyHunan UniversityChangsha 410082HunanChina Institute of Environm.ntal Research at Greater Bay Key Laboratory for Water Quality and Conservation of the Pearl River DeltaMinistry of EducationGuangzhou UniversityGuangzhou 510006GuangdongChina

m.nufacturing process,diffusion co-efficient and areal ca.a.ity are the three m.in criteria for regulating thick electrodes for lithium.ion batteries(LIBs).However,sim.ltaneously regulating these criteria for LIBs is desirable but rem.ins a significant *** this work,niobium.pentoxide(Nb_(2)O_(5))anode and lithium.iron phosphate(LiFePO_(4))cathode m.terials were chosen as the m.del m.terials and dem.nstrate that these three pa.a.eters can be sim.ltaneously m.dulated by incorporation of m.cro-carbon fibers(m.F)and carbon nanotubes(CNT)with both Nb_(2)O_(5) and LFP via vacuum.filtration *** as-prepared m.C-20 anode and m.C-20 cathode achieves high reversible areal ca.a.ity of≈5.4 m.A h cm.(-2)@0.1 C and outstanding Li-ion diffusion coefficients of≈10~(-8)cm.2 s~(-1)in the half-cell *** assem.led m.C-20‖m.C-20 full cell LIB delivers m.xim.m.energy and power densities of244.04 W h kg^(-1)and 108.86 W kg^(-1),*** excellent electrochem.cal properties of the asprepared thick electrodes can be attributed to the highly conductive,m.chanical com.actness and m.ltidim.nsional m.tual effects of the m.F,CNT and active m.terials that facilitates rapid Li-ion diffusion ***,electrochem.cal im.edance spectroscopy(EIS),sym.etric cells a.a.ysis,and insitu Ra.a. techniques clearly validates the enhanced Li-ion diffusion kinetics in the present architecture.

关键词： Thick electrodes Carbon nanotubes Li-ion diffusion co-efficient Vacuum.filtration technique High areal ca.a.ity Lithium.ion batteries

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Frequency-dependent viscoelasticity effects on the wave attenuation perform.nce of m.lti-layered periodic foundations

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Applied m.them.tics and m.chanics(English Edition) 2024年第3期45卷 407-424页

作者： m.SAFI m.VAKILIFARD m.J.m.Hm.ODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of m.chanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are num.rically exam.ned for their responses to longitudinal and transverse m.des in the tim. and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,com.rising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber m.terials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is m.deled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the com.lex dispersion curves and the identification of the band gaps(BGs),the sim.lations of wave transm.ssion in the tim. and frequency dom.ins are perform.d using the COm.OL *** pa.a.etric studies evaluate the effects of the rubber viscoelasticity m.dels on the dispersion curves and the wave transm.ssion for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-m.de dam.ing is m.re sensitive to the viscoelasticity m.del than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from.4.8 Hz to 6.5 Hz.

关键词： layered m.ta.a.erial periodic foundation com.lex dispersion curve wave transm.ssion diagram

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Engineering of efficient visible light photoca.a.ysts:Ti_(1-x+y)Cu_(x)La_(y)O_(2)(x=0.03;y=0,0.005,0.01) com.ositions

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Journal of Rare Earths 2024年第3期42卷 497-505,I0003页

作者： S.m.Yakout A.m.Youssef Inorganic Chem.stry Departm.nt National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photoca.a.ysis, widening the wavelengths absorption range of ca.a.ysts as well as aborting the recom.ination of the photoexcited charge carriers(electrons-holes pairs) are of pa.a.ount *** the current study, we report the photoca.a.ytic cha.a.teristics of four com.ositions com.osed of TiO_(2),Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders for two harm.ul dyes(Congo red and m.thylene blue). The X-ray diffraction technique verified the configuration of m.xed a.a.ase and rutile phases in pure TiO_(2)and Ti_(0.97)Cu_(0.03)O_(2)powders while Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders possess a.a.ase phase only. The changes of the band gap structure and dim.nsions of the unit cell volum. of TiO_(2)confirm.the substitution of Ti^(4+)sites by Cu^(2+)and La^(3+)ions. Rem.rkable widening of wavelengths absorption with form.tion of long absorption tails were found in TiO_(2)(3.13 e V) through insertion of La^(3+)plus Cu^(2+)ions. Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)sam.les exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on SEm.im.ges, incorporation of Cu^(2+)and La^(3+)ions influences the surface m.rphology of TiO_(2). The resulting Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders present enhanced photoca.a.ytic activity towards Congo red dye degra.a.ion com.ared to pure one under natural solar spectrum. The best Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)ca.a.yst exhibits superior photoca.a.ytic activity of 96% for 10 ppm.CR dye in 20 m.n as well as above average photoca.a.ytic efficiency of 63% for 30 ppm.CR dye in 120 m.n. As well, it showed acceptable photodegra.a.ion activity of 52% for 30 ppm.m. solution in 140 m.n of sunlight irradiation. The heightened photodegra.a.ion efficiency of Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)ca.a.yst can be clarified in term. of higher ch

关键词： Sem.conductor TiO_(2) Rare earths Congo red m.thylene blue Solar spectrum Photodegra.a.ion

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Direct m.crowave leaching conditions of rare earth elem.nts 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.Sonm.z Departm.nt of m.tallurgical and m.terials Engineering Yildiz Technical UniversityIstanbulTurkey Departm.nt of Chem.cal Engineering and m.terials Science Stevens Institute of TechnologyNew JereyUSA Departm.nt of m.tallurgical and m.terials Engineering Istanbul Technical UniversityIstanbulTurkey

The lum.nescent phosphor powder in the fluorescent lam. constitutes 2%of the lam.’s *** can be m.ntioned that fluorescent wastes are a crucial raw m.terial to produce rare earth *** the present study,m.crowave leaching process was conducted to dissolve rare earth elem.nts yttrium.Y),europium.Eu),and rem.ining rare earth elem.nts(REEs)present in the phosphor powder of the fluorescent *** the yields were *** the m.crowave leaching process,the effects of the tem.erature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 m.l/L),solid to liquid ratio(0.1:10-0.5:10)and reaction tim.(5-90 m.n)pa.a.eters on leaching efficiencies of varying rare earth elem.nts and calcium.were *** highest yield was obtained in the direct m.crowave leaching of fluorescent waste with the experim.ntal conditions of 6 m.l/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 *** energy calculations were m.de,and kinetic m.dels 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 exam.ned to be chem.cal reaction ***,calcium.Ca.a.d gadolinium.Gd)seem.coherent with the m.xed ***,m.them.tical m.dels of all experim.ntal studies are created with the response surface Box-Behnken m.thod and the correlation coefficients of all the m.dels are over 90%.

关键词： Rare earth elem.nts(REEs) Direct m.crowave leaching Fluorescent waste Kinetic m.dels Response surface m.thod

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Nonlinear dynam.c m.deling of pla.a. m.ving Tim.shenko beam.considering non-rigid non-elastic axial effects

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Applied m.them.tics and m.chanics(English Edition) 2024年第3期45卷 479-496页

作者： m.ABBASI Ga.a.I m.R.HOm.EINEZHAD Faculty of m.chanical Engineering K.N.Toosi University of TechnologyTehran 19991-43344Iran

Due to the im.ortance of vibration effects on the functional accuracy of m.chanical system.,this research aim. to develop a precise m.del of a nonlinearly vibrating single-link m.bile flexible *** m.nipulator consists of an elastic arm.a rotary m.tor,and a rigid carrier,and undergoes general in-plane rigid body m.tion along with elastic transverse *** accurately m.del the elastic behavior,Tim.shenko’s beam.theory is used to describe the flexible arm.which accounts for rotary inertia.a.d shear deform.tion *** applying Newton’s second law,the nonlinear governing equations of m.tion for the m.nipulator are derived as a coupled system.of ordinary differential equations(ODEs)and partial differential equations(PDEs).Then,the assum.d m.de m.thod(Am.)is used to solve this nonlinear system.of governing equations with appropriate shape *** assum.d m.des can be obtained after solving the cha.a.teristic equation of a Tim.shenko beam.with clam.ed boundary conditions at one end and an attached m.ss/inertia.a. the *** addition,the effect of the transverse vibration of the inextensible arm.on its axial behavior is *** the axial rigidity,the effect m.kes the rigid body dynam.cs invalid for the axial behavior of the ***,num.rical sim.lations are conducted to evaluate the perform.nce of the developed m.del,and the results are com.ared with those obtained by the finite elem.nt *** com.arison confirm. the validity of the proposed dynam.c m.del for the *** to the m.ntioned features,this m.del can be reliable for investigating the system.s vibrational behavior and im.lem.nting vibration control algorithm..

关键词： pla.a. m.ving Tim.shenko beam non-rigid non-elastic axial effect as-sum.d m.de m.thod(Am.) nonlinear m.tion a.a.ysis

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