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Applied m..hem..ics and m..hanics(English Edition) 2024年第3期45卷 407-424页

作者： m..AFI m..AKILIFARD m...m..m..DI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of m..hanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are num..ically exam..ed for their responses to longitudinal and transverse m..es in the tim..and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,com..ising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber m..erials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is m..eled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the com..ex dispersion curves and the identification of the band gaps(BGs),the sim..ations of wave transm..sion in the tim..and frequency dom..ns are perform.. using the COm..L *** param..ric studies evaluate the effects of the rubber viscoelasticity m..els on the dispersion curves and the wave transm..sion for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-m..e dam..ng is m..e sensitive to the viscoelasticity m..el than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from...8 Hz to 6.5 Hz.

关键词： layered m..am..erial periodic foundation com..ex dispersion curve wave transm..sion diagram

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

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

作者： S.m..akout A.m..oussef Inorganic Chem..try Departm..t National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photocatalysis, widening the wavelengths absorption range of catalysts as well as aborting the recom..nation of the photoexcited charge carriers(electrons-holes pairs) are of param..nt *** the current study, we report the photocatalytic characteristics of four com..sitions com..sed 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..l dyes(Congo red and m..hylene blue). The X-ray diffraction technique verified the configuration of m..ed anatase 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 anatase phase only. The changes of the band gap structure and dim..sions of the unit cell volum..of TiO_(2)confirm..he substitution of Ti^(4+)sites by Cu^(2+)and La^(3+)ions. Rem..kable widening of wavelengths absorption with form..ion 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..es exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on SEm..m..es, incorporation of Cu^(2+)and La^(3+)ions influences the surface m..phology 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 photocatalytic activity towards Congo red dye degradation com..red to pure one under natural solar spectrum..The best Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst exhibits superior photocatalytic activity of 96% for 10 ppm..R dye in 20 m.. as well as above average photocatalytic efficiency of 63% for 30 ppm..R dye in 120 m... As well, it showed acceptable photodegradation activity of 52% for 30 ppm..B solution in 140 m.. of sunlight irradiation. The heightened photodegradation efficiency of Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst can be clarified in term..of higher ch

关键词： Sem..onductor TiO_(2) Rare earths Congo red m..hylene blue Solar spectrum Photodegradation

Nonlinear dynam.. m..eling of planar m..ing Tim..henko beam..onsidering non-rigid non-elastic axial effects

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Applied m..hem..ics and m..hanics(English Edition) 2024年第3期45卷 479-496页

作者： m..BBASI GAVARI m...HOm..INEZHAD Faculty of m..hanical Engineering K.N.Toosi University of TechnologyTehran 19991-43344Iran

Due to the im..rtance of vibration effects on the functional accuracy of m..hanical system..this research aim..to develop a precise m..el of a nonlinearly vibrating single-link m..ile flexible *** m..ipulator consists of an elastic arm.. rotary m..or,and a rigid carrier,and undergoes general in-plane rigid body m..ion along with elastic transverse *** accurately m..el the elastic behavior,Tim..henko’s beam..heory is used to describe the flexible arm..hich accounts for rotary inertia and shear deform..ion *** applying Newton’s second law,the nonlinear governing equations of m..ion for the m..ipulator are derived as a coupled system..f ordinary differential equations(ODEs)and partial differential equations(PDEs).Then,the assum.. m..e m..hod(Am..is used to solve this nonlinear system..f governing equations with appropriate shape *** assum.. m..es can be obtained after solving the characteristic equation of a Tim..henko beam..ith clam..d boundary conditions at one end and an attached m..s/inertia at the *** addition,the effect of the transverse vibration of the inextensible arm..n its axial behavior is *** the axial rigidity,the effect m..es the rigid body dynam..s invalid for the axial behavior of the ***,num..ical sim..ations are conducted to evaluate the perform..ce of the developed m..el,and the results are com..red with those obtained by the finite elem..t *** com..rison confirm..the validity of the proposed dynam.. m..el for the *** to the m..tioned features,this m..el can be reliable for investigating the system.. vibrational behavior and im..em..ting vibration control algorithm..

关键词： planar m..ing Tim..henko beam non-rigid non-elastic axial effect as-sum.. m..e m..hod(Am.. nonlinear m..ion analysis

Free vibration and buckling analysis of polym..ic com..site beam..reinforced by functionally graded bam..o fbers

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Applied m..hem..ics and m..hanics(English Edition) 2024年第3期45卷 543-562页

作者： H.m..EIZABAD m...YAS Departm..t of m..hanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcem..t m..erials in polym..s on account of their environm..tal and econom.. advantages in com..rison with synthetic fibers in the recent *** fibers are renowned for their good m..hanical properties,abundance,and short cycle *** beam..are one of the fundam..tal structural com..nents and are susceptible to m..hanical loads in engineering applications,this paper perform..a study on the free vibration and buckling responses of bam..o fiber reinforced com..site(BFRC)beam..on the elastic *** different functionally graded(FG)layouts and a uniform..ne are the considered distributions for unidirectional long bam..o fibers across the *** elastic properties of the com..site are determ..ed with the law of *** Ham..ton’s principle,the governing equations of m..ion are *** generalized differential quadrature m..hod(GDQm..s then applied to the equations to obtain the *** achieved outcom.. exhibit that the natural frequency and buckling load values vary as the fiber volum..fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam..**,a com..rative study is conducted between the derived analysis outcom.. for BFRC and hom..enous polym.. beam..to exam..e the effectiveness of bam..o fibers as reinforcem..t m..erials,dem..strating the significant enhancem..ts in both vibration and buckling responses,with the exception of natural frequencies for cantilever beam..on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beam..are also com..red with those for carbon nanotube reinforced com..site(CNTRC)beam..found in the literature,indicating that the buckling loads and natural frequencies of BFRC beam..are lower than those of CNTRC beam..

关键词： bam..o fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature m..hod(GDQm)

Enhanced quantum..esources via two distant atom..avity system..under the influence of atom.. dissipation

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Com..nications in Theoretical Physics 2024年第2期76卷 62-73页

作者： m..etodeh Kheirabady m.. Tavassoly m..afeie E Ghasem..n Laser and Optics Group Faculty of PhysicsYazd UniversityYazd 89195-741Iran Departm..t of Electrical Engineering Faculty of Intelligent Systems Engineering and Data SciencePersian Gulf UniversityBushehrIran

Quantum..esources such as entanglem..t and coherence are the holy grail for m..ern quantum..echnologies. Although the unwanted environm..tal effects tackle quantum..nform..ion processing tasks, suprisingly these key quantum..esources m.. be protected and even enhanced by the im..em..tation of som..special hybrid open quantum..ystem.. Here, we aim..o show how a dissipative atom..avity-system..an be accom..ished to generate enhanced quantum..** do so, we consider a couple of dissipative cavities, where each one contains two effective two-level atom..interacting with a single-m..e cavity field. In practical applications, a classical laser field m.. be applied to drive each atom.. subsystem..After driving the system..a Bell-state m..surem..t is perform.. on the output of the system..o quantify the entanglem..t and coherence. The obtained results reveal that the rem..e entanglem..t and coherence between the atom..existing inside the two distant cavities are not only enhanced, but can be stabilized, even under the action of dissipation. In contrast, the local entanglem..t between two atom..inside each dissipative cavity attenuates due to the presence of unwanted environm..tal ***, the local coherence m.. show the sam..behavior as the rem..e ***, the system..rovides the steady state entanglem..t in various interaction regim..,particularly in the strong atom..avity coupling and with relatively large detuning. m..e interestingly, our num..ical analyses dem..strate that the system..ay show a m..ory effect due to the fact that the death and revival of the entanglem..t take place during the interaction. Our proposed m..el m.. find potential applications for the im..em..tation of long distance quantum..etworks. In particular, it facilitates the distribution of quantum..esources between the nodes of large-scale quantum..etworks for secure com..nication.

关键词： rem..e entanglem..t and coherence atom.. dissipation steady state entanglem..t Bell-statem..surem..t

Effects of m..tiple shapes for steady flow with transform.. oil+Fe_(3)O_(4)+TiO_(2) between two stretchable rotating disks

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Applied m..hem..ics and m..hanics(English Edition) 2024年第2期45卷 373-388页

作者： m..AHm.. m..URKYILm..OGLU Z.m..HTAQ Departm..t of m..hem..ics Mirpur University of Science and TechnologyMirpur 10250Pakistan Departm..t of m..hem..ics Hacettepe UniversityBeytepeAnkara 06532Turkiye

In this study,we exam..e the effects of various shapes of nanoparticles in a steady flow of hybrid nanofluids between two stretchable rotating *** steady flow of hybrid nanofluids with transform.. oil as the base fluid and Fe_(3)O_(4)+TiO_(2)as the hybrid nanofluid is *** shapes of Fe_(3)O_(4)+TiO_(2)hybrid nanofluids,including sphere,brick,blade,cylinder,and platelet,are *** shape exists in the sam..volum..of a *** leading equations(partial differential equations(PDEs))are transform.. to the nonlinear ordinary differential equations(ODEs)with the help of sim..arity *** system..f equations takes the form..f ODEs depending on the boundary conditions,whose solutions are com..ted num..ically by the bvp4c m..LAB *** outputs are com..red with the previous findings,and an intriguing pattern is discovered,such that the tangential velocity is increased for the rotation param..er,while it is decreased by the stretching values because of the lower *** the reaction rate param..er,the concentration boundary layer becom.. shorter,and the activation energy com..nent increases the rate at which m..s transfers com..to the higher disk but have the opposite effect on the bottom..** ranges of various param..ers taken into account are Pr=6.2,Re=2,m...0,φ_(1)=φ_(2)=0.03,K=0.5,S=-0.1,Br=0.3,Sc=2.0,α_(1)=0.2,γ=0.1,E_(n)=2.0,and q=1.0,and the rotation factor K is within the range of 0 to 1.

关键词： transform.. oil Brinkm.. num..r skin friction coefficient double rotating disk Nusselt num..r Sherwood num..r

Enhancem..t of coercivity,perm..bility,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites for m..ory and high frequency devices

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Journal of Rare Earths 2024年第6期42卷 1128-1135,I0005页

作者： I.Sardar m...Hossain m...Sikder m...I.Khan m...Rahm.. Physics Discipline Khulna UniversityKhulna9208Bangladesh Departm..t of Physics Khulna University of Engineering&TechnologyKhulna9203Bangladesh Departm..t ofCom..ter Science and Engineering Northern University of Business&Technology KhulnaKhulna9100Bangladesh m..erial Science Division Atomic Energy CentreDhaka1000Bangladesh

Spinel cubic ferrites have huge applications in m..m..y and high frequency *** the im..ovem..t of these m..ern devices,the m..netic coercivity,perm..bility,and dielectric properties of a ferrite are the im..rtant *** article focuses on im..oving the m..netic coercivity,m..netic perm..bility,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and *** X-ray diffraction(XRD),Fourier transform..nfrared spectroscopy(FTIR),field em..sion scanning electron m..roscopy(FESEm..energy dispersive X-ray(EDX),vibrating sam..e m..netom..er(VSm..and an im..dance analyzer were used to characterize the structural,m..netic,and dielectric properties of the *** XRD patterns indicate the form..ion of spinel cubic structure of the sam..es with a secondary peak(EuFeO_(3))for Eu doped *** densities and porosities of the sam..es follow an inverse trend,where the doped sam..es’lattice param..ers are increased with the increm..t of rare earth Eu *** FTIR analysis also proves the spinel cubic phase of the *** average grain size of the ferrites is obtained via FESEm..m..es,and it is increased from..21 to 198 *** analysis confirm..that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ***,the coercivity of the Eu doped sam..es is greater than that of the m..her alloy(x=0.00).The EDX study shows that there is no im..rity contam..ation in the *** perm..bility and dielectric m..surem..ts show an im..oved quality factor of the Eu-doped sam..es with low m..netic and dielectric *** dependent resistivity and im..dance analysis also show the im..oved *** the observed properties of the sam..es,all the investigated ferrites m..ht be strong candidates for potential applications in m..ory devices,m..netic sensors,and high frequency applications.

关键词： Ferrites Raree arths Coercivity Perm..bility EDX Resistivity

Facile synthesis of sam..ium..nd cerium..oped double perovskite cobaltite with enhanced dielectric response

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

作者： Yasir Abbas m..am..n m..nis-ur-Rehm.. Applied Therm.. Physics Laboratory Department of PhysicsCOMSATS University IslamabadIslamabad 45550Pakistan

The investigation of Sm..e 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..s were synthesized by a facile synthesis technique nam.. the co-precipitation route.X-ray diffraction(XRD)reveals that BCSCCO crystallizes into one phase with space group P21/*** crystallite size,dislocation density,lattice param..ers,lattice strain,unit cell volum..and bulk density were determ..ed using XRD *** structural properties of Bi_(2)Ca_(2)CoO_(6)were exam..ed using calculations based on the density functional *** and experim..tal values discrepancy is less than 1%.A scanning electron m..roscope was used for perform..g a m..rostructural *** SEm..m..es dem..strate the hom..eneous distribution of grains with a range of sizes(0.054-0.090μm..The alternating current(ac)conductivity,dielectric perm..tivity,and tangent loss were also studied as a function of frequency(20 Hz-3 m..)at different tem..ratures(100-500℃).All synthesized sam..es were exam..ed using non-linear Debye's function to determ..e their spreading factor and relaxation *** specim.. with the lowest crystallite size(∼23 nm..xhibits a high dielectric perm..tivity(∼3.80×10^(6)).The conduction m..hanism..as exam..ed in the studied sam..es 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..sitions follow non-overlapping polaron *** studied specim.. 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..s m..e from..alcium..obaltite using solid-state reactions(5.0-26.0 S/cm..

关键词： Bism..h calcium..am..ium..erium..obaltite (BCSCCO) Spreading factor Conduction m..hanism Rare earths

Braneworld black holes with m..m.. electrodynam..s on the brane

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Com..nications in Theoretical Physics 2024年第6期76卷 120-128页

作者： Haryanto m..iahaan Jurusan Fisika Universitas Katolik ParahyanganJalan Ciumbuleuit 94Bandung 40141Indonesia

In this study,we investigate m..m.. electrodynam..s localized within the Randall-Sundrum.. and Dvali-Gabadadze-Porrati branes,deriving corresponding 3-brane spacetim..solutions that conform..o the effective Einstein equations in each specific *** construct solutions for charged black holes within the effective Einstein equation fram..ork in both braneworld *** exam..ation explores the trajectories of charged objects in this spacetim..underscoring the significance of the nonlinear *** analysis uncovers the fact that,sim..ar to the prior m..m.. black hole investigation,the nonlinear param..er plays a pivotal role in suppressing the effective charge of the black hole,due to its definite positive value.

关键词： RS-II DGP m..m.. brane

Higgs-like(pseudo)scalars in AdS_(4),m..ginal and irrelevant deform..ions in CFT_(3),and instantons on S^(3)

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Chinese Physics C 2024年第4期48卷 68-81页

作者： m..aghdi Departm..t of Physics Faculty of Basic SciencesUniversity of IlamIlamIran

Em..oying a 4-form..nsatz of 11-dim..sional supergravity over a non-dynam..al AdS_(4)×S^(7)/Z_(k)background and setting the internal space as an S1 Hopf fibration on CP3,we obtain a consistent ***(pseudo)scalars,in the resulting scalar equations in Euclidean AdS_(4)space,m.. be considered to arise from..nti)m..ranes wrapping around the internal directions in the(Wick-rotated)skew-whiffed m..brane background(as the resulting theory is for anti-m..branes),thus realizing the m..es after swapping the three fundam..tal representations 8_(s),8_(c),and 8_(v) of SO(8).Taking the backreaction on the external and internal spaces,we obtain the m..sless and m..sive m..es,corresponding to exactly m..ginal and m..ginally irrelevant deform..ions on the boundary CFT3,***,we obtain a closed solution for the bulk equation and com..te its correction with respect to the background ***,considering the Higgs-like(breathing)m..e m..2)=18,having all supersym..tries as well as parity and scale-invariance broken,solving the associated bulk equation with m..hem..ical m..hods,specifically the Adom..n decom..sition m..hod,and analyzing the behavior near the boundary of the solutions,we realize the boundary duals in the SU(4)×U(1)-singlet sectors of the ABJm..**,introducing the new dual deform..ionΔ_(+)=3,6 operators m..e of bi-fundam..tal scalars,ferm..ns,and U(1)gauge fields,we obtain the SO(4)-invariant solutions as sm..l instantons on a three-sphere with the radius at infinity,which correspond to collapsing bulk bubbles leading to big-crunch singularities.

关键词： AdS_(4)/CFT_(3)correspondence scalar equations in AdS_(4) instantons m..ginal and irrelevant operators (anti)m..ranes