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Structural and superconducting properties in Y_(0.6)Gd_(0.4)Ba_2(Nb)Cu_3O_(7-y) cuprates doped with niobium

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Journal of Rare Earths 2012年第3期30卷 241-244页

作者： m. yilmaz O. Dogan A. K. Education Faculty Department of Physics Konya University

Polycrystalline YBa2Cu3O7-y （YBCO） and Y0.6Gd0.4Ba2-xNbxCu3O7-y （YGBNCO） com.ounds with 0≤x≤0.225 were synthesized using standard solid state reaction technique. The structure for all sam.les was characterized by X-ray difference （XRD） and scanning electron m.croscopy （SEm.. The transport properties were m.asured by the （FPP） m.thod in the tem.erature range from.70 to 130 K. As the Nb content in the sam.les increased, a diffused phase indicating a niobium.perovskite phase and a sm.ll am.unt of unidentified phase appeared. With the increase of Nb content, the superconducting transition tem.erature Tconset increased slowly with x≤0.125, and then it rem.ined unchanged or slowly decreased with 0.125≤x≤0.225. It could be found that there was a slow decrease of zero-resistance tem.erature, Tcoffset, with the increase of Nb content. The larger transition width m.ght result from.the YBa2NbO6 phase, im.urity and unidentified phases of the sam.le due to the Nb doping.

关键词： Y0.6Gd0.4Ba2Cu3O7-y cuprates Gd and Nb co-doping structural and superconducting properties rare earths

Investigation of electron beam.effects on L-shell m. plasm. produced by a com.act LC generator using pattern recognition

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m.tter and Radiation at Extrem.s 2019年第2期4卷 52-58页

作者： m.F.yilmaz Y.Danism.n m.Ozdem.r B.Karlık J.Larour Basic Sciences Engineering DepartmentImam Abdulrahman Bin Faisal UniversityDammamSaudi Arabia Departm.nt of m.them.tics and Com.uter Sciences Queensborough Community CollegeCUNYBaysideNew York 11364USA Neurosurgical Sim.lation Research and Training Centre Department of NeurosurgeryMontreal Neurological Institute and HospitalMcGill UniversityMontrealQuebec H3A 2B4Canada Laboratoire de Physique des Plasm.s(LPP) Ecole PolytechniqueUPMCCNRSPalaiseauFrance

In this paper,the effects of an electron beam.on X-pinch-produced spectra of L-shellm.plasm. are investigated for the first tim. by principal com.onent analysis(PCA);this analysis is com.ared with that of line ratio diagnostics.A spectral database for PCA extraction is arranged using a non-Local Therm.dynam.c Equilibrium.non-LTE)collisional radiative L-shell m. *** vector spectra of L-shell m.,including F,Ne,Na and m.-like transitions are studied to investigate the polarization types of these ***1 vector spectra of F,Ne,Na and m.-like transitions result in linear polarization of Stokes Q ***,PC2 vector spectra show linear polarization of Stokes U profiles of 2p^(5)3s of Ne-like transitions which are known as responsive to a m.gnetic field[Trabert,Beiersdorfer,and Crespo Lo´pez-Urrutia,*** ***.,Sect.B 408,107–109(2017)].A 3D representation of PCA coefficients dem.nstrates that addition of an electron beam.to the non-LTE m.del generates quantized,collective clusters which are translations of each other that follow V-shaped cascade trajectories,except for the case f=*** extracted principal coefficients are used as a database for an Artificial Neural Network(ANN)to estim.te the plasm. electron tem.erature,density and beam.fractions of the tim.-integrated,spatially resolved L-shellm.X-pinch plasm. ***-based ANNs provide an advantage in reducing the network topology,with a m.re efficient backpropagation supervised learning *** m.deled plasm. electron tem.erature is about Te;660 eV and density n_(e)=1×10^(20) cm.(-3),in the presence of the fraction of the beam. with f-0.1 and centered energy of 5 keV.

关键词： spectrum. beam transitions

m.crostructural evolution and strengthening m.chanism.of aligned steel fiber cem.nt-based tail backfills exposed to electrom.gnetic induction

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International Journal of m.nerals,m.tallurgy and m.terials 2024年第11期31卷 2390-2403页

作者： Xihao Li Shuai Cao Erol yilmaz School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of High-Efficient m.ning and Safety of m.tal m.nes of m.nistry of Education University of Science and Technology BeijingBeijing 100083China Departm.nt of Civil Engineering Geotechnical DivisionRecep Tayyip Erdogan UniversityFener Rize TR53100Turkey

Cem.nted tailings backfill(CTB)not only boosts m.ning safety and cuts surface environm.ntal pollution but also recovers ores previously retained as pillars,thereby im.roving resource *** use of alternative reinforcing products,such as steel fiber(SF),has continuously strengthened CTB into *** approach prevents strength decreases over tim. and reinforces its long-term.durability,especially when m.ning ore in adjacent underground *** this study,various m.crostructure and strength tests were perform.d on SFCTB,considering steel fiber ratio and electrom.gnetic induction strength *** findings show that com.ining steel fibers and their distribution dom.nantly influences the im.rovem.nt of the fill’s ***’s strength rises by fiber insertion and has an evident correlation with fiber insertion and m.gnetic induction *** m.gnetic induction strength is 3×10^(-4) T,peak uniaxial com.ressive stress reaches 5.73 m.a for a fiber ratio of 2.0vol%.The cracks’expansion m.inly started from.the specim.n’s upper part,which steadily expanded downward by increasing the load until dam.ge *** doping of steel fiber and its directional distribution delayed crack *** the doping of steel fiber was 2.0vol%,SFCTBs showed excellent ductility *** energy required for fills to reach destruction increases when steel-fiber insertion and m.gnetic induction strength *** study provides notional references for steel fibers as underground filling additives to enhance the fill’s durability in the course of m.ning operations.

关键词： electrom.gnetic induction steel fiber cem.nted tailings backfill strength m.crostructure

Reinforcing effects of polypropylene on energy absorption and fracturing of cem.nt-based tailings backfill under im.act loading

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International Journal of m.nerals,m.tallurgy and m.terials 2024年第4期31卷 650-664页

作者： Jiajian Li Shuai Cao Erol yilmaz School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of High-Efficient m.ning and Safety of m.tal m.nes of m.nistry of Education University of Science and Technology BeijingBeijing 100083China Departm.nt of Civil Engineering Geotechnical DivisionRecep Tayyip Erdogan UniversityFenerRize TR53100Turkey

Polypropylene(PP)fiber-reinforced cem.nt-based tailings backfill(FRCTB)is a green com.ound m.terial with superior crack resistance and has good prospects for application in underground ***,FRCTB exhibits susceptibility to dynam.c events,such as im.act ground pressure and blast *** paper investigates the energy and crack distribution behavior of FRCTB under dynam.c im.act,considering the height/diam.ter(H/D)*** Hopkinson pressure bar,industrial com.uted tom.graphy scan,and scanning electron m.croscopy(SEm.experim.nts were carried out on six types of *** outcom.s confirm.d fiber aggregation at the bottom.of *** H/D was less than 0.8,the proportion of PP fibers distributed along theθangle direction of80°-90°*** the total energy,all sam.les presented sim.lar energy absorption,reflectance,and ***,a rise in H/D m.y cause a rise in the energy absorption rate of FRCTB during the peak phase.A positive correlation existed between the average strain rate and absorbed energy per unit *** increase in H/D resulted in a decreased crack volum. fraction of *** the H/D was greater than or equal to 0.7,the m.xim.m.crack volum. fraction of FRCTB was observed close to the incidence *** cracks were present only in the FRCTB with an H/D ratio of *** with H/D ratios of 0.5 and 0.6 showed sim.lar distributions of weakly and heavily dam.ged *** fibers can lim.t the em.rgence and expansion of cracks by influencing their *** observations revealed considerable differences in the bonding strengths between fibers and the *** that adhered particularly well to the substrate were attracted together with the hydration products adhering to *** results show that FRCTB is prom.sing as a sustainable and green backfill for determ.ning the design properties of m.ning with backfill.

关键词： cem.nt-based tailings fiber-reinforced backfills fracture energy absorption im.act loading

Experim.ntal study on the effect of m.cro-carbon additives in vegetable oils for aquifer therm.l energy storage

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Clean Energy 2024年第2期8卷 48-59页

作者： Takashi Suzuki m.tsuhisa Ichiyanagi Em.r yilmaz Archie G.K.m.xwell Ekadewi Anggraini Handoyo Departm.nt of Engineering and Applied Sciences Sophia University7-1Kioi-choChiyoda-kuTokyo102-8554Japan Graduate School of Science and Technology Sophia University7-1Kioi-choChiyoda-kuTokyo102-8554Japan Departm.nt of m.chanical Engineering Petra Christian UniversitySiwalankerto 121-131Surabaya 60291Indonesia

Aquifer therm.l energy storage is a versatile m.thod for regulating building tem.eratures,utilizing groundwater as a m.dium.for both sum.er cooling and winter *** has high therm.l conductivity and specific heat but is corrosive,creating a m.neral build-up that causes ***,its high freezing point presents operational *** oils em.rge as a prom.ising alternative,owing to their lower freezing *** light of environm.ntal concerns,researchers are exploring vegetable oils as substitutes for petroleum.derived m.neral *** paper is intended as an initial study using vegetable oils,*** and sunflower oil,as the heat-transfer m.dium.in aquifer therm.l energy *** experim.nts assess the heat-transfer coefficient of coconut,sunflower,m.neral,and synthetic oils when exposed to the sam. heat *** study also evaluates the im.act of introducing m.cro-carbon(graphite and charcoal)to the *** indicate that sunflower oil has the highest heat-transfer coefficient of 374.4 W/m.(2) K am.ng the oils,m.king it suitable for aquifer therm.l energy storage ***,augm.nting sunflower oil with charcoal powder enhances its perform.nce by increasing the heat-transfer coefficient to 474.9 W/m.(2) K,or a 27%*** contrast,coconut oil proves unsuitable for aquifer therm.l energy storage deploym.nt because of its low heat-transfer coefficient of 293.7 W/m.(2) *** heat-transfer coefficient of synthetic oil increases with graphite powder but decreases with charcoal powder introduction.

关键词： sunflower oil aquifer therm.l energy storage charcoal graphite vegetable oil

Facile synthesis of sam.rium.and cerium.doped 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.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 param.ters,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 relaxation *** 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.sam.rium.cerium.cobaltite (BCSCCO) Spreading factor Conduction m.chanism Rare earths

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 guarantee 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

HVSR analysis of pum.ce sands for sedim.nt depth characterization:A case study for Guadalajara,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 characterize pum.ce soils and to im.ge the three-dim.nsional surface geom.try of Guadalajara,*** to other Latin Am.rican cities,Guadalajara 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 characterize subsoil depths in pum.ce *** to the questionable use of traditional geotechnical tests for the analysis of pum.ce soils,HVSR provides an alternative for its characterization 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 available geotechnical and geophysical data 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 academ.c efforts are com.ined in this work to characterize depth sedim.nts,an im.ortant param.ter that im.acts the regulations for construction in the city.

关键词： subsoil of Guadalajara shallow soil thickness bedrock depth pum.ce soil characterization

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 capacity 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 param.ters 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 capacity 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 analysis,and insitu Ram.n 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 capacity Lithium.ion batteries