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

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

作者： Ram A.Pawar Sunil m.Patange P.m.Dighe Sher Singh meena Abdullah GAl-Sehemi mehboobali Pannipara Santosh S.Jadhav Department of Physics ArtsCommerce and Science CollegeAhmednagar413711MaharashtraIndia Department of Physics Shri Krishna MahavidyalayaGunjotiDistOsmanabad413606MaharashtraIndia Padmashri Vikhe Patil College of Arts Science and CommercePravaranagarA/P.Loni(Kd)Tal.RahataDistAhmednagar413713MaharashtraIndia Solid State Physics Division Bhabha Atomic Research CentreMumbai400085MaharashtraIndia Department of Chemistry King Khalid UniversityAbha61413Saudi Arabia Department of Physics D.S.M's ArtsCommerce and Science CollegeJintur431509MaharashtraIndia

The present study is a systematic effort to investigate the structure-sensitive magnetic parameters of Ce^(3+) substituted Ba-Sr hexaferrite nanocrystals chemically formulated 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 characterized by means of powder X-ray diffraction and Fourier transform infrared *** creation of the m-type hexaferrite phase within the synthesized samples was revealed from the Rietveld refinement 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 data were utilized to compute the lattice parameters,X-ray density,and lattice parameter *** crystal structure plotted from the refined XRD data reveals the occupancy of the ions at different lattice *** XPS data of the hexaferrite were analyzed to confirm the oxidation states of the constituent *** nanocrystalline nature of the hexaferrites was revealed from the crystallite sizes calculated using Scherer's *** analysis of FTIR spectra confirms that only a fraction of Ce^(3+)accommodated in the lattice and the remaining Ce content reside in the form of the CeO_(2) *** morphology of the hexaferrites was analyzed from the FESEm profiles of the ferrite *** magnetic behavior study was performed by analyzing the Curie temperature,hysteresis loops,and hyperfine interactions by means of susceptibility,V.S.m,and mossbauer spectroscopy,*** hexaferrites with increasing coercivity,decreasing saturation magnetization,and decreasing Curie temperature are reported in the *** substituted Ce^(3+)ions inhibit the grain growth and create lattice imperfections giving rise to hexaferrites with tuned magnetic parameters suitable for different applications.

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

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Damage Identification of A TLP Floating Wind Turbine by meta-Heuristic Algorithms

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China Ocean Engineering 2015年第6期29卷 891-902页

作者： m.m.Ettefagh mechanical Engineering Department University of Tabriz

Damage identification of the offshore floating wind turbine by vibration/dynamic signals is one of the important and new research fields in the Structural Health monitoring（SHm）. In this paper a new damage identification method is proposed based on meta-heuristic algorithms using the dynamic response of the TLP（Tension-Leg Platform） floating wind turbine structure. The Genetic Algorithms（GA）, Artificial Immune System（AIS）, Particle Swarm Optimization（PSO）, and Artificial Bee Colony（ABC） are chosen for minimizing the object function, defined properly for damage identification purpose. In addition to studying the capability of mentioned algorithms in correctly identifying the damage, the effect of the response type on the results of identification is studied. Also, the results of proposed damage identification are investigated with considering possible uncertainties of the structure. Finally, for evaluating the proposed method in real condition, a 1/100 scaled experimental setup of TLP Floating Wind Turbine（TLPFWT） is provided in a laboratory scale and the proposed damage identification method is applied to the scaled turbine.

关键词： floating wind turbine multi-body dynamics damage identification meta-heuristic algorithms optimization

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Approximate solutions for the problem of liquid film flow over an unsteady stretching sheet with thermal radiation and magnetic field

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Applied mathematics and mechanics(English Edition) 2018年第6期39卷 867-876页

作者： m.m.KHADER Department of mathematics and Statistics College of ScienceAl-Imam Mohammad Ibn Saud Islamic University(IMSIU) Department of mathematics Faculty of ScienceBenha University

The proposed method is based on replacement of the unknown function by a truncated series of the shifted Legendre polynomial expansion. An approximate formula of the integer derivative is introduced. Special attention is given to study the convergence analysis and derive an upper bound of the error for the presented approximate formula. The introduced method converts the proposed equation by means of collocation points to a system of algebraic equations with shifted Legendre coefficients. Thus, after solving this system of equations, the shifted Legendre coefficients are obtained. This efficient numerical method is used to solve the system of ordinary differential equations which describe the thin film flow and heat transfer with the effects of the thermal radiation, magnetic field, and slip velocity.

关键词： liquid film thermal radiation unsteady stretching sheet Legendrecollocation method convergence analysis

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mssbauer and electron microscopy study of martensitic transformations in an Fe-mn-mo alloy

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International Journal of minerals,metallurgy and materials 2010年第4期17卷 448-452页

作者： T.Kirindi U.Sari m.Kurt Department of Computer Education and Instructional Technology Kirkkale University Kirkkale 71450Turkey Institute of Sciences Kirkkale University Yahsihan CampusKirkkale 71450Turkey

The kinetic,morphological,crystallographic,and magnetic characteristics of thermally induced martensites in Fe-13.4wt% mn-5.2wt%mo alloy were investigated by scanning electron microscopy（SEm）,transmission electron microscopy（TEm）,and m（o｜¨）ssbauer *** experimental results reveal that two types of thermal-induced martensites,e（hcp） andα＇（bcc） martensites,are formed in the as-quenched condition,and these transformations have athermal *** addition to the Fe-mn alloy does not change the coexistence ofεandα＇ martensites with the mn content between 10wt%and 15wt%.Besides,m（o｜¨）ssbauer spectra reveal a paramagnetic character with a singlet for theγ（fcc） austenite andεmartensite phases and a ferromagnetic character with a broad sextet for theα＇ martensite phase. The volume fraction ofα＇ martensite forming in the quenched alloy is much more than that of theεmartensite.

关键词： Fe-mn alloy molybdenum martensitic transformation scanning electron microscopy(SEm) transmission electron microscopy(TEm) mossbauer spectroscopy

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Optimizing the Preparation Parameters of Nanocrystalline Zirconia for Catalytic Applications

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Acta metallurgica Sinica(English Letters) 2013年第5期26卷 565-573页

作者： m.m.Abd El-Latif m.S.Showman A.m.Ibrahim m.m.Soliman Fabrication Technology Department Advanced Technology and New Materials Research Institute(ATNMRI) City of Scientific Research and Technological Applications (SRTA-City) Dharyya Colleges for Science and Atrs Qassim University Surface Chemistry and Catalysis Laboratory Physical Chemistry Department National Research Center Department of materials Science Institute of Graduate Studies and Research Alexandria University

Nanocrystalline zirconia powder with high surface area and high tetragonal phase percentage is prepared by the precipitation method using ammonium hydroxide as a precipitating agent. The pH of precipitation, preparation temperature and calcinations＇ temperature are *** size, specific surface area, tetragonal phase percentage and the thermal stability of the prepared samples are identified by diferent characterization tools such as X-ray difraction（XRD）, thermo gravimetric analysis（TGA）, diferential scanning calorimetry（DSC）, BET surface area, scanning electron microscopy（SEm） and transmission electron microscopy（TEm）. The optimum preparation parameters for obtaining nanocrystalline zirconia with high percentage of tetragonal phase and high surface area are pH 9, preparation temperature of 80℃ and calcinations＇ temperature of 400℃. The sample prepared under optimized conditions showed a high specific surface area of 179.2 m2/g, high tetragonal phase percentage of 81% and high catalytic activity（60%） for synthesis of butyl acetate ester.

关键词： Tetragonal zirconia Nanocrystalline zirconia Precipitation synthesis Catalytic properties of zirconia Esterification with zirconia

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Dissipative dynamics of an entangled three-qubit system via non-Hermitian Hamiltonian: Its correspondence with markovian and non-markovian regimes

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Chinese Physics B 2021年第3期30卷 283-292页

作者： m Rastegarzadeh m K Tavassoly Laser and Optics Group Faculty of PhysicsYazd UniversityYazd 89195-741Iran

We investigate an entangled three-qubit system in which only one of the qubits experiences the decoherence effect by considering a non-Hermitian Hamiltonian,while the other two qubits are isolated,i.e.,do not interact with environment,***,the time evolution of the density matrix(for the pure as well as mixed initial density matrix)and the corresponding reduced density matrices are obtained,by which we are able to utilize the dissipative non-Hermitian Hamiltonian model with markovian and non-markovian regimes via adjusting the strange of the non-Hermitian term of the total Hamiltonian of the under-considered system.

关键词： non-Hermitian Hamiltonian entanglement concurrence measure markovian and non-markovian regimes

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Dynamic simulation of beam-like structure with a crack subjected to a random moving mass oscillator

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Earthquake Engineering and Engineering Vibration 2009年第3期8卷 447-458页

作者： m.m.Ettefagh m.H.Sadeghi m.Rezaee Vibration and modal Analysis Laboratory 51666-14766Department of Mechanical EngineeringUniversity of TabrizTabrizIran

In this paper, dynamic simulation of a beam-like structure with a transverse open crack subjected to a random moving mass oscillator is investigated. The simultaneous effect of a crack and a random oscillator has not been addressed up to now. The crack in the beam at different locations and with different depths is considered as one group of damage, each as an individual imperfection. In addition, bearing immobility is considered as another type of problem in the beam. mass, stiffness, damping and velocity of the oscillator are assumed to be random parameters. An improved perturbation technique is applied to reduce the simulation time. It was found that there is a maximum value of the variance of each uncertain parameter, in which the maximum reliability of the perturbation method can be achieved, and that this maximum value can be obtained by the Alpha-Hilber monte-Carlo simulation method. The simulation results reveal that the mass and the velocity uncertainty cause high uncertainty in the deflection of the beam. Also, the pattern of the deflection is not affected by different random oscillator parameters, and as a result, the type of damage can be identified even with high uncertainty. moreover, the deflection in the nodes around the mid-span of the beam provides the best information regarding the imperfections, and consequently leads to the best sensor locations in an actual experiment.

关键词： bridge-vehicle interaction moving mass oscillator random parameters monte-Carlo simulation perturbation method

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Cracking in orthotropic half-plane with a functionally graded coating under anti-plane loading

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Acta mechanica Solida Sinica 2015年第2期28卷 210-220页

作者： m. m. monfared m. Ayatollahi Faculty of Engineering University of Zanjan

This investigation evaluates, by the dislocation method, the dynamic stress intensity factors of cracked orthotropic half-plane and functionally graded material coating of a coating- substrate material due to the action of anti-plane traction on the crack surfaces. First, by using the complex Fourier transform, the dislocation problem can be solved and the stress fields are obtained with Cauchy singularity at the location of dislocation. The dislocation solution is utilized to derive integral equations for multiple interacting cracks in the orthotropic half-plane with functionally graded orthotropic coating. Several examples are solved and dynamic stress intensity factors are obtained.

关键词： orthotropic half-plane multiple cracks functionally graded coating

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SWELLING BEHAVIOR OF ACRYLAmIDE HYDROGEL IN DIFFERENT SOLVENTS AND pHs

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Chinese Journal of Polymer Science 2005年第3期23卷 269-274页

作者： m.F.mina m.m.Alam Institute of Nuclear Science and Technology Atomic Energy Research EstablishmentGPO Box-3787Dhaka-1000BangladeshInstitute of Nuclear Science and TechnologyAtomic Energy Research EstablishmentGPO Box-3787Dhaka-1000Bangladesh

Swelling property of acrylamide hydrogels,prepared from aqueous solutions of acrylamide monomer havingconcentrations in the range of 10-60 wt% by ray irradiation method using a Co-60 gamma radiation source at dosesranging 1-30.0 kGy,has been investigated under various swelling *** swelling media were basically solvents(solutions),produced by dissolving methanol,ethanol,glucose,sucrose,sodium chloride and sodium persulfate individuallywith distilled water,and solutions prepared with pHs=3,7 and *** investigation was performed in order to observe theeffect of these solvents and pHs as well as the influence of monomer concentrations,radiation doses and times on swellingbehavior of *** values were found higher for hydrogels prepared with lower monomer concentrations(ca.20 wt%)and radiation doses(ca.5 kGy)and showed a leveling off tendency within 24 *** glucose solvent and the buffersolution of pH=10 revealed significant increase of swelling of hydrogels as compared to other *** areexplained based on crosslinking density in hydrogel,polymer-solvent/polymer-polymer interactions in solutions,permeability of molecules in solutions and ionization capacity of hydrogel in pH.

关键词： Acrylamide Hydrogel Co-60 gamma radiation source Swelling.

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Plasma Treatment of Natural Jute Fibre by RIE 80 plus Plasma Tool

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Plasma Science and Technology 2010年第3期12卷 325-329页

作者： m.m.mORSHED m.m.ALAm S.m.DANIELS National Centre for Plasma Science and Technology Dublin City University Nanomaterials Processing Laboratory School of Electronic EngineeringDublin City University

Plasma treatment can be used to modify the structure of natural fibre like jute for a variety of applications. Environmentally friendly jute fibre was treated with argon and oxygen plasma. The treated samples were characterized by X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR） and optical microscope. The macromolecular and microstructural changes in cellulose confirmed the change by plasma treatment. The XRD results confirmed that the crystal size and the crystallinity of the plasma treated fibre increased. Argon plasma treated fibre had a smooth and compact surface, compared to oxygen plasma treated fibre. The maximum stain （i.e. stress） concentrated in the oxygen plasma treated fibre. Optical micrographs showed the oxygen plasma treated fibre tended to rupture due to higher strain （i.e., stress） compared to fibre with argon plasma treatment. FTIR results also provided the evidence of change in the chemical constituents with plasma treatment.

关键词： natural jute fibre plasma treatment crystallinity chemical composition

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