A5044997056- Magnetic Properties of Alloys
- Magnetic and transport properties of perovskites and related materials
- Shape Memory Alloy Transformations
- Metallic Glasses and Amorphous Alloys
- Rare-earth and actinide compounds
- Magnetic properties of thin films
- Magnetic Properties and Applications
- Advanced Condensed Matter Physics
- ZnO doping and properties
- Heusler alloys: electronic and magnetic properties
- Phase-change materials and chalcogenides
- High Entropy Alloys Studies
- Thermal Expansion and Ionic Conductivity
- Theoretical and Computational Physics
- Multiferroics and related materials
- Advanced Thermodynamics and Statistical Mechanics
- Heat Transfer and Optimization
- Physics of Superconductivity and Magnetism
- Ferroelectric and Piezoelectric Materials
- Creativity in Education and Neuroscience
- Superconducting Materials and Applications
- Magnetic and Electromagnetic Effects
- Perovskite Materials and Applications
- Intermetallics and Advanced Alloy Properties
- Lattice Boltzmann Simulation Studies
Vietnam Academy of Science and Technology
2015-2024
Institute of Materials Science
2007-2023
Chungbuk National University
2012-2013
University of South Florida
2012
Pohang University of Science and Technology
2004
Centre National de la Recherche Scientifique
2004
Institute of Mathematics
2001-2002
Duke University
1996-1999
University of Bucharest
1995
Universitatea Națională de Știință și Tehnologie Politehnica București
1995
A systematic study of the conventional and inverse magnetocaloric effects critical behaviors in Ni50Mn50−xSnx (x = 13 14) alloy ribbons has been performed. We show that although magnetic entropy change around second-order ferromagnetic-paramagnetic (FM-PM) transition (ΔSm ≈ −4 J/kg K) austenitic phase is about five times smaller than first-order martensitic-austenitic (M-A) transformation 22 K), refrigerant capacity (RC) – an important figure merit two larger for former case (RC 160 J/kg)...
We have studied Raman scattering in Co-doped ZnO nanorods prepared by thermal diffusion. Experimental results show that the features of their non-resonant spectra are similar to from materials investigated previously. Under resonant conditions, however, there is a strong enhancement multiple-phonon processes. Longitudinal optical (LO)-phonon overtones up eleventh order observed. The modes become more obvious when Co concentration diffused into goes an appropriate value. This phenomenon...
This paper extends to the field of convective heat transfer constructal theory optimizing access a current that flows between one point and finite-size volume, when volume size is constrained. The bathed by uniform stream. A small amount high-conductivity fin material distributed optimally through makes connection (fin root) on its boundary. optimization proceeds in series subsystems increasing sizes (elemental first construct, second construct). shape relative thicknesses fins are optimized...
This paper shows that the time needed to discharge a volume concentrated sink can be minimized by making appropriate changes in geometry of flow path. The time-dependent heat between and one point is chosen for illustration, however, same geometric optimization method (the constructal principle) holds other transport processes (fluid flow, mass transfer, conduction electricity). There are two classes degrees freedom designing path: external shape volume, distribution (amount, location,...
The controlled nanocrystallization of as-milled glassy ${\mathrm{Pr}}_{40}{\mathrm{Fe}}_{30}{\mathrm{Co}}_{15}{\mathrm{Al}}_{10}{\mathrm{B}}_{5}$ leads to a Curie temperature $625\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, magnetic remanence ratio 0.55, and very high coercivity $29\phantom{\rule{0.3em}{0ex}}\mathrm{kOe}$, after annealing at $800\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$. X-ray diffraction, high-resolution transmission electron microscopy, magnetization measurements,...
This work presents a detailed study on the critical behavior of ferromagnetic-paramagnetic (FM-PM) phase transition in Fe90−xNixZr10 (x = 0 and 5) alloy ribbons. Basing field dependences magnetization (M-H), M2 versus H/M plots prove alloys exhibiting second-order magnetic transition. To investigate nature FM-PM at TC 245 306 K for x 5, respectively, we performed critical-exponent study. The values components β, γ, δ determined by using modified Arrott plots, Kouvel-Fisher (KF), isotherm...
This paper shows that the geometry of heat flow path between a volume and one point can be optimized in two fundamentally different ways. In “growth” method original constructal theory structure is starting from smallest element fixed size. Growth, or optimal numbers constituents assembled into larger volumes, route to resistance minimization. “design” overall fixed, designer works “inward” by optimizing internal features path. The design new. It shown analytically methods produce comparable...
We report a comparative study of the universal behaviors conventional and inverse magnetocaloric effects (CMCE IMCE, respectively) that coexist in Heusler alloys Ni50Mn50−xSnx (x ∼ 13, 14) Ni50−xPrxMn37Sn13 1, 3). In contrast to CMCE associated with first-order phase transition (FOPT), we show it is possible construct master curve describe temperature dependence magnetic entropy change ΔSM(T) different applied fields without rescaling axis for IMCE FOPT. This behavior shown be from observed...
We report magnetic properties and magnetocaloric (MC) effect in Fe90−xNixZr10 (x = 0, 5, 10, 15) alloy ribbons prepared by rapid-quenching method. found the Curie temperature (TC) of depends strongly on Ni-doping concentration (x) increasing from 245 K for 0), through 306 (for x 5) up to TC 403 15). Also, dependence maximum entropy change (|ΔSmax|) Ni content was readily apparent. Indeed, 0 5 samples that have around room temperature, |ΔSmax| values increment under field changes 20, 40 kOe...
The MnBi low temperature phase with high value and positive coefficient of its coercivity has a potential for production both the nanocomposite hybrid permanent magnets. In this report, we present our results investigation fabrication Mn55Bi45 nanoparticles by using energy ball milling method. alloy was first arc-melted then ball-milled various time 0.25–8 h in different environments Argon, Alcohol, Petrol Xylene. resulted powder subsequently annealed at temperatures 200 250°C periods 0.5–4...
We have designed an excellent visible-light-driven and high-performance photocatalyst with a Ag-Cu2O-ZnO nanowire heterostructure in our work by combining the hydrothermal approach plasma–liquid technology. The structural morphological characteristics optical properties of samples were evaluated using X-ray diffraction, field-emission scanning electron microscopy, spectrophotometry, respectively. results show that Ag nanoparticles are mainly positioned on Cu2O nanoclusters compared ZnO...