We study connections between four different types of results that are concerned with vector-valued functions u : Ω → R of class L(Ω) on a domain Ω ⊂ R: Coercivity results in H(Ω) relying on div and curl, the Helmholtz decomposition, the construction of vector potentials, and the global div-curl lemma. Key-words: Friedrichs inquality, coercivity, div-curl lemma, compensated compactness

Abstract. Some criteria for the asymptotic stability of nonlinear stochastic partial differential equations with variable delays are presented. A coercivity condition plays the role of an exponential stability criterion. Consequently, under the coercivity condition almost all the trajectories of the nonstationary solutions of the given stochastic system finally tend exponentially to zero. Two e...

Fe3O4 nanoparticles were synthesizedviaa simple chemical reaction between FeCl2.4H2O and Fe(NO3)3.9H2O under nitrogen atmosphere at room temperature, and then nanoparticles were added to cellulose acetate (CA) polymer. The influence of nanoparticles on the thermal properties of CA polymeric matrix was studied using the...

The structures and magnetic properties of Pr–Fe–Al alloys produced by the metallic mold casting method were investigated. The Pr–Fe–Al alloy consisted of the amorphous phase together with the non-ferromagnetic Pr phase. Magnetic measurements confirmed that the origin of coercivity in the alloys was the amorphous phase. It was found that the Curie temperature and coercivity of the alloys were st...

aisi 4340 steel is one of the super strong steels that can be selected for different applications. by designing theproper cycles of heat treatment, the optimum microstructure and properties of this steel can be achieved. in thisstudy, different heat treatment cycles were introduced to achieve the optimum microstructure and improve themechanical and magnetic properties of aisi 4340 steel. the re...

the lead ferrite (pbfe12o19) nanoparticles were prepared by a simple and short time microwave method. lead nitrate, iron nitrate hydrate, surfactants, and ethylene glycol were used as precursor materials. the effect of surfactants on the morphology and particle size of the magnetic products was investigated. the prepared magnetic products were study by x-ray diffraction (xrd), scanning electron...

Fe(x)Pt(y)Au(100-x-y) nanoparticles of size 3.5 nm were prepared by polyol reduction of platinum acetylacetonate and gold acetate and the thermal decomposition of iron pentacarbonyl. The as-synthesized nanoparticles with disordered fcc structure were then heat treated to transform to the L1(0) structure with high magnetocrystalline anisotropy. By tuning the stoichiometry of the Fe(x)Pt(y)Au(100...

Thin 001 textured FePt and CoPt polycrystalline films (5 nm) were deposited with an MgO polycrystalline underlayer on an oxidized Si substrate followed by a Rapid Thermal Annealing (RTA) process. Structural analysis indicated the samples to be fully ordered after 10 minutes (min) of RTA at 700 C. The magnetic hysteresis exhibited strong perpendicular anisotropy and a coercivity ( ) between 6 an...

In this study, we demonstrated the magnetoelectric control of magnetic thin films. (111)-textured Pd/Ni/ Pd thin films were prepared on mica/lead zirconium titanate (PZT) substrates for the investigation. The reversible modulation of magnetic coercivity in Ni films was observed through the electric-voltagecontrolled strain variation from the PZT substrate. For 14 nm Ni film, the applied electri...