RESUMO
In this work, we present magnetic phase diagrams of a RuSr(2)Eu(1.5)Ce(0.5)Cu(2)O(10-δ) (Ru-1222) superconducting ferromagnet derived from its static and dynamic magnetic responses, measured by temperature and field dependences of dc magnetization and nonlinear ac susceptibility in both low and high magnetic fields. Comparison of magnetic phase diagrams of phase pure and impure samples singles out the intrinsic and extrinsic magnetic features, naturally proposing a unified model of Ru-1222 magnetic behaviour. The results considered within the proposed interpretation indicate full agreement between static and dynamic properties which, if measured in combination, effectively complement each other, uncovering existing ambiguities.
Assuntos
Rutênio/química , Fenômenos Químicos , Cristalização , Campos Magnéticos , Magnetismo , Propriedades de Superfície , TemperaturaRESUMO
Applying the Kramers-Kronig consistent procedure, developed earlier, we investigate in detail the formation of the quasiparticle spectrum along the nodal direction of high-Tc cuprates. The heavily discussed "70 meV kink" on the renormalized dispersion exhibits a strong temperature and doping dependence when purified from structural effects such as bilayer splitting, diffraction replicas, etc. This dependence is well understood in terms of fermionic and bosonic constituents of the self-energy. The latter follows the evolution of the spin-fluctuation spectrum, emerging below some doping dependent temperature and sharpening below Tc, and is mainly responsible for the formation of the kink in question.
RESUMO
Copolymers of N,N-diethylacrylamide and N-acryloylphthalimide with lower critical solution temperature (LCST) were synthesized by radical copolymerization. Polymeric systems with antithrombin activity and LCST were prepared via a reaction of amino groups of hirudin with phthalimide groups of the copolymers. On increasing hirudin content, LCST of the polymeric systems increased. The antithrombin activity of polymeric systems obtained by hirudin immobilization on copolymer carriers was inversely related to the content of the copolymer, amounting to 6% of the activity of native hirudin.
Assuntos
Antitrombinas/síntese química , Sistemas de Liberação de Medicamentos , Polímeros/síntese química , Temperatura , Acrilamidas/química , Antitrombinas/química , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Hirudinas/química , Ftalimidas/química , Polímeros/químicaRESUMO
The stability of polyacrylamide hydrogel, modified by ovomucoid with immobilized insulin was studied at different pH of external medium. At 3.8 < pH < 5.5 insulin binds to the gel, due to electrostatic interaction between ovomucoid and insulin molecules.