527 research outputs found

    Analytical expression of the magneto-optical Kerr effect and Brillouin light scattering intensity arising from dynamic magnetization

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    Time-resolved magneto-optical Kerr effect (MOKE) and Brillouin light scattering (BLS) spectroscopy are important techniques for the investigation of magnetization dynamics. Within this article, we calculate analytically the MOKE and BLS signals from prototypical spin-wave modes in the ferromagnetic layer. The reliability of the analytical expressions is confirmed by optically exact numerical calculations. Finally, we discuss the dependence of the MOKE and BLS signals on the ferromagnetic layer thickness

    Development of a method for controlling stress - strain state of concrete in conditions of uniaxial compression

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    The researches of dependence of the parameters of electrical response to mechanical impact with different stress at concrete sample were carried out. It is defined that the attenuation coefficient is changed and signal spectrum is displaced to low-frequency region at the approach of the load to the destructive

    Reentrant Superconductivity and Superconducting Critical Temperature Oscillations in F/S/F trilayers of Cu41Ni59/Nb/Cu41Ni59 Grown on Cobalt Oxide

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    Ferromagnet/Superconductor/Ferromagnet (F/S/F) trilayers constitute the core of a superconducting spin valve. The switching effect of the spin valve is based on interference phenomena occurring due to the proximity effect at the S/F interfaces. A remarkable effect is only expected if the core structure exhibits strong critical temperature oscillations, or most favorable, reentrant superconductivity, when the thickness of the ferromagnetic layer is increased. The core structure has to be grown on an antiferromagnetic oxide layer (or such layer to be placed on top) to pin by exchange bias the magnetization-orientation of one of the ferromagnetic layers. In the present paper we demonstrate that this is possible, keeping the superconducting behavior of the core structure undisturbed.Comment: 22 pages, 12 figures, 1 tabl

    Experimental and theoretical analysis of the upper critical field in FSF trilayers

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    The upper critical magnetic field H_{c2} in thin-film FSF trilayer spin-valve cores is studied experimentally and theoretically in geometries perpendicular and parallel to the heterostructure surface. The series of samples with variable thicknesses of the bottom and of the top Cu_{41}Ni_{59} F-layers are prepared in a single run, utilizing a wedge deposition technique. The critical field H_{c2} is measured in the temperature range 0.480.4-8 K and for magnetic fields up to 9 Tesla. A transition from oscillatory to reentrant behavior of the superconducting transition temperature versus F-layers thickness, induced by an external magnetic field, has been observed for the first time. In order to properly interpret the experimental data, we develop a quasiclassical theory, enabling one to evaluate the temperature dependence of the critical field and the superconducting transition temperature for an arbitrary set of the system parameters. A fairly good agreement between our experimental data and theoretical predictions is demonstrated for all samples, using a single set of fit parameters. This confirms adequacy of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) physics in determining the unusual superconducting properties of the studied Cu_{41}Ni_{59}/Nb/Cu_{41}Ni_{59} spin-valve core trilayers.Comment: 16 pages, 7 figures; published versio

    Memory Effect and Triplet Pairing Generation in the Superconducting Exchange Biased Co/CoOx/Cu41Ni59/Nb/Cu41Ni59 Layered Heterostructure

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    We fabricated a nanolayered hybrid superconductor-ferromagnet spin-valve structure, the resistive state of which depends on the preceding magnetic field polarity. The effect is based on a strong exchange bias (about -2 kOe) on a diluted ferromagnetic copper-nickel alloy and generation of a long range odd in frequency triplet pairing component. The difference of high and low resistance states at zero magnetic field is 90% of the normal state resistance for a transport current of 250 {\mu}A and still around 42% for 10 {\mu}A. Both logic states of the structure do not require biasing fields or currents in the idle mode.Comment: 9 pages, 4 figures, Accepted to Applied Physics Letter

    Relatório de gestão 2001-2004.

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    Embrapa Informática Agropecuária. Pesquisa e Desenvolvimento. Ações gerenciais estratégicas. Transferência de tecnologia e comunicação empresarial. Gestão Institucional. Prêmios recebidos. Infra-estrutura física. Gestão de Recursos Financeiros. Gestão de Recursos Humanos.bitstream/CNPTIA/10727/1/doc51.pdfAcesso em: 29 maio 2008

    Recuperação de informação: Bases de Dados da Pesquisa Agropecuária.

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    O artigo relata dois casos de sucesso de aplicações na Internet para organização e disponibilização de informação (Google e Yahoo) , apresenta os problemas encontrados e os requisitos para o novo sistema de busca textual, a solução tecnológica escolhida, bem como os ganhos obtidos com a migração para software livre.SBIAgro 2007

    AINFO: sistema de informação para gerenciamento de bases de dados documentais e processos bibliográficos.

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    AINFO é um Sistema de Informação para Gerenciamento de Bases de Dados Documentais e Processos Bibliográficos, utilizado em toda a Embrapa e que tem sido fortemente disseminado no Sistema Nacional de Pesquisa Agropecuária desde a sua primeira versão, proporcionando um canal permanente para troca de informações entre os usuários envolvidos com o universo agropecuário. Este artigo apresenta a metodologia de implantação do AINFO, sua estrutura focalizando os seus módulos básicos e os relacionamentos entre as bases de dados e destaca, ainda, alguns dos recursos para gerenciamento e recuperação de informação disponíveis. Atualmente, o sistema encontra-se disponível para diversas plataformas computacionais, a saber: PC/MS-DOS, SUN/Solaris, IBM/AIX e HP/HP-UX.Agrosoft 97

    Myostatin Is Elevated in Congenital Heart Disease and After Mechanical Unloading

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    Myostatin is a negative regulator of skeletal muscle mass whose activity is upregulated in adult heart failure (HF); however, its role in congenital heart disease (CHD) is unknown.We studied myostatin and IGF-1 expression via Western blot in cardiac tissue at varying degrees of myocardial dysfunction and after biventricular support in CHD by collecting myocardial biopsies from four patient cohorts: A) adult subjects with no known cardiopulmonary disease (left ventricle, LV), (Adult Normal), (n = 5); B) pediatric subjects undergoing congenital cardiac surgery with normal RV size and function (right ventricular outflow tract, RVOT), (n = 3); C) pediatric subjects with worsening but hemodynamically stable LV failure [LV and right ventricle (LV, RV,)] with biopsy collected at the time of orthotopic heart transplant (OHT), (n = 7); and D) pediatric subjects with decompensated bi-ventricular failure on BiVAD support with biopsy collected at OHT (LV, RV, BiVAD), (n = 3).The duration of HF was longest in OHT patients compared to BIVAD. The duration of BiVAD support was 4.3±1.9 days. Myostatin expression was significantly increased in LV-OHT compared to RV-OHT and RVOT, and was increased more than double in decompensated biventricular HF (BiVAD) compared to both OHT and RVOT. An increased myostatin/IGF-1 ratio was associated with ventricular dysfunction.Myostatin expression in increased in CHD, and the myostatin/IGF-1 ratio increases as ventricular function deteriorates. Future investigation is necessary to determine if restoration of the physiologic myostatin/IGF-1 ratio has therapeutic potential in HF
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