376 resultados para 1335


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The nanocomposites of xTiO(2)+(1-x)Ni0.53Cu0.12Zn0.35Fe2O4 (where 0 <= x >= 1) were prepared using microwave hydrothermal (M H) method at 165 degrees C/45 min. The as-synthesized powders were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The particle size of the powder varies from 18 to 35 nm. The as prepared powders were densified at 500 degrees C/30 min using microwave sintering method. The sintered composites were characterized by XRD and scanning electron microscopy (SEM). The bulk densities of the present composites were increasing with the addition of TiO2. The grain sizes of all the composite vary between 65 nm and 90 nm. The addition of TiO2 to ferrite increased the dielectric properties (epsilon' and epsilon `') also the resonant frequency of all the composites was found to be greater than 1 GHz. The imaginary part of permeability mu `' was found to increase with an increase of TiO2.

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Structural studies in this laboratory encompass four of the five major classes of plant lectins, including the one discovered by us. In addition to addressing issues specific to individual lectins, the work provided insights into protein folding, quaternary association and generation of ligand specificity. Legume and beta-prism fold lectins constitute families of proteins in which small alterations in essentially the same tertiary structure lead to large variations in quaternary structure, including that involving an open structure. Strategies for generating ligand specificity include water bridges, variation in loop length, post translational modification and oligomerization. Three of the structural classes investigated have subunits with three-fold symmetry. The symmetry in the structure is reflected in the sequence to different extents in different subclasses. The evolutionary implications of this observation have been explored. The work on lectins has now been extended to those from mycobacteria.

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All solid state batteries are essential candidate for miniaturizing the portable electronics devices. Thin film batteries are constructed by layer by layer deposition of electrode materials by physical vapour deposition method. We propose a promising novel method and unique architecture, in which highly porous graphene sheet embedded with SnO2 nanowire could be employed as the anode electrode in lithium ion thin film battery. The vertically standing graphene flakes were synthesized by microwave plasma CVD and SnO2 nanowires based on a vapour-liquid-solid (VLS) mechanism via thermal evaporation at low synthesis temperature (620 degrees C). The graphene sheet/SnO2 nanowire composite electrode demonstrated stable cycling behaviours and delivered a initial high specific discharge capacity of 1335 mAh g(-1) and 900 mAh g(-1) after the 50th cycle. Furthermore, the SnO2 nanowire electrode displayed superior rate capabilities with various current densities.

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By making use of the evolution equation of the damage field as derived from the statistical mesoscopic damage theory, we have preliminarily examined the inhomogeneous damage field in an elastic-plastic model under constant-velocity tension. Three types of deformation and damage field evolution are presented. The influence of the plastic matrix is examined. It seems that matrix plasticity may defer the failure due to damage evolution. A criterion for damage localization is consistent with the numerical results.

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La mastitis se refiere a la inflamación de la glándula mamaria, causado por varios factores destacándose entre ellos, los físicos, mecánicos e infecciosos. Se caracteriza por las alteraciones físicas, químicas y bacteriológicas de la leche, también por modificaciones patológicas del tejido glándular. Con el objetivo de determinar la prevalencia en Juigalpa, Chontales, se desarrolló un "ESTUDIO EPIDEMIOLOGICO SOBRE LA PREVALENCIA DE MASTITIS SUBCLINICA EN EL 100 % DE LAS VACAS EN ORDEÑO, EN 9 UNIDADES DE PRODUCCION UBICADAS EN JUIGALPA, CHONTALES." por lo que se realizó un diagnostico a 2115 vacas, para nuestro estudio epidemiológico utilizamos el método de diagnóstico California Mastitis Test. Los resultados obtenidos revelan una prevalencia global de 34%, siendo de esta mastitis clínica 5.01% y una subclínica de 29.26% en nuestro estudio también aportamos la importancia del uso de medidas higiénicas, números de partos, mes del año son variables en el surgimiento de la mastitis subclínica por lo que en la zona donde realizamos nuestra investigación se considera una afectada por mastitis. Por lo que recomendamos establecer programas de vigilancia y control permanente de la mastitis subclínica en cada unidad de producción.

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在流体力学领域,流体自由面变化是非常重要的物理现象.研究了矩形池内由液池两端温度差引起的热毛细对流的流体表面变形和表面波问题.该液池的水平横截面尺寸为52mm×42mm,液池内盛有液层厚度为3.5mm的1000号硅油.实验过程中液池两端温度差逐渐增加,液层内流体的流动从稳定的对流逐渐转变为不稳定状态.实验中将Michelson光学干涉测量技术与图像处理技术相结合,发展形成一种实时诊断流体表面形貌的实验测量系统.应用Fourier变换方法对激光干涉条纹图像进行了计算和分析,得到了流体表面变形和表面波的定量的实验结果.实验结果表明在热毛细对流的发展过程中,首先出现流体的表面变形,液池两端温度差达到一定值之后,在该变形的基础上,会有表面波的信息叠加在其中,该表面变形和表面波与流体的温度梯度、表面张力等有直接的关系;表面波隐藏在表面变形内.

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In recent years, difficulties encountered in obtaining ground-water supplies with acceptable chemical characteristics in the Myakka River basin area led to the implementation of a test drilling program. Under this program, well drilling and data collection were executed in such a manner that all water-producing zones of the local aquifers, together with the quality and quantity of the water available, were effectively identified. A step-drilling method was utilized which allowed the collection of formation cuttings, water samples, and water-level data, from isolated zones in the well as drilling proceeded. The step drilling procedure is described. The driller's logs, geophysical logs, and chemical quality of water tables are presented.(Document has 66 pages.)