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991.
《印度化学会志》2022,99(3):100362
Cu substituted nickel-zinc ferrites with composition Ni0.2CuxZn0.8-xFe2O4 (x ?= ?0 to 0.8) were developed with the technique of citrate-gel method. Rietveld analysis confirmed Fd-3m space grouped cubic spinel structure of single phase. Dislocation density (?) and packing factor percentage (%) of samples under study increase with increased Cu composition. The fine and uniform structure was confirmed from the studies of morphology index. Measurements on electrical resistivity were taken up by using the two-probe method at high temperatures. Arrhenius plots confirm an increase in observed resistivity (Ω) of ferrite samples with a temperature increase. The energy of activation in the ferromagnetic region (EF) is less when compared to that of the paramagnetic region (EP). The hopping mechanism decreases Curie temperature, while the activation energy of hopping increases with an increase in Cu substitution. Mobility of charge carriers and temperature are inversely correlated. 相似文献
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AbstractWe present an interior proximal method for solving constrained nonconvex optimization problems where the objective function is given by the difference of two convex function (DC function). To this end, we consider a linearized proximal method with a proximal distance as regularization. Convergence analysis of particular choices of the proximal distance as second-order homogeneous proximal distances and Bregman distances are considered. Finally, some academic numerical results are presented for a constrained DC problem and generalized Fermat–Weber location problems. 相似文献
993.
Honghong Shao Xiaojing Xu Ji Wang Rui Zhai Xiaojing Wang 《Applied Surface Science》2010,257(5):1649-9093
Recent progress in ultrafine-grained/nano-grained (UFG/NG) titanium permits a consideration for TiO2 films deposited on nano-grained titanium for antithrombogenic application such as artificial valves and stents. For this paper, the microstructure, interface bonding, surface energy, and blood compatibility features of TiO2 films deposited by direct current magnetron reactive sputtering technology on NG titanium and coarse-grained (CG) titanium were investigated. The results show that the nanocrystallization of titanium substrate has a significant influence on TiO2 films. At the same deposition parameters, the content of rutile phase of TiO2 film was increased from 47% (on the CG titanium substrate) to 72% (on the NG titanium substrate); the adhesion of TiO2 film was improved from 5.8 N to 17 N; the surface energy was reduced from 6.37 dyn/cm to 3.01 dyn/cm; the clotting time was improved from 18 min to 28 min; the platelets accumulation and pseudopodium of adherent platelets on TiO2 film on NG titanium were considerably reduced compared to that on CG titanium. The present results demonstrate the possibility of improving the blood compatibility of TiO2 film through the approach of substrate nanocrystallization. Also it may provide an attractive idea to prepare stents with biological coatings of more outstanding blood compatibility and interface bonding. 相似文献
994.
M.B. Shelar P.A. Jadhav D.R. Patil B.K. Chougule Vijaya Puri 《Journal of magnetism and magnetic materials》2010,322(21):3355-3358
The cadmium substituted nickel ferrites Ni1−xCdx Fe2O4 (x=0.2, 0.4, 0.6) has been prepared by the self-propagating auto combustion method. Phase identification of the samples was studied by XRD patterns which are characteristics of cubic spinel structure ferrites. As the content of cadmium in the ferrites increases the lattice parameter. The tetrahedral and octahedral vibrations in the samples were studied by Fourier Transform Infrared (FT-IR) spectra. The SEM study reveals the fine-grained nature of ferrites with little agglomeration. The decrease in the drift mobility is found with increase in cadmium content. DC resistivity indicates the semiconducting nature of the samples. The Super Quantum Interference Device measurements were taken to study the magnetic properties of the samples. 相似文献
995.
S. Nakayama T. HonmaK. Nakagawa A. SaitoS. Ohshima 《Physica C: Superconductivity and its Applications》2010,470(20):1042-1044
We investigated the dc magnetic field and temperature dependences of the microwave surface resistance (Rs) of YBa2Cu3Oy (YBCO) and DyBa2Cu3Oy (DyBCO) superconducting thin films. The YBCO and DyBCO thin films, each with a thickness of 300, 500, or 700 nm, were deposited on MgO (1 0 0) substrates by the thermal co-evaporation method. The Rs was measured using the dielectric resonator method. A dc magnetic field of up to 5.0 T was applied parallel to the c-axis of the superconducting thin films. The results showed that the Rs value had almost the same temperature dependence at various thicknesses in a zero-external field. The Rs of the YBCO and DyBCO thin films increased with the applied dc magnetic field. The DyBCO thin films showed weaker magnetic field dependence of Rs than the YBCO thin films. The Rs ratio (defined as Rs(5 T)/Rs(0 T)) linearly increased with the film thickness. These results show that pinning strength decreased with an increasing film thickness. 相似文献
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本文提出了一种可以完成素材的自动分类与数据库管理的视频自动分类系统,通过综合分析体育节目压缩域和解压缩域的特征,利用颜色和形状相结合的方式确定是否符合特定类型素材的特征,从而完成素材的归类管理.实验证明该系统可以比较准确的对特定类型的体育视频进行自动分类和数据库管理. 相似文献