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1.
《Ceramics International》2022,48(22):32973-32985
Multilayer structure design is one of the most promising methods for improving the comprehensive performance of AlCrN-based hard coatings applied to cutting tools. In this study, four types of AlCrSiN/AlCrVN/AlCrNbN multilayer coatings, with different modulated thicknesses, were deposited to investigate their microstructure, mechanical, tribological, and oxidizing properties. All multilayer coatings exhibited grain growth along the crystallographic plane of (200) with a NaCl-type face-centered cubic (FCC) structure. The results show that, as the modulation thickness decreases from ~35 nm to ~10 nm, (1) the grain refinement effect is increasingly evident; (2) all multilayer coatings show a hardness of >30 GPa and an elastic modulus of >300 GPa. Both the ability to resist elastic strain to failure and the plastic deformation of multilayer coatings increase. In addition, their resistance to cracking reduces; (3) the wear rates of these multilayer coatings reduce successively from 1.78 × 10?16 m3 N?1 m?1 to 7.7 × 10?17 m3 N?1 m?1. This is attributed to an increase in self-lubricating VOx and a decrease in adhesives from the counterparts; (4) the best high-temperature oxidation resistance was obtained for the multilayer coating with a modulated thickness of ~15 nm. 相似文献
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《Ceramics International》2020,46(4):4148-4153
The ferroelectric photovoltaic (FPV) effect obtained in inorganic perovskite ferroelectric materials has received much attention because of its large potential in preparing FPV devices with superior stability, high open-circuit voltage (Voc) and large short-circuit current density (Jsc). In order to obtain suitable thickness for the ferroelectric thin film as light absorption layer, in which, the sunlight can be fully absorbed and the photo-generated electrons and holes are recombined as few as possible, we prepare Pb0.93La0.07(Zr0.6Ti0.4)0.9825O3 (PLZT) ferroelectric thin films with different layer numbers by the sol-gel method and based on these thin films, obtain FPV devices with FTO/PLZT/Au structure. By measuring photovoltaic properties, it is found that the device with 4 layer-PLZT thin film (~300 nm thickness) exhibits the largest Voc and Jsc and the photovoltaic effect obviously depends on the value and direction of the poling electric field. When the device is applied a negative poling electric field, both the Voc and Jsc are significantly higher than those of the device applied the positive poling electric field, due to the depolarization field resulting from the remnant polarization in the same direction with the built-in electric field induced by the Schottky barrier, and the higher the negative poling electric field, the larger the Voc and Jsc. At a -333 kV/cm poling electric field, the FPV device exhibits the most superior photovoltaic properties with a Voc of as high as 0.73 V and Jsc of as large as 2.11 μA/cm2. This work opens a new way for developing ferroelectric photovoltaic devices with good properties. 相似文献
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The proposed work involves the multiobjective PSO based adaption of optimal neural network topology for the classification of multispectral satellite images. It is per pixel supervised classification using spectral bands (original feature space). This paper also presents a thorough experimental analysis to investigate the behavior of neural network classifier for given problem. Based on 1050 number of experiments, we conclude that following two critical issues needs to be addressed: (1) selection of most discriminative spectral bands and (2) determination of optimal number of nodes in hidden layer. We propose new methodology based on multiobjective particle swarm optimization (MOPSO) technique to determine discriminative spectral bands and the number of hidden layer node simultaneously. The accuracy with neural network structure thus obtained is compared with that of traditional classifiers like MLC and Euclidean classifier. The performance of proposed classifier is evaluated quantitatively using Xie-Beni and β indexes. The result shows the superiority of the proposed method to the conventional one. 相似文献
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基于调谐频率与分频处理的高分辨率反演技术 总被引:12,自引:2,他引:10
讨论了基于调谐频率与分频处理的高分辨率反演技术,给出了方法的基本原理,即利用地震数据的调谐频率和分频处理分析,半定量地确定储层厚度,并将其作为地震反演的约束条件。方法的实现过程是:通过层状地质模型的地震正演模拟,建立不同主频子波时地层厚度与调谐频率的关系;利用地震资料时-频分析技术,实现地震资料分频处理;利用合成地震记录标定地震子波主频;利用分频处理结果,借助于调谐频率分析与调谐振幅分析,给出地震反演约束条件;利用反演算法消除地震子波影响,提高和拓展地震资料的频带范围,实现储层的高分辨率成像。普光地区的应用实例表明,调谐频率与分频处理的高分辨率反演方法无需对储层空间变化规律进行假设,适用于强非均质碳酸盐岩储层的高分辨率成像。 相似文献
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1 Influence of PAMAon Boundary Fil mFormation and Friction1.1 Experi mental methodsUltra-thin optical interferometry has been used tostudy thinlubricating fil ms for more than a decade and theexperi mental details of this technique have been reportedpreviously[1].The principle of the test setup is shown inFigure1.A polished steel ball is loaded and rolled againstthe flat surface of a glass disc that is coated with a thinsemi-reflecting chromiumlayer and a silica spacer of about500nmthickne… 相似文献
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工业管道测厚的几点问题探讨 总被引:2,自引:0,他引:2
超声波测厚在腐蚀监测上应用越来越广泛,为让这项检测技术更准确、更可靠,充分发挥功效,文章就工业管道测厚中测厚数据处理、测厚点选择、高温问题以及其它影响因素等几个方面进行了探讨。 相似文献