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《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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In the training of feedforward neural networks,it is usually suggested that the initial weights should be small in magnitude in order to prevent premature saturation.The aim of this paper is to point out the other side of the story:In some cases,the gradient of the error functions is zero not only for infinitely large weights but also for zero weights.Slow convergence in the beginning of the training procedure is often the result of sufficiently small initial weights.Therefore,we suggest that,in these cases,the initial values of the weights should be neither too large,nor too small.For instance,a typical range of choices of the initial weights might be something like(0.4,0.1) ∪(0.1,0.4),rather than(0.1,0.1) as suggested by the usual strategy.Our theory that medium size weights should be used has also been extended to a few commonly used transfer functions and error functions.Numerical experiments are carried out to support our theoretical findings. 相似文献
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刘秋成 《吉林化工学院学报》2014,(8):88-90
叙事能力即话语能力,培养学生的叙事能力是大学英语教学重要目标之一。叙事教学法以叙事为中心,强调学生叙事能力发展,注重叙事对学生的认知作用及其个性化学习。针对叙事教学法的特点和大学英语教学的要求,探寻大学生叙事能力的培养的途径,以期提高教学实际质量。 相似文献
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随着物联网的广泛应用,如何有效实现轻量级密码算法成为近年的研究热点。对2011年提出的TWINE加密算法进行了硬件优化实现,相同的轮运算只实现一次,采用重复调用方式完成。TWINE算法总共有36轮运算,其中前35轮运算结构相同,可以重复调用实现,而第36轮相比前35轮在结构上少了块混淆,因此原始算法最多只能进行35轮重复调用。直接进行36轮循环调用运算,同时在36轮循环运算完成后构造一个块混淆逆运算,运算一次块混淆逆运算即可使输出密文正确。这样使TWINE最后的第36轮不必重新实现,而是直接复用前面可重复轮函数模块,只需增加一个比原始算法最后一轮运算相对简单的块混淆逆运算。下载到FPGA上的实验结果表明,优化后的TWINE密码算法在面积上减少了2204个Slices,系统速率提高了5倍。 相似文献
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Yue Li Gaobo Yang Yapei Zhu Can Liu Kai Liu 《Journal of Real-Time Image Processing》2016,12(3):575-582
Multiview video coding (MVC) exploits mode decision, motion estimation and disparity estimation to achieve high compression ratio, which results in an extensive computational complexity. This paper presents an efficient mode decision approach for MVC using a macroblock (MB) position constraint model (MPCM). The proposed approach reduces the number of candidate modes by utilizing the mode correlation and rate distortion cost (RD cost) in the previously encoded frames/views. Specifically, the mode correlations both in the temporal-spatial domain and the inter-view are modeled with MPCM. Then, MPCM is exploited to select the optimal prediction direction for the current encoding MB. Finally, the inter mode is early determined in the optimal prediction direction. Experimental results show that the proposed method can save 86.03 % of encoding time compared with the exhaustive mode decision used in the reference software of joint multiview video coding, with only 0.077 dB loss in Bjontegaard delta peak signal-to-noise ratio (BDPSNR) and 2.29 % increment of the total Bjontegaard delta bit rate (BDBR), which is superior to the performances of state-of-the-art approaches. 相似文献
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Huffman编码作为一种高效的不等长编码技术正日益广泛地在文本、图像、视频压缩及通信、密码等领域得到应用。Java语言是一种目前比较流行的、面向对象的程序设计语言,文章就如何利用Java的优先队列结构建立Huffman编码树进行了探讨,并给出了编码与反编码程序。 相似文献
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