排序方式: 共有51条查询结果,搜索用时 15 毫秒
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该文以兼顾系柱大推力和航行速度为设计目标的推式导管舵桨为研究对象,采用RANS方法中的SST k-ω模型,选择Schnerr-Sauer空泡模式,考察航行和系柱工况下的空泡数值模拟结果,并与模型试验结果相比,得到的空泡形态大致与试验结果相符合,能够很好地捕捉到叶背片空泡、叶面空泡、梢涡空泡、梢隙空泡。因为吊柱与导管、导管桨的距离较近,出现了连体涡空泡现象,文中进一步分析了吊柱-导管桨距离与连体涡强度的关系,提出抑制连体涡空泡产生的距离(即距离大于0.35D,可基本消除连体涡空泡),对基于空泡性能的导管舵桨优化设计提供了重要支撑。 相似文献
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Face hallucination via patch-pairs leaning based methods has been wildly used in the past several years. Some position-patch based face hallucination methods have been proposed to improve the representation power of image patch and obtain the optimal regressive weighted vector. The rationale behind the position-patch based face hallucination is the fact that human face is always highly structured and consequently positioned and it plays an increasingly important role in the reconstruction. However, in the existing position-patch based methods, the probe image patch is usually represented as a linear combination of the corresponding patches of some training images, and the reconstruction residual is usually measured using the vector norm such as 1-norm and 2-norm. Since the vector norms neglect two-dimensional structures inside the residual, the final reconstruction performance is not very satisfactory. To cope with this problem, we present a weighted nuclear-norm constrained sparse coding (WNCSC) model for position-patch based face hallucination. In addition, an efficient algorithm for the WNCSC is developed using the alternating direction method of multipliers (ADMM) and the method of augmented Lagrange multipliers (ALM). The advantages of the proposed model are twofold: in order to fully make use of low-rank structure information of the reconstruction residual, the weighted nuclear norm is applied to measure the residual matrix, which is able to alleviate the bias between input patches and training data, and it is more robust than the Euclidean distance (2-norm); the more flexible selection method for rank components can determine the optimal combination weights and adaptively choose the relevant and nearest hallucinated neighbors. Finally, experimental results prove that the proposed method outperforms the related state-of-the-art methods in both quantitative and visual comparisons. 相似文献
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压密注浆在宁西铁路涵洞地基加固中的应用 总被引:2,自引:2,他引:0
利用压密注浆技术对湿陷性黄土地区既有铁路涵洞地基进行加固,能有效地控制涵洞不均匀沉降,消除黄土的湿陷性,提高涵洞地基承载力。具有施工对行车干扰小、质量容易保证、工程造价低等特点,值得推广应用。 相似文献
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介绍了埋地燃气管道外防腐层老化状况评价标准,以沥青外防腐层为例,通过应用马尔可夫链理论,阐述了基于逆阵的外防腐层老化状况预测的方法,从而为确定整条管线外防腐层老化状况分布提供了理论依据。 相似文献
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