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Yi Ren Xian-bo Shi Zhen-guo Yang Yi-yin Shan Wei Ye Gui-xi Cai Ke Yang 《钢铁研究学报(英文版)》2021,28(6):752-761
The effect of microstructures on strength, strain capacity and low temperature toughness of a micro-alloyed pipeline steel was elucidated. Five various dual-pha... 相似文献
73.
为了增强BP网隐层的归纳能力,文[1]提出了调整权重的熵方法,我们在文[2]中给出了基于能量函数的改进算法,本文把文[1]算法与文[2]算法结合在一起给出了新算法,实验证明此算法既能大大加快收敛速度,又可增强网的归纳能力。 相似文献
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A broadband 8‐antenna multiple‐input and multiple‐output (MIMO) system working for 5G new radio N77 (3.3‐4.2 GHz) in mobile terminals is proposed. In particular, each antenna element/unit consists of a monopole‐type meandered branch and an inverted U‐shaped self‐isolated antenna branch; and the antenna unit is fed by the meandered branch. The antenna unit has two resonances generated separately by each branch of the antenna unit. Since the monopole couples strongly with the self‐isolated antenna element that has the inherent self‐isolation characteristics, quite good isolation for the broadband 8‐antenna MIMO system can be obtained. The results such as antenna efficiency, radiation patterns, envelope correlation coefficient, and channel capacity are also presented. 相似文献
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This paper addresses the orientation-singularity and orientationability analyses of a special class of the Stewart–Gough parallel manipulators whose moving and base platforms are two similar semi-symmetrical hexagons. Employing a unit quaternion to represent the orientation of the moving platform, an analytical expression representing the singularity locus of this class of parallel manipulators in a six-dimensional Cartesian space is obtained. It shows that for a given orientation, the position-singularity locus is a cubic polynomial expression in the moving platform position parameters, and for a given position, the orientation-singularity locus is an analytical expression but not a polynomial directly with respect to the mobile platform orientation parameters. Further inspection shows that for the special class of parallel manipulators, there must exist a nonsingular orientation void in the orientation space around the orientation origin for each position in the position-workspace. Therefore, a new performance index referred to as orientationability is introduced to describe the orientation capability of the special class of manipulators at a given position. A discretization algorithm is proposed for the computation of the orientationability of the special class of manipulators. Moreover, effects of the design parameters and position parameters on the orientationability are investigated in details. Based on the orientationability performance index, another novel performance index referred to as practical orientationability is presented which represents the practical orientation capability of the manipulator at a given position. The practical orientationability not only can satisfy all the kinematic demands and constraints of such class of manipulators, but also can guarantee that the manipulator is nonsingular. 相似文献
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A staggered distribution of vegetation is very common in nature,which might significantly affect the flow structure.To investigate its impact,three rows of stag... 相似文献
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