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481.
482.
Shenggao Yang Libin Weng Yaguang Zhu Xu Yang Sihui Hu Peikang Xu Huan Zhang Weidong Pan Jie Shang Xing Su 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(1):46-55
We used the TEC (Total electron content) data of 5 min resolution obtained from the Madrigal database during solar-maximum winter (Nov. 6, 2000–Feb. 4, 2001) to study statistically the polar ionospheric plasma distribution response to different intensity and orientation of IMF By/Bz components. The sunlit high-density plasma extension from dayside to nightside is favored in negative IMF By and Bz conditions. With the magnitude of the negative Bz increasing, the time range corresponding to the distinct high-density extension feature expands, and the plasma density along the extension path enhances, which can be attributed to the interaction between dayside solar-produced ionization whose poleward limit is decided by terminator and convection extent mainly modulated by IMF Bz component. As for IMF By component influence on the sunlit plasma extension, the combination effect of convection and corotation electric fields is necessary to be considered. 相似文献
483.
A state-of-the-art review on monolayer electroplated and brazed cubic boron nitride (CBN) superabrasive wheels for grinding metallic materials has been provided in this article. The fabrication techniques and mechanisms of the monolayer CBN wheels are discussed. Grain distri-bution, wheel dressing, wear behavior, and wheel performance are analyzed in detail. Sample appli-cations of monolayer CBN wheel for grinding steels, titanium alloys, and nickel-based superalloys are also provided. Finally, this article highlights opportunities for further investigation of mono-layer CBN grinding wheels. 相似文献
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Design and analysis of spiral bevel gears with seventh-order function of transmission error 总被引:2,自引:0,他引:2
This paper proposes a new approach to mial function of transmission error (TE) for spiral design and implement a seventh-order polyno- bevel gears with an aim to reduce the running vibration and noise of gear drive and improve the loaded distribution of the tooth. Based on the constraint conditions of predesigned seventh-order polynomial function curve and the theory of linear algebra, the polynomial coefficients of the seventh-order polynomial function of transmission error can be obtained. By applying a method named reverse tooth contact analysis, the modified roll coefficients as well as parts of machine-tool settings for the face-milling of spiral bevel gears can be individually determined. Therefore, a predesigned seventh-order polynomial function of transmission error for spiral bevel gears can be obtained by the modified roll with high-order coef- ficients, and comparisons of the seventh-order polynomial and parabolic functions of transmission error are also performed. The achievement of spiral bevel gears with the seventh-order function of transmission error can be accomplished on a universal Cartesian-type hypoid gear generator or a numerically controlled cradle-style hypoid gear generator due to its simple generating motion of axes of the cradle and the work piece. The results of a numerical example show that the bending stresses of the tooth of seventh-order are less than those of a parabolic one, while the contact stresses remain almost eouivalent. 相似文献
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叙述了适用于不同特性的螺旋齿面零件精密测量的两种典型的数学模型,进行比较研究并提出统一的接触几何模型. 相似文献
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Yang Su W.Q. GanY.P. Li 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(6):988-991
Based on the light curves and images of RHESSI flares, we tried to make a preliminary classification of solar flares. Three basic types of flares seem to be existed: accordantly gradual flares, accordantly impulsive flares, and early impulsive flares. The proportion for each type is given. The possible physical meaning related to different types is discussed. 相似文献