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31.
随着高职高专校园文化生活、人文生活的日益丰富多彩,大学生们对休闲体育这一娱乐性较强的锻炼方式呼声也越来越强。本文旨在为相关院校深化体育课程改革和开展休闲体育提供参考。 相似文献
32.
Effect of continuous annealing temperature on microstructure and properties of ferritic rolled interstitial-free steel
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Chen-yang Qiu Lang Li Lei-lei Hao Jian-gong Wang Xun Zhou Yong-lin Kang 《矿物冶金与材料学报》2018,25(5):536-546
In this report, the microstructure, mechanical properties, and textures of warm rolled interstitial-free steel annealed at four different temperatures (730, 760, 790, and 820℃) were studied. The overall structural features of specimens were investigated by optical microscopy, and the textures were measured by X-ray diffraction (XRD). Nano-sized precipitates were then observed by a transmission electron microscope (TEM) on carbon extraction replicas. According to the results, with increased annealing temperatures, the ferrite grains grew; in addition, the sizes of Ti4C2S2 and TiC precipitates also increased. Additionally, the sizes of TiN and TiS precipitates slightly changed. When the annealing temperature increased from 730 to 820℃, the yield strength (YS) and the ultimate tensile strength (UTS) showed a decreasing trend. Meanwhile, elongation and the strain harden exponent (n value) increased to 49.6% and 0.34, respectively. By comparing textures annealed at different temperatures, the intensity of {111} texture annealed at 820℃ was the largest, while the difference between the intensity of {111}<110> and {111}<112> was the smallest when the annealing temperature was 820℃. Therefore, the plastic strain ratio (r value) annealed at 820℃ was the highest. 相似文献
33.
Longzhi Li Yue Deng Kunkun Hu Bangqiang Xu Nana Wang Zhongchao Bai Xun Xu Jian Yang 《自然科学进展(英文版)》2023,33(1):16-36
Lithium-ion batteries have long been used in electronic products and electric vehicles, but their energy density is slowly failing to keep up with demand. Because of its extraordinarily high theoretical specific capacity, silicon is regarded as the most potential next-generation anode material for practical lithium-ion batteries. However, its unavoidable volume expansion issue can cause electrode deformation and loss of electrical contact during cycling,resulting in significant performance reduc... 相似文献