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ARB过程中β钛基SMA显微结构演化及对其超弹性能的影响
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作者 蔡文昊 张德闯 +1 位作者 李理 林建国 《固体力学学报》 CAS CSCD 北大核心 2020年第3期223-230,共8页
论文采用复合轧制(Accumulative Roll-Bonding,ARB)工艺对β钛基形状记忆合金(SMA)进行轧制,然后700℃下快速热处理(保温5 min).利用光学显微镜(OM)和X射线衍射仪(XRD)对合金轧制热处理前后合金相组成与显微组织进行分析,并用电子万能... 论文采用复合轧制(Accumulative Roll-Bonding,ARB)工艺对β钛基形状记忆合金(SMA)进行轧制,然后700℃下快速热处理(保温5 min).利用光学显微镜(OM)和X射线衍射仪(XRD)对合金轧制热处理前后合金相组成与显微组织进行分析,并用电子万能试验机对轧制试样的力学性能和超弹性能进行测试.研究了β钛基形状记忆合金复合轧制过程中显微结构演化规律及对其超弹性能的影响.结果表明:复合轧制工艺能有效细化合金晶粒,经过轧制8道次、700℃/5 min快速热处理可得到全β相合金组织,其晶粒尺寸1μm;复合轧制处理后合金的超弹性能得到了改善,在预变形为6%时,其回复变形为5.94%,回复率为99%,表现出稳定的超弹性. 展开更多
关键词 ARB工艺 β钛基形状记忆合金 显微组织演化 超弹性
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Efficacy of early prone or lateral positioning in patients with severe COVID-19:a single-center prospective cohort
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作者 Zhong Ni Kaige Wang +18 位作者 Ting Wang Yuenan Ni Wei Huang Ping Zhu Tao Fan Ye Wang Bo Wang Jun Deng Zhicheng Qian Jiasheng Liu wenhao cai Shanling Xu Yu Du Gang Wang Zongan Liang Weimin Li Jianfei Luo Fengming Luo Dan Liu 《Precision Clinical Medicine》 2020年第4期260-271,共12页
Background:Position intervention has been shown to improve oxygenation,but its role in non-invasively ventilated patients with severe COVID-19 has not been assessed.The objective of this study was to investigate the e... Background:Position intervention has been shown to improve oxygenation,but its role in non-invasively ventilated patients with severe COVID-19 has not been assessed.The objective of this study was to investigate the efficacy of early position intervention on non-invasively ventilated patients with severe COVID-19.Methods:This was a single-center,prospective observational study in consecutive patients with severe COVID-19 managed in a provisional ICU at Renmin Hospital of Wuhan University from 31 January to 15 February 2020.Patients with chest CT showing exudation or consolidation in bilateral peripheral and posterior parts of the lungs were included.Early position intervention(prone or lateral)was commenced for>4 hours daily for 10 days in these patients,while others received standard care.Results:The baseline parameters were comparable between the position intervention group(n=17)and the standard care group(n=35).Position intervention was well-tolerated and increased cumulative adjusted mean difference of SpO_(2)/FiO_(2)(409,95%CI 86 to 733)and ROX index(26,95%CI 9 to 43)with decreased Borg scale(−9,95%CI−15 to−3)during the first 7 days.It also facilitated absorption of lung lesions and reduced the proportion of patients with high National Early Warning Score 2(≥7)on days 7 and 14,with a trend toward faster clinical improvement.Virus shedding and length of hospital stay were comparable between the two groups.Conclusions:This study provides the first evidence for improved oxygenation and lung lesion absorption using early position intervention in non-invasively ventilated patients with severe COVID-19,and warrants further randomized trials. 展开更多
关键词 COVID-19 early position intervention OXYGENATION ROX index Borg scale
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