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定向凝固条件下Ti_(3)Al合金中梯度纳米结构的形成机制与力学行为——原子尺度研究
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作者 邹鹏飞 李昌 +5 位作者 侯兆阳 jia-yi sun 高全华 李克凡 王真 Ke-jun DONG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第5期1507-1519,共13页
通过分子动力学(MD)模拟方法对Ti_(3)Al合金在定向凝固条件下的生长机理进行系统研究,并通过对比纳米晶(NG)、粗晶(CG)和梯度纳米晶(GNG)合金,研究Ti_(3)Al合金的结构力学性能。结果表明,在凝固过程中Ti_(3)Al相优先生长为等轴晶组织,... 通过分子动力学(MD)模拟方法对Ti_(3)Al合金在定向凝固条件下的生长机理进行系统研究,并通过对比纳米晶(NG)、粗晶(CG)和梯度纳米晶(GNG)合金,研究Ti_(3)Al合金的结构力学性能。结果表明,在凝固过程中Ti_(3)Al相优先生长为等轴晶组织,随后逐渐演变为柱状粒,并最终形成梯度纳米晶结构。此时,晶粒在与凝固方向平行的方向优先生长。此外,研究还发现,相较于NG和CG结构,GNG结构定向凝固合金具有更高的抗拉强度和更好的延展性。GNG结构不仅有效抑制了小晶粒区域的应变局域化和晶粒生长,而且促进了较大晶粒区域的位错形成,从而获得更好的力学性能。 展开更多
关键词 定向凝固 Ti_(3)Al合金 分子动力学模拟 梯度纳米结构
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Association between cumulative blood pressure and long-term risk of cardiovascular disease: findings from the 26-year Chinese Multi-provincial Cohort Study-Beijing Project 被引量:1
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作者 Shuai Liu Dong Zhao +5 位作者 Miao Wang Yue Qi jia-yi sun Jun Liu Yan Li Jing Liu 《Chinese Medical Journal》 SCIE CAS CSCD 2021年第8期920-926,共7页
Background::Cumulative blood pressure(BP),a measure incorporating the level and duration of BP exposure,is associated with the risk of cardiovascular disease(CVD).However,the level at which cumulative BP could signifi... Background::Cumulative blood pressure(BP),a measure incorporating the level and duration of BP exposure,is associated with the risk of cardiovascular disease(CVD).However,the level at which cumulative BP could significantly increase the risk remains unclear.This study aimed to investigate the association of 15-year cumulative BP levels with the long-term risk of CVD,and to examine whether the association is independent of BP levels at one examination.Methods::Data from a 26-year follow-up of the Chinese Multi-provincial Cohort Study-Beijing Project were analyzed.Cumulative BP levels between 1992 and 2007 were calculated among 2429 participants free of CVD in 2007.Cardiovascular events(including coronary heart disease and stroke)occurring from 2007 to 2018 were registered.Adjusted hazard ratios(HRs)for CVD incidence associated with quartiles of cumulative systolic blood pressure(SBP)and diastolic blood pressure(DBP)were calculated.Results::Of the 2429 participants,42.9%(1042)were men,and the mean age in 2007 was 62.1±7.9 years.Totally,207 CVD events occurred during the follow-up from 2007 to 2018.Participants with higher levels of cumulative SBP or DBP exhibited a higher incidence rate of CVD(P<0.001).Compared with the lowest quartile of cumulative SBP,the HR for CVD was 1.03(95%confidence interval[CI]:0.59-1.81),1.69(95%CI:0.99-2.87),and 2.20(95%CI:1.21-3.98)for the second to the fourth quartile of cumulative SBP,and 1.46(95%CI:0.86-2.48),1.99(95%CI:1.18-3.35),and 2.08(95%CI:1.17-3.71)for the second to the fourth quartile of cumulative DBP,respectively.In further cross-combined group analyses with BP measurements in 2007,15-year cumulative BP levels higher than the median,that is,1970.8/1239.9 mmHg·year for cumulative SBP/DBP,which were equivalent to maintaining SBP/DBP levels of 131/83 mmHg or above on average in 15 years,were associated with higher risk of CVD in subsequent years independent of BP measurements at one-time point.Conclusion::Cumulative exposure to moderate elevation of BP is independently associated with increased future cardiovascular risk. 展开更多
关键词 Blood pressure Cardiovascular disease Cohort study
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