A time-resolved x-ray diffraction technique is employed to monitor the structural transformation of laser-shocked bismuth.Results reveal a retarded transformation from the shock-induced Bi-Ⅴphase to a metastable Bi-...A time-resolved x-ray diffraction technique is employed to monitor the structural transformation of laser-shocked bismuth.Results reveal a retarded transformation from the shock-induced Bi-Ⅴphase to a metastable Bi-Ⅳphase during the shock release,instead of the thermodynamically stable Bi-Ⅲphase.The emergence of the metastable Bi-Ⅳphase is understood by the competitive interplay between two transformation pathways towards the Bi-Ⅳand Bi-Ⅲ,respectively.The former is more rapid than the latter because the Bi-Ⅴto B-Ⅳtransformation is driven by interaction between the closest atoms while the Bi-Ⅴto B-Ⅲtransformation requires interaction between the second-closest atoms.The nucleation time for the Bi-Ⅴto Bi-Ⅳtransformation is determined to be 5.1±0.9 ns according to a classical nucleation model.This observation demonstrates the importance of the formation of the transient metastable phases,which can change the phase transformation pathway in a dynamic process.展开更多
为减轻盐胁迫对植物造成的伤害,本研究采用He-Ne激光对盐胁迫下的水稻进行辐照处理,选用水稻9311作为对照、耐盐海稻86作为研究对象,以0.5%的氯化钠进行盐胁迫,He-Ne激光(辐照计量5 m W·mm-2,波长632.8 nm)进行照射。设置了对照组(...为减轻盐胁迫对植物造成的伤害,本研究采用He-Ne激光对盐胁迫下的水稻进行辐照处理,选用水稻9311作为对照、耐盐海稻86作为研究对象,以0.5%的氯化钠进行盐胁迫,He-Ne激光(辐照计量5 m W·mm-2,波长632.8 nm)进行照射。设置了对照组(CK),盐胁迫组、盐胁迫和激光复合处理组(分别为L、BL组),进行了水稻抗氧化活性方面的研究。结果表明:与对照组(CK)比较,He-Ne激光对水稻的盐胁迫有一定的缓解作用,其中对水稻9311的作用最明显,表现为激光处理提高了水稻幼苗中过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活性和减缓了丙二醛(MDA)含量的增速;同时也说明新选育的海稻86耐盐性高于水稻9311。因此,一定剂量的He-Ne激光可以提高了水稻的耐盐性,这为抗盐胁迫及耐盐植物的育种提供了途径和理论依据。展开更多
基金supported by the National Natural Science Foundation of China (Grant No.12072331)the Science Challenge Project (Grant No.TZ2018001)+2 种基金the Japan Society for the Promotion of Science (Grant Nos.17H04820 and 21H01677)the Foundation of the United Laboratory of High-Pressure Physics and Earthquake Scienceperformed under the approval of the Photon Factory Program Advisory Committee (Proposal Nos.2016S2-006 and 2020G680)。
文摘A time-resolved x-ray diffraction technique is employed to monitor the structural transformation of laser-shocked bismuth.Results reveal a retarded transformation from the shock-induced Bi-Ⅴphase to a metastable Bi-Ⅳphase during the shock release,instead of the thermodynamically stable Bi-Ⅲphase.The emergence of the metastable Bi-Ⅳphase is understood by the competitive interplay between two transformation pathways towards the Bi-Ⅳand Bi-Ⅲ,respectively.The former is more rapid than the latter because the Bi-Ⅴto B-Ⅳtransformation is driven by interaction between the closest atoms while the Bi-Ⅴto B-Ⅲtransformation requires interaction between the second-closest atoms.The nucleation time for the Bi-Ⅴto Bi-Ⅳtransformation is determined to be 5.1±0.9 ns according to a classical nucleation model.This observation demonstrates the importance of the formation of the transient metastable phases,which can change the phase transformation pathway in a dynamic process.
文摘为减轻盐胁迫对植物造成的伤害,本研究采用He-Ne激光对盐胁迫下的水稻进行辐照处理,选用水稻9311作为对照、耐盐海稻86作为研究对象,以0.5%的氯化钠进行盐胁迫,He-Ne激光(辐照计量5 m W·mm-2,波长632.8 nm)进行照射。设置了对照组(CK),盐胁迫组、盐胁迫和激光复合处理组(分别为L、BL组),进行了水稻抗氧化活性方面的研究。结果表明:与对照组(CK)比较,He-Ne激光对水稻的盐胁迫有一定的缓解作用,其中对水稻9311的作用最明显,表现为激光处理提高了水稻幼苗中过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活性和减缓了丙二醛(MDA)含量的增速;同时也说明新选育的海稻86耐盐性高于水稻9311。因此,一定剂量的He-Ne激光可以提高了水稻的耐盐性,这为抗盐胁迫及耐盐植物的育种提供了途径和理论依据。
