The excited-state intramolecular proton transfer of 2-(2-hydroxyphenyl)benzoxazole dye in different solvents is investigated using ultrafast femtosecond transient absorption spectroscopy combined with quantum chemical...The excited-state intramolecular proton transfer of 2-(2-hydroxyphenyl)benzoxazole dye in different solvents is investigated using ultrafast femtosecond transient absorption spectroscopy combined with quantum chemical calculations.Conformational conversion from the syn-enol configuration to the keto configuration is proposed as the mechanism of excited-state intramolecular proton transfer.The duration of excited-state intramolecular proton transfer is measured to range from 50 fs to 200 fs in different solvents.This time is strongly dependent on the calculated energy gap between the N-S;and T-S;structures in the S;state.Along the proton transfer reaction coordinate,the vibrational relaxation process on the S;state potential surface is observed.The duration of the vibrational relaxation process is determined to be from8.7 ps to 35 ps dependent on the excess vibrational energy.展开更多
Castanopsis sclerophylla was surveyed for its root turion capacity on Laoshan Island in Zhejiang Pro- vince and dispersion patterns of seedlings, genetic diversity and genetic variation coefficient was studied using a...Castanopsis sclerophylla was surveyed for its root turion capacity on Laoshan Island in Zhejiang Pro- vince and dispersion patterns of seedlings, genetic diversity and genetic variation coefficient was studied using a SSR （simple sequence repeat） molecular marker technique to explore the genetic diversity of C. sclerophylla （Lindl.） Schott as a community and evaluate the community＇s development. The results showed that C. sclerophylla had strong root turion capacity, of which type Re2 was the most frequent, accounting for 32.4 and 82.4 % of the seedlings under the stock plant were from within-community mating; the 6 pairs of SSR primers chosen yielded high resolution with 97.6 % polymorphic sites; the within-community genetic diversity was over 88.9 % with stock plants （0.49） 〉 seedling plants （0.45）. Apparently, C. scerophyllan on Laoshan Island, propagating mainly by root tufions, has developed high genetic diversity within a short period, keeping the community in a stage of stable growth and moving toward a climax community. The tillers, however, aggravate closing of the community so that it receives less pollen from outside. Within-community mating is thus reaching seriously high levels, which can lead to lower within-community genetic variation, a decline in DNA genetic diversity, and is bad for its development. Therefore, human interference should be taken to expand genetic exchange among communities.展开更多
基金supported by the Natural Science Foundation of Hubei Province,China(Grant No.2020CFB468)the Guiding Project of Scientific Research Plan of Department of Education of Hubei Province,China(Grant No.B2020136)+1 种基金the National Key Research and Development Program of China(Grant No.2019YFA0307700)the National Natural Science Foundation of China(Grant Nos.11974381,11674355,and 21507027)。
文摘The excited-state intramolecular proton transfer of 2-(2-hydroxyphenyl)benzoxazole dye in different solvents is investigated using ultrafast femtosecond transient absorption spectroscopy combined with quantum chemical calculations.Conformational conversion from the syn-enol configuration to the keto configuration is proposed as the mechanism of excited-state intramolecular proton transfer.The duration of excited-state intramolecular proton transfer is measured to range from 50 fs to 200 fs in different solvents.This time is strongly dependent on the calculated energy gap between the N-S;and T-S;structures in the S;state.Along the proton transfer reaction coordinate,the vibrational relaxation process on the S;state potential surface is observed.The duration of the vibrational relaxation process is determined to be from8.7 ps to 35 ps dependent on the excess vibrational energy.
基金funded by the Key Project of Science and Technology Department of Zhejiang Province(2006C12059-3)National Natural Science and Technology Resources Platform Project of China(2006DKA21003-09)
文摘Castanopsis sclerophylla was surveyed for its root turion capacity on Laoshan Island in Zhejiang Pro- vince and dispersion patterns of seedlings, genetic diversity and genetic variation coefficient was studied using a SSR （simple sequence repeat） molecular marker technique to explore the genetic diversity of C. sclerophylla （Lindl.） Schott as a community and evaluate the community＇s development. The results showed that C. sclerophylla had strong root turion capacity, of which type Re2 was the most frequent, accounting for 32.4 and 82.4 % of the seedlings under the stock plant were from within-community mating; the 6 pairs of SSR primers chosen yielded high resolution with 97.6 % polymorphic sites; the within-community genetic diversity was over 88.9 % with stock plants （0.49） 〉 seedling plants （0.45）. Apparently, C. scerophyllan on Laoshan Island, propagating mainly by root tufions, has developed high genetic diversity within a short period, keeping the community in a stage of stable growth and moving toward a climax community. The tillers, however, aggravate closing of the community so that it receives less pollen from outside. Within-community mating is thus reaching seriously high levels, which can lead to lower within-community genetic variation, a decline in DNA genetic diversity, and is bad for its development. Therefore, human interference should be taken to expand genetic exchange among communities.
