Two-photon fluorescence dyes have shown promising applications in biomedical imaging.However,the substitution site effect on geometric structures and photophysical properties of fluorescence dyes is rarely illustrated...Two-photon fluorescence dyes have shown promising applications in biomedical imaging.However,the substitution site effect on geometric structures and photophysical properties of fluorescence dyes is rarely illustrated in detail.In this work,a series of new lipid droplets detection dyes are designed and studied,molecular optical properties and non-radiative transitions are analyzed.The intramolecular weak interaction and electron-hole analysis reveal its inner mechanisms.All dyes are proven to possess excellent photophysical properties with high fluorescence quantum efficiency and large stokes shift as well as remarkable two-photon absorption cross section.Our work reasonably elucidates the experimental measurements and the effects of substitution site on two-photon absorption and excited states properties of lipid droplets detection NAPBr dyes are highlighted,which could provide a theoretical perspective for designing efficient organic dyes for lipid droplets detection in biology and medicine fields.展开更多
The results of an experiment on discharges in long atmospheric pressure air gaps at a pulsed voltage of amplitude up to 800 kV and risetime 150-200 ns are analyzed. In the experiment, a radiation pulse of photon ener...The results of an experiment on discharges in long atmospheric pressure air gaps at a pulsed voltage of amplitude up to 800 kV and risetime 150-200 ns are analyzed. In the experiment, a radiation pulse of photon energy 〉 5 keV and duration 10-20 ns has been detected. It has been shown that the x-ray pulse is due to the ＂runaway＂ of electrons from the head of an anode-directed streamer. The estimated maximum bremsstrahlung energy is about 5-10 keV. The presence of a maximum in the bremsstrahlung spectrum is due to that the photons emitted by electrons are absorbed by atoms of the gas in which the discharge operates.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.11804196 and No.11904210)the Project funded by China Postdoctoral Science Foundation(No.2018M642689)the Open Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates,(South China University of Technology)(No.2019B030301003).
文摘Two-photon fluorescence dyes have shown promising applications in biomedical imaging.However,the substitution site effect on geometric structures and photophysical properties of fluorescence dyes is rarely illustrated in detail.In this work,a series of new lipid droplets detection dyes are designed and studied,molecular optical properties and non-radiative transitions are analyzed.The intramolecular weak interaction and electron-hole analysis reveal its inner mechanisms.All dyes are proven to possess excellent photophysical properties with high fluorescence quantum efficiency and large stokes shift as well as remarkable two-photon absorption cross section.Our work reasonably elucidates the experimental measurements and the effects of substitution site on two-photon absorption and excited states properties of lipid droplets detection NAPBr dyes are highlighted,which could provide a theoretical perspective for designing efficient organic dyes for lipid droplets detection in biology and medicine fields.
文摘The results of an experiment on discharges in long atmospheric pressure air gaps at a pulsed voltage of amplitude up to 800 kV and risetime 150-200 ns are analyzed. In the experiment, a radiation pulse of photon energy 〉 5 keV and duration 10-20 ns has been detected. It has been shown that the x-ray pulse is due to the ＂runaway＂ of electrons from the head of an anode-directed streamer. The estimated maximum bremsstrahlung energy is about 5-10 keV. The presence of a maximum in the bremsstrahlung spectrum is due to that the photons emitted by electrons are absorbed by atoms of the gas in which the discharge operates.
