Filtration and cross-flow ultrafiltration techniques were used to separate culture media of Prorocentrurn donghaiense at the exponential growth, stationary and decline stages into 〈0.45 μm filtrate, 100 kDa-0.45 μm...Filtration and cross-flow ultrafiltration techniques were used to separate culture media of Prorocentrurn donghaiense at the exponential growth, stationary and decline stages into 〈0.45 μm filtrate, 100 kDa-0.45 μm, 1%100 kDa and 1-10 kDa retentate and 〈1 kDa ultrafiltrate fractions. The fluorescence properties of different molecular weights of dissolved organic matter （DOM） were measured by excitation-emission matrix spectra. Protein-like and humic-like fluorophores were observed in the DOM produced by P. donghaiense. The central positions of protein-like fluorophores showed a red shift with prolonged growth duration, shifting from tyrosine-like properties at the exponential growth stage to tryptophan-like properties at the stationary and decline stages. The excitation wavelengths of protein-like fluorophores exhibited some change in the exponential growth and stationary stages with increased molecular size, but showed little change in the decline stage. However, the emission wavelengths in the decline stage exhibited a blue shift. Very distinct C type and A type peaks in humic-like fluorophores were observed. With a prolonged culture time, the intensities of both of the peaks became strong and the excitation wavelengths of peak A showed a red shift, while the A：C ratios fell. More than 94% of fluorescent DOM was in the lower than 1 kDa molecular weight fraction.展开更多
Ultraviolet(UV)visualization has extensive applications in military and civil fields such as security monitoring,space communication,and wearable equipment for health monitoring in the internet of things(IoT).Due to t...Ultraviolet(UV)visualization has extensive applications in military and civil fields such as security monitoring,space communication,and wearable equipment for health monitoring in the internet of things(IoT).Due to their remarkable optoelectronic features,perovskite materials are regarded as promising candidates for UV light detecting and imaging.Herein,we report for the first time the excitationdependent perovskite/polymer films with dynamically tunable fluorescence ranging from green to magenta by changing the UV excitation from 260 to 380 nm.And they still render dynamic multicolor UV light imaging with different polymer matrixes,halogen ratios,and cations of perovskite materials.The mechanism of its fluorescence change is related to the chloride vacancies in perovskite materials.A patterned multi-color ultraviolet visualization pad is also demonstrated for visible conversion of the UV region.This technique may provide a universal strategy for information securities,UV visualizations,and dynamic multi-color displays in the IoT.展开更多
基金Supported by the High Technology Research and Development Program of China (863 Program) (Nos 2006AA09Z180 and 2004AA639790)the National Natural Science Foundation of China (No 40106013)the National Basic Research Program of China (973 Program) (No 2001CB409703)
文摘Filtration and cross-flow ultrafiltration techniques were used to separate culture media of Prorocentrurn donghaiense at the exponential growth, stationary and decline stages into 〈0.45 μm filtrate, 100 kDa-0.45 μm, 1%100 kDa and 1-10 kDa retentate and 〈1 kDa ultrafiltrate fractions. The fluorescence properties of different molecular weights of dissolved organic matter （DOM） were measured by excitation-emission matrix spectra. Protein-like and humic-like fluorophores were observed in the DOM produced by P. donghaiense. The central positions of protein-like fluorophores showed a red shift with prolonged growth duration, shifting from tyrosine-like properties at the exponential growth stage to tryptophan-like properties at the stationary and decline stages. The excitation wavelengths of protein-like fluorophores exhibited some change in the exponential growth and stationary stages with increased molecular size, but showed little change in the decline stage. However, the emission wavelengths in the decline stage exhibited a blue shift. Very distinct C type and A type peaks in humic-like fluorophores were observed. With a prolonged culture time, the intensities of both of the peaks became strong and the excitation wavelengths of peak A showed a red shift, while the A：C ratios fell. More than 94% of fluorescent DOM was in the lower than 1 kDa molecular weight fraction.
基金supported by the National Natural Science Foundation of China(52125205,11974317,11674290,U20A20166,U1704138,52192614,61805015,and 61804011)the National Key R&D Program of China(2021YFB3200302 and 2021YFB3200304)+5 种基金Natural Science Foundation of Beijing Municipality(Z180011 and 2222088)Shenzhen Science and Technology Program(KQTD20170810105439418)the Fundamental Research Funds for the Central UniversitiesHenan Science Fund for Distinguished Young Scholars(212300410020)Key Project of Henan Higher Education(21A140001)the Zhengzhou University Physics Discipline Improvement Program。
文摘Ultraviolet(UV)visualization has extensive applications in military and civil fields such as security monitoring,space communication,and wearable equipment for health monitoring in the internet of things(IoT).Due to their remarkable optoelectronic features,perovskite materials are regarded as promising candidates for UV light detecting and imaging.Herein,we report for the first time the excitationdependent perovskite/polymer films with dynamically tunable fluorescence ranging from green to magenta by changing the UV excitation from 260 to 380 nm.And they still render dynamic multicolor UV light imaging with different polymer matrixes,halogen ratios,and cations of perovskite materials.The mechanism of its fluorescence change is related to the chloride vacancies in perovskite materials.A patterned multi-color ultraviolet visualization pad is also demonstrated for visible conversion of the UV region.This technique may provide a universal strategy for information securities,UV visualizations,and dynamic multi-color displays in the IoT.
