Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-...Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-ray diffraction, N2 adsorption-desorption, Fourier-transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy, scanning electron microscopy, and ultraviolet-visible spectroscopy. The use of the colloidal seed reduced the crystal size, and an appropriate amount of silicalite-1 seed assisted Ti incorporation into the TS-1 framework. This method reduces the cost of TS- 1 synthesis because a significantly smaller amount of tetrapropylammonium hydroxide is used. The catalytic performance of the synthesized small-crystal TS-1 samples in cyclohexanone ammoximation was better than that of bulk TS-1 as a result of improved diffusion and a larger number of active tetrahedral Ti centers.展开更多
Small-molecule organic semiconductor crystals(SMOSCs) combine broadband light absorption(ultraviolet–visible–near infrared) with long exciton diffusion length and high charge carrier mobility. Therefore, they are pr...Small-molecule organic semiconductor crystals(SMOSCs) combine broadband light absorption(ultraviolet–visible–near infrared) with long exciton diffusion length and high charge carrier mobility. Therefore, they are promising candidates for realizing high-performance photodetectors. Here, after a brief resume of photodetector performance parameters and operation mechanisms, we review the recent advancements in application of SMOSCs as photodetectors, including photoconductors, phototransistors, and photodiodes. More importantly, the SMOSC-based photodetectors are further categorized according to their detection regions that cover a wide range from ultraviolet to near infrared. Finally, challenges and outlooks of SMOSC-based photodetectors are provided.展开更多
The large size of the crystallites in poly（L-lactide） and the low growth rate enable detailed time- and temperaturedependent X-ray scattering studies of the ordering processes to be carded out. A layer located inter...The large size of the crystallites in poly（L-lactide） and the low growth rate enable detailed time- and temperaturedependent X-ray scattering studies of the ordering processes to be carded out. A layer located intermediate between crystals and melt-like regions is observed which finally takes on crystalline order. Recrystallization processes during heating change the complete stack structure rather than the crystallites individually and produce voids in the stacks, Establishment of a new stable structure after a temperature jump in the melting range can be followed in time. DSC experiments indicate times of melting of the order of minutes.展开更多
基金supported by the National Natural Science Foundation of China(21403070 and 21373088)Innovation Program of Shanghai Municipal Education Commission(13zz038)+2 种基金Key Project of the Shanghai Committee of Science and Technology(12JC1403600)National Key Technology R&D Program(2012BAE05B02)Shanghai Leading Academic Discipline Project(B409)~~
文摘Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-ray diffraction, N2 adsorption-desorption, Fourier-transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy, scanning electron microscopy, and ultraviolet-visible spectroscopy. The use of the colloidal seed reduced the crystal size, and an appropriate amount of silicalite-1 seed assisted Ti incorporation into the TS-1 framework. This method reduces the cost of TS- 1 synthesis because a significantly smaller amount of tetrapropylammonium hydroxide is used. The catalytic performance of the synthesized small-crystal TS-1 samples in cyclohexanone ammoximation was better than that of bulk TS-1 as a result of improved diffusion and a larger number of active tetrahedral Ti centers.
基金supported by the National Natural Science Foundation of China(Grant Nos.51672180,51622306,and 21673151)Collaborative Innovation Center of Suzhou Nano Science&Technology+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the 111 Project,Joint International Research Laboratory of Carbon-Based Functional Materials and Devices
文摘Small-molecule organic semiconductor crystals(SMOSCs) combine broadband light absorption(ultraviolet–visible–near infrared) with long exciton diffusion length and high charge carrier mobility. Therefore, they are promising candidates for realizing high-performance photodetectors. Here, after a brief resume of photodetector performance parameters and operation mechanisms, we review the recent advancements in application of SMOSCs as photodetectors, including photoconductors, phototransistors, and photodiodes. More importantly, the SMOSC-based photodetectors are further categorized according to their detection regions that cover a wide range from ultraviolet to near infrared. Finally, challenges and outlooks of SMOSC-based photodetectors are provided.
基金This work was supported by the Deutsche Forschungsgemeinschaft. Thanks are also due to the Fonds der Chemischen Industrie for financial help.
文摘The large size of the crystallites in poly（L-lactide） and the low growth rate enable detailed time- and temperaturedependent X-ray scattering studies of the ordering processes to be carded out. A layer located intermediate between crystals and melt-like regions is observed which finally takes on crystalline order. Recrystallization processes during heating change the complete stack structure rather than the crystallites individually and produce voids in the stacks, Establishment of a new stable structure after a temperature jump in the melting range can be followed in time. DSC experiments indicate times of melting of the order of minutes.
