The kinetics of formation of crystal boron was studied by X-ray structure and differential-thermal analyses. The enthalpy of transition of amorphous boron to crystal boron with formation of an intermediate non-equilib...The kinetics of formation of crystal boron was studied by X-ray structure and differential-thermal analyses. The enthalpy of transition of amorphous boron to crystal boron with formation of an intermediate non-equilibrium phase was determined by the calorimetric method. Studies were carried out by using the differential scanning calorimeter SETARAM. Amorphous boron received by diboron cracking was used as the starting material. The test sample is cha- racterized by stability even at a high temperature. When heated, amorphous boron first transforms to crystal boron of α-modification, and during a further heating, there occur several phase transitions, which means the transition of α-rhombohedric crystal boron to the β'?and β''?metastable states. Studies of various modifications were carried out by radiographic and electro-optic methods. The high sensitiveness of the calorimeter made it possible to control temperature in the oven, make records and detect even the smallest thermal effects.展开更多
A new compoud based on carbazole functionalized β-diketone-boron difluoride(1) was synthesized.It is found that compoud 1 can gel toluene,ethylbenzene and some mixed solvents,and 3D networks consisting lots of nanofi...A new compoud based on carbazole functionalized β-diketone-boron difluoride(1) was synthesized.It is found that compoud 1 can gel toluene,ethylbenzene and some mixed solvents,and 3D networks consisting lots of nanofibers were observed using SEM and fluorescence microscopy.The molecular packing model in xerogel 1 was proposed according to the results of XRD,UV/Vis absorption and semiempirical calculations.The obtained nanofibers prepared through organogelation can emit strong orange light under irradiation.It is interesting that the fluorescence of the nanofiber-based film can be quenched quickly and significantly upon exposed to the vapors of n-butylamine,dibutylamine,triethylamine,triethylamine,cyclohexylamine,aniline and pyridine instead of other common reagents.Notably,the response time of the nanofiber-based film to aniline vapor reached ca.0.59 s,and the detection limit for aniline was as low as ca.0.83 mL/m 3.展开更多
文摘The kinetics of formation of crystal boron was studied by X-ray structure and differential-thermal analyses. The enthalpy of transition of amorphous boron to crystal boron with formation of an intermediate non-equilibrium phase was determined by the calorimetric method. Studies were carried out by using the differential scanning calorimeter SETARAM. Amorphous boron received by diboron cracking was used as the starting material. The test sample is cha- racterized by stability even at a high temperature. When heated, amorphous boron first transforms to crystal boron of α-modification, and during a further heating, there occur several phase transitions, which means the transition of α-rhombohedric crystal boron to the β'?and β''?metastable states. Studies of various modifications were carried out by radiographic and electro-optic methods. The high sensitiveness of the calorimeter made it possible to control temperature in the oven, make records and detect even the smallest thermal effects.
基金supported by the National Natural Science Foundation of China (51073068)the National Basic Research Program of China(2009CB939701)+1 种基金NSFC-JSPS Scientific Cooperation Program(21011140069)the Open Project of State Key Laboratory of Supramolecular Structure and Materials (SKLSSM201203)
文摘A new compoud based on carbazole functionalized β-diketone-boron difluoride(1) was synthesized.It is found that compoud 1 can gel toluene,ethylbenzene and some mixed solvents,and 3D networks consisting lots of nanofibers were observed using SEM and fluorescence microscopy.The molecular packing model in xerogel 1 was proposed according to the results of XRD,UV/Vis absorption and semiempirical calculations.The obtained nanofibers prepared through organogelation can emit strong orange light under irradiation.It is interesting that the fluorescence of the nanofiber-based film can be quenched quickly and significantly upon exposed to the vapors of n-butylamine,dibutylamine,triethylamine,triethylamine,cyclohexylamine,aniline and pyridine instead of other common reagents.Notably,the response time of the nanofiber-based film to aniline vapor reached ca.0.59 s,and the detection limit for aniline was as low as ca.0.83 mL/m 3.
