The complex fluoride LiBaF3 is solvothermally synthesized at 180degreesC and characterized by means of X-ray powder diffraction, scanning electron microscopy, thermogravimetric analysis and infrared spectroscopy. In t...The complex fluoride LiBaF3 is solvothermally synthesized at 180degreesC and characterized by means of X-ray powder diffraction, scanning electron microscopy, thermogravimetric analysis and infrared spectroscopy. In the solvothermal process, the solvents, mole ratios of initial mixtures and reaction temperature play important roles in the growth of the single crystal.展开更多
KMgF3 doped with Eu was synthesized by mild hydrothermal method at 240C for the first time. The excitation and emission spectra of the KMgF3 : Eu2+ phosphor were measured. Comparing with the sample synthesized throu...KMgF3 doped with Eu was synthesized by mild hydrothermal method at 240C for the first time. The excitation and emission spectra of the KMgF3 : Eu2+ phosphor were measured. Comparing with the sample synthesized through solid state reaction, the variation in the excitation spectra at 360 nm resulted from the existences of VK color centers; the low emission intensity was due to Eu2+ having transferred part energy to VK color centers.展开更多
Quasi-Newton, fully-connected, and feed forward neural network were used to study the correlation between the spectral structure of the Eu2+ ion in complex fluorides and the structures of complex fluorides. The experi...Quasi-Newton, fully-connected, and feed forward neural network were used to study the correlation between the spectral structure of the Eu2+ ion in complex fluorides and the structures of complex fluorides. The experimental results show that the neural network architecture (number of layers and number of nodes in each layer),the intial weights. and the organization of the data were all important factors affecting the performance of the neural network. The performance of the neural network was enhanced by adapting a test set to monitor the training process. Once trained, the neural network correctly classified 100% of the training set and 96.3% of the test set. These results offer tremendous improvement over previous pattern recognition methods.展开更多
The complex fluoride α′ SrAlF 5 has been synthesized through hydrothermal and solvothermal methods under mild conditions. The effects of the molar ratio of starting materials, temperature, reaction time and solven...The complex fluoride α′ SrAlF 5 has been synthesized through hydrothermal and solvothermal methods under mild conditions. The effects of the molar ratio of starting materials, temperature, reaction time and solvents on the synthesis of α′ SrAlF 5 were discussed. The final products were characterized by XRD and SEM. The rod like shape of α′ SrAlF 5 is shown in SEM images.展开更多
The phosphors of ABF_4:Eu^(2+)and A_2SiF_6:Eu^(2+)(A=Na,K,Rb,Cs)have been synthesized,and the crystallographic data obtained accord with ASTM.In these materials,the f→f sharp lines emissions of Eu^(2+) were observed....The phosphors of ABF_4:Eu^(2+)and A_2SiF_6:Eu^(2+)(A=Na,K,Rb,Cs)have been synthesized,and the crystallographic data obtained accord with ASTM.In these materials,the f→f sharp lines emissions of Eu^(2+) were observed.The coordination numbers of Eu^(2+)in both NaBF_4 and Na_2SiF_6 hosts are less than 8.展开更多
Eu<sup>2+</sup> and Ce<sup>3+</sup> are important rare earth ions with variable valences. There existtwo kind of transition emission, d-f and f-f for Eu<sup>2+</sup>. Eu<sup>2...Eu<sup>2+</sup> and Ce<sup>3+</sup> are important rare earth ions with variable valences. There existtwo kind of transition emission, d-f and f-f for Eu<sup>2+</sup>. Eu<sup>2+</sup> is a good candidatefor the activators of UV-visible tunable laser and luminescent materials due to itstransition characteristics. Ce<sup>3+</sup> displays only d-f transition, which is different fromother rare earth ions. Because of the transition properties of Eu<sup>2+</sup> and Ce<sup>3+</sup>, theyare used both as good activators and as efficient sensitizers. Spectral展开更多
基金This work was supported by the State Key Project of Foundation Research (G1998061306) theNational Natural Science Foundation of China (50072031).
文摘The complex fluoride LiBaF3 is solvothermally synthesized at 180degreesC and characterized by means of X-ray powder diffraction, scanning electron microscopy, thermogravimetric analysis and infrared spectroscopy. In the solvothermal process, the solvents, mole ratios of initial mixtures and reaction temperature play important roles in the growth of the single crystal.
文摘KMgF3 doped with Eu was synthesized by mild hydrothermal method at 240C for the first time. The excitation and emission spectra of the KMgF3 : Eu2+ phosphor were measured. Comparing with the sample synthesized through solid state reaction, the variation in the excitation spectra at 360 nm resulted from the existences of VK color centers; the low emission intensity was due to Eu2+ having transferred part energy to VK color centers.
文摘Quasi-Newton, fully-connected, and feed forward neural network were used to study the correlation between the spectral structure of the Eu2+ ion in complex fluorides and the structures of complex fluorides. The experimental results show that the neural network architecture (number of layers and number of nodes in each layer),the intial weights. and the organization of the data were all important factors affecting the performance of the neural network. The performance of the neural network was enhanced by adapting a test set to monitor the training process. Once trained, the neural network correctly classified 100% of the training set and 96.3% of the test set. These results offer tremendous improvement over previous pattern recognition methods.
基金theMajorStateBasicResearchDevelopmentProgram (No .G19980 613 0 6)
文摘The complex fluoride α′ SrAlF 5 has been synthesized through hydrothermal and solvothermal methods under mild conditions. The effects of the molar ratio of starting materials, temperature, reaction time and solvents on the synthesis of α′ SrAlF 5 were discussed. The final products were characterized by XRD and SEM. The rod like shape of α′ SrAlF 5 is shown in SEM images.
基金Project supported by the National Natural Science Foundation of China.
文摘The phosphors of ABF_4:Eu^(2+)and A_2SiF_6:Eu^(2+)(A=Na,K,Rb,Cs)have been synthesized,and the crystallographic data obtained accord with ASTM.In these materials,the f→f sharp lines emissions of Eu^(2+) were observed.The coordination numbers of Eu^(2+)in both NaBF_4 and Na_2SiF_6 hosts are less than 8.
文摘Eu<sup>2+</sup> and Ce<sup>3+</sup> are important rare earth ions with variable valences. There existtwo kind of transition emission, d-f and f-f for Eu<sup>2+</sup>. Eu<sup>2+</sup> is a good candidatefor the activators of UV-visible tunable laser and luminescent materials due to itstransition characteristics. Ce<sup>3+</sup> displays only d-f transition, which is different fromother rare earth ions. Because of the transition properties of Eu<sup>2+</sup> and Ce<sup>3+</sup>, theyare used both as good activators and as efficient sensitizers. Spectral
