A real high power vacuum ultraviolet light source is applied to the investigation on the vacuum ultraviolet irra- diation degradation of BaMgAl10O17：Eu2＋ phosphor. The degradations of emission intensity and color qu...A real high power vacuum ultraviolet light source is applied to the investigation on the vacuum ultraviolet irra- diation degradation of BaMgAl10O17：Eu2＋ phosphor. The degradations of emission intensity and color quality of the sample are clearly observed after irradiation. It reveals that the oxidation of Eu2＋ during irradiation is partly respon- sible for the degradations. The excitation and absorption spectra show that some traps generated during irradiation have negative influence on the luminescence of sample and these traps have been identified as positively charged oxygen vacancies by positron annihilation. The investigations on host emission and decay curve further confirm that these oxygen vacancies are involved in the perturbation of energy transfer from the host to Eu2＋ and finally result in the degradation.展开更多
Original chitosan with M-v of 2.7 x 10(5) was degraded by irradiation with gamma-rays and a series of low molecular weight O-carboxymethylated chitosans (O-CMCh) were prepared based on the irradiated chitosan. A kinet...Original chitosan with M-v of 2.7 x 10(5) was degraded by irradiation with gamma-rays and a series of low molecular weight O-carboxymethylated chitosans (O-CMCh) were prepared based on the irradiated chitosan. A kinetic model of the irradiation of chitosan was put forward. Results show that the irradiation degradation of chitosan obeys the rule of random degradation and the degree of deacetylation of irradiated chitosan is slightly raised. The antibacterial activity of O-CMCh is significantly influenced by its MW, and a suppositional antibacterial peak appears when M-v is equal to 2 x 10(5).展开更多
基金Project supported by the National Natural Science Young Foundation of China(Grant No.10904057)the Fundamental Research Funds for Central Universities,China(Grant No.Lzjbky-2011-125)
文摘A real high power vacuum ultraviolet light source is applied to the investigation on the vacuum ultraviolet irra- diation degradation of BaMgAl10O17：Eu2＋ phosphor. The degradations of emission intensity and color quality of the sample are clearly observed after irradiation. It reveals that the oxidation of Eu2＋ during irradiation is partly respon- sible for the degradations. The excitation and absorption spectra show that some traps generated during irradiation have negative influence on the luminescence of sample and these traps have been identified as positively charged oxygen vacancies by positron annihilation. The investigations on host emission and decay curve further confirm that these oxygen vacancies are involved in the perturbation of energy transfer from the host to Eu2＋ and finally result in the degradation.
基金This work was supported by the National Natural Science Foundation of China (No. 50173019).
文摘Original chitosan with M-v of 2.7 x 10(5) was degraded by irradiation with gamma-rays and a series of low molecular weight O-carboxymethylated chitosans (O-CMCh) were prepared based on the irradiated chitosan. A kinetic model of the irradiation of chitosan was put forward. Results show that the irradiation degradation of chitosan obeys the rule of random degradation and the degree of deacetylation of irradiated chitosan is slightly raised. The antibacterial activity of O-CMCh is significantly influenced by its MW, and a suppositional antibacterial peak appears when M-v is equal to 2 x 10(5).
