The well crystalline YAG：Ce^3＋ phosphor was synthesized by sold-state method, and the temperature dependence of excitation and emission spectra of YAG：Ce^3＋ phosphor were investigated in the temperature range from...The well crystalline YAG：Ce^3＋ phosphor was synthesized by sold-state method, and the temperature dependence of excitation and emission spectra of YAG：Ce^3＋ phosphor were investigated in the temperature range from room temperature to 573 K. With temperature increasing, it was noted that the emission intensity of as-repared phosphors decreased considerably more rapidly when pumped by 460 nm than by 340 nm. The temperature-intensity curves under different excitation wavelengths were obtained using an Arrhenius function, and the corresponding activation energies were also obtained respectively. Thus, the experimental phenomenon was discussed in terms of nonradiative decay rate. The effects of as-prepared phosphors on the performance of the white LED with changing temperature were also studied.展开更多
A series of aAl5O12：Ce （YAG：Ce） phosphors doped with different Si4＋ concentrations is prepared by solid-state reaction. The temperature dependent characteristics of luminescent spectrum and decay time of Ce3＋ ar...A series of aAl5O12：Ce （YAG：Ce） phosphors doped with different Si4＋ concentrations is prepared by solid-state reaction. The temperature dependent characteristics of luminescent spectrum and decay time of Ce3＋ are investigated. With Si4＋ doped, the emission spectrum shows a blue shift clue to a decrease of the splitting of 5d levels of Ce3＋ ion. The thermal stability is greatly improved by adding Si4＋ because the activation energy AE increases from 0.1836 eV to 0.2401 eV. The study of the decay times against temperature for various doping concentrations of Si4＋ shows that the calculated nonradiative decay rate is affected by Si4＋ substitution. The results are explained by the configurational coordinate diagram.展开更多
Henry Pratt公司生产的大尺寸蝶阀在中核核电运行管理有限公司三厂海水系统中被大量使用,由于杭州湾地区海水泥沙含量高,机组运行工况恶劣,投运10年后,部分蝶阀已经开始出现填料函泄漏、阀座和阀板密封圈磨损、阀板衬胶脱落、阀板腐蚀...Henry Pratt公司生产的大尺寸蝶阀在中核核电运行管理有限公司三厂海水系统中被大量使用,由于杭州湾地区海水泥沙含量高,机组运行工况恶劣,投运10年后,部分蝶阀已经开始出现填料函泄漏、阀座和阀板密封圈磨损、阀板衬胶脱落、阀板腐蚀、阀板销钉磨损或脱落等问题。文中介绍了填料函泄漏和阀门内漏故障分析及修复处理的方法。展开更多
乳腺癌已成为女性最常见的恶性肿瘤[1]。2008年,全球女性新发乳腺癌138万例,占女性恶性肿瘤患者的22.9%,死亡46万例,占女性恶性肿瘤死亡患者的13.7%[2]。美国癌症协会（American Cancer Society,ACS）每年推出一份统计报告预估全美在未...乳腺癌已成为女性最常见的恶性肿瘤[1]。2008年,全球女性新发乳腺癌138万例,占女性恶性肿瘤患者的22.9%,死亡46万例,占女性恶性肿瘤死亡患者的13.7%[2]。美国癌症协会（American Cancer Society,ACS）每年推出一份统计报告预估全美在未来一年的新发乳腺癌症病例以及因乳腺癌死亡的人数,预计2013年将有大约296 980例新发乳腺癌病例被确诊,因乳腺癌死亡的美国妇女将达到39 620人。展开更多
基金the Key Technologies R&D Program of Shandong Province (2006gg2201014)Tianjin Natural Science Foundation (07JCYBJC06400)Tianjin Education Committee Science and Technology Development Foundation
文摘The well crystalline YAG：Ce^3＋ phosphor was synthesized by sold-state method, and the temperature dependence of excitation and emission spectra of YAG：Ce^3＋ phosphor were investigated in the temperature range from room temperature to 573 K. With temperature increasing, it was noted that the emission intensity of as-repared phosphors decreased considerably more rapidly when pumped by 460 nm than by 340 nm. The temperature-intensity curves under different excitation wavelengths were obtained using an Arrhenius function, and the corresponding activation energies were also obtained respectively. Thus, the experimental phenomenon was discussed in terms of nonradiative decay rate. The effects of as-prepared phosphors on the performance of the white LED with changing temperature were also studied.
基金supported by the National Basic Research Program of China (Grant No. 6139702)the National Natural Science Foundation of China (Grant Nos. 60877029,60977035 and 60907021)+1 种基金the Natural Science Foundation of the Tianjin Education Committee,China (Grant No. 20071207)the Natural Science Foundation of Tianjin,China (Grant Nos. 09JCYBJC01400and 07JCYBJC06400)
文摘A series of aAl5O12：Ce （YAG：Ce） phosphors doped with different Si4＋ concentrations is prepared by solid-state reaction. The temperature dependent characteristics of luminescent spectrum and decay time of Ce3＋ are investigated. With Si4＋ doped, the emission spectrum shows a blue shift clue to a decrease of the splitting of 5d levels of Ce3＋ ion. The thermal stability is greatly improved by adding Si4＋ because the activation energy AE increases from 0.1836 eV to 0.2401 eV. The study of the decay times against temperature for various doping concentrations of Si4＋ shows that the calculated nonradiative decay rate is affected by Si4＋ substitution. The results are explained by the configurational coordinate diagram.
文摘乳腺癌已成为女性最常见的恶性肿瘤[1]。2008年,全球女性新发乳腺癌138万例,占女性恶性肿瘤患者的22.9%,死亡46万例,占女性恶性肿瘤死亡患者的13.7%[2]。美国癌症协会（American Cancer Society,ACS）每年推出一份统计报告预估全美在未来一年的新发乳腺癌症病例以及因乳腺癌死亡的人数,预计2013年将有大约296 980例新发乳腺癌病例被确诊,因乳腺癌死亡的美国妇女将达到39 620人。
