The Ba3Y2（BO3）4：Eu^3＋ phosphor was synthesized using a high temperature solid-state reaction method and the luminescent characteristics were investigated. The emission spectrum exhibited one strong red emission at...The Ba3Y2（BO3）4：Eu^3＋ phosphor was synthesized using a high temperature solid-state reaction method and the luminescent characteristics were investigated. The emission spectrum exhibited one strong red emission at 613 nm, corresponding to the electric dipole 5D0-TF2 transition of Eu^3＋, under 365 nm excitation. The excitation spectrum of 613 nm indicated that the Ba3Y2（BO3）n：Eu^3＋ phosphor was effectively excited by ultraviolet （UV） （254, 365 and 400 nm） and blue （470 nm） light. The effect of Eu^3＋ concentration on the 613 nm emission of the Ba3Y2（BO3）n：Eu^3＋ phosphor was measured. The results showed that the emission intensity increased with increasing Eu^3＋ concentration, and then decreased. The CIE color coordinates of Ba3Y2（BO3）4：Eu^3＋ phosphor were x=0.641 and y=0.359 at 15 mol.% Eu^3＋.展开更多
Top seeded infiltration and growth technique (TSIG) is an effective method for the preparation of high quality large YBa2Cu3O7-x (YBCO) bulk superconductors. In this paper, single domain YBCO bulk superconductors, wit...Top seeded infiltration and growth technique (TSIG) is an effective method for the preparation of high quality large YBa2Cu3O7-x (YBCO) bulk superconductors. In this paper, single domain YBCO bulk superconductors, with different Y2Ba4CuWOy (YW2411) additions, have been fabricated by TSIG process. the solid phase pellet is made of a mixture of Y2BaCuO5(Y211) + xwt% YW2411 powders, x=0, 1, 3, 5, 7, 9. The growth morphology, microstructure and levitation force of the YBCO bulks have been investigated, it is found that the levitation force is increasing from 23.05 to 33.6 N with the increasing of YW2411 addition from 0 to 5wt%, and decreasing from 33.6 to 21.59 N with the increasing of YW2411 addition from 5 to 9wt%,the largest levitation force is obtained when the YW2411 content is about 5wt%. This is very important for us to fabricate high quality YBCO bulk superconductors.展开更多
介绍了低介质常数εr 微波介质陶瓷中复合钙钛矿 Ba(X ,Y) O3系、(Zn,Sn) Ti O4系和 Ba O- Ti O2 系材料的结构和介电特性 ,分析其介电性质随结构和工艺参数的变化规律。以上系列微波介质陶瓷的烧结温度普遍较高 ,传统的介电理论不能完...介绍了低介质常数εr 微波介质陶瓷中复合钙钛矿 Ba(X ,Y) O3系、(Zn,Sn) Ti O4系和 Ba O- Ti O2 系材料的结构和介电特性 ,分析其介电性质随结构和工艺参数的变化规律。以上系列微波介质陶瓷的烧结温度普遍较高 ,传统的介电理论不能完全解释这些材料的损耗机制。今后的发展趋势是利用复合效应来得到εr更高 ,品质因数Q值更高 。展开更多
基金Project supported by the Hebei Provincial Technology Development Foundation (51215103b)Science Foundation of Hebei University (2006Q06)
文摘The Ba3Y2（BO3）4：Eu^3＋ phosphor was synthesized using a high temperature solid-state reaction method and the luminescent characteristics were investigated. The emission spectrum exhibited one strong red emission at 613 nm, corresponding to the electric dipole 5D0-TF2 transition of Eu^3＋, under 365 nm excitation. The excitation spectrum of 613 nm indicated that the Ba3Y2（BO3）n：Eu^3＋ phosphor was effectively excited by ultraviolet （UV） （254, 365 and 400 nm） and blue （470 nm） light. The effect of Eu^3＋ concentration on the 613 nm emission of the Ba3Y2（BO3）n：Eu^3＋ phosphor was measured. The results showed that the emission intensity increased with increasing Eu^3＋ concentration, and then decreased. The CIE color coordinates of Ba3Y2（BO3）4：Eu^3＋ phosphor were x=0.641 and y=0.359 at 15 mol.% Eu^3＋.
基金National Natural Science Foundation of China (51033026, 50872079)National High Technology Research and Development Program of China("863" Program, 2007AA03Z241)Fundamental Research Funds for the Central Universities (GK200901017)
文摘Top seeded infiltration and growth technique (TSIG) is an effective method for the preparation of high quality large YBa2Cu3O7-x (YBCO) bulk superconductors. In this paper, single domain YBCO bulk superconductors, with different Y2Ba4CuWOy (YW2411) additions, have been fabricated by TSIG process. the solid phase pellet is made of a mixture of Y2BaCuO5(Y211) + xwt% YW2411 powders, x=0, 1, 3, 5, 7, 9. The growth morphology, microstructure and levitation force of the YBCO bulks have been investigated, it is found that the levitation force is increasing from 23.05 to 33.6 N with the increasing of YW2411 addition from 0 to 5wt%, and decreasing from 33.6 to 21.59 N with the increasing of YW2411 addition from 5 to 9wt%,the largest levitation force is obtained when the YW2411 content is about 5wt%. This is very important for us to fabricate high quality YBCO bulk superconductors.
