A series of new red-emitting BaCa1–2xBO3F：xEu3＋, xM＋ （M=Li, Na, K） phosphors were synthesized by the solid-reaction method. X-ray diffraction （XRD）, diffuse reflection （UV-vis） and photoluminescence spectra ...A series of new red-emitting BaCa1–2xBO3F：xEu3＋, xM＋ （M=Li, Na, K） phosphors were synthesized by the solid-reaction method. X-ray diffraction （XRD）, diffuse reflection （UV-vis） and photoluminescence spectra were utilized to characterize the crystallization process, structure and luminescence properties of the as-synthesized phosphors. The XRD results indicated that the sample began to crystallize at 800 oC, and single-phase BaCaBO3F was fully obtained after annealing at 1000 oC. The charge compensated behaviors were investigated in this paper by considering different cations like Li＋, Na＋ and K＋ acting as the charge compensator. The as-prepared phosphors had better emission properties, and the two characteristic emission lines peaking at 590 and 615 nm could be obtained upon 394, 463 and 532 nm excitation with the chromaticity coordinates of （0.596, 0.391）, which were due to 5D0–7F1 and 5D0–7F2 transitions of Eu3＋ ions. Further, the concentration quenching and corresponding luminescence mechanisms of BaCa1–2xBO3F：xEu3＋, xNa＋ phosphors were also discussed.展开更多
An economic and effective method of preparing enriched 10B boric acid was established by chemical reactionof enriched 10BF3 and CaCO3. A process of boron trifluoride reacting with water was investigated under certainc...An economic and effective method of preparing enriched 10B boric acid was established by chemical reactionof enriched 10BF3 and CaCO3. A process of boron trifluoride reacting with water was investigated under certainconditions. Calcium carbonate was selected to counteract hydrofluoric acid followed on. Some key operation factorswere investigated, such as temperature, reaction time and the ratio of CaCO3 to 10BF3. The results showed that the yieldof enriched 10B boric acid could reach 97. 2% and the purity was up to 94. 1% under the following conditions： the temperaturewas 50-60,℃, the reaction time was 28 h and the ratio of CaCO3 to 10BF3 was 4. In addition, after recrystallizationand titration analysis, the purity of the product could reach over 99. 2% from 94.1%.展开更多
A new complex (1) was prepared by mixing pyridinium polystyrylsulfonate resin and aqueous fluoboric acid, followed by being dehydrated. 1 can be used as an acidic catalyst for the acetalization of benzaldehyde with n-...A new complex (1) was prepared by mixing pyridinium polystyrylsulfonate resin and aqueous fluoboric acid, followed by being dehydrated. 1 can be used as an acidic catalyst for the acetalization of benzaldehyde with n-butanol with a highly catalytic activity. The characterization and reusability of 1 are discussed.展开更多
基金supported by National Natural Science Foundations of China (20876002, 20976002)Natural Science Foundation of Beijing (2082009, 2091002)Funding Project for Academic Human Resources Development in the Institution of Higher Learning under the Jurisdiction of Beijing Municipality
文摘A series of new red-emitting BaCa1–2xBO3F：xEu3＋, xM＋ （M=Li, Na, K） phosphors were synthesized by the solid-reaction method. X-ray diffraction （XRD）, diffuse reflection （UV-vis） and photoluminescence spectra were utilized to characterize the crystallization process, structure and luminescence properties of the as-synthesized phosphors. The XRD results indicated that the sample began to crystallize at 800 oC, and single-phase BaCaBO3F was fully obtained after annealing at 1000 oC. The charge compensated behaviors were investigated in this paper by considering different cations like Li＋, Na＋ and K＋ acting as the charge compensator. The as-prepared phosphors had better emission properties, and the two characteristic emission lines peaking at 590 and 615 nm could be obtained upon 394, 463 and 532 nm excitation with the chromaticity coordinates of （0.596, 0.391）, which were due to 5D0–7F1 and 5D0–7F2 transitions of Eu3＋ ions. Further, the concentration quenching and corresponding luminescence mechanisms of BaCa1–2xBO3F：xEu3＋, xNa＋ phosphors were also discussed.
基金Supported by the Independent Innovation Fund of Tianjin University(No.1307)
文摘An economic and effective method of preparing enriched 10B boric acid was established by chemical reactionof enriched 10BF3 and CaCO3. A process of boron trifluoride reacting with water was investigated under certainconditions. Calcium carbonate was selected to counteract hydrofluoric acid followed on. Some key operation factorswere investigated, such as temperature, reaction time and the ratio of CaCO3 to 10BF3. The results showed that the yieldof enriched 10B boric acid could reach 97. 2% and the purity was up to 94. 1% under the following conditions： the temperaturewas 50-60,℃, the reaction time was 28 h and the ratio of CaCO3 to 10BF3 was 4. In addition, after recrystallizationand titration analysis, the purity of the product could reach over 99. 2% from 94.1%.
基金Supported by the National Natural Science Foundation of China Natural Science Founclation of Tianjin
文摘A new complex (1) was prepared by mixing pyridinium polystyrylsulfonate resin and aqueous fluoboric acid, followed by being dehydrated. 1 can be used as an acidic catalyst for the acetalization of benzaldehyde with n-butanol with a highly catalytic activity. The characterization and reusability of 1 are discussed.
