The long afterglow fluorescent material of M1-3xAl2O4:Eu2+ x/Dy3+2x(M2+= Sr2+, Ca2+ and Ba2+) phosphors are successfully synthesized by calcining precursor obtained via co-precipitation method at 1300oC for 4 h with r...The long afterglow fluorescent material of M1-3xAl2O4:Eu2+ x/Dy3+2x(M2+= Sr2+, Ca2+ and Ba2+) phosphors are successfully synthesized by calcining precursor obtained via co-precipitation method at 1300oC for 4 h with reducing atmosphere (20% H2 and 80% N2). The phase evolution, morphology and afterglow fluorescent properties are systematically studied by the various instruments of XRD, FE-SEM, PLE/PL spectroscopy and fluorescence decay analysis. The PL spectra shows that the Sr1-3xAl2O4:Eu2+x/Dy3+ 2x phosphors display vivid green emission at s519 nm (4f65d1!4f7 transition of Eu2+) with monitoring of the maximum excitation wavelength at s334 nm (8S7=2!6IJ transition of Eu2+), among which the optimal concentration of Eu2+ and Dy3+ is 15 at.% and 30 at.%, respectively. The color coordinates and temperature of Sr1-3xAl2O4:Eu2+ x/Dy3+ 2x phosphors are approximately at (s0.27, s0.57) and s6700 K, respectively. On the above basis, the M0:55Al2O4:Eu2+ 0:15/Dy3+ 0:3 (M2+= Ca2+ and Ba2+) phosphors is obtained by the same method. The PL spectra of these phosphors shows the strongest blue emission at s440 nm and cyan emission at s499 nm under s334 nm wavelength excitation, respectively, which are blue shifted comparing to Sr1??3xAl2O4:Eu2+ x/Dy3+ 2x phosphors. The color coordinates and temperatures of M0:55Al2O4:Eu2+ 0:15/Dy3+ 0:3 (M2+= Ca2+ and Ba2+) phosphors are approximately at (s0.18, s0.09), s2000 K and (s0.18, s0.42), s11600 K, respectively. In this work, long afterglow materials of green, blue and cyan aluminates phosphors with excellent properties have been prepared, in order to obtain wide application in the field of night automatic lighting and display.展开更多
A practical system of metals-(2,4-pentanedionate) (M(acac)n (M= Fe, Zn, Co and V)) and P2O5 in the pres- ence of HNO3 catalyzes regioselective nitration of ar-himachalene 1 to mono-nitro-ar-himachalene 2 in mod- erate...A practical system of metals-(2,4-pentanedionate) (M(acac)n (M= Fe, Zn, Co and V)) and P2O5 in the pres- ence of HNO3 catalyzes regioselective nitration of ar-himachalene 1 to mono-nitro-ar-himachalene 2 in mod- erate to high yields. Under mild conditions, the selectivity of nitration of 1 to 2 is excellent compared to the classical method using the nitro-sulphuric mixture HNO3/H2SO4, both mono- and di-nitro-ar-himachalene 2 and 3 are obtained. The reaction offers a very good method for the preparation of nitro-aromatic compounds and provides a useful entry to new functionalized terpenic products.展开更多
The growth of crystals of the high T c oxide superconductors has been hampe red by the complexities of the materials and their phase diagrams.The most common crys tal growth technique adopted for these oxides is the ...The growth of crystals of the high T c oxide superconductors has been hampe red by the complexities of the materials and their phase diagrams.The most common crys tal growth technique adopted for these oxides is the “flux”method,where the st arting materials are solved in a melt,which is usually formed by excess CuO and BaO or a KCl/NaCl mixture.The crystals are produced by slow cooling of the heate d solvent.This method,however,suffers from several disadvantages: (1) the crystals are contaminated with the crucible material, (2) the crystals are difficult to remove from the crucible, (3) the crystals contain flux inclusions.展开更多
以D-氨基葡萄糖盐酸盐、间硝基苯甲酸和对甲基苯甲酸为原料,先将氨基葡萄糖的羟基加以保护,然后以N,N-二环已基碳二亚胺(DCC)为脱水剂,合成N-硝基苯甲酰基-1,3,4,6-四-O-乙酰基-2-脱氧-β-D-氨基葡萄糖.产品结构经傅里叶变换红外光谱(FT...以D-氨基葡萄糖盐酸盐、间硝基苯甲酸和对甲基苯甲酸为原料,先将氨基葡萄糖的羟基加以保护,然后以N,N-二环已基碳二亚胺(DCC)为脱水剂,合成N-硝基苯甲酰基-1,3,4,6-四-O-乙酰基-2-脱氧-β-D-氨基葡萄糖.产品结构经傅里叶变换红外光谱(FT-IR)及核磁共振氢谱(1 H NMR)表征确认.研究表明:1,3,4,6-四-O-乙酰基-2-脱氧-β-D-氨基葡萄糖、DCC和间硝基苯甲酸/对甲基苯甲酸的摩尔比为1∶1.5∶1.5,反应温度为40℃,反应时间为4h为最佳反应条件.展开更多
以氨基-1,2,4-三唑和2-偕二硝甲基-5-硝基四唑(HDNMNT)为原料,通过中和反应合成出两种新型含能离子盐——2-偕二硝甲基-5-硝基四唑3-氨基-1,2,4-三唑盐(3-ATDNMNT)和2-偕二硝甲基-5-硝基四唑4-氨基-1,2,4-三唑盐(4-ATDNMNT),收率分别为9...以氨基-1,2,4-三唑和2-偕二硝甲基-5-硝基四唑(HDNMNT)为原料,通过中和反应合成出两种新型含能离子盐——2-偕二硝甲基-5-硝基四唑3-氨基-1,2,4-三唑盐(3-ATDNMNT)和2-偕二硝甲基-5-硝基四唑4-氨基-1,2,4-三唑盐(4-ATDNMNT),收率分别为95.4%和96.7%;利用FT-IR、1 H NMR、13C NMR、15 N NMR及元素分析等方法对其结构进行表征;采用量子化学方法计算了3-ATDNMNT和4-ATDNMNT的爆轰性能;在标准状态下(膨胀比为70∶1),利用最小自由能原理,分别计算了两种离子盐在丁羟复合推进剂中的能量性能。结果表明,3-ATDNMNT的爆速和爆压分别为8.587km/s和33.58GPa,4-ATDNMNT的爆速和爆压分别为8.693km/s和34.31GPa。以3-ATDNMNT部分取代丁羟复合推进剂中的AP后,丁羟复合推进剂的理论比冲可达2 635.7N·s/kg。以4-ATDNMNT部分取代丁羟复合推进剂中的AP后,当HTPB、Al、AP及4-ATDNMNT各组分质量分数分别为10%、5%、15%及70%时,获得该丁羟复合推进剂的最高理论比冲为2 677.2N·s/kg。展开更多
基金the National Natural Science Foundation of China (No. 51602126)the National Key Research and Development Plan of China (No. 2016YFB0303505)+1 种基金China and University of Jinan Postdoctoral Science Foundation (No. 2017M622118 and XBH1716)the 111 Project of International Corporation on Advanced Cement-based Materials (D17001).
文摘The long afterglow fluorescent material of M1-3xAl2O4:Eu2+ x/Dy3+2x(M2+= Sr2+, Ca2+ and Ba2+) phosphors are successfully synthesized by calcining precursor obtained via co-precipitation method at 1300oC for 4 h with reducing atmosphere (20% H2 and 80% N2). The phase evolution, morphology and afterglow fluorescent properties are systematically studied by the various instruments of XRD, FE-SEM, PLE/PL spectroscopy and fluorescence decay analysis. The PL spectra shows that the Sr1-3xAl2O4:Eu2+x/Dy3+ 2x phosphors display vivid green emission at s519 nm (4f65d1!4f7 transition of Eu2+) with monitoring of the maximum excitation wavelength at s334 nm (8S7=2!6IJ transition of Eu2+), among which the optimal concentration of Eu2+ and Dy3+ is 15 at.% and 30 at.%, respectively. The color coordinates and temperature of Sr1-3xAl2O4:Eu2+ x/Dy3+ 2x phosphors are approximately at (s0.27, s0.57) and s6700 K, respectively. On the above basis, the M0:55Al2O4:Eu2+ 0:15/Dy3+ 0:3 (M2+= Ca2+ and Ba2+) phosphors is obtained by the same method. The PL spectra of these phosphors shows the strongest blue emission at s440 nm and cyan emission at s499 nm under s334 nm wavelength excitation, respectively, which are blue shifted comparing to Sr1??3xAl2O4:Eu2+ x/Dy3+ 2x phosphors. The color coordinates and temperatures of M0:55Al2O4:Eu2+ 0:15/Dy3+ 0:3 (M2+= Ca2+ and Ba2+) phosphors are approximately at (s0.18, s0.09), s2000 K and (s0.18, s0.42), s11600 K, respectively. In this work, long afterglow materials of green, blue and cyan aluminates phosphors with excellent properties have been prepared, in order to obtain wide application in the field of night automatic lighting and display.
文摘A practical system of metals-(2,4-pentanedionate) (M(acac)n (M= Fe, Zn, Co and V)) and P2O5 in the pres- ence of HNO3 catalyzes regioselective nitration of ar-himachalene 1 to mono-nitro-ar-himachalene 2 in mod- erate to high yields. Under mild conditions, the selectivity of nitration of 1 to 2 is excellent compared to the classical method using the nitro-sulphuric mixture HNO3/H2SO4, both mono- and di-nitro-ar-himachalene 2 and 3 are obtained. The reaction offers a very good method for the preparation of nitro-aromatic compounds and provides a useful entry to new functionalized terpenic products.
文摘The growth of crystals of the high T c oxide superconductors has been hampe red by the complexities of the materials and their phase diagrams.The most common crys tal growth technique adopted for these oxides is the “flux”method,where the st arting materials are solved in a melt,which is usually formed by excess CuO and BaO or a KCl/NaCl mixture.The crystals are produced by slow cooling of the heate d solvent.This method,however,suffers from several disadvantages: (1) the crystals are contaminated with the crucible material, (2) the crystals are difficult to remove from the crucible, (3) the crystals contain flux inclusions.
文摘以D-氨基葡萄糖盐酸盐、间硝基苯甲酸和对甲基苯甲酸为原料,先将氨基葡萄糖的羟基加以保护,然后以N,N-二环已基碳二亚胺(DCC)为脱水剂,合成N-硝基苯甲酰基-1,3,4,6-四-O-乙酰基-2-脱氧-β-D-氨基葡萄糖.产品结构经傅里叶变换红外光谱(FT-IR)及核磁共振氢谱(1 H NMR)表征确认.研究表明:1,3,4,6-四-O-乙酰基-2-脱氧-β-D-氨基葡萄糖、DCC和间硝基苯甲酸/对甲基苯甲酸的摩尔比为1∶1.5∶1.5,反应温度为40℃,反应时间为4h为最佳反应条件.
文摘以氨基-1,2,4-三唑和2-偕二硝甲基-5-硝基四唑(HDNMNT)为原料,通过中和反应合成出两种新型含能离子盐——2-偕二硝甲基-5-硝基四唑3-氨基-1,2,4-三唑盐(3-ATDNMNT)和2-偕二硝甲基-5-硝基四唑4-氨基-1,2,4-三唑盐(4-ATDNMNT),收率分别为95.4%和96.7%;利用FT-IR、1 H NMR、13C NMR、15 N NMR及元素分析等方法对其结构进行表征;采用量子化学方法计算了3-ATDNMNT和4-ATDNMNT的爆轰性能;在标准状态下(膨胀比为70∶1),利用最小自由能原理,分别计算了两种离子盐在丁羟复合推进剂中的能量性能。结果表明,3-ATDNMNT的爆速和爆压分别为8.587km/s和33.58GPa,4-ATDNMNT的爆速和爆压分别为8.693km/s和34.31GPa。以3-ATDNMNT部分取代丁羟复合推进剂中的AP后,丁羟复合推进剂的理论比冲可达2 635.7N·s/kg。以4-ATDNMNT部分取代丁羟复合推进剂中的AP后,当HTPB、Al、AP及4-ATDNMNT各组分质量分数分别为10%、5%、15%及70%时,获得该丁羟复合推进剂的最高理论比冲为2 677.2N·s/kg。
