The present paper reported the structural and luminescent properties of Eu^（2＋） and Nd^（3＋） doped CaAl_2O_4 phosphor. The samples were prepared by microwave-assisted chemical co-precipitation（MA-CCP）, a synthe...The present paper reported the structural and luminescent properties of Eu^（2＋） and Nd^（3＋） doped CaAl_2O_4 phosphor. The samples were prepared by microwave-assisted chemical co-precipitation（MA-CCP）, a synthesis technique which is suitable for small and uniform particle that could be used directly without grinding. The effects of different microwave temperatures on structure and photoluminescence behavior were studied. Formation of a phosphor and phase purity were confirmed by X-ray diffraction technique（XRD） with variable microwave temperatures. XRD analysis showed that the phosphors prepared by MA-CCP method at the temperature of 750, 900oC, respectively and solid-state reaction（SSR） method at 1300oC consisted of impurities. Commission Internationale de L＇Eclairage（CIE） color coordinates of CaAl_2O_4：Eu^（2＋）,Nd^（3＋） were suitable as blue light emitting phosphor. Excitation and emission peaks of the samples prepared by different methods in this study were almost the same. The images of SEM showed that the size of the phosphors prepared by MA-CCP method reached a submicrometer.展开更多
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
为探究不同稻-鸭-虾种养模式与水稻单作模式和传统稻-虾种养模式的碳排放及碳固定特征差异,于湖北省荆州市华中农业大学双水双绿研究基地开展大田试验,以水稻品种华墨香5号、克氏原螯虾(Procambarus clarki)、肉鸭武禽10号为试验材料,...为探究不同稻-鸭-虾种养模式与水稻单作模式和传统稻-虾种养模式的碳排放及碳固定特征差异,于湖北省荆州市华中农业大学双水双绿研究基地开展大田试验,以水稻品种华墨香5号、克氏原螯虾(Procambarus clarki)、肉鸭武禽10号为试验材料,研究水稻单作(monoculture,CK1)模式、稻-虾种植(rice-crayfish coculture,CK2)、稻-鸭-虾单元格投放(rice-duck-crayfish unit release model,CRXD)、稻-鸭-虾“游牧鸭”(rice-duckcrayfish“nomadic duck”model,NRXD)、稻-鸭-虾大田块(rice-duck-crayfish large field block model,BRXD)共5种养模式下稻田甲烷(methane,CH4)、氧化亚氮(nitrous oxide,N2O)排放、全球增温潜势(global warming potential,GWP)、温室气体排放强度(greenhouse gas emission intensity,GHGI)以及碳固定潜力。结果显示,相比传统水稻单作模式,稻-鸭-虾模式降低了稻田CH4排放、GWP、GHGI,碳中和效应显著增加。与水稻单作相比,稻-鸭-虾模式CH4的排放量降低了28.1%~32.1%,GWP降低了27.0%~30.7%,GHGI降低了23.0%~26.7%,碳固定增加了2089~2569 kg/hm^(2)。与稻-虾种养相比,稻-鸭-虾模式的CH4排放量降低了18.6%~23.1%,GWP降低了17.9%~22.2%,GHGI下降18.7%~22.0%,碳固定增加了616~1096 kg/hm^(2)。结果表明,稻-鸭-虾模式可以降低稻田碳排放量,提高稻田碳中和潜力,其中稻-鸭-虾大田块模式固碳减排效果最佳。展开更多
基金Project supported by the Fundamental Research Funds for the Central Universities(JUSRP51723B)National Natural Science Foundation of China(51503083)+2 种基金Jiangsu Province Ordinary University Academic Degree Graduate Student Scientific Research Innovation Projects(KYLX16_0798)the Priority Academic Program Development of Jiangsu Higher Education InstitutionsProduction,Education&Research Cooperative Innovation Fund Project of Jiangsu Province(BY2015057-23)
文摘The present paper reported the structural and luminescent properties of Eu^（2＋） and Nd^（3＋） doped CaAl_2O_4 phosphor. The samples were prepared by microwave-assisted chemical co-precipitation（MA-CCP）, a synthesis technique which is suitable for small and uniform particle that could be used directly without grinding. The effects of different microwave temperatures on structure and photoluminescence behavior were studied. Formation of a phosphor and phase purity were confirmed by X-ray diffraction technique（XRD） with variable microwave temperatures. XRD analysis showed that the phosphors prepared by MA-CCP method at the temperature of 750, 900oC, respectively and solid-state reaction（SSR） method at 1300oC consisted of impurities. Commission Internationale de L＇Eclairage（CIE） color coordinates of CaAl_2O_4：Eu^（2＋）,Nd^（3＋） were suitable as blue light emitting phosphor. Excitation and emission peaks of the samples prepared by different methods in this study were almost the same. The images of SEM showed that the size of the phosphors prepared by MA-CCP method reached a submicrometer.
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.
文摘为探究不同稻-鸭-虾种养模式与水稻单作模式和传统稻-虾种养模式的碳排放及碳固定特征差异,于湖北省荆州市华中农业大学双水双绿研究基地开展大田试验,以水稻品种华墨香5号、克氏原螯虾(Procambarus clarki)、肉鸭武禽10号为试验材料,研究水稻单作(monoculture,CK1)模式、稻-虾种植(rice-crayfish coculture,CK2)、稻-鸭-虾单元格投放(rice-duck-crayfish unit release model,CRXD)、稻-鸭-虾“游牧鸭”(rice-duckcrayfish“nomadic duck”model,NRXD)、稻-鸭-虾大田块(rice-duck-crayfish large field block model,BRXD)共5种养模式下稻田甲烷(methane,CH4)、氧化亚氮(nitrous oxide,N2O)排放、全球增温潜势(global warming potential,GWP)、温室气体排放强度(greenhouse gas emission intensity,GHGI)以及碳固定潜力。结果显示,相比传统水稻单作模式,稻-鸭-虾模式降低了稻田CH4排放、GWP、GHGI,碳中和效应显著增加。与水稻单作相比,稻-鸭-虾模式CH4的排放量降低了28.1%~32.1%,GWP降低了27.0%~30.7%,GHGI降低了23.0%~26.7%,碳固定增加了2089~2569 kg/hm^(2)。与稻-虾种养相比,稻-鸭-虾模式的CH4排放量降低了18.6%~23.1%,GWP降低了17.9%~22.2%,GHGI下降18.7%~22.0%,碳固定增加了616~1096 kg/hm^(2)。结果表明,稻-鸭-虾模式可以降低稻田碳排放量,提高稻田碳中和潜力,其中稻-鸭-虾大田块模式固碳减排效果最佳。
