A series of novel red phosphors LiEu1-xYx(WO4)0.5(MoO4)1.5 (x=0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8) were synthesized by conventional solid state reaction method with the starting materials: WO3, MoO3, Eu2O3, Li2CO3 an...A series of novel red phosphors LiEu1-xYx(WO4)0.5(MoO4)1.5 (x=0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8) were synthesized by conventional solid state reaction method with the starting materials: WO3, MoO3, Eu2O3, Li2CO3 and Y2O3. The spectrum and the crystal structure of the phosphors were characterized by F-4500 and XRD respectively. Meanwhile the effects of flux and Y3+ concentration on the crystal structure and luminescent properties of the phosphors were investigated. The results showed that the optimal content of flux (WAlF3/WH3BO3=1/1) was 1 wt% and the optimal doping concentration of Y3+ was 0.5 mol. The emission spectrum showed the most intense peak was located at 615 nm, which corresponds to the 5D0→7F2 transition of Eu3+ and that Eu3+ occupied the lattice site of noncentrosymmetric environment in the scheelite phases. The excitation spectrum displayed that these phosphors could be effectively excited by ultraviolet (UV) (396 nm) and blue (466 nm) light, nicely in correspondence with the widely ap- plied output wavelengths of ultraviolet or blue LED chips. The influence of flux on the luminescent properties of LiEu0.5Y0.5(WO4)0.5(MoO4)1.5 phosphor was analyzed. The XRD spectra indicated that the flux could help to crystallize the phosphor, and no other phases were formed except the tetragonal. When adding flux, the relative intensity of LiEu0.5Y0.5(WO4)0.5(MoO4)1.5 became much stronger and the average particle size of the phosphor decreased.展开更多
The Bi3＋ doped molybdate-based red-emitting phosphors, LiEu1-xBix（MoO4）2, were successfully synthesized with a sol-gel method. The prepared LiEu1-xBix（MoO4）2 phosphors exhibited pure and intense red emission at 6...The Bi3＋ doped molybdate-based red-emitting phosphors, LiEu1-xBix（MoO4）2, were successfully synthesized with a sol-gel method. The prepared LiEu1-xBix（MoO4）2 phosphors exhibited pure and intense red emission at 613 nm under the excitation of near-UV 394 nm. It was discussed in detail that the influence of the synthesis conditions such as the doping concentration of Bi3, the dose of citric acid, pH of the precursor solution and the sintering temperature on the emission intensity of the phosphors. According to the results, the optimal condition was obtained： the doping concentration of Bi3＋ was 15 mol.%, molar ratio of citric acid to metal ions was 1.5：1, pH of the precursor solution was 1.0 and the sintering temperature was 800 ℃. The X-ray diffraction （XRD） patterns of the LiEuo.85Bi0.15（MoO4）2 phosphor prepared under the optimal condition indicated that the phosphor was single phase with tetragonal scheelite structure. The Commission Intemationale de I＇E- clairage （CIE） chromaticity coordinates of LiEuo.85Bio.15（MoO4）2 were （x=0.655, y=0.345）, which were closer to the national television stan- dard committee （NTSC） standard values （x=0.670, y=0.330） than that of a commercial red phosphor of Y202S：Eu3＋（x=0.630, y=0.350）. This LiEuo.85Bi0As（MoO4）2 red phosphor is a promising candidate for the fabrication of white light-emitting diode （W-LED） with near-UV chips.展开更多
目的系统评价厚朴排合剂治疗早期术后肠麻痹的有效性和安全性。方法检索数据库中国知网、万方数据、维普网、中国生物医学文献数据库、Cochrane、PubMed、Embase、Web of Science,检索时间为自建库至2021年4月30日,汇总厚朴排气合剂医...目的系统评价厚朴排合剂治疗早期术后肠麻痹的有效性和安全性。方法检索数据库中国知网、万方数据、维普网、中国生物医学文献数据库、Cochrane、PubMed、Embase、Web of Science,检索时间为自建库至2021年4月30日,汇总厚朴排气合剂医治术后早期肠麻痹的RCT试验,最后结合Cochrane5.1版评价手册的标准以RevMan5.3版评价软件对纳入文献进行Meta分析。结果共纳入Meta分析的13个研究共涉及患者1836例,其中试验组患者1199例,对照组患者637例。Meta分析显示,在缩短首次肛门排气时间方面,厚朴排气合剂联合常规治疗优于单用常规治疗[MD=-8.41,95%CI(-10.37,-6.45),P<0.00001];在缩短肠鸣音恢复时间方面,厚朴排气合剂联合常规治疗优于单用常规治疗[MD=-5.13,95%CI(-6.39,-3.87),P<0.00001];在缩短首次排便时间方面,厚朴排气合剂联合常规治疗优于单用常规治疗[MD=-11.79,95%CI(-15.14,-8.44),P<0.00001],厚朴排气合剂优于空白对照[MD=-5.27,95%CI(-7.10,-3.45),P<0.00001];在缩短术后住院时间方面,厚朴排气合剂联合常规治疗优于单用常规治疗[MD=-2.35,95%CI(-3.08,-1.62),P<0.00001]。不良反应主要表现为恶心、呕吐、腹泻等症状,多数表现为恶心、呕吐的不良反应症状较轻,未作处置,症状消失。结论基于当前可使用的数据和方法,厚朴排气合剂联合常规治疗或单用来治疗术后早期肠麻痹时,能缩短首次肛门排气时间、肠鸣音恢复时间、首次排便时间及术后住院时间,且多数不良反应症状相对较轻,并可自行消失。由于当前所纳入研究质量不高,尚不能提供高质量证据证实其临床疗效,需要更多设计良好、规模较大的多中心随机对照试验进一步加以验证。展开更多
基金Supported by the Key Programs for Science and Technology Development of Hubei Province(Grant No.2005AA105A05)
文摘A series of novel red phosphors LiEu1-xYx(WO4)0.5(MoO4)1.5 (x=0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8) were synthesized by conventional solid state reaction method with the starting materials: WO3, MoO3, Eu2O3, Li2CO3 and Y2O3. The spectrum and the crystal structure of the phosphors were characterized by F-4500 and XRD respectively. Meanwhile the effects of flux and Y3+ concentration on the crystal structure and luminescent properties of the phosphors were investigated. The results showed that the optimal content of flux (WAlF3/WH3BO3=1/1) was 1 wt% and the optimal doping concentration of Y3+ was 0.5 mol. The emission spectrum showed the most intense peak was located at 615 nm, which corresponds to the 5D0→7F2 transition of Eu3+ and that Eu3+ occupied the lattice site of noncentrosymmetric environment in the scheelite phases. The excitation spectrum displayed that these phosphors could be effectively excited by ultraviolet (UV) (396 nm) and blue (466 nm) light, nicely in correspondence with the widely ap- plied output wavelengths of ultraviolet or blue LED chips. The influence of flux on the luminescent properties of LiEu0.5Y0.5(WO4)0.5(MoO4)1.5 phosphor was analyzed. The XRD spectra indicated that the flux could help to crystallize the phosphor, and no other phases were formed except the tetragonal. When adding flux, the relative intensity of LiEu0.5Y0.5(WO4)0.5(MoO4)1.5 became much stronger and the average particle size of the phosphor decreased.
基金Project supported by National Natural Science Foundation of China (NSFC20803097, NSFC20603049)Natural Science Foundation of Chongqing (CSTC2011AB4056, CSTC2009BA4023)the Fundamental Research Funds for the Central Universities (CDJZR10220005 and CDJRC10220002)
文摘The Bi3＋ doped molybdate-based red-emitting phosphors, LiEu1-xBix（MoO4）2, were successfully synthesized with a sol-gel method. The prepared LiEu1-xBix（MoO4）2 phosphors exhibited pure and intense red emission at 613 nm under the excitation of near-UV 394 nm. It was discussed in detail that the influence of the synthesis conditions such as the doping concentration of Bi3, the dose of citric acid, pH of the precursor solution and the sintering temperature on the emission intensity of the phosphors. According to the results, the optimal condition was obtained： the doping concentration of Bi3＋ was 15 mol.%, molar ratio of citric acid to metal ions was 1.5：1, pH of the precursor solution was 1.0 and the sintering temperature was 800 ℃. The X-ray diffraction （XRD） patterns of the LiEuo.85Bi0.15（MoO4）2 phosphor prepared under the optimal condition indicated that the phosphor was single phase with tetragonal scheelite structure. The Commission Intemationale de I＇E- clairage （CIE） chromaticity coordinates of LiEuo.85Bio.15（MoO4）2 were （x=0.655, y=0.345）, which were closer to the national television stan- dard committee （NTSC） standard values （x=0.670, y=0.330） than that of a commercial red phosphor of Y202S：Eu3＋（x=0.630, y=0.350）. This LiEuo.85Bi0As（MoO4）2 red phosphor is a promising candidate for the fabrication of white light-emitting diode （W-LED） with near-UV chips.
文摘目的系统评价厚朴排合剂治疗早期术后肠麻痹的有效性和安全性。方法检索数据库中国知网、万方数据、维普网、中国生物医学文献数据库、Cochrane、PubMed、Embase、Web of Science,检索时间为自建库至2021年4月30日,汇总厚朴排气合剂医治术后早期肠麻痹的RCT试验,最后结合Cochrane5.1版评价手册的标准以RevMan5.3版评价软件对纳入文献进行Meta分析。结果共纳入Meta分析的13个研究共涉及患者1836例,其中试验组患者1199例,对照组患者637例。Meta分析显示,在缩短首次肛门排气时间方面,厚朴排气合剂联合常规治疗优于单用常规治疗[MD=-8.41,95%CI(-10.37,-6.45),P<0.00001];在缩短肠鸣音恢复时间方面,厚朴排气合剂联合常规治疗优于单用常规治疗[MD=-5.13,95%CI(-6.39,-3.87),P<0.00001];在缩短首次排便时间方面,厚朴排气合剂联合常规治疗优于单用常规治疗[MD=-11.79,95%CI(-15.14,-8.44),P<0.00001],厚朴排气合剂优于空白对照[MD=-5.27,95%CI(-7.10,-3.45),P<0.00001];在缩短术后住院时间方面,厚朴排气合剂联合常规治疗优于单用常规治疗[MD=-2.35,95%CI(-3.08,-1.62),P<0.00001]。不良反应主要表现为恶心、呕吐、腹泻等症状,多数表现为恶心、呕吐的不良反应症状较轻,未作处置,症状消失。结论基于当前可使用的数据和方法,厚朴排气合剂联合常规治疗或单用来治疗术后早期肠麻痹时,能缩短首次肛门排气时间、肠鸣音恢复时间、首次排便时间及术后住院时间,且多数不良反应症状相对较轻,并可自行消失。由于当前所纳入研究质量不高,尚不能提供高质量证据证实其临床疗效,需要更多设计良好、规模较大的多中心随机对照试验进一步加以验证。
