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Spectral and laser properties of Yb and Ho co-doped(YLa)_2O_3 transparent ceramic 被引量:2
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作者 黄栋栋 杨秋红 +4 位作者 王永刚 张浩佳 陆神洲 邹育婉 魏志义 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第3期505-507,共3页
Highly transparent Yb,Ho doped(YLa)2O3 ceramic was fabricated by conventional ceramic processing with nanopowders.The absorption and emission spectra of the ceramic was investigated.The energy transfer mechanism bet... Highly transparent Yb,Ho doped(YLa)2O3 ceramic was fabricated by conventional ceramic processing with nanopowders.The absorption and emission spectra of the ceramic was investigated.The energy transfer mechanism between Yb3+ and Ho3+ was also discussed.The strong emission band around 2 μm indicated that the Yb-Ho:(Y 0.90 La 0.10)2O3 transparent ceramic is a promising gain medium for the generation of 2 μm laser emissions.The laser operation of Yb-Ho co-doped(YLa)2O3 ceramic at 2.1 μm is first reported. 展开更多
关键词 Yb-Ho doped(YLa)2O3 transparent ceramic spectral properties 2 μm laser
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Synthesis of M1-3xAl2O4:Eu2+x/Dy3+ 2x(M^2+= Sr^2+, Ca^2+ and Ba^2+) phosphors with long-lasting phosphorescence properties via co-precipitation method 被引量:1
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作者 Jinkai Li Bin Liu +2 位作者 Qi Chen Yizhong Lu Zongming Liu 《Chemical Reports》 2019年第2期112-117,共6页
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
关键词 long AFTERGLOW material CO-PRECIPITATION method m1-3xAl2O4:Eu2+ x/Dy3+ 2x(m2+= Sr2+ Ca2+ and Ba2+) PHOSPHORS luminescent property
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Synthesis and electrical properties of In_2O_3(ZnO)_m superlattice nanobelt
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作者 唐欣月 高红 +4 位作者 武立立 温静 潘思明 刘欣 张喜田 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第2期394-398,共5页
One-dimensional(ID) In2O3(ZnO)m superlattice nanobelts are synthesized by a chemical vapor deposition method.The formation of the In2O3(ZnO)m superlattice is verified by the high-resolution transmission electron... One-dimensional(ID) In2O3(ZnO)m superlattice nanobelts are synthesized by a chemical vapor deposition method.The formation of the In2O3(ZnO)m superlattice is verified by the high-resolution transmission electron microscopy images.The typical zigzag boundaries could be clearly observed.An additional peak at 614 cm^-1 is found in the Raman spectrum,which may correspond to the superlattice structure.The study about the electrical transport properties reveals that the In2O3(ZnO)m nanobelts exhibit peculiar nonlinear I-V characteristics even under the Ohmic contact measurement condition,which are different from the Ohmic behaviors of the In-doped ZnO nanobelts.The photoelectrical measurements show the differences in the photocurrent property between them,and their transport mechanisms are also discussed. 展开更多
关键词 In2O3(ZnO)m SUPERLATTICE electrical properties
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First principles study on lattice vibration and electrical properties of layered perovskite Sr_2M_2O_7(M=Nb, Ta)
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作者 Xing Liu Hui-Qing Fan 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第8期406-414,共9页
In this paper, we performed calculations to investigate the dielectric, piezoelectric properties, Born effective charge (BEC), and spontaneous polarization of Sr2M207, the method used in our study was a well-known d... In this paper, we performed calculations to investigate the dielectric, piezoelectric properties, Born effective charge (BEC), and spontaneous polarization of Sr2M207, the method used in our study was a well-known density functional theory based on first-principles. The optimized results were in good agreement with previous experiments and calculations. which indicates that our calculated method is reasonable. The research we have done suggested that greater piezoelectric components of Sr2Nb207 were e31 and e33, and the contributions were derived from the A I. By studying the Born effective charge, it could be seen that the valence of ions changed, and the O of Sr2Nb207 were most obviously that caused by the covalent character of ions and the hybridization of O-2p and Nb-4d. The spontaneous polarization of Sr2Nb2O7 in the [001 ] direction is 25 p_C/cm2, while for Sr2Ta2O7, there was no spontaneous polarization in the paraelectric state. Finally, the effect of pressure on the piezoelectric properties were also investigated, the polarization of Sr2Nb2O7 decreased linearly with the increase alter pressure. All our preliminary results throw light on the nature of dielectric, piezoelectric properties, Born effective charge, and spontaneous polarization of Sr2M2OT, it was helpful for experimental research, the development of new materials, and future applications. 展开更多
关键词 Sr2m2O7 first-principles dielectric and piezoelectric properties Born effective charge sponta-neous polarization
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Emission property of Y_2O_3-doped Mo secondary emitter
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作者 王金淑 刘伟 +3 位作者 李洪义 高非 任志远 周美玲 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第2期233-237,共5页
Y2O3-doped Mo secondary emitters were prepared by liquid-liquid doping and solid-solid doping,respectively.The back-scattered scanning observation result indicates that the emitter prepared by liquid-liquid doping has... Y2O3-doped Mo secondary emitters were prepared by liquid-liquid doping and solid-solid doping,respectively.The back-scattered scanning observation result indicates that the emitter prepared by liquid-liquid doping has fine microstructure whereas that prepared by solid-solid doping has large grain size.Y2O3-doped Mo emitter with small grain size prepared by liquid-liquid doping exhibits high emission property,i.e.,the secondary electron yield can get to 5.24,about 1.7 times that prepared by solid-solid doping.Moreover,Y2O3-doped Mo emitter exhibits the best emission performance among La2O3-doped Mo,Y2O3-doped Mo, Gd2O3-doped Mo and Ce2O3-doped Mo emitters due to the largest penetration depth of primary electrons and escape depth of secondary electrons in this emitter.The secondary emission of the emitter with small grain size can be explained by reflection emission model and transmission emission model,whereas only transmission emission exists in the emitter with large grain size. 展开更多
关键词 Y2O3-doped mo powder metallurgy emission property microstructure
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ZnAl_(2)O_(4):Mn材料的制备及发光性能
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作者 吕莉 刘琳 +2 位作者 韩梅杏 杨慧君 刘会影 《无机化学学报》 SCIE CAS CSCD 北大核心 2023年第6期1113-1121,共9页
以共沉淀法与煅烧法联用,成功制备了一系列ZnAl_(2)O_(4):xMn样品。通过扫描电镜和X射线粉末衍射测试研究了样品的形貌和物相特征,结果表明尖晶石结构的ZnAl_(2)O_(4)中[AlO_(6)]的八面体位可以有效被Mn^(4+)替代。通过荧光激发和发射... 以共沉淀法与煅烧法联用,成功制备了一系列ZnAl_(2)O_(4):xMn样品。通过扫描电镜和X射线粉末衍射测试研究了样品的形貌和物相特征,结果表明尖晶石结构的ZnAl_(2)O_(4)中[AlO_(6)]的八面体位可以有效被Mn^(4+)替代。通过荧光激发和发射光谱研究了样品的发光性能,发现Mn^(4+)在ZnAl_(2)O_(4)体系中掺杂可以显示出明亮的红色发光(发射峰值位于680 nm处)。比较不同Mn^(4+)浓度(Mn与Al的物质的量之比)掺杂样品的发光强度时发现,Mn4+最佳掺杂浓度为0.06%。通过德克斯特公式分析了发光强度与浓度关系,探究浓度猝灭机制,结果表明最邻近离子之间能量传递造成Mn4+浓度猝灭的发生。为了提高Mn4+的发光强度,选择了7种金属离子(Li^(+)、Na^(+)、K^(+)、Ca^(2+)、Sr^(2+)、Sn^(2+)和Ga^(3+))与Mn^(4+)共掺杂进入ZnAl_(2)O_(4)基质中,其中效果较突出的为Li^(+)和Ga^(3+),其共掺杂使Mn^(4+)发光强度分别增强0.6倍和1倍。 展开更多
关键词 共沉淀-煅烧 ZnAl_(2)O_(4):mn 红光发射 共掺杂 发光性能
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超临界CO_(2)作用下高阶煤微观结构及力学特性-声发射特征研究
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作者 刘佳佳 许艳之 +3 位作者 聂子硕 张云龙 高建良 王丹 《煤炭科学技术》 EI CAS CSCD 北大核心 2024年第10期127-135,共9页
超临界CO_(2)压裂技术作为极具发展潜力的压裂煤体增透瓦斯技术,明晰其对煤体的影响机制,有助于推动该技术的机理研究和实践工程应用。为准确表征超临界CO_(2)作用下高阶煤的孔裂隙结构及力学特性变化,以焦煤集团中马村矿的高阶煤为试... 超临界CO_(2)压裂技术作为极具发展潜力的压裂煤体增透瓦斯技术,明晰其对煤体的影响机制,有助于推动该技术的机理研究和实践工程应用。为准确表征超临界CO_(2)作用下高阶煤的孔裂隙结构及力学特性变化,以焦煤集团中马村矿的高阶煤为试验对象,通过自主搭建的超临界CO_(2)浸泡试验系统,结合全自动物理吸附仪(BET)以及全自动压汞仪(MIP),对超临界CO_(2)处理前后高阶煤的孔裂隙结构变化进行分析,并利用单轴压缩和声发射试验系统对超临界CO_(2)处理前后高阶煤的单轴压缩力学特性和声发射特征进行测定。结果表明:超临界CO_(2)对高阶煤具有良好的扩孔增渗作用。超临界CO_(2)处理后高阶煤的微小孔孔容占比降低,中大孔孔容占比增大,且高阶煤的总孔容增大;超临界CO_(2)对高阶煤的力学特性具有明显的劣化作用。超临界CO_(2)处理后高阶煤单轴抗压强度和弹性模量均显著下降,降幅分别为70.06%和55.56%,且超临界CO_(2)处理后高阶煤的内部声发射信号活跃度明显下降,高阶煤单轴抗压时间、累计振铃计数以及累计能量分别降低了98.68 s、95.14×10^(3)个、200.30 V·ms,降幅分别为46.65%、37.65%、50.03%,高阶煤累计振铃计数以及累计能量平静期占比均显著增加,缓增期占比均降低,激增期前者占比降低,后者占比小幅度增加。研究成果将有助于推动超临界CO_(2)压裂技术的机理研究,对深部高阶煤的煤层气开采和CO_(2)地下封存具有一定指导意义。 展开更多
关键词 超临界CO_(2) 高阶煤 孔隙结构 力学特性 声发射特性 扩孔增渗
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4p阶内2-闭群的m-DCI-性 被引量:7
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作者 徐尚进 张翠 +1 位作者 赵旭波 吴正飞 《广西师范大学学报(自然科学版)》 CAS 北大核心 2006年第1期45-48,共4页
C ay ley图的C I性是研究其同构问题的重要性质。考察一类内2-闭群G=〈a,b a2α=bp=1,-a 1ba=-b 1〉当α=2时的(弱)m-(D)C I-性,并证明G是3-DC I-群和弱5-C I-群。
关键词 2闭群 CAYLEY图 图同构 m—DCI-性
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SrIn_2O_4∶Sm^(3+)红色荧光粉的发光特性 被引量:11
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作者 刘海燕 孙明生 +1 位作者 杨志平 杨艳民 《发光学报》 EI CAS CSCD 北大核心 2011年第1期38-41,共4页
采用燃烧法合成了SrIn2O4:Sm3+红色荧光粉并研究了其发光性质。发射光谱由位于红橙区的3个主要荧光发射峰组成,峰值分别为568,606,660nm,对应Sm3+的4G5/2→6H5/2、4G5/2→6H7/2和4G5/2→6H9/2特征跃迁发射,其中606nm的发射最强。激发光... 采用燃烧法合成了SrIn2O4:Sm3+红色荧光粉并研究了其发光性质。发射光谱由位于红橙区的3个主要荧光发射峰组成,峰值分别为568,606,660nm,对应Sm3+的4G5/2→6H5/2、4G5/2→6H7/2和4G5/2→6H9/2特征跃迁发射,其中606nm的发射最强。激发光谱包括峰值位于323,413nm的宽带,说明该荧光粉可以被近紫外-紫色发光二极管管芯激发发射红光。研究了Sm3+的掺杂浓度对样品发光强度的影响。实验结果表明SrIn2O4:Sm3+是一种可用于制作白光LED的红色荧光粉。 展开更多
关键词 LED 荧光粉 Sm3+ SrIn2O4
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LiNi_yM_(1-y)O_2(M=Co,Mn,Ti,0 被引量:2
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作者 高虹 《电源技术》 CAS CSCD 北大核心 2001年第4期264-267,共4页
对LiNiO2 派生物LiNiyM1-yO2 (M =Co ,Mn ,Ti,0 <y <1)的制备和性能进行了研究。在LiNiyM1-yO2 (M =Co ,Mn ,Ti,0 <y <1)中 ,Li0 .99Ni0 .79Co0 .2 0 O2 ,Li0 .99Ni0 .69Mn0 .2 9O2 ,Li0 .99Ni0 .69Ti0 .3 0 O2 的电化学性... 对LiNiO2 派生物LiNiyM1-yO2 (M =Co ,Mn ,Ti,0 <y <1)的制备和性能进行了研究。在LiNiyM1-yO2 (M =Co ,Mn ,Ti,0 <y <1)中 ,Li0 .99Ni0 .79Co0 .2 0 O2 ,Li0 .99Ni0 .69Mn0 .2 9O2 ,Li0 .99Ni0 .69Ti0 .3 0 O2 的电化学性能比较好 ,均能使放电平台提高 ,放电平稳 ,其中Li0 .99Ni0 .79Co0 .2 0 O2 的循环性能得到改善。研究了Li0 .99Ni0 .79Co0 .2 0 O2 ,Li0 .99Ni0 .69Mn0 .2 9O2 ,Li0 .99 Ni0 .69Ti0 .3 0 O2 的结构和充放电反应机理 ,它们的充放电反应机理同LiNiO2 的充放电反应机理 。 展开更多
关键词 LiNim1-yO2 正极材料 电化学性能 充放电反应机理 锂离蓄电池
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M-ZrO2微球的制备及其光吸收特性
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作者 傅小明 倪宗铭 +2 位作者 方颖 杨在志 孙虎 《广州化工》 CAS 2019年第10期30-32,共3页
以碱式碳酸锆(ZrCO3(OH)2·ZrO2)为锆源,ZrCO3(OH)2·ZrO2在空气中热重-热差(TG-DTA)分析为依据,利用X射线衍射仪(XRD)、扫描电镜(SEM)和紫外-可见分光光度计(UV-Vis)分别表征了ZrCO3(OH)2·ZrO2在空气中热分解产物的物相... 以碱式碳酸锆(ZrCO3(OH)2·ZrO2)为锆源,ZrCO3(OH)2·ZrO2在空气中热重-热差(TG-DTA)分析为依据,利用X射线衍射仪(XRD)、扫描电镜(SEM)和紫外-可见分光光度计(UV-Vis)分别表征了ZrCO3(OH)2·ZrO2在空气中热分解产物的物相、形貌和光吸收特性。研究结果表明,ZrCO3(OH)2·ZrO2在空气中的热分解过程主要分为两个阶段,第一阶段是在室温~200℃之间ZrCO3(OH)2·ZrO2受热失去OH-生成ZrCO3.ZrO2,第二阶段是在200~800℃范围内ZrCO3经过受热分解生产了M-ZrO2,其形貌“遗传”了ZrCO3(OH)2·ZrO2的原始形貌。在900℃下保温15min获得了M-ZrO2微球。M-ZrO2微球具有“红移”现象。 展开更多
关键词 碱式碳酸锆 热分解 m-ZrO2微球 光吸收特性
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Li_(2)MSiO_(4)(M=Mn,Fe,Co)力学性能对电化学特性的影响 被引量:1
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作者 郑寿红 李伟 +3 位作者 姜茗浩 闫小童 侯育花 陶小马 《功能材料》 CAS CSCD 北大核心 2021年第6期6084-6089,共6页
由于硅酸盐类正极材料Li_(2)MSiO_(4)(M=Mn,Fe,Co)较高的理论放电比容量使得其受到广泛的关注,然而其在电化学特性及循环稳定性上的不足,限制了其进一步的发展。采用基于密度泛函理论框架下的第一性原理计算方法,结合Hubbard修正的广义... 由于硅酸盐类正极材料Li_(2)MSiO_(4)(M=Mn,Fe,Co)较高的理论放电比容量使得其受到广泛的关注,然而其在电化学特性及循环稳定性上的不足,限制了其进一步的发展。采用基于密度泛函理论框架下的第一性原理计算方法,结合Hubbard修正的广义梯度近似(GGA+U),系统地研究了Li_(2)MSiO_(4)(M=Mn,Fe,Co)体系的力学性能对其电化学特性的影响。计算结果表明Li_(2)MSiO_(4)(M=Mn,Fe,Co)体系均具有良好的韧性,其中Li_(2)FeSiO_(4)的力学性能最佳,与Li_(2)FeSiO_(4)具备优异循环稳定性的实验报道符合较好。此外,研究发现Li_(2)CoSiO_(4)具有最高的杨氏模量E与德拜温度θD,这与其具备较高的放电电压和Li^(+)从Li_(2)CoSiO_(4)中脱离较难的事实是相符合的。 展开更多
关键词 第一性原理计算 力学性能 正极材料 Li_(2)mSiO_(4)(m=mn Fe Co) 脱嵌电压
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Evaluation of H2 Influence on the Evolution Mechanism of NOx Storage and Reduction over Pt–Ba–Ce/c-Al2O3 Catalysts 被引量:3
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作者 Pan Wang Jing Yi +2 位作者 Chuan Sun Peng Luo Lili Lei 《Engineering》 SCIE EI 2019年第3期568-575,共8页
In this investigation, Pt–Ba–Ce/c-Al2O3 catalysts were prepared by incipient wetness impregnation and experiments were performed to evaluate the influence of H2 on the evolution mechanism of nitrogen oxides (NOx) st... In this investigation, Pt–Ba–Ce/c-Al2O3 catalysts were prepared by incipient wetness impregnation and experiments were performed to evaluate the influence of H2 on the evolution mechanism of nitrogen oxides (NOx) storage and reduction (NSR). The physical and chemical properties of the Pt–Ba–Ce/c- Al2O3 catalysts were studied using a combination of characterization techniques, which showed that PtOx, CeO2, and BaCO3, whose peaks were observed in X-ray diffraction (XRD) spectra, dispersed well on the c-Al2O3, as shown by transmission electron microscope (TEM), and that the difference between Ce3+ and Ce4+, as detected by X-ray photoelectron spectroscopy (XPS), facilitated the migration of active oxygen over the catalyst. In the process of a complete NSR experiment, the NOx storage capability was greatly enhanced in the temperature range of 250–350℃, and reached a maximum value of 315.3μmol·gcat^-1 at 350℃, which was ascribed to the increase in NO2 yield. In a lean and rich cycling experiment, the results showed that NOx storage efficiency and conversion were increased when the time of H2 exposure (i.e., 30, 45, and 60 s) was extended. The maximum NOx conversion of the catalyst reached 83.5% when the duration of the lean and rich phases was 240 and 60 s, respectively. The results revealed that increasing the content of H2 by an appropriate amount was favorable to the NSR mechanism due to increased decomposition of nitrate or nitrite, and the refreshing of trapping sites for the next cycle of NSR. 展开更多
关键词 Pt–Ba–Ce/c-Al2O3 CATALYSTS Physicochemical properties NOx storage and reduction emission H2 reductant
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Thermal and luminescent properties of 2 μm emission in thulium-sensitized holmium-doped silicate-germanate glass 被引量:2
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作者 Rong Chen Ying Tian +5 位作者 Bingpeng Li Xufeng Jing Junjie Zhang Shiqing Xu Hellmut Eckert Xianghua Zhang 《Photonics Research》 SCIE EI 2016年第6期214-221,共8页
In this paper, we present the luminescent properties of Tm^(3+)∕Ho^(3+)co-doped new glass. A series of silicategermanate glass was prepared by the conventional melt-quenching method. In the Tm^(3+)∕Ho^(3+)co-doped s... In this paper, we present the luminescent properties of Tm^(3+)∕Ho^(3+)co-doped new glass. A series of silicategermanate glass was prepared by the conventional melt-quenching method. In the Tm^(3+)∕Ho^(3+)co-doped silicategermanate glass, a strong emission of 2 μm originating from the Ho^(3+):~5I_7→~5I_8transition can be observed under conventional 808 nm pumping. The characteristic temperatures, structure, and absorption spectra have been measured. The radiative properties of Ho^(3+)in the prepared glass were calculated. The emission cross section of Ho^(3+)ions transition can reach 4.78 × 10^(-21)cm^2 around 2 μm, and the FWHM is as high as 153 nm. The energy transfer efficiency between Ho^(3+)and Tm^(3+)has a large value(52%), which indicates the Tm^(3+)∕Ho^(3+)co-doped silicategermanate glass is a suitable candidate for the 2 μm laser. Moreover, the energy transfer mechanism between Tm^(3+)and Ho^(3+)ions was investigated. 展开更多
关键词 Ho Tm Thermal and luminescent properties of 2 m emission in thulium-sensitized holmium-doped silicate-germanate glass
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^(99)Tc^(m)-3PRGD_(2)单光子发射计算机断层显像在大鼠乳腺癌骨移植瘤放疗疗效评价中的价值观察
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作者 张新超 胡玉敬 +4 位作者 田丛娜 魏强 赵剑 杨双臣 边艳珠 《山东医药》 CAS 2022年第29期20-23,共4页
目的观察^(99)Tc^(m)-3PRGD_(2)单光子发射计算机断层(SPECT)显像在大鼠乳腺癌骨移植瘤放疗疗效评价中的价值。方法50只Wistar大鼠通过骨髓腔内注入含有大鼠乳腺癌细胞的腹水混悬液建立胫骨移植瘤模型,最终成瘤30只。将30只乳腺癌骨移... 目的观察^(99)Tc^(m)-3PRGD_(2)单光子发射计算机断层(SPECT)显像在大鼠乳腺癌骨移植瘤放疗疗效评价中的价值。方法50只Wistar大鼠通过骨髓腔内注入含有大鼠乳腺癌细胞的腹水混悬液建立胫骨移植瘤模型,最终成瘤30只。将30只乳腺癌骨移植瘤大鼠按随机数字表法分为对照组、低剂量放疗组、高剂量放疗组各10只,分别于骨移植瘤部位行0 Gy、5 Gy、25 Gy的单次大剂量直线加速器放疗,各组分别于放疗前及放疗结束后第10天尾静脉注射^(99)Tc^(m)-3PRGD_(2),1 h后行SPECT显像并计算骨移植瘤部位放射性计数与对侧相应部位同等大小区域的放射性计数比值(T/NT)。显像结束后处死大鼠,采用HE染色观察大鼠胫骨组织病理改变,采用免疫组织化学法观察骨移植瘤组织整合素αⅤβ_(3)受体表达情况。采用Spearman相关性分析T/NT与整合素αⅤβ_(3)受体阳性细胞表达的关系。结果各组放疗前行^(99)Tc^(m)-3PRGD_(2)SPECT显像,骨移植瘤部位均可见显像剂浓聚影,浓聚程度无明显差异;各组放疗前T/NT比较无统计学差异。各组放疗后行^(99)Tc^(m)-3PRGD_(2)SPECT显像,显像剂浓聚程度对照组>低剂量放疗组>高剂量放疗组;各组放疗后T/NT对照组>低剂量放疗组>高剂量放疗组(P均<0.05)。HE染色可见各组胫骨组织均有骨结构破坏,对照组内肿瘤细胞密度高于高、低剂量放疗组,高、低剂量放疗组内有大量肿瘤细胞坏死,其中以高剂量放疗组肿瘤细胞坏死最多。对照组、低剂量放疗组、高剂量放疗组骨移植瘤组织整合素αⅤβ_(3)受体阳性率对照组>低剂量放疗组>高剂量放疗组(P均<0.05)。Spearman相关性分析显示,T/NT与αⅤβ_(3)受体阳性细胞表达呈正相关(r=0.847,P<0.01)。结论^(99)Tc^(m)-3PRGD_(2)SPECT显像指标变化与骨移植瘤病理改变一致,用于大鼠乳腺癌骨移植瘤放疗疗效评价的效果良好。 展开更多
关键词 骨移植瘤 整合素αⅴβ3受体 99Tcm-3PRGD2 单光子发射计算机断层显像 疗效评价
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Ge-S/F共掺杂对Li_(2)MSiO_(4)(M=Mn,Fe)晶体结构和性能影响的理论研究
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作者 郭厦蕾 侯育花 +2 位作者 郑寿红 黄有林 陶小马 《物理学报》 SCIE EI CAS CSCD 北大核心 2022年第17期382-392,共11页
基于密度泛函理论的第一性原理平面波赝势法,结合广义梯度近似(GGA+U),系统研究了Ge-S/F共掺杂对Li_(2)MSiO_(4)(M=Mn,Fe)晶体结构稳定性和电化学性能的影响.计算结果表明Ge-S/F共掺杂Li_(2)MSiO_(4)(M=Mn,Fe)体系在脱锂过程中均会发生L... 基于密度泛函理论的第一性原理平面波赝势法,结合广义梯度近似(GGA+U),系统研究了Ge-S/F共掺杂对Li_(2)MSiO_(4)(M=Mn,Fe)晶体结构稳定性和电化学性能的影响.计算结果表明Ge-S/F共掺杂Li_(2)MSiO_(4)(M=Mn,Fe)体系在脱锂过程中均会发生Li和M的位置交换,与Li_(2)MSiO_(4)(M=Mn,Fe)相比,掺杂体系具有更好的韧性,且锂离子在掺杂体系中更容易迁移.同时发生了位置交换的掺杂体系结构在脱锂过程中大多更为稳定,尤其是Li_(2)Mn_(0.5)Ge_(0.5)SiO_(3.5)S_(0.5)在整个脱锂过程中体积变化均很小,说明其具有良好的结构循环稳定性.此外,Ge-S/F共掺杂均降低了Li_(2)MSiO_(4)(M=Mn,Fe)的理论平均脱嵌电压.结合态密度图和磁矩结果分析表明,Ge-S/F共掺杂可以提高Li_(2)MnSiO_(4)的导电性和延缓Li_(2)MnSiO_(4)体系中Jahn-Teller效应的出现,有利于提高Li_(2)MnSiO_(4)的结构循环稳定性.同时,共掺杂不仅提高了Li_(2)FeSiO_(4)的导电性,也有利于Li_(2)FeSiO_(4)体系脱出更多的Li+,特别是Ge-F共掺杂体系有望实现完全脱锂. 展开更多
关键词 第一性原理计算 Li_(2)mSiO_(4)(m=mn Fe) 位置交换 电化学性能
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Effects of HfO_2 buffer layers on the dielectric property and leakage current of Ba_(0.6)Sr_(0.4)TiO_3 thin films by pulsed laser deposition
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作者 耿彦 程晋荣 +1 位作者 俞圣雯 吴文彪 《Journal of Shanghai University(English Edition)》 CAS 2010年第6期456-459,共4页
Ba0.6Sr0.4TiO3 (BST) thin films with and without HfO 2 buffer layer were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. Dependences of HfO 2 thickness on the dielectric property and leakage curre... Ba0.6Sr0.4TiO3 (BST) thin films with and without HfO 2 buffer layer were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. Dependences of HfO 2 thickness on the dielectric property and leakage current of BST thin films were focused. The dielectric constant of BST thin films increased and then decreased with the increase of HfO 2 thickness, while the dielectric relaxation was gradually improved. The loss tangent and leakage current under positive bias decreased with the HfO 2 thickness increasing. The leakage current analysis based on the Schottky emission indicated an improvement of the BST/Pt interface with HfO 2 buffer layer. The loss tangent, tunability and figure of merit of optimized HfO 2 buffered BST thin film achieved 0.009 8, 21.91% (E max = 200 kV/cm), 22.40 at 10 6 Hz, respectively. 展开更多
关键词 Ba0.6Sr0.4TiO3 (BST) thin film HfO 2 buffer layer dielectric property leakage current Schottky emission
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A_(7)M^(Ⅱ)RE_(2)(B_(5)O_(10))_(3)系列紫外非线性光学晶体的研究进展
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作者 何楠 公丕富 林哲帅 《人工晶体学报》 CAS 北大核心 2022年第9期1598-1607,共10页
稀土硼酸盐非线性光学(NLO)材料由于其在激光技术领域的重要应用而备受关注,这主要是因为三价稀土离子如Y^(3+)、Sc^(3+)、Lu^(3+)等可以有效抑制d-d和f-f电子跃迁从而扩宽化合物的透过范围,同时稀土原子与氧原子结合成畸变的多面体可... 稀土硼酸盐非线性光学(NLO)材料由于其在激光技术领域的重要应用而备受关注,这主要是因为三价稀土离子如Y^(3+)、Sc^(3+)、Lu^(3+)等可以有效抑制d-d和f-f电子跃迁从而扩宽化合物的透过范围,同时稀土原子与氧原子结合成畸变的多面体可增强材料的非线性光学效应。A_(7)M^(Ⅱ)RE_(2)(B_(5)O_(10))_(3)系列(RE为稀土金属,A为碱金属、M为二价金属)化合物是稀土硼酸盐中一类重要的材料,其A、M以及RE位点具备灵活的占据方式,近年来得到了广泛关注。通过化学元素取代法,研究者们对该类化合物的种类进行拓展,目前已经合成出数十种属于该体系的化合物。这些化合物的截止边大多处在紫外甚至是波长小于200 nm的深紫外波段,非线性光学效应为0.4~2.1倍KDP,在紫外以及深紫外波段非线性光学领域中展现出了应用潜力。本文对其研究现状进行了总结,分析了其微观结构与光学性能之间的关系,并指出不同位点组分对材料非线性光学性能的影响,以期对此类化合物今后的发展提供参考。 展开更多
关键词 稀土硼酸盐 A_(7)m^(Ⅱ)RE_(2)(B_(5)O_(10))_(3) 紫外/深紫外非线性光学晶体 光学性能
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Tunable emission properties of tri-doped Ca_(9)LiY_(2/3)(PO_(4))_(7):Ce^(3+),Tb^(3+),Mn^(2+) phosphors with warm white emitting based on energy transfer
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作者 Jindi Wang Riyan Su +1 位作者 Min Cui Mengmeng Shang 《Journal of Rare Earths》 SCIE EI CAS CSCD 2021年第5期504-511,共8页
Tri-doped Ca_(9)LiY_(2/3)(PO_(4))_(7):Ce^(3+),Tb^(3+),Mn^(2+)phosphors were prepared by a high-temperature solid state method.Under UV light excitation,Ca_(9)LiY_(2/3)(PO_(4))_(7):Ce^(3+)samples exhibit a broad band r... Tri-doped Ca_(9)LiY_(2/3)(PO_(4))_(7):Ce^(3+),Tb^(3+),Mn^(2+)phosphors were prepared by a high-temperature solid state method.Under UV light excitation,Ca_(9)LiY_(2/3)(PO_(4))_(7):Ce^(3+)samples exhibit a broad band ranging from 320 to 500 nm.At 77 K,the emission spectra of Ca_(9)LiY_(2/3)(PO_(4))7:Ce^(3+)samples present two obvious emission peaks,indicating that Ce^(3+)ions occupy two different kinds of lattice sites(Ca(1/2)and Ca(3)),As a good sensitizer for Tb^(3+),Ce^(3+)ions in Ca_(9)LiY_(2/3)(PO_(4))_(7)lattice can effectively transfer part of energy to Tb^(3+),and the energy trans fer mechanism is determined to be dipole-dipole interaction.Consequently,the emitting color for Ce^(3+)and Tb^(3+)co-doped Ca_(9)LiY_(2/3)(PO_(4))_(7)samples can be tuned from bluish violet to green.In order to further enlarge the emission gamut,Mn^(2+)ions as red emission components were added,forming tri-doped single-phase Ca_(9)LiY_(2/3)(PO_(4))_(7):Ce^(3+),Tb^(3+),Mn^(2+)phosphors.The Ca_(9)LiY_(2/3)(PO_(4))_(7):Ce^(3+),Tb^(3+),Mn^(2+)phosphors exhibit tunable emission properties through controlling the relative doping concentration of Ce^(3+),Tb^(3+)and Mn^(2+).Especially,Ca_(9)LiY_(2/3)(PO_(4))_(7):0.09 Ce^(3+),0.12 Tb^(3+),0.30 Mn^(2+)can emit warm white light.The sample shows good thermal stability.At 150℃,the emission intensity for Ce^(3+)(360 nm),Tb^(3+)(545 nm)and Mn^(2+)(655 nm)decreases to 63%,69%,and 72%of its initial intensity,respectively.Moreover,the sample obtains good stability after 10 cycles between room temperature and150℃. 展开更多
关键词 Ca_(9)LiY_(2/3)(PO_(4))_(7):Ce^(3+)Tb^(3+)mn^(2+) Photoluminescence properties Energy transfer White emission Rare earths
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180 m^(2)烧结机超低排放改造减排效果分析
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作者 李龙江 田梦 曹彦涛 《宽厚板》 2021年第4期35-37,共3页
为满足国家及地方有关钢铁行业超低排放改造要求,舞钢公司于2019年对180 m^(2)烧结机进行超低排放改造,项目内容包括对烧结机机头原有除尘、脱硫设施进行升级改造,并新增SCR脱硝系统,改造完成后污染物排放浓度及排放量得到显著降低,烧... 为满足国家及地方有关钢铁行业超低排放改造要求,舞钢公司于2019年对180 m^(2)烧结机进行超低排放改造,项目内容包括对烧结机机头原有除尘、脱硫设施进行升级改造,并新增SCR脱硝系统,改造完成后污染物排放浓度及排放量得到显著降低,烧结机机头烟气中颗粒物、二氧化硫、氮氧化物排放浓度分别低于5 mg/m^(3)、30 mg/m^(3)、30 mg/m^(3),颗粒物、二氧化硫、氮氧化物减排量分别为74.13 t/a、208.67 t/a、579.74 t/a。 展开更多
关键词 180m^(2)烧结机 超低排放改造 污染物减排
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