Tb3+离子在固溶体(Y0.9Gd0.1)2O2S和(Gd0.9La0.1)2O2S中的发光

用稀土氧化物硫化法合成了固溶体发光材料(Y0.9Gd0.1)2O2S:Tb和(Gd0.9La0.1)2O2S:Tb,并且用阴极射线和254nm紫外线两种激发方式测试了它们的发光性能.研究了固溶体(Y0.9Gd0.1)2O2S:Tb和(Gd0.9La0.1)2O2S:Tb中Tb3+离子5D3——7FJ和5D4——7FJ的能级跃迁强度随Tb3+离子浓度而变化的关系,以及它们的发光色度随激活剂Tb3+离子浓度的变化,探讨了Tb3+离子的浓度猝灭机理.     

La0.8Sr0.2Cr1 − xRuxO3 − δ–Gd0.1Ce0.9O1.95 solid oxide fuel cell anodes: Ru precipitation and electrochemical performance

Composites containing La_0.8Sr_0.2Cr_1 ? xRu_xO_3 ? δ (LSCrRu) with x = 0–0.25 and Gd_0.1Ce_0.9O_1.95 (GDC) were studied as anodes in solid oxide fuel cells (SOFCs) with La_0.9Sr_0.1Ga_0.8Mg_0.2O_3 ? δ (LSGM) electrolytes. Electrode polarization resistance R_P decreased during initial SOFC operation before reaching a minimum. The decrease was more rapid, and the ultimate R_P value reached was generally lower, with increasing temperature and Ru content x. R_P was stable at longer times except for x = 0.25 where it increased slightly. SOFCs with x = 0.18 anodes at 800 °C yielded power densities as high as 0.53 W/cm² with an R_P value, including the (La,Sr)(Co,Fe)O₃–GDC cathode, of < 0.15 Ω cm². Transmission electron microscopy revealed Ru nano-particles on LSCrRu surfaces; their size increased and their density decreased with increasing temperature. Increasing the Ru content increased the density of Ru surface particles at a given time and temperature. Measured early-stage Ru surface coverage values were consistent with a model where Ru supply to the LSCrRu surface was limited by Ru bulk out-diffusion, but the coverage saturated at longer times. There was surprisingly little Ru particle coarsening over times up to 1000 h at 800 °C, with Ru particles sizes remaining < 10 nm. The cell R_P values generally decreased with increasing Ru nano-particle surface area.     

Er0.1La0.9P5O14非晶的双光子上转换发光

本文研究了全浓度ＥｒＬａＰ５Ｏ１４非晶在波长λ为６４９．０ｎｍ脉冲染料激光激发下的上转换发光现象，并对其进行了简要的分析。     

Synthesis, Crystal Structure and Luminescent Property of Complex [Tb0.1Gd0.9(TPTZ)(H2O)6]Cl3·3H2O

The complex [Tb_0.1Gd_0.9(TPTZ)(H₂O)₆]Cl₃·3H₂O was prepared through the reaction of 2,4,6-tris-(2-pyridyl)-1,3,5-triazine (TPTZ) with TbCl₃:GdCl₃ (0.1:0.9) in absolute ethanol at room temperature. Single crystal X-ray diffraction revealed that the metal atom is nine-coordinated with three nitrogen atoms from one TPTZ ligand and six oxygen atoms from six water molecules. The complex emits intense green fluorescence under ultraviolet light. The luminescence peaks correspond to the characteristic emission ⁵D₄→⁷F_J (J = 3–6) transitions of the Tb³⁺ ion.     

单相Bi0.9Ba0.1Fe0.85Mn0.15O3陶瓷中的多铁性

溶胶-凝胶法制备了Bi0.9Ba0.1Fe0.85Mn0.15O3陶瓷样品,XRD分析显示其为单相菱方钙钛矿结构,明显的磁滞回线和电滞回线说明其在室温具有弱铁磁性和铁电性,介电常数随外磁场的变化显示双掺样品具有更大的磁容效应.     

Tb0.3 Dy0.7(Fe0.9 T0.1)1.95合金的结构、自旋重取向和穆斯堡尔谱

系统研究了室温下Tb0.3Dy0.7(Fe0.9T0.1195(过渡金属元素T=Mn,Fe,Co,B,Al,Ga)合金中ⅢA族金属和过渡金属元素T替代Fe对结构、自旋重取向和穆斯堡尔谱的影响.结果发现,不同金属T替代Fe,Tb0.3Dy0.7(Fe009T0.11.95,合金具有相同的MgCu2型立方Laves相结构;Al,Ga替代使Tb0.3Dy0.7(Fe09T0.11.95合金的易磁化方向在{110}面逐渐偏离了立方晶体的主对称轴,即自旋重取向,B,Mn,Co替代未使易磁化轴发生明显转动;Al,Ga元素替代使超精细场Hhf略有下降,B,Mn替代对超精细场Hhf的影响不大,而Co元素替代使超精细场Hhf有较大增加;所有元素替代使同质异能移IS有所增加;B,Al,Ga和Mn替代使四极劈裂Qs增加,而Co替代使四极劈裂Qs下降.     

（Gd,Y）P5O14：Ce,Tb中Gd的中介能量传递和传递几率计算

研究了稀土五磷酸盐ＧｄｘＹ１－ｘ）Ｐ５Ｏ１４：Ｃｅ０．０１，Ｔｂ０．０２体系中以Ｇｄ＾３＋子晶格为中介的Ｃｅ＾３＋→Ｇｄ＾３＋→Ｔｂ＾３＋的能量传递现象。当ｘ＞０．７，在室温下激发Ｃｅ＾３＋离子可以产生有效的Ｔｂ＾３＋的发光。对ｘ＝１和０时，激发Ｃｅ＾３＋产生Ｔｂ＾３＋的发光，前者的强度约为后者的１０倍。     

Diode-pumped passively mode-locked femtosecond Yb：（Y0.9La0.1）2O3 ceramic laser

We experimentally demonstrate a diode-pumped passively mode-locked femtosecond laser with Yb 3+ -doped yttrium lanthanum oxide ceramic. Mode-locking is achieved by using a semiconductor saturable absorber mirror, and intracavity dispersion is compensated by a pair of SF6 prisms. Laser pulses as short as 357 fs at a central wavelength of 1 075 nm are obtained. The maximum average output power is 670 mW under 4.5 W of pumping power with a slope efficiency of 20%. To the best of our knowledge, this is the shortest pulse generated from Yb-doped yttrium lanthanum oxide ceramic lasers with a sub-500 fs pulse duration.     

(Ce,Gd,Mn)MgB5O10磷光体的合成及其发光

本文采用固相反应的方法合成了一系列(Ce,Gd,Mn)MgB5O10磷光体。观察到合成温度、灼烧时间、原料配比对磷光体的形成和发光亮度有重要影响。X射线衍射分析表明,磷光体结构与LaMgB5O10相同,属单斜晶系、空间群P21/c。用EPR确定了磷光体中锰离子为二价。测定了(Ce0.2La0.2)MgB5O10,(Gd0.7La0.3)MgB5O10,(Mn0.05La0.95)MgB5O10,(Ce0.2Mn0.05La0.75)MgB5O10,(Gd0.95Mn0.05)MgB5O10、(Ce0.2Gd0.8)MgB5O10和(Ce0.2Gd0.75Mn0.05)MgB5O15等磷光体的光谱。根据光谱数据讨论了(Ce0.2Gd0.75Mn0.05)MgB5O10磷光体中能量传递过程为:Ce3+→Mn2+,Gd3+→Mn2+以及Ce3+→Gd3+→Mn2+,其中Ce3+离子可将能量高效地传递给Gd3+,Gd3+离子起着中间体的作用。     

La0.9Na0.1MnO3的反常超声特性

系统地测量了La0.9Na0.1MnO3单相陶瓷样品的电阻、磁化率、超声声 速和衰减随温度的变化关系，发现在245K附近体系发生顺磁绝缘体－铁磁金属相变，同时超声声速出现剧烈的软化现象，其相对变化超过2％。超声衰减也出现一个尖锐的衰减峰。经分析认为这些发生在Curie温度附近的反常超声现象，可能是由自旋－声子和电－声子相互作用共同引起的。     

Investigation of Ce0.9Sr0.1Cr0.5Co0.5O3−δ as the anode material for solid oxide fuel cells fueled with H2S

Ce_0.9Sr_0.1Cr_0.5Co_0.5O_3?δ (CSCrCo) as an anode catalyst was studied in a solid oxide fuel cell (SOFC), where hydrogen sulfide (H₂S) was used as fuel. The conductivities were evaluated with a four-probe DC technique in 3 % H₂-N₂ and 5 % H₂S-N₂ at 570–800 °C, respectively. X-ray diffraction (XRD) patterns show that CSCrCo powders are fluorite structure which is similar to that of CeO₂ parent (JCPDS card no. 34-0394). Meanwhile, CSCrCo anode material has good chemical compatibility with electrolyte (Ce_0.8Sm_0.2O_1.9 (SDC)) in N₂. Through the analysis of XRD and Fourier transform infrared patterns, no other new phase is detected after treatment in 5 % H₂S-N₂ at 800 °C for 5 h, which indicate that the material has a good sulfur tolerance. H₂ temperature-programmed reduction and Tafel curves indicate that the temperature of the best catalytic activity is 600 °C. The electrochemical properties of the cell comprising CSCrCo-SDC/SDC/Ag are measured in 5 % H₂S-N₂ at low temperatures (500 and 600 °C). The maximal open circuit voltage is 1.04 V, the maximal power density is 12.55 mW cm^?2, and the maximal current density is 40 mA cm^?2 at 500 °C. While at 600 °C, the corresponding values are 0.95 V, 14.21 mW cm^?2, and 90.01 mA cm^?2, respectively. After SOFC operating in 5 % H₂S, X-ray photoelectron spectroscopy is used to compare the fresh sample with the H₂S-treated one.     

Photoelectric Characteristic of La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 p-n Heterojunctions

Good rectifying current-voltage characteristics and nanosecond photoelectric effects are observed in the p-n hereto junctions of La0.9Sr0.1 MnO3/SrNb0.01 Ti0.99O3 fabricated by laser molecular beam epitaxy. The rise time is about 26ns and the full width at half maximum is about 125ns for the open-circuit, photovoltaic pulses when the La0.9Sr0.1MnO3 film in the heterojunction is irradiated by a laser operated at wavelength 308nm with pulse duration of about 25 ns. A qualitative explanation is presented, based on an analysis of the photoelectric effect of p-n hereto junction.     

Influence of Self-Absorption and Impurities on Scintillation Properties of （Lu0.1Y0.9）A103：Ce Single Crystals

Lu0.1Y0.9AlO3：Ce single crystals in dimensions Φ30×90 mma are successfully grown by the Czochralski method. The light output and energy resolution of the crystal in dimensions Φ14×2mm^3 are 9420 photons/MeV and 12.5% respectively. Dependence of the light output on the thickness of the sample is found and explained by the self-absorption in the range of 320-370nm and the underlying parasitic absorption around 250hm. In addition, the local enrichment of Ce ions and the presence of low-valent impurity ions may cause the deterioration of its light output. In addition, Lu0.1 Y0.9AlO3：Ce has an almost constant fluorescence decay time of 16ns in the temperature range of 80-373 K.     

Spin Glass Behaviour and Spin-Dependent Scattering in La0.7Ca0.3Mn0.9Cr0.1O3 Perovskites

The magnetic, electrical and thermal transport properties of the perovskite La0.7Ca0.3Mn0.9 Cr0.1O3 have been investigated by measuring dc magnetization, ac susceptibility, the magnetoresistance and thermal conductivity in the temperature range of 5-300 K. The spin glass behaviour with a spin freezing temperature of 70 K has been well confirmed for this compound, which demonstrates the coexistence and competition between ferromagnetic and antiferromagnetic clusters by the introduction of Cr. Colossal magnetoresistance has been observed over the temperature range investigated. The introduction of Cr causes the ““double-bump““ feature in electrical resistivity ρ(T). Anomalies on the susceptibility and the thermal conductivity associated with the double-bumps in ρ(T)are observed simultaneously. The imaginary part of ac susceptibility shows a sharp peak at the temperature of insulating-metallic transition where the first resistivity bump was observed, but it is a deep-set valley near the temperature where the second bump in ρ(T) emerges. The thermal conductivity shows an increase below the temperature of the insulating-metallic transition, but the phonon scattering is enhanced accompanying the appearance of the second peak of double-bumps in ρ(T). We relate those observed in magnetic and transport properties of La0.7Ca0.3Mn0.9Cr0.1O3 to the spin-dependent scattering. The results reveal that the spin-phonon interaction may be of more significance than the electron (charge)-phonon interaction in the mixed perovskite system.     

La0.9Sr0.1MnO3薄膜中电流效应研究

用直流磁控溅射法在(100)LaAlO3衬底上制备了La0.9Sr0.1MnO3薄膜.经退火处理后薄膜的原子力显微镜形貌观测和X射线衍射分析显示具有比较好的质量.电阻率-温度关系表明La0.9Sr0.1MnO3薄膜在281 K处发生金属绝缘体转变.电流在0.01-4 mA范围内,薄膜的峰值电阻率随电流增大而减小,在4 mA下获得了30.5%的峰值电阻率变化率,并从相分离图像给出了简单解释.     

Nd0.9Ca0.1Ba2Cu3O6＋x超导体系的红外光谱研究

用固相反应法制备、并通过没条件的热处理得到了一组同氧含量的Ｎｄ０．９Ｃｄ０．１ｂａ２Ｃｕ３Ｏ６＋ｘ样品。用Ｘ射线衍射确定了样品的相结构。随着氧含量的增大，结构发生从四方到正交相变。进一步用红外吸收谱研究了体系的结构变化特征。谱图上６４２ｃｍ＾－１，５７８ｃｍ＾－１，５３８ｃｍ＾－１峰的出现及位移，与氧含量引起的结构变化是一致的，并讨论结构与超导电性的关系。