Red-shift and improved afterglow of Sr3Al2-xBxO5Cl2:Eu2+, Dy3+ phosphors via a cation substitution strategy

Sr₃Al_2-xB_xO₅Cl₂:Eu²⁺, Dy³⁺ (x = 0, 0.2, 0.4) long persistent phosphors were prepared via solid-state process. The pristine Sr₃Al₂O₅Cl₂:Eu²⁺, Dy³⁺ phosphor exhibits orange/red broad band emission around 609 nm, which can be attributed to the electric radiation transitions 4f⁶5 d¹→4f⁷ of Eu²⁺. Upon the same excitation, the B³⁺-doped Sr₃Al_2-xB_xO₅Cl₂:Eu²⁺, Dy³⁺ phosphors display red-shift from 609 nm to 625 nm with increasing B³⁺ concentrations. The XRD patterns show that Al³⁺ can be replaced by B³⁺ in the host lattice at the tetrahedral site, which causes lattice contraction and crystal field enhancement, and thereafter achieves the red-shift on the emission spectrum. The XPS investigation provides direct evidence of the dominant 2-valent europium in the phosphor, which can be ascribed for the broad band emission of the prepared phosphors. The afterglow of all phosphors show standard double exponential decay behavior, and the afterglow of Sr₃Al₂O₅Cl₂:Eu²⁺, Dy³⁺is rather weak, while the sample co-doped with B³⁺shows longer and stronger afterglow, as confirmed after the curve simulation. The analysis of thermally stimulated luminescence showed that, when B³⁺ is introduced, a much deeper trap is created, and the density of the electron trap is also significantly increased. As a result, B³⁺ ions caused redshift and enhanced afterglow for the Sr₃Al_2-xB_xO₅Cl₂:Eu²⁺, Dy³⁺ phosphor.     

ZL101合金锶变质效果及热处理工艺的改进

对现场生产的ZLl01合金铸件材质进行了全面分析，针对存在的产品成分不准，变质效果不好，力学性能不合格的问题，通过改进合金的锶变质工艺和热处理工艺，改善了合金的组织和性能，达到了对材料的成分、性能的各项要求。     

烧成及热处理工艺对钛酸锶铅基热敏材料性能及显微结构的影响

研究了烧成及热处理工艺对钛酸锶铅基热敏材料的阻温特性及显微结构的影响。通过扫描电镜（ＳＥＭ）和能量分散仪（ＥＤＡＸ）分析了材料的显微结构及不同形貌晶粒的成份。通过对组成、烧成及热处理工艺的控制，可得到具有Ｖ型ＰＴＣＲ特性的热敏材料。     

Effect of Bi and Sr concentrations on the formation of the 2223 phase in Bi-Pb-Sb-Sr-Ca-Cu-O materials, obtained under different conditions of thermal treatment

The superconducting properties and the phase and chemical composition of Bi _x Pb_0.3Sb_0.1Sr _y Ca₂Cu₃O_z (x=1.5, 1.6, and 1.7;y=1.9, 2.0, and 2.1) materials synthesized by one-step and multistep thermal treatments have been investigated. The multistep annealing between 825–875°C promotes the 2223 phase. The change of Bi concentration has little effect on the 2223 phase formation, regardless of the kind of thermal treatment used, but increasing the Sr concentration (y> 2) strongly inhibits this phase. It has also been established that the loss of Pb after synthesis depends on the initial Bi concentration. The loss of Pb decreases when the initial Bi content is lower.     

Experimental investigation and thermodynamic modeling of the Mg–Sn–Sr ternary system

The isothermal sections of the Mg–Sn–Sr ternary system in the Mg-rich region at 415 and 350 °C have been determined using the scanning electron microscopy (SEM) equipped with energy dispersive X-Ray spectrometry (EDS). The existence of the MgSnSr ternary compound was confirmed in these two isothermal sections. Two new compounds, named Mg₅Sn₃Sr and Mg₂₅Sn₂₄Sr_14, were found in the present work based on the SEM/EDS results. Thermodynamic optimization of the Sn–Sr binary and Mg–Sn–Sr ternary systems were carried out using the CALPHAD (CALculation of PHAse Diagrams) technique. The Modified quasi-chemical model (MQM) was used for the liquid solution which exhibits a high degree of short-range ordering behavior. The solid phases were described with the Compound energy formalism (CEF). Finally, a self-consistent thermodynamic databases for the Mg–Sn–Sr ternary system has been constructed in the present work, which can be an efficient and convenient guidance to investigate and develop the Mg-based alloys.     

MODIFICATION EFFECT OF Sr ON Al-Si ALLOY

本文采用引入单晶Si籽晶的方法,考察Sr变质Al-22％Si合金中Si相的生长行为。结果表明Sr影响Si相的形核与生长。表面分析指出Sr在{111}_(Si)上的吸附是Sr影响Si相形核生长的原因,而变质共晶组织则是Sr使共晶领先相发生改变的结果。     

La0.6Sr0.4Co1-yFeyO3钙钛矿复合氧化物的结构与电学性能

采用固相反应法合成出La0.6Sr0.4Co1-yFeyO3体系复合氧化物样品，XRD分析结果证实不同Co／Fe比例的样品中均形成菱形六面体钙钛矿结构，采用固相烧结法制备出致密的La0.6Sr0.4Co1-yFeyO3体系陶瓷。研究结果表明，在室温到900℃温度范围内La0.4Sr0.4CoO3(y=0)的电导率随温度的增加而单调降低，其它Co／Fe比例样品的电导率随着温度的增加出现最大值，电导率达到最大值的温度随Co／Fe比例的降低而提高。在低温段，La0.6Sr0.4Co1-yFeyO3体系的导电行为符合小极子导电机制，导电活化能随Co／Fe比例的降低而增加。     

Oxygen transport in ferrite-based ceramic membranes: Effects of alumina sintering aid

Moderate additions of Al₂O₃ to strontium ferrite-based mixed conductors, such as SrFe_0.7Al_0.3O_3−δ and La_0.2Sr_0.8Fe_0.8Ga_0.2O_3−δ with the composition close to the solid solution formation limits, make it possible to improve ceramics sinterability, to increase oxygen permeability and to decrease thermal expansion. These effects are associated with the segregation of alumina-rich phases, primarily SrAl₂O₄, and the formation of A-site cation-deficient perovskite. The improved properties of the SrFe_0.7Al_0.3O₃-based material were used to fabricate high-quality tubular membranes for methane conversion reactors. Similar enhancement in sinterability is also observed for another promising parent material of mixed-conducting membranes, La_0.5Sr_0.5FeO_3−δ. However, extensive dissolution of Al³⁺ cations in the iron sublattice, creation of A-site vacancies and changing the La:Sr concentration ratio all lead to decreasing ionic transport in La_0.5Sr_0.5FeO_3−δ. As a result, additions of either Al₂O₃ or SrAl₂O₄ have a deteriorating influence on the oxygen permeation fluxes through La_0.5Sr_0.5FeO₃-based ceramics.     

累托石对模拟核素Sr~(2+)、Cs~+、Co~(2+)的吸附性能研究

分析湖北钟祥杨榨累托石矿床的累托石土样的基本物化特性的基础上,进行了累托石对模拟核素Sr2+、Cs+、Co2+的静态吸附性能的研究。实验表明,累托石的阳离子交换容量(CEC)为36.04 mmol/100 g,胀缩度为23.89%,渗透系数为6.94×10-8cm/s。在中性条件下,累托石对模拟核素Sr2+、Cs+、Co2+的平衡吸附量分别为70,48,20 mg/g。累托石对核素的吸附量会随着吸附时间的增加而逐渐趋于稳定。弱碱性条件下累托石的吸附效果更好。