硼酸铝晶须增强Al复合材料的性能及界面结构

采用挤压铸造工艺制备出复合良好的9Al_2O_3 2B_2O_3晶须增强6061Al合金及纯Al复合材料研究表明,T6处理不能提高9Al_2O_3 2B_2O_3w/6061Al复合材料的力学性能,其原因是T6处理后复合材料中的界面反应明显加重利用透射电子显微术对此复合材料界面的观察与分析认为,界面上存在着严重的化学反应,反应物为Al_2MgO_4将制造态与T6态的界面结构对比发现,正是这种界面化学反应对材料的性能产生不利影响而在9Al_2O_3 2B_2O_3w/纯Al界面上未发现任何化学反应。界面能谱EDS成分分析结果表明,上述界面化学反应是由材料制造过程中基体合金中的Mg在界面上原子偏聚造成的     

Spectroscopic analysis of a novel Nd3+-activated barium borate glass for broadband laser amplification

Spectroscopic parameters of a novel Nd³⁺-activated barium borate (BBONd) glass have been analyzed for broadband laser amplification. The Judd–Ofelt (JO) intensity parameters were determined through a systematic analysis of the absorption spectrum of Nd³⁺ ions in the BBONd glass. High values of the JO intensity parameters reveal a great centro-symmetrical loss of the Nd³⁺ sites and high covalency degree of the ligand field. The very high Ω₆ intensity parameter value makes evident both a great structural distortion of the Nd³⁺ sites and a strong electron–phonon coupling between Nd³⁺ and free OH⁻ ions, which is consistent with the phonon energy maximum (3442.1 cm⁻¹) recorded by Raman spectroscopy. This strong electron–phonon coupling favors high effective bandwidth and gain bandwidth values of the laser emission (⁴F_3/2 → ⁴I_11/2) of Nd³⁺ ions. The electric-dipole oscillator strengths of all the Nd³⁺ absorption transitions, and in particular that of the hypersensitive transition (⁴I_9/2 → ⁴G_5/2), are enhanced by this great structural distortion of the host. Broadband laser amplification of the ⁴F_3/2 → ⁴I_11/2 emission (1062 nm) of Nd³⁺ ions in the BBONd glass pumped at 805 nm (⁴I_9/2 → ⁴F_5/2 + ²H_9/2) is evaluated through the main fluorescent parameters in competition with non-radiative processes. In general, the BBONd glass exhibits spectroscopic parameters comparable with those reported in the literature for broadband laser amplification into the IR region.     

用三氟化硼乙醚络合物合成硼酸三甲酯

试验研究了常压下,在甲醇介质中,用甲醇钠与三氟化硼乙醚络合物反应制备硼酸三甲酯的工艺流程,并探索其最佳工艺条件.结果利用气相色谱、色谱-质谱联用、红外光谱等分析表征手段,鉴定反应产物确实是硼酸三甲酯.并摸索其最佳工艺条件为：反应温度55℃;回流时间32 h.然后分馏,收集硼酸三甲酯甲醇恒沸物.最后用LiCl盐析法提纯硼酸三甲酯,得到硼酸三甲酯的含量在99%以上.     

新型生料乳浊釉的研制

通过引入合成硼酸锌及活化处理锆英石粉制备了烧成温度低、乳浊度高的生料乳浊釉,并讨论了硼酸锌及锆英石粉活化处理对乳浊釉性能的影响。     

Al18B4O33 aluminium borate: A new efficient support for palladium in the high temperature catalytic combustion of methane

Well crystallised aluminium borate Al₁₈B₄O₃₃ has been synthesised from alumina and boric acid with a BET area of 18 m²/g after calcination at 1100 °C. Afterwards, 2 wt.% Pd/Al₁₈B₄O₃₃ was prepared by conventional impregnation of Pd(NO₃)₂ aqueous solution and calcination in air at 500 °C. The catalytic activity of Pd/Al₁₈B₄O₃₃ in the complete oxidation of methane was measured between 300 and 900 °C and compared with that of Pd/Al₂O₃. Pd/Al₁₈B₄O₃₃ exhibited a much lower activity than Pd/Al₂O₃ when treated in hydrogen at 500 °C or aged in O₂/H₂O (90:10) at 800 °C prior to catalytic testing. Surprisingly, a catalytic reaction run up to 900 °C in the reaction mixture induced a steep increase of the catalytic activity of Pd/Al₁₈B₄O₃₃ which became as active as Pd/Al₂O₃. Moreover, the decrease of the catalytic activity observed around 750 °C for Pd/Al₂O₃ and attributed to PdO decomposition into metallic Pd was significantly shifted to higher temperatures (820 °C) in the case of Pd/Al₁₈B₄O₃₃. The existence of two distinct types of PdO species formed on Al₁₈B₄O₃₃ and being, respectively, responsible for the improvement of the activity at low and high temperature was proposed on the basis of diffuse reflectance spectroscopy and temperature-programmed desorption of O₂.     

硼酸铝晶须的应用与制备

无机材料在国民经济和国防建设中均占有重要地位，其中硼酸铝晶须作为一种新型的无机应用材料，由于其具有许多的特殊功能，而且相对廉价，近年来受到了人们的广泛关注。就硼酸铝晶须的组成、物化性能及主要用途作了简单介绍，并主要介绍了生产硼酸铝晶须两种主要方法——助熔法和水热法。指出与发达国家相比，中国在这方面的研究工作还有很大差距，今后如能大力开展制备和应用方面的研究，中国的许多工程材料的性能将得到极大的提高。     

Fe3O4颗粒对硼酸铝晶须增强铝复合材料热膨胀行为的影响

硼酸铝晶须增强铝复合材料中加入Fe3O4颗粒可以降低该复合材料的热膨胀系数．研究认为复合材料中Fe3O4颗粒在制备过程中部分被氧化,在热膨胀测试过程中被氧化的Fe3O4又被还原,其体积将变小,基体铝的膨胀受到限制,相当于具有负膨胀系数性质,从而起到了降低复合材料热膨胀系数的作用．结合复合材料中Fe3O4磁场热重曲线分析,阐述了颗粒的残余应力在热循环中的变化情况．     

阿奇霉素合成中硼酸酯水解的研究

对阿奇霉素合成中的两种硼酸酯,即阿奇霉素硼酸酯(AZMB)及其前体氮红霉素硼酸酯(AZAB)的水解进行了比较,AZAB的最佳水解条件为:pH=3.0、水解温度30℃、水解时间30 m in,转化率91.9%;AZMB的水解条件为:pH=2.0,温度30℃、反应时间90 m in,转化率为89.3%。实验表明,AZAB比AZMB更易水解。采用有机酸和无机酸的混合酸代替文献[6]中的无机酸调节水解的pH,可以抑制克拉定糖的酸性降解反应。通过改进后,以红霉素6,9-亚胺醚为原料,阿奇霉素二水化合物的总收率可以达到85%,经HPLC分析,质量分数为98.4%。     

Eu~(2+)激活的蓝光荧光粉研究进展

介绍了蓝光荧光粉的类型(主要为碱土铝酸盐型BaMgAl10O17,硅酸盐型,磷酸盐型及其硼酸盐型蓝光发光材料)及结构,总结了其研究现状与发光机制,概括了常规制备方法,指出了蓝光荧光粉存在的问题和今后研究与应用的方向。