烧结温度对蓝色长余辉材料Sr_2Al_6O_(11):Eu~(2+),Dy~(3+)发光性能的影响

采用传统的高温固相法合成了蓝色长余辉发光材料Sr_2Al_6O_(11)∶Eu~(2+),Dy~(3+),系统研究了烧结温度对Eu~(2+)和Dy~(3+)共掺杂蓝色铝酸锶长余辉材料物相及发光性能的影响.用X射线衍射仪对所合成的材料进行物相分析,用荧光分光光度计记录了样品的激发光谱和发射光谱,用亮度计记录其余辉衰减曲线.结果表明:随着烧结温度从1100 ℃升高到1300 ℃,材料的物相由富锶相逐渐向富铝相转变,其中1200 ℃条件下合成的样品主相为Sr_2Al_6O_(11);发射光谱首先发生蓝移,随后又发生红移,其中1200 ℃条件下合成的样品发射光谱峰值波长最短(468 nm);主相为Sr_2Al_6O_(11)的蓝色铝酸锶长余辉材料的余辉时间(≥1 mcd/m2)可达240 min以上.     

NSB对油菜某些生理特性及产量的影响

在油菜的蕾苔期、初花期喷施一定浓度的植物生长调节剂萘乙酸、微量元素锶和硼的混合配方,可以促进植物的生长发育和增强花粉的生活力,提高泌蜜量、叶绿素含量和硝酸还原酶的活性,增强植株的根系活力和抗旱性,加快可溶性糖的转移,同时能有效地提高油菜产量。     

锶改性对γ-Al2O3的高温热稳定作用

 研究了Sr（NO3）2浸渍改性对γ－Al2O3的高温热稳定作用,考察了Sr含量（SrO／Al2O3摩尔比为0．005～0．15）以及热处理温度（600～1150℃）和气氛等影响因素．BET比表面积和粉末X射线衍射结果表明,高温下Sr物种的引入明显地抑制了氧化铝比表面积的损失和α相变,而水蒸气的存在则削弱了Sr物种的高温稳定作用．随着Sr含量的增大,Sr物种的高温稳定作用增强,但过度提高Sr含量时（SrO／Al2O3比为0．15）,Sr物种的纯机械混合掺杂的负作用超过其对Al2O3的稳定作用．焙烧温度从600℃升至1150℃,氧化铝与Sr物种固相反应的产物由二铝酸盐转化至六铝酸盐．高温动力学研究结果表明,Sr的高温稳定作用主要是抑制焙烧过程中最初1h内的烧结和其后α相变引起的比表面积损失．     

火焰原子吸收光谱法测定铝酸钠溶液中微量铷

采用空气－乙炔火焰原子吸收光谱法测定铝酸钠溶液中微量铷。对仪器工作条件、测定体系酸度、共存离子干扰等作了研究。方法用于氧化铝生产工艺中碳分、种分、蒸发母液及类似样品中微量铷的快速分析。方法准确度较高,结果重现性好。     

铝酸钠溶液的鲁米诺增强声致发光研究

Ultrasonic processing on sodium aluminate solutions was proved to have effects on the gibbsite crystallization process from sodium aluminate solution. In order to investigate the mechanism of the ultrasonic intensification, the sonofluorescence spectrum was detected by fluorescence spectrometer in sodium alumiante Luminol solutions, and the spectrum under the conditions of various ultrasonic power and different composition of sodium aluminate solutions were studied. It is found that the sodium aluminate Luminol solution can irradiate fluorescence by ultrasonic processing above the given power; the intensity of sonofluorescence are relatively low in sodium aluminate solutions with high concentration and low αk（mol ratio of Na2O/Al2O3 in sodium aluminate solution）. The relationship between the sonofluorenscence and ultrasonic intensification on gibbsite crystallization process from sodium aluminate solutions were also discussed. The conclusion that the ultrasonic effects are influenced by ultrasonic cavitation and intensity of sonofluorescence spectrum is deduced.     

Quasilinear Molecule par Excellence,SrCl2: Structure from High‐Temperature Gas‐Phase Electron Diffraction and Quantum‐Chemical Calculations—Computed Structures of SrCl2×Argon Complexes.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.     

溶剂浮选-气相色谱法测定铝酸钠溶液中的硬脂酸钠

用溶剂浮选-气相色谱法测定铝酸钠溶液中的硬脂酸钠。选择环己酮为浮选溶剂,样品经1∶1(V/V)的盐酸酸化后,以40 mL/m in的速度通入氮气并以环己酮为浮选溶剂浮选30 m in进行富集,用CH3OH/BF3在80℃水浴中加热3 m in进行甲酯化,以毛细管色谱柱PEG-20M(30 m×0.32 mm,i.d.)分离,邻苯二甲酸二乙酯为内标,氢火焰离子化检测器检测。方法在硬脂酸与内标的质量比在0.1~10范围内呈良好的线性关系(r=0.9997);硬脂酸钠的相对标准偏差为1.35%(n=7);回收率为96.9%~98.1%。     

燃烧法合成铝酸盐发光粉的研究

利用金属硝酸盐和尿素发生的氧化还原反应，制备了发绿光的铝酸盐发光粉Ｃｅ０．６７Ｔｂ０．３３ＭｇＡｌ１２Ｏ２０．５．反应在６００℃下完成．对产物的性质进行了表征和研究．考察了尿素用量，炉温及其它制备条件对发光粉的性质，特别是亮度的影响     

Studies of the structure of Ce3+ centers in SrS phosphors

It is found that the shape of luminescence spectra of SrS−Ce phosphors is independent of both the species and concentration of a cofactor F, Cl, Br, or 1 introduced in the form of ammonium halide at least up to 6.5 at.%. The only exception is F, which, when added as a coactivator with a concentration of 2.4 at.% and above, gives rise to new longwave luminescence bands, part from the luminescence of the Ce³⁺ ion. Analysis has shown that this additional luminescence spectrum is similar to the Ce³⁺ spectrum but is shifted towards the longwave region by about 0.14 eV. The luminescence decay time constant (τ=57 nsec) is very close to Br, I, and small concentrations of F, a model is valid according to which the halogen that substitutes for sulfur and the Ce³⁺ that substitutes for Sr are the closest neighbors not to each other, but to a probable compensator of the charge of Sr vacancies. At high concentrations of fluorine some of the F ions are located at interstitial lattice sites in the immediate neighborhood of Ce³⁺, providing compensation for the charge of Ce³⁺ ions and having a marked effect on them. Tartu University, 18, Ulikooli St., Tartu EE2400, Estonian Republic. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 2, pp. 173–178, March–April, 1997.     

(Sr,Co,Nb）掺杂SnO2压敏电阻的电学非线性

研究了Sr对新型(Co, Nb)掺杂SnO₂压敏材料微观结构和电学性质的影响.当SrCO ₃的含量从零增加到1.50mol%时，(Co, Nb)掺杂SnO₂压敏电阻的击穿电压从240V/mm猛增 到1482V/mm.样品的微观结构分析发现, 当SrCO₃的含量从零增加到1.50 mol%时, SnO2的晶粒尺寸迅速减小．晶界势垒高度测量揭示，SnO₂晶粒尺寸的迅速减小是击穿 关键词： 碳酸锶 二氧化锡 势垒 电学非线性