Synthesis,structural and luminescence properties of near white light emitting Dy-doped Y2CaZnO5 nanophosphor for solid state lighting

Novel near white light emitting Y₂CaZnO₅ (YCZ) nanocrystalline powders doped with Dy³⁺ ions were synthesized via the citrate gel combustion method. The structure of the compound is found to be triclinic with a particle size in the range of 20–30 nm. Luminescence properties have been characterized using photoluminescence (PL), excitation spectra and decay time measurements. The PL spectra have shown a broad blue band due to ⁴F_9/2→⁶H_15/2 transition and sharp yellow band corresponding to ⁴F_9/2→⁶H_13/2 transition of Dy³⁺ ions. From the concentration dependent PL studies, the optimum concentration of Dy³⁺ ions in YCZ is found to be 1.0 mol%, where intense near white light emission was observed. The Dy³⁺:YCZ nanophosphor has shown relatively better white color properties than the reported Dy³⁺:Y₂O₃ nanophosphor. The yellow to blue intensity ratios, CIE chromaticity coordinates and correlated color temperature studies have shown the possibility of using this compound for white light emission.     

Comparison of different methods to prepare MgO whiskers

Magnesia whiskers have been made by hydrolysis of MgCl₂–KCl melt and conversion of magnesium hydroxide whiskers. The morphology of MgO whiskers was examined by SEM and TEM. Composition of products was identified by XRD. Comparisons have been made on the morphology and quality of the products by different methods. Discussions have been made on the efficiency, product quality control and scale-up feasibility of these methods. Whiskers prepared by hydrolysis have uniform diameter but other shapes of magnesia are often found. Conversion of Mg(OH)₂ whiskers to MgO whiskers is simple and easy to scale-up, but the product often has many defects caused by decomposition. Nevertheless, the single crystal structure can be reserved as revealed by electron diffraction. XRD results show that the purity of products by hydrolysis is better than that by conversion. The conversion method is more hopeful for industrial production.     

HPLC法测定婴幼儿配方奶粉复合维生素添加剂中维生素B12方法的研究

建立了高效液相色谱法测定婴幼儿配方奶粉专用复合维生素添加剂中维生素B12 方法含量的方法。采用紫外检测器 ,波长为 36 1nm ;色谱柱为InertsilODS - 3,柱温为室温 ,流动相为磷酸二氢钠 (10g/l磷酸调pH 3.5 ) :甲醇 =70 :30 ,流速为 1.0ml/min。标准曲线回归方程y =- 0 .1340 0 .0 0 0 95 92x,相关系数为r=0 .9976 ;回收率为 96 .4 % ;12次样品重复测定变异系数为 0 .5 4 %。     

酱油曲中产纤溶酶微生物的分离筛选和初步鉴定

从生产酱油的曲中分离到产纤溶酶的米曲霉18株和枯草芽孢杆菌8株.枯草芽孢杆菌和米曲霉所产纤溶酶都含有纤溶酶原激活剂,而且对BAEE都有一定的分解作用。     

青春双歧杆菌增菌培养基的优化

针对青春双歧杆菌的营养需要 ,采用正交实验优化基础培养基及增殖因子的用量。得出最佳基础培养基配比是 :大豆蛋白胨 1 2 % ,胰蛋白胨 0 6 % ,酪蛋白水解物 0 6 % ,牛肉浸膏 0 6 % ,葡萄糖 1 % ,低聚糖 0 5 % ,乳糖 0 5 % ,酵母浸出粉 0 7%。最佳增殖因子添加量是 :胡萝卜汁 1 5 % ,番茄汁 5 % ,肝浸液 1 5 % ,胱氨酸 0 0 5 %。最后使用优化出的增菌培养基配比测定生长曲线 ,同时测定 pH和滴定酸度的变化 ,确定增菌培养终止时间为 1 2h ,通过平板菌落计数 ,此时菌数可达 2 9× 1 0 9cfu/mL。     

串行通信机床信息采集与远程监测技术研究

根据串行通信数控机床的系统功能及结构特点,阐述了这类机床的信息采集方法,并针对其中两种方法进行了验证.在此基础上,提出一种B/S模式下基于ActiveX控件的串行通信数控设备远程实时监测方法,并详细地论述了其实现过程.     

B.subtilis蛋白酶高产菌株的筛选与鉴定

本文以中性蛋白酶生产菌Ｂ．ｓｕｂｔｉｌｉｓＡＳ１．３９８为出发菌，用ＮＴＧ与紫外辐照相结合的方法对其进行复合诱变，筛选到一株蛋白酶活性明显高于出发菌的正突变株，命名为Ｂ．ｓｕｂｔｉｌｉｓＭＬ。通过对该突变株蛋白酶活性曲线的绘制、酶作用最适ＰＨ的确定、所产一的酶性质的分析及比酶活性的测定，发现该突变株扩酶活性比ＡＳ１．３９８至少高出３０％，最适反应ＰＨ７－８，酶活性受ＥＤＴＡ的强烈抑制，其突变位点很     

婴儿双歧杆菌发酵培养基组成的优化

针对婴儿双歧杆菌的营养需要,分别采用单因素试验和正交试验,优化培养基成分及用量。得出最佳发酵培养基(CPT)配比:大豆蛋白胨1.67%,酪蛋白胨0.83%,乳糖0.5%,酵母浸出粉0.5%,低聚糖0.7%,胡萝卜汁15%。最后测定婴儿双歧杆菌在发酵培养基中的生长曲线,并同时测定pH和吸光值的变化,确定发酵终止时间为12h,此时菌数可达2.18×109cfu/ml。     

人参、甘草、五味子复合醋提物对老年小鼠急性炎性肝损伤保护作用的研究

目的:本研究旨在通过脂多糖(Lipopolysaccharide,LPS)诱导肝损伤小鼠考察复合醋提物(MVE)对老年小鼠炎性肝损伤的保护效果.方法:将小鼠随机分为正常对照组、MVE组、LPS组、LPS+MVE组.通过苏木精-伊红染色评估肝组织病理情况和免疫组织化学染色判断髓过氧化物酶的表达变化.同时,检测肝组织中白介...     

米扁虫对玉米中黄曲霉毒素B1含量影响的研究

了解在非霉变和不产毒的储存条件下,原粮中昆虫对真菌毒素含量的影响具有重要生态学意义。测定了含黄曲霉毒素B1(AFB1)的玉米分别接入15、45和135头/kg米扁虫幼虫和成虫后不同存放时间AFB1含量。结果表明,米扁虫幼虫和成虫接入一定时间后均可导致玉米中AFB1含量和霉菌总数显著降低,米扁虫成虫对AFB1含量降低的作用大于幼虫,玉米破碎粒率越低时AFB1含量降低越显著,虫口密度越大、接入时间越长,AFB1含量降低越显著。