Sol-Gel Synthesis and Luminescence of Green Light Emitting Phosphors Zn2SiO4/Mn^2＋     

赵林阎晓敏  邵建辉 《天津大学学报(英文版)》2006,12(1):33-36

MN2 DOPED ZN2SIO4 PHOSPHORS WERE SYNTHESIZED BY SOL-GEL METHOD, AND THE INFLUENCE OF ZINC SOURCE. MN2 DOPANT CONCENTRATION AND ANNEALING TEMPERATURE WERE INVESTIGATED. RESULTS SHOW THAT ZINC NITRATE BASED PRECURSOR WITH STRONG GREEN EMISSION INTENSITIES IS BETTER THAN ZINC ACETATE BASED PRECURSOR. THE INTENSITY OF GREEN LIGHT EMISSION REACHES A PEAK AT 254 NM WHEN THE MN2 DOPANT CONCENTRATION IS ABOUT 5%( MOLAR PERCENTAGE). STRUCTURAL DETAILS OF THE PHOSPHORS WERE EXAMINED THROUGH X-RAY DIFFRACTOMETRY. THERMOGRAVIMETRIC AND DIFFERENTIAL THERMAL ANALYSIS. THE RESULT INDICATES THAT THEY ARE BOTH RHOMBOHEDRAL STRUCTURES, WHICH REMAIN AMORPHOUS BELOW 700 ℃ AND CRYSTALLIZE COMPLETELY AROUND 1 000 ℃. THE LUMINESCENT PROPERTIES OF ZN:SIO4/MN2 PHOSPHORS WERE CHARACTERIZED BY EXCITATION AND EMISSION SPECTRA.  相似文献   

带强迫项对流系统的空间混沌定义     

胡晓珊 《德州学院学报》2004,20(6):90-93

主要研究了一类二维离散动力系统(2-D),即带强迫项对流系统的空间混沌行为,介绍了连续对流系统在Li-Yorkc和Marotto意义下的空间混沌定义以及非连续对流系统(分段连续对流系统)在转数区间意义下的空间混沌定义,并且分析了它的空间混沌的存在性.  相似文献   

Hg_2Br_2声光器件换能器的频率特性     

谢本亮  卢于辉 《赣南师范学院学报》2003,(3):27-31

提出用环氧树脂聚合物作为换能器与Hg2Br2声光介质的缓冲层(粘接层),设计Hg2Br2声光器件的换能器三层和五层结构.根据换能器等效电路网络分析法,就x切LN/Hg2Br2声光器件三层结构和五层结构的损耗TL随规一化频率f/f0的变化关系及相应结构下输入阻抗与规一化频率f/f0的变化关系进行了计算并给出了结果.  相似文献   

Research on Gelcasting Formation of SiC-Al_2O_3-Y_2O_3-La_2O_3 Systems     

郭文利  徐廷献  靳正国 《天津大学学报(英文版)》2003,9(3)

Siliconcarbide (SiC)ceramicmaterialsareusefulad vancedmaterialsinmanyfields,suchasmedicalbiomateri als ,hightemperaturesemiconductors ,synchrotronopticalel ementsandhighstrength /lightweightstructuralmaterials[1] .However,theactualapplicationisstilllimitedduetoitslowreliability ,highmachiningcosts[2 ] .Gelcastingprovidesane conomicalandfeasiblenet shape forminghomogeneousandflawlessgreenbodieswithcomplexgreenshapes.　　Gelcastingconsistsofin situpolymerizationthroughwhichamacromolecularnetwor…  相似文献   

基于.NET架构的J2EE技术设计与开发远程教学系统平台     

阿曼古丽·排祖拉 《教育技术导刊》2006,(13)

提出并实现了一个基于.NET架构的J2EE标准,以WebService为基础的web服务器构建多媒体远程教学系统平台,以此教学平台框架开发的多媒体远程教学系统具有更高的跨平台性和互动性。利用基于.NET架构的J2EE标准,提出了远程教学系统平台的系统设计与实现方法。  相似文献   

Comparing Student Performance and Growth in 2- and 4-Year Institutions     

Strauss  Linda C.  Volkwein  J. Fredericks 《Research in higher education》2002,43(2):133-161

This study examines the organizational characteristics of 51 higher education institutions in relationship to student performance and growth. The study first finds that organizational measures of mission, size, wealth, complexity, and selectivity are statistically represented by the 2-year versus 4-year college mission. Findings indicate that 2-year and 4-year campuses indeed do exert significantly different influences on undergraduate GPA and self-reported intellectual growth. Next, the study uses both OLS regression and HLM to examine these influences. High school percentile rank and college classroom experiences are better predictors of Cum GPA at 4-year institutions, while student effort is a better predictor of GPA at 2-year institutions. Whereas the most important predictors of Cum GPA include precollege measures such as high school percentile rank and SAT score, the most influential predictors of student intellectual growth are campus experiences including classroom vitality, peer support, student effort, commitment, and involvement. Controlling for all other variables, students at 2-year institutions receive higher grades, and students at 4-year campuses experience more growth.  相似文献   

CuO气敏元件的制备及气敏性能研究     

侯振雨  谷永庆  张玉泉  王建新 《河南科技学院学报》2006,34(1):69-71

用Cu2O制备CuO气敏元件，对乙醇、汽油、丁烷和氢气等气氛进行气敏试验，并进行机理分析，结果表明，由Cu2O制备的CuO气敏元件，对所测气体的灵敏度优于由CuO制备的气敏元件。  相似文献   

催化动力学光度法测定痕量钒(V)   总被引：1，自引：0，他引：1  

贾欣欣 《北京城市学院学报》2002,(1):59-61

研究了在酸性介质中痕量钒催化 H2 O2氧化抗坏学酸体系的反应和动力学条件 ,建立了催化动力学光度法测定痕量钒的新方法。该方法的检出限为 0 .0 5 ng/ m L ,线性范围为 0～ 0 .5μg/ 2 5 m L ,该方法用于水样及人发中痕量钒的测定 ,结果令人满意  相似文献   

创建高效J2EE Web应用研究     

王迤冉  齐迎春 《周口师范学院学报》2007,24(5):110-112,123

通过对创建J2EE Web技术的研究，提出了对控制器、业务层模型和数据库访问的改进方法.这些方法能优化Web性能，提高访问速度，对创建高效的Web应用具有一定的借鉴作用.  相似文献   

合成草莓酯的新型催化剂     

盛淑玲  曹培斌 《许昌学院学报》2005,24(2):37-40

综述了无机盐、无机酸、杂多酸(盐)、固体超强酸等催化剂催化合成草莓酯的实验情况.结果表明,硫酸铝、CuCl2 ·2H2 O、固体超强酸SO2 -4 -TiO2 /Al2 O3、活性炭固载硅钨酸等催化剂催化合成草莓酯的收率较高,具有一定的工业应用价值.  相似文献