Preparation of Neodymium-Doped Yttrium Aluminum Garnet Transparent Ceramics by Homogeneous Precipitation Method

Neodymium-doped yttriumaluminumgarnet(Nd∶YAG)transparent polycrystalline ceramics,laser ce-ramic matrix materials,are gradually becomingsubsti-tutes for single crystals because they are provided withpredominantly chemical stability,highly doped ionconcentration,excellent optical performance and hightemperature stability[1,2].Presently,the conventionallyused methods to produce Nd∶YAG powders are solid-state processes[3],chemical precipitation methods[4,5]andlowtemperature combustiontechniqu…     

低温燃烧法合成Ce1-xNdxO2-x/2（0≤x≤0．6）纳米粉体

采用低温燃烧合成法，在柠檬酸-硝酸盐体系中合成出Ce1-xNdxO2-x/2（0≤x≤0．6）固溶体纳米粉体。X射线衍射（XRD）结果表明，Nd^3＋取代Ce^4＋进入晶格内部，形成具有单相立方萤石结构的固溶体，其晶格常数随Nd^3＋掺杂浓度的增大而线性增加，晶粒尺寸在15-24nm之间。透射电镜（TEM）结果表明，粉体颗粒尺寸在20-40nm之间，分散性较好，具有较高的烧结活性。拉曼光谱（Raman Spectrum）结果表明，F2g宽化峰的出现与掺杂后固溶体中产生的氧空位有关，并且随着掺杂浓度的增加，氧空位数量也再增加。     

复合助烧剂对Gd2O3-UO2芯块微观结构的影响

Gd2O3-UO2可燃毒物燃料是近年来核电站采用较为普遍的可燃毒物之一。本文研究了在Gd2O3-UO2芯块中添加A12O3、TiO2、V2O5各150μg／g的复合助烧剂对芯块微观结构的影响。研究表明添加复合助烧剂后可以降低Gd2O3-UO2芯块的致密化温度．在H2气氛中，1500℃烧结4h后的Gd2O3-UO2芯块的密度可达～97％TD，芯块的闭口孔在1400～1750℃整个温度范围内一直呈下降趋势．烧结温度为1750℃时芯块中气孔数量比1600℃时减少．但单个气孔体积增大．其主要机制可能是小气孔之间发生融合。添加助烧剂后，在1400～1600℃温度之间晶粒生长速度出现不一致．部分晶粒开始迅速生长，晶粒大小分布出现双峰现象；当温度为1750℃时，晶粒大小分布为正态分布．双峰现象消失，平均晶粒尺寸约为25μm。     

UML在开发工业远程监控系统中的应用

采用面向对象分析设计语言(UML)和面向对象语言(MSVC++)相结合,在整个软件生命周期均采用面向对象方法和工具实现工业远程实时监控系统,得到了结构良好、高内聚、低耦合、容易理解、易于扩展、维护的系统。     

永磁同步电动机与磁钢性能的关系

永磁电机性能的好坏，直接与所采用的永磁材料的性能参数有着密切的关系。本文分析了永磁同步电动机与磁钢性能的关系，指出由于磁性能优异的永磁材料的采用，使电机的性能指标得到很大提高和改善，并获得了明显的经济效益。接着阐明了永磁同步电动机设计中，应着重考虑的问题，最后，指出了永磁同步电动机的研究方向。     

重稀土锰基化合物Gd（Mn,Co）Si的结构与磁性

通过金属钴对锰的替代，考察了Ｇｄ（ＭｎＣｏ）Ｓｉ化合物的晶体结构，居里温度ＴＣ和磁化率随替代量变化的规律，初步探讨了重稀土Ｇｄ原子同过渡金属Ｃｏ，Ｍｎ原子之间以及过渡金属原子与过渡金属原子之间的磁相互作用。     

添加钕对Mg2Ni储氢合金的结构和电极性能的影响

利用两步法制备了一系列添加Nd的三元Mg2-xNdxNi合金。XRD分析证实，当x=0．05，0．1时，制得的三元Mg2-xNdxNi合金均为Mg2Ni单相合金；三元Mg18Nd0．2Ni(x=0．2，0．3)合金为三相合金，三相分别为Mg2Ni，NdNi，NdMgNi4。模拟电池测试结果表明，同Mg2Ni合金相比，球磨10h的三元Mg1．8Nd0．2Ni合金和Mg17Nd03Ni合金电极的放电容量提高明显，且Mg17Nd03Ni合金电极的循环性能有明显改善。这极有可能与合金中NdMgNi4相的存在以及球磨形成的微结构有关。     

Structure and Waveguide Properties of Sol-Gel Derived Gd2O3 Films

Pure and rare earth doped gadolinium oxide (Gd2O3) waveguide films were prepared by a simple sol-gel process and dip-coating method. Structure of Gd2O3 films annealed at different temperature was investigated by X-ray diffraction and transmission electron microscopy. Oriented growth of (400) face of Gd2O3 has been observed when the films were deposited on amorphous substrate. The refractive index and thickness of films were determined by m-lines spectroscopy. The laser beam (λ= 632.8 nm) was coupled into the film by a prism coupler and the propagation length is about 3.5 cm. Luminescence properties of europium ions doped films were measured by waveguide fluorescence spectroscopy, which shows disordered environment for Eu^3 at 400℃.     

Effect of Nd3+ substitution on structural and magnetic properties of Mg–Cd ferrites synthesized by microwave sintering technique

Nd~(3+) substituted spinel ferrites with formula Mg_xCd_(1-x)Nd_(0.03)Fe_(1.97)O_4(x = 0.0.2,0.4,0.6.0.8 and 1.0)were prepared by oxalate co-precipitation method using novel microwave sintering technique. AR grade sulphates were used as starting chemicals. The samples were sintered at optimized power of 70 W for10 min in a microwave oven(800 W). The structural analysis of these samples was done by using X-ray diffraction, scanning electron microscope and Fourier transform IR techniques. The XRD analysis of the synthesized ferrite confirms the formation of cubic spinel structure of ferrite. The influence of Nd3+substitution on various structural parameters of Mg-Cd ferrites was reported. IR study indicates the spectra contain two intense absorption bands around 600 and 400 cm~(-1) in addition with four extra bands. The magnetic properties of all ferrites were studied by using a vibration sample magnetometer.The crystallite and grain size dependant magnetic properties are observed. The composition Mg_(0.6)Cd_(0.4)Nd_(0.03)Fe_(1.97)O_4 has better magnetic properties that can be used in recording media. The fast synthesis of spinel ferrites is yielded due to use of the microwave sintering technique.