LaF_3及LaF_3(掺杂)固体电解质的特性及其应用

对LaF3及LaF3(掺杂 )作为固体电解质的导电能力和特性进行了分析。讨论了掺杂对LaF3导电性的影响。介绍了LaF3及LaF3(掺杂 )单晶固体电解质在室温水溶液中氟离子选择电极、多晶固体电解质在高温熔体中镧传感器、以及各类气体传感器中的应用     

掺镧八钼酸铵制备工艺研究

本文主要对掺镧八钼酸铵制备工艺进行探索研究。在八钼酸铵制备过程中,通过在不同阶段加入硝酸镧,制备掺镧八钼酸铵。确定了掺镧八钼酸铵的制备过程中硝酸镧加入方式和加入时间;通过对掺镧过程溶液pH值的考察试验,确定掺镧八钼酸铵制备工艺为液-液掺杂;重复和均匀性试验完善和证明了液-液掺镧八钼酸铵制备工艺。     

Influence of Lanthanum on Tribological Properties and Microstructure of Laser Clad B ＋ Fe ＋ Si Composite Coatings

The effects of rare earth ferrosilicon on the microstructure and anti-wear properties of laser-clad Fe-based alloy coating were investigated. The composition of Fe, B4C and rare earth ferrosillcon powders with different contents of lanthanum were clad onto a 45 # carbon steel substrate. Microstructural features, chemical compositions, phase structure,hardness, friction and wear properties by scanning electron microscopy (SEM), X-ray photoelectron microscopy (XPS),hardness tester, block-on-ring friction and wear tester of the clad coating were determined. Experimental results show that the friction coefficient of the clad coating doped with rare earth ferrosilicon is reduced while the wear resistance of clad coating doped with rare earth ferrosilicon is enhanced. When the content of lanthanum increases to 1.92%, the clad coating shows the best anti-wear ability, and as the content of lanthanum exceeds 1.92%, the wear weight loss increases quickly. The rare earth ferrosilicon to be doped in the clad coatings helps to disperse the boride phase (Fe2B, FeB, B4C)particles and refine the grain of boride phase. The enhancement of clad coating‘s wear resistance is due to the existence of dispersed boride phases.     

掺杂对氢化燃烧合成镁基储氢合金性能的影响

借助XRD、SEM和自制放氢量的测试装置研究了掺杂对氢化燃烧合成镁镍储氢合金性能的影响。结果表明：三种掺杂中以掺富铈镧系金属产生的镁镍氢化物最多,掺铜产生镁镍氢化物的晶格畸变最为明显。晶胞分析显示Mg_2NiH_4的晶胞参数都有一定的变化。300℃、0．1 MPa下放氢速率的测量显示,掺杂降低了放氢温度,放氢速率一般为6～10 min。掺铜放氢量为2．68％,掺钛放氢量为2．35％,掺富铈镧系金属放氢量为3．10％,掺钛、掺富铈镧系金属活化可适当提高吸放氢量。     

Existing Forms of Lanthanum in Purity Steels

Adding lanthanum to carbon-manganese purity steel, the existing forms of lanthanum were investigated. The results show that enrichment on grain boundary and solid solution in cementite are two kinds of important existing forms of lanthanum relating to micro-alloyed action. As a result of enrichment of lanthanum, the concentration of lanthanum aggregated on somewhere of grain boundary reaches as high as tens of times of its average content although the average content is very low. In addition, lanthanum atoms can replace partial Fe atoms that constitute cementite to form alloyed cementite, the solid solution amount of lanthanum in alloyed cementite increases as the increase of its average content in purity steel.     

锂对LaCaCrO3稳定性及热膨胀的影响

采用固相法制备了掺杂Ca和Li的LaCrO3试样, 并研究了其稳定性及热膨胀. 结果表明,掺Li量为0.05 mol时会对LaCrO3低温相变处的热膨胀性能产生影响, 变化幅度大于80%;掺Li量超过0.10mol时热膨胀系数及热膨胀率变大, 但波动幅度减小, 小于25%. 无论是否添加Ca元素, 掺Li量大于0.15mol都会使材料发生粉化失效现象.     

Preparation and Characterization on Nano-Sized Barium Titanate Powder Doped with Lanthanum by Sol-Gel Process

The nano-sized BaTiO3:La3 powders were prepared by sol-gel process using butyl phthalate, barium acetate and lanthanum oxide as raw material, and these samples were tested by means of TG-DTA, XRD and SEM. The results indicate that with the annealing temperature and the doped concentration rising, the powders' particle sizes will increase and decrease respectively. When annealing temperature is 900 ℃ and doped concentration is 7%, the phase is cubic without other phases, and the particle size of power is 43.34 nm.     

Properties of Magnetic Nanoparticles about Doped Rare Earth and Its Composites

The magnetic liquid was prepared with ferric salt by inorganic gel technology. The effect of the doped rare earth elements on the properties of magnetic particles was analyzed. The magnetic liquid was composed with clay mineral into magnetic mineral composites. The crystal structure and micro-morphology of the nanoparticles were studied by XRD and TEM. The results show that the crystal structure of the magnetic particles doped 0.5 % of lanthanum is more complete, and the magnetic response capability is higher with doping agent. At the same time, the possibility of the clay mineral magnetic composites as the carrier of target drug was probed.     

Aging Effect on Lanthanum Doped Ferroelectric Lead Titanate Ceramics

Ferroelectric devices are widely applied in many fields, such as energy conversion and communication. The aging effect in ferroelectric materials plays a central role in the reliability of the related equipments. But it is very difficult to understand the origin of aging effect in ferroelectrics because these materials possess different defects and exhibit various aging behavior. The reverse transition temperature in lead titanate doped with lanthanum increases during aging at ferroelectric phase was reported. It is well known that lattice defects, such as vacancies and solute atoms, are ubiquitous in crystalline solids. These point defects affect physical properties in ferroelectrics significantly. The abnormal increase of the reverse transition temperature was discussed in terms of diffusion of point defects during aging. Dielectric performance in the material after aging was measured and discussed as well.     

Preparation and Structure Characterization of Rare Earth Doped Alumina-Siloxane Gel and Its Modification on ER Effect

A series of samples of alumina-siloxane gel wrapped by poly (methyl methacrylate) and doped with rare earths such as lanthanum, praseodymium, yttrium, gadolinium and europium were prepared. The structure features were characterized by micrograph, X-ray fluorescence spectrum, X-ray diffraction spectrum, Fourier transform infrared spectrum and differential thermal analysis.Tests indicate that rare earths modify the electrorheological effects of the stable suspensions composed of samples stirred with silicon oil.     

Influence of lanthanum doping on performance of LiFePO4 cathode materials for lithium-ion batteries

Using solid-state synthesis method,a series of samples of lanthanum doped Li1-xLaxFePO4(x=0.0025,0.005,0.0075,0.01) were prepared.Each cathode structural and electrochemical properties were investigated using X-ray diffractometry(XRD),scanning electron microscopy(SEM),electrochemical impedance spectroscopy(EIS) and charge/discharge cycling.Nanopowders material with single-phase could be obtained.The reversible capacity could be drastically improved by the introduction of La.The optimum cells with Li0.99La0....     

Synthesis and Characteristic Study on Complexes of Europium（Ⅲ） and Maleic Acid Doped with Non-Fluorescent Ions

Complex of europium （Ⅲ） with maleic acid, and binuclear complexes of europium（Ⅲ）with maleic acid doped with non-fluorescent ions gadolinium, lanthanum and yttrium, were synthesized. The compositions and structures of complexes were characterized with elemental analysis, single crystal X-ray diffraction, IR and DSC-TG. Fluorescent properties were studied with fluorescence spectrum. The results indicated that the strongest fluorescent complexes were obtained when the ratio of europium and non-fluorescent ion was 8：2. The order of Eu^3＋ fluorescence strengthened by three doped rare earths was Gd^3＋ 〉La^3＋ 〉Y^3＋     

碳酸氢钠沉淀镧及碳酸镧的结晶过程研究

以pH值原位测定法为基础,结合沉淀体积变化、沉淀粒度及外观形貌分析结果,对NaHCO3上学同淀镧的性能及碳酸镧的结晶过程进行了研究。结果表明：碳酸镧结晶活性区域位于低配比区0．541－2．828之间,而在高配比区其结晶是惰性的。同时还考察了搅拌对结晶过程的影响,讨论了NaHCO3沉淀镧时的沉淀反应和结晶化机理。并给出了相关的化学反应方程式。     

Thermally stable lanthanum-doped mesoporous alumina as a stable support for palladium in catalytic oxidation of C3H8

High thermally stable mesoporous alumina doped with lanthanum was synthesized using inorganic nitrates as precursors and employing pluronic P123 （P123, （EO20PO70EO20, EO=ethylene oxide, PO=propylene oxide）） as a structure-directing agent. After calcination at 400 oC, the resultant lanthanum doped alumina exhibited aγ-Al2O3 phase, which was the same as pure alumina. After the thermal treatment up to 1200 oC, La-doped Al2O3 generated only one phase ofθ-Al2O3 rather than two mixed phase ofθ-Al2O3 andα-Al2O3 and the surface area could still maintain 101 m2/g with a keeping pore volume of 0.66 cm3/g. The excellent thermal sta-bility was explained by the titration of strong Lewis acid sites ofγ-Al2O3 with the assistance of highly dispersed lanthanum species covering on alumina. Furthermore, the lanthanum modified mesoporous alumina was preliminarily employed as a stable support for Pd in the catalytic oxidation of C3H8.     

Infrared Laser Pumped Green and Blue Laser Emissions from a Single Solid State Material Doped by Rare Earth ions

The possible ways and progress of infrared or red laser pumped green and blue laser emissions from a single solid state material doped by rare earth ions are outlined. The green and blue lasers realized from infrared laser pumped rare earth doped nonlinear laser crystals by means of self-frequency-conversion and from infrared laser pumped rare earth-doped bulk, fiber and microsphere materials by means of frequency upconversion are introduced in detail. Other kinds of devices and methods are also compared. The typical nonlinear laser crystals such as YA13(BO3)4, GdA13(BO3)4, YCa4O(BO3)3,GdCa4O(BO3)3, and the typical upconversion fluoride fibers are compared and analyzed. The major problems remaining to be solved and the developing trends in the area are also discussed.     

碳酸镧沉淀的自发结晶性能

根据碳酸镧沉淀与结晶过程中溶液pH值和沉淀粒度的测定结果,对碳酸镧沉淀的自发结晶性能进行了研究,结果表明碳酸镧自发结晶的活性区域位于碳酸氢铵与镧离子的沉淀反应摩尔比1∶1～2.8∶1之间。而在高配比区域碳酸镧的结晶是惰性的。考察了加料方式、加料速度、加料比等对碳酸镧结晶的影响,并对碳酸镧的结晶化机理进行了讨论,提出了相关的沉淀和结晶过程的化学反应方程式。     

结晶紫褪色光度法测定痕量镧

基于在氯化十六烷基吡啶存在下,稀酸介质中,La(Ⅲ)催化KIO4氧化结晶紫的褪色反应,建立了一个测定痕量La(Ⅲ)的催化动力学光度分析法.讨论了酸度、试剂用量、温度、干扰离子等因素的影响,优化了反应条件.该方法的线性范围为0.02 μg/mL～8.0 μg/mL La(Ⅲ),检出限为0.012 μg/mL La(Ⅲ).将本方法用于催化剂中痕量镧的测定,回收率为96.0％～106.0％.     

稀土掺杂对钛酸锶钡光催化的影响

以溶胶-凝胶法制备钛酸锶钡，研究了制备条件及稀土掺杂对光催化影响。用大红染料模拟废水中难降解的有机物，以大红染料脱色率的变化来表征催化剂BST的光催化性能。结果表明，离子掺杂对大红染料的降解效果比钛酸锶钡的降解效果有所提高。掺入镧离子时降解率可达85％，提高60％；掺入钇离子时降解率可达65％，提高40％；两种离子掺杂时降解率可达70％，提高45％。     

Modification Research on Polypropylene with Acrylic-Silicon Oil Lanthanum

It is hard that inducting rare earth into common resin by bond combination. General plastic polypropylene (PP) containing rare earth was prepared by the bond combination of PP and acrylic-silicon oil lanthanum, which was obtained by reaction of acrylic acid ethylene silicon oil. The principle and method of the graft copolymerization of PP and acrylicsilicon oil lanthanum were discussed. The graft copolymer was characterized by scanning electron microscope (SEM). The mechanical property of graft copolymer was measured by electronic tensile testing machine and impact testing machine. The experimental results showed that crosslinking reaction between PP and acrylic-silicon oil lanthanum happened, acrylic-silicon oil lanthanum did not harm PP's performances. PP's tensile strength almost kept the same and impact strength obviously increased.     

Influence of Lanthanum on Fluorescence Properties of Ag-BaO Thin Films

Ag-BaO thin films doped with lanthanum were prepared by vacuum deposition. Compared with the normal Ag-BaO thin film, there is almost no change with the shape and the peak site of the fluorescence spectrum; however, fluores-cence emission strength of the whole observation band(325 -600 nm)increases about 40%, and the increase of short wavelength range is more remarkable than that of long wavelength range, which we named “blue-stronger“ phenomenon. Analytic results show that, with the forming of intermetallic compounds between silver and lanthanum, the 4f-state energy levels lie just below the Fermi level within 5 eV. It is the energy exchange between the 4f energy levels and the conduction band that causes the increase effect of fluorescence emission, and it is the optical absorption cross section of 4f electron, which increases with the increase of energy of incidence photon, that gives rise to the “blue-stronger“ phenomenon.