银掺杂对二氧化钛晶型转变的影响

采用溶胶-凝胶法制备了银掺杂的TiO2粉末,用XRD分析了掺银TiO2胶体经不同温度热处理后的晶型转变。结果表明:与未掺银的TiO2粉末相比,掺银TiO2从锐钛矿相向金红石相转变的起始温度较高,而且锐钛矿-金红石相变的温区范围变窄,晶型转变过程较快。     

掺铜TiO^2光催化剂光催化氧化还原性能的研究

利用浸渍法制备了掺铜二氧化钛光催化剂，分别以乙酸降解和二氧化碳还原反应为探针，研究了催化剂的光催化氧化光催化还原性能．结果表明，铜掺杂能显著提高催化剂的光催化性能；结合光电子能谱、X光衍射分析等物理表征结果，对铜掺杂改性机制进行了讨论．     

Effects of oxidation on I2 doping of trans-polyacetylene as studied via e.s.r. and conductivity measurements

Oxidation of trans-polyacetylene lowers the activation energy for conduction from 16 kcal mol^?1 to 11 kcal mol^?1 for oxidation levels of (C₂H₂O_n)_x, n = 0.144, 0.207 and 0.550. Maximum conductivity levels for 0 < x < 0.144 doped with I₂ were almost identical. At long I₂ doping times all samples exhibited some loss of conductivity. E.s.r. experiments indicate that: (1) linewidth is directly proportional to oxygen content, and (2) iodine doping is not diffusion controlled. All data are consistent with a molecular picture of PAC consisting of highly reactive localized spin states that are selectively oxidized, and less reactive delocalized states that affect conductivity more strongly via doping.     

Energy Transfer and Population Inversion in Heavy Metal Oxide Glasses Doped with Tm3+ and Tb3+

Emission properties and energy transfer of PbO–Bi₂O₃–Ga₂O₃–GeO₂ glasses codoped with Tm³⁺ and Tb³⁺ ions were investigated. The 1.48-μm emission due to the Tm³⁺:³H₄→³F₄ transition can be used to amplify the S-band (1460–1530-nm) signal light. With Tb³⁺ addition, the lifetime and emission intensity of the Tm³⁺:³F₄ level decreased sharply via the Tm³⁺:³F₄→Tb³⁺:⁷F_0,1,2 energy transfer. Population densities of the ³F₄ and ³H₄ levels in Tm³⁺ calculated from rate equations clearly verified that population inversion in Tm³⁺ ions became possible with as little as 0.1 mol% of Tb³⁺ addition.     

Preparation of V doped lanthanum silicate electrolyte ceramics by combustion method and study on conductance mechanism

Vanadium doped La_9.33Si_6−xV_xO_26+0.5x (x = 0.5, 1.0, 1.5) (LSVO) electrolyte powder was prepared by combustion method at 600°C for 5-7 min. The powder was sintered at 1500°C for 3 hours to prepare LSVO ceramics. XPS, IR, XRD, and EIS analysis show that V⁵⁺ doping replaces Si⁴⁺ in [SiO₄] to form [Si(V)O₄] tetrahedron. With the increase in x, the lattice volume increase. When x = 2.0, the LaVO₄ phase was formed, indicating that the limit doping amount of V⁵⁺ replacing Si⁴⁺ is x ≤ 1.5. The conductivity of LSVO increases significantly with the increase in x (x ≤ 1.0), which attributed to the defect reaction caused by V⁵⁺ doping. The addition of the interstitial oxygen Oi* in 6₃ channels and the increase of lattice volume leads to increased conductivity. When x = 1.0, the highest conductivity is 1.46 × 10⁻² S·cm⁻¹ (800°C). The doping enhancement conductivity mechanism is the Interstitial oxygen defect-Lattice volume composite enhancement mechanism.     

Mg2+掺杂的LiFePO4材料的共沉淀合成与表征

提出了一种采用共沉淀法合成镁掺杂的锂离子正极材料LiFePO4的新方法,研究了合成条件,采用XRD,SEM,循环伏安测定,电化学阻抗谱分析,以及充放电测试对合成的材料作了表征分析．结果表明,采用共沉淀合成方法可以获得性能良好的LiFePO4;Mg^2＋掺杂对LiFePO4结构没有产生明显的影响,但掺杂量的大小对LiFePO4的放电性能有较大影响．     

Sr/Zr掺杂以及抛光对BaTiO_3陶瓷结构和介电性能的影响

采用冷压陶瓷技术制备了(Ba0.75Sr0.25)TiO3、Ba(Ti0.8Zr0.2)O3、(Ba0.75Sr0.25)(Ti0.8Zr0.2)O3陶瓷.XRD结果表明,Sr和Zr在BaTiO3的Ba位、Ti位、及Ba/Ti双位并入均具有高固溶性,且为没有超结构特征的单相钙钛矿结构.Sr/Zr的双位并入加快介电峰向低温的移动.Sr掺杂对Ba(Ti0.8Zr0.2)O3介电峰移动率的贡献为-1.5℃/mol%Sr.抛光技术对介电温谱的影响研究表明,尽管水抛光导致(Ba0.75Sr0.25)(Ti0.8Zr0.2)O3陶瓷颜色变暗,但晶体结构不变、介电峰值降低.     

钕掺杂钛酸钡陶瓷材料的制备及电阻-温度依存性的研究

讨论了稀土元素钕(Nd)对钛酸钡陶瓷材料的微观结构和介电性能的影响,以BaCO3、Nd2O3和TiO2为原材料采用固相法贮备了掺杂钕的BaCO3、TiO2纳米粉体,并经高温烧结后得到(Ba1-xNdx)Ti1-x/4O3基片,并对其进行测试,研究了钕掺杂对钛酸钡陶瓷电阻-温度依存性.     

电化学沉积法制备稀土掺杂氧化钇荧光薄膜的发光性能

通过改变氧化钇薄膜中掺杂稀土元素的种类,来控制发光薄膜的荧光发射波长.利用电化学沉积法制备稀土掺杂氧化钇荧光薄膜.电化学沉积法制备的薄膜结晶效果好,掺杂离子分布较均匀,且不需要高温高压或者真空条件,成本很低.所制备的Y2O3:Ln荧光发光薄膜经XRD分析具有立方晶体结构;不同稀土掺杂的氧化钇呈现出不同的表面形貌;掺杂的Ln离子均匀地分布在薄膜中,经测试所有的Y2O3:Ln荧光发光薄膜都显示出较强的发射强度,且发光波长随着掺杂离子的不同而不同:Y2O3:Er3+发绿光,Y2O3:Ce3+发黄绿光,Y2 O3:Sm3+发蓝光,Y2O3:Pr3+发橙光.因此,电化学沉积法可用于制备具有不同发光波长的氧化钇荧光薄膜.     

陶瓷电容器的制备工艺概述

简介了新型陶瓷电容器的优点、功能、类型和发展现状及表面层陶瓷电容器、表面层型陶瓷电容器和晶界型陶瓷电容器的产生机理和区别，和影响陶瓷电容器性能的诸多因素，如显微结构、掺杂元素和包覆改性等；回顾了国内外陶瓷电容器的烧成工艺发展历史，如高温一次烧成、低温一次烧成、独石法和激光辐射法等；展望了陶瓷电容器在21世纪的研究和应用前景。