Effects of Nb2O5 on thermal stability and optical properties of Er3+-doped tellurite glasses

Er³⁺-doped tellurite glasses with molar compositions of xNb₂O₅-(14.7-x)Na₂O--10ZnO--5K₂O--10GeO₂-- 60TeO₂--0.3Er₂O₃ (x=0, 3, 5, 7 and 9) have been investigated for developing 1.5~μm fibre and planar amplifiers. The effects of Nb₂O₅ on the thermal stability and optical properties of Er³⁺-doped tellurite glasses have been discussed. It is noted that the incorporation of Nb₂O₅ (x=5) increases the thermal stability of tellurite glasses significantly. Er³⁺-doped niobium tellurite glasses exhibit a large stimulated emission cross-section (7.2\times 10^-21- 10.7×10^-21~cm² and the gain bandwidth, FWHM×\sigma_e^{\rm peak} (274\times 10^-28 - 480×10^-28~cm³), which are significantly higher than that of silicate and phosphate glasses. In addition, the intensity of upconversion luminescence of the Er³⁺-doped niobium tellurite glasses decreases rapidly with increasing Nb₂O₅ content. As a result, Er³⁺-doped niobium tellurite glasses might be a potential candidate for developing laser or optical amplifier devices.     

基于LiCo0.8M0.2O2 (M=Ni,Zr)薄膜的全固态薄膜锂电池

用射频磁控溅射结合传统退火的方法制备LiCo0.8M0.2O2 (M=Ni,Zr)阴极薄膜．X射线衍射、拉曼光谱、扫描电子显微镜等手段表征了不同掺杂的LiCo0.8M0.2O2薄膜．结果显示,700℃退火的LiCo0.8M0．2O2薄膜具有类似α-NaFeO2的层状结构．通过对不同掺杂锂钴氧阴极的全固态薄膜锂电池Li／LiPON／LiCo0.8M0.2O2的电化学性能研究表明,电化学活性元素Ni的掺杂使全固态电池具有更大的放电容量(56μAh／cm2μm),而非电化学活性元素Zr的掺杂使全固态电池具有更好的循环稳定性．     

Optical spectroscopy of Yb/Er codoped NaY(WO4)2 crystal

Erbium and ytterbium codoped double tungstates NaY(WO₄)₂ crystals were prepared by using Czochralski (CZ) pulling method. The absorption spectra in the region 290-2000 nm have been recorded at room temperature. The Judd-Ofelt theory was applied to the measured values of absorption line strengths to evaluate the spontaneous emission probabilities and stimulated emission cross sections of Er³⁺ ions in NaY(WO₄)₂ crystals. Intensive green and red lights were measured when the sample were pumped by a 974 nm laser diode (LD), especially, the intensities of green upconversion luminescence are very strong. The mechanism of energy transfer from Yb³⁺ to Er³⁺ ions was analyzed. Energy transfer and nonradiative relaxation played an important role in the upconversion process. Photoexcited luminescence experiments are also fulfilled to help analyzing the transit processes of the energy levels.     

两种蓝色有机电致发光材料

重点研究以两种蓝色OEL材料蒽类衍生物JBEM和联苯乙烯衍生物DPVBi分别作基质，以perylene作掺杂剂的器件的电致发光性能，特别研究了它稳定性，在这度和效率方面，两种器件并没有很大差别，然而在稳定性方面却有很大差别，蒽类衍生物JBEM的器件在100cd/m^2初始亮度下，半亮度寿命可达1035h，而DPVBi的器件在同样条件下，半亮度寿命为255h。通过分析两种器件的能级图，认为稳定性的差别可能源于两种蓝光材料本身的热稳定性不同，JBEM优于DPVBi，是一种很有前途的蓝色发光材料。     

固化疏浚泥作为填方材料的试验研究

港口、航道的建设和维护工程产生了大量的疏浚泥，如何处理这些疏浚泥已是国内外十分关注的问题．从资源的再生利用出发，提出利用固化材料固化疏浚泥作为填方材料的设想，并通过强度试验、溶出试验等一系列试验证实，固化疏浚泥作为填方材料在技术经济指标上完全可行．     

磁性纳米颗粒膜的微磁学模拟

用微磁学方法对磁性纳米颗粒膜的磁特性进行了模拟，采用的模型是由122个磁性纳米颗粒组成的面心立方(fcc)结构体系.结果表明：在该体系中，偶极相互作用对体系的静态磁结构的影响显著，而交换相互作用的影响表现不明显.在此基础上，本文还采用有效媒质理论计算分析了磁性合金颗粒不同体积比时颗粒膜的磁谱和表征电磁参量发生显著变化的逾渗现象和逾渗阈值.并完成了对高磁损耗磁性纳米颗粒膜的材料设计. 关键词： 微磁学 纳米颗粒膜 逾渗阈值 磁导率 材料设计     

磁学研究与三环公司发展

简要回顾了20世纪20年代以来我国现代磁学研究的历史。20世纪80年代初期正值我国改革开放浪潮之时，科技人员纷纷走上科技成果产业化道路。建立于1985年的中国科学院三环公司就是一个成功的代表，同时好也是我国现代磁学研究结出的一颗硕果。     

Multi-cracks problem for piezoelectric materials strip subjected to dynamic loading

This paper analyses and models the dynamic interaction among permeable multi-cracks in a piezoelectric strip under anti-plane shear waves by the Schmidt method. The Fourier transform is applied and then two pairs of triple integral equations can be solved using the Schmidt method. The results show that the stress and the electric displacement intensity factors of cracks depend on not only the crack length and the piezoelectric coefficient, but also the thickness of the piezoelectric strip, the distance between multi-cracks and the frequency of incident wave.     

Elasticity in nanocrystalline Nd2Fe14B+αFe magnetic composites

The dynamic Young modulus (E) of magnetic Nd₂Fe₁₄B+αFe nanocomposites is investigated with mechanical spectroscopy techniques (vibrating reed configuration, f≈1.5 kHz <10⁻⁶). Reduced values of E are obtained (88–152 GPa) as compared with that predicted by the rule of mixtures for the composite (164 GPa). Three contributions to this reduction are briefly discussed: a large volume fraction of the specimen with grain boundary like structure; internal pores, resulting from the high cooling rate during processing (10⁶ K/min) and magneto-mechanical effects. Even when porosity is identified as the principal cause of modulus reduction, magnetic effects are also detected.