PULSED LASER DEPOSITION AND CHARACTERIZATION OF FERHOELECTHIC Pb(Zr, Ti)O3 THIN FILMS ON SILICON-ON-INSULATOR SUBSTRATES

Ferroelectric Pb(Zr, Ti)O₃ thin films were prepared by pulsed exeimer laser deposition on silicon-on-insulator and Pt-coated silicon-on-insulator substrates, and rapid thermal annealing was per-formed to crystallize the films, Based on the analysis by X-ray diffraction, Rutherford backscattering spectroscopy and measurements of electrical properties, the films were revealed to be polycrystalline perovskite structure with mainly (100) and (110) orientations, and their crystallization was found to be dependent on annealing temperature and annealing time. The films show good ferroelectricity, with P_r=15μC/cm², E_c= 50kV/cm, high resistivity and high dielectric constant.     

金属颗粒薄膜巨磁电阻效应的影响因素

研究金属颗粒薄膜的颗粒尺寸、磁性组分等对巨磁电阻效应的影响.在自由电子模型和自旋相关散射理论的基础上，计算了金属颗粒膜体系的电子平均散射势.在计算过程中将自旋相关项与宏观量相联系，得到了巨磁电阻效应与磁性成分比例、颗粒尺寸的关系.磁电阻效应的模拟曲线表明，增加磁性成分比例和减小磁性颗粒尺寸可增强颗粒膜的巨磁电阻效应. 关键词：     

利用啁啾光纤光栅色散特性实现波长可调谐的主动锁模掺铒光纤环行腔激光器

在环形腔主动锁模光纤激光器中引入啁啾光纤光栅，利用啁啾光纤光栅的大色散特性，通过调节调制频率，实现波长调谐，调谐范围2nm。所得脉冲为重复频率2．5GHz，脉宽约60ps的正啁啾脉冲，。     

基于光纤光栅的可调谐半导体激光器

本文利用光纤光栅(FBG)形成外腔反馈及F-P半导体激光器的多模特性,得到波长稳定、可调谐的半导体激光光源,系统研究了不同反馈比率对激光器光谱特性的影响.通过向FBG施加轴向拉力和压力可实现10nm的波长调谐,得到一系列波长间隔0.94nm的激光输出,边模抑制比达35dB,光谱线宽小于0.2nm.     

6,6‘—二（二苯基氧化膦甲基）—1,1’—氮氧化—2,2‘—联吡啶与…

合成了硝酸铒与四功能团含磷萃取剂６，６’－二（二苯基氧化膦甲基）－１，１’氮氧化－２，２’－联吡啶的配合物。用四圆衍射仪测定了配合物的晶体结构。金属离子周转的配位水分子已全部被取代。     

A Dual-Wavelength Cladding-Pumped Er^3＋/Yb^3＋ Codoped Fibre Laser System with More Than 2 W Output and Tunable Wavelength Spacing

A dual-wavelength laser system with wideband tunable wavelength spacing and more than 2 W output power is proposed and demonstrated. The operation principle of the laser system is based on the saturation gain characteristic of a cladding-pumped Era＋ /yba＋ co-doped fibre amplifier combining with a wideband tunable fibre laser with fiat power spectrum. The tuning range of the wavelength spacing is continuous within a 35 nm spectral range, and the power difference between both lasing wavelengths can be easily adjusted and controlled by a variable optical attenuator. The total output power can approximately keep unchangeable when the wavelength spacing and the power difference between both lasing wavelengths are continuously tuned and changed. The maximum total output power of the laser system is about 2.22 W.     

核科学百年讲座第五讲辐射化学与辐射加工

介绍辐射化学和辐射加工的发展与应用，以及基本原理，侧重介绍辐射加工在高分子辐射交联改性、食品的辐照处理和医疗用品消毒等方面的应用．     

集合与函数中易混淆的几对问题

集合是高中数学的基础，函数是高中数学的核心，同学们在学习中应注意理解有关概念的内涵，深入分析集合与函数的基本性质，把握住问题的本质属性，为学好高中数学奠定坚实的基础．本文就集合与函数中易混淆的几个问题逐对解析。希望学生从中受到启发，弄清楚两者的区别．     

原子核的振动与转动模型(Ⅲ)A～190区超形变带研究

应用推转玻尔-莫特逊哈密顿量导得了超形变带的转动谱公式,应用这一公式研究了在A～190区24个超形变带的跃迁能量和能级自旋,获得了满意的结果.     

顺二羰基2－丁酸甲酯基吡啶铑配合物的合成与性能

顺二羰基２－丁酸甲酯基吡啶铑配合物的合成与性能潘平来，柳忠阳，黄茂开，袁国卿（中国科学院化学研究所，北京１０００８０）含有不同配位基团的共聚物配体与铑形成的配合物，在催化甲醇碳基化制备乙酸和乙酐的反应中具有很高的活性和选择性￣［１１］。本文采用含有Ｎ...