Pressure-Induced Shifts of R1 and R2 Lines of YAG:Cr3+

By means of improved ligand-field theory, the "pure electronic" pressure-induced shifts (PS's) and the PS's due to electron-phonon interaction (EPI) of R1 line and R2 line of YAG:Cr3 have been calculated, respectively.The calculated results are in very good agreement with the experimental data. It is demonstrated that the admixture of |t22(3T1)e4T2> and |t322E> bases in the wavefunction of R1 level of YAG:Cr3 and its change with pressure play a key role for the PS of R1 line. The behaviors of the "pure electronic" PS of R1 line and the PS of R1 line due to EPI are different. It is the combined effect of them that gives rise to the total PS of R1 line, which has satisfactorily explained the experimental results. The systematic analyses and comparisons between the feature of R1-line PS of YAG:Cr3 and the ones of three laser crystals (GSGG:Cr3 , GGG:Cr3 and ruby) have been made, and the origin of the difference between them has been revealed.     

Modulation of Spin Distribution and Spin Transport by a Magnetic Field in a Quasi-One-Dimensional System with Spin--Orbit Coupling

The distributions of spin and currents modulated by magnetic field in a transverse parabolic confined two-dimensional electronic system with a Rashba spin--orbit coupling have been studied numerically. It is shown that the spin accumulation and the spin related current are generated by magnetic field if the spin--orbit coupling is presented. The distributions of charge and spin currents are antisymmetrical along the cross-section of confined system. A transversely applied electric field does not influence the characteristic behaviour of charge- and spin-dependent properties.     

四方相氧化锆纳米粉的低温合成与表征

氧化锆材料是近年来备受关注的陶瓷材料之一.它在许多不同的领域,诸如陶瓷颜料、工程陶瓷、宝石业、压电元件、离子交换器以及固体电解质方面等有着广泛的用途[1].其最常用的性质是其晶相转变时会有效改善陶瓷的脆性,因此在室温下保持其四方相是其中的关键.为此许多研究都侧重在其中加入各种添加剂,利用水热法、包裹法、形成共溶体等方法来阻止其晶格的转化[2-4].但研究也发现:在固定组成陶瓷基体中,ZrO2的相变温度随粉体颗粒直径的减小而降低,当颗粒足够小时能够提高材料强度的四方ZrO2可以保存到室温甚至室温以下.因此,减小ZrO2粉体粒度对于提高材料强度是非常有利的.本实验采用一种新的低温固相反应的方法制备氧化锆超细粉,从而使这种重要的陶瓷原料的制备有了新的思路.     

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The high speed CCD visible-light camera system has been installed to detect the dynamic characteristics of ELMs filaments on EAST tokamak. In order to convert the CCD video imaging coordinates into real space coordinates, the CCD system has calibrated using Tsai’s two-stage calibration technique. A raised spike in the grayscale profile, drawn by selecting the grayscale value of the image in the vertical direction of the ELMs filament in the CCD image, represents an ELMs filament structure whose positional coordinates are determined by the apex of the spike. The Sobel edge detection operator was used to examine the edge profile of the filament to obtain the width of the filament. By analyzing the characteristics of the filament width of the ELMs, it is found that the width of ELMs filaments continuously decreases outward from the outermost magnetic surface. This indicates that the filaments continue to dissipate energy and particles as they propagate outward. The width of filaments of Type-I ELMs is greater than that of Type-III ELMs.     

Mode equation and its solution for dielectric waveguide with parabolic cross-section

The mode equation for the dielectric waveguide with parabolic cross-section is derived using both the effective index method and WKB theory, and the expression of the mode propagation constant or effective index is solved directly from this mode equation, so that the mode-propagation properties of this kind of waveguide can be analysed conveniently with comparative accuracy.     

激光谐振腔内光学元件的热光效应

本文分析了多模激光束加热内腔元件所引起的温度场分布及热聚焦效应。计算得到的LiNbO₃寻常光和非常光的输入功率-输出功率曲线与Konvisar等人的实验结果符合,修正了他们计算的非常光曲线。在实验上,也观测了LiNbO₃的内腔热光滞后现象,并测量了内腔热光聚焦效应。 关键词：     

热容模式下激光介质的动态光学畸变

 开展了热容模式下激光介质动态光学畸变研究，初步分析了温度梯度、光弹效应及介质端面变形对整个波前畸变带来的影响，并将光学畸变转化为谐振腔损耗，数值模拟了热容激光器输出功率随时间的变化规律，模拟结果表明：当激光器工作温度低于400 K时，由粒子数玻耳兹曼分布引起的功率下降可以忽略，动态热效应是实验中热容激光器输出功率随时间快速下降的原因。     

亚甲基蓝褪色光度法测定肝素

用紫外-可见光谱法研究肝素(Hep)对亚甲基蓝(MB)的褪色反应,在pH3.0的BrittonRobinson缓冲溶液中,肝素与亚甲基蓝形成离子缔合物时,染料发生明显的褪色,体系吸光度的降低与肝素钠浓度成正比.建立了一种简单、灵敏、选择性高的肝素测定方法.本法在0-4.0μg/mL范围内呈现良好的线性关系(r=0.9978),回收率范围为98.8%-101.9%.用于肝素钠注射液的分析,结果令人满意.     

甲醇在不同形态ZrO2上吸附行为的FTIR研究

用FTIR技术考察了甲醇在不同形态氧化锆上的吸附和活化转化行为.甲醇吸附在无定型和四方氧化锆上生成线式和桥式甲氧基物种,而在单斜氧化锆上还出现锥桥式甲氧基物种.在单斜和无定性氧化锆上的桥式羟基活泼而四方氧化锆上的线式羟基活泼.氧化锆表面吸附的甲氧基物种在晶格氧的作用下进一步转化,在单斜和无定性氧化锆上生成甲酸盐,并且可以进一步氧化为碳酸盐物种;而在四方氧化锆表面,甲氧基物种可以直接氧化为碳酸盐物种,这表明四方氧化锆的晶格氧比其他两种氧化锆上的更为活泼.     

铕取代的锆硼钨多金属氧酸盐的制备和发光特性

制备了高发射效率的稀土多金属氧酸盐BPOM:Eu及ZrPOM:Eu荧光体,并对其结构及发光性质进行了研究。结果表明样品具有Keggin结构,Eu在两类样品中均有肉眼可见的在红光区的强发射。但在BPOM:Eu中以⁵D₀→⁷F₁磁偶极跃迁发射为主,在ZrPOM:Eu中以⁵D₀→⁷F₂电偶极跃迁发射为主。铕在ZrPOM:Eu中的对称性低于在BPOM:Eu中的对称性。这种差异也使铕离子的激发光谱具有不同的特征。铕在两种多金属氧酸盐中均有浓度猝灭,在BPOM:Eu中浓度为2.0%时发射强度最大;在ZrPOM:Eu中浓度为2.4%时发射强度最大。在ZrPOM:Eu中有较弱的配体到中心铕离子的能量传递,而在BPOM:Eu中却未观测到能量传递现象。