可变色的ZnSe:Er3+ MIS发光二极管

本文首次利用高场和低场激发下的有效发光中心,设计和制备了随外加电压极性改变而变色的ZoSe:Er3+ MIS发光二极管。这种发光二极管在正向电压激发下得到蓝色发光,而在反向电压激发下得到绿色发光。     

纳米银胶的光化学制备及其特性研究

采用紫外光化学法制备了黄色银胶,并研究了硝酸银和柠檬酸三钠的浓度对制备的银胶吸收光谱的影响,发现随着硝酸银浓度的增加银胶的吸收峰先兰移然后红移;当柠檬酸三钠的浓度增加时,硝酸银吸收峰的位置几乎不变,而吸收峰强度增大.最后通过透射电镜成像研究其尺寸,发现其尺寸分布在5~20 nm之间.     

93W合金有关力学参量的综合选评

 对93W合金材料进行了超声测量实验，并结合原有的超声测量结果进行了分析比较，提出了可以直接用冲击波速度关系式的三个系数c₀ 、λ和λ′来对钨合金的有关力学参量，如G₀、K₀、G₀′、K₀′等进行综合选评的方法。得到了一组对93W合金较为合理的力学参量推荐值。     

利用多层膜生长技术制备纳米印章模板

在纳米印章技术中，为克服电子束刻蚀制备50nm以下线条的技术难点，利用等离子增强化学 气相沉积技术制备了a-Si/SiN_x多层膜，再利用选择性湿法腐蚀或干法腐蚀在横 截面上制备出浮雕型一维纳米级模板. 多层膜子层之间界面清晰陡峭，可以在纳米量级对子 层厚度进行控制，得到了侧壁在纳米尺度上平滑的模板. 通过控制多层膜子层的生长时间， 制备出线条宽度和槽状宽度均为20nm的等间距模板，品质优于电子束刻蚀技术制备的模板. 关键词： 纳米印章模板 多层膜生长技术     

扇形域上高阶Schwarz边值问题

本文主要讨论一类角度为θ=π/α,α≥1/2的扇形域上高阶多解析方程的Schwarz边值问题.通过构造适当的高阶-Schwarz算子和Pompeiu算子,我们给出了详细的解表达式.本文把边值问题进一步推广到高阶情形,丰富了扇形域上边值问题的发展.     

金纳米颗粒的有序制备及其光学特性

采用纳米球蚀刻技术在石英衬底上制备了不同高度的金纳米颗粒阵列.通过扫描电子显微镜对其表面形貌进行了观测,表明金纳米颗粒为有序分布的三棱柱结构.通过红外—紫外吸收光谱仪在190—900nm波长范围内对其光吸收特性进行了测量, 并成功观测到了金纳米颗粒表面等离子体振荡效应引起的光吸收峰,结果表明随着金纳米颗粒高度的增加,其吸收峰的位置向短波方向移动(蓝移).同时对金纳米颗粒的光吸收特性进行了基于离散偶极子近似的理论计算,并与实验结果进行了比较. 关键词： 纳米球蚀刻技术 金纳米颗粒 离散偶极子近似     

On the non-symmetric planar aligned NLC cell

The planar aligned nematic liquid crystal cell with different anchoring for the two substrates (i.e. a non-symmetric NLC cell) is investigated by an analytical method. We deduce the basic equations and the boundary conditions of the tilt angle θ of the LC director. Expressions for threshold and saturation magnetic field are obtained, and numerical results of these two quantities with variation in anchoring parameters of the two substrates are given. A symmetry breaking parameter Δ is introduced and the relations between Δ and applied field, as well as the two sets of anchoring parameters are discussed in detail. A feasible experimental plan for measurement of anchoring strengths of a series of different substrates is proposed.     

Palladium‐catalyzed selective decarboxylative coupling reaction versus direct C―H arylation for arylation of heteroaromatics

Conditions for selective palladium‐catalyzed decarboxylative 2‐arylation of 3‐substituted thiophene and furan derivatives bearing an ester at C2 position have been established. By using 2 mol% phosphine‐free Pd(OAc)₂ as the catalyst and a mixture of KOH and K₂CO₃ as the bases, in dimethylacetamide, moderate to good yields of the desired 2‐arylated products were obtained. A range of functional groups such as nitrile, nitro, formyl or acetyl on the aryl bromides was tolerated. This method allows us to employ in some cases more convenient reactants in terms of cost or physical properties (boiling point) for arylations. Copyright © 2013 John Wiley & Sons, Ltd.     

On-line writing identical and weak fiber Bragg grating arrays

We investigate the on-line writing identical fiber Bragg grating (FBG) arrays using the phase mask technique. Given the limitation of laser power, the energy density uniformity and the horizontal width of the writing spot cannot be further optimized. The results show that the FBG arrays obtained in the optimal process (drawing speed of 12 ± 0.15 m/min and average tension of 38.2 g) have a central wavelength bandwidth of less than 0.1 nm and an average reflectivity of 0.26%. Thus, the phase mask method is a promising alternative for on-line writing identical FBG arrays.On-line writing identical and weak fiber Bragg grating arrays.     

光致变色多阶游程光存储研究

多阶游程存储是一种不改变光学系统而显著提高光存储容量和数据传输率的新方法.介绍了光致变色多阶游程存储原理和实验系统.提出了基于光致变色原理的多阶游程存储数学模型，该模型反映了记录符反射率与曝光功率、曝光时间之间的非线性关系，并在此基础上确定了光致变色多阶游程存储的写策略.基于650nm光致变色材料进行了4阶游程存储的动态实验.结果表明，实验中采用的650nm光致变色材料可用于多阶游程存储，采用的写策略能够有效地使记录信道线性化，利于采用适合线性系统的信号处理方法. 关键词： 多阶游程 光致变色 光存储 写策略