偶氮苯掺杂聚合物光致双折射的一维空间分布

报道了偶氮苯掺杂聚合物光致双折射空间分布的实验研究。发现在光照区域外较大的范嗣内有双折射，证实了生色团分子的取向运动及其引起的周边分子相互运动的存在。对3种偶氮苯染料分散红1(DR1)。分散红13(DRl3)和分散黄7(DY7)掺杂的聚甲基丙烯酸甲酯(PMMA)聚合物进行了定性研究。发现生色团分子的取向运动及其引起的周边分子相互运动与抽运光强度和生色团分子的大小等因素有关。     

偶氮苯聚合物薄膜光致表面调制效应研究

实验观测了偶氮苯聚合物薄膜在Ar^ 激光（488nm)激发下的光表面调制效应。给出了488nm激光激发条件下,含有不同偶氮苯侧基的聚合物的光表面调制效应的数值。分析比较了偶氮苯聚合物表面调制效应的强弱及其产生的原因。给出光表面调制效应与聚合物接枝率的关系。     

掺杂偶氮苯聚合物薄膜光致双折射特性

通过改变激励光光强以及激励光偏振方向与探测光偏振方向的夹角θ,研究一种新的掺杂偶氮苯聚合物薄膜光致双折射的特性。实验结果表明该掺杂偶氮苯聚合物薄膜在低激励光强下具有良好的光信息储存性能,是一种很有潜力的光储存材料。对有关实验结果作出了定性的解释。     

偶氮侧链聚合物液晶薄膜光致双折射及其光存储实验

本文实验研究了偶氮侧链聚合物液晶薄膜（P-CN）的光致双折射和光存储性质。在连续 532nm激光作用下,该液晶薄膜（P-CN）表现出显著的光致双折射（△n～10-2）。基于光致双折射效应,实验中获得了长久的、高对比度的光信息记录。     

偶氮苯聚合物薄膜光致表面调制效应研究（Ⅱ）

实验观测了DP-AN系列偶氮苯聚合物薄膜在Ar^ 激光（488nm）激发下的光致表面调制效应。给出488nm激光激发条件下,含有不同偶氮苯侧基的聚合物的光致表面调制效应的数值。在前文^[1]工作的基础上分析比较了DP-AN系列和BP-AN系列偶氮苯聚合物光致表面调制效应的不同及其产生的原因。给出影响偶氮苯聚合物光致表面调制效应的因素。     

偶氮侧链液晶聚合物薄膜中基于光致双折射效应长久光存储的机理探讨

本文比较了连续矾酸钇锐频激光（输出波长532nm），脉冲Nd:YAG倍频激光（输出波长532nm、脉宽8ns、重复频率10Hz）作用下，偶氮侧链液晶聚合物薄膜的光致双折射效应和光记录特性。根据实验结果和数值模拟情况^[8]，引入温度效应，提出分子团积和主链链段取向效应，给出了基于光致双折射效应长久光信息记录的解释。     

偶氮苯聚合物的光致双折射数学模型的优化

通过计算机模拟对含偶氮苯生色团的无定型共聚物的光致双折射进行研究,分析其光致双折射的写入、弛豫持性,对光致双折射的产生机制提出了一个新的数学模型。通过改变理论模型的参数,用穷举法求出具有不同参数的理论模型与实验数据之间误差的最小值,从而求出最理想数学模型的参数。     

掺偶氮苯聚合物的光致折射率改变特性

采用表面反射方法研究块状掺偶氮苯聚合物的光致折射率改变特性及其与光强的依赖关系；实验中，使用514nm的圆偏振Ar^ 激光作为抽运光，632．8nm的He-Ne激光(s偏振)作为探测光。通过改变探测光入射角，测量样品在固定光强(0．570W／cm^2)的前向抽运光激励下表面反射率的改变量．研究样品的折射率改变特性．发现样品的光致折射率改变约为0．0035；研究了这种效应对抽运光强度的依赖关系．发现光致折射率改变随抽运光强度增大而增大．当抽运光强为0．800W／cm^2时，折射率改变量可达10^-2量级。     

偶氮聚合物光存储研究进展

着重阐明了偶氮聚合物光存储纪录的原理,分析了其双折射特性的微观机制,介绍了该课题近年来实验和理论上的最新进展,对这一充满希望和挑战的多学科交叉研究专题作了展望。     

一种新型含偶氮聚合物的偏振全息研究

对一种含偶氮侧链聚合物介质的光致双折射性质进行了研究。结果表明 ,该聚合物具有大的光致双折射系数 (Δn=7.8× 10 - 3) ,并利用该样品实现了高衍射效率的偏振全息图像的记录 ,实验所得偏振全息图衍射效率为 η=19.3 %。     

Strain-induced birefringence in a highly birefringent optical fibre

A simple theory to explain the strain-induced birefringence in a highly birefringent fibre with an arbitrary cross-sectional geometry is presented. The effects caused by the distributions of Young's modulus and Poisson's ratio in the fibre are highlighted. The phase difference due to the strain-induced birefringence is found to be approximately 20 times larger than that due to the change of fibre length for typical silica-based glass fibres.<>     

光纤中压力感生双折射灵敏度的分析

为了得到高双折射光纤受到的外界应力与相应产生的双折射之间的关系,提高测量系统的稳定性,通过对其应力元和光纤涂覆的弹性性能、泊松比、材料以及厚度加以分析研究.分析和数值仿真结果表明,具有理想弹性性能、小体积模量的足够厚涂覆层可以提高压力感生双折射.     

Pressure-induced birefringence in a coated highly birefringentoptical fiber

An attempt is made to explain the pressure-induced birefringence in a birefringent fiber based on a consideration of the effect due to the difference between the elastic properties of the stress-applying regions and the cladding of the fiber. The elastic properties and the thickness of a single fiber coating are also incorporated into the analysis. Numerical results for some typical coating materials are presented and compared with existing experimental data. The implications of the results with regard to sensor applications are also discussed. A polarimetric sensor using a suitably coated highly birefringent fiber should be useful for the detection of static and low-frequency acoustic pressures     

Considerations of pressure induced birefringence in highly birefringent fibres

Whilst attempting to design a polarimetric highly birefringent (HB) pressure sensor, approximate formulae were developed for the pressure variation of the birefringence of HB fibres with stress regions made from different elastic parameter materials. In the process of producing this result, a complete reworking of an existing basic analysis was found to be necessary.     

含偶氮苯弯曲液晶的光化学性质研究

研究了紫外光照和温度对偶氮弯曲液晶极化电流的影响。在365 nm紫外光照下,这种偶氮化合物的极化强度随紫外光照时间增加而变化直至为零;当温度从150^oC 升高到 175^oC时,弯曲液晶的极化电流随温度线性降低,用Landau-de Gennes理论解释了这一现象。其极化情况随紫外光照和温度而变化的实验规律表明：在紫外光照下偶氮弯曲液晶发生了光致异构化、光裂解和热裂解作用。     

高双折射光子晶体光纤及其传感研究进展

高双折射光子晶体光纤(PCF)具有很多独特的性质,成为近些年光通信领域的研究热点.在综述国内外大量文献的基础上,分析了高双折射PCF的保偏原理,介绍了高双折射PCF的各种设计方案,总结了高双折射PCF在传感方面的应用,并对其发展前景进行了展望.     

Hygrothermal effects upon stress relaxation in a polyimide film

Polyimide films are being used extensively in first and second level microelec-tronic packages. Despite their many advantages, the tendency of polyimide films to absorb moisture can pose serious reliability problems such as corrosion, internal shorts, delamination, loss in dimensional stability, and a reduction in mechanical performance. This paper presents the results of an investigation of the effects of moisture upon stress relaxation in Kapton^#x00AE; polyimide films. Three relaxation frames were designed and built so that they could be placed side by side within an environmental chamber which controlled both temperature and relative humidity. Stress relaxation experiments were then conducted in triplicate at various combinations of temperature and relative humidity and the relaxation modulus was determined as a function of time, temperature, and moisture concentration. While the relaxation modulus was found to decrease with increasing temperature and moisture concentration, this plasticizing effect could not be described by the simplifying assumption of time-temperature-moisture superposition except for those results obtained at or below 50% relative humidity. Application of the time-temperature superposition principle to the results obtained at relative humidities higher than 50% produced several distinct master curves at constant moisture concentration. These curves had fundamentally different shapes which could not be superimposed by rigid horizontal shifting.     

Design of a highly stable electromagnet power supply

A method for designing a highly stable electromagnet power supply combining the 12-pulse phase-controlled rectifier (PCR), passive filter, and transformed active filter is investigated. The PCR system is analyzed, and passive filter parameters are designed from this analysis. A phase-locked voltage control circuit with a fast dynamic characteristic is analyzed, and an optimal constant proportional-integral and measurable variable feedback plus feedforward (PIMF) current controller is designed using a time-weighted quadratic performance index. It is shown via experimental results that the proposed design method gives good performance     

紫外光照下偶氮香蕉型液晶的光吸收特性研究

借助紫外可见光谱仪观测和电子结构计算,研究了紫外光照对偶氮香蕉型液晶电子结构和光吸收特性的影响。吸收光谱显示：这种液晶的两个光学吸收峰分别位于360nm和275 nm。电子结构计算表明：这两个光学吸收主要来自于液晶中含偶氮官能团的电子跃迁。结果表明：36５nm光子可将液晶中的氮氮双键打断,从而导致其在360nm处的吸收迅速降低,同时使275 nm处的吸收相应增加。     

Topography engineering of ferroelectric crystalline copolymer film

Effects of surface roughness as well as crystallinity onto functionalities of crystalline copolymer films were studied using a dipping method to inject the crystalline grains into voids among crystalline nano-rods. Differently from a widely-used fabrication method such as spin-coating of solution, we achieved a smooth surface and high crystallinity in ferroelectric P(VDF-TrFE) films, simultaneously. Varying dipping temperature and time, remnant polarization and relative dielectric constant values increased by 20% and 75% with a decrease of surface roughness from 20 nm to 7 nm in root mean square value, respectively. The ferroelectric stabilities of P(VDF-TrFE) film capacitors were found to be strongly dependent on the crystallinity.