一种新的双偶氮染料掺杂聚合物薄膜的光致双折射及偏振全息的研究

作为一种有可能作为永久信息存储的材料,合成出一种新的双偶氮材料(BA1)。当样品被波长为532nm的光激发时,几乎大部分BA1分子从反-反态转化到顺-顺态,产生了光致双折射。因此,研究了BA1分子掺杂的PMMA薄膜的光致双折射和透过信号与入射光强度的关系。实验结果表明:透过信号强度随着泵浦光的增强而增强。通过偏振态互相平行(SS)和垂直(SP)的两束偏振光用来研究偏振全息存储,结果表明SP光栅形成的衍射信号要比SS光栅的衍射信号强很多。     

pH/温度双重敏感性微凝胶的合成与应用

智能微凝胶是一类具有独特物理、化学性质的聚合物网络和溶剂组成的体系, 在众多的领域具有潜在的应用.本文介绍了近年来pH和温度双重敏感性微凝胶的研究概况、制备方法及其在药物控制释放、分离纯化和光子晶体方面的应用.     

Faraday镜预转角对FMOCT输出光偏振态的影响

通过计算机仿真,运用琼斯矩阵理论分析了Faraday镜预转角对法拉第镜式光学电流互感器输出光偏振态的影响.实验测量了Faraday镜实际预转角的大小,测量了外磁场的改变对Faraday镜预转角的影响.外磁场的存在和变化使Faraday镜预转角偏离初始值,并使系统输出光由理想状态下的线偏振光退化成椭圆偏振光,并引起法拉第镜式光学电流互感器工作灵敏度和稳定性的下降.提出了用电磁屏蔽解决外界磁场影响的方法.     

光纤拉曼放大器中增益的偏振相关特性研究

提出了一种改进的、可用于计算偏振相关拉曼增益的光纤拉曼放大器的非线性耦合波方程。建立了单模双折射光纤拉曼增益的数学模型,分析了线偏振抽运光以与光纤快轴成45°激励的单模双折射光纤拉曼放大器模型与实际具有随机双折射的光纤拉曼放大器的拉曼增益偏振相关特性的等价性。基于上述模型,提出了一个可定量表征单模光纤偏振模色散统计特性的拉曼增益偏振相关因子,用以替代常规的光纤拉曼放大器非线性耦合波方程中的偏振相关因子。计算结果与已报道文献的实验数据非常吻合。同时对抽运增益在同向和反向抽运方式下截然不同的增益偏振相关特性给出了合理的解释。     

Oriented noncrystalline structure in PET fibers prepared with threadline modification process

The development of an oriented noncrystalline phase in a semicrystalline polymer filament has been studied via X-ray scattering. These unique PET fibers contain a relatively high noncrystalline content and also have high tenacity, high modulus, and low breaking elongation. Fiber properties were found to be very responsive to the oriented amorphous phase content. This phase was utilized for interpreting noncrystalline orientation in PET fibers produced by a new extrusion technique. Here, the oriented noncrystalline regions in a series of PET fibers varies from 6% to 63%, depending strongly on the production conditions. In particular, samples produced with a newly developed threadline modification process possess a high content of oriented noncrystalline polymer. Measurements such as dynamic and static mechanical properties have been performed on various samples, and these properties are related to the oriented noncrystalline phase. The results provide direct evidence for the existence of highly oriented noncrystalline material in these unique PET fibers spun with a threadline modification process. © 1996 John Wiley & Sons, Inc.     

Magnesium hydroperoxyacetate (MHPA) and magnesium dihydroperoxide (MDHP): New antibacterial agents for fibrous substrates

Water-dispersable products have been prepared from the reaction of magnesium acetate tetrahydrate with hydrogen peroxide at mole ratios of 1 : 2 to 1 : 40 to produce compositions with active oxygen or peroxide contents of 1–30%. The products are believed to be stoichiometric mixtures of HOO Mg OAc and HOO Mg OOH that vary in composition with the molar ratios used. These new compounds are hydrolytically stable at ambient temperatures for extended periods (at least 60 days) and thermally stable below 300°C. Pad-cure processes are described for applying the above reaction products as a dispersion in water or aqueous hydrogen peroxide or as a foam in aqueous hydrogen peroxide to impart antibacterial activity to celulosics, synthetic fibers and fiber blends. The textiles are treated with dispersions or foam containing 10–17% of the reaction products derived from mole ratios of 1 : 2 to 1 : 40 magnesium acetate tetrahydrate: hydrogen peroxide. On subsequent heating for 2–4 min at 120–150°C, washing and drying, the modified textiles contain durably bound active oxygen or peroxide (0.1–1.7%) that has activity against representative gram-positive and gramnegative bacteria for up to 50 launderings.     

紫外熔石英元件高精度低缺陷控形控性制造技术研究进展

传统的紫外熔石英元件加工方法本身会引入各类制造缺陷,需要后期加工来消除前期加工带来的缺陷,限制了熔石英元件的加工质量和加工效率。针对这些问题,课题组提出了采用磁流变、离子束、保形光顺和流体动压抛光等可控柔体加工技术提升熔石英元件的加工效果,并开展了相关研究。主要介绍了课题组在关键技术上取得的重要进展,包括亚纳米精度表面控形制造技术、纳米精度本征表面控性生成方法、熔石英元件高精度低缺陷组合工艺与设备等一系列关键技术。通过探讨关键技术及其发展现状,为未来紫外熔石英元件高精度低缺陷制造技术的发展提供参考。     

TracePro在“光的偏振实验”中的应用

为提高光的偏振实验教学效果和教学质量,在教学中引入专业的光学设计软件--TracePro,利用该软件仿真了光的双折射过程和现象,以及偏振片的原理;建立光的偏振实验系统实体模型,完成光的偏振态判断实验;仿真光通过波片后的偏振态转换现象;验证马吕斯定律,并仿真了多层介质膜对光的分离和旋光现象.结果表明该方法可以提高教学效率,激发学生探索科学的主观能动性,仿真结论与理论推导和实际实验结果一致.     

微乳液中球形及棒状SrTiO3纳米粒子的控制合成

以氢氧化锶和钛酸四丁酯为原料, 在水溶液/Triton X-100/环己烷/正己醇反相微乳液体系中制备了直径约为20～80 nm的钛酸锶球形纳米粒子和长约300～1200 nm、直径约为30～150 nm的钛酸锶纳米棒. 用XRD, ICP, TEM, SAED和SEM对样品的结构、成分和形貌进行了表征; 用DLS分析了样品的粒度分布. 结果显示, 水与表面活性剂的物质的量比(ω₀)、反应物浓度、陈化时间等因素都能影响钛酸锶纳米粒子的形貌和尺寸. 所得钛酸锶的锶钛物质的量比约为1.0, 粒度分布较窄, 为立方相单晶结构.     

Mesoporous materials for drug delivery

Research on mesoporous materials for biomedical purposes has experienced an outstanding increase during recent years. Since 2001, when MCM-41 was first proposed as drug-delivery system, silica-based materials, such as SBA-15 or MCM-48, and some metal-organic frameworks have been discussed as drug carriers and controlled-release systems. Mesoporous materials are intended for both systemic-delivery systems and implantable local-delivery devices. The latter application provides very promising possibilities in the field of bone-tissue repair because of the excellent behavior of these materials as bioceramics. This Minireview deals with the advances in this field by the control of the textural parameters, surface functionalization, and the synthesis of sophisticated stimuli-response systems.