刚果红交联聚乙烯醇薄膜／K^＋交换玻璃光波导检测氯化氢气体

用环氧氯丙烷为交联剂合成了刚果红(CR)交联聚乙烯醇(PVA)CR-PVA敏感试剂.用匀胶机将其做成薄膜固定在钾离子交换玻璃光波导表面,研制出一种光波导氯化氢气体传感器.CR-PVA薄膜碱式结构的最大吸收波长在600 nm以下,对波长为632.8 nm的激光吸收很弱;薄膜与酸性气体发生反应后强烈吸收波长在632.8 nm附近的导波或消失波;检测输出光强度的变化,即能够测出酸性气体浓度.测试结果表明,本传感器对低浓度HCl气体有快速响应,且对1.6～192 mg/m3范围内有良好的线性响应;SO2、NO2气体的浓度大于18000 mg/m3时才有响应,而对于高、低浓度H2S气体均无响应.     

二甲苯蒸气玻璃光波导传感元件的研制

本文利用浸渍-提拉法,将镍掺杂的过氧聚钨酸(PTA)复合薄膜固定在锡(Sn2+,Sn4+)掺杂的玻璃光波导(Sn doped glass slide OWG)表面,研制出了一种高灵敏的二甲苯蒸气光波导传感元件.采用流动注射法对二甲苯蒸气进行了检测.实验结果表明,在室温下,该传感元件对浓度在1.0×10-6～1.0×10...     

热处理对LiFe1-0.01xY0.005xAg0.005xPO4薄膜光波导传感元件气敏性的影响

以FeSO4.7H2O,H3PO4,LiOH.H2O,AgNO3及Y(NO3)3.6H2O为原料,利用水热法一步合成出了LiFe1-0.01xY0.005xAg0.005xPO4粉体(x=0.5,1.0),并将该材料作为敏感试剂,用旋转-甩涂法做成纳米薄膜固定在锡掺杂玻璃光波导表面,在不同温度下进行热处理。采用紫外-可见分光光度计、测厚仪以及自组装的玻璃光波导气敏测试仪研究了热处理对LiFe1-0.01xY0.005xAg0.005xPO4薄膜光学及气敏特性的影响。研究结果表明:在450℃下进行热处理的薄膜元件具有良好的光学透明及较好的气敏特性。相同浓度的不同挥发性有机气体中,该传感元件对二甲苯气体有很好的选择性响应,其检测响应范围为1×10-7～1×10-3(V/V),响应-恢复时间分别小于5和100 s。     

MB-硬脂酸复合薄膜光波导传感器检测氯化氢气体

利用旋转甩涂法将亚甲基蓝(MB)掺杂的硬脂酸溶液涂成薄膜固定在钾离子(K⁺)交换玻璃光波导表面上, 研制了MB-硬脂酸复合薄膜/K⁺交换玻璃光波导传感器, 并对酸性气体进行了检测. 该复合薄膜与氯化氢(HCl)气体作用时, 薄膜颜色从深蓝色变为浅蓝色, 导致薄膜对倏逝波的吸收降低, 使传感器的输出光强度增强. 结果表明, 在室温下该传感器对低浓度的氯化氢气体仍具有较好的重复性和选择性响应, 可检测到体积分数为1×10^-6%的HCl气体, 响应和恢复时间分别为7和20 s, 相对标准偏差为±6.06%. 该传感器具有灵敏度高、 响应-恢复速度快、 可逆性好、 成本低和容易制备等特点.     

Thin film composite optical waveguides for sensor applications: a review

We review the design and fabrication of thin-film composite optical waveguides (OWG) with high refractive index for sensor applications. A highly sensitive optical sensor device has been developed on the basis of thin-film, composite OWG. The thin-film OWG was deposited onto the surface of a potassium-ion-exchanged (K⁺) glass OWG by sputtering or spin coating (5–9 mm wide, and with tapers at both ends). By allowing an adiabatic transition of the guided light from the secondary OWG to the thin-film OWG, the electric field of the evanescent wave at the thin film was enhanced. The attenuation of the guided light in the thin film layer was small, and the guided light intensity changed sensitively with the refractive index of the cladding layer. Our experimental results demonstrate that thin-film, composite OWG gas sensors or immunosensors are much more sensitive than sensors based on other technologies.     

高耐盐性吸水树脂的紫外光引发合成及其性能

采用紫外光引发聚合法合成了聚乙烯醇与丙烯酸钠高耐盐性吸水树脂.用红外光谱和热重分析法对产物进行了表征,测定了该树脂的溶胀动力学、可逆性能及温度、pH、离子浓度和有机溶剂等因素对树脂吸附率的影响.结果表明:该树脂在蒸馏水中的吸水率为4 100 g/g,在w=0.9%的NaCl水溶液中的吸盐水率为405 g/g;树脂的吸液率与阳离子的价态有关,其吸液率大小顺序为NaCl＞CaCl2＞FeCl3;其溶胀动力学扩散过程中的膨胀指数0.5＜n＜1,属于non-Fickon扩散.     

基于3S的塔里木河中游景观格局变化特征分析

景观格局变化研究,是目前景观生态学的研究热点.本文把生态环境脆弱与人类活动的影响比较强烈的塔里木河中游选为研究靶区,利用遥感的手段获取试验区1973、1992和2000年景观格局的基础数据,在3S技术和景观生态学方法支持下,对塔里木河中游近30年土地利用和景观结构的时空变化特征进行了研究,对该地区的开发利用和生态环境保护提供科学依据.     

Composite optical waveguide composed of a tapered film of bromothymol blue evaporated onto a potassium ion-exchanged waveguide and its application as a guided wave absorption-based ammonia-gas sensor

For what is the first time to our knowledge, we have successfully evaporated a tapered film of bromothymol blue (BTB) onto a potassium ion-exchanged (PIE) waveguide to form a composite optical waveguide (COWG) for trace-ammonia detection. The BTB film has a high refractive index (1.69) and a smooth surface and is transparent to a 633-nm laser beam in air. In the COWG structure, the BTB film serves as a single-mode waveguide, and adiabatic transition of the TE(0) mode was realized between the BTB waveguide and the PIE waveguide with both BTB tapers. In the presence of ammonia, the BTB film changes color from yellow to blue, which causes absorption of the 633-nm guided wave. Our experimental results demonstrate that such a guided wave absorption-based ammonia-gas sensor is much more sensitive than one based on evanescent-wave absorption. A detection limit of part in 10(9) of ammonia has been realized for a BTB film-PIE glass COWG.     

Rational design of molecularly imprinted polymer: the choice of cross-linker

The paper describes a rational approach for the selection of cross-linkers during the development of molecularly imprinted polymers (MIPs). As a model system for this research MIPs specific for the drug zidovudine (AZT) were designed and tested. Three cross-linkers trimethylolpropane trimethacrylate (TRIM), ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB) were studied. The analogue of zidovudine (AZT) ester (AZT-ES) was used as a dummy template. The imprinting factors for all of the polymers in the static adsorption experiments were calculated. The data on the AZT adsorption by control polymers (CP), which were prepared with different cross-linkers without a functional monomer, was also analyzed. DVB was found to be more inert towards zidovudine than EGDMA and TRIM, which was confirmed by both molecular modelling and adsorption experiments. It was demonstrated that DVB-based polymers had a higher imprinting factor (I = 1.85) compared with other tested cross-linked polymers. It was suggested that the selection of the cross-linker should be based on the strength of the interaction with the template: the cross-linker which displays lower binding of the template should be preferential because it generates MIPs with lower non-specific binding and a higher imprinting factor, and therefore specificity. Which cross-linker to use for the preparation of any particular MIP can be determined by analysis of the interactions between the cross-linker and template. This could be done either virtually using computational modelling or by template adsorption using a small library of polymers prepared using different cross-linkers.