有机-无机纳米复合气敏材料研究进展

对有机-无机纳米复合气敏材料的最新研究进展进行了综述,并着重论述了有机-无机纳米复合薄膜的制备方法、气敏材料的性能、气敏机理探索三个方面.分析了有机-无机纳米复合气敏材料的发展优势,并对其今后的发展方向进行了展望.     

光折变材料研究进展

光折变材料研究是当今非线性光学学科的一个重要领域和研究热点，概述了光折变材料的特性及其应用；比较，综述了无机晶体，聚合物和无机-有机复合等三类光折变材料的性能，研究进展以及面临的主要问题和发展趋向；评述和展望了近年来出现的无机-有机复合光折变材料的研究意义。潜在优势和发展前景。     

有机/无机纳米复合材料的研究进展

近年来纳米科技得到了迅速发展,由无机纳米粒子与聚合物复合制备的有机/无机纳米复合材料成为现代材料科技发展的重要方向.概述了有机/无机纳米复合材料的制备方法和性能特点;介绍了有机/无机纳米复合材料的应用领域,最后对它的发展前景进行了展望.     

聚酰亚胺／无机纳米杂化材料制备方法EI北大核心CSCD

本发明提供了一种聚酰亚胺／无机纳米杂化材料制备方法,首先合成适用于聚酰亚胺的无机纳米粒子改性剂——亚胺环基硅烷;采用溶胶-凝胶法制备无机氧化物纳米粒子,在溶胶一凝胶反应过程中加入改性剂亚胺环基硅烷,得到有机-无机复合体纳米颗粒;将有机-无机复合体纳米颗粒均匀分散于聚酰胺酸溶液中,经过加热处理得到聚酰亚胺／无机纳米杂化材料。本发明的聚酰亚胺／无机纳米杂化材料制备方法解决了纳米粒子分散的难题,在聚酰亚胺／无机纳米杂化材料中纳米粒子分布均匀,不团聚,有利于其各项性能的充分发挥。     

细乳液聚合制备有机-无机复合纳米粒子的研究进展

从细乳液聚合制备有机-无机复合纳米粒子体系的助剂、聚合方法及过程和提高无机纳米粒子包覆率的措施3个方面介绍了采用细乳液聚合法制备有机-无机复合纳米粒子的最新研究进展,并提出其目前存在的问题、今后的研究重点。     

有机/无机纳米复合质子交换膜的研究进展

通过有机/无机复合的方法可以得到聚合物电解质膜燃料电池(PEMFCs)中用的纳米复合质子交换膜,膜的工作温度、保水能力、机械强度、抗渗透性能和薄膜的综合性能都有大幅度的提高.本文评述了研究得较多的几类有机/无机纳米复合质子交换膜的性能特点及最新研究进展,提出了有机/无机复合质子导电薄膜材料的一些设计和制备原则.     

溶胶-凝胶法制备有机-无机杂化光波导材料研究进展

有机-无机杂化材料因同时具有有机功能基团和无机功能基团的结构特点而易于有机光活性物质和无机活性物质的掺杂已被人们广泛关注和大力研究.溶胶-凝胶法是制备有机-无机杂化光波导材料的主要方法.阐述了溶胶-凝胶法制备杂化材料的原理,比较了几种目前研究得较多的有机-无机杂化光波导材料体系,指出了各自的优缺点,介绍了杂化材料制备光波导器件的工艺流程,最后归纳了溶胶-凝胶法制备有机-无机杂化光波导材料过程中存在的问题.     

有机-无机纳米复合材料的制备与界面特性

有机－无机纳米复合材料是一种新型功能材料，本文综述了有机－无机纳米复合材料的界面特性、与界面效应相关的制备，并对有机－无机纳米复合材料的研究前景进行了展望。     

有机-无机纳米复合材料的制备、性能及应用

综述了有机-无机纳米复合材料的最新发展,包括该类材料的制备方法、性能研究和应用前景.纳米复合技术主要有3种:溶胶-凝胶法、嵌入法和纳米微粒填充法.纳米复合材料的光学和磁学等性能可用Maxwell形态理论、层状结构理论和分形结构理论等来研究.这类材料已在力学、热学、电学、磁学、光学、宇航和生物仿生等领域表现出广阔的应用前景.     

无机—有机纳米杂化材料的分子设计与构筑的研究

着重介绍用分子设计制备无机—有机纳米杂化材料的新方法及其结构、性能演变规律和功能化的工作。特别介绍关于纳米晶—聚合物杂化材料、纳米二氧化硅—聚合物纳米复合材料及其有机—无机聚合物表面结构与性能关系规律。如通过对纳米无机材料功能化修饰,使其含有与聚合物共聚的官能团,实现了与聚氨酯、硅橡胶、环氧树脂的分子组装,形成了无机—有机的互穿网络式嵌断共聚物,大大提高了聚氨酯、硅橡胶和环氧树脂的力学性能和热稳定性能。该聚氨酯杂化材料的拉伸强度和伸长率比未改性前均提高了2倍以上。通过原位聚合、聚合物刷、从表面接枝技术制备出高性能材料。探讨用催化链转移聚合等聚合方法实现新颖有机—无机纳米杂化材料的制备及其表面构筑。通过无机材料的表面设计和表面处理控制无机/聚合物复合材料的界面结构和行为,得到了多种性能优良的多元多尺度复合材料。提高纳米杂化复合高分子材料的加工性能,探索其特异的光电等特异性能。     

Photorefractive processing for large adaptive phased arrays

An adaptive null-steering phased-array optical processor that utilizes a photorefractive crystal to time integrate the adaptive weights and null out correlated jammers is described. This is a beam-steering processor in which the temporal waveform of the desired signal is known but the look direction is not. The processor computes the angle(s) of arrival of the desired signal and steers the array to look in that direction while rotating the nulls of the antenna pattern toward any narrow-band jammers that may be present. We have experimentally demonstrated a simplified version of this adaptive phased-array-radar processor that nulls out the narrow-band jammers by using feedback-correlation detection. In this processor it is assumed that we know a priori only that the signal is broadband and the jammers are narrow band. These are examples of a class of optical processors that use the angular selectivity of volume holograms to form the nulls and look directions in an adaptive phased-array-radar pattern and thereby to harness the computational abilities of three-dimensional parallelism in the volume of photorefractive crystals. The development of this processing in volume holographic system has led to a new algorithm for phased-array-radar processing that uses fewer tapped-delay lines than does the classic time-domain beam former. The optical implementation of the new algorithm has the further advantage of utilization of a single photorefractive crystal to implement as many as a million adaptive weights, allowing the radar system to scale to large size with no increase in processing hardware.     

Photorefractive effect in LiNbO3 directional couplers

Experimental results on the photorefractive effect in Ti-indiffused LiNbO3 directional couplers at GaAs and He-Ne wavelengths are presented. The photorefractive effect has been observed as drift in the switching state of this device at GaAs wavelengths (0.81 and 0.85 Am) for intensities (powers) as low as 32 W/cm 2 (3.2 MW). Analysis of this effect indicates refractive-index changes as large as 8 X 10-4 may be occurring. Measurements also suggest the possibility of two time constants in the relaxation of the photorefractive effect in these devices.     

光折变聚合物材料的研究进展

与无机光折变晶体相比,光折变聚合物材料具有非线性光学系数大,响应时间快,成本低廉,制备灵活等优点,成为近代研究的热点。综述了光折变聚合物材料的发展状况,并分析了当前工作所面临的问题及发展前景。     

光折变聚合物材料研究进展

综述了光致折变聚合物材料的分类方法和近年来光折变聚合物材料的发展状况，认为液晶光折变聚合物材料将有巨大的应用前景。     

掺杂KNSBN光折变材料

KNSBN是我国首创的一类光折变晶体,利用掺杂可改善其性能。本文介绍了掺杂KNSBN的光折变特性与有关性质,包括二波耦合增益系数、自泵浦相位共轭反射率、电光系数等,并比较了掺杂的效果。     

Organic Photorefractive Materials and Applications

This review describes recent advances and applications in the field of organic photorefractive materials, an interesting area in the field of organic electronics and promising candidate for various aspects of photonic applications. We describe the current state of knowledge about the processes involved in the formation of photorefractive gratings in organic materials and focus on the chemical and photo‐physical aspects of the material structures employed in low glass‐transition temperature amorphous composites and organic photorefractive glasses. State‐of‐the art materials are highlighted and recent demonstrations of photonic applications relying on the reversible holographic nature of the photorefractive materials are discussed.     

Continuous monitoring of a surface slope by real-time shearing interferometry with a photorefractive crystal

We propose and demonstrate a new technique for measuring the temporal variations of the surface slope of an object. This real-time shearometric arrangement takes advantage of the dynamic properties of holograms in photorefractive crystals. The accuracy of the measurements should make this technique suitable for real-time structural intensity determinations.     

Writing and probing light-induced waveguides thanks to an endlessly single-mode photonic crystal fiber

We demonstrate writing and probing of light-induced waveguides in photorefractive bulk LiNbO3 crystal using an endlessly single-mode photonic crystal fiber. The optical waveguides are written at visible wavelengths by slightly raising the ferroelectric crystal temperature to benefit from the pyroelectric-driven photorefractive effect and the guiding properties are investigated at telecom wavelengths using the same photonic crystal fiber. End butt coupling with this photonic crystal fiber enables writing and probing of optical waveguides due to the self-alignment properties of spatial solitons.     

Measuring the coherence function of continuous-wave lasers by a photorefractive grating method

We demonstrate a simple, adjustment-insensitive technique for measuring the temporal coherence function of cw multimode and monomode semiconductor lasers, using two-beam coupling in photorefractive InP and CdTe crystals. The emission spectra of the diodes are measured independently. The coherence functions are also calculated from these spectra and agree with the photorefractive measurements. Coupling of two partially coherent waves in low-speed photorefractive media is described theoretically. The range of the experimental parameters in which the method of coherence measurement is correct is given.     

Single beam one-way imaging through a thick dynamic turbulent medium

A new method to record an image through a thick dynamic phase distorting medium by using a photorefractive LiNbO3 crystal is demonstrated. The method uses only one beam of light, the object light. By making use of the photorefractive fanning effect, gratings are formed in the LiNbO3 crystal through the interference between the object light and its own fanning light. Because the time scale of the distorting fluctuation is much shorter than the writing time of the LiNbO3 crystal, the fluctuated light does not induce any fanning. Therefore only the static portion of the image is recorded in the crystal, and the intensity distribution of the image can then be reconstructed at any later time.