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81.
利用电子束引发预辐射接枝技术,在聚全氟乙丙烯(FEP)膜上接枝丙烯酸(AA)和对苯乙烯磺酸钠(SSS)两单体,制备出一种含羧酸基团和磺酸基团的阳离子交换膜,接枝率越高,接枝膜的吸碱性能越好。差示量热扫描及X射线衍射测试表明,接枝膜结晶度随接枝率的升高而降低。这是接枝膜中FEP组份的“结晶变形”及接枝链对晶区的“稀释作用”综合影响的结果。 相似文献
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In the present study, the influence of chromium on the microstructure and etching behaviour of the polycrystalline alloy Ni–13Fe–8Al–4Ti (at-%) has been examined. The alloy was recently designed for nanomembrane fabrication, but although it showed the necessary γ/γ′ microstructure with cubic, well aligned γ′ precipitates, it proved to be unsuitable for nanomembrane fabrication as the γ matrix was dissolved during chemical etching. To obtain the passivation of the γ matrix, chromium has been added in further modifications containing 1, 2, 3 and 4 at-% chromium. Moreover, the influence of heat treatment and the different cooling rates of heat treatment in air/vacuum have been investigated. For chemical phase extraction, the application of the chemical etchants MoO3 acid and ‘G’ etchant has been examined, the formability was characterised by Vickers hardness testing. The main purpose of the present study, namely the passivation of the γ matrix, could be achieved by the addition of 4 at-% chromium and etching with ‘G’ etchant. 相似文献
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Cheng Tian Jing Liu Ruofan Ruan Xinlong Tian Xiaoyong Lai Lei Xing Yaqiong Su Wei Huang Yang Cao Jinchun Tu 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(23)
Solar‐driven vaporization is a sustainable solution to water and energy scarcity. However, most of the present evaporators are still suffering from inefficient utilization of converted thermal energy. Herein, a universal sandwich membrane strategy is demonstrated by confining the hierarchical porous carbon cells in two energy barriers to obtain a high‐efficiency evaporator with a rapid water evaporation rate of 1.87 kg m?2 h?1 under 1 sun illumination, which is among the highest performance for carbon‐based and wood‐based evaporators. The significantly enhanced evaporation rate is mainly attributed to the inherently optimized porous evaporation mode derived from the hierarchical hollow structures of pollen carbon cells, and the synergistically regulated water transporting and thermal management performance of the sandwich membrane. Moreover, the constructed sandwich membrane also exhibits excellent self‐regenerating performance in simulated seawater and high salinity water. The developed device can maintain an average evaporation rate of 4.3 L m?2 day?1 in a 25 day consecutive outdoor test. 相似文献
87.
阳离子基团的分布对阴离子交换膜的微观相态和阴离子传导率有显著的影响.为开发全钒液流电池用高性能阴离子交换膜,本文通过向含有二甲胺基团的氟化聚芴醚前驱体接枝含阳离子烷基链的方式,合成了具有相似离子交换容量的一系列侧链多阳离子型氟化聚芴醚.实验结果表明,多阳离子侧链的引入能促进微观相分离的形成并提升阴离子传导率.同时,侧链... 相似文献
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Quanlong Yang Sergey Kruk Yuehong Xu Qingwei Wang Yogesh Kumar Srivastava Kirill Koshelev Ivan Kravchenko Ranjan Singh Jiaguang Han Yuri Kivshar Ilya Shadrivov 《Advanced functional materials》2020,30(4)
All‐dielectric metasurfaces have become a new paradigm for flat optics as they allow flexible engineering of the electromagnetic space of propagating waves. Such metasurfaces are usually composed of individual subwavelength elements embedded into a host medium or placed on a substrate, which often diminishes the quality of the resonances. The substrate imposes limitations on the metasurface functionalities, especially for infrared and terahertz frequencies. Here a novel concept of membrane Huygens' metasurfaces is introduced. The metasurfaces feature an inverted design, and they consist of arrays of holes made in a thin membrane of high‐index dielectric material, with the response governed by the electric and magnetic Mie resonances excited within dielectric domains of the membrane. Highly efficient transmission combined with the 2π phase coverage in the freestanding membranes is demonstrated. Several functional metadevices for wavefront control are designed, including beam deflector, a lens, and an axicon. Such membrane metasurfaces provide novel opportunities for efficient large‐area metadevices, whose advanced functionality is defined by structuring rather than by chemical composition. 相似文献
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