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碳纳米管/聚乙烯复合材料薄膜紫外线透过性能的研究 总被引:4,自引:0,他引:4
阳光中的紫外线是引起高分子材料老化的最主要因素,高分子材料被紫外线照射后发生一系列的光化学反应,导致材料变色、变脆、透明度下降和力学性能降低,缩短了其使用寿命,长期以来,围绕紫外光对高分子材料老化作用的问题,科学工作者进行了广泛的观测和研究。结果表明,在高 相似文献
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C. Herrero Latorre J. Barciela GarcíaAuthor VitaeS. García MartínAuthor Vitae R.M. Peña CrecenteAuthor Vitae 《Analytica chimica acta》2013
Selenium is an essential element for the normal cellular function of living organisms. However, selenium is toxic at concentrations of only three to five times higher than the essential concentration. The inorganic forms (mainly selenite and selenate) present in environmental water generally exhibit higher toxicity (up to 40 times) than organic forms. Therefore, the determination of low levels of different inorganic selenium species in water is an analytical challenge. Solid-phase extraction has been used as a separation and/or preconcentration technique prior to the determination of selenium species due to the need for accurate measurements for Se species in water at extremely low levels. The present paper provides a critical review of the published methods for inorganic selenium speciation in water samples using solid phase extraction as a preconcentration procedure. On the basis of more than 75 references, the different speciation strategies used for this task have been highlighted and classified. The solid-phase extraction sorbents and the performance and analytical characteristics of the developed methods for Se speciation are also discussed. 相似文献
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Cu–Fe–CNTs and Ni–Fe–CNTs coatings were deposited on gray cast iron by a hydrothermal approach. It was demonstrated that, the flaky graphite of gray cast iron was exfoliated to graphene nanosheets under hydrothermal reactions, and graphene nanosheets were scrolled to CNTs. After high temperature treatments, the volume losses of Cu–Fe–CNTs and Ni–Fe–CNTs coatings were 52.6 % and 40.0 % of gray cast iron substrate at 60 min wear tests, respectively, obviously increasing the wear properties of gray cast iron. During hydrothermal reactions, water jets and shock waves were produced by bubble collapse. Induced by the water jets and shock waves, exfoliation of flaky graphite was performed, producing exfoliated graphene nanosheets. Attacked by the radially distributed water jets and shock waves, graphene nanosheets were curved, shaped to semicircle morphology and eventually scrolled to tubular CNTs. 相似文献
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The effects of thinner on rubber specimens with carbon nanotubes (CNTs) and graphitic nanofillers (GR) was studied for robotics applications. Rubber specimens were prepared by dispersing GR, CNTs and thinner in room temperature vulcanized (RTV) silicone rubber through solution mixing. Microscopic studies have confirmed occurrence of swelling in polymer chains due to migration of thinner. It results an increase in topological depth from 40 nm (no thinner) to 120 nm (40 phr of thinner). An elastic modulus of ~4.4 MPa (without thinner) was higher than 2.8 MPa (10 phr of thinner). At 100% strain, the lower dissipation losses of 110% (without thinner) and 70% (40 phr of thinner) were obtained. The resistance increases from 4.6 kΩ (without thinner) to 5.7 kΩ (10 phr of thinner). At 0.4‐mm‐thick elastomer slab, an actuation displacement of 0.81 mm (without thinner) was obtained which increased to 1.1 mm (60 phr of thinner). Thus, the thinner can be useful for easier processing, controlled stiffness, minimizing dissipation losses, increasing the actuation displacement and decreasing the cost of the device. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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Wei Chu Maofei Ran Xu Zhang Ning Wang Yufei Wang Heping Xie Xiusong Zhao 《Journal of Energy Chemistry》2013,22(1):136-144
Through our newly-developed “chemical vapor deposition integrated process (CVD-IP)” using carbon dioxide (CO2) as the raw material and only carbon source introduced, CO2 could be catalytically activated and converted to a new solid-form product, i.e., carbon nanotubes (CO2-derived) at a quite high yield (the single-pass carbon yield in the solid-form carbon-product produced from CO2 catalytic capture and conversion was more than 30% at a single-pass carbon-base). For comparison, when only pure carbon dioxide was introduced using the conventional CVD method without integrated process, no solid-form carbon-material product could be formed. In the addition of saturated steam at room temperature in the feed for CVD, there were much more end-opening carbon nano-tubes produced, at a slightly higher carbon yield. These inspiring works opened a remarkable and alternative new approach for carbon dioxide catalytic capture to solid-form product, comparing with that of CO2 sequestration (CCS) or CO2 mineralization (solidification), etc. As a result, there was much less body volume and almost no greenhouse effect for this solid-form carbon-material than those of primitive carbon dioxide. 相似文献
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Erping Cao Zhimin Chen Hao Wu Peng Yu Ying Wang Fei Xiao Shuo Chen Shichao Du Ying Xie Yiqun Wu Zhiyu Ren 《Angewandte Chemie (International ed. in English)》2020,59(10):4154-4160
Even though transition‐metal phosphides (TMPs) have been developed as promising alternatives to Pt catalyst for the hydrogen evolution reaction (HER), further improvement of their performance requires fine regulation of the TMP sites related to their specific electronic structure. Herein, for the first time, boron (B)‐modulated electrocatalytic characteristics in CoP anchored on the carbon nanotubes (B‐CoP/CNT) with impressive HER activities over a wide pH range are reported. The HER performance surpasses commercial Pt/C in both neutral and alkaline media at large current density (>100 mA cm?2). A combined experimental and theoretical study identified that the B dopant could reform the local electronic configuration and atomic arrangement of bonded Co and adjacent P atoms, enhance the electrons’ delocalization capacity of Co atoms for high electrical conductivity, and optimize the free energy of H adsorption and H2 desorption on the active sites for better HER kinetics. 相似文献
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In this paper, a broad overview on the applications of different carbon-based nanomaterials, including nanodiamonds, fullerenes, carbon nanotubes, graphene, carbon nanofibers, carbon nanocones-disks and nanohorns, as well as their functionalized forms, in sample preparation is provided. Particular attention has been paid to graphene because many papers regarding its application in this research field are becoming available. The distinctive properties, derivatization methods and application techniques of these materials were summarized and compared. According to their research status and perspective, these nanomaterials were classified in four groups (I: graphene and carbon nanotubes; II: carbon nanofibers; III: fullerenes; and IV: nanodiamonds, carbon nanocones/disks and carbon nanohorns) and characteristics and future trends of every group were discussed. 相似文献
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碳纳米管负载纳米TiO2复合材料的制备及其性能 总被引:3,自引:0,他引:3
采用溶胶-凝胶法, 以钛酸丁酯为原料, 将纳米TiO2负载在碳纳米管(CNTs)表面, 制备了CNT-TiO2光催化复合材料. 通过X射线衍射(XRD)、透射电子显微镜(TEM)等手段研究了复合颗粒的形态结构及包覆情况, 通过UV-Vis漫反射谱分析比较了纯TiO2和CNT-TiO2的吸光性能, 并研究了不同温度热处理的CNT-TiO2光催化剂在紫外光照射下对甲基橙光催化降解的性能. 结果表明, 纳米TiO2颗粒以锐钛矿相存在, 紧密地包附在碳纳米管的管壁上, CNT-TiO2在紫外-可见光波长范围内均有较好的吸光性能, 450 ℃热处理后的复合光催化剂CNT-TiO2比纯TiO2对甲基橙光降解有更高的光催化活性. 相似文献
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