共查询到19条相似文献,搜索用时 562 毫秒
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在酸氧化后的多壁碳纳米管上化学还原镀钯,用水将镀钯后的碳管清洗至中性并配制成悬浊液,将悬浊液旋涂在真空溅射的叉指金电极表面,干燥后作为气敏膜,把气敏膜暴露于一定浓度的苯气体中,检测传感器的电流变化,并计算其灵敏度。镀钯后的多壁碳管在室温下对苯响应和回复迅速,电导变化与苯气体的浓度呈良好的线性关系,其线性回归方程y=0.0041x 0.1288,r=0.9546。Pd颗粒对苯分子和碳管壁结构缺陷间的电子转移的促进作用可能是多壁碳管镀钯后产生良好气敏响应的原因。 相似文献
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气敏传感器已在生物、化学、航空、军事等领域获得了广泛的应用。鉴于WO3基气敏传感器是检测H2S、NOx、O3和NH3等气体最有前景的新型氧化物气敏传感器之一,本文以不同的敏感气体为分类依据系统阐述了近年来WO3基气敏传感器的研究进展,详细探讨了制备方法及贵金属掺杂对上述各种气体气敏性能的影响,并指出了目前WO3基气敏传感器在研究过程中存在的问题。 相似文献
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ZIF-8是一种Zn基金属有机骨架材料, 可以吸附丙酮气体从而作为电容式丙酮传感器的气敏材料, 然而ZIF-8的传统使用形式为粉末态, 这导致其不能成为具备柔性的整体, 从而限制了传感器的柔性. 结合包埋种子和二次生长法将ZIF-8与纳米纤维结合成纤维型柔性材料, 并将其作为气敏层制备了柔性电容式丙酮气体传感器. 该传感器在9种常见挥发性有机化合物中表现出良好的选择性, 对250~2000 cm3/m3的丙酮气体具有灵敏的响应、良好的循环响应及长期稳定性. 值得注意的是该柔性传感器不仅在室温下进行传感, 而且在弯折180°的状态下对丙酮气体的响应值与不弯折(0°)状态下几乎一致, 在200次以内的180°弯折-恢复后同样表现出了传感性能的稳定, 表明了其在柔性传感器方面的潜力. 相似文献
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室温气敏材料能耗低、稳定性好、安全性高,并且有助于简化传感器的器件结构,具有很好的实际应用前景。开发具有优异室温传感性能的气敏材料成为近年来传感领域的研究热点。金属氧化物半导体材料来源广泛、环境友好、结构调控灵活,在室温气体传感性能方面取得一定的进展。本文介绍了金属氧化物气敏材料的发展历程及气体传感机理,详述了各种具有室温气敏性能的金属氧化物纳米结构,重点讨论构建金属氧化物室温传感性能的有效策略和传感机制,并对室温传感材料的未来发展进行了展望。 相似文献
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优势致腐菌是引起猪肉变质的重要原因之一,为了探索猪肉优势致腐菌绿色、快速的检测方法,本研究使用天然色素作为气体可视化传感器阵列的气敏材料,区分猪肉中的优势致腐菌。首先从植物中提取17种天然色素作为气敏材料,并将其固定在基底材料上,干燥后制成气体可视化传感器阵列。将3种优势致腐菌(梭状芽孢杆菌、热死环丝菌、假单胞菌)分别接种至3组猪肉样本中,在室温(20℃)条件下分别培养8、16和24 h,然后将传感器阵列与猪肉样本产生的挥发性物质接触并发生反应,用扫描仪获取传感器阵列与每个样本反应前后的图像信息,将传感器反应前后的颜色差值作为样本的特征值组成一个数据矩阵,并制成差值图像。最后采用主成分分析对培养8,16和24 h后的3种优势致腐菌进行检测,识别率分别为90%,90%和100%。结果表明,天然色素可以作为气体传感器的气敏材料,检测猪肉的优势致腐菌,且检测过程不会产生化学毒害。 相似文献
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采用水热法制备了一系列具有不同碳量子点(GQDs)含量的MoO3?GQDs纳米复合材料,利用X射线衍射、扫描电子显微镜、透射电子显微镜、FTIR等对MoO3?GQDs复合材料进行了表征,研究了其气敏性能。结果表明,复合材料中GQDs的含量对MoO3?GQDs复合材料的气敏响应和选择性有显著影响。MoO3?GQDs纳米复合材料(S?6,GQDs悬浮液的含量为6 mL)传感器在230℃时对三甲胺(TMA)表现出高的气敏响应和好的气敏选择性;该传感器对1000μL·L^-1 TMA的响应为74.08;对1000μL·L^-1 TMA的响应时间和恢复时间分别为73和34 s;S?6复合材料气敏传感器在230℃时可以检测到1μL·L^-1的TMA。 相似文献
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巴基管嵌锂电极性能的研究 总被引:12,自引:0,他引:12
用化学气相沉积法制备的巴基管作为锂离子电池的负极活性物质可以达到700mAh/g的容量,远超过了石墨嵌锂化合物理论容量。CVD巴基管电极经20次充放电循环后,放电容量保持率为65.3%,尽管CVD巴基管电极初次充放电效率低,但经表面镀铜修饰后,初次充放电效率可提高到55.9%。 相似文献
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V. Efimova A. Derzsi A. Zlotorowicz V. Hoffmann Z. Donkó J. Eckert 《Spectrochimica Acta Part B: Atomic Spectroscopy》2010
The energy transfer to the discharge gas due to various collision processes in the plasma and the heating of the sample are widely known effects in glow discharge (GD) spectroscopy. Despite of the considerable thermal effects and their serious influence on the performance of GD devices, measurements of the discharge gas and sample temperatures are not common at all. The gas temperature depends on the power absorption of the discharge as well as on the temperature of boundaries (sample and anode). In this work the influence of different anode materials in a Grimm-type source on the voltage–current characteristics, crater shapes and GD spectra is investigated. Anodes made of titanium and copper alloys, graphite, and steel with thermal conductivities covering a wide range of values are used. For a fixed voltage and pressure a decrease of the measured current is observed for bad thermal conductive anodes. Cooling of the sample results in an increase of the measured current. Both observations can be explained by changes of the discharge gas temperature. The temperature of the sample is measured from the back side and compared for different anodes. Further, it is found that the choice of the anode material (i) has no significant influence on the crater shape, (ii) results in slightly different sputtering rates and (iii) strong differences of the GD spectra. 相似文献
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Hyo J. Kim Young A. Woo Jong S. Kang Susanna S. Anderson Edward H. Piepmeier 《Mikrochimica acta》2000,134(1-2):1-7
The use of the change in the oscillation frequency of the current of a new atmospheric helium glow discharge for sensitive
signal detection for gas chromatography is studied. The effluent of a capillary column is directed into the glow discharge
cell perpendicular to the axis of the glow discharge that existed between a platinum anode and cathode. A stable discharge
is obtained when several hundred volts are applied between the 0.2-mm gap between the anode and cathode. The effects of the
electrode gap, discharge voltage and gas flow rate on the baseline frequency and discharge current were investigated. The
chromatogram shows that the discharge current and discharge gap have a strong influence on the detector response. The discharge
current shows positive peaks; however, frequency peaks are positive or negative depending on the discharge conditions. The
response of the detector is in the femto-mole and pico-mole range for nonane and decane.
Received August 5, 1997. Revision September 2, 1999 相似文献
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交流放电法合成多种形态的碳纳米管 总被引:3,自引:1,他引:2
碳纳米管的发现[1]引起了科学界的广泛重视,人们对于这种新型材料在纳米导线、高强纤维、超导等方面的应用寄予厚望.目前,合成碳纳米管的方法主要是采用不等径石墨棒直流放电,在阴极上得到含有碳纳米管的沉积物[2].对于碳纳米管的应用,有关的理论研究[3]及... 相似文献
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Huifang An Li Jiang Feng Li Ping Wu Xiaoshu Zhu Shaohua Wei Yiming Zhou 《物理化学学报》2020,36(7):1905034-0
通过氧化石墨烯(GO)和壳聚糖(Cs)之间的氢键以及静电作用形成GO水凝胶,从而将纳米硅颗粒和碳纳米管(CNT)原位包封于其中,再经冷冻干燥及随后的热处理制得三维硅/碳纳米管/石墨烯(Si-CNT@G)纳米复合材料。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)、热重分析(TGA)等技术对制得样品的物相、结构和微观形貌等进行了表征。结果表明,所得复合材料在CNT纵横交织的石墨烯网络中,均匀地分布着纳米硅颗粒。当作为锂离子电池的负极材料时,在两种碳介质的协同作用下,有效缓冲硅材料在充放电过程中脱/嵌锂引起的体积变化,缩短了锂离子和电子传输的距离,Si-CNT@G复合材料表现出较好的循环稳定性以及倍率性能。在500 m A·g~(-1)的充放电电流密度下,经过200圈循环后,其放电比容量仍高达673.7 m Ah·g~(-1),容量保持率高达97%;即使将充放电电流密度升至2000 m A·g~(-1)时,该复合材料仍保持有566.9 m Ah·g~(-1)的高可逆放电比容量。独特的制备方法和优越的储锂性能,使得Si-CNT@G纳米复合材料成为理想的高性能锂离子电池负极材料的候选. 相似文献
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McNicholas TP Zhao K Yang C Hernandez SC Mulchandani A Myung NV Deshusses MA 《The journal of physical chemistry. C, Nanomaterials and interfaces》2011,115(28):13927-13931
Low-cost, low power consumption gas sensors that can detect or quantify various gas analytes are of increasing interest for various applications ranging from mobile health, to environmental exposure assessment and homeland security. In particular miniature gas sensors based on nanomaterials that can be manufactured in the form of sensor arrays present great potential for the development of portable monitoring devices. In this study, we demonstrate that a chemiresistive nanosensor comprised of single walled carbon nanotubes decorated with gold nanoparticles has impressive sensitivity to elemental mercury (Hg) gas concentrations, with a lower detection limit as low as 2 ppb(v). Furthermore, this nanosensor was found to regenerate, though slowly, without any additional recovery steps. Finally, the mercury vapor sensing mechanism allowed for direct investigations into the origin of Surface Enhanced Raman Scattering (SERS) in carbon nanotubes decorated with Au nanoparticles. 相似文献
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Izadi-Najafabadi A Futaba DN Iijima S Hata K 《Journal of the American Chemical Society》2010,132(51):18017-18019
Direct measurement of ion diffusion in aligned, densified single-walled carbon nanotube electrodes showed that the diffusion coefficient for transport of ions (KSCN in acetonitrile) parallel to the alignment direction of the nanotubes was close to the theoretical limit of perfectly straight pores, achieving a value 20 times larger than that of activated carbon electrodes (1 × 10(-5) vs 5 × 10(-7) cm(2)/s). In contrast, the diffusion coefficient for ion transport perpendicular to the alignment direction was an order of magnitude smaller (8 × 10(-7) cm(2)/s). As an example of the ramifications of this anisotropic diffusion phenomenon, the difference in performance of the aligned carbon nanotubes as electrochemical-capacitor electrodes was evaluated. At low discharge rates, the performances of the two orientations were identical, but as the discharge rate was increased, a more rapid decline in capacitance was observed for the perpendicular orientation (66 vs 14% decline in capacitance when the discharge current was increased from 0.01 to 1 A/g). Furthermore, the maximum power rating of the perpendicular electrode was lower than that of the parallel electrode (1.85 vs 3 kW/kg during operation at 1 V). 相似文献