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1.
刻线镍膜上沉积的碳纳米管场发射特性 总被引:8,自引:3,他引:5
利用微波等离子体化学气相沉积(MWPCVD)方法,在刻线的镍膜上沉积碳纳米管膜。通过SEM和拉曼光谱表征,讨论了催化剂厚度、制备温度、反应时间以及甲烷浓度对碳纳米管场发射的影响。结果表明:不同条件下制备的碳纳米管的场发射性能有很大差异,保持氢气的流量(100sccm)不变,当甲烷流量为5sccm、生长时间为5min、催化剂膜厚为150nm、温度为700~800℃时,场发射性能最好,开启场强为1.3V/um,最大发射电流达到6.8mA/cm^3。 相似文献
2.
碳纳米管的纯化及其在聚乙烯醇中的分散 总被引:3,自引:0,他引:3
采用硫酸和硝酸混合酸对多壁碳纳米管(MWNTs)进行纯化,利用红外光谱(IR)、X射线衍射(XRD)对MWNTs进行了表征;聚乙烯醇/乙醇(V/V=1:1)溶液分散MWNTs,循环伏安法(CV)测试了碳纳米管/聚乙烯醇膜修饰电极的电化学性能.实验结果表明,混酸处理可以提高碳纳米管的纯度及石墨化程度,并可以在碳纳米管上引入羧基功能团;碳纳米管可以均匀地分散在聚乙烯醇/乙醇溶液中并形成稳定的悬浮液,同时碳纳米管/聚乙烯醇膜修饰电极对苯二酚具有明显电化学催化活性. 相似文献
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本文叙述了痕量铍在铝合金中的重要作用以及石墨炉原子吸收光谱法测定铝合金中痕量铍的方法研究。该方法用硝酸(1+1)溶解样品。0.10mg/mL以上的铝具有增感效应,铍在0-0.25μg/100mL的范围内具有良好线性关系。该方法操作简便、灵敏度高,特征浓度为1.05×10 ̄(-5)μg/mL/1%。相对标准偏差为1.66%,回收率在96%-102.5%。 相似文献
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基于蒙特卡罗粒子输运程序MCNP,设计了一种强度高、密度低、具有优异中子屏蔽性能的新型玻璃纤维/B4C/环氧树脂复合材料,模拟计算了镅-铍(Am-Be)中子源产生中子对该材料的透射率;研究了该材料的中子屏蔽性能与传统屏蔽材料的差异以及不同B4C质量分数对该材料的屏蔽性能影响;根据模拟结果分析了该材料对不同能区中子(慢中子、中能中子、快中子)具有的不同屏蔽性能。研究发现:B4C质量分数为10%的该种新型玻璃纤维/B4C/环氧树脂复合材料的中子屏蔽性能,尤其是慢中子屏蔽性能较传统的含硼聚乙烯和Al-B4C合金材料更为优异;但随着B4C质量分数的增大,屏蔽性能提升不明显。结果验证了蒙特卡罗方法用于中子屏蔽材料优化设计的可行性。 相似文献
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用原位聚合法制备了聚吡咯/碳纳米管( PPy/MWNTs)复合物.采用XRD、TGA、FT-IR、SEM、四探针测试仪和网络分析仪表征了PPy/MWNTs复合物的组成、结构、形貌和电性能.研究了不同制备条件,如质子酸及其浓度、MWNTs的质量分数(ωMWNTs )、引发剂和单体的物质的量比( nAPS/nPy )和反应时间对PPy/MWNTs复合物电性能的影响.结果表明,当磷酸浓度为0.1 mol/L、nAPS/nPy为1:1、ωMWNTs等于45 wt%、反应时间12 h时,制备的PPy/MWNTs复合物的导电性和介电损耗性能最好. 相似文献
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石墨炉原子吸收光谱法测定质子交换膜燃料电池(PEMFC)膜电极中铂含量 总被引:1,自引:0,他引:1
付川 《光谱学与光谱分析》2004,24(9):1130-1132
质子交换膜燃料电池膜电极中铂催化剂的含量对于电极的成本和性能是非常重要的,文章以石墨炉原子吸收光谱法测定了膜电极中铂的含量,探讨了石墨炉升温程序及实验方法的最佳工作条件。该方法准确、快速和简便。回收率在97.3%~101.2%之间,相对偏差小于2.67%。 相似文献
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以二茂铁、二甲苯为前驱体,石英为衬底,在850 oC的管式炉内采用化学气相沉积法制备出了定向碳纳米管阵列. 高分辨透射电子显微镜和拉曼光谱的结果表明:碳纳米管阵列具有良好的定向性和多壁管状结构,石墨化程度高,并且只在表面存在少量单壁碳纳米管.定向多壁碳纳米管阵列的生长模式为“底部”生长模式,即在生长的初期,当催化剂颗粒较小时,析出的碳原子生成了单壁碳纳米管或与其性质类似的多壁碳纳米管(一般层数小于5层);催化剂颗粒逐渐长大后,大量的碳原子析出后生成了普通的多壁碳纳米管,从而形成了单壁碳纳米管只存在于碳纳米管阵列膜表面和多层碳纳米管膜表面与界面的现象. 相似文献
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文章介绍弛一种利用恒载荷速率加载测试金刚石膜断裂性能的试验方法,并建立了国内第一台金刚石膜断裂性能测试的专用装置,该装置利用弹性压头代替传统的刚性压头,可以成功地解决断裂试验的缓慢加载问题,试验装置的最大载荷为500N,可以在5-500N之间获得准确的载荷,误差不大于1%,最小加载速率为0.5N/s,最大加载速率为25N/s,该装置采用计算机控制,可以直接输出试验结果,该装置采用恒载荷速率(0.5N/s 至2N/s)的加载方式测得的断裂性能比用恒位移速率(0.5mm/min和0.05mm/min)加载方式测得的断裂性能更低,适合高脆性,小尺寸金刚石膜试样断裂性能的测试。 相似文献
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A. N. Obraztsov A. P. Volkov A. I. Boronin S. V. Koshcheev 《Journal of Experimental and Theoretical Physics》2001,93(4):846-852
The field electron emission, structural features, and electronic properties of carbon films obtained by chemical vapor deposition were experimentally studied. It is shown that the field electron emission from the films composed of spatially oriented carbon nanotubes and platelike graphite nanocrystals is observed for the electric field strength lower by one to two orders of magnitude as compared to the values characteristic of the metal emitters. Experimental data reported for the first time are indicative of a local decrease in the electron work function in such carbon film materials as compared to that in graphite. A model of the emission center is proposed and a mechanism of the field electron emission from nanostructured carbon is described. 相似文献
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碳纳米管具有优异的导电性, 是未来电子元器件的理想候选材料, 应用前景广阔. 针对碳纳米管在空间电子元器件的应用需求, 本文研究了170 keV质子辐照对多壁碳纳米管薄膜微观结构与导电性能的影响. 采用扫描电子显微镜(SEM)、拉曼光谱仪(Raman)、X射线光电子能谱仪(XPS)及电子顺磁共振谱仪(EPR)对辐照前后碳纳米管试样的表面形貌和微观结构进行分析; 利用四探针测试仪对碳纳米管薄膜进行导电性能分析. SEM分析表明, 170 keV质子辐照条件下, 当辐照注量高于5×1015 p/cm2 (protons/cm2)时, 碳纳米管薄膜表面变得粗糙疏松, 纳米管发生明显弯曲、收缩及相互缠结现象. 目前, 质子辐照纳米管发生的收缩现象被首次发现. 基于Raman和XPS分析表明, 170 keV质子辐照后碳纳米管的有序结构得到改善, 且随辐照注量增加, 碳纳米管的有序结构改善明显. 结构的改善主要是由于170 keV质子辐照碳纳米管所产生的位移效应导致缺陷重组. EPR分析表明, 随着辐照注量的增加, 碳纳米管薄膜内的非局域化电子减少. 利用四探针测试分析表明, 碳纳米管薄膜的导电性能变差, 这是由于170 keV质子辐照导致碳纳米管薄膜中的电子特性及形态发生改变. 本文研究结果有助于利用质子辐照对碳纳米管膜结构和性能进行调整, 从而制备出抗辐射的纳米电子器件. 相似文献
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N. V. Sopinskii V. S. Khomchenko O. S. Litvin A. K. Savin N. A. Semenenko A. A. Evtukh V. P. Sobolevskii G. P. Ol’khovik 《Technical Physics》2011,56(11):1665-1669
The properties of low-refractive-index carbon films obtained by close-spaced vapor transport at graphite sublimation are studied.
The optical properties of the films are investigated by monochromatic multiple-angle ellipsometry, and their morphology is
examined by AFM. It is found that the films have a columnar structure with a background surface roughness of about 1 nm. In
addition, the surface of the film contains islands up to 50 nm in height with a footprint of ≈200 nm. A low-refractive-index
carbon film deposited by close-spaced vapor transport on silicon tips is found to decrease the field emission threshold and
drastically raise the current. 相似文献
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F. Bonaccorso C. Bongiorno P.G. Gucciardi A. Morone C. Spinella 《Applied Surface Science》2007,254(4):1260-1263
The physical/chemical properties of multiwalled carbon nanotubes have attracted much interest for applications in different fields, from micro-electronic to coating technology due, in particular, to their peculiar conductivity properties, to their hardness and high resistance to thermal stress. The technology to produce carbon nanotubes thin films with the desired properties, however, is still under development. In this work, we report on multiwalled carbon nanotubes thin films deposited by pulsed laser deposition techniques ablating commercially polystyrene-nanotubes pellets on alumina substrates. MicroRaman spectroscopy and high resolution Transmission Electron Microscopy provide the experimental confirmation that carbon nanotubes-like structures are present on the alumina surface with both minimal morphological damage of the tubes and structural changes induced by laser beam. 相似文献
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Research into amorphous carbon films has been developed to such an extent that the film property can be fine tuned to mimic that of the crystalline counterparts, be it diamond, graphite, or even fullerene-like. This flexibility makes such films ideal for a wide range of applications from anti-abrasive window coating to lubricating layers on the surface of magnetic hard-disk. Not only are their mechanical properties interesting, electrically the diamond-like amorphous carbon films are also easier to dope than crystalline diamond, making them potentially a better alternative to amorphous silicon for photovoltaic devices. We will show that electron energy loss spectroscopy, in particular the carbon 1s core absorption spectroscopy, has been instrumental in revealing the nature of the bonding between carbon atoms. Such information allows microstructure models to be developed for proper understanding of the observed properties and providing scientific basis for future improvement. 相似文献
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A. A. Zolotukhin A. N. Obraztsov A. O. Ustinov A. P. Volkov 《Journal of Experimental and Theoretical Physics》2003,97(6):1154-1158
Deposition of carbon materials from methane-hydrogen gas mixtures in a DC gas discharge is investigated. Parameters ensuring stable discharge conditions and synthesis of diamond and graphite-like films are determined. Optical emission spectroscopy is used to analyze the composition of the activated gas phase in the course of carbon film deposition. Synthesis of graphite-like carbon nanotubes and nanocrystallites is shown to correlate with the presence of C2 dimers in the plasma. A noncatalytic mechanism of synthesis of nanostructured graphite in a carbon-containing gas phase is proposed. 相似文献
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Anisotropic optical absorption properties of single-walled carbon nanotubes (SWNTs) are determined from a vertically aligned SWNT film for 0.5-6 eV. Absorption peaks at 4.5 and 5.25 eV are found to exhibit remarkable polarization dependence and have relevance to optical properties of graphite. A method for determining a nematic order parameter for an aligned SWNT film based on the collinear absorption peak at 4.5 eV is presented, followed by the determination of the optical absorption cross section. 相似文献
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E. M. Malykhin V. A. Krivchenko D. V. Lopaev T. V. Rakhimova S. M. Zyryanov 《Moscow University Physics Bulletin》2011,66(1):54-58
In this work, the structure and chemistry of thin nm-thick carbon films deposited on a substrate using strong 13.5 nm EUV
irradiation under a strong vacuum were studied. The film structure was studied by Raman spectroscopy in comparison with the
Raman spectra of well-known carbon phases: diamond, single-wall nanotubes, nano- and micro-crystalline graphite and amorphous
carbon. As well, FTIR spectroscopy was used to study possible IR-active chemical bonds, primarily, hydrogen bonds. It was
shown that films deposited on a surface under EUV irradiation consists of amorphous sp
2-carbon. The mechanisms of deposition are discussed briefly. Knowledge about the structure and chemistry of such carbon films
is very important for EUV lithography. 相似文献