共查询到17条相似文献,搜索用时 359 毫秒
1.
2.
二次阳极氧化法制备多孔氧化铝膜 总被引:1,自引:0,他引:1
文章介绍采用二次阳极氧化法制备孔洞规则、有序的多孔氧化铝膜的工艺。多孔阳极氧化铝(AAO)膜孔径为20~100nm,孔道相互平行且垂直于表面,深度可达50μm。详细分析了第1次阳极氧化、去除氧化层、第2次阳极氧化、扩孔过程中孔结构发生的变化。研究了不同电解液、阳极氧化温度、外加电压等对多孔氧化铝结构的影响。分析了多孔氧化铝膜的表面及侧面形貌、表面微区成分。在草酸溶液中氧化所得的AAO膜孔径相对在硫酸溶液中的较大。在一定范围内,增加氧化温度及氧化电压能提高AAO膜孔径。 相似文献
3.
4.
本文采用掠入射中子小角散射(GISANS)技术,研究了沉积在多孔阳极氧化铝(AAO)模板中的Co磁性纳米线阵列的空间结构,利用计算机软件对GISANS实验进行了理论模拟,并与扫描电子显微镜(SEM)观察的结果进行比较。结果表明,GISANS实验结果、GISANS理论模拟结果和SEM实验结果三者相吻合。纳米线直径约为60 nm,纳米线中心平均距离约为121 nm,垂直于样品表面相互平行排列,在样品平面内呈现出二维局域六角有序排布。本工作证明了GISANS实验技术结合计算机理论模拟,是研究纳米线阵列及类似纳米体系的有力手段。 相似文献
5.
利用阳极氧化法制备的氧化铝薄膜是非晶态的并且表面呈高度有序的多孔结构.经过太阳光照射后氧化铝薄膜具有明显的热释光现象,发光峰值出现在190℃,表明其对太阳光敏感.经过电子束辐照后薄膜的热释光特性与制备时电解液浓度和退火处理的时间有关,其中制备过程中电解液浓度为0.4mol/L热释光现象最明显,退火时间为5小时的热释光现象最明显. 相似文献
6.
7.
8.
~(99)Mo的衰变子体核素~(99m)Tc是核医学中应用最为广泛的放射性同位素,其使用量约占所有放射性同位素的70%。基于对目前国内外~(99)Mo制备方法的文献调研,阐述了医用~(99)Mo的主要制备方法,包括反应堆生产~(99)Mo、加速器制备~(99)Mo和中子发生器制备~(99)Mo。从靶件形式与化学提取等方面重点分析了以高浓铀(HEU)或低浓铀(LEU)为靶材料,利用反应堆生产裂变~(99)Mo的方法。鉴于近年来使用加速器与中子发生器制备~(99)Mo的方法已取得了较大进展,本文亦对此进行了较详细的阐述,并对进一步的研究工作提出建议。 相似文献
9.
结合模板法和原位生长法制备了新型吸附与离子交换性能兼备的Ni-Fe(Ⅱ)普鲁士蓝/碳纳米管海绵,并通过稳定同位素铯模拟放射性核素研究了材料对Cs+的去除效果。实验结果表明:复合材料很好地复制了聚氨酯海绵的三维开架多孔结构,在孔壁上沉积了大量碳纳米管,并在其表面生长了具有优异离子交换性能的Ni-Fe(Ⅱ)普鲁士蓝纳米颗粒,其占样品总量的1.38%。对Cs+的去除实验结果表明:Ni-Fe(Ⅱ)普鲁士蓝/碳纳米管海绵对Cs+有良好的去除能力;全谱等离子直接光谱仪(ICP)元素分析和穆斯堡尔谱研究表明,Ni-Fe(Ⅱ)普鲁士蓝中的K+与Cs+间发生了离子交换反应,材料对Cs+的吸附容量为698 μg/g。 相似文献
10.
11.
Ruiting Zheng Yong Zhao Kimberlee Collins 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(6):568-572
Polished Si substrates are sputtered by He+ ions, and carbon nanotube arrays are prepared on the Fe-coated substrates by heat chemical vapor deposition from acetylene. Scanning electron microscopy and atomic force microscopy are employed to examine the morphologies of sputtered substrates, catalyst and carbon nanotube arrays. It is found that ion sputtering is effective in increasing the roughness of Si substrates, and helpful in obtaining higher density Fe catalyst particles and better-aligned carbon nanotube arrays. 相似文献
12.
Jian-hua DengZhao-xia Ping Rui-ting ZhengGuo-an Cheng 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(10):1082-1087
Field emission characteristics of carbon nanotube arrays synthesized by thermal chemical vapor deposition on iron ion pre-bombarded silicon substrate are enhanced by titanium ion irradiation. A pronounced degradation of turn-on electric field of 0.305 V/μm and threshold field, of which the lowest value is only 1.054 V/μm, about 0.482 V/μm at the dose of 5 × 1016 ions/cm2 is as an expression of this enhancement. Scanning electron microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, Photoelectron spectrometer and transmission electron microscopy are measured for comparison before and after the Ti ion irradiation of the carbon nanotube arrays, and the results reveal that the formation of carbon nanorod/nanotube heterostructure during ion irradiation plays a dominative role in the promotion of the field emission properties. However, high-dose irradiating transaction on carbon nanotube arrays will exert repulsive effects on the field emission characteristics for the introduction of severe structural damage. Additionally, the longtime eminent stability behaviors under high applied fields have provided a possibility for the potential application of field emission flat panel display or electron emitters based on carbon nanotube arrays. 相似文献
13.
Zhichun Ni Qintao Li Jinlong Gong Dezhang Zhu Zhiyuan Zhu 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2007,260(2):542-546
Multi-walled carbon nanotubes (MWCNTs) were irradiated by 40 keV Si ion beam with different doses. The structural change of the MWCNTs was revealed by transmission electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy. The structural characterization after irradiation shows that the formation of amorphous carbon nanowires proceeds through two periods, carbon nanotube – semi-solid amorphous carbon nanowire with hollow structure – solid amorphous carbon nanowire. Based on the interaction between energetic particles and carbon nanotubes, the structural transformation process and corresponding mechanisms are discussed. A model is presented to illustrate the structural change of carbon nanotubes with increased irradiation dose. 相似文献
14.
It is reported that the highly dispersed Pt nanoparticles on carbon nanotubes can be synthesized under mild conditions by in situ plasma treatment.The carbon nanotube was pretreated by O2 plasma to transform into oxide carbon nanotubes(O-CNTs),and then it was mixed with the precursors(the mixture of H2 PtCl6and PdCl6).After that,the O-CNTs and the precursors were simultaneously treated by H2 plasma.The precursors were transformed into Pt-Pd nanoparticles(NPs)and the O-CNTs transformed into CNT.The synthesized CNT-based Pt-Pd nanoparticles were characterized by scanning electron microscopy,transmission electron microscopy,X-ray diffraction and X-ray photoelectron spectroscopy.All the analysis showed that the Pt-Pd nanoparticles were deposited on CNT as a form of face-centered cubical structure. 相似文献
15.
M. González R. Román C. Maffiotte J. González-Casablanca R. Perez D. Hole 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(8-9):1468-1471
As candidate materials for future thermonuclear fusion reactors, isolating ceramics will be submitted to high energy gamma and neutron radiation fluxes together with an intense particle flux. Amorphization cannot be tolerated in ceramics for fusion applications, due to the associated volume change and the deterioration of mechanical properties. Therefore, a comprehensive study was carried out to examine the effects of carbon beam irradiation on polycrystalline aluminium oxide (Al2O3), a ceramic component of some diagnostic and plasma heating systems. Complementary techniques have allowed a complete chemical and structural surface analysis of the implanted alumina. Implantation with 75 keV, mono-energetic carbon ions at doses of 1 × 1017 and 5 × 1017 ions/cm2 was performed on polished and thermally treated ceramic discs. The alumina targets were kept below 120 °C. The structural modifications induced during ion irradiation were studied by the GXRD and TEM techniques. Under these conditions, alumina is readily amorphized by carbon ions, the thickness of the ion-beam induced disordered area increasing with the ion dose. Matrix elements and ion implanted profiles were followed as a function of depth by using ToF-SIMS, indicating the maximum concentration of implanted ions to be in the deeper half of the amorphous region. Ion distribution and chemical modifications caused in the Al2O3 substrate by carbon irradiation were corroborated with XPS. The amount of oxygen in the vicinity of the implanted alumina surface was reduced, suggesting that this element was selectively sputtered during carbon irradiation. The intensity of those peaks referring to Al–O bonds diminishes, while contributions of reduced aluminium and metal carbides are found at the maximum of the carbon distribution. TEM observations on low temperature thermally annealed specimens indicate partial recovery of the initial crystalline structure. 相似文献
16.
衰减法测量静电加速器电子束能量 总被引:2,自引:2,他引:0
研制了薄壁平行板透射电离室,研究了透射电离室的特性。用透射电离室测量静电加速器电子束在铝中的透射分布,得到不同高压下电子束在铝中的外推射程,进而确定电子束能量。 相似文献
17.
D.J. Mowbray Sangwoo Chung Z.L. Mikovi F.O. Goodman You-Nian Wang 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2005,230(1-4):142-147
We used the hydrodynamic model to describe the dielectric response of a multi-walled carbon nanotube to a fast point charge moving paraxially, either inside or outside the nanotube. Calculations are performed for a two-walled nanotube, giving rise to a splitting of the plasmon frequencies due to the interaction between the electron fluids on the two cylinders. The dependences of the projectile stopping power and the self-energy (image potential) on the velocity and the distance from the nanotube axis show interesting features when the projectile velocity matches the phase velocity of the plasmon mode with a quasi-linear dispersion. 相似文献