http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Analyzing the Purity of Carbon Nanotubes by Using Different Methods
Ngo Thi Thanh Tam,Nguyen Xuan Nghia,Nguyen The Quynh,Phan Hong Khoi,Phan Ngoc Minh 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
The purity of carbon nanotubes (CNTs) was evaluated by using a variety of methods: X-ray diraction, Raman spectroscopy, thermogravimetric analysis and energy dispersive X-ray uores- cence spectroscopy. X-ray diffraction, Raman spectroscopy and thermogravimetric analysis were used for a qualitative evaluation of impurities and energy dispersive X-ray uorescence spectroscopy was utilized for a quantitative determination. All experimental results evaluating the purity ob- tained from these techniques are consistent with each other for CNT samples with different degrees of purity. The purity of the CNT samples was found to be greatly increased when they were annealed in air or in vacuum. The contributions of Si-related, crystalline carbon, non-crystalline carbon and Fe and Ni components are discussed. The purity of carbon nanotubes (CNTs) was evaluated by using a variety of methods: X-ray diraction, Raman spectroscopy, thermogravimetric analysis and energy dispersive X-ray uores- cence spectroscopy. X-ray diffraction, Raman spectroscopy and thermogravimetric analysis were used for a qualitative evaluation of impurities and energy dispersive X-ray uorescence spectroscopy was utilized for a quantitative determination. All experimental results evaluating the purity ob- tained from these techniques are consistent with each other for CNT samples with different degrees of purity. The purity of the CNT samples was found to be greatly increased when they were annealed in air or in vacuum. The contributions of Si-related, crystalline carbon, non-crystalline carbon and Fe and Ni components are discussed.
Carbon-Nanotube Growth over Iron Nanoparticles Formed on CaCO3 Support by Using Hydrogen Reduction
Nguyen Duc Dung,Nguyen Van Chuc,Ngo Thi Thanh Tam,Nguyen Hong Quang,Phan Hong Khoi,Phan Ngoc Minh 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
Carbon nanotubes (CNTs) were grown by chemical vapor deposition on a mixture of iron salt and CaCO3. Salt mixtures of Fe(NO₃)₃9H₂O/CaCO₃ and FeCl₃6H₂O/CaCO₃ with various Fe weight contents were used as catalysts for growing the CNTs. A scanning electron microscope study revealed that the CNTs were densely grown on the Fe(NO₃)₃9H₂O/CaCO₃ catalyst containing 5 wt.% Fe. The effect of growth temperature on the segregation of Fe nanoparticles formed by hydrogen reduction is discussed. The result shows that 800 ℃ is the optimal temperature for the formation of Fe nanoparticles over which CNTs grow with the highest yield of 78.61 %. A raman spectroscope and a scanning transmission electron microscope were utilized to characterize the multiwall structure of the CNTs. The 92.16 % purity of the CNTs was determined by using thermal gravimetric analysis. Carbon nanotubes (CNTs) were grown by chemical vapor deposition on a mixture of iron salt and CaCO3. Salt mixtures of Fe(NO₃)₃9H₂O/CaCO₃ and FeCl₃6H₂O/CaCO₃ with various Fe weight contents were used as catalysts for growing the CNTs. A scanning electron microscope study revealed that the CNTs were densely grown on the Fe(NO₃)₃9H₂O/CaCO₃ catalyst containing 5 wt.% Fe. The effect of growth temperature on the segregation of Fe nanoparticles formed by hydrogen reduction is discussed. The result shows that 800 ℃ is the optimal temperature for the formation of Fe nanoparticles over which CNTs grow with the highest yield of 78.61 %. A raman spectroscope and a scanning transmission electron microscope were utilized to characterize the multiwall structure of the CNTs. The 92.16 % purity of the CNTs was determined by using thermal gravimetric analysis.
New Technique for the Synthesis of Carbon Nanotubes
Phan Ngoc Minh,Phan Hong Khoi,Nguyen Van Chuc,Phan Ngoc Hong,Ngo Thi Thanh Tam 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5
Carbon nanotubes (CNTs) are considered as a promising material for various applications. However, due to their limited availability and high purchasing costs, at the present time, only a few of these applications have been realized. The realization of CNT-based devices and CNT-based materials depends on success in material synthesis and on the possibility of controlling the nanotube's chirality, diameter and purity. This paper describes new simple techniques for (i) synthesis of vertically-aligned carbon nanotubes (VA-CNTs), (ii) mass and low-cost production of multiwall carbon nanotubes (MWCNTs) and (iii) growth of individual CNTs on tungsten tips.