نتایج جستجو برای: single walled boron nitride nanotubes

تعداد نتایج: 923923  

2014
Fernando Gomes Victor Dmitriev Clerisson Nascimento

The pristine boron nitride nanotubes have a large direct band gap around 5 eV. This band gap can be engineered by doping. We investigate electronic structure of the doped hexagonal boron nitride (5,5) nanotubes using the linearized augmented cylindrical wave method. In particular, this work focuses on systematical study of the band gap and the density of states around the Fermi-level when the n...

2010
Zhaohui Dong Yang Song

Multiwalled boron nitride nanotubes (BNNTs) were compressed at room temperature in diamond anvil cells up to 35 GPa, followed by decompression. For the first time, in situ infrared absorption spectroscopy was used to monitor BNNT structural transformations. These BNNTs were found to undergo pressure-induced transformations from a hexagonal to a more closely packed wurtzite structure at 11 GPa, ...

2011
Tiago Hilário Ferreira Paulo Roberto Omelas da Silva Raquel Gouvêa dos Santos Edésia Martins Barros de Sousa

Nanostructures of boron nitride have attracted a great deal of interest due to their potential applications that comprise a broad range of topics, including biomedical technology, since it presents good chemical stability and suggests good biological inertia. This paper reports a facile and effective synthesis based on CVD process with new conditions to produce boron nitride nanotubes in higher...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1391

in this thesis, we exploit a simple and suitable method for immobilization of copper(ii) complex of 4?-phenyl-terpyridine on activated multi-walled carbon nanotubes [amwcnts-o-cu(ii)-phtpy]. this nanostructure was characterized by various physico-chemical techniques. to ensure the efficiency and fidelity of copper species, the implementation of three-component strategies in click-chemistry all...

Interaction of pure and Vn-doped (8, 0), (12, 0) and (16, 0) boron nitride nanotubes with CO molecules was studied using B3LYP/6-311++G(d) theoretical level. Substituting V instead of B atoms, increased the reactivity of nanotube. From the results, the complex stability depends on the direction and the number of the CO molecules interacted with the nanotube. In this work, the quantum...

2016
Leonid Gilburd Xiaoji G. Xu Yoshio Bando Dmitri Golberg Gilbert C. Walker

Surface phonon-polariton (SPhP) modes exist under optical excitation of polar materials, and are accessible using scattering type near-field optical microscopy (s-SNOM). Hexagonal boron nitride (hBN) and boron nitride nanotubes (BNNTs) can exhibit such modes under IR excitation, in spectral regions where the permittivity is negative. Herein we present pump-probe continuous wave (CW) sSNOM a nov...

حاج آقازاده, محمد, شاه طاهری, سید جمال الدین, صبور یراقی, علی اکبر, محمدیان, یوسف, کاکویی, حسین,

Background and aim: In this study the cytotoxicity to human epithelial lung cells of single-walled carbon nanotubes, multi-walled carbon nanotubes and chrysotile was compared based on the following cytotoxicity indices: no observable adverse effect concentration (NOAEC), inhibitory concentration 50 (IC50), and Total Lethal Concentration (TLC). Materials and Methods: Human epithelial lung cells...

Journal: :Nano letters 2005
Jiesheng Wang Vijaya K Kayastha Yoke Khin Yap Zhiyong Fan Jia G Lu Zhengwei Pan Ilia N Ivanov Alex A Puretzky David B Geohegan

High growth temperatures (>1100 degrees C), low production yield, and impurities have prevented research progress and applications of boron nitride nanotubes (BNNTs) in the past 10 years. Here, we show that BNNTs can be grown on substrates at 600 degrees C. These BNNTs are constructed of high-order tubular structures and can be used without purification. Tunneling spectroscopy indicates that th...

Journal: :Nanotechnology 2008
Chee Huei Lee Jiesheng Wang Vijaya K Kayatsha Jian Y Huang Yoke Khin Yap

Effective growth of multiwalled boron nitride nanotubes (BNNTs) has been obtained by thermal chemical vapor deposition (CVD). This is achieved by a growth vapor trapping approach as guided by the theory of nucleation. Our results enable the growth of BNNTs in a conventional horizontal tube furnace within an hour at 1200 °C. We found that these BNNTs have an absorption band edge of 5.9 eV, appro...

2007
Jason P. Moscatello Jiesheng Wang Benjamin Ulmen Vijaya K. Kayastha Ming Xie Samuel L. Mensah Shun Wu Archana Pandey Chee Huei Lee Abhishek Prasad Yoke Khin Yap

Nanotubes have significant portions of their atoms located at the surfaces and represent the future of biological devices. With such small dimensions, sensitivities and applications previously impossible are being made real. Not all nanomaterials are currently at the same level of proficiency, however. Carbon nanotubes are a mature, easily grown and controlled nanostructure, but boron nitride a...

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