Artykuły w czasopismach: „ARMCHAIR TYPE NANOTUBE”

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Дадашян, Л. Х., Р. Р. Трофимов, Н. Н. Конобеева i М. Б. Белоненко. "Предельно короткие импульсы в оптически анизотропной среде, содержащей углеродные нанотрубки с металлической проводимостью". Оптика и спектроскопия 130, nr 12 (2022): 1861. http://dx.doi.org/10.21883/os.2022.12.54092.49-22.

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In this work, we study the interaction of extremely short pulses with a nonlinear anisotropic optical medium with carbon nanotubes (armchair and zigzag type) with metallic conductivity. The dependence of the pulse shape, width, and intensity on the nanotube chirality indices is analyzed. The most appropriate type of carbon nanotubes is substantiated for providing localized propagation of an electromagnetic field in a medium with anisotropic properties.

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Dadashyan L.H., Trofimov R.R., Konobeeva N.N. i Belonenko M.B. "Extremely short pulses in an anisotropic optical medium containing carbon nanotubes with metal conduction". Optics and Spectroscopy 130, nr 12 (2022): 1587. http://dx.doi.org/10.21883/eos.2022.12.55246.49-22.

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In this work, we study the interaction of extremely short pulses with a nonlinear anisotropic optical medium with carbon nanotubes (armchair and zigzag type) with metallic conductivity. The dependence of the pulse shape, width, and intensity on the nanotube chirality indices is analyzed. The most appropriate type of carbon nanotubes is substantiated for providing localized propagation of an electromagnetic field in a medium with anisotropic properties. Keywords: optical anisotropy, extremely short pulse, carbon nanotubes, metallic conduc.

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Malysheva, Lyuba. "Effects of chirality in the electron transmission through step-like potential in zigzag, armchair, and (2m,m) carbon nanotubes". Low Temperature Physics 48, nr 11 (listopad 2022): 907–13. http://dx.doi.org/10.1063/10.0014581.

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We report the one-electron spectrum and eigenstates of infinite achiral and chiral (2 m, m) carbon nanotubes found by using the analytic solution to the Schrödinger equation for the tight-binding Huckel-type Hamiltonian. With the help of matching the wave functions on the interfaces between the regions, where electrons have different site energies, we find and compare the transmission coefficients for zigzag, armchair and chiral nanotubes subjected to the action of an applied step-like potential. The correspondence between the nanotube band structure and the energy dependence of the transmission coefficient is demonstrated. It is shown that the (2 m, m) nanotubes with a medium chiral angle reveal intermediate transport properties as compared with the achiral armchair, and zigzag nanotubes.

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Tomilin O. B., Rodionova E. V., Rodin E.A., Poklonski N. A., Anikeyev I. I. i Ratkevich S. V. "Dependence of the energy of emission molecular orbitals in short open carbon nanotubes on the electric field". Physics of the Solid State 64, nr 3 (2022): 347. http://dx.doi.org/10.21883/pss.2022.03.53191.201.

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On the examples of short open carbon nanotubes of armchair type (n,n), for n=3, 4, and zigzag (n,0), for n=5, 6, 7, the influence of the magnitude and direction of the external constant electric field vector on their field emission properties was studied. It is shown that the deviation of the field vector from the nanotube axis leads to an increase in the field strength to generate electron field emission. Emission orbitals in carbon nanotubes (n,n) found as a result of a new type of conjugation of p-electrons in cylindrical conjugated systems are more sensitive to a change in the direction of the electric field vector compared to emission orbitals in nanotubes (n,0). When the electric field vector deviates from the nanotube axis, the emission orbitals of carbon nanotubes change the less, the larger the nanotube diameter. Keywords: short open carbon nanotubes, field emission, conjugation of p-electrons, emission molecular orbital.

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LU, S., C. D. CHO i L. SONG. "ENERGY OF ARMCHAIR NANOTUBE USING THE MODIFIED CAUCHY-BORN RULE". International Journal of Modern Physics B 22, nr 31n32 (30.12.2008): 5881–86. http://dx.doi.org/10.1142/s0217979208051315.

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Due to the difference of nanotube diameters, the single-walled carbon nanotubes (SWCNTs) show the different energy and mechanical properties. In order to take the effect of the curvature of nanotubes into account in the modeling of those structures, the present paper proposes an atomistic based continuum model with using a type of modified Cauchy-Born to link the continuum strain energy to the interatomic potential. This modified Cauchy-Born is developed by incorporating the concept of differential mean value theorem into the standard Cauchy-Born rule. The present model not only can bridge the microscopic and macroscopic length scales, but also can investigate the curvature effect of a single layer film on the continuum level. Application of the current model to armchair carbon nanotubes and graphite shows an excellent prediction of the size dependent strain energy which are compared in a good agreement with the existing experimental and theoretical results.

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Yao, Tieguang, Hao Yu, Rudolf J. Vermeij i Graham J. Bodwell. "Nonplanar aromatic compounds. Part 10: A strategy for the synthesis of aromatic belts-all wrapped up or down the tubes?" Pure and Applied Chemistry 80, nr 3 (1.01.2008): 533–46. http://dx.doi.org/10.1351/pac200880030533.

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A strategy for the synthesis of cyclophenacene-type aromatic belts (or armchair nanotube segments) that relies upon a valence isomerization/dehydrogenation reaction is described, and progress toward achieving this goal is presented.

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Bocko, Jozef, Pavol Lengvarský, Róbert Huňady i Juraj Šarloši. "The computation of bending eigenfrequencies of single-walled carbon nanotubes based on the nonlocal theory". Mechanical Sciences 9, nr 2 (1.11.2018): 349–58. http://dx.doi.org/10.5194/ms-9-349-2018.

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Abstract. In this work, a recently proposed nonlocal theory of bending is used in the analysis of eigenfrequencies of single-walled carbon nanotubes (SWCNTs). The nanotube vibration is analyzed in the form of a homogenized continuum. Classical treatment where a nanotube is approximated by standard beam theory, is replaced by the more sophisticated nonlocal method of material interactions where a nonlocal parameter is used. The eigenfrequencies are computed by the combination of analytical as well as numerical methods for four different carbon nanotube (CNT) supports. Various types of supports are considered for the analysis: fixed–simply supported, fixed–free, simply–simply supported and fixed–fixed. Due to the huge amount of computed data, only outcomes of eigenfrequency computations for the nanobeams of armchair type with fixed and simply supported ends, and different nonlocal parameters are represented in the form of graphs at the end of the article. The study shows how the nanotube eigenfrequencies depend on nonlocal parameters as well as on the length and diameter of CNTs. The obtained results are in good agreement with the results published in papers which were gained by different procedures.

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Okuyama, Rin, Wataru Izumida i Mikio Eto. "Topology in single-wall carbon nanotube of zigzag and armchair type". Journal of Physics: Conference Series 969 (marzec 2018): 012137. http://dx.doi.org/10.1088/1742-6596/969/1/012137.

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Jadi, Supri, i A. Setiadi. "Structural Shifting and Electronic Properties of Stone-Wales Defect in Armchair Edge (5,5) Carbon Nanotube". Advanced Materials Research 772 (wrzesień 2013): 380–85. http://dx.doi.org/10.4028/www.scientific.net/amr.772.380.

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Stone Wales (SW) defect is one type of topological defect on the CNT, in this study we performed first principles calculations of SW defects in armchair edge (5,5) carbon nanotube (CNT) by the density functional theory (DFT). Two different defects were studied such as longitudinal and circumference types. Our calculation results show that a longitudinal SW defect is more stable than circumference SW defect. However barrier energy as parameter to control the SW defect in CNT was studied, in calculation we applied Nudge Elastic Band (NEB) method to find minimum energy path (MEP) and barrier energy for SW defect transitions. The result shows that barrier energy of circumference SW defect is lower than another one. We also found that in the case of circumference SW defect, armchair edge (5,5) CNT become semiconductor with the band gap of 0.0544 eV.

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Selvamani, Rajendran, M. Mahaveer Sree Jayan, Rossana Dimitri, Francesco Tornabene i Farzad Ebrahimi. "Nonlinear magneto-thermo-elastic vibration of mass sensor armchair carbon nanotube resting on an elastic substrate". Curved and Layered Structures 7, nr 1 (7.10.2020): 153–65. http://dx.doi.org/10.1515/cls-2020-0012.

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AbstractThe present paper aims at studying the nonlinear ultrasonic waves in a magneto-thermo-elastic armchair single-walled (SW) carbon nanotube (CNT) with mass sensors resting on a polymer substrate. The analytical formulation accounts for small scale effects based on the Eringen’s nonlocal elasticity theory. The mathematical model and its differential equations are solved theoretically in terms of dimensionless frequencies while assuming a nonlinear Winkler-Pasternak-type foundation. The solution is obtained by means of ultrasonic wave dispersion relations. A parametric work is carried out to check for the effect of the nonlocal scaling parameter, together with the magneto-mechanical loadings, the foundation parameters, the attached mass, boundary conditions and geometries, on the dimensionless frequency of nanotubes. The sensitivity of the mechanical response of nanotubes investigated herein, could be of great interest for design purposes in nano-engineering systems and devices.

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Zhou, Xin, Haifang Cai, Chunwei Hu, Jiao Shi, Zongli Li i Kun Cai. "Analogous Diamondene Nanotube Structure Prediction Based on Molecular Dynamics and First-Principle Calculations". Nanomaterials 10, nr 5 (28.04.2020): 846. http://dx.doi.org/10.3390/nano10050846.

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A concentric twin tube (CTT) can be built by placing a carbon nanotube (CNT) in another identical CNT. Different from diamondene nanotubes, a stable CTT has no inter-shell covalent bond. As a prestressed double-walled nanotube, CTT has a lower structural stability at a finite temperature. According to the molecular dynamics and first-principle calculations, (a) CTTs have three types of relaxed configurations. In a type III CTT, the inner tube buckles to produce a V-shaped cross-section, and the outer tube may be convex or concave. (b) The minimal radii of relaxed zigzag and armchair CTTs with concave outer tubes were found. (c) After relaxation, the circumferences and areas of the two tubes in a type III CTT are different from those of the corresponding ideal CNT. The area change rate (A-CR) and circumference change rate (C-CR) of the outer tube are the first-order Gaussian function of the radius of the ideal CNT (which forms the CTT), and tends to be 73.3% of A-CR or 95.3% of C-CR, respectively. For the inner tube of a CTT, the A-CR is between 29.3% and 37.0%, and the C-CR is close to 95.8%. (d) The temperature slightly influences the findings given above.

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Rybolt, Thomas, i Heir Jordan. "Interactions and Binding Energies in Carbon Nanotube Bundles". Applied Nano 2, nr 2 (10.06.2021): 128–47. http://dx.doi.org/10.3390/applnano2020011.

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On any size scale, it is important to know how strongly structural components are held together. The purpose of this work was to develop a means to estimate the collective binding energy holding together a bundle of aligned carbon nanotubes (CNTs). Carbon nanotubes in isolation and in bundles have unique and useful properties and applications within supramolecular structures and nanotechnology. Equations were derived to represent the total number of pairwise interactions between the CNTs found in various size and shape bundles. The shapes considered included diamond, hexagon, parallelogram, and rectangle. Parameters were used to characterize the size of a bundle for each defined shape. Force field molecular modeling was used to obtain the total bundle binding energies for a number of sample bundles. From the number of interactions per bundle, the binding energy per interaction was determined. This process was repeated for armchair CNTs having a range of length and circumference values. A simple equation described the interaction energy based on the length and circumference of the component armchair type nanotubes. When combined with the bundle shape and size parameters, the total bundle binding energy could be found. Comparison with whole bundle molecular mechanics calculations showed our formula-based approach to be effective.

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Glukhova O. E., Slepchenkov M. M. i Kolesnichenko P. A. "Tunneling current between structural elements of thin graphene/nanotube films". Physics of the Solid State 64, nr 14 (2022): 2450. http://dx.doi.org/10.21883/pss.2022.14.54349.180.

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Based on the constructed atomistic models of graphene/nanotube films with different numbers of nanotubes in supercells, we carried out in silico studies of the regularities of the nonuniform density distribution, which determine the presence of an island structure in such films. As a result of quantum molecular dynamics modeling, it is found that thin tubes of subnanometer diameter are enveloped in graphene sheets, which makes them energetically stable and stable. We also studied tunneling contacts between individual film fragments that are not covalently bound, in particular, between graphene sheets with different topologies of contacting zigzag and armchair edges, depending on the distance between them, and between tubes of different chiralities, including (6,3), (4,4), (6,5), (12,6) and (16,0). It is found that the tunnel contacts of tubes with a semiconductor type of conductivity are characterized by the presence of voltage intervals with a negative differential resistance in the I-V characteristic. Such voltage intervals are not observed at all for tubes with a metallic character of conductivity. The new knowledge obtained is important for assessing the electrical conductivity of such films, two-thirds of which are semiconductor tubes. Keywords: graphene, nanotubes, tunnel contacts.

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Slepchenkov, Michael M., Pavel V. Barkov i Olga E. Glukhova. "Electronic and Electrical Properties of Island-Type Hybrid Structures Based on Bi-Layer Graphene and Chiral Nanotubes: Predictive Analysis by Quantum Simulation Methods". Coatings 13, nr 5 (22.05.2023): 966. http://dx.doi.org/10.3390/coatings13050966.

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Hybrid structures based on graphene and carbon nanotubes (CNTs) are one of the most relevant modern nanomaterials for applications in various fields, including electronics. The variety of topological architectures of graphene/CNT hybrids requires a preliminary study of their physical properties by in silico methods. This paper is devoted to the study of the electronic and electrical properties of graphene/CNT hybrid 2D structures with an island topology using the self-consistent charge density functional-based tight-binding (SCC-DFTB) formalism and the Landauer–Buttiker formalism. The island-type topology is understood as the atomic configuration of a graphene/CNT hybrid film, in which the structural fragments of graphene and nanotubes form “islands” (regions of the atomic structure) with an increased density of carbon atoms. The island-type graphene/CNT hybrid structures are formed by AB-stacked bilayer graphene and (6,3)/(12,8) chiral single-walled carbon nanotubes (SWCNT). The bilayer graphene is located above the nanotube perpendicular to its axis. Based on the binding energy calculations, it is found that the atomistic models of the studied graphene/SWCNT hybrid structures are thermodynamically stable. The peculiarities of the band structure of graphene/SWCNT (6,3) and graphene/SWCNT (12,8) hybrid structures are analyzed. It is shown that the electronic properties of graphene/SWCNT hybrid structures are sensitive to the orientation and size of the graphene layers with respect to the nanotube surface. It is found that an energy gap of ~0.1 eV opens in the band structure of only the graphene/SWCNT (6,3) hybrid structure, in which the graphene layers of the same length are arranged horizontally above the nanotube surface. We revealed the electrical conductivity anisotropy for all considered atomistic models of the graphene/SWCNT (12,8) hybrid structure when bilayer graphene sheets with different sizes along the zigzag and armchair directions are located at an angle with respect to the nanotube surface. The obtained knowledge is important to evaluate the prospects for the potential application of the considered atomic configurations of graphene/SWCNT hybrid structures with island-type topology as connecting conductors and electrodes in electronic devices.

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Yengejeh, Sadegh Imani, Andreas Öchsner, Seyedeh Alieh Kazemi i Maksym Rybachuk. "Numerical Analysis of the Structural Stability of Ideal (Defect-Free) and Structurally and Morphologically Degenerated Homogeneous, Linearly- and Angle-Adjoined Nanotubes and Cylindrical Fullerenes Under Axial Loading Using Finite Element Method". International Journal of Applied Mechanics 10, nr 09 (listopad 2018): 1850100. http://dx.doi.org/10.1142/s1758825118501004.

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We report on the structural stability of ideal (defect-free) and structurally and morphologically degenerate carbon nanotubes and nanotube junction systems under axial loading based on the finite element method. We estimated the values for critical buckling load for uncapped and capped single-walled carbon nanotubes (SWCNTs) and linear and angle-adjoined SWCNT heterojunctions in ideal and structurally degenerate systems containing single-, double-, triple-, pinhole- and pentagon–heptagon (i.e., 5–7) structural defects and also containing a substitutional nitrogen (N) atom inclusion under compressive loading. Absolute atomic vacancy (defect) concentration in studied SWCNTs models was assumed to be nil for ideal systems, and was up to 3.0 at.% for structurally and morphologically degenerate systems. It was found that all types of structural defects and the morphological N-defect had reduced the load carrying capacity and mechanical strength in all SWCNT systems studied. The SWCNT models containing physically large vacant sites, such as triple- and pinhole-defects, displayed significantly lower critical load values compared to the systems that contained only a single-, double- or triple-vacancies. In addition, we found that capped SWCNTs performed marginally better in critical load carrying capacity compared to uncapped SWCNT systems. Furthermore, majority of the investigated structures displayed reduced load in SWCNTs with narrower tube widths, proportional to the size and the type of the defect investigated. The effects of chirality, such as zigzag- versus armchair-type, on the structural stability of the investigated SWCNT models were also investigated.

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Глухова, О. Е., М. М. Слепченков i П. А. Колесниченко. "Туннельный ток между структурными элементами тонких графен/нанотрубных пленок". Физика твердого тела 63, nr 12 (2021): 2198. http://dx.doi.org/10.21883/ftt.2021.12.51684.180.

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Based on the constructed atomistic models of graphene/nanotube films with different numbers of nanotubes in supercells, we carried out in silico studies of the regularities of the nonuniform density distribution, which determine the presence of an island structure in such films. As a result of quantum molecular dynamics modeling, it is found that thin tubes of subnanometer diameter are enveloped in graphene sheets, which makes them energetically stable and stable. We also studied tunneling contacts between individual film fragments that are not covalently bound, in particular, between graphene sheets with different topologies of contacting zigzag and armchair edges, depending on the distance between them, and between tubes of different chiralities, including (6,3), (4,4), (6,5), (12,6) and (16,0). It is found that the tunnel contacts of tubes with a semiconductor type of conductivity are characterized by the presence of voltage intervals with a negative differential resistance in the I – V characteristic. Such voltage intervals are not observed at all for tubes with a metallic character of conductivity. The new knowledge obtained is important for assessing the electrical conductivity of such films, two-thirds of which are semiconductor tubes.

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Mohammadi, Mohsen Doust, i Hewa Y. Abdullah. "DFT Study for Adsorbing of Bromine Monochloride onto BNNT (5,5), BNNT (7,0), BC₂NNT (5,5), and BC₂NNT (7,0)". Journal of Computational Biophysics and Chemistry 20, nr 08 (24.11.2021): 765–83. http://dx.doi.org/10.1142/s2737416521500472.

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The study of intermolecular interactions is of great importance. This study attempted to quantitatively examine the interactions between bromine monochloride (BrCl) with pristine boron nitride nanotube (BNNT) armchair (5,5) and zigzag (7,0) as well as armchair (5,5) BC2NNT and zigzag (7,0) BC2NNT in vacuum. Quantum mechanical studies of such systems are possible in the density functional theory (DFT) framework. For this purpose, various functionals, such as B3LYP-D3, [Formula: see text]B97XD, and M062X, have been used. One of the most suitable basis functionals for the systems studied in this research is 6-311G (d), which has been used in both optimization calculations and calculations related to wave function analyses. The main part of this work is the study of various analyses that reveal the nature of the intermolecular interactions between the two components introduced above. The results of conceptual DFT, natural bond orbital, non-covalent interactions, and quantum theory of atoms in molecules (QTAIM) were consistent and in favor of physical adsorption in all systems. Gallium had more adsorption energy than other dopants. The HOMO–LUMO energy gaps were as follows: BNNT (5,5): 10.296, BNNT (7,0): 9.015, BC2NNT (5,5): 7.022, and BC2NNT (7,0): 5.979[Formula: see text]eV at B3LYP-D3/6-311G (d) model chemistry. The strongest interaction is related to the BC2NNT (7,0)/BrCl cluster: [Formula: see text][Formula: see text]eV. The results of QTAIM and NCI analysis identified the intermolecular interactions of the type of strong van der Waals interaction for these nanotubes. The sensitivity of the adsorption increased when a gas molecule interacted with carbon-doped BNNT, and the change in the frontier orbital gap could be used to design nanosensors to detect BrCl gas.

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Dhawan, Manish, i Raj Chawla. "A computational study on thermo-mechanical characterization of carbon nanotube reinforced natural rubber". MRS Advances 4, nr 20 (2019): 1161–66. http://dx.doi.org/10.1557/adv.2018.680.

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ABSTRACTA computational study based on molecular dynamics simulation technique has been used to predict the mechanical and thermal behavior of carbon nanotube (CNT) reinforced natural rubber (NR) composites. A single-walled 5,5 armchair type CNT has been used for this purpose. In this study, a comparison has been made between pristine and functionalized CNTs. The functionalization groups used in this study were carboxylic (COOH), ester (COOCH3) and hydroxyl (OH). The studies show the improvement in elastic properties of developed composites in the presence of functionalization group. In addition, the effect of volume fraction and 1-25% addition of functionalization group has been studied. The obtained simulation results show the better load-transfer capacity in developed polymer system and improved elastic modulus. Thermal properties of developed composite systems were studied by non-equilibrium molecular dynamics method (NEMD). The addition of functionalized CNTs shows enhanced mechanical and thermal properties.

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Zhao, Yipeng, Huamin Hu i Gang Ouyang. "Optimizing the photovoltaic effect in one-dimensional single-wall carbon nanotube @ MoS₂ van der Waals heteronanotubes". Journal of Applied Physics 132, nr 23 (21.12.2022): 234304. http://dx.doi.org/10.1063/5.0124128.

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One-dimensional single-wall carbon nanotube (1D-SWCNT)@MoS2 van der Waals (vdW) heteronanotubes (HNTs) have inherited extensive attention due to their fascinating properties and increasing mature methods. However, the curvature and chirality dependence of photovoltaic properties in such kind of 1D systems remain unclear. In our work, we explore the electronic and photoelectric properties of 1D-SWCNT@MoS2 vdW HNTs based on the atomic-bond-relaxation approach and the modified detailed balance principle by quantization of band offset and carrier transport behaviors. We find that the optimized power conversion efficiency (PCE) of zigzag-SWCNT@ zigzag-MoS2 HNTs is ∼5.3% at the diameter of 3.1 nm, while that of zigzag-SWCNT@ armchair-MoS2 HNTs is ∼4.9% at 3.3 nm. Moreover, the PCE can be enhanced further by intercalating h-BN layers at the interface of 1D-vdW HNTs. Our results suggest that 1D-SWCNT@MoS2 HNTs can be served as promising building blocks for the new type of photovoltaic devices.

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Wu, Jianbao, Liyuan Jiang, Xiaoyi Li i Zhixiang Yin. "C2O Nanotubes with Negative Strain Energies and Improvements of Thermoelectric Properties via N-Doping Predicted from First-Principle Calculations". Crystals 13, nr 7 (13.07.2023): 1097. http://dx.doi.org/10.3390/cryst13071097.

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In this study, the geometric structure, strain energy, and electronic properties of armchair C2O nanotubes (A_C2ONTs(n,n)) and zigzag C2O nanotubes (Z_C2ONTs(n,0)) are studied in detail. The results show that these nanotubes behave as special shapes; the section of Z_C2ONTs(n,0) along the axial direction is an n-edge type, and the section tends to be round with an increase in n while the boundary of section along the axial direction for A_C2ONTs(n,n) fluctuates. With an increase in n, the fluctuation disappears gradually, and the section also tends to be round. Compared with C2O nanosheets (g_C2O), C2O nanotubes have similar or even smaller strain energy, when the tube diameter is greater than or equal to 15 Å, the strain energy begins to show a negative value, and the negative value tends to be stable as the pipe diameter increases. Z_C2ONTs start to show negative strain energies from n = 8 and A_C2ONTs from n = 12, indicating their higher stabilities relative to the g_C2O sheets. The calculation of the electronic band structure shows that Z_C2ONTs are an indirect band gap semiconductor, and A_C2ONT is a direct band gap semiconductor. The band gap value of Z_C2ONTs first increases and then stabilizes with the diameters of the nanotubes, and the band gap value of A_C2ONTs decreases with the increase in the nanotubes and tends to the band gap value of the g_C2O sheet. In addition, the electronic properties and thermoelectric properties of C2ONTs(n=4,6,8) before and after N-doping were also studied. We found that N-doping changed the electronic and thermoelectric properties of C2ONTs. It reduced the nanotube band gap value and significantly improved the thermoelectric figures of merit of Z_C2ONTs(n=4,6,8) and A_C2ONT(4,4), which comprised an effective strategy to improve the thermoelectric figure of merit of nanotubes. The results showed that the C2ONTs had potential as thermoelectric materials after N-doping, which provided important guidance for designing low-dimensional g_C2O nanostructures.

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Xiang, Yi, Koji Shimoyama, Keiichi Shirasu i Go Yamamoto. "Machine Learning-Assisted High-Throughput Molecular Dynamics Simulation of High-Mechanical Performance Carbon Nanotube Structure". Nanomaterials 10, nr 12 (9.12.2020): 2459. http://dx.doi.org/10.3390/nano10122459.

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Carbon nanotubes (CNTs) are novel materials with extraordinary mechanical properties. To gain insight on the design of high-mechanical-performance CNT-reinforced composites, the optimal structure of CNTs with high nominal tensile strength was determined in this study, where the nominal values correspond to the cross-sectional area of the entire specimen, including the hollow core. By using machine learning-assisted high-throughput molecular dynamics (HTMD) simulation, the relationship among the following structural parameters/properties was investigated: diameter, number of walls, chirality, and crosslink density. A database, comprising the various tensile test simulation results, was analyzed using a self-organizing map (SOM). It was observed that the influence of crosslink density on the nominal tensile strength tends to gradually decrease from the outside to the inside; generally, the crosslink density between the outermost wall and its adjacent wall is highly significant. In particular, based on our calculation conditions, five-walled, armchair-type CNTs with an outer diameter of 43.39 Å and crosslink densities (between the inner wall and outer wall) of 1.38 ± 1.16%, 1.13 ± 0.69%, 1.54 ± 0.57%, and 1.36 ± 0.35% were believed to be the optimal structure, with the nominal tensile strength and nominal Young’s modulus reaching approximately 58–64 GPa and 677–698 GPa.

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Sergeeva, E. S. "Dependence of the Elastic Properties of a Single-Walled Carbon Nanotube on its Chirality". Solid State Phenomena 284 (październik 2018): 20–24. http://dx.doi.org/10.4028/www.scientific.net/ssp.284.20.

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Currently, composite materials composed of a matrix and reinforcing components are widely used as a structural material for various engineering devices designed to operate under extreme loads of different types. By modifying a composite with structure-sensitive inclusions, such as a single-wall carbon nanotube, the mechanical properties, especially elastic characteristics, of the resulting material can be significantly improved. The results of investigation of a single-walled carbon nanotubes chirality influence on its elastic properties are presented. Various configurations of nanotubes, such as zigzag and armchair are considered. The dependences of the nanotube bulk modulus and shear modulus of its diameter are shown.

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Huang, Qingqun, Ali Ahmad, Muhammad Kamran Jamil, Ricai Luo i Muhammad Azeem. "Comparative study of vertex-edge based indices for semi-capped carbon nanotubes". Mathematical Biosciences and Engineering 19, nr 12 (2022): 12303–15. http://dx.doi.org/10.3934/mbe.2022573.

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<abstract><p>Manufacturing relatively inexpensive items in every area of engineering and science is the major focus of exploration resultant the world's contemporary economic setback. Making small-sized items that are inexpensive and lightweight while providing high quality is critical in today's and tomorrow's worlds. Nanotechnology has a significant role to play in this situation. Nano-objects or, in general, nanomaterials are especially preferred; nanotubes, especially those comprised of carbon, are one of the most popular types of nanostructures, and they are applied in a variety of chemical, biological and technical applications. This notion prompted us to investigate their many physical and chemical characteristics. We utilized topological descriptors to evaluate diverse nanotube structures such as armchair carbon and semi-capped nanotubes by using vertex-edge based indices to characterize distinct chemical structures via numerical quantitative analysis. Furthermore, we examined uncapped and semi-capped armchair carbon nanotubes and achieved adequate comparative findings.</p></abstract>

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24

Bobenko, Nadezhda, Valeriy Egorushkin i Alexander Ponomarev. "Hysteresis in Heat Capacity of MWCNTs Caused by Interface Behavior". Nanomaterials 12, nr 18 (10.09.2022): 3139. http://dx.doi.org/10.3390/nano12183139.

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The paper is concerned with the study of structural disorder as well as the emergence and causes of heat capacity hysteresis in multiwall carbon nanotubes. The investigation methods are X-ray diffraction analysis, Raman spectroscopy, transmission electron microscopy, and calorimetric tests: thermogravimetric analysis, differential scanning calorimetry, and the thermal relaxation method for heat capacity hysteresis. Multiwall carbon nanotubes are shown to be composed of one or several types of zigzag–armchair domains. The domain structure of nanotube samples is responsible for the generation of uniaxial elastic microstrains and viscoelastic bending strains at domain interfaces. The thermomechanical behavior of interfaces is the chief cause of temperature hysteresis of heat capacity. The number of hystereses corresponds to the number of domain types in the structure, and values of hysteresis are determined by the crystallite size, thermal conductivity, and normal temperature distribution of strain. The found mechanism of heat capacity hysteresis can be helpful in preventing jumps in thermal properties and managing thermal memory in multiwall carbon nanotubes.

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25

Palacios, Jorge A., i Rajamohan Ganesan. "Dynamic response of single-walled carbon nanotubes based on various shell theories". Journal of Reinforced Plastics and Composites 38, nr 9 (15.01.2019): 413–25. http://dx.doi.org/10.1177/0731684418824997.

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Carbon nanotubes are used in several engineering applications because of their superior mechanical properties. Scientific works still need to be carried out, especially on their dynamic response. These studies mainly focus on modal analysis, considering zigzag and armchair nanotubes, and sometimes, varying chirality. However, these works do not present any results on the steady-state responses. Therefore, the objective of this paper is to perform different studies, in terms of the stiffness response, modal analysis and steady-state response of single-walled carbon nanotubes by using a 3D finite-element model of the single-walled carbon nanotube, under different types of boundary conditions, to provide more results in this field. The single-walled carbon nanotube is modeled as a space frame structure by using the Morse potential and as a thin shell model based on various shell theories. A static analysis is performed to compare the stress–strain behavior between the Morse potential and the thin shell model. A parametric study on chirality effects and aspect ratio is also conducted to determine which shell theory is more suitable to model the mechanical behavior of single-walled carbon nanotubes. Finally, the analysis of harmonic response is conducted to describe the steady-state response between both the models.

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26

MAJZOOBI, G. H., J. PAYANDEHPEYMAN i Z. BOLBOLI NOJINI. "AN INVESTIGATION INTO THE TORSIONAL BUCKLING OF CARBON NANOTUBES USING MOLECULAR AND STRUCTURAL MECHANICS". International Journal of Nanoscience 10, nr 04n05 (sierpień 2011): 989–93. http://dx.doi.org/10.1142/s0219581x11008666.

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In this work, the critical twist angles of two types of CNTs, zigzag and armchair of different lengths are determined using molecular and structural mechanics. The results show that the torsional buckling modes predicted by the two methods are the same. It is also shown that critical twist angle decreases as CNTs length increases. Structural mechanics underpredicts the critical angle for both armchair and zigzag nonotubes. It is also shown that the critical angle for armchair nanotubes is higher than that for zigzag nanotubes.

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27

Matsunaga, Yasushi, Tomokazu Kato i Tadatsugu Hatori. "Selective production of armchair-type carbon nanotubes". Journal of Applied Physics 95, nr 12 (15.06.2004): 8149–54. http://dx.doi.org/10.1063/1.1713027.

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Fülep, Dávid, Ibolya Zsoldos i István László. "Position Sensitivity Study in Molecular Dynamics Simulations of Self-Organized Development of 3D Nanostructures". Materials Science Forum 885 (luty 2017): 216–21. http://dx.doi.org/10.4028/www.scientific.net/msf.885.216.

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The sensitivity of defect free fusion of straight carbon nanotubes from graphene nanoribbons to the position of the nanoribbon edge positions has been investigated. A basic difference between the behavior of armchair and zigzag type nanoribbons was observed. When placing armchair type graphene nanoribbons above each other identical, fitting positions are obtained automatically. Zigzag type graphene nanoribbons, however, must not be placed above each other in identical positions. From the viewpoint of defect-free fusion, according to the MD simulations symmetric on nearly symmetric positions of the ribbon edges are favorable.

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29

PANCHAL, MITESH B., S. H. UPADHYAY i S. P. HARSHA. "AN EFFICIENT FINITE ELEMENT MODEL FOR ANALYSIS OF SINGLE WALLED BORON NITRIDE NANOTUBE-BASED RESONANT NANOMECHANICAL SENSORS". Nano 08, nr 01 (luty 2013): 1350011. http://dx.doi.org/10.1142/s1793292013500112.

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In this paper, the dynamics analysis of single walled boron nitride nanotubes (SWBNNT) as a resonant nanomechanical sensor by using the finite element method has been reported. Molecular structural mechanics-based finite element model (FEM) has been developed by using three-dimensional elastic beams and point masses, such that the proximity of the model to the actual atomic structure of nanotube is significantly retained. Different types of armchair layups of SWBNNTs are considered with cantilevered and bridged end constraints. By implementing the finite element simulation approach, the resonant frequency shift-based mass sensitivity analysis is performed for both types of end constraints for considered armchair form of the SWBNNTs with different aspect ratios. For both types of end constraint, continuum mechanics-based analytical formulations, considering effective wall thickness of nanotubes are used to validate the present FEM-based simulation approach. The intermediate landing position of the added mass is analyzed, considering variations in resonant frequency shifts of the different fundamental modes of vibrations for both types of end constraints. The FEM-based simulation results for both types of end constraints found in good agreement with the continuum mechanics-based analytical results for the aspect ratio of range of 9–15. The mass sensitivity limit of 10-1 zg is achieved for SWBNNT-based resonant nanomechanical sensors. The resonant frequency shift for higher-order fundamental vibrational modes become stable as the attached mass moves away from the fixed ends for particular magnitude of attached mass. The present finite element-based approach is found to be effectual in terms of dealing different atomic structures, boundary conditions and consideration of added mass to analyze the dynamic behavior of the SWBNNT-based resonant nanomechanical sensors.

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30

Shunaev V. V., Chetverikov A.P. i Glukhova O. E. "Propagation of supersonic soliton in carbon nanotubes of armchair type". Technical Physics 68, nr 4 (2023): 427. http://dx.doi.org/10.21883/tp.2023.04.55932.286-22.

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The propagation of a localized ring nonlinear wave in carbon nanotubes (CNTs) of armchair type has been explored using the MD/DFTB method. It is unambiguously shown that the considered localized waves are soliton-type. Herewith, the higher a velocity of an initial perturbation, the higher a steady-state velocity of the considered soliton. It is established that at a high initial excitation energy in a time period of 0.1-0.2 ps the soliton moves at the speed in the range of 245-270 Angstrem/ps, which is approximately in 1.22-1.35 times higher than the speed of sound in CNTs (200 Angstrem/ps). It is shown that the soliton velocity practically does not change with increasing CNT radius Keywords: molecular dynamics, carbon nanotubes, soliton, supersonic wave.

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31

Costa Paura, Edson Nunes, Wiliam F. da Cunha, Luiz Fernando Roncaratti, João B. L. Martins, Geraldo M. e Silva i Ricardo Gargano. "CO2 adsorption on single-walled boron nitride nanotubes containing vacancy defects". RSC Advances 5, nr 35 (2015): 27412–20. http://dx.doi.org/10.1039/c4ra17336h.

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32

Sünel, N., E. Rızaoğlu, K. Harigaya i O. Özsoy. "Bond distortions in armchair type single wall carbon nanotubes". Physics Letters A 338, nr 3-5 (maj 2005): 366–72. http://dx.doi.org/10.1016/j.physleta.2005.02.033.

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33

Herrera-Carbajal, Alejandro, Ventura Rodríguez-Lugo, Juan Hernández-Ávila i Ariadna Sánchez-Castillo. "A theoretical study on the electronic, structural and optical properties of armchair, zigzag and chiral silicon–germanium nanotubes". Physical Chemistry Chemical Physics 23, nr 23 (2021): 13075–86. http://dx.doi.org/10.1039/d1cp00519g.

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Infinite size silicon–germanium alloy nanotubes of several types, armchair, zigzag and chiral, are studied by theoretical analysis based on density functional theory as implemented in the SIESTA code.

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34

Fan, Cheng Wen, Jhih Hua Huang, Chyan Bin Hwu i Yu Yang Liu. "Mechanical Properties of Single-Walled Carbon Nanotubes - A Finite Element Approach". Advanced Materials Research 33-37 (marzec 2008): 937–42. http://dx.doi.org/10.4028/www.scientific.net/amr.33-37.937.

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In this paper, the mechanical properties, such as the axial and radial Young’s moduli, shear moduli, buckling loads and natural frequencies, of single-walled carbon nanotubes, are estimated by a finite element approach. Each carbon nanotube is simulated as a frame-like structure and the primary bonds between two nearest-neighboring atoms are treated as isotropic beam members with a uniform circular cross-section. In the modeling work, the BEAM4 element in commercial code ANSYS is selected to simulate the carbon bonds and the atoms are nodes. As to the input parameters of the BEAM4 element, they are determined via the concept of energy equivalence between molecular dynamics and structural mechanics, and represented in terms of the force constants of the carbon bonds found in molecular mechanics. Based on this modeling concept, finite element models of both armchair and zigzag types of carbon nanotubes with different sizes are established and the mechanical properties of these tubes are then effectively predicted. Most of the computed results which can be compared with existing results show good agreement. Moreover, the effects of tube diameter, length etc., on the mechanical properties are also investigated.

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35

LU, SHENG, i CHONGDU CHO. "THE STUDY OF INSCRIBED SURFACE OF ARMCHAIR CARBON NANOTUBES". Modern Physics Letters B 24, nr 19 (30.07.2010): 2021–29. http://dx.doi.org/10.1142/s0217984910024419.

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It is natural to treat the monolayer crystalline film as the surface fixed by the positions of atoms. However, this type surface is not well-suited to the monolayer crystalline film. It has been discovered that the mechanical properties of a monolayer crystalline film can be described exquisitely by its inscribed surface. Depending on this inscribed surface of armchair carbon nanotubes, the present study shows the reason why CNTs cannot be simply considered as a thin shell with constant thickness. Application of the present model to armchair CNTs predicts that the ranges of Young's modulus and effective thickness are respectively from 2.407 to 3.209 TPa and from 0.082 to 0.073 nm, which are in good agreement with previous theoretical studies and experimental observations.

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36

TALUKDAR, KEKA, i APURBA KRISHNA MITRA. "THE ROLE OF POTENTIAL FUNCTIONS IN THE MECHANICAL BEHAVIOR OF THE SINGLE WALL CARBON NANOTUBES". International Journal of Nanoscience 11, nr 03 (czerwiec 2012): 1240009. http://dx.doi.org/10.1142/s0219581x12400091.

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Carbon nanotubes have been identified as the promising agents in reinforcing composite materials to achieve desired mechanical properties. In this study, three different types of single wall carbon nanotubes (SWCNTs) are subjected to molecular dynamics simulation to investigate their mechanical properties taking different interatomic potential functions. With unmodified Brenner's 2nd generation potential, a brittle fracture for all the SWCNTs is observed. But in tight-binding approach, the chiral and armchair SWCNTs exhibit somewhat extended plastic flow region before failure. With unmodified Brenner's potential, high tensile strength and ductility are observed for the armchair and chiral tubes. Y value of these two tubes is less than 1 TPa but more than 1 TPa for a zigzag tube. Much decrease of tensile strength and strain are noticed when we apply smoothing of the Brenner's potential at cut-off region. Failure stresses are dropped to much lower values for the three tubes. Ductility of the armchair and chiral tubes are also affected considerably by the choice of potential. Applying smoothing in the cut-off region to conserve the energy, the results show better agreement with the experimental findings.

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37

Shailesh, Sarvesh Kumar, B. Tiwari i K. Yadav. "Green Synthesis, Texture, Electron Diffraction, Thermal and Optical Properties of Cobalt Doped Arginine Carbon Nanotubes". Asian Journal of Chemistry 33, nr 5 (2021): 1120–24. http://dx.doi.org/10.14233/ajchem.2021.22684.

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In this work, a simple and viable method of green synthesis of multi-walled cobalt doped arginine carbon nanotubes (CNT’s) by chemical precipitation method using arginine amino acid is reported. The atomic force microscopy confirmed that metal ions present in a branched fashion on the surface of Co-doped arginine CNT’s and the obtained particle with diameter 20 nm well dispersed on the carbon nanotubes. The TEM analysis indicates the interlayer separation between the two adjacent carbon walls is estimated to be about 0.34 nm. The electron diffraction patterns indicate that the tube has nearly identical chirality for all of the concentric graphitic layers, as a zigzag-type MWCNT. The SEM analysis predicted tube like morphology and strain is existed on the surface of the CNTs. The Raman spectra confirmed the armchair (n = 8 to 11) multi-walled nanotubes with this chirality are assigned as a semiconducting type of nanotubes. The thermal property was studied by thermogravimetric analysis, differential thermal analysis and predicted the 27.81 % purity in CNTs.

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38

Zeighampour, Hamid, Yaghoub Tadi Beni i Yaser Kiani. "Electric Field Effects on Buckling Analysis of Boron–Nitride Nanotubes Using Surface Elasticity Theory". International Journal of Structural Stability and Dynamics 20, nr 12 (10.10.2020): 2050137. http://dx.doi.org/10.1142/s0219455420501370.

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In this paper, the axial buckling of boron nitride nanotubes (BNNTs) is investigated by considering the effects of surface and electric field. To achieve this purpose, the surface elasticity theory is exploited and the results are compared with the molecular dynamic simulation in order to validate the accuracy of the applied theory. In the molecular dynamics simulation, the potential between boron and nitride atoms is considered as Tersoff type. The Timoshenko beam theory is adopted to model BNNT. Moreover, two types of zigzag and armchair BNNTs are considered. In this study, the effects of surface, electric field, length, and thickness of BNNT on the critical buckling load are investigated. According to the results, the critical load of zigzag BNNT depends on the electric field. However, the electric field would not affect the critical load of the armchair BNNT. It should be noted that the surface residual tension and surface Lamé’s constants of BNNT have considerable impact on the critical load of BNNT. For lower values of electric field and smaller dimensions of BNNT, the critical load would be more dependent on the surface effect regarding the results. Furthermore, as an efficient non-classical continuum mechanic approach, the surface elasticity theory can fill the potential gap between the classical continuum mechanic and molecular dynamics simulation.

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39

Lei, Xiaowen, Toshiaki Natsuki, Jinxing Shi i Qing-Qing Ni. "Analysis of Carbon Nanotubes on the Mechanical Properties at Atomic Scale". Journal of Nanomaterials 2011 (2011): 1–10. http://dx.doi.org/10.1155/2011/805313.

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This paper aims at developing a mathematic model to characterize the mechanical properties of single-walled carbon nanotubes (SWCNTs). The carbon-carbon (C–C) bonds between two adjacent atoms are modeled as Euler beams. According to the relationship of Tersoff-Brenner force theory and potential energy acting on C–C bonds, material constants of beam element are determined at the atomic scale. Based on the elastic deformation energy and mechanical equilibrium of a unit in graphite sheet, simply form ED equations of calculating Young's modulus of armchair and zigzag graphite sheets are derived. Following with the geometrical relationship of SWCNTs in cylindrical coordinates and the structure mechanics approach, Young's modulus and Poisson's ratio of armchair and zigzag SWCNTs are also investigated. The results show that the approach to research mechanical properties of SWCNTs is a concise and valid method. We consider that it will be useful technique to progress on this type of investigation.

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40

LU, HONGXIA, JIANBAO WU, JIZHEN WANG, SHAOCONG SHI i WEIYI ZHANG. "THE BAND-GAP AND TRUE BAND-GAP IN NOMINALLY METALLIC CARBON NANOTUBES: THE TIGHT-BINDING STUDY ON CORRUGATION EFFECT". International Journal of Modern Physics B 28, nr 08 (24.02.2014): 1450018. http://dx.doi.org/10.1142/s0217979214500180.

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In this paper, the band-gap and true band-gap are analyzed for the corrugated structures of various types of single wall carbon nanotubes (SWCNTs) within the tight binding approximation. We show that corrugation, combined with curvature effect, yields naturally the true small band-gap in all SWCNTs with small radius. The more stable corrugated structures of SWCNTs are backed by the abinitio total energy calculations for nominally metallic armchair SWCNTs.

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41

Ghavamian, Ali, i Andreas Öchsner. "Numerical Modeling of the Eigenmodes and Eigenfrequencies of Carbon Nanotubes under the Influence of Defects". Journal of Nano Research 21 (grudzień 2012): 159–64. http://dx.doi.org/10.4028/www.scientific.net/jnanor.21.159.

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Two configurations of perfect single walled carbon nanotubes (armchair and zigzag) were simulated based on the finite element method. Then, three most likely defects (Si-doping, carbon vacancy and perturbation) were introduced to the models to represent defective forms of single walled carbon nanotubes (SWCNTs). Finally, the vibrational properties of perfect and defective carbon nanotubes were evaluated and compared. The results showed that SWCNTs have a natural frequency with a rather high value between 18.69 and 24.01 GHz. In the consideration of the natural frequency of the defective SWCNTs, it was also observed that the existence of any type of defects or irregularities leads to a lower value of natural frequency and vibrational stability. Simple mathematical relations which express the change in natural frequency versus the percentage of the defect were also presented. This can be very useful to realistically estimate the influence of defects of different amounts on the vibrational behavior of carbon nanotubes.

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42

Wanaguru, Prabath, i Asok K. Ray. "Unusual Bonding Characteristics in a New Type of Single Walled Armchair SiGe Nanotubes". Journal of Computational and Theoretical Nanoscience 10, nr 4 (1.04.2013): 859–66. http://dx.doi.org/10.1166/jctn.2013.2782.

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43

Zhang, Kai, Erhu Zhang, Huawei Chen i Shengli Zhang. "Spin–curvature interaction from curved Dirac equation: Application to single-wall carbon nanotubes". International Journal of Modern Physics B 31, nr 15 (14.03.2017): 1750120. http://dx.doi.org/10.1142/s021797921750120x.

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The spin–curvature interaction (SCI) and its effects are investigated based on curved Dirac equation. Through the low-energy approximation of curved Dirac equation, the Hamiltonian of SCI is obtained and depends on the geometry and spinor structure of manifold. We find that the curvature can be considered as field strength and couples with spin through Zeeman-like term. Then, we use dimension reduction to derive the local Hamiltonian of SCI for cylinder surface, which implies that the effective Hamiltonian of single-wall carbon nanotubes results from the geometry and spinor structure of lattice and includes two types of interactions: one does not break any symmetries of the lattice and only shifts the Dirac points for all nanotubes, while the other one does and opens the gaps except for armchair nanotubes. At last, analytical expressions of the band gaps and the shifts of their positions induced by curvature are given for metallic nanotubes. These results agree well with experiments and can be verified experimentally.

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44

D'yachkov, Pavel N., i Evgeny P. D'yachkov. "Rashba spin–orbit interaction effect in twisted silicon nanotubes for chiral spintronics". Applied Physics Letters 120, nr 17 (25.04.2022): 173101. http://dx.doi.org/10.1063/5.0086902.

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Using a relativistic symmetrized linear augmented cylindrical wave method, we investigated a formation of spin minigaps due to a torsion strain of the nonchiral hexagonal and gear-like armchair ( n, n) and zigzag ( n, 0) silicon nanotubes (SiNTs). In the absence of mechanical twisting, the hexagonal ( n, n) SiNTs have an inversion symmetry and metallic band structures with the spin-degenerate states at the Fermi region. The torsion deformation of hexagonal armchair SiNT breaks the inversion symmetry, transforming it into the chiral system with the right or left screw axis. Due to the combined effect of spin–orbit coupling and low-symmetry perturbation, the degeneration of levels is completely removed and the α and β type bands are formed. The torsion deformation works like a switch, the opposite twisting directions result in the opposite chirality of tubules and induce the opposite spin currents due to Rashba effect. Even in the ideal non-twisted gear-like SiNTs, there is no inversion symmetry. Such tubules have semiconductor band structures with the spin–orbit splittings of the valence and conduction bands. Twisting causes an increase in the antisymmetric component of the potential leading to a monotonic increase in the spin gaps.

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45

Шунаев, В. В., А. П. Четвериков i О. Е. Глуховa. "Распространение сверхзвукового солитона в углеродных нанотрубках типа кресло". Журнал технической физики 93, nr 4 (2023): 458. http://dx.doi.org/10.21883/jtf.2023.04.55032.286-22.

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The propagation of a localized ring nonlinear wave in carbon nanotubes (CNTs) of armchair type has been explored using the MD/DFTB method. It is unambiguously shown that the considered localized waves are soliton-type. Herewith, the higher a velocity of an initial perturbation, the higher a steady-state velocity of the considered soliton. It is established that at a high initial excitation energy in a time period of 0.1-0.2 ps the soliton moves at the speed in the range of 245-270 Å/ps, which is approximately in 1.22-1.35 times higher than the speed of sound in CNTs (200 Å/ps). It is shown that the soliton velocity practically does not change with increasing CNT radius

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46

Sang, Yuan, Chuanhong Jin, Muhammed Habib i Li Song. "Confined Growth of Carbon Nanotubes in Nanocutting Channel on Highly Oriented Pyrolytic Graphite". Nano 13, nr 06 (czerwiec 2018): 1850071. http://dx.doi.org/10.1142/s1793292018500716.

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Graphite surface can be etched by metal particles because of the catalytic hydrogenation, resulting in unique etching channels along crystallographic high-symmetry directions that provide new possibilities for confinement applications. Herein, we demonstrate a confined growth carbon nanotubes (CNT) inside nanocutting channels on the surface of highly oriented pyrolytic graphite (HOPG). In particular, nickel (Ni) nanoparticles were used as catalytic knife to cut HPOG for creating channels with both zig-zag and armchair graphene edge types. Subsequently, multiwall CNTs were grown along the edge inside channels by reacting Ni nanoparticles catalyzing. It was found that the CNTs inside channels could be grown together along same orientation instead of aggregation, which may bring out a new idea on the controllable synthesis of carbon nanotubes.

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47

Narita, Ichihito, i Takeo Oku. "Atomic structure of boron nitride nanotubes with an armchair-type structure studied by HREM". Solid State Communications 129, nr 7 (luty 2004): 415–19. http://dx.doi.org/10.1016/j.ssc.2003.11.027.

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48

Wang, Yan Li, Ke He Su i Xin Wang. "A Density Functional Theory Study on the Ultra Long Single Walled Armchair (3, 3) (Bn)_Xc_y Nanotubes". Advanced Materials Research 463-464 (luty 2012): 1435–39. http://dx.doi.org/10.4028/www.scientific.net/amr.463-464.1435.

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The single walled armchair (3,3) (BN)xCy nanotubes with different ratios of B, C and N atoms were studied with density functional theory of B3LYP/3-21G(d) combined with the periodic boundary conditions in simulating the ultra long tube model. Different types of twelve models were examined and the diameter, energy, energy gaps and the band structures were obtained. The energy gaps were within 0.203eV to 2.620eV showing semiconductor conductivity. Results show that the energy gap and the band structure depend on both the atom ratio and arrangement.

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49

Umeno, Yoshitaka, Atsushi Kubo, Chutian Wang i Hiroyuki Shima. "Diameter-Change-Induced Transition in Buckling Modes of Defective Zigzag Carbon Nanotubes". Nanomaterials 12, nr 15 (29.07.2022): 2617. http://dx.doi.org/10.3390/nano12152617.

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In general, the insertion of Stone-Wales (SW) defects into single-walled carbon nanotubes (SWNTs) reduces the buckling resistance of SWNTs under axial compression. The magnitude of reduction is more noticeable in zigzag-type SWNTs than armchair- or chiral-type SWNTs; however, the relation between the magnitude of reduction and aspect ratio of the zigzag SWNTs remains unclear. This study conducted molecular dynamics (MD) simulation to unveil the buckling performance of zigzag SWNTs exhibiting SW defects with various tube diameter. The dependencies of energetically favorable buckling modes and the SW-defect induced reduction in the critical buckling point on the tube diameter were investigated in a systematic manner. In particular, an approximate expression for the critical buckling force as a function of the tube diameter was formulated based on the MD simulation data.

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50

Dumele, Oliver, i Niklas Grabicki. "Confining the Inner Space of Strained Carbon Nanorings". Synlett 33, nr 01 (15.11.2021): 1–7. http://dx.doi.org/10.1055/s-0040-1719853.

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AbstractStrained aromatic macrocycles based on cycloparaphenylenes (CPPs) are the shortest repeating units of armchair single-walled carbon nanotubes. Since the development of several new synthetic methodologies for accessing these structures, their properties have been extensively studied. Besides the fundamental interest in these novel molecular scaffolds, their application in the field of materials science is an ongoing topic of research. Most of the reported CPP-type macrocycles display strong binding toward fullerenes, due to the perfect match between the convex and concave π-surfaces of fullerenes and CPPs, respectively. Highly functionalized CPP derivatives capable of supramolecular binding with other molecules are rarely reported. The synthesis of highly functionalized [n]cyclo-2,7-pyrenylenes leads to CPP-type macrocycles with a defined cavity capable of binding non-fullerene guests with high association constants.

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