scholarly journals Constructing and Visualizing Some Common Materials

2013 ◽  
pp. 186-197
Keyword(s):  
Carbon Nanotube ◽  
Lattice Structure ◽  
3D Structures ◽  
Carbon Molecules

In this exercise, students will learn how to use a modeling program to build a lattice structure. It will teach students how to construct a sheeted material such as graphite, how to construct an intercalated compound, how to construct a fullerene (buckyball, C60) and a aza-fullerene (C48N12), and how to construct a carbon nanotube from chains of carbon molecules. It aims to improve a student’s ability to visualize 3D structures.

Characterization of carbon nanotube 3D-structures infused with low viscosity epoxy resin system

2010 ◽  
Vol 92 (9) ◽  
pp. 2252-2257 ◽  
Author(s):  
Celeste M.C. Pereira ◽  
Paulo Nóvoa ◽  
Marta Martins ◽  
Stefan Forero ◽  
Felicitas Hepp ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Epoxy Resin ◽  
Resin System ◽  
3D Structures ◽  
Low Viscosity ◽  
Epoxy Resin System

Oscillation of carbon molecules inside carbon nanotube bundles

2009 ◽  
Vol 21 (14) ◽  
pp. 144214 ◽  
Author(s):  
Ngamta Thamwattana ◽  
Barry J Cox ◽  
James M Hill
Keyword(s):  
Carbon Nanotube ◽  
Nanotube Bundles ◽  
Carbon Molecules

Soldering of Carbon Nanotube Bridges using Electron Beam Deposited Gold

2003 ◽  
Vol 772 ◽  
Author(s):  
Søren Dohn ◽  
Kristian Mølhave ◽  
Dorte Nørgaard Madsen ◽  
Ramona Mateiu ◽  
Peter Bøggild ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electron Beam ◽  
Carbon Nanotube ◽  
Electrical Contact ◽  
Chemical Vapour ◽  
Pure Gold ◽  
Ambient Conditions ◽  
Multiwalled Carbon ◽  
Silicon Chips ◽  
Carbon Molecules

AbstractWe have formed suspended bridges of carbon nanotubes between microcantilevers using electron beam dissociation of metal-organic vapours. By electron beam exposure of a surface in the presence of gold-carbon molecules emitted inside an environmental scanning electron microscope, we are able to form tips and other freestanding nanostructures of high metallic content. Suspended bridges made entirely of this material exhibit resistances less than 50 times that of pure gold, and consist of dense metallic cores surrounded by a crust of nanoparticles. We used standard microfabrication techniques to produce silicon chips with multiple microcantilevers extending over the edge. Individual multiwalled carbon nanotubes grown catalyticcally by chemical vapour deposition, were positioned across two cantilevers using in-situ nanomanipulation tools. Drawing a cross-shaped gold-carbon bond on each end of the carbon nanotube consistently resulted in electrical contact with resistances in the range 1-90 Ω and linear current-voltage characteristics. We found that soldering bonds having a line width down to 10-15 nm form connections and last for days in ambient conditions.

scholarly journals Using gradient origamis to pre-program curvatures

2021 ◽  
Author(s):  
Reza Hedayati ◽  
Nima Roudbarian ◽  
Sara Tahmasiyan
Keyword(s):  
Lattice Structure ◽  
Unit Cell ◽  
Engineering Applications ◽  
Linear Gradient ◽  
3D Structures ◽  
Radial Gradient ◽  
Japanese Art ◽  
Out Of Plane

Origami structures are a traditional Japanese art which have recently found their way into engineering applications due to their powerful capability to transform flat 2D structures into complex 3D structures along their creases. Here, gradient Miura-ori origamis are introduced as a method to pre-program out-of-plane curvatures. Nine types of unit cell distributions in the origami lattice structure including checkered, linear gradient, concave radial gradient, convex radial gradient, and striped have been considered. These distributions of Miura-ori origami can create twisting, saddling, bending, local inflation, and wavy shapes, as well as their combinations when the origami lattice structure is loaded in compression.

Carbon Molecules on a Copper Substrate

Nano Hybrids ◽  
2014 ◽  
Vol 8 ◽  
pp. 1-14 ◽  
Author(s):  
Tamara Rozouvan ◽  
Igor Shaykevich ◽  
Stanislav Rozouvan
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Copper Substrate ◽  
Interface Layer ◽  
Scanning Tunneling ◽  
Quantum Mechanical ◽  
Tunneling Microscopy ◽  
Complicated Structure ◽  
Spectral Ellipsometry ◽  
Carbon Molecules

Semiconductor and metal carbon nanotubes were studied by scanning tunneling microscopy (STM) and spectral ellipsometry. STM measurements with spatial resolution up to 0.15 nm reveal spatially complicated structure of semiconductor nanotube-substrate interface layer. The measurements also registered graphene nanoclusters with hexagonal rings structure on copper. Quantum mechanical numerical calculations of electron density were performed on a carbon nanotube containing 40 atoms.

Carbon Diffusion from Methane into Walls of Carbon Nanotube through Structurally and Compositionally Modified Iron Catalyst

2011 ◽  
Vol 17 (4) ◽  
pp. 582-586 ◽  
Author(s):  
Michael J. Behr ◽  
K. Andre Mkhoyan ◽  
Eray S. Aydil
Keyword(s):  
Carbon Nanotube ◽  
Diffusion Processes ◽  
Iron Catalyst ◽  
Carbon Diffusion ◽  
Multiwall Carbon Nanotube ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Diffusion Mechanisms ◽  
Carbon Molecules ◽  
Electron Energy Loss

AbstractTo understand diffusion processes occurring inside Fe catalysts during multiwall carbon nanotube (MWCNT) growth, catalysts were studied using atomic-resolution scanning transmission electron microscopy combined with electron energy-loss spectroscopy. Nanotube walls emanate from structurally modified and chemically complex catalysts that consist of cementite and a 5 nm amorphous FeOx cap separated by a 2–3 nm thick carbon-rich region that also contains Fe and O (a-C:FexOy). Nonuniform distribution of carbon atoms throughout the catalyst base reveals that carbon molecules from the gas phase decompose near the catalyst multisection junction, where the MWCNT walls terminate. Formation of the a-C:FexOy region provides the essential carbon source for MWCNT growth. Two different carbon diffusion mechanisms are responsible for the growth of the inner and outer walls of each MWCNT.

Structural analysis of the photosynthetic membrane from Ectothiorhodospira halochloris

1983 ◽  
Vol 41 ◽  
pp. 740-741
Author(s):  
H. Engelhardt ◽  
R. Guckenberger ◽  
W. Baumeister
Keyword(s):  
Lattice Structure ◽  
Bacterial Species ◽  
Hexagonal Lattice ◽  
Reaction Centre ◽  
Photosynthetic Membrane ◽  
Rhodopseudomonas Viridis ◽  
Photosynthetic Membranes ◽  
Ectothiorhodospira Halochloris ◽  
Main Components

Bacterial photosynthetic membranes contain, apart from lipids and electron transport components, reaction centre (RC) and light harvesting (LH) polypeptides as the main components. The RC-LH complexes in Rhodopseudomonas viridis membranes are known since quite seme time to form a hexagonal lattice structure in vivo; hence this membrane attracted the particular attention of electron microscopists. Contrary to previous claims in the literature we found, however, that 2-D periodically organized photosynthetic membranes are not a unique feature of Rhodopseudomonas viridis. At least five bacterial species, all bacteriophyll b - containing, possess membranes with the RC-LH complexes regularly arrayed. All these membranes appear to have a similar lattice structure and fine-morphology. The lattice spacings of the Ectothiorhodospira haloohloris, Ectothiorhodospira abdelmalekii and Rhodopseudomonas viridis membranes are close to 13 nm, those of Thiocapsa pfennigii and Rhodopseudomonas sulfoviridis are slightly smaller (∼12.5 nm).

Electron-Channelling Patterns: Principles and Techniques

1976 ◽  
Vol 34 ◽  
pp. 400-401
Author(s):  
David C. Joy
Keyword(s):  
Crystal Structure ◽  
Electron Flux ◽  
Lattice Structure ◽  
Incident Beam ◽  
Bloch Wave ◽  
Crystalline Solid ◽  
Angle Of Incidence ◽  
Electron Channelling ◽  
Regular Arrangement ◽  
Backscattered Signals

In a crystalline solid the regular arrangement of the lattice structure influences the interaction of the incident beam with the specimen, leading to changes in both the transmitted and backscattered signals when the angle of incidence of the beam to the specimen is changed. For the simplest case the electron flux inside the specimen can be visualized as the sum of two, standing wave distributions of electrons (Fig. 1). Bloch wave 1 is concentrated mainly between the atom rows and so only interacts weakly with them. It is therefore transmitted well and backscattered weakly. Bloch wave 2 is concentrated on the line of atom centers and is therefore transmitted poorly and backscattered strongly. The ratio of the excitation of wave 1 to wave 2 varies with the angle between the incident beam and the crystal structure.

Microstructural Study of Diamond Deformed Under High Pressure and Temperature

1985 ◽  
Vol 43 ◽  
pp. 230-231
Author(s):  
E. F. Koch
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Lattice Structure ◽  
Diamond Particle ◽  
Polycrystalline Diamond ◽  
Sintering Process ◽  
Ion Milling ◽  
Sintered Compact ◽  
Transmission Electron ◽  
High Pressure Sintering

Because of the extremely rigid lattice structure of diamond, generating new dislocations or moving existing dislocations in diamond by applying mechanical stress at ambient temperature is very difficult. Analysis of portions of diamonds deformed under bending stress at elevated temperature has shown that diamond deforms plastically under suitable conditions and that its primary slip systems are on the ﹛111﹜ planes. Plastic deformation in diamond is more commonly observed during the high temperature - high pressure sintering process used to make diamond compacts. The pressure and temperature conditions in the sintering presses are sufficiently high that many diamond grains in the sintered compact show deformed microtructures.In this report commercially available polycrystalline diamond discs for rock cutting applications were analyzed to study the deformation substructures in the diamond grains using transmission electron microscopy. An individual diamond particle can be plastically deformed in a high pressure apparatus at high temperature, but it is nearly impossible to prepare such a particle for TEM observation, since any medium in which the diamond is mounted wears away faster than the diamond during ion milling and the diamond is lost.

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