04-04-2012, 11:41 PM
i need a seminar presentation and report on the topic, nanotechnology and carbon nano tubes
04-04-2012, 11:41 PM
i need a seminar presentation and report on the topic, nanotechnology and carbon nano tubes
05-04-2012, 09:21 AM
to get information about the topic "nanotechnology and carbon nanotubes" full report ppt and related topic refer the link bellow
https://seminarproject.net/Thread-carbon...ull-report https://seminarproject.net/Thread-carbon...ort?page=4 https://seminarproject.net/Thread-carbon...ort?page=3 https://seminarproject.net/Thread-carbon...2#pid65932 https://seminarproject.net/Thread-nanote...ocomputing https://seminarproject.net/Thread-carbon...ubes--1353
30-06-2012, 05:20 PM
Nanotechnology and Carbon Nanotubes Nanotechnology and Carbon Nanotubes.doc (Size: 3.68 MB / Downloads: 59) Abstract: Carbon NanoTube is a new molecular form of carbon which exhibits a series of fundamentally new and unexpected physical, mechanical and chemical properties and brought into the position of one of the most promising tools in future nanotechnology. This paper presents various technologies for fabricating Carbon Nano Tubes (CNT’s) and their properties which mainly describe structural behavior of CNT’s. The major application of CNT’s is Carbon Nanotube FET which is going replace current Si devices, discussed completely. Other applications are discussed in detail with possible limitations. Nanotubes are promising a wide variety of applications in every industrial area changing the basics of all materials. In nanotechnology the invention of the nanotubes is really a jolt. Introduction: Nanotechnology means something far more ambitious, miniature submarines in the bloodstream, little cogs and gears made out of atoms, space elevators made of nanotubes, and the colonization of space. Through electron microscopy, scanning probe microscopes or simply growing and analyzing thin films. A Simple Carbon Nano Tube Nanotubes have a very broad range of electronic, thermal, and structural properties that change depending on the different kinds of nanotube (defined by its diameter, length, and chirality, or twist). To make things more interesting, besides having a single cylindrical wall (SWNTs), nanotubes can have multiple walls (MWNTs)--cylinders inside the other cylinders. Carbon Nano Tubes Fabrication is the main concern, since the whole cost of the manufacturing can be reduced by using sophisticated systems. Following sections shows different Fabrication techniques and Carbon Tubes properties. Fabrication and Synthesis of CNT: Different techniques for nanotubes synthesis and their current status are briefly explained here. Carbon nanotubes are generally produced by three main techniques Arc discharge, Laser ablation and Chemical vapour deposition. The growth mechanism is almost general for all techniques. In arc discharge, a vapour is created by an arc discharge between two carbon electrodes with or without catalyst. Nanotubes self-assemble from the resulting carbon vapour. In the laser ablation technique, a high-power laser beam impinges on a volume of carbon -containing feedstock gas (methane or carbon monoxide). At the moment, laser ablation produces a small amount of clean nanotubes, whereas arc discharge methods generally produce large quantities of impure material. In general, chemical vapour deposition (CVD) results in MWNTs or poor quality SWNTs. Visualization of possible carbon nanotube growth mechanisms. There are several theories on the exact growth mechanism for nanotubes. One theory postulates that metal catalyst particles are floating or are supported on graphite or another substrate. It presumes that the catalyst particles are spherical or pear-shaped, in which case the deposition will take place on only one half of the surface (this is the lower curvature side for the pear shaped particles). The carbon diffuses along the concentration gradient and precipitates on the opposite half, around and below the bisecting diameter. However, it does not precipitate from the apex of the hemisphere, which accounts for the hollow core that is characteristic of these filaments. For supported metals, filaments can form either by "extrusion (also known as base growth)" in which the nanotube grows upwards from the metal particles that remain attached to the substrate, or the particles detach and move at the head of the growing nanotube, labeled "tip-growth". Depending on the size of the catalyst particles, SWNT or MWNT are grown. In arc discharge, if no catalyst is present in the graphite, MWNT will be grown on the C2-particles that are formed in the plasma. |
|