05-02-2013, 09:50 AM
NANO SCIENCE AND NANO TECHNOLOGY
[attachment=49615]
ABSTRACT
The goal of nano technology is to manipulate individual atoms and place them in pattern to produce designed structure. Assemblers and replicators will work together to automatically construct, manipulate atoms and produce any kind of material atoms at decreased manufacturing cost and increased goods strength. The bottom-up techniques build or grow larger structures atom by combining small molecules, where as in the top-down fabrication techniques a bulk material is reduced in size to form nanoscale pattern. The main method to produce nano materials are the sol-gel synthesis, condensation, mechanical alloying or by electro deposition. The basic carbon nano materials are found in 3 dimensional structures and can be rolled into sheets. In the carbon fiber, the individual layers of graphite are much larger, thin and stronger .The rolled 3 dimensional structures is fullerenes and cylindrical nanotubes. They can handle 60 carbon atoms and it’s finding a group of hexagon in its structure, called buckminsterfullerene c60. The main parameters determining their type are diameter and chirality. The nanowires are consists of dimensions of a nanometer of10-9meters which are non-crystalline spiral shaped. The carbon nanotubes are capable of storing the hydrogen, which is the energy-efficient and environment-friendly road transportation. Plastic Solar cells are made of single layer of plastic sandwiched between two conductive electrodes. Major benefits of nanotechnology include improved manufacturing methods, water purification systems, energy systems, nano-medicine, better food production methods and nutrition and large scale infrastructure auto-fabrication .The major areas of usage are engine covers, timing belts covers, impellers& blades for vacuum cleaners, mirrors housing on vehicles, electronic devices. Researchers have found that when rats breathed in nanoparticles, the particles settled in the brain and lungs, which led to significant increases in biomarkers for inflammation and stress response and those nanoparticles, induce skin aging through oxidative stress in hairless mice.
STEM
The de Broglie wavelength equation relates the velocity of the Electron with its wavelength,λ=h/mv(h-planck’s constant, m-mass of electron and v-velocity). Quantum is a branch of physics dealing with physical phenomena at microscopic scales, where the action is on the order of the Planck’s constant. STEM is the hybrid instrument combining the features of both SEM (Scanning Electron microscope) and TEM (Transmission Electron microscope). The same probe beam can in TEM can be demagnetized and used as probe beam that can be scanned over the samples. The normal bright field image is made with no-loss electrons from the central beam. Dark field images are made with electrons deflected from the beam axis with or without energy loss. Deflection coils placed after the samples are used to direct the chosen part of the diffraction pattern to the entrance aperture of the spectrometer. Common dark field STEM images are collected by imaging part of the diffraction pattern outside the central beam spot.
CARBON NANOTUBES
Synthesis and Purification
Carbon nanotubes were first noticed in the graphitic soot deposited on the negatively charged electrode used in the arc-discharge synthesis of fullerenes. The graphite rods are evaporated in a dynamic atmosphere of helium typically a pressure of 130 torr of helium is used and the arc is run at 30V dc with current being maintained at~180A. The carbon deposited on the cathode has a soft inner core and a hard outer cover. The tube’s inner diameter, interlayer spacing, length also chiral angle Ɵ can be determined from the TEM images. While the first three are straightforward from a high resolution image, the determination of the chiral angle necessitates measurement of the interference pattern.
CONCLUSION:
Apart from the above fields, nanotechnologies are used in the following areas: Micro electromechanical Systems (MEMS), Nanoparticles for Destroying Bacteria, Liquids Driven by Light, Inkjet Printing at Nanometer Scale, Space Elevator, Radiation Shielding, Nan lube could make possible ultra-dense memory for Storage in computing.
[attachment=49615]
ABSTRACT
The goal of nano technology is to manipulate individual atoms and place them in pattern to produce designed structure. Assemblers and replicators will work together to automatically construct, manipulate atoms and produce any kind of material atoms at decreased manufacturing cost and increased goods strength. The bottom-up techniques build or grow larger structures atom by combining small molecules, where as in the top-down fabrication techniques a bulk material is reduced in size to form nanoscale pattern. The main method to produce nano materials are the sol-gel synthesis, condensation, mechanical alloying or by electro deposition. The basic carbon nano materials are found in 3 dimensional structures and can be rolled into sheets. In the carbon fiber, the individual layers of graphite are much larger, thin and stronger .The rolled 3 dimensional structures is fullerenes and cylindrical nanotubes. They can handle 60 carbon atoms and it’s finding a group of hexagon in its structure, called buckminsterfullerene c60. The main parameters determining their type are diameter and chirality. The nanowires are consists of dimensions of a nanometer of10-9meters which are non-crystalline spiral shaped. The carbon nanotubes are capable of storing the hydrogen, which is the energy-efficient and environment-friendly road transportation. Plastic Solar cells are made of single layer of plastic sandwiched between two conductive electrodes. Major benefits of nanotechnology include improved manufacturing methods, water purification systems, energy systems, nano-medicine, better food production methods and nutrition and large scale infrastructure auto-fabrication .The major areas of usage are engine covers, timing belts covers, impellers& blades for vacuum cleaners, mirrors housing on vehicles, electronic devices. Researchers have found that when rats breathed in nanoparticles, the particles settled in the brain and lungs, which led to significant increases in biomarkers for inflammation and stress response and those nanoparticles, induce skin aging through oxidative stress in hairless mice.
STEM
The de Broglie wavelength equation relates the velocity of the Electron with its wavelength,λ=h/mv(h-planck’s constant, m-mass of electron and v-velocity). Quantum is a branch of physics dealing with physical phenomena at microscopic scales, where the action is on the order of the Planck’s constant. STEM is the hybrid instrument combining the features of both SEM (Scanning Electron microscope) and TEM (Transmission Electron microscope). The same probe beam can in TEM can be demagnetized and used as probe beam that can be scanned over the samples. The normal bright field image is made with no-loss electrons from the central beam. Dark field images are made with electrons deflected from the beam axis with or without energy loss. Deflection coils placed after the samples are used to direct the chosen part of the diffraction pattern to the entrance aperture of the spectrometer. Common dark field STEM images are collected by imaging part of the diffraction pattern outside the central beam spot.
CARBON NANOTUBES
Synthesis and Purification
Carbon nanotubes were first noticed in the graphitic soot deposited on the negatively charged electrode used in the arc-discharge synthesis of fullerenes. The graphite rods are evaporated in a dynamic atmosphere of helium typically a pressure of 130 torr of helium is used and the arc is run at 30V dc with current being maintained at~180A. The carbon deposited on the cathode has a soft inner core and a hard outer cover. The tube’s inner diameter, interlayer spacing, length also chiral angle Ɵ can be determined from the TEM images. While the first three are straightforward from a high resolution image, the determination of the chiral angle necessitates measurement of the interference pattern.
CONCLUSION:
Apart from the above fields, nanotechnologies are used in the following areas: Micro electromechanical Systems (MEMS), Nanoparticles for Destroying Bacteria, Liquids Driven by Light, Inkjet Printing at Nanometer Scale, Space Elevator, Radiation Shielding, Nan lube could make possible ultra-dense memory for Storage in computing.