Nanotechnology by xiuliliaofz

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									Nanotechnology




                 Nanotechnology
Nanotechnology




                 Nanotechnology: General Information and Background


                  Nanotechnology is a concept, a term that refers to many different
                   technologies.
                  All of these technologies are extremely small in scale – ―nano‖ is a
                   measurement that refers to the nanometre or 10-9 m.
                  A nanometre is the width of 10 hydrogen atoms lined up side-by-side. To
                   put this in perspective, a human hair is about 80,000 nanometres wide; the
                   head of a pin is about 1 million nanometres wide; a red blood cell is about
                   7,000 nanometres in diameter
                  A nanometer is the amount a man's beard grows in the time it takes him to
                   raise the razor to his face
                  The raw materials and some of the products of nanotechnology are all
                   extremely small in physical scale.
                  Nanoscience and nanotechnology often focus on the manipulation of the
                   most basic components of all matter — atoms and molecules — with great
                   precision
Nanotechnology




                 Nanotechnology: General Information and Background


                 Public Health and Toxicity Concerns
                  Public health concerns about nanotechnology products focus on
                   interactions between them and biological tissues and processes.
                  Some nanostructures may accumulate within tissues and organs and can
                   be taken up by individual cells.
                  Nanoscale particles and structures into cells do not seem to affect the
                   immune responses of cells that introducing larger particles and structures
                   do.
                  This ability not to trigger the immune system may be an advantage in
                   targeting specific cells with introduced drugs, but the particles may still have
                   some unintended effects. This means that nanostructures. although
                   attractive as potential drug delivery mechanisms may be a health hazard.

                  The extremely small size of nanostructures leads some to worry that the
                   structures might enter the food chain undetected.
    Nanotechnology


•     Materials reduced to the nanoscale can show different properties compared to
      what they exhibit on a macroscale, enabling unique applications.

•     For instance, opaque substances become transparent (copper); stable
      materials turn combustible (aluminum); solids turn into liquids at room
      temperature (gold); insulators become conductors (silicon).

•     A material such as gold, which is chemically inert at normal scales, can serve
      as a potent chemical catalyst at nanoscales. Much of the fascination with
      nanotechnology stems from these quantum and surface phenomena that matter
      exhibits at the nanoscale.

Lubick, N. (2008). Silver socks have cloudy lining. Environ Sci Technol. 42(11):3910 quoted in WikiPedia
Nanotechnology




                 Nanotechnology: General Information and Background

                        Nanomedicine:

                        Suggested applications in nanomedicine include:

                       Rapid cardiovascular repair
                       Treatments for pathogenic disease and cancer
                       Responses to physical traumas, with new methods of first aid
                       Surgery, and emergency or critical care
                       Neurography, spinal restoration and brain repair (nanostructures)
                       Nutrition and digestion
                       Reproductive modifications
                       Cosmetics
                       Sports and recreation – performance augmentation
                       Veterinary and space medicine
                       Strategies for biostasis and the control of aging processes;
                       human augmentation systems



                  By: Donald E. Marlowe
    The molecular-assembler concept


• Controlled molecular assembly : molecular assemblers will position
  molecules, bringing them together in a specific position, orientation, and
  sequence.

• By holding and positioning molecules, assemblers will control how the
  molecules react, building complex structures with atomically precise
  control.

• The parts are nanometer scale, and the transferred parts are just a few
  atoms large, shifting from handle to workpiece through a chemical
  reaction at a specific site.

• An assembler will work as part of a larger system that prepares tools,
  puts them on the conveyor, and controls the programmable positioning
  mechanism
   The molecular-assembler concept


• Their small moving parts will enable them to operate at high frequencies:
  because each motion traverses less than a millionth of a meter, each
  can be completed in less than a millionth of a second.

• This enables extremely high productivity.

• Machines of this sort will be complex systems that are several
  technology generations away. Indeed, no one is even trying to directly
  build molecular assemblers today, because nanotechnology is still in its
  infancy.

• We can see a path to assemblers and the early machines may resemble
  the small, simple productive nanosystems in nature and in
  biotechnology.
  Molecular Manufacturing


• Molecular manufacturing will bring both great opportunities and great
  potential for abuse.

• Advanced systems could be used to build large, complex products
  cleanly, efficiently, and at low cost.

• Building with atomic precision, desktop-scale (and larger)
  manufacturing systems could produce the products like the following,
  with consequences for many global problems:

          • Inexpensive, efficient solar energy systems, a renewable, zero-carbon
            emission source
          • Desktop computers with a billion processors
          • Medical devices able to destroy viruses and cancer cells without
            damaging healthy cells
          • Materials 100 times stronger than steel
          • Superior military systems
          • More molecular manufacturing systems
Nanotechnology Molecular Manufacturing


     Nanotechnology: General Information and Background




                                         In Nanosystems, Dr. Drexler proposed and analyzed a variety of molecular
                                         machines, including some too large to be specified and analyzed in atomic
                                         detail. One such machine was a sorting rotor based upon modulated
                                         receptors designed to bind and transport chemical species from a feedstock
                                         solution. One of Dr. Drexler’s more recent projects has been to design in
                                         atomic detail a simpler pump intended to provide some of the functionality of
                                         the larger and more complex sorting rotors.

                                         The pump and segment of chamber wall pictured here contain 6165 atoms.
Nanopore sensor

                       Nanopore Sensor
                       Applied voltage draws a DNA strand
                       and surrounding ionic solution
                       through a pore of nanometer
                       dimensions. The various DNA units
                       in the strand block ion flow by
                       differing amounts. In turn, by
                       measuring these differences in ion
                       current, scientists can detect the
                       sequence of DNA units. Atomistic
                       scale simulations performed on the
                       NASA Columbia supercomputer
                       (SGI Altix-3000) allow detailed study
                       of DNA translocation to enhance the
                       abilities of these sequencers. Solid-
                       state nanopores offer a better
                       temporal control of the translocation
                       of DNA, and a more robust template
                       for nano-engineering than biological
                       ion channels. The chemistry of solid-
                       state nanopores can be more easily
                       tuned to increase the signal
                       resolution. These advantages will
                       results in real-time genome
                       sequencing..




                  NASA Ames nanotechnology
Nanowire




Nanolasers
The complex interaction between light and nanometer structures, like wires, has possibilities as new
technology for devices and sensors. NAS researchers are studying light emission from a semiconductor
nanowire-typically 10-100 nanometers wide and a few micrometers long-which functions as a laser.
Lasers made from arrays of these wires have many potential applications in communications and sensing
for NASA.




                                                                    NASA Ames nanotechnology
AN ENGINEERED DNA STRAND




       An engineered DNA strand between metal atom contacts
           could function as a molecular electronics device.
           Such molecules and nanostructures are expected to
           revolutionize electronics. Understanding the
           complex quantum physics involved via simulation
           guides design.




                    NASA Ames nanotechnology
Carbon Nanotubes - SEM Images
•   Neural tree with 14 symmetric Y-junctions
•   Branching and switching of signals at each junction similar to what happens in biological
    neural network
•   Neural tree can be trained to perform complex switching and computing functions
•   Not restricted to only electronic signals; possible to use acoustic, chemical or thermal
    signals
           A novel data storage
           system capable of
           1015 bytes/cm2 is being
           explored.

           In this system, H atoms
           would be designated as 0
           and F atoms as 1.


           A tip that can distinguish
           between 0 and 1 rapidly
           and unambiguously
           is being investigated.




NASA Ames nanotechnology
 Nano and BioTechnology Research at NASA Ames
        M. Meyyappan and Harry Partridge
           NASA Ames Research Center
              Moffett Field, CA 94035

Abstract
This article provides an overview of nanotechnology and
biotechnology research at NASA Ames Research Center
and covers current results in the areas of carbon
nanotube (CNT) growth and characterization and
functionalization, nanotubes in scanning probe
microscopy, inorganic nanowires, biosensors, chemical
sensors, nanoelectronics optoelectronics, computational
nanotechnology, quantum device simulation, and
computational optoelectronics.

Link to Report

								
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