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Nanotechnology, the science and technology of precisely controlling the structure of matter at the molecular level, is widely viewed as the most significant technological frontier currently being explored. Materials and devices at the nanoscale (a nanometer is one billionth of one meter) hold vast promise for innovation in virtually every industry and public endeavor including health, electronics, transportation, the environment and national security, and has been heralded as "the next industrial revolution."

Computational Nanotechnology He-Buckyball Flow in Nanotubes Image courtesy of Oak Ridge National Laboratory

Some likely implications of nanotechnology::
computers: 1000 times faster and cheaper than current models; biological: nanomachines that fix cancerous cells; bridges and roads made of unbreakable diamond strands; houses that can repair themselves or change shape on command
See text of Richard Feynman's visionary 1959 talk

n-body simulation: simulation which calculates the effects of a force field on atoms in a gas or a fluid. This is an example of a problem using dependent variables.

network: a system in which one or more computers are connected to each other and sharing resources.

Nuclear Magnetic Resonance (NMR) NMR is a phenomenon which occurs when the nuclei of certain atoms are immersed in a static magnetic field and exposed to a second oscillating magnetic field. Some nuclei experience this phenomenon, and others do not, dependent upon whether they possess a property called spin.

NMR Spectroscopy A substance is placed in a magnetic field. Some atomic nuclei (e.g. protons, nuclei of hydrogen atoms) then behave like microscopic compass needles, called nuclear spins. Each nuclear spin orientation corresponds to a different energy level. The spins may jump between the levels when the sample is exposed to radio waves whose frequency exactly matches the energy spacing. This is called resonance. One way of measuring the energy level spacings is to change the irradiation frequency slowly. At resonance, the spins flip and an electric signal is induced. The strength of the signal is plotted as a function of frequency in a diagram, the NMR spectrum.

Around 1950, it was discovered that the nuclear resonance frequencies depended not only on the nature of the atomic nuclei, but also on their chemical environment. The utility of NMR in chemistry soon became obvious: The signals could be used to determine the number and type of chemical groups in a compound. NMR spectroscopy is routinely used by chemists to study chemical structure using simple one-dimensional techniques. Two-dimensional techniques are used to determine the structure of more complicated molecules. These techniques are replacing x-ray crystallography for the determination of protein structure. Time domain NMR spectroscopic techniques are used to probe molecular dynamics in solutions. Solid state NMR spectroscopy is used to determine the molecular structure of solids. Other scientists have developed NMR methods of measuring diffusion coefficients.
The versatility of NMR makes it pervasive in the sciences. Scientists and students are discovering that knowledge of the science and technology of NMR is essential for applying, as well as developing, new applications for it.

Images courtesy of Nobel Museum
see also solution NMR

non-Coding DNA is the strand of DNA that does not carry the information necessary to make a protein. The non-coding strand is the mirror image of the coding strand and is also known as the antisense strand.

Nucleic Acid A complex organic compound in living cells that consists of a chain of nucleotides. There are two types: DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid). See DNA and RNA for details.

Nucleotide is one of the structural components, or building blocks, of DNA and RNA. A nucleotide consists of a base (one of four chemicals: adenine, thymine, guanine, and cytosine) plus a molecule of sugar and one of phosphoric acid.

Nucleus (in biology) is the central cell structure that houses the chromosomes.

null: Nothing. Empty. Zero. A "null packet" is one that does not contain any information; it usually means that the network's transport layer is clear and ready for a new packet.

Author: Tug Sezen