Friday, December 21, 2007

Nanotechnology

Nanotechnology is a field of applied science and technology casing a broad range of topics. The main unifying theme is the control of matter on a scale smaller than 1 micrometre, normally in the order of 1 to 100 nanometers, as well as the fabrication of plans of this size. It is a highly multidisciplinary field, drawing from fields such as functional physics, materials science, colloidal science, appliance physics, supramolecular chemistry, and even mechanical and electrical engineering. Much speculation exists as to what new discipline and technology may result from these lines of research. Nanotechnology can be seen as an extension of accessible sciences into the nanoscale, or as a recasting of existing sciences using a newer, most recent term.

Two main approaches are used in nanotechnology. In the bottom-up approach, materials and devices are built from molecular mechanisms which assemble themselves chemically by principles of molecular appreciation. In the top-down approach, nano-objects are constructed from larger entities without atomic-level power. The impetus for nanotechnology comes from a renewed attention in colloidal science, coupled with a new invention of analytical tools such as the minute force microscope, and the scanning tunneling microscope (STM). Combined with refined processes such as electron beam lithography and molecular beam epitaxy, these instruments allow the purposeful manipulation of nanostructures, and led to the observation of novel phenomena.

Monday, December 17, 2007

Inductor

An inductor is a passive electrical device working in electrical circuits for its property of inductance. Inductance is an consequence which results from the magnetic field that forms around a current carrying conductor. Electrical current through the conductor creates a magnetic flux relative to the current. A change in this current creates a change in magnetic flux that, in turn, generates an electromotive force that acts to oppose this change in current. Inductance is a calculate of the generated emf for a unit modify in current. An inductor with an inductance of 1 henry produces an emf of 1 V when the current through the inductor changes at the rate of 1 ampere per second. The number of turns, the area of each loop/turn, and what it is wrapped around influence the inductance.

An inductor opposes changes in the current. An ideal inductor would offer no resistance to a constant direct current, however, only superconducting inductors have truly zero electrical resistance. Inductors are used expansively in analog circuits and signal processing.