The field of electronics comprises the study and use of systems that operate by controlling the flow of electrons (or other charge carriers) in devices such as thermionic valves (vacuum tubes) and semiconductors. The design and construction of electronic circuits to solve practical problems is an integral technique in the field of electronics engineering and is equally important in hardware design for computer engineering. All applications of electronics involve the transmission of either information or power. Most deal only with information.
The study of new semiconductor devices and surrounding technology is sometimes considered a branch of physics. This article focuses on engineering aspects of electronics. Other important topics include electronic waste and occupational health impacts of semiconductor manufacturing.
Source From Wikipedia, the free encyclopedia
Nanotechnology is a field of applied science and technology covering a broad range of topics. The main unifying theme is the control
of matter on a scale smaller than one micrometre, as well as the fabrication of devices on this same length scale. It is a highly multidisciplinary field, drawing from fields
such as colloidal science, device physics, and supramolecular chemistry. Much speculation exists as to what new science and technology might result from these lines of research. Some view nanotechnology
as a marketing term that describes pre-existing lines of research applied to the sub-micron size scale.
Despite the apparent simplicity of this definition, nanotechnology actually encompasses diverse lines of inquiry. Nanotechnology
cuts across many disciplines, including colloidal science, chemistry, applied physics, biology. It could variously be seen as an extension of existing sciences into the nanoscale, or as a recasting of existing sciences
using a newer, more modern term. Two main approaches are used in nanotechnology: one is a "bottom-up" approach where materials
and devices are built from molecular components which assemble themselves chemically using principles of molecular recognition; the other being a "top-down" approach where nano-objects are constructed from larger entities without atomic-level control.
The impetus for nanotechnology has stemmed from a renewed interest in colloidal science, coupled with a new generation
of analytical tools such as the atomic force microscope (AFM) and the scanning tunneling microscope (STM). Combined with refined processes such as electron beam lithography, these instruments allow the deliberate manipulation of nanostructures, and in turn led to the observation of novel phenomena.
Nanotechnology is also an umbrella description of emerging technological developments associated with sub-microscopic dimensions.
Despite the great promise of numerous nanotechnologies such as quantum dots and nanotubes, real applications that have moved
out of the lab and into the marketplace have mainly utilized the advantages of colloidal nanoparticles in bulk form, such
as suntan lotion, cosmetics, protective coatings, and stain resistant cloth