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Optical Trapping
Optical tweezers (originally called single-beam gradient force trap) are scientific instruments that use a highly focused laser beam to hold and move microscopic and sub-microscopic objects like atoms, nanoparticles and droplets, in a manner similar to tweezers. If the object is held in air or vacuum without additional support, it can be called optical levitation. The laser light provides an attractive or repulsive force (typically on the order of piconewtons), depending on the relative refractive index between particle and surrounding medium. Levitation is possible if the force of the light counters the force of gravity. The trapped particles are usually micron-sized, or even smaller. Dielectric and absorbing particles can be trapped, too. Optical tweezers are used in biology and medicine (for example to grab and hold a single bacterium, a cell like a sperm cell or a blood cell, or a molecule like DNA), nanoengineering and nanochemistry (to study and build materials from singl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Instrument
A scientific instrument is a device or tool used for scientific purposes, including the study of both natural phenomena and theoretical research. History Historically, the definition of a scientific instrument has varied, based on usage, laws, and historical time period. Before the mid-nineteentcenturysuch tools were referred to as "natural philosophical" or "philosophical" apparatus and instruments, and older tools from antiquity to the Middle Ages (such as the astrolabe and pendulum clock) defy a more modern definition of "a tool developed to investigate nature qualitatively or quantitatively." Scientific instruments were made by instrument makers living near a center of learning or research, such as a university or research laboratory. Instrument makers designed, constructed, and refined instruments for purposes, but if demand was sufficient, an instrument would go into production as a commercial product. In a description of the use of the eudiometer by Jan Ingenhousz to show ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
