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Diagram illustrating the principles used by William Wallace's eidograph. The ancient Greek engineer Hero of Alexandria described pantographs in his work Mechanics. [1]In 1603, [2] Christoph Scheiner used a pantograph to copy and scale diagrams, and wrote about the invention over 27 years later, in "Pantographice seu Ars delineandi res quaslibet per parallelogrammum lineare seu cavum" (Rome 1631).
It consists of metal pieces connected together in a scissor-like shape between a top and a bottom platform. The metal pieces acting as an adjustable lift using the scissors mechanism (or pantograph) in changing its height and also can withstand a wide range of weight. Manual laboratory scissor jack (side view)
This mechanism is used in devices such as lift tables and scissor lifts.Modern low-profile computer keyboards make an extensive use of it as well, installing each key on a scissor support to ensure their smooth vertical movement, allowing the use of a cheap and reliable rubber dome contact set, instead of expensive and complex array of mechanical switches.
In a chronoamperometry, a sudden step in potential is applied at the working electrode and the current is measured as a function of time. [8] Since this is not an exhaustive method, microelectrodes are used and the amount of time used to perform the experiments is usually very short, typically 20 ms to 1 s, as to not consume the analyte.
A subclass of voltammetry where the working electrode is a dropping mercury electrode (DME), useful for its wide cathodic range and renewable surface. [18] Rotated electrode voltammetry: A hydrodynamic technique in which the working electrode, usually a rotating disk electrode (RDE) or rotating ring-disk electrode (RRDE), is rotated at a very ...
The charged aerosol detector (CAD) is a detector used in conjunction with high-performance liquid chromatography (HPLC) and ultra high-performance liquid chromatography (UHPLC) to measure the amount of chemicals in a sample by creating charged aerosol particles which are detected using an electrometer.
As the name implies, STM utilizes the tunneling charge transfer principle from tip to surface or vice versa, thereby recording the current response. This concept originates from a particle in a box concept; if potential energy for a particle is small, the electron may be found outside of the potential well, which is a classically forbidden region.
Electrochemical stripping analysis is a set of analytical chemistry methods based on voltammetry [1] or potentiometry [2] that are used for quantitative determination of ions in solution. [3] Stripping voltammetry (anodic, cathodic and adsorptive) have been employed for analysis of organic molecules as well as metal ions.