coulomb

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Related to coulombic: magnetic force, Coulomb potential

SI units

 
the units of measurement generally accepted for all scientific and technical uses; together they make up the International System of Units. (See also metric system.) The abbreviation SI, from the French Système International d'Unités, is used in all languages. There are seven base SI units, defined by specified physical measurements, and two supplementary units. Units are derived for any other physical quantities by multiplication and division of the base and supplementary units. The derived units with special names are shown in the accompanying table.



SI is a coherent system. This means that units are always combined without conversion factors. The derived unit of velocity is the meter per second (m/s); the derived unit of volume is the cubic meter (m3). If you know that pressure is force per unit area, then you know that the SI unit of pressure (the pascal) is the unit of force divided by the unit of area and is therefore equal to 1 newton per square meter.

The metric prefixes can be attached to any unit in order to make a unit of a more convenient size. The symbol for the prefix is attached to the symbol for the unit, e.g., nanometer (nm) = 10−9 m. The units of mass are specified in terms of the gram, e.g., microgram (μg) = 10−9 kg.

Only one prefix is used with a unit; the use of units such as the millimicrometer is no longer acceptable. When a unit is raised to a power, the power applies to the prefix as well, e.g., a cubic millimeter (mm3) = 10−9 m3. When a prefix is used with a ratio unit, it should be in the numerator rather than in the denominator, e.g., kilometers/second (km/s) rather than meters/millisecond (m/ms). Only prefixes denoting powers of 103 are normally used. Hecto-, deka-, deci-, and centi- are usually attached only to the metric system units gram, meter, and liter.

Owing to the force of tradition, one noncoherent unit, the liter, equal to 10−3 m3, or 1 dm3, is generally accepted for use with SI. The internationally accepted abbreviation for liter is the letter l; however, this can be confused with the numeral 1, especially in typescript. For this reason, the capital letter L is also used as a symbol for liter. The lower case letter is generally used with prefixes, e.g., dl, ml, fl. The symbols for all other SI units begin with a capital letter if the unit is named after a person and with a lower case letter otherwise. The name of a unit is never capitalized.

Coulomb

(kū-lohm),
Charles A. de, French physicist, 1736-1806. See: coulomb.

cou·lomb (C, Q),

(kū-lom'),
The unit of electrical charge, equal to 3 × 109 electrostatic units; the quantity of electricity delivered by a current of 1 A in 1 s equal to 1/96,485 faraday.
[CA de Coulomb, Fr. physicist, 1736-1806]

cou·lomb

(C) (kū'lom)
The SI unit of electrical charge, equal to 3 × 109 electrostatic units; the quantity of electricity delivered by a current of 1 ampere in 1 sec; equal to 1/96,485 faraday; also used to measure radiation.
See also: roentgen
[CA de Coulomb, Fr. physicist, 1736-1806]
References in periodicals archive ?
Samples Coulombic efficiency Voltage efficiency (%) (%) N-117 82 87 NM-1H 94 87 Samples Energy efficiency (%) N-117 71 NM-1H 82
We surmise that the Si nanoscale grains in the composite help to occlude Li ions with high coulombic efficiency during the first charge-discharge cycle; moreover, the [Cu.sub.3]Si nanoscale grains act as an electrically conductive material.
J.D.: Coulombic efficiency is the ratio of the amount of charge obtained from the battery during the discharge, compared to the amount of charge that was stored in the battery during the charge.
In addition to coulombic forces, the non-ionic interactions between the dye molecules and the polymer side-chains contribute towards the binding mechanism.
This researcher found that classical dynamical calculations for the ground-state hydrogen molecule using a Coulombic force between the bond electrons along with spectroscopic data yielded a vibrational frequency of 2.20 x [10.sup.14] Hz, which was a significant deviation from the experimentally determined value of 1.38 X [10.sup.14] Hz.
The "brightener," by coulombic attraction, forms a layer on the surface where the additive assists in the refinement of the copper grain structure as it is deposited.
Sun and Stirner (2001) used molecular dynamics to study the compression of 2-D polystyrene particles at an oil-water interface through monopole-monopole Coulombic interactions.
In contrast, when we used PAMAM dendrimers with negatively charged carboxyl groups at the outer sphere, we could not detect any negatively charged oligonucleotides after the slides were washed, indicating coulombic repulsion.
The adsorption of cationic polyacrylamides by clays occurs through electrostatic (Coulombic) interactions between the cationic groups on the polyacrylamide and the negatively charged sites on the clay surface (Harris et al.
Significant tailing was observed due to the Coulombic interaction of the positively charged dyes with the deprotonated silanol groups of the capillary wall (Weinberger 2000).
These droplets have high charge density and coulombic forces cause them to split into successively smaller units until individual charged molecules are released.
As is seen in (1), Cornell potential has two parts: one is the Coulombic term and the other is the linear part.