SI unit


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unit

 [u´nit]
1. a single thing; one segment of a whole that is made up of identical or similar segments.
2. a specifically defined amount of anything subject to measurement, as of activity, dimension, velocity, volume, or the like.
3. a distinct part of a hospital, usually having a specific physical location and serving a defined function; see under names of specific units.
Ångström unit angstrom.
atomic mass unit (u) (amu) the unit of mass equal to ¹⁄₁₂ the mass of the nuclide of carbon 12. Called also dalton.
autonomous nursing unit a nursing unit under a decentralized administration system in which the staff is responsible for all aspects of unit functioning.
British thermal unit (BTU) a unit of heat formerly widely used, being the amount necessary to raise the temperature of 1 pound of water from 39° to 40°F., equal to approximately 252 calories.
CH50 unit the amount of complement that will lyse 50 per cent of a standard preparation of sheep red blood cells coated with antisheep erythrocyte antibody.
continuing education unit (CEU) a unit of credit for educational offerings given to professional persons, determined by a professional organization according to a mathematical formula after a thorough review of the program of study, the qualifications of the instructors, and the program objectives.
critical care unit intensive care unit.
electrostatic u's (esu) that system of units that is based on the fundamental definition of a unit charge as one that will repel a similar charge with a force of 1 dyne when the two charges are 1 cm apart in a vacuum.
environmental control unit a computerized system that allows the handicapped individual to operate several different appliances using a keyboard or other input device.
heat unit the amount of heat energy that is produced by one kVp (kilovolt peak) and one mA (milliampere) for one second with single phase, full wave rectified radiographic equipment.
Hounsfield unit an arbitrary unit of x-ray attenuation used for CT scans. Each voxel is assigned a value on a scale in which air has a value of −1000; water, 0; and compact bone, +1000.
intensive care unit see intensive care unit.
International unit (IU)
1. a unit of enzyme activity equal to the amount of enzyme that catalyzes the conversion of one micromole of substrate or coenzyme per minute under specified conditions (temperature, pH, and substrate concentration) of the assay method. Abbreviated U.
2. any of several arbitrary units that have been adopted by international bodies to express the quantities of certain vitamins (A, C, D, and thiamine hydrochloride), hormones (androgen, chorionic gonadotropin, estradiol benzoate, estrone, insulin, progesterone, and prolactin), and drugs (digitalis and penicillin).
Kienböck's unit a unit of x-ray exposure equal to 0.1 erythema dose; symbol X.
motor unit the unit of motor activity formed by a motor nerve cell and its many innervated muscle fibers.
postanesthesia care unit (PACU) a specialty unit in a hospital for giving postanesthesia care (care of patients recovering from anesthesia and intravenous sedation); formerly called recovery room.
radiologic u's units used to measure radiation, including roentgens, rads, rems, and curies.
u's of service (UOS)
1. the number of procedures done by a department.
2. individuals or groups of individuals who are the recipients of nursing care.
short procedures unit (short term care unit) a nursing unit where patients are briefly cared for following a medical or surgical procedure and are then discharged without spending the night.
SI unit any unit of the International System of units (the metric system); see also si units.
step-down unit a nursing unit designated to provide care for patients who are stable enough to be discharged from the intensive care unit but are not yet ready to be cared for on a medical-surgical unit.
Svedberg unit (S) a unit equal to 10−13 second used for expressing sedimentation coefficients of macromolecules.
Svedberg flotation unit (Sf) a unit equal to 10−13 second used for expressing negative sedimentation coefficients of macromolecules that float rather than sink in a centrifuge, e.g., lipoproteins.
terminal respiratory unit the functional unit of the lung, including a respiratory bronchiole, alveolar ducts and sacs, and alveoli; called also primary lobule of lung and primary respiratory lobule.
USP unit one used in the United States Pharmacopeia for expressing potency of drugs and other preparations.

SI unit 

Abbreviation of Système International d'unités (or International System of Units). It is derived from the metric system of physical units. There are seven base units, two supplementary units and many derived units. See candela per square metre; lumen; lux; micrometre (micron); nanometre.
Table S2 Base and supplementary SI units, and some derived units
physical quantitynamesymbol
base units
lengthmetrem
masskilogramkg
timeseconds
electric currentampereA
thermodynamic temperaturekelvinK
luminous intensitycandelacd
amount of substancemolemol
supplementary units
plane angleradianrad
solid anglesteradiansr
some derived units
areasquare metrem2
electric potential differencevoltV
electric resistanceohmΩ
energyjoule
forcenewtonN
frequencyhertzHz
illuminanceluxlx
luminancecandela per square metrecd/m2
luminous fluxlumenlm
powerwattW
velocitymetre per secondm/s
volumecubic metrem3

unit

1. a single thing; one segment of a whole that is made up of identical or similar segments.
2. a specifically defined amount of anything subject to measurement, as of activity, dimension, velocity, volume, or the like.

Angstrom unit
atomic mass unit
see dalton.
International unit
1. see si units.
2. a unit of enzyme activity equal to the amount of enzyme that catalyzes the conversion of one micromole of substrate or coenzyme per minute under specified conditions (temperature, pH and substrate concentration) of the assay method. Abbreviated U.
3. any of several arbitrary units that have been adopted by international bodies to express the quantities of certain vitamins (A, C, D and thiamin hydrochloride), hormones (androgen, chorionic gonadotropin, estradiol benzoate, estrone, insulin, progesterone and prolactin), and drugs (digitalis and penicillin).
SI unit
any unit of the International System of units (the metric system). See si units.
References in periodicals archive ?
12] Hz to be equal to exactly 683 when it is expressed in the SI unit [s.
All tables and figures will also be presented in SI units.
Since the development of the International System of Units (SI), many experiments have been developed in order to realize SI units to ever lower levels of uncertainty.
This all rather supports my long-held contention that we would get along much better sticking to pounds and ounces and feet and inches rather than SI units, especially when incorrectly converted.
The SI units of measurement are treated as mathematical entities (e.
All CVs calculated in DCCT units were much lower compared with CVs calculated in SI units (Table 1) owing to the lower specificity of the NGSP PRMP.
Although electric and magnetic dimensions in systems CGSE and CGSM are expressed in the terms of mass, length, and time units (in SI units Ampere was added), they seem strange and bizarre.
The DIVA automatically compensates for changes in steam density, providing 4-20-mA and pulsed outputs proportional to mass or energy flow, as well as real time display of steam pressure, temperature, flow rate and total flow in both English and SI units.
SI units are used throughout the book, and it contains 1,150 illustrations.
The initial 300 questions cover topics including SI units, behaviour of gases and liquids, temperature measurement, equipment considerations (valves, vaporisers and ventilators).
The new site connects with IDES Prospector, a database comprised of polymer property data in all standards with information in English and SI units.