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6 result(s) found where the letter starting with "U"

UI
Unit Interval.
 

Uncertainty
The limits of the confidence interval of a measured or calculated quantity. NOTE: The probability of the confidence limits should be specified, preferably as two standard deviations.
 

Universal Time (UT)

Family Universal Time (UT) is the general designation of time scales based on the rotation of the Earth. In applications in which a precision of a few tenths of a second cannot be tolerated, it is necessary to specify the form of UT such as UT1 which is directly related to polar motion and is proportional to the rotation of the Earth in space. The UT1 is further corrected empirically for annual and semi-annual variations in the rotation rate of the earth to obtain UT2.
Universal Time is the mean solar time of the prime meridian plus 12 hours, determined by measuring the angular position of the Earth about its axis. The UT is sometimes designated GMT, but this designation should be avoided. Mean Solar Time is simply apparent solar time corrected for the effects of orbital eccentricity and the tilt of the Earth's axis relative to the ecliptic plane; that is, corrected by the equation of time which is defined as the hour angle of the true Sun minus the hour angle of the mean Sun.

us
microsecond
 

USO
Ultra Stable Oscillator
 

UTC
Universal Time Coordinated