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Eng ID | Term | Definition |
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3781 | permeability: magnetic | See MAGNETIC PERMEABILITY. |
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3782 | personal correction | The CORRECTION due to PERSONAL ERROR. |
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3783 | personal equation | The time interval between the sensory perception of a PHENOMENON and the motor reaction thereto. Personal equation may be either positive o... more |
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3784 | personal error | See ERROR. |
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3785 | personal parallax | See PARALLAX: INSTRUMENTAL. |
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3786 | perspective centre | The point of origin or termination of bundles of PERSPECTIVE RAYS. The two such points usually associated with a survey photograph are the ... more |
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3787 | perspective grid | See GRID. |
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3788 | perspective plane | Any plane containing the PERSPECTIVE CENTRE. The intersection of a perspective plane and the GROUND will always appear as a straight line o... more |
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3789 | perspective projection | See PROJECTION. |
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3790 | perspective ray | A line joining a PERSPECTIVE CENTRE and a point object. |
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3791 | perturbation | Disturbance in the orbital PATH of a CELESTIAL BODY, natural or artificial, due to attraction of another body. See LUNAR INEQUALITY. |
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3792 | Ph | A SCALE used for expressing the acidity or ALKALINITY of solutions. |
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3793 | phantom bottom | A false BOTTOM indicated by an ECHO SOUNDER, some distance above the actual BOTTOM. Such an indication, quite common in the deeper parts of ... more |
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3794 | phase | The visible aspect of an object. The amount by which a CYCLE has progressed from a specified origin. In ASTRONOMY, any of the stages of vari... more |
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3795 | phase angle | The phase difference of two periodically recurring PHENOMENA of the same FREQUENCY, expressed in angular measure. The angle at a CELESTIAL ... more |
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3796 | phase inequality | Variations in the TIDES or TIDAL CURRENTS associated with changes in the PHASE OF THE MOON. |
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3797 | phase lag | Angular retardation of the maximum of a constituent of the observed TIDE behind the corresponding maximum of the same constituent of the ... more |
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3798 | phase modulation | See MODULATION. |
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3799 | phase of a navigational light | A visually discrete part of a light signal. It is bounded by changes between darkness and light (e.g. an occultation or flash), or between d... more |
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3800 | phase(s) of the moon | The various appearances of the MOON during different parts of the SYNODICAL MONTH. The CYCLE begins with new moon or change of the MOON at C... more |