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  2. Optical brightener - Wikipedia

    en.wikipedia.org/wiki/Optical_brightener

    Optical brighteners, optical brightening agents ( OBAs ), fluorescent brightening agents ( FBAs ), or fluorescent whitening agents ( FWAs ), are chemical compounds that absorb light in the ultraviolet and violet region (usually 340-370 nm) of the electromagnetic spectrum, and re-emit light in the blue region (typically 420-470 nm) through the ...

  3. Relativistic beaming - Wikipedia

    en.wikipedia.org/wiki/Relativistic_beaming

    In physics, relativistic beaming (also known as Doppler beaming, Doppler boosting, or the headlight effect) is the process by which relativistic effects modify the apparent luminosity of emitting matter that is moving at speeds close to the speed of light. In an astronomical context, relativistic beaming commonly occurs in two oppositely ...

  4. Contrast (vision) - Wikipedia

    en.wikipedia.org/wiki/Contrast_(vision)

    Contrast (vision) Six renditions of a rocky shore photo with incremental contrast levels, clockwise from bottom left. Contrast is the difference in luminance or color that makes an object (or its representation in an image or display) visible against a background of different luminance or color. The human visual system is more sensitive to ...

  5. Cosmic distance ladder - Wikipedia

    en.wikipedia.org/wiki/Cosmic_distance_ladder

    Dashed black lines: Uncertain calibration ladder step. The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A direct distance measurement of an astronomical object is possible only for those objects that are "close enough ...

  6. Boost converter - Wikipedia

    en.wikipedia.org/wiki/Boost_converter

    A boost converter or step-up converter is a DC-to-DC converter that increases voltage, while decreasing current, from its input to its output . It is a class of switched-mode power supply (SMPS) containing at least two semiconductors, a diode and a transistor , and at least one energy storage element: a capacitor , inductor , or the two in ...

  7. Luminous flux - Wikipedia

    en.wikipedia.org/wiki/Luminous_flux

    The luminous flux is a weighted sum of the power at all wavelengths in the visible band. Light outside the visible band does not contribute. The ratio of the total luminous flux to the radiant flux is called the luminous efficacy. This model of the human visual brightness perception, is standardized by the CIE and ISO. [5]

  8. Brightness - Wikipedia

    en.wikipedia.org/wiki/Brightness

    Brightness is a subjective sensation of an object being observed and one of the color appearance parameters of many color appearance models, typically denoted as . Brightness refers to how much light appears to shine from something. This is a different perception than lightness, which is how light something appears compared to a similarly lit ...

  9. The 13 Best Serums for Oily Skin - AOL

    www.aol.com/12-best-serums-oily-skin-155700551.html

    This water-based niacinamide and zinc serum works for just about any skin type and aims to boost brightness and smoothness while strengthening the skin's barrier at the same time.