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  2. Internal focusing - Wikipedia

    en.wikipedia.org/wiki/Internal_focusing

    During macro photography, using an internal focus lens reduces the risk of the front of the lens accidentally hitting the subject during focusing as the front element does not move. [1] The physical size of an internal focusing lens does not change during focus, nor does the front of the lens rotate.

  3. Ectopic pacemaker - Wikipedia

    en.wikipedia.org/wiki/Ectopic_pacemaker

    An ectopic pacemaker, also known as ectopic focus or ectopic foci, is an excitable group of cells that causes a premature heart beat outside the normally functioning SA node of the heart. It is thus a cardiac pacemaker that is ectopic , producing an ectopic beat .

  4. Internal ballistics - Wikipedia

    en.wikipedia.org/wiki/Internal_ballistics

    Internal ballistics (also interior ballistics), a subfield of ballistics, is the study of the propulsion of a projectile.. In guns, internal ballistics covers the time from the propellant's ignition until the projectile exits the gun barrel. [1]

  5. Photoreceptor cell - Wikipedia

    en.wikipedia.org/wiki/Photoreceptor_cell

    Farther back still is the inner segment, a specialized part of the cell full of mitochondria. The chief function of the inner segment is to provide ATP (energy) for the sodium-potassium pump. Finally, closest to the brain (and farthest from the field of view) is the outer segment, the part of the photoreceptor that absorbs light.

  6. Adjustable-focus eyeglasses - Wikipedia

    en.wikipedia.org/wiki/Adjustable-focus_eyeglasses

    Adjustable focus lenses, like single-focus lenses, also reduce image-jump and spatial distortion in the field of view associated with traditional multi-focal lenses. Additionally, the ideal near-vision correction can be achieved with precision, because the variable lenses emulate the focusing action of the youthful (non-presbyopic) eye.

  7. Coherent anti-Stokes Raman spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Coherent_anti-Stokes_Raman...

    The comparison should only be used as an indication of the order of magnitude of the signals. 200 mW average power input (CW for the Raman), in a 0.9NA objective with a center wavelength around 800 nm, constitutes a power density of 26 MW/cm, 2 (focus length = 1.5 micrometre, focus volume = 1.16 micrometre 3, photon energy = 2.31×10 −19 J or ...

  8. Ground proximity warning system - Wikipedia

    en.wikipedia.org/wiki/Ground_proximity_warning...

    If there is a dramatic change in terrain, such as a steep slope, GPWS will not detect the aircraft closure rate until it is too late for evasive action. In the late 1990s, improvements were developed and the system is now named "Enhanced Ground Proximity Warning System" (EGPWS/TAWS).

  9. Automatic tachycardia - Wikipedia

    en.wikipedia.org/wiki/Automatic_tachycardia

    An automatic tachycardia is a cardiac arrhythmia which involves an area of the heart generating an abnormally fast rhythm, sometimes also called enhanced automaticity. These tachycardias , or fast heart rhythms, differ from reentrant tachycardias ( AVRT and AVNRT ) in which there is an abnormal electrical pathway which gives rise to the pathology.