enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Everhart–Thornley detector - Wikipedia

    en.wikipedia.org/wiki/Everhart–Thornley_detector

    The E-T secondary electron detector can be used in the SEM's back-scattered electron mode by either turning off the Faraday cage or by applying a negative voltage to the Faraday cage. However, better back-scattered electron images come from dedicated BSE detectors rather than from using the E–T detector as a BSE detector.

  3. Discover the latest breaking news in the U.S. and around the world — politics, weather, entertainment, lifestyle, finance, sports and much more.

  4. Elevator - Wikipedia

    en.wikipedia.org/wiki/Elevator

    Dual door open and door close buttons, in an elevator with two sets of doors, found on a ThyssenKrupp elevator from the 2010s In case of dual doors, there may be two sets of door open and door close buttons, with one pair controlling the front doors, from the perspective of the console, typically denoted <> and ><, with the other pair ...

  5. Metal detector - Wikipedia

    en.wikipedia.org/wiki/Metal_detector

    U.S. Army soldiers use a military standard metal detector. A metal detector is an instrument that detects the nearby presence of metal. Metal detectors are useful for finding metal objects on the surface, underground, and under water. A metal detector consists of a control box, an adjustable shaft [dubious – discuss], and a variable-shaped ...

  6. Automatic door - Wikipedia

    en.wikipedia.org/wiki/Automatic_door

    The automatic door used a mat actuator. In 1960, they co-founded Horton Automatics Inc and placed the first commercial automatic sliding door on the market. [5] With the invention of the Gunn diode, microwave motion detectors became common in automatic doors in the 1970s. [6] [7] In 1980, the first automatic door using an infrared sensor was ...

  7. Passive infrared sensor - Wikipedia

    en.wikipedia.org/wiki/Passive_infrared_sensor

    As a result of the focussing, the detector view is actually a beam pattern. Under certain angles (zones), the PIR sensor receives almost no radiation energy and under other angles the PIR receives concentrated amounts of infrared energy. This separation helps the motion detector to discriminate between field-wide illumination and moving objects.

  8. Explosives trace detector - Wikipedia

    en.wikipedia.org/wiki/Explosives_trace_detector

    Detection limit is defined as the lowest amount of explosive matter a detector can detect reliably. It is expressed in terms of nano-grams (ng), pico-grams (pg) or femto-grams (fg) with fg being better than pg better than ng. It can also be expressed in terms of parts per billion (ppb), parts per trillion (ppt) or parts per quadrillion (ppq).

  9. Electromagnetic lock - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_lock

    These door holders were traditionally used to hold doors open, but in this application Saphirstein believed that they could be packaged and adapted to work as a fail-safe lock. After a successful prototype and installation at the Forum, Saphirstein continued evolving and improving the design and established the Locknetics company to develop ...