near field

near field
  1. ближняя зона

 

ближняя зона
зона Френеля

1. Прилегающая к излучателю зона, в которой акустическое поле имеет вид чередующихся между собой максимумов и минимумов, ограниченная расположением последнего максимума, после которого происходит монотонное уменьшение амплитуды с расстоянием. Протяженность ближней зоны круглого пьезоэлемента
4710
где D - диаметр пьезоэлемента;
λ – длина волны
2. Зона, в которой вследствие интерференции звуковое давление не меняется монотонно с расстоянием. Эта зона ограничена последним максимумом звукового давления на оси пучка
[BS EN 1330-4:2000. Non-destructive testing - Terminology - Part 4: Terms used in ultrasonic testing]
4709
Рис. 6. Параметры акустического пучка:
1 - излучатель; 2 - граница пучка; 3 - акустическая ось пучка; 4 - дальняя зона; rб - протяженность ближней зоны; θ - угол расхождения пучка
[Система неразрушающего контроля. Виды (методы) и технология неразрушающего контроля. Термины и определения (справочное пособие). Москва 2003 г.]

Тематики

  • виды (методы) и технология неразр. контроля

Синонимы

  • зона Френеля

EN

  • Fresnel-zone
  • near field


Англо-русский словарь нормативно-технической терминологии. . 2015.

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Смотреть что такое "near field" в других словарях:

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