Search for dissertations about: "built-in electric field"

Found 3 swedish dissertations containing the words built-in electric field.

  2. 1. Localization effects in ternary nitride semiconductors

    Author : Vytautas Liuolia; Saulius Marcinkevicius; Toshiharu Saiki; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; AlGaN; InGaN; AlInN; LEDs; near-field microscopy; carrier dynamics; alloy fluctuations; carrier localization; built-in electric field; nonpolar planes; polarized luminescence;

    Abstract : InGaN based blue and near-ultraviolet light emitting diodes and laser diodes have been successfully commercialized for many applications such as general lighting, display backlighting and high density optical storage devices. Despite having a comparably high defect density, these devices are known for their efficient operation, which is attributed to localization in potential fluctuations preventing carriers from reaching the centers of nonradiative recombination. READ MORE

  4. 2. Differential Protection for Arbitrary Three-Phase Power Transformers

    Author : Zoran Gajic; Industriell elektroteknik och automation; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electric power systems; power transformers; differential protection; power system protection;

    Abstract : This thesis describes how to provide standardized, current based, differential protection for any three-phase power transformer, including phase-shifting transformers with variable phase angle shift and transformers of all construction types and internal on-load tap-changer configurations. The use of standard transformer differential protection for such applications is considered impossible in the protective relaying standards and practices currently applied. READ MORE

  5. 3. The Effects of Lightning on Low Voltage Power Networks

    Author : Raul Montaño; Vernon Cooray; Marcos Rubinstein; Uppsala universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Lightning induced effects; Lightning Electromagnetic fields; Electromagnetic Compatibility EMC ; Surge Protective Devices SPDs ; Low voltage power networks; Elektroteknik; elektronik och fotonik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Abstract : The present society is highly dependant on complex electronics systems, which have a low damage threshold level. Therefore, there is a high risk of partial or total loss of the system’s electronics when they are exposed to a thunderstorm environment. READ MORE