Sökning: "frequency"

Visar resultat 1 - 5 av 4764 avhandlingar innehållade ordet frequency.

  1. 1. The Frequency of the Frequency : On Hydropower and Grid Frequency Control

    Författare :Linn Saarinen; Urban Lundin; Per Norrlund; Bengt Carlsson; Kjetil Uhlen; Uppsala universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; hydropower; frequency control; governors; power system stability; inertia; primary control; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : Variations in the electricity consumption and production connected to the power system have to be balanced by active control. Hydropower is the most important balancing resource in the Nordic system, and will become even more important as the share of variable renewable energy sources increases. LÄS MER

  2. 2. Pitch, loudness and frequency selectivity in low-frequency hearing loss

    Författare :Jonas Brännström; Lund näs- och halssjukdomar Öron-; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; frequency coding; Cochlea; frequency selectivity; hearing fluctuation; inner ear pressure; long-term measurement; Ménière s disease; low-frequency hearing loss; loudness; pitch.;

    Sammanfattning : Patients with Ménière's disease and cochlear hydrops show fluctuating low-frequency hearing loss (FLFHL). At present these changes are followed as patients' subjective reports and occasional measurements. LÄS MER

  3. 3. Integration of Non-synchronous Generation - Frequency Dynamics

    Författare :Johan Björnstedt; Industriell elektroteknik och automation; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Frequency control; Frequency dynamics; Frequency response; Non-synchronous generation; Power system; Synthetic inertia; Wind power;

    Sammanfattning : Traditionally the predominant generation has been large synchronous generators providing the system inertia. Nowadays when wind power and other non-synchronously connected units displaces this synchronous generation, the system inertia is reduced. Hence higher rate of change of frequency and larger frequency deviations are expected. LÄS MER

  4. 4. Graphene field-effect transistors for high frequency applications

    Författare :Muhammad Asad; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; high frequency; Graphene; transit frequency; transconductance; maximum frequency of oscillation; contact resistance; microwave electronics; field-effect transistors;

    Sammanfattning : Rapid development of wireless and internet communications requires development of new generation high frequency electronics based on new device concepts and new materials. The very high intrinsic velocity of charge carriers in graphene makes it promising new channel material for high frequency electronics. LÄS MER

  5. 5. Low frequency noise during work. Effects on performance and annoyance

    Författare :Johanna Bengtsson; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Low frequency noise; performance; workload; annoyance; cortisol; subjective stress; subjective sensitivity to noise; sound characteristics; frequency balance; modulation frequency;

    Sammanfattning : Aims. Low frequency noise (LFN) is defined as "a noise with a dominant frequency content of 20 to 200 Hz". Common sources of LFN in occupational environments are ventilation, heating and air-conditioning systems, computer network installations and compressors. LÄS MER