Sökning: "noise work 2012"

Visar resultat 1 - 5 av 40 avhandlingar innehållade orden noise work 2012.

  1. 1. Noise in the preschool : health and preventive measures

    Författare :Fredrik Sjödin; Ulf Landström; Anders Kjellberg; Anders Knutsson; Mats Nilsson; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Noise; hearing disorders; stress; health; occupational environment; preventive measures; intervention; Occupational and Environmental Medicine; arbets- och miljömedicin;

    Sammanfattning : This thesis is based on noise recordings and health evaluations carried out at preschools in the northern part of Sweden. Sound level recordings were made on individuals and by use of stationary devices in dining rooms and play halls. Health evaluations were based on ratings by use of questionnaires and by analyses of cortisol. LÄS MER

  2. 2. GaN HEMT Low Noise Amplifiers for Radio Base Station Receivers

    Författare :Pirooz Chehrenegar; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; gallium nitride GaN ; radio base station receiver; cascode; high linearity; robustness.; cascade; high electron mobility transistor HEMT ; low noise; low noise amplifier;

    Sammanfattning : Gallium nitride (GaN) high electron mobility transistor (HEMT) has been introduced as the technology of choice for high power microwave applications due to its material properties including high saturation electron velocity and breakdown field together with excellent thermal conductivity and robustness.It is also a promising candidate for receiver front-ends in the radio base station(RBS) where low noise figure and high linearity are key issues for low noiseamplifier (LNA) design. LÄS MER

  3. 3. A Segmented Silicon Strip Detector for Photon-Counting Spectral Computed Tomography

    Författare :Cheng Xu; Hans Bornefalk; Mats Danielsson; Ami Altman; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; photon counting; spectral computed tomography; silicon strip detector; ASIC; energy resolution; cadmium telluride; charge sharing; Monte Carlo simulation; synchrotron;

    Sammanfattning : Spectral computed tomography with energy-resolving detectors has a potential to improve the detectability of images and correspondingly reduce the radiation dose to patients by extracting and properly using the energy information in the broad x-ray spectrum. A silicon photon-counting detector has been developed for spectral CT and it has successfully solved the problem of high photon flux in clinical CT applications by adopting the segmented detector structure and operating the detector in edge-on geometry. LÄS MER

  4. 4. Cognitive performance and restoration in open-plan office noise

    Författare :Helena Jahncke; Mats Nilsson; Staffan Hygge; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Teknisk psykologi; Engineering Psychology;

    Sammanfattning : This dissertation presents four experimental studies (in four papers) with the overall aim to investigate the effects of office noise on cognitive performance and restoration. In the first two papers the focus was on the effects of different sound levels (i.e. LÄS MER

  5. 5. Silicon Carbide Bipolar Integrated Circuits for High Temperature Applications

    Författare :Luigia Lanni; Carl-Mikael Zetterling; Niklas Rorsman; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Silicon carbide (SiC) is a semiconductor that provides significant advantages for high-power and high-temperature applications thanks to its wide bandgap, which is several times larger than silicon. The resulting high breakdown field, high thermal conductivity and high intrinsic temperature (well above 600 °C) allow high temperature operation of SiC devices and relaxed cooling requirements. LÄS MER