Sökning: "spectral characteristics"

Visar resultat 1 - 5 av 149 avhandlingar innehållade orden spectral characteristics.

  1. 1. The spectral reflectance of coniferous tree stands and of barley influenced by stress : an analysis of field measured spectral data

    Författare :Johan Kleman; Stockholms universitet; []
    Nyckelord :spectral reflectance; field measurement; middle infrared; crops; fertilisation; irrigation; coniferous forest; helicopter; measuring geometry;

    Sammanfattning : This thesis focuses on the spectral signatures for vegetation. Knowledge about the spectral characteristics of different vegetation types is imperative for an efficient use of existing remote sensing systems, and also to provide guidelines for sensor development. LÄS MER

  3. 2. Spectral analysis in laser powder bed fusion

    Författare :Benedikt Brandau; Frank Brückner; Alexander Kaplan; Dan Roth-Fagaraseanu; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spectral monitoring; Laser powder bed fusion; Laser optics; Absorbance; Produktionsutveckling; Manufacturing Systems Engineering;

    Sammanfattning : This thesis is about the investigation of the spectral interaction of electromagnetic radiation with metal powders. For this purpose, spectral data of powders for laser powder bed fusion processes are investigated in three papers using different techniques. LÄS MER

  4. 3. Fine-scale morphology and spectral characteristics of active aurora

    Författare :Hanna Dahlgren; Göran Marklund; Nickolay Ivchenko; Kari Kaila; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Aurora; Space physics; Rymdfysik;

    Sammanfattning : Ground-based and in-situ observations of the aurora demonstrate an extreme richness in fine structure, with spatial scales down to tens of metres and time variations occurring on a fraction of a second. To further our understanding of the aurora, it is esssential to understand the mechanisms responsible for the small-scale structuring, since this is an intrinsic property of the auroral plasma. LÄS MER

  5. 4. Fundamental Studies on Direct Injection Nebulisers for Sample Introduction in ICP Spectrometry : Aerosol Properties, ICP Characteristics and Analytical Performance

    Författare :Daniel Goitom Asfaha; Wolfgang Frech; Ralph Edward Sturgeon; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ICP; ICP-MS; ICP-OES; sample introduction; DIHEN; Vulkan DIN; non-spectral interferences; noise power spectra; analytical precision; plasma diagnostic parameters; particle dynamic analysis PDA ; Analytical chemistry; Analytisk kemi;

    Sammanfattning : The performance of different types of nebulisers: Vulkan direct injection nebuliser (Vulkan DIN), direct injection high efficiency nebuliser (DIHEN), microconcentric nebuliser coupled to cyclonic or double pass spray chamber (MCN-C or MCN-DP, respectively) was investigated and compared when used for sample introduction to ICP-MS or ICP-OES. With ICP-OES, in axial viewing mode, intensity distributions across the radius of the plasma (radial intensity profiles) were determined for different spectral lines with Esum 1. LÄS MER

  7. 5. Remote Sensing of Forest Decline in the Czech Republic

    Författare :Jonas Ardö; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Czech Republic; neural networks; sulphur dioxide; air pollution; Norway spruce; deforestation; forest decline; GIS; spectral characteristics; Remote sensing; Landsat; Ore Mountains; Geology; physical geography; Geologi; fysisk geografi;

    Sammanfattning : This thesis describes the localisation and quantification of deforestation and forest damage in Norway spruce forests in northern Czech Republic using Landsat data. Severe defoliation increases the spectral reflectance in all wavelength bands, especially in the mid infrared region. LÄS MER