Search for dissertations about: "Absorption Spectrometry AS"

Showing result 1 - 5 of 53 swedish dissertations containing the words Absorption Spectrometry AS.

  2. 1. Laser-based absorption spectrometry : development of NICE-OHMS towards ultra-sensitive trace species detection

    Author : Florian Schmidt; Ove Axner; Livio Gianfrani; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; absorption spectrometry; trace species detection; fiber laser; modulation; cavity-enhanced spectroscopy; optical saturation; laser frequency stabilization; free-spectral-range; Physics; Fysik;

    Abstract : Laser-based absorption spectroscopy (AS) is a powerful technique for qualitative and quantitative studies of atoms and molecules. An important field of use of AS is the detection of species in trace concentrations, which has applications not only in physics and chemistry but also in biology and medicine, encompassing environmental monitoring, regulation of industrial processes and breath analysis. READ MORE

  4. 2. Development of diode laser-based absorption and dispersion spectroscopic techniques for sensitive and selective detection of gaseous species and temperature

    Author : Lemthong Lathdavong; Ove Axner; Jürgen Röpcke; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Absorption Spectrometry AS ; Wavelengh Modulation Absorption Spectrometry WMAS ; Faraday Modulation Spectrometry FAMOS ; Tunable Diode Laser Absorption Spectrometry TDLAS ; Optics; Optik; fysik; Physics;

    Abstract : The main aim of this thesis has been to contribute to the ongoing work with development of new diode-laser-based spectroscopic techniques and metho­do­lo­gies for sensitive detection of molecules in gas phase. The techniques under scrutiny are tunable diode laser absorption spectrometry (TDLAS) and Faraday modulation spectrometry (FAMOS). READ MORE

  5. 3. Fiber-laser-based noise-immune cavity-enhanced optical heterodyne molecular spectrometry

    Author : Aleksandra Foltynowicz; Ove Axner; Weidong Chen; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; absorption spectrometry; frequency modulation; cavity enhancement; NICE-OHMS; Laser frequency stabilization; fiber laser; Fabry-Perot cavities; sub-Doppler spectroscopy; trace gas detection; Physics; Fysik; Molecular physics; Molekylfysik; fysik; Physics;

    Abstract : Noise-immune cavity-enhanced optical heterodyne molecular spectro-metry (NICE-OHMS) is one of the most sensitive laser-based absorption techniques. The high sensitivity of NICE-OHMS is obtained by a unique combination of cavity enhancement (for increased interaction length with a sample) with frequency modulation spectrometry (for reduction of noise). READ MORE

  6. 4. Speciation analysis of butyl- and phenyltin compounds in environmental samples by GC separation and atomic spectrometric detection

    Author : Dong Nguyen Van; Wolfgang Frech; Anders Cedergren; Erwin Rosenberg; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Organotin speciation analysis; species-specific isotope dilution; inductively coupled plasma mass spectrometry; single isotope spike; multi-isotope spike; redistribution; species transformation; preparative liquid chromatography; gas chromatography; line source atomic absorption spectrometry; continuum source atomic absorption spectrometry; Analytical chemistry; Analytisk kemi;

    Abstract : The main goal of the work presented in this thesis is to improve the reliability of existing methods for speciation analysis of organotin compounds Species-specific isotope dilution (SSID) calibration in combination with gas chromatography – inductively coupled plasma mass spectrometry was used to investigate the transformation of phenyltin species during sample preparation. Isotope-enriched phenyltin species were synthesized from corresponding isotope-enriched tin metals. READ MORE

  7. 5. Cavity enhanced optical sensing

    Author : Isak Silander; Ove Axner; Aleksandra Foltynowicz; Jong Chow; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Optical resonators; Fiber Laser; Parametric oscillators; Optical frequency comb; Infrared; Spectroscopy heterodyne; Spectroscopy molecular; Absorption; Dispersion; Lineshapes; Optical standards and testing; Refractivety measurements;

    Abstract : An optical cavity comprises a set of mirrors between which light can be reflected a number of times. The selectivity and stability of optical cavities make them extremely useful as frequency references or discri­mi­nators. READ MORE