Sökning: "trace species detection"

Visar resultat 1 - 5 av 15 avhandlingar innehållade orden trace species detection.

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

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

    Sammanfattning : 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. LÄS MER

  3. 2. Liquid Membrane Techniques for Trace Metal Analysis and Speciation in Environmental and Biological Matrices

    Författare :Kuria Ndung'u; Centrum för analys och syntes; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Analytical chemistry; Pb and Organotin species; MMLLE; SLM; GC MS; PSA; GFAS; FAAS; ICP-MS; Speciation; DEHPA; Aliquat-336; trace metals; Cr III ; Cr VI ; Analytisk kemi;

    Sammanfattning : In this thesis, liquid-membrane-based methods for the analysis of trace metal species in samples of environmental and biological origin were developed. By incorporating extracting reagents in the membrane liquid, trace metal ions were selectively separated from humic-rich natural waters and urine samples, prior to their determination using various instrumental techniques. LÄS MER

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

    Författare :Aleksandra Foltynowicz; Ove Axner; Weidong Chen; Umeå universitet; []
    Nyckelord :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;

    Sammanfattning : 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). LÄS MER

  5. 4. Mid-infrared photonic devices for on-chip optical gas sensing

    Författare :Floria Ottonello Briano; Kristinn B. Gylfason; Delphine Marris-Morini; 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; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; mid-infrared; mid-IR; photonics; silicon photonics; gas sensing; optical sensing; optical gas sensing; spectroscopy; absorption; dispersion; carbon dioxide; CO2; CO2 sensing; trace gas; ethanol sensing; alcohol sensing; waveguide; photonic waveguide; ring resonator; nanowire; nanoheater; emitter; thermal source; bolometer; microbolometer; thermal detector; high frequency; 3 omega method; plasmonic; platinum; Kanthal; silicon-on-insulator; micro-electro-mechanical systems MEMS ; microfabrication; microsystems; microtechnology; nanotechnology; Optik och fotonik; Optics and Photonics; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Gas detection is crucial in a wide range of fields and applications, such as safety and process control in the industry, atmospheric sciences, and breath diagnostics. Optical gas sensing offers some key advantages, compared to other sensing methods such as electrochemical and semiconductor sensing: high specificity, fast response, and minimal drift. LÄS MER

  7. 5. Biochip design based on tailored ethylene glycols

    Författare :Andréas Larsson (Kaiser); Bo Liedberg; Tommy Nylander; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biosensor; biochip; poly ethylene glycol ; self-assembled monolayer; photopolymerisation; microarray; biomolecular interaction; explosives detection; Physics; Fysik;

    Sammanfattning : Studies of biomolecular interactions are of interest for several reasons. Beside basic research, the knowledge gained from such studies is also very valuable in for example drug target identification. Medical care is another area where biomolecules may be used as biomarkers to aid physicians in making correct diagnosis. LÄS MER