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Visar resultat 1 - 5 av 284 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Inductively Coupled Plasma Atomic Emission Spectrometry : Exploring the Limits of Different Sample Preparation Strategies

    Författare :Barbro Kollander; Jean Pettersson; Marit Andersson; Jonas Bergquist; Grethe Wibetoe; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; multi element analysis; trace element; ICP-AES; inductively coupled plasma atomic emission spectromtery; water analysis; liver analysis; non digested samples; medical samples; biological samples; samples from biopsies and autopsies; mice organ; fast analysis; internal standard; preconcentration; matrix elimination; Cu; Zn; Mn; Co; Pb; Cd; Mg; Ca; Fe; Ni; Cr; S; P; K; Al; Analytical chemistry; Analytisk kemi; Analytical Chemistry; Analytisk kemi;

    Sammanfattning : This thesis describes two different sample preparation strategies for inductively coupled plasma atomic emission spectrometry (ICP-AES), and their ability regarding multi element quantification in complex samples. Sensitivity, repeatability, reproducibility and accuracy were investigated. LÄS MER

  3. 2. Improved methods for enrichment of organic ultra trace components for analysis by gas chromatography

    Författare :Adam Kloskowski; KTH; []
    Nyckelord :water analysis; gas analysis; environmental analysis; sorbent trapping; organic traces; SPME; OTT;

    Sammanfattning : This thesis describes some new methods for analysis oforganic trace components from air and water by gaschromatography. The work is particularly focused on thedevelopment of new technologies for analyte enrichment, usingsorbent-based concepts. Short lengths of open tubular columnswere examined for their potential use as denuders. LÄS MER

  4. 3. Resonances of Dirac Operators

    Författare :Jimmy Kungsman; Wolfgang Staubach; Roman Schubert; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Semiclassical analysis; Dirac operator; resonances; Poisson trace formula; scattering theory; complex absorbing potential; pseudodifferential operator; Mathematics; Matematik;

    Sammanfattning : This thesis consists of a summary of four papers dealing with resonances of Dirac operators on Euclidean 3-space. In Paper I we show that the Complex Absorbing Potential (CAP) method is valid in the semiclassical limit for resonances sufficiently close to the real line if the potential is smooth and compactly supported. LÄS MER

  5. 4. Laser-Based Combustion and Trace-element Analysis

    Författare :Yvonne Malmsten; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; laser-induced fluorescence; graphite furnace; trace element analysis; LEI; laser-enhanced ionisation; LIF; meta-stable; flow-tagging; NO; OH; counter-flow diffusion flame;

    Sammanfattning : Laser spectroscopy has been utilised as a tool for combustion diagnostics and sensitive trace-element analysis. In the field of combustion analysis, a characterisation of a CH4/N2 - O2/N2 counter-flow diffusion flame has been performed using Laser-Induced Fluorescence (LIF). LÄS MER

  7. 5. Extremal eigenvalues and geometry of quantum graphs

    Författare :Andrea Serio; Pavel Kurasov; Annemarie Luger; Evans Harrell; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum graphs; spectral estimates; trace formula; Euler characteristic; Mathematics; matematik;

    Sammanfattning : This thesis consists of four papers concerning topics in the spectral theory of quantum graphs, which are differential operators on metric graphs.In paper I we present a family of graphs with an arbitrary number of cycles for which a certain eigenvalue upper estimate is sharp. LÄS MER