Search results

Filter

Filetype

Your search for "*" yielded 533537 hits

IInterpretation of Anomalous Ultraviolet Transitions of Fe II Observed in Laboratory Fourier Transform Spectra and Stellar HST and IUE Spectra

We discuss LS-forbidden Delta S = 2 transitions of Fe Pi that appear as strong lines in ultraviolet stellar and laboratory spectra. The lines occur because of indirect lever mixing-two close energy levels, w(2)P(3/2) and x(6)P(3/2), are mixed through a third level acting as a catalyst. In transition multiplets, that involve either the w(2)P(3/2) or the x(6)P(3/2) level the normal component is acco

Interactions between Sulfide Minerals and Alkylxanthate Ions .5. A Vibration Spectroscopic Study of the Interactions between Chalcocite, Synthetic Copper(I) Sulfide, Acanthite and Synthetic Silver(I) Sulfide, and Ethylxanthate Ions in Aqueous and Acetone Solutions

The reactions between chalcocite, synthetic copper(I) sulfide, acanthite and synthetic silver(I) sulfide, and aqueous and acetone solutions of potassium ethylxanthate have been studied. Qualitative analysis of the ethylxanthate species present on the surfaces of the sulfide minerals and the synthetic metal sulfides has been made by means of diffuse reflectance infrared Fourier transform (DRIFT) sp

Fertilitetsbevarande kirurgi vid livmoderhalscancer nu möjlig

This article describes the first Swedish experience with fertility preserving surgery according to the technique of Dargent. Minimally invasive methods gain acceptance in the treatment of other tumours and this method seems to treat adequately and preserve function. The literature is reviewed and discussed. In Sweden about 25-40 women under 30 years of age are each year diagnosed with cancer of th

Singular Ginzburg-Landau Vortices

In this thesis we study the critical Ginzburg-Landau action, defined on fields in the plane which are allowed to have a finite number of singularities. We show that a topological invariant, the degree, can be defined under the assumption of finite action only. The action is bounded below by a constant times the degree, and the fields which realize this lower bound satisfy a first order differentia

Electroanalytical study of Prussian Blue modified glassy carbon paste electrodes

Two types of glassy carbon (GC) powder (i.e., Sigradur K and Sigradur G) have been mixed with mineral oil to obtain glassy carbon paste electrodes (GCPE's). The electrochemical behavior of such electrodes at different percentages of glassy carbon has been evaluated with respect to the electrochemistry of ferricyanide as revealed with cyclic voltammetry and the best paste composition was chosen. GC

Some Extensions of Poincaré-Bendixson Theory Applied to a Resonant Converter.

Popular Abstract in Swedish I denna avhandling studeras en resonant omvandlare. Detta är en elektrisk krets som amvandlar likspänningar från en nivå till en annan. För att styra detta system, måste man förstå dess egenskaper. Min uppgift har varit att undersöka huruvida systemet innehåller s.k. gränscykler (självsvängningar) respektive chattering (extremt snabba självsvängningar). Vissa av dessa gIn this thesis existence and uniqueness of limit cycles are shown for a resonant converter, by extending Poincaré-Bendixson theory to non-smooth vector fields. We discuss relevant control theory and the role of simulations.

Greening Earth? Science, Politics and Land Use in the Kyoto Negotiations

Can a deliberate enhancement of the natural uptake of atmospheric carbon dioxide in forests and agricultural lands contribute to the efforts to mitigation anthropogenic climate change? This is a question that has generated a great deal of debate and controversy since the inception of the multilateral climate negotiations in the early 1990s. This thesis offers an analysis of how this debate has pla

Extracting Syringe for determination of organochlorine pesticides in leachate water and soil-water slurry: A novel technology for environmental analysis

The Extracting Syringe (ESy), a novel membrane-based sample preparation technique directly coupled as an autosampler to gas chromatography, has been employed for the analysis of organochlorine pesticides (OCPs) in raw leachate water. The ESy has also been applied for extraction of OCPs from contaminated soil samples and its performance has been compared to liquid-solid extraction (LSE) and acceler

Artefactual Intelligence: The Development and Use of Cognitively Congenial Artefacts

How can tools help structure tasks to make them cognitively easier to perform? How do artefacts, and our strategies for using them, develop over time in cognitively beneficial ways? These are two of the main questions that are explored in the five papers collected in this thesis. The first paper details an ethnographic study conducted on people cooking in their homes. The study is a first pass ov

Charge Sampling Circuits and A/D Converters - Theory and Experiments

The analysis of general charge sampling technique is presented in this thesis. Charge sampling integrates input current instead of tracking input voltage to realize high speed and low voltage sampling. The analysis focuses on the performance of general charge sampling circuits for signal capture. The theoretical analysis here can be applied not only for the weak signal capture, but also for the no

Comparison of xylose fermentation by Saccharomyces cerevisiae strains carrying either xylose reductase and xylitol dehydrogenase or xylose isomerase

Background: Two heterologous pathways have been used to construct recombinant xylose-fermenting Saccharomyces cerevisiae strains: i) the xylose reductase ( XR) and xylitol dehydrogenase (XDH) pathway and ii) the xylose isomerase (XI) pathway. In the present study, the Pichia stipitis XR-XDH pathway and the Piromyces XI pathway were compared in an isogenic strain background, using a laboratory host

Occurrence and degradation of peptidoglycan in aquatic environments

Mechanisms controlling microbial degradation of dissolved organic matter (DOM) in aquatic environments are poorly understood, although microbes are crucial to global nutrient cycling. Bacterial cell wall components may be one of the keys in understanding the presence of slowly degrading DOM in nature. We found that dominant components of bacterial cell walls (D-amino acids (D-AA), glucosamine (Glu