Sökning: "Deuterium"

Visar resultat 1 - 5 av 142 avhandlingar innehållade ordet Deuterium.

1. 1. Deuterium isotopomers as a tool in environmental research

   Författare :Tatiana Betson; Jürgen Schleucher; Peter Högberg; Richard Robins; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; deuterium; NMR; isotopomers; CO2 response; climate reconstruction; persistent pollutants; stable isotopes; Environmental chemistry; Miljökemi;

   Sammanfattning : This thesis describes the development and the use of quantitative deuterium Nuclear Magnetic Resonance spectroscopy (NMR) as a tool in two areas of environmental research: the study of long term climate-plant interactions and the source tracking of persistent organic pollutant. Long-term interactions between plants and climate will influence climate change during this century and beyond, but cannot be studied in manipulative experiments. LÄS MER

3. 2. Monitoring climate and plant physiology using deuterium isotopomers of carbohydrates

   Författare :Angela Augusti; Jürgen Schleucher; Vaughan Hurry; Howard Griffiths; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Climate reconstruction; deuterium; elevated CO2; isotopomer; nuclear magnetic resonance; photorespiration; tree-ring cellulose.; Plant physiology; Växtfysiologi;

   Sammanfattning : Climate is changing and it is certain that this change is due to human activities. Atmospheric greenhouse gases have been rising in an unprecedented way during the last two centuries, although the land biosphere has dampened their increase by absorbing CO2 emitted by anthropogenic activities. LÄS MER

4. 3. Water Relaxation Processes as Seen by NMR Spectroscopy Using MD and BD Simulations

   Författare :Ken Åman; Per-Olof Westlund; Arnold Maliniak; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; NMR; Stochastic Liouville Equation; Brownian Dynamics; Molecular Dynamics; Water; Relaxation; Deuterium; ESR; Fysikalisk kemi; Physical chemistry; Fysikalisk kemi; Physical Chemistry; fysikalisk kemi;

   Sammanfattning : This thesis describes water proton and deuterium relaxation processes, as seen by Nuclear Magnetic Resonance (NMR) spectroscopy, using Brownian Dynamics (BD) or Molecular Dynamics (MD) simulations. The MD simulations reveal new detailed information about the dynamics and order of water molecules outside of a lipid bilayer. LÄS MER

5. 4. Ion Beam Analysis of First Wall Materials Exposed to Plasma in Fusion Devices

   Författare :Per Petersson; Göran Possnert; Anders Hallén; Marek Rubel; Eduardo C. Alves; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ion beam analysis; Microbeam; Plasma wall interaction; Deuterium; Beryllium; Carbon fibre composites; Divertor; Nuclear reaction analysis; Helium-3; Plasma physics with fusion; Plasmafysik med fusion; Ion Physics; Jonfysik;

   Sammanfattning : One major step needed for fusion to become a reliable energy source is the development of materials for the extreme conditions (high temperature, radioactivity and erosion) caused by hot plasmas. The main goal of the present study is to use and optimise ion beam methods (lateral resolution and sensitivity) to characterise the distribution of hydrogen isotopes that act as fuel. LÄS MER

7. 5. Alternative methods for analysing moisture transport in buildings : Utilisation of tracer gas and natural stable isotopes

   Författare :Kjartan Gudmundsson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tracer gas; water vapour permeability; diffusion; surface diffusion; isotopic analysis; deuterium; oxygen-18; fractionation; vapour barrier; transient numerical modelling of diffusion; Building engineering; Byggnadsteknik;

   Sammanfattning : New methods, based on tracer gas measurements and isotopicanalysis can be used to evaluate the moisture properties ofbuilding materials and provide the means for forensic analysisof the origins and history of excessive water in buildings, theimmediate practical consequences of which will be the abilityto improve the moisture performance of constructions. It is shown, in theory and through measurements how thewater vapour permeability of porous building materials can witha good degree of accuracy be estimated with tracer gasmeasurements that provide an efficient alternative to the cupmethod. LÄS MER