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Visar resultat 1 - 5 av 83 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Isolation and chemical modification of arabinoxylan and galactoglucomannan

   Författare :Linda Härdelin; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tg; Films; Material properties; Isolation; Etherification; Modification; PEGylation; Hemicellulose;

   Sammanfattning : Today’s society is based on the use of fossil fuels, where oil is used as transportation fuel and as raw material in the petrochemical industry. Efforts are made to increase the use of bio-based materials, since oil is a non-renewable source and a greenhouse gas contributor. LÄS MER

3. 2. Reproductive isolation at contact zones

   Författare :Samuel Perini; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; hybrid zone; gene flow; genetic variants; mating; local adaptation; marine species; speciation;

   Sammanfattning : Speciation is among the most important evolutionary processes that contribute to biodiversity. It involves the formation of new species that have become reproductively isolated through a process that is not linear and varies in time and space. LÄS MER

4. 3. Discovery of Secondary Metabolites from Rwandese Medicinal Plants : Isolation, Characterization and Biological Activity

   Författare :Daniel Umereweneza; Máté Erdélyi; A Gogoll; Théoneste Muhizi; Yngve Stenstrøm; Uppsala universitet; []
   Nyckelord :Natural products; Nuclear Magnetic Resonance NMR ; Dihydrochalcones; Iridoids; Silphiperfolanols; Pyrrolizidine alkaloids PAs ; Rwandese Medicinal Plants; Chemistry with specialization in Organic Chemistry; Kemi med inriktning mot organisk kemi;

   Sammanfattning : Plants have served as the principal source of medicines in different parts of the world through the ages. Herb-derived medicines have been used as decoctions, infusions, tinctures or single substance drugs. LÄS MER

5. 4. Design, Fabrication and Characterization of GaN HEMTs for Power Switching Applications

   Författare :Björn Hult; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; DCIT; SCE; high voltage; isolation; ‘buffer-free’; gate dielectric; GaN HEMT; passivation; DIBL;

   Sammanfattning : The unique properties of the III-nitride heterostructure, consisting of gallium nitride (GaN), aluminium nitride (AlN) and their ternary compounds (e.g. AlGaN, InAlN), allow for the fabrication of high electron mobility transistors (HEMTs). LÄS MER

7. 5. On Speciation in Birds – Genomic Signatures across Space and Time

   Författare :Martin Stervander; MEMEG; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; colonization; islands; isolation; introgressive hybridization; sympatry; natural selection; bill morphology; coalescence-based analyses; DNA sequencing; birds; divergence; Speciation;

   Sammanfattning : The process of speciation is a cornerstone in evolutionary biology. In Darwin’s On the Origin of Species, he described how he imagined that a new species would evolve to fill an empty niche. This focus on ecology shifted with Mayr towards the importance of isolation, and for many decades the geographic modes of speciation were debated. LÄS MER