Sökning: "pine"

Visar resultat 11 - 15 av 279 avhandlingar innehållade ordet pine.

  1. 11. Natural products from nonracemie building blocks : synthesis of pine sawfly pheromones

    Författare :Michael Larsson; Torbjörn Norin; Gunnar Westman; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; Total synthesis; diastereoselective addition; dimethylzinc; Lewis acid; alkyllithium; Organisk kemi; Organic chemistry; Organisk kemi;

    Sammanfattning : This thesis describes a number of synthetic approaches for obtaining chiral, enantiomerically pure natural products, in particular some semiochemicals. This has been accomplished by using various strategies; by starting from compounds from the chiral pool, by using chiral auxiliaries, via enzymatic resolutions or by chemical asymmetric synthesis. LÄS MER

  3. 12. Adhesion to machined and laser ablated wood surfaces

    Författare :Micael Stehr; KTH; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; ablation; adhesion; checks; coating; cracks; excimer laser; gluing; IR laser; mechanical machining; mechanical weak boundary layer; microscopy; notched specimens; pine; planing; sample preparation; sawing; scanning electronmicroscopy; spruce; tip-cracks; UV laser; weak boundary layer; wood;

    Sammanfattning : This thesis is a contribution to the R&D-program ValueActivation at KTH,Division of Wood Technology and Processingand containsfive papers related to the evaluation and development ofmachining techniques (mechanical and irradiation treatments)whereby weak boundaries at the wood surfaces in the form of(mechanical) weak boundary layers and (micro) cracks due tomechanical treatment can be avoided.The first paper describes the development of a method–using a UV laser–to study the mechanically weakenedboundaries. LÄS MER

  4. 13. How could Christmas trees remain evergreen? : photosynthetic acclimation of Scots pine and Norway spruce needles during winter

    Författare :Pushan Bag; Stefan Jansson; Fransis Andre Wollman; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Scots Pine; Norway spruce; Photosynthesis; Winter adaptation; biologisk kemi; biological chemistry; biology; biologi; molekylärbiologi; Molecular Biology; Physiological Botany; fysiologisk botanik;

    Sammanfattning : Plants and other green organisms harvest sunlight by green chlorophyll pigments and covertit to chemical energy (sugars) and oxygen in a process called photosynthesis providing the foundation for life on Earth. Although it is unanimously believed that oceanic phytoplanktons are the main contributors to the global photosynthesis, the contribution of coniferous boreal forests distributed across vast regions of the northern hemisphere cannot be undermined. LÄS MER

  5. 14. Isolation, Synthesis and Structure-Activity Relationships of Antifeedants against the Pine Weevil, Hylobius Abietis

    Författare :Carina Eriksson; Christina Moberg; John Pickett; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Pine weevil; Hylobius abietis; semiochemicals; antifeedant; feeding deterrent; feeding stimulant; bark extract; carboxylic acid; piperidine alkaloids; structure-activity; cinnamic aldehyde; benzaldehyde; Organic chemistry; Organisk kemi;

    Sammanfattning : The large pine weevil, Hylobius abietis L., is a major insect pest on conifer seedlings in northern Europe. Due to its feeding newly planted trees get girdled, resulting in high seedling mortality (up to 80%). As a consequence great financial losses to the forest industry occur. LÄS MER

  7. 15. Airborne lipophilic pollutants in pine needles

    Författare :Henrik Kylin; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Föroreningar; Miljö; Luftföroreningar; Ekotoxikologi;

    Sammanfattning : .... LÄS MER