Sökning: "Carbon Formation"

Visar resultat 1 - 5 av 653 avhandlingar innehållade orden Carbon Formation.

1. 1. Chemistry of Carbon Nanostructures : Functionalization of Carbon Nanotubes and Synthesis of Organometallic Fullerene Derivatives

   Författare :Claes-Henrik Andersson; Helena Grennberg; Nazario Martín León; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Carbon nanotubes; Fullerenes; Purification; Functionalization; Organometallic complexes; Kemi med inriktning mot organisk kemi; Chemistry with specialization in Organic Chemistry;

   Sammanfattning : This thesis is based on two main parts. The first part concerns purification and functionalization of carbon nanotubes (papers I-III), and the second part is related to the synthesis of organometallic fullerene derivatives (papers IV-VII): Two oxidative methods involving aqueous nitric acid were compared with respect to their capability to introduce carboxylic groups into single walled carbon nanotubes, and several literature methods for esterification and amidation of these groups have been evaluated with focus on efficiency and reproducibility in forming covalently functionalized products soluble in organic media. LÄS MER

3. 2. New Reactions with Allyl- and Allenylboron Reagents : Transition-Metal-Catalyzed and Transition-Metal-Free Carbon-Carbon Bond Formation Processes

   Författare :Dong Wang; Kálmán J. Szabó; Jianbo Wang; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; carbon-carbon bond formation; cross-coupling; organoboron compound; allylboron reagent; allylation; transition metal; metal carbene; allenylboron reagent; transition metal free; diazo compound; tosylhydrazone; quinone; organisk kemi; Organic Chemistry;

   Sammanfattning : Organoboron compounds have been widely used in carbon-carbon bond formation reactions in organic synthesis and catalysis. This thesis is focused on cross-coupling reactions of allyl-, allenylboronic acids and their ester derivatives via transition metal catalysis or transition-metal-free processes. LÄS MER

4. 3. Mechanical behaviour of carbon nanostructures

   Författare :Henrik Jackman; Krister Svensson; Pavel Krakhmalev; Eleanor E. B. Campbell; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; carbon nanotubes; CNT; multiwalled carbon nanotubes; MWCNT; rippling; buckling; mechanical properties; transmission electron microscopy; TEM; scanning electron microscopy; SEM; atomic force microscopy; AFM; Young’s modulus; in situ TEM; in situ SEM; Physics; Fysik;

   Sammanfattning : AbstractCarbon nanotubes (CNTs) have extraordinary mechanical and electrical properties. Together with their small dimensions and low density, they are attractive candidates for building blocks in future nanoelectromechanical systems and for many other applications. LÄS MER

5. 4. Mechanical properties of carbon nanotubes and nanofibers

   Författare :Henrik Jackman; Krister Svensson; Pavel Krakhmalev; Håkan Olin; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; atomic force microscopy; bending; carbon nanotubes; deformation; scanning electron microscopy; Young s modulus; carbon nanofibers; mechanical properties; Physics; Fysik;

   Sammanfattning : Carbon nanotubes (CNTs) have extraordinary electrical and mechanical properties, and many potential applications have been proposed, ranging from nanoscale devices to reinforcement of macroscopic structures. However, due to their small sizes, characterization of their mechanical properties and deformation behaviours are major challenges. LÄS MER

7. 5. High-resolution mapping and spatial variability of soil organic carbon storage in permafrost environments

   Författare :Matthias Benjamin Siewert; Gustaf Hugelius; Peter Kuhry; Iain Hartley; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; carbon; soil organic carbon; permafrost; soil; land cover classification; digital soil mapping; machine-learning; ecosystem; mapping; landscape studies; Siberia; Arctic; Physical Geography; naturgeografi;

   Sammanfattning : Large amounts of carbon are stored in soils of the northern circumpolar permafrost region. High-resolution mapping of this soil organic carbon (SOC) is important to better understand and predict local to global scale carbon dynamics. LÄS MER