| 1. |
- Löfås, Henrik, 1983-, et al.
(författare)
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Effective masses and electronic structure of diamond including electron correlation effects in first principles calculations using the GW-approximation
- 2011
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Ingår i: AIP Advances. - New York : AIP. - 2158-3226. ; 1:3, s. 032139-
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Tidskriftsartikel (refereegranskat)abstract
- We present calculated interband transitions and effective masses for diamond from first principles including electron correlation effects via the GW-approximation. Our findings are in agreement with experiments, already the first iteration of the GW-scheme gives a direct gap at the gamma-point of 7.38 eV and a indirect gap of 5.75 eV close to experimental values. For deeper bands a quasiparticle self-consistent method is necessary to accurately reproduce the valence band width to 23.1 eV. We also obtain effective hole masses along different symmetry axes and electron conduction masses, ml = 1.1m0 and mt = 0.22m0
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| 2. |
- Karabulut, Erdem, 1983-, et al.
(författare)
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Adhesive Layer-by-Layer Films of Carboxymethylated Cellulose Nanofibril Dopamine Covalent Bioconjugates Inspired by Marine Mussel Threads
- 2012
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 6:6, s. 4731-4739
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Tidskriftsartikel (refereegranskat)abstract
- The preparation of multifunctional films and coatings from sustainable, low-cost raw materials has attracted considerable interest during the past decade. In this respect, cellulose-based products possess great promise due not only to the availability of large amounts of cellulose in nature but also to the new classes of nanosized and well-characterized building blocks of cellulose being prepared from trees or annual plants. However, to fully utilize the inherent properties of these nanomaterials, facile and also sustainable preparation routes are needed. In this work, bioinspired hybrid conjugates of carboxymethylated cellulose nanofibrils (CNFC) and dopamine (DOPA) have been prepared and layer-by-layer (LbL) films of these modified nanofibrils have been built up in combination with a branched polyelectrolyte, polyethyleneimine (PEI), to obtain robust, adhesive, and wet-stable nanocoatings on solid surfaces. It is shown that the chemical functionalization of CNFCs with DOPA molecules alters their conventional properties both in liquid dispersion and at the interface and also influences the LbL. film formation by reducing the electrostatic interaction. Although the CNFC-DOPA conjugates show a lower colloidal stability in aqueous dispersions due to charge suppression, it was possible to prepare the LbL films through the consecutive deposition of the building blocks. Adhesive forces between muttilayer films prepared using chemically functionalized CNFCs and a silica probe are much stronger in the presence of Fe3+ than those between a multilayer film prepared from unmodified nanofibrils and a silica probe. The present work demonstrates a facile way to prepare chemically functionalized cellulose nanofibrils whereby more extended applications can produce novel cellulose-based materials with different functionalities.
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| 3. |
- Xu, Johanna, 1989-, et al.
(författare)
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Carbon fiber composites with battery function : Stresses and dimensional changes due to Li-ion diffusion
- 2018
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Ingår i: Journal of composite materials. - : Sage Publications. - 0021-9983 .- 1530-793X. ; 52:20, s. 2729-2742
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Tidskriftsartikel (refereegranskat)abstract
- Structural composite materials that simultaneously carry mechanical loads, while storing electrical energy offers the potential of significantly reduced total component weight owing to the multifunctionality. In the suggested micro-battery, the carbon fiber is employed as a negative electrode of the battery and also as a composite reinforcement material. It is coated with a solid polymer electrolyte working as an ion conductor and separator while transferring mechanical loads. The coated fiber is surrounded by a conductive positive electrode material matrix. This paper demonstrates a computational methodology for addressing mechanical stresses arising in a conceptualized micro-battery and dimensional changes of the cell during electrochemical cycling, caused by time-dependent gradients in lithium ion concentration distribution.
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