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Visar resultat 1 - 5 av 15 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Nonlocal Correlations in Density Functional Theory

   Författare :Henrik Rydberg; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bonding; GGA; adhesion; graphene; DFT; exchange; adsorption; LDA; first principles; polarization; vdW; determinants; correlation; graphite; surface states; van der Waals; density-functional theory; physisorption; nonlocal; functional;

   Sammanfattning : In Density Functional Theory, the widely used local and semilocal approximations to the exchange-correlation energy, the local density approximation (LDA) and the generalized gradient approximations (GGAs), lack a physical description of truly nonlocal correlation effects, which are absolutely essential for a proper description of soft matter. A scheme is proposed that provides a basis for systematic improvements beyond LDA and GGA, including correlations at intermediate and long range, giving rise to bonds of pure van der Waals type as well as more intricate, intermediate-range correlation bonds. LÄS MER

3. 2. Plasma membrane order; the role of cholesterol and links to actin filaments

   Författare :Jelena Dinic; Ingela Parmryd; Gerrit van Meer; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Membrane Organization; Lipid rafts; Actin; Laurdan; di-4-ANEPPDHQ; Cholesterol; T cell signaling; Colocalization; Generalized Polarization; Cell Biology; cellbiologi;

   Sammanfattning : The connection between T cell activation, plasma membrane order and actin filament dynamics was the main focus of this study. Laurdan and di-4-ANEPPDHQ, membrane order sensing probes, were shown to report only on lipid packing rather than being influenced by the presence of membrane-inserted peptides justifying their use in membrane order studies. LÄS MER

4. 3. Analysis and Design of Spatially-Coupled Codes with Application to Fiber-Optical Communications

   Författare :Christian Häger; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bit mapper; generalized product codes; generalized low-density parity-check codes; bounded-distance decoding; density evolution; spatial coupling; staircase codes.; braided codes; Bit-interleaved coded modulation;

   Sammanfattning : The theme of this thesis is the analysis and design of error-correcting codes that are suitable for high-speed fiber-optical communication systems. In particular, we consider two code classes. The codes in the first class are protograph-based low-density parity-check (LDPC) codes which are decoded using iterative soft-decision decoding. LÄS MER

5. 4. Analysis of Industrial Microwave Ovens

   Författare :Magnus Sundberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; source model; heat transfer; moment method; finite difference time domain; TM applicator; GMT; edge diffraction; thermal simulation; MMP; FDTD; generalized multipole technique; cost function; MM; optimization; magnetron; simulated annealing; multiple multipole program; microwave heating; edge overheating; TE applicator; tunnel-oven; applicator;

   Sammanfattning : This thesis deals with the analysis and design of microwave ovens used in the food industry. Such analysis is desirable in order to optimize the performance of the ovens and to reduce the time and expenses of developing new or improved ovens. LÄS MER

7. 5. Nonlinear Properties of III-V Semiconductor Nanowaveguides

   Författare :Eleonora De Luca; Marcin Swillo; Fabrice Raineri; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Optik och fotonik; Optics and Photonics;

   Sammanfattning : Nonlinear optics (NLO) plays a major role in the modern world: nonlinear optical phenomena have been observed in a wavelength range going from the deep infrared to the extreme ultraviolet, to THz radiation. The optical nonlinearities can be found in crystals, amorphous materials, polymers, liquid crystals, liquids, organic materials, and even gases and plasmas. LÄS MER