Search for dissertations about: "complex conductivity"

Showing result 1 - 5 of 120 swedish dissertations containing the words complex conductivity.

  2. 1. Theoretical Studies on Electronic Structure, Spectra and Conductivity of Pristine and Alkali Doped Polyacetylene

    Author : Lucía Mercedes Rodrigues Monge; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; theoretical calculations; electron transfer; conductivity; polyacetylene; alkali metal; ab-initio methods; charge transport; semiempirical methods; doping;

    Abstract : The present thesis is a theoretical investigation of the electronic properties of linear polyenes to get an insight into conductive phenomena in pristine and doped polyacetylene. Conductivity in polyacetylene is a complex phenomena and cannot be treated within simple band models. READ MORE

  4. 2. Melt Spun Electro-Conductive Polymer Composite Fibers

    Author : Azadeh Soroudi; Högskolan i Borås; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; conductive fibres; composites; blending; melt spinning; morphology; polyaniline; carbon nanotube; polypropylene; polyamide; draw-ratio; conductivity; Energi och material;

    Abstract : One interesting approach is the development of conductive polymer composite fibers for innovative textile applications such as in sensors, actuators and electrostatic discharge. In this study, conductive polymer composite fibers were prepared using several different blends containing conductive components: a conjugated polymer (polyaniline-complex) and/or carbon nanotubes. READ MORE

  5. 3. Characteristic properties of two-dimensional superconductors close to the phase transition in zero magnetic field

    Author : Kateryna Medvedyeva; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; superconductor; two dimensions; phase transition; vortex; currentvoltage characteristics; complex conductivity; scaling; critical exponents; XY-type models; dynamics; Physics; Fysik; fysik; Physics;

    Abstract : The main focus of this thesis lies on the critical properties of twodimensional (2D) superconductors in zero magnetic field. Simulations based on variants of the 2D XY model are shown to give characteristic features close to the phase transition which agree qualitatively with experimental data. READ MORE

  6. 4. On the Zero and Low Field Vortex Dynamics : An Experimental Study of Type-II Superconductors

    Author : Örjan Festin; Peter Svedlindh; Piero Martinoli; Uppsala universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Engineering physics; high temperature superconductors; thermal fluctuations; YBCO; MgB2; anisotropic superconductors; vortex dynamics; Kosterlitz-Thouless transition; current voltage characteristics; complex conductivity; Flux noise; Teknisk fysik; Engineering physics; Teknisk fysik;

    Abstract : Dynamic properties of type-II superconductors have been experimentally studied in zero and low magnetic fields using SQUID magnetometry and I–V measurements.In zero magnetic field close to the critical temperature, the physical properties of type-II superconductors are dominated by spontaneously created vortices. READ MORE

  7. 5. Complex Phase Behavior in Thermoelectric Mg2Si1-xSnx Alloys and Development of Transient Plane Source Method for Structural Characterization

    Author : Andrey Sizov; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; multiphase structure; quality control; inhomogeneity tests; Rietveld refinement; Transient Plane Source method; isotropic and anisotropic materials; defects detection; advance measurements of thermal properties; X-ray diffraction; structural characterization; spark plasma sintering; magnesium silicide-stannide alloys; complex behavior; thermoelectric properties; thermal conductivity vs. probing depth;

    Abstract : The thermoelectric effect was discovered nearly 200 years ago, but it started to be utilized for waste heat recovery only fairly recently. From an economical point of view, such applications requires a cheap and efficient material, which is able to convert heat energy into electricity. READ MORE