Search for dissertations about: "characteristic impedance"

Showing result 1 - 5 of 34 swedish dissertations containing the words characteristic impedance.

  1. 1. Transmission of waves through elastic and viscoelastic junctions

    Author : Tomas Nygren; Uppsala universitet; []
    Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Materials science; Wave; elastic; viscoelastic; extensional; characteristic impedance; junction; transmission; reflection; dissipation; optimisation; Materialvetenskap; Materials science; Teknisk materialvetenskap; Solid Mechanics; hållfasthetslära;

    Abstract : Transmission of extensional waves through elastic and viscoelastic junctions between elastic and collinear bars have been studied theoretically and experimentally. The models used can be interpreted also for other types of waves (e.g. dilatational waves, shear waves, electromagnetic waves) and systems. READ MORE

  2. 2. Pulmonary ventilation and perfusion assessed by electrical impedance tomography - Experimental studies in pigs

    Author : Anneli Fagerberg; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
    Keywords : electrical impedance tomography; V Q matching; pig; endotoxinaemic ALI; ACE inhibitor;

    Abstract : Pulmonary ventilation and perfusion and ventilation/perfusion (V/Q) matching determine gas exchange in every lung unit in the healthy state and in the pathologically altered lung. Mismatch of V and Q lead to hypoxaemia and hypercapnia and monitoring of V/Q relations are thus important in critical illness. READ MORE

  3. 3. Dynamic and quasi-stationary electrochromic response of amorphous tungsten oxide thin films : In situ combined electrochemical and optical measurements during lithium intercalation

    Author : Edgar Alonso Rojas González; Gunnar Niklasson; Aline Rougier; Uppsala universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Electrochromism; Optical absorption; Amorphous materials; Tungsten oxide; Electrochemical impedance spectroscopy; Color impedance spectroscopy; Intercalation; Engineering Science with specialization in Solid State Physics; Teknisk fysik med inriktning mot fasta tillståndets fysik;

    Abstract : Electrochromic (EC) materials can adjust their optical properties, reversibly, by means of an external electrical stimulus. They have relevant technological applications; for example, energy-efficient smart windows, which can adapt dynamically—according to the given environmental conditions—to control the heat and visible light fluxes between the interior and exterior of a building. READ MORE

  4. 4. Device Technology Based on High Temperature Superconductors and Microwave Breakdown in Gases

    Author : Martin Löfgren; Chalmers University of Technology; []
    Keywords : distortion; penetration depth; surface resistance; transmit-receive switch; coupled-grain model; high-power; microwave; pulse; surface impedance; breakdown; propagation; modulator; air; superconductor; transmission line; resonator; coplanar waveguide; plasma;

    Abstract : This thesis deals with two separate fields of microwave technology. The first section treats microwave characterization and applications of high temperature superconducting (HTS) thin films, while the second section treats microwave breakdown in transmit-receive (TR) switches and in air. Within the first section, four main topics are adressed. READ MORE

  5. 5. Kinetic investigation of LiMn2O4 for rechargeable lithium batteries

    Author : Anna-Karin Hjelm; KTH; []
    Keywords : linear sweep voltammetry; electrochemical impedance spectroscopy; potential step; in situ X-ray diffraction; microelectrodes; electrode kinetics; LiMn2O4 cathode; rechargeable lithium batteries;

    Abstract : This thesis is concerned with kinetic characterisation of theinsertion compound LiMn2O4, which is used as positive electrodematerial in rechargeable lithium batteries. Three different typesof electrode configurations have been investigated, namely singleparticles, thin films and composite electrodes. Differentelectrochemical techniques, i.e. READ MORE