Sökning: "dielectric"

Visar resultat 16 - 20 av 449 avhandlingar innehållade ordet dielectric.

  1. 16. Phase characterization of polar liquid crystals using dielectric spectroscopy

    Författare :Jan Lagerwall; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; surface-induced phases; soft mode; dielectric spectroscopy; chiral-dopant mixtures; antiferroelectricity; ferroelectricity; Goldstone mode; polar liquid crystals;

    Sammanfattning : .... LÄS MER

  3. 17. Electrical Insulating Properties of Poly(Ethylene-co-Butyl Acrylate) Filled with Alumina Nanoparticles

    Författare :Nadejda Jäverberg; Hans Edin; John Fothergill; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nanocomposites; poly ethylene-co-butyl acrylate ; EBA; alumina; dielectric permittivity; absorbed water; humidity; temperature; dielectric spectroscopy; breakdown strength; pre-breakdown current;

    Sammanfattning : In this work the electrical insulating properties of the nanocomposite materials based on poly(ethylene-co-butyl acrylate) filled with alumina nanoparticles are studied. The dielectric properties chosen for the evaluation are the dielectric permittivity and loss as well as the breakdown strength and the pre-breakdown currents. LÄS MER

  4. 18. Arbitrary Waveform Impedance Spectroscopy for Characterization and Diagnostics of High Voltage Insulation

    Författare :Björn Sonerud; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; insulation testing; aging; monitoring; discrete Fourier transforms; Dielectric measurements; dielectric materials;

    Sammanfattning : In high voltage engineering the dielectric response technique is a widely used tool both for characterization of insulation materials and for diagnostics of components such as transformers and cables. Currently available techniques are not capable of measuring on-line which would be advantageous; when characterizing a material and evaluating the effect of different voltage magnitudes, waveforms and temperatures it is desirable to be able to observe the continuous development of the dielectric properties. LÄS MER

  5. 19. Partial Discharges Studied with Variable Frequency of the Applied Voltage

    Författare :Hans Edin; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; diagnostic methods; partial discharges; phase resolved; variable frequency; dielectric spectroscopy; dielectric response; harmonics; insulation; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : This thesis concerns partial discharge (PD) diagnostics withvariable frequency of applied voltage in the frequency range 1mHz - 400 Hz. The exploration of a new type of spectroscopythat combines partial discharge analysis and dielectricresponse is demonstrated. LÄS MER

  7. 20. Theoretical Reflections of Solvation in Polar Media

    Författare :Daniel Hagberg; Beräkningskemi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; kvantkemi; Teoretisk kemi; quantum chemistry; Theoretical chemistry; Coordination; Water; Uranyl; Intermolecular forces; Simulation; Dielectric; Cluster; Hofmeister series; Ion; Interaction; Dipole;

    Sammanfattning : Using experiments it is rather easy to measure things on the macroscopic length scale, while it is much harder to measure something in the microscopic world like molecular structure. The opposite is true in theoretical chemistry. LÄS MER