Sökning: "permittivity"

Visar resultat 11 - 15 av 90 avhandlingar innehållade ordet permittivity.

1. 11. Novel RF MEMS Devices Enabled by Three-Dimensional Micromachining

   Författare :Umer Shah; Joachim Oberhammer; Raafat Mansour; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Microelectromechanical systems; MEMS; Radio frequency microelectromechanical systems; RF MEMS; Micromachined transmission line; Micromachining; Tuneable capacitor; Switched capacitor; Coupled-line coupler; Tuneable directional coupler; Intermodulation distortion; MEMS varactor; Two-tone IIP3 measurement; Passive components and circuits; Reliability; Magnetic materials; NiFe multilayer composite; Permeability; Permittivity; Micromachined inductors;

   Sammanfattning : This thesis presents novel radio frequency microelectromechanical (RF MEMS) circuits based on the three-dimensional (3-D) micromachined coplanar transmission lines whose geometry is re-configured by integrated microelectromechanical actuators. Two types of novel RF MEMS devices are proposed. LÄS MER

3. 12. Dielectric properties of poly(ethyelene-co-butyl acrylate) filled with Alumina nanoparticles

   Författare :Nadejda Jäverberg; Hans Edin; Eva Mårtensson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nanocomposites; poly ethylene-co-butyl acrylate ; EBA; alumina; dielectric permittivity; absorbed water; humidity; temperature; dielectric spectroscopy; partial discharge; electrical treeing; Electrical engineering; Elektroteknik;

   Sammanfattning : In this work dielectric properties of the poly(ethylene-co-butyl acrylate)filled with alumina nanoparticles are evaluated. These nanocomposite materialswere manufactured at the department of Fibre and Polymer Technology,KTH.This study is limited to the properties of general importance for the AC applications. LÄS MER

4. 13. Microfluidics at High Pressures : Understanding, Sensing, and Control

   Författare :Martin Andersson; Lena Klintberg; Cyril Aymonier; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High-pressure microfluidics; supercritical CO2; compressible flow; relative permittivity; integrated electrodes; Teknisk fysik med inriktning mot mikrosystemteknik; Engineering Science with specialization in Microsystems Technology;

   Sammanfattning : This thesis explores understanding, sensing, and control in high-pressure microfluidics. The high-pressure regime allows fluids to be forced through narrow channels at substantial speed and creates conditions for fluids of high density and low viscosity—features desired in flow-based chemical analyses. LÄS MER

5. 14. 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

7. 15. Electrical Characterization of Partial Discharge Resistant Enamel Insulation

   Författare :Tuan Anh Hoang; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Enamel wire insulation; dipolar polarization; charge injection; charge transport; chromium oxide; dc conductivity; partial discharge; twisted pair.; dielectric permittivity;

   Sammanfattning : Adjustable speed drives for rotating machines have become increasingly popular as they provide possibilities of smooth and accurate process control as well as for energy savings. In such systems, due to the fact that the voltage applied at terminals of motor windings is no longer purely sinusoidal but characterized by a high content of harmonics, the appearing electrical and thermal stresses yield premature failures of the winding insulation, mainly because of an increased partial discharge (PD) activity. LÄS MER