Search for dissertations about: "high frequencies"

Showing result 1 - 5 of 770 swedish dissertations containing the words high frequencies.

2. 1. High-Efficiency SiC Power Conversion : Base Drivers for Bipolar Junction Transistors and Performance Impacts on Series-Resonant Converters

   Author : Georg Tolstoy; Hans-Peter Nee; Stig Munk-Nielsen; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Silicon Carbide; Bipolar Junction Transistor BJT ; Resonant converter; Series-resonant converter SLR ; Base drive circuits; High- Efficiency Converters; High-Frequency Converters; Electrical Engineering; Elektro- och systemteknik;

   Abstract : This thesis aims to bring an understanding to the silicon carbide (SiC) bipolar junction transistor (BJT). SiC power devices are superior to the silicon IGBT in several ways. They are for instance, able to operate with higher efficiency, at higher frequencies, and at higher junction temperatures. READ MORE

4. 2. High frequency electronic packaging : SBU-materials, material characterization, simulation and processing

   Author : Christian Johansson; Hjalmar Hesselbom; Linköpings universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; dielectric loss; high frequency electrical characterization; microwave circuits; multilayer thin film technology; ORMOCER; permittivity; sequential build up; silicone elastomer;

   Abstract : Electronic packaging continues to move towards improved performance and lower cost. Requirements of higher performance, reduced size, weight and cost of both High Density Interconnects (HDI) and high frequency (HF) devices has led to the search for new: materials, material combinations, methods, processes and production equipment. READ MORE

5. 3. Temporal Aspects of High-Intensity Laser-Matter Interactions

   Author : Johan Mauritsson; Atomfysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Particle Acceleration; Laser technology; Relativistic Self-Focusing; High-Intensity Lasers; Attosecond Pulses; Pulse Characterization; XUV; High-Order Harmonics; Ultrashort Pulses; Laserteknik; Atom- och molekylärfysik; Atomic and molecular physics; Fysicumarkivet A:2003:Mauritsson;

   Abstract : The availability of short-pulse, high-intensity lasers has opened doors to new areas in atomic and plasma physics. The short pulses (a few femtoseconds), that are available today, enable unprecedented temporal measurements, while the high peak power accessible (several terawatts) allows physicists to study the interaction between light and relativistic plasmas. READ MORE

6. 4. High Frequency Tyre Vibrations

   Author : Patrik Andersson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; local deformation; adhesion; tyre model; air pumping; parameter study; tyre road noise; tyre road prediction models; tyre noise;

   Abstract : High frequency (above 1 kHz) noise generation from the tyre/road interaction is still not fully understood and accurately modelled.Two noise generation mechanisms previously suggested in the literature are reviewed: air pumping and noise generation cased by adhesive effects between the tyre tread and road surface. READ MORE

7. 5. Nanostructured electromagnetic metasurfaces at optical frequencies

   Author : Nils Odebo Länk; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; high-index nanophotonics; colloidal lithography; metasurfaces; geometric resonances; nanostructures; plasmonics;

   Abstract : Electromagnetic metasurfaces are broadly defined as optically thin layersthat are structured on the subwavelength scale. In general, metasurfacesthus consist of nanoparticles, or other kinds of ”meta-atom”, arranged insome pattern where both the individual particle sizes and the inter-particledistances are much smaller than the wavelength. READ MORE