Sökning: "backscattering"

Visar resultat 1 - 5 av 67 avhandlingar innehållade ordet backscattering.

1. 1. Tight-binding calculations of electron scattering rates in semiconducting zigzag carbon nanotubes

   Författare :Kannan Thiagarajan; Ulf Lindefelt; Hans-Erik Nilsson; Sven Öberg; Mittuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Tight-binding; carbon nanotubes; electron-phonon scattering; backscattering; forward scattering; Semiconductor physics; Halvledarfysik;

   Sammanfattning : The technological interest in a material depends very much on its electrical, magnetic, optical and/or mechanical properties. In carbon nanotubes the atoms form a cylindrical structure with a diameter of the order 1 nm, but the nanotubes can be up to several hundred micrometers in length. LÄS MER

3. 2. Modelling Microwave Backscattering from Sea Ice for Synthetic-Aperture Radar Applications

   Författare :Anders Carlström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; synthetic-aperture radar; microwave; surface roughness; sea ice; backscattering models;

   Sammanfattning : The spaceborne synthetic-aperture radar (SAR) is considered one of the key instruments for monitoring the ice cover in polar oceans and regional seas. This thesis is concerned with applications of electromagnetic scattering theory and SAR system theory for modelling the response of different types of sea ice in SAR imagery. LÄS MER

4. 3. SAR Remote Sensing of Forests, from Microwaves to VHF

   Författare :Hans Israelsson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; microwave; backscattering models; SAR; VHF; vegetation;

   Sammanfattning : The number of SAR systems available for civilian remote sensing purposes has grown in the nineties. A Synthetic Aperture Radar produces high resolution images of the earth independent on daylight and atmospheric conditions. This thesis mainly examines the applications of SAR remote sensing to monitoring forested areas. LÄS MER

5. 4. Ultrasound Contrast Agents Loaded with Magnetic Nanoparticles : Acoustic and Mechanical Characterization

   Författare :VeeraVenkata Satyanarayana Kothapalli; Lars-Åke Brodin; Jan Engvall; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ultrasound contrast agents; SPION nanoparticles; harmonic oscillation; backscattering power; attenuation coefficient; phase velocity; nonlinear equation of motion;

   Sammanfattning : The current methodologies in body scanning diagnostic uses different simultaneous imaging modalities like Ultrasound (US), magnetic resonance imaging (MRI), single photon emission tomography (SPECT) and positron emission tomography (PET). The field requires combination of different modalities for effective use in clinical diagnostics. LÄS MER

7. 5. A Two-stage Numerical Procedure for an Inverse Scattering Problem

   Författare :John Bondestam Malmberg; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; coefficient inverse problem; inverse scattering; backscattering data; approximate global convergence; finite element method; adaptivity; a posteriori error analysis; a posteriori error analysis;

   Sammanfattning : In this thesis we study a numerical procedure for the solution of the inverse problem of reconstructing location, shape and material properties (in particular refractive indices) of scatterers located in a known background medium. The data consist of time-resolved backscattered radar signals from a single source position. LÄS MER