Sökning: "plane wave"

Visar resultat 1 - 5 av 48 uppsatser innehållade orden plane wave.

  1. 1. Effectiveness of Iterative Algorithms for Recovering Phase in the Presence of Noise for Coherent Diffractive Imaging

    Master-uppsats, Göteborgs universitet / Institutionen för fysik

    Författare :Henry Wittler; [2023-11-29]
    Nyckelord :;

    Sammanfattning : Methods of coherent diffractive imaging (CDI) rely on iterative algorithms to reconstruct the complex exit-surface wave (ESW) of the object being imaged from the measured diffraction intensity only. In this thesis we investigate by simulation the artifacts on reconstruction when noise are present in the measurement. LÄS MER

  3. 2. Numerical Simulations of Resonant Tunnelling Diodes

    Kandidat-uppsats, KTH/Skolan för teknikvetenskap (SCI)

    Författare :Love Sundström; Alexander Holmström Janeld; [2023]
    Nyckelord :Quantum mechanics; numerical methods; resonant tunnelling diode;

    Sammanfattning : In this thesis, four different numerical techniques are implemented for the purpose of simulating resonant tunnelling diodes (RTDs). The chosen methods were: piecewise constant transfer matrix (TMM-C), piecewise linear transfer matrix (TMM-L), quantum transmitting boundary method (QTBM), and the Crank-Nicolson method (CN). LÄS MER

  4. 3. Acoustic Characterization of Catalyst

    Kandidat-uppsats, KTH/Skolan för teknikvetenskap (SCI)

    Författare :Surachit Dokson; [2023]
    Nyckelord :;

    Sammanfattning : The WHO has set a sound level threshold of 55 dB, beyond which noise is considered harmful to humans when exposed for an extended period of time. It is, however, estimated by the European Environmental Agency that over 110 million people in the EU are regularly exposed to levels of traffic noise above 55 dB. LÄS MER

  5. 4. Predicting eigenvalues and eigenmodes in non-rectangular rooms with machine learning techniques

    Master-uppsats, KTH/Teknisk akustik

    Författare :Oscar Lundin; [2022]
    Nyckelord :Machine learning; Finite elements; Plane wave decomposition; ResNet; Room acoustics; Tensorflow; Keras; Eigenfrequency prediction; Maskininlärning; Finita elementmetoden; Planvåguppdelning decomposition; Rumsakustik; ResNet; Tensorflow; Keras; Prediktering av egenvärden; Egenfrekvenser; Egenmoder.;

    Sammanfattning : Knowing the eigenfrequencies and eigenmodes is of great importance to interior design and a common acoustic engineering problem. Challenges in noise control makes knowing the lower eigenfrequencies particularly important. LÄS MER

  7. 5. Ultrasound Imaging Velocimetry using Polyvinyl Alcohol Shelled Microbubbles

    Master-uppsats, KTH/Skolan för kemi, bioteknologi och hälsa (CBH)

    Författare :Ida Johansson; [2022]
    Nyckelord :Ultrasound imaging velocimetry; ultrasound contrast agents; polyvinyl alcohol; microbubbles; echo particle image velocimetry; Ultrasound imaging velocimetry; ultraljudskontrastmedel; polyvinylalkohol; mikrobubblor; echo particle image velocimetry;

    Sammanfattning : Current research within the field of ultrasound contrast agents (UCAs) aims at developing capsules which are not only acoustically active, but also have a chemically modifiable surface. This enables use in new areas, including targeted drug delivery and theranostics. LÄS MER