Sökning: "pulse propagation"

Visar resultat 16 - 20 av 78 avhandlingar innehållade orden pulse propagation.

  1. 16. Combination of optical methods for studies in combustion and wave propagation

    Författare :Roger Mattsson; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Experimentell mekanik; Experimental Mechanics;

    Sammanfattning : In this thesis, different optical methods were combined for studies of combustion processes in gases and transient wave propagation in plates and water. Pulsed TV holography was used in all these projects. LÄS MER

  3. 17. Features and Origin of Electromagnetic Fields Generated by Lightning Flashes

    Författare :Mohd Muzafar Ismail; Vernon Cooray; Farhad Rachidi; Uppsala universitet; []
    Nyckelord :negative cloud-to-ground lightning flashes; HF and VHF radiation; chaotic pulse trains; lightning initiation; zero-crossing time; electromagnetic fields; Engineering Science with specialization in Atmospheric Discharges; Teknisk fysik med inriktning mot atmosfäriska urladdningar;

    Sammanfattning : Negative cloud-to-ground (CG) lightning flashes transport negative charge from cloud to ground. Negative ground flashes typically involve various processes identified as preliminary breakdown, stepped leader, return stroke, dart leader, dart-stepped leader, subsequent return stroke, and cloud activity between strokes, such as regular pulse trains and chaotic pulse trains. LÄS MER

  4. 18. Pulsed holographic interferometry for the study of bending wave propagation in paper and in tubes

    Författare :Kenneth Olofsson; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Experimental Mechanics; Experimentell mekanik;

    Sammanfattning : Pulsed Holographic Interferometry (HI), is used to record propagating transient bending waves in plates and shells. These waves are generated mechanically by impact of a small steel sphere or optically by focusing a high energy laser pulse at the surface of the tested object. LÄS MER

  5. 19. Problems in Nonlinear Wave Propagation A Walk in Physics from Plasmas to Bose-Einstein Condensates with some Examples of Unifying Themes in Nature

    Författare :Federica Cattani; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear Schroedinger equation; Bose-Einstein condensates; plasma; laser; optics;

    Sammanfattning : Waves are a phenomenon that can be found virtually everywhere in nature. A first description of wave propagation can be given in the linear limit, but the nonlinear regime of propagation is of the utmost importance, also in view of possible applications in several scientific fields. LÄS MER

  7. 20. Optimisation and Application of Intense High-Order Harmonic Pulses

    Författare :Lena Roos; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Coherent radiation; Optimisation; Multiphoton ionisation; Phase matching; Physics; Fysik; Atomic and molecular physics; Atom- och molekylärfysik; Laserteknik; Laser technology; High-power lasers; Short pulses; High-order harmonic generation; Short wavelength; Fysicumarkivet A:2001:Roos;

    Sammanfattning : The high-order harmonics that are created in the interaction between an intense laser pulse (around 1014 W/cm2) and a gas medium are studied. The high-order harmonic radiation is a relatively new source of coherent radiation in the short wavelength range. LÄS MER