Sökning: "Geometric structure"

Visar resultat 16 - 20 av 189 avhandlingar innehållade orden Geometric structure.

  1. 16. Multicomponent Clusters/Nanoparticles : An Investigation of Electronic and Geometric Properties by Photoelectron Spectroscopy

    Författare :Chaofan Zhang; Olle Björneholm; Maxim Tchaplyguine; Svante Svensson; Gerd Ganteför; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Clusters; Nanoparticles; Alloy; Atmospheric chemistry; Alkali halide; Transition metals; X-ray Photoelectron spectroscopy; Polarizability; Core-shell; Sandwich structure; MAX-lab; BESSY II;

    Sammanfattning : Clusters/nanoparticles are aggregates of a “small” number of building blocks, atoms or molecules, ranging from two up to millions of atoms. Two main groups of clusters have been studied using photoelectron spectroscopy based on synchrotron radiation. LÄS MER

  2. 17. Geometric discretization for incompressible magnetohydrodynamics on the sphere

    Författare :Michael Roop; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lie-Poisson structure; magnetohydrodynamics; Hamiltonian dynamics; magnetic extension; Casimirs; symplectic Runge-Kutta integrators;

    Sammanfattning : Many physical processes are modelled by partial differential equations (PDE), and their efficient discretization is still a challenging problem and an actively developing field. An important class of models arising in mathematical physics represents PDEs formulated in terms of a Lie-Poisson structure on the dual of infinite-dimensional Lie algebras, such as the Lie algebra of vector fields. LÄS MER

  3. 18. Enhancing geometric maps through environmental interactions

    Författare :Sergio Caccamo; Danica Kragic; Petter Ögren; Robin Murphy; KTH; []
    Nyckelord :Gaussian Processes Robotics UGV Active perception geometric maps; Computer Science; Datalogi;

    Sammanfattning : The deployment of rescue robots in real operations is becoming increasingly commonthanks to recent advances in AI technologies and high performance hardware. Rescue robots can now operate for extended period of time, cover wider areas andprocess larger amounts of sensory information making them considerably more usefulduring real life threatening situations, including both natural or man-made disasters. LÄS MER

  4. 19. Polynomial Solvers for Geometric Problems - Applications in Computer Vision and Sensor Networks

    Författare :Yubin Kuang; Matematik LTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; polynomial solver; geometric problems; computer vision; sensor networks; symmetry;

    Sammanfattning : Given images of a scene taken by a moving camera or recordings of a moving smart phone playing a song by a microphone array, how hard is it to reconstruct the scene structure or the moving trajectory of the phone? In this thesis, we study and solve several fundamental geometric problems in order to provide solutions to these problems. The key underlying technique for solving such geometric problems is solving systems of polynomial equations. LÄS MER

  5. 20. Studies of Model Nanostructured Materials : Geometric and Electronic Structure, and sub-10 fs Charge Transfer Dynamics

    Författare :Joachim Schnadt; Wilfried Wurth; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; Physics; Fysik; fysik; Physics;

    Sammanfattning : A number of nanostructured systems has been investigated by means of Photoemission and X-ray absorption spectroscopies and by Scanning tunneling microscopy with emphasis on the geometric and electronic structure and the excited-state charge transfer dynamics. These systems comprise aromatic molecules on semiconductor surfaces (titanium dioxide), metal clusters, and an alkali-C60 compound. LÄS MER