Sökning: "maximum principle"

Visar resultat 36 - 40 av 74 avhandlingar innehållade orden maximum principle.

  1. 36. The Influence of Interlayer Exchange Coupling on Magnetic Ordering in Fe-based Heterostructures

    Författare :Martin Pärnaste; Björgvin Hjörvarsson; Bryan Hickey; Uppsala universitet; []
    Nyckelord :Physics; magnetism; magnetic dimensionality; MOKE; magneto-optics; hydrogen loading; phase transitions; Fysik;

    Sammanfattning : Temperature dependent magnetization measurements were conducted on Fe-based heterostructures. A linear increase of the magnetic critical temperature with increasing Fe thickness was found for Fe/V superlattices with strong interlayer exchange coupling. LÄS MER

  3. 37. On millimeter and submillimeter wave focal plane arrays implemented with MEMS waveguide switches

    Författare :Henrik Frid; Joachim Oberhammer; Vessen Vassilev; Mikro- och nanosystemteknik KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Extended Hemispherical Lens; Beam Steering; Focal Plane Array FPA ; Ray-Tracing; RF MEMS; waveguide switch; micromachined waveguide; submillimeter-wave; rectangular waveguide; terahertz; lenses; antenna theory; silicon; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : This thesis presents research towards enabling micromachined millimeter and submillimeter wave focal plane arrays (FPAs). The FPAs operate under the following principle: a switch network consisting of microelectromechanical (MEMS) switches, integrated with micromachined waveguides, is used to feed an array of antenna elements, located in the focal plane of a high-gain quasi-optical system. LÄS MER

  4. 38. Free Volume Determination in Polymers and Polymer Blends

    Författare :Camilla Wästlund; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; positronium formation; crystallinity; polymer blends; inhibition; polymers; free volume; positron annihilation; phase separation; distribution;

    Sammanfattning : The free volume of a polymer, which corresponds to the unoccupied regions accessible to segmental motions, is an important parameter for understanding and predicting many of its characteristic properties. The concept of free volume is the basis for understanding the molecular mobility in polymers. LÄS MER

  5. 39. Towards the Limits of Nonlinearity Compensation for Fiber-Optic Channels

    Författare :Naga Vishnukanth Irukulapati; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Viterbi algorithm; fiber-optic channel; stochastic digital backpropagation; performance limits; factor graphs; near-MAP detector; Digital backpropagation; nonlinear compensation; mutual information;

    Sammanfattning : The performance of long-haul coherent optical systems is fundamentally limited by fiber nonlinearity and its interplay with chromatic dispersion and noise. Due to nonlinearity, the signal propagating through the fiber interacts with itself and with the noise generated from the inline amplifiers. LÄS MER

  7. 40. Convection-diffusion equation in unbounded cylinder and related homogenization problems

    Författare :Iryna Pankratova; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik;

    Sammanfattning : The thesis consists of two closely related papers (A and B). Paper A is concerned with the study of the behaviour at infinity of solutions to second order elliptic equation with first order terms stated in a half-cylinder. LÄS MER