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Coming dissertations at TekNat

  • Theoretical Investigations of Two-Dimensional Materials : Studies on Electronic, Magnetic, Mechanical, and Thermal Properties

    Author: Xin Chen
    Publication date: 2020-11-09 07:50

    Two-dimensional (2D) materials have been paid enormous attention since the first realization of graphene in 2004, in connection to high-speed flexible electronics, 2D magnetism, optoelectronics, and so on. Apart from graphene, many new 2D materials with special properties have been predicted and synthesized. For the understanding of several interesting phenomena and prediction of new 2D materials, materials-specific density functional theory (DFT) plays a very important role.

    In this thesis, based on first-principles calculations, structural, magnetic, electronic, mechanical, and thermal transport properties of two kinds of 2D systems are investigated.

    The first kind of 2D materials is based on the synthesized material or the predicted structure with ultralow energy. These materials were functionalized by adsorbing transition metal atoms or oxygen atoms, which makes a significant difference in the properties. A part of the thesis covers the study of the self-assembly process of 3d transition metal hexamers on graphene with different defects. Interestingly, it is found that the easy axis of magnetization can be tuned between in-plane and out-of-plane directions in...

  • Learning Physics through Transduction : A Social Semiotic Approach

    Author: Trevor Stanton Volkwyn
    Publication date: 2020-11-06 10:30

    This doctoral thesis details the introduction of the theoretical distinction between transformation and transduction to Physics Education Research. Transformation refers to the movement of meaning between semiotic resources within the same semiotic system (e.g. between one graph and another), whilst the term transduction refers to the movement of meaning between different semiotic systems (e.g. diagram to graph). A starting point for the thesis was that transductions are potentially more powerful in learning situations than transformations, and because of this transduction became the focus of this thesis. The thesis adopts a social semiotic approach. In its most basic form, social semiotics is the study of how different social groups create and maintain their own specialized forms of meaning making. In physics education then, social semiotics is interested in the range of different representations used in physics, their disciplinary meaning, and how these meanings may be learned. Students need to gain representational competence in interpreting and using the different representations they meet in their physics education and this thesis...