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Theoretical studies of rolled-up and wrinkled nanomembranes
Čendula, Peter ; Holý, Václav (advisor) ; Fedorchenko, Alexander I. (referee) ; Onck, Patrick N. (referee)
Title: Theoretical studies of rolled-up and wrinkled nanomembranes Author: Mgr. Peter Cendula Department: Department of Condensed Matter Physics Thesis Supervisors: Prof. Dr. Oliver G. Schmidt, Prof. RNDr. Václav Holý, CSc. Abstract : The thesis is devoted to three similar topics from the field of rolled-up and wrinkled nanomembranes. We start by recalling classical theory of thin plates, which will be used to describe deformation of nanomembranes. In the first topic, relaxation of internal strain is studied when a flat film is partially released from the substrate by etching the sacrificial layer underneath. Energetic competition of the tube and wrinkle shape is quantitatively investigated. Similar model is used to investigate the limiting maximum value of tube rotations. In the second topic, roll-up of initially wrinkled film is shown to favor tubes forming on the flat edge of rectangular wrinkled pattern, enabling precise control of tube position. Experiment is provided to justify our theoretical predictions. In the third topic, quantum well is assumed inside a wrin- kled nanomembrane. Shift of transition energy induced by lateral modulation due to bending strain is quantified, being of interest for strain-sensitive optical detectors and emitters. In addition, lateral localization of electron and hole due to...
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Theoretical studies of rolled-up and wrinkled nanomembranes
Čendula, Peter ; Holý, Václav (advisor) ; Fedorchenko, Alexander I. (referee) ; Onck, Patrick N. (referee)
Title: Theoretical studies of rolled-up and wrinkled nanomembranes Author: Mgr. Peter Cendula Department: Department of Condensed Matter Physics Thesis Supervisors: Prof. Dr. Oliver G. Schmidt, Prof. RNDr. Václav Holý, CSc. Abstract : The thesis is devoted to three similar topics from the field of rolled-up and wrinkled nanomembranes. We start by recalling classical theory of thin plates, which will be used to describe deformation of nanomembranes. In the first topic, relaxation of internal strain is studied when a flat film is partially released from the substrate by etching the sacrificial layer underneath. Energetic competition of the tube and wrinkle shape is quantitatively investigated. Similar model is used to investigate the limiting maximum value of tube rotations. In the second topic, roll-up of initially wrinkled film is shown to favor tubes forming on the flat edge of rectangular wrinkled pattern, enabling precise control of tube position. Experiment is provided to justify our theoretical predictions. In the third topic, quantum well is assumed inside a wrin- kled nanomembrane. Shift of transition energy induced by lateral modulation due to bending strain is quantified, being of interest for strain-sensitive optical detectors and emitters. In addition, lateral localization of electron and hole due to...
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Scaling law for capillary-driven flows
Fedorchenko, Alexander I. ; Stachiv, Ivo
Theoretical investigation of the capillary-driven flows has been carried out. Based on the virial theorem it has been proven that a family of the capillary-driven flows is described by power laws with an universal set of exponents: 3/2, – 1/3, – 1/2 which interrelate the characteristic spatial (L), temporal (T) and velocity (U) scales.
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On phenomenon of the rotating inertia-gravity wave formation at in- and outflow of the liquid from cylindrical container
Fedorchenko, Alexander I. ; Stachiv, Ivo
Experimental observations of the spontaneous formation of the rotating inertia-gravity wave inside cylindrical container have been carried out. The experimental setup combines both inflow and outflow. The inflow is realized as the overflow of liquid over the container’s edge, while the outflow is performed through an outlet at the bottom of the container’s center. Experiments revealed three different regimes of establishment flow inside the container: 1) flow without formation of the inertia-gravity wave, 2) flow with surface perturbations which are initially localized nearby the container’s wall, and 3) the formation of the rotating inertia-gravity wave.
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