Sökning: "mechanical resonators"

Visar resultat 1 - 5 av 24 avhandlingar innehållade orden mechanical resonators.

1. 1. Conjoined piezoelectric harvesters and carbon supercapacitors for powering intelligent wireless sensors

   Författare :Henrik Staaf; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electrode material; coupled resonators; selftuning; Kinetic harvesting; Intelligent wireless sensor; piezoelectric energy harvesting; Supercapacitor; carbon nanomaterials;

   Sammanfattning : To achieve total freedom of location for intelligent wireless sensors (IWS), these need to be autonomous. To achive this today there is a need of broadband piezoelectric energy harvesting and a long-lasting energy. The Harvester need to be able to provide sufficient amount of energy for the intelligent wireless sensor to perform its task. LÄS MER

3. 2. Integration of graphene into MEMS and NEMS for sensing applications

   Författare :Xuge Fan; Frank Niklaus; Peter Steeneken; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Micro-electromechanical systems MEMS ; Nano-electromechanical systems NEMS ; heterogeneous 3D integration; Graphene; single-layer graphene; double-layer graphene; bilayer graphene; chemical vapor deposition CVD ; suspended graphene beams; suspended graphene membranes; doubly clamped; fully clamped; silicon on insulator SOI ; vapor hydrofluoric acid VHF ; Young’s modulus; built-in stress; built-in tension; piezoresistivity; gauge factor; accelerometer; resonators; electromechanical sensing; advanced transducers; humidity; gas sensing; sensitivity; CO2 sensing; graphene grain boundary; line defects; optical microscopy; wire bonding; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : This thesis presents a novel approach to integrate chemical vapor deposition (CVD) graphene into silicon micro- and nanoelectromechanical systems (MEMS/NEMS) to fabricate different graphene based MEMS/NEMS structures and explore mechanical properties of graphene as well as their applications such as acceleration sensing, humidity sensing and CO2 sensing. The thesis also presents a novel method of characterization of CVD graphene grain boundary based defects. LÄS MER

4. 3. Fractal superconducting resonators for the interrogation of two-level systems

   Författare :Sebastian Erik de Graaf; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cooper-pair box; decoherence; electron spin resonance; two-level systems; atomic force microscopy; quasiparticles; near-field scanning microwave microscopy; Superconducting resonators; circuit quantum electrodynamics;

   Sammanfattning : In this thesis we use high-Q superconducting thin-film microwave resonators to interact with several types of quantum mechanical two-level systems. Such a resonator is used as the central building block in a cryogenic near-field scanning microwave microscope (NSMM) to reach a completely new regime of NSMM operation. LÄS MER

5. 4. Innovative noise control in ducts

   Författare :Maaz Farooqui; Mats Åbom; Hans Bodén; Tamer Elnady; Jeong-Guon Ih; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Locally resonant materials; slow sound; acoustic impedance; metallic foam; low frequency noise; mufflers; lined ducts; grazing flow; flow duct; impedance eduction.; Vehicle and Maritime Engineering; Farkostteknik;

   Sammanfattning : The objective of this doctoral thesis is to study three different innovative noise control techniques in ducts namely: acoustic metamaterials, porous absorbers and microperforates. There has been a lot of research done on all these three topics in the context of duct acoustics. LÄS MER

7. 5. Design of soundproof panels via metamaterial concept

   Författare :Zibo Liu; Leping Feng; Romain Rumpler; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : The goal of the work is to find a way to improve the sound insulation properties of different types of panels in order to meet different requirements. Inspired by the nontrivial behavior of the locally resonant acoustic metamaterials, this concept is introduced into the design of structures in order to explore the potential ways to improve the sound insulation behavior in the relevant specific frequency regions. LÄS MER