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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
761

Characterization of monkey fat tissues : To assist their viability for fat intra-body communication as an early step of non-human primate testing (NHP)

Alyounes, Qsai, Razan, Alkari January 2022 (has links)
Fat intra-body communication is a newly proven concept that is built on using human fat tissues as a communication channel for electromagnetic waves inside the body. This allows for two implanted external devices to connect through an intra-body closed-loop communication channel. This concept utilizes the fact that the fat tissues have low dielectric properties and are located between two tissue layers, skin and muscle, which have high dielectric permittivity and high loss tangent so that the signal propagates and confines with lower losses within the fat tissue. In this study, the eligibility of using monkey fat tissues as a communication channel for intra-body communication is being investigated. This comes as a first step in a long process of testing implementing medical devices, mainly prosthetic limbs, on non-human primates using fat-IBC at microwave frequencies. To be able to do that, an experimental characterization of ex-vivo monkey fat, skin, and muscle tissues to explore their dielectric properties compared to those of humans is being carried out. This study of the dielectric properties of monkey tissues is the first of its kind to be carried out on two samples of ex-vivo monkey tissues. Calf tissues have also been investigated in the study to get an insight on the potential differences between human and non-human body tissues in general before doing measurements on monkey tissues. For the measurements, an RF network analyzer and an open-ended coaxial probe method have been implemented. Phantoms that mimic the human tissues have been fabricated to be used as a reference point. The initial investigation demonstrates that calf fat tissues have much higher dielectric properties than human fat tissues. Monkey fat, muscle, and skin tissues showed many similarities to human tissues regarding their dielectric properties. This indicates that monkey tissues can be used for fat intra-body communication. Future numerical and analytical modeling of the monkey tissues needs to be conducted to confirm and strengthen this finding.
762

Orientation Polarization Spectroscopy: Toward an Atomistic Understanding of Dielectric Relaxation Processes

Kremer, Friedrich, Kiprop Kipnusu, Wycliffe, Fränzl, Martin 17 January 2024 (has links)
The theory of orientation polarization and dielectric relaxation was developed by P. Debye more than 100 years ago. It is based on approximating a molecule by a sphere having one or more dipole moments. By that the detailed intra- and intermolecular interactions are explicitly not taken into consideration. In this article, the principal limitations of the Debye approximation are discussed. Taking advantage of the molecular specificity of the infrared (IR) spectral range, measurements of the specific IR absorption of the stretching vibration (OH) (at 3370 cm1) and the asymmetric as(CH2) (at 2862.9 cm1) are performed in dependence on the frequency and the strength of external electric fields and at varying temperature. The observed effects are interpreted as caused by orientation polarization of the OH and the adjacent CH2 moieties.
763

Investigation of different dielectric materials as gate insulator for MOSFETs

Oswal, Ritika 01 January 2014 (has links)
The scaling of semiconductor transistors has led to a decrease in thickness of the silicon dioxide layer used as gate dielectric. The thickness of the silicon dioxide layer is reduced to increase the gate capacitance, thus increasing the drain current. If the thickness of the gate dielectric decreases below 2nm, the leakage current due to the tunneling increases drastically. Hence it is necessary to replace the gate dielectric, silicon dioxide, with a physically thicker oxide layer of high-k materials like Hafnium oxide and Titanium oxide. High-k dielectric materials allow the capacitance to increase without a huge leakage current. Hafnium oxide and Titanium oxide films are deposited by reactive magnetron sputtering from Hafnium and Titanium targets respectively. These oxide layers are used to create metal-insulator-metal (MIM) structures using aluminum as the top and bottom electrodes. The films are deposited at various O2/Ar gas flow ratios, substrate temperatures, and process pressures. After attaining an exact recipe for these oxide layers that exhibit the desired parameters, MOS capacitors are fabricated with n-Si and p-Si substrates having aluminum electrodes at the top and bottom of each. Comparing the parameters of Hafnium oxide- and Titanium oxide- based MOS capacitors, MOSFET devices are designed with Hafnium oxide as gate dielectric.
764

Thermodynamic and Dynamic Behaviors of Self-Organizing Polymeric Systems

Zhao, Yiqiang January 2005 (has links)
No description available.
765

Enhanced Dielectric Properties of Micro and Nanolayered Films for Capacitor Applications

Mackey, Matthew E. 26 June 2012 (has links)
No description available.
766

Enhanced Dielectric Properties of Micro and Nanolayered Films for Capacitor Applications

Mackey, Matthew 26 June 2012 (has links)
No description available.
767

Effects of Dielectric Relaxation on Director Dynamics in Uniaxial Nematic Liquid Crystals

Gu, Mingxia 09 March 2009 (has links)
No description available.
768

The Development of DNA-Based Bio-Polymer Hybrid Thin Films for Capacitor Applications

Joyce, Donna Marie January 2013 (has links)
No description available.
769

Optical and Photovoltaic Properties of Copper Indium-Gallium Diselenide Materials and Solar Cells

Aryal, Puruswottam 19 December 2014 (has links)
No description available.
770

Structure-Property Studies of Substituted Azadipyrromethene-Based Dyes and High Dielectric Constant Polymers for Organic Electronic Applications

Pejic, Sandra 31 August 2018 (has links)
No description available.

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