Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Keyword
-
- College of Natual Science and Mathematics (3)
- Spectroscopy (3)
- Adaptive lens (2)
- Aligned array (2)
- Blue phase (2)
-
- Carbon nanotube (2)
- Electron transport (2)
- Infrared (2)
- Liquid crystal (2)
- Liquid crystal display (2)
- Low voltage (2)
- Organic electronics (2)
- Photometry (2)
- Scattering (2)
- Vcsel (2)
- 3d display (1)
- Adsorption (1)
- Al2o3 (1)
- Alumina (1)
- Anabaena (1)
- Anomalous plasma like collective oscillations (1)
- Antenna (1)
- Antenna radiation patterns (1)
- Asteroids (1)
- Astrometry (1)
- Astrophysical disk (1)
- Atomic force microscopy (1)
- Atomic physics (1)
- Attosecond (1)
- Au (1)
Articles 31 - 39 of 39
Full-Text Articles in Entire DC Network
Standoff Laser Interferometric Photoacoustic Spectroscopy For The Detection Of Explosives, Logan Marcus
Standoff Laser Interferometric Photoacoustic Spectroscopy For The Detection Of Explosives, Logan Marcus
Electronic Theses and Dissertations
There will unfortunately always be a pressing need to detect and identify explosive materials. Performing detection at a standoff distance is much safer and this is the impetus for this work. Photoacoustic spectroscopy is well suited to the task of explosive detection at a standoff distance. A detailed theory of the standoff measurement of the physical response of a system to photoacoustic excitation with an interferometric sensor has been constructed and tested. The use of this methodology to measure the standoff photoacoustic spectrum of TNT with an interferometric sensor has clearly been demonstrated. This methodology and the tested theory can …
Image Degradation Due To Surface Scattering In The Presence Of Aberrations, Narak Choi
Image Degradation Due To Surface Scattering In The Presence Of Aberrations, Narak Choi
Electronic Theses and Dissertations
This dissertation focuses on the scattering phenomena by well-polished optical mirror surfaces. Specifically, predicting image degradation by surface scatter from rough mirror surfaces for a two-mirror telescope operating at extremely short wavelengths (9nm~30nm) is performed. To evaluate image quality, surface scatter is predicted from the surface metrology data and the point spread function in the presence of both surface scatter and aberrations is calculated. For predicting the scattering intensity distribution, both numerical and analytic methods are considered. Among the numerous analytic methods, the small perturbation method (classical Rayleigh-Rice surface scatter theory), the Kirchhoff approximation method (classical BeckmanKirchhoff surface scatter theory), …
Infrared Tapered Slot Antennas Coupled To Tunnel Diodes, Louis A. Florence
Infrared Tapered Slot Antennas Coupled To Tunnel Diodes, Louis A. Florence
Electronic Theses and Dissertations
Tapered slot antennas (TSAs) have seen considerable application in the millimeter-wave portion of the spectrum. Desirable characteristics of TSAs include symmetric E- and H-plane antenna patterns, and broad non-resonant bandwidths. We investigate extension of TSA operation toward higher frequencies in the thermal infrared (IR), using a metal-oxide-metal diode as the detector. Several different infrared TSA design forms are fabricated using electronbeam lithography and specially developed thin-film processes. The angular antenna patterns of TSA-coupled diodes are measured at 10.6 micrometer wavelength in both E- and H-planes, and are compared to results of finite-element electromagnetic modeling using Ansoft HFSS. Parameter studies are …
Electronic Transport Investigation Of Chemically Derived Reduced Graphene Oxide Sheets, Daeha Joung
Electronic Transport Investigation Of Chemically Derived Reduced Graphene Oxide Sheets, Daeha Joung
Electronic Theses and Dissertations
Reduced graphene oxide (RGO) sheet, a chemically functionalized atomically thin carbon sheet, provides a convenient pathway for producing large quantities of graphene via solution processing. The easy processibility of RGO sheet and its composites offer interesting electronic, chemical and mechanical properties that are currently being explored for advanced electronics and energy based materials. However, a clear understanding of electron transport properties of RGO sheet is lacking which is of great significance for determining its potential application. In this dissertation, I demonstrate fabrication of high-yield solution based graphene field effects transistor (FET) using AC dielectrophoresis (DEP) and investigate the detailed electronic …
Phonon Modulation By Polarized Lasers For Material Modification, Sen-Yong Chen
Phonon Modulation By Polarized Lasers For Material Modification, Sen-Yong Chen
Electronic Theses and Dissertations
Magnetic resonance imaging (MRI) has become one of the premier non-invasive diagnostic tools, with around 60 million MRI scans applied each year. However, there is a risk of thermal injury due to radiofrequency (RF) induction heating of the tissue and implanted metallic device for the patients with the implanted metallic devices. Especially, MRI of the patients with implanted elongated devices such as pacemakers and deep brain stimulation systems is considered contraindicated. Many efforts, such as determining preferred MRI parameters, modifying magnetic field distribution, designing new structure and exploring new materials, have been made to reduce the induction heating. Improving the …
Lithographic Vertical-Cavity Surface-Emitting Lasers, Guowei Zhao
Lithographic Vertical-Cavity Surface-Emitting Lasers, Guowei Zhao
Electronic Theses and Dissertations
Remarkable improvements in vertical-cavity surface-emitting lasers (VCSELs) have been made by the introduction of mode- and current-confining oxide optical aperture now used commercially. However, the oxide aperture blocks heat flow inside the device, causing a larger thermal resistance, and the internal strain caused by the oxide can degrade device reliability, also the diffusion process used for the oxide formation can limit device uniformity and scalability. Oxide-free lithographic VCSELs are introduced to overcome these device limitations, with both the mode and current confined within the lithographically defined intracavity mesa, scaling and mass production of small size device could be possible. The …
High Pressure Micro-Spectroscopy Of Biological Assemblies And Cells, Sang Hoon Park
High Pressure Micro-Spectroscopy Of Biological Assemblies And Cells, Sang Hoon Park
Electronic Theses and Dissertations
Functional properties of living cells depend on the thermodynamic variables such as temperature and pressure. A unique tool to investigate volume effects on structure and metabolism of the cell and biomolecules is pressure perturbation. We have developed a new setup that enables micro-spectroscopy and optical imaging of individual live cells at variable pressure from 0.1 to 400 MPa. Following characterization of the setup, pressure and temperature effects on the secondary structure of the peptide Poly-L-glutamic acid (PGA) in deuterated water buffer solution were investigated. The amide I band of PGA is sensitive to pressure and temperature, and by spectral deconvolution, …
Radiation Effects On Wide Band Gap Semiconductor Transport Properties, Casey Minna Schwarz
Radiation Effects On Wide Band Gap Semiconductor Transport Properties, Casey Minna Schwarz
Electronic Theses and Dissertations
In this research, the transport properties of ZnO were studied through the use of electron and neutron beam irradiation. Acceptor states are known to form deep in the bandgap of doped ZnO material. By subjecting doped ZnO materials to electron and neutron beams we are able to probe, identify and modify transport characteristics relating to these deep accepter states. The impact of irradiation and temperature on minority carrier diffusion length and lifetime were monitored through the use of the Electron Beam Induced Current (EBIC) method and Cathodoluminescence (CL) spectroscopy. The minority carrier diffusion length, L, was shown to increase as …
Spin Pumping In Lateral Double Quantum Dot Systems, Sabine S. Pelton
Spin Pumping In Lateral Double Quantum Dot Systems, Sabine S. Pelton
Electronic Theses and Dissertations
Electron transport in single lateral quantum dot (QD) and parallel lateral double quantum dot (DQD) systems is modeled using semiclassical rate equations. The Zeeman effect, in conjunction with resonant tunneling, is used to select the spin of electrons involved in transport. We show adiabatic spin pumping by periodic variation of the systems' confining parameters, namely the quantum point contacts (QPCs) dictating the boundaries of the dots, and the gate voltage applied to each dot. The limitations of adiabatic spin pumping are subsequently examined by counting the average spin pumped per cycle when frequency and interdot capacitance are adjusted.