Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 19 of 19 for “"DBRs"”.
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Design, growth and optimization of 2-μm InGaSb/AlGaSb quantum well based VECSELs on GaAs/AlGaAs DBRs.
… on AlAsSb/GaSb distributed Bragg reflectors (DBRs), grown latticematched on GaSb substrates. In this work the ability to grow such antimonide VECSEL structures on GaAs substrates is explored. The growth of such III-Sb VECSELs on GaAs substrates is non-trivial due to the 7.78% lattice mismatch …
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Assessment of Diabetes Regimen Disease Care in Youth with Type 1 Diabetes via the Diabetes Behavior Rating Scale and the 24-Hour Diabetes Interview
… care, the Diabetes Behavior Rating Scale (DBRS) and the 24-hr Diabetes Interview (24-hr) were evaluated. The 24-hr is a widely used, structured interview while the DBRS is a self-administered, fixed-choice questionnaire. Both measures were administered to 250 youth with Type 1 Diabetes …
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Biogeochemistry of denitrifying bioreactors to enhance phosphorus removal from agricultural subsurface drainage
… in surface waters. Denitrifying bioreactors (DBRs) are a prominent edge-of-field treatment technology to mitigate surface water nitrate loadings from agricultural subsurface drainage. Recent studies have identified that subsurface drainage can also contribute to the loss of phosphorus from …
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Design and Fabrication of Long -Wavelength Vertical -Cavity Surface -Emitting Lasers Using Wafer Bonding Technologies
… substrates with high-contrast composite DBRs for a better performance, and therefore the need to grow thick epitaxial DBRs is eliminated. During the process development, substrate-independent DBRs such as polycrystalline-GaAs/Al-oxide, amorphous Si/Al-oxide, Si/Mg-oxide, and …
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Tomographic reconstruction and sub-surface imaging of porous nitride semiconductors
… through porous GaN distributed Bragg reflectors (DBRs), highly-reflective and wavelength-selective mirrors for optoelectronic device applications such as next-generation micro light emitting diode (LED) displays. These photonic structures are fabricated through metal-organic vapour phase epitaxy …
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Impulsività e Sindrome di Down
… utilizzata la Disruptive Behavior Rating Scale (DBRS), teacher version. Sono stati esaminati 68 soggetti, di età compresa tra 18 e 51 anni (QI complessivo medio=33,81). Sono emersi punteggi alla DBRS significativamente maggiori rispetto al cut off della scala, senza una correlazione tra il …
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Self-heating control of edge emitting and vertical cavity surface emitting lasers
… Removing the oxide layer and using AlAs in the DBRs leads to record low thermal resistance. Optimization of the DBRs leads to low resistance and low free carrier absorption. Power conversion efficiency higher than 50% is achieved. To further reduce device voltage and heat generation, the …
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Development of Nanostructured Light Emitters in Gallium Nitride
… QWs with porous distributed Bragg reflectors (DBRs) is reported, with a corresponding increase in LED efficiency owing to improved light extraction. Porous DBRs are also integrated with InGaN QDs to create prototype optical cavity structures, combined with a vertical etching process to create …
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Design and Characterization of Integrated Photonic Devices Fabricated Using Selective-Area Epitaxy and Distributed Bragg Reflector Surface Gratings
… devices using distributed Bragg reflectors (DBRs). In this dissertation, ridge-waveguide DBR lasers with first-order surface gratings are investigated. These lasers exhibit low thresholds (6 mA), high slope efficiencies (0.46 W/A), and single-frequency operation with narrow linewidths ($<$25 …
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Compliant Epitaxy of Iii-V Compound Semiconductors for Optoelectronic Device Applications
… oxidized AlAs materials, substrate independent DBRs were fabricated at wavelengths in both the visible spectrum, 480 nm to 550 nm, as well as those used in the telecommunications industry, 1310 nm to 1550 nm. In addition, VLTMBE-grown InGaP was used as a protection layer during post-growth …
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Comparative Validity of MMPI-A Scales Scores in African American and Caucasian Male Juvenile Delinquents
… 1991; Achenbach & Rescorla, 2001) and DBRS (Barkley & Murphy, 1998), which were used as extra-test measures. Significant overall prediction bias was detected in 15 out of 56 regressions. Statistically significant prediction bias was found for a subset of criterion variables for Clinical …
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Áhrif viðbótargreininga á meðferð barna með mótþróaþrjóskuröskun
… úrræði. Einkenni mótþróaþrjóskuröskunar (DBRS) og tíðni og alvarleiki hegðunarvanda (HSQ) var mælt við upphaf og lok meðferðar. Einkenni mótþróaþrjóskuröskunar minnkuðu, ásamt tíðni og alvarleika hegðunarvanda hjá hópnum í heild og hjá þeim sem voru með og án viðbótargreiningar. Ekki …
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Selective mode coupling in microring resonators for single mode semiconductor lasers
… reflectors such as distributed Bragg reflectors (DBRs) and sampled grating distributed Bragg reflectors (SGDBRs). Compact, narrowband reflectors with high reflectivities are of interest to replace the commonly used DBRs and SGDBRs. This thesis presents our work on the simulation, design, …
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Clustering of Behavioral Data for Identification of Presumptive Subtypes of Attention Deficit/Hyperactivity Disorder in Children
… Data from behavioral checklist (CBCL and DBRS-IV) were matched to Amen's Subtype Symptom Checklist and each subject was given a percentage score for six subtype symptoms. Cluster analysis reliably found six clusters and each subject was labeled according to their symptom presentation. The …
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Micro- and nano-soft lithography for the fabrication of photonic devices
… acted as Distributed Bragg Reflectors (DBRs).Key advantages for the techniques used throughout this thesis are that they allow the patterning of sensitive materials that otherwise would not survive classical lithography due to aggressive chemical treatment or high UV exposure. In …
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Design and operation of Low Frequency AC (LFAC) transmission system for connecting offshore wind farms
… limits. Also, depending on the system rating, DBRs may need to be applied in the DC sides of the OWTGs and the onshore BtB frequency converters.
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Modeling of Bragg reflectors to increase performance of high efficiency III-V multijunction solar cells
High efficiency III-V solar cells are important for solar concentrator systems and space applications. To increase the efficiency of these cells, creative methods have been employed such as adding quantum wells in stress-balanced superlatticies to get closer to the ideal bandgaps for three junction …
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Crecimiento de nitruros del grupo III por epitaxia de haces moleculares para la fabricación de diodos electroluminiscentes en el rango visible-ultravioleta
… InAlN/GaN distributed Bragg reflectors (DBRs) with peak reflectivity values up to 60 % at 400 nm. The studies presented in this thesis about In incorporation into (0001) InAlN show that it decreases with both growth temperature and impinging Al/Ga flux ratio. The crystal quality of …
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GaAs-based quantum well and quantum dot light-emitting diodes and lasers for 1.3 and 1.55 um emission
… temperature of the distributed Bragg reflectors (DBRs) which define the cavity, and as a function of the alloying of the electrical contacts. It is found that the external efficiency, rjext, and the full width at half maximum (FWHM) of the EL peak degrade as the DBR growth temperature decreases in …