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Articles 1 - 17 of 17
Full-Text Articles in Engineering
Tunable Electronic Structure Via Dna-Templated Heteroaggregates Of Two Distinct Cyanine Dyes, Jonathan S. Huff, Matthew S. Barclay, Azhad U. Chowdhury, Lance K. Patten, Simon K. Roy, Aaron Sup, Austin Biaggne, Lan Li, Jeunghoon Lee, Paul H. Davis, Bernard Yurke, William B. Knowlton, Daniel B. Turner, Ryan D. Pensack
Tunable Electronic Structure Via Dna-Templated Heteroaggregates Of Two Distinct Cyanine Dyes, Jonathan S. Huff, Matthew S. Barclay, Azhad U. Chowdhury, Lance K. Patten, Simon K. Roy, Aaron Sup, Austin Biaggne, Lan Li, Jeunghoon Lee, Paul H. Davis, Bernard Yurke, William B. Knowlton, Daniel B. Turner, Ryan D. Pensack
Materials Science and Engineering Faculty Publications and Presentations
Molecular excitons are useful for applications in light harvesting, organic optoelectronics, and nanoscale computing. Electronic energy transfer (EET) is a process central to the function of devices based on molecular excitons. Achieving EET with a high quantum efficiency is a common obstacle to excitonic devices, often owing to the lack of donor and acceptor molecules that exhibit favorable spectral overlap. EET quantum efficiencies may be substantially improved through the use of heteroaggregates─aggregates of chemically distinct dyes─rather than individual dyes as energy relay units. However, controlling the assembly of heteroaggregates remains a significant challenge. Here, we use DNA Holliday junctions to …
Molecular Dynamics Simulations Of Cyanine Dimers Attached To Dna Holliday Junctions, Austin Biaggne, Young C. Kim, Joseph S. Melinger, William B. Knowlton, Bernard Yurke, Lan Li
Molecular Dynamics Simulations Of Cyanine Dimers Attached To Dna Holliday Junctions, Austin Biaggne, Young C. Kim, Joseph S. Melinger, William B. Knowlton, Bernard Yurke, Lan Li
Materials Science and Engineering Faculty Publications and Presentations
Dye aggregates and their excitonic properties are of interest for their applications to organic photovoltaics, non-linear optics, and quantum information systems. DNA scaffolding has been shown to be effective at promoting the aggregation of dyes in a controllable manner. Specifically, isolated DNA Holliday junctions have been used to achieve strongly coupled cyanine dye dimers. However, the structural properties of the dimers and the DNA, as well as the role of Holliday junction isomerization are not fully understood. To study the dynamics of cyanine dimers in DNA, molecular dynamics simulations were carried out for adjacent and transverse dimers attached to Holliday …
Oblique Packing And Tunable Excitonic Coupling In Dna-Templated Squaraine Rotaxane Dimer Aggregates, Matthew S. Barclay, Christopher K. Wilson, Simon K. Roy, Olga A. Mass, Azhad U. Chowdhury, Jonathan S. Huff, Daniel B. Turner, Paul H. Davis, Bernard Yurke, William B. Knowlton, Jeunghoon Lee, Ryan D. Pensack
Oblique Packing And Tunable Excitonic Coupling In Dna-Templated Squaraine Rotaxane Dimer Aggregates, Matthew S. Barclay, Christopher K. Wilson, Simon K. Roy, Olga A. Mass, Azhad U. Chowdhury, Jonathan S. Huff, Daniel B. Turner, Paul H. Davis, Bernard Yurke, William B. Knowlton, Jeunghoon Lee, Ryan D. Pensack
Materials Science and Engineering Faculty Publications and Presentations
When molecules are aggregated such that their excited states form delocalized excitons, their spatial arrangement, or packing, can be coarsely controlled by templating and finely controlled by chemical substitution; however, challenges remain in controlling their packing on intermediate length scales. Here, we use an approach based on mechanically interlocked molecules to promote an elusive oblique packing arrangement in a series of three squaraine rotaxane dimers. We template the squaraine rotaxane dimers using DNA and observe two excitonically split bands of near-equal intensity in their absorption spectra – a distinct signature of oblique packing, validated by theoretical modeling of the experimental …
Characterizing Mode Anharmonicity And Huang–Rhys Factors Using Models Of Femtosecond Coherence Spectra, Matthew S. Barclay, Jonathan S. Huff, Ryan D. Pensack, Paul H. Davis, William B. Knowlton, Bernard Yurke, Jacob C. Dean, Paul C. Arpin, Daniel B. Turner
Characterizing Mode Anharmonicity And Huang–Rhys Factors Using Models Of Femtosecond Coherence Spectra, Matthew S. Barclay, Jonathan S. Huff, Ryan D. Pensack, Paul H. Davis, William B. Knowlton, Bernard Yurke, Jacob C. Dean, Paul C. Arpin, Daniel B. Turner
Materials Science and Engineering Faculty Publications and Presentations
Femtosecond laser pulses readily produce coherent quantum beats in transient–absorption spectra. These oscillatory signals often arise from molecular vibrations and therefore may contain information about the excited-state potential energy surface near the Franck–Condon region. Here, by fitting the measured spectra of two laser dyes to microscopic models of femtosecond coherence spectra (FCS) arising from molecular vibrations, we classify coherent quantum-beat signals as fundamentals or overtones and quantify their Huang–Rhys factors and anharmonicity values. We discuss the extracted Huang–Rhys factors in the context of quantum-chemical computations. This work solidifies the use of FCS for analysis of coherent quantum beats arising from …
Data-Driven And Multiscale Modeling Of Dna-Templated Dye Aggregates, Austin Biaggne, Lawrence Spear, German Barcenas, Maia Ketteridge, William B. Knowlton, Bernard Yurke, Lan Li
Data-Driven And Multiscale Modeling Of Dna-Templated Dye Aggregates, Austin Biaggne, Lawrence Spear, German Barcenas, Maia Ketteridge, William B. Knowlton, Bernard Yurke, Lan Li
Materials Science and Engineering Faculty Publications and Presentations
Dye aggregates are of interest for excitonic applications, including biomedical imaging, organic photovoltaics, and quantum information systems. Dyes with large transition dipole moments (μ) are necessary to optimize coupling within dye aggregates. Extinction coefficients (ε) can be used to determine the μ of dyes, and so dyes with a large ε (>150,000 M−1) should be engineered or identified. However, dye properties leading to a large ε are not fully understood, and low-throughput methods of dye screening, such as experimental measurements or density functional theory (DFT) calculations, can be time-consuming. In order to screen large datasets of molecules …
Real Time Audio Processing Using A Low-Power Digital Signal Processor, Aaron Norlinger
Real Time Audio Processing Using A Low-Power Digital Signal Processor, Aaron Norlinger
Honors Theses
This project focused on the creation of a series of audio processing functions that could run in real time on the ezDSP5502 processor. The Digital Signal Processor (DSP) being used for this project is an industry standard for lowpower signal processing applications. The overall goal was to have a code base that could sample audio in real time from any source, filter it in a variety of ways, run a Fast Fourier Transform on the audio, display the resulting frequency data to an LCD screen, and then output the filtered audio to an external speaker. This general process is used …
An Analytical Methodology To Security Constraints Management In Power System Operation, Shubo Zhang
An Analytical Methodology To Security Constraints Management In Power System Operation, Shubo Zhang
ETD Archive
In a deregulated electricity market, Independent System Operators (ISOs) are responsible for dispatching power to the load securely, efficiently, and economically. ISO performs Security Constrained Unit Commitment (SCUC) to guarantee sufficient generation commitment, maximized social welfare and facilitating market-driven economics. A large number of security constraints would render the model impossible to solve under time requirements. Developing a method to identify the minimum set of security constraints without overcommitting is necessary to reduce Mixed Integer Linear Programming (MILP) solution time. To overcome this challenge, we developed a powerful tool called security constraint screening. The proposed approach effectively filters out non-dominating …
Tuning Between Quenching And Energy Transfer In Dna-Templated Heterodimer Aggregates, Azhad U. Chowdhury, Jonathan S. Huff, Matthew S. Barclay, Lance K. Patten, Aaron Sup, Natalya Hallstrom, Jeunghoon Lee, Paul H. Davis, Daniel B. Turner, Bernard Yurke, William B. Knowlton, Ryan D. Pensack
Tuning Between Quenching And Energy Transfer In Dna-Templated Heterodimer Aggregates, Azhad U. Chowdhury, Jonathan S. Huff, Matthew S. Barclay, Lance K. Patten, Aaron Sup, Natalya Hallstrom, Jeunghoon Lee, Paul H. Davis, Daniel B. Turner, Bernard Yurke, William B. Knowlton, Ryan D. Pensack
Materials Science and Engineering Faculty Publications and Presentations
Molecular excitons, which propagate spatially via electronic energy transfer, are central to numerous applications including light harvesting, organic optoelectronics, and nanoscale computing; they may also benefit applications such as photothermal therapy and photoacoustic imaging through the local generation of heat via rapid excited-state quenching. Here we show how to tune between energy transfer and quenching for heterodimers of the same pair of cyanine dyes by altering their spatial configuration on a DNA template. We assemble “transverse” and “adjacent” heterodimers of Cy5 and Cy5.5 using DNA Holliday junctions. We find that the transverse heterodimers exhibit optical properties consistent with excitonically interacting …
Exciton Delocalization In A Dna-Templated Organic Semiconductor Dimer Assembly, Xiao Wang, Ruojie Sha, William B. Knowlton, Nadrian C. Seeman, James W. Canary, Bernard Yurke
Exciton Delocalization In A Dna-Templated Organic Semiconductor Dimer Assembly, Xiao Wang, Ruojie Sha, William B. Knowlton, Nadrian C. Seeman, James W. Canary, Bernard Yurke
Materials Science and Engineering Faculty Publications and Presentations
A chiral dimer of an organic semiconductor was assembled from octaniline (octamer of polyaniline) conjugated to DNA. Facile reconfiguration between the monomer and dimer of octaniline–DNA was achieved. The geometry of the dimer and the exciton coupling between octaniline molecules in the assembly was studied both experimentally and theoretically. The octaniline dimer was readily switched between different electronic states by protonic doping and exhibited a Davydov splitting comparable to those previously reported for DNA–dye systems employing dyes with strong transition dipoles. This approach provides a possible platform for studying the fundamental properties of organic semiconductors with DNA-templated assemblies, which serve …
Reconfigurable Array Control Via Convolutional Neural Networks, Garrett A. Harris
Reconfigurable Array Control Via Convolutional Neural Networks, Garrett A. Harris
Browse all Theses and Dissertations
A method for the beam forming control of an array of reconfigurable antennas is presented. The method consists of using two parallel convolutional neural networks (CNNs) to analyze a desired radiation pattern image, or mask, and provide a suggestion for the reconfigurable element state, array shape, and steering weights necessary to obtain the radiation pattern. This research compares beam forming systems designed for three distinct element types: a patch antenna, a reconfigurable square spiral antenna restricted to a single reconfigurable state, and the fully reconfigurable square spiral. The parametric sweeps for the design of the CNNs are presented along with …
Unit Circle Roots Based Sensor Array Signal Processing, Jared P. Smith
Unit Circle Roots Based Sensor Array Signal Processing, Jared P. Smith
Browse all Theses and Dissertations
As technology continues to rapidly evolve, the presence of sensor arrays and the algorithms processing the data they generate take an ever-increasing role in modern human life. From remote sensing to wireless communications, the importance of sensor signal processing cannot be understated. Capon's pioneering work on minimum variance distortionless response (MVDR) beamforming forms the basis of many modern sensor array signal processing (SASP) algorithms. In 2004, Steinhardt and Guerci proved that the roots of the polynomial corresponding to the optimal MVDR beamformer must lie on the unit circle, but this result was limited to only the MVDR. This dissertation contains …
Cmos Wide Tuning Gilbert Mixer With Controllable If Bandwidth In Upcoming Rf Front End For Multi-Band Multi-Standard Applications, Jianfeng Ren
Browse all Theses and Dissertations
The current global system for mobile communications, wireless local area, Bluetooth, and ultra-wideband demands a multi-band/multi-standard RF front end that can access all the available bandwidth specifications. Trade-offs occur between power consumption, noise figure, and linearity in CMOS Gilbert mixer wide tuning designs. Besides, it is preferable to have a constant IF bandwidth for different gain settings as the bandwidth varies with the load impedance when an RF receiver is tuned to a higher frequency. My dissertation consists of three parts. First, a tunable constant IF bandwidth Gilbert mixer is introduced for multi-band standard wireless applications such as 802.11 a/b/g …
Demonstration Of High-Temperature Operation Of Beta-Gallium Oxide (Β-Ga2o3) Metal-Oxide-Semiconductor Field Effect Transistors (Mosfet) With Electrostatic Model In Comsol, Nicholas Paul Sepelak
Demonstration Of High-Temperature Operation Of Beta-Gallium Oxide (Β-Ga2o3) Metal-Oxide-Semiconductor Field Effect Transistors (Mosfet) With Electrostatic Model In Comsol, Nicholas Paul Sepelak
Browse all Theses and Dissertations
β-Ga2O3 is a robust semiconductor material set with a large band gap of ~4.8 eV, low intrinsic carrier concentration, and high melting point that offers a stable platform for operating electronic devices at high temperatures and extreme environments. The first half of this thesis will cover the fabrication of a fixture and packaging to test electronic components at high temperatures. Then it will highlight the characterization of β-Ga2O3 field effect transistors from room temperature (RT) up to 500 °C. The devices, fabricated with Ni/Au and Al2O3 gate metal-oxide-semiconductor (MOS), demonstrate stable operation up to 500 oC. The tested device shows …
Quadrature Phase-Domain Adpll With Integrated On-Line Amplitude Locked Loop Calibration For 5g Multi-Band Applications, Xiaomeng Zhang
Quadrature Phase-Domain Adpll With Integrated On-Line Amplitude Locked Loop Calibration For 5g Multi-Band Applications, Xiaomeng Zhang
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5th generation wireless systems (5G) have expanded frequency band coverage with the low-band 5G and mid-band 5G frequencies spanning 600 MHz to 4 GHz spectrum. This dissertation focuses on a microelectronic implementation of CMOS 65 nm design of an All-Digital Phase Lock Loop (ADPLL), which is a critical component for advanced 5G wireless transceivers. The ADPLL is designed to operate in the frequency bands of 600MHz-930MHz, 2.4GHz-2.8GHz and 3.4GHz-4.2GHz. Unique ADPLL sub-components include: 1) Digital Phase Frequency Detector, 2) Digital Loop Filter, 3) Channel Bank Select Circuit, and 4) Digital Control Oscillator. Integrated with the ADPLL is a 90-degree active …
Amygdala Modeling With Context And Motivation Using Spiking Neural Networks For Robotics Applications, Matthew Aaron Zeglen
Amygdala Modeling With Context And Motivation Using Spiking Neural Networks For Robotics Applications, Matthew Aaron Zeglen
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Cognitive capabilities for robotic applications are furthered by developing an artificial amygdala that mimics biology. The amygdala portion of the brain is commonly understood to control mood and behavior based upon sensory inputs, motivation, and context. This research builds upon prior work in creating artificial intelligence for robotics which focused on mood-generated actions. However, recent amygdala research suggests a void in greater functionality. This work developed a computational model of an amygdala, integrated this model into a robot model, and developed a comprehensive integration of the robot for simulation, and live embodiment. The developed amygdala, instantiated in the Nengo Brain …
Fault-Tolerant Control Of Autonomous Ground Vehicle Under Actuator And Sensor, Vaishnavi Janakiraman
Fault-Tolerant Control Of Autonomous Ground Vehicle Under Actuator And Sensor, Vaishnavi Janakiraman
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Unmanned ground vehicles have a wide range of potential applications including autonomous driving, military surveillance, emergency responses, and agricultural robotics, etc. Since such autonomous vehicles need to operate reliably at all times, despite the possible occurrence of faulty behaviors in some system components, the development of fault-tolerant control schemes is a crucial step in ensuring reliable and safe operations. In this research, a fault-tolerant control scheme is developed for a nonlinear ground vehicle model with possible occurrence of both actuator faults in the form of loss of effectiveness (LOE) and sensor bias faults. Based on the vehicle and fault models …
Low-Power, Low-Cost, & High-Performance Digital Designs : Multi-Bit Signed Multiplier Design Using 32nm Cmos Technology, N V Vijaya Krishna Boppana
Low-Power, Low-Cost, & High-Performance Digital Designs : Multi-Bit Signed Multiplier Design Using 32nm Cmos Technology, N V Vijaya Krishna Boppana
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Binary multipliers are ubiquitous in digital hardware. Digital multipliers along with the adders play a major role in computing, communicating, and controlling devices. Multipliers are used majorly in the areas of digital signal and image processing, central processing unit (CPU) of the computers, high-performance and parallel scientific computing, machine learning, physical layer design of the communication equipment, etc. The predominant presence and increasing demand for low-power, low-cost, and high-performance digital hardware led to this work of developing optimized multiplier designs. Two optimized designs are proposed in this work. One is an optimized 8 x 8 Booth multiplier architecture which is …