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University of Nebraska - Lincoln

Department of Electrical and Computer Engineering: Faculty Publications

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A High-Density Theta Burst Paradigm Enhances The Aftereffects Of Transcranial Magnetic Stimulation: Evidence From Focal Stimulation Of Rat Motor Cortex, Qinglei Meng, Hieu Nguyen, Antonia Vrana, Simone Baldwin, Charlotte Qiong Li, Antonia Giles, Jun Wang, Yihong Yang, Hanbing Lu May 2022

A High-Density Theta Burst Paradigm Enhances The Aftereffects Of Transcranial Magnetic Stimulation: Evidence From Focal Stimulation Of Rat Motor Cortex, Qinglei Meng, Hieu Nguyen, Antonia Vrana, Simone Baldwin, Charlotte Qiong Li, Antonia Giles, Jun Wang, Yihong Yang, Hanbing Lu

Department of Electrical and Computer Engineering: Faculty Publications

Background: Theta burst stimulation (TBS) is an efficient noninvasive neuromodulation paradigm that has been widely adopted, clinically. However, the efficacy of TBS treatment remains similarly modest as conventional 10 Hz repetitive transcranial magnetic stimulation (rTMS).

Objective/hypothesis: To develop a new TBS paradigm that enhances the effects of TMS administration while maintaining high time-efficiency.

Methods: We describe here a new TMS paradigm, named High-Density Theta Burst Stimulation (hdTBS). This paradigm delivers up to 6 pulses per burst, as opposed to only 3 in conventional TBS, while maintaining the inter-burst interval of 200 ms (or 5 Hz) - a …


Queueing Theory Model Of Pentose Phosphate Pathway, Sylwester M. Kloska, Krzysztof Pałczyński, Tomasz Marciniak, Tomasz Talaśka, Marissa Miller, Beata J. Wysocki, Paul H. Davis, Tadeusz A. Wysocki Mar 2022

Queueing Theory Model Of Pentose Phosphate Pathway, Sylwester M. Kloska, Krzysztof Pałczyński, Tomasz Marciniak, Tomasz Talaśka, Marissa Miller, Beata J. Wysocki, Paul H. Davis, Tadeusz A. Wysocki

Department of Electrical and Computer Engineering: Faculty Publications

Due to its role in maintaining the proper functioning of the cell, the pentose phosphate pathway (PPP) is one of the most important metabolic pathways. It is responsible for regulating the concentration of simple sugars and provides precursors for the synthesis of amino acids and nucleotides. In addition, it plays a critical role in maintaining an adequate level of NADPH, which is necessary for the cell to fight oxidative stress. These reasons prompted the authors to develop a computational model, based on queueing theory, capable of simulating changes in PPP metabolites’ concentrations. The model has been validated with empirical data …


A Precise Dispenser Design For Canine Cognition Research, Walker Arce, Jeffrey R. Stevens Feb 2022

A Precise Dispenser Design For Canine Cognition Research, Walker Arce, Jeffrey R. Stevens

Department of Electrical and Computer Engineering: Faculty Publications

Some forms of canine cognition research require a dispenser that can accurately dispense precise quantities of treats. When using off-the-shelf or retrofitted dispensers, there is no guarantee that a precise number of treats will be dispensed. Often, they will over-dispense treats, which may not be acceptable for some tasks. Here we describe a 3D-printed precise treat dispenser with a 59-treat capacity driven by a stepper motor drive and controlled by an integrated Raspberry Pi. The dispenser can be built for less than 200 USD and is fully 3D printable. While off-the-shelf dispensers can result in an error rate of 20–30%, …


Infrared Dielectric Functions And Brillouin Zone Center Phonons Of Α-Ga2O3 Compared To Α-Al2O3, Megan Stokey, Rafal Korlacki, Matthew J. Hilfiker, Sean Knight, Steffen Richter, Vanya Darakchieva, Riena Jinno, Yongjin Cho, Huili Grace Xing, Debdeep Jena, Yuichi Oshima, Kamruzzaman Khan, Elaheh Ahmadi, Mathias Schubert Jan 2022

Infrared Dielectric Functions And Brillouin Zone Center Phonons Of Α-Ga2O3 Compared To Α-Al2O3, Megan Stokey, Rafal Korlacki, Matthew J. Hilfiker, Sean Knight, Steffen Richter, Vanya Darakchieva, Riena Jinno, Yongjin Cho, Huili Grace Xing, Debdeep Jena, Yuichi Oshima, Kamruzzaman Khan, Elaheh Ahmadi, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

We determine the anisotropic dielectric functions of rhombohedral α-Ga2O3 by far-infrared and infrared generalized spectroscopic ellipsometry and derive all transverse optical and longitudinal optical phonon mode frequencies and broadening parameters. We also determine the high-frequency and static dielectric constants. We perform density functional theory computations and determine the phonon dispersion for all branches in the Brillouin zone, and we derive all phonon mode parameters at the Brillouin zone center including Raman-active, infrared-active, and silent modes. Excellent agreement is obtained between our experimental and computation results as well as among all previously reported partial information from experiment …


Nanomechanical Resonators: Toward Atomic Scale, Bo Xu, Pengcheng Zhang, Jiankai Zhu, Zuheng Liu, Alexander Eichler, Xu-Qian Zheng, Jaesung Lee, Aneesh Dash, Swapnil More, Song Wu, Yanan Yanan, Hao Jia, Akshay Naik, Adrian Bachtold, Rui Yang, Philip X.-L. Feng, Zenghui Wang Jan 2022

Nanomechanical Resonators: Toward Atomic Scale, Bo Xu, Pengcheng Zhang, Jiankai Zhu, Zuheng Liu, Alexander Eichler, Xu-Qian Zheng, Jaesung Lee, Aneesh Dash, Swapnil More, Song Wu, Yanan Yanan, Hao Jia, Akshay Naik, Adrian Bachtold, Rui Yang, Philip X.-L. Feng, Zenghui Wang

Department of Electrical and Computer Engineering: Faculty Publications

The quest for realizing and manipulating ever smaller man-made movable structures and dynamical machines has spurred tremendous endeavors, led to important discoveries, and inspired researchers to venture to new grounds. Scientific feats and technological milestones of miniaturization of mechanical structures have been widely accomplished by advances in machining and sculpturing ever shrinking features out of bulk materials such as silicon. With the flourishing multidisciplinary field of low-dimensional nanomaterials, including one-dimensional (1D) nanowires/nanotubes, and two-dimensional (2D) atomic layers such as graphene/phosphorene, growing interests and sustained efforts have been devoted to creating mechanical devices toward the ultimate limit of miniaturization— genuinely down …


Serum Protein Signatures Using Aptamer-Based Proteomics For Minimal Change Disease And Membranous Nephropathy, Daniel A. Muruve, Hanna Debiec, Simon T. Dillon, Xuesong Gu, Emmanuelle Plaisier, Handan Can, Hasan H. Otu, Towia A. Libermann, Pierre Ronco Jan 2022

Serum Protein Signatures Using Aptamer-Based Proteomics For Minimal Change Disease And Membranous Nephropathy, Daniel A. Muruve, Hanna Debiec, Simon T. Dillon, Xuesong Gu, Emmanuelle Plaisier, Handan Can, Hasan H. Otu, Towia A. Libermann, Pierre Ronco

Department of Electrical and Computer Engineering: Faculty Publications

Introduction: Minimal change disease (MCD) and membranous nephropathy (MN) are glomerular diseases (glomerulonephritis [GN]) that present with the nephrotic syndrome. Although circulating PLA2R antibodies have been validated as a biomarker for MN, the diagnosis of MCD and PLA2R-negative MN still relies on the results of kidney biopsy or empirical corticosteroids in children. We aimed to identify serum protein biomarker signatures associated with MCD and MN pathogenesis using aptamer-based proteomics.

Methods: Quantitative SOMAscan proteomics was applied to the serum of adult patients with MCD (n = 15) and MN(n = 37) and healthy controls (n = …


Multilayer Lateral Heterostructures Of Van Der Waals Crystals With Sharp, Carrier–Transparent Interfaces, Eli A. Sutter, Raymond R. Unocic, Juan-Carlos Idrobo, Peter Sutter Nov 2021

Multilayer Lateral Heterostructures Of Van Der Waals Crystals With Sharp, Carrier–Transparent Interfaces, Eli A. Sutter, Raymond R. Unocic, Juan-Carlos Idrobo, Peter Sutter

Department of Electrical and Computer Engineering: Faculty Publications

Research on engineered materials that integrate different 2D crystals has largely focused on two prototypical heterostructures: Vertical van der Waals stacks and lateral heterostructures of covalently stitched monolayers. Extending lateral integration to few layer or even multilayer van der Waals crystals could enable architectures that combine the superior light absorption and photonic properties of thicker crystals with close proximity to interfaces and efficient carrier separation within the layers, potentially benefiting applications such as photovoltaics. Here, the realization of multilayer heterstructures of the van der Waals semiconductors SnS and GeS with lateral interfaces spanning up to several hundred individual layers is …


Cybert: Cybersecurity Claim Classification By Fine-Tuning The Bert Language Model, Kimia Ameri, Michael Hempel, Hamid Sharif, Juan Lopez Jr., Kalyan Perumalla Nov 2021

Cybert: Cybersecurity Claim Classification By Fine-Tuning The Bert Language Model, Kimia Ameri, Michael Hempel, Hamid Sharif, Juan Lopez Jr., Kalyan Perumalla

Department of Electrical and Computer Engineering: Faculty Publications

We introduce CyBERT, a cybersecurity feature claims classifier based on bidirectional encoder representations from transformers and a key component in our semi-automated cybersecurity vetting for industrial control systems (ICS). To train CyBERT, we created a corpus of labeled sequences from ICS device documentation collected across a wide range of vendors and devices. This corpus provides the foundation for fine-tuning BERT’s language model, including a prediction-guided relabeling process. We propose an approach to obtain optimal hyperparameters, including the learning rate, the number of dense layers, and their configuration, to increase the accuracy of our classifier. Fine-tuning all hyperparameters of the resulting …


Use Of Average Mutual Information And Derived Measures To Find Coding Regions, Garin Newcomb, Khalid Sayood Oct 2021

Use Of Average Mutual Information And Derived Measures To Find Coding Regions, Garin Newcomb, Khalid Sayood

Department of Electrical and Computer Engineering: Faculty Publications

One of the important steps in the annotation of genomes is the identification of regions in the genome which code for proteins. One of the tools used by most annotation approaches is the use of signals extracted from genomic regions that can be used to identify whether the region is a protein coding region. Motivated by the fact that these regions are information bearing structures we propose signals based on measures motivated by the average mutual information for use in this task. We show that these signals can be used to identify coding and noncoding sequences with high accuracy. We …


Near-Field Imaging Of Plasmonic Nanopatch Antennas With Integrated Semiconductor Quantum Dots, Vasudevan Iyer, Yoong Sheng Phang, Andrew Butler, Jiyang Chen, Brian Lerner, Christos Argyropoulos, Thang Hoang, Benjamin Lawrie Oct 2021

Near-Field Imaging Of Plasmonic Nanopatch Antennas With Integrated Semiconductor Quantum Dots, Vasudevan Iyer, Yoong Sheng Phang, Andrew Butler, Jiyang Chen, Brian Lerner, Christos Argyropoulos, Thang Hoang, Benjamin Lawrie

Department of Electrical and Computer Engineering: Faculty Publications

Plasmonic nanopatch antennas that incorporate dielectric gaps hundreds of picometers to several nanometers thick have drawn increasing attention over the past decade because they confine electromagnetic fields to grossly sub-diffraction-limited volumes. Substantial control over the optical properties of excitons and color centers confined within these plasmonic cavities has already been demonstrated with far-field optical spectroscopies, but near-field optical spectroscopies are essential for an improved understanding of the plasmon–emitter interaction at the nanoscale. Here, we characterize the intensity and phase-resolved plasmonic response of isolated nanopatch antennas by cathodoluminescence microscopy. Furthermore, we explore the distinction between optical and electron beam spectroscopies of …


Hybrid Scenario Generation Method For Stochastic Virtual Bidding In Electricity Market, Dongliang Xiao,, Wei Qiao Sep 2021

Hybrid Scenario Generation Method For Stochastic Virtual Bidding In Electricity Market, Dongliang Xiao,, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

Stochastic optimization can be used to generate optimal bidding strategies for virtual bidders in which the uncertain electricity prices are represented by using scenarios. This paper proposes a hybrid scenario generation method for electricity price using a seasonal autoregressive integrated moving average (SARIMA) model and historical data. The electricity price spikes are first identified by using an outlier detection method. Then, the historical data are decomposed into base and spike components. Next, the base and spike component scenarios are generated by using the SARIMA- and historical data-based methods, respectively. Finally, the electricity price scenarios are obtained by combining the base …


Unconventional Van Der Waals Heterostructures Beyond Stacking, Peter Sutter, Eli A. Sutter Sep 2021

Unconventional Van Der Waals Heterostructures Beyond Stacking, Peter Sutter, Eli A. Sutter

Department of Electrical and Computer Engineering: Faculty Publications

Two-dimensional crystals provide exceptional opportunities for integrating dissimilar materials and forming interfaces where distinct properties and phenomena emerge. To date, research has focused on two basic heterostructure types: vertical van der Waals stacks and laterally joined monolayer crystals with in-plane line interfaces. Much more diverse architectures and interface configurations can be realized in the few-layer and multilayer regime, and if mechanical stacking and single-layer growth are replaced by processes taking advantage of self-organization, conversions between polymorphs, phase separation, strain effects, and shaping into the third dimension. Here, we highlight such opportunities for engineering heterostructures, focusing on group IV chalcogenides, a …


High-Frequency And Below Bandgap Anisotropic Dielectric Constants In Α-(AlXGa1-X)2O3 (0≤X≤1), Matthew Hilfiker, Ufuk Kilic, Megan Stokey, Riena Jinno, Yongjin Cho, Huili Grace Xing, Debdeep Jena, Rafal Korlacki, Mathias Schubert Sep 2021

High-Frequency And Below Bandgap Anisotropic Dielectric Constants In Α-(AlXGa1-X)2O3 (0≤X≤1), Matthew Hilfiker, Ufuk Kilic, Megan Stokey, Riena Jinno, Yongjin Cho, Huili Grace Xing, Debdeep Jena, Rafal Korlacki, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

A Mueller matrix spectroscopic ellipsometry approach was used to investigate the anisotropic dielectric constants of corundum α-(AlxGa1-x)2O3 thin films in their below bandgap spectral regions. The sample set was epitaxially grown using plasma-assisted molecular beam epitaxy on m-plane sapphire. The spectroscopic ellipsometry measurements were performed at multiple azimuthal angles to resolve the uniaxial dielectric properties. A Cauchy dispersion model was applied, and high-frequency dielectric constants are determined for polarization perpendicular (ε∞,⟂) and parallel (ε∞,∥) to the thin film c-axis. The optical birefringence is negative throughout the …


An Efficient Multi-Message And Multi-Receiver Signcryption Scheme For Heterogeneous Smart Mobile Iot, Jianying Qiu, Kai Fan, Kuan Zhang, Qiang Pan, Hui Li, Yintang Yang Jul 2021

An Efficient Multi-Message And Multi-Receiver Signcryption Scheme For Heterogeneous Smart Mobile Iot, Jianying Qiu, Kai Fan, Kuan Zhang, Qiang Pan, Hui Li, Yintang Yang

Department of Electrical and Computer Engineering: Faculty Publications

The Internet of Things (IoT) is developing towards smart and mobile Internet of Things (SM-IoT), which has made great progress. Due to the inherent heterogeneity, distribution, intensive communication, and resource constraints of SM-IoT, efficient security and privacy communication protocols become a particularly critical challenge. Signcryption has received considerable attention. Various signcryption schemes have been proposed to solve secure communication. However, most of them are low in efficiency, without the consideration of characteristics of the SM-IoT. In this paper, we propose a signcryption scheme to achieve efficient secure multi-message and multi-receiver communication for the heterogeneous and distributed SM-IoT. We develop Identity-based …


Optical Phonon Modes, Static And High-Frequency Dielectric Constants, And Effective Electron Mass Parameter In Cubic In2O3, Megan Stokey, Rafal Korlacki, Sean Knight, Alexander Ruder, Matthew J. Hilfiker, Zbigniew Galazka, Klaus Irmscher, Yuxuan Zhang, Hongping Zhao, Vanya Darakchieva, Mathias Schubert Jun 2021

Optical Phonon Modes, Static And High-Frequency Dielectric Constants, And Effective Electron Mass Parameter In Cubic In2O3, Megan Stokey, Rafal Korlacki, Sean Knight, Alexander Ruder, Matthew J. Hilfiker, Zbigniew Galazka, Klaus Irmscher, Yuxuan Zhang, Hongping Zhao, Vanya Darakchieva, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

A complete set of all optical phonon modes predicted by symmetry for bixbyite structure indium oxide is reported here from a combination of far-infrared and infrared spectroscopic ellipsometry, as well as first principles calculations. Dielectric function spectra measured on high quality, marginally electrically conductive melt grown single bulk crystals are obtained on a wavelength-by-wavelength (also known as point-by-point) basis and by numerical reduction of a subtle free charge carrier Drude model contribution. A four-parameter semi-quantum model is applied to determine all 16 pairs of infrared-active transverse and longitudinal optical phonon modes, including the high-frequency dielectric constant, ε=4.05±0.05. The …


Spontaneous Formation Of Multilayer Refractory Carbide Coatings In A Molten Salt Media, Loic Constantin, Lisha Fan, Mathilde Pouey, Jérôme Roger, Bai Cui, Jean-François Silvain, Yongfeng Lu Apr 2021

Spontaneous Formation Of Multilayer Refractory Carbide Coatings In A Molten Salt Media, Loic Constantin, Lisha Fan, Mathilde Pouey, Jérôme Roger, Bai Cui, Jean-François Silvain, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Refractory materials hold great promise to develop functional multilayer coating for extreme environments and temperature applications but require high temperature and complex synthesis to overcome their strong atomic bonding and form a multilayer structure. Here, a spontaneous reaction producing sophisticated multilayer refractory carbide coatings on carbon fiber (CF) is reported. This approach utilizes a relatively low-temperature (950 °C) moltensalt process for forming refractory carbides. The reaction of titanium (Ti), chromium (Cr), and CF yields a complex, high-quality multilayer carbide coating composed of 1) Cr carbide (Cr3C2), 2) Ti carbide, and 3) Cr3C2 layers. …


Visible-To-Thermal Transfer Learning For Facial Landmark Detection, Domenick D. Poster, Shuowen Hu, Nathan J. Short, Benjamin S. Riggan, Nasser M. Nasrabadi Apr 2021

Visible-To-Thermal Transfer Learning For Facial Landmark Detection, Domenick D. Poster, Shuowen Hu, Nathan J. Short, Benjamin S. Riggan, Nasser M. Nasrabadi

Department of Electrical and Computer Engineering: Faculty Publications

There has been increasing interest in face recognition in the thermal infrared spectrum. A critical step in this process is face landmark detection. However, landmark detection in the thermal spectrum presents a unique set of challenges compared to in the visible spectrum: inherently lower spatial resolution due to longer wavelength, differences in phenomenology, and limited availability of labeled thermal face imagery for algorithm development and training. Thermal infrared imaging does have the advantage of being able to passively acquire facial heat signatures without the need for active or ambient illumination in low light and nighttime environments. In such scenarios, thermal …


Recent Advances In Terahertz Photonic Technologies Based On Graphene And Their Applications, Tianjing Guo, Christos Argyropoulos Mar 2021

Recent Advances In Terahertz Photonic Technologies Based On Graphene And Their Applications, Tianjing Guo, Christos Argyropoulos

Department of Electrical and Computer Engineering: Faculty Publications

Graphene is a unique 2D material that has been extensively investigated due to its extraordinary photonic, electronic, thermal, and mechanical properties. Excited plasmons along its surface and other unique features are expected to play an important role in many emerging photonic technologies with drastically improved and tunable functionalities. This review is focused on presenting several recently introduced photonic phenomena based on graphene, beyond its usual linear response, such as nonlinear, active, topological, and nonreciprocal effects. The physical mechanisms and various envisioned photonic applications corresponding to these novel intriguing functionalities are also reported. The presented graphene-based technologies promise to revolutionize the …


Kegg2net: Deducing Gene Interaction Networks And Acyclic Graphs From Kegg Pathways, Sree K. Chanumolu, Mustafa Albahrani, Handan Can, Hasan H. Otu Mar 2021

Kegg2net: Deducing Gene Interaction Networks And Acyclic Graphs From Kegg Pathways, Sree K. Chanumolu, Mustafa Albahrani, Handan Can, Hasan H. Otu

Department of Electrical and Computer Engineering: Faculty Publications

The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database provides a manual curation of biological pathways that involve genes (or gene products), metabolites, chemical compounds, maps, and other entries. However, most applications and datasets involved in omics are gene or protein-centric requiring pathway representations that include direct and indirect interactions only between genes. Furthermore, special methodologies, such as Bayesian networks, require acyclic representations of graphs. We developed KEGG2Net, a web resource that generates a network involving only the genes represented on a KEGG pathway with all of the direct and indirect gene-gene interactions deduced from the pathway. KEGG2Net offers …


Zinc Gallate Spinel Dielectric Function, Band-To-Band Transitions, And Γ-Point Effective Mass Parameters, Matthew J. Hilfiker, Megan Stokey, Rafal Korlacki, Ufuk Kilic, Zbigniew Galazka, Klaus Irmscher, Stefan Zollner, Mathias Schubert Mar 2021

Zinc Gallate Spinel Dielectric Function, Band-To-Band Transitions, And Γ-Point Effective Mass Parameters, Matthew J. Hilfiker, Megan Stokey, Rafal Korlacki, Ufuk Kilic, Zbigniew Galazka, Klaus Irmscher, Stefan Zollner, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

We determine the dielectric function of the emerging ultrawide bandgap semiconductor ZnGa2O4 from the near-infrared (0.75 eV) into the vacuum ultraviolet (8.5 eV) spectral regions using spectroscopic ellipsometry on high quality single crystal substrates. We perform density functional theory calculations and discuss the band structure and the Brillouin zone Γ-point band-to-band transition energies, their transition matrix elements, and effective band mass parameters. We find an isotropic effective mass parameter (0.24me) at the bottom of the Γ-point conduction band, which equals the lowest valence band effective mass parameter at the top of the highly anisotropic …


Plasmonic Waveguides To Enhance Quantum Electrodynamic Phenomena At The Nanoscale, Ying Li, Christos Argyropoulos Feb 2021

Plasmonic Waveguides To Enhance Quantum Electrodynamic Phenomena At The Nanoscale, Ying Li, Christos Argyropoulos

Department of Electrical and Computer Engineering: Faculty Publications

The emerging field of plasmonics can lead to enhanced light-matter interactions at extremely nanoscale regions. Plasmonic (metallic) devices promise to efficiently control both classical and quantum properties of light. Plasmonic waveguides are usually used to excite confined electromagnetic modes at the nanoscale that can strongly interact with matter. The analysis of these nanowaveguides exhibits similarities with their low frequency microwave counterparts. In this article, we review ways to study plasmonic nanostructures coupled to quantum optical emitters from a classical electromagnetic perspective. These quantum emitters are mainly used to generate single-photon quantum light that can be employed as a quantum bit …


Anisotropic Dielectric Functions, Band-To-Band Transitions, And Critical Points In Α-Ga2O3, Matthew J. Hilfiker, Rafal Korlacki, Riena Jinno, Yongjin Cho, Huili Grace Xing, Debdeep Jena, Ufuk Kilic, Megan Stokey, Mathias Schubert Feb 2021

Anisotropic Dielectric Functions, Band-To-Band Transitions, And Critical Points In Α-Ga2O3, Matthew J. Hilfiker, Rafal Korlacki, Riena Jinno, Yongjin Cho, Huili Grace Xing, Debdeep Jena, Ufuk Kilic, Megan Stokey, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

We use a combined generalized spectroscopic ellipsometry and density functional theory approach to determine and analyze the anisotropic dielectric functions of an α-Ga2O3 thin film. The sample is grown epitaxially by plasma-assisted molecular beam epitaxy on m-plane sapphire. Generalized spectroscopic ellipsometry data from multiple sample azimuths in the spectral range from 0.73 eV to 8.75 eV are simultaneously analyzed. Density functional theory is used to calculate the valence and conduction band structure. We identify, for the indirect-bandgap material, two direct band-to-band transitions with M0-type van Hove singularities for polarization perpendicular to the c axis, …


Laser Vibrational Excitation Of Radicals To Prevent Crystallinity Degradation Caused By Boron Doping In Diamond, L Fan, L Constantin, Z P. Wu, K A. Mcelveen, X G. Chen, F Wang, C Debiemme-Chouvy, B Cui, R Y. Lai, X Li, J F. Silvain, Y F. Lu Jan 2021

Laser Vibrational Excitation Of Radicals To Prevent Crystallinity Degradation Caused By Boron Doping In Diamond, L Fan, L Constantin, Z P. Wu, K A. Mcelveen, X G. Chen, F Wang, C Debiemme-Chouvy, B Cui, R Y. Lai, X Li, J F. Silvain, Y F. Lu

Department of Electrical and Computer Engineering: Faculty Publications

Pursuing high-level doping without deteriorating crystallinity is prohibitively difficult but scientifically crucial to unleashing the hidden power of materials. This study demonstrates an effective route for maintaining lattice integrity during the combustion chemical vapor deposition of highly conductive boron-doped diamonds (BDDs) through laser vibrational excitation of a growth-critical radical, boron dihydride (BH2). The improved diamond crystallinity is attributed to a laser-enabled, thermal nonequilibrium suppression of the relative abundance of boron hydrides (BH), whose excessive presence induces boron segregation and disturbs the crystallization. The BDDs show a boron concentration of 4.3 × 1021 cm−3, a film …


Targeted Metabolomics Analysis Of Postoperative Delirium, Bridget A. Tripp, Simon T. Dillon, Min Yuan, John M. Asara, Sarinnapha M. Vasunilashorn, Tamara G. Fong, Eran D. Metzger, Sharon K. Inouye, Zhongcong Xie, Long H. Ngo, Edward R. Marcantonio, Towia A. Libermann, Hasan H. Otu Jan 2021

Targeted Metabolomics Analysis Of Postoperative Delirium, Bridget A. Tripp, Simon T. Dillon, Min Yuan, John M. Asara, Sarinnapha M. Vasunilashorn, Tamara G. Fong, Eran D. Metzger, Sharon K. Inouye, Zhongcong Xie, Long H. Ngo, Edward R. Marcantonio, Towia A. Libermann, Hasan H. Otu

Department of Electrical and Computer Engineering: Faculty Publications

Postoperative delirium is the most common complication among older adults undergoing major surgery. The pathophysiology of delirium is poorly understood, and no blood-based, predictive markers are available. We characterized the plasma metabolome of 52 delirium cases and 52 matched controls from the Successful Aging after Elective Surgery (SAGES) cohort (N= 560) of patients ≥ 70 years old without dementia undergoing scheduled major non-cardiac surgery. We applied targeted mass spectrometry with internal standards and pooled controls using a nested matched case-control study preoperatively (PREOP) and on postoperative day 2 (POD2) to identify potential delirium risk and disease markers. Univariate analyses identifed …


Photovoltaic Panels Tilt Angle Optimization, Kerry A. Sado, Lokman H. Hassan, Shivan Sado Jan 2021

Photovoltaic Panels Tilt Angle Optimization, Kerry A. Sado, Lokman H. Hassan, Shivan Sado

Department of Electrical and Computer Engineering: Faculty Publications

The tilt angle of solar panels is significant for capturing solar radiation that reaches the surface of the panel. Photovoltaic (PV) performance and efficiency are highly affected by its angle of tilt with respect to the horizontal plane. The amount of radiation reaching the surface of a PV panel changes with the changes in its tilt angle, hence adding a solar tracking system will maximize the amount of solar radiation reaching the surface of a PV panel at any time during the day, however, integrating solar tracking system will increase the total cost and maintenance of any PV system. Thus, …


Near-Unity Broadband Omnidirectional Emissivity Via Femtosecond Laser Surface Processing, Andrew Reicks, Alfred Tsubaki, Mark Anderson, Jace Wieseler, Larousse Khosravi Khorashad, Jeffrey E. Shield, George Gogos, Dennis Alexander, Christos Argyropoulos, Craig Zuhlke Jan 2021

Near-Unity Broadband Omnidirectional Emissivity Via Femtosecond Laser Surface Processing, Andrew Reicks, Alfred Tsubaki, Mark Anderson, Jace Wieseler, Larousse Khosravi Khorashad, Jeffrey E. Shield, George Gogos, Dennis Alexander, Christos Argyropoulos, Craig Zuhlke

Department of Electrical and Computer Engineering: Faculty Publications

It is very challenging to achieve near perfect absorption or emission that is both broadband and omnidirectional while utilizing a scalable fabrication process. Femtosecond laser surface processing is an emerging low-cost and large-scale manufacturing technique used to directly and permanently modify the surface properties of a material. The versatility of this technique to produce tailored surface properties has resulted in a rapidly growing number of applications. Here, we demonstrate near perfect, broadband, omnidirectional emissivity from aluminum surfaces by tuning the laser surface processing parameters including fluence, pulse count, and the ambient gas. Full-wave simulations and experimental results prove that the …


End-Effector Contact And Force Detection For Miniature Autonomous Robots Performing Lunar And Expeditionary Surgery, Eric T. Psota, Jay Carlson, Priscila Rodrigues Armijo, Laura Flores, Ka-Chun Siu, Dmitry Oleynikov, Shane Farritor, Nathan Bills Jan 2021

End-Effector Contact And Force Detection For Miniature Autonomous Robots Performing Lunar And Expeditionary Surgery, Eric T. Psota, Jay Carlson, Priscila Rodrigues Armijo, Laura Flores, Ka-Chun Siu, Dmitry Oleynikov, Shane Farritor, Nathan Bills

Department of Electrical and Computer Engineering: Faculty Publications

Introduction: The U.S. Space Force was stood up on December 20, 2019 as an independent branch under the Air Force consisting of about 16,000 active duty and civilian personnel focused singularly on space. In addition to the Space Force, the plans by NASA and private industry for exploration-class long-duration missions to the moon, near-earth asteroids, and Mars makes semi-independent medical capability in space a priority. Current practice for space-based medicine is limited and relies on a “life-raft” scenario for emergencies. Discussions by working groups on military space-based medicine include placing a Role III equivalent facility in a lunar surface station. …


The Anisotropic Quasi-Static Permittivity Of Single-Crystal Β-Ga2O3 Measured By Terahertz Spectroscopy, Prashanth Gopalan, Sean Knight, Ashish Chanana, Megan Stokey, Praneeth Ranga, Michael A. Scarpulia, Sriram Krishnamoorthy, Vanya Darakchieva, Zbigniew Galazka, Klaus Irmscher, Andreas Fiedler, Steve Blair, Mathias Schubert, Berardi Sensale-Rodriguez Jan 2021

The Anisotropic Quasi-Static Permittivity Of Single-Crystal Β-Ga2O3 Measured By Terahertz Spectroscopy, Prashanth Gopalan, Sean Knight, Ashish Chanana, Megan Stokey, Praneeth Ranga, Michael A. Scarpulia, Sriram Krishnamoorthy, Vanya Darakchieva, Zbigniew Galazka, Klaus Irmscher, Andreas Fiedler, Steve Blair, Mathias Schubert, Berardi Sensale-Rodriguez

Department of Electrical and Computer Engineering: Faculty Publications

The quasi-static anisotropic permittivity parameters of electrically insulating beta gallium oxide (β-Ga2O3) were determined by terahertz spectroscopy. Polarization-resolved frequency domain spectroscopy in the spectral range from 200 GHz to 1 THz was carried out on bulk crystals along different orientations. Principal directions for permittivity were determined along crystallographic axes c and b and reciprocal lattice direction a*. No significant frequency dispersion in the real part of dielectric permittivity was observed in the measured spectral range. Our results are in excellent agreement with recent radio frequency capacitance measurements as well as with extrapolations from recent infrared measurements …


Recent Advances In Terahertz Photonic Technologies Based On Graphene And Their Applications, Tianjing Guo, Christos Argyropoulos Jan 2021

Recent Advances In Terahertz Photonic Technologies Based On Graphene And Their Applications, Tianjing Guo, Christos Argyropoulos

Department of Electrical and Computer Engineering: Faculty Publications

Graphene is a unique 2D material that has been extensively investigated due to its extraordinary photonic, electronic, thermal, and mechanical properties. Excited plasmons along its surface and other unique features are expected to play an important role in many emerging photonic technologies with drastically improved and tunable functionalities. This review is focused on presenting several recently introduced photonic phenomena based on graphene, beyond its usual linear response, such as nonlinear, active, topological, and nonreciprocal effects. The physical mechanisms and various envisioned photonic applications corresponding to these novel intriguing functionalities are also reported. The presented graphene-based technologies promise to revolutionize the …


A Routine Electroencephalography Monitoring System For Automated Sports-Related Concussion Detection, Amirsalar Mansouri, Patrick Ledwidge, Khalid Sayood, Dennis L. Molfese Jan 2021

A Routine Electroencephalography Monitoring System For Automated Sports-Related Concussion Detection, Amirsalar Mansouri, Patrick Ledwidge, Khalid Sayood, Dennis L. Molfese

Department of Electrical and Computer Engineering: Faculty Publications

Cases of concussions in the United States keep increasing and are now up to 2 million to 3 million incidents per year. Although concussions are recoverable and usually not life-threatening, the degree and rate of recovery may vary depending on age, severity of the injury, and past concussion history. A subsequent concussion before full recovery may lead to more-severe brain damage and poorer outcomes. Electroencephalography (EEG) recordings can identify brain dysfunctionality and abnormalities, such as after a concussion. Routine EEG monitoring can be a convenient method for reducing unreported injuries and preventing long-term damage, especially among groups with a greater …