Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 11041 - 11070 of 302419

Full-Text Articles in Physical Sciences and Mathematics

Due Tomorrow, Do Tomorrow: Measuring And Reducing Procrastination Behavior Among Introductory Physics Students In An Online Environment, Zachary Felker Aug 2023

Due Tomorrow, Do Tomorrow: Measuring And Reducing Procrastination Behavior Among Introductory Physics Students In An Online Environment, Zachary Felker

Electronic Theses and Dissertations, 2020-2023

This work is focused on the measurement and prevention of procrastination behavior among college level introductory physics students completing online assignments in the form of mastery-based online learning modules. The research is conducted in two studies. The first study evaluates the effectiveness of offering students the opportunity to earn a small amount of extra credit for completing portions of their homework early. Unsupervised machine learning is used to identify an optimum cutoff duration which differentiates taking a short break during a continuous study session from a long break between two different study sessions. Using this cutoff, the study shows that …

Go to article

Studying Memes During Covid Lockdown As A Lens Through Which To Understand Video-Mediated Communication Interactions, Tatyana Claytor Aug 2023

Studying Memes During Covid Lockdown As A Lens Through Which To Understand Video-Mediated Communication Interactions, Tatyana Claytor

Electronic Theses and Dissertations, 2020-2023

The purpose of this study is to analyze image macros about video-mediated communication (VMC) created during the time frame of 2020-2021 when people all over the world started using Zoom and VMC for work and school. It is a unique opportunity to study how users' interactions with themselves and with others were affected at a time when a lot of people started using the technology at the same time. Because the focus is on interactions, I narrowed it down to three topics to analyze the memes: presence, self, and space and place to analyze the memes. I chose memes relating …

Go to article

Human Recognition Theory And Facial Recognition Technology: A Topic Modeling Approach To Understanding The Ethical Implication Of A Developing Algorithmic Technologies Landscape On How We View Ourselves And Are Viewed By Others, Hajer Albalawi Aug 2023

Human Recognition Theory And Facial Recognition Technology: A Topic Modeling Approach To Understanding The Ethical Implication Of A Developing Algorithmic Technologies Landscape On How We View Ourselves And Are Viewed By Others, Hajer Albalawi

Electronic Theses and Dissertations, 2020-2023

The emergence of algorithmic-driven technology has significantly impacted human life in the current century. Algorithms, as versatile constructs, hold different meanings across various disciplines, including computer science, mathematics, social science, and human-artificial intelligence studies. This study defines algorithms from an ethical perspective as the foundation of an information society and focuses on their implications in the context of human recognition. Facial recognition technology, driven by algorithms, has gained widespread use, raising important ethical questions regarding privacy, bias, and accuracy. This dissertation aims to explore the impact of algorithms on machine perception of human individuals and how humans perceive one another …

Go to article

Theoretical Analysis Of Charge Conduction And Rectification In Self-Assembled-Monolayers In Molecular Junctions, Francis Adoah Aug 2023

Theoretical Analysis Of Charge Conduction And Rectification In Self-Assembled-Monolayers In Molecular Junctions, Francis Adoah

Electronic Theses and Dissertations, 2020-2023

As electrical devices shrink to the atomic scale, it is expected that Moore's law will soon be obsolete for semiconductor devices. In 1974, Avriam and Ratner predicted that organic devices could replace semiconductor technology, leading to extensive research on molecular-based organic devices. This dissertation delves into the theoretical frameworks used to examine the transport in molecular junctions and aims to enhance our comprehension of charge transport and conduction properties. The studies presented in this thesis illustrates that a molecule's alteration by just a single atom can change it from an insulator to a conductor, and also that, by fine-tuning the …

Go to article

Ocr Post-Processing Using Large Language Models, Mahdi Hajiali Aug 2023

Ocr Post-Processing Using Large Language Models, Mahdi Hajiali

UNLV Theses, Dissertations, Professional Papers, and Capstones

Optical Character Recognition (OCR) technology transforms textual visuals into an electronically readable, non-graphical format of the text. This allows the editing and other text manipulation of the content by language technology software such as machine translation, text comprehension, query-answering systems, and search engines. While Optical Character Recognition (OCR) systems continually progress towards greater precision, several complications persist when dealing with low-resolution source images or those with multicolored backgrounds. Consequently, the text derived from OCR necessitates additional refinement to optimize accuracy, beneficial for various subsequent applications. It is recognized that the character accuracy of OCR-generated text may influence certain natural language …

Go to article

Approved Butte Reduction Works (Brw) Smelter Area Mine Waste Remediation And Contaminated Groundwater Hydraulic Control Site Quality Assurance Project Plan (Qapp) For Microbial Analysis And Biotreatability; Request For Change Brw-2023-02, Josh Bryson Aug 2023

Approved Butte Reduction Works (Brw) Smelter Area Mine Waste Remediation And Contaminated Groundwater Hydraulic Control Site Quality Assurance Project Plan (Qapp) For Microbial Analysis And Biotreatability; Request For Change Brw-2023-02, Josh Bryson

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.

Go to article

Draft Final 2023 Butte Priority Soils Operable Unit Helehan Borrow Submittal #1, Pioneer Technical Services, Inc. Aug 2023

Draft Final 2023 Butte Priority Soils Operable Unit Helehan Borrow Submittal #1, Pioneer Technical Services, Inc.

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.

Go to article

Florida's Vanishing Heritage: Climate Risk And Adaptation At Florida Heritage Sites, Levi Watson Aug 2023

Florida's Vanishing Heritage: Climate Risk And Adaptation At Florida Heritage Sites, Levi Watson

Electronic Theses and Dissertations, 2020-2023

This thesis examines history and preservation at coastal cultural heritage sites threatened by climate change and explores climate adaptation strategies at two sites on Florida's Atlantic coast. Current climate change models indicate the planet may see as much as 1.1 meters, or four feet, of global average sea level rise by the year 2100, requiring site managers to intervene by using adaptation techniques to improve resilience and guard against the loss of cultural heritage monuments. Understanding the history and importance of these sites to the surrounding communities and their numerous stakeholders is the first step to ensuring these sites remain …

Go to article

Theoretical Framework Of Exchange Coupled Tripartite Spin Systems With Magnetic Anisotropy And Predictions Of Spin And Electronic Transport Properties For Their Use In Quantum Architectures, Eric Switzer Aug 2023

Theoretical Framework Of Exchange Coupled Tripartite Spin Systems With Magnetic Anisotropy And Predictions Of Spin And Electronic Transport Properties For Their Use In Quantum Architectures, Eric Switzer

Electronic Theses and Dissertations, 2020-2023

There has been significant interest in spin systems involving two or more coupled spins as a single logical qubit, particularly for scalable quantum computing architectures. Recent realizations include the so-called singlet-triplet qubits and coupled magnetic molecules. An important class of coupled-spin systems, the three-spin paradigm for spin greater than 1/2, has not yet been fully realized in scalable qubit architectures. In this thesis, I develop the theoretical framework to investigate a class of tripartite spin models for realistic systems. First, I model a spin 1/2 particle (e.g., an electron) and two spin 1 particles (in a dimer arrangement) coupled with …

Go to article

A Study On Robustness And Semantic Understanding Of Visual Models, Madeline Chantry Aug 2023

A Study On Robustness And Semantic Understanding Of Visual Models, Madeline Chantry

Electronic Theses and Dissertations, 2020-2023

Vision models have improved in popularity and performance on many tasks since the emergence of large-scale datasets, improved access to computational resources, and new model architectures like the transformer. However, it is still not well understood if these models can be deployed in the real world. Because these models are "blackbox" architectures, we do not fully understand what these models are truly learning. An understanding of what models learn "underneath the hood" would result in better improvements for real-world scenarios. Motivated by this, we benchmark these impressive visual models using newly proposed datasets and tasks on their robustness and their …

Go to article

Drivers Of Variability In Blue Carbon Stocks And Burial Rates Across European Estuarine Habitats, Inés Mazarrasa, Joao M. Neto, Tjeerd J. Bouma, Tim Grandjean, Jordi Garcia-Orellana, Pere Masqué, María Recio, Óscar Serrano, Araceli Puente, José A. Juanes Aug 2023

Drivers Of Variability In Blue Carbon Stocks And Burial Rates Across European Estuarine Habitats, Inés Mazarrasa, Joao M. Neto, Tjeerd J. Bouma, Tim Grandjean, Jordi Garcia-Orellana, Pere Masqué, María Recio, Óscar Serrano, Araceli Puente, José A. Juanes

Research outputs 2022 to 2026

The implementation of climate change mitigation strategies based on the conservation and restoration of Blue Carbon ecosystems requires a deep understanding of the magnitude and variability in organic carbon (Corg) storage across and within these ecosystems. This study explored the variability in soil Corg stocks and burial rates across and within intertidal estuarine habitats of the Atlantic European coast and its relation to biotic and abiotic drivers. A total of 136 soil cores were collected across saltmarshes located at different tidal zones (high marsh, N = 45; low marsh, N = 30), seagrass meadows (N = 17) and tidal flats …

Go to article

A Neural-Network-Based Landscape Search Engine: Lse Wisconsin, Matthew Haffner, Matthew Dewitte, Papia F. Rozario, Gustavo A. Ovando-Montejo Aug 2023

A Neural-Network-Based Landscape Search Engine: Lse Wisconsin, Matthew Haffner, Matthew Dewitte, Papia F. Rozario, Gustavo A. Ovando-Montejo

Environment and Society Faculty Publications

The task of image retrieval is common in the world of data science and deep learning, but it has received less attention in the field of remote sensing. The authors seek to fill this gap in research through the presentation of a web-based landscape search engine for the US state of Wisconsin. The application allows users to select a location on the map and to find similar locations based on terrain and vegetation characteristics. It utilizes three neural network models—VGG16, ResNet-50, and NasNet—on digital elevation model data, and uses the NDVI mean and standard deviation for comparing vegetation data. The …

Go to article

Improved Endmember Mixing Analysis (Emma): Application To A Nested Catchment, Provo River, Northern Utah, Alyssa Nicole Thompson Aug 2023

Improved Endmember Mixing Analysis (Emma): Application To A Nested Catchment, Provo River, Northern Utah, Alyssa Nicole Thompson

Theses and Dissertations

An endmember mixing analysis (EMMA) is a hydrograph separation technique used to identify and quantify stream source contributions, but the error within the results of the analysis itself can be difficult to quantify. Employing EMMA to accurately quantify these contributions is particularly important for critical watersheds that supply water to large populations, such as montane watersheds. We applied EMMA to the Provo River, a nested catchment with three monitoring locations in northern Utah, to understand the limitations and potential improvements that could be made to EMMA. Four main endmembers (quartzite groundwater, soil water, snow and carbonate groundwater) were identified for …

Go to article

A Multi-Layer Information Dissemination Model And Interference Optimization Strategy For Communication Networks In Disaster Areas, Yuexia Zhang, Yang Hong, Mohsen Guizani, Sheng Wu, Peiying Zhang, Ruiqi Liu Aug 2023

A Multi-Layer Information Dissemination Model And Interference Optimization Strategy For Communication Networks In Disaster Areas, Yuexia Zhang, Yang Hong, Mohsen Guizani, Sheng Wu, Peiying Zhang, Ruiqi Liu

Machine Learning Faculty Publications

The communication network in disaster areas (CNDA) can disseminate the key disaster information in time and provide basic information support for decision-making and rescuing. Therefore, it is of great significance to study the information dissemination mechanism of CNDA. However, a CNDA is vulnerable to interference, which affects information dissemination and rescuing. To solve this problem, this paper established a multi-layer information dissemination model of CNDA (MMND) which models the CNDA from the perspective of degree distribution of nodes. The information dissemination process and equilibrium state in CNDA is analyzed by an improved dynamic dissemination method. Then, the effects of the …

Go to article

Autonomous Shipwreck Detection & Mapping, William Ard Aug 2023

Autonomous Shipwreck Detection & Mapping, William Ard

LSU Master's Theses

This thesis presents the development and testing of Bruce, a low-cost hybrid Remote Operated Vehicle (ROV) / Autonomous Underwater Vehicle (AUV) system for the optical survey of marine archaeological sites, as well as a novel sonar image augmentation strategy for semantic segmentation of shipwrecks. This approach takes side-scan sonar and bathymetry data collected using an EdgeTech 2205 AUV sensor integrated with an Harris Iver3, and generates augmented image data to be used for the semantic segmentation of shipwrecks. It is shown that, due to the feature enhancement capabilities of the proposed shipwreck detection strategy, correctly identified areas have a 15% …

Go to article

Efficient And Secure Digital Signature Algorithm (Dsa), Nissa Mehibel, M'Hamed Hamadouche Aug 2023

Efficient And Secure Digital Signature Algorithm (Dsa), Nissa Mehibel, M'Hamed Hamadouche

Emirates Journal for Engineering Research

The digital signature is used to ensure the integrity of messages as well as the authentication and non-repudiation of users. Today it has a very important role in information security. Digital signature is used in various fields such as e-commerce and e-voting, health, internet of things (IOT). Many digital signature schemes have been proposed, depending on the computational cost and security level. In this paper, we analyzed a recently proposed digital signature scheme based on the discrete logarithm problem (DLP). Our analysis shows that the scheme is not secure against the repeated random number attack to determine the secret keys …

Go to article

Semantically Structured Creative Computer Systems & Automated Evaluation Of Creative Artifacts, Brad Spendlove Aug 2023

Semantically Structured Creative Computer Systems & Automated Evaluation Of Creative Artifacts, Brad Spendlove

Theses and Dissertations

Computational creativity seeks, in part, to develop autonomous agents that exhibit creativity. Language is an ideal creative domain for studying computer agents due to its rich interconnectedness and immense space of possible combinations. This dissertation explores the design, testing, and theory of creative computer systems that write microfiction and play the board game Codenames. The designs of these systems are all similarly based on building up creative artifacts from the underlying structure of the relationships between words. A critical component of the creative process is the ability to evaluate the quality of creative output. Human and automated assessment of our …

Go to article

Self-Supervised Pretraining And Transfer Learning On Fmri Data With Transformers, Sean Paulsen Aug 2023

Self-Supervised Pretraining And Transfer Learning On Fmri Data With Transformers, Sean Paulsen

Dartmouth College Ph.D Dissertations

Transfer learning is a machine learning technique founded on the idea that knowledge acquired by a model during “pretraining” on a source task can be transferred to the learning of a target task. Successful transfer learning can result in improved performance, faster convergence, and reduced demand for data. This technique is particularly desirable for the task of brain decoding in the domain of functional magnetic resonance imaging (fMRI), wherein even the most modern machine learning methods can struggle to decode labelled features of brain images. This challenge is due to the highly complex underlying signal, physical and neurological differences between …

Go to article

Self-Immolative Hydrogels With Stimulus-Mediated On-Off Degradation., Jue Gong, Aneta Borecki, Elizabeth R Gillies Aug 2023

Self-Immolative Hydrogels With Stimulus-Mediated On-Off Degradation., Jue Gong, Aneta Borecki, Elizabeth R Gillies

Chemistry Publications

Hydrogels are of interest for a wide range of applications from sensors to drug delivery and tissue engineering. Self-immolative polymers, which depolymerize from end-to-end following a single backbone or end-cap cleavage, offer advantages such as amplification of the stimulus-mediated cleavage event through a cascade degradation process. It is also possible to change the active stimulus by changing only a single end-cap or linker unit. However, there are very few examples of self-immolative polymer hydrogels, and the reported examples exhibited relatively poor stability in their nontriggered state or slow degradation after triggering. Described here is the preparation of hydrogels composed of …

Go to article

The Student Becomes The Teacher: Training High-Performance Language Models More Sample-Efficiently From Small Models Via Superstilling, Chaz Allen Gundry Aug 2023

The Student Becomes The Teacher: Training High-Performance Language Models More Sample-Efficiently From Small Models Via Superstilling, Chaz Allen Gundry

Theses and Dissertations

Recent advances including the Transformer architecture have revolutionized the Natural Language Processing community by providing immense performance improvements across many tasks, including the development of Large Language Models (LLMs). LLMs show enormous promise as few-shot learners, common-sense knowledge repositories, conversational agents, writing assistants, and coding tools, and are gaining widespread traction in commercial industry. However, LLMs are expensive and time-consuming to train, requiring many passes over terabytes of data for the largest models. In this paper, we present Superstilling, a method for reducing the sample complexity of language model training by distilling the knowledge from a previously-trained model (the teacher) …

Go to article

Multi-Color Fluorescent Microscopy And Deep Learning For Studying Eukaryotic Organelles: Unveiling Cellular Growth In A System Biology Perspective, Shixing Wang Aug 2023

Multi-Color Fluorescent Microscopy And Deep Learning For Studying Eukaryotic Organelles: Unveiling Cellular Growth In A System Biology Perspective, Shixing Wang

Arts & Sciences Electronic Theses and Dissertations

Eukaryotic cells are building blocks to complex living systems, characterized by membrane-bound organelles. Studying how eukaryotic organelles react to cellular growth and size increase is crucial, but it demands biochemical and biophysical manipulations, as well as quantitative observation tools in microscopy. We developed a multi-color yeast strain with tagged fluorescent proteins, enabling systematic measurements of 6 organelles inside each cell using spectral confocal microscopy. These measurements provided insights into how organelle biogenesis is coordinated with cellular size and growth rate regulation via different signaling pathways. To explore cellular growth under dynamic conditions, I utilized deep learning for organelle recognition using …

Go to article

Improving Xrd Analysis With Machine Learning, Rachel E. Drapeau Aug 2023

Improving Xrd Analysis With Machine Learning, Rachel E. Drapeau

Theses and Dissertations

X-ray diffraction analysis (XRD) is an inexpensive method to quantify the relative proportions of mineral phases in a rock or soil sample. However, the analytical software available for XRD requires extensive user input to choose phases to include in the analysis. Consequently, analysis accuracy depends greatly on the experience of the analyst, especially as the number of phases in a sample increases (Raven & Self, 2017; Omotoso, 2006). The purpose of this project is to test whether incorporating machine learning methods into XRD software can improve the accuracy of analyses by assisting in the phase-picking process. In order to provide …

Go to article

Groundwater Flow Across The Coyote Wash Fault And Cedar Mesa Anticline Near St. Johns, Arizona, Stephanie Lynn Latour Aug 2023

Groundwater Flow Across The Coyote Wash Fault And Cedar Mesa Anticline Near St. Johns, Arizona, Stephanie Lynn Latour

Theses and Dissertations

As the demand for water increases across the southwestern United States, the region's utilization of and dependence on water stored in groundwater aquifers has risen in kind. The Coconino Aquifer (C-aquifer) underlies much of the southwestern Colorado Plateau and is a primary source of groundwater in northeastern Arizona. One of the largest commercial users of water from the C-aquifer in Apache County, Arizona, is Springerville Generating Station, a coal-fired power plant owned and operated by Tucson Electric Power. The area surrounding the power plant, located between the cities of Springerville and St. Johns, Arizona (the Springerville-St. Johns area), is geologically …

Go to article

Geochemistry Of Zircon And Apatite In Rhyolites From The Central Snake River Plain: Genetic Implications, Chesley Philip Gale Aug 2023

Geochemistry Of Zircon And Apatite In Rhyolites From The Central Snake River Plain: Genetic Implications, Chesley Philip Gale

Theses and Dissertations

Whole-rock and mineral compositions of three eruptive deposits from the Twin Falls caldera, associated with the Yellowstone hotspot, provide a window into melt generation and evolution for hot, dry, A-type rhyolites. Three rhyolitic units were sampled via the Kimberly drill-core as a part of project HOTSPOT, a study focused on mantle plume and continental lithosphere interaction. Previous work has been done to collect high resolution U-Pb zircon ages, and Hf- and O-isotopic compositions. This study examined the geochemistry of apatite and zircon along with host rock compositions in the context of this previous work. The Kimberly core sampled the Shoshone …

Go to article

Exploring New Horizons In Microwave-Promoted Iminyl Radical Chemistry And Synthesis Of Bulky Dehydroamino Acids, Jatinder Singh Aug 2023

Exploring New Horizons In Microwave-Promoted Iminyl Radical Chemistry And Synthesis Of Bulky Dehydroamino Acids, Jatinder Singh

Theses and Dissertations

The first project in this dissertation presents a simplified and efficient protocol for synthesizing pyrrolines through 5-exo iminyl radical cyclizations. The microwave irradiation of O-Phenyloximes tethered to alkenes causes N-O homolysis resulting in iminyl radical generation, which subsequently undergoes 5-exo-trig cyclizations furnishing pyrrolines. This eliminates the need for toxic radical initiators (AIBN, benzoyl peroxide), propagating agents (Bu3SnH, (Me3Si)3SiH), and expensive catalysts or single-electron transfer (SET) cycles. We explored the scope of diverse traps and substrates for iminyl radical cyclizations. The iminyl radical cyclizations formed versatile pyrrolines with moderate to excellent yields. The diastereoselectivity also ranged from low to high. Moreover, …

Go to article

Managing The Rock Mass Destruction Under The Explosion, Maksym Kononenko, Oleh Khomenko, Ivan Sadovenko, Valeriy Sobolev, Yuliya Pazynich, Adam Smoliński Aug 2023

Managing The Rock Mass Destruction Under The Explosion, Maksym Kononenko, Oleh Khomenko, Ivan Sadovenko, Valeriy Sobolev, Yuliya Pazynich, Adam Smoliński

Journal of Sustainable Mining

Using the theory of elasticity and the main provisions of the quasi-static-wave hypothesis of the mechanism of the destruction of a solid medium under the action of an explosion, analytical modelling of the parameters of the formation of crumpling zones and crushing of the rock mass around the charging cavity during its explosive loading was carried out. Analytical models of the radii of the crumpling, intensive fragmentation and fracturing zones formed around the charging cavity in the rock mass during its explosive loading, taking into account the pressure of the explosion products, the limit of tensile-compressive strength of the rocks, …

Go to article

On The Boundary Of The Cosmos, Daniel Linford Aug 2023

On The Boundary Of The Cosmos, Daniel Linford

Chemistry Department: Faculty Publications

Intuitively, the totality of physical reality – the Cosmos – has a beginning only if (i) all parts of the Cosmos agree on the direction of time (the Direction Condition) and (ii) there is a boundary to the past of all non-initial spacetime points such that there are no spacetime points to the past of the boundary (the Boundary Condition). Following a distinction previously introduced by J. Brian Pitts, the Boundary Condition can be conceived of in two distinct ways: either topologically, i.e., in terms of a closed boundary, or metrically, i.e., in terms of the Cosmos having a finite …

Go to article

Measures And Models Of Visual Acuity In Epipelagic And Mesopelagic Teleosts And Elasmobranchs, Eleanor M. Caves, Tracey Sutton, Eric J. Warrant, Sönke Johnsen Aug 2023

Measures And Models Of Visual Acuity In Epipelagic And Mesopelagic Teleosts And Elasmobranchs, Eleanor M. Caves, Tracey Sutton, Eric J. Warrant, Sönke Johnsen

Marine & Environmental Sciences Faculty Articles

Eyes in low-light environments typically must balance sensitivity and spatial resolution. Vertebrate eyes with large "pixels" (e.g., retinal ganglion cells with inputs from many photoreceptors) will be sensitive but provide coarse vision. Small pixels can render finer detail, but each pixel will gather less light, and thus have poor signal relative-to-noise, leading to lower contrast sensitivity. This balance is particularly critical in oceanic species at mesopelagic depths (200–1000 m) because they experience low light and live in a medium that significantly attenuates contrast. Depending on the spatial frequency and inherent contrast of a pattern being viewed, the viewer’s pupil size …

Go to article

Electrically Induced Cancellation And Inversion Of Piezoelectricity In Ferroelectric Hf0.5Zr0.5O2, Haidong Lu, Dong-Jik Kim, Hugo Aramberri, Marco Holzer, Pratyush Buragohain, Sangita Dutta, Uwe Schroeder, Veeresh Deshpande, Jorge Íñiguez, Alexei Gruverman, Catherine Dubourdieu Aug 2023

Electrically Induced Cancellation And Inversion Of Piezoelectricity In Ferroelectric Hf0.5Zr0.5O2, Haidong Lu, Dong-Jik Kim, Hugo Aramberri, Marco Holzer, Pratyush Buragohain, Sangita Dutta, Uwe Schroeder, Veeresh Deshpande, Jorge Íñiguez, Alexei Gruverman, Catherine Dubourdieu

Department of Physics and Astronomy: Faculty Publications

HfO2-based thin films hold huge promise for integrated devices as they show full compatibility with semiconductor technologies and robust ferroelectric properties at nanometer scale. While their polarization switching behavior has been widely investigated, their electromechanical response received much less attention so far. Here, we demonstrate that piezoelectricity in Hf0.5Zr0.5O2 ferroelectric capacitors is not an invariable property but, in fact, can be intrinsically changed by electrical field cycling. Hf0.5Zr0.5O2 capacitors subjected to ac cycling undergo a continuous transition from a positive effective piezoelectric coefficient d33 in the pristine state to …

Go to article

Whistler-Mode Waves In Magnetic Ducts, Anatoly V. Streltsov, Salman A. Nejad Aug 2023

Whistler-Mode Waves In Magnetic Ducts, Anatoly V. Streltsov, Salman A. Nejad

Publications

Observations from the NASA MMS satellites show packages of ELF whistler-mode waves localized inside the small-scale irregularities of the magnetic field. These irregularities are formed by the narrow field-aligned channels where the magnitude of the background magnetic field inside the channel is greater or less than outside. By analogy with the classical density ducts, we introduce the high-B duct (HBD), where the magnitude of the field inside the channel is greater than the outside, and the low-B duct (LBD), where the magnitude of the field inside the channel is less than the outside. We investigate the guiding of the ELF …

Go to article

First Prev Next Last