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Articles 1 - 30 of 3434

Full-Text Articles in Nanoscience and Nanotechnology

Piezo-Tribo Dual Effect Hybrid Nanogenerators For Health Monitoring, Sk Md Ali Zaker Shawon, Andrew Xu Sun, Valeria Suarez Vega, Brishty Deb Chowdhury, Phong Tran, Zaida D. Carballo, Jim Aica Tolentino, Jianzhi Li, Muhammad Sufian Rafaqut, Serena Danti, Mohammed Jasim Uddin Apr 2021

Piezo-Tribo Dual Effect Hybrid Nanogenerators For Health Monitoring, Sk Md Ali Zaker Shawon, Andrew Xu Sun, Valeria Suarez Vega, Brishty Deb Chowdhury, Phong Tran, Zaida D. Carballo, Jim Aica Tolentino, Jianzhi Li, Muhammad Sufian Rafaqut, Serena Danti, Mohammed Jasim Uddin

Electrical and Computer Engineering Faculty Publications and Presentations

Over the years, nanogenerators for health monitoring have become more and more attractive as they provide a cost-effective and continuous way to successfully measure vital signs, physiological status, and environmental changes in/around a person. Using such sensors can positively affect the way healthcare workers diagnose and prevent life-threatening conditions. Recently, the dual piezo-tribological effect of hybrid nanogenerators (HBNGs) have become a subject of investigation, as they can provide a substantial amount of data, which is significant for healthcare. However, real-life exploitation of these HBNGs in health monitoring is still marginal. This review covers piezo-tribo dual-effect HBNGs that are used ...


Nanopore Guided Regional Assembly, Eleni Adam, Desh Ranjan, Harold Riethman Apr 2021

Nanopore Guided Regional Assembly, Eleni Adam, Desh Ranjan, Harold Riethman

College of Sciences Posters

The telomeres are the “caps” of the chromosomes and their vital role is to protect them. Possible telomere dysfunction caused by telomere rearrangements can be fatal for the cell and result in age-related diseases, including cancer. The telomeres and subtelomeres are regions that are hard to investigate. The current technology cannot provide their complete sequence, instead the DNA is given in multiple pieces. Current methods of assembling the pieces of these regions are not accurate enough due to the region’s high variability and complex repeated patterns. We propose a hybrid assembly method, the NPGREAT, which utilizes two of the ...


Protein-Assisted Scalable Mechanochemical Exfoliation Of Few-Layer Biocompatible Graphene Nanosheets, Deepak-George Thomas, Steven De-Alwis, Shalabh Gupta, Vitalij K. Pecharsky, Deyny Mendivelso-Perez, Reza Montazami, Emily A. Smith, Nicole N. Hashemi Mar 2021

Protein-Assisted Scalable Mechanochemical Exfoliation Of Few-Layer Biocompatible Graphene Nanosheets, Deepak-George Thomas, Steven De-Alwis, Shalabh Gupta, Vitalij K. Pecharsky, Deyny Mendivelso-Perez, Reza Montazami, Emily A. Smith, Nicole N. Hashemi

Mechanical Engineering Publications

A facile method to produce few-layer graphene (FLG) nanosheets is developed using protein-assisted mechanical exfoliation. The predominant shear forces that are generated in a planetary ball mill facilitate the exfoliation of graphene layers from graphite flakes. The process employs a commonly known protein, bovine serum albumin (BSA), which not only acts as an effective exfoliation agent but also provides stability by preventing restacking of the graphene layers. The latter is demonstrated by the excellent long-term dispersibility of exfoliated graphene in an aqueous BSA solution, which exemplifies a common biological medium. The development of such potentially scalable and toxin-free methods is ...


Nanocellulose Sheets From Oil Palm Empty Fruit Bunches Treated With Naoh Solution, Farah Fahma, Faiza Ayu Lestari, Ika Amalia Kartika, Nurmalisa Lisdayana, Evi Savitri Iriani Mar 2021

Nanocellulose Sheets From Oil Palm Empty Fruit Bunches Treated With Naoh Solution, Farah Fahma, Faiza Ayu Lestari, Ika Amalia Kartika, Nurmalisa Lisdayana, Evi Savitri Iriani

Karbala International Journal of Modern Science

The objective of this study is to produce nanocellulose sheets from oil palm empty fruit bunches (OPEFBs). Nanocellulose sheets from OPEFBs were prepared through the dewatering process using vacuum filtration. Subsequently, the produced sheets were treated with NaOH solution to improve the mechanical stability of their structure, causing them to be firm in water. The water absorption of nanocellulose sheet increased with increasing NaOH concentrations up to 20 wt%, increasing tensile strength, and Young’s modulus, but decreased when they were treated with 30 wt%. The diameter shrinkage of nanocellulose sheets was directly proportional to the NaOH concentration and soaking ...


The Surface Chemistry And Structure Of Colloidal Lead Halide Perovskite Nanocrystals, Sara R. Smock, Yunhua Chen, Aaron J. Rossini, Richard L. Brutchey Feb 2021

The Surface Chemistry And Structure Of Colloidal Lead Halide Perovskite Nanocrystals, Sara R. Smock, Yunhua Chen, Aaron J. Rossini, Richard L. Brutchey

Chemistry Publications

Since the initial discovery of colloidal lead halide perovskite nanocrystals, there has been significant interest placed on these semiconductors because of their remarkable optoelectronic properties, including very high photoluminescence quantum yields, narrow size- and composition-tunable emission over a wide color gamut, defect tolerance, and suppressed blinking. These material attributes have made them attractive components for next-generation solar cells, light emitting diodes, low-threshold lasers, single photon emitters, and X-ray scintillators. While a great deal of research has gone into the various applications of colloidal lead halide perovskite nanocrystals, comparatively little work has focused on the fundamental surface chemistry of these materials ...


Elucidating The Location Of Cd2+ In Post-Synthetically Treated Inp Quantum Dots Using Dynamic Nuclear Polarization 31p And 113cd Solid-State Nmr Spectroscopy, Michael P. Hanrahan, Jennifer L. Stein, Nayon Park, Brandi M. Cossairt, Aaron J. Rossini Jan 2021

Elucidating The Location Of Cd2+ In Post-Synthetically Treated Inp Quantum Dots Using Dynamic Nuclear Polarization 31p And 113cd Solid-State Nmr Spectroscopy, Michael P. Hanrahan, Jennifer L. Stein, Nayon Park, Brandi M. Cossairt, Aaron J. Rossini

Chemistry Publications

Indium phosphide quantum dots (InP QD) are a promising alternative to traditional QD materials that contain toxic heavy elements such as lead and cadmium. However, InP QD obtained from colloidal synthesis are often plagued by poor photoluminescence quantum yields (PL-QYs). In order to improve the PL-QY of InP QD, a number of post-synthetic treatments have been devised. Recently, it has been shown that InP post-synthetically treated with Lewis acid metal divalent cations (M-InP) exhibit enhanced PL-QY; however, the molecular structure and mechanism behind the improved PL-QY are not fully understood. To determine the surface structure of M-InP QD, dynamic nuclear ...


Competitive Formation Of Intercalated Versus Supported Metal Nanoclusters During Deposition On Layered Materials With Surface Point Defects, Yong Han, Ann Lii-Rosales, Michael C. Tringides, James W. Evans Jan 2021

Competitive Formation Of Intercalated Versus Supported Metal Nanoclusters During Deposition On Layered Materials With Surface Point Defects, Yong Han, Ann Lii-Rosales, Michael C. Tringides, James W. Evans

Ames Laboratory Accepted Manuscripts

Intercalated metal nanoclusters (NCs) can be formed under the surface of graphite after sputtering to generate surface “portal” defects that allow deposited atoms to reach the subsurface gallery. However, there is a competition between formation of supported NCs on top of the surface and intercalated NCs under the surface, the latter only dominating at sufficiently high temperature. A stochastic model incorporating appropriate system thermodynamics and kinetics is developed to capture this complex and competitive nucleation and growth process. Kinetic Monte Carlo simulation shows that the model captures experimental trends observed for Cu and other metals and reveals that higher temperatures ...


Nondestructive Evaluation Of Aluminium Foam Panels Subjected To Impact Loading, Gabriella Epasto, Fabio Distefano, Hozhabar Mozafari, Emanoil Linul, Vincenzo Crupi Jan 2021

Nondestructive Evaluation Of Aluminium Foam Panels Subjected To Impact Loading, Gabriella Epasto, Fabio Distefano, Hozhabar Mozafari, Emanoil Linul, Vincenzo Crupi

Mechanical & Materials Engineering Faculty Publications

Aluminium foam sandwich structures have excellent energy absorption capacity, combined with good mechanical properties and low density. Some of the authors of this paper proposed an innovative Metallic Foam Shell protective device against flying ballast impact damage in railway axles. A closed-cell aluminium foam was chosen for the Metallic Foam Shell device. The main goal of this study was the experimental investigation of the impact responses of aluminium foam panels. Low velocity impact tests were carried out at different energies on different types of aluminium foam panels in order to investigate the effects of some parameters, such as core thickness ...


Metallic Surface Doping Of Metal Halide Perovskites, Yuze Lin, Yuchuan Shao, Jun Dai, Tao Li, Yi Liu, Xuezeng Dai, Xun Xiao, Yehao Deng, Alexei Gruverman, Xiao Cheng Zeng, Jinsong Huang Jan 2021

Metallic Surface Doping Of Metal Halide Perovskites, Yuze Lin, Yuchuan Shao, Jun Dai, Tao Li, Yi Liu, Xuezeng Dai, Xun Xiao, Yehao Deng, Alexei Gruverman, Xiao Cheng Zeng, Jinsong Huang

Mechanical & Materials Engineering Faculty Publications

Intentional doping is the core of semiconductor technologies to tune electrical and optical properties of semiconductors for electronic devices, however, it has shown to be a grand challenge for halide perovskites. Here, we show that some metal ions, such as silver, strontium, cerium ions, which exist in the precursors of halide perovskites as impurities, can n-dope the surface of perovskites from being intrinsic to metallic. The low solubility of these ions in halide perovskite crystals excludes the metal impurities to perovskite surfaces, leaving the interior of perovskite crystals intrinsic. Computation shows these metal ions introduce many electronic states close to ...


Surface Strengthening Of Single-Crystal Alumina By High-Temperature Laser Shock Peening, Fei Wang, X. L. Yan, Lei Liu, Michael Nastasi, Yongfeng Lu, Bai Cui Jan 2021

Surface Strengthening Of Single-Crystal Alumina By High-Temperature Laser Shock Peening, Fei Wang, X. L. Yan, Lei Liu, Michael Nastasi, Yongfeng Lu, Bai Cui

Mechanical & Materials Engineering Faculty Publications

This manuscript reports a novel process of high-temperature laser shock peening (HTLSP) for surface strengthening of single-crystal ceramics such as sapphire and reveals its fundamental mechanisms. HTLSP at 1200°C can induce a high compressive residual stress on the surface of sapphire while minimize the damage of laser-driven shock waves. Transmission electron microscopy characteriza- tions revealed high dislocation densities near the surface, suggesting that plastic deformation at an ultrahigh strain rate was generated by the high shock wave pressure. The HTLSP-induced compres- sive residual stress can significantly improve the hardness and fracture toughness of sapphire, while maintain its outstanding optical ...


Process-Structure Relationship In The Directed Energy Deposition Of Cobalt-Chromium Alloy (Stellite 21) Coatings, Ziyad M. Smoqi, Joshua Toddy, Harold (Scott) Halliday, Jeffrey E. Shield, Prahalada K. Rao Jan 2021

Process-Structure Relationship In The Directed Energy Deposition Of Cobalt-Chromium Alloy (Stellite 21) Coatings, Ziyad M. Smoqi, Joshua Toddy, Harold (Scott) Halliday, Jeffrey E. Shield, Prahalada K. Rao

Mechanical & Materials Engineering Faculty Publications

In this work, we accomplished the crack-free directed energy deposition (DED) of a multi-layer Cobalt- Chromium alloy coating (Stellite 21) on Inconel 718 substrate. Stellite alloys are used as coating materials given their resistance to wear, corrosion, and high temperature. The main challenge in DED of Stellite coatings is the proclivity for crack formation during printing. The objective of this work is to characterize the effect of the input energy density and localized laser-based preheating on the characteristics of the deposited coating, namely, crack formation, microstructural evolution, dilution of the coating composition due to diffusion of iron and nickel from ...


The Role Of Microenvironmental Cues And Mechanical Loading Milieus In Breast Cancer Cell Progression And Metastasis, Brandon D. Riehl, Eunju Kim, Tasneem Bouzid, Jung Yul Lim Jan 2021

The Role Of Microenvironmental Cues And Mechanical Loading Milieus In Breast Cancer Cell Progression And Metastasis, Brandon D. Riehl, Eunju Kim, Tasneem Bouzid, Jung Yul Lim

Mechanical & Materials Engineering Faculty Publications

Cancer can disrupt the microenvironments and mechanical homeostatic actions in multiple scales from large tissue modification to altered cellular signaling pathway in mechanotransduction. In this review, we highlight recent progresses in breast cancer cell mechanobiology focusing on cell-microenvironment interaction and mechanical loading regulation of cells. First, the effects of microenvironmental cues on breast cancer cell progression and metastasis will be reviewed with respect to substrate stiffness, chemical/topographic substrate patterning, and 2D vs. 3D cultures. Then, the role of mechanical loading situations such as tensile stretch, compression, and flow-induced shear will be discussed in relation to breast cancer cell mechanobiology ...


Surface Acoustic Waves Increase Magnetic Domain Wall Velocity, Anil Adhikari, Shireen Adenwalla Jan 2021

Surface Acoustic Waves Increase Magnetic Domain Wall Velocity, Anil Adhikari, Shireen Adenwalla

Shireen Adenwalla Papers

Domain walls in magnetic thin films are being explored for memory applications and the speed at which they move has acquired increasing importance. Magnetic fields and currents have been shown to drive domain walls with speeds exceeding 500 m/s. We investigate another approach to increase domain wall velocities, using high frequency surface acoustic waves to create standing strain waves in a 3 micron wide strip of magnetic film with perpendicular anisotropy. Our measurements, at a resonant frequency of 248.8 MHz, indicate that domain wall velocities increase substantially, even at relatively low applied voltages. Our findings suggest that the ...


All-Graphene-Based Open Fluidics For Pumpless, Small-Scale Fluid Transport Via Laser-Controlled Wettability Patterning, Lucas S. Hall, Dohgyu Hwang, Bolin Chen, Bryan Van Belle, Zachary T. Johnson, John A. Hondred, Carmen L. Gomes, Michael D. Bartlett, Jonathan C. Claussen Jan 2021

All-Graphene-Based Open Fluidics For Pumpless, Small-Scale Fluid Transport Via Laser-Controlled Wettability Patterning, Lucas S. Hall, Dohgyu Hwang, Bolin Chen, Bryan Van Belle, Zachary T. Johnson, John A. Hondred, Carmen L. Gomes, Michael D. Bartlett, Jonathan C. Claussen

Mechanical Engineering Publications

Open microfluidics have emerged as a low-cost, pumpless alternative strategy to conventional microfluidics for delivery of fluid for a wide variety of applications including rapid biochemical analysis and medical diagnosis. However, creating open microfluidics by tuning the wettability of surfaces typically requires sophisticated cleanroom processes that are unamenable to scalable manufacturing. Herein, we present a simple approach to develop open microfluidic platforms by manipulating the surface wettability of spin-coated graphene ink films on flexible polyethylene terephthalate via laser-controlled patterning. Wedge-shaped hydrophilic tracks surrounded by superhydrophobic walls are created within the graphene films by scribing micron-sized grooves into the graphene with ...


Sense–Analyze–Respond–Actuate (Sara) Paradigm: Proof Of Concept System Spanning Nanoscale And Macroscale Actuation For Detection Of Escherichia Coli In Aqueous Media, Cassie A. Giacobassi, Daniela A. Oliveira, Cicero C. Pola, Dong Xiang, Yifan Tang, Shoumen Palit Austin Datta, Eric S. Mclamore, Carmen L. Gomes Jan 2021

Sense–Analyze–Respond–Actuate (Sara) Paradigm: Proof Of Concept System Spanning Nanoscale And Macroscale Actuation For Detection Of Escherichia Coli In Aqueous Media, Cassie A. Giacobassi, Daniela A. Oliveira, Cicero C. Pola, Dong Xiang, Yifan Tang, Shoumen Palit Austin Datta, Eric S. Mclamore, Carmen L. Gomes

Mechanical Engineering Publications

Foodborne pathogens are a major concern for public health. We demonstrate for the first time a partially automated sensing system for rapid (~17 min), label-free impedimetric detection of Escherichia coli spp. in food samples (vegetable broth) and hydroponic media (aeroponic lettuce system) based on temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm) nanobrushes. This proof of concept (PoC) for the Sense-Analyze-Respond-Actuate (SARA) paradigm uses a biomimetic nanostructure that is analyzed and actuated with a smartphone. The bio-inspired soft material and sensing mechanism is inspired by binary symbiotic systems found in nature, where low concentrations of bacteria are captured from complex matrices by brush actuation ...


Generation Of Excited Species In A Streamer Discharge, Shirshak K. Dhali Jan 2021

Generation Of Excited Species In A Streamer Discharge, Shirshak K. Dhali

Electrical & Computer Engineering Faculty Publications

At or near atmospheric pressure, most transient discharges, particularly in molecular gases or gas mixture containing molecular gases, result in a space charge dominated transport called a streamer discharge. The excited species generation in such discharges forms the basis for plasma chemistry in most technological applications. In this paper, we simulate the propagation of streamers in atmospheric pressure N2 to understand the energy partitioning in the formation of various excited species and compare the results to a uniform Townsend discharge. The model is fully two-dimensional with azimuthal symmetry. The results show a significantly larger fraction of the energy goes ...


Revealing The Surface Structure Of Cdse Nanocrystals By Dynamic Nuclear Polarization-Enhanced 77se And 113cd Solid-State Nmr Spectroscopy, Yunhua Chen, Rick W. Dorn, Michael P. Hanrahan, Lin Wei, Rafael Blome-Fernández, Alan M. Medina-Gonzalez, Marquix A. S. Adamson, Anne H. Flintgruber, Javier Vela, Aaron J. Rossini Jan 2021

Revealing The Surface Structure Of Cdse Nanocrystals By Dynamic Nuclear Polarization-Enhanced 77se And 113cd Solid-State Nmr Spectroscopy, Yunhua Chen, Rick W. Dorn, Michael P. Hanrahan, Lin Wei, Rafael Blome-Fernández, Alan M. Medina-Gonzalez, Marquix A. S. Adamson, Anne H. Flintgruber, Javier Vela, Aaron J. Rossini

Chemistry Publications

Dynamic nuclear polarization (DNP) solid-state NMR (SSNMR) spectroscopy was used to obtain detailed surface structures of zinc blende CdSe nanocrystals (NCs) with plate or spheroidal morphologies and which are capped by carboxylic acid ligands. 1D 113Cd and 77Se cross-polarization magic angle spinning (CPMAS) NMR spectra revealed distinct signals from Cd and Se atoms on the surface of the NCs, and those residing in bulk-like environments below the surface. 113Cd cross-polarization magic-angle-turning (CP-MAT) experiments identified CdSe3O, CdSe2O2, and CdSeO3 Cd coordination environments on the surface of the NCs, where the oxygen atoms are presumably from coordinated carboxylate ligands. The sensitivity gain ...


Treated Hfo2 Based Rram Devices With Ru, Tan, Tin As Top Electrode For In-Memory Computing Hardware, Yuvraj Dineshkumar Patel Dec 2020

Treated Hfo2 Based Rram Devices With Ru, Tan, Tin As Top Electrode For In-Memory Computing Hardware, Yuvraj Dineshkumar Patel

Theses

The scalability and power efficiency of the conventional CMOS technology is steadily coming to a halt due to increasing problems and challenges in fabrication technology. Many non-volatile memory devices have emerged recently to meet the scaling challenges. Memory devices such as RRAMs or ReRAM (Resistive Random-Access Memory) have proved to be a promising candidate for analog in memory computing applications related to inference and learning in artificial intelligence. A RRAM cell has a MIM (Metal insulator metal) structure that exhibits reversible resistive switching on application of positive or negative voltage. But detailed studies on the power consumption, repeatability and retention ...


Silicon Nanocrystals As Signal Transducers In Ionophore-Based Fluorescent Nanosensors, Mark S. Ferris, Ashley P. Chesney, Bradley J. Ryan, Utkarsh Ramesh, Matthew G. Panthani, Kevin J. Cash Dec 2020

Silicon Nanocrystals As Signal Transducers In Ionophore-Based Fluorescent Nanosensors, Mark S. Ferris, Ashley P. Chesney, Bradley J. Ryan, Utkarsh Ramesh, Matthew G. Panthani, Kevin J. Cash

Chemical and Biological Engineering Publications

Colloidal silicon crystallites in the size range of 1-12 nm, also referred to as “silicon nanocrystals” have unique optical properties that include high quantum efficiency, size-dependent emission spanning the visible to near-infrared range, and robust photostability. These features, combined with silicon’s high earth-abundance and good biocompatibility, make them an attractive option to serve as signal transduction elements in bioanalytical sensors. In this study, we combine silicon nanocrystals with a sodium-selective ionophore and a charge balancing additive in polymeric nanosensors to create a Silicon Nanocrystal NanoSensor (SiNC-NS). The SiNC-NS responded to sodium through a decrease in fluorescence intensity without the ...


Interface Engineering Of Materials For Energy And Biological Applications, Ardalan Chaichi Dec 2020

Interface Engineering Of Materials For Energy And Biological Applications, Ardalan Chaichi

LSU Doctoral Dissertations

Interface interactions are generally classified into solid-liquid, solid-gas, solid-vacuum, liquid-gas, light-matter and electron-matter categories. Surface morphological studies as well as surface chemical reactions can be studied in various types of complex systems thanks to technological advances in materials characterization methods. By employing interface engineering in different applications, it is possible to control electrical, chemical, mechanical, optical and biological properties of materials. Accordingly, we have applied interface engineering in three different areas of energy materials, biomaterials and surface imaging. As a result, firstly, we have introduced a high intensity light flash-based method on engineered substrates for delamination of reduced graphene oxide ...


Activation And Assembly Of Plasmonic-Magnetic Nanosurfactants For Encapsulation And Triggered Release, Fei Liu, Yifan Li, Yanhua Huang, Ayuna Tsyrenova, Kyle Miller, Lin Zhou, Hantang Qin, Shan Jiang Dec 2020

Activation And Assembly Of Plasmonic-Magnetic Nanosurfactants For Encapsulation And Triggered Release, Fei Liu, Yifan Li, Yanhua Huang, Ayuna Tsyrenova, Kyle Miller, Lin Zhou, Hantang Qin, Shan Jiang

Materials Science and Engineering Publications

Multifunctional surfactants hold great potentials in catalysis, separation, and biomedicine. Highly active plasmonic-magnetic nanosurfactants are developed through a novel acid activation treatment of Au–Fe3O4 dumbbell nanocrystals. The activation step significantly boosts nanosurfactant surface energy and enables the strong adsorption at interfaces, which reduces the interfacial energy one order of magnitude. Mediated through the adsorption at the emulsion interfaces, the nanosurfactants are further constructed into free-standing hierarchical structures, including capsules, inverse capsules, and two-dimensional sheets. The nanosurfactant orientation and assembly structures follow the same packing parameter principles of surfactant molecules. Furthermore, nanosurfactants demonstrate the capability to disperse and encapsulate homogeneous ...


Applications Of Cathodoluminescence In Plasmonic Nanostructures And Ultrathin Inas Quantum Layers, Qigeng Yan Dec 2020

Applications Of Cathodoluminescence In Plasmonic Nanostructures And Ultrathin Inas Quantum Layers, Qigeng Yan

Theses and Dissertations

Due to the advanced focusing ability, characterization methods based on the electron-beam excitation have been broadly applied to investigate nanomaterials. Structural or compositional information is commonly acquired using electron microscopes. Moreover, taking advantage of the super spatial resolution of the focused electron beam, optical properties of nanomaterials can be also obtained. Herein, general concepts and processes of the interaction between electrons and materials are studied. Two specific optical nanomaterials, including plasmonic nanostructures and semiconductor quantum layers, are investigated by the cathodoluminescence (CL) measurement.

Surface plasmonic resonance can be generated when high-energy electrons strike the interface between the dielectric medium and ...


3-D Fabry–Pérot Cavities Sculpted On Fiber Tips Using A Multiphoton Polymerization Process, Jonathan W. Smith, Jeremiah C. Williams, Joseph S. Suelzer, Nicholas G. Usechak, Hengky Chandrahalim Dec 2020

3-D Fabry–Pérot Cavities Sculpted On Fiber Tips Using A Multiphoton Polymerization Process, Jonathan W. Smith, Jeremiah C. Williams, Joseph S. Suelzer, Nicholas G. Usechak, Hengky Chandrahalim

Faculty Publications

This paper presents 3-D Fabry–Pérot (FP) cavities fabricated directly onto cleaved ends of low-loss optical fibers by a two-photon polymerization (2PP) process. This fabrication technique is quick, simple, and inexpensive compared to planar microfabrication processes, which enables rapid prototyping and the ability to adapt to new requirements. These devices also utilize true 3-D design freedom, facilitating the realization of microscale optical elements with challenging geometries. Three different device types were fabricated and evaluated: an unreleased single-cavity device, a released dual-cavity device, and a released hemispherical mirror dual-cavity device. Each iteration improved the quality of the FP cavity's reflection ...


Optical Properties Of Ultrathin In(Ga)As/Gaas And In(Ga)N/Gan Quantum Wells, Yurii Maidaniuk Dec 2020

Optical Properties Of Ultrathin In(Ga)As/Gaas And In(Ga)N/Gan Quantum Wells, Yurii Maidaniuk

Theses and Dissertations

Recently, structures based on ultrathin quantum wells (QWs) began to play a critical role in modern devices, such as lasers, solar cells, infrared photodetectors, and light-emitting diodes. However, due to the lack of understanding of the formation mechanism of ultrathin QWs during the capping process, scientists and engineers cannot fully explore the potential of such structures. This study aims to investigate how structural parameters of ultrathin QWs affect their emission properties by conducting a systematic analysis of the optical properties of In(Ga)As/GaAs and In(Ga)N/GaN ultrathin QWs. Specifically, the analysis involved photoluminescence measurements combined with ...


Substrate–Support Interactions Mediate Hydrogenation Of Phenolic Compounds By Pd/Ceo2 Nanorods, Yeongseo An, Pranjali Naik, Igor I. Slowing, Vincenzo Venditti Nov 2020

Substrate–Support Interactions Mediate Hydrogenation Of Phenolic Compounds By Pd/Ceo2 Nanorods, Yeongseo An, Pranjali Naik, Igor I. Slowing, Vincenzo Venditti

Chemistry Publications

Ceria-supported palladium (Pd/CeO2) has spawned significant attention in recent years due to its ability to catalyze selective hydrogenation of phenolic compounds to cyclohexanones and cyclohexanols at a mild temperature and pressure. However, the mechanistic basis by which ceria enhances catalytic conversion is still unclear. Here, we use the increase in the 13C transverse relaxation rate upon the addition of nanoparticles (NPs) (13C ΔR2) to investigate the adsorption of phenolic compounds on the surface of the Pd/CeO2 catalyst by solution NMR. We show that hydroxyphenols adsorb on the support more efficiently than underivatized phenol and methoxyphenols and ...


Editorial: Carbon- And Inorganic-Based Nanostructures For Energy Applications, Federico Cesano, M. Jasim Uddin, Yuanbing Mao, Muhammad N. Huda Nov 2020

Editorial: Carbon- And Inorganic-Based Nanostructures For Energy Applications, Federico Cesano, M. Jasim Uddin, Yuanbing Mao, Muhammad N. Huda

Chemistry Faculty Publications and Presentations

No abstract provided.


Combustion Synthesis, Structural, Magnetic And Dielectric Properties Of Gd3+-Doped Lead Molybdato–Tungstates, T. Groń, M. Maciejkowicz, E. Tomaszewicz, M. Guzik, M. Oboz, B. Sawicki, S. Pawlus, A. Nowok, Z. Kukuła Oct 2020

Combustion Synthesis, Structural, Magnetic And Dielectric Properties Of Gd3+-Doped Lead Molybdato–Tungstates, T. Groń, M. Maciejkowicz, E. Tomaszewicz, M. Guzik, M. Oboz, B. Sawicki, S. Pawlus, A. Nowok, Z. Kukuła

Journal of Advanced Ceramics

Gd3+-doped lead molybdato–tungstates with the chemical formula of Pb1–3xħxGd2x(MoO4)1–3x(WO4)3x (where x = 0.0455, 0.0839, 0.1430, corresponding to 9.53, 18.32, 33.37 mol% of Gd3+, respectively, as well as ħ denotes cationic vacancies) were successfully synthesized via combustion route. The XRD and SEM results confirmed the formation of single-phase, tetragonal scheelite-type materials (space group I41/a) with the uniform, spherical and oval grains ranging from 5 to 20 μm. Individual grains are strongly agglomerated into big clusters with the ...


Ruddlesden-Popper Phase A2Bo4 Oxides: Recent Studies On Structure, Electrical, Dielectric, And Optical Properties, Gurudeo Nirala, Dharmendra Yadav, Shail Upadhyay Oct 2020

Ruddlesden-Popper Phase A2Bo4 Oxides: Recent Studies On Structure, Electrical, Dielectric, And Optical Properties, Gurudeo Nirala, Dharmendra Yadav, Shail Upadhyay

Journal of Advanced Ceramics

In the last two decades, structure and properties of Ruddlesden–Popper phase (RP) A2BO4 oxides with K2NiF4 structure, have been widely investigated. But to the best of our knowledge, no review article is available in the literature on recent studies on these oxides. Therefore, in this article, recent studies on structure, electrical, dielectric, and optical properties of these oxides have been reviewed. Special attention is put on to highlight the effect of doping and oxygen stoichiometry on the structure and properties of these oxides. Further, important applications of these oxides have also been mentioned ...


Structural, Thermomagnetic, And Dielectric Properties Of Mn0.5Zn0.5GdXFe2–XO4 (X = 0, 0.025, 0.050, 0.075, And 0.1), Lakshita Phor, Vinod Kumar Oct 2020

Structural, Thermomagnetic, And Dielectric Properties Of Mn0.5Zn0.5GdXFe2–XO4 (X = 0, 0.025, 0.050, 0.075, And 0.1), Lakshita Phor, Vinod Kumar

Journal of Advanced Ceramics

In this paper, effect of Gd3+ was investigated on structural, magnetic, and dielectric properties of Mn0.5Zn0.5GdxFe2–xO4 (x = 0, 0.025, 0.050, 0.075, and 0.1) nanoparticles prepared by facile coprecipitation method. X-ray diffraction (XRD) studies confirmed the single cubic spinel phase for all the samples and showed that lattice parameter (aexp) was found to increase from 8.414 to 8.446 Å with the substitution of Gd3+ ions due to their larger ionic radii than the replaced Fe3+ ions. Shape and size ...


Microstructure Modification Of Y2O3 Stabilized Zro2 Thermal Barrier Coatings By Laser Glazing And The Effects On The Hot Corrosion Resistance, Lei Guo, Hui Xin, Zhao Zhang, Xinmu Zhang, Fuxing Ye Oct 2020

Microstructure Modification Of Y2O3 Stabilized Zro2 Thermal Barrier Coatings By Laser Glazing And The Effects On The Hot Corrosion Resistance, Lei Guo, Hui Xin, Zhao Zhang, Xinmu Zhang, Fuxing Ye

Journal of Advanced Ceramics

Y2O3 stabilized ZrO2 (YSZ) thermal barrier coatings (TBCs) are prone to hot corrosion by molten salts. In this study, the microstructure of atmospheric plasma spraying YSZ TBCs is modified by laser glazing in order to improve the corrosion resistance. By optimizing the laser parameters, a ~18 μm smooth glazed layer with some vertical cracks was produced on the coating surfaces. The as-sprayed and modified coatings were both exposed to hot corrosion tests at 700 and 1000 ℃ for 4 h in V2O5 molten salt, and the results revealed that the modified one had improved ...