Bulletin of the American Physical Society
Joint Fall 2017 Meeting of the Texas Section of the APS, Texas Section of the AAPT, and Zone 13 of the Society of Physics Students
Volume 62, Number 16
Friday–Saturday, October 20–21, 2017; The University of Texas at Dallas, Richardson, Texas
Session L1: Poster Session II |
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Chair: Jason Slinker, University of Texas at Dallas Room: DGAC Texas Instruments Inspiration Hall |
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L1.00001: Superconductivity in Ta-doped Zr5Ge3 System Varun Anand, Sheng Li, Xiaoyuan Liu, Bing Lv Inspired by the discovery of first superconductor Zr5Sb3 in the large hexagonal Mn5Si3-type compounds, we have carried out systematical doping studies in the Ta-doped Zr5-xTaxGe3 (0 $\le $ x $\le $ 5) system. X-ray diffraction analysis has shown a clear phase transition from hexagonal Mn5Si3-type structure to tetragonal W5Si3-type structure occurring when x\textgreater 3. Superconductivity up to 4.5K is observed, on the other hand, when Ta doping level is 0.5$\le $x$\le $2. The superconductivity is further demonstrated from both magnetic and electrical resistivity measurements with type-II superconductors and upper critical field \textasciitilde 5000 Oe. The detailed synthesis and characterizations will be presented and discussed. [Preview Abstract] |
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L1.00002: Superconductivity in Ta-doped Zr$_{\mathrm{5}}$Ge$_{\mathrm{3}}$ System Varun Anand, Sheng Li, Xiaoyuan Liu, Bing Lv Inspired by the discovery of first superconductor Zr$_{\mathrm{5}}$Sb$_{\mathrm{3}}$ in the large hexagonal Mn$_{\mathrm{5}}$Si$_{\mathrm{3}}$-type compounds, we have carried out systematical doping studies in the Ta-doped Zr$_{\mathrm{5-x}}$Ta$_{\mathrm{x}}$Ge$_{\mathrm{3}}$ (0 $\le $ x $\le $ 5) system. X-ray diffraction analysis has shown a clear phase transition from hexagonal Mn$_{\mathrm{5}}$Si$_{\mathrm{3}}$-type structure to tetragonal W$_{\mathrm{5}}$Si$_{\mathrm{3}}$-type structure occurring when x\textgreater 3. Superconductivity up to 4.5K is observed, on the other hand, when Ta doping level is 0.5$\le $x$\le $2. The superconductivity is further demonstrated from both magnetic and electrical resistivity measurements with type-II superconductors and upper critical field \textasciitilde 5000 Oe. The detailed synthesis and characterizations will be presented and discussed. [Preview Abstract] |
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L1.00003: Determination of Valence State of Transition metal ions in Li(Fe, M)PO4 (M $=$ Cr, Ni, Ti, Cd, and V) Cathode Materials. Gan Liang, Hui Fang, Mark Croft, Lu-Lu Zhang A clear determination of the valence states of transition metal ions in cathode materials of lithium-ion batteries is important for understanding the improvement of electrochemical performance of cation doped LiFePO4 cathode materials. In this work, the x-ray absorption spectroscopy (XAS) determination of valence states of transition metal ions Cr, Ni, Ti, Fe, Cd, and V in Li(Fe, M)PO4 (with M $=$ Cr, Ni, Ti, Cd, and V) cathode materials is presented. Our XAS results clearly indicate that in these transition metal doped cathode materials, the valence values of Cr, Ni, Ti, Fe and Cd are $+$3, $+$2, $+$4, $+$2, and $+$3, respectively. The valence of V in V-doped LiFePO4, however, is between $+$3 and $+$4. The improvement of the electrochemical performance (or the increase of specific discharge capacity) due to the transition metal M for Fe doping for some transition metals M is discussed in association with the XAS results. [Preview Abstract] |
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L1.00004: Photoconductive response of ammonium nitrate crystals support on silica nanospring mats Lyndon Bastatas, Elena Echeverria-Mora, Aaron Austin, David McIlroy Nanostructures such as nanowires and nanosprings have high surface-to-volume ratio. They offer a wider active area for molecules to interact, which is favorable for chemical sensing. Ammonium nitrate exhibits photoconductivity and sensitivity to humidity. However, to precisely deposit the photoconductive film on the region of interest without providing scaffold for the film faces delamination issues. We intend to investigate the utility of silica-based nanosprings as a sensor when coated with ammonium nitrate. Preliminary studies are being conducted that take advantage of the hydrophilicity of nanosprings after plasma treatment. The current methodology for growing ammonium nitrate crystals involves soaking hydrophilic nanospring mats grown on a glass in a solution of ammonium nitrate and DI water, followed by air drying. The nanosprings act as the scaffold for nucleation of ammonium nitrate crystals and adhesion to the surface. Electrical characterization in air and at room temperature reveals sensitivity of the nanospring support ammonium nitrate crystals upon exposure to humidity and strong photoconductive response upon illumination for wavelengths less than or equal to 532 nm. [Preview Abstract] |
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L1.00005: Accelerating Undergraduate Research with GPU Computing Chris Curry, Bryan Hollingsworth, Weston Kimbro, Bobby Garza, Leika Otero Simple iterative equations known as mappings have been studied as models of plasma and fluid systems, particle accelerators, and the transition to chaos in dynamical systems. Maps contain rich behavior characteristic of more complicated systems and are much faster to compute than the full dynamics, but challenges exist in computing and visualizing many initial conditions in parallel. The latest advances in graphics processing unit (GPU) computing (CUDA, OpenCL) have made massively parallel processing tasks readily available and accelerated machine learning, physics simulations, and data science. GPUs are also well suited to Virtual Reality (VR) applications. Here we present some recent results using GPUs and iterative mappings for VR explorations, biological neural networks, and cryptography. [Preview Abstract] |
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L1.00006: Building K--12 Teacher Conceptual Physics Understanding and Teaching Toolkits through Long-Term Professional Development Mary Urquhart The Department of Science/Mathematics Education (SME) in the School of Natural Sciences and Mathematics of the University of Texas at Dallas (UTD) has several long-term professional development programs designed to build and strengthen teacher conceptual understanding simultaneously with pedagogical content knowledge, classroom-ready activities, and teaching resources. The Master of Arts (MAT) in Teaching Program in Science Education is designed for in-service teacher enhancement and secondary STEM teaching certification preparation through our UTeach Dallas/MAT partnership. The 9-credit hour MAT Conceptual Physics series brings together content experts and novices in a rich exploration of physics ideas and common barriers to understanding, integrated with practical strategies and resources. SME is also home to the UTD Texas Regional Collaboratives (TRC) for Excellence in Science and Mathematics Teaching. Through these grant-supported, content-focused programs we serve dozens of teachers each year. A UTD TRC partnership brought physics professional development directly to middle school teachers in one local high-needs school district. We will present on the structure of our programs, our successes and challenges, and our partnerships. We will also share some free resources! [Preview Abstract] |
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L1.00007: Differences in cognitive ability and academic motivation among three institutions Amanda Benson, Michael Greene, Ramon Lopez There is an abundance of evidence to suggest that mental rotation ability, scientific reasoning ability, and academic motivation all contribute to a student's performance in introductory calculus-based physics. Data was collected from the University of Texas at Arlington, Texas Christian University, and Yale University. We administered the Mental Rotation Test, and the Classroom Test of Scientific Reasoning, and the Motivated Strategies for Learning Questionnaire to students enrolled in introductory physics. In this study, we report descriptive statistics and statistical inferences of these measures among institutions. [Preview Abstract] |
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L1.00008: VIGOR: Virtual Interaction with Gravitational Waves to Observe Relativity Monisha Elumalai, Midori Kitagawa, Michael Kesden, Ngoc Tran, Thulasi Swamipillai, Mary Urquhart, Roger Malina In 2017 a century after Albert Einstein published his theory of general relativity, the Laser Interferometer Gravitational-wave Observatory (LIGO) detected gravitational waves from binary black holes fully consistent with this theory. Our goal for VIGOR (Virtual-reality Interaction with Gravitational waves to Observe Relativity) is to communicate this revolutionary discovery to the public by visualizing the gravitational waves emitted by binary black holes. VIGOR has been developed using the Unity game engine, handheld devices and VR headsets (Oculus Rift DK2 and Samsung Gear VR). Using an iPad or a VR device, VIGOR users control the earth to “fly” around binary black holes, experiment on the black holes by manipulating their total mass, mass ratio, and orbital sepa-ration, and witness how gravitational waves emitted by the black holes stretch and squeeze the earth. We evaluated our prototype of VIGOR with high school students in 2016 and 2017 and are further improving VIGOR based on our findings. [Preview Abstract] |
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L1.00009: Maximum Entropy Methods in Survival Analysis Joscelyne Guzman, Sorour Hosseini, Marian Manciu The fundamental problem of the traditional Biostatistics is to calculate the probability that an experimental result is due entirely to chance (the null hypothesis). When that probability is sufficiently low (typically, below 5 {\%}) it can be assumed that an underlying "effect" might explain the results (the alternate hypothesis), but in general the "effect" is not quantitatively determined. For example, in Survival Analysis there are a number of algorithms that can determine whether two groups have statistically significant different survivals (time-to-event distributions). However, the difference between the median survival times of the groups, which is typically reported, is not always a good estimator of the quantitative survival differences between groups. Even more important, when the populations of the groups are very small, there is almost impossible to obtain statistically significant differences between them, regardless of how strong the underlying "effect" might be. We suggest an alternative approach, in which we calculate the most likely "effect" that explains the given experimental outcome, namely the "effect" that maximizes the entropy of the result. It will be shown (via Monte-Carlo simulations) not only that such an estimator is in a very good agreement with the average survival time difference between the two groups, but also that it remains reasonably accurate even at low sample numbers, for which traditional Biostatistical methods suggest that the null hypothesis cannot be rejected. [Preview Abstract] |
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L1.00010: Topological photonic orbital angular momentum switch Xi-Wang Luo, Chuanwei Zhang, Guang-Can Guo, Zheng-Wei Zhou The large number of available orbital angular momentum (OAM) states of photons provides a unique resource for many important applications in quantum information and optical communications. However, conventional OAM switching devices usually rely on precise parameter control and are limited by slow switching rate and low efficiency. Here we propose a robust, fast and efficient photonic OAM switch device based on a topological process, where photons are adiabatically pumped to a target OAM state on demand. Such topological OAM pumping can be realized through manipulating photons in a few degenerate main cavities and involves only a limited number of optical elements. A large change of OAM at $\sim 10^{q}$ can be realized with only $q$ degenerate main cavities and at most $5q$ pumping cycles. The topological photonic OAM switch may become a powerful device for broad applications in many different fields. [Preview Abstract] |
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L1.00011: First-Principles Investigation of Isolated Ultra-Thin Noble-Metal Polyhedral Nanowires Sean Mullins, Xochitl Lopez-Lozano The theoretical investigation of high-stability structures at nanoscale is fundamental for the continuing development of novel nanomaterials. Ultra-thin nanowires are of great interest for they often have excellent mechanical, electrical, thermal, and optical properties, making them suitable for applications in nanodevices and nanomaterials for sensing, imaging, and cancer therapy. In this work we have performed Density Functional Theory (DFT) calculations to investigate the properties of gold and silver isolated nanowires using the SIESTA code. Our calculations show that nanowires configured with tetrahelical morphology exhibit metastability. When the tetrahelixes deform, a nanowire was obtained with octahedral components. Using these octahedrons as building blocks new polyhedral nanowires were constructed and optimized. A detailed description of their structural and electronic properties is presented. [Preview Abstract] |
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L1.00012: Theoretical Investigations, Structure, and the Ring-Puckering Vibration of 3-Oxabicyclo[3.1.0]hexane Lauren A. Wieding, Esther J. Ocola, Jaan Laane Ab initio computations using the MP2/cc-pVTZ method have been carried out to calculate the structures and energies of the conformations of 3-oxabicyclo[3.1.0]hexane (OBCH). A theoretical potential energy function for the ring-puckering vibration was also determined. The minimum energy conformation of OBCH has the ring puckering angle of the five-membered ring at a calculated value of 34.0 degrees and a three-membered ring bending angle of 69.2 degrees. The theoretical potential energy function and the experimental potential energy function, previously determined from spectroscopic data, are in good agreement. Both of these functions are asymmetric and have the conformation with the lowest energy puckered in the same direction as the attached three-membered ring. The calculations also show that the ring-puckering vibration is somewhat coupled to the ring-flapping and ring-twisting motions.~ The observed far-infrared ring-puckering transitions for OBCH agree with the calculated values to within 1{\%}. The wavefunctions for the lowest ring-puckering energy levels have also been computed. [Preview Abstract] |
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L1.00013: Constraining Cosmological Parameters with CosmoMC and CAMB: Dark Energy and the Accelerated Expansion of the Universe Logan Fox The Lambda-CDM model provides a simple, yet elegant, description of our universe. It can give us answers to questions such as: What is the energy density of the universe? Of this total density, how much is in the form of baryonic matter? What are the other components? When did large scale structures begin to form? In recent decades advances in computational and observational power have enabled us to answer these questions accurately in the form of constraints on the parameters of the Lambda-CDM model, and led us to an era of precision cosmology. Bayesian statistics, specifically maximum likelihood estimation, is used to translate the observed data into estimates of cosmological parameter values. CosmoMC, a Markov-Chain Monte-Carlo code, is used to produce marginalized posterior plots of the cosmological parameters, as well as 2D plots that give both quantitative and qualitative descriptions of parameter degeneracies and constraining power. CAMB is a Boltzmann solver code. The results of these constraints imply that dark energy is responsible for the accelerated expansion of the universe and that it is the dominant component of the energy density in the universe. It is extremely satisfying to be able to learn so much about our universe despite being such a small part of it. [Preview Abstract] |
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L1.00014: Self-consistent Simulation of Microparticle and Ion Wakefield Configuration Dustin Sanford, Naoki Ellis, Beau Brooks, Lorin Matthews, Truell Hyde Within a complex plasma, a directed flow of positively charged ions with respect to negatively charged dust grains often arises. The interactions between the streaming ions and dust particles generates an ion wakefield downstream from the dust particles. The resulting positive space region modifies interactions between the grains and contributes to the dynamics and equilibrium structure of the system. A molecular dynamics simulation is presented as a method for modeling ion wakefields that allows dust particle dynamics to be determined self-consistently. The trajectory of each ion is calculated including the forces from all other ions, which are treated as ``Yukawa particles'' and shielded from thermal electrons and charged dust particles. Both the dust grain charge and the wakefield structure are self-consistently determined for various particle configurations. The wakefields generated from statically positioned dust particles can be used to provide a self-consistent determination of dust particle positions. These results will be employed to analyze the formation and dynamics of field-aligned chains in CASPER'sPK4 experiment onboard the International Space Station, allowing examination of extended dust chains without the masking force of gravity. [Preview Abstract] |
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L1.00015: Antihydrogen Atom Formation via Capturing of Positron by Antiproton Beam Traveling Through Electron-Positron Plasma Cat Tran, Carlos Ordonez A simulation is created to study the formation of an antihydrogen atom via the capturing by an antiproton of a positron from an electron-positron magnetobound pair when it travels through an electron-positron plasma. A magnetobound pair of electron-positron is known as magnetobound positronium. It has been previously discovered through simulation that a collision between electron and positron pair can result in a giant-cross-magnetic field drift in a constant magnetic field (e.g 1 T). This drift is mutual and is orthogonal to the constant magnetic field. This simulation model is to show that, as an antiproton travels through a magnetobound positronium's proximity, the antiproton can capture the positron and form an antihydrogen atom; at the same time, the electron is expelled out of its positronium magnetobound state due to its opposite charge. The result is a guiding-center drift antihydrogen atom. [Preview Abstract] |
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L1.00016: Visualizing Non-Linear Dynamical Systems in Virtual Reality (VR) Bryan Hollingsworth, Weston Kimbro, Chris Curry To understand non-linear dynamical systems, we commonly use mapped out values to predict the behavior of the system. In the case of Virtual Reality, we can visualize beyond two-dimensional mappings which allows us to view complete three-dimensional systems or take three-dimensional Poincar\'{e} sections of higher dimension systems. We used a game engine, Unreal Engine 4, to model these systems and to help offload many calculations to our Graphics Processing Unit (GPU) without changes to the code. We now have a program that can model basic examples of non-linear dynamical systems and we continue to work toward modelling more complicated systems through this program. Once we can model any system, this program will be a useful tool in learning non-linear dynamics and we may find behaviors of various systems that we did not see before. [Preview Abstract] |
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L1.00017: Geant4 simulation of protons hitting different body materials and obtaining of the sensibility for gamma ray detectors. Omar Hernandez Rodriguez, Selim Romero, Jorge Lopez, Jason Holmes The purpose of this study in medical physics is to identify the difference in energies between the water's histogram and the body materials and calculate the sensitivity required for gamma ray detectors. The simulation was made with Geant4, that is, the bombardment of high energy protons in different materials. Different proton energies as well as different body materials were used as targets, thus, histograms (number of counts vs energy) must be obtained and compared with the simulation of the water's histogram. The difference in energy peaks between the water's histogram and the body materials are to be measured, thus, the difference among the energy peaks of these materials will be calculated to determine the sensibility that is needed to create gamma ray detectors in real life. [Preview Abstract] |
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L1.00018: Geant4 simulator for gamma collimator to obtain the requirements of a measuring device and to track them Selim Romero, Omar Hernandez, Jorge Lopez, Jason Holmes Our main focus is in a gamma source or proton interaction in general, because tracking gamma particles is too difficult, so we would like to ``measure'' gamma distributions-interaction to study how exactly interacts for certain geometries like a collimator to know how gammas interact with a collimator of lead, also trying to ``track'' gamma rays to give a branch or resolution to fix for at least this geometry and its set of variables, giving us the ability to make a device that could track or measure gammas as expected. After creating the gamma source, we'll measure and track gammas in the simulation, and based on that, we'll expect to force the track in a real detector/device, it is of most interest to optimize some parameters of the collimator like length, thickness and spacing, also study those variations versus the location-distance of the gamma source to find out a decent focal length. [Preview Abstract] |
(Author Not Attending)
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L1.00019: Effect of Gravity on Quasi-bound States of Antihydrogen. Nathan Floyd An initially unbounded positron within the electric field of an antiproton can be simulated to form quasi-bound states adiabatically. The effect of gravity on quasi-bound states of antihydrogen are simulated to show the changes of motion of the two particles. An analytical model is developed, and results appear to show that gravity may have an acute effect on correlated drift distances between the two particles. [Preview Abstract] |
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L1.00020: Creating a Wave-Powered Robot Christina Nissen, Alexandria Trevino, Ryan Benner In 2008 a 9.5-meter catamaran, the Suntory Mermaid II, traveled from Honolulu, Hawaii to Wakayama, Japan using two fins that converted wave energy into forward motion. Despite the success of this Wave Devouring Propulsion System (WDPS), little has been published about how it works. The goal of this project was to create a working model based on this method, and to analyze its performance. A wave-powered boat design would be ideal for a sensor platform that could travel over a wide area for an extended period without refueling. [Preview Abstract] |
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L1.00021: Applications of Silicon Photomultipliers, from Particle to Biomedical Physics Alejandro Ramirez, Xinran Li Silicon Photomultipliers are semiconducting devices that can operate at low voltages in low light situations with high sensitivity, and high gain without magnetic interference. They have the potential for high timing resolution, high signal to noise ratio and \textgreater 40{\%} Photon Detection Efficiency. While they have their flaws, these devices are becoming popular and are being used in today's experiments. DarkSide 20k is a planned underground dark matter detector that aims to detect Weakly Interacting Massive Particles (WIMPs) where SiPMs grouped onto a 50 X 50mm2 area will detect photons from WIMP interactions with liquid argon. However recent testing shows this SiPM configuration creates a 50pF/mm2 capacitance which adds noise to the readout. SiPMs are also being used with the planned 3D$\pi $ Detector. 3D$\pi $ is a full body Positron Emission Tomography scanner (PET) that uses the time of flight of annihilation photons to increase the resolution of PET imaging, reduce dosage inoculated to patients, and exposure time. A pair of simulations, one at Princeton and the other at the University of Houston, noted that we can achieve a timing resolution of 40ps. More results of these simulations will be presented. [Preview Abstract] |
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L1.00022: A Study of Efficiencies of Nano Molecules Used in Organic Solar Cells as Electron Acceptors Yun Jin Jeong, Richard Kyung Organic Solar Cells (OSCs) are the types of photovoltaic cells which produce electricity from sunlight by the photovoltaic effect. Conductive organic polymers are used for light absorption and to charge the cell. Research validating the potential use of the OSCs in the solar cell have led scientists to assess the safety of fullerene derivatives such as thermodynamical stability. Recently, computational and numerical simulation technology has been used as a means to determine the thermodynamic stability of such molecules. Scientists have modeled nano fullerene complexes, which are believed to be able to virtually attach large quantity of functional groups and donate electrons to polymers. The current research on organic solar cells has discovered that there are many advantages regarding the use of these solar cells. Organic, polymer-based solar cells, also commonly referred as OSCs, have been found to be a new and better alternatives to inorganic cells in several ways. Compared to silicon-based devices, the OSCs have many advantages such as light weightness, flexibility, semi-transparency, and lower manufacturing costs. This would make OSCs useful for cheap, large scale energy production. [Preview Abstract] |
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L1.00023: Two-photon flow cytometer with non-diffracting beams Andres Reyes, Yu Ding, Aurelio Paez, Chunqiang Li In vivo flow cytometry is used for medical diagnosis and the quantifying of circulating cells. This technique uses laser light for excitation to detect the fluorescent or acoustic signals after light is absorbed by molecules within the cell. A challenge in this approach is the limited detection depth due to the scattering of light by living tissue. Two-photon excitation based flow cytometers use infrared light and have longer detection depth, but limited sample volume. In this project a light-sheet microscope was made to increase the sample volume. In conventional flow cytometer Gaussian beams are commonly used, but it has limited sample volume as focused Gaussian beams diverge quickly after focus. So a self-healing and non-diffracting beam named Bessel beam is used to generate a light-sheet. Bessel beams have concentric rings that create background noise, but can be reduced through the use of two-photon excitation. This can be further improved by using Airy beams which have been shown to produce a three-fold increase in detection depth when compared to Bessel beams. In this study a scanning two-photon Airy beam light-sheet is implemented for greater resolution, sample size, and detection depth of microfluidic channels, therefore future in vivo flow cytometry. [Preview Abstract] |
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L1.00024: Pump-probe spectroscopic studies of surface plasmon resonance of gold nanorods Angela Angela, Yu Ding, Chunqiang Li Current optical microscopic techniques have widely utilized fluorescence of molecules to observe biomolecular and cellular processes in the nanosecond time scale. Femtosecond (10$^{\mathrm{-15\thinspace }}$s) laser spectroscopy allows us to study ultrafast dynamics in molecular systems. In this work, a pump-probe method which does not rely on the fluorescence of the material is being developed for super-resolved optical microscopy to study the surface plasmon resonance (SPR) of gold nanorods for future biomedical imaging. Two femtosecond pump laser beams at 510 nm, one with Gaussian mode and the other with donut mode, are modulated and used to pump the gold nanorods sample. A probe laser beam with Gaussian mode at 820nm detects the sample after excitation from pump beams, and subsequently becomes modulated due to SPR of gold nanorods. By observing the slight modulation of the probe beam we can study the ultrafast electron and phonon dynamics in gold nanorods [Preview Abstract] |
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L1.00025: Testing Fiber Tips for Use in Tip-Enhanced Raman Spectroscopy Brynna Neff, Khant Minn, Blake Birmingham, Zack Liege, Howard Lee, Zhenrong Zhang Tip-enhanced Raman spectroscopy (TERS) is a useful technique for chemical imaging of a sample. We aim to improve this technique by using optical fiber tips to perform TERS within a scanning tunneling microscope (STM). In this setup, the electromagnetic signal is carried along the fiber, eliminating the need for a complicated optical alignment. This project focused on producing fiber tips and testing their optical properties. To test the light collection of the fiber, we focused a supercontinuum laser onto a prism, and collected the light through a fiber approached to the back side of the prism where the laser was reflected. We found that as we changed the polarization of the incoming light, the relative intensities of the spectral peaks changed. We also tested the emission of light through the fiber by coupling the laser to the fiber core and taking optical images of the light emitted from the tip. We found that the light emission from the fiber is partially polarized along the tip axis. By putting various molecules on the fiber tip and measuring the reflected signal, we were able to get a strong Raman signal of CuPc. The optical properties of these fiber tips show the feasibility of the new scheme. [Preview Abstract] |
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L1.00026: Testing the suitability of a newly engineered smart substrate (VYO4: Er$+$3, Yb$+$3, @Nd$+$3 nanoparticles) for future remote temperature sensing experiments. Kassie Marble, Zachary Coker, Vladislav Yakovlev The progress of biomedical science depends on the availability of tools and instruments capable of analyzing biological systems in their natural environment without disturbing their behavior. Advanced optical characterization techniques, such as Raman spectroscopy, are powerful non-invasive and non-destructive means for obtaining the chemical properties of materials with applications in several fields including agriculture, chemistry, medicine, and materials science. By tailoring the properties of nanomaterials, a wide range of new biomedical applications including remote temperature sensing with existing chemical identification and imaging techniques has become available. I will present the design and outline of three separate optical systems that I helped to develop during this summer. This system tests the suitability of a smart substrate composed of a newly engineered temperature sensitive water-based biocompatible core/shell up-conversion nanoparticle (UCNP) for remote temperature sensing. Future applications of this optical imaging system will be discussed as well. [Preview Abstract] |
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L1.00027: Electrical Characterization of Thin Films Chandler Hutton, Ahad Talukder, Nick Talbert, Wilhelmus Geerts NiO samples are being investigated for possible application in Resistive RAM devices (RRAM). RRAM is non-volatile memory technology that is currently being considered to replace Flash memory beyond the 14 nm technology node. The material that is being studied are RF sputtered NiO$_{\mathrm{\thinspace }}$thin films made by reactive sputtering. We also measured resistivity of Al and Pt films and devices. The samples were characterized through four different methods; 2-point probe (2pp), linear 4-point probe (4pp), the Van der Pauw method (VDP) techniques, and by direct measurement on manufactured devices. We acquired measurements using a Keithley 2182A nanovoltmeter, a Keithley 6514 system electrometer, a Keithley 6221 DC and AC current source, and a Keithley 7001 switching system furnished with a Hall card all controlled by a labview program. Some samples were measured at both 298K and 77K by use of a cryostat. The resistivity parallel to the surface has semiconductor-like properties. Measurements were done as a function of the oxygen pressure during deposition. For 60 nm thickness, it was unveiled that the resistivity varied with the oxygen concentration in the sputter gas showing a maximum for 10 percent Oxygen and an average resistivity of 2.47E$+$6 ohms. [Preview Abstract] |
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L1.00028: Nanoscale Complexity in Room Temperature Ionic Liquid Mixtures: New Properties for Advanced Applications Carlos Cuellar, Jose Banuelos Room-temperature ionic liquid (RTIL) mixtures, as electrolytes in supercapacitors, have desirable properties including a good combination of wide thermal and electrochemical operation range, and high conductivity in comparison to conventional electrolytes. The nanostructural properties of mixtures of RTILs (e.g., BMIM$+$[TFSI]$-)$ with organic solvents (e.g., acetonitrile, dichloromethane, benzene, toluene, and tetrahydrofuran) are currently under investigation. The mass {\%} at which macroscopic phase separation is visible, in the BMIM$+$[TFSI]$-$/solvent mixtures, was determined by slowing increasing the solvent concentration. SAXS measurements at RTIL mass {\%} lower than the phase separation concentration were carried out to determine whether nanoheterogeneity is present leading up to macroscopic phase separation, and to characterize its structural properties. We find an increase in the scattering signal at low-Q compared to the expected scattering from a simple mixture of two liquids, suggesting long-range composition fluctuations. Studies of the dependence in temperature of this properties in the studied system is currently under investigation. Results and analysis of the length scales of the heterogeneity, and changes in intermolecular coordination in these systems will be discussed. [Preview Abstract] |
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L1.00029: Unravelling Defects in Hybrid Perovskite Solar Cell Structures Christian Saiz, Luis Martinez, Srinivasa Rao Singamaneni The hybrid organic-inorganic halogenoplumbate perovskites (MeNH$_{\mathrm{3}}$PbX$_{\mathrm{3}}$, where X is I and/or Br) have shown extraordinary photovoltaic properties with the record 22{\%} power conversion efficiency. The defects are known to cause unwanted hysteretic effects and device degradation. However, the usage of suitable defect-sensitive experimental techniques is necessary for their atomic level identification. In this work, we extensively employed electron spin resonance (ESR) spectroscopy at cryogenic temperatures to atomically identify the defects. For our study, we chose the inverted solar cell structure: PCBM/CH$_{\mathrm{3}}$NH$_{\mathrm{3}}$PbI$_{\mathrm{3}}$/PEDOT:PSS/Glass, where, the PCBM and PEDOT:PSS act as electron and hole transport layers. To accomplish this task, we prepared a series of samples as a function of ex-situ simulated solar irradiation up to 4 hours 30 minutes, including the sample which was not exposed to light. Controlled measurements were performed on moisturized, N$_{\mathrm{2}}$ gas, and UV-ozone treated samples to trace out the origin of ESR signals. [Preview Abstract] |
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L1.00030: Measuring M-dwarf Metallicity through Spectroscopy of Common Proper Motion Binaries at Optical Wavelengths Joshua Stenzel, Jennifer Marshall, Daniel Nagasawa, Luke Schmidt, Tristan Tipton, Ting Li M-dwarfs have a lifespan longer than the age of the Universe and therefore are useful in studying the formation of the Milky Way; understanding their metallicities provides a tracer of chemically older populations. We present a method for measuring M-dwarf metallicities by spectroscopy of F/G/K$+$M common proper motion binary pairs at optical wavelengths. We are in the process of determining an empirical relation between the molecular indices of the M-dwarf, such as CaH and TiO5, and the [Fe/H] metallicity of the Solar-like partner. We obtain high resolution spectroscopy of the F/G/K star for a detailed chemical abundance analysis, and low resolution spectroscopy of the M-dwarf to measure the molecular absorption features. Our analysis uses 50 binaries from the southern hemisphere over a broad range of metallicities and spectral types M0-M4. Future work includes applying this empirical relations to spectra obtained from the Sloan Digital Sky Survey (SDSS). [Preview Abstract] |
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L1.00031: From Catalysts to Elwenspoek Fuadi Rasyid Intends to compares of [e$^{\mathrm{2}}$/x] in \textbf{``Quantum Mechanics'' } to [$\chi^{\mathrm{2}}$/N ] from T. Mart {\&} A. Sulaksono at least the $\sigma $ (E ) $= \quad \pi $ r$_{\mathrm{0}}^{\mathrm{2}}$ [ 1 -- (V$_{\mathrm{BO}}$/E )] investigated implicitly to be similar with l $=$ L[1- (V$_{\mathrm{collapse}}^{\mathrm{2}}$ / V )] from Elwenspoek, \textit{et.al}- 1995. It come -- to extends the categorized as ``catalyst in decentralization'' use of COMPUTERS\textbf{ - }from Atsushi Arakaki, \textit{et.al } of ``Biomineralization-inspired..''/2015 of SiO$_{\mathrm{2}}$ of Fig. 1 of ``catalysts'' configurates similar curve of ``stamp-pinners'' with Newhouse {\&} Kopelman's ``fractal exciton fusion'' Fig 2's [log [(1/$\rho )$-(1/$\rho_{\mathrm{o}}$ )] $=$ [ log [ 1 -- ($\rho $/$\rho _{\mathrm{o\thinspace }})$] comprises 3 subtracted terms instead [1/c$^{\mathrm{2}}$]: [V$_{\mathrm{collapse}}^{\mathrm{2}}$ /V], [V$_{\mathrm{BO}}$/E] and [$\rho $/$\rho $o ] as well as [To /T1$_{\mathrm{\thinspace }}$]$^{\mathrm{2}}$ to comprehend ``mtDNA'' to ``chondritic meteors of Ka'aba {\&} Jesus shroud of \textless www.wikiwand.com/en/IPTN\textunderscore N-2130\textgreater [Preview Abstract] |
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