Physics Commons^™

Synthesis Of Boride-Titanium Coatings By Magnetron Sputtering Of Composite Targetss, A. S. Larionov, E. A. Zhakanbaeyev, A. L. Kozlovski, A. S. Dikov, S. B. Kislitsin, L. V. Chekushina

Eurasian Journal of Physics and Functional Materials

The paper presents the results of investigations of the structure and phase composition of titanium boride coatings deposited by magnetron sputtering from a target of a complex composition onto a steel substrate. The target for magnetron sputtering was obtained by sintering boron carbide and titanium powders. The structure and elemental composition of the coating were studied using X-ray diffractometry (XRD), scanning electron microscopy (SEM) and the energy-dispersive spectral (EDS). It was established that the coatin g structure is a mixture of Ti₂B₅ and TiB₁₂ phases with the total boron content of ≈ 80 at %, which …

Changing The Structure And Phasestates And The Microhardness Of The R6m5 Steel Surface Layer After Electrolytic-Plasma Nitriding, B. K. Rakhadilov, Sh. R. Kurbanbekov, M. K. Kilishkhanov, A. B. Kenesbekov, S. Amanzholov

Eurasian Journal of Physics and Functional Materials

The article examines the changes of the structural-phase states and the microhardness of the R6M5 steel surface layer after electrolytic-plasma nitriding. It is found that after electrolytic-plasma nitriding of the R6M5 steel surface, diffusion layer is formed, which is a nitrogen martensite. The phase composition of the diffusion layer varies depending on the nitriding temperature. An increase of R6M5 steel microhardness, depending on structural-phase state, is found out. The main factor, in fluencing the increase of microhardness of R6M5 high-speed steel with electrolytic-plasma nitriding, is the formation of nitro . gen martensite with monophasic nitride Fe₄N ( γ-phase), …

The Nature Of Luminescence Of Ki And Ki-Na Crystals At Low Temperature Deformation After Natural Decrease In The Symmetry Of The Lattice, K. Shunkeyev, N. Zhanturina, L. Myasnikova, D. Sergeyev, Z. Aimaganbetova, Sh. Sagimbaeva, A. Barmina, Zh. Ubaev

Eurasian Journal of Physics and Functional Materials

The X-ray luminescence spectra at low temperature (90K) uniaxial deformation were researched for KI and KI-Na crystals, that were stored for more than 10 years. The following regularities were observed: firstly, the intensities of the intrinsic emission bands at 3.3 eV (π) and 4.1 eV ( σ ) become equal in com- parison with freshly grown crystals; and secondly, with an increase in the degree of low-temperature uniaxial deformation, a gradual shift of the emission spectra occurs in two directions: the luminescence maximum at 3.3 eV shifts towards short wavelengths, the final position is fixed at 3.9 eV, which prac- …

A Brief Review Of Conductivity And Thermal Expansion Of Perovskite-Related Oxides For Sofc Cathode, A. V. Nikonov, K. A. Kuterbekov, K. Zh. Bekmyrza, N. B. Pavzderin

Eurasian Journal of Physics and Functional Materials

Cathode materials with mixed ion-electron conductivity (MIEC) are necessary for the development of low or intermediate temperature solid oxide fuel cells. Perovskite and perovskite-related materials are promising candidates on this role. In the review the conductivity and the thermal expansion of materials with various types of perovskite-related structures such as pure perovskite, double perovskite, brownmillerite and Ruddlesden-Popper phases have been compared. And the literature data on the values of the electronic and ionic conductivities, the oxygen diffusion coefficient, and the thermal expansion coefficient of various compositions have been collected. It was shown that the disordered cubic perovskites possess the higher …

Comparative Investigation Of Thermal And Structural Behavior In Renewably Sourced Composite Films Of Even-Even Nylons (610 And 1010) With Silk Fibroin, Kayla Calloway, Ye Xue, Vincent Altimari, Guoxiang Jiang, Xiao Hu

Faculty Scholarship for the College of Science & Mathematics

As the average life expectancy continues to increase, so does the need for resorbable materials designed to treat, augment, or replace components and functions of the body. Naturally occurring biopolymers such as silks are already attractive candidates due to natural abundance and high biocompatibility accompanied by physical properties which are easily modulated through blending with another polymer. In this paper, the authors report on the fabrication of biocomposite materials made from binary blends of Bombyx mori silk fibroin (SF) protein and renewably sourced low molecular weight nylon 610 and high molecular weight nylon 1010. Films were characterized using scanning electron …

Ultra-Low Temperature Properties Of Correlated Materials, Seyed Mohammad Ali Radmanesh

University of New Orleans Theses and Dissertations

Abstract

After the discovery of topological insulators (TIs), it has come to be widely recognized that topological states of matter can actually be widespread. In this sense, TIs have established a new paradigm about topological materials. Recent years have seen a surge of interest in topological semimetals, which embody two different ways of generalizing the effectively massless electrons to bulk materials. Dirac and, particularly, Weyl semimetals should support several transport and optical phenomena that are still being sought in experiments. A number of promising experimental results indicate superconductivity in members of half-Hesuler semimetals which realize the mixing singlet and triplet …

High Dynamic Range Optical Devices And Applications., Elijah Robert Jensen

Electronic Theses and Dissertations

Much of what we know about fundamental physical law and the universe derives from observations and measurements using optical methods. The passive use of the electromagnetic spectrum can be the best way of studying physical phenomenon in general with minimal disturbance of the system in the process. While for many applications ambient visible light is sufficient, light outside of the visible range may convey more information. The signals of interest are also often a small fraction of the background, and their changes occur on time scales so quickly that they are visually imperceptible. This thesis reports techniques and technologies developed …

59th Annual Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 59th annual meeting of the Rocky Mountain Conference on Magnetic Resonance, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Snowbird, Utah, July 22-27, 2018.

Dynamics And Structure Of Polyelectrolyte Complexes, Hamidreza Shojaei-Mahib

Doctoral Dissertations

Interaction of charged macromolecules among themselves and with charged interfaces in salty aqueous medium is a common phenomenon prevalent in biology and synthetic systems. We have addressed several inter-related issues in this general context. First we present a theory of adsorption of polyelectrolytes on the interior and exterior surfaces of a charged spherical vesicle. We derive the critical adsorption condition and the density profile of the polymer in terms of various characteristics of the polymer, vesicle, and the solution, such as the length and charge density of polymer, the radius and charge of the vesicle, the salt concentration of the …

Self-Assembling Networks In Soft Materials, Ishan Prasad

Doctoral Dissertations

This dissertation presents a study on heterogeneous network structure in two distinct classes of soft material systems: disordered assemblies of jammed binary spheres and ordered morphologies of block copolymer melts. The aim is to investigate the combined role of geometry and entropy in structure formation of soft matter assemblies. First, we investigate the influence of particle size asymmetry on structural properties of jammed binary sphere mixtures. We give evidence of two distinct classes of materials separated by a critical size ratio that marks the onset of a sharp transition due to simultaneous jamming of a sub-component of the packing. We …

The Effect Of Processing Conditions On The Energetic Diagram Of Cdte Thin Films Studied By Photoluminescence, Shamara P. Collins

USF Tampa Graduate Theses and Dissertations

The photovoltaic properties of CdTe-based thin films depend on recombination levels formed in the CdTe layer and at the heterojunction. The localized states are resultant of structural defects (metal sublattice, chalcogen sublattice, interstitial), controlled doping, deposition process, and/or post-deposition annealing. The photoluminescence study of CdTe thin films, from both the bulk and heterojunction, can reveal radiative states due to different defects or impurities. Identification of defects allows for potential explanation of their roles and influence on solar cell performance. A thorough understanding of the material properties responsible for solar cell performance is critical in further advancing the efficiency of devices. …

Molecular Assembly Of Monolayer-Protected Gold Nanoparticles And Their Chemical, Thermal, And Ultrasonic Stabilities, Steven Ray Isaacs

Masters Theses & Specialist Projects

Gold monolayer-protected nanoclusters (MPCs) with average diameters of 1-5 nm protected by alkane- and arenethiolates were synthesized. Mixed-monolayer protected nanoparticles (MMPCs) were prepared by functionalizing hexanethiolate-protected MPCs with either 11-mercaptoundecanoic acid (MUA-MMPC), 11-mercaptoundecanol (MUO-MMPC), or 4-aminothiophenol (ATP-MMPC) using ligand place exchange. Presentation of various chemical reagents such as nucleophile, acid, or base and change in physical environment through ultrasonic and thermal irradiation resulted in changes to particles and their physical properties. Thermogravimetric analysis (TGA) was used to measure maximum temperature of the derivated thermogravimetric peaks (Tmax,DTG) as a means of comparing temperature dependence of mass loss. The absorption spectrum within …

Energy Conversion System For Travelers (Ecost), Thipok Bovornratanaraks

The International Student Science Fair 2018

We have innovated “The Energy Conversion System for Travelers” or the ECoST. With the fact that most travelers have wheeled cabin-bags, whilst walking, the wheels will rotate so why don’t we harvest electricity from this kinetic energy? We thus install our innovation, the ECoST, to the bag to generate electricity from the spinning wheels. The electricity is then kept in the storage unit and ready to charge your empty battery devices in an emergency case via a USB port. To make life easy, our ECoST was designed to replicate the power bank charging method; therefore, we can charge …

Aftershocks In Slowly Compressed Bulk Metallic Glasses: Experiments And Theory, Louis W. Mcfaul, Wendelin Wright, Xiaojun Gu, Jonathan T. Uhl, Karin A. Dahmen

Faculty Journal Articles

We observe two distinct interevent time patterns in the slip avalanches of compressed bulk metallic glasses (BMGs). Small slip avalanches cluster together in time, but large slip avalanches recur roughly periodically. We compare the timing patterns of BMG slip avalanches with timing patterns of earthquakes and with the predictions of a mean-field model. The time clustering of small avalanches is similar to the known time clustering of earthquake foreshocks and aftershocks.

Imaging The Three-Dimensional Orientation And Rotational Mobility Of Fluorescent Emitters Using The Tri-Spot Point Spread Function, Oumeng Zhang, Jin Lu, Tianben Ding, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Fluorescence photons emitted by single molecules contain rich information regarding their rotational motions, but adapting single-molecule localization microscopy (SMLM) to measure their orientations and rotational mobilities with high precision remains a challenge. Inspired by dipole radiation patterns, we design and implement a Tri-spot point spread function (PSF) that simultaneously measures the three-dimensional orientation and the rotational mobility of dipole-like emitters across a large field of view. We show that the orientation measurements done using the Tri-spot PSF are sufficiently accurate to correct the anisotropy-based localization bias, from 30 nm to 7 nm, in SMLM. We further characterize the emission anisotropy …

Modeling Recombination In Solar Cells, Paul Chery

Macalester Journal of Physics and Astronomy

Solar cells are a competitive alternative to nonrenewable energy sources such as fossil fuels. However, the efficiency of these devices is limited by photogenerated carrier recombination. We use a finite difference numerical model to study recombination phenomena in the absorber layer of solar cells including alternate recombination models and the effects of spatial distribution of recombination centers. We compare the effect of using the constant lifetime approximation for recombination to the full Shockley-Read-Hall expression in Silicon solar cells and find that the constant lifetime approximation holds for high defect densities but not for high photon flux densities. Finally, we simulate …

Study Of Integral Characteristics Of The Turbulent Jet Elements Of Power Plants, M. S. Isatayev, Zh. K. Seydulla, A. Dosanova, Zh. Tolen

Eurasian Journal of Physics and Functional Materials

The work represents the results of experimental research of aerodynamics of three dimensional turbulent jets flowing from nozzles with rectangle outflow face. The results of measurements of average and pulse flow characteristics of threedimensional jets are given. The data on axis speed and turbulence intensity are given and an attempt to reveal their interrelation is made. The results of experimental data comparison on axis speed attenuation of three dimensional jets with the data for axis symmetric stream are presented.

Neutron Flux Distribution In (Pb,Ta And W) Target Using Accelerator Of 18 Mev Electron Beam, A. Didi, A. Dadoucha, O. Jai, M. Bencheikh

Eurasian Journal of Physics and Functional Materials

The production of neutrons can be carried out with the bombardment of the nuclei of heavy atoms, with accelerated and energetic particles (generally electrons). The electron collides with the target nuclei, so, 20 to 30 neutrons are produced by a process called "spallation". Several countries begin to develop neutron sources especially in the United States, Europe and Japan. The development of new measuring instruments and methods has generally increased the demand for neutron utilization in several areas, such as accelerator proton-based, where protons bombard a heavy metal target. The atoms of the target are excited, resulting in neutron emission.

Decreasing Of The Concentration Quenching Of Fluorescent Dye In A Solution By Introducing It To Nanoparticles Of Silicon Dioxide, V. G. Lukiaschenko, V. E. Messerle, A. B. Ustimenko, K. A. Umbetkaliev

Eurasian Journal of Physics and Functional Materials

The article presents the results of experimental studies of a double-chamber linear circuit DC electric arc plasmatron in experimental and industrial conditions. The electric arc plasmatron of the VORTEX-200 linear circuit with a rated power of 200 kW is designed for plasma ignition of a pulverized-coal torch, its stabilization and oil-free ignition of pulverized-coal boilers of thermal power plants.The linear circuit plasmatron contains two water-cooled casings isolated from each other, one of which has a hollow cylindrical electrode - a cathode having swirlers of the plasma-forming gas at both ends, and the other has an output electrode - an anode-diffuser …

Ecologically Safe Experimental Purpose Application Of Microwaves In The Treatment Of Chronic Neurological Disorders: Optimization And Risks, K. Arkhypova, A. Nosatov, M. Nurushev, P. Krasov, A. Fisun, A. Nurusheva

Eurasian Journal of Physics and Functional Materials

Current paper describes the experimental dual-purpose application of microwaves in a controlled clinical trial on optimizing therapy for chronic neurological disorders. As a part of integrated treatment, low-intensity microwave-assisted blood modification has been used. It represents a physiotherapeutic method based on the autologous blood transfusion (self-blood treatment) after the short-term exposure to microwaves ( lambda = 7.2 mm). Because of beneficial clinical impact of the microwave autohemotherapy previously observed, we aimed to find a possible way to track a manifestation of nonthermal microwave effects. For this purpose, we have applied a microwave single-frequency ( lambda = 7.6 mm) dielectrometry technique …

Investigation Of The Stability Of Nanostructures To Degradation, A. V. Petrov, I. E. Kenzhina, A. L. Kozlovskiy, K. K. Kadyrzhanov

Eurasian Journal of Physics and Functional Materials

The paper presents the dependence of the degradation degree in various aggressive media and time in a medium. The greatest deterioration in crystallographic characteristics of nanostructures in corrosive media is observed on the day 10th , which is due to partial destruction of the crystal structure as a result of oxidation processes. Also, an increase in the oxygen concentration in the structure leads to an increase in disorder regions, amorphization, and subsequent destruction of samples.

Development Of Electroforming Method For Coating Of Polymer Membranes By Graphene Oxide, F. R. Sultanov, Ch. Daulbayev, B. Bakbolat, Z. A. Mansurov

Eurasian Journal of Physics and Functional Materials

The current research is focused on development of electroforming method for coating of porous membranes by graphene oxide. A mixture based on polymethylmetacrylate dissolved in acetone and graphene oxide was pumped through the syringe pump onto the needle and high voltage was applied to both electrodes, one of which was on a glass plate, and the second was a needle thereby forming fibers, which coated the surface of membrane uniformly. The main parameters and concentrations of used polymer for uniform and complete coating of the surface of membrane are studied. Surface morphology of coated membranes was studied by SEM.

Decreasing Of The Concentration Quenching Of Fluorescent Dye In A Solution By Introducing It To Nanoparticles Of Silicon Dioxide, A. I. Mantel, A. E. Yensebayeva, S. B. Smatov, I. S. Irgibayeva

Eurasian Journal of Physics and Functional Materials

The technique of introduction a fluorescent dye Tris(bipyridine)ruthenium (II) chloride into nanoparticles of silicon dioxide in isopropyl alcohol was tested. The preparation of nanoparticles was carried out by means of the Stober method. The optimal reaction conditions were determined. It was found out that the penetration of a dye into silicon dioxide nanoparticles reduced the effect of concentration quenching of the dye and made it possible to achieve an increase in fluorescence intensity in the solution more than twofold. An attempt was made to functionalize the obtained particles by introducing amino groups onto the particle surface. Fused silver nanoparticles were …

Effect Of Omega(782) Resonance On The Response Functions For D(E,E'Π+)Nn Reaction, M. Tammam, Z. M. Mahmoud, M. S. Koubisy

Eurasian Journal of Physics and Functional Materials

In present work we study the effect of the Omega ( ω(782) ) resonance on the response functions for the incoherent positive pion electroproduction forms the deuteron at different values for the four-momentum transfers squared (Q² ) and the virtual photon lab energy ( k^lab₀ ). The study is carried out in the impulse approximation (IA) i.e. the final state interactions are neglected. The elementary amplitude for pion electroproduction is taken from the MAID-2007 model. The effect seems to be very small but almost increase with increasing the virtual photon lab energy.

Evaporation And Thermal Stresses In Molybdenum Irradiated By Electrons, G. Z. Ganeev, S. B. Kislitsin

Eurasian Journal of Physics and Functional Materials

Plasma disruption in the thermonuclear facility leads to a release of large energy flows to the chamber wall. The pulse duration is 10^-6 -10^-4 s, energy fluxes are of the order of 10⁸ - 10¹¹ Wm^-2 . High temperature of the protective coating surface causes its evaporation and, probably, destruction under the action of thermal stresses. A promising material for the first wall protection is, in particular, molybdenum. In order to check suitability of molybdenum as a protective coating, an experiment on irradiation of a molybdenum sample with electrons (parallelepiped - 2x10x0.3 mm) was carried …

Structural Studies To Determine The Mechanisms Supporting Multiferroic And Ferroelectric Properties Of Complex Oxides, Han Zhang

Dissertations

Multiferroics are a class of materials which possess both magnetic and electrical polarization with possible coupling between them. They show promise to enable new sensors and data storage devices with novel features, such as the possibility of writing polarization bits with magnetic fields at low power. The coexisting magnetic and ferroelectric order parameters are usually weakly coupled, preventing practical use. The development and study of new classes of materials with large magnetoelectric couplings is of high importance. Understanding the structure of these materials is key to this effort.

As one class of these systems, the RX3(BO₃)₄ has …

Investigation Of The Effects Of Harmful Radiation On Type-Ii Strained Layer Superlattice Focal Plane Arrays Operated In The Long Wave Infrared, Patrick Fumo

Electrical Engineering Theses and Dissertations

In-situ exposure of InAs/InAsSb strained layer superlattice focal plane arrays to gamma-rays revealed the possibility of a detector capable of imaging through a total ionizing dose event. Two long wave infrared focal plane arrays were exposed to a Co⁶⁰ source at dose rates of 60 Rads/s and 70 Rads/s in incremental steps up to a total accumulated dose of 30 kRads. The first device showed no degradation in dark current density with accumulated dose while the second device tested showed a small increase up to 1 kRad and minimal increases with subsequent dose steps. The primary imaging defect in …

Effects Of Tension On Resonant Frequencies Of Strings, Blake Burnett

Senior Theses

This project tests and explores resonance of strings. Since all materials and mechanisms are affected by vibrations, it is important to know the frequencies at which resonance occurs. To explore this subject, strings were used as a model material to test the effect tension has on resonance. The fundamental frequencies and the corresponding modes of resonance were used to analyze the data. The results of this experiment show that increasing tension on a string increases its resonance frequency. Understanding the physics behind resonance frequency allows systems to be designed to take advantage of resonance properties, or to avoid resonance where …

Thermoelectrics And Thermoelectric Devices, Benjamin T. Erck

Senior Theses

The field of thermoelectrics has many applications, and more are found in everyday systems. From its current studies, it is apparent that improving the figure of merit zT (which defines a good thermoelectric material) is important in the effectiveness of power generation. Another important part of thermoelectrics is the duality of these devices. They can both move heat and generate power, depending on their role in the system. In this thesis research, a process was made to test these thermoelectric relationships for a few Peltier devices in order to understand their efficiencies and what systems they can be applied to.

Measuring The Double Layer Capacitance Of Electrolyte Solutions Using A Graphene Field Effect Transistor, Agatha Ulibarri

Senior Theses

When operating graphene field effect transistors (GFETs) in fluid, a double layer capacitance (C_dl) is formed at the surface. In the literature, the C_dl is estimated using values obtained using metal electrode experiments. Due to the distinctive electronic and surface properties of graphene, there is reason to believe these estimates are inadequate. This work seeks to directly characterize the double layer capacitance of a GFET. A unique method for determining the C_dl has been implemented, and data has been obtained for three electrolytes and one ionic fluid. The results yield dramatically lower C_dl values than …