Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- BRC (5)
- Barium compounds (1)
- Biology (1)
- Calcium compounds (1)
- Chalcogenides (1)
-
- Cytokine (1)
- Dielectric polarisation (1)
- Electrical Engineering (1)
- Electrostatics (1)
- Ferroelectric materials (1)
- Ferroelectric transitions (1)
- Ferromagnetism (1)
- Force (1)
- Immunity (1)
- Magnetic force microscopy (1)
- Monocytes (1)
- Nanoparticle (1)
- Nanotoxicity (1)
- Phonons (1)
- Physics education (1)
- Pulsed laser deposition (1)
- Raman scattering (1)
- Raman spectra (1)
- Raman spectroscopy (1)
- Semiconductors (1)
- Student experiments (1)
- T lymphocyte (1)
- ZnO (1)
Articles 1 - 9 of 9
Full-Text Articles in Physics
A High-Yield Synthesis Of Chalcopyrite Cuins2 Nanoparticles With Exceptional Size Control, Aaron Thurber, Alex Punnoose
A High-Yield Synthesis Of Chalcopyrite Cuins2 Nanoparticles With Exceptional Size Control, Aaron Thurber, Alex Punnoose
Physics Faculty Publications and Presentations
We report high-yield and efficient size-controlled syntheses of Chalcopyrite CuInS2 nanoparticles by decomposing molecular single source precursors (SSPs) via microwave irradiation in the presence of 1,2-ethanedithiol at reaction temperatures as low as 100◦C and times as short as 30 minutes. The nanoparticles sizes were 1.8nm to 10.8 nm as reaction temperatures were varied from 100◦C to 200◦C with the bandgaps from 2.71 eV to 1.28 eV with good size control and high yields (64%–95%). The resulting nanoparticles were analyzed by XRD, UV-Vis, ICP-OES, XPS, SEM, EDS, and HRTEM. Titration studies by 1H NMR using SSP 1 with 1,2-ethanedithiol …
A 236-Ghz Fe3+ Epr Study Of Nanoparticles Of The Ferromagnetic Room-Temperature Semiconductor Sn1-XFeXO2 (X = 0.005), Sushil K. Misra, S. I. Andronenko, Alex Punnoose, Dmitry Tipikin, J. H. Freed
A 236-Ghz Fe3+ Epr Study Of Nanoparticles Of The Ferromagnetic Room-Temperature Semiconductor Sn1-XFeXO2 (X = 0.005), Sushil K. Misra, S. I. Andronenko, Alex Punnoose, Dmitry Tipikin, J. H. Freed
Physics Faculty Publications and Presentations
High-frequency (236 GHz) electron paramagnetic resonance (EPR) studies of Fe3+ ions at 255 K are reported in a Sn1-xFexO2 powder with x = 0.005, which is a ferromagnetic semiconductor at room temperature. The observed EPR spectrum can be simulated reasonably well as the overlap of spectra due to four magnetically inequivalent high-spin (HS) Fe3+ ions (S = 5/2). The spectrum intensity is calculated, using the overlap I(BL) + (I(HS1) + I(HS2) + I(HS3) + I(HS4)) 9 x e-0.00001xB, where B is the magnetic field intensity …
Transition From N-Type To P-Type Destroys Ferromagnetism In Semiconducting Sn1-XCoXO2 And Sn1-XCrXO2 Nanoparticles, C. Van Komen, A. Punnoose, M. S. Seehra
Transition From N-Type To P-Type Destroys Ferromagnetism In Semiconducting Sn1-XCoXO2 And Sn1-XCrXO2 Nanoparticles, C. Van Komen, A. Punnoose, M. S. Seehra
Physics Faculty Publications and Presentations
This work reports strong correlations between the structural, magnetic and electronic properties of room temperature ferromagnets (RTFM) Sn1-xCoxO2 and Sn1-xCrxO2 for x = 0 to 0.1. The samples prepared by the sol-gel chemical method show RTFM for x < xL with the limiting concentration xL = 0.01 for Co doping and xL = 0.025 for Cr doping. As doping level x is increased from x = 0, the magnetic moment per ion, μ, increases and the lattice volume VL decreases up to x = xL. …
Structural Development In Ge-Rich Ge-S Glasses, Y. Sakaguchi, Dmitri Tenne, Maria Mitkova
Structural Development In Ge-Rich Ge-S Glasses, Y. Sakaguchi, Dmitri Tenne, Maria Mitkova
Physics Faculty Publications and Presentations
The Raman spectra of Ge-S glasses in the Ge-rich region from Ge 33 to 46 % have been investigated in order to know the structural development of the network glasses. From the detailed curve fits, we have found that there is an unassigned peak at 410 cm-1 and it becomes larger with increasing Ge composition. To clarify the structural origin of the peak, we virtually constructed the atomic arrangement of the glassy state starting from the crystalline state through the liquid state and changed the composition gradually depleting the medium in sulfur. From the consideration of the structural modeling …
The Influences Of Cell Type And Zno Nanoparticle Size On Immune Cell Cytotoxicity And Cytokine Induction, Cory Hanley, Aaron Thurber, Charles Hanna, Alex Punnoose, Jianhui Zhang, Denise G. Wingett
The Influences Of Cell Type And Zno Nanoparticle Size On Immune Cell Cytotoxicity And Cytokine Induction, Cory Hanley, Aaron Thurber, Charles Hanna, Alex Punnoose, Jianhui Zhang, Denise G. Wingett
Physics Faculty Publications and Presentations
Nanotechnology represents a new and enabling platform that promises to provide a range of innovative technologies for biological applications. ZnO nanoparticles of controlled size were synthesized, and their cytotoxicity towards different human immune cells evaluated. A differential cytotoxic response between human immune cell subsets was observed, with lymphocytes being the most resistant and monocytes being the most susceptible to ZnO nanoparticle-induced toxicity. Significant differences were also observed between previously activated memory lymphocytes and naive lymphocytes, indicating a relationship between cell-cycle potential and nanoparticle susceptibility. Mechanisms of toxicity involve the generation of reactive oxygen species, with monocytes displaying the highest levels, …
Conceptual Development About Motion And Force In Elementary And Middle School Students, Dewey I. Dykstra, Dale R. Sweet
Conceptual Development About Motion And Force In Elementary And Middle School Students, Dewey I. Dykstra, Dale R. Sweet
Physics Faculty Publications and Presentations
Methods of physics education research were applied to find what kinds of changes in 4th, 6th, and 8th grade student understanding of motion can occur and at what age. Such findings are necessary for the physics community to effectively discharge its role in advising and assisting pre-college physics education. Prior to and after instruction the students were asked to carefully describe several demonstrated accelerated motions. Most pre-instruction descriptions were of the direction of motion only. After instruction, many more of the students gave descriptions of the motion as continuously changing. Student responses to the diagnostic and to the activity materials …
Ferroelectric Phase Transitions In Three-Component Short-Period Superlattices Studied By Ultraviolet Raman Spectroscopy, Dmitri Tenne, H. N. Lee, R. S. Katiyar, X. X. Xi
Ferroelectric Phase Transitions In Three-Component Short-Period Superlattices Studied By Ultraviolet Raman Spectroscopy, Dmitri Tenne, H. N. Lee, R. S. Katiyar, X. X. Xi
Physics Faculty Publications and Presentations
Vibrational spectra of three-component BaTiO3SrTiO3CaTiO3 short-period superlattices grown by pulsed laser deposition with atomic-layer control have been investigated by ultraviolet Raman spectroscopy. Monitoring the intensity of the first-order phonon peaks in Raman spectra as a function of temperature allowed determination of the ferroelectric phase transition temperature, Tc. Raman spectra indicate that all superlattices remain in the tetragonal ferroelectric phase with out-of-plane polarization in the entire temperature range below Tc. The dependence of Tc on the relative thicknesses of ferroelectric (BaTiO3) to non-ferroelectric materials (SrTiO3 and CaTiO3 …
Separation Of Topographic Features From Magnetic Force Images Using Capacitive Coupling Effect, Byung I. Kim
Separation Of Topographic Features From Magnetic Force Images Using Capacitive Coupling Effect, Byung I. Kim
Physics Faculty Publications and Presentations
Separation of topographic features from magnetic images has been an issue for the past two decades in magnetic force microscopy (MFM). The frequent pickups of the topographic features are interpreted as transitions of the tip between bistable states of the tip-sample assembly in the noncontact and tapping regions. MFM using electrostatic force modulation demonstrates the separation of the topographic features from the magnetic images by removing the tapping state from the bistable states through the introduction of a capacitive coupling.
Ferroelectricity In Ultrathin Strained Batio3 Films: Probing The Size Effect By Ultraviolet Raman Spectroscopy, Dmitri Tenne, P. Turner, J. D. Schmidt, M. Biegalski, Y. L. Li, L. Q. Chen, A. Soukiassian
Ferroelectricity In Ultrathin Strained Batio3 Films: Probing The Size Effect By Ultraviolet Raman Spectroscopy, Dmitri Tenne, P. Turner, J. D. Schmidt, M. Biegalski, Y. L. Li, L. Q. Chen, A. Soukiassian
Physics Faculty Publications and Presentations
We demonstrate a dramatic effect of film thickness on the ferroelectric phase transition temperature, Tc, in strained BaTiO3 films grown on SrTiO3 substrates. Using variable temperature ultraviolet Raman spectroscopy enables measuring Tc in films as thin as 1.6 nm, and film thickness variation from 1.6 to 10 nm leads to Tc tuning from 70 to about 925K. Raman data are consistent with synchrotron x-ray scattering results, which indicate the presence of of 180◦ domains below Tc, and thermodynamic phase-field model calculations of Tc as a function of thickness.