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Biological and Chemical Physics Commons™
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- High pressure (Science) (3)
- Amorphous glucose (1)
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Articles 1 - 10 of 10
Full-Text Articles in Biological and Chemical Physics
High Pressure Structural Studies On Nb5si3 Up To 26.2 Gpa, Brandon Stewart, Ravhi S. Kumar
High Pressure Structural Studies On Nb5si3 Up To 26.2 Gpa, Brandon Stewart, Ravhi S. Kumar
Undergraduate Research Opportunities Program (UROP)
With the use of synchrotron techniques, we can better understand how crystalline structures behave under extreme conditions. This yields the opportunity to resolve complex crystal structures [1]. Here, we focus on the high pressure crystal structure of Nb5Si3. Refractory metal silicides are an important class of materials as they are used in high temperature applications such as turbines and aerospace modules. As an example, the performance of a jet engine is highly influenced by the maximum internal pressure and temperature possible. Obtaining higher levels of thrust is dependent upon the material's ability to remain structurally sound under extreme temperatures and …
Crystal Structural Behavior Of Cocu₂O₃ At High Temperatures, April Jeffries, Ravhi S. Kumar, Andrew L. Cornelius
Crystal Structural Behavior Of Cocu₂O₃ At High Temperatures, April Jeffries, Ravhi S. Kumar, Andrew L. Cornelius
Undergraduate Research Opportunities Program (UROP)
High temperature structure of CoCu₂O₃ The spin ladder compounds have received much attention recently due to their relation to the high transition temperature superconductivity. Also the study of spin ladder compounds is of great interest to explore the specific characteristics that result in their behavior. The CoCu₂O₃ spin ladder crystal structure is similar to SrCu₂O₃, which is apparent composition for many high temperature superconductors. The effects of temperature on structural change are investigated for this system. High temperature x-ray diffraction patterns were collected up to 1000⁰C and the variation of lattice parameters as a function of temperature up to decomposition …
Structural And Magnetic Properties Of Iron Clusters, Andrew Mohrland, Eunja Kim
Structural And Magnetic Properties Of Iron Clusters, Andrew Mohrland, Eunja Kim
Undergraduate Research Opportunities Program (UROP)
Electronic, magnetic, and chemical properties of Fe nanoparticles are of particular interest for materials science, engineering, and metallurgical applications, including biomedical applications (e.g., medical imaging, cancer treatment, etc.). In this study, we search for the most stable geometries of the Fe clusters, Fen, up to n=8. Binding energies, magnetic moments, bond lengths, bond angles, and charge densities of clusters are computed and compared to the available experimental data. The various cluster isomers were examined energetically. We found that, in general, higher dimensional geometries are more stable than lower dimensions (i.e., 1-dimension or 2-dimension). Calculations for the Fe dimer yield a …
Laser Microraman Study Of Reduced Synthesized Spinel Powders, Alexandra J. Leandre, Michael M. Rodriguez, Joseph Lussier, Brittany Morgan, Brian Hosterman, John W. Farley
Laser Microraman Study Of Reduced Synthesized Spinel Powders, Alexandra J. Leandre, Michael M. Rodriguez, Joseph Lussier, Brittany Morgan, Brian Hosterman, John W. Farley
Undergraduate Research Opportunities Program (UROP)
The Raman effect is the excitation or de-excitation of vibrational modes resulting from the inelastic scattering of light from a gas, liquid, or solid with a shift in energy from that of the usually incident radiation. Raman microscopy was performed on synthesized spinel powders of solid solution FexCr3-xO4 to determine the dependence of the vibrational modes upon the metal cations. The powders were synthesized in a combustion reaction using metal nitrates and urea. The oxide powders were reduced in a hydrogen/argon gas flow at high temperature.
Potassium Chlorate Decomposition Under High Pressure, Harrison Ruiz, Michael G. Pravica, Martin Galley
Potassium Chlorate Decomposition Under High Pressure, Harrison Ruiz, Michael G. Pravica, Martin Galley
Undergraduate Research Opportunities Program (UROP)
High pressure physics involves placing various substances under high pressure and observing changes in that substance. In this experiment this high amount of pressure is induced using a diamond anvil cell. A diamond anvil cell uses a metal gasket to hold the sample between two diamonds, which will press on the sample to reach high pressures. High pressures are reached with a moderate amount of force by exerting that force over a small area. Diamonds are used for the compression because of their hardness and ability to resist compression. The pressure being exerted on the sample using a diamond anvil …
High Pressure X-Ray Diffraction Studies On Zrfe2: A Potential Hydrogen Absorption Medium, Dylan D. Wood, Ravhi S. Kumar
High Pressure X-Ray Diffraction Studies On Zrfe2: A Potential Hydrogen Absorption Medium, Dylan D. Wood, Ravhi S. Kumar
Undergraduate Research Opportunities Program (UROP)
The potential application of intermetallic compounds (IMC) under high hydrogen pressure in studies of hydrogen sorption properties is defined by two important properties. Intermetallics of Laves phases have a suitable binding energy for hydrogen which allows its absorption or desorption near room temperature and atmospheric pressure. High pressures allow to efficiently interact hydrogen with intermetallics, which were considered nonhydride forming [1,2]. For example, ZrFe2, ZrCo2, and ZrFe2 possess fairly high hydrogen absorption capacity at high pressures [3]. A nonactivated ZrFe2 sample starts to interact with hydrogen only at 80 MPa, while equilibrium absorption and desorption pressures of the activated alloy …
High Pressure Structural Studies On Eus Nano Particles Up To 52 Gpa, Kristie Canaday, Ravhi S. Kumar
High Pressure Structural Studies On Eus Nano Particles Up To 52 Gpa, Kristie Canaday, Ravhi S. Kumar
Undergraduate Research Opportunities Program (UROP)
Crystal size reduction in bulk materials changes the structural and magnetic properties considerably [1]. More importantly the transition pressure is strongly influenced by temperature, pressure, and the crystallite size effect. Rare earth europium chalcogenides crystallize in the NaCl (rock salt) type structure. The interest in Eu nanomaterials is motivated by the possibility of their use in magnetic devices [2,3]. Recent studies suggest that europium chalcogenide nanocrystals exhibit significant changes in their structural and magnetic properties, compared to bulk chalcogenides, when the nanocrystal diameter decreases. The crystal structure and phase transition behavior of EuS nanoparticles have been investigated and compared as …
High Pressure Studies Of Titanium Hydride Up To 50 Gpa With Synchrotron X-Ray Diffraction, Greg Harding, Patricia Kalita, Stanislav Sinogeikin, Andrew Cornelius
High Pressure Studies Of Titanium Hydride Up To 50 Gpa With Synchrotron X-Ray Diffraction, Greg Harding, Patricia Kalita, Stanislav Sinogeikin, Andrew Cornelius
Undergraduate Research Opportunities Program (UROP)
Titanium dihydride has the potential to play an important role in the efficiency of high density hydrogen storage. The structural instability of TiH2 at high pressures makes an accurate characterization of its structure a vital part of understanding its behavior. A sample of TiH2 was placed in a diamond anvil cell and studied from ambient pressure up to 53 GPa using in situ synchrotron x-ray diffraction at the Advanced Photon Source (APS) of Argonne National Laboratory (Sector 16, HPCAT). From data of the evolution of the structure with pressure, an equation of state was obtained to model the behavior of …
High Pressure Infrared Studies Of Hmx, Jennifer Wojno, Michael G. Pravica, Martin Galley
High Pressure Infrared Studies Of Hmx, Jennifer Wojno, Michael G. Pravica, Martin Galley
Undergraduate Research Opportunities Program (UROP)
We are studying the effects of pressure on HMX (Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) using infrared spectroscopy. The sample is put under pressure using a diamond anvil cell at ambient temperature, data is collected at the National Synchrotron Light Source in Brookhaven National Laboratory. In analyzing this data, we hope to learn more about the molecular vibrations as the molecule bends and deforms under pressure. Such understanding could aid in determining new safety standards or more efficient ways of using HMX. In future studies, we intend to include the aspect of temperature variation in addition to pressure, with the goal of describing the molecule …
The Search For Ferroelectric Domain Structures In Carbohydrate Glasses Using Atomic Force Microscopy, Louis S. Prahl, David P. Shelton
The Search For Ferroelectric Domain Structures In Carbohydrate Glasses Using Atomic Force Microscopy, Louis S. Prahl, David P. Shelton
Undergraduate Research Opportunities Program (UROP)
D-glucose was studied as a possible candidate for ferroelectric domain imaging using an Atomic Force Microscope (AFM). The large dipole moment of carbohydrates is such that they may show localized ferroelectric domain formation in liquid phase. Samples were heated at their melting point on glass slides and then left to cool to room temperature in a desiccator. Differential Thermal Analysis (DTA) was used to test the effectiveness of this method, and it was found that the oven preparation created samples with 41% crystallinity, where both a glass transition and sharp melting peak were observed. DTA was again used to find …