Investigations Into Structure And Properties Of Atomically-Precise Transition Metal-Chalcogenide Clusters Of Crte And Ligated Cr6te8(Pet3)6,
2017
Virginia Commonwealth University
Investigations Into Structure And Properties Of Atomically-Precise Transition Metal-Chalcogenide Clusters Of Crte And Ligated Cr6te8(Pet3)6, Anthony F. Pedicini
Theses and Dissertations
The complete understanding of a clusters electronic structure, the primary mechanisms for its properties and stabilization is necessary in order to functionalize them for use as building blocks within novel materials. First principle theoretical studies have been carried out upon the electronic properties of CrxTey (x = 1 – 6, y = 0 – 8, x + y ≤ 14), as well as for the larger triethylphosphine (PEt3) ligated cluster system of Cr6Te8(PEt3)6. Together, we aim to use the information garnered from the smaller clusters to address …
Preparation And Evaluation Techniques Of Porous Materials And Mixed Matrix Membranes For Targeted Co2 Separation Applications,
2017
Virginia Commonwealth University
Preparation And Evaluation Techniques Of Porous Materials And Mixed Matrix Membranes For Targeted Co2 Separation Applications, Tsemre Tessema
Theses and Dissertations
The use of porous sorbents for physisorptive capture of CO2 from gas mixtures has been deemed attractive due to the low energy penalty associated with recycling of such materials. Porous organic polymers (POPs) have emerged as promising candidates with potential in the treatment of pre- and post- fuel combustion processes to separate CO2 from gas mixtures. Concurrently, significant advances have been made in establishing calculation methods that evaluate the practicality of porous sorbents for targeted gas separation applications. However, these methods rely on single gas adsorption isotherms without accounting for the dynamic gas mixtures encountered in real-life applications. …
Reply To ‘On The Bonding In Ligand-Protected Gold Clusters’,
2017
Shanghai Institute of Applied Physics
Reply To ‘On The Bonding In Ligand-Protected Gold Clusters’, Wen Wu Xu, Xiao Cheng Zeng, Yi Gao
Xiao Cheng Zeng Publications
In the recent Correspondence, Professor Henrik Grönbeck made several comments on the recently developed grand unified model (GUM), in particular using the ligand-protected gold cluster [Au25(SR)18]1− as an example. We noted that the latter cluster can be viewed as belonging to a special group of ligand-protected gold clusters that contain one or several icosahedral Au13 motifs. For this group of clusters, a secondary block Au13(8e) has been identified as a more convenient way to describe their structure anatomy and evolution. Another extension of the GUM is the identification of the new elementary …
Manifestations Of Classical Physics In The Quantum Evolution Of Correlated Spin States In Pulsed Nmr Experiments,
2017
Bucknell University
Manifestations Of Classical Physics In The Quantum Evolution Of Correlated Spin States In Pulsed Nmr Experiments, Martin K. Ligare
Faculty Journal Articles
Multiple-pulse NMR experiments are a powerful tool for the investigation of mole- cules with coupled nuclear spins. The product operator formalism provides a way to understand the quantum evolution of an ensemble of weakly coupled spins in such experiments using some of the more intuitive concepts of classical physics and semi- classical vector representations. In this paper I present a new way in which to inter- pret the quantum evolution of an ensemble of spins. I recast the quantum problem in terms of mixtures of pure states of two spins whose expectation values evolve identi- cally to those of classical …
Size And Shape Control In Metal Nanoparticles And Nanocomposites,
2017
Wilfrid Laurier University
Size And Shape Control In Metal Nanoparticles And Nanocomposites, Tomendro Subedi
Theses and Dissertations (Comprehensive)
This thesis describes major findings on the shape transformation of the precursor silver decahedral nanoparticles (AgDeNPs) with pentagonal symmetry and twin defects into silver pentagonal prism nanoparticles (AgPPNPs) using Br¯ as a shape selective reagent. Silica-encapsulation of the gold-plated AgDeNPs was also carried out forming ordered arrays of silica encapsulated gold-plated AgDeNPs (SiO2@Au@AgDeNPs) of different sizes. At first, synthetic procedures for AgDeNPs (pentagonal bipyramids), silver pentagonal rod nanoparticles (AgPRNPs) and gold-plating of AgDeNPs (Au@AgDeNPs) were optimized. Gold plating enhances the chemical stability of AgDeNPs and preserves the superior plasmonic properties of silver. This thesis deals with the transformation …
A Density Functional Theory Study Of Intrinsically Chiral Semiconductor Nanocrystals,
2017
Wilfrid Laurier University
A Density Functional Theory Study Of Intrinsically Chiral Semiconductor Nanocrystals, Richard Edwards
Theses and Dissertations (Comprehensive)
A plethora of work has been done in the area of nanoparticles of late due to the fact that chemists (and physicists) have discovered that the properties of nanoparticles differ from both those of the bulk material and the atoms themselves. Nanoparticles have become of high interest for the use as catalysts while materials like graphene, being only one atom thick, have been shown to be great electrical conductors in comparison with the 3D structure of diamond. Among these peculiar nanoscale properties is the phenomenon of nanochirality, where a nanoparticle can exhibit chirality that does not extend to the macroscale …
Charge Transport In Electronic-Ionic Composites,
2017
University of Kentucky
Charge Transport In Electronic-Ionic Composites, Long Zhang
Theses and Dissertations--Chemical and Materials Engineering
The goal of this thesis is to generate fundamental understandings of charge transport behaviors of composites consisting of garnet structured Al substituted Li7La3Zr2O12 (LLZO) electrolyte and LiCoO2 electrode. In order to take full advantage of all-solid-state batteries, bulk type composite electrodes should be introduced to increase energy and power density. However, the charge utilization of bulk type composite electrodes is quite low. Understanding ionic conduction behavior is, therefore, important for improving the performance of all-solid-state batteries, because ion conduction within solids depends on effective pathways. Electronic conductivity can be easily compensated by …
Using Low-Coherence Interferometry To Monitor Cell Invasion In An In-Vitro Model System,
2017
University of Central Florida
Using Low-Coherence Interferometry To Monitor Cell Invasion In An In-Vitro Model System, Behnaz Davoudi Nasab
Honors Undergraduate Theses
In an optically random system, such as naturally occurring and man-made media, light undergoes pronounced multiple scattering. This phenomenon has shown a remarkable potential in characterizing complex materials. In this regime, scattering occurs from each individual center of the scattering and independent scattering events lead to multiple light scattering. This phenomenon is often described as a random walk of photons and can be modeled in terms of a diffusion equation based on the radiative transfer theory. In this thesis, we used optical path-length spectroscopy (OPS), which is an experimental method to obtain the path-length probability density of the propagating light …
Semiconductor Photocatalysis: Mechanisms, Photocatalytic Performances And Lifetime Of Redox Carriers,
2017
University of Kentucky
Semiconductor Photocatalysis: Mechanisms, Photocatalytic Performances And Lifetime Of Redox Carriers, Ruixin Zhou
Theses and Dissertations--Chemistry
Photocatalytic reactions mediated by semiconductors such as ZnS, TiO2, ZnO, etc. can harvest solar energy into chemical bonds, a process with important prebiotic and environmental chemistry applications. The recycling of CO2 into organic molecules (e.g., formate, methane, and methanol) facilitated by irradiated semiconductors such as colloidal ZnS nanoparticles has been demonstrated. ZnS can also drive prebiotic reactions from the reductive tricarboxylic acid (rTCA) cycle such as the reduction of fumarate to succinate. However, the mechanism of photoreduction by ZnS of the previous reaction has not been understood. Thus, this thesis reports the mechanisms for heterogeneous photocatalytic reductions …
Attosecond Spectroscopy Probing Electron Correlation Dynamics,
2017
Wayne State University
Attosecond Spectroscopy Probing Electron Correlation Dynamics, Alexander Heinecke Winney
Wayne State University Dissertations
Electrons are the driving force behind every chemical reaction. The exchange, ionization, or even relaxation of electrons is behind every bond broken or formed. According to the Bohr model of the atom, it takes an electron 150 as to orbit a proton[6]. With this as a unit time scale for an electron, it is clear that a pulse duration of several femtoseconds will not be sufficient to understanding electron dynamics. Our work demonstrates both technical and scientific achievements that push the boundaries of attosecond dynamics. TDSE studies show that amplification the yield of high harmonic generation (HHG) may be possible …
Bond Length And Bond Valence For Tungsten-Oxygen And Tungsten-Sulfur Bonds,
2017
Arkansas Tech University
Bond Length And Bond Valence For Tungsten-Oxygen And Tungsten-Sulfur Bonds, F. D. Hardcastle, R. Lykins
Journal of the Arkansas Academy of Science
In 1947, Linus Pauling presented an “empirical” dependence of bond valence (s, also referred to as bond order) and bond length R: s = exp[(R0-R)/b], where R0 is bond length of unit valence and “b” is a fitting parameter. Recently, an expression was derived for relating the b fitting parameter to theoretically derived atomic orbital exponents. With a method to calculate b, both R0 and atomic orbital exponents can be experimentally determined through optimized fitting for W-O and W-S bonds. In the present study, bond …
Bond Length And Bond Valence Relationships For Chromium Oxides, Chromium Sulfides, Molybdenum Oxides, And Molybdenum Sulfides,
2017
Arkansas Tech University
Bond Length And Bond Valence Relationships For Chromium Oxides, Chromium Sulfides, Molybdenum Oxides, And Molybdenum Sulfides, J. Labrecque, F. D. Hardcastle
Journal of the Arkansas Academy of Science
Pauling determined an empirical logarithmic dependence of bond order (bond valence), s, to bond length, R, s = exp(R0 – R/ b), where R0 is unit bond length and b is a fitting parameter. Recently, an expression was derived for relating the b fitting parameter to theoretically derived atomic orbital exponents. With a method to calculate b, both R0 and atomic orbital exponents can be experimentally determined through optimized fitting for Cr-O, Cr-S, Mo-O, and Mo-S. In the present study, bond length – valence relationships are found for Cr-O, Cr-S, Mo-O, and Mo-S chemical …
Design And Activation Of Frequency Tunable 200ghz Gyrotron,
2017
Washington University in St. Louis
Design And Activation Of Frequency Tunable 200ghz Gyrotron, Natalie Golota, Faith Scott, Edward Saliba, Brice Albert, Alexander Barnes
Undergraduate Research Symposium Posters
Dynamic Nuclear Polarization (DNP) when combined with Nuclear Magnetic Resonance (NMR) yields high sensitivity spectra while decreasing sample acquisition time. DNP transfers polarization from electron to nuclear spins, giving a strong enhancement of NMR signal. DNP is rapidly developing area of research due in part to application of cyclotron resonance masers (gyrotron) as high power microwave sources. Gyrotrons provide a high-power, high-frequency microwave source that can be used in close proximity to high field NMR magnets. Gyrotrons are operated under strong vacuum and within a cryogenic superconducting magnetic. Gyrotron microwave power is generated by a magnetron injection gun (MIG) composed …
Choline Chloride Eutectics: Low Temperature Applications,
2017
South Dakota State University
Choline Chloride Eutectics: Low Temperature Applications, Kaila M. Kuehn, Camille M. Massmann, Natalie R. Sovell
The Journal of Undergraduate Research
Deep eutectic solvents (DESs) have a lower melting point than each of their individual components due to ion dipole interactions or hydrogen bonding. Traditionally, DES are used for processing metals through plating and have many synthesis applications. DES are able to be substituted for hazardous solvents that are traditionally used for metal plating and synthesis. This, along with many other advantageous properties, appear promising for the use of DESs as solvents or for use in electrochemical systems, particularly at low temperatures. Choline chloride:propylene glycol was a novel DES synthesized and analyzed for its properties, including melting point, viscosity, conductivity, heat …
A Kinetic Study Of Regulation Of Glua1 Homomeric And Heteromeric Ampa Receptors By 2,3-Benzodiazepines,
2017
University at Albany, State University of New York
A Kinetic Study Of Regulation Of Glua1 Homomeric And Heteromeric Ampa Receptors By 2,3-Benzodiazepines, Yin-Shuo (Andrew) Wu
Legacy Theses & Dissertations (2009 - 2024)
AMPA receptors are a subtype of the ionotropic glutamate receptor family. They are ligand-gated or glutamate-activated, transmembrane ion channels that mediate the majority of excitatory synaptic transmission in the central nervous system. AMPA receptors are essential for neuronal development and brain functions, including learning and memory. Over-activation of calcium permeable AMPA receptors has been linked to some neurological diseases such as stroke, Alzheimer’s disease and amyotrophic lateral sclerosis. Inhibitors of glutamate receptors are therefore drug candidates for the potential treatment of these neurological diseases. One of the most promising classes of AMPA receptor antagonists is 2,3-benzodiazepine derivatives, thought to be …
Approaches Toward Novel 1,2,3-Triazole Sensors For The Detection Of Anions And Heavy Metal Cations,
2017
Georgia Southern University
Approaches Toward Novel 1,2,3-Triazole Sensors For The Detection Of Anions And Heavy Metal Cations, Richard D. Govan
Electronic Theses and Dissertations
Cations and anions play pivotal roles in biological and physiological processes, however an imbalance in concentration of any ion can be detrimental. Therefore, research into the selective recognition of anions and heavy metal cations has acquired much attention. One approach involves the use of chemosensors. Upon interaction with targeted analytes, chemosensors produce a distinct response, in some cases a fluorescent or colorimetric signal. The 1,2,3-triazole unit has much potential as a chemical sensor due to its unique photophysical properties. The specificity, selectivity, and signaling mechanism of triazole sensors can be tuned with conjugation in the motif and choice and placement …
Enhancement Of The Physicochemical Properties Of Pt(Dien)(Nucleobase) (2+) For Hivncp7 Targeting,
2017
Old Dominion University
Enhancement Of The Physicochemical Properties Of Pt(Dien)(Nucleobase) (2+) For Hivncp7 Targeting, S. D. Tsotsoros, P. B. Lutz, A. G. Daniel, E. J. Peterson, R. E. F. De Paiva, E. Rivera, Y. Qu, C. A. Bayse, N. P. Farrell
Chemistry & Biochemistry Faculty Publications
Physicochemical properties of coordination compounds can be exploited for molecular recognition of biomolecules. The inherent π-π stacking properties of [Pt(chelate)(N-donor)]2+([PtN4]) complexes were modulated by systematic variation of the chelate (diethylenetriamine and substituted derivatives) and N-donor (nucleobase or nucleoside) in the formally substitution-inert PtN4 coordination sphere. Approaches to target the HIV nucleocapsid protein HIVNCp7 are summarized building on (i) assessment of stacking interactions with simple tryptophan or tryptophan derivatives to (ii) the tryptophan-containing C-terminal zinc finger and (iii) to the full two-zinc finger peptide and its interactions with RNA and DNA. The xanthosine nucleoside was identified …
Improving Cavity Enhanced Spectroscopy Of Molecular Ions In The Mid-Infrared With Up-Conversion Detection And Brewster-Plate Spoilers,
2017
Old Dominion University
Improving Cavity Enhanced Spectroscopy Of Molecular Ions In The Mid-Infrared With Up-Conversion Detection And Brewster-Plate Spoilers, Charles R. Markus, Adam J. Perry, James N. Hodges, Benjamin J. Mccall
Chemistry & Biochemistry Faculty Publications
The performance of sensitive spectroscopic methods in the mid-IR is often limited by fringing due to parasitic etalons and the background noise in mid-infrared detectors. In particular, the technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy (NICE-OHVMS), which is capable of determining the frequencies of strong rovibrational transitions of molecular ions with sub-MHz uncertainty, needs improved sensitivity in order to probe weaker transitions. In this work, we have implemented up-conversion detection with NICE-OHVMS in the 3.2 - 3.9 μm region to enable the use of faster and more sensitive detectors which cover visible wavelengths. The higher bandwidth enabled …
In Situ Ph Determination Based On The Nmr Analysis Of ¹H-Nmr Signal Intensities And ¹⁹F-Nmr Chemical Shifts,
2017
Missouri University of Science and Technology
In Situ Ph Determination Based On The Nmr Analysis Of ¹H-Nmr Signal Intensities And ¹⁹F-Nmr Chemical Shifts, Ming Huang
Masters Theses
"The pH of an NMR sample can be measured directly by NMR experiments of signal intensities, chemical shifts, or relaxation time constants that depend on the pH. The 1H NMR peak intensities of the pH indicator phenolphthalein change as it changes from the OH-depleted form to the OH-rich form in the range of pH = 11.1 to 12.7. Because this range is rather small, another NMR technique was utilized based on 19F chemical shifts. The shift of F- in an aqueous solution of NaF changes in the alkaline range between pH = 11.0 and 14.0 and even …
Characterization And Application Of Hybrid Nanostructures For Enhanced Biological Imaging Using Fluorescence Microscopy Techniques,
2017
University of Kentucky
Characterization And Application Of Hybrid Nanostructures For Enhanced Biological Imaging Using Fluorescence Microscopy Techniques, William E. Martin
Theses and Dissertations--Chemistry
Fluorescence microscopy is a powerful tool for interpreting the structure and function of biomolecules, and their interactions with one another. Understanding fundamental biological mechanisms is important to the development of improved treatments for a variety of diseases. Fluorescent tags are used to track the motion and longevity of such events, with the ability to monitor several biomolecules at once. Currently, many of these studies are conducted using bulk measurements, or several biological events at the same time, because the added light from several emitters can more easily overcome the high fluorescence background inherent to biological systems. Although important in their …
