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Chemistry Faculty Research & Creative Works

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Full-Text Articles in Chemistry

Segmental Dynamics Of Poly(Vinyl Acetate)- D₃ Absorbed On Silica By Solid State 2hnmr: Effect Of Small Molecule Plasticizer, Rakesh R. Nambiar, Frank D. Blum Jan 2006

Segmental Dynamics Of Poly(Vinyl Acetate)- D₃ Absorbed On Silica By Solid State 2hnmr: Effect Of Small Molecule Plasticizer, Rakesh R. Nambiar, Frank D. Blum

Chemistry Faculty Research & Creative Works

There has been significant progress in understanding the behavior of polymeric thin films on surfaces. The change in the apparent glass transition temperature (Tg) of supported thin polymer films with thickness (Tg -nanoconfinement effect) has been widely studied over the last fifteen years. While many studies focused on the thickness dependence of Tg, there are other aspects which are important to understand in a nanoconfined polymer system. For example, polymeric photoresists contain small-molecule photoactive compounds, plasticizers, and processing aids. These components interact with the polymer chains and affect the segmental mobility, which, in turn, affects the Tg - nanoconfinement effect. …

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Adapting User Interface To Expedite Physician Order Entry: A Frontline To Ensure Patient Safety, Chiang S. Jao, Daniel B. Hier Jan 2006

Adapting User Interface To Expedite Physician Order Entry: A Frontline To Ensure Patient Safety, Chiang S. Jao, Daniel B. Hier

Chemistry Faculty Research & Creative Works

Preventable Medical Errors Are a Major Problem in Healthcare. Maintenance of Accurate Problem Lists and Drug Lists in the Electronic Medical Record is Critical to the Practice of Medicine and Patient Safety. We Built a Simulator of a Clinical Decision Support System that Automates the Process of Maintaining an Electronic Problem List by Processing Drug Order Requests from a Simulated Computerized Physician Order Entry System. Preliminary Results Revealed that the Productivity of the System Increased When the User Interface Was Improved. This Study Highlights the Importance of an Enhanced User Interface as a Frontline in Expediting Physician Data Entry, Streamlining …

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Electrochemical Deposition And Characterization Of Fe₃O₄ Films Produced By The Reduction Of Fe(Iii)-Triethanolamine, Hiten M. Kothari, Elizabeth A. Kulp, Steven J. Limmer, Philippe Poizot, Eric W. Bohannan, Jay A. Switzer Jan 2006

Electrochemical Deposition And Characterization Of Fe₃O₄ Films Produced By The Reduction Of Fe(Iii)-Triethanolamine, Hiten M. Kothari, Elizabeth A. Kulp, Steven J. Limmer, Philippe Poizot, Eric W. Bohannan, Jay A. Switzer

Chemistry Faculty Research & Creative Works

In this paper, we demonstrate that films of magnetite, Fe3O4, can be deposited by the electrochemical reduction of a Fe(III)-triethanolamine complex in aqueous alkaline solution. the films were deposited with a columnar microstructure and a [100] preferred orientation on stainless steel substrates. In-plane electrical transport and magnetoresistance measurements were performed on the films after they were stripped off onto glass substrates. the resistance of the films was dependent on the oxygen partial pressure. We attribute the increase in resistance in O2 and the decrease in resistance in Ar to the oxidation and reduction of grain …

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A Comparative Study Of The Properties Of Polar And Nonpolar Solvent/Solute/Polystyrene Solutions In Microwave Fields Via Molecular Dynamics, Mark J. Purdue, Macduff O. Okuom, Frank D. Blum, James M. D. Macelroy, D. F. O'Shea Jan 2006

A Comparative Study Of The Properties Of Polar And Nonpolar Solvent/Solute/Polystyrene Solutions In Microwave Fields Via Molecular Dynamics, Mark J. Purdue, Macduff O. Okuom, Frank D. Blum, James M. D. Macelroy, D. F. O'Shea

Chemistry Faculty Research & Creative Works

The influence of an applied microwave field on the dynamics of methylamine-dichloromethane (DCM) mixtures bound within atactic polystyrene (a-PS) over a range of polymer densities from 30 to 94 wt % polymer was examined using atomistic molecular dynamics simulations. This study is an extension of previous studies on methylamine transport in relatively polar polystyrene solutions of methanol and dimethylformamide [M. J. Purdue et al., J. Chem. Phys. 124, 204904 (2006)]. A direct comparison is made across the three types of polystyrene solutions. Consideration is given to both solvent and reagent transport within the polymer solutions under zero-field conditions and in …

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Acid-Catalyzed Time-Efficient Synthesis Of Resorcinol-Formaldehyde Aerogels And Crosslinking With Isocyanates, Sudhir Mulik, Chariklia Sotiriou-Leventis, Nicholas Leventis Jan 2006

Acid-Catalyzed Time-Efficient Synthesis Of Resorcinol-Formaldehyde Aerogels And Crosslinking With Isocyanates, Sudhir Mulik, Chariklia Sotiriou-Leventis, Nicholas Leventis

Chemistry Faculty Research & Creative Works

Aerogels are open-cell foams derived from supercritical fluid (SCF) drying of wet gels. Their large internal void space is responsible for low thermal conductivity, high surface area and high acoustic impedance. Most aerogels are based on inorganic metal or semimetal oxide frameworks. Pekala and co-workers synthesized resorcinol-formaldehyde (RF) organic aerogels by poly-condensation of resorcinol with formaldehyde in the presence of Na2CO3 as base catalyst, followed by drying with SCF CO2. Low-density RF aerogels prepared by this method exhibit high porosities (>80%), high surface areas (400-900 m2g-1), ultrafine cell-size (<500 > Å) …

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Conformal Internal Coating Of Macroporous Co-Continuous Mcf-Silicas With Isocyanate Derived Polymers, Nicholas Leventis, Chariklia Sotiriou-Leventis, Xiaojiang Wang, Sudhir Mulik Jan 2006

Conformal Internal Coating Of Macroporous Co-Continuous Mcf-Silicas With Isocyanate Derived Polymers, Nicholas Leventis, Chariklia Sotiriou-Leventis, Xiaojiang Wang, Sudhir Mulik

Chemistry Faculty Research & Creative Works

Since their discovery in 1992,1,2 templating sol-gel silica with structuredirecting agents has resulted in new materials with ordered mesoporous (2-50 nm) structure that is investigated for application in areas as diverse as high surface area supports for caralysts or as nanostructured drug storage and release platforms.3 Structure-directing agents are typically surfactants ranging from cationic detergents such as alkyl-trimethylammonium salts with C8-C18 hydrocarbon chains to non-ionic tertiary amines, polyethylene oxide or amphiphilic triblock copolymers such as poly(ethyleneoxide)-blockpoly( propyleneoxide)-block-poly(ethyleneoxide) (e.g., Pluronic P123). Depending on the surfactant and the conditions (e.g., kind and concentration of catalyst) the structure of the mesopores may vary …

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Segmental Dynamics In Poly(Methyl Acrylate) On Silica: Molecular-Mass Effects, Burak Metin, Frank D. Blum Jan 2006

Segmental Dynamics In Poly(Methyl Acrylate) On Silica: Molecular-Mass Effects, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The effect of molecular mass on the segmental dynamics of poly(methyl acrylate) (PMA) adsorbed on silica was studied using deuterium quadrupole-echo nuclear magnetic resonance (NMR) and modulated differential scanning calorimetry. Samples adsorbed on silica (all about 1.5 mg PMA/m2 silica) were shown to have more restricted segmental mobility, and higher Tg's, than the corresponding bulk PMA samples. Around the glass-transition region, adsorbed samples exhibited segmental mobility, which could be classified as heterogeneous due to a superposition of more-mobile and less-mobile components present in the deuterium NMR spectra. This heterogeneity was consistent with a motional gradient with more-mobile segments near the …

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Residual Stress Distribution, Intermolecular Force, And Frictional Coefficient Maps In Diamond Films: Processing-Structure-Mechanical Property Relationship, Sanju Gupta, Oliver Williams, R. J. Patel, Eric W. Bohannan, P. W. May Jan 2006

Residual Stress Distribution, Intermolecular Force, And Frictional Coefficient Maps In Diamond Films: Processing-Structure-Mechanical Property Relationship, Sanju Gupta, Oliver Williams, R. J. Patel, Eric W. Bohannan, P. W. May

Chemistry Faculty Research & Creative Works

Carbon in its various forms, specifically nanocrystalline diamond, may become a key material for the manufacturing of micro- and nano-electromechanical (M/NEMS) devices in the 21st Century. in order to utilize effectively these materials for M/NEMS applications, understanding of their microscopic structure and physical properties (mechanical, in particular) become indispensable. the micro- and nanocrystalline diamond films were grown using hot-filament and microwave chemical vapor deposition techniques involving novel CH4 / [TMB for boron doping and H2S for sulfur incorporation] in high hydrogen dilution chemistry. to investigate residual stress distribution and intermolecular forces at the nanoscale, the films were characterized using Raman …

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Segmental Dynamics Of Poly(Isopropyl Acrylate)-D7 On Silica, Piyawan Krisanangkura, Frank D. Blum Jan 2006

Segmental Dynamics Of Poly(Isopropyl Acrylate)-D7 On Silica, Piyawan Krisanangkura, Frank D. Blum

Chemistry Faculty Research & Creative Works

For a polymer film deposited on a surface, the strength of the surfacesegment interaction affects the mobility of polymer-chain segments. The selfconsistent field lattice model of Scheutjens and Fleer,1 based on mean-field lattice models of polymer at interfaces,2 has been used to describe the distribution of conformations of polymers on surfaces. Adsorbed-polymer segments may be classified as belonging to loops, trains or tails. There are different techniques used to study the molecular motion of the polymer including modulated differential scanning calorimetry (MDSC)3 and nuclear magnetic resonance (NMR).4,5 in this work, solid-state deuterium (2H) NMR was used to characterize the polymer …

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Separation And Quantification Of N-Acetylcysteine-Amide (Naca) By Hplc With Fluorescence Detection, Wei Wu, Glenn Goldstein, Craig D. Adams, Richard H. Matthews, Nuran Ercal Jan 2006

Separation And Quantification Of N-Acetylcysteine-Amide (Naca) By Hplc With Fluorescence Detection, Wei Wu, Glenn Goldstein, Craig D. Adams, Richard H. Matthews, Nuran Ercal

Chemistry Faculty Research & Creative Works

N-acetyl-l-cysteine (NAC) is a well-known antioxidant that is capable of facilitating glutathione (GSH) biosynthesis and replenishing intracellular GSH under oxidatively challenging circumstances. N-acetyl-cysteine-amide (NACA), the amide form of NAC, is a newly designed and synthesized thiol-containing compound which is believed to be more lipophilic and permeable through cell membranes than NAC. The metabolic and antioxidant effects of these compounds in vitro and in vivo are under investigation. However, an analytical method that can separate and quantify both compounds simultaneously is not yet available, to the best of our knowledge. Because of their structural similarities, the two compounds are difficult to …

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Intrinsic Conformational Preferences Of Substituted Cyclohexanes And Tetrahydropyrans Evaluated At The Ccsd(T) Complete Basis Set Limit: Implications For The Anomeric Effect, Abby Jones Weldon, Trisha L. Vickrey, Gregory S. Tschumper Dec 2005

Intrinsic Conformational Preferences Of Substituted Cyclohexanes And Tetrahydropyrans Evaluated At The Ccsd(T) Complete Basis Set Limit: Implications For The Anomeric Effect, Abby Jones Weldon, Trisha L. Vickrey, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

A series of MP2 and CCSD(T) computations have been carried out with correlation consistent basis sets as large as aug-cc-pV5Z to determine the intrinsic equatorial-axial conformational preference of CH 3-, F-, OCH 3-, and OH-substituted cyclohexane and tetrahydropyran rings. The high-accuracy relative electronic energies reported here shed new light on the intrinsic energetics of these cyclic prototypes for the anomeric effect. At the CCSD(T) complete basis set (CBS) limit, the energy of the equatorial conformation relative to the axial position (ΔE CCSD(T)CBC) is -0.75, -0.20, -0.21, and -0.56 kcal mol -1 in methyl-, fluoro-, methoxy-, and hydroxy cyclohexane, respectively, while …

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Neutron And Nuclear Inelastic Scattering Study Of The Einstein Oscillators In Ba-, Sr-, And Eu-Filled Germanium Clathrates, Raphaël P. Hermann, Werner Schweika, Olaf Leupold, Rudolf Rüffer, George S. Nolas, Fernande Grandjean, Gary J. Long Nov 2005

Neutron And Nuclear Inelastic Scattering Study Of The Einstein Oscillators In Ba-, Sr-, And Eu-Filled Germanium Clathrates, Raphaël P. Hermann, Werner Schweika, Olaf Leupold, Rudolf Rüffer, George S. Nolas, Fernande Grandjean, Gary J. Long

Chemistry Faculty Research & Creative Works

Inelastic neutron scattering measurements on Ba8Ga16Ge30 and Sr8Ga16Ge30 indicate the presence of soft local modes with Einstein oscillator energies of 4.9±0.1 and 4.4±0.1meV, modes which are associated with the lowest “rattling” mode of the Ba(B) and Sr(B) guests, respectively. Nuclear inelastic scattering measurements on Eu8Ga16Ge30 yield Einstein oscillator energies of between 3.0±0.3 and 7.5±1.2meV for the different modes of the Eu guests. Further, the resonant character of the measurements on Eu8Ga16Ge30 reveals, without question, that neither of the Eu guests …

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Computational And Esr Studies Of Electron Attachment To Decafluorocyclopentane, Octafluorocyclobutane, And Hexafluorocyclopropane: Electron Affinities Of The Molecules And The Structures Of Their Stable Negative Ions As Determined From ¹³C And 19f Hyperfine Coupling Constants, Adel M. Elsohly, Gregory S. Tschumper, Richard A. Crocombe, Jih Tzong Wang, Ffrancon Williams Aug 2005

Computational And Esr Studies Of Electron Attachment To Decafluorocyclopentane, Octafluorocyclobutane, And Hexafluorocyclopropane: Electron Affinities Of The Molecules And The Structures Of Their Stable Negative Ions As Determined From ¹³C And 19f Hyperfine Coupling Constants, Adel M. Elsohly, Gregory S. Tschumper, Richard A. Crocombe, Jih Tzong Wang, Ffrancon Williams

Chemistry Faculty Research & Creative Works

High-resolution ESR spectra of the ground-state negative ions of hexafluoro cyclopropane (c-C3F6.-), octafluorocyclobutane (c-C4F8.-), and decafluorocyclopentane (c-C5F10.-) are reported and their isotropic 19F hyperfine coupling constants (hfcc) of 198.6 ± 0.4 G, 147.6 ± 0.4 G, and 117.9 ± 0.4 G, respectively, are in inverse ratio to the total number of fluorine atoms per anion. Together with the small value of 5.2 ± 0.4 G determined for the isotropic 13C hfcc of c-C4F8.-, these results indicate that in each case the singly occupied molecular orbital (SOMO) is delocalized over the equivalent fluorine's and possesses a nodal plane through the carbon …

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Integrated Quantum Mechanical Approaches For Extended Π Systems: Multicentered Qm/Qm Studies Of The Cyanogen And Diacetylene Trimers, Brian W. Hopkins, Gregory S. Tschumper May 2005

Integrated Quantum Mechanical Approaches For Extended Π Systems: Multicentered Qm/Qm Studies Of The Cyanogen And Diacetylene Trimers, Brian W. Hopkins, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

A multicentered integrated quantum mechanical (MC QM/QM) scheme that can accurately treat extended π systems is presented. The trimers of cyanogen (NC-CN) and diacetylene (H-CC-CC-H) are studied in seven geometries. MC QM/QM calculations reproduce CCSD(T) binding energies within 0.04 kcal mol-1. In contrast, MP2 substantially overestimates these interaction energies. An MC QM/QM version of the substituent value test is introduced, and the error in MC QM/QM results is discussed in this context. The results for these systems suggest that MC QM/QM may be a powerful tool in the study of extended π systems and other weakly bound clusters. …

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Bimetallic Pt-Ag And Pd-Ag Nanoparticles, Frank D. Blum, Akira Tokuhiro, Massimo F. Bertino, Carmen M. Doudna Apr 2005

Bimetallic Pt-Ag And Pd-Ag Nanoparticles, Frank D. Blum, Akira Tokuhiro, Massimo F. Bertino, Carmen M. Doudna

Chemistry Faculty Research & Creative Works

We report studies of bimetallic nanoparticles with 15%-16% atomic crystal parameters size mismatch. The degree of alloying was probed in a 2-nm Pt core (smallest attainable core size) of Pt-Ag nanoparticles (completely immiscible in bulk) and 20-nm-diameter Pd-Ag nanowires (completely miscible in bulk). Particles were synthesized radiolytically, and depending on the initial parameters, they assume spherical or cylindrical (nanowire) morphologies. In all cases, the metals are seen to follow their bulk alloying characteristics. Pt and Ag segregate in both spherical and wire forms, which indicates that strain due to crystallographic mismatch overcomes the excess surface free energy in the small …

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How To Choose One-Dimensional Basis Functions So That A Very Efficient Multidimensional Basis May Be Extracted From A Direct Product Of The One-Dimensional Functions: Energy Levels Of Coupled Systems With As Many As 16 Coordinates, Richard Dawes, Tucker Carrington Jr. Apr 2005

How To Choose One-Dimensional Basis Functions So That A Very Efficient Multidimensional Basis May Be Extracted From A Direct Product Of The One-Dimensional Functions: Energy Levels Of Coupled Systems With As Many As 16 Coordinates, Richard Dawes, Tucker Carrington Jr.

Chemistry Faculty Research & Creative Works

In this paper we propose a scheme for choosing basis functions for quantum dynamics calculations. Direct product bases are frequently used. The number of direct product functions required to converge a spectrum, compute a rate constant, etc., is so large that direct product calculations are impossible for molecules or reacting systems with more than four atoms. It is common to extract a smaller working basis from a huge direct product basis by removing some of the product functions. We advocate a build and prune strategy of this type. the one-dimensional (1D) functions from which we build the direct product basis …

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Strongly Decoupled Europium And Iron Vibrational Modes In Filled Skutterudites, Gary J. Long, Raphäel P. Hermann, Fernande Grandjean, Ercan E. Alp, Wolfgang Sturhahn, Charles E. Johnson, Dennis E. Brown, Olaf Leupold, Rudolf Rüffer Apr 2005

Strongly Decoupled Europium And Iron Vibrational Modes In Filled Skutterudites, Gary J. Long, Raphäel P. Hermann, Fernande Grandjean, Ercan E. Alp, Wolfgang Sturhahn, Charles E. Johnson, Dennis E. Brown, Olaf Leupold, Rudolf Rüffer

Chemistry Faculty Research & Creative Works

The europium partial vibrational density of states (DOS) in EuFe4Sb12 and the iron partial vibrational DOS in both EuFe4Sb12 and Ce57Fe4Sb12 have been obtained by nuclear inelastic scattering. The results reveal the strong independence of the iron and rare-earth vibrational modes. The cage filling europium only participates significantly to the low-energy local vibrational modes. The force constants have been obtained from the measured probability of nuclear absorption. The energies of the peaks in the europium and iron DOS are in excellent agreement with the calculated DOS in LaFe4 …

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Basic Region Of Residues 228-231 Of Protein Kinase Ck1Α Is Involved In Its Interaction With Axin: Binding To Axin Does Not Affect The Kinase Activity, Pablo Sobrado, Ana Jedlicki, Victor H. Bustos, Catherine C. Allende, Jorge E. Allende Feb 2005

Basic Region Of Residues 228-231 Of Protein Kinase Ck1Α Is Involved In Its Interaction With Axin: Binding To Axin Does Not Affect The Kinase Activity, Pablo Sobrado, Ana Jedlicki, Victor H. Bustos, Catherine C. Allende, Jorge E. Allende

Chemistry Faculty Research & Creative Works

Protein kinase CK1, also known as casein kinase 1, participates in the phosphorylation of β-catenin, which regulates the functioning of the Wnt signaling cascade involved in embryogenesis and carcinogenesis. β-catenin phosphorylation occurs in a multiprotein complex assembled on the scaffold protein axin. The interaction of CK1α from Dani rerio with mouse-axin has been studied using a pull-down assay that uses fragments of axin fused to glutathione S transferase, which is bound to glutathione sepharose beads. The results indicate that the three lysines present in the basic region of residues 228-231 of CK1α are necessary for the binding of CK1 to …

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Synthesis Of Gold Nanoparticles Attached To Polypyrrole Nanofibers, Sunil K. Pillalamarri, Frank D. Blum, Massimo F. Bertino Jan 2005

Synthesis Of Gold Nanoparticles Attached To Polypyrrole Nanofibers, Sunil K. Pillalamarri, Frank D. Blum, Massimo F. Bertino

Chemistry Faculty Research & Creative Works

Polypyrrole is a frequently studied conducting polymer due to its application in sensing and catalysis.1 Polypyrrole is considered among the most promising conductive polymers due to its stability and ease of conversion between conducting and insulating forms.2 Different chemical and electrochemical methods are generally used in the synthesis of polypyrrole.2 Despite many interesting applications, the use of polypyrrole is limited because of difficulty in processing it. Several approaches have been explored to improve the ability to process polypyrrole, including the use of emulsion, inverse emulsion, steric stabilizer, and microemulsion methods.1 Several reports have also been published on the synthesis of …

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Copolymers And Blends Of Methyl Acrylate And Acrylic Isobutyl Poss Nanomaterials, Manikantan B. Nair, Frank D. Blum Jan 2005

Copolymers And Blends Of Methyl Acrylate And Acrylic Isobutyl Poss Nanomaterials, Manikantan B. Nair, Frank D. Blum

Chemistry Faculty Research & Creative Works

Ultra-thin polymer films attached to solid substrates (supported films) have attracted significant interest in recent years. Supported films are used in the design of advanced materials like photoresists, lubricants and other electronic devices. Glass transition temperatures (Tgs) of supported polymer films have also been of significant interest. The Tg has been shown to depend on the thickness of the polymer film on the surface and the inherent nature of the surface. The effect of end-grafting of a polymer chain to a surface, on the Tg of the polymer has been studied previously.1 Reports on the study of glass transition behaviors …

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Fourier Transform Infrared Analysis Of Hydroxyl Content Of Hydrothermally Processed Heteroepitaxial Barium Titanate Films, Sandeep K. Patil, Nipun Shah, Frank D. Blum, M. N. Rahaman Jan 2005

Fourier Transform Infrared Analysis Of Hydroxyl Content Of Hydrothermally Processed Heteroepitaxial Barium Titanate Films, Sandeep K. Patil, Nipun Shah, Frank D. Blum, M. N. Rahaman

Chemistry Faculty Research & Creative Works

The concentration of hydroxyl (-OH) groups in epitaxial barium titanate (BaTiO3) films (thickness ≈ 200 nm), deposited on single-crystal strontium titanate (SrTiO3) at 150 °C by a hydrothermal technique, was investigated using x-ray photoelectron spectroscopy and Fourier transform infrared (FTIR) spectroscopy. After hydrothermal treatment, a broad FTIR resonance for the hydroxyl groups indicated a significant concentration of surface -OH groups in the films. The as-deposited films were subsequently treated hydrothermally with D2O, and the kinetics of the exchange reaction between -OH incorporated into the film and -OD from the D2O were studied using FTIR. For reactions carried out intermittently, the …

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Effect Of Phosphoric Acid Anion Structure On The Corrosion Inhibition Of Steel By Polyaniline, Yasir Idlibi, Thomas P. Schuman, James O. Stoffer Jan 2005

Effect Of Phosphoric Acid Anion Structure On The Corrosion Inhibition Of Steel By Polyaniline, Yasir Idlibi, Thomas P. Schuman, James O. Stoffer

Chemistry Faculty Research & Creative Works

Conductive polymers such as polyaniline (PAni) have been examined as candidates for replacing the existing chromate systems. Protonation of emeraldine base creates polarons and bipolarons, single and paired radical cations, respectively, of higher bond energy levels within the molecular orbital band gap.' For a conductive coating, considerable delocalization of corrosion charge and potential may be obtained along or between the polymer chains, because of high electron mobility. Current corrosion systems based on polyaniline typically rely on sulfuric or sulfonic acids as a dopant material, since synthetic techniques utilize persulfates as the oxidant of choice. In our experience, sulfonic/sulfuric acid systems …

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An Hmm-Based Framework For Video Semantic Analysis, Gu Xu, Yu-Fei Ma, Hong-Jiang Zhang, Shiqiang Yang Jan 2005

An Hmm-Based Framework For Video Semantic Analysis, Gu Xu, Yu-Fei Ma, Hong-Jiang Zhang, Shiqiang Yang

Chemistry Faculty Research & Creative Works

Video semantic analysis is essential in video indexing and structuring. However, due to the lack of robust and generic algorithms, most of the existing works on semantic analysis are limited to specific domains. In this paper, we present a novel hidden Markove model (HMM)-based framework as a general solution to video semantic analysis. In the proposed framework, semantics in different granularities are mapped to a hierarchical model space, which is composed of detectors and connectors. In this manner, our model decomposes a complex analysis problem into simpler subproblems during the training process and automatically integrates those subproblems for recognition. The …

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Effect Of Plasticizer On Pvac-D3 Dynamics Using 2h Solid-State Nmr, Rakesh R. Nambiar, Frank D. Blum Jan 2005

Effect Of Plasticizer On Pvac-D3 Dynamics Using 2h Solid-State Nmr, Rakesh R. Nambiar, Frank D. Blum

Chemistry Faculty Research & Creative Works

Poly(vinyl acetate) (PVAc) is an important polymer for use in many applications due to its various bulk and surface characteristics. The structure of poly(vinyl acetate) results in a relatively low glass transition temperature (Tg) and makes it important for processing and applications such as paints, adhesives, thin films and surface coatings. Poly(vinyl acetate) can also be easily plasticized, widening its range of applications. The term "plasticizer" refers to a species that will decrease Tg of a polymer.1 Polymer-plasticizer systems have been studied for years and continue to be of current interest. The effects of polymer-plasticizer interactions2 and plasticizer structure3 on …

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Estimation Of Bound Carbonyls In Pmma-R-Ps Copolymers Adsorbed On Silica, Pavan K. Challa, Bing Zhang, Frank D. Blum Jan 2005

Estimation Of Bound Carbonyls In Pmma-R-Ps Copolymers Adsorbed On Silica, Pavan K. Challa, Bing Zhang, Frank D. Blum

Chemistry Faculty Research & Creative Works

The adsorption of random copolymers on solid surfaces is essential for developing good properties in composite materials. A good control and understanding of interfaces allows tuning of the properties of the individual components. Interfacial polymers are important in many industrial applications such as photoresists, protective coatings, metal insulator and semi-conductor insulator junctions, metal-filled polymer composites and polymer-lined metal containers for protective food packaging. The effect of the drying process,1 configuration and tacticity,2 molecular mass, density of surface hydroxyls,3 and adsorbed amounts4 have already been studied for interfacial polymers. The thermal characterization for polystyrene,5 PMMA11 and PMMA-r- PS6 copolymers adsorbed on …

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Magnetic Properties Of (Γ-Fe₂O₃)₈₀Ag₂₀ Nanocomposites Prepared In Reverse Micelles, Joan A. Wiemann, Jianbiao Dai, Jinke Tang, Gary J. Long, Leonard Spinu Jan 2005

Magnetic Properties Of (Γ-Fe₂O₃)₈₀Ag₂₀ Nanocomposites Prepared In Reverse Micelles, Joan A. Wiemann, Jianbiao Dai, Jinke Tang, Gary J. Long, Leonard Spinu

Chemistry Faculty Research & Creative Works

The magnetic properties of nanoparticles of gamma-Fe2O3 prepared by reverse micelles have been studied by dc magnetization, transverse ac susceptibility, and Mössbauer spectroscopy. The nanoparticles of gamma-Fe2O3 in the nanocomposite (gamma-Fe2O3)80Ag20 exhibit superparamagnetic behavior. The blocking temperatures determined by the three methods indicate the superparamagnetic nature of (gamma-Fe2O3)80Ag20 above 70-80 K and show correlation with measuring time. The average particle diameter obtained by transmission electron microscopy of the gamma-Fe2O3 particles is ~10 nm and that of the Ag particles is ~20 nm. The average particle size determined from the magnetic analyses for the gamma-Fe2O3 particles is ~12 nm. Mössbauer spectra …

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Segmental Dynamics In Poly(Methyl Acrylate)-D3 On Strongly And Weakly Adsorbing Silica Surfaces, Burak Metin, Frank D. Blum Jan 2005

Segmental Dynamics In Poly(Methyl Acrylate)-D3 On Strongly And Weakly Adsorbing Silica Surfaces, Burak Metin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The segmental dynamics of a polymer on a solid surface appears to be significantly different than that in bulk. The strength of the interaction between polymer segments and a solid surface is likely to be an important factor affecting the segmental mobility of the polymers. Studies of polymers on a weakly adsorbing surface would provide additional understanding of their motional characteristics on surfaces. In a recent NMR study by Rivillon et al., chain dynamics was seen to be different for samples, even when there was no specific interaction with the surface. Peanasky et al. have found a restricted segmental dynamics …

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Synthesis And Electropolymerization Of 2-(3-Thienylethyl)-3-Thiopheneacetate, Nicholas Leventis, Chariklia Sotiriou-Leventis, Sudhir Mulik, Amala Dass Jan 2005

Synthesis And Electropolymerization Of 2-(3-Thienylethyl)-3-Thiopheneacetate, Nicholas Leventis, Chariklia Sotiriou-Leventis, Sudhir Mulik, Amala Dass

Chemistry Faculty Research & Creative Works

Conducting polymers offer great promise in the development of electronic devices, displays and sensors. In that regard, biomolecules can be attached to these polymers via functional groups, but the presence of such groups oftentimes hinders polymerization.1-3 One strategy is to polymerize a functionalized monomer precursor of a conducting polymer, followed by reaction of the dangling functional groups of the polymer with appropriately functionalized labels. An attractive functionalized thiophene for that purpose is 3-thienylethanol. Unfortunately, however, this monomer is not polymerizable.1,2 Thus, 3-thienylethanol has been esterified, followed by co-polymerization with 3-methylthiophene (3-MT), and subsequent hydrolysis of the ester to the free …

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Nmr And Modulated Differential Scanning Calorimetry Of Adsorbed Poly(Methyl Acrylate) On Silica, Frank D. Blum, Burak Metin Jan 2005

Nmr And Modulated Differential Scanning Calorimetry Of Adsorbed Poly(Methyl Acrylate) On Silica, Frank D. Blum, Burak Metin

Chemistry Faculty Research & Creative Works

The interaction between polymers and solid substrates can be studied by a variety of techniques. The results from different experiments can be affected by the nature of the polymer, surface, polymer-surface interactions and, also, the experiment. A great deal has been learned about the behavior of polymers at interfaces, but there is also much to be learned about the interactions and how they affect the physical properties of adsorbed polymers. In the present study, we report both deuterium nuclear magnetic resonance (NMR) and modulated differential scanning calorimetry (MDSC) of poly(methyl acrylate) (PMA) adsorbed on Cab-O-Sil silica. The focus of this …

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Deuterium Nmr Studies Of Segmental Dynamics Of Anopore-Adsorbed Poly(Methyl Acrylate), Macduff O. Okuom, Frank D. Blum Jan 2005

Deuterium Nmr Studies Of Segmental Dynamics Of Anopore-Adsorbed Poly(Methyl Acrylate), Macduff O. Okuom, Frank D. Blum

Chemistry Faculty Research & Creative Works

Studies of segmental dynamics of polymers at interfaces provide a basis for understanding the properties of composite materials. Interfacial phenomena in multi-phase systems need to be understood as devices made from multi-phase polymeric systems become smaller. Various techniques have been used to investigate interfacial polymers at the air-polymer-solid interface; for example, ellipsometry,1 X-ray,2 and neutron reflectometry.3 These techniques typically characterize the structure (often the thickness) of the polymer layer and are normally used to determine the glass-transition temperature (Tg) through a break in the thicknesstemperature curve. There have been a few reports where the dynamics of polymers at the surface-air …

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