Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Engineering (300)
- Materials Science and Engineering (118)
- Physics (118)
- Chemical Engineering (115)
- Materials Chemistry (60)
-
- Civil and Environmental Engineering (41)
- Organic Chemistry (40)
- Physical Chemistry (38)
- Electrical and Computer Engineering (37)
- Life Sciences (31)
- Mechanical Engineering (29)
- Biochemical and Biomolecular Engineering (25)
- Petroleum Engineering (25)
- Aerospace Engineering (23)
- Inorganic Chemistry (23)
- Analytical Chemistry (21)
- Computer Sciences (18)
- Biology (16)
- Biochemistry, Biophysics, and Structural Biology (15)
- Architecture (14)
- Metallurgy (14)
- Numerical Analysis and Scientific Computing (14)
- Architectural Engineering (13)
- Earth Sciences (13)
- Geology (13)
- Polymer Chemistry (13)
- Nuclear Engineering (12)
- Biomedical Engineering and Bioengineering (10)
- Keyword
-
- Iron (17)
- Enantiomer separation (13)
- Aerogels (12)
- Mössbauer Spectroscopy (12)
- Melanoma (10)
-
- Neutron Diffraction (10)
- Chemistry (9)
- Magnetic Moments (9)
- Nanoparticles (9)
- Polymers (9)
- Magnetisation (8)
- Nuclear Magnetic Resonance (8)
- Quantum chemistry (8)
- Alzheimer's disease (7)
- Amino acids (7)
- Dermoscopy (7)
- Ferromagnetic Materials (7)
- Potential energy (7)
- Potential energy surfaces (7)
- Teicoplanin (7)
- Antiferromagnetic Materials (6)
- Article (6)
- Crystallography (6)
- Electrochemistry (6)
- Glutathione (6)
- Isotopes (6)
- Magnetic Susceptibility (6)
- Magnetism (6)
- Magnetization (6)
- Spectroscopy (6)
- Publication Year
- Publication
-
- Chemistry Faculty Research & Creative Works (939)
- Doctoral Dissertations (181)
- Masters Theses (131)
- Physics Faculty Research & Creative Works (79)
- UMR-MEC Conference on Energy / UMR-DNR Conference on Energy (52)
-
- Materials Science and Engineering Faculty Research & Creative Works (21)
- Opportunities for Undergraduate Research Experience Program (OURE) (20)
- Civil, Architectural and Environmental Engineering Faculty Research & Creative Works (19)
- Chemical and Biochemical Engineering Faculty Research & Creative Works (18)
- Mechanical and Aerospace Engineering Faculty Research & Creative Works (16)
- Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works (15)
- Undergraduate Research Conference at Missouri S&T (14)
- Electrical and Computer Engineering Faculty Research & Creative Works (13)
- Miners Solving for Tomorrow Research Conference (13)
- Bachelors Theses (9)
- Biological Sciences Faculty Research & Creative Works (5)
- Mining Engineering Faculty Research & Creative Works (4)
- Computer Science Faculty Research & Creative Works (2)
- Engineering Management and Systems Engineering Faculty Research & Creative Works (1)
- Mathematics and Statistics Faculty Research & Creative Works (1)
- Publication Type
Articles 751 - 780 of 1553
Full-Text Articles in Chemistry
Structural Evolution Of Ammonia Borane For Hydrogen Storage, Jinbo Yang, Jagat Lamsal, Qingsheng Cai, William B. Yelon, William Joseph James
Structural Evolution Of Ammonia Borane For Hydrogen Storage, Jinbo Yang, Jagat Lamsal, Qingsheng Cai, William B. Yelon, William Joseph James
Physics Faculty Research & Creative Works
We have studied the crystal structure of fully deuterated BH3NH3 using powder neutron diffraction at different temperatures. It is evident that an order-disorder phase transition occurs around 225 K. At low temperature, the compound crystallizes in the orthorhombic structure with space group Pnm21 and gradually transforms to a high temperature tetragonal structure with space group I4 mm above 225 K. At 16 K, the BD3-ND3 unit stacks along the c axis with a tilt angle of about 16° between the N-B bond and the c axis. As the temperature is increased, the BD3-ND3 groups start to reorient along the c …
The Decomposition Of Yba₂Cu₃O₇₋Δ Doped Into Ba₂Yruo₆, H. A. Blackstead, William B. Yelon, M. Kornecki, M. P. Smylie, P. J. Mcginn, Jinbo Yang, Qingsheng Cai, William Joseph James
The Decomposition Of Yba₂Cu₃O₇₋Δ Doped Into Ba₂Yruo₆, H. A. Blackstead, William B. Yelon, M. Kornecki, M. P. Smylie, P. J. Mcginn, Jinbo Yang, Qingsheng Cai, William Joseph James
Physics Faculty Research & Creative Works
One of the persistent criticisms of claims for observation of superconductivity in Ba2YRu1−uCuuO6 (O6) is that the diamagnetism is actually due to the decomposition of the material into YBa2Cu3O7−delta and other phases. We report a series of experiments in which YBa2Cu3O7−delta is doped into Ba2YRuO6 and carried through a series of sintering steps which were followed by magnetization, neutron diffraction, and scanning electron microscopy/microprobe measurements. It was found that the dopant YBa2Cu3O7−delta decomposed and failed to reform with cooling. It is concluded that the O6 phase is the stable high-temperature phase. The Cu released from the Y123 decomposition doped the …
Colossal Positive Magnetoresistance In A Doped Nearly Magnetic Semiconductor, Rongwei Hu, Karin Jessica Thomas, Yong Jae Lee, Thomas J. Vogt, Eun Sang Choi, Vesna F. Mitrovic, Raphäel P. Hermann, Fernande Grandjean, Paul C. Canfield, Jong Woo Kim, Alan I. Goldman, Cedomir Petrovic
Colossal Positive Magnetoresistance In A Doped Nearly Magnetic Semiconductor, Rongwei Hu, Karin Jessica Thomas, Yong Jae Lee, Thomas J. Vogt, Eun Sang Choi, Vesna F. Mitrovic, Raphäel P. Hermann, Fernande Grandjean, Paul C. Canfield, Jong Woo Kim, Alan I. Goldman, Cedomir Petrovic
Chemistry Faculty Research & Creative Works
We report on a positive colossal magnetoresistance (MR) induced by metallization of FeSb2, a nearly magnetic or “Kondo” semiconductor with 3d ions. We discuss the contribution of orbital MR and quantum interference to the enhanced magnetic field response of electrical resistivity.
Polyaniline Nanofiber-Based Gas Sensors, Zhe-Fei Li, Frank D. Blum, Massimo F. Bertino, Chang-Soo Kim
Polyaniline Nanofiber-Based Gas Sensors, Zhe-Fei Li, Frank D. Blum, Massimo F. Bertino, Chang-Soo Kim
Chemistry Faculty Research & Creative Works
There has been recent interest in conducting polymers that have very promising chemical and electrical applications. Some of these polymers have shown great potential for use in sensors.1 Polyaniline is one particular example of a prospective material. In our laboratory, we have studied the synthesis of polyaniline nanofibers. We have carried out one-pot syntheses to obtain polyaniline nanofibers in aqueous solutions where the polymerization was influenced by γ-radiation2 or UV-radiation.3 This polymer can also be patterned with an appropriate photo mask. In our present report, polyaniline nanofiber thin film sensors have been fabricated in one step by employing UV-irradiation and …
Thermal Analysis Of Adsorbed Poly(Vinyl Acetate) On Silica, Boonta Hetayothin, Frank D. Blum
Thermal Analysis Of Adsorbed Poly(Vinyl Acetate) On Silica, Boonta Hetayothin, Frank D. Blum
Chemistry Faculty Research & Creative Works
The physical properties of polymers at interfaces can be quite different from those in bulk due to the interaction between the absorbed polymer and the surface. This phenomenon can be probed through the dynamic behavior of the polymer chains at the interface which can be experimentally probed by techniques such as nuclear magnetic resonance spectroscopy (NMR),1 viscoelasticity, and calorimetry. At the polymer-air interface, polymer chains have more flexibility than those at the polymer-substrate interface. On the other hand, at the silica-polymer interface, where chains are more restricted on the surface, a higher glass transition temperature (Tg) results as compared with …
Assemblies Of Nanoparticles As 3d Scaffolds For New Materials Design: From Polymer Crosslinked Aerogels To Polymer Matrix Composites, Nicholas Leventis, Chariklia Sotiriou-Leventis, Sudhir Mulik, Vishal U. Patil, Dhairyashil Mohite, Yanli Zhang, Hongbing Lu
Assemblies Of Nanoparticles As 3d Scaffolds For New Materials Design: From Polymer Crosslinked Aerogels To Polymer Matrix Composites, Nicholas Leventis, Chariklia Sotiriou-Leventis, Sudhir Mulik, Vishal U. Patil, Dhairyashil Mohite, Yanli Zhang, Hongbing Lu
Chemistry Faculty Research & Creative Works
From a materials perspective, nanotechnology furnishes materials with useful macroscopic properties by manipulating matter in the 1-100 nm size regime. Improvements in performance in terms of strength, modulus and wetability are accomplished by, for example, introducing nanoparticles as fillers in plastics . Two issues that usually interfere with optimal materials performance are agglomeration of the nanoparticles and materials compatibility. Agglomeration cancels the advantage of using nanoparticulate matter as dopant, while lack of materials compatibility introduces a discontinuity at the polymer/dopant interface from where failure may begin. Agglomeration is encountered with surfactants that keep nanoparticles dispersed, while materials compatibility is improved …
Dynamics Of Adsorbed Pma-D₃ - Effect Of Substrate, Frank D. Blum, Burak Metin, Macduff O. Okuom
Dynamics Of Adsorbed Pma-D₃ - Effect Of Substrate, Frank D. Blum, Burak Metin, Macduff O. Okuom
Chemistry Faculty Research & Creative Works
In the last few years, our group has focused much of our attention on studying the dynamics of polymers adsorbed at interfaces. Much of our work, to date has been on labeled poly(vinyl acetate)-d3 (PVAc-d3)1 and poly(methyl acrylate)-d3 (PMA-d3)2 on silica. We have been able to probe the effects of adsorbed amount,3 molecular mass,4,5 and the effect of overlayer.6 These studies have provided a view of the adsorbed polymer consistent with a motional gradient in the layer with the more mobile segments being those at the air-polymer interface and the less-mobile segments at the substratepolymer interface. However, we have not …
Adhesion Enhancement Of Polymeric Films On Glass Surfaces By A Silane Derivative Of Azobisisobutyronitrile (Aibn)., Sudhir Mulik, Chariklia Sotiriou-Leventis, Nicholas Leventis
Adhesion Enhancement Of Polymeric Films On Glass Surfaces By A Silane Derivative Of Azobisisobutyronitrile (Aibn)., Sudhir Mulik, Chariklia Sotiriou-Leventis, Nicholas Leventis
Chemistry Faculty Research & Creative Works
Adhesion of polymeric films on surfaces can be due to a combination of van der Waals, electrostatic or covalent interactions between the two materials. The interfacial adhesion between a polymer film and glass or metal can be improved by using a broad class of silane coupling agents. Typically, silane coupling compounds used for adhesion improvement have structure similar to (R´O)3-Si-R, where R´O- is an alkoxy group and -R is an organofunctional group. Under appropriate reaction conditions alkoxy groups condense with hydroxyl groups available on the surface, resulting in surfaces decorated with organofunctional -R groups, which promote formation of covalent bonding …
Glass Transition Behavior Of Poly(Methyl Acrylate) End-Grafted By Atrp To Amorphous Silica, Manikantan B. Nair, Frank D. Blum
Glass Transition Behavior Of Poly(Methyl Acrylate) End-Grafted By Atrp To Amorphous Silica, 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 …
Modeling The Fate Of Pharmaceuticals And Personal Care Products In Sewage Treatment Plants, Craig D. Adams
Modeling The Fate Of Pharmaceuticals And Personal Care Products In Sewage Treatment Plants, Craig D. Adams
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Chemical fate models can be used to estimate the transformation reactions and the partitioning behavior of pharmaceuticals and personal care products (PPCPs) in sewage treatment plants (STPs). Modeling the fate of PPCPs in a STP requires parameters such as rate constants or partition coefficients that are often unique to a specific STP, and that may exhibit significant temporal variability. Chemical fate models provide both a valuable test of our understanding of the fundamental underlying mechanisms regarding the fate of PPCPs in STPs, as well as a means of providing both qualitative and quantitative estimates for PPCP removal. This paper is …
X-Ray Lithography Of Metal And Semiconductor Nanoparticles, Nicholas Leventis, Suchi Guha, Massimo F. Bertino, Raghuveer Reddy Gadipalli, Brian R. Heckman, John Katsoudas, Ralu Divan, Lane A. Martin, Derrick C. Mancini
X-Ray Lithography Of Metal And Semiconductor Nanoparticles, Nicholas Leventis, Suchi Guha, Massimo F. Bertino, Raghuveer Reddy Gadipalli, Brian R. Heckman, John Katsoudas, Ralu Divan, Lane A. Martin, Derrick C. Mancini
Physics Faculty Research & Creative Works
In the last few years, a considerable amount of research has focused on the three-dimensional fabrication of contacts and electronic devices. Most techniques, however, are essentially based on photoreduction, and are limited to noble- and semi-noble metals. We present here a general method that allows patterning of porous matrices in 3D with metal, but also with semiconductor nanoparticles which is of potential relevance for microfabrication applications. In our method, the pore-filling solvent of a sol-gel material is exchanged with a solution of precursors. The precursors are photodissociated and nanoparticles are formed when the monoliths are irradiated. In a series of …
Compressive Behavior Of Crosslinked Mesoporous Silica Aerogels At High Strain Rates, Hongbing Lu, H. Luo, Sudhir Mulik, Chariklia Sotiriou-Leventis, Nicholas Leventis
Compressive Behavior Of Crosslinked Mesoporous Silica Aerogels At High Strain Rates, Hongbing Lu, H. Luo, Sudhir Mulik, Chariklia Sotiriou-Leventis, Nicholas Leventis
Chemistry Faculty Research & Creative Works
Aerogels are low-density mesoporous materials with exceptionally low dielectric constants, low thermal conductivities (up to 40 times better thermal insulators than the best fiberglass) and high acoustic impedance. Their practical applications, however, have been slow due to their hydrophilicity and brittleness. The fragility problem was resolved by nanocasting a ~2-4 nm thick polymer layer on the skeletal silica nanoparticles that strengthens the weak inter-nanopartical necks. The thin polymer coats conformally the skeletal framework without clogging the mesopores and reinforces the structure by chemically crosslinking the nanoparticles. With a density increase by only three times, crosslinking aerogels have the flexural strength …
Simulation Of The Evolution Of The Nanostructure Of Crosslinked Silica-Aerogels Under Compression, Hongbing Lu, Boshen Fu, Nitin Daphalapurkar, Jay Hanan, Nicholas Leventis, Chariklia Sotiriou-Leventis
Simulation Of The Evolution Of The Nanostructure Of Crosslinked Silica-Aerogels Under Compression, Hongbing Lu, Boshen Fu, Nitin Daphalapurkar, Jay Hanan, Nicholas Leventis, Chariklia Sotiriou-Leventis
Chemistry Faculty Research & Creative Works
Silica-aerogels are ultra-low-density assemblies of silica nanoparticles, and possess superior acoustic, specific energy absorption and thermal insulation properties. A new class of aerogels encapsulated with polymer is classified as crosslinked silica-aerogels. Manufacturing of such crosslinked silica-aerogel structures, depending on the type and shape of the nanoparticles, the polymer cross-linker and the chemistry in use, yields structures with vastly different morphologies and a wide range of mechanical behavior. With this, it has become necessary to understand the nanostructure / macroscopic properties relationship. Modeling of the aerogel material properties from mesoscale and up approach is needed, which is not considered by the …
Dynamics Of Pipa-D₇ On Silica Surface, Piyawan Krisanangkura, Frank D. Blum
Dynamics Of Pipa-D₇ On Silica Surface, Piyawan Krisanangkura, Frank D. Blum
Chemistry Faculty Research & Creative Works
Molecular motion of polymer chains is an important determinant in understanding the physical properties of polymeric materials. Glass transition temperature (Tg) is a physical property of polymers, which is of primary interest. The study of the dynamics of polymer segments assists in understanding the dependence of Tg on polymer structure.1 For decades, studies have addressed the molecular motion in various polymers. Some of them have probed the dynamics of polymer backbones.2,3 the properties of a polymer at an interface may change because of the type of polymer, the substrate, or other variables. The side chain of a polymer can also …
Obscurant Oil Characterization Produced Through Vaporization By Exhaust Gas Of Mini-Jet Turbine Engine, Hossein Daniel Bahaghighat
Obscurant Oil Characterization Produced Through Vaporization By Exhaust Gas Of Mini-Jet Turbine Engine, Hossein Daniel Bahaghighat
Masters Theses
"Obscurants have been used for centuries to conceal and protect military assets from direct enemy attack, or as a signal between units. Obscurants still play a significant role in protecting soldiers on the battlefield. This research was geared towards development of highly efficient man portable obscurant generation system to demonstrate its use with biogenic oils as the obscurants. The research reported in the thesis was directed evaluating the performance of a mini-jet based generator in the laboratory and field with two different obscurant oils, Fog Oil (FO) the oil used by the US Army at present and potential replacement oil …
Polymer Reinforced Aerogels And Composites A. Polyimide Crosslinked Aerogels B. Silica-Polymethylmethacrylate Composites, Vishal U. Patil
Polymer Reinforced Aerogels And Composites A. Polyimide Crosslinked Aerogels B. Silica-Polymethylmethacrylate Composites, Vishal U. Patil
Masters Theses
"Crosslinking of aerogels is a promising approach to combine the advantages of inorganic and polymeric materials. In the present study, two types of polyimide-silica hybrid aerogels, APTES-BTDA-MDA (mol ratio: 2:2:1) and APTES-BTDA-MDA (mol ratio: 2:3:2), were synthesized using a sol-gel process followed by heating in order to imidize the polyamic acid that is formed quickly and is covalently bonded to silica. The hybrid aerogels were made using 3-aminopropyltriethoxysilane (APTES) endcapped polyamic acids and tetramethoxysilane (TMOS) as precursors. Polyimide crosslinked aerogels were characterized by TGA, SEM, FT-IR, BET, solid state NMR and gas pycnometry. These hybrid aerogels exhibit high thermal stability …
A Rapid Method For Determination Of Alpha Hydroxy Acids In Seawater And Biological Fluids At Trace Levels, Ryan Lee Schwiderski
A Rapid Method For Determination Of Alpha Hydroxy Acids In Seawater And Biological Fluids At Trace Levels, Ryan Lee Schwiderski
Masters Theses
"Alpha hydroxy acids (AHAs) - carboxylic acids with a hydroxyl substitution on the alpha carbon are an important class of molecules. Hydroxy Methyl Thiobutanoic Acid (HMTBA) is an α-hydroxy analog of essential amino acid methionine; it finds extensive use as a feed supplement for avian and bovine species. Efficacy of alpha hydroxy acid uptake is important for nutritional studies and such studies rely on accurate and precise methods for determination of these chemicals in biological samples. Several methods for AHAs determination have been reported, however, the methods are tedious, requiring multiple sample preparation steps. Experiments reported in this thesis were …
A Tour-De-Force In Polymer Crosslinked Aerogels, Sudhir Mulik
A Tour-De-Force In Polymer Crosslinked Aerogels, Sudhir Mulik
Doctoral Dissertations
"In the quest of building mechanically strong materials with low density and high porosity, polymer crosslinked aerogels stand as the most promising nano-engineered examples. Covalent attachment of polymers and bridging of skeletal nanoparticles of typical aerogels is demonstrated by using surface initiated polymerization (SIP) with a bidentate free-radical initiator structurally related to azobisisobutyronitrile (AIBN) and confined on mesoporous silica surfaces. Different monomers were introduced in the mesopores and upon heating at 70⁰C, all mesoporous surfaces throughout the entire skeletal framework were coated conformally with a 10-12 nm thick polymer layer indistinguishable spectroscopically from the respective commercial bulk materials. The new …
The Effect Of Free Chlorine And Monochloramine On Lead In Drinking Water And Epitaxial Electrodeposition Of Tin Sulfide, Sansanee Boonsalee
The Effect Of Free Chlorine And Monochloramine On Lead In Drinking Water And Epitaxial Electrodeposition Of Tin Sulfide, Sansanee Boonsalee
Doctoral Dissertations
"Electrochemical deposition is utilized in various electronic and photovoltaic applications and in the protective coating industries. This dissertation primarily addresses the environmental aspects of electrochemical deposition. In the first part of this study, Pb dissolution in drinking water was investigated in the presence of two disinfectants: free chlorine (in the form of HOCI/OCr) and monochloramine (NH₂Cl). In the second part of this study, epitaxial SnS nanodisks were electrodeposited onto a Au(100) substrate. Water utility systems use either free chlorine or monochloramine in their disinfection program. Whereas free chlorine reacts with natural organic matter in the water to produce halogenated organic …
Synthesis And Evaluation Of Vegetable (Soybean) Oil Based Epoxy Resin For Beverage Can Coating And Enzymatic Synthesis And Characterization Of Tailored N&C End Protected Oligopeptides, Ying Gao
Doctoral Dissertations
"Research described in this dissertation covers two topics. Part-I is related to the development of a soybean oil based epoxy resin and its application in beverage can coatings. Interior surfaces of beverage can are invariably coated with polymer coating. The most commonly used coatings at present are derived from bisphenol A (BPA) based epoxy reins. However, due to perceived endocrine disrupting nature of BPA and consequential adverse effects on humans and wildlife concerns for the use of BPA based coatings and its leaching into beverages have been expressed. The research in the first part describes the synthesis and evaluation of …
Weak Ferromagnetism In Fe₁₋ₓcoₓsb₂, Rongwei Hu, Raphäel P. Hermann, Fernande Grandjean, Yong Jae Lee, John B. Warren, Vesna F. Mitrovic, Cedomir Petrovic
Weak Ferromagnetism In Fe₁₋ₓcoₓsb₂, Rongwei Hu, Raphäel P. Hermann, Fernande Grandjean, Yong Jae Lee, John B. Warren, Vesna F. Mitrovic, Cedomir Petrovic
Chemistry Faculty Research & Creative Works
Weak ferromagnetism in Fe1-xCoxSb2 is studied by magnetization and Mössbauer measurements. A small spontaneous magnetic moment of the order of ~ 10-3µB appears along the b axis for 0.2 ≤ x ≤ 0.4. Based on a structural analysis, we argue against extrinsic sources of weak ferromagnetism. We discuss our results in the framework of the nearly magnetic electronic structure of the parent compound FeSb2.
⁵⁷Fe Mössbauer Spectral And Muon Spin Relaxation Study Of The Magnetodynamics Of Monodispersed Γ-Fe₂O₃ Nanoparticles, Leïla Rebbouh, Raphäel P. Hermann, Fernande Grandjean, Taeghwan Hyeon, Kwangjin An, Alex Amato, Gary J. Long
⁵⁷Fe Mössbauer Spectral And Muon Spin Relaxation Study Of The Magnetodynamics Of Monodispersed Γ-Fe₂O₃ Nanoparticles, Leïla Rebbouh, Raphäel P. Hermann, Fernande Grandjean, Taeghwan Hyeon, Kwangjin An, Alex Amato, Gary J. Long
Chemistry Faculty Research & Creative Works
The Mössbauer spectra of monodispersed iron oxide nanoparticles with diameters of 4, 7, 9, and 11 nm have been measured between 4.2 and 315 K and fitted within the formalism for stochastic fluctuations of the hyperfine Hamiltonian. In this model, the hyperfine field is assumed to relax between the six ±x, ±y, and ±z directions in space with a distribution of relaxation rates that is temperature dependent. Muon spin relaxation measurements have been carried out on the 9 nm particles between 4.2 and 295 K. Both techniques reveal three regimes in the magnetic dynamics of these nanoparticles. In the low-temperature …
Ammonia Elimination From Protonated Nucleobases And Related Synthetic Substrates, Ming Qian, Shuo Yang, Hong Wu, Papiya S. Majumdar, Nathan D. Leigh, Rainer Glaser
Ammonia Elimination From Protonated Nucleobases And Related Synthetic Substrates, Ming Qian, Shuo Yang, Hong Wu, Papiya S. Majumdar, Nathan D. Leigh, Rainer Glaser
Chemistry Faculty Research & Creative Works
The results are reported of mass-spectrometric studies of the nucleobases adenine 1h (1, R = H), guanine 2h, and cytosine 3h. The protonated nucleobases are generated by electrospray ionization of adenosine 1r (1, R = ribose), guanosine 2r, and deoxycytidine 3d (3, R = deoxyribose) and their fragmentations were studied with tandem mass spectrometry. In contrast to previous EI-MS studies of the nucleobases, NH3 elimination does present a major path for the fragmentations of the ions [1h + H]+, [2h + H]+, and …
Electrostatic Force Microscopy Studies Of Boron-Doped Diamond Films, Santosh Gupta, O. A. Williams, Eric W. Bohannan
Electrostatic Force Microscopy Studies Of Boron-Doped Diamond Films, Santosh Gupta, O. A. Williams, Eric W. Bohannan
Computer Science Faculty Research & Creative Works
Much has been learned from electrochemical properties of boron-doped diamond (BDD) thin films synthesized using microwave plasma-assisted chemical vapor deposition about the factors influencing electrochemical activity, but some characteristics are still not entirely understood, such as its electrical conductivity in relation with microscale structure. Therefore, to effectively utilize these materials, understanding both the microscopic structure and physical (electrical, in particular) properties becomes indispensable. in addition to topography using atomic force microscopy, electrostatic force microscopy (EFM) in phase mode measuring the long-range electrostatic force gradients, helps to map the electrical conductivity heterogeneity of boron-doped micro-/nanocrystalline diamond surfaces. the mapping of electrical …
Antimony Vibrations In Skutterudites Probed By ¹²¹Sb Nuclear Inelastic Scattering, Hans Christian Wille, Raphäel P. Hermann, Ilya Sergueev, Olaf Leupold, Peter Van Der Linden, Brian C. Sales, Fernande Grandjean, Gary J. Long, Rudolf Rüffer, Yuri V. Shvyd'ko
Antimony Vibrations In Skutterudites Probed By ¹²¹Sb Nuclear Inelastic Scattering, Hans Christian Wille, Raphäel P. Hermann, Ilya Sergueev, Olaf Leupold, Peter Van Der Linden, Brian C. Sales, Fernande Grandjean, Gary J. Long, Rudolf Rüffer, Yuri V. Shvyd'ko
Chemistry Faculty Research & Creative Works
The specific lattice dynamic properties of antimony in the unfilled CoSb3 and filled EuFe4Sb12 skutterudites have been determined by nuclear inelastic scattering at the 121Sb nuclear resonance energy of 37.1298(2) keV with a 4.5 meV high-resolution backscattering sapphire monochromator. The Sb partial vibrational density of states (DOS) shows a maximum centered at 17 and 16 meV in CoSb3 and EuFe4Sb12, respectively. The difference between the Sb DOSs of CoSb3 and EuFe4Sb12 reveals that upon filling there is a transfer of 10% of the vibrational states toward …
Intrinsic Conformational Preferences Of And An Anomeric-Like Effect In 1-Substituted Silacyclohexanes, Abby Jones Weldon, Gregory S. Tschumper
Intrinsic Conformational Preferences Of And An Anomeric-Like Effect In 1-Substituted Silacyclohexanes, Abby Jones Weldon, Gregory S. Tschumper
Chemistry Faculty Research & Creative Works
A series of ab initio computations have been performed to estimate the CCSD(T) complete basis set limit of the axial/equatorial energy difference for the chair conformation of 1-fluoro, 1-chloro, 1-methyl, 1-hydroxy, and 1-methoxysilacyclohexanes. The equatorial conformation is more stable than the axial by 0.21 kcal mol-1 for 1-methylsilacyclohexane, while the axial position is more stable for 1-fluoro, 1-chloro, and 1-methoxysilacyclohexane (by 0.09, 0.40, and 0.15 kcal mol-1, respectively). The axial and equatorial orientations of 1-hydroxysilacyclohexane are nearly electronically isoenergetic (equatorial favored by 0.03 kcal mol-1). Zero-point vibrational energy corrections have very little effect on the relative energies (less …
Crystal And Electronic Structures Of The Complex Hydride Li₄Bn₃H₁₀, Jinbo Yang, X. J. Wang, Qingsheng Cai, William B. Yelon, William Joseph James
Crystal And Electronic Structures Of The Complex Hydride Li₄Bn₃H₁₀, Jinbo Yang, X. J. Wang, Qingsheng Cai, William B. Yelon, William Joseph James
Physics Faculty Research & Creative Works
The crystal structure of Li4BN3H10 was investigated using powder neutron diffraction with high sensitivity. The compound crystallizes in the cubic space group 213 with lattice parameters a=10.645 19(52) Å with an ordered arrangement of [NH2]−1 and [BH4]−1 anions in a molar ratio of 3:1. The bond lengths between the nearest nitrogen and hydrogen atoms are 1.04(4) and 1.14(4) Å. The bond angle between H(1)-N-H(2) is about 126(6)°, while those between H(3)-B-H(3) and H(3)-B-H(4) are about 109(6)°-110(7)°. There are three different Li sites surrounded by [NH2]−1 and [BH4]−1 anions in distorted tetrahedral configurations. The Li(3)-B and Li(3)-N bond distances are about …
Additive-Assisted, Cerium-Based, Corrosion-Resistant E-Coating, James O. Stoffer, Thomas J. O'Keefe, Eric L. Morris, Xuan Lin, Scott A. Hayes, Pu Yu
Additive-Assisted, Cerium-Based, Corrosion-Resistant E-Coating, James O. Stoffer, Thomas J. O'Keefe, Eric L. Morris, Xuan Lin, Scott A. Hayes, Pu Yu
Chemistry Faculty Research & Creative Works
Corrosion resistance of metallic components such as stainless steel components of vehicles, and especially aluminum- based components of aircraft, is enhanced by application of an e-coat paint or primer which is enhanced by incorporation of cerium ions into the e-coat electrolytic bath. The resulting overall coating includes a cerium-based layer under a cerium-enhanced e-coat paint or primer layer.
Mechanistic And Structural Studies Of H373q Flavocytochrome B2: Effects Of Mutating The Active Site Base, Chi Lin Tsai, Kuppan Gokulan, Pablo Sobrado, James C. Sacchettini, Paul F. Fitzpatrick
Mechanistic And Structural Studies Of H373q Flavocytochrome B2: Effects Of Mutating The Active Site Base, Chi Lin Tsai, Kuppan Gokulan, Pablo Sobrado, James C. Sacchettini, Paul F. Fitzpatrick
Chemistry Faculty Research & Creative Works
His373 in flavocytochrome b2 has been proposed to act as an active site base during the oxidation of lactate to pyruvate, most likely by removing the lactate hydroxyl proton. The effects of mutating this residue to glutamine have been determined to provide further insight into its role. The kcat and kcat/Klactate values for the mutant protein are 3 to 4 orders of magnitude smaller than the wild-type values, consistent with a critical role for His373. Similar effects are seen when the mutation is incorporated into the isolated flavin domain of the enzyme, narrowing the effects to lactate oxidation rather than …
A Polymorph Of K₄Ge₄Se₁₀, Amitava Choudhury, Sabine Strobel, Peter K. Dorhout
A Polymorph Of K₄Ge₄Se₁₀, Amitava Choudhury, Sabine Strobel, Peter K. Dorhout
Chemistry Faculty Research & Creative Works
A new monoclinic polymorph, ?-K4Ge4Se10 (tetra-potassium deca-selenidotetra-germanate), that crystallizes in space group P21/c has been isolated. The structure contains isolated super-tetra-hedral adamantane [Ge4Se10]4- clusters identical to those in the known K4Ge4Se10 polymorph (P21/m), held together in in the crystal structure by ionic inter-action with the K+ ions. The adamantane unit, [Ge4Se10] 4-, is formed by corner-sharing of four GeSe4 tetra-hedra, with average Ge -. Se distances of 2.378 and 2.281 Å for (Ge - Se)endo and (Ge - Se)exo, respectively. There are four crystallographically distinct K + ions in ?-K4Ge4Se10 having coordination numbers of 5, 7. and …