Chemistry Commons^™

Electrochemical Study On The Anodic Process Of Fes, Hong-Hui Xu, Hui Xu, Yong Du, Zhu Pan, Yun-He Zhang, Yu-De Shu

Journal of Electrochemistry

Ferrous sulfide (FeS) was synthesized with spectrum-pure Fe and S at high-temperature, and its anodic behaviors in the solution of 0.5 mol·L^-1 H₂SO₄ + 0.5 mol·L^-1 K₂SO₄ was studied by using voltage sweep and step voltage techniques. The effects of acidity on the anodic polarization curves of FeS were investigated. The transfer coefficient β and exchange current density I_0 in the anodic electrode process, and the solid diffusion coefficient D_Fe of Fe²⁺ in FeS were measured. And also the activation energies of anodic reaction at different voltages was also determined.

Substrates Made By Electrodeposition For Measuring Electrical Properties Of One Dimensional Nanomaterials, Jin-Xuan Liu, Juan Xiang, Zhong-Qun Tian, Bing-Wei Mao

Journal of Electrochemistry

A method to prepare alternating conducting/insulating substrates by electrodeposition-oxidation was established to facilitate I-E measurements of one-dimensional nanomaterial by CT-AFM. The prepared Au/CuO and HOPG/CuO substrates showed low roughness as well as high uniformity of the alternating conducting/insulating structure, Qualitative I-E measurements were performed on a single carbon nanotube attached to the two above-mentioned substrates, both showing metallic characteristics at room temperature and in air.

Study Of Sptfs/Ptfe Composite Membranes With Different Ews, Yong-Zhu Fu, Dan-Min Xing, Bao-Lian Yi, Hua-Min Zhang

Journal of Electrochemistry

In this paper, sPTFS/PTFE composite membranes for PEMFC were obtained by impregnating two kinds of sulfonated poly-α,β,β- trifluorostyrene resin with different EWs into the porous PTFE substrate membranes. Water uptake, proton conductivity, mechanical strength and fuel cell performance of these two composite membranes were measured. Water uptake and proton conductivity were greatly reduced and mechanical strength was increased by composition in comparison with homogeneous membranes. Under the operating condition: T_Cell=80 ℃, P_H2=0.2 MPa, P_O2=0.2 MPa, fuel cell performance of the two composite membranes were better than that of Nafion 115. The fuel cell performance …

Studies On The Mechanism Of Electroreduction Of Oxalic Acid, Yu-Zhan Li, Xin Liu, Rui-Sheng Hu, Deng-Ping Gu

Journal of Electrochemistry

The electroreduction mechanism of oxalic acid on Pb electrode in Na₂SO₄ solution were investigated using high scan rate cyclic voltammetry and chronoamperometry. The dynamic parameters for the first step electron transter reaction of oxalic acid electroreduction by were determined. The corresponding reduction peak potentials of oxalic acid, glyoxylic acid and glycolic acid in the cyclic voltammogranis obtained in the same condition were compared, and the intermediate reduction products of oxalic acid were suggested. The results showed that oxalic acid is weakly absorbed on the lead electrode.

Preparation, Structure And Electrochemical Hydrogenation Of Carbon Nanotubes Supported Platinum Catalysts, Qing-Gang He, Xiao-Zi Yuan, Xian-Xia Yuan, Zi-Feng Ma

Journal of Electrochemistry

In this paper, Pt/CNTs catalyst was prepared and its electrocatalytic property was studied by obtaining cycling voltammetry curves (C-V) and Tafel curves. In addition, the XRD,XPS and TEM tests were carried out to determine the structure and composition of the catalysts. It can be found that the platinum loading has been increased significantly using a carbon nanotubes support. Dispersion of Platinum was better and gave more active sites. The electrochemical characteristic of Pt/CNTs was also more desirable than that of Pt/C catalys t(Johnson Matthey). In conclusion, carbon nanotubes can played a conspicuous role in "electrogenerative" processes of PEMFC hydrogenation reactor.

Coulometric-Weighing Test Method And Its Application In Determination Of Tin Coating Mass For Electrolytic Tinplate, Xiu-Wen Dong, Yan Li, Jian-Guo Liu, Guo-Wei Lin

Journal of Electrochemistry

The coulometric-weighing test method was established and applied to determine the tin coating mass for electrolytic timplate. The effects of electric quantity, the current efficiency and the electrochemical equivalent in the coulometric test method were overcome. The inaccuracy in the determination of final point at the anodic dissolution curve in the weighing method was avoided when applied to the electrolytic timplate, higher accuracy was obtained, the SD is less than 0.04 g/m²,RSD is as small as 0.36%.

Electrochemical Character Of Water Containing Gel Electrolyte And Its Preliminary Examination In Lithium Water Cell, Jing-Dong Liu, Wen-Ji Wang, Xin-Zheng Yi

Journal of Electrochemistry

AC impedance technique has been used to characterize the system of poly(methyl acrylic acid)-poly(methyl acrylic lithiumate)-glycerol (referred to as GPE).The results showed that the conductivity of GPE increased with increasing both temperature and its water content.The glass transition temperature of GPE polymer could be lowered by water. Its conducting characteristic was just like liquid electrolyte,The electrolysis of GPE was almost the same as the electrolysis of water. Its composition voltage was about 1.50V. The GPE has been used to manufacture lithium water cell. When the graphite was used as cathode, the cell could discharge continuously for 2 hours under constant …

Cobalt Oxide Surface Chemistry: The Interaction Of Coo(1 0 0), Co3O4(1 1 0), And Co3O4(1 1 1) With Oxygen And Water, Sarah C. Petitto, Erin M. Marsh, Gregory A. Carson, Marjorie Langell

Marjorie A. Langell Publications

Cobalt oxides comprise two readily accessible cation oxidation states: Co²⁺ and Co³⁺, which are thermodynamically competitive under common ambient conditions, and redox mechanisms connecting the two states are largely responsible for their success in partial oxidation catalysis. In our studies, CoO(1 0 0), Co₃O₄(1 1 0), and Co₃O₄(1 1 1) single crystal substrates have been investigated with X-ray photoelectron spectroscopy (XPS), high-resolution electron energy loss spectroscopy (HREELS), and low energy electron diffraction (LEED) for their surface reactivity toward O₃ and H₂O and for their stability under …

Orientation And Bonding Of Biphenyldimethyldithiol, A. N. Caruso, R. Rajesh, Gordon A. Gallup, Jody G. Redepenning, Peter A. Dowben

Department of Chemistry: Faculty Publications

The molecular orbitals of 1, 1′-biphenyl-4,4′-dimethyldithiol (HS– CH₂–C₆H₄–C₆H₄–CH₂–SH) are identified from combined photoemission and inverse photoemission studies and compared with theory for several different surfaces, molecular conformations and molecular orientations. The preferential molecular orientations of biphenyldimethyldithiol, on both Au(111) and polycrystalline Co, are identified from polarization resolved photoemission studies. Two different molecular orientations are adopted by biphenyldimethyldithiol on gold depending on adsorption conditions. Biphenyldimethyldithiol is observed to bond more strongly to cobalt than gold surfaces.

Magnetoelastic Sensor For Characterizing Properties Of Thin-Film/Coatings, Leonidas G. Bachas, Gary Barrett, Craig A. Grimes, Dimitris Kouzoudis, Stephan Schmidt

Chemistry Faculty Patents

An apparatus for determining elasticity characteristics of a thin-film layer. The apparatus comprises a sensor element having a base magnetostrictive element at least one surface of which is at least partially coated with the thin-film layer. The thin-film layer may be of a variety of materials (having a synthetic and/or bio-component) in a state or form capable of being deposited, manually or otherwise, on the base element surface, such as by way of eye-dropper, melting, dripping, brushing, sputtering, spraying, etching, evaporation, dip-coating, laminating, etc. Among suitable thin-film layers for the sensor element of the invention are fluent bio-substances, thin-film deposits …

Substituted Pentacenes And Electronic Devices Made With Substituted Pentacenes, John E. Anthony, David L. Eaton, Sean Parkin

Chemistry Faculty Patents

Novel substituted pentacenes and electronic devices made with those substituted pentacenes are disclosed.

Human Glutaminyl Cyclase And Bacterial Zinc Aminopeptidase Share A Common Fold And Active Site, Rachell E. Booth, Simon C. Lovell, Stephanie A. Misquitta, Robert C. Bateman Jr.

Faculty Publications

Background: Glutaminyl cyclase (QC) forms the pyroglutamyl residue at the amino terminus of numerous secretory peptides and proteins. We previously proposed the mammalian QC has some features in common with zinc aminopeptidases. We now have generated a structural model for human QC based on the aminopeptidase fold (pdb code 1AMP) and mutated the apparent active site residues to assess their role in QC catalysis.

Results: The structural model proposed here for human QC, deposited in the protein databank as 1MOI, is supported by a variety of fold prediction programs, by the circular dichroism spectrum, and by the presence …

Extending The Oniom Integrated Mo/Mo Approach To Hydrogen Bonding In Biologic Systems: Serine-Water And Threonine-Water Dimers, Brian W. Hopkins, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

A series of two-layer ONIOM (MO:MO) methods have been systematically applied to two biologically important hydrogen-bonded dimers. Single conformations of the serine-water dimer and of the threonine-water dimer were optimized with the MP2 technique and a DZP++ basis set. The counterpoise corrected and uncorrected dissociation energies of the dimers were then computed with RHF, B3LYP, MP2, and CCSD(T) electronic structure techniques with 3-21G, 6-31+G(d), and DZP++ basis sets as well as every possible two-layer ONIOM permutation using either CCSD(T)/DZP++ or MP2/DZP++ as the high-level method. To judge the performance of each technique, the data are compared to results obtained with …

Jahn-Teller Distortions, Cation Ordering And Octahedral Tilting In Perovskites, Michael W. Lufaso, Patrick M. Woodward

Chemistry Faculty Research and Scholarship

In transition metal oxides, preferential occupation of specific d orbitals on the transition metal ion can lead to the development of a long-range ordered pattern of occupied orbitals. This phenomenon, referred to as orbital ordering, is usually observed indirectly from the cooperative Jahn-Teller distortions (CJTDs) that result as a consequence of the orbital ordering. This paper examines the interplay between orbital ordering, octahedral tilting and cation ordering in perovskites. Both ternary AMX₃ perovskites containing an active Jahn-Teller (J-T) ion on the octahedral site and quaternary A₂MM'X₆ perovskites containing a J-T ion on one-half of …

Poly(Methyl Methacrylate), Polypropylene And Polyethylene Nanocomposite Formation By Melt Blending Using Novel Polymerically-Modified Clays, Shengpei Su, David D. Jiang, Charles A. Wilkie

Chemistry Faculty Research and Publications

Two new organically-modified clays that contain an oligomeric styrene or methacrylate have been prepared and used to produce nanocomposites of poly(methyl methacryate), polypropylene and polyethylene. Intercalated nanocomposites and, in some cases, exfoliated or mixed intercalated/exfoliated nanocomposites of all of these polymers have been produced by melt blending in a Brabender mixer. The use of the styrene-containing clay permits the direct blending of the clay with polypropylene, without the usual need for maleation, to produce the nanocomposites. The systems have all been characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, cone calorimetry and the measurement of mechanical properties. These novel …

Systems-Based Design Of Bi-Ligand Inhibitors Of Oxidoreductases: Filling The Chemical Proteomic Toolbox, Daniel S. Sem, Bonnie Bertolaet, Brian Baker, Edcon Chang, Aurora Demertrina Costache, Stephen Coutts, Qing Dong, Mark Hansen, Victor Hong, Xuemei Huang, Richard M. Jack, Richard Kho, Henk Lang, Chen-Ting Ma, David Meininger, Maurizio Pellacchia, Fabrice Pierre, Hugo Villar, Lin Yu

Chemistry Faculty Research and Publications

Genomics-driven growth in the number of enzymes of unknown function has created a need for better strategies to characterize them. Since enzyme inhibitors have traditionally served this purpose, we present here an efficient systems-based inhibitor design strategy, enabled by bioinformatic and NMR structural developments. First, we parse the oxidoreductase gene family into structural subfamilies termed pharmacofamilies, which share pharmacophore features in their cofactor binding sites. Then we identify a ligand for this site and use NMR-based binding site mapping (NMR SOLVE) to determine where to extend a combinatorial library, such that diversity elements are directed into the adjacent substrate site. …

The Thermal Degradation Of Nanocomposites That Contain An Oligomeric Ammonium Cation On The Clay, Shengpei Su, Charles A. Wilkie

Chemistry Faculty Research and Publications

The thermal degradation of polystyrene, high-impact polystyrene, ABS terpolymer, poly(methyl methacrylate), polypropylene and polyethylene nanocomposites has been studied using thermogravimetric analysis coupled to Fourier transform infrared spectroscopy, TGA/FT-IR. The nanocomposites that have been studied include immiscible, intercalated and exfoliated systems and the evolved gases do not depend upon the type of nanocomposite and are qualitatively similar to those of the virgin polymer. In the case of the styrenics, the presence of clay promotes the production of oligomer, rather than monomer. It is suggested that this change in evolved products may offer an explanation for why some polymers give large reduction …

Novel Polymerically-Modified Clays Permit The Preparation Of Intercalated And Exfoliated Nanocomposites Of Styrene And Its Copolymers By Melt Blending, Shengpei Su, David D. Jiang, Charles A. Wilkie

Chemistry Faculty Research and Publications

Two new organically-modified clays have been made and used to produce nanocomposites of polystyrene, high impact polystyrene and acrylonitrile–butadiene–styrene terploymer. At a minimum, intercalated nanocomposites of all of these polymers have been produced by melt blending in a Brabender mixer and, in some cases, exfoliated nanocomposites have been obtained. The systems have all been characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, cone calorimetry and the measurement of mechanical properties. These novel new clays open new opportunities for melt blending of polymers with clays to obtain nanocomposites with important properties.

A Carbocation Substituted Clay And Its Styrene Nanocomposite, Jinguo Zhang, Charles A. Wilkie

Chemistry Faculty Research and Publications

A substituted tropylium ion can be ion-exchanged onto montmorillonite to give a novel organically-modified clay. One can prepare a polystyrene nanocomposite of this clay by emulsion, but not bulk, polymerization. This is the first example of a clay that contains a carbocation and its use to prepare a polymer-clay nanocomposite. Both the clay and its nanocomposites exhibit outstanding thermal stability. Characterization by X-ray diffraction, transmission electron microscopy, cone calorimetry, thermogravimetric analysis and the evaluation of mechanical properties shows that a mixed intercalated-exfoliated nanocomposite is obtained.

Thermochemical Properties Of Small Oxygenated Sulfur Hydrocarbons And Kinetics - Reaction Pathways Of Methylthiomethyl Radical With Oxygen, Fei Jin

Theses

The thermochemical properties on CH₃SCH₂OOH and the corresponding two radicals resulting from loss of H atom: CH₃SCH₂OO and CH₂SCH₂OOH are important to understand the stability, reaction paths and kinetics of reactions of dimethyl sulfide and other sulfur hydrocarbons (sulfides) in the atmosphere and combustion processes. Thermochemical properties for species and transition states in the methylthiomethyl radical (CH₃SCH₂) + O₂ reaction system are analyzed to evaluate reaction paths and kinetics under these conditions. Isodesmic working reaction are employed to determine the enthalpies of formation …

Comprehensive Laboratory Measurements Of Biomass-Burning Emissions: 2. First Intercomparison Of Open-Path Ftir, Ptr-Ms, And Gc-Ms/Fid/Ecd, Ted J. Christian, B. Kleiss, Robert J. Yokelson, R. Holzinger, P. J. Crutzen, Wein Min Hao, T. Shirai, Donald R. Blake

Chemistry and Biochemistry Faculty Publications

No abstract provided.

Effects Of Cisplatin On Mitochondrial Function In Jurkat Cells, Kirk Tacka, James C. Dabrowiak, Jerry Goodisman, Harvey S. Penefsky, Abdul Kader Souid

Chemistry - All Scholarship

In this work, we measured the effects of pharmacological concentrations of cisplatin (cis-diaminedichloroplatinum II) on mitochondrial function, cell viability, and DNA fragmentation in Jurkat cells. The exposure of cells to 0-25 microM cisplatin for 3 h had no immediate effect on cellular mitochondrial oxygen consumption, measured using a palladium-porphyrin oxygen sensing phosphor. Similarly, the cell viability as measured by trypan blue staining was unchanged immediately following exposure to the drug, and no small DNA fragments, characteristic of drug-induced apoptosis, appeared. At 24 h after exposure to cisplatin, cellular respiration and viability decreased relative to controls and the amount of small …

The Contribution Of Amino Acid Region Asp695-Tyr698 Of Factor V To Procofactor Activation And Factor Va Function, Daniel O. Beck, Michael A. Bukys, Lisam S. Singh, Katalin A. Szabo, Michael Kalafatis

Chemistry Faculty Publications

There is strong evidence that a functionally important cluster of amino acids is located on the COOH-terminal portion of the heavy chain of factor Va, between amino acid residues 680 and 709. To ascertain the importance of this region for cofactor activity, we have synthesized five overlapping peptides representing this amino acid stretch (10 amino acids each, HC1-HC5) and tested them for inhibition of prothrombinase assembly and function. Two peptides, HC3 (spanning amino acid region 690-699) and HC4 (containing amino acid residues 695-704), were found to be potent inhibitors of prothrombinase activity with IC(50) values of approximately 12 and approximately …

Energy Conserving Approximations To The Quantum Potential: Dynamics With Linearized Quantum Force, Sophya Garashchuk, Vitaly A. Rassolov

Faculty Publications

Solution of the Schrödinger equation within the de Broglie–Bohm formulation is based on propagation of trajectories in the presence of a nonlocal quantum potential. We present a new strategy for defining approximate quantum potentials within a restricted trial function by performing the optimal fit to the log-derivatives of the wave function density. This procedure results in the energy-conserving dynamics for a closed system. For one particular form of the trial function leading to the linear quantum force, the optimization problem is solved analytically in terms of the first and second moments of the weighted trajectory distribution. This approach gives exact …

The Melting Lines Of Model Silicon Calculated From Coexisting Solid–Liquid Phases, S. Yoo, Xiao Cheng Zeng, James R. Morris

Xiao Cheng Zeng Publications

The melting line is an important thermodynamic property of materials and can be calculated via computer simulation, given the intermolecular potential for the materials. Conventionally, the free-energy method has been mainly employed to calculate the melting line. Alternatives to the free-energy method for calculating the melting line include simulation of the solid-liquid coexistence and nonequilibrium molecular dynamics (MD) method. Recently, one of us (Morris) and Song reported a detailed simulation procedure to calculate the melting line of the Lennard-Jones system. Specifically, the MD simulation consists of a preparation run and a production run. In the preparation run, the liquid and …

Altered Phosphorylation Of [Beta]-Catenin In Glucocorticoid Treated 235-1 Rat Pituitary Tumor Cells, Susie K. Saunders

Theses, Dissertations and Capstones

Beta-catenin is an essential cell adhesion and signaling protein, associated with high prolactin levels in rat pituitary tumor cells. It has been shown that phosphorylation affects the location and activity of b-catenin. Glycogen synthase kinase (GSK3-b) is a serine-threonine kinase that phosphorylates b-catenin on N-terminal residues, targeting it for proteasomal degradation. Studies have shown that C-terminal tyrosine phosphorylation decreases the association of b-catenin with cadherin. In 235-1 rat pituitary tumor cells, our lab has shown that the glucocorticoid analog dexamethasone (Dex) decreases the half- life of b-catenin while increasing the activity of GSK3-b. The current study was undertaken to examine …

Semi-Biosynthesis Of Dna Nanostructures, Aoune Barhoumi

Theses, Dissertations and Capstones

Nanotechnology refers to all technologies aiming to build objects, make measurements, and carry out processes on the nanometer length scale. In particular molecular nanotechnology exemplifies the so-called "bottom up" approach, which is briefly defined as the ability to build useful nanostructures with molecular precision, such as molecular machinery. Such capability for controlling matter at the molecular scale has always been the dream of scientists.

All living things are nanofoundries. Billions of years ago, nature perfectly provided all living things with the most accurate biological nanotechnology systems. Cellular internal dynamics, communicative resonance in protein conformational states, viruses as microreplicators, nanoscale life …

View From The Hill, Jay Cox

Syracuse University Magazine

No abstract provided.

Synthesis Of The Novel Crown Ether 1 ,9-Dioxa-4,6-Dithiacycloundecane, Cassie Booth

Capstone Research Projects

Attempts to produce novel crowns, incorporating a thioacetal fragment, were made via two synthetic pathways. Despite the well-established reactions found in path A (see figure 3), this method failed to produce the desired crown. Path B, a one-pot reaction originally designed to close rings via the addition of a thioacetal fragment, yielded an oily product that was purified with a silica gel column (48.3% yield). Initial analysis by 1H NMR showed a structure consistent with that of the desired crown (figure 2). Mass spectroscopy was used to verify product identity, confirming the creation of our target molecule 1 ,9-dioxa-4,6-dithiacycloundecane.

Self Consistent Field, Scf Homo And Lumo For Cuo2 Layer In Cuprates, H. Sahibudeen, Juana Acrivos

Faculty Publications, Chemistry

Before photoemission studies [1995] measured the symmetry of layer cuprate conduction states along the (xy),(-x-y) direction of the unit cell, a SCF analysis [1993] gave the symmetry of the HOMO & LUMO showing O:2pxy-O:2pxy charge de-localization for the conducting CuO2 layer in a superconducting cuprate (T'-Nd2CuO4 in the crystal field of point charges of nearest neighbor unit cells). The predictive power of MO calculations are applied now to understand the concept of valence and periodic lattice distortions commonly found in these solids [2003].