Physical Sciences and Mathematics Commons^™

Formation And Characterization Of Water-Repellent Nano Tio_2 Coating And Studying Its Anticorrosion Property, Guang-Xia Shen, Yi-Cong Chen, Chang-Jian Lin

Journal of Electrochemistry

Using ethyl acetoacetate (EAcAc) as a chelating agent, ultra fine TiO_2 sol is prepared. Nano-TiO_2 coatings are deposited on the 316L stainless steel by the dip-coating. Hydrothermal post-treatment leads to crack-free coatings. Meanwhile, the surface struture and properties was optimized. Self-assembly of Hetadecafluorodecyltrimethoxysilane (FSA-13) fabricates hydrophobic layers on the surface of the nano-TiO_2 coatings. Particle sizes of TiO_2 sol was analysed by zeta pals potential analysis, and surface morphology, structure and properties was characterized by contract angle instrument, XRD, and SEM technologies. The results have shown that the surface of coatings is porous, with approx. 375 nm thick, the particle …

Electrochemical Investigation Of The Dynamic Process For The Solid Supported Bilayer Lipid Membrane, Zhao Yan, Fang Yan

Journal of Electrochemistry

Three electrochemical methods,cyclic voltammetry, chronoamperometry and open-circuit potential had been used to study the dynamic process of the ITO (indium-tin oxide) conducting glass supported BLM (ITO/s-BLM) system.The results showed that the self-organization process of the membrane could be simply,visually and feasibly reflected by the three methods. Furthermore, the membrane voltage of the ITO/s-BLM system was about 0.1V when measured by open-circuit potential.

Electrochemical Study On The Anodic Process Of Fes, Hong-Hui Xu

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) H_2SO_4 + 0.5 mol·L~(-1) K_2SO_4 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 Fe~(2+) in FeS were measured. And also the activation energies of anodic reaction at different voltages was also determined.

Coulometric-Weighing Test Method And Its Application In Determination Of Tin Coating Mass For Electrolytic Tinplate, Xiu-Wen Dong

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/m~2,RSD is as small as 0.36%.

Electrodeposition Nanolaminated Growth Of Zinc, Ying Cao, Tian-Hui Shen, Jing-Yuan Yao, Gui-Fu Ding

Journal of Electrochemistry

Nanolaminated growth of the electrodeposition of zinc was studied. The structure and size of crystalline in zinc coatings were investigated by using FEG-TEM and XRD. The corrosion tests of the zinc deposition and the Coatings-Neutral salt spray test were performed, the capability in corrosion resistance of the nanolaminated growth was better than that of others.

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 …

Study Of Electrochemical Properties Of The Hydride Alloy Electrode Zrcr_(0.4)Mn_(0.2)V_(0.1)Co_(0.1)Ni_(1.2) At High Temperature, Song Li, Shi-Jun Ji, Jun-Cai Sun

Journal of Electrochemistry

Electrochemical properties of the hydride alloy electrode ZrCr_(0.4)Mn_(0.2)V_(0.1)Co_(0.1)Ni_(1.2) at the different temperature have been investigated. The results showed that the alloy electrodes possessed the maximum discharge capacities 336 mAh/g and 298 mAh/g at 25 ℃ and 70 ℃ respectively. The activation process of the alloy at 70 ℃ became faster, and the alloy reached its maximum capacity in less than 4 cycles, while in 13 cycles at 25 ℃. The high rate capability increased from 55 % at 25 ℃ to 71% at 70 ℃ at 300 mA/g. It was worth noting that the alloys at 25 ℃ and 70 …

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

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.

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 catalyst(Johnson Matthey). In conclusion, carbon nanotubes can played a conspicuous role in "electrogenerative" processes of PEMFC hydrogenation reactor.

Study On Determination Of Iodine Ion At Chitosan Modified Glassy Carbon Electrode, Bin Liu, Xiang-Ying Sun, Jin-Rui Xu

Journal of Electrochemistry

In this paper, a chitosan modified glassy carbon electrode was prepared by the method of covalent-bond reaction, and the anodic stripping voltammetric characteristics of iodine on the modified electrode was studied. The results showed that the modified electrode has higher adsorption and selectivity for I~-, and the sensitivity for I~- has been much improved in 0.1 mol·L~(-1) KH_2PO_4 solution (pH=4.0). The anodic stripping peak current of I~- on the modified electrode varied linearly with I~- concentration in the range of 2.0×10~(-6)～2.0×10~(-3) mol·L~(-1), and the detection limit reached 2.0×10~(-7) mol·L~(-1).

Electrochemical Synthesis Of Ferrate(Vi) By Anodic Oxidation, Jia-Ju Xu, Jian-Ming Wang, Wei-Hua Yang, Cheng Chen, Jian-Qing Zhang

Journal of Electrochemistry

The ferrate(Ⅵ) was synthesized by electrochemical anodic oxidation. The effects of preparation conditions on the current yield of ferrate(VI) synthesis have been studied in this work. The experimental results showed that grey cast iron as an anodic material is suitable for electrochemical synthesis and NaOH solution as an electrolyte results in a higher current yield than KOH solution. The highest current yield was obtained at a current density (4.54) mA· cm~(-2),temperature 20　℃ and 14 mol·dm~(-3) NaOH. In this case, a current yield of 68.5% was obtained by electrolysis for 1 h.

Effect Of Thiourea On Nickel Deposition, Guang-Hui Hu, Hui-Huang Wu, Fang-Zu Yang, Sheng-Lin Ical Chemistry Of Solid Surfaces Wang, University Xiamen, Xiamen Xiamen, China China

Journal of Electrochemistry

Effect of thiourea on nickel deposition at glassy carbon and nickel-deposited glass carbon electrodes was investigated with cyclic voltammograms and impetance-potential curves. It was found that the nucleation processes occurred at the glassy carbon electrode. However, this characteristics disappeared at the nicked-deposited glassy carbon electrode. It was suggested that the presence of thiourea hindered the nucleation processes, yet accelerated grain growth.Curves of impetance-potential could sensitively detect effect of thiourea on nickel depositon and reflect changes in rate-determining step with potential.

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

Chemistry Department: 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.

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 …

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.

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 …

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 …

Detection Of Trace Amounts Of Explosives And/Or Explosive Related Compounds On Various Surfaces By A New Sensing Technique/Material., L. M. Dorozhkin, V A. Nefedov, Alexander G. Sabelnikov, V G. . Sevastjanov

Alexander G Sabelnikov

No abstract provided.

Pictures From My Life With Polymer Science: Album 10, Otto Vogl

Otto Vogl

No abstract provided.

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 …

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.

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 …

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 …