Physical Sciences and Mathematics Commons^™

The Study On The Synthesis And Electrochemical Property Of K_2feo_4, Yong-Long Wang, Ning Zhou, Shi-Hai Ye, Xue-Ping Gao, Feng Wu, Zuo-Xiang Zhou, De-Ying Song

Journal of Electrochemistry

The synthesis,characterization and electrochemical property of K2FeO4 for positive materal of lithium ion battery were studied. K2FeO4 with low purity was gained through the reaction of KCIO and Fe(NO3)3 in KOH solution and after recrystalization the purity of K2FeO4 reached 97%～98%. The methods of XRD and FTIR were used to measure the structure of K2FeO4 and its initial discharge performance was tested.

Study Of Electrochemical Lithium Intercalation Performance Of Ni_(0.67)Mg_(0.33)O, Zhen-Cai Huang, Mao-Hui Chen, Guo-Tao Wu, Jin-Kua You, Zu-Geng Lin

Journal of Electrochemistry

In the present work, Ni0.67Mg0.33O and NiO were produced by sol_gel method, and characterized by XRD, a rietveld refinement and the discharge/charge test.It was found that the magnesium_doping restrained the reduction of Ni and decreased the reversible capacity for the sample of Ni0.67Mg0.33O. But the formation of the solid solution after the magnesium_doping facilitated the high dispersion of NiO, and accordingly improved the electrochemical performance.

The Preparation And Characterization Of Zno-Pani Composite Film, Yan-Yan Xi, Huai-Guo Huang, Zhi-Xin Zheng, Ping Dong, Jian-Zhang Zhou, Ling-Ling Wu, Zhong-Hua Lin

Journal of Electrochemistry

ZnO nanoparticle films were prepared on the Au film, PANI film and ITO by sol_gel method, and their morphological optical and photoelectrochemical properties were also studied. The results showed that the porous structure of PANI can suppress the aggregation of ZnO particles, resulting in the blue shift of on_set in the UV_Vis spectra and fluorescence spectra of ZnO_PANI composite film compared with that of ZnO_Au film. It was suggested that the ZnO_PANI composite film can be used in photoelectric coversion.

The Electrochemical Behavior Of Amorphous Ni-P And Ni-B Alloys In 0.5 Mol/L H_2so_4, Xu-Cheng Wang, Wei-Jiang Wang, Hou-Tian Liu, Zu-Zhan Yu

Journal of Electrochemistry

Polarization curves and impedance spectra were used to investigate the electrochemical behavior of amorphous Ni_P and Ni_B alloys in 0.5 mol/L H2SO4 solutions. The possible reason about the remarkable difference in the electrochemical behavior between amorphous Ni_P and Ni_B alloys was discussed.

An Eqcm Study Of Water Adsorption And Oxidation On Pt Electrodes In Sulfate Acid Sulotions, Heng Lin, Sheng-Pei Chen, Jin-Mei Lin, Ai-Lan Lin, Guo-Liang Chen

Journal of Electrochemistry

Simultaneous frequency and current responses during potential cycling of Pt electrode were measured in 0.1 mol·L-1 H2SO4 solution by using EQCM.Quantitative analysis of the mass change revealed that the increase of mass in the hydrogen and double_layer regions in a positive_going potential scan was due to water adsorption on the Pt electrode,further calculation indicated that water molecules adsorbed on Pt electrode in the double_layer regions through a low discharge quomodo .The EQCM studies provided quantitative results of surface mass variation during water adsorption and oxidation,and have thrown new light in elucidating the structure of double_layer between electrode and solution.

Behaviors Of Fe-Cr Alloys During Cavitation Damage, Xia Bai, Dong-Bai Sun, Hong-Ying Yu, Hui-Ming Meng, Hui-Qin Li, Zi-Shuang Fan

Journal of Electrochemistry

The influence of the surface galvanic effect on the behaviors of three Fe_Cr alloys during cavitation damage in NaCl solutions have been investigated. The results showed that the galvanic effect caused by the inhomogeneity between the undamaged surface of the alloy and the damaged one will be enhanced by the area ratio of the undamaged and the damaged.The behaviors of alloys during cavitation are closely related to both their mechanical performance and anti_corrosion capabilities.

Study On The Corrosion & Electrochemical Properties Of Alloy Aa5083 And The Effect Of Active Chlorine In Seawater, Hong-Ren Wang, Jian-Hua Wu, Jun-Tao Wang, Hong-Bin Wang, Zhi-Gang Fang

Journal of Electrochemistry

In this paper potentiodynamic technique, cyclic polarization technique and immersion corrosion method were used to study the corrosion and electrochemical properties of AA5083 alloy in quiescent seawater, the effect of active chlorine on its properties was also studied. The results obtained indicate that the active chlorine has no remarkable impact on the corrosion and electrochemical properties of AA5083 alloy in area of design concentration which range from 0.2 to 0.5 mg/L, and it has favorable influence on the improvement of pitting corrosion resistance. While the pH value of seawater has evident influence on the corrosion resistance of AA5083 alloy.

Study For The Cathodic Behavior Of Active Chlorine On 316l Ss Electrode Surface, Hui Yu, Ming-Xian Sun, Yan Ma, Xiao-Bin Wang

Journal of Electrochemistry

The cathodic reducing reactions of active chlorine on 316L SS electrode surface have been investigated by electrochemical techniques. The open circuit potential shifted positively and the limited diffusion current density increased significantly with the increasing content of active chlorine in the 3.5%sodium chloride solution. The two cathodic reduction processes of HClO and ClO- exhibited on the surface of electrode with the active chlorine added to the 3.5%sodium chloride solution and the corresponding potentials of the two reducing reactions were confirmed. The linear relationship of the mass transport_limited Faradaic current, Id vs. the square root of the angular velocity of the …

Development And Study Of The (Ag)-Ni/Cr Composite Plating With Antibacterial Properties And Corrosion Resistance, Ya-Ping Zhao, Jin-Hua Wang, Ren-He Yin, Jin Zheng, Le-Shu Yu

Journal of Electrochemistry

The 3_factor and 3_level orthogonal experiment was designed and through the comparison of the different films' antibacterial properties measured by bacterial colony counting and the corrosion resistance studied with the AC impedance method. The optimal plating conditions of the (Ag)_Ni/Cr composite plating, a novel functional plating, were determined.The results have indicated that the (Ag)_Ni/Cr composite plating is characterized by both antibacterial and corrosion resisting properties and has its wide applied prospect.

Synthesis By Complexation Processes And Characterization Of Lini_(0.8)Co_(0.2)O_2 Cathode Materials, Jing Liu, Zhao-Yin Wen, Zhong-Hua Gu, Xiu-Jian Zhu, Zu-Xiang Lin

Journal of Electrochemistry

The layered LiNi0.8Co0.2O2 compound, which has been of great interest for lithium ion batteries, was prepared at low temperatures by calcining a complex precursor at different temperatures. The physical properties of the synthesized cathode materials were discussed in the light of structural (XRD). The charge and discharge cycling of the cells containing the synthesized oxide as the positive electrode in conjunction with lithium metals and employing a non_aqueous electrolyte showed that LiNi0.8Co0.2O2 treated at 900 ℃ exhibited excellent performances. The first discharge capacity of LiNi0.8Co0.2O2 is 142 mAh/g and its capacity loss is 8%. The mechanisms of capacity degradation are …

Investigations Of Smooth Function Of Polyethylene Glycol Surfactants On The Electrolessly Deposited Silver Film, Hao Tong, Zhi-Qing Qiao, Fen-Ning Jing, Meng-Ke Li, Chun-Ming Wang

Journal of Electrochemistry

Some non_ionic surfactants of Polyethylene Glycol 2000,6000 and 20000 were used to estimate the smooth affection on the electrolessly deposited silver film. The adsorption state of the surfactants about Si/solution interface was investigated by using open circuit potential_time technology (Op_t).As comparative experiments, the atomic force microscopy (AFM) was also performed to study the surface smooth effection of the surfactants. It was found that with the increasing of the carbon chain in the surfactants, the smooth effection is getting great. PEG 20000 showed the best smooth function.

Fabrication Of Sncu_X/Cms Composite Materials For Lithium-Ion Batteries, Yu Liu, Jing-Ying Xie, Jun Yang, Ke Wang, Bao-Feng Wang

Journal of Electrochemistry

The composite material were prepared by sub_micro SnCux, particles depositing on the surface of Carbonaceous Mesophase Spherules(CMS).Electrochemical cycling tests showed that coulombic efficiency of the electrodes prepared by the composite materials was near 100 % after second cycle and the capacity dropped less than 5% after the 30th cycle, versus 390 mAhg-1 special capacity, improving 26 % special capacity of pure CMS electrode. The electrochemical performance of the composite materials is depended strongly on the alloy content in the composite, the addhesive strength between alloy particles and CMS matrix, the distribution of particles on the surface of CMS and the …

Pure Iron Electrolyzed From Scrap Iron Chips And Its Corrosion Characteristics, Wei-Min Cao, Ren-He Yin, Hui-Ceng Yan, Zhi-Qiang Ye

Journal of Electrochemistry

The high purity electrolytic iron was made from scrap iron chips. Electrolytic conditions of pure iron were determined in chloride baths and the highest purity was 99.983% by chemical analysis. Pure iron had very compact texture and high mechanical strength by SEM figures of cross section. In deaerated 0.5 kmol·m-3H2SO4 and 0.5 kmol·m-3NaCl solutions, the corrosion rate of iron decreased with increasing purity.

Fenton Reagent Produced In Electrolysis Cell And Its Using In Degradation And Decolourization Of Dye, Xi Zheng, Ri-Yao Chen, Rui-Fang Lan, Xiao Chen, Zhen Chen

Journal of Electrochemistry

The electro_chemical processing to produce Fenton reagent has been described.Fenton reagent having a high redox potential has been used as an oxidant in treatment of dye wastewater.Results show that both of the degradation and decolourization of dyes are efficient.The decolourization of dye wastewater reaches 100%.The COD removing rate is about 80%.

Electroreduction Of Cd(Ⅱ) In Dmso And Complexation Of Cd(Ⅱ) With Coumarin Derivates, Ji-Guo Song, Hua-Can Song, Qi-Qin Yang, Yi-Wen Chen, Zun-Le Xu

Journal of Electrochemistry

Cadmium p_toluenesulfonate was synthesized and tested electrochemically for the first time. This salt can lose all the hydrated water easily and the dehydrated salt do not deliquesce in the air.Hence,the cadmium p_toluenesulfonate is suitable for the electrochemical studies in organic solvents.When the Cd(Ⅱ) reduced on Pt electrode in Cd(pCH3C6H4SO3)2+TBAP+DMSO, underpotential deposition of cadmium occurred at first, and then cadmium deposited. 4_Methyl_7_hydroxylcoumarin and 3_aminocoumarin coordinate with Cd(Ⅱ) respectively, as a result the reductive potentials of Cd(Ⅱ) moved to the negative direction.

Microscopic Theory Of Network Glasses, Randall W. Hall, Peter G. Wolynes

Collected Faculty and Staff Scholarship

A theory of the glass transition of network liquids is developed using self-consistent phonon and liquid state approaches. The dynamical transition and entropy crisis characteristic of random first-order transitions are mapped as a function of the degree of bonding and density. Using a scaling relation for a soft-core model to crudely translate the densities into temperatures, theory predicts that the ratio of the dynamical transition temperature to the laboratory transition temperature rises as the degree of bonding increases, while the Kauzmann temperature falls explaining why highly coordinated liquids are “strong” while van der Waals liquids without coordination are “fragile.”

Measurement Of The Anti-Cancer Agent Gemcitabine In Human Plasma By High-Performance Liquid Chromatography, Bruce Keith, Yan Xu, Jean L. Grem

Chemistry Faculty Publications

A reversed-phase HPLC assay has been developed to determine the concentration of the anti-metabolite 2′,2′-difluorodeoxycytidine (gemcitabine, dFdC) in human plasma over the concentration range of 0.5–150 μM (0.13–39.44 μg/ml), and 2′,2′-difluorodeoxyuridine (dFdU), the deaminated, inactive metabolite, over the range of 1.0–227 μM (0.26–60 μg/ml). After the addition of 20 nmol 2′-fluorodeoxycytidine (FdC) as an internal standard, 0.5-ml samples of plasma were subjected to acetonitrile precipitation, followed by analysis using a gradient reversed-phase HPLC assay with UV detection. A Phenomenex Columbus™ C18 column, 5 μm, 150×4.6 mm, and a Waters C18, 4 μm, Nova-Pak Sentry guard column were used to achieve …

Experimental Investigation Of Steel Corrosion In Lead Bismuth Eutectic (Lbe): Characterization, Species Identification, And Chemical Reactions, John Farley, Dale L. Perry, Allen L. Johnson

Transmutation Sciences Materials (TRP)

The goal of the present research is to achieve a basic understanding of corrosion of steels by Lead Bismuth Eutectic (LBE). Liquid LBE is under consideration in the transmuter as both a spallation target and as a blanket coolant. There have been previous studies of LBE, especially by the Russians, who have over 80 reactor-years experience with LBE coolant in their Alpha-class submarine reactors. The Russians found that the presence of small amounts (ppm) of oxygen in the LBE significantly reduced corrosion. However, a fundamental understanding and verification of its role in the corrosion of steels is still very incomplete. …

Structures And Stabilities Of Small Silicon Clusters: Ab Initio Molecular-Orbital Calculations Of Si7–Si11, Xiaolei Zhu, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Ab initio all-electron molecular-orbital calculations have been carried out to study the structure and relative stability of small silicon clusters (Si_n , n=7 – 11). A number of low-energy geometric isomers are optimized at the second-order Møller–Plesset (MP2) MP2/6-31G(d) level. Harmonic vibrational analysis has been performed to assure that the optimized geometries are stable. The total energies of stable isomers are computed at the coupled-cluster single and double substitutions (including triple excitations) [CCSD(T)] CCSD(T)/6-31G(d) level. The calculated binding energies per atom at both the MP2/6-31G(d) and CCSD(T)/6-31G(d) levels agree with …

Cooperative Effects In One-Dimensional Chains Of Three-Center Hydrogen Bonding Interactions, Ruben D. Parra, Satya S. Bulusu, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Cooperative effects in a one-dimensional network of intermolecular bifurcated hydrogen bonding interactions are investigated by means of ab initio calculations. The trans–trans conformation of the diformamide molecule is used as a basic motif to model a chain of bifurcated H bonds. In this model system, the two proton–acceptor atoms belong to the same molecule. The one-dimensional network is modeled then by periodically stacking up to 12 molecules of the unit motif. Different indicators of H-bond strength such as energetic, structural, dielectric, vibrational frequencies, and isotropic chemicals shifts consistently show significant cooperative effects in the chains. The dissociation energy in the …

Particle Growth In Urban And Industrial Plumes In Texas, Charles A. Brock, Michael Trainer, Thomas B. Ryerson, J. Andrew Neuman, David D. Parrish, John S. Holloway, Dennis K. Nicks, Gregory J. Frost, Gerhard Hübler, Fred C. Fehsenfeld, J. Charles Wilson, J. Michael Reeves, Bernard G. Lafleur, Henrike Hilbert, Elliot L. Atlas, Stephen G. Donnelly Ph.D., Sue M. Schauffler, Verity R. Stroud, Christine Wiedinmyer

Chemistry Faculty Publications

Particle size distributions and gas-phase particle precursors and tracer species were measured aboard an aircraft in the plumes downwind from industrial and urban sources in the vicinity of Houston, TX during the daytime in late August and early September 2000. Plumes originating from the Parish gas-fired and coal-fired power plant, petrochemical industries along the Houston ship channel, the petrochemical facilities near the Gulf coast, and the urban center of Houston were studied. Most of the particle mass flux advected downwind of Houston came from the industries and electrical utilities at the periphery of the city rather than from sources in …

Trace Gas And Particle Emissions From Fires In Large Diameter And Belowground Biomass Fuels, Isaac T. Bertschi, Robert J. Yokelson, Darold E. Ward, R. E. Babbitt, Ronald A. Susott, Jon G. Goode, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

[1] We adopt a working definition of residual smoldering combustion (RSC) as biomass combustion that produces emissions that are not lofted by strong fire-induced convection. RSC emissions can be produced for up to several weeks after the passage of a flame front and they are mostly unaffected by flames. Fuels prone to RSC include downed logs, duff, and organic soils. Limited observations in the tropics and the boreal forest suggest that RSC is a globally significant source of emissions to the troposphere. This source was previously uncharacterized. We measured the first emission factors (EF) for RSC in a series of …

Development Of A Systems Engineering Model Of The Chemical Separations Process: Quarterly Progress Report 11/16/02- 2/15/03, Yitung Chen, Randy Clarksean, Darrell Pepper

Separations Campaign (TRP)

Two activities are proposed in this Phase I task: the development of a systems engineering model and the refinement of the Argonne code AMUSE (Argonne Model for Universal Solvent Extraction). The detailed systems engineering model is the start of an integrated approach to the analysis of the materials separations associated with the TRP Program. A second portion of the project is to streamline and improve an integral part of the overall systems model, which is the software package AMUSE. AMUSE analyzes the UREX process and other related solvent extraction processes and defines many of the process streams that are integral …

Review Of The Final Frontier, Michael F. Russo

Faculty Publications

No abstract provided.

Examination Of The Role Of The Clamp-Loader And Atp Hydrolysis In The Formation Of The Bacteriophage T4 Polymerase Holoenzyme, Michael A. Trakselis, Anthony J. Berdis, Stephen J. Benkovic

Chemistry Faculty Publications

Transient kinetic analyses further support the role of the clamp-loader in bacteriophage T4 as a catalyst which loads the clamp onto DNA through the sequential hydrolysis of two molecules of ATP before and after addition of DNA. Additional rapid-quench and pulse-chase experiments have documented this stoichiometry. The events of ATP hydrolysis have been related to the opening/closing of the clamp protein through fluorescence resonance energy transfer (FRET). In the absence of a hydrolysable form of ATP, the distance across the subunit interface of the clamp does not increase as measured by intramolecular FRET, suggesting gp45 cannot be loaded onto DNA. …

Trace Gas Emissions From The Production And Use Of Domestic Biofuels In Zambia Measured By Open-Path Fourier Transform Infrared Spectroscopy, Isaac T. Bertschi, Robert J. Yokelson, Darold E. Ward, Ted J. Christian, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

[1] Domestic biomass fuels (biofuels) were recently estimated to be the second largest source of carbon emissions from global biomass burning. Wood and charcoal provide approximately 90% and 10% of domestic energy in tropical Africa. In September 2000, we used open-path Fourier transform infrared (OP-FTIR) spectroscopy to quantify 18 of the most abundant trace gases emitted by wood and charcoal cooking fires and an earthen charcoal-making kiln in Zambia. These are the first in situ measurements of an extensive suite of trace gases emitted by tropical biofuel burning. We report emission ratios (ER) and emission factors (EF) for (in order …

Semiclassical Dynamics With Quantum Trajectories: Formulation And Comparison With The Semiclassical Initial Value Representation Propagator, Sophya Garashchuk, Vitaly A. Rassolov

Faculty Publications

We present a time-dependent semiclassical method based on quantum trajectories. Quantum-mechanical effects are described via the quantum potential computed from the wave function density approximated as a linear combination of Gaussian fitting functions. The number of the fitting functions determines the accuracy of the approximate quantum potential (AQP). One Gaussian fit reproduces time-evolution of a Gaussian wave packet in a parabolic potential. The limit of the large number of fitting Gaussians and trajectories gives the full quantum-mechanical result. The method is systematically improvable from classical to fully quantum. The fitting procedure is implemented as a gradient minimization. We also compare …

Efficient Incorporation Of Coa, Nad And Fad Into Rna By In Vitro Transcription, Faqing Huang

Faculty Publications

Protein enzymes frequently recruit small molecule coenzymes to perform a variety of biochemical reactions. While the catalytic activities of RNA have been expanding rapidly, a similar strategy for RNA to utilize coenzymes and to increase its functional capabilities has yet to be demonstrated. A general in vitro transcription procedure has been developed to efficiently prepare RNA with coenzymes CoA, NAD and FAD covalently attached to the 5' end. These adenosine-containing coenzymes initiate transcription under the T7 class II promoter by T7 RNA polymerase. In addition to the three coenzymes, other adenosine-containing molecules may be incorporated into the first nucleotide position …

Corrosion Of Steel By Lead Bismuth Eutectic: Quarterly Report November- December 2002 January 2003, John Farley

Transmutation Sciences Materials (TRP)

We continue to get valuable data from sputter depth profiling of steel samples. We meet weekly to discuss progress. We took depth-profiling data on D9 steel that had been exposed to LBE. This the first time we have examined this type of steel. This is important because it will enable us to separate out two effects and determine their effect on corrosion: composition of the steel vs surface preparation.

We started to plan a small experiments using a crucible of heated LBE, with the research program to be conducted at UNLV, on basic aspects of corrosion in this system. The …

Synthesis And Potential Antimetastatic Activity Of Monovalent And Divalent Β-D-Galactopyranosyl-(1→4)-2-Acetamido-2-Deoxy-D-Glucopyranosides, Qin Li, Bin Su, Hui Li, Xiang Bao Meng, Meng Shen Cai, Zhong Jun Li, Rou Li Zhou, Ta Lin Suo

Chemistry Faculty Publications

Anomers of monovalent and divalent β-d-galactopyranosyl-(1→4)-2-acetamido-2-deoxy-d-gluco-pyranosides were synthesized under different glycosylation conditions, and evaluated for in vitro antimetastatic activity. Three compounds showed promising inhibitory effects on cancer cell attachment, spreading, migration, and invasion. Six divalent O-β-d-galactopyranosyl-(1→4)-2-acetamido-2-deoxy-d-glucopyranosides (29–34) were synthesized and their antimetastatic activities were studied.