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Articles 11701 - 11730 of 12802

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Molecular Dynamics Simulation Of Supersaturated Vapor Nucleation In Slit Pore, K. Yasuoka, G.T. Gao, Xiao Cheng Zeng Mar 2000

Molecular Dynamics Simulation Of Supersaturated Vapor Nucleation In Slit Pore, K. Yasuoka, G.T. Gao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Molecular dynamics simulations of nucleation of Lennard-Jones vapor confined in a slit pore have been performed. The walls of the slit pore are structureless walls; each wall interacts with vapor molecules via Lennard-Jones 9–3 potential. The rate of nucleation in the steady state is determined by analyzing time evolution of the cluster size distribution. At the same vapor density and temperature, the nucleation rate in the slit pore is higher than in the homogeneous vapor [K. Yasuoka and M. Matsumoto, J. Chem. Phys. 109, 8451 (1998)], irrespective of the strength of attraction between the wall and vapor molecules. However, this …

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Cathodic Indirect Electro-Oxidation——Organic Electro-Synthesis Dimethyl Sulfone, Deng-Ping Gu, Rui-Zhi Wang, Hong-Kun Zhang, Xue-Ying Zhang, Wei Li, Bao-Qiu Cui Feb 2000

Cathodic Indirect Electro-Oxidation——Organic Electro-Synthesis Dimethyl Sulfone, Deng-Ping Gu, Rui-Zhi Wang, Hong-Kun Zhang, Xue-Ying Zhang, Wei Li, Bao-Qiu Cui

Journal of Electrochemistry

A cathodic indirect electro-oxidation system was established for indirect electro-oxidize dimethyl sulfoxide to dimethyl sulfone with electro-eduction generated H2O2 catalyzed by the pertungstate/tungstate (WO52-/WO42-) redox mediator. Influences of current density, pH, temperature, and the current efficiencies etc. On the cathodic indirect electro-oxidation of dimethyl sulfone were investigated for determining optimum reaction conditions. The current efficiency reached more than 70%. Mother-liquid could be recycled to use without pollution.

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Effect Of Different Species Of Cobalt Additive On Performance Of Nickel Hydroxide Electrode, Xian-Xia Yuan, Yin-Dong Wang, Feng Zhan Feb 2000

Effect Of Different Species Of Cobalt Additive On Performance Of Nickel Hydroxide Electrode, Xian-Xia Yuan, Yin-Dong Wang, Feng Zhan

Journal of Electrochemistry

Performances of nickel electrodes when adding or without adding Cobalt in different forms were studied, the results were interpreted by cyclic voltammetry(CV) and electrochemical impedance spectroscope (EIS). It was demonstrated that the additions of Co, CoO, CoO+Co by mechanically mixing with Ni(OH)2 all can improve the performance of nickel electrode to some extent, and when Co is added in the form of CoO the best performance can be obtained. This can be mainly attributed to the fact that three kinds of Co additives all improved the structure of nickel hydroxide and the ability of H+ in electrolyte transporting …

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Studies Of Abnormal Infrared Effects Of Nanometer Thin Films Of Transition Metals And Alloys In Acid Solutions, Shi-Gang Sun, Ming-Sen Zheng, Guo-Qiang Lu, Li-Rong Cai, Sheng-Pei Cehn, Xiao-Yin Xiao Feb 2000

Studies Of Abnormal Infrared Effects Of Nanometer Thin Films Of Transition Metals And Alloys In Acid Solutions, Shi-Gang Sun, Ming-Sen Zheng, Guo-Qiang Lu, Li-Rong Cai, Sheng-Pei Cehn, Xiao-Yin Xiao

Journal of Electrochemistry

The adsorption of CO on electrodes of nanometer thin films of transition metals (Pt, Pd, Rh, Ru) and alloys (PtPd, PtRu) prepared under cyclic voltammetric conditions has been studied by in situ FTIR spectroscopy. The abnormal infrared effects (AIREs) have been explored as a novel and general phenomenon. The AIREs consist mainly in the inversion of the direction of IR band and the significant enhancement of IR absorption by adsorbed CO species. It was revealed that the enhanced IR absoroption of adsorbed species in AIREs depends strongly on the nature of metal or alloy, and on the structure and the …

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The Study On Fabricating Thin Electrodes For Polymer Electrolyte Membrane Fuel Cells (Pemfc), Yong-Sheng Yang, Jing-Hua Liu, Chang-Peng Liu, Gong-Quan Sun, Chang-Zhi Li, Tian-Hong Lu Feb 2000

The Study On Fabricating Thin Electrodes For Polymer Electrolyte Membrane Fuel Cells (Pemfc), Yong-Sheng Yang, Jing-Hua Liu, Chang-Peng Liu, Gong-Quan Sun, Chang-Zhi Li, Tian-Hong Lu

Journal of Electrochemistry

To lower platinum loading in electrodes for polymer electrolyte membrane fuel cell, a new thin electrode fabrication technique (TEFT) was developed in this work. A series of low Pt loading electrodes with smooth and uniformed surface were fabricated by the TEFT. As a result, the maximum power density of the cell with platinum loading of 1 mg/cm2 and Nafion 117 membrane as electrolyte was up to 0.3 W.cm-2. Moreover, the effects of PTFE and Nafion content in cathodes on the performance of PEMFC with low Pt loading electrodes (1 mg Pt/cm2) were examined systematically.

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Microsystem And Electrochemistry, Zhong-Qun Tian, Jian-Jun Sun Feb 2000

Microsystem And Electrochemistry, Zhong-Qun Tian, Jian-Jun Sun

Journal of Electrochemistry

Microsystem or micro electromechanical system (MEMS) is briefly introduced. The electrochemical applications in microsystem are reviewed and prospective applications of microsystem in electrochemistry are discussed. Along with the rapid development of micro_ analytical chemical systems or lab-on-chips in 21st century, electrochemistry may play an increasingly important role in microsystem technology.

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Studies On Electrochemical Synthesis Of 4,5-Disubstituted-1,2- Benzoquinones And The Reaction Mechanism, Xian-Zhang Bu, Gui-Wu Xiao, Lin Ma, Xing-Chum He, Ling-Quan Gu Feb 2000

Studies On Electrochemical Synthesis Of 4,5-Disubstituted-1,2- Benzoquinones And The Reaction Mechanism, Xian-Zhang Bu, Gui-Wu Xiao, Lin Ma, Xing-Chum He, Ling-Quan Gu

Journal of Electrochemistry

The oxidation peak potentials (Ep) of alinine derivates and catechol in 0.1 mol/L KCl+15% alcohol solution were measured by cyclic voltammograms technique. The electrochemical oxidation condition was set according to the Ep. Three derivates of 4,5-disubstituted -1,2-benzoquinones were prepared via electrochemical oxidation-Michael addition reaction. The possible mechanism of electrochemical oxidation-Michael addition reaction is presented.

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Study On Preparation Of Coarse And Fine γ-Lialo2 Mixed Powder Used For Mcfc Matrix, Hua-Xin Lin, Bao-Lian Yi, Lian-Ying Kong, En-Jun Zhang, Li Zhou, Feng-Xia Wang Feb 2000

Study On Preparation Of Coarse And Fine γ-Lialo2 Mixed Powder Used For Mcfc Matrix, Hua-Xin Lin, Bao-Lian Yi, Lian-Ying Kong, En-Jun Zhang, Li Zhou, Feng-Xia Wang

Journal of Electrochemistry

Coarse α-LiALO2 powder was transferred completely to γ-LiAlO2 at 900 ℃ for ten hours. Fine γ-LiALO2 powder was prepared by “chloride” synthesis. MCFC matrix was fabricated by mixing the coarse and fine γ-LiALO2 powder and by tape cast. The out'put voltage of the cell assembled with the matrix was 0.85 and 0.75 V respectively at 200 and 300 mA/cm 2, and power density was about 250 mW/cm2. The performance of the matrix fabricated with the mixed powder was obviously more advanced than that of the matrix fabricated with only coarse γ-LiALO2 powder.

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An Eis Study On The Synergetic Filming Between Cathodic Protection And The Corrosion Inhibitor, Yong-Tao Zhao, Jian-Hua Wu, Jian-Hua Qian, Hui Yu Feb 2000

An Eis Study On The Synergetic Filming Between Cathodic Protection And The Corrosion Inhibitor, Yong-Tao Zhao, Jian-Hua Wu, Jian-Hua Qian, Hui Yu

Journal of Electrochemistry

The electrochemical impedance spectroscope (EIS) of 907A steel in seawater was investigated to study the film formation and destruction. The corrosion protection mechanism of the synergy interaction between cathodic protection and YKI-5 corrosion inhibitor (a mixture of polyhydric alcohol phosphate ester, phosphate and polyphosphate) is discused. Typical EIS spectral changes were clearly observed during the film formation and destruction processes. EIS results indicated that the film seemed to formed a multi-layered structure which consist of an inner layer (this may be an inhibitor-metal complex layer) and many outer layers of calcareous deposits. The film possesses of good persistency under the …

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Electro-Oxidation Of Glyoxal To Glyoxalic Acid, Yin-Sheng Chen, Xin-Sheng Zhang, Jun Hu, Ying-Chun Dai Feb 2000

Electro-Oxidation Of Glyoxal To Glyoxalic Acid, Yin-Sheng Chen, Xin-Sheng Zhang, Jun Hu, Ying-Chun Dai

Journal of Electrochemistry

An investigation has been made to obtain the glyoxalic acid by the electrochemical oxidation of glyoxal solution with hydrochloric acid under various experimental conditions.The cell used consists of a lead cathode, a DSA anode and a cation-exchange membrane of model CM001. The current efficiency and yield for glyoxalic acid generation were 80.0% and 91.1% respectively, under optimal operating conditions: velocity of electrolyte flow 1.4 m·s-1 ,current density 450 A·m-2, temperature 30～40 ℃, initial concentration of glyoxal and hydrochloric acid 9.1%～16.0%, 4%～6%, respectively.

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Studies Of The Preparation Of Electrodes From Lead Carbonate For Lead-Acid Battery Ⅱ. The Preparation Of Paste Electrodes, Zhong-Xu Dai, Di-Hua Wang, Hao-Hao Ke, Jin-Yun Zou, Yun-Hong Zhou Feb 2000

Studies Of The Preparation Of Electrodes From Lead Carbonate For Lead-Acid Battery Ⅱ. The Preparation Of Paste Electrodes, Zhong-Xu Dai, Di-Hua Wang, Hao-Hao Ke, Jin-Yun Zou, Yun-Hong Zhou

Journal of Electrochemistry

The positive and negative pastes were prepared by mixing PbCO3 and H2SO4 solution as well as relative additives, respectively. The effects of the various formation methods and the charge/discharge conditions on discharge capacity and active material utilization of both electrodes were examined. The results indicate that the performance of the positive electrode formed at 2.0 mA/cm2 is better than that formed at higher current density under the same charge/discharge condition, the PAM utilization reaches 74.4 % under discharging at 2.0 mA/cm2; and the property of the negative electrode formed by unsymmetrical square wave …

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Inhibition Of N,N'-O-Phenylen-Bis(3-Methoxysalicylidenimine) On Copper In Halide Solutions, Hou-Yi Ma, Shen-Hao Chen, Zhen-Lan Quan, Lin Niu, Shu-Lan Li Feb 2000

Inhibition Of N,N'-O-Phenylen-Bis(3-Methoxysalicylidenimine) On Copper In Halide Solutions, Hou-Yi Ma, Shen-Hao Chen, Zhen-Lan Quan, Lin Niu, Shu-Lan Li

Journal of Electrochemistry

Inhibition of N,N'-o-phenylen-bis(3-methoxysalicylidenimine) (V-o-Ph-V) on corrosion and anodic disslution of copper in neutral NaCl and NaBr solutions was investigated in terms of potentiostatic steady-state polarization and A.C. impedance techniques. The inhibition mechanism of V-o-Ph-V to copper corrosion was interpreted in detail by comparing the electrochemical behaviors of copper in halide solutions with or without V-o-Ph-V. Besides, the inhibition effect of self-assembled V-o-Ph-V film on copper corrosion in NaCl was also studied.

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Sprayed And Thermally Evaporated Carbon Films As Anodes For Lithium Ion Batteries, Shu-Gao Zhang, M.Schleich Donald Feb 2000

Sprayed And Thermally Evaporated Carbon Films As Anodes For Lithium Ion Batteries, Shu-Gao Zhang, M.Schleich Donald

Journal of Electrochemistry

Carbon films were made using spray-thermal evaporation from a kind of pyrolytic carbon powder. The films obtained with graphite structure were both potentio-statically and galvanostaically tested. Cycling patterns indicated a reduction peak on the first cycle corresponding to the formation of solid electrolyte interface, and the capacity values and x values were quite acceptable compared to theoretical ones when charging-discharging current density was suitable. Based on the experimental results, the obtained carbon films could be used as anode materials for relatively determining the electrochemical performances of cathode materials.

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In-Situ Simultaneous Esr And Conductivity Measurements For Polyaniline, Lin Zhuang, Qing Zhou, Jun-Tao Lu Feb 2000

In-Situ Simultaneous Esr And Conductivity Measurements For Polyaniline, Lin Zhuang, Qing Zhou, Jun-Tao Lu

Journal of Electrochemistry

With a new cell design, simultaneous electrochemical ESR and conductance measurements were realized for the first time. The in-situ cell consisted of a dual working electrode, a counter electrode and a reference electrode accommodated in a capillary of 1mm diameter. The dual working electrode was composed of two closely spaced Pt electrodes: a Pt disk electrode (0.5 mm diameter) sealed in a thin glass tube and a Pt layer deposited on the outside wall of the glass tube. The two working electrodes were separated by the glass gap about 20 μm thick. Two potentiostats were used to control electrode potential …

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Electrochemical Characterization Of Ir-Ta-Ti Metal Oxide Coated Titanium Anodes, Ting-Yong Wang, Li-Kun Xu, Guang-Zhang Chen Feb 2000

Electrochemical Characterization Of Ir-Ta-Ti Metal Oxide Coated Titanium Anodes, Ting-Yong Wang, Li-Kun Xu, Guang-Zhang Chen

Journal of Electrochemistry

Ir-Ta-Ti metal oxide coated titanium anodes of variable composition were prepared by thermal decomposition. Their micro morphorogies and electrochemical properties were characterized by scanning electron microscope, open circuit potential, cyclic voltammetry, consumption rate measurements and accelerated life test. The SEM results indicated that all coatings were of a porous and cracked-mud microstructure influenced greatly by the composition of coatings. The electrochemical measurements showed that the Ir-Ta-Ti ternary oxide-coated anodes exhibited excellent electrochemical activity and electrochemical stability in both acidic media and seawater which were affected by the composition and microstructure of the coatings. Owing to good corrosion resistance and low …

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Fabrication And Examination Of Reduced Temperatrue Solid Oxide Fuel Cell Using A Supported Thin Ysz Electrolyte Substrate, Yi-Huang Zhang, Yong-Lei Dong, Yi Jiang, Zhi-Gui Lu, Jing-Wang Yan Feb 2000

Fabrication And Examination Of Reduced Temperatrue Solid Oxide Fuel Cell Using A Supported Thin Ysz Electrolyte Substrate, Yi-Huang Zhang, Yong-Lei Dong, Yi Jiang, Zhi-Gui Lu, Jing-Wang Yan

Journal of Electrochemistry

By using a cost-effective wet process,dense yttria stabilized zirconia (YSZ) films on Ni-YSZ anode substrates have been prepared successfully. The YSZ film was characterized to be around 10 μm in thickness, sufficiently dense, uniform and crack free. A single solid oxide fuel cell fabricated from the supported YSZ film electrolyte on the anode substrate and a LSM cathode prepared on the YSZ film was tested. The power density reached to 0.1 W/cm2 at 800 ℃, showing a reasonable performance. Further analysis on both electrodes shows that the anodic overpotential was much larger than IR drop (including YSZ resistance and …

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Investigations Of Lithium Ion Battery Electrolyte Solution, Jing-Li Han, Qing-Guo Liu Feb 2000

Investigations Of Lithium Ion Battery Electrolyte Solution, Jing-Li Han, Qing-Guo Liu

Journal of Electrochemistry

Synthesis and electrochemical investigations of {LiB[(SO3)C6H3(O)(COO)]OC6H5} in EC/DMC or DMSO/PC mixtures are presented.

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Degradation Of N-Hexadecane And Its Metabolites By Pseudomonas Aeruginosa Under Microaerobic And Anaerobic Denitrifying Conditions, Chawala Chayabutra, Lu-Kwang Ju Feb 2000

Degradation Of N-Hexadecane And Its Metabolites By Pseudomonas Aeruginosa Under Microaerobic And Anaerobic Denitrifying Conditions, Chawala Chayabutra, Lu-Kwang Ju

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

A strategy for sequential hydrocarbon bioremediation is proposed. The initial O-2-requiring transformation is effected by aerobic resting cells, thus avoiding a high oxygen demand. The oxygenated metabolites can then be degraded even under anaerobic conditions when supplemented with a highly water-soluble alternative electron acceptor, such as nitrate. To develop the new strategy, some phenomena were studied by examining Pseudomonas aeruginosa fermentation. The effects of dissolved oxygen (DO) concentration on n-hexadecane biodegradation were investigated first. Under microaerobic conditions, the denitrification rate decreased as the DO concentration decreased, implying that the O-2-requiring reactions were rate limiting. The effects of different nitrate and …

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Observations Of Particulates Within The North Atlantic Flight Corridor: Polinat 2, September-October 1997, J. D. Paladino, Donald E. Hagen, Philip D. Whitefield, Alfred Raymond Hopkins, Otmar Schmid, M. R. Wilson, Hans Schlager, Peter Schulte Feb 2000

Observations Of Particulates Within The North Atlantic Flight Corridor: Polinat 2, September-October 1997, J. D. Paladino, Donald E. Hagen, Philip D. Whitefield, Alfred Raymond Hopkins, Otmar Schmid, M. R. Wilson, Hans Schlager, Peter Schulte

Physics Faculty Research & Creative Works

This paper discusses particulate concentration and size distribution data gathered using the University of Missouri-Rolla Mobile Aerosol Sampling System (UMR-MASS), and used to investigate the southern extent of the eastern end of the North Atlantic Flight Corridor (NAFC) during project Pollution From Aircraft Emissions in the North Atlantic Flight Corridor/Subsonic Assessment (SASS) Ozone and Nitrogen Oxide Experiment (POLINAT 2/SONEX) from September 19 to October 23, 1997. The analysis presented in this paper focuses on "the corridor effect," or enhancement of pollutants by jet aircraft combustion events. To investigate the phenomena, both vertical and horizontal profiles of the corridor, and regions …

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Double Cysteine Mutations In Staphylococcal Nuclease: The Effect Of Artificially Introduced Disulfide Bonds On Protein Structure And Stability, Anna Terry Jan 2000

Double Cysteine Mutations In Staphylococcal Nuclease: The Effect Of Artificially Introduced Disulfide Bonds On Protein Structure And Stability, Anna Terry

Inquiry: The University of Arkansas Undergraduate Research Journal

Since a protein's function depends on its structure, basic research in protein structure facilitates the solution of many practical problems, such as the synthesis of more effective medicines. With this larger goal in sight, the purpose of this research project is to understand better the chemical principles that underlie protein structure and stability. Disulfide bonds are a potentially stabilizing feature of many proteins. They may form between cysteine residues in close proximity to one another if the orientation is favorable. Often found in proteins produced by organisms that grow at high temperatures, disulfide bonds may anchor side chains together, making …

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Spin-Exchange Term In The Solvent Equation Of State Near The Critical Point For Electron Transfer Reactions, Juana Vivó Acrivos Jan 2000

Spin-Exchange Term In The Solvent Equation Of State Near The Critical Point For Electron Transfer Reactions, Juana Vivó Acrivos

Faculty Publications, Chemistry

Phenomenological Equations of State (EOS) for fluids near their critical point have been obtained using literature compression factor data, Zc = Pc Vc/(n R Tc) = 0.40 to 0.10 in Table I (Pc, Vc/n, Tc are the pressure, volume per n mole, and the absolute temperature of the fluid at the critical point). The objective is to explain the deviations from the van der Waals value, Zc(vdW) = 3/8 (-70 % for molten Se and alkali metals up to 6 % for molten Pb, Hg, and In) by including in the commonly used phenomenological thermodynamic relations a term which explicitly …

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Studies Of Tryptophans In Membrane- Spanning "Walp" Peptides By Deuterium Nmr Spectroscopy, Nichole Reed Jan 2000

Studies Of Tryptophans In Membrane- Spanning "Walp" Peptides By Deuterium Nmr Spectroscopy, Nichole Reed

Inquiry: The University of Arkansas Undergraduate Research Journal

WALP pep tides of sequence acetyl-Gly-Trp-Trp-(Leu-Ala)-Trp-Trp-Ala-ethanolamine insert into lipid bilayers as membrane-spanning a-helices and modulate the lipid phase behavior as functions of n and the lipid acyl chain length. A key feature of the WALP peptides is the positioning of tryptophan (Trp) indole rings at the membrane/water interface. For the examples WALP19 with n = 6.5 and WALP23 with n = 8.5, we have labeled individual indoles with deuterium and incorporated the labeled peptides in oriented, hydrated bilayers of Dimyristoyl-phosphatidylcholine (DMPC). Deuterium NMR spectra from these samples show sharp resonances when the membrane normal is aligned either parallel (Beta = …

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Versatile Apparatus For Measuring Kinetics Of Gaseous Reactions By A Relative Method, Edmond W. Wilson Jr., Holly A. Sawyer, Amber A. Sawyer Jan 2000

Versatile Apparatus For Measuring Kinetics Of Gaseous Reactions By A Relative Method, Edmond W. Wilson Jr., Holly A. Sawyer, Amber A. Sawyer

Journal of the Arkansas Academy of Science

It is important that accurate, reproducible values for the rates of chemical reactions occurring in the atmosphere be obtained. The value of accurate kinetics measurements is to improve the accuracy of mathematical models used to forecast the state of the atmosphere. We describe a versatile, robust apparatus for obtaining atmospheric reaction rate values and their temperature dependencies by a relative method. This relative method has the advantage over absolute methods in that errors due to impurities and adsorption on walls of the reaction apparatus are minimized. In addition, relative values serve as an important verification for absolute values. The apparatus …

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A Computational Approach To Determining Stability Constants For Transition Metal Ion Complexes, Jason St. Clair Jan 2000

A Computational Approach To Determining Stability Constants For Transition Metal Ion Complexes, Jason St. Clair

Honors Theses

The complexation of metal ions in natural waters plays a critical role in defining the metal's biogeochemistry, Numerous investigators have used various experimental techniques to measure complexation constants in the laboratory, but many constants are still poorly undefined or have yet to be investigated due to the difficulty of some of the experiments. A computational approach to obtaining these constants for complexes of Fe(lII), Fe(D), Cr(lli), Cu(lI), Zn(II), and Cd(II) was explored with varying degrees of success. Calculated Gibbs Free Energies were compared to experimental stability constants. Calculations were performed using Spartan's DFT package at the pEP level and with …

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The Effects Of Argon Dilution On Hydrogenated Amorphous Silicon Prepared By D.C. Plasma Glow Discharge : Optical And Infrared Spectroscopic Studies, Aniszawati Azis Jan 2000

The Effects Of Argon Dilution On Hydrogenated Amorphous Silicon Prepared By D.C. Plasma Glow Discharge : Optical And Infrared Spectroscopic Studies, Aniszawati Azis

Student Works (2000-2009)

Hydrogenated amorphous silicon (a-Si :H) films were prepared from the discharge of pure silane and silane diluted in argon using a home-built hori zontal direct current(d.c.) plasma glow discharge system. The effects of argon dilution of silane on the optical properties, chemical bonding properties, hydrogen content and microstructure parameter of the films produced were studied and analyzed. Film thickness, refractive index, optical energy gap and the Urbach tail bandwidth were obtained from the optical transmission spectra of the films while the H content and the microstructure parameter were derived from the Fourier Transform infra-red(FTIR) spectra of the films. The FTIR …

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Electrodeposition Of Copper On Polished Copper Electrode, Jia Tsung Ling Jan 2000

Electrodeposition Of Copper On Polished Copper Electrode, Jia Tsung Ling

Student Works (2000-2009)

This project studies the surface morphology of the copper deposit from three different bath solutions on polished copper (3.1 mm in diameter) electrode by using Scanning Electron Microscopy. The behaviour of glycine as an additive in a bath solution containing 0.3 M of copper (II) sulphate and 2.2 M of sulphuric acid was studied by using cyclic voltammetry. In this project, glycine did not involved directly in the reaction of CU²⁺/CU couple but increased the potential and current density of the plating process. However, glycine has the properties for inhibiting the deposition of copper onto the copper disc. Moreover, block …

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Infrared Spectoscopy And Electrical Conductivity Of Copper(Ii) 4-Aminobenzoate And Iondine-Doped Copper(Ii) 4-Aminobenzoate, Chang Fu Dee Jan 2000

Infrared Spectoscopy And Electrical Conductivity Of Copper(Ii) 4-Aminobenzoate And Iondine-Doped Copper(Ii) 4-Aminobenzoate, Chang Fu Dee

Student Works (2000-2009)

Copper(II) 4-aminobenzoate (CAB), prepared from copper(II) acetate monohydrate and 4-aminobenzoic acid, was a dark green powder. Fourier Transfonn lnfrared (FTIR) spectrum of CAB, recorded as KBr disc, indicated the presence of all bonds and functional groups expected of it, and the absence of hydrogen bonding. Its conductivity at room temperature was 4.2 x 10^-11 Scm^·1. The value increased as temperature decreased indicating metallic behaviour. Density of states at Fenni level, hopping distance, hopping energy and density of charge carriers calculated based on Mon's Variable Range Hopping model (VRH) are 2.65x 10^-22 (eV)^-1 cm^-3, 7.47 x 10^-8 cm, 0.02 eV and …

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Investigations On The Conductivity Of Organotin-Doped Polyethyleneoxide Polymer System, Lekshmi Sarojiniamma Jan 2000

Investigations On The Conductivity Of Organotin-Doped Polyethyleneoxide Polymer System, Lekshmi Sarojiniamma

Student Works (2000-2009)

Poly(ethylene oxide) (PEO) has been doped with selected organotin compounds. The organotin dopants used were triphenyltin thiocyanate (Ph3SnSCN) and tetramethylammonium dichlorotriphenylstannate [Ph3SnClr[Me4N)•. Tin incorporation in the polymers was established by several physical techniques. The infrared spectroscopic analysis of the Pb3SnSCN - doped electrolyte film showed bands at 2080-2050 cm.·' which are also given by pure Ph3SnSCN. Different concentrations of organotin doped electrolytes were prepared and conductivity studies on these were perfonned using impedance spectroscopy. From the measurements it was found that the best conductivity of 7.6xJ0.g Siem was obtained for the composition with PEO :dopant ratio of90:10 at room temperature. …

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Theories Of The Origin And Early Evolution Of Life, David A. Dewitt Jan 2000

Theories Of The Origin And Early Evolution Of Life, David A. Dewitt

Faculty Publications and Presentations

After the theory of spontaneous generation was discredited, only religious explanations were offered to explain the origin of life. Alexander Oparin (1894-1980), an atheist, suggested that natural chemical reactions produced biological molecules that came together to form the first living thing. Later, Stanley Miller tested this hypothesis and produced chemical "building blocks" but not life itself. In spite of much progress, there is still no clear consensus on how life originated on Earth. Some scientists are even looking to outer space for the origin of life.

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Heavy Metal Removal From Aquatic Systems By Northern Anatolian Smectites, Çi̇ğdem Arpa, Ridvan Say, Nuray Şatiroğlu, Sema Bektaş, Yuda Yürüm, Ömer Genç Jan 2000

Heavy Metal Removal From Aquatic Systems By Northern Anatolian Smectites, Çi̇ğdem Arpa, Ridvan Say, Nuray Şatiroğlu, Sema Bektaş, Yuda Yürüm, Ömer Genç

Turkish Journal of Chemistry

Competitive adsorption of the heavy metal ions Cu(II), Cd(II) and Pb(II) from aqueous media onto northern Anatolian smectites with a mean particle diameter of 200 $\mu$m, was investigated. The adsorption rate and capacity of the smectite for the selected heavy metal ions, containing different amounts of these ions (5-900 mg/L) at values ranging from pH 1.0 to 7.0 were studied. Very high adsorptions rates were observed at the beginning, and adsorption equilibria were then gradually achieved in about 30 minutes. The maximum adsorption of metal ions onto the smectite were found to be 41.46 mg Cd(II), 36.11 mg Pb(II) and …

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