Digital Commons Network^™

Electroreduction Of Holmium Ion On Iron Electrde In Molten Cholorides, Qiqin Yang, Guankun Liu, Yuzhi Su

Journal of Electrochemistry

The cyclic voltammetry, open circuit potential-time curve after poteritiostatic electrolysis, current-time curve at potential step, X-ray diffraction and electron probe microanalysiswere used to investigate the electrode process of Ho(Ⅲ) reduced on iron electrode in molten chloridesand the phases of surface alloy layer. The Ho-Fe alloys are formed at first, and then the metallic holmium is deposited when Ho(Ⅲ) is reduced on iron electrode. The charge transfer is reversible. The free energies of formation for the four inter metallic compounds of Ho-Fe system, the diffusion coefficients and diffusion activation energy of Ho in alloyed cathode are determined.

The Study Of The Growth Processes Of The Oxides On Lead Electrodes In Sulfuric Acid Solution, Hesheng Zhai, Xuguang Chen, Jinkua You, Yong Yang, Zugeng Lin

Journal of Electrochemistry

The growth processes of PbO and PbO₂ on lead electrodes have been investigatedby using in-situ methods that are combined with temporary AC resistance measurment technique and in-situ laser scanning photoelectrochemical microscopy. It is found that a linear relationship existsbetween the electrode resistance(R) and^1/2 after the electrode is oxidized at +0.6 V(vs.Hg/H₂SO₄/35% H₂SO₄) for more than 5 min. This result suggests that the growth of PbO is well distributed during the early stage of oxidation. The study by using laser scanning photoelectrochemical microscopy has further proved this point. The results also …

Application Of Voltammetry In Analysis Of Electroplating Baths, Jiayuan Xu, Shaomin Zhou

Journal of Electrochemistry

Based upon the electrochemical characteristics of the components or impurities tobe determined in the electroplating baths, and the inhibition or activation effect of the additives used on the electrodepcosition processes of metals and alloys, direct voltammetry, indirect voltammetry andvoltammetry with anodic stripping of metallic deposits, were suggested to determine the concentrationof some components, several impurities and the additives usually used in the electroplating baths. The procedure of those methtods are simple and rapid ,and are suitable to be used for in-situ control in electroplating workshops.

The Electrode Process Of Y(Ⅲ) On Copper Electrode And Its Surface Metallizing, Chungen Zhou, Shuzhen Duan

Journal of Electrochemistry

The reduction of yttrium ion on copper electrode in NaCl-KCl-YCl₃ molten saltshas been investigated. The results indicate that the formation of intermetallic compounds is occuredbefore the metallic yttrium to be formed. The formation of intermetallic compounds is controlled bythe process of which yttrium atoms are diffusing into copper electrode. The kinetic characters todiffusion of yttrium atoms were also discussed.

The Catalytic Behavior For Ni-W Electrode Modified By Carbon Ion Beam Implantion, Jishuang Zhang, Yaojiao Lv, Qinglian Li, Baoen Shen

Journal of Electrochemistry

The hydrogen evolution activity in acidic and basic mediums for Ni-W electrodemodified by carbon ion bean implantation was investigated. The experimental results show thiselectrode has superior catalytic activity for the hydrogen evolution reaction than that of the unmodified Ni-electrode. Long period testing of electrolysis under high current density show that this electrode hasalonger useful life hence it is a practical electrode material. The temperature effect of electrocatalytic property was also inverstigated. The experimental regularities are explained on the basis of the formation of surface multialloys of Ni-W-WC.

Study Of Electrochemical Properties Of Ni(Oh)2/Niooh With Spectroscopic Ellipsometry, Shengtao Zhang, Zongqing Huang

Journal of Electrochemistry

Electrochemical reactions of Ni(OH)₂ /NiOOH system were studied by using in-situ spectroscopic ellipsometry and the conventional electrochemical metheds. By fitting data from ellipsometric measurements, a transformation medel of the surface film was obtained for cathedic and anodic processes. The results indicated that the transformation medel after cobalt implantation almost remained the same as that before cobalt implantation, but the electrochemical properties were affected obviously by implantation of cobalt.

Electrocatalytic Oxidation Of Formaidehyde And Formic Acid On A Pt/SbAd Electrode, Hong Li, Lincai Jiang, Xiong Jiang

Journal of Electrochemistry

The electrocatalytic activity for the oxidation of formaldehyde and formic acid ona Sb-modified platinum (Pt/Sb_ad) was investigated. Results showed that the Pt/Sb_ad electrode was electrocatalytically more active than a Pt electrode in the anodic oxidation of formaldehyde and formicacid. In the case of formaldehyde, an oxidation peak appeared at a potential of ca. 0.7V. During the oxidation of formic acid, a 4-fold increase in the 1st peak current was observed. The Sb-modified platinum electrode was found to be most electrocatalytically active at a coverage of 0.75±0.05. The electrocatalytic activity of the Pt/Sb_ad electrode can be best …

The Device Of Wy-Ⅱ Type Cyanide Monitor And Its Applications, Xianmin Wang

Journal of Electrochemistry

A device of WY-Ⅱtype micro-computerized cyanide monitor is presented, in which the cyanide analvsis is carried out by means of microcoulomb-iodimetric with automatic following system. This instrument can be successifully employed to analyze the cyanides in industrial waste-waterfor vavious departments of chemical industry. A serious of experimental tests showed that the analytical sensitivity went up to 0.01 mg/L and the accuracy of determination was excellently coincided with that of national standard method and other methods.

The Effect Of Some Ions On Cr2O72- Anodic Formation Process At Pt And Pbo2 Electrodes, Shixiong Jin, Zhigang Zhou, Lan Wang

Journal of Electrochemistry

The influence of Ag₂SO₄, Li₂SO₄, Na₂SO₄, K₂SO₄, (NH₄)₂SO₄,MgSO₄ and KF on the evolution of O₂ and the formation of Cr₂O at Pt and PbO₂ anodes was investigated in mixed H₂SO₄-Cr₂(SO₂)₃ solutions. The kinetic data related respectively to Cr₂O formation and O₂ evolution at Pt and PbO₂ anodes were measured by method of resolving the steady-state polarization curve. The Tafel slope …

Composition Profiles In Electrodeposited Ceramic Superlattices, Jay A. Switzer, Richard J. Phillips, Teresa D. Golden

Chemistry Faculty Research & Creative Works

Superlattices in the Pb-Tl-O system with layer thicknesses in the 4-6 nm range were electrodeposited from a single aqueous solution by pulsing the applied potential during deposition. The current-time transients that resulted from the potential steps were monitored to both calculate and tailor the composition profiles of the superlattices during growth. The Cottrell method was used to determine that Tl(l) oxidation was diffusion limited at high potentials. The diffusion limitation resulted in a composition profile that was graded throughout the layer with a t^-1/2 dependence. Superlattices grown at lower potentials in which both reactants were under kinetic control had …

Conversion Of Bovine Pancreatic Phospholipase A At A Single Site Into A Competitor Of Neurotoxic Phospholipases A By Site-Directed Mutagenesis, Mu-Chin Tzeng, Chon-Ho Yen, Ming-Jhy Hseu, Cynthia M. Dupureur, Ming-Daw Tsai

Educator Preparation & Leadership Faculty Works

A 45-kDa polypeptide preferentially present in neuronal membranes was previously identified as a subunit of a binding (or receptor) protein for several phospholipase A2 variants with neurotoxicity, including crotoxin, by chemical cross-linking experiments (Yen, C.-H., and Tzeng, M.-C.(1991) Biochemistry 30, 11473-11477). The binding of crotoxin to this receptor protein was completely suppressed by sufficient F22Y, a mutated bovine pancreatic phospholipase A2 generated by site-directed mutagenesis of Phe of the wild-type enzyme to Tyr. The IC of this inhibition was estimated to be 1 μM. In sharp contrast, the wild-type enzyme gave no effect even at 50 μM. This …

A Nanosecond Ord Study Of Hemoglobin, Lawrence J. Parkhurst

Lawrence Parkhurst Publications

This year marks the one hundredth anniversary of the first observation of CO photodissociation from HbCO, with the correct interpretation and publication following in the next year (Haldane and Smith, 1896). Little of kinetic importance could be learned from this photosensitivity, however, until the development of sensitive photodetectors and short duration high intensity light sources. These allowed Gibson, in pioneering discoveries in the mid to late 1950's (Gibson, 1956, 1959), to discover “Hb*,” a rapidly reacting form of hemoglobin, which we now associate with deoxy Hb in the tertiary relaxed “r” 9 state with the protein in the quaternary R …

Observation Of Parity-Unfavored Transitions In The Nonresonant Photoionization Of Argon, B. Langer, J. Viefhaus, Oliver Hemmers, A. Menzel, R. Wehlitz, U. Becker

Environmental Studies Faculty Publications

Single-photon ionization of an atom or molecule can be subdivided into parity-favored and -unfavored transitions, the latter characterized by electron emission, preferentially perpendicular to the electric vector. The nonresonant existence of these transitions is shown experimentally and studied over an extended energy range for a variety of satellite transitions in atomic argon. The spectra exhibit several clearly resolved satellite lines with strongly negative β values close to -1, independent of the photon energy. The results confirm the corresponding predictions of angular-momentum transfer theory.

High-Brightness Beamline For X-Ray Spectroscopy At The Advanced Light Source, Rupert C. Perera, G. Jones, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goals of high energy resolution, high flux, and high brightness at the sample. When completed later this year, it will be the first ALS monochromatic hard-x-ray beamline, and its brightness will be an order-of-magnitude higher than presently available in this energy range. In addition, it will provide flux and resolution comparable to any other beamline now in operation. To achieve these goals, two technical improvements, relative to existing x-ray beamlines, were incorporated. First, a somewhat novel optical design …

Design And Performance Of The Advanced-Light-Source Double-Crystal Monochromator, G. Jones, S. Ryce, Dennis W. Lindle, B. A. Karlin, J. C. Woicik, Rupert C. Perera

Chemistry and Biochemistry Faculty Research

A new “Cowan type” double-crystal monochromator, based on the boomerang design used at National Synchrotron Light Source (NSLS) beamline X-24A, has been developed for beamline 9.3.1 at the Advanced Light Source (ALS), a windowless ultrahigh vacuum beamline covering the 1-6 keV photon-energy range. Beamline 9.3.1 is designed to simultaneously achieve the goals of high energy resolution, high flux, and high brightness at the sample. The mechanical design of the monochromator has been simplified, and recent developments in technology have been included. Measured mechanical precision of the monochromator shows significant improvement over existing designs. In tests with x-rays at NSLS beamline …

Removal Of Chlorinated Hydrocarbons From Water By Air Stripping And Solvent Sublation, Alpana Gami

Theses

Removal of trichloroethylene, monochlorobenzene and 1,3 dichlorobenzene from water by air stripping and solvent sublation into an organic phase was investigated. The sublation solvents used were paraffin oil and decyl alcohol. The rate of removal from water by solvent sublation and air stripping was highest for trichloroethylene, followed by chlorobenzene and finally 1,3 dichlorobenzene. For the three compounds, solvent sublation had the greatest advantage over air stripping in the reduction of emission of the compounds to the atmosphere. For the three compounds, the removal was enhanced at higher flowrate in both air stripping and solvent sublation. For the removal of …

Highly Enantioselective Capillary Electrophoretic Separations With Dilute Solutions Of The Macrocyclic Antibiotic Ristocetin A, Daniel W. Armstrong, Mary P. Gasper, Kimber L. Rundlett

Chemistry Faculty Research & Creative Works

Ristocetin A is one of a series of structurally related amphoteric, glycopeptide, macrocyclic antibiotics. These compounds have several features that make them attractive as chiral selectors. These include spatially oriented functional groups that are known to provide the types of interactions that are conducive to enantio-recognition, a somewhat rigid "pocket" that can provide a site for hydrophobic interactions and polar, flexible arms (i.e., pendent sugar moieties) that can rotate to hydrogen bond and otherwise interact with a variety of chiral analytes. In addition, these compounds are sufficiently soluble in water, aqueous buffers and aqueous-organic solvents that are commonly used in …

Theoretical Study Of Solvent Effects On The Electronic Coupling Element In Rigidly Linked Donor-Acceptor Systems, Robert J. Cave, Marshall D. Newton, Krishna Kumar, Matthew B. Zimmt

All HMC Faculty Publications and Research

The recently developed generalized Mulliken-Hush approach for the calculation of the electronic coupling matrix element for electron-transfer processes is applied to two rigidly linked donor-bridge-acceptor systems having dimethoxyanthracene as the donor and a dicarbomethoxycyclobutene unit as the acceptor. The dependence of the electronic coupling matrix element as a function of bridge type is examined with and without solvent molecules present. For clamp-shaped bridge structures solvent can have a dramatic effect on the electronic coupling matrix element. The behavior with variation of solvent is in good agreement with that observed experimentally for these systems.

Refinement Of The Solution Structure Of A Branched Dna Three-Way Junction, Neocles B. Leontis, Igor V. Ouporov

Chemistry Faculty Publications

We have refined the structure of the DNA Three-Way Junction complex, TWJ- TC, described in the companion paper by quantitative analysis of two 2D NOESY spectra (mixing times 60 and 200 ms) obtained in D2O solution. NOESY crosspeak intensities extracted from these spectra were used in two kinds of refinement procedure: 1) distance-restrained energy minimization (EM) and molecular dynamics (MD) and 2) full relaxation matrix back calculation refinement. The global geometry of the refined model is very similar to that of a published, preliminary model (Leontis, 1993). Two of the helical arms of the junction are stacked. These are Helix …

Synthesis, Characterization, And Molecular Structure Of Bis(Tetraphenylcyclopentdienyl)Rhodium(Ii)⊗, James E. Collins, Michael Castellani, Arnold L. Rheingold, Edward J. Miller, William E. Geiger, Anne L. Rieger, Philip H. Rieger

Chemistry Faculty Research

A 5 day diglyme reflux of Rh(acac)3 and K(C5HPh4), followed by treatment with aqueous HPF6, produces orange-yellow [(C5HPh4)2Rh]PF66 in 40 - 50% yield. Reduction of [(C5HPh4)2Rh]PF6 with sodium amalgam in THF yields olive green (C5HPh4)2Rh in 70% yield. (C5HPh4)2Rh crystallizes in the triclinic [Error : unloaded OLE object or mail attachment]space group with unit-cell parameters of a = 8.622 (3) Å, b = 10.778 (4) Å, c = 12.894 (5) Å, a = 65.58 (3)°, b = 72.66 (3)°, g = 83.52 (3)°, and Z = 1. The least squares data refined to RF = 7.63% and …

Ua35/11 Student Honors Research Bulletin, Wku Honors Program

WKU Administration Documents

The WKU Student Honors Research Bulletin is dedicated to scholarly involvement and student research. These papers are representative of work done by students from throughout the university.

• Allen, Melody. Women in Control of Courtship in As You Like It, The Merchant of Venice and All's Well That Ends Well
• Amlani, Islamshah. Electron Stimulated Desorption of Alkali Halides
• Brillhart, Kelly. Women Without Men: Hemingway's Female Characters
• Burton, Lori. Financial Statements with Environmental Concerns: An Exploratory Study of the Impact on the Auditor's Role and Responsibilities
• Combs, Vicki. Dancing the Descent: Energy and Entrophy in William Carlos Williams
• Davis, Julie. Prelude to …

A Spectroscopic Study Of A Rationally Designed Zinc Binding Protein, Jill Funk

Honors Theses, 1963-2015

Recently, biomedical science has turned its drug research endeavors towards a philosophy known as rational drug design. Its goal is to avoid the guesswork and instead design and create the exact proteins that are needed. In order for rational drug design to be feasible, a better understanding of protein structure and function needs to be obtained. This research analyses the structure and function of a "rationally" designed mutation of the calcium binding protein parvalbumin. Parvalbumin was chosen because certain aspects of its composition facilitate analysis and in addition, there is extensive data already known about the protein. The mutation involved …

Enantiomerically Enriched Α-Methyl Amino Acids. Use Of An Acyclic, Chiral Alanine-Derived Dianion With A High Diastereofacial Bias., David B. Berkowitz, Marianne K. Smith

David Berkowitz Publications

Hindered esters derived from N-benzoylalanine and the following chiral alcohols have been synthesized: (1) (−)-isopinocampheol; (2) (−)-trans-2-phenylcyclohexanol and (3) (−)-8-phenylmenthol. Sequential treatment of these esters with LDA (1.2 equiv.) and n-butyllithium (2.4 equiv.) at −78°C in THF generates the corresponding chiral dianions. Alkylation of each of these with benzyl bromide reveals that only the (−)-8-phenylmenthyl auxiliary confers a high diastereofacial bias upon its derivative dianion. In fact, that dianion (6) consistently displays diastereomeric ratios in the range of 89:11 to 94:6 for alkylations with a spectrum of nine alkyl halides. If one recrystallization step is …

Aggregation Of Chlorophyll A Probed By Resonance Light Scattering Spectroscopy, J. C. De Paula, J. H. Robblee, Robert F. Pasternack

Chemistry & Biochemistry Faculty Works

We report the resonance light scattering (RLS) spectra of chlorophyll a aggregated in a 9:1 solution of formamide and pH 6.8 phosphate buffer. The aggregate formed after 2 h of mixing, referred to as Chl(469), shows a strong scattering feature at 469 nm (Soret band) and a much weaker feature at 699 nm (Q(y) band). A kinetic investigation confirmed that the aggregation process is cooperative, and also detected one intermediate (Chl(458)) with a strong RLS spectrum but only a weak CD spectrum. We propose that aggregation proceeds via at least three steps: 1) formation of a nucleating species, probably a …

Dynamic Phenomena In Layer Superconducting Cuprate And Organic Metals, Juana Acrivos, Lei Chen, C. Burch

Faculty Publications, Chemistry

Dynamic electron spin resonance (ESR) and extended x-ray absorption edge fine structure (XAFS) measurements suggest that layered organic metals and cuprate superconductors behave similarly. The response to microwave radiation in a modulated external magnetic field indicates that: (i) triplet state, T * ESR is observed below Tc for both; (ii) the condensation of free spin doublet D to T* occurs above the transition temperature to superconductivity Tc (10 ± 1 K for the organic metal (BEDT-TTF)3Ta2F11 and 92 to 12 K for YBa2Cu3O7-δ and its rare earth derivatives); (iii) antiferomagnetic (AF) resonance is detected above Tc for the organic metal. …

The Molecular Process By Which Streptococcus Pneumoniae Activates The Immune System During Pneumococcal Infection, Brandon Abeyta

Whittier Scholars Program

This project includes a review of literature detailing the human body's defense mechanisms against Streptococcus pneumoniae. Research includes the use of a rabbit-model of the human immune system searching for a vaccine by experimenting with different portions of pneumococcal cell wall. Comprehend infection with the conclusions the cell walls are a powerful inducer of inflammatory response. Studied at Rockefeller University and learned under Dr. Elaine Tuomanen at Laboratory of Molecular Infectious Diseases.

The Analysis And Isolation Of Diarrhetic Shellfish Poisoning Toxins, Seán S. Kelly

Theses

This research was initiated to examine the Diarrhetic Shellfish Poisoning (DSP) toxin profiles in mussels (Mytilus edulis) in south-west Ireland. Extensive sampling and testing of shellfish was conducted during the toxic periods of 1991 to 1994. This was the most comprehensive study ever undertaken of toxin profiles in shellfish from a single cultivation area.

A new toxin named dinophysistoxin-2 (DTX-2), which is an isomer of okadaic acid (OA), was the major toxin during prolonged DSP episodes. This toxicity in shellfish occuired soon after high cell counts of Dinophysis acuta were observed. As well as seasonal variability in toxin levels, substantial …

Syntheses Of Cross-Linking Agents, Molecular Modeling Of Oligonucleotides And Polypeptide-Ion Complexes, Michael J. Yunes

Honors Theses

Each section of this thesis will be subdivided into three parts encompassing all of the research in which I have been involved during the past three years. These will be referred to under the headings "Syntheses:' "Molecular Modeling," and "Cross-linking Efficiencies." Each of these subdivisions may have divisions within them when necessary in order to fully detail the research.

Determination Of Hydroxyl Radical Production Rates In Natural Waters Using The Fluorometric Reagent P-Hydroxyphenylacetic Acid, Jason D. Hosmer

Honors Theses

A means of determining hydroxyl radical production rates in natural waters through the formation of a directly detectable fluorescent product has been developed. A method similar to the enzyme mediated oxidation of phydroxyphenylacetic acid by hydrogen peroxide is used (Miller and Kester, 1988). Due to the high reactivity of hydroxyl radicals, and subsequently low steady state concentrations, direct detection is very difficult. In the past detection was achieved through the introduction of a probe, usually a substituted aromatic or alcohol, that decays away at an observable rate upon reaction with hydroxyl radicals. Detection limits and accuracy of such difference based …

Volatilization Of Contaminants From Wastewater, Shaoyan Wu

Theses

Emission of volatile organic compounds (VOCs) from many industrial wastewater treatment facilities are a major source of air pollution, and getting much attention from EPA. In order to determine "Best Available Control Technology" and "Lowest Achievable Emission Rate" for controlling emissions of VOCs from industrial wastewater, the accurate estimation of VOCs emission rate and realistic modeling of contaminant volatilization are required.

In this research, the volatilization of three compounds (Toluene, Xylene, and Aniline) were studied under varying aeration, stirring, and quiescent scenarios. The concentrations of contaminant were analyzed by HPLC. Experimental rate constants were obtained by using the first order …