Physical Sciences and Mathematics Commons^™

The Lineal Polarization Method For Corrosion Rate Measurement Of Reinforcing Bar Of Concrete In Situ, Ai-Ling Du, Wen-Tao Hou, He-Ming Zhang, Jian-Qun Luo

Journal of Electrochemistry

A linear polarization method was applied to measure corrosion rate of reinforcing bar of concrete in situ. Generally in the experiment, the area and shape of the reinforcing bar as a working electrode can be changed and adjusted according to our needs. But polarization area cannot be defined when reinforcing bar is polarized in situ, so that a real R p can't be obtained. Thus the purpose of present work is to improve the measurement system. We used the double_ring auxiliary electrodes made by ourselves. The size of the double_ring auxiliary electrodes was adjusted repeatedly until the real polarization area …

A New Method For The Preparation Of The Electrodes With Very Low Platinum Loading Used In Proton Exchange Membrane Fuel Cell, Zhi-Gang Shao, Bao-Lian Yi, Ming Qiao Ya-Guang Han, Hao Liu, Jing-Rong Yu

Journal of Electrochemistry

Research and development on low platinum loading electrode is very important in reducing the cost of proton exchange membrane fuel cell(PEMFC)stack.This paper has put forward a new method to prepare the electrode of PEMFC. The pore forming substances were used in this methd. The low platinum loading electrodes (0.02 mgPtcm -2 )have already been prepared with the method. Compared with the traditional method, the new method is simple, cheep, and easy to scale up. The superior composition of the electrodes is catalyst: pore forming substance: Nafion= 331. The performance of a single cell using this kind of electrodes and Nafion …

Cathodic Indirect Oxidation Of Organic Compounds(Ⅱ)——Cathodic Indirect Epoxidation Of Olefine, Xue Ying Zhang, Bao Qiu Cui, Deng Ping Gu, Wei Li

Journal of Electrochemistry

We described a novel cathodic indirect epoxidation system in which O 2 was first cathodically reduced to H 2O 2. Then VO(acac) 2 was oxidized by H 2O 2 homogeneously to VO(acac) 2OOH which was used to epoxidize some olefine such as maleic, fumaric and crotonic acids. Many affecting factors on the current efficiency were optimized. The research will contribute to the developments of organic electrosynthesis.

The Electro-Catalytic Oxidation Of Hcooh On Electrodeposited Pd Electrode, Quan Zhou, Cunzhong Zhang, Xiaolin Lu, Zhongda Wu

Journal of Electrochemistry

The coherent electroplates were prepared by electro depositing Pd on supporting materials glassy carbon. The surface morphology of the electrodes was examined by SEM. The electro oxidation of HCOOH in HClO 4 solution was investigated by using cyclic voltammetry. The results show that the deposited conditions in the preparation of electrodes by electro depositing Pd affect the electrodes electro catalytic activity to the oxidation of HCOOH. The platinized Pd electrode on GC substrates using large current density is of higher catalytic activity to the oxidation of HCOOH than Pd electrode. The electro catalytic activity of PdO formed on the Pd …

Electrochemical Evaluation On The Porosity Of Electroless Ni-P Alloy Coatings, Hong-Ying Yu, Dong-Bai Sun, Jing-Bing Huang, De-Jun Yang

Journal of Electrochemistry

By investigating the polarization curves of pure Ni P alloy,Ni P alloy coation and carbon steel in nitric acids with different concentrations,the sutable concentration of nitric acid for the evaluation of the porosity of Ni P alloy coatings has been determined and the coatings with different thickness have been evaluated.The results indicated that the nitric acid with 10 wt% concentration is the most suitable solution for the porosity of the coating by using electrochemical method.The polarization curve of Ni P alloy coating in 10% nitric acid can accurately reveal the porosity.With the decrease of the porosity of the coating,the corrosion …

Pulse Potential Modulated Electrochemical Gas Sensors, Zhong Bai Zhou, Liang Dong Feng, Wen Jun Liu

Journal of Electrochemistry

The current popular electrochemical gas sensors are mostly stable with regard to their operating states. As a result, the further improvement of sensor charcateristics is restricted by such a "steady state" . Based on the transient electrochemistry principle, a kind of all new transient electrochemical multi component gas sensors— "pulse potential modulated electrochemical gas sensors" was established by combining computer controlled fast modulated potential technique with microelectrode method.This novel approach provided a real time and dynamic sensor technique integrated with acquisition, treatment and display of signals for rapid simultaneous detecion of multicomponent gases, as illustrated by the case of monitoring …

The Study On Lithiated Titanium Composite Oxides As Negative Electrode For Lithium-Ion Battery, Xiao-Yan Yang, Shou-Nan Hua, Shu-Yong Zhang

Journal of Electrochemistry

Lithiated titanium composite oxides Li 4Ti 5O 12 were prepared from Li 2CO 3 and TiO 2. The XRD results of this composite oxides indicated that the compound had a spinel structure. The electrochemical behavior of lithiated titanium composite oxides was examined. The results showed that this material had an excellent cyclic capability and reversibility for lithium insertion, and had high specific capacity: the initial discharge capacity was 300 mAh·g -1 , and the reversible capacity was 100 mAh·g -1 . The discharge plateau (about 1.5 V) and the charge plateau (about 1.6 V) were very close on the voltage …

Studies Of The Lial_Yni_(1-Y)O_2 As Cathode Materials For Rechargeable Lithium Ion Batteries, Xiao-Gan Li, Wei-Hua Qiu, Chuan-Gang Lin, Qing-Guo Liu

Journal of Electrochemistry

In this paper, we have synthesized series of single_phase LiAl yNi 1-y O 2 (differentive in value_y) by solid reaction. Through examining their electrothemical properties, found that, under a proper sintering condition, Li xAl 0.25 Ni 0.75 O 2 solution for cathode materials of rechargeable lithium ion batteries showed more pleasing properties in overcharge_resist and cycling life ( vs LiNiO 2). When x>1, the capacity can be kept 125mAh/g after 30 cycles under higher charged/discharged voltages ranging from 3.0 V to 4.8 V, whereas that of pure LiNiO 2 has only 61 nAh/g after 25 cycles. The results of …

Electrochemical Characteristics Of Sb Irreversibly Adsorbed On Pt(100), Pt(110), Pt(111) And Pt(320) Electrodes, Yi Yun Yang, Zhi You Zhou, Qi Hui Wu, Shi Gang Sun

Journal of Electrochemistry

The electrochemical behaviors of irreversibly adsorbed antimony on Pt(100), Pt(110), Pt(111) and Pt(320) were studied by using cyclic voltammetry. The results revealeds that the Sb adatoms are stable on Pt(100), Pt(110), Pt(111) and on Pt(320) when electrode potentials are below 0.45 V(SCE) and 0.40 V, respectively. It was demonstrated that various coverages of Sb ad can be conveniently obtained by controlling the number of potential cycling and varying the upper limit of potential scan. The electrochemical behaviors of irreversibly adsorbed antimony varied with the surface atomic arrangement of Pt single crystal electrodes. Based on quantitative results of the relationship between …

A Study On Stochastic Resonance For The Process Of Active-Passive Transition Of Iron In Sulfuric Acid, Hong Bo Ding, Bao Yun Xia, Chun Sheng Yin, Zhong Xiao Pan

Journal of Electrochemistry

The bistable characteristics of the process of active passive transition of iron in sulfuric acid was described and the stochastic resonance phenomenon in the process was simulated.

Corrosion Behavior Of Reinforcing Steel In Concrete, Rong Du, Gui Gui, Rong Hu, Feng Zu Gang, Tan Jian De, Lin Chang Guang, Jian Jian

Journal of Electrochemistry

The corrosion behavior of reinforcing steel in concrete in chloride free and chloride contaminated simulated concrete solutions was studied by electrochemical technique.The results showed that the reinforcing steel exhitibted different corrosion characteristics in the different solutons.In general ,the steel in concrete was protected in the test solutions with no salt or the lower concentration of NaCl.When the concentration of NaCl is larger than 70%,however,the corrosion behavior of the steel varied considerably,and the corrosion rate increased as pH fell and the concentration of Cl - increased.

Synthesis Of Li_(1+X)Mn_2o_4 Cathode Material For Lithium-Ion Batteries With Solution Method, Pei Song Liu, Sing Quarn Liu, Qing Li, Zhao Yong Chen, Bai Lan Zhang, Zuo Long Yu

Journal of Electrochemistry

The cathode materials Li 1+x Mn 2O 4 were prepared with citric acid complexing and solution impregnating methods.Structure characterization and specific surface area test were performed by means of XRD,BET methods ,the influences of calcination temperature,Li/Mn molar ratio and raw materials on the structure and electrochemical capacity of samples have beem examined.The results showed that the Li/Mn molar ratio and calcimation temperature were the key factors affecting the electrochemical capacity of cathode materias.The optimum conditions for synthesis of Li 1+x Mn 2O 4 cathode material were 0≤x≤0.05 and calcined at 750°C.The initial capacity of the sample reached 120 mAh/g and …

Three-Dimensional Microfabrication On Gaas Using A Regular Patterns Mold, Hai-Gou Huang, Jian-Jun Sun, Xiong-Ying Ye, Li-Min Jiang, Jin Luo, Ze-Sheng Lu, Shen Dong, Zhong-Qun Tian, Zhao_Ying Zhou, Zhao_Wu Tian

Journal of Electrochemistry

Electrochemical etching of single crystal GaAs (111) was performed with a regular mold which resembles the micro_gear patterns. The etched patterns on GaAs was very consistent with the negative copies of the mold when the confined etchant layer technique (CELT) was used. However when the scavenger chemical of H 3AsO 3 was not added in the etching solution, the regular micro_gear patterns of the mold could not be obtained. In addition ,the procedure of fabricating a electrochemical mold is introduced and the characteristics of the mold are briefly discussed.

The Effect Of Cerium On The Anodic Behavior Of Pb-Ca-Sn Alloy In Sulfuric Acid Solution, Hou Tian Liu, Jiong Yang, Hai He Liang, Ji-Hua Zhuang, Wei-Fang Zhou

Journal of Electrochemistry

The cyclic voltammograms for Pb - 0.5 at% Ca - 1.5 at% Sn and Pb - 0.5 at% Ca - 1.5 at% Sn containing a certain amount of cerium in 4.5 mol·dm -3 H 2SO 4 at 20℃ were measured between 0.6 V and 1.4 V(vs. Hg/Hg 2SO 4). The growth rate of the anodic Pb(Ⅱ) films formed on the mentioned alloy electrodes at 0.9 V in the same sulfuric acid medium was investigated using the Linear Sweep Voltammetry. The variation with electrode potential of the real part of the impedence (Z’) for the anodic Pb(Ⅱ) films was measured using …

A Study On The Cylindrical Zinc-Air Battery, Sheng Sian Li, Gui Mao Zhou, Xin Ping Ai, Han Xi Yang

Journal of Electrochemistry

The zinc air battery has advantages of high specific energies and low cost,therefore attracts much interests.However,its application is limited only in prismatic and button type.This paper reported a novel design of cylindrical zinc air batteries and the performances of the batteries tested at various conditions.The results showed that when discharged at the current of 40 mA at 20 °C, the capacity of AA size and AAA size batteries reached 4000mAh and 1400mAh respectively,corresponding to the energy densities 280 Wh/kg and 200 Wh/kg.The effects of the discharge current, temperature and humidity on the performances of the batteries are also discussed.

Oxidation Of [(Cyclic Triamine)(1,5-Cyclooctadiene)Iridium]+ Cations By Hydrogen Peroxide Forms Metallaoxetanes, Thomas C. Flood, Masanori Iimura, Jeremy M. Perotti, Arnold L. Rheingold, Thomas E. Concolino

Chemistry and Physics Faculty Articles

Iridaoxetane 3 formed by oxidation of 1 with aqueous H₂O₂ is isolated and characterized, providing a rare example of formation of a metallaoxetane by direct oxidation of a metal–alkene complex.

The Development Of A Lutetium Recovery Plant, Peter Michael Smith

Doctoral Dissertations

This research project focused on the scale-up of an industrial facility for the continuous counter-current solvent extraction (CCCSX) separation of lutetium. CCCSX involves a multistage apparatus for the mixing in each stage of two immiscible liquid phases to transfer an analyte from one phase to the other. The two phases continuously flow in opposite directions in a CCCSX system. In this research, aqueous lutetium solutions, obtained from the acid leaching of lutetium oxyorthosilicate, were mixed with kerosene solutions of phosphorus based metal extractants (e.g. mono-2-ethylhexyl-(2- ethylhexyl) phosphonic acid, MEHEHP). This system extracted the lutetium from the aqueous phase, transferring the …

9. Oskar Friedrich Olaj, Otto Vogl

Otto Vogl

No abstract provided.

Reaction Of Caffeic Acid With Amino Acids, Yonggang Wang

Masters Theses

The reaction of caffeic acid with tryptophan was studied as a model for the reaction of caffeic acid with amino acids in the aquatic environment. Although the autoxidation reaction of caffeic acid in aqueous solution with subsequent dimerization had been previously studied, it was examined as well for comparison purposes. The present studies demonstrate that oxidized caffeic acid would react with tryptophan. The reaction, like the dimerization reaction, was catalyzed by the presence of iron(III) ions at low pH ( <4) and by hydroxide ions at high pH (10). The reaction of caffeic acid with itself yielded six products, four of which were identified by mass spectroscopy as dimers, with the other two being trimers. The reaction of caffeic acid with tryptophan yielded three product peaks. Two of the product peaks had similar retention times to the dimers from the self-reaction of caffeic acid; the third was a new product resulting from the reaction of caffeic acid with the tryptophan.

A mechanism for the reaction of caffeic acid with tryptophan has been proposed. This mechanism was based on the analysis …

Cyclodextrin Inclusion Complexes Of Betamethasone-Related Steroids Studied Using Hplc, Keith Gerald Flood

Seton Hall University Dissertations and Theses (ETDs)

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Reaction Of Tricarbonyl(Dienal)Iron Complexes With B-Allyldiisopinocampheylborane, Vadapalli Prahlad, Abdel-Aziz S. El-Ahl, William Donaldson

Chemistry Faculty Research and Publications

Addition of allyldiisopinocampheylborane to racemic (dienal)iron complexes, followed by oxidation, affords diastereomeric (1,4,6-trien-3-ol)iron complexes with moderate to low enantioselectivity. The high enantioselectivity typically observed for this allylborane reagent is attenuated by steric interaction between the Fe(CO)₃ group and the chiral isopinocampheyl groups. Further diminution of the enantioselectivity is observed for dienal complexes in which one rotomer predominates.

Kinetic Studies On The Reaction Of Hydroxyl Radicals With Aromatic Compounds, Paul Chadwick

Masters

No abstract provided

High Efficiency Separation Of Microbial Aggregates Using Capillary Electrophoresis, J. M. Schneiderheinze, Daniel W. Armstrong, G. Schulte, David J. Westenberg

Chemistry Faculty Research & Creative Works

Recent advances in the technique of capillary electrophoresis have demonstrated fast, highly efficient separation of mixtures of intact microbes. This paper describes the application of this technique for the separation of microbial aggregates of Micrococcus luteus, Saccharomyces cerevisiae, or Alcaligenes faecalis. The aggregates of these microbes were resolved into several highly efficient peaks with analysis times under 10 min and efficiencies approaching 1 000 000 plates m-1 in some cases. A reproducible relationship was found between the electrophoretic mobility and the aggregation number or size of the cluster under a given set of experimental conditions. Often, cellular aggregation was reversible …

Photophysical Study Of Linked 1,4,7-Triazacyclonane Cr (Iii) Complexes, Weizhen Tu

Masters Theses

A series of mono and bimetallic Cr(III) complexes based on the 1,4,7- triazacyclonoane(TACN) were prepared. Complexes of the Cr(TACN)X₃ , and Cr₂(DTNE)X₆ demonstrated marked difference of photophysical properties on the nature of X. In cases where X is more easily oxidized, enhanced extinction coefficient in the ⁴A₂ ➔ ²T, absorption and larger quantum yield of emission at 77K were observed in the dimer complexes. Shorter lifetime and enhanced decay rate were also found in the dimer complexes suggests that there might exists weak coupling behavior between the two Cr(III) metal cents in the …

Observation Of Stratospheric Ozone Depletion Associated With Delta Ii Rocket Emissions, Martin N. Ross, Darin W. Toohey, W. T. Rawlins, E. C. Richard, K. K. Kelly, A. F. Tuck, M. H. Proffitt, Donald E. Hagen, Alfred R. Hopkins, Philip D. Whitefield, J. R. Benbrook, W. R. Sheldon

Physics Faculty Research & Creative Works

Ozone, chlorine monoxide, methane, and submicron particulate concentrations were measured in the stratospheric plume wake of a Delta II rocket powered by a combination of solid (NH₄ClO₄/Al) and liquid (LOX/kerosene) propulsion systems. We apply a simple kinetics model describing the main features of gas-phase chlorine reactions in solid propellant exhaust plumes to derive the abundance of total reactive chlorine in the plume and estimate the associated cumulative ozone loss. Measured ozone loss during two plume encounters (12 and 39 minutes after launch) exceeded the estimate by about a factor of about two. Insofar as only the …

Design And Characterization Of A Synthetic Electron-Transfer Protein, Anna Y. Kornilova, James F. Wishart, Wenzhong Xiao, Robin C. Lasey, Anna Fedorova, Yeon-Kyun Shin, Michael Y. Ogawa

Chemistry Faculty Publications

A 30-residue polypeptide [H21(30-mer)] with the sequence Ac-K(IEALEGK)(2)(IEALEHK)-(IEALEGK)G-NH2 was synthesized. The circular dichroism (CD) spectrum of the peptide shows minima at 208 and 222 nm and theta(222)/theta(208) = 1.06, which indicates the formation of a self-assembled coiled-coil when dissolved in aqueous solution. The concentration dependence of the CD data can be fit to an expression that describes a two-state monomer-dimer equilibrium for the apopeptide (K-d = 1.5 +/- 0.4 mu M and theta(max) = -23 800 +/- 130 deg cm(2) dmol(-1)), showing that it has a maximum helicity of 69%. A [MTSL-C21(30-mer)] dimer was also prepared in which MTSL is …

Studies Of Sulfur Reduction Of Taurine And Taurine-Conjugated Bile Acids By Bile Acid 7Α-Dehydroxylating Bacteria, Jiang Qian

Masters Theses & Specialist Projects

Bile acids are C24 steroids that are derived in the liver from cholesterol and secreted into the intestinal lumen to aid in emulsification of dietary lipids and lipid-soluble vitamins. The indigenous intestinal microflora modify bile acids, producing up to 20 unique bile acid metabolites. The 7α-dehydroxylation of the bile acids is the most physiologically important bile acid biotransformation. All known intestinal bacteria capable of bile acid 7α-dehydroxylation are anaerobic, gram-positive rods of the genera Clostridium and Eubcicterium. Bile acid 7α-dehydroxylating bacteria often contain bile salt hydrolase, which hydrolyzes the peptide bond in taurine-conjugated bile acids to yield a free bile …

Study Of Polyaromatic Hydrocarbons Emitted In The Fly Ash From Coal Combustion In A Fluidized Bed Combuster, Rebecca Heltsley

Masters Theses & Specialist Projects

Exposure to Polyaromatic Hydrocarbons (PAHs) has long been identified as an environmental concern because of their carcinogenic and mutagenic effects. The Environmental Protection Agency (EPA) has developed a list of 16 PAHs that are found on the Priority Pollutant List due to the extensive amount of data suggesting the hazards of these compounds. These toxic compounds are often emitted into the atmosphere by anthropogenic sources, such as combustors. Therefore, analysis of these compounds must be conducted during coal combustion. Two 1000-hour coal combustion burns were performed using the 0.1 MWth bench-scale fluidized bed combustor (FBC), which is found in the …

Reducing Mass Degeneracy In Sar By Ms By Stable Isotopic Labeling, Chris Bailey-Kellogg, John J. Kelley Iii, Cliff Stein, Bruce Randall Donald

Dartmouth Scholarship

Mass spectrometry (MS) promises to be an invaluable tool for functional genomics, by supporting low-cost, high-throughput experiments. However, large-scale MS faces the potential problem of mass degeneracy -- indistinguishable masses for multiple biopolymer fragments (e.g. from a limited proteolytic digest). This paper studies the tasks of planning and interpreting MS experiments that use selective isotopic labeling, thereby substantially reducing potential mass degeneracy. Our algorithms support an experimental-computational protocol called Structure-Activity Relation by Mass Spectrometry (SAR by MS), for elucidating the function of protein-DNA and protein-protein complexes. SAR by MS enzymatically cleaves a crosslinked complex and analyzes the resulting mass spectrum …

Development Of Bismaleimide/Cyanate Ester Based Aerospace Polymers For Possible Use In Nasa's Relaunchable Vehicles Program, Brian Sisk

Masters Theses & Specialist Projects

Since the beginning of the space age, the goal of materials development in the aerospace industry has been to replace metal alloys with much lighter polymer resins, while maintaining the strength over a wide temperature range characteristic of metals. Polymers such as polyimides and epoxies have been used to satisfy many needs, but strength, temperature resistance, and ease of processing are difficult to incorporate into a single polymer. Because of this gap, bismaleimides and cyanate esters, and possibly combinations of the two, are seen as having potential in applications where ease of processing characteristic of epoxies is desired, but for …