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Materials Chemistry

2000

Articles 61 - 66 of 66

Full-Text Articles in Physical Sciences and Mathematics

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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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( E p) 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 E p. 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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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 and maintain 10 …

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Behavior Of Grain Boundary Resistivity In Metals Predicted By A Two-Dimensional Model, Rand Dannenberg, Alexander H. King Jan 2000

Behavior Of Grain Boundary Resistivity In Metals Predicted By A Two-Dimensional Model, Rand Dannenberg, Alexander H. King

Alexander H. King

The behavior of a model for the specific grain boundary resistivity in metallic bamboo conductor lines is developed and compared to other theoretical treatments, and to experiment. The grain boundary is modeled as an array of scatterers on a plane. The scatterers are called “vacancy-ion” complexes, in which the vacancy represents the boundary free volume, and the ion is an atom adjacent to the vacancy. Three cases are investigated, that of noninterfering scatterers, a continuum of interfering scatterers, and discrete interfering scatterers. The approximations used lead to a specific grain boundary resistivity ∼10−16 Ω m2 for aluminum, in agreement with …

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Structural Change Of The Mn Cluster During The S2→S3 State Transition Of The Oxygen-Evolving Complex Of Photosystem Ii. Does It Reflect The Onset Of Water/Substrate Oxidation? Determination By Mn X-Ray Absorption Spectroscopy, Wenchuan Liang, Theo A. Toelofs, Roehl M. Cinco, Annette Rompel, Matthew J. Latimer, Edward Yu, Kenneth Sauer, Melvin P. Klein, Vittal K. Yachandra Jan 2000

Structural Change Of The Mn Cluster During The S2→S3 State Transition Of The Oxygen-Evolving Complex Of Photosystem Ii. Does It Reflect The Onset Of Water/Substrate Oxidation? Determination By Mn X-Ray Absorption Spectroscopy, Wenchuan Liang, Theo A. Toelofs, Roehl M. Cinco, Annette Rompel, Matthew J. Latimer, Edward Yu, Kenneth Sauer, Melvin P. Klein, Vittal K. Yachandra

Edward Yu

The oxygen-evolving complex of Photosystem II in plants and cyanobacteria catalyzes the oxidation of two water molecules to one molecule of dioxygen. A tetranuclear Mn complex is believed to cycle through five intermediate states (S0−S4) to couple the four-electron oxidation of water with the one-electron photochemistry occurring at the Photosystem II reaction center. We have used X-ray absorption spectroscopy to study the local structure of the Mn complex and have proposed a model for it, based on studies of the Mn K-edges and the extended X-ray absorption fine structure of the S1 and S2 states. The proposed model consists of …

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Structural And Electrical Characterization Of A Novel Mixed Conductor: Ceo2 - Sm2O3 - Zro2 Solid Solution, W. Huang, P. Shuk, M. Greenblatt, M. Croft, Fanglin Chen, M. Liu Jan 2000

Structural And Electrical Characterization Of A Novel Mixed Conductor: Ceo2 - Sm2O3 - Zro2 Solid Solution, W. Huang, P. Shuk, M. Greenblatt, M. Croft, Fanglin Chen, M. Liu

Faculty Publications

solid solutions were synthesized for the first time by the hydrothermal method. The electrical properties of the solid solutions have been studied in air and under reducing conditions. Solid solutions with the fluorite structure were formed in all of the studied range of substitution after calcination at 1500°C. With increasing substitution up to 30 mol %, the electronic conductivity increases under a reducing atmosphere. The solid solution has good mixed electronic and ionic conductivity; the total conductivity is 0.42 S/cm at and 700°C with an estimated ionic conductivity of ca. .

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