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Full-Text Articles in Physical Sciences and Mathematics

Investigation Of The Charge Transfer Properties Of Electrodes Modified By The Spontaneous Adsorption Of Unsymmetrical Dialkyl Sulfides, Minhui Zhang, Mark Anderson Jul 1994

Investigation Of The Charge Transfer Properties Of Electrodes Modified By The Spontaneous Adsorption Of Unsymmetrical Dialkyl Sulfides, Minhui Zhang, Mark Anderson

Mark R. Anderson

Electrodes modified by the spontaneous adsorption of unsymmetrical dialkyl sulfides are used to investigate two monolayer properties, structural disorder and solvent compatibility, that may be of importance in determining the ability for faradaic charge transport to occur in the presence of the monolayer. Two groups of dialkyl sulfides are prepared and studied: a purely hydrocarbon dialkyl sulfide with the structure CH3(CH2)17S(CH2)nCH3, where n, = 7,9, and 17, and an acid containing dialkyl sulfide with the structure CH3(CH2)17S(CH2)mCOOH, where m = 7, 10, and 15. Reflection infrared spectroscopy of the hydrocarbon dialkyl sulfide reveals that the monolayer structure is disordered, when …


Effect Of Applied Potential Upon The In Situ Structure Of Self-Assembled Monolayers On Gold Electrodes, Mark Anderson, Marilyn Gatin May 1994

Effect Of Applied Potential Upon The In Situ Structure Of Self-Assembled Monolayers On Gold Electrodes, Mark Anderson, Marilyn Gatin

Mark R. Anderson

Polarization modulation Fourier transform infrared reflection absorption spectroscopy (PM-FTIRRAS) has been utilized to study the in situ structure of octadecanethiol when adsorbed to gold electrode surfaces and with the application of potential to the substrate. It is found that applied potential has little effect upon the spectrum of the monolayer in the presence of D2O solutions containing 0.10 M NaClO4. The presence of an acetonitrile solution contacting the monolayer leads to small changes in the infrared spectrum relative to that seen in D2O solutions, suggestive of some small disordering of the monolayer caused by the presence of the acetonitrile. With …


Application Of The Quartz Crystal Microbalance To Characterize The Interaction Of Solutes With Modified Interfaces, John Roush, David Thacker, Mark Anderson May 1994

Application Of The Quartz Crystal Microbalance To Characterize The Interaction Of Solutes With Modified Interfaces, John Roush, David Thacker, Mark Anderson

Mark R. Anderson

Piezoelectric quartz crystals, modified by the spontaneous adsorption of either 4-aminothiophenol or octadecanethiol, were utilized to investigate the selective interactions that exist between solutes and the surface modification layer. It is found that the exposed amine functionality of the 4-aminothiophenol monolayer increases the sensitivity of the quartz crystal microbalance to phenols relative to the response found at either a crystal modified with an octadecanethiol monolayer or an unmodified quartz crystal. Protonation of the amino group decreases the sensitivity of the 4-aminothiophenol modified crystal toward the phenol solutes, to a level approximately the same as seen for the octadecanethiol monolayer and …


6li And 15n Nuclear Magnetic Resonance Studies Of Mixed Alkali Metal Cation Hexamethyldisilazide Bases, Michael Nichols, Delia Waldmüller, Paul Williard Jan 1994

6li And 15n Nuclear Magnetic Resonance Studies Of Mixed Alkali Metal Cation Hexamethyldisilazide Bases, Michael Nichols, Delia Waldmüller, Paul Williard

Michael A Nichols

No abstract provided.


The Power Of Visualization: Notes From A Mathematica Course, Stan Wagon Dec 1993

The Power Of Visualization: Notes From A Mathematica Course, Stan Wagon

Stan Wagon, Retired

No abstract provided.


Protein S-Thiolation And Dethiolation, James Thomas, Yuh-Cherng Chai, Che-Hun Jung Dec 1993

Protein S-Thiolation And Dethiolation, James Thomas, Yuh-Cherng Chai, Che-Hun Jung

Yuh-Cherng Chai

No abstract provided.


Hexagons And Squares In A Passive Nonlinear Optical System, John Geddes, R.A. Indik, J.V. Moloney, Willie Firth Dec 1993

Hexagons And Squares In A Passive Nonlinear Optical System, John Geddes, R.A. Indik, J.V. Moloney, Willie Firth

John B. Geddes

Pattern formation is analyzed and simulated in a nonlinear optical system involving all three space dimensions as well as time in an essential way. This system, counterpropagation in a Kerr medium, is shown to lose stability, for sufficient pump intensity, to a nonuniform spatial pattern. We observe hexagonal patterns in a self-focusing medium, and squares in a self-defocusing one, in good agreement with analysis based on symmetry and asymptotic expansions.