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Articles 30241 - 30270 of 34560

Full-Text Articles in Physical Sciences and Mathematics

The Influence Of Cathode Ingredients In Zinc Chloride Type Battery On The Discharge Ability, Shen Qi, Zhuang Biao Feb 1996

The Influence Of Cathode Ingredients In Zinc Chloride Type Battery On The Discharge Ability, Shen Qi, Zhuang Biao

Journal of Electrochemistry

The influence of cathodic powder ingredients in ZnCl_2 type heavy duty battery on the discharge ability has been studied, a suitable battery ingredients is founds.


Study Of Electrochemical Behaviour Of Myoglobin Using Cyclic Voltammetry And Synchronous Fluorescence Spectroscopy, Ju Chou, Haihong Zhou, Tianhong Lu, Yue Wu Feb 1996

Study Of Electrochemical Behaviour Of Myoglobin Using Cyclic Voltammetry And Synchronous Fluorescence Spectroscopy, Ju Chou, Haihong Zhou, Tianhong Lu, Yue Wu

Journal of Electrochemistry

Myoglobin undergoes irreversible heterogeneous electron transfer reactions at bare metal electroeds. Thus, much effort has been devoted to obtain quasi-reversible electrochemical reactions of myoglobin at metal electrodes modified with mediators ̄(1~3). However, the electron transfer rates at the above modified electrodes is very small so that the spectroelectrochemical techniques should be used in the most of studies. Recently, Taniguchi et al ̄[4]. reported that a quasi-reversible electrochemical reaction of the purified horse heart myoglobin was observed at an indium oxide electrode with cyclic voltammetry technique. It was suggested that high purification of myoglobin may be the main reason for obtaining a quasi-reversible …


Ftis Observation Of Twin Adsorbates Of Co On Rh Electrode In Acid Solution, Wenfeng Lin, Shigang Sun Feb 1996

Ftis Observation Of Twin Adsorbates Of Co On Rh Electrode In Acid Solution, Wenfeng Lin, Shigang Sun

Journal of Electrochemistry

Because of its great importance both in electrocatalysis and C1 chemistry applications, the adsorption of CO on metallic electrodes such as Pt, Pd, Au, Ag, RhF ̄[1~2], etc. has been extensively studied by in situ infrared spectroscopy Since 1981. In all these studies only three types of CO adsorbates, i. e. , linear (2 090~2 000 cm ̄(-1)), bridgrd (2 000~1 900 cm ̄(-1)) or multi-bonded (1900~1 800 cm ̄(-1)) species, were identified. A different absorbate, twin CO on rhodium ((Rh (CO)2) , does exist on the solid/gas interface of highly dispersed Rh or Rhn clusters[3~4] on supports,this species originating a doublet at 2100 …


Studies Of The Importance Of Molecular Structure And Orientation To Adhesive Interactions At Interfaces, Cynthia Kraft, Mark Anderson Feb 1996

Studies Of The Importance Of Molecular Structure And Orientation To Adhesive Interactions At Interfaces, Cynthia Kraft, Mark Anderson

Mark R. Anderson

No abstract is currently available.


Gas–Liquid Nucleation In Two-Dimensional Fluids, Xiao Cheng Zeng Feb 1996

Gas–Liquid Nucleation In Two-Dimensional Fluids, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

A nonclassical theory of nucleation, based on the density-functional (DF) approach, is developed for the gas–liquid transitions of two-dimensional (2D) Lennard-Jones (LJ) fluids. The methods of Weeks–Chandler–Andersen perturbation theory are used to approximate the LJ potential with a temperature-dependent hard-disk diameter plus an attractive tail. The resulting free energy functional is then used to calculate the free energy barrier to nucleation. We find that the curvature of the 2D nucleus is not important to the rate of nucleation (in contrast to the 3D counterpart). The effect of curvature is readily inferred from the ratio of nucleation rate from classical Becker–Dö̈ring …


Heme Proton Resonance Assignments And Kinetics Study In High-Spin And Mixed-Spin Metmyoglobin Complexes By Chemical Exchange Nmr Spectroscopy, Ying Luo Feb 1996

Heme Proton Resonance Assignments And Kinetics Study In High-Spin And Mixed-Spin Metmyoglobin Complexes By Chemical Exchange Nmr Spectroscopy, Ying Luo

Dissertations and Theses

NMR studies of paramagnetic hemoproteins have improved significantly our understanding of the structure-function relationship of hemoproteins in general. Up to date most of the studies focus on low-spin ferric systems which are characterized by relatively narrow resonance peaks and concomitant better resolution.

However, characterizing in detail the NMR spectra of high-spin ferric hemoproteins is important since there are several hemoproteins, such as peroxidases, catalases, oxygenases, and some ferricytochromes that contain high-spin iron (III) in their biologically active forms. Yet assigning resonances from heme peripheral protons and/or heme pocket residues in high-spin myoglobins is a daunting undertaking. Only a sparse number …


Multifragment Production In Au+Au At 35 Mev/U, M. D'Agostino, P. F. Mastinu, P. M. Milazzo, M. Bruno, D. R. Bowman, P. Buttazzo, L. Celano, N. Colonna, J. D. Dinius, A. Ferrero, M. L. Fiandri, C. K. Gelbke, T. Glasmacher, F. Gramegna, D. O. Handzy, D. Horn, W. C. Hsi, M. Huang, I. Iori, G. J. Kunde, M. A. Lisa, W. G. Lynch, L. Manduci, G. V. Margagliotti, C. P. Montoya, A. Moroni, Graham F. Peaslee, F. Petruzzelli, L. Phair, R. Rui, C. Schwarz, M. B. Tsang, G. Vannini, C. Williams Feb 1996

Multifragment Production In Au+Au At 35 Mev/U, M. D'Agostino, P. F. Mastinu, P. M. Milazzo, M. Bruno, D. R. Bowman, P. Buttazzo, L. Celano, N. Colonna, J. D. Dinius, A. Ferrero, M. L. Fiandri, C. K. Gelbke, T. Glasmacher, F. Gramegna, D. O. Handzy, D. Horn, W. C. Hsi, M. Huang, I. Iori, G. J. Kunde, M. A. Lisa, W. G. Lynch, L. Manduci, G. V. Margagliotti, C. P. Montoya, A. Moroni, Graham F. Peaslee, F. Petruzzelli, L. Phair, R. Rui, C. Schwarz, M. B. Tsang, G. Vannini, C. Williams

Faculty Publications

Multifragment disintegration has been measured with a high efficiency detection system for the reaction Au + Au at E/A = 35 MeV. From the event shape analysis and the comparison with the predictions of a many-body trajectories calculation the data, for central collisions, are compatible with a fast emission from a unique fragment source.


Photoinduced Electron Transfer Along A Beta-Sheet Mimic, Alexei B. Gretchikhine, Michael Y. Ogawa Feb 1996

Photoinduced Electron Transfer Along A Beta-Sheet Mimic, Alexei B. Gretchikhine, Michael Y. Ogawa

Chemistry Faculty Publications

Electron energy-loss spectroscopy (EELS) is used to determine the energies of low-lying singlet and triplet states of the title compound. The EELS measurements give a splitting of 0.45 eV between the two lowest π f π* singlet states, as confirmed by optical absorption measurements, but do not give a discernable splitting between the corresponding triplet states. The experimental results are interpreted with the aid of ab initio electronic structure calculations using the CIS and CASPT2 methods. The calculations are consistent with the experiments, giving a much larger splitting between the π f π* singlet as compared to the π f …


Continuous Monitoring Of Volatile Organic Compound Emissions Using Microtrap Based Injection Technique And Gas Chromatography, Wenjun Chen Jan 1996

Continuous Monitoring Of Volatile Organic Compound Emissions Using Microtrap Based Injection Technique And Gas Chromatography, Wenjun Chen

Theses

A microtrap is made by packing a small diameter tubing with an adsorbent. The microtrap can be rapidly heated with a pulse of electrical current resulting in a sharp desorption that can act as an injection for GC separation. The microtrap can be used in several configurations to concentrate and inject sample in continuous, on-line monitoring system.

In this research a laboratory scale catalytic incinerator was set up and volatile organic compounds in the incinerator effluents were monitored using the microtrap based injection systems. The detection systems used were gas chromatography and nonmethane organic carbon (NMOC) analyzer. Conventional sample valve, …


Construction Of Accurate Molecular Models Using Laser Stereolithography And Determination Of Nmr Spectra For Amiloride Hydrochloride And Its Free Base, Ana Deborah Ofsievich Jan 1996

Construction Of Accurate Molecular Models Using Laser Stereolithography And Determination Of Nmr Spectra For Amiloride Hydrochloride And Its Free Base, Ana Deborah Ofsievich

Theses

Accurate molecular models were constructed by a rapid prototyping process, called stereolithography. This process uses a computer-controlled laser to cure and solidify a photosensitive liquid polymer. Using a computer-aided design (CAD) program, spheres of appropriate van der Waals or CPK radii were drawn and placed in the three dimensional CAD space, in accordance with the atomic coordinates obtained from quantum mechanical calculations and from neutron diffraction data. These design data were used to drive the stereolithography system where the models were built in the same shape as the CAD image. The models built for the purpose of this work consisted …


Vanadium(Iv) Complexes With Mixed O,S Donor Ligands. Syntheses, Structures, And Properties Of The Anions Tris(2-Mercapto-4-Methylphenolato)Vanadate(Iv) And Bis(2-Mercaptophenolato)Oxovanadate(Iv), Paul Klich, Andrew Daniher, Paul Challen, David Mcconville, Wiley Youngs Jan 1996

Vanadium(Iv) Complexes With Mixed O,S Donor Ligands. Syntheses, Structures, And Properties Of The Anions Tris(2-Mercapto-4-Methylphenolato)Vanadate(Iv) And Bis(2-Mercaptophenolato)Oxovanadate(Iv), Paul Klich, Andrew Daniher, Paul Challen, David Mcconville, Wiley Youngs

Paul R. Challen

Reaction of VO(acac)2 with 2-mercaptophenol (mpH2) in the presence of triethylamine gives the mononuclear tris complex (Et3NH)2[V(mp)3] (1), in which the vanadyl oxygen has been displaced. An analogous reaction using 2-mercapto-4-methylphenol (mmpH2) afforded (Et3NH)(PNP)[V(mmp)3] (2), which was structurally characterized. 2 crystallizes in the orthorhombic space group Pna21 with unit cell parameters (at −163 °C) a = 23.974(7) Å, b = 9.569(4) Å, c = 25.101(6) Å, and Z = 4. The coordination geometry around the vanadium is between octahedral and trigonal prismatic. Reaction of VO(acac)2 with the sodium salt of 2-mercaptophenol produces the vanadyl(IV) complex Na(Ph4P)[VO(mp)2]·Et2O (3), which crystallizes in …


Examination Of The Origin, Variation, And Proper Use Of Expressions For The Estimation Of Association Constants By Capillary Electrophoresis, Kimber L. Rundlett, Daniel W. Armstrong Jan 1996

Examination Of The Origin, Variation, And Proper Use Of Expressions For The Estimation Of Association Constants By Capillary Electrophoresis, Kimber L. Rundlett, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

Over the last several decades a variety of techniques have been developed to determine apparent equilibrium constants for molecular association in solution (e.g., to micelles, proteins, cyclodextrins, antibiotics, etc.). The relationships describing binding isotherms appear in several forms and have been given several different names. It is well known that most of these expressions are closely related and that some may be more advantageous than others for experimental or statistical reasons. In the case of electrophoresis, association constants are calculated from the relationship between ligand concentration and the measured electrophoretic mobility of the solute. This relationship has appeared in many …


The Development, Molecular Characterization And Application Of A Model Stratum Corneum Lipid System, Rita M. Hatfield Jan 1996

The Development, Molecular Characterization And Application Of A Model Stratum Corneum Lipid System, Rita M. Hatfield

Dissertations

No abstract provided.


Photophysics And Photochemistry Of Carbocations, Maria R. Valentino Jan 1996

Photophysics And Photochemistry Of Carbocations, Maria R. Valentino

Dissertations

No abstract provided.


Molecular Studies Of Human Erythrocyte Spectrin: Head To-Head Interactions, Nasser Qtaishat Jan 1996

Molecular Studies Of Human Erythrocyte Spectrin: Head To-Head Interactions, Nasser Qtaishat

Dissertations

No abstract provided.


The Synthesis Of Azure B Derivatives: Potential Pro-Drugs For Photodynamic Therapy, Carla M. Edwards Jan 1996

The Synthesis Of Azure B Derivatives: Potential Pro-Drugs For Photodynamic Therapy, Carla M. Edwards

Dissertations

No abstract provided.


Development Of A Unique Photothermal Interferometer, Michael Henry Jan 1996

Development Of A Unique Photothermal Interferometer, Michael Henry

Dissertations

No abstract provided.


Na+-H+ Exchange And Na+-Li+ Exchange In Human Erythrocytes: An Nmr Investigation, Yuling Chi Jan 1996

Na+-H+ Exchange And Na+-Li+ Exchange In Human Erythrocytes: An Nmr Investigation, Yuling Chi

Dissertations

No abstract provided.


An Improved Synthesis Of 2-(Hydroxymethyl)Indene, Hasan Palandoken, William T. Mcmillen, Michael H. Nantz Jan 1996

An Improved Synthesis Of 2-(Hydroxymethyl)Indene, Hasan Palandoken, William T. Mcmillen, Michael H. Nantz

Chemistry and Biochemistry

No abstract provided.


Termolecular Proton Transfer Reactions Assisted By Ionic Hydrogen Bond Formation: Reactions Of Aromatic Cations With Polar Molecules, George M. Daly, Michael Mautner, Y. B. Pithawalla, M. Samy El-Shall Jan 1996

Termolecular Proton Transfer Reactions Assisted By Ionic Hydrogen Bond Formation: Reactions Of Aromatic Cations With Polar Molecules, George M. Daly, Michael Mautner, Y. B. Pithawalla, M. Samy El-Shall

Chemistry Publications

We present a new method that applies resonant‐two‐photon ionization to generate reactant ions selectively in the source of a high‐pressure mass spectrometer (R2PI‐HPMS) for kinetic and equilibrium studies. Applications to reactions that would be obscured otherwise in a complex system are illustrated in mixtures of benzene with polar solvent molecules (S). We observe a novel type of proton transferreactions from C6H6 +• to two S molecules where S=CH3CN, CH3OH, C2H5OH and CH3COOC2H5, and from C6H5CH3 +• to two …


Highly Reactive Form Of Copper And Reagents Thereof, Reuben D. Rieke Jan 1996

Highly Reactive Form Of Copper And Reagents Thereof, Reuben D. Rieke

Chemistry Department: Faculty Publications

A novel Zerovalent copper species and an organocopper reagent are disclosed. The Zerovalent copper species is directly produced by reaction of a reducing agent with a combination of copper(I) cyanide or halide and an alkali metal halide salt. The organocopper reagent resulting from the reaction of the zerovalent copper species and an organic compound having one or more stable anionic leaving groups is a stable reagent that will not significantly homocouple and under controlled conditions tolerates the presence of nitrile, epoxide, imine, enone, ketone, ester, allyl and benzyl groups within the organo radical. The reagent can be controlled so that …


Substitution Reactions Of (C5ph5)Cr(Co)3: Structural, Electrochemical, And Spectroscopic Characterization Of (C5ph5)Cr(Co)2l, L = Pme3, Pme2ph, P(Ome)3, D. John Hammack, Mills M. Dillard, Michael Castellani, Arnold L. Rheingold, Anne L. Rieger, Philip H. Rieger Jan 1996

Substitution Reactions Of (C5ph5)Cr(Co)3: Structural, Electrochemical, And Spectroscopic Characterization Of (C5ph5)Cr(Co)2l, L = Pme3, Pme2ph, P(Ome)3, D. John Hammack, Mills M. Dillard, Michael Castellani, Arnold L. Rheingold, Anne L. Rieger, Philip H. Rieger

Chemistry Faculty Research

The radical complex (C5Ph5)Cr(CO)3 reacts with small, neutral, monodentate Lewis bases (PMe3, PMe2Ph, P(OMe)3) in THF at −78 °C (PMe2Ph reacts at ambient temperature) to yield the monomeric substitution products (C5Ph5)Cr(CO)2L·THF as thermally stable solids. Electrochemical and spectroscopic data are provided. An X-ray crystal structure of the hemisolvate (C5Ph5)Cr(CO)2PMe3·0.5THF was obtained. Frozen-solution ESR spectra of (C5Ph5)Cr(CO)2L in toluene are comparable to those of other low-spin d5 …


The Lipooligosaccharides Of Haemophilus Ducreyi Are Highly Sialylated, William Melaugh, A A. Campagnari, B W. Gibson Jan 1996

The Lipooligosaccharides Of Haemophilus Ducreyi Are Highly Sialylated, William Melaugh, A A. Campagnari, B W. Gibson

Chemistry Faculty Publications

The major lipooligosaccharides of the sexually transmitted pathogen Haemophilus ducreyi 35000 have been previously found to terminate in N-acetyllactosamine and sialyl-N-acetyllactosamine, Neu5Ac alpha 2-->3Gal beta 1-->4GlcNAc (W. Melaugh, N. J. Phillips, A. A. Campagnari, M. V. Tullius, and B. W. Gibson, Biochemistry 33: 13070-13078, 1994). In this study, mass spectrometry and composition analyses have shown that the lipooligosaccharides from three other H. ducreyi strains also contain N-acetyllactosamine and are highly sialylated (approximately 30 to 50%), although one African strain was found to contain neither of these structural features.


Effects Of Radial Thermal Gradients In Hplc, Jennifer Splan Jan 1996

Effects Of Radial Thermal Gradients In Hplc, Jennifer Splan

Honors Theses, 1963-2015

Due to the widespread use of chromatography, improving efficiency in chromatography is continually an area of interest. Researchers have suggested that the method of column temperature control influences efficiency. To insure reproducible retention times, HPLC columns are often thermostated with a water jacket. Under such conditions, however, a radial thermal gradient may arise from the heat produced by friction between the stationary and mobile phases. If the core of the column is allowed to warm up while the walls are kept at a constant temperature, the solute in the core of the column will elute faster than will that at …


The Determination Of The Concentration Of Common Inorganic Anions Using Capillary Zone Electrophoresis: An Analytical Chemistry Laboratory Experiment, Michael A. Janusa Jan 1996

The Determination Of The Concentration Of Common Inorganic Anions Using Capillary Zone Electrophoresis: An Analytical Chemistry Laboratory Experiment, Michael A. Janusa

Faculty Presentations

No abstract provided.


Effects Of Analyte Ph On The Accuracy Of Capillary Zone Electrophoresis As A Quantitative Analytical Technique, Michael A. Janusa Jan 1996

Effects Of Analyte Ph On The Accuracy Of Capillary Zone Electrophoresis As A Quantitative Analytical Technique, Michael A. Janusa

Faculty Presentations

No abstract provided.


Designing A Better Matrix For Solidification/Stabilization Of Hazardous Waste With The Aid Of Bagasse (Lignin) As A Polymer Additive To Cement, Michael A. Janusa Jan 1996

Designing A Better Matrix For Solidification/Stabilization Of Hazardous Waste With The Aid Of Bagasse (Lignin) As A Polymer Additive To Cement, Michael A. Janusa

Faculty Presentations

No abstract provided.


Degradation Studies Of The Non-Lethal Bird Repellent, Methyl Anthranilate, Eugeny Aronov, Larry Clark Jan 1996

Degradation Studies Of The Non-Lethal Bird Repellent, Methyl Anthranilate, Eugeny Aronov, Larry Clark

Larry Clark

Methyl anthranilate (MA), a food grade flavor and fragrance additive, has been reported to be an effective non-lethal bird repellent in a variety of situations. Despite the experimental success of MA, field studies have yielded widely differing levels of efficacy. Diminished efficacy in some field trials prob­ ably results from the failure of specific formulations to retain or protect the active ingredient under natural conditions. Therefore, a clearer understanding of the physical and chemical factors affecting the stability of MA is needed. We undertook a series of laboratory studies on hydrolysis, photolysis and microbial degradation of MA, the results of …


Some Syntactic, Semantic And Prosodic Characteristics In British English Conversation, Philadelphia University Jan 1996

Some Syntactic, Semantic And Prosodic Characteristics In British English Conversation, Philadelphia University

Philadelphia University, Jordan

No abstract provided.


Serum Chemistry Of Bowhead Whales (Balaena Mysticetus), Jerry R. Heidel, L. Michael Philo, Thomas F. Albert, Claire B. Andreasen, Bernadette V. Stang Jan 1996

Serum Chemistry Of Bowhead Whales (Balaena Mysticetus), Jerry R. Heidel, L. Michael Philo, Thomas F. Albert, Claire B. Andreasen, Bernadette V. Stang

Claire B. Andreasen

Sera of 19 male and female bowhead whales (Balaena mysticetus) collected near Barrow, Alaska (USA) between 30 August and 13 October 1992 were evaluated for 18 serum chemistry values. Male bowhead whales had significantly greater creatinine and sodium concentrations, and significantly lower glucose concentrations than females. Pregnant females had greater triglyceride levels than non-pregnant females. The mean concentrations of creatinine, blood urea nitrogen, alkaline phosphatase, total bilirubin, total protein, sodium, potassium, chloride, phosphorus, and calcium were similar to those previously reported from bowhead whales. High aspartate aminotransferase and creatine kinase levels were attributed to muscle damage associated with harpooning.