Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Chemistry

1990

Institution
Keyword
Publication
Publication Type
File Type

Articles 1 - 30 of 154

Full-Text Articles in Physical Sciences and Mathematics

In Situ Infrared Evidence For The Electrochemical Incorporation Of Hydrogen Into Si And Ge, K. C. Mandal, F. Ozanam, J.-N. Chazalviel Dec 1990

In Situ Infrared Evidence For The Electrochemical Incorporation Of Hydrogen Into Si And Ge, K. C. Mandal, F. Ozanam, J.-N. Chazalviel

Faculty Publications

No abstract provided.


Matrix-Infrared Spectra Of Structural Isomers Of The Phosphorus Oxysulfide P4s3o, Zofia Mielke, Lester Andrews, Kiet A. Nguyen, Mark S. Gordon Dec 1990

Matrix-Infrared Spectra Of Structural Isomers Of The Phosphorus Oxysulfide P4s3o, Zofia Mielke, Lester Andrews, Kiet A. Nguyen, Mark S. Gordon

Mark S. Gordon

Photolysis of the P 4S3--03 molecular complex in solid argon with red light produced two sets of new infrared absorptions including terminal PO and symmetric P-S-P stretching modes, which are assigned to structural isomers of P4S30 with terminal oxygen at the apex and base phosphorus positions of P4S3. Further ultraviolet photolysis produced evidence for oxo-bridged P4S30 and a secondary product, P4S30 2.


73. Professor Cristofor I. Simionescu On His 70th Birthday, Otto Vogl, Ioan I. Negulescu Dec 1990

73. Professor Cristofor I. Simionescu On His 70th Birthday, Otto Vogl, Ioan I. Negulescu

Otto Vogl

No abstract provided.


Organic And Polymeric Nonlinear Optical Materials, Otto Vogl, Donald R. Ulrich Dec 1990

Organic And Polymeric Nonlinear Optical Materials, Otto Vogl, Donald R. Ulrich

Otto Vogl

No abstract provided.


Polymer Science In Hungary, Part Iii. The Industrial Research Institutes And Their Factories, Otto Vogl, Gyula Hardy, Sandor Doubravsky, Margit Iring, Ferenc Tudos Dec 1990

Polymer Science In Hungary, Part Iii. The Industrial Research Institutes And Their Factories, Otto Vogl, Gyula Hardy, Sandor Doubravsky, Margit Iring, Ferenc Tudos

Otto Vogl

No abstract provided.


Intracellular Degradation Of Ribosomes In A Mesophilic And A Thermophilic Species Of Bacillus, Joe William Davis Dec 1990

Intracellular Degradation Of Ribosomes In A Mesophilic And A Thermophilic Species Of Bacillus, Joe William Davis

Dissertations

The rates of intracellular degradation of ribosomal proteins were compared in a mesophilic and a thermophilic species of Bacillus. Cells were grown under various incubation conditions in the presence of a 14^C-protein hydrolysate m order to label the ribosomes. Rates of ribosome degradation were evaluated in terms of changes in the specific activity of in vivo ribosomes as a function of incubation time. The results indicated that, under most conditions, ribosomes were degraded (in vivo) at similar rates in both the mesophile and the thermophile. In some studies, ribosome degradation rates were slightly faster for the thermophile than for the …


Purification And Characterization Of A Dna Polymerase From The Cyanobacterium Anacystis Nidulans R2, Hsiu-Jin Lin, Gordon C. Cannon, Sabine Heinhorst Nov 1990

Purification And Characterization Of A Dna Polymerase From The Cyanobacterium Anacystis Nidulans R2, Hsiu-Jin Lin, Gordon C. Cannon, Sabine Heinhorst

Faculty Publications

A DNA polymerase has been highly purified from Anacystis nidulans R2. Electrophoretic analysis in sodium dodecyl sulfate-polyacrylamide gels revealed that the final fraction contains three bands of Mr 107,000, 93,000, and 51,000, respectively. Analysis of purified DNA polymerase activity in situ indicates that of the three polypeptides the Mr 107,000 species has the catalytic activities. The native molecular weight of the enzyme was estimated by glycerol gradient sedimentation to be 100,000. The enzyme has an absolute requirement for a divalent cation. Mg2+ can be replaced with Mn2+, but the DNA polymerase is less active. Potassium …


Kinetic-Energy Density Functional For A Special Shape-Invariant Potential Of A One-Dimensional Two-Level System , Jiushu Shao, John J. Stezowski Nov 1990

Kinetic-Energy Density Functional For A Special Shape-Invariant Potential Of A One-Dimensional Two-Level System , Jiushu Shao, John J. Stezowski

John J. Stezowski Publications

By introducing the concept of supersymmetry to quantum mechanics, several authors have shown that exactly soluble potentials, including all those well known, are easily constructed. Is the kinetic-energy density functional corresponding to these potentials a simple form? We show that the answer is no, even to the simplest one, the harmonic potential, if one builds the kinetic-energy density functional from the reduced density matrix.


Coupled Kinetic Analysis Of Cleavage Of Dna By Esperamicin And Calicheamicin, Hiroko Kishlkawa, Ying-Ping Jiang, Jerry Goodisman Nov 1990

Coupled Kinetic Analysis Of Cleavage Of Dna By Esperamicin And Calicheamicin, Hiroko Kishlkawa, Ying-Ping Jiang, Jerry Goodisman

Chemistry - All Scholarship

A coupled kinetic analysis of esperamicin, calicheamicin, and DNase I cleavage of covalently closed circular PM2 DNA has been carried out. Analysis of the optical density data derived from agarose gel electrophoresis experiments shows that esperamicin A,, like the hydrolytic enzyme DNase I, produces mainly single-strand breaks in DNA. These agents cause covalently closed circular form I DNA to be initially converted to nicked circular form I1 DNA. However, the ratio of the rate constant for this process (k,') to that associated with conversion of form I1 to linear form I11 DNA ( k i ) is not consistent with …


Hplc Analysis Of Amino Acid-Derived Chloramines, Thomas Goyne, Tracy Inskeep, Heather Greenleaf Nov 1990

Hplc Analysis Of Amino Acid-Derived Chloramines, Thomas Goyne, Tracy Inskeep, Heather Greenleaf

Thomas Goyne

No abstract provided.


9th International Symposium On Cationic Polymerization And Related Ionic Processes, Otto Vogl Nov 1990

9th International Symposium On Cationic Polymerization And Related Ionic Processes, Otto Vogl

Otto Vogl

No abstract provided.


Polymer Science In Hungary, Part Ii. The Universities In Hungary, Otto Vogl, Jozef Varga, Margit Iring, Ferenc Tudos Nov 1990

Polymer Science In Hungary, Part Ii. The Universities In Hungary, Otto Vogl, Jozef Varga, Margit Iring, Ferenc Tudos

Otto Vogl

No abstract provided.


74. Professor Cristofor I. Simionescu On His 70th Birthday, Otto Vogl, Ioan I. Negulescu Nov 1990

74. Professor Cristofor I. Simionescu On His 70th Birthday, Otto Vogl, Ioan I. Negulescu

Otto Vogl

No abstract provided.


Part I: Oxidation Of Heavy Metal Sulfides In Relation To The Environment; Part Ii: Fundamental Theory & Experiments Concerning Gas Chromatography & Mass Spectrometry, Judith Morgan Nov 1990

Part I: Oxidation Of Heavy Metal Sulfides In Relation To The Environment; Part Ii: Fundamental Theory & Experiments Concerning Gas Chromatography & Mass Spectrometry, Judith Morgan

Masters Theses & Specialist Projects

Oxidation of heavy metal sulfides is a thermodynamically spontaneous process. Because of this, metal sulfides in the presence of oxygen are not stable. Currently there are over 100 streams and rivers, within the U.S., contaminated with heavy metal mine drainage; therefore an approved method of restoration is necessary. Precipitation of heavy metals as sulfides using H2S as a reductant has been favorably reviewed as a restorative technique to clean up mining areas. However, using this technique on the laboratory scale does not prove to be a viable answer and shows strong pH dependence.

In the past three years …


Nitrogenase Substrates As Intercluster Bridging Units Between The Molybdenum Atoms In Doubly Bridged, Double Cubanes. The Synthesis And Characterization Of The [Mofe3s4cl2(Cl4cat)]2(.Mu.2-S)(.Mu.2-L)]N- Anions (L = N2h4, N = 4; L = Cn-, N = 5), Paul Challen, Sang Koo, C. Kim, W. Dunham, D. Coucouvanis Oct 1990

Nitrogenase Substrates As Intercluster Bridging Units Between The Molybdenum Atoms In Doubly Bridged, Double Cubanes. The Synthesis And Characterization Of The [Mofe3s4cl2(Cl4cat)]2(.Mu.2-S)(.Mu.2-L)]N- Anions (L = N2h4, N = 4; L = Cn-, N = 5), Paul Challen, Sang Koo, C. Kim, W. Dunham, D. Coucouvanis

Paul R. Challen

No abstract provided.


Spreadsheets And Their Relation To Reality (Presentation), Donald H. Stedman, Gary A. Bishop, James E. Peterson, Paul L. Guenther Oct 1990

Spreadsheets And Their Relation To Reality (Presentation), Donald H. Stedman, Gary A. Bishop, James E. Peterson, Paul L. Guenther

Fuel Efficiency Automobile Test Publications

No abstract provided.


Structure And Stability Of Hexacoordinated Sila Dianions, Mark S. Gordon, Marshall T. Carroll, Larry P. Davis, Larry W. Burggraf Oct 1990

Structure And Stability Of Hexacoordinated Sila Dianions, Mark S. Gordon, Marshall T. Carroll, Larry P. Davis, Larry W. Burggraf

Mark S. Gordon

The structures and stabilities of hexacoordinated silicon-containing dianions SiX6 2- have been investigated by using both ab initio (X= H, F) and semiempirical AMI (X= H, F, OH, Me, Cl) calculations. Both methods predict the hexacoordinated structures to be minima on the potential energy surfaces, although the semiempirical barriers for the reactions SiX6 2- -+ Six5- + x- appear to be rather overestimated based on the ab initio results for X = H, F. The positive charge on the central silicon atom actually increases as the number of ligands increases, and the role of d orbitals on that atom appears …


Polymer Science In Hungary. Part I. The Institutes Of The Hungarian Academy Of Sciences, Otto Vogl, Ferenc Tudos, Margit Iring Oct 1990

Polymer Science In Hungary. Part I. The Institutes Of The Hungarian Academy Of Sciences, Otto Vogl, Ferenc Tudos, Margit Iring

Otto Vogl

No abstract provided.


First Pacific Polymer Conference, Jane C. Vogl, Gerald Kirshenbaum Oct 1990

First Pacific Polymer Conference, Jane C. Vogl, Gerald Kirshenbaum

Otto Vogl

No abstract provided.


Self-Calibrating Position-Sensitive Silicon Detectors, J. T. Walton, H. A. Sommer, Gordon J. Wozniak, Graham F. Peaslee, D. R. Bowman, W. L. Kehoe, A. Moroni Oct 1990

Self-Calibrating Position-Sensitive Silicon Detectors, J. T. Walton, H. A. Sommer, Gordon J. Wozniak, Graham F. Peaslee, D. R. Bowman, W. L. Kehoe, A. Moroni

Faculty Publications

Position-sensitive silicon detectors with discrete position output signal levels, which have been developed for heavy ion reaction studies at the Lawrence Berkeley Laboratory are discussed. The detectors, both 300- and 5000-μm thick, for use in ΔE-E telescopes, use a series of high and low conductivity strips on the detector p+ contact to produce a position signal with 15 discrete levels. Since the position of the signals from the strips is known, the detectors are self-calibrating against position nonlinearities. Some aspects of the fabrication of both the 300- and 5000-μm detectors are discussed, along with their operating characteristics. Illustrative experimental results …


Ua66/7/2 Hilltopper News, Wku Chemistry Oct 1990

Ua66/7/2 Hilltopper News, Wku Chemistry

WKU Archives Records

Newsletter created by and about the WKU Chemistry department.


Structural And Energetic Evidence For Oxygen-Lithium-Nitrogen Chelation In A Model For Asymmetric Induction., Edward Arnett, Michael Nichols, Andrew Mcphail Sep 1990

Structural And Energetic Evidence For Oxygen-Lithium-Nitrogen Chelation In A Model For Asymmetric Induction., Edward Arnett, Michael Nichols, Andrew Mcphail

Michael A Nichols

No abstract provided.


Theoretical Study Of Pseudorotation Of Pentacoordinated Silicon Anions: The Prototypical Sih5-, Mark S. Gordon, Theresa L. Windus, Larry W. Burggraf, Larry P. Davis Sep 1990

Theoretical Study Of Pseudorotation Of Pentacoordinated Silicon Anions: The Prototypical Sih5-, Mark S. Gordon, Theresa L. Windus, Larry W. Burggraf, Larry P. Davis

Mark S. Gordon

Ab initio and semiempirical calculations are used to analyze the minimum energy path for the pseudorotation of SiH5-. Both AMI and MP2/6-31++G(d,p) predict pseudorotation barriers of 2.4 kcal/mol. A decomposition of the projected vibrational frequencies along the path is used to assist in the interpretation of the process.


Predicted Enthalpies Of Formation For Silaethylene, Disilene, And Their Silylene Isomers, Jerry A. Boatz, Mark S. Gordon Sep 1990

Predicted Enthalpies Of Formation For Silaethylene, Disilene, And Their Silylene Isomers, Jerry A. Boatz, Mark S. Gordon

Mark S. Gordon

Enthalpies of formation of silaethylene (SiH2=CH2), methylsilylene (HSiCH3), disilene (SiH2=SiH2), and silylsilylene (HSiSiH3) are predicted by using the recently developed GAUSSIAN-! method for computing accurate molecular energies. The predicted enthalpies of formation of the silylenes are compared with enthalpies of formation determined from isodesmic reactions. Very good agreement is found between these two methods and improved values for the enthalpies of formation of silaethylene and disilene are suggested.


Second Euro-American Conference In Oxford On “Functional Polymers And Biopolymers”, Otto Vogl, Jane C. Vogl Sep 1990

Second Euro-American Conference In Oxford On “Functional Polymers And Biopolymers”, Otto Vogl, Jane C. Vogl

Otto Vogl

No abstract provided.


Bis(1h+-Pyrazinium N4-Oxide) Dichromate, Gary L. Gard, Roger D. Willett, W. W. Paudler, R. M. Sheets, Mark R. Pressprich Sep 1990

Bis(1h+-Pyrazinium N4-Oxide) Dichromate, Gary L. Gard, Roger D. Willett, W. W. Paudler, R. M. Sheets, Mark R. Pressprich

Chemistry Faculty Publications and Presentations

2C₄H₅N₂O⁺.Cr₂O²₇⁻, Mᵣ=410∙2, monoclinic, P2₁, a=8∙(2), b=6∙132 (2), c=14∙493 (4) Å, β=94∙50 (2)°, V=708∙8 (3) ų, Z=2, Dₓ=1∙92 g cm⁻³, Mο Κα, λ=0∙71069 Å, μ=15∙5 cm⁻¹, F(000)=412, T=293 K, R=0∙0602 for 1980 unique observed reflections with F≥3σ(F). The structure consists of discrete dinegative dichromate anions hydrogen bonded to monopositive pyrazinium N-oxide cations (N―H∙∙∙O=2∙724, 2∙644 Å). A strong hydrogen bond to the bridging O atom in the Cr₂O²₇⁻ anion leads to significant lengthening of the bridging Cr―O bonds. A short C―H∙∙∙O interaction (3∙180 Å) is also observed.


Statics And Dynamics Of Organic Charge-Transfer Crystals: The Orientational Phase Transition In A-Tcnb, Karl-Heinz Brose, Tadeusz Luty, Craig J. Eckhardt Aug 1990

Statics And Dynamics Of Organic Charge-Transfer Crystals: The Orientational Phase Transition In A-Tcnb, Karl-Heinz Brose, Tadeusz Luty, Craig J. Eckhardt

Craig J. Eckhardt Publications

Crystal potential energy calculations and lattice dynamical calculations are presented for the high-temperature and low-temperature phases of the charge-transfer complex crystal of anthracene with 1,2,4,5-tetracyanobenzene using the method of atom–atom potentials. For several different sets of the “exp-6'' potential parameters the crystal energy was minimized with respect to the lattice constants and orientations and positions of the molecules in the unit cell. These calculations show good agreement with the experimental values. The equilibrium crystal structures were used to calculate the lattice dynamics in the harmonic approximation for both crystal modifications. In the phonon dispersion curves lattice modes were discovered that …


Reductive Chemistry Of Dicyanoalkane Reactive Intermediates, Beshakeh Fonkeng Aug 1990

Reductive Chemistry Of Dicyanoalkane Reactive Intermediates, Beshakeh Fonkeng

Masters Theses & Specialist Projects

Radical ions are reactive intermediates that are both radicals and ions (either a radical cation or a radical anion). The intrinsic properties of radical ions are not yet well -characterized. Such knowledge is mechanistically important to the organic chemist.

The specific question that motivates this research is as follows: is it possible to controllably express free radical processes in a radical ion independent of ionic chemistry (and vice versa) and, if so, what factors dictate which type of chemistry is expressed?

Our investigation focused on the chemistry of radical anions of dicyanoalkanes that are formed upon metal reduction. Factors influencing …


Argon-Photoion–Auger-Electron Coincidence Measurements Following K-Shell Excitation By Synchrotron Radiation, Jon C. Levin, C. Biedermann, N. Keller, L. Liljeby, C.-S. O, R. T. Short, Ivan A. Sellin, Dennis W. Lindle Aug 1990

Argon-Photoion–Auger-Electron Coincidence Measurements Following K-Shell Excitation By Synchrotron Radiation, Jon C. Levin, C. Biedermann, N. Keller, L. Liljeby, C.-S. O, R. T. Short, Ivan A. Sellin, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

Argon photoion spectra have been obtained for the first time in coincidence with K-LL and K-LM Auger electrons, as a function of photon energy. The simplified charge distributions which result exhibit a much more pronounced photon-energy dependence than do the more complicated noncoincident spectra. In the near-K-threshold region, Rydberg shakeoff of np levels, populated by resonant excitation of K electrons, occurs with significant probability, as do double-Auger processes and recapture of the K photoelectron through postcollision interaction.


Spectroelectrochemical Investigation Of The Double Layer Structure And Properties, Mark Anderson Jul 1990

Spectroelectrochemical Investigation Of The Double Layer Structure And Properties, Mark Anderson

Mark R. Anderson

No abtract is currently available.