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Articles 30181 - 30210 of 34560

Full-Text Articles in Physical Sciences and Mathematics

Surface Raman Spectra Of Pyridine And 2 Mercaptopyrimidine Adsorbed On Rough Nickel Electrode, Qunjian Huang, Jinsong Gao, Xiongwei Cai, Bingwei Mao, Mingseng Zheng, Zhongqun Tian May 1996

Surface Raman Spectra Of Pyridine And 2 Mercaptopyrimidine Adsorbed On Rough Nickel Electrode, Qunjian Huang, Jinsong Gao, Xiongwei Cai, Bingwei Mao, Mingseng Zheng, Zhongqun Tian

Journal of Electrochemistry

The Raman spectra of pyridine and 2 mercaptopyrimidine (2 MP) adsorbed on bare nickel electrodes roughened by a HNO 3 etching procedure have been obtained for the first time by utilizing a highly sensitive confocal Raman microscope.Their adsorption behaviours are discussed briefly.This primary result illustrates a great potential for in situ Raman spectroscopy in the study of chemical and electrochemical processes of transition metal surfaces.

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Electrochemical And Infrared Studies Of Model Membrane Systems, Mark Anderson May 1996

Electrochemical And Infrared Studies Of Model Membrane Systems, Mark Anderson

Mark R. Anderson

No abstract is available at this time.

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Speciation Of Uranium And Organic Compounds On Solid Matrix Studied By Supercritical Fluid Extraction, Li Chen May 1996

Speciation Of Uranium And Organic Compounds On Solid Matrix Studied By Supercritical Fluid Extraction, Li Chen

FIU Electronic Theses and Dissertations

The liquid extraction and spectrophotometric quantitation of uranium from different solid matrices is compared to supercritical fluid extraction (SFE) using various combinations of 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octadione (FOD), tri-n-butylphosphate (TBP), ethanol, and carbon dioxide measuring the UV absorption of the uranium-FOD complex. The matrix is shown to have a tremendous effect on the extractability of uranium from different solid matrices. Compared to liquid extraction, the SFE method yields higher recoveries, is significantly faster, is of equal or greater precision, and greatly reduces the amount of organic solvents used. In the second part of this work, the speciation of hydrophobic organic compounds (HOCs) in …

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Fluorinated Polymer Films: Synthesis And Characterization, Anja Ulrike Schnurer May 1996

Fluorinated Polymer Films: Synthesis And Characterization, Anja Ulrike Schnurer

Dissertations and Theses

Three polyfluoroalkyl epoxides, (I OCH2CHCH2OCF2CF2SO2F, II OCH2CHCH2(CF2)8F and III OCH2CHCH2O(CF2)CF(CF3)SO2F) were photopolymerized with a cycloaliphatic diepoxide (Cyracure UVR-6110) to form highly crosslinked glassy films. Depth-dependent surface analysis with XPS show that these films are highly enriched with sulfonyl fluoride groups in the outer molecular surface. Film compositions of 17 % wt and more of the fluorinated I and III show surface characteristics of a film composed of 100 % wt of the …

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Methods And Methodologies For Organic Synthesis, Frank Favaloro May 1996

Methods And Methodologies For Organic Synthesis, Frank Favaloro

Honors Theses

Methods and methodologies for organic synthesis

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Epitaxial Growth Of Co3O3 On Coo(100), G.A. Carson, M.H. Nassir, Marjorie Langell May 1996

Epitaxial Growth Of Co3O3 On Coo(100), G.A. Carson, M.H. Nassir, Marjorie Langell

Marjorie A. Langell Publications

Under mildly oxidizing ultrahigh vacuum conditions, it is possible to form on top of CoO(100) single crystal substrates, thin films that have higher oxygen content but that preserve the overall symmetry of the CoO(100) low-energy electron diffraction pattern. X-ray photoelectron spectroscopy (XPS) and high-resolution electron-energy-loss spectroscopy (HREELS) data indicate that the epitaxial film grown on CoO(100) at 625 K and 531027 Torr is Co3O3-like in both oxygen content and XP/HREEL spectroscopic characteristics. Both materials are closest packed in lattice oxygen, with the mismatch of bulk O2-–O2- distances of approximately 5%. However, the Co …

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High Resolution Electron Energy Loss Spectroscopy Of Mno(100) And Oxidized Mno(100), Marjorie Langell, C.W. Hutchings, G.A. Carson , M.H. Nassir May 1996

High Resolution Electron Energy Loss Spectroscopy Of Mno(100) And Oxidized Mno(100), Marjorie Langell, C.W. Hutchings, G.A. Carson , M.H. Nassir

Marjorie A. Langell Publications

Single crystal MnO(100) substrates can be selectively oxidized to produce Mn2O3- and Mn3O4-like surfaces under mild oxidation/reduction conditions readily accessed under ultrahigh vacuum (UHV). MnO(100) yields a characteristic Mn 2p x-ray photoelectron spectroscopy (XPS) satellite structure and appropriate O/Mn concentrations from O 1s/Mn 2p XPS intensity ratios. Its high resolution electron energy loss (HREEL) spectrum shows a series of Fuchs–Kliewer multiple phonon excitations with a single loss energy of 70.9 meV, characteristic of the cubic manganese monoxide structure. However, the HREEL spectral (HREELS) background is high and the …

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Reconnecting The Sciences, John Eggebrecht, Raymond Dagenais, Don Dosch, Norman J. Merczak, Margaret N. Park, Susan C. Styer, David Workman May 1996

Reconnecting The Sciences, John Eggebrecht, Raymond Dagenais, Don Dosch, Norman J. Merczak, Margaret N. Park, Susan C. Styer, David Workman

Faculty Publications & Research

During the last three years at the Illinois Mathematics and Science Academy, we have been working on a partial reconstruction of Whitehead's "one subject matter," a course reconnecting biology, chemistry, earth and space sciences, and physics into an Integrated Science program.

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Optimization Of Porous-Membranes Utilized In Chlor-Alkali Technology Via The Use Of Porosity And Electrochemical Impedance Spectroscopy, Jo Ann Jackson May 1996

Optimization Of Porous-Membranes Utilized In Chlor-Alkali Technology Via The Use Of Porosity And Electrochemical Impedance Spectroscopy, Jo Ann Jackson

Electronic Dissertations and Theses

A fundamental understanding of porous diaphragm membrane utilized by Dow Chemical Company in the production of chlorine gas and caustic soda, is integral to optimizing its performance. Several factors have been identified as integral components in this effort to optimize the chlorine cell diaphragm. Among these components are the diaphragm's porosity, pore size, thickness and tortuosity. Several methods have been utilized in an effort to determine not only the desired values of each of these variables but also to develop ways of achieving these desired values. Because not all of these variables can be measured directly, other methods of collecting …

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Isolation From Soil Microorganisms That Are Inhibitory To Wheat Seeding Pathogens, Kynita Wilson-Humphrey May 1996

Isolation From Soil Microorganisms That Are Inhibitory To Wheat Seeding Pathogens, Kynita Wilson-Humphrey

McCabe Thesis Collection

Many diseases caused by bacteria, viruses, or fungi are responsible for the ruin of a great number of crops annually. At present, many of these crops are being treated for diseases by synthetic or man-made chemicals. Some of the chemicals have been proved to have adverse effects on the environment, including humans and animals. Very few non-chemical means are available to farmers at this time to control these pathogens. This is due to the fact that many of the means of control have little effect against the pathogens or diseases. This research attempts to isolate microorganisms from the soil which …

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Changing Source Characteristics During Multifragment Decay, T. M. Hamilton, E. Cornell, D. Fox, Y. Lou, R. T. De Souza, M. J. Huang, W. C. Hsi, C. Schwarz, C. Williams, D. R. Bowman, J. Dinius, C. K. Gelbke, T. Glasmacher, D. O. Handzy, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, L. Phair, M. B. Tsang, G. Vanburen, R. J. Charity, L. G. Sobotka, A. A. Sonzogni, D. Prindle May 1996

Changing Source Characteristics During Multifragment Decay, T. M. Hamilton, E. Cornell, D. Fox, Y. Lou, R. T. De Souza, M. J. Huang, W. C. Hsi, C. Schwarz, C. Williams, D. R. Bowman, J. Dinius, C. K. Gelbke, T. Glasmacher, D. O. Handzy, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, L. Phair, M. B. Tsang, G. Vanburen, R. J. Charity, L. G. Sobotka, A. A. Sonzogni, D. Prindle

Faculty Publications

The spatial-temporal extent of the emitting system for central collisions in Kr84 + Au197 at E/A = 35, 55, and 70 MeV is probed using fragment-fragment velocity correlation functions. Selection on fragment pairs of high velocity yields a stronger fragment-fragment Coulomb interaction than for inclusive fragment pairs. This result is consistent with fragment emission from a source of decreased spatial-temporal extent. The universality of this association and the effect of different selection criteria are explored. The sensitivity of the spatial-temporal extent deduced by the correlation function technique to measurement uncertainties, assumed source characteristics, and rotational effects is assessed.

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A Study Of On-Line Analysis Of Hydrogen Chloride Evolution During Coal Combustion, Jennifer Humble May 1996

A Study Of On-Line Analysis Of Hydrogen Chloride Evolution During Coal Combustion, Jennifer Humble

Masters Theses & Specialist Projects

This study involved the use of a thermogravimetric analyzer (TG) interfaced with a fourier transform infrared spectrometer (FTIR) and a mass spectrometer (MS) to determine the evolution of hydrogen chloride from coal during combustion as a function of the chlorine content and mesh size of the coal. It was determined that combined TG-FTIR and TG-MS systems offer the user an efficient means to investigate the mechanism of hydrogen chloride evolution from coal combustion. From the HC1 evolution profiles, it was determined that a good correlation exists between the chlorine content in the coal and the total amount of HC1 evolved. …

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Characterization And Catalytic Properties Of Sulfated Zirconia, Melody Bi May 1996

Characterization And Catalytic Properties Of Sulfated Zirconia, Melody Bi

Masters Theses & Specialist Projects

Sulfated zirconia has attracted extensive attention due to its superactivity to isomerize alkane and alkenes. Platinum or iron/manganese promoted sulfated zirconia has been shown to increase the reaction rate. These catalysts are normally activated to 650-725°C in air before use. Through on-line analysis of evolved gas species during dynamic heating of the catalysts, some significant information can be obtained concerning the activation mechanism. In the present investigation, combined TG-FTIR, TG-MS and TGDTA techniques were utilized to measure the weight loss of the samples, analyze the evolved gas species and to monitor the phase transformation temperature of the solid. Four samples …

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Thermodynamics And Kinetics Of Small Molecule Binding To [Cyclopentadienyl-Ru-No] And [Rh-Co] Electrophilic Centers, Anna Svetlanova May 1996

Thermodynamics And Kinetics Of Small Molecule Binding To [Cyclopentadienyl-Ru-No] And [Rh-Co] Electrophilic Centers, Anna Svetlanova

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This work is concentrated on the thermodynamic and kinetic aspects of water, alcohols, alkyl halides, ethers, and lactones bound and activated by the electrophilic [Cp'Ru(N0)]+2 and [Cp’Ru (NO)(CH3)] + centers (Cp' = cyclopentadienyl group). Counterions in these systems include OSO2CF3- (OTf`) and [(3, 5-(CF3)2C6H3)4B]- ([BAr4']-). The displacement of OTf- in Cp'Ru(N0) (0Tf)2 by H20 in dichloromethane is exothermic but entropically unfavorable due to the required reorganization of the solvent cage around released triflate ions. Thermodynamic parameters are also determined for OTf …

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Influence Of Solvent On The Interfacial Structure Of Self-Assembled Alkanethiol Monolayers, Mark Anderson, Mark Evaniak, Minhui Zhang Apr 1996

Influence Of Solvent On The Interfacial Structure Of Self-Assembled Alkanethiol Monolayers, Mark Anderson, Mark Evaniak, Minhui Zhang

Mark R. Anderson

Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) is used to study the structure of octadecanethiol, tetradecanethiol, and decanethiol monolayers in the presence of air, deuterium oxide, and acetonitrile-d3. It is found that the structure of the monolayer is dependent on both the adjacent environment and the initial structural order of the monolayer. In the D2O solutions, spectral changes are similar for the three monolayers and are characteristic of interaction predominantly between the solvent and the terminal portion of the monolayers. This correlates with electrochemical capacitance measurements that indicate little permeation of the aqueous electrolyte in the monolayer, even with the …

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Development And Evaluation Of Internet-Based Hypermedia Chemistry Tutorials, Brian Tissue, Ronald Earp, Ching-Wan Yip, Mark Anderson Apr 1996

Development And Evaluation Of Internet-Based Hypermedia Chemistry Tutorials, Brian Tissue, Ronald Earp, Ching-Wan Yip, Mark Anderson

Mark R. Anderson

This progress report describes the development and student use of World-Wide-Web-based prelaboratory exercises in senior-level Instrumental Analysis during the 1995 Fall semester. The laboratory preparation exercises contained hypermedia tutorials and multiple-choice questions that were intended to familiarize the students with the experiments and instrumentation before their laboratory session. The overall goal of our work is to explore ways in which computer and network technology can be applied in education to improve the cost-effectiveness and efficacy of teaching. The course material can be accessed at http://www.chem.vt.edu/chem-ed/4114/Fall1995.html.

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Nmr Study Of Neurophysin Dimer Dissociation By Cosolvents, Jian Yao Apr 1996

Nmr Study Of Neurophysin Dimer Dissociation By Cosolvents, Jian Yao

Dissertations and Theses

Neurophysins (NPs) make up a relatively small, stable, and highly soluble class of proteins. They have physiological roles of storage and stabilizing' of peptide hormones oxytocin and vasopression within the posterior pituitary neurosecretory granules. At the concentration of NP found within the granules, NP would exist as a dimer in the absence or presence of bound peptide. The NP monomer-monomer interface involves B-sheet/ B-sheet contact, which can be modulated by the presence of cosolvent. This remarkable feature of NP makes it a model for Alzheimer's disease. One of the characteristics of Alzheimer's disease is the presence of plaques of B-amyloid …

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Critical Pressures In Multicomponent Lipid Monolayers, John P. Hagen, Harden M. Mcconnell Apr 1996

Critical Pressures In Multicomponent Lipid Monolayers, John P. Hagen, Harden M. Mcconnell

Chemistry and Biochemistry

Epifluorescence microscopy has been used previously to study coexisting liquid phases in lipid monolayers of dihydrocholesterol and dimyristoylphosphatidylcholine at the air/water interface. This binary mixture has a critical point at room temperature (22°C), a monolayer pressure of approx. 10 mN/m, and a composition in the vicinity of 20-30 mol% dihydrocholesterol. It is reported here that this critical pressure can be lowered, raised, or maintained constant by systematically replacing molecules of this phosphatidylcholine with molecules of a phosphatidylethanolamine, or an unsaturated phosphatidylcholine, or mixtures of the two, while maintaining the dihydrocholesterol concentration at 20 mol%. Thus, even complex mixtures of lipids …

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Indirect Ultraviolet Detection Of Biologically Relevant Organic Acids By Capillary Electrophoresis, Hong Chen, Yan Xu, Frederick Van Lente, Michael P.C. Ip Apr 1996

Indirect Ultraviolet Detection Of Biologically Relevant Organic Acids By Capillary Electrophoresis, Hong Chen, Yan Xu, Frederick Van Lente, Michael P.C. Ip

Chemistry Faculty Publications

Indirect UV detection of fourteen short-chain organic acids (e.g., oxalic acid, citric acid, malonic acid, tartaric acid, methylmalonic acid, α-ketoglutaric acid, succinic acid, ethylmalonic acid, methylsuccinic acid, glutaric acid, apidic acid, methylglutaric acid, lactic acid and pyruvic acid) by capillary electrophoresis is described. The method used phthalate as the UV-absorbing additive in carbonate buffer and the non-absorbing analytes were detected indirectly at 230 nm. The influences of buffer pH, ionic strenght, concentration of phthalate and organic modifier on indirect signal response and migration behavior of the organic acids were investigated. Comparisons of reproducibility on migration time, limit of detection and …

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Pursuit Of A Chiral Amino Aldehyde Intermediate In The Synthesis Of (+)-Obafluorin, A B-Lactone Antibiotic, Jim Cwik '96 Apr 1996

Pursuit Of A Chiral Amino Aldehyde Intermediate In The Synthesis Of (+)-Obafluorin, A B-Lactone Antibiotic, Jim Cwik '96

Honors Projects

This research is focused on synthesizing a chiral amino aldehyde from L-Serine. The proposed synthesis of the amino aldehyde would yield a stereochemically pure product working through an L-Serine beta-lactone intermediate. The amino aldehyde is a proposed intermediate in the synthesis of (+)-obafluorin, a beta-lactone antibiotic of interest. The proposed synthesis might provide a simpler, more versatile way to synthesize obafluorin.

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The Advanced Glycation End Product, NE-(Carboxymethyl)Lysine, Is A Product Of Both Lipid Peroxidation And Glycoxidation Reactions, Min-Xin Fu, Jesus R. Requena, Alicia J. Jenkins, Timothy J. Lyons, John W. Baynes, Suzanne R. Thorpe Apr 1996

The Advanced Glycation End Product, NE-(Carboxymethyl)Lysine, Is A Product Of Both Lipid Peroxidation And Glycoxidation Reactions, Min-Xin Fu, Jesus R. Requena, Alicia J. Jenkins, Timothy J. Lyons, John W. Baynes, Suzanne R. Thorpe

Faculty Publications

Nepsilon-(Carboxymethyl)lysine (CML) is an advanced glycation end product formed on protein by combined nonenzymatic glycation and oxidation (glycoxidation) reactions. We now report that CML is also formed during metal-catalyzed oxidation of polyunsaturated fatty acids in the presence of protein. During copper-catalyzed oxidation in vitro, the CML content of low density lipoprotein increased in concert with conjugated dienes but was independent of the presence of the Amadori compound, fructoselysine, on the protein. CML was also formed in a time-dependent manner in RNase incubated under aerobic conditions in phosphate buffer containing arachidonate or linoleate; only trace amounts of CML were formed from …

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Toward An Efficient Method Of Detecting Cocaine Metabolite In Urine, C.J. Summers '96 Apr 1996

Toward An Efficient Method Of Detecting Cocaine Metabolite In Urine, C.J. Summers '96

Honors Projects

The primary metabolite of cocaine is benzoyl ecognine (BE). A desirable method for detecting cocaine use is the extraction of BE from urine into an organic phase solvent and subsequent analysis by High Performance Liquid Chromatography (HPLC). The attempt to develop such a method is hindered by the extreme water solubility of BE, making extraction into an organic phase extremely difficult. The present study attempts to use an ion-pairing agent to bind with BE and form a large, organically soluble ion-pair. The ion pairing agent used was Reinecke Salt in a I% solution. An aqueous solution of 50 ug/mL BE …

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Facile Liquid Chromatographic Enantioresolution Of Native Amino Acids And Peptides Using A Teicoplanin Chiral Stationary Phase, Alain Berthod, Youbang Liu, Christina Bagwill, Daniel W. Armstrong Apr 1996

Facile Liquid Chromatographic Enantioresolution Of Native Amino Acids And Peptides Using A Teicoplanin Chiral Stationary Phase, Alain Berthod, Youbang Liu, Christina Bagwill, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

The glycopeptide antibiotic teicoplanin is shown to be a highly effective stationary phase chiral selector for the resolution of underivatized amino-acid and imino-acid enantiomers. Fifty four of these compounds (including all chiral protein amino acids) as well as a number of dipeptides were resolved. Hydro-organic mobile phases are used and no buffers or added salts are needed in most cases. Hence the purified analytes are easily isolated in pure form, if needed, by evaporating of the solvent. The effect of pH, organic modifier type and amount are discussed. The enantioselective separation mechanism is examined using both molecular modeling and retention …

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Site Affinity Of Substituents In Nd₂Fe₁₇₋ₓtₓ (T=Cu,Zr,Nb,Ti,V) Alloys, William B. Yelon, Z. Hu, William Joseph James, G. K. Marasinghe Apr 1996

Site Affinity Of Substituents In Nd₂Fe₁₇₋ₓtₓ (T=Cu,Zr,Nb,Ti,V) Alloys, William B. Yelon, Z. Hu, William Joseph James, G. K. Marasinghe

Physics Faculty Research & Creative Works

In order to understand the magnetic properties of the substituted rare-earth-iron alloys, it is especially important to know the location of the substitutional atoms within the iron lattice. The site distributions of some nontransition-metal substituents in the substituted Nd2Fe17-xTx alloys have previously been reported. Here we report the site distributions of some transition-metal substituents (Cu,Zr,Nb,Ti,V) in the Nd2Fe17-xTx alloys and compare them with those of the nontransition-metal substituted compounds. Rietveld analysis of neutron powder diffraction data indicates that the nontransition-metal substituents show very similar site affinity at low substituent content. …

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Neutron Diffraction And Magnetic Studies Of Rfe₁₂₋ₓtₓcY (R=Y,Er; T=V,Ti,Mo) Alloys, Z. Hu, William B. Yelon, X. D. Zhang, William Joseph James Apr 1996

Neutron Diffraction And Magnetic Studies Of Rfe₁₂₋ₓtₓcY (R=Y,Er; T=V,Ti,Mo) Alloys, Z. Hu, William B. Yelon, X. D. Zhang, William Joseph James

Physics Faculty Research & Creative Works

RFe12-xTxCy, (R=Y,Er; T=V,Ti,Mo) alloys were prepared by rf induction melting and analyzed using neutron powder diffraction and superconducting quantum interference device (SQUID) measurements. Rietveld analysis of the neutron diffraction data indicates that V, Ti, and Mo atoms all prefer the 8i sites. The refined amount of carbon atoms found in the interstitial sites from neutron diffraction data is significantly less than the nominal carbon content. All samples have the easy direction along the c axis. The Er sublattice couples to the Fe sublattice antiferromagnetically. The average Fe site moments range from 1.3 to 2.8 …

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Neutron Diffraction Studies Of Ndₙfeₘ₋ₓ₋YVₓalY [(N,M)=(1,12), (2,17), (3,29)], Z. Hu, William B. Yelon, William Joseph James Apr 1996

Neutron Diffraction Studies Of Ndₙfeₘ₋ₓ₋YVₓalY [(N,M)=(1,12), (2,17), (3,29)], Z. Hu, William B. Yelon, William Joseph James

Physics Faculty Research & Creative Works

Several NdnFem-x-yVxAly [(n,m)=(1,12), (2,17), (3,29)] samples were prepared and analyzed using neutron powder diffraction. Rietveld analysis of the neutron diffraction data indicates that the V and Al substituents take those sites with similar environments in all three phases, as observed in our previous study of Ti-substituted compounds. It was confirmed that the diffraction data of the 3:29 compound can be better refined using the A2/m space group than using the P21/c space group. The SQUID measurements show that all samples have Curie temperatures well above room temperature. The neutron diffraction results …

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Hplc Analysis Of Amino Acid- And Peptide-Derived Chloramines, Thomas Goyne, Jennifer Latham, Suzanne Furness-Green, Tracy Inskeep, Lu Ping, Heather Greenleaf-Schumann Apr 1996

Hplc Analysis Of Amino Acid- And Peptide-Derived Chloramines, Thomas Goyne, Jennifer Latham, Suzanne Furness-Green, Tracy Inskeep, Lu Ping, Heather Greenleaf-Schumann

Thomas Goyne

No abstract provided.

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Circumstantial Evidence For A Critical Behavior In Peripheral Au+Au Collisions At 35 Mev/Nucleon, P. F. Mastinu, M. Belkacem, M. D'Agostino, M. Bruno, P. M. Milazzo, G. Vannini, D. R. Bowman, 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, G. V. Margagliotti, C. P. Montoya, A. Moroni, Graham F. Peaslee, F. Petruzzelli, R. Rui, C. Schwarz, M. B. Tsang, C. Williams, V. Latora, A. Bonasera Apr 1996

Circumstantial Evidence For A Critical Behavior In Peripheral Au+Au Collisions At 35 Mev/Nucleon, P. F. Mastinu, M. Belkacem, M. D'Agostino, M. Bruno, P. M. Milazzo, G. Vannini, D. R. Bowman, 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, G. V. Margagliotti, C. P. Montoya, A. Moroni, Graham F. Peaslee, F. Petruzzelli, R. Rui, C. Schwarz, M. B. Tsang, C. Williams, V. Latora, A. Bonasera

Faculty Publications

The fragmentation resulting from peripheral Au+Au collisions at an incident energy of E=35MeV/nucleon is investigated. A power-law charge distribution, A−τ with τ≈2.2, and an intermittency signal are observed for events selected in the region of the Campi scatter plot where “critical” behavior is expected.

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Β Effect Of Phosphorus Functionalities, Joseph B. Lambert, Yan Zhao Apr 1996

Β Effect Of Phosphorus Functionalities, Joseph B. Lambert, Yan Zhao

Yan Zhao

Diphenylphosphinoyl (−P(O)Ph2) and diphenylthiophosphinoyl (−P(S)Ph2) respectively are modest and strong β-effect functionalities. When these groups are antiperiplanar to mesylate, the substrates solvolyze through unimolecular ionization. In contrast, substrates with the synclinal (gauche) arrangement react bimolecularly with solvent. The anti/gauche rate ratio is 440 for the oxide and 3.2 × 106 for the sulfide at 25 °C. The antiperiplanar sulfide in fact reacts 220 times more rapidly than the analogous cyclohexyl substrate at 25 °C, despite the strong electron-withdrawing nature of diphenylthiophosphinoyl. The α-secondary hydrogen/deuterium kinetic isotope effects of 1.21 for the anti oxide and 1.26 for the anti sulfide suggest …

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Auger Resonant Raman Spectroscopy Used To Study The Angular Distributions Of The Xe 4d5/2 → 6p Decay Spectrum, B. Langer, N. Berrah, A. Farhat, Oliver Hemmers, J. Bozek Apr 1996

Auger Resonant Raman Spectroscopy Used To Study The Angular Distributions Of The Xe 4d5/2 → 6p Decay Spectrum, B. Langer, N. Berrah, A. Farhat, Oliver Hemmers, J. Bozek

Environmental Studies Faculty Publications

The Auger resonant Raman effect can be used as a method to eliminate natural lifetime broadening in resonant Auger spectra. We have coupled this method with high-resolution photons from the Advanced Light Source to study angular distributions and decay rates of the Xe4d5/2→6p resonant Auger lines. The angular distribution parameters β of almost all possible final ionic 5p4(3P, 1D, 1S)6p states have been determined. Our data, which remove the discrepancy between previous lower-resolution experimental results, are compared to different theoretical results.

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