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Full-Text Articles in Physical Sciences and Mathematics
A Mössbauer Effect Study Of The Microscopic Magnetic Properties Of Nd₂Fe₁₇ And Nd₂Fe₁₇N₂.₆, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, K. H. J. Buschow
A Mössbauer Effect Study Of The Microscopic Magnetic Properties Of Nd₂Fe₁₇ And Nd₂Fe₁₇N₂.₆, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, K. H. J. Buschow
Chemistry Faculty Research & Creative Works
The Mössbauer spectra of Nd2Fe17 and Nd 2Fe17N2.6 have been measured at various temperatures between 78 and 295 K and analyzed with a model that is based on the Wigner-Seitz cell environment of each iron site, the orientation of the magnetization, and the magnetic moments as determined from either neutron-diffraction measurements or band-structure calculations. Upon nitrogenation of Nd2Fe17, the weighted average isomer shift increases from 0.060 to 0.164 mm/s and further the isomer shifts of the four crystallographically distinct sites increase in agreement with the increase observed in their …
The Synthesis And Characterization Of Metal Binding Polymers Containing 2,2'-Biimidazole, R. A. Proctor
The Synthesis And Characterization Of Metal Binding Polymers Containing 2,2'-Biimidazole, R. A. Proctor
Opportunities for Undergraduate Research Experience Program (OURE)
Epoxides are known to form ring-opened polymer products that have demonstrated improved material strength, high heat stability, and chemical resistance as adhesives, coatings, and molding materials. It has been suggested that imidazoles can be used in the catalysis of this polymerization, and that the pyridyl nitrogen of the imidazole ring participates in epoxy ring-opening and is then incorporated in the polymeric structure. This study was conducted to test this theory of the role of pyridyl nitrogen in the reaction of 1,1'-dihydroxyethyl-2,2'- biimidazole (HEB) and metal-HEB complexes with the diglycidyl ether of bisphenol A (DGEBA). Of particular interest in this study …
Determining The Chemical Composition Of Cloud Condensation Nuclei, Allen L. Williams, Jane E. Rothert, Kent E. Mcclure, Darryl J. Alofs, Donald E. Hagen, Daniel R. White, A. R. Hopkins, Max B. Trueblood
Determining The Chemical Composition Of Cloud Condensation Nuclei, Allen L. Williams, Jane E. Rothert, Kent E. Mcclure, Darryl J. Alofs, Donald E. Hagen, Daniel R. White, A. R. Hopkins, Max B. Trueblood
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This second progress report describes the status of the project one and one-half years after the start. The goal of the project is to develop the instrumentation to collect cloud condensation nuclei (CCN) in sufficient amounts to determine their chemical composition, and to survey the CCN composition in different climates through a series of field measurements. Our approach to CCN collection is to first form droplets on the nuclei under simulated cloud humidity conditions, which is the only known method of identifying CCN from the background aerosol. Under cloud chamber conditions, the droplets formed become larger than the surrounding aerosol, …
Mössbauer And Neutron Diffraction Studies Of Y₂(Fe₁₋ₓmnₓ)₁₄B, Oran Allan Pringle, Gaya Kanishka Marasinghe, Gary J. Long, William Joseph James, William B. Yelon, Decai Xie, Fernande Grandjean
Mössbauer And Neutron Diffraction Studies Of Y₂(Fe₁₋ₓmnₓ)₁₄B, Oran Allan Pringle, Gaya Kanishka Marasinghe, Gary J. Long, William Joseph James, William B. Yelon, Decai Xie, Fernande Grandjean
Physics Faculty Research & Creative Works
We have used Mössbauer spectroscopy and neutron diffraction to study a series of Y2(Fe1-xMnx)1 4B samples in the composition range from x=0.0 to 0.4. Y 2(Fe0.6Mn0.4)14B is paramagnetic at both room temperature and 85 K. The iron quadrupole splitting in this paramagnetic compound allows us to place an upper limit on the quadrupole shift in the magnetic Y2(Fe1-xMnx) 14B alloys. Refinement of Y2(Fe 1-xMnx)14B neutron diffraction data have been used to …
Fundamental Aspect And Behavior Of Saturated Fluorocarbons In Glow Discharge In Absence Of Potential Source Of Hydrogen, Yu Iriyama, H. Yasuda
Fundamental Aspect And Behavior Of Saturated Fluorocarbons In Glow Discharge In Absence Of Potential Source Of Hydrogen, Yu Iriyama, H. Yasuda
Chemistry Faculty Research & Creative Works
The glow discharge of a series of saturated fluorocarbons, CnF2n+2 (n = 1, 2, 4, 6, and 8), was studied with glass substrates which do not contain any hydrogen. It was found that the deposition rate was a function of the F/C ratio of the starting fluorocarbons. That is, fluorocarbons with higher F/C ratio, such as CF4 and C2F6, hardly polymerized, while fluorocarbons with lower F/C ratio, such as C8F18, polymerized as well as C2F4. After plasma exposure, the surface of glass substrate was …
Empirical Procedure That Uses Molecular Structure To Predict Enantioselectivity Of Chiral Stationary Phases, Alain Berthod, San Chun Chang, Daniel W. Armstrong
Empirical Procedure That Uses Molecular Structure To Predict Enantioselectivity Of Chiral Stationary Phases, Alain Berthod, San Chun Chang, Daniel W. Armstrong
Chemistry Faculty Research & Creative Works
A total of 121 racemic compounds were separated In the normal-phase mode on a (S)-(1-naphthylethyl)carbamoylated β-cyclodextrin (S-NEC-β-CD) bonded phase and 74 on the R equivalent (-NEC) chiral stationary phase (CSP). All compounds are of the type that have four substituents on a stereogenlc center, rather than an "axis of chirality". It is shown that the binary solvent pair used as the mobile phase has a significant Influence on chiral recognition. However, the proportions of the components of a specific pair have little effect. From the results, the Individual contributions to chiral recognition by these CSPs were estimated for 81 different …
Multiple Enantioselective Retention Mechanisms On Derivatized Cyclodextrin Gas Chromatographic Chiral Stationary Phases, Alain Berthed, Weiyong Li, Daniel W. Armstrong
Multiple Enantioselective Retention Mechanisms On Derivatized Cyclodextrin Gas Chromatographic Chiral Stationary Phases, Alain Berthed, Weiyong Li, Daniel W. Armstrong
Chemistry Faculty Research & Creative Works
2, 6-Di-O-pentyl-3-O-(trifluoroacetyl) (DP-TFA) derivatized β and γ-cyclodextrlne are able to resolve a wide variety of volatile racemic compounds. The enantiomeric recognition mechanism of these phases was Investigated. The retention behavior of homologous series showed that lengthening the side alkyl chain Increases the retention time but does not affect enantioselectivlty. The thermodynamic parameters, free energy, enthalpy, and the difference In free energy, enthalpy, and entropy between enantiomers were evaluated for 24 enantiomeric pairs. From this data, It appears that the compounds can be arranged In two groups. One group has high values for enthalpy, entropy, free energy, and the corresponding difference …
1-Ferrocenyl-1-Cyclopropyl Cation: The First Long-Lived Cyclopropyl Cation, G. K.Surya Prakash, Herwig Buchholz, V. Prakash Reddy, Armin De Meijere, George A. Olah
1-Ferrocenyl-1-Cyclopropyl Cation: The First Long-Lived Cyclopropyl Cation, G. K.Surya Prakash, Herwig Buchholz, V. Prakash Reddy, Armin De Meijere, George A. Olah
Chemistry Faculty Research & Creative Works
No abstract provided.
Hydration Behavior Of Laser Dye Aerosols Of Mixed Composition Having High Critical Supersaturations, Max B. Trueblood, Donald E. Hagen, Darryl J. Alofs
Hydration Behavior Of Laser Dye Aerosols Of Mixed Composition Having High Critical Supersaturations, Max B. Trueblood, Donald E. Hagen, Darryl J. Alofs
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This Study Concerns Aerosol Particles of Mixed Composition. the Particles Contain a Water Insoluble Core (Polystyrene Latex), Surrounded by a Water Soluble Shell (Various Fluorescent Dyes). a Collison Nebulizer and an Electrostatic Aerosol Classifier Are Used to Prepare the Aerosol; its Critical Supersaturation Spectrum is Measured with a Diffusion Cloud Chamber. Experiments Were Done using Four Different Dyes (Disodium Fluorescein, Sulforhodamine 640, Sulforhodamine B and Rhodamine 560 Chloride) with Five Different Polystyrene Latex Sphere Sizes. the Results Indicate that a Kohler-Type Behavior is Obeyed. This Technique of Putting a Soluble Coating Onto an Insoluble Core is Found to Be a …
Structural Studies Of Rare Earth-Iron Nitrides By Neutron Powder Diffraction, William B. Yelon, George C. Hadjipanayis
Structural Studies Of Rare Earth-Iron Nitrides By Neutron Powder Diffraction, William B. Yelon, George C. Hadjipanayis
Physics Faculty Research & Creative Works
No abstract provided.
Magnetic Properties Of A Novel Iron Carbide Film, Fe₇C₃X Formed In A Glow Discharge, Oran Allan Pringle, Gary J. Long, Fernande Grandjean, Jun L. Li, George C. Hadjipanayis, William Joseph James
Magnetic Properties Of A Novel Iron Carbide Film, Fe₇C₃X Formed In A Glow Discharge, Oran Allan Pringle, Gary J. Long, Fernande Grandjean, Jun L. Li, George C. Hadjipanayis, William Joseph James
Physics Faculty Research & Creative Works
No abstract provided.
Thalamic Stroke: Presentation And Prognosis Of Infarcts And Hemorrhages, Wolfgang Steinke, Ralph L. Sacco, J. P. Mohr, Mary A. Foulkes, Thomas K. Tatemichi, Philip A. Wolf, Thomas R. Price, Daniel B. Hier
Thalamic Stroke: Presentation And Prognosis Of Infarcts And Hemorrhages, Wolfgang Steinke, Ralph L. Sacco, J. P. Mohr, Mary A. Foulkes, Thomas K. Tatemichi, Philip A. Wolf, Thomas R. Price, Daniel B. Hier
Chemistry Faculty Research & Creative Works
Thalamic Strokes in 62 Patients Selected from the Stroke Data Bank Were Studied to Determine Differences among 18 Infarctions (INF), 23 Localized Hemorrhages (ICH), and 21 Hematomas with Ventricular Extension (IVH). Stupor or Coma at Onset Occurred More Frequently in the IVH (62%) Than in the INF (6%) or ICH (13%) Groups and Was Reflected in Significantly Lower Median Glasgow Coma Scores in the IVH Group (7) Than in the INF (15) and ICH (14) Groups. Although Ocular Movements Were More Frequently Abnormal in the IVH Group Compared with the ICH and INF Groups, No Significant Differences Were Found in …
Early Clinical Differentiation Of Cerebral Infarction From Severe Atherosclerotic Stenosis And Cardioembolism, S. G. Timsit, R. L. Sacco, J. P. Mohr, M. A. Foulkes, T. K. Tatemichi, P. A. Wolf, T. R. Price, D. (Daniel) B. Hier
Early Clinical Differentiation Of Cerebral Infarction From Severe Atherosclerotic Stenosis And Cardioembolism, S. G. Timsit, R. L. Sacco, J. P. Mohr, M. A. Foulkes, T. K. Tatemichi, P. A. Wolf, T. R. Price, D. (Daniel) B. Hier
Chemistry Faculty Research & Creative Works
Background and Purpose: Hyperacute Cerebral Infarction Trials Require Early Differentiation of Infarction Subtype. Our Aim Was to Determine Clinical Factors Predictive of Infarction Subtype from Data Collected in the Early Hours of Admission. Methods: using the 1,273 Patients Enrolled in the Stroke Data Bank, Stroke Risk Factors and Demographic, Clinical, and Radiological Features Were Compared between the 246 Cardioembolic and 113 Large-Vessel Atherosclerotic Cerebral Infarcts. Results: Stroke Data Bank Definitions Ensured More Transient Ischemic Attacks in Atherosclerotic Infarcts and More Cardiac Disease in Cardioembolic Infarcts, But the Diagnosis Was Distinguished Further using a Logistic Regression Model. Fractional Arm Weakness (Shoulder …