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Articles 3511 - 3540 of 3783

Full-Text Articles in Physical Sciences and Mathematics

Solid-State Nmr Characterization Of Organics In Cement, Michael A. Janusa Jan 1992

Solid-State Nmr Characterization Of Organics In Cement, Michael A. Janusa

Faculty Publications

Solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) has been applied to cement samples containing water-soluble organics, ethylene glycol, phenol, p­bromophenol and p-chlorophenol. Cement matrix development has been followed by 29Si and27Al NMR, which shows the organics, particularly ethylene glycol, to be promoters of silicate polymerization despite the fact that they reduce the compressive strength of the pastes. 13C NMR shows that phenol is completely ionized in cement pastes, but with substituted phenols in the presence of extra added metal salts, ionization is not always complete. 2H NMR on d5 …

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Slip Length In A Dilute Gas, Alejandro Garcia, D. Morris, L. Hannon Jan 1992

Slip Length In A Dilute Gas, Alejandro Garcia, D. Morris, L. Hannon

Faculty Publications

We study the phenomenon of slip length using molecular dynamics and direct simulation Monte Carlo simulations of a dilute gas. Our work extends the range of Knudsen numbers that have been previously studied. In a recent paper, Bhattacharya and Lie [Phys. Rev. 43, 761 (1991)] suggest a logarithmic dependence of slip length on Knudsen number. By a simple redefinition of the mean free path, we obtain good agreement between simulation results and Maxwell theory for slip length. The anomalies seen by Bhattacharya and Lie appear to be due to their definition of the mean free path.

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Stable Isotope Analysis Using Tunable Diode Laser Spectroscopy, Todd B. Sauke, J. F. Becker, M. Loewenstein Jan 1992

Stable Isotope Analysis Using Tunable Diode Laser Spectroscopy, Todd B. Sauke, J. F. Becker, M. Loewenstein

Faculty Publications

Measurements of ratios of stable isotopes are used in such diverse fields as petroleum prospecting, medical diagnostics, and planetary exploration. The narrow emission linewidth available from tunable diode lasers permits high-resolution infrared absorption measurements of closely spaced isotopic rovibrational lines. Our dual beam spectrometer uses the sweep integration technique in a spectral region where adjacent spectral lines are of approximately equal absorbance at the expected isotopic abundances. The experimental results reported here indicate that isotopic ratios of carbon in carbon dioxide can be measured to an accuracy of better than 0.4%. This laser spectroscopic spectrometric technique offers an alternative to …

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A Modular Array To Detect Complex Fragments Produced In Intermediate-Energy Reverse-Kinematics Reactions, W. L. Kehoe, A. C. Mignerey, A. Moroni, I. Iori, Graham F. Peaslee, N. Colonna, K. Hanold, K. Hanold, D. R. Bowman, L. G. Moretto, M. A. Mcmahan, J. T. Walton, G. J. Wozniak Jan 1992

A Modular Array To Detect Complex Fragments Produced In Intermediate-Energy Reverse-Kinematics Reactions, W. L. Kehoe, A. C. Mignerey, A. Moroni, I. Iori, Graham F. Peaslee, N. Colonna, K. Hanold, K. Hanold, D. R. Bowman, L. G. Moretto, M. A. Mcmahan, J. T. Walton, G. J. Wozniak

Faculty Publications

A segmented silicon-silicon-plastic array was constructed for studying complex fragment production in heavy-ion reactions with incident energies of 35–100 MeV/u. The array was designed: (1) to measure the energy, position and charge of fragments with 1≤Z≤Zproj; (2) to have high efficiency for detecting fragments produced in reverse-kinematics reactions; (3) to detect events with two or more fragments; and (4) to have a flexible configuration. Each array telescope consists of a 300 μm Si detector, a 5 mm Si(Li) detector and a 7.6 cm plastic scintillator. The elements of the telescope are held by interconnecting modular packages which allow the telescopes …

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Real And Virtual Images Using A Classroom Hologram, Dale W. Olson Jan 1992

Real And Virtual Images Using A Classroom Hologram, Dale W. Olson

Faculty Publications

No abstract provided.

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Removal Of Mercury From Waste Water: Large-Scale Performance Of An Ion Exchange Process, James A. Ritter, J. P. Bibler Jan 1992

Removal Of Mercury From Waste Water: Large-Scale Performance Of An Ion Exchange Process, James A. Ritter, J. P. Bibler

Faculty Publications

Duolite™ GT-73 ion exchange resin routinely reduces the mercury content of a waste water stream to less than the permitted level of 10 ppb. Effluent concentrations from the ion exchange facility (IEF) are consistently between 1 to 5 ppb, even though the feed contains a varying concentration of mercury (0.2 to 70 ppm). Two operational problems have been encountered at that facility, however. Firstly, the stated capacity of the resin for mercury was not being achieved. The abnormally low capacity was traced to analytical laboratory waste which was intermittently treated by the resin. That waste contained hydrochloric acid, stannous chloride, …

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X-Ray Diode Using A Silicon Field Emission Photocathode, W. I. Karian, Larry V. Knight, David D. Allred, A. Reyes-Mena Jan 1992

X-Ray Diode Using A Silicon Field Emission Photocathode, W. I. Karian, Larry V. Knight, David D. Allred, A. Reyes-Mena

Faculty Publications

We have produced arrays of 10,000 sharp p-type silicon points using an etch plus oxidation method. The points were used as electron emitters. No high vacuum cesiation or high temperature cleaning was needed to observe the electron emission. These are seen to be photosensitive sources of electrons at 200 K and 300 K. They were also used to produce AlKα x-rays. This constitutes the first use of etched, point arrays for generating electrons for x-ray sources.

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Characterization Of As-Prepared And Annealed W/C Multilayer Thin Films, David D. Allred, Qi Wang, Jesus González-Hernández, B. S. Chao, D. A. Pawlik Jan 1992

Characterization Of As-Prepared And Annealed W/C Multilayer Thin Films, David D. Allred, Qi Wang, Jesus González-Hernández, B. S. Chao, D. A. Pawlik

Faculty Publications

Tungsten/carbon (W/C) multilayer thin films were prepared by dc magnetron sputtering. All samples consisted of 30 layer pairs with a nominal d-spacing varying from 2.5 to 14 nm, the W layer thickness was kept at 2 nm in all samples. The W/C multilayers were subjected to isochronal anneals in a quartz tube furnace at the temperature range from 500 to 950 °C under a flow of high purity Ar gas. X-ray diffraction, Raman scattering, and Auger depth profile were used to characterize the structure of the as-prepared and annealed multilayer films. Both the W and C layers appear to be …

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Manufacturing Of Atomically Sharp Silicon Tips And Their Use As Photocathodes, W. I. Karian, Larry V. Knight, David D. Allred, A. Reyes-Mena Jan 1992

Manufacturing Of Atomically Sharp Silicon Tips And Their Use As Photocathodes, W. I. Karian, Larry V. Knight, David D. Allred, A. Reyes-Mena

Faculty Publications

The discovery and understanding of the photoelectric effect led to the study of photoemissive materials fall into two major categories: classical photoemitters and negative-electron-affinity (NEA) materials. Classical photoemitters usually involve an alkali metal, a group-V element such as phosphorus, silver, and/or oxygen. An example is the Ag-O-Cs (S1) photoemitter. NEA photocathodes consist of a photoconductive single crystal semiconductor covered with a thin layer of cesium and oxygen. This layer lowers the work function of the photocathode. A dipole layer is formed at the surface, and band bending occurs. This lowers the effective work function. An example is the GaAs(CsO) photocathode …

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Characterizations Of Antimony Tri‐Sulfide Chemically Deposited With Silicotungstic Acid, O. Savadogo, K. C. Mandal Jan 1992

Characterizations Of Antimony Tri‐Sulfide Chemically Deposited With Silicotungstic Acid, O. Savadogo, K. C. Mandal

Faculty Publications

No abstract provided.

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A Family Of Complexes Associated To An Almost Alternating Map, With Applications To Residual Intersections, Andrew R. Kustin, Bernd Ulrich Jan 1992

A Family Of Complexes Associated To An Almost Alternating Map, With Applications To Residual Intersections, Andrew R. Kustin, Bernd Ulrich

Faculty Publications

No abstract provided.

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Magnetic Response Of A Single, Isolated Gold Loop, V. Chandrasekhar, Richard A. Webb, M. J. Brady, M. B. Ketchen, W. J. Gallagher, A. Kleinsasser Dec 1991

Magnetic Response Of A Single, Isolated Gold Loop, V. Chandrasekhar, Richard A. Webb, M. J. Brady, M. B. Ketchen, W. J. Gallagher, A. Kleinsasser

Faculty Publications

Measurements have been made of the low-temperature magnetic response of single, isolated, micron-size Au loops. The magnetic response is found to contain a component which oscillates with the applied magnetic flux with a fundamental period of Φ0=h/e. The amplitude of the oscillatory component corresponds to a persistent current of ≃(0.3–2.0)evF/L, 1 to 2 orders of magnitude larger than predicted by current theories.

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Mass Asymmetric Fission Barriers For 75br, D. N. Delis, Y. Blumenfeld, D. R. Bowman, N. Colonna, K. Hanold, K. Jing, M. Justice, J. C. Meng, Graham F. Peaslee, G. J. Wozniak, L. G. Moretto Nov 1991

Mass Asymmetric Fission Barriers For 75br, D. N. Delis, Y. Blumenfeld, D. R. Bowman, N. Colonna, K. Hanold, K. Jing, M. Justice, J. C. Meng, Graham F. Peaslee, G. J. Wozniak, L. G. Moretto

Faculty Publications

Fragments with atomic numbers covering nearly the entire range of the mass-asymmetry coordinate (4 < Z < 27) were observed from the 5.0, 6.2, 6.9, 8.0, 10.2 and 12.7 MeV/A 63Cu + 12C reactions. Energy spectra and angular distributions show the presence of projectile-like and target-like components along with an isotropic component. The isotropic component appears as a Coulomb ring in the invariant cross-section plots indicating the presence of a binary compound nucleus decay which is confirmed by the coincidence data. Excitation functions were constructed for each Z value and a nearly complete set of mass-asymmetric barriers has been extracted for 75Br. There is excellent agreement between the experimentally determined barriers and the finite-range model predictions.

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Single-Electron Charging Effects In Insulating Wires, Venkat Chandrasekhar, Zvi Ovadyahu, Richard A. Webb Nov 1991

Single-Electron Charging Effects In Insulating Wires, Venkat Chandrasekhar, Zvi Ovadyahu, Richard A. Webb

Faculty Publications

We present measurements of the transport properties of 0.75-μm-long, narrow, insulating indium oxide wires and rings. These devices have no apparent tunnel barriers, yet they exhibit effects similar to those found in series arrays of very small-capacitance tunnel junctions: highly nonlinear I-V characteristics and a zero-bias conductance which is periodic in a voltage applied by means of a lateral gate. These effects are due to the influence of single-electron charging on transport through localized states in the insulating regime.

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The Effect Of A Tilted Magnetic Field On The Equilibrium Of A Pure Electron Plasma, Grant W. Hart Nov 1991

The Effect Of A Tilted Magnetic Field On The Equilibrium Of A Pure Electron Plasma, Grant W. Hart

Faculty Publications

If the magnetic field in a pure electron plasma containment device is not aligned with the axis of the conducting walls, the electrons in the device will accumulate at the ends of the plasma where the magnetic field lines come closest to the walls and the electrons bound to the field lines can be closest to their image charges. If the plasma is also offset radially from the center (as with an l=1 diocotron mode), then more density will accumulate at one end than the other. As the plasma revolves around the center, the electrons will slosh from one end …

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Multifragment Emission In The Reaction 36ar + 197au At E/A = 35, 50, 80, And 110 Mev, R. T. De Souza, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Yim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, H. M. Tsang, H. M. Xu, F. Zhu, W. A. Friedman Oct 1991

Multifragment Emission In The Reaction 36ar + 197au At E/A = 35, 50, 80, And 110 Mev, R. T. De Souza, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Yim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, H. M. Tsang, H. M. Xu, F. Zhu, W. A. Friedman

Faculty Publications

Multifragment emission in the reaction at has been measured with a low-threshold 4π detector array. Over this broad range of incident energies, the mean values and variances of the intermediate mass fragment (IMF: 3 ⩽ Z ⩽ 20) multiplicity distributions exhibit an approximate scaling with the total charged particle multiplicity. The measured multiplicities of light charged particles and intermediate mass fragments are compared with both a model involving statistical decay of an expanding compound nucleus, and with a model involving microscopic quasi-particle dynamics. The statistical decay model predictions are sensitive to the low-density nuclear equation of state.

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Multifragment Disintegration Of The Xe+Au System At E/A=50 Mev, D. R. Bowman, Graham F. Peaslee, R. T. De Souza, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Yim, M. A. Lisa, W. G. Lynch, L. Phair, M. B. Tsang, C. Williams, C. Williams, N. Colonna, K. Hanold, M. A. Mcmahan, G. J. Wozniak, L. G. Moretto, W. A. Friedman Sep 1991

Multifragment Disintegration Of The Xe+Au System At E/A=50 Mev, D. R. Bowman, Graham F. Peaslee, R. T. De Souza, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Yim, M. A. Lisa, W. G. Lynch, L. Phair, M. B. Tsang, C. Williams, C. Williams, N. Colonna, K. Hanold, M. A. Mcmahan, G. J. Wozniak, L. G. Moretto, W. A. Friedman

Faculty Publications

Multifragment disintegrations following Xe129+197Au collisions at E/A=50 MeV have been studied with a multidetector system covering 88% of 4π in solid angle. The average number of intermediate-mass fragments (Z=3–20) increases strongly as a function of charged-particle multiplicity and reaches values larger than six for the most violent collisions. The results are compared to calculations with both dynamical and statistical models.

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A Self-Organizing Binary Decision Tree For Incrementally Defined Rule-Based Systems, Douglas M. Campbell, Tony R. Martinez Sep 1991

A Self-Organizing Binary Decision Tree For Incrementally Defined Rule-Based Systems, Douglas M. Campbell, Tony R. Martinez

Faculty Publications

This paper presents an adaptive self-organizing concurrent system (ASOCS) model for massively parallel processing of incrementally defined rule systems in such areas as adaptive logic, robotics, logical inference, and dynamic control. An ASOCS is an adaptive network composed of many simple computing elements operating asynchronously and in parallel. This paper focuses on adaptive algorithm 3 (AA3) and details its architecture and learning algorithm. It has advantages over previous ASOCS models in simplicity, implementability, and cost. An ASOCS can operate in either a data processing mode or a learning mode. During the data processing mode, an ASOCS acts as a parallel …

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Formation Of Pentosidine During Nonenzymatic Browning Of Proteins By Glucose, Daniel G. Dyer, James A. Blackledge, Suzanne R. Thorpe, John W. Baynes Jun 1991

Formation Of Pentosidine During Nonenzymatic Browning Of Proteins By Glucose, Daniel G. Dyer, James A. Blackledge, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

A fluorescent compound has been detected in proteins browned during Maillard reactions with glucose in vitro and shown to be identical to pentosidine, a pentose- derived fluorescent cross-link formed between arginine and lysine residues in collagen (Sell, D. R., and Monnier, V. M. (1989) J. Biol. Chem. 264, 21597- 2 1602). Pentosidine was the major fluorophore formed during nonenzymatic browning of ribonuclease and lysozyme by glucose, but accounted for <1% of nondisulfide cross-links in protein dimers formed during the reaction. Pentosidine was formed in greatest yields in reactions of pentoses with lysine and arginine in model systems but was also formed from glucose, fructose, ascorbate, Amadori compounds, 3-deoxyglucosone, and other sugars. Pentosidine was not formed from peroxidized polyunsaturated fatty acids or malondialdehyde. Its formation from carbohydrates was inhibited under nitrogen or anaerobic conditions and by aminoguanidine, an inhibitor of advanced glycation and browning reactions. Pentosidine was detected in human lens proteins, where its concentration increased gradually with age, but it did not exceed trace concentrations (55 Fmol/mol lysine), even in the 80-year-old lens. Although its precise carbohydrate source in vivo is uncertain and it is present in only trace concentrations in tissue proteins, pentosidine appears to be a useful biomarker for assessing cumulative damage to proteins by nonenzymatic browning reactions with carbohydrates.

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Multifragment Disintegrations Of The 36ar + 197au Systems At E/A=35-110 Mev , Y. D. Kim, R. T. De Souza, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, C. Williams, F. Zhu, W. A. Friedman, S. Pratt Jun 1991

Multifragment Disintegrations Of The 36ar + 197au Systems At E/A=35-110 Mev , Y. D. Kim, R. T. De Souza, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, C. Williams, F. Zhu, W. A. Friedman, S. Pratt

Faculty Publications

Intermediate mass fragment (IMF: 3≤Z≤20) emission for the 36Ar+197 Au reaction at E/A=35, 50, 80, 110 MeV has been studied with a low‐threshold 4π charged‐particle detector array. Multiplicities of intermediate mass fragments gated on total charged‐particle multiplicities have been extracted with an average multiplicity of 4 intermediate mass fragments for the most central collisions at E/A=110 MeV. Two‐fragment correlation functions are presented for various gates on the fragment energy, and information about the time‐scale of fragment emission is extracted.

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Decrease In Skin Collagen Glycation With Improved Glycemic Control In Patients With Insulin-Dependent Diabetes Mellitus, Timothy J. Lyons, Karen E. Bailie, Daniel G. Dyer, John A. Dunn, John W. Baynes Jun 1991

Decrease In Skin Collagen Glycation With Improved Glycemic Control In Patients With Insulin-Dependent Diabetes Mellitus, Timothy J. Lyons, Karen E. Bailie, Daniel G. Dyer, John A. Dunn, John W. Baynes

Faculty Publications

Glycation, oxidation, and nonenzymatic browning of protein have all been implicated in the development of diabetic complications. The initial product of glycation of protein, fructoselysine (FL), undergoes further reactions, yielding a complex mixture of browning products, including the fluorescent lysine-arginine cross-link, pentosidine. Alternatively, FL may be cleaved oxidatively to form N(epsilon)-(carboxymethyl)lysine (CML), while glycated hydroxylysine, an amino-acid unique to collagen, may yield N(epsilon)-(carboxymethyl)hydroxylysine (CMhL). We have measured FL, pentosidine, fluorescence (excitation = 328 nm, emission = 378 nm), CML, and CMhL in insoluble skin collagen from 14 insulin-dependent diabetic patients before and after a 4-mo period of intensive therapy to …

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A Complete Ridge-Line Potential For Complex Fragment Emission, D. N. Delis, Y. Blumenfeld, D. R. Bowman, N. Colonna, K. Hanold, K. Jing, M. Justice, J. C. Meng, Graham F. Peaslee, G. J. Wozniak, L. G. Moretto Jun 1991

A Complete Ridge-Line Potential For Complex Fragment Emission, D. N. Delis, Y. Blumenfeld, D. R. Bowman, N. Colonna, K. Hanold, K. Jing, M. Justice, J. C. Meng, Graham F. Peaslee, G. J. Wozniak, L. G. Moretto

Faculty Publications

Cross sections were measured for fragments (4

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Transport Properties Of An Interacting Lattice Gas Model In A Charge Density Gradient By Monte Carlo Simulation, Ras B. Pandey, Songping Gao Apr 1991

Transport Properties Of An Interacting Lattice Gas Model In A Charge Density Gradient By Monte Carlo Simulation, Ras B. Pandey, Songping Gao

Faculty Publications

A two-dimensional lattice is considered with a linear charge-density gradient produced by a charge source at one end and a sink at the opposite end. A fraction p of the lattice sites are occupied by mobile particles that interact only with neighboring particles and empty sites (the substrate) and carry charges from source to sink; the charge neutrality of the whole lattice is maintained. The root-mean-square (rms) displacement of the particles (i.e., the tracers) and their effective conductivity for the charge transport are studied as a function of temperature and concentration p. The rms displacement shows a crossover from diffusion …

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Theory Of An Atomic Beam Splitter Based On Velocity-Tuned Resonances, Scott Glasgow, P. Meystre, M. Wilkens, E. M. Wright Mar 1991

Theory Of An Atomic Beam Splitter Based On Velocity-Tuned Resonances, Scott Glasgow, P. Meystre, M. Wilkens, E. M. Wright

Faculty Publications

We develop the theory of an atomic beam splitter in which a monoenergetic beam of two-level atoms is incident normally to a classical standing-wave light field. The incident atomic wave function can be split into two coherent components with transverse momenta ±(2n + 1)fzk using velocity-tuned resonances, where n is the order of the resonance. We discuss the cases of zero- and first-order resonances in detail, and show that the velocity-tuned resonances are renormalized due to a high-frequency Stark shift. Numerical results that display the effects of a finite momentum spread in the incident atomic beam are presented.

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The Analysis Of A Model For Wave Motion In A Liquid Semiconductor: Boundary Interaction And Variable Conductivity, William V. Smith Mar 1991

The Analysis Of A Model For Wave Motion In A Liquid Semiconductor: Boundary Interaction And Variable Conductivity, William V. Smith

Faculty Publications

The theory of conducting fluids in relative motion with small conductivity is studied with a model including the Maxwell displacement current. The model is linearized, and the interaction of waves with a plane boundary in three space is studied for two orientations of the external magnetic field. It is found that two families of boundary conditions preserve energy in one orientation (external field orthogonal to the boundary), while in the other (external field parallel to the boundary) only one condition exists which preserves energy. It is shown that generalized Fourier transforms exist, generated from the generalized eigenfunction expansions. Further, it …

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Equilibrium And Non-Equilibrium Complex Fragment Emission In 50-100 Mev/U 139la + 12c Reactions, D. R. Bowman, Graham F. Peaslee, N. Colonna, R. J. Charity, M. A. Mcmahan, D. Delis, H. Han, K. Jing, G. J. Wozniak, L. G. Moretto, W. L. Kehoe, B. Libby, A. C. Mignerey, A. Moroni, S. Angius, I. Iori, A. Pantaleo, G. Guarino Feb 1991

Equilibrium And Non-Equilibrium Complex Fragment Emission In 50-100 Mev/U 139la + 12c Reactions, D. R. Bowman, Graham F. Peaslee, N. Colonna, R. J. Charity, M. A. Mcmahan, D. Delis, H. Han, K. Jing, G. J. Wozniak, L. G. Moretto, W. L. Kehoe, B. Libby, A. C. Mignerey, A. Moroni, S. Angius, I. Iori, A. Pantaleo, G. Guarino

Faculty Publications

Complex fragment emission (Z > 2) has been studied in the reactions of 50, 80, and 100 MeV/u139La + 12C. Charge, angle, and energy distributions were measured inclusively and in coincidence with other complex fragments, and were used to extract source rapidities, velocity distributions, and cross sections. The binary signature of the coincidence events and the sharpness of the velocity distributions illustrate the primarily 2-body nature of these reactions. Calculations based on statistical compound nucleus decay have been compared with the experimental data. The emission velocities, angular distributions, and absolute cross sections of fragments of 20 ⩽ Z ⩽ 35 at …

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Multifragment Events From Heavy-Ion Collisions: Sources And Excitation Functions, Y. Blumenfeld, N. Colonna, P. Roussel-Chomaz, D. N. Delis, K. Hanold, J. C. Meng, Graham F. Peaslee, Q. C. Sui, G. J. Wozniak, L. G. Moretto, B. Libby, A. C. Mignerey, G. Guarino, N. Santoruvo, I. Iori Feb 1991

Multifragment Events From Heavy-Ion Collisions: Sources And Excitation Functions, Y. Blumenfeld, N. Colonna, P. Roussel-Chomaz, D. N. Delis, K. Hanold, J. C. Meng, Graham F. Peaslee, Q. C. Sui, G. J. Wozniak, L. G. Moretto, B. Libby, A. C. Mignerey, G. Guarino, N. Santoruvo, I. Iori

Faculty Publications

Multifragment events from 35, 40, 45, and 55 MeV/nucleon La139+12C, Al27, Ca40, V51, Cunat, and La139 reactions can be assigned to sources characterized by their velocity. At each bombarding energy, the probabilities of threefold, fourfold and fivefold events increase substantially with decreasing source velocity, but are independent of the target mass. To remove the bombarding-energy dependence, a simple transformation has been applied which gives the excitation energy of the fused system in the simple incomplete-fusion picture. These ‘‘excitation functions’’ appear to independent of both the system and bombarding energy.

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Simultaneous Light And Radial Velocity Curve Solutions For U Cephei, J. B. Rafert, N. L. Markworth Jan 1991

Simultaneous Light And Radial Velocity Curve Solutions For U Cephei, J. B. Rafert, N. L. Markworth

Faculty Publications

The light-curve synthesis approach of Wilson & Devinney has been used to solve simultaneously light and radial velocity curves of the Algol-type eclipsing binary star U Cephei. We have performed eight new differential corrections solutions using the photometric data of Markworth and the radial velocity data of Batten to obtain a consistent set of orbital and astrophysical parameters for the light and velocity curves of this famous system. We find U Cephei to be best modeled using the semidetached (mode 5) system geometry of the Wilson & Devinney program, with a primary rotating at about 5.2 times its synchronous rate, …

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X-Ray Study Of The Crystallization Processes In Amorphous (Zro. 64ni0. 36) 1-Xalx Alloys. [Abstract], W. D. Bruton, T. O. Callaway, Richard H. Langley, B. H. Zhang, D. G. Naugle Jan 1991

X-Ray Study Of The Crystallization Processes In Amorphous (Zro. 64ni0. 36) 1-Xalx Alloys. [Abstract], W. D. Bruton, T. O. Callaway, Richard H. Langley, B. H. Zhang, D. G. Naugle

Faculty Publications

The short range order in (Zr0.64Ni0.36)1−xAlx metallic glasses for values of x between 0 and 0.25 was investigated using X-ray diffraction. X-ray intensity patterns and the derived structural functions for the as-quenched samples differed only slightly with the change in aluminum concentration, suggesting that the addition of aluminum does not significantly alter the relative coordination of the zirconium and nickel atoms. Only the first two alloys in the series (x = 0, 0.05) exhibited multiple transitions in the DSC thermograms. The intermediate phase for the x = 0.05 alloy has an …

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Nonequilibrium Processes In Polymers Undergoing Interchange Reactions. Part 2: Reaction-Diffusion Processes, Alejandro Garcia, J. Pojman, D. Kondepudi, C. Van De Broeck Jan 1991

Nonequilibrium Processes In Polymers Undergoing Interchange Reactions. Part 2: Reaction-Diffusion Processes, Alejandro Garcia, J. Pojman, D. Kondepudi, C. Van De Broeck

Faculty Publications

A reactiodffusion system of polymers undergoing interchange reactions is studied. The equation that describes the dynamics of the system is similar to the Boltzmann equation for a gas of hard spheres. We consider a one-dimensionsl system in which the average length and the concentrations at the boundaries are fixed. The resulting steady states are obtained analytically and with numerical integration of equations obtained by using a local equilibrium approximation. Monte Carlo simulations of experimentally realizable conditions were performed and compared. The results reveal a nonlinear distribution of molecular concentration and mass. The entropy of the polymer distributions is calculated as …

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