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1995

Faculty Publications

Articles 1 - 30 of 39

Full-Text Articles in Physical Sciences and Mathematics

Multifragmentation In E/A=35 Mev Collisions: Evidence For A Coulomb Driven Breakup?, M. D'Agostino, G. J. Kunde, P. M. Milazzo, J. D. Diniu, M. Bruno, N. Colonna, M. L. Fiandri, C. K. Gelbke, T. Glasmacher, F. Gramegna, D. O. Handzy, W. C. Hsi, M. Huang, M. A. Lisa, W. G. Lynch, P. F. Mastinu, C. P. Montoya, A. Moroni, Graham F. Peaslee, L. Phair, R. Rui, C. Schwarz, M. B. Tsang, G. Vannini, C. Williams Dec 1995

Multifragmentation In E/A=35 Mev Collisions: Evidence For A Coulomb Driven Breakup?, M. D'Agostino, G. J. Kunde, P. M. Milazzo, J. D. Diniu, M. Bruno, N. Colonna, M. L. Fiandri, C. K. Gelbke, T. Glasmacher, F. Gramegna, D. O. Handzy, W. C. Hsi, M. Huang, M. A. Lisa, W. G. Lynch, P. F. Mastinu, C. P. Montoya, A. Moroni, Graham F. Peaslee, L. Phair, R. Rui, C. Schwarz, M. B. Tsang, G. Vannini, C. Williams

Faculty Publications

Multifragment disintegrations have been measured for central Au+Au collisions at EA=35 MeV. Fragment emission occurs predominantly at low center of mass energies of about EA≈5 MeV, consistent with a Coulomb dominated breakup of a single source. Mean fragment multiplicities of ⟨NIMF⟩≈10.8 are extracted after correction for the detection efficiency. The fragment charge distributions decrease much more gradually than expected from scaling laws recently applied to the extraction of critical exponents for the nuclear liquid-gas phase transition from nuclear collisions.

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Prompt And Sequential Decay Processes In The Fragmentation Of 40 Mev/A 20ne Projectiles, R. J. Charity, L. G. Sobotka, N. J. Robertson, D. G. Sarantites, J. Dinius, C. K. Gelbke, T. Glasmacher, D. O. Handzy, W. C. Hsi, M. J. Huang, W. G. Lynch, C. P. Montoya, Graham F. Peaslee, C. Schwarz, M. B. Tsang Dec 1995

Prompt And Sequential Decay Processes In The Fragmentation Of 40 Mev/A 20ne Projectiles, R. J. Charity, L. G. Sobotka, N. J. Robertson, D. G. Sarantites, J. Dinius, C. K. Gelbke, T. Glasmacher, D. O. Handzy, W. C. Hsi, M. J. Huang, W. G. Lynch, C. P. Montoya, Graham F. Peaslee, C. Schwarz, M. B. Tsang

Faculty Publications

The fragmentation of E/A=40 MeV Ne20 projectiles into exit channels containing only p, d, t, He3, α, He6, Li6, and Li7fragments has been investigated. Relative shifts between the average longitudinal velocity of each fragment type were measured with Sn120 and Au197 targets. A post-breakup Coulomb acceleration component of these shifts was isolated. Its magnitude indicates that the projectile broke up while in near contact with the target. On the other hand, correlations between projectile fragments indicate that a significant fraction of these fragments are produced by the sequential decay of long- and short-lived unstable intermediates. A fully sequential decay process, …

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Dynamics Of Binary Liquids In Pores, J.C. Lee Dec 1995

Dynamics Of Binary Liquids In Pores, J.C. Lee

Faculty Publications

A computer simulation is performed to study the dynamics of binary liquids in the pores of Vycor glasses. The pores are modeled with glass walls that form randomly interconnected tunnels. When the relaxation is probed with a particular wavelength, the time autocorrelation function depends on whether or not there is a significant periodic or quasiperiodic structure in the distribution of the walls with that wavelength. If there is not, the relaxation may be fitted as the sum of an exponential term and a nonexponential activated term. If there is, the relaxation shows a long-lasting tail that can be fitted by …

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Observation Of Beam-Induced Changes In The Polarization Of Balmer-Α Radiation Emitted Following Beam--Tilted-Foil Transmission, Wang Qi, David D. Allred, Larry V. Knight, Douglas L. Harper, Royal G. Albridge, Norman H. Tolk Dec 1995

Observation Of Beam-Induced Changes In The Polarization Of Balmer-Α Radiation Emitted Following Beam--Tilted-Foil Transmission, Wang Qi, David D. Allred, Larry V. Knight, Douglas L. Harper, Royal G. Albridge, Norman H. Tolk

Faculty Publications

Measurements of the circular polarization of Balmer-α radiation emitted by excited hydrogen atoms, following the transmission of (20-50)-keV protons through thin, tilted amorphous carbon foils, exhibit markedly unexpected behavior as a function of exposure of the foil to the proton beam. Specifically, the circular polarization changes from an initially well understood tilt-angle dependence to a behavior which, for low tilt angles, gives the opposite handedness of circular polarization from that predicted. In addition, the degree of alignment, indicated by the linear Stokes parameter M/I, is enhanced also as a function of dose. These changes in the tilt-angle dependence of the …

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Coincidence Correlations Between Light Charged Particles In The Matched Reactions 905 And 1030 Mev121sb + 27al And 550 And 750 Mev 86kr + 63cu, Winifred E. Parker, Morton Kaplan, David J. Moses, John M. Alexander, Roy B. Lacey, Dalva M. De Castro Rizzo, J. Bolger, A. Narayanan, Graham F. Peaslee, D. G. Popescu Nov 1995

Coincidence Correlations Between Light Charged Particles In The Matched Reactions 905 And 1030 Mev121sb + 27al And 550 And 750 Mev 86kr + 63cu, Winifred E. Parker, Morton Kaplan, David J. Moses, John M. Alexander, Roy B. Lacey, Dalva M. De Castro Rizzo, J. Bolger, A. Narayanan, Graham F. Peaslee, D. G. Popescu

Faculty Publications

Coincidence measurements have been made between and a second particle () produced in the reactions 905 and 1030 MeV and 550 and 750 MeV . All four of the reactions lead to composite systems of 149Tb∗ or 148Gd∗ which facilitates comparisons of matched reactions. In the two reactions and the 550 MeV reaction, the particle-particle coincidences are dominated by processes that lead to evaporation residues. In the 750 MeV reaction, about half of the 1H and 4He are associated with evaporation residue production. These particle-particle coincidences arise from cross sections that are subsets of the total evaporation residue cross sections. …

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Evidence For The Reducibility Of Multifragment Emission To An Elementary Binary Emission In Xe-Induced Reactions, K. Tso, L. Phair, A. Colonna, W. Skulski, G. J. Wozniak, L. G. Moretto, D. R. Bowman, M. Chartiet, C. K. Gelbke, W. G. Gong, W. C. Hsi, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, C. Schwarz, R. T. De Souza, M. B. Tsang, F. Zhu Nov 1995

Evidence For The Reducibility Of Multifragment Emission To An Elementary Binary Emission In Xe-Induced Reactions, K. Tso, L. Phair, A. Colonna, W. Skulski, G. J. Wozniak, L. G. Moretto, D. R. Bowman, M. Chartiet, C. K. Gelbke, W. G. Gong, W. C. Hsi, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, C. Schwarz, R. T. De Souza, M. B. Tsang, F. Zhu

Faculty Publications

Multifragmentation for 129Xe-induced reactions on several targets (natCu, 89Y, 165Ho, 197Au) has been studied at . The probability of emitting n intermediate mass fragments is shown to be binomial at each transversal energy and reducible to an elementary binary probability p. For each target and at each bombarding energy, p shows a thermal behavior as demonstrated by linear Arrhenius plots. A nearly universal linear Arrhenius plot is observed at each bombarding energy, independent of target. The sensitivity of p to the Zthreshold points to its physical significance and rules out auto-correlation effects.

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Understanding Proton Emission In Central Heavy-Ion Collisions, D. O. Handzy, W. Bauer, F. C. Daffin, S. J. Gaff, C. K. Gelbke, T. Glasmacher, E. Gualtieri, S. Hannuschke, M. J. Huang, G. J. Kunde, R. Lacey, T. Li, M. A. Lisa, W. J. Llope, W. G. Lynch, L. Martin, C. P. Montoya, R. Pak, Graham F. Peaslee, S. Pratt, C. Schwarz, N. Stone, M. B. Tsang, A. M. Vander Molen, G. D. Westfall, J. Yee, S. J. Yennello Oct 1995

Understanding Proton Emission In Central Heavy-Ion Collisions, D. O. Handzy, W. Bauer, F. C. Daffin, S. J. Gaff, C. K. Gelbke, T. Glasmacher, E. Gualtieri, S. Hannuschke, M. J. Huang, G. J. Kunde, R. Lacey, T. Li, M. A. Lisa, W. J. Llope, W. G. Lynch, L. Martin, C. P. Montoya, R. Pak, Graham F. Peaslee, S. Pratt, C. Schwarz, N. Stone, M. B. Tsang, A. M. Vander Molen, G. D. Westfall, J. Yee, S. J. Yennello

Faculty Publications

Two-proton correlation functions for central collisions of 36Ar+45Sc at E/A=80, 120, and 160 MeV are compared to calculations with the Boltzmann-Uehling-Uhlenbeck (BUU) transport model. Agreement is found at E/A=80MeV, but the model predicts too large correlations at E/A=120 and 160 MeV. The discrepancy may be due to delayed emission of protons from particle-unstable states not modeled in BUU.

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Structure Factors Of Binary Fluids In A Dilute Gel, J.C. Lee Oct 1995

Structure Factors Of Binary Fluids In A Dilute Gel, J.C. Lee

Faculty Publications

The statio and dynamic structure factors of binary fluids in a dilute gel are computed using a two-dimensional kinetic Ising model. The wetting effect of the gel strands is modeled with ''gel atoms'' which are distributed randomly among the spins and impose a field on their neighboring spins, all in the same direction. The result for the static structure factor shows the presence of adsorption clusters which mask the gel atoms. The result for the dynamic Structure factor shows an extremely slow relaxation-at late times which cannot be fitted in the form of the activated dynamic scaling known for random-field …

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A Provably Convergent Dynamic Training Method For Multi-Layer Perceptron Networks, Timothy L. Andersen, Tony R. Martinez Sep 1995

A Provably Convergent Dynamic Training Method For Multi-Layer Perceptron Networks, Timothy L. Andersen, Tony R. Martinez

Faculty Publications

This paper presents a new method for training multi-layer perceptron networks called DMP1 (Dynamic Multilayer Perceptron 1). The method is based upon a divide and conquer approach which builds networks in the form of binary trees, dynamically allocating nodes and layers as needed. The individual nodes of the network are trained using a genetic algorithm. The method is capable of handling real-valued inputs and a proof is given concerning its convergence properties of the basic model. Simulation results show that DMP1 performs favorably in comparison with other learning algorithms.

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Assessing The Evolutionary Nature Of Multifragment Decay, E. Cornell, T. M. Hamilton, 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, W. A. Friedman Aug 1995

Assessing The Evolutionary Nature Of Multifragment Decay, E. Cornell, T. M. Hamilton, 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, W. A. Friedman

Faculty Publications

Multifragment decays of central collisions in 84Kr+197Au at E/A=35, 55, and 70 MeV are studied. The dependence of the extracted emission time on the velocity of the fragment pair is investigated. More energetic pairs manifest a stronger Coulomb interaction, indicating emission from a source of smaller spatial-temporal extent than less energetic pairs. This trend can be understood in the context of a statistical model that allows the source characteristics to evolve as the fragments are emitted.

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Ultrastructural Immunolocalization Of Histones (H2b, H3, H4), Transition Protein (Tp1) And Protamine In Rabbit Spermatids And Spermatozoa Nuclei. Relation To Condensation Of The Chromatin, J L. Courtens, Wilson Stephen Kistler, L Plöen Aug 1995

Ultrastructural Immunolocalization Of Histones (H2b, H3, H4), Transition Protein (Tp1) And Protamine In Rabbit Spermatids And Spermatozoa Nuclei. Relation To Condensation Of The Chromatin, J L. Courtens, Wilson Stephen Kistler, L Plöen

Faculty Publications

The histones H2B, H3 and H4, the transition protein TP1 and protamine were localised using ultrastructural immunocytochemistry in nuclei of rabbit spermatids and spermatozoa. Histones are present in round spermatid nuclei and are lost during the elongation of nuclei. TP1 and protamine appear simultaneously in all nuclei during this period. TP1 is located at the periphery of chromatin cords, while protamine seems to be located at random in the same cords. TP1 is lost in most elongated sprematids during step 13 of spermiogenesis, and the protamine stays in all sperm nuclei. TP1 remains persent in some old spermatids and ejaculated …

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Space-Time Characteristics Of Fragment Emission In The E/A=30 Mev 129xe + Natcu Reaction, D. R. Bowman, N. Colonna, W. A. Friedman, L. Celano, M. D'Agostino, J. D. Dinius, A. Ferrero, C. K. Gelbke, T. Glasmacher, D. O. Handzy, D. Horn, W. C. Hsi, M. Huang, I. Iori, M. A. Lisa, W. G. Lynch, G. V. Margagliotti, P. M. Milazzo, C. P. Montoya, A. Moroni, Graham F. Peaslee, L. Phair, F. Petruzzelli, R. Scardaoni, C. Schwarz, M. B. Tsang, C. Williams Aug 1995

Space-Time Characteristics Of Fragment Emission In The E/A=30 Mev 129xe + Natcu Reaction, D. R. Bowman, N. Colonna, W. A. Friedman, L. Celano, M. D'Agostino, J. D. Dinius, A. Ferrero, C. K. Gelbke, T. Glasmacher, D. O. Handzy, D. Horn, W. C. Hsi, M. Huang, I. Iori, M. A. Lisa, W. G. Lynch, G. V. Margagliotti, P. M. Milazzo, C. P. Montoya, A. Moroni, Graham F. Peaslee, L. Phair, F. Petruzzelli, R. Scardaoni, C. Schwarz, M. B. Tsang, C. Williams

Faculty Publications

Intermediate-mass-fragment emission has been studied in central E/A=30 MeV Xe129+natCu reactions. The measured fragment multiplicities, reduced-velocity correlation functions, and emission velocities have been compared with schematic three-body trajectory calculations and with three statistical models with input based upon a dynamical BNV code. The statistical models which include expansion either explicitly or implicitly are able to generate a sufficient number of fragments. The three-body trajectory calculations indicate a mean emission time of ≊200 fm/c, consistent with sequential decay. Dynamical expanding-emitting source calculations predict a similar time scale for fragment emission and give satisfactory agreement with the experimental correlation functions if the …

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An Integrated Framework For Learning And Reasoning, Christophe G. Giraud-Carrier, Tony R. Martinez Aug 1995

An Integrated Framework For Learning And Reasoning, Christophe G. Giraud-Carrier, Tony R. Martinez

Faculty Publications

Learning and reasoning are both aspects of what is considered to be intelligence. Their studies within AI have been separated historically, learning being the topic of machine learning and neural networks, and reasoning falling under classical (or symbolic) AI. However, learning and reasoning are in many ways interdependent. This paper discusses the nature of some of these interdependencies and proposes a general framework called FLARE, that combines inductive learning using prior knowledge together with reasoning in a propositional setting. Several examples that test the framework are presented, including classical induction, many important reasoning protocols and two simple expert systems.

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Surface Intersection Loop Destruction, Thomas W. Sederberg, Alan K. Zundel Jul 1995

Surface Intersection Loop Destruction, Thomas W. Sederberg, Alan K. Zundel

Faculty Publications

The intersection curve between two surface patches consists of one or more connected components or branches. Each component can be classified as either an open branch, with endpoints on at least one patch boundary, or as a closed loop.

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Reducibility And Thermal Scaling Of Charge Distributions In Multifragmentation, L. Phair, K. Tso, R. Ghetti, G. J. Wozniak, L. G. Moretto, R. T. De Souza, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu Jul 1995

Reducibility And Thermal Scaling Of Charge Distributions In Multifragmentation, L. Phair, K. Tso, R. Ghetti, G. J. Wozniak, L. G. Moretto, R. T. De Souza, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu

Faculty Publications

A strong thermal signature is found in the charge distributions associated with multifragmentation from the reaction 36Ar+197Au at E/A=110 MeV. The n-fold charge distributions are reducible to the onefold charge distributions through a simple scaling that is dictated by fold number and charge conservation.

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Numerical Calculation Of Axisymmetric Electrostatic Modes For Cold Finite-Length Non-Neutral Plasmas, Johnny K. Jennings, Ross L. Spencer, K. C. Hansen Jul 1995

Numerical Calculation Of Axisymmetric Electrostatic Modes For Cold Finite-Length Non-Neutral Plasmas, Johnny K. Jennings, Ross L. Spencer, K. C. Hansen

Faculty Publications

A numerical calculation of mode frequencies for cold, non-neutral plasmas is reported. The numerical method can be applied to any axisymmetric plasma shape in a trap. Here, it is used to study axisymmetric electrostatic modes in a long conducting cylinder. These modes were previously studied by Prasad and O'Neil [Phys. Fluids 26, 665 (1983)] and by Dubin [Phys. Rev. Lett. 66, 2076 (1991)]. In contrast to Dubin's calculation, the effects of a nearby cylindrical wall, including its influence on the shape of the plasma equilibrium, are considered. It is found that for plasmas with aspect ratios (length divided by diameter) …

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Computer Simulation Study Of The Permeability Of Driven Polymers Through Porous Media, Grace M. Foo, Ras B. Pandey Jun 1995

Computer Simulation Study Of The Permeability Of Driven Polymers Through Porous Media, Grace M. Foo, Ras B. Pandey

Faculty Publications

A computer simulation model is used to study the permeability of polymer chains driven by a biased flow field through a porous medium in two dimensions. The chains are modeled by constrained self-avoiding walks, which reptate through the heterogeneous medium with a biased probability imposed by the driven field. A linear response description is used to evaluate an effective permeability. The permeability σ shows an unusual decay behavior on reducing the porosity ps. We find that the permeability decreases on increasing the bias above a characteristic value Bc. This characteristic bias shows a logarithmic decay on …

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Space-Time Ambiguity Of Two- And Three-Fragment Reduced Velocity Correlation Functions, T. Glasmacher, L. Phair, D. R. Bowman, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, R. T. De Souza, M. B. Tsang, F. Zhu Jun 1995

Space-Time Ambiguity Of Two- And Three-Fragment Reduced Velocity Correlation Functions, T. Glasmacher, L. Phair, D. R. Bowman, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, R. T. De Souza, M. B. Tsang, F. Zhu

Faculty Publications

Reduced-velocity correlation functions between two and three intermediate mass fragments are compared for central Ar36+197Ar collisions at E/A=50 MeV. Previously published N-body Coulomb-trajectory calculations, capable of reproducing the measured two-fragment reduced velocity-correlation function, describe the measured three-fragment correlation function equally well. Moreover, ambiguities between source size and lifetime observed in the analysis of two-fragment correlations remain unresolved in the three-fragment correlation function.

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On The Equivalence Of Certain Consequences Of The Proper Forcing Axiom, Peter Nyikos, Leszek Piatkiwicz Jun 1995

On The Equivalence Of Certain Consequences Of The Proper Forcing Axiom, Peter Nyikos, Leszek Piatkiwicz

Faculty Publications

No abstract provided.

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Hodographs And Normals Of Rational Curves And Surfaces, Thomas W. Sederberg, Takafumi Saito, Guo-Jin Wang Jun 1995

Hodographs And Normals Of Rational Curves And Surfaces, Thomas W. Sederberg, Takafumi Saito, Guo-Jin Wang

Faculty Publications

Derivatives and normals of rational Bézier curves and surface patches are discussed. A non-uniformly scaled hodograph of a degree m x n tensor-product rational surface, which provides correct derivative direction but not magnitude, can be written as a degree (2m - 2) x 2n or 2m x (2n - 2) vector function in polynomial Bézier form. Likewise, the scaled normal direction is degree (3m - 2) x(3n - 2). Efficient methods are developed for bounding these directions and the derivative magnitude.

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The Effect Of Domain Knowledge On Elementary School Children's Search Behavior On An Information Retrieval System: The Science Library Catalog, Sandra Hirsh May 1995

The Effect Of Domain Knowledge On Elementary School Children's Search Behavior On An Information Retrieval System: The Science Library Catalog, Sandra Hirsh

Faculty Publications

Few information retrieval systems are designed with children’s special needs and capabilities in mind. We need to learn more about children’s information-seeking behavior in order to provide them with information-based tools which support exploratory learning. This dissertation examines children’s search behavior on a hypertext-based automated library catalog designed for elementary school children. The focus of this research is on the effect of domain knowledge on children’s search performance, search behavior, and learning as they look for science books on this system. Reseaxch has shown that level of domain knowledge in~luences the way people search for information. Data was collected through …

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Federal Minimums: Insufficient To Save The Bay, Roy A. Hoagland, Jean G. Watts May 1995

Federal Minimums: Insufficient To Save The Bay, Roy A. Hoagland, Jean G. Watts

Faculty Publications

No abstract provided.

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Accuracy Of Deoxynucleotide Incorporation By Soybean Chloroplast Dna-Polymerases Is Independent Of The Presence Of A 3' To 5' Exonuclease, J. Clinton Bailey Ii, Sabine Heinhorst, Gordon C. Cannon Apr 1995

Accuracy Of Deoxynucleotide Incorporation By Soybean Chloroplast Dna-Polymerases Is Independent Of The Presence Of A 3' To 5' Exonuclease, J. Clinton Bailey Ii, Sabine Heinhorst, Gordon C. Cannon

Faculty Publications

DNA polymerase was purified from soybean (Glycine max) chloroplasts that were actively replicating DNA. The main form (form I) of the enzyme was associated with a low level of 3' to 5' exonuclease activity throughout purification, although the ratio of exonuclease to polymerase activity decreased with each successive purification step. A second form (form II) of DNA polymerase, which elutes from DEAE-cellulose at a higher salt concentration than form I, was devoid of any exonuclease activity. To assess the potential function of the 3' to 5' exonuclease in proofreading, the fidelity of deoxynucleotide incorporation was measured for form I DNA …

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Computer-Simulation Study Of The Permeability Of A Porous Sediment Model, Ras B. Pandey, Jeffrey L. Becklehimer Apr 1995

Computer-Simulation Study Of The Permeability Of A Porous Sediment Model, Ras B. Pandey, Jeffrey L. Becklehimer

Faculty Publications

A computer simulation model is used to study the permeability of fluid flow through porous media generated by the random distribution of the sediments in a two-dimensional lattice. Fluid particles are confined to pore space with the sediments forming the rigid barriers at the pore boundaries. An interaction between the fluid particles and the pore substrate is introduced to incorporate the additional drag in the pore space. The pressure gradient causes a bias to drive the fluid and the Metropolis algorithm is used to hop the fluid particles. The permeability of this system is studied as a function of the …

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A Reverse Isoperimetric Inequality, Stability And Extremal Theorems For Plane-Curves With Bounded Curvature, Ralph Howard, Andrejs Treibergs Apr 1995

A Reverse Isoperimetric Inequality, Stability And Extremal Theorems For Plane-Curves With Bounded Curvature, Ralph Howard, Andrejs Treibergs

Faculty Publications

No abstract provided.

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Are Multifragment Emission Probabilities Reducible To An Elementary Binary Emission Probability, L. G. Moretto, L. Phair, K. Tso, K. Jing, G. J. Wozniak, R. T. Souza, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu Feb 1995

Are Multifragment Emission Probabilities Reducible To An Elementary Binary Emission Probability, L. G. Moretto, L. Phair, K. Tso, K. Jing, G. J. Wozniak, R. T. Souza, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu

Faculty Publications

Experimental intermediate-mass-fragment multiplicity distributions for the EA=80 and 110 MeV Ar36 + Au197reactions are shown to be binomial at all excitation energies. From these distributions, a single binary event probability p can be extracted that has a thermal dependence. Thus, it is inferred that multifragmentation is reducible to a combination of nearly independent emission processes. If sequential decay is assumed, the increase of p with excitation energy implies a contraction of the time scale that is qualitatively consistent with recent fragment-fragment correlation data.

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Multifragmentation And Flow: Peripheral Vs. Central Collisions, J. Pochodzalla, S. Aiello, M. Begemann-Blaich, Th. Blaich, D. R. Bowman, R. J. Charity, A. Cosmo, A. Ferrero, C. K. Gelbke, W. C. Hsi, J. Hubele, G. Imme, I. Iori, J. Kempter, P. Kreutz, G. J. Kunde, W. D. Kunze, V. Lindenstruth, M. A. Lisa, W. G. Lynch, U. Lynen, M. Mang, L. G. Moretto, A. Moroni, W. F.J. Müller, M. Neumann, B. Ocker, C. A. Ogilive, V. Pappalardo, Graham F. Peaslee, G. Raciti, F. Rosenberger, T. Rubehn, H. Sann, R. Scardaoni, A. Schüttauf, W. Seidei, V. Serfling Feb 1995

Multifragmentation And Flow: Peripheral Vs. Central Collisions, J. Pochodzalla, S. Aiello, M. Begemann-Blaich, Th. Blaich, D. R. Bowman, R. J. Charity, A. Cosmo, A. Ferrero, C. K. Gelbke, W. C. Hsi, J. Hubele, G. Imme, I. Iori, J. Kempter, P. Kreutz, G. J. Kunde, W. D. Kunze, V. Lindenstruth, M. A. Lisa, W. G. Lynch, U. Lynen, M. Mang, L. G. Moretto, A. Moroni, W. F.J. Müller, M. Neumann, B. Ocker, C. A. Ogilive, V. Pappalardo, Graham F. Peaslee, G. Raciti, F. Rosenberger, T. Rubehn, H. Sann, R. Scardaoni, A. Schüttauf, W. Seidei, V. Serfling

Faculty Publications

Multifragment decays of heavy nuclei have been studied at the ALADIN spectrometer system at beam energies between 100 and 1000 MeV per nucleon. The observed fragment distributions signal a universality of spectator decays at bombarding energies . The role of the radial flow for the fragmentation process is explored by comparing fragment distributions measured for Au+Au collisions at in central collisions and at in more peripheral reactions. At both energies the maximum multiplicity of intermediate mass fragments (IMFs) normalized to the size of the decaying system is about one IMF per 30 nucleons but the element distributions show significant differences. …

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Multifragment Emission Times In Xe Induced Reactions, A. Moroni, D. R. Bowman, M. Bruno, P. Buttazzo, L. Celano, N. Colonna, M. D'Agostino, J. D. Dinius, A. Ferrero, M. L. Fiandri, K. Gelbke, T. Glasmacher, F. Gramegna, D. O. Handzy, D. Horn, Wen-Chien Hsi, M. Huang, I. Iori, M. Lisa, W. G. Lynch, G. V. Margagliotti, P. F. Mastinu, P. M. Milazzo, C. Montoya, Graham F. Peaslee, L. Phair, F. Petruzzelli, R. Rud, R. Scardaoni, C. Schwarz, B. Tsang, G. Vannini, C. Williams Feb 1995

Multifragment Emission Times In Xe Induced Reactions, A. Moroni, D. R. Bowman, M. Bruno, P. Buttazzo, L. Celano, N. Colonna, M. D'Agostino, J. D. Dinius, A. Ferrero, M. L. Fiandri, K. Gelbke, T. Glasmacher, F. Gramegna, D. O. Handzy, D. Horn, Wen-Chien Hsi, M. Huang, I. Iori, M. Lisa, W. G. Lynch, G. V. Margagliotti, P. F. Mastinu, P. M. Milazzo, C. Montoya, Graham F. Peaslee, L. Phair, F. Petruzzelli, R. Rud, R. Scardaoni, C. Schwarz, B. Tsang, G. Vannini, C. Williams

Faculty Publications

Multifragment emission is studied in reactions. The emission process for central collisions occurs on a time scale of ≈ 200 fm/c at 30 MeV/n. Intermediate-mass-fragment yields, velocity correlation functions and emission velocities of Z=6 fragments are compared with predictions of statistical decay models.

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Dynamics Of Order-Parameter-Conserving Ising Models At T > Tc, J.C. Lee Feb 1995

Dynamics Of Order-Parameter-Conserving Ising Models At T > Tc, J.C. Lee

Faculty Publications

http://journals.aps.org/prb/pdf/10.1103/PhysRevB.51.2661

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Phase Coexistence In Multifragmentation?, L. G. Moretto, L. Phair, R. Ghetti, K. Tso, N. Colonna, W. Skulski, G. J. Wozniak, D. R. Bowman, N. Carlin, M. Chartier, C. K. Gelbke, W. G. Gong, W. C. Hsi, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, C. Schwarz, R. T. De Souza, M. B. Tsang, F. Zhu Jan 1995

Phase Coexistence In Multifragmentation?, L. G. Moretto, L. Phair, R. Ghetti, K. Tso, N. Colonna, W. Skulski, G. J. Wozniak, D. R. Bowman, N. Carlin, M. Chartier, C. K. Gelbke, W. G. Gong, W. C. Hsi, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, C. Schwarz, R. T. De Souza, M. B. Tsang, F. Zhu

Faculty Publications

The charge ( Z) distributions from intermediate energy heavy-ion reactions depend upon the multiplicity n of intermediate mass fragments through a factor of the form e−cnZ. Experimentally c starts from zero at low values of the transverse energy Et and reaches a saturation value at high Et. In a liquid-gas phase diagram c=0 for the saturated vapor, while c>0 for the unsaturated vapor. It is suggested that in the c≈0 regime the source evaporates down to a sizable remnant, while for c>0 the source vaporizes completely. Percolation of finite systems and nuclear evaporation portray a behavior similar to …

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