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Selected Works

1986

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Articles 1 - 30 of 39

Full-Text Articles in Physical Sciences and Mathematics

Theoretical Studies Of The Reactions Xhn → Xhn-1- + H+ And Xhn-1- + Sih4 → [Sih4xhn-1]-, Mark S. Gordon, Larry P. Davis, Larry W. Burggraf, Robert Damrauer Dec 1986

Theoretical Studies Of The Reactions Xhn → Xhn-1- + H+ And Xhn-1- + Sih4 → [Sih4xhn-1]-, Mark S. Gordon, Larry P. Davis, Larry W. Burggraf, Robert Damrauer

Mark S. Gordon

Ab initio and MNDO calculations have been carried out to evaluate the gas-phase acidities of closed-shell XHn compounds (X= C, N, 0, F, Si, P, S, Cl) and the affinities of silane for the XHn_1- anions. Fourth-order perturbation theory with extended basis sets reproduces the experimental gas-phase acidities to within 2 kcaljmol. Stable pentacoordinated silicon anions are found for X = H, C, N, 0, and F. In contrast, only marginally stable charge-dipole complexes are found for X = Si, S, and Cl.

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On The Glass Transition And Viscosity Of Phosphorus Pentoxide, C. A. Angell, Steve W. Martin Dec 1986

On The Glass Transition And Viscosity Of Phosphorus Pentoxide, C. A. Angell, Steve W. Martin

Steve W. Martin

The calorimetric glass transition temperature Tg for pure anhydrous P2Os melted in sealed Si02 ampules at 1000 “C has been obtained directly for the first time with differential scanning calorimetry, and the increase in heat capacity at Tg has been determined. Tg measured in this way is 57 K higher than the value quoted in the literature, which is probably based on an Arrhenius law extrapolation of viscosity data to 9 = lOI3 P. Combining the high-temperature viscosity data with the common observation that, for oxide glasses, 7 = 10l2 P at the DSC Tg, we find that the P,O, …

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Auroral E-Region Plasma Waves Andelevated Electron Temperatures, Bela G. Fejer, J. Providakes, D. T. Farley, W. E. Swartz Dec 1986

Auroral E-Region Plasma Waves Andelevated Electron Temperatures, Bela G. Fejer, J. Providakes, D. T. Farley, W. E. Swartz

Bela G. Fejer

We have observed 3-m auroral E region plasma waves with a high-resolution 50-MHz radar interferometer at Ithaca. During postmidnight periods of very strong magnetic activity at Ottawa (L = 3.5), the backscattered power and Doppler spectra vary rapidly with time and range and may have both mean Doppler shifts and half power widths in excess of 200 Hz (600 m/s). In addition, when the radar and magnetometer data imply that the current is approximately parallel to the radar line of sight, sharp spectral peaks corresponding to phase velocities approaching 1 km/s sometimes appear suddenly. These persist for at most several …

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Iupac 7th International Symposium On Cationic Polymerization And Related Processes, Otto Vogl, Dietmar Lohmann Dec 1986

Iupac 7th International Symposium On Cationic Polymerization And Related Processes, Otto Vogl, Dietmar Lohmann

Otto Vogl

No abstract provided.

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Centers Of Polymer Chemistry In Czechoslovakia 1: Institute Of Macromolecular Chemistry, Prague, Czechoslovakia, Otto Vogl, Vladimir Kubanek, Jan Sebenda Dec 1986

Centers Of Polymer Chemistry In Czechoslovakia 1: Institute Of Macromolecular Chemistry, Prague, Czechoslovakia, Otto Vogl, Vladimir Kubanek, Jan Sebenda

Otto Vogl

No abstract provided.

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Polymer Science And Engineering In Universities Of The People's Republic Of China: South Of The Yangtze River - Part Ii, Otto Vogl, T. Y. Yu, S. L. Yang Nov 1986

Polymer Science And Engineering In Universities Of The People's Republic Of China: South Of The Yangtze River - Part Ii, Otto Vogl, T. Y. Yu, S. L. Yang

Otto Vogl

No abstract provided.

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Second U.S.-Sweden Workshop On Photochemistry Of Polymers, Otto Vogl, Ann Christine Albertsson, Bengt Ranby Nov 1986

Second U.S.-Sweden Workshop On Photochemistry Of Polymers, Otto Vogl, Ann Christine Albertsson, Bengt Ranby

Otto Vogl

No abstract provided.

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Polymer Science At Universities Of The German Democratic Republic, Otto Vogl, Margit T. Raetzsch, Werner Berger, Guenther Heublein, Joachim Ulbricht Oct 1986

Polymer Science At Universities Of The German Democratic Republic, Otto Vogl, Margit T. Raetzsch, Werner Berger, Guenther Heublein, Joachim Ulbricht

Otto Vogl

No abstract provided.

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Vth International Congress Aplichem "85 International Chemistry Fair, Incheba, 1985, In Bratislava, Otto Vogl, Michal Ilavski, Eberhard Borsig Oct 1986

Vth International Congress Aplichem "85 International Chemistry Fair, Incheba, 1985, In Bratislava, Otto Vogl, Michal Ilavski, Eberhard Borsig

Otto Vogl

No abstract provided.

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Scaling All Correlation Energy In Perturbation Theory Calculations Of Bond Energies And Barrier Heights, Mark S. Gordon, Donald G. Truhlar Sep 1986

Scaling All Correlation Energy In Perturbation Theory Calculations Of Bond Energies And Barrier Heights, Mark S. Gordon, Donald G. Truhlar

Mark S. Gordon

We present and test a new method for scaling all correlation energy as estimated by M0ller-Plesset many-body perturbation theory with popular basis sets. Scale factors that may be useful for future applications are estimated from known bond dissociation energies. We also use scale factors to estimate the barrier heights for two hydrogen-transfer reactions, CH3 + H2 = CH4 + H and OH + CH4 = H20 + CH3•

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Makromolekulares Kolloquium Freiburg, Otto Vogl, Hans-Joachim Cantow Sep 1986

Makromolekulares Kolloquium Freiburg, Otto Vogl, Hans-Joachim Cantow

Otto Vogl

No abstract provided.

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Iupac Polymer Chemistry Meeting, Leuven, Belgium, Otto Vogl, Marcel Van Beylen, Frans C. Deschryver Aug 1986

Iupac Polymer Chemistry Meeting, Leuven, Belgium, Otto Vogl, Marcel Van Beylen, Frans C. Deschryver

Otto Vogl

No abstract provided.

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Japan-U.S. Polymer Symposium, Kyoto, Japan 1985, Jane C. Vogl, T. Takahiko Jul 1986

Japan-U.S. Polymer Symposium, Kyoto, Japan 1985, Jane C. Vogl, T. Takahiko

Otto Vogl

No abstract provided.

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Rigid Backbone: A New Geometry For Percolation, Anthony Roy Day, R. R. Tremblay, A.-M. S. Tremblay Jun 1986

Rigid Backbone: A New Geometry For Percolation, Anthony Roy Day, R. R. Tremblay, A.-M. S. Tremblay

Anthony Roy Day

It is shown that the diluted two-dimensional central-force problem belongs to a new class of percolation problems. Geometric properties such as the fractal dimension of the backbone, the correlation-length exponent, and the connectivity are completely different from those of previously studied percolation problems. Explicit calculations of the backbone and the construction of an algorithm which identifies the infinite rigid cluster clearly demonstrate the absence of singly connected bonds, the overwhelming importance of loops, and the long-range nature of the rigidity.

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Cooling By Immersion In Liquid Nitrogen, Thomas W. Listerman, Thomas A. Boshinski, Lynn F. Knese Jun 1986

Cooling By Immersion In Liquid Nitrogen, Thomas W. Listerman, Thomas A. Boshinski, Lynn F. Knese

Thomas Listerman

When an object is cooled by immersion in a liquid, there is an unexpected increase in the violence of boiling just before the boiling stops. Most people seem fascinated by this phenomenon yet few are acquainted with its explanation in terms of a change in the heat‐transfer mechanism from film boiling to nucleate boiling. We have developed two variations of an intermediate level undergraduate laboratory experiment to measure the heat‐transfer rate after a sample is immersed in liquid nitrogen. The temperature of the sample, as measured by a thermocouple, is recorded as a function of time using either a potentiometer …

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Ferromagnetism Versus Antiferromagnetism In Face-Centered-Cubic Iron, F. J. Pinski, J. Staunton, B. L. Gyorffy, Duane D. Johnson, G. M. Stocks May 1986

Ferromagnetism Versus Antiferromagnetism In Face-Centered-Cubic Iron, F. J. Pinski, J. Staunton, B. L. Gyorffy, Duane D. Johnson, G. M. Stocks

Duane D. Johnson

Using a first-principles disordered-local-moment picture of itinerant-electron magnetism, we calculated the temperature and volume dependence of the magnetic moment and spin-spin correlations for fcc Fe in the paramagnetic state.

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Density-Functional Theory For Random Alloys: Total Energy Within The Coherent-Potential Approximation, Duane D. Johnson, D. M. Nicholson, F. J. Pinski, B. L. Gyorffy, G. M. Stocks May 1986

Density-Functional Theory For Random Alloys: Total Energy Within The Coherent-Potential Approximation, Duane D. Johnson, D. M. Nicholson, F. J. Pinski, B. L. Gyorffy, G. M. Stocks

Duane D. Johnson

A density-functional-based theory is developed for calculation of the total energy and pressure of random substitutional alloys within the Korringa-Kohn-Rostoker coherent-potential approximation. The theory is used to calculate the concentration variation of the equilibrium lattice spacing of α-phase CucZn1−c alloys. We find, in agreement with experiment, that the variation is almost linear and that it deviates from Vegard's rule.

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The Condorequatorial Spread-F Campaign: Overview And Results Of The Large-Scale Measurements, M. C. Kelley, J. Labelle, E. Kudeki, Bela G. Fejer, S. Basu, Su. Basu, K. D. Baker, C. Hanuise, P. Argo, R. F. Woodland, W. E. Swartz, D. T. Farley, J. W. Meriwether May 1986

The Condorequatorial Spread-F Campaign: Overview And Results Of The Large-Scale Measurements, M. C. Kelley, J. Labelle, E. Kudeki, Bela G. Fejer, S. Basu, Su. Basu, K. D. Baker, C. Hanuise, P. Argo, R. F. Woodland, W. E. Swartz, D. T. Farley, J. W. Meriwether

Bela G. Fejer

During the Condor campaign a number of instruments were set up in Peru to support the rocket experiments. In this series of papers we report on the results of the experiments designed to study the equatorial F region. In this overview paper we summarize the main results as well as report upon the macroscopic developments of spread F as evidenced by data from backscatter radars, from scintillation observations, and from digital ionosonde meaurements. In this latter regard, we argue here that at least two factors other than the classical gravitational Rayleigh-Taylor plasma instability process must operate to yield the longest-scale …

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Gigahertz Scintillations And Spaced Receiver Drift Measurements During Project Condorequatorial F-Region Rocket Campaign In Peru, S. Basu, Sa. Basu, J. Labelle, E. Kudeki, Bela G. Fejer, M. C. Kelley, H. E. Whitney May 1986

Gigahertz Scintillations And Spaced Receiver Drift Measurements During Project Condorequatorial F-Region Rocket Campaign In Peru, S. Basu, Sa. Basu, J. Labelle, E. Kudeki, Bela G. Fejer, M. C. Kelley, H. E. Whitney

Bela G. Fejer

Radar backscatter at 50 MHz, rocket, and VHF/GHz scintillation measurements of spread F irregularities at the magnetic equator in Peru were made during the Project Condor campaign in March 1983. The paper discusses the coordinated set of observations on two evenings, March 1 and March 14, 1983, when the altitude of the F region peak differed by more than 150 km. The full complement of equatorial spread F phenomena, namely, the occurrence of 3-m plume structures and VHF/GHz scintillations, were recorded on both these evenings. It was found that the radar backscatter with extended plumes occurs in association with maximum …

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Potential Primary Pyrolysis Processes For Disilane, Mark S. Gordon, Thanh N. Truong, Elizabeth K. Bonderson Apr 1986

Potential Primary Pyrolysis Processes For Disilane, Mark S. Gordon, Thanh N. Truong, Elizabeth K. Bonderson

Mark S. Gordon

Four competing unimolecular decomposition pathways for disilane are considered with use of MP4 energies obtained with an extended basis set and geometries obtained at the MP2/6-31G** computational level. The 1,1- and 1,2-eliminations of H2 and the elimination of silylene to form silane all have similar endothermicities, but the very high activation energy for the I ,2-elimination eliminates this process as a significant contributor at low energies. If disilene is formed in the thermal decomposition of disilane, the more likely source is its higher energy isomer silylsilylene via a relatively low energy I ,2-hydrogen shift.

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Thermal Decomposition Of Silane, Mark S. Gordon, David R. Gano, J. Stephen Binkley, Michael J. Frisch Apr 1986

Thermal Decomposition Of Silane, Mark S. Gordon, David R. Gano, J. Stephen Binkley, Michael J. Frisch

Mark S. Gordon

The essential features of the potential energy surface for the thermal decomposition of silane have been calculated with extended basis sets, augmented by correlation corrections. It is predicted that the transition state for the molecular elimination lies 56.9 kcaljmol above silane. For the reverse reaction, the transition state is less than 2 kcal/mol above the separated fragments, silylene and molecular hydrogen, but 4.8 kcal/mol above a long-range potential well. In the latter, the silylene-H2 separation is 1.78 A, and the bond in H2 has stretched by more than 0.05 A. This indicates a significant electronic interaction between the fragments even …

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Theoretical Studies Of Reactions Of Silanimine (H2sinh) And Its Isomer Aminosilylene (Hsinh2), Thanh N. Truong, Mark S. Gordon Apr 1986

Theoretical Studies Of Reactions Of Silanimine (H2sinh) And Its Isomer Aminosilylene (Hsinh2), Thanh N. Truong, Mark S. Gordon

Mark S. Gordon

The structure and reactivity of unsaturated singlet silicon-nitrogen compounds is theoretically investigated. Ab initio calculations demonstrate that the planar silylene HSiNH2 is the global minimum on the SiNH3 surface, with the planar doubly bound species H2SiNH 18 kcaljmol higher in energy. The internal rotational barriers are computed to be 26.9 kcaljmol for HSiNH2 and 37.9 kcaljmol for H2SiNH. However, the barrier for the inversion of H2SiNH is only 5.6 kcaljmol, so that inversion is favored over rotation for this species. The isomerization connecting H2SiNH to HSiNH2 has a barrier of 60 kcaljmol. The transition-state structures, as well as the exothermicities …

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Predatory Prokaryotes: Predation And Primary Consumption Evolved In Bacteria, Lynn Margulis, Ricardo Guerrero, Carlos Pedrós-Alió, Isabel Esteve, Jordi Mas, David Chase Apr 1986

Predatory Prokaryotes: Predation And Primary Consumption Evolved In Bacteria, Lynn Margulis, Ricardo Guerrero, Carlos Pedrós-Alió, Isabel Esteve, Jordi Mas, David Chase

Lynn Margulis (1938 - 2011)

Two kinds of predatory bacteria have been observed and characterized by light and electron microscopy in samples from freshwater sulfurous lakes in northeastern Spain. The first bacterium, named Vampirococcus, is Gram-negative and ovoidal (0.6 μm wide). An anaerobic epibiont, it adheres to the surface of phototrophic bacteria (Chromatium spp.) by specific attachment structures and, as it grows and divides by fission, destroys its prey. An important in situ predatory role can be inferred for Vampirococcus from direct counts in natural samples. The second bacterium, named Daptobacter, is a Gram-negative, facultatively anaerobic straight rod (0.5 × 1.5 μm) with a single …

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Northern Hemisphere Surface Air Temperature Variations: 1851-1984, P. D. Jones, S. C. B.Raper, Raymond S. Bradley, H. F. Diaz, P. M. Kelly, T. M. L.Wigley Feb 1986

Northern Hemisphere Surface Air Temperature Variations: 1851-1984, P. D. Jones, S. C. B.Raper, Raymond S. Bradley, H. F. Diaz, P. M. Kelly, T. M. L.Wigley

Raymond S Bradley

A new compilation of monthly mean surface air temperature for the Northern Hemisphere for 1851-1984 is presented based on land-based meteorological station data and fixed-position weather ship data. This compilation differs from others in two ways. First, a considerable amount of new data, previously hidden away in archives, has been included, thus improving both spatial and temporal coverage. Second, the station data have been analyzed to assess their homogeneity. Only reliable or corrected station data have been used in calculating area averages. Grid point temperature estimates have been made by interpolating onto a 50 latitude by 100 longitude grid for …

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On The Quadratic Form N12 +N22 +N32 - N42 In Z4, Andrei Ludu Jan 1986

On The Quadratic Form N12 +N22 +N32 - N42 In Z4, Andrei Ludu

Andrei Ludu

No abstract provided.

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Linear Perturbations Of A Constant Coefficient Differential Equation Subject To Mild Integral Smallness Conditions, William Trench Jan 1986

Linear Perturbations Of A Constant Coefficient Differential Equation Subject To Mild Integral Smallness Conditions, William Trench

William F. Trench

No abstract provided.

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Measurements Of Electron Energy Distribution In An Argon Positive Column, Chin Oi Hoong Jan 1986

Measurements Of Electron Energy Distribution In An Argon Positive Column, Chin Oi Hoong

Chin Oi Hoong

The argon positive column plasma of a cold cathode glow discharge is studied using a pulsed single Langmuir Probe technique. It is observed thatthe energy distribution of the electrons in the posotive column is non-maxwellian at a gas pressure of 0.5 mbar. An increase in the gas pressure seems to make the distribution more Maxwellian.

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Pennsylvania's Implementation Of The Surface Mining Control And Reclamation Act: An Assessment Of How "Cooperative Federalism" Can Make State Regulatory Programs More Effective, John C. Dernbach Jan 1986

Pennsylvania's Implementation Of The Surface Mining Control And Reclamation Act: An Assessment Of How "Cooperative Federalism" Can Make State Regulatory Programs More Effective, John C. Dernbach

John C. Dernbach

No abstract provided.

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Sem Views Of Oak Wood, Douglas D. Stokke Jan 1986

Sem Views Of Oak Wood, Douglas D. Stokke

Douglas D. Stokke

The anatomical structure of the secondary xylem (wood) of trees varies with location in the tree. The size, shape, and distribution of cell types varies not only between locations (i.e., stem vs. branch vs. root), but also within an annual ring or across annual rings at a given cross-sectional plane.

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Thermoluminescence (Tl) Dating In Seismic Hazard Evaluations: An Example From The Bonneville Basin, Utah, James P. Mccalpin Jan 1986

Thermoluminescence (Tl) Dating In Seismic Hazard Evaluations: An Example From The Bonneville Basin, Utah, James P. Mccalpin

James P. McCalpin

Thermoluminescence (TL) of minerals is the release of light when grains are heated to 1500 -5000 C. As sediments are buried longer they progressively acquire more TL from accumulated radiation damage from alpha, beta, and gamma rays and cosmic radiation. If the total amount of radiation dose received can be calculated, and the current dose rate measured, then dividing the total dose by the yearly dose rate will yield a TL age. Total doses are calculated by heating the sample until all TL is released, then re-irradiating the sample in the lab with known doses until the natural TL is …

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