Physical Sciences and Mathematics Commons^™

Centers Of Polymer Research; Polymer Science In The South And West Of Japan, Otto Vogl, T. Kunitake, J. Kiji

Otto Vogl

No abstract provided.

Symposium On Functional Polymers, Kunming, Yunnan, People’S Republic Of China, Otto Vogl, K. Takemoto

Otto Vogl

No abstract provided.

Centers Of Polymer Research; Polymer Science In The Nagoya Area, Otto Vogl, M. Nagasawa, Y. Yamashita

Otto Vogl

No abstract provided.

U.S.-Swedish Workshop On Photodegradation And Photostabilization Of Polymers, Otto Vogl, Bengt Ranby

Otto Vogl

No abstract provided.

Spin Systems On Hierarchical Lattices. Introduction And Thermodynamic Limit, Robert B. Griffiths, Miron Kaufman

Miron Kaufman

A number of exactly soluble models in statistical mechanics can be produced with the use of spins interacting with nearest neighbors on a hierarchical lattice. A general definition and several examples of such lattices are given, and the topological properties of one of these, the "diamond" lattice, are discussed in detail. It is shown that the free energy has a well-defined thermodynamic limit for a large class of discrete spin models on hierarchical lattices.

First-Order Transitions In Defect Structures At A Second-Order Critical Point, Miron Kaufman, Robert B. Griffiths

Miron Kaufman

On certain hierarchical lattices the order parameter on a defect line increases discontinuously at the bulk critical temperature for q-state Potts models when q is sufficiently large, even though the bulk order parameter increases continuously. It is suggested that the same behavior may occur for two-dimensional lattices with 2 < q <= 4.

Excited States And Photochemistry Of Saturated Molecules. 11. Potential Energy Surfaces In Low-Lying States Of Ethane, James W. Caldwell, Mark S. Gordon

Mark S. Gordon

Ab initio calculations at both the restricted Hartree-Fock (RHF) and singly excited configuration interaction (SEC I) levels have been carried out on sections of the potential energy surfaces for a number of low-lying excited singlet electronic states of ethane. All vertical states below the first ionization potential are predominantly Rydberg in character, as are all minima detected on the potential energy surfaces. The lowest 1Eg state is predicted to have only a very small (""" 1 kcal/mol) barrier separating its minimum-energy structure from the 1A" ethylidene + 1 ~/ H2 products. Since the vertical Eg molecule has more than enough …

Centers Of Polymer Research; Polymer Science In Osaka, Japan: Part Ii, Otto Vogl, T. Otsu, K. Hatada

Otto Vogl

No abstract provided.

Regression Analysis In Health Services Research: The Use Of Dummy Variables, Paula Diehr, Lincoln Nayak Polissar

Paula Diehr

Dummy variables frequently are used in regression analysis but often in an incorrect fashion. A brief review of examples in the medical care literature showed that the interpretation of dummy variable regression coefficients and their significance was often incorrect or unclear. This article shows how dummy variables can be used and assessed properly. The importance of testing for the joint effect of a group of dummy variables is stressed. It also gives a standard and useful extension of the dummy variable technique to testing for the effect of collections of variables.

Gas-Phase Photolysis Of 2,2-Dimethylbutane, 2,2,3-Trimethylbutane, 2,2,3-Trimethyl-2-Silabutane, And 2,2,3,3-Tetramethyl-2-Silabutane At 147 Nm, Daryl J. Doyle, S. K. Tokach, Mark S. Gordon, Robert D. Koob

Mark S. Gordon

The 147-nm photolyses of 2,2-dimethylbutane, 2,2,3-trimethylbutane, 2,2,3-trimethyl-2-silabutane (isopropyltrimethylsilane), and 2,2,3,3-tetramethyl-2-silabutane (tert-butyltrimethylsilane) are reported. In addition, the mercury-sensitized photolyses of i-C4H10, trimethylsilane, and mixtures of i-C4H10 and trimethylsilane are reported which give disproportionation to combination (D/C) ratios of 2.1 ::1::0.2 and 0.28::1::0.05 for (CH3) 3C + (CH3) 3C and (CH3)gSi + (CH3)gSi, respectively, and D/C ratios of 1.86::1:: 0.15 and 0.55 ::1:: 0.08 for (CH3)gC + (CH3)aSi to form 2-methyl-2-silapropene and i-C4H8, respectively. With the completion of this work, several trends and generalizations can be drawn concerning the importance of various processes in linear vs. branched alkanes and alkylsilanes. These conclusions …

Centers Of Polymer Research; Polymer Science In Osaka, Japan: Part I, Otto Vogl, T. Otsu, K. Hatada

Otto Vogl

No abstract provided.

Effects Of Polar Substituents On Carbon-Silicon Multiple Bonds, Mark S. Gordon

Mark S. Gordon

The results of ab initio calculations on the effects of fluorine and lithium substitution on silaethyne and silaethylene and their isomers are presented. It is found that fluorine has a strong stabilizing effect when attached to silicon. This results in the predictions (a) that a distorted 1-fluoro-1-silaethyne is the most stable structure of HCSiF and (b) that 1,1-difluoro- 1-silaethylene is much lower in energy than 1,2-difluoromethylsilylene. Approximate correlation corrections are added to study the HC~iF - FHC=Si and HC==SiLi - LiHC=Si potential energy surfaces.

Centers Of Polymer Research; Polymer Science In Tokyo, Japan, Part Iii: Suburban Area, Otto Vogl, I. Uematsu, A. Abe

Otto Vogl

No abstract provided.

Centers Of Polymer Research; Polymer Science In Tokyo, Japan, Part Ii: Suburban Area, Otto Vogl, I. Uematsu, A. Abe

Otto Vogl

No abstract provided.

Long Wavelength Irregularities In The Equatorial Electrojet, E. Kudeki, D. T. Farley, Bela G. Fejer

Bela G. Fejer

We have used the radar interferometer technique at Jicamarca to study in detail irregularities with wavelengths of a few kilometers generated in the unstable equatorial electrojet plasma during strong type 1 conditions. In-situ rocket observations of the same instability process are discussed in a companion paper. These large scale primary waves travel essentially horizontally and have large amplitudes. The vertical electron drift velocities driven by the horizontal wave electric fields reach or exceed the ion-acoustic velocity even though the horizontal phase velocity of the wave is considerably smaller. A straightforward extension to the long wavelength regime of the usual linear …

In-Situ Measurements Ofwave Electric Fields In The Equatorial Electrojet, R. C. Pfaff, M. C. Kelley, Bela G. Fejer, N. C. Maynard, K. D. Baker

Bela G. Fejer

Electric field wave measurements have been performed on two sounding rockets in the equatorial ionosphere. During a daytime flight from Chilca, Peru, intense electrostatic waves were detected on the upward directed electron density gradient. During a nighttime flight from Kwajalein Atoll, similar waves were detected on a downward directed gradient. These results are in agreement with a gradient drift instability explanation of the generation of the waves. The wave amplitudes were as high as 5 mV/m implying perturbation drifts comparable to the driving drift velocities. Power spectra from the turbulent region show a peak at long wavelengths, followed by a …

Polymer Science In The Peoples Republic Of China, Otto Vogl, K. Takemoto

Otto Vogl

No abstract provided.

Subduction Of The Caribbean Plate And Basement Uplifts In The Overriding South American Plate, James N. Kellogg, William E. Bonini

James N Kellogg

Abstract. The new tectonic interpretations presented in this paper are based on geologic field mapping and gravity data supplemented by well logs, seismic profiles, and radiometric and earthquake data. The present Caribbean-South American plate boundary is the South Caribbean marginal fault, where subduction is indicated by folding and thrusting in the deformed belt and a seismic zone that dips 30o to the southeast and terminates 200 km below the Maracaibo Basin. The Caribbean-South American convergence rate is estimated as 1.9 +_. 0.3 cm/yr on the basis of the 390-km length of the seismic zone and a thermal equilibration time of …

Electro-Optics Applications For Alleviating Emi/Emc/Emp Problems, George H. Baker, Walter H. Hardwick

George H Baker

No abstract provided.

Structure-Factor Measurements In 4he As A Function Of Density, Robert Hallock, H. N. Robkoff

Robert Hallock

Measurements of the structure factor S(k) for 4He are reported as a function of pressure at 1.67, 2.20, and 4.24 K from saturated vapor pressure to 25 atm. The liquid structure factor is seen to sharpen and increase in amplitude with an increase in pressure at each of the temperatures studied. Comparison is made to previous results obtained by the technique of neutron scattering as well as to the theoretical predictions of Chang and Campbell and of Whitlock et al. The pair correlation function g(r) is obtained from the liquid structure factor by means of a Fourier transform, and comparison …

Excited States And Photochemistry Of Saturated Molecules. X. Ab Initio Calculations On The Vertical States Of Methylsilane, Mark S. Gordon

Mark S. Gordon

The vertical excitation energies are investigated for singlet and triplet states of methylsilane. To analyze the importance of Rydberg functions and of both valence and Rydbergd functions, a sequence of ten different basis sets are considered in conjuction with a single excitation configuration interaction. It is found that all of the singlet states below the first ionization potential may be characterized as Rydberg states, while there is considerable valence character in some of the low‐lying triplets. If the valence s and p functions are represented reasonably well (e.g., with a split valence basis set), the role of valence d orbitals …

Self‐Consistent Molecular Orbital Methods. Xxiii. A Polarization‐Type Basis Set For Second‐Row Elements, Michelle M. Franci, William J. Pietro, Warren J. Hehre, J. Stephen Binkley, Mark S. Gordon, Douglas J. Defrees, John A. Pople

Mark S. Gordon

The 6‐31G* and 6‐31G** basis sets previously introduced for first‐row atoms have been extended through the second‐row of the periodic table. Equilibrium geometries for one‐heavy‐atom hydrides calculated for the two‐basis sets and using Hartree–Fock wave functions are in good agreement both with each other and with the experimental data. HF/6‐31G* structures, obtained for two‐heavy‐atom hydrides and for a variety of hypervalent second‐row molecules, are also in excellent accord with experimental equilibrium geometries. No large deviations between calculated and experimental single bond lengths have been noted, in contrast to previous work on analogous first‐row compounds, where limiting Hartree–Fock distances were in …

Thermodynamic Model For Tricritical Mixtures With Application To Ammonium, Miron Kaufman, Robert B. Griffiths

Miron Kaufman

Procedures are developed for using composition data in the three-phase region and variations of meniscus heights to determine the parameters needed to relate a classical thermodynamic model for fluid mixtures near tricritical points to actual experiments. In the case of the mixture ammonium sulfate + water + ethanol + benzene the result is a reasonably good fit to a variety of data, including light scattering measurements of intensity and correlation length. There is some evidence for deviations from the classical theory, but it is not unambiguous.

Infinite Susceptibility At High Temperatures In The Migdal-Kadanoff Scheme, Miron Kaufman, Robert B. Griffiths

Miron Kaufman

The Migdal-Kadanoff real-space renormalisation group scheme applied to the Ising and classical XY (and probably other) ferromagnetic models yields an infinite susceptibility at all temperatures above the critical temperature for a hypercubic lattice of dimension d > 2.

Measurement Of Synchrotron X-Ray Energies And Line Shapes Using Diffraction Markers, Juana Vivó Acrivos, S.S. P. Parkin, K. Hathaway, J. R. Reynolds, M. P. Klein, A. Thompson, D. Goodin

Juana Vivó Acrivos

Standard reference markers for accurate, reproducible synchrotron x-ray energies are obtained using a three Si crystal spectrometer. The first two crystals are in the monochromator and the third is used to obtain diffraction markers which monitor the energy. Then for any value of the glancing angle on the reference Si crystal the energy for the (333) diffraction must occur at 3/4 that of the (444) and 3/5 of that for the (555). This establishes for the first time an absolute synchrotron energy scale. Higher-order diffractions are used to determine excitation line profiles. We conclude that the use of reference diffractions …

Structural Properties Of Ideals, J. Baumgartner, A. Taylor, Stan Wagon

Stan Wagon, Retired

No abstract provided.

Y Expansion For Directed Lattice Animals, Anthony Day, T. Lubensky

Anthony Roy Day

No abstract provided.

Path-Integrals And The Wkb Approximation, Br Holstein, Ar Swift

Barry R Holstein

The WKB approximation is demonstrated to be formally identical to the semiclassical limit of the Feynman path integral propagator. In the limit that the path integral propagator is dominated by the classical particle trajectory, it is identical to the propagator calculated directly from WKB wave functions in the stationary phase approximation.

Effects Of Earthquake On Traditional Houses Of Kathmandu, Bhishna Bajracharya

Bhishna Bajracharya

Asymptotic Theory Of Perturbed General Disconjugate Equations, William F. Trench

William F. Trench

No abstract provided.