Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Selected Works

Discipline
Institution
Keyword
Publication Year
Publication
File Type

Articles 21631 - 21660 of 21971

Full-Text Articles in Physical Sciences and Mathematics

A Highly Enantioselective Hydrolysis Of -3,5-Diacetoxycyclopent-1-Ene, Donald Deardorff, A. Matthews, D. Mcmeekin, Chris Craney Dec 1985

A Highly Enantioselective Hydrolysis Of -3,5-Diacetoxycyclopent-1-Ene, Donald Deardorff, A. Matthews, D. Mcmeekin, Chris Craney

Chris L. Craney

Exposure of -3,5-diacetoxycyclopent-1-ene () to the hydrolase enzyme acetylcholinesterase (from electric eel) affords In 94% yield 3()-acetoxy-5()-hydroxycyclopent-1-ene () with an e.e. of 96% (greater than 99% e.e. after one recrystallization).

Go to article

Positive Experiences With Software Metrics, Robert Yacobellis Dec 1985

Positive Experiences With Software Metrics, Robert Yacobellis

Robert H Yacobellis

No abstract provided.

Go to article

Nuclease Activity Of 1,10-Phenanthroline-Copper Ion: Reaction With Cgcgaattcgcg And Its Complexes With Netropsin And Ecori, Thomas Goyne, Michio Kuwabara, Chun Yoon, Theodore Thederahn, David Sigman Dec 1985

Nuclease Activity Of 1,10-Phenanthroline-Copper Ion: Reaction With Cgcgaattcgcg And Its Complexes With Netropsin And Ecori, Thomas Goyne, Michio Kuwabara, Chun Yoon, Theodore Thederahn, David Sigman

Thomas Goyne

No abstract provided.

Go to article

Electromagnetic And Isopin Breaking Effects Decrease Epsilon'/Epsilon, Jf Donoghue, E Golowich, Br Holstein, J Trampetic Dec 1985

Electromagnetic And Isopin Breaking Effects Decrease Epsilon'/Epsilon, Jf Donoghue, E Golowich, Br Holstein, J Trampetic

Barry R Holstein

No abstract provided.

Go to article

Chiral Perturbation-Theory Corrections To Kl-]-Gamma-Gamma, Jf Donoghue, Br Holstein, Ycr Lin Dec 1985

Chiral Perturbation-Theory Corrections To Kl-]-Gamma-Gamma, Jf Donoghue, Br Holstein, Ycr Lin

Barry R Holstein

No abstract provided.

Go to article

A Design Methodology For Software Quality, Robert Yacobellis Dec 1985

A Design Methodology For Software Quality, Robert Yacobellis

Robert H Yacobellis

No abstract provided.

Go to article

Solution Of Systems With Toeplitz Matrices Generated By Rational Functions, William F. Trench Dec 1985

Solution Of Systems With Toeplitz Matrices Generated By Rational Functions, William F. Trench

William F. Trench

No abstract provided.

Go to article

Extensions Of A Theorem Of Wintner On Systems With Asymptotically Constant Solutions, William F. Trench Dec 1985

Extensions Of A Theorem Of Wintner On Systems With Asymptotically Constant Solutions, William F. Trench

William F. Trench

No abstract provided.

Go to article

Splay Rigidity In The Diluted Central Force Elastic Network, Anthony Roy Day, A.-M. S. Tremblay, R. R. Tremblay Dec 1985

Splay Rigidity In The Diluted Central Force Elastic Network, Anthony Roy Day, A.-M. S. Tremblay, R. R. Tremblay

Anthony Roy Day

A Comment on the Letter by Wang and Harris, Phys. Rev. Lett. 55, 2459 (1985).

Go to article

On The Eigenvalue Problem For A Class Of Band Matrices Including Those With Toeplitz Inverses, William F. Trench Dec 1985

On The Eigenvalue Problem For A Class Of Band Matrices Including Those With Toeplitz Inverses, William F. Trench

William F. Trench

No abstract provided.

Go to article

Toward A Theory Of Strict "Claim" Liability: Warranty Relief For Advertising Representations, Wayne Lewis Dec 1985

Toward A Theory Of Strict "Claim" Liability: Warranty Relief For Advertising Representations, Wayne Lewis

Wayne Lewis

No abstract provided.

Go to article

(On The) Observability Of Cubic (P8) Octaphosphorus, Michael W. Schmidt, Mark S. Gordon Dec 1985

(On The) Observability Of Cubic (P8) Octaphosphorus, Michael W. Schmidt, Mark S. Gordon

Mark S. Gordon

A recent MNDO calculation predicts that the hypothetical P8 is more stable than the observed gas-phase species P4. The ab initio calculations reported here predict just the opposite but do establish that P8 is more stable than another experimentally known form, P2. The relative enthalpies (kcaljmol) are found to be as follows: 4P2, 72.4; 2P 4, 0; P8, 30.4. A force field analysis proves P8 has a cubic structure. The bond length, vibrational frequencies, and photoelectron spectrum of P8 are predicted.

Go to article

Equatorial F-Region Zonal Plasma Drifts, Bela G. Fejer, E. Kudeki, D. T. Farley Dec 1985

Equatorial F-Region Zonal Plasma Drifts, Bela G. Fejer, E. Kudeki, D. T. Farley

Bela G. Fejer

We have examined in detail the F region plasma drifts measured at Jicamarca, Peru, during 1978–1981, a period of high solar activity, and compared these drifts with Jicamarca data taken during periods of lower activity, as well as with other equatorial zonal neutral wind and plasma drift measurements. The increase in solar activity causes larger nighttime eastward plasma drifts at Jicamarca and delays the morning reversal time from eastward nighttime to westward daytime drifts. The radar data seem to be in good agreement with nighttime neutral wind measurements made by the DE-2 satellite, but are systematically smaller than spaced receiver …

Go to article

Advances In Synthetic Polymer Chemistry: New Polymer Types And New Directions, The Sixth Carl S. Marvel Symposium, Otto Vogl, Henry K. Hall Dec 1985

Advances In Synthetic Polymer Chemistry: New Polymer Types And New Directions, The Sixth Carl S. Marvel Symposium, Otto Vogl, Henry K. Hall

Otto Vogl

No abstract provided.

Go to article

Polymer Science In Japan: The Hokuriku District And The Remaining Universities Of Japan, Otto Vogl, Kiichi Takemoto Dec 1985

Polymer Science In Japan: The Hokuriku District And The Remaining Universities Of Japan, Otto Vogl, Kiichi Takemoto

Otto Vogl

No abstract provided.

Go to article

Specialty Polymers -Present And Future, Otto Vogl, Roger Epton Nov 1985

Specialty Polymers -Present And Future, Otto Vogl, Roger Epton

Otto Vogl

No abstract provided.

Go to article

Quantum Electrodynamics At Finite Temperature, Jf Donoghue, Br Holstein, Rw Robinett Oct 1985

Quantum Electrodynamics At Finite Temperature, Jf Donoghue, Br Holstein, Rw Robinett

Barry R Holstein

We present a systematic examination of finite temperature effects in quantum electrodynamics at one loop order. We calculate mass, charge, and wavefunction renormalization, demonstrate the running of the coupling constant at high temperatures, and study the renormalized vertex function and the energy momentum tensor. The confusion in the literature concerning the finite temperature corrections to the electron's magnetic moment is resolved. We also present the finite temperature effects in scalar electrodynamics. Throughout we stress the need to provide a well-defined method to observe a given quantity when interpreting the results of a calculation, and we suggest new techniques which incorporate …

Go to article

Behavior And Ecological Interactions Of Larval Odonata, Clay L. Pierce, Philip H. Crowley, Dan M. Johnson Oct 1985

Behavior And Ecological Interactions Of Larval Odonata, Clay L. Pierce, Philip H. Crowley, Dan M. Johnson

Clay L. Pierce

Enallagma aspersum and E. traviatum (Odonata: Coenagrionidae) are the most abundant larval odonates in Bays Mountain Park (Sullivan County, Tennessee, USA), although their spatial distributions are essentially nonoverlapping. E. traviatum coexists with insectivorous fish in a small lake, whereas E. aspersum is restricted to a small fishless pond nearby. Behavioral observations revealed that E. aspersum larvae were more active than E. traviatum, and tended to occupy more conspicuous positions. E. aspersum also engaged in more confrontations than E. traviatum, especially at higher density. In laboratorye xperimentsw ith juvenile bluegills( Lepomism acrochirusa) s predators,E . aspersum larvae were more vulnerable to …

Go to article

Spectral Properties Of Percolating Central Force Elastic Networks, Anthony Day, R. Tremblay, A.-M. Tremblay Sep 1985

Spectral Properties Of Percolating Central Force Elastic Networks, Anthony Day, R. Tremblay, A.-M. Tremblay

Anthony Roy Day

The exponent describing the low frequency spectrum of vibrations for the central force universality class is computed with both the Coherent Potential Approximation and numerical simulations. The results of both calculations agree surprisingly well.

Go to article

Reanalysis Of Higgs-Boson-Exchange Models Of Cp Violation, Jf Donoghue, Br Holstein Aug 1985

Reanalysis Of Higgs-Boson-Exchange Models Of Cp Violation, Jf Donoghue, Br Holstein

Barry R Holstein

We reexamine the value of ɛ'/ɛ in models where CP violation is due to the exchange of charged Higgs bosons. Previous work has been flawed by incorrect treatment of the chiral properties of weak amplitudes. We use the effective-chiral-Lagrangian framework to clear up these aspects. The resultant value of ɛ'/ɛ is estimated to be in the neighborhood of ɛ'/ɛ=-0.006, although this estimate could be off by a factor of two or three in either direction. This value is consistent with the present experimental bounds.

Go to article

Evaluation Of Electrochemical Kinetic Parameters Using The Bond-Henderson-Oldham Global Analysis, Dennis Evans, Mark Anderson Aug 1985

Evaluation Of Electrochemical Kinetic Parameters Using The Bond-Henderson-Oldham Global Analysis, Dennis Evans, Mark Anderson

Mark R. Anderson

No abstract is currently available.

Go to article

Interaction Of The Zonalwinds With The Equatorial Midnight Pressure Bulge In The Earth's Thermosphere: Empiricalevidence Of Momentum Balance, F. A. Herrero, H. G. Mayr, N. W. Spencer, A. E. Hedin, Bela G. Fejer Aug 1985

Interaction Of The Zonalwinds With The Equatorial Midnight Pressure Bulge In The Earth's Thermosphere: Empiricalevidence Of Momentum Balance, F. A. Herrero, H. G. Mayr, N. W. Spencer, A. E. Hedin, Bela G. Fejer

Bela G. Fejer

A minimum is observed at midnight in the time variation of averaged zonal winds measured in-situ near the equator at an average altitude of about 350 km, and we inquire whether observations of the equatorial midnight pressure bulge are consistent with this feature. The observed zonal wind maintains an eastward direction all night. It increases steadily in the early evening reaching a maximum of about 160 m/s at 2100 hrs local time (LT), dropping to a minimum of about 70 m/s around 2400 LT, then up to about 120 m/s around 0300 LT, decreasing thereafter and turning westward in the …

Go to article

Studies Of Silicon-Phosphorus Bonding, Kenneth J. Dykema, Thanh N. Truong, Mark S. Gordon Jul 1985

Studies Of Silicon-Phosphorus Bonding, Kenneth J. Dykema, Thanh N. Truong, Mark S. Gordon

Mark S. Gordon

Ab initio calculations are presented for several species containing a silicon-phosphorus bond. The types of bonding studied include "normal" single, double, and triple bonds, as well as an ylide-like structure. The latter is found to be much less strongly bound than the carbon analogue, with a smaller stretching force constant than that in silylphosphine. The insertions of silylene into the phosphine bond and of phosphinosilylene into H2 are discussed, with the former being illustrated using localized molecular orbitals along the intrinsic reaction coordinate (IRC). Silylene to silene isomerizations in both the closed-shell singlet and the lowest triplet states of SiPH3 …

Go to article

A Theoretical Study Of Fluorine Atom And Fluoride Ion Attack On Methane And Silane, Larry P. Davis, Larry W. Burggraf, Mark S. Gordon, Kim K. Baldridge Jul 1985

A Theoretical Study Of Fluorine Atom And Fluoride Ion Attack On Methane And Silane, Larry P. Davis, Larry W. Burggraf, Mark S. Gordon, Kim K. Baldridge

Mark S. Gordon

We have performed MNDO and ab initio calculations for reactions of fluorine atom attack on methane and silane and, in addition, fluoride ion attack on the same molecules in the case of MNDO. We modeled both substitution and abstraction reactions in each case. Results were compared with experimental data, where available. Comparisons show that MNDO usually does as well as the ab initio methods in reproducing experimental values for D.E's of these reactions, but MNDO predicts activation barriers too high in most cases. Nevertheless, MNDO does qualitatively agree with the ab initio result that, while carbon undergoes abstraction much more …

Go to article

N-Color Spin Models In The Large N Limit, Mehran Kardar, Miron Kaufman Jun 1985

N-Color Spin Models In The Large N Limit, Mehran Kardar, Miron Kaufman

Miron Kaufman

N color spin models are introduced and examined in the large N limit. The free energy and critical properties at the phase transition are studied. With relevant couplings between colors the transition becomes either first order or Fisher renormalized. With irrelevant couplings there is a crossover to first-order transitions through a nonclassical tricritical point. Connections are established between the N-color model, compressible systems, and systems with random impurities.

Go to article

The Intrinsic Reaction Coordinate And The Rotational Barrier In Silaethylene, Michael W. Schmidt, Mark S. Gordon, Michel Dupuis May 1985

The Intrinsic Reaction Coordinate And The Rotational Barrier In Silaethylene, Michael W. Schmidt, Mark S. Gordon, Michel Dupuis

Mark S. Gordon

The intrinsic reaction coordinate (IRC) is a minimum-energy pathway connecting reactants to products via the transition state. An improved algorithm for the determination of an IRC is presented. The method is illustrated for the rotation of the silicon-carbon double bond in silaethylene. This IRC shows all coordinates vary smoothly during the rotation from the planar to twisted structures, except for a slight pyramidalization at carbon. The rotational barrier is found to be about 37 kcaljmol, in good agreement with experimental estimates.

Go to article

Glass Formation And High Conductivity In The Ternary System Silver Iodide + Silver Arsenate (Ag3aso4) + Silver Metaphosphate (Agpo3): Host To Glassy .Alpha.-Silver Iodide?, Steve W. Martin, Alberto Schiraldi May 1985

Glass Formation And High Conductivity In The Ternary System Silver Iodide + Silver Arsenate (Ag3aso4) + Silver Metaphosphate (Agpo3): Host To Glassy .Alpha.-Silver Iodide?, Steve W. Martin, Alberto Schiraldi

Steve W. Martin

Wide regions of glass formation have been found in the ternary system xAgI + yAg,As04 + (1 - x - y)AgPO,. Glasses containing up to 75 mol 7% AgI can be formed in sections greater than 2 cm thick without signs of devitrification. Glass transition temperatures as high as 175 OC for glasses containing - 10 mol % AgI fall to -45 OC at the highest AgI content. An equivalent ratio of Ag1:N is defined and it is found that, for all glass-forming compositions, the electrical data as expressed in the Arrhenius form, u = A exp(-E,,/RT), log (./(a cm)-’), …

Go to article

Determining The Temperature-Dependent Characteristic Temperature Of Beryllium From Electrical Resistance Measurements, Thomas W. Listerman, Xiao-Li Zhou May 1985

Determining The Temperature-Dependent Characteristic Temperature Of Beryllium From Electrical Resistance Measurements, Thomas W. Listerman, Xiao-Li Zhou

Thomas Listerman

We have developed an intermediate-level laboratory experiment to determine the temperature- dependent characteristic temperature of beryllium. The apparatus used to measure the resistance of a beryllium wire sample between liquid nitrogen and room temperatures was simple. The characteristic temperatures obtained from these data using the Block-Grüneisen model are in reasonable agreement with literature values obtained from resistivity and heat capacity experiments. The experiment introduced students to cryogenic and computer data analysis techniques and forced them to extend their knowledge of the theory of electrical resistance and of characteristic temperatures.

Go to article

Electronic Structure Of The Phosphoryl And Thiophosphoryl Bonds, Michael W. Schmidt, Mark S. Gordon Apr 1985

Electronic Structure Of The Phosphoryl And Thiophosphoryl Bonds, Michael W. Schmidt, Mark S. Gordon

Mark S. Gordon

.The pho~phoryl bond is presented as a. resonan~e hybrid between singly and triply bound structures. The types of electromcally excited states and a number of their potential surfaces can be understood within the confines of a singly bound model: However, a detailed analysis of the electronic distribution within the ground state shows significant contribution from the tnpl~ bound structure. In fact, increasing the electronegativity of the ligands at phosphorus increases the contribution of t~e tnp~y bound structure, so that the. PO bond order approaches that of a double bond. The thiophosphoryl bond may be VIewed m much the same manner …

Go to article

Molecular And Electronic Structures Of Metallaspiropentanes, Mark S. Gordon, Philip Boudjouk Mar 1985

Molecular And Electronic Structures Of Metallaspiropentanes, Mark S. Gordon, Philip Boudjouk

Mark S. Gordon

Recent efforts in this laboratory have concentrated on synthesizing metallaspiropentane compounds (I) with M = C, Si, Ge, Sn, Ni, and Zn. To date, the molecule with M = Si and R = methyl has been successfully prepared, 1 while attempts to synthesize the corresponding carbon compound have not reached fruition. This paper presents initial ab initio calculations on the species with M = C and Si and with R = H. Geometries for all species were calculated with the

Go to article

First Prev Next Last