Mass spectrometry in structural and stereochemical problems. CXLIII.
Mass spectra peak of deuterium labeled aliphatic ethers involving hydrogen rearrangement during electron impact fragmentation
Carpenter, W.↗
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Kinetic theory of almost classical fluids.
Fokker-Planck equation with first order quantum correction extended to mixtures by rearranging terms, noting friction tensor role
Davis, H. T.↗
Cross-correlation and cross-spectral methods for drift velocity measurements.
Cross relation and cross spectral methods of computing drift velocity of structure undergoing internal rearrangement for remote solar wind observation
Bowles, K. L.↗
Mass spectrometry in structural and stereochemical problems. CXXXII.
Electron impact induced alkyl and aryl rearrangements in substituted cyclohexenones, bicyclic ketones and deuterium labeled analogs from mass spectra measurements
Djerassi, C.↗
Mass spectrometry in structural and stereochemical problems. CXXXVII - Examples of interaction of remote functional groups after electron impact.
Cyclic ketones containing methoxyl and hydroxyl studied for oxygen rearrangement on electron impact
Djerassi, C.↗
Fermi-surface structure and field ionization.
Field ionization at metal surfaces as rearrangement collision, considering anisotropic electron tunneling probabilities produced by Fermi surface
Fonash, S. J.↗
Mass spectrometry in structural and stereochemical problems. CLXXV
Evidence against electron impact induced alkyl shifts in mass spectra of alpha-hydroxy-ketones, showing thermal rearrangements
Brown, C. A.↗
FORTRAN 4 digital program changer
Computer program modifies other source language programs as aid to debugging, checkout and final documentation to eliminate manual performance of rearranging and incrementing statement numbers, identifying and sequencing cards and inserting and/or removing end-of-batch symbols.
Madden, M. F.↗
High-temperature molding of pyrrones
High temperature pyrrones molding, discussing covalent organic bonds breakage and subsequent structural rearrangement of crosslinked polymer network
Bagley, E. B.↗
Application of parameter optimization techniques to space shuttle thermal protection design
Space shuttle thermal protection system optimal weight by numerical parameterization, discussing temperature constraints and material rearrangement effects
Curry, D. M.↗
Flexible shielding system for radiation protection
Modular construction of low cost flexible radiation shielding panels consists of water filled steels cans, zinc bromide windows, turntable unit, master-slave manipulators, and interlocking lead bricks. Easy modifications of shielding wall thicknesses are obtained by rearranging overall geometry of portable components.
Babin, A.↗
Study of the techniques feasible for food synthesis aboard a spacecraft
Synthesis of sugars by Ca(OH)2 catalyzed formaldehyde condensation (the formose reaction) has produced branched carbohydrates that do not occur in nature. The kinetics and mechanisms of the homogeneously catalyzed autocatalytic condensation were studied and analogies between homogeneous and heterogeneous rate laws have been found. Aldol condensations proceed simultaneously with Cannizzaro and crossed-Cannizzaro reactions and Lobry de Bruyn-Van Eckenstein rearrangements. The separate steps as well as the interactions of this highly complex reaction system were elucidated. The system exhibits instabilities, competitive catalytic, mass action, and equilibrium phenomena, complexing, and parallel and consecutive reactions. Specific finding that have been made on the problem will be of interest for synthesizing sugars, both for sustained space flight and for large scale food manufacture. A contribution to methodology for studying complex catalyzed reactions and to understanding control of reaction selectivity was a broad goal of the project.
Weiss, A. H.↗
Heuristic theory of positron-helium scattering.
An error in a previous modified adiabatic approximation (Drachman, 1966), due to a lack of generality in the form of the short-range correlation part of the wave function for L greater than zero, is corrected heuristically by allowing the monopole suppression parameter to depend on L. An L-dependent local potential is constructed to fit the well-known positron-hydrogen s, p, and d wave phase shifts below the rearrangement threshold. The same form of potential yields a positron-helium cross-section in agreement with a recent experimental measurement near threshold.
Drachman, R. J.↗
Molecular beams in chemistry.
The molecular-beam technique is a means for producing isolated atoms or molecules within a narrow range of speed and solid angle. The phenomena studied with molecular beams can be classified as single-particle interactions, many-particle interactions, and two particle-interactions. The results of scattering experiments fall into two categories including collisions that do not result in atomic rearrangements and collisions that do. Experimental methods are discussed, giving attention to low-energy beams, high-energy beams, and intermediate-energy beams. Examples are presented to illustrate the information that can be obtained from elastic, inelastic, and reactive scattering.
Jordan, J. E.↗
Generalized pseudopotential approach for electron-atom scattering.
A generalized many-electron pseudopotential approach is presented for electron-neutral-atom scattering problems. A calculation based on this formulation is carried out for the singlet s-wave and p-wave electron-hydrogen phase shifts with excellent results. We compare the method with other approaches as well as discuss its applications for inelastic and rearrangement collision problems.
Zarlingo, D. G.↗
The lunar disturbance effect.
The observed phenomenon of darkening of the lunar surface when gently disturbed is investigated. It is suggested that this disturbance effect is due to changes in the photometric function of the lunar soil caused by rearrangement of the soil particles, rather than to any physical or chemical differences between the uppermost layer and the underlying materials.
Hapke, B. W.↗
The electron-impact promoted fragmentation of aurone epoxides.
The mass spectra of six aurone epoxides have been rationalized with the aid of high resolution mass spectrometry and metastable ion evidence. These compounds fragment in a well defined manner and mechanisms are proposed for the formation of their characteristic ions. Some similarity was observed between the mass spectra of 6-methoxyaurone epoxide (II), 4-hydroxy-7-methoxy-3-phenylcoumarin (VII) and 7-methoxyflavonol (IX). The possibility that VII and IX are intermediates in the fragmentation of epoxide II is discussed. Thermal rearrangement of aurone epoxide II was shown to yield the corresponding flavonol IX and coumarin VII.
Brady, B. A.↗
Fourier transform C-13 NMR analysis of some free and potassium-ion complexed antibiotics.
Fourier transforms of the noise-decoupled, natural abundance C-13 NMR free induction decays of the cyclic antibiotic valinomycin and its potassium-ion complex have been obtained at 25.2 MHz. Comparisons are made with C-13 NMR spectra taken at 22.6 MHz of the cyclic antibiotic nonactin and the synthetic polyether dicyclohexyl-18-crown-6 and their potassium complexes. The results obtained suggest that conformational rearrangements of the molecule as a whole can compete with direct interactions between carbons and the potassium ion in determining C-13 chemical shift differences between the free and complexed species.
Ohnishi, M.↗