1,720,956 research outputs found
VIBRATIONAL SPECTRA OF THE PHTHALONITRILES
No full textAuthor Institution: National Bureau of StandardsSolid state spectra for samples of 1,2-, 1,3-, and 1,4--dicyanobezenes have been recorded in the 5000--260 region using prism-grating and prism spectromenters. Comparisons will be made with the spectra of other disubstituted benzenes in the long wavelength region. A detailed analysis of the vibrational spectra is being undertaken and some tentative assignments are suggested
VIBRATIONAL SPECTRA AND ASSIGNMENTS FOR PHENAZINE
No full textAuthor Institution: Department of Chemistry, Rensselaer Polytechnic InstituteInfrared and Raman spectra of phenazine have been obtained. Vibrational assignments based on the observed spectra, analogy with anthracene, and normal coordinate analysis will be reported. Comparison of the spectra of phenazine and phenazine dioxide will be given
VIBRATIONAL SPECTRA OF QUINOLINE AND ISOQUINOLINE.
No full textAuthor Institution: Department of Chemistry, Rensselaer Polytechnic InstituteAssignments for all of the fundamentals of quinoline and isoquinoline will be reported and compared with those for napththalene. The frequencies have also been calculated using a set of force constants transferred from related molecules and discussion of the modification of the Urey-Bradley force field for aromatic molecules will be included. Present address of John C. McNerney: Department of Chemistry, U.S. Military Academy, West Point, New York
ELECTRONIC AND VIBRATIONAL SPECTRA OF 1,6- AND 1,8 -NAPHTHYRIDINES
No full textAuthor Institution: Department of Chemistry, Rensselaer Polytechnic InstituteThe fundamental vibrational frequencies of 1,6- and 1,8- naphthyridines have been assigned from observed spectra, normal coordinate analysis and comparison with related molecules. Discussion of trends in normal vibrations as a function of position of the heteroatoms in azanaphthalenes will be given. Tentative assignment of the electronic spectrum of 1,6-naphthyridine will be given based on vapor studies in the fifteenth order using a Jarrell-Ash 3.4 meter spectrograph
THE ELECTRONIC SPECTRUM OF PYRAZINO (2,3-B) PYRAZINE
No full textAuthor Institution: Department of Chemistry, Rensselaer Polytechnie InstituteThe ultraviolet spectrum of pyrazino (2,-3-b) pyrazine shows a n transition at 412 ma and a transition originating at about 3200 \AA. The vapor spectrum reveals an apparent origin at . Details of the vibronic structure will be discussed. Present address of John Youker: Hudson Valley Community College, Troy, New York, 12180
ELECTRONIC AND VIBRATIONAL SPECTRUM OF 1,5-NAPHTHYRIDINE
No full textAuthor Institution: Department of Chemistry, Rensselaer Polytechnic InstituteFundamental vibrational frequencies of the ground state of 1,5-naphthyridine are assigned. A normal coordinate analysis was performed to test the assignments. The electronic spectrum of 1,5-naphthyridine vapor was obtained. transition having an origin at 27 785 appears to be superimposed on a continuum. A long progression in is assigned together with other vibronic bands and sequences in 9.5, 14.5, and . Present address of Newton M. Perrins: Division of Laboratories and Research, New York State Department of Health, Albany, New York 1220
Surface analysis and adhesion in fluoropolymer
No full textMay 1976School ofA semi-empirical way to elucidate adhesive bonding phenomena is based on the surface analysis method guided by qualitative fracture mechanics theory. The latter emphasizesinherent flaws, viscoelastic and
plastic response of materials, crazing, crack propagation and interfacial separation; our method determines the extent of each mechanism. In untreated fluoropolymers, surface molecules transfer to the adhesive even though bond strength is negligible. Surface treatment increases the surface energy via a hydrocarbon layer, the thickness of which varies from ~20A ("Teflon" FEP, Type C or gold-crystallized) to >500A with sodium etching. Increased adhesive bond strength is equivalent and
fracture occurs relatively deep in the fluoropolymer with an amount of plastic deformation related to strength. When the surface treatment is depleted by heat or light, bond strength varies with surface composition.
Cohesive failure occurs in both "Teflon" FEP and "Teflon" PFA used as hot-melt adhesives, but FEP separates much closer to the substrate and with little deformation compared with PFA, which helps to explain the order of magnitude greater strength of the latter.This method of surface characterization is especially useful for fluoropolymers because ESCA and contact-angle data clearly distinguish between fluorocarbon and hydrocarbons which are the usual components of
practical systems. Appreciable variations in surface properties occur depending upon fluoropolymer structure and whether formed by extruding from the melt, coating from aqueous dispersion, skiving from a sintered billet, or spraying and baking a thermoset blend enamel. ESCA reveals changes in the fluorocarbon/hydrocarbon ratio with variations in process conditions, and SEM shows effects on roughness. The receding contact angle best reflects changes in high surface-energy fraction. A remarkable, new surface(long fibers composed of -5000 parallel PTFE molecules) appears upon annealing.By combining x-ray photoelectron spectroscopy (ESCA), contactangle hysteresis, and electron microscopy, a powerful method to elucidate the nature of solid surfaces is created. ESCA provides
semi-quantitive elemental analysis of the uppermost tens of Angstrom units of the sample. A view of the microtopography is obtained with the electron microscope and contact-angle hysteresis can be interpreted in terms of the distribution of surface energies and roughness.Ph
THE VIBRATIONAL SPECTRA AND MOLECULAR STRUCTURE OF SOME HALOGENATED METHYL CYANIDES
No full textAuthor Institution: Department of Chemistry, Rensselaer Polytechnic InstituteThe series of halogenated methyl cyanides: , and , presents the interesting case where the substituent, X, in the group is progressively replaced by an atom of greater electronegativity. The present communication reports the infrared and Raman spectra and vibrational assignments for the fundamental bands of the molecules in this series. Comparison of the results clearly shows regularities in certain fundamentals ( stretch, symmetric and antisymmetric bends, symmetric and antisymmetric stretches) which may be attributed to the changes in the force field caused by increasing electronegativity of the group. Force constants are calculated for molecules belonging to the point group by the Wilson FG matrix method, the potential function containing all possible second degree terms. The limits of the invariancy of the force constants are examined in this series
Materials for a high temperature coal-based process to produce electrolytically pure hydrogen
No full textAugust 1976School of ScienceA unique process to produce electrolytically pure hydrogen in a chemically driven cell requires a ceramic membrane material with special properties. Under specific high temperature (800°C-1000°C) and low oxygen pressure (between 10-12 atm and 10-20 atm) conditions, the material must conduct both oxygen ions and electrons, be thermally and chemically stable, and capable of fabrication as a thin gas-tight membrane. A wide variety of materials were synthesized and evaluated for this application, including fluorite structure oxides based on both Ce02 and Y203-stabilized Zr02, perovskite-related oxides, and Bi 203-based materials.Ph
A systems biology approach for understanding osmotic stress in antibody-producing cell lines
No full textAugust 2009School of ScienceCenter for Biotechnology and Interdisciplinary StudiesPh
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