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91.
Eva M. Maya Arthur W. Snow Leonard J. Buckley 《Journal of polymer science. Part A, Polymer chemistry》2003,41(1):60-67
A synthesis procedure for and characterization of a tetra‐ortho‐methyl substituted three‐ringed cyanate ester monomer, 4,4′‐[1,3‐phenylenebis(1‐methylethylidene)]bis[2,6‐dimethyl]phenylcyanato, and the corresponding cured resin are described with comparative characterization of the resin analogue without the ortho‐methyl substitutents. The othro‐methylation lowered the dielectric from 2.64 to 2.59 at 1 GHz and from 2.64 to 2.48 GHz at 15 GHz, whereas the tan δ was not significantly affected. Other physical properties also affected included a 40 °C decrease in the glass‐transition temperature, an increase in the thermal‐expansion coefficients, and a reduction in thermogravimetric stability. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 60–67, 2003 相似文献
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94.
Fred Buckley 《Journal of Graph Theory》1982,6(3):317-324
An island decomposition of a graph G consists of a set of vertex-disjoint paths which cover the vertex set of G. If the endpoints of the paths are mutually nonadjacent, then we have an atoll decomposition. We characterize graphs requiring two paths in an island decomposition yet having no atoll decomposition. Results are given relating atoll decompositions to cutpoints and Hamiltonian blocks. 相似文献
95.
A. Burger D. J. Abraham J. P. Buckley W. J. Kinnard 《Monatshefte für Chemie / Chemical Monthly》1964,95(6):1721-1728
Zusammenfassung Die Synthese von 4-Dialkylaminoacetyl-[2,2]-paracyclophanen, der entsprechenden Aminoalkohole, von 1-(2-N,N-Diäthylamino-äthoxy)-1-(4-[2,2]-paracyclophan), und 4-([2,2]-Paracyclophanyl)-penicillin wird beschrieben. Eine biologische Auswertung zeigt, daß die Eigenschaften dieser Substanzen, im Vergleich zu denen analoger bekannter Benzolderivate, qualitativ den Erwartungen entsprechen.
Herrn Professor Dr.Hermann Bretschneider zum 60. Geburtstag in Freundschaft gewidmet.
This study was supported, in part, by a Grant, NB-01445, from the Institute of Neurological Diseases and Blindness, National Institutes of Health, U. S. Public Health Service. 相似文献
The synthesis of 4-dialkylaminoacetyl-[2,2]-paracyclophane derivatives and of the corresponding amino alcohols is described, as well as that of 4-([2,2]paracyclophanyl)-penicillin. Evaluation of these compounds demonstrated that their biological properties are qualitatively like those of analogous known benzene derivatives.
Herrn Professor Dr.Hermann Bretschneider zum 60. Geburtstag in Freundschaft gewidmet.
This study was supported, in part, by a Grant, NB-01445, from the Institute of Neurological Diseases and Blindness, National Institutes of Health, U. S. Public Health Service. 相似文献
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This paper presents a preliminary structural and interfacial study of the iron chalcogenide glass [i.e., Fex(Ge28Sb12Se60)100−x] ion-selective electrode (ISE) using small angle neutron scattering (SANS) and electrochemical impedance spectroscopy (EIS). SANS detected variations in the neutron scattering as a function of iron content in the chalcogenide glass. Furthermore, a change in the chalcogenide glass structure was observed at elevated iron dopant levels. Conversely, EIS was used to show that the iron chalcogenide membrane comprises various time constants, and the interfacial charge transfer reaction depends on the membrane iron content. Equivalent circuit modeling revealed that the charge transfer resistance decreases at elevated iron levels, and this may be related to the presence of iron defects in the glass. It is proposed that the iron chalcogenide membrane comprises an iron nanostructural network embedded in the amorphous matrix, and this directly influences the electrical conductivity and concomitant electrochemical reactivity of the glass. 相似文献
98.
Voth GA Bigger B Buckley MR Losert W Brenner MP Stone HA Gollub JP 《Physical review letters》2002,88(23):234301
Fluid-mediated interactions between particles in a vibrating fluid lead to both long range attraction and short range repulsion. The resulting patterns include hexagonally ordered microcrystallites, time-periodic structures, and chaotic fluctuating patterns with complex dynamics. A model based on streaming flow gives a good quantitative account of the attractive part of the interaction. 相似文献
99.
Interferences (overlaps) occurring when lines of other elements affect either peak or background measurements can cause errors
in quantitative WD analysis, but may be minimised by suitable choices of analysis conditions such as spectrometer crystal,
background offsets, and pulse-height analyser settings. Computer spectrum-simulation is much more effective than reference
to wavelength tables for investigating interferences. The ‘Virtual WDS’ simulation program developed by the present authors,
hitherto applied only to ‘ordinary’ elements (Z ≥ 11), has been extended to light elements for which evaporated multilayers are used in place of true crystals. ‘Virtual
WDS’ utilises experimentally recorded light-element K spectra and L and M spectra of heavier elements in the same wavelength
range. It is impractical to record all high-order peaks, so computed line profiles are used, with widths and intensities interpolated
from a limited set of observations. The relative positions of first and higher order peaks are affected significantly by the
refractive index of the multilayer, requiring modification of the Bragg equation. Suppression of high orders by pulse-height
analysis is less effective than for ‘normal’ wavelengths, owing to the breadth of the pulse-height distribution for low X-ray
energies. Simulation using a Gaussian expression aids optimisation of threshold and window-width settings. 相似文献
100.