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1.
G. Leonhardt 《Mathematische Annalen》1882,19(4):578-587
Ohne Zusammenfassung 相似文献
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Leonhardt U 《Physical review letters》1995,74(21):4101-4105
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Electron impact mass spectra of straight chain, monounsaturated C12 to C18 acetates and alcohols have been shown to be useful in the indication of the double bond position on an empirical basis. The ratio of intensities of the m/z 55 and m/z 54 ions increases proportionately as the double bond is moved away from the acetate or alcohol functional group. The intensity of the m/z 61 ion also can be correlated with the double bond position. Results are generally accurate to ±1 carbon atom. 相似文献
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Two synthetic routes have been introduced and evaluated for the preparation of hydrophilic silica-based monoliths possessing surface-bound cyano functions. In one synthetic scheme, the silica monolith was reacted in a single step with 3-cyanopropyldimethylchlorosilane to yield a cyano phase referred to as CN-monolith. In a second synthetic route, the silica monolith was first reacted with gamma-glycidoxypropyltrimethoxysilane (gamma-GPTS), followed by a reaction with 3-hydroxypropionitrile (3-HPN) to give a stationary phase denoted CN-OH-monolith. Although the gamma-GPTS was intended to play the role of a spacer arm to link the 3-HPN to the silica surface, this spacer arm became an integral part of the hydrophilic stationary phase. Thus, the CN-OH-monolith can be viewed as a double-layered stationary phase (i.e., stratified phase) with a hydroxy sub-layer and a cyano top layer. Due to its stronger hydrophilic character, the CN-OH-monolith yielded higher retention and better selectivity than the CN-monolith. The CN-OH-monolith was demonstrated in the normal-phase capillary electrochromatography (CEC) of various polar compounds including phenols and chloro-substituted phenols, nucleic acid bases, nucleosides, and nitrophenyl derivatives of mono- and oligosaccharides. The CN-OH-monolith yielded a relatively strong electroosmotic flow over a wide range of mobile phase composition, thus allowing rapid separation of the polar compounds studied. 相似文献
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Residence time spectra and material distributions in an operating caprolactam production plant were measured by means of sodium 24, bromine 82 and technetium 99m. The results of the tracerexperiments contributed to an optimization of the plant. 相似文献
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John D. Harvey Stuart G. Murdoch Stephane Coen Rainer Leonhardt David Mechin Gordon K. L. Wong 《Optical and Quantum Electronics》2007,39(12-13):1103-1114
Optical parametric amplification is an important nonlinear process in photonic crystal fibres driven by the small effective area and the special dispersion characteristics of these fibres. Aside from its role in supercontinuum generation, parametric amplification can lead to efficient wavelength conversion, limited primarily by the uniformity of the diameter of currently available fibres. The related Bragg scattering process can be used for both wavelength conversion and optical switching, again limited by the physical characteristics of the fibres used. 相似文献