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91.
Henry T. Kalinoski Leonard O. Hargiss 《Journal of the American Society for Mass Spectrometry》1992,3(2):150-158
Direct injection from a capillary supercritical fluid chromatography system was used as an inlet technique for chemical ionization (CI) and low energy collision-induced dissociation (CID) mass spectrometry of a series of low volatility nonionic surfactant mixtures. Characteristic fragment ions produced by CID for various classes of nonionic surfactant molecules were found to depend greatly on the structure of the surfactant hydrophobe. This was the case even when the charge on the molecule appeared localized away from the hydrophobe. Numerous decomposition pathways are suggested by the fragment ions produced. The use of direct supercritical fluid injection as an inlet technique does not appear to influence adversely the ability to produce cm mass spectra. Direct supercritical fluid introduction allows CI to be compared with other ionization mechanisms more commonly used for multifunctional, low volatility samples. 相似文献
92.
Leonard J. Schulman 《Positivity》2009,13(3):559-574
Muirhead’s majorization inequality was extended by Rado to the case of arbitrary permutation groups. We further generalize
this inequality to compact groups and their linear representations over the reals. We characterize saturation of the inequality,
and describe the saturation condition in detail for the case of actions on Hermitian operators.
Supported in part by the National Science Foundation and the Center for the Mathematics of Information. 相似文献
93.
Aarne Kasikov Alar Gerst Arvo Kikas Leonard Matisen Agu Saar Aivar Tarre Arnold Rosental 《Central European Journal of Physics》2009,7(2):356-362
The resistive response of atomic layer deposited thin epitaxial α-Cr2O3(0 0 1) films, to H2 and CO in air, was studied. The films were covered with Pt nanoislands formed by electron-beam evaporation of a sub-monolayer
amount of the material. The gas measurements were performed at 250°C and 450°C. These temperatures led to different proportion
of chemical states, Pt2+ and Pt4+, to which the Pt oxidized. The modification was ascertained by the X-ray photoelectron spectroscopy method. As a result of
the modification, the response was fast at 250°C, but slowed at 450°C. A disadvantageous abundance of Pt4+ arising at 450°C in air could be diminished by high-vacuum annealing thus restoring the response properties of the system
at 250°C.
相似文献
94.
Atkinson IM Chartres JD Groth AM Lindoy LF Lowe MP Meehan GV 《Chemical communications (Cambridge, England)》2002,(20):2428-2429
A new second generation dendrimer incorporating nine S2N2-donor macrocyclic units that bind nine Pd(II) cations is reported. 相似文献
95.
Removal of or replacement of one of two phenylethyl sidearms on azalariats leads to clear evidence for cation-pi interactions with the remaining sidearm. 相似文献
96.
97.
The cation N(2)H(7)(+) has been stabilized in a largely hydrophobic supramolecular environment and characterized in the solid state. The cation is situated in the bowl-shaped cavity of calix[4]arene. All of the hydrogen atoms are clearly discernible owing to high-quality X-ray data as well as lack of disorder and symmetry-imposed ambiguity. It appears that electrostatic interactions play a critical role in stabilizing the structure. 相似文献
98.
99.
J. Leonard und S. L. Malhotra 《Colloid and polymer science》1978,256(7):716
Ohne Zusammenfassung 相似文献
100.
Leonard I. Grossweiner 《Photochemistry and photobiology》1968,8(5):411-417
Abstract— The current status of research on sensitized photoconductive effects in zinc oxide is reviewed. The various types of chemical and spectral photosensitization processes observed in polycrystalline specimens can be explained qualitatively with a generalized electron acceptor molecule (EAM) model. in which electronegative surface agents trap zinc oxide conduction electrons in the dark and illumination causes a release of the trapped electrons. The EAM may be an adsorbed gas or vapor, adsorbed dye molecules, or an aggregated dye film, depending on the particular photoeffect. 相似文献