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151.
152.
Horozov TS Aveyard R Clint JH Neumann B 《Langmuir : the ACS journal of surfaces and colloids》2005,21(6):2330-2341
Vertical emulsion films with particle monolayers at their surfaces have been studied by direct microscope observations. The effects of particle wettability and surface coverage on the structure and stability of water films in octane and octane films in water have been investigated. Monodisperse silica particles (3 microm in diameter) hydrophobized to different extents have been used. It is found that the structure and stability of emulsion films strongly depend on the film type (water-in-oil or oil-in-water), the particle contact angle, the interactions between particles from the same and the opposite monolayer, and the monolayer density. Stable films are observed only when the particle wettability fulfills the condition for stable particle bridges--in agreement with the concept that hydrophilic particles can give stable oil-in-water emulsions, whereas hydrophobic ones give water-in-oil emulsions. In the case of water films with dilute disordered monolayers at their surfaces, the hydrophilic particles are expelled from the film center toward its periphery, giving a dimple surrounded by a ring of particles bridging the film surfaces. In contrast, the thinning of octane films with dilute ordered monolayers at their surfaces finally leads to the spontaneous formation of a dense crystalline monolayer of hydrophobic particles bridging both surfaces at the center of the film. The behaviors of water and octane films with dense close-packed particle monolayers at their surfaces are very similar. In both cases, a transition from bilayer to bridging monolayer is observed at rather low capillary pressures. The implications of the above finding for particle stabilized emulsions are discussed. 相似文献
153.
Bernd BrodbeckBernd Püllmann Sébastien SchmittMatthias Nettekoven 《Tetrahedron letters》2003,44(8):1675-1678
The parallel iterative solution-phase synthesis of 5-amino-1-aryl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylic acid amide derivatives is described. The key intermediate 2,6-bis-aminopyridine-4-carboxylic acid methyl ester was synthesised in a two step procedure in 64% overall yield and elaborated to a variety of triazolopyridine-5-carboxylic acid methyl ester by selective pyridine-N-amination, condensation of the adduct with a wide selection of aldehydes and subsequent cyclisation and oxidation. The desired esters were obtained in yields up to 70%. The final transformation to the amide derivatives was accomplished by application of carefully optimised reaction conditions thus giving access to a library of total 500 triazolopyridine amide derivatives. Iterative synthetic cycles (12-48 library members each) allowing for maximal flexibility in chemistry and maximal efficiency in in vitro biological activity optimisation guided by molecular modelling efforts constitute a synergistic procedure for rapid lead optimisation. 相似文献
154.
We investigate the nature of the phase transition from the superconducting to the uniformly ordered magnetic phase in ferromagnetic superconductors by renormalization group methods. For this purpose Halperin, Lubensky, Ma's application of the-expansion to pure superconductors is extended to include the influence of magnetic order as well. Our treatment shows that in the vicinity of the ferromagnetic to superconducting phase-boundary critical fluctuations of the magnetization are absorbed into fluctuations of the magnetic field. As a consequence the transition always is first order. An additional indication to the dominance of electromagnetic effects is the irrelevance of the coupling corresponding to spin flip scattering. 相似文献
155.
Thep-state pairing idea proposed recently to explain the ferromagnetism of ZrZn2 is described in more detail, and the underlying soft-mode hypothesis is examined in relation with experiments, in particular the discovery of antiferromagnetism in TiBe2. The key result, namely an electron-phonon contribution to the Stoner factor given essentially by the mass enhancement factor, is used to explain the behaviour of the Curie pointT
m
and to predict an isotope effect.p-state superconductivity with a transition temperature determined by is predicted in TiBe2 and, above the critical pressure whereT
m
=0, also in ZrZn2.Work in La Jolla supported by NSF/DMR 77-08469. 相似文献
156.
LetG denote a locally compact abelian topological group. The aim of the present paper is to prove an “intermediate” result between two well-known results ofL. Hörmander andG. I. Gaudry concerning the structure of the spaces ?G?μ?t p,q (G). 相似文献
157.
Dr. Bernd M. Schmidt Dr. Takafumi Osuga Dr. Tomohisa Sawada Dr. Manabu Hoshino Prof. Dr. Makoto Fujita 《Angewandte Chemie (International ed. in English)》2016,55(4):1561-1564
Self‐assembled coordination cages can be employed as a molecular press, where the bowl‐shaped guest corannulene (C20H10) is significantly flattened upon inclusion within the hydrophobic cavity. This is demonstrated by the pairwise inclusion of corannulene with naphthalene diimide as well as by the dimer inclusion of bromocorannulene inside the box‐like host. The compressed corannulene structures are unambiguously revealed by single‐crystal X‐ray analysis. 相似文献
158.
159.
Bernd Tieke Volker Enkelmann Harald Kapp Günter Lieser Gerhard Wegner 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(5):1045-1058
Abstract The topochemical polymerization of diacetylenes and.the dimerization of cinnamic acid derivatives have been studied in Langmuir-Blodgett-multilayers. The resulting polymer films are of controlled thickness and morphology and exhibit excellent stability. Structure, morphology and phase changes occuring in monomer and polymer films have been investigated using spectroscopic methods, electron and x-ray diffraction. Possible applications of the polymer films are discussed. 相似文献
160.
JPC – Journal of Planar Chromatography – Modern TLC - 相似文献