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51.
Innocenzi P Kidchob T Bertolo JM Piccinini M Guidi MC Marcelli C 《The journal of physical chemistry. B》2006,110(22):10837-10841
Rapid scan time-resolved infrared spectroscopy has been used to investigate in situ the kinetics of the chemical processes involved in the formation of self-assembled mesostructured films. The experiments have been done in transmission mode on films cast on a diamond disk using an infrared microscope. Two specific materials have been studied: silica and titania mesoporous films templated by a triblock copolymer surfactant (Pluronic F-127). The time dependence of solvent evaporation and condensation of the chemical species have been clearly observed. Different stages in the film formation have been identified, which support well the general theory of self-assembly. The in situ FTIR spectroscopy using time-resolved rapid scan has proven to be a very effective tool for in situ analysis of film formation from a liquid phase. 相似文献
52.
Stephen Clark Johnny Henderson 《Journal of Mathematical Analysis and Applications》2006,322(1):468-476
For the third order differential equation, y?=f(x,y,y′,y″), where f(x,y1,y2,y3) is Lipschitz continuous in terms of yi, i=1,2,3, we obtain optimal bounds on the length of intervals on which there exist unique solutions of certain nonlocal three and four point boundary value problems. These bounds are obtained through an application of the Pontryagin Maximum Principle from the theory of optimal control. 相似文献
53.
Johnny Henderson H. B. Thompson 《Proceedings of the American Mathematical Society》2000,128(8):2373-2379
For the second order boundary value problem, , , , where growth conditions are imposed on which yield the existence of at least three symmetric positive solutions.
54.
A new 8 ‐pulse P hase M odulated binomial‐like selective inversion pulse sequence, dubbed ‘8PM’, was developed by optimizing the nutation and phase angles of the constituent radio‐frequency pulses so that the inversion profile resembled a target profile. Suppression profiles were obtained for both the 8PM and W5 based excitation sculpting sequences with equal inter‐pulse delays. Significant distortions were observed in both profiles because of the offset effect of the radio frequency pulses. These distortions were successfully reduced by adjusting the inter‐pulse delays. With adjusted inter‐pulse delays, the 8PM and W5 based excitation sculpting sequences were tested on an aqueous lysozyme solution. The 8 PM based sequence provided higher suppression selectivity than the W5 based sequence. Two‐dimensional nuclear Overhauser effect spectroscopy experiments were also performed on the lysozyme sample with 8PM and W5 based water signal suppression. The 8PM based suppression provided a spectrum with significantly increased (~ doubled) cross‐peak intensity around the suppressed water resonance compared to the W5 based suppression. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
55.
56.
Lubomir Janda Johnny Nguyen Steven E. Patterson Lucjan Strekowski 《Journal of heterocyclic chemistry》1992,29(7):1753-1756
A tert-butoxide base-mediated cyclization of fluoro- and trifluoromethyl-substituted Schiff bases 12-19 produces 4-tert-butoxyquinolines 23-30 which are hydrolyzed to quinolin-4-ols 31-38 . 相似文献
57.
The Structure of [HSi9]3− in the Solid State and Its Unexpected Highly Dynamic Behavior in Solution 下载免费PDF全文
Corinna Lorenz Florian Hastreiter Dr. Johnny Hioe Dr. N. Lokesh Dr. Stefanie Gärtner Prof. Dr. Nikolaus Korber Prof. Dr. Ruth M. Gschwind 《Angewandte Chemie (International ed. in English)》2018,57(39):12956-12960
We report on the first unambiguous detection of the elusive [HSi9]3? anion in solutions of liquid ammonia by various 29Si and 1H NMR experiments including chemical exchange saturation transfer (CEST). The characteristic multiplicity patterns of both the 29Si and 1H resonances together with CEST and a partially reduced 1H,29Si coupling constant indicate the presence of a highly dynamic Si8 entity and a Si?H moiety with slow proton hopping. Theoretical calculations corroborate both reorganization of Si8 on the picosecond timescale via low vibrational modes and proton hopping. In addition, in a single‐crystal X‐ray study of (K(DB[18]crown‐6))(K([2.2.2]crypt))2[ HSi9 ]?8.5 NH3, the H atom was unequivocally localized at one vertex of the basal square of the monocapped square‐antiprismatic cluster. Thus experimental studies and theoretical considerations provide unprecedented insight into both the structure and the dynamic behavior of these cluster anions, which hitherto had been considered to be rigid. 相似文献
58.
Verena Huber Laurie Muller Johnny Hioe Pierre Degot Didier Touraud Werner Kunz 《Molecules (Basel, Switzerland)》2021,26(24)
A water-free, ternary solvent mixture consisting of a natural deep eutectic solvent (NADES), ethanol, and triacetin was investigated concerning its ability to dissolve and extract curcumin from Curcuma longa L. To this purpose, 11 NADES based on choline chloride, acetylcholine, and proline were screened using UV–vis measurements. A ternary phase diagram with a particularly promising NADES, based on choline chloride and levulinic acid was recorded and the solubility domains of the monophasic region were examined and correlated with the system’s structuring via light scattering experiments. At the optimum composition, close to the critical point, the solubility of curcumin could be enhanced by a factor of >1.5 with respect to acetone. In extraction experiments, conducted at the points of highest solubility and evaluated via HPLC, a total yield of ~84% curcuminoids per rhizome could be reached. Through multiple extraction cycles, reusing the extraction solvent, an enrichment of curcuminoids could be achieved while altering the solution. When counteracting the solvent change, even higher concentrated extracts can be obtained. 相似文献
59.
F.T. Hioe 《Physics letters. A》2009,373(17):1506-1509
Exact expressions for the precession of a planet's orbit and for the deflection of light near a massive object are presented. 相似文献
60.