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111.
Effect of annealing on hydrophobic stability of plasma deposited fluoropolymer coatings 总被引:1,自引:0,他引:1
Arun Kumar Gnanappa Cian O'Murchu Frank Peters Syed A.M. Tofail 《Polymer Degradation and Stability》2008,93(12):2119-2126
Fluorinated amorphous carbon (a-C:F) films e.g. plasma polymerised perfluorocyclobutane have long attracted much consideration due to their low surface energy, hydrophobicity, low refractive index, good electrical and thermal insulation and good thermal stability. Although a-C:F films have many advantages, hydrophobic stability over time in air and water remains a major concern. In this study, the effects of weathering conditions on the hydrophobicity of fluorocarbon films prepared from perfluorocyclobutane precursors were examined using water contact angle measurements. It was found that the high initial hydrophobicity of as-deposited films degrades rapidly in humid conditions. The stability of hydrophobicity can be significantly improved when a suitable treatment such as annealing is employed. The mechanism of weathering was explained with the help of a number of morphological and chemical characterisation techniques such as Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS). In particular, XPS results demonstrated that a reduction in the overall amount of -CF3 radical, oxygenation of surface fluorides and the formation of an overlayer all influence the degradation of fluorocarbon in aquatic environment. 相似文献
112.
Kovalchuk M. V. Alekseeva O. A. Blagov A. E. Ilyushin G. D. Il’ina K. B. Konarev P. V. Lomonov V. A. Pisarevsky Yu. V. Peters G. S. 《Crystallography Reports》2019,64(1):6-10
Crystallography Reports - The potassium dihydrogen phosphate K(H2PO4) (KDP) cluster structures formed in aqueous solutions have been theoretically and experimentally investigated. Cluster modeling... 相似文献
113.
A relationship between the fractal dimension and scaling groups of unstable miscible displacements 总被引:3,自引:0,他引:3
A detailed two-dimensional flow visualization study was performed to examine the dynamics of viscous fingering in miscible
displacements. Detailed quantitative miscible displacement experiments using a microcomputer-based imaging workstation on
a variety of oil recovery fluid systems were performed. The effect of two dimensionless scaling groups, namely gravity number
and viscosity ratio, on the displacement behavior was investigated. Based on image analysis, the irregular fingering patterns
of the flow visualization experiments were analyzed for fractal characteristics. Results indicate that the areal sweep efficiency
of unstable miscible displacement follows a fractal scaling law with a fractal dimension and proportionality constant related
to the gravity number and the viscosity ratio. The study shows that the fractal dimension decreases with decreasing gravity
number and increasing viscosity ratio. This relationship was mapped by an artificial neural network model, which can be used
to estimate the fractal dimension and the proportionality constant of miscible displacements as functions of the two scaling
groups. These results have potential application in the mathematical modeling of unstable EOR displacements and in the scaling
of laboratory displacements to field conditions.
Received: 19 December 1999/Accepted: 26 January 2001 相似文献
114.
K.G. Winkels I.R. Peters F. Evangelista M. Riepen A. Daerr L. Limat J.H. Snoeijer 《The European physical journal. Special topics》2011,192(1):195-205
Instabilities of receding contact lines often occur through the formation of a corner with a very sharp tip. These dewetting
structures also appear in the technology of Immersion Lithography, where water is put between the lens and the silicon wafer
to increase the optical resolution. In this paper we aim to compare corners appearing in Immersion Lithography to those at
the tail of gravity driven-drops sliding down an incline. We use high speed recordings to measure the dynamic contact angle
and the sharpness of the corner, for varying contact line velocity. It is found that these quantities behave very similarly
for Immersion Lithography and drops on an incline. In addition, the results agree well with predictions by a lubrication model
for cornered contact lines, hinting at a generic structure of dewetting corners. 相似文献
115.
Aubert B Boutigny D Gaillard JM Hicheur A Karyotakis Y Lees JP Robbe P Tisserand V Palano A Pompili A Chen GP Chen JC Qi ND Rong G Wang P Zhu YS Eigen G Stugu B Abrams GS Borgland AW Breon AB Brown DN Button-Shafer J Cahn RN Clark AR Gill MS Gritsan AV Groysman Y Jacobsen RG Kadel RW Kadyk J Kerth LT Kolomensky YG Kral JF LeClerc C Levi ME Lynch G Oddone PJ Pripstein M Roe NA Romosan A Ronan MT Shelkov VG Telnov AV Wenzel WA Harrison TJ Hawkes CM Knowles DJ O'Neale SW Penny RC Watson AT 《Physical review letters》2002,88(22):221802
Flavor oscillations of neutral B mesons have been studied in e+e- annihilation data collected with the BABAR detector at center-of-mass energies near the upsilon(4S) resonance. The data sample used for this purpose consists of events in which one B0 meson is reconstructed in a hadronic decay mode, while the flavor of the recoiling B0 is determined with a tagging algorithm that exploits the correlation between the flavor of the heavy quark and the charges of its decay products. From the time development of the observed mixed and unmixed final states, we determine the B0-B-0 oscillation frequency deltamd to be 0.516+/-0.016(stat)+/-0.010(syst) ps-1. 相似文献
116.
Braun NA Ousmer M Bray JD Bouchu D Peters K Peters EM Ciufolini MA 《The Journal of organic chemistry》2000,65(14):4397-4408
The oxidative cyclization of a phenolic amide to a spirolactam has long been regarded as an "impossible" reaction, because exposure of the substrates to a variety of oxidants results in formation of spirolactones with consequent loss of the amine segment. We recently communicated that this heretofore unknown transformation may be achieved by oxidation of oxazoline analogues of phenolic and indolic amides. Herein, we provide full details of our work. 相似文献
117.
Moore BC Peters RW Glasberg BR 《The Journal of the Acoustical Society of America》1999,106(6):3539-3552
Psychometric functions for detecting increments or decrements in level of sinusoidal pedestals were measured for increment and decrement durations of 5, 10, 20, 50, 100, and 200 ms and for frequencies of 250, 1000, and 4000 Hz. The sinusoids were presented in background noise intended to mask spectral splatter. A three-interval, three-alternative procedure was used. The results indicated that, for increments, the detectability index d' was approximately proportional to delta I/I. For decrements, d' was approximately proportional to delta L. The slopes of the psychometric functions increased (indicating better performance) with increasing frequency for both increments and decrements. For increments, the slopes increased with increasing increment duration up to 200 ms at 250 and 1000 Hz, but at 4000 Hz they increased only up to 50 ms. For decrements, the slopes increased for durations up to 50 ms, and then remained roughly constant, for all frequencies. For a center frequency of 250 Hz, the slopes of the psychometric functions for increment detection increased with duration more rapidly than predicted by a "multiple-looks" hypothesis, i.e., more rapidly than the square root of duration, for durations up to 50 ms. For center frequencies of 1000 and 4000 Hz, the slopes increased less rapidly than predicted by a multiple-looks hypothesis, for durations greater than about 20 ms. The slopes of the psychometric functions for decrement detection increased with decrement duration at a rate slightly greater than the square root of duration, for durations up to 50 ms, at all three frequencies. For greater durations, the increase in slope was less than proportional to the square root of duration. The results were analyzed using a model incorporating a simulated auditory filter, a compressive nonlinearity, a sliding temporal integrator, and a decision device based on a template mechanism. The model took into account the effects of both the external noise and an assumed internal noise. The model was able to account for the major features of the data for both increment and decrement detection. 相似文献
118.
Sonochemical treatment of natural ground water at different high frequencies: preliminary results 总被引:5,自引:0,他引:5
Naturally occurring ground water polluted by highly volatile chlorinated compounds, with 1,2-dichloroethane as the main contaminant, was sonicated with high frequency ultrasound (361, 620 and 1086 kHz) in order to investigate if results from studies performed with single model compounds in water can be applied to a natural ground water. It was shown that the treated highly volatile halogenated hydrocarbons are almost completely destroyed by ultrasound in natural ground water within 60 min. It also transpired that the naturally occurring inorganic components and gases in the ground water play an important role. 相似文献
119.
Justin Peters 《Journal of Functional Analysis》1984,59(3):498-534
Given a C1-algebra and endomorphim α, there is an associated nonselfadjoint operator algebra + Xα, called the semi-crossed product of with α. If α is an automorphim, + Xα can be identified with a subalgebra of the C1-crossed product + Xα. If is commutative and α is an automorphim satisfying certain conditions, + Xα is an operator algebra of the type studied by Arveson and Josephson. Suppose S is a locally compact Hausdorff space, φ: S → S is a continuous and proper map, and α is the endomorphim of U=C0(S) given by α(?) = ? ō φ. Necessary and sufficient conditions on the map φ are given to insure that the semi-crossed product Z+XαC0(S) is (i) semiprime; (ii) semisimple; (ii) strongly semisimple. 相似文献
120.