1,087 research outputs found

    Electro-osmosis on anisotropic super-hydrophobic surfaces

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    We give a general theoretical description of electro-osmotic flow at striped super-hydrophobic surfaces in a thin double layer limit, and derive a relation between the electro-osmotic mobility and hydrodynamic slip-length tensors. Our analysis demonstrates that electro-osmotic flow shows a very rich behavior controlled by slip length and charge at the gas sectors. In case of uncharged liquid-gas interface, the flow is the same or inhibited relative to flow in homogeneous channel with zero interfacial slip. By contrast, it can be amplified by several orders of magnitude provided slip regions are uniformly charged. When gas and solid regions are oppositely charged, we predict a flow reversal, which suggests a possibility of huge electro-osmotic slip even for electro-neutral surfaces. On the basis of these observations we suggest strategies for practical microfluidic mixing devices. These results provide a framework for the rational design of super-hydrophobic surfaces.Comment: 4 pages, 4 figures; submitted to PRL Revised version: several references added, typos corrected. Supplementary file was restructured, the second part of the original EPAPS was removed and is supposed to be published as a separate pape

    Reaction of trimethyl phosphite with benzylidenebenzoylacetic ester

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    1. Trimethyl phosphite reacts with benzylidenebenzoylacetic ester to give 2,2,2-trimethoxy-3,5-di-phenyl-4-carbethoxy-1-oxa-2-phospha-4-cyclopentene (I). 2. When (I) is reacted with water and acetic anhydride the opening of the phosphorane ring occurs at the P-O bond. Phosphorane (I) is stable toward alcohol. 3. The structure of all of the obtained products was confirmed by the IR spectra. © 1971 Consultants Bureau

    Interannual variability of the Black Sea Proper oxygen and nutrients regime: The role of climatic and anthropogenic forcing

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    The Black Sea is a unique, stratified, enclosed ocean basin of great importance. The water column provides a wealth of information concerning aerobic-anaerobic biogeochemistry, the responses of which can have links to anthropogenic and climatic forcing. Herein, we synthesize dissolved oxygen (DO) and nutrient data (phosphate, dissolved inorganic nitrogen (DIN), and silicate) for the period 1984-2010 received in the northeastern and western areas of the Sea. In the subsequent analysis we discuss the role of anthropogenic and climatic forcing in the context of the Black Sea oxic layer and oxic/anoxic interface characteristics.The DO concentration in the surface layer and in the Cold Intermediate Layer (CIL) decreased in warm periods and increased in cold periods, correlating to North Atlantic Oscillation (NAO) index variation. The biogeochemical regime of the Black Sea oxygenated upper layer has notably changed since 1999. After 1999 DO concentration in the CIL decreased by 20% while the concentrations in the surface layer changed very little. This provides evidence that the CIL waters were not fully replenished during the winters of the last decade.The nutrient concentrations (DIN and phosphate) in the surface layer decreased significantly in the 2000s compared with the 1980s-1990s. This decrease is regarded as improvement of the Black Sea ecosystem state. Oxygen and nutrient dynamics in the middle pycnocline have been decoupled since 1999. Presently physical (climatic) forcing is the dominant affecting factor controlling the Sea oxygen and nitrogen regime. © 2013 Elsevier Ltd

    Reaction of trimethyl phosphite with ethyl benzylideneacetoacetate

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    1. Trimethyl phosphite reacts with ethyl benzylideneacetoacetate forming 2,2,2-trimethoxy-3-phenyl-4-carbethoxy-5-methyl-l-oxa-2-phosphacyclopentene-4. 2. Reactions of the above phosphorane with water, methanol, and acetic anhydride were investigated. 3. The structure of all the products obtained was verified by special methods. © 1969 Consultants Bureau

    Reaction of 2,5-diphenyl-3,4-diazacyclopentadien-1-one 3,4-dioxide with trialkyl phosphites

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    The trimethyl and triethyl phosphite react with 2,5-diphenyl-3,4-diazacyclopentadien-1-one 3,4-dioxide to give 1-alkyl-3,5-diphenyl-4-pyrazolyl dialkyl phosphates. © 1973 Consultants Bureau

    Reaction of dimethyl ester of 1-phenyl-2-acetyl-2-carbethoxyethylphosphonic acid with hydroxylamine hydrochloride and phenylhydrazine

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    1. The dimethyl ester of 1-phenyl-2-acetyl-2-carbethoxyethylphosphonic acid reacts with hydroxyl-amine hydrochloride at room temperature to give the dimethyl ester of 1-phenyl-2-carbethoxy-3-hydroxyl-amino-2-butylenephosphonic acid, while when heated on the water bath the corresponding oxime is formed. 2. The corresponding phenylhydrazone was obtained when the dimethyl ester of 1-phenyl-2-acetyl-2-carbethoxyethylphosphonic acid was reacted with phenylhydrazine. © 1971 Consultants Bureau

    Nonlinear acoustic waves in channels with variable cross sections

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    The point symmetry group is studied for the generalized Webster-type equation describing non-linear acoustic waves in lossy channels with variable cross sections. It is shown that, for certain types of cross section profiles, the admitted symmetry group is extended and the invariant solutions corresponding to these profiles are obtained. Approximate analytic solutions to the generalized Webster equation are derived for channels with smoothly varying cross sections and arbitrary initial conditions.Comment: Revtex4, 10 pages, 2 figure. This is an enlarged contribution to Acoustical Physics, 2012, v.58, No.3, p.269-276 with modest stylistic corrections introduced mainly in the Introduction and References. Several typos were also correcte

    Resting-state functional connectivity in deaf and hearing individuals and its link to executive processing

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    Sensory experience shapes brain structure and function, and it is likely to influence the organisation of functional networks of the brain, including those involved in cognitive processing. Here we investigated the influence of early deafness on the organisation of resting-state networks of the brain and its relation to executive processing. We compared resting-state connectivity between deaf and hearing individuals across 18 functional networks and 400 ROIs. Our results showed significant group differences in connectivity between seeds of the auditory network and most large-scale networks of the brain, in particular the somatomotor and salience/ventral attention networks. When we investigated group differences in resting-state fMRI and their link to behavioural performance in executive function tasks (working memory, inhibition and switching), differences between groups were found in the connectivity of association networks of the brain, such as the salience/ventral attention and default-mode networks. These findings indicate that sensory experience influences not only the organisation of sensory networks, but that it also has a measurable impact on the organisation of association networks supporting cognitive processing. Overall, our findings suggest that different developmental pathways and functional organisation can support executive processing in the adult brain
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