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241.
242.
We have studied the equilibria of liquid droplets wetting a step edge with an opening angle
by a combination of analytical and numerical methods. Depending on the wetting properties of the substrate walls and on the liquid volume, different locally or globally stable liquid morphologies are found. Complete spreading of the liquid along the bottom edge of the step is observed at equilibrium contact angles
satisfying
. If the contact angle
exceeds a threshold value
the liquid exists in a blob-like configuration. Surprisingly, we find an intermediate regime at a sufficiently high liquid volume and in a range of contact angles
, in which cigar-shaped configurations arise in addition to the blob. We close the paper by a detailed discussion of the stability of this novel liquid morphology.PACS:
47.55.Dz Drops and bubbles - 61.30.Hn Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions - 68.08.Bc Wetting 相似文献
243.
Übersicht Für nicht-Newtonsche Flüssigkeiten, für die das Ostwald-de Waelesche Potenzreibungsgesetz gilt, werden die ebenen Grenzschichtdifferentialgleichungen aufgestellt und es wird ihre Gültigkeit diskutiert. Als exakte Lösungen der Differentialgleichungen für die Strömungs- und Temperaturgrenzschicht werden die ähnlichen Lösungen für die Keilströmungen behandelt. Mit den Ergebnissen der ähnlichen Lösungen werden Näherungsverfahren zum Berechnen der Strömungs- und Temperaturgrenzschichten aufgestellt.
Die vorhegende Arbeit entstand während der Assistenztätigkeit des Verfassers am Institut für Maschinenelemente und Fördertechnik der Technischen Hochschule Braunschweig (Direktor Prof. Dr.-Ing. O. Lutz) auf Anregung von Herrn Prof. Dr.-Ing. K. Gersten. Verfasser dankt den Herren Professoren Schlichting, Lutz und Gersten, die ihm die Durchführung dieser Arbeit ermöglichten. 相似文献
Summary A study of the laminar boundary layer equations of fluids governed by the Ostwald-de Waele. power law is presented. Using the similar solutions for flows past wedges, methods for the approximate solution of the laminar velocity and thermal boundary layer equations are presented for the case of laminar flow past arbitrary external surfaces.
Die vorhegende Arbeit entstand während der Assistenztätigkeit des Verfassers am Institut für Maschinenelemente und Fördertechnik der Technischen Hochschule Braunschweig (Direktor Prof. Dr.-Ing. O. Lutz) auf Anregung von Herrn Prof. Dr.-Ing. K. Gersten. Verfasser dankt den Herren Professoren Schlichting, Lutz und Gersten, die ihm die Durchführung dieser Arbeit ermöglichten. 相似文献
244.
Inclusion complexes between camphorquinone (CQ) and cyclodextrins (CDs) in deoxygenated aqueous solutions are shown to exhibit relatively strong room temperature phosphorescence (RTP). Among the various CDs tested, α-CD showed the strongest RTP signals. Interestingly, these signals differed significantly for the two enantiomers of CQ; the phosphorescence lifetime of (+)-CQ was about four times longer than that of (−)-CQ, being 352 ± 16 and 89 ± 6 μs, respectively. This enantiomeric selectivity is attributed to a difference in dissociation rates (competing with the radiative emission process) for the diastereoisomeric inclusion complexes dealt with, which have a 2:1 stoichiometry (α-CD:CQ:α-CD). Time-resolved RTP detection using different delay times enables the determination of the two enantiomers in a mixture without involving a separation technique. The minimum detectable fraction of (+)-CQ in a 2 mM sample was 13%. 相似文献
245.
Melián-Cabrera I Kapteijn F Moulijn JA 《Chemical communications (Cambridge, England)》2005,(21):2744-2746
Detemplation of zeolite beta has been successfully achieved at low temperature by controlled oxidation of the template using H2O2 and catalyzed by traces of Fe3+. With this approach, unlike calcination, the pristine structure of the material is well preserved; no extra-framework aluminium is formed. 相似文献
246.
Hans -Berndt Brinkmann 《manuscripta mathematica》1969,1(1):99-109
A category with O and biproducts for pairs carries a unique semiadditive structure. If furthermore identities have negatives, the category is additive. Using that Yoneda extensions over an abelian categoryA form a graded categoryÃ, we show that 0 and biproducts ofA retain their properties inÃ. Henceà is (graded) additive. We thus defined Baer addition of extensions which is furthermore unique. The aim of the paper is to dispense with all calculations which are usually involved in establishing the properties of Baer addition and to shorten the proof.Ich danke dem Forschungsinstitut für Mathematik der ETH in Zürich und dem Battelle Institut in Genf für Gastfreundschaft und Unterstützung. 相似文献
247.
P. Dörmer und W. Brinkmann 《Fresenius' Journal of Analytical Chemistry》1970,252(2-3):84-89
By means of micro-autoradiography incorporation studies of labelled compounds can be performed at the cellular level. The procedure described here aims at determining the amount of substances in terms of moles, incorporated into single cells.
14C is used as a label, since in contrast to tritium, the influence of -self-absorption of this isotope is negligible. Every autoradiograph is exposed together with a standard consisting of 14C-methacrylate. Hereby the relation of grain density to radioactivity in an autoradiograph is given. Grain counts are performed in an incident light microphotometer which makes use of the linear relationship between silver grain number and amount of light reflected by the grains. Therefore, measurements are performed in an integrating manner. The usual transmitted light is available for selecting the labelled cells for measurement.
Studie im Rahmen des Assoziationsvertrages EURATOM-GSF für Hämatologie Nr. 031641 BIAD. 相似文献
Studie im Rahmen des Assoziationsvertrages EURATOM-GSF für Hämatologie Nr. 031641 BIAD. 相似文献
248.
A new study of the luminescence emitted in the reactions Ca (4s3d 1D2) +HCl → CaCl(A, B) +H and Sr (5s4d 1D2, 5s5p 3P) + Cl2 → SrCl (A,B) + Cl has been performed under higher resolution. The investigation was performed comparatively, under bimolecular-encounter and colusion-relaxed conditions. We show the utility of this procedure for molecular spectroscopy and reaction kinetics. 相似文献
249.
250.
Alber T Bächler J Bartke J Bialkowska H Bloomer MA Bock R Braithwaite WJ Brinkmann D Brockmann R Buncic P Chan P Cramer PB Cramer JG Derado I Eckardt V Eschke J Favuzzi C Ferenc D Fleischmann B Foka P Freund P Fuchs M Gazdzicki M Gladysz E Harris JW Hoffman M Jacobs P Kabana S Kadija K Kosiec J Kowalski M Kühmichel A Lahanas M Lee JY Ljubicic A Margetis S Mitchell JT Morse RJ Nappi E Odyniec G Paic G Panagiotou AD Petridis A Piper A Posa F Poskanzer AM Pühlhofer F Rauch W Renfordt R Retyk W 《Physical review letters》1995,74(8):1303-1306