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51.
Michael S. Owens Madhu Vinjamur L.E. Scriven C.W. Macosko 《ournal of non Newtonian Fluid Mechanics》2011,166(19-20):1123-1128
Misting of liquids in forward roll coating is a problem under certain conditions. The relaxation time is known to influence misting but the fundamental mechanisms are not clear. A new mechanism for misting of dilute non-Newtonian liquids was proposed based on visualizations with a high-speed camera. With these liquids, filaments were created which sometimes transformed into beads-on-string structures and the beads were ejected as mist droplets when the structures broke. Misting was quantified by measuring sizes of the generated droplets, their count and mass concentration. The measurements were related to elasticity of the solutions through their relaxation times. Small levels of elasticity reduce the amount of misting, but higher levels lead to an increase. 相似文献
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Owens TM Nicholson KT Banaszak Holl MM Süzer S 《Journal of the American Chemical Society》2002,124(24):6800-6801
The formation of monolayers of alkylsilanes on a gold surface is characterized by X-ray photoelectron and reflection-absorption infrared spectroscopies. The reaction occurs through the activation of multiple Si-H bonds. Reactivity of the newly synthesized systems to oxygen and water is reported. 相似文献
55.
Our velocity measurements on quasi-two-dimensional turbulent flow in a rapidly rotating annulus yield self-similar (scale-independent) probability distribution functions for longitudinal velocity differences, deltav(l) = v(x+l)-v(x). These distribution functions are strongly non-Gaussian, suggesting that the coherent vortices play a significant role. The structure functions <[deltav(l)](p)> approximately l(zeta)p exhibit anomalous scaling: zeta(p) = p / 2 rather than the expected zeta(p) = p / 3. Correspondingly, the energy spectrum is described by E(k) approximately k(-2) rather than the expected E(k) approximately k(-5/3). 相似文献
56.
[reaction: see text] The Passerini reaction of N-protected amino aldehydes, isonitriles, and TFA using pyridine-type bases proceeds under mild conditions and directly affords alpha-hydroxy-beta-amino amide derivatives in moderate to high yields. These adducts are readily hydrolyzed to alpha-hydroxy-beta-amino carboxylic acids. Application of these key intermediates to concise syntheses of P(1)-alpha-ketoamide protease inhibitors is illustrated. 相似文献
57.
The differential cross section for the reaction 3He(γ,d)11H has been measured for proton energies 11–65 MeV. The results are compared with previous measurements and with a recent theoretical calculation. 相似文献
58.
J.F. Owens 《Physics letters. [Part B]》1978,76(1):85-88
The Q2 dependences of parton fragmentation functions are calculated using lowest-order quantum chromodynamics (QCD). The resulting scaling deviations have a simple intuitive form when a suitable valence-sea decomposition is employed for the quark fragmentation functions. 相似文献
59.
The vibrational excitation of HF and DF and the energy transfer efficiencies for various collision partners were investigated over the temperature and pressure ranges of 1400°K to 4100°K and 0.1 to 0.3 atm, respectively. The extent of excitation was determined as a function of time by continuously monitoring the infrared emission intensity at the center of the 1–0 vibration-rotation band of the molecule. Collisional efficiencies of HF, N2, O2, F, Cl, and DF in relaxing HF and of DF, HF, and N2 in relaxing DF are reported. A comparison with relaxation data for pure HF taken at lower temperature suggests that long-range attractive forces are mechanistically of major importance in the relaxation process. The relatively high efficiency of atomic chlorine in relaxing HF, i.e., (τP)HF–HF/(τP)HF–C1 ≥ 5 at 3000°K is discussed in terms of our previous result for atomic fluorine, i.e., (τP)HF–HF/(τP)HF–F = 18. 相似文献
60.
Aqueous reaction mixtures containing dihydroxyfumaric acid, M2+ (M = Zn, Co, Fe, and Mg) and acetate ion at room temperature give crystals, suitable for single-crystal X-ray diffraction studies, of composition [(MII)8(C4O7)4(H2O)12].24H2O, in which the C4O74- component is the alkoxide-tricarboxylate tetra-anionic species -OC(CO2-)3, a new oxyanion of carbon. All four compounds crystallize in the body-centered space group I3m with cell dimensions a approximately 15.0 A. Discrete electrically neutral [(MII)8(C4O7)4(H2O)12] molecules are present, with a cubane-like core consisting of four trigonal prismatic metal centers and four mu3-alkoxo bridges from separate -OC(CO2-)3 ligands. The octametallic molecule is highly symmetrical, with four fac tri-aqua octahedral metal centers tetrahedrally appended to the central cubane-based [(MII)8(C4O7)4 ]8- unit. The molecules assemble in the crystal in a body-centered cubic fashion, each being attached to its eight neighbors by 24 equivalent hydrogen bonds-an extreme example of self-complementarity. 相似文献