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91.
The results of an experimental investigation of the structure of the flow separated from the model of a straight wing with point sources of disturbances (bulges) made on its surface are presented. The variations in the three-dimensional flow pattern are analyzed as functions of the bulge shapes and positions. It is found that the flow can be controlled by means of mounting the bulges downstream of the separation line, in the return flow region, since in this case they hinder large-scale vortex formation in the separation zone. The results obtained show that there is an intimate connection between the vortices and the separation zone as a whole. Impeding the vortex structure formation can result in considerable variations in the separation zone structure, up to its complete disappearance. 相似文献
92.
Luiza P. V. Calsavara Gisella M. Zanin Flavio F. de Moraes 《Journal of inclusion phenomena and macrocyclic chemistry》2012,73(1-4):219-224
Inclusion complexes using α-, β-, γ-, and hydroxypropyl-β-CD (HP-β-CD) were produced with the antibiotic enrofloxacin, with the aim of increasing its solubility by complexation. Phase solubility diagrams were obtained, to confirm the formation of inclusion complexes, and to determine the solubility enhancement and stability constant of each complex. Enrofloxacin inclusion in β-CD showed the highest value of the complex stability constant (35.56?mmol?L?1), but the greatest increase in solubility was obtained using HP-β-CD reaching a 1258% increase over enrofloxacin solubility in the absence of CD. The order of highest enrofloxacin solubility achieved was: HP-β-CD?>?α-CD?>?γ-CD?>?β-CD. In addition, formation of complexes was confirmed by differential scanning calorimetry and thermogravimetry, applied to the complexes obtained by the kneading technique. The influence of citric acid, alone or as an adjunct of β-CD, on the solubility of enrofloxacin was also determined. A solution of 15?mmol?L?1 citric acid dissolved 10?g?L?1 of enrofloxacin, but a gradual increase in β-CD concentration in the presence of citric acid did not increase the degree of solubilization of enrofloxacin. 相似文献
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95.
A. P. Brylyakov G. M. Zharkova B. Yu. Zanin V. N. Kovrizhina D. S. Sboev 《Journal of Applied Mechanics and Technical Physics》2003,44(5):648-653
Results for a turbulized flow past the windward side of a swept wing model are presented. Origination of steady disturbances in the form of streamwise structures is found. The greatest effect on the formation of these disturbances is exerted by the curvature of the external flow streamlines. The secondary flow in the boundary layer leads to an increase in the characteristic scale of disturbances in the transverse direction, as compared to the flow around the model at a zero yaw angle. 相似文献
96.
José H. B. De Araújo Flávio F. de Moraes Gisella M. Zanin 《Applied biochemistry and biotechnology》1999,79(1-3):713-722
The perform ance of commercial xylanases in totally chlorine-free bleaching of kraft pulp from conifer was tested with Pulpzyme
HC (Novo Nordisk) and Cartazyme NS-10 (Sandoz/Clariant), at 500 U/kg of dry pulp, respectively. The treatment with Pulpzyme
(Xp) or Cartazyme (Xc) has been combined with stages of bleaching using: oxygen (O), sulfuric acid (A), and extraction with hydrogen peroxide (Eop). The following sequences have been tested: OXpAEop, OXcAEop, XpOAEop, XcOAEop and OAEop, Kraft pulp bleached at the Klabin industrial plant using the sequence, CEH (chlorine, alkaline extreaction, and hypochlorination)
was, used for comparison. The following average values were obtained: 1. Kappa number: OXpAEop, 4.8; OXcAEop, 4.9; XpOAEop, 5.0; XcOAEop, 4.9; OAEop, 5.6, and CEH, 1.9; 2. Brightness (% ISO values): OXpAEop, 68.4; OXcAEop, 70.1; XpOAEop, 67.9; XcOAEop, 26.9; XpOAEop, 23.4; XcOAEop, 23.1; OAEop, 25.4, and CEH, 25.2. Pulps that were treated with xylanases, before or affer the delignification with oxygen, have shown
reduced kappa number and higher brightness than the pulp OAEop, Enzyme treatment before delignification with oxygen reduces pulp viscosity. Brightness obtained for pulp produced with bleaching
sequences containing the enzymatic treatment, when compared with the control, CEH, shows that the xylanases enhance the action
of the bleaching agents. 相似文献
97.
Alcohol ethoxylates (AEs) are nonionic surfactants. They are industrially important compounds that have historically been difficult to analyze, with the best results to date achieved through derivatization (e.g., silylation) followed by analysis by gas chromatography/mass spectrometry (GC/MS). Recently, mass spectrometric techniques such as field desorption (FD), time-of-flight secondary ion mass spectrometry (TOF-SIMS), fast atom bombardment (FAB), electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) have been employed to analyze surfynol(R) 4xx. In an effort to produce low-cost alkyl-capped AEs and anionic detergents from AEs, a fast and reliable measure of the product yields and conversions from AEs is required in research. We found that the product yields and conversions from reactions of AEs, obtained by the employment of atmospheric pressure chemical ionization (APCI), were in good agreement with those obtained from proton nuclear magnetic resonance spectroscopy ((1)H-NMR). Therefore, APCI can be used as a validated tool for studying AE reactions. Mixtures that contain either silylated or unsilylated ethoxylates and/or carboxylates yield the same APCI mass spectra. Copyright -Copyright 1999 John Wiley & Sons, Ltd. 相似文献
98.
O. M. Golitsyna S. N. Drozhdin A. E. Gridnev V. V. Chernyshev I. E. Zanin 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(9):1291-1294
The dielectric properties of composite structures based on porous aluminum with inclusions of triglycine sulphate and Rochelle
salt were investigated. The effect of structured and adsorbed water on the dielectric behavior of the nanocomposite under
study was found. 相似文献
99.
S. V. Stovbun A. A. Skoblin A. M. Zanin Ya. A. Litvin V. A. Tverdislov A. A. Kirsankin M. V. Grishin B. R. Shub 《Russian Journal of Physical Chemistry B, Focus on Physics》2014,8(5):620-625
The initiation of the formation of strings in low-concentration chiral solutions was experimentally studied. The domains of initiation were classified according to dimensions: (0–3)D. The dipole-dipole mechanism of the formation of anisotropic nucleation in a mesophase was considered. The role of dispersion interactions in the assembly of supramolecular stacks was estimated at ~0.3–0.4 eV. The threshold values of string formation in chiral mixtures were determined. A phenomenon of the formation of paired strings was established and characterized. 相似文献
100.
I.M. Barkalov V.I. Goldanskii D.P. Ktryukhin A.M. Zanin 《Chemical physics letters》1980,73(2):273-277
The rate of chain hydrobromination of ethylene has been determined for ordinary and deuterated compounds between 90 and 40 K and was found to reach a plateau value below ≈70 K. The rate-determining step in the development of chains at low temperatures appears to be the formation of the intermediate radical ?2H4Br rather than its subsequent transformation into ethyl bromide via the transfer of hydrogen atoms. 相似文献