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141.
Tomáš Mackuľak Miroslava Smolinská Petra Olejníková Josef Prousek Alžbeta Takáčová 《Chemical Papers》2012,66(2):156-160
The aim of this work was to evaluate the influence of ostazine dyes on the microbial population in environment. These dyes
act as photosensitizers after irradiation by visible light. The photodynamic effect was induced in this way. The effect of
irradiated water solutions of ostazine green, ostazine yellow, and ostazine blue on the Escherichia coli growth was tested. Furthermore, the effect of these dyes (at c = 3.5 μg mL−1) on bacterial growth was evaluated after their pretreatment by the Fenton reaction. Dramatic changes in dyes’ toxicity were
observed after coloured solutions were pretreated by the Fenton reaction. 相似文献
142.
Hansson PM Swerin A Schoelkopf J Gane PA Thormann E 《Langmuir : the ACS journal of surfaces and colloids》2012,28(21):8026-8034
Nanostructured particle coated surfaces, with hydrophobized particles arranged in close to hexagonal order and of specific diameters ranging from 30 nm up to 800 nm, were prepared by Langmuir-Blodgett deposition followed by silanization. These surfaces have been used to study interactions between hydrophobic surfaces and a hydrophobic probe using the AFM colloidal probe technique. The different particle coated surfaces exhibit similar water contact angles, independent of particle size, which facilitates studies of how the roughness length scale affects capillary forces (previously often referred to as "hydrophobic interactions") in aqueous solutions. For surfaces with smaller particles (diameter < 200 nm), an increase in roughness length scale is accompanied by a decrease in adhesion force and bubble rupture distance. It is suggested that this is caused by energy barriers that prevent the motion of the three-phase (vapor/liquid/solid) line over the surface features, which counteracts capillary growth. Some of the measured force curves display extremely long-range interaction behavior with rupture distances of several micrometers and capillary growth with an increase in volume during retraction. This is thought to be a consequence of nanobubbles resting on top of the surface features and an influx of air from the crevices between the particles on the surface. 相似文献
143.
Pavel Drabina Petr Funk Aleš Růžička Jiří Hanusek Miloš Sedlák 《Transition Metal Chemistry》2010,35(3):363-371
The optically pure 6-(4-alkyl-4,5-dihydro-1,3-oxazol-2-yl)pyridine-2-carboxylates have been prepared from 6-methoxycarbonylpyridine-2-carboxylic
acid by a sequence of three reactions with the overall yield of 40–50%. Some of these compounds form stable complexes with
Cu(II) ions in non-aqueous medium. Their polymeric structure was determined in the solid phase by X-ray diffraction analysis.
The Cu(II) complexes were also used as catalysts for addition reactions of terminal alkynes to imines giving substituted propargylamines
with maximum yield 64% and 37% ee. 相似文献
144.
145.
Agitating two immiscible liquids or a solid–liquid suspension is an operation frequently performed in the chemical and metallurgical industries, for example, in suspension/emulsion polymerization, heterogeneous/phase-transfer catalytic chemical reactions, and hydrometallurgical solvent extraction. For emulsification, suspension polymerization, solid particle dispersion, and crystallization, it is essential to be able to predict the mean drop/particle size and the drop/particle size distribution. A simple model was proposed for predicting the time evolution of drop size distribution during drop breaking, and was successfully tested on data published by Ruiz and Padilla (Hydrometallurgy 72:245–258, 2004) and by Sathyagal et al. (Chem Eng Sci 51: 1377–1391, 1996) and on our own data. The time evolution of DSD was investigated in a baffled tank agitated by a Rushton turbine for a liquid–liquid dispersion. The tests were carried out on a silicone oil–water dispersion (oil in water) with a dispersed-phase fraction of 0.00047. The drop sizes were determined by image analysis. 相似文献
146.
This paper considers computation of Fréchet and limiting normal cones to a finite union of polyhedra. To this aim, we introduce a new concept of normally admissible stratification which is convenient for calculations of such cones and provide its basic properties. We further derive formulas for the above mentioned cones and compare our approach to those already known in the literature. Finally, we apply this approach to a class of time dependent problems and provide an illustration on a special structure arising in delamination modeling. 相似文献
147.
M. Pavkov-Hrvojevi? M. Panti? S. Radoševi? M. Rutonjski M. Škrinjar D. Kapor 《Solid State Communications》2011,151(18):1205-1209
Bulk and surface magnetic excitations of the semi-infinite ferromagnetic semiconductor (FMS) superlattices and thin films described by Heisenberg and s-d model are analyzed using the transfer matrix method, developed in our previous work. Results are discussed in the narrow-band limit. The spin-wave frequencies for the semi-infinite narrow-band semiconductors are analyzed in both low- and high-frequency regions. Energies of localized excitations are compared to the bulk and the results of Green function formalism. Depending on the parameters of the system, the surface spin waves appear as “acoustical” and “optical”, and there are only some quantitative difference in the high-frequency region, comparing our method and the Green function method. In the framework of the same methodology, bulk and surface magnetic excitations of more complicated superlattices and thin films made of the FMS superlattices are analyzed in terms of dependence of the system parameters. It is shown that the s-d interaction governs the behavior of the systems. Dependence on bulk and surface parameters is discussed. 相似文献
148.
Tomáš Gbur Václav Čuba Viliam Múčka Martin Nikl Karel Knížek Milan Pospíšil Ivo Jakubec 《Journal of nanoparticle research》2011,13(10):4529-4537
Preparation of zinc oxide nanoparticles from aqueous solutions containing zinc nitrate or formate using UV irradiation was
investigated. Analysis of solid phase formed during irradiation confirmed the presence of zinc oxide or zinc peroxide nanoparticles
ranging in size from 1 to 70 nm, depending on initial precursors. Annealing at temperatures 650–1000 °C results in forming
of rice-like zinc oxide particles, up to hundreds of nm in size. Photochemical method yields material with high chemical purity
and uniform particle size distribution. In addition, photo-induced doping of zinc oxide with lanthanum was studied. Presence
of lanthanum in zinc oxide crystal lattice and post-preparation treatment in reduction atmosphere significantly increase the
UV excitonic luminescence at 395 nm in radioluminescence spectra. 相似文献
149.
T. Agne M. Deicher V. Koteski H.-E. Mahnke H. Wolf T. Wichert 《Hyperfine Interactions》2004,159(1-4):55-61
The structural properties of the nanocrystalline semiconductor ZnO (nano-ZnO) doped with the donor Indium were investigated
by perturbed γγ angular correlation spectroscopy (PAC) and extended X-ray absorption fine structure measurements (EXAFS).
Up to an average concentration of one In atom per nanocrystallite, PAC measurements show that about 12% of the 111In atoms are incorporated on substitutional Zn sites. At higher In concentrations, new In defect complexes are visible in
the PAC spectra, which dominate the spectra if the average In concentration exceeds one In atoms per nanocrystallite. In addition,
the local environment of Zn and In atoms in In doped nano-ZnO was investigated by EXAFS. The measurements at the K edge of
Zn show that the crystal structure of nano-ZnO corresponds to bulk ZnO. In heavily In doped nano-ZnO the EXAFS experiments
at the K edge of In exhibit an expansion of the first O shell about the In site. Since about four O atoms are detected in
this first shell a substitutional incorporation of the In atoms in the ZnO lattice is suggested. The second shell to be occupied
by Zn atoms as well as higher shells are almost invisible, which might have the same microscopic origin as the occurrence
of defect complexes observed by PAC. 相似文献
150.