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1.
2.
Marcelo Do Amaral Steven Van Es Jos M. Asua 《Journal of polymer science. Part A, Polymer chemistry》2004,42(16):3936-3946
The production of high‐solid‐content, low‐viscosity latexes is an active field in both industry and academia. The viscosity of polymer dispersions has a clear dependence on the particle size distribution (PSD). An example is the rule of thumb that a bimodal PSD enables the reduction of the viscosity with respect to monomodal systems. Despite important progress in theoretical work, not much has been done to quantitatively predict the low shear viscosity of aqueous polymer dispersions as a function of the complex PSD. In this work, the capability of a low‐shear‐viscosity equation to quantitatively account for the influence of both the PSD and the physicochemical characteristics of the dispersions is experimentally assessed. An analysis, consistent with theoretical concepts, of the data with semiempirical correlations is proposed. Next, with values of the parameters of the viscosity equation obtained experimentally, the effect of a latex with a 70% solid content on the low shear viscosity is examined. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3936–3946, 2004 相似文献
3.
We study the phase transitions to the Higgs phase of the finite temperature 2+1 dimensional Abelian Higgs model in terms of Ginzburg-Landau vortices. We find that vorticity is a good order parameter which allows us to determine the order of the transitions. 相似文献
4.
Magnetization measurements in the (Dy
x
Y1−x
)Fe2 intermetallic compounds show evidence of blocking of domain wall motion. This effect is a function of concentrationx. The direction of magnetization is also dependent on the Dy concentration. We have used the Mossbauer spectroscopy of57Fe to verify the direction of magnetization in the series as a function ofx and temperature. The results show that this change in easy direction occurs at higher temperatures than those where the blocking
is detected through DC magnetization measurements.
supported by RHAE/SCT. 相似文献
5.
M. Alves Da Silva M. Helena Gil A. P. Piedade J. S. Redinha A. M. Oliveira Brett J. M. Caridade Costa 《Journal of polymer science. Part A, Polymer chemistry》1991,29(2):269-274
The immobilization of catalase on grafted membranes of poly(ethylene)-g-co-acrylic acid and poly(tetrafluoroethylene)-g-co-acrylic acid and their application in hydrogen peroxide electrochemical sensors is described. The introduction of carboxylic acid groups onto a hydrophobic support provides a good environment for subsequent enzyme immobilization. This single membrane, hydrogen peroxide sensor showed significant improvement with respect to the double membrane versions. The response is very rapid, the linear range being from 10 μM up to 6 mM, with a detection limit of 4.7 μM, and a lifetime of more than 4 months. 相似文献
6.
The TG and DTA curves and diffractograms of powdered CeO2 samples irradiated with a CO2 laser beam with powers of 0.41–1.39 kW/cm2 are presented. The laser treatment induced structural changes and probably generation of a metastable phase. X-ray diffraction coupled with thermal analysis was used to establish the structural modifications in the irradiated samples after heating. 相似文献
7.
Scaling impacted structures 总被引:1,自引:0,他引:1
Summary The problem of non-scalability of structures under impact loads caused by strain-rate effects is solved in this article by properly correcting the impact velocity. The technique relies on the use of an alternative dimensionless basis, together with a mathematical model which allows the calculation of a correction factor for the impact velocity. This new velocity, when applied to the model, makes it to assure the satisfaction of the scaling laws. The indirect similitude method detailed here is applied to two strain-rate sensitive structures, a double plate under in-plane impact and a beam subjected to a blast load. The results show a very good agreement so that the model and a prototype made from strain rate sensitive materials behave the same.accepted for publication 3 March 2004 相似文献
8.
Supported by a Heisenberg-scholarship of the DFG 相似文献
9.
A.C. Marques R.M. Almeida A.R. Ramos E. Alves 《Journal of Sol-Gel Science and Technology》2004,32(1-3):287-291
Photosensitive organic-titania hybrid materials have been prepared from metal alkoxides and various organic ester compounds with
double bonds. The refractive index of the film increases with the decrease of the concentration of the organic ester compound, and the highest refractive index of 1.62 is obtained when 2-hydroxymethyl acrylate (HOA) is used as the organic ester and the molar ratio of HOA to Ti is 0.5. The material with the highest refractive index is exposed to femtosecond pulse using the multi-beam laser interference technique. After laser irradiation, the irradiated parts of the material are photopolymerized and periodic structures can be obtained by development of the unirradiated parts. In the case of laser irradiation of 120 J total energy for 5 min, the periodic structure obtained corresponds to 2D photonic crystal structure which is composed of two parts; the material with the highest refractive index and the air. 相似文献
10.
Alves Lourdes A. Felipe Maria G. A. Silva JoÃo B. Almeida E. Silva Silvio S. Prata Arnaldo M. R. 《Applied biochemistry and biotechnology》1998,70(1):89-98
Applied Biochemistry and Biotechnology - In order to remove or reduce the concentrations of toxic substances present in the sugarcane bagasse hemicellulose hydrolysate for xyloseto-xylitol... 相似文献