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31.
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
32.
Andr Luciani Christopher J. G. Plummer Tuan Nguyen Lszl Garamszegi Jan‐Anders E. Mnson 《Journal of Polymer Science.Polymer Physics》2004,42(7):1218-1225
The effects of the size (pseudo‐generation number) and nature of end groups on physical and rheological properties were investigated for a series of hyperbranched polyesters based on an ethoxylated pentaerythritol core and 2,2‐bis‐(hydroxymethyl)propionic acid repeat units. The observed linear dependence of the melt viscosity on the molar mass in the high pseudo‐generation‐number limit indicated that entanglement effects were substantially absent. Moreover, the marked influence of end capping of the end groups on the physical and rheological properties suggested that intermolecular interactions were dominated by contacts between the outer shells of the molecules, in which the end groups were assumed to be concentrated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1218–1225, 2004 相似文献
33.
Simplicial complexes X provide commutative rings A(X) via the Stanley- Reisner construction. We calculated the cotangent cohomology, i.e., T1 and T2 of A(X) in terms of X. These modules provide information about the deformation theory of the algebro geometric objects assigned to X. 相似文献
34.
35.
Mari Grobbelaar‐Van Dalsen 《Mathematical Methods in the Applied Sciences》2004,27(11):1301-1315
This paper is concerned with well‐posedness results for a mathematical model for the transversal vibrations of a two‐dimensional hybrid elastic structure consisting of a rectangular Reissner–Mindlin plate with a Timoshenko beam attached to its free edge. The model incorporates linear dynamic feedback controls along the interface between the plate and the beam. Classical semigroup methods are employed to show the unique solvability of the coupled initial‐boundary‐value problem. We also show that the energy associated with the system exhibits the property of strong stability. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
36.
37.
Some boundedness properties for an extension operator are proved and used together with techniques of Maly [24], Meyers [29],
Fonseca and Müller [13] and Fonseca and Marcellini [12] to obtain lower semicontinuity results in BV for quasiconvex integrals of super-linear growth.
Received January 25, 1997 / Accepted October 3, 1997 相似文献
38.
We consider an optimal growth (multi-sector) model with nonconvex technology. Using the Clarke results on generalized gradients, we prove that the value function has left and right derivatives with respect to the initial capital stock, without requiring supermodularity assumptions. 相似文献
39.
Jan Cieliski 《Chaos, solitons, and fractals》1995,5(12):2303-2313
An effective algorithm to construct the Darboux matrix based on the dressing method is proposed. Our approach consists in representing the linear problem as a system of algebraic constraints on two matrices. The Darboux matrix is determined from the requirement that the Darboux-Bäcklund transformation preserves these constraints. A non-isospectral deformation of the derivative nonlinear Schrödinger equation is discussed as an example. 相似文献
40.