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61.
Simona Lai Emanuela Locci Giuseppe Saba Ivan Husu Giancarlo Masci Vittorio Crescenzi Adolfo Lai 《Journal of polymer science. Part A, Polymer chemistry》2003,41(20):3123-3131
Dry and hydrated poly(vinyl alcohol) (PVA) gels with 55% (a‐PVA) and 61% (s‐PVA) syndiotacticity and related PVA/lactyl chitosan (LC) blends have been investigated with 129Xe and cross‐polarization/magic‐angle‐spinning 13C NMR techniques. Although the dry gels exhibit two broad 129Xe resonances in the slow‐to‐intermediate exchange limit, both hydrated gels show three resonances. The corresponding dry blends exhibit two signals, the chemical shifts and line widths of which change with respect to those of pure PVA, whereas one (a‐PVA/LC) or two (s‐PVA/LC) signals appear in the spectra of the hydrated blends. A comparative analysis of the data demonstrates that LC rearranges the domains of the polymeric matrix in both the dry and hydrated blends according to the syndiotacticity of the PVA chains. Information on the molecular motions of the amorphous and swollen polymeric domains in the kilohertz range has been obtained from an analysis of the spin‐lattice relaxation times. These data indicate that the dynamics and arrangement of the PVA chains in the gels are strongly affected by their tacticity and the addition of the copolymer LC. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3123–3131, 2003 相似文献
62.
M. Abid Ali P. J. Hickman A. T. Clementson 《The Journal of the Operational Research Society》1975,26(2):243-252
Automatic Interaction Detection (AID) is a multivariate statistical technique. This paper describes the algorithm and illustrates its application to a particular case study in the British fishing industry. 相似文献
63.
Kazimierz Sykut Jadwiga Saba Barbara Marczewska Grażyna Dalmata 《Journal of Electroanalytical Chemistry》1984,178(2):295-303
The mechanism of the cap-pair effect was examined with respect to its acceleration of the electro-reduction of Zn2+ ions in NaCIO4, NaCl and NaBr. It was found that the presence of thiourea in the solution increased the rate of the electrode process; a role is played in the acceleration by the composition of zinc complexes formed in the bulk of the solution. 相似文献
64.
65.
The results obtained in the acetolysis of α - chloro - ketones 1a-e are compared with those previously reported for the acetolysis of the corresponding α' - phenylthio-α - chloro - ketones 15a-e and discussed in terms of the enolization-solvolysis mechanisms (Schemes 1 and 2). 相似文献
66.
Muhammad Akram Saba Siddique Bijan Davvaz 《Journal of Applied Mathematics and Computing》2018,57(1-2):279-302
A neutrosophic set is a generalization of an intuitionistic fuzzy set. Neutrosophic models give more flexibility, precisions and compatibility to the system as compared to intuitionistic fuzzy models. In this research study, we apply the concept of neutrosophic sets to graphs and discuss certain concepts of single-valued neutrosophic graphs. We illustrate the concepts by several examples. We investigate some interesting properties. We describe an application of single-valued neutrosophic graph in decision making process. We also present the procedure of our proposed method as an algorithm. 相似文献
67.
Saba Fatema Mohammad Hassan Murad 《International Journal of Theoretical Physics》2013,52(7):2508-2529
This paper presents a family of two-parametric interior solutions of Einstein–Maxwell field equations in general relativity for a static spherically symmetric distribution of a charged perfect fluid with particular choice of charge distribution and the metric component g 00. This family gives us wide range of parameters, n and K, for which the solutions are regular and acceptable on physical grounds and hence suitable for modeling of charged compact star. The maximum allowable mass and corresponding radius, for this family of solutions with the particular form of charge distribution, is determined to be 2.48M ⊙ and 10.56 km respectively by assuming the stellar “surface” density equal to strange (quark) matter density at zero pressure. It is hoped that our investigation may be of some importance in connection with the study of internal structure of electrically charged strange (quark) star. 相似文献
68.
Mohammad Hassan Murad Saba Fatema 《International Journal of Theoretical Physics》2013,52(12):4342-4359
In continuation of recent work done by the present authors (Int. J. Theor. Phys. 2013, doi:10.1007/s10773-013-1538-y, hereafter paper I) some new exact families of static spherically symmetric perfect fluid solution of Einstein–Maxwell gravitational field equations are presented. These solutions and the corresponding equations of state, presented in parametric form, may be astrophysically significant in constructing relativistic stellar models of electrically charged self-bound stars. 相似文献
69.
A highly efficient one‐pot three‐component reaction of aldehydes or ketones, amines, and trimethyl or triethyl phosphite catalyzed by p‐dodecylbenzensulfonic acid is developed for the synthesis of α‐aminophosphonates at room temperature in water. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:174–178, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21079 相似文献
70.
The application of the fast gradient method to the dual quadratic programming (QP) problem leads to the dual fast projected gradient (DFPG) method. The DFPG converges with O(k ?2) rate, where k > 0 is the number of steps. At each step, it requires O(nm) operations. Therefore for a given ${\varepsilon > 0}$ an ${\varepsilon}$ -approximation to the optimal dual function value one achieves in ${O(nm\varepsilon^{-\frac{1}{2}})}$ operations. We present numerical results which strongly corroborate the theory. In particular, we demonstrate high efficiency of the DFPG for large scale QP. 相似文献