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131.
Carmen Racles Viorica Gaina Mihai Marcu Maria Cazacu Mihaela Simionescu 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(9):1605-1617
Abstract Organofunctional siloxane oligomers containing maleimide were synthesized by condensation reaction of α. ω-hydroxypropylsiloxane oligomers with n-[4-(chlorocarbonyl)phenyl]maleimide. A model compound [bis(maleimide-ester)disiloxane] was obtained to facilitate the characerization of the oligomers. Then, the heterogeneous catalyzed ring-opening cationic polymerization technique was applied to obtain an oligomer starting from the model compound and octamethylcyclotetrasiloxane. The structures of the resulting oligomers were confirmed by elemental analysis, IR and 1H-NMR spectroscopy. They were characterized by determining softening points, solubility and studying their thermal behavior by thermogravimetric (TGA and differential scanning calorimetry (DSC) measurements. 相似文献
132.
Ecaterina Stela Dragan Marcela Mihai Simona Schwarz 《Colloids and surfaces. A, Physicochemical and engineering aspects》2006,290(1-3):213-221
Three ionic/nonionic random copolymers of sodium 2-acrylamido-2-methylpropanesulfonate (AMPS) with either t-butyl acrylamide (TBA) or methyl methacrylate (MM), were used in the preparation of some polyelectrolyte complex dispersions (PCD) with two strong polycations of integral type, poly(diallyldimethylammonium chloride) (PDADMAC), and an ionene type polycation, containing 95 mol% N,N-dimethyl-2-hydroxypropyleneammonium chloride repeat units (PCA5). The novelty of the paper is that PCDs with a high colloidal stability, both before and after the complex stoichiometry, were obtained even with hydrophilic/hydrophobic polyanions, with a high titrant addition rate (TAR), a less explored parameter, which allows a fine control of PCDs aggregation level, in salt-free aqueous solutions. The characteristics of PCDs were also correlated with the polyanion average charge density and the structure of the nonionic comonomer, at a constant TAR, the polyanion with the lowest charge density leading to the highest turbidities and the lowest colloidal stabilities. A mechanism of the PCDs colloidal stabilization as a function of TAR was suggested in the paper. 相似文献
133.
The fundamental parameter (FP) method was extended to account for the geometrical details of experimental x‐ray fluorescence (XRF) detection. In the traditional FP method the primary fluorescence photons have parallel pathways towards the detector. In the new approach the primary fluorescence photons can travel in any direction which allows them to reach the detector if not absorbed or scattered. The derived XRF signal equation explicitly depends on the length of the collimator in front of the detector, the detector size, position and orientation. An algorithm which numerically calculates the XRF signal for any set of parameters was developed and implemented for the Kα XRF signal of arsenic in skin. Optimal positions and orientations of the detector and collimator ensemble which maximize the XRF signal were found. Results and limitations of the method were also discussed. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
134.
Kinetic behaviors of niobium and titanium carbide precipitates in iron are simulated with cluster dynamics.The simulations,carried out in austenite and ferrite for niobium carbides,and in austenite for titanium carbide,are analyzed for dependences on temperature,solute concentration,and initial cluster distribution.The results are presented for different temperatures and solute concentrations,compared to experimental data available.They show little impact of initial cluster distribution beyond a certain relaxation time and that highly dilute alloys with monomers only present a significantly different behavior from denser alloys or ones with different initial cluster distributions. 相似文献
135.
136.
Sebastiano Guerra Julien Iehl Michel Holler Mihai Peterca Daniela A. Wilson Benjamin E. Partridge Shaodong Zhang Robert Deschenaux Jean-Fran?ois Nierengarten Virgil Percec 《Chemical science》2015,6(6):3393-3401
Twelve chiral and achiral self-assembling dendrons have been grafted onto a [60]fullerene hexa-adduct core by copper-catalyzed alkyne azide “click” cycloaddition. The structure adopted by these compounds was determined by the self-assembling peripheral dendrons. These twelve dendrons mediate the self-organisation of the dendronized [60]fullerene into a disc-shaped structure containing the [60]fullerene in the centre. The fullerene-containing discs self-organise into helical supramolecular columns with a fullerene nanowire-like core, forming a 2D columnar hexagonal periodic array. These unprecedented supramolecular structures and their assemblies are expected to provide new developments in chiral complex molecular systems and their application to organic electronics and solar cells. 相似文献
137.
138.
We prove an extension theorem for effective purely log-terminal pairs (X, S + B) of non-negative Kodaira dimension ${\kappa (K_X+S+B)\ge 0}$ . The main new ingredient is a refinement of the Ohsawa–Takegoshi L 2 extension theorem involving singular Hermitian metrics. 相似文献
139.
In this paper the operator-valued martingale transform inequalities in rearrangement invariant function spaces are proved. Some well-known results are generalized and unified. Applications are given to classical operators such as the maximal operator and the p-variation operator of vector-valued martingales, then we can very easily obtain some new vector-valued martingale inequalities in rearrangement invariant function spaces. These inequalities are closely related to both the geometrical properties of the underlying Banach spaces and the Boyd indices of the rearrangement invariant function spaces. Finally we give an equivalent characterization of UMD Banach lattices, and also prove the Fefferman-Stein theorem in the rearrangement invariant function spaces setting. 相似文献
140.
From J-action point of views, slant surfaces are the simplest and the most natural surfaces of a (Lorentzian) Kähler surface (\(\tilde M,\tilde g\), J). Slant surfaces arise naturally and play some important roles in the studies of surfaces of Kähler surfaces (see, for instance, [13]). In this article, we classify quasi-minimal slant surfaces in the Lorentzian complex plane C 1 2 . More precisely, we prove that there exist five large families of quasi-minimal proper slant surfaces in C 1 2 . Conversely, quasi-minimal slant surfaces in C 1 2 are either Lagrangian or locally obtained from one of the five families. Moreover, we prove that quasi-minimal slant surfaces in a non-flat Lorentzian complex space form are Lagrangian. 相似文献