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141.
142.
T. Ramanathan S. Stankovich D. A. Dikin H. Liu H. Shen S. T. Nguyen L. C. Brinson 《Journal of Polymer Science.Polymer Physics》2007,45(15):2097-2112
Mechanical, thermal, and electrical properties of graphite/PMMA composites have been evaluated as functions of particle size and dispersion of the graphitic nanofiller components via the use of three different graphitic nanofillers: “as received graphite” (ARG), “expanded graphite,” (EG) and “graphite nanoplatelets” (GNPs) EG, a graphitic materials with much lower density than ARG, was prepared from ARG flakes via an acid intercalation and thermal expansion. Subsequent sonication of EG in a liquid yielded GNPs as thin stacks of graphitic platelets with thicknesses of ~10 nm. Solution‐based processing was used to prepare PMMA composites with these three fillers. Dynamic mechanical analysis, thermal analysis, and electrical impedance measurements were carried out on the resulting composites, demonstrating that reduced particle size, high surface area, and increased surface roughness can significantly alter the graphite/polymer interface and enhance the mechanical, thermal, and electrical properties of the polymer matrix. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2097–2112, 2007 相似文献
143.
Crosslinking behaviors of acrylonitrile butadiene rubber (NBR)/poly (vinyl chloride) (PVC) alloy, filled with anhydrous copper sulfate (CuSO4) particles, were investigated for the first time by dynamic mechanical analysis (DMA) under hetero and isothermal modes, respectively. In the heterothermal testing, (NBR/PVC)/CuSO4 compound showed two marked increases in the storage modulus (E′), corresponding to coordination crosslinking of NBR-CuSO4 and self-crosslinking of NBR and PVC respectively. During the isothermal testing, a dramatic increase in E′ was found at the initial stage while that of original NBR/PVC alloy was not detected. The marked increase in E′ of (NBR/PVC)/CuSO4 compound was mainly due to the crosslinking induced by coordination between CN and Cu2+. The increasing extent of E′ increased with the rise of CuSO4 content, suggesting the formation of a greater number of crosslinks. Moreover, the activation energy (Ea) of crosslinking process was about 139 kJ/mol. In this work, fourier transform infrared spectrum (FT-IR) and equilibrium swelling method were also performed for the characterization of the compound. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 41–51, 2007 相似文献
144.
145.
The spin coating method was used to assemble polymer (Poly (2,5-dibutoxy-1,4-phenylenevinylene)) (DBO-PPV) into the pores of porous alumina which was prepared by anodization. Four peaks in the photoluminescence (PL) spectra of the composite, with contributions from the DBO-PPV and porous alumina, were found. It was also found that the light emitting from the porous alumina could excite the photoluminescence of DBO-PPV. The nanometer effect of the porous alumina can lead to a blue shift of 90 nm of the PL peaks of DBO-PPV. 相似文献
146.
The present paper covers a salt of 2:18 heteropoly complex of tungstotitanophosphate prepared with the method of improved sequence preparation. The title compound was characterized by elemental analysis, 31P NMR spectra, polarography, cyclic voltammetry, IR, UV, X-ray powder diffraction , X-ray photoelectron spectra and TG-DTA analysis. The results show that the complex with the formula K8[TiP2W17O62]·12H2O has Dawson structure. Its properties such as spectra, redox behavior and thermal stability are discussed. 相似文献
147.
148.
For exponential weights, a necessary condition of weighted mean convergence for Lagrange interpolation is given. 相似文献
149.
Yi Lin 《Advances in Mathematics》2007,208(2):699-709
In this paper we construct six-dimensional compact non-Kähler Hamiltonian circle manifolds which satisfy the strong Lefschetz property themselves but nevertheless have a non-Lefschetz symplectic quotient. This provides the first known counterexamples to the question whether the strong Lefschetz property descends to the symplectic quotient. We also give examples of Hamiltonian strong Lefschetz circle manifolds which have a non-Lefschetz fixed point submanifold. In addition, we establish a sufficient and necessary condition for a finitely presentable group to be the fundamental group of a strong Lefschetz manifold. We then use it to show the existence of Lefschetz four-manifolds with non-Lefschetz finite covering spaces. 相似文献
150.
In this paper, we study the growth of solutions of a first order linear differential equation. From this we verify that a
conjecture given by Brück is true under the restriction of the hyper order less than 1/2, and obtain some uniqueness theorems
of a nonconstant entire function and its first derivative sharing a nonzero constant CM. The results in this paper also improve
some known results. Some examples show that the results in this paper are best possible.
Project supported by the NSFC (NO. A0324617) and the RFDP (NO. 20060422049).
Received: 20 April 2006 Revised: 4 February 2007 相似文献