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981.
In this paper, we study the existence problem of axisymmetricthree-dimensional finger solutions of MullinsSekerkaequation. The finger solutions are travelling wave solutionswhose finger-shaped interfaces are moving along a certain directionat a constant speed within a cylindrical domain. The existenceof at least one axisymmetric three-dimensional finger solutionis obtained through a fixed-point argument of the Hilbert transformation. 相似文献
982.
983.
N. K. Dutta N. D. Tran N. R. Choudhury 《Journal of Polymer Science.Polymer Physics》2005,43(11):1392-1400
Scanning thermal microscopy (SThM) has been used for the visualization and characterization of an ultrathin plasma polymer film of perfluoro(methylcyclohexane) at a submicrometer level. The morphology, molecular dynamics, and lateral homogeneity of the ultrathin film have all been examined precisely with SThM. The growth of the plasma polymer film on a silicon wafer (Si‐wafer) has also been precisely determined using a new burning‐hole technique. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1392–1400, 2005 相似文献
984.
A series of phosphorescent cyclometalated iridium complexes with 2,5‐diphenylpyridine‐based ligands has been synthesized and characterized to investigate the effect of the simple ligand modification on photophysics, thermostability and electrochemistry. The complexes have the general structure (C∧N)2Ir(acac), where C∧N is a monoanionic cyclometalating ligand [e.g. 2,5‐diphenylpyridyl (dppy), 2,5‐di(4‐methoxyphenyl)pyridyl (dmoppy), 2,5‐di(4‐ethoxyphenyl)pyridyl (deoppy) and 2,5‐di(4‐ethylphenyl)pyridyl (deppy)]. The absorption, emission, cyclic voltammetry and thermostability of the complexes were systematically investigated. The (dppy)2Ir(acac) has been characterized using X‐ray crystallography. Calculation on the electronic ground state of (dppy)2Ir(acac) was carried out using B3LYP density functional theory. The highest occupied molecular orbital (HOMO) level is a mixture of Ir and ligand orbitals, while the lowest occupied molecular orbital (LUMO) is predominantly dppy ligand‐based. Electrochemical studies showed the oxidation potentials of (dmoppy)2Ir(acac), (deoppy)2Ir(acac), (deppy)2Ir(acac) were smaller than that of (ppy)2Ir(acac), while the oxidation potential of (dppy)2Ir(acac) was larger relative to (ppy)2Ir(acac). The 10% weight reduction temperatures of these complexes were above that of (ppy)2Ir(acac). All complexes exhibited intense green photoluminescence, which has been attributed to MLCT triplet emission. The maximum emission wavelengths in CH2Cl2 at room temperature were in the range 531–544 nm, which is more red‐shifted than that of (ppy)2Ir(acac). Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
985.
Tip-enhanced Raman spectroscopy in reflection mode makes possible the nanoscale characterization of non-transparent samples, such as silicon, inaccessible in transmission mode. However, a particular feature of this technique is the superposition of the far-field Raman signal with the near-field one generated in the tip vicinity sometimes resulting in a low near-field-to-far-field contrast. By using a polarized configuration and orientation optimization of a (0 0 1) crystalline Si sample we were able to enhance significantly the contrast through reducing the far-field contribution, reaching a value of about 40. This contrast enhancement method can be applied in principle to any crystalline sample. 相似文献
986.
987.
首次使用双狭缝相机对“神光”装置南路倍频线聚焦激光打靶所形成的线状等离子体均匀性进行了监测。由于实验条件的限制,相机的测量位置不太理想。为此,我们进行了修正,本文即是在修正基础上给出实验结果。修正后的结果表明,“神光”装置南路倍频线聚焦激光打靶部分发次所形成的线状等离子体均匀性不够理想。 相似文献
988.
We study a quasilinear elliptic equation in the unit ball ofℝ
m
. Using this result we get the existence of graphs with prescribed curvature on hyperbolic spacesℍ
m
inℍ
m
×ℝ. 相似文献
989.
The crystallization behavior, via annealing, of PEEK was investigated using FTIR spectroscopy. It was found that predominantly amorphous PEEK (e.g., quenched polymer) follows two distinct mechanisms when it is annealed. One is a lower energy relaxation process that involves the partial rotation of the ether linkages, allowing the molecular chains in the disordered phase to become better packed, and occurs from 50 to 140°C (slightly below Tg). This relaxation process is also observed by dynamic mechanical analyses. The other process is a crystallization that takes place above the glass transition, with its onset characterized by the rotation of the benzophenone linkages near Tg. Isothermal crystallization kinetics data on PEEK can be described by an Avrami equation with an Avrami constant n of about 1. 相似文献
990.
1,2-Diarylacetylenes have been synthesized by a facile method consisting of an addition of diaryl ketone with acetyl chloride and the elimination of resultant ethene chloride. Correlation between physical properties and structure of the 1,2-diarylacetylene has been studied by differential scanning calorimeter (DSC), refractor and electro-optical parameter test instrument. The results show that birefringence was increased with inserting cyclohexyl into the skeleton, but mesophase range, melting and clearing points were reduced with introducing the ethylene bridge in the molecule, and birefringence, viscosity, clearing point and mesophase range could all be decreased with perfluoro alkyl/alkoxyl terminal instead of alkyl/alkoxyl moiety. 相似文献