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81.
82.
The authors study the bifurcation problems of rough heteroclinic loop connecting three saddle points for the case β1 > 1, β2 > 1, β3 < 1 and β1β2β3 < 1. The existence, number, coexistence and incoexistence of 2-point-loop, 1-homoclinic orbit and 1-periodic orbit are studied. Meanwhile, the bifurcation surfaces and existence regions are given. 相似文献
83.
The compression behaviour of Ni77P23 amorphous alloy is investigated at room temperature in a diamond-anvil cell instrument using in-situ high pressure energy dispersive x-ray diffraction with a synchrotron radiation source. The equation of state is determined by fitting the experimental data according to the Birch-Murnaghan equation. It is found that the structure of Ni77P23 amorphous alloy is stable under pressures up to 30.5 GPa. Within the pressure range from zero to the experimental one, the pressure-induced structural relaxation is reversible. 相似文献
84.
85.
86.
Since its discovery in 1946, NMR has become a valuable tool in physics, chemistry, biology, and medicine. With the invention of NMR logging tools that take the medical MRI or laboratory NMR equipment and turn it inside-out, the application of sophisticated laboratory techniques to determine formation properties in situ is now available. The capability has opened a new era in formation evaluation just as the introduction of NMR has revolutionized the other scientific areas. 相似文献
87.
88.
With different amounts of KCl added in the PNBA(p- nitro benzoic acid) aqueous solution, the factors affecting the SERS (Surface Enhanced Raman Scattering) are studied systematically on the surface of Copper. The results show that in PNBA aqueous solution the occurrence of SERS effect stongly depends on the existence of Cl-. The amount of KCl added affects not only the emergence and the intensity of SERS effect, but also the adsorption properties such as the adsorption manner,etc. 相似文献
89.
以噻吩为单体,在等离子体环境中聚合成致密的有机膜。利用Rutherford背散射(RB2S)和质子弹性反冲(ERD)、傅里叶红外谱(FTIR)测定了膜的成分和结构;从近红外-可见-紫外光的反射和透射谱,运用传递矩阵方法研究了膜的光学性质;此外,还探讨了24keV的I+离子束的注入对等离子体噻吩聚合膜的掺杂效应。结果表明,注入层内电荷载流子的输运机理可用Mott的可变自由程跳跃(VRH)理论给以解释。
关键词: 相似文献
90.
Jing Zhang Dan Shan Shaolin Mu 《Journal of polymer science. Part A, Polymer chemistry》2007,45(23):5573-5582
A copolymer, poly(aniline‐co‐o‐aminophenol), was prepared chemically by using ammonium peroxydisulfate as an oxidant. The monomer concentration ratio of o‐aminophenol to aniline strongly influences the copolymerization rate and properties of the copolymer. The optimum composition of a mixture for the chemical copolymerization consisted of 0.3 M aniline, 0.021 M o‐aminophenol, 0.42 M ammonium peroxydisulfate, and 2 M H2SO4. The result of cyclic voltammograms in a potential region of ?0.20 to 0.80 V (vs.SCE) indicates that the electrochemical activity of the copolymer prepared under the optimum condition is similar to that of polyaniline in more acid solutions. However, the copolymer still holds the good electrochemical activity until pH 11.0. Therefore, the pH dependence of the electrochemical property of the copolymer is improved, compared with poly(aniline‐co‐o‐aminophenol) prepared electrochemically, and is much better than that of polyaniline. The spectra of IR and 1H NMR confirm that o‐aminophenol units are included in the copolymer chain, which play a key role in extending the usable pH region of the copolymer. The visible spectra of the copolymers show that a high concentration ratio of o‐aminophenol to aniline in a mixture inhibits the chain growth. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5573–5582, 2007 相似文献