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71.
Fumiyoshi Ikkai Mitsuhiro Shibayama Shunji Nomura Charles C. Han 《Journal of Polymer Science.Polymer Physics》1996,34(5):939-945
Mesoscopic structures of poly(vinyl alcohol)(SINGLEBOND)Congo red (PVA(SINGLEBOND) CR) complexes in aqueous solutions were investigated in terms of dynamic light scattering (DLS) technique. The intensity-intensity time correlation function, g(2)(t), was analyzed with an equation including a single and a stretched exponential function. Two diffusion coefficients, Df (fast) and Ds (slow) were evaluated. Df was converted to the apparent correlation length, ξapp, via the mode-mode coupling hypothesis. The estimated ξapp was insensitive to the sol(SINGLEBOND)to(SINGLEBOND)gel transition but decreased with CR concentration. This change may be related to the electrostatic screening effect. On the other hand, Ds oscillates with increasing CR concentration at a specific PVA concentration range. This explains well the reentrant sol(SINGLEBOND)gel(SINGLEBOND)sol(SINGLEBOND)gel transition behavior observed in the PVA(SINGLEBOND)CR systems. Ds seems to represent the mobility of the PVA(SINGLEBOND)CR complexes, which annihilates at the gel point. © 1996 John Wiley & Sons, Inc. 相似文献
72.
Masaru Yoshida Masaharu Asano Hideki Omichi Masaharu Miyajima Yasuo Takahashi Hidetoshi Yamanaka Noriyuki Yonezawa Ryoichi Katakai 《Macromolecular theory and simulations》1993,2(3):377-384
The loosely cross-linked poly(acryloyl-L -proline methyl ester) gel, which is known as one of the typical thermo-responsive gels, shows a volume transition around approximately 14°C in pure water. This volume transition is shifted to higher temperature by treatment in aqueous sodium dodecyl sulfate (SDS). The analysis of the swelling-temperature curve (frequency distribution) was performed according to a moment analysis, in which the area under the swelling-temperature curve (AUC), mean swelling transition temperature (MSTT) and variance of swelling transition temperature (VSTT) were calculated. It is shown that the apparent volume transition temperature can be estimated from MSTT and that VSTT can be used to characterize the shape of the corresponding curves. 相似文献
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Secondary 2-thiophenecarboxamides efficiently undergo unique triarylation accompanied by formal decarbamoylation under palladium catalysis. 3-Substituted thiophenes, especially having an electron-withdrawing group, can also be triarylated. 相似文献
78.
We study the size dependence of the nonlinear response of weakly confined excitons for the size region beyond the long wavelength approximation regime. The observed degenerate-four-wave mixing signal of GaAs thin layers exhibits an anomalous size dependence, where the signal is resonantly enhanced at a particular thickness region. The theoretical analysis elucidates that this enhancement is due to the size-resonant enhancement of the internal field with a spatial structure relevant to the nondipole-type excitonic state. These results establish the formerly proposed new type of size dependence of nonlinear response due to the nonlocality induced double resonance. 相似文献
79.
Assuming that the effective magnetic moment operator is expressed in terms of one- and two-body operators which are not explicity specified, we study relations among magnetic moments and M1 rates in single-closed-shell nuclei. 相似文献