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Shinichi Kinugasa Hisae Nakahara Jun-Ichi Kawahara Yoshinori Koga Haruo Takaya 《Journal of Polymer Science.Polymer Physics》1996,34(3):583-586
Static light scattering measurements were performed on dilute solutions of monodisperse poly(ethylene oxide) (PEO) in methanol at 25°C. PEOs of five different molecular weights ranging from nominal Mw = 8.6 × 104 to 9.13 × 105 were used. Linear Zimm plots were obtained for all the PEO samples: no downturn was observed at small angles, indicating that no large aggregates of PEO molecules exist in the solution. From the plots, values of the weight-average molecular weight, Mw, the radius gyration, RG, and the second virial coefficient, A2, were successfully determined for respective PEOs. Observed relationship between RG and Mw indicates that methanol is certainly a good solvent for the polymer. © 1996 John Wiley & Sons, Inc. 相似文献
84.
Masahisa Wada Takeshi Okano Junji Sugiyama Fumitaka Horii 《Cellulose (London, England)》1995,2(4):223-233
We have investigated unlignified tension wood and normally lignified wood celluloses inPopulus maximowiczii with particular reference to the composition of two crystalline phases I/I (triclinic/ monoclinic). Four independent techniques, which enable us to detect the two phases, CP/MAS13C NMR, Fourier transform infrared microscopy, selected-area electron diffraction, and X-ray diffraction were applied. Because of the low crystallinity of wood celluloses, particularly in the case of celluloses in the lignified cell wall, no single method was decisive enough to be able to determine the composition of the two phases as one can with highly crystalline materials. The I dominant structure (monoclinic crystal type) was, however, preferred for both tension and normal wood celluloses. 相似文献
85.
Spatial and seasonal variations in attenuation of solar ultraviolet radiation in Lake Biwa, Japan 总被引:2,自引:0,他引:2
Seasonal changes in diffuse ultraviolet (UV) and visible light attenuations and inherent optical properties in the lake water were monitored at the pelagic and littoral shallow zones of Lake Biwa which features a broad range of optical conditions within a single large water body. We considered the absorption factors that affect UV attenuation, and clarified the contribution of the absorption of suspended particles and chromophoric dissolved organic matter (CDOM) by multiple regression analyses of the monitoring data. The variability of UV attenuations in the lake demonstrated a strong contrast between the pelagic and the shallow zones. The latter were characterized by turbid systems supplying suspended matter as well as CDOM, whereas the former was far from the turbid systems in the littoral zone or the lake bottom. In this lake, the regulation of UV and light attenuations is rendered competitive by the absorption of suspended particles and CDOM in the lake water, hence, the UV penetration has both spatial and temporal variability based on changes in the physical and biological condition of the lake. 相似文献
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Ito S Sugiyama H Yoshifuji M 《Angewandte Chemie (International ed. in English)》2000,39(15):2781-2783
88.
K. Sugiyama 《Colloid and polymer science》1978,256(2):204
Ohne Zusammenfassung 相似文献
89.
A new synthetic approach to quinazolines bearing a carboxy group is described. Reaction of 5-carbonyl substituted 1,3,6-tri-methyluracils (I) with dimethyl acetylenedicarboxylate or electron-deficient olefines affords quinazoline derivatives (III-VI) pyrimidine(Z)-dienols (II) formed by base-catalyzed isomerization. 相似文献
90.