Polyvinyl alcohol (PVA) has been used to prevent flaking of paint pigments on traditional Japanese Shohekiga painted screens and panels. However, over time these PVA coatings whiten. To date, the mechanism of this whitening has not been studied from the point of view of polymer degradation. In this study, a piece of whitened PVA was obtained from a painted wooden panel. The PVA whitening mechanism was studied in this piece using scanning electron microscopy (SEM) and functional group analysis by Fourier transform-infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). SEM showed that the surface of the whitened PVA thin film was irregular and rugged, and many micrometer-sized cracks were observed. This suggests that efficient scattering of all visible light from the cracks causes whitening. FT-IR and XPS measurements revealed that inter-and intra-chain dehydration and chemical crosslinking (C-O ether linkage) occur on the surface of the whitened PVA.

Phthalocyanine (Pc)-based discotic liquid crystals could be prepared very rapidly by using our developed novel microwave-heating apparatus. It took only 10-20 min to synthesize these Pc metal complexes and metal-free Pc derivatives in an organic solvent (glycerin) by microwave irradiation, whereas it took 24-48 h to synthesize them by the conventional oil bath method. To our knowledge, it is the first example of metal-free Pc derivatives synthesized by microwave methods in an organic solvent. In the vast examples of Pc syntheses by conventional oil bath methods, the Pc metal complexes can be obtained in higher yields by "Template Effect" of the metal than the corresponding metal-free Pc derivatives. Therefore, we expected that the present Pc metal complexes (C n S) 8 PcCu (2) could be also prepared by microwave methods in higher yields than the metal-free Pc derivatives (C n S) 8 PcH 2 (1). Contrary to our expectation, the yields of the metal complexes (C n S) 8 PcCu (2) were lower than those of the metal-free derivatives (C n S) 8 PcH 2 (1). It is very interesting that this result by the microwave method is quite opposite to the results by conventional oil bath method. Hence, in this work we have focused our interest on the "Template Effect" in the syntheses of Pc derivatives by the microwave method in order to investigate the relationship between microwave heating and template effect. It is the first attempt in Pc syntheses by the microwave method.

We demonstrate the feasibility of in situ manipulation and characterization of individual carbon nanotubes using a nano-manipulation system operating inside a scanning electron microscope, which can also act as an electrical probing system. Transport characteristics of an individual multi-walled carbon nanotube in free space can be reversibly changed between linear and non-linear transport behaviour and are a result of changes in nanotube resistance.

There are about one to two radial resin canals per square millimeter in the tangential section of the late wood of each annual ring within a trunk in Larix leptolepis Gord. The diameter of radial resin canals is about 25 ).1m. In the annual ring in which there are typical traumatic resin canals in the early wood, the number of radial resin canals in the late wood is larger than that in the normal annual ring which was formed in the previous year, and it was sometimes observed that two closely spaced uniseriate rays became a multiseriate one containing a radial resin canal within one growth period.

ABSTRACT:The most difficult problem on syntheses of the phthalocyanine-based liquid crystals is the long reaction time. In order to shorten the reaction time, we have developed novel Methods A, B and D, for the syntheses of phthalocyanine-based liquid crystals by using microwave heating and/or adding a phase transfer catalysis of Aliquat 336. A series of phthalocyanine derivatives C n PcZn(1) (n = 10, 12, 14, 16 and 18: a, b, c and e) could be successfully synthesized in a dramatically short reaction time of 30-60 min using Methods A and B by microwave heating. On the other hand, anothor series of the derivatives C n (OH)PcZn (2a-2e) could not be synthesized by microwave heating. Therefore, all these derivatives were synthesized using conventional Method C by oil bath heating, but the reaction took a very long time (22.5-88 h). To shorten the reaction time, we have developed Method D by oil bath heating with adding a phase transfer catalyst of Aliquat 336. In this method, we successfully shortened the reaction time from 88 h to 3 h for the synthesis of the derivative 2a. Thus, the reaction time for oil bath heating can be also greatly shortened by adding the phase transfer catalyst of Aliquat 336. Furthermore, we have established from POM, DSC and temperature-dependent X-ray diffraction measurements that the derivative C 10 PcZn (1a) shows a very rare pseudohexagonal columnar (Col hr ) phase, and that the derivatives C n PcZn (1b-1e) and C n (OH)PcZn (2b-2e) exhibit spontaneous perfect homeotropic alignment in a large area between two glass plates in their Col tet phases.