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排序方式: 共有556条查询结果,搜索用时 15 毫秒
1.
Yoshiaki Yasuno Yasunori Sutoh Shuichi Makita Masahide Itoh Toyohiko Yatagai 《Optical Review》2003,10(5):498-500
A spectral interferometric optical coherence tomography (OCT) system which has polarization sensitivity is developed. This system reduces the mechanical scanning dimension by employing the principle of spectral interferometry, and measures a two dimensional cross-sectional image of biological tissue with one dimensional mechanical scanning. Sixteen OCT images with different polarization conditions are measured, and two dimensional distributions of each element of the Müller matrix of a sample to be measured are calculated. 相似文献
2.
The effect of surface modification with 3-aminopropyltriethoxysilane (APTES) and n-propyltriethoxysilane (PTES) on photo-catalytic activity and UV-shielding ability of fine TiO2 particles were investigated. The number of surface groups (NR) [nm−2] which shows the density of modifier on TiO2 surface was calculated from the results of elemental analysis and BET measurement. The modified samples of which NR are different were obtained by changing the concentration of modifier. When the photo-catalytic activity and UV-shielding ability of modified samples were evaluated, it was found that APTES was more effective modifier than PTES to obtained samples with low photo-catalytic activity and high UV-shielding ability. This is probably because the adsorption mechanisms on TiO2 surface between modifiers were different and NR is a key factor to control the performances of fine TiO2 particles. The result of zeta potential showed that surface character of modified samples was varied by changing NR. It suggested from these results that NR affected the photo-catalytic activity and UV-shielding ability because NR changed surface character of modified samples. 相似文献
3.
Masahide Terazima 《Research on Chemical Intermediates》1997,23(9):853-901
In this article, applications of the TG method to measurements of the translational diffusion of photochemically created intermediate species are reviewed. The intermediate species include unstable isomers, photochromic charged molecules, transient radicals created by photochemical reactions, and the electronically photoexcited species. Diffusional behaviors of these intermediates are different from those of stable molecules, which have been investigated extensively so far. The investigations of the diffusion of these species will provide opportunity to reveal the unique intermolecular interaction between the intermediates and matrix. Furthermore, by using products of photochemical reactions as probe molecules, the molecular dynamics of the system can be studied. This information will be valuable for understanding photochemistry in solution. 相似文献
4.
5.
A nitro-introduced Wang resin-type linker for soluble and insoluble polymer support oligosaccharide synthesis is described. The linker was used for connecting glycosyl donors and polymer supports, and was completely stable under the glycosylation conditions tested. The cleavage of the linker was performed under reductive conditions without affecting the protecting groups to release disaccharides. 相似文献
6.
Seiji Shinkai Youichiro Hara Osamu Manabe 《Journal of polymer science. Part A, Polymer chemistry》1982,20(4):1097-1105
Three thiazolium-containing polymers, Th-7, Th-33, and Th-18-Py [where Th-x and Py mean x mol % thiazolium unit and pyridinium unit (54 mol %), respectively], were synthesized from partially p-chloromethylated polystyrene. The catalytic activities of these polymer catalysts in acyloin condensation of aldehydes and decarboxylation of α-keto acids were estimated kinetically by oxidative trapping of the key intermediate by flavin (flavin-trapping technique). In aqueous solution at 30°C, the catalytic activity of Th-18-Py and Th-33 in condensation of p-chlorobenzaldehyde was comparable with that of the cationic-micelle-bound thiazolium ion, whereas Th-7 and a monomeric thiazolium compound (N-benzylthiazolium bromide) scarcely exhibited any catalytic activity. The catalysis of the polymer-bound thiazolium ions was sensitively suppressed by increased ionic strength. These results suggest that the pendent thiazolium ion is activated by the relatively high charge density along the polymer chain: the cationic environment is able to facilitate dissociation of the thiazolium ion to the ylid form and deprotonation of the thiazolium-aldehyde adduct to the key intermediate. 相似文献
7.
8.
Masahiro Manabe Asako Tokunaga Hideo Kawamura Hajime Katsuura Masaki Shiomi Koichi Hiramatsu 《Colloid and polymer science》2002,280(10):929-935
In the micellar solution of SDS, the partition coefficient (Kx) of following branched alkanols at infinite dilution was determined by applying a differential conductivity method: the alkanols used were i-CmH2m+1OH (m=4-9, i=1-5) in which the position of OH group (i) shifts from an end to the center of a hydrocarbon chain. The method provides two significant quantities, d!/dXam and dCsf/dCaf in addition to Kx. The following results have been obtained. (1) The dependence of Kx on i indicates that the hydrophobicity of alkanol is weakened with increasing i, whereas the increase in m strengthens the hydrophobicity. (2) The degree of counterion disossiation of micelles (!) is accelerated by the solubilized alkanols in micelles (mole fraction: Xam) and the acceleration rate, d!/dXam (=0.17), depends on neither m nor i. (3) In the bulk water, the monomerically dissolved alkanols (concentration: Caf) depresses the concentration of free monomer surfactant (Csf), and the depressing rate, dCsf/dCaf, in micellar solution is identical with the corresponding quantity, ((CMC/(Ca)o at CMC. 相似文献
9.
Manabe K Iimura S Sun XM Kobayashi S 《Journal of the American Chemical Society》2002,124(40):11971-11978
Dehydration reactions in water have been realized by a surfactant-type catalyst, dodecylbenzenesulfonic acid (DBSA). These reactions include dehydrative esterification, etherification, thioetherification, and dithioacetalization. In these reactions, DBSA and substrates form emulsion droplets whose interior is hydrophobic enough to exclude water molecules generated during the reactions. Detailed studies on the esterification revealed that the yields of esters were affected by temperature, amounts of DBSA used, and the substrates. Esters were obtained in high yields for highly hydrophobic substrates. On the basis of the difference in hydrophobicity of the substrates, unique selective esterification and etherification in water were attained. Furthermore, chemospecific, three-component reactions under DBSA-catalyzed conditions were also found to proceed smoothly. This work not only may lead to environmentally benign systems but also will provide a new aspect of organic chemistry in water. 相似文献
10.
Masahide Shimokawabe Atsushi Ohi Nobutsune Takezawa 《Reaction Kinetics and Catalysis Letters》1994,52(2):393-397
Over metal oxides (SiO2, ZrO2, Al2O3, MgO, La2O3, and CaO) with-H values of metal oxide formation higher than 700 kJ/mol, C3H6 reacts with NO2 in preference to O2. 相似文献