Analysis of anisotropy of high Tc superconducting oxides using multi-CuO2-layer structure model

The anisotropy of high Tc superconducting oxides such as Bi₂Sr₂Ca₁Cu₂O₈ is analized by use of the multi-CuO₂-layer structure model. It is found that the anisotropy decreases when Tc increases. Under high pressure, the anisotropy also decreases.     

A Novel Spread Function for Observation of Random Surface

When a random rough surface is viewed obliquely by an imaging system, the position of a viewed point fluctuates with surface displacements. This fluctuation introduces an additional blur to the images that are mapped on the average surface. A new class of spread function, which represents the resolution associated with the randomness of an imaging object, is introduced to treat this problem and an analytical expression of the function is obtained for a Gaussian random surface under the presence of shadowing effects. This spread function is useful in understanding the loss in resolution of images of a random surface such as the thermal imagery of an ocean surface in the near horizon.     

Drying and weighing of standard reference materials for titrimetric analysis, and the status of the faraday constant as an international standard

A review is given of the methods of drying standard reference materials, and handling them after drying. The status of the Faraday as an international reference standard for titrimetric analysis is also discussed.     

Photoreactive fluorinated polyimide protected by tetrahydropyranyl (THP) group based on chemical amplification: Acid generation in polyimide film and lithographic properties

The photochemistry of photoacid generator (PAG), diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS) and diphenyliodonium 8-anilinonaphthalene-1-sulfonate (DIANS) was investigated in both alkalinesoluble polyimide (6FDA-AHHFP) and novolak films. The quantum yields of photodissociation of DIAS and DIANS in both 6FDA-AHHFP and novolak films. The quantum yields of photodissociation of DIAS and DIANS in both 6FDA-AHHFP and novolak films were determined as 0.11, 0.21, 0.12 and 0.26, respectively. On the other hand, the quantum yields for acid generation from DIAS and DIANS in both of these films were 0.07, 0.18, 0.09 and 0.22, respectively, in the presence of an acid indicator. These results indicate that the values of the quantum yields of photodissociation and photoacid formation for DIAS and DIANS in 6FDA-AHHFP film are lower than those in novolak film. In order to elucidate the lowering of the quantum yields in 6FDA-AHHFP film, fluorescence quenchings of sodium 9,10-dimethoxy-anthracene-2-sulfonate and ammonium 8-anilinonaphthalene-1-sulfonate by a model compound of polyimide was carried out in acetonitrile. The fluorescences of these two salts were efficiently quenched by the model compound with the diffusion-controlled rate constant in acetonitrile, suggesting that a strong electron-accepting capability of the imide carbonyl group may hinder the electron transfer process within PAG molecules in 6FDA-AHHFP film. Although a polyimide (6F-THP) protected by tetrahydropyranyl group is insoluble in aqueous base, 6F-THP film containing PAG became soluble in a 2:1 mixture of 2.0 wt% tetramethylammonium hydroxide (TMAH) and methanol by exposure to 365 nm light and successive post-exposure baking (PEB) at 120°C for 10 min. The sensitivity and contrast of 6F-THP with DIANS after the PEB conditions mentioned above were 110 mJ/cm² and 3.7, respectively. A high-resolution pattern with a good profile was transferred into the 3 μm thickness of the 6F-THP film.     

Bandwidth analysis of solvation dynamics in a simple liquid mixture

The time-dependent energy distribution of solvation dynamics is studied by molecular dynamics simulations of a Lennard-Jones mixture. We calculate the response functions of the average and the variance which correspond to the spectral peak shift and bandwidth. Our calculation shows that the variance relaxation is slower than that of the average. The result agrees qualitatively with the experimental results. Dividing the obtained response functions into subcomponents caused by each solvent, we find that the relaxation is dominated by that solvent which strongly interacts with the solute. Extracting the redistribution component from the response functions, we find that it causes the slower relaxation of the response function. Thus, we conclude that the difference of the slower relaxations between the average and variance is caused by the redistribution process.     

Michael-type reaction of ethyl bromodifluoroacetate with alpha,beta- unsaturated carbonyl compounds in the presence of copper powder

We have reported that the reaction of ethyl bromodifluoroacetate (1) with alkenyl iodides in the presence of copper powder gives ethyl alkenyldifluoroacetates. As an extension of this reaction, reaction of 1 with Michael acceptors in the presence of copper powder was examined and found to give 1,4-addition products selectively, unless the acceptor has a group stabilizing a radical intermediate, such as a phenyl group.     

Photochemical Reactions of Tetrahydroquinoxalin-2(1H)-ones and Related Compound

Photochemical behaviors of the pyrazinone derivatives 5,6,7,8-tetrahydroquinoxalin-2(1H)-ones 1a – c and 1,5,6,7,8,9-hexahydro-2H-cyclohepta[b]pyrazin-2-one 1d were investigated. Dye-sensitized photo-oxygenation of 1a-c gave the 1:1 adducts 5a – c of the corresponding 3,8a-epidioxy-3,5,6,7,8,8a-hexahydroquinoxalin-2(1H)-one 4 and H₂O, whereas 1d gave 3,9a-epidioxy-1,3,5,6,7,8,9,9a-octahydro-2H-cyclohepta[b]pyrazin-2-one 4d (Scheme 2). The different kind of products was interpreted as being the result of the ring strain and steric hindrance of endoperoxides produced from 1a – d with singlet oxygen. Irradiation of 1a – b in the presence of alkenes gave tricyclic azetidine derivatives 9 by [2 + 2] cycloaddition of the C?N bond of 1 to the alkene.     

The reformatsky reaction of 1-aryl-2(1H)pyrimidinones

1-Aryl-2(1H)pyrimidinones I reacted with α-haloesters in the presence of zinc to give mainly 3,4-dihydro-4-alkoxycarbonylmethyl-1-aryl-2(1H)pyrimidinones IV in addition to the minor products of 3,6-dihydro-6-alkoxycarbonylmethyl-1-aryl-2(1H)pyrimidinones V. Further, 3,4-dihydro derivatives IVa-c were successfully converted into the corresponding exomethylene compounds Vla-c in high yields.     

Preparation of N-aryl-2,4-diaminopentanes by the ring opening reaction of 1-aryl-3,4,5,6-tetrahydro-2-(1H)pyrimidinones

1-Aryl-3,4,5,6-tetrahydro-2-(1H)pyrimidinones (I) underwent reductive ring opening reaction with lithium aluminum hydride to afford N-aryl-2,4-diaminopentanes (II) in good yields. On the other hand, 3,4,5,6-tetrahydro-3,4,6-trimethyl-1-phenyl-2-(1H)-pyrimidinone (V) gave only cyclic diamine, 3,4,6-trimethyl-1-phenylhexahydropyrimidine (VI), in 60% yield.