Nonequilibrium MHD plasma flow in a high-interaction disk generator

Nonequilibrium MHD plasma flow in a high-interaction disk-type MHD generator is examined by numerical simulations based on the two-temperature model equations. The simulations are performed for the generators driven by working gases: He-Cs and He-K. Homogeneous and inhomogeneous plasma behavior is observed with change of the load resistance, and it is found that the structures of the inhomogeneous plasma differ for different seed materials. The plasma structures associated with both the partial ionization instability and the magnetoacoustic instability are discussed for both plasmas     

Effects of tertiary amine accelerators on curing of epoxide resins

The effects of seven tertiary amine accelerators on curing of bisphenol-type epoxide resins using azelaic acid as a curing agent have been investigated. The structure of the cured resins is characterized and reaction and structure schemes are proposed. The reaction mechanism and the resulting structure of the resin depend on the basicity of the accelerator. With increasing accelerator basicity crosslinking in the cured resin increases. Characterization results indicate that the network structure consists of ether bonds or a mixture of ether and ester bonds; the linear structure consists of only ester bonds. The structure and, therefore, the properties of the cured epoxide resin may thus be regulated by selection of the amine basicity.     

Iridium complex-catalyzed [2+2+2] cycloaddition of alpha,omega-diynes with monoynes and monoenes

[reaction: see text] [Ir(cod)Cl]2/DPPE was found to be a new catalyst for the cycloaddition of alpha,omega-diynes with monoynes to give polysubstituted benzene derivatives in high yields. Internal monoynes as well as terminal monoynes could be used. The reaction tolerates a broad range of functional groups such as alcohol, amine, alkene, ether, halogen, and nitrile. The reaction of 1,6-octadiyne derivatives with 1-alkynes gives ortho products and meta products. The regioselectivity could be controlled by the choice of ligand. The reaction with DPPE was meta selective, with meta selectivity of up to 82%. The reaction with DPPF was ortho selective, with ortho selectivity of up to 88%. We propose a mechanism to account for this regioselective cycloaddition. [Ir(cod)Cl](2)/DPPE also catalyzed the cycloaddition of alpha,omega-diynes with 2,5-dihydrofuran to give bicyclic cyclohexadiene derivatives. The reaction with 2,3-dihydrofuran and n-butyl vinyl ether gave benzene derivatives instead of cyclohexadiene derivatives. We also propose a mechanism to account for this novel aromatization that includes cleavage of the C-O bond.     

Synthesis of (1-alkynyl)dicarbonylcyclopentadienyliron complexes by palladium-catalyzed Sonogashira-type carbon-iron bond formation

Treatment of [CpFe(CO)₂I] with terminal alkynes in the presence of catalytic amounts of dichlorobis(triphenylphosphine)palladium and copper iodide in aliphatic amine/THF results in Sonogashira-type carbon-iron bond formation to yield [CpFe(CO)₂(CCR)] in good yields.     

Space-selective phase separation inside a glass by controlling compositional distribution with femtosecond-laser irradiation

Space-selective phase separation was induced inside Na₂O–SiO₂ glasses by changing the glass composition locally from a miscible composition to an immiscible one via femtosecond-laser irradiation at a high repetition rate. The formation of a nanoscale co-continuous structure due to phase separation was confirmed by scanning electron microscopy after heat treatment, polishing until the laser-modified area was exposed, and subsequent etching. The configuration of the structure could be controlled by changing the heat-treatment time.     

A liquid film or droplet of miscible binary fuel burning on a heated surface at elevated pressures

An experimental study has been made of the combustion and evaporation of miscible binary fuels on a heated surface at elevated pressures. Photographic observation was made for elucidating how the binary fuel droplets or films behaved on the heated surface and for obtaining the characteristic lifetime as a function of the surface temperature, the ambient pressure and the initial concentration of highly volatile component of the fuels. The binary fuels tested were mixtures of n-hexane and n-decane. The results showed that the lifetime curve both for the combustion and for the evaporation of n-hexane/n-decane on the heated surface had two peaks at lower pressures, the first peak in the film-type evaporation region and the second peak in the spheroid-type evaporation region. The preferential evaporation of the highly volatile component was responsible for the appearance of the first peak in the film-type evaporation region. The second peak corresponded to Leidenfrost point. The increase in the ambient pressure caused a shift of the lifetime curve toward higher surface temperature and a decrease in the lifetime at two peaks. The lifetime curve decreased monotonically with increasing the surface temperature and the spheroid-type evaporation was not observed at higher pressures. The increase in the initial concentration of highly volatile component caused a shift of the first peak toward higher surface temperature, a decrease in its lifetime and a slight shift of the second peak toward lower surface temperature. The combustion caused a remarkable decrease in the lifetimes around the first peak and in the spheroid-type evaporation region and a slight increase in the surface temperature at the first peak, while the surface temperature at the second peak remained almost unchanged.     

Preparation and Polymerization of 2-(Phthalimido)ethyl 10′-(Methacryloyloxy)decyl Hydrogen Phosphate

The preparation and polymerization of 2-(phthalimido)ethyl 10′-(methacryloyloxy)decyl hydrogen phosphate are described. This monomer was polymerized with 2, 2′-azobisisobutyro-nitrile (AIBN). The properties of the resultant polymer are also described.     

Monolayers and Multilayers of Amphiphilic Phospholipid Analogous Poly(Acrylamide)s

Abstract

A series of amphiphilic phospholipid analogous acrylamide monomers and homopolymers containing long alkyl chains as the hydrophobic groups and phosphatidylcholine analogues as the hydrophilic groups were used to study the properties of monolayers and multilayers. The P-A isotherms of the monolayers for these monomers and polymers were measured at different temperatures. The temperature and length dependence of alkyl chains, and the difference between monomers and polymers were investigated, respectively. On the other hand, the LB multilayers of all monomers and polymers were prepared. The contact angles of LB films obtained with pure water were also measured.     

Resveratrol derivatives from Upuna borneensis

Four new resveratrol derivatives, upunaphenols B (1), C (4), D (5) (resveratrol tetramer) and E (6, resveratrol dimer with a C6-C1 unit), together with nine known resveratrol oligomers and resveratrol were isolated from an acetone soluble part of stem of Upuna borneensis (Dipterocarpaceae). The structures of new compounds were determined by spectral analysis including 1D and 2D NMR experiments.     

Columnar Liquid Crystals from a Giant Macrocycle Mesogen

Columnar liquid crystals composed of a giant macrocyclic mesogen were prepared. The giant macrocyclic mesogen has a square hollow with a 2.5 nm diagonal, which was bounded by diindolo[3,2‐b:2′,3′‐h]carbazole (diindolocarbazole) moieties as the edges and bis(salicylidene)‐o‐phenylenediamine (salphen) moieties as the corners. The shape and size of the macrocycle were directly observed by scanning tunneling microscopy (STM). Each side of the bright square in the STM image corresponds to a diindolocarbazole moiety, and the length of the sides was consistent with the result of the single crystal analysis of diindolocarbazole. Finally, we successfully obtained a giant macrocycle with long and branched side chains, which exhibited a rectangular columnar LC phase over a wide temperature range. To the best of our knowledge, it contained the largest discrete inner space of any thermotropic columnar liquid crystal composed of macrocyclic mesogens.