The Pt-catalyzed carboselenation of alkynes by selenoesters

[reaction: see text] The Pt-catalyzed carboselenation of terminal alkynes with selenoesters provided vinylselenides regio- and stereoselectively in moderate yields.     

Free Field Construction for the ABF Models in Regime II

The Wakimoto construction for the quantum affine algebra U $_q$ ( $(\widehat{\mathfrak{s}\mathfrak{l}_2 })$ ) admits a reduction to the q-deformed parafermion algebras. We interpret the latter theory as a free field realization of the Andrews–Baxter–Forrester models in regime II. We give multi-particle form factors of some local operators on the lattice and compute their scaling limit, where the models are described by a massive field theory with $\mathbb{Z}$ $_k$ symmetric minimal scattering matrices.     

Numerical analysis of turbulent flow separation in a rectangular duct with a sharp 180‐degree turn by algebraic Reynolds stress model

Turbulent flow in a rectangular duct with a sharp 180‐degree turn is difficult to predict numerically because the flow behavior is influenced by several types of forces, including centrifugal force, pressure‐driven force, and shear stress generated by anisotropic turbulence. In particular, this type of flow is characterized by a large‐scale separated flow, and it is difficult to predict the reattachment point of a separated flow. Numerical analysis has been performed for a turbulent flow in a rectangular duct with a sharp 180‐degree turn using the algebraic Reynolds stress model. A boundary‐fitted coordinate system is introduced as a method for coordinate transformation to set the boundary conditions next to complicated shapes. The calculated results are compared with the experimental data, as measured by a laser‐Doppler anemometer, in order to examine the validity of the proposed numerical method and turbulent model. In addition, the possibility of improving the wall function method in the separated flow region is examined by replacing the log‐law velocity profile for a smooth wall with that for a rough wall. The analysis results indicated that the proposed algebraic Reynolds stress model can be used to reasonably predict the turbulent flow in a rectangular duct with a sharp 180‐degree turn. In particular, the calculated reattachment point of a separated flow, which is difficult to predict in a turbulent flow, agrees well with the experimental results. In addition, the calculation results suggest that the wall function method using the log‐law velocity profile for a rough wall over a separated flow region has some potential for improving the prediction accuracy. Copyright © 2007 John Wiley & Sons, Ltd.     

Adsorption behavior of VII group elements on tertiary pyridine resin in hydrochloric acid solution

We investigated the adsorption behaviors of technetium and rhenium on tertiary pyridine resin in hydrochloric acid solution. Technetium has a little larger distribution coefficient in higher concentration of hydrochloric acid region than rhenium. However, the tendency of adsorption behavior of technetium and rhenium is similar. We concluded that the rhenium can be used as the substitute for technetium. Adsorption behaviors of platinum group elements were also investigated. The separation of technetium from platinum group elements is discussed.     

Phase transition behavior and proton conduction mechanism in cesium hydrogen sulfate/silica composite

Proton conduction and crystal structure in CsHSO₄/SiO₂ composite composed of polycrystalline CsHSO₄ and mesoporous silica particles were investigated based on conductivity measurement and characterizations using Raman spectroscopy, XRD, and differential thermal analysis. The conductivity of pure CsHSO₄ abruptly changes at around 414 K (superprotonic phase transition), being accompanied with the structural transformation from a monoclinic phase to a tetragonal phase, while the conductivity of CsHSO₄/SiO₂ composite is significantly larger by over three orders of magnitude than that of pure CsHSO₄ below the critical temperature of the superprotonic phase transition (353-414 K). Raman spectroscopy and XRD indicate that this remarkable conductivity-enhancement in the composite is not due to the stabilization of the tetragonal phase (superprotonic phase) below its critical temperature. The line-broadening of the internal modes in the Raman spectra suggests that the rapid reorientational motion of the HSO₄⁻ ion, which leads to superprotonic conduction, is induced in the composite even below the critical temperature. The reorientational motion of the HSO₄⁻ ion below the critical temperature will occur at the interfacial phase which is structurally disordered and forms between CsHSO₄ and SiO₂ in the mesopores and/or on the surfaces of silica particles. Proton transfer will be accelerated via the interfacial conduction-pathway in the composite.     

Allylation of methylenecyclopropanes with allylindium reagents

Methylenecyclopropanes carrying a hydroxymethyl group at the ring underwent stereoselective allylindation with allylindium sesquiiodide to afford the allylated products, in which the allyl group was delivered at the external sp² carbon via cyclopropylindium intermediates. The reaction of ethyl 2-cyclopropylideneacetate and triallylindium afforded the 1,4-adduct along with dimeric products.