Organocatalytic head-to-tail dimerization of methacrolein via conjugate addition of methanol: an alcohol activation mechanism proved by electrospray ionization mass spectrometry

The head-to-tail dimerization of methacrolein via the conjugate addition of methanol is catalyzed by various organic bases, such as an amine, phosphine, and N-heterocyclic carbene, to give 2,4-dimethyl-2-methoxymethylpentane-1,5-dial in moderate yields. Based on the interpretation of the key intermediates by electrospray ionization mass spectrometry, we propose a reaction mechanism involving the initial conjugate addition of the organic bases to methacrolein to generate a zwitterionic base followed by the activation of methanol.     

Quantum numerical control for free elementary particle

This work is to survey the quantum control for free elementary particle numerically. Without considering of the magnetic and electronic fields, control theory of nucleus (nucleons and meson) will be proposed. Furthermore, computational approach will be preformed for control landscape in two dimensions (2D) to illustrate the theoretic results.     

Adjoint-based exact Hessian computation

BIT Numerical Mathematics - We consider a scalar function depending on a numerical solution of an initial value problem, and its second-derivative (Hessian) matrix for the initial value. The need...     

Stability of a system of Volterra integro-differential equations

Using new and known forms of Lyapunov functionals, this paper proposes new stability criteria for a system of Volterra integro-differential equations.     

Observation of phase transition of cesium manganese hexacyanoferrates by X-ray absorption spectroscopy

Cesium manganese hexacyanoferrates exhibit an interesting phenomenon of temperature-induced phase transition accompanied by a variation in the magnetic susceptibility. We observed the variation in the electronic state of Mn during the phase transition by using X-ray absorption spectroscopy. The results of the analyses showed that the content ratio of Fe^II-CN-Mn^III and Fe^III-CN-Mn^II systematically varied during the phase transition. However, the ratio of Fe^II-CN-Mn^II remained constant at almost all temperatures. These results suggest that the charge transfer between Fe and Mn ions in the Fe^III-CN-Mn^II or the Fe^II-CN-Mn^III bond produces the phase transition.     

Parameter identification problem for the equation of motion of membrane with strong viscosity

The parameter identification problem of constant parameters in the equation of membrane with strong viscosity is studied. The problem is formulated by a minimization of quadratic cost functionals by distributive measurements. The existence of optimal parameters and necessary optimality conditions for the parameters are proved.     

Recent trends of industrial catalysts for resid hydroprocessing in Japan

To meet the gradual changes in petroleum demand, in particular a reduced demand for heavy fuel oil, advanced technology for resid hydroprocessing is now extremely necessary. The catalyst technology for resid hydroprocessing in Japan, especially fixed bed type of hydrodesulfurization and hydroconversion, is reviewed in this article.     

Iodoetherification of 4-penten-1,3-diols: stereoselective synthesis of cis 2-iodomethyl-3-hydroxytetrahydrofurans

cis 2-Iodomethyl-3-hydroxytetrahydrofurans have been obtained in high yields and in high selectivities by treatment of 4-penten-1,3-diols with iodine (ether-H₂O, NaHCO₃).     

Novel oxy-perfluoroalkylation

(Perfluoroalkyl)phenyliodonium sulfonates underwent novel oxy-perfluoroalkylation with alkenes under oxygen atmosphere in the presence of a base.