Studies on Lewis acid-mediated intramolecular cyclization reactions of allene-ene systems

The Lewis acid-mediated reactions of allene-ene compounds, derived from 3-methylcitronellal or dimethyl malonate, were carried out using various Lewis acids such as ethylaluminum dichloride, diethylaluminum chloride, titanium chloride, zinc chloride etherate, or boron trifluoride etherate, affording unexpectedly intramolecular [2+2]cycloaddition products under some particular reaction conditions without any formation of intramolecular ene reaction products.     

Nanoparticle Formation Mechanism in CVD Reactor with Ionization of Source Vapor

A new chemical vapor deposition (CVD) method, called ionization CVD, was developed, to produce non-agglomerated nanoparticles in which reactant gases are charged. A sonic-jet corona discharger was used as an ionizer in the developed nanoparticle generator. For a tetraethylorthosilicate (TEOS)/O₂ chemical system, SiO₂ nanoparticles were prepared. All particles formed by the ionization CVD were charged unipolarly. SEM micrographs of particles showed that the repulsive Coulombic force between charged particles reduces their coagulation rate and produces non-agglomerated nanoparticles that have a relatively high number concentration and small size. An external field was used to collect the charged particles onto Si wafers. These collected samples indicated that the deposition of charged particles could be controlled by the external electric field. Particle concentration measurement with a condensation nucleus counter at various TEOS concentrations suggested the particle formation mechanism in the ionization CVD was an ion-induced nucleation.     

Nuclear Spin Maser Oscillation of 129Xe by Means of Optical-Detection Feedback

We have developed the nuclear spin maser oscillating at a low frequency of 34 Hz with highly polarized nuclear spins of the noble gas element ¹²⁹Xe. The system is advantageous for detecting a small frequency shift of the nuclear spin precession. We are thus planning to apply this system to the search for an atomic electric dipole moment of ¹²⁹Xe. We here report the development of the system and its performance.     

Bending vibration analysis of rotating machineries using multibody dynamics technology — development of computer program RotB

This paper examines a computer program developed to analyze the vibration of rotating machineries based on theories of vibration and multibody dynamics (MBD). Bending vibration problems of rotating machineries have generally been categorized as either linear or nonlinear. Linear problems can be formulated by standard methods and nonlinear problems can be formulated by MBD methods. In our study, nonlinear problems are treated by the use of a general-purpose computer program, RecurDyn (RD). In the program we developed, rotor bending vibration analysis (RotB) structural properties such as shafts, rotating rotary disks, unbalanced masses and foundation structures are modeled as multibody elements. Also, nonlinearities such as contact, non-symmetrical shaft effects, bearing characteristics, nonlinear restoring and damping characteristics in the bearings are taken into account. The computational results demonstrate the validity of RotB.     

Progresses of coal liquefaction catalysts in Japan

Research and development of catalysts and their performances for coal liquefaction are reviewed, enphasizing the contribution of recent 20 years from Japan. A variety of iron based catalysts were extensively examined to define the pyrrhotite as the active species produced in the liquefaction process. Synthetic pyrite, synthesized hydroxy ferric oxide, finely ground pyrite and limonite have been applied in the process development of coal liquefaction. Iron impregnation onto coal particles using waste water was examined also in a continuous-flow reactor. Finer particles were found to reduce significantly the amount of the catalyst to obtain the same oil yield. Usefulness of such catalysts is proved in the continuous operation of a large scale pilot plant. Iron, iron–nickel, and iron–molybdenum sulfides were found to be active catalysts when they are supported on nano-particles of carbon. Catalysts for recovery and repeated use and for selective aromatic ring opening are under current research.     

Conjugate addition of alkyl groups to α,β-unsaturated sulfoxides via Michael addition of nitroparaffins and subsequent denitration with tributyltin hydride

Michael addition of nitroparaffins to α,β-unsaturated sulfoxides is well effected in the presence of DBU. The nitro group in the adduct is replaced by hydrogen with Bu₃SnH without influence to the sulfinyl function. The overall reations provide an efficient method for the conjugate addition of alkyl groups to α,β-unsaturated sulfoxides.