Abstract: A cubic boron nitride sintered material comprising cubic boron nitride grains and a binder, in which a content of the cubic boron nitride grains is no less than 30% by volume and no more than 80% by volume, the binder includes at least one selected from a second group consisting of a material made of a single element selected from a first group consisting of a group 4 element, a group 5 element and a group 6 element of the periodic table, aluminum, silicon, iron, cobalt and nickel, and an alloy and an intermetallic compound each composed of no less than two elements selected from the first group, and a content of a void in the cubic boron nitride sintered material is no less than 0.001% by volume and no more than 0.20% by volume.

Abstract: An impedance matching device provided between a high-frequency generator and a load device matches an impedance of the high-frequency generator with an impedance of the load device and includes at least a coupled circuit which comprises a core, and a main winding and a control winding which are wound around the core. The coupled circuit changes an impedance of the impedance matching device by changing an inductance value of the main winding which depends on a magnitude of direct current flowing in the control winding.

Abstract: Disclosed is a process for producing novel optically active titanium alkoxide complexes which are excellent in catalytic activity and enantio-selectivity in carbon-carbon bond forming reactions (for example, Ene reaction, hetero-Diels-Alder reaction, Aldol reaction) and have high stability. The present process comprises reacting (R),(S),(RS)-catalysts or mixtures thereof selected from among optically active or racemic titanium alkoxide complexes represented by the following general formula (1), etc.: ##STR1## wherein R.sup.1 represents a methyl, lower alkoxy or trihalogeno group; R.sup.2 represents a hydrogen or halogen atom; R.sup.3 represents a hydrogen atom or a methyl group; and R.sup.4 represents a lower alkyl group, or R.sup.1 and R.sup.2 may form together a cyclo ring;with chiral activators [(R),(S),(RS)-diols or mixtures thereof, but excluding reactions between a racemic modification and another racemic modification] to thereby activate exclusively one of the enantiomers.

Abstract: A process for producing an optically active .beta.-hydroxyketone represented by formula (I): ##STR1## by catalytic asymmetrical aldol reaction is disclosed, comprising reacting a silyl-enol ether represented by formula (II): ##STR2## with a substituted aldehyde represented by formula (III):R.sup.5 CHO (III)in the presence of a binaphthol-titanium complex represented by formula (IV): ##STR3## An optically active .beta.-hydroxyketone is efficiently produced with diastereo-specificity and enantio-specificity.