Abstract: Provided is a method for producing a phenol condensate by oxidative condensation of a phenol compound not having a substituted group on at least one ortho-position, in the presence of a specific complex (II) and oxygen, wherein a condensate coupled at para-position of the phenol can be produced in an excellent yield, L-M (X)n??(II) wherein L represents a ligand having 2 to 4 nitrogen atoms as donor atoms, M represents copper ion, nickel ion, cobalt ion, iron ion, manganese ion, chromium ion or vanadyl ion, X represents a counter ion, n is a number of Xs.

Abstract: Provided is a method for producing a phenol condensate by oxidative condensation of a phenol compound not having a substituted group on at least one ortho-position, in the presence of a specific complex (II) and oxygen, wherein a condensate coupled at para-position of the phenol can be produced in an excellent yield,

Abstract: A tachogenerator has a magnetoresistance film coil formed on a stator surface along a circular path concentric with a rotor axis. The coil has a spatially periodic structure, with multiple spaced-apart lateral components series connected with longitudinal components. The stator surface is opposite to a rotor surface having multiple equiangularly spaced magnetic pole faces with alternately opposite polarities. Current passed through the coil develops voltage variations. Undesirable small voltage variations resulting from manufacturing tolerances are averaged to zero at the coil output terminals.

Abstract: A rotation control device causes a disc on which information and sync signals are recorded to rotate at a predetermined speed. The control device includes a generator for generating a signal whose frequency is identical with that of a rotation signal which will be output from a frequency generator while the disc rotates at the predetermined speed. A control loop is defined which compares a phase of an output of the signal generator and a rotation signal output from the frequency generator, thereby controlling the drive of the motor.

Abstract: A direct current brushless motor is structured by fixing a ring-shape magnetic rotor to a rotor shaft in one piece by way of the magnet yoke, and by arranging the position of the insulating plate on which the magnetic induction elements for detecting the magnetic field of the rotor magnet, stator windings and the rotor yoke are installed, so as to have the rotor magnet oppose the stator windings across an air gap. The stator windings are composed of delta connection wirings and the windings of each phase are placed on a concentric circle having the rotor shaft at its center and in a position dividing the said circle in equiangular areas.The magnetic induction elements are provided in three with the first, second and third elements being respectively fixed at the positions where their respective phases are advanced by .pi./6 radian in the electric angle from the respective centers of the first phase, second phase and third phase coils.