Abstract: A system frequency detector includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average; and a frequency calculator including an angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal, and an arithmetic unit calculating a system frequency of the power system from the angular frequency, the frequency calculator further including a low-pass filter provided in series with the arithmetic

Abstract: A system frequency detector includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average. A frequency calculator calculates an angular frequency based on the two-phase voltage signal, and an arithmetic unit calculates a system frequency of the power system from the angular frequency.

Abstract: To provide a disc brake having a planetary gear reduction mechanism that may be satisfactory costly and achieve improved reliability, a planetary gear reduction mechanism of a disc brake according to the present disclosure includes a sun gear having an input gear portion to which rotation from a motor is transmitted and an output gear portion extending axially from a radial central region of the input gear portion, a plurality of planetary gears configured to mesh with the output gear portion of the sun gear, and an internal gear configured to mesh with each planetary gear, and the internal gear has a cylindrical support portion configured to rotatably support the sun gear. Accordingly, at the time of assembly, the axis of the sun gear and the axis of the internal gear may be arranged substantially concentrically, which may result in improved reliability and cost satisfaction.

Abstract: To provide a disc brake having a planetary gear reduction mechanism that may be satisfactory costly and achieve improved reliability, a planetary gear reduction mechanism of a disc brake according to the present disclosure includes a sun gear having an input gear portion to which rotation from a motor is transmitted and an output gear portion extending axially from a radial central region of the input gear portion, a plurality of planetary gears configured to mesh with the output gear portion of the sun gear, and an internal gear configured to mesh with each planetary gear, and the internal gear has a cylindrical support portion configured to rotatably support the sun gear. Accordingly, at the time of assembly, the axis of the sun gear and the axis of the internal gear may be arranged substantially concentrically, which may result in improved reliability and cost satisfaction.

Abstract: A process for producing 6-aminopenicillanic acid and 6-aminopenicillanic acid S-oxide by means of enzymes produced by microbes belonging to Arthrobacter genus, especially Arthrobacter cremorum and Arthrobacter flagellum.

Abstract: Penicillins and cephalosporins can be synthesized by the action of an acylase on a penicillin or cephalosporin nucleus amine as substrate and an ester (I) of the following formula as the acyl source: ##STR1## (wherein RCO is an acyl group in penicillin or cephalosporin side chains;X is a hydrogen atom, lower alkyl group or hydroxy-lower alkyl group;Y is a hydrogen atom or a lower alkyl group; and n is a positive integer).The novel acyl source (I) is also disclosed.

Abstract: Penicillin or cephalosporin antibiotics represented by following formula: ##STR1## where ##STR2## is an acyl group derived from an .alpha.-amino acid, N-ammonium salt of .alpha.-amino acid, or N--(C.sub.1 to C.sub.10) acyl-.alpha.-amino acid; COOM is carboxy or carboxylate salt group!Are prepared by treating an amino compound selected from a group consisting of 6-aminopenicillanic acid, 7-aminocephalosporanic acid, 7-aminodeacetoxycephalosporanic acid, and their salts with an ester represented by following formula:RCOOR.sup.1where ##STR3## is as defined above and R.sup.1 is a (C.sub.1 to C.sub.10) alkyl group! BY ENZYMATIC ACYLATION EFFECTED WITH MYCELIUM OR MYCELIUM PREPARATION FROM A MICROORGANISM BELONGING TO GENUS Aphanocladium or Cephalosporium.