Abstract: A continuous polymerization method for laurolactam which has three stages. A prepolymerization process include steps of preliminarily heating laurolactam with 1 to 10% weight of water added, thereafter continuously feeding and passing the laurolactam from the upper part of the lower part of the longitudinal-type polymerization reaction zone, arranging a temperature decreasing gradient of 10.degree. C. or more than the upper part to the lower part directions at a polymerization temperature of 250.degree. and 300.degree. C. in the polymerization zone, and polymerizing the laurolactam under vapor pressure up to a conversion rate of 99.5% or more. A intermediate process has a step of releasing pressure from the prepolymerization product from the prepolymerization process for conversion into an intermediate product at atmospheric pressure.

Abstract: A continuous polymerization method for laurolactam which has three stages. A prepolymerization process include steps of preliminarily heating laurolactam with 1 to 10% weight of water added, thereafter continuously feeding and passing the laurolactam from the upper part of the lower part of the longitudinal-type polymerization reaction zone, arranging a temperature decreasing gradient of 10.degree. C. or more than the upper part to the lower part directions at a polymerization temperature of 250.degree. and 300.degree. C. in the polymerization zone, and polymerizing the laurolactam under vapor pressure up to a conversion rate of 99.5% or more. A intermediate process has a step of releasing pressure from the prepolymerization product from the prepolymerization process for conversion into an intermediate product at atmospheric pressure.

Abstract: A magnetically floating carrier system has a carriage body which is adapted to be floated by the attraction force of floating magnets acting upon the bottom surfaces of rails. The carriage body is driven by a linear motor. The rails are mounted on a framework extending longitudinally to define a track and having one side thereof supported. The carriage body is provided with a support member extending upwards at the other side of the framework to a point above the top surfaces of the framework. A pallet for supporting a load is mounted on the top end of the support member so as to be disposed over the framework. The carriage carries four magnets at front and rear parts thereof which are adapted to exert a force of attraction on the pair of rails. The magnets are mounted at both ends of two beams mounted on front and rear parts of the carriage body for see-saw motions and steering motions.

Abstract: According to the present invention, control is performed to set a constant difference between two phase inputs among three phase inputs to a three-phase brushless motor. As a result, imbalance between the respective phase inputs (signals) is eliminated, thus performing motor control with good rotational precision. According to the present invention, amplifiers (1.sub.1 -1.sub.3, 2.sub.1 -2.sub.3, 3.sub.1 -3.sub.3) for receiving rotor position detection signals of the motor are provided in common to the three-phase input lines of the three-phase brushless motor. One of the difference and the sum of a product of two phases signals, among three phase outputs from these amplifiers, and a signal as the square of the remaining phase signal is compared with a constant value. A comparison result signal is fed back to the amplifiers (1.sub.1 -1.sub.3, or 2.sub.1 -2.sub.3, or 3.sub.1 -3.sub.3) of a common stage of the three-phase input lines to control the rotation of the motor.

Abstract: A motor-controlling apparatus is disclosed, wherein the signal generated by the Hall element located near the rotor of a motor is amplified twice, first by an input amplifier and then by an output amplifier, thus producing two drive pulse signals which are out of phase and having a 180.degree. duration. These signals are supplied to the motor coils of the motor and also to comparators connected at the output. The output currents of the comparators are thus combined, forming an output current, which is delayed and then converted into a voltage. This voltage is applied to the inverting input terminal of a two-input amplifier constituting a feedback circuit. A constant voltage is applied to the non-inverting input terminal of the two-input amplifier. The two-input amplifier generates a bias current, which is fed back to the output amplifier, thereby reducing the changes in the speed of rotation of the motor which result from the variation of the load on the motor.

Abstract: A resin composition comprising;100 parts by weight of a mixture comprising (a) from 5 to 95% by weight of polyamide and (b) from 95 to 5% by weight of a thermoplastic polyester; and(c) from 0.5 part to 40 parts by weight of a grafted polyolefin modified product formed by graft polymerization of an addition polymer having a peroxy bond in its molecular chain to a modified polyolefin having a functional group in its molecular chain; and a molded product thereof.

Abstract: Disclosed is a method for etching a polyamide shaped article which comprises etching a polyamide shaped article formed from a composition comprising 100 parts by weight of a polyamide and 10 to 50 parts by weight of an inorganic filler with an aqueous solution of borofluoric acid.According to this treating method, a good surface capable of providing a plated article having a high adhesion and a reduced deviation of the adhesion can be formed on the polyamide shaped article.