Abstract: Due to a bimetallic contact point, a fine control is out of sight. Further, dispersion of bimetal characteristics and poor durability of a contact point cause problems, particularly in maintenance work. In order to overcome these problems, a controller for extending a service life of the contact point can provide a fine control, so that a maintenance-free electric cooker can be provided. The ON/OFF of the contact point of relay is controlled to operate at zero potential of commercial power, and a short-pulse-signal-switch that allows the relays to remove deposition by itself even if the contact point encounters deposition, are prepared and applied to plural heaters for controlling thereof.

Abstract: A relay control circuit enables releasing of welding of contacts in a short period by applying an bombardment pulse effective for welded contacts of the relay. Welded contacts of a relay are detected and subsequently input a signal to a microcomputer. A first driver is connected to an output port of the microcomputer which controls the relay, and a second driver is provided to another output port for driving the relay in parallel. This configuration allows to drive the first and second drivers alternately when contacts of the relay are welded, in order to apply an effective bombardment pulse for ensuring rapid separation of the welded contacts.

Abstract: A grinding method includes a grit sticking step and a grinding step. In the grit sticking step, grit particles are stuck in a first tool by contacting the first tool with a second tool which is harder than the first tool, rotating the first tool and the second tool, and feeding the grit to the contacting surface between the first tool and the second tool. In the grinding step, the workpiece is ground by contacting the first tool with the workpiece and rotating the first tool or the workpiece.

Abstract: Disclosed is a process for producing an epoxidized product of olefins, which comprises oxidizing olefins in the presence of an oxidizing catalyst, using an alcohol medium solution of hydrogen peroxide produced by catalytically reacting hydrogen with oxygen in an alcohol medium.According to the present invention, an epoxidized product of olefins can be produced by using an alcohol medium solution of hydrogen peroxide in high selectivity without requiring an aqueous hydrogen peroxide solution of high concentration and producing a large amount of by-products.

Abstract: A magnetic levitation transport system includes magnetic levitation vehicles each driven by a linear motor to run along a track. Induction lines extend through predetermined blocks of the running track to transmit a high frequency sine-wave current. Each vehicle includes electromagnets to attract levitating magnetic members extending along the running track, a pickup coil resonant with a frequency of the induction lines to generate an electromotive force, and a battery chargeable by the pickup coil. The electromagnets receive power from the pickup coil and/or the battery.

Abstract: An optical collimator having a collimator lens which is divided into front and rear collimator lenses. An inclined transparent parallel plate is located between the two collimator lenses, whereby the optical collimator is substantially free from comatic aberration and results in a collimator which can be reduced in size.