Abstract: The subject of the present invention relates to obtaining a zirconia sintered body having excellent in both properties of a translucency and a mechanical strength. The present invention relates to obtaining a high-strength zirconia sintered body having a translucency of an in-line transmission of 50% or more at a sample thickness of 1 mm for visible light at a wavelength of 600 nm and an average flexural strength of 300 MPa or more by subjecting a zirconia primary sintered body having an average grain size of 1 ?m or less and a relative density of 92% or more and the crystal phase composed of cubic crystals only to HIP treatment at a temperature of 1,250° C. to 1,600° C. and a pressure of at least 50 MPa. The primary sintered body is obtained by maintaining a molded body of a zirconia powder containing 7 mol % to 30 mol % of yttria at 1,100° C. to 1,300° C. for at least 5 hrs or by heating the molded body at a high rate of temperature rise of 500° C./hr or more.

Abstract: The subject of the present invention relates to obtaining a zirconia sintered body having excellent in both properties of a translucency and a mechanical strength. The present invention relates to obtaining a high-strength zirconia sintered body having a translucency of an in-line transmission of 50% or more at a sample thickness of 1 mm for visible light at a wavelength of 600 nm and an average flexural strength of 300 MPa or more by subjecting a zirconia primary sintered body having an average grain size of 1 ?m or less and a relative density of 92% or more and the crystal phase composed of cubic crystals only to HIP treatment at a temperature of 1,250° C. to 1,600° C. and a pressure of at least 50 MPa. The primary sintered body is obtained by maintaining a molded body of a zirconia powder containing 7 mol % to 30 mol % of yttria at 1,100° C. to 1,300° C. for at least 5 hrs or by heating the molded body at a high rate of temperature rise of 500° C./hr or more.

Abstract: An abrasive molding comprising at least 90% by weight, based on the abrasive molding, of an inorganic material having a stock hardness of 50-400 kg/mm2, and said abrasive molding having a relative density of 20-70% and an average particle diameter of 0.001-50 &mgr;m. The abrasive molding preferably has pores having a pore size distribution such that the integrated pore volume of pores having a diameter of 0.01-1 &mgr;m is at least 20% of the integrated total pore volume of the entire pores, and the integrated pore volume of pores having a diameter of 1-360 &mgr;m is in the range of 10% to 70% of the integrated total pore volume of the entire pores. The abrasive molding is suitable for polishing a material having a Vickers hardness not larger than 300 kg/mm2.

Abstract: An abrasive molding comprising at least 90% by weight, based on the abrasive molding, of an inorganic material having a stock hardness of 50-400 kg/mm2, and said abrasive molding having a relative density of 20-70% and an average particle diameter of 0.001-50 &mgr;m. The abrasive molding preferably has pores having a pore size distribution such that the integrated pore volume of pores having a diameter of 0.01-1 &mgr;m is at least 20% of the integrated total pore volume of the entire pores, and the integrated pore volume of pores having a diameter of 1-360 &mgr;m is in the range of 10% to 70% of the integrated total pore volume of the entire pores. The abrasive molding is suitable for polishing a material having a Vickers hardness not larger than 300 kg/mm2.

Abstract: The present invention provides a waterproof plastic foam such as waterproof polyurethane foam which can keep the inherent properties of the foam and exhibit low gas permeability and water absorption, excellent water-sealing properties and hence a stable waterproofness.

Abstract: Disclosed is an electrically-operated fuel pump for pumping fuel such as gasoline, light oil and heavy oil, comprising a pump housing; a motor having a rotating shaft and encased centrally in the pump housing, the motor comprising a rotor formed by fixing a permanent magnet to the rotating shaft thereof and a stator arranged around the rotor, the stator having plural windings of coils adapted to be sequentially excited to rotate the rotor; a pump section encased in the pump housing below the motor and operatively connected to the rotating shaft of the motor; and an electric circuit package made of an oil-resistant and water-resistant material and incorporated in the pump housing above the motor, the electric circuit package oil-tightly incorporating a plurality of rotor position detecting devices for detecting an angular position of the rotor, wherein a portion of the electric circuit package facing to the rotor is made of a paramagnetic material.

Abstract: The safety circuit of the present invention is connected to a drive control circuit for applying driving signals to a plurality of switching devices connected to respective stator coils of the brushless D.C. motor at a predetermined timing, and sequentially supplying a driving current to each phase of the stator cells. The safety circuit is adapted to simultaneously detect the driving signals and generate a cut-off signal for cutting off the driving current supplied to each of the stator coils in the event that the driving signals are simultaneously applied to the switching devices in controlling a driving operation of the brushless D.C. motor.