Abstract: A piezoelectric single crystal ingot is produced by the Bridgman method and contains a relaxor having a composition of Pb(Mg, Nb)O3 and lead titanate having a composition of PbTiO3. In the piezoelectric single crystal ingot, the compositional fraction of lead titanate does not vary monotonically in the growth direction of a single crystal and the variation of the compositional fraction thereof is within the range of ±2.0 mole percent over a length of 30 mm or more. A piezoelectric single crystal device is produced from the piezoelectric single crystal ingot.

Abstract: A piezoelectric single crystal ingot is produced by the Bridgman method and contains a relaxor having a composition of Pb(Mg, Nb)O3 and lead titanate having a composition of PbTiO3. In the piezoelectric single crystal ingot, the compositional fraction of lead titanate does not vary monotonically in the growth direction of a single crystal and the variation of the compositional fraction thereof is within the range of ±2.0 mole percent over a length of 30 mm or more. A piezoelectric single crystal device is produced from the piezoelectric single crystal ingot.

Abstract: In a piezoelectric device that uses a vibration mode in a direction parallel to a polarization direction, a single crystal device that achieves an electromechanical coupling factor of 65% or more, which is more than the electromechanical coupling factor (about 60%) of the existing flat plane type piezoelectric single crystal device in that vibrational direction, is provided by performing certain treatment to its device plane. Specifically, a piezoelectric portion having a comb-shaped structure in which a plurality of slits are formed with a certain arrangement pitch on either of device planes whose polarization direction is their normal direction, the slits having a depth extending in a direction substantially perpendicular to the device plane and being filled with an insulating material, is formed to achieve 65% or more of an electromechanical coupling factor in a direction parallel to the polarization direction.

Abstract: The present invention provides a piezoelectric single crystal device excellent in heat resistance and capable of stably maintaining the electromechanical coupling factor k31 in a lateral vibration mode at a high value of 50% or more without a decrease even in an operating environment in which the temperature changes from room temperature to a high temperature (specifically, 150° C.), and also provides a fabrication method thereof. Specifically, assuming that the [101] axis of a tetragonal system having the [001] axis as a C axis (with the largest lattice constant) is a polarization direction 3, a normal direction 1 to an edge face T of the piezoelectric device is within the solid-angle range of ±25° with respect to the [-101] axis substantially orthogonal to the polarization direction 3, the range including the [-101] axis.

Abstract: In a piezoelectric device that uses a vibration mode in a direction parallel to a polarization direction, a single crystal device that achieves an electromechanical coupling factor of 65% or more, which is more than the electromechanical coupling factor (about 60%) of the existing flat plane type piezoelectric single crystal device in that vibrational direction, is provided by performing certain treatment to its device plane. Specifically, a piezoelectric portion having a comb-shaped structure in which a plurality of slits are formed with a certain arrangement pitch on either of device planes whose polarization direction is their normal direction, the slits having a depth extending in a direction substantially perpendicular to the device plane and being filled with an insulating material, is formed to achieve 65% or more of an electromechanical coupling factor in a direction parallel to the polarization direction.

Abstract: The present invention provides a piezoelectric single crystal device excellent in heat resistance and capable of stably maintaining the electromechanical coupling factor k31 in a lateral vibration mode at a high value of 50% or more without a decrease even in an operating environment in which the temperature changes from room temperature to a high temperature (specifically, 150° C.), and also provides a fabrication method thereof. Specifically, assuming that the [010] axis of a tetragonal system having the [001] axis as a C axis (with the largest lattice constant) is a polarization direction 3, a normal direction 1 to an edge face T of the piezoelectric device is within the solid-angle range of ±25° with respect to the [-101] axis substantially orthogonal to the polarization direction 3, the range including the [-101] axis.

Abstract: To provide a piezoelectric single-crystal device which can stably attain an electromechanical coupling factor k31 of 60% or more in the lateral vibration mode and a method of manufacturing the same. Specifically, the piezoelectric single-crystal device has the polarization direction 3 in the [110] axis of a pseudocubic system and has the direction normal to an end face 10c of the piezoelectric device within the solid angle range of the [001] axis ±35° including the [001] axis approximately orthogonal to the polarization direction 3. The electromechanical coupling factor k31 in the direction orthogonal to the polarization direction 3, in the so-called lateral vibration mode, is 60% or more.

Abstract: An inexpensive piezoelectric single-crystal device being excellent in the piezoelectric characteristics and having a complex perovskite structure can be provided by adding a specific additive to a lead magnesium niobate-lead titanate (PMN-PT) single crystal or a lead zinc niobate-lead titanate (PZN-PT or PZNT) single crystal. Specifically, the piezoelectric single crystal has a complex perovskite structure and is formed of a composition containing 35 to 98 mol % lead magnesium niobate [Pb(Mg1/3Nb2/3)O3] or lead zinc niobate [Pb(Zn1/3Nb2/3)O3], 0.1 to 64.9 mol % lead titanate [PbTiO3], and 0.05 to 30 mol % lead indium niobate [Pb(In1/2Nb1/2)O3] wherein calcium is substituted for 0.05 to 10 mol % lead in the composition.

Abstract: A piezoelectric single crystal device is provided exhibiting excellent piezoelectric properties, within a specific high-temperature range of Trrt° C. to (Trt?20)° C., where Trt represents a transformation temperature between a pseudocubic system and a tetragonal system. Specifically, the piezoelectric single crystal device is composed of a single crystal having a composition represented by [Pb(Mg,Nb)O3](1-X)·[PbTiO3](X), where X is within the range of 0.26 to 0.29 and having a complex perovskite structure, wherein a specific inductive capacity at 25° C. is 5,000 or more, and a specific inductive capacity at the transformation temperature between a pseudocubic system and a tetragonal system of the above-described single crystal is 2.5 times or more larger than the specific inductive capacity at 25° C.

Abstract: An inexpensive piezoelectric single-crystal device being excellent in the piezoelectric characteristics and having a complex perovskite structure can be provided by adding a specific additive to a lead magnesium niobate-lead titanate (PMN-PT) single crystal or a lead zinc niobate-lead titanate (PZN-PT or PZNT) single crystal. Specifically, the piezoelectric single crystal has a complex perovskite structure and is formed of a composition containing 35 to 98 mol % lead magnesium niobate [Pb(Mg1/3Nb2/3)O3] or lead zinc niobate [Pb(Zn1/3Nb2/3)O3], 0.1 to 64.9 mol % lead titanate [PbTiO3], and 0.05 to 30 mol % lead indium niobate [Pb(In1/2Nb1/2)O3] wherein calcium is substituted for 0.05 to 10 mol % lead in the composition.

Abstract: To provide a piezoelectric single-crystal device which can stably attain an electromechanical coupling factor k31 of 60% or more in the lateral vibration mode and a method of manufacturing the same. Specifically, the piezoelectric single-crystal device has the polarization direction 3 in the [110] axis of a pseudocubic system and has the direction normal to an end face 10c of the piezoelectric device within the solid angle range of the [001] axis ±35° including the [001] axis approximately orthogonal to the polarization direction 3. The electromechanical coupling factor k31 in the direction orthogonal to the polarization direction 3, in the so-called lateral vibration mode, is 60% or more.

Abstract: A piezoelectric single crystal device is provided exhibiting excellent piezoelectric properties, within a specific high-temperature range of Trrt° C. to (Trt?20)° C., where Trt represents a transformation temperature between a pseudocubic system and a tetragonal system. Specifically, the piezoelectric single crystal device is composed of a single crystal having a composition represented by [Pb(Mg,Nb)O3](1?X)·[PbTiO3](X), where X is within the range of 0.26 to 0.29 and having a complex perovskite structure, wherein a specific inductive capacity at 25° C. is 5,000 or more, and a specific inductive capacity at the transformation temperature between a pseudocubic system and a tetragonal system of the above-described single crystal is 2.5 times or more larger than the specific inductive capacity at 25° C.

Abstract: A piezoelectric single crystal device for actively employing the electromechanical coupling factor k31 in the direction orthogonal to the polarization direction is provided. Specifically, with the polarization direction as [001] axis of a pseudocubic system, an angle between the normal direction 1 of the piezoelectric device edge face and the direction n orthogonal to the domain structure within the crystal face including [010] and [100] axes orthogonal to the polarization direction is in the range 0 to 15° or 40 to 50°.

Abstract: A piezoelectric single crystal device for actively employing the electromechanical coupling factor k31 in the direction orthogonal to the polarization direction is provided. Specifically, with the polarization direction as [001] axis of a pseudocubic system, an angle between the normal direction 1 of the piezoelectric device edge face and the direction n orthogonal to the domain structure within the crystal face including [010] and [100] axes orthogonal to the polarization direction is in the range 0 to 15° or 40 to 50°.

Abstract: A domain controlled piezoelectnc single crystal is disclosed which uses a lateral vibration mode for an electromechanical coupling factor k31 not less than 70% and a piezoelectric constant −d31 not less than 1200 pC/N, with an electromechanical coupling factor k33 in the longitudinal vibration mode not less than 80% and a piezoelectric constant d33 not less than 800 pC/N. Also, a piezoelectric single crystal is disclosed which uses a high-performance longitudinal vibration mode with k31 not more than 30%. A fabrication method applies a DC electric field of 400 V/mm to 1500 V/mm for a maximum of two hours in a temperature range of 20° C. to 200° C. as polarization conditions in the thickness direction of the piezoelectric single crystal. The method can include cooling, or heating and cooling between temperature boundaries of rhombohedral and tetragonal crystals or between tetragonal and cubic crystals or within a cubic crystal temperature range.

Abstract: A domain controlled piezoelectric single crystal is disclosed which uses a lateral vibration mode for an electromechanical coupling factor k31 not less than 70% and a piezoelectric constant −d31 not less than 1200 pC/N, with an electromechanical coupling factor k33 in the longitudinal vibration mode not less than 80% and a piezoelectric constant d33 not less than 800 pC/N. Also, a piezoelectric single crystal is disclosed which uses a high-performance longitudinal vibration mode with k31 not more than 30%. A fabrication method applies a DC electric field of 400 V/mm to 1500 V/mm for a maximum of two hours in a temperature range of 20° C. to 200° C. as polarization conditions in the thickness direction of the piezoelectric single crystal. The method can include cooling, or heating and cooling between temperature boundaries of rhombohedral and tetragonal crystals or between tetragonal and cubic crystals or within a cubic crystal temperature range.

Abstract: A noncontact mechanical seal has a seal ring which includes a sealing face portion formed by ventilative porous materials and a ventilating portion to pass a gas of a high pressure side to the sealing face portion from the back side of said sealing face portion. The sealing face portion is preferably a porous ring independently formed of said seal ring and mounted on the seal ring providing a space at the back side thereof. The seal ring preferably is provided with a small diameter thin portion at the portion forming the bottom of the space.

Abstract: A mechanial seal having a split seal ring which is covered by a support ring over the outer face with a predetermined gap and is fastened in a circular shape by a O ring inserted in the predetermined gap. The split seal ring is easily assembled by a tool which includes a split ring body. The split ring body has a basic inner face contacting to a surface of a rotary shaft, an end face contacting to the end face of the split seal ring an a projection for inserting the O ring into the gap.

Abstract: The present invention relates to a fluid agitator which may stir fluid in a closed space without leakage of the fluid. The fluid agitator has a motive means and a bearing means installed in the closed space. In the fluid agitator employing a electric motor as the motive means, only the stator coil of the motor which is weak in its resistance against high temperatures and humid atmosphere is sealed in a sealing chamber. The sealing chamber may be provided with a cooling device to cool the inside thereof. The driving shaft of the motor is supported by a bearing having resistance to high temperatures and high humidity and is provided with an agitating blade. In the fluid agitator employing a turbine system as the motive means, a turbine chamber and a turbine blade are set in the closed space. A fluid supply is furnished to introduce fluid into the turbine chamber from outside of the closed space for driving and rotating the turbine blade.

Abstract: A mechanical seal is, at a sliding surface and at its vicinty, formed of a pore-dispersed cemented carbide, so that the lubricating characteristics can be improved and the strength maintained by strictly stipulating the magnitude, shape, and volumetric ratio of the pores, such that pores are contained in an amount of 0.5 to 20 volume %, formed in at least one shape selected from the group of a substantialy spherical shape and a substantially cylindrical shape, the pores in the substantially spherical shape having an average diameter of 3 to 20 .mu.m, the pores in the substantially cylindrical shape having an average diameter of 3 to 20 .mu.m and an average length in the range from the average diameter up to 300 .mu.m, and that the pores are prevented from linking to each other to give a length greater than 2 mm.