Abstract: Piezoelectric fibers include a polypeptide wherein molecules of the polypeptide have electric dipole moments that are aligned such that the piezoelectric fiber provides a piezoelectric effect at an operating temperature. A piezoelectric component provides a plurality of piezoelectric fibers, each comprising an organic polymer. A method of producing piezoelectric fibers includes electrospinning a polymer solution to form a fiber and winding the fiber onto a rotating target in which the rotating target is electrically grounded. An acoustic sensor includes a plurality acoustic transducers, wherein the plurality of acoustic transducers are structured and arranged to detect a corresponding plurality of vector components of an acoustic signal, and at least one of the plurality of acoustic transducers comprises a piezoelectric fiber.

Abstract: A sound sensor, a hydrophone including the sound sensor, and a pressure balancing device for using for the hydrophone are provided. The hydrophone includes: a sensor including a sensing part and a pressure balancing part; a printed circuit board (PCB) that is electrically connected to the sensor; a case that houses the sensor and the PCB and that has an opening at one side thereof; an elastic membrane that covers the opening of the case; and a signal line that is electrically connected to the PCB to be extended to the outside of the case. The pressure balancing part includes a diaphragm of a thin film and a support that supports the diaphragm. A pressure balancing hole is formed at one side of the pressure balancing part, and at the inside of the pressure balancing part, a channel that is connected to the pressure balancing hole is formed, and a compressible gas is filled in the channel.

Abstract: An area-variable type capacitive displacement sensor includes: a stationary element; a movable element; an elastic member for providing a force biasing one of the stationary element and the movable member towards a remaining one thereof in a direction perpendicular to a driving direction so that the stationary element and the movable member are maintained in close contact with each other; a power supply; and a signal detecting circuit. The sensor further includes a guide means for correcting an initial alignment error and reducing an operation alignment error between the stationary element and the movable element.

Abstract: A sound sensor, a hydrophone including the sound sensor, and a pressure balancing device for using for the hydrophone are provided. The hydrophone includes: a sensor including a sensing part and a pressure balancing part; a printed circuit board (PCB) that is electrically connected to the sensor; a case that houses the sensor and the PCB and that has an opening at one side thereof; an elastic membrane that covers the opening of the case; and a signal line that is electrically connected to the PCB to be extended to the outside of the case. The pressure balancing part includes a diaphragm of a thin film and a support that supports the diaphragm. A pressure balancing hole is formed at one side of the pressure balancing part, and at the inside of the pressure balancing part, a channel that is connected to the pressure balancing hole is formed, and a compressible gas is filled in the channel.

Abstract: Piezoelectric fibers include a polypeptide wherein molecules of the polypeptide have electric dipole moments that are aligned such that the piezoelectric fiber provides a piezoelectric effect at an operating temperature. A piezoelectric component provides a plurality of piezoelectric fibers, each comprising an organic polymer. A method of producing piezoelectric fibers includes electrospinning a polymer solution to form a fiber and winding the fiber onto a rotating target in which the rotating target is electrically grounded. An acoustic sensor includes a plurality acoustic transducers, wherein the plurality of acoustic transducers are structured and arranged to detect a corresponding plurality of vector components of an acoustic signal, and at least one of the plurality of acoustic transducers comprises a piezoelectric fiber.

Abstract: An area-variable type capacitive displacement sensor includes: a stationary element; a movable element; an elastic member for providing a force biasing one of the stationary element and the movable member towards a remaining one thereof in a direction perpendicular to a driving direction so that the stationary element and the movable member are maintained in close contact with each other; a power supply; and a signal detecting circuit. The sensor further includes a guide means for correcting an initial alignment error and reducing an operation alignment error between the stationary element and the movable element.

Abstract: A multiple resonances type ultrasonic transducer for a ranging measurement with high directionality using a parametric transmitting array in air, includes an ultrasonic actuator unit formed with a regularly mixing array of first unit actuators having a resonance frequency of f1 and second unit actuators having a resonance frequency of f2. The ultrasonic actuator unit generates a difference frequency wave (fd=f1?f2) with high directionality by forming a parametric transmitting array in air through generating two ultrasonic waves with high pressure in air. Further, the transducer includes an ultrasonic sensor unit formed with one or more unit sensors having a resonance frequency of the difference frequency (fd=f1?f2), for sensing a reflected ultrasonic pulse signal from a target.

Abstract: A probe of a scanning probe microscope having a sharp tip and an increased electric characteristic by fabricating a planar type of field effect transistor and manufacturing a conductive carbon nanotube on the planar type field effect transistor. To achieve this, the present invention provides a method for fabricating a probe having a field effect transistor channel structure including fabricating a field effect transistor, making preparations for growing a carbon nanotube at a top portion of a gate electrode of the field effect transistor, and generating the carbon nanotube at the top portion of the gate electrode of the field effect transistor.

Abstract: A contact-type electric capacitive displacement sensor includes a stationary element having a stationary plate, a stationary conductive pattern formed on the stationary plate and an insulation film coated on the stationary plate and a displaceable element having a displaceable plate, a displaceable conductive pattern formed on the displaceable plate and an insulation film coated on the displaceable plate. The stationary and the displaceable conductive patterns have a cyclic pattern of conductor to thereby produce a variation of capacitance therebetween when moving relative to each other.

Abstract: A multiple resonances type ultrasonic transducer for a ranging measurement with high directionality using a parametric transmitting array in air, includes an ultrasonic actuator unit formed with a regularly mixing array of first unit actuators having a resonance frequency of f1 and second unit actuators having a resonance frequency of f2. The ultrasonic actuator unit generates a difference frequency wave (fd=f1?f2) with high directionality by forming a parametric transmitting array in air through generating two ultrasonic waves with high pressure in air. Further, the transducer includes an ultrasonic sensor unit formed with one or more unit sensors having a resonance frequency of the difference frequency (fd=f1?f2), for sensing a reflected ultrasonic pulse'signal from a target.

Abstract: An ultrasonic ranging method for measuring a distance to an object in an air includes the steps of generating a first and a second primary ultrasonic waves having a frequency f1 and f2, respectively, transmitting the first and the second primary ultrasonic waves in a same direction, wherein a secondary ultrasonic wave having a frequency corresponding to the difference of two frequencies fd=f1?f2 is created by a nonlinear property of the air and radiated to the object, detecting an echo pulse of the secondary ultrasonic wave reflected from the object, and measuring the distance to the object based on a propagation time of the secondary wave.

Abstract: A contact-type electric capacitive displacement sensor includes a stationary element having a stationary plate, a stationary conductive pattern formed on the stationary plate and an insulation film coated on the stationary plate and a displaceable element having a displaceable plate, a displaceable conductive pattern formed on the displaceable plate and an insulation film coated on the displaceable plate. The stationary and the displaceable conductive patterns have a cyclic pattern of conductor to thereby produce a variation of capacitance therebetween when moving relative to each other.

Abstract: Disclosed is a probe of a scanning probe microscope having a sharp tip and an increased electric characteristic by fabricating a planar type of field effect transistor and manufacturing a conductive carbon nanotube on the planar type field effect transistor. To achieve this, the present invention provides a method for fabricating a probe having a field effect transistor channel structure including fabricating a field effect transistor, making preparations for growing a carbon nanotube at a top portion of a gate electrode of the field effect transistor, and generating the carbon nanotube at the top portion of the gate electrode of the field effect transistor.

Abstract: A capacitive motion sensor includes a primary plate including a primary pattern replicated periodically, a secondary plate including a plurality of pattern regions with an insulated region inserted there between, wherein each of the pattern regions has a secondary pattern replicated periodically, a signal source for sending a plate input signal to the primary plate, and a displacement measuring unit for receiving a plurality of plate output signals from the secondary plate to measure a displacement of a moving one of the plates with respect to the other one of the plates. The primary plate is arranged in parallel with the secondary plate in such a manner that the primary pattern is confronted with the secondary pattern and the pattern regions of the secondary plate are arranged in a two-dimensional array.

Abstract: An ultrasonic ranging method for measuring a distance to an object in an air includes the steps of generating a first and a second primary ultrasonic waves having a frequency f1 and f2, respectively, transmitting the first and the second primary ultrasonic waves in a same direction, wherein a secondary ultrasonic wave having a frequency corresponding to the difference of two frequencies fd=f1?f2 is created by a nonlinear property of the air and radiated to the object, detecting an echo pulse of the secondary ultrasonic wave reflected from the object, and measuring the distance to the object based on a propagation time of the secondary wave.

Abstract: A capacitive motion sensor includes a primary plate including a primary pattern replicated periodically, a secondary plate including a plurality of pattern regions with an insulated region inserted therebetween, wherein each of the pattern regions has a secondary pattern replicated periodically, a signal source for sending a plate input signal to the primary plate, and a displacement measuring unit for receiving a plurality of plate output signals from the secondary plate to measure a displacement of a moving one of the plates with respect to the other one of the plates.