Systems, methods and piezoelectric patches are provided for monitoring the structural health of connectors in overhead transmission lines. A plurality of piezoelectric patches is mounted to different locations on the connector. At least one of the patches is actuated using an AC voltage and certain electrical properties either from the same patch or of a different patch are evaluated over time to determine the structural health of the connectors.

A method of calibrating a coefficient of a pressure sensor for blasting operations, including striking a first piezoelectric sensor of a first unmolded pressure sensing apparatus; determining, with an interface circuit, a first peak voltage of the first piezoelectric sensor during the striking thereof, striking a second piezoelectric sensor of a second molded pressure sensing apparatus; determining with the interface circuit, a second peak voltage of the second piezoelectric sensor during the striking thereof, and calculating a piezoelectric constant of the second piezoelectric from at least the first and second peak voltages.

A method of calibrating a coefficient of a pressure sensor for blasting operations, including striking a first piezoelectric sensor of a first unmolded pressure sensing apparatus; determining, with an interface circuit, a first peak voltage of the first piezoelectric sensor during the striking thereof, striking a second piezoelectric sensor of a second molded pressure sensing apparatus; determining with the interface circuit, a second peak voltage of the second piezoelectric sensor during the striking thereof, and calculating a piezoelectric constant of the second piezoelectric from at least the first and second peak voltages.

Current flow monitoring, from which a power dissipation metric in a load circuit may be obtained, is often performed using a current sense resistor. However, this implies extra circuit complexity. This application discusses a way to derive an indication of power consumption in a situation where an efficient load, is present, without the use of a current sense resistor, or the associated electronics. A nebulizer is an example of a device used for providing a medicament to a patient via their respiratory tract. A nebulizer typically comprises a reservoir for storing the medicament, in fluid communication with a means for converting the medicament to an aerosol. Knowledge of the power dissipation of such devices is useful.

A crystal unit includes: a crystal blank; an excitation electrode formed on the crystal blank and excites a main vibration of the crystal blank; a housing that accommodates the crystal blank; and a sub-vibration electrode formed on the housing and excites a sub-vibration of the crystal blank.

And a method for inspecting a crystal unit, the method includes: generating a sub-vibration in a crystal blank by applying an input signal to a sub-vibration electrode formed on a housing, which accommodates the crystal blank, via external electrodes which are electrically coupled to the sub-vibration electrode and formed on the outer surface of the housing; obtaining an output of the crystal unit via the external electrodes; obtaining frequency characteristics of impedance between the external electrodes based on the output; and comparing the obtained frequency characteristics with the reference frequency characteristics indicating the quality of the crystal unit.

A crystal unit includes: a crystal blank; an excitation electrode formed on the crystal blank and excites a main vibration of the crystal blank; a housing that accommodates the crystal blank; and a sub-vibration electrode formed on the housing and excites a sub-vibration of the crystal blank.

And a method for inspecting a crystal unit, the method includes: generating a sub-vibration in a crystal blank by applying an input signal to a sub-vibration electrode formed on a housing, which accommodates the crystal blank, via external electrodes which are electrically coupled to the sub-vibration electrode and formed on the outer surface of the housing; obtaining an output of the crystal unit via the external electrodes; obtaining frequency characteristics of impedance between the external electrodes based on the output; and comparing the obtained frequency characteristics with the reference frequency characteristics indicating the quality of the crystal unit.

A thermal poling method in which a poling treatment can be performed easily by a dry process. The poling treatment is performed on a PZT film by performing a heat treatment on the PZT film under a pressurized oxygen atmosphere at a temperature of 400 C. or more and 900 C. or less. The PZT film before the heat treatment has a single-domain crystal structure, and the PZT film after the heat treatment has a multi-domain crystal structure.

A thermal poling method in which a poling treatment can be performed easily by a dry process. The poling treatment is performed on a PZT film by performing a heat treatment on the PZT film under a pressurized oxygen atmosphere at a temperature of 400 C. or more and 900 C. or less. The PZT film before the heat treatment has a single-domain crystal structure, and the PZT film after the heat treatment has a multi-domain crystal structure.

A crystal unit includes: a crystal blank; an excitation electrode formed on the crystal blank and excites a main vibration of the crystal blank; a housing that accommodates the crystal blank; and a sub-vibration electrode formed on the housing and excites a sub-vibration of the crystal blank. And a method for inspecting a crystal unit, the method includes: generating a sub-vibration in a crystal blank by applying an input signal to a sub-vibration electrode formed on a housing, which accommodates the crystal blank, via external electrodes which are electrically coupled to the sub-vibration electrode and formed on the outer surface of the housing; obtaining an output of the crystal unit via the external electrodes; obtaining frequency characteristics of impedance between the external electrodes based on the output; and comparing the obtained frequency characteristics with the reference frequency characteristics indicating the quality of the crystal unit.

A crystal unit includes: a crystal blank; an excitation electrode formed on the crystal blank and excites a main vibration of the crystal blank; a housing that accommodates the crystal blank; and a sub-vibration electrode formed on the housing and excites a sub-vibration of the crystal blank. And a method for inspecting a crystal unit, the method includes: generating a sub-vibration in a crystal blank by applying an input signal to a sub-vibration electrode formed on a housing, which accommodates the crystal blank, via external electrodes which are electrically coupled to the sub-vibration electrode and formed on the outer surface of the housing; obtaining an output of the crystal unit via the external electrodes; obtaining frequency characteristics of impedance between the external electrodes based on the output; and comparing the obtained frequency characteristics with the reference frequency characteristics indicating the quality of the crystal unit.