A caliper pig for detecting geometrical deformation of a pipeline is disclosed. The caliper pig includes a body and a first sensor arm assembly. The first sensor arm assembly includes a primary caliper sensor ring adapted to be mounted on the body. Further, the first sensor arm assembly includes a plurality of sensor arms adapted circumferentially distributed on the primary caliper sensor ring. Each of the plurality of sensor arms includes a sensing arm adapted to be in contact with an internal surface of the pipeline and a pair of magnets adapted to rotate along the sensing arm. Each of the plurality of sensor arms includes a sensing unit configured to detect a change in magnetic field based on the movement of the sensing arm. The sensing unit is configured to generate an output indicative of an angle of deflection of the sensing arm while traversing on the internal surface of the pipeline.

The present disclosure discloses a magnetic flexible tactile sensor structure based on a folding magnetization method, which comprises a flexible body containing a permanent magnetic material; the flexible body has a negative Poisson's ratio structure, and its set area has undergone folding magnetization treatment. The present disclosure also discloses a sensor composed of the above-mentioned sensing structure. The sensor provided by the present disclosure can be applied in sealed and wireless scenarios. The present disclosure can detect the size and position of force. The flexible sensor has broad prospects in the application of the touch skin of robots. The function between the magnetic field-based sensing magnet and the Hall element is contactless. In some cases where it is difficult to establish isolation of the connection lines, it can also be used as an unfettered tactile sensor.

The present disclosure discloses a magnetic flexible tactile sensor structure based on a folding magnetization method, which comprises a flexible body containing a permanent magnetic material; the flexible body has a negative Poisson's ratio structure, and its set area has undergone folding magnetization treatment. The present disclosure also discloses a sensor composed of the above-mentioned sensing structure. The sensor provided by the present disclosure can be applied in sealed and wireless scenarios. The present disclosure can detect the size and position of force. The flexible sensor has broad prospects in the application of the touch skin of robots. The function between the magnetic field-based sensing magnet and the Hall element is contactless. In some cases where it is difficult to establish isolation of the connection lines, it can also be used as an unfettered tactile sensor.

Discussed is a secondary battery and a method for detecting lithium dendrite of the secondary battery. The secondary battery includes: a positive electrode and a negative electrode; a battery case configured to accommodate the positive electrode and the negative electrode; and a lithium dendrite detector provided at a tab of the positive electrode at a side of the battery case to detect lithium dendrite.

Discussed is a secondary battery and a method for detecting lithium dendrite of the secondary battery. The secondary battery includes: a positive electrode and a negative electrode; a battery case configured to accommodate the positive electrode and the negative electrode; and a lithium dendrite detector provided at a tab of the positive electrode at a side of the battery case to detect lithium dendrite.

A device has a flexible substrate supporting an array of magnetic sensors exposed to a uniform external magnetic field. One or more controllers receive magnetic sensor signals from the magnetic sensors. The one or more controllers collect reference magnetic sensor signals when the flexible substrate is aligned with the uniform external magnetic field. The one or more controllers collect first polarity magnetic sensor signals in response to deformation of the flexible substrate in a first direction. The one or more controllers collect second polarity magnetic sensor signals in response to deformation of the flexible substrate in a second direction. The magnetic sensor signals establish a profile of the orientation of the flexible substrate with respect to the uniform external magnetic field.

A device has a flexible substrate supporting an array of magnetic sensors exposed to a uniform external magnetic field. One or more controllers receive magnetic sensor signals from the magnetic sensors. The one or more controllers collect reference magnetic sensor signals when the flexible substrate is aligned with the uniform external magnetic field. The one or more controllers collect first polarity magnetic sensor signals in response to deformation of the flexible substrate in a first direction. The one or more controllers collect second polarity magnetic sensor signals in response to deformation of the flexible substrate in a second direction. The magnetic sensor signals establish a profile of the orientation of the flexible substrate with respect to the uniform external magnetic field.

A method for discovering, identifying, and monitoring of mechanical defects in a ferromagnetic underground or underwater structure. A magnetic scanner portable device is used to inspect the ferromagnetic underground structure and identify at least one portion with a magnetic field anomaly. Sets of permanent magnetic scanner sensors to monitor the magnetic field anomaly are placed adjacent to the at least one portion of the underground structure. A calculation unit, coupled to the sets of permanent magnetic scanner sensors is used to collect and process data. A stress-deformed state (SDS) and a risk-factor (RF) of the at least one portion with the magnetic field anomaly is presented on a display unit, which is coupled to the calculation unit.

A magneto acoustic emission detection method for fatigue damage of ferromagnetic metal components: First, generating an excitation magnetic field by using a sine wave voltage signal, gradually increasing a loading voltage until a magneto acoustic emission signal of a bimodal envelope with an obvious tail peak is acquired, and taking a corresponding voltage peak value as a reference voltage; second, generating an excitation magnetic field by using a square wave voltage signal equal to or higher than a reference voltage, and acquiring a magneto acoustic emission signal with a T-shaped envelope; and third, calculating the average value of peak-to-peak values of the magneto acoustic emission signal in multiple periods to serve as a characteristic parameter, and enabling the characteristic parameter to have inflection point change along with the development of the initiation and expansion of the fatigue crack, and giving a timely early warning for the failure of the component. ##STR00001##

A magneto acoustic emission detection method for fatigue damage of ferromagnetic metal components: First, generating an excitation magnetic field by using a sine wave voltage signal, gradually increasing a loading voltage until a magneto acoustic emission signal of a bimodal envelope with an obvious tail peak is acquired, and taking a corresponding voltage peak value as a reference voltage; second, generating an excitation magnetic field by using a square wave voltage signal equal to or higher than a reference voltage, and acquiring a magneto acoustic emission signal with a T-shaped envelope; and third, calculating the average value of peak-to-peak values of the magneto acoustic emission signal in multiple periods to serve as a characteristic parameter, and enabling the characteristic parameter to have inflection point change along with the development of the initiation and expansion of the fatigue crack, and giving a timely early warning for the failure of the component. ##STR00001##