Abstract: Provided are a flux-locked loop circuit, a flux-locked loop method and a superconducting quantum interference device (SQUID) measuring apparatus. The flux-locked loop circuit includes a pre-amplifier configured to amplify a signal output of a SQUID, an integrator configured to integrate a signal output from the pre-amplifier and output the integrated signal, an operating range expanding unit configured to initialize the integrator by comparing an output signal of the integrator with a positive or negative reference reset voltage corresponding to an external flux of a predetermined integral multiple of flux quantum, and a feedback circuit configured to supply current to eliminate a difference between the external flux applied to the SQUID and a magnetic flux corresponding to an integral multiple of the reference reset voltage according to the output signal of the integrator.

Abstract: A magnetoencephalography (MEG) measuring apparatus and an MEG measuring method. The MEG measuring apparatus includes a superconducting helmet having an inward brim, a sensor-equipped helmet disposed inside the superconducting helmet, a pick-up coil disposed inside the sensor-equipped helmet, and a superconducting quantum interference device (SQUID) sensor mounted on the sensor-equipped helmet and connected to the pick-up coil.

Abstract: The present invention relates to a shield apparatus and a shield method for measuring a subtle magnetic field. More specifically, the present invention relates to a shield apparatus having a precise magnetic sensor therein, for shielding an external magnetic field in a subtle magnetic field measurement apparatus including a magnetic field generation apparatus for exciting a sample, the shield apparatus for measuring a subtle magnetic field, including: a shield wall provided with a high-conductivity metal layer of high conductivity being partitioned into a plurality of segments and having a high-frequency shield property and a closed high-permeability soft magnetic layer spaced apart from the high-conductivity metal layer by a predetermined distance, so as to seal a measurement space.

Abstract: An apparatus and a method for indirectly cooling a superconducting quantum interference device (SQUID) are provided. The apparatus includes an outer container extending in a vertical direction; a metallic inner container inserted into the outer container to store a liquid coolant, the metal inner container including a top plate; a SQUID sensor module disposed between a bottom surface of the outer container and a bottom surface of the inner container; a heat transfer pillar adapted to cool the SQUID sensor module, the heat transfer pillar having one end connected to the bottom surface of the inner container and the other end directly or indirectly connected to the SQUID sensor module; a magnetic shield part formed of a superconductor covering a top surface of the SQUID sensor module; and a heat conduction plate being in thermal contact with the other end of the heat transfer pillar.

Abstract: Provided are a low-temperature cooling apparatus and a superconducting quantum interference device (SQUID) sensor module. The low-temperature cooling apparatus includes an outer container; an inner container disposed inside the outer container, the inner container including a neck portion having a first diameter and a body portion having a second diameter greater than the first diameter; an insert inserted into the neck portion of the inner container; and a plurality of SQUID sensor modules inserted into the body portion of the inner container. Each of the SQUID sensor modules is in the form of a fan-shaped pillar and is fixedly coupled with an inner bottom plate of the inner container.

Abstract: Provided are an ultra-low-field nuclear magnetic resonance device and an ultra-low-field nuclear magnetic resonance measuring method. The method includes applying a first measurement bias magnetic field corresponding to an excitation frequency of a coherent biomagnetic field generated in association with the electrophysiological activity of human body organs, applying a second measurement bias magnetic field having the same direction as the first measurement bias magnetic field and having a different magnitude than the first measurement bias magnetic field, and measuring a magnetic resonance signal generated in the human body by using magnetic field measuring means.

Abstract: A method for mapping of myocardial electric activity includes measuring electrocardiogram data or magnetocardiogram data and mapping the degree of electric activity of a myocardial surface using the electrocardiogram data or the magnetocardiogram data. A signal source of the electrocardiogram data or the magnetocardiogram data is a myocardial surface potential that is scalar quantity. The mapping uses a lead-field vector which represents the sensitivity between the myocardial surface potential and the electrocardiogram or magnetocardiogram data, and a modified lead-field vector which combines a constraint matrix with a constraint condition where no potential sources exist in a specific region.

Abstract: Provided are an object discrimination method and an object discrimination apparatus using an ultra-low magnetic field nuclear magnetic resonance (NMR). The method includes measuring the respective spin-lattice relaxation times at a plurality of strengths of prepolarization magnetic fields with respect to a measurement target and classifying the measurement target using the spin-lattice relaxation times.

Abstract: A system for acquiring data of a multi-channel superconducting quantum interference device (SQUID) signal includes a digital converter connected to a SQUID sensor having a plurality of channels and configured to receive a voltage signal output from the plurality of channels and generate a channel-voltage serial digital signal having information about a channel from which the voltage signal is output and information about the voltage signal, and an optical fiber cable through which the channel-voltage serial digital signal is transmitted from the digital converter.

Abstract: Provided are an apparatus and a method for canceling magnetic fields. The apparatus includes a magnetic field canceling coil disposed adjacent to an inner wall of a magnetic shield room to surround the entire inner space or a portion of an inner space of the magnetic shield room; and a magnetic field canceling coil driver to supply current to the magnetic field canceling coil. The magnetic field canceling coil cancels a prepolarization magnetic field established on the wall of the magnetic shield room by a prepolarization coil disposed in the center of the magnetic shield room to minimize magnetic interference caused by the magnetic shield room.

Abstract: A nuclear magnetic resonance apparatus includes a dewar containing a low-temperature liquid refrigerant, a prepolarization coil disposed inside the dewar and including a superconducting wire, a prepolarization coil driving unit for intermittent application of current to the prepolarization coil in a capacitor charge/discharge method to generate a prepolarization magnetic field, a sensor unit for measuring a nuclear magnetic resonance signal from a sample to which a prepolarization magnetic field is applied with the prepolarization coil, and a readout magnetic field generation unit for applying a readout magnetic field to the sample.

Abstract: Provided are a flux-locked loop circuit, a flux-locked loop method and a superconducting quantum interference device (SQUID) measuring apparatus. The flux-locked loop circuit includes a pre-amplifier configured to amplify a signal output of a SQUID, an integrator configured to integrate a signal output from the pre-amplifier and output the integrated signal, an operating range expanding unit configured to initialize the integrator by comparing an output signal of the integrator with a positive or negative reference reset voltage corresponding to an external flux of a predetermined integral multiple of flux quantum, and a feedback circuit configured to supply current to eliminate a difference between the external flux applied to the SQUID and a magnetic flux corresponding to an integral multiple of the reference reset voltage according to the output signal of the integrator.

Abstract: A system for acquiring data of a multi-channel superconducting quantum interference device (SQUID) signal includes a digital converter connected to a SQUID sensor having a plurality of channels and configured to receive a voltage signal output from the plurality of channels and generate a channel-voltage serial digital signal having information about a channel from which the voltage signal is output and information about the voltage signal, and an optical fiber cable through which the channel-voltage serial digital signal is transmitted from the digital converter.

Abstract: A nuclear magnetic resonance apparatus includes a dewar containing a low-temperature liquid refrigerant, a prepolarization coil disposed inside the dewar and including a superconducting wire, a prepolarization coil driving unit for intermittent application of current to the prepolarization coil in a capacitor charge/discharge method to generate a prepolarization magnetic field, a sensor unit for measuring a nuclear magnetic resonance signal from a sample to which a prepolarization magnetic field is applied with the prepolarization coil, and a readout magnetic field generation unit for applying a readout magnetic field to the sample.