Disclosed are method and apparatus for measuring material properties. Segmented field sensors have multiple sensing elements at different spatial geometries to capture field components having substantially different depths of penetration. These sensors are excited and measured on these different sensing elements to facilitate characterization of unknown material properties. This is illustrated in some embodiments using eddy current sensors to characterize materials that are frequency dispersive and/or do not produce a measurable phase shifts. Only a single scalar quantity may provide independent information from one or more of the sensing elements. Property estimation techniques, such as those using precomputed databases of sensor responses are used to estimate the unknown material properties.

Disclosed are method and apparatus for measuring material properties. Segmented field sensors have multiple sensing elements at different spatial geometries to capture field components having substantially different depths of penetration. These sensors are excited and measured on these different sensing elements to facilitate characterization of unknown material properties. This is illustrated in some embodiments using eddy current sensors to characterize materials that are frequency dispersive and/or do not produce a measurable phase shifts. Only a single scalar quantity may provide independent information from one or more of the sensing elements. Property estimation techniques, such as those using precomputed databases of sensor responses are used to estimate the unknown material properties.

The measurement device for measuring permeability and permittivity of an object, includes a probe in which a signal transmission line is formed and on which the object is capable of being disposed close to or in contact with the signal transmission line; a magnetic-field application unit configured to apply a magnetic-field to the object; a signal measurement instrument configured to measure a signal transmitted through the signal transmission line in each state in which the object is disposed and not disposed on the signal transmission line and in each state in which the magnetic-field is applied and not applied; a permeability processing unit configured to obtain the permeability of the object; and a permittivity processing unit configured to obtain the permittivity of the object, the both units obtaining based on the signal transmitted through the signal transmission line in each state in which the magnetic-field is applied and not applied.

The measurement device for measuring permeability and permittivity of an object, includes a probe in which a signal transmission line is formed and on which the object is capable of being disposed close to or in contact with the signal transmission line; a magnetic-field application unit configured to apply a magnetic-field to the object; a signal measurement instrument configured to measure a signal transmitted through the signal transmission line in each state in which the object is disposed and not disposed on the signal transmission line and in each state in which the magnetic-field is applied and not applied; a permeability processing unit configured to obtain the permeability of the object; and a permittivity processing unit configured to obtain the permittivity of the object, the both units obtaining based on the signal transmitted through the signal transmission line in each state in which the magnetic-field is applied and not applied.

The invention relates to a system comprising superparamagnetic or anhysteretic nanoparticles (NPs) functionalised with an antibody, and a thin-film-type substrate of metal or an oxide thereof, functionalised with the same antibody; and to a method for detecting a biological analyte, such as a cell, protein, microorganism or similar, preferably a pathogenic microorganism, and even more preferably Listeria. The method comprises: (a) obtaining a control signal from a substrate (magnetic or not) coated with a thin film of metal or an oxide thereof, preferably gold, which can be functionalised with an antibody, the control signal being a magnetoresistance signal, a total magnetisation signal or a signal of the magnetisation curve; (b) mixing superparamagnetic or anhysteretic NPs functionalised with the antibody, with a liquid sample to analyse and confirm the presence or absence of the biological analyte, the NPs and the liquid sample making contact for 10-90 minutes; (c) dripping the dispersion obtained in step (b) onto the substrate of step (a), and then washing to remove NPs that are not chemically anchored to the surface of the biological analyte; (d) leaving the substrate to dry and re-measuring a signal in the same way as carried out in step (a); and (e) counteracting the control signal obtained in step (a) and the signal obtained in step (d), and in the absence of differences between the two measurements, confirming the absence of the biological analyte in the sample, the amount of microorganisms being directly proportional to the signal measured.

The invention relates to a system comprising superparamagnetic or anhysteretic nanoparticles (NPs) functionalised with an antibody, and a thin-film-type substrate of metal or an oxide thereof, functionalised with the same antibody; and to a method for detecting a biological analyte, such as a cell, protein, microorganism or similar, preferably a pathogenic microorganism, and even more preferably Listeria. The method comprises: (a) obtaining a control signal from a substrate (magnetic or not) coated with a thin film of metal or an oxide thereof, preferably gold, which can be functionalised with an antibody, the control signal being a magnetoresistance signal, a total magnetisation signal or a signal of the magnetisation curve; (b) mixing superparamagnetic or anhysteretic NPs functionalised with the antibody, with a liquid sample to analyse and confirm the presence or absence of the biological analyte, the NPs and the liquid sample making contact for 10-90 minutes; (c) dripping the dispersion obtained in step (b) onto the substrate of step (a), and then washing to remove NPs that are not chemically anchored to the surface of the biological analyte; (d) leaving the substrate to dry and re-measuring a signal in the same way as carried out in step (a); and (e) counteracting the control signal obtained in step (a) and the signal obtained in step (d), and in the absence of differences between the two measurements, confirming the absence of the biological analyte in the sample, the amount of microorganisms being directly proportional to the signal measured.

The present invention discloses a 3D defect detection method with magnetic flux leakage testing (MFLT). It has advantages of higher accuracy of 3D detection of defect and simpler testing device relative to the prior MFLT art. This method includes the following steps: S1: artificially magnetizing a to-be-tested structure, and measuring its MFLT signals {B}; S2: inverting magnetic charge distribution of the interior of the to-be-tested structure by using a magnetic charge distribution reconstruction algorithm to obtain the magnetic charge density of a non-defective region of the to-be-tested structure; and S3: using the magnetic charge density of the non-defective region of the to-be-tested structure as a known constant, and conducting inverse iteration to reconstruct defect depth of the defective region to obtain a 3D image of the defective region of the to-be-tested structure.

The present invention discloses a 3D defect detection method with magnetic flux leakage testing (MFLT). It has advantages of higher accuracy of 3D detection of defect and simpler testing device relative to the prior MFLT art. This method includes the following steps: S1: artificially magnetizing a to-be-tested structure, and measuring its MFLT signals {B}; S2: inverting magnetic charge distribution of the interior of the to-be-tested structure by using a magnetic charge distribution reconstruction algorithm to obtain the magnetic charge density of a non-defective region of the to-be-tested structure; and S3: using the magnetic charge density of the non-defective region of the to-be-tested structure as a known constant, and conducting inverse iteration to reconstruct defect depth of the defective region to obtain a 3D image of the defective region of the to-be-tested structure.

Systems and methods are provided that facilitate high-sensitivity, carrier-resolved photo-Hall effect measurements. Majority and minority carrier properties can be measured and determined simultaneously. In one aspect, a system and method determine majority carrier type, density and mobility and, with modulated illumination, minority carrier mobility and photocarrier density. In another aspect, a system and method can determine hole and electron mobility, photocarrier density, absorbed photon density, recombination lifetime and diffusion length for hole, electron and ambipolar transport.

Systems and methods are provided that facilitate high-sensitivity, carrier-resolved photo-Hall effect measurements. Majority and minority carrier properties can be measured and determined simultaneously. In one aspect, a system and method determine majority carrier type, density and mobility and, with modulated illumination, minority carrier mobility and photocarrier density. In another aspect, a system and method can determine hole and electron mobility, photocarrier density, absorbed photon density, recombination lifetime and diffusion length for hole, electron and ambipolar transport.