An acoustically driven ferromagnetic resonance (ADFMR) device includes a piezoelectric element, a pair of transducers arranged to activate the piezoelectric element to generate an acoustic wave, a magnetostrictive element arranged to receive the acoustic wave, and a readout circuit to detect one of either a change in the magnetostrictive element or a change in the acoustic wave.

There is provided a method and system for identifying the location of an obstruction in a pipeline comprising: sensing the magnetic field generated by a pipeline at an initial pressure from a first location along the length of the pipeline to obtain a baseline reading; altering the pressure from a first end until a maximum pressure or minimum pressure is attained; sensing the magnetic field at the maximum or minimum pressure from the first location to obtain a stress reading; and identifying the location of the obstruction as a) being between a second end and the first location when there is a deviation between the stress reading and the baseline reading at the first location or as b) being between the first end and the first location when there is an absence of a deviation between the stress reading and the baseline reading at the first location.

There is provided a method and system for identifying the location of an obstruction in a pipeline comprising: sensing the magnetic field generated by a pipeline at an initial pressure from a first location along the length of the pipeline to obtain a baseline reading; altering the pressure from a first end until a maximum pressure or minimum pressure is attained; sensing the magnetic field at the maximum or minimum pressure from the first location to obtain a stress reading; and identifying the location of the obstruction as a) being between a second end and the first location when there is a deviation between the stress reading and the baseline reading at the first location or as b) being between the first end and the first location when there is an absence of a deviation between the stress reading and the baseline reading at the first location.

Provided is a method for manufacturing a grain-oriented electrical steel sheet. The method comprises: hot rolling a slab to obtain a hot rolled sheet; subjecting the hot rolled sheet to hot band annealing as necessary; subjecting the hot rolled sheet to cold rolling; subjecting the cold rolled sheet to decarburization annealing; applying an annealing separator having MgO as a main component onto a surface of the decarburization annealed sheet and subjecting the decarburization annealed sheet to final annealing to form the forsterite film; and applying an insulating coating treatment liquid onto the final annealed sheet and subjecting the final annealed sheet to flattening annealing to form a tension-applying insulating coating. A difference in total tensions between one and opposite surfaces of the sheet is less than 0.5 MPa. A difference in tensions between the forsterite films in one and opposite surfaces of the sheet is 0.5 MPa or more.

Provided is a method for manufacturing a grain-oriented electrical steel sheet. The method comprises: hot rolling a slab to obtain a hot rolled sheet; subjecting the hot rolled sheet to hot band annealing as necessary; subjecting the hot rolled sheet to cold rolling; subjecting the cold rolled sheet to decarburization annealing; applying an annealing separator having MgO as a main component onto a surface of the decarburization annealed sheet and subjecting the decarburization annealed sheet to final annealing to form the forsterite film; and applying an insulating coating treatment liquid onto the final annealed sheet and subjecting the final annealed sheet to flattening annealing to form a tension-applying insulating coating. A difference in total tensions between one and opposite surfaces of the sheet is less than 0.5 MPa. A difference in tensions between the forsterite films in one and opposite surfaces of the sheet is 0.5 MPa or more.

A magnetic field sensor element with a piezo electric substrate having predetermined shear wave velocity V.sub.S, two pairs of interdigital electrodes, arranged on the substrate on the ends of a delay section, having a period length p of at least 10 micrometers, a non-magnetic, electrically non-conductive guide layer arranged on the substrate along the delay section, and a magnetostrictive functional layer arranged on the guide layer, wherein the shear wave velocity in the guide layer is smaller than V.sub.S, wherein a) the substrate is oriented to generate and propagate mechanical shear waves upon applying a temporally periodic, electrical voltage to at least one interdigital electrode pair in the range of frequency V.sub.S/p and, wherein b) the thickness of the guide layer equals at least 10% and at most 30% of the period length p of the interdigital electrodes.

A magnetic field sensor element with a piezo electric substrate having predetermined shear wave velocity V.sub.S, two pairs of interdigital electrodes, arranged on the substrate on the ends of a delay section, having a period length p of at least 10 micrometers, a non-magnetic, electrically non-conductive guide layer arranged on the substrate along the delay section, and a magnetostrictive functional layer arranged on the guide layer, wherein the shear wave velocity in the guide layer is smaller than V.sub.S, wherein a) the substrate is oriented to generate and propagate mechanical shear waves upon applying a temporally periodic, electrical voltage to at least one interdigital electrode pair in the range of frequency V.sub.S/p and, wherein b) the thickness of the guide layer equals at least 10% and at most 30% of the period length p of the interdigital electrodes.

A microwave resonator magnetic field measuring device (1) for measuring alternating magnetic fields, with a base plate (11) having at least one supporting/bearing/clamping point (111), at least one mechanical oscillator (12+13) formed as a microwave resonator in the form of a cantilever (13) having at least one magnetostrictive layer (12), the latter being connected and mounted at at least one point to the base plate (11) in the at least one supporting/bearing/clamping point (111), at least one input coupling means (161) for microwaves and at least one output coupling means (162) for microwaves, wherein the base plate (11) and the mechanical oscillator (12+13) formed as a microwave resonator are at least partly electrically conductive and electrically conductively connected to one another. Also, a magnetic field measuring method having a magnetic field measuring device according to the invention.

A microwave resonator magnetic field measuring device (1) for measuring alternating magnetic fields, with a base plate (11) having at least one supporting/bearing/clamping point (111), at least one mechanical oscillator (12+13) formed as a microwave resonator in the form of a cantilever (13) having at least one magnetostrictive layer (12), the latter being connected and mounted at at least one point to the base plate (11) in the at least one supporting/bearing/clamping point (111), at least one input coupling means (161) for microwaves and at least one output coupling means (162) for microwaves, wherein the base plate (11) and the mechanical oscillator (12+13) formed as a microwave resonator are at least partly electrically conductive and electrically conductively connected to one another. Also, a magnetic field measuring method having a magnetic field measuring device according to the invention.

A method detects a proportion of a common mode magnetic field transmitted together with a signal magnetic field each emitted by one of at least two magnetic field sensors (S1; S2), wherein the magnetic field sensors (S1; S2) are connected in at least one electric circuit, and at least two differential drive clocks (A; B) reverse the current flowing in the electric circuit.