Abstract: An apparatus for detecting periodic defects includes a sensor that obtains signals to evaluate properties of an area having a length longer than an expected defect period; a small area selector that separates small areas whose area length is shorter than that of the area so that all adjacent distance intervals are equal in a periodic defect arrangement direction, and selecting signals corresponding to the positions of the plurality of small areas from outputs from the sensor; an evaluation index calculator that calculates a similarity evaluation index between signal patterns among signals selected by the small area selector; a set value changer that changes the positions of the small areas and the distance interval, and repeating computational processings of the small area selector and the evaluation index calculator; and a period judgment device that judges the distance interval as a period when the evaluation index is higher than a value.

Abstract: A magnetism measuring method includes magnetizing a magnetic material with a direct current to a rotational magnetization region, performing an alternate current excitation in a direction having a component orthogonal to a direction of the direct current magnetization, and measuring a component of an alternate current magnetic field generated by an interaction with the magnetic material in a direction orthogonal to the direction of the direct current magnetization.

Abstract: A detection method for detecting a concavo-convex shape surface defect existing on a ferromagnetic metal object including sensing a signal attributed to strain of the concavo-convex shape surface defect having a size in a range of 0.5 to 6 ?m. The signal is magnetic flux leaking from the ferromagnetic metal to which magnetic flux is applied. A detecting apparatus incorporates a magnetizer for magnetizing a ferromagnetic metal and a plurality of magnetic sensors arranged in the direction perpendicular to a traveling direction of the ferromagnetic metal to sense a signal attributed to strain of a concavo-convex shape surface defect having a size in a range of 0.5 to 6 ?m.

Abstract: A magnetism measuring method includes magnetizing a magnetic material with a direct current to a rotational magnetization region, performing an alternate current excitation in a direction having a component orthogonal to a direction of the direct current magnetization, and measuring a component of an alternate current magnetic field generated by an interaction with the magnetic material in a direction orthogonal to the direction of the direct current magnetization.

Abstract: An apparatus for detecting periodic defects includes a sensor that obtains signals to evaluate properties of an area having a length longer than an expected defect period on a target sample; a small area selector that separates a plurality of small areas whose area length is shorter than that of the area so that all distance intervals adjacent to one another are equal in a periodic defect arrangement direction to determine positions of the plurality of small areas, and selecting signals corresponding to the positions of the plurality of small areas from outputs from the sensor; an evaluation index calculator that calculates a similarity evaluation index between signal patterns among a plurality of signals selected by the small area selector; a set value changer that changes the positions of the small areas and the distance interval, and repeating computational processings of the small area selector and the evaluation index calculator; and a period judgment device that judges the distance interval as a period

Abstract: A detection method for detecting a concavo-convex shape surface defect existing on a ferromagnetic metal object including sensing a signal attributed to strain of the concavo-convex shape surface defect having a size in a range of 0.5 to 6 ?m. The signal is magnetic flux leaking from the ferromagnetic metal to which magnetic flux is applied. A detecting apparatus incorporates a magnetizer for magnetizing a ferromagnetic metal and a plurality of magnetic sensors arranged in the direction perpendicular to a traveling direction of the ferromagnetic metal to sense a signal attributed to strain of a concavo-convex shape surface defect having a size in a range of 0.5 to 6 ?m.

Abstract: The object of the invention is to measure, surely and in a stable condition, the orientation of a pig body in the pipe of a pipeline thereby to correct errors caused by measuring the linear shape of the pipeline by means of a gyroscope sensor. A three-axis gyroscope sensor unit 4 is placed in a pig body 2 such that one of measuring axes of the gyroscope sensor unit 4 is parallel to the center axis of the pig body 2 and is fixed so as to prevent the gyroscope sensor unit 4 from being shifted in position with respect to the pig body 2. Two sets of six distance measuring means 5-10 and 11-16 are arranged on the outer periphery of the pig body 2 at two positions in the back and forth direction (in a direction of travel), respectively, and the six distance measuring means of each set are arranged at equal intervals in the circumferential direction of the pig body 2.

Abstract: The present invention provides a leakage flux flaw detecting method in which a ferromagnetic substance such as a steel sheet or coil is magnetized by a plurality of magnetic fields with different intensity and magnetic flux leaking from the ferromagnetic substance having been magnetized is detected by a magnetic sensor, and output signals of the magnetic sensor after the detection of leakage flux are processed so that a signal caused by a flaw in the ferromagnetic substance is highlighted. Since this leakage flux flaw detecting method makes it possible to detect flaws with high accuracy, a scaled or descaled hot rolled steel sheet or coil in which the accurate flaw information such as location, density, size, and the like is known can be provided by applying this method to the manufacturing of hot rolled steel sheet or coil.

Abstract: The present invention provides a leakage flux flaw detecting method in which a ferromagnetic substance such as a steel sheet or coil is magnetized by a plurality of magnetic fields with different intensity and magnetic flux leaking from the ferromagnetic substance having been magnetized is detected by a magnetic sensor, and output signals of the magnetic sensor after the detection of leakage flux are processed so that a signal caused by a flaw in the ferromagnetic substance is highlighted. Since this leakage flux flaw detecting method makes it possible to detect flaws with high accuracy, a scaled or descaled hot rolled steel sheet or coil in which the accurate flaw information such as location, density, size, and the like is known can be provided by applying this method to the manufacturing of hot rolled steel sheet or coil.

Abstract: A magnetic sensor in which magnetic leakage flaw detection can be performed with high accuracy without so reducing liftoff, and a magnetic flaw detection method and apparatus to which the magnetic sensor is applied. The magnetic sensor 50 for detecting magnetic flux generated due to a defect portion of a magnetized subject to be inspected has an E-shaped core 51 having magnetic poles (51a, 51b and 51c) arranged in the neighborhood of a steel plate (13) to be inspected, and a search coil (52) wound on the center magnetic pole (51b) of the E-shaped core for detecting the magnetic flux. An external magnetic field floating in the circumference of the E-shaped magnetic sensor passes through the opposite side magnetic poles (51a and 51c) of the E-shaped core 51 but does not cross the center magnetic pole (51b) of the E-shaped core. Accordingly, no voltage due to the external magnetic field is induced in the search coil (52), so that only the magnetic flux caused by the defect portion is detected.

Abstract: A continuous-casting operation controlling method and apparatus in which: the molten-bath level of molten steel in a mold is detected in a period of from the time point just after the start of injection of the molten steel to the time point when the molten-bath level reaches a molten-bath level for the steady-state operation; and the quantity of discharge of the molten steel is controlled appropriately on the basis of the detected molten-bath level to thereby make it possible to start drawing-out of casting automatically. The molten-bath level is measured continuously by an electrode type molten-bath level meter, so that the molten-bath level ascending rate is obtained on the basis of the change of the molten-bath level. The flow rate of the molten steel discharged from a tundish is adjusted on the basis of the deviation of the molten-bath level ascending rate from a reference rate.

Abstract: First and second electrodes are inserted into molten metal. A first pseudo random signal is transmitted to the first electrode, and at the same time the first pseudo random signal and a second pseudo random signal which has the same pattern as the first pseudo random signal but which is slightly different in frequency from the first pseudo random signal are multiplied by each other in a first multiplier to thereby calculate a first product value. A signal obtained from the second electrode and the second pseudo random signal are multiplied by each other in a second multiplier to thereby obtain a second product value. The displacement of the molten metal is calculated from the time difference between maximum correlation values respectively appearing in time series patterns of the first and second product values.

Abstract: A distance measuring method and an apparatus therefor, in which used are first and second pseudo random signals which are equal to each other in pattern but slight different from each other in frequency. A first time-series pattern obtained by multiplying the first pseudo random signal by the second pseudo random signal is generated, laser light intensity-modulated with the first pseudo random signal is radiated to a target, the light reflected from the target is received, and a intensity change of the received reflected-light is converted into an electric signal. A second time-series pattern is obtained by multiplying the electric signal as a reception signal with the second pseudo random signal. The distance to the target is measured by calculating the time difference between the first and second time-series patterns.

Abstract: An underground radar tomography in which an electromagnetic wave is radiated into the ground, the amplitude and propagation time of a transmitted wave, a reflected wave or a diffracted wave of the electromagnetic wave are measured at a number of points, and signal processing is performed on the result of measurement to thereby obtain the distribution of strata and soil in the ground as section information with a high accuracy. By use of two pseudo random signals which are slightly different in period but the same in code pattern, measurement time which is expanded relative to propagation time is obtained to thereby make the measurement accuracy high.

Abstract: Disclosed is a in-furnace slag level measuring method for measuring a slag level in a convertor and an apparatus therefor. A sublance and an antenna of a microwaver radar are arranged exchangeable therebetween so that the sublance and the antenna are alternatively inserted in to the convertor from about the convertor. The antenna is inserted into the convertor in first and middle stage of the refining operation of the converter to thereby measure the slag level, and the sublance is inserted into the convertor to thereby perform various measurement.

Abstract: An in-furnace level meter for measuring a slag level, or the like, in a convertor, and an antenna used therefore. An antenna position is controlled so that the distance between the antenna inserted in the convertor and the slag level can be established to be constant or within a predetermined range. A water-cooled structure antenna is used as the antenna.

Abstract: Disclosed is an in-furnace slag level measuring apparatus having a microwave radar for measuring a slag level in a convertor or the like. The level of a transmission signal or a reception signal is adjusted in accordance with the level of a detection signal so that the signal level in the microwave radar is adjusted to be constant. Further, the level measurement value and the detection signal are inputted and the level measurement values obtained in a predetermined time are subjected to averaging operation. In the averaging operation, when the detection signal is smaller than a set point, the averaging operation is performed while disregarding the level measurement value at that time.

Abstract: A distance measuring method and apparatus in which first and second pseudo random signals which are the same in pattern but slightly different in period are generated to obtain a correlation output of the first and second pseudo random signals before transmission thereof as a reference correlation output, and the first pseudo random signal is directly transmitted toward a target or alternatively a carrier wave is modulated by the first pseudo random signal and transmitted toward the target. A correlation output of the signal reflected and received from the target and the second pseudo random signal is detected and the distance to the target is measured from the time interval between the reference correlation output and the received correlation output.

Abstract: A method for continuous casting of steel comprises charging molten steel from a tundish into a mold through exit ports of an immersion nozzle, introducing a magnetic field vertically to a flow of the molten steel from the exit ports by the use of at least a pair of direct current magnets which are arranged on the outer side of copper plates on the wide side of the mold, the immersion nozzle being placed between the direct current magnets and polarities of magnetisms on the top side of the magnets being the same, and casting the molten steel at a predetermined casting rate. One magnetic pole of the direct current magnet is positioned at an upper end of copper plate on the wide side of the mold and the other magnetic pole being positioned at lower than the exit port of the immersion nozzle and on the outer side of copper plate on the wide side of the mold. The immersion nozzle has two exit ports, each of which has an angle of 15.degree. to 45.degree. downward.

Abstract: A distance measuring method and apparatus in which first and second pseudo random signals which are the same in pattern but slightly different in period are generated to obtain a correlation output of the first and second pseudo random signals before transmission thereof as a reference correlation output, and the first pseudo random signal is directly transmitted toward a target or alternatively a carrier wave is modulated by the first pseudo random signal and transmitted toward the target. A correlation output of the signal reflected and received from the target and the second pseudo random signal is detected and the distance to the target is measured from the time interval between the reference correlation output and the received correlation output.