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: 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.