Abstract: Provided is a method of, in ladle refining treatment of a molten steel, accurately estimating the molten steel temperature after the ladle refining treatment. An operation method of ladle refining treatment by which ladle refining treatment of a molten steel is performed while continuously measuring a molten steel temperature during operation of the ladle refining treatment of the molten steel comprises setting a time earlier than a scheduled ending time of the ladle refining treatment in a continuous measurement period of the molten steel temperature as a determination timing, and estimating the molten steel temperature at the scheduled ending time on the basis of a change with time of the molten steel temperature in continuous measured data of the molten steel temperature from a start of continuous measurement of the molten steel temperature to the determination timing.

Abstract: A handle for an idiophone such as a claves has a tubular grip internally provided with a resonant chamber opening towards the main body of the musical instrument for generation of high tonal pitch sounds with long decay time.

Abstract: A musical instrument such as a jingle, a tambourine or a tomtom is provided with two or more hollow resonators arranged in the vicinity of at least one tone generator such as a pair of jingle discs or a head and preferably selectively closable by means of a slider coupled movably to the body of the instrument. Presence of a plurality of resonators, preferably different in resonance characteristics, assures colorful and rich resonance of tones generated by the tone generator and use of the slider enables easy and free finger control on the mode of resonance.

Abstract: In construction of an idiophone such as a tambourine having paired metallic jingles idly supported by carrier rods in respective windows formed transversely through an elongated shell, each carrier rod is fixed at both ends by inner ridges of the shell and the end of each shell project inwards beyond walls of the shell. Multiple phased collisions between the jingles, between the jingles and the ridges and between the jingles and the walls enable generation of colorful musical tones with rich acoustic variety and tone quality.

Abstract: In construction of a percussive musical instrument such as a wood block having at least one striker head and an internal resonator chamber for resonation of vibrations generated at the striker head, at least one round striker head is arranged along at least one slit formed in communication with the resonator chamber for exact and easy generation of intended musical tones regardless of the swing mode of a stick.