Abstract: Decalcification can be performed by using acid or other agents. It may be difficult to decalcify large bone block within ours. This invention provides a bone-decalcifying agent including a calcium desolving agent for desolving calcium ions of bones, and a bubble-forming agent for generating microbubbles when the bone-decalcifying agent is exposed to ultrasonic vibration. It is found that bones may be decalcified in a relatively short time using the bone-decalcifying agent of this invention.

Abstract: A lock device controlled by both mechanical force and magnetic force, comprising a cylinder having at least a group of mechanical pins and a group of magnetic pins; said group of magnetic pins including a slidable magnetic pin in the pin bore of the plug and a slidable metal pin in the pin bore of the shell; a key that matches with said lock device, when said key is inserted into the plug, a plurality of recesses of key match with the mechanical pins which are disposed in the pin bores of the plug; and a plurality of magnetic balls in the key match with the magnetic pins which are disposed in the pin bores of the plug; when the key is not inserted in plug, the metal pins partially extend into the pin bores of plug and bridge the shear plane between the plug and the shell by the action of a coil spring that locates in the pin bore of the shell; and polarities of the poles of the magnetic balls in the key and the opposite magnetic pins on their neighborhood faces are identical.