Abstract: A method for fabricating an impregnated type cathode comprises the steps of mixing metal powder having a high melting point and a heat proof property, and electron emission substance powder in a dry state, pressing the mixed powder to provide a pressed mixture, and applying an isostatic pressure to the pressed mixture contained in a sealed capsule. At the mixing stage, the metal powder is heated by a high temperature lower than the melting point, and at the mixing stage, a sintered mixture is obtained. In this method, the steps are simplified and decreased in number to decrease a fabricating cost. Furthermore, no influence occurs in electron emission due to hydrooxides.

Abstract: Effective disinfection and washing of immobilized lactase from Aspergillus oryzae is carried out after a period of hydrolyzing lactose by treatment of the immobilized lactase with aqueous solutions of pH's 2 to 4 and 6 to 8.7, one or both of which contain a disinfectant. The solution having a pH of 6 to 8.7 may be a phosphate buffered solution. The lactase may be immobilized on a high polymer compound by covalent linkage. The immobilized lactase has outstanding resistance to chemicals and wide pH stability so that decrease of lactase activity is minimized.