A method for preventing a control packet loop in a network realizing node redundancy or circuit redundancy based on a rapid spanning tree protocol or a multiple spanning tree protocol is disclosed. In preparing a cathode active material, starting materials for synthesis of a compound represented by the general formula LixFePO4, where 0<x1, are mixed, milled and a carbon material is added to the resulting mass at an optional time point in the course of mixing, milling and sintering. A flow restrictor, such as a viscosity dependent choke or screen, is positioned to restrict fluid flow through the primary outlet. A cured adhesive maintains a space between a surface of the semiconductor chip on which the elastic protrusion is formed and a surface of the elastic substrate on which the leads are formed.