A neural network system including a plurality of tiers of interconnected computing elements. The space remaining around the resistor core is filled with a soldermask material and the assembly is coated with metal. When the tape is fired at a sintering temperature of the low temperature ceramic layer, densification occurs in the z direction, but essentially no shrinkage occurs in the x-y planes. In this fishing reel, a large amount of information can be displayed while the size of the reel is kept small. The present invention provides an active material for lithium ion battery represented by a composition formula: LiLi3MgxTi3O4 in which a part of the element of lithium titanate is substituted with Mg, and a lithium ion battery using this active material as a negative electrode active material.