DIMENSIONALITY REDUCTION FOR IMPROVED SOURCE SEPARATION IN FMRI DATA

An improved hollow string comprising a hollow core containing gelatinous oil and a wrapping thread, which is used for rackets for ball games, such as tennis, squash, badminton, etc., and into the hollow cavity of which there is charged gelatinous oil of high viscosity which is in a state of gel at normal temperature and has a melting point of 30 DEG C. or higher and fluidity at a temperature of 50 DEG C. or higher.