The half-lives are 284·5 ± 1·0 days for Ce 144 71·3 ± 0·2 days for Co 58, 27·8 ± 0·1 days for Cr 51, 2·60 ± 0·2 years for Fe 55, 278 ± 5 days for Mn 54, 2·66 ± 0·02 years for Pm 147, 366·6 ± 0·9 days for Ru 106, and 84·1 ± 0·3...
PURPOSE:To obviate the need to exert a high rotation force and press force on a rotary shaft when a rigid rock-bed is excavated, to prevent early wear of a cutter bit and in its turn eliminate a need for frequent exchange, and to prevent the occurrent of a crack to a bed-rock around...