高フープ応力耐性と低遮蔽電流性を両立するHTSコイル技術に向けて(2) 〜高強度Bi-2223コイルの遮蔽電流の単芯/多芯モード転移〜けて (Towards HTS coil technology with combination of high hoop stress tolerance and small screening current induced field (2) ~ Mono / multi-filament mode transition for a high-strength Bi-2223 conductor coil ~)