positive arc正弧positiveadj.积极的；肯定的；明确的；正面的；正数的；阳性的n.正面；正数；正片；[语]原级positively charged sol(带)阳电(荷)溶胶positive fiscal policy积极财政政策positive time interval正向时间间隔positive birefringence正双射折positive participation积极参与positive speed gearbox减速箱positive chain complex正链复形positive transmutation正片透明度,[冶]正复型(制备负复型的一项中间步骤)positive food reaction[医] 阳性食物反应positive beta particle正β粒子