【单选题】142 / 558已知αs=0.15\alpha_s = 0.15αs=0.15,则ξ=1−1−2αs\xi = 1 - \sqrt{1 - 2\alpha_s}ξ=1−1−2αs约为( )。A0.1630.1630.163正确B0.5180.5180.518C0.850.850.85D0.350.350.35参考答案A参考解析ξ=1−√(1−2αs)≈1−√0.7≈0.163。