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单滴液相微萃取-高效液相色谱法测定水中二甲戊乐灵农药残留 总被引:6,自引:1,他引:6
应用单滴液相微萃取(SD-LPME)技术建立了水体中二甲戊乐灵农药的高效液相色谱(HPLC)分析方法.研究了不同的萃取条件(萃取剂、体积、萃取时间、搅拌速度、温度等)及测定条件对检测二甲戊乐灵的影响,确定了最佳萃取条件:环己烷作萃取剂,萃取剂体积5 μL,液滴体积2 μL,搅拌速度350 r/min,35 ℃条件下萃取35 min.应用此方法测定了自来水和太湖水样中的二甲戊乐灵农药残留,相对标准偏差(RSD)在2 5%~3.4%(n=6)之间;回收率为88.0%~99.8%. 相似文献
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We confirm our previous prediction of a d* state with I(JP)=0(3+) [Phys. Rev. C 60, 045203 (1999)] and report for the first time based on a microscopic calculation that d* has about 2/3 hidden color (CC) configurations and thus is a hexaquark-dominated exotic state. By performing a more elaborate dynamical coupled-channels investigation of the ΔΔ-CC system within the framework of the resonating group method (RGM) in a chiral quark model, we find that the d* state has a mass of about 2.38--2.42 GeV, a root-mean-square radius (RMS) of 0.76--0.88 fm, and a CC fraction of 66%--68%. The last may cause a rather narrow width for the d* which, together with the quantum numbers and our calculated mass, is consistent with the newly observed resonance-like structure (M≈ 2380 MeV, Γ≈ 70 MeV) in double-pionic fusion reactions reported by the WASA-at-COSY Collaboration. 相似文献
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在手征SU(3)夸克模型和扩展的手征SU(3)夸克模型的框架下, 用变分的方法系统地研究了同位旋为0、1, 自旋宇称为0+、1+和2+的udss四夸克系统6个低组态的能量. 模型的参数取自以前的工作, 它能很好地描述核子-核子散射相移以及核子-超子散射截面. S道相互作用的参数由拟合K介子和K*介子的质量定出, 并且考虑了具有相同量子数的态之间的态混合效应. 结果表明, 同位旋为0且自旋宇称为1+的udss能量低于相应的K*K*,的阈能, 且该组态中KK*的成分相当小, 因此该组态的宽度可能较小, 可视为一个可能的四夸克态的候选者. 相似文献
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