Electron-positron pair production in a strong asymmetric laser electric field

By solving the quantum Vlasov equation, electron positron pair production in a strong electric field with asymmetric laser pulses has been investigated. We consider three different situations of subcycle, cycle and supercycle laser pulses. It is found that in asymmetric laser pulse field, i.e.. when the pulse length of one rising or falling side is fixed while the pulse length of the other side is changed, the pair production rate and mnnber density can be significantly modified comparable to symmetric situation. For each ca,se of these three different cycle pulses, when one side pulse length is constant and the other side pulse length becomes shorter, i.e., the whole pulse is compressed, the more pairs can be produced than that in tile vice versa case, i.e., the whole pulse is elongated. In compressed pulse case there exists an optimum pulse length ratio of asylnmetric pulse lengths which makes the pair number density maximunn. Moreover, the created maximum pair number density by subcycle pulse is larger than that by cycle or/and supercycle pulse. In elongated pulse case, however, only for supercycle laser pulse the created pairs is enhanced and there exists also an optimum asymmetric pulse length ratio that maximizes the pair number density. On the other hand. surprisingly, in both cases of subcycle and cycle elongated laser pulses, the pair number density is monotonically decreasing as the asymmetry of pulse increases.     

利用四丁基溴化铵——硫酸铵双水相萃取法萃取结晶紫的行为研究

本文利用四丁基溴化铵（TBAB）-硫酸铵-水双水相体系，研究了结晶紫萃取行为，结晶紫与四丁基溴化铵形成离子结合物，被萃取到TBAB相，其配合物最大吸收波长位于590nm，摩尔吸光系数ε=1．1×10^5L／（mol·cm），线性回归方程为A=0．0005＋0．1785C，相关系数r=0．9999，线性范围0-80μg．     

利用四丁基溴化铵—硫酸铵双水相萃取法萃取结晶紫的行为研究

本文利用四丁基溴化铵(TBAB)—硫酸铵—水双水相体系,研究了结晶紫萃取行为,结晶紫与四丁基溴化铵形成离子缔合物,被萃取到TBAB相,其配合物最大吸收波长位于590 nm,摩尔吸光系数=ε1.1×105L/(m o l.cm),线性回归方程为A=0.000 5 0.178 5C,相关系数r=0.999 9,线性范围0-80μg.