激发态质子转移分子2-(2'-羟基苯基)苯并噻唑溶液的全光开关效应

研究了激发态质子转移(ESPT)分子2-(2'-羟基苯基)苯并噻唑(HBT)在不同极性溶剂中的光开关行为,探讨了溶剂极性对HBT分子光开光效应的影响.揭示了光开关脉冲信号的形成原因,建立了基于光诱导HBT分子激发态非线性折射效应的皮秒全光开关的理论模型.根据对时间响应函数的理论计算和实验结果分析,确定了光开关脉冲信号下降前沿和上升后沿的形成机理以及影响因素,并提出了增强光开关信号下降前沿的关断深度,提升上升后沿的恢复速度的有效途径和方法.本文工作为制成皮秒量级关断,微秒甚至纳秒量级重新打开的快速全光开关器     

Biochelates as a Cause of Metal Cycling Across the Redoxcline

The sharp concentration peak of the metals Cu, Cd and Zn at the redoxcline of the Framvaren Fjord, Norway, is described as an effect of chelation/complexation with organic ligands. The most dominating ligand is 2-mercaptobenzothiazole (MBT), which binds with a 2 : 1 ligand to metal stoichiometric ratio. MBT has the highest concentrations at the vicinity of the redoxcline where the oxidation of sulfide to elemental sulfur and sulfate is most extensive. We suggest the production being caused by sulfide oxidizing bacteria as we have not been able to detect MBT in pure cultures of sulfate reducing bacteria. Ni does not exhibit the same distribution as the other three metals due to lower preference for coordination with S and N donor atoms and a much lower rate for loss of water than Cu, Cd and Zn.