Role of primary reaction initiated by 254 nm UV light in the degradation of p-nitrophenol attacked by hydroxyl radicals.
The degradation kinetics of p-nitrophenol (p-NP) exposed to 254/185 nm UV light were studied in two modes, i.e., 254 nm UV light intensity enhanced mode and normal mode. It was observed that the extra 254 nm UV light source accelerated the degradation process both in the presence and the absence of oxygen. Considering that hydroxyl radical (*OH) is the dominant factor that causes the degradation of p-NP, the enhanced degradation that occurred in the presence of the extra light source was attributed to the synergistic effect between *OH attack and the primary reactions initiated by 254 nm UV light. The synergistic effect has been confirmed by 266 nm laser flash photolysis (LFP) experiments. It is demonstrated that the phenoxy radical generated from the photoionization of p-NP is capable of reacting with *OH. On the basis of these results, it should be noted that UV light could cause more severe damage to p-NP attacked by *OH in aqueous solution.
C_(60)-地塞米松的激光激发
利用激光光解装置检测了C60-地塞米松(C60-DE)的苯溶液在355nm激光照射下产生的激发三重态,3C60-DE*出现四个吸收峰,分别位于700、440、350和310nm.在330nm处观察到了它的漂白吸收最大值,这与其基态吸收最大值相对应.3C60-DE*能够将能量转移给O2分子而淬灭.与3C60*相比,3C60-DE*的三重态-三重态(T-T)淬灭速率常数减小(3C60*为(5.03±1.31)×109L·mol-1·s-1,3C60-DE*为(3.53±0.87)×109L·mol-1·s-1),而寿命增加了(3C60*为(12.0±2.6)!s,3C60-DE*为(18.0±3.3)μs),这可能是C60分子上连接了地塞米松分子后减小了C60球之间碰撞的几率所致.
Politics of Judicial Independence and Judicial Accountability in Czechia: Bargaining in the Shadow of the Law between Court Presidents and the Ministry of Justice
Judicial independence – Judicial accountability – Court presidents – Judicial politics – Separation of powers – Court administration – Judicial councils – Selection of judges – Czechia – Central Europe