浅谈屏蔽室屏蔽效果的控制

该文从影响屏蔽效果的两类因素出发,介绍降低屏蔽效果影响电磁兼容测试准确性的方法。     

The importance of a hot-sequential mechanism in triplet-state formation by charge recombination in reaction centers of bacterial photosynthesis

In photosynthesis, pigment-excitation energies in the antenna system produced by light harvesting are transferred among antenna pigments toward the core antenna, where they are captured by the reaction center and initially fixed in the form of a charge separation. Primary charge separation between an oxidized special pair (P⁺) and a reduced bacteriopheohytin (H⁻) is occasionally intervened by recombination, and a spin-triplet state (³P*) is formed on P in the bacterial reaction center. The ³P* state is harmful to bio-organisms, inducing the formation of the highly damaging singlet oxygen species. Therefore, understanding the ³P*-formation mechanism is important. The ³P* formation is mediated by a state |m〉 of intermediate charge separation between P and the accessory chlorophyll, which is located between P and H. It will be shown theoretically in the present work that at room temperature, not only the mechanism of superexchange by quantum-mechanical virtual mediation at |m〉, but also a hot-sequential mechanism contributes to the mediation. In the latter, although |m〉 is produced as a real state, the final state ³P* is quickly formed during thermalization of phonons in the protein matrix in |m〉. In the former, the final state is formed more quickly before dephasing-thermalization of phonons in |m〉. ³P* is unistep formed from the charge-separated state in the both mechanisms.