注重逻辑推理,提升几何综合能力——以圆的有关知识学习为例

日常教学中,我们经常发现初中生的几何综合分析能力还有较明显的欠缺,而这一能力的提升并非一朝一夕的努力或训练就能达成的,要提高这方面的能力,需要学生充分地经历独立思考的过程.因此在教学中,需要教给学生如何从繁杂的题干信息和问题结论中分析、提取有效信息,如何从复杂的图形条件中剥离出简单的基本图形,如何根据具体条件构造有效、准确的辅助线,这些都需要在平时的教学中和学生一起经历思考、分析、总结的过程,这样学生才能积累活动经验,理解数学本质,提升综合应用能力,同时能促进逻辑推理能力的提升.     

Energy transfer between two aggregates in light-harvesting complexes

Energy transfer processes between two aggregates in a coupled chromophoric-pigment(protein)system are studied via the standard master equation approach.Each pigment of the two aggregates is modeled as a two-level system.The excitation energy is assumed to be transferred from the donor aggregate to the acceptor aggregate.The model can be used to theoretically simulate many aspects of light-harvesting complexes(LHCs).By applying the real bio-parameters of photosynthesis,we numerically investigate the efficiency of energy transfer(EET)between the two aggregates in terms of some factors,e.g.,the initial coherence of the donor aggregate,the coupling strengthes between the two aggregates and between different pigments,and the effects of noise from the environment.Our results provide evidence for that the actual numbers of pigments in the chromophoric rings of LHCs should be the optimum parameters for a high EET.We also give a detailed analysis of the effects of noise on the EET.