It has been known that the static polarizability of a polymer chain with a biexciton is negative. In order to understand this peculiar fact, this paper studies the dynamical process of the charge transfer in the polym...It has been known that the static polarizability of a polymer chain with a biexciton is negative. In order to understand this peculiar fact, this paper studies the dynamical process of the charge transfer in the polymer chain induced by an external electric held E during forming the biexciton. The time dependence of the charge distribution in the chain reveals that the charge transfer is backward: the positive charge shifts in the opposite direction of the external electric field. Such a backward charge transfer (BCT) produces an opposite dipole, which makes the polarization negative. The effect of electron interaction on the BCT is illustrated.展开更多
Social and economic development directly causes environmental problems, especially water pollution, which directly affects peoples daily water use. Nowadays, the shortage of water resources in the world is relatively ...Social and economic development directly causes environmental problems, especially water pollution, which directly affects peoples daily water use. Nowadays, the shortage of water resources in the world is relatively serious, and water pollution has become an international problem, which is directly related to economic development. Therefore, in view of the water pollution problem in the implementation of urban environmental protection, we must pay enough attention to the ecological environment monitoring, summarize the causes of urban water pollution, and study and formulate feasible countermeasures. Many cities in China have realized the value of sewage treatment in the process of ecological environment monitoring, and have accumulated experience in sewage treatment. However, in the actual treatment process, there are still some problems in urban sewage treatment that need to be solved urgently. It is necessary to optimize and improve the existing system construction in ecological environment monitoring, so as to do a good job in urban environmental protection.展开更多
文摘It has been known that the static polarizability of a polymer chain with a biexciton is negative. In order to understand this peculiar fact, this paper studies the dynamical process of the charge transfer in the polymer chain induced by an external electric held E during forming the biexciton. The time dependence of the charge distribution in the chain reveals that the charge transfer is backward: the positive charge shifts in the opposite direction of the external electric field. Such a backward charge transfer (BCT) produces an opposite dipole, which makes the polarization negative. The effect of electron interaction on the BCT is illustrated.
文摘Social and economic development directly causes environmental problems, especially water pollution, which directly affects peoples daily water use. Nowadays, the shortage of water resources in the world is relatively serious, and water pollution has become an international problem, which is directly related to economic development. Therefore, in view of the water pollution problem in the implementation of urban environmental protection, we must pay enough attention to the ecological environment monitoring, summarize the causes of urban water pollution, and study and formulate feasible countermeasures. Many cities in China have realized the value of sewage treatment in the process of ecological environment monitoring, and have accumulated experience in sewage treatment. However, in the actual treatment process, there are still some problems in urban sewage treatment that need to be solved urgently. It is necessary to optimize and improve the existing system construction in ecological environment monitoring, so as to do a good job in urban environmental protection.
