Using the Landauer formula and the quantum S-matrix scattering theory, we derive a resistance formula for multi-barrier structure under phase coherent transmission condition. This formula shows that when the transport...Using the Landauer formula and the quantum S-matrix scattering theory, we derive a resistance formula for multi-barrier structure under phase coherent transmission condition. This formula shows that when the transport is coherent, the potential wells of the structure are just like conductors contributing to the overall resistance. And because the resistance formula is derived based on the scattering theory, the barrier resistance will change with the number of scattering centres （i.e. the number of barriers） in the structure.展开更多
基于冲突的搜索算法(Conflict Base Search,CBS)是当前多智能体路径规划的主要方法之一,并且它与互斥锁传播(Mutex Propagation,MP)方法结合还能够进一步提升搜索无冲突路径的性能。然而,基于冲突与互斥锁传播的搜索算法(CBS-MP)存在难...基于冲突的搜索算法(Conflict Base Search,CBS)是当前多智能体路径规划的主要方法之一,并且它与互斥锁传播(Mutex Propagation,MP)方法结合还能够进一步提升搜索无冲突路径的性能。然而,基于冲突与互斥锁传播的搜索算法(CBS-MP)存在难以准确区分次要冲突和一般冲突的问题。为此,提出基于解空间裁剪程度的CBS-MP算法。该方法通过设定不同互斥锁对于解空间的裁剪程度为启发值,搜索出对于其他智能体解空间影响程度最小的路径解,然后将得到的路径解作为其他智能体的约束,搜索彼此无冲突的解。相比于现有CBS-MP算法,该方法不仅完善了对于不同碰撞类型的处理,还进一步提升路径搜索性能。实验结果表明在一般冲突和次要冲突频发的无障碍环境中该方法的性能优势较为明显。展开更多
To manage potential microbial risks and meet increasingly strict drinking water health standards,UV treatment has attracted increasing attention for use in drinking water systems in China.However,the effects of UV tre...To manage potential microbial risks and meet increasingly strict drinking water health standards,UV treatment has attracted increasing attention for use in drinking water systems in China.However,the effects of UV treatment on microbial control and disinfection byproducts(DBPs)formation in real municipal drinking water systems are poorly understood.Here,we collected water samples from three real drinking water systems in Beijing and Tianjin to investigate the impacts of UV treatment on microbial control and DBP formation.We employed heterotrophic plate count(HPC),flow cytometry(FCM),quantitative PCR analysis,and high-throughput sequencing to measure microorganisms in the samples.Different trends were observed between HPC and total cell count(measured by FCM),indicating that a single indicator could not reflect the real degree of biological re-growth in drinking water distribution systems(DWDSs).A significant increase in the 16S rRNA gene concentration was observed when the UV system was stopped.Besides,the bacterial community composition was similar at the phylum level but differed markedly at the genera level among the three DWDSs.Some chlorine-resistant bacteria,including potential pathogens(e.g.,Acinetobacter)showed a high relative abundance when the UV system was turned off.It can be concluded that UV treatment can mitigate microbial re-growth to some extent.Finally,UV treatment had a limited influence on the formation of DBPs,including trihalomethanes,haloacetic acids,and nitrogenated DBPs.The findings of this study may help to understand the performance of UV treatment in real drinking water systems.展开更多
文摘Using the Landauer formula and the quantum S-matrix scattering theory, we derive a resistance formula for multi-barrier structure under phase coherent transmission condition. This formula shows that when the transport is coherent, the potential wells of the structure are just like conductors contributing to the overall resistance. And because the resistance formula is derived based on the scattering theory, the barrier resistance will change with the number of scattering centres （i.e. the number of barriers） in the structure.
文摘基于冲突的搜索算法(Conflict Base Search,CBS)是当前多智能体路径规划的主要方法之一,并且它与互斥锁传播(Mutex Propagation,MP)方法结合还能够进一步提升搜索无冲突路径的性能。然而,基于冲突与互斥锁传播的搜索算法(CBS-MP)存在难以准确区分次要冲突和一般冲突的问题。为此,提出基于解空间裁剪程度的CBS-MP算法。该方法通过设定不同互斥锁对于解空间的裁剪程度为启发值,搜索出对于其他智能体解空间影响程度最小的路径解,然后将得到的路径解作为其他智能体的约束,搜索彼此无冲突的解。相比于现有CBS-MP算法,该方法不仅完善了对于不同碰撞类型的处理,还进一步提升路径搜索性能。实验结果表明在一般冲突和次要冲突频发的无障碍环境中该方法的性能优势较为明显。
基金supported by the National Natural Science Foundation of China(Nos.51778323,51761125013 and51290284)the National Science and Technology Major Project of China(Nos.2012ZX07404-002,2017ZX07108-003 and 2017ZX07502-003)
文摘To manage potential microbial risks and meet increasingly strict drinking water health standards,UV treatment has attracted increasing attention for use in drinking water systems in China.However,the effects of UV treatment on microbial control and disinfection byproducts(DBPs)formation in real municipal drinking water systems are poorly understood.Here,we collected water samples from three real drinking water systems in Beijing and Tianjin to investigate the impacts of UV treatment on microbial control and DBP formation.We employed heterotrophic plate count(HPC),flow cytometry(FCM),quantitative PCR analysis,and high-throughput sequencing to measure microorganisms in the samples.Different trends were observed between HPC and total cell count(measured by FCM),indicating that a single indicator could not reflect the real degree of biological re-growth in drinking water distribution systems(DWDSs).A significant increase in the 16S rRNA gene concentration was observed when the UV system was stopped.Besides,the bacterial community composition was similar at the phylum level but differed markedly at the genera level among the three DWDSs.Some chlorine-resistant bacteria,including potential pathogens(e.g.,Acinetobacter)showed a high relative abundance when the UV system was turned off.It can be concluded that UV treatment can mitigate microbial re-growth to some extent.Finally,UV treatment had a limited influence on the formation of DBPs,including trihalomethanes,haloacetic acids,and nitrogenated DBPs.The findings of this study may help to understand the performance of UV treatment in real drinking water systems.
