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All-vanadium redox flow battery (VRFB) is a promising energy storage technique. Flow fields play a crucial role in distributing the electrolyte into the electrode uniformly, but their performance characteristics under different electrode parameters are still unclear. In this work, taking the total pressure drop and total overpotential as performance characterizations, the influence of electrode parameters and operating conditions on the performance of serpentine flow field (SFF) and interdigitated flow field (IFF) are experimentally investigated. It is found that the battery with IFF exhibits lower pressure drop than that with SFF because of the shunt effect of IFF on electrolyte. In terms of promoting the uniform distribution of the electrolyte into the electrode, the SFF outperforms IFF when the electrode porosity is higher than 0.810, but the performance of SFF and IFF could be reversed as the electrode porosity decreases to 0.714, indicating that there may be a performance reversal between SFF and IFF when the electrode porosity decreases from 0.810 to 0.714. Moreover, the increase of current density, the decrease of electrolyte input, and the decrease of electrode thickness strengthen the performance reversal at low electrode porosity. The results well explain the debate on the superiority of IFF and SFF and the discussion on the preference between flow fields and electrode thickness in literatures and provide guidance for the selection of optimal flow field in VRFBs.

We extract a parameter $\xi$, a characteristic product of the strong and electromagnetic amplitudes for the N^*(1535), to be (2.20+-0.15) in unit of 10^(-4)MeV^(-1) from the new data on photoproduction of etas off proton., Comment: will be published in Phys. Rev. Lett

The effects of habitat fragmentations on the forage grass Leymus thinness (Trin.) Tzvel, which has high genetic diversity in northeast China were investigated. Four natural populations of the same ecotype (Grey-green leaf, GGL), namely, BT, ZL, CL and CC (named after location) were collected from different abiotic growing conditions. The CC population has become isolated in a park inside a city by tall buildings though geologically close to CL. Amplified fragment length polymorphism (AFLP) selected primer combinations were highly efficient in revealing the inter-clonal and inter-populational genetic variation in this species. The genetic diversity indices were higher in BT (H = 0.2305) and ZL (0.2467) populations and the lowest in CC (0.1674) population. Cluster analysis showed that the CC population was becoming isolated from the rest with the least gene flow from BT (1.51) as compared from BT to ZL (2.24). Lowest polymorphism was observed in CC (52.31%) as compared to CL (57.69%), BT (70.00%) and ZL (70.38%); this showed a tendency towards homogenization probably due to increased selfing, and due to reduced gene flow apparently caused by city buildings. These results were supported by multiple statistical analyses including Mantel’s test, PCOORDA and AMOVA. Genetic enrichment and epigenetic variation studies can be included in habitat fragmentation analysis and its implications in inducing homogenization and susceptibility in natural plant populations.