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A time-of-arrival (TOA) system based on GPS technology for locating VHF radiation sources from lightning has been developed and used in observation sites in the northern Shandong Province, China. The 3D images of the lightning progression have been obtained successfully for the first time in China. The 3D-channel evolutions of typical negative CG, positive CG and IC lightning flashes have been discussed together with the data of fast electric field change. It was found that significant differences existed between the negative and positive CG lightning flashes in terms of the initiation and propagation of the radiation sources. The preliminary breakdown of a negative CG lightning flash propagated at a speed about 5.2×10 4 m/s. The stepped leader of negative CG lightning flashes was trigged by negative initial breakdown. Thereafter, it propagated downward at a speed of 1.3×10 5 m/s. The initial process of the positive CG lightning flashes was also a propagation process of negative streamer. These streamers propagated dominantly horizontally in the positive charge region and accumulated positive charges at the origin of the lightning, and as a consequence, initiated downward positive streamers. A new type of lightning discharge that was triggered by a narrow bipolar pulse (NBP) is discussed in this study. The NBP was originated at altitude of about 10.5 km in the upper positive charge region. As a distinct difference from normal IC flash, its channels extended horizontally all around and produced a lot of radiation sources. The source power of the NBP could approach 16.7 kW, which is much greater than that of normal lightning discharge ranging between 100 mW and 500 W. The 3D propagation of this new type of lightning discharge was observed and obtained for the first time in China. The possible initiation mechanism of this new type of lightning is discussed here. time-of-arrival (TOA) technique, three dimensional lightning locating system, discharge process, narrow bipolar pulse, new-type of IC lightning Citation:Zhang G S, Wang Y H, Qie X S, et al. Using lightning locating system based on time-of-arrival technique to study three-dimensional lightning discharge processes.Realization of three dimensional (3D) location of lightning radiation process provides a new approach to study meticulously the lightning discharge process, as well as the electrical structure of thunderstorms and their electrification mechanism. Lightning discharges are categorized as cloudto-ground (CG) and intracloud (IC) flashes. People are more concentrated on the CG flash since CG flash is the cause of most lightning damage, injury, and death. Many meaningful results [1-3] based on the lightning locating technology and

Crystal phase engineering is a powerful strategy for regulating the performance of electrocatalysts toward many electrocatalytic reactions. Herein we demonstrate that Au@Pd1Cu concave nanocubes (CNCs) with an ordered body-centered cubic (bcc) PdCu alloy shell enclosed by many high active high-index facets can be adopted as highly active yet stable electrocatalysts for the ethanol oxidation reaction (EOR). These CNCs are more efficient than other nanocrystals with a disordered face-centered cubic (fcc) PdCu alloy surface and display high mass and specific activities of 10.59 A mgpd –1 and 33.24 mA cm–2, which are 11.7 times and 4.1 times higher than those of commercial Pd black, respectively. Our core–shell CNCs also exhibit robust durability with the weakest decay in activity after 250 potential-scanning cycles, as well as outstanding antipoisoning ability. Alloying with Cu and the ordered bcc phase surface can provide abundant OHads species to oxidize carbonaceous poison to avoid catalyst poisoning, and the exposed high-index facets on the surface can act as highly catalytic sites.

Development of efficient and robust electrocatalysts for complete oxidation of ethanol is critical for the commercialization of direct ethanol fuel cells. However, the complete oxidation of ethanol suffers from poor efficiency due to the low C1 pathway selectivity. Herein, single‐atomic Ir (Ir1) on hcp‐PtPb/fcc‐Pt core–shell hexagonal nanoplates (PtPb@PtIr1 HNPs) enclosed by Pt(110) surface with a 7.2% tensile strain is constructed to drive complete electro‐oxidation of ethanol. Benefiting from the construction of Ir1 sites, the PtPb@PtIr1 HNPs exhibit a Faraday efficiency of 57.93% for the C1 pathway, which is ≈8.3 times higher than that of the commercial Pt/C‐JM. Furthermore, the PtPb@PtIr1 HNPs show a top‐ranked electro‐activity achieving 45.1‐fold and 56.3‐fold higher than the specific and mass activities of Pt/C‐JM, respectively. Meanwhile, the durability can be significantly enhanced by the construction of Ir1 sites. Density functional theory calculations indicate that the strong synergy on the PtPb@PtIr1 HNPs surface significantly promotes the breaking of CC bond of CH2CO* and facilitates CO oxidation and suppresses the deactivation of the catalyst. This work offers a unique single‐atom approach using low‐coordination active sites on shape‐controlled nanocrystals to tune the selectivity and activity toward complicated catalytic reactions.