Abstract The development of highly active and stable electrocatalysts for ethanol electroxidation is of decisive importance to the successful commercialization of direct ethanol fuel cells. Despite great efforts invested over the past decade, their progress has been notably slower than expected. In this work, the facile solution synthesis of 2D PdAg alloy nanodendrites as a high‐performance electrocatalyst is reported for ethanol electroxidation. The reaction is carried out via the coreduction of Pd and Ag precursors in aqueous solution with the presence of octadecyltrimethylammonium chloride as the structural directing agent. Final products feature small thickness (5–7 nm) and random in‐plane branching with enlarged surface areas and abundant undercoordinated sites. They exhibit enhanced electrocatalytic activity (large specific current ) and excellent operation stability (as revealed from both the cycling and chronoamperometric tests) for ethanol electroxidation. Control experiments show that the improvement comes from the combined electronic and structural effects.
The visual pullout model box was built, and a series of geogrid pullout tests were conducted to study the micro-macro feature of the soil/geogrid interface. Associating with image visual tracing technique and non-target measuring technique, displacement and shear strain field in the process of pullout was obtained. The results show that the apparent friction coefficient was related with the vertical stress, the sand particles show high gradient changes of displacement and concentration of shear strain in the interface region; the thickness of standard soil/geogrid interface is 6.5 times the average particle size. The study results contribute to providing a new understanding for more in-depth study on the mechanism of the reinforcement interface.
Sodium-ion batteries are potential low-cost alternatives to current lithium-ion technology, yet their performances still fall short of expectation due to the lack of suitable electrode materials with large capacity, long-term cycling stability, and high-rate performance. In this work, we demonstrated that ultrasmall (∼5 nm) iron selenide (FeSe2) nanoparticles exhibited a remarkable activity for sodium-ion storage. They were prepared from a high-temperature solution method with a narrow size distribution and high yield and could be readily redispersed in nonpolar organic solvents. In ether-based electrolyte, FeSe2 nanoparticles exhibited a large specific capacity of ∼500 mAh/g (close to the theoretical limit), high rate capability with ∼250 mAh/g retained at 10 A/g, and excellent cycling stability at both low and high current rates by virtue of their advantageous nanosizing effect. Full sodium-ion batteries were also constructed from coupling FeSe2 with NASICON-type Na3V2(PO4)3 cathode and demonstrated impressive capacity and cycle ability.
For combat simulation, the simulation scenario serves as the foundation and data source. It is not, however, easy to develop military simulation scenario because the developing process of these texts was time-consuming. To solve this problem, in this paper, we propose a distant supervised method for developing military simulation scenarios based on named entity recognition (NER) method. This method consists of three phases: extracting the key elements of simulation scenario, recognizing named entities of the text, and generating an executable simulation scenario. First, we analyze the two types of scenarios involved in the development process of military simulation scenarios: operational scenario and executable scenario. Second, we train a NER model on operational scenario corpus. Then, we compare our distant supervised-based NER method with the other NER methods, and we achieve an overall improvement of F1 score of 9.01%. Finally, to demonstrate the feasibility of our approach, we use a case study to implement a combat simulation scenario development progress.
The Curvelet transform has features such as multi-scale, multi-direction, multi-resolution, etc. It can separate the effective wave and the surface wave in the Curvelet domain by using the characteristics of the frequency, velocity, and direction of the surface wave and the effective wave. Thus it can suppress the surface wave. However, the effect of suppressing the surface wave is affected by the degree of overlapping of the surface wave and the effective wave in the Curvelet domain. In actual seismic data, effective wave and surface wave cannot be completely separated in the Curvelet domain. In this paper, a method of Curvelet threshold iterative based on energy ratio is proposed. First, decomposing the effective wave and the surface wave in the Curvelet domain for many times, then, using different frequency bands and different threshold values to perform multiple information reconstruction, which can effectively separate the effective wave and the surface wave. In this way, a good surface wave suppression effect is achieved.
Abstract Room‐temperature Li/Na‐S batteries are promising energy storage solutions, but unfortunately suffer from serious cycling problems rooted in their polysulfide intermediates. The conventional strategy to tackle this issue is to design host materials for trapping polysulfides via weak physical confinement and interfacial chemical interactions. Even though beneficial, their capability for the polysulfide immobilization is still limited. Herein, the unique sulfiphilic nature of metallic Cu is revisited. Upon the exposure to polysulfide in aqueous or aprotic solution, the surface sulfidization rapidly takes place, resulting in the formation of Cu 2 S nanoflake arrays with tunable texture. When the sulfidized Cu current collector is directly used as the sulfur‐equivalent cathode, it enables high‐performance Li/Na‐S batteries at room temperature with reasonable high sulfur loading. Specific capacities up to ≈1200 mAh g −1 for Li‐S and ≈400 mAh g −1 for Na‐S are measured when normalized to the amount of equivalent sulfur, and can be readily sustained for >1000 cycles.
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