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Rationally modulating the binding strength of reaction intermediates on surface sites of copper-based catalysts could facilitate C–C coupling to generate multicarbon products in an electrochemical CO2reduction reaction. Herein, theoretical calculations reveal that cascade Ag–Cu dual sites could synergistically increase local CO coverage and lower the kinetic barrier for CO protonation, leading to enhanced asymmetric C–C coupling to generate C2H4. As a proof of concept, the Cu3N-Ag nanocubes (NCs) with Ag located in partial Cu sites and a Cu3N unit center are successfully synthesized. The Faraday efficiency and partial current density of C2H4over Cu3N-Ag NCs are 7.8 and 9.0 times those of Cu3N NCs, respectively. In situ spectroscopies combined with theoretical calculations confirm that Ag sites produce CO and Cu sites promote asymmetric C–C coupling to *COCHO, significantly enhancing the generation of C2H4. Our work provides new insights into the cascade catalysis strategy at the atomic scale for boosting CO2to multicarbon products.

To realize online noncontact detection of the degree of chemical corrosion of stone cultural relics, we developed a reflective fiber-optic sensor, and a theoretical model was established. The sensor comprised incident and receiving coaxial fibers located in the middle and inner and outer layers of the coaxial fiber, respectively. We investigated the effects of the number of receiving fibers in the outer layer and the distance between the end face of the sensing probe and the detection object on the relative light intensity of the sensor output. The response characteristics of the sensor to sandstone samples with different degrees of corrosion were examined, and the change in the material composition of the sandstone after acid corrosion was studied. For a fiber diameter of $400 \mu \text{m}$ , the numbers of outgoing, inner receiving, and outer receiving fibers are 6, 1, and 6, respectively. Furthermore, the spacing of the outer receiving fiber was $100 \mu \text{m}$ , and the relative light intensity of the sensor output reached the highest $\sim $ 90%. Following the start of corrosion of sandstone, with a decrease in the pH of the corrosion solution, the sandstone becomes more seriously corroded, and the decrease in the iron ions and changes in the surface microstructure lower the quality of the spectral output of the sensor. The reflectance spectrum (400 nm) of the sensor reached the highest value of $\sim $ 90%, the sensor reflectance spectrum and sandstone iron ion content exhibited a linear relationship, and the sensitivity reached 36.591 per percentage content change.

In a complex electromagnetic environment, radar signal deinterleaving (RSD) is a challenging task. In this article, a deep contrastive clustering algorithm (DCCA) is advanced in a new self-supervised paradigm for the accurate RSD without any prior information about radar emitters. First, a contrastive self-supervised deep attention network (CSDAN) is constructed to learn signal representations by using self-defined pseudolabels of augmented signals as supervision. We use CSDAN to learn the differences between different radiation source data and generate deep features suitable for clustering. Three metrics are then used to automatically determine the number of clusters for the subsequent clustering. Extensive experiments are performed on several datasets containing different numbers of emitters. The results show that the proposed DCCA can accurately determine the number of emitters and deinterleave radar pulses. Furthermore, CSDAN can extract discriminative features of emitters with low intraclass similarity and high interclass similarity.

Designing and constructing bifunctional electrocatalysts with high efficiency, high stability and low cost for overall water splitting to produce clean hydrogen fuel is attractive but highly challenging. Here we constructed puffed quaternary FexCoyNi1-x-yP nanoarrays as bifunctional electrodes for robust overall water splitting. The iron was used as the modulator to manipulate the electron density of NiCoP nanoarray, which could increase the positive charges of metal (Ni and Co) and P sites. The resultant electronic structure of FexCoyNi1-x-yP was supposed to balance the adsorption and desorption of H and accelerate the oxygen evolution reaction (OER) kinetics. Moreover, the morphological structure of FexCoyNi1-x-yP was modulated through the kinetically controlled alkaline etching by using the amphoteric features of initial FeCoNi hydroxide nanowires. The resultant puffed structure has rich porosity, cavity and defects, which benefit the exposure of more active sites and the transport of mass/ charge. As a result, the cell integrated with the puffed quaternary FexCoyNi1-x-yP nanoarrays as both the cathode and anode only requires the overpotentials of 25 and 230 mV for hydrogen evolution reaction (HER) and OER at the current density of 10 mA cm-2in alkaline media and a cell voltage of 1.48 V to drive the overall water splitting. Moreover, the puffed FexCoyNi1-x-yP demonstrates remarkable durability for continuous electrolysis even at a large current density of 240 mA cm-2.