A novel framework for three-dimensional electrical impedance tomography reconstruction of maize ear via feature reconfiguration and residual networks.

Electrical impedance tomography (EIT) provides an indirect measure of the physiological state and growth of the maize ear by reconstructing the distribution of electrical impedance. However, the two-dimensional (2D) EIT within the electrode plane finds it challenging to comprehensively represent the spatial distribution of conductivity of the intact maize ear, including the husk, kernels, and cob. Therefore, an effective method for 3D conductivity reconstruction is necessary. In practical applications, fluctuations in the contact impedance of the maize ear occur, particularly with the increase in the number of grids and computational workload during the reconstruction of 3D spatial conductivity. These fluctuations may accentuate the ill-conditioning and nonlinearity of the EIT. To address these challenges, we introduce RFNetEIT, a novel computational framework specifically tailored for the absolute imaging of the three-dimensional electrical impedance of maize ear. This strategy transforms the reconstruction of 3D electrical conductivity into a regression process. Initially, a feature map is extracted from measured boundary voltage via a data reconstruction module, thereby enhancing the correlation among different dimensions. Subsequently, a nonlinear mapping model of the 3D spatial distribution of the boundary voltage and conductivity is established, utilizing the residual network. The performance of the proposed framework is assessed through numerical simulation experiments, acrylic model experiments, and maize ear experiments. Our experimental results indicate that our method yields superior reconstruction performance in terms of root-mean-square error (RMSE), correlation coefficient (CC), structural similarity index (SSIM), and inverse problem-solving time (IPST). Furthermore, the reconstruction experiments on maize ears demonstrate that the method can effectively reconstruct the 3D conductivity distribution.

Construction of Single-Atom Catalysts for N, O Synergistic Coordination and Application to Electrocatalytic O2 Reduction.

Replacing expensive platinum oxygen reduction reaction (ORR) catalysts with atomically dispersed single-atom catalysts is an effective way to improve the energy conversion efficiency of fuel cells. Herein, a series of single-atom catalysts, TM-N2O2Cx (TM=Sc-Zn) with TM-N2O2 active units, were designed, and their catalytic performance for electrocatalytic O2 reduction was investigated based on density functional theory. The results show that TM-N2O2Cx exhibits excellent catalytic activity and stability in acidic media. The eight catalysts (TM=Sc, Ti, V, Cr, Mn, Fe, Co, and Ni) are all 4e- reaction paths, among which Sc-N2O2Cx, Ti-N2O2Cx, and V-N2O2Cx follow dissociative mechanisms and the rest are consistent with associative mechanisms. In particular, Co-N2O2Cx and Ni-N2O2Cx enable a smooth reduction in O2 at small overpotentials (0.44 V and 0.49 V, respectively). Furthermore, a linear relationship between the adsorption free energies of the ORR oxygen-containing intermediates was evident, leading to the development of a volcano plot for the purpose of screening exceptional catalysts for ORR. This research will offer a novel strategy for the design and fabrication of exceptionally efficient non-precious metal catalysts on an atomic scale.

Densely populated tiny RuO2 crystallites supported by hierarchically porous carbon for full acidic water splitting.

The exploitation of highly active bifunctional electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in acidic media has been a subject receiving immense interest. However, the existing catalysts usually suffer from low catalytic efficiency and poor corrosion resistance under acidic conditions. Herein, we report a facile molten salt method to fabricate ruthenium dioxide nanoparticles supported by hierarchically porous carbon (RuO2/PC) as a bifunctional electrocatalyst for full water splitting under strong acidic conditions. The formation of a densely populated nanocrystalline RuO2/carbon heterostructure helps expose catalytic sites, accelerates the mass transfer rate, and further enhances the acid resistance of RuO2 nanoparticles. The as-synthesized RuO2/PC consequently exhibits superior catalytic performance for the OER with an overpotential of 181 mV upon 10 mA cm-2 compared to that of the commercial RuO2 (343 mV) and a comparable performance to Pt/C for the HER (47.5 mV upon 10 mA cm-2) in 0.5 M H2SO4. The RuO2/PC shows promising stability with little degradation over ∼24 h. Impressively, the water electrolyzer based on RuO2/PC shows an overpotential of 326 mV at 10 mA cm-2, much lower than that of the electrolyzer based on the combination of Pt/C and RuO2 (400 mV), indicating its great potential towards practical application.

Bipolar fluorinated covalent triazine framework cathode with high lithium storage and long cycling capability.

Organic materials with adjustable structures and wide sources are expected to become potential candidates for commercial cathodes of lithium-ion batteries (LIBs). However, most organic materials have unstable structures, poor conductivity, and are easily soluble in electrolytes, resulting in unsatisfactory lithium storage performance. Covalent-organic frameworks have attracted extensive attention due to their stable frame structures, adjustable pore structures and functionalized official groups. Herein, a fluorinated covalent triazine framework (FCTF) is synthesized by a simple ion-thermal method. Compared with the fluorine-free covalent triazine frameworks (CTFs), the introduction of fluorine improves the lithium storage performance of CTF. When used as a cathode for lithium ion batteries, FCTF can retain a reversible capacity of 125.6 mA h g-1 after 200 cycles at a current density of 100 mA g-1. Besides, it also delivers 106.3 mA h g-1 after 400 cycles at a current density of 200 mA g-1 with 0.03% decrease per cycle (from 40 to 400 cycles).

Efficient electrocatalytic reduction of carbon dioxide by metal-doped ß12-borophene monolayers.

Electrochemical reduction of CO2 to value-added chemicals and fuels shows great promise in contributing to reducing the energy crisis and environment problems. This progress has been slowed by a lack of stable, efficient and selective catalysts. In this paper, density functional theory (DFT) was used to study the catalytic performance of the first transition metal series anchored TM-Bß12 monolayers as catalysts for electrochemical reduction of CO2. The results show that the TM-Bß12 monolayer structure has excellent catalytic stability and electrocatalytic selectivity. The primary reduction product of Sc-Bß12 is CO and the overpotential is 0.45 V. The primary reduction product of the remaining metals (Ti-Zn) is CH4, where Fe-Bß12 has the minimum overpotential of 0.45 V. Therefore, these new catalytic materials are exciting. Furthermore, the underlying reaction mechanisms of CO2 reduction via the TM-Bß12 monolayers have been revealed. This work will shed insights on both experimental and theoretical studies of electroreduction of CO2.

Electrochemical behavior and voltammetric determination of paracetamol on Nafion/TiO2-graphene modified glassy carbon electrode.

The TiO(2)-graphene (TiO(2)-GR) nanocomposite for paracetamol electrochemical sensing is described. The electrochemical behavior of paracetamol at the Nafion/TiO(2)-GR composite film modified glassy carbon electrode (GCE) was investigated by cyclic voltammetry. The results showed that the incorporation of TiO(2) nanoparticles with graphene significantly enhanced the electrochemical reactivity and voltammetric response of paracetamol. In addition, Nafion acts as an effective solubilizing agent and antifouling coating in the fabrication of the modified electrode. This electrochemical sensor exhibits excellent analytical performance for paracetamol detection at physiological pH with detection limit of 2.1×10(-7) M, linear range of 1-100 µM and reproducibility of 3.6% relative standard deviation.

Hydrothermal preparation and electrochemical sensing properties of TiO(2)-graphene nanocomposite.

A facile hydrothermal method has been developed and shown to be effective for the preparation of TiO(2)-graphene nanocomposite. The as-prepared nanocomposite was characterized using FT-IR spectroscopy, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The TiO(2)-graphene modified glassy carbon electrode (GCE) exhibited remarkable electron transfer kinetics and electrocatalytic activity toward the oxidation of dopamine (DA). Furthermore, the oxidation of common interfering agent such as ascorbic acid (AA) was significantly suppressed at this modified electrode, which resulted in good selectivity and sensitivity for electrochemical sensing of DA. These results demonstrate that the TiO(2)-graphene hybrid material has promising potential applications in electrochemical sensors and biosensors design.