Developing cost-effective and sustainable catalysts with exceptional activity and selectivity is essential for the practical implementation of on-site H2O2 electrosynthesis, yet it remains a ...formidable challenge. Metal phosphide core-shell heterostructures anchored in carbon nanosheets (denoted as Ni@Ni2P/C NSs) are designed and synthesized via carbonization and phosphidation of the 2D Ni-BDC precursor. This core-shell nanostructure provides more accessible active sites and enhanced durability, while the 2D carbon nanosheet substrate prevents heterostructure aggregation and facilitates mass transfer. Theoretical calculations further reveal that the Ni/Ni2P heterostructure-induced optimization of geometric and electronic structures enables the favored adsorption of OOH* intermediate. All these features endow the Ni@Ni2P/C NSs with remarkable performance in 2e ORR for H2O2 synthesis, achieving a top yield rate of 95.6 mg L-1 h-1 with both selectivity and Faradaic efficiency exceeding 90% under a wide range of applied potentials. Furthermore, when utilized as the anode of an assembled gas diffusion electrode (GDE) device, the Ni@Ni2P/C NSs achieve in situ H2O2 production with excellent long-term durability (>32 h). Evidently, this work provides a unique insight into the origin of 2e ORR and proposes optimization of H2O2 production through nano-interface manipulation.
Sodium niobate (NaNbO3, NN)-based ferroelectric ceramics have been extensively studied owing to their antiferroelectric (AFE) nature. However, the dielectric properties of NN-based ceramics, which ...would be beneficial to capacitor devices, gain less research interest. In this study, (1−x)NaNbO3-xBi(Mg0.5Ti0.5)O3 (NN-xBMT, x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) ferroelectric ceramics were manufactured by a traditional solid state method. Structure and dielectric/ferroelectric properties were studied in detail by X-ray diffraction, dielectric spectrum as well as polarization-electric field hysteresis loops. All ceramic samples show an AFE P phase in the doping range. As x increases, the grain size of studied compositions gradually decreases from 5.36 μm in x = 0 to 2.05 μm in x = 0.05. In addition, the incorporation of BMT plays a regulatory role to the Curie temperature TC of ceramic samples, which decreases almost linearly from 375 °C x = 0 to 216 °C x = 0.05 at a rate of 33 °C/1 at. %. However, the degree of diffusion for each composition does not change significantly. More importantly, ultra-high thermally stable dielectric responses in a wide temperature range are obtained in NN-xBMT. Especially in x = 0.03, its permittivity is around 500 at room temperature and shows a variation less than 4.4% from 30 to 150 °C. Our results may have some guiding significance for the preparation of NN-based ceramics with specific TC, and are significantly important for capacitor applications requiring a wide temperature range stability.
The yellow drum Nibea albiflora is a marine fish of great economic value in China. Despite efforts to improve yields, aquaculture of this species has been hindered by increases in winter-related ...mortalities associated with cold temperatures and associated natural fasting periods. To better understand the molecular mechanisms that regulate stress responses in yellow drum during periods of cold and starvation, the effect of these stresses on the liver was investigated by performing comparative analyses among fish subjected to different temperatures and feeding strategies. The experiment lasted for 22 d and involved 4 groups: one fed group (control) and one fasted group at 16°C, and one fed group and one fasted group at 8°C. Our results showed that all stress-treated groups exhibited body weight loss during the experiment, demonstrating that both cold stress and fasting caused growth inhibition, but only the fish in the fasted group at 16°C showed a loss in the liver/body ratio, suggesting that starvation can cause mass loss in the liver while cold stress can result in mass loss in both liver and other tissues. Histological alterations were observed in the liver cells from stress-treated groups, also indicating mass loss in the liver during cold stress and starvation. Transcriptomic analysis showed that genes related to the metabolism of carbohydrates, lipids and amino acids were the most enriched differentially expressed genes during the challenge conditions. These findings can help reveal molecular mechanisms regulating the stress responses of yellow drum exposed to cold and starvation.
Relaxor ferroelectrics (RFEs), which possess high maximum polarization (Pmax), low remnant polarization (Pr) and coercive field (Ec), are good candidates for the applications in electrostrictive ...devices. Compared to lead-free RFEs, lead-containing RFEs possess higher Pmax, due to the contribution by lead ions. However, relatively low breakdown strength (BDS) in lead-containing RFEs becomes a bottleneck for exploring the electrostrictive properties especially at higher electric field. In this work, we synthesized (1−x)0.5573Pb(Mg1/3Nb2/3)O3-0.4427PbTiO3-xBa(Zn1/3Nb2/3)O3 (1−x)PMNT-xBZN, x = 0.1725, 0.1925, 02125 and 0.2325 RFE ceramics with addition of Li2O-B2O3-SiO2 glass additives (2 wt%) and studied the BDS and dielectric/ferroelectric properties in detail. It was found that an enhancement of BDS from ∼120 kV cm−1 for undoped samples to ∼160 kV cm−1 for glass-doped samples. Higher Pmax, lower Pr and lower Ec were simultaneously obtained in x = 0.1725, 0.1925 and 02125 compositions, suggesting improved ferroelectric properties. Purely electrostrictive strains with levels from 0.147% to 0.069% were obtained in glass-doped compositions when x increases from 0.1725 to 0.2325 at 30 °C, and more than 40% strain response were maintained when temperature is increased to 130 °C. This work proves the effectiveness of glass additives to enhance BDS and improve ferroelectric properties in lead-based (1−x)PMNT-xBZN RFE ceramics.
To investigate the feasibility and effect of human amniotic membrane in prevention of tendon adhension after tendon sheat defect repair.
The amniotic membrane in size of 1.5 cm x 1.0 cm was harvested ...from human placenta which was voluntary donated from maternal after cesarean. Forty healthy male Leghorn chicken (aged 3-6 months) were selected, weighing (1.86 +/- 0.04) kg. The model of flexor digitorum profundus tendon and tendon sheath defects was established at the third toe. After repair of the flexor digitorum profundus tendon, the human amniotic membrane was used to repair the tendon sheath defect in the right foot (group A), but tendon sheath defect was not repaired in the left foot (group B) . At 1, 2, 4, and 6 weeks after operation, the gross and histological observations were done; the degree of tendon adhesions was graded according to Tang's tendon adhesion general observation grading standards; and the biomechanical properties (tendon slip length and total flexion angle) were tested.
All animals sur
People's life and production activities are directly or indirectly affected by the weather. It is very necessary to accurately and quickly predict weather conditions. At present, the weather ...prediction system needs a series of sensors and manual assistance, but it cannot be arranged in high density due to high cost, which leads to inaccurate weather prediction. Computer vision technology can classify weather conditions through images, which reduces the cost and can be arranged in high density to ensure the accuracy of weather prediction. Because the training and reasoning of traditional p Convolutional Neural Network has very large energy consumption, while Spiking Neural Network has the characteristics of ultra-low energy consumption, which can further reduce the energy cost. In this paper, a shallow Spiking Neural Network for weather classification is constructed, which is trained and tested on a dataset containing four categories (cloudy, rainy, sunny and sunrise). Experiments show that the classification accuracy of the model is 93.45%, which is higher than that of the Convolutional Neural Network based on vgg19. In addition, the computational complexity of Spiking Neural Network and Convolutional Neural Network are analyzed to show the advantages of Spiking Neural Network in energy consumption.
PDF
