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This study utilized a plant-wearable sap flow sensor developed by a multidisciplinary team at Zhejiang University to monitor water distribution patterns in watermelon fruit stalks throughout their developmental stages. The dynamic rules of sap flow at different stages of fruit development were discovered: (1) In the first stage, sap flow into the fruit gradually halts after sunrise due to increased leaf transpiration, followed by a rapid increase post-noon until the next morning, correlating with fruit expansion. (2) In the second stage, the time of inflow sap from noon to night is significantly shortened, while the outflow sap from fruit is observed with the enhancement of leaf transpiration after sunrise, which is consistent with the slow fruit growth at this stage. (3) In the third stage, the sap flow maintains the diurnal pattern. However, the sap flow that inputs the fruit at night is basically equal to the sap flow that outputs the fruit during the day; the fruit phenotype does not change anymore. In addition, a strong correlation between the daily mass growth in fruit and the daily sap flow amount in fruit stalk was identified, validating the sensor's utility for fruit growth monitoring and yield prediction. [ABSTRACT FROM AUTHOR]

The resistive functional layer in SrFeOx (SFO) topological phase transition (TPT) memristors is typically epitaxially grown on a perovskite bottom electrode and thus the bottom electrode plays an important role in the microstructure and resistive switching performance of the SFO functional layer. Unfortunately, the excessive diffusion of oxygen in the bottom electrode to SrFeOx causes uncontrollable distortion of the microstructure of the resistive functional layer, thereby compromising the overall device properties. In this study, SFO films were epitaxially grown on two different bottom electrodes of La0.7Sr0.3MnO3 (LSMO) and SrRuO3 (SRO) using pulsed laser deposition (PLD). The SFO memristor with a LSMO electrode exhibits excellent cycling stability, ON/OFF ratio, data retention, and endurance performance. In addition, the phase constituents, superlattice-like stripes and elemental valence states of SFO/LSMO and SFO/SRO hetero-structures were characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy, respectively. Furthermore, the oxygen migration free energy barriers of the bottom electrodes in the two devices were calculated by first-principles. All the above research results indicate that the LSMO electrode, being less prone to diffuse oxygen ions, significantly contributes to the superior structural stability and enhanced performance of the SFO/LSMO heterostructure. Finally, the energy band structures and Schottky barriers between BM-SFO and the top electrode of Au and the bottom electrode of LSMO were analyzed by ultraviolet photoelectron spectroscopy and ultraviolet-visible spectroscopy, which provide experimental insights into explaining its conductive mechanism. [ABSTRACT FROM AUTHOR]

The stability of W–C compounds (WC)-type ReC has been controversial for many years. Here, based on ab initio algorithm, we systematically searched for stable structures in the rhenium–carbon (Re–C) system at 0–300 gigapascal (GPa) pressure and analyzed the phase diagram within the pressure range. Only P63/mmc-Re2C, C2/m-Re3C, P21/m-Re4C, and C2/m-Re5C2 phases are found to be stable under 0–300 GPa, while WC-type ReC has high enthalpy and does not appear in the phase diagram. We also discussed the stability of WC-type ReC. Among these structures, C2/m-Re3C, P21/m-Re4C, and C2/m-Re5C2 are hitherto unknown structures, which could maintain dynamic and mechanical stability under ambient pressure. In addition, through the analysis of the structural and mechanical properties, P63/mmc-Re2C is the hardest metal among them with 31.5 GPa Vickers hardness at 0 GPa, and the metastable P 6 ¯ m 2 -Re5C3 has the second-highest hardness (29.3 GPa), both of which exceed the hardness of TiN (18.7 GPa), the commercial material used for cutting tools. The study of Re–C compounds with high hardness provides theoretical guidance for further experimental research. [ABSTRACT FROM AUTHOR]

Recent advances in speaker embeddings promote a great development of speaker diarization. However, determining 'who spoke when' in the meeting scenarios is still challenging due to similar speaker voices and unknown speaker quantity. In this paper, this research proposes enhanced discriminative features for speaker diarization, including discriminative speaker-specific features based on Siamese networks, and a speaker re-verification method. With Siamese architecture, SiamTDNN, this research first explores latent representations which is capable of modeling intra-class and inter-class differences between speakers, by training with audio pairs. Then, the re-verification method is introduced with a local-global strategy to identify speakers in a multi-person talking scene. Our method provides a novel speaker embedding with enhanced discriminative power for disambiguated speakers and achieves an elevated upper bound on the number of speakers. The proposed speaker embedding achieved an EER of 1.1% and a minDCF of 0.1192 on VoxCeleb1 for the speaker verification task. Extensive experiments on AiShell-4, ICSI, AMI and VoxConverse demonstrate the effectiveness of the proposed method with an average DER reduction of 3% and an RTF of 0.0792. [ABSTRACT FROM AUTHOR]

An ideal catalyst should have a relative hydrogen adsorption Gibbs free energy (ΔGH) close to zero [J. K. Nørskov, et al., J. Electrochem. Soc., 2005, 152, J23]. However, most of the known catalysts cannot reach this standard. Based on first-principles calculations, we studied the hydrogen evolution reaction (HER) catalytic performance of pristine and defect (including vacancy and heteroatom doping) structures in terms of its ΔGH. We found that the ΔGH values of Co-doped HfS2 and P-doped HfSe2 are extremely close to zero, even closer than that of Pt (111), indicating that they are excellent catalysts. Moreover, we found that the source of the HER catalytic performance of Co-doped HfS2 is the reduction of electron accumulation of the active site S atom. Our work provides two potential ideal catalysts and provides guidance for the experimental group to search for suitable catalysts. [ABSTRACT FROM AUTHOR]