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We developed an accurate and efficient machine learning potential with DFT accuracy and applied it to the silicon dry/wet oxidation process to investigate the underlying physics of thermal oxidation of silicon (001) surfaces. The accuracy of the potential was verified by comparing the melting point and structural properties of silicon, the structural properties of a-SiO2, and the adsorption properties on the silicon surface with experiment and DFT data. In subsequent thermal oxidation simulations, we successfully reproduced the accelerated growth phenomenon of the wet oxidation in the experiment, discussed the oxide growth process in detail, and elucidated that the accelerated growth is due to hydrogen in the system that both enhances the adsorption of oxygen on the silicon surface and promotes the migration of oxygen atoms. Finally, we annealed the oxidized structure, counted the defect information in the structure before and after annealing, and analyzed the defect evolution behavior during the annealing process. [ABSTRACT FROM AUTHOR]

Herein, the efficiently high‐power pulsed Raman lasers with wavelength above 2.1 μm are experimentally demonstrated relying on the stimulated Raman scattering. A tailored high‐power noise‐like pulse (NLP) fiber laser system centered at ≈1953 nm with a maximum output power of ≈10.9 W is served as the pump source. By directly pumping a section of highly Ge‐doped silica fiber, the first pulsed Raman laser (centered at≈2139 nm) and the second pulsed Raman laser (centered at ≈2353 nm) with maximum output powers of ≈3.8 and ≈0.25 W are obtained, respectively, which represent the highest output powers of NLP at these wavelength regions, to the best of knowledge. Moreover, a high spectral purity of ≈94.3% of the first Raman laser is obtained, which indicates the significantly potential application of NLP in pulsed Raman laser. The midinfrared NLP fiber laser source will have potential applications in transparent polymer materials processing and midinfrared spectroscopy. [ABSTRACT FROM AUTHOR]

The metal–insulator transition (MIT) of vanadium dioxide (VO2), which involves significant changes in electrical, optical, and other properties, has attracted widespread attention. Here, we report a triboelectric nanogenerator (TENG)-based self-powered VO2 phase transition. With the TENG-induced ionic gel gating, the hydrogen ion insertion/detachment in the VO2 lattice can be modulated at room temperature to cause phase transitions that control light transmittance. The phase transition behavior is characterized by X-ray diffraction and Raman spectroscopy. Under the continuous power supply from TENG, the X-ray diffraction peak of VO2 shifts, and the Raman intensities of characteristic peaks decrease, accompanied by a color change from brown to translucent. The electrical conductivity undergoes a significant change by two orders of magnitude and persists overnight, indicating an excellent duration of the phase transition. In addition, a raindrop TENG-induced VO2 phase transition is demonstrated. The infrared transmittance of VO2 is decreased dramatically by 28.1% due to the phase transition, achieving a heat preservation effect that holds promise for adaptive thermal insulation in smart windows during rainfall through raindrop power generation. This work has realized the TENG-based self-powered VO2 phase transition, holding significant application potential in smart homes. [ABSTRACT FROM AUTHOR]

Fipronil is a widely used insecticide. Exposure of humans to fipronil can cause harmful health effects. The aim of the present work is to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the rapid detection of fipronil and its metabolites in eggs and environmental matrices (soil, feed, and chicken feed bags). Solvent extraction was performed with a mixture including water, acetonitrile, and sodium chloride, followed by purification using a solid-phase extraction column. The LC separation was accomplished on a C18 column, and the detection was performed with a triple quadrupole mass spectrometer using electrospray ionization in multiple reaction monitoring (MRM) mode. The results showed a good linear relationship between fipronil and its metabolites in the range of 0.01 to 20 ng/mL, and the linear correlation coefficients ([R.sup.2]) were all greater than 0.999. The detection and quantification limits of the method for all analytes were 0.01 and 0.05 ng/mL, respectively. The precision expressed as coefficients of variation (n = 3) for assay of fipronil and its metabolites ranged from 8.4% to 13.2% at three levels (0.1 ng/mL, 1 ng/mL, and 10 ng/mL). The recoveries ranged from 81.3% to ~119.5%. Finally, we successfully employed the method to a case of fipronil contamination, and found residues of fipronil and its metabolites in eggs and the environmental matrix., Fipronil is a type of benzopyrazole insecticide developed in 1987 by Bayer Scientific Crops Co. Ltd. (1), and is widely used to control crop pests in vegetables, rice, tobacco, cotton, [...]

Tapered fiber (TF) and D-shaped fiber (DF) are two types of widely investigated devices in facilitating evanescent-field interactions with external materials. Although they have been found to be particularly useful in various ultrafast regimes, to date there is still no clear or systematic investigation on their local nonlinearities as well as the exerted influences on ultrafast behaviors. Herein, we present such thorough investigation through local nonlinearity engineering on TF and then in contrast with a DF as a reference. Optically deposited black phosphorus quantum dots (BPQDs) are used for saturable absorption. The nanometer-scale extremely small sizes of the BPQDs helpfully eliminate size-induced uncertainties or distortions during both device fabrication and the latter light–matter interaction. For the TF, in the experiment, it is found that the local nonlinear effect starts to be rather appreciable as the TF shrinks to a moderate thickness. Remarkably in comparison, the local nonlinearity of the DF itself can even be neglected reasonably, but after coating with BPQDs, it possesses a much larger modulation depth than any of the used BPQDs-coated TFs with different thicknesses/lengths. Further, we theoretically analyze the related locally nonlinear effects and reveal, for the first time, the direct origin of saturable absorption with evanescent-field-based general structures.

This paper presents a multi-scale numerical method to study the electrolyte material BaZrO3 (BZO) and gives numerical implementations and results. At the microscopic level, molecular dynamics (MD) is used to model the atomic structure of BZO. At the macroscopic level, the finite element method is used for loading and numerical solution. To bridge the microscopic and macroscopic scales, the concept of coarse-grained and coupled algorithms was used to establish a relationship between the atomic mass and the number of nodes in a continuous medium by means of a weighted residual method. This approach takes into account the anisotropy of the atomic structure of BZO and determines an intrinsic nature law through detailed modelling of the microstructure. We first describe the principle of the Atom-to-Continuum (AtC) multiscale approach and verify the accuracy of the multiscale calculation method by comparing the stress–strain curves of BZO with a central crack under the AtC method and MD simulations. The mechanical response of the crack under macroscopic and microscopic calculations is then observed and discussed by combining it with finite element software. Under the finite element simulations, the crack extends forward in a cleavage manner, while in the MD simulations the results show a clear directional dependence: the (100) surface fracture involves in-plane slip, with the crack propagating forward perpendicular to the plane between Zr and O; in the (110) surface the crack is unstable as it extends, resulting in a zigzag crack extension path, with the final crack remaining in the same direction as the initial direction remains the same. Our study not only reveals the fracture mechanism of perovskite oxide BZO but also presents a multi-scale approach that allows for large-scale calculations, providing a new way of studying the material design and applications. [ABSTRACT FROM AUTHOR]

Dislocations are important for their effects on the chemical, electrical, magnetic, and transport properties of oxide materials, especially for electrochemical devices such as solid fuel cells and resistive memories, but these effects are still under-studied at the atomic level. We have developed a quantum mechanical/molecular mechanical (QM/MM)-based multiscale simulation program to reveal the diffusion properties of protons on 〈100〉 edge dislocations in BaZrO3 perovskite oxide. We find that the large free space and the presence of hydrogen bonds in the dislocation core structure lead to significant trapping of protons. The diffusion properties of protons in dislocation cores were investigated, and no evidence of pipeline diffusion was found from the calculated migration energy barriers, which not only did not accelerate ion diffusion but rather decreases the conductivity of ions. The proton diffusion properties of Y-doped BaZrO3 (BZY), with a dislocation core structure (BZY-D) and with a grain boundary structure (BZY-GB) were also compared. In all three structures, local lattice deformation occupies an essential part in the proton transfer and rotation processes. The change in bond order is calculated and it is found that the interaction with oxygen and Zr ions during proton transfer and rotation controls the energy barrier for local lattice deformation of the O–B–O motion, which affects the proton diffusion in the structure. Our study provides insight into proton diffusion in dislocations in terms of mechanical behavior, elucidates the origin of the energy barrier associated with proton diffusion in dislocations, and provides guidance for the preparation and application of proton conductors. [ABSTRACT FROM AUTHOR]

Tapered fiber (TF) and D-shaped fiber (DF) are two types of widely investigated devices in facilitating evanescent-field interactions with external materials. Although they have been found to be particularly useful in various ultrafast regimes, to date there is still no clear or systematic investigation on their local nonlinearities as well as the exerted influences on ultrafast behaviors. Herein, we present such thorough investigation through local nonlinearity engineering on TF and then in contrast with a DF as a reference. Optically deposited black phosphorus quantum dots (BPQDs) are used for saturable absorption. The nanometer-scale extremely small sizes of the BPQDs helpfully eliminate size-induced uncertainties or distortions during both device fabrication and the latter light–matter interaction. For the TF, in the experiment, it is found that the local nonlinear effect starts to be rather appreciable as the TF shrinks to a moderate thickness. Remarkably in comparison, the local nonlinearity of the DF itself can even be neglected reasonably, but after coating with BPQDs, it possesses a much larger modulation depth than any of the used BPQDs-coated TFs with different thicknesses/lengths. Further, we theoretically analyze the related locally nonlinear effects and reveal, for the first time, the direct origin of saturable absorption with evanescent-field-based general structures. [ABSTRACT FROM AUTHOR]

In the era of Internet of Things (IoT) and Artificial Intelligence (AI), sensors have become an integral part of intelligent systems. Although the traditional sensing technology is very mature in long‐term development, there are remaining defects and limitations that make it difficult to meet the growing demands of current applications, such as high‐sensitivity detection and self‐supplied sensing. As a new type of sensor, array triboelectric nanogenerators (TENG)‐based tactile sensors can respond to wide dynamic range of mechanical stimuli in the surrounding environment and converting them into quantifiable electrical signals, thus realizing real‐time self‐supplied tactile sensing. The array structure allows for fine delineation of the sensing area and improved spatial resolution, resulting in accurate localization and quantification of the detected tactile signals, and have been widely used in wearable devices, smart interaction, medical and health detection, and other fields. In this paper, the latest research progress of functional tactile sensors based on arrayed triboelectric nanogenerators is systematically reviewed from the aspects of working mechanism, material selection, material processing, structural design, functional integration, and application. Finally, the challenges faced by arrayed triboelectric tactile sensors are summarized with a view to providing inspiration and guidance for the future development of tactile sensors. [ABSTRACT FROM AUTHOR]

This paper presents a multi-scale numerical method to study the electrolyte material BaZrO3 (BZO) and gives numerical implementations and results. At the microscopic level, molecular dynamics (MD) is used to model the atomic structure of BZO. At the macroscopic level, the finite element method is used for loading and numerical solution. To bridge the microscopic and macroscopic scales, the concept of coarse-grained and coupled algorithms was used to establish a relationship between the atomic mass and the number of nodes in a continuous medium by means of a weighted residual method. This approach takes into account the anisotropy of the atomic structure of BZO and determines an intrinsic nature law through detailed modelling of the microstructure. We first describe the principle of the Atom-to-Continuum (AtC) multiscale approach and verify the accuracy of the multiscale calculation method by comparing the stress–strain curves of BZO with a central crack under the AtC method and MD simulations. The mechanical response of the crack under macroscopic and microscopic calculations is then observed and discussed by combining it with finite element software. Under the finite element simulations, the crack extends forward in a cleavage manner, while in the MD simulations the results show a clear directional dependence: the (100) surface fracture involves in-plane slip, with the crack propagating forward perpendicular to the plane between Zr and O; in the (110) surface the crack is unstable as it extends, resulting in a zigzag crack extension path, with the final crack remaining in the same direction as the initial direction remains the same. Our study not only reveals the fracture mechanism of perovskite oxide BZO but also presents a multi-scale approach that allows for large-scale calculations, providing a new way of studying the material design and applications. [ABSTRACT FROM AUTHOR]

Tribovoltaic nanogenerator (TVNG) is an emerging energy device with the advantages of direct current and high power density. At present, many TVNGs are based on single-crystal materials, which are expensive and fragile during structural processing. Here, a polysilicon-based TVNG for bearing in situ rotational speed sensing is developed, which has the same level of performance and lower cost compared to monocrystalline silicon. The defects in polysilicon can provide additional carriers, but the grain boundaries can suppress the transport process of carriers, resulting in almost the same electrical output as single crystals. The oiled sliding mode TVNG has an impressive durability of up to 1 million cycles. The friction coefficient of rolling mode TVNG is as low as 0.14. Based on rolling mode polysilicon TVNG, the tapered roller bearing, thrust ball bearing, and deep groove ball bearing are manufactured by cutting and engraving processes. Moreover, their short-circuit current and open-circuit voltage are linear with speed, and the fitting coefficient is as high as 0.99, providing favorable conditions for in situ rotational speed sensing. This work presents a structure-function integrated bearing design methodology, demonstrating the considerable potential of in situ sensing for intelligent components in the industrial Internet of Things., (© 2024 Wiley‐VCH GmbH.)