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Electronic skins are expected to replicate a human‐like tactile sense, which significantly detects surface information, including geometry, material, and temperature. Although most texture features can be sensed in the horizontal direction, the lack of effective approaches for detecting vertical properties limits the development of artificial skin based on tactile sensors. In this study, an all‐printed finger‐inspired tactile sensor array is developed to realize the 3D detection and reconstruction of microscale structures. A beam structure with a suspended multilayer membrane is proposed, and a tactile sensor array of 12 units arranged in a dual‐column layout is developed. This architecture enables the tactile sensor array to obtain comprehensive geometric information of micro‐textures, including 3D morphology and clearance characteristics, and optimizes the 3D reconstruction patterns by self‐calibration. Moreover, an innovative screen‐printing technology incorporating multilayer printing and sacrificial‐layer techniques is adopted to print the entire device. In additon, a Braille recognition system utilizing this tactile sensor array is developed to interpret Shakespeare's quotes printed in Grade 2 Braille. The abovementioned demonstrations reveal an attractive future vision for endowing bioinspired robots with the unique capability of touching and feeling the microscale real world and reconstructing it in the cyber world. [ABSTRACT FROM AUTHOR]

This paper proposes an operation modal analysis (OMA)-based approach to obtain a transformer's mechanical condition from vibrations during the transformer's transient processes, such as short-circuit and power-off conditions. Such processes generate a short transient vibration response, which yields a spectrum with poor frequency resolution. Vibration before the transient process could be included to increase the signal length; however, this would introduce a forced vibration component into the spectrum, making it challenging to distinguish the modal frequencies. To overcome these problems, a time–frequency analysis-based algorithm is proposed to extract the modal frequency spectrum from the vibration signal with the high-frequency resolution, providing clearer insight into the mechanical condition of the transformer. A faulty-state indicator is then proposed based on the similarity between the extracted modal spectrum and the initial modal spectrum obtained under a healthy state. To validate the proposed method, laboratory experiments were conducted under short-circuit and power-off conditions. Two mechanical faults—the looseness of the winding clamping and winding deformation—are introduced. The results show that both faults will cause variations in the modal frequency spectrum, leading to significant decreases in the indicator value. In summary, the proposed method can effectively evaluate a transformer's mechanical condition in an OMA setting. [ABSTRACT FROM AUTHOR]

Two-phase rotating detonation ramjets are considered to be suitable for aerospace applications due to their high thermodynamic cycle efficiency. These engines have an extremely complex internal flow field, in which the liquid fuel undergoes physical and chemical processes such as fragmentation, evaporation, mixing, and combustion; these processes also interact with detonation waves that have significant gradients. This makes it difficult to simulate a three-dimensional (3D) full-process rotating detonation combustion chamber. Here, based on the Euler–Lagrangian simulation method, a 3D numerical combustion chamber was simulated using kinetic theory and the constant thermal physical property parameter (TPPP) calculation method. The accuracy of these methods was then compared with the existing experimental results and theoretical values. Calculating the TPPPs using kinetic theory brought about a relatively high-pressure peak and detonation wave temperature; the detonation wave profile was also finer and more precise. The detonation wave propagation velocity of the two-phase detonation is estimated to be about 60% of the theoretical gas-phase CJ velocity. The calculation method of physical parameters has relatively little influence on the engine's operating frequency and the detonation wave's propagation velocity but has a more significant influence on the peak pressure. Constant TPPPs can be used when the Kelvin–Helmholtz–Rayleigh–Taylor model with insufficient precision is used to consider the breakup of droplets and leads to the acceleration of the propagation speed of two-phase detonation waves. [ABSTRACT FROM AUTHOR]

Portulaca oleracea is an important and widely distributed medicinal and edible plant that has great economic value in the medical and food industries. We sequenced the complete chloroplast (cp) genome of P. oleracea,whichis156,533 bp in length, including a pair of inverted repeats (IRs) of 25,501 bp separated by a large single copy (LSC) region of 87,436 bp and a small single copy (SSC) region of 18,095 bp. The genome contains 85 protein-coding genes, 37 transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. There are 40 repeat units and 111 simple sequence repeats (SSRs) in the genome. We also carried out complete cp genome comparison with other Caryophyllales species. The size, gene content, and structural organisation of P. oleracea are relatively conserved, but the genes ycf1 and ycf2 have larger introns. The simple sequence repeats (SSR) in the introns of ycf3, ycf1, atpB, rrn23 and ndhH have significant polymorphism. Comparisons of IR boundaries among 8 Caryophyllales species showed contraction and expansion. The complete cp genome sequence will contribute to a better understanding of the evolutionary mode of the cp genome and to the development of new markers for Caryophyllales classification. [ABSTRACT FROM AUTHOR]

Two-phase rotating detonation ramjets are considered to be suitable for aerospace applications due to their high thermodynamic cycle efficiency. These engines have an extremely complex internal flow field, in which the liquid fuel undergoes physical and chemical processes such as fragmentation, evaporation, mixing, and combustion; these processes also interact with detonation waves that have significant gradients. This makes it difficult to simulate a three-dimensional (3D) full-process rotating detonation combustion chamber. Here, based on the Euler–Lagrangian simulation method, a 3D numerical combustion chamber was simulated using kinetic theory and the constant thermal physical property parameter (TPPP) calculation method. The accuracy of these methods was then compared with the existing experimental results and theoretical values. Calculating the TPPPs using kinetic theory brought about a relatively high-pressure peak and detonation wave temperature; the detonation wave profile was also finer and more precise. The detonation wave propagation velocity of the two-phase detonation is estimated to be about 60% of the theoretical gas-phase CJ velocity. The calculation method of physical parameters has relatively little influence on the engine's operating frequency and the detonation wave's propagation velocity but has a more significant influence on the peak pressure. Constant TPPPs can be used when the Kelvin–Helmholtz–Rayleigh–Taylor model with insufficient precision is used to consider the breakup of droplets and leads to the acceleration of the propagation speed of two-phase detonation waves. [ABSTRACT FROM AUTHOR]