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High‐performance metal fluoride cathodes are crucial to design ultrahigh‐capacity lithium metal batteries for taking part in the next‐generation energy storage market. However, their insulating nature and sluggish reaction kinetics result in voltage hysteresis, low‐rate capability, and rapid capacity degradation. Herein, a generalizable one‐step melt synthesis approach is reported to construct hetero‐packing nanostructures of FeF3@C‐Asphalt nanocomposites, where ultrafine FeF3 nanoparticles are homogeneously covered by a high conductive carbon framework. By the electrochemical kinetics calculation and multiphysics simulations, this FeF3@C‐Asphalt nanocomposites consist of ultrafine nanoparticles and a constrained carbon framework, offering a high tap density (1.8 g cm−3), significantly improved conductivity, and enhanced charge pathways, and thereby enabling the fast electron transport, rapid ion migration, depressed electrode internal stress, and mitigated volume expansion. As a result, the optimized FeF3@C‐Asphalt cathode delivers a high capacity of 517 mAh g−1, high cyclic stability of 87.5% after 1000 cycles under 5 A g−1 (10 C), and excellent capacity retention of 77% from 0.5 A g−1 to 10 A g−1 (20 C, 250 mAh g−1). The work provides an easy‐to‐operate and low‐cost approach to accomplish high cyclic stability metal fluoride‐lithium batteries, which will guide the development of fast‐charging ultrahigh‐capacity cathode materials for the new energy industry. [ABSTRACT FROM AUTHOR]

Proprioception evaluated by the repetition performance of limbs' movement is an important indicator of sports rehabilitation. Since motion monitoring using wearable sensors is hampered by challenges in sensitivity, conformability, and stability, proprioception assessments still rely heavily on bulky apparatus. This work reports a bioinspired strain sensor with sensitivity‐enhanced structures based on strain redistribution to achieve proprioceptive training of joints, showing high sensitivity and stability even under large deformation. The sensing structure consists of units with different moduli and is independent of the sensing materials and sensors' shape, and thus can be universally applied to various devices. A new method of multi‐material 3D printing is developed to construct the complex substrates with heterogeneous moduli architecture and automatically fabricate the entire sensor. To fulfill effective proprioception exercise, the conformal deformation of printed sensors attached to joints during the whole stretch period is verified in computed tomography imaging, which indicates the output of sensors can precisely reflect the movement of joints. A complete recovery cycle of 4 weeks is demonstrated, during which an injured patient training with our skin‐attachable strain sensors restored his ability in limb control. This proprioceptive training paradigm with intelligent sensors paves the way to home‐based rehabilitation. [ABSTRACT FROM AUTHOR]

Periodic noise is a well-known problem in seismic exploration, caused by power lines, pump jacks, engine operation, or other interferences. It contaminates seismic data and affects subsequent processing and interpretation. The conventional methods to attenuate periodic noise are notch filtering and some model-based methods. However, these methods either simultaneously attenuate noise and seismic events around the same frequencies, or need expensive computation time. In this work, a new method is proposed to attenuate periodic noise based on sparse representation. We use a noise dictionary to sparsely represent periodic noise. The noise dictionary is constructed based on ambient noise. An advantage of our method is that it can automatically suppress monochromatic periodic noise, multitoned periodic noise and even periodic noise with complex waveforms without pre-known noise frequencies. In addition, the method does not result in any notches in the spectrum. Synthetic and field examples demonstrate that our method can effectively subtract periodic noise from raw seismic data without damaging the useful seismic signal. [ABSTRACT FROM AUTHOR]

Identification of different modes of Rayleigh waves is essential in surface‐wave surveys. Multi‐mode Rayleigh waves can provide higher accuracy of the near‐surface structure than the fundamental mode alone. However, some modes or frequencies of Rayleigh waves may be absent in the vertical‐component seismic data. To complement the dispersion information, a method based on complex‐vector seismic data is proposed. We construct the complex vector by setting the radial component and vertical component as the real part and imaginary part, respectively. Then, high‐resolution linear Radon transform is used to obtain the multi‐mode Rayleigh‐wave dispersion image of the complex‐vector seismic data. Based on different dispersion characteristics of the radial and vertical components, the dispersion images of the complex–vector seismic data show better performance against interferences and mode misidentification. Synthetic and field examples demonstrate advantages of the complex‐vector method over the traditional vertical‐component method in spectral bands and dispersion curve mode identification. Therefore, a more robust and accurate near‐surface S‐wave velocity structure can be expected compared to the traditional vertical‐component Rayleigh‐wave method. [ABSTRACT FROM AUTHOR]

Featured Application: The proposed method is applicable for surface-wave extraction on X component in multicomponent seismic exploration. This method has application potential for the separation of PS-waves and surface waves whose frequencies and velocities are close. It is essential to extract high-fidelity surface waves in surface-wave surveys. Because reflections usually interfere with surface waves on X components in multicomponent seismic exploration, it is difficult to extract dispersion curves of surface waves. To make matters worse, the frequencies and velocities of higher-mode surface waves are close to those of PS-waves. A method for surface-wave extraction is proposed based on the morphological differences between surface waves and reflections. Frequency-domain high-resolution linear Radon transform (LRT) and time-domain high-resolution hyperbolic Radon transform (HRT) are used to represent surface waves and reflections, respectively. Then, a sparse representation problem based on morphological component analysis (MCA) is built and optimally solved to obtain high-fidelity surface waves. An advantage of our method is its ability to extract surface waves when their frequencies and velocities are close to those of reflections. Furthermore, the results of synthetic and field examples confirm that the proposed method can attenuate the distortion of surface-wave dispersive energy caused by reflections, which contributes to extraction of accurate dispersion curves. [ABSTRACT FROM AUTHOR]

Prevention of brain injury in woodpeckers under high deceleration during the pecking process has been an intriguing biomechanical problem for a long time. Several studies have provided different explanations, but the function of the hyoid bone, one of the more interesting skeletal features of a woodpecker, still has not been fully explored. This paper studies the relationship between a woodpecker head’s response to impact and the hyoid bone. Based on micro-CT scanning images, the material point method (MPM) is employed to simulate woodpecker’s pecking process. The maximum shear stress in the brainstem (SSS) is adopted as an indicator of brain injury. The motion and deformation of the first cervical vertebra is found to be the main reason of the shear stress of the brain. Our study found that the existence of the hyoid bone reduces the SSS level, enhances the rigidity of the head, and suppresses the oscillation of the endoskeleton after impact. The mechanism is explained by a brief mechanical analysis while the influence of the material properties of the muscle is also discussed. [ABSTRACT FROM AUTHOR]

Rotational observation is essential for a comprehensive description of the ground motion, and can provide additional wave-field information. With respect to the three typical layered models in shallow engineering geology, under the assumption of linear small deformation, we simulate the 2-dimensional radial, vertical, and rotational components of the wave fields and analyze the different characteristics of Rayleigh wave dispersion recorded for the rotational and translational components. Then, we compare the results of single-component inversion with the results of multi-component joint inversion. It is found that the rotational component has wider spectral bands and more higher modes than the translational components, especially at high frequencies; the rotational component has better anti-interference performance in the noisy data test, and it can improve the inversion accuracy of the shallow shear-wave velocity. The field examples also show the significant advantages of the joint utility of the translational and rotational components, especially when a low-velocity layer exists. Rotational observation shall be beneficial for shallow surface-wave exploration. [ABSTRACT FROM AUTHOR]

Abstract: The super-graphene (SG) and super-square (SS) carbon nanotube network are built by the straight single-walled carbon nanotubes and corresponding junctions. The elastic buckling behaviors of these carbon nanotube networks under different boundary conditions are explored through the molecular structural mechanics method. The following results are obtained: (a) The critical buckling forces of the SG and SS networks decrease as the side lengths or aspect ratios of the networks increase. The continuum plate theory could give good predictions to the buckling of the SS network but not the SG network with non-uniform buckling modes. (b) The carbon nanotube networks are more stable structures than the graphene structures with less carbon atoms. [Copyright &y& Elsevier]

Abstract: Under hydrostatic pressure, the equivalent elastic moduli of a zigzag single-walled carbon nanotube (SWNT) are analytically determined by energy conservation, with the consideration of the covalent bond deformation. The theoretical predictions on the transverse mechanical properties of a zigzag SWNT agree reasonably well with those given by the molecular structures mechanics simulations and also the ab initio calculations. From the simple geometry calculation, the circumferential strain is about 2–3 times of the axial strain of a zigzag SWNT under hydrostatic pressure. The bulk modulus of a zigzag SWNT is found to be 3/7 times of its radial Young''s modulus. [Copyright &y& Elsevier]

Abstract: The fracture investigations of the planar lattices made of ductile cell walls are currently limited to bending-dominated hexagonal honeycomb. In this paper, the plastic zones of stretching-dominated lattices, including Kagome and triangular lattices, are estimated by analyzing their effective yield loci. The normalized in-plane yield loci of these two lattices are almost identical convex curves enclosed by 4 straight lines, which is almost independent of the relative density but is highly sensitive to the principal stress directions. Therefore, the plastic zones around the crack tip of Kagome and triangular are estimated to be quite different to those of the continuum solid and also hexagonal lattice. The plastic zones predictions by convex yield surfaces of both lattices are validated by FE calculations, although the shear lag region caused by non-local bending effect in the Kagome lattice enlarges the plastic zone in cases of small ratio of rp/l. [Copyright &y& Elsevier]

Abstract: The specific heat of the super carbon nanotube (ST) was investigated by the molecular structure mechanics method. At given temperature, it was found that the specific heat of the ST is a fixed value and is almost independent both of the length, diameter and of chirality of the ST. By comparing the influences of the chirality of the ST on its mechanical properties, electronic properties and thermal properties as well, we find that the chirality effects on the physical properties of STs can be neglected. This result may be regarded as a universal law for the physical properties of STs. [Copyright &y& Elsevier]

Abstract: The elastic buckling of super carbon nanotubes (STs) under compression and bending were studied by the molecular structure mechanics method. Under compression, the elastic buckling mode of the ST is similar to that of a cantilever column. However, the bending buckling mode of ST could transform from shell wall buckling to beam buckling as the length of ST increases. Therefore, the classical Euler formula could give good prediction both to the critical compression force for ST and to the critical bending force for very long STs. A phenomenological formula for the critical bending force of ST was given in this work, which could well predict the critical bending buckling of STs and bridge over the transformation of the bending buckling mode. Two types of chirality independent phenomena were found: first, the critical compression force carried by the unit carbon nanotube inside STs is independent of the chirality of STs; second, the critical bending force of ST’s is independent of the chirality of STs. [Copyright &y& Elsevier]