Search

The undesirable capacity loss after first cycle is universal among layered cathode materials, which results in the capacity and energy decay. The key to resolving this obstacle lies in understanding the effect and origin of specific active Li sites during discharge process. In this study, focusing on Ah‐level pouch cells for reliability, an ultrahigh initial Coulombic efficiency (96.1%) is achieved in an archetypical Li‐rich layered oxide material. Combining the structure and electrochemistry analysis, we demonstrate that the achievement of high‐capacity reversibility is a kinetic effect, primarily related to the sluggish Li mobility during oxygen reduction. Activating oxygen reduction through small density would induce the oxygen framework contraction, which, according to Pauli repulsion, imposes a great repulsive force to hinder the transport of tetrahedral Li. The tetrahedral Li storage upon deep oxygen reduction is experimentally visualized and, more importantly, contributes to 6% Coulombic efficiency enhancement as well as 10% energy density improvement for pouch cells, which shows great potentials breaking through the capacity and energy limitation imposed by intercalation chemistry. [ABSTRACT FROM AUTHOR]

Grain size and weight are crucial yield-related traits in rice (Oryza sativa). Although certain key genes associated with rice grain size and weight have been successfully cloned, the molecular mechanisms underlying grain size and weight regulation remain elusive. Here, we identified a molecular pathway regulating grain size and weight in rice involving the MPS ONE BINDER KINASE ACTIVATOR-LIKE 1A–SERINE/THREONINE-PROTEIN KINASE 38–CYCLIN C (OsMOB1A–OsSTK38–OsCycC) module. OsSTK38 is a nuclear Dbf2-related kinase that positively regulates grain size and weight by coordinating cell proliferation and expansion in the spikelet hull. OsMOB1A interacts with and enhances the autophosphorylation of OsSTK38. Specifically, the critical role of the OsSTK38 S322 site in its kinase activity is highlighted. Furthermore, OsCycC, a component of the Mediator complex, was identified as a substrate of OsSTK38, with enhancement by OsMOB1A. Notably, OsSTK38 phosphorylates the T33 site of OsCycC. The phosphorylation of OsCycC by OsSTK38 influenced its interaction with the transcription factor KNOTTED-LIKE HOMEOBOX OF ARABIDOPSIS THALIANA 7 (OsKNAT7). Genetic analysis confirmed that OsMOB1A, OsSTK38, and OsCycC function in a common pathway to regulate grain size and weight. Taken together, our findings revealed a connection between the Hippo signaling pathway and the cyclin-dependent kinase module in eukaryotes. Moreover, they provide insights into the molecular mechanisms linked to yield-related traits and propose innovative breeding strategies for high-yielding varieties. Phosphorylation of the cell cycle regulator CYCLIN C by the ONE BINDER KINASE ACTIVATOR-LIKE 1A–SERINE/THREONINE-PROTEIN KINASE 38 kinase complex positively regulates grain size and weight by coordinating cell proliferation and expansion in the spikelet hull. [ABSTRACT FROM AUTHOR]

Gallium oxide (Ga2O3) usually fractures in the brittle form, and achieving large plastic deformability to avoid catastrophic failure is in high demand. Here, ε‐Ga2O3 thin films with columnar crystals and partial unoccupied Ga sites are synthesized, and it is demonstrated that the ε‐Ga2O3 at the submicron scale can be compressed to an ultra‐large plastic strain of 48.5% without cracking. The compressive behavior and related mechanisms are investigated by in situ transmission electron microscope nanomechanical testing combined with atomic‐resolution characterizations. The serrated plastic flow and large strain burst are two major deformation forms of ε‐Ga2O3 during compression, which are attributed to the dislocation nucleation and avalanches, formation of new grains, and amorphization. The ultra‐large compressive plasticity of ε‐Ga2O3 thin films at the submicron scale can inspire new applications of Ga2O3 in micro‐ or nano‐ electronic and optoelectronic devices, especially those that require impact resistance during processing or service. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation into shockwave and flame characteristics of compressed hydrogen released through various types of pressure relief devices (PRDs) for which data have not been previously reported. Burst disks and safety valves with different set pressure (P0) of 22–140 MPa were tested. Shockwave intensity/velocity spontaneous ignition/flame behavior was monitored by in-situ pressure/light sensors, respectively. Previous works have mostly focused on burst disks with low P0 (under 10 MPa), leaving safety valves and high-pressure burst disks uninvestigated. It was found that shockwave/spontaneous ignition behavior differs with PRD types. Spontaneous ignition occurs in all burst disk cases, along with an ignition/self-extinguishment/reignition process with relatively low P0, which has not been revealed previously. In contrast, none of the safety valves cause spontaneous ignition, resulting from the absence of shockwave due to lower overpressure values/rise rate during release. This suggests that shockwave formed by sudden release is the most dominant factor in spontaneous ignition. Also, the occurrence of self-extinguishment does not guarantee the absence of jet flame. This work provides a comprehensive database revealing shockwave and flame characteristics of hydrogen released through different PRDs, which offers basic data and theoretical support for the safety and risk assessment of high-pressure hydrogen facilities. [ABSTRACT FROM AUTHOR]

Density is an important parameter for both geological research and geophysical exploration. However, for model-driven seismic inversion methods, high-fidelity density inversion is challenging due to seismic wave traveltime insensitivity to density and crosstalk that density has with velocity. To circumvent the challenge of density inversion, some inversion methods treat density as a constant value or derive density from velocity through empirical equation. On the other hand, deep learning approaches are completely driven by data and have strong target-oriented characteristics, offering a new way to solve multiparameter coupling problems. Nevertheless, the accuracy of the inversion results of data-driven algorithms is directly related to the amount and diversity of the training data, and thus, they lack the universality of model-driven algorithms. To achieve accurate density inversion, we propose a simultaneous inversion algorithm for velocity and density that combines the advantages of data- and model- driven approaches: A neural network model (U-T), combining the U-net and Transformer architectures, is proposed to construct non-linear mappings between seismic data as inputs and the velocity and density as predictions. Next, the model-driven inversion algorithm uses the U-T prediction as the initial model to obtain the final accurate solution. In the model-driven module, envelope-based sparse constrained deconvolution is used to obtain full-band seismic data, while a variable dominant frequency full waveform inversion algorithm is used to perform multiscale inversion, ultimately leading to accurate inversion results of velocity and density. The performance of the algorithm on the Sigsbee2A and Marmousi models demonstrates its effectiveness. [ABSTRACT FROM AUTHOR]

Achieving simultaneous control over multiple functional properties, such as magnetic anisotropy, magnetoresistance, and metal-insulator transition, with atomic precision remains a major challenge for realizing advanced spintronic functionalities. Here, we demonstrate a unique approach to cooperatively tune these multiple functional properties in highly strained La0.7Sr0.3MnO3 (LSMO) thin films. By inserting varying perovskite buffer layers, compressively strained LSMO films transition from a ferromagnetic insulator with out-of-plane magnetic anisotropy to a metallic state with in-plane anisotropy. Remarkably, atomic-scale control of the buffer layer thickness enables precise tuning of this magnetic and electronic phase transformation. We achieve a colossal magnetoresistance tuning of 10,000% and an exceptionally sharp transition from out-of-plane to in-plane magnetic anisotropy within just a few atomic layers. These results demonstrate an unprecedented level of control over multiple functional properties, paving the way for the rational design of multifunctional oxide spintronic devices. [ABSTRACT FROM AUTHOR]

On-site hydrogen generation from ammonia decomposition is a promising technology to address the challenges of direct transportation and storage of hydrogen. The main problems with the existing support materials for ammonia decomposition catalysts are their high cost and time-consuming preparation process. In this work, ammonia decomposition catalysts consisting of in situ-formed nano-Ru particles supported on a naturally abundant mineral fiber, attapulgite (ATP), were proposed and studied. Also, 1 wt.% Ru was uniformly dispersed and anchored onto the surface of ATP fibers via the chemical method. We found that the calcination temperatures of the ATP support before the deposition of Ru resulted in little difference in catalytic performance, while the calcination temperatures of the 1Ru/ATP precursor were found to significantly influence the catalytic performance. The prepared 1 wt.% Ru/ATP catalyst (1Ru/ATP) without calcination achieved an ammonia conversion efficiency of 51% at 500 °C and nearly 100% at 600 °C, with the flow rate of NH3 being 10 sccm (standard cubic centimeter per minute). A 150 h continuous test at 600 °C showed that the 1Ru/ATP catalyst exhibited good stability with a degradation rate of about 0.01% h−1. The 1Ru/ATP catalyst was integrated with proton ceramic fuel cells (PCFCs). We reported that PCFCs at 650 °C offered 433 mW cm−2 under H2 fuel and 398 mW cm−2 under cracked NH3 fuel. The overall results suggest low-level Ru-loaded ATP could be an attractive, low-cost, and efficient ammonia decomposition catalyst for hydrogen production. [ABSTRACT FROM AUTHOR]

Near‐infrared (NIR) phosphor‐converted (pc) light‐emitting diodes (LEDs) are gaining popularity as smart NIR spectroscopy light sources. However, the low wall‐plug efficiency (WPE) of NIR pc‐LEDs has limited their applications due to the comprehensive properties of external quantum efficiencies (EQEs) and thermal stability for NIR phosphors. In this study, a simple strategy is presented to achieve high‐performance NIR phosphors by breaking the d–d parity forbidden transitions of Cr3+ in the garnet host by introducing asymmetric vibrations via lattice distortions. The achieved EQE is as high as 44% at room temperature and maintains >98% of the initial EQE at 150 °C, demonstrating excellent thermal stability. Notably, these NIR phosphors enable unprecedented NIR pc‐LEDs with a record WPE of 26% driven at 100 mA. Consequently, the application of NIR pc‐LEDs is expanded to new areas such as real‐time heart rate monitoring and fingerprint recognition. [ABSTRACT FROM AUTHOR]

In this paper, we presented an extended family of Miura-ori structures with programmable multi-step deformation via arraying and mirroring. We found that there is a competitive relationship between thickness gradient and structural gradient for these origami structures. Furthermore, we demonstrate that the multi-step deformation can be designed by altering the geometrical parametric and the order of these origami structures and the number of deformation stages will change with the change of the thickness gradient. Therefore, the current study can be used to construct novel origami metamaterials for engineering applications, such as energy absorbers for both light and heavy impacts. [ABSTRACT FROM AUTHOR]

Tianjin, one of the four municipalities in China, is the eastern gate of the capital city of Beijing and is of great socioeconomic importance. When rainstorms attack Tianjin, urban flooding often occurs due to the dense river network, well‐developed water system and flat terrain. In this study, the source analysis of water vapor in rainstorm processes in Tianjin during 2012–2020 is conducted based on the moisture source attribution method, and the PyTrajector and HYSPLIT softwares. Then, the evolution characteristics of rainstorms in Tianjin are investigated. The results show that the rainstorm water‐vapor sources in Tianjin city can be roughly divided into four directions. The west and southwest directions are the main source, which contribute about 89% of the water vapor to the rainstorms. For heavy rainstorm, the water vapor from the southwest direction contributes about 60%, which is larger than that of rainstorm. The southwest direction is the main water vapor source of heavy rainstorm in Tianjin and has the main effect on the water vapor fluctuations during heavy rainstorm. For the more hazardous extraordinary rainstorm, the water vapor from the southwest direction occupies an even larger proportion (74.3%). The annual total rainstorm precipitation in Tianjin city in 2012 was more than that in common years, and this is mainly due to the anomalous increase of water vapor from the southwest direction. This result further indicates that the annual total rainstorm precipitation in Tianjin is mainly influenced by the water vapor from the southwest direction. This study reveals that the majority of rainstorm in Tianjin originates from the western and southwestern directions, but significant heavy rainstorm events in Tianjin are particularly influenced by moisture from the southwestern direction. This research holds crucial implications not only for meteorological and water resource management in Tianjin but also provides valuable insights for global urban flood risk studies. [ABSTRACT FROM AUTHOR]

The current reverse-time migration, which is based on wave equations for imaging wavefields, employs an imaging formula derived from Claerbout's imaging principle. This imaging formula is only valid for plane waves with small incident angles on the perfectly flat reflecting surface. However, the complexity of seismic wave propagation may lead to situations that do not meet this requirement. Therefore, this paper divides the subsurface into local scattering and reflecting bodies. It proposes linear forward representations for scattering and reflection data based on perturbations in the physical parameters and wave impedance, respectively. To further describe the effect on the reflecting body boundary, the local reflection coefficient is defined and the linear forward representation for the reflection data based on it is obtained. After that, the proposed linear forward representations are used as the forward equations for the linear inverse of the seismic data, and the seismic data waveform imaging method is developed based on linear inversion theory. At the same time, the specific waveform imaging calculation formulas for scalar wave scattering data and scalar wave reflection data are provided and validated via numerical experiments. Compared with the current reverse-time migration, waveform migration not only has the correct phase and higher resolution in theory but also does not increase the computational complexity. To some extent, it improves the deficiencies of the current structural imaging and provides a basis for subsurface lithological imaging. [ABSTRACT FROM AUTHOR]

To predict the long-term skid resistance of steel slag asphalt mixtures, accelerated wear tests were conducted using an indoor accelerated loading device on the steel slag asphalt mixtures with different aggregate types, different steel slag blends, and different temperatures. The skid resistance decay law applied to the steel slag asphalt mixture under different influencing factors was investigated. Based on the skid resistance evaluation index measured during testing, a grey residual grey model (GM)(1,1)-Markov model was established to predict skid resistance. The results showed that the incorporation of steel slag significantly improves skid resistance while helping to reduce skid attenuation loss. Skid resistance increased with the increase in steel slag incorporation. With 100% steel slag incorporation, it was optimal. In addition, the test temperature did not change the decay law of the skid resistance index. With changes in temperature, skid resistance showed a decreasing trend. The prediction accuracy of the grey residual GM(1,1)-Markov model was significantly better than that of the grey GM(1,1) model and so can be used for skid resistance prediction. The results of the study can help to determine the attenuation characteristics of skid resistance of steel slag asphalt mixtures, and provide a simple and reliable method for predicting the skid resistance of these mixtures and other pavement aggregates. At the same time, it is certain guidelines for the establishment of the prediction model of asphalt mixture skid resistance under small sample conditions. [ABSTRACT FROM AUTHOR]