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Most magmatism occurring on Earth is conventionally attributed to passive mantle upwelling at mid-ocean ridges, to slab devolatilization at subduction zones, or to mantle plumes. However, the widespread Cenozoic intraplate volcanism in northeast China 1 – 3 and the young petit-spot volcanoes 4 – 7 offshore of the Japan Trench cannot readily be associated with any of these mechanisms. In addition, the mantle beneath these types of volcanism is characterized by zones of anomalously low seismic velocity above and below the transition zone 8 – 12 (a mantle level located at depths between 410 and 660 kilometres). A comprehensive interpretation of these phenomena is lacking. Here we show that most (or possibly all) of the intraplate and petit-spot volcanism and low-velocity zones around the Japanese subduction zone can be explained by the Cenozoic interaction of the subducting Pacific slab with a hydrous mantle transition zone. Numerical modelling indicates that 0.2 to 0.3 weight per cent of water dissolved in mantle minerals that are driven out from the transition zone in response to subduction and retreat of a tectonic plate is sufficient to reproduce the observations. This suggests that a critical amount of water may have accumulated in the transition zone around this subduction zone, as well as in others of the Tethyan tectonic belt 13 that are characterized by intraplate or petit-spot volcanism and low-velocity zones in the underlying mantle. The widespread intraplate volcanism in northeast China and the unusual ‘petit-spot’ volcanoes offshore Japan could have resulted from the interaction of the subducting Pacific slab with a hydrous mantle transition zone.

Miniaturized passive fliers based on smart materials face challenges in precise control of shape-morphing for aerodynamics and contactless modulation of diverse gliding modes. Here, we present the optical control of gliding performances in azobenzene-crosslinked liquid crystal networks films through photochemical actuation, enabling reversible and bistable shape-morphing. First, an actuator film is integrated with additive constructs to form a rotating glider, inspired by the natural maple samara, surpassing natural counterparts in reversibly optical tuning of terminal velocity, rotational rate, and circling position. We demonstrate optical modulation dispersion of landing points for the photo-responsive microfliers indoors and outdoors. Secondly, we show the scalability of polymer film geometry for miniature gliders with similar light tunability. Thirdly, we extend the material platform to other three gliding modes: Javan cucumber seed-like glider, parachute and artificial dandelion seed. The findings pave the way for distributed microflier with contactless flight dynamics control. Miniature passive fliers are of interest, but there are challenges in controlling their motion. Here, the authors report the use of light-responsive thin films for optical control of the gliding of passive fliers.

Carbonate sediments transported into the mantle at subduction zone settings account for the majority of the carbon flux into the Earth's interior and are thus critical to the deep carbon cycle. Understanding carbon storage volumes in the deep earth requires knowledge of the degree to which carbonate sediments are stored in the arc lithosphere or descend to the deep mantle. Here, we use petrological‐thermomechanical modeling to indicate that solid‐state diapirs dominate the removal of carbon from subducting plates, which may be the principal carbon‐release mechanism for the Cyclades (Greece) and Costa Rican forearcs. We find that forearc diapirs remove up to ∼80% of subducting carbon and develop diagonally upward, resulting in massive carbon storage in the subarc lithosphere. Outgassing from the carbon storage may cause high carbon outputs and explain volcanic gas with high δ13C at some subduction zones, affecting atmospheric CO2 concentration. Plain Language Summary Whereas many concepted models for the fate of subducting carbon, mainly from the sedimentary carbonates, have been proposed, it remains unclear to which extend these ideas are consistent with carbon balance between the shallow and deep reservoirs. The dynamic processes by which carbon release from subducting sediments and the transit into the shallow reservoirs above subarc depths remain largely unanswered. In this study, we account for metamorphic decarbonation and coupled with thermomechanical models, to investigate the dynamics of subducting sediments and associated carbon flux. Results show that solid‐state diapirs formed in the forearc remove substantial amounts of sedimentary carbon, which are much more than that via subarc diapirs and metamorphic reactions, and indicate that they dominate the carbon release from subducting sediments. The massive carbon stored in the overlying lithosphere reservoir is formed via the diagonal transport of forearc diapirs provided that a thick sediment, a young oceanic plate, and slow convergence are present. We argue that the remobilization of sedimentary carbon in the subarc lithosphere can provide an efficient mechanism for the abnormally high decarbonation efficiency of the volcanism in subduction zones, therefore regulating the Earth's climate. Key Points We conduct 2D petrological‐thermomechanical models to explore the sediment subduction and recycling in subduction zones Young oceanic plates, slow convergence rates, and thick sediments promote forearc diapirs and cause high decarbonation efficiency Forearc diapirs dominate removal of carbon from the subducting plate and reduce the proportion of the carbon released at subarc depths

The Iranian plateau is at the early stage of plateau development and intracontinental deformation in response to the Arabia‐Eurasia collision. Its compressive deformation is concentrated in the northern plateau but skips the central counterpart, challenging the common views envisaging the progressive uplift from the collisional front to the hinterland. Based on three‐dimensional, crustal‐scale numerical models, we present how the rheological heterogeneities common in continents control the deformation of the young Iranian plateau. The weak northern plateau ensures itself a preferential zone in accommodating continental collision. The N‐S strike‐slip faults within the non‐rigid central plateau, formed along the boundaries between the tectonic units with rheological contrast, suppress the shortening of the central plateau while further accentuating the compressive deformation of the northern plateau. Our results suggest a non‐progressive intracontinental deformation pattern where rheological boundaries and mechanically weak zones, not necessarily those close to collisional fronts, preferentially accommodate continental convergence. Plain Language Summary Continental collisions can produce extensive intracontinental deformation and uplift, forming orogenic plateaus. Common views predict progressive plateau uplift from the collisional front to the hinterland. In the young Iranian plateau, however, uplift mainly occurs in its northern and southern (collisional front) boundary zones while its central part shows relatively low elevation. Here, we perform numerical modeling experiments to investigate the deformation and uplift mechanisms of the Iranian plateau, which can promote our understanding of plateau evolution. The models show that only when the northern plateau is weaker than the central counterpart, uplift will preferentially occur in the north. The central plateau, which displays minor compressive deformation and uplift, is not necessarily rigid. The large‐scale N‐S strike‐slip faults in this region that developed along the boundaries between tectonic blocks with strength contrast can facilitate compressive deformation to concentrate on the northern plateau, making the central plateau less uplift. The results suggest that rheological boundaries and mechanically weak zones, not necessarily those close to collisional fronts, deform preferentially to accommodate continental convergence. Therefore, we suggest a non‐progressive intracontinental deformation pattern, since orogenic plateaus are usually composed of multiple tectonic blocks with different properties. Key Points 3D crustal‐scale models investigate the strain partitioning and non‐progressive uplift of the young Iranian plateau Rheological heterogeneities and large‐scale strike‐slip faults jointly dominate the intracontinental deformation Rheological boundaries and mechanically weak zones preferentially accommodate continental convergence

Spurred by the simultaneous need for data privacy protection and data sharing, federated learning (FL) has been proposed. However, it still poses a risk of privacy leakage in it. This paper, an improved Differential Privacy (DP) algorithm to protect the federated learning model. Additionally, the Fast Fourier Transform (FFT) is used in the computation of the privacy budget , to minimize the impact of limited arithmetic resources and numerous users on the effectiveness of training model. Moreover, instead of direct analyses of the privacy budget through various methods, Privacy Loss Distribution (PLD) and privacy curves are adopted, while the number of artificial assignments hyperparameters is reduced, and the grid parameters delineated for FFT use are improved. The improved algorithm tightens parameter bounds and minimizes human factors’ influence with minimal efficiency impact. It decreases the errors caused by truncation and discreteness of PLDs while expanding the discreteness interval to reduce the calculation workload. Furthermore, an improved activation function using a temper sigmoid with only one parameter , smooths the accuracy curve and mitigates drastically fluctuating scenarios during model training. Finally, simulation results on real datasets show that our improved DP algorithm, which accounts for long trailing, facilitates a better balance between privacy and utility in federated learning models.

The hot-phonon bottleneck effect in lead-halide perovskites (APbX 3 ) prolongs the cooling period of hot charge carriers, an effect that could be used in the next-generation photovoltaics devices. Using ultrafast optical characterization and first-principle calculations, four kinds of lead-halide perovskites (A=FA + /MA + /Cs + , X=I − /Br − ) are compared in this study to reveal the carrier-phonon dynamics within. Here we show a stronger phonon bottleneck effect in hybrid perovskites than in their inorganic counterparts. Compared with the caesium-based system, a 10 times slower carrier-phonon relaxation rate is observed in FAPbI 3 . The up-conversion of low-energy phonons is proposed to be responsible for the bottleneck effect. The presence of organic cations introduces overlapping phonon branches and facilitates the up-transition of low-energy modes. The blocking of phonon propagation associated with an ultralow thermal conductivity of the material also increases the overall up-conversion efficiency. This result also suggests a new and general method for achieving long-lived hot carriers in materials. Slow cooling of hot charge carriers in lead halide perovskite could be used in photovoltaics devices. Here, Yang et al . study hot carrier dynamics by transient absorption spectroscopy. They relate the phonon bottleneck to the up-conversion of low-energy phonons, facilitated by the presence of organic cations.

The distribution range, time-varying characteristics, and sources of lunar water are still controversial. Here we show the Chang’E-5 in-situ spectral observations of lunar water under Earth’s magnetosphere shielding and relatively high temperatures. Our results show the hydroxyl contents of lunar soils in Chang’E-5 landing site are with a mean value of 28.5 ppm, which is on the weak end of lunar hydration features. This is consistent with the predictions from remote sensing and ground-based telescopic data. Laboratory analysis of the Chang’E-5 returned samples also provide critical clues to the possible sources of these hydroxyl contents. Much less agglutinate glass contents suggest a weak contribution of solar wind implantation. Besides, the apatite present in the samples can provide hydroxyl contents in the range of 0 to 179 ± 13 ppm, which shows compelling evidence that, the hydroxyl-containing apatite may be an important source for the excess hydroxyl observed at this young mare region. Laboratory analysis of returned Chang’E-5 samples from the lunar surface show their hydroxyl contents to be on the weak end of lunar hydration features.

In this paper, we consider a low-latency Mobile Edge Computing (MEC) network where multiple User Equipment (UE) wirelessly reports to a decision-making edge server. At the same time, the transmissions are operated with Finite Blocklength (FBL) codes to achieve low-latency transmission. We introduce the task of Age upon Decision (AuD) aimed at the timeliness of tasks used for decision-making, which highlights the timeliness of the information at decision-making moments. For the case in which dynamic task generation and random fading channels are considered, we provide a task AuD minimization design by jointly selecting UE and allocating blocklength. In particular, to solve the task AuD minimization problem, we transform the optimization problem to a Markov Decision Process problem and propose an Error Probability-Controlled Action-Masked Proximal Policy Optimization (EMPPO) algorithm. Via simulation, we show that the proposed design achieves a lower AuD than baseline methods across various network conditions, especially in scenarios with significant channel Signal-to-Noise Ratio (SNR) differences and low average SNR, which shows the robustness of EMPPO and its potential for real-time applications.

Flying ad hoc networks (FANETs) have been gradually deployed in diverse application scenarios, ranging from civilian to military. However, the high-speed mobility of unmanned aerial vehicles (UAVs) and dynamically changing topology has led to critical challenges for the stability of communications in FANETs. To overcome the technical challenges, an Improved Weighted and Location-based Clustering (IWLC) scheme is proposed for FANET performance enhancement, under the constraints of network resources. Specifically, a location-based K-means++ clustering algorithm is first developed to set up the initial UAV clusters. Subsequently, a weighted summation-based cluster head selection algorithm is proposed. In the algorithm, the remaining energy ratio, adaptive node degree, relative mobility, and average distance are adopted as the selection criteria, considering the influence of different physical factors. Moreover, an efficient cluster maintenance algorithm is proposed to keep updating the UAV clusters. The simulation results indicate that the proposed IWLC scheme significantly enhances the performance of the packet delivery ratio, network lifetime, cluster head changing ratio, and energy consumption, compared to the benchmark clustering methods in the literature.

The influence of water content on mode I fracture toughness (K.sub.Ic) of mudstones has been studied using semi-circular bend (SCB) specimens subject to three-point bendings. And the mudstone SCB specimens are divided into three types, including Type-A, Type-B and Type-C, corresponding to the three configurations of the bedding planes, including divider direction, arrester direction, and transverse direction, respectively. The test results show that the values of K.sub.Ic for the three types of specimens are different due to the bedding structure, the Type-A specimens have the largest value of K.sub.Ic for the same soak period, while the Type-C specimens possess the smallest value. As the soak period increases, the K.sub.Ic of the three kinds of mudstone specimens decreases, and the fracture mechanisms of the specimens change gradually from the brittle failure form to the ductile failure form. Moreover, the standard deviation was used to quantify the anisotropy degree of the K.sub.Ic of the mudstone samples. As the water content increases, the standard deviation increases from 0.057 to 0.139, which indicates a significant increase in anisotropy of the K.sub.Ic of the mudstone specimens. In addition, the acoustic emission (AE) system was used to detect the AE events associated with the fracture initiation and propagation in the mudstone specimens for the different water content, with the raising water content, the cumulative AE events decrease, and the standard deviation of AE events increases, repesenting that the anisotropy of the AE events of the three types of specimens becomes more prominent. Further, the relationship between the tensile strength ([sigma].sub.t) and the K.sub.Ic of the three types of mudstone specimens for different water contents has been proved to be the linear relation.