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Monitoring sensors in complex engineering environments often record abnormal data, leading to significant positioning errors. To reduce the influence of abnormal arrival times, we introduce an innovative, outlier-robust localization method that integrates kernel density estimation (KDE) with damping linear correction to enhance the precision of microseismic/acoustic emission (MS/AE) source positioning. Our approach systematically addresses abnormal arrival times through a three-step process: initial location by 4-arrival combinations, elimination of outliers based on three-dimensional KDE, and refinement using a linear correction with an adaptive damping factor. We validate our method through lead-breaking experiments, demonstrating over a 23% improvement in positioning accuracy with a maximum error of 9.12 mm (relative error of 15.80%)—outperforming 4 existing methods. Simulations under various system errors, outlier scales, and ratios substantiate our method’s superior performance. Field blasting experiments also confirm the practical applicability, with an average positioning error of 11.71 m (relative error of 7.59%), compared to 23.56, 66.09, 16.95, and 28.52 m for other methods. This research is significant as it enhances the robustness of MS/AE source localization when confronted with data anomalies. It also provides a practical solution for real-world engineering and safety monitoring applications.

Abstract Fluids released from subducting slabs profoundly affect mantle composition, rock melting points, and arc magma generation. However, identifying fluid sources (sediments, crust, or mantle) and their ascent paths remains challenging. Magnesium isotopes are potential tracers for subduction-related fluids, though their behavior during hydrous peridotite dehydration remains unclear. Here we determined the equilibrium magnesium isotope fractionation factors between aqueous fluids and hydrous peridotitic minerals using first-principles calculations. Aqueous fluids prefer heavy magnesium isotopes relative to mantle silicate minerals, indicating that fluids released during hydrous peridotite dehydration are enriched in heavy magnesium isotopes relative to the residual minerals. Our simulations proposed that magnesium isotope variations in arc lavas from different subduction zones could be attributed to different dehydration reactions influenced by subduction zone thermal structures. This study highlights the potential of magnesium isotopes for tracing fluids originating from subducting hydrated mantle, providing insights into the thermal structure of various subduction zones.

Abstract The relative roles of protoplanetary differentiation versus late accretion in establishing Earth’s life-essential volatile element inventory are being hotly debated. To address this issue, we employ first-principles calculations to investigate nitrogen (N) isotope fractionation during Earth’s accretion and differentiation. We find that segregation of an iron core would enrich heavy N isotopes in the residual silicate, while evaporation within a H2-dominated nebular gas produces an enrichment of light N isotope in the planetesimals. The combined effect of early planetesimal evaporation followed by core formation enriches the bulk silicate Earth in light N isotopes. If Earth is comprised primarily of enstatite-chondrite-like material, as indicated by other isotope systems, then late accretion of carbonaceous-chondrite-like material must contribute ~ 30–100% of the N budget in present-day bulk silicate Earth. However, mass balance using N isotope constraints shows that the late veneer contributes only a limited amount of other volatile elements (e.g., H, S, and C) to Earth.

Acoustic emission (AE) localization algorithms based on homogeneous media or single-velocity are less accurate when applied to the triaxial localization experiments. To the end, a robust triaxial localization method of AE source using refraction path is proposed. Firstly, the control equation of the refraction path is established according to the sensor coordinates and arrival times. Secondly, considering the influence of time-difference-of-arrival (TDOA) errors, the residual of the governing equation is calculated to estimate the equation weight. Thirdly, the refraction points in different directions are solved using Snell’s law and orthogonal constraints. Finally, the source coordinates are iteratively solved by weighted correction terms. The feasibility and accuracy of the proposed method are verified by pencil-lead breaking experiments. The simulation results show that the new method is almost unaffected by the refraction ratio, and always holds more stable and accurate positioning performance than the traditional method under different ratios and scales of TDOA outliers.

Abstract The primary methods of assessing the reliability of distribution networks comprise analytic and simulation methods. However, both approaches require the identification and computation of network topology, which precludes their expression in explicit, continuous functions, consequently impeding the incorporation of reliability constraints into planning and operational optimization models. To tackle this restriction, the present work puts forth a novel linear‐programming‐based reliability assessment method that is mathematically formulated, considering distribution automation (DA) and distributed generations (DGs), consisting of both conventional and renewable energy sources. In this paper, the clustering method and the scenario‐based method are used to model DGs. Next, a mixed integer linear programming (MILP) model, considering the DA and DGs with the System Average Interruption Duration Index (SAIDI) as the optimization objective, is proposed. Finally, the feasibility and effectiveness of the proposed method are verified in a 37‐node distribution network system.

Space bearing retainers are widely made of a porous, oil-impregnated material due to the unmaintainability of spacecraft. Porous polyimide (PI) material with a certain micropore structure can be used as a lubricant storage and migration channel to realize the lubricant circulation supply in the bearing system. In this work, molecular dynamics simulations are adopted to model the lubricant outflow process from the pore of the PI material. Coarse-grained models are constructed to investigate the lubricant migration behaviors with different rotation speeds, rotation radii, and pore sizes. The results show that a lubricant within the pore fails to outflow due to the capillary effect in a static state. However, for the rotating pores, if the centrifugal forces resulting from rotation exceed the capillary forces, the lubricants will begin to flow out. Furthermore, the lubricant in the large pore is easier to outflow due to the smaller capillary force, which is the main mechanism of lubricant outflow from the pores.

Abstract Inspired by the dynamic wet adhesive systems in nature, various artificial adhesive surfaces have been developed but still face different challenges. Crucially, the theoretical mechanics of wet adhesives has never been sufficiently revealed. Here, we develop a novel adhesive mechanism for governing wet adhesion and investigate the biological models of honeybee arolium for reproducing the natural wet adhesive systems. Micro-nano structures of honeybee arolium and arolium-prints were observed by Cryogenic scanning electron microscopy (Cryo-SEM), and the air pockets were found in the contact interface notably. Subsequently, the adhesive models with a three-phase composite interface (including air pockets, liquid secretion, and hexagonal frames of arolium), were formed to analyze the wet adhesion of honeybee arolium. The results of theoretical calculations and experiments indicated an enhanced adhesive mechanism of the honeybee by liquid self-sucking effects and air-embolism effects. Under these effects, normal and shear adhesion can be adjusted by controlling the proportion of liquid secretion and air pockets in the contact zone. Notably, the air-embolism effects contribute to the optimal coupling of smaller normal adhesion with greater shear adhesion, which is beneficial for the high stride frequency of honeybees. These works can provide a fresh perspective on the development of bio-inspired wet adhesive surfaces.

Abstract Three-dimensional (3D) frictional contact model of functionally graded magneto-electro-elastic (FGMEE) material with a conducting spherical punch under electromagnetic fields is presented. Two types of imperfect bonding interface of layers, dislocation-like interface and force-like interface, are considered. Frequency response functions (FRFs) for multilayered MEE material with imperfect interface subjected to unit mechanical, electric, and magnetic loads are derived. The FRFs are used with the semi-analytical method (SAM) to solve present multiphysical contact problem. The present model is verified by comparing with literatures and the finite element method (FEM) and used to study the contact problem of FGMEE film imperfectly bonded on homogenous MEE half-space under electromagnetic fields. Parametric studies are conducted to reveal the effects of imperfect interfaces and also film properties including gradient index and thickness.

Abstract The fine-scale seismic features near the inner core boundary (ICB) provide critical insights into the thermal, chemical, and geodynamical interactions between liquid and solid cores, and may shed light on the evolution mechanism of the Earth’s core. Here, we utilize a dataset of pre-critical PKiKP waveforms to constrain the fine structure at the ICB, considering the influence of various factors such as source complexity, structural anomalies in the mantle, and properties at the ICB. Our modeling suggests a sharp ICB beneath Mongolia and most of Northeast Asia, but a locally laminated ICB structure beneath Central Asia, Siberia, and part of Northeast Asia. The complex ICB structure might be explained by either the existence of a kilometer-scale thickness of mushy zone, or the localized coexistence of bcc and hcp iron phase at the ICB. We infer that there may be considerable lateral variations in the dendrites growing process at ICB, probably due to the complicated thermochemical and geodynamical interaction between the outer and inner core.

Abstract Polytetrafluoroethylene (PTFE) has been widely used as a lubrication additive for reducing friction and wear; however, the hydrophobic nature of PTFE restricts its application in eco-friendly water-based lubrication systems. In this study, for the first time, we designed novel PTFE@silica Janus nanoparticles (JNs) to meet the requirement for additives in water-based lubricants, which have excellent dispersion stability in water attributed to the unique amphiphilic structure. By introducing the lubrication of the aqueous dispersion of the JNs with a concentration of 0.5 wt%, the coefficient of friction (COF) and wear volume were reduced by 63.8% and 94.2%, respectively, comparing to those with the lubrication of pure water. Meanwhile, the JNs suspension also exhibits better lubrication and wear-resistance performances comparing to commercial silica and PTFE suspensions. The excellent tribological behaviors of PTFE@silica JNs as nano-additives could be attributed to the synergetic effect of the two components, where the PTFE provided lubrication through the formed tribofilms on the friction pairs, and the rigid silica further enhanced the wear-resistance performance. Most importantly, the unique structure of JNs makes it possible to use PTFE as an additive in water-lubrication systems. Our study shed light on the design and application of novel JNs nanomaterials as additives to meet the requirements of future industrial applications.

Efficient and stable heat dissipation structure is crucial for improving the convective heat transfer performance of thermal protection systems (TPSs) for hypersonic aircraft. However, the heat dissipation wall of the current TPS is limited by a single material and structure, inefficiently dissipating the large amount of accumulated heat generated during the high-speed maneuvering flight of hypersonic aircraft. Here, a convection cooling channel structure of TPS is proposed, which is an innovative multi-level structure inspired by the natural honeycomb. An active cooling channel (PCM-HC) is designed by using a variable-density topology optimization method and filled with phase change material (PCM). Numerical simulations are used to investigate the thermal performance of the PCM-HC wall, focusing on the influence of PCM properties, structural geometric parameters, and PCM types on heat transfer characteristics. The results demonstrate that the honeycomb-like convection cooling channel wall, combined with PCM latent heat of phase change, exhibits superior heat dissipation capability. With a heat flux input of 50 kW/m2, the maximum temperature on the inner wall of PCM-HC is reduced by 12 K to 20 K. Different PCMs have opposing effects on heat transfer performance due to their distinct thermophysical properties. This work can provide a theoretical basis for the design of high-efficiency cooling channel, improving the heat dissipation performance in the TPS of hypersonic aircraft.

The lubrication performance of bearings is greatly influenced by the distribution of the lubricant. In this study, a cylindrical rolling bearing test rig was constructed and presented. The distribution of grease and lubricating oil along the contact region was examined using the laser-induced fluorescence technique, and the thickness of the layer was determined. The lubricating oil and grease layer thickness distribution map was acquired. The effects of supply amount, thickener content, and speed on grease distribution were examined. Mechanisms for replenishing the line contact area were investigated.

Abstract Anhydrous phase B (anh‐B) is a dense magnesium silicate with the composition Mg14Si5O24 and space group Pmcb. In magnesium‐rich environments, forsterite reacts with periclase to form anh‐B, and the formation of anh‐B was proposed as a plausible mechanism for the origin of the X‐discontinuity. However, the elastic properties of anh‐B, which are critical for evaluating the seismic features associated with its formation, have not been determined. In this study, we investigated the elasticity of anh‐B at high pressure and temperature via first‐principles calculations. Combining with the elasticity of other minerals, we determined the contrasts caused by the formation of anh‐B: ∼3%, ∼7%, and ∼10% jumps for density, VP, and VS, respectively. The 2%–8% impedance contrasts of the X‐discontinuity can be explained by the formation of 15–60 vol% anh‐B, which requires 3–12 vol% MgO as a reactant.

Abstract Superlubricity has drawn substantial attention worldwide while the energy crisis is challenging human beings. Hence, numerous endeavors are bestowed to design materials for superlubricity achievement at multiple scales. Developments in graphene-family materials, such as graphene, graphene oxide, and graphene quantum dots, initiated an epoch for atomically thin solid lubricants. Nevertheless, superlubricity achieved with graphene-family materials still needs fundamental understanding for being applied in engineering in the future. In this review, the fundamental mechanisms for superlubricity that are achieved with graphene-family materials are outlined in detail, and the problems concerning graphene superlubricity and future progress in superlubricity are proposed. This review concludes the fundamental mechanisms for graphene superlubricity and offers guidance for utilizing graphene-family materials in superlubricity systems.

Abstract An oil-impregnated porous polyimide (PI) retainer is used in space rolling bearings to improve the lubrication performance, which depends on the release of lubricant from the pores, and therefore is closely related to the pore size. To study the effect of pore size, in this work, PI materials with different pore sizes were prepared by preheating the retainer tube billet during the limit pressing process, and then the friction tests were conducted with the ball-on-ring mode. The results show that the applied load deforms the pores, allowing the lubricant to be squeezed out from the pore; the centrifugal effect induced by rotation also makes the lubricant migrate out of the pore. Therefore, for the same pore sizes, the friction coefficients decrease with the increasing loads and rotation speeds. In addition, it was found that there exists an optimal pore size for the best lubrication properties of porous PI material. Furthermore, the optimal pore size should be larger for lubricants with high viscosity. The microscopic mechanism for lubricant outflow from pores is clarified by molecular dynamic simulations. The insights gained in this study can guide the preparation of oil-impregnated porous retainers under different working conditions.

Abstract Protecting and restoring the degraded arid lakes are globally urgent issues. We document a potential recovery of the dried salt-lake, Lop Nur called "the Sea of Death" which is located at the terminus of the largest inland basin in China, the Tarim River Basin. The changes and relationship of surface water with climate parameters and groundwater in the basin over the last 30 years are analyzed, by using satellite remote sensing and land data assimilation products. We find that with increased surface water in the basin, the groundwater level in Lop Nur began to show an obvious positive response in 2015; and the rate of decline of the groundwater level is slowing down. We argue that after a balance is achieved between regional groundwater recharge and evapotranspiration, the Lop Nur ecosystem will gradually recover. This study shows an encouraging case for the protection and restoration of degraded lakes in dryland regions around the world.

Abstract Around 1,000 peer-reviewed papers were selected from 3,450 articles published during 2020–2021, and reviewed as the representative advances in tribology research worldwide. The survey highlights the development in lubrication, wear and surface engineering, biotribology, high temperature tribology, and computational tribology, providing a show window of the achievements of recent fundamental and application researches in the field of tribology.

The dynamic adhesive systems in nature have served as inspirations for the development of intelligent adhesive surfaces. However, the mechanisms underlying the rapid controllable contact adhesion observed in biological systems have never been adequately explained. Here, the control principle for the unfolding adhesive footpads (alterable contact area) of honeybees is investigated. The footpads can passively unfold, even without neuro-muscular reflexes, in response to specific dragging activity (generating shear force) toward their bodies. This passive unfolding is attributed to the structural features of the soft footpads, which cooperate closely with shear force. Then, the hierarchical structures supported by numerous branching fibers were observed and analyzed. Experimental and theoretical findings demonstrated that shear force can decrease fibril angles with respect to the shear direction, which consequently induces the rotation of the interim contact area of the footpads and achieves their passive unfolding. Furthermore, the decrease in fibril angles can lead to an increase in the liquid pressure within the footpads, and subsequently enhance their unfolding. This study presents a novel approach for passively controlling the contact areas in adhesive systems, which can be applied to develop various bioinspired switchable adhesive surfaces.

The pyrolite model, which can reproduce the upper-mantle seismic velocity and density profiles, was suggested to have significantly lower velocities and density than seismic models in the lower mantle transition zone (MTZ). This argument has been taken as mineral-physics evidence for a compositionally distinct lower MTZ. However, previous studies only estimated the pyrolite velocities and density along a one-dimension (1D) geotherm and never considered the effect of lateral temperature heterogeneity. Because the majorite-perovskite-akimotoite triple point is close to the normal mantle geotherm in the lower MTZ, the lateral low-temperature anomaly can result in the presence of a significant fraction of akimotoite in pyrolitic lower MTZ. In this study, we reported the elastic properties of Fe-bearing akimotoite based on first-principles calculations. Combining with literature data, we found that the seismic velocities and density of the pyrolite model can match well those in the lower MTZ when the lateral temperature heterogeneity is modeled by a Gaussian distribution with a standard deviation of ∼100 K and an average temperature of dozens of K higher than the triple point of MgSiO3. We suggest that a harzburgite-rich lower MTZ is not required and the whole mantle convection is expected to be more favorable globally.

Abstract Background This study analyzed the efficacy and safety of neoadjuvant chemotherapy with liposomal paclitaxel plus platinum in patients with locally advanced resectable esophageal squamous cell carcinoma (ESCC). Methods The data of patients with locally advanced resectable ESCC (staging cT2N + M0, cT3‐4aNanyM0, IA‐IVA) who received preoperative chemotherapy with liposomal paclitaxel plus platinum (cisplatin, nedaplatin or carboplatin) in HuanXing Cancer Hospital from July 2018 to October 2019 were collected. The primary endpoint of this study was R0 resection rate, and secondary endpoints were pathological complete response (pCR) rate, 1‐ and 2‐year overall survival (OS) rate, 1‐year and 18‐month disease‐free survival (DFS) rate, and safety. Results A total of 32 eligible patients were included in this study. All patients received neoadjuvant chemotherapy and surgery. The R0 resection rate was 93.8%, the pCR rate was 12.5%, and down‐staging was achieved in 14 patients (47.8%). Median follow‐up was 31.0 months (95% confidence interval [CI] 30.1–31.9 months). The 1‐ and 2‐year OS rates were 96.9% and 78.1%, and the 1‐year and 18‐month DFS rates were 86.7% and 76.7%, respectively. The median DFS and OS were not reached. The incidence rate of neoadjuvant chemotherapy related grade 3–4 adverse events was 21.9%, including neutropenia (21.9%) and leukopenia (9.4%). Conclusions The results of this study suggest that liposomal paclitaxel combined with platinum as neoadjuvant chemotherapy can provide satisfactory R0 resection rate and survival rate, and significant tumor down‐staging effect for patients with locally advanced resectable ESCC, with safety profile.

Biomachine hybrid robots have been proposed for important scenarios, such as wilderness rescue, ecological monitoring, and hazardous area surveying. The energy supply unit used to power the control backpack carried by these robots determines their future development and practical application. Current energy supply devices for control backpacks are mainly chemical batteries. To achieve self-powered devices, researchers have developed solar energy, bioenergy, biothermal energy, and biovibration energy harvesters. This review provides an overview of research in the development of chemical batteries and self-powered devices for biomachine hybrid robots. Various batteries for different biocarriers and the entry points for the design of self-powered devices are outlined in detail. Finally, an overview of the future challenges and possible directions for the development of energy supply devices used to biomachine hybrid robots is provided.

IntroductionCalcium sensor calcineurin B-like proteins (CBLs) and their interacting partners, CBL-interacting protein kinases (CIPKs), have emerged as a complex network in response to abiotic and biotic stress perception. However, little is known about how CBL-CIPK complexes function in potatoes.MethodsIn this study, we identified the components of one potato signaling complex, StCBL4–StCIPK2, and characterized its function in defense against Rhizoctonia solani causing stem canker in potato.ResultsExpressions of both StCBL4 and StCIPK2 from potato were coordinately induced upon R. solani infection and following exposure to the defense genes. Furthermore, transient overexpression of StCBL4 and StCIPK2 individually and synergistically increased the tolerance of potato plants to R. solani in Nicotiana benthamiana. Additionally, the transgenic potato has also been shown to enhance resistance significantly. In contrast, susceptibility to R. solani was exhibited in N. benthamiana following virus-induced gene silencing of NbCBL and NbCIPK2. Evidence revealed that StCBL4 could interact in yeast and in planta with StCIPK2. StCBL4 and StCIPK2 transcription was induced upon R. solani infection and this expression in response to the pathogen was enhanced in StCBL4- and StCIPK2-transgenic potato. Moreover, accumulated expression of pathogenesis-related (PR) genes and reactive oxygen species (ROS) was significantly upregulated and enhanced in both StCBL4- and StCIPK2- transgenic potato.DiscussionAccordingly, StCBL4 and StCIPK2 were involved in regulating the immune response to defend the potato plant against R. solani. Together, our data demonstrate that StCBL4 functions in concert with StCIPK2, as positive regulators of immunity, contributing to combating stem canker disease in potato.

Rivers are the main supply sources in inland areas for human activities, but they are also regarded as the most susceptible water bodies to pollutants. Understanding the key factors influencing the chemical characteristic is the basis for water supply and public health concern. And it is helpful for the protection of surface water under the influence of human activities. To reveal the hydrochemical process of river water and the key factors affecting the chemical compositions, a total of 33 samples from rivers in Muling-Xingkai Plain are collected for principal component analysis and hydrochemical analysis. Results indicate that river water is characterized by the type of HCO3-Ca and mixed HCO3-Ca·Na. But some samples with relative high nitrate content have Cl− as the dominant anion. The natural sources of chemical ions in river water are silicate and carbonate minerals. The chemical fertilizers only slightly influence the chemical compositions of river water due to the retardation of black soil with weak permeability. The chemical compositions of river water in Muling river are significantly influenced by domestic sewage compared with that in Abuqin river and Qihulin river. The widespread thick black soils play a key roles in protecting the river quality and groundwater quality, and human activities only play a limited roles in determining the river quality in the Muling-Xingkai Plain. At present, the contents of major chemical ions in river water meet the irrigation standard. Although the irrigation with river water do not lead to the food safety issue, the government agencies should adopt adequate measures to control the indiscriminate discharge of domestic sewage and application of fertilizers for preventing the accumulation of pollutants in rivers. This study is beneficial to the efficient management of surface water resources in agricultural areas with similar geological conditions and hydrogeological conditions.

The Jiangcang Basin is a Cenozoic faulted basin, where many low-temperature warm springs are exposed, with the highest temperature being 36.6°C. The study of the hydrogeochemical characteristics of the geothermal fluids of these warm springs can effectively clarify the genetic mechanisms of the geothermal resources in the Jiangcang Basin and thus is of great significance for the development and utilization of geothermal resources in the Qinghai Province. Using the geothermal and geological conditions of the Jiangcang Basin, this study analyzed the hydrochemical and isotopic characteristics of water samples collected from cold water and from four warm springs in the Jiangcang Basin, obtaining the following results. The four warm springs have the hydrochemical types of HCO3-Ca·Mg, HCO3-Ca·Na·Mg, and HCO3·SO4-Na·Ca and total dissolved solids (TDSs) of 720.4–1,663 mg/L. Moreover, no significant positive correlation is found between Cl− and other ions in the warm springs. The results of isotopic analysis show that the warm springs are mainly recharged by atmospheric precipitation and meltwater from ice and snow, with a recharge elevation of 4,401–4,501 m. Furthermore, the geothermal reservoirs in the Jiangcang Basin have temperatures of 51–83°C and circulation depths of 1,848–2,610 m. Atmospheric precipitation and the meltwater from ice and snow infiltrate downward in high mountain areas and form runoffs along the tectonic channels in the basin. After being heated through deep circulation, they migrate upward along fault fracture zones under the influence of faults and the water blocking of mudstones, during which they cool by thermal conduction and mixing with shallow cold groundwater. Finally, the mixed water is exposed in the form of low-temperature tectonic warm springs. The results of this study can provide data for the exploitation and utilization of geothermal resources in the Qinghai Province.

Laryngeal carcinoma is the most common head and neck malignancy globally, and chemotherapy is still the most common treatment for this type of carcinoma. Monotherapy has become powerless because of the lack of drugs in the anticancer agent library, the difficult process of new drug discovery, and the widespread drug resistance. Combination therapy with two agents, in particular Chinese herbal medicines with chemotherapy drugs, is a potential alternative to chemotherapy alone. However, combination therapy faces difficulties in delivering multiple drugs to tumor tissue in a precise ratio. Here, a cocktail polymeric prodrug micelle (PHPPM) was developed using an oxidation and reduction dual-responsive polymeric paclitaxel (PTX) and polymeric honokiol (HK) prodrugs. Both of them were obtained by covalently conjugating the drug to dextran via diselenium bonds. Following optimization and characterization, the PHPPM with the precise mass ratio of PTX and HK was obtained, enabling ratiometric drug loading, synchronized drug release in response to tumor high-level reactive oxygen species and glutathione environment, long blood circulation, and high tumor accumulation. This co-delivery system can effectively inhibit laryngeal carcinoma growth in vitro and in vivo. Codelivery of chemotherapy agents and Chinese herbal medicine with a precise ratio and controlled release of the two drugs at the tumor site provides an effective approach to clinical therapy for other laryngeal carcinomas.

Dense Fe3+-rich bridgmanite can explain the seismic features of Large Low Shear Velocity Provinces, as it can form large-scale thermochemical piles in the deep mantle that remain stable throughout Earth’s history.

Based on Nickel isotope analysis of meteorites and terrestrial rocks, the authors suggest that the Bulk Silicate Earth has a sub-chondritic Nickel isotope composition. This signature is thought to result from the impact and accretion of a Mercury-like impactor which originated from the innermost Solar System.

Seismology is a powerful tool to investigate Earth’s interior. Here, the authors combine numerical approaches with experimental results from previous studies to show a depth dependent behaviour of seismic waves in subducted oceanic crust in Earth’s mantle. The work challenges the currently accepted model of depth-independent seismic wave behaviour in oceanic crust.

The artificial locomotion control strategy is the fundamental technique to ensure the accomplishment of the preset assignments for cyborg insects. The existing research has recognized that the electrical stimulation applied to the optic lobes was an appropriate flight control strategy for small insects represented by honeybee. This control technique has been confirmed to be effective for honeybee flight initiation and cessation. However, its regulation effect on steering locomotion has not been fully verified. Here, we investigated the steering control effect of honeybee by applying electrical stimulation signals with different duty cycles and frequencies on the unilateral optic lobes and screened the stimulus parameters with the highest response successful rate. Moreover, we confirmed the effectiveness of steering control by verifying the presence of rotation torque on tethered honeybees and the body orientation change of crawling honeybees. Our study will contribute some reliable parameter references to the motion control of cyborg honeybees.

When oil droplets impact a solid surface for oil-air lubrication, they may spread out to produce a thin oil layer on the surface, which serves as a significant source of lubrication. A test rig was constructed in this research to observe the spreading behavior of oil droplets impacting surfaces from both frontal and lateral views. From the frontal view, laser-induced fluorescence techniques are used to measure the thickness of the oil layer quantitatively during the spreading of oil droplets. While the lateral view can observe the shape evolution of the droplets. Oil droplet spreading patterns on the sheet with dry surfaces and with different thin liquid film thicknesses were studied, and the effect of viscosity and the thickness of the thin liquid film on spreading radius and spreading thickness is considered. The experimental findings demonstrate that the maximum spreading factor, the spreading central layer thickness, and the apparentness of retraction all increase as viscosity increases. The retraction is obviously impacted by thin liquid films, and the retraction weakens as the thin liquid film thickness increases.

In this study, silicon isotope fractionation factors for metamorphic silicate including muscovite, epidote, and kyanite are calculated using first-principles methods based on density-functional theory. The reduced partition function ratio (103lnβ) of 30Si/28Si decreases in the order of muscovite > epidote ≈ kyanite. Combining with previous calculations, our results show that the equilibrium silicon isotope fractionation factors are correlated with average Si–O bond length. These results predict that measurable Si isotope fractionation can occur during metamorphic fluid activities. At 1000 K, the calculated 103lnα values for quartz–epidote, quartz–kyanite, and quartz–muscovite are 0.51‰, 0.49‰, and 0.08‰, respectively. The calculation results are generally consistent with the observed Si isotopic data in two metamorphic eclogite-vein systems, showing that our work can provide useful information in investigating the Si isotope fractionation in metamorphic fluid evolution. Keywords: Si isotopes, First-principles calculation, Metamorphic fluid

While methane is a simple, abundant feedstock for chemical industry, the selective and facile conversion to more-complex products is challenging. Here, authors show copper-containing polymeric carbon nitride to convert methane to ethanol using light under mild conditions.

Graphene-family materials have been investigated by researchers as promising additives for various lubrication systems due to their unique physical-chemical properties. It has been proven that graphene-family materials can lead to enhanced lubrication and wear-resistance performance, which have potential to reduce the energy losses and carbon emissions, and the wear of machines for industrial applications. Experimental, theoretical, and simulation studies have been performed to investigate the tribological behaviors of graphene-family materials as additives. The tribological properties of graphene-family materials, including graphene, reduced graphene oxide, functionalized graphene, and the combination of graphene-family materials and other materials as additives, and the fundamental mechanism are systematically reviewed and concluded. The authors also discuss the potential engineering applications of graphene-family materials as lubricating additives, and the unsolved issues and optimistic outlooks in the near future.

Diamonds form in a variety of environments between subducted crust, lithospheric and deep mantle. Recently, deep source diamonds with inclusions of the high-pressure H2O-phase ice-VII were discovered. By correlating the pressures of ice-VII inclusions with those of other high-pressure inclusions, we assess quantitatively the pressures and temperatures of their entrapment. We show that the ice-VII-bearing diamonds formed at depths down to 800 ± 60 km but at temperatures 200–500 K below average mantle temperature that match the pressure-temperature conditions of decomposing dense hydrous mantle silicates. Our work presents strong evidence for coupled recycling of water and carbon in the deep mantle based on natural samples.

This work studied the lubrication performances of polyalkylene glycols, which are insulating oils, at the steel interface under external electric fields. The results show that external electric fields greatly affect the lubrication performances of polyalkylene glycols, and there is an optimal voltage (−1.0 V) for the improvement in friction reduction performance. The surface analysis and experiment results indicate that the polyalkylene glycol adsorption film and the reduction in the amount of FexOy and FeOOH in the tribochemical film contribute to improved friction performance under the negative voltage condition. This work proves that the lubrication performances of insulating oils can be affected by external electric fields as well. A lubrication model was proposed, hoping to provide a basic understanding of the lubrication mechanisms of ether-bond-containing insulating oils in the electric environment.

Friction and wear usually lead to huge energy loss and failure of machine pairs, which usually causes great economic losses. Researchers have made great efforts to reduce energy dissipation and enhance durability through advanced lubrication technologies. Single-layer coatings have been applied in many sectors of engineering, but the performance of single-layer coatings still has many limitations. One solution to overcome these limitations is to use a multilayer coating that combines different components with varied physical and chemical properties. In addition, multilayer coating with alternating layers only containing two components can lead to improved performance compared to a coating with only two different layers. This paper systematically reviews the design concept and properties of different types of multilayer coatings, including transition-metal nitride coatings, diamond-like carbon-based coatings, and other multilayer coatings. The inherent functional mechanisms of the multilayer structures are also detailed and discussed.

In order to reduce the misoperation of submersible pilots in the complex environment of deep sea and improve human reliability, it is a very important method to optimize the cabin space of manned submersible. In this paper, manned submersible Jiaolong is taken as an example to describe the breakthrough of traditional modes for optimizing the cabin layout of manned submersible with an aesthetic perspective of deconstruction and reconstruction thinking; the layout is optimized based on deconstruction and reconstruction from the cultural perspective of interdisciplinary. The experimental results show that the layout of manned submersible cabin is optimized by combining the theory of deconstruction and reconstruction aesthetics and human factors engineering, and the feasibility and effectiveness of this method are verified by multiobjective genetic algorithm. Deconstruction and reconfiguration layout optimization improves the human reliability of divers. It is a new method for the optimization of manned submersible cabin layout and also provides a reference for studies on the layout of similar small space.

Superlubricity can be unstable in graphene systems, especially under high applied loads. Here the authors use microspheres uniformly coated by graphene to measure friction between 2D materials and show that superlow friction is preserved for long periods of time under high loads and various atmospheres.

Stimuli‐responsive materials change their physical or chemical properties in response to external stimuli just like they have thoughts, which plays an important role in developing intelligent living systems for human beings. Thereto, recently developed soft photo‐actuators based on functional polymers demonstrate their capabilities of performing diverse mechanical movements, such as walking, swimming, and gripping, under the control of the light stimulus. Different from conventional electric power‐driven robots, soft photo‐actuators can complete the procedures of sensing light signals and converting them into mechanical work simultaneously without complex serial‐parallel circuits. They are promising candidates for soft robotics due to their advantages in miniaturization, controllability, and functionality. Herein, the progress of soft photo‐actuators regarding their materials structure and working mechanisms and the design strategy for a robust and intelligent system are elucidated. In addition, the significance of introducing self‐feedback loops to the actuator in realizing automatic and continuous motion is also emphasized. In future, soft photo‐actuators will be utilized in biomimetic or medical systems if their intelligent performances are further improved.

Breastfeeding has a wide range of benefits for both infants and mothers. The identification of factors associated with exclusive breastfeeding (EBF) are important to increase the prevalence of EBF. The study aimed to determine the prevalence of EBF within the first six months and its associated factors in Kaiyuan, Yunnan Province, Southwest China. This cross-sectional study was conducted in Kaiyuan, a middle-sized city of Yunnan Province, Southwest China. Mothers of infants under twelve months were randomly selected for a face to face interview in four towns (two in urban areas and two in rural areas) in Kaiyuan. A structured questionnaire was applied for collection of sociodemographic information, mothers' and infants' health, and breastfeeding information. A 24-hour food recall survey was used to collect infant feeding information. A logistic regression analysis was performed to identify the factors independently associated with exclusive breastfeeding for infants up to six months of age. The number of 417 mothers with infants under six months was interviewed. The prevalence of EBF at six months was 27.34%. Logistic regression indicated that EBF within six months was more likely to be practiced by mothers who had higher average household income per year (OR = 2.09, 95% CI: 1.05-4.17 p = 0.037; OR = 1.85, 95% CI: 1.04-3.28 p = 0.037), and mothers who received breastfeeding information (OR = 2.46, (95%CI: 1.45-4.18, p = 0.0009). The prevalence of EBF in Kaiyuan, Southwest China is considerably lower than national and international recommendations. Yearly household income, and mothers who received breastfeeding information are associated with higher EBF prevalence. Breastfeeding information should be given to mothers in order to increase the prevalence of EBF.

Abstract There are few experimental results available on film thickness at speeds above 5 m/s and they are almost all based on the optical ball-on-disc test rig. In contrast to the contacts in a rolling bearing, in which the lubricant in the oil reservoir distributes symmetrically, ball-on-disc contact shows asymmetry of lubricant distribution due to centrifugal effects. In order to closely imitate the contact occurring between the ball and the outer ring of a ball bearing, this study proposes an experimental model based on ball-on-glass ring contact. An optical matrix method is used to analyze the optical system, which is composed of a steel ball-lubricant-chromium-coated glass ring. Based on the optical analysis, the measurement system is improved in order to obtain a high quality interference image, which makes it possible to measure the film thickness at high-speeds conditions.

Abstract Oil–air lubrication supplies lubricants in the form of droplets to elastohydrodynamic lubrication (EHL) contacts, such as those in high-speed spindle bearings. However, there is a paucity of information related to understanding the lubrication behaviors of oil droplets within EHL contacts. In this study, behaviors of lubricant droplets, in terms of spreading around a static contact as well as passing through a rolling contact, were studied with an optical ball-on-disk EHL test rig. Influences of oil droplet size, viscosity, and surface tension on droplet spreading were examined. Lubricating film formation was also investigated when droplets traveled through the EHL contact region. The results indicated that droplet size and running speed significantly influenced film profiles. With increasing entrainment speeds, a small droplet passed through the contact without spreading and generated films with a significant depression in the central contact region.

This study aimed to investigate the impact of a horse hoof wall on three solid surfaces: steel, concrete and asphalt. Impact experiments were conducted for different impact angles and different initial impact velocities. The effect of impact surfaces, impact angles and initial impact velocities on the coefficient of restitution and the effective coefficient of friction were tested using one-way ANOVA. Analytical and numerical modeling of the impact were developed. The impact interval was divided into two phases: compression and restitution. For compression, a contact force with a damping term was used. The restitution was characterized by an elastic contact force. The stiffness and damping coefficients of the contact force were estimated from the normal impacts. The simulated velocities after the oblique impacts were compared to the velocities in the in vitro investigation. The coefficient of restitution varied significantly on different surfaces. The effective coefficient of friction was lower on steel compared to concrete and asphalt. The model presented in this study can be applied to refine the impact simulation of the equine hoof during locomotion.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Porous copper matrix composites (PCMCs) as a novel potential sliding electrical contact material has superior self-lubricating properties, which could store lubricant and during working release it under external stimuli (frictional force, electricity, etc.) to improve the tribological performance. However, the porous structure of the composites may lead to the decrease of its mechanical strength. The method to synthesize PCMCs with enhanced mechanical properties, high electrical conductivity, and novel self-lubricating properties is explored. In this study, gradient porous copper-zinc composites (GPCMCs) are fabricated with novel self-lubricating properties and enhanced strength. The basic physical and mechanical properties of PCMCs and GPCMCs with different porosities are investigated firstly and their frictional behaviors with or without stored ionic liquid (IL) under electric currents have also been studied. Results showed that the GPCMCs exhibit excellent comprehensive mechanical and tribological properties than the PCMCs with homogenous pore structure. The coefficient of friction (COF) values and wear rates of PCMCs under dry friction are higher, and increase with the increase of applied voltages, and those with IL lubricant under various applied voltages are much lower and exhibit excellent electronically controlled effects. This is because that IL stored in PCMCs and GPCMCs can be released under external electrical and frictional stimulations improving the tribological performance greatly. This work provides a strategy to fabricate sliding electrical contact material with novel self-lubricating and enhanced mechanical properties.

Iron-bearing amendments, such as iron grit, are proved to be effective amendments for the remediation of arsenic- (As-) contaminated soils. In present study, the effect of redox condition on As fractions in As-contaminated soils remediated by iron grit was investigated, and the bioaccessibility of As in soils under anoxic condition was evaluated. Results showed that the labile fractions of As in soils decreased significantly after the addition of iron grit, while the unlabile fractions of As increased rapidly, and the bioaccessibility of As was negligible after 180 d incubation. More labile fractions of As in iron-amended soils were transformed into less mobilizable or unlabile fractions with the contact time. Correspondingly, the bioaccessibility of As in iron-amended soils under the aerobic condition was lower than that under the anoxic condition after 180 d incubation. The redistribution of loosely adsorbed fraction of As in soils occurred under the anoxic condition, which is likely ascribed to the reduction of As(V) to As(III) and the reductive dissolution of Fe-(hydr)oxides. The stabilization processes of As in iron-amended soils under the anoxic and aerobic conditions were characterized by two stages. The increase of crystallization of Fe oxides, decomposition of organic matter, molecular diffusion, and the occlusion within Fe-(hydr)oxides cocontrolled the transformation of As fractions and the stabilization process of As in iron-amended soils under different redox conditions. In terms of As bioaccessibility, the stabilization process of As in iron-amended soils was shortened under the aerobic condition in comparison with the anoxic condition.

BACKGROUND: On April 14, 2010, an earthquake registering 7.1 on the Richter scale shook Qinghai Province in southwest China. The earthquake caused numerous casualties and much damage. The epicenter, Yushu County, suffered the most severe damage. As a part of the psychological relief work, the present study evaluated the mental health statuses of the people affected and identified the mental disorder risk factors related to earthquakes. METHODS: Five hundred and five earthquake survivors living in Yushu County were investigated 3-4 months after the earthquake. Participant demographic data including gender, age, marital status, ethnicity, educational level, and religious beliefs were collected. The Earthquake-Specific Trauma Exposure Indicators assessed the intensity of exposure to trauma during the earthquake. The PTSD Checklist-Civilian version (PCL-C) and the Hopkins Symptoms Checklist-25 (HSCL-25) assessed the symptoms and prevalence rates of probable Posttraumatic Stress Disorder (PTSD) as well as anxiety and depression, respectively. The Perceived Social Support Scale (PSSS) evaluated subjective social support. RESULTS: The prevalence rates of probable PTSD, anxiety, and depression were 33.7%, 43.8% and 38.6%, respectively. Approximately one fifth of participants suffered from all three conditions. Individuals who were female, felt initial fear during the earthquake, and had less social support were the most likely to have poor mental health. CONCLUSIONS: The present study revealed that there are serious mental problems among the hard-hit survivors of the Yushu earthquake. Survivors at high risk for mental disorders should be specifically considered. The present study provides useful information for rebuilding and relief work.