High-throughput calculations combining machine learning to investigate the corrosion properties of binary Mg alloys

Magnesium(Mg)alloys have shown great prospects as both structural and biomedical materials,while poor corrosion resistance limits their further application.In this work,to avoid the time-consuming and laborious experiment trial,a high-throughput computational strategy based on first-principles calculations is designed for screening corrosion-resistant binary Mg alloy with intermetallics,from both the thermodynamic and kinetic perspectives.The stable binary Mg intermetallics with low equilibrium potential difference with respect to the Mg matrix are firstly identified.Then,the hydrogen adsorption energies on the surfaces of these Mg intermetallics are calculated,and the corrosion exchange current density is further calculated by a hydrogen evolution reaction(HER)kinetic model.Several intermetallics,e.g.Y_(3)Mg,Y_(2)Mg and La_(5)Mg,are identified to be promising intermetallics which might effectively hinder the cathodic HER.Furthermore,machine learning(ML)models are developed to predict Mg intermetallics with proper hydrogen adsorption energy employing work function(W_(f))and weighted first ionization energy(WFIE).The generalization of the ML models is tested on five new binary Mg intermetallics with the average root mean square error(RMSE)of 0.11 eV.This study not only predicts some promising binary Mg intermetallics which may suppress the galvanic corrosion,but also provides a high-throughput screening strategy and ML models for the design of corrosion-resistant alloy,which can be extended to ternary Mg alloys or other alloy systems.

Distribution properties of airflow in the full envelope type maize stalk chopping chamber

Chopped and spread maize stalks improve soil structure and fertility. However, because of the absence of research on airflow distribution in the chopping chamber, improvement of the spreading uniformity of chopped stalks has been limited. Therefore, in this study, computational fluid dynamics (CFD) technology was applied to analyze the influence of structural and operational parameters of the chopping and spreading machine on the velocity, pressure, and turbulent kinetic energy distribution of airflow in the chopping chamber. The experimental factors considered were the relative position angle (RPA) between the collecting-chopping shaft and the sliding-supporting shaft, working velocity (WV) of the chopping chamber, and rotational velocity of the collecting-chopping blade (RVCCB). The results revealed that RPA and RVCCB had a significant influence on the maximum negative pressure in the inlet (MNPI), the proportion of negative pressure area at inlet (PNPAI), and the maximum pressure drop at inlet and outlet (MPDIO). Additionally, RVCCB had a strong influence on the maximum velocity, average velocity, and velocity variation coefficient of airflow at the outlet. Moreover, maximum turbulence (MT) and maximum turbulent kinetic energy dissipation rate (MTKEDR) showed a positive relationship with RVCCB. To determine the values of RPA, RVCCB, and WV, a multivariate parameters optimization regression model was constructed, which yielded the optimal values of 15°, 1800 r/min, and 0.50 m/s, respectively. Subsequently, a hyperbolic spiral-type guiding shell with an arc length of 90° was designed to enhance the uniform distribution of airflow in the chopping chamber. Finally, a validation experiment of airflow distribution was conducted. The results showed that the velocity difference between the simulation and the validation experiment was less than 15%, indicating the accuracy of CFD simulation, and the spreading uniformities of the chopped stalks were better than national standards. These findings can serve as technical and theoretical support for the design and optimization of chopping and spreading machines.

Ag-catalyzed GaSb nanowires for flexible near-infrared photodetectors

High-quality narrow bandgap semiconductors nanowires(NWs)challenge the flexible near-infrared(NIR)photodetectors in next-generation imaging,data communication,environmental monitoring,and bioimaging applications.In this work,complementary metal oxide semiconductor-compatible metal of Ag is deposited on glass as the growth catalyst for the surfactantassisted chemical vapor deposition of GaSb NWs.The uniform morphology,balance stoichiometry,high-quality crystallinity,and phase purity of as-prepared NWs are checked by scanning electron microscopy,energy dispersive X-ray spectroscopy,high-resolution transmission electron microscopy,and X-ray diffraction.The electrical properties of as-prepared NWs are studied by constructing back-gated field-effect-transistors,displaying a high I_(on)/I_(off) ratio of 10^(4) and high peak hole mobility of 400 cm^(2)/(V·s).Benefiting from the excellent electrical and mechanical flexibility properties,the as-fabricated NW flexible NIR photodetector exhibits high sensitivity and excellent photoresponse,with responsivity as high as 618 A/W and detectivity as high as 6.7×10^(10) Jones.Furthermore,there is no obvious decline in NIR photodetection behavior,even after parallel and perpendicular folding with 1200 cycles.

Control of the stress field on shallow seafloor hydrothermal paths:A case study of the TAG hydrothermal field

The stress state and rock mechanical properties govern the growth of faults and fractures,which constitute shallow hydrothermal pathways and control the distribution of seafloor massive sulfide(SMS)mounds in the seafloor hydrothermal field.The stress field has an important influence on the formation and persistence of hydrothermal pathways.Based on multibeam bathymetric data from the Trans-Atlantic Geotraverse(TAG)field,we establish two three-dimensional geological models with different scales to simulate the stress field,which investigate the characteristics of hydrothermal pathways and associated SMS mounds.The simulation results show that oblique faults and fissures form in the tensile stress zone and that mounds,including active and inactive hydrothermal mounds form in the compressive stress zone.Fault activity,which is related to the stress field,affects the opening and closing of hydrothermal channels and changes the permeability structure of subseafloor wall rock.Therefore,the stress field controls the development and persistence of shallow hydrothermal pathways.The features of shallow hydrothermal pathways in the stress field can provide geomechanical information that is useful for identifying favorable zone for SMS deposit formation.

Toxic Effects of Four Commonly-used Agrochemicals on Arma chinensis and Picromerus lewisi

This study was conducted to investigate the toxic effects of four different agrochemicals on Arma chinensis and Picromerus lewisi . Cypermethrin·phoxim, imidacloprid and fenvalerate had higher toxic effects on A. chinensis and P. lewisi . After the application of the agrochemicals, the released stink bugs could not well survive and propagate. Though the herbicide （glyphosate ammonium） had no direct toxic effects on A. chinensis and P. lewisi , their survival and propagation were affected after the application of the herbicide into natural environment. Therefore, to ensure better survival and propagation of the two kinds of stink bugs in natural environment, local agrochemical management should be strengthened, and the concept of green environmental protection should be constructed and popularized.

Deformable Textile‑Structured Triboelectric Nanogenerator Knitted with Multifunctional Sensing Fibers for Biomechanical Energy Harvesting

Fibers and textiles that harvest mechanical energy via the triboelectric effect are promising candidates as power supplies for wearable electronics.However,triboelectric fibers and textiles are often hindered by problems such as complex fabrication processes,limited length,performances below the state-of-the-art of 2D planar configurations,etc.Here,we demonstrated a scalable fabrication of core-sheath-structured elastomer triboelectric fibers that combine silicone hollow tubes with gelelectrodes.Gel-electrodes were fabricated via a facile freeze–thawing process of blending polyvinyl alcohol(PVA),gelatin,glycerin,poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate)(PEDOT:PSS),and sodium chloride(NaCl).Such fibers can also be knitted into deformable triboelectric nanogenerator textiles with high electrical outputs up to 106 V and 0.8μA,which could work as reliable power supplies for small electronics.Moreover,we demonstrated fabric materials recognition,Morse code communication,and human-motion-recognition capabilities,making such triboelectric fiber platform an exciting avenue for multifunctional wearable systems and human–machine interaction.

Leaf-meridian bio-inspired nanofibrous electronics with uniform distributed microgrid and 3D multi-level structure for wearable applications

The interface between the active electronic and its osculatory target dominates the sensing response of high-sensitivity sensors.However,the interface properties are difficult to be adjusted and preserved owing to the limited strategies for surface engineering.In this work,inspired by nature frond leaf,a spatial multi-level nanofibrous membrane with grid-like microstructure of uniform distribution was fabricated,in which carboxylated carbon nanotubes(CCNTs)/poly(3,4-ethylenedioxythiophene)(PEDOT)was modified onto the surface of grid-like polyurethane(PU)nanofiber via the combination of metal mesh template,in situ polymerization and ultrasonic treatment.Nanofibrous membrane enables a pressure sensor with high sensitivities(5.13 kPa−1),fast response/recovery time(80 ms and 120 ms),and ultralow detection limit of 1 Pa.In addition,as a scalable and integrable platform,we also demonstrate its multifunctional applications for electro-thermal conversion and energy harvesting.All these results indicate the proposed nanofibrous membrane may potentially be applied to next-generation wearable devices.

Research progress in non-aqueous low-temperature electrolytes for sodium-based batteries

With the increasing demand and striking upsurge in the price of lithium carbonate,sodium-ion batteries(SIBs)have gained significant attentions due to their abundance over lithium-ion batteries(LIBs).Some prototype SIBs have achieved great progress in terms of energy densities.Although SIBs show a relatively higher tolerance at the low temperature than LIBs due to the weaker cation–solvent interaction,the low-temperature performance of SIBs remains a critical challenge restricted by the electrolyte solidification and sluggish interphasial kinetics.In this review,we briefly cover the latest research progress in usable low-temperature electrolytes for SIBs.In the meantime,the mitigating mechanism and low-temperature performance of the electrolytes in different SIB configurations are also discussed.The merits and demerits of ether-based and carbonate-based electrolytes are compared to demonstrate their potential and limitations,thus providing application principles for ether-based and carbonate-based electrolytes at low temperatures to maximize their advantages.Furthermore,mitigation strategies for lowtemperature electrolytes are emphasized to guide the future electrolyte design.Finally,we provide some perspectives on the development of the low-temperature electrolytes for SIBs.