Achieving high-quality perovskite films without surface defects is regarded as a crucial target for the development of durable high-performance perovskite solar cells.Additive engineering is commonly employed to simul...Achieving high-quality perovskite films without surface defects is regarded as a crucial target for the development of durable high-performance perovskite solar cells.Additive engineering is commonly employed to simultaneously control the growth of perovskite crystals and passivate defects.Here,4-(trifluoromethyl)benzoic anhydride(4-TBA)composed of benzene rings functionalized with carbonyl and trifluoromethyl groups was used as an example additive to study the characteristics of additives used for producing high-quality perovskites and controlling their surface properties.The interaction between4-TBA and perovskite precursor materials was investigated using density functional theory(DFT)simulations.The electron-rich carbonyl group efficiently passivated the under-coordinated lead-ion defects.Additionally,hydrogen bonding between trifluoromethyl and organic cations prevents the generation of cation vacancies.Because of its intrinsic hydrophobicity,the trifluoromethyl group simultaneously improves the moisture and heat stability of the film.4-TBA serves as a universal modifier for various perovskite compositions.The power conversion efficiency(PCE)of inverted perovskite solar cells(PSCs)based on methylammonium(MA)with 4-TBA was improved from 16.15%to 19.28%.Similarly,the PCE of inverted PSCs based on a cesium formamidinium MA(CsFAMA)perovskite film increased from20.72%to 23.58%,upon addition of 4-TBA.Furthermore,the moisture and thermal stability of 4-TBAtreated films and devices was significantly enhanced,along with prolonged device performance.Our work provides guidance on selecting the structure and functional groups that are essential for surface defect passivation and the production of high-quality perovskites.展开更多
Isothermal compression tests were used to establish constitutive models of the hot deformation of GH4742 superalloy. The microstructural evolution of double cone samples with large strain gradients during hot deformat...Isothermal compression tests were used to establish constitutive models of the hot deformation of GH4742 superalloy. The microstructural evolution of double cone samples with large strain gradients during hot deformation and subsequent solvus treatment was studied. The results showed that the grain size during dynamic recrystallization (DRX) did not exceed 6 μm, and the volume fraction during DRX did not exceed 45% at all reduction rates when it deformed below the γ′ solvus temperature (1080 ℃). When deformed near the γ′ solvus temperature (1110 ℃), the volume fraction and grain size increase significantly during DRX due to the dissolution and coarsening of some γ′ precipitates. When deformed above the γ′ solvus temperature (1140 ℃), even at a high reduction rate of 20 mm/s, the volume fraction during DRX reached 75%, and the grain size during DRX increased to 25 μm. At a reduction rate of 0.5 mm/s, the grain size during DRX reached 65 μm. When the sample is deformed below the γ′ solvus temperature (1080 ℃), stored strain energy accumulates in the sample, which is beneficial for the development of post dynamic recrystallization during subsequent subsolvus heat treatment, resulting in a noticeable increase in the recrystallization volume fraction. The recrystallization volume fraction of predeformed samples deformed at 1110 and 1140 ℃, followed by subsolvus heat treatment, was almost unchanged. The microstructure of the predeformed sample following supersolvus heat treatment consists of coarse equiaxed grains.展开更多
Perovskite solar cells(PSCs)have developed rapidly,positioning them as potential candidates for nextgeneration renewable energy sources.However,conventional trial-and-error approaches and the vast compositional parame...Perovskite solar cells(PSCs)have developed rapidly,positioning them as potential candidates for nextgeneration renewable energy sources.However,conventional trial-and-error approaches and the vast compositional parameter space continue to pose challenges in the pursuit of exceptional performance and high stability of perovskite-based optoelectronics.The increasing demand for novel materials in optoelectronic devices and establishment of substantial databases has enabled data-driven machinelearning(ML)approaches to swiftly advance in the materials field.This review succinctly outlines the fundamental ML procedures,techniques,and recent breakthroughs,particularly in predicting the physical characteristics of perovskite materials.Moreover,it highlights research endeavors aimed at optimizing and screening materials to enhance the efficiency and stability of PSCs.Additionally,this review highlights recent efforts in using characterization data for ML,exploring their correlations with material properties and device performance,which are actively being researched,but they have yet to receive significant attention.Lastly,we provide future perspectives,such as leveraging Large Language Models(LLMs)and text-mining,to expedite the discovery of novel perovskite materials and expand their utilization across various optoelectronic fields.展开更多
With the rise of artificial intelligence(AI),neuromorphic sensory systems that emulate the five basic human sensations including tactility,audition,olfaction,gustation,and vision have attracted significant attention.I...With the rise of artificial intelligence(AI),neuromorphic sensory systems that emulate the five basic human sensations including tactility,audition,olfaction,gustation,and vision have attracted significant attention.In particular,research on integrating sensors with artificial synapses is being carried out extensively.These studies offer valuable opportunities for making another breakthrough in AI technology,including autonomous systems,real-time monitoring systems,and human-machine interactions.In this review,we introduce promising reports of neuromorphic sensory systems.Specifically,the core sensing material,device architecture,fabrication process,and applications of the proposed systems are presented in detail.Finally,the unsolved challenges and the prospects of neuromorphic sensory systems are discussed.展开更多
The bandgap is a key parameter for understanding and designing hybrid perovskite material properties,as well as developing photovoltaic devices.Traditional bandgap calculation methods like ultravioletvisible spectrosc...The bandgap is a key parameter for understanding and designing hybrid perovskite material properties,as well as developing photovoltaic devices.Traditional bandgap calculation methods like ultravioletvisible spectroscopy and first-principles calculations are time-and power-consuming,not to mention capturing bandgap change mechanisms for hybrid perovskite materials across a wide range of unknown space.In the present work,an artificial intelligence ensemble comprising two classifiers(with F1 scores of 0.9125 and 0.925)and a regressor(with mean squared error of 0.0014 eV)is constructed to achieve high-precision prediction of the bandgap.The bandgap perovskite dataset is established through highthroughput prediction of bandgaps by the ensemble.Based on the self-built dataset,partial dependence analysis(PDA)is developed to interpret the bandgap influential mechanism.Meanwhile,an interpretable mathematical model with an R^(2)of 0.8417 is generated using the genetic programming symbolic regression(GPSR)technique.The constructed PDA maps agree well with the Shapley Additive exPlanations,the GPSR model,and experiment verification.Through PDA,we reveal the boundary effect,the bowing effect,and their evolution trends with key descriptors.展开更多
This study investigates zinc’s(Zn)key role in enhancing the precipitation kinetics and refinement of Mg_(17)Al_(12)and Mg_(2)Sn phases in magnesium alloys through trace sodium(Na)additions.Magnesium alloys with varyi...This study investigates zinc’s(Zn)key role in enhancing the precipitation kinetics and refinement of Mg_(17)Al_(12)and Mg_(2)Sn phases in magnesium alloys through trace sodium(Na)additions.Magnesium alloys with varying compositions of aluminum(Al),tin(Sn),Zn,and Na were prepared and aged at 453 K.Microstructural analyses were conducted using transmission electron microscopy(TEM),scanning transmission electron microscopy(STEM),and atom probe tomography(APT).Trace additions of Na significantly enhanced the precipitation responses of both Mg_(17)Al_(12)and Mg_(2)Sn phases.When Zn was co-added with Na,as in the ATZ641N3 alloy(Mg–6Al–4Sn–1Zn–0.3Na),there was a pronounced refinement in precipitate morphology and acceleration of precipitation kinetics.The ATZ641N3 alloy achieved a peak hardness of 103 Hv at 36 hours,compared to 91 Hv at 72 hours for the ATZ641 alloy without Na.The simultaneous addition of Zn and Na led to the formation of Sn–Na–Zn particles that acted as effective nucleation sites for Mg_(2)Sn,promoting aluminum partitioning and accelerating the precipitation of Mg_(17)Al_(12)through Al-rich regions.Additionally,Zn and Na co-segregated within the Mg_(17)Al_(12)phase,reducing misfit strain caused by Zn substitution and improving precipitate stability and refinement.These findings highlight Zn’s critical role,alongside trace Na additions,in refining and accelerating the precipitation of Mg_(17)Al_(12)and Mg_(2)Sn phases,thereby enhancing the age-hardening response of magnesium alloys.展开更多
The limited charge extraction efficiency and suboptimal energy-level alignment of poly(3,4-ethylenediox ythiophene)polystyrene sulfonate(PEDOT:PSS)as a hole transport layer restrict its performance in solar cell appli...The limited charge extraction efficiency and suboptimal energy-level alignment of poly(3,4-ethylenediox ythiophene)polystyrene sulfonate(PEDOT:PSS)as a hole transport layer restrict its performance in solar cell applications.In this study,we developed effective copper-ion(Cu(Ⅱ))-modified oxyl-terminated melem two-dimensional(2D)nanodisks(Cu(Ⅱ)@OMN)that improved the performance of PEDOT:PSS as a representative hole-transport layer(HTL)in organic and perovskite solar cells.Based on theoretical calculations and experimental data,the interaction between Cu(Ⅱ)@OMN and PEDOT or PSS led to electron redistribution in PEDOT:PSS and the dissociation of PEDOT and PSS,promoting enhanced charge extraction and transfer.In addition,the work function of the Cu(Ⅱ)@OMN-PEDOT:PSS is modified to achieve a more beneficial energy-level alignment,thereby facilitating improved hole transport and inhibited nonradiative recombination.Methylammonium(MA)-based perovskite and organic binary PM6:Y6solar cells achieved power conversion efficiencies(PCEs)of 19.21% and 17.15%,respectively.These PCEs are among the highest reported for MA-based perovskite and binary PM6:Y6 organic solar cells that use 2D nanomaterial-modified PEDOT:PSS,demonstrating the potential of Cu(Ⅱ)@OMN in solar cell applications.展开更多
The latest developments in bio-inspired neuromorphic vision sensors can be summarized in 3 keywords:smaller,faster,and smarter.(1)Smaller:Devices are becoming more compact by integrating previously separated component...The latest developments in bio-inspired neuromorphic vision sensors can be summarized in 3 keywords:smaller,faster,and smarter.(1)Smaller:Devices are becoming more compact by integrating previously separated components such as sensors,memory,and processing units.As a prime example,the transition from traditional sensory vision computing to in-sensor vision computing has shown clear benefits,such as simpler circuitry,lower power consumption,and less data redundancy.(2)Swifter:Owing to the nature of physics,smaller and more integrated devices can detect,process,and react to input more quickly.In addition,the methods for sensing and processing optical information using various materials(such as oxide semiconductors)are evolving.(3)Smarter:Owing to these two main research directions,we can expect advanced applications such as adaptive vision sensors,collision sensors,and nociceptive sensors.This review mainly focuses on the recent progress,working mechanisms,image pre-processing techniques,and advanced features of two types of neuromorphic vision sensors based on near-sensor and in-sensor vision computing methodologies.展开更多
Friction stir processing （FSP） was used to incorporate SiC particles into the matrix of A356 Al alloy to form composite material. Constant tool rotation speed of 1800 r/min and travel speed of 127 mm/min were used i...Friction stir processing （FSP） was used to incorporate SiC particles into the matrix of A356 Al alloy to form composite material. Constant tool rotation speed of 1800 r/min and travel speed of 127 mm/min were used in this study. The base metal （BM） shows the hypoeutectic Al-Si dendrite structure. The microstructure of the stir zone （SZ） is very different from that of the BM. The eutectic Si and SiC particles are dispersed homogeneously in primary Al solid solution. The thermo-mechanically affected zone （TMAZ）, where the original microstructure is greatly deformed, is characterized by dispersed eutectic Si and SiC particles aligned along the rotational direction of the tool. The hardness of the SZ shows higher value than that of the BM because some defects are remarkably reduced and the eutectic Si and SiC particles are dispersed over the SZ.展开更多
The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was fas...The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was faster than that in air above 700℃, due to the formation of the Fe0.975S sulfide. The corrosion rate of the spheroidal graphite cast iron was similar to that of the flake graphite cast iron.展开更多
A body frame composed of thin sheet metal is a crucial structure that determines the safety performance of a vehicle.Designing a correct weight and high-performance automotive body is an emerging engineering problem.T...A body frame composed of thin sheet metal is a crucial structure that determines the safety performance of a vehicle.Designing a correct weight and high-performance automotive body is an emerging engineering problem.To improve the performance of the automotive frame,we attempt to reconstruct its design criteria based on statistical and mechanical approaches.At first,a fundamental study on the frame strength is conducted and a cross-sectional shape optimization problem is developed for designing the cross-sectional shape of an automobile frame having a very high mass efficiency for strength.Shape optimization is carried out using the nonlinear finite element method and a meta-modeling-based genetic algorithm.Data analysis of the obtained set of optimal results is performed to identify the dominant design variables by employing the smoothing spline analysis of variance,the principal component analysis,and the self-organizing map technique.The relationship between the cross-sectional shape and the objective function is also analyzed by hierarchical clustering.A design guideline is obtained from these statistical approach results.A comparison between the statistically obtained design guideline and the conventional one based on the designers’experience is performed based on mechanical interpretation of the optimal cross-sectional frame.Finally,a mechanically reasonable new general-purpose design guideline is proposed for the cross-sectional shape of the automotive frame.展开更多
Friction stir processing of AA6061-T4 alloy with SiC particles was successfully carried out.SiC particles were uniformly dispersed into an AA6061-T4 matrix.Also SiC particles promoted the grain refinement of the AA606...Friction stir processing of AA6061-T4 alloy with SiC particles was successfully carried out.SiC particles were uniformly dispersed into an AA6061-T4 matrix.Also SiC particles promoted the grain refinement of the AA6061-T4 matrix by FSP.The mean grain size of the stir zone (SZ) with the SiC particles was obviously smaller than that of the stir zone without the SiC particles.The microhardness of the SZ with the SiC particles reached about HV80 due to the grain refinement and the distribution of the SiC particles.展开更多
Near infrared-II(NIR-II)dyes have unique advantages in biomedical applications owing to the powerful ability in penetrating biological tissues.Herein,NIR-II aza-BODIPY dye,QLD-BDP,was developed with julolidine at 1,7-...Near infrared-II(NIR-II)dyes have unique advantages in biomedical applications owing to the powerful ability in penetrating biological tissues.Herein,NIR-II aza-BODIPY dye,QLD-BDP,was developed with julolidine at 1,7-sites and p-dimethylaminophenyl group at 3,5-sites.According to X-ray analysis,QLD-BDP exhibits significant distortion,and this molecule appears a bowl shaped structure.The photothermal conversion efficiency of the self-assembled QLD-BDP nanoparticles(QLD-BDP-NPs)can reach 50.5%,with maximum emission at 998 nm by the aggregate.QLD-BDP-NPs can cause the complete destruction of 4T1multicellular spheroids(MCSs),indicating a photothermal therapy(PTT)effect.展开更多
Layered-type metal phosphates of BaNb_(2-x)Ta_(x)P_(2)O_(11)(x=0,0.5,1.0,1.5,and 2.0)were synthesized using a solid-state reaction method.The photophysical,optical,and photocatalytic hydrogen production properties of ...Layered-type metal phosphates of BaNb_(2-x)Ta_(x)P_(2)O_(11)(x=0,0.5,1.0,1.5,and 2.0)were synthesized using a solid-state reaction method.The photophysical,optical,and photocatalytic hydrogen production properties of the resulting powders were investigated for the first time.Phase-pure and homogeneous powders with irregular morphologies were obtained at a calcination temperature of 1200℃.As the Ta content increased,the interlayer distance along the c-axis increased by up to 0.14%.Additionally,the optical bandgap values increased from 3.32 to 3.59 eV.The energy band positions were estimated from the Mott–Schottky measurements.BaNb_(2)P_(2)O_(11)(x=0)exhibited the lowest conduction band edge position(-0.14 V vs.the normal hydrogen electrode,NHE),which is located above the water reduction potential(0.0 V vs.NHE).In comparison,BaTa_(2)P_(2)O_(11)(x=2.0)exhibited the highest conduction band edge position(-0.29 V vs.NHE),comparable to that of TiO_(2).The photocatalytic activity for hydrogen produced from splitting water was measured under ultraviolet light irradiation.Notably,BaTa_(2)P_(2)O_(11)exhibited the highest activity(7.3μmol/h),which was 15 and 10 times larger than BaNb_(2)P_(2)O_(11)(0.5μmol/h)and nano-TiO_(2)(0.7μmol/h),respectively.The activity of BaTa_(2)P_(2)O_(11)increased to 24.4μmol/h after deposition of the NiO_(x)co-catalyst(1 wt.%),which remained stable during continuous operation(~35 h).展开更多
With the increasing spotlight in electric vehicles,there is a growing demand for high-energy-density batteries to enhance driving range.Consequently,several studies have been conducted on high-energy-density LiNi_(x)C...With the increasing spotlight in electric vehicles,there is a growing demand for high-energy-density batteries to enhance driving range.Consequently,several studies have been conducted on high-energy-density LiNi_(x)Co_(y)Mn_(z)O_(2)cathodes.However,there is a limit to permanent performance deterioration because of side reactions caused by moisture in the atmosphere and continuous microcracks during cycling as the Ni content to express high energy increases and the content of Mn and Co that maintain structural and electrochemical stabilization decreases.The direct modification of the surface and bulk regions aims to enhance the capacity and long-term performance of high-Ni cathode materials.Therefore,an efficient modification requires a study based on a thorough understanding of the degradation mechanisms in the surface and bulk region.In this review,a comprehensive analysis of various modifications,including doping,coating,concentration gradient,and single crystals,is conducted to solve degradation issues along with an analysis of the overall degradation mechanism occurring in high-Ni cathode materials.It also summarizes recent research developments related to the following modifications,aims to provide notable points and directions for post-studies,and provides valuable references for the commercialization of stable high-energy-density cathode materials.展开更多
In the H-mode experiments conducted on the Experimental Advanced Superconducting Tokamak(EAST),fluctuations induced by the so-called edge localized modes(ELMs)are captured by a high-speed vacuum ultraviolet(VUV)imagin...In the H-mode experiments conducted on the Experimental Advanced Superconducting Tokamak(EAST),fluctuations induced by the so-called edge localized modes(ELMs)are captured by a high-speed vacuum ultraviolet(VUV)imaging system.Clear field line-aligned filamentary structures are analyzed in this work.Ion transport induced by ELM filaments in the scrape-off layer(SOL)under different discharge conditions is analyzed by comparing the VUV signals with the divertor probe signals.It is found that convective transport along open field lines towards the divertor target dominates the parallel ion particle transport mechanism during ELMs.The toroidal mode number of the filamentary structure derived from the VUV images increases with the electron density pedestal height.The analysis of the toroidal distribution characteristics during ELM bursts reveals toroidal asymmetry.The influence of resonance magnetic perturbation(RMP)on the ELM size is also analyzed using VUV imaging data.When the phase difference of the coil changes periodically,the widths of the filaments change as well.Additionally,the temporal evolution of the ELMs on the VUV signals provides rise time and decay time for each single ELM event,and the results indicate a negative correlation trend between these two times.展开更多
Three-dimensional(3D) equilibrium calculations, including the plasma rotation shielding effect to resonant magnetic perturbations(RMPs) produced by the island divertor(ID) coils, were carried out using the HINT and MA...Three-dimensional(3D) equilibrium calculations, including the plasma rotation shielding effect to resonant magnetic perturbations(RMPs) produced by the island divertor(ID) coils, were carried out using the HINT and MARS-F codes on J-TEXT. Validation of 3D equilibrium calculations with experimental observations demonstrates that the shielding effect will prevent the penetration of the edge m/n = 3/1 mode component when the ID coil current is 4 k A, while change the size of magnetic islands once the current exceeds the penetration threshold. This indicates that equilibrium calculations including the plasma rotation shielding effect to RMPs can lead to better agreements with experimental observations compared to the vacuum approximation method. Additionally, the magnetic topology at the boundary undergoes changes,impacting the interaction between the plasma and the target plate. These results may be important in understanding RMP effects on edge transport and magnetohydrodynamic(MHD)instability control, as well as divertor heat and particle flux distribution control.展开更多
Herein,a layer of molybdenum oxide(MoO_(x)),a transition metal oxide(TMO),which has outstanding catalytic properties in combination with a carbonbased thin film,is modified to improve the hydrogen production performan...Herein,a layer of molybdenum oxide(MoO_(x)),a transition metal oxide(TMO),which has outstanding catalytic properties in combination with a carbonbased thin film,is modified to improve the hydrogen production performance and protect the MoO_(x)in acidic media.A thin film of graphene is transferred onto the MoO_(x)layer,after which the graphene structure is doped with N and S atoms at room temperature using a plasma doping method to modify the electronic structure and intrinsic properties of the material.The oxygen functional groups in graphene increase the interfacial interactions and electrical contacts between graphene and MoO_(x).The appearance of surface defects such as oxygen vacancies can result in vacancies in MoO_(x).This improves the electrical conductivity and electrochemically accessible surface area.Increasing the number of defects in graphene by adding dopants can significantly affect the chemical reaction at the interfaces and improve the electrochemical performance.These defects in graphene play a crucial role in the adsorption of H^(+)ions on the graphene surface and their transport to the MoO_(x)layer underneath.This enables MoO_(x)to participate in the reaction with the doped graphene.N^(‐)and S^(‐)doped graphene(NSGr)on MoO_(x)is active in acidic media and performs well in terms of hydrogen production.The initial overpotential value of 359 mV for the current density of−10 mA/cm^(2)is lowered to 228 mV after activation.展开更多
This paper proposes a parameter determination method of distribution voltage regulators load ratio control transformers （LRT） and step voltage regulators （SVR） considering the tap change and voltage profile. The m...This paper proposes a parameter determination method of distribution voltage regulators load ratio control transformers （LRT） and step voltage regulators （SVR） considering the tap change and voltage profile. The method takes two procedures in order to simplify the optimization problem and to reduce calculation time. One is to simultaneously determine the control parameters of LRT and SVR minimizing voltage violations and voltage variations. The algorithm is based on particle swarm optimization （PSO）, which is one of non-linear optimization methods by using a concept of swarm intelligence. Another is to determine the dead-band width of LRT and SVR on the basis of bi-evaluation of tap change and voltage margin. The concept of a Pareto optimal solution is used for the decision of the best dead-band width. As the results of numerical simulations using distribution network model, the validity of the proposed method has been affirmed.展开更多
基金supported by a Research Grant of Pukyong National University(2023)。
文摘Achieving high-quality perovskite films without surface defects is regarded as a crucial target for the development of durable high-performance perovskite solar cells.Additive engineering is commonly employed to simultaneously control the growth of perovskite crystals and passivate defects.Here,4-(trifluoromethyl)benzoic anhydride(4-TBA)composed of benzene rings functionalized with carbonyl and trifluoromethyl groups was used as an example additive to study the characteristics of additives used for producing high-quality perovskites and controlling their surface properties.The interaction between4-TBA and perovskite precursor materials was investigated using density functional theory(DFT)simulations.The electron-rich carbonyl group efficiently passivated the under-coordinated lead-ion defects.Additionally,hydrogen bonding between trifluoromethyl and organic cations prevents the generation of cation vacancies.Because of its intrinsic hydrophobicity,the trifluoromethyl group simultaneously improves the moisture and heat stability of the film.4-TBA serves as a universal modifier for various perovskite compositions.The power conversion efficiency(PCE)of inverted perovskite solar cells(PSCs)based on methylammonium(MA)with 4-TBA was improved from 16.15%to 19.28%.Similarly,the PCE of inverted PSCs based on a cesium formamidinium MA(CsFAMA)perovskite film increased from20.72%to 23.58%,upon addition of 4-TBA.Furthermore,the moisture and thermal stability of 4-TBAtreated films and devices was significantly enhanced,along with prolonged device performance.Our work provides guidance on selecting the structure and functional groups that are essential for surface defect passivation and the production of high-quality perovskites.
基金supported by the National Science and Technology Major Project of China(2017-VI-0018-0090).
文摘Isothermal compression tests were used to establish constitutive models of the hot deformation of GH4742 superalloy. The microstructural evolution of double cone samples with large strain gradients during hot deformation and subsequent solvus treatment was studied. The results showed that the grain size during dynamic recrystallization (DRX) did not exceed 6 μm, and the volume fraction during DRX did not exceed 45% at all reduction rates when it deformed below the γ′ solvus temperature (1080 ℃). When deformed near the γ′ solvus temperature (1110 ℃), the volume fraction and grain size increase significantly during DRX due to the dissolution and coarsening of some γ′ precipitates. When deformed above the γ′ solvus temperature (1140 ℃), even at a high reduction rate of 20 mm/s, the volume fraction during DRX reached 75%, and the grain size during DRX increased to 25 μm. At a reduction rate of 0.5 mm/s, the grain size during DRX reached 65 μm. When the sample is deformed below the γ′ solvus temperature (1080 ℃), stored strain energy accumulates in the sample, which is beneficial for the development of post dynamic recrystallization during subsequent subsolvus heat treatment, resulting in a noticeable increase in the recrystallization volume fraction. The recrystallization volume fraction of predeformed samples deformed at 1110 and 1140 ℃, followed by subsolvus heat treatment, was almost unchanged. The microstructure of the predeformed sample following supersolvus heat treatment consists of coarse equiaxed grains.
基金supported by the Ministry of Science and ICT(MSIT)of the Republic of Korea(00302646)supported by the National Research Foundation of Korea grant funded by the Korean Government(MSIT)(NRF-2022R1A4A1019296,1345374646,2022M3J1A1064315).
文摘Perovskite solar cells(PSCs)have developed rapidly,positioning them as potential candidates for nextgeneration renewable energy sources.However,conventional trial-and-error approaches and the vast compositional parameter space continue to pose challenges in the pursuit of exceptional performance and high stability of perovskite-based optoelectronics.The increasing demand for novel materials in optoelectronic devices and establishment of substantial databases has enabled data-driven machinelearning(ML)approaches to swiftly advance in the materials field.This review succinctly outlines the fundamental ML procedures,techniques,and recent breakthroughs,particularly in predicting the physical characteristics of perovskite materials.Moreover,it highlights research endeavors aimed at optimizing and screening materials to enhance the efficiency and stability of PSCs.Additionally,this review highlights recent efforts in using characterization data for ML,exploring their correlations with material properties and device performance,which are actively being researched,but they have yet to receive significant attention.Lastly,we provide future perspectives,such as leveraging Large Language Models(LLMs)and text-mining,to expedite the discovery of novel perovskite materials and expand their utilization across various optoelectronic fields.
基金supported by the National Research Foundation of Korea(NRF)Grant funded by the Korea Government(Ministry of Science and ICT)(No.NRF-2022R1A2C2010774)by the GRRC program of Gyeonggi Province(GRRC Sungkyunkwan 2023-B04)by Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(P0020967,Advanced Training Program for Smart Sensor Engineers).
文摘With the rise of artificial intelligence(AI),neuromorphic sensory systems that emulate the five basic human sensations including tactility,audition,olfaction,gustation,and vision have attracted significant attention.In particular,research on integrating sensors with artificial synapses is being carried out extensively.These studies offer valuable opportunities for making another breakthrough in AI technology,including autonomous systems,real-time monitoring systems,and human-machine interactions.In this review,we introduce promising reports of neuromorphic sensory systems.Specifically,the core sensing material,device architecture,fabrication process,and applications of the proposed systems are presented in detail.Finally,the unsolved challenges and the prospects of neuromorphic sensory systems are discussed.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(Grant number:RS-2025-02316700,and RS-2025-00522430)the China Scholarship Council Program。
文摘The bandgap is a key parameter for understanding and designing hybrid perovskite material properties,as well as developing photovoltaic devices.Traditional bandgap calculation methods like ultravioletvisible spectroscopy and first-principles calculations are time-and power-consuming,not to mention capturing bandgap change mechanisms for hybrid perovskite materials across a wide range of unknown space.In the present work,an artificial intelligence ensemble comprising two classifiers(with F1 scores of 0.9125 and 0.925)and a regressor(with mean squared error of 0.0014 eV)is constructed to achieve high-precision prediction of the bandgap.The bandgap perovskite dataset is established through highthroughput prediction of bandgaps by the ensemble.Based on the self-built dataset,partial dependence analysis(PDA)is developed to interpret the bandgap influential mechanism.Meanwhile,an interpretable mathematical model with an R^(2)of 0.8417 is generated using the genetic programming symbolic regression(GPSR)technique.The constructed PDA maps agree well with the Shapley Additive exPlanations,the GPSR model,and experiment verification.Through PDA,we reveal the boundary effect,the bowing effect,and their evolution trends with key descriptors.
基金supported by the Fundamental Research Program(PNKA130)of the Korea Institute of Materials Science,Republic of Korea。
文摘This study investigates zinc’s(Zn)key role in enhancing the precipitation kinetics and refinement of Mg_(17)Al_(12)and Mg_(2)Sn phases in magnesium alloys through trace sodium(Na)additions.Magnesium alloys with varying compositions of aluminum(Al),tin(Sn),Zn,and Na were prepared and aged at 453 K.Microstructural analyses were conducted using transmission electron microscopy(TEM),scanning transmission electron microscopy(STEM),and atom probe tomography(APT).Trace additions of Na significantly enhanced the precipitation responses of both Mg_(17)Al_(12)and Mg_(2)Sn phases.When Zn was co-added with Na,as in the ATZ641N3 alloy(Mg–6Al–4Sn–1Zn–0.3Na),there was a pronounced refinement in precipitate morphology and acceleration of precipitation kinetics.The ATZ641N3 alloy achieved a peak hardness of 103 Hv at 36 hours,compared to 91 Hv at 72 hours for the ATZ641 alloy without Na.The simultaneous addition of Zn and Na led to the formation of Sn–Na–Zn particles that acted as effective nucleation sites for Mg_(2)Sn,promoting aluminum partitioning and accelerating the precipitation of Mg_(17)Al_(12)through Al-rich regions.Additionally,Zn and Na co-segregated within the Mg_(17)Al_(12)phase,reducing misfit strain caused by Zn substitution and improving precipitate stability and refinement.These findings highlight Zn’s critical role,alongside trace Na additions,in refining and accelerating the precipitation of Mg_(17)Al_(12)and Mg_(2)Sn phases,thereby enhancing the age-hardening response of magnesium alloys.
基金supported by the Nano Material Technology Development Program(2021M3H4A1A02057007)funded by the Ministry of Science and ICT through the National Research Foundation of Koreasupported by the Basic Science Research Program through NRF funded by the Ministry of Education(2022R1A6A1A03051158,2022R1A2C4002248,RS-202300247069)。
文摘The limited charge extraction efficiency and suboptimal energy-level alignment of poly(3,4-ethylenediox ythiophene)polystyrene sulfonate(PEDOT:PSS)as a hole transport layer restrict its performance in solar cell applications.In this study,we developed effective copper-ion(Cu(Ⅱ))-modified oxyl-terminated melem two-dimensional(2D)nanodisks(Cu(Ⅱ)@OMN)that improved the performance of PEDOT:PSS as a representative hole-transport layer(HTL)in organic and perovskite solar cells.Based on theoretical calculations and experimental data,the interaction between Cu(Ⅱ)@OMN and PEDOT or PSS led to electron redistribution in PEDOT:PSS and the dissociation of PEDOT and PSS,promoting enhanced charge extraction and transfer.In addition,the work function of the Cu(Ⅱ)@OMN-PEDOT:PSS is modified to achieve a more beneficial energy-level alignment,thereby facilitating improved hole transport and inhibited nonradiative recombination.Methylammonium(MA)-based perovskite and organic binary PM6:Y6solar cells achieved power conversion efficiencies(PCEs)of 19.21% and 17.15%,respectively.These PCEs are among the highest reported for MA-based perovskite and binary PM6:Y6 organic solar cells that use 2D nanomaterial-modified PEDOT:PSS,demonstrating the potential of Cu(Ⅱ)@OMN in solar cell applications.
基金This work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.NRF-2019R1A2C2002447)This research also was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.NRF-2014R1A6A1030419)This work also was supported by Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(P0020967,Advanced Training Program for Smart Sensor Engineers).
文摘The latest developments in bio-inspired neuromorphic vision sensors can be summarized in 3 keywords:smaller,faster,and smarter.(1)Smaller:Devices are becoming more compact by integrating previously separated components such as sensors,memory,and processing units.As a prime example,the transition from traditional sensory vision computing to in-sensor vision computing has shown clear benefits,such as simpler circuitry,lower power consumption,and less data redundancy.(2)Swifter:Owing to the nature of physics,smaller and more integrated devices can detect,process,and react to input more quickly.In addition,the methods for sensing and processing optical information using various materials(such as oxide semiconductors)are evolving.(3)Smarter:Owing to these two main research directions,we can expect advanced applications such as adaptive vision sensors,collision sensors,and nociceptive sensors.This review mainly focuses on the recent progress,working mechanisms,image pre-processing techniques,and advanced features of two types of neuromorphic vision sensors based on near-sensor and in-sensor vision computing methodologies.
基金supported by a grant from the Fundamental R & D Program (No.10038688) for Core Technology of Materials funded by the Ministry of Knowledge Economy, Republic of Korea
文摘Friction stir processing （FSP） was used to incorporate SiC particles into the matrix of A356 Al alloy to form composite material. Constant tool rotation speed of 1800 r/min and travel speed of 127 mm/min were used in this study. The base metal （BM） shows the hypoeutectic Al-Si dendrite structure. The microstructure of the stir zone （SZ） is very different from that of the BM. The eutectic Si and SiC particles are dispersed homogeneously in primary Al solid solution. The thermo-mechanically affected zone （TMAZ）, where the original microstructure is greatly deformed, is characterized by dispersed eutectic Si and SiC particles aligned along the rotational direction of the tool. The hardness of the SZ shows higher value than that of the BM because some defects are remarkably reduced and the eutectic Si and SiC particles are dispersed over the SZ.
文摘The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was faster than that in air above 700℃, due to the formation of the Fe0.975S sulfide. The corrosion rate of the spheroidal graphite cast iron was similar to that of the flake graphite cast iron.
文摘A body frame composed of thin sheet metal is a crucial structure that determines the safety performance of a vehicle.Designing a correct weight and high-performance automotive body is an emerging engineering problem.To improve the performance of the automotive frame,we attempt to reconstruct its design criteria based on statistical and mechanical approaches.At first,a fundamental study on the frame strength is conducted and a cross-sectional shape optimization problem is developed for designing the cross-sectional shape of an automobile frame having a very high mass efficiency for strength.Shape optimization is carried out using the nonlinear finite element method and a meta-modeling-based genetic algorithm.Data analysis of the obtained set of optimal results is performed to identify the dominant design variables by employing the smoothing spline analysis of variance,the principal component analysis,and the self-organizing map technique.The relationship between the cross-sectional shape and the objective function is also analyzed by hierarchical clustering.A design guideline is obtained from these statistical approach results.A comparison between the statistically obtained design guideline and the conventional one based on the designers’experience is performed based on mechanical interpretation of the optimal cross-sectional frame.Finally,a mechanically reasonable new general-purpose design guideline is proposed for the cross-sectional shape of the automotive frame.
基金Project(10038688)supported by the Fundamental R&D Program for Core Technology of Materials Funded by the Ministry of Knowledge Economy,Republic of Korea
文摘Friction stir processing of AA6061-T4 alloy with SiC particles was successfully carried out.SiC particles were uniformly dispersed into an AA6061-T4 matrix.Also SiC particles promoted the grain refinement of the AA6061-T4 matrix by FSP.The mean grain size of the stir zone (SZ) with the SiC particles was obviously smaller than that of the stir zone without the SiC particles.The microhardness of the SZ with the SiC particles reached about HV80 due to the grain refinement and the distribution of the SiC particles.
基金supported by the National Natural Science Foundation of China(Nos.22078201,U1908202)Liaoning&Shenyang Key Laboratory of Functional Dye and Pigment(Nos.2021JH13/10200018,21–104–0–23)。
文摘Near infrared-II(NIR-II)dyes have unique advantages in biomedical applications owing to the powerful ability in penetrating biological tissues.Herein,NIR-II aza-BODIPY dye,QLD-BDP,was developed with julolidine at 1,7-sites and p-dimethylaminophenyl group at 3,5-sites.According to X-ray analysis,QLD-BDP exhibits significant distortion,and this molecule appears a bowl shaped structure.The photothermal conversion efficiency of the self-assembled QLD-BDP nanoparticles(QLD-BDP-NPs)can reach 50.5%,with maximum emission at 998 nm by the aggregate.QLD-BDP-NPs can cause the complete destruction of 4T1multicellular spheroids(MCSs),indicating a photothermal therapy(PTT)effect.
基金supported by the Basic Science Research Program through the National Research Foundation of Koreafunded by the Ministry of Science,ICT,and Future Planning(no.NRF2019R1A2C2002024)
文摘Layered-type metal phosphates of BaNb_(2-x)Ta_(x)P_(2)O_(11)(x=0,0.5,1.0,1.5,and 2.0)were synthesized using a solid-state reaction method.The photophysical,optical,and photocatalytic hydrogen production properties of the resulting powders were investigated for the first time.Phase-pure and homogeneous powders with irregular morphologies were obtained at a calcination temperature of 1200℃.As the Ta content increased,the interlayer distance along the c-axis increased by up to 0.14%.Additionally,the optical bandgap values increased from 3.32 to 3.59 eV.The energy band positions were estimated from the Mott–Schottky measurements.BaNb_(2)P_(2)O_(11)(x=0)exhibited the lowest conduction band edge position(-0.14 V vs.the normal hydrogen electrode,NHE),which is located above the water reduction potential(0.0 V vs.NHE).In comparison,BaTa_(2)P_(2)O_(11)(x=2.0)exhibited the highest conduction band edge position(-0.29 V vs.NHE),comparable to that of TiO_(2).The photocatalytic activity for hydrogen produced from splitting water was measured under ultraviolet light irradiation.Notably,BaTa_(2)P_(2)O_(11)exhibited the highest activity(7.3μmol/h),which was 15 and 10 times larger than BaNb_(2)P_(2)O_(11)(0.5μmol/h)and nano-TiO_(2)(0.7μmol/h),respectively.The activity of BaTa_(2)P_(2)O_(11)increased to 24.4μmol/h after deposition of the NiO_(x)co-catalyst(1 wt.%),which remained stable during continuous operation(~35 h).
文摘With the increasing spotlight in electric vehicles,there is a growing demand for high-energy-density batteries to enhance driving range.Consequently,several studies have been conducted on high-energy-density LiNi_(x)Co_(y)Mn_(z)O_(2)cathodes.However,there is a limit to permanent performance deterioration because of side reactions caused by moisture in the atmosphere and continuous microcracks during cycling as the Ni content to express high energy increases and the content of Mn and Co that maintain structural and electrochemical stabilization decreases.The direct modification of the surface and bulk regions aims to enhance the capacity and long-term performance of high-Ni cathode materials.Therefore,an efficient modification requires a study based on a thorough understanding of the degradation mechanisms in the surface and bulk region.In this review,a comprehensive analysis of various modifications,including doping,coating,concentration gradient,and single crystals,is conducted to solve degradation issues along with an analysis of the overall degradation mechanism occurring in high-Ni cathode materials.It also summarizes recent research developments related to the following modifications,aims to provide notable points and directions for post-studies,and provides valuable references for the commercialization of stable high-energy-density cathode materials.
基金supported in part by the National Key R&D Program of China(Nos.2019YFE03080200,2022YFE03030001 and 2022YFE03050003)National Natural Science Foundation of China(Nos.12075284,12075283 and 12175277)。
文摘In the H-mode experiments conducted on the Experimental Advanced Superconducting Tokamak(EAST),fluctuations induced by the so-called edge localized modes(ELMs)are captured by a high-speed vacuum ultraviolet(VUV)imaging system.Clear field line-aligned filamentary structures are analyzed in this work.Ion transport induced by ELM filaments in the scrape-off layer(SOL)under different discharge conditions is analyzed by comparing the VUV signals with the divertor probe signals.It is found that convective transport along open field lines towards the divertor target dominates the parallel ion particle transport mechanism during ELMs.The toroidal mode number of the filamentary structure derived from the VUV images increases with the electron density pedestal height.The analysis of the toroidal distribution characteristics during ELM bursts reveals toroidal asymmetry.The influence of resonance magnetic perturbation(RMP)on the ELM size is also analyzed using VUV imaging data.When the phase difference of the coil changes periodically,the widths of the filaments change as well.Additionally,the temporal evolution of the ELMs on the VUV signals provides rise time and decay time for each single ELM event,and the results indicate a negative correlation trend between these two times.
基金supported by the National Magnetic Confinement Fusion Energy R & D Program of China (No. 2018 YFE0309101)National Natural Science Foundation of China (Nos. 12305243 and 51821005)。
文摘Three-dimensional(3D) equilibrium calculations, including the plasma rotation shielding effect to resonant magnetic perturbations(RMPs) produced by the island divertor(ID) coils, were carried out using the HINT and MARS-F codes on J-TEXT. Validation of 3D equilibrium calculations with experimental observations demonstrates that the shielding effect will prevent the penetration of the edge m/n = 3/1 mode component when the ID coil current is 4 k A, while change the size of magnetic islands once the current exceeds the penetration threshold. This indicates that equilibrium calculations including the plasma rotation shielding effect to RMPs can lead to better agreements with experimental observations compared to the vacuum approximation method. Additionally, the magnetic topology at the boundary undergoes changes,impacting the interaction between the plasma and the target plate. These results may be important in understanding RMP effects on edge transport and magnetohydrodynamic(MHD)instability control, as well as divertor heat and particle flux distribution control.
基金Korea Institute of Industrial Technology,Grant/Award Number:KITECH EO‐22‐0005National Research Foundation of Korea,Grant/Award Numbers:2022R1A3B1078163,2022R1A4A1031182,2022R1A2C2005701。
文摘Herein,a layer of molybdenum oxide(MoO_(x)),a transition metal oxide(TMO),which has outstanding catalytic properties in combination with a carbonbased thin film,is modified to improve the hydrogen production performance and protect the MoO_(x)in acidic media.A thin film of graphene is transferred onto the MoO_(x)layer,after which the graphene structure is doped with N and S atoms at room temperature using a plasma doping method to modify the electronic structure and intrinsic properties of the material.The oxygen functional groups in graphene increase the interfacial interactions and electrical contacts between graphene and MoO_(x).The appearance of surface defects such as oxygen vacancies can result in vacancies in MoO_(x).This improves the electrical conductivity and electrochemically accessible surface area.Increasing the number of defects in graphene by adding dopants can significantly affect the chemical reaction at the interfaces and improve the electrochemical performance.These defects in graphene play a crucial role in the adsorption of H^(+)ions on the graphene surface and their transport to the MoO_(x)layer underneath.This enables MoO_(x)to participate in the reaction with the doped graphene.N^(‐)and S^(‐)doped graphene(NSGr)on MoO_(x)is active in acidic media and performs well in terms of hydrogen production.The initial overpotential value of 359 mV for the current density of−10 mA/cm^(2)is lowered to 228 mV after activation.
文摘This paper proposes a parameter determination method of distribution voltage regulators load ratio control transformers （LRT） and step voltage regulators （SVR） considering the tap change and voltage profile. The method takes two procedures in order to simplify the optimization problem and to reduce calculation time. One is to simultaneously determine the control parameters of LRT and SVR minimizing voltage violations and voltage variations. The algorithm is based on particle swarm optimization （PSO）, which is one of non-linear optimization methods by using a concept of swarm intelligence. Another is to determine the dead-band width of LRT and SVR on the basis of bi-evaluation of tap change and voltage margin. The concept of a Pareto optimal solution is used for the decision of the best dead-band width. As the results of numerical simulations using distribution network model, the validity of the proposed method has been affirmed.
