The advent of large language models(LLMs)has made knowledge acquisition and content creation increasingly easier and cheaper,which in turn redefines learning and urges transformation in software engineering education....The advent of large language models(LLMs)has made knowledge acquisition and content creation increasingly easier and cheaper,which in turn redefines learning and urges transformation in software engineering education.To do so,there is a need to understand the impact of LLMs on software engineering education.In this paper,we conducted a preliminary case study on three software requirements engineering classes where students are allowed to use LLMs to assist in their projects.Based on the students’experience,performance,and feedback from a survey conducted at the end of the courses,we characterized the challenges and benefits of applying LLMs in software engineering education.This research contributes to the ongoing discourse on the integration of LLMs in education,emphasizing both their prominent potential and the need for balanced,mindful usage.展开更多
This study explores engineering risk prevention and control in electromechanical engineering from the technical management perspective.It elaborates on technical management’s role,core concepts,critical risks,and var...This study explores engineering risk prevention and control in electromechanical engineering from the technical management perspective.It elaborates on technical management’s role,core concepts,critical risks,and various strategies like fail-safe design,predictive maintenance,ISO-compliant workflows.It also emphasizes future research areas such as AI-driven predictive risk modeling and cross-disciplinary management frameworks.展开更多
Employee turnover presents considerable challenges for organizations,leading to increased recruitment costs and disruptions in ongoing operations.High voluntary attrition rates can result in substantial financial loss...Employee turnover presents considerable challenges for organizations,leading to increased recruitment costs and disruptions in ongoing operations.High voluntary attrition rates can result in substantial financial losses,making it essential for Human Resource(HR)departments to prioritize turnover reduction.In this context,Artificial Intelligence(AI)has emerged as a vital tool in strengthening business strategies and people management.This paper incorporates two new representative features,introducing three types of feature engineering to enhance the analysis of employee turnover in the IBM HR Analytics dataset.Key Machine Learning(ML)techniques were subsequently employed in this work,such as Support Vector Machine(SVM),Random Forest(RF),Logistic Regression(LR),Extreme Gradient Boosting(XGBoost),and especially Categorical Boosting(CatBoost),a gradient boosting algorithm optimized for categorical data to analyze employee turnover.Adopting the unique feature engineering process enables CatBoost to enhance model accuracy and robustness while effectively analyzing complex patterns within employee data.Experimental results demonstrate the effectiveness of our proposed methodology,achieving the highest accuracy of 90.14%and an F1-score of 0.88 on the IBM dataset.To assess the capability of our detection system,we have also used an extended dataset,achieving an optimal accuracy of 98.10%and an F1-score of 0.98.These results strongly indicate the efficiency of our proposed methodology and highlight the impact of feature engineering on predictive performance.Moreover,by pinpointing the top ten factors influencing attrition,including“Monthly Income”,“Over Time”,“Total Satisfaction”,and others,this research equips HR departments with insights to implement targeted retention strategies,such as enhancing compensation or job satisfaction,to retain key talent before they consider leaving.展开更多
China’s urbanization has entered a mid-to-late phase,and is characterized by high-density urban engineering projects that form systems coupled to geotechnical environments.These systems exhibit significant vulnerabil...China’s urbanization has entered a mid-to-late phase,and is characterized by high-density urban engineering projects that form systems coupled to geotechnical environments.These systems exhibit significant vulnerability due to strong spatiotemporal coupling,which hampers sustainable urban development.Traditional approaches to urban engineering design,construction,and maintenance tend to focus on individual projects and lack the ability to comprehensively evaluate system-level sustainability.Thus,with current methods,it is difficult to optimize the renewal and operation of high-density urban engineering systems.In this study,the constituent elements and key features of high-density urban engineering systems are discussed,and urban engineering system sustainability evaluation indicators are comprehensively reviewed.Viewed from perspectives of resilience,low-carbon development,and ecological impact,66 performance indicators describing urban engineering systems are selected.The decision-making trial and evaluation laboratory(DEMATEL)-based analytic network process(DANP)method and the entropy weight method(EWM)are utilized to calculate these indicators’subjective and objective weights,respectively.Furthermore,the coupling relationships between evaluation indicators are explored,aiding the construction of an urban engineering sustainability evaluation index system.Finally,empirical analysis is conducted across six megacities in China(Tianjin,Hangzhou,Shanghai,Wuhan,Chongqing,and Shenzhen)to validate the effectiveness of the evaluation indicators.The findings reveal significant imbalances in the sustainability of urban engineering systems in China.Accordingly,potential strategies and indicators for targeted enhancement of these systems are discussed.展开更多
In recent years, transition metal phosphorus trichalcogenides MPX_(3)(M = transition metal, X = S, Se) have garnered significant attention in the field of two-dimensional van der Waals materials on account of their un...In recent years, transition metal phosphorus trichalcogenides MPX_(3)(M = transition metal, X = S, Se) have garnered significant attention in the field of two-dimensional van der Waals materials on account of their unique layered structures and diverse physical properties. In this work, we systematically investigated the vibrational modes and band gap evolution of ZnPSe_(3) under extreme conditions using Raman spectroscopy and high-pressure ultraviolet–visible(UV-vis) absorption spectroscopy. The experimental results demonstrate that the vibrational modes of ZnPSe_(3) remain stable at low temperatures(5–300 K) and high pressures(0–22.1 GPa). Notably, the band gap of ZnPSe_(3) exhibits an initial increase followed by a decrease under pressures ranging from 0 to 20.6 GPa, which is likely associated with a pressure-induced transition from an indirect to a direct band gap. This work not only enriches the understanding of van der Waals materials but also provides crucial experimental insights for their application in band gap engineering.展开更多
Formamidinium lead bromide(FAPbBr_(3))perovskite nanocrystals(NCs)are promising for display and lighting due to their ultra-pure green emission.However,the thermal quenching will exacerbate their performance degradati...Formamidinium lead bromide(FAPbBr_(3))perovskite nanocrystals(NCs)are promising for display and lighting due to their ultra-pure green emission.However,the thermal quenching will exacerbate their performance degradation in practical applications,which is a common issue for halide perovskites.Here,we reported the heat-resistant FAPbBr_(3)NCs prepared by a ligand-engineered room-temperature synthesis strategy.An aromatic amine,specificallyβ-phenylethylamine(PEA)or 3-fluorophenylethylamine(3-F-PEA),was incoporated as the short-chain ligand to expedite the crystallization rate and control the size distribution of FAPbBr_(3)NCs.Employing this ligand engineering approach,we synthesized high quality FAPbBr_(3)NCs with uniform grain size and reduced long-chain alkyl ligands,resulting in substantially suppressed thermal quenching and enhanced carrier transportation in the perovskite NCs films.Most notably,more than 90%of the room temperature PL intensity in the 3-F-PEA modified FAPbBr_(3)NCs film was preserved at 380 K.Consequently,we fabricated ultra-pure green EL devices with a room temperature external quantum efficiency(EQE)as high as 21.9%at the luminance of above 1,000 cd m^(-2),and demonstrated less than 10%loss in EQE at 343 K.This study introduces a novel room temperature method to synthesize efficient FAPbBr_(3)NCs with exceptional thermal stability,paving the way for advanced optoelectronic device applications.展开更多
Mine water pollution caused by improper discharge of industrial wastewater,waste liquid and waste residue into minedout areas is a new form of pollution occurred in China in recent years.This kind of pollution is buri...Mine water pollution caused by improper discharge of industrial wastewater,waste liquid and waste residue into minedout areas is a new form of pollution occurred in China in recent years.This kind of pollution is buried deeply,and it is difficult to control,dispose and repair.Deep contaminated mine water from abandoned mining areas may even enter the ocean,posing a great threat to marine ecosystems.In this study,using a water pollution incident occurred in a coal field at a depth of 80 m in Shandong Province,China,in 2015,as an example,the methods of engineering block disposal and groundwater remediation are reported,and the remediation effects are tested and evaluated by in-situ chemical detection and geophysical surveys.The test results showed that engineering blocking measures such as cut-off walls can obviously block the DNAPL diffusion process in mine water,but the blocking effect on organic pollutants dissolved in water was limited.It can slow down the diffusion process of organic gas.The presence of mining tunnels and mined-out areas in the contaminated zone enhances the diffusion speed of various pollutants,especially during the remediation process when pollutants rapidly spread throughout the entire contaminated area.Groundwater circulation extraction and oxidation methods have a significant degradation effect on pollutants like dichloromethane,but they may generate a large amount of secondary gaseous pollutants.These gaseous pollutants may migrate to the shallow subsurface through structures such as faults,leading to secondary subsurface contamination.When designing remediation plans,it is crucial to strike a balance between blocking and guiding in the context of both blocking and restoration projects for achieving effective remediation.展开更多
Expanding the specific surface area of substrates and carrying out precise surface engineering of imprinted nanocavities are crucial methods for enhancing the identification efficiency of molecularly imprinted polymer...Expanding the specific surface area of substrates and carrying out precise surface engineering of imprinted nanocavities are crucial methods for enhancing the identification efficiency of molecularly imprinted polymers(MIPs).To implement this synergistic strategy,bioinspired surface engineering was used to incorporate dual covalent receptors via precise post-imprinting modifications(PIMs)onto mesoporous silica nanosheets.The prepared sorbents(denoted as‘‘D-PMIPs”)were utilized to improve the specific identification of adenosine 5-monophosphate(AMP).Significantly,the mesoporous silica nanosheets possess a high surface area of approximately 498.73 m^(2)·g^(-1),which facilitates the formation of abundant specific recognition sites in the D-PMIPs.The dual covalent receptors are valuable for estab-lishing the spatial orientation and arrangement of AMP through multiple cooperative interactions.PIMs enable precise site-specific functionalization within the imprinted cavities,leading to the tailor-made formation of complementary binding sites.The maximum number of high-affinity binding sites(Nmax)of the D-PMIPs is 39.99 lmol·g^(-1),which is significantly higher than that of imprinted sorbents with a sin-gle receptor(i.e.,S-BMIPs or S-PMIPs).The kinetic data of the D-PMIPs can be effectively described by a pseudo-second-order model,indicating that the main binding mechanism involves synergistic chemisorption from boronate affinity and the pyrimidine base.This study suggests that using dual cova-lent receptors and PIMs is a reliable approach for creating imprinted sorbents with high selectivity,allow-ing for the controlled engineering of imprinted sites.展开更多
Casing deformation is a widespread problem in a certain block of Jiaoshiba Shale Gas Field in Sichuan Basin,China,and it severely limits the development benefits of shale gas in that block.Based on the spatiotemporal ...Casing deformation is a widespread problem in a certain block of Jiaoshiba Shale Gas Field in Sichuan Basin,China,and it severely limits the development benefits of shale gas in that block.Based on the spatiotemporal characteristics of block formation,fracture development,and casing deformation occurrence,this paper employs an integrated geological—engineering research approach to identify the primary mechanisms governing casing deformation within the block and proposes countermeasures to prevent such deformation.The present research indicates the following findings:(1)The block has undergone multiple phases of tectonic superposition,with fracture development serving as the geological factor causing casing deformation.(2)Fracturing activation constitutes the engineering factor causing casing deformation,with 4 mm of formation slip inducing deformation.(3)The fracture activation risk map shows that Class Ⅰ and Class Ⅱ fractures account for 73.36%of the total recorded in the block.Within the most susceptible Class I risk zone,the critical activation pressure increment for fracturing operations ranges from 13.43 MPa to 13.99 MPa.Based on the distribution of casing failure risk zones identified in the fracture activation risk map,this paper proposes relevant technical countermeasures for preventing casing failure from three perspectives:shale gas well location deployment,drilling techniques,and fracturing techniques.These measures provide robust support for safeguarding the integrity of casing systems within the studied block.展开更多
The ocean holds abundant petroleum,natural gas,and mineral resources that form an essential material foundation for the sustainable development of modern society.The safe and efficient exploitation of these resources ...The ocean holds abundant petroleum,natural gas,and mineral resources that form an essential material foundation for the sustainable development of modern society.The safe and efficient exploitation of these resources depends heavily on various slender,composite,flexible structures,including umbilical cables,dynamic power cables for offshore wind turbines,petroleum pipelines(both bonded and unbonded),deep-sea mining risers,and LNG cryogenic flexible hoses.These structures feature highly complex configurations and incur substantial design and manufacturing costs,while operating in environments far more severe and variable than those of onshore pipelines.They must withstand multisource stochastic loads generated by the combined action of wind,waves,currents,and tides,and maintain robustness under extreme conditions such as typhoons,earthquakes,and explosions.展开更多
Electrocatalytic nitric oxide(NO)reduction reaction(NORR)is a promising and sustainable process that can simultaneously realize green ammonia(NH3)synthesis and hazardous NO removal.However,current NORR performances ar...Electrocatalytic nitric oxide(NO)reduction reaction(NORR)is a promising and sustainable process that can simultaneously realize green ammonia(NH3)synthesis and hazardous NO removal.However,current NORR performances are far from practical needs due to the lack of efficient electrocatalysts.Engineering the lattice of metal-based nanomaterials via phase control has emerged as an effective strategy to modulate their intrinsic electrocatalytic properties.Herein,we realize boron(B)-insertion-induced phase regulation of rhodium(Rh)nanocrystals to obtain amorphous Rh_(4)B nanoparticles(NPs)and hexagonal close-packed(hcp)RhB NPs through a facile wet-chemical method.A high Faradaic efficiency(92.1±1.2%)and NH_(3) yield rate(629.5±11.0μmol h^(−1) cm^(−2))are achieved over hcp RhB NPs,far superior to those of most reported NORR nanocatalysts.In situ spectro-electrochemical analysis and density functional theory simulations reveal that the excellent electrocatalytic performances of hcp RhB NPs are attributed to the upshift of d-band center,enhanced NO adsorption/activation profile,and greatly reduced energy barrier of the rate-determining step.A demonstrative Zn-NO battery is assembled using hcp RhB NPs as the cathode and delivers a peak power density of 4.33 mW cm−2,realizing simultaneous NO removal,NH3 synthesis,and electricity output.展开更多
1.Introduction The precipitation of κ-carbides is critical for the deformation behavior of Fe-Mn-Al-C austenitic low-density steels[1-5].Ther-momechanical treatment can significantly influence the distribution,size,a...1.Introduction The precipitation of κ-carbides is critical for the deformation behavior of Fe-Mn-Al-C austenitic low-density steels[1-5].Ther-momechanical treatment can significantly influence the distribution,size,and morphology of κ-carbides,and thus regulate the mechanical properties[1,4,6-8].Intragranular κ-carbides precipitate through either nucleation and growth mechanisms[9]or spinodal decomposition[3,5],depending on thermodynamic conditions.展开更多
High-performance alloys are indispensable in modern engineering because of their exceptional strength,ductility,corrosion resistance,fatigue resistance,and thermal stability,which are all significantly influenced by t...High-performance alloys are indispensable in modern engineering because of their exceptional strength,ductility,corrosion resistance,fatigue resistance,and thermal stability,which are all significantly influenced by the alloy interface structures.Despite substantial efforts,a comprehensive overview of interface engineering of high-performance alloys has not been presented so far.In this study,the interfaces in high-performance alloys,particularly grain and phase boundaries,were systematically examined,with emphasis on their crystallographic characteristics and chemical element segregations.The effects of the interfaces on the electrical conductivity,mechanical strength,toughness,hydrogen embrittlement resistance,and thermal stability of the alloys were elucidated.Moreover,correlations among various types of interfaces and advanced experimental and computational techniques were examined using big data analytics,enabling robust design strategies.Challenges currently faced in the field of interface engineering and emerging opportunities in the field are also discussed.The study results would guide the development of next-generation high-performance alloys.展开更多
To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt b...To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt by physical property index,microscopic morphology,rheological testing,and infrared spectroscopy on multiple scales.The results show that the best preparation process for TB-modified asphalt is stirring at 260℃ for 4 h at 400 rpm,which significantly reduces the modification time of the asphalt.From a physical property viewpoint,the TB composite-modified asphalt sample with 5% styrene-butadiene-styrene(SBS)+1% aromatics+0.1% sulfur exhibits high-comprehensive,high-and low-temperature properties.More-over,its crosslinked mesh structure comprises black rubber particles uniformly interwoven in the middle,which further enhances the performance of the asphalt and results in an excellent performance formulation.In addition,the sample with 5%SBS content has a higher G*value and smaller δ value than that with 3%SBS content,indicating that its high-temperature resistance is improved.The effect of adding 3%SBS content on the viscoelastic ratio is,to some extent,less than that caused by 20% rubber powder.展开更多
The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytot...The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytotoxicity.These limitations have catalyzed the development of intelligent stimuli-responsive block copolymers-based bioimaging agents,which was engineered to dynamically respond to endogenous biochemical cues(e.g.,p H gradients,redox potential,enzyme activity,hypoxia environment) or exogenous physical triggers(e.g.,photoirradiation,thermal gradients,ultrasound(US)/magnetic stimuli).Through spatiotemporally controlled structural transformations,stimuli-responsive block copolymers enable precise contrast targeting,activatable signal amplification,and theranostic integration,thereby substantially enhancing signal-to-noise ratios of bioimaging and diagnostic specificity.Hence,this mini-review systematically examines molecular engineering principles for designing p H-,redox-,enzyme-,light-,thermo-,and US/magnetic-responsive polymers,with emphasis on structure-property relationships governing imaging performance modulation.Furthermore,we critically analyze emerging strategies for optical imaging,US synergies,and magnetic resonance imaging(MRI).Multimodal bioimaging has also been elaborated,which could overcome the inherent trade-offs between resolution,penetration depth,and functional specificity in single-modal approaches.By elucidating mechanistic insights and translational challenges,this mini-review aims to establish a design framework of stimuli-responsive block copolymersbased for high fidelity bioimaging agents and accelerate their clinical translation in precise diagnosis and therapy.展开更多
In the field of organic solar cells(OSCs),side-chain engineering is a key strategy for developing high-performance non-fullerene small molecule acceptors(SMAs),which could adjust the material solubility and modulate t...In the field of organic solar cells(OSCs),side-chain engineering is a key strategy for developing high-performance non-fullerene small molecule acceptors(SMAs),which could adjust the material solubility and modulate the intermolecular stacking properties,profoundly impacting the film morphology and thus acting on the final power conversion efficiency(PCE) of the materials.In this study,two asymmetric acceptor molecules,Qx-Ph Br-BO and Qx-Ph Br-X,were synthesized by migrating the branching site of the outer side chain from the β-site to the γ-site.The branching site located at the γ-site could reduce the steric-hindrance effect and enhance the molecular aggregation behavior,giving rise to redshifted absorption and tight π-π stacking.Morphology analysis shows that the Qx-Ph Br-X-based devices have smoother surfaces and a phase-separated structure,which is more favorable for charge transport and extraction.The Qx-Ph Br-X-based devices exhibit balanced hole-electron mobility,efficient exciton dissociation,and low charge recombination.As a result,Qx-Ph Br-X with γ-site branching exhibits superior photovoltaic performance with a PCE of 17.16 %,which is significantly higher than that of Qx-Ph Br-BO at 16.28 %.These results highlight the importance of side-chain modifications for optimizing OSC efficiency and provide an important reference for precise tuning of side-chain structures in future molecular design.展开更多
Quantum dot systems emerge as promising platforms for studying nanoscale thermoelectric effects and quantum fluctuation phenomena.In this work,we investigate the thermodynamic performance of a Coulomb-blockaded quantu...Quantum dot systems emerge as promising platforms for studying nanoscale thermoelectric effects and quantum fluctuation phenomena.In this work,we investigate the thermodynamic performance of a Coulomb-blockaded quantum dot operating as a quantum heat engine using the quantum master equation approach.By incorporating full counting statistics,we analyze both average transport properties and current fluctuations in this nanoscale system.We demonstrate that electron-electron interactions significantly enhance thermoelectric performance by increasing both the output power and energy conversion efficiency.Furthermore,we show that Coulomb interactions suppress current fluctuations while preserving the validity of the thermodynamic uncertainty relation.Our results provide important insights into the interplay between quantum effects and thermodynamic principles in nanoscale heat engines.展开更多
Layered oxides have attracted significant attention as cathodes for sodium-ion batteries(SIBs)due to their compositional versatility and tuneable electrochemical performance.However,these materials still face challeng...Layered oxides have attracted significant attention as cathodes for sodium-ion batteries(SIBs)due to their compositional versatility and tuneable electrochemical performance.However,these materials still face challenges such as structural phase transitions,Na^(+)/vacancy ordering,and Jahn–Teller distortion effect,resulting in severe capacity decay and sluggish ion kinetics.We develop a novel Cu/Y dual-doping strategy that leads to the formation of"Na–Y"interlayer aggregates,which act as structural pillars within alkali metal layers,enhancing structural stability and disrupting the ordered arrangement of Na^(+)/vacancies.This disruption leads to a unique coexistence of ordered and disordered Na^(+)/vacancy states with near-zero strain,which significantly improves Na^(+)diffusion kinetics.This structural innovation not only mitigates the unfavorable P2–O2 phase transition but also facilitates rapid ion transport.As a result,the doped material demonstrates exceptional electrochemical performance,including an ultra-long cycle life of 3000 cycles at 10 C and an outstanding high-rate capability of~70 mAh g^(−1)at 50 C.The discovery of this novel interlayer pillar,along with its role in modulating Na^(+)/vacancy arrangements,provides a fresh perspective on engineering layered oxides.It opens up promising new pathways for the structural design of advanced cathode materials toward efficient,stable,and high-rate SIBs.展开更多
Pre-chamber ignition technology can address the issue of uneven in-cylinder mixture combustion in large-bore marine engines.The impact of various pre-chamber structures on the formation of the mixture and jet flames w...Pre-chamber ignition technology can address the issue of uneven in-cylinder mixture combustion in large-bore marine engines.The impact of various pre-chamber structures on the formation of the mixture and jet flames within the pre-chamber is explored.This study performed numerical simulations on a large-bore marine ammonia/hydrogen pre-chamber engine prototype,considering pre-chamber volume,throat diameter,the distance between the hydrogen injector and the spark plug,and the hydrogen injector angle.Compared with the original engine,when the pre-chamber volume is 73.4 ml,the throat diameter is 14 mm,the distance ratio is 0.92,and the hydrogen injector angle is 80°.Moreover,the peak pressure in the pre-chamber increased by 23.1%,and that in the main chamber increased by 46.3%.The results indicate that the performance of the original engine is greatly enhanced by altering its fuel and pre-chamber structure.展开更多
基金supported in part by the Teaching Reform Project of Chongqing University of Posts and Telecommunications,China under Grant No.XJG23234Chongqing Municipal Higher Education Teaching Reform Research Project under Grant No.203399the Doctoral Direct Train Project of Chongqing Science and Technology Bureau under Grant No.CSTB2022BSXM-JSX0007。
文摘The advent of large language models(LLMs)has made knowledge acquisition and content creation increasingly easier and cheaper,which in turn redefines learning and urges transformation in software engineering education.To do so,there is a need to understand the impact of LLMs on software engineering education.In this paper,we conducted a preliminary case study on three software requirements engineering classes where students are allowed to use LLMs to assist in their projects.Based on the students’experience,performance,and feedback from a survey conducted at the end of the courses,we characterized the challenges and benefits of applying LLMs in software engineering education.This research contributes to the ongoing discourse on the integration of LLMs in education,emphasizing both their prominent potential and the need for balanced,mindful usage.
文摘This study explores engineering risk prevention and control in electromechanical engineering from the technical management perspective.It elaborates on technical management’s role,core concepts,critical risks,and various strategies like fail-safe design,predictive maintenance,ISO-compliant workflows.It also emphasizes future research areas such as AI-driven predictive risk modeling and cross-disciplinary management frameworks.
基金supported by Innovative Human Resource Development for Local Intellectualization program through the Institute of Information&Communications Technology Planning&Evaluation(IITP)grant funded by the Korea government(MSIT)(IITP-2024-00156287,50%)supported by Institute of Information&Communications Technology Planning&Evaluation(IITP)under the Artificial Intelligence Convergence Innovation Human Resources Development(IITP-2023-RS-2023-00256629,25%)grant funded by the Korea government(MSIT)supported by the Korea Internet&Security Agency(KISA)-Information Security College Support Project(25%).
文摘Employee turnover presents considerable challenges for organizations,leading to increased recruitment costs and disruptions in ongoing operations.High voluntary attrition rates can result in substantial financial losses,making it essential for Human Resource(HR)departments to prioritize turnover reduction.In this context,Artificial Intelligence(AI)has emerged as a vital tool in strengthening business strategies and people management.This paper incorporates two new representative features,introducing three types of feature engineering to enhance the analysis of employee turnover in the IBM HR Analytics dataset.Key Machine Learning(ML)techniques were subsequently employed in this work,such as Support Vector Machine(SVM),Random Forest(RF),Logistic Regression(LR),Extreme Gradient Boosting(XGBoost),and especially Categorical Boosting(CatBoost),a gradient boosting algorithm optimized for categorical data to analyze employee turnover.Adopting the unique feature engineering process enables CatBoost to enhance model accuracy and robustness while effectively analyzing complex patterns within employee data.Experimental results demonstrate the effectiveness of our proposed methodology,achieving the highest accuracy of 90.14%and an F1-score of 0.88 on the IBM dataset.To assess the capability of our detection system,we have also used an extended dataset,achieving an optimal accuracy of 98.10%and an F1-score of 0.98.These results strongly indicate the efficiency of our proposed methodology and highlight the impact of feature engineering on predictive performance.Moreover,by pinpointing the top ten factors influencing attrition,including“Monthly Income”,“Over Time”,“Total Satisfaction”,and others,this research equips HR departments with insights to implement targeted retention strategies,such as enhancing compensation or job satisfaction,to retain key talent before they consider leaving.
基金supported by the Fundamental Research Funds for the Central Universities(No.226-2024-00242)the Excellent Research Groups Project(No.52588202)the National Science Fund for Distinguished Young Scholars of China(No.52125803).
文摘China’s urbanization has entered a mid-to-late phase,and is characterized by high-density urban engineering projects that form systems coupled to geotechnical environments.These systems exhibit significant vulnerability due to strong spatiotemporal coupling,which hampers sustainable urban development.Traditional approaches to urban engineering design,construction,and maintenance tend to focus on individual projects and lack the ability to comprehensively evaluate system-level sustainability.Thus,with current methods,it is difficult to optimize the renewal and operation of high-density urban engineering systems.In this study,the constituent elements and key features of high-density urban engineering systems are discussed,and urban engineering system sustainability evaluation indicators are comprehensively reviewed.Viewed from perspectives of resilience,low-carbon development,and ecological impact,66 performance indicators describing urban engineering systems are selected.The decision-making trial and evaluation laboratory(DEMATEL)-based analytic network process(DANP)method and the entropy weight method(EWM)are utilized to calculate these indicators’subjective and objective weights,respectively.Furthermore,the coupling relationships between evaluation indicators are explored,aiding the construction of an urban engineering sustainability evaluation index system.Finally,empirical analysis is conducted across six megacities in China(Tianjin,Hangzhou,Shanghai,Wuhan,Chongqing,and Shenzhen)to validate the effectiveness of the evaluation indicators.The findings reveal significant imbalances in the sustainability of urban engineering systems in China.Accordingly,potential strategies and indicators for targeted enhancement of these systems are discussed.
基金Project supported by the National Key Research and Development Program of China (Grant Nos. 2021YFA1400204 and 2021YFA0718701)the National Natural Science Foundation of China (Grant Nos. 12204420, 12474021, and 12174347)。
文摘In recent years, transition metal phosphorus trichalcogenides MPX_(3)(M = transition metal, X = S, Se) have garnered significant attention in the field of two-dimensional van der Waals materials on account of their unique layered structures and diverse physical properties. In this work, we systematically investigated the vibrational modes and band gap evolution of ZnPSe_(3) under extreme conditions using Raman spectroscopy and high-pressure ultraviolet–visible(UV-vis) absorption spectroscopy. The experimental results demonstrate that the vibrational modes of ZnPSe_(3) remain stable at low temperatures(5–300 K) and high pressures(0–22.1 GPa). Notably, the band gap of ZnPSe_(3) exhibits an initial increase followed by a decrease under pressures ranging from 0 to 20.6 GPa, which is likely associated with a pressure-induced transition from an indirect to a direct band gap. This work not only enriches the understanding of van der Waals materials but also provides crucial experimental insights for their application in band gap engineering.
基金support from the National Key Research and Development Program of China(2022YFE0206000)the National Natural Science Foundation of China(U2001219,51973064)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(2023B1515040003,2024A1515010262)the Natural Science Foundation of Guangdong Province(2023B1212060003)the Open Project Program of Wuhan National Laboratory for Optoelectronics(NO.2021WNLOKF014)the State Key Lab of Luminescent Materials and Devices,South China University of Technology(Skllmd-2023-05).
文摘Formamidinium lead bromide(FAPbBr_(3))perovskite nanocrystals(NCs)are promising for display and lighting due to their ultra-pure green emission.However,the thermal quenching will exacerbate their performance degradation in practical applications,which is a common issue for halide perovskites.Here,we reported the heat-resistant FAPbBr_(3)NCs prepared by a ligand-engineered room-temperature synthesis strategy.An aromatic amine,specificallyβ-phenylethylamine(PEA)or 3-fluorophenylethylamine(3-F-PEA),was incoporated as the short-chain ligand to expedite the crystallization rate and control the size distribution of FAPbBr_(3)NCs.Employing this ligand engineering approach,we synthesized high quality FAPbBr_(3)NCs with uniform grain size and reduced long-chain alkyl ligands,resulting in substantially suppressed thermal quenching and enhanced carrier transportation in the perovskite NCs films.Most notably,more than 90%of the room temperature PL intensity in the 3-F-PEA modified FAPbBr_(3)NCs film was preserved at 380 K.Consequently,we fabricated ultra-pure green EL devices with a room temperature external quantum efficiency(EQE)as high as 21.9%at the luminance of above 1,000 cd m^(-2),and demonstrated less than 10%loss in EQE at 343 K.This study introduces a novel room temperature method to synthesize efficient FAPbBr_(3)NCs with exceptional thermal stability,paving the way for advanced optoelectronic device applications.
基金supported by the Polluted Site Remediation Project of Gao Village,Puji Street,Zhangqiu District,Jinan City,Shandong Provincefinancially supported by the National Natural Science Foundation of China(Nos.42072331,U1906209)the Taishan Scholar Foundation(No.tstp20230626)。
文摘Mine water pollution caused by improper discharge of industrial wastewater,waste liquid and waste residue into minedout areas is a new form of pollution occurred in China in recent years.This kind of pollution is buried deeply,and it is difficult to control,dispose and repair.Deep contaminated mine water from abandoned mining areas may even enter the ocean,posing a great threat to marine ecosystems.In this study,using a water pollution incident occurred in a coal field at a depth of 80 m in Shandong Province,China,in 2015,as an example,the methods of engineering block disposal and groundwater remediation are reported,and the remediation effects are tested and evaluated by in-situ chemical detection and geophysical surveys.The test results showed that engineering blocking measures such as cut-off walls can obviously block the DNAPL diffusion process in mine water,but the blocking effect on organic pollutants dissolved in water was limited.It can slow down the diffusion process of organic gas.The presence of mining tunnels and mined-out areas in the contaminated zone enhances the diffusion speed of various pollutants,especially during the remediation process when pollutants rapidly spread throughout the entire contaminated area.Groundwater circulation extraction and oxidation methods have a significant degradation effect on pollutants like dichloromethane,but they may generate a large amount of secondary gaseous pollutants.These gaseous pollutants may migrate to the shallow subsurface through structures such as faults,leading to secondary subsurface contamination.When designing remediation plans,it is crucial to strike a balance between blocking and guiding in the context of both blocking and restoration projects for achieving effective remediation.
基金supported by the National Natural Science Foundation of China(22078132,22108103,and U22A20413)the Open Funding Project of the National Key Labora-tory of Biochemical Engineering(2021KF-02)+3 种基金China Postdoctoral Science Foundation(2021M691301)Jiangsu Key Research and Development Program(BE2022356)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(CPSF)(GZ20230989)Jiangsu Agricultural Independent Innovation Fund Project(CX(21)3079).
文摘Expanding the specific surface area of substrates and carrying out precise surface engineering of imprinted nanocavities are crucial methods for enhancing the identification efficiency of molecularly imprinted polymers(MIPs).To implement this synergistic strategy,bioinspired surface engineering was used to incorporate dual covalent receptors via precise post-imprinting modifications(PIMs)onto mesoporous silica nanosheets.The prepared sorbents(denoted as‘‘D-PMIPs”)were utilized to improve the specific identification of adenosine 5-monophosphate(AMP).Significantly,the mesoporous silica nanosheets possess a high surface area of approximately 498.73 m^(2)·g^(-1),which facilitates the formation of abundant specific recognition sites in the D-PMIPs.The dual covalent receptors are valuable for estab-lishing the spatial orientation and arrangement of AMP through multiple cooperative interactions.PIMs enable precise site-specific functionalization within the imprinted cavities,leading to the tailor-made formation of complementary binding sites.The maximum number of high-affinity binding sites(Nmax)of the D-PMIPs is 39.99 lmol·g^(-1),which is significantly higher than that of imprinted sorbents with a sin-gle receptor(i.e.,S-BMIPs or S-PMIPs).The kinetic data of the D-PMIPs can be effectively described by a pseudo-second-order model,indicating that the main binding mechanism involves synergistic chemisorption from boronate affinity and the pyrimidine base.This study suggests that using dual cova-lent receptors and PIMs is a reliable approach for creating imprinted sorbents with high selectivity,allow-ing for the controlled engineering of imprinted sites.
文摘Casing deformation is a widespread problem in a certain block of Jiaoshiba Shale Gas Field in Sichuan Basin,China,and it severely limits the development benefits of shale gas in that block.Based on the spatiotemporal characteristics of block formation,fracture development,and casing deformation occurrence,this paper employs an integrated geological—engineering research approach to identify the primary mechanisms governing casing deformation within the block and proposes countermeasures to prevent such deformation.The present research indicates the following findings:(1)The block has undergone multiple phases of tectonic superposition,with fracture development serving as the geological factor causing casing deformation.(2)Fracturing activation constitutes the engineering factor causing casing deformation,with 4 mm of formation slip inducing deformation.(3)The fracture activation risk map shows that Class Ⅰ and Class Ⅱ fractures account for 73.36%of the total recorded in the block.Within the most susceptible Class I risk zone,the critical activation pressure increment for fracturing operations ranges from 13.43 MPa to 13.99 MPa.Based on the distribution of casing failure risk zones identified in the fracture activation risk map,this paper proposes relevant technical countermeasures for preventing casing failure from three perspectives:shale gas well location deployment,drilling techniques,and fracturing techniques.These measures provide robust support for safeguarding the integrity of casing systems within the studied block.
文摘The ocean holds abundant petroleum,natural gas,and mineral resources that form an essential material foundation for the sustainable development of modern society.The safe and efficient exploitation of these resources depends heavily on various slender,composite,flexible structures,including umbilical cables,dynamic power cables for offshore wind turbines,petroleum pipelines(both bonded and unbonded),deep-sea mining risers,and LNG cryogenic flexible hoses.These structures feature highly complex configurations and incur substantial design and manufacturing costs,while operating in environments far more severe and variable than those of onshore pipelines.They must withstand multisource stochastic loads generated by the combined action of wind,waves,currents,and tides,and maintain robustness under extreme conditions such as typhoons,earthquakes,and explosions.
基金funding support from General Research Fund[Project No.14300525]from the Research Grants Council(RGC)of Hong Kong SAR,Chinafunding support from Natural Science Foundation of China(NSFC)Young Scientists Fund(Project No.22305203)+2 种基金NSFC Projects Nos.22309123,22422303,22303011,22033002,92261112 and U21A20328support from the Hong Kong Branch of National Precious Metals Material Engineering Research Center(NPMM)at City University of Hong Kongsupport from Young Collaborative Research Grant[Project No.C1003-23Y]support from RGC of Hong Kong SAR,China.
文摘Electrocatalytic nitric oxide(NO)reduction reaction(NORR)is a promising and sustainable process that can simultaneously realize green ammonia(NH3)synthesis and hazardous NO removal.However,current NORR performances are far from practical needs due to the lack of efficient electrocatalysts.Engineering the lattice of metal-based nanomaterials via phase control has emerged as an effective strategy to modulate their intrinsic electrocatalytic properties.Herein,we realize boron(B)-insertion-induced phase regulation of rhodium(Rh)nanocrystals to obtain amorphous Rh_(4)B nanoparticles(NPs)and hexagonal close-packed(hcp)RhB NPs through a facile wet-chemical method.A high Faradaic efficiency(92.1±1.2%)and NH_(3) yield rate(629.5±11.0μmol h^(−1) cm^(−2))are achieved over hcp RhB NPs,far superior to those of most reported NORR nanocatalysts.In situ spectro-electrochemical analysis and density functional theory simulations reveal that the excellent electrocatalytic performances of hcp RhB NPs are attributed to the upshift of d-band center,enhanced NO adsorption/activation profile,and greatly reduced energy barrier of the rate-determining step.A demonstrative Zn-NO battery is assembled using hcp RhB NPs as the cathode and delivers a peak power density of 4.33 mW cm−2,realizing simultaneous NO removal,NH3 synthesis,and electricity output.
基金financially supported by the National Natural Science Foundation of China(grant No 52171108)the Natural Science Foundation of Liaoning Province(grant No 2023-MSBA-037)the Fundamental Research Funds for the Central University(grant No N2402007).
文摘1.Introduction The precipitation of κ-carbides is critical for the deformation behavior of Fe-Mn-Al-C austenitic low-density steels[1-5].Ther-momechanical treatment can significantly influence the distribution,size,and morphology of κ-carbides,and thus regulate the mechanical properties[1,4,6-8].Intragranular κ-carbides precipitate through either nucleation and growth mechanisms[9]or spinodal decomposition[3,5],depending on thermodynamic conditions.
基金supported by the National Natural Science Foundation of China(Nos.52122408 and 52474397)the High-level Talent Research Start-up Project Funding of Henan Academy of Sciences(No.242017127)+1 种基金the financial support from the Fundamental Research Funds for the Central Universities(University of Science and Technology Beijing(USTB),Nos.FRF-TP-2021-04C1 and 06500135)supported by USTB MatCom of Beijing Advanced Innovation Center for Materials Genome Engineering。
文摘High-performance alloys are indispensable in modern engineering because of their exceptional strength,ductility,corrosion resistance,fatigue resistance,and thermal stability,which are all significantly influenced by the alloy interface structures.Despite substantial efforts,a comprehensive overview of interface engineering of high-performance alloys has not been presented so far.In this study,the interfaces in high-performance alloys,particularly grain and phase boundaries,were systematically examined,with emphasis on their crystallographic characteristics and chemical element segregations.The effects of the interfaces on the electrical conductivity,mechanical strength,toughness,hydrogen embrittlement resistance,and thermal stability of the alloys were elucidated.Moreover,correlations among various types of interfaces and advanced experimental and computational techniques were examined using big data analytics,enabling robust design strategies.Challenges currently faced in the field of interface engineering and emerging opportunities in the field are also discussed.The study results would guide the development of next-generation high-performance alloys.
基金Funded by the National Natural Science Foundation of China(No.52278446)。
文摘To explore the best preparation process for terminal blend(TB)composite-modified asphalt and to filter its formulation with excellent performance,this study evaluates the performance of TB composite modified asphalt by physical property index,microscopic morphology,rheological testing,and infrared spectroscopy on multiple scales.The results show that the best preparation process for TB-modified asphalt is stirring at 260℃ for 4 h at 400 rpm,which significantly reduces the modification time of the asphalt.From a physical property viewpoint,the TB composite-modified asphalt sample with 5% styrene-butadiene-styrene(SBS)+1% aromatics+0.1% sulfur exhibits high-comprehensive,high-and low-temperature properties.More-over,its crosslinked mesh structure comprises black rubber particles uniformly interwoven in the middle,which further enhances the performance of the asphalt and results in an excellent performance formulation.In addition,the sample with 5%SBS content has a higher G*value and smaller δ value than that with 3%SBS content,indicating that its high-temperature resistance is improved.The effect of adding 3%SBS content on the viscoelastic ratio is,to some extent,less than that caused by 20% rubber powder.
基金supported by the National Natural Science Foundation of China (Nos.22208218,22078196,and 22278268)the Natural Science Foundation of Shanghai (No.22ZR1460400)Collaborative Innovation Center of Fragrance Flavour and Cosmetics,and Collaborative Innovation Project of Shanghai Institute of Technology (No.XTCX2023-07)。
文摘The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytotoxicity.These limitations have catalyzed the development of intelligent stimuli-responsive block copolymers-based bioimaging agents,which was engineered to dynamically respond to endogenous biochemical cues(e.g.,p H gradients,redox potential,enzyme activity,hypoxia environment) or exogenous physical triggers(e.g.,photoirradiation,thermal gradients,ultrasound(US)/magnetic stimuli).Through spatiotemporally controlled structural transformations,stimuli-responsive block copolymers enable precise contrast targeting,activatable signal amplification,and theranostic integration,thereby substantially enhancing signal-to-noise ratios of bioimaging and diagnostic specificity.Hence,this mini-review systematically examines molecular engineering principles for designing p H-,redox-,enzyme-,light-,thermo-,and US/magnetic-responsive polymers,with emphasis on structure-property relationships governing imaging performance modulation.Furthermore,we critically analyze emerging strategies for optical imaging,US synergies,and magnetic resonance imaging(MRI).Multimodal bioimaging has also been elaborated,which could overcome the inherent trade-offs between resolution,penetration depth,and functional specificity in single-modal approaches.By elucidating mechanistic insights and translational challenges,this mini-review aims to establish a design framework of stimuli-responsive block copolymersbased for high fidelity bioimaging agents and accelerate their clinical translation in precise diagnosis and therapy.
基金the financial support by the Beijing Natural Science Foundation (No.Z230018)the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB0520102)CAS Project for Young Scientists in Basic Research (No.YSBR-102)。
文摘In the field of organic solar cells(OSCs),side-chain engineering is a key strategy for developing high-performance non-fullerene small molecule acceptors(SMAs),which could adjust the material solubility and modulate the intermolecular stacking properties,profoundly impacting the film morphology and thus acting on the final power conversion efficiency(PCE) of the materials.In this study,two asymmetric acceptor molecules,Qx-Ph Br-BO and Qx-Ph Br-X,were synthesized by migrating the branching site of the outer side chain from the β-site to the γ-site.The branching site located at the γ-site could reduce the steric-hindrance effect and enhance the molecular aggregation behavior,giving rise to redshifted absorption and tight π-π stacking.Morphology analysis shows that the Qx-Ph Br-X-based devices have smoother surfaces and a phase-separated structure,which is more favorable for charge transport and extraction.The Qx-Ph Br-X-based devices exhibit balanced hole-electron mobility,efficient exciton dissociation,and low charge recombination.As a result,Qx-Ph Br-X with γ-site branching exhibits superior photovoltaic performance with a PCE of 17.16 %,which is significantly higher than that of Qx-Ph Br-BO at 16.28 %.These results highlight the importance of side-chain modifications for optimizing OSC efficiency and provide an important reference for precise tuning of side-chain structures in future molecular design.
基金supported by the National Natural Science Foundation of China(Grant No.12305050)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(Grant No.23KJB140017)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LZ25A050001)。
文摘Quantum dot systems emerge as promising platforms for studying nanoscale thermoelectric effects and quantum fluctuation phenomena.In this work,we investigate the thermodynamic performance of a Coulomb-blockaded quantum dot operating as a quantum heat engine using the quantum master equation approach.By incorporating full counting statistics,we analyze both average transport properties and current fluctuations in this nanoscale system.We demonstrate that electron-electron interactions significantly enhance thermoelectric performance by increasing both the output power and energy conversion efficiency.Furthermore,we show that Coulomb interactions suppress current fluctuations while preserving the validity of the thermodynamic uncertainty relation.Our results provide important insights into the interplay between quantum effects and thermodynamic principles in nanoscale heat engines.
基金supported by the“Pioneer”and“Leading Goose”R&D Program of Zhejiang Province of China(No.2024C01056)。
文摘Layered oxides have attracted significant attention as cathodes for sodium-ion batteries(SIBs)due to their compositional versatility and tuneable electrochemical performance.However,these materials still face challenges such as structural phase transitions,Na^(+)/vacancy ordering,and Jahn–Teller distortion effect,resulting in severe capacity decay and sluggish ion kinetics.We develop a novel Cu/Y dual-doping strategy that leads to the formation of"Na–Y"interlayer aggregates,which act as structural pillars within alkali metal layers,enhancing structural stability and disrupting the ordered arrangement of Na^(+)/vacancies.This disruption leads to a unique coexistence of ordered and disordered Na^(+)/vacancy states with near-zero strain,which significantly improves Na^(+)diffusion kinetics.This structural innovation not only mitigates the unfavorable P2–O2 phase transition but also facilitates rapid ion transport.As a result,the doped material demonstrates exceptional electrochemical performance,including an ultra-long cycle life of 3000 cycles at 10 C and an outstanding high-rate capability of~70 mAh g^(−1)at 50 C.The discovery of this novel interlayer pillar,along with its role in modulating Na^(+)/vacancy arrangements,provides a fresh perspective on engineering layered oxides.It opens up promising new pathways for the structural design of advanced cathode materials toward efficient,stable,and high-rate SIBs.
基金Supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions under Grant No.014000319/2018-00391.
文摘Pre-chamber ignition technology can address the issue of uneven in-cylinder mixture combustion in large-bore marine engines.The impact of various pre-chamber structures on the formation of the mixture and jet flames within the pre-chamber is explored.This study performed numerical simulations on a large-bore marine ammonia/hydrogen pre-chamber engine prototype,considering pre-chamber volume,throat diameter,the distance between the hydrogen injector and the spark plug,and the hydrogen injector angle.Compared with the original engine,when the pre-chamber volume is 73.4 ml,the throat diameter is 14 mm,the distance ratio is 0.92,and the hydrogen injector angle is 80°.Moreover,the peak pressure in the pre-chamber increased by 23.1%,and that in the main chamber increased by 46.3%.The results indicate that the performance of the original engine is greatly enhanced by altering its fuel and pre-chamber structure.
