Despite the geographical distance between China and Africa,the rich customs and lifestyles of the African people present an interesting area of study for international professionals.It is this facet of Africa that fas...Despite the geographical distance between China and Africa,the rich customs and lifestyles of the African people present an interesting area of study for international professionals.It is this facet of Africa that fascinated us most during our research journey across the continent.展开更多
Urban green spaces have positive effects on both physical and mental wellbeing.However,few studies have focused on the trends and thresholds of the effects of different influences on restorative benefits when viewing ...Urban green spaces have positive effects on both physical and mental wellbeing.However,few studies have focused on the trends and thresholds of the effects of different influences on restorative benefits when viewing scenes differfeaturing plant communities.We measured subjective evaluations and objective physiological data from 44 participants who viewed images of plant communities in the yellow to green hue range to compare differences in restorative benefits among plant communities at different visual distances,as well as quantifying the influencing factors involved.The following results were found:(1)Coniferous and multi-layered plant communities were found to provide greater restorative benefits,and the restorative benefits grew with increasing visual distance.(2)Shape and color characteristics were significantly correlated with restorative benefits,but the relationship is not simply linear.(3)The restorative benefits were found to be greatest when crown proportion was 61.23%,trunk proportion ranged from 4.11%to 13.70%,and the value of color index value ranged from 25.44%to 35.56%;the restorative benefits gradually increased when sky proportion exceeded 12.95%-13.19%,the fractal dimension exceeded 1.62-1.67,and hue index exceeded 91.64°-95.67°;additionally,the restorative benefits decreased when the saturation index increased.This study provides a scientific basis for the construction and improvement of plant landscapes in urban green spaces.展开更多
The development of catalysts with highly efficient oxygen evolution performance and low-Ir loading is key to scaling up the application of proton exchange membrane(PEM)water electrolysis technology.Here,an Ir-skin cat...The development of catalysts with highly efficient oxygen evolution performance and low-Ir loading is key to scaling up the application of proton exchange membrane(PEM)water electrolysis technology.Here,an Ir-skin catalyst(Ir@KM)is realized on a potassium-manganese oxide(K_(0.25)MnO_(x)(KM))using an ion-exchange method.The Ir-skin over the prepared Ir@KM has a low Ir-Ir atomic distance,endowing an energetically favorable oxide path mechanism to allow a low theoretical overpotential of 0.13 V.Ir@KM offers a low overpotential of~280 mV at a current density of 10 mA cm^(-2)and provides a high mass activity of up to 18,500 A at a cell voltage of 1.8 V in PEM,which is 17.6 times higher than that of IrO_(2),demonstrating a significant advantage in reducing the cost of the membrane electrode.The presented Ir-skin concept represents a promising strategy to fabricate low-Ir catalyst with high activity and durability for practical applications of PEM.展开更多
With the increasing complexity of logistics operations,traditional static vehicle routing models are no longer sufficient.In practice,customer demands often arise dynamically,and multi-depot systems are commonly used ...With the increasing complexity of logistics operations,traditional static vehicle routing models are no longer sufficient.In practice,customer demands often arise dynamically,and multi-depot systems are commonly used to improve efficiency.This paper first introduces a vehicle routing problem with the goal of minimizing operating costs in a multi-depot environment with dynamic demand.New customers appear in the delivery process at any time and are periodically optimized according to time slices.Then,we propose a scheduling system TS-DPU based on an improved ant colony algorithm TS-ACO to solve this problem.The classical ant colony algorithm uses spatial distance to select nodes,while TS-ACO considers the impact of both temporal and spatial distance on node selection.Meanwhile,we adopt Cordeau’s Multi-Depot Vehicle Routing Problem with Time Windows(MDVRPTW)dataset to evaluate the performance of our system.According to the experimental results,TS-ACO,which considers spatial and temporal distance,is more effective than the classical ACO,which only considers spatial distance.展开更多
At present, enhancing the digital literacy of village cadres faces practical constraints such as governance capability gaps induced by the second-level digital divide, the absence of a systematic cultivation system, i...At present, enhancing the digital literacy of village cadres faces practical constraints such as governance capability gaps induced by the second-level digital divide, the absence of a systematic cultivation system, incomplete last-kilometer implementation for translating skills into practice, and inadequate incentive mechanisms. As a novel educational form deeply integrating digital information technology with teaching and learning, distance open education provides multi-directional empowerment for enhancing village cadres digital literacy. This is achieved through open learning methods, the application of modern digital technologies, tailored learning programs, and the establishment of "overpass bridges" for translating learning outcomes into practice. Based on this, it is essential to further streamline the pathways for educating and cultivating village cadres, vigorously promote the digitalization of teaching, practice, and support services, develop systematic and localized digital education resources, and actively explore and establish a complementary credit bank system for their digital literacy cultivation.展开更多
This paper quantitatively discusses the influence of well contact on single-event transient(SET)in sub-20 nm FinFET by two-photon absorption(TPA)pulse laser.Two groups of inverter chains were designed to investigate t...This paper quantitatively discusses the influence of well contact on single-event transient(SET)in sub-20 nm FinFET by two-photon absorption(TPA)pulse laser.Two groups of inverter chains were designed to investigate the impact of well contact distance on the FinFET process.The experimental results show that the SET pulse width has a bimodal symmetric distribution,which is different from that of a bulk planar CMOS device.To investigate the detailed mechanism of the phenomenon,a high-precision FinFET TCAD model was established,in which both Id-Vd and Id-Vg errors were less than 10%compared to the SPICE model provided by the commercial process.TCAD simulation under heavy ion injection showed the mechanism of the abnormal phenomenon,where the well contact plays a major role in charge collection at the near-well contact distance,while the source plays a major role at the far distance.This phenomenon is completely different from that of planar CMOS devices.This indicates that the SET mechanism becomes more complicated during the FinFET process.Therefore,more effective SET hardening methods should be investigated for FinFET.展开更多
A comprehensive assessment of grain supply,demand,and ecosystem service flows is essential for identifying grain movement pathways,ensuring regional grain security,and guiding sustainable management strategies.However...A comprehensive assessment of grain supply,demand,and ecosystem service flows is essential for identifying grain movement pathways,ensuring regional grain security,and guiding sustainable management strategies.However,current studies primarily focus on short-term grain provision services while neglecting the spatiotemporal variations in grain flows across different scales.This gap limits the identification of dynamic matching relationships and the formulation of optimization strategies for balancing grain flows.This study examined the spatiotemporal evolution of grain supply and demand in the Beijing-Tianjin-Hebei(BTH)region from 1980 to 2020.Using the Enhanced TwoStep Floating Catchment Area method,the grain provision ecosystem service flows were quantified,the changes in supply–demand matching under different grain flow scenarios were analyzed and the optimal distance threshold for grain flows was investigated.The results revealed that grain production follows a spatial distribution pattern characterized by high levels in the southeast and low levels in the northwest.A significant mismatch exists between supply and demand,and it shows a scale effect.Deficit areas are mainly concentrated in the northwest,while surplus areas are mainly located in the central and southern regions.As the spatial scale increases,the ecosystem service supply–demand ratio(SDR)classification becomes more clustered,while it exhibits greater spatial SDR heterogeneity at smaller scales.This study examined two distinct scenarios of grain provision ecosystem service flow dynamics based on 100 and 200 km distance thresholds.The flow increased significantly,from 2.17 to 11.81million tons in the first scenario and from 2.41 to 12.37 million tons in the second scenario over nearly 40 years,forming a spatial movement pattern from the central and southern regions to the surrounding areas.Large flows were mainly concentrated in the interior of urban centers,with significant outflows between cities such as Baoding,Shijiazhuang,Xingtai,and Hengshui.At the county scale,supply–demand matching patterns remained consistent between the grain flows in the two scenarios.Notably,incorporating grain flow dynamics significantly reduced the number of grain-deficit areas compared to scenarios without grain flow.In 2020,grain-deficit counties decreased by28.79 and 37.88%,and cities by 12.50 and 25.0%under the two scenarios,respectively.Furthermore,the distance threshold for achieving optimal supply and demand matching at the county scale was longer than at the city scale in both grain flow scenarios.This study provides valuable insights into the dynamic relationships and heterogeneous patterns of grain matching,and expands the research perspective on grain and ecosystem service flows across various spatiotemporal scales.展开更多
Traditional mining in open pit mines often uses explosives,leading to environmental hazards,with flyrock being a critical issue.In detail,excess flying rock beyond the designated explosion area was identified as the p...Traditional mining in open pit mines often uses explosives,leading to environmental hazards,with flyrock being a critical issue.In detail,excess flying rock beyond the designated explosion area was identified as the primary cause of fatal and non-fatal blasting hazards in open pit mining.Therefore,the accurate and reliable prediction of flyrock becomes crucial for effectively managing and mitigating associated problems.This study used the Light Gradient Boosting Machine(LightGBM)model to predict flyrock in a lead-zinc mine,with promising results.To improve its accuracy,multi-verse optimizer(MVO)and ant lion optimizer(ALO)metaheuristic algorithms were introduced.Results showed MVO-LightGBM outperformed conventional LightGBM.Additionally,decision tree(DT),support vector machine(SVM),and classification and regression tree(CART)models were trained and compared with MVO-LightGBM.The MVO-LightGBM model excelled over DT,SVM,and CART.This study highlights MVO-LightGBM's effectiveness and potential for broader applications.Furthermore,a multiple parametric sensitivity analysis(MPSA)algorithm was employed to specify the sensitivity of parameters.MPSA results indicated that the highest and lowest sensitivities are relevant to blasted rock per hole and spacing with theγ=1752.12 andγ=49.52,respectively.展开更多
Exo-atmospheric vehicles are constrained by limited maneuverability,which leads to the contradiction between evasive maneuver and precision strike.To address the problem of Integrated Evasion and Impact(IEI)decision u...Exo-atmospheric vehicles are constrained by limited maneuverability,which leads to the contradiction between evasive maneuver and precision strike.To address the problem of Integrated Evasion and Impact(IEI)decision under multi-constraint conditions,a hierarchical intelligent decision-making method based on Deep Reinforcement Learning(DRL)was proposed.First,an intelligent decision-making framework of“DRL evasion decision”+“impact prediction guidance decision”was established:it takes the impact point deviation correction ability as the constraint and the maximum miss distance as the objective,and effectively solves the problem of poor decisionmaking effect caused by the large IEI decision space.Second,to solve the sparse reward problem faced by evasion decision-making,a hierarchical decision-making method consisting of maneuver timing decision and maneuver duration decision was proposed,and the corresponding Markov Decision Process(MDP)was designed.A detailed simulation experiment was designed to analyze the advantages and computational complexity of the proposed method.Simulation results show that the proposed model has good performance and low computational resource requirement.The minimum miss distance is 21.3 m under the condition of guaranteeing the impact point accuracy,and the single decision-making time is 4.086 ms on an STM32F407 single-chip microcomputer,which has engineering application value.展开更多
Accurate predictions of the Remaining useful life(RUL)of mechanical equipment are vital for lowering maintenance costs and maintaining equipment reliability and safety.Datadriven RUL prediction methods have made signi...Accurate predictions of the Remaining useful life(RUL)of mechanical equipment are vital for lowering maintenance costs and maintaining equipment reliability and safety.Datadriven RUL prediction methods have made significant progress,but they often assume that the training and testing data have the same distribution,which is often not the case in practical engineering applications.To address this issue,this paper proposes a residual useful life prediction model that combines deep learning and transfer learning.In this model,called transfer convolutional attention mechanism for early-life stage time convolutional network(TCAM-EASTCN),an unsupervised domain adaptation strategy is introduced based on the characterization of subspace distances and orthogonal basis mismatch penalties in the convolutional attention mechanism for early-life stage time convolutional network(CAMEASTCN).This approach minimizes the distribution differences between different domains,enhancing the learning of cross-domain invariant features and effectively reducing the distribution gap between the source and target domains,thereby improving the accuracy of RUL prediction under varying conditions.Experimental results demonstrate that TCAMEASTCN outperforms other models in terms of RUL prediction accuracy and generalization.展开更多
The purpose of this article is to introduce a new method with a self-adaptive stepsize for approximating a common solution of monotone inclusion problems and variational inequality problems in reflexive Banach spaces....The purpose of this article is to introduce a new method with a self-adaptive stepsize for approximating a common solution of monotone inclusion problems and variational inequality problems in reflexive Banach spaces.The strong convergence result for our method is established under some standard assumptions without any requirement of the knowledge of the Lipschitz constant of the mapping.Several numerical experiments are provided to verify the advantages and efficiency of proposed algorithms.展开更多
K-means uses the sum-of-squared error as the objective function to minimize within-cluster distances.We show that,as a consequence,it also maximizes between-cluster variances.This means that the two measures do not pr...K-means uses the sum-of-squared error as the objective function to minimize within-cluster distances.We show that,as a consequence,it also maximizes between-cluster variances.This means that the two measures do not provide complementary information and that using only one is enough.Based on this property,we propose a new objective function called cluster overlap,which is measured intuitively as the proportion of points shared between the clusters.We adopt the new function within k-means and present an algorithm called overlap k-means.It is an alternative way to design a k-means algorithm.A localized variant is also provided by limiting the overlap calculation to the neighboring points.展开更多
1.The price of a desk is 10 times the price of a chair.The desk costs 288 yuan more than the chair.How much does one desk and one chair cost?2.A and B start from two different places and walk toward each other.After 4...1.The price of a desk is 10 times the price of a chair.The desk costs 288 yuan more than the chair.How much does one desk and one chair cost?2.A and B start from two different places and walk toward each other.After 4 hours,they meet at a point that is 4 kilometres away from the midpoint between their starting points.A walks faster than B.How many more kilometres per hour does A walk than B?展开更多
Background:Bat ear is a congenital condition that can have psychological effects on patients and is readily correctable,often yielding highly satisfactory outcomes for both patients and surgeons.It is crucial to selec...Background:Bat ear is a congenital condition that can have psychological effects on patients and is readily correctable,often yielding highly satisfactory outcomes for both patients and surgeons.It is crucial to select appropriate techniques in the surgical plan to ensure optimal outcomes.This study aimed to compare the outcomes of otoplasty using the cartilage scoring technique versus the cartilage excision technique for correcting the antihelix.Methods:Twenty patients were divided into two groups:group A underwent the cartilage scoring technique,and group B received the cartilage excision technique.Symmetry,satisfaction,and complications were evaluated and compared between the groups.A visual analog score(VAS)was used to assess the perceived symmetry and satisfaction in both groups.Results:Group A(cartilage scoring technique)demonstrated excellent postoperative symmetry,with a total symmetry score of 96/100 on cartilage grading.In group B,6 of the 10 individuals reported high satisfaction(score:10/10 points on VAS),whereas the remaining 4 reported moderate satisfaction(score:5–9/10 points).The total symmetry score in group B(cartilage excision technique)was 92/100,which was lower than that in group A.No relapses in angle measurements were observed in group A.In contrast,group B showed six average and four slightly overcorrected angle measurements.In group B,the postoperative measures were less satisfactory.Angle measurements were average angles in four cases,and somewhat overcorrected in six.Regarding the helix-to-mastoid distance,three cases were within the average range,whereas seven were slightly overcorrected.No relapses were observed in either group.Concerning complications,we employed minus scoring to measure all complications.Group A had a negative score of19,whereas group B had24.Conclusion:The outcomes were highly satisfactory for patients and surgeons treated using the cartilage scoring technique,and relatively less satisfactory for patients and surgeons treated using the cartilage excision technique.展开更多
Model calculations and laboratory experiments were conducted to investigate the influence of surface tension of the molten steel on the agglomeration trend of Al_(2)O_(3) inclusions.The agglomeration trends of inclusi...Model calculations and laboratory experiments were conducted to investigate the influence of surface tension of the molten steel on the agglomeration trend of Al_(2)O_(3) inclusions.The agglomeration trends of inclusions were compared using the calculated attractiveness.When the S content in the steel increased from 2.7×10^(-6) to 789×10^(-6),the surface tension of the molten steel decreased from 1.91 to 1.39 N/m,while the attractive force between inclusions increased from 5×10^(-18) to 5×10^(-16) N,and the critical collision distance of Al_(2)O_(3) inclusions gradually increased from 30 to 70μm.A model of the relationship between the capillary force of inclusions and S content in steel was established.It was found that the capillary force calculated by the model showed the same trend as the attractive force obtained from experiments,and an increase in the S content promoted the attraction between inclusions.展开更多
A centrifugal pump with a specific speed ns=67 is considered in this study to investigate the impact of blade cutting(at the outlet edge)on the fluid-induced noise,while keeping all the other geometric parameters unch...A centrifugal pump with a specific speed ns=67 is considered in this study to investigate the impact of blade cutting(at the outlet edge)on the fluid-induced noise,while keeping all the other geometric parameters unchanged.The required unsteady numerical calculations are conducted by applying the RNG k-εturbulence model with the volute dipole being used as the sound source.The results indicate that the internal pressure energy of the centrifugal pump essentially depends on the blade passing frequency and its low-frequency harmonic frequency.Moreover,the pressure pulsation distribution directly affects the noise caused by the centrifugal pump.The sound pressure inside and outside the centrifugal pump and the sound power at the blade passing frequency gradually decrease increasing cutting distance of the impeller blades.When the cutting percentage is 1.21%,that is,the clearance ratio between impeller blade and tongue is 8.57%,the comprehensive performance of the centrifugal pump is the best.展开更多
BACKGROUND Normothermic liver machine perfusion(NMP)is a novel technology used to preserve and evaluate the function of liver allografts.AIM To assess NMP utilization in liver transplant(LT)practices.METHODS All adult...BACKGROUND Normothermic liver machine perfusion(NMP)is a novel technology used to preserve and evaluate the function of liver allografts.AIM To assess NMP utilization in liver transplant(LT)practices.METHODS All adult deceased-donor LT recipients between January 2021 and September 2023 in the United States were analyzed.Outcomes including discard rates,survival,preservation time and timing of surgery were compared between two groups:NMP vs non-NMP.RESULTS Between 2021 and 2023,NMP was utilized in 1493(6.3%)of all LTs in the United States.Compared to non-NMP group,NMP group had lower allograft discard rate(6.5%vs 10%,P<0.001),older recipients’age(median:47 vs 42 years,P<0.001),and higher utilization of donors from donation after circulatory death(DCD)(55%vs 11%,P<0.001).NMP group also had longer distances between recipient and donor hospitals(median:156 vs 138 miles,P<0.001),longer preser-vation time(median:12.2 vs 5.8 hours,P<0.001),and more daytime reperfusion(74%vs 55%,P<0.001).Post-transplant survival outcomes were comparable between the two groups.In a subgroup analysis of NMP,recipients in the long preservation time(≥8 hours)group had higher daytime reperfusion(78%vs 55%,P<0.001)and similar post-transplant survival when compared to the short preservation time(<8 hours)group.CONCLUSION The utilization of NMP is associated with lower discard rates and increased DCD organs for LT.NMP allows for prolonging the preservation time and increased occurrence of daytime LT,without any impact on the survival outcomes.展开更多
Biodiversity has always been valued by ecology,Diversity is generally believed to lead to stability,and biodiversity is an important condition for ecosystems to maintain health.So what factors are related to forest ec...Biodiversity has always been valued by ecology,Diversity is generally believed to lead to stability,and biodiversity is an important condition for ecosystems to maintain health.So what factors are related to forest ecosystem biodiversity,and what kind of forest structure affects and determines the size of biodiversity.This study proposes the concept of contained uniformity based on the theory of uniformity,and uses the convergence of contained uniformity to obtain the judgment model of the forest station pattern type.At the same time,it proposes the concept of forest ecosystem distance diversity,and uses the judgment model of the stand pattern type to derive the mathematical definition of forest ecosystem distance diversity.Combining the ecological characteristics of different stand patterns and measurement indicators of forest ecosystem biodiversity,the connection between forest ecosystem distance diversity and biodiversity is derived,and this is used as an indicator to evaluate forest ecosystem biodiversity.Forest ecosystem distance diversity,as an indicator of biodiversity,can not only conduct early assessment and prediction of the biodiversity of immature forests(forests in the early succession or recovery stage),but also provide a quantitative basis for forest structure optimization.Ultimately realize the sustainable development of forestry production and operation and biodiversity protection.展开更多
Photometric redshifts of galaxies obtained by multi-wavelength data are widely used in photometric surveys because of their high efficiency.Although various methods have been developed,template fitting is still adopte...Photometric redshifts of galaxies obtained by multi-wavelength data are widely used in photometric surveys because of their high efficiency.Although various methods have been developed,template fitting is still adopted as one of the most popular approaches.Its accuracy strongly depends on the quality of the spectral energy distribution(SED)templates,which can be calibrated using broadband photometric data from galaxies with known spectroscopic redshifts.Such calibration is expected to improve photometric redshift accuracy,as the calibrated templates will align with observed photometric data more closely.The upcoming China Space Station Telescope(CSST)is one of the Stage IV surveys,which is aiming for high precision cosmological studies.To improve the accuracy of photometric redshift estimation for CSST,we calibrated the CWW+KIN templates using a perturbation algorithm with broadband photometric data from the CSST mock catalog.This calibration used a training set consisting of approximately 4500 galaxies,which is 10%of the total galaxy sample.The outlier fraction and scatter of the photometric redshifts derived from the calibrated templates are 2.55%and 0.036,respectively.Compared to the CWW+KIN templates,these values are reduced by 34%and 23%,respectively.This demonstrates that SED templates calibrated with a small training set can effectively optimize photometric redshift accuracy for future large-scale surveys like CSST,especially with limited spectral training data.展开更多
文摘Despite the geographical distance between China and Africa,the rich customs and lifestyles of the African people present an interesting area of study for international professionals.It is this facet of Africa that fascinated us most during our research journey across the continent.
基金funded by the National Natural Science Foundation of China(32471953)the Educational Department of Liaoning Province Key Research Project(LJ212410153073).
文摘Urban green spaces have positive effects on both physical and mental wellbeing.However,few studies have focused on the trends and thresholds of the effects of different influences on restorative benefits when viewing scenes differfeaturing plant communities.We measured subjective evaluations and objective physiological data from 44 participants who viewed images of plant communities in the yellow to green hue range to compare differences in restorative benefits among plant communities at different visual distances,as well as quantifying the influencing factors involved.The following results were found:(1)Coniferous and multi-layered plant communities were found to provide greater restorative benefits,and the restorative benefits grew with increasing visual distance.(2)Shape and color characteristics were significantly correlated with restorative benefits,but the relationship is not simply linear.(3)The restorative benefits were found to be greatest when crown proportion was 61.23%,trunk proportion ranged from 4.11%to 13.70%,and the value of color index value ranged from 25.44%to 35.56%;the restorative benefits gradually increased when sky proportion exceeded 12.95%-13.19%,the fractal dimension exceeded 1.62-1.67,and hue index exceeded 91.64°-95.67°;additionally,the restorative benefits decreased when the saturation index increased.This study provides a scientific basis for the construction and improvement of plant landscapes in urban green spaces.
基金supported by the Hainan Province Science and Technology Special Fund(ZDYF2023GXJS165)the National Natural Science Foundation of China(52164028,22109035,52274297)+2 种基金the Foundation of State Key Laboratory of Marine Resource Utilization in South China Sea(Hainan University,MRUKF2021029)the Start-up Research Foundation of Hainan University(KYQD(ZR)-20008,20084,21170)the Specific Research Fund of the Innovation Platform for Academicians of Hainan Province。
文摘The development of catalysts with highly efficient oxygen evolution performance and low-Ir loading is key to scaling up the application of proton exchange membrane(PEM)water electrolysis technology.Here,an Ir-skin catalyst(Ir@KM)is realized on a potassium-manganese oxide(K_(0.25)MnO_(x)(KM))using an ion-exchange method.The Ir-skin over the prepared Ir@KM has a low Ir-Ir atomic distance,endowing an energetically favorable oxide path mechanism to allow a low theoretical overpotential of 0.13 V.Ir@KM offers a low overpotential of~280 mV at a current density of 10 mA cm^(-2)and provides a high mass activity of up to 18,500 A at a cell voltage of 1.8 V in PEM,which is 17.6 times higher than that of IrO_(2),demonstrating a significant advantage in reducing the cost of the membrane electrode.The presented Ir-skin concept represents a promising strategy to fabricate low-Ir catalyst with high activity and durability for practical applications of PEM.
基金supported by the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology.
文摘With the increasing complexity of logistics operations,traditional static vehicle routing models are no longer sufficient.In practice,customer demands often arise dynamically,and multi-depot systems are commonly used to improve efficiency.This paper first introduces a vehicle routing problem with the goal of minimizing operating costs in a multi-depot environment with dynamic demand.New customers appear in the delivery process at any time and are periodically optimized according to time slices.Then,we propose a scheduling system TS-DPU based on an improved ant colony algorithm TS-ACO to solve this problem.The classical ant colony algorithm uses spatial distance to select nodes,while TS-ACO considers the impact of both temporal and spatial distance on node selection.Meanwhile,we adopt Cordeau’s Multi-Depot Vehicle Routing Problem with Time Windows(MDVRPTW)dataset to evaluate the performance of our system.According to the experimental results,TS-ACO,which considers spatial and temporal distance,is more effective than the classical ACO,which only considers spatial distance.
基金Supported by Science Research Fund Project of Yunnan Provincial Department of Education-Research on the Pathways for Distance Open Education to Empower the Enhancement of Digital Literacy and Skills of Rural"Leading Geese"in Ethnic Areas(2023J0792)The Ideological and Political Education Reform Project of Yunnan Province in 2022-Exploration and Practice of Integrating Ideological and Political Education into the Training Mode of"Leading Goose"Talents for Rural Revitalization in the Course of Agricultural and Forestry Economics and Management in Open Education.
文摘At present, enhancing the digital literacy of village cadres faces practical constraints such as governance capability gaps induced by the second-level digital divide, the absence of a systematic cultivation system, incomplete last-kilometer implementation for translating skills into practice, and inadequate incentive mechanisms. As a novel educational form deeply integrating digital information technology with teaching and learning, distance open education provides multi-directional empowerment for enhancing village cadres digital literacy. This is achieved through open learning methods, the application of modern digital technologies, tailored learning programs, and the establishment of "overpass bridges" for translating learning outcomes into practice. Based on this, it is essential to further streamline the pathways for educating and cultivating village cadres, vigorously promote the digitalization of teaching, practice, and support services, develop systematic and localized digital education resources, and actively explore and establish a complementary credit bank system for their digital literacy cultivation.
基金supported by Natural Science Foundation of China(Nos.62174180 and 62304258)National Key R&D Program of China(No.2023YFA1609000)。
文摘This paper quantitatively discusses the influence of well contact on single-event transient(SET)in sub-20 nm FinFET by two-photon absorption(TPA)pulse laser.Two groups of inverter chains were designed to investigate the impact of well contact distance on the FinFET process.The experimental results show that the SET pulse width has a bimodal symmetric distribution,which is different from that of a bulk planar CMOS device.To investigate the detailed mechanism of the phenomenon,a high-precision FinFET TCAD model was established,in which both Id-Vd and Id-Vg errors were less than 10%compared to the SPICE model provided by the commercial process.TCAD simulation under heavy ion injection showed the mechanism of the abnormal phenomenon,where the well contact plays a major role in charge collection at the near-well contact distance,while the source plays a major role at the far distance.This phenomenon is completely different from that of planar CMOS devices.This indicates that the SET mechanism becomes more complicated during the FinFET process.Therefore,more effective SET hardening methods should be investigated for FinFET.
基金supported by the National Natural Science Foundation of China(42471336,52379021 and 42201278)the Hebei Province Backbone Talent Program,China(Returnee Platform for Overseas Study)(A20240028)+2 种基金the Hebei Province Statistical Science Research Project,China(2024HZ04)the Hebei Province Graduate Education and Teaching Reform Research Project,China(YJG2024046)the Innovation Ability Training Program for Postgraduate Students of Hebei Provincial Department of Education,China(CXZZSS2025048)。
文摘A comprehensive assessment of grain supply,demand,and ecosystem service flows is essential for identifying grain movement pathways,ensuring regional grain security,and guiding sustainable management strategies.However,current studies primarily focus on short-term grain provision services while neglecting the spatiotemporal variations in grain flows across different scales.This gap limits the identification of dynamic matching relationships and the formulation of optimization strategies for balancing grain flows.This study examined the spatiotemporal evolution of grain supply and demand in the Beijing-Tianjin-Hebei(BTH)region from 1980 to 2020.Using the Enhanced TwoStep Floating Catchment Area method,the grain provision ecosystem service flows were quantified,the changes in supply–demand matching under different grain flow scenarios were analyzed and the optimal distance threshold for grain flows was investigated.The results revealed that grain production follows a spatial distribution pattern characterized by high levels in the southeast and low levels in the northwest.A significant mismatch exists between supply and demand,and it shows a scale effect.Deficit areas are mainly concentrated in the northwest,while surplus areas are mainly located in the central and southern regions.As the spatial scale increases,the ecosystem service supply–demand ratio(SDR)classification becomes more clustered,while it exhibits greater spatial SDR heterogeneity at smaller scales.This study examined two distinct scenarios of grain provision ecosystem service flow dynamics based on 100 and 200 km distance thresholds.The flow increased significantly,from 2.17 to 11.81million tons in the first scenario and from 2.41 to 12.37 million tons in the second scenario over nearly 40 years,forming a spatial movement pattern from the central and southern regions to the surrounding areas.Large flows were mainly concentrated in the interior of urban centers,with significant outflows between cities such as Baoding,Shijiazhuang,Xingtai,and Hengshui.At the county scale,supply–demand matching patterns remained consistent between the grain flows in the two scenarios.Notably,incorporating grain flow dynamics significantly reduced the number of grain-deficit areas compared to scenarios without grain flow.In 2020,grain-deficit counties decreased by28.79 and 37.88%,and cities by 12.50 and 25.0%under the two scenarios,respectively.Furthermore,the distance threshold for achieving optimal supply and demand matching at the county scale was longer than at the city scale in both grain flow scenarios.This study provides valuable insights into the dynamic relationships and heterogeneous patterns of grain matching,and expands the research perspective on grain and ecosystem service flows across various spatiotemporal scales.
基金funded by the Key Laboratory of Geological Safety of Coastal Urban Underground Space,Ministry of Natural Resources of China(Grant No.BHKF2022Y02)Natural Science Foundation of Guangdong Province,China(Grant No.2024A1515011162)Natural Science Foundation of Shandong Province,China(Grant No.ZR2024QE021).
文摘Traditional mining in open pit mines often uses explosives,leading to environmental hazards,with flyrock being a critical issue.In detail,excess flying rock beyond the designated explosion area was identified as the primary cause of fatal and non-fatal blasting hazards in open pit mining.Therefore,the accurate and reliable prediction of flyrock becomes crucial for effectively managing and mitigating associated problems.This study used the Light Gradient Boosting Machine(LightGBM)model to predict flyrock in a lead-zinc mine,with promising results.To improve its accuracy,multi-verse optimizer(MVO)and ant lion optimizer(ALO)metaheuristic algorithms were introduced.Results showed MVO-LightGBM outperformed conventional LightGBM.Additionally,decision tree(DT),support vector machine(SVM),and classification and regression tree(CART)models were trained and compared with MVO-LightGBM.The MVO-LightGBM model excelled over DT,SVM,and CART.This study highlights MVO-LightGBM's effectiveness and potential for broader applications.Furthermore,a multiple parametric sensitivity analysis(MPSA)algorithm was employed to specify the sensitivity of parameters.MPSA results indicated that the highest and lowest sensitivities are relevant to blasted rock per hole and spacing with theγ=1752.12 andγ=49.52,respectively.
基金co-supported by the National Natural Science Foundation of China(No.62103432)the China Postdoctoral Science Foundation(No.284881)the Young Talent fund of University Association for Science and Technology in Shaanxi,China(No.20210108)。
文摘Exo-atmospheric vehicles are constrained by limited maneuverability,which leads to the contradiction between evasive maneuver and precision strike.To address the problem of Integrated Evasion and Impact(IEI)decision under multi-constraint conditions,a hierarchical intelligent decision-making method based on Deep Reinforcement Learning(DRL)was proposed.First,an intelligent decision-making framework of“DRL evasion decision”+“impact prediction guidance decision”was established:it takes the impact point deviation correction ability as the constraint and the maximum miss distance as the objective,and effectively solves the problem of poor decisionmaking effect caused by the large IEI decision space.Second,to solve the sparse reward problem faced by evasion decision-making,a hierarchical decision-making method consisting of maneuver timing decision and maneuver duration decision was proposed,and the corresponding Markov Decision Process(MDP)was designed.A detailed simulation experiment was designed to analyze the advantages and computational complexity of the proposed method.Simulation results show that the proposed model has good performance and low computational resource requirement.The minimum miss distance is 21.3 m under the condition of guaranteeing the impact point accuracy,and the single decision-making time is 4.086 ms on an STM32F407 single-chip microcomputer,which has engineering application value.
基金supported in part by the Key Research and Development Program of Shaanxi Province under Grant 2020GY-104in part by the Key Laboratory of Highway Construction Machinery of Shaanxi Province,Key Laboratory of Road Construction Technology and Equipment(Chang'an University),MOE,under Grant 300102250503in part by the Fundamental Research Funds for the Central Universities under Grant CHD 300102250503.
文摘Accurate predictions of the Remaining useful life(RUL)of mechanical equipment are vital for lowering maintenance costs and maintaining equipment reliability and safety.Datadriven RUL prediction methods have made significant progress,but they often assume that the training and testing data have the same distribution,which is often not the case in practical engineering applications.To address this issue,this paper proposes a residual useful life prediction model that combines deep learning and transfer learning.In this model,called transfer convolutional attention mechanism for early-life stage time convolutional network(TCAM-EASTCN),an unsupervised domain adaptation strategy is introduced based on the characterization of subspace distances and orthogonal basis mismatch penalties in the convolutional attention mechanism for early-life stage time convolutional network(CAMEASTCN).This approach minimizes the distribution differences between different domains,enhancing the learning of cross-domain invariant features and effectively reducing the distribution gap between the source and target domains,thereby improving the accuracy of RUL prediction under varying conditions.Experimental results demonstrate that TCAMEASTCN outperforms other models in terms of RUL prediction accuracy and generalization.
基金Supported by NSFC(No.12171062)the Natural Science Foundation of Chongqing(No.CSTB2022NSCQ-JQX0004)+1 种基金the Chongqing Talent Support Program(No.cstc2024ycjh-bgzxm0121)Science and Technology Project of Chongqing Education Committee(No.KJZD-M202300503)。
文摘The purpose of this article is to introduce a new method with a self-adaptive stepsize for approximating a common solution of monotone inclusion problems and variational inequality problems in reflexive Banach spaces.The strong convergence result for our method is established under some standard assumptions without any requirement of the knowledge of the Lipschitz constant of the mapping.Several numerical experiments are provided to verify the advantages and efficiency of proposed algorithms.
文摘K-means uses the sum-of-squared error as the objective function to minimize within-cluster distances.We show that,as a consequence,it also maximizes between-cluster variances.This means that the two measures do not provide complementary information and that using only one is enough.Based on this property,we propose a new objective function called cluster overlap,which is measured intuitively as the proportion of points shared between the clusters.We adopt the new function within k-means and present an algorithm called overlap k-means.It is an alternative way to design a k-means algorithm.A localized variant is also provided by limiting the overlap calculation to the neighboring points.
文摘1.The price of a desk is 10 times the price of a chair.The desk costs 288 yuan more than the chair.How much does one desk and one chair cost?2.A and B start from two different places and walk toward each other.After 4 hours,they meet at a point that is 4 kilometres away from the midpoint between their starting points.A walks faster than B.How many more kilometres per hour does A walk than B?
文摘Background:Bat ear is a congenital condition that can have psychological effects on patients and is readily correctable,often yielding highly satisfactory outcomes for both patients and surgeons.It is crucial to select appropriate techniques in the surgical plan to ensure optimal outcomes.This study aimed to compare the outcomes of otoplasty using the cartilage scoring technique versus the cartilage excision technique for correcting the antihelix.Methods:Twenty patients were divided into two groups:group A underwent the cartilage scoring technique,and group B received the cartilage excision technique.Symmetry,satisfaction,and complications were evaluated and compared between the groups.A visual analog score(VAS)was used to assess the perceived symmetry and satisfaction in both groups.Results:Group A(cartilage scoring technique)demonstrated excellent postoperative symmetry,with a total symmetry score of 96/100 on cartilage grading.In group B,6 of the 10 individuals reported high satisfaction(score:10/10 points on VAS),whereas the remaining 4 reported moderate satisfaction(score:5–9/10 points).The total symmetry score in group B(cartilage excision technique)was 92/100,which was lower than that in group A.No relapses in angle measurements were observed in group A.In contrast,group B showed six average and four slightly overcorrected angle measurements.In group B,the postoperative measures were less satisfactory.Angle measurements were average angles in four cases,and somewhat overcorrected in six.Regarding the helix-to-mastoid distance,three cases were within the average range,whereas seven were slightly overcorrected.No relapses were observed in either group.Concerning complications,we employed minus scoring to measure all complications.Group A had a negative score of19,whereas group B had24.Conclusion:The outcomes were highly satisfactory for patients and surgeons treated using the cartilage scoring technique,and relatively less satisfactory for patients and surgeons treated using the cartilage excision technique.
基金the National Natural Science Foundation of China(Grant No.U22A20171)the National Key Research and Development Program Project of China(2023YFB3709900)+1 种基金the China Baowu Low Carbon Metallurgical Innovation Fund(BWLCF202315)the Pangang-USTB Vanadium and Titanium Research Institute Research Project,the High Steel Center(HSC)at North China University of Technology,Yanshan University and University of Science and Technology Beijing,China.
文摘Model calculations and laboratory experiments were conducted to investigate the influence of surface tension of the molten steel on the agglomeration trend of Al_(2)O_(3) inclusions.The agglomeration trends of inclusions were compared using the calculated attractiveness.When the S content in the steel increased from 2.7×10^(-6) to 789×10^(-6),the surface tension of the molten steel decreased from 1.91 to 1.39 N/m,while the attractive force between inclusions increased from 5×10^(-18) to 5×10^(-16) N,and the critical collision distance of Al_(2)O_(3) inclusions gradually increased from 30 to 70μm.A model of the relationship between the capillary force of inclusions and S content in steel was established.It was found that the capillary force calculated by the model showed the same trend as the attractive force obtained from experiments,and an increase in the S content promoted the attraction between inclusions.
文摘A centrifugal pump with a specific speed ns=67 is considered in this study to investigate the impact of blade cutting(at the outlet edge)on the fluid-induced noise,while keeping all the other geometric parameters unchanged.The required unsteady numerical calculations are conducted by applying the RNG k-εturbulence model with the volute dipole being used as the sound source.The results indicate that the internal pressure energy of the centrifugal pump essentially depends on the blade passing frequency and its low-frequency harmonic frequency.Moreover,the pressure pulsation distribution directly affects the noise caused by the centrifugal pump.The sound pressure inside and outside the centrifugal pump and the sound power at the blade passing frequency gradually decrease increasing cutting distance of the impeller blades.When the cutting percentage is 1.21%,that is,the clearance ratio between impeller blade and tongue is 8.57%,the comprehensive performance of the centrifugal pump is the best.
文摘BACKGROUND Normothermic liver machine perfusion(NMP)is a novel technology used to preserve and evaluate the function of liver allografts.AIM To assess NMP utilization in liver transplant(LT)practices.METHODS All adult deceased-donor LT recipients between January 2021 and September 2023 in the United States were analyzed.Outcomes including discard rates,survival,preservation time and timing of surgery were compared between two groups:NMP vs non-NMP.RESULTS Between 2021 and 2023,NMP was utilized in 1493(6.3%)of all LTs in the United States.Compared to non-NMP group,NMP group had lower allograft discard rate(6.5%vs 10%,P<0.001),older recipients’age(median:47 vs 42 years,P<0.001),and higher utilization of donors from donation after circulatory death(DCD)(55%vs 11%,P<0.001).NMP group also had longer distances between recipient and donor hospitals(median:156 vs 138 miles,P<0.001),longer preser-vation time(median:12.2 vs 5.8 hours,P<0.001),and more daytime reperfusion(74%vs 55%,P<0.001).Post-transplant survival outcomes were comparable between the two groups.In a subgroup analysis of NMP,recipients in the long preservation time(≥8 hours)group had higher daytime reperfusion(78%vs 55%,P<0.001)and similar post-transplant survival when compared to the short preservation time(<8 hours)group.CONCLUSION The utilization of NMP is associated with lower discard rates and increased DCD organs for LT.NMP allows for prolonging the preservation time and increased occurrence of daytime LT,without any impact on the survival outcomes.
基金funded by Research on Intelligent Control System of Variable Fertilization of Deep Application Liquid Fertilizer(GXKS2022GKY003)the Key Laboratory of Smart Agriculture Technology,Guangxi Science and Technology Normal University(GXKSKYPT2024008)+1 种基金Key Laboratory of Detection Technology for Sugarcane and Peanut Leaf Spot Disease,Guangxi Science and Technology Normal University(GXKSKYPT2025008)Research on the Application of Uniformity Theory and 3D Virtual Forest Phase in Harbin Normal University’s Science and Technology Innovation Climbing Program Funding Project(XKB202415)。
文摘Biodiversity has always been valued by ecology,Diversity is generally believed to lead to stability,and biodiversity is an important condition for ecosystems to maintain health.So what factors are related to forest ecosystem biodiversity,and what kind of forest structure affects and determines the size of biodiversity.This study proposes the concept of contained uniformity based on the theory of uniformity,and uses the convergence of contained uniformity to obtain the judgment model of the forest station pattern type.At the same time,it proposes the concept of forest ecosystem distance diversity,and uses the judgment model of the stand pattern type to derive the mathematical definition of forest ecosystem distance diversity.Combining the ecological characteristics of different stand patterns and measurement indicators of forest ecosystem biodiversity,the connection between forest ecosystem distance diversity and biodiversity is derived,and this is used as an indicator to evaluate forest ecosystem biodiversity.Forest ecosystem distance diversity,as an indicator of biodiversity,can not only conduct early assessment and prediction of the biodiversity of immature forests(forests in the early succession or recovery stage),but also provide a quantitative basis for forest structure optimization.Ultimately realize the sustainable development of forestry production and operation and biodiversity protection.
基金support from the Shanghai Science and Technology Foundation Fund under grant No.20070502400the support from the Innovation Program of Shanghai Municipal Education Commission(grant No.2019-0107-00-02-E00032)+4 种基金the support from National Key R&D Program of China grant Nos.2022YFF0503404,2020SKA0110402the CAS Project for Young Scientists in Basic Research(No.YSBR-092)support from the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning and the Shuguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commissionsupported by the National Natural Science Foundation of China(NSFC,Grant Nos.U1931210,12141302,12173026,and 11933002)China Manned Space Project with grant Nos.CMS-CSST-2021-A01,CMS-CSST-2025-A02,CMS-CSST2025-A03,CMS-CSST-2025-A05 and CMS-CSST-2025-A20。
文摘Photometric redshifts of galaxies obtained by multi-wavelength data are widely used in photometric surveys because of their high efficiency.Although various methods have been developed,template fitting is still adopted as one of the most popular approaches.Its accuracy strongly depends on the quality of the spectral energy distribution(SED)templates,which can be calibrated using broadband photometric data from galaxies with known spectroscopic redshifts.Such calibration is expected to improve photometric redshift accuracy,as the calibrated templates will align with observed photometric data more closely.The upcoming China Space Station Telescope(CSST)is one of the Stage IV surveys,which is aiming for high precision cosmological studies.To improve the accuracy of photometric redshift estimation for CSST,we calibrated the CWW+KIN templates using a perturbation algorithm with broadband photometric data from the CSST mock catalog.This calibration used a training set consisting of approximately 4500 galaxies,which is 10%of the total galaxy sample.The outlier fraction and scatter of the photometric redshifts derived from the calibrated templates are 2.55%and 0.036,respectively.Compared to the CWW+KIN templates,these values are reduced by 34%and 23%,respectively.This demonstrates that SED templates calibrated with a small training set can effectively optimize photometric redshift accuracy for future large-scale surveys like CSST,especially with limited spectral training data.
