This paper is concerned with a class of nonlinear fractional differential equations with a disturbance parameter in the integral boundary conditions on the infinite interval.By using Guo-Krasnoselskii fixed point theo...This paper is concerned with a class of nonlinear fractional differential equations with a disturbance parameter in the integral boundary conditions on the infinite interval.By using Guo-Krasnoselskii fixed point theorem,fixed point index theory and the analytic technique,we give the bifurcation point of the parameter which divides the range of parameter for the existence of at least two,one and no positive solutions for the problem.And,by using a fixed point theorem of generalized concave operator and cone theory,we establish the maximum parameter interval for the existence of the unique positive solution for the problem and show that such a positive solution continuously depends on the parameter.In the end,some examples are given to illustrate our main results.展开更多
This paper studies high order compact finite volume methods on non-uniform meshes for one-dimensional elliptic and parabolic differential equations with the Robin boundary conditions.An explicit scheme and an implicit...This paper studies high order compact finite volume methods on non-uniform meshes for one-dimensional elliptic and parabolic differential equations with the Robin boundary conditions.An explicit scheme and an implicit scheme are obtained by discretizing the equivalent integral form of the equation.For the explicit scheme with nodal values,the algebraic system can be solved by the Thomas method.For the implicit scheme with both nodal values and their derivatives,the system can be implemented by a prediction-correction procedure,where in the correction stage,an implicit formula for recovering the nodal derivatives is introduced.Taking two point boundary value problem as an example,we prove that both the explicit and implicit schemes are convergent with fourth order accuracy with respect to some standard discrete norms using the energy method.Two numerical examples demonstrate the correctness and effectiveness of the schemes,as well as the indispensability of using non-uniform meshes.展开更多
Foreign Trade Posts Strong Growth China’s foreign trade has posted a robust start to the year,with the total value of trade in goods surging 18.3 percent year on year in the January–February period,latest official d...Foreign Trade Posts Strong Growth China’s foreign trade has posted a robust start to the year,with the total value of trade in goods surging 18.3 percent year on year in the January–February period,latest official data showed.Data released on 10 March by the General Administration of Customs revealed that total goods trade value had reached 7.73 trillion yuan(about$1.12 trillion)during this period.展开更多
Extreme traffic loads significantly challenge the safety and cost-effectiveness of highway bridges,especially under site-specific traffic conditions.Conventional assessments often rely on overly conservative load mode...Extreme traffic loads significantly challenge the safety and cost-effectiveness of highway bridges,especially under site-specific traffic conditions.Conventional assessments often rely on overly conservative load models,leading to excessive structural design.In this study,a framework for the prediction of maximum bending moments in simply supported bridges is developed by integrating weigh-in-motion(WIM)data,traffic microsimulation,and generalized extreme value(GEV)regression modeling to establish relationships between the GEV parameters(μ,σ,ξ)and traffic factors—heavy vehicle proportion,bridge span length,vehicle speed,headway,and traffic volume.Using one-year WIM data from 7.4 million vehicles,the developed models for μ and σ exhibit high predictive accuracy(R^(2)>0.95)and are validated through leave-one-out cross-validation.The prediction of ξ is less accurate(R^(2)≈0.6),requiring further improvement.Applying these models to a 1000-year return level yields a reliable,data-driven extrapolation,supporting optimized bridge design and safety assessment under varying traffic conditions.展开更多
BACKGROUND:Although the Confusion Assessment Methods for the Intensive Care Unit(CAMICU) is a recommended tool for diagnosing sepsis-associated encephalopathy(SAE),it has several limitations.Mismatch-negativity(MMN) a...BACKGROUND:Although the Confusion Assessment Methods for the Intensive Care Unit(CAMICU) is a recommended tool for diagnosing sepsis-associated encephalopathy(SAE),it has several limitations.Mismatch-negativity(MMN) and P3a are components of event-related potentials(ERPs) used with electroencephalography(EEG) and are associated with cerebral function changes in critically ill patients.This study aimed to provide a quantitative,non-invasive method to guide SAE diagnosis in nonsedated patients.METHODS:From January 2022 to March 2023,sepsis patients without sedation were enrolled and assessed via the CAM-ICU,Glasgow Coma Scale(GCS),and ERP under standard procedures.Both MMN and P3a data were collected.The diagnostic value of MMN and P3a was assessed with processed ERP data.RESULTS:Thirty-six patients were included in this study,comprising 19 patients with SAE and 17 patients without SAE(NSAE).MMN and P3a amplitudes decreased,and only FzMMN amplitude significantly decreased in SAE patients(2.03 [1.08,2.93] mV vs.3.21 [1.92,4.34] mV,P=0.040).After median dichotomization,low F3P3a and FzP3a amplitudes were associated with higher CAM-ICU positivity rates and APACHE II scores.Both amplitude in F3P3a(AUC=0.710,95%CI:0.527–0.893,P=0.034) and FzP3a(AUC=0.700,95%CI:0.519–0.881,P=0.041) exhibited moderate diagnostic efficacy for SAE,while FzMMN amplitude lacks effective diagnostic value.CONCLUSION:In this pilot study,ERP components F3P3a and FzP3a amplitudes demonstrated moderate diagnostic value for SAE.These exploratory findings require confirmation in larger and powered cohorts.展开更多
Weak measurement offers a powerful framework for probing nonclassical features of quantum mechanics,with anomalous weak values serving as operational signatures of contextuality.While the anomalous weak value verifica...Weak measurement offers a powerful framework for probing nonclassical features of quantum mechanics,with anomalous weak values serving as operational signatures of contextuality.While the anomalous weak value verification of quantum contextuality has been predominantly investigated in the single-photon regime and analyzed under approximation condition of infinitesimally small perturbation strength.This study releases the approximation condition and takes into account the impact of perturbation strength on the rigor of the verification.And the investigation on the verification of contextuality is extended to the multi-photon scenarios for observing the influence of the correlation between photons on the verification.Without the limitation of infinitesimally small probability of disturbance,anomalous weak values are identified as necessary for contextuality to emerge,thereby refining the criterion proposed by Pusey[Phys.Rev.Lett.113200401(2014)].In the multi-photon scenarios,the emergence of contextuality also depends strongly on both the photon number and the photon-number distribution state.In particular,contextuality is found to be maximized when the single-photon component dominates and the second-order correlation is lower.These results highlight the critical role of photon statistics in experimental tests of contextuality via anomalous weak values.展开更多
An optimization model has been established and solved to determine the optimal threshold value for the event-triggered self-adaptive optimization strategy,which aims to strike a balance between optimization performanc...An optimization model has been established and solved to determine the optimal threshold value for the event-triggered self-adaptive optimization strategy,which aims to strike a balance between optimization performance and control load while ensuring continuous optimization.First,evaluation indicators are introduced to comprehensively analyze the impact of power fluctuations on the objective function and system voltage at both the system-wide and local levels.Based on these indicators,a multi-stage centralized optimization(MCO)is selectively applied,addressing system state deviations to achieve optimal operating states while maintaining a voltage security margin to ensure system safety.Then,distributed optimization(DO)is carried out at each bus with a renewable energy source or random load integration to accommodate short-term uncertainties using a self-adaptive reactive power algorithm.The optimal threshold value for event-triggered DO is calculated to balance control burden and optimization effectiveness.Utilizing the local state deviation evaluation indicator,unnecessary DOs are skipped when minor power fluctuations occur at the local level.Finally,following the linear superposition principle,event-triggered DOs executed at all distributed controllers collectively constitute the self-adaptive optimization strategy for the entire system.A case study on the IEEE New England 39-bus power system illustrates the effectiveness of the proposed strategy.展开更多
Solar-driven H_(2) production coupled with selective organic transformation represents a promising strategy for co-generation of green hydrogen and high-value chemicals,yet its feasibility relies critically on effecti...Solar-driven H_(2) production coupled with selective organic transformation represents a promising strategy for co-generation of green hydrogen and high-value chemicals,yet its feasibility relies critically on effective bifunctional photocatalysts.Herein,we report the synthesis of ultrafine Cd_(x)Zn_(1-x)S nanocrystals derived from a zeolitic imidazolate framework(ZIF),featuring high surface area,shortened charge diffusion path,and enhanced H_(2) evolution activity.Anchoring amorphous Pt sub-nanoclusters onto these nanocrystals created a bifunctional catalyst(Pt-Cd_(x)Zn_(1-x)S)for efficient lactic acid photoreforming,enabling coproduction of H_(2) with switchable selectivity toward pyruvic acid(PA)or 2,3-dihydroxy-2,3-dimethylsuccinic acid(DTA).The optimized 0.5Pt-Cd_(0.3)Zn_(0.7)S catalyst achieved an exceptional H_(2) production rate of 270.6 mmol h^(-1) g^(-1),73.1%PA selectivity,and 62.8% apparent quantum efficiency at 400 nm.Mechanistic studies revealed that lactic acid undergoes C-H cleavage to form carbon-centered radicals.Pt sub-nanoclusters served as electron sinks to facilitate O-H dissociation and PA formation,whereas pristine Cd_(0.3)Zn_(0.6)7S promoted direct C-C coupling of radicals to predominantly yield DTA.This work offers critical insights for designing advanced bifunctional photocatalysts to integrate solar hydrogen and value-added chemical synthesis.展开更多
Lhasa,one of the world's highest cities,confronts the challenge of harmonizing cultural heritage preservation with ecological protection.Assessing the spatiotemporal dynamics of ecosystem service value(ESV)in its ...Lhasa,one of the world's highest cities,confronts the challenge of harmonizing cultural heritage preservation with ecological protection.Assessing the spatiotemporal dynamics of ecosystem service value(ESV)in its central urban area is therefore critical for informing future urban planning and land management.This study systematically analyzed land use evolution,the spatiotemporal characteristics of ecosystem services,and ecological network construction within Lhasa's central urban area.It integrated multi-source data,including Landsat remote sensing imagery from 2000,2010,and 2023,with multiple modeling methods such as the InVEST model,MaxEnt for cultural service assessment,the Minimum Cumulative Resistance(MCR)model,and circuit theory.Based on these analyses,optimization strategies were proposed.The results indicate that from 2000 to 2023,areas of cultivated land,grassland,and water bodies decreased by 7.47%,6.85%,and 0.68%,respectively,while wetland and forest areas expanded by 1.44%and 0.64%.Construction land exhibited significant expansion(12.94%),leading to an overall ESV reduction of 462.8×10^(5)yuan.Vegetation coverage was identified as the pivotal factor influencing ESV distribution,with higher values concentrated in the Lhasa River Basin and near the Lhalu Wetland,diminishing towards the urban core.Furthermore,spatial autocorrelation analysis revealed significant positive spatial clustering,with low-low aggregation in the eastern and central regions and high-high aggregation in the Lhasa River Basin and its surrounding water bodies.Moreover,based on a comprehensive ecosystem service assessment,11 ecological source sites were identified,primarily in the southwestern mountains and northeastern foothills.A comprehensive resistance surface,incorporating factors such as elevation,Normalized Difference Vegetation Index(NDVI),and land use,facilitated the extraction of 23 potential ecological corridors totaling 124.96 km in length.Topological network analysis indicated high redundancy and connectivity;however,marginal source sites relying on single connections exhibited significant vulnerability to rupture.Additionally,the application of circuit theory identified 30 ecological pinch points(current density≥1.5 A/km^(2))and 23 obstacle points,revealing significant blockages to ecological flow along the Qinghai-Xizang Highway,within the old city,and in other areas of high-intensity human activity.To address the identified network deficiencies—‘scattered cores,fragmented corridors,and insufficient resilience’—this study proposes an optimization strategy conceptualized as‘one vein,three corridors,and multiple cores’.Recommendations for enhancing network resilience include the delineation of ecological protection red lines,the integration of plateau-adapted technologies,and the fostering of community governance mechanisms.This approach aims to provide a scientific basis for constructing an ecological security pattern and promoting sustainable development in plateau cities.Ultimately,this research contributes to the enhancement of ecological well-being in the Himalayan region.展开更多
Maintaining the structural integrity of parallel natural gas pipelines during leakage-induced jet fires remains a critical engineering challenge.Existing methods often fail to account for the complex interactions amon...Maintaining the structural integrity of parallel natural gas pipelines during leakage-induced jet fires remains a critical engineering challenge.Existing methods often fail to account for the complex interactions among heat transfer,material behavior,and pipeline geometry,which can lead to overly simplified and potentially unsafe assessments.To address these limitations,this study develops a multiphysics approach that integrates small-orifice leakage theory with detailed thermo-fluid-structural simulations.The proposed framework contributes to a more accurate failure analysis through three main components:(1)coupled modeling that tracks transient heat flow and stress development as fire conditions evolve;(2)risk assessment incorporating spatial layout,material property changes with temperature,and operational limits;and(3)sensitivity analysis to identify key design factors that influence structural performance under high thermal loads.Simulation results demonstrate that thermal radiation from neighboring jet fires significantly accelerates material degradation,with inter-pipeline spacing emerging as a critical determinant of structural response.Notably,increasing the spacing between pipelines reduces thermal interaction and mechanical stress transfer.As a result,systems with optimized spacing exhibit markedly lower deformation than conventional configurations.These findings provide a foundation for re-evaluating pipeline layout strategies and strengthening safety protocols,particularly in high-risk environments where fire exposure can severely compromise structural reliability.The proposed approach offers actionable guidance for engineers and policymakers seeking to enhance the resilience of pipeline infrastructure under extreme thermal conditions.展开更多
Eucommia ulmoides is an important economic forest tree species in China,of which the different tissues and organs are widely used in traditional medicine for their abundant bioactive ingredients.Previous studies alway...Eucommia ulmoides is an important economic forest tree species in China,of which the different tissues and organs are widely used in traditional medicine for their abundant bioactive ingredients.Previous studies always focused on the Eucommia gum,a potential alternative to natural rubber because of its“rubber plastic duality”.In recent years,Eucommia has increasingly attracted more attention and interest for its excellent nutritional and economic value,with the deepening of research and the development of products involving in the application of bioactive ingredients.However,the dietary health effects and future application prospects of the bioactive components of E.ulmoides have not been systematically summarized.Therefore,we firstly reviewed the main bioactive ingredients category,structural characteristics,extraction methods and nutritive value.Furthermore,we also summarized the wide application of bioactive ingredients in food and medicine fields.Finally,this review provides a comprehensive overview of the safety and future development of products derived from E.ulmoides,as well as exploring potential applications for its bioactive constituents,aiming to facilitate further extensive investigation into its utilization.展开更多
Remote sensing plays a pivotal role in forest inventory by enabling efficient large-scale monitoring while minimizing fieldwork costs.However,missing values pose a critical challenge in remote sensing applications,as ...Remote sensing plays a pivotal role in forest inventory by enabling efficient large-scale monitoring while minimizing fieldwork costs.However,missing values pose a critical challenge in remote sensing applications,as ignoring or mishandling such data gaps can introduce systematic bias into the estimation of target variables for natural resource monitoring.This can lead to cascading errors that propagate through forest and ecosystem management decisions,ultimately hindering progress toward sustainable forest management,biodiversity conservation,and climate change mitigation strategies.This study aims to propose and demonstrate a procedure that employs hybrid estimators to address the limitations of missing remotely sensed data in forest inventory,using Landsat 7 ETM+SLC-off data as an archived source for forest resource monitoring as a case in point.We compared forest inventory estimates from the hybrid estimator with those from a conventional model-based(CMB)estimator using Sentinel-2 data without missing values.Monte Carlo simulations revealed three key findings:(1)The hybrid estimator,leveraging missing-data remote sensing represented by Landsat 7 ETM+SLCoff data,achieved a sampling precision of over 90%,meeting China's national standard for the National Forest Inventory(NFI);(2)The hybrid estimator demonstrated comparable efficiency to the CMB estimator;(3)The uncertainty associated with hybrid estimators was primarily dominated by model parameter estimation,which could be effectively mitigated by slightly increasing the training sample size or refining model specification.Overall,in forest inventory,the hybrid estimator can surmount the limitations posed by missing values in remotely sensed auxiliary data,effectively balancing cost-effectiveness and flexibility.展开更多
Purpose-This study investigates the impact of flagship trains on high-speed railway capacity utilization and develops a brand value-oriented optimization framework that balances service quality enhancement with operat...Purpose-This study investigates the impact of flagship trains on high-speed railway capacity utilization and develops a brand value-oriented optimization framework that balances service quality enhancement with operational efficiency.Design/methodology/approach-A mathematical optimization model based on integer programming is developed,incorporating flagship train constraints into capacity optimization.Case studies compare scenarios with and without flagship train considerations using the Beijing-Shanghai High-Speed Railway data across 20 experimental groups.Findings-Operating flagship trains with hourly departure constraints results in an average decrease of 0.9 trains and an 8.4%reduction in capacity utilization rate.When scheduling 2 flagship trains within a 2-h timeframe,capacity utilization decreases from 86.43%to 83.73%,quantifying the trade-off between brand positioning and operational capacity.Originality/value-This research provides the first quantitative framework for brand value-oriented railway capacity optimization,establishing clear definitions for flagship trains and mathematical foundations for evaluating service quality versus efficiency trade-offs.The findings offer practical decision support for railway operators balancing competitive positioning with capacity maximization.展开更多
In the Tianshan region,a complete textile industry chain has been established,covering the entire process from cotton cultivation and chemical fiber production,through spinning,weaving,dyeing,and finishing,and further...In the Tianshan region,a complete textile industry chain has been established,covering the entire process from cotton cultivation and chemical fiber production,through spinning,weaving,dyeing,and finishing,and further extending to apparel,home textiles,and industrial textiles.In November 2025,the first list of five characteristic textile and apparel industry clusters in Xinjiang was officially announced,marking a new stage in the clustering of Xinjiang's textile and apparel industry.Data shows that the total output value of Xinjiang's cotton and textile and apparel industry chain has exceeded 220 billion yuan.With the nation's largest cotton production,a complete industrial chain system,and strong synergistic effects,Xinjiang has become a leading and highly competitive textile industry hub in China.展开更多
The shift toward specialized and large-scale agricultural production has spurred the emergence of agricultural clusters as key forces of rural vitalization and sustainable development.This paper explored the formation...The shift toward specialized and large-scale agricultural production has spurred the emergence of agricultural clusters as key forces of rural vitalization and sustainable development.This paper explored the formation and evolution of Meizhou pomelo industry cluster in China,focusing on its role in restructuring rural socio-economic systems and integrating the whole value chains.Based on a case study employing qualitative methods such as in-depth interviews and participatory observation,the agricultural cluster evolution of Meizhou pomelo was categorized into three key phases of initial decentralization,self-organized scaling,and reorganized clustering.Geographical proximity and industrial agglomeration constitute the physical foundation,while vertical/horizontal linkages,technologic-al innovation,and policy support enhance competitiveness.Special mechanisms emerge through localized social networks,farmer co-operatives’activation,and cross-regional market expansion.The cluster’s impact is manifested in the shift from extensive to standard-ized and modernized production,diversified and flexible livelihood of farmers,and the integration of agriculture with industry and ser-vices.The development of the whole value chain based on agricultural cluster represents a critical pathway for achieving agricultural modernization,encompassing both internal and external value chain optimization.Through quality assurance systems,product diversi-fication strategies,operational efficiency improvements,and brand enhancement,these clusters amplify product value propositions and market competitiveness.This systemic approach facilitates supply-demand coordination,enables resource synergies,and optimizes eco-nomic returns across the horizontal and vertical value chain.This paper argues that agricultural clusters serve as strategic catalysts for sustainable rural development by reconstructing local production systems,fostering innovation ecosystems,and aligning agricultural modernization.It contributes to debates on rural vitalization by demonstrating how agricultural clustering can reconfigure rural areas as hubs of ecological modernization,rather than mere urban peripheries.展开更多
The Double Take column looks at a single topic from an African and Chinese perspective.This month,we discuss how to understand the growing emphasis on emotional returns among young people.Emotional value has emerged a...The Double Take column looks at a single topic from an African and Chinese perspective.This month,we discuss how to understand the growing emphasis on emotional returns among young people.Emotional value has emerged as a central force shaping youth decision-making across work,consumption,relationships and lifestyle choices.Unlike traditional economic rationality that prioritises income and material security,emotional value focuses on how choices make individuals feel and how they align with personal meaning.This shift is particularly evident in rapidly transforming societies such as China and Ghana,where economic restructuring,globalisation and social change have reshaped pathways to adulthood.展开更多
AIM:To evaluate the predictive value of pan-immuneinflammation value(PIV)in the diagnosis of proliferative diabetic retinopathy(PDR)and its association with the stage of PDR.METHODS:This observational case-control stu...AIM:To evaluate the predictive value of pan-immuneinflammation value(PIV)in the diagnosis of proliferative diabetic retinopathy(PDR)and its association with the stage of PDR.METHODS:This observational case-control study included participants who underwent routine complete blood count testing.Inflammation-related indices,including neutrophil-to-lymphocyte ratio,systemic immune-inflammation index(SII),and PIV,were derived and analyzed.Receiver operating characteristic curve(ROC)analysis was applied to assess the diagnostic performance of these indices in distinguishing patients with PDR,with sensitivity,specificity,area under ROC,and optimal threshold values calculated.In addition,binary logistic regression analysis was performed to evaluate the association between inflammatory indices and PDR stage.RESULTS:This study included 205 patients:60 with diabetes without retinopathy(mean age:61.81±10.76y),80 with PDR(mean age:61.63±10.03y)and 65 healthy controls(mean age:59.52±5.88y).The PDR group had significantly higher white blood cell(WBC,P<0.001),monocyte(MONO,P=0.009)and neutrophil(NEU)counts(P<0.001).SII and PIV had the highest sensitivity and area under ROC for predicting patients with PDR(0.822,0.846,respectively).The optimal cut-off values for discriminating patients with PDR were determined to be>527.12 and>299.08 for SII and PIV,respectively.The logistic regression analysis demonstrated that a decrease in lymphocyte(LYM)count and an increase in platelet count(PLT),glycated haemoglobin(HbA1c),SII,and PIV were all significantly associated with the development of high-risk PDR(all P<0.05).PIV was more stable than independent MONO,LYM,PLT and NEU levels in predicting both the diagnosis and stage of PDR.The optimal cut-off value for PIV to discriminate patients with high-risk PDR was found to be>345.87 area under ROC=0.871,with sensitivity of 0.827 and specificity of 0.812.CONCLUSION:PIV is a reliable,valuable,and inexpensive blood index that can be used for early detection and staging of PDR.PIV may therefore be essential to be used for the follow-up of diabetic patients.展开更多
In this paper,we study the nonlinear Riemann boundary value problem with square roots that is represented by a Cauchy-type integral with kernel density in variable exponent Lebesgue spaces.We discuss the odd-order zer...In this paper,we study the nonlinear Riemann boundary value problem with square roots that is represented by a Cauchy-type integral with kernel density in variable exponent Lebesgue spaces.We discuss the odd-order zero-points distribution of the solutions and separate the single valued analytic branch of the solutions with square roots,then convert the problem to a Riemann boundary value problem in variable exponent Lebesgue spaces and discuss the singularity of solutions at individual zeros belonging to curve.We consider two types of cases those where the coefficient is Hölder and those where it is piecewise Hölder.Then we solve the Hilbert boundary value problem with square roots in variable exponent Lebesgue spaces.By discussing the distribution of the odd-order zero-points for solutions and the method of symmetric extension,we convert the Hilbert problem to a Riemann boundary value problem.The equivalence of the transformation is discussed.Finally,we get the solvable conditions and the direct expressions of the solutions in variable exponent Lebesgue spaces.展开更多
基金Supported by the National Natural Science Foundation of China(11361047)Fundamental Research Program of Shanxi Province(20210302124529)。
文摘This paper is concerned with a class of nonlinear fractional differential equations with a disturbance parameter in the integral boundary conditions on the infinite interval.By using Guo-Krasnoselskii fixed point theorem,fixed point index theory and the analytic technique,we give the bifurcation point of the parameter which divides the range of parameter for the existence of at least two,one and no positive solutions for the problem.And,by using a fixed point theorem of generalized concave operator and cone theory,we establish the maximum parameter interval for the existence of the unique positive solution for the problem and show that such a positive solution continuously depends on the parameter.In the end,some examples are given to illustrate our main results.
文摘This paper studies high order compact finite volume methods on non-uniform meshes for one-dimensional elliptic and parabolic differential equations with the Robin boundary conditions.An explicit scheme and an implicit scheme are obtained by discretizing the equivalent integral form of the equation.For the explicit scheme with nodal values,the algebraic system can be solved by the Thomas method.For the implicit scheme with both nodal values and their derivatives,the system can be implemented by a prediction-correction procedure,where in the correction stage,an implicit formula for recovering the nodal derivatives is introduced.Taking two point boundary value problem as an example,we prove that both the explicit and implicit schemes are convergent with fourth order accuracy with respect to some standard discrete norms using the energy method.Two numerical examples demonstrate the correctness and effectiveness of the schemes,as well as the indispensability of using non-uniform meshes.
文摘Foreign Trade Posts Strong Growth China’s foreign trade has posted a robust start to the year,with the total value of trade in goods surging 18.3 percent year on year in the January–February period,latest official data showed.Data released on 10 March by the General Administration of Customs revealed that total goods trade value had reached 7.73 trillion yuan(about$1.12 trillion)during this period.
基金The National Natural Science Foundation of China(No.52278149)the Natural Science Foundation of Jiangsu Province(No.BZ2024015)+1 种基金the Opening Project of State Key Laboratory for Track Technology of High-Speed Railway(No.2023YJ375)the Opening Project of Zhejiang Engineering Centre of Road and Bridge Intelligent Operation and Maintenance Technology(No.202402G).
文摘Extreme traffic loads significantly challenge the safety and cost-effectiveness of highway bridges,especially under site-specific traffic conditions.Conventional assessments often rely on overly conservative load models,leading to excessive structural design.In this study,a framework for the prediction of maximum bending moments in simply supported bridges is developed by integrating weigh-in-motion(WIM)data,traffic microsimulation,and generalized extreme value(GEV)regression modeling to establish relationships between the GEV parameters(μ,σ,ξ)and traffic factors—heavy vehicle proportion,bridge span length,vehicle speed,headway,and traffic volume.Using one-year WIM data from 7.4 million vehicles,the developed models for μ and σ exhibit high predictive accuracy(R^(2)>0.95)and are validated through leave-one-out cross-validation.The prediction of ξ is less accurate(R^(2)≈0.6),requiring further improvement.Applying these models to a 1000-year return level yields a reliable,data-driven extrapolation,supporting optimized bridge design and safety assessment under varying traffic conditions.
基金supported by the CAMS Innovation Fund for Medical Sciences (CIFMS)(No.2021-1-I2M-020)National High Level Hospital Clinical Research Funding (No.2022-PUMCH-B-109)National Natural Science Foundation of China (82402543)。
文摘BACKGROUND:Although the Confusion Assessment Methods for the Intensive Care Unit(CAMICU) is a recommended tool for diagnosing sepsis-associated encephalopathy(SAE),it has several limitations.Mismatch-negativity(MMN) and P3a are components of event-related potentials(ERPs) used with electroencephalography(EEG) and are associated with cerebral function changes in critically ill patients.This study aimed to provide a quantitative,non-invasive method to guide SAE diagnosis in nonsedated patients.METHODS:From January 2022 to March 2023,sepsis patients without sedation were enrolled and assessed via the CAM-ICU,Glasgow Coma Scale(GCS),and ERP under standard procedures.Both MMN and P3a data were collected.The diagnostic value of MMN and P3a was assessed with processed ERP data.RESULTS:Thirty-six patients were included in this study,comprising 19 patients with SAE and 17 patients without SAE(NSAE).MMN and P3a amplitudes decreased,and only FzMMN amplitude significantly decreased in SAE patients(2.03 [1.08,2.93] mV vs.3.21 [1.92,4.34] mV,P=0.040).After median dichotomization,low F3P3a and FzP3a amplitudes were associated with higher CAM-ICU positivity rates and APACHE II scores.Both amplitude in F3P3a(AUC=0.710,95%CI:0.527–0.893,P=0.034) and FzP3a(AUC=0.700,95%CI:0.519–0.881,P=0.041) exhibited moderate diagnostic efficacy for SAE,while FzMMN amplitude lacks effective diagnostic value.CONCLUSION:In this pilot study,ERP components F3P3a and FzP3a amplitudes demonstrated moderate diagnostic value for SAE.These exploratory findings require confirmation in larger and powered cohorts.
基金Project supported by the National Natural Science Foun-dation of China(Grant Nos.62371199 and 62071186)the Natural Science Foundation of Guangdong Province,China(Grant No.2024A1515012427)+1 种基金the Quantum Science Strate-gic Initiative Project of Guangdong Province,China(Grant No.GDZX2305001)the Key Laboratory Project of Guangdong Province,China(Grant No.2020B1212060066).
文摘Weak measurement offers a powerful framework for probing nonclassical features of quantum mechanics,with anomalous weak values serving as operational signatures of contextuality.While the anomalous weak value verification of quantum contextuality has been predominantly investigated in the single-photon regime and analyzed under approximation condition of infinitesimally small perturbation strength.This study releases the approximation condition and takes into account the impact of perturbation strength on the rigor of the verification.And the investigation on the verification of contextuality is extended to the multi-photon scenarios for observing the influence of the correlation between photons on the verification.Without the limitation of infinitesimally small probability of disturbance,anomalous weak values are identified as necessary for contextuality to emerge,thereby refining the criterion proposed by Pusey[Phys.Rev.Lett.113200401(2014)].In the multi-photon scenarios,the emergence of contextuality also depends strongly on both the photon number and the photon-number distribution state.In particular,contextuality is found to be maximized when the single-photon component dominates and the second-order correlation is lower.These results highlight the critical role of photon statistics in experimental tests of contextuality via anomalous weak values.
基金supported in part by National Key R&D Program of China(2022YFF0610600).
文摘An optimization model has been established and solved to determine the optimal threshold value for the event-triggered self-adaptive optimization strategy,which aims to strike a balance between optimization performance and control load while ensuring continuous optimization.First,evaluation indicators are introduced to comprehensively analyze the impact of power fluctuations on the objective function and system voltage at both the system-wide and local levels.Based on these indicators,a multi-stage centralized optimization(MCO)is selectively applied,addressing system state deviations to achieve optimal operating states while maintaining a voltage security margin to ensure system safety.Then,distributed optimization(DO)is carried out at each bus with a renewable energy source or random load integration to accommodate short-term uncertainties using a self-adaptive reactive power algorithm.The optimal threshold value for event-triggered DO is calculated to balance control burden and optimization effectiveness.Utilizing the local state deviation evaluation indicator,unnecessary DOs are skipped when minor power fluctuations occur at the local level.Finally,following the linear superposition principle,event-triggered DOs executed at all distributed controllers collectively constitute the self-adaptive optimization strategy for the entire system.A case study on the IEEE New England 39-bus power system illustrates the effectiveness of the proposed strategy.
基金supported by the National Natural Science Foundation of China(Grant 52276212)the National Key Research and Development Program of China(Grant 2022YFB3803600)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant BK20231211)the China Fundamental Research Funds for the Central Universities.
文摘Solar-driven H_(2) production coupled with selective organic transformation represents a promising strategy for co-generation of green hydrogen and high-value chemicals,yet its feasibility relies critically on effective bifunctional photocatalysts.Herein,we report the synthesis of ultrafine Cd_(x)Zn_(1-x)S nanocrystals derived from a zeolitic imidazolate framework(ZIF),featuring high surface area,shortened charge diffusion path,and enhanced H_(2) evolution activity.Anchoring amorphous Pt sub-nanoclusters onto these nanocrystals created a bifunctional catalyst(Pt-Cd_(x)Zn_(1-x)S)for efficient lactic acid photoreforming,enabling coproduction of H_(2) with switchable selectivity toward pyruvic acid(PA)or 2,3-dihydroxy-2,3-dimethylsuccinic acid(DTA).The optimized 0.5Pt-Cd_(0.3)Zn_(0.7)S catalyst achieved an exceptional H_(2) production rate of 270.6 mmol h^(-1) g^(-1),73.1%PA selectivity,and 62.8% apparent quantum efficiency at 400 nm.Mechanistic studies revealed that lactic acid undergoes C-H cleavage to form carbon-centered radicals.Pt sub-nanoclusters served as electron sinks to facilitate O-H dissociation and PA formation,whereas pristine Cd_(0.3)Zn_(0.6)7S promoted direct C-C coupling of radicals to predominantly yield DTA.This work offers critical insights for designing advanced bifunctional photocatalysts to integrate solar hydrogen and value-added chemical synthesis.
基金National Natural Science Foundation of China Youth Fund Project:Research on the Construction of Ecological Security Pattern in the Transition Zone of Nature Reserves along the Sichuan-Xizang Railway(Western Sichuan Section)(51908470).
文摘Lhasa,one of the world's highest cities,confronts the challenge of harmonizing cultural heritage preservation with ecological protection.Assessing the spatiotemporal dynamics of ecosystem service value(ESV)in its central urban area is therefore critical for informing future urban planning and land management.This study systematically analyzed land use evolution,the spatiotemporal characteristics of ecosystem services,and ecological network construction within Lhasa's central urban area.It integrated multi-source data,including Landsat remote sensing imagery from 2000,2010,and 2023,with multiple modeling methods such as the InVEST model,MaxEnt for cultural service assessment,the Minimum Cumulative Resistance(MCR)model,and circuit theory.Based on these analyses,optimization strategies were proposed.The results indicate that from 2000 to 2023,areas of cultivated land,grassland,and water bodies decreased by 7.47%,6.85%,and 0.68%,respectively,while wetland and forest areas expanded by 1.44%and 0.64%.Construction land exhibited significant expansion(12.94%),leading to an overall ESV reduction of 462.8×10^(5)yuan.Vegetation coverage was identified as the pivotal factor influencing ESV distribution,with higher values concentrated in the Lhasa River Basin and near the Lhalu Wetland,diminishing towards the urban core.Furthermore,spatial autocorrelation analysis revealed significant positive spatial clustering,with low-low aggregation in the eastern and central regions and high-high aggregation in the Lhasa River Basin and its surrounding water bodies.Moreover,based on a comprehensive ecosystem service assessment,11 ecological source sites were identified,primarily in the southwestern mountains and northeastern foothills.A comprehensive resistance surface,incorporating factors such as elevation,Normalized Difference Vegetation Index(NDVI),and land use,facilitated the extraction of 23 potential ecological corridors totaling 124.96 km in length.Topological network analysis indicated high redundancy and connectivity;however,marginal source sites relying on single connections exhibited significant vulnerability to rupture.Additionally,the application of circuit theory identified 30 ecological pinch points(current density≥1.5 A/km^(2))and 23 obstacle points,revealing significant blockages to ecological flow along the Qinghai-Xizang Highway,within the old city,and in other areas of high-intensity human activity.To address the identified network deficiencies—‘scattered cores,fragmented corridors,and insufficient resilience’—this study proposes an optimization strategy conceptualized as‘one vein,three corridors,and multiple cores’.Recommendations for enhancing network resilience include the delineation of ecological protection red lines,the integration of plateau-adapted technologies,and the fostering of community governance mechanisms.This approach aims to provide a scientific basis for constructing an ecological security pattern and promoting sustainable development in plateau cities.Ultimately,this research contributes to the enhancement of ecological well-being in the Himalayan region.
文摘Maintaining the structural integrity of parallel natural gas pipelines during leakage-induced jet fires remains a critical engineering challenge.Existing methods often fail to account for the complex interactions among heat transfer,material behavior,and pipeline geometry,which can lead to overly simplified and potentially unsafe assessments.To address these limitations,this study develops a multiphysics approach that integrates small-orifice leakage theory with detailed thermo-fluid-structural simulations.The proposed framework contributes to a more accurate failure analysis through three main components:(1)coupled modeling that tracks transient heat flow and stress development as fire conditions evolve;(2)risk assessment incorporating spatial layout,material property changes with temperature,and operational limits;and(3)sensitivity analysis to identify key design factors that influence structural performance under high thermal loads.Simulation results demonstrate that thermal radiation from neighboring jet fires significantly accelerates material degradation,with inter-pipeline spacing emerging as a critical determinant of structural response.Notably,increasing the spacing between pipelines reduces thermal interaction and mechanical stress transfer.As a result,systems with optimized spacing exhibit markedly lower deformation than conventional configurations.These findings provide a foundation for re-evaluating pipeline layout strategies and strengthening safety protocols,particularly in high-risk environments where fire exposure can severely compromise structural reliability.The proposed approach offers actionable guidance for engineers and policymakers seeking to enhance the resilience of pipeline infrastructure under extreme thermal conditions.
基金financially supported by the National Natural Science Foundation of China(32201586 and 32301760)Key Specialized Research and Development Program in Henan Province(232102110218)+1 种基金Postdoctoral Research Start-Up Fund of Henan Province(HN2022112)Special Fund for Young Talents in Henan Agricultural University(30501318).
文摘Eucommia ulmoides is an important economic forest tree species in China,of which the different tissues and organs are widely used in traditional medicine for their abundant bioactive ingredients.Previous studies always focused on the Eucommia gum,a potential alternative to natural rubber because of its“rubber plastic duality”.In recent years,Eucommia has increasingly attracted more attention and interest for its excellent nutritional and economic value,with the deepening of research and the development of products involving in the application of bioactive ingredients.However,the dietary health effects and future application prospects of the bioactive components of E.ulmoides have not been systematically summarized.Therefore,we firstly reviewed the main bioactive ingredients category,structural characteristics,extraction methods and nutritive value.Furthermore,we also summarized the wide application of bioactive ingredients in food and medicine fields.Finally,this review provides a comprehensive overview of the safety and future development of products derived from E.ulmoides,as well as exploring potential applications for its bioactive constituents,aiming to facilitate further extensive investigation into its utilization.
基金supported by the National Key R&D Program of China(No.2023YFF1304002-05)the National Social Science Fund of China(No.22BTJ005)the National Natural Science Foundation of China(No.32572049)。
文摘Remote sensing plays a pivotal role in forest inventory by enabling efficient large-scale monitoring while minimizing fieldwork costs.However,missing values pose a critical challenge in remote sensing applications,as ignoring or mishandling such data gaps can introduce systematic bias into the estimation of target variables for natural resource monitoring.This can lead to cascading errors that propagate through forest and ecosystem management decisions,ultimately hindering progress toward sustainable forest management,biodiversity conservation,and climate change mitigation strategies.This study aims to propose and demonstrate a procedure that employs hybrid estimators to address the limitations of missing remotely sensed data in forest inventory,using Landsat 7 ETM+SLC-off data as an archived source for forest resource monitoring as a case in point.We compared forest inventory estimates from the hybrid estimator with those from a conventional model-based(CMB)estimator using Sentinel-2 data without missing values.Monte Carlo simulations revealed three key findings:(1)The hybrid estimator,leveraging missing-data remote sensing represented by Landsat 7 ETM+SLCoff data,achieved a sampling precision of over 90%,meeting China's national standard for the National Forest Inventory(NFI);(2)The hybrid estimator demonstrated comparable efficiency to the CMB estimator;(3)The uncertainty associated with hybrid estimators was primarily dominated by model parameter estimation,which could be effectively mitigated by slightly increasing the training sample size or refining model specification.Overall,in forest inventory,the hybrid estimator can surmount the limitations posed by missing values in remotely sensed auxiliary data,effectively balancing cost-effectiveness and flexibility.
基金funded by the Science and Technology Research and Development Program Project of China Railway Group Co.,Ltd,grant number P2024X002the China Academy of Railway Sciences Corporation Limited,grant number 2024YJ154.
文摘Purpose-This study investigates the impact of flagship trains on high-speed railway capacity utilization and develops a brand value-oriented optimization framework that balances service quality enhancement with operational efficiency.Design/methodology/approach-A mathematical optimization model based on integer programming is developed,incorporating flagship train constraints into capacity optimization.Case studies compare scenarios with and without flagship train considerations using the Beijing-Shanghai High-Speed Railway data across 20 experimental groups.Findings-Operating flagship trains with hourly departure constraints results in an average decrease of 0.9 trains and an 8.4%reduction in capacity utilization rate.When scheduling 2 flagship trains within a 2-h timeframe,capacity utilization decreases from 86.43%to 83.73%,quantifying the trade-off between brand positioning and operational capacity.Originality/value-This research provides the first quantitative framework for brand value-oriented railway capacity optimization,establishing clear definitions for flagship trains and mathematical foundations for evaluating service quality versus efficiency trade-offs.The findings offer practical decision support for railway operators balancing competitive positioning with capacity maximization.
文摘In the Tianshan region,a complete textile industry chain has been established,covering the entire process from cotton cultivation and chemical fiber production,through spinning,weaving,dyeing,and finishing,and further extending to apparel,home textiles,and industrial textiles.In November 2025,the first list of five characteristic textile and apparel industry clusters in Xinjiang was officially announced,marking a new stage in the clustering of Xinjiang's textile and apparel industry.Data shows that the total output value of Xinjiang's cotton and textile and apparel industry chain has exceeded 220 billion yuan.With the nation's largest cotton production,a complete industrial chain system,and strong synergistic effects,Xinjiang has become a leading and highly competitive textile industry hub in China.
基金Under the auspices of the Key Projects of Philosophy and Social Sciences Research,Ministry of Education of China(No.23JZD008)National Natural Science Foundation of China(No.42171193)+2 种基金Key Project of Guangdong Provincial Philosophy and Social Sciences Planning(No.GD24ES013,GD25ZX04)2025 Guangzhou Basic and Applied Basic Research Special Project(No.2025A04J7127)Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.24wkjc11)。
文摘The shift toward specialized and large-scale agricultural production has spurred the emergence of agricultural clusters as key forces of rural vitalization and sustainable development.This paper explored the formation and evolution of Meizhou pomelo industry cluster in China,focusing on its role in restructuring rural socio-economic systems and integrating the whole value chains.Based on a case study employing qualitative methods such as in-depth interviews and participatory observation,the agricultural cluster evolution of Meizhou pomelo was categorized into three key phases of initial decentralization,self-organized scaling,and reorganized clustering.Geographical proximity and industrial agglomeration constitute the physical foundation,while vertical/horizontal linkages,technologic-al innovation,and policy support enhance competitiveness.Special mechanisms emerge through localized social networks,farmer co-operatives’activation,and cross-regional market expansion.The cluster’s impact is manifested in the shift from extensive to standard-ized and modernized production,diversified and flexible livelihood of farmers,and the integration of agriculture with industry and ser-vices.The development of the whole value chain based on agricultural cluster represents a critical pathway for achieving agricultural modernization,encompassing both internal and external value chain optimization.Through quality assurance systems,product diversi-fication strategies,operational efficiency improvements,and brand enhancement,these clusters amplify product value propositions and market competitiveness.This systemic approach facilitates supply-demand coordination,enables resource synergies,and optimizes eco-nomic returns across the horizontal and vertical value chain.This paper argues that agricultural clusters serve as strategic catalysts for sustainable rural development by reconstructing local production systems,fostering innovation ecosystems,and aligning agricultural modernization.It contributes to debates on rural vitalization by demonstrating how agricultural clustering can reconfigure rural areas as hubs of ecological modernization,rather than mere urban peripheries.
文摘The Double Take column looks at a single topic from an African and Chinese perspective.This month,we discuss how to understand the growing emphasis on emotional returns among young people.Emotional value has emerged as a central force shaping youth decision-making across work,consumption,relationships and lifestyle choices.Unlike traditional economic rationality that prioritises income and material security,emotional value focuses on how choices make individuals feel and how they align with personal meaning.This shift is particularly evident in rapidly transforming societies such as China and Ghana,where economic restructuring,globalisation and social change have reshaped pathways to adulthood.
文摘AIM:To evaluate the predictive value of pan-immuneinflammation value(PIV)in the diagnosis of proliferative diabetic retinopathy(PDR)and its association with the stage of PDR.METHODS:This observational case-control study included participants who underwent routine complete blood count testing.Inflammation-related indices,including neutrophil-to-lymphocyte ratio,systemic immune-inflammation index(SII),and PIV,were derived and analyzed.Receiver operating characteristic curve(ROC)analysis was applied to assess the diagnostic performance of these indices in distinguishing patients with PDR,with sensitivity,specificity,area under ROC,and optimal threshold values calculated.In addition,binary logistic regression analysis was performed to evaluate the association between inflammatory indices and PDR stage.RESULTS:This study included 205 patients:60 with diabetes without retinopathy(mean age:61.81±10.76y),80 with PDR(mean age:61.63±10.03y)and 65 healthy controls(mean age:59.52±5.88y).The PDR group had significantly higher white blood cell(WBC,P<0.001),monocyte(MONO,P=0.009)and neutrophil(NEU)counts(P<0.001).SII and PIV had the highest sensitivity and area under ROC for predicting patients with PDR(0.822,0.846,respectively).The optimal cut-off values for discriminating patients with PDR were determined to be>527.12 and>299.08 for SII and PIV,respectively.The logistic regression analysis demonstrated that a decrease in lymphocyte(LYM)count and an increase in platelet count(PLT),glycated haemoglobin(HbA1c),SII,and PIV were all significantly associated with the development of high-risk PDR(all P<0.05).PIV was more stable than independent MONO,LYM,PLT and NEU levels in predicting both the diagnosis and stage of PDR.The optimal cut-off value for PIV to discriminate patients with high-risk PDR was found to be>345.87 area under ROC=0.871,with sensitivity of 0.827 and specificity of 0.812.CONCLUSION:PIV is a reliable,valuable,and inexpensive blood index that can be used for early detection and staging of PDR.PIV may therefore be essential to be used for the follow-up of diabetic patients.
基金supported by the National Natural Science Foundation of China(11601525)the Natural Science Foundation of Hunan Province(2024JJ5412),the Changsha Municipal Natural Science Foundation(kq2402193).
文摘In this paper,we study the nonlinear Riemann boundary value problem with square roots that is represented by a Cauchy-type integral with kernel density in variable exponent Lebesgue spaces.We discuss the odd-order zero-points distribution of the solutions and separate the single valued analytic branch of the solutions with square roots,then convert the problem to a Riemann boundary value problem in variable exponent Lebesgue spaces and discuss the singularity of solutions at individual zeros belonging to curve.We consider two types of cases those where the coefficient is Hölder and those where it is piecewise Hölder.Then we solve the Hilbert boundary value problem with square roots in variable exponent Lebesgue spaces.By discussing the distribution of the odd-order zero-points for solutions and the method of symmetric extension,we convert the Hilbert problem to a Riemann boundary value problem.The equivalence of the transformation is discussed.Finally,we get the solvable conditions and the direct expressions of the solutions in variable exponent Lebesgue spaces.
