Recently,information acquired at the canopy top,such as spectral and textural data,has been widely used to estimate plant nitrogen(N)accumulation(PNA).The response of crops to N uptake involves not only changes in hor...Recently,information acquired at the canopy top,such as spectral and textural data,has been widely used to estimate plant nitrogen(N)accumulation(PNA).The response of crops to N uptake involves not only changes in horizontal canopy top information but also an increase in vertical plant height(PH).It remains unclear whether the fusion of spectral indices with PH can improve the estimation performance of PNA models based on spectral remote sensing across different growth stages.展开更多
In this paper,a nonlinear control approach for an unstable networked plant in the presence of actuator and sensor limitations using robust right coprime factorization is proposed.The actuator is limited by upper and l...In this paper,a nonlinear control approach for an unstable networked plant in the presence of actuator and sensor limitations using robust right coprime factorization is proposed.The actuator is limited by upper and lower constraints and the sensor in the feedback loop is subjected to network-induced unknown time-varying delay and noise.With this nonlinear control method,we first employ right coprime factorization based on isomorphism and operator theory to factorize the plant,so that bounded input bounded output(BIBO)stability can be guaranteed.Next,continuous-time generalized predictive control(CGPC)is utilized for the unstable operator of the right coprime factorized plant to guarantee inner stability and enables the closed-loop dynamics of the system with predictive characteristics.Meanwhile,a second-Do F(degrees of freedom)switched controller that satisfies a perturbed Bezout identity and a robustness condition is designed.By using the CGPC controller that possesses predictive behavior and the second-Do F switched stabilizer,the overall stability of the plant subjected to actuator limitations is guaranteed.To address sensor limitations that exist in networked plants in the form of delay and noise which often cause system performance degradation,we implement an identity operator definition in the feedback loop to compensate for these adverse effects.Further,a pre-operator is designed to ensure that the plant output tracks the reference input.Finally,the effectiveness of the proposed design scheme is demonstrated by simulations.展开更多
Objective:To evaluate the effectiveness of the internal limiting membrane(ILM)flipping and covering technique in the treatment of patients with high myopic macular hole(HMMH).Methods:One hundred and two patients with ...Objective:To evaluate the effectiveness of the internal limiting membrane(ILM)flipping and covering technique in the treatment of patients with high myopic macular hole(HMMH).Methods:One hundred and two patients with HMMH who were admitted to the hospital from June 2019 to June 2024 were selected.The minimum diameter of the macular hole(MH)in all patients was≤500μm.The patients were randomly divided into two groups.The experimental group received 25G pars plana vitrectomy(PPV)combined with ILM flipping and covering technique,while the reference group received PPV combined with ILM peeling.The efficacy indicators and best corrected visual acuity levels were compared between the two groups.Results:The MH closure rate and retinal reattachment rate were higher in the experimental group than in the reference group at 3 and 6 months postoperatively(P<0.05).The best corrected visual acuity level was higher in the experimental group than in the reference group at 3 and 6 months postoperatively(P<0.05).The Chinese version of the Visual Function-Related Quality of Life Questionnaire-25(CVRQOL-25)score was higher in the experimental group than in the reference group at 3 and 6 months postoperatively(P<0.05).No serious complications were observed in both groups postoperatively,and there was no difference between the two groups(P>0.05).Conclusion:The ILM flipping and covering technique can improve the MH closure rate and retinal reattachment rate in patients with HMMH(diameter≤500μm),enhance the best corrected visual acuity level,and improve the quality of life related to visual function,with fewer postoperative complications.展开更多
This article examines the influence of annealing temperature on fracture toughness and forming limit curves of dissimilar aluminum/silver sheets.In the cold roll bonding process,after brushing and acid washing,the pre...This article examines the influence of annealing temperature on fracture toughness and forming limit curves of dissimilar aluminum/silver sheets.In the cold roll bonding process,after brushing and acid washing,the prepared surfaces are placed on top of each other and by rolling with reduction more than 50%,the bonding between layers is established.In this research,the roll bonding process was done at room temperature,without the use of lubricants and with a 70%thickness reduction.Then,the final thickness of the Ag/Al bilayer sheet reached 350μm by several stages of cold rolling.Before cold rolling,it should be noted that to decrease the hardness created due to plastic deformation,the roll-bonded samples were subjected to annealing heat treatment at 400℃for 90 min.Thus,the final samples were annealed at 200,300 and 400℃for 90 min and cooled in a furnace to examine the annealing temperature effects.The uniaxial tensile and microhardness tests measured mechanical properties.Also,to investigate the fracture mechanism,the fractography of the cross-section was examined by scanning electron microscope(SEM).To evaluate the formability of Ag/Al bilayer sheets,forming limit curves were obtained experimentally through the Nakazima test.The resistance of composites to failure due to cracking was also investigated by fracture toughness.The results showed that annealing increases the elongation and formability of the Ag/Al bilayer sheet while reduces the ultimate tensile strength and fracture toughness.However,the changing trend is not the same at different temperatures,and according to the results,the most significant effect is obtained at 300℃and aluminum layers.It was also determined that by increasing annealing temperature,the fracture mechanism from shear ductile with small and shallow dimples becomes ductile with deep cavities.展开更多
Silicon limitation negatively affects the growth and metabolism of diatoms.However,its influence on the topography and mechanical properties of diatom frustules,and consequently on predation,remains unclear.We investi...Silicon limitation negatively affects the growth and metabolism of diatoms.However,its influence on the topography and mechanical properties of diatom frustules,and consequently on predation,remains unclear.We investigated how silicon limitation affects the mechanical strength of diatom frustules.Under silicon limitation,the growth rates of diatom Cylindrotheca closterium,Amphora coffeaeformis,Thalassiosira weissflogii,and Cyclotella sp.decreased by 19%,56%,42%,and 73%,respectively.Similarly,the biogenic silica content of silicon-limited C.closterium,T.weissflogii,and Cyclotella sp.decreased by 17%,11%,and 9%,respectively,whereas A.coffeaeformis showed a 63%increase.Atomic force microscopy and X-ray photoelectron spectroscopy revealed that silicon shortage reduced frustule hardness by approximately 60%and decreased condensed silica components on their surface by about 80%,except in A.coffeaeformis.Additionally,copepods consumed 20%to 600%more diatoms grown under silicon deficiency compared to those grown under Si-rich conditions,with the exception of A.coffeaeformis.These findings suggest that silicon limitation diminishes diatom populations and accelerates carbon export from diatoms to the deep sea.展开更多
As a new dynamic reactive power compensator,the grid-forming Static Var Generator(GF-SVG)can not only provide reactive power-voltage support,but also has inertial support capability.It has been experimentally deployed...As a new dynamic reactive power compensator,the grid-forming Static Var Generator(GF-SVG)can not only provide reactive power-voltage support,but also has inertial support capability.It has been experimentally deployed in many wind farms.However,studies have shown that when the three-phase short-circuit fault occurs in the wind farm,the transient overcurrent during the fault occurrence and fault clearance is suppressed,making it difficult for GF-SVG to use traditional fixed virtual impedance.Aiming at the problem,firstly,the influence of virtual reactance on control stability is analyzed using the GF-SVG’s current open-loop transfer function.Secondly,based on the existing current limitation strategies of GF-SVG,an adaptive virtual reactance current limitation strategy suitable for symmetrical faults of the power grid is proposed,which limits GF-SVG’s transient overcurrent during fault occurrence and fault clearance stage to the tolerance range of GF-SVG’s power devices.Based on the GF-SVG’s active power loop and reactive power loop small signal models,the availability of the proposed adaptive virtual reactance in suppressing the DC voltage drop of GF-SVG is analyzed,and shortening the transient overvoltage recovery time of the wind farm after the fault clearance is also discussed.Finally,electromagnetic simulation proves the effectiveness and correctness of the proposed adaptive current limitation method.展开更多
Commonly,the standards for the geometric design of roads refer to a given set of values for the friction coefficient(longitudinal and transverse friction).These"reference"values imply corresponding visibilit...Commonly,the standards for the geometric design of roads refer to a given set of values for the friction coefficient(longitudinal and transverse friction).These"reference"values imply corresponding visibility sights,curvature radii,and speed limits.Unfortunately,not only do these reference values not correspond to a given standard to measure them,but nothing is said about the decrease of the posted speed limit(variable speed limits)when roads become slippery and lanes for autonomous vehicle(AV)are concerned.Furthermore,the same assessment of the friction coefficient has plenty of uncertainties due to measurement device,temperature,location,time passed from the construction,alignment-related variables(e.g.,curve,tangent,transition curve,convexity/crests or concavity/sags,longitudinal slope,superelevation,and ruling gradient),and supplementary singularities such as joints and bridge approaches.All the issues above may harm road safety and the complexity of forensic investigations of pavements.Consequently,this study's objectives were confined to(1)carrying out friction measurements and analyzing the problem of friction decay over time;(2)setting up a method to lower the speed limits where friction decays are detected;(3)setting up a method to handle friction decays for autonomous vehicles.Results demonstrate that:(1)a power law describes how the speed limits are affected by friction;(2)for speeds up to 170 km/h,due to the lower reaction time,AV reaction distance is lower,which benefits AV traffic(lower stopping distance);(3)on the contrary,for higher values of friction and higher speeds,under the hypothesis of having the same reaction time law for non-AV(NAV)(i.e.,decreasing with the initial speed),AV speed limits become lower than NAV speed limits;(4)not only do comfort-based speed profiles for AVs bring higher braking distances,but also,in the median part(of the deceleration process),this could pose safety issues and reduce the distance between the available and the needed friction.展开更多
On July 24th, Lectra's Board of Directors, chaired by Daniel Harari, reviewed the consolidated financial statements for the first half of 2025, which have been subject to a limited review by the Statutory Auditors.
Two-dimensional perovskite ferroelectric which strongly couple ferroelectricity with semiconducting properties are promising candidates for optoelectronic applications.However,it is still a great challenge to fabricat...Two-dimensional perovskite ferroelectric which strongly couple ferroelectricity with semiconducting properties are promising candidates for optoelectronic applications.However,it is still a great challenge to fabricate self-powered broadband photodetectors with low detection limit.Herein,we successfully realized self-powered broadband photodetection with low detection limit by using a trilayered perovskite ferroelectric(BA)_(2)EA_(2)Pb_(3)I_(10)(1,BA=n-butylamine,EA=ethylamine).Giving to its large spontaneous polarization(5.6μC/cm^(2)),1 exhibits an open-circuit voltage of 0.25 V which provide driving force to separate carriers.Combining with its low dark current(~10^(-14)A)and narrow bandgap(Eg=1.86 e V),1 demonstrates great potential on detecting the broadband weak lights.Thus,a prominent photodetection performance with high open-off ratio(~10^(5)),outstanding responsivity(>10 m A/W),and promising detectivity(>1011Jones),as well as the low detecting limit(~nW/cm^(2))among the wide wavelength from 377 nm to637 nm was realized based on the single crystal of 1.This work demonstrates the great potential of 2D perovskite ferroelectric on self-powered broadband photodetectors.展开更多
Optical monitoring of object position and alignment with nanoscale precision is critical for ultra-precision measurement applications,such as micro/nano-fabrication,weak force sensing,and micro-scopic imaging.Traditio...Optical monitoring of object position and alignment with nanoscale precision is critical for ultra-precision measurement applications,such as micro/nano-fabrication,weak force sensing,and micro-scopic imaging.Traditional optical nanometry methods often rely on precision nanostructure fabrication,multi-beam interferometry,or complex post-processing algorithms,which can limit their practical use.In this study,we introduced a simplified and robust quantum measurement technique with an achievable resolution of 2.2 pm and an experimental demonstration of 1 nm resolution,distinguishing it from conventional interferometry,which depended on multiple reference beams.We designed a metasurface substrate with a mode-conversion function,in which an incident Gaussian beam is converted into higher-order transverse electromagnetic mode(TEM)modes.A theoretical analysis,including calculations of the Fisher information,demonstrated that the accuracy was maintained for nanoscale displacements.In conclusion,the study findings provide a new approach for precise alignment and metrology of nanofabrication and other advanced applications.展开更多
Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of ro...Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of rock mass rating(RMR).Considering a low-grade metal mine as an example,this study exploited geostatistical methods to obtain independent RMR for each block unit.A three-dimensional spatial distribution model for the powder factor was developed on the basis of the relationships between the RMR and the powder factor.Subsequently,models for blasting cost and mining value were built and employed to optimize the open-pit limit.The multi-variable model based on the RMR performed well in predicting the powder factor,achieving a correlation coefficient of 0.88(root mean square error of 4.3)and considerably outperforming the uniaxial compressive strength model.After model optimization,the mean size and standard deviation of the fragments in the blast pile decreased by 8.5%and 35.1%,respectively,whereas the boulder yield and its standard deviation decreased by 33.3%and 58.8%,respectively.Additionally,optimizing the open-pit limit using this method reduced the amount of rock,increased the amount of ore,and lowered blasting costs,thereby enhancing the economic efficiency of the mine.This study provides valuable insights for blasting design and mining decisions,demonstrating the advantages and potential applications of powder factor prediction based on the heterogeneity of rock mass quality.展开更多
Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FML...Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FMLs possess complex interlayer stresses and low forming limits,restricting further promotion and application of FMLs.Low-constraint FMLs exhibit a lower forming resistance and better formability due to no curing during the forming process;however,the formation mechanism and response are not clear.This paper presents the Forming Limit Diagram(FLD)of low-constraint GLARE(glass fiber reinforced aluminum laminates)based on the forming limit test,and compares it with the conventionally cured laminates to evaluate the differences in the forming limit.In addition,combined with the analysis of failure mechanism and micro-deformation mechanism of specimens,the influence of different temperatures(20–80℃)and forming states(width)on the deformation performance of laminates is further explored.The results reveal that the forming limit curve of low-constraint laminates shifts up with the increase of temperature,the forming limit initially increases with the increase of width,then followed by a gradual decrease,and the maximum principal strain of low-constraint laminates is increased by 29% at 80℃ compared to 20℃.The cured laminate has a principal strain range of 0–0.02,while the low-constraint laminates have a principal strain range of 0.03–0.14.Compared with cured laminates,low-constraint laminates possess a higher forming limit due to the improvement in deformable degree between layers by resin flow and fiber slippage,which enhances their formability.This study is expected to serve as a reference for establishing forming limit criteria and optimizing forming schemes for low-constraint laminates.展开更多
Tibetan alpine steppes are large and sensitive terrestrial carbon(C)reservoirs that are experiencing desertification due to global change and overgrazing,which can lead to stronger resource limitations for both above-...Tibetan alpine steppes are large and sensitive terrestrial carbon(C)reservoirs that are experiencing desertification due to global change and overgrazing,which can lead to stronger resource limitations for both above-and belowground communities.Soil nutrients,especially nitrogen(N)and phosphorus(P),are the crucial resources for plant growth and microbial metabolism.However,whether both plant and soil microbial communities in the degraded alpine steppes are limited by these soil nutrients remains unclear,which limits our understanding of the mechanisms of desertification and subsequent ecosystem restoration.Here,we evaluated potential nutrient limitations of the plant and soil microbial communities in the alpine steppe across five stages of desertification using stoichiometry-based approaches.Our results showed that soil microbial metabolism was mainly limited by C and P,and the plant N limitation and microbial C limitation were intensified while the microbial P limitation was relieved during desertification.Plant-soil-microbe interactions had significant impacts on the microbial C and P limitations,explaining 72 and 61%of the variation,respectively.Specifically,desertification ultimately affected microbial metabolic limitations by regulating soil pH,soil nutrients,and the plant N limitation.Moreover,the microbial C limitation further reduced microbial C use efficiency(CUE)with desertification,which is detrimental for organic C retention in the degraded soil.Overall,this study revealed that microbial metabolic limitations through plant-microbe interactions were the key drivers affecting soil microbial CUE,and it provided insights that can advance our knowledge of the microbial regulation of nutrient cycles and C sequestration.展开更多
Point-of-care ultrasound(POCUS) is recognized as a valuable diagnostic tool,especially in resourcelimited settings(RLS).POCUS provides rapid diagnostic information that enables health professionals to make critical de...Point-of-care ultrasound(POCUS) is recognized as a valuable diagnostic tool,especially in resourcelimited settings(RLS).POCUS provides rapid diagnostic information that enables health professionals to make critical decisions at the bedside.^([1]) Despite the welldocumented benefits of POCUS,access to longitudinal,comprehensive training programs and a lack of trainee feedback are barriers to the widespread use of this technology in such settings.^([2])展开更多
The increasing occurrence of sinkholes caused by water main bursts has attracted significant research attention in recent years.This study addresses the gap in evaluating soil blowout stability resulting from water ma...The increasing occurrence of sinkholes caused by water main bursts has attracted significant research attention in recent years.This study addresses the gap in evaluating soil blowout stability resulting from water main failures by investigating the three-dimensional stability of blowouts with circular,hemispherical,and spherical openings.Advanced finite element limit analysis(FELA)combined with adaptive meshing is employed to analyze critical factors,including soil cover depth,surcharge pressure,and internal water pressure,that contribute to blowout failure.In addition,dimensionless ratios are used throughout the paper to assess the influence of these factors.Numerical findings are rigorously validated,ensuring reliability and accuracy.Practical design charts are provided to accommodate a wide range of design scenarios,offering valuable guidance for engineers.This study introduces a pioneering sinkhole simulation methodology,leading to the understanding of three-dimensional blowout stability mechanisms.展开更多
Agricultural land development is a pivotal strategy for addressing the global food security crisis.Barren grassland,especially those in mountainous regions,constitutes critical areas where cultivation can substantiall...Agricultural land development is a pivotal strategy for addressing the global food security crisis.Barren grassland,especially those in mountainous regions,constitutes critical areas where cultivation can substantially enhance land resources.This study highlights the necessity for a precise correlation between land development initiatives and constraints in order to optimize efficiency and enhance the effectiveness of such projects,with the core being the seamless integration of land development engineering and techniques to eliminate agricultural constraints.This study employs a systems engineering approach to classify improvement factors into mobile and fixed categories,elucidating the integration methods of constraint factors.Adhering to the Wooden Barrel Principle,these constraints were rigorously analyzed based on soil quality,land topography,water availability,and agricultural infrastructure.An innovative method of engineering type combination is proposed,which effectively explains the correlation between natural factors combination,project type combination,and target factors combination.It provides a convenient way for the selection of barren grassland development projects and lays a foundation for land planning,development project establishment,program selection,engineering design,and budget preparation.Taking Tang County of China as an example,it is divided into 19 factor improvement areas,a quick reference table of engineering types is established,and 14 main types of engineering combinations are obtained,which lays a foundation for the application of theoretical framework in practice.展开更多
Predictive control(PC)is an advanced control algorithm,which is widely used in industrial process control.Among them,model-based predictive control(MPC)is an important branch of predictive control.Its basic principle ...Predictive control(PC)is an advanced control algorithm,which is widely used in industrial process control.Among them,model-based predictive control(MPC)is an important branch of predictive control.Its basic principle is to use the system model to predict future behavior and determine the current control action by optimizing the objective function.Based on the algorithm combined with three different sections using deep learning technology to identify vehicles and output the optimal speed limit,to achieve the effect of traffic flow optimization.展开更多
The shop scheduling problem with limited buffers has broad applications in real-world production scenarios,so this research direction is of great practical significance.However,there is currently little research on th...The shop scheduling problem with limited buffers has broad applications in real-world production scenarios,so this research direction is of great practical significance.However,there is currently little research on the hybrid flow shop scheduling problem with limited buffers(LBHFSP).This paper deeply investigates the LBHFSP to optimize the goal of the total completion time.To better solve the LBHFSP,a multi-level subpopulation-based particle swarm optimization algorithm(MLPSO)is proposed,which is founded on the attributes of the LBHFSP and the shortcomings of the basic PSO(particle swarm optimization)algorithm.In MLPSO,firstly,considering the impact of the limited buffers on the process of subsequent operations,a specific circular decoding strategy is developed to accommodate the characteristics of limited buffers.Secondly,an initialization strategy based on blocking time is designed to enhance the quality and diversity of the initial population.Afterward,a multi-level subpopulation collaborative search is developed to prevent being trapped in a local optimum and improve the global exploration capability.Additionally,a local search strategy based on the first blocked job is designed to enhance the MLPSO algorithm’s exploitation capability.Lastly,numerous experiments are carried out to test the performance of the proposed MLPSO by comparing it with classical intelligent optimization and popular algorithms in recent years.The results confirm that the proposed MLPSO has an outstanding performance when compared to other algorithms when solving LBHFSP.展开更多
Hydraulic fracturing and commingle production of multiple layers are extensively adopted in unconventional tight gas reservoirs.Accurate determination of parameters of individual layers in multilayered tight gas reser...Hydraulic fracturing and commingle production of multiple layers are extensively adopted in unconventional tight gas reservoirs.Accurate determination of parameters of individual layers in multilayered tight gas reservoirs is essential for well performance evaluation and development strategy optimization.However,most analytical models for fractured vertical wells in stratified gas reservoirs focus on fully penetrated hydraulic fractures,neglecting the influence of partial penetration of hydraulic fractures.This paper presents a semi-analytical model to investigate the transient pressure behavior of vertically fractured wells in dual porosity multi-layered tight gas reservoirs.The partial penetration of hydraulic fracture,the vertical heterogeneities of layer properties,the differences between hydraulic fracture lengths in each layer and the stress sensitivity are all incorporated in the proposed model.The point-source solution,Laplace transformation,Fourier transformation,Pedrosa's transformation,perturbation technique,and the superposition principle are applied to obtain the analytical solution of transient pressure responses.The proposed model is validated against a commercial software,and the transient pressure behavior of vertically fractured wells in multi-layered tight gas reservoirs are analyzed.Based on the characteristics of the type curves,seven flow regimes can be identified,including wellbore storage,transitional flow period,reservoir linear flow period,vertical pseudo-radial flow in fracture system,inter-porosity flow period,late-time pseudo-radial flow period,and the boundary-dominated flow period.Sensitivity analyses reveal that the penetration ratio of hydraulic fracture has primary influence on early-time transient pressure behavior and production contribution,while the stress sensitivity mainly affects the late-time transient pressure behavior.Gas production at the initial stage is mainly contributed by the high-pressure/high-permeability layer,and gas backflow will occur during initial production stage for obviously unequal initial formation pressures.Finally,two field cases are conducted to illustrate the applicability of the proposed model.The model and corresponding conclusions can provide technical support for performance analysis of tight gas reservoirs.展开更多
AIM:To find the effective contrast enhancement method on retinal images for effective segmentation of retinal features.METHODS:A novel image preprocessing method that used neighbourhood-based improved contrast limited...AIM:To find the effective contrast enhancement method on retinal images for effective segmentation of retinal features.METHODS:A novel image preprocessing method that used neighbourhood-based improved contrast limited adaptive histogram equalization(NICLAHE)to improve retinal image contrast was suggested to aid in the accurate identification of retinal disorders and improve the visibility of fine retinal structures.Additionally,a minimal-order filter was applied to effectively denoise the images without compromising important retinal structures.The novel NICLAHE algorithm was inspired by the classical CLAHE algorithm,but enhanced it by selecting the clip limits and tile sized in a dynamical manner relative to the pixel values in an image as opposed to using fixed values.It was evaluated on the Drive and high-resolution fundus(HRF)datasets on conventional quality measures.RESULTS:The new proposed preprocessing technique was applied to two retinal image databases,Drive and HRF,with four quality metrics being,root mean square error(RMSE),peak signal to noise ratio(PSNR),root mean square contrast(RMSC),and overall contrast.The technique performed superiorly on both the data sets as compared to the traditional enhancement methods.In order to assess the compatibility of the method with automated diagnosis,a deep learning framework named ResNet was applied in the segmentation of retinal blood vessels.Sensitivity,specificity,precision and accuracy were used to analyse the performance.NICLAHE–enhanced images outperformed the traditional techniques on both the datasets with improved accuracy.CONCLUSION:NICLAHE provides better results than traditional methods with less error and improved contrastrelated values.These enhanced images are subsequently measured by sensitivity,specificity,precision,and accuracy,which yield a better result in both datasets.展开更多
基金supported by the National Key Research and Development Plan Project Sub-Topic of China(Grant Nos.2022YFD1901500 and 2022YFD1901505-07)the National Natural Science Foundation of China(Grant No.32260531)+1 种基金the Key Laboratory of Molecular Breeding for Grain and Oil Crops in Guizhou Province,China(Grant No.Qiankehezhongyindi[2023]8)the Key Laboratory of Functional Agriculture of Guizhou Provincial Higher Education Institutions,China(Grant No.Qianjiaoji[2023]007).
文摘Recently,information acquired at the canopy top,such as spectral and textural data,has been widely used to estimate plant nitrogen(N)accumulation(PNA).The response of crops to N uptake involves not only changes in horizontal canopy top information but also an increase in vertical plant height(PH).It remains unclear whether the fusion of spectral indices with PH can improve the estimation performance of PNA models based on spectral remote sensing across different growth stages.
文摘In this paper,a nonlinear control approach for an unstable networked plant in the presence of actuator and sensor limitations using robust right coprime factorization is proposed.The actuator is limited by upper and lower constraints and the sensor in the feedback loop is subjected to network-induced unknown time-varying delay and noise.With this nonlinear control method,we first employ right coprime factorization based on isomorphism and operator theory to factorize the plant,so that bounded input bounded output(BIBO)stability can be guaranteed.Next,continuous-time generalized predictive control(CGPC)is utilized for the unstable operator of the right coprime factorized plant to guarantee inner stability and enables the closed-loop dynamics of the system with predictive characteristics.Meanwhile,a second-Do F(degrees of freedom)switched controller that satisfies a perturbed Bezout identity and a robustness condition is designed.By using the CGPC controller that possesses predictive behavior and the second-Do F switched stabilizer,the overall stability of the plant subjected to actuator limitations is guaranteed.To address sensor limitations that exist in networked plants in the form of delay and noise which often cause system performance degradation,we implement an identity operator definition in the feedback loop to compensate for these adverse effects.Further,a pre-operator is designed to ensure that the plant output tracks the reference input.Finally,the effectiveness of the proposed design scheme is demonstrated by simulations.
文摘Objective:To evaluate the effectiveness of the internal limiting membrane(ILM)flipping and covering technique in the treatment of patients with high myopic macular hole(HMMH).Methods:One hundred and two patients with HMMH who were admitted to the hospital from June 2019 to June 2024 were selected.The minimum diameter of the macular hole(MH)in all patients was≤500μm.The patients were randomly divided into two groups.The experimental group received 25G pars plana vitrectomy(PPV)combined with ILM flipping and covering technique,while the reference group received PPV combined with ILM peeling.The efficacy indicators and best corrected visual acuity levels were compared between the two groups.Results:The MH closure rate and retinal reattachment rate were higher in the experimental group than in the reference group at 3 and 6 months postoperatively(P<0.05).The best corrected visual acuity level was higher in the experimental group than in the reference group at 3 and 6 months postoperatively(P<0.05).The Chinese version of the Visual Function-Related Quality of Life Questionnaire-25(CVRQOL-25)score was higher in the experimental group than in the reference group at 3 and 6 months postoperatively(P<0.05).No serious complications were observed in both groups postoperatively,and there was no difference between the two groups(P>0.05).Conclusion:The ILM flipping and covering technique can improve the MH closure rate and retinal reattachment rate in patients with HMMH(diameter≤500μm),enhance the best corrected visual acuity level,and improve the quality of life related to visual function,with fewer postoperative complications.
基金Project(4013311)supported by the National Science Foundation of Iran(INSF)。
文摘This article examines the influence of annealing temperature on fracture toughness and forming limit curves of dissimilar aluminum/silver sheets.In the cold roll bonding process,after brushing and acid washing,the prepared surfaces are placed on top of each other and by rolling with reduction more than 50%,the bonding between layers is established.In this research,the roll bonding process was done at room temperature,without the use of lubricants and with a 70%thickness reduction.Then,the final thickness of the Ag/Al bilayer sheet reached 350μm by several stages of cold rolling.Before cold rolling,it should be noted that to decrease the hardness created due to plastic deformation,the roll-bonded samples were subjected to annealing heat treatment at 400℃for 90 min.Thus,the final samples were annealed at 200,300 and 400℃for 90 min and cooled in a furnace to examine the annealing temperature effects.The uniaxial tensile and microhardness tests measured mechanical properties.Also,to investigate the fracture mechanism,the fractography of the cross-section was examined by scanning electron microscope(SEM).To evaluate the formability of Ag/Al bilayer sheets,forming limit curves were obtained experimentally through the Nakazima test.The resistance of composites to failure due to cracking was also investigated by fracture toughness.The results showed that annealing increases the elongation and formability of the Ag/Al bilayer sheet while reduces the ultimate tensile strength and fracture toughness.However,the changing trend is not the same at different temperatures,and according to the results,the most significant effect is obtained at 300℃and aluminum layers.It was also determined that by increasing annealing temperature,the fracture mechanism from shear ductile with small and shallow dimples becomes ductile with deep cavities.
基金Supported by the National Natural Science Foundation of China(Nos.U 23 A 2048,42376152,42076148)the Special Program of Key Sectors in Guangdong Universities(Nos.2022 ZDZX 4040,2023 KCXTD 028)。
文摘Silicon limitation negatively affects the growth and metabolism of diatoms.However,its influence on the topography and mechanical properties of diatom frustules,and consequently on predation,remains unclear.We investigated how silicon limitation affects the mechanical strength of diatom frustules.Under silicon limitation,the growth rates of diatom Cylindrotheca closterium,Amphora coffeaeformis,Thalassiosira weissflogii,and Cyclotella sp.decreased by 19%,56%,42%,and 73%,respectively.Similarly,the biogenic silica content of silicon-limited C.closterium,T.weissflogii,and Cyclotella sp.decreased by 17%,11%,and 9%,respectively,whereas A.coffeaeformis showed a 63%increase.Atomic force microscopy and X-ray photoelectron spectroscopy revealed that silicon shortage reduced frustule hardness by approximately 60%and decreased condensed silica components on their surface by about 80%,except in A.coffeaeformis.Additionally,copepods consumed 20%to 600%more diatoms grown under silicon deficiency compared to those grown under Si-rich conditions,with the exception of A.coffeaeformis.These findings suggest that silicon limitation diminishes diatom populations and accelerates carbon export from diatoms to the deep sea.
基金supported by the National Natural Science Foundation of China under Grant 52077030.
文摘As a new dynamic reactive power compensator,the grid-forming Static Var Generator(GF-SVG)can not only provide reactive power-voltage support,but also has inertial support capability.It has been experimentally deployed in many wind farms.However,studies have shown that when the three-phase short-circuit fault occurs in the wind farm,the transient overcurrent during the fault occurrence and fault clearance is suppressed,making it difficult for GF-SVG to use traditional fixed virtual impedance.Aiming at the problem,firstly,the influence of virtual reactance on control stability is analyzed using the GF-SVG’s current open-loop transfer function.Secondly,based on the existing current limitation strategies of GF-SVG,an adaptive virtual reactance current limitation strategy suitable for symmetrical faults of the power grid is proposed,which limits GF-SVG’s transient overcurrent during fault occurrence and fault clearance stage to the tolerance range of GF-SVG’s power devices.Based on the GF-SVG’s active power loop and reactive power loop small signal models,the availability of the proposed adaptive virtual reactance in suppressing the DC voltage drop of GF-SVG is analyzed,and shortening the transient overvoltage recovery time of the wind farm after the fault clearance is also discussed.Finally,electromagnetic simulation proves the effectiveness and correctness of the proposed adaptive current limitation method.
文摘Commonly,the standards for the geometric design of roads refer to a given set of values for the friction coefficient(longitudinal and transverse friction).These"reference"values imply corresponding visibility sights,curvature radii,and speed limits.Unfortunately,not only do these reference values not correspond to a given standard to measure them,but nothing is said about the decrease of the posted speed limit(variable speed limits)when roads become slippery and lanes for autonomous vehicle(AV)are concerned.Furthermore,the same assessment of the friction coefficient has plenty of uncertainties due to measurement device,temperature,location,time passed from the construction,alignment-related variables(e.g.,curve,tangent,transition curve,convexity/crests or concavity/sags,longitudinal slope,superelevation,and ruling gradient),and supplementary singularities such as joints and bridge approaches.All the issues above may harm road safety and the complexity of forensic investigations of pavements.Consequently,this study's objectives were confined to(1)carrying out friction measurements and analyzing the problem of friction decay over time;(2)setting up a method to lower the speed limits where friction decays are detected;(3)setting up a method to handle friction decays for autonomous vehicles.Results demonstrate that:(1)a power law describes how the speed limits are affected by friction;(2)for speeds up to 170 km/h,due to the lower reaction time,AV reaction distance is lower,which benefits AV traffic(lower stopping distance);(3)on the contrary,for higher values of friction and higher speeds,under the hypothesis of having the same reaction time law for non-AV(NAV)(i.e.,decreasing with the initial speed),AV speed limits become lower than NAV speed limits;(4)not only do comfort-based speed profiles for AVs bring higher braking distances,but also,in the median part(of the deceleration process),this could pose safety issues and reduce the distance between the available and the needed friction.
文摘On July 24th, Lectra's Board of Directors, chaired by Daniel Harari, reviewed the consolidated financial statements for the first half of 2025, which have been subject to a limited review by the Statutory Auditors.
基金financially supported by the National Natural Science Foundation of China(Nos.22435005,22193042,21921001,22305105,52202194,22201284)Natural Science Foundation of Jiangxi Province(No.20224BAB213003)+1 种基金the Natural Science Foundation of Fujian Province(No.2023J05076)Jiangxi Provincial Education Department Science and Technology Research Foundation(No.GJJ2200384)。
文摘Two-dimensional perovskite ferroelectric which strongly couple ferroelectricity with semiconducting properties are promising candidates for optoelectronic applications.However,it is still a great challenge to fabricate self-powered broadband photodetectors with low detection limit.Herein,we successfully realized self-powered broadband photodetection with low detection limit by using a trilayered perovskite ferroelectric(BA)_(2)EA_(2)Pb_(3)I_(10)(1,BA=n-butylamine,EA=ethylamine).Giving to its large spontaneous polarization(5.6μC/cm^(2)),1 exhibits an open-circuit voltage of 0.25 V which provide driving force to separate carriers.Combining with its low dark current(~10^(-14)A)and narrow bandgap(Eg=1.86 e V),1 demonstrates great potential on detecting the broadband weak lights.Thus,a prominent photodetection performance with high open-off ratio(~10^(5)),outstanding responsivity(>10 m A/W),and promising detectivity(>1011Jones),as well as the low detecting limit(~nW/cm^(2))among the wide wavelength from 377 nm to637 nm was realized based on the single crystal of 1.This work demonstrates the great potential of 2D perovskite ferroelectric on self-powered broadband photodetectors.
基金supported by the West Light Project,CAS(xbzg-zdsys-202206)the National Key Research and Development Program of China(2021YFA1401003)+1 种基金the National Natural Science Foundation of China(NSFC)(62222513,U24A6010,and U24A20317)the Sichuan Engineering Research Center of Digital Materials.
文摘Optical monitoring of object position and alignment with nanoscale precision is critical for ultra-precision measurement applications,such as micro/nano-fabrication,weak force sensing,and micro-scopic imaging.Traditional optical nanometry methods often rely on precision nanostructure fabrication,multi-beam interferometry,or complex post-processing algorithms,which can limit their practical use.In this study,we introduced a simplified and robust quantum measurement technique with an achievable resolution of 2.2 pm and an experimental demonstration of 1 nm resolution,distinguishing it from conventional interferometry,which depended on multiple reference beams.We designed a metasurface substrate with a mode-conversion function,in which an incident Gaussian beam is converted into higher-order transverse electromagnetic mode(TEM)modes.A theoretical analysis,including calculations of the Fisher information,demonstrated that the accuracy was maintained for nanoscale displacements.In conclusion,the study findings provide a new approach for precise alignment and metrology of nanofabrication and other advanced applications.
基金supported by the National Key Research and Development Program of China(No.2022YFC2903902)the National Natural Science Foundation of China(Nos.52204080and 52174070)the Fundamental Research Funds for the Central Universities of China(No.2023GFYD17)。
文摘Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of rock mass rating(RMR).Considering a low-grade metal mine as an example,this study exploited geostatistical methods to obtain independent RMR for each block unit.A three-dimensional spatial distribution model for the powder factor was developed on the basis of the relationships between the RMR and the powder factor.Subsequently,models for blasting cost and mining value were built and employed to optimize the open-pit limit.The multi-variable model based on the RMR performed well in predicting the powder factor,achieving a correlation coefficient of 0.88(root mean square error of 4.3)and considerably outperforming the uniaxial compressive strength model.After model optimization,the mean size and standard deviation of the fragments in the blast pile decreased by 8.5%and 35.1%,respectively,whereas the boulder yield and its standard deviation decreased by 33.3%and 58.8%,respectively.Additionally,optimizing the open-pit limit using this method reduced the amount of rock,increased the amount of ore,and lowered blasting costs,thereby enhancing the economic efficiency of the mine.This study provides valuable insights for blasting design and mining decisions,demonstrating the advantages and potential applications of powder factor prediction based on the heterogeneity of rock mass quality.
基金supported by the National Natural Science Fund of China(Nos.52005153,12227801,32300666,12072005,U23A2607)the Tianjin"Project+Team"Key Training Program,China(No.XC202052)+4 种基金the Key Program of Research and Development of Hebei Province,China(Nos.202030507040009,23311812D)the Natural Science Foundation of Hebei Province,China(No.E2023202183)the Project of High-Level Team Construction Introduction of Hebei Province,China(No.244A7620D)the Research Cooperation Project of Universities Stationed in Hebei Province and Shijiazhuang City,China(No.241080114A)Hebei Province Military-Civilian Integration Science and Technology Innovation Project,China(No.SJMYF2022X15)。
文摘Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FMLs possess complex interlayer stresses and low forming limits,restricting further promotion and application of FMLs.Low-constraint FMLs exhibit a lower forming resistance and better formability due to no curing during the forming process;however,the formation mechanism and response are not clear.This paper presents the Forming Limit Diagram(FLD)of low-constraint GLARE(glass fiber reinforced aluminum laminates)based on the forming limit test,and compares it with the conventionally cured laminates to evaluate the differences in the forming limit.In addition,combined with the analysis of failure mechanism and micro-deformation mechanism of specimens,the influence of different temperatures(20–80℃)and forming states(width)on the deformation performance of laminates is further explored.The results reveal that the forming limit curve of low-constraint laminates shifts up with the increase of temperature,the forming limit initially increases with the increase of width,then followed by a gradual decrease,and the maximum principal strain of low-constraint laminates is increased by 29% at 80℃ compared to 20℃.The cured laminate has a principal strain range of 0–0.02,while the low-constraint laminates have a principal strain range of 0.03–0.14.Compared with cured laminates,low-constraint laminates possess a higher forming limit due to the improvement in deformable degree between layers by resin flow and fiber slippage,which enhances their formability.This study is expected to serve as a reference for establishing forming limit criteria and optimizing forming schemes for low-constraint laminates.
基金supported by the National Key Research and Development Program of China(2023YFF1304304)。
文摘Tibetan alpine steppes are large and sensitive terrestrial carbon(C)reservoirs that are experiencing desertification due to global change and overgrazing,which can lead to stronger resource limitations for both above-and belowground communities.Soil nutrients,especially nitrogen(N)and phosphorus(P),are the crucial resources for plant growth and microbial metabolism.However,whether both plant and soil microbial communities in the degraded alpine steppes are limited by these soil nutrients remains unclear,which limits our understanding of the mechanisms of desertification and subsequent ecosystem restoration.Here,we evaluated potential nutrient limitations of the plant and soil microbial communities in the alpine steppe across five stages of desertification using stoichiometry-based approaches.Our results showed that soil microbial metabolism was mainly limited by C and P,and the plant N limitation and microbial C limitation were intensified while the microbial P limitation was relieved during desertification.Plant-soil-microbe interactions had significant impacts on the microbial C and P limitations,explaining 72 and 61%of the variation,respectively.Specifically,desertification ultimately affected microbial metabolic limitations by regulating soil pH,soil nutrients,and the plant N limitation.Moreover,the microbial C limitation further reduced microbial C use efficiency(CUE)with desertification,which is detrimental for organic C retention in the degraded soil.Overall,this study revealed that microbial metabolic limitations through plant-microbe interactions were the key drivers affecting soil microbial CUE,and it provided insights that can advance our knowledge of the microbial regulation of nutrient cycles and C sequestration.
文摘Point-of-care ultrasound(POCUS) is recognized as a valuable diagnostic tool,especially in resourcelimited settings(RLS).POCUS provides rapid diagnostic information that enables health professionals to make critical decisions at the bedside.^([1]) Despite the welldocumented benefits of POCUS,access to longitudinal,comprehensive training programs and a lack of trainee feedback are barriers to the widespread use of this technology in such settings.^([2])
文摘The increasing occurrence of sinkholes caused by water main bursts has attracted significant research attention in recent years.This study addresses the gap in evaluating soil blowout stability resulting from water main failures by investigating the three-dimensional stability of blowouts with circular,hemispherical,and spherical openings.Advanced finite element limit analysis(FELA)combined with adaptive meshing is employed to analyze critical factors,including soil cover depth,surcharge pressure,and internal water pressure,that contribute to blowout failure.In addition,dimensionless ratios are used throughout the paper to assess the influence of these factors.Numerical findings are rigorously validated,ensuring reliability and accuracy.Practical design charts are provided to accommodate a wide range of design scenarios,offering valuable guidance for engineers.This study introduces a pioneering sinkhole simulation methodology,leading to the understanding of three-dimensional blowout stability mechanisms.
基金funded by Science and Technology Project of Hebei Education Department[QN2023085].
文摘Agricultural land development is a pivotal strategy for addressing the global food security crisis.Barren grassland,especially those in mountainous regions,constitutes critical areas where cultivation can substantially enhance land resources.This study highlights the necessity for a precise correlation between land development initiatives and constraints in order to optimize efficiency and enhance the effectiveness of such projects,with the core being the seamless integration of land development engineering and techniques to eliminate agricultural constraints.This study employs a systems engineering approach to classify improvement factors into mobile and fixed categories,elucidating the integration methods of constraint factors.Adhering to the Wooden Barrel Principle,these constraints were rigorously analyzed based on soil quality,land topography,water availability,and agricultural infrastructure.An innovative method of engineering type combination is proposed,which effectively explains the correlation between natural factors combination,project type combination,and target factors combination.It provides a convenient way for the selection of barren grassland development projects and lays a foundation for land planning,development project establishment,program selection,engineering design,and budget preparation.Taking Tang County of China as an example,it is divided into 19 factor improvement areas,a quick reference table of engineering types is established,and 14 main types of engineering combinations are obtained,which lays a foundation for the application of theoretical framework in practice.
文摘Predictive control(PC)is an advanced control algorithm,which is widely used in industrial process control.Among them,model-based predictive control(MPC)is an important branch of predictive control.Its basic principle is to use the system model to predict future behavior and determine the current control action by optimizing the objective function.Based on the algorithm combined with three different sections using deep learning technology to identify vehicles and output the optimal speed limit,to achieve the effect of traffic flow optimization.
基金supported in part by the National Natural Science Foundation of China under Grant No.52175490.
文摘The shop scheduling problem with limited buffers has broad applications in real-world production scenarios,so this research direction is of great practical significance.However,there is currently little research on the hybrid flow shop scheduling problem with limited buffers(LBHFSP).This paper deeply investigates the LBHFSP to optimize the goal of the total completion time.To better solve the LBHFSP,a multi-level subpopulation-based particle swarm optimization algorithm(MLPSO)is proposed,which is founded on the attributes of the LBHFSP and the shortcomings of the basic PSO(particle swarm optimization)algorithm.In MLPSO,firstly,considering the impact of the limited buffers on the process of subsequent operations,a specific circular decoding strategy is developed to accommodate the characteristics of limited buffers.Secondly,an initialization strategy based on blocking time is designed to enhance the quality and diversity of the initial population.Afterward,a multi-level subpopulation collaborative search is developed to prevent being trapped in a local optimum and improve the global exploration capability.Additionally,a local search strategy based on the first blocked job is designed to enhance the MLPSO algorithm’s exploitation capability.Lastly,numerous experiments are carried out to test the performance of the proposed MLPSO by comparing it with classical intelligent optimization and popular algorithms in recent years.The results confirm that the proposed MLPSO has an outstanding performance when compared to other algorithms when solving LBHFSP.
基金supported by the National Natural Science Foundation of China(Grant Nos.52174036,52234003)the Sichuan Province Science and Technology Program(Grant No.2024NSFSC0199)the Joint Fund for Innovation and Development of Chongqing Natural Science Foundation(Grant No.2023NSCQ-LZX0184).
文摘Hydraulic fracturing and commingle production of multiple layers are extensively adopted in unconventional tight gas reservoirs.Accurate determination of parameters of individual layers in multilayered tight gas reservoirs is essential for well performance evaluation and development strategy optimization.However,most analytical models for fractured vertical wells in stratified gas reservoirs focus on fully penetrated hydraulic fractures,neglecting the influence of partial penetration of hydraulic fractures.This paper presents a semi-analytical model to investigate the transient pressure behavior of vertically fractured wells in dual porosity multi-layered tight gas reservoirs.The partial penetration of hydraulic fracture,the vertical heterogeneities of layer properties,the differences between hydraulic fracture lengths in each layer and the stress sensitivity are all incorporated in the proposed model.The point-source solution,Laplace transformation,Fourier transformation,Pedrosa's transformation,perturbation technique,and the superposition principle are applied to obtain the analytical solution of transient pressure responses.The proposed model is validated against a commercial software,and the transient pressure behavior of vertically fractured wells in multi-layered tight gas reservoirs are analyzed.Based on the characteristics of the type curves,seven flow regimes can be identified,including wellbore storage,transitional flow period,reservoir linear flow period,vertical pseudo-radial flow in fracture system,inter-porosity flow period,late-time pseudo-radial flow period,and the boundary-dominated flow period.Sensitivity analyses reveal that the penetration ratio of hydraulic fracture has primary influence on early-time transient pressure behavior and production contribution,while the stress sensitivity mainly affects the late-time transient pressure behavior.Gas production at the initial stage is mainly contributed by the high-pressure/high-permeability layer,and gas backflow will occur during initial production stage for obviously unequal initial formation pressures.Finally,two field cases are conducted to illustrate the applicability of the proposed model.The model and corresponding conclusions can provide technical support for performance analysis of tight gas reservoirs.
文摘AIM:To find the effective contrast enhancement method on retinal images for effective segmentation of retinal features.METHODS:A novel image preprocessing method that used neighbourhood-based improved contrast limited adaptive histogram equalization(NICLAHE)to improve retinal image contrast was suggested to aid in the accurate identification of retinal disorders and improve the visibility of fine retinal structures.Additionally,a minimal-order filter was applied to effectively denoise the images without compromising important retinal structures.The novel NICLAHE algorithm was inspired by the classical CLAHE algorithm,but enhanced it by selecting the clip limits and tile sized in a dynamical manner relative to the pixel values in an image as opposed to using fixed values.It was evaluated on the Drive and high-resolution fundus(HRF)datasets on conventional quality measures.RESULTS:The new proposed preprocessing technique was applied to two retinal image databases,Drive and HRF,with four quality metrics being,root mean square error(RMSE),peak signal to noise ratio(PSNR),root mean square contrast(RMSC),and overall contrast.The technique performed superiorly on both the data sets as compared to the traditional enhancement methods.In order to assess the compatibility of the method with automated diagnosis,a deep learning framework named ResNet was applied in the segmentation of retinal blood vessels.Sensitivity,specificity,precision and accuracy were used to analyse the performance.NICLAHE–enhanced images outperformed the traditional techniques on both the datasets with improved accuracy.CONCLUSION:NICLAHE provides better results than traditional methods with less error and improved contrastrelated values.These enhanced images are subsequently measured by sensitivity,specificity,precision,and accuracy,which yield a better result in both datasets.
