Hydrocyclones are mechanical devices used in classifying and separating many different types of materials.A classification function of the hydrocyclone has been continually developed for solid–liquid separation.In th...Hydrocyclones are mechanical devices used in classifying and separating many different types of materials.A classification function of the hydrocyclone has been continually developed for solid–liquid separation.In the classification process of solids from liquids,it is desirable to reduce the amount of misplaced material;therefore,the separation sharpness,α(alpha),is a parameter that helps in evaluating misplaced material and has been developed as a model to help the designer predict the performance of the classification.However,the problem with the separation sharpness model is that it cannot be used outside the range of conditions under which it was developed.Therefore,this research aimed to develop the separation sharpness model to predict more accurately and cover a wide range of conditions using the multiple linear regression method.The new regression model of separation sharpness was based on a wide range of both experimental and industrial data-sets of 431 tests collaborating with the additional experiments of 117 tests that were obtained from a total of 548 tests.The new model of separation sharpness can be used in the range of 30–762 mm hydrocyclone body diameters and feed solid concentrations in the range of 0.5 wt%–80 wt%.When compared with the experimental separation sharpness,the accuracy of the separation sharpness model prediction has an error of 4.53%and^of 0.973.展开更多
The 660-km discontinuity that separates the Earth's upper and lower mantle has primarily been attributed to phase changes in olivine and other minerals.Resolving the sharpness is essential for predicting the compo...The 660-km discontinuity that separates the Earth's upper and lower mantle has primarily been attributed to phase changes in olivine and other minerals.Resolving the sharpness is essential for predicting the composition of the mantle and for understanding its dynamic effects.In this study,we used S-to-P conversions from the 660-km interface,termed S660P,arriving in the P-wave coda from one earthquake in the Izu–Bonin subduction zone recorded by stations in Alaska.The S660P signals were of high quality,providing us an unprecedented opportunity to resolve the sharpness of the discontinuity.Our study demonstrated,based on the impedance contrast given by the IASP91 model,that the discontinuity has a transitional thickness of^5 km.In addition,we observed a prominent arrival right after the S660P,which was best explained by S-to-P conversions from a deeper discontinuity at a depth of^720 km with a transitional thickness of^20 km,termed S720P.The 720-km discontinuity is most likely the result of a phase transition from majoritic garnet to perovskite in the segregated oceanic crust(mainly the mid-oceanic ridge basalt composition)at the uppermost lower mantle beneath this area.The inferred phase changes are also consistent with predictions from mineral physics experiments.展开更多
It is commonly known that riblets with sharper tip generally have better turbulent drag reduction capacity,which,however,poses great challenges for manufacturing and makes the riblets vulnerable to tip erosion.In this...It is commonly known that riblets with sharper tip generally have better turbulent drag reduction capacity,which,however,poses great challenges for manufacturing and makes the riblets vulnerable to tip erosion.In this study,we show that a scalloped riblet which is not as sharp in the tip as corresponding triangular riblet with same height-width ratio,nevertheless has a larger protrusion height,a quantity solely depending on the riblet shape and calculated through a boundary element algorithm in this study,and thus a higher projected drag reduction rate.In addition,it is found that,when subjected to tip rounding,this scalloped riblet performs better in terms of protrusion height than corresponding parabolic riblet,which indicates stronger resilience to riblet tip erosion.With the class of scalloped riblets,designed by smoothly connecting two third-order polynomials and thus the tip sharpness and valley curvature can be well defined,it is revealed that two mechanisms,one for the valley curvature at the viscous limit and one for the tip sharpness at infinite deep limit,determine the protrusion height,and thus the projected drag reduction capacity.Direct numerical simulations are then carried out to investigate controlled boundary layer transition with the scalloped riblet of width s+=20 and 5+=60.A 7.8%drag reduction in the turbulent region is found for the smaller riblet with a preferable transition delay,while for the larger riblet transition is promoted and drag is increased in the turbulent region.It is also found that the area fraction of high drag region around the riblet tips is basically the same for the two cases.Surprisingly,even higher drag is found around the tip region for the smaller drag-reducing riblets.On the other hand,a much smaller drag coefficient is found in the valley of the smaller riblet,which results in the reduction of turbulent drag.It is thus inferred that the issue of sharp riblet tip,that hard to manufacture and deteriorate substantially when subjected to tip erosion,could be mitigated by optimization of the riblet geometry.展开更多
Quantitative measurement of the cutter blade sharpness is yet a difficult problem, since so far there has been no appropriate testing method. In this paper, a technique is introduced for measuring the cutter blade sha...Quantitative measurement of the cutter blade sharpness is yet a difficult problem, since so far there has been no appropriate testing method. In this paper, a technique is introduced for measuring the cutter blade sharpness at different testing conditions. The sharpness of cutter blades are measured by detecting the force to cut off the fiber with a material strength testing machine, and the results indicated that the technique could be used to measure the cutter blade sharpness satisfactorily. The fiber tension and downward speed of cutter blades are recommended to be 4.9 cN and 50 mm/min respectively for cutting 0.22 mm PET fiber.展开更多
As to probe the factors affecting the roughness and surface properties of work piece in mirco-cutting machining process, according to the principle of energy balance, using the method of experiments combining with the...As to probe the factors affecting the roughness and surface properties of work piece in mirco-cutting machining process, according to the principle of energy balance, using the method of experiments combining with theoretical analysis, this paper investigates the effect of cutting edge radius on the unit cutting force, the cutting component forces ratio Fy/Fz, as well as the roughness and surface properties of the work-piece. Experimental results show that the value of tool cutting edge arc ρ has a significant impact on elastic-plastic deformation of the cutting area, and its influence on the surface quality of processing and precision is greater than common cutting. The method of calculating the theoretical limits of the diamond tool cutting edge radius is feasible. The value of 0.0001 μm has some guiding significance for the developement of suitable cutting thickness to ensure the normal cutting.展开更多
We obtain some optimal properties on weighted modulation spaces. We find the necessary and sufficient conditions for product inequalities, convolution inequalities and embedding on weighted modulation spaces. Especial...We obtain some optimal properties on weighted modulation spaces. We find the necessary and sufficient conditions for product inequalities, convolution inequalities and embedding on weighted modulation spaces. Especially, we establish the analogue of the sharp Sobolev embedding theorem on weighted modulation spaces.展开更多
We present a variational method for subdivision surface reconstruction from a noisy dense mesh. A new set of subdivision rules with continuous sharpness control is introduced into Loop subdivision for better modeling ...We present a variational method for subdivision surface reconstruction from a noisy dense mesh. A new set of subdivision rules with continuous sharpness control is introduced into Loop subdivision for better modeling subdivision surface features such as semi-sharp creases, creases, and corners. The key idea is to assign a sharpness value to each edge of the control mesh to continuously control the surface features.Based on the new subdivision rules, a variational model with L_1 norm is formulated to find the control mesh and the corresponding sharpness values of the subdivision surface that best fits the input mesh. An iterative solver based on the augmented Lagrangian method and particle swarm optimization is used to solve the resulting non-linear, non-differentiable optimization problem. Our experimental results show that our method can handle meshes well with sharp/semi-sharp features and noise.展开更多
The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of ...The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of Navier slip conditions on exchange flows within a long channel connecting two large reservoirs of differing salinity.These horizontal density gradients drive the flow.We modify the recent one-dimensional theory,developed to avoid runaway stratification,to account for the presence of uniform slip walls.By adjusting the parameters of the horizontal density gradient based on the slip factor,we resolve analytically various flow regimes ranging from high diffusion to transitional high advection.These regimes are governed by physical parameters like channel aspect ratio,slip factor,Schmidt number,and gravitational Reynolds number.Our solutions align perfectly with ones in the no-slip limit.More importantly,under the conditions of no net flow across the channel and high Schmidt number(where stratification is concentrated near the channel’s mid-layer),we derive a closed-form solution for the slip parameter,aspect ratio,and gravitational Reynolds number that describes the interface’s behavior as a sharp interface separating two distinct zones.This interface,arising from hydrostatic wall gradients,ultimately detaches the low-and high-density regimes throughout the channel when the gravitational Reynolds number is inversely proportional to the aspect ratio for a fixed slip parameter.This phenomenon,observed previously in 2D numerical simulations with no-slip walls in the literature,is thus confirmed by our theoretical results.Our findings further demonstrate that wall slip leads to distinct and diverse flow regimes.展开更多
Sharp eyespot(Rhizoctonia cerealis)is a widespread soil-borne fungal disease that poses a severe threat to wheat health,and it is one of the main obstacles to achieving stable and high-quality wheat yields in China.Ou...Sharp eyespot(Rhizoctonia cerealis)is a widespread soil-borne fungal disease that poses a severe threat to wheat health,and it is one of the main obstacles to achieving stable and high-quality wheat yields in China.Our collaborative team has developed a novel,efficient,and low-toxicity fungicide named Y17991(N-(2-(2,4-bis-(trifluoromethyl)phenoxy)phenyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide).Preliminary laboratory tests confirmed the significant inhibitory effect of this agent on R.cerealis.Large-area field trials also demonstrated its efficacy,with a disease prevention index of 83.52%,which is 1.97%greater than that of the widely used thifluzamide,and it significantly increased the wheat yield.Moreover,this study explored the impacts of Y17991 on the structure and function of the microbial community in wheat rhizosphere soil.Bacterial communities were more strongly affected than fungal communities.Y17991 significantly modulated key amino acid metabolic pathways and certain biosynthetic processes in diseased wheat rhizospheres,and it also enhanced certain biosynthetic pathways and metabolic activities in healthy wheat rhizospheres.Additionally,the application of Y17991 regulated rhizosphere metabolites,thus exerting significant control over the microbial community.We identified 15 microbial strains potentially involved in the prevention and treatment of R.cerealis,and Y17991 treatment promoted the growth of Pedobacter and Bacillus strains.These strains not only aid in plant growth but they also have the potential for disease prevention.In summary,Y17991 application at a reasonable dose does not cause significant disruption to nontarget rhizosphere microbial communities.In future studies,we will continue to investigate the impacts of Y17991 on nonmicrobial components in soil ecosystems,such as protozoa and nematodes.Our research provides a theoretical basis for the scientific application and promotion of new fungicides and offers a significant reference for establishing a comprehensive system for assessing the ecological impact of pesticides on the environment.展开更多
BACKGROUND Sharp foreign body ingestion can cause gastrointestinal tract mucosa injury and requires proper endoscopic removal.Typically,protective devices are used to reduce mucosal damage.This case presents an altern...BACKGROUND Sharp foreign body ingestion can cause gastrointestinal tract mucosa injury and requires proper endoscopic removal.Typically,protective devices are used to reduce mucosal damage.This case presents an alternative approach for the endoscopic removal of a large,irregular,and sharp foreign body(chicken bone)when traditional protective devices are inadequate,thus contributing to the management of such ingestions.CASE SUMMARY A 57-year-old male presented with a history of swallowing an irregular and sharp-pointed chicken bone.Emergent endoscopy showed it was tightly embedded in the esophageal wall,with minor bleeding.The chicken bone was grasped and moved cautiously using a foreign forceps.It was loosened after repeated attempts but could not pass through the pharynx.Considering possible mucosal damage,it was carefully pushed into the stomach cavity and then wrapped in a condom.The chicken bone was retrieved uneventfully by grasping the open edge of the condom with foreign forceps.No additional damage was found,except for primary esophageal injuries caused by the embedded chicken bone.The patient was discharged on the following day.Our experience demonstrated that condoms can be an alternative as a protective device under such conditions.CONCLUSION Condoms can serve as an alternative when traditional protective devices are unsuitable.Because of its smooth and oily nature,it can provide mucosal protection and lubrication during endoscopic removal.展开更多
This study investigates the bifurcation dynamics underlying rhythmic transitions in a biophysical hippocampal–cortical neural network model.We specifically focus on the membrane potential dynamics of excitatory neuro...This study investigates the bifurcation dynamics underlying rhythmic transitions in a biophysical hippocampal–cortical neural network model.We specifically focus on the membrane potential dynamics of excitatory neurons in the hippocampal CA3 region and examine how strong coupling parameters modulate memory consolidation processes.Employing bifurcation analysis,we systematically characterize the model's complex dynamical behaviors.Subsequently,a characteristic waveform recognition algorithm enables precise feature extraction and automated detection of hippocampal sharp-wave ripples(SWRs).Our results demonstrate that neuronal rhythms exhibit a propensity for abrupt transitions near bifurcation points,facilitating the emergence of SWRs.Critically,temporal rhythmic analysis reveals that the occurrence of a bifurcation is not always sufficient for SWR formation.By integrating one-parameter bifurcation analysis with extremum analysis,we demonstrate that large-amplitude membrane potential oscillations near bifurcation points are highly conducive to SWR generation.This research elucidates the mechanistic link between changes in neuronal self-connection parameters and the evolution of rhythmic characteristics,providing deeper insights into the role of dynamical behavior in memory consolidation.展开更多
One of the most notable developments in the asset management industry in recent decades has been the growth of algorithmic trading.At the same time,significant structural changes in the industry have occurred,with pas...One of the most notable developments in the asset management industry in recent decades has been the growth of algorithmic trading.At the same time,significant structural changes in the industry have occurred,with passive investing gaining momentum.The intersection of these two major trends poses special challenges during market downturns,magnifying portfolio losses and leading to significant outflows.Emerging market(EM)investors have seen two major downturn events in the 2020s,namely the COVID-19 pandemic and the Russia-Ukraine conflict,both of which have strongly affected EM portfolios’risk-return profiles and increased their correlations with their developed market counterparts,eliminating much or all of EMs’diversification benefits.This has led to major capital outflows from EM countries,further destabilizing these fragile economies.Against this backdrop,we argue that capital need not exit these riskier markets during periods of turmoil and support this by developing a second-generation Automated Adaptive Trading System(AATS)back-tested on a relevant,diversified EM portfolio that tracks the Morgan Stanley Capital International(MSCI)Emerging Markets Index during a volatile period characterized by negative returns,high risk,and a high correlation with global markets for the buy-and-hold EM portfolio.The system incorporates an Autoregressive Moving Average-Generalized AutoRegressive Conditional Heteroskedasticity model that offers an interpretability advantage over machine-learning methods.The main strength of the AATS is its ability to allow the embedded hybrid forecasting model to adapt to the changing environments that characterize EMs.This is done by implementing a recursive window technique and running a user-specified fitness function to dynamically optimize the mean equation parameters throughout the lead time.Back-testing several configurations of the flexible AATS consistently reveals its superiority while assuring the robustness of the results.We conclude that with the right investment tools,EMs continue to offer compelling opportunities that should not be overlooked.The novel AATS proposed in this study is such a tool,providing active EM investors with substantial value-added through its ability to generate abnormal returns,and can help to enhance the resilience of EMs by mitigating the cost of crises for those countries.展开更多
In this paper,the authors study the multilinear commutators generated by a class of multilinear singular integral operators with generalized kernels and Lipschitz functions.By establishing the sharp maximal estimates,...In this paper,the authors study the multilinear commutators generated by a class of multilinear singular integral operators with generalized kernels and Lipschitz functions.By establishing the sharp maximal estimates,the boundedness of this kind of multilinear commutators on product of weighted Lebesgue spaces can be obtained.展开更多
Heterointerfaces have been pivotal in unveiling extraordinary interfacial properties and enabling multifunctional material platforms.Despite extensive research on all-oxide interfaces,heterointerfaces between differen...Heterointerfaces have been pivotal in unveiling extraordinary interfacial properties and enabling multifunctional material platforms.Despite extensive research on all-oxide interfaces,heterointerfaces between different material classes,such as oxides and nitrides,remain underexplored.Here we present the fabrication of atomically sharp heterointerfaces between antiperovskite Ni_(3)InN and perovskite SrVO_(3).Leveraging layer-resolved scanning transmission electron microscopy and electron energy loss spectroscopy,we identified pronounced charge transfer across the well-ordered interface.First-principles calculations confirmed our experimental observations and further predicted an emergent magnetic moment within the Ni_(3)InN layer due to the charge transfer.These findings pave the way for novel electronic and spintronic applications by enabling tunable interfacial properties in nitride/oxide systems.展开更多
In sharp contrast to Western urbanization models, the distinctive feature of China's rapid urbanization lies in the production of space. This is not only a crucial entry point for comprehending China's urbaniz...In sharp contrast to Western urbanization models, the distinctive feature of China's rapid urbanization lies in the production of space. This is not only a crucial entry point for comprehending China's urbanization path but also provides a new orientation for global urban studies.展开更多
Physics-informed neural networks(PINNs)have prevailed as differentiable simulators to investigate flow in porous media.Despite recent progress PINNs have achieved,practical geotechnical scenarios cannot be readily sim...Physics-informed neural networks(PINNs)have prevailed as differentiable simulators to investigate flow in porous media.Despite recent progress PINNs have achieved,practical geotechnical scenarios cannot be readily simulated because conventional PINNs fail in discontinuous heterogeneous porous media or multi-layer strata when labeled data are missing.This work aims to develop a universal network structure to encode the mass continuity equation and Darcy’s law without labeled data.The finite element approximation,which can decompose a complex heterogeneous domain into simpler ones,is adopted to build the differentiable network.Without conventional DNNs,physics-encoded finite element network(PEFEN)can avoid spectral bias and learn high-frequency functions with sharp/steep gradients.PEFEN rigorously encodes Dirichlet and Neumann boundary conditions without training.Benefiting from its discretized formulation,the discontinuous heterogeneous hydraulic conductivity is readily embedded into the network.Three typical cases are reproduced to corroborate PEFEN’s superior performance over conventional PINNs and the PINN with mixed formulation.PEFEN is sparse and demonstrated to be capable of dealing with heterogeneity with much fewer training iterations(less than 1/30)than the improved PINN with mixed formulation.Thus,PEFEN saves energy and contributes to low-carbon AI for science.The last two cases focus on common geotechnical settings of impermeable sheet pile in singlelayer and multi-layer strata.PEFEN solves these cases with high accuracy,circumventing costly labeled data,extra computational burden,and additional treatment.Thus,this study warrants the further development and application of PEFEN as a novel differentiable network in porous flow of practical geotechnical engineering.展开更多
基金the NSTDA University Industry Research Collaboration(NUI-RC)Thailand for supporting the funding in the research。
文摘Hydrocyclones are mechanical devices used in classifying and separating many different types of materials.A classification function of the hydrocyclone has been continually developed for solid–liquid separation.In the classification process of solids from liquids,it is desirable to reduce the amount of misplaced material;therefore,the separation sharpness,α(alpha),is a parameter that helps in evaluating misplaced material and has been developed as a model to help the designer predict the performance of the classification.However,the problem with the separation sharpness model is that it cannot be used outside the range of conditions under which it was developed.Therefore,this research aimed to develop the separation sharpness model to predict more accurately and cover a wide range of conditions using the multiple linear regression method.The new regression model of separation sharpness was based on a wide range of both experimental and industrial data-sets of 431 tests collaborating with the additional experiments of 117 tests that were obtained from a total of 548 tests.The new model of separation sharpness can be used in the range of 30–762 mm hydrocyclone body diameters and feed solid concentrations in the range of 0.5 wt%–80 wt%.When compared with the experimental separation sharpness,the accuracy of the separation sharpness model prediction has an error of 4.53%and^of 0.973.
基金We are grateful for the thoughtful and constructive comments provided by two anonymous reviewers and the editor(Dr.Wei Leng).We also thank Jinfeng Hu for his contributions to this work at an early stage.Seismic data from the USArray network were accessed via the Data Management Center(DMC)of the Incorporated Research Institutions for Seismology(IRIS).Some figures were prepared using Generic Mapping Tools(GMT,Wessel and Smith,1999)GNUPLOT.This work was funded by the National Natural Science Foundation of China(grant no.91858205).
文摘The 660-km discontinuity that separates the Earth's upper and lower mantle has primarily been attributed to phase changes in olivine and other minerals.Resolving the sharpness is essential for predicting the composition of the mantle and for understanding its dynamic effects.In this study,we used S-to-P conversions from the 660-km interface,termed S660P,arriving in the P-wave coda from one earthquake in the Izu–Bonin subduction zone recorded by stations in Alaska.The S660P signals were of high quality,providing us an unprecedented opportunity to resolve the sharpness of the discontinuity.Our study demonstrated,based on the impedance contrast given by the IASP91 model,that the discontinuity has a transitional thickness of^5 km.In addition,we observed a prominent arrival right after the S660P,which was best explained by S-to-P conversions from a deeper discontinuity at a depth of^720 km with a transitional thickness of^20 km,termed S720P.The 720-km discontinuity is most likely the result of a phase transition from majoritic garnet to perovskite in the segregated oceanic crust(mainly the mid-oceanic ridge basalt composition)at the uppermost lower mantle beneath this area.The inferred phase changes are also consistent with predictions from mineral physics experiments.
基金the National Natural Science Foundation of China(Grant No.11702159)the EU-China Joint Project Drag Reduction via Turbulent Boundary Layer Flow Control(Grant No.690623).
文摘It is commonly known that riblets with sharper tip generally have better turbulent drag reduction capacity,which,however,poses great challenges for manufacturing and makes the riblets vulnerable to tip erosion.In this study,we show that a scalloped riblet which is not as sharp in the tip as corresponding triangular riblet with same height-width ratio,nevertheless has a larger protrusion height,a quantity solely depending on the riblet shape and calculated through a boundary element algorithm in this study,and thus a higher projected drag reduction rate.In addition,it is found that,when subjected to tip rounding,this scalloped riblet performs better in terms of protrusion height than corresponding parabolic riblet,which indicates stronger resilience to riblet tip erosion.With the class of scalloped riblets,designed by smoothly connecting two third-order polynomials and thus the tip sharpness and valley curvature can be well defined,it is revealed that two mechanisms,one for the valley curvature at the viscous limit and one for the tip sharpness at infinite deep limit,determine the protrusion height,and thus the projected drag reduction capacity.Direct numerical simulations are then carried out to investigate controlled boundary layer transition with the scalloped riblet of width s+=20 and 5+=60.A 7.8%drag reduction in the turbulent region is found for the smaller riblet with a preferable transition delay,while for the larger riblet transition is promoted and drag is increased in the turbulent region.It is also found that the area fraction of high drag region around the riblet tips is basically the same for the two cases.Surprisingly,even higher drag is found around the tip region for the smaller drag-reducing riblets.On the other hand,a much smaller drag coefficient is found in the valley of the smaller riblet,which results in the reduction of turbulent drag.It is thus inferred that the issue of sharp riblet tip,that hard to manufacture and deteriorate substantially when subjected to tip erosion,could be mitigated by optimization of the riblet geometry.
文摘Quantitative measurement of the cutter blade sharpness is yet a difficult problem, since so far there has been no appropriate testing method. In this paper, a technique is introduced for measuring the cutter blade sharpness at different testing conditions. The sharpness of cutter blades are measured by detecting the force to cut off the fiber with a material strength testing machine, and the results indicated that the technique could be used to measure the cutter blade sharpness satisfactorily. The fiber tension and downward speed of cutter blades are recommended to be 4.9 cN and 50 mm/min respectively for cutting 0.22 mm PET fiber.
文摘As to probe the factors affecting the roughness and surface properties of work piece in mirco-cutting machining process, according to the principle of energy balance, using the method of experiments combining with theoretical analysis, this paper investigates the effect of cutting edge radius on the unit cutting force, the cutting component forces ratio Fy/Fz, as well as the roughness and surface properties of the work-piece. Experimental results show that the value of tool cutting edge arc ρ has a significant impact on elastic-plastic deformation of the cutting area, and its influence on the surface quality of processing and precision is greater than common cutting. The method of calculating the theoretical limits of the diamond tool cutting edge radius is feasible. The value of 0.0001 μm has some guiding significance for the developement of suitable cutting thickness to ensure the normal cutting.
基金supported by National Natural Science Foundation of China(Grant Nos.113712951102610411471041 and 11471288)
文摘We obtain some optimal properties on weighted modulation spaces. We find the necessary and sufficient conditions for product inequalities, convolution inequalities and embedding on weighted modulation spaces. Especially, we establish the analogue of the sharp Sobolev embedding theorem on weighted modulation spaces.
基金supported by the National Natural Science Foundation of China (No. 61602015)an MOE AcRF Tier 1 Grant of Singapore (RG26/15)+2 种基金Beijing Natural Science Foundation (No. 4162019)open funding project of State Key Lab of Virtual Reality Technology and Systems at Beihang University (No. BUAAVR-16KF-06)the Research Foundation for Young Scholars of Beijing Technology and Business University
文摘We present a variational method for subdivision surface reconstruction from a noisy dense mesh. A new set of subdivision rules with continuous sharpness control is introduced into Loop subdivision for better modeling subdivision surface features such as semi-sharp creases, creases, and corners. The key idea is to assign a sharpness value to each edge of the control mesh to continuously control the surface features.Based on the new subdivision rules, a variational model with L_1 norm is formulated to find the control mesh and the corresponding sharpness values of the subdivision surface that best fits the input mesh. An iterative solver based on the augmented Lagrangian method and particle swarm optimization is used to solve the resulting non-linear, non-differentiable optimization problem. Our experimental results show that our method can handle meshes well with sharp/semi-sharp features and noise.
文摘The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of Navier slip conditions on exchange flows within a long channel connecting two large reservoirs of differing salinity.These horizontal density gradients drive the flow.We modify the recent one-dimensional theory,developed to avoid runaway stratification,to account for the presence of uniform slip walls.By adjusting the parameters of the horizontal density gradient based on the slip factor,we resolve analytically various flow regimes ranging from high diffusion to transitional high advection.These regimes are governed by physical parameters like channel aspect ratio,slip factor,Schmidt number,and gravitational Reynolds number.Our solutions align perfectly with ones in the no-slip limit.More importantly,under the conditions of no net flow across the channel and high Schmidt number(where stratification is concentrated near the channel’s mid-layer),we derive a closed-form solution for the slip parameter,aspect ratio,and gravitational Reynolds number that describes the interface’s behavior as a sharp interface separating two distinct zones.This interface,arising from hydrostatic wall gradients,ultimately detaches the low-and high-density regimes throughout the channel when the gravitational Reynolds number is inversely proportional to the aspect ratio for a fixed slip parameter.This phenomenon,observed previously in 2D numerical simulations with no-slip walls in the literature,is thus confirmed by our theoretical results.Our findings further demonstrate that wall slip leads to distinct and diverse flow regimes.
基金supported by the National Natural Science Foundation of China(32270296)the Shenzhen Postdoctoral Scientific Research,China(77000-42100004)+1 种基金the Key Basic Research and Development Program of Hubei Province,China(2020BBA052)the Natural Science Foundation of Guangdong Province,China(2024A1515010498)and the Fundamental Research Funds for the Central Universities,Sun Yat-sen University,China.
文摘Sharp eyespot(Rhizoctonia cerealis)is a widespread soil-borne fungal disease that poses a severe threat to wheat health,and it is one of the main obstacles to achieving stable and high-quality wheat yields in China.Our collaborative team has developed a novel,efficient,and low-toxicity fungicide named Y17991(N-(2-(2,4-bis-(trifluoromethyl)phenoxy)phenyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide).Preliminary laboratory tests confirmed the significant inhibitory effect of this agent on R.cerealis.Large-area field trials also demonstrated its efficacy,with a disease prevention index of 83.52%,which is 1.97%greater than that of the widely used thifluzamide,and it significantly increased the wheat yield.Moreover,this study explored the impacts of Y17991 on the structure and function of the microbial community in wheat rhizosphere soil.Bacterial communities were more strongly affected than fungal communities.Y17991 significantly modulated key amino acid metabolic pathways and certain biosynthetic processes in diseased wheat rhizospheres,and it also enhanced certain biosynthetic pathways and metabolic activities in healthy wheat rhizospheres.Additionally,the application of Y17991 regulated rhizosphere metabolites,thus exerting significant control over the microbial community.We identified 15 microbial strains potentially involved in the prevention and treatment of R.cerealis,and Y17991 treatment promoted the growth of Pedobacter and Bacillus strains.These strains not only aid in plant growth but they also have the potential for disease prevention.In summary,Y17991 application at a reasonable dose does not cause significant disruption to nontarget rhizosphere microbial communities.In future studies,we will continue to investigate the impacts of Y17991 on nonmicrobial components in soil ecosystems,such as protozoa and nematodes.Our research provides a theoretical basis for the scientific application and promotion of new fungicides and offers a significant reference for establishing a comprehensive system for assessing the ecological impact of pesticides on the environment.
文摘BACKGROUND Sharp foreign body ingestion can cause gastrointestinal tract mucosa injury and requires proper endoscopic removal.Typically,protective devices are used to reduce mucosal damage.This case presents an alternative approach for the endoscopic removal of a large,irregular,and sharp foreign body(chicken bone)when traditional protective devices are inadequate,thus contributing to the management of such ingestions.CASE SUMMARY A 57-year-old male presented with a history of swallowing an irregular and sharp-pointed chicken bone.Emergent endoscopy showed it was tightly embedded in the esophageal wall,with minor bleeding.The chicken bone was grasped and moved cautiously using a foreign forceps.It was loosened after repeated attempts but could not pass through the pharynx.Considering possible mucosal damage,it was carefully pushed into the stomach cavity and then wrapped in a condom.The chicken bone was retrieved uneventfully by grasping the open edge of the condom with foreign forceps.No additional damage was found,except for primary esophageal injuries caused by the embedded chicken bone.The patient was discharged on the following day.Our experience demonstrated that condoms can be an alternative as a protective device under such conditions.CONCLUSION Condoms can serve as an alternative when traditional protective devices are unsuitable.Because of its smooth and oily nature,it can provide mucosal protection and lubrication during endoscopic removal.
基金supported by the National Natural Science Foundation of China(Grant Nos.12272002 and 12372061)the R&D Program of Beijing Municipal Education Commission(Grant No.KM202310009004)+1 种基金the North China University of Technology(Grant No.2023XN075-01)the Youth Research Special Project of the North China University of Technology(Grant No.2025NCUTYRSP051)。
文摘This study investigates the bifurcation dynamics underlying rhythmic transitions in a biophysical hippocampal–cortical neural network model.We specifically focus on the membrane potential dynamics of excitatory neurons in the hippocampal CA3 region and examine how strong coupling parameters modulate memory consolidation processes.Employing bifurcation analysis,we systematically characterize the model's complex dynamical behaviors.Subsequently,a characteristic waveform recognition algorithm enables precise feature extraction and automated detection of hippocampal sharp-wave ripples(SWRs).Our results demonstrate that neuronal rhythms exhibit a propensity for abrupt transitions near bifurcation points,facilitating the emergence of SWRs.Critically,temporal rhythmic analysis reveals that the occurrence of a bifurcation is not always sufficient for SWR formation.By integrating one-parameter bifurcation analysis with extremum analysis,we demonstrate that large-amplitude membrane potential oscillations near bifurcation points are highly conducive to SWR generation.This research elucidates the mechanistic link between changes in neuronal self-connection parameters and the evolution of rhythmic characteristics,providing deeper insights into the role of dynamical behavior in memory consolidation.
基金funded by the EU’s NextGenerationEU instrument through the National Recovery and Resilience Plan of Romania-Pillar Ⅲ-C9-I8,managed by the Ministry of Research,Innovation and Digitalization,within the project entitled,Non-Gaussian self-similar processes:Enhancing mathematical tools and financial models for capturing complex market dynamics”,contract no.760243/28.12.2023,code CF 194/31.07.2023’.
文摘One of the most notable developments in the asset management industry in recent decades has been the growth of algorithmic trading.At the same time,significant structural changes in the industry have occurred,with passive investing gaining momentum.The intersection of these two major trends poses special challenges during market downturns,magnifying portfolio losses and leading to significant outflows.Emerging market(EM)investors have seen two major downturn events in the 2020s,namely the COVID-19 pandemic and the Russia-Ukraine conflict,both of which have strongly affected EM portfolios’risk-return profiles and increased their correlations with their developed market counterparts,eliminating much or all of EMs’diversification benefits.This has led to major capital outflows from EM countries,further destabilizing these fragile economies.Against this backdrop,we argue that capital need not exit these riskier markets during periods of turmoil and support this by developing a second-generation Automated Adaptive Trading System(AATS)back-tested on a relevant,diversified EM portfolio that tracks the Morgan Stanley Capital International(MSCI)Emerging Markets Index during a volatile period characterized by negative returns,high risk,and a high correlation with global markets for the buy-and-hold EM portfolio.The system incorporates an Autoregressive Moving Average-Generalized AutoRegressive Conditional Heteroskedasticity model that offers an interpretability advantage over machine-learning methods.The main strength of the AATS is its ability to allow the embedded hybrid forecasting model to adapt to the changing environments that characterize EMs.This is done by implementing a recursive window technique and running a user-specified fitness function to dynamically optimize the mean equation parameters throughout the lead time.Back-testing several configurations of the flexible AATS consistently reveals its superiority while assuring the robustness of the results.We conclude that with the right investment tools,EMs continue to offer compelling opportunities that should not be overlooked.The novel AATS proposed in this study is such a tool,providing active EM investors with substantial value-added through its ability to generate abnormal returns,and can help to enhance the resilience of EMs by mitigating the cost of crises for those countries.
基金Supported by the National Natural Science Foundation of China(11671397,11571160,12071052)the Yue Qi Young Scholar of China University of Mining and Technology(Beijing)。
文摘In this paper,the authors study the multilinear commutators generated by a class of multilinear singular integral operators with generalized kernels and Lipschitz functions.By establishing the sharp maximal estimates,the boundedness of this kind of multilinear commutators on product of weighted Lebesgue spaces can be obtained.
基金supported by the Beijing Natural Science Foundation(Grant No.JQ24002)the National Key Basic Research Program of China(Grant No.2020YFA0309100)+3 种基金the National Natural Science Foundation of China(Grant Nos.U22A20263,52250308,12304158,12325401,12274069,12404102,and 12474096)the Chinese Academy of Sciences(CAS)Project for Young Scientists in Basic Research(Grant No.YSBR-084)the CAS Youth Interdisciplinary Team,the Guangdong Basic and Applied Basic Research Foundation(Grant No.2022B1515120014)the Guangdong-Hong Kong-Macao Joint Laboratory for Neutron Scattering Science and Technology,and the International Young Scientist Fellowship of Institute of Physics,CAS.
文摘Heterointerfaces have been pivotal in unveiling extraordinary interfacial properties and enabling multifunctional material platforms.Despite extensive research on all-oxide interfaces,heterointerfaces between different material classes,such as oxides and nitrides,remain underexplored.Here we present the fabrication of atomically sharp heterointerfaces between antiperovskite Ni_(3)InN and perovskite SrVO_(3).Leveraging layer-resolved scanning transmission electron microscopy and electron energy loss spectroscopy,we identified pronounced charge transfer across the well-ordered interface.First-principles calculations confirmed our experimental observations and further predicted an emergent magnetic moment within the Ni_(3)InN layer due to the charge transfer.These findings pave the way for novel electronic and spintronic applications by enabling tunable interfacial properties in nitride/oxide systems.
文摘In sharp contrast to Western urbanization models, the distinctive feature of China's rapid urbanization lies in the production of space. This is not only a crucial entry point for comprehending China's urbanization path but also provides a new orientation for global urban studies.
基金supported by the National Natural Science Foundation of China(Grant Nos.42272338 and 41827807)Department of Transportation of Zhejiang Province,China(Grant No.202213).
文摘Physics-informed neural networks(PINNs)have prevailed as differentiable simulators to investigate flow in porous media.Despite recent progress PINNs have achieved,practical geotechnical scenarios cannot be readily simulated because conventional PINNs fail in discontinuous heterogeneous porous media or multi-layer strata when labeled data are missing.This work aims to develop a universal network structure to encode the mass continuity equation and Darcy’s law without labeled data.The finite element approximation,which can decompose a complex heterogeneous domain into simpler ones,is adopted to build the differentiable network.Without conventional DNNs,physics-encoded finite element network(PEFEN)can avoid spectral bias and learn high-frequency functions with sharp/steep gradients.PEFEN rigorously encodes Dirichlet and Neumann boundary conditions without training.Benefiting from its discretized formulation,the discontinuous heterogeneous hydraulic conductivity is readily embedded into the network.Three typical cases are reproduced to corroborate PEFEN’s superior performance over conventional PINNs and the PINN with mixed formulation.PEFEN is sparse and demonstrated to be capable of dealing with heterogeneity with much fewer training iterations(less than 1/30)than the improved PINN with mixed formulation.Thus,PEFEN saves energy and contributes to low-carbon AI for science.The last two cases focus on common geotechnical settings of impermeable sheet pile in singlelayer and multi-layer strata.PEFEN solves these cases with high accuracy,circumventing costly labeled data,extra computational burden,and additional treatment.Thus,this study warrants the further development and application of PEFEN as a novel differentiable network in porous flow of practical geotechnical engineering.
