The well-known Yau＇s uniformization conjecture states that any complete noncompact Kahler manifold with positive bisectional curvature is bi-holomorphic to the Euclidean space. The conjecture for the case of maximal ...The well-known Yau＇s uniformization conjecture states that any complete noncompact Kahler manifold with positive bisectional curvature is bi-holomorphic to the Euclidean space. The conjecture for the case of maximal volume growth has been recently confirmed, by G. Liu in [23]. In the first part, we will give a survey on thc progress. In the second part, we will consider Yau＇s conjecture for manifolds with non-maximal volume growth. We will show that the finiteness of the first Chern number Cn1 is an essential condition to solve Yau＇s conjecture by using algebraic embedding method. Moreover, we prove that, under bounded curvature conditions, Cn1 is automatically finite provided that there exists a positive line bundle with finite Chern number. In particular, we obtain a partial answer to Yau＇s uniformization conjecture on Kahler manifolds with minimal volume growth.展开更多
In this article, we show that the universal covering of any complete normal Kähler space of constant holomorphic sectional curvature on the regular locus is exactly biholomorphic to one of the complex projective ...In this article, we show that the universal covering of any complete normal Kähler space of constant holomorphic sectional curvature on the regular locus is exactly biholomorphic to one of the complex projective space, the complex Euclidean space or the complex Euclidean ball. Moreover, we also prove that in a normal Stein space any bounded domain with complete Bergman metric of constant holomorphic sectional curvature on the regular locus is necessarily biholomorphic to the complex Euclidean ball, by which we generalize the classical Lu Qi-Keng uniformization theorem to the singular setting.展开更多
A simplified calculation of the specimen’s stress-strain curve is generally conducted using the two-wave method by the split Hopkinson pressure bar(SHPB),which aligns the onset of the transmitted and reflected waves....A simplified calculation of the specimen’s stress-strain curve is generally conducted using the two-wave method by the split Hopkinson pressure bar(SHPB),which aligns the onset of the transmitted and reflected waves.However,this approach neglects the travel time of elastic waves within the specimen.Considering the travel time of elastic waves,this study quantitatively investigates the error characteristics and patterns of stress,strain,and strain rate in the specimen under different conditions using the theoretical two-wave method,and compares the results with those obtained using the onset-aligned twowave method.The study reveals that the stress-time curves derived from the theoretical two-wave method are lower than the actual stress curves,whereas those obtained from the onset-aligned two-wave method are consistently higher than the actual stress curves,with the stress deviation approximating a constant value when the dimensionless time exceeds 2.0.The starting point of the stress-strain curves obtained by the theoretical two-wave method is not zero but a point on the strain axis,whereas the onset-aligned two-wave method always starts at zero.However,the slopes of the stress-strain curves obtained by both methods differ from the actual Young’s modulus of the material,and functional relationships between the slopes and the actual Young’s modulus are provided.This research offers theoretical guidance for the refined design of SHPB experiments and the accurate processing of data.展开更多
In this paper, the problem of cubature Kalman fusion filtering(CKFF) is addressed for multi-sensor systems under amplify-and-forward(AaF) relays. For the purpose of facilitating data transmission, AaF relays are utili...In this paper, the problem of cubature Kalman fusion filtering(CKFF) is addressed for multi-sensor systems under amplify-and-forward(AaF) relays. For the purpose of facilitating data transmission, AaF relays are utilized to regulate signal communication between sensors and filters. Here, the randomly varying channel parameters are represented by a set of stochastic variables whose occurring probabilities are permitted to exhibit bounded uncertainty. Employing the spherical-radial cubature principle, a local filter under AaF relays is initially constructed. This construction ensures and minimizes an upper bound of the filtering error covariance by designing an appropriate filter gain. Subsequently, the local filters are fused through the application of the covariance intersection fusion rule. Furthermore, the uniform boundedness of the filtering error covariance's upper bound is investigated through establishing certain sufficient conditions. The effectiveness of the proposed CKFF scheme is ultimately validated via a simulation experiment concentrating on a three-phase induction machine.展开更多
This paper studies the problem of the spectral radius of the uniform hypergraph determined by the signless Laplacian matrix.The upper bound of the spectral radius of a uniform hypergraph is obtained by using Rayleigh ...This paper studies the problem of the spectral radius of the uniform hypergraph determined by the signless Laplacian matrix.The upper bound of the spectral radius of a uniform hypergraph is obtained by using Rayleigh principle and the perturbation of the spectral radius under moving the edge operation,and the extremal hypergraphs are characterized for both supertree and unicyclic hypergraphs.The spectral radius of the graph is generalized.展开更多
The PICOSEC Micromegas(MM)is a precise timing gaseous detector based on a Cherenkov radiator coupled with a semi-transparent photocathode and an MM amplifying structure.It features a two-stage amplification process th...The PICOSEC Micromegas(MM)is a precise timing gaseous detector based on a Cherenkov radiator coupled with a semi-transparent photocathode and an MM amplifying structure.It features a two-stage amplification process that leads to a significant deterioration of non-uniformity when scaling up to larger areas.Since the performance of gaseous detectors is highly dependent on the choice of working gas,optimizing the gas mixture offers a promising solution to improve the uniformity performance.This paper addresses these challenges through a combined approach of simulation based on Garfield++and experimental studies.The simulation investigates the properties of different mixing fractions of gas mixtures and their impact on detector performance,including gain uniformity and time resolution.To verify the simulation results,experimental tests were conducted using a multi-channel PICOSEC MM prototype with different gas mixtures.The experimental results are consistent with the findings of the simulation,indicating that a higher concentration of neon significantly improves the detector’s gain uniformity.Furthermore,the influence of gas mixtures on time resolution was explored as a critical performance indicator.The study presented in this paper offers valuable insights for improving uniformity in large-area PICOSEC MM detectors and optimizing overall performance.展开更多
The excimer laser has important applications in many fields. Because of its non-uniform intensity distribution there are some limits in applications. This paper introduces rotational lens array to improve intensity di...The excimer laser has important applications in many fields. Because of its non-uniform intensity distribution there are some limits in applications. This paper introduces rotational lens array to improve intensity distributions. The intensity variation is reduced to 1 percent by computer simulation.展开更多
At our school,we have to wear uniforms every day.The problem is that all my classmates think the uniforms are ugly.We think young people should look smart,because①we would like to wear our own clothes.Our teachers th...At our school,we have to wear uniforms every day.The problem is that all my classmates think the uniforms are ugly.We think young people should look smart,because①we would like to wear our own clothes.Our teachers think that if we do that,we will concentrate much②on our clothes than our studies.We don't agree.展开更多
With the rapid advancement of 5G communication technology,increasingly stringent demands are placed on the performance and functionality of phase change switches.Given that RF and microwave signals exhibit characteris...With the rapid advancement of 5G communication technology,increasingly stringent demands are placed on the performance and functionality of phase change switches.Given that RF and microwave signals exhibit characteristics of high frequency,high speed,and high precision,it is imperative for phase change switches to possess fast,accurate,and reliable switching capabilities.Moreover,wafer-level compositional homogeneity and resistivity uniformity during semiconductor manufacturing are crucial for ensuring the yield and reliability of RF switches.By controlling magnetron sputter of GeTe through from four key parameters(pressure,power,Ar flow,and post-annealing)and incorporating elemental proportional compensation in the target,we achieved effective modulation over GeTe uniformity.Finally,we successfully demonstrated the process integration of GeTe phase-change RF switches on 6-inch scaled wafers.展开更多
The high temporal and spatial coherence of free electron lasers(FELs)reduces the uniformity of the illumination field,leading to scattering effects that blur the edges of patterns,resulting in diminished accuracy and ...The high temporal and spatial coherence of free electron lasers(FELs)reduces the uniformity of the illumination field,leading to scattering effects that blur the edges of patterns,resulting in diminished accuracy and clarity.Traditional imaging models regard the light source as fully incoherent,making it difficult to assess the impact of partially coherent light fields on imaging.If FELs are used in imaging systems,their coherence must be considered.To address this issue,this study explores the relationship between coherence,imaging quality and speckle contrast through a simulation method based on random phases.The method divides the light beam into temporal and spatial coherence cells,analyzes their interactions,and simulates imaging results under different coherence conditions.Additionally,speckle patterns for various illumination modes are calculated to evaluate their effects on speckle contrast and illumination uniformity.The results indicate that under different illumination modes,illumination uniformity decreases as coherence increases,while speckle contrast increases with higher coherence.In terms of imaging quality,higher coherence leads to an increase in both line edge roughness(LER)and line width roughness(LWR),thereby reducing the imaging quality.Additionally,the narrower the line width,the greater the impact of coherence on the imaging quality,resulting in poorer imaging performance.展开更多
Background This study investigated the effects of different non-starch polysaccharide(NSP)sources with NSP degrading enzymes(NSPases)and the influence on the mucosa-associated microbiota and intestinal immunity of nur...Background This study investigated the effects of different non-starch polysaccharide(NSP)sources with NSP degrading enzymes(NSPases)and the influence on the mucosa-associated microbiota and intestinal immunity of nursery pigs,on growth performance and carcass traits at market weight.Methods One hundred and sixty newly weaned pigs at 7.0±0.3 kg body weight(BW)were allotted in a 2×2 factorial with NSP sources and NSPases serving as factors.The 4 dietary treatments were:DDGS,corn distillers'dried grains with solubles as source of NSP;DDGS+NSPases(DDGS+),DDGS with xylanase at 0.01%,3,000 U/kg of feed andβ-mannanase at 0.05%,400 U/kg of feed;SHWB,soybean hulls and wheat bran replacing corn DDGS as the source of NSP;SHWB with NSPases(SHWB+),SHWB with xylanase at 0.01%,3,000 U/kg of feed andβ-mannanase at 0.05%,400 U/kg of feed.Pigs were fed for 37 d and housed in groups of 4 pigs per pen.At d 37,the median body weight pig in each pen was euthanized for sampling to analyze intestinal health parameters.Remaining pigs were fed a common diet for subsequent phases to evaluate the carryover effect on growth and carcass traits.Results The SHWB decreased(P<0.05)the relative abundance of Helicobacter,tended to increase(P=0.074)the relative abundance of Lactobacillus,increased(P<0.05)immunoglobulin G(IgG)in the jejunal mucosa,tended to increase(P=0.096)the villus height(VH)in the jejunum,and tended to improve ADG(P=0.099)and feed efficiency(P=0.068)during phase 1 compared to DDGS treatment.Supplementation of NSPases increased(P<0.05)Shannon index of diversity,increased the relative abundance of Streptococcus and Acinetobacter,and tended to increase(P=0.082)dry matter digestibility.The BW of pigs fed SHWB was more uniform(P<0.05)at the end of the 120 d study.Additionally,hot carcass weight of pigs fed SHWB tended to be more uniform(P=0.089)than DDGS treatment.Conclusion Soybean hulls and wheat bran replacing DDGS in nursery diets improved uniformity of pigs at market weight,which might be attributed to beneficial modulation of the mucosa-associated microbiota and enhanced intestinal morphology during the nursery phase.Supplementation of NSPases had beneficial effects on the intestinal mucosa-associated microbiota,digestibility,and intestinal immunity in SHWB treatment,whereas no carryover effects were overserved at market weight.展开更多
In this study,the pure erosion behaviour of pure iron and its erosion-corrosion behaviour under different anodic polarization currents were investigated in various cathodic reactions(oxygen reduction,hydrogen ion redu...In this study,the pure erosion behaviour of pure iron and its erosion-corrosion behaviour under different anodic polarization currents were investigated in various cathodic reactions(oxygen reduction,hydrogen ion reduction,and water reduction)using a cylindrical stirring system.The corrosion-enhanced erosion(C-E)rates were determined for each condition.The results revealed that pure iron displayed similar pure erosion behaviour across all three cathodic reactions.When the cathodic reactions involve hydrogen ion reduction or water reduction,the erosion-corrosion of pure iron manifested as uniform damage,with the reduction in hardness being the main cause of the C-E in this case.Conversely,in the case of oxy-gen reduction reaction as the cathodic reaction,the erosion-corrosion presented as pitting damage,with the reduction in hardness resulting from localized concentration of anodic current and the formation of easily worn protruding flaky iron structures at the edges of the pits as the main mechanism of the C-E.Moreover,linear and exponential relationships were found between the C-E rate and the anodic current density for uniform damage and pitting damage,respectively.Finally,the concept of surface equivalent hardness was proposed,along with the establishment of a mathematical model for surface equivalent hardness based on the relationships between the C-E rate and the anodic current density.Utilizing the surface equivalent hardness enables the evaluation of the erosion rate on material surfaces considering the coupled effect.展开更多
The double-sided lapping process is extensively employed in the manufacturing of wafers,optical windows,and seal rings due to its high efficiency and ability to achieve precise flatness.However,limited research has ex...The double-sided lapping process is extensively employed in the manufacturing of wafers,optical windows,and seal rings due to its high efficiency and ability to achieve precise flatness.However,limited research has explored the thickness uniformity among different workpieces after double-sided lapping,and the underlying mechanism remains unclear.To address the demand for higher precision,this paper first analyzed the relative kinematic model between the workpiece and the lapping plate to clarify the causes of thickness variations among workpieces after double-sided lapping.Subsequently,a finite element method(FEM)model was developed to account for the pressure distribution on the workpiece surfaces at the initial stage of the process.The results indicate that the number of workpieces influences the final thickness variation.Then,various sets of thin copper plates with different thicknesses were lapped,and the findings revealed that five copper plates processed simultaneously exhibited more uniform thickness compared to the three plates.The experimental results align well with the theoretical analysis.Ultimately,a thickness variation of less than 6μm was achieved on five copper plates measuringΦ100×2.9 mm.This study presents a comprehensive analysis of the mechanisms influencing thickness uniformity in the double-sided lapping process and provides practical guidelines for optimizing the process to achieve stringent precision standards in industrial applications.展开更多
Background Hatch weight(HW)affects broiler growth and low HW(LHW)often leads to suboptimal performance.Sodium butyrate(SB)has been shown to promote growth through enhanced intestinal health.This study investi-gated ho...Background Hatch weight(HW)affects broiler growth and low HW(LHW)often leads to suboptimal performance.Sodium butyrate(SB)has been shown to promote growth through enhanced intestinal health.This study investi-gated how broilers with different HW responded to in ovo SB injection and whether SB could enhance gut health and performance in LHW chicks.Ross 308 broiler eggs were injected on incubation d 12 with physiological saline(control)or SB at 0.1%(SB1),0.3%(SB3),or 0.5%(SB5).Post-hatch,male chicks from each treatment were categorized as high HW(HHW)or LHW and assigned to 8 groups in a 4×2 factorial design.Production parameters were recorded periodically.Intestinal weight,length,and gene expression related to gut barrier function and immune response were examined on d 14 and 42.Cecal microbiota dynamics and predicted functionality were analyzed using 16S rRNA gene sequencing.Results SB treatments did not affect hatchability.HHW-control group exhibited consistently better weight gain and FCR than LHW-control group.SB dose-dependently influenced performance and gut health in both HW catego-ries,with greater effects in LHW broilers at 0.3%.LHW-SB3 group attained highest body weight on d 42,exceeding controls but not significantly differing from HHW-SB3 group.LHW-SB3 group showed upregulation of gut-barrier genes CLDN1 in ileum,TJP1 in jejunum and anti-inflammatory cytokine IL-10 in both jejunum and ileum on d 14.Addi-tionally,LHW-SB3 group upregulated mucin-producing MUC6 gene in ileum,while HHW-SB5 group increased pro-inflammatory IL-12p40 cytokine in caecum on d 42.LHW-SB3 group demonstrated shorter relative intestinal lengths,while HHW-SB5 had longer lengths.HHW-control group had higher bacterial diversity and growth-promoting bacte-ria while LHW-control group harbored the potential pathogen Helicobacter.SB reshaped gut microbiota biodiversity,composition,and predicted metabolic pathways in both HW categories.The LHW-SB3 group exhibited highest alpha diversity on d 14 and most beneficial bacteria at all timepoints.HHW-SB5 group presented increased pathogenic Escherichia-Shigella and Campylobacter on d 42.Conclusions HW significantly affects subsequent performance and SB has differential effects based on HW.LHW chicks benefited more from 0.3%SB,showing improvements in growth,intestinal development,health,and gut microbiota characteristics.展开更多
In this study,we present a unified sparsity-driven framework that significantly enhances motion deblurring performance by integrating two key components:a custom-designed dataset and a low-rank module(LRM).This framew...In this study,we present a unified sparsity-driven framework that significantly enhances motion deblurring performance by integrating two key components:a custom-designed dataset and a low-rank module(LRM).This framework leverages the inherent sparsity of per-pixel blur kernels to bolster both deblurring accuracy and model interpretability.Firstly,we propose an adaptive-basis decomposition-based deblurring(ADD)approach,which constructs a tailored training dataset to enhance the generalization capacity of the deblurring network.The ADD framework adaptively decomposes motion blur into sparse basis elements,effectively addressing the intricacies associated with non-uniform blurs.Secondly,an LRM is proposed to improve the interpretability of deblurring models as a plug-and-play module,primarily designed to identify and harness the intrinsic sparse features in sharp images.A series of ablation studies have been conducted to substantiate the synergistic advantages of combining the proposed ADD with the LRM for overall improvement in deblurring efficacy.Subsequently,we empirically demonstrate through rigorous experimentation that incorporating the LRM into an existing Uformer network leads to substantial enhancement in reconstruction performance.This integration yields a sparsity-guided low-rank network(SGLRN).Operating under the overarching principle of sparsity,SGLRN consistently outperforms state-of-the-art methods across multiple standard deblurring benchmarks.Comprehensive experimental results,assessed through quantitative metrics and qualitative visual evaluations,provide compelling evidence of its effectiveness.The overall deblurring results are available at Google Drive.展开更多
The upper bound on the model error will be decreased when the mean square error and the maximum distance deviation are sufficiently small in the uniform designs for mixture experiments and the design is more robust fo...The upper bound on the model error will be decreased when the mean square error and the maximum distance deviation are sufficiently small in the uniform designs for mixture experiments and the design is more robust for the model.However,the analytical expressions of MSED and MD are currently only available in the hypercube,but both types of deviations in other studies are just approximations.Although it can obtain good approximations in the low-dimensional case,the calculation will be more complicated for an experiment with more variables.Therefore,in this paper,an algorithm based on lattice point partitioning design is proposed to obtain the analytical expression of the MSED and MD in the region covered by the lattice points.Furthermore,the design’s optimality is considered and illustrated by examples under the same uniformity.展开更多
In this paper,we introduce a new geometric constant R_(X)(κ)based on isosceles orthogonality.First,we explore some basic properties of this new constant and then provide several examples to estimate its exact values ...In this paper,we introduce a new geometric constant R_(X)(κ)based on isosceles orthogonality.First,we explore some basic properties of this new constant and then provide several examples to estimate its exact values in certain specific Banach spaces.Next,we investigate the relationships between this new constant and other classical constants.Specifically,we establish an inequality relationship between it and the J(X)constant,as well as an identity relationship between it and theρX(t)constant.Furthermore,we characterize some geometric properties of Banach spaces by means of this new constant.Finally,by restricting the above-mentioned constant to the unit sphere,we introduce another new constant,calculate its upper and lower bounds,and present a relevant example.展开更多
Scour around bridge pier foundations is a complex phenomenon that can threaten structural stability.Accurate prediction of scour depth around compound piers remains challenging for bridge engineers.This study investig...Scour around bridge pier foundations is a complex phenomenon that can threaten structural stability.Accurate prediction of scour depth around compound piers remains challenging for bridge engineers.This study investigated the effect of foundation elevation on scour around compound piers and developed reliable scour depth prediction models for economical foundation design.Experiments were conducted under clear-water conditions using two circular piers:(1)a uniform pier(with a diameter of D)and(2)a compound pier consisting of a uniform pier resting on a circular foundation(with a foundation diameter(D_(f))of 2D)positioned at various elevations(Z)relative to the channel bed.Results showed that foundation elevation significantly affected scour depth.Foundations at or below the bed(Z/D≥0)reduced scour,while those projecting into the flow field(Z/D<0)increased scour.The optimal foundation elevation was found to be 0.1D below the bed level,yielding a 57%reduction in scour depth compared to the uniform pier due to its shielding effect against downflow and horseshoe vortices.In addition,regression,artificial neural network(ANN),and M5 model tree models were developed using experimental data from this and previous studies.The M5 model outperformed the traditional HEC-18 equation,regression,and ANN models,with a coefficient of determination greater than 0.85.Sensitivity analysis indicated that flow depth,foundation elevation,and diameter significantly influenced scour depth prediction,whereas sediment size had a lesser impact.展开更多
Long-duration energy storage has become critical for renewable energy integration.While redox flow batteries,especially vanadium-based systems,are scaling up in capacity,their performance at the stack level remains in...Long-duration energy storage has become critical for renewable energy integration.While redox flow batteries,especially vanadium-based systems,are scaling up in capacity,their performance at the stack level remains insufficiently optimized,demanding more profound mechanistic studies and engineering refinements.To address the difficulties in resolving the flow inhomogeneity at the stack scale,this study establishes a multi-physics field coupling model and analyzes the pressure distributions,flow rate differences,active substance concentration,and electrochemical characteristics.The results show that the uneven cell pressure distribution is a key factor affecting the consistency of the system performance,and the increase in the flow rate improves the reactant homogeneity,with both the average concentration and the uniformity factor increasing with the flow rate.In contrast,high current densities lead to an increased imbalance between electrochemical depletion and reactant replenishment,resulting in a significant decrease in reactant concentration in the under-ribs region.In addition,a higher flow rate can expand the high-current-density region where the stack operates efficiently.This study provides a theoretical basis for optimizing the design of the stack components.展开更多
The mineralization process of microbial-induced calcium carbonate precipitation(MICP)is influenced by many factors,and the uniformity of the calcium carbonate precipitation has become the main focus and challenge for ...The mineralization process of microbial-induced calcium carbonate precipitation(MICP)is influenced by many factors,and the uniformity of the calcium carbonate precipitation has become the main focus and challenge for MICP technology.In this study,the uniformity of the saturated calcareous sand treated with MICP was in-vestigated through one-dimensional calcareous sand column tests and model tests.The coefficient of variation was employed in one-dimensional sand column tests to investigate the impact of injection rate,cementation solution concentration,and number of injection cycles on the uniformity of the MICP treatment.Additionally,model tests were conducted to investigate the impact of injection pressure and methods on the treatment range and uniformity under three-dimensional seepage conditions.Test results demonstrate that the reinforcement strength and uniformity are significantly influenced by the injection rate of the cementation solution,with a rate of 3 mL/min,yielding a favorable treatment effect.Excessive concentration of the cementation solution can lead to significant non-uniformity and a reduction in the compressive strength of MICP-treated samples.Conversely,excessively low concentrations may result in decreased bonding efficiency.Among the four considered con-centrations,0.5 mol/L and 1 mol/L exhibit superior reinforcing effects.The morphological development of calcareous sandy foundation reinforcement is associated with the spatial distribution pattern of the bacterial solution,exhibiting a relatively larger reinforcement area in proximity to the lower region of the model and a gradually decreasing range towards the upper part.Under three-dimensional seepage conditions,in addition to the non-uniform radial cementation along the injection pipe,there is also vertical heterogeneity of cementation along the length of the injection pipe due to gravitational effects,resulting in preferential deposition of calcium carbonate at the lower section,The application of injection pressure and a double-pipe circulation injection method can mitigate the accumulation of bacterial solution and cementation solution at the bottom,thereby improving the reinforcement range and uniformity.展开更多
文摘The well-known Yau＇s uniformization conjecture states that any complete noncompact Kahler manifold with positive bisectional curvature is bi-holomorphic to the Euclidean space. The conjecture for the case of maximal volume growth has been recently confirmed, by G. Liu in [23]. In the first part, we will give a survey on thc progress. In the second part, we will consider Yau＇s conjecture for manifolds with non-maximal volume growth. We will show that the finiteness of the first Chern number Cn1 is an essential condition to solve Yau＇s conjecture by using algebraic embedding method. Moreover, we prove that, under bounded curvature conditions, Cn1 is automatically finite provided that there exists a positive line bundle with finite Chern number. In particular, we obtain a partial answer to Yau＇s uniformization conjecture on Kahler manifolds with minimal volume growth.
基金supported by the National Key R&D Program of China(Grant No.2021YFA1002600)NSFC(Grant No.12201060)。
文摘In this article, we show that the universal covering of any complete normal Kähler space of constant holomorphic sectional curvature on the regular locus is exactly biholomorphic to one of the complex projective space, the complex Euclidean space or the complex Euclidean ball. Moreover, we also prove that in a normal Stein space any bounded domain with complete Bergman metric of constant holomorphic sectional curvature on the regular locus is necessarily biholomorphic to the complex Euclidean ball, by which we generalize the classical Lu Qi-Keng uniformization theorem to the singular setting.
基金supported by the National Natural Science Foundation of China (Grant Nos.U2341244,12172179,and 11772160)the Postgraduate Research&Practice Innovation Program of Jiangsu Province.
文摘A simplified calculation of the specimen’s stress-strain curve is generally conducted using the two-wave method by the split Hopkinson pressure bar(SHPB),which aligns the onset of the transmitted and reflected waves.However,this approach neglects the travel time of elastic waves within the specimen.Considering the travel time of elastic waves,this study quantitatively investigates the error characteristics and patterns of stress,strain,and strain rate in the specimen under different conditions using the theoretical two-wave method,and compares the results with those obtained using the onset-aligned twowave method.The study reveals that the stress-time curves derived from the theoretical two-wave method are lower than the actual stress curves,whereas those obtained from the onset-aligned two-wave method are consistently higher than the actual stress curves,with the stress deviation approximating a constant value when the dimensionless time exceeds 2.0.The starting point of the stress-strain curves obtained by the theoretical two-wave method is not zero but a point on the strain axis,whereas the onset-aligned two-wave method always starts at zero.However,the slopes of the stress-strain curves obtained by both methods differ from the actual Young’s modulus of the material,and functional relationships between the slopes and the actual Young’s modulus are provided.This research offers theoretical guidance for the refined design of SHPB experiments and the accurate processing of data.
基金supported in part by the National Natural Science Foundation of China(12171124,61933007)the Natural Science Foundation of Heilongjiang Province of China(ZD2022F003)+2 种基金the National High-End Foreign Experts Recruitment Plan of China(G2023012004L)the Royal Society of UKthe Alexander von Humboldt Foundation of Germany
文摘In this paper, the problem of cubature Kalman fusion filtering(CKFF) is addressed for multi-sensor systems under amplify-and-forward(AaF) relays. For the purpose of facilitating data transmission, AaF relays are utilized to regulate signal communication between sensors and filters. Here, the randomly varying channel parameters are represented by a set of stochastic variables whose occurring probabilities are permitted to exhibit bounded uncertainty. Employing the spherical-radial cubature principle, a local filter under AaF relays is initially constructed. This construction ensures and minimizes an upper bound of the filtering error covariance by designing an appropriate filter gain. Subsequently, the local filters are fused through the application of the covariance intersection fusion rule. Furthermore, the uniform boundedness of the filtering error covariance's upper bound is investigated through establishing certain sufficient conditions. The effectiveness of the proposed CKFF scheme is ultimately validated via a simulation experiment concentrating on a three-phase induction machine.
基金Supported by Natural Science Foundation of HuBei Province(2022CFB299).
文摘This paper studies the problem of the spectral radius of the uniform hypergraph determined by the signless Laplacian matrix.The upper bound of the spectral radius of a uniform hypergraph is obtained by using Rayleigh principle and the perturbation of the spectral radius under moving the edge operation,and the extremal hypergraphs are characterized for both supertree and unicyclic hypergraphs.The spectral radius of the graph is generalized.
基金supported by the National Natural Science Foundation of China(12125505).
文摘The PICOSEC Micromegas(MM)is a precise timing gaseous detector based on a Cherenkov radiator coupled with a semi-transparent photocathode and an MM amplifying structure.It features a two-stage amplification process that leads to a significant deterioration of non-uniformity when scaling up to larger areas.Since the performance of gaseous detectors is highly dependent on the choice of working gas,optimizing the gas mixture offers a promising solution to improve the uniformity performance.This paper addresses these challenges through a combined approach of simulation based on Garfield++and experimental studies.The simulation investigates the properties of different mixing fractions of gas mixtures and their impact on detector performance,including gain uniformity and time resolution.To verify the simulation results,experimental tests were conducted using a multi-channel PICOSEC MM prototype with different gas mixtures.The experimental results are consistent with the findings of the simulation,indicating that a higher concentration of neon significantly improves the detector’s gain uniformity.Furthermore,the influence of gas mixtures on time resolution was explored as a critical performance indicator.The study presented in this paper offers valuable insights for improving uniformity in large-area PICOSEC MM detectors and optimizing overall performance.
文摘The excimer laser has important applications in many fields. Because of its non-uniform intensity distribution there are some limits in applications. This paper introduces rotational lens array to improve intensity distributions. The intensity variation is reduced to 1 percent by computer simulation.
文摘At our school,we have to wear uniforms every day.The problem is that all my classmates think the uniforms are ugly.We think young people should look smart,because①we would like to wear our own clothes.Our teachers think that if we do that,we will concentrate much②on our clothes than our studies.We don't agree.
基金supported by the National Natural Science Foundation of China(General Program,No.52473331).
文摘With the rapid advancement of 5G communication technology,increasingly stringent demands are placed on the performance and functionality of phase change switches.Given that RF and microwave signals exhibit characteristics of high frequency,high speed,and high precision,it is imperative for phase change switches to possess fast,accurate,and reliable switching capabilities.Moreover,wafer-level compositional homogeneity and resistivity uniformity during semiconductor manufacturing are crucial for ensuring the yield and reliability of RF switches.By controlling magnetron sputter of GeTe through from four key parameters(pressure,power,Ar flow,and post-annealing)and incorporating elemental proportional compensation in the target,we achieved effective modulation over GeTe uniformity.Finally,we successfully demonstrated the process integration of GeTe phase-change RF switches on 6-inch scaled wafers.
文摘The high temporal and spatial coherence of free electron lasers(FELs)reduces the uniformity of the illumination field,leading to scattering effects that blur the edges of patterns,resulting in diminished accuracy and clarity.Traditional imaging models regard the light source as fully incoherent,making it difficult to assess the impact of partially coherent light fields on imaging.If FELs are used in imaging systems,their coherence must be considered.To address this issue,this study explores the relationship between coherence,imaging quality and speckle contrast through a simulation method based on random phases.The method divides the light beam into temporal and spatial coherence cells,analyzes their interactions,and simulates imaging results under different coherence conditions.Additionally,speckle patterns for various illumination modes are calculated to evaluate their effects on speckle contrast and illumination uniformity.The results indicate that under different illumination modes,illumination uniformity decreases as coherence increases,while speckle contrast increases with higher coherence.In terms of imaging quality,higher coherence leads to an increase in both line edge roughness(LER)and line width roughness(LWR),thereby reducing the imaging quality.Additionally,the narrower the line width,the greater the impact of coherence on the imaging quality,resulting in poorer imaging performance.
基金funded by North Carolina Agricultural Foundation(Raleigh,NC,USA)USDA-NIFA(Hatch#02893 and National Needs Fellowship#2019-38420-28970,Washington DC,USA)+1 种基金CJ Bio(Seoul,Korea)CTC Bio(Seoul,Korea)。
文摘Background This study investigated the effects of different non-starch polysaccharide(NSP)sources with NSP degrading enzymes(NSPases)and the influence on the mucosa-associated microbiota and intestinal immunity of nursery pigs,on growth performance and carcass traits at market weight.Methods One hundred and sixty newly weaned pigs at 7.0±0.3 kg body weight(BW)were allotted in a 2×2 factorial with NSP sources and NSPases serving as factors.The 4 dietary treatments were:DDGS,corn distillers'dried grains with solubles as source of NSP;DDGS+NSPases(DDGS+),DDGS with xylanase at 0.01%,3,000 U/kg of feed andβ-mannanase at 0.05%,400 U/kg of feed;SHWB,soybean hulls and wheat bran replacing corn DDGS as the source of NSP;SHWB with NSPases(SHWB+),SHWB with xylanase at 0.01%,3,000 U/kg of feed andβ-mannanase at 0.05%,400 U/kg of feed.Pigs were fed for 37 d and housed in groups of 4 pigs per pen.At d 37,the median body weight pig in each pen was euthanized for sampling to analyze intestinal health parameters.Remaining pigs were fed a common diet for subsequent phases to evaluate the carryover effect on growth and carcass traits.Results The SHWB decreased(P<0.05)the relative abundance of Helicobacter,tended to increase(P=0.074)the relative abundance of Lactobacillus,increased(P<0.05)immunoglobulin G(IgG)in the jejunal mucosa,tended to increase(P=0.096)the villus height(VH)in the jejunum,and tended to improve ADG(P=0.099)and feed efficiency(P=0.068)during phase 1 compared to DDGS treatment.Supplementation of NSPases increased(P<0.05)Shannon index of diversity,increased the relative abundance of Streptococcus and Acinetobacter,and tended to increase(P=0.082)dry matter digestibility.The BW of pigs fed SHWB was more uniform(P<0.05)at the end of the 120 d study.Additionally,hot carcass weight of pigs fed SHWB tended to be more uniform(P=0.089)than DDGS treatment.Conclusion Soybean hulls and wheat bran replacing DDGS in nursery diets improved uniformity of pigs at market weight,which might be attributed to beneficial modulation of the mucosa-associated microbiota and enhanced intestinal morphology during the nursery phase.Supplementation of NSPases had beneficial effects on the intestinal mucosa-associated microbiota,digestibility,and intestinal immunity in SHWB treatment,whereas no carryover effects were overserved at market weight.
基金supported by the National Key Research and Development Program(No.2022YFC2806200)the National Key Research and Development Program(No.2023YFC2810800)the Natural Science Foundation of China(No.52001055).
文摘In this study,the pure erosion behaviour of pure iron and its erosion-corrosion behaviour under different anodic polarization currents were investigated in various cathodic reactions(oxygen reduction,hydrogen ion reduction,and water reduction)using a cylindrical stirring system.The corrosion-enhanced erosion(C-E)rates were determined for each condition.The results revealed that pure iron displayed similar pure erosion behaviour across all three cathodic reactions.When the cathodic reactions involve hydrogen ion reduction or water reduction,the erosion-corrosion of pure iron manifested as uniform damage,with the reduction in hardness being the main cause of the C-E in this case.Conversely,in the case of oxy-gen reduction reaction as the cathodic reaction,the erosion-corrosion presented as pitting damage,with the reduction in hardness resulting from localized concentration of anodic current and the formation of easily worn protruding flaky iron structures at the edges of the pits as the main mechanism of the C-E.Moreover,linear and exponential relationships were found between the C-E rate and the anodic current density for uniform damage and pitting damage,respectively.Finally,the concept of surface equivalent hardness was proposed,along with the establishment of a mathematical model for surface equivalent hardness based on the relationships between the C-E rate and the anodic current density.Utilizing the surface equivalent hardness enables the evaluation of the erosion rate on material surfaces considering the coupled effect.
基金Supported by the Liaoning Provincial Natural Science Foundation(Grant No.2023-MSBA-008)Unveiling and Commanding Program of Liaoning Province(Grant No.2022JH1/10800080)the Fundamental Research Funds for the Central Universities(Grant No.DUT24MS008).
文摘The double-sided lapping process is extensively employed in the manufacturing of wafers,optical windows,and seal rings due to its high efficiency and ability to achieve precise flatness.However,limited research has explored the thickness uniformity among different workpieces after double-sided lapping,and the underlying mechanism remains unclear.To address the demand for higher precision,this paper first analyzed the relative kinematic model between the workpiece and the lapping plate to clarify the causes of thickness variations among workpieces after double-sided lapping.Subsequently,a finite element method(FEM)model was developed to account for the pressure distribution on the workpiece surfaces at the initial stage of the process.The results indicate that the number of workpieces influences the final thickness variation.Then,various sets of thin copper plates with different thicknesses were lapped,and the findings revealed that five copper plates processed simultaneously exhibited more uniform thickness compared to the three plates.The experimental results align well with the theoretical analysis.Ultimately,a thickness variation of less than 6μm was achieved on five copper plates measuringΦ100×2.9 mm.This study presents a comprehensive analysis of the mechanisms influencing thickness uniformity in the double-sided lapping process and provides practical guidelines for optimizing the process to achieve stringent precision standards in industrial applications.
基金financially supported article publication charges under the program"Regional Initiative of Excellence"(RID/SP/0017/2024/01)funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No. 955374。
文摘Background Hatch weight(HW)affects broiler growth and low HW(LHW)often leads to suboptimal performance.Sodium butyrate(SB)has been shown to promote growth through enhanced intestinal health.This study investi-gated how broilers with different HW responded to in ovo SB injection and whether SB could enhance gut health and performance in LHW chicks.Ross 308 broiler eggs were injected on incubation d 12 with physiological saline(control)or SB at 0.1%(SB1),0.3%(SB3),or 0.5%(SB5).Post-hatch,male chicks from each treatment were categorized as high HW(HHW)or LHW and assigned to 8 groups in a 4×2 factorial design.Production parameters were recorded periodically.Intestinal weight,length,and gene expression related to gut barrier function and immune response were examined on d 14 and 42.Cecal microbiota dynamics and predicted functionality were analyzed using 16S rRNA gene sequencing.Results SB treatments did not affect hatchability.HHW-control group exhibited consistently better weight gain and FCR than LHW-control group.SB dose-dependently influenced performance and gut health in both HW catego-ries,with greater effects in LHW broilers at 0.3%.LHW-SB3 group attained highest body weight on d 42,exceeding controls but not significantly differing from HHW-SB3 group.LHW-SB3 group showed upregulation of gut-barrier genes CLDN1 in ileum,TJP1 in jejunum and anti-inflammatory cytokine IL-10 in both jejunum and ileum on d 14.Addi-tionally,LHW-SB3 group upregulated mucin-producing MUC6 gene in ileum,while HHW-SB5 group increased pro-inflammatory IL-12p40 cytokine in caecum on d 42.LHW-SB3 group demonstrated shorter relative intestinal lengths,while HHW-SB5 had longer lengths.HHW-control group had higher bacterial diversity and growth-promoting bacte-ria while LHW-control group harbored the potential pathogen Helicobacter.SB reshaped gut microbiota biodiversity,composition,and predicted metabolic pathways in both HW categories.The LHW-SB3 group exhibited highest alpha diversity on d 14 and most beneficial bacteria at all timepoints.HHW-SB5 group presented increased pathogenic Escherichia-Shigella and Campylobacter on d 42.Conclusions HW significantly affects subsequent performance and SB has differential effects based on HW.LHW chicks benefited more from 0.3%SB,showing improvements in growth,intestinal development,health,and gut microbiota characteristics.
基金supported by the National Natural Science Foundation of China(No.62206143)the Key Research and Development and Promotion Special Project in Henan Province(Nos.222102210141 and 232102211015)。
文摘In this study,we present a unified sparsity-driven framework that significantly enhances motion deblurring performance by integrating two key components:a custom-designed dataset and a low-rank module(LRM).This framework leverages the inherent sparsity of per-pixel blur kernels to bolster both deblurring accuracy and model interpretability.Firstly,we propose an adaptive-basis decomposition-based deblurring(ADD)approach,which constructs a tailored training dataset to enhance the generalization capacity of the deblurring network.The ADD framework adaptively decomposes motion blur into sparse basis elements,effectively addressing the intricacies associated with non-uniform blurs.Secondly,an LRM is proposed to improve the interpretability of deblurring models as a plug-and-play module,primarily designed to identify and harness the intrinsic sparse features in sharp images.A series of ablation studies have been conducted to substantiate the synergistic advantages of combining the proposed ADD with the LRM for overall improvement in deblurring efficacy.Subsequently,we empirically demonstrate through rigorous experimentation that incorporating the LRM into an existing Uformer network leads to substantial enhancement in reconstruction performance.This integration yields a sparsity-guided low-rank network(SGLRN).Operating under the overarching principle of sparsity,SGLRN consistently outperforms state-of-the-art methods across multiple standard deblurring benchmarks.Comprehensive experimental results,assessed through quantitative metrics and qualitative visual evaluations,provide compelling evidence of its effectiveness.The overall deblurring results are available at Google Drive.
基金Supported by Science and Technology Fund for Basic Research of Guizhou Province([2020]1Y010)National Nature Sciences Foundation of China(11901260,12071096,12501342)Specialized Fund for the Doctoral Development of Kaili University(BS202502028)。
文摘The upper bound on the model error will be decreased when the mean square error and the maximum distance deviation are sufficiently small in the uniform designs for mixture experiments and the design is more robust for the model.However,the analytical expressions of MSED and MD are currently only available in the hypercube,but both types of deviations in other studies are just approximations.Although it can obtain good approximations in the low-dimensional case,the calculation will be more complicated for an experiment with more variables.Therefore,in this paper,an algorithm based on lattice point partitioning design is proposed to obtain the analytical expression of the MSED and MD in the region covered by the lattice points.Furthermore,the design’s optimality is considered and illustrated by examples under the same uniformity.
基金Supported by the Higher Education Science Research Project(Natural Science)of Anhui Province(Grant No.2023AH050487)。
文摘In this paper,we introduce a new geometric constant R_(X)(κ)based on isosceles orthogonality.First,we explore some basic properties of this new constant and then provide several examples to estimate its exact values in certain specific Banach spaces.Next,we investigate the relationships between this new constant and other classical constants.Specifically,we establish an inequality relationship between it and the J(X)constant,as well as an identity relationship between it and theρX(t)constant.Furthermore,we characterize some geometric properties of Banach spaces by means of this new constant.Finally,by restricting the above-mentioned constant to the unit sphere,we introduce another new constant,calculate its upper and lower bounds,and present a relevant example.
文摘Scour around bridge pier foundations is a complex phenomenon that can threaten structural stability.Accurate prediction of scour depth around compound piers remains challenging for bridge engineers.This study investigated the effect of foundation elevation on scour around compound piers and developed reliable scour depth prediction models for economical foundation design.Experiments were conducted under clear-water conditions using two circular piers:(1)a uniform pier(with a diameter of D)and(2)a compound pier consisting of a uniform pier resting on a circular foundation(with a foundation diameter(D_(f))of 2D)positioned at various elevations(Z)relative to the channel bed.Results showed that foundation elevation significantly affected scour depth.Foundations at or below the bed(Z/D≥0)reduced scour,while those projecting into the flow field(Z/D<0)increased scour.The optimal foundation elevation was found to be 0.1D below the bed level,yielding a 57%reduction in scour depth compared to the uniform pier due to its shielding effect against downflow and horseshoe vortices.In addition,regression,artificial neural network(ANN),and M5 model tree models were developed using experimental data from this and previous studies.The M5 model outperformed the traditional HEC-18 equation,regression,and ANN models,with a coefficient of determination greater than 0.85.Sensitivity analysis indicated that flow depth,foundation elevation,and diameter significantly influenced scour depth prediction,whereas sediment size had a lesser impact.
基金supported by National Natural Science Foundation of China(No.524B2078,12426307,51906203)Guangdong Major Project of Basic and Applied Basic Research(2023B0303000002)+6 种基金Guangdong Basic and Applied Basic Research Foundation(2023B1515120005)Natural Science Foundation of Shenzhen(JCYJ20241202125327036,JCYJ20240813100103005)Shenzhen Engineering Research Center of Redox Flow Battery for Energy Storage(XMHT20230208003)Research Project on Medium-and Long-Duration Flow Battery Energy Storage Technology(2024KJTW0015)China Association for Science and Technology(OR2308010)High level of special funds(G03034K001)supported by the Center for Computational Science and Engineering at the Southern University of Science and Technology.
文摘Long-duration energy storage has become critical for renewable energy integration.While redox flow batteries,especially vanadium-based systems,are scaling up in capacity,their performance at the stack level remains insufficiently optimized,demanding more profound mechanistic studies and engineering refinements.To address the difficulties in resolving the flow inhomogeneity at the stack scale,this study establishes a multi-physics field coupling model and analyzes the pressure distributions,flow rate differences,active substance concentration,and electrochemical characteristics.The results show that the uneven cell pressure distribution is a key factor affecting the consistency of the system performance,and the increase in the flow rate improves the reactant homogeneity,with both the average concentration and the uniformity factor increasing with the flow rate.In contrast,high current densities lead to an increased imbalance between electrochemical depletion and reactant replenishment,resulting in a significant decrease in reactant concentration in the under-ribs region.In addition,a higher flow rate can expand the high-current-density region where the stack operates efficiently.This study provides a theoretical basis for optimizing the design of the stack components.
基金support of Natural Science Foundation of China(Grant No.52108324,No.52008207,and No.52108298)for conducting this study.
文摘The mineralization process of microbial-induced calcium carbonate precipitation(MICP)is influenced by many factors,and the uniformity of the calcium carbonate precipitation has become the main focus and challenge for MICP technology.In this study,the uniformity of the saturated calcareous sand treated with MICP was in-vestigated through one-dimensional calcareous sand column tests and model tests.The coefficient of variation was employed in one-dimensional sand column tests to investigate the impact of injection rate,cementation solution concentration,and number of injection cycles on the uniformity of the MICP treatment.Additionally,model tests were conducted to investigate the impact of injection pressure and methods on the treatment range and uniformity under three-dimensional seepage conditions.Test results demonstrate that the reinforcement strength and uniformity are significantly influenced by the injection rate of the cementation solution,with a rate of 3 mL/min,yielding a favorable treatment effect.Excessive concentration of the cementation solution can lead to significant non-uniformity and a reduction in the compressive strength of MICP-treated samples.Conversely,excessively low concentrations may result in decreased bonding efficiency.Among the four considered con-centrations,0.5 mol/L and 1 mol/L exhibit superior reinforcing effects.The morphological development of calcareous sandy foundation reinforcement is associated with the spatial distribution pattern of the bacterial solution,exhibiting a relatively larger reinforcement area in proximity to the lower region of the model and a gradually decreasing range towards the upper part.Under three-dimensional seepage conditions,in addition to the non-uniform radial cementation along the injection pipe,there is also vertical heterogeneity of cementation along the length of the injection pipe due to gravitational effects,resulting in preferential deposition of calcium carbonate at the lower section,The application of injection pressure and a double-pipe circulation injection method can mitigate the accumulation of bacterial solution and cementation solution at the bottom,thereby improving the reinforcement range and uniformity.
