In this paper,vibration analysis of functionally graded porous beams is carried out using the third-order shear deformation theory.The beams have uniform and non-uniform porosity distributions across their thickness a...In this paper,vibration analysis of functionally graded porous beams is carried out using the third-order shear deformation theory.The beams have uniform and non-uniform porosity distributions across their thickness and both ends are supported by rotational and translational springs.The material properties of the beams such as elastic moduli and mass density can be related to the porosity and mass coefficient utilizing the typical mechanical features of open-cell metal foams.The Chebyshev collocation method is applied to solve the governing equations derived from Hamilton's principle,which is used in order to obtain the accurate natural frequencies for the vibration problem of beams with various general and elastic boundary conditions.Based on the numerical experiments,it is revealed that the natural frequencies of the beams with asymmetric and non-uniform porosity distributions are higher than those of other beams with uniform and symmetric porosity distributions.展开更多
Barley(Hordeum vulgare L.)ranks as the fourth most cultivated cereal crop globally by planting area.Kernel characteristics,including grain length,grain width,and thousand-grain weight(TGW),are essential determinants o...Barley(Hordeum vulgare L.)ranks as the fourth most cultivated cereal crop globally by planting area.Kernel characteristics,including grain length,grain width,and thousand-grain weight(TGW),are essential determinants of barley yield and quality.The identification and cloning of genes related to kernel traits,along with the detection of superior alleles,are fundamental for marker-assisted selection in barley breeding.This study presents the cloning of HvGL7-2H from barley,based on the known rice GL7 gene.The functional significance of HvGL7-2H in grain length was confirmed through ethyl methane sulfonate(EMS)mutants of the barley landrace“Hatiexi”.A candidate gene-based association analysis was conducted using a panel of 363 barley accessions to identify superior haplotypes for HvGL7-2H.The analysis revealed that Hap3 represented the superior haplotype for both grain length and TGW,while Hap4 emerged as the superior haplotype for TGW.These findings indicate that genotypes carrying the superior allele serve as valuable genetic resources,and the molecular markers identified herein will facilitate grain size and yield improvement in barley breeding programs.展开更多
The problem of the robust D-stability analysis for linear systems with parametric uncertainties is addressed. For matrix polytopes, new conditions via the affine parameter-dependent Lyapunov function of uncertain syst...The problem of the robust D-stability analysis for linear systems with parametric uncertainties is addressed. For matrix polytopes, new conditions via the affine parameter-dependent Lyapunov function of uncertain systems are developed with the benefit of the scalar multi-convex function. To be convenient for applications, such conditions are simplified into new linear matrix inequality （LMI） conditions, which can be solved by the powerful LMI toolbox. Numerical examples are provided to indicate that this new approach is less conservative than previous results for Hurwitz stability, Schur stability and D-stability of uncertain systems under certain circumstances.展开更多
Panicle swarm optimization （PSO） is an optimization algorithm based on the swarm intelligent principle. In this paper the modified PSO is applied to a kernel principal component analysis （ KPCA ） for an optimal ke...Panicle swarm optimization （PSO） is an optimization algorithm based on the swarm intelligent principle. In this paper the modified PSO is applied to a kernel principal component analysis （ KPCA ） for an optimal kernel function parameter. We first comprehensively considered within-class scatter and between-class scatter of the sample features. Then, the fitness function of an optimized kernel function parameter is constructed, and the particle swarm optimization algorithm with adaptive acceleration （CPSO） is applied to optimizing it. It is used for gearbox condi- tion recognition, and the result is compared with the recognized results based on principal component analysis （PCA）. The results show that KPCA optimized by CPSO can effectively recognize fault conditions of the gearbox by reducing bind set-up of the kernel function parameter, and its results of fault recognition outperform those of PCA. We draw the conclusion that KPCA based on CPSO has an advantage in nonlinear feature extraction of mechanical failure, and is helpful for fault condition recognition of complicated machines.展开更多
We add new modules for receiver function （RF） analysis in SplitLab toolbox, which includes the manual RF analysis module, automatic RF analysis and related quality control modules, and H-k stacking module. The updat...We add new modules for receiver function （RF） analysis in SplitLab toolbox, which includes the manual RF analysis module, automatic RF analysis and related quality control modules, and H-k stacking module. The updated toolbox （named SplitRFLab toolbox）, espe- cially its automatic RF analysis module, could calculate the RFs quickly and efficiently, which is very useful in RF analysis with huge amount of seismic data. China is now conducting the ChinArray project that plans to deploy thousands of portable stations across Chinese mainland. Our SplitRFLab toolbox may obtain reliable RF results quickly at the first time, which provide essentially new constraint to the crustal and mantle structures.展开更多
Returning to moon has become a top topic recently. Many studies have shown that soft landing is a challenging problem in lunar exploration. The lunar soft landing in this paper begins from a 100 km circular lunar park...Returning to moon has become a top topic recently. Many studies have shown that soft landing is a challenging problem in lunar exploration. The lunar soft landing in this paper begins from a 100 km circular lunar parking orbit. Once the landing area has been selected and it is time to deorbit for landing, a ΔV burn of 19.4 m/s is performed to establish a 100×15 km elliptical orbit. At perilune, the landing jets are ignited, and a propulsive landing is performed. A guidance and control scheme for lunar soft landing is proposed in the paper, which combines optimal theory with nonlinear neuro-control. Basically, an optimal nonlinear control law based on artificial neural network is presented, on the basis of the optimum trajectory from perilune to lunar surface in terms of Pontryagin's maximum principle according to the terminal boundary conditions and performance index. Therefore some optimal control laws can be carried out in the soft landing system due to the nonlinear mapping function of the neural network. The feasibility and validity of the control laws are verified in a simulation experiment.展开更多
Trichomes are specialized structures that originate from epidermal cells of organs in higher plants.The cotton fiber is a unique single-celled trichome that elongates from the seed coat epidermis.Cotton(Gossypium hirs...Trichomes are specialized structures that originate from epidermal cells of organs in higher plants.The cotton fiber is a unique single-celled trichome that elongates from the seed coat epidermis.Cotton(Gossypium hirsutum)fibers and trichomes are models for cell differentiation.In an attempt to elucidate the intercellular factors that regulate fiber and trichome cell development,we identified a plasmodesmal β-1,3-glucanase gene(designated GhPdBG)controlling the opening and closing of plasmodesmata in cotton fibers.Structural and evolutionary analysis showed haplotypic variation in the promoter region of the GhPdBG gene among 352 cotton accessions,but high conservation in the coding region.GhPdBG was expressed predominantly in cotton fibers and localized to plasmodesmata(PD).Expression patterns of PdBG that corresponded to PD permeability were apparent during fiber development in G.hirsutum and G.barbadense.The PdBG-mediated opening-closure of PD appears to be involved in fiber development and may account for the contrasting fiber traits of these two species.Ectopic expression of GhPdBG revealed that it functions in regulating fiber and trichome length and/or density by modulating plasmodesmatal permeability.This finding suggests that plasmodesmal targeting of GhPdBG,as a switch of intercellular channels,regulates single-celled fiber and trichome development in cotton.展开更多
The first step in the analysis of high-throughput experiment results is often to identify genes orproteins with certain characteristics, such as genes being differentially expressed (DE). To gainmore insights into the...The first step in the analysis of high-throughput experiment results is often to identify genes orproteins with certain characteristics, such as genes being differentially expressed (DE). To gainmore insights into the underlying biology, functional enrichment analysis is then conductedto provide functional interpretation for the identified genes or proteins. The hypergeometricP value has been widely used to investigate whether genes from predefined functional terms,e.g., Reactome, are enriched in the DE genes. The hypergeometric P value has several limitations: (1) computed independently for each term, thus neglecting biological dependence;(2) subject to a size constraint that leads to the tendency of selecting less-specific terms. In this paper,a Bayesian approach is proposed to overcome these limitations by incorporating the interconnected dependence structure of biological functions in the Reactome database through a CARprior in a Bayesian hierarchical logistic model. The inference on functional enrichment is thenbased on posterior probabilities that are immune to the size constraint. This method can detectmoderate but consistent enrichment signals and identify sets of closely related and biologicallymeaningful functional terms rather than isolated terms. The performance of the Bayesian methodis demonstrated via a simulation study and a real data application.展开更多
The manuscript reviews the history and quo of the theory of Timoshenko’s method in stability analysis of compressive levers first, taking an example to explain the m-simulation method and putting forward the 3rd-7th ...The manuscript reviews the history and quo of the theory of Timoshenko’s method in stability analysis of compressive levers first, taking an example to explain the m-simulation method and putting forward the 3rd-7th boundary conditions demonstrating their superiorities in improving the precision through examples, followed by proposing and applying the join conditions in the stability analysis of combined axial force compressive levers gaining success. Through a brief example showing the effect of some related theories in a simple structural stability analysis, its application prospect is discussed.展开更多
Generalized Jacobi polynomials with indexes α,β∈ R are introduced and some basic properties are established. As examples of applications,the second- and fourth-order elliptic boundary value problems with Dirichlet ...Generalized Jacobi polynomials with indexes α,β∈ R are introduced and some basic properties are established. As examples of applications,the second- and fourth-order elliptic boundary value problems with Dirichlet or Robin boundary conditions are considered,and the generalized Jacobi spectral schemes are proposed. For the diagonalization of discrete systems,the Jacobi-Sobolev orthogonal basis functions are constructed,which allow the exact solutions and the approximate solutions to be represented in the forms of infinite and truncated Jacobi series. Error estimates are obtained and numerical results are provided to illustrate the effectiveness and the spectral accuracy.展开更多
In this paper,based on simplified Boltzmann equation,we explore the inverse-design of mesoscopic models for compressible flow using the Chapman-Enskog analysis.Starting from the single-relaxation-time Boltzmann equati...In this paper,based on simplified Boltzmann equation,we explore the inverse-design of mesoscopic models for compressible flow using the Chapman-Enskog analysis.Starting from the single-relaxation-time Boltzmann equation with an additional source term,two model Boltzmann equations for two reduced distribution functions are obtained,each then also having an additional undetermined source term.Under this general framework and using Navier-Stokes-Fourier(NSF)equations as constraints,the structures of the distribution functions are obtained by the leading-order Chapman-Enskog analysis.Next,five basic constraints for the design of the two source terms are obtained in order to recover the NSF system in the continuum limit.These constraints allow for adjustable bulk-to-shear viscosity ratio,Prandtl number as well as a thermal energy source.The specific forms of the two source terms can be determined through proper physical considerations and numerical implementation requirements.By employing the truncated Hermite expansion,one design for the two source terms is proposed.Moreover,three well-known mesoscopic models in the literature are shown to be compatible with these five constraints.In addition,the consistent implementation of boundary conditions is also explored by using the Chapman-Enskog expansion at the NSF order.Finally,based on the higher-order Chapman-Enskog expansion of the distribution functions,we derive the complete analytical expressions for the viscous stress tensor and the heat flux.Some underlying physics can be further explored using the DNS simulation data based on the proposed model.展开更多
This work uses isogeometric analysis(IGA),which is based on nonlocal hypothesis and higher-order shear beam hypothesis,to investigate the static bending and free oscillation of a magneto-electro-elastic functionally g...This work uses isogeometric analysis(IGA),which is based on nonlocal hypothesis and higher-order shear beam hypothesis,to investigate the static bending and free oscillation of a magneto-electro-elastic functionally graded(MEE-FG)nanobeam subject to elastic boundary constraints(BCs).The magneto-electric boundary condition and the Maxwell equation are used to calculate the variation of electric and magnetic potentials along the thickness direction of the nanobeam.This study is innovative since it does not use the conventional boundary conditions.Rather,an elastic system of straight and torsion springs with controllable stiffness is used to support nanobeams’beginning and end positions,creating customizable BCs.The governing equations of motion of nanobeams are established by applying Hamilton’s principle and IGA is used to determine deflections and natural frequency values.Verification studies were performed to evaluate the convergence and accuracy of the proposed method.Aside from this,the impact of the input parameters on the static bending and free oscillation of the MEE-FG nanobeam is examined in detail.These findings could be valuable for analyzing and designing innovative structures constructed of functionally graded MEE materials.展开更多
文摘In this paper,vibration analysis of functionally graded porous beams is carried out using the third-order shear deformation theory.The beams have uniform and non-uniform porosity distributions across their thickness and both ends are supported by rotational and translational springs.The material properties of the beams such as elastic moduli and mass density can be related to the porosity and mass coefficient utilizing the typical mechanical features of open-cell metal foams.The Chebyshev collocation method is applied to solve the governing equations derived from Hamilton's principle,which is used in order to obtain the accurate natural frequencies for the vibration problem of beams with various general and elastic boundary conditions.Based on the numerical experiments,it is revealed that the natural frequencies of the beams with asymmetric and non-uniform porosity distributions are higher than those of other beams with uniform and symmetric porosity distributions.
基金financially supported by the National Natural Science Foundation of China(31771774)the National Key Research and Development Program of China(2018YFD1000700 and 2018YFD1000706)+1 种基金the Young Top-notch Talent Cultivation Program of Hubei Province,Hubei Hongshan Laboratory,Chinathe China Agriculture Research System of Ministry of Agriculture and Rural Affairs(CARS-05).
文摘Barley(Hordeum vulgare L.)ranks as the fourth most cultivated cereal crop globally by planting area.Kernel characteristics,including grain length,grain width,and thousand-grain weight(TGW),are essential determinants of barley yield and quality.The identification and cloning of genes related to kernel traits,along with the detection of superior alleles,are fundamental for marker-assisted selection in barley breeding.This study presents the cloning of HvGL7-2H from barley,based on the known rice GL7 gene.The functional significance of HvGL7-2H in grain length was confirmed through ethyl methane sulfonate(EMS)mutants of the barley landrace“Hatiexi”.A candidate gene-based association analysis was conducted using a panel of 363 barley accessions to identify superior haplotypes for HvGL7-2H.The analysis revealed that Hap3 represented the superior haplotype for both grain length and TGW,while Hap4 emerged as the superior haplotype for TGW.These findings indicate that genotypes carrying the superior allele serve as valuable genetic resources,and the molecular markers identified herein will facilitate grain size and yield improvement in barley breeding programs.
基金supported by the National Natural Science Foundation of China (6090405161021002)
文摘The problem of the robust D-stability analysis for linear systems with parametric uncertainties is addressed. For matrix polytopes, new conditions via the affine parameter-dependent Lyapunov function of uncertain systems are developed with the benefit of the scalar multi-convex function. To be convenient for applications, such conditions are simplified into new linear matrix inequality （LMI） conditions, which can be solved by the powerful LMI toolbox. Numerical examples are provided to indicate that this new approach is less conservative than previous results for Hurwitz stability, Schur stability and D-stability of uncertain systems under certain circumstances.
基金supported by National Natural Science Foundation under Grant No.50875247Shanxi Province Natural Science Foundation under Grant No.2009011026-1
文摘Panicle swarm optimization （PSO） is an optimization algorithm based on the swarm intelligent principle. In this paper the modified PSO is applied to a kernel principal component analysis （ KPCA ） for an optimal kernel function parameter. We first comprehensively considered within-class scatter and between-class scatter of the sample features. Then, the fitness function of an optimized kernel function parameter is constructed, and the particle swarm optimization algorithm with adaptive acceleration （CPSO） is applied to optimizing it. It is used for gearbox condi- tion recognition, and the result is compared with the recognized results based on principal component analysis （PCA）. The results show that KPCA optimized by CPSO can effectively recognize fault conditions of the gearbox by reducing bind set-up of the kernel function parameter, and its results of fault recognition outperform those of PCA. We draw the conclusion that KPCA based on CPSO has an advantage in nonlinear feature extraction of mechanical failure, and is helpful for fault condition recognition of complicated machines.
基金supported by China National Special Fund for Earthquake Scientific Research in Public Interest(201008001,201308011)
文摘We add new modules for receiver function （RF） analysis in SplitLab toolbox, which includes the manual RF analysis module, automatic RF analysis and related quality control modules, and H-k stacking module. The updated toolbox （named SplitRFLab toolbox）, espe- cially its automatic RF analysis module, could calculate the RFs quickly and efficiently, which is very useful in RF analysis with huge amount of seismic data. China is now conducting the ChinArray project that plans to deploy thousands of portable stations across Chinese mainland. Our SplitRFLab toolbox may obtain reliable RF results quickly at the first time, which provide essentially new constraint to the crustal and mantle structures.
文摘Returning to moon has become a top topic recently. Many studies have shown that soft landing is a challenging problem in lunar exploration. The lunar soft landing in this paper begins from a 100 km circular lunar parking orbit. Once the landing area has been selected and it is time to deorbit for landing, a ΔV burn of 19.4 m/s is performed to establish a 100×15 km elliptical orbit. At perilune, the landing jets are ignited, and a propulsive landing is performed. A guidance and control scheme for lunar soft landing is proposed in the paper, which combines optimal theory with nonlinear neuro-control. Basically, an optimal nonlinear control law based on artificial neural network is presented, on the basis of the optimum trajectory from perilune to lunar surface in terms of Pontryagin's maximum principle according to the terminal boundary conditions and performance index. Therefore some optimal control laws can be carried out in the soft landing system due to the nonlinear mapping function of the neural network. The feasibility and validity of the control laws are verified in a simulation experiment.
基金the State Key Laboratory of Cotton Biology Open Fund(CB2021A04)the Agricultural Seed Project of Shandong Province(2020LZGC002)the Science Foundation of Shandong Province(ZR2020MC107)。
文摘Trichomes are specialized structures that originate from epidermal cells of organs in higher plants.The cotton fiber is a unique single-celled trichome that elongates from the seed coat epidermis.Cotton(Gossypium hirsutum)fibers and trichomes are models for cell differentiation.In an attempt to elucidate the intercellular factors that regulate fiber and trichome cell development,we identified a plasmodesmal β-1,3-glucanase gene(designated GhPdBG)controlling the opening and closing of plasmodesmata in cotton fibers.Structural and evolutionary analysis showed haplotypic variation in the promoter region of the GhPdBG gene among 352 cotton accessions,but high conservation in the coding region.GhPdBG was expressed predominantly in cotton fibers and localized to plasmodesmata(PD).Expression patterns of PdBG that corresponded to PD permeability were apparent during fiber development in G.hirsutum and G.barbadense.The PdBG-mediated opening-closure of PD appears to be involved in fiber development and may account for the contrasting fiber traits of these two species.Ectopic expression of GhPdBG revealed that it functions in regulating fiber and trichome length and/or density by modulating plasmodesmatal permeability.This finding suggests that plasmodesmal targeting of GhPdBG,as a switch of intercellular channels,regulates single-celled fiber and trichome development in cotton.
基金This work has been supported in part by National Institutes of Health(NIH)[grant number 1R15HG006365-01]National Science Foundation(NSF)[grant number IIS-1302564].
文摘The first step in the analysis of high-throughput experiment results is often to identify genes orproteins with certain characteristics, such as genes being differentially expressed (DE). To gainmore insights into the underlying biology, functional enrichment analysis is then conductedto provide functional interpretation for the identified genes or proteins. The hypergeometricP value has been widely used to investigate whether genes from predefined functional terms,e.g., Reactome, are enriched in the DE genes. The hypergeometric P value has several limitations: (1) computed independently for each term, thus neglecting biological dependence;(2) subject to a size constraint that leads to the tendency of selecting less-specific terms. In this paper,a Bayesian approach is proposed to overcome these limitations by incorporating the interconnected dependence structure of biological functions in the Reactome database through a CARprior in a Bayesian hierarchical logistic model. The inference on functional enrichment is thenbased on posterior probabilities that are immune to the size constraint. This method can detectmoderate but consistent enrichment signals and identify sets of closely related and biologicallymeaningful functional terms rather than isolated terms. The performance of the Bayesian methodis demonstrated via a simulation study and a real data application.
文摘The manuscript reviews the history and quo of the theory of Timoshenko’s method in stability analysis of compressive levers first, taking an example to explain the m-simulation method and putting forward the 3rd-7th boundary conditions demonstrating their superiorities in improving the precision through examples, followed by proposing and applying the join conditions in the stability analysis of combined axial force compressive levers gaining success. Through a brief example showing the effect of some related theories in a simple structural stability analysis, its application prospect is discussed.
基金the National Natural Science Foundation of China (Nos.11571238,11601332,91130014,11471312 and 91430216).
文摘Generalized Jacobi polynomials with indexes α,β∈ R are introduced and some basic properties are established. As examples of applications,the second- and fourth-order elliptic boundary value problems with Dirichlet or Robin boundary conditions are considered,and the generalized Jacobi spectral schemes are proposed. For the diagonalization of discrete systems,the Jacobi-Sobolev orthogonal basis functions are constructed,which allow the exact solutions and the approximate solutions to be represented in the forms of infinite and truncated Jacobi series. Error estimates are obtained and numerical results are provided to illustrate the effectiveness and the spectral accuracy.
基金supported by the U.S.National Science Foundation(CNS-1513031,CBET-1706130)the National Natural Science Foundation of China(91852205,91741101&11961131006)+1 种基金the National Numerical Wind Tunnel program,Guangdong Provincial Key Laboratory of Turbulence Research and Applications(2019B21203001)Shenzhen Science&Technology Program(Grant No.KQTD20180411143441009).
文摘In this paper,based on simplified Boltzmann equation,we explore the inverse-design of mesoscopic models for compressible flow using the Chapman-Enskog analysis.Starting from the single-relaxation-time Boltzmann equation with an additional source term,two model Boltzmann equations for two reduced distribution functions are obtained,each then also having an additional undetermined source term.Under this general framework and using Navier-Stokes-Fourier(NSF)equations as constraints,the structures of the distribution functions are obtained by the leading-order Chapman-Enskog analysis.Next,five basic constraints for the design of the two source terms are obtained in order to recover the NSF system in the continuum limit.These constraints allow for adjustable bulk-to-shear viscosity ratio,Prandtl number as well as a thermal energy source.The specific forms of the two source terms can be determined through proper physical considerations and numerical implementation requirements.By employing the truncated Hermite expansion,one design for the two source terms is proposed.Moreover,three well-known mesoscopic models in the literature are shown to be compatible with these five constraints.In addition,the consistent implementation of boundary conditions is also explored by using the Chapman-Enskog expansion at the NSF order.Finally,based on the higher-order Chapman-Enskog expansion of the distribution functions,we derive the complete analytical expressions for the viscous stress tensor and the heat flux.Some underlying physics can be further explored using the DNS simulation data based on the proposed model.
文摘This work uses isogeometric analysis(IGA),which is based on nonlocal hypothesis and higher-order shear beam hypothesis,to investigate the static bending and free oscillation of a magneto-electro-elastic functionally graded(MEE-FG)nanobeam subject to elastic boundary constraints(BCs).The magneto-electric boundary condition and the Maxwell equation are used to calculate the variation of electric and magnetic potentials along the thickness direction of the nanobeam.This study is innovative since it does not use the conventional boundary conditions.Rather,an elastic system of straight and torsion springs with controllable stiffness is used to support nanobeams’beginning and end positions,creating customizable BCs.The governing equations of motion of nanobeams are established by applying Hamilton’s principle and IGA is used to determine deflections and natural frequency values.Verification studies were performed to evaluate the convergence and accuracy of the proposed method.Aside from this,the impact of the input parameters on the static bending and free oscillation of the MEE-FG nanobeam is examined in detail.These findings could be valuable for analyzing and designing innovative structures constructed of functionally graded MEE materials.
