The solid particle impurities generated by pipe wall corrosion might deposit at the elbow of hilly pipelines during the production shutdown of oil pipelines.These solid particle impurities will seriously affect the sa...The solid particle impurities generated by pipe wall corrosion might deposit at the elbow of hilly pipelines during the production shutdown of oil pipelines.These solid particle impurities will seriously affect the safety of the pipeline operation and the quality of the petroleum products.Thus,it is necessary to study the methods of removing these trapped particles from pipelines.At present,the most common way to remove these solid particle impurities is pigging oil pipelines periodically by utilizing the mechanical pigging method,while the frequent pigging operation will increase the cost and risk of pipeline operation.It is very convenient and economical to remove the accumulated particles out from the pipeline by oil stream,which can be named Hydraulic Pigging Method(HPM).However,the behavior mechanism of particle in flowing oil is still unclear.This motivates the present research on the particles flushed out by the flowing oil.A numerical model governing the trapped particles displacement from the elbow of an inclined oil pipeline is established in the Euler-Lagrangian framework.The simulation is achieved via CFD coupling with DEM.The CFD method is employed to solving the continuous phase flow,while the discrete particle phase is tracked by the DEM.The numerical model is first validated by comparison with results taken from the published literature.From the simulation results,it is observed that the oil stream,carrier phase,can only flush out the solid particles in a certain diameter range under the given operation conditions,and the particles whose diameter beyond that diameter range will cannot be removed out from the pipeline.The influence of the pipe inclined angle,the oil bulk velocity and the particle diameter on the particle migration characteristics is examined in detail.Furthermore,in order to enhance the efficiency of HPM,an Enhanced Hydraulic Pigging Method based on Multi-Physical Field Collaboration(EHPM-MPFC)is also proposed in the present work.The EHPM-MPFC is validated for having high pigging efficiency via the comparison of the migration characteristics of particles during the EHPM-MPFC and HPM process.The present results can provide the guidance to the HPM operation of products pipelines.展开更多
Based on the modified couple-stress theory,the three-dimensional(3D)bending deformation and vibration responses of simply-supported and multilayered twodimensional(2D)decagonal quasicrystal(QC)nanoplates are investiga...Based on the modified couple-stress theory,the three-dimensional(3D)bending deformation and vibration responses of simply-supported and multilayered twodimensional(2D)decagonal quasicrystal(QC)nanoplates are investigated.The surface loading is assumed to be applied on the top surface in the bending analysis,the tractionfree boundary conditions on both the top and bottom surfaces of the nanoplates are used in the free vibration analysis,and a harmonic concentrated point loading is applied on the top surfaces of the nanoplates in the harmonic response analysis.The general solutions of the extended displacement and traction vectors for the homogeneous QC nanoplates are derived by solving the eigenvalue problem reduced from the final governing equations of motion with the modified couple-stress effect.By utilizing the propagator matrix method,the analytical solutions of the displacements of bending deformation for the phonon and phason fields,the natural frequency of free vibration,and the displacements of the harmonic responses of the phonon and phason fields are obtained.Numerical examples are illustrated to show the effects of the quasiperiodic direction,the material length scale parameter,and the the stacking sequence of the nanoplates on the bending deformation and vibration responses of two sandwich nanoplates made of QC and crystal materials.展开更多
The phase stability,magnetic properties,martensitic transformation,and electronic properties of the Ni_(2−x)Mn_(1+x+y)Sn_(1−y) system with excess Mn have been systematically investigated by the first-principles calcul...The phase stability,magnetic properties,martensitic transformation,and electronic properties of the Ni_(2−x)Mn_(1+x+y)Sn_(1−y) system with excess Mn have been systematically investigated by the first-principles calculations.Results indicate that the excess Mn atoms will directly occupy the sublattices of Ni(MnNi)or Sn(MnSn).The formation energy(Ef)of the austenite has a relationship with the Mn content:Ef=135.27(1+x+y)−293.01,that is,the phase stability of the austenite decreases gradually with the increase in Mn content.According to the results of the formation energy of austenite,there is an antiparallel arrangement of the magnetic moment between the excess and normal Mn atoms in the Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x=0 or y=0)system,while the magnetic moment direction of the normal Mn atoms arranges antiparallel to that of MnNi atoms and parallel to that of MnSn atoms in the Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x,y≠0)system.The martensitic transformation occurs in some Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x,y≠0)alloys with large magnetic moments of ferrimagnetic austenite.Besides,the valence electrons tend to distribute around the Ni or MnNi atoms and mainly bond with the normal Mn atoms.The results of this work can lay a theoretical foundation for further development of the Ni_(2−x)Mn_(1+x+y)Sn_(1−y) system as the potential ferromagnetic shape memory alloys.展开更多
The all-d-metal Ni-Mn-Ti Heusler alloy has giant elastocaloric eff ect and excellent mechanical properties,which is diff erent from the conventional Ni-Mn-based Heusler alloys.In this work,the preferred site occupatio...The all-d-metal Ni-Mn-Ti Heusler alloy has giant elastocaloric eff ect and excellent mechanical properties,which is diff erent from the conventional Ni-Mn-based Heusler alloys.In this work,the preferred site occupation,phase stability,martensitic transformation,magnetic properties,and electronic structure of the B-doped Ni_(2)Mn_(1.5)Ti_(0.5)alloys are systematically investigated by the fi rst-principles calculations.The results show that B atoms preferentially occupy the octahedral interstitial.The doped B atoms tend to exist in the(Ni_(2)Mn_(1.5)Ti_(0.5))_(1-x)B_(x)(x=0.03,0.06,0.09)alloy in the form of aggregation distribution,and the martensitic transformation temperature decreases with the increase in the B content.For octahedral interstitial doping,the toughness and plasticity of the(Ni_(2)Mn_(1.5)Ti_(0.5))_(1-x)B_(x) alloys decrease,but the strength and rigidity are greatly enhanced.This is because a small part of the d-d hybridization in ternary Ni-Mn-Ti alloy is replaced by the p-d hybridization in Ni-Mn-Ti-B alloy.展开更多
Although root nodules are essential for biological nitrogen fixation in legumes,the cell types and molecular regulatory mechanisms contributing to nodule development and nitrogen fixation in determinate nodule legumes...Although root nodules are essential for biological nitrogen fixation in legumes,the cell types and molecular regulatory mechanisms contributing to nodule development and nitrogen fixation in determinate nodule legumes,such as soybean(Glycine max),remain incompletely understood.Here,we generated a single-nucleus resolution transcriptomic atlas of soybean roots and nodules at 14 days post inoculation(dpi)and annotated 17 major cell types,including six that are specific to nodules.We identified the specific cell types responsible for each step in the ureides synthesis pathway,which enables spatial compartmentalization of biochemical reactions during soybean nitrogen fixation.By utilizing RNA velocity analysis,we reconstructed the differentiation dynamics of soybean nodules,which differs from those of indeterminate nodules in Medicago truncatula.Moreover,we identified several putative regulators of soybean nodulation and two of these genes,GmbHLH93 and GmSCL1,were as-yet uncharacterized in soybean.Overexpression of each gene in soybean hairy root systems validated their respective roles in nodulation.Notably,enrichment for cytokinin-related genes in soybean nodules led to identification of the cytokinin receptor,GmCRE1,as a prominent component of the nodulation pathway.GmCRE1 knockout in soybean resulted in a striking nodule phenotype with decreased nitrogen fixation zone and depletion of leghemoglobins,accompanied by downregulation of nodule-specific gene expression,as well as almost complete abrogation of biological nitrogen fixation.In summary,this study provides a comprehensive perspective of the cellular landscape during soybean nodulation,shedding light on the underlying metabolic and developmental mechanisms of soybean nodule formation.展开更多
As a new energy storage element,supercapacitors have characteristics such as high power density,fast charge and discharge rates,green environmental protection,and long cycle life.Temperature is an important parameter ...As a new energy storage element,supercapacitors have characteristics such as high power density,fast charge and discharge rates,green environmental protection,and long cycle life.Temperature is an important parameter of supercapacitors which significantly influences the stability of the supercapacitors.In this study,the finite element method is used to realize a coupling between a one-dimensional electrochemical model and a three-dimensional thermal model.Then,based on this model,the concept of limited cycle numbers is defined,and different unit quantities,unit size,and the effect of temperature under different temperature environments such as low temperature,room temperature,and high temperature on stacked-type supercapacitors is studied.Finally,stacked-type supercapacitors are compared with rolled-type supercapacitors considering the same cell size,density,and volume approximations.The simulation results show that the higher the number of packaging units,the lower is the limit cycle number.This phenomenon is more pronounced under high current than under low current conditions.Increasing the package size of the porous electrode or separator decreases the limiting cycles.Under the same unit volume scenario,improving the separator size proportion can accurately control the temperature rise at small current values.Under the same material,volume,and density approximations,the temperature rises slowly for stacked-type supercapacitors as compared to rolled-type supercapacitors.This phenomenon is more pronounced with an increase in current.展开更多
A flat annular crack in a piezoelectric layer subjected to electroelastic loadings is investigated under electrically impermeable boundary condition on the crack surface. Using Hankel transform technique, the mixed bo...A flat annular crack in a piezoelectric layer subjected to electroelastic loadings is investigated under electrically impermeable boundary condition on the crack surface. Using Hankel transform technique, the mixed boundary value problem is reduced to a system of singular integral equations. With the aid of Gauss-Chebyshev integration technique, the integral equations are further reduced to a system of algebraic equations. The field intensity factor and energy release rate are determined. NumericM results reveal the effects of electric loadings and crack configuration on crack propagation and growth. The results seem useful for design of the piezoelectric structures and devices of high performance.展开更多
Facial and vocal expressions are essential modalities mediating the perception of emotion and social communication. Nonetheless, currently little is known about how emotion perception and its neural substrates differ ...Facial and vocal expressions are essential modalities mediating the perception of emotion and social communication. Nonetheless, currently little is known about how emotion perception and its neural substrates differ across facial expression and vocal prosody. To clarify this issue, functional MRI scans were acquired in Study 1, in which participants were asked to discriminate the valence of emotional expression （angry, happy or neutral） from facial, vocal, or bimodal stimuli. In Study 2, we used an affective priming task （unimodal materials as primers and bimodal materials as target） and participants were asked to rate the intensity, valence, and arousal of the targets. Study 1 showed higher accuracy and shorter response latencies in the facial than in the vocal modality for a happy expression. Whole-brain analysis showed enhanced activation during facial compared to vocal emotions in the inferior temporal-occipital regions. Region of interest analysis showed a higher percentage signal change for facial than for vocal anger in the superior temporal sulcus. Study 2 showed that facial relative to vocal priming of anger had a greater influence on perceived emotion for bimodal targets, irrespective of the target valence. These findings suggest that facial expression is associated with enhanced emotion perception compared to equivalent vocal prosodies.展开更多
Visual recognition of cardiac images is important for cardiac pathology diagnosis and treatment.Due to the limited availability of annotated datasets,traditional methods usually extract features directly from twodimen...Visual recognition of cardiac images is important for cardiac pathology diagnosis and treatment.Due to the limited availability of annotated datasets,traditional methods usually extract features directly from twodimensional slices of three-dimensional(3D)heart images,followed by pathological classification.This process may not ensure the overall anatomical consistency in 3D heart.A new method for classification of cardiac pathology is therefore proposed based on 3D parametric model reconstruction.First,3D heart models are reconstructed based on multiple 3D volumes of cardiac imaging data at the end-systole(ES)and end-diastole(ED)phases.Next,based on these reconstructed 3D hearts,3D parametric models are constructed through the statistical shape model(SSM),and then the heart data are augmented via the variation in shape parameters of one 3D parametric model with visual knowledge constraints.Finally,shape and motion features of 3D heart models across two phases are extracted to classify cardiac pathology.Comprehensive experiments on the automated cardiac diagnosis challenge(ACDC)dataset of the Statistical Atlases and Computational Modelling of the Heart(STACOM)workshop confirm the superior performance and efficiency of this proposed approach.展开更多
基金This work is part of the program of“The research on the optimization and supply-side reliability of oil product logistics system(No.51874325)”,which is funded by the National Natural Science Foundation of China.
文摘The solid particle impurities generated by pipe wall corrosion might deposit at the elbow of hilly pipelines during the production shutdown of oil pipelines.These solid particle impurities will seriously affect the safety of the pipeline operation and the quality of the petroleum products.Thus,it is necessary to study the methods of removing these trapped particles from pipelines.At present,the most common way to remove these solid particle impurities is pigging oil pipelines periodically by utilizing the mechanical pigging method,while the frequent pigging operation will increase the cost and risk of pipeline operation.It is very convenient and economical to remove the accumulated particles out from the pipeline by oil stream,which can be named Hydraulic Pigging Method(HPM).However,the behavior mechanism of particle in flowing oil is still unclear.This motivates the present research on the particles flushed out by the flowing oil.A numerical model governing the trapped particles displacement from the elbow of an inclined oil pipeline is established in the Euler-Lagrangian framework.The simulation is achieved via CFD coupling with DEM.The CFD method is employed to solving the continuous phase flow,while the discrete particle phase is tracked by the DEM.The numerical model is first validated by comparison with results taken from the published literature.From the simulation results,it is observed that the oil stream,carrier phase,can only flush out the solid particles in a certain diameter range under the given operation conditions,and the particles whose diameter beyond that diameter range will cannot be removed out from the pipeline.The influence of the pipe inclined angle,the oil bulk velocity and the particle diameter on the particle migration characteristics is examined in detail.Furthermore,in order to enhance the efficiency of HPM,an Enhanced Hydraulic Pigging Method based on Multi-Physical Field Collaboration(EHPM-MPFC)is also proposed in the present work.The EHPM-MPFC is validated for having high pigging efficiency via the comparison of the migration characteristics of particles during the EHPM-MPFC and HPM process.The present results can provide the guidance to the HPM operation of products pipelines.
基金Project supported by the National Natural Science Foundation of China(Nos.11862021 and 12072166)the Program for Science and Technology of Inner Mongolia Autonomous Region of China(No.2021GG0254)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2020MS01006)
文摘Based on the modified couple-stress theory,the three-dimensional(3D)bending deformation and vibration responses of simply-supported and multilayered twodimensional(2D)decagonal quasicrystal(QC)nanoplates are investigated.The surface loading is assumed to be applied on the top surface in the bending analysis,the tractionfree boundary conditions on both the top and bottom surfaces of the nanoplates are used in the free vibration analysis,and a harmonic concentrated point loading is applied on the top surfaces of the nanoplates in the harmonic response analysis.The general solutions of the extended displacement and traction vectors for the homogeneous QC nanoplates are derived by solving the eigenvalue problem reduced from the final governing equations of motion with the modified couple-stress effect.By utilizing the propagator matrix method,the analytical solutions of the displacements of bending deformation for the phonon and phason fields,the natural frequency of free vibration,and the displacements of the harmonic responses of the phonon and phason fields are obtained.Numerical examples are illustrated to show the effects of the quasiperiodic direction,the material length scale parameter,and the the stacking sequence of the nanoplates on the bending deformation and vibration responses of two sandwich nanoplates made of QC and crystal materials.
基金financially supported by the National Natural Science Foundation of China(No.51771044)the Natural Science Foundation of Hebei Province(No.E2019501061)+2 种基金the Performance subsidy fund for Key Laboratory of Dielectric and Electrolyte Functional Material Hebei(No.22567627H)the Fundamental Research Funds for the Central Universities(No.N2223025)the Programme of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project of China 2.0,No.BP0719037)。
文摘The phase stability,magnetic properties,martensitic transformation,and electronic properties of the Ni_(2−x)Mn_(1+x+y)Sn_(1−y) system with excess Mn have been systematically investigated by the first-principles calculations.Results indicate that the excess Mn atoms will directly occupy the sublattices of Ni(MnNi)or Sn(MnSn).The formation energy(Ef)of the austenite has a relationship with the Mn content:Ef=135.27(1+x+y)−293.01,that is,the phase stability of the austenite decreases gradually with the increase in Mn content.According to the results of the formation energy of austenite,there is an antiparallel arrangement of the magnetic moment between the excess and normal Mn atoms in the Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x=0 or y=0)system,while the magnetic moment direction of the normal Mn atoms arranges antiparallel to that of MnNi atoms and parallel to that of MnSn atoms in the Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x,y≠0)system.The martensitic transformation occurs in some Ni_(2−x)Mn_(1+x+y)Sn_(1−y)(x,y≠0)alloys with large magnetic moments of ferrimagnetic austenite.Besides,the valence electrons tend to distribute around the Ni or MnNi atoms and mainly bond with the normal Mn atoms.The results of this work can lay a theoretical foundation for further development of the Ni_(2−x)Mn_(1+x+y)Sn_(1−y) system as the potential ferromagnetic shape memory alloys.
基金financially supported by the National Natural Science Foundation of China(Grant No.51771044)the Natural Science Foundation of Hebei Province(No.E2019501061)+2 种基金the Fundamental Research Funds for the Central Universities(No.N2023027)the Programme of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project of China 2.0,No.BP0719037)the LiaoNing Revitalization Talents Program(Grant No.XLYC1802023)。
文摘The all-d-metal Ni-Mn-Ti Heusler alloy has giant elastocaloric eff ect and excellent mechanical properties,which is diff erent from the conventional Ni-Mn-based Heusler alloys.In this work,the preferred site occupation,phase stability,martensitic transformation,magnetic properties,and electronic structure of the B-doped Ni_(2)Mn_(1.5)Ti_(0.5)alloys are systematically investigated by the fi rst-principles calculations.The results show that B atoms preferentially occupy the octahedral interstitial.The doped B atoms tend to exist in the(Ni_(2)Mn_(1.5)Ti_(0.5))_(1-x)B_(x)(x=0.03,0.06,0.09)alloy in the form of aggregation distribution,and the martensitic transformation temperature decreases with the increase in the B content.For octahedral interstitial doping,the toughness and plasticity of the(Ni_(2)Mn_(1.5)Ti_(0.5))_(1-x)B_(x) alloys decrease,but the strength and rigidity are greatly enhanced.This is because a small part of the d-d hybridization in ternary Ni-Mn-Ti alloy is replaced by the p-d hybridization in Ni-Mn-Ti-B alloy.
基金supported by the CAS Project for Young Scientists in Basic Research(YSBR-011)National Key Research and Development Program of China(2021YFF1000103)。
文摘Although root nodules are essential for biological nitrogen fixation in legumes,the cell types and molecular regulatory mechanisms contributing to nodule development and nitrogen fixation in determinate nodule legumes,such as soybean(Glycine max),remain incompletely understood.Here,we generated a single-nucleus resolution transcriptomic atlas of soybean roots and nodules at 14 days post inoculation(dpi)and annotated 17 major cell types,including six that are specific to nodules.We identified the specific cell types responsible for each step in the ureides synthesis pathway,which enables spatial compartmentalization of biochemical reactions during soybean nitrogen fixation.By utilizing RNA velocity analysis,we reconstructed the differentiation dynamics of soybean nodules,which differs from those of indeterminate nodules in Medicago truncatula.Moreover,we identified several putative regulators of soybean nodulation and two of these genes,GmbHLH93 and GmSCL1,were as-yet uncharacterized in soybean.Overexpression of each gene in soybean hairy root systems validated their respective roles in nodulation.Notably,enrichment for cytokinin-related genes in soybean nodules led to identification of the cytokinin receptor,GmCRE1,as a prominent component of the nodulation pathway.GmCRE1 knockout in soybean resulted in a striking nodule phenotype with decreased nitrogen fixation zone and depletion of leghemoglobins,accompanied by downregulation of nodule-specific gene expression,as well as almost complete abrogation of biological nitrogen fixation.In summary,this study provides a comprehensive perspective of the cellular landscape during soybean nodulation,shedding light on the underlying metabolic and developmental mechanisms of soybean nodule formation.
文摘As a new energy storage element,supercapacitors have characteristics such as high power density,fast charge and discharge rates,green environmental protection,and long cycle life.Temperature is an important parameter of supercapacitors which significantly influences the stability of the supercapacitors.In this study,the finite element method is used to realize a coupling between a one-dimensional electrochemical model and a three-dimensional thermal model.Then,based on this model,the concept of limited cycle numbers is defined,and different unit quantities,unit size,and the effect of temperature under different temperature environments such as low temperature,room temperature,and high temperature on stacked-type supercapacitors is studied.Finally,stacked-type supercapacitors are compared with rolled-type supercapacitors considering the same cell size,density,and volume approximations.The simulation results show that the higher the number of packaging units,the lower is the limit cycle number.This phenomenon is more pronounced under high current than under low current conditions.Increasing the package size of the porous electrode or separator decreases the limiting cycles.Under the same unit volume scenario,improving the separator size proportion can accurately control the temperature rise at small current values.Under the same material,volume,and density approximations,the temperature rises slowly for stacked-type supercapacitors as compared to rolled-type supercapacitors.This phenomenon is more pronounced with an increase in current.
基金Project supported by the National Natural Science Foundation of China(Nos.11072160 and 11272223)the Natural Science Foundation of Hebei Province,China(E2013402077)
文摘A flat annular crack in a piezoelectric layer subjected to electroelastic loadings is investigated under electrically impermeable boundary condition on the crack surface. Using Hankel transform technique, the mixed boundary value problem is reduced to a system of singular integral equations. With the aid of Gauss-Chebyshev integration technique, the integral equations are further reduced to a system of algebraic equations. The field intensity factor and energy release rate are determined. NumericM results reveal the effects of electric loadings and crack configuration on crack propagation and growth. The results seem useful for design of the piezoelectric structures and devices of high performance.
基金supported by the National Natural Science Foundation of China(31371042 and 31671164)
文摘Facial and vocal expressions are essential modalities mediating the perception of emotion and social communication. Nonetheless, currently little is known about how emotion perception and its neural substrates differ across facial expression and vocal prosody. To clarify this issue, functional MRI scans were acquired in Study 1, in which participants were asked to discriminate the valence of emotional expression （angry, happy or neutral） from facial, vocal, or bimodal stimuli. In Study 2, we used an affective priming task （unimodal materials as primers and bimodal materials as target） and participants were asked to rate the intensity, valence, and arousal of the targets. Study 1 showed higher accuracy and shorter response latencies in the facial than in the vocal modality for a happy expression. Whole-brain analysis showed enhanced activation during facial compared to vocal emotions in the inferior temporal-occipital regions. Region of interest analysis showed a higher percentage signal change for facial than for vocal anger in the superior temporal sulcus. Study 2 showed that facial relative to vocal priming of anger had a greater influence on perceived emotion for bimodal targets, irrespective of the target valence. These findings suggest that facial expression is associated with enhanced emotion perception compared to equivalent vocal prosodies.
基金Project supported by the National Natural Science Foundation of China(Nos.72091511,62172047,and 61802020)。
文摘Visual recognition of cardiac images is important for cardiac pathology diagnosis and treatment.Due to the limited availability of annotated datasets,traditional methods usually extract features directly from twodimensional slices of three-dimensional(3D)heart images,followed by pathological classification.This process may not ensure the overall anatomical consistency in 3D heart.A new method for classification of cardiac pathology is therefore proposed based on 3D parametric model reconstruction.First,3D heart models are reconstructed based on multiple 3D volumes of cardiac imaging data at the end-systole(ES)and end-diastole(ED)phases.Next,based on these reconstructed 3D hearts,3D parametric models are constructed through the statistical shape model(SSM),and then the heart data are augmented via the variation in shape parameters of one 3D parametric model with visual knowledge constraints.Finally,shape and motion features of 3D heart models across two phases are extracted to classify cardiac pathology.Comprehensive experiments on the automated cardiac diagnosis challenge(ACDC)dataset of the Statistical Atlases and Computational Modelling of the Heart(STACOM)workshop confirm the superior performance and efficiency of this proposed approach.
