In this paper, we obtain a class of common fixed point theorems for generalized Lipschitz mappings in cone metric spaces with Banach algebras without the assumption of normality of cones. The results greatly generaliz...In this paper, we obtain a class of common fixed point theorems for generalized Lipschitz mappings in cone metric spaces with Banach algebras without the assumption of normality of cones. The results greatly generalize some results in the literature. Moreover,we give an example to support the main assertions.展开更多
Let(X,d)be a cone metric space and T:X!X be a mapping.In this paper,we shall introduce the concept of strong T-stability of fixed point iteration procedures with respect to T in cone metric spaces.Also,we will investi...Let(X,d)be a cone metric space and T:X!X be a mapping.In this paper,we shall introduce the concept of strong T-stability of fixed point iteration procedures with respect to T in cone metric spaces.Also,we will investigate some meaningful results on strong T-stability of Picard iterations in cone metric spaces without the assumption of normality.Our main results improve and generalize some related results in the literature.展开更多
Crossflow instability will be present when the vehicle has an angle of attack in hypersonic flow,and it might play a dominant role in hypersonic boundary layer transition.By far the mechanism of crossflow instability-...Crossflow instability will be present when the vehicle has an angle of attack in hypersonic flow,and it might play a dominant role in hypersonic boundary layer transition.By far the mechanism of crossflow instability-induced hypersonic boundary layer transition is still out of understanding,although the large effort has been devoted.Upon this work,the overall roughness effect on instabilities in hypersonic flow was researched experimentally.Surface flush-mounted pressure sensors and infrared camera were employed to investigate the instability waves when different rough surfaces were deployed.The results reveal that the moderate surface roughness level on cone model can suppress the growth of crossflow instabilities at certain azimuthal angles in hypersonic flow.展开更多
In the reliability designing procedure of the vehicle components, when the distribution styles of the random variables are unknown or non-normal distribution, the result evaluated contains great error or even is wrong...In the reliability designing procedure of the vehicle components, when the distribution styles of the random variables are unknown or non-normal distribution, the result evaluated contains great error or even is wrong if the reliability value R is larger than 1 by using the existent method, in which case the formula is necessary to be revised. This is obviously inconvenient for programming. Combining reliability-based optimization theory, robust designing method and reliability based sensitivity analysis, a new method for reliability robust designing is proposed. Therefore the influence level of the designing parameters’ changing to the reliability of vehicle components can be obtained. The reliability sensitivity with respect to design parameters is viewed as a sub-objective function in the multi-objective optimization problem satisfying reliability constraints. Given the first four moments of basic random variables, a fourth-moment technique and the proposed optimization procedure can obtain reliability-based robust design of automobile components with non-normal distribution parameters accurately and quickly. By using the proposed method, the distribution style of the random parameters is relaxed. Therefore it is much closer to the actual reliability problems. The numerical examples indicate the following: (1) The reliability value obtained by the robust method proposed increases (】0.04%) comparing to the value obtained by the ordinary optimization algorithm; (2) The absolute value of reliability-based sensitivity decreases (】0.01%), and the robustness of the products’ quality is improved accordingly. Utilizing the reliability-based optimization and robust design method in the reliability designing procedure reduces the manufacture cost and provides the theoretical basis for the reliability and robust design of the vehicle components.展开更多
Traditional methods for early warning of dam displacements usually assume that residual displacements follow a normal distribution.This assumption deviates from the reality,thereby affecting the reliability of early w...Traditional methods for early warning of dam displacements usually assume that residual displacements follow a normal distribution.This assumption deviates from the reality,thereby affecting the reliability of early warning results and leading to misjudgments of dam displacement behavior.To solve this problem,this study proposed an early warning method using a non-normal distribution function.A new early warning index was developed using cumulative distribution function(CDF)values.The method of kernel density estimation was used to calculate the CDF values of residual displacements at a single point.The copula function was used to compute the CDF values of residual displacements at multiple points.Numerical results showed that,with residual displacements in a non-normal distribution,the early warning method proposed in this study accurately reflected the dam displacement behavior and effectively reduced the frequency of false alarms.This method is expected to aid in the safe operation of dams.展开更多
Various kinds of Riemann boundary value problems (BVPs) for analytic functions on closed curves or on open arc, doubly periodic Riemann BVPs, doubly quasi-periodic Riemann BVPs, and BVPs for polyanalytic functions hav...Various kinds of Riemann boundary value problems (BVPs) for analytic functions on closed curves or on open arc, doubly periodic Riemann BVPs, doubly quasi-periodic Riemann BVPs, and BVPs for polyanalytic functions have been widely investigated in [1-8]. The main ap- proach is to use the decomposition of polyanalytic functions and their generalization to transform the boundary value problems to their corresponding boundary value problems for analytic functions. Recently, inverse Riemann BVPs for generalized analytic functions or bianalytic functions have been investigated in [9-12]. In this paper, we consider a kind of Riemann BVP of non-normal type on the infinite straight line and discuss the solvable conditions and the general solution for it.展开更多
We will discuss the non-normal Hasemann boundary value problem: we may find these results are coincided with those of normal Hasemann boundary value problem and non-normal Riemann boundary value problem.
In this paper, we present and study a kind of Riemann boundary value problem of non-normal type for analytic functions on two parallel curves. Making use of the method of complex functions, we give the method for solv...In this paper, we present and study a kind of Riemann boundary value problem of non-normal type for analytic functions on two parallel curves. Making use of the method of complex functions, we give the method for solving this kind of doubly periodic Riemann boundary value problem of non-normal type and obtain the explicit expressions of solutions and the solvable conditions for it.展开更多
The optimization of the waverider is constrained by the reversely designed leading edge and the constant shock angle distribution. This paper proposes a design method called the variable Leading-Edge Cone (vLEC) metho...The optimization of the waverider is constrained by the reversely designed leading edge and the constant shock angle distribution. This paper proposes a design method called the variable Leading-Edge Cone (vLEC) method to address these limitations. In the vLEC method, the waverider is directly designed from the preassigned leading edge and the variable shock angle distribution based on the Leading-Edge Cone (LEC) concept. Since the vLEC method is an approximate method, two test waveriders are designed and evaluated using numerical simulations to validate the shock design accuracy and the effectiveness of the vLEC method. The results show that the shocks of the test waveriders coincide well with the preassigned positions. Furthermore, four specifically designed application cases are conducted to analyze the performance benefits of the vLEC waveriders. The results of these cases indicate that, due to their variable shock angle distributions, the vLEC waveriders exhibit higher lift-to-drag ratios and better longitudinal static stability than conventional waveriders. Additionally, the vLEC waveriders demonstrate superior volumetric capacities near the symmetry plane, albeit with a minor decrease in volumetric efficiency.展开更多
Harrat Lunayyir,a volcanic field in western Saudi Arabia,exhibits diverse geomorphological and topographical features shaped by volcanic,tectonic,and climatic processes.This study integrates field observations,remote ...Harrat Lunayyir,a volcanic field in western Saudi Arabia,exhibits diverse geomorphological and topographical features shaped by volcanic,tectonic,and climatic processes.This study integrates field observations,remote sensing,and GIS analysis to investigate the spatial distribution and relationships between volcanic landforms,lava flows,and topographical variation result obtained is a morphological classification of the cinder cones of Harrat Lunayyir,which can be sub-divided into four types:tephra rings,horseshoe-shaped volcanoes,multiple volcanoes and volcanoes without craters.All of these are monogenetic volcanoes,unlike central volcanoes(stratovolcanoes)which live for tens or hundreds of thousands of years and erupt numerous times.In Harrat Lunayyir,there is a clear dominance of arched horseshoe-shaped volcanoes(58)over ring-shaped cinder cones(10),A1_symmetric cones(circular,uniform cinder cones with a single crater)(32),A2_asymmetric cones(elongated,irregular cones and may feature one or more craters)(8),volcanoes without craters(55)and multiple volcanoes(20).The classification presented in this paper makes it possible to include all morphological types of volcanoes found in the region.This fact also renders the present classification a useful tool to apply in other,both insular and continental volcanic areas to eventually analyze and systematize the study of eruptive edifices with similar traits.Hence,this research will explore the standard physical volcanology literature so as to follow accepted definitions.展开更多
We explore some necessary and sufficient conditions for the boundedness of the Forelli-Rudin type operator T on the weighted Lebesgue space associated with tubular domains over the forward light cone.Our approach invo...We explore some necessary and sufficient conditions for the boundedness of the Forelli-Rudin type operator T on the weighted Lebesgue space associated with tubular domains over the forward light cone.Our approach involves conducting precise computations for a series of complex integrals to identify appropriate test functions,and through a detailed analysis of these test functions,we derive the boundedness properties of the operator T.This work is significant in the study of the Bergman projection operators.展开更多
Currently,the cranes used at sea do not have enough flexibility,efficiency,and safety.Thus,this study proposed a floating multirobot coordinated towing system to meet the demands for offshore towing.Because of the fle...Currently,the cranes used at sea do not have enough flexibility,efficiency,and safety.Thus,this study proposed a floating multirobot coordinated towing system to meet the demands for offshore towing.Because of the flexibility of rope-driven robots,the one-way pulling characteristics of the rope,and the floating characteristics of the base,towing robots are easily overturned.First,the spatial configuration of the towing system was established according to the towing task,and the kinematic model of the towing system was established using the coordinate transformation.Then,the dynamic model of the towing system was established according to the rigid-body dynamics and hydrodynamic theory.Finally,the stability of the towing system was analyzed using the stability cone method.The simulation experiments provide a reference for the practical application of the floating multirobot coordinated towing system,which can improve the stability of towing systems by changing the configuration of the towing robot.展开更多
Background:Although Cone reconstruction has been shown to improve biventricular functionover time,postoperative right ventricular dysfunction(RVD)is frequently observed,signiffcantly affectingreoperation and long-term...Background:Although Cone reconstruction has been shown to improve biventricular functionover time,postoperative right ventricular dysfunction(RVD)is frequently observed,signiffcantly affectingreoperation and long-term prognosis.This study aims to identify the predictors for postoperative RVD.Methods:This retrospective cohort study included 51 patients with Ebstein’s anomaly who underwentthe Cone reconstruction.RVD was deffned as right ventricular fractional area change(RV-FAC)lessthan 35%and tricuspid annular plane systolic excursion(TAPSE)less than 17 mm through pre-dischargeechocardiography.Univariate and multivariate analyses were used to analyze the pre-operative predictors.Results:The median age at surgery was 37.7(±15.3)years,RVD was documented in 25 patients(49%)of the51 patients.Patients with RVD had signiffcantly higher right ventricular end-systolic volume index(RVESVi)(p=0.001),right ventricular end-diastolic volume index(RVEDVi)(p=0.03),and septal leaffet displacement(p=0.003).Multivariate analysis conffrmed that septal leaffet displacement was independently associatedwith postoperative RVD(p=0.02).Additionally,RVD was not related to the cardiopulmonary bypass time,ICU stay and total hospital time.Conclusions:This study suggests that preoperative right ventricularejection fraction(RVEF)reduction,severe septal leaffet displacement and signiffcant right ventriculardilatation are key predictors of early postoperative RVD.RVD may exacerbate tricuspid regurgitation,andthis ffnding indicates that predicting RVD may aid in identifying high-risk patients prone to recurrence oftricuspid regurgitation after Cone reconstruction.展开更多
For cone beam computed tomography(CBCT),there has long been a desire to modulate the intensity and distribution of the X-rays to accommodate the patient’s anatomy as the gantry rotates from one projection to another....For cone beam computed tomography(CBCT),there has long been a desire to modulate the intensity and distribution of the X-rays to accommodate the patient’s anatomy as the gantry rotates from one projection to another.This would reduce both image artifacts and radiation dose.However,the current beam modulation setups,such as dynamic bowtie filters,may be too complex for practical use in clinical applications.This study aimed to investigate a simplified dynamic beam filtration strategy for CBCT imaging to reduce image artifacts and radiation dose.In this study,the beam filtration was designed to vary dynamically as the CBCT gantry rotates around the object.Specifically,two distinct components were integrated:the sheet filter part and the bowtie filter part.The dynamic beam filtration setup has two working schemes,one is a combination of dynamic sheet filter and dynamic bowtie filter,denoted as dynamic filterdynamic bowtie(DFDB);the other is a combination of dynamic sheet filter and static bowtie filter,denoted as dynamic filter-static bowtie(DFSB).Numerical imaging experiments were performed for three human body parts:the shoulder,chest,and knee.In addition,the Monte Carlo simulation platform MC-GPU was used to generate the dose distribution maps.Results showed that the proposed DFDB and DFSB beam filtration schemes can significantly reduce the image artifacts and thus improve the CBCT image quality.Depending on the scanned object,the total radiation dose could be reduced by 30%.The proposed simple dynamic beam filtration strategy,especially the DFSB approach,could be beneficial in the future to improve the CBCT image quality with reduced image artifacts and radiation dose.展开更多
The hydrogen-enriched direct reduction shaft furnace addresses the high CO_(2) emissions associated with the blast furnace process.A discrete element method(DEM)model was introduced to explore how the structure of the...The hydrogen-enriched direct reduction shaft furnace addresses the high CO_(2) emissions associated with the blast furnace process.A discrete element method(DEM)model was introduced to explore how the structure of the diversion cone affects particle descent behavior in a hydrogen-enriched shaft furnace.The results indicated that in the absence of a diversion cone,the descending velocity near the furnace wall zone is significantly lower than that at its center,resulting in a‘V’-shaped burden flow pattern.The discharge velocity has a minor impact on the flow pattern in the shaft furnace.Upon installation of a diversion cone,burden descending velocity becomes more uniform,leading to a‘-’-shaped burden flow pattern.As the bottom of the diversion cone ascends(i.e.,the lower end of the diversion cone is progressively closer to the top),there is an increase in the volume fraction of the dead zone within the shaft furnace.This is particularly evident in the formation of a triangular dead zone at the base of the diversion cone.It is suggested that the lower cone of the bi-conical diversion cone should maintain a sufficient height.展开更多
Direct laser acceleration is one of the mechanisms for producing electron bunches carrying up to μC charge,which has attracted much attention in recent decades.Currently,one major challenge for its applications to hi...Direct laser acceleration is one of the mechanisms for producing electron bunches carrying up to μC charge,which has attracted much attention in recent decades.Currently,one major challenge for its applications to high-flux x-ray beams and Comptonγ-ray sources is the relatively large divergence angle(hundreds of mrad).In this work,a scheme to guide and focus the incident laser and the accelerated electrons is proposed and tested through two-dimensional(2D)particle-in-cell(PIC)simulations.The scheme is based on a hollow cone target(made of aluminum or gold)filled with near-critical-density(NCD)plasmas(pre-ionized polymer foams).Instead of separating the acceleration and focusing processes,it is convenient to simultaneously realize both requirements in such an NCD plasma-filled cone target.PIC simulations reveal that the laser,electrons,and emitted photons can be well-guided along the cone axis in the NCD plasma-filled cone target,preserving the characteristic of high beam charge.Detailed PIC simulations are also performed to show the dependence of the electron energy and charge on the plasma density for a given laser.展开更多
Dielectric elastomer(DE)is an electroactive polymer with the characteristics of high energy output,great flexibility,light-weight,mechanical compliance,and low cost,which are particularly suitable for DE energy genera...Dielectric elastomer(DE)is an electroactive polymer with the characteristics of high energy output,great flexibility,light-weight,mechanical compliance,and low cost,which are particularly suitable for DE energy generators.Energy harvesting efficiency is a key index to evaluate the performance of the energy generator,which depends on the structural configuration and the mechanical and dielectric properties of the DE material.This paper proposes a fractional viscoelastic polarization(FVP)model by combining the fractional viscoelasticity model and the polarization-based lumped parameter model.A dynamical model of a cone dielectric energy generator(CDEG)considering stretch-dependent electrostriction and nonlinear viscoelasticity is established.Additionally,a deep neural network(DNN)model is developed to explore the relationships between various parameters and the output energy of CDEGs to efficiently and accurately predict the energy output of CDEGs.Based on the DNN model,optimal parameter designs for CDEGs are obtained by using non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ).The experiments verified that the FVP model predicts accurately the output energy of CDEG and the established optimal design framework can accurately provide the optimal design parameters of CDEG,which offers deep insights for the design and fabrication of a high-efficiency dielectric energy generator.展开更多
Cone penetration testing(CPT)and its variant with pore pressure measurements(CPTu)are versatile tools that have been traditionally used for in situ geotechnical site investigations.These investigations are among the m...Cone penetration testing(CPT)and its variant with pore pressure measurements(CPTu)are versatile tools that have been traditionally used for in situ geotechnical site investigations.These investigations are among the most challenging yet indispensable tasks,providing a crucial reference for infrastructure planning,design and construction.However,data obtained through the CPT/CPTu testing often exhibit significant variability,even at closely spaced test points.This variability is primarily attributed to the complex mineral compositions and sedimentary process of the Quaternary sediments.Problems induced by the scattering data include the difficulties in estimating the shear strength of the sediments and determining the appropriate bearing stratum for pile foundations.In this paper,the conventional interpretation methods of the CPT/CPTu data are enhanced with sedimentary facies knowledge.The geotechnical investigation mainly involves 42 CPTu tests(39 essential data sets available)and 4 boring samples.Sediment types are interpreted from the CPTu data and calibrated by the nearby boring samples.Sedimentary facies are derived from the interpreted sequence stratigraphy,for which the interpretation skills are summarized in the form of characteristic curves of the CPTu data.Scattering distribution of the sediment types and their mechanical parameters are well explained by the sedimentary facies.The sediments are then categorized into a few groups by their sedimentary facies,resulting in reduced uncertainties and scattering in terms of shear strength.Bearing stratum of pile foundations is also suggested based on the sedimentary regulations.展开更多
Stafne骨腔(Stafne bone cavity,SBC)又称静止性骨腔,是一种出现在下颌骨舌面少见的骨质缺损。SBC通常发生在下颌角附近,极少出现在下颌骨前部。本文报道1例位于下颌骨前磨牙区的SBC病例,通过复习相关文献,加深口腔医生对不典型位置SBC...Stafne骨腔(Stafne bone cavity,SBC)又称静止性骨腔,是一种出现在下颌骨舌面少见的骨质缺损。SBC通常发生在下颌角附近,极少出现在下颌骨前部。本文报道1例位于下颌骨前磨牙区的SBC病例,通过复习相关文献,加深口腔医生对不典型位置SBC的认识,避免误诊。展开更多
基金Supported by the Science and Technology Research Project of the Education Department of Hubei Province（B2015137） Supported by the National Social Science Foundation of China（12BZS050）
文摘In this paper, we obtain a class of common fixed point theorems for generalized Lipschitz mappings in cone metric spaces with Banach algebras without the assumption of normality of cones. The results greatly generalize some results in the literature. Moreover,we give an example to support the main assertions.
基金supported by the Special Basic Cooperative Research Programs of Yunnan Provincial Undergraduate Universities’Association(grant No.202101BA070001-045)the Foundation of Major Basic Research Projects,Hanshan Normal University,China(No.ZD201807).
文摘Let(X,d)be a cone metric space and T:X!X be a mapping.In this paper,we shall introduce the concept of strong T-stability of fixed point iteration procedures with respect to T in cone metric spaces.Also,we will investigate some meaningful results on strong T-stability of Picard iterations in cone metric spaces without the assumption of normality.Our main results improve and generalize some related results in the literature.
基金supported by the National Natural Science Foundation of China(No.11972357)。
文摘Crossflow instability will be present when the vehicle has an angle of attack in hypersonic flow,and it might play a dominant role in hypersonic boundary layer transition.By far the mechanism of crossflow instability-induced hypersonic boundary layer transition is still out of understanding,although the large effort has been devoted.Upon this work,the overall roughness effect on instabilities in hypersonic flow was researched experimentally.Surface flush-mounted pressure sensors and infrared camera were employed to investigate the instability waves when different rough surfaces were deployed.The results reveal that the moderate surface roughness level on cone model can suppress the growth of crossflow instabilities at certain azimuthal angles in hypersonic flow.
基金supported by National Natural Science Foundation of China (Grant Nos. 51135003, U1234208, 51205050)New Teachers' Fund for Doctor Stations of Ministry of Education of China (Grant No.20110042120020)+1 种基金Fundamental Research Funds for the Central Universities, China (Grant No. N110303003)China Postdoctoral Science Foundation (Grant No. 2011M500564)
文摘In the reliability designing procedure of the vehicle components, when the distribution styles of the random variables are unknown or non-normal distribution, the result evaluated contains great error or even is wrong if the reliability value R is larger than 1 by using the existent method, in which case the formula is necessary to be revised. This is obviously inconvenient for programming. Combining reliability-based optimization theory, robust designing method and reliability based sensitivity analysis, a new method for reliability robust designing is proposed. Therefore the influence level of the designing parameters’ changing to the reliability of vehicle components can be obtained. The reliability sensitivity with respect to design parameters is viewed as a sub-objective function in the multi-objective optimization problem satisfying reliability constraints. Given the first four moments of basic random variables, a fourth-moment technique and the proposed optimization procedure can obtain reliability-based robust design of automobile components with non-normal distribution parameters accurately and quickly. By using the proposed method, the distribution style of the random parameters is relaxed. Therefore it is much closer to the actual reliability problems. The numerical examples indicate the following: (1) The reliability value obtained by the robust method proposed increases (】0.04%) comparing to the value obtained by the ordinary optimization algorithm; (2) The absolute value of reliability-based sensitivity decreases (】0.01%), and the robustness of the products’ quality is improved accordingly. Utilizing the reliability-based optimization and robust design method in the reliability designing procedure reduces the manufacture cost and provides the theoretical basis for the reliability and robust design of the vehicle components.
基金supported by the National Natural Science Foundation of China(Grant No.52109156)the Science and Technology Project of the Jiangxi Provincial Education Department(Grant No.GJJ190970).
文摘Traditional methods for early warning of dam displacements usually assume that residual displacements follow a normal distribution.This assumption deviates from the reality,thereby affecting the reliability of early warning results and leading to misjudgments of dam displacement behavior.To solve this problem,this study proposed an early warning method using a non-normal distribution function.A new early warning index was developed using cumulative distribution function(CDF)values.The method of kernel density estimation was used to calculate the CDF values of residual displacements at a single point.The copula function was used to compute the CDF values of residual displacements at multiple points.Numerical results showed that,with residual displacements in a non-normal distribution,the early warning method proposed in this study accurately reflected the dam displacement behavior and effectively reduced the frequency of false alarms.This method is expected to aid in the safe operation of dams.
文摘Various kinds of Riemann boundary value problems (BVPs) for analytic functions on closed curves or on open arc, doubly periodic Riemann BVPs, doubly quasi-periodic Riemann BVPs, and BVPs for polyanalytic functions have been widely investigated in [1-8]. The main ap- proach is to use the decomposition of polyanalytic functions and their generalization to transform the boundary value problems to their corresponding boundary value problems for analytic functions. Recently, inverse Riemann BVPs for generalized analytic functions or bianalytic functions have been investigated in [9-12]. In this paper, we consider a kind of Riemann BVP of non-normal type on the infinite straight line and discuss the solvable conditions and the general solution for it.
基金the National Natural Science Foundation of ChinaRF DP of Higher Education and SF of Wuhan Uni-versity(2 0 1990 3 3 6)
文摘We will discuss the non-normal Hasemann boundary value problem: we may find these results are coincided with those of normal Hasemann boundary value problem and non-normal Riemann boundary value problem.
文摘In this paper, we present and study a kind of Riemann boundary value problem of non-normal type for analytic functions on two parallel curves. Making use of the method of complex functions, we give the method for solving this kind of doubly periodic Riemann boundary value problem of non-normal type and obtain the explicit expressions of solutions and the solvable conditions for it.
基金supported by grants from the National Natural Science Foundation of China(No.U20B2006)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110145)Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.2022QNRC001).
文摘The optimization of the waverider is constrained by the reversely designed leading edge and the constant shock angle distribution. This paper proposes a design method called the variable Leading-Edge Cone (vLEC) method to address these limitations. In the vLEC method, the waverider is directly designed from the preassigned leading edge and the variable shock angle distribution based on the Leading-Edge Cone (LEC) concept. Since the vLEC method is an approximate method, two test waveriders are designed and evaluated using numerical simulations to validate the shock design accuracy and the effectiveness of the vLEC method. The results show that the shocks of the test waveriders coincide well with the preassigned positions. Furthermore, four specifically designed application cases are conducted to analyze the performance benefits of the vLEC waveriders. The results of these cases indicate that, due to their variable shock angle distributions, the vLEC waveriders exhibit higher lift-to-drag ratios and better longitudinal static stability than conventional waveriders. Additionally, the vLEC waveriders demonstrate superior volumetric capacities near the symmetry plane, albeit with a minor decrease in volumetric efficiency.
文摘Harrat Lunayyir,a volcanic field in western Saudi Arabia,exhibits diverse geomorphological and topographical features shaped by volcanic,tectonic,and climatic processes.This study integrates field observations,remote sensing,and GIS analysis to investigate the spatial distribution and relationships between volcanic landforms,lava flows,and topographical variation result obtained is a morphological classification of the cinder cones of Harrat Lunayyir,which can be sub-divided into four types:tephra rings,horseshoe-shaped volcanoes,multiple volcanoes and volcanoes without craters.All of these are monogenetic volcanoes,unlike central volcanoes(stratovolcanoes)which live for tens or hundreds of thousands of years and erupt numerous times.In Harrat Lunayyir,there is a clear dominance of arched horseshoe-shaped volcanoes(58)over ring-shaped cinder cones(10),A1_symmetric cones(circular,uniform cinder cones with a single crater)(32),A2_asymmetric cones(elongated,irregular cones and may feature one or more craters)(8),volcanoes without craters(55)and multiple volcanoes(20).The classification presented in this paper makes it possible to include all morphological types of volcanoes found in the region.This fact also renders the present classification a useful tool to apply in other,both insular and continental volcanic areas to eventually analyze and systematize the study of eruptive edifices with similar traits.Hence,this research will explore the standard physical volcanology literature so as to follow accepted definitions.
基金Liu’s research was supported by the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(31610030)Deng’s research was supported by the NSFC(11971042,12071035)the National Key R&D Program of China(2021YFA1002600).
文摘We explore some necessary and sufficient conditions for the boundedness of the Forelli-Rudin type operator T on the weighted Lebesgue space associated with tubular domains over the forward light cone.Our approach involves conducting precise computations for a series of complex integrals to identify appropriate test functions,and through a detailed analysis of these test functions,we derive the boundedness properties of the operator T.This work is significant in the study of the Bergman projection operators.
基金Supported by the National Natural Science Foundation of China under Grant No.51965032the Natural Science Foundation of Gansu Province of China under Grant No.22JR5RA319+2 种基金the Excellent Doctoral Student Foundation of Gansu Province of China under Grant No.23JRRA842the Sichuan Province Engineering Technology Research Center of General Aircraft Maintenance under Grant No.GAMRC2023YB05the Key Research and Development Project of Lanzhou Jiaotong University under Grant No.LZJTUZDYF2302.
文摘Currently,the cranes used at sea do not have enough flexibility,efficiency,and safety.Thus,this study proposed a floating multirobot coordinated towing system to meet the demands for offshore towing.Because of the flexibility of rope-driven robots,the one-way pulling characteristics of the rope,and the floating characteristics of the base,towing robots are easily overturned.First,the spatial configuration of the towing system was established according to the towing task,and the kinematic model of the towing system was established using the coordinate transformation.Then,the dynamic model of the towing system was established according to the rigid-body dynamics and hydrodynamic theory.Finally,the stability of the towing system was analyzed using the stability cone method.The simulation experiments provide a reference for the practical application of the floating multirobot coordinated towing system,which can improve the stability of towing systems by changing the configuration of the towing robot.
基金funded by E Fund Congenital Heart Disease Medical Talent Cultivation and Education Fund(grant number[2023QT0009])the Science and Technology Planning Project of Guangdong Province(grant number[2023B03J1255]).
文摘Background:Although Cone reconstruction has been shown to improve biventricular functionover time,postoperative right ventricular dysfunction(RVD)is frequently observed,signiffcantly affectingreoperation and long-term prognosis.This study aims to identify the predictors for postoperative RVD.Methods:This retrospective cohort study included 51 patients with Ebstein’s anomaly who underwentthe Cone reconstruction.RVD was deffned as right ventricular fractional area change(RV-FAC)lessthan 35%and tricuspid annular plane systolic excursion(TAPSE)less than 17 mm through pre-dischargeechocardiography.Univariate and multivariate analyses were used to analyze the pre-operative predictors.Results:The median age at surgery was 37.7(±15.3)years,RVD was documented in 25 patients(49%)of the51 patients.Patients with RVD had signiffcantly higher right ventricular end-systolic volume index(RVESVi)(p=0.001),right ventricular end-diastolic volume index(RVEDVi)(p=0.03),and septal leaffet displacement(p=0.003).Multivariate analysis conffrmed that septal leaffet displacement was independently associatedwith postoperative RVD(p=0.02).Additionally,RVD was not related to the cardiopulmonary bypass time,ICU stay and total hospital time.Conclusions:This study suggests that preoperative right ventricularejection fraction(RVEF)reduction,severe septal leaffet displacement and signiffcant right ventriculardilatation are key predictors of early postoperative RVD.RVD may exacerbate tricuspid regurgitation,andthis ffnding indicates that predicting RVD may aid in identifying high-risk patients prone to recurrence oftricuspid regurgitation after Cone reconstruction.
文摘For cone beam computed tomography(CBCT),there has long been a desire to modulate the intensity and distribution of the X-rays to accommodate the patient’s anatomy as the gantry rotates from one projection to another.This would reduce both image artifacts and radiation dose.However,the current beam modulation setups,such as dynamic bowtie filters,may be too complex for practical use in clinical applications.This study aimed to investigate a simplified dynamic beam filtration strategy for CBCT imaging to reduce image artifacts and radiation dose.In this study,the beam filtration was designed to vary dynamically as the CBCT gantry rotates around the object.Specifically,two distinct components were integrated:the sheet filter part and the bowtie filter part.The dynamic beam filtration setup has two working schemes,one is a combination of dynamic sheet filter and dynamic bowtie filter,denoted as dynamic filterdynamic bowtie(DFDB);the other is a combination of dynamic sheet filter and static bowtie filter,denoted as dynamic filter-static bowtie(DFSB).Numerical imaging experiments were performed for three human body parts:the shoulder,chest,and knee.In addition,the Monte Carlo simulation platform MC-GPU was used to generate the dose distribution maps.Results showed that the proposed DFDB and DFSB beam filtration schemes can significantly reduce the image artifacts and thus improve the CBCT image quality.Depending on the scanned object,the total radiation dose could be reduced by 30%.The proposed simple dynamic beam filtration strategy,especially the DFSB approach,could be beneficial in the future to improve the CBCT image quality with reduced image artifacts and radiation dose.
基金the National Key R&D Program of China(Nos.2021YFC2902400 and 2021YFC2902401)the project of State Key Laboratory of Intelligent Optimized Manufacturing in Mining&Metallurgy Process(No.BGRIMM-KZSKL-2023-14).
文摘The hydrogen-enriched direct reduction shaft furnace addresses the high CO_(2) emissions associated with the blast furnace process.A discrete element method(DEM)model was introduced to explore how the structure of the diversion cone affects particle descent behavior in a hydrogen-enriched shaft furnace.The results indicated that in the absence of a diversion cone,the descending velocity near the furnace wall zone is significantly lower than that at its center,resulting in a‘V’-shaped burden flow pattern.The discharge velocity has a minor impact on the flow pattern in the shaft furnace.Upon installation of a diversion cone,burden descending velocity becomes more uniform,leading to a‘-’-shaped burden flow pattern.As the bottom of the diversion cone ascends(i.e.,the lower end of the diversion cone is progressively closer to the top),there is an increase in the volume fraction of the dead zone within the shaft furnace.This is particularly evident in the formation of a triangular dead zone at the base of the diversion cone.It is suggested that the lower cone of the bi-conical diversion cone should maintain a sufficient height.
基金supported by the Fund of the National Key Laboratory of Plasma Physics(Grant No.6142A04230204)the National Natural Science Foundation of China(Grant No.12075046)。
文摘Direct laser acceleration is one of the mechanisms for producing electron bunches carrying up to μC charge,which has attracted much attention in recent decades.Currently,one major challenge for its applications to high-flux x-ray beams and Comptonγ-ray sources is the relatively large divergence angle(hundreds of mrad).In this work,a scheme to guide and focus the incident laser and the accelerated electrons is proposed and tested through two-dimensional(2D)particle-in-cell(PIC)simulations.The scheme is based on a hollow cone target(made of aluminum or gold)filled with near-critical-density(NCD)plasmas(pre-ionized polymer foams).Instead of separating the acceleration and focusing processes,it is convenient to simultaneously realize both requirements in such an NCD plasma-filled cone target.PIC simulations reveal that the laser,electrons,and emitted photons can be well-guided along the cone axis in the NCD plasma-filled cone target,preserving the characteristic of high beam charge.Detailed PIC simulations are also performed to show the dependence of the electron energy and charge on the plasma density for a given laser.
基金supported by the National Natural Science Foundation of China(Grant Nos.12372027 and 12402109)the Natural Science Foundation of Shandong Province(Grant No.ZR2022MA086)the Basic Scientific Research Expenses of Central Government Universities(Grant No.23CX03010A).
文摘Dielectric elastomer(DE)is an electroactive polymer with the characteristics of high energy output,great flexibility,light-weight,mechanical compliance,and low cost,which are particularly suitable for DE energy generators.Energy harvesting efficiency is a key index to evaluate the performance of the energy generator,which depends on the structural configuration and the mechanical and dielectric properties of the DE material.This paper proposes a fractional viscoelastic polarization(FVP)model by combining the fractional viscoelasticity model and the polarization-based lumped parameter model.A dynamical model of a cone dielectric energy generator(CDEG)considering stretch-dependent electrostriction and nonlinear viscoelasticity is established.Additionally,a deep neural network(DNN)model is developed to explore the relationships between various parameters and the output energy of CDEGs to efficiently and accurately predict the energy output of CDEGs.Based on the DNN model,optimal parameter designs for CDEGs are obtained by using non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ).The experiments verified that the FVP model predicts accurately the output energy of CDEG and the established optimal design framework can accurately provide the optimal design parameters of CDEG,which offers deep insights for the design and fabrication of a high-efficiency dielectric energy generator.
基金supported by the National Natural Science Foundation of China(Grant Nos.42272328 and 52108356).
文摘Cone penetration testing(CPT)and its variant with pore pressure measurements(CPTu)are versatile tools that have been traditionally used for in situ geotechnical site investigations.These investigations are among the most challenging yet indispensable tasks,providing a crucial reference for infrastructure planning,design and construction.However,data obtained through the CPT/CPTu testing often exhibit significant variability,even at closely spaced test points.This variability is primarily attributed to the complex mineral compositions and sedimentary process of the Quaternary sediments.Problems induced by the scattering data include the difficulties in estimating the shear strength of the sediments and determining the appropriate bearing stratum for pile foundations.In this paper,the conventional interpretation methods of the CPT/CPTu data are enhanced with sedimentary facies knowledge.The geotechnical investigation mainly involves 42 CPTu tests(39 essential data sets available)and 4 boring samples.Sediment types are interpreted from the CPTu data and calibrated by the nearby boring samples.Sedimentary facies are derived from the interpreted sequence stratigraphy,for which the interpretation skills are summarized in the form of characteristic curves of the CPTu data.Scattering distribution of the sediment types and their mechanical parameters are well explained by the sedimentary facies.The sediments are then categorized into a few groups by their sedimentary facies,resulting in reduced uncertainties and scattering in terms of shear strength.Bearing stratum of pile foundations is also suggested based on the sedimentary regulations.
