The present paper proposes three-dimensional model necessary to calculate the transient temperature field in a journal bearing submitted to a sudden change in speed and load and analyzes the bearing performance numeri...The present paper proposes three-dimensional model necessary to calculate the transient temperature field in a journal bearing submitted to a sudden change in speed and load and analyzes the bearing performance numerically. Thermal deformation of the bush and realistic thermal boundary conditions at oil and bush interface are considered. At each time step a Newton-Raphson method is used to solve the Reynolds equation, film thickness equation and the motion equation of the journal simultaneously to obtain the pressure distribution and the velocity of the journal center. Then the fluid film force is acquired through integral of fluid film force and the acceleration and position of the journal center are acquired through differences of the velocity. The energy equations of the oil film and the bush are solved simultaneously by using an efficient finite difference scheme. Then the transient three dimensional temperature field of the bearing is acquired by combining the energy equations and the Reynolds equation through the nodal temperature and pressure. It is found that the approaches introduced here converge quickly and save calculation time greatly.展开更多
The division operation is not frequent relatively in traditional applications, but it is increasingly indispensable and important in many modern applications. In this paper, the implementation of modified signed-digit...The division operation is not frequent relatively in traditional applications, but it is increasingly indispensable and important in many modern applications. In this paper, the implementation of modified signed-digit (MSD) floating-point division using Newton-Raphson method on the system of ternary optical computer (TOC) is studied. Since the addition of MSD floating-point is carry-free and the digit width of the system of TOC is large, it is easy to deal with the enough wide data and transform the division operation into multiplication and addition operations. And using data scan and truncation the problem of digits expansion is effectively solved in the range of error limit. The division gets the good results and the efficiency is high. The instance of MSD floating-point division shows that the method is feasible.展开更多
In order to obtain direct solutions of parallel manipulator without divergence in real time,a modified global Newton-Raphson(MGNR) algorithm was proposed for forward kinematics analysis of six-degree-of-freedom(DOF) p...In order to obtain direct solutions of parallel manipulator without divergence in real time,a modified global Newton-Raphson(MGNR) algorithm was proposed for forward kinematics analysis of six-degree-of-freedom(DOF) parallel manipulator.Based on geometrical frame of parallel manipulator,the highly nonlinear equations of kinematics were derived using analytical approach.The MGNR algorithm was developed for the nonlinear equations based on Tailor expansion and Newton-Raphson iteration.The procedure of MGNR algorithm was programmed in Matlab/Simulink and compiled to a real-time computer with Microsoft visual studio.NET for implementation.The performance of the MGNR algorithms for 6-DOF parallel manipulator was analyzed and confirmed.Applying the MGNR algorithm,the real generalized pose of moving platform is solved by using the set of given positions of actuators.The theoretical analysis and numerical results indicate that the presented method can achieve the numerical convergent solution in less than 1 ms with high accuracy(1×10-9 m in linear motion and 1×10-9 rad in angular motion),even the initial guess value is far from the root.展开更多
Applications of certain multi-parameter acceleration techniques used with themodified New-ton-Raphson (mN-R) methods to solve the nonlinear equations arising from rigid-plasticfinite element analysis are investigated....Applications of certain multi-parameter acceleration techniques used with themodified New-ton-Raphson (mN-R) methods to solve the nonlinear equations arising from rigid-plasticfinite element analysis are investigated. New modified multi-parameter techniques, developed fromCrisfield's multi-parameter methods, are utilized to solve these nonlinear equations. The numericalperformance of these techniques is compared with the standard Newton-Raphson method (sN-R),Crisfield's single parameter method (C1), Crisfield's two parameter method (C2) and Crisfield'sthree parameter method (C3). The new techniques do not involve additional residual force calculationand require little extra computational effort. In addition, they are more robust and efficient thanother existing acceleration techniques.展开更多
The current theory in NF EN 1995-1-1/NA of Eurocode 5, which is based on maximum deflection, has been investigated on softwoods. Therefore, this theory is not adapted for slender glulam beam columns made of tropical h...The current theory in NF EN 1995-1-1/NA of Eurocode 5, which is based on maximum deflection, has been investigated on softwoods. Therefore, this theory is not adapted for slender glulam beam columns made of tropical hardwood species from the Congo Basin. This maximum deflection is caused by a set of loads applied to the structure. However, Eurocode 5 doesn’t provide how to predict this deflection in case of long-term load for such structures. This can be done by studying load-displacement (P-Δ) behaviour of these structures while taking into account second order effects. To reach this goal, a nonlinear analysis has been performed on a three-dimensional beam column embedded on both ends. Since conducting experimental investigations on large span structural products is time-consuming and expensive especially in developing countries, a numerical model has been implemented using the Newton-Raphson method to predict load-displacement (P-Δ) curve on a slender glulam beam column made of tropical hardwood species. On one hand, the beam has been analyzed without wood connection. On the other hand, the beam has been analyzed with a bolted wood connection and a slotted-in steel plate. The load cases considered include self-weight and a uniformly applied long-term load. Combinations of serviceability limit states (SLS) and ultimate limit states (ULS) have also been considered, among other factors. A finite-element software RFEM 5 has been used to implement the model. The results showed that the use of steel can reduce displacement by 20.96%. Additionally, compared to the maximum deflection provided by Eurocode 5 for softwoods, hardwoods can exhibit an increasing rate of 85.63%. By harnessing the plastic resistance of steel, the bending resistance of wood can be increased by 32.94%.展开更多
Problems in mechanism analysis and synthesis and robotics lead naturally to systems of nonlinear equations. In this paper, an approach based on Newton Raphson method and the property of fractals is presented to obtain...Problems in mechanism analysis and synthesis and robotics lead naturally to systems of nonlinear equations. In this paper, an approach based on Newton Raphson method and the property of fractals is presented to obtaining all roots of equation. An example from plane mechanism synthesis is given to demonstrate the idea of the method.展开更多
This study presents an effective hybrid simulation approach for simulating broadband ground motion in complex near-fault locations.The approach utilizes a deterministic approach based on the spectral element method(SE...This study presents an effective hybrid simulation approach for simulating broadband ground motion in complex near-fault locations.The approach utilizes a deterministic approach based on the spectral element method(SEM),which is used to simulate low-frequency ground motion(f1 Hz).A fourth-order Butterworth filter with zero phase shift is employed for time-domain filtering of low-and high-frequency time series at a crossover frequency of 1 Hz,merging the low and high-frequency ground motions into a broadband time series.Taking an Ms 6.8 Luding earthquake,as an example,this hybrid method was used for a rapid and efficient simulation analysis of broadband ground motion in the region.The accuracy and efficiency of this hybrid method were verified through comparisons with actually observed station data and empirical attenuation curves.Deterministic method simulation results revealed the effects of mountainous topography,basin effects,nonlinear effects within the basin’s sedimentary layers,and a coupling interaction between the basin and the mountains.The findings are consistent with similar studies,showing that near-fault sedimentary basins significantly focus and amplify strong ground motion,and the soil’s nonlinear behavior in the basin influences ground motion to varying extents at different distances from the fault.The mountainous topography impacts the basin’s response to ground motion,leading to barrier effects.This research provides a scientific foundation for seismic zoning,urban planning,and seismic design in nearfault mountain basin regions.展开更多
Resistant starch(RS)comprises starch fractions that resist digestion in the small intestine and reach the colon,where they are fermented by the microbiota.Resistant starch harbors functional properties and healthpromo...Resistant starch(RS)comprises starch fractions that resist digestion in the small intestine and reach the colon,where they are fermented by the microbiota.Resistant starch harbors functional properties and healthpromoting ingredients that can regulate blood glucose and lipid levels,prevent cancer,and enhance the quality of life.Consequently,new technologies for the preparation of RS are continually being developed to support its industrial production.This review describes the structural and nutritional properties of RS and examines recent advancements in RS preparation methods.Emphasis is placed on how RS structure influences its properties and the physiological mechanisms in vivo.This review aims to stimulate further research into the preparation methods,functional characteristics,and utilization of RS,thereby supporting ongoing developments in the food industry.展开更多
Traditional targeted analyses often overlook unknown or emerging contaminants,highlighting the significance of nontarget and suspect screening approaches.A novel and high-sensitivity methodology for nontarget analysis...Traditional targeted analyses often overlook unknown or emerging contaminants,highlighting the significance of nontarget and suspect screening approaches.A novel and high-sensitivity methodology for nontarget analysis of organic pollutants in human serum was newly-developed based on gas chromatography coupled with quadrupole time-of-flight high-resolution mass spectrometry.The extraction protocol employing an acetonitrile-ethyl acetate(9:1,V:V)mixture significantly improved the extraction efficiency while minimizing matrix effect.A hybridized analytical strategy integrating nontarget and suspect screening was developed to achieve comprehensive identification and classification of pollutants,employing the National Institute of Standards and Technology(NIST)20 library and Agilent Technologies Personal Compound Database and Library(PCDL).This approach successfully characterized 273 organic contaminants spanning 12 categories,including polycyclic aromatic hydrocarbons(PAHs)and their derivatives,esters,and phenolic compounds in human serum,with a significant increase in detection specificity compared to conventional workflows.The methodology used serum samples of the workers from coking industry,revealing widespread contamination dominated by PAHs and PAH derivatives.Among the target analytes,three were identified solely by NIST and six solely by PCDL,indicating the complementary benefits of combining these different databases.Notably,this work reported the first confirmed detection of 2-naphthalenamine in human serum.This optimized approach demonstrates enhanced sensitivity and reliability in serum analysis,advancing biomonitoring capabilities and providing a deep understanding of human exposure to environmental pollutants.展开更多
Advancements in tumor immunotherapy highlight the significant potential of antibody drugs,a key category of biological agents,for treating cancer and autoimmune diseases.This paper begins by defining and classifying k...Advancements in tumor immunotherapy highlight the significant potential of antibody drugs,a key category of biological agents,for treating cancer and autoimmune diseases.This paper begins by defining and classifying key targets in tumor immunity,as well as discussing their structural and functional characteristics.Subsequently,it elaborates on innovative technologies for antibody drug screening,which,when integrated with contemporary molecular biology,biotechnology,and computational biology,have substantially enhanced the efficiency and accuracy of target identification and antibody drug screening processes.Despite the promising prospects of tumor immunotherapy,certain limitations persist in its practical implementation.In conclusion,this paper offers a comprehensive examination of the cutting-edge developments in tumor immunotherapy,focusing on the aspects of tumor immunotherapy itself,critical targets for immunotherapy,and novel technologies and methodologies for antibody screening.This analysis is crucial for advancing the field of tumor immunotherapy and for enhancing both therapeutic efficacy and safety.Furthermore,research and development(R&D)of antibody drugs in other domains,such as autoimmune and inflammatory diseases,can benefit from it.展开更多
This paper presents a highly efficient implicit unified gas-kinetic particle(IUGKP)method for obtaining steady-state solutions of multi-scale phonon transport.The method adapts and reinterprets the integral solution o...This paper presents a highly efficient implicit unified gas-kinetic particle(IUGKP)method for obtaining steady-state solutions of multi-scale phonon transport.The method adapts and reinterprets the integral solution of the Bhatnagar-Gross-Krook(BGK)equation for time-independent solutions.The distribution function at a given point is determined solely by the surrounding equilibrium states,where the corresponding macroscopic quantities are computed through a weighted sum of equilibrium distribution functions from neighboring spatial positions.From a particle perspective,changes in macroscopic quantities within a cell result from particle transport across cell interfaces.These particles are sampled according to the equilibrium state of their original cells,accounting for their mean free path as the traveling distance.The IUGKP method evolves the solution according to the physical relaxation time scale,achieving high efficiency in large Knudsen number regimes.To accelerate convergence for small Knudsen numbers,an inexact Newton iteration method is implemented,incorporating macroscopic equations for convergence acceleration in the near-diffusive limit.The method also addresses spatial-temporal inconsistency caused by relaxation time variations in physical space through the null-collision concept.Numerical tests demonstrate the method’s excellent performance in accelerating multi-scale phonon transport solutions,achieving speedups of one to two orders of magnitude.The IUGKP method proves to be an efficient and accurate computational tool for simulating multiscale non-equilibrium heat transfer,offering significant advantages over traditional methods in both numerical performance and physical applicability.展开更多
Traditional deterministic numerical simulation often has a poor prediction performance for landslide-induced wave run-up(LIWR)hazards,as it neglects the effects of uncertainty.The limitation for efficiently quantifyin...Traditional deterministic numerical simulation often has a poor prediction performance for landslide-induced wave run-up(LIWR)hazards,as it neglects the effects of uncertainty.The limitation for efficiently quantifying the uncertainties in primary parameters remains largely unsolved.In this study,we propose a probabilistic evaluation method,integrating the adaptive Kriging(AK)metamodel method and probability density evolution method(PDEM)based on generalized F-discrepancy.A Taylor expansion-based adaptive design strategy is applied to construct the global AK model over representative points generated by generalized F-discrepancy,thereby approximating the numerical physical response(i.e.,maximum LIWR).Using these approximate responses,the PDEM is used to compute the exceedance probabilities that LIWR heights exceed elements at risk based on a construction of virtual time,and then a probabilistic criterion is introduced to classify hazard zones.The proposed method is demonstrated via two examples:Example I,which possesses risk element(building),and Example Ⅱ with water-level variations.The results indicate that the proposed method has an acceptable performance(showing a 1.7%difference in exceedance probability compared to Monte Carlo simulation with 50,000 samples)with low computation cost(requiring 284 deterministic analyses).For two specific scenarios in this study,the wave induced by the landslide exhibits a solitary-like leading wave.The proposed probabilistic method provides promising prospects for quantifying LIWR uncertainties,and is helpful for direct,efficient,and low-cost quantification assessment of cascading hazards.展开更多
In recent years,meshless methods have been increasingly applied to the simulation of various engineering problems due to their inherent advantages over traditional mesh-based approaches,including greater flexibility,i...In recent years,meshless methods have been increasingly applied to the simulation of various engineering problems due to their inherent advantages over traditional mesh-based approaches,including greater flexibility,independence from predefined meshing,simpler adaptive analysis,improved automation,and suitability for complex problems.Several meshless methods have been used for porous media simulation,and are broadly categorized into collocation,global weak form and local weak form methods.In this study,a comprehensive comparison of the applicability of these three categories of meshless methods for simulating coupled flow and transport problems in porous media is presented.The Radial Point Collocation Method(RPCM)(strong form),the Element Free Galerkin Method(EFGM)(global weak form)and the Meshless Local Petrov Galerkin(MLPG)method(local weak form)are implemented and systematically compared.These methods are applied to the analysis of flow in a synthetic regular domain aquifer,flow and non-reactive contaminant transport in a synthetic irregular boundary porous media problem and groundwater flow in a field aquifer located in India.The simulated groundwater heads are compared with analytical solution,observed field data and results obtained from widely used MODFLOW-MT3DMS models.The deviation of the solutions from the analytical solution is in the range of O.67%to O.l6%for the hypothetical case study.For the field-scale case study,mean absolute error of 0.183%,0.18l%and 0.188%are obtained for the RPCM,EFGM and MLPG models,respectively,outperforming MODFLOW,which exhibits a deviation of 0.254%from observed values.Overall,the present study reaffirms the practical applicability of these meshless methods for real-world groundwater problems and provides valuable insights into the utilization of each category of meshless method,with respect to problem type,computational efficiency and accuracy requirements.展开更多
Structure-ice interaction problems have attracted increasing attention,yet accurately predicting the loads exerted by sea ice on ship hulls remains a significant challenge.Over the past few decades,various numerical m...Structure-ice interaction problems have attracted increasing attention,yet accurately predicting the loads exerted by sea ice on ship hulls remains a significant challenge.Over the past few decades,various numerical methods have been employed to simulate ice resistance on ships and evaluate their manoeuvrability during ice-structure interaction.Among these approaches,the circumferential crack method has demonstrated both high efficiency and accuracy.This paper provides a detailed introduction to the fundamental theory of this method,including the numerical modeling of different failure modes and the dynamic ice motion responses.Furthermore,it reviews existing studies on predicting ice resistance and assessing the manoeuvrability of icebreakers navigating through ice-covered regions using the circumferential crack method.Several recommendations for future research in this field are also presented.展开更多
Geological prospecting and the identification of adverse geological features are essential in tunnel construction,providing critical information to ensure safety and guide engineering decisions.As tunnel projects exte...Geological prospecting and the identification of adverse geological features are essential in tunnel construction,providing critical information to ensure safety and guide engineering decisions.As tunnel projects extend into deeper and more mountainous terrains,engineers face increasingly complex geological conditions,including high water pressure,intense geo-stress,elevated geothermal gradients,and active fault zones.These conditions pose substantial risks such as high-pressure water inrush,largescale collapses,and tunnel boring machine(TBM)blockages.Addressing these challenges requires advanced detection technologies capable of long-distance,high-precision,and intelligent assessments of adverse geology.This paper presents a comprehensive review of recent advancements in tunnel geological ahead prospecting methods.It summarizes the fundamental principles,technical maturity,key challenges,development trends,and real-world applications of various detection techniques.Airborne and semi-airborne geophysical methods enable large-scale reconnaissance for initial surveys in complex terrain.Tunnel-and borehole-based approaches offer high-resolution detection during excavation,including seismic ahead prospecting(SAP),TBM rock-breaking source seismic methods,fulltime-domain tunnel induced polarization(TIP),borehole electrical resistivity,and ground penetrating radar(GPR).To address scenarios involving multiple,coexisting adverse geologies,intelligent inversion and geological identification methods have been developed based on multi-source data fusion and artificial intelligence(AI)techniques.Overall,these advances significantly improve detection range,resolution,and geological characterization capabilities.The methods demonstrate strong adaptability to complex environments and provide reliable subsurface information,supporting safer and more efficient tunnel construction.展开更多
Liquid-containing structures,including steam generators,water-cooling systems,in-containment refueling water storage tanks,suppression tanks,and tritiated water storage facilities,are integral components of nuclear re...Liquid-containing structures,including steam generators,water-cooling systems,in-containment refueling water storage tanks,suppression tanks,and tritiated water storage facilities,are integral components of nuclear reactor systems and are crucial for ensuring operational safety and stability.Traditional seismic analysis methods often struggle to accurately predict the dynamic behavior of such structures,particularly under transient events such as earthquakes.This paper presents a comprehensive study that applies the hybrid Eulerian-Lagrangian method to analyze fluid-structure interactions within these structures.The efficacy of this method for capturing the complex dynamics induced by liquid movement is demonstrated through simulations conducted primarily in a vertical storage tank.A comparative analysis with traditional response-spectrum analysis methods underscores the limitations of conventional approaches,particularly in terms of accounting for nonlinear free-surface motions and dynamic velocity distributions.The structural response of the tank containing liquid calculated using the hybrid Eulerian-Lagrangian method is approximately twice that calculated using the response-spectrum method,whereas in the case of a tank without liquid,the response is the same.Additionally,a high dynamic stress distribution exists near the liquid level of the structure.This study addresses the intricate interplay between structural components and fluid dynamics,thereby extrapolating insights from tanks to enhance safety protocols and design considerations for future nuclear devices.展开更多
This paper presents a comparative study of the solid weighting functions within the text of the modified partially saturated method(MPSM),which is an effective fluid-solid boundary condition in the lattice Boltzmann-d...This paper presents a comparative study of the solid weighting functions within the text of the modified partially saturated method(MPSM),which is an effective fluid-solid boundary condition in the lattice Boltzmann-discrete element coupling method(LBM-DEM).In its original form,the solid weighting function is τ-dependent.Previous studies have shown that the computational drag is viscosity-dependent when using the τ-dependent solid weighting function to solve fluid-particle interactions.To address this issue,two modified solid weighting functions,namely,the higher-order function and the solid-coverage function,are proposed.Nevertheless,the literature lacks a comparison of these functions,especially for viscosity dependence.In this study,the solid weighting functions are implemented and tested through two benchmark multiphase configurations,i.e.,a sphere settling between two parallel plates and the‘drafting,kissing and tumbling’of two settling spheres.The computational accuracy,viscosity dependence and convergence of the two modified functions are validated and compared against the original τ-dependent function.The LBM-DEM-MPSM formulation is then applied to study the settling behavior of a particle pack with varying solid fractions in a narrow fracture,which highlights the potential of employing the LBM-DEM-MPSM approach to a broader range of fluid-particle systems.展开更多
This paper introduces an improved scheme based on the discrete velocity method.Specifically,the reconstruction of the velocity distribution function and numerical flux at the interface is founded on the solution of th...This paper introduces an improved scheme based on the discrete velocity method.Specifically,the reconstruction of the velocity distribution function and numerical flux at the interface is founded on the solution of the Bhatnagar-Gross-Krook equation along the characteristic line.The proposed method accurately considers molecular transport and collision effects at the interface,thereby enabling accurate modeling from rarefied to continuum flow regimes.Additionally,the implicit discretization of the microscopic equations and incorporation of macroscopic equations result in accelerated convergence properties for steady-state problems.The proposed numerical approach is validated through several cases,including Rayleigh flow,lid-driven cavity flow,flow past an NACA0012 airfoil,and supersonic flow around a sphere.Numerical results demonstrate that the proposed method can efficiently and accurately obtain multiscale flow properties.展开更多
The method of characteristics(MoC)is a well-established tool for lattice physics calculations,offering advantages such as accurate representation of both lattice geometry and boundary conditions.The flat source(FS)app...The method of characteristics(MoC)is a well-established tool for lattice physics calculations,offering advantages such as accurate representation of both lattice geometry and boundary conditions.The flat source(FS)approximation is the most commonly used approach,whereas the linear source(LS)approximation enhances the accuracy by preserving the higherorder spatial moments of the neutron source.However,determining the order of accuracy(OoA)for spatial discretization in the MoC is challenging,particularly for the LS approximation.This complexity arises because MoC employs two spatial meshes:the fission source region(FSR)mesh and a set of characteristic rays used to integrate the transport equation over the FSR mesh.In this study,we analyzed the spatial order of accuracy of the MoC in planar geometry for both FS and LS approximations in relation to the distributed source.Our theoretical predictions are consistent with the numerical results obtained using the Method of Manufactured Solutions(MMS).The results demonstrate that the FS approximation achieves second-order accuracy,whereas the LS approximation attains fourth-order accuracy.展开更多
During the operation of the drilling cuttings method,frequent occurrences of suction and sticking phenomena lead to the loss of drilling tools and failure to achieve the designed borehole depth.resulting in inaccurate...During the operation of the drilling cuttings method,frequent occurrences of suction and sticking phenomena lead to the loss of drilling tools and failure to achieve the designed borehole depth.resulting in inaccurate risk assessment for coal seam rockbursts.To address these challenges,a mechanical analysis of cuttings transport via the spiral drill pipe was conducted.This analysis identified the primary factors contributing to suction and sticking phenomena in spiral drill pipes and proposed a targeted approach for mitigating these issues.Based on this analysis,an intelligent drilling cuttings method drill rig(IDCMDR)was developed,and field experiments were conducted.The experimental results demonstrate that when suction occurs,adjusting the rotational and drilling speeds of the IDCMDR effectively controls the phenomenon.When sticking occurs,the stuck drill pipe can be addressed by injecting high-pressure gas into the borehole bottom through the hollow structure of the spiral drill pipe or by reversing its rotation.During operation,characteristic patterns in the needle movements of the thrust and torque hydraulic gauges on the IDCMDR enable the identification of suction and sticking phenomena.The development and field validation of the IDCMDR confirm the feasibility of the theoretically proposed mitigation methods.展开更多
摘要The present paper proposes three-dimensional model necessary to calculate the transient temperature field in a journal bearing submitted to a sudden change in speed and load and analyzes the bearing performance numerically. Thermal deformation of the bush and realistic thermal boundary conditions at oil and bush interface are considered. At each time step a Newton-Raphson method is used to solve the Reynolds equation, film thickness equation and the motion equation of the journal simultaneously to obtain the pressure distribution and the velocity of the journal center. Then the fluid film force is acquired through integral of fluid film force and the acceleration and position of the journal center are acquired through differences of the velocity. The energy equations of the oil film and the bush are solved simultaneously by using an efficient finite difference scheme. Then the transient three dimensional temperature field of the bearing is acquired by combining the energy equations and the Reynolds equation through the nodal temperature and pressure. It is found that the approaches introduced here converge quickly and save calculation time greatly.
基金Project supported by the Shanghai Leading Academic Discipline Project(Grant No.J50103)the National Natural Science Foundation of China(Grant No.61073049)
摘要The division operation is not frequent relatively in traditional applications, but it is increasingly indispensable and important in many modern applications. In this paper, the implementation of modified signed-digit (MSD) floating-point division using Newton-Raphson method on the system of ternary optical computer (TOC) is studied. Since the addition of MSD floating-point is carry-free and the digit width of the system of TOC is large, it is easy to deal with the enough wide data and transform the division operation into multiplication and addition operations. And using data scan and truncation the problem of digits expansion is effectively solved in the range of error limit. The division gets the good results and the efficiency is high. The instance of MSD floating-point division shows that the method is feasible.
基金Project(HgdJG00401D04) supported by National 921 Manned Space Project Foundation of ChinaProject(SKLRS200803B) supported by the Self-Planned Task Foundation of State Key Laboratory of Robotics and System (HIT) of China+1 种基金Project(CDAZ98502211) supported by China’s "World Class University (985)" Project FoundationProject(50975055) supported by the National Natural Science Foundation of China
摘要In order to obtain direct solutions of parallel manipulator without divergence in real time,a modified global Newton-Raphson(MGNR) algorithm was proposed for forward kinematics analysis of six-degree-of-freedom(DOF) parallel manipulator.Based on geometrical frame of parallel manipulator,the highly nonlinear equations of kinematics were derived using analytical approach.The MGNR algorithm was developed for the nonlinear equations based on Tailor expansion and Newton-Raphson iteration.The procedure of MGNR algorithm was programmed in Matlab/Simulink and compiled to a real-time computer with Microsoft visual studio.NET for implementation.The performance of the MGNR algorithms for 6-DOF parallel manipulator was analyzed and confirmed.Applying the MGNR algorithm,the real generalized pose of moving platform is solved by using the set of given positions of actuators.The theoretical analysis and numerical results indicate that the presented method can achieve the numerical convergent solution in less than 1 ms with high accuracy(1×10-9 m in linear motion and 1×10-9 rad in angular motion),even the initial guess value is far from the root.
摘要Applications of certain multi-parameter acceleration techniques used with themodified New-ton-Raphson (mN-R) methods to solve the nonlinear equations arising from rigid-plasticfinite element analysis are investigated. New modified multi-parameter techniques, developed fromCrisfield's multi-parameter methods, are utilized to solve these nonlinear equations. The numericalperformance of these techniques is compared with the standard Newton-Raphson method (sN-R),Crisfield's single parameter method (C1), Crisfield's two parameter method (C2) and Crisfield'sthree parameter method (C3). The new techniques do not involve additional residual force calculationand require little extra computational effort. In addition, they are more robust and efficient thanother existing acceleration techniques.
摘要The current theory in NF EN 1995-1-1/NA of Eurocode 5, which is based on maximum deflection, has been investigated on softwoods. Therefore, this theory is not adapted for slender glulam beam columns made of tropical hardwood species from the Congo Basin. This maximum deflection is caused by a set of loads applied to the structure. However, Eurocode 5 doesn’t provide how to predict this deflection in case of long-term load for such structures. This can be done by studying load-displacement (P-Δ) behaviour of these structures while taking into account second order effects. To reach this goal, a nonlinear analysis has been performed on a three-dimensional beam column embedded on both ends. Since conducting experimental investigations on large span structural products is time-consuming and expensive especially in developing countries, a numerical model has been implemented using the Newton-Raphson method to predict load-displacement (P-Δ) curve on a slender glulam beam column made of tropical hardwood species. On one hand, the beam has been analyzed without wood connection. On the other hand, the beam has been analyzed with a bolted wood connection and a slotted-in steel plate. The load cases considered include self-weight and a uniformly applied long-term load. Combinations of serviceability limit states (SLS) and ultimate limit states (ULS) have also been considered, among other factors. A finite-element software RFEM 5 has been used to implement the model. The results showed that the use of steel can reduce displacement by 20.96%. Additionally, compared to the maximum deflection provided by Eurocode 5 for softwoods, hardwoods can exhibit an increasing rate of 85.63%. By harnessing the plastic resistance of steel, the bending resistance of wood can be increased by 32.94%.
基金Supported by the National Natural Science Foundation of China(No.59975077)the Science Foundation of SWJTU(No.1999XM05)
摘要Problems in mechanism analysis and synthesis and robotics lead naturally to systems of nonlinear equations. In this paper, an approach based on Newton Raphson method and the property of fractals is presented to obtaining all roots of equation. An example from plane mechanism synthesis is given to demonstrate the idea of the method.
基金National Natural Science Foundation of China under Grant Nos.U2139208 and 52278516Key Laboratory of Earthquake Engineering and Engineering Vibration,China Earthquake Administration under Grant No.2024D15Key Laboratory of Soft Soil Characteristic and Engineering Environment,Tianjin Chengjian University under Grant No.2022SCEEKL003。
摘要This study presents an effective hybrid simulation approach for simulating broadband ground motion in complex near-fault locations.The approach utilizes a deterministic approach based on the spectral element method(SEM),which is used to simulate low-frequency ground motion(f1 Hz).A fourth-order Butterworth filter with zero phase shift is employed for time-domain filtering of low-and high-frequency time series at a crossover frequency of 1 Hz,merging the low and high-frequency ground motions into a broadband time series.Taking an Ms 6.8 Luding earthquake,as an example,this hybrid method was used for a rapid and efficient simulation analysis of broadband ground motion in the region.The accuracy and efficiency of this hybrid method were verified through comparisons with actually observed station data and empirical attenuation curves.Deterministic method simulation results revealed the effects of mountainous topography,basin effects,nonlinear effects within the basin’s sedimentary layers,and a coupling interaction between the basin and the mountains.The findings are consistent with similar studies,showing that near-fault sedimentary basins significantly focus and amplify strong ground motion,and the soil’s nonlinear behavior in the basin influences ground motion to varying extents at different distances from the fault.The mountainous topography impacts the basin’s response to ground motion,leading to barrier effects.This research provides a scientific foundation for seismic zoning,urban planning,and seismic design in nearfault mountain basin regions.
基金financially supported by the National Key Research and Development Program of China(2023YFD2100803)the National Natural Science Foundation of China(32372387)+2 种基金the Science and Technology Major Project of Heilongjiang China(2021ZX12B07)Collaborative Innovation Achievement Project of“Double First-class”Disciplines in Heilongjiang Province(LJGXCG202080LJGXCG202083)。
摘要Resistant starch(RS)comprises starch fractions that resist digestion in the small intestine and reach the colon,where they are fermented by the microbiota.Resistant starch harbors functional properties and healthpromoting ingredients that can regulate blood glucose and lipid levels,prevent cancer,and enhance the quality of life.Consequently,new technologies for the preparation of RS are continually being developed to support its industrial production.This review describes the structural and nutritional properties of RS and examines recent advancements in RS preparation methods.Emphasis is placed on how RS structure influences its properties and the physiological mechanisms in vivo.This review aims to stimulate further research into the preparation methods,functional characteristics,and utilization of RS,thereby supporting ongoing developments in the food industry.
基金supported by the National Key Research and Development Project(Nos.2023YFC3905102 and 2024YFC3713201)the National Natural Science Foundation of China(Nos.42207485 and 42407567).
摘要Traditional targeted analyses often overlook unknown or emerging contaminants,highlighting the significance of nontarget and suspect screening approaches.A novel and high-sensitivity methodology for nontarget analysis of organic pollutants in human serum was newly-developed based on gas chromatography coupled with quadrupole time-of-flight high-resolution mass spectrometry.The extraction protocol employing an acetonitrile-ethyl acetate(9:1,V:V)mixture significantly improved the extraction efficiency while minimizing matrix effect.A hybridized analytical strategy integrating nontarget and suspect screening was developed to achieve comprehensive identification and classification of pollutants,employing the National Institute of Standards and Technology(NIST)20 library and Agilent Technologies Personal Compound Database and Library(PCDL).This approach successfully characterized 273 organic contaminants spanning 12 categories,including polycyclic aromatic hydrocarbons(PAHs)and their derivatives,esters,and phenolic compounds in human serum,with a significant increase in detection specificity compared to conventional workflows.The methodology used serum samples of the workers from coking industry,revealing widespread contamination dominated by PAHs and PAH derivatives.Among the target analytes,three were identified solely by NIST and six solely by PCDL,indicating the complementary benefits of combining these different databases.Notably,this work reported the first confirmed detection of 2-naphthalenamine in human serum.This optimized approach demonstrates enhanced sensitivity and reliability in serum analysis,advancing biomonitoring capabilities and providing a deep understanding of human exposure to environmental pollutants.
基金supported by the National Natural Science Foundation of China National(Grant Nos:32470999,31970882,81773261,81903140,82041012,82322055,82421005,82473278,92169115)the Shanghai Rising-Star Program(Grant No.:23QA1405800)+3 种基金The Shanghai Outstanding Academic Leader Program(Grant No.:23XD1424800)the Shanghai Key Laboratory of Cell Engineering(Grant No.:14DZ2272300)Yizhang Outstanding Academic Leader Program(Grant No.:JCYZRC-B-008)Cross-disciplinary research fund project of the Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine(Grant No.:JCJC202410).
摘要Advancements in tumor immunotherapy highlight the significant potential of antibody drugs,a key category of biological agents,for treating cancer and autoimmune diseases.This paper begins by defining and classifying key targets in tumor immunity,as well as discussing their structural and functional characteristics.Subsequently,it elaborates on innovative technologies for antibody drug screening,which,when integrated with contemporary molecular biology,biotechnology,and computational biology,have substantially enhanced the efficiency and accuracy of target identification and antibody drug screening processes.Despite the promising prospects of tumor immunotherapy,certain limitations persist in its practical implementation.In conclusion,this paper offers a comprehensive examination of the cutting-edge developments in tumor immunotherapy,focusing on the aspects of tumor immunotherapy itself,critical targets for immunotherapy,and novel technologies and methodologies for antibody screening.This analysis is crucial for advancing the field of tumor immunotherapy and for enhancing both therapeutic efficacy and safety.Furthermore,research and development(R&D)of antibody drugs in other domains,such as autoimmune and inflammatory diseases,can benefit from it.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1004500)the National Science Foundation of China(Grant Nos.12172316,92371107,12302378,92371201,and 52506078)+1 种基金Hong Kong research grant council(Grant Nos.16301222 and 16208324)the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2025SYS-SYSZD-070)。
摘要This paper presents a highly efficient implicit unified gas-kinetic particle(IUGKP)method for obtaining steady-state solutions of multi-scale phonon transport.The method adapts and reinterprets the integral solution of the Bhatnagar-Gross-Krook(BGK)equation for time-independent solutions.The distribution function at a given point is determined solely by the surrounding equilibrium states,where the corresponding macroscopic quantities are computed through a weighted sum of equilibrium distribution functions from neighboring spatial positions.From a particle perspective,changes in macroscopic quantities within a cell result from particle transport across cell interfaces.These particles are sampled according to the equilibrium state of their original cells,accounting for their mean free path as the traveling distance.The IUGKP method evolves the solution according to the physical relaxation time scale,achieving high efficiency in large Knudsen number regimes.To accelerate convergence for small Knudsen numbers,an inexact Newton iteration method is implemented,incorporating macroscopic equations for convergence acceleration in the near-diffusive limit.The method also addresses spatial-temporal inconsistency caused by relaxation time variations in physical space through the null-collision concept.Numerical tests demonstrate the method’s excellent performance in accelerating multi-scale phonon transport solutions,achieving speedups of one to two orders of magnitude.The IUGKP method proves to be an efficient and accurate computational tool for simulating multiscale non-equilibrium heat transfer,offering significant advantages over traditional methods in both numerical performance and physical applicability.
基金supported by the Major International(Regional)Joint Research Project of the NSFC(Grant No.42020104006)the National Major ScientificInstruments and Equipment Development Projects of China(Grant No.41827808).
摘要Traditional deterministic numerical simulation often has a poor prediction performance for landslide-induced wave run-up(LIWR)hazards,as it neglects the effects of uncertainty.The limitation for efficiently quantifying the uncertainties in primary parameters remains largely unsolved.In this study,we propose a probabilistic evaluation method,integrating the adaptive Kriging(AK)metamodel method and probability density evolution method(PDEM)based on generalized F-discrepancy.A Taylor expansion-based adaptive design strategy is applied to construct the global AK model over representative points generated by generalized F-discrepancy,thereby approximating the numerical physical response(i.e.,maximum LIWR).Using these approximate responses,the PDEM is used to compute the exceedance probabilities that LIWR heights exceed elements at risk based on a construction of virtual time,and then a probabilistic criterion is introduced to classify hazard zones.The proposed method is demonstrated via two examples:Example I,which possesses risk element(building),and Example Ⅱ with water-level variations.The results indicate that the proposed method has an acceptable performance(showing a 1.7%difference in exceedance probability compared to Monte Carlo simulation with 50,000 samples)with low computation cost(requiring 284 deterministic analyses).For two specific scenarios in this study,the wave induced by the landslide exhibits a solitary-like leading wave.The proposed probabilistic method provides promising prospects for quantifying LIWR uncertainties,and is helpful for direct,efficient,and low-cost quantification assessment of cascading hazards.
摘要In recent years,meshless methods have been increasingly applied to the simulation of various engineering problems due to their inherent advantages over traditional mesh-based approaches,including greater flexibility,independence from predefined meshing,simpler adaptive analysis,improved automation,and suitability for complex problems.Several meshless methods have been used for porous media simulation,and are broadly categorized into collocation,global weak form and local weak form methods.In this study,a comprehensive comparison of the applicability of these three categories of meshless methods for simulating coupled flow and transport problems in porous media is presented.The Radial Point Collocation Method(RPCM)(strong form),the Element Free Galerkin Method(EFGM)(global weak form)and the Meshless Local Petrov Galerkin(MLPG)method(local weak form)are implemented and systematically compared.These methods are applied to the analysis of flow in a synthetic regular domain aquifer,flow and non-reactive contaminant transport in a synthetic irregular boundary porous media problem and groundwater flow in a field aquifer located in India.The simulated groundwater heads are compared with analytical solution,observed field data and results obtained from widely used MODFLOW-MT3DMS models.The deviation of the solutions from the analytical solution is in the range of O.67%to O.l6%for the hypothetical case study.For the field-scale case study,mean absolute error of 0.183%,0.18l%and 0.188%are obtained for the RPCM,EFGM and MLPG models,respectively,outperforming MODFLOW,which exhibits a deviation of 0.254%from observed values.Overall,the present study reaffirms the practical applicability of these meshless methods for real-world groundwater problems and provides valuable insights into the utilization of each category of meshless method,with respect to problem type,computational efficiency and accuracy requirements.
基金financially supported by the National Natural Science Foundation of China(Grant No.52171259)the National Key Technologies Research and Development Program(Grant No.2022YFE0107000)+1 种基金the High-tech Ship Research Project of the Ministry of Industry and Information Technology(Grant No.[2021]342)the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.52301331).
摘要Structure-ice interaction problems have attracted increasing attention,yet accurately predicting the loads exerted by sea ice on ship hulls remains a significant challenge.Over the past few decades,various numerical methods have been employed to simulate ice resistance on ships and evaluate their manoeuvrability during ice-structure interaction.Among these approaches,the circumferential crack method has demonstrated both high efficiency and accuracy.This paper provides a detailed introduction to the fundamental theory of this method,including the numerical modeling of different failure modes and the dynamic ice motion responses.Furthermore,it reviews existing studies on predicting ice resistance and assessing the manoeuvrability of icebreakers navigating through ice-covered regions using the circumferential crack method.Several recommendations for future research in this field are also presented.
基金supported by the National Natural Science Foundation of China(Grant Nos.52021005,52325904,and 51991391)。
摘要Geological prospecting and the identification of adverse geological features are essential in tunnel construction,providing critical information to ensure safety and guide engineering decisions.As tunnel projects extend into deeper and more mountainous terrains,engineers face increasingly complex geological conditions,including high water pressure,intense geo-stress,elevated geothermal gradients,and active fault zones.These conditions pose substantial risks such as high-pressure water inrush,largescale collapses,and tunnel boring machine(TBM)blockages.Addressing these challenges requires advanced detection technologies capable of long-distance,high-precision,and intelligent assessments of adverse geology.This paper presents a comprehensive review of recent advancements in tunnel geological ahead prospecting methods.It summarizes the fundamental principles,technical maturity,key challenges,development trends,and real-world applications of various detection techniques.Airborne and semi-airborne geophysical methods enable large-scale reconnaissance for initial surveys in complex terrain.Tunnel-and borehole-based approaches offer high-resolution detection during excavation,including seismic ahead prospecting(SAP),TBM rock-breaking source seismic methods,fulltime-domain tunnel induced polarization(TIP),borehole electrical resistivity,and ground penetrating radar(GPR).To address scenarios involving multiple,coexisting adverse geologies,intelligent inversion and geological identification methods have been developed based on multi-source data fusion and artificial intelligence(AI)techniques.Overall,these advances significantly improve detection range,resolution,and geological characterization capabilities.The methods demonstrate strong adaptability to complex environments and provide reliable subsurface information,supporting safer and more efficient tunnel construction.
基金supported by the Fusion Vacuum Electrophysics Device Design and Development Project(No.Y15HX11706)。
摘要Liquid-containing structures,including steam generators,water-cooling systems,in-containment refueling water storage tanks,suppression tanks,and tritiated water storage facilities,are integral components of nuclear reactor systems and are crucial for ensuring operational safety and stability.Traditional seismic analysis methods often struggle to accurately predict the dynamic behavior of such structures,particularly under transient events such as earthquakes.This paper presents a comprehensive study that applies the hybrid Eulerian-Lagrangian method to analyze fluid-structure interactions within these structures.The efficacy of this method for capturing the complex dynamics induced by liquid movement is demonstrated through simulations conducted primarily in a vertical storage tank.A comparative analysis with traditional response-spectrum analysis methods underscores the limitations of conventional approaches,particularly in terms of accounting for nonlinear free-surface motions and dynamic velocity distributions.The structural response of the tank containing liquid calculated using the hybrid Eulerian-Lagrangian method is approximately twice that calculated using the response-spectrum method,whereas in the case of a tank without liquid,the response is the same.Additionally,a high dynamic stress distribution exists near the liquid level of the structure.This study addresses the intricate interplay between structural components and fluid dynamics,thereby extrapolating insights from tanks to enhance safety protocols and design considerations for future nuclear devices.
基金supported by the National Natural Science Foundation of China (Grant No. 52304025)the Heilongjiang Provincial Natural Science Foundation of China (Grant No. YQ2024E010)the National Natural Science Foundation of China (Grant Nos. U23A20596 and U24B6004)
摘要This paper presents a comparative study of the solid weighting functions within the text of the modified partially saturated method(MPSM),which is an effective fluid-solid boundary condition in the lattice Boltzmann-discrete element coupling method(LBM-DEM).In its original form,the solid weighting function is τ-dependent.Previous studies have shown that the computational drag is viscosity-dependent when using the τ-dependent solid weighting function to solve fluid-particle interactions.To address this issue,two modified solid weighting functions,namely,the higher-order function and the solid-coverage function,are proposed.Nevertheless,the literature lacks a comparison of these functions,especially for viscosity dependence.In this study,the solid weighting functions are implemented and tested through two benchmark multiphase configurations,i.e.,a sphere settling between two parallel plates and the‘drafting,kissing and tumbling’of two settling spheres.The computational accuracy,viscosity dependence and convergence of the two modified functions are validated and compared against the original τ-dependent function.The LBM-DEM-MPSM formulation is then applied to study the settling behavior of a particle pack with varying solid fractions in a narrow fracture,which highlights the potential of employing the LBM-DEM-MPSM approach to a broader range of fluid-particle systems.
基金supported by the Key Project of the Natural Science Foundation of Heilongjiang Province(Grant No.ZL2024E013)the National Key R&D Program of China(Grant No.2022YFF0503500)+1 种基金the National Natural Science Foundation of China(Grant No.12072257)supported in part by the High Performance Computing Center of Central South University.
摘要This paper introduces an improved scheme based on the discrete velocity method.Specifically,the reconstruction of the velocity distribution function and numerical flux at the interface is founded on the solution of the Bhatnagar-Gross-Krook equation along the characteristic line.The proposed method accurately considers molecular transport and collision effects at the interface,thereby enabling accurate modeling from rarefied to continuum flow regimes.Additionally,the implicit discretization of the microscopic equations and incorporation of macroscopic equations result in accelerated convergence properties for steady-state problems.The proposed numerical approach is validated through several cases,including Rayleigh flow,lid-driven cavity flow,flow past an NACA0012 airfoil,and supersonic flow around a sphere.Numerical results demonstrate that the proposed method can efficiently and accurately obtain multiscale flow properties.
基金supported by the Stable Support Plan Program under Shenzhen Natural Science Fund(No.20220811012323001)the LingChuang Research Project of China National Nuclear Corporation(No.CNNC-LCKY-202266)+6 种基金the Shenzhen Key Laboratory of Nuclear and Radiation Safety of Shenzhen Science and Technology Innovation Commission(No.ZDSYS20230626091501002)the Pengcheng Peacock Plan Distinguished Talent project(No.827-000712)the Shenzhen Science and Technology Innovation Commission Key Technical Project(Nos.JSGG20220831110607013 and KJZD20231023100200001)the Foundation for Distinguished Young Talents in Higher Education of Guangdong(No.2023KQNCX065)the Teaching Reform Research Programs under Shenzhen University Contract(Nos.JG000066010107,JG000033090185,and JG2022072)the Teaching Reform Research Program under Guangdong Provincial Department of Education Contract(No.JG2024085)supported by the Consortium for Advanced Simulation of Light Water Reactors(http://gffzz228af71adddf4e8esqb6k906v6qob6xxo.ffgz.tsg.suse.edu.cn/),an Energy Innovation Hub(http://gffzzda0388b0bb3b4345hqb6k906v6qob6xxo.ffgz.tsg.suse.edu.cn/hubs)for Modeling and Simulation of Nuclear Reactors,under the U.S.Department of Energy Contract(No.DE-AC05-00OR22725)。
摘要The method of characteristics(MoC)is a well-established tool for lattice physics calculations,offering advantages such as accurate representation of both lattice geometry and boundary conditions.The flat source(FS)approximation is the most commonly used approach,whereas the linear source(LS)approximation enhances the accuracy by preserving the higherorder spatial moments of the neutron source.However,determining the order of accuracy(OoA)for spatial discretization in the MoC is challenging,particularly for the LS approximation.This complexity arises because MoC employs two spatial meshes:the fission source region(FSR)mesh and a set of characteristic rays used to integrate the transport equation over the FSR mesh.In this study,we analyzed the spatial order of accuracy of the MoC in planar geometry for both FS and LS approximations in relation to the distributed source.Our theoretical predictions are consistent with the numerical results obtained using the Method of Manufactured Solutions(MMS).The results demonstrate that the FS approximation achieves second-order accuracy,whereas the LS approximation attains fourth-order accuracy.
基金supported by the National Key Research and Development Program of China(No.2022YFC3004605)the National Natural Science Foundation of China(No.52374201)+1 种基金the Open Fund of the State Key Laboratory of Coalburst Theory and Prevention Technology National Mine Safety Administration(Preparatory)(No.KFJJ-2025-0024)the Young Scientists Fund of Liaoning Province(B Class)(No.2026JH6/101000017).
摘要During the operation of the drilling cuttings method,frequent occurrences of suction and sticking phenomena lead to the loss of drilling tools and failure to achieve the designed borehole depth.resulting in inaccurate risk assessment for coal seam rockbursts.To address these challenges,a mechanical analysis of cuttings transport via the spiral drill pipe was conducted.This analysis identified the primary factors contributing to suction and sticking phenomena in spiral drill pipes and proposed a targeted approach for mitigating these issues.Based on this analysis,an intelligent drilling cuttings method drill rig(IDCMDR)was developed,and field experiments were conducted.The experimental results demonstrate that when suction occurs,adjusting the rotational and drilling speeds of the IDCMDR effectively controls the phenomenon.When sticking occurs,the stuck drill pipe can be addressed by injecting high-pressure gas into the borehole bottom through the hollow structure of the spiral drill pipe or by reversing its rotation.During operation,characteristic patterns in the needle movements of the thrust and torque hydraulic gauges on the IDCMDR enable the identification of suction and sticking phenomena.The development and field validation of the IDCMDR confirm the feasibility of the theoretically proposed mitigation methods.