It is well known that the sufficient family of time-optimal paths for both Dubins' as well as Reeds-Shepp' s car models consist of the concatenation of circular arcs with maximum curvature and straight line se...It is well known that the sufficient family of time-optimal paths for both Dubins' as well as Reeds-Shepp' s car models consist of the concatenation of circular arcs with maximum curvature and straight line segments, all tangentially connected. These time-optimal solutions suffer from some drawbacks. Their discontinuous curvature profile, together with the wear and impairment on the control equipment that the bang-bang solutions induce, calls for ' smoother' and more supple reference paths to follow. Avoiding the bang-bang solutions also raises the robustness with respect to any possible uncertainties. In this paper, our main tool for generating these “nearly time-optimal” , but nevertheless continuous-curvature paths, is to use the Pontryagin Maximum Principle (PMP) and make an appropriate and cunning choice of the Lagrangian function. Despite some rewarding simulation results, this concept turns out to be numerically divergent at some instances. Upon a more careful investigation, it can be concluded that the problem at hand is nearly singular. This is seen by applying the PMP to Dubins car and studying the corresponding two point boundary value problem, which turn out to be singular. Realizing this, one is able to contradict the widespread belief that all the information about the motion of a mobile platform lies in the initial values of the auxiliary variables associated with the PMP. Keywords Time-optimal paths - Motion planning - Optimal control - Pontryagin maximum principle - UGV展开更多
Discussions on Chinese modernization are offering African countries both conceptual inspiration and practical references as they explore their own sustainable development paths.
Topological phases are governed by lattice symmetries,yet how different symmetry-breaking paths(SBPs)affect topological transitions remains insufficiently understood.Most existing studies rely on a single SBP,and addr...Topological phases are governed by lattice symmetries,yet how different symmetry-breaking paths(SBPs)affect topological transitions remains insufficiently understood.Most existing studies rely on a single SBP,and address only one bandgap,limiting independent control of multiple gaps.Here,we investigate multiple isolated Dirac points in a trefoil-knot-modified honeycomb lattice,and show that a single SBP generally inverts all relevant Dirac points simultaneously,whereas the tailored combinations of SBPs enable selective and programmable band inversion at targeted gaps.The excitation-dependent responses reveal strong modal selectivity.This capability is exploited to realize independently controllable multi-channel signal splitting,which is unattainable with a single SBP.The results enable SBPs as an effective design degree of freedom for programmable and reconfigurable topological elastic devices.展开更多
In order to track the desired path as fast as possible,a novel autonomous vehicle path tracking based on model predictive control(MPC)and PID speed control was proposed for high-speed automated vehicles considering th...In order to track the desired path as fast as possible,a novel autonomous vehicle path tracking based on model predictive control(MPC)and PID speed control was proposed for high-speed automated vehicles considering the constraints of vehicle physical limits,in which a forward-backward integration scheme was introduced to generate a time-optimal speed profile subject to the tire-road friction limit.Moreover,this scheme was further extended along one moving prediction window.In the MPC controller,the prediction model was an 8-degree-of-freedom(DOF)vehicle model,while the plant was a 14-DOF vehicle model.For lateral control,a sequence of optimal wheel steering angles was generated from the MPC controller;for longitudinal control,the total wheel torque was generated from the PID speed controller embedded in the MPC framework.The proposed controller was implemented in MATLAB considering arbitrary curves of continuously varying curvature as the reference trajectory.The simulation test results show that the tracking errors are small for vehicle lateral and longitudinal positions and the tracking performances for trajectory and speed are good using the proposed controller.Additionally,the case of extended implementation in one moving prediction window requires shorter travel time than the case implemented along the entire path.展开更多
To study the energy evolution and failure characteristics of saturated sandstone under unloading conditions,rock unloading tests under different stress paths were conducted.The energy evolution mechanism of the unload...To study the energy evolution and failure characteristics of saturated sandstone under unloading conditions,rock unloading tests under different stress paths were conducted.The energy evolution mechanism of the unloading failure of saturated sandstone was systematically explored from the perspectives of the stress path,the initial confining pressure,and the energy conversion rate.The results show that(1)before the peak stress,the elastic energy increases with an increase in deviatoric stress,while the dissipated energy slowly increases first.After the peak stress,the elastic energy decreases with the decrease of deviatoric stress,and the dissipated energy suddenly increases.The energy release intensity during rock failure is positively correlated with the axial stress.(2)When the initial confining pressure is below a certain threshold,the stress path is the main factor influencing the total energy difference.When the axial stress remains constant and the confining pressure is unloading,the total energy is more sensitive to changes in the confining pressure.When the axial stress remains constant,the compressive deformation ability of the rock cannot be significantly improved by the increase in the initial confining pressure.The initial confining pressure is positively correlated with the rock's energy storage limit.(3)The initial confining pressure increases the energy conversion rate of the rock;the initial confining pressure is positively correlated with the energy conversion rate;and the energy conversion rate has a high confining pressure effect.The increase in the axial stress has a much greater impact on the elastic energy than the confining pressure.(4)When the deviatoric stress is small,the confining pressure mainly plays a protective role.Compared with the case of triaxial compression paths,the rock damage is more severe under unloading paths,and compared with the case of constant axial stress,the rock damage is more severe under increasing axial stress.展开更多
In view of the series of problems found in the rural collective economic audit in Zhangdian District of Zibo City in the past five years,this study used empirical research methods to deeply analyze the current situati...In view of the series of problems found in the rural collective economic audit in Zhangdian District of Zibo City in the past five years,this study used empirical research methods to deeply analyze the current situation and existing problems of the village collective audit work.On this basis,typical cases were selected for in-depth analysis,the effects of different audit modes were compared,and the reliable paths to improve the efficiency of village collective audit were studied and considered.The results show that the social governance strategy plays a positive role in improving the efficiency of village collective audit.This study is expected to provide a reference for the improvement of village collective audit efficiency,and is of great significance to improve the village collective financial management and promote the improvement of the rural governance system.展开更多
The prioritization of financial infrastructure construction serves as a crucial guarantee for the high-quality development of small and micro enterprises.However,resolving the financing challenges of small and micro e...The prioritization of financial infrastructure construction serves as a crucial guarantee for the high-quality development of small and micro enterprises.However,resolving the financing challenges of small and micro enterprises is not a task to be accomplished overnight.It necessitates the establishment of a long-term mechanism,the acceleration of financial innovation,the gradual enhancement of the vitality of micro-entities,and the creation of a stable and healthy economic development environment.Therefore,the author first analyzes the current financing situation of small and micro enterprises,as well as the problems they face during the process of financial innovation enabling small and micro enterprises to access financing and solve their financing difficulties,such as insufficient technical support,an imperfect risk control system,incomplete information disclosure,and a lack of credit data.Subsequently,targeted paths for financial innovation are proposed,aiming to offer suggestions for solving the financing problems of small and micro enterprises.展开更多
With the deep integration of digitization and intelligence,smart teaching has become an important trend in the field of education.As a key link in cultivating professional nursing talents,higher nursing education face...With the deep integration of digitization and intelligence,smart teaching has become an important trend in the field of education.As a key link in cultivating professional nursing talents,higher nursing education faces new opportunities and challenges in the context of smart teaching.This article deeply explores the necessity of innovating higher nursing education in the context of smart teaching,analyzes the current problems in higher nursing education,and proposes specific innovation paths from the aspects of teaching philosophy,teaching mode,teaching resources,teacher team building,and evaluation system.The aim is to improve the quality of higher nursing education and provide theoretical references for cultivating high-quality nursing talents that meet the needs of smart healthcare.展开更多
With ESG disclosure getting more and more attention,the integration of ESG information in corporate financial reporting faces many challenges.This paper analyzes the measurement standard inconsistency,high cost of dat...With ESG disclosure getting more and more attention,the integration of ESG information in corporate financial reporting faces many challenges.This paper analyzes the measurement standard inconsistency,high cost of data collection,lack of audit and forensic standards,and lack of talents in the integration of financial reporting information in the ESG disclosure boom,and proposes a path to break through the situation from the levels of policy,technology,and talents,aiming to provide ideas for enterprises to realize the effective integration of ESG information and financial reporting,so as to enhance the quality of corporate disclosure and the ability to transfer value.展开更多
Outer-independent Roman domination on graphs originates from the defensive strategy of Ancient Rome,which is that if any city without an army is attacked,a neighboring city with two armies could mobilize an army to su...Outer-independent Roman domination on graphs originates from the defensive strategy of Ancient Rome,which is that if any city without an army is attacked,a neighboring city with two armies could mobilize an army to support it and any two cities that have no army cannot be adjacent.The outer-independent Roman domination on graphs is an attractive topic in graph theory,and the definition is described as follows.Given a graph G=(V,E),a function f:V(G)→{0,1,2}is an outer-independent Roman dominating function(OIRDF)if f satisfies that every vertex v∈V with f(v)=0 has at least one adjacent vertex u∈N(v)with f(u)=2,where N(v)is the open neighborhood of v,and the set V0={v|f(v)=0}is an independent set.The weight of an OIRDF f is w(f)=∑_(v∈V)f(v).The value of minf w(f)is the outerindependent Roman domination number of G,denoted asγoiR(G).This paper is devoted to the study of the outer-independent Roman domination number of the Cartesian product of paths P_(n)□P_(m).With the help of computer,we find some recursive OIRDFs and then we present an upper bound ofγoiR(P_(n)□P_(m)).Furthermore,we prove the lower bound ofγoiR(P_(n)□P_(m))(n≤3)is equal to the upper bound.Hence,we achieve the exact value ofγoiR(P_(n)□P_(m))for n≤3 and the upper bound ofγoiR(P_(n)□P_(m))for n≥4.展开更多
With the rapid development of private higher education,the construction of counselor teams in private universities has become increasingly important.This paper focuses on outstanding counselors in private universities...With the rapid development of private higher education,the construction of counselor teams in private universities has become increasingly important.This paper focuses on outstanding counselors in private universities,delving into their growth patterns and proposing targeted training paths based on this analysis.By reviewing relevant theories and analyzing case studies of excellent counselors,it is found that outstanding counselors in private universities exhibit stage-specific characteristics during their development,influenced by personal traits,school environment,career progression,and other factors.In terms of training approaches,efforts should be made to improve selection mechanisms,strengthen training systems,provide career development support,and create a positive work atmosphere,all aimed at enhancing the overall quality of the counselor team in private universities and better serving student growth and institutional development.展开更多
While Western modernization is often regarded as a dominant model of linear progress,existing theories frequently overlook the diversity of modernization paths and the underlying commonalities shared across them.The r...While Western modernization is often regarded as a dominant model of linear progress,existing theories frequently overlook the diversity of modernization paths and the underlying commonalities shared across them.The rise of alternative models,exemplified by Chinese path to modernization,underscores the potential for multiple trajectories of modernization and reveals three core elements that define these paths:building consensus on development,generating momentum for growth,and enhancing resilience to challenges.The success of Chinese path to modernization can be attributed to several key factors:the establishment of a national development consensus driven by the leadership of the Communist Party of China;the creation of development momentum through endogenous growth,optimal resource allocation,and a sustained commitment to reform and opening-up;and the strengthening of resilience via economic diversification,gradual reforms,and robust risk management strategies.In contrast,African nations present a distinct mix of traditional consensus governance and modern democratic practices,while actively engaging in development-security-governance nexus management and refining early warning and crisis management systems.These countries are exploring their own paths to modernization,informed by their unique socio-political contexts.Despite many differences in national conditions,exchanges of experiences between China and African countries-focused on development consensus,momentum,and resilience-can break the myth that“modernization equals Westernization”.Such exchanges can empower developing nations to pursue their own,independent,and context-specific routes toward modernization.展开更多
Synergistic reduction of carbon emissions and air pollution is the core means to address the two major strategic tasks of fundamentally improving the ecological environment and the‘Dual-carbon target’.The issue of s...Synergistic reduction of carbon emissions and air pollution is the core means to address the two major strategic tasks of fundamentally improving the ecological environment and the‘Dual-carbon target’.The issue of synergistic reduction at the provincial level needs to be addressed as a matter of urgency.Taking Henan Province,the largest economy in central China,as an example,this study uses environmentally extended input-output analysis and structural path analysis to identify the key sectors that contribute to CO_(2),SO_(2),and total particulate matter(TPM)emissions,and to sort out key emission pathways(e.g.,Final Demand→Sector…).The results indicate that S2(Mining of Fossil Energy),S10(Nonmetal Mineral Products),S11(Metal Smelting),S13(Power and Heat)and S17(Transportation)are mainly responsible for CO_(2),SO_(2),and TPM direct emissions on the production side,while S16(Construction),S12(Equipment)and S18(Services)account for more than 45%of CO_(2),SO_(2),and TPM embodied emissions on the consumption side.32 shared emission pathways are extracted from the top 100 pathways for CO_(2),SO_(2),and TPM emissions,which account for 27%-51%of total emissions in Henan Province.P9(Export→Nonmetal Mineral Products),P10(Export→Metal Smelting)and P21(Gross Capital Formation→Construction→Nonmetal Mineral Products)are the leading paths responsible for embodied emissions.The research results provide the foundation and guidance for well-designed mitigation policies,as well as a reference for better synergistic control in provinces facing similar situations.展开更多
Against the backdrop of the advancement of the“Double High Plan”and the deepening of the strategy for building a cultural powerhouse,aesthetic education in architectural interior design in higher vocational colleges...Against the backdrop of the advancement of the“Double High Plan”and the deepening of the strategy for building a cultural powerhouse,aesthetic education in architectural interior design in higher vocational colleges faces dual demands for“cultural empowerment”and“skill enhancement.”Currently,prominent issues exist in this field,such as superficial integration of regional culture,disconnection between aesthetic education and professional skill training,and a lack of systematic infiltration paths.This study primarily takes regional culture in Sichuan and Chongqing as research samples,employing literature research,mixed research methods,case analysis,and action research.By analyzing the current status and dilemmas of aesthetic education practices,it constructs a four-dimensional integrated infiltration path for aesthetic education encompassing“resources-implementation-guarantee-evaluation.”This research not only provides an operable practical paradigm for aesthetic education reform in design-related majors in higher vocational colleges but also supports the living transmission of regional culture in Sichuan and Chongqing.展开更多
During the development blasting of circular tunnels, the detonation of multiple blastholes arranged onconcentric circles induces a complex dynamic response in the surrounding rocks. This process involvesmultiple blast...During the development blasting of circular tunnels, the detonation of multiple blastholes arranged onconcentric circles induces a complex dynamic response in the surrounding rocks. This process involvesmultiple blast loadings, static stress unloadings, and stress redistributions. In this study, the dynamicstresses of the surrounding rocks during development blasting, considering multiple blasting-unloadingstages with exponential paths and triangular paths (linear simplified paths of exponential paths), aresolved based on the dynamic theory and the Fourier transform method. Then, a corresponding discreteelement model is established using particle flow code (PFC). The multiple-stage dynamic stress andfracture distribution under different in situ stress levels and lateral coefficients are investigated. Theoreticalresults indicate that the peak compressive stresses in the surrounding rocks induced by bothtriangular and exponential paths are equal, while the triangular path generates greater additional dynamictensile stresses, particularly in the circumferential direction, compared to the exponential path.Numerical results show that the exponential path causes less dynamic circumferential tensile damageand forms fewer radial fractures than the triangular path in the first few blast stages;conversely, itexacerbates the damage and instability in the final blasting-unloading stage and forms more circumferentialfractures. Furthermore, the in situ stress determines which of the two opposite effects isdominant. Therefore, when using overly simplified triangular paths to evaluate the stability of surroundingrocks, potential overestimation or underestimation caused by different failure mechanismsshould be considered. Specifically, under high horizontal and vertical stresses, the static stress redistributionwith layer-by-layer blasting suppresses dynamic circumferential tensile and radial compressivedamage. The damage evolution of surrounding rocks in multi-stage blasting under different in situstresses is summarized and classified according to the damage mechanism and characteristics, which canguide blasting and support design.展开更多
The Wiener index of a graph is defined to be the sum of the distances of all pairs of vertices in the graph.The kth power G^(k) of a graph G is the graph on V(G)and two vertices are adjacent if and only if their dista...The Wiener index of a graph is defined to be the sum of the distances of all pairs of vertices in the graph.The kth power G^(k) of a graph G is the graph on V(G)and two vertices are adjacent if and only if their distance in G is less or equal to k.In this paper,we computed the Wiener index of the kth power of paths and cycles for any k≥2.展开更多
In the new era,curriculum ideological and political education has become one of the core approaches for higher education to implement the fundamental task of moral education.Obstetrics and gynecology nursing is a prof...In the new era,curriculum ideological and political education has become one of the core approaches for higher education to implement the fundamental task of moral education.Obstetrics and gynecology nursing is a professional basic course for medical nursing majors,featuring professionalism,humanism,and sociality,which has a natural fit with the integration of curriculum ideological and political education.Based on the professional characteristics of obstetrics and gynecology nursing teaching,this paper constructs a“six-in-one”integration path from six dimensions:integration goals,element excavation,content penetration,method innovation,evaluation system,and teacher team construction.It provides a reference for cultivating obstetrics and gynecology nursing talents with both exquisite professional skills and noble professional literacy.展开更多
Rapidly-exploring Random Tree(RRT)and its variants have become foundational in path-planning research,yet in complex three-dimensional off-road environments their uniform blind sampling and limited safety guarantees l...Rapidly-exploring Random Tree(RRT)and its variants have become foundational in path-planning research,yet in complex three-dimensional off-road environments their uniform blind sampling and limited safety guarantees lead to slow convergence and force an unfavorable trade-off between path quality and traversal safety.To address these challenges,we introduce HS-APF-RRT*,a novel algorithm that fuses layered sampling,an enhanced Artificial Potential Field(APF),and a dynamic neighborhood-expansion mechanism.First,the workspace is hierarchically partitioned into macro,meso,and micro sampling layers,progressively biasing random samples toward safer,lower-energy regions.Second,we augment the traditional APF by incorporating a slope-dependent repulsive term,enabling stronger avoidance of steep obstacles.Third,a dynamic expansion strategy adaptively switches between 8 and 16 connected neighborhoods based on local obstacle density,striking an effective balance between search efficiency and collision-avoidance precision.In simulated off-road scenarios,HS-APF-RRT*is benchmarked against RRT*,GoalBiased RRT*,and APF-RRT*,and demonstrates significantly faster convergence,lower path-energy consumption,and enhanced safety margins.展开更多
Excavation causes stress redistribution and affects the stress path during the shearing process of rock.The shear strength of rock varies under different stress paths,and the presence of defects reduces the shear stre...Excavation causes stress redistribution and affects the stress path during the shearing process of rock.The shear strength of rock varies under different stress paths,and the presence of defects reduces the shear strength.To further investigate this phenomenon,this study investigates the shear behaviour of rocks with different shear surface integrities under the influenceof different stress paths through laboratory tests and numerical simulations.The results indicate that the shear strength depends on the stress path and a decrease in the shear surface integrity reduces the degree of dependence.The cohesion and friction angle of the Mohr‒Coulomb criterion decrease with weakening of the shear surface integrity.For different stress paths,the direct shear strength is always greater than that of other shear stress paths.The pattern of changes in the acoustic emission count and cumulative count indirectly reflectsthe above findings.Numerical simulations further indicate that the different principal stress states and normal suppression effects during the shearing process lead to changes in the factors of crack propagation,resulting in different mechanical behaviours under various stress paths.For rocks with different integrity levels,the main reason for the different path dependences of shear strength is that the size of the area affected by shear is different.Shear failure will concentrate on the shear plane when the normal inhibition effect is greater.This study explores the mechanism of rock shear behaviour,providing a theoretical basis for establishing more accurate constitutive models and strength criteria.展开更多
This paper develops a semi-analytical solution for pile penetration in natural soft clays using the strain path method(SPM).The stress-strain behavior of soils is characterized by the S-CLAY1S model,which can capture ...This paper develops a semi-analytical solution for pile penetration in natural soft clays using the strain path method(SPM).The stress-strain behavior of soils is characterized by the S-CLAY1S model,which can capture the anisotropic evolution and destructuring nature of soft clays.By integrating the S-CLAY1S model into the theoretical framework of the SPM,a set of ordinary differential equations is formulated with respect to the vertical coordinate of soil particles.The distribution of excess pore water pressure(EPWP)following pile installation is approximated through one-dimensional(1D)radial integration around the pile shaft.The distribution of stresses and EPWP,along with the evolution of fabric anisotropy within the soil surrounding the pile,is presented to illustrate the response of pile penetration in natural soft clays.The proposed solution is validated against existing theoretical solutions using the SPM and cavity expansion method(CEM),along with experimental data.The findings demonstrate that the SPM reveals lower radial effective stresses and EPWP at the pile shaft than that of CEM.Pile penetration alters the soil's anisotropic properties,inducing rotational hardening and affecting post-installation stress distribution.Soil destructuration eliminates bonding among particles near the pile,resulting in a complete disruption of soil structure at the pile surface,which is particularly pronounced for higher initial soil structure ratios.Minimal variation was observed in the three principal stresses and shear stress on the cone side surface as the angle increased from 18°to 60°,except for a slight reduction in EPWP.展开更多
文摘It is well known that the sufficient family of time-optimal paths for both Dubins' as well as Reeds-Shepp' s car models consist of the concatenation of circular arcs with maximum curvature and straight line segments, all tangentially connected. These time-optimal solutions suffer from some drawbacks. Their discontinuous curvature profile, together with the wear and impairment on the control equipment that the bang-bang solutions induce, calls for ' smoother' and more supple reference paths to follow. Avoiding the bang-bang solutions also raises the robustness with respect to any possible uncertainties. In this paper, our main tool for generating these “nearly time-optimal” , but nevertheless continuous-curvature paths, is to use the Pontryagin Maximum Principle (PMP) and make an appropriate and cunning choice of the Lagrangian function. Despite some rewarding simulation results, this concept turns out to be numerically divergent at some instances. Upon a more careful investigation, it can be concluded that the problem at hand is nearly singular. This is seen by applying the PMP to Dubins car and studying the corresponding two point boundary value problem, which turn out to be singular. Realizing this, one is able to contradict the widespread belief that all the information about the motion of a mobile platform lies in the initial values of the auxiliary variables associated with the PMP. Keywords Time-optimal paths - Motion planning - Optimal control - Pontryagin maximum principle - UGV
文摘Discussions on Chinese modernization are offering African countries both conceptual inspiration and practical references as they explore their own sustainable development paths.
基金Project supported by the National Natural Science Foundation of China(Nos.12232015 and12572106)the National Key R&D Program of China(Nos.2024YFB3408700,2024YFB3408701,2024YFB3408703)the Natural Science Foundation of Shaanxi Province of China(No.2023-JC-YB-073)。
文摘Topological phases are governed by lattice symmetries,yet how different symmetry-breaking paths(SBPs)affect topological transitions remains insufficiently understood.Most existing studies rely on a single SBP,and address only one bandgap,limiting independent control of multiple gaps.Here,we investigate multiple isolated Dirac points in a trefoil-knot-modified honeycomb lattice,and show that a single SBP generally inverts all relevant Dirac points simultaneously,whereas the tailored combinations of SBPs enable selective and programmable band inversion at targeted gaps.The excitation-dependent responses reveal strong modal selectivity.This capability is exploited to realize independently controllable multi-channel signal splitting,which is unattainable with a single SBP.The results enable SBPs as an effective design degree of freedom for programmable and reconfigurable topological elastic devices.
基金Project(20180608005600843855-19)supported by the International Graduate Exchange Program of Beijing Institute of Technology,China。
文摘In order to track the desired path as fast as possible,a novel autonomous vehicle path tracking based on model predictive control(MPC)and PID speed control was proposed for high-speed automated vehicles considering the constraints of vehicle physical limits,in which a forward-backward integration scheme was introduced to generate a time-optimal speed profile subject to the tire-road friction limit.Moreover,this scheme was further extended along one moving prediction window.In the MPC controller,the prediction model was an 8-degree-of-freedom(DOF)vehicle model,while the plant was a 14-DOF vehicle model.For lateral control,a sequence of optimal wheel steering angles was generated from the MPC controller;for longitudinal control,the total wheel torque was generated from the PID speed controller embedded in the MPC framework.The proposed controller was implemented in MATLAB considering arbitrary curves of continuously varying curvature as the reference trajectory.The simulation test results show that the tracking errors are small for vehicle lateral and longitudinal positions and the tracking performances for trajectory and speed are good using the proposed controller.Additionally,the case of extended implementation in one moving prediction window requires shorter travel time than the case implemented along the entire path.
基金Anhui Natural Science Foundation Youth Program,Grant/Award Number:2208085QE142National Natural Science Foundations of China,Grant/Award Numbers:52004003,52304073Opening Foundation of Anhui Province Key Laboratory of Building Structure and Underground Engineering,Grant/Award Number:KLBSUE-2022-04。
文摘To study the energy evolution and failure characteristics of saturated sandstone under unloading conditions,rock unloading tests under different stress paths were conducted.The energy evolution mechanism of the unloading failure of saturated sandstone was systematically explored from the perspectives of the stress path,the initial confining pressure,and the energy conversion rate.The results show that(1)before the peak stress,the elastic energy increases with an increase in deviatoric stress,while the dissipated energy slowly increases first.After the peak stress,the elastic energy decreases with the decrease of deviatoric stress,and the dissipated energy suddenly increases.The energy release intensity during rock failure is positively correlated with the axial stress.(2)When the initial confining pressure is below a certain threshold,the stress path is the main factor influencing the total energy difference.When the axial stress remains constant and the confining pressure is unloading,the total energy is more sensitive to changes in the confining pressure.When the axial stress remains constant,the compressive deformation ability of the rock cannot be significantly improved by the increase in the initial confining pressure.The initial confining pressure is positively correlated with the rock's energy storage limit.(3)The initial confining pressure increases the energy conversion rate of the rock;the initial confining pressure is positively correlated with the energy conversion rate;and the energy conversion rate has a high confining pressure effect.The increase in the axial stress has a much greater impact on the elastic energy than the confining pressure.(4)When the deviatoric stress is small,the confining pressure mainly plays a protective role.Compared with the case of triaxial compression paths,the rock damage is more severe under unloading paths,and compared with the case of constant axial stress,the rock damage is more severe under increasing axial stress.
文摘In view of the series of problems found in the rural collective economic audit in Zhangdian District of Zibo City in the past five years,this study used empirical research methods to deeply analyze the current situation and existing problems of the village collective audit work.On this basis,typical cases were selected for in-depth analysis,the effects of different audit modes were compared,and the reliable paths to improve the efficiency of village collective audit were studied and considered.The results show that the social governance strategy plays a positive role in improving the efficiency of village collective audit.This study is expected to provide a reference for the improvement of village collective audit efficiency,and is of great significance to improve the village collective financial management and promote the improvement of the rural governance system.
文摘The prioritization of financial infrastructure construction serves as a crucial guarantee for the high-quality development of small and micro enterprises.However,resolving the financing challenges of small and micro enterprises is not a task to be accomplished overnight.It necessitates the establishment of a long-term mechanism,the acceleration of financial innovation,the gradual enhancement of the vitality of micro-entities,and the creation of a stable and healthy economic development environment.Therefore,the author first analyzes the current financing situation of small and micro enterprises,as well as the problems they face during the process of financial innovation enabling small and micro enterprises to access financing and solve their financing difficulties,such as insufficient technical support,an imperfect risk control system,incomplete information disclosure,and a lack of credit data.Subsequently,targeted paths for financial innovation are proposed,aiming to offer suggestions for solving the financing problems of small and micro enterprises.
文摘With the deep integration of digitization and intelligence,smart teaching has become an important trend in the field of education.As a key link in cultivating professional nursing talents,higher nursing education faces new opportunities and challenges in the context of smart teaching.This article deeply explores the necessity of innovating higher nursing education in the context of smart teaching,analyzes the current problems in higher nursing education,and proposes specific innovation paths from the aspects of teaching philosophy,teaching mode,teaching resources,teacher team building,and evaluation system.The aim is to improve the quality of higher nursing education and provide theoretical references for cultivating high-quality nursing talents that meet the needs of smart healthcare.
文摘With ESG disclosure getting more and more attention,the integration of ESG information in corporate financial reporting faces many challenges.This paper analyzes the measurement standard inconsistency,high cost of data collection,lack of audit and forensic standards,and lack of talents in the integration of financial reporting information in the ESG disclosure boom,and proposes a path to break through the situation from the levels of policy,technology,and talents,aiming to provide ideas for enterprises to realize the effective integration of ESG information and financial reporting,so as to enhance the quality of corporate disclosure and the ability to transfer value.
文摘Outer-independent Roman domination on graphs originates from the defensive strategy of Ancient Rome,which is that if any city without an army is attacked,a neighboring city with two armies could mobilize an army to support it and any two cities that have no army cannot be adjacent.The outer-independent Roman domination on graphs is an attractive topic in graph theory,and the definition is described as follows.Given a graph G=(V,E),a function f:V(G)→{0,1,2}is an outer-independent Roman dominating function(OIRDF)if f satisfies that every vertex v∈V with f(v)=0 has at least one adjacent vertex u∈N(v)with f(u)=2,where N(v)is the open neighborhood of v,and the set V0={v|f(v)=0}is an independent set.The weight of an OIRDF f is w(f)=∑_(v∈V)f(v).The value of minf w(f)is the outerindependent Roman domination number of G,denoted asγoiR(G).This paper is devoted to the study of the outer-independent Roman domination number of the Cartesian product of paths P_(n)□P_(m).With the help of computer,we find some recursive OIRDFs and then we present an upper bound ofγoiR(P_(n)□P_(m)).Furthermore,we prove the lower bound ofγoiR(P_(n)□P_(m))(n≤3)is equal to the upper bound.Hence,we achieve the exact value ofγoiR(P_(n)□P_(m))for n≤3 and the upper bound ofγoiR(P_(n)□P_(m))for n≥4.
基金The Second Batch of Comprehensive Reform and Quality Construction Projects of Party Building and Ideological and Political Education in 2024“Research on the Growth Patterns and Training Path of Excellent Counselors in Private Colleges”(HKDS2024YB11)。
文摘With the rapid development of private higher education,the construction of counselor teams in private universities has become increasingly important.This paper focuses on outstanding counselors in private universities,delving into their growth patterns and proposing targeted training paths based on this analysis.By reviewing relevant theories and analyzing case studies of excellent counselors,it is found that outstanding counselors in private universities exhibit stage-specific characteristics during their development,influenced by personal traits,school environment,career progression,and other factors.In terms of training approaches,efforts should be made to improve selection mechanisms,strengthen training systems,provide career development support,and create a positive work atmosphere,all aimed at enhancing the overall quality of the counselor team in private universities and better serving student growth and institutional development.
基金This article forms part of the 2021 Major Bidding Project under the Special Research Program on Significant Historical Issues,supported by the Chinese Academy of History and funded by the National Social Science Foundation of China:“General History of Africa(Multi-Volume Edition)”(Grant No.LSYZD21022).
文摘While Western modernization is often regarded as a dominant model of linear progress,existing theories frequently overlook the diversity of modernization paths and the underlying commonalities shared across them.The rise of alternative models,exemplified by Chinese path to modernization,underscores the potential for multiple trajectories of modernization and reveals three core elements that define these paths:building consensus on development,generating momentum for growth,and enhancing resilience to challenges.The success of Chinese path to modernization can be attributed to several key factors:the establishment of a national development consensus driven by the leadership of the Communist Party of China;the creation of development momentum through endogenous growth,optimal resource allocation,and a sustained commitment to reform and opening-up;and the strengthening of resilience via economic diversification,gradual reforms,and robust risk management strategies.In contrast,African nations present a distinct mix of traditional consensus governance and modern democratic practices,while actively engaging in development-security-governance nexus management and refining early warning and crisis management systems.These countries are exploring their own paths to modernization,informed by their unique socio-political contexts.Despite many differences in national conditions,exchanges of experiences between China and African countries-focused on development consensus,momentum,and resilience-can break the myth that“modernization equals Westernization”.Such exchanges can empower developing nations to pursue their own,independent,and context-specific routes toward modernization.
基金supported by the National Natural Science Foundation of China(No.42001246)the Energy Foundation(No.G-2209-34120).
文摘Synergistic reduction of carbon emissions and air pollution is the core means to address the two major strategic tasks of fundamentally improving the ecological environment and the‘Dual-carbon target’.The issue of synergistic reduction at the provincial level needs to be addressed as a matter of urgency.Taking Henan Province,the largest economy in central China,as an example,this study uses environmentally extended input-output analysis and structural path analysis to identify the key sectors that contribute to CO_(2),SO_(2),and total particulate matter(TPM)emissions,and to sort out key emission pathways(e.g.,Final Demand→Sector…).The results indicate that S2(Mining of Fossil Energy),S10(Nonmetal Mineral Products),S11(Metal Smelting),S13(Power and Heat)and S17(Transportation)are mainly responsible for CO_(2),SO_(2),and TPM direct emissions on the production side,while S16(Construction),S12(Equipment)and S18(Services)account for more than 45%of CO_(2),SO_(2),and TPM embodied emissions on the consumption side.32 shared emission pathways are extracted from the top 100 pathways for CO_(2),SO_(2),and TPM emissions,which account for 27%-51%of total emissions in Henan Province.P9(Export→Nonmetal Mineral Products),P10(Export→Metal Smelting)and P21(Gross Capital Formation→Construction→Nonmetal Mineral Products)are the leading paths responsible for embodied emissions.The research results provide the foundation and guidance for well-designed mitigation policies,as well as a reference for better synergistic control in provinces facing similar situations.
基金a phased research result of the 2024 Chongqing Vocational Education Teaching Reform Research Project,“Exploration and Practice of the‘Dual-Subject Three-Stage Three-Integration’Model for Aesthetic Education Infiltration in Architectural Interior Design”(Z2241471).
文摘Against the backdrop of the advancement of the“Double High Plan”and the deepening of the strategy for building a cultural powerhouse,aesthetic education in architectural interior design in higher vocational colleges faces dual demands for“cultural empowerment”and“skill enhancement.”Currently,prominent issues exist in this field,such as superficial integration of regional culture,disconnection between aesthetic education and professional skill training,and a lack of systematic infiltration paths.This study primarily takes regional culture in Sichuan and Chongqing as research samples,employing literature research,mixed research methods,case analysis,and action research.By analyzing the current status and dilemmas of aesthetic education practices,it constructs a four-dimensional integrated infiltration path for aesthetic education encompassing“resources-implementation-guarantee-evaluation.”This research not only provides an operable practical paradigm for aesthetic education reform in design-related majors in higher vocational colleges but also supports the living transmission of regional culture in Sichuan and Chongqing.
基金supported by the National Natural Science Foundation of China(Grant Nos.51927808 and 41630642)the Postgraduate Innovation Fund Project of Hunan Province(Grant No.CX20200242).
文摘During the development blasting of circular tunnels, the detonation of multiple blastholes arranged onconcentric circles induces a complex dynamic response in the surrounding rocks. This process involvesmultiple blast loadings, static stress unloadings, and stress redistributions. In this study, the dynamicstresses of the surrounding rocks during development blasting, considering multiple blasting-unloadingstages with exponential paths and triangular paths (linear simplified paths of exponential paths), aresolved based on the dynamic theory and the Fourier transform method. Then, a corresponding discreteelement model is established using particle flow code (PFC). The multiple-stage dynamic stress andfracture distribution under different in situ stress levels and lateral coefficients are investigated. Theoreticalresults indicate that the peak compressive stresses in the surrounding rocks induced by bothtriangular and exponential paths are equal, while the triangular path generates greater additional dynamictensile stresses, particularly in the circumferential direction, compared to the exponential path.Numerical results show that the exponential path causes less dynamic circumferential tensile damageand forms fewer radial fractures than the triangular path in the first few blast stages;conversely, itexacerbates the damage and instability in the final blasting-unloading stage and forms more circumferentialfractures. Furthermore, the in situ stress determines which of the two opposite effects isdominant. Therefore, when using overly simplified triangular paths to evaluate the stability of surroundingrocks, potential overestimation or underestimation caused by different failure mechanismsshould be considered. Specifically, under high horizontal and vertical stresses, the static stress redistributionwith layer-by-layer blasting suppresses dynamic circumferential tensile and radial compressivedamage. The damage evolution of surrounding rocks in multi-stage blasting under different in situstresses is summarized and classified according to the damage mechanism and characteristics, which canguide blasting and support design.
基金Supported by National Natural Science Foundation of China(Grant No.12201471)the Special Foundation in Key Fields for Universities of Guangdong Province(Grant No.2022ZDZX1034).
文摘The Wiener index of a graph is defined to be the sum of the distances of all pairs of vertices in the graph.The kth power G^(k) of a graph G is the graph on V(G)and two vertices are adjacent if and only if their distance in G is less or equal to k.In this paper,we computed the Wiener index of the kth power of paths and cycles for any k≥2.
文摘In the new era,curriculum ideological and political education has become one of the core approaches for higher education to implement the fundamental task of moral education.Obstetrics and gynecology nursing is a professional basic course for medical nursing majors,featuring professionalism,humanism,and sociality,which has a natural fit with the integration of curriculum ideological and political education.Based on the professional characteristics of obstetrics and gynecology nursing teaching,this paper constructs a“six-in-one”integration path from six dimensions:integration goals,element excavation,content penetration,method innovation,evaluation system,and teacher team construction.It provides a reference for cultivating obstetrics and gynecology nursing talents with both exquisite professional skills and noble professional literacy.
基金supported in part by 14th Five Year National Key R&D Program Project(Project Number:2023YFB3211001)the National Natural Science Foundation of China(62273339,U24A201397).
文摘Rapidly-exploring Random Tree(RRT)and its variants have become foundational in path-planning research,yet in complex three-dimensional off-road environments their uniform blind sampling and limited safety guarantees lead to slow convergence and force an unfavorable trade-off between path quality and traversal safety.To address these challenges,we introduce HS-APF-RRT*,a novel algorithm that fuses layered sampling,an enhanced Artificial Potential Field(APF),and a dynamic neighborhood-expansion mechanism.First,the workspace is hierarchically partitioned into macro,meso,and micro sampling layers,progressively biasing random samples toward safer,lower-energy regions.Second,we augment the traditional APF by incorporating a slope-dependent repulsive term,enabling stronger avoidance of steep obstacles.Third,a dynamic expansion strategy adaptively switches between 8 and 16 connected neighborhoods based on local obstacle density,striking an effective balance between search efficiency and collision-avoidance precision.In simulated off-road scenarios,HS-APF-RRT*is benchmarked against RRT*,GoalBiased RRT*,and APF-RRT*,and demonstrates significantly faster convergence,lower path-energy consumption,and enhanced safety margins.
基金support from the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX24_2822)the Graduate Innovation Program of China University of Mining and Technology(Grant No.2024WLKXJ205)the National Natural Science Foundation of China(Grant No.52474157).
文摘Excavation causes stress redistribution and affects the stress path during the shearing process of rock.The shear strength of rock varies under different stress paths,and the presence of defects reduces the shear strength.To further investigate this phenomenon,this study investigates the shear behaviour of rocks with different shear surface integrities under the influenceof different stress paths through laboratory tests and numerical simulations.The results indicate that the shear strength depends on the stress path and a decrease in the shear surface integrity reduces the degree of dependence.The cohesion and friction angle of the Mohr‒Coulomb criterion decrease with weakening of the shear surface integrity.For different stress paths,the direct shear strength is always greater than that of other shear stress paths.The pattern of changes in the acoustic emission count and cumulative count indirectly reflectsthe above findings.Numerical simulations further indicate that the different principal stress states and normal suppression effects during the shearing process lead to changes in the factors of crack propagation,resulting in different mechanical behaviours under various stress paths.For rocks with different integrity levels,the main reason for the different path dependences of shear strength is that the size of the area affected by shear is different.Shear failure will concentrate on the shear plane when the normal inhibition effect is greater.This study explores the mechanism of rock shear behaviour,providing a theoretical basis for establishing more accurate constitutive models and strength criteria.
基金support from the National Natural Science Foundation of China(Grant No.42407256)the State Key Laboratory of Hydraulics and Mountain River Engineering,China(Grant No.SKHL2113)the Sichuan Science and Technology Program(Grant No.2024YFHZ0341).
文摘This paper develops a semi-analytical solution for pile penetration in natural soft clays using the strain path method(SPM).The stress-strain behavior of soils is characterized by the S-CLAY1S model,which can capture the anisotropic evolution and destructuring nature of soft clays.By integrating the S-CLAY1S model into the theoretical framework of the SPM,a set of ordinary differential equations is formulated with respect to the vertical coordinate of soil particles.The distribution of excess pore water pressure(EPWP)following pile installation is approximated through one-dimensional(1D)radial integration around the pile shaft.The distribution of stresses and EPWP,along with the evolution of fabric anisotropy within the soil surrounding the pile,is presented to illustrate the response of pile penetration in natural soft clays.The proposed solution is validated against existing theoretical solutions using the SPM and cavity expansion method(CEM),along with experimental data.The findings demonstrate that the SPM reveals lower radial effective stresses and EPWP at the pile shaft than that of CEM.Pile penetration alters the soil's anisotropic properties,inducing rotational hardening and affecting post-installation stress distribution.Soil destructuration eliminates bonding among particles near the pile,resulting in a complete disruption of soil structure at the pile surface,which is particularly pronounced for higher initial soil structure ratios.Minimal variation was observed in the three principal stresses and shear stress on the cone side surface as the angle increased from 18°to 60°,except for a slight reduction in EPWP.
