In view of globalization,the internationalization of basic education has become a world trend.It is an important strategic tool for each country to actively deal with the challenges of globalization,and it is also the...In view of globalization,the internationalization of basic education has become a world trend.It is an important strategic tool for each country to actively deal with the challenges of globalization,and it is also the main way to improve the quality of education around the world.The development of the internationalization of basic education requires the active participation of all countries around the world,in which it will have an impact and influence on the educational development,educational concept,and teaching management of all countries.However,only by conforming to the historical and inevitable trend of the internationalization of education,understanding the actual situation of the country's economic development,social development,and educational context,studying and implementing development strategies,as well as integrating healthy internationalization into the educational practice,then the internationalization of education can develop further so as to promote the rapid development of the whole world's education cause.展开更多
The outstanding performance of students in four Chinese provinces and municipalities in the Program for International Student Assessment(PISA)2018 is inextricably linked to local resource support,excellent education t...The outstanding performance of students in four Chinese provinces and municipalities in the Program for International Student Assessment(PISA)2018 is inextricably linked to local resource support,excellent education traditions,and ongoing curriculum and teaching reform.However,deepening education reform requires attention to existing challenges,including large inter-school gaps,the shortage of teachers in urban and rural areas,as well as students’heavy schoolwork burden and low level of well-being.Therefore,several policy suggestions are proposed accordingly:gaining insight into and developing higher quality and fairer education,pursuing effective actions of education reform,and exploring innovative pathways to address educational problems.展开更多
The issue of education for people with disabilities has become of increasing concern. How can we effectively guarantee the basic right to education for persons with disabilities? Will the revised Regulation on Educati...The issue of education for people with disabilities has become of increasing concern. How can we effectively guarantee the basic right to education for persons with disabilities? Will the revised Regulation on Education for Persons with Disabilities meet their needs? This article takes the Regulation on Education for Persons with Disabilities as the core and compares it with the related special educational laws of the United States, Britain and Japan. The following conclusions were drawn from this study: In terms of educational concept, the three countries follow the concept of inclusive education, and pursue equity and educational justice. They not only pay attention to inclusive education but also focus on improving the quality of education for students with disabilities. All three countries focus on accommodating children with special needs, but each implements its programs in a different way. These practices can be used as reference for the development of a special needs education law in China.展开更多
In recent years,with the high rate of juvenile delinquency,people pay more attention to the moral education of students in secondary vocational colleges.Based on the framework of social learning theory,this paper expl...In recent years,with the high rate of juvenile delinquency,people pay more attention to the moral education of students in secondary vocational colleges.Based on the framework of social learning theory,this paper explores the systematic and comprehensive application of social learning theory in the moral education course.From the cognition of the behavior to the selection and internalization of the representation of the model behavior,and finally the selective extemalization of the representation symbol to generate the behavior,the influencing factors and their utility in each stage of the production of moral behavior are analyzed step by step,assisting students to establish correct outlook on life and values,and cultivating their"key abilities."When students face a complex and diverse social environment,they can make judgments in line with the general moral standards of the society,and then seek to improve the effectiveness of the moral standards of secondary vocational students,and strive to maximize the effectiveness of moral education.展开更多
IL-33 and its receptor ST2 play crucial roles in tissue repair and homeostasis.However,their involvement in optic neuropathy due to trauma and glaucoma remains unclear.Here,we report that IL-33 and ST2 were highly exp...IL-33 and its receptor ST2 play crucial roles in tissue repair and homeostasis.However,their involvement in optic neuropathy due to trauma and glaucoma remains unclear.Here,we report that IL-33 and ST2 were highly expressed in the mouse optic nerve and retina.Deletion of IL-33 or ST2 exacerbated retinal ganglion cell(RGC)loss,retinal thinning,and nerve fiber degeneration following optic nerve(ON)injury.This heightened retinal neurodegeneration correlated with increased neurotoxic astrocytes in Il33-/-mice.In vitro,rIL-33 mitigated the neurotoxic astrocyte phenotype and reduced the expression of pro-inflammatory factors,thereby alleviating the RGC death induced by neurotoxic astrocyte-conditioned medium in retinal explants.Exogenous IL-33 treatment improved RGC survival in Il33-/-and WT mice after ON injury,but not in ST2-/-mice.Our findings highlight the role of the IL-33/ST2 axis in modulating reactive astrocyte function and providing neuroprotection for RGCs following ON injury.展开更多
Under investigation is the n-component nonlinear Schrödinger equation with higher-order effects,which describes the ultrashort pulses in the birefringent fiber.Based on the Lax pair,the eigenfunction and generali...Under investigation is the n-component nonlinear Schrödinger equation with higher-order effects,which describes the ultrashort pulses in the birefringent fiber.Based on the Lax pair,the eigenfunction and generalized Darboux transformation are derived.Next,we construct several novel higher-order localized waves and classified them into three categories:(i)higher-order rogue waves interacting with bright/antidark breathers,(ii)higher-order breather fission/fusion,(iii)higherorder breather interacting with soliton.Moreover,we explore the effects of parameters on the structure,collision process and energy distribution of localized waves and these characteristics are significantly different from previous ones.Finally,the dynamical properties of these solutions are discussed in detail.展开更多
Project construction and development are an impor-tant part of future army designs.In today’s world,intelligent war-fare and joint operations have become the dominant develop-ments in warfare,so the construction and ...Project construction and development are an impor-tant part of future army designs.In today’s world,intelligent war-fare and joint operations have become the dominant develop-ments in warfare,so the construction and development of the army need top-down,top-level design,and comprehensive plan-ning.The traditional project development model is no longer suf-ficient to meet the army’s complex capability requirements.Projects in various fields need to be developed and coordinated to form a joint force and improve the army’s combat effective-ness.At the same time,when a program consists of large-scale project data,the effectiveness of the traditional,precise mathe-matical planning method is greatly reduced because it is time-consuming,costly,and impractical.To solve above problems,this paper proposes a multi-stage program optimization model based on a heterogeneous network and hybrid genetic algo-rithm and verifies the effectiveness and feasibility of the model and algorithm through an example.The results show that the hybrid algorithm proposed in this paper is better than the exist-ing meta-heuristic algorithm.展开更多
Background:Theworld is nowexperiencing many crises and adversities of great impact that pose serious threats to both physical and mental health.Threats to mental health include major depressive disorder,which can be s...Background:Theworld is nowexperiencing many crises and adversities of great impact that pose serious threats to both physical and mental health.Threats to mental health include major depressive disorder,which can be severe and disabling.The current study aimed to identify the prevalence of one type of depressive disorder,reactive depression(RD),and its relationship to demographic and psychological variables.Methods:For this study,RD is defined as an abnormal emotional response to traumatic situations involving mood difficulties.This study created an online self-report reactive depression questionnaire consisting of 23 items distributed across three subscales:1)bad feelings and life attitudes,2)loss of hope and loneliness,and 3)feeling sad and loss of confidence.The questionnaire was administered to a volunteer sample of 362male and female Iraqi university students.Exploratory Factor Analysis(EFA),Confirmatory Factor Analysis(CFA),t-tests,and one-way Analysis of Variance(ANOVA)were used to investigate exploratory and confirmatory factor structures of the questionnaire.Results:Evidence of reactive depression was found in 18.2%of the students.Female students had significantly higher levels of reactive depression than males(female N=205,mean=85.00,SD=11.30;male N=157,mean=76.46,SD=11.51).The high levels of reactive depression identified in these students demonstrate the value of assessing reactive depression in university students.Conclusion:The study underscores that the loss of emotional and psychological security,particularly in the face of traumatic and permanent events such as the death of a loved one,may contribute to the onset and progression of depressive symptoms.Future research should explore the role of specific cultural factors and further validate the reactive depression questionnaire in broader populations.Additionally,there is a need for improvedmental health support in Iraqi universities,particularly for female students,who may face unique challenges.展开更多
Analytical solutions for the dynamic cylindrical cavity expansion in a com-pressible elastic-plastic cylinder with a finite radius are developed by taking into account of the effect of lateral free boundary, which are...Analytical solutions for the dynamic cylindrical cavity expansion in a com-pressible elastic-plastic cylinder with a finite radius are developed by taking into account of the effect of lateral free boundary, which are different from the traditional cavity expan-sion models for targets with infinite dimensions. The finite cylindrical cavity expansion process begins with an elastic-plastic stage followed by a plastic stage. The elastic-plastic stage ends and the plastic stage starts when the plastic wave front reaches the lateral free boundary. Approximate solutions of radial stress on cavity wall are derived by using the Von-Mise yield criterion and Forrestal’s similarity transformation method. The effects of the lateral free boundary and finite radius on the radial stress on the cavity wall are discussed, and comparisons are also conducted with the finite cylindrical cavity expansion in incompressible elastic-plastic materials. Numerical results show that the lateral free boundary has significant influence on the cavity expansion process and the radial stress on the cavity wall of metal cylinder with a finite radius.展开更多
Industrial agglomeration is an essential and effective way to integrate resources and elements. Its impact on the green innovation efficiency of the tourism industry is a process of continuous development and dynamic ...Industrial agglomeration is an essential and effective way to integrate resources and elements. Its impact on the green innovation efficiency of the tourism industry is a process of continuous development and dynamic change. This paper, based on the provincial panel data from 2006 to 2015, uses super SBM model to measure the green innovation efficiency of China's tourism industry.The threshold regression model is employed to conduct empirical tests of the nonlinear threshold effect of agglomeration on the green innovation efficiency of tourism industry. The inter-provincial differences of various threshold effects and their possible causes are analyzed. Results indicate that the green innovation efficiency of China's tourism industry is generally growing, while regional disparity is significant with a gradient decrease along the eastern-central-western regions. There is an obvious positive nonlinear relationship between tourism agglomeration and green innovation efficiency. It is also found that with the increase of agglomeration, its influence is at a high level. As the level of agglomeration crosses the first threshold, its impact is at a low level, and when it crosses the second threshold, the impact of tourism agglomeration is at an intermediate level. Finally, this paper proposes the basic path and some policy recommendations to promote the green innovation efficiency of the tourism industry in China.展开更多
The α-times integrated C semigroups, α > 0, are introduced and analyzed. The Laplace inverse transformation for α-times integrated C semigroups is obtained, some known results are generalized.
In this paper, the basic reproduction number is calculated for Huanglongbing (HLB) model with impulses which is a vector-borne epidemic model with impulses. For controlling HLB, farmers’ experience is replanting of h...In this paper, the basic reproduction number is calculated for Huanglongbing (HLB) model with impulses which is a vector-borne epidemic model with impulses. For controlling HLB, farmers’ experience is replanting of healthy plants and removing infected plants. To reflect the real world, we construct an impulsive control model which considers replanting of healthy plants and removing infected plants at one fixed time. By analyzing the model, we conclude that the disease-free equilibrium is globally asymptotically stable if the basic reproduction number Ro 1, and we prove that the HLB is permanence if the basic reproduction number Ro > 1.展开更多
To assess the water inflow which is more suitable to the actual conditions of tunnel,an empirical correlation about the permeability coefficient changing with depth is introduced.Supposing that the surrounding rock is...To assess the water inflow which is more suitable to the actual conditions of tunnel,an empirical correlation about the permeability coefficient changing with depth is introduced.Supposing that the surrounding rock is heterogeneous isotropy,the formula for calculating water inflow of tunnel with the nonlinear variation of permeability coefficient is deduced.By the contrast analysis with the existing formulas,the presented method has the similar value to them;moreover,the presented method has more simple form and easy to use.Due to parameter analysis,the water inflow decreases after considering the nonlinear variation of permeability coefficient.When the attenuation coefficient a>0,the water inflow increases first till reaches the maximum at a certain depth,then decreases and is close to 0 finally if deep enough.Thus,it is better to keep away from the certain depth where it is with the maximum water inflow for safe operation and economical construction,and reduce the water damage.Based on the analysis,the radius of tunnel has less impact on the amount of water inflow,and the water inflow just increases by 6.7% when the radius of tunnel increases by 1 m.展开更多
A three-dimensional（3-D） ocean model is coupled with a two-dimensional（2-D） sea ice model, to revisit a nonlinear advection mechanism, one of the most important mesoscale eddy genesis mechanisms in the marginal ic...A three-dimensional（3-D） ocean model is coupled with a two-dimensional（2-D） sea ice model, to revisit a nonlinear advection mechanism, one of the most important mesoscale eddy genesis mechanisms in the marginal ice zone. Two-dimensional ocean model simulations suggest nonlinear advection mechanism is more important when the water gets shallower. Instead of considering the ocean as barotropic fluid in the 2-D ocean model, the 3-D ocean model allows the sea ice to affect the current directly in the surface layer via ocean-ice interaction. It is found that both mesoscale eddy and sea surface elevation are sensitive to changes in a water depth in the 3-D simulations. The vertical profile of a current velocity in 3-D experiments suggests that when the water depth gets shallower, the current move faster in each layer, which makes the sea surface elevation be nearly inverse proportional to the water depth with the same wind forcing during the same time. It is also found that because of the vertical motion, the magnitude of variations in the sea surface elevation in the 3-D simulations is very small,being only 1% of the change in the 2-D simulations. And it seems the vertical motion to be the essential reason for the differences between the 3-D and 2-D experiments.展开更多
As a mainstream research direction in the field of image segmentation,medical image segmentation plays a key role in the quantification of lesions,three-dimensional reconstruction,region of interest extraction and so ...As a mainstream research direction in the field of image segmentation,medical image segmentation plays a key role in the quantification of lesions,three-dimensional reconstruction,region of interest extraction and so on.Compared with natural images,medical images have a variety of modes.Besides,the emphasis of information which is conveyed by images of different modes is quite different.Because it is time-consuming and inefficient to manually segment medical images only by professional and experienced doctors.Therefore,large quantities of automated medical image segmentation methods have been developed.However,until now,researchers have not developed a universal method for all types of medical image segmentation.This paper reviews the literature on segmentation techniques that have produced major breakthroughs in recent years.Among the large quantities of medical image segmentation methods,this paper mainly discusses two categories of medical image segmentation methods.One is the improved strategies based on traditional clustering method.The other is the research progress of the improved image segmentation network structure model based on U-Net.The power of technology proves that the performance of the deep learning-based method is significantly better than that of the traditional method.This paper discussed both advantages and disadvantages of different algorithms and detailed how these methods can be used for the segmentation of lesions or other organs and tissues,as well as possible technical trends for future work.展开更多
We investigate how the splicing mode of a holographic element(hogel)affects the reconstruction of a 3 D scene to improve the reconstruction resolution of a holographic stereogram fabricated using the effective perspec...We investigate how the splicing mode of a holographic element(hogel)affects the reconstruction of a 3 D scene to improve the reconstruction resolution of a holographic stereogram fabricated using the effective perspective image segmentation and mosaicking method(EPISM).First,the effect of hogel spatial multiplexing on holographic recording and reconstruction is studied based on the mechanism of recording interference fringes in the holographic recording medium.Second,combined with the influence of multiple exposures on the hologram's diffraction efficiency,the diffraction efficiency of the holographic stereogram is analyzed in the spatial multiplexing mode.The holographic stereogram is then regarded as a special optical imaging system.The theory of spatial bandwidth product is adopted to describe the comprehensive resolution of the holographic stereogram,which explains why hogel spatial multiplexing can significantly improve the reconstruction resolution of a holographic stereogram.Compared with the traditional printing method under the same parameters in optical experiments,hogel spatial multiplexing has a lower diffraction efficiency but a higher quality of reconstructed image,consistent with the theoretical analysis.展开更多
Feature selection is a crucial technique in text classification for improving the efficiency and effectiveness of classifiers or machine learning techniques by reducing the dataset’s dimensionality.This involves elim...Feature selection is a crucial technique in text classification for improving the efficiency and effectiveness of classifiers or machine learning techniques by reducing the dataset’s dimensionality.This involves eliminating irrelevant,redundant,and noisy features to streamline the classification process.Various methods,from single feature selection techniques to ensemble filter-wrapper methods,have been used in the literature.Metaheuristic algorithms have become popular due to their ability to handle optimization complexity and the continuous influx of text documents.Feature selection is inherently multi-objective,balancing the enhancement of feature relevance,accuracy,and the reduction of redundant features.This research presents a two-fold objective for feature selection.The first objective is to identify the top-ranked features using an ensemble of three multi-univariate filter methods:Information Gain(Infogain),Chi-Square(Chi^(2)),and Analysis of Variance(ANOVA).This aims to maximize feature relevance while minimizing redundancy.The second objective involves reducing the number of selected features and increasing accuracy through a hybrid approach combining Artificial Bee Colony(ABC)and Genetic Algorithms(GA).This hybrid method operates in a wrapper framework to identify the most informative subset of text features.Support Vector Machine(SVM)was employed as the performance evaluator for the proposed model,tested on two high-dimensional multiclass datasets.The experimental results demonstrated that the ensemble filter combined with the ABC+GA hybrid approach is a promising solution for text feature selection,offering superior performance compared to other existing feature selection algorithms.展开更多
This paper is concerned with the nonlinear Schrodinger-Kirchhoff system-(a+b∫R^3/u/^2dx)△u+λV(x)u=f(x,u)in R^3,where constants a>0,6≥0 andλ>0 is a parameter.We require that V(x)∈C(R^3)and has a potential w...This paper is concerned with the nonlinear Schrodinger-Kirchhoff system-(a+b∫R^3/u/^2dx)△u+λV(x)u=f(x,u)in R^3,where constants a>0,6≥0 andλ>0 is a parameter.We require that V(x)∈C(R^3)and has a potential well V^-1(0).Combining this with other suitable assumptions on K and f,the existence of nontrivial solutions is obtained via variational methods.Furthermore,the concentration behavior of the nontrivial solution is also explored on the set V^-1(0)asλ→+∞as A—>H-oo as well.It is worth noting that the(PS)-condition can not be directly got as done in the literature,which makes the problem more complicated.To overcome this difficulty,we adopt different method.展开更多
文摘In view of globalization,the internationalization of basic education has become a world trend.It is an important strategic tool for each country to actively deal with the challenges of globalization,and it is also the main way to improve the quality of education around the world.The development of the internationalization of basic education requires the active participation of all countries around the world,in which it will have an impact and influence on the educational development,educational concept,and teaching management of all countries.However,only by conforming to the historical and inevitable trend of the internationalization of education,understanding the actual situation of the country's economic development,social development,and educational context,studying and implementing development strategies,as well as integrating healthy internationalization into the educational practice,then the internationalization of education can develop further so as to promote the rapid development of the whole world's education cause.
文摘The outstanding performance of students in four Chinese provinces and municipalities in the Program for International Student Assessment(PISA)2018 is inextricably linked to local resource support,excellent education traditions,and ongoing curriculum and teaching reform.However,deepening education reform requires attention to existing challenges,including large inter-school gaps,the shortage of teachers in urban and rural areas,as well as students’heavy schoolwork burden and low level of well-being.Therefore,several policy suggestions are proposed accordingly:gaining insight into and developing higher quality and fairer education,pursuing effective actions of education reform,and exploring innovative pathways to address educational problems.
文摘The issue of education for people with disabilities has become of increasing concern. How can we effectively guarantee the basic right to education for persons with disabilities? Will the revised Regulation on Education for Persons with Disabilities meet their needs? This article takes the Regulation on Education for Persons with Disabilities as the core and compares it with the related special educational laws of the United States, Britain and Japan. The following conclusions were drawn from this study: In terms of educational concept, the three countries follow the concept of inclusive education, and pursue equity and educational justice. They not only pay attention to inclusive education but also focus on improving the quality of education for students with disabilities. All three countries focus on accommodating children with special needs, but each implements its programs in a different way. These practices can be used as reference for the development of a special needs education law in China.
文摘In recent years,with the high rate of juvenile delinquency,people pay more attention to the moral education of students in secondary vocational colleges.Based on the framework of social learning theory,this paper explores the systematic and comprehensive application of social learning theory in the moral education course.From the cognition of the behavior to the selection and internalization of the representation of the model behavior,and finally the selective extemalization of the representation symbol to generate the behavior,the influencing factors and their utility in each stage of the production of moral behavior are analyzed step by step,assisting students to establish correct outlook on life and values,and cultivating their"key abilities."When students face a complex and diverse social environment,they can make judgments in line with the general moral standards of the society,and then seek to improve the effectiveness of the moral standards of secondary vocational students,and strive to maximize the effectiveness of moral education.
基金supported by the National Natural Science Foundation of China(31670876 and 82171761).
文摘IL-33 and its receptor ST2 play crucial roles in tissue repair and homeostasis.However,their involvement in optic neuropathy due to trauma and glaucoma remains unclear.Here,we report that IL-33 and ST2 were highly expressed in the mouse optic nerve and retina.Deletion of IL-33 or ST2 exacerbated retinal ganglion cell(RGC)loss,retinal thinning,and nerve fiber degeneration following optic nerve(ON)injury.This heightened retinal neurodegeneration correlated with increased neurotoxic astrocytes in Il33-/-mice.In vitro,rIL-33 mitigated the neurotoxic astrocyte phenotype and reduced the expression of pro-inflammatory factors,thereby alleviating the RGC death induced by neurotoxic astrocyte-conditioned medium in retinal explants.Exogenous IL-33 treatment improved RGC survival in Il33-/-and WT mice after ON injury,but not in ST2-/-mice.Our findings highlight the role of the IL-33/ST2 axis in modulating reactive astrocyte function and providing neuroprotection for RGCs following ON injury.
基金Project supported by the National Natural Science Foundation of China(Grant No.12271096)the Natural Science Foundation of Fujian Province(Grant No.2021J01302)。
文摘Under investigation is the n-component nonlinear Schrödinger equation with higher-order effects,which describes the ultrashort pulses in the birefringent fiber.Based on the Lax pair,the eigenfunction and generalized Darboux transformation are derived.Next,we construct several novel higher-order localized waves and classified them into three categories:(i)higher-order rogue waves interacting with bright/antidark breathers,(ii)higher-order breather fission/fusion,(iii)higherorder breather interacting with soliton.Moreover,we explore the effects of parameters on the structure,collision process and energy distribution of localized waves and these characteristics are significantly different from previous ones.Finally,the dynamical properties of these solutions are discussed in detail.
基金supported by the National Natural Science Foundation of China(724701189072431011).
文摘Project construction and development are an impor-tant part of future army designs.In today’s world,intelligent war-fare and joint operations have become the dominant develop-ments in warfare,so the construction and development of the army need top-down,top-level design,and comprehensive plan-ning.The traditional project development model is no longer suf-ficient to meet the army’s complex capability requirements.Projects in various fields need to be developed and coordinated to form a joint force and improve the army’s combat effective-ness.At the same time,when a program consists of large-scale project data,the effectiveness of the traditional,precise mathe-matical planning method is greatly reduced because it is time-consuming,costly,and impractical.To solve above problems,this paper proposes a multi-stage program optimization model based on a heterogeneous network and hybrid genetic algo-rithm and verifies the effectiveness and feasibility of the model and algorithm through an example.The results show that the hybrid algorithm proposed in this paper is better than the exist-ing meta-heuristic algorithm.
文摘Background:Theworld is nowexperiencing many crises and adversities of great impact that pose serious threats to both physical and mental health.Threats to mental health include major depressive disorder,which can be severe and disabling.The current study aimed to identify the prevalence of one type of depressive disorder,reactive depression(RD),and its relationship to demographic and psychological variables.Methods:For this study,RD is defined as an abnormal emotional response to traumatic situations involving mood difficulties.This study created an online self-report reactive depression questionnaire consisting of 23 items distributed across three subscales:1)bad feelings and life attitudes,2)loss of hope and loneliness,and 3)feeling sad and loss of confidence.The questionnaire was administered to a volunteer sample of 362male and female Iraqi university students.Exploratory Factor Analysis(EFA),Confirmatory Factor Analysis(CFA),t-tests,and one-way Analysis of Variance(ANOVA)were used to investigate exploratory and confirmatory factor structures of the questionnaire.Results:Evidence of reactive depression was found in 18.2%of the students.Female students had significantly higher levels of reactive depression than males(female N=205,mean=85.00,SD=11.30;male N=157,mean=76.46,SD=11.51).The high levels of reactive depression identified in these students demonstrate the value of assessing reactive depression in university students.Conclusion:The study underscores that the loss of emotional and psychological security,particularly in the face of traumatic and permanent events such as the death of a loved one,may contribute to the onset and progression of depressive symptoms.Future research should explore the role of specific cultural factors and further validate the reactive depression questionnaire in broader populations.Additionally,there is a need for improvedmental health support in Iraqi universities,particularly for female students,who may face unique challenges.
基金Project supported by the Research Project of National University of Defense Technology(No.S130901)
文摘Analytical solutions for the dynamic cylindrical cavity expansion in a com-pressible elastic-plastic cylinder with a finite radius are developed by taking into account of the effect of lateral free boundary, which are different from the traditional cavity expan-sion models for targets with infinite dimensions. The finite cylindrical cavity expansion process begins with an elastic-plastic stage followed by a plastic stage. The elastic-plastic stage ends and the plastic stage starts when the plastic wave front reaches the lateral free boundary. Approximate solutions of radial stress on cavity wall are derived by using the Von-Mise yield criterion and Forrestal’s similarity transformation method. The effects of the lateral free boundary and finite radius on the radial stress on the cavity wall are discussed, and comparisons are also conducted with the finite cylindrical cavity expansion in incompressible elastic-plastic materials. Numerical results show that the lateral free boundary has significant influence on the cavity expansion process and the radial stress on the cavity wall of metal cylinder with a finite radius.
基金supported by National Social Science Foundation of China "Quality of China's Tourism Economic Growth and Its Spatial Analysis"[Grant number:17FGL005]Social Science Planning Fund Program of Shandong Province "Research on the Mechanism of Dynamic Energy Conversion to Promote the Optimization of Tourism Industrial Structure in Shandong Province"[Grant Number:17CLYJ40]Social Science Planning Fund Program of Qingdao City "The Way of Improving the Quality of Tourism Economic Growth in Qingdao"[Grant Number:QDSKLl701014]
文摘Industrial agglomeration is an essential and effective way to integrate resources and elements. Its impact on the green innovation efficiency of the tourism industry is a process of continuous development and dynamic change. This paper, based on the provincial panel data from 2006 to 2015, uses super SBM model to measure the green innovation efficiency of China's tourism industry.The threshold regression model is employed to conduct empirical tests of the nonlinear threshold effect of agglomeration on the green innovation efficiency of tourism industry. The inter-provincial differences of various threshold effects and their possible causes are analyzed. Results indicate that the green innovation efficiency of China's tourism industry is generally growing, while regional disparity is significant with a gradient decrease along the eastern-central-western regions. There is an obvious positive nonlinear relationship between tourism agglomeration and green innovation efficiency. It is also found that with the increase of agglomeration, its influence is at a high level. As the level of agglomeration crosses the first threshold, its impact is at a low level, and when it crosses the second threshold, the impact of tourism agglomeration is at an intermediate level. Finally, this paper proposes the basic path and some policy recommendations to promote the green innovation efficiency of the tourism industry in China.
文摘The α-times integrated C semigroups, α > 0, are introduced and analyzed. The Laplace inverse transformation for α-times integrated C semigroups is obtained, some known results are generalized.
文摘In this paper, the basic reproduction number is calculated for Huanglongbing (HLB) model with impulses which is a vector-borne epidemic model with impulses. For controlling HLB, farmers’ experience is replanting of healthy plants and removing infected plants. To reflect the real world, we construct an impulsive control model which considers replanting of healthy plants and removing infected plants at one fixed time. By analyzing the model, we conclude that the disease-free equilibrium is globally asymptotically stable if the basic reproduction number Ro 1, and we prove that the HLB is permanence if the basic reproduction number Ro > 1.
基金Projects(51478477,51508562,51508563)supported by the National Natural Science Foundation of China
文摘To assess the water inflow which is more suitable to the actual conditions of tunnel,an empirical correlation about the permeability coefficient changing with depth is introduced.Supposing that the surrounding rock is heterogeneous isotropy,the formula for calculating water inflow of tunnel with the nonlinear variation of permeability coefficient is deduced.By the contrast analysis with the existing formulas,the presented method has the similar value to them;moreover,the presented method has more simple form and easy to use.Due to parameter analysis,the water inflow decreases after considering the nonlinear variation of permeability coefficient.When the attenuation coefficient a>0,the water inflow increases first till reaches the maximum at a certain depth,then decreases and is close to 0 finally if deep enough.Thus,it is better to keep away from the certain depth where it is with the maximum water inflow for safe operation and economical construction,and reduce the water damage.Based on the analysis,the radius of tunnel has less impact on the amount of water inflow,and the water inflow just increases by 6.7% when the radius of tunnel increases by 1 m.
文摘A three-dimensional（3-D） ocean model is coupled with a two-dimensional（2-D） sea ice model, to revisit a nonlinear advection mechanism, one of the most important mesoscale eddy genesis mechanisms in the marginal ice zone. Two-dimensional ocean model simulations suggest nonlinear advection mechanism is more important when the water gets shallower. Instead of considering the ocean as barotropic fluid in the 2-D ocean model, the 3-D ocean model allows the sea ice to affect the current directly in the surface layer via ocean-ice interaction. It is found that both mesoscale eddy and sea surface elevation are sensitive to changes in a water depth in the 3-D simulations. The vertical profile of a current velocity in 3-D experiments suggests that when the water depth gets shallower, the current move faster in each layer, which makes the sea surface elevation be nearly inverse proportional to the water depth with the same wind forcing during the same time. It is also found that because of the vertical motion, the magnitude of variations in the sea surface elevation in the 3-D simulations is very small,being only 1% of the change in the 2-D simulations. And it seems the vertical motion to be the essential reason for the differences between the 3-D and 2-D experiments.
基金supported partly by the Open Project of State Key Laboratory of Millimeter Wave under Grant K202218partly by Innovation and Entrepreneurship Training Program of College Students under Grants 202210700006Y and 202210700005Z.
文摘As a mainstream research direction in the field of image segmentation,medical image segmentation plays a key role in the quantification of lesions,three-dimensional reconstruction,region of interest extraction and so on.Compared with natural images,medical images have a variety of modes.Besides,the emphasis of information which is conveyed by images of different modes is quite different.Because it is time-consuming and inefficient to manually segment medical images only by professional and experienced doctors.Therefore,large quantities of automated medical image segmentation methods have been developed.However,until now,researchers have not developed a universal method for all types of medical image segmentation.This paper reviews the literature on segmentation techniques that have produced major breakthroughs in recent years.Among the large quantities of medical image segmentation methods,this paper mainly discusses two categories of medical image segmentation methods.One is the improved strategies based on traditional clustering method.The other is the research progress of the improved image segmentation network structure model based on U-Net.The power of technology proves that the performance of the deep learning-based method is significantly better than that of the traditional method.This paper discussed both advantages and disadvantages of different algorithms and detailed how these methods can be used for the segmentation of lesions or other organs and tissues,as well as possible technical trends for future work.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFB1104500)the National Natural Science Foundation of China(Grant No.61775240)the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.201432)。
文摘We investigate how the splicing mode of a holographic element(hogel)affects the reconstruction of a 3 D scene to improve the reconstruction resolution of a holographic stereogram fabricated using the effective perspective image segmentation and mosaicking method(EPISM).First,the effect of hogel spatial multiplexing on holographic recording and reconstruction is studied based on the mechanism of recording interference fringes in the holographic recording medium.Second,combined with the influence of multiple exposures on the hologram's diffraction efficiency,the diffraction efficiency of the holographic stereogram is analyzed in the spatial multiplexing mode.The holographic stereogram is then regarded as a special optical imaging system.The theory of spatial bandwidth product is adopted to describe the comprehensive resolution of the holographic stereogram,which explains why hogel spatial multiplexing can significantly improve the reconstruction resolution of a holographic stereogram.Compared with the traditional printing method under the same parameters in optical experiments,hogel spatial multiplexing has a lower diffraction efficiency but a higher quality of reconstructed image,consistent with the theoretical analysis.
基金supported by Universiti Sains Malaysia(USM)and School of Computer Sciences,USM。
文摘Feature selection is a crucial technique in text classification for improving the efficiency and effectiveness of classifiers or machine learning techniques by reducing the dataset’s dimensionality.This involves eliminating irrelevant,redundant,and noisy features to streamline the classification process.Various methods,from single feature selection techniques to ensemble filter-wrapper methods,have been used in the literature.Metaheuristic algorithms have become popular due to their ability to handle optimization complexity and the continuous influx of text documents.Feature selection is inherently multi-objective,balancing the enhancement of feature relevance,accuracy,and the reduction of redundant features.This research presents a two-fold objective for feature selection.The first objective is to identify the top-ranked features using an ensemble of three multi-univariate filter methods:Information Gain(Infogain),Chi-Square(Chi^(2)),and Analysis of Variance(ANOVA).This aims to maximize feature relevance while minimizing redundancy.The second objective involves reducing the number of selected features and increasing accuracy through a hybrid approach combining Artificial Bee Colony(ABC)and Genetic Algorithms(GA).This hybrid method operates in a wrapper framework to identify the most informative subset of text features.Support Vector Machine(SVM)was employed as the performance evaluator for the proposed model,tested on two high-dimensional multiclass datasets.The experimental results demonstrated that the ensemble filter combined with the ABC+GA hybrid approach is a promising solution for text feature selection,offering superior performance compared to other existing feature selection algorithms.
基金Supported by the Youth Foundation of Shangqiu Institute of Technology(2018XKQ01)。
文摘This paper is concerned with the nonlinear Schrodinger-Kirchhoff system-(a+b∫R^3/u/^2dx)△u+λV(x)u=f(x,u)in R^3,where constants a>0,6≥0 andλ>0 is a parameter.We require that V(x)∈C(R^3)and has a potential well V^-1(0).Combining this with other suitable assumptions on K and f,the existence of nontrivial solutions is obtained via variational methods.Furthermore,the concentration behavior of the nontrivial solution is also explored on the set V^-1(0)asλ→+∞as A—>H-oo as well.It is worth noting that the(PS)-condition can not be directly got as done in the literature,which makes the problem more complicated.To overcome this difficulty,we adopt different method.
