The flexible rolling process(FRP) is a novel three-dimensional(3 D) forming process that combines the multipoint and traditional rolling forming. The principle of FRP is based on thickness thinning, so the deformation...The flexible rolling process(FRP) is a novel three-dimensional(3 D) forming process that combines the multipoint and traditional rolling forming. The principle of FRP is based on thickness thinning, so the deformation path significantly impacts the forming effect. In this study, the multistep forming process with different deformation paths was introduced to improve the forming effect of FRP. For instance, with the convex surface part, three finite element models of multistep FRP(MSFRP) were established. The corresponding numerical simulations and forming experiments performed among different deformation paths showed the surface part with a longer effective forming region was obtained and the forming regions with more steps in MSFRP were smoother. Thus, the sheet-metal utilization rate was greatly improved. Moreover, the MSFRP can improve the longitudinal bending effect dramatically and thereby endowing the forming part with a better forming effect. Therefore, MSFRP is a prospective method for broad applications.展开更多
This paper investigates the development,the breakdown process,and the discharge path selection of the lightning discharges in two-phase mixtures(TPMs).13 kinds of solid-gas mixtures and 3 kinds of liquid-gas mixtures ...This paper investigates the development,the breakdown process,and the discharge path selection of the lightning discharges in two-phase mixtures(TPMs).13 kinds of solid-gas mixtures and 3 kinds of liquid-gas mixtures are employed to study effect of two phase mixtures on the selection of the discharge path under lightning impulses.Grain size effects are shown upon these experimental results.When the diameter of solid or liquid grains is less than about 10 μm,the discharge path does not select TPM but air.And the discharge path selects TPM when the diameter is greater than about 100 μm.And when the diameter is between about 10 μm and 100 μm,the discharge path selects TPM under negative lightning impulses,but it has a greater selection of air than TPMs under positive lightning impulses.Volume fraction and permittivity of solid/liquid can also influence the selection of the discharge path.展开更多
In the paper presented, 99 single seed descent barley lines as well as their parental forms Roland and Apex were studied. The grain weight components and their interrelations were analyzed using simple coefficients of...In the paper presented, 99 single seed descent barley lines as well as their parental forms Roland and Apex were studied. The grain weight components and their interrelations were analyzed using simple coefficients of correlation. The direct and indirect effects of such components on grain weight per plant and 1 000-grain weight were estimated using path analysis. In the 2006 and 2007, the spike length and number of spikelets per spike were the determinants of grain weight. Genetic parameters as additive and epistasis effects were estimated for all studied traits. The results indicate the importance of both additive and epistasis gene effects of number of spikes per plant, grain weight per spike, grain number per plant and grain weight per plant in this study.展开更多
At present,higher education in China has entered the stage of popularization,and the"connotative development of higher education"has become the inevitable choice for the development of colleges and universit...At present,higher education in China has entered the stage of popularization,and the"connotative development of higher education"has become the inevitable choice for the development of colleges and universities in China.In the process of"connotative development"in higher education,we must realize the importance of discipline construction and optimize discipline layout and specialty construction,improve the quality of personnel trained by colleges and universities in order to satisfy the needs of social and economic development.On this basis,colleges and universities should,according to the market demand for talents,reform and innovate the talent training mode,continuously strengthen the construction of teaching staff,improve the quality of classroom teaching,effectively improve students'social practice capability,improve the quality of talent training,and take a connotative development path through school-enterprise cooperation and integration of production and teaching.展开更多
The influence of loading path on tube hydroforming process is discussed in this paper with finiteelement simulation. Four different loading paths are utilized in simulating the forming process of square tubular compo...The influence of loading path on tube hydroforming process is discussed in this paper with finiteelement simulation. Four different loading paths are utilized in simulating the forming process of square tubular component with hydroforming and the result of different loading path is presented. Among the result. the thickness distribution of bilinear loading path is the most uniform one. It shows that the increase of punch displacement in the stage of high pressure is beneficial to the forming of component for optimized Stress condition.展开更多
This paper documents a study to examine the sensitivity to cloud droplet effective radius and liquid water path and the alleviation the energy imbalance at the top of the atmosphere and at the surface in the latest ve...This paper documents a study to examine the sensitivity to cloud droplet effective radius and liquid water path and the alleviation the energy imbalance at the top of the atmosphere and at the surface in the latest version of the Grid-point Atmospheric Model of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG）, Institute of Atmospheric Physics （IAP） （GAMIL1.1.0）. Considerable negative biases in all flux components, and thus an energy imbalance, are found in GAMIL1.1.0. In order to alleviate the energy imbalance, two modifications, namely an increase in cloud droplet effective radius and a decrease in cloud liquid water path, have been made to the cloud properties used in GAMIL. With the increased cloud droplet effective radius, the single scattering albedo of clouds is reduced, and thus the reflection of solar radiation into space by clouds is reduced and the net solar radiation flux at the top of the atmosphere is increased. With the reduced cloud optical depth, the net surface shortwave radiation flux is increased, causing a net warming over the land surface. This results in an increase in both sensible and latent heat fluxes over the land regions, which is largely balanced by the increased terrestrial radiation fluxes. Consequently, the energy balance at the top of atmosphere and at the surface is achieved with energy flux components consistent with available satellite observations.展开更多
The problem of insufficient agricultural input has been restricting China's agricultural development. When the expansion of the use of capital has become a bottleneck restricting the agricultural development,the e...The problem of insufficient agricultural input has been restricting China's agricultural development. When the expansion of the use of capital has become a bottleneck restricting the agricultural development,the effective use of agricultural input resources will become an important way to increase agricultural input. Through building the value chain of interactive development between urban agriculture and other industries,it is expected to promote the reasonable allocation of resources,realize the conservation of resources and increase the efficiency of resource utilization,and promote the urban agricultural input to become an effective input. In this way,it can realize the transformation of agricultural development and the innovation of financing method of urban agriculture.展开更多
Using the path integral formalism, the fine structure and dynamics effects are taken into account for the broadening of spectral lines in a plasma. A compact expression of the dipolar autocorrelation function for an e...Using the path integral formalism, the fine structure and dynamics effects are taken into account for the broadening of spectral lines in a plasma. A compact expression of the dipolar autocorrelation function for an emitter in the plasma is derived for Lyman alpha lines with fine structure. The expression of the dipolar autocorrelation function takes into account the dynamics effects, which are represented by the time microfield autocorrelation function.展开更多
This paper examines the rise of informal economies in China,a hidden driving force overlooked in studies on China’s urbanization.Estimating the size of informal economies using the multiple indicators multiple causes...This paper examines the rise of informal economies in China,a hidden driving force overlooked in studies on China’s urbanization.Estimating the size of informal economies using the multiple indicators multiple causes model,the paper employs mathematical models to examine the driving effect of informal economies on urbanization and to reveal the paths by which such effect works.The results were as follows.(1)In 2018,the size of the informal economy in China accounted for 23.5%of GDP with an output value of 21.16 trillion yuan.(2)The informal economy had a driving effect on China’s urbanization,and every 1-percentagepoint increase in its share of the GDP led to an increase of 0.291 percentage points in the urbanization rate.(3)The informal economy’s effect on urbanization showed regional differences,decreasing in size from the eastern to the central to the western regions.(4)The informal economy drives urbanization through four paths-by promoting foreign direct investment(FDI),fixed asset investment(FAI),social consumption(SC),and secondary sector employment(SSE).Their effect sizes are ranked in descending order as follows:FDI>FAI>SC>SSE.This paper contributes to theories on urbanization dynamics and process in China by highlighting the role of the informal economy as a hidden economic power lurking in the city.展开更多
The Kaiser effect is formally described as the absence of detectable acoustic emission （AE） events until the load imposed on the material exceeds the previous applied level and is usually used to estimate geostress....The Kaiser effect is formally described as the absence of detectable acoustic emission （AE） events until the load imposed on the material exceeds the previous applied level and is usually used to estimate geostress. By focusing on the heterogeneity of rock material, the mechanism of the Kaiser effect under cyclic loading is analyzed based on statistic damage mechanics. Two groups of granite specimens have been cyclically loaded with two different loading paths to verify the theoretical results. The heterogeneity of rock is the real reason that causes irrecoverable damage on the Kaiser effect of acoustic emission in cyclic loading. The Kaiser effect reflects the damaged state in rocks rather than the previous stress imposed on it. Applications for using the Kaiser effect to estimate geostress were discussed here. It is shown that the commonly used uniaxial loading method for estimating geostress is not in accor- dance with the theoretical and experimental results. The analysis is of importance to use the Kaiser effect correctly for estimating geostress or in other fields. 2008 University of Science and Technology Beijing. All rights reserved.展开更多
Radiological properties, such as the linear attenuation coefficient(μ), mass attenuation coefficient(μ/ρ), half-value layer(HVL), tenth-value layer(TVL), mean free path(MFP), and effective atomic number(Z_(eff)), o...Radiological properties, such as the linear attenuation coefficient(μ), mass attenuation coefficient(μ/ρ), half-value layer(HVL), tenth-value layer(TVL), mean free path(MFP), and effective atomic number(Z_(eff)), of 304 L stainless steels have been investigated with respect to photon interactions to determine the influence of current intensity at different gamma-ray energies.^(137)Cs and ^(60)Co radioactive point sources were used to irradiate 304 L stainless steels joined at 45–70-A weld currents for the transmission of the gamma rays at photon energies of661.0, 1173.2, and 1332.5 ke V. The μ, μ/ρ, HVL, TVL,MFP, and Z_(eff) of the steels were measured at the mentioned energies, and theoretical values for pure 304 L stainless steel were calculated for comparison. The minimum differences(%) in Z_(eff) between pure steel and steel joined at a weld current of 60 A were observed for relevant photon energies; the minimum difference between the theoretical value for pure 304 L and the experimental value for joined steel was 4.76%, and that between the experimental value for pure 304 L and the experimental value for joined steel was 2.60% at 1332.5 ke V. Moreover, the MFPs of the joined steels were compared with that of pure 304 L, and steel joined at 60 A, which had the minimum MFP, was compared with some radiation-shielding concretes in terms of MFP at the same gamma-ray energies.展开更多
Finding causality merely from observed data is a fundamental problem in science. The most basic form of this causal problem is to determine whether X leads to Y or Y leads to X in the case of joint observation of two ...Finding causality merely from observed data is a fundamental problem in science. The most basic form of this causal problem is to determine whether X leads to Y or Y leads to X in the case of joint observation of two variables X, Y. In statistics, path analysis is used to describe the direct dependence between a set of variables. But in fact, we usually do not know the causal order between variables. However, ignoring the direction of the causal path will prevent researchers from analyzing or using causal models. In this study, we propose a method for estimating causality based on observed data. First, observed variables are cleaned and valid variables are retained. Then, a direct linear non-Gaussian acyclic graph models(DirectLiNGAM) estimates the causal order K between variables. The third step is to estimate the adjacency matrix B of the causal relationship based on K. Next, since B is not convenient for model interpretation, we use adaptive lasso to prune the causal path and variables. Further, a causal path graph and a recursive model are established. Finally, we test and debug the recursive model, obtain a causal model with good fit, and estimate the direct, indirect and total effects between causal variables. This paper overcomes the randomness assigning causal order to variables. This study is different from the researcher’s understanding of his own model by generating some form of simulation data. The simplest and relatively unsmooth statistical learning method used in this study has obvious advantages in the field of interpretable machine learning.展开更多
Undergraduate student’s satisfaction is fundamental to creating and implementing successful higher education.The present study sought to identify the factors and analyses impact on satisfaction and service quality.Th...Undergraduate student’s satisfaction is fundamental to creating and implementing successful higher education.The present study sought to identify the factors and analyses impact on satisfaction and service quality.The research was carried out in Chinese higher education institution,with a sample of 1660 students.Based on the higher education satisfaction questionnaire,the“optimal path”model of problem improvement was constructed by applying the“structural equation model”,satisfaction and importance matrix diagram,improvement effect size and other tools.Eight major areas of three-dimensional improvement of“satisfaction,importance,and improvement effect”were formed.Identify the issues that students have urgent demands,high importance,and strong improvement effects.Scientifically analyze the main attention focus of each subgroup of students.Concentrate superior resources and strengths,formulate targeted measures and make key breakthroughs based on“light”,“heavy”,“slow”,“urgent”and“classified”.Provide suggestions for improving student’s satisfaction and promoting the development of high-quality connotative and characteristic development in higher education.展开更多
基金support given by the National Natural Science Foundation of China(No.51275202)
文摘The flexible rolling process(FRP) is a novel three-dimensional(3 D) forming process that combines the multipoint and traditional rolling forming. The principle of FRP is based on thickness thinning, so the deformation path significantly impacts the forming effect. In this study, the multistep forming process with different deformation paths was introduced to improve the forming effect of FRP. For instance, with the convex surface part, three finite element models of multistep FRP(MSFRP) were established. The corresponding numerical simulations and forming experiments performed among different deformation paths showed the surface part with a longer effective forming region was obtained and the forming regions with more steps in MSFRP were smoother. Thus, the sheet-metal utilization rate was greatly improved. Moreover, the MSFRP can improve the longitudinal bending effect dramatically and thereby endowing the forming part with a better forming effect. Therefore, MSFRP is a prospective method for broad applications.
基金Project Supported by National Natural Science Foundation of China（50237010）.
文摘This paper investigates the development,the breakdown process,and the discharge path selection of the lightning discharges in two-phase mixtures(TPMs).13 kinds of solid-gas mixtures and 3 kinds of liquid-gas mixtures are employed to study effect of two phase mixtures on the selection of the discharge path under lightning impulses.Grain size effects are shown upon these experimental results.When the diameter of solid or liquid grains is less than about 10 μm,the discharge path does not select TPM but air.And the discharge path selects TPM when the diameter is greater than about 100 μm.And when the diameter is between about 10 μm and 100 μm,the discharge path selects TPM under negative lightning impulses,but it has a greater selection of air than TPMs under positive lightning impulses.Volume fraction and permittivity of solid/liquid can also influence the selection of the discharge path.
文摘In the paper presented, 99 single seed descent barley lines as well as their parental forms Roland and Apex were studied. The grain weight components and their interrelations were analyzed using simple coefficients of correlation. The direct and indirect effects of such components on grain weight per plant and 1 000-grain weight were estimated using path analysis. In the 2006 and 2007, the spike length and number of spikelets per spike were the determinants of grain weight. Genetic parameters as additive and epistasis effects were estimated for all studied traits. The results indicate the importance of both additive and epistasis gene effects of number of spikes per plant, grain weight per spike, grain number per plant and grain weight per plant in this study.
文摘At present,higher education in China has entered the stage of popularization,and the"connotative development of higher education"has become the inevitable choice for the development of colleges and universities in China.In the process of"connotative development"in higher education,we must realize the importance of discipline construction and optimize discipline layout and specialty construction,improve the quality of personnel trained by colleges and universities in order to satisfy the needs of social and economic development.On this basis,colleges and universities should,according to the market demand for talents,reform and innovate the talent training mode,continuously strengthen the construction of teaching staff,improve the quality of classroom teaching,effectively improve students'social practice capability,improve the quality of talent training,and take a connotative development path through school-enterprise cooperation and integration of production and teaching.
基金Tabs paper is financially suPPorted by the NationalNatural Science Foundation of China (No. 59975021).
文摘The influence of loading path on tube hydroforming process is discussed in this paper with finiteelement simulation. Four different loading paths are utilized in simulating the forming process of square tubular component with hydroforming and the result of different loading path is presented. Among the result. the thickness distribution of bilinear loading path is the most uniform one. It shows that the increase of punch displacement in the stage of high pressure is beneficial to the forming of component for optimized Stress condition.
基金This work was jointly supported by the 973 Project(Grant No.2005CB321703)the National Natural Science Foundation of China(Grant No.40221503)the Chinese Academy of Sciences International Partnership Creative Group entitled"The Climate System Model Development and Application Studies".
文摘This paper documents a study to examine the sensitivity to cloud droplet effective radius and liquid water path and the alleviation the energy imbalance at the top of the atmosphere and at the surface in the latest version of the Grid-point Atmospheric Model of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG）, Institute of Atmospheric Physics （IAP） （GAMIL1.1.0）. Considerable negative biases in all flux components, and thus an energy imbalance, are found in GAMIL1.1.0. In order to alleviate the energy imbalance, two modifications, namely an increase in cloud droplet effective radius and a decrease in cloud liquid water path, have been made to the cloud properties used in GAMIL. With the increased cloud droplet effective radius, the single scattering albedo of clouds is reduced, and thus the reflection of solar radiation into space by clouds is reduced and the net solar radiation flux at the top of the atmosphere is increased. With the reduced cloud optical depth, the net surface shortwave radiation flux is increased, causing a net warming over the land surface. This results in an increase in both sensible and latent heat fluxes over the land regions, which is largely balanced by the increased terrestrial radiation fluxes. Consequently, the energy balance at the top of atmosphere and at the surface is achieved with energy flux components consistent with available satellite observations.
基金Supported by the Project of Tianjin Philosophy and Social Science Research(2-329)
文摘The problem of insufficient agricultural input has been restricting China's agricultural development. When the expansion of the use of capital has become a bottleneck restricting the agricultural development,the effective use of agricultural input resources will become an important way to increase agricultural input. Through building the value chain of interactive development between urban agriculture and other industries,it is expected to promote the reasonable allocation of resources,realize the conservation of resources and increase the efficiency of resource utilization,and promote the urban agricultural input to become an effective input. In this way,it can realize the transformation of agricultural development and the innovation of financing method of urban agriculture.
文摘Using the path integral formalism, the fine structure and dynamics effects are taken into account for the broadening of spectral lines in a plasma. A compact expression of the dipolar autocorrelation function for an emitter in the plasma is derived for Lyman alpha lines with fine structure. The expression of the dipolar autocorrelation function takes into account the dynamics effects, which are represented by the time microfield autocorrelation function.
基金National Natural Science Foundation of China,No.42122007,No.41930646Guangdong Academy of Sciences Project of Science and Technology Development,No.2019GDASYL-0104004。
文摘This paper examines the rise of informal economies in China,a hidden driving force overlooked in studies on China’s urbanization.Estimating the size of informal economies using the multiple indicators multiple causes model,the paper employs mathematical models to examine the driving effect of informal economies on urbanization and to reveal the paths by which such effect works.The results were as follows.(1)In 2018,the size of the informal economy in China accounted for 23.5%of GDP with an output value of 21.16 trillion yuan.(2)The informal economy had a driving effect on China’s urbanization,and every 1-percentagepoint increase in its share of the GDP led to an increase of 0.291 percentage points in the urbanization rate.(3)The informal economy’s effect on urbanization showed regional differences,decreasing in size from the eastern to the central to the western regions.(4)The informal economy drives urbanization through four paths-by promoting foreign direct investment(FDI),fixed asset investment(FAI),social consumption(SC),and secondary sector employment(SSE).Their effect sizes are ranked in descending order as follows:FDI>FAI>SC>SSE.This paper contributes to theories on urbanization dynamics and process in China by highlighting the role of the informal economy as a hidden economic power lurking in the city.
基金the National Natural Science Foundation of China(No.50474017).
文摘The Kaiser effect is formally described as the absence of detectable acoustic emission （AE） events until the load imposed on the material exceeds the previous applied level and is usually used to estimate geostress. By focusing on the heterogeneity of rock material, the mechanism of the Kaiser effect under cyclic loading is analyzed based on statistic damage mechanics. Two groups of granite specimens have been cyclically loaded with two different loading paths to verify the theoretical results. The heterogeneity of rock is the real reason that causes irrecoverable damage on the Kaiser effect of acoustic emission in cyclic loading. The Kaiser effect reflects the damaged state in rocks rather than the previous stress imposed on it. Applications for using the Kaiser effect to estimate geostress were discussed here. It is shown that the commonly used uniaxial loading method for estimating geostress is not in accor- dance with the theoretical and experimental results. The analysis is of importance to use the Kaiser effect correctly for estimating geostress or in other fields. 2008 University of Science and Technology Beijing. All rights reserved.
基金supported by the Yalova University Scientific Research Foundation(No.2013-062)
文摘Radiological properties, such as the linear attenuation coefficient(μ), mass attenuation coefficient(μ/ρ), half-value layer(HVL), tenth-value layer(TVL), mean free path(MFP), and effective atomic number(Z_(eff)), of 304 L stainless steels have been investigated with respect to photon interactions to determine the influence of current intensity at different gamma-ray energies.^(137)Cs and ^(60)Co radioactive point sources were used to irradiate 304 L stainless steels joined at 45–70-A weld currents for the transmission of the gamma rays at photon energies of661.0, 1173.2, and 1332.5 ke V. The μ, μ/ρ, HVL, TVL,MFP, and Z_(eff) of the steels were measured at the mentioned energies, and theoretical values for pure 304 L stainless steel were calculated for comparison. The minimum differences(%) in Z_(eff) between pure steel and steel joined at a weld current of 60 A were observed for relevant photon energies; the minimum difference between the theoretical value for pure 304 L and the experimental value for joined steel was 4.76%, and that between the experimental value for pure 304 L and the experimental value for joined steel was 2.60% at 1332.5 ke V. Moreover, the MFPs of the joined steels were compared with that of pure 304 L, and steel joined at 60 A, which had the minimum MFP, was compared with some radiation-shielding concretes in terms of MFP at the same gamma-ray energies.
基金Supported by the National Natural Science Foundation of China(61573266)
文摘Finding causality merely from observed data is a fundamental problem in science. The most basic form of this causal problem is to determine whether X leads to Y or Y leads to X in the case of joint observation of two variables X, Y. In statistics, path analysis is used to describe the direct dependence between a set of variables. But in fact, we usually do not know the causal order between variables. However, ignoring the direction of the causal path will prevent researchers from analyzing or using causal models. In this study, we propose a method for estimating causality based on observed data. First, observed variables are cleaned and valid variables are retained. Then, a direct linear non-Gaussian acyclic graph models(DirectLiNGAM) estimates the causal order K between variables. The third step is to estimate the adjacency matrix B of the causal relationship based on K. Next, since B is not convenient for model interpretation, we use adaptive lasso to prune the causal path and variables. Further, a causal path graph and a recursive model are established. Finally, we test and debug the recursive model, obtain a causal model with good fit, and estimate the direct, indirect and total effects between causal variables. This paper overcomes the randomness assigning causal order to variables. This study is different from the researcher’s understanding of his own model by generating some form of simulation data. The simplest and relatively unsmooth statistical learning method used in this study has obvious advantages in the field of interpretable machine learning.
基金supported by the Chongqing Education Science Planning funds,and the project is 2021-GX-114.
文摘Undergraduate student’s satisfaction is fundamental to creating and implementing successful higher education.The present study sought to identify the factors and analyses impact on satisfaction and service quality.The research was carried out in Chinese higher education institution,with a sample of 1660 students.Based on the higher education satisfaction questionnaire,the“optimal path”model of problem improvement was constructed by applying the“structural equation model”,satisfaction and importance matrix diagram,improvement effect size and other tools.Eight major areas of three-dimensional improvement of“satisfaction,importance,and improvement effect”were formed.Identify the issues that students have urgent demands,high importance,and strong improvement effects.Scientifically analyze the main attention focus of each subgroup of students.Concentrate superior resources and strengths,formulate targeted measures and make key breakthroughs based on“light”,“heavy”,“slow”,“urgent”and“classified”.Provide suggestions for improving student’s satisfaction and promoting the development of high-quality connotative and characteristic development in higher education.
