This study measured the level of innovation achievement protection and the degree of internal structural upgrading of the productive service industry in 28 provinces of China from 2000 to 2022.Exploratory spatial anal...This study measured the level of innovation achievement protection and the degree of internal structural upgrading of the productive service industry in 28 provinces of China from 2000 to 2022.Exploratory spatial analysis methods were used to test the spatial correlation between the two variables,and the spatial impact of innovation achievement protection on the optimization of the internal structure of the productive service industry was examined at the national and sectoral levels.The results showed three main aspects of this system.(1)The agglomeration level of innovation achievement protection and internal structure optimization of the productive service industry between regions in China continued to increase during the sample period,and there was a clear similarity and synchronicity in the spatial evolution of the two variables.(2)The overall improvement in the protection level of innovative achievements is conducive to promoting the internal structural upgrading of China’s productive service industry.However,there are significant differences in the degree to which the protection of innovative achievements affects the internal structural upgrading of the productive service industry in the four major regions of the East,Central,Northeast,and West.The protection of innovative achievements in the East and Central regions significantly promotes the internal structural optimization of the productive service industry,while this effect is not significant in the western and northeastern regions.(3)The results of the robustness test indicate that the impact of internal structural upgrading of the productive service industry in the previous year on the level of innovation achievement protection is not significant.The interference from abnormal values of the internal structural upgrading of the productive service industry in various regions and the influence of municipalities directly under the central government on the regression results are not significant.After replacing the main variable,the coefficient of the innovation achievement protection level remained significantly positive.The conclusions of this study supplement and improve the theory of innovation achievement protection and industrial transformation and upgrading,providing decision-making support for improving the level of innovation achievement protection and promoting the internal structural upgrading of the productive service industries in China.展开更多
The Weihe River Basin has a significant number of tributaries and a delicate ecological environment.Understanding the spatial and temporal evolution and determinants of landscape ecological risk in the Weihe River Bas...The Weihe River Basin has a significant number of tributaries and a delicate ecological environment.Understanding the spatial and temporal evolution and determinants of landscape ecological risk in the Weihe River Basin(WRB)can improve the scientific protection and development of its watershed ecosystems.This study is based on land use statistics from the WRB for a 30-year period represented by 1990,2000,2010,and 2020.An initial model for the assessment of landscaping ecological hazards was created using the software that was also used to generate the landscape ecological risk index,such as ArcGIS 10.4 and Fragstats 4.2-64.Next,the spatial and temporal evolution of landscape ecological risk in the vicinity of the study area was characterized by the trajectory of the center of gravity migration and the spatial autocorrelation of GeoDa.Finally,Geodetector was used to analyze ecological risk drivers in the landscapes.According to the findings,the high-risk and relatively high-risk regions are steadily expanding,while the low-risk and relatively low-risk areas dominate the ecological risk landscape in the WRB.Within the Weihe River Basin,Xianyang and Xi'an are the areas to which the high-risk centers of gravity are migrating.Positive spatial correlations were found between the landscape ecological hazards in the study area,most prominently in the form of high-high and low-low aggregations.The primary drivers are the interplay between the GDP component,temperature,and elevation as a single factor.展开更多
Pitot probes enable a simple and convenient way of measuring mean velocity in air flow. The contrastive numerical simulation between free supersonic airflow and pitot tube at different positions in supersonic air flow...Pitot probes enable a simple and convenient way of measuring mean velocity in air flow. The contrastive numerical simulation between free supersonic airflow and pitot tube at different positions in supersonic air flow was performed using Navier-Stokes equations, the ENN scheme with time-dependent boundary conditions （TDBC） and the Spalart-Allmaras turbulence model. The physical experimental results including pitot pressure and shadowgraph are also presented. Numerical results coincide with the experimental data. The flow characteristics of the pitot probe on the supersonic flow structure show that the measure- ment gives actually the total pressure behind the detached shock wave by using the pitot probe to measure the total pressure. The measurement result of the distribution of the total pressure can still represent the real free jet flow. The similar features of the intersection and reflection of shock waves can be identified. The difference between the measurement results and the actual ones is smaller than 10%. When the pitot probe is used to measure the region of L=0-4D, the measurement is smaller than the real one due to the increase of the shock wave strength. The difference becomes larger where the waves intersect. If the pitot probe is put at L=SD-10D, where the flow changes from supersonic to subsonic, the addition of the pitot probe turns the original supersonic flow region subsonic and causes bigger measurement errors.展开更多
基金The National Social Science Foundation of China(23BJL091)。
文摘This study measured the level of innovation achievement protection and the degree of internal structural upgrading of the productive service industry in 28 provinces of China from 2000 to 2022.Exploratory spatial analysis methods were used to test the spatial correlation between the two variables,and the spatial impact of innovation achievement protection on the optimization of the internal structure of the productive service industry was examined at the national and sectoral levels.The results showed three main aspects of this system.(1)The agglomeration level of innovation achievement protection and internal structure optimization of the productive service industry between regions in China continued to increase during the sample period,and there was a clear similarity and synchronicity in the spatial evolution of the two variables.(2)The overall improvement in the protection level of innovative achievements is conducive to promoting the internal structural upgrading of China’s productive service industry.However,there are significant differences in the degree to which the protection of innovative achievements affects the internal structural upgrading of the productive service industry in the four major regions of the East,Central,Northeast,and West.The protection of innovative achievements in the East and Central regions significantly promotes the internal structural optimization of the productive service industry,while this effect is not significant in the western and northeastern regions.(3)The results of the robustness test indicate that the impact of internal structural upgrading of the productive service industry in the previous year on the level of innovation achievement protection is not significant.The interference from abnormal values of the internal structural upgrading of the productive service industry in various regions and the influence of municipalities directly under the central government on the regression results are not significant.After replacing the main variable,the coefficient of the innovation achievement protection level remained significantly positive.The conclusions of this study supplement and improve the theory of innovation achievement protection and industrial transformation and upgrading,providing decision-making support for improving the level of innovation achievement protection and promoting the internal structural upgrading of the productive service industries in China.
基金The Soft Science Research Project of Henan Provincial Science and Technology Department(212400410023)The General Project of Henan University Humanities and Social Science Research(2021-ZZJH-159).
文摘The Weihe River Basin has a significant number of tributaries and a delicate ecological environment.Understanding the spatial and temporal evolution and determinants of landscape ecological risk in the Weihe River Basin(WRB)can improve the scientific protection and development of its watershed ecosystems.This study is based on land use statistics from the WRB for a 30-year period represented by 1990,2000,2010,and 2020.An initial model for the assessment of landscaping ecological hazards was created using the software that was also used to generate the landscape ecological risk index,such as ArcGIS 10.4 and Fragstats 4.2-64.Next,the spatial and temporal evolution of landscape ecological risk in the vicinity of the study area was characterized by the trajectory of the center of gravity migration and the spatial autocorrelation of GeoDa.Finally,Geodetector was used to analyze ecological risk drivers in the landscapes.According to the findings,the high-risk and relatively high-risk regions are steadily expanding,while the low-risk and relatively low-risk areas dominate the ecological risk landscape in the WRB.Within the Weihe River Basin,Xianyang and Xi'an are the areas to which the high-risk centers of gravity are migrating.Positive spatial correlations were found between the landscape ecological hazards in the study area,most prominently in the form of high-high and low-low aggregations.The primary drivers are the interplay between the GDP component,temperature,and elevation as a single factor.
基金supported by the National Natural Science Foundation of China (Grant No. 30970822)
文摘Pitot probes enable a simple and convenient way of measuring mean velocity in air flow. The contrastive numerical simulation between free supersonic airflow and pitot tube at different positions in supersonic air flow was performed using Navier-Stokes equations, the ENN scheme with time-dependent boundary conditions （TDBC） and the Spalart-Allmaras turbulence model. The physical experimental results including pitot pressure and shadowgraph are also presented. Numerical results coincide with the experimental data. The flow characteristics of the pitot probe on the supersonic flow structure show that the measure- ment gives actually the total pressure behind the detached shock wave by using the pitot probe to measure the total pressure. The measurement result of the distribution of the total pressure can still represent the real free jet flow. The similar features of the intersection and reflection of shock waves can be identified. The difference between the measurement results and the actual ones is smaller than 10%. When the pitot probe is used to measure the region of L=0-4D, the measurement is smaller than the real one due to the increase of the shock wave strength. The difference becomes larger where the waves intersect. If the pitot probe is put at L=SD-10D, where the flow changes from supersonic to subsonic, the addition of the pitot probe turns the original supersonic flow region subsonic and causes bigger measurement errors.
