All-fiber coherent beam combiners based on the self-imaging effect can achieve a near-perfect single laser beam,which can provide a promising way to overcome the power limitation of a single-fiber laser.One of the key...All-fiber coherent beam combiners based on the self-imaging effect can achieve a near-perfect single laser beam,which can provide a promising way to overcome the power limitation of a single-fiber laser.One of the key points is combining efficiency,which is determined by various mismatches during fabrication.A theoretical model has been built,and the mismatch error is analyzed numerically for the first time.The mismatch errors have been numerically studied with the beam quality and combining efficiency being chosen as the evaluation criteria.The tolerance of each mismatch error for causing 1%loss is calculated to guide the design of the beam combiners.The simulation results are consistent with the experimental results,which show that the mismatch error of the square-core fiber is the main cause of the efficiency loss.The results can provide useful guidance for the fabrication of all-fiber coherent beam combiners.展开更多
Identification of the spatial mismatch between land use functions(LUFs)and land use efficiencies(LUEs)is essential to regional land use policies.However,previous studies about LUF-LUE mismatch and its driving factors ...Identification of the spatial mismatch between land use functions(LUFs)and land use efficiencies(LUEs)is essential to regional land use policies.However,previous studies about LUF-LUE mismatch and its driving factors have been insufficient.In this study,we explored the spatiotemporal mismatch of LUFs and LUEs and their influencing factors from 2000 to 2018 in the Middle Reaches of the Yangtze River(MRYR).Specifically,we used Spearman correlation analysis to reveal the trade-off relationship between LUFs and LUEs and determine the direction of the influencing factors on the LUF-LUE mismatch,adopted spatial mismatch analysis to measure the imbalance between LUFs and LUEs,and used the geographical detector model to analyze the factors influencing this spatial mismatch.The results showed that production function(PDF),living function(LVF),ecological function(ELF),agricultural production efficiency(APE),urban construction efficiency(UCE),and ecological services efficiency(ESE)all displayed significant spatial heterogeneity.The high trade-off areas were widely distributed and long-lasting in agricultural space and urban space,while gradually decreasing in ecological space.Wuhan and Changsha showed high spatial mismatch coefficients in urban space,but low spatial mismatch coefficients in agricultural space.Hunan generally presented high spatial mismatch coefficients in ecological space.Furthermore,the interaction of the proportion of cultivated area and transportation accessibility exacerbated the mismatch in agricultural space.The interaction effects of capital investment and technology innovation with other factors have the most intense impact on the mismatch in urban space.The internal factor for cultivated area interacts with other external factors to drastically affect ecological spatial mismatch.展开更多
This paper attempts at an in-depth exploration of lexical mismatching, a pattern of vocabulary errors. In this paper, errors per se were collected from 107 writing samples of Chinese college students, and then investi...This paper attempts at an in-depth exploration of lexical mismatching, a pattern of vocabulary errors. In this paper, errors per se were collected from 107 writing samples of Chinese college students, and then investigated from a variety of linguistic perspectives. Traditional theoretical approaches, i.e. CA and EA, are incorporated in the source analysis for a more comprehensive interpretation. Hopefully, the findings of the study will shed lights on lexical instruction and acquisition in the field of SLA.展开更多
文摘All-fiber coherent beam combiners based on the self-imaging effect can achieve a near-perfect single laser beam,which can provide a promising way to overcome the power limitation of a single-fiber laser.One of the key points is combining efficiency,which is determined by various mismatches during fabrication.A theoretical model has been built,and the mismatch error is analyzed numerically for the first time.The mismatch errors have been numerically studied with the beam quality and combining efficiency being chosen as the evaluation criteria.The tolerance of each mismatch error for causing 1%loss is calculated to guide the design of the beam combiners.The simulation results are consistent with the experimental results,which show that the mismatch error of the square-core fiber is the main cause of the efficiency loss.The results can provide useful guidance for the fabrication of all-fiber coherent beam combiners.
基金Key Project of the National Social Science Foundation of China,No.23AZD058National Natural Science Foundation of China,No.72004209。
文摘Identification of the spatial mismatch between land use functions(LUFs)and land use efficiencies(LUEs)is essential to regional land use policies.However,previous studies about LUF-LUE mismatch and its driving factors have been insufficient.In this study,we explored the spatiotemporal mismatch of LUFs and LUEs and their influencing factors from 2000 to 2018 in the Middle Reaches of the Yangtze River(MRYR).Specifically,we used Spearman correlation analysis to reveal the trade-off relationship between LUFs and LUEs and determine the direction of the influencing factors on the LUF-LUE mismatch,adopted spatial mismatch analysis to measure the imbalance between LUFs and LUEs,and used the geographical detector model to analyze the factors influencing this spatial mismatch.The results showed that production function(PDF),living function(LVF),ecological function(ELF),agricultural production efficiency(APE),urban construction efficiency(UCE),and ecological services efficiency(ESE)all displayed significant spatial heterogeneity.The high trade-off areas were widely distributed and long-lasting in agricultural space and urban space,while gradually decreasing in ecological space.Wuhan and Changsha showed high spatial mismatch coefficients in urban space,but low spatial mismatch coefficients in agricultural space.Hunan generally presented high spatial mismatch coefficients in ecological space.Furthermore,the interaction of the proportion of cultivated area and transportation accessibility exacerbated the mismatch in agricultural space.The interaction effects of capital investment and technology innovation with other factors have the most intense impact on the mismatch in urban space.The internal factor for cultivated area interacts with other external factors to drastically affect ecological spatial mismatch.
文摘This paper attempts at an in-depth exploration of lexical mismatching, a pattern of vocabulary errors. In this paper, errors per se were collected from 107 writing samples of Chinese college students, and then investigated from a variety of linguistic perspectives. Traditional theoretical approaches, i.e. CA and EA, are incorporated in the source analysis for a more comprehensive interpretation. Hopefully, the findings of the study will shed lights on lexical instruction and acquisition in the field of SLA.
