A distributed feedback laser with a wavelength of 2.8μm was used to measure the species produced by water vapor glow discharge.Only the absorption spectra of OH radicals and transient H2O molecules were observed usin...A distributed feedback laser with a wavelength of 2.8μm was used to measure the species produced by water vapor glow discharge.Only the absorption spectra of OH radicals and transient H2O molecules were observed using concentration modulation(CM)spectroscopy.The intensities and orientations of the absorption peaks change with the demodulation phase,but the direction of one absorption peak of H2O is always opposite to the other peaks.The different spectral orientations of OH and H2O reflect the increase or the decrease of the number of particles in the energy levels.If more transient species can be detected in the discharge process,the dynamics of excitation,ionization,and decomposition of H2O can be better studied.This study shows that the demodulation phase relationship of CM spectrum can be used to study the population change of molecular energy levels.展开更多
China has entered a new stage of high-quality urbanization.Therefore,it is critical to grasp the latest population distribution and dynamics.Using mean-variance grading,Moran’s index,and the Theil index,this study co...China has entered a new stage of high-quality urbanization.Therefore,it is critical to grasp the latest population distribution and dynamics.Using mean-variance grading,Moran’s index,and the Theil index,this study compared the differences in population changes between 2010–2020 and 2000–2010 at the prefecture-level city scale based on census data to analyze the new trends in population evolution.We found that:(1)New growth poles of the population are inland provincial capitals,forming rapid-growing zones together with coastal urban agglomerations.Population growth in over 60%of the cities in the northern coastal urban agglomeration has slowed.(2)The scope of population loss in inland areas is constantly expanding.In the northeastern part of China,92.7%of the cities have lost population,making this a typical population loss area.(3)Population shrinkage in the northeastern region and growth in the Pearl River Delta urban agglomeration show diffusion characteristics,while population patterns around the provincial capital are in a polarized stage.(4)The Theil index of population distribution increased,with 83.91%of differences coming from between groups,indicating that the gap between cities of different sizes has further expanded.This study provides scientific support for the coordinated promotion of nearby and remote urbanization.展开更多
基金the National Natural Science Foundation of China(No.61625501,No.61427816)the Open Fund of the State Key Laboratory of High Field Laser Physics(SIOM)the Open Fund of the State Key Laboratory of Precision Spectroscopy。
文摘A distributed feedback laser with a wavelength of 2.8μm was used to measure the species produced by water vapor glow discharge.Only the absorption spectra of OH radicals and transient H2O molecules were observed using concentration modulation(CM)spectroscopy.The intensities and orientations of the absorption peaks change with the demodulation phase,but the direction of one absorption peak of H2O is always opposite to the other peaks.The different spectral orientations of OH and H2O reflect the increase or the decrease of the number of particles in the energy levels.If more transient species can be detected in the discharge process,the dynamics of excitation,ionization,and decomposition of H2O can be better studied.This study shows that the demodulation phase relationship of CM spectrum can be used to study the population change of molecular energy levels.
基金National Natural Science Foundation of China,No.42121001,No.42171204,No.41822104。
文摘China has entered a new stage of high-quality urbanization.Therefore,it is critical to grasp the latest population distribution and dynamics.Using mean-variance grading,Moran’s index,and the Theil index,this study compared the differences in population changes between 2010–2020 and 2000–2010 at the prefecture-level city scale based on census data to analyze the new trends in population evolution.We found that:(1)New growth poles of the population are inland provincial capitals,forming rapid-growing zones together with coastal urban agglomerations.Population growth in over 60%of the cities in the northern coastal urban agglomeration has slowed.(2)The scope of population loss in inland areas is constantly expanding.In the northeastern part of China,92.7%of the cities have lost population,making this a typical population loss area.(3)Population shrinkage in the northeastern region and growth in the Pearl River Delta urban agglomeration show diffusion characteristics,while population patterns around the provincial capital are in a polarized stage.(4)The Theil index of population distribution increased,with 83.91%of differences coming from between groups,indicating that the gap between cities of different sizes has further expanded.This study provides scientific support for the coordinated promotion of nearby and remote urbanization.
