Photothermal Fischer-Tropsch synthesis(FTS)has been extensively studied,but few reports were focused on systematically exploring the influence of support on catalytic performance.Herein,a series of Fe5C2-based catalys...Photothermal Fischer-Tropsch synthesis(FTS)has been extensively studied,but few reports were focused on systematically exploring the influence of support on catalytic performance.Herein,a series of Fe5C2-based catalysts with different supports was fabricated via a one-step wet-chemical method for photothermal conversion of syngas to lower olefins.Under light irradiation,the optimized FesC2/a-Al2O3 catalyst demonstrated remarkable photothermal FTS activity,delivering selectivity to lower olefins of 50.3%with a CO conversion rate of 52.5%.Characterization studies using X-ray diffraction and Mossbauer spectroscopy analysis revealed that the active catalyst mainly contained FesC2 nanoparticles on a-AbO3 support.It was found that the weak interaction between active phase and a-AhO3 could promote the formation of FesC2,which contributed to the high selectivity to lower olefins.展开更多
Given the large volume of video content and the diversity of user attention, it is of great importance to understand the characteristics of online video popularity for technological, economic and social reasons. In th...Given the large volume of video content and the diversity of user attention, it is of great importance to understand the characteristics of online video popularity for technological, economic and social reasons. In this paper, based on the data collected from a leading online video service provider in China, namely Youku, the dynamics of online video popularity are analyzed in-depth from four key aspects: overall popularity distribution, individual popularity distribution, popularity evolution pattern and early-future popularity relationship. How the popularity of a set of newly upload videos distributes throughout the observation period is first studied. Then the notion of active days is proposed, and the per-day and per-hour popularity distributions of individual videos are carefully studied. Next, how the popularity of an individual video evolves over time is investigated. The evolution patterns are further defined according to the number and temporal locations of popularity bursts, in order to describe the popularity growth trend. At last, the linear relationship between early video popularity and future video popularity are examined on a log-log scale. The relationship is found to be largely impacted by the popularity evolution patterns. Therefore, the specialized models are proposed to describe the correlation according to the popularity evolution patterns. Experiment results show that specialized models can better fit the correlation than a general model. Above all, the analysis results in our work can provide direct help in practical for the interested parties of online video service such as service providers, online advisers, and network operators.展开更多
基金Supported by the National Natural Science Foundation of China(No.21972052)the Financial Support from the“izi Scholar”Program of Central China Normal University,China.
文摘Photothermal Fischer-Tropsch synthesis(FTS)has been extensively studied,but few reports were focused on systematically exploring the influence of support on catalytic performance.Herein,a series of Fe5C2-based catalysts with different supports was fabricated via a one-step wet-chemical method for photothermal conversion of syngas to lower olefins.Under light irradiation,the optimized FesC2/a-Al2O3 catalyst demonstrated remarkable photothermal FTS activity,delivering selectivity to lower olefins of 50.3%with a CO conversion rate of 52.5%.Characterization studies using X-ray diffraction and Mossbauer spectroscopy analysis revealed that the active catalyst mainly contained FesC2 nanoparticles on a-AbO3 support.It was found that the weak interaction between active phase and a-AhO3 could promote the formation of FesC2,which contributed to the high selectivity to lower olefins.
基金supported by the Video Super-Resolution Reconstruction Project (20130005110017)
文摘Given the large volume of video content and the diversity of user attention, it is of great importance to understand the characteristics of online video popularity for technological, economic and social reasons. In this paper, based on the data collected from a leading online video service provider in China, namely Youku, the dynamics of online video popularity are analyzed in-depth from four key aspects: overall popularity distribution, individual popularity distribution, popularity evolution pattern and early-future popularity relationship. How the popularity of a set of newly upload videos distributes throughout the observation period is first studied. Then the notion of active days is proposed, and the per-day and per-hour popularity distributions of individual videos are carefully studied. Next, how the popularity of an individual video evolves over time is investigated. The evolution patterns are further defined according to the number and temporal locations of popularity bursts, in order to describe the popularity growth trend. At last, the linear relationship between early video popularity and future video popularity are examined on a log-log scale. The relationship is found to be largely impacted by the popularity evolution patterns. Therefore, the specialized models are proposed to describe the correlation according to the popularity evolution patterns. Experiment results show that specialized models can better fit the correlation than a general model. Above all, the analysis results in our work can provide direct help in practical for the interested parties of online video service such as service providers, online advisers, and network operators.
