Phenolics,as the main bioactive compounds in tea,have been suggested to have potential in the prevention of various human diseases.However,little is known about phenolics and their bioactivity in Zhangping Narcissue t...Phenolics,as the main bioactive compounds in tea,have been suggested to have potential in the prevention of various human diseases.However,little is known about phenolics and their bioactivity in Zhangping Narcissue tea cake which is considered the most special kind of oolong tea.To unveil its bioactivity,three phenolic-enriched extracts were obtained from Zhangping Narcissue tea cake using ethyl acetate,n-butanol,and water.Their main chemical compositions and in vitro bioactivity were analyzed by high-performance liquid chromatography(HPLC)and ultraperformance liquid chromatography-mass spectrometry(UPLC-MS).The ethyl acetate fraction(ZEF)consisted of higher content of phenolics,flavonoids,procyanidins,and catechin monomers(including epigallocatechin gallate(EGCG),epicatechin gallate(ECG),and gallocatechin gallate(GCG))than n-butanol fraction(ZBF)and water fraction(ZWF).ZEF exhibited the strongest antioxidant capacity in vitro due to its abundant bioactive compounds.This was validated by Pearson correlation and hierarchical clustering analyses.ZEF also showed a remarkable inhibition on the growth,migration,and invasion of 4T1 murine breast cancer cells.展开更多
Explosive synchronization(ES)is a kind of first-order jump phenomenon that exists in physical and biological systems.In recent years,researchers have focused on ES between single-layer and multi-layer networks.Most re...Explosive synchronization(ES)is a kind of first-order jump phenomenon that exists in physical and biological systems.In recent years,researchers have focused on ES between single-layer and multi-layer networks.Most research on complex networks with delay has focused on single-layer or double-layer networks,multi-layer networks are seldom explored.In this paper,we propose a Kuramoto model of frequency weights in multi-layer complex networks with delay and star connections between layers.Through theoretical analysis and numerical verification,the factors affecting the backward critical coupling strength are analyzed.The results show that the interaction between layers and the average node degree has a direct effect on the backward critical coupling strength of each layer network.The location of the delay,the size of the delay,the number of network layers,the number of nodes,and the network topology are revealed to have no direct impact on the backward critical coupling strength of the network.Delay is introduced to explore the influence of delay and other related parameters on ES.展开更多
Nb-Mo-ZrB2 composites （V（Nb）/V（Mo） = 1） with 15v01% or 30v01% of ZrB2 were fabricated by hot-pressing sintering at 2000~C The phases, microstxucture, and mechamcal properties were then investigated. The composit...Nb-Mo-ZrB2 composites （V（Nb）/V（Mo） = 1） with 15v01% or 30v01% of ZrB2 were fabricated by hot-pressing sintering at 2000~C The phases, microstxucture, and mechamcal properties were then investigated. The composites contain Nb-Mo solid solution （denoted as （Nb, Mo）ss hereafter）, ZrB, MoB, and NbB phases. Compressive strength test results suggest that the strength of Nb-Mo-ZrB2 composites increases with increasing ZrB2 content; Nb-Mo-30vol%ZrB2 had the highest compressive strength （1905.1 MPa）. The improvement in the compressive strength of the Nb-Mo-ZrB2 composites is mainly attributed to the secondary phase strengthening oftke stiffer ZrB phase, sol- id-solution strengthening oftke （Nb, Mo）ss matrix as well as fme-grain strengtkening. The fracture toughness decreases with increasing ZrB2 content. Finally, the fracture modes oftke Nb-Mo-ZrB2 composites axe also discussed in detail.展开更多
It is difficult to solve complete coverage path planning directly in the obstructed area. Therefore, in this paper, we propose a method of complete coverage path planning with improved area division. Firstly, the bous...It is difficult to solve complete coverage path planning directly in the obstructed area. Therefore, in this paper, we propose a method of complete coverage path planning with improved area division. Firstly, the boustrophedon cell decomposition method is used to partition the map into sub-regions. The complete coverage paths within each sub-region are obtained by the Boustrophedon back-and-forth motions, and the order of traversal of the sub-regions is then described as a generalised traveling salesman problem with pickup and delivery based on the relative positions of the vertices of each sub-region. An adaptive large neighbourhood algorithm is proposed to quickly obtain solution results in traversal order. The effectiveness of the improved algorithm on traversal cost reduction is verified in this paper through multiple sets of experiments. .展开更多
Recently, approaches utilizing spatial-temporal features to form Bag-of-Words （BoWs） models have achieved great success due to their simplicity and effectiveness. But they still have difficulties when distinguishing...Recently, approaches utilizing spatial-temporal features to form Bag-of-Words （BoWs） models have achieved great success due to their simplicity and effectiveness. But they still have difficulties when distinguishing between actions with high inter-ambiguity. The main reason is that they describe actions by orderless bag of features, and ignore the spatial and temporal structure information of visual words. In order to improve classification performance, we present a novel approach called sequential Bag-of-Words. It captures temporal sequential structure by segmenting the entire action into sub-actions. Meanwhile, we pay more attention to the distinguishing parts of an action by classifying sub- actions separately, which is then employed to vote for the final result. Extensive experiments are conducted on challenging datasets and real scenes to evaluate our method. Concretely, we compare our results to some state-of-the-art classification approaches and confirm the advantages of our approach to distinguish similar actions. Results show that our approach is robust and outperforms most existing BoWs based classification approaches, especially on complex datasets with interactive activities, cluttered backgrounds and inter-class action ambiguities.展开更多
Indoor multi-tracking is more challenging compared with outdoor tasks due to frequent occlusion, view-truncation, severe scale change and pose variation, which may bring considerable unreliability and ambiguity to tar...Indoor multi-tracking is more challenging compared with outdoor tasks due to frequent occlusion, view-truncation, severe scale change and pose variation, which may bring considerable unreliability and ambiguity to target representation and data association. So discriminative and reliable target representation is vital for accurate data association in multi-tracking. Pervious works always combine bunch of features to increase the discriminative power, but this is prone to error accumulation and unnecessary computational cost, which may increase ambiguity on the contrary. Moreover, reliability of a same feature in different scenes may vary a lot, especially for currently widespread network cameras, which are settled in various and complex indoor scenes, previous fixed feature selection schemes cannot meet general requirements. To properly handle these problems, first, we propose a scene-adaptive hierarchical data association scheme, which adaptively selects features with higher reliability on target representation in the applied scene, and gradually combines features to the minimum requirement of discriminating ambiguous targets; second, a novel depth-invariant part-based appearance model using RGB-D data is proposed which makes the appearance model robust to scale change, partial occlusion and view-truncation. The introduce of RGB-D data increases the diversity of features, which provides more types of features for feature selection in data association and enhances the final multi-tracking performance. We validate our method from several aspects including scene-adaptive feature selection scheme, hierarchical data association scheme and RGB-D based appearance modeling scheme in various indoor scenes, which demonstrates its effectiveness and efficiency on improving multi-tracking performances in various indoor scenes.展开更多
以普通铝粉、卤代烃、氢化钠和H2等为主要原料,在常压低于100℃的条件下,采用铝的格氏试剂法,成功制备出氢化铝钠Na Al H4。通过FTIR、XRD表征,结合元素分析,研究其成分及结构,表明样品为氢化铝钠,实际与理论产率比值达到90%以上;根据SE...以普通铝粉、卤代烃、氢化钠和H2等为主要原料,在常压低于100℃的条件下,采用铝的格氏试剂法,成功制备出氢化铝钠Na Al H4。通过FTIR、XRD表征,结合元素分析,研究其成分及结构,表明样品为氢化铝钠,实际与理论产率比值达到90%以上;根据SEM和online MS,对其进行表面形貌和稳定性研究。结果显示,晶体结构较完整,室温下稳定性好,自身储氢量与市售样品相当。该方法实现了常压下氢化铝钠的制备,且反应在常压下进行,产率和原料利用率都达到了工业要求,对其生产工艺的改进具有促进作用。展开更多
基金Project supported by the Science and Technology Department of Guangdong Province,China(No.2016B090918118)
文摘Phenolics,as the main bioactive compounds in tea,have been suggested to have potential in the prevention of various human diseases.However,little is known about phenolics and their bioactivity in Zhangping Narcissue tea cake which is considered the most special kind of oolong tea.To unveil its bioactivity,three phenolic-enriched extracts were obtained from Zhangping Narcissue tea cake using ethyl acetate,n-butanol,and water.Their main chemical compositions and in vitro bioactivity were analyzed by high-performance liquid chromatography(HPLC)and ultraperformance liquid chromatography-mass spectrometry(UPLC-MS).The ethyl acetate fraction(ZEF)consisted of higher content of phenolics,flavonoids,procyanidins,and catechin monomers(including epigallocatechin gallate(EGCG),epicatechin gallate(ECG),and gallocatechin gallate(GCG))than n-butanol fraction(ZBF)and water fraction(ZWF).ZEF exhibited the strongest antioxidant capacity in vitro due to its abundant bioactive compounds.This was validated by Pearson correlation and hierarchical clustering analyses.ZEF also showed a remarkable inhibition on the growth,migration,and invasion of 4T1 murine breast cancer cells.
文摘Explosive synchronization(ES)is a kind of first-order jump phenomenon that exists in physical and biological systems.In recent years,researchers have focused on ES between single-layer and multi-layer networks.Most research on complex networks with delay has focused on single-layer or double-layer networks,multi-layer networks are seldom explored.In this paper,we propose a Kuramoto model of frequency weights in multi-layer complex networks with delay and star connections between layers.Through theoretical analysis and numerical verification,the factors affecting the backward critical coupling strength are analyzed.The results show that the interaction between layers and the average node degree has a direct effect on the backward critical coupling strength of each layer network.The location of the delay,the size of the delay,the number of network layers,the number of nodes,and the network topology are revealed to have no direct impact on the backward critical coupling strength of the network.Delay is introduced to explore the influence of delay and other related parameters on ES.
基金financially supported by the National Natural Science Foundation of China(No.11372110)
文摘Nb-Mo-ZrB2 composites （V（Nb）/V（Mo） = 1） with 15v01% or 30v01% of ZrB2 were fabricated by hot-pressing sintering at 2000~C The phases, microstxucture, and mechamcal properties were then investigated. The composites contain Nb-Mo solid solution （denoted as （Nb, Mo）ss hereafter）, ZrB, MoB, and NbB phases. Compressive strength test results suggest that the strength of Nb-Mo-ZrB2 composites increases with increasing ZrB2 content; Nb-Mo-30vol%ZrB2 had the highest compressive strength （1905.1 MPa）. The improvement in the compressive strength of the Nb-Mo-ZrB2 composites is mainly attributed to the secondary phase strengthening oftke stiffer ZrB phase, sol- id-solution strengthening oftke （Nb, Mo）ss matrix as well as fme-grain strengtkening. The fracture toughness decreases with increasing ZrB2 content. Finally, the fracture modes oftke Nb-Mo-ZrB2 composites axe also discussed in detail.
文摘It is difficult to solve complete coverage path planning directly in the obstructed area. Therefore, in this paper, we propose a method of complete coverage path planning with improved area division. Firstly, the boustrophedon cell decomposition method is used to partition the map into sub-regions. The complete coverage paths within each sub-region are obtained by the Boustrophedon back-and-forth motions, and the order of traversal of the sub-regions is then described as a generalised traveling salesman problem with pickup and delivery based on the relative positions of the vertices of each sub-region. An adaptive large neighbourhood algorithm is proposed to quickly obtain solution results in traversal order. The effectiveness of the improved algorithm on traversal cost reduction is verified in this paper through multiple sets of experiments. .
文摘Recently, approaches utilizing spatial-temporal features to form Bag-of-Words （BoWs） models have achieved great success due to their simplicity and effectiveness. But they still have difficulties when distinguishing between actions with high inter-ambiguity. The main reason is that they describe actions by orderless bag of features, and ignore the spatial and temporal structure information of visual words. In order to improve classification performance, we present a novel approach called sequential Bag-of-Words. It captures temporal sequential structure by segmenting the entire action into sub-actions. Meanwhile, we pay more attention to the distinguishing parts of an action by classifying sub- actions separately, which is then employed to vote for the final result. Extensive experiments are conducted on challenging datasets and real scenes to evaluate our method. Concretely, we compare our results to some state-of-the-art classification approaches and confirm the advantages of our approach to distinguish similar actions. Results show that our approach is robust and outperforms most existing BoWs based classification approaches, especially on complex datasets with interactive activities, cluttered backgrounds and inter-class action ambiguities.
基金This work is supported by National Natural Science Foundation of China （NSFC, No. 61340046）, National High Technology Research and Development Program of China （863 Program, No. 2006AA04Z247）, Scientific and Technical Innovation Commission of Shenzhen Municipality （JCYJ20130331144631730, JCYJ20130331144716089）, Specialized Research Fund for the Doctoral Program of Higher Education （No. 20130001110011）.
文摘Indoor multi-tracking is more challenging compared with outdoor tasks due to frequent occlusion, view-truncation, severe scale change and pose variation, which may bring considerable unreliability and ambiguity to target representation and data association. So discriminative and reliable target representation is vital for accurate data association in multi-tracking. Pervious works always combine bunch of features to increase the discriminative power, but this is prone to error accumulation and unnecessary computational cost, which may increase ambiguity on the contrary. Moreover, reliability of a same feature in different scenes may vary a lot, especially for currently widespread network cameras, which are settled in various and complex indoor scenes, previous fixed feature selection schemes cannot meet general requirements. To properly handle these problems, first, we propose a scene-adaptive hierarchical data association scheme, which adaptively selects features with higher reliability on target representation in the applied scene, and gradually combines features to the minimum requirement of discriminating ambiguous targets; second, a novel depth-invariant part-based appearance model using RGB-D data is proposed which makes the appearance model robust to scale change, partial occlusion and view-truncation. The introduce of RGB-D data increases the diversity of features, which provides more types of features for feature selection in data association and enhances the final multi-tracking performance. We validate our method from several aspects including scene-adaptive feature selection scheme, hierarchical data association scheme and RGB-D based appearance modeling scheme in various indoor scenes, which demonstrates its effectiveness and efficiency on improving multi-tracking performances in various indoor scenes.
文摘以普通铝粉、卤代烃、氢化钠和H2等为主要原料,在常压低于100℃的条件下,采用铝的格氏试剂法,成功制备出氢化铝钠Na Al H4。通过FTIR、XRD表征,结合元素分析,研究其成分及结构,表明样品为氢化铝钠,实际与理论产率比值达到90%以上;根据SEM和online MS,对其进行表面形貌和稳定性研究。结果显示,晶体结构较完整,室温下稳定性好,自身储氢量与市售样品相当。该方法实现了常压下氢化铝钠的制备,且反应在常压下进行,产率和原料利用率都达到了工业要求,对其生产工艺的改进具有促进作用。
