Delineating travel patterns and city structure has long been a core research topic in transport geography. Different from the physical structure, the city structure beneath the complex travel-flow system shows the inherent connection patterns within the city. On the basis of massive taxi trip data of Shanghai, we built spatially-embedded networks to model the intra-city spatial interactions and introduced network science methods into the issue. The community detection method is applied to reveal sub-regional structures, and several network measures are used to examine the properties of sub-regions. Considering the differences between long-and short-distance trips, we reveal a two-level hierarchical polycentric city structure of Shanghai. Further explorations on sub-network structures demonstrate that urban sub-regions have broader internal spatial interactions, while suburban centers are more influential in local traffic. By incorporating the land use of centers from the travel pattern perspective, we investigate sub-region formation and center-local places interaction patterns. This study provides insights into using emerging data sources to reveal travel patterns and city structures, which could potentially aid in applying urban and transportation policies. The sub-regional structures revealed in this study are more easily interpreted for transportation-related issues than other structures, such as administrative divisions.

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High levels of reactive oxygen species (ROS), which may be associated with reduced sperm quality, can be detected during cryopreservation of sperm of some species. Our objective was to investigate whether the addition of antioxidants to cryopreservation extenders influenced post-thaw sperm characteristics and fertility in Acipenser dabryanus, Acipenser sinensis and Acipenser baerii. Prior to freezing, sperm samples were diluted with a base extender as control or in extender supplemented with catalase (CAT), glutathione (GSH), cysteine (NAC), ascorbic acid (VC) or their paired combinations. Protective concentrations of CAT, GSH and VC in the three species were 25 U/ml, 0.25-0.5 mg/ml and 0.5 mg/ml, respectively. Cysteine showed no protective effect against ROS. The addition of CAT, GSH and VC positively affected either acrosome or membrane integrity of post-thawed sperm in the three species, as well as spermatozoan motility in A. sinensis. The combination of antioxidants did not show a positive synergistic effect. This study suggested that the use of antioxidants in the cryopreservation of sturgeon sperm has potential to decrease intracellular ROS, and consequently preserve acrosome and membrane integrity, as well as spermatozoan motility.

Considering the importance of user-innovation knowledge to product and service innovation, this paper proposed knowledge discovering and analyzing methods on user-innovation communities based on weighted knowledge network (WKN). First, web mining methods were used for getting forum posts in virtual user-innovation communities, then the acquired keywords and the statistical data were processed and integrated into a WKN model. Next, based on the WKN model, the paper proposed new methods to discover the core innovation knowledge, the developing innovation knowledge and the potential innovation knowledge through analyzing the structure of WKN model, including weights of nodes and edges, cliques, the strong or weak ties, etc. Finally, Xiaomi community was taken as the study case to verify the validity of the methods. Compared with the existing method of user knowledge discovery, the presented methods are more quantitatively, conveniently and visually and provide new tools to study and utilize the user-innovation knowledge in enterprise virtual communities.

The minerals in the hydrothermal and cold seep system form at different temperatures and show responses to the laser power to varying degrees. Here, we focus on the heat-induced by laser to study thermal transformations of the chalcopyrite, covellite, pyrite, barite, and aragonite based on Raman spectroscopy. Chalcopyrite mainly transforms into hematite, and covellite mainly transforms into chalcocite with the increase of laser power. Interestingly, comparing with the previous study, the pyrite can transform to the marcasite firstly, and form hematite finally. We also find that high-temperature opaque chalcopyrite is more likely to occur thermal transformations due to the smaller absolute energy difference (|ΔE1|) based on the frontier orbital theory. In contrast, the oxysalt minerals won’t transform into new components under high laser power. However, the structure of the barite has been destroyed by the high laser power, while the more transparent aragonite is not affected by the high laser power due to the laser penetrates through the transparent aragonite crystal and causes little heat absorption. Finally, we established the minimum laser power densities for thermal transformations of these minerals formed under different environments. The above study provides a simple way to study the thermal transformations of minerals by the local heat-induced by laser and also enlightens us to identify the minerals phases precisely.