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Abstract: In a mobile service robot, map building is a basis for navigation that allows the robot to perform a given task. When robots carry on mission planning and execution, they not only need structural information about the environment to navigation and self localization, but also need to possess a deeper knowledge to endow a robot with higher degrees of autonomy and intelligence. In this paper, the QR code based artificial labels are used to provide semantic concepts and relations of objects and rooms in indoor environments, which can solve the complexity and limitations of semantic recognition and scene understanding only with robot’s vision. Semantic knowledge offered by artificial labels is obtained to incarnate semantic representations of the environment, which are formed as the semantic map. In order to maintain the navigation abilities of the robot, the spatial modeling method of a human is imitated to describe the relations of function area as a global topological map by the spectrum clustering algorithm. The semantic map is combined with topological representations to build a spatial semantic hybrid map. Using the hybrid map, “semantic” path planning, the elementary management of objects, and the context based robot localization are studied to show the hybrid map’s practicability. The results of several experiments show that the spatial semantic hybrid map comes up to capture the human point-of-view of robot environments, enable a high-level reasonable service path, and achieve function-driven navigation. [Copyright &y& Elsevier]

Mg-doped Li 1.2-x Mg x Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode materials were prepared by a molten salt method. Our results showed that the introduction of NaCl is rather important and will provide a fusion environment, which not only leads to an evenly distribution of the transition metals within the cathode materials but is also helpful for the formation of a unique two dimensional (2D) nano structures. Mg doping results in a structural variation of the cathode materials, leading to a continuous increase of the capacity at the first dozen cycles. Although Mg doping can significantly improve the rate capability, the cycling stability, and the capacity retention of the cathode materials, a large Mg doping amount (>6%) will cause the formation of impurity phases, which in turn reduce the electrochemical performance of the materials. Electrochemical impedance spectroscopy (EIS) measurement showed that the charge transfer resistance was reduced significantly due to Mg doping, and 4% Mg-doped sample exhibits promising lithium diffusion kinetics and rate capability. [ABSTRACT FROM AUTHOR]

Na 2 Li 2 Ti 6 O 14 was successfully prepared by a solvothermal method. The XRD patterns show that the as-prepared samples have good purity and crystallinity. Further Rietveld refinement and theoretical calculation suggested that lithium should occupy 16n and 8e sites of the lattice during the intercalation process, and nearly six lithiums can be inserted reversibly into the lattice. The amount of ammonium hydrogen carbonate added during the reactions have significant impacts on the structures and morphologies of the materials, and well-defined hierarchical and porous spheres can be obtained at a suitable condition. The electrochemical tests showed that the charge/discharge specific capacities of the four samples under a current density of 50 mA g −1 after 50 cycles are 103.9/104.3, 175.1/177.1, 191.9/194.1, and 138.4/140.4 mA h g −1 , suggesting that the performance of the NLTO-L-3 is much better than other samples. Furthermore, NLTO-L-3 also exhibits good cycling stability and rate capability, and its revisable capacity is about 93 mA h g −1 at 2.8 A g −1 after 500 cycles. The excellent performance can be attributed to the hierarchical structures and porous characteristics. These features are helpful for reducing the impedance and for improving the diffusion dynamics of materials, as further confirmed by EIS measurement. [ABSTRACT FROM AUTHOR]

Low efficiency of oxygen reduction reaction (ORR) across cathode interfaces constitutes an obstacle to the bioelectricity generation in microbial fuel cells (MFCs). Advances in the property of carbon-based catalysts for ORR will have far-reaching implications for MFCs. Melamine is used as both carbon and nitrogen sources for preparing nitrogen-doped Fe-species/partly-graphitized carbon (Fe-species/NPGC) catalysts at relatively low temperature (640–700 °C). Main crystalline phases in Fe-species/NPGC- x ( x = 640, 650, 660 and 700) change from iron carbide (Fe 3 C) to α-Fe as temperature increases. The O C O groups and structurally-bonded nitrogen (Fe-bonded N, pyridinic N and pyrrolic N) in PGC skeleton are favorable for improving electrical conductivity and catalytic activity. Single chamber MFCs with Fe/Fe 3 C/NPGC-650 generate power density of 1323 mW m −2 , which is higher than those of Fe-species/NPGC- x ( x = 640, 660 and 700) and Pt/C (1191 mW m −2 ). Minimum power density decline (1.75%) is achieved by Fe/NPGC-660, which is far lower than that (17.11%) of Pt/C. The highest coulombic efficiency (30%) is obtained by Fe/Fe 3 C/NPGC-650 due to the sufficient active-sites (embedded Fe 3 C or Fe N species) and easy charge transport across the triphase interfaces, which are conducive to “capture–consume” the electrons for catalyzing ORR. [ABSTRACT FROM AUTHOR]