Mobile Networks and Applications - 5G/6G communication are first generation high speed wireless communication network which integrates the aerial data, terrestrial data and maritime data via... 相似文献
Nickel-free solid oxide fuel cell anodes are an object of study for applications that aim at utilising primary carbonaceous fuels to generate power. In this study, a ceria-Co-Cu anode is produced and tested with hydrogen, methane and ethanol fuels at various temperatures.The produced catalysts were characterised by X-ray analysis and H2 temperature-programmed reduction (TPR). Catalytic tests were performed and compared with the material under electrochemical operation. The cells were electrochemically characterised by recording i-V plots. The samples were assessed post-test for eventual carbon deposits by Raman spectroscopy investigations and temperature-programmed oxidation (TPO) analysis.The cells were able to operate with hydrogen, methane as well as ethanol, directly fed to the anode, with maximum power densities ranging from 400 to 540 mW.cm−2, depending on the fuel stream utilised. The cells also kept their integrity demonstrating coking resistance for over 24 h of continuous operation. Important discussions and conclusions are drawn about carbon formation and the role of each compound in the anode composition. The bimetallic cell (ceria-Co-Cu) is herein compared to monometallic ones (ceria-Co and ceria-Cu) that served as baselines. The advantages of the bimetallic composition are listed and evaluated throughout the discussions. 相似文献
The work presents the kinetic effect of nanometric BaF2 and CaF2 particles on kaolinite to mullite transformation. The kinetics were evaluated from dilatometric data using two different non-isothermal procedures: conversional model-fitting method and diffusional sintering analysis. From experimental data, the activation energy of mullite formation calculated from sintering (942 kJ/mol) and from conversional method (910 kJ/mol) were in good agreement with those values reported by other authors (mean value 1030 kJ/mol). After incorporation of 3 mol% of nanometric BaF2 and CaF2 in kaolinite and applying both analytical procedures, lower activation energies for mullite formation were obtained, assigning to the transformation the value of 635 kJ/mol for kaolinite/BaF2 and 428 kJ/mol for kaolinite/CaF2 composites. 相似文献
This work is devoted to the stress–strain state of isotropic double curved shell with defect system. The construction is weakened by two non-through thickness (internal) cracks of different length and by a circular hole located between cracks. In this study we use the line-spring model. Within the framework of this model cracks are modeled as mathematical cuts of shell’s middle surface. This leads to a two-dimensional problem. The problem is reduced to a system of eight boundary integral equations. To ensure the uniqueness of solution an additional equation is added. In the numerical solution of the problem special quadrature formulas for singular integrals of Cauchy type and the finite difference method are applied. The influence of defects on each other for double curved shell has been investigated. The given theoretical results can be used for the calculation of structural elements with holes, cracks on the strength and fracture toughness in various branches of engineering. 相似文献
This paper focuses on dealing with the tracking challenges such as target occlusion and deformation. It proposes a new tracking method via extracting and evaluating multi-features for both target region and its adjacent surroundings. The multi-features separately describe the key factors to detect target including the color feature, the shape and contour feature, and the distributions of structure and intensity described by the Pearson Correlation Coefficient. These multi-features are proposed as the basic representation of target template and candidates and used to define a matching algorithm between them. The best matched candidate is taken as the final tracking result. To improve the efficiency of target template and candidates, the region of importance (ROI) for target is proposed by evaluating the distribution of salient values on many extended regions. The ROIs produce more accurate regions to form target template and candidates. Finally, a new template update method is defined based on the precision of tracked result to adapt to target state and achieve the follow target tracking. Using 25 videos in visual tracking benchmark, we achieve the quantitative and qualitatively evaluations of 12 different trackers. Many experiments demonstrate that our tracker produces much better results than the present trackers in dealing with target occlusion, deformation, rotation, background clutters.
In this work, we propose a modulation doping strategy for simultaneous achievement of low lattice thermal conductivity and high Seebeck coefficient in the Cu2GeSe3 compound. The Ag and In dual-doping can optimize the hole carrier concentration to balance electrical conductivity and Seebeck coefficient, achieving a high power factor of ~6.4 μW cm?1 K?2 for the Cu2GeSe3 compound. The Ag point defect makes a great contribution to blocking the propagation of phonons besides the phonon-phonon Umklapp process, yielding a minimum lattice thermal conductivity of ~0.38 W m–1 K–1. Remarkably, a maximum ZT value of ~0.97 at 723 K is achieved for Cu1.8Ag0.2Ge0.95In0.05Se3 compound, which is the highest value for the Cu2GeSe3-based systems in the temperature range of 323–723 K. 相似文献
Operator error in diagnosis and execution of task have significant impact on Nuclear Power Plant (NPP) safety. These human errors are classified as mistakes (rule base and knowledge based errors), slip (skill based) and lapses (skill based). Depending on the time of occurrence, human errors have been categorized as i) Category ‘A’ (Pre-Initiators): actions during routine maintenance and testing wherein errors can cause equipment malfunction ii) Category ‘B’ (Initiators): actions contributing to initiating events or plant transients iii) Category ‘C’ (Post-Initiators): actions involved in operator response to an accident. There have been accidents in NPPs because of human error in an operator's diagnosis and execution of an event. These underline the need to appropriately estimate HEP in risk analysis. There are several methods that are being practiced in Probabilistic Safety Assessment (PSA) studies for quantification of human error probability. However, there is no consensus on a single method that should be used. In this paper a method for estimating HEP is proposed which is based on simulator data for a particular accident scenario. For accident scenarios, the data from real NPP control room is very sparsely available. In the absence of real data, simulator based data can be used. Simulator data is expected to provide a glimpse of probable human behavior in real accident situation even though simulator data is not a substitute for real data. The proposed methodology considers the variation in crew performance time in simulator exercise and in available time from deterministic analysis, and couples them through their respective probability distributions to obtain HEP. The emphasis is on suitability of the methodology rather than particulars of the cited example. 相似文献
The oxidation resistance of ultra-high-temperature ceramic material (HfB2-30 vol%SiC)-2 vol%rGO (rGO: reduced graphene oxide) under long-term exposure (2000s) to a supersonic air flow has been studied. The ceramics were obtained by reactive hot pressing of HfB2-(SiO2-C)-rGO composite powder at a temperature of 1800°C (pressure 30 MPa, holding time 15 min, Ar). The surface temperature of graphene-modified ceramics under the influence of heating by high-enthalpy air flow (heat flow q reached 779 W·cm–2) did not exceed 1700°C, which is 650–700°C less than for the HfB2-30 vol%SiC baseline ceramics. This may be related to an increase in the efficiency of heat transfer from the sample to the water-cooled module, due to the higher thermal conductivity of the rGO-containing material. Thereby, a decrease in the material degradation degree has been noted, i.e. decrease in the recession rate and decrease in the total thickness of the oxidised ceramic layer by tenth. The peculiarities of the oxidised surface and near-surface region microstructure upon aerodynamic heating of the graphene-modified ceramic material, have been shown. 相似文献