It is suggested to use a new nanocomposite material—nanostructures of copper-doped zinc sulfide in a matrix of porous aluminum oxide—as a light-emitting layer of electroluminescent sources of light. The material was deposited by thermal evaporation in a vacuum. The microstructure of the layers, impurity distribution in the electroluminescent-phosphor layer, and electroluminescence spectra at various copper concentrations in ZnS:Cu were studied. 相似文献
Automated fiber placement (AFP) process can be used to manufacture laminates by laying up unidirectional slit tapes along a desired path and placing multiple layers on top of each other. Usually, the slit tapes are placed direct onto the tooling to attain the final part geometry. Alternatively, the laminate can be built up on a planar substrate and can be subsequently formed into the final shape. This kind of processing allows manufacturing highly curved parts, which may not be possible with the direct placement. In the present work a forming simulation of thick AFP laminates is developed to predict the tapes’ orientations and delamination as well as transverse tape spread-ups and separations during the forming process. The simulation model is built up through the material characterization experiments. Validation is performed comparing the results of the simulation vs. the experimental forming on two generic geometries. An optical inspection is made on the external layers of the laminates. In a second step, live computer tomography (CT) scans are used to inspect the tapes within an AFP laminate during forming of an L- and a Z-flange. Tapes re-orientation, gaps and tapes widening are observed experimentally and compared to the simulation results. The simulation is capable to predict the tows orientation and provides indicators concerning the tows spread-up and separation. 相似文献
The different energy transition efforts in the EU-27 countries are analysed, paying special attention to the achievement of set energy targets and the real influence on energy dependence and GHG reduction. Various methodologies were used, ranging from construction of timelines to geo-statistical analysis using Geographic Information Systems (GIS) and the implementation of machine learning techniques and models, using R. The results show how different modifications of the energy saving and efficiency targets, along with lower power consumption due to the COVID pandemic, resulted in that although most of the EU-27 countries have achieved their saving and efficiency targets, this has not been reflected in a real reduction in consumption (compared to 1990 levels). In addition, the fulfilment of the objectives has not resulted in a reduction in energy dependence, generating a false sense of security and satisfaction in the fulfilment of the targets. Concerning GHGs, almost all EU-27 countries decrease their GHG emissions per capita compared to 2000 (with the exception of Lithuania, Bulgaria, Croatia and Latvia), with this decrease being mainly related to the fulfilment of renewable energy targets in transport. The conclusion highlights the need to make greater efforts to achieve saving and efficiency in the near future; otherwise, higher power consumption via renewable energy sources, while helping meet future increases in energy demand, will not impact the reduction in energy dependence compared to current levels.
Graphical abstract
Achievement of energy transition targets. Contribution to the reduction in greenhouse gases and energy dependence.
