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Ultrafine one-dimensional WO3 nanorods (NRs) with diameters of 10–200 nm have been fabricated using a hydrothermal synthesis method. The optical performance of the WO3 NRs strongly depends on their various defects as well as their crystal quality. Upon exposure to trace quantities of ethanol gas, the photoluminescence (PL) spectra of these nanorod samples under ultraviolet illumination showed a large variation in intensity. WO3-NR-based ethanol gas sensing via PL spectra variation demonstrated a 100 ppm sensitivity detection limit and a wide linear detection range of 200–2000 ppm at 100°C. This outstanding optical ethanol sensing performance can be ascribed to the very large surface area to volume ratio of this material, which increases the density of active sites for ethanol adsorption and reaction with adsorbed oxygen species.

Ensuring the sustainability of the European power system is one of the key priorities in the implementation of the EU’s ambitious plans to become climate-neutral by 2050. The uniqueness of the power systems of the EU member states necessitates their assessment and comparison. The article offers a composite indicator, namely, the power system sustainability index (PSS index), to assess the current level of the development of the power systems via three dimensions (social, economic, and environmental) and eight local indicators: the household electricity consumption per capita; the commercial electricity consumption per GDP; the external dependency of the power system; the energy efficiency of the generation; the capacity utilization factor; the share of organic fossil fuels; the share of renewable energy resources; and the greenhouse gas (GHG) emissions per unit of primary energy source. The “energy mix” is defined as the key impact factor, which has a contradictory effect on the local power system sustainability (LPSS) indicators, which can be represented as a set of regression models. The data of the regression analysis can be used for performing a multiobjective optimization by the local indicators, and they can determine the vectors of change required to ensure the sustainability of the power system. The research results prove that it is possible to minimize the GHG emissions per unit of primary energy source and maximize the energy efficiency of generation, while reducing the capacity utilization and increasing the external dependency of the power system.

Novel optical gas-sensing materials for Au nanoparticle (NP)-modified ZnO nanorod (NR) arrays were fabricated using hydrothermal synthesis and magnetron sputtering on Si substrates. The optical performance of ZnO NR can be strongly modulated by the annealing temperature and Au sputtering time. With exposure to trace quantities of oxygen, the ultraviolet (UV) emission of the photoluminescence (PL) spectra of Au/ZnO samples at ~390 nm showed a large variation in intensity. Based on this mechanism, ZnO NR based oxygen gas sensing via PL spectra variation demonstrated a wide linear detection range of 10–100%, a high response value, and a 1% oxygen content sensitivity detection limit at 225 °C. This outstanding optical oxygen-sensing performance can be attributed to the large surface area to volume ratio, high crystal quality, and high UV emission efficiency of the Au NP-modified ZnO NR arrays. Density functional theory (DFT) simulation results confirmed that after the Au NPs modified the surface of the ZnO NR, the charge at the interface changed, and the structure of Au/ZnO had the lowest adsorption energy for oxygen molecules. These results suggest that Au NP-modified ZnO NR are promising for high-performance optical gas-sensing applications.

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Laser as a high energy density light source and silicon cell as a widely used photoelectric conversion element, the interaction between the two has become a research hotspot in wireless energy transmission and semiconductor material damage. At present, the experimental and theoretical research mainly focuses on the damage threshold and morphology, electrical output characteristics and action mechanism. The resistance of the silicon cell affecting electrical output was mainly qualitative analysis, but few quantitative studies. Different degrees of damage were simulated though pulsed laser irradiation in different positions of the silicon cell. The parallel resistance and series resistance of the silicon cell were estimated by linear fitting at V0 and I0 of IV curve, and the variation of the resistances was quantitatively obtained under different degrees damage. The results show that the damage induced by pulsed laser irradiation is obvious melting ablation and the damage is irreversible when the optical power density is 3.3×108W / cm2 , one pulse irradiation damage is equivalent to the resistances of 67 in parallel and 189 m in series for silicon cell, the output voltage decreases approximately linearly with the increase of irradiation times and the output voltage is about half of the initial voltage after 6 times irradiation. In addition, the output voltage was rapidly increased to a peak with the loading of pulsed laser, which is almost independent of the damage of the silicon cell.

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Abstract. The problem of wave drag reduction with high-frequency repetitive laser pulse energy depositions is multivariable. Three key non-dimensional parameters, non-dimensional energy, non-dimensional depositing position and Mach number, were constructed from a number of original variables by using Buckingham pi theorem. Influences of these non-dimensional parameters on energy deposition performance, namely drag reduction and energy deposition efficiency, were investigated numerically by solving three-dimensional Navier-Stokes equations with an upwind scheme. Optimizing method of non-dimensional energy and non-dimensional depositing position is proposed. Drag reduction and energy deposition efficiency have exponential relationships with non-dimensional energy; Drag reduction and energy deposition efficiency have quadratic relationships with non-dimensional depositing position. Drag reduction has exponential relationship with freestream Mach number and energy deposition efficiency has quadratic relationship with Mach number. Non-dimensional laser energy and non-dimensional depositing position should be optimized synthetically for a given freestream.