In this paper, a novel structure of a compact UWB slot antenna and its design optimization procedure has been presented. In order to achieve a sufficient number of degrees of freedom necessary to obtain a considerable size reduction rate, the slot is parameterized using spline curves. All antenna dimensions are simultaneously adjusted using numerical optimization procedures. The fundamental bottleneck here is a high cost of the electromagnetic (EM) simulation model of the structure that includes (for reliability) an SMA connector. Another problem is a large number of geometry parameters (nineteen). For the sake of computational efficiency, the optimization process is therefore performed using variable-fidelity EM simulations and surrogate-assisted algorithms. The optimization process is oriented towards explicit reduction of the antenna size and leads to a compact footprint of 199 mm2 as well as acceptable matching within the entire UWB band. The simulation results are validated using physical measurements of the fabricated antenna prototype.

Through partially replacing Y element, Ce was added into near-equiatomic AlNiY medium-entropy amorphous alloy (denoted as MEAA) ribbons by the melt spinning process in this study. The differences of microstructure, thermal stability, hardness and corrosion resistance of Al33.3Ni33.3Y33.4-xCex (x = 0, 2, 5, 8, 13) alloy ribbons were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimeter (DSC) and Vickers-type hardness tester. The anti-corrosion performance in 3.5 wt.% NaCl solution of alloy ribbons was investigated elaborately through the general potentiodynamic polarization curves (Tafel) and electrochemical impedance spectroscopy (EIS). Results suggested that all ribbon samples could remain amorphous structure and the hardness are all above 510 HV0.1. With the increase of Ce content, the thermal stability begins to be gradually lower. However, according to the analysis of crystallization kinetics, all types of MEAA ribbons presents the relatively prominent thermal stability compared with traditional Al-based amorphous alloys. The corrosion current density raises firstly, then shows a decreasing trend, and has a slight increase at last. Therefore, appropriate content of Ce element can improve the corrosion protection performance of alloy ribbons and the 5 at.% Ce MEAA ribbons exhibited the excellent corrosion resistance in this study.

This paper deals with the subject of high temperature analysis of refining slags originating from a ladle from an actual/industrial secondary refining process. The objective of the conducted research was to learn about the rheological behaviour of the complex industrial slag systems analysed in conditions of variable rheological parameters and temperature, also analyses with a high-temperature microscope. The analysed system seems to be a Newtonian body (with viscosity between 0.1 and 0.8 Pa·s, depend on temperature value, and chemical composition).