In order to enhance the effectiveness of pollutant removal by photocatalysis under visible light, a multifunctional photocatalyst was prepared by grafting polydopamine (PDA) with the core-shell nanocomposite Fe 3 O 4 @SiO 2 @TiO 2 (FST). The structural, morphological, and magnetic responses of FST@PDA were characterized by X-ray diffraction pattern, Fourier transform infrared spectroscopy, transmission electron microscopy, etc. FST@PDA showed a high degradation rate of rhodamine B, reaching 98.7 % and 95.7 % after 150 min of ultraviolet and visible light radiation, respectively. In addition, the prepared FST@PDA had good safety and high recyclability due to the strong covalent bonds between FST and PDA.

Recycling the polymer material from the waste has a great advantage in reducing the cost of the biodegradable hot melt adhesive and solving environmental problems. Cellulose diacetate obtained from the acid hydrolysis of discarded cellulose triacetate‐based cinematographic films was blended with low molecular weight partially saponified polyvinyl acetate. The degree of substitution of cellulose diacetate and the degree of saponification of partially saponified polyvinyl acetate to obtain the binary blends having excellent compatibility were determined by FTIR and DSC. TGA showed that these blends have sufficient thermal stability for hot melt adhesive applications. The viscoelastic properties of the blends were evaluated by DMA and melt viscosity. The shear strength and the biodegradability of the final hot melt adhesive were examined according to the amount of cellulose diacetate in the blends. The results indicate that adding 20% of cellulose diacetate can reduce the cost of partially saponified polyvinyl acetate ‐based hot melt adhesive while improving the adhesive strength.

The transmission characteristics of electromagnetic (EM) waves in a semicircular plasma filament layer generated by a femtosecond laser were studied in a wide frequency band including radar waves. We have focussed on the influence of plasma parameters and filament arrangement based on the diffraction and superposition theory of EM waves on the transmittance. A numerical simulation model using the current density convolution finite‐difference time‐domain method was constructed in a semicircular multilayer filament structure, and the transmission characteristics of spherical EM waves were examined. The simulation results showed that in this semicircular structure, the transmittance was periodically changed at a frequency interval corresponding to the thickness of the filament channel. This phenomenon was more pronounced as the number of the filament layers increased. In the lower band (<30 GHz), there was little change in the transmittance according to layer‐to‐layer distance, but in the higher band (>30 GHz), it changed irregularly. On the contrary, for the electron number density, it changed regularly in the lower frequency and hardly changed in the higher frequency. When the number of layers was 3 or more, the transmittance became 0 at the centre of the channel, and a discontinuous interference pattern appeared more clearly as the frequency increased.

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