Cuiling Hou

Microwave absorption properties of rare metal-doped multi-walled carbon nanotube/polyvinyl chloride composites

Using rare metal nitrate-doped multi-walled carbon nanotubes as the absorber and polyvinyl chloride as the matrix, the microwave electromagnetic and absorbing properties of multi-walled carbon nanotube/polyvinyl chloride composites were studied. The complex permittivity of the composites doped with different rare metal nitrate decreased in the frequency region of 8.2–12.4 GHz. The minimum reflection loss of rare metal nitrate-doped multi-walled carbon nanotube/polyvinyl chloride composites decreased and shifted slightly to the higher frequency region, and the absorption bandwidth (<−10 dB or >90%) increased in the frequency range of 8–18 GHz compared to multi-walled carbon nanotube/polyvinyl chloride composites. The reflection loss (<−10 dB) of 0.2 wt% La(NO3)3-doped multi-walled carbon nanotube/polyvinyl chloride composites is the widest from the absorption bandwidth (maximum is 5.12 GHz).

Electromagnetic and mechanical properties of Fe3O4-coated amorphous carbon nanotube/polyvinyl chloride composites

Abstract Electromagnetic wave absorbing properties of absorbing composites depend on the dielectric and magnetic loss generally. In this paper, using Fe3O4-coated amorphous carbon nanotubes (ACNTs-Fe3O4) fabricated using a chemical synthesis–hydrothermal treatment method as an absorber and polyvinyl chloride (PVC) as a matrix, electromagnetic and mechanical properties of ACNT-Fe3O4/PVC composite were investigated. The results showed that the dielectric and magnetic losses of ACNT-Fe3O4/PVC composite were significantly enhanced in 8.2–12.4 GHz compared to ACNT/PVC composite, which improved absorbing properties, while slightly changing the mechanical properties.

A comparative study of the characteristics and carbonization behaviors of three modified coal tar pitches

Abstract Coal tar pitch (CTP) was modified either with 10 g cinnamaldehyde (CMA) per 100 g CTP, 7 g p-toluene sulfonic acid (PTS) per 100g CTP, or a mixture of 10 g CMA and 7 g PTS per 100 g CTP. The parent CTP and the modified CTPs were characterized by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis. The four samples were carbonized at different temperatures and the products were characterized by FT-IR and polarized-light microscopy. Results show that the modifications have a large influence on the characteristics and carbonization behavior of the CTP. The distillation of CMA occurs at a temperature lower than 300 °C during the carbonization of the CMA-modified CTP. Methyl and methylene groups of the parent CTP and the modified CTPs gradually disappear with increasing temperature during carbonization. The modification of the CTP with the mixture of CME and PTS results in a highest increase (5.08%) of carbonization yield and the most abundant mesophase sphere formation during carbonization.

Modulation of the Acher’s limit by medium thickness in [FeCoB/ZnO]50 multilayers

Abstract This work investigates the high frequency characteristics of [FeCoB/ZnO]50 multilayers with different ZnO thickness. The results reveal that the Acher’s limit of [FeCoB/ZnO]50 multilayers can be modulated by medium thickness. Increasing medium layer thickness is favorable for breaking through the Acher’s limit. It is found that the differences of Acher’s limit between multilayers and single layers are caused by magnetic interface anisotropy related to interface roughness and some unknown factor. Graphical Abstract