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Your search keyword '"Nie, Wenjun"' showing total 15 results
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15 results on '"Nie, Wenjun"'

14. Magnetic-medium–based metamaterial for broadband microwave absorption and multiband transmission characteristics

Author

He Junzhe, Zhao Yilun, Nie Wenjun, Chong Wang, Zhihong Wu, Yang Zhihui, Yang Zhou, Zhang Jiulin, Sun Xin, and Xianjun Sun

Subjects
Materials science, Transmission (telecommunications), business.industry, Broadband, Physics::Optics, General Physics and Astronomy, Optoelectronics, Metamaterial, Astrophysics::Cosmology and Extragalactic Astrophysics, business, Absorption (electromagnetic radiation), Microwave
Abstract

To fulfill the antenna system criteria for broadband microwave-absorbing materials, herein, a magnetic medium is introduced into the metamaterial structure design process, which can produce the artificially required transmission properties in the microwave region. The composite meta-structure can effectively provide microwave absorption at low frequency and microwave transmission at high frequency by optimising the design of the metasurface, dielectric and magnetic medium. The magnetic-medium–based metamaterial is fabricated in accordance with the design, and its electromagnetic characteristics are investigated. Experimental results show that the absorptivity of the proposed metamaterial structure is higher than 85% at 2.4–9.8 GHz, and that the transmissivity is higher than 71% at 15.5–18.8 GHz, 19.6–20.5 GHz, and 36–39 GHz. The absorptivity bandwidth exceeding 90% reaches 6.0 GHz, which is significantly higher than the traditional metamaterial without a magnetic medium. Moreover, the electromagnetic characteristics of the composite material are consistent under varying microwave polarisations.

Published
2021

15. Remediation of Pb- and Cd-contaminated clayey soil viamagnetic-enhanced washing

Author

RUI, Dahu, WANG, Yuru, NIE, Wenjun, KIM, Mintae, ZHANG, Jun, WANG, Shuren, ITO, Yuzuru, and NIU, Fujun

Abstract

The mass transfer efficiency between the contaminant and the washing eluent is the fundamental factor that limits the efficiency of chemical washing. In this study, the magnetization technique was employed to improve the physicochemical properties of eluent and cross-tests were conducted on clayey soils samples contaminated with lead (Pb) and cadmium (Cd). Furthermore, eluent concentration, magnetization strength, and magnetization time were varied as parameters for enhancing mass transfer efficiency. Results showed that after magnetization, the viscosity, surface tension, and contact angle of ethylene diamine tetraacetie acid (EDTA) decreased, whereas conductivity and pH increased. In particular, the viscosity of high-concentration EDTA increased with higher magnetic field strength and longer magnetization time. The maximum removal of Cd and Pb increased by 64.46% and 35.49%, respectively, compared with the unmagnetized lysate. This result highlighted the efficient mass transfer and synergistic mechanism of the magnetization technique, facilitating better contact between the eluent and the contaminants. Magnetization eluent has been proven to be an efficient, cost-effective, and easily implementable method for enhancing mass transfer efficiency, providing a valuable reference for improving the efficiency of chemical washing for heavy metal-contaminated clayey soil.

Published
2024
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