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- 저자 : Mohammad Jakir Hossain (검색결과 2 건)
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Design and analysis of a new composite double negative metamaterial for multi-band communication
Mohammad Jakir Hossain,Mohammad Rashed Iqbal Faruque,Mohammad Tariqul Islam 한국물리학회 2017 Current Applied Physics Vol.17 No.7
In this paper, a double C-shaped structure of double negative composite metamaterial is designed and depicts in configurations that can capable in a multi-band microwave frequency band. The design has achieved relative negative permeability, relative negative permittivity and relative negative refractive index. Analysis and comparison were done by using four configurations of composite metamaterial such as horizontal 1 1 array and vertical 1 1 array structures and the horizontal 1 1 and vertical 1 1 unit-cell configurations. Multi-band operating frequencies namely, S-band, C-band and X-band have been achieved using all configurations. The proposed metamaterial size is 1.2 cm 1.2 cm 0.16 cm which includes all geometrical parameters to fit the design inside the substrate area. Computer Simulation Technology (CST) is adopted to investigate this design where an incident electromagnetic wave travelling along the positive z-axis with an E-field polarized along the y-axis. The results of the proposed metamaterial depict multi-band metamaterial response over the frequency span from 1 to 15 GHz. The effective medium ratio of the metamaterial unit-cell is 7.44. Moreover, the results clearly seen that the single-negative and double-negative metamaterial characteristics of the unit-cell and arrays over the multi-band. The dimensions and scattering parameters of the proposed double C-shaped metamaterial are suitable for the S -band, C-band and X-band applications.
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Ali Bumajdad,Mohammad Jakir Hossain Khan 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.102 No.-
In this work, disposable surgical face masks (SFMs) have been utilized as nitrogen (N)-doping agents forcarbon (C) adsorbents through thermal carbonization using K2CO3 as activators. A readily available wildplantbiomass (Cyperus papyrus, CP) was chosen as the raw material for manufacturing the adsorbent. A‘‘green-etching” process was employed to synthesize adsorbents with significant modifications and withoutusing of any chemicals. As observed via characterization analysis, upon mixing SFMs with CP at a 1:1weight ratio, there were considerable developments in the specific surface area (SBET = 830 m2/g) for bothmicro- (0.333 cm3/g) and mesopores (0.053 cm3/g) as well as diversified functional groups (e.g., aminoand carbonyl) on the sorbent that was produced. This is a key for the adsorbent’s ability in order toremove a variety of pollutants from aqueous solutions. The heavy metal (Cr(VI)) ion adsorption capacitywas used to identify the optimum adsorption parameters. Significantly lower amounts of Cr(VI) residueswere achieved at a concentration of 2 mg/L from an initial Cr(VI) concentration of 30 mg/L by applying anSFM-modified sorbent dose of 10 g/L. The outcomes of this research could be advantageous for decisionmaking in plastic waste management that surged during the COVID-19 pandemic.
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