A method for manufacturing terahertz absorber is presented. Varying fractions of graphite powder are mixed with the host poly methylmethacrylate powder and compress molded. The shielding efficiency, together with real and imaginary parts of the dielectric constant, is unambiguously determined by terahertz time domain spectroscopy in the continuous frequency range of 0.1–1.6THz. While the composites are absorptive in most of the frequency range with relatively small reflection, it turns metallic at a high enough graphite fraction of 35.7%: there exists a zero crossing of the real part of dielectric function εr(ω) to negative values below 0.22THz. Our method provides an easy-to-control way of manufacturing terahertz absorbers with a wide range of shielding efficiency and low reflectance.

We fabricated Exfoliated Graphite (EG) anodes that are modified with different amounts of Multiwall Carbon Nanotube (MWCNT), and the effect of the MWCNT amount contained in the anode on the performance of Microbial Fuel Cells (MFCs) is examined. The MWCNT mixed with EG wraps the surface of EG planes consisting of the anode, and it enhances the electrochemical activities of the anode. The MWCNT on the anode surface catalyzes extracellular electron transfer to the anode, and it increases electrical conductivity of the anode by bridging the EG planes. The maximum power density of the MFC is increased with the increasing amount of the MWCNT in the EG anode. The power density of MFC with EG anode containing the MWCNT of 67% was 1,444 mW/m 2 , which is 140% higher than that of the control. The composite anode of EG and MWCNT is recommended as a good alternative for high performance MFCs.