Aims:  Escherichia coli and Bacillus subtilis spores were treated with an atmospheric plasma mixture created by the ionization of helium and oxygen to investigate the inactivation efficiency of a low‐temperature plasma below 70°C. Methods and results:  An electrical discharge plasma was produced at a radio frequency (RF) of 13·56 MHz, connected to a perforated circular electrode with a discharge spacing of 1–15 mm. The discharge gas was helium with 0–2% oxygen. For the plasma treatment, a dried E. coli cell or B. subtilis endospore suspension on a cover‐glass was exposed to oxygen downstream of the plasma from holes in an RF‐powered electrode. The sterilization effect of the RF plasma was highest with 0·2% oxygen, corresponding to the maximum production of oxygen radicals. Conclusions:  Oxygen radicals generated by RF plasma are effective for the destruction of bacterial cells and endospores. Significance and Impact of the study:  Low‐temperature atmospheric plasma can be used for the disinfection of diverse objects, especially for the inactivation of bacterial endospores.

In this paper, the electrical discharge characteristics of plasmas generated in coaxial cylindrical electrodes capacitively powered by a radio-frequency power supply at atmospheric pressure are investigated with respect to helium and argon gases. The electrical discharge parameters, voltage ͑V͒, current ͑I͒, and power ͑P͒, are measured for both helium and argon plasmas, and the electron temperatures and electron densities for them are evaluated by means of the equivalent circuit model and the power balance equation. By comparison of the discharge characteristics of the helium and argon plasmas, it is found that the discrepant macroscopic characteristics of helium and argon plasma, viz., current and voltage characteristics and current and power characteristics, are owed to their own intrinsic microscopic parameters of the helium and argon atoms, such as the first excited energy, the ionization energy, the total cross section, and the atom mass. Furthermore, the influences of the additive gas, oxygen gas, on the electrical discharge characteristics are also investigated in the helium and argon plasmas, which are closely related to the electron temperature of plasmas.

No abstract

We synthesized mesoporous hollow carbon on a graphene surface (MHCG). When applied into supercapacitor electrode, MHCG electrode exhibited outstanding maintenance of energy density above 30 W h kg−1 even under 1 kW kg−1 power density.

We report on the first synthesis of porous ZrO2-SiO2 sheets with well-defined ultrasmall WO3 nanoparticles for energy storage performance. In our system, for improving the surface deterioration of electrode, we use the ZrO2-SiO2 sheets using graphene oxide as a template to access electrode substrate. The synthesized electrode with about 20 nm thickness and about 10 nm pores, has a maximum value of 313 F/g at current density of 1 A/g and a minimum value of 160 F/g at current density of 30 A/g in the specific capacitance. In addition, over 90% of its initial specific capacitance is retained when they are cycled up to 2500 cycles.

Surfactant-free bimetallic Au@Pd core-shell NPs on graphene sheets were fabricated from Au, Pd ions and graphene oxide by one-step reduction using ascorbic acid as an eco-friendly reducing agent. Au@Pd NPs with about 7 nm size are evenly distributed on the surface of graphene. The core/shell structures were confirmed with X-ray diffraction (XRD) and High-angle annual dark field scanning transmission microscopy (HAADF-STEM) mapping analysis. Prepared Au@Pd/graphene nanocomposites show an excellent electrocatalytic activity toward ethanol oxidation: I f value that was the best for our catalysts is 11.6 A mg 21 , which is about 5 times as high as that of the previous catalyst. The data resulted from extremely optimized bimetallic structure of a small Au core and a thin Pd shell. Pd atoms are constantly encouraged by adjacent Au atoms.

No abstract

No abstract