Heon Ju Lee

Metallic mirrors are now essential components of the (International Thermonuclear Experiment Reactor) ITER plasma diagnostics system. The optical properties of the first mirror (FM) in the hostile...

In this study, we demonstrate an effective skin therapy device based on the plasma generated nitric oxide (NO) and needling techniques. The NO generator was constructed based on the dielectric barrier discharge plasma and combined with a commercial needling device. As a result, continueous flow of the NO could be supplied during needling treatment procedure. Several input voltages were investigated to generate plasma and study the optimum concentration of the generated NO. Furthermore, the synergetic effect of the NO exposure and needling technique to the collagen generation on the skin was analysed by both histological and gene expression methods on SKH-1 mice. Based on the histological examination, the samples treated with plasma showed an increased subcutaneous collagen density, and this effect was enhanced with a higher depth of needling. The differential gene expression of the Col4a5 gene was increased more than 100 times in the samples treated with a longer exposure of needling and plasma regardless of the depth. The results suggest that both needling and plasma treatment have a synergistic effect on the production of collagen which might be due mainly to the increased expression of the Col4a5 gene in the dorsal skin of SKH-1 mice.

Hierarchical metal–semiconductor nanostructures composed of Ag nanowire and ZnO nanorod branches were prepared by using the galvanic-potential-enhanced hydrothermal method.

Plasma discharge is a novel disinfection and effectual inactivation approach to treat microorganisms in aqueous systems. Inactivation of Gram-negative Escherichia coli (E. coli) by generating high-frequency, high-voltage, oxygen (O₂) injected and hydrogen peroxide (H₂O₂) added discharge in water was achieved. The effect of H₂O₂ dose and oxygen injection rate on electrical characteristics of discharge and E. coli disinfection has been reported. Microbial log reduction dependent on H₂O₂ addition with O₂ injection was observed. The time variation of the inactivation efficiency quantified by the log reduction of the initial E. coli population on the basis of optical density measurement was reported. The analysis of emission spectrum recorded after discharge occurrence illustrated the formation of oxidant species (OH^•, H, and O). Interestingly, the results demonstrated that O₂ injected and H₂O₂ added, underwater plasma discharge had fabulous impact on the E. coli sterilization. The oxygen injection notably reduced the voltage needed for generating breakdown in flowing water and escalated the power of discharge pulses. No impact of hydrogen peroxide addition on breakdown voltage was observed. A significant role of oxidant species in bacterial inactivation also has been identified. Furthermore the E. coli survivability in plasma treated water with oxygen injection and hydrogen peroxide addition drastically reduced to zero. The time course study also showed that the retardant effect on E. coli colony multiplication in plasma treated water was favorable, observed after long time. High-frequency underwater plasma discharge based biological applications is technically relevant and would act as baseline data for the development of novel antibacterial processing strategies.

Photoelectrochemical properties of CuO/ZnO photoelectrodes fabricated with nanorod and film structures were investigated and the effect of surface morphology on their photoelectrochemical performance was discussed in detail.

In this paper, we propose optimal design of experimental setup for isotope separation by laser assisted retardation of condensation method. Optimal parameters for this setup can be found from the optimization criterion based on the transport model for rarefied gas flow dynamics in external laser field specifically tuned for selective excitation of target isotope [J. W. Eerkens, Laser Part. Beams 23, 225–253 (2005)]. Constrains applied by condensation dynamics were also considered. Because product cut and enrichment factor corresponding to the optimal conditions are rather small, isotopes in this setup should be recovered iteratively. Proposed method to calculate optimal parameters of experimental setup can be applied for arbitrary chemical element isotopes separation, where target isotopomer chemical structure should provide its highest efficiency. Optimal design of experimental setup operation is demonstrated on the example of sulfur isotopes separation.