41 巻 (2004) 6 号 p. 424-430
Generator for charged nanodroplets with sonic-jet ionizer was developed. The size distributions of ions and nanodroplets were measured as well as the electrical currents generated by ions and charged nanodroplets. The sonic-jet ionizer produced O-2(H2O)n ions with high density of 109-1010cm-3. When tetraethylorthosilicate (TEOS) and H2O vapors were added in the oxygen gas, the generator formed negatively charged nanodroplets with average diameter of 1.3-1.8 and 1.3nm, respectively. SiO2 nanoparticles synthesized from the charged TEOS nanodroplets were non-agglomerated. The size distributions measured at various furnace temperatures indicated that the formation mechanism of nanoparticles was ion-induced nucleation. In order to investigate the sterilization effects of negatively charged H2O nanodroplets, yeast fungi were exposed to the gas flow from the charged nanodroplet generator. Survival rates of yeast were clearly reduced by the discharge.