The antimicrobial activity of metallic nanoparticles against bacteria was investigated. Silver, copper, and titania nanoparticles were tested. The bacteria species E. coli and B. subtilis were selected as models for Gram-negative and Gram-positive bacteria, respectively. Bacteriological tests were performed in Luria-Bertani (LB) medium or Nutrient (NT) medium on solid agar plates containing different concentrations of nanoparticles in the range of 0 to 150 μg/mL. Silver and copper nanoparticles were shown to be an effective bactericide. However, titania nanoparticles were found to be ineffective as an antimicrobial agent. It appears that E. coli cells are more sensitive to the copper nanoparticles than to silver nanoparticles and B. subtilis cells have similar sensitivity against both copper and silver nanoparticles.

In order to prevent the oxide formation on the surface of nano-size iron particles and thereby to improve the oxidation resistance, iron nanoparticles synthesized by a chemical vapor condensation method were directly soaked in hexadecanethiol solution to coat them with a polymer layer. Oxygen content in the polymer-coated iron nanoparticles was significantly lower than that in air-passivated particles possessing iron-core/oxide-shell structure. Accordingly, oxidation resistance of the polymer-coated particles at an elevated temperature below in air was times higher than that of the air- passivated particles.

The copper oxide nano powders were synthesized by levitational gas condensation(LGC) method, and their high heterogeneous catalytic effects of oxidation of 2,3,5-trimethyl-1,4- hydroquinone (TMHQ) and catalase activity were studied. The observation of transmission electron microscopy (TEM) shows that most of these nano powders are uniform in size, with the average particle size of 35 nm. The nano powder consists of mainly , but it is aged to CuO phase. The catalytic effect which was clarified by oxidation of TMHQ and catalase depends on the amount of cuprite phase and the particle size.

The preparation of CaSO4 nanoparticle by vesicles formed spontaneously in cationic OTAC and anionic ADS mixed surfactant solution whose ratio is 0.3/0.7 is investigated. Added electrolytes for preparing nanoparticles reduce vesicle size about 200-300 nm comparing with that of pure vesicle whose size is 700-800 nm by DLS. The core of vesicles has 200 nm size and acts as nanoreactors which same size of monodisperse CaSO4 nanopaticles are formed. Although CaSO4 particles are formed at the outer of vesicles, they are very large and amorphous. The formed particles are identified with XRD analysis after separation due to coinciding with CaSO4 particles.

FePt nanoparticles for high-density magnetic recording media were synthesized by the simultaneous chemical reduction of Fe(acac) and Pt(acac) with 1,2-hexadecanediol as the reducing reagent. TEM images showed that the shape of as-synthesized FePt nanoparticle was spherical and average particle size was 3 nm. Also, SAD pattern showed that crystal structure was disordered FCC (face centered cubic). These FCC structured nanoparticles were transformed FCT (face centered tetragonal) structure by annealing at 55 for 30 min in Ar atmosphere. XRD analysis revealed that as-synthesized FePt nanoparticles were transformed from disordered FCC to ordered FCT. Finally, the coercivity of 2 kOe for FePt nanoparticles with FCT structure was obtained by VSM measurement.

The nano-sized Co particles were successfully synthesized by chemical vapor condensation (CVC) process using the precursor of cobalt carbonyl (). The influence of carrier gases on the microstructure and magnetic properties of nanoparticles was investigated by means of XRD, TEM, XPS and VSM. The Co nano-particles with different phases and shapes were synthesized with a change of carrier gas : long string morphologies with coexistence of fcc and hcp structure in Ar carrier gas condition; finer Co core in a mass of cobalt oxide with only fcc structure in He; rod type cobalt oxide phase in Ar＋6vol％. The saturation magnetization and coercivity was lower in Co nanoparticles synthesized in He carrier gas, due to their finer size.