Papers by Author: Gan Moog Chow

Abstract: We successfully synthesized near infrared (NIR) sensitive Au(shell)-Au2S(core) nanoparticles, where Au2S dielectric core was encapsulated by a thin gold shell. The cytotoxicity in vitro and biodistribution in vivo of Au-Au2S nanoparticles was studied by using NIH3T3 cells and KM mice, respectively. The quantitative analysis of Au in each tissue of mice was done by using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Au-Au2S nanoparticles (< 300 μg/ml) showed good biocompatibility. Au-Au2S nanoparticles were preferentially taken up by the liver and spleen, and ultimately eliminated mostly in the feces.

Abstract: The elemental magnetic moments of Co and Cr in CoCrPt films were investigated using xray magnetic circular dichroism (XMCD). The spin and orbital moments of Co was calculated using the sum rules; it was found that the magnetic moment of Co in CoCrPt films was dominated by spin moment contribution. The total magnetic moment of Co was found to be lower than that of bulk Co. Further, the Cr moment was aligned anti-ferromagnetically with respect to Co, resulting in a decrease of saturation magnetization (Ms) in CoCrPt films.

Abstract: The surface composition of nanoparticles is generally different from the average or bulk composition; this phenomenon is commonly referred to as surface segregation. In the present work, the surface segregation in Au-Ti nanoparticles has been analyzed based on a thermodynamic model that incorporates the size effect into the quasichemical model. The calculated surface compositions of Au-Ti nanoparticles are compared with that of the bulk Au-Ti alloys.

Abstract: An analysis of surface segregation of Au-Ti alloy nanoparticle (atomic ratio 1:1) is carried out using Monte Carlo simulation with the energetics described by Bozzolo-Ferrante-Smith method. The surface compositions of Au in Au-Ti nanoparticles are calculated based on the simulation that takes into account the size effect. The segregated surface compositions of Au in the Au-Ti binary alloy single-crystal nanoparticles (with particle diameter of 10-100 nm) are observed to be larger than that of the corresponding bulk single crystal (with the particle diameter > 100 nm). The details of Monte Carlo simulation and the calculated surface compositions due to segregation are discussed.