Browsing by Author "Shauo, Chang-Neng"

Now showing 1 - 2 of 2

Effect of dispersant on preparation of colloidal magnetite nanocrystals
(2006-07-01)
Shauo, Chang-Neng
;
Chao, Chuen-Guang
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Nanometer scale magnetite particles were prepared in a very low concentration dispersing system with a dispersant. The average size of the particles prepared under optimum conditions was determined by transmission electron microscopy to be approximately 1.8 nm. The magnetic properties were investigated using a superconducting quantum interference device (SQUID) magnetometer. The dried samples exhibited approximately super-paramagnetic behavior. Rhelogical property measurement shows that the colloidal magnetite both with and without polyurethane reveals shear thinning. The surface morphology of the films of the magnetite nanoparticles on the glass, as shown by atomic force microscopy (AFM) images, produces well-formed surface structure's that are evenly spaced by the magnetite nanoparticles. It also shows that this is an effective method of surface modification for nanometer scale magnetite.
Magnetic and optical properties of isolated magnetite nanocrystals
(2007-05-01)
Shauo, Chang-Neng
;
Chao, Chuen-Guang
;
Wu, Tsien Ming
;
Shy, Hsiou-Jeng
;
材料科學與工程學系
Following preparation of isolated nano-sized magnetite particles in a low-concentration dispersant solution, this study investigated the magnetic and optical properties. Magnetic measurements indicated that the magnetite nanoparticles exhibited perfect superparamagnetism above the blocking temperature. Optical measurements revealed that the magnetic films exhibited good transmittance in the visible region and excellent UVB absorption. It has potential for use in optical applications (UVB-cut), such as sunglasses, heat mirror film and others.