Papers by Author: Kwang Jin Kim

Abstract: Layered double hydroxide(LDH) was synthesized from the mixture of magnesium hydroxide and aluminum hydroxide with microwave irradiation. It has been compared with that of conventional heating method in the respect of crystallization time, structure, morphology, particle size, and its anion exchange capacity. The microwave speeded up the crystallization rate of Mg-Al- LDH so that the XRD patterns of LDH was observed from the sample after microwave hydrothermal treatment, while the crystal phase was hardly observed from that prepared by conventional hydrothermal method before drying process. Mg-Al-LDH prepared with microwave irradiation seemed to have slightly higher Mg/Al molar ratio even with the same compositions of starting materials and the lower anion exchange capacity after 1 day exposure in 0.1N NaCl solution compared to the conventionally prepared one.

Abstract: Porous hydroxyapatite coated with mesoporous silica has been utilized as the matrix for controlled drug delivery. TEM observation confirms the pore size of mesoporous silica scatters about 50 Å. Porous hydroxyapatite was coated with mesoporous silica via sol-gel process. Ibuprofen and was loaded into the pores of mesoporous silica, and controlled release profiles were studied by soaking the samples in a simulated body fluid using a UV-VIS spectrophotometer.

Abstract: Magnesium powders having inactive surface layer have been processed easily and intentionally by DET under fluoride, chromate, and bromide salt. The modified surfaces play an important role in preventing contact with active environments to improve corrosion resistance of Magnesium powders; the image of the surface modified powders was observed using SEM. The composition distribution and characteristics was determined and analyzed by using XRD, XPS, and EIS. Compared with bare Magnesium, the Magnesium having chromate modified surface layer showed a more passive behavior such as smaller current density and nobler potential in 4wt% NaCl solution.