전동렬 교수

Enormously high secondary electron emission yields under electric field are observed from MgO deposited on carbon nanotubes. The yields reach a value as high as 15 000 and are strongly dependent upon the bias voltage applied to the sample. The creation of the electric field across the MgO film after bombardment of primary electrons is considered as one of key features, since positive charges are generated at the surface by departure of secondary electrons. Subsequent bombarding electrons produce

The absolute coverage of K on the Si(111)-3×1-K surface which was prepared by deposition of K on the 420°C Si substrate was determined, by using coaxial impact-collision ion scattering spectroscopy, to be 0.29±0.03ML. This result rules out the possibility that the 3×1-K phase is formed by K impurity stabilization claimed by several groups. Another important implication of this result is that K atoms of the 3×1 overlayer are not imaged bright in the STM.

The structure of the Na-induced Si(111) 3×1 surface has been studied using a field-ion-scanning-tunneling-microscope. The STM images showed that the entire Si surface was uniformly covered with a single layer of atomically resolved Na 3×1 structure. Upon annealing, the Na layer peeled off gradually, revealing the underlying Si substrate, which exhibited various intermediate reconstructions such as 2×2, 5×5, and 9×9 before the 7×7 structure was restored at 800°C. Our observations suggest that the

The surface structure and the insulator-metal transition of the Na overlayer on the Na-induced Si(111)3×1 surface was studied using scanning tunneling microscopy and spectroscopy. The results suggested that this reconstruction was caused by the conversion of the 7×7 structure to the bulk-terminated 1×1 structure and a monolayer of Na adatoms arranged in the 3×1 periodicity at a coverage of 2/3 monolayer. When oxygen was adsorbed on this surface the surface morphology hardly changed up to several

The usual way of fabricating bottom-contact pentacene field effect transistors (FETs) is to vacuum-evaporate pentacene molecules onto a substrate with patterned electrodes. We observed that the heights of the source and the drain electrodes affected the drain current of a pentacene FET made in this way. Atomic force microscopy measurements of the patterned substrate coated with pentacene revealed a region in the channel where pentacene did not adsorb along the electrodes edge. This pentacene-den

Using spectroscopic ellipsometry as a surface plasmon resonance (SPR) detector, we studied the antibody-antigen interaction of the Her-2/neu protein from SKBR3 breast cancer cells. Chips were prepared by immobilizing the HER2 antibody on a linker-coated Au surface and the SPR was measured after dipping the chip in SKBR3 buffer and drying. The shifts of the SPR peak at each step of the chip preparation and the corresponding morphology change in the atomic force microscopy images suggested that th

The local charge of plasmid DNA has been studied using electrostatic force microscopy (EFM). The sample was prepared by immersing plasmid DNA in ZnCl2. The interaction of the tip with the positive local charge was stronger for the DNA immersed in a solution of higher concentration, and this phenomenon was evidence of the positive metallic ion intercalation into DNA.

Too much competition in the university entrance examination in Korea is disturbing a normal educational system. In my opinion, the reason for the irrational competition is rooted not only in the competition to secure better future through higher education but also the lack of fairness and greed of the individual. The government has been trying to ease the situation without any success. Not only that the government policy is too much lean toward the objectiveness of an entrance examination test t