A series of annual tree-ring measurements has been performed in order to reconstruct the radiocarbon concentration variation in the Korean atmosphere from AD 1650 to 1850. The absolute ages of the samples were determined using dendrochronology. Alpha-cellulose extraction was applied to prepare the tree-ring samples for precise 14C measurement. The 14C concentrations of the tree rings were then plotted with the dendrochronological ages and showed that during the period AD 1650–1850, the discrepancy in 14C concentration in the Korean atmosphere from IntCal data is small enough to use IntCal data without any further correction. This is nearly one third of the average offset of the 400 yr from AD 1250 to 1650. One of the probable causes for the regional offset around Korea is the contribution of 14C-depleted CO2 released from the northern Pacific Ocean, where old deep water upwells to the surface. It is likely that the release rate of 14C-depleted CO2 decreased due to the temperature change during the Little Ice Age.

Two new species of litter-inhabiting leptonetid spiders from Korea are described: Leptoneta namkungisp. nov. from Mt. Buyong, Chungcheongbuk-do, and Leptoneta kwangreungensissp. nov. from Kwangreung, Gyeonggi-do.

Determining valid zygosity is a basic and important requirement in a twin study, because misdiagnosing zygosity leads to biased results. The Healthy Twin Study has collected data from adult like-sex twins and their families since 2005. In the study, a questionnaire to determine zygosity was developed comprising four questions; one concerning the degree of resemblance, and three concerning the degree of confusion by the resemblance. Among 2,761 individuals (624 twin pairs) of twin and their families, 406 pairs of twins (mean age 38.3, 63.5% women) with both questionnaire and genotype information were selected to examine the validity of the zygosity questionnaire using 16 short tandem repeat markers. We first determined individual zygosity including undetermined category, and then decided the zygosity of a twin pair using a decision tree. Sensitivity of questionnaire diagnosis was 98.8% for monozygotic (MZ) and 88.9% for dizygotic (DZ) twins, and positive predictive value was 97.2% for MZ and 95.0% for DZ. When we compared correctly and wrongly diagnosed twin pairs, misdiagnosed DZ twins (nine pairs) showed striking similarity in stature or obesity even exceeding that of true MZ twins. Our finding suggests that a parsimonious questionnaire method of diagnosing the zygosity will be useful, and adding physical or physiological measurements to a questionnaire of zygosity diagnosis will either confound the correct diagnosis or reduce the efficiency of the study compared with using questionnaire alone or with introducing genotyping.

New stable isotope and noble gas data obtained from fumarolic and bubbling gases and hot spring waters sampled from Deception Island, Antarctica, were analysed to constrain the geochemical features of the island's active hydrothermal system and magmatism in the Bransfield back-arc basin. The 3He/4He ratios of the gases (< 9.8 × 10-6), which are slightly lower than typical MORB values, suggest that the Deception Island magma was generated in the mantle wedge of a MORB-type source but the signature was influenced by the addition of radiogenic 4He derived from subducted components in the former Phoenix Plate. The N2/He ratios of fumarolic gas are higher than those of typical mantle-derived gases suggesting that N2 was added during decomposition of sediments in the subducting slab. The δ13C values of -5 to -6‰ for CO2 also indicate degassing from a MORB-type mantle source. The H2/Ar- and SiO2 geothermometers indicate that the temperatures in the hydrothermal system below Deception Island range from ~150°C to ~300°C. The δD and δ18O values measured from fumarolic gas and hot spring waters do not indicate any contribution of magmatic water to the samples. The major ionic components and δD-δ18O-δ34S values indicate that hot spring waters are a mixture of local meteoric water and seawater. Mn and SiO2 in spring waters were enriched relative to seawater reflecting water-rock interaction at depth.

To improve the IPD reliability of NAND flash memory, plasma oxidation was introduced as the post-treatment process of ONO (Oxide/Nitride/Oxide) IPD. The LP-CVD SiO2 modified by plasma oxidation showed the excellent electrical properties. e.g., low leakage current, high breakdown voltage etc. By the analysis of Tof-SIMS and XRR, we could observe the several changes of physical characteristics such as the reduction of impurities (H, N etc.), the increase of oxide density, and the improvement of oxide surface roughness. We found out the appropriate treatment condition to be able to densify oxide layer without the addition of ONO Equivalent Oxide Thickness (EOT). The LP-CVD SiO2 prepared by plasma oxidation was used for the ONO IPD of 50nm NAND flash device and also compared with the conventional LP-CVD SiO2 in the aspect of the IPD reliability.

Ion-beam-assisted deposition (IBAD) was used for cathode preparation in organic light-emitting diodes to fabricate dense electrode. Dark spot growth rate was decreased by employing the IBAD process due to a highly packed aluminum structure inhibiting the permeation of H2O and O2. However, undesirable leakage current was generated because energetic particles of Al assisted by Ar+ ion may damage the organic material resulting in reduction of contact resistance. The decrease of contact resistance in the IBAD device may be caused by large contact area, increase of density of states, and Li diffusion to phenyl-substituted poly-p-phenylene vinylene.

For enhancement and stabilization of electron emission, Mo and Co silicides were formed from Mo mono-layer and Ti/Co bi-layers on single crystal silicon FEAs, respectively. Using the slope of Fowler-Nordheim curve and tip radius measured from SEM, the effective work function of Mo and Co silicide FEAs are calculated to be 3.13 eV and 2.56 eV, respectively. Compared with silicon field emitters, Mo and Co silicide exhibited 10 and 34 times higher maximum emission current, 10 V and 46 V higher failure voltage, and 6.1 and 4.8 times lower current fluctuation, respectively. Moreover, the emission currents of the silicide FEAs depending on vacuum level are almost same in the range of 10−9 ∼ 10−6 torr. This result shows that silicide is robust in terms of anode current degradation due to the absorption of air molecules.