• Journal of the korean academy of Pediatric Dentistry
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• v.8 no.1
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• pp.77-88
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• 1981

The purpose of this study was to make a comprehensive study & evaluation of the oral status of mental retarded children. The auther examined intraorally 486 (male; 311, female;175) mental retarded children. The result was as follows; (General mental retarded children means the children who live in their parent's home, & orphan mental retarded children means the children who live in orphanage.) 1. The dft rate was 31.6% in general mental retarded children (G.m.r.c.) & 20.7% in orphan mental retarded children (O. m. r. c.). The dft index was 3.73 in G.m.r.c. & 2.15 in O.m.r.c. 2. The DMFT rate was 24.6% in female G.m.r.c., 16.7% in male G.m.r.c., 12.7% in female O.m.r.c., 8.4% in male O.m.r.c. The DMFT index was 4.94 in female G.m.r.c., 4.01 in male G.m.r.c., 1.40 in male O.m.r.c., 2.75 in female O.m.r.c. 3. The malocclusion prevalence was 57.3%. the class I malocclusion was 14.2% Class II malocclusion 19.3%, Class III malocclusion 23.5%. The children with Down's syndrome had 60.0% of class III malocclusion prevalence. 4. The dental calculus index was 1.97 in male O.m.r.c., 1.81 in female O.m.r.c., 1.30 in male G.m.r.e., 1.13 in female G.m.r.c. 5. The dental plaque index was 3.06 in female G.m.r.c., 3.00 in male Gm.r.e. 2.70 in male O.m.r,c., 2.32 in female O.m.r.c.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.155-156
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• 2006

Single crystalline ZnO fims were successfully grown on r-plane sapphire substrate by plasma-assisted molecular beam epitaxy. Epitaxial relationship between the ZnO film and the-r-plane sapphire was determined to be [-1101]$Al_2O_3\;{\parallel}$ [0001]ZnO, [11-20]$Al_2O_3\;{\parallel}$ [-1100]ZnO based on the in-situ RHEED analysis and confirmed again by HRXRD measurements. Grown (11-20) ZnO films showed faceted structure along the <0001> direction and the RMS roughness was about 4 nm.

• Korean Journal of Materials Research
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• v.2 no.1
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• pp.76-82
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• 1992

Deposition of $TEOS-O_3$ oxide film as inter-metal dielectric layer shows the substrate dependency according to the substrate material and pattern density and pitch size. To minimize substrate and Pattern dependency, TEOS-base and $SiH_4-base$ Plasma oxide were predeposited as underlying material on the substrate. The substrate dependency of $TEOS-O_3$ oxide film was more significant on TEOS-base plasma oxide than on $SiH_4-base$ plasma oxide. The dependency of $TEOS-O_3$ oxide film was remarkably reduced, or nearly eliminated, by $N_2$plasma treatment on TEOS-base plasma oxide, which appears to be caused by the O-Si-N structure, observed on the the surface of TEOS-base plasma oxide.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.2
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• pp.76-82
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• 2003

The robust stack storage node and sufficient cell capacitance for high performance is indispensable for 90 nm DRAM capacitor. For the first time, we successfully demonstrated MIS capacitor process integration for 90 nm DRAM technology. Novel cell layout and integration technology of 90 nm DRAM capacitor is proposed and developed, and it can be extended to the next generation DRAM. Diamond-shaped OCS with 1.8 um stack height is newly developed for large capacitor area with better stability. Furthermore, the novel $Al_2O_3/HfO_2$ dielectric material with equivalent oxide thickness (EOT) of 25 ${\AA}$ is adopted for obtaining sufficient cell capacitance. The reliable cell capacitance and leakage current of MIS capacitor is obtained with ~26 fF/cell and < 1 fA/ceil by $Al_2O_3/HfO_2$ dielectric material, respectively.

• Journal of Sensor Science and Technology
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• v.24 no.6
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• pp.419-422
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• 2015

Pure and Mo-doped ZnO hollow nanofibers were prepared by single capillary electrospinning and their gas sensing characteristics toward 5 ppm ethanol, trimethylamine (TMA), CO and $H_2$ were investigated. The gas responses and responding kinetics were dependent upon sensing temperature and Mo doping. Mo-doped ZnO hollow nanofibers showed high response to 5 ppm TMA ($R_a/R_g=111.7$, $R_a$: resistance in air, $R_g$: resistance in gas) at $400^{\circ}C$, while the responses of pure ZnO hollow nanofibers was low ($R_a/R_g=47.1$). In addition, the doping of Mo enhanced selectivity toward TMA. The enhancement of gas response and selectivity to TMA by Mo doping to ZnO nanofibers was discussed in relation to the interaction between basic analyte gas and acidic additive materials.

• Clean Technology
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• v.19 no.3
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• pp.300-305
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• 2013

Zinc oxide (ZnO) and reduced graphite oxide (rGO) composites were synthesized and tested as adsorbents for the hydrogen sulfide ($H_2S$) adsorption at mid-to-high (300 to $500^{\circ}C$) temperatures. In order to investigate the critical roles of oxygen containing functional groups, such as hydroxyl, epoxy and carboxyl groups, attached on rGO surface for the $H_2S$ adsorption, various characterization methods (TGA, XRD, FT-IR, SEM and XPS) were conducted. For the reduction process for graphite oxide (GO) to rGO, a microwave irradiation method was used, and it provided a mild reduction environment which can remain substantial amount of oxygen functional groups on rGO surface. Those functional groups were anchoring and holding nano-sized ZnO onto the 2D rGO surface; and it prevented the aggregation effect on the ZnO particles even at high temperature ranges. Therefore, the $H_2S$ adsorption capacity had been increased about 3.5 times than the pure ZnO.

• The KIPS Transactions:PartD
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• v.13D no.4 s.107
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• pp.463-476
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• 2006

R-trees have been traditionally optimized for the I/O performance with the disk page as the tree node. Recently, researchers have proposed cache-conscious variations of R-trees optimized for the CPU cache performance in main memory environments, where the node size is several cache lines wide and more entries are packed in a node by compressing MBR keys. However, because there is a big difference between the node sizes of two types of R-trees, disk-optimized R-trees show poor cache performance while cache-optimized R-trees exhibit poor disk performance. In this paper, we propose a cache and disk optimized R-tree, called the PR-tree (Prefetching R-tree). For the cache performance, the node size of the PR-tree is wider than a cache line, and the prefetch instruction is used to reduce the number of cache misses. For the I/O performance, the nodes of the PR-tree are fitted into one disk page. We represent the detailed analysis of cache misses for range queries, and enumerate all the reasonable in-page leaf and nonleaf node sizes, and heights of in-page trees to figure out tree parameters for best cache and I/O performance. The PR-tree that we propose achieves better cache performance than the disk-optimized R-tree: a factor of 3.5-15.1 improvement for one-by-one insertions, 6.5-15.1 improvement for deletions, 1.3-1.9 improvement for range queries, and 2.7-9.7 improvement for k-nearest neighbor queries. All experimental results do not show notable declines of the I/O performance.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.889-893
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• 2011

The energetics and transition state (TS) structures of the reactions of six substrates, $R_1R_2P$(=O or S)Cl-type where $R_1=R_2$=Me and/or MeO, with ammonia in acetonitrile are theoretically investigated at the level of CPCM-MP2/6-31+G(d) and CPCM-MP2/6-311+G(3df,2p). The degrees of distortion of TS from the ideal trigonal bipyramidal pentacoordinate, ${\Delta}{{\delta}}_{{\neq}b}$ for a backside and ${\Delta}{{\delta}}_{{\neq}f}$ for a frontside attack, are calculated. The results of calculation suggest that the feasibility of a frontside attack for P=S is greater than that for P=O system when the two ligands, $R_1$ and $R_2$, becomes larger. The experimental and calculated results of anilinolyses of $R_1R_2P$(=O or S)Cl-type show the consistent tendencies.

• Journal of the Korean Ceramic Society
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• v.54 no.5
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• pp.400-405
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• 2017

$P_2O_5-ZnO-SiO_2-R_2O$ glasses were synthesized as a sealing material for large scale dye-sensitized solar cells (DSSC). Compositional effects of $P_2O_5$ and ZnO were examined by varying their contents. Their viscosity and glass stability at sintering temperatures of less than $550^{\circ}C$ were examined by flow button test. Glass transition temperature and structural change upon compositional change were investigated. Chemical stability against electrolyte was also examined by immersing the glasses in the electrolyte for 72 h at $85^{\circ}C$.

• Korean Journal of Agricultural Science
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• v.44 no.1
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• pp.104-113
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• 2017

Anthocyanins contained in Rhododendron schlippenbachii (royal azalea) are expressed in a variety of colors and affect flower colors. R. schlippenbachii flowers of seven colors (white, red group: pink, deep pink, red, purple group: light purple, purple, deep purple) were collected from the garden around KT&G building in the college of agriculture and life science. Seven types of anthocyanins [cyanidin 3-O-diglucoside, cyanidin 3-O-arabinoside-5-O-glucoside, cyanidin 3-O-galactoside, peonidin 3-O-arabinoside-5-O-glucoside, cyanidin 3-O-glucoside, cyanidin 3-O-(6"-O-malonyl) arabinoside, cyanidin 3-O-(6"-O-coumaroyl) glucoside] turned out to be from the cyanidin and peonidin series in R. schlippenbachii flowers. Also, seven types of flavonols [azaleatin 3-O-glucoside, azaleatin 3-O-arabinoside, azaleatin 3-O-rhamnoside, quercetin 3-O-galacatoside, quercetin 3-O-glucoside, quercetin 3-O-arabinoside, quercetin 3-O-rhamnoside] were identified in R. schlippenbachii flowers. Total anthocyanin amounts decreased in R. schlippenbachii flowers in the following order: 'deep pink' (8.07) > 'red' (6.37) > 'pink' (5.35) > 'deep purple' (0.78) > 'purple' (0.43) > 'light purple' ($0.22mg{\cdot}g^{-1}$ dry weight, DW) > 'white' (not detected). Total flavonol amounts decreased in the following order: 'pink' (97.78) > 'deep pink' (63.79) > 'deep purple' (61.98) > 'white' (57.58) > 'light purple' (47.06) > 'purple' (46.76) > 'red' ($7.60mg{\cdot}g^{-1}$ dry weight, DW). This study provided the quantitative and qualitative information for the variation of anthocyanin and flavonol compounds in R. schlippenbachii flowers. Furthermore, this information can contribute to the identification of anthocyanin and flavonol compounds in other Rhododendron flowers.