• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.303-310
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• 2008

We fabricated hydrogenated amorphous silicon(a-Si:H) 140 nm thick film on a $180\;nm-SiO_2/Si$ substrate with an inductively-coupled plasma chemical vapor deposition(ICP-CVD) equipment at $250^{\circ}C$. Moreover, 30 nm-Ni film was deposited with a thermal-evaporator sequently. Then the film stack was annealed to induce silicides by a rapid thermal annealer(RTA) at $200{\sim}500^{\circ}C$ in every $50^{\circ}C$ for 30 minuets. We employed a four-point tester, high resolution X-ray diffraction(HRXRD), field emission scanning electron microscope(FE-SEM), transmission electron microscope(TEM), and scanning probe microscope(SPM) in order to examine the sheet resistance, phase transformation, in-plane microstructure, cross-sectional microstructure evolution, and surface roughness, respectively. We confirmed that nano-thick high resistive $Ni_3Si$, mid-resistive $Ni_2Si$, and low resistive NiSi phases were stable at the temperature of <300, $350{\sim}450^{\circ}C$, and >$450^{\circ}C$, respectively. Through SPM analysis, we confirmed the surface roughness of nickel silicide was below 12 nm, which implied that it was superior over employing the glass and polymer substrates.

• Journal of Korea Water Resources Association
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• v.42 no.2
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• pp.149-160
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• 2009

The objective of this study is to suggest parameter regionalization scheme which is integrated two multivariate statistical methods: principal components analysis(PCA) and hierarchical cluster analysis(HCA). This technique is to apply semi-distributed rainfall-runoff model on ungauged catchments. 7 catchment characteristics (area, mean altitude, mean slope, ratio of forest, water content at saturation, field capacity and wilting point) are estimated for 109 mid-sized sub-basins. The first two components from PCA results account for 82.11% of the total variance in the dataset. Component 1 is related to the location of the catchments relevant to the altitude and Component 2 is connected with the area of these. 103 ungauged catchments are clustered using HCA as the following 6 groups: Goesan 23, Andong 6, Imha 5, Hapcheon 21, Yongdam 4, Seomjin 44. SWAT model is used to simulate runoff and the parameters of the model on the 6 gauged basins are estimated. The model parameters were regionalized for Soyang, Chungju and Daecheong dam basins which are assumed as ungauged ones. The model efficiency coefficients of the simulated inflows for these three dams were at least 0.8. These results also mean that goodness of fit is high to the observed inflows. This research will contribute to estimate and analyze hydrologic components on the ungauged catchments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.76-83
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• 1985

A hypothesis that artificial reforming of corn canopy could improve solar light penetration and dry matter production was tested in corn fields (var. Suwon 19) with three planting densities; low (60 ${\times}$ 40cm), medium (60 ${\times}$ 24cm) and high (60 ${\times}$ 16cm). Natural canopy was found that leaf orientations were even over all azimuth but somewhat inclined toward north-south direction and leaf angle ranged 38$^{\circ}$ to 71$^{\circ}$ from horizontal surface. Reforming corn canopy included following treatments: 1) natural canopy planted in north-south rows (natural canopy), 2)east-west plane canopy planted in north-south rows (E-W canopy), 3)east-west plane canopy and upright leaves in north-south rows, 4)north-south plane canopy (N-S canopy) in east-west rows. After corn plots were installed with training system by supporting poles and connecting wires, corn leaves were induced to a reforming direction and tied on wire. Average light intensity at the mid-point of plant height showed 5-10% increases in E-W canopy and in E-W canopy plus upright leaves, but a 2-10% decrease in N-S canopy from natural canopy. At yellow ripe stage, total dry wt. was increased in E-W canopy but not in N-S canopy. The E-W canopy produced 3-10% more grain yield than natural canopy. Though E-W canopy plus upright leaves yielded less at low density, it yielded up to 10% more at higher density. The N-S canopy yielded similar to low compared with natural canopy. These results suggests that reforming canopy toward solar incident direction increases light penetration into lower canopy, photosynthetic efficiency and grain yield, especially at high planting density in corn.

• Journal of Hospice and Palliative Care
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• v.15 no.4
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• pp.205-211
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• 2012

Purpose: This study was performed to identify the level of stress perceived by nurses who attend dying patients in the cancer care unit; their understanding regarding end-of-life care and related training needs. Methods: A cross-sectional descriptive study was conducted with 151 nurses stationed at the cancer care units of four general hospitals located in Seoul and Gyeonggi province in Korea. Data were collected using self-reported questionnaires and the response rate was 96%. The data were analyzed using t-test, ANOVA and Pearson's correlation analysis. SPSS 12.0 was used for data analysis. Results: Nurses experienced a high level of stress in the end-of-life care settings. Their understanding of end-of-life care was above the mid-point of the scale while their training needs for end-of-life care was relatively high. The more experienced the nurses were, the more stressed they were, particularly due to excessive workload. Nurses who served longer in the cancer unit tended to show greater needs for end-of-life care training. Conclusion: This study found nurses perform end-of-life care with a high level of stress but with insufficient understanding, and thus, showed great needs for related training. Such findings can be useful to develop an end-of-life care training program for nurses.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.5
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• pp.109-115
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• 2016

A demand of high bearing capacity of piles to resist heavy static loads has been increased. For this reason, the utilization of large diameter PHC piles including a range from 700 mm to 1,200 mm have been increased and applied to the construction sites in Korea recently. In this study, in order to increase the flexural strength capacity of the PHC pile, the large diameter composite PHC pile reinforced by in-filled concrete and reinforcement was developed and manufactured. All the specimens were tested under four-point bending setup and displacement control. From the strain behavior of transverse bar, it was found that the presence of transverse bar was effective against crack propagation and controlling crack width as well as prevented the web shear cracks. The flexural strength and mid-span deflection of LICPT specimens were increased by a maximum of 1.08 times and 1.19 times compared to the LICP specimens. This results indicated that the installed transverse bar is in an advantageous ductility performance of the PHC piles. A conventional layered sectional analysis for the pile specimens was performed to investigate the flexural strength according to the each used material. The calculated bending moment of conventional PHC pile and composite PHC pile, which was determined by P-M interaction curve, showed a safety factor 1.13 and 1.16 compared to the test results.

• Journal of the Korean GEO-environmental Society
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• v.16 no.12
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• pp.23-35
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• 2015

Nonlinear soil behavior before failure under dynamic loading is often implemented in a numerical analysis code by a mathematical fitting function model with Masing's rule. However, the model may show different behavior with an experimental results obtained from laboratory test in damping ratio corresponding secant shear modulus for a certain shear strain rage. The difference may come from an unique soil characteristics which is unable to implement by using the existing mathematical fitting model. As of now, several fitting models have been suggested to overcome the difference between model and real soil behavior but consequence of the difference in dynamic analysis is not reviewed yet. In this paper, the effect of the difference on site response was examined through nonlinear response history analysis. The analysis was verified and calibrated with well defined dynamic geotechnical centrifuge test. Site response analyses were performed with three mathematical fitting function models and compared with the centrifuge test results in prototype scale. The errors on peak ground acceleration between analysis and experiment getting increased as increasing the intensity of the input motion. In practical point of view, the analysis results of accuracy with the fitting model is not significant in low to mid input motion intensity.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.3
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• pp.144-150
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• 2016

Objectives: We compared the transbuccal and transoral approaches in the management of mandibular angle fractures. Materials and Methods: Sixty patients with mandibular angle fractures were randomly divided into two equal groups (A, transoral approach; group B, transbuccal approach) who received fracture reduction using a single 2.5 mm 4 holed miniplate with a bar using either of the two approaches. Intraoperatively, the surgical time and the ease of surgical assess for fixation were noted. Patients were followed at 1 week, 3 months, and 6 months postoperatively and evaluated clinically for post-surgical complications like scarring, infection, postoperative occlusal discrepancy, malunion, and non-union. Radiographically, the interpretation of fracture reduction was also performed by studying the fracture gap following reduction using orthopantomogram tracing. The data was tabulated and subjected to statistical analysis. A P -value less than 0.05 was considered significant. Results: No significant difference was seen between the two groups for variables like surgical time and ease of fixation. Radiographic interpretation of fracture reduction revealed statistical significance for group B from points B to D as compared to group A. No cases of malunion/non-union were noted. A single case of hypertrophic scar formation was noted in group B at 6 months postsurgery. Infection was noted in 2 patients in group B compared to 6 patients in group A. There was significantly more occlusal discrepancy in group A compared to group B at 1 week postoperatively, but no long standing discrepancy was noted in either group at the 6 months follow-up. Conclusion: The transbuccal approach was superior to the transoral approach with regard to radiographic reduction of the fracture gap, inconspicuous external scarring, and fewer postoperative complications. We preferred the transbuccal approach due to ease of use, minimal requirement for plate bending, and facilitation of plate placement in the neutral mid-point area of the mandible.

• Journal of Periodontal and Implant Science
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• v.31 no.4
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• pp.787-801
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• 2001

The molecular mechanisms control the function of PDL(periodonta1 ligament) cells and/or fibroblasts remain unclear. PDLsl7, PDL-specific gene, had previousely　identified the cDNA for a novel protein from cultured　PDL fibroblasts using subtraction hybridization between gingival fibroblasts and　PDL fibroblasts. The purpose　of this study was to determine the regulation by growth factors and cytokines on　PDLsl7 gene expression in　cultured human periodontal ligament cells and observe the immunohistochemical　localization of PDLsl7 protein in various tissues of mouse. Primary PDL fibroblasts isolated by scraping the root of the extracted human mandibular third molars. The cells were incubated with various concentration of human recombinant $IL-1{\beta}$, PDGF-BB and TGF\;${\beta}$ for 48h nd 2 weeks. At each time point total RNA was extracted and the levels of transcription ere assessed by reverse transcription-polymerase chain reaction (RT-PCR assay). polyclonal antiserum raised against PDLsl7 peptides, CLSVSYNRSYQINE and SEAVHETDLHDGC, were made, and stained the tooth, periodontium, developing bone, bone marrow and mid-palatal suture of the mouse. The results were as follows. 1. PDLsl7 mRNA levels were increased in response to PDGF (10ng/ml) and $TGF\;{\beta}$(20ng/ml) after treatment of the $IL-1{\beta}$, PDGF-BB and $TGF{\beta}$for 48 h. 2. PDLsl7 was up-regulated only by $TGF{\beta}$(20 ng/ml) after treatment of the $IL-1{\beta}$, PDGF-BB and $TGF\;{\beta}$ for 2 weeks and unchanged by the other stimulants. 3. PDLsl7 was a novel protein coding the 142 amino acid peptides in the ORF and the nucleotide sequences of the obtained cDNA from RT-PCR was exactly same as the nucleotides of the database. 4. Immunohistochemical analysis showed that PDLsl7 is preferentially expressed in the PDL, differentiating osteoblast-like cells and stromal cells of the bone marrow in the adult mouse. 5. The expression of PDLsl7 protein was barely detectable in gingival fibroblasts, hematopoetic cells of the bone marrow and mature osteocytes of the alveolar bone. These results suggest that PDLsl7 might upregulated by PDGF-BB or $TGF{\beta}$ and acts at the initial stage of differentiation when the undifferentiated mesenchymal cells in the bone marrow and PDL differentiate into multiple cell types. However, more research needs to be performed to gain a better understanding of the exact function of PDLsl7 during the differentiation of bone marrow mesenchymal and PDL cells.

• Journal of Periodontal and Implant Science
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• v.39 no.2
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• pp.111-118
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• 2009

Purpose: The integrity of interproximal hard/soft tissue has been widely accepted as the key determinant for success or degree of root coverage following the connective tissue graft. However, we reason that the gingival biotype of an individual, defined as the distance from the interproximal papilla to gingiva margin, may be the key determinant that influence the extent of root coverage regardless of traditional classification of gingival recession. Hence, the present study was performed with an aim to verify that individual gingival scalloping pattern inherent from biotype influence the level of gingival margin following the connective tissue graft for root coverage. Methods: Test group consisted of 43 single-rooted teeth from 21 patients (5 male and 16 female patients, mean age: 36.6 years) with varying degrees of gingival recession requiring connective tissue graft; 20 teeth of Miller class I and 23 teeth of Miller class III gingival recession, respectively. The control group consisted of contralateral teeth which did not demonstrate apparent gingival recession, and thus not requiring root coverage. For a biotype determination, an imaginary line connecting two adjacent papillae of a test tooth was drawn. The distance from this line to gingival margin at mid-buccal point and this distance (P-M distance) was designated as "gingival biotype" for a given individual. The distance was measured at baseline and 3 to 6 months examinations postoperatively both in test and control groups. The differences in the distance between Miller class I and III were subject to statistical analysis by using Student.s t-test while those between the test and control groups within a given patient were by using paired t-test. Results: The P-M distance at 3 to 6 months postoperatively was not significantly different between Miller class I and Miller class III. It was not significantly different between the test and control group in a given patient, either, both in Miller class I and III. Conclusions: The amount of root coverage following the connective tissue graft was not dependent on Miller's classification, but rather was dependent on P-M distance, strongly implying that the gingival biotype of a given patient may play a critical impact on the level of gingival margin following connective tissue graft.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.696-706
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• 2003

The purpose of this study was to clarify the palatal forms through palatal curvatures of right to left, anterior to posterior direction, and difference of right and left palatal volumes in the primary and permanent dentition. Samples were consisted of normal occlusion of both dentition(50 males and 50 females each). Their upper plaster casts were used, measuring points were decided, through 3-dimensional laser scanning(3-D Laser Scanner, DS4060, LDI, U.S.A.), and fitting standard horizontal plane were made for measuring the height and sectioned volumes of palate. The results were as follows: 1. Palatal volume and height were greater at the right side of the palate in the primary and permanent dentition of male and female, but there was no significance. 2. Palatal height was greater in male compared to female, especially, there was significant difference at intercuspid, inter-second premolar area in the permanent dentition(P<0.05). 3. To the height of A-P direction of mid-palatal area, the highest point was 20mm in the primary dentition, 30mm in the permanent dentition from interdental papilla of central incisors. 4. Palatal height of inter-cuspid and inter-second premolar became shallow and broad, high and broad each, compared to inter-deciduous canine and inter-second deciduous molar.