• Imaging Science in Dentistry
• /
• v.44 no.1
• /
• pp.61-65
• /
• 2014

Purpose: This study was performed to evaluate the position of impacted mandibular third molars in different skeletal facial types among a group of Iranian patients. Materials and Methods: A total of 400 mandibular third molars in 200 subjects with different types of facial growth were radiographically investigated for their positions according to their types of facial growth on the basis of the ${\beta}$ angle. The subjects were divided into three groups (class I, II, and III) according to ANB angle, representing the anteroposterior relationship of the maxilla to the mandible. Meanwhile, the subjects were also divided into three groups (long, normal, and short face) according to the angle between the stella-nasion and mandibular plane (SNGoGn angle). ANOVA was used for statistical analysis. Results: The mean ${\beta}$ angle showed no significant difference among class I, II, and III malocclusions (df=2, F=0.669, p=0.513). The same results were also found in short, normal, and long faces (df=1.842, F=2, p=0.160). The mesioangular position was the most frequent one in almost all of the facial growth patterns. Distoangular and horizontal positions of impaction were not found in the subjects with class III and normal faces. In the long facial growth pattern, the frequency of vertical and distoangular positions were not different. Conclusion: In almost all of the skeletal facial types, the mesioangular impaction of the mandibular third molar was the most prevalent position, followed by the horizontal position. In addition, ${\beta}$ angle showed no significant difference in different types of facial growth.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.454-454
• /
• 2014

Silicon microwire array is one of the promising platforms as a means for developing highly efficient solar cells thanks to the enhanced light trapping efficiency. Among the various fabrication methods of microstructures, deep reactive ion etching (DRIE) process has been extensively used in fabrication of high aspect ratio microwire arrays. In this presentation, we show precisely controlled Si microwire arrays by tuning the DRIE process conditions. A periodic microdisk arrays were patterned on 4-inch Si wafer (p-type, $1{\sim}10{\Omega}cm$) using photolithography. After developing the pattern, 150-nm-thick Al was deposited and lifted-off to leave Al microdisk arrays on the starting Si wafer. Periodic Al microdisk arrays (diameter of $2{\mu}m$ and periodic distance of $2{\mu}m$) were used as an etch mask. A DRIE process (Tegal 200) is used for anisotropic deep silicon etching at room temperature. During the process, $SF_6$ and $C_4F_8$ gases were used for the etching and surface passivation, respectively. The length and shape of microwire arrays were controlled by etching time and $SF_6/C_4F_8$ ratio. By adjusting $SF_6/C_4F_8$ gas ratio, the shape of Si microwire can be controlled, resulting in the formation of tapered or vertical microwires. After DRIE process, the residual polymer and etching damage on the surface of the microwires were removed using piranha solution ($H_2SO_4:H_2O_2=4:1$) followed by thermal oxidation ($900^{\circ}C$, 40 min). The oxide layer formed through the thermal oxidation was etched by diluted hydrofluoric acid (1 wt% HF). The surface morphology of a Si microwire arrays was characterized by field-emission scanning electron microscopy (FE-SEM, Hitachi S-4800). Optical reflection measurements were performed over 300~1100 nm wavelengths using a UV-Vis/NIR spectrophotometer (Cary 5000, Agilent) in which a 60 mm integrating sphere (Labsphere) is equipped to account for total light (diffuse and specular) reflected from the samples. The total reflection by the microwire arrays sample was reduced from 20 % to 10 % of the incident light over the visible region when the length of the microwire was increased from $10{\mu}m$ to $30{\mu}m$.

• Ocean and Polar Research
• /
• v.32 no.4
• /
• pp.439-448
• /
• 2010

General consensus on typical vertical profile of dissolved oxygen in the Ulleung Basin is that dissolved oxygen concentration beyond 300 m decreases with increasing depth. However, the results of our observations in 2005 and 2006 revealed three different dissolved oxygen distribution types in the deep layer of the Ulleung Basin. The first type showed oxygen concentration decreasing with increasing depth (Type-1), the second showed oxygen concentration decreasing very sharply near the bottom boundary layer but constant in the bottom adiabatic layer (Type-2), the final was of the oxygen minimum layer above the bottom boundary layer (Type-3). Type-2 was the most common pattern in the Ulleung Basin. Type-1 was most common close to the Japan Basin, including the Ulleung Interplane Gap, while Type-3 was found around Dok do. Oxygen Consumption Rate (OCR) at surface sediment estimated using the dissolved oxygen distribution at the bottom boundary layer was $0.2{\sim}5.8\;mmol{\cdot}m^{-2}d^{-1}$, which coincided with OCR from direct sediment incubation. This implies that organic matter decomposition at surface sediment may play an important role in dissolved oxygen distribution patterns at the bottom boundary layer of the Ulleung Basin.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.2A
• /
• pp.123-130
• /
• 2012

A cooling system is indispensable for the fossil and nuclear power plants which produce electricity by rotating the turbines with hot steam. A cycle of the typical cooling system includes pumping of seawater at the intake pump house, exchange of heat at the condenser, and discharge of hot water to the sea. The cooling type of the nuclear power plants in Korea recently evolves from the conventional surface intake/discharge systems to the submerged intake/discharge systems that minimize effectively an intake temperature rise of the existing plants and that are beneficial to the marine environment by reducing the high temperature region with an intensive dilution due to a high velocity jet and density differential at the mixing zone. It is highly anticipated that the future nuclear power plants in Korea will accommodate the submerged cooling system in credit of supplying the lower temperature water in the summer season. This study investigates the approach flow patterns at the velocity caps and discharge flow patterns from diffusers using the 3-D computational fluid dynamics code of $FLOW-3D^{(R)}$. The approach flow test has been conducted at the velocity caps with and without a cap. The discharge flow from the diffuser was simulated for the single-port diffuser and multi-ports diffuser. The flow characteristics to the velocity cap with a cap demonstrate that fish entrainment can significantly be minimized on account of the low vertical flow component around the cap. The flow pattern around the diffuser is well agreed with the schematic diagram by Jirka and Harleman.

• Archives of Plastic Surgery
• /
• v.36 no.4
• /
• pp.512-515
• /
• 2009

Purpose: Neurofibromatosis(NF) is an autosomal - dominant systemic disease. Up to fifty percent of patients with NF are reported to have concomitant vascular abnormalities. In the resection of a larger NF, the risk of uncontrolled hemorrhage is much higher due to the difficulty of hemostasis of large vessels within the tumor. We ligated the base of the giant NF with a simple loop - shaped ligation before removal of the giant NF in both buttocks. And then we could successfully reduce the amount of hemorrhage during the operation. Methods: A 46 - year - old female patient presented for giant masses of both gluteal area, which has been growing slowly for the last ten years. Each mass was about $30{\times}20cm$ in size. After designing the elliptical resection margin, we tightened the tumor base by using continuous loop - shaped suture ligation(weaving the thread up and down in a loop - shaped pattern, leaving a space of 2 cm between each loop) with a straight needle and prolene 2 - 0. After skin incision, we proceeded the dissection toward the central and inferior side of the mass obliquely while we avoided breaking large vascular sinuses. We resected the tumor in a wedged - shape. Subcutaneous tissue was sutured layer by layer and skin was closed by vertical mattress and interrupted suture. The loop - shaped ligation of the base was removed and compressive dressing was done with gauzes and elastic bandages. Results: Postoperative complications such as infection, hemorrhage, hematoma, and dehiscense did not occur. Perioperatively the patient was sufficiently transfused with five units of blood and two units of fresh frozen plasma. During the subsequent 1 year follow - up, the functional and cosmetic result was excellent. Conclusion: A continuous loop - shaped suture ligation procedure along the base of the giant NF effectively reduced the amount of hemorrhage during the operation, made dissection and ligation of vessels easily and quickly, and shorten the operating time and postoperative recovery time.

• Korean Journal of Remote Sensing
• /
• v.31 no.5
• /
• pp.409-419
• /
• 2015

The Atmospheric Emitted Radiance Interferometer (AERI) which is the Fourier Transform InfraRed (FTIR) spectrometer has been operated by the National Institute of Meteorological Research (NIMR) in Anmyeon island, South Korea since June 2010. The ground-based AERI with similar hyper-spectral infrared sensor to satellite could be an alternative way to validate satellite-based remote sensing. In this regard, the NIMR has focused on the improvement of Cloud data Filtering Method (CFM) which employed only one reference spectrum of clear sky in winter season. This study suggests Seasonal-Cloud data Filtering Method (S-CFM) which applied seasonal AERI reference spectra. For the comparison of applied S-CFM and CFM, the methane retrievals (surface volume mixing ratio) from AERI spectra are used. The quality of AERI methane retrieval applied S-CFM was significantly more improved than that of CFM. The positive result of S-CFM is similar pattern with the seasonal variation of methane from ground-based in-situ measurement, even if the summer season's methane is retrieved over-estimation. In addition, the comparison of vertical total column of methane from AERI and GOSAT shows good result except for the summer season.

• Korean Journal of Remote Sensing
• /
• v.27 no.3
• /
• pp.235-258
• /
• 2011

The purpose of this study is to investigate climatological variations from the temporal and spatial surface particulate organic carbon (POC) estimates based on SeaWiFS spectral radiance, and to determine the physical mechanisms that affect the distribution of pac in the Gulf of Mexico. 7-year monthly mean values of surface pac concentration (Sept. 1997 - Dec. 2004) were estimated from Maximum Normalized Difference Carbon Index (MNDCI) algorithm using SeaWiFS data. Synchronous 7-year monthly mean values of remote sensing data (sea surface temperature (SST), sea surface wind (SSW), sea surface height anomaly (SSHA), precipitation rate (PR)) and recorded river discharge data were used to determine physical forcing factors. The spatial pattern of POC was related to one or more factors such as river runoff, wind-derived current, and stratification of the water column, the energetic Loop Current/Eddies, and buoyancy forcing. The observed seasonal change in the POC plume's response to wind speed in the western delta region resulted from seasonal changes in the upper ocean stratification. During late spring and summer, the low-density river water is heated rapidly at the surface by incoming solar radiation. This lowers the density of the fresh-water plume and increases the near-surface stratification of the water column. In the absence of significant wind forcing, the plume undergoes buoyant spreading and the sediment is maintained at the surface by the shallow pycnocline. However, when the wind speed increases substantially, wind-wave action increases vertical motion, reducing stratification, and the sediment were mixed downward rather than spreading laterally. Maximum particle concentrations over the outer shelf and the upper slope during lower runoff seasons were related to the Loop Current/eddies and buoyancy forcing. Inter-annual differences of POC concentration were related to ENSO cycles. During the El Nino events (1997-1998 and 2002-2004), the higher pac concentrations existed and were related to high runoffs in the eastern Gulf of Mexico, but the opposite conditions in the western Gulf of Mexico. During La Nina conditions (1999-2001), low Poe concentration was related to normal or low river discharge, and low PM/nutrient waters in the eastern Gulf of Mexico, but the opposite conditions in the western Gulf of Mexico.

• Korean Journal of Applied Biomechanics
• /
• v.26 no.1
• /
• pp.115-126
• /
• 2016

Objective: The purpose of this study was to investigate plantar foot pressure and static balance according to the type of insole in the elderly. Methods: Thirteen elderly (mean age: $67.08{\pm}2.25years$, mean height: $159.63{\pm}9.64cm$, mean body weight: $61.48{\pm}9.06kg$) who had no previous injury experience in the lower limbs and a normal gait pattern participated in this study. Three models of insoles of the normal, 3D, and triangle types were selected for the test. The Pedar-X system and Pedar-X insoles, 3.3 km/h of walking speed, and a compilation of 20 steps walking stages were used to analyze foot-pressure distribution. Static balance test was conducted using Gaitview AFA-50, and balance (opening eyes, closing eyes) was inspected for 20 s. One-way ANOVA was conducted to test the significance of the results with the three insoles. p-value of less than .05 was considered statistically significant. Results: The mean foot pressure under the forefoot regions was the lowest with the 3D insole during treadmill walking (p<.05). The mean value under the midfoot was the highest with the 3D insole (left: p<.05, right: p<.01). The mean value under the rearfoot was the lowest with the 3D insole (p<.001). The maximum foot pressure value under the foot regions was the lowest on both sides of the forefoot with the 3D insole. A statistically significant difference was seen only in the left foot (p<.01). The maximum value under the midfoot was the highest with the 3D insole (p<.001). No statistically significant difference was detected on the values under the rearfoot. In the case of vertical ground reaction force (GRF), statistically significant difference was seen only in the left side rearfoot (p<.01). However, static balance values (ENV, REC, RMS, Total Length, Sway velocity, and Length/ENV) did not show significant differences by the type of insole. Conclusion: These results show that functional insoles can decrease plantar pressure and GRF under the forefoot and rearfoot. Moreover, functional insoles can dislodge the overload of the rearfoot and forefoot to the midfoot. However, functional insoles do not affect the static balance in the elderly.

• Journal of Wetlands Research
• /
• v.14 no.2
• /
• pp.211-221
• /
• 2012

The ascidian Styela clava has been one of the favorite seafood in Korea. Suspended culture of Styela clava was initiated in 2001 and the annual production reached 15,084 M/T, but declined to 2,655 M/T in 2011. In order to solve this problem, it is necessary to estimate the material balance according to the farm-environment. Vertical particulate fluxes and release fluxes were estimated at 2 stations, an ascidian farm (AF) and a non-cultivated area (control) in Jindong Bay. An in-situ benthic chamber(BelcI) was used in summer and winter season. The sedimentation fluxes of organic carbon were 72 mmol C $m^{-2}\;d^{-1}$, 93 mmol C $m^{-2}\;d^{-1}$, 34 mmol C $m^{-2}\;d^{-1}$ in Jul. AF, Feb. AF, Feb. control. The organic carbon oxidation rates were 13 mmol C $m^{-2}\;d^{-1}$, 81 mmol C $m^{-2}\;d^{-1}$, 31 mmol C $m^{-2}\;d^{-1}$, in each. The release fluxes of nutrients followed the general pattern, well. Consequently, the ratio of the organic carbon burial fluxes were 20:4:1, in each. By the estimation of the carbon circulation, it could be a scientific basis to analyze the reason of production decline for cultivated organism.

• Korean Journal of Ecology and Environment
• /
• v.38 no.1 s.110
• /
• pp.30-44
• /
• 2005

To investigate the flora and vegetation structure of vascular plants in the littoral zone of Paldang Reservoir, from April, 2003 to April 2004, nine sampling sites were selected. Along the Paldang Reservoir, 128 taxa, consisted of 51 families and 96 genera, were identified, among them, hydrophytes were confirmed as 38 taxa, which was comprised 29.7% to total taxa, whereas hygrophytes were 44 taxa and terrestrial plants were 46 taxa. Emergent hydrophytes consists of 21 taxa, including Phragmites australis and Typha angustifolia, and next, submerged hydrophytes were 8 taxa. However, the kinds and vegetation area of submerged hydorphytes were reduced compared to previous studies. In the littoral zone of Paldang Reservoir, the aquatic vegetation was widely developed near Dumulmori, Yangsuri, and Kwangdong Bridge, downstream of Kyungancheon. The average number of hydrophyte per sampling sites were 2.7 taxa, whereas hygrophytes were 2.5, and land plants were 1.8. In addition, the hydrophytes in the littoral zone of Paldang Reservoir showed the typical vertical zonation pattern like a natural swamp. These results mean that the littoral zone of Paldang Reservoir has the typical characteristics of aquatic plant ecosystem.