• Advances in aircraft and spacecraft science
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• v.8 no.1
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• pp.53-67
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• 2021

The increasing interest in the exploration of Mars stimulated the authors to study aerodynamic problems linked to space vehicles. The aim of this paper is to evaluate the aerodynamic effects of a flapped wing in collaborating with parachutes and retro-rockets to reduce velocity and with thrusters to control the spacecraft attitude. 3-D computations on a preliminary configuration of a blunt-cylinder, provided with flapped fins, quantified the beneficial influence of the fins. The present paper is focused on Aerodynamics of a wing section (NACA-0010) provided with a trailing edge flap. The influence of the flap deflection was evaluated by the increments of aerodynamic force and leading edge pitching moment coefficients with respect to the coefficients in clean configuration. The study was carried out by means of two Direct Simulation Monte Carlo (DSMC) codes (DS2V/3V solving 2-D/3-D flow fields, respectively). A DSMC code is indispensable to simulate complex flow fields on a wing generated by Shock Wave-Shock Wave Interaction (SWSWI) due to the flap deflection. The flap angle has to be a compromise between the aerodynamic effectiveness and the increases of aerodynamic load and heat flux on the wing section lower surface.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.91.1-91
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• 2002

1. Introduction Present study presents the basic concept of a Solid Freeform Fabrication System using a rapid prototyping procedure and optimal control for a transferring and accumulating system. And it developed a novel rapid prototyping process that can use ceramic or metal as well as polymer as a basic material. 2. Solid Freeform Fabrication System 2.1 Basic Theory A 3D CAD data of the model is converted to the 2D cross-section data of the slides. A ceramic or metal tape of thickness 0.5-1.5mm is cut by a laser beam with the cross-section data of the slide. A 3D model was obtained by transferring and accumulating the slides. The final product is manufactured by sin...

• The KSFM Journal of Fluid Machinery
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• v.19 no.3
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• pp.10-13
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• 2016

The wet-air oxidation in gravity pressure reactor is effective for organic waste treatment with energy saving under high pressure and high temperature. But its oxidation control is difficulty because its multi-phase flow characteristics is very complicated. The flow characteristics of an oxidizer feed section in the gravity pressure reactor were investigated using numerical method which are verified by comparison with experimental results. In this study, the results showed that the flow rate of oxidizer have an effect on the generation of bubble around feed section.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.5
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• pp.1356-1362
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• 2005

The purpose of this study os to investigative the effect of Carrageenan-Induced Pain on lower limb muscle and ligament of rat. To evaluate pain mechanism in muscle and ligament, pain was induced by the injection of 2% $0.1m{\ell}$ carrageenan into the left lower limb muscle of rats after rats were anesthesized with 3% enflurane. Rats were killed on 72 hours after pain induction under the anesthesia. anterior rectus femoris muscle and its ligament were removed from rat hind limb. Morphological changes of them were peformed by the observation of light and electron microscopes. In the light microscopic findings, the muscle cells were polyheadral and situated with each other without small gap in control group. nucleus of cell was seen along the cell margin, and muscle cell groups were divided by regular narrow gap in cross section. In the pain-induced group, muscle cell groups were divided each other by the irregular gap, and some of groups formed larger than other cell groups by the fusion. Intercellular gap of most cell groups were increased compared with control groups. And also, perimysium of muscle cell groups was swollen in cross section. In control group, muscle cells contacted each other closely and each cell was divided by perimysium. The intracellular gaps were not seen between myofibrills, and also striations were well defined between muscle cells in longitudinal section. In pain-induced group, muscle cells were divided by the small intracellular gaps. And also, muscle cell showed many a short cross or longitudinal intercellular gaps in longitudinal section. In light microscopic findings of control group, tendon was composed with many tendon fibers contacted each other closely without gap. The free margin of tendon was fused, and apso the tendon fibers did not invaded between muscles. In pain-induced group, tendon was divided small groups by intertendinous gap, and also the margin of tendon divided by small groups. In the free margin, tendon invaded into muscle cells, and also fibroblasts between tendon fibers were long and lance-shaped. From these results, it is suggested that pain induction by carrageenan injured rat skeletal muscle and ligament by the morphological changes.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.792-800
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• 1997

The purpose of this study was to evaluate the adaptation of self-cured glass ionomer cement and resin-modified glass ionomer cement and polyacid-modified resin composite, which are light-cured giass ionomer cements, to dentin surface. Twelve extracted human maxillary and mandibular molar teeth were used in this study. The entire occlusal dentin surfaces of teeth were exposed with Diamond Wheel Saw and smoothed with sand papers (300, 600, 1200grits). They were randomly assigned into 3 groups according to glass ionomer cements used; Control group- Fuji II, Expeimental group 1 - Fuji II LC, Expeimental group 2 - Dyract. According to the manufacturer's directions, three glass ionomer cements were bonded to exposed dentin surfaces of the tooth crown and cured. Crowns and glass ionomers were trimmed after 24hrs and sectioned horizontally and vertically with diamond saw. The interface of glass ionomer cements and dentin was examined under SEM. The results were as follows : 1. Good adatation between glass ionomer cement and dentin on the horizontal section was showed in control and experimental group 1, but the gap of $20{\mu}m$, which was observed distinct separation between glass ionomer cement and dentin, was showed in experimental group 2. 2. Good adatation between glass ionomer cements and dentin on the vertical section was showed in control and experimental group 1, but the gap of 80-$100{\mu}m$ was showed in experimental group 2. 3. Cohesive fracture within glass ionomer cements in control and experimental group 1 was showed, but no cohesive fracture was showed in experimental group 2.

• The Korean Journal of Pain
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• v.9 no.1
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• pp.178-182
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• 1996

Background: To evaluate the effect of prophylactic transdermal scopolamine in reducing nausea associated with postoperative epidural morphine. Methods: 30 healthy patients scheduled for cesarean section were given local anesthetics epidurally for surgical anesthesia. After delivery of the baby, transdermal scopolamine patch($Kimite^{(R)}$ Myung Moon Pharm. Co., Seoul, Korea) was applied to the study group(n=15) and placebo patch to the control group(n=15). Postoperative analgesia was provided soley with epidural morphine. Nausea was treated with metoclopramide. Results: During 24 hours postoperatively, the mean nausea score was significantly lower in the study group than in the control group. But the nausea incidence was not significantly different between the two groups. The mean number of times antiemetic drugs which were administered to patients were lower in the study group than in the control group($1.5{\pm}0.5$ vs $3.3{\pm}1.3$, p<0.05). Conclusion: Transdermal scopolamine patch provides antiemetic effect simply, continuously and safely, preventing nausea which could occur during administration of epidural morphine after cesarean section.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.3
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• pp.161-166
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• 2013

Purpose: This study was intended to perform a cephalometric comparison between the patients with and without obstructive sleep apnea (OSA). The factors influencing the OSA in the lateral cephalogram were also investigated. Methods: Fifty patients who had visited the Sleep Disorder Clinic at the Ajou University Hospital and evaluated with the polysomnograph (PSG) and cephalogram, were included in the study. The patients had the apnea-hypopnea episode over 5 times per hour (apnea-hypopnea index $[AHI]{\geq}5$) were diagnosed as OSA after the overnight PSG. To evaluate the hard and soft tissue profiles, the cephalometric radiograms were taken at the maximal intercuspation. The correlation between the patient's age, height, weight, body mass index (BMI) and AHI was inspected in the OSA and control group. The difference between the OSA and control group was evaluated (Mann-Whitney U Test). The cephalometric influencing factors to OSA were analyzed (Pearson's correlation coefficient) statistically using SPSS statistics. Results: The OSA Group had a significantly higher BMI than the control group. The mean lower facial height (ANS-Me) was longer in the OSA group; however, statistically significant difference was not detected in the anteroposterior craniofacial measurements. The distance between mandibular plane and hyoid bone of the OSA group was significantly longer than that of the control group. The hyoid position (MP-Hyoid) had a positive correlation between AHI (P<0.001). However, the measurements of oropharyngeal airway were not different between the two groups. The hypothesis, that the antero-posteriorly narrow oropharyngeal airway may aggravate the airway resistance and give rise to a higher AHI, was rejected in the study. Conclusion: We suggest that the lateral cephalogram may be utilized as a useful method to evaluate OSA. The patients with a lower hyoid position can be expected to have higher risks of OSA. However, a comprehensive intraoral inspection, including the soft palate and tonsilar hypertrophy, is emphasized, as the lateral cepahlogram cannot visualize the oropharyngeal status completely.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1193-1196
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• 2014

Senescence marker protein 30 (SMP30), a hepatocellular carcinoma (HCe) associated antigen had been identified by our research group. To study its mechanisms of regulation and associations with the occurrence and development of HCe, we inhibited expression by RNAi technique, and observed effects on the biological characteristics of Hep G2 cells. In cell viability assays, cell growth in the experimental group (with siRNA transfection) was elevated. In Transwell invasion assays, compared with blank and control groups, numbers of invading cells in the experimental group were significantly increased, whereas in apoptosis assays, the percentage apoptosis demonstrated no differences, but after UV irradiation, that in the experimental group was higher than the other two groups. In a word, SMP30 can inhibit the proliferation and invasion of human hepatoma cells and thus can be regarded as a cancer suppressive factor.

• Corrosion Science and Technology
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• v.8 no.6
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• pp.217-222
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• 2009

The production of advanced high strength steels requires the improvement of cooling technology. The use of high cooling rates allows relatively low levels of expensive alloying additions to ensure sufficient hardenability. In classical annealing and hot-dip galvanizing lines a mixing station is used to provide atmosphere gas containing 3-5% hydrogen and 97-95% nitrogen in the various sections of the furnace, including the rapid cooling section. Heat exchange enhancement in this cooling section can be insured by the increased hydrogen concentration. Drever International developed a patented improvement of cooling technology based on the following features: pure hydrogen gas is injected only in the rapid cooling section whereas the different sections of the furnace are supplied with pure nitrogen gas; the control of flows through atmosphere gas management allows to get high hydrogen concentration in cooling section and low hydrogen content in the other furnace zones. This cooling technology development insures higher cooling rates without additional expensive hydrogen gas consumption and without the use of complex sealing equipments between zones. In addition reduction in electrical energy consumption is obtained. This atmosphere control development can be combined with geometrical design improvements in order to get optimised cooling technology providing high cooling rates as well as reduced strip vibration amplitudes. Extensive validation of theoretical research has been conducted on industrial lines. New lines as well as existing lines, with limited modifications, can be equipped with this new development. Up to now this technology has successfully been implemented on 6 existing and 7 new lines in Europe and Asia.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.550-555
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• 2013

A hydrogel electrolyte consisting of potassium poly(acrylate) (PAAK) (3 wt%) in 6 M KOH aqueous solution is coated on poly(acrylonitrile) nonwoven separator to examine high-rate characteristics of activated carbon supercapacitor adopting the separator. The hydrogel is homogeneously coated on the surface pores of the nonwoven separator. The electrolyte uptake of the PAAK hydrogel maintains for 24 days higher than 230% and the coated separator shows slightly lower ionic conductivity ($2.9{\times}10^{-2}Scm^{-1}$) than that ($3.6{\times}10^{-2}Scm^{-1}$) of using 6 M KOH only. The activated carbon supercapacitor adopting the coated separator shows a specific capacitance higher than $27Fg^{-1}$ at $1000mVs^{-1}$ and a retention ratio higher than 97% after the 1000th cycle. This is due to strong interfacial contact of coated hydrogel electrolyte between the activated carbon electrode and the nonwoven separator.