• Journal of Powder Materials
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• v.8 no.1
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• pp.13-19
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• 2001

Ni and NiO particles were made by a combustion synthesis process. The characteristics of synthesized powders were investigated with various kinds and amounts of fuels such as urea, citric acid and glycine. Ni phase particles without NiO phase were obtained through combustion synthesis process in air atmosphere with-out further calcinations process, when the content of glycine was 2.44 times of the stoichiometric ratio in the precursor solution. Primary particle sizes of synthesized Ni and NiO particles were about 20∼30 nm.

• Journal of Chest Surgery
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• v.27 no.2
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• pp.128-131
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• 1994

Recently we performed video-assisted thoracoscopic[VAT] examination and bullectomy under local anesthesia. Of the 10 patients undergoing VAT examination under local anesthesia with primary spontaneous pneumothorax, 8 patients underwent VAT bullectomy under local anesthesia using endo-GIA; 7 patients discharged within 24 hours after operation; 1 patient had an air leak after operation, so chemical pleurodesis with doxycycline was performed and discharged postoperative day 3. There have been no recurrence to date[60-120 days after operation]. We think spontaneous pneumothorax can be treated on an out-patient basis.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.545-553
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• 2003

To achieve good dentin bonding, we must obtain proper wet dentin surface. The purpose of this study was to compare dentin surface according to different wetness degree by AFM image as studying how to obtaining proper wet dentin surface. Intact recently extracted primary teeth were used in the study. The extracted teeth were stored in distilled water at $4^{\circ}C$ until prepared. The teeth were used to prepare 1mm thick dentin disks with exposed surfaces parallel to the occlusal surfaces. The surface of the dentin were polished with polishing disk. The sample were ultrasonically cleaned with distilled water. The sample of each group were treated by different ways. We compared dentin surface of each group by AFM image. From the experiment, the following results were obtained. 1. Acid etching in the dentin surface of primary teeth, resulted in the removal of the smear layer, which opened dentinal tubules, caused the demineralization of peritubular and intertubular dentin, and exposed a collagen-rich transition zone. 2. If the etched dentin was so dehydrated, the intertubular dentin surfaces deceased in height and the diameters of the dentinal tubules decreased slightly. 3. In the group dried with compressed air for 20 seconds at 2 cm, the dentin surfaces were too excessive dried and dehydrated. 4. In the group dried with compressed air for 3 seconds at 2 cm, dry cotton, wet cotton, microbrush and absorbent tissue paper, the dentin surfaces were properly wet.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.72-79
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• 2008

In this study, changes in the physicochemical properties and functional components of uncooked foods, including carrots, cabbage, shiitake (Lentinus edodes) and white button (Agaricus bisporus) mushrooms, sea mustard, and laver treated with electrolyzed water were investigated. No changes were observed in the primary compositions of any of the materials that were hot air- or freeze-dried after being treated with electrolyzed water. The lightness (L), redness (a), and yellowness (b) values of the carrots, shiitake, and laver were not affected by drying, while changes did occur in the cabbage (L-, a-, and b-values), mushrooms (a-value), and sea mustard (b-value) specimens that were hot air- or freeze-dried following the treatments with electrolyzed water. The dietary fiber contents of all the materials increased when they were hot air-dried. Vitamin C content decreased when the samples were treated with alkalic electrolyzed water. No changes occurred in the lectin, $\beta$-carotene, or total phenolic compound contents after the electrolyzed water treatments, suggesting that electrolyzed water could be used effectively as a pasteurization step for uncooked carrots, cabbage, shiitake and white button mushrooms, sea mustard, and laver.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.3
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• pp.89-100
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• 2017

In order for the international aviation community to efficiently and safely manage the gradual increase of air passenger demand, direction suggestions of airport traffic prediction based on future airport capacity requirements, airport design and infrastructure establishment is utilized by airport traffic data that is m comparable internationally. It is a global trend to pursue more efficient airport operating system structure to accept air passenger demand through more realistic comparable data in order to escape from the structure of reckless airport establishment and infrastructure composition based on passenger demand predictions referring to simple statistical data that has existed in the past. This study aimed to seek effective operational measures for the New Jeju airport scheduled to be opened in 2025 by time-series analysis. This study also analysed airport operation strategies, air traffic distribution strategies, cargo volume increase rates and its effectiveness of airports adopting the multi-airport system that have similar operational practices and geographical conditions. This study sought the most appropriate multi airport system application measures for New Jeju airport to promote efficiency and international competitiveness.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.2
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• pp.119-126
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• 1991

Air pollution is directly and indirectly associated with the toxicology through the increase of mortality, the decrease of oviposition rate, and the decline of insect population, as well as the disruption of equilibria with higher or lower trophic levels. To investigate intrinsic decrease rates, oviposition period, and emerging rates of pupae of house fly under air pollution stresses, healthy individuals of Musca domestica L. were collected in the field, cultured in the laboratory for 2 $\sim$ 3 generations, and artificially exposed to $O_3 (4 ppm) in automatically controlled air pollutant fumigation chambers. Results from this study are summarized as follows: 1. Survivorship curves of both control group and exposed groups of healthy house fly to 4 ppm $O_3$ have linearly or stair-like decreasing trends of revers S-shape. 2. For cohorts exposed to 4 ppm of $O_3$, intrinsic decrease rate of cohort exposed for 2 hours significantly increases compared to that of control group, slight increases were observed for those exposed for 4 hours and 8 hours, which shows no distinct relationships between exposure period and intrinsic decrease rate. 3. While the numbers of pupae of exposed cohorts increase with the increase of exposure period, emerging rate shows a distinct decrease. 4. The relationships between emerging rate (E) of pupae and the exposure period (T) for cohorts exposed to 4 ppm of $O_3$ are expressed with the equation, E (%)=21.027 - 7.942 ln (T).

• Journal of the Korean Society of Combustion
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• v.16 no.3
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• pp.12-20
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• 2011

Oxy-coal combustion for $CO_2$ capture in coal power plants entails a mode switching from air-firing to oxyfiring. In this study, procedure of the mode switching was investigated and discussed through experiments in pilot scale facilities: (1) a 0.3 $MW_{th}$ furnace with a vertical single burner and a FGR(Flue Gas Recirculation) system (2) a 1 $MW_{th}$ furnace with horizontal 4 burners and a FGR system. Principle of the mode switching was established and performed with control of FD fan, FGR fan, ID fan and oxygen flow rates. We have found that equivalence ratio in the oxy-firing mode should be increased more than that in the air-firing to achieve stable mode switching. Control of FD, ID and FGR fans should be performed carefully in the mode switching, in the sense of complete combustion and flame attachment. Moisture contents in the ash and the flue gas recycled to the primary oxidizer stream should be removed to prevent condensation, corrosion and duct clogging.

• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.122-128
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• 2000

Aerodynamic optimization of an automotive air-conditioning blower is a hard task because of the highly complex flow phenomena related to three-dimensional flow separations and the unsteady nature caused by the interaction between primary and secondary air flows throughout the fan. In this paper, an aerodynamic study on a forward-curved centrifugal fan has been carried out Firstly we obtained the fan performance curves versus flow rates showing its unstable nature in the surging operation range. Secondly aerodynamic characterizations were carried out by investigating the velocity and pressure fields in the casing flow passage using a 5-hole pilot probe, at different operating conditions. Surface flow pattern near the cut-off area exhibits similar flow behavior above the best efficiency operating point, although the pressure level increases substantially with the Increase of flow rate. Vorticity in the casing passage flow occurs in all (low rates, downstream from the r-Z plane $\theta$=120 deg., where the position of its core changes with the circumferential location. Although complex, the general flow behavior were common, giving insight in its main aerodynamic features.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.806-811
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• 2001

Since the characteristics of combustion and pollutant in Diesel engines were mainly effected by the characteristics of in-cylinder gas flow and fuel spray, an understanding of those was essential to the design of the D.I. Diesel engines. The improvement of volumetric efficiency of air charging into combustion chamber is a primary requirement to obtain better mean effective pressure of an engine. Since parameters such as the air resistances in intake and exhaust flow passages, valve lift and valve shape influence greatly to the volumetric efficiency, it is very important to investigate the flow characteristics of intake and exhaust port which develops air motion in the combustion chamber. In this study, two approach methods were used for design intake and exhaust port; experiment and computation which were made by using steady flow test rig and commercial CFD code. This paper presents the results of an experimental and analytical investigation of steady flow through the prototype cylinder head ports and valves of the HHI's H21/32 HIMSEN Engine.

• Nuclear Engineering and Technology
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• v.32 no.4
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• pp.350-360
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• 2000

In Korea, the dose limits are reduced and are set at the ICRP-60 iimits. However, derived limits tabulated as MPC in air and water are still specified in Notice No.98-12. There are some discrepancies between the primary dose limits and MPCs in air and water. Therefore, in order to accept ICRP-60 recommendations fully, derived limits such as ALI, DAC, ECL for radiological protection against ionizing radiation based on ICRP-60 recommendations were calculated using modified methods of those of 10 CFR part 20, dose limits and committed effective dose coefficients of the Basic Safety Standards of the IAEA. The derived limits in this study were also compared with those prescribed in 10 CFR part 20 as well as MPCs of Notice No. 98-12 in order to analyze the impact of implementing derived limits on nuclear facilities. ECLs in air and water for the control of radioactive discharge into the environment in this study are shown to have lower values (i.e. more conservative), for most part, than those in Notice No. 98-12. Especially, for uranium elements, ECLs in water are approximately a magnitude in the order of two lower than those in Notice No.98-12.