• The Korean Journal of Ecology
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• v.19 no.4
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• pp.321-328
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• 1996

The profile and concentration of monoterpene metabolites in the leaf and stem of Artemisia princeps var. orientalis were quantified, and seasonal variation in monoterpenes of Artemisia plant was investigated. Samples were taken from five sites at the campus of Kyungnam University during maturing season. Monoterpenes in leaf and stem were analyzed using gas chromatography-mass spectrometry (GC-MS). The major constituents of A. princeps var. orientalis in both the leaf and stem were 21 monoterpenes.$ {\alpha}-pinene,\;{\beta}-pinene,\;{\beta}-myrcene$, dl-limonene, naphthalene and unknown monoterpenes with 5.49 and 16.27 of retenstion time were present in high concentrations of compounds identified on the leaf and stem of A. princeps var. orientalis. The cmounts of total monoterpenes of leaf were from two to five times higher than stem and rapidly decreased with the time, while that of stem was constnat except early spring. Most of the high percentage of monoterpenes in the leaf were those with later retention time. These results indicated that monoterpenes yields are considered to be more variable than monoterpene composition in responding to the time in both the leaf and stem.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.79-87
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• 2012

Currently, The method to produce a brewing body for dentistry supplementation water produces a brewing body by fabrication, burying and it is heat wish in city gas and oxygen. It uses an original judgment found airplane the brewing body uses a spring of the back wait that melting temperature dissolved various alloys in by a blow pipe, and to generate centrifugal force and produces it. In addition, because it uses preheating to dissolve an alloy in general, it is hard to regulate the appropriate melting temperature of the alloy and brewing time and generates a brewing defect hereby same as gas industry and pinhole and shows the defect of the supplementation thing due to the super-heating. In this paper, We developed the high induction heating system which it could set brewing time,temperature and had durability and security,by the kind of the alloy to produce a high quality prosthetic thing brewing body.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.91-97
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• 2012

The structural analyses and experimental results for the bellows of a gas-generator liquid oxygen shut-off valve were presented. The bellows experiences axial compression and external high pressure loadings at cryogenic temperatures. The analyses were performed using EJMA (Expansion Joint Manufacturing Association) standard and the commercial FE (finite element) analysis program, Abaqus v6.9, at room and cryogenic temperatures. The spring modulus, the induced stress and the expected fatigue life of the bellows were compared respectively. The effects by the contact and the material plasticity on the FE analysis results were also analyzed. Also, FE analyses related to a burst test were presented.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.1
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• pp.99-106
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• 2006

Aircraft measurements have been executed for the purpose of monitoring the long range transported air pollution and estimation of air pollutant in/out-flux over the Yellow sea. Total 74 missions of measurements have been done since 1997, mainly in spring and fall. The main study domain was over $124^{\circ}$E $/sim$ $124^{\circ}$E, $35^{\circ}$N $/sim$ $37^{\circ}$N below 3,000m. In long-term trends, mixing ratios of $SO_{2}$N were around 2 ppbv expect in summer ( < 1 ppbv). NOx exhibited 24 ppbv and have no clear annual trends over the Yellow Sea. The concentrations of 03 were 51, 58, 41 ppbv in spring, summer and fall-winter, respectively. Backward trajectory was performed for three days to investigate the source regions of the air mass. Six regions were divided around Korea peninsular centering at $36^{\circ}$N, $126^{\circ}$E. I, II, III, IV and V regions represents in sequence northeast China and Siberia, Sandong peninsula and Balhae gulf, Sanghi and southern China, the south Pacific included Jeju island and the East sea included Japan. L region correspond to the airmass from Korea peninsula. Influx of $SO_{2}$N was approximately five times higher than outflux in yearly flux variation and showed a decreasing long-term trend since 1998. NOx outflux was average 0.095 ton/km/hr and three times higher than $SO_{2}$ outflux. In/out flux of 03 showed even distribution in yearly basis except 2002 (influx 5.45 ton/km/hr). The transported amounts from I, II, III regions were much higher than those from other region. In seasonal flux variation, influx levels of gas phases were the lowest in summer and the levels gradually increased from fall toward spring. As a result, transport of pollutants begins from fall and prevails in winter and spring.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.574-589
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• 2006

Although concentrations of hazardous air pollutants(HAPs) are very low in the atmosphere, a growing attention has been paid on such compounds due to their high toxicity and bioaccumulation potentials into human body. In order to control and manage the amount of these materials in ambient air, it is necessary to construct monitoring system of them and to know the current concentration level of HAPs above all. In this work, a wide range of HAPs has been measured in metropolitan area to recognize the present state of HAPs in this area. The measured concentration of VOCs was higher in order of Jeonnongdong, Jeongdong, and Yangsuri. The regional difference of VOCs concentration was also highest in spring. Its total VOCs was ranged from $15.17{\sim}41.45$ ppb. Benzene $0.43{\sim}2.32$ ppb showed similar concentration level with the result of previous researches in Seoul. This value is a little higher than the average concentration 0.92 ppb for national ambient air quality standards in Japan. The concentration of aldehydes in this study was lower than those of other researches. Previous works in Seoul metropolitan area showed that the concentration of formaldehyde and acetaldehyde were higher than 5 ppb. The concentration of gaseous and particulate PAHs was high in order of winter, spring, and summer More than 90% of PAHs with low molecular weight such as 2-rings and 3-rings PAHs existed in gas phase. On the other hands, PAHs with high molecular weight more than 5-rings PAHs almost existed in particulate. In spring, the concentration of gaseous PAHs was 24.38 $ng/m^3$ in Jeongdong. Among the particulate PAHs, the concentrations of Naphthalene, Benzo(b)fluoranthene, and Benzo(g, h, i)perylene were higher than others. Especially, the concentration of Benzo(a)pyrene, a important carcinogenic pollutant, was highest in winter 0.5 $ng/m^3$ and ranged from 0.03 to 0.3 $ng/m^3$ in spring and summer, which is lower than the monitoring result in 90's. These components were mainly originated from the vehicle exhaust or heating equipment use.

• Journal of the Korean Society of Systems Engineering
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• v.13 no.1
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• pp.33-39
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• 2017

This paper describes the system engineering approach for the heat transfer analysis of plus7 fuel rod for APR1400 using, a commercial software, ANSYS. The fuel rod is composed of fuel pellets, fill gas, end caps, plenum spring and cladding. The heat is transferred from the pellet outward by conduction through the pellet, fill gas and cladding and further by convection from the cladding surface to the coolant in the flow channel. The goal of this paper is to demonstrate the temperature and heat flux change from the fuel centerline to the cladding surface when having maximum fuel centerline temperature at 100% power. This phenomenon is modelled using the ANSYS FEM code and analyzed for steady state temperature distribution across the fuel pellet and clad and the results were compared to the standard values given in APR1400 SSAR. Specifically the applicability of commercial software in the evaluation of nuclear fuel temperature distribution has been accounted. It is note that special codes have been used for fuel rod mechanical analysis which calculates interrelated effects of temperature, pressure, cladding elastic and plastic behavior, fission gas release, and fuel densification and swelling under the time-varying irradiation conditions. To satisfactorily meet this objective we apply system engineering methodologies to formulate the process and allow for verification and validation of the results acquired. The close proximity of the results obtained validated the accuracy of the FEM analysis of the 2D axisymmetric model and 3D model. This result demonstrated the validity of commercial software instead of proprietary in-house code that is more costly to develop and maintain.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.1
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• pp.81-86
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• 1996

Subsea pipelines have an important role in the overall tasks of offshore oil and gas production but arc exposed to various hazards with high potential risks of damage resulting in serious economic loss and impact on ocean environment. In this paper, the dynamic free span is analysed, which is one of main risk factors against the safety of subsea pipelines and the allowable length of dynamic free span which is important for the design of subsea pipelines is determined. The allowable free span length is examined by considering the relationship between vortex shedding frequency and natural frequency of pipeline free span, and the variation of the allowable length is analysed for different boundary conditions of pipe ends. The free span is regarded as a beam on elastic foundations and the boundary condition of the beam is generalized by modelling as restrained by linear and rotational spring at each end. A non-dimensionalized curve is obtained to facilitate the determination of exact allowable length of dynamic free span for subsea pipelines and is applied to the pipelines which is to be installed in the gas fields of the south of East Sea of Korea.

• Architectural research
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• v.21 no.1
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• pp.21-29
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• 2019

Recent years in Korea, some new developed buildings are only using electricity as power for heating, cooling, bathing and even cooking which means except electricity, there is no natural gas or other kinds of energy used in such kind of building. In vehicle industry area, scientists already invented electric vehicle as an environment friendly vehicle; after that, in architecture design and construction field, buildings only using electricity appeared; the curiosity of the environment impact of energy consumption by such kind of building lead me to do this research. In general, electricity is known as a clean energy resource reasoned by it is noncombustible energy resource; however, although there is no environmental pollution by using electricity, electricity generation procedure in power plant may cause huge amount of environment pollution; especially, electricity generation from combusting coal in power plant could emit enormous air pollutants to the air. In this research, the yearly amount of air pollution by energy using under traditional way in research target building that is using natural gas for heating, bathing and cooking and electricity for lighting, equipment and cooling is compared with yearly amount of air pollution by only using electricity as power in the building; result shows that building that only uses electricity emits much more air pollutants than uses electricity and natural gas together in the building. According to the amount of air pollutants comparison result between two different energy application types in the building, residential SOFC (Solid oxide fuel cell) is simulated to apply in this building for decreasing environment pollution of the building; furthermore, high load factor could lead high efficiency of SOFC, in the scenario of simulating applying SOFC in the building, SOFC is shared by two or three households in spring and autumn to increase efficiency of the SOFC. In sum, this research is trying to demonstrate electricity is a conditioned environment friendly energy resource; in the meanwhile, SOFC is simulated efficiently applying in the building only using electricity as power to decrease the large amount of air pollutants by energy using in the building. Energy consumption of the building is analyzed by calibrated commercial software Design Builder; the calibrated mathematical model of SOFC is referred from other researcher's study.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.17 no.1
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• pp.29-38
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• 1991

As the suitable place of the forest bathing, Two places of the needle-leaf trees, which are located in the Oh-Saek mineral spring near place from the Sorak mountain, were selected. And then, Headspace gas trapping apparatus were setted in that two places and the aromatic components of the forest were adsorbed by Tenax-TA column for 24 hours. And Tenax-TA column were analyzed by the GC SE GC-MS. The analyzed components were found to contain up to between 70-80% of pollutants, which are Toluene, Methyl Chloride, Hexane, p-Xylene, Benzene, ... etc. On the other hand, the aromatic components of the forest, which give aromatheraphitical effectness, are as follow: alpha-Pinene, Limonene, 1, 8-Cin-eol, Benzaldehyde, . . . etc.

• Tribology and Lubricants
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• v.20 no.5
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• pp.245-251
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• 2004

This paper presents the effects of the bump foil stiffness on the static and dynamic performance of the foil journal bearings. Reynolds equation is used for the static and dynamic performance analyses. To consider the deflection of top foil the top foil is modeled as a elastic beam and the bump foil is modeled as a spring. So in the static performance analysis the load capacity is compared to the various bump foil stiffness and in the dynamic performance analysis the trajectory of journal center is compared to the various bump foil stiffness.