• The Korean Journal of Quaternary Research
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• v.20 no.1 s.26
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• pp.1-8
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• 2006

Many boring investigations were achieved in Youngjong-North tidal flat to construct the Incheon International Airport Expressway. Vertical sedimentary profile of this tidal flat has been studied by analyzing these boring data. The deposits of Youngjong-North tidal flat are about 30 meters thick, and the sedimentary layers consist of basal gravel, lower mud, middle silt, middle mud, and upper silt layers in ascending order. Semi-consolidated and oxidized belt with yellowish brown color, which appears above or within middle mud layer, exists in $-3{\sim}-5$ meters altitude. There are some stratigraphical problems to admit the top surface of this oxidized belt as the unconformity surface between Holocene and Pre-Holocene tidal flat deposit.

• The Korean Journal of Quaternary Research
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• v.17 no.1
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• pp.1-6
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• 2003

One hundred fifty six pieces of woods were excavated at the muddy sand layer (post-glacial age: about 8,800 bp) above the upper peat layer from Sarori, Chungwongun, Korea in the central Korea. Due to the deteriorated structure of peat woods, all samples were embedded in PEG(polyethylene glycol) 2000 and then sectioned using a rotary microtome. Only two species were found; Alnus spp.(95%) and Ulmus spp.(5%). No conifers were found. Species composition indicates that the climate condition of central Korean peninsula around 8,800 bp was little wetter condition. The sampled region at the Sarori appeared to be a swamp or riverside.

• The Korean Journal of Quaternary Research
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• v.23 no.1
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• pp.38-41
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• 2009

Results from the most recent decade of Mars' missions to Mars highlight a liquid water and water-ice sculpted landscape. Evidence includes layered sedimentary sequences with weathered outcrops, debris flows, fluvial valleys, alluvial fans, deltas, glacial and periglacial landscapes, and geochemical/mineralogical signatures of aqueous activity, including the formation of sulfates and clays, and the leaching and deposition of elements such as potassium, thorium,and iron. Such evidence indicates weathered zones and possible paleosols in stratigraphic sequences, transport of water and rock materials to sedimentary basins, and the possible formation of extensive transient lakes and possibly transient oceans on Mars. This new evidence is consistent with Viking-era geologic investigations that reported magmatic-driven flooding, ponding to form large water bodies in the northern plains, and transient (tens of thousand of years) hydrological cycles. It may even indicate aqueous activity at present. Both endogenic (magmatic driven) and exogenic (both impact cratering and changes in orbital parameters) have influenced paleohydrologic and environmental change on Mars. Abundance of water and dynamic activity would be decisively important for the possibility of past and present life on Mars.

• Journal of The Geomorphological Association of Korea
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• v.25 no.3
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• pp.57-70
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• 2018

This study restores onshore paleo-shoreline records and establishes the nature and strain rate of neotectonism by investigating the existence and formative age of paleo-coastal sediments emerged around Sacheon-si in the Southern part of the Korean peninsula. As a result, paleo-sand bars representing 5m of the paleo-shoreline from high tide level are formed in Sacheon-si, and the formation age of these is confirmed as MIS 5c at approximately 100,000 year BP through rock surface luminescence dating to rounded gravels in paleo-sand bars. Although it is difficult to establish the uplift rate of crust precisely due to incomplete restoration of sea level records during the last interglacial stage, the uplift rate along the Southern coast of the peninsula was assumed approximately 0.72 lower than the Eastern coast during the late Quaternary in comparison to the 1st marine terrace along the Eastern coast.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.411-418
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• 2022

The purpose of this study is to investigate the relationship between sleep time and pulse pressure in Korean adults, and the research method used data from the 7th period (2016-2018) of the National Health and Nutrition Examination Survey. Subjects were 5,707 persons aged 20 years or older, and for frequency and percentage continuous data, mean and standard deviation, cross analysis and independent t-test, and stepwise logistic regression analysis for high pulse pressure were performed. SPSS WIN 18.0 version statistical program was used. was used. As a result of the study, the prevalence of hypertension was higher in the overall population (OR=1.344, 95% CI=1.002-1.803) and in women (OR=1.624, 95% CI=1.112-2.371) when sleeping for more than 9 hours compared to less than 6 hours. high, but not significant in males (OR=1.012, 95% CI=0.631-1.550). Therefore, considering the effects of inappropriate sleep time on health, public health education and management are necessary. Further research on the relationship between sleep time and pulse pressure will be needed.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.10a
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• pp.7-11
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• 1997

직경 3.5 cm, 길이 1.5 m 의 석영관 내에서 염화제1철 증기를 수소로 환원하여 철 초미립자를 제조하였다. 염화제1철의 증발조건, 염화제1철 증기와 수소의 혼합방법, 반응물의 예비가열온도, 반응온도, 염하제1철의 농도, 반응기내 체류시간이 생성된 철 입자의 크기 및 크기분포에 미치는 영향을 조사하였다. 철 입자의 평균직경은 40-88 cm 이고, 기하표준편차는 1.4 정도로 나타났다. 철 입자들은 자기적 성질에 의해 서로 연결되어 체인을 형성하였으며, 전자회절분석 결과 단결정이었다. 평균입경 55nm 철 입자들의 항자력은 900 Oe, 포화자화값은 130 emu/g 이었다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1986.06a
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• pp.10-20
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• 1986

I. 윤활기유 제조시설소개 개요 1) 고급 윤활기유(HVI)생산공장으로서 그간 수입에만 의존하던 최고급 품질의 기유를 국내 수요업체에 안정공급 2) 세계 최신 공정인 Gulf Lube Oil Hydrotreating Process Type III (수소첨가 개질공정)채택 3) 국내 최초일뿐 아니라, 세계에서도 일본, 카낟에 이어 3번째로 건설 1. 고품질 제품 생산-고점도 지수, 산화안정성 및 열안정성 우수, 잔류탄소분, 윤황분, 질소분 극소, 방향족 성분 및 회분 극소, 색상 양호 2. 첨가제(특히 산화방지제 및 점도 지수 향상제)사용효과 상승으로 완제품 생산시 생산비 감소 3. 동일 VI 제품 생산기준 수율이 높음 - Hydrocarbon Structure 변화로 원료 유중 부적합성분의 윤활기유화 4. Severity 조절로 Production Mode 변경 용이 5. 양질의 부산물 생산 - HDT Naphtha, Middle distillate 6. 용제 추출기유는 원유종류 및 성상에 따라 제품특성이 결정되나, 사용가능 원유가 다양 하면서도 제품특성 및 품질이 일정함.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.189-192
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• 2003

This paper summarizes a satellite program-specific performance requirements and test results for the verification of standard mono-propellant hydrazine thruster (MRE-1) producing 0.95 lbf (4.2 Newtons) nominal steady-state thrust at an inlet pressure of 350 psia (2.41 Mpa). Performance characteristics are shown in terms of thrust behavior at steady state and pulse mode firing. Hot firing test philosophy is briefly introduced, too.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.4
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• pp.39-47
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• 2000

This paper presents the sinusoidal tracking controller in error to eliminate the steady state control error and to improve the transient characteristics for input current in voltage source PWM converter with input current estimation. The estimation method of input current values and configuration of controller are described. DC output voltage is controlled by PI controller, and sinusoidal tracking current controller which tracks directly AC input current is used as input current controller. The sinusoidal tracking current controller can be used without any coordinate transformation algorithms.It is proved that the steady state deviation of input current reduces to zero and the proposed control system is not affected by input voltage from transfer functions of input current control system. The validity of proposed scheme is verified by simulations and experimental results for load resister and input voltage variation.

• The Journal of the Petrological Society of Korea
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• v.20 no.1
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• pp.39-59
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• 2011

To get the geologic information data such as rock resources, industrial ground, development planning and so on, distribution ratios of constituent rocks with geologic age and rock type were obtained in Gyeongnam, Ulsan and Busan areas by ArcGIS 9.3 program, digital geologic and geomorphic maps of 1 : 250,000 scale. Geologic ages and rock types in the Gyeongnam area can be divided into 6 and 40, respectively. Their distribution ratios of the geologic ages are decreasing in the order of Cretaceous, Precambrian, Quaternary, Jurassic, Triassic and Tertiary. They show the wide ranges of 1.35-57.36%, and the former makes the most dominant ratio. Major rock types are 24 ones, all of which occupy the ratio of 94.58% and relatively narrow ranges of 1.15-13.64% in the area. Among them, andesite and andesitic tuff shows the more or less dominant ratio, and separately develops in the northeast, mid east and south parts of the area. In the Ulsan area, geologic ages and rock types can be divided into 3 and II, respectively. Their distribution ratios of the geologic ages are decreasing in the order of Cretaceous, Quaternary and Triassic. They show the very wide range of 6.90-79.21%, and the former makes the most prevailing ratio. Major rock types are 9 ones, which totally occupy the ratio of 98.63% and more or less wide ranges of 1.50-39.01% in the area. Among them, Jindong formation shows the most dominant ratio, and widely develops in the inner and eastern part of the area. In the Busan area, geologic ages and rock types can be divided into 3 and 10, respectively. Their distribution ratios of the geologic ages are decreasing in the order of Cretaceous, Quaternary and Tertiary. They show the wide ranges of 6.73-47.02%, and the two former makes the most dominant ratio of 88.03%. Major rock types are 6 ones, all of which occupy the ratio of 93.02% and relatively wide ranges of 4.07-47.02% in the area. Among them, alluvium forms the most dominant ratio, which mostly develops in the lower Nagdong River, West Nagdong River and Suyeong River.