• 해운
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• s.99
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• pp.14-20
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• 2013

석유생산이 정점을 짝은 후 감소한다는 피크오일(Peak Oil)의 대표사례로 지목되던 미국에서 원유생산이 39년 만에 증가세로 전환됐다(<그림 1> 참조). 2012년에는 WTI 유가 1% 하락에도 불구하고 미국은 주요 신유국 중에서 이라크에 이어 세계 두 번째로 빠른 석유생산 증가율(8.9%)을 기록하면서 세계 최대 석유 생산국으로 발돋움했다. 최근 들에서는 멜릴린치와 삭소은행 등 일부 투자은행들이 2년 내에 WTI 유가가 배럴당 50달러로까지 하락할 수 있다는 견해를 내 놓았다. 석유 생산 확대세가 이어지면서 미국내에서 거래되는 유가가 절반 가까이 하락할 수 있다는 것이다. 미국이 빠른 석유 생산 확대를 보이는 데에는 비전통 석유인 타이트 오일(Tight Oil)의 역할이 크다. 타이트 오일은 셰일가스가 매장된 셰일층, 즉 모래와 진흙이 굳어진 지하 퇴적암층에 존재하는 원유다. 탄소 함유량이 많고 황 함량이 적은 경질유이기 때문에 LTO(Light Tight Oil)라고 지칭되기도 한다. 일부에서는 셰일층이라는 매장위치를 감안해 셰일오일(Shale Oil)이라 부르기도 한다. IEA와 EIA 등 주요 에너지 기관들은 동식물의 사체가 원유로 변하기 전 단계인 케로젠(Kerogen)이 주성분인 오일셰일(Oil Shale)과 오일셰일에 열을 가해 합성 석유로 만든 셰일오일을 타이트 오일과 구분하고 있다. 타이트 오일의 잠재력을 평가하고 중장기 생산 전망과 이로 인한 국제석유시장 파급효과를 살펴본다. 다음은 엘지경제연구원에서 발표한 '셰일혁명으로 부상한 Tight Oil, 유가 안정 역할 커진다'의 주요 내용을 요약 정리한 것이다.

• Advances in aircraft and spacecraft science
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• v.1 no.3
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• pp.311-330
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• 2014

Environmental impact of aircraft emissions can be addressed in two ways. Air quality impact occurs during landings and takeoffs while in-flight impact during climbs and cruises influences climate change, ozone and UV-radiation. The aim of this paper is to investigate airports related local emissions and fuel consumption (FC). It gives flight path optimization model linked to a dispersion model as well as numerical methods. Operational factors are considered and the cost function integrates objectives taking into account FC and induced pollutant concentrations. We have compared pollutants emitted and their reduction during LTO cycles, optimized flight path and with analysis by Dopelheuer. Pollutants appearing from incomplete and complete combustion processes have been discussed. Because of calculation difficulties, no assessment has been made for the soot, $H_2O$ and $PM_{2.5}$. In addition, because of the low reliability of models quantifying pollutant emissions of the APU, an empirical evaluation has been done. This is based on Benson's fuel flow method. A new model, giving FC and predicting the in-flight emissions, has been developed. It fits with the Boeing FC model. We confirm that FC can be reduced by 3% for takeoffs and 27% for landings. This contributes to analyze the intelligent fuel gauge computing the in-flight fuel flow. Further research is needed to define the role of $NO_x$ which is emitted during the combustion process derived from the ambient air, not the fuel. Models are needed for analyzing the effects of fleet composition and engine combinations on emission factors and fuel flow assessment.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.638-642
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• 2010

The spinel material $Li_4Ti_5O_{12}$ has attracted considerable attention as an anode electrode material for many battery applications owing to its light weight and high energy density. However, the real capacity of $Li_4Ti_5O_{12}$ powder as determined by the solid-state method is lower than the ideal capacity. In this study, we investigated the effect of the dopants in M-doped spinel $Ba_xLi_{4-2x}Ti_5O_{12}$(x=0.005, 0.05, 0.1) powders prepared by the solid-state reaction method and used as the anode material in lithiumion batteries. The results confirmed the effect of the Ba and Sr dopants on the powder properties of the spinel $Li_4Ti_5O_{12}$, which exhibited a pure spinel structure without any secondary phase in its XRD pattern. Moreover, the electrochemical properties of the spinel M-LTO materials were investigated using a half cell. The electrochemical data show that cells with anodes made of undoped $Li_4Ti_5O_{12}$ and Ba- and Sr-doped $Li_4Ti_5O_{12}$ have discharge capacities of 97, 130, and 112 mAh/g, respectively, at the first cycle. Moreover, the Ba- and Sr-doped spinel $Li_4Ti_5O_{12}$ demonstrated good properties in the mid-voltage range at 1.55 V, showing stable cyclic voltammogram properties which surpassed those of the same material without Ba or Sr at 1 C after 100 cycles.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.85-85
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• 1999

Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT)는 높은 유전율로 인해 강유전체 메모리 소자의 응용을 위한 연구가 되고 있으며 또한 전왜(electrostrictive)성을 갖고 있어 이력현상을 갖지 않음으로 최근 들어 미세전기기계소자(MEMS)로의 연구가 활발히 되고 있다. 본 연구에서는 MEMS 소자로서의 응용을 위해 저응력 SiNx가 형성된 Si 기판위에 Pt 전극 혹은 산화물 전극 SrRuO3를 갖는 PMN-PT 박막 캐패시터를 제조하였다. 박막 하부의 구조는 금속전극의 경우 Pt/Ti/LTO/SiNx/Si이고 산화물전극은 SrRuO3/Ru/SiNx/Si의 구조를 갖는다. PMN-PT 박막은 alkoxide를 기반으로 회전 coating 방법을 사용하여 박막 하부층의 변화를 주어서 성장시켰다. PMN-PT 용액의 합성은 분말합성법에서 사용하는 columbite 방법을 응용하여 상대적으로 반응정도가 낮은 Mg를 Nb와 우선 반응하여 Mg-Nb solution을 얻고 Pb-acetate 용액과 합성하여 PMN을 제조한 후 PT를 반응시켜서 제조하였다. PMN-PT 박막에서 동일한 공정조건 하에서 박막 하부층의 구조에 따라서 PMN-PT 박막의 조성이 A2B2O6의 조성을 가지는 파이로클러어상이 형성되거나 또는 ABO3인 페로브스카이트상이 형성되는 것을 관찰하였다. 금속 전극인 Pt를 하부전극으로 사용한 경우는 혼재상이 형성되어 패로브스카이드 PMN-PT를 얻기 위해 seed layer로서 PbTiO3를 사용하였으며 이러한 seed layer 위에 형성된 PMN-PT를 형성하는 경우 rutile 구조인 RuO2 위에 성장시킨 PMN-PT는 파이로클로어와 페로브스카이트의 혼재상이 얻어졌으나 pseudo-perovskite 구조인 SrRuO3 박막 위에 형성된 PMN-PT 박막에서는 페로브스카이트가 주된 상으로 얻어졌다. 즉 하부층(전극 또는 seed layer)으로 perovskite 구조를 갖는 박막을 형성하게 되면 페로브스카이트를 갖는 PMN-PT 박막을 얻을 수 있었다. 전기적인 특성은 상부전극으로 Pt를 사용하여 HP 4194A로 측정을 하였다. PT seed layer를 포함한 PMN-PT 박막은 유전상수 1086과 유전손실 2.75%을 가졌다.

• Journal of Sensor Science and Technology
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• v.7 no.1
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• pp.73-82
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• 1998

In silicon surface micro-machining, the newly developed GPE(gas-phase etching) process was verified as a very effective method for the release of highly compliant micro-structures. The developed GPE system with anhydrous HF gas and $CH_{3}OH$ vapor was characterized and the selective etching properties of sacrificial layers to release silicon micro-structures were discussed. P-doped polysilicon and SOI(silicon on insulator) substrate were used as a structural layer and TEOS(tetraethyorthdsilicate) oxide, thermal oxide and LTO(low temperature oxide) as a sacrificial layer. Compared with conventional wet-release, we successfully fabricated micro-structures with virtually no process-induced striction and residual product.

• Economic and Environmental Geology
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• v.33 no.3
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• pp.181-193
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• 2000

This study was undertaken to evaluate the drinking water quality based on physicochemical properties and chemical compositions of the supply water in the Daedeok Campus, and to verify the analytical reliabilities of ICP-MS and IC equipped in the Central Research Facilities at Chungnam National University , Korea. The supply water belongs to $Ca^{2+}-({HCO_3}^-+{SO_4}^{2-})$type, whereas the original water from the Daecheong lake belongs to $(Ca^{2+}-(Mg^{2+})-{HCO_3}^-$ type. Generally, temperature (14.1$^{\circ}C$), pH (6.95), Eh (0 mV), electrical conductivity (117${\mu}$S/cm) and TDS (86.975mg/l) of supply water were higher than those of original lake water . Results using WATEQ4F revealed that potentially toxic ions of the supply water might exist mainly as free metals ($M^{2+}$) and a small amount as ${CO_3}^{2-}$ and $OH^-$ complexes. Also, the water composition belongs to the kaolinite field. Calculated average enrichment indies of the supply water normalized to lake water for anions, mamor cations, toxic cations and total ions are 1.05 , 1.56, 13.05 and 1.17 , respectively. Those values of the ground water in the Daedeok Campus showed 1.71, 4.78, 5.71 and 2.49 , respectively. However , contents of all constituents of these water are within the drinking water standard. All samples were filtered before the chemical analysis. Pale yellow or yellowish brown colored materials of colloidal particles coated the filter paper to thickness of 0.02 to 0.2mm. these are mainly Fe-Cy-Zn compounds with traces of Ni and Pb, the net weights of which compounds range from 0.01to 3.20mg/l. Most elements did not show any conceivable filtering effect of Cu, Fe and Zn. Especially, mean concentration of total Fe decreased considerably from 168.52${\mu}g$/lto 42.58${\mu}g$/l by filtering .

• Journal of Environmental Science International
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• v.22 no.7
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• pp.823-836
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• 2013

Emissions of air pollutants and greenhouse gases (GHGs) from aircraft activities at 11 small-scale airports were investigated using the emissions and dispersion modeling system (EDMS) version 5.1.3 during the two year period of 2009~2010. The number of landing and take-off (LTO) at these airports was dominant for the aircraft type B737, accounting for more than 60% of the total LTOs. Out of the 11 small-scale airports, Gwangju (GJ, RKJJ) airport was the largest emitter of air pollutants and GHGs, whereas Yangyang (YY, RKNY) airport was the smallest emitter. The emissions of $NO_x$ and VOCs in 2010 at the 11 airports ranged from 1.9 to 83 ton/y and 0.1 to 17 ton/y, respectively. In 2010, the emissions of $CO_2$ ranged from 394 to 21,217 ton/y. The emissions of most air pollutants (except for $NO_x$ and $PM_{10}$) and GHGs were estimated to be the highest in taxi-out mode. The highest emissions of $NO_x$ and $PM_{10}$ were emitted from climb-out and approach modes, respectively. In addition, the total LTOs at the 11 small-scale airports accounted for the range of 9.3~9.9% of those at four major international airports in Korea. The total emissions of air pollutants and GHGs at the 11 airports ranged from 4.8 to 12% of those at the four major airports.

• The Korean Journal of Archival Studies
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• no.40
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• pp.3-27
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• 2014

The purpose of the enactment of the 'Law on the National Archives of Korea' should be to secure the accountability and to shape up the improved governance system in the field of records and archival management, which will contribute to the strengthening of democracy in records management and eventually to the widening of the democratic progress in Korea. On the basis of the above recognition and by way of notion called 'horizontal accountability', this paper suggests the way to secure the National Archives of Korea's independency. And the way to reorganize the National Records Management Committee based on the pluralism and the 'multi-layered' governance system is also investigated. One of the main directions in the suggested law should be for the autonomy and transparency in the operation of the National Archives of Korea. This paper tries drawbacks and limitations of the 'Bill on the National Archives of Korea' introduced to the National Assembly last year, and suggests the alternatives as wel lto get further forward with related discussion.

• Korean Journal of Materials Research
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• v.31 no.11
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• pp.614-618
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• 2021

As the size of market for electric vehicles and energy storage systems grows, the demand for lithium-ion batteries (LIBs) is increasing. Currently, commercial LIBs are fabricated with liquid electrolytes, which have some safety issues such as low chemical stability, which can cause ignition of fire. As a substitute for liquid electrolytes, solid electrolytes are now being extensively studied. However, solid electrolytes have disadvantages of low ionic conductivity and high resistance at interface between electrode and electrolyte. In this study, Li₇La₃Zr₂O₁₂ (LLZO), one of the best ion conducting materials among oxide based solid electrolytes, is fabricated through RF-sputtering and various electrochemical properties are analyzed. Moreover, the electrochemical properties of LLZO are found to significantly improve with co-sputtered Li₂O. An all-solid thin film battery is fabricated by introducing a thin film solid electrolyte and an Li₄Ti₅O₁₂ (LTO) cathode; resulting electrochemical properties are also analyzed. The LLZO/Li₂O (60W) sample shows a very good performance in ionic conductivity of 7.3×10^-8 S/cm, with improvement in c-rate and stable cycle performance.

• Journal of Korea Trade
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• v.25 no.2
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• pp.46-57
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• 2021

Purpose - In terms of human resource management, many Korean enterprises in China have experienced problems such as frequent resignations of Chinese employees and labor disputes. This can be mainly attributed to the fact that Chinese employees are not consistent with Korean vertical management methods, which is closely related to the national culture theory proposed by Hofstede, specifically the dimension of power distance and long- versus short-term orientation (LTO). Therefore, this research aims to investigate cultural differences between Korea and China from these two dimensions, and the impact on the human resource management of Korean-invested enterprises in China. Design/methodology - This research first utilizes the latest data (Wave 7) of the World Values Survey (WVS) to verify the difference in power distance and long- versus short-term orientation between Korean and Chinese cultures using responses from Korea and China, and then uses case analysis to analyze the impact of this cultural difference on the human resource management of Korean enterprises in China. Findings - Our main findings can be summarized as follows. Korea and China have significant differences in power distance and long- versus short-term orientation. In terms of power distance, Korean respondents show higher power distance compared to Chinese respondents. In the dimension of long- versus short-term orientation, it was found that Chinese respondents showed a shorter-term orientation, whereas Korean respondents showed a longer-term orientation. Originality/value - Previous studies put focus on the power distance and individualism-collectivism dimensions to explain cultural differences between Korea and China, and generated contradictory results. This research further confirms the cultural differences between Korea and China from the dimensions of power distance and long-versus short-term orientation using secondary data. The comparative studies from this perspective have long been underexplored and lack empirical confirmation.