• Journal of the Korean GEO-environmental Society
• /
• v.13 no.11
• /
• pp.43-50
• /
• 2012

In this research, the value of consolidation index was investigated. The range of the investigated standard deviation was analyzed and the deviation based settlement was calculated. Also, the compression index, which is the effect of the uncertainty in the ground was analyzed using the flimsy ground construction method. The settlement behavior in each embankment compaction stage was analyzed by applying the precompression load method, drainage expediting method, and displacement method through numerical analysis. In addition to the above, the settlement behavior was studied by analyzing the Piled Raft method which is stable for long term settlement. As a result, the final settlement amount based on average analysis results was that the settlement based on each of the average interpretation value, mean value of the maximum and minimum value and average compression index was different. The result of the comparison shows the difference in variation coefficient by the difference in time. Amongst them, the Piled Raft method shows the most consistent variation coefficient regardless of time and it also was least affected by the compression index of uncertainty.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.20 no.1
• /
• pp.83-92
• /
• 2007

There are many numerical methods to solve large-scale fluid-structure interaction(FSI) problems. However, these methods require very fine mesh to achieve the reasonable numerical accuracy and stability due to the concentrated and volatile hydrodynamic pressure caused by the liquid sloshing. Consequently, the numerical analysis targeting for the long-period time response with the desired numerical accuracy Is very highly time-consuming. The aim of this paper is to suggest a new method to analyze the hydroelastic behavior of the LNGC containment by using the global-local numerical approach. The reliability of the presented method is firstly examined, and then its efficiency is demonstrated by presenting that the long-period local responses of the LNGC containment are obtained with relatively short CPU time.

• Proceedings of the Korea Technology Innovation Society Conference
• /
• 1999.05a
• /
• pp.409-419
• /
• 1999

전기기술은 기술의 특성상 민간에 대한 유인이 적은 공유성 기술이나 대학 또는 기업이 감당하기 어려운 대형복합기술의 비중이 높으며, 최근 들어 전력산업의 구조개편 등에 따라 국가적 기술개발수요가 확대됨과 동시에 전기기술의 이용분야 확대와 타 기술과의 융합화 및 대형화로 신기술수요가 늘어나고 있다. 현재 우리 나라의 전기기술 R&D체제에서는 공공기술에 대한 사각지대가 발생하고 있음에도 불구하고 국가차원의 R&D 공급이 미약하여, 거대한 시험설비와 첨단고가장비를 필요로 하는 시스템기술로 일부 기기나 시스템운용을 제외하고는 개별기업이나 전력회사에 대한 기술개발 유인이 크지 않으며, 따라서 전기기술분야의 R&D 실태 파악과 역할에 대한 검토를 통해 R&D 주체별 기관특성에 맞는 국가 R&D체계의 정립이 필요한 실정이다. 따라서, 앞으로는 전기기술분야의 국가 R&D 목표 및 기본전략에 따라 국가 R&D 자원의 규모, R&D 주체간의 역할분담 등 전반적인 R&D 체계의 구축이 선행되어야 하며, 이를 통해 기관별 Mission 및 고유기능을 토대로 전문성 제고와 특성화를 유도할 수 있는 연구여건의 조성이 시급하다 하겠다. 특히, 장기대형연구, 원천기술연구, 기초기반연구, 연구기반구축, 인력양성 등 필수적 국가기능에 대해서는 기관별 특성에 따라 안정적인 역할수행이 가능하도록 역할분담 및 정책적 지원을 하되, 그 밖의 영역이나, 민간 및 전력회사의 독자적인 R&D에 대해서는 경쟁 및 협력을 통한 연구효율성 향상을 유도하는 방향으로 나가는 것이 바람직할 것이다. 국가적 전력기술 R&D의 효과적인 수행과 실효성 확보를 위해서는 재원확보가 선행되어야 하며, 이를 위한 방안으로는 기존의 전력사업자에게는 기술개발충당금 또는 전기요금 중 일정비율을 국가적 R&D 재원으로 설정할 수 있을 것이며. 신규 사업자에게도 규제비용의 차원에서 일정 부담금을 부과하는 방법이 가능할 것이다. 이러한 재원을 가지고 사업성격 및 R&D 유형에 따라 역할분담에 따른 지원, 정책적 사업, 경쟁적 사업공모 등을 통해 지원분야 및 규모, 대상기관 등에 대한 선별적인 지원이 이루어져야할 것이다.

• Analytical Science and Technology
• /
• v.13 no.6
• /
• pp.693-698
• /
• 2000

The object of this series of experiments was aimed for the systematic and long-term radioactivity monitoring through indirect search of C-14 concentration level changes in the natural conditions around the operating nuclear facilities. The result of environmental radioactivity level through tree-ring analysis is increased after operating nuclear facilities and such a level can be proved to relate power generation closely. The measured result of ${\delta}^{13}C$ through the treatment of cellulose can be showed the level -30‰. This figure is very different from one which is measured the -17‰ of air sample by passive air sampling and -8‰ of air sample by active air sampling. And these differences can be assumed as isotope fractionation by photosynthesis, but the problem is more study as needed.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.425-428
• /
• 2008

To use lightweight aggregate concrete with the structural material, it was need to evaluate property of mechanic and drying shrinkage and creep of the lightweight aggregate concrete, but these weren't. So the purpose of this study which it sees follows the mechanical property of the eco lightweight aggregate concrete according to the water binder ration in the high strength concrete. Eco lightweight aggregate was made with clay and crushed rock in this study. To make experiment, water binder ratio was divided 35% and 39%. And the fresh concrete properties were that slump flow was 500${\pm}$50mm, air contents was 2.0${\pm}$1.0%. It evaluated the hold a drying shrinkage and the creep the effect, it analyzed quality and reliability of the eco lightweight aggregate concrete.

• Journal of the Korean Electrochemical Society
• /
• v.16 no.3
• /
• pp.157-161
• /
• 2013

Porous $LiMn_{0.6}Fe_{0.4}PO_4$ (LMFP) was synthesized by a sol-gel process. Uniform dispersion of the conductive carbon source throughout LMFP with uniform carbon coating was achieved by heating a stoichiometric mixture of raw materials at $600^{\circ}C$ for 10 h. The crystal structure of LMFP was investigated by Rietveld refinement. The surface structure and pore properties were investigated by SEM, TEM and BET. The LMFP so obtained has a high specific surface area with a uniform, porous, and web-like nano-sized carbon layer at the surface. The initial discharge capacity and energy density were 152 mAh/g and 570 Wh/kg, respectively, at 0.1 C current density, and showed stable cycle performance. The combined effect of high porosity and uniform carbon coating leads to fast lithium ion diffusion and enhanced electrochemical performance.

• Applied Chemistry for Engineering
• /
• v.32 no.4
• /
• pp.456-460
• /
• 2021

A potentiometric sodium-ion (Na⁺) sensor was prepared using a screen-printing process with carbon and silver inks. The two-electrode configuration of the sensor resulted in potential differences in Na⁺ solutions according to Nernstian equation. The obtained Na⁺-sensor exhibited an ideal Nernstian sensitivity, fast response time, and low limit of detection. The Nernstian response was stable when the sensor was tested for repeatability and long-term durability. The Na⁺-selective membrane coated onto the carbon electrode selectively passed sodium ions against interfering ions, indicating an excellent selectivity. The portable Na⁺-sensor was finally fabricated using a printed circuit system, demonstrating the successful measurements of Na⁺ concentrations in various real samples.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.390-390
• /
• 2021

본 연구에서는 통계적 방법에 의해 예측된 미래기간의 기온정보와 기온기반의 기준증발산량 산정방법을 연계하여 한강권역을 대상으로 최대 12개월의 미래기간에 대한 기준증발산량을 전망하였다. 기온정보는 Kim et al. (2020)의 연구와 같이 글로벌 기후지수와의 원격상관성을 기반으로 개발된 다중회귀모형을 이용하여 미래기간(예측시점 기준 1~12개월)에 대해 월 평균기온을 예측하고 이를 상세화하여 한강권역 내 주요 ASOS 지점별로 최고/최저기온을 도출하였다. 기준증발산량은 Hamon 방법(Hamon, 1960, 1963)을 기반으로 각 지점별로 상세화된 최고/최저기온을 이용하여 동일한 미래기간(1~12개월)에 대해 산정하였다. 한강권역 전체에 대해 2015년 1월~2020년 12월의 월별 평균기온과 각 지점별 산정한 기준증발산량을 활용하여 기온 및 기준증발산량에 대한 예측성을 분석하였다. 한강권역 전체에 대해 예측된 월별 평균기온의 경우 실제 관측값과 비교하였을 때, PBIAS 4.2~6.4%, R² 0.97~0.98, NSE 0.97~0.98 등으로 매우 높은 예측성을 보였다. 지점별로 상세화된 기온정보를 이용하여 산정한 기준증발산량을 실제 기온으로부터 산정한 기준증발산량과 비교한 결과는 PBIAS 5.0~6.8%, R² 0.97~0.98, NSE 0.96~0.97로 기온에 대한 예측성과 유사하게 나타났다. 기온과 기준증발산량 모두 일부 월이나 일부 지점에서 관측값과 비교했을 때 다소 차이를 보이는 경우도 있었으나, 대상유역 전반적으로는 매우 안정적인 예측결과를 확인할 수 있었다. 기준증발산량에 대한 예측결과(미래 1~12개월)는 계절 및 월 단위의 유역 수자원 전망에 유용하게 활용될 수 있을 것으로 판단된다.

• The korean journal of orthodontics
• /
• v.28 no.3 s.68
• /
• pp.461-477
• /
• 1998

To evaluate the relapse pattern and long-term stabilities depanding on surgical methods following orthognathic surgery of Cl III patients, the author selected 24 subjects(10 male, 14 female) operated by SSRO and 26 subjects(10 male,16 female) operated by IVRO. Each subject took four lateral cephalograms : just before surgery(T1), within 48hrs after surgery(T2), 4-8 wks after surgery(T3), 6 month or more after surgery(T4), and the landmarks were digitized. The differences of relapse patterns in each interval between two groups were compared and the significance of correlation among the variables of each group was tested. The obtained results are as follows ; 1. Horizontal early relapse was forward movement of mandible in SSRO group, as compared to the backward movement in IVRO group, and there was a statistical significance between the two groups. 2. Vertical early and late relapses were decreases in anterior facial height in both groups and there was no statistical significance between the two groups. 3. There was a statistical significance in negative correlation between mandibular horizontal late relapse and surgical change of articular angle in SSRO group. 4. There was a statistical significance in negative correlation between amount of mandibular set-back and mandibular horizontal early relapse in both groups.

• Korean journal of food and cookery science
• /
• v.26 no.6
• /
• pp.872-886
• /
• 2010

Six kinds of sunsik containing different contents of brown rice(BR; 20, 30, and 50%) were prepared and subjected to various processing conditions(with or without roasting at $200^{\circ}C$ for 20 min e.g., designated as RBR50 or BR50) to assess their functionality as ready-to-eat foods. They were also assessed for their nutritional and sensory properties and oxidative stability. Dietary fiber contents were proportionate to the levels of added BR. Protein was highest in RBR50 (p<0.001), which also had the highest amounts of free and structural amino acids. The amount of free amino acids tended to increase with roasting, although most amino acids were present in structural form. Oleic acid and linoleic acid were the predominant fatty acids in all prepared sunsik, and RBR50 presented noticeably higher peroxidability index due to its higher amount of linoleic acid(p<0.05). Nevertheless, RBR50 showed good oxidative stability; this phenomenon was observed in all sunsik with roasted BR but not in those with non-roasted BR. It is implied that potential antioxidants might have been newly formed or converted from their precursors while BR was roasted. Roasting process also had an impact on the sensory properties of sunsik, e.g., sunsik with added roasted BR showed lower dissolution and darker color intensity compared to its counterpart sunsik.