• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.2
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• pp.208-215
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• 1992

Concept of primary solidification mode control was adopted to obtain optimal solidification crack resistance, hot ductility, corrosion resistance and toughness for austenitic stainless steel. By controlling primary solidification phase as primary $\delta$ and containing no ferrite at room temperature, optimal solidification crack resistance, hot ductility, corrosion resistance and cryogenic toughness could be obtained. The optimum chemical composition of austenitic stainless steel ranges 1.46~1.55(Creq/Nieq ratio) calculated by Schaeffler's equation.

• Journal of Korea Foundry Society
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• v.29 no.4
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• pp.160-164
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• 2009

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.5B
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• pp.623-631
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• 2001

본 논문에서는 등간격 선형어레이로 입사한 인코히어런트신호의 도래각을 추정하기 위하여 행렬특성매핑을 기본으로 한 알고리듬을 제안한다. 알로리듬의 기본 개념은 공분산 행렬 초정값과 Frobenius norm 면에서 가장 가까운 공분산 행렬 (혹은 스펙트럼 밀도행렬)을 찾는 것이다. 제안된 알고리듬의 우수한 성능을 보여주기 위하여 협대역 신호인 경우에는 MUSIC과 광대역 신호인 경우에는 CSM-MUSIC과 컴퓨터 시뮬레이션을 통하여 통계적 성능을 비교하였다.

• The Optical Journal
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• s.141
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• pp.28-29
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• 2012

한국광학기기산업협회가 지난 8월 23일 서울 방배동 소재 함지박 별관에서 '광분야 R&D 로드맵 관련 지식경제부 초청 간담회'를 개최했다. 이번 간담회에는 지식경제부 전자산업과에서 LED 및 광분야의 국가 로드맵을 담당하고 있는 오대곤 프로젝트 디렉터(PD)를 비롯해 20여 명의 한국광학기기산업협회 회원사 대표 및 관계자들이 참석해 국내외 광산업에 대한 다양한 의견을 나눴다.

• Fire Protection Technology
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• s.25
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• pp.3-4
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• 1998

오래전부터 선진외국의 방재산업분야는 UL(미국), LPCB(영국), Vds(독일) 등의 민간전문기관에 의한 품질인증제도를 통하여 상품의 품질향상과 기술개발을 추구해 오고 있다. 특히, WTO체제 출범에 따른 세계 시장개방과 관련하여 국내에서 생산되는 모든 상품이 대외 경쟁력을 갖기 위해서는 국제기준에 의한 품질인증제도의 도입이 필수적이다. 그러나, 국내에서는 민간단체에 의한 자율적인 품질인증제도의 활동이 널리 알려져 있지 않는 실정에 있다. 이에 방재시험연구소에서는 국내 품질인증제도의 발전과 아울러 민간단체 인증제도의 활성화 방안을 모색하고자 FILK인증업체 초청 간담회를 개최하였다.

• Transactions of Materials Processing
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• v.13 no.7
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• pp.608-613
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• 2004

Mechanical properties of hypereutectic Al-Si alloy are influenced by the size and distribution of primary Si. To investigate the effects of P addition and holding time, hypereutectic Al-Si alloys with various amount of P content were produced in the lab. Then, the size and distribution of primary Si were examined respectively. Mechanical properties of hardness, tensile strength and wear resistance were analyzed in conjunction with the microstructural variations in alloys.

• Composites Research
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• v.14 no.5
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• pp.1-11
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• 2001

The particulates reinforced metal matrix composites(PMMC) have a number of interesting mechanical properties. including high strength and good resistance to wear at high temperature and low thermal expansion. The equipment structure to obtain the homogeneous distribution in composites are proposed for the continuous pouring of reinforcement at the desired temperature. The particulates reinforced metal matrix composites(A357/SiCp) were fabricated by the process of the combined stirring method with the various fabrication process. The combined stirring method to niform distribution of particle is consisted of two stirring force both electro-magnetic stirring generated from induction heating and mechanical stirring with graphite stirrer. PMMC billets were fabricated with the volume fractions ranged from 0% to 20% and particle sizes ranged from 14${\mu}{\textrm}{m}$ to 25${\mu}{\textrm}{m}$. It is important to cont the size of primary $\alpha$-Al solid particles because it could become the cause of the particle pushing or capture phenomena from the fact that secondary dendrite arm spacing size depends on the cooling rate during the solidification in hypoeutectic Al-Si alloy. Therefore, the effect of primary $\alpha$-Al on the reinforcement distribution in matrix alloys has been investigated. The microstructure of PMMC fabracated with various volume fractions(0%, 10%, and 20%) and particle size were observed.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.517-523
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• 2007

Geophysical surveys(seismic refraction, electrical resistivity, and ground penetrating radar) were performed to delineate the weathering zone associated with vadose water in Chojeong area and investigate the fault related fracture zones. On the basis of seismic velocity structures, weathering layer for the southwestern part is interpreted to be deeper than for the northeastern part. The depth to bedrock(i.e., thickness of weathered zone) from seismic refraction data attempted to be correlated with drill-core data and groundwater level. As for the investigation of geological discontinuities such as fault related fracture zone, seismic refraction, electrical resistivity, and ground penetrating data are compositely employed in terms of velocity and resistivity structures for mapping of surface boundary of the discontinuities up to shallow depth. Surface boundaries of fracture zone are well indicated in seismic velocity and electrical resistivity structures. Accurate estimation of weathered zone and fracture zone can be successfully available for mapping of attitude of vadose water layer.

• Korean Journal of Comparative Education
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• v.22 no.4
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• pp.75-98
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• 2012

This study aims to investigate and compare with each other the global scholarship policy of Korea, China, and Japan, which is supported by government, and to suggest the improvement plan of the Global Korea Scholarship(GKS) program in Korea. Based on the results of comparison study with Chinese and Japanese policies, the implications for GKS program are as follows. First, GKS program needs to be redesigned according to the boundaries of in-bound and out-bound countries. Especially, the GKS program for 'neighboring countries' focusing on East Asian countries, could be developed as the Union of East Asian Nations. Second, to maximize the performance of GKS, the government needs to cooperate more actively and systematically among related departments through all the steps as a national foreign policy, that is, from establishing goals to evaluating performance. Third, the perspectives on GKS must be expanded, not just as a kind of scholarship, but as a policy for developing Korean culture and language. Fourth, out-bound GKS programs must be greatly expanded in relation to short-term programs as well as the quality of in-bound GKS programs. Finally, out-bound GKS programs for the Asian developing countries need to be redesigned and operated under the focus of ODA, to support the invited Parties beyond the foreign resource policy.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.4
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• pp.171-179
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• 1999

The $CO_2$-rich waters in the Chojeong area are characterized by low pH (5.0~5.8), high $CO_2$pressure (about 1 atm) and high amounts of total dissolved iou (up to 989 mg/L) and chemically belong to Ca-HC $O_3$type. The oxygen. deuterium and tritium isotope data indicate that the mixing process occurred between $CO_2$-rich water and surface water and/or shallow groundwaters and also suggest that the $CO_2$-rich water has been derived from meteoric waters. According to $\delta$$^{13}$ C values (-8.6~-5.3$\textperthousand$). the $CO_2$ in the water is attributed from deep seated $CO_2$gas. The high dissolved carbon (-14.4~-6.8$\textperthousand$. $\delta$$^{13}$ C) in groundwater of the granitic terrain might be affected by $CO_2$-rich water, whereas the dissolved carbon (-17.9~-15.2$\textperthousand$. $\delta$$^{13}$ C) in groundwater of the metamorphic terrain is likely controlled by soil $CO_2$ and from the reaction with calcite in phyllite. Sulfur isotope data (＋3.5~＋11.3$\textperthousand$,$\delta$$^{34}$ $S_{SO4}$) also support the mixing process between $CO_2$-rich water and shallow groundwater. Strontium isotopic ratio ($^{87}$ Sr/$^{86}$ Sr) indicates that the $CO_2$-rich water (0.7138~0.7156) is not related to vein calcite (0.7184) of Buak mine or calcite (0.7281~0.7346) in phyllite. By nitrogen isotope ($\delta$$^{15}$ $N_{NO3}$) the sources of nitrogen (up to 55.0 mg/L, N $O_3$) in the $CO_2$-rich water are identified as fertilizer and animal manure. It also indicates the possibility of denitrification during the circulation of nitrogen in the Chojeong area. The possible evolution model of the $CO_2$-rich water based on the hydrochemical and environmental isotopic data was proposed in this study. The $CO_2$-rich waters from the Chojeong area were primarily derived from the reaction with granite by supply of deep seated $CO_2$. and then the $CO_2$-rich water was mixed and diluted with the local groundwater.ter.