• Title/Summary/Keyword: Zone

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Zone-melting Process of NdBaCuO Superconductor under Low Oxygen Pressure

  • Soh, Deawha;Zhanguo, Fan;Yingmei, Li
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2004.05a
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    • pp.6-8
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    • 2004
  • The NdBaCuO superconductor samples were zone-melted in low oxygen partial pressure (1 % $O_2$+99%Ar). The zone-melting temperature was decreased about 12$0^{\circ}C$ from 1, 06$0^{\circ}C$, the zone-melting temperature in air. Thus the loss of liquid phase (BaCu $O_2$and CuO) was reduced during the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased and, therefore, the substitution of Nd for Ba was occurred. The superconductivity of zone-melted N $d_{1+x}$B $a_{2-x}$C $u_3$ $O_{y}$prepared under low oxygen partial pressure was distinctively improved.d.d.d.

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A Study on the Behaviour of Plastic Deformation in Weld HAZ of Mild Steel (연강 용접열영향부의 소성변형거동에 관한 연구 1)

  • 박창언;정세희
    • Journal of Welding and Joining
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    • v.7 no.4
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    • pp.38-45
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    • 1989
  • In this study, in order to evaluate the shape and the size of the plastic zone at the notch tip before stable crack growth, a newly developed technique for plastic strain measurement, that is, the recrystallization-etching technique was applied to observe the intense strain zone at the notch tip of weld HAZ. 1) The recrystallized specimens showed that the amount of the intense strain zone, more than 20% plastic zone, was quantitatively observed as the plane strain state during the growth of the plastic zone. 2) The behavior of plastic deformation at midsection are different for parent and weld HAZ. In addition, the micro crack initiation occurs at midsection, parent and weld HAZ when the crack opening displacement(COD) value is .delta.$_{t}$=0.4mm. 3) The plastic zone for parent proceeds in the forward direction at notch tip and for weld HAZ in the right and left direction at the notch tip. 4) The relation between plastic strain energy(Wp) and COD(.delta.$_{t}$) depended on yield stress, gradient and plastic strain size.ize.

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COMPREHENSIVE ASSESSMENT MODEL OF ECOLOGICAL RIPARIAN ZONE

  • Xia, Ji-Hong;Wu, Wei;Yan, Zhong-Min
    • Water Engineering Research
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    • v.6 no.4
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    • pp.169-178
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    • 2005
  • Comprehensive assessment of ecological riparian zone is to analyze and evaluate the status of riparian zone ecosystem. The existing problem of the ecosystem can be found through the assessment. The AHP-FUZZY method used in the assessment is based on the hierarchy model of index, grade model of object, and attribution degree of index. Accordingly, the four models have been discussed and presented from the aspect of the stability, landscape, eco-health and eco-safety of riparian zone.

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A Correlation Concentration of Contaminated Groundwater with Volatilization Coefficient (오염지하수 TCE 농도와 휘발계수와의 관계)

  • 이창수
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2000.11a
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    • pp.266-269
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    • 2000
  • To understand the gaseous behaviour of volatile organic compounds in the unsaturated zone, their volatilization coefficient k$_{Lg}$ is evaluated. An experiment is conducted to examine the dependence of k$_{Lg}$ on the concentration of the dissolution, presence of unsaturated zone and depth of the unsaturated zone. The results show that the volatilization coefficient is not dependent on the concentration under the constant temperature and pressure. It is also find that k$_{Lg}$ depends on the presence of the unsaturated zone rather than its depth.depth.

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The Present State and Problem of Costal Zone Management of Korea (한국 연안관리의 현상과 과제)

  • 박종화;이순혁
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1999.10c
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    • pp.149-154
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    • 1999
  • The objective of this paper is to provide an overview of the coastal zone managment system in the USA , France, Netherlands and Korea with an emphasis on the present state and problem of coastal zone management . Based on each country's experience , environmental techniques and methodologies has provided valuable information that can be used to carry out future , similar enacts laws of caastal zone management . The problem an dthe posture of the costal zone management of Korea are presented and a matter necessary for managing the coast and the problem in the future are presented.

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Secure Implementation of Flash Game Using ARM TrustZone (ARM TrustZone을 이용한 안전한 플래시 게임 구현)

  • Ji-Hyeon Yoon;Ae-Rin Kim
    • Proceedings of the Korea Information Processing Society Conference
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    • 2023.05a
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    • pp.192-193
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    • 2023
  • 게임 산업의 성장에 맞춰 그에 따른 게임시스템 보안, 무결성 보장의 중요성 또한 커지고 있다. 본 논문에서는 게임 시스템과 TrustZone을 결합시켜 TrustZone의 Normal World와 Secure World 영역과 그 기능을 활용하여 게임 내 주요 데이터의 위·변조를 방지하여 시스템의 무결성을 보다 높은 수준에서 보장하는 방식을 탐구해보고자 한다.

Vegetation Distribution of Intertidal Zone and Estuary Area on Anseo Port in Saemangeum Reclamation Zone (새만금 간척지구 내 안서 포구 일대의 식생 분포에 대한 연구)

  • Kim, Eun-Kyu;Jung, Yeong-Sang;Jeong, Hyeung-Geun;Joo, Young-K.;Chun, So-Ul
    • Korean Journal of Environment and Ecology
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    • v.21 no.6
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    • pp.494-505
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    • 2007
  • This study was carried out targeting the intertidal zone and estuary area of Anseo port in Saemangeum reclamation zone from 2003 to 2004, to analyze how reclamation affects the distribution of vegetation and soil properties. The plant growing in these survey areas was all halophytes: the vegetation on the intertidal zone consisted of simply 3 species of halophyte, and vegetation on the high tide zone and estuary area consisted of 9 and 8 species respectively, showing a more varied aspect than the intertidal zone. As for the plant species distribution, the predominant species for the intertidal zone were Suaeda maritima, Limonium tetragonum and Suaeda japonica; the predominant species for the slope zone of estuary were Suaeda maritima, Limonium tetragonum and Aster tripolium, and the predominant species for the inundation zone of estuary were Kochia scoparia var. littorea. At the analysis result of soil chemical properties, it was discovered that the appearance of the plant species was made at some spots on the intertidal zone whose electrical conductivity(EC), $Na^+,\;and\;Cl^-$ were relatively lower. EC of between the plant species was similar in the same zone, however EC was distinctively different between the same species in the different zone. Our study found out that whether the occurrence of the plant species is possible or not was decided by the difference in soil properties. This study results suggest that the distribution of vegetation is influenced by soil environment in that the appearance of the plant species on the intertidal zone and estuary area is differentiated by soil texture and soil chemical properties.

The Characteristics of Foreign and Domestic Coastal Zone Management Indicator System (국내외 연안구역관리 지표체계의 특성)

  • Nam, Kwang-Woo;Oh, Ji-Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.2
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    • pp.885-892
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    • 2012
  • Coastal zone management indicators are being used as an important means of decision making in the process of policy establishment for integrated coastal management and implementation, and these indicators are very useful tools that enable the evaluation of the coastal zone management from an integrated perspective, the understanding and analysis of interactions according to each department. Accordingly, most of organizations in international society and advanced coastal states tend to develop coastal zone management indicator system in order to check current coastal environment, social and economic status, also to grasp effectiveness of the coastal zone management policy. In this research, therefore, the characteristics of coastal zone management indicator system was drawn through understanding of strength and weakness, and conducting comparative analysis of the coastal zone management indicator system according to each level having classified domestic and international coastal zone management indicator system into three aspects at large: natural and environmental aspect; social and economic aspect; and network aspect. As a result, following features were drawn as the common characteristics among the cases in the advanced coastal states: the management means for realization of sustainable coastal zone management; scientific decision making tools for various stakeholders; evaluation means for effectiveness of coastal zone integrated management; and dualization of coastal zone management indicator system; etc. Lastly, based on these common values revealed in the domestic and international coastal management indicator system, a suggestion for correct establishment of the domestic coastal management indicators was proposed in the regional aspect.

Mean viscous drift forces on a fixed vertical cylinder in waves and currents (파랑과 조류에 의한 고정된 수직 실린더 구조물에 작용하는 평균 점성 표류력)

  • Shin, Dong Min;Kim, Yuncheol;Moon, Byung Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.2
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    • pp.521-527
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    • 2020
  • In offshore structures, the mean viscous drift force due to drag is considered to be a design part that has not been considered until recently. In particular, it is most important to calculate the drift force acting on a vertical cylinder considering both waves and currents in the low frequency region. This paper presents a process for deriving analytical solutions for the drift forces acting on a fixed vertical cylinder considering waves and currents. The area of the cylinder was considered by dividing it into a splash zone above the free surface and a submerged zone below the free surface. The presence of waves is considered only in the Splash Zone, and in the case of waves and currents, the equations were obtained for both the splash and submerged zones. The results show that drift forces occur due to the significant viscous effects in both the splash zone and the submerged zone. Therefore, the analytical solutions derived in this study can be used to calculate the drift force using the given design variables and form a theoretical basis for judging whether the magnitude of the drift force in each case has a dominant influence within a specific physical range.