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Damage Evaluation of Bi-directionally Prestressed Concrete Panels under Blast-fire Combined Loading (폭발 후 화재하중 시나리오에 따른 2방향 프리스트레스트 콘크리트 패널부재의 손상도 평가)

  • Choi, Ji-Hun;Choi, Seung-Jai;Kim, Tae-Kyun;Kim, Jang-Ho Jay
    • Journal of the Korea Concrete Institute
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    • v.29 no.3
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    • pp.237-248
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    • 2017
  • Frequent terror or military attack by explosion, impact, fire accidents have occurred recently. These attacks and incidents raised public concerns and anxiety of potential terrorist attacks on important infrastructures. However, structural behavioral researches on prestressed concrete (PSC) infrastructures such as Prestressed Concrete Containment Vessel (PCCV) and Liquefied Natural Gas (LNG) storage tanks under extreme loading are significantly lacking at this time. Also, researches on possible secondary fire scenarios after terror and bomb explosion has not been performed yet. Therefore, a study on PSC structural behavior from an blast-induced fire scenario was undertaken. To evaluate the blast-fire combined resistance capacity and its protective performance of bi-directional unbonded PSC member, blast-fire tests were carried out on $1,400mm{\times}1,000mm{\times}300mm$ PSC specimens. Blast loading tests were performed by the detonation of 25 kg ANFO explosive charge at 1.0 m standoff distance. Also, fire and blast-fire combined loading were tested using RABT fire loading curve. The test results are discussed in detail in the paper. The results can be used as basic research references for related research areas, which include protective design simulation under blast-fire combined loading.

Detail Design and Structural Stability Analysis for Automated PHC Pile Cutting Machine (PHC 파일 원커팅 두부정리 자동화 장비의 상세설계 및 구조적 타당성 분석)

  • Yeom, Dong Jun;Hwang, Ji Young;Park, Yesul;Kim, Young Suk
    • Korean Journal of Construction Engineering and Management
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    • v.19 no.2
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    • pp.117-125
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    • 2018
  • The primary objectives of this study are to develop a detail design of automated PHC pile head cutting machine and structural stability analysis of detail design that improves the conventional head cutting work in safety, quality, and productivity. For this, the following research works are conducted sequentially; 1)literature review and field study, 2)expert survey and interview, 3)selection of core technology using AHP analysis, 4)deduction of detail design 5) verification of structural stability. As an outcome, it is analyzed that gripper and gripper bearing shaft are structurally stable. Their maximum stresses are shown as 15.93%, 10.58% compared to their yield strength respectively. The results of detail design and structural stability analysis in this study will be utilized for the actual development of the automated PHC pile cutting machine prototype.

Effect of Microporous Structure of Al2O3/PVdF_HFP Ceramic Coating Layers on Thermal Stability and Electrochemical Performance of Composite Separators for Lithium-Ion Batteries (Al2O3/PVdF_HFP 세라믹코팅층의 미세기공구조가 리튬이차전지용 복합분리막의 열 안정성 및 전기화학특성에 미치는 영향)

  • Jeong, Hyun-Seok;Kim, Kyu-Chul;Lee, Sang-Young
    • Journal of the Korean Electrochemical Society
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    • v.12 no.4
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    • pp.324-328
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    • 2009
  • The internal short-circuit between cathodes and anodes has been known to be a critical concern for the safety failures of lithium-ion batteries, which is strongly influenced by the thermal stability of separators. In this study, to effectively suppress the internal short-circuit failures, we developed a new composite separator with the improved thermal stability compared to conventional polyolefin-based separators. The composite separators were prepared by introducing a ceramic coating layer ($Al_2O_3$/PVdF-HFP) onto both sides of a polyethylene (PE) separator. The microporous structure of ceramic coating layers is determined by controlling the phase inversion of coating solutions and becomes more developed with the increase of nonsolvent (water) content. This structural change of ceramic coating layers was observed to greatly affect the thermal stability as well as the electrochemical performance of composite separators, which was systematically discussed in terms of phase inversion.

Reseach on Transcultural Nursing (횡문화 간호에 관한 연구)

  • Shin, Kyng-Rim
    • Journal of Korean Academy of Nursing
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    • v.22 no.4
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    • pp.454-463
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    • 1992
  • 세계가 일일 생활권화 됨과 더불어 국제교류가 활발해지므로써 횡문화 간호 연구는 전문직 간호(Professional Nursing)에 있어서 매우 중요한 부분을 차지하고 있음을 많은 문헌을 통해서 알 수 있다(Brink, 1976 : Leininger, 1977 : Roberston & Boyle, 1987). 횡문화 간호연구는 서로 다른 문화적 배경을 가진 사람들을 잘 이해하고 그들의 건강을 돌봄에 있어서 더욱 효과적이고, 안전한 간호를 할 수 있을 뿐만 아니라 간호이론 개발, 간호모형(Model) 개발에 있어서도 매우 중요한 역할을 한다고 믿는다. 본 연구는 1984년에서 1987년 사이에 전문적 간호연구지에 실린 10편의 횡문화 간호연구와 관련된 논문들을 발췌하여 간호지식체의 본질적인 과정인 비판적 문헌고찰을 통해 각 논문들을 비교 분석 한 것으로써, 미래의 간호연구를 위한 간호실무, 간호교육, 간호연구 방법 및 간호 행정면에서 그 적용성을 높여줄 것이다. 비판적 문헌고찰을 위한 기준은 Burns와 Grove(1987)의 방법을 참고하여 아래와 같이 선정하였다. 1. 분석대상 : 목적, 가설 진술, 문헌고찰, 표본조사, 방법론적 논점, 결과 해석 2. 이론적 틀의 유도 흑은 통합 3. 발전적인 간호수행을 위한 중요성, 적용성 및 제언 이상의 내용으로 비교 분석을 해본 결과 1984년에서 1987년 사이에 발표된 횡문화 간호에 관한 논문들의 주제는 주로 여성을 대상으로 한 건강돌봄, 자가간호, 건강신념, 수유, 임신 그리고 간호사와 소수민족 노인과의 의사소통 양상 등으로 나누어 볼 수 있었다. 이론적 틀은 주로 사회학, 정신심리학, 인류학 이론으로부터 도출되었고, 오직 두 편만이 간호 이른에 틀을 둔 것으로 나타났다. 1. 10개의 논문의 가설과 목적의 분석에 있어서 4편의 논문은 목적과 가설이 구체적으로 진술되어 있었고, 나머지 6편은 목적이 전반적으로 진술되어 있었으며 가설도 구체적이지 않았다. 이러한 제한점은 각 논문의 연구자가 문헌고찰을 충분히 하지 못하고 단지 수편의 논문만을 제시 한 데서 비롯되었다고 분석 해 볼 수 있겠다. 2. 문헌고찰 부분에서는 각각의 연구주제를 지지해줄 수 있는 문헌들이 충분히 고찰되지 못하였고, 이론적배경 또한 횡문화 이론과의 관련성이 적었다. 또한 횡 문화 연구에 기초가 되는 연구대상자의 사회 인구학적 특성과 역사적 배경은 잘 나타났으나, 이론적 연구와 경험적 연구 간에 괴리가 있었다. 3. 표본추출방법은 문화에 기반을 둔 대상자를 선정한다는 점에서 한계성 이 있었다. 4. 방법론적 이유로는 대상자와의 면담시간이 구체적으로 기술되지 않았으며, 고유한 언어를 통역하는 과정에서 의미론적 문제에 대한 고려가 부족하였다. 면접과 기록과정에서 보면 자료의 기록과정과 분류 및 분석과정이 명시되어 있지 않았다. 참여관찰과 면접방법을 사용시 이에 대한 자세한 기술이 되어 있지 않았다. 5. 연구결과의 적용 및 이에 대한 논의는 상당히 제한되어 있었는데, 수편의 연구만이 방법론 문제점과 앞으로의 연구분야에 대한 전망을 제시하였으며, 특이한 것은 어 떤 연구자도 이른 개발을 위한 적용 및 임상실무적 차원에서 간호에 대한 제언을 하지 않았다.

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A Critical Review on 'Public Interest' Defense in Libel Litigation (명예훼손 소송의 위법성 조각사유로서의 공익성에 대한 연구)

  • Lee, Jae-Jin;Lee, Sung-Hoon
    • Korean journal of communication and information
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    • v.20
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    • pp.141-176
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    • 2003
  • This paper examined how Korean courts conceptualized and applied public interest defense of Penal Code to the libel cases raised by socially influential persons. For this, this paper analyzed a total of 58 libel cases in which 'public interest' was mentioned by Korean courts between 1981 and 2000. It was found that whereas truth or believed-to-be-true defense is emphasized In libel cases by politicians or public officials, public interest defense was emphasized in the cases by private figures. It was also found that Korean courts tended to think of matters related with 1) national security and social order, 2) prevention of asocial crime, 3) enlightening of public, and 4) protection of consumers' interest as public interest. Conclusively, 'public interest' is not simply applied as an independent legal defense, because Korean courts insistently concentrated on the truth of a story and did not even specifically define what is public interest. Constitution Court recently maintained that the slope of legal defense should be broadened when a story is about public matters. However, Korean courts will not be likely to accept public interest defense as an independent one for the time being.

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The Korea Maritime Security and National Economy (한국의 해양안보와 국가경제)

  • Park, Eung-Soo;Ko, Kwang-Soob
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.1
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    • pp.251-258
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    • 2010
  • The Republic of Korea is the maritime country of which its infrastructure of the country's development is based on maritime trade. This can be easily understood according to degree of dependence upon foreign trade, which is the economic indicator for expressing one country's economic characteristics. In 2008, the degree of dependence upon foreign trade of Korea is 83.5%, and this figure is much higher than that of Japan and China, which is 28.8% and 68% respectively. This in turn means that the development of Korea, and also the security of Korea depends greatly on safety of the sea. On the other hand, there is a growing trend that threats to the maritime security of Korea increases as examples seen in Somalia pirates. Thus we could say that interest on this issue should increase and also measures to counter those threats should be prepared. Also Korea should take the maritime security as important as critical factors as national security, which is similar to military threats from North Korea. Therefore all citizen's interests on the issue should be raised, and organizations that are capable of mutually integrating the functions related to maritime security should be established. Finally, Korea should actively participate international efforts on maritime security, and secure maritime security of our nation therefore contribute to the nation's prosperity and future development.

Seismic Performance Preliminary Evaluation Method of Reinforced Concrete Apartments with Bearing Wall system (기존 철근콘크리트 벽식 공동주택의 내진 성능 예비 평가법에 관한 연구)

  • Chung, Lan;Woo, Sung-Sik;Choi, Ki-Young;Park, Tae-Won
    • Journal of the Korea Concrete Institute
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    • v.19 no.3
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    • pp.293-300
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    • 2007
  • In Korea, the seismic design regulations was established since 1988 about regularity scale of structures. However, It was not established about seismic performance and evaluation method as the most existing buildings was constructed before Earthquake-Resistant Design(1988). In this study, for model structures which are 4 units of non-seismic designed apartment and 3 units of seismic designed in Korea performed seismic performance evaluation by suggested KISTC (2004). And the result compare to evaluate Capacity Spectrum Method by using MIDAS Gen and SDS. As a result, we observed that suggested KISTC's method have overestimated for shear stress and drift index. The purpose of this study provides most conformity seismic performance evaluation process and the appropriate method of calculating the seismic performance index in Korea.

Influence of Modelling Approaches of Diffusion Coefficients on Atmospheric Dispersion Factors (확산계수의 모델링방법이 대기확산인자에 미치는 영향)

  • Hwang, Won Tae;Kim, Eun Han;Jeong, Hae Sun;Jeong, Hyo Joon;Han, Moon Hee
    • Journal of Radiation Protection and Research
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    • v.38 no.2
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    • pp.60-67
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    • 2013
  • A diffusion coefficient is an important parameter in the prediction of atmospheric dispersion using a Gaussian plume model, and its modelling approach varies. In this study, dispersion coefficients recommended by the U. S. Nuclear Regulatory Commission's (U. S. NRC's) regulatory guide and the Canadian Nuclear Safety Commission's (CNSC's) regulatory guide, and used in probabilistic accident consequence analysis codes MACCS and MACCS2 have been investigated. Based on the atmospheric dispersion model for a hypothetical accidental release recommended by the U. S. NRC, its influence to atmospheric dispersion factor was discussed. It was found that diffusion coefficients are basically predicted from a Pasquill- Gifford curve, but various curve fitting equations are recommended or used. A lateral dispersion coefficient is corrected with consideration for the additional spread due to plume meandering in all models, however its modelling approach showed a distinctive difference. Moreover, a vertical dispersion coefficient is corrected with consideration for the additional plume spread due to surface roughness in all models, except for the U. S. NRC's recommendation. For a specified surface roughness, the atmospheric dispersion factors showed differences up to approximately 4 times depending on the modelling approach of a dispersion coefficient. For the same model, the atmospheric dispersion factors showed differences by 2 to 3 times depending on surface roughness.

A Study on Reliability Based Design Criteria for the Steel Highway Bridge (강도로교(鋼道路橋)의 신뢰성(信賴性) 설계규준(設計規準)에 관한 연구(硏究))

  • Cho, Hyo Nam;Kim, Woo Seok;Lee, Cheung Bin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.5 no.1
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    • pp.43-53
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    • 1985
  • This study proposes a reliability based design criteria for the steel bridge (H-beam, plate-girder and composite-beam), which is most common type of steel bridge, and also proposes the theoretical bases of nominal safety factors as well as load and rasistance factors based on the reliability theory. Major 2nd moment reliability analysis and design theories including both Cornell's MFOSM (Mean First Order 2nd Moment) Methods and Lind-Hasofer's AFOSM(Advanced First Order 2nd Moment) Methods are summarized and compared, and it has been found that Lind-Hasofer's approximate and an approximate Log-normal type reliability formula are well suited for the proposed reliability study. A target reliability index (${\beta}_0=3.5$) is selected as an optimal value considering our practice based on the calibration with the safety pravisions of the current steel bridge design code. Galambo's theory is used for the derivation of the algorithm for the evaluation of uncertainties associated with resistences by LRFD Format and SGST Format, whereas the magnitude of the uncertainties associated with load effects are chosen primarily by considering our level of practice. It may be concluded that the proposed LRFD reliability based design provisions for the steel highway bridge give more rational design than the current standard code for steel highway bridge.

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400 MeV/nucleon 12C Ions Shielding Benchmark Calculations using MCNPX with Different Nuclear Data Libraries (400 MeV/nucleon 12C 이온의 MCNPX 와 핵자료를 이용한 차폐 벤치마킹 계산)

  • Shin, Yun Sung;Kim, yong min;Kim, dong hyun;Jung, nam suk;Lee, hee seock
    • Journal of the Korean Society of Radiology
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    • v.9 no.5
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    • pp.295-300
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    • 2015
  • There are various type of particle accelerators such as Kyoungju 100-MeV proton beam accelerator in Korea. And Korea plans to build large particle accelerator such as heavy ion accelerator and 4th generation light source facility. The accelerated high energy particles of these facility produce 2nd neutron after nuclear reaction with target materials. And then these 2nd neutron activate structural materials and surrounding environment. Accordingly, it is important to consider the activation and shielding calculation on design of facility for safety operation. In this study, we tried to calculate and compare the neutron flux from the interaction $^{la}150$ beam with target material(Cu) according to thickness of iron and concrete shielding material by MCNPX 2.7 with nuclear library JENDL/HE 07and la150. To verify the properties of nuclear library, we compared computational results with experimental value. These results can be used for dose evaluation technology in planning of the shielding of large particle accelerator.