• Environmental Analysis Health and Toxicology
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• 제31권
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• pp.2.1-2.4
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• 2016

Objectives In this study, we investigated the biodegradation features of 4 perfluorooctanesulfonate (PFOS) alternatives developed at Changwon National University compared to those of PFOS. Methods Biodegradation testing was performed with microorganisms cultured in the good laboratory practice laboratory of the Korea Environment Corporation for 28 days following the Organization for Economic Cooperation and Development guidelines for the testing of chemicals (Test No. 301 C). Results While $C_8F_{17}SO_3Na$, PFOS sodium salt was not degraded after 28 days, the 4 alternatives were biodegraded at the rates of 20.9% for $C_{15}F_9H_{21}S_2O_8Na_2$, 8.4% for $C_{17}F_9H_{25}S_2O_8Na_2$, 22.6% for $C_{23}F_{18}H_{28}S_2O_8Na_2$, and 23.6% for $C_{25}F_{17}H_{32}O_{13}S_3Na_3$. Conclusions $C_{25}F_{17}H_{32}S_3O_{13}Na_3$, $C_{23}F_{18}H_{28}S_2O_8Na_2$, and $C_{15}F_9H_{21}S_2O_8Na_2$ were superior to PFOS in terms of biodegradation rates and surface tension, and thus they were considered highly applicable as PFOS alternatives. Environmental toxicity, human toxicity, and economic feasibility of these compounds should be investigated prior to their commercialization.

• 전기전자학회논문지
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• 제20권2호
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• pp.177-180
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• 2016

본 연구에서는 4H-SiC(0001)기판 위에서 형성되는 나노구조화를 제어하기 위해 상지층과 하지층으로 구성된 이중층 금속을 증착하고 두께, 열처리 시간을 변화하였다. 또한 표면에너지와 응집현상의 상관관계를 분석하기 위해 SiC와는 다른 표면에너지를 갖는 Glass와 Si기판에도 같은 조건으로 실험하였다. FE-SEM을 통하여 금속이 나노구조화를 형성하는 두께가 Ag=20nm, Ti=2nm임을 확인 했으며 두께가 두꺼울 수록 나노 입자가 형성되지 않았다. 세기판의 표면에너지를 구하기 위해 접촉각 측정기를 통해 정접촉각법으로 측정하였다. 그 결과 표면에너지 값이 가장 높은 Glass(53.89 mN/m) 기판에서 나노 입자가 가장 고르게 분포된 형태를 보였으며 SiC(41.13 mN/m)에서 나노구조화 되는 양상을 보였고, Si(32.96 mN/m)에서는 NPs 형성이 되지 않았다. 표면에너지가 작을수록 나노 입자형성이 고르게 분포되는 현상을 Young equation으로 분석하였다.

• 한국해양공학회지
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• 제15권3호
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• pp.120-127
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• 2001

The potential pollution problems resulting from tanker collision necessitate the requirement for an effective structural design and the development of relevant safety regulations. During a few decades, the great effort has been made by the international Maritime Organization and the Administration, etc, to reduce oil spillage from collision accidents. However there is still a need for investigation in the light of structural evaluation method for the experiments and rational analysis, and design development for an operational purpose of ships. This study aims for investigating a complicated structural response of bow structures of simplified models and oil carriers for assessing the energy dissipation and crushing mechanics of the striking vessels through a methodology of the numerical analysis for the various models and its design changes. Through these study an optimal bow construction absorbing great portion of kinetic energy at the least penetration depth prior to reach to the cargo area and an effective location of collision bulkhead are investigated. In order to obtain a rational results in this study, three stages of collision simulation procedures have been performed step by step as follows; 1) 16 simplified ship models are used to investigate the structural response against bow collision with variation of primary and secondary members. Mass and speed are also varied in four conditions. 2) 21 models consisted of 5 sizes of the full scaled oil carriers are used to perform the collision simulation with the various sizes and deadweight delivered in a recent which are complied with SOLAS and MARPOL. 3) 36 models of 100l oil carrier are used to investigate the structural response and its influence to the collision bulkhead against bow collision in variation with location of collision bulkhead, primary members, framing system and colliding conditions, etc. By the first study using simplified models the response of the bow collision is synthetically evaluated for the parameters influencing to the absorbed energy, penetration depth and impact force, etc.

• 에너지공학
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• 제21권1호
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• pp.1-17
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• 2012

원자력 인력 고령화는 원전 수출에 따른 새로운 인력 수요 증가에 못지 않는 중요한 인력 문제를 야기할 수 있다. 고령화된 숙련 전문인력의 대거 퇴직에 따른 고급 인력난과 원자력 기술능력 약화는 한국 원자력의 경쟁력을 크게 약화시킬 수 있다. 본 연구는 한국 원자력 관련 기관 및 업체들에 대해 2001년과 2010년 국내원자력 기관의 인력 현황에 대한 통계조사에 근거하여 약 10년의 기간 동안 원자력 인력 변동 추이 등의 인력 현황 통계자료를 활용했다. 이를 토대로 조사대상 기관별로 그리고 통합적으로 원자력 인력의 고령화 수준을 검토한다. 그리고 원자력 인력 고령화 문제에 대비하기 위한 인력 충원의 방향과 한국 원자력 인력 수급의 문제점을 해소해 나가기 위한 대응방안을 제시할 것이다.

• 디지털융복합연구
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• 제12권7호
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• pp.85-93
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• 2014

본 연구는 최근 급격히 늘어난 국내 원전 보도의 불균형성에 대한 비판을 문제의식으로 하여 원전에 대한 정보를 직접적으로 얻는 유관기관 종사자들과 심층인터뷰를 통해 국내 원전 보도에 대하여 어떻게 인식하고 있는지 파악했다. 원전에 대한 논의에서 당사자적 입장을 갖는 이들은 원전보도가 원자력에 대한 부정적 측면만 편중보도하고 있으며, 위험에 대해서만 과장되고 왜곡된 보도를, 전문지식의 부족으로 원전에 대한 몰이해를 유발하고 있다고 인식하고 있었다. '원전 비리' 사건에 대해서는 더욱 철저히 파헤쳐야 한다고 인식하고 있었다. 이로서 선정적이고 위협적 소구에 편중된 프레임을 초월하는 균형 잡힌 원전보도를 위해 저널리즘적 성찰과 경계에서 나아가 과학적 전문 지식의 점검, 에너지 영역 전문 기자 양성 등 과학보도에 대한 정책적 변화의 필요성을 촉구했다.

• 대한조선학회논문집
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• 제52권6호
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• pp.471-477
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• 2015

When a ship sails in a seaway, the resistance on a ship increases due to incident waves and winds. The magnitude of added resistance amounts to about 15–30% of a calm-water resistance. An accurate prediction of added resistance in waves, therefore, is essential to evaluate the performance of a ship in a real sea state and to design an optimum hull form from the viewpoint of the International Maritime Organization (IMO) regulations such as Energy Efficiency Design Index (EEDI) and Energy Efficiency Operational Indicator (EEOI). The present study considers added resistance problem of AFRAMAX-class tankers with the conventional bow and Ax-bow shapes. Added resistance due to waves is successfully calculated using 1) a three-dimensional time-domain seakeeping computations based on a Rankine panel method (three-dimensional panel) and 2) a commercial CFD program (STAR-CCM+). In the hydrodynamic computations of a three-dimensional panel method, geometric nonlinearity is accounted for in Froude-Krylov and restoring forces using simple wave corrections over exact wet hull surface of the tankers. Furthermore, a CFD program is applied by performing fully nonlinear computation without using an analytical formula for added resistance or empirical values for the viscous effect. Numerical computations are validated through four degree-of-freedom model-scale seakeeping experiments in regular head waves at the deep towing tank of Hyundai Heavy Industries.

• 한국재료학회지
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• 제15권6호
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• pp.361-369
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• 2005

InP(100) crystal surface was irradiated by ion beams with low energy $(180\~225\;eV)$ and high flux $(\~10^{15}/cm^2/s)$, Self-organization process induced by ion beam was investigated by examining nano structures formed during ion beam sputtering. As an ion source, an electrostatic closed electron Hall drift thruster with a broad beam size was used. While the incident angle $(\theta)$, ion flux (J), and ion fluence $(\phi)$ were changed and InP crystal was rotated, cone-like, ripple, and anistropic nanostrucuture formed on the surface were analyzed by an atomic force microscope. The wavelength of the ripple is about 40 nm smaller than ever reported values and depends on the ion flux as $\lambda{\propto}J^{-1/2}$, which is coincident with the B-H model. As the incident angle is varied, the root mean square of the surface roughness slightly increases up to the critical angle but suddenly decreases due to the decrease of sputtering yield. By the rotation of the sample, the formation of nano dots with the size of $95\~260\;nm$ is clearly observed.

• Journal of Radiation Protection and Research
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• 제20권2호
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• pp.129-136
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• 1995

중저준위 에너지 범위에서 방사선관리용측정기기의 에너지의존성에 대한 연구를 위하여 ISO에서 는 ISO표준 X선장을 발간하였으며, 또한 ANSI에서도 개인방사선측정 기기의 성능시험을 위하여 ANSI X선장을 제시 하였다. 그러나 X선 스펙트럼의 측정은 많은 시간이 소요될 뿐만 아니라 특히 측정 X선 스펙트럼에 unfolding이 수행된다면 매우 어려운 작업이 된다. 따라서 이론적인 방법에 의해 스펙트럼을 계산 예측하고 그 평균에너지 및 선량환산인자를 계산하는 것은 X선 실험제작에 필요한 시간, 노력 및 비용을 최소화 할 수 있을 것이다. 따라서 본 연구에서는 ISO Narrow series 및 ANSI X선장에 대하여 이론적으로 스펙트럼을 계산하였으며, 그에 의한 평균에너지와 선량당량혼산인자를 계산하였다. 본 계산에 의한 평균에너지 및 선량환산인자는 측정스펙트럼에 의한 ISO 및 X선장의 값과 잘 일치하였다.

• 대한안전경영과학회지
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• 제17권3호
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• pp.97-104
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• 2015

The study is conducted in order to identify whether there is difference in laboratory safety management committee and safety manager appointment for type of institutes(university, research institute, enterprise institute). The study conducted statistical analysis of 2484 institutes (university, research institute, enterprise institute) that attended 'current status of laboratory safety management' by year(number of current status participation). As a result, university showed increase in forming safety management committee as the number of current status(year) increases. The number of safety management committee held were the highest amongst all institutes being 2 held/2 year. Furthermore, period of safety management committee held at university and research institutes are decreasing stately. For 2014, the rate of hosting periodic committee and temporary committee simultaneously when necessary are increasing. The rate of appointing safety manager who is in charge of laboratory safety is increasing in university, but it is decreasing in research institute and enterprise institute. The work pattern of safety manager in university is increase in exclusive duties and decrease in adjunct duties, while work pattern in research institute and enterprise institute is more on the contract duties.

• 대한의생명과학회지
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• 제28권4호
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• pp.334-339
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• 2022

African swine fever virus (ASFV) is a highly contagious and lethal pathogen that poses a threat to the global pork industry. The World Organization for Animal Health (WOAH) has placed strict surveillance measures for ASFV. The possibility of long-term survival of ASFV in raw meat or undercooked pork has been reported. Accordingly, the problem of secondary infection in food waste from households or waste disposal facilities has emerged, raising the need for ASFV monitoring of food waste. However, most of the previously reported ASFV gene detection methods are focused on clinical monitoring of pigs. There are very few cases in which their application in waste has been verified. Since ASFV diagnosis requires rapid monitoring and immediate action, loop-mediated isothermal amplification (LAMP) may be suitable, but this requires conformity assessment for LAMP to be used as a diagnostic technique. In this study, six LAMP methods were evaluated, and two methods (kit and manual) were recommended for use in diagnosing ASFV in food waste.