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- 저자 : Jaeyeong Jang (검색결과 37 건)
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Jaeyeong Jang,Giyoon Kim,Sanggeol Jeong,Heejun Chung,Myungsoo Kim 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1
Our research team has developed a gamma ray detector which can be distributed over large area through air transport. Multiple detectors (9 devices per 1 set) are distributed to measure environmental radiation, and information such as the activity and location of the radiation source can be inferred using the measured data. Generally, radiation is usually measured by pointing the detector towards the radioactive sources for efficient measurement. However, the detector developed in this study is placed on the ground by dropping from the drone. Thus, it does not always face toward the radiation source. Also, since it is a remote measurement system, the user cannot know the angle information between the source and detector. Without the angle information, it is impossible to correct the measured value. The most problematic feature is when the backside of the detector (opposite of the scintillator) faces the radiation source. It was confirmed that the measurement value decreased by approximately 50% when the backside of the detector was facing towards the radiation source. To calibrate the measured value, we need the information that can indicate which part of the detector (front, side, back) faces the source. Therefore, in this study, we installed a small gamma sensor on the backside of the detector to find the direction of the detector. Since this sensor has different measurement specifications from the main sensor in terms of the area, type, efficiency and measurement method, the measured values between the two sensors are different. Therefore, we only extract approximate direction using the variation in the measured value ratio of the two sensors. In this study, to verify the applicability of the detector structure and measurement method, the ratio of measured values that change according to the direction of the source was investigated through MCNP simulation. The radioactive source was Cs-137, and the simulation was performed while moving in a semicircular shape with 15 degree steps from 0 degree to 180 degrees at a distance of 20 cm from the center point of the main sensor. Since the MCNP result indicates the probability of generating a pulse for one photon, this value was calculated based on 88.6 μCi to obtain an actual count. Through the ratio of the count values of the two sensors, it was determined whether the radioactive source was located in the front, side, or back of the probe.
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Jaeyeong Jang,Hyun Young Kim 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1
With the introduction and implementation of the National Research and Development Innovation Act in 2021, researchers are required to have a greater understanding of research ethics and to comply more strictly. The range of misconduct in research and the standards for sanctions have been expanded with the introduction of the National Research and Development Innovation Act. In addition, researchperforming institutions and specialized agencies have been obligated to establish their own research management systems and standards according to the changed criteria. The Korea Institute of Nuclear Nonproliferation and Control (KINAC), a nuclear regulatory authority that is conducting national R&D in related fields, has sought to strengthen research ethics by revising related regulations, introducing a plagiarism detection system, and expanding related education in accordance with these policies. In this study, we analyzed the effectiveness of the plagiarism detection system as a basic quality control measure for research results and a tool for enhancing research ethics, which was introduced. KINAC did not simply introduce a plagiarism detection program but established institutional improvements and other regulatory measures to support it, with the aim of more effectively managing research results. To analyze the effectiveness of this system, we calculated the plagiarism rate by sampling 30 papers each year for the three years before the introduction of the plagiarism detection system. When comparing the plagiarism rates before and after the introduction of the plagiarism detection system, no exceptional cases of high plagiarism rates were found in papers published after the introduction of the system. Although most of the papers before the introduction of the system showed a satisfactory plagiarism rate, some cases showed high plagiarism rates. We analyzed the cause of such cases in detail. Some exceptional cases were also found to be included in the range of misconduct regulated by the National Research and Development Innovation Act. As no such cases were found after the introduction of the system, we could infer that the system is effectively functioning as a tool for basic quality control and enhancing research ethics. In the future, we plan to expand the sample qualitatively and quantitatively by including other forms of outcomes published by the institution, not just papers, and conduct a more detailed analysis. Based on the results, we will develop various improvement plans for enhancing the quality and research ethics of the institution’s research results.
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Study on Measures to Improve the Quality of Nuclear Regulation by Regulatory Authority
Jaeyeong Jang 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2
In Korea, nuclear regulation is supervised by the Nuclear Safety and Security Commission (NSSC). The area that required expertise in regulatory activities has been entrusted to the Korea Institute of Nuclear Safety (KINS) and the Korea Institute of Nuclear Nonproliferation and Control (KINAC) affiliated to the NSSC. Such nuclear regulatory activities should be implemented fairly and objectively because they directly affect nuclear operators and the entire nuclear industry. In addition, as the recent policy trend has flowed in the direction of improving the business efficiency and quality of public institutions, a study was intended to improve the overall regulatory quality of the institution. First, a case study was performed on the quality management system of domestic and foreign related organizations, including the Department of Energy (DOE) and the Nuclear Regulatory Commission (NRC) in the US. Through study and analysis of the system, it was attempted to derive institutional quality requirements for KINAC and to establish a plan to use the requirements as major items of Internal Quality Control (IQC) system. By analyzing the quality management systems of research institutes such as Brookhaven National Laboratory (BNL) and Electronics and Telecommunications Research Institute (ETRI) as well as regulatory authority, the characteristics of KINAC that conduct R&D necessary for regulation were reflected. Based on this study, the quality management system leading to IQC-EQA (External Quality Assurance) -TQM (Total Quality Management) will be established continuously to improve the business quality of regulatory authority.
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Feasibility Study of Beta Detector for Small Leak Detection inside the Reactor Containment
Jang, JaeYeong,Schaarschmidt, Thomas,Kim, Yong Kyun The Korean Association for Radiation Protection 2018 방사선방어학회지 Vol.43 No.4
Background: To prevent small leakage accidents, a real-time and direct detection system for small leaks with a detection limit below that of existing systems, e.g. $0.5gpm{\cdot}hr^{-1}$, is required. In this study, a small-size beta detector, which can be installed inside the reactor containment (CT) building and detect small leaks directly, was suggested and its feasibility was evaluated using MCNPX simulation. Materials and Methods: A target nuclide was selected through analysis of radiation from radionuclides in the reactor coolant system (RCS) and the spectrum was obtained via a silicon detector simulated in MCNPX. A window was designed to reduce the background signal caused by other nuclides. The sensitivity of the detector was also estimated, and its shielding designed for installation inside the reactor CT. Results and Discussion: The beta and gamma spectrum of the silicon detector showed a negligible gamma signal but it also contained an undesired peak at 0.22 MeV due to other nuclides, not the $^{16}N$ target nuclide. Window to remove the peak was derived as 0.4 mm for beryllium. The sensitivity of silicon beta detector with a beryllium window of 1.7 mm thickness was derived as $5.172{\times}10^{-6}{\mu}Ci{\cdot}cc^{-1}$. In addition, the specification of the shielding was evaluated through simulations, and the results showed that the integrity of the silicon detector can be maintained with lead shielding of 3 cm (<15 kg). This is a very small amount compared to the specifications of the lead shielding (600 kg) required for installation of $^{16}N$ gamma detector in inside reactor CT, it was determined that beta detector would have a distinct advantage in terms of miniaturization. Conclusion: The feasibility of the beta detector was evaluated for installation inside the reactor CT to detect small leaks below $0.5gpm{\cdot}hr^{-1}$. In future, the design will be optimized on specific data.
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Jang, Kuewhan,You, Juneseok,Park, Chanhoo,Park, Hyunjun,Choi, Jaeyeong,Choi, Chang-Hwan,Park, Jinsung,Lee, Howon,Na, Sungsoo IOP 2016 Nanotechnology Vol.27 No.36
<P>Recent advancements of nanomaterials have inspired numerous scientific and industrial applications. Zinc oxide nanowires (ZnO NWs) is one of the most important nanomaterials due to their extraordinary properties. However, studies performed over the past decade have reported toxicity of ZnO NWs. Therefore, there has been increasing demand for effective detection of ZnO NWs. In this study, we propose a method for the detection of ZnO NW using a quartz crystal microbalance (QCM) and DNA probes. The detection method is based on the covalent interaction between ZnO NWs and the phosphoric acid group of single-stranded DNA (i.e., linker DNA), and DNA hybridization between the linker DNA and the probe DNA strand on the QCM electrode. Rapid, high sensitivity, <I>in situ</I> detection of ZnO NWs was demonstrated for the first time. The limit of detection was 10<SUP>−4</SUP> <I>μ</I>g ml<SUP>−1</SUP> in deionized water, which represents a sensitivity that is 100000 times higher than the toxic ZnO NW concentration level. Moreover, the selectivity of the ZnO NW detection method was demonstrated by comparison with other types of nanowires and the method was able to detect ZnO NWs in tap water sensitively even after stored for 14 d in a refrigerator. The performance of our proposed method was sufficient to achieve detection of ZnO NW in the ‘real-world’ environment.</P>
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Jang, Kuewhan,Park, Chanho,You, Juneseok,Choi, Jaeyeong,Park, Hyunjun,Park, Jinsung,Lee, Howon,Choi, Chang-Hwan,Na, Sungsoo IOP 2016 Nanotechnology Vol.27 No.47
<P>For several decades, silver nanomaterials (AgNMs) have been used in?various research areas?and commercial products. Among the?many AgNMs, silver nanowires (AgNWs) are one of the mostly?widely used nanomaterials due to their?high electrical and thermal conductivity. However, recent studies have investigated the toxicity of AgNWs. For this reason, it is necessary to develop a successful detection method of AgNWs for protecting human health. In this study, label-free, highly sensitive, direct, and real-time detection of AgNWs is performed for the first time. The detection mechanism is based on the resonance frequency shift upon the mass change from the hybridization between the probe DNA on the electrode and the linker DNA attached on AgNWs. The frequency shift is measured by using a quartz crystal microbalance. We are able to detect 1 ng ml<SUP>−1</SUP> of AgNWs in deionized water in real-time. Moreover, our detection method can selectively detect AgNWs among other types of one-dimensional nanomaterials and can also be applied to detection in drinking water.</P>
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Park Jaeyeong,Kim Taehee,Muhammad Buhari Lawan,Ki Jang-Seu 한국미생물학회 2023 The journal of microbiology Vol.61 No.6
Ship biofouling is one of the main vectors for the introduction and global spread of non-indigenous organisms. Diatoms were the early colonizers of ship hulls; however, their community composition on ships is poorly understood. Herein, we investigated the diatom community on the hull samples collected from two Korean research vessels Isabu (IRV) and Onnuri (ORV) on September 2 and November 10, 2021, respectively. IRV showed low cell density (345 cells/cm2) compared to ORV (778 cells/cm2). We morphologically identified more than 15 species of diatoms from the two research vessels (RVs). The microalgae in both RVs were identified as Amphora, Cymbella, Caloneis, Halamphora, Navicula, Nitzschia, and Plagiogramma. Of them, the genus Halamphora was found to be predominant. However, both RVs had a varied dominant species with a significant difference in body size; Halamphora oceanica dominated at IRV, and Halamphora sp. at ORV, respectively. Molecular cloning showed similar results to morphological analysis, in which Halamphora species dominated in both RVs. The hull-attached species were distinct from species found in the water column. These results revealed diatoms communities that are associated with ship hull-fouling at an early stage of biofilm formation. Moreover, ships arriving from different regions could show some variation in species composition on their hull surfaces, with the potential for nonindigenous species introduction.
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