Size dependence of metal-insulator transition in stoichiometric Fe₃O₄ nanocrystals

Jisoo LEE,Soon Gu KWON,Je-Geun PARK,Taeghwan HYEON 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

Retinal findings and risk factors of preeclampsia-associated retinopathy: A retrospective cohort study

( Jisoo Kim ),( Dae Gwan Kwon ),( Seokyung Kim ),( Jeong In Yang ),( Ji Hun Song ),( Dong Wook Kwak ) 대한산부인과학회 2023 대한산부인과학회 학술대회 Vol.109 No.-

A Study on Representative Sampling Plan for Spent Filters in Radioactive Waste Drums

Jisoo Yoon,Kyung Rock Park,Jung-Kwon Son 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

Spent filters contained in drums of radioactive waste generated from nuclear power plants are contaminated with various radioactive isotopes due to their use in various water purification processes in the system. Radiation doses from the spent filters can vary from low to high levels. To dispose of drums containing spent filters as radioactive waste, the inventory of radioactive isotopes in the filters must be determined. Two methods for determining the inventory are indirect measurement using scaling factors and direct analysis of filter samples. This study suggests a method to determine the appropriate sample size for each drum based on the number of filters stored in the drum, when direct analysis is used to determine the inventory of radioactive isotopes. In particular, Visual Sample Plan (PNNL) software’s Item Sampling function was used to calculate the sample size, considering the confidence level and minimum acceptable coverage rate. As a result, assuming that the number of filters packed per drum ranges from a minimum of 1 to a maximum of 30, the study suggests that a full inspection is required for drums containing 9 or fewer filters, while drums containing 10 filters should be sampled with 9 samples, 11 filters with 10 samples, 12-13 filters with 11 samples, 14-16 filters with 12 samples, 19-22 filters with 14 samples, 23-26 filters with 15 samples, and 27-30 filters with 16 samples.

Recognition of Transmembrane Protein 39A as a Tumor-Specific Marker in Brain Tumor

Jisoo Park,Hyunji Lee,Quangdon Tran,Kisun Mun,Dohoon Kim,Youngeun Hong,So Hee Kwon,Derek Brazil,Jongsun Park,Seon-Hwan Kim 한국독성학회 2017 Toxicological Research Vol.33 No.1

Transmembrane protein 39A (TMEM39A) belongs to the TMEM39 family. TMEM39A gene is a susceptibility locus for multiple sclerosis. In addition, TMEM39A seems to be implicated in systemic lupus erythematosus. However, any possible involvement of TMEM39A in cancer remains largely unknown. In the present report, we provide evidence that TMEM39A may play a role in brain tumors. Western blotting using an anti-TMEM39A antibody indicated that TMEM39A was overexpressed in glioblastoma cell lines, including U87-MG and U251-MG. Deep-sequencing transcriptomic profiling of U87-MG and U251-MG cells revealed that TMEM39A transcripts were upregulated in such cells compared with those of the cerebral cortex. Confocal microscopic analysis of U251-MG cells stained with anti-TMEM39A antibody showed that TMEM39A was located in dot-like structures lying close to the nucleus. TMEM39A probably located to mitochondria or to endosomes. Immunohistochemical analysis of glioma tissue specimens indicated that TMEM39A was markedly upregulated in such samples. Bioinformatic analysis of the Rembrandt knowledge base also supported upregulation of TMEM39A mRNA levels in glioma patients. Together, the results afford strong evidence that TMEM39A is upregulated in glioma cell lines and glioma tissue specimens. Therefore, TMEM39A may serve as a novel diagnostic marker of, and a therapeutic target for, gliomas and other cancers.

Validation of ISOCS Measurements Using MicroShield

Jisoo Yoon,Kyung Rok Park,Jung-Kwon Son,Woo Yong Kim 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

In nuclear power plant environments, the analysis of gamma-emitting waste materials with complex shapes can be challenging. ISOCS (In-Situ Objective Counting System) is employed to measure the gamma-emitting radionuclide concentrations. However, it is crucial to validate the accuracy of ISOCS measurements. This study aims to validate the accuracy of ISOCS measurement results for spent filters. The ISOCS measurement process begins with modeling and efficiency calculations of the target spent filters using ISOCS software. ISOCS offers the advantage of direct measurement assessment by incorporating shielding materials and collimators into the detector efficiency calculation during the modeling process, without the need for separate efficiency correction sources. To validate the accuracy of ISOCS measurement results, the measured radioactivity values were used as input data for the MicroShield computer code to derive dose rates. These dose rates were then compared to the dose rates measured on-site, confirming the reliability of ISOCS measurements. In the field, ISOCS gamma measurements and surface dose rates were measured for three Cavity filters and four RCP Seal Injection filters. The measured dose rate for the Cavity filters was around 270 ?Svhr, and the computed values using MicroShield showed an error of approximately 12%. Despite modeling and calculation errors in computer analysis and potential uncertainties in the measurement environment and instrument, the computed values closely matched the measured values. However, the measured dose rate for the RCP Seal Injection filters ranged 2.9~8 ?Svhr, which is very low and close to background levels. When compared to the results of computer analysis, an error ranging from 27% to 97% was observed. It is concluded that validating the accuracy in the low dose rate range close to background levels is challenging through a comparison of calculated and measured dose rates.

Development of a Remote Processing System for Spent Filter Handling

Jisoo Yoon,Kyung Rok Park,Jung-Kwon Son 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

Since 1996, spent filters from the Kori unit 1 have been stored in enclosed areas such as the auxiliary building filter room. To dispose of these spent filters at a disposal facility, it is necessary to retrieve and package them according to the disposal criteria. The Kori unit 1 filter room is a 2.5- meter deep hole with 227 spent filters stored indiscriminately by type and radiation level. Furthermore, the exposure dose rate measurements revealed exceed 10 mSv/h, making it a challenging environment for workers. Therefore, in this study, we have developed a ‘Remote Processing System for Spent Filter Handling’ to minimize worker exposure and ensure safety throughout the entire process, from filter retrieval to radiation measurement, sample collection, compression, and packaging. We have completed performance testing through laboratory validation. The ‘Remote Processing System for Spent Filter Handling’ consists of four main components: a robot system for retrieving spent filters from the filter room, a transfer mechanism for moving spent filters to the lower area, a core ring device for sample collection, and finally, a compression/ packaging unit. The laboratory validation performance testing was conducted by installing these devices in a structure simulating the Gori-1 reactor filter room. The results confirmed that all processes, from spent filter retrieval to packaging, can be remotely operated without the need for filter drops or worker intervention. Through the laboratory validation, some areas for improvement were identified. These improvements should be taken into consideration when producing the system for future on-site applications.

Protrusion of hepatocellular carcinoma is a predictor of early recurrence in hepatectomy patients after spontaneous rupture

Jisoo Lee,Seung Rim Han,Kyung-Sik Kim,Seung Hyun Kim,Jong Hwan Lee,Chanwoo Cho,Nuri Lee,Gyu-Seong Choi,Jong Man Kim,Choon Hyuck David Kwon,Jae-Won Joh 한국간담췌외과학회 2016 한국간담췌외과학회 학술대회지 Vol.2016 No.4

Speech Separation through Audio-Visual Learning: A Survey

Jisoo Park,Junseok Kwon 대한전자공학회 2023 대한전자공학회 학술대회 Vol.2023 No.6

Audio-visual learning has gained significant attention in the field of deep learning, as it seeks to leverage the relationship between audio and visual modalities to improve audio-based tasks. Speech separation is a significant aspect of audio-visual learning that aims to address the cocktail party problem, where multiple sound sources overlap, making it challenging to isolate individual speech signals. In this survey paper, we provide an overview of the recent advances in audio-visual speech separation techniques and review the commonly used datasets in this area. We also identify the remaining challenges and discuss potential approaches for future research.

Development of Calibration Drum Production Method for Non-Destructive Assay System for Packaging Spent Filters

Jisoo Yoon,Kyung Rock Park,Jung-Kwon Son 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

In order to permanently dispose of radioactive waste drums generated from nuclear power plants, disposal suitability must be demonstrated and the nuclides and radioactivity contained in the waste drums, including those in the shielding drums, must be identified. At present, reliable measurements of the nuclide concentration are performed using drum nuclide analysis devices at power plants and disposal facilities during acceptance inspection. The essential functions required to perform nuclide analysis using the non-destructive assay system are the correction for self-attenuation and the dead time correction. Until now, measurements have mainly been performed for drums containing solid waste such as DAW drums using SGS calibration drums with ordinary iron drums. However, for drums containing non-uniform radioactive waste, such as waste filters embedded in cement within shielding drums, a separate calibration drum needs to be produced. In order to produce calibration drums for shielded and embedded waste drums, the design considered the placement of calibration sources, setting of shielding thickness, correction for medium density, and cement mixing ratio. Based on these considerations, three calibration drums were produced. First, a shielding drum with an empty interior was produced. Second, a density correction drum filled with cement was produced to create apparent density on the surface of the shielding drum. Third, a physical model drum was produced containing a mock waste filter and cement filled in the shielding drum.

연소합성법을 이용한 초전도성 이붕화 마그네슘분말의 제조

김지수,권혁보,전병세,윤존도,송규정 경남대학교 신소재연구소 2002 신소재연구 Vol.14 No.-

최근 이붕화 마그네슘(MgB_2)이 39K에서 초전도성을 나타내는 것이 새롭게 밝혀져 그 특성 및 활용에 있어서도 많은 연구가 이루어지고 있다. 분말 제조방법이 어렵고, 분말제조시 예열과 고압이 필요한 이붕화 마그네슘을 본 연구에서는 연소합성법을 이용하여 순수 이붕화마그네슘(MgB_2) 분말을 상온에서 성공적으로 합성하였다. 제조된 분말의 특성평가를 위해서 엑스선 회절분석기(XRD), 주사전자현미경(SEM), 자기특성측정시스템(MPMS)을 사용하여 성분분석, 결정성과 미세구조, 초전도 특성을 분석하였다. MgB_2 with a superconducting property of at 39K transition temperature has been identified recently, and it has been strongly attracted by the many scientists. Intensive studies have been performed on its properties and applications. In this study, the pure MgB_2 powders were prepared by using combustion synthesis at room temperature and atmospheric pressure. Superconductivity of produced MgB_2 were analyzed using Magnetic Properties Measurement System (MPMS) and the microstructure was observed by Scanning Electron Microscopy (SEM) and phase was identified by X-Ray Diffraction parameter (XRD).