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A Study on the Effect of Frequency Scaling Factor on FBP
Jisu Kim,Jihun Moon,Heejun Chung,Kyung Taek Lim,Sung Woo Kwak 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2
For safeguarding dry storage facilities, a tomography system based on fast and thermal neutron detection was studied in Korea Institute of Nuclear Nonproliferation and Control. The study was conducted laboratory-scale experiments based on a custom built 1/10th scale model cask, He-4 gas scintillation detector array, and multiple 252Cf sources. A filtered back projection (FBP) was utilized to obtain the cask image via MATLAB. The Ram-Lak filter (ramp filter) was employed in FBP for improved the reconstructed image quality. The Ram-Lak filter is the increasing amplitude filter due to the increasing spatial frequency of the image. In spatial frequency, the frequency of brightness change in the low-frequency region is relatively low, and the frequency of brightness change in the highfrequency region is large. Thus, the high-frequency region in the neutron tomographic image is near the neutron sources and the cask, and the low-frequency region is outside of the cask and/or between the source and cask in the study. In order to apply the ramp filter, a Fourier transform is initially performed on projection data, and image reconstruction is performed with the corrected projection data. In this case, the filter is linearly changed. Therefore, a small filter value is applied at lower spatial frequencies to reduce the projection data, and a large filter value is applied at high spatial frequencies to reduce the projection data. The filter scale is a fraction of frequency amplitude, and the filter value applied to the projection data is determined according to the filter scale. This study was conducted for discussion of the image quality due to the effect of the filter scale used for image reconstruction of a neutron tomography system. The results show that in the experiment with one source, the source location was founded when we used the frequency scale of 0.5 and over. In the double or triple source experiment, the source locations and relative activities were found when we used a filter scale of 0.4 to 0.6. When the filter frequency scale of 0.7 to over, the relative activities are hard to know. It can be found that if the filter value is too large or too small, distortion may occur in the reconstruction results. Therefore, it seems reasonable to set a value between 0.4 and 0.6 as the scaling factor for the neutron tomography system. In the future, additional comparative studies will perform validation of the frequency scaling methods.
Jisu Song,Seung Eun Lee,Woo-Jin Yang,Han-Jo Yang,Mi-Ryung Kim 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10
Onion (Allium Cepa L) has been used as a medicinal plant in folk medicine as well as food. Onions contain a variety of bioactive compounds including quercetin. In this study, the lactic acid bacteria fermentation process was established for the development of functional materials using red onion. First, a mixture of red onion concentrate containing high amount quercetin and pumpkin was prepared and inoculated with 8 types of lactic acid bacteria. The number of viable cells, pH, acidity, and reducing sugar change were monitored for each fermentation period. In addition, polyphenol content, quercetin content, and antioxidant activity were evaluated. Lactobacillus parabuchneri (LPB) showed the highest fermentation ability and physiological activity during 5-day fermentation. The anticancer activity and the anti-inflammatory activity of LPB fermented product were confirmed by using SW480 cell and RAW264.7 cells. From the results of this experiment, the optimum conditions for lactic acid bacteria fermentation of the red onion containing high amount quercetin were set up and the possibility of functional materials using high quercetin red onion was suggested.
( Jisu Kim ),( Hye-eun Kim ),( Kyung-suk Lee ),( Sung-hoon Chung ),( Yong-sung Choi ),( Chong-woo Bae ) 대한주산의학회 2019 Perinatology Vol.30 No.1
Objective: We aimed to compare the total number of live births and survival rates of very low birth weight infants (VLBWIs) from the Statistics Korea and the Korean Neonatal Network (KNN) data between 2013 and 2016, and to find out the direction in which the total number of VLBWIs is included in KNN. Methods: We obtained the number of live births and deaths of VLBWIs and extremely low birth weight infants among vital statistics of the Statistics Korea from 2013 to 2016 and compared the differences with KNN data using the KNN annual reports during the same period. Results: The survival rates were 84.2%, 86.5%, 84.9% for VLBWIs in the Statistics Korea, and 83.4%, 86.4%, 84.6% in the KNN data from 2014 to 2016. There was no significant difference between the data. The rates of registration of VLBWIs (registration number of the KNN/registration number of the Statistics Korea) showed 50.8%, 87.7%, 87.7%, 88.3% between 2013 and 2016, respectively. It showed an increasing trend every year. However, registration rates according to the birth weight (BW) and gestational age (GA) were significantly lower in BW of less than 400 g and GA of less than 22 weeks. Conclusion: KNN is considered to be a good database representing the number of births of VLBWIs born in Korea. However, it is necessary to establish the GA of survival limits in the data of the Statistics Korea, and acquire data on the number of VLBWIs who are not collected by hospitals and clinics in Korea.
Jisu Kim,Jihun Moon,Sung-Woo Kwak 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1
Dry storage cask facilities are considered for temporary storage of spent nuclear fuels before their final disposal. According to relevant domestic laws and regulations, the integrity and gross defects of the PWR spent fuel must be inspected before they are transferred to the dry cask from a wet storage pool of a nuclear power plant. To meet nuclear safeguards requirements for a spent fuel transportation, the KINAC has been working to develop a simple and convenient Non-destructive Testing (NDT) equipment to verify the integrity and gross defects of the spent fuel assembly. This study was conducted in two processes. The first stage is to review the current NDT techniques conducted in the nuclear fuel manufacturing process. During the manufacturing process, the Ultrasonic testing (UT) and Eddy Current Testing (ECT) technique are used for detecting the cracks or foreign materials in a cladding of a fresh fuel. During an over-haul period after an end of one fuel cycle, the sipping test of the spent fuel is performed for detecting the failed fuel assemblies. If it is determined through the sipping test whether any fuel assembly contains a failed fuel rod, the failed fuel rod of lots of fuel rods in the assembly is found out using the UT instrument. The ECT is used for detecting the internal defects and oxide layer thickness of a fuel cladding. Because the UT and ECT are the wellknown technique and has already been employing for the spent fuel inspection, we adopted the UT and ECT technique for development of a new instrument for nuclear safeguards verification. The second stage is to design the UT and ECT equipment in consideration of nuclear safeguards activities in the spent fuel pool. For nuclear safeguards inspection, irradiated fuel or non-fuel items are distinguished. Thus, verification equipment newly designed using the UT and ECT should detect not only a failed rod, but also a false tube, or a false rod, or a different material from a cladding. New probe and signal processing methods are developed to achieve these goals. The design of UT and ECT probes are preferentially carried out according to technical requirements – the probe thickness including a damper material should be less than 1.0 mm - and the study on analyzing signal distortion caused from material difference will be conducted for development of the safeguards inspection equipment. Detailed results of our study will be discussed in this conference.
Physiological activity of elephant garlic fermented using lactic acid bacteria
Jisu Song,Seung Eun Lee,Woo-Jin Yang,Han-Jo Yang,Mi-Ryung Kim 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10
Elephant garlic (Allium ampeloprasum var. ampeloprasum), also called giant garlic, is a perennial plant belonging to the genus Allium and has been used as a spice or medicinal plant for centuries. In this study, we tried to establish a lactic acid fermentation process for the development of functional materials using elephant garlic. In order to set the optimal conditions for lactic acid fermentation using the elephant garlic powder, a mixture of elephant garlic and pumpkin powder was prepared and inoculated with 8 kinds of lactic acid bacteria. The number of viable cells, pH, acidity, and reducing sugar changes were monitored and polyphenol contents and antioxidant activities of them were evaluated during the fermentation period. Lactobacillus satsumensis (LS) showed excellent fermentation ability, which had high physiological activity in 48 hours of fermentation. The anti-inflammatory activity of LS fermented product was evaluated using the inhibition degree (%) of LPS-induced NO production in RAW264.7 cells and the anticancer activity was confirmed by the determination of SW480 cell growth at each sample concentration.