Uranium Enrichment Determination Using a New Analysis Code for the U XKα Region: HyperGam-U

김준혁,최희동,박종호 한국원자력학회 2016 Nuclear Engineering and Technology Vol.48 No.3

HyperGam-U was recently developed to determine uranium enrichment based on g- and Xrayspectroscopy analysis. The XKa region of the uranium spectrum contains 13 peaks for235U and 238U and is used mainly for analysis. To describe the X-ray peaks, a Lorentzianbroadened shape function was used, and methods were developed to reduce the number offitting parameters for decomposing the strongly overlapping peaks using channel-energy,energy-width, and energy-efficiency calibration functions. For validation, eight certifiedreference material uranium samples covering uranium enrichments from 1% to 99% weremeasured using a high-resolution planar high-purity germanium detector and analyzedusing the HyperGam-U code. When corrections for the attenuation and true coincidencesumming were performed for the detection geometry in this experiment, the goodness offit was improved by a few percent. The enrichment bias in this study did not exceed 2%compared with the certified values for all measured samples.

Correction of pixie ear: infraauricular skin redraping method

김준혁,양영빈,Deuk Young Oh 대한두개안면성형외과학회 2022 Archives of Craniofacial Surgery Vol.23 No.4

Patients with pixie ear have an attached, tapering, and low-set earlobe. Traditional methods usually describe excision of the caudal portion of the lobule and reattachment in a more superior position. The present report suggests a simplified skin redraping method for correction of pixie ear. The procedure provides easy method to design and perform, which only requires elevation and trimming of the skin. Other ancillary procedures, such as flap design, anchoring, plication, and subdermal fixation, are not required. This method produces satisfactory results. Postoperative scar is invisible because the incision is on the retroauricular region, and the corrected earlobe has a more natural appearance than the repositioned earlobe. Moreover, skin redraping avoids tension, which contributes to minimization of the postoperative scar.

미생물 연료 전지에서 전극 구조에 따른 전기화학적 영향

김준혁,채형원,Tran Viet Hoa Huong,정석희 대한환경공학회 2018 대한환경공학회 학술발표논문집 Vol.2018 No.11

주요국 슈퍼컴퓨터 동향 분석

김준혁 한국기술혁신학회 2016 한국기술혁신학회 학술대회 발표논문집 Vol.2016 No.10

한국전력 배전용 변압기 자산관리를 위한 수분함유량 영향분석

김준혁 한국조명·전기설비학회 2023 조명.전기설비 Vol.37 No.3

Formation of Stereocomplex Structure and Surface-modified Magnesium Hydroxide for Higher Mechanical Properties and Anti-inflammatory Effects of PLLA Composites

김준혁,백승운,한동근 한국고분자학회 2023 한국고분자학회 학술대회 연구논문 초록집 Vol.48 No.2

사고 대응 작업자 피폭선량 평가

김준혁,윤선홍,배진형,차길용 (사)한국방사선산업학회 2023 방사선산업학회지 Vol.17 No.3

To effectively and safely manage the radiation exposure to nuclear power plant (NPP)workers in accidents, major overseas NPP operators such as the United States, Germany, and Francehave developed and applied realistic 3D model radiation dose assessment software for workers. Continuous research and development have recently been conducted, such as performing NPP accidentmanagement using 3D-VR based on As Low As Reasonably Achievable (ALARA) planning tool. In linewith this global trend, it is also required to secure technology to manage radiation exposure of workersin Korea efficiently. Therefore, in this paper, it is described the application method and assessmentresults of radiation exposure scenarios for workers in response to accidents assessment technology,which is one of the fundamental technologies for constructing a realistic platform to be utilized forradiation exposure prediction, diagnosis, management, and training simulations following accidents. First, the post-accident sampling after the Loss of Coolant Accident (LOCA) was selected as the accidentand response scenario, and the assessment area related to this work was established. Subsequently,the structures within the assessment area were modeled using MCNP, and the radiation source of theequipment was inputted. Based on this, the radiation dose distribution in the assessment area wasassessed. Afterward, considering the three principles of external radiation protection (time, distance,and shielding) detailed work scenarios were developed by varying the number of workers, the presenceor absence of a shield, and the location of the shield. The radiation exposure doses received by workerswere compared and analyzed for each scenario, and based on the results, the optimal accident responsescenario was derived. The results of this study plan to be utilized as a fundamental technology to ensurethe safety of workers through simulations targeting various reactor types and accident responsescenarios in the future. Furthermore, it is expected to secure the possibility of developing a data-basedALARA decision support system for predicting radiation exposure dose at NPP sites.

14종 국화과(Asteraceae) 식물 종자 추출물의 항산화 활성

김준혁,이다현,이미현,정영호,박초희,이희호,나채선,Kim, JunHyeok,Lee, Da Hyun,Lee, Mi Hyun,Jung, Young Ho,Park, Cho Hee,Lee, Hee Ho,Na, Chae Sun 한국생명과학회 2021 생명과학회지 Vol.31 No.6

국화과 식물은 현화식물 중 약 10%를 차지하며, 한반도에서 전통적으로 약용 식물로 사용되었다. 본 연구는 14종 국화과 식물 종자 추출물의 항산화 활성 평가를 통해 식물의 다양성 보전에 기여하기 위해 진행되었다. 충실률 90% 이상이고 발아율이 50% 이상인 종자를 대상으로 실험을 진행하였다. 총 페놀성 물질의 함량은 포천구절초(13.5 mg GAEs/g seeds), 구절초(11.8 mg GAEs/g seeds), 과꽃(11.0 mg GAEs/g seeds) 순으로 가장 높게 나타났다. 총 플라보노이드 함량은 과꽃(9.8 mg QEs/g seeds), 포천구절초(7.2 mg QEs/g seeds), 서양민들레(6.3 mg QEs/g seeds) 순으로 가장 높게 나타났다. DPPH 라디컬 소거활성은 종자 추출물의 종자 추출물의 IC₅₀ 값을 기준으로 포천구절초(57.4 ㎍/ml), 서양민들레(59.1 ㎍/ml), 구절초(65.0 ㎍/ml) 순으로 가장 높게 나타났다. ABTS 라디컬 소거활성은 종자 추출물의 IC₅₀ 값을 기준으로 과꽃(26.2 ㎍/ml), 포천구절초(38.4 ㎍/ml), 서양민들레(40.2 ㎍/ml) 순으로 가장 높게 나타났다. 항산화 활성을 기반으로 한 군집분석에 따라 14 종은 항산화 활성이 높은 group 4에서 항산화 활성이 낮은 group 0까지 5개의 group으로 분류되었다. 높은 페놀성 함량과 항산화 활성을 갖는 group 3와 4에 속하는 구절초, 포천구절초, 서양민들레, 과꽃 종자는 식물 유래 천연 항산화제로써 유력하다. Approximately 10% of all angiosperms belong to the Asteraceae family. Plant species belonging to this family have traditionally been used as medicinal plants in the Korean Peninsula. We investigated the antioxidant activity of seed extracts from 14 species belonging to the Asteraceae family. Seeds with ≥ 90% percentage of filled seed and ≥ 50% final germination were used. The total phenolic content was the highest in Dendranthema zawadskii var. tenuisectum (13.5 mg of gallic acid equivalents (GAEs)/g seeds), followed by Dendranthema zawadskii var. latilobum (11.8 mg of GAEs/g seeds), and Callistephus chinensis (11.0 mg of GAEs/g seeds). The total flavonoid content was highest in C. chinensis (9.8 mg of quercetin equivalents (QEs)/g seeds), followed by D. zawadskii var. tenuisectum (7.2 mg of QEs/g seeds) and Taraxacum officinale (6.3 mg of QEs/g seeds). Our results showed that 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity was highest in D. zawadskii var. tenuisectum (57.4 ㎍/ml), followed by T. officinale (59.1 ㎍/ml) and D. zawadskii var. latilobum (65.0 ㎍/ml), with a half maximal inhibitory concentration (IC₅₀) of DPPH scavenging activity. Furthermore, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity was highest in C. chinensis (26.2 ㎍/ml), followed by D. zawadskii var. tenuisectum (38.4 ㎍/ml), T. officinale (40.2 ㎍/ml), with a half maximal inhibitory concentration (IC₅₀) of ABTS scavenging activity. Based on a cluster analysis according to the antioxidant activity, the 14 species were classified into five groups, with group 4 having the highest antioxidant activity and group 0 having the lowest antioxidant activity. D. zawadskii var. latilobum, D. zawadskii var. tenuisectum, T. officinale, and C. chinensis belonging to groups 3 and 4, exhibited high phenolic content and antioxidant activity and can be considered potent plant-derived natural antioxidants.

실데이터 기반의 전기자동차 충전 데이터 분석 및 충전 패턴 도출

김준혁,문상근,이병성,서인진,김철환 대한전기학회 2018 전기학회논문지 Vol.66 No.11

As the interests in eco-friendly energy has increased, the interests in Electric Vehicles(EVs) are increasing as well. Moreover, due to the government's economic support for EVs, penetration level of it has rapidly increased. These sharp increases, however, induce various problems in distribution system, such as voltage/frequency variations, peak demand increasement, demand control, etc. To minimize these possible matters, lots of research have conducted. Nevertheless, most of it assumed extremely important factors, such as numbers and charging patterns of EVs. It inevitably results in errors in their research, and thus make it difficult to prevent the possible matters from EVs. In this paper, therefore, we use actual EVs charging data from KEPCO, and analysis and deduction of it were conducted. The simulations were carried out for four aspect(season, region, purpose).

경중량 수직형 충격 시험 장비의 선형 동역학 모델 수립을 통한 충격 시험 설계 기법에 관한 연구

김준혁,오부진,임담혁,Kim, Junhyeok,Oh, Boo-Jin,Im, Damhyeok 한국군사과학기술학회 2021 한국군사과학기술학회지 Vol.24 No.1

Naval surface ships and submarines could be exposed to non-contact underwater explosion(UNDEX) environment. Equipment installed on the ships and submarines could be damaged by shock load generated by UNDEX environment. Therefore, shock survivability of equipment generally evaluated by shock tests. Ground based shock test machine such as Light weight shock test machine(LVSM) is developed to simulate shock load caused by UNDEX environment. In this study, linear dynamic model of LVSM is proposed and evaluated to improve shock test design procedure. Parameters of the model are decided by optimizing time domain response compared to zero payload experiment. Proposed model is verified by comparing simulation results and test results of maximum payload experiment. Finally, shock test design using the model is described for various test equipment weight.