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^161, ^163Dy의 0.003eV~50keV의 중성자 포획 단면적 측정
민영기,윤정란,노태익,김귀년,이삼열 東亞大學校附設基礎科學硏究所 2002 基礎科學硏究論文集 Vol.19 No.1
교토대학 원자로 연구소의 46MeV 전자선형가속기를 사용하여 중성자 TOF 방법으로, 에너지 영역 0.003eV∼50keV의 ^161, 163Dy sample의 중성자 포획 단면적을 측정하였다. 본 실험에서 사용된 Bi_4Ge_3O_12(BGO) 섬광 검출기는 sample의 핵반응에서 나오는 즉발 포획 감마선 측정에 사용하였다. 이 검출기는 중성자 선원으로부터 거리 12.7±0.02m 위치에 12개의 블록으로 되어 있으며, sample에 포획되는 중성자 flux의 절대치를 구하기 위해 Sm(n, γ) 및 ^10B(n, αγ) 반응을 이용하였다. ^161, 163Dy에 대한 포획 단면적 측정결과는 ENDF/B-VI 결과와 비교하였다. The neutron capture cross sections of ^161, 162Dy has been measured in the energy region from 0.003eV 50keV by using the neutron time-of-flight(TOF) promptγmethod with a 46MeV electron linear accelerator at the Research Reactor Institute, Kyoto University. An assemble of twelve pieces of BGO scintillation detectors, which was placed at a distance of 12.7±0.02mm from the neutron source, was employed as a total energy absorption detector for the prompt capture gamma-ray measurement, to obtain the absolute capture cross section value. The sample of ^161, 163Dy is a form of metallic plate. An enriched boron sample was employed to monitor the neutron flux/spectrum of the TOF beam using the standard reference cross section of the ^10B(n, αγ) reaction. Previous measurements and evaluated data in ENDF/B-VI was compared with the present results.
Kim, Gui-Ran,Ramakrishnan, Sudha Rani,Kwon, Joong-Ho Pergamon 2018 Radiation physics and chemistry Vol.152 No.-
<P><B>Abstract</B></P> <P> <I>Saengshik</I> products usually include powders of plant-derived foods that are normally non-heated and thus have inherent limitations in microbial control. Here, we investigated the microbial reduction and sensorial properties of two types of <I>Saengshik</I> products commercially available in Korean markets after electron-beam and gamma-ray irradiation (0, 1, 3, 5, and 10 kGy). The initial microbial loads in the products were 6–7 log colony-forming units (CFU)/g of total aerobic bacteria (TAB), 4–5 log CFU/g of yeasts and molds (YM), and ≤ 3 log CFU/g of coliforms. Radiosensitivities (D<SUB>10</SUB> values) of TAB, YM, and the indicator pathogens <I>Clostridium perfringens</I> and <I>Bacillus cereus</I> were 1.21–1.86 kGy, 1.03–1.97 kGy, 0.42–0.48 kGy and 0.58–0.68 kGy, respectively, regardless of the radiation source or product type. Radiation 5D values for both pathogens were 2.10–3.40 kGy, which is the dose needed to achieve the recommended 5-log reduction. The radiation sensitivity (D<SUB>10</SUB> and 5D values) was higher in <I>B. cereus</I> than in <I>C. perfringens</I> for both samples. Irradiation up to 10 kGy induced negligible changes in sensory scores for the <I>Saengshik</I> samples (p > 0.05). An electronic nose effectively distinguished the flavor profiles of irradiated products between 10 kGy and ≤ 5 kGy approved by the Korean Food Code for <I>Saengshik</I> ingredients. These results indicate that 5 kGy irradiation with electron-beam or gamma-ray was sufficient for achieving microbial control in powdered <I>Saengshik</I> products.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Radiosensitivity of microorganisms in <I>Saengshik</I> products was studied. </LI> <LI> Irradiation > 9 kGy is needed for 5-log decrease in aerobic bacteria, yeasts, and molds. </LI> <LI> D<SUB>10</SUB> values of <I>C. perfringens</I> and <I>B. cereus</I> were 0.48 and 0.68 kGy, respectively. </LI> <LI> Dose up to 10 kGy induced negligible changes in sensory attributes of <I>Saengshik</I>. </LI> </UL> </P>
Kim, Gui-Ran,Shahbaz, Hafiz Muhammad,Kyung, Hyun-Kyu,Kwon, Joong-Ho Korean Society of Food Science and Technology 2018 Food Science and Biotechnology Vol.27 No.2
This study investigated the prevalence of microbiological contamination in commercial Saengshik products (samples SP-1 to SP-12) from the Korean market, and identified their irradiation status. SP-2, SP-8, and SP-12 showed less than 3.66 and 1.10 log colony forming units (CFU)/g in total plate and coliforms counts, respectively, while the remaining samples showed more than 4.70 and 2.35 log CFU/g, respectively. Four samples were positive on some of foodborne pathogenic bacteria (Clostridium perfringens, Escherichia coli O157:H7, and Bacillus cereus). SP-2, SP-8, and SP-12 contained no pathogenic bacteria and were suspected to have been irradiated. They were confirmed as positive using photostimulated luminescence (PSL) analysis. PSL positive results on samples SP-2, SP-8 and SP-12 were finally confirmed by the authentic thermoluminescence (TL) analysis on the basis of TL glow curve shape, intensity, temperature range of TL peak maxima and TL ratio ($TL_1/TL_2$).
시판 정치배양 현미식초의 유리아미노산 및 휘발성 향기성분 특성 분석
김귀란(Gui Ran Kim),윤성란(Sung Ran Yoon),이수원(Su Won Lee),정미선(Mi Seon Jeong),곽지영(Ji Young Kwak),정용진(Yong Jin Jeong),여수환(Soo Hwan Yeo),권중호(Joong Ho Kwon) 한국식품저장유통학회 2011 한국식품저장유통학회지 Vol.18 No.5
This study was performed to evaluate the quality of the commercial brown-rice vinegars of South Korean and Japanese origins, which were prepared via static acetic-acid fermentation. The major free amino acids of Korean brown-rice vinegars were proline, glutamic acid and phenylalanine, while those of the Japanese were proline, valine, phenylalanine, lysine, γ-aminobutyric acid, alanine and isoleucine. The γ-aminobutyric acid (GABA) and total amino acids (3686.37~4212.27 mg%) contents were found to be significantly higher in the Japanese than in the Korean brown-rice vinegars. The key volatile compounds of the Korean brown-rice vinegars, analyzed with GC-MS, were acetic acid, benzaldehyde, phenethyl alcohol and phenethyl acetate while those of the Japanese brown-rice vinegars were acetic acid, ethyl acetate, ethyl alcohol, isoamyl acetate, phenethyl acetate and benzaldehyde. The volatile patterns of the Korean and Japanese commercial brown-rice vinegars were effectively distinguished from each other using an electronic nose, through which it was also elucidated that the volatiles profiles were similar among the Japanese vinegars but were different among the Korean vinegars.