• Nuclear Engineering and Technology
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• 제48권1호
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• pp.55-63
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• 2016

Calculation of the core neutronic parameters is one of the key components in all nuclear reactors. In this research, the energy spectrum and spatial distribution of the neutron flux in a uranium target have been calculated. In addition, sensitivity of the core neutronic parameters in accelerator-driven subcritical advanced liquid metal reactors, such as electron beam energy ($E_e$) and source multiplication coefficient ($k_s$), has been investigated. A Monte Carlo code (MCNPX_2.6) has been used to calculate neutronic parameters such as effective multiplication coefficient ($k_{eff}$), net neutron multiplication (M), neutron yield ($Y_{n/e}$), energy constant gain ($G_0$), energy gain (G), importance of neutron source (${\varphi}^*$), axial and radial distributions of neutron flux, and power peaking factor ($P_{max}/P_{ave}$) in two axial and radial directions of the reactor core for four fuel loading patterns. According to the results, safety margin and accelerator current ($I_e$) have been decreased in the highest case of $k_s$, but G and ${\varphi}^*$ have increased by 88.9% and 21.6%, respectively. In addition, for LP1 loading pattern, with increasing $E_e$ from 100 MeV up to 1 GeV, $Y_{n/e}$ and G improved by 91.09% and 10.21%, and $I_e$ and $P_{acc}$ decreased by 91.05% and 10.57%, respectively. The results indicate that placement of the Np-Pu assemblies on the periphery allows for a consistent $k_{eff}$ because the Np-Pu assemblies experience less burn-up.

• JSTS:Journal of Semiconductor Technology and Science
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• 제5권1호
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• pp.58-66
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• 2005

Inertial-grade vertical-type and lateral-type differential resonant accelerometers (DRXLs) are designed, fabricated using one process and tested for navigational applications. The accelerometers consist of an out-of-plane (for z-axis) accelerometer and in-plane (for x, y-axes) accelerometers. The sensing principle of the accelerometer is based on gap-sensitive electrostatic stiffness changing effect. It says that the natural frequency of the accelerometer can be changed according to an electrostatic force on the proof mass of the accelerometer. The out-of-plane resonant accelerometer shows bias stability of $2.5{\mu}g$, sensitivity of 70 Hz/g and bandwidth of 100 Hz at resonant frequency of 12 kHz. The in-plane resonant accelerometer shows bias stability of $5.2{\mu}g$, sensitivity of 128 Hz/g and bandwidth of 110 Hz at resonant frequency of 23.4 kHz. The measured performances of two accelerometers are suitable for an application of inertial navigation.

• 한국지반공학회논문집
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• 제17권1호
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• pp.57-65
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• 2001

역사적 지진 발생 기록이 풍부하고 양산 단층 영향권 내에 있어 지진 발생 가능성이 높은 경주 지역을 대상으로 지진민감도 분석을 수행하였다. 지형적 특성을 고려한 지반조사와 현장 및 실내 시험을 통하여 대상 지역 지반의 지층 구성과 각 지층의 동적 특성을 분석 평가하고, 이를 토대로 한 지반 응답 해석을 수행하였다. 9개의 시험공을 시추하여 2개소의 크로스홀 시험과 7개소의 다운홀 시험을 실시하였고, 시추부지 포함 13개소에서 SASW 시험도 수행하였다. X선 회절 및 풍화도 분석과 공진주 시험 등의 실내시험도 병행하였다. 이러한 시험 결과를 바탕으로 El Centro 지진에 의한 지표면 최대 가속도를 등가 선형 부지응답해석을 통해 평가한 결과 붕괴방지 수준에서 0.158g~0.286g, 기능수행 수준에서 0.067g~0.116g의 분포를 보였고 퇴적층에 의하여 형성된 경주 시가지 분지 지형에서 증폭정도가 심하다는 것을 알 수 있었다. 해석 결과로 볼 때, 현행 건교부 기준 설계응답스펙트럼은 경우에 따라 지반 운동을 과소평가하고 지반 고유의 공진 현상을 고려하지 못하였다. 이러한 문제를 해결하기 위하여 개선된 지반 분류방법을 소개하였고 부지고유의 지반응답평가의 중요성에 대해 제시하였다.

• 한국연초학회지
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• 제32권1호
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• pp.19-27
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• 2010

The aim of this study is to compare the sensitivity of both two NCI-H292 and A549 cell types to acute inflammatory responses induced by cigarette smoke. For this, we treated two kinds of smoke fractions derived from 2R4F reference cigarettes: total particulate matter(TPM) collected onto a Cambridge filter pad and gas/vapor phase(GVP) prepared by bubbling through in buffer solution. When we measured cellular cytotoxicity by neutral red uptake assay after treatment for 24 hours, TPM and GVP induced cytotoxic effect in a dose-dependent manner in the range of 10-$100{\mu}g$/mL and 60-$300 {\mu}g$/mL., respectively, in both cell types without any cellular difference. Additionally, when we examined acute inflammatory responses by analyzing cytokines secreted into culture media including tumor necrosis factor-$\alpha$ (TNF-$\alpha$), interleukin-8(IL-8), and transforming growth factor-$\alpha$(TGF-$\alpha$) as well as matrix metalloproteinase-1(MMP-1), the treatment with smoke fractions increased those marker proteins in a dose-dependent manner in NCI-H292. Meanwhile, in A549 cells only MMP-1 was observed to be increased in a dose-dependent fashion. Collectively, our data indicate that NCI-H292 cell type is more sensitive to cigarette smoke-induced inflammatory response than A549 cells. This suggests that NCI-H292 could be useful as an in vitro evaluation tool to assess harmful effects of cigarette smoke.

• 한국환경보건학회지
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• 제30권4호
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• pp.347-351
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• 2004

A battery of sediment bioassays was performed for the sediments from the intertidal flat zone along the middle west coast of Korea to assess their potential toxicity. In the bioassays, three crustaceans, Daphnia magna, Nitocra spines, and Hyalella aztec a were exposed to $16\%$ sediments (wet weight) collected from 14 sites. Immobility($\%$) was checked as an endpoint after 24- and 48-h exposure of Daphnia magna and after 96-h exposure of Hyalella azteca and Nitocra spines. Among the three bioassays, the 48-h Daphnia bioassay showed the most distinct differential sensitivity in relation to sediment contamination, while the Nitocra and the Hyalella bioassays failed to show the differential sensitivity properly among the sites classified as polluted. Significantly different levels of immobility ($\%$) were obtained between the sites classified as chemical/nutrient polluted and the sites classified as non-polluted in the Daphnia bioassays, but not in the Nitocra bioassay and the Hyalella bioassay. Some differences of toxic response to the same sediments among bioassays were observed, suggesting that there may be a chemical specificity of response sensitivity to sediment toxicity, due to differences in bio-availability of sediment toxicants among test species.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.52-57
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• 2004

해체부지 선량평가 모델의 주요 핵종에 대한 key parameter를 분석하기 위하여 민감도 분석을 수행하였다. 본 연구에서 민감도 분석을 수행하기 위한 주요 가정 사항으로서 피폭시나리오는 가장 보수적인 resident farmer를 그리고 방사성핵종의 오염 정도는 0.037 Bq/g로 하였다. 분석결과, 감마 방출 핵종인 Cs-137과 Co-60의 경우에는 오염지역의 면적과 거주관련 변수(외부감마차폐인자와 실내 거주시간분율), C-14 핵종의 경우에는 환경변수와 불포화층의 수문학적 변수가, Sr-90 핵종의 경우에는 오염지역의 토양 밀도가 선량에 미치는 영향이 큰 parameter로 확인되었다.

• The Plant Pathology Journal
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• 제16권4호
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• pp.222-226
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• 2000

In disease surveys from 1986 ti 1998, disease incidence of tobacco black shank was gradually increased in burley tobacco from 1996. To study the causes of the disease occurrence, one hundred and fourteen isolates of Phytophthora parasitica var. nicotianae (Ppn) were collected from burley tobacco-growing areas in the southern part of Korea during 1996-1997, and tested in vitro for meatlaxyl sensitivity which was determined by measuring the mycelial growth on corn meal agar (CMA) amended with metalaxyl. Of the tested isolates, 78.1% showed sensitive to metalaxyl, having $\textrm{ED}_{50}$ values less than 1.0 $\mu\textrm{g}/$\textrm{ml}, while 1.7% was resistant weth $\textrm{ED}_{50}$ greater than 100 $\mu\textrm{g}/$\textrm{ml}. Ppn isolates from three provinces, Chungnam, Chonbuk and Chonnam showed similar distributions of metalaxyl sensitivity. Metalaxyl-resistant isolates were not significantly different from metalaxyl-sensitive ones in mycelial growth rate, chlamydospore formation capacity and size of the spore, and pathogenicity on tobacco plant (cv. Burley 21). These results suggest that the metalaxyl-resistant Ppn in burley tobacco may be one of the major factors to cause the higher occurrence of the tobacco black shank in the burley tobacco-growing area.

• Archives of Pharmacal Research
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• 제29권2호
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• pp.152-158
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• 2006

To examine a possible synergistic role for p73 and cisplatin (cis-diamminedichloroplatinum II) in HeLa cells with a nonfunctional p53 protein, we established stable HeLa/p73 clones using a tetracycline inducible eukaryotic expression vector. The HeLa/p73 clones were not characterized by changes in growth or morphology. Cell death analysis, however, indicated a greater sensitivity to cisplatin in the p73-overexpressed HeLa cells than determined for the noninduced HeLa cells. This increased sensitivity seems to affect an induction of a sub-G1 population as assessed from flow cytometry analysis. The increased sub-G1 population may, in turn, result from a reduction of cyclin D1 and B1 expression by cisplatin in the presence of p73. Hoechest staining indicated an increased number of dead cells in the p73-induced cells compared to the non-induced cells. Poly ADP-ribose polymerase (PARP) cleavage was shown to be distinct in the p73-overexpressed cells compared to non-induced cells, which suggests that p73 modulates the cisplatin-induced apoptosis. Therefore, a synergistic effect of p73 and cisplatin to induce apoptosis could lead to new treatment for some types of human cancers.

• Journal of Nutrition and Health
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• 제22권4호
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• pp.266-274
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• 1989

The current study was undertaken to determine the effects of the ratios of dietary fat to carbohydrate and energy restriction on insulin sensitivity in the growing rats. Male rats weighting 80-90g were fed experimental diets for two weeks. Rats were killed and epiddymal adipose tissue were removed and sliced. Explants of adipose tissues were incubated for 2 hours in KRB(Krebs-Ringer bicarbonate) buffer containing various concentrations of human insulin and [U-14C]glucose. Insulin sensitivity was determined as glucose conversion to total lipids (lipogenesis) during 2 hr incubation. Exp't I : Effects of Ratios of Fat to Carbohydrate on Insulin Sensitivity. Eighteen male rats were fed 3 diets for 2 weeks. Diet 1 was low fat-high carbohydrate (4% soybean oil and 66.5% cornstarch) ; diet 2, medium fat-medium sarbohydrate(12% soybean oil and 58.5% cornstarch) ; diet 3, high fat-low carbohydrate (20% soybean oil and 50.5% cornstarch). Insulin sensitivity was higher in the order of LF-HC, MF-HC and HF-LC diet groups (p<0.05), i.e, lipogenesis was higher at all insuline concentration in the explants from rats fed LF-HC diet. However, thers was no significant difference in body weight gain and epididymal adipose tissue weight among treatments. Exp't II ; Effects of Energy Restriction on Insulin Sensitivity. Twelve rats were grouped into ad libitum feeding and restricted feeding(70% of ad libitum). The experimental diet was medium fat-medium carbohydrat diet as used in the Exp't I. Restricted feeding group tended to show higher insulin sensitivity compared to ad libitum group. However, there was no statistical difference between two groups. As expected, body weight gain and epididymal adipose tissue were higher in the ad libitum group. In summary, the resutls of the current study showed that the epididymal adipose tissue taken from the rats fed low fat-high carbohydrate diet showed higher insulin sensitivity compared to those fed high fat-low carbohydrate, and that resticted feeding tended to elevate insulin sensitivity in these tissues.

• 대한통합의학회지
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• 제10권2호
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• pp.125-134
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• 2022

Purpose : Establishing multicultural acceptance is important to provide quality nursing care in various clinical settings and adapt to changing roles in different situations. The purpose of this study was to explore degree of intercultural sensitivity, cultural empathy, and multicultural acceptance, the factors influencing of multicultural acceptance of nursing students and to provide the basic data to increased multicultural acceptance. Methods : The study used a questionnaires that include general characteristics, multicultural acceptance, intercultural sensitivity, cultural empathy for nursing students. This research involved 173 nursing students in G city. The data collected from August 15, 2021 to August 30, 2021. The study was analyzed using the SPSS 23.0 program. The correlation among intercultural sensitivity, cultural empathy, and multicultural acceptance was analyzed by Pearson's correlation coefficients, and it was analyzed using multiple regression to figure out factors influencing multicultural acceptance. Results : The multicultural acceptance score was above the middle level and differed according to the academic grade (F=8.580, p<.001), major satisfaction (F=5.981, p=.003), interpersonal relations significantly (F=6.837, p=.001). Multicultural acceptance was a significant positive correlation with intercultural sensitivity (r=.544, p<.001), cultural empathy (r=.624, p<.001). As a result of regression analysis, it was confirmed that cultural empathy (β=.477, p<.001) and intercultural sensitivity (β=.212, p<.001) were factors that influence nursing students' multicultural acceptance ; this model could explain 40 %. Conclusion : Factors affecting multicultural acceptance of nursing students are cultural empathy and intercultural sensitivity. Nursing students are encouraged to have multicultural acceptance in terms of satisfaction of cultural empathy and intercultural sensitivity. Through this research requires the fellow study to determine the various factors affecting multicultural acceptance of nursing students. And it is necessary to development education and program that can enhance multicultural acceptance is required.