검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 11

        1.
        2023.05 구독 인증기관·개인회원 무료
        Since the time to consider when evaluating leakage of spent fuel dry storage systems is very long, assumptions that continue to leak at the initial leakage rate are too conservative. Therefore, this study developed a dynamic methodology to calculate the change in leakage rate using time-varying variables and apply it to calculate the amount of radioactive leakage during the evaluation period. The developed dynamic methodology was then applied to calculate the leakage radiation source term for a hypothetical dry storage system and used to perform a public dose assessment. When applying the developed dynamic leakage rate evaluation methodology for more accurate confinement evaluation in case of containment damage of dry storage system, it was found that the change of leak rate with time is very insignificant if the hole diameter is small enough, and the leak rate decreases rapidly with time when a hole with a certain diameter or larger occurs. In the case of the accident condition, except when the hole is very large, it corresponds to the chocked flow condition, and the leak rate decreases rapidly as soon as the internal pressure is sufficiently lowered to enter the molecular and continuum flow region. In the case of a small hole diameter, the leakage volume is very small, so even if the dynamic methodology is applied, the evaluation results are not different from the case where the initial leakage rate continues, and when the hole diameter exceeds a certain value, the internal pressure drops according to the leakage volume, and the leakage rate decreases significantly. As a result of evaluating the dose to residents by applying the calculated radiation source term, it was confirmed that the dose criteria was exceeded when a hole with a diameter of about 4 μm occurred under off-normal conditions, and the dose standard was exceeded under accident conditions when a chocked flow occurred between the diameter of the hole and 2-3 μm, resulting in a rapid increase in the dose. The results of this study are expected to contribute to a more accurate evaluation of the confinement performance of storage systems, which will contribute to the design of optimal dry storage systems.
        2.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 DWI 적용 시 X축 거리에 따른 신호 손실과 인공물 발생 여부를 SS-EPI 기법과 비교 분석하여, MS-EPI 기법의 특성을 제시하고 임상 적용 관련 기초자료를 제시하고자 하였다. 3.0T 자기공명영상장치와 팬텀을 사용 하여 자기장 중심축과 좌우 끝 지점 ±3cm, 3번씩 움직여 표준 영상인 T2 강조영상과 SS-EPI DWI, MS-EPI DWI(RESOLVE) 축상면 영상을 획득하였다. 각 동일 부위에서의 SS-EPI DWI, MS-EPI DWI 영상을 T2 강조영상과 감산하여 신호 손실 직경을 측정하여 정량적 분석을 하였다. 정성적 평가는 나이퀴스트 허상과 기하학적 왜곡과 신호 손실, 인공물 발생 여부를 방사선사 3명이 비교평가 하였다. 두 기법 모두 오프 센터(off-center)로 이동할수록 신호 손실구간 또는 기하학적 왜곡이 나타나는데, 특히 MS-EPI 기법에서는 좌우 신호 손실 현상이 매우 증가해 –25, +25 cm 구간에서 는 약 50% 길이가 감소하였다. MS-EPI 기법은 근골격계 질환에서 기존에 매우 높은 영상 유용성을 인정받고 있다. 그러 나 k-공간을 분할 하여 채우는 MS-EPI 기법은 오프 센터의 낮은 공간 주파수 획득 시 위상변동 보정이 안 되어 신호 손실구간이 나타나며, 이에 관한 연구는 전혀 없는 실정이다. 이에 따라 본 연구는 기존의 선행 연구에서의 보여주지 못한 임상적 적용 시 MS-EPI 기법의 문제점을 파악하면서 이러한 정보를 공유하고 추가적인 연구에 토대가 될 수 있는 기초를 마련했다는 점에 의의가 있다.
        4,000원
        3.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To investigate the effects of antioxidant activities and hair loss prevention of extracts from Platycodon grandiflorum, we’ve prepared chloroform (CF) and ethylacetate fractions (EA) extracted from P. grandiflorum. In the results of DPPH radical scavenging assay, the two fractions showed dose-dependent antioxidant activities. Furthermore, in the ABTS assay, the two fractions exhibited the inhibitory effect over 90% at 10, 50, 100, 200 mg/mL. To investigate the inflammation inhibitory effect, we used RAW264.7 cells, these extracts were inhibited inflammatory reaction by suppressing the production of nitric oxide (NO) and prostaglandin E2 (PGE2) in dose-dependent manner. In the assay of HaCaT cells’ proliferation, the 24 hr treatment of the extracts significantly accelerarted cell proliferation in the range of concentrations used. The two fractions inhibited the proliferation of Malssezia furfur, the bacteria induce the dandruff. Finally, the CF could significantly inhibit the DHT production at 1, 10, 50, 100 μg/mL, but EA showed the inhibitory effect at the concentration over 50 μg/mL. The overall results of this study suggest that the chloroform (CF) and ethylacetate fractions (EA) from P. grandiflorum could be a useful raw material for the hair loss prevention products.
        4,000원
        4.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Among service industries of knowledge based economic era, the roles of educational service field are becoming more important and standard of educational service makes a direct effect on economic development and social growth. Therefore, accurate measurement of service quality is the most important assignment and the measurement of the service quality remains difficult assignment. So, this researcher classified quality attributes applying weighted value and found potential satisfaction level(PSL) and potential customer demand improvement index(PCDI) for trainees participating in national manpower business so as to suggest measurement of service quality and easiness of use and then, calculated satisfaction position and opportunity cost by quality factor with Taguchi’s loss fraction. And, improvable satisfaction level was measured, opportunity cost by degree of customer dissatisfaction was quantitatively measured, and a model that can indicate with economic factors was suggested. In addition, methodology of measuring quality cost that can be reduced by quality improvement and direction of strategic decision-making for deciding items to be improved preferentially were suggested with qualitative index that can indicate the degree of customers’ dissatisfaction by loss.
        5,200원
        6.
        2014.03 구독 인증기관 무료, 개인회원 유료
        Panax ginseng, also known as Korean ginseng, has long been used as a broad tonic in Oriental medicine to augment vitality, health, and longevity, particularly in older people. This study investigated the effects of Korean red ginseng (RG) on bone loss in ovariectomized (OVX) mice. C3H/HeN mice (10-weeks-old) were divided into sham and OVX groups. OVX mice were treated with vehicle, 17β-estradiol (E2), RG (oral administration, 250 mg/kg/day), or RG (intraperitoneal administration, 50 mg/kg/every other day) for 6 weeks. Serum E2 concentration and alkaline phosphatase (ALP) activity were measured. Tibiae were analyzed using microcomputed tomography. Biomechanical properties and osteoclast surface level were measured. There was no significant difference in the degree of grip strength, body weight, uterine weight, mechanical property, tibiae length, or tibiae weight between the OVX and RG-treated groups. Compared with the OVX group, the serum ALP level was significantly lower in the RG-treated groups. Serum E2 levels and osteoclast surface levels did not change between the OVX and RG-treated groups. RG could not preserve trabecular bone volume, trabecular bone number, trabecular separation, trabecular thickness, structure model index, or bone mineral density of the proximal tibiae metaphysic. In conclusion, there was no definite effect of RG on OVX-induced bone loss in C3H/HeN mice.
        4,000원
        7.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We investigated eight active natural antimicrobials for preservation of functional beverages that are usually degraded by yeasts rather than by bacteria due to a high sugar content and a low pH. Five strains of yeasts (S. cerevisiae, Z. bailii, P. membranaefaciens, C. albicans, and P. Anomala) were tested with eight natural antimicrobial agents (ε-polylysine, yucca extract, vitamin B1 derivative, scutellaria baicalensis extract, chitooligosaccharid, allyl isothiocyanate, sucrose-fatty acid ester, and oligosaccharide). The lowest minimal inhibitory concentrations (MIC) were 10 ppm for oligosaccharide and sucrose-fatty acid ester against S. cerevisiae and Z. bailii, 10 ppm for allyl isothiocynate against P. membranaefaciens and C. albican, and 10 ppm for allyl isothiocynate and oligosaccharide against P. anomala . No growth were observed for five kinds of yeasts in functional beverages containing sodium benzonate at concentration of 0.015% or higher. The resistance of S. cerevisiae, Z. bailii, and P. Anomala against natural antimicrobial agents was lower than those of P. membranaefaciens and C. albican. Allyl isothiocyanate, oligosaccharide, and sucrose- fatty acid ester showed the highest antimicrobial activities among the eight tested antimicrobials. These results can be applied to develop new natural antimicrobial agents to improve microbial quality of functional beverages.
        3,000원
        8.
        1996.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper intends to evaluate the seakeeping performance in consideration of nominal speed loss of ships in a seaway. Authors calculate the nominal speed loss in the Sea State of Beaufort Scale 6, 7 & 8 and obtain each response amplitude of ship;s motion by New Strip Method in consideration of them. This study presents some results of the seakeeping performance by the maximum dangerouseness of ships on each sea state.
        4,000원
        9.
        2019.12 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to develop a method to assess the expected damage and loss of vehicle by flood disaster. To this end, we designed the inventory (exposure) DB to define spatial location and distribution by vehicle type, and presented the construction procedure of inventory DB. Vehicle asset value required for quantifying loss was taken into account depreciation in the replacement cost of each representative vehicles. The vehicle vulnerability curve is used to analyze the percent damage due to flood depth. It is classified the vehicle into three types based on the vehicle height, developed the vulnerability curve from the opinion of the expert group. The method proposed in this study is part of f lood loss assessment model. It will be used for flood risk assessment and economic analysis of flood mitigation projects.
        11.
        2010.05 KCI 등재 서비스 종료(열람 제한)
        본 논문은 구조물의 기초지지력에 안정성 평가를 위해서 연구되었다. 구조물의 하부에 설치된 기초의 저면은 지반과 접촉하게 되는데 지반유실 및 기타원인으로 인해 기초와 지반의 접촉면 일부분이 손실되었을 때 접촉비율에 따라 나타나는 지지력안정성을 분석하기 위해서 시행되었다. 이를 위해 기초저면과 지반의 접촉비율을 정량적으로 조절하여 수치해석 및 모형실험으로 지지력 거동을 분석한 결과 기초저면과 지반의 접촉율이 75% 이상일 경우에는 기초의 지지력이 크게 저하되지 않는다는 지지력 안정성 기준을 확립하였다.