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        검색결과 42

        2.
        2022.10 구독 인증기관·개인회원 무료
        Organic scintillator is easy to manufacture a large size and the fluorescence decay time is short. However, it is not suitable for gamma measurement because it is composed of a low atomic number material. Organic scintillation detectors are widely used to check the presence or absence of radiation. The fluorescence of organic scintillators is produced by transitions between the energy levels of single molecules. In this study, an organic scintillator development study was conducted for use in gamma measurement, alternative materials for secondary solute used in basic organic scintillators were investigated, and the availability of alternative materials, detection characteristics, and neutron/gamma identification tests were performed. In other words, a secondary solute showing an improved energy transfer rate than the existing material was reported, and the performance was evaluated. 7-Diethylamino -4-methylcoumarin (DMC), selected as an alternative material, is a benzopyrone derivative in the form of colorless crystals, has high fluorescence and high quantum yield in the visible region, and has excellent light stability. In addition, it has a large Stokes shift characteristic, and solubility in solvent is good. Through this study, it was analyzed that the absorption wavelength range of DMC coincided with the emission wavelength range of PPO, which is the primary solute. Through this study, it was confirmed that the optimal concentration of DMC was 0.04wt%. As a result of performing gamma and neutron measurement tests using a DMC-based liquid scintillator, it showed good performance (FOM=1.42) compared to a commercial liquid scintillator. Therefore, the possibility of use as a secondary solute was demonstrated. Based on this, if studies on changes in the composition of secondary solute or the use of nanoparticles are conducted, it will be possible to manufacture and utilize a scintillator with improved efficiency compared to the existing scintillator.
        3.
        2022.10 구독 인증기관·개인회원 무료
        The safe, efficient and cost-effective decommissioning and dismantling of radioactive facilities requires the accurate characterization of the radionuclide activities and dose rate environment. And it is critical across many nuclear industries to identify and locate sources of radiation accurately and quickly. One of the more challenging aspects of dealing with radiation is that you cannot see it directly, which can result in potential exposure when working in those environments. Generally, semiconductor detectors have better energy resolution than scintillation detectors, but the maximum achievable count rates are limited by long pulse signals. Whereas some high pure germanium detectors have been developed to operate at high count rates, and these HPGe detectors could obtain gamma-ray spectra at high count rates exceeding 1 Mcps. However, HPGe detectors require cooling devices to reduce the leak currents, which becomes disadvantageous when developing portable radiation detectors. Furthermore, chemicalcompound semiconductor detectors made of cadmium telluride and cadmium zinc telluride are popular, because they have good energy resolution and are available at room temperature. However, CdTe and CZT detectors develop irradiation-induced defects under intense gamma-ray fields. In this Review, we start with the fundamentals of gamma rays detection and review the recent developments in scintillators gamma-ray detectors. The key factors affecting the detector performance are summarized. We also give an outlook on the field, with emphasis on the challenges to be overcome.
        6.
        2019.04 구독 인증기관·개인회원 무료
        우리나라에서 흰등멸구는 매년 해외로부터 비래, 정착한 후 2~3세대를 경과하며 벼의 생육 및 품질 저하에 영향을 미치는 벼의 중요 해충 중 하나이며, 비래해충의 경우 비래 후 세대에 따른 변화 양상을 정확하게 예측하는 것은 방제시기와 방제수단을 결정하는데 중요하다. 공시충은 2018년 사육실에서(25±2 ℃, 60±5% RH, L:D=16:8) 누대사육하여 사용하였다. 흰등멸구가 국내에 비래 후 3세대까지 세대증식하면서 피해를 주는 것으로 가정하여 1세대와 3세대 간의 발육과 산란 등을 조사하였으며 얻어진 결과를 토대로 생명표를 작성하였다. 약충기간은 1세대와 3세대에서 각각 14.5일, 13.6일, 암컷 성충기간은 각각 17.2일, 11.8일로 나타났으며, 우화율은 98.3%, 85.0%로 조사되었 다. 산란기간은 각각 6.8일, 6.0일이었으며 산란수는 47.5마리, 122.6마리로 세대가 늘어나면서 증가하는 것으로 나타났다. 생명표 분석 결과, 순증가율, 내적자연증가율이 각각 5배, 1.7배 증가한 것으로 나타났다.
        8.
        2017.06 구독 인증기관 무료, 개인회원 유료
        Anthriscus sylvestris (L.) Hoffm. is a perennial herb found widely distributed in various regions of Korea, Europe, and New Zealand. The root of A. sylvestris have been extensively used in the treatment for antitussive, antipyretic, cough remedy in Oriental medicine, but the physiologically active function of the leaf of A. sylvestris is as yet unknown. In this study, we investigated the anti-cancer activity and the mechanism of cell death of water extracts of leaf of Anthriscus sylvestris (WELAS), on human FaDu hypopharyngeal squamous carcinoma cells. Our data showed that WELAS treatment inhibited cell viability in a concentration- and time-dependent manner. In addition, the treatment of WELAS markedly induced apoptosis in FaDu cells, as determined by the viability assay, DAPI stain and FACS analysis. WELAS also increased the proteolytic cleavage of procaspase-3, -9 and PARP (poly(ADP-ribose) polymerase). In addition, exposure to WELAS decreased the expression of Bcl-2 (an anti-apoptotic factor), but increased the expression of Bax (a pro-apoptotic factor), suggesting that mitochondria-dependent apoptotic pathways are mediated in WELAS-induced apoptosis. Taken together, these results indicate that water extracts of leaf of A. sylvestris inhibits cell growth and induces apoptosis via the mitochondrial-dependent apoptotic pathway in FaDu human hypopharyngeal squamous carcinoma cells. Therefore, we propose that the water extracts of leaf of A. sylvestris is a novel chemotherapeutic drug, having growth inhibitory properties and induction of apoptosis in human oral cancer cells.
        4,000원
        9.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the antidiabetic effect of amaranth grain ethanol extract (AEE) in a diabetic animal model, db/db mouse. The mice were divided into 4 groups: normal control mice (C57BL/6J), diabetic mice (C57BL/6J db/db), diabetic mice fed a lower concentration of AEE (0.3 mg/kg), and diabetic mice fed a higher concentration of AEE (0.5 mg/kg). After 10 weeks of treatment, body weights, blood insulin levels and blood glucose levels of each group were compared. At the end of treatment, the results showed that both AEE supplemented groups had lower body weights than those in the diabetic groups although higher than those in the normal groups. Moreover, in both AEE supplemented groups, serum insulin levels were higher and blood glucose levels were lower than those in the diabetic groups although both values were higher than those in the normal groups. The results of this study suggest that AEE can alleviate many of the common symptoms of diabetes in diabetic mice and, therefore, has potential as a therapeutic supplement for normalization of blood glucose and insulin levels in humans.
        4,000원
        11.
        2015.06 구독 인증기관 무료, 개인회원 유료
        Backed by the rapidly-growing economy, China sends the most tourists to Korea. Accordingly, growing consumption of Chinese tourists is strongly drawing attention of the Korean retail industry. Academia has conducted more relevant researches, such as effective branding of Korean Wave, and services to attract tourists. Despite a series of efforts, including specialized tour products and language services, there have been an increasing number of Chinese visitors complaining about their experience in Korea and Chinese tourists are urgently demanding improvements. Hence, comprehending sophisticated consumption behavior of Chinese tourists is becoming more important than ever before. Also, it needs to explore how shopping experiential value that they experience while purchasing fashion goods in Korea affects their satisfaction of the store and product. Previous literature has shown that perceived shopping value has a positive effect on customer satisfaction and behavioral intention (Mathwick et al., 2001). Previous domestic studies that targeted Chinese tourists have focused on investigating the shopping motivation and satisfaction (Ko, 2011) and market segmentation of Chinese tourist shoppers (Oh, 2014). Previous studies have approached this problem mainly from its cognitive aspect and few studies have focused on the emotional aspect during shopping. This study suggests that emotional behavior mediates the relationship between shopping experiential value and consumer attitude toward products and stores. According to the Korea Tourism Organization, the ratio of male to female Chinese tourists visiting Korea changed from 69:31 in 1995 to 59:41 in 2005. In 2013, female Chinese tourists outnumbered males at a ratio of 41:59. The number of Chinese female tourists continues to increase. Females are known to be more involved in fashion consumption. Hence, this study is conducted on 550 Chinese female tourists who have shopping experiences during their visit to Korea. The ages of the respondents range from 20 to over 50 years old, with a mean age of 33.5 years. Their shopping experiential value is measured by visual appeal, crowding, economic benefits, and service excellence, and is expected to trigger emotions of entertainment and escapism. Variables including entertainment and escapism are measured using the Experiential Value Scale developed by Mathwick et al. (2001). This study finds that three experiential values (visual appeal, crowding, and service excellence) have positive influences on entertainment. For example, customers feel greater entertainment when visual appeal, service excellence and/or the number of customers in the store is greater. The emotion of entertainment turns out to have positive impacts on both store satisfaction and product satisfaction. According to the examination of how shopping experiential values affect escapism, crowding and economic benefits have a positive impact, whereas visual appeal and service excellence have a negative impact on escapism. Previous studies define escapism as an emotion of which customers are absorbed by entertaining activities and satisfied with shopping. This study assumes that all the shopping experiential values may have a positive impact on escapism. Escapism is a status where customers are deeply occupied with shopping without thinking of anything as if they were in another world, and a much stronger emotion of entertainment than usual pleasure from shopping. This study finds that the higher visual appeal and service excellence tends to generate the lower the escapism. This may be attributable to the fact that the survey was examined only on Chinese tourists. The respondents were asked to recall the most memorable item among the fashion products that they purchased during their visit to Korea. Their shopping experiences varied widely from well-organized malls, like department stores and duty free shops, to crowded environments, like Dongdaemun, traditional markets and subway stores. As a result, different experiential values have different impacts on escapism. Economic benefits and crowding which are experienced during shopping help to absorb in shopping, and these are likely to have positive impacts on escapism. On the other hand, visual appeal and service excellence may have different influences on escapism according to the shopping environment that Chinese consumers experienced. For example, Dongdaemun or subway stores are less visually appealing than department stores or duty free shops, but trigger stronger sense of escapism. Because survey questions to measure service excellence include Chinese (language) proficiency of sales staff, it is expected that higher language proficiency level of sales staff tends to generate lower degree of escapism, the sense of feeling that one is indeed in foreign country like Korea, for customers. Escapism has negative impacts on both product and store attitudes. Escapism is a status of absorption in which customers are emotionally occupied with pleasant feelings, and purchases along with a high escapism are likely to be less rational and more impulsive. In particular, this study examines tourist shoppers, and the respondents evaluate products they purchased in another country after they return home, and this may have caused the negative attitude toward products and shops. In fact, some previous studies found that overly positive emotions have negative impacts on purchase behavior (Liljander &Standvik, 1997; Andrade, 2005). This study confirms that the shopping experiential values perceived by Chinese tourists affect their product and store attitudes through the emotions of entertainment and escapism. It is particularly notable that this study verifies diverse roles of different emotions such as entertainment and escapism in the context of tourist shopping. This study employs empirical analysis on tourists, and provides practical implications including the importance of shopping experiential values for developing retail strategies.
        3,000원
        12.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to test the effect of Gastrocnemius and Low Back-muscle isotonic exercise on static•dynamic standing balance during the period of 4 weeks. This study was two groups pretest-posttest design. Nineteen subjects who were over 22 years old were randomly assigned to either the experimental group that received the Gastrocnemius muscle exercise(n=9) or the low back muscle exercise(n=10) : The former group performed isotonic exercise(plantar flexion), the latter group performed isotonic exercise(trunk extension) a total of 18 times for three times per week for four weeks. Two groups also performed static and dynamic balance before the exercise and 4weeks after the exercise. The data were analyzed by using the paired t-test and independent t-test. The results were as follows: As compared with change of dynamic balance performance capacity at two groups, a significant difference was shown in the test(p<.05), but not in static balance(p>.05). Also, a significant difference of balance between groups was not shown in the test. In this study indicated that gastrocnemius and low back muscle isotonic exercise will have positive impact on standing balance.
        4,000원
        13.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        신선편의 샐러드와 유기농 채소에 오염되어 있는 식중독균인 B. cereus, S. aureus 그리고 E. coli를 대상으로 살균 소독제와 유기산에 대한 감수성을 평가하여 신선편의 식품의 미생물학적 안전성의 확보를 위한 올바른 세척제와 사용량을 제시하고자 하였다. S. aureus는 2% acetic acid, malic acid, tartaric acid와 1% CaO에 대하여 고농도의 염소계, 과산화수소계 보다 높은 살균 효과를 보였고 E. coli의 경우에는 1% acetic acid 와 CaO처리에 의해 80%의 분리주가 감소하여 50%에탄올과 400 ppm 차아염소산나트륨과 대등한 감소율을 보였다. B. cereus 분리주에 대한 1% CaO, 0.5% acetic acid, 2% malic acid와 tartaric acid 처리는 200 ppm의 차아염소산나트륨보다 높은 감소율을 나타내었고, 1%의 과산화수소와 대등한 감소율을 나타내었다. 본 연구에 따라 천연 물질 유래 살균 소독제인 CaO와 유기산은 기존의 화학적 살균제를 대체할 수 있는 천연 살균 소독제로 활용 될 수 있을 것이고 특히 환경 친화적이고 안전한 유기산은 고품질의 신선편의 채소를 안전성으로 공급하는데 효과적인 것으로 판단되었다.
        4,000원
        14.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Purpose: The purpose of this study was to estimate the effects of subliminal music with balance imagery training on balance and concentration. Methods: The participants were 45 seniors in an undergraduate school in Korea. The subliminal music with balance imagery training intervention was carried out for 20 minutes. Other interventions were also carried out for 20 minutes. 12 seniors(Group A) listened to subliminal music with balance imagery training, 12 seniors(Group B) listened to subliminal music, 11 seniors(Group C) received balance imagery training, and 10 seniors(Group D) had no intervention(Control group). The grid test is related to measured levels of concentration intensity. Romberg one legged standing test was carried out for 30 seconds. The collected data was analyzed by one-paired t test and one way ANOVA using the SPSS Windows 12 ver. program. Results: The major findings of this study were as follows: Concentration levels of Group A and C improved, and balance levels of Group C and D improved. There was a statistically significant decrease in concentration between Group A and B, Group A and C after intervention. Conclusion: These findings suggest that listening to subliminal music with balance imagery training may be useful in managing concentration in seniors. So it provides basic information for further concentration on improving education on music with balance imagery training.
        4,000원
        15.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study has been conducted on the subjects of eight undergradu˗ ate students with abdominal obesity and eight undergraduate stu˗ dents with normal weight to find out correlation between substantial fatigue and Ratings of perceived exertion through analysis of their blood components when they took exercises to strengthen their abdominal muscular power. Comparatively analyzing HDL-C, LDL-C and lactic acid before and after they took sit-up at level of RPE 19-20, no statistically significant differences in HDL, LDL, lactic acid meas˗ ures were observed between groups, but a significant difference in RPE was noted between groups(p<0.05) Our findings suggest that control group showed no significant differ˗ ence in increase of fatigue material whereas the obese group showed a lower frequency of sit-up, though both groups took the same abdominal exercise. Additionally, the lower frequency of sit-up in obese group results from relatively higher Ratings of perceived exer˗ tion rather than increase of substantial fatigue material. This study invites future research that examines the effect of a comprehensive obesity exercise program combined with dietetic
        4,000원
        16.
        2008.09 구독 인증기관 무료, 개인회원 유료
        Cementum is the mineralized tissue of the tooth. It is similar to bone in several aspects but it differs from bone. Human bone marrow stromal cells (BMSC) and human cementum derived cells (HCDC) (10,000 cells/cm²) were plated in 6 well plates as feeder cells. The next day, mouse bone marrow cells (1.5 million cells/cm²) were added. One group of these plates were incubated in serum-free conditioned medium (SFCM) generated from BMSC or HCDC supplemented with 2% FBS, parathyroid hormone (PTH), 1, 25 dihydroxyvitamin D₃ (Vit. D₃) and dexamethasone, or plain medium with the same supplements. Another group of plates were cocultured with BMSC or HCDC in plain medium supplemented with 2% FBS, PTH, Vit. D₃and dexamethasone. Plates grown without SFCM or coculture were used as controls. After 10 days, the cells were stained for tartrate-resistant acid phosphatase (TRAP). BMSC were found to support osteoclast formation under normal conditions. This was inhibited however by both SFCM generated from HCDC and also by coculture with HCDC. In addition, HCDC themselves did not support osteoclast formation under any conditions. Our results thus indicate that HCDC do not support osteoclast formation in vitro and that soluble factor (s) from HCDC may inhibit this process. In addition, we show that this inhibition also involves an active mechanism that is independent of osteoprotegerin, a feature that may distinguish cementoblasts from other cells present in periodontium.
        3,000원
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