• 콘크리트학회논문집
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• 제18권2호
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• pp.233-238
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• 2006

본 연구에서는 염해환경에 노출되어 있는 철근콘크리트 구조물의 수명예측에 있어서 철근덮개 파괴시간 예측을 위하여, 유한요소해석을 통한 방법을 제시하였다. 또한 본 연구에서는 인공세공용액중의 철근 부식속도로부터 콘크리트 중의 철근 부식속도를 유도하는 방법을 제시하였으며, 철근 부식의 분포에 따른 철근덮개의 파괴시간을 비교하여, 철근덮개 파괴시간을 합리적으로 예측하기 위한 방법을 제시하였다. 국부부식을 고려한 경우 균일한 부식을 가정한 경우보다 최대 약 40%정도 철근덮개 파괴시간이 짧아짐을 알 수 있다. 따라서, 철근덮개의 파괴시간 예측을 위한 유한요소해석에 있어서 국부부식을 고려하는 것이 합리적인 결과를 제시할 수 있을 것으로 사료된다.

• 한국어병학회지
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• 제30권1호
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• pp.51-61
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• 2017

The effect of electromagnetic field on aquatic organisms has received little attention. In the current study, the effect of 50Hz electromagnetic field on muscle histopathology of Caspian Sea Cyprinus carpio, a species of economic importance, was investigated. A total of 120 healthy fish were used in this study. They were classified randomly in one of two groups as follows: Control or unexposed EMF group and experimental group with 5 different magnetic field intensities (0.1, 1, 3, 5 and 7mT) at 2 different exposure times including 30 and 60 minutes. Fish in the experimental group were exposed only once. Two weeks after exposure, dorsal muscles sectioned transversely, stained and were examined using a light microscope. Histopathologic assessments showed significant difference between control and EMF exposed groups at both 30 min. (p<0.01) and 60 min. (p<0.001) exposure times. We report for the first time that electromagnetic field in interaction with muscular tissue of Cyprinus carpio exhibits a dual effect which depends on the field intensity, and exposure time. At short exposure time (30 min.), EMF stimulates muscle growth process. At longer exposure time (60 min.), EMF can damage muscle tissue and result in muscle necrosis. More research is required to elucidate precise mechanisms involved in muscle hypertrophy and pathologic changes.

• 한국패류학회지
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• 제29권3호
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• pp.225-232
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• 2013

본 연구는 저염분 해수에 노출된 전복의 폐사 원인을 구명하고자, 수온별 (15, 20 및 $25^{\circ}C$) 염분별 (30, 25, 20 및 15 psu) 노출시간별 (3, 6, 12, 24 및 48 h) 북방전복, Haliotis discus hannai 치패의 회복률 및 아가미의 조직학적 변화를 조사하였다. 모든 수온조건에서 20 psu 이하의 저염분 해수에 6시간 이상 노출시킨 전복은 회복기간 동안 생존율이 감소하였으며, 15 psu 해수에 24시간 이상 노출시킨 전복은 회복되지 못하고 전량 폐사하였다. 이를 조직학적으로 관찰한 결과, 20 psu 이하의 저염분 해수에 6시간 이상 노출시킨 전복의 아가미 조직은 팽창 또는 손상되었으며, 15 psu 해수에 24시간 이상 노출시킨 전복의 아가미 조직은 대부분 파괴되었다. 이와같은 결과는 수온이 높을수록, 염분이 낮을수록, 노출시간이 길수록 확연히 나타났다. 따라서 저염분 해수에 노출된 전복이 폐사하는 직접적인 원인 중의 하나는 아가미 조직의 손상으로 인한 질식으로 판단된다.

• 한국심리학회지:법
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• 제11권2호
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• pp.173-190
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• 2020

본 연구는 자서전적 암묵적 연합 검사(aIAT)를 이용하여 범죄 정보에 노출된 무고한 용의자와 유죄 용의자를 변별할 수 있는지 모의 범죄 패러다임을 통해 검증하고자 했다. 총 49명의 대학생을 유죄 집단, 무죄-범죄 정보 노출 집단, 무죄-범죄 정보 비노출 집단에 각각 무선 할당하였다. 참가자는 모의 범죄 또는 통제 과제 수행 후 용의자 색출을 위한 aIAT를 수행하였다. 유죄 및 무죄 문장과 진실 문장 간의 연합의 강도를 환산한 D 점수와 반응 시간을 통해 범죄 정보에 노출된 무고한 용의자와 유죄 용의자를 변별할 수 있는지 검증하였다. 분석 결과, 유죄 집단은 무죄-범죄 정보 노출 집단과 무죄-범죄 정보 비노출 집단보다 유의하게 높은 D 점수를 나타냈으며, 진실-무죄 조건보다 진실-유죄 조건에서 빠른 반응시간을 보였다. 이는 진실-유죄 조건의 연합이 진실-무죄 조건의 연합보다 크다는 것을 보여준다. 반면, 무죄-범죄 정보 노출 집단은 진실-유죄 조건보다 진실-무죄 조건에서 빠른 반응시간을 보였으며, 무죄-범죄 정보 비노출 집단은 두 조건 간 유의한 차이가 없는 것으로 나타났다. 이를 통해, 범죄 정보에 노출된 무고한 용의자가 유죄 집단에 비해 진실과 무죄 연합에서 빠른 반응속도를 보이는 aIAT 패턴에 따라 변별될 수 있음을 확인했다. 본 연구는 범죄 정보에 노출된 용의자를 aIAT를 활용하여 효과적으로 변별할 수 있음을 확인하였으며, 나아가 거짓말 탐지 분야에서 aIAT가 지닌 유용성과 가능성을 제안한다.

• 한국환경과학회지
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• 제2권2호
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• pp.123-133
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• 1993

Shingal reservoir is a relatively small (211ha) and shallow impoundment, and approximately 25 ha of its sediment is exposed after spring drawdown. At least 14 vascular p13n1 species germinate on the exposed sediment, but Persimria vulgaris Webb et Moq. quickly dominates the vegetation. In order to estimate the role of the vegetation in the dynamics of heavy metal pollutants in the reservoir, Cu concentration of water, fallout particles, exposed sediment, and tissues of p. vulgaris, Ivas analyzed. Cu content in reservoir water decreased from $13.10mg/m^2$ on May 15 (before dralvdown) to $3.08mg/m^2$ in June 1 (after drawdown), mainly due to the loiwering of water level. Average atmospheric deposition of Cu by fallout particles was $10.84 {\mu}g/m^2/day$. Cu content in the surface 15cm of exposed sediment decreased from $5.094g1m^2$ right after drawdown, to $0.530g/m^2$ in 41 days, which is a 89.6% decrease. Therefore up to 99.7% of Cu in the reservoir appears to exist in the sediment. only 0.3% in water If the rate of atmospheric Input by fallout particles is assumed to have been the same since 1958, when the reservoir was completed, cumulative input of Cu during the 38 years would have been $150.35mg/m^2$, which is only 3.0% of Cu content in sediment right after drawdown. Therefore, most of Cu in the Shingal reservoir must have been transported by the Shingal-chun flowing into the reservoir, Standing crop of vegetation on the exposed sediment 41 days after drawdown was $730.67g/m^2$, of which 630.91g/m2 was p. vulgaris alone, and Cu content in P vulgaris at this time was $6.612mg/m^2$. This was only 0.13% of Cu in the exposed sediment, but was 50.5% of Cu in water before drawdown, or 167% of the average annual input of Cu by atmospheric deposition. If other plants were assumed to absorb Cu to the same concentration as p. vulgaris, total amount of Cu absorbed in 41 days by vegetation on the exposed sediment is estimated to be 1913.3 g, which is a considerable contribution to the purification of the reservoir water.

• 한국환경과학회지
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• 제2권2호
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• pp.29-29
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• 1993

Shingal reservoir is a relatively small (211ha) and shallow impoundment, and approximately 25 ha of its sediment is exposed after spring drawdown. At least 14 vascular p13n1 species germinate on the exposed sediment, but Persimria vulgaris Webb et Moq. quickly dominates the vegetation. In order to estimate the role of the vegetation in the dynamics of heavy metal pollutants in the reservoir, Cu concentration of water, fallout particles, exposed sediment, and tissues of p. vulgaris, Ivas analyzed. Cu content in reservoir water decreased from $13.10mg/m^2$ on May 15 (before dralvdown) to $3.08mg/m^2$ in June 1 (after drawdown), mainly due to the loiwering of water level. Average atmospheric deposition of Cu by fallout particles was $10.84 {\mu}g/m^2/day$. Cu content in the surface 15cm of exposed sediment decreased from $5.094g1m^2$ right after drawdown, to $0.530g/m^2$ in 41 days, which is a 89.6% decrease. Therefore up to 99.7% of Cu in the reservoir appears to exist in the sediment. only 0.3% in water If the rate of atmospheric Input by fallout particles is assumed to have been the same since 1958, when the reservoir was completed, cumulative input of Cu during the 38 years would have been $150.35mg/m^2$, which is only 3.0% of Cu content in sediment right after drawdown. Therefore, most of Cu in the Shingal reservoir must have been transported by the Shingal-chun flowing into the reservoir, Standing crop of vegetation on the exposed sediment 41 days after drawdown was $730.67g/m^2$, of which 630.91g/m2 was p. vulgaris alone, and Cu content in P vulgaris at this time was $6.612mg/m^2$. This was only 0.13% of Cu in the exposed sediment, but was 50.5% of Cu in water before drawdown, or 167% of the average annual input of Cu by atmospheric deposition. If other plants were assumed to absorb Cu to the same concentration as p. vulgaris, total amount of Cu absorbed in 41 days by vegetation on the exposed sediment is estimated to be 1913.3 g, which is a considerable contribution to the purification of the reservoir water.

• 한방재활의학과학회지
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• 제21권1호
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• pp.35-46
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• 2011

Objectives : The present study investigated inflammatory effect of Rheum undulatum L. in lipopolysaccharide-exposed rats and Raw 264.7 cells. Methods : Male rats weighting $185.39{\pm}8.21g$ fed basal diet for 1 week and 32 rats were divided into a control group and 3 experimental groups. We fed a control group of rats a basal diet and administered normal saline(100 mg/kg, 1time/1day) for 6 weeks. And we fed basal diet and administered an extract of Rheum undulatum L.(100 mg/kg, 200 mg/kg, 300 mg/kg, 1time/1day) to each experimental group of rats. We measured the plasma concentration of $IL-1{\beta}$($interleukin-1{\beta}$), IL-6 and $TNF-{\alpha}$(tumor necrosis $factor-{\alpha}$), liver cytokines, Raw 264.7 macrophages cytokines. Results : The plasma concentration of $IL-1{\beta}$, IL-6 and $TNF-{\alpha}$ peaked at 5h(hour) after LPS(lipopolysaccharides) injection, and the values of the Rheum undulatum L. extract groups were lower than those of the control group. In the increment of these cytokines concentration at 2h and 5h after LPS injection, the Rheum undulatum L. groups were lower than that of control group. The plasma concentration of IL-10 peaked at 5h after LPS injection, and the values of the Rheum undulatum L. extract groups were higher than those of the control group. In the increment of this cytokine concentration at 2h and 5h after LPS injection, the Rheum undulatum L. groups were higher than that of control group. Liver cytokines measurement was done at 5h after LPS injection. The concentration of liver $IL-1{\beta}$ and IL-6 in the Rheum undulatum L. groups was lower than that of the control group. The concentrations of liver $TNF-{\alpha}$, and IL-10 showed no significant differences among all the treatment groups. In the studies of lipopolysaccharide-exposed Raw 264.7 cells, the concentration of $IL-1{\beta}$, IL-6 and $TNF-{\alpha}$ in the lipopolysaccharide-exposed cells groups was higher than that of control group(normal group), and in the lipopolysaccharide-exposed cells groups, these values showed a tendency to decrease in the Rheum undulatum L. groups. The concentration of IL-10 in the lipopolysaccharide-exposed cells groups was higher than that of control group(normal group), and in the lipopolysaccharide-exposed cells groups, the values showed a tendency to increase in the Rheum undulatum L. groups. Conclusions : These results indicate that the Rheum undulatum L. extracts have an functional material for inflammatory activities.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.508-526
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• 1995

This experiment was performed to study mechanisms of desensitization by chemical desensitizing agents in hypersensitive dentin and compare effects of these agents by measuring the activity of intradental nerves and observing their occluding aspects on dentinal tubules with SEM over time after application of chemical desensitizing agents to the exposed dentinal surfaces. Canines of adult cats weighing 2-3 kg were cross-sectioned at 1.5 mm from incisal apex, and the smear layer of the exposed dentinal susface was removed by 32 % $H_3PO_4$ for 15 sec. Chemical desensitizing agents such as 10% $SrCl_2$, 5% $KNO_3$ and 30% $K_2C_2O_4$, were applied to the exposed dentin surfaces for 2 minutes. Intradental nerve activity was measured immediately after application of the agents, at 15 minutes and at 30 minutes by stimulating with 4M NaCl. To compare occluding ability of desensitizing agents on dentinal tubules in vivo and in vitro, the structures of the exposed dentinal surfaces of nonvital and vital teeth were morphologically observed by SEM. The results obtained were as follows : 1. Intradental nerve activity was decreased immediately after the application of 10 % $SrCl_2$, 5% $KNO_3$ and 30% $K_2C_2O_4$. (p<0.01), among which 30% $K_2C_2O_4$. showed the highest desensitizing effect(p<0.01). 2. The immediately decreased intradental nerve activity after application of 10 % $SrCl_2$ and 5% $KNO_3$ was increased over time. 10% $SrCl_2$ and 5% $KNO_3$ showed no desensitizing effect respectively at 30 minutes and at 15 minutes after application. 3. The immediately decreased intradental nerve activity after application of 30 % $K_2C_2O_4$ was persistently continued during the period of observation (p<0.01). 4. Precipitates of $SrCl_2$ and $KNO_3$ were not noted on the exposed dentinal surfaces and within dentinal tubules by SEM examination. On the other hand, 30 % $K_2C_2O_4$ produced precipitates on the exposed dentinal surfaces and openings of dentinal tubules without any formed preciptates within dentinal tubules. 5. Ten percent $SrCl_2$, 5 % $KNO_3$ and 30 % $K_2C_2O_4$ showed no differences in their occluding aspects on dentinal tubules either in vivo or in vitro studies and either immediately following application or at 30 minutes. These results suggest that the desensitizing effect of $SrCl_2$ and $KNO_3$ is resulted from their reducing effect on the intradental nerve activity rather than from their precipitates' occluding the dentinal tubules. However, desensitizing effect of 30 % $K_2C_2O_4$, is probably resulted from its precipitates' occluding the openings of the dentinal tubules as well as from it's reducing effect on the intradental nerve actibity.

• Agribusiness and Information Management
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• 제6권2호
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• pp.24-31
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• 2014

This paper is a study on what kind of effect non-verbal communication in mobil electronic commerce has on purchase intention and visual attention. For this purpose, the screen of mobile shopping mall produced arbitrarily was exposed to the experimental group and the control group. The experimental group was exposed to the screen of mobile shopping mall that expressed non-verbal communication making use of cinemagraph images and the control group was exposed to the screen of mobile shopping mall based on still images. For the study, survey research and experimental research were conducted simultaneously. Data of survey research were analyzed by MANOVA and t-test, and by using eye-tracker experimental research recorded the duration of time that the subjects stared images. The results of experiment show that in non-verbal communication the experimental group that saw cinemagraph images recorded shorter average staring time than the control group that saw ordinary images, and the cinemagraph had statistically significant effect on visual attention as well. And it was analyzed that non-verbal communication had significant effect on the purchase intention of the experimental group, but had no effect on the purchase intention of the control group. The results can be interpreted that the people who saw cinemagraphs in mobile shopping environment had spent shorter time in seeing products than the people who saw ordinary images, but still the former came to have purchase intention on the products. The results of the present study can be useful for marketers who try to sell agrifood in mobile environment.

• BMB Reports
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• 제36권1호
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• pp.1-11
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• 2003

The causative role of polycyclic aromatic hydrocarbons (PAH) in human carcinogenesis is undisputed. Measurements of PAH-DNA adduct levels in easily accessible white blood cells therefore represent useful early endpoints in exposure intervention of chemoprevention studies. The successful applicability of DNA adducts as early endpoints depends on several criteria:i.adduct levels in easily accessible surrogate tissues should reflect adduct levels in target-tissues, ii. toxicokinetics and the temporal relevance should be properly defined.iii. sources of inter- and intra-individual variability must be known and controllable, and finally iv. adduct analyses must have advantages as compared to other markers of PAH-exposure. In general, higher DNA adduct levels or a higher proportion of subjects with detectable DNA adduct levels were found in exposed individuals as compared with non-exposed subjects, but saturation may occur at high exposures. Furthermore, DNA adduct levels varied according to changes in exposure, for example smoking cessation resulted in lower DNA adduct levels and adduct levels paralleled seasonal variations of air-pollution. Intra-individual variation during continuous exposure was low over a short period of time (weeks), but varied significantly when longer time periods (months) were investigated. Inter-individual variation is currently only partly explained by genetic polymorphisms in genes involved in PAH-metabolism and deserves further investigation. DNA adduct measurement may have three advantages over traditional exposure assessment: i. they can smooth the extreme variability in exposure which is typical for environmental toxicants and may integrate exposure over a longer period of time. Therefore, DNA adduct assessment may reduce the monitoring effort. ii. Biological monitoring of DNA adducts accounts for all exposure routes. iii. DNA adducts may account for inter-individual differences in uptake, elimination, distribution, metabolism and repair amongst exposed individuals. In conclusion, there is now a sufficiently large scientific basis to justify the application of DNA adduct measurement as biomarkers in exposure assessment and intervention studies. Their use in risk-assessment, however, requires further investigation.