• Environmental Analysis Health and Toxicology
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• 제19권1호
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• pp.49-58
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• 2004

It is important to select a risk based priority area for environmental policy formation and decision-making. We estimated the health risks and associated damage costs from exposure to fine particles and assigned priority areas for twenty -five districts in Seoul. In order to estimate the theoretical mortality incidence of the health risk, baseline risks were estimated from mortality rates in two low level areas of fine particles, Seocho Gu and Cheju city To estimate the damage cost from the risk estimates, we investigated and estimated the willingness to pay (WTP) for specific risk reduction. We assumed two different locations as the reference area, Cheju city as Scenario I and Seocho gu as Scenario II. From the results, the five districts, Kwangjin, Chungnang, Kangbuk, Nowon, and Kangnam, ranked high in the categories of both health risk and economic risk. Damage costs were over twenty billion won in each of these districts. As there are uncertainties in these results, the parameter values such as PM$_{2.5}$ level, dose -response slope factor, baseline risk, exposure population and WTP should be continuously validated and refined.d.

• Advances in concrete construction
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• 제16권3호
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• pp.141-153
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• 2023

In order to develop and take full advantage of pasture fiber and waste concrete, this article studied how different amounts of pasture fiber influenced the toughness and pore structure of concrete with different replacement rates of recycled fine aggregate. Pasture fiber recycled concrete constitutive equations were established under idealized stiffness and toughness damage rate, based on fracture energy and damage mechanics theories. The relationship between pore structure and toughness was studied utilizing nuclear magnetic resonance and fractal theory. The toughness of text groups (0% (JZ), 10% (ZS10), 20% (ZS20)) first increased and then decreased with increasing amounts of pasture fiber, based on the damage rate of toughness. The toughness of concrete samples with recycled fine aggregate and pasture fiber is negatively correlated to the fractal dimension of small and medium-sized pores with a pore size of 0-500 nm. At a replacement rate of 10% of the recycled fine aggregate, the fractal dimension of the air voids (r: 500-9000 nm, i.e., Lg(r) ∈ [2.7, 3.9]) shows a gradual decrease with the increase of grass fiber dosage, indicating that with such a replacement rate of the recycled fine aggregate, the increase of pasture fiber can reduce the complexity of the pore structure of the air voids (500-9000 nm).

• Earthquakes and Structures
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• 제23권3호
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• pp.259-269
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• 2022

In this study, we introduce a canonical correlation analysis method to accurately assess the tunnel damage potential of ground motion. The proposed method can retain information relating to the initial variables. A total of 100 ground motion records are used as seismic inputs to analyze the dynamic response of three different profiles of tunnels under deep and shallow burial conditions. Nine commonly used ground motion parameters were selected to form the canonical variables of ground motion parameters (GMP_CCA). Five structural dynamic response parameters were selected to form canonical variables of structural dynamic response parameters (DRP_CCA). Canonical correlation analysis is used to maximize the correlation coefficients between GMP_CCA and DRP_CCA to obtain multivariate ground motion parameters that can be used to comprehensively assess the tunnel damage potential. The results indicate that the multivariate ground motion parameters used in this study exhibit good stability, making them suitable for evaluating the tunnel damage potential induced by ground motion. Among the nine selected ground motion parameters, peck ground acceleration (PGA), peck ground velocity (PGV), root-mean-square acceleration (RMSA), and spectral acceleration (Sa) have the highest contribution rates to GMP_CCA and DRP_CCA and the highest importance in assessing the tunnel damage potential. In contrast to univariate ground motion parameters, multivariate ground motion parameters exhibit a higher correlation with tunnel dynamic response parameters and enable accurate assessment of tunnel damage potential.

• 한국환경과학회지
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• 제23권8호
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• pp.1455-1462
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• 2014

The purpose of this study is to examine green consumer behavior (green product purchasing behavior and green consumption life) affected by demographical characteristics, and cognition degree of green life (cognition of a green indicator, a green life catalyst system, and environmental problems). It's also to promote strategy and suggest effective activation plans for the vitalization of green consumer behavior. To carry out the task, verification of credibility, multiple regression analysis, two-step cluster analysis, and multinomial logistic analysis were used. The results are as follows: First, the factors that effect green product purchasing behavior were gender, age, cognitive of a green indicator, carbon points system, electricity peak hour system, and seriousness of environmental damage due to lifestyle. Second, the factors that effect green lifestyle were gender, age, carbon grade indicator system, cognition of a green system, and the seriousness of environmental damage due to lifestyle. Third, the comparative group characteristic analysis showed low rates for careless green consumer behavior groups compared to the passive green consumer behavior groups in cognition of a green indicator, green system, and environmental problems. For active green consumer behavior groups, the analysis showed high rates in cognition of carbon grades, eco-labeling, electricity peak hour system, and environmental damage due to lifestyle. In order to encourage green consumer behavior, it's evident that cognition of a green indicator, a green life catalyst system, and environmental problems need to be improved through strategic education and continuous encouragement.

• Reproductive and Developmental Biology
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• 제35권3호
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• pp.295-300
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• 2011

The objective of this study was to evaluate efficiency of methyl-beta-cyclodextrin (MBCD) in the sperm preservation of bull. For this study, the freezing of diluted semen were added with Triladyl containing 20% egg-yolk and/or 0, 1, 5, 10 and 20 mM MBCD before freezing process. Analysis of viability in frozen-thawed sperm was estimated by SYBR14/PI double stain, hypoosmotic swelling test(HOST) and acrosome damage with FITC-PNA, and mitochondria activation with Rhodamin123 by flow-cytometry. The sperm viability was significantly in 0 mM and 5 mM concentrations of MBCD than other groups (p<0.05). However, the HOST was significantly lower at 20 mM concentration of MBCD than other concentrations (p<0.05). In addition, acrosome damage and mitochondria activation rates were significantly lower at 20 mM concentration of MBCD than other groups (p<0.05). In conclusion, the viability of sperm was not significantly different among concentrations of MBCD 0, 5 and 10 mM, but MBCD 20 mM was significantly lower than other groups. In addition, as concentrations of MBCD was high, HOST, acrosome damage and mitochondria activation rates had a negative effect in bull sperm.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권1호
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• pp.43-52
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• 2010

Purpose: To research about maxillofacial traumatic injuries of children in aspects of gender difference, various incidence rates between age, trauma type, cause, monthly and daily incidence rate, type of tooth damage, gingival damage, soft tissue damage, and type of facial bone fracture. Materials and methods: Study group consisted of children under 15 years of age who visited Dental Hospital, School of Dentistry, Kyung Hee University from 2004/7/1 to 2007/6/30 with chief complaint of oral and maxillofacial traumatic injuries. 1,559 cases of traumatic injuries were studied from 1,556 (1,004 male, 552 female) children. Conclusion: 1. There were slightly more boys than girls, giving a male-to-female ratio of 1.82:1.0. The 1-3 year old boys and girls had the highest number of traumatic injuries. 2. Of the 1,556 patients, 68.63% had soft tissue injuries, 50.22% had periodontal injuries, 29.89% had teeth injuries, and 3.85% had maxillofacial bone fractures. 3. Falling down was the most common cause of injury in both sexes. 4. The months with the highest incidence rates were in order May (12.12%), June (11.74%), and October (11.13%). Most of the injuries occurred on weekends. 5. The most common tooth injury was uncomplicated crown fracture, and the most common periodontal injury was subluxation. The majority of traumatizes teeth were the upper central incisors. 6. The most common soft tissue injury was intraoral lacerations. 7. Mandibular fractures were most frequent in facial bone fractures; symphysis, condylar head, and angle fractures were most frequent in mandibular fractures; maxillary and nasal bone fractures were most frequent in midfacial bone fractures.

• Journal of Korean Society for Atmospheric Environment
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• 제19권E2호
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• pp.51-61
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• 2003

The material exposure tests have been carried out since 1993 to evaluate the relationship between air pollution and material corrosion with the cooperation of the researchers in Japan, China, and Korea. The test pieces such as bronze, copper, marble, and carbon steel have been exposed under both unsheltered and rain-sheltered outdoor condition separately at 18 sampling sites in East Asia. At the same time, the concentration of SO$_2$ and NO$_2$ has been measured simultaneously with passive sampler. The meteorological data were collected from the AWS (Auto-mated weather station) In each country and chemical compositions of wet deposition were also analyzed by the bulk sampling of rainfall every month. As the results, it was found that the corrosion rates of test pieces in the ambient air were appeared to be in the order of carbon steel > marble > bronze copper. The corrosion rates of test pieces in the unsheltered outdoor condition were 2.34 to 5.88 times larger than those in rain-sheltered condition. It was also found that the corrosion rate in the heavy polluted area in China was the highest, and the corrosion rates of the metal pieces were generally proportional to SO$_2$ concentration. Between two sites in Korea, the test pieces at Daegu site showed higher corrosion rates that would be due to the higher SO$_2$ concentration.

• Journal of the Korean Wood Science and Technology
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• 제25권4호
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• pp.92-98
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• 1997

To make good use of chitosan forming complex with heavy metals in wood preservative treatment, woods impregnated with chitosan and copper sulfate were prepared. Amounts of leached copper, decay resistance, anti-mold efficacy, iron corrosion rates, moisture regain rates and degradation pattern in chitosan pre-treated and untreated wood were compared. After leaching test, amounts of leached copper from chitosan pre-treated wood had a much smaller than chitosan untreated wood, and good decay resistance was retained even after leaching test. From these results, it was proved that chitosan-copper complex formed in wood played and important role for decay durability. In chitosan pre-treated wood, damage values by test molds became remarkably smaller, but the growth of test molds was not perfectly inhibited. Distinct differences in iron corrosion rates between chitosan pre-treated and untreated woods was not recognized but chitosan pre-treated wood showed the lower moisture regain rates than chitosan untreated wood because of water insoluble chitosan membrane formed in wood. After leaching test, the tracheid walls in the wood treated with 2.0% copper sulfate only were eroded by the fungal attacks, but those in the wood pre-treated with chitosan remained almost intact.

• 한국동물학회지
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• 제23권3호
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• pp.115-123
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• 1980

DNA 회복합성과 염색체이상과의 연관성여부를 추구하기 위하여 CHO 세포를 재료로 MNNG의 농도와 처리후 시간경과에 따른 절제회복율을 조사하고 이들 염색체 이상율과 비교하여 다음과 같은 결과를 얻었따. 1. MNNG에 의한 절제회복율은 $0.5 \\times 10^-5M$에서 $0.5 \\times 10^-5M$까지 농도의 증가에 따른 절제회복율의 증가를 보인다. 또 $1 \\times 10^-5M$ 처리후 0시간째는 절제회복율의 최고치를 보이다가 그후 점자 감소하여 24시간에는 0시간의 66%정도 나타난다. 2. MNNG에 의한 염색체이상은 $1 \\times 10^-5M$ 처리후 6시간에 최대치를 보이며 이상형의 대부분은 염색분체 절단을 나타낸다. 그러나 시간이 경과함에 따라 염색체분체절단은 감소하고 염색분체교환은 증가하여 24시간에는 두종류의 이상율이 비슷하게 이른다. 3. MNNG 처리후 시간경과에 따른 절제회복율은 전체이상율과 대체로 일치한다. 그러나 염색분체교환 또는 염색분체절단과는 어떤 비례관계도 보이지 않는다. 따라서 이같은 결과들은 MNNG에 의한 DNA 상해 및 그 회복은 염색체의 회복 현상과는 연관성이 없음을 암시하는 것이다.

• 원예과학기술지
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• 제28권6호
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• pp.990-995
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• 2010

본 시험은 이상저온($-3.5^{\circ}C$ 이하에서 7시간 지속)에 의해 수체 상에서 동결된 사과 '후지' 과실들의 수확시기에 따른 품질차이를 비교하고자 실시하였다. 수확 시기는 동결피해 1일 전, 동결피해 2일 후, 동결피해 6일 후였다. 시험에 조사된 과실들의 수확시 가용성 고형물 함량은 $14^{\circ}Bx$ 이상이었다. 동결피해 후 수확한 과실의 수확 시 경도 및 산 함량은 동결피해 전에 수확한 과실보다 낮았다. 저온저장 중의 에틸렌 발생량은 동결피해 후 수확한 과실이 동결피해 전에 수확한 과실보다 높았다. 동결피해 후 수확한 과실의 저온 저장 동안의 품질저하는 동결피해 전에 수확한 과실보다 심하였다. 동결피해 후에 수확한 과실의 저온저장 출고 후 실온 1주일째의 품질 저하는 동결피해 전에 수확한 과실보다 더 심하였다. 동결피해 후에 수확한 시험구들간의 비교에서는 저온저장 8주까지 동결피해 6일 후에 수확한 시험구의 에틸렌 발생량 및 과실품질 저하가 동결피해 2일 후에 수확한 시험구보다 낮았으나, 이러한 차이는 저온저장 8주 이후로는 없었다. 과육 갈변증상 발생률은 $-3.5^{\circ}C$ 이하에서 7시간 동결될 경우 영향을 받지 않은 것으로 나타났다.