• KSBB Journal
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• 제14권3호
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• pp.315-321
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• 1999

The relationships between the explosive 2,4,6-trinitrotoluene (TNT) degradation by Stenotrophomonas maltophilia and several relevant physicochemical environmental parameters were examined. At neutral pH of the cultures, the degradation of TNT proceeded to completion, whereas only about 50% of TNT was utilized when the cultures were adjusted to acidic pH. The effect of various co-substrates (e.g., glucose, fructose, acetate, citrate, succinate) on the degradation of TNT by the test culture of S. maltophilia was evaluated. The results indicated that, among the various co-substrates studies, the test culture that received 2 mM fructose degraded 100 mg/L of TNT completely within 20 days of incubation at ambient temperature, whereas partial degradation of TNT was observed in the test culture with acetate, citrate, or succinate as a co-substrate, respectively. In fact, fructose was the best co-substrate for TNT degradation in this experiment. The effect of supplemented nitrogens [e.g., (NH$_4$)$_2$,SO$_4$, NH$_4$Cl. urea] on the TNT degradation was monitored. All supplemented nitrogens in this study were inhibitory to TNT degradation. Addition of 1% Tween80 accelerated TNT degradation, and showed complete degradation of TNT within 8 days of incubation. Addition of yeast extract resulted higher growth yields, based on turbidity measurement, but it inhibited TNT degradation.

• 대한안전경영과학회지
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• 제22권3호
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• pp.53-60
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• 2020

This study aims to find the causal relationship between the effects of apartment inhabitants' life management and administrative management on housing satisfaction. The study results are as follows. Firstly, life management showed to have a positive effect on life satisfaction. In other words, the better the management of public order and facilities, the higher the satisfaction of housing satisfaction. Thus, the principal agent of management needs to increase inhabitants' housing satisfaction through education and training on developing life management techniques. Secondly, administrative management showed to have a positive effect on life satisfaction. Thus, the more accurate the completion documents and management transfer process necessary for administrative management, the higher the cost-cutting effects of accounting, construction, and service contracts, the more transparent the resident agreement process in accordance with management policies, the more transparent the election process of building representatives and resident representatives, and the higher the effects of energy saving, the higher the housing satisfaction of inhabitants. This revealed that the principal agent of management needs to increase housing satisfaction through education and training on developing administrative management techniques because the level of administrative management had a positive effect on housing satisfaction. As a result, in order to create reliability between inhabitants and the principal agents of management, the transparency of administrative management such as document disclosure must be ensured, thus improving the housing satisfaction of inhabitants.

• 한국지반신소재학회논문집
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• 제2권3호
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• pp.47-55
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• 2003

본 고에서는 성균관대학교에 시공된 시험옹벽의 계측결과와 국외에서 발표된 옹벽 붕괴사례를 토대로 강우가 보강토 옹벽의 거동에 미치는 영향을 검토하였다. 시험옹벽에서의 계측결과에서는 집중강우 발생시 벽체 변위 및 보강재의 유발변형율이 증가하는 추세가 뚜렷하게 관찰 되었다. 한편 국외 사례에서도 보강토 옹벽의 붕괴에 있어서 집중강우가 원인을 제공하는 것으로 나타났으며 본 옹벽의 경우 연결강도에 대한 설계가 제대로 이루어지지 않아 강우로 인해 발생한 침투수압에 블록/보강재 연결부가 충분한 저항을 하지 못하여 붕괴가 일어 난것으로 조사되었다. 본 논문에서는 강우와 보강토 옹벽의 거동의 상관관계를 분석 고찰하였다.

• Membrane and Water Treatment
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• 제10권3호
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• pp.201-206
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• 2019

In this study, we performed an electrowinning process for effective removal of metals (Cu and Ni) in solution and their recovery as solid forms. A complete removal of Cu and Ni (1,000 mg/L) was observed during four times recycling test, indicating that our electrowinning system can ensure the efficient metal removal with high stability and durability. In addition, we investigated effect of operation parameters (i.e., concentration of boric acid only for Ni, variation of pH, concentration of electrolyte ($H_2SO_4$), and cell voltage) on the efficiency of metal removal (Cu and Ni) during the electrowinning. The addition of boric acid significantly enhanced removal efficiency of Ni as the concentration of boric acid increased up to 10 g/L. Compared to negligible pH effect (pH 1, 2, and 4) on the Cu removal, we observed the increase in removal efficiency of Ni as the pH increased from 1 to 4. The electrolyte concentration did not significantly influence the removal of Cu and Ni in this study. We also obtained great removal rates of Cu and Ni at 2.5 V and 4.0 V, which were much faster than those at lower voltages. Finally, almost 99% of each Cu and Ni (1,000 mg/L) was selectively removed from the mixture of metals by adjusting pH and addition of boric acid after the completion of Cu removal. The findings in this study can provide a fundamental knowledge about effect of important parameters on the efficiency of metal recovery during the electrowinning.

• Geomechanics and Engineering
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• 제38권1호
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• pp.45-56
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• 2024

The weakening effect of water on rocks is one of the main factors inducing deformation and failure in rock engineering. To clarify this weakening effect, immersion tests and post-immersion triaxial compression tests were conducted on sandstone and mudstone. The results showed that the strength of water-immersed sandstone decreases with increasing immersion time, exhibiting an exponential relationship. Similarly, the strength of water-immersed mudstone decreases with increasing environmental humidity, also following an exponential relationship. Subsequently, a statistical damage model for water-weakened rocks was proposed, changes in elastic modulus to describe the weakening effect of water. The model effectively simulated the stress-strain relationships of water-affected sandstone and mudstone under compression. The R² values between the theoretical and experimental peak values ranged from 0.962 to 0.996, and the MAPE values fell between 3.589% and 9.166%, demonstrating the model's effectiveness and reliability. The damage process of water-saturated rocks corresponds to five stages: compaction stage - no damage, elastic stage - minor damage, crack development stage - rapid damage increase, post-peak residual stage - continuous damage increase, and sliding stage - damage completion. This study provides a foundational reference for researching the fracture characteristics of overlying strata during coal mining under complex hydrogeological conditions.

• Journal of Nutrition and Health
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• 제42권4호
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• pp.338-349
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• 2009

We aimed to evaluate the effect of nutrition education program on nutrition knowledge, dietary behavior, dietary intakes and anthropometric parameters in primary school children. Eighty five 4th grade children (boys = 43, girls = 42) were enrolled in the intervention program for 5 months. The subjects were asked to fill out a questionnaire about nutrition knowledge and dietary behavior two times, at the baseline and after completion of the program. Dietary intake information was collected from participants using a 3-day food record and their anthropometric parameters were measured. Upon completion of the intervention program, both nutrition knowledge and dietary behavior scores were significantly improved in all subjects. Energy intake was increased from 1,571.9 kcal to 1,734.1 kcal with significant improvements in nutrient density for protein, Ca, P, K, vitamin A and niacin. While subjects' height, weight, lean body mass and soft lean mass were significantly increased during the program, significant decreases were observed in the rohrer index, percent body fat, waist-hip ratio and body fat mass. The changes in nutrition knowledge scores were positively correlated with the changes in dietary behavior scores, micronutrient intakes and anthropometric parameters. These results indicate that enhancement of nutrition knowledge through well-planned long-term nutrition education program is effective not only for the improvement of dietary behaviors and dietary intakes but also for the positive changes in anthropometric parameters among primary school children.

• Journal of Yeungnam Medical Science
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• 제6권2호
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• pp.103-111
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• 1989

방사선 조사후 방광의 손상에 관한 실험에서 다음과 같은 결과를 얻었다. 1. 손상군, 회복군 모두에서 암수가 비슷한 변화를 보여 방사선에 의한 손상에서 암수의 차이는 없었다. 2. 점막의 변화는 40GY 조사군에서 50GY군 보다 빨리 회복됨이 관찰되었고 14주에서 대부분 소실되었다. 3. 혈관의 변화는 40GY, 50GY 모두에서 혈관확장증, 초자질화, 내피하층과 중간층의 섬유화 등이 관찰되었으며 혈관주변의 섬유화는 15주까지 관찰되었다. 결체조직과 균육층의 변화는 40GY, 50GY 모두에서 조사후 15주까지 지속됨을 볼 수 있었다. 마우스의 평균수명(460일-1000일)에 비해 본 연구의 추적 기간이 105일로서 충분히 길다고는 할 수 없으나 상기 여러 결과로 미루어 후기 반응의 감소 및 예방을 위해 세심한 조사 계획이 있어야 함을 시사하였다.

• 인지과학
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• 제7권3호
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• pp.115-134
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• 1996

외현기억은 의도적 인출을 의미하고 암묵기억은 비의도적 인출을 의미하며 다양한 변인하에서 외현기억과 암묵기억이 상이한 인출형태가 보이는 것을 기억해리현상이라 한다.본 연구에서는 기억해리현상을 설명하는 처리이론중 이중처리이론의 기본 가정을 수용하여 실험을 실시하였다.처리깊이에 따른 학습을 실시하면,지각 처리과제의 경우는 단어표상의 활성화가 이루어지며 이는 접속가능성의 증가로 나타나고,의미처리과제의 경우는 목표단어표상 및 관련단어의 표상이 활성화되고 이는 인출가능성의 증가로 나타난다.학습단계에서는 의미처리과제와 지각처리과제를 반복해서 제시하여 접속가능성과 인출가능성의 증가를 조작하였고,검사단계에서는 인출 지시문 종류에 따른 암묵 기억검사와 외현기억검사를 실시하였다.실험결과는 다음과같다. 지각처리과제의 반복은 암묵기억검사와 파지수준에는 영향을 주지만 외현기억검사의 파지수준에는 효과를 미치지 못했고,의미처리 과제의 반복은 암묵기억검사와 외현기억검사 파지 수준 모두에 영향을 미쳤다.실험결과를 종합하여 보면,처리깊이에 다른 학습 단어 반복제시의 기억 해리효과는 이중처리이론의 설명틀이 적절하다고 결론지울수 있다.

• 대한치과교정학회지
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• 제44권1호
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• pp.13-19
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• 2014

Objective: The aim of this study was to evaluate long-term changes in the pharyngeal airway dimensions after functional appliance treatment in adolescents with skeletal Class II malocclusions. Methods: Pharyngeal airway dimensions were compared between subjects with skeletal Class II malocclusions (n = 24; mean age: $11.6{\pm}1.29$ years) treated with a Class II bionator and age-matched control subjects with skeletal Class I occlusions (n = 24; mean age: $11.0{\pm}1.21$ years) using a series of lateral cephalograms obtained at the initial visit (T0), after treatment (T1), and at the completion of growth (T2). Results: The length of the nasopharyngeal region was similar between adolescents with skeletal Class I and Class II malocclusions at all time points, while the lengths of the upper and lower oropharyngeal regions and the pharyngeal airway areas were significantly smaller in the skeletal Class II adolescents before treatment when compared to the control adolescents (p < 0.05). However, following treatment with a functional appliance, the skeletal Class II adolescents had increased pharyngeal airway dimensions, which became similar to those of the control subjects. Conclusions: Functional appliance therapy can increase the pharyngeal airway dimensions in growing adolescents with skeletal Class II malocclusions, and this effect is maintained until the completion of growth.

• Plant Resources
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• 제5권3호
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• pp.206-209
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• 2002

This study was performed to investigate the effect of Mentha arvensis Herba extract on the treatment of chromaticity and colorfastness. Mentha arvensis Herba has been used as a Korean medicine. It is effective in headache and stress. It is also good as a aphtha and in treating cold. In the long history of Korea, dyeing has been applied for a means representing the grace of natural and inner esthetic consciousness of man. Vegetable dyes give us such great benefits, diversified color, but no pollution. And ramie fabric has distinctive features such as beautiful brilliance, elegance, and strong durability. So, it is regarded as a special product of Korea traditionally. These studies were carried out to treat with acetate iron, dichloride copper and alum with a mordant to ramie fabric. The ramie fabric was died with Mentha arvensis Herba extract. The results of experiment showed as follows: First, the chromophoric degree was the highest in acetate iron but not distinction in another mordants. Second, the light colorfastness was the highest in non treated and dichloride copper, but alum was the lowest. Third, the discoloration was alum and dichloride copper showed first grade in washing colorfastness. Abrasion colorfastness was not significant in this test. According the previous results, Mentha arvensis Herba has an efficiency in removing aphtha and in treating cold. So it is considered that Mentha arvensis Herba can be applied effectively to headache and stress.