• 폴리머
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• 제39권1호
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• pp.1-5
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• 2015

The effects of zeolite on the thermal stability of poly(vinyl chloride) (PVC) were investigated by the static thermal stability test, pyrolysis experiment and ultraviolet spectrum. The results showed that the porous zeolite could absorb hydrogen chloride (HCl), which suppressed the catalysis of HCl on thermal degradation of PVC, thus improved the thermal stability of PVC. The oxidizing acid which was loaded on zeolite had oxidated on the double bond that formed during the dehydrochlorination of PVC. This process could prohibit the growth of the conjugated polyene and improved the color of PVC. Hence, zeolite might be possible to come up with a high performance thermal stabilizer.

• 펄프종이기술
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• 제40권5호
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• pp.11-19
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• 2008

The paper established a new method for fast measurement and characterizing of sub-visible dirt of recycled paper which is too small to be seen with naked eye. This method provided a new way for the evaluation of recycled paper that is hard to be characterized by the conventional method. Two effective thresholding algorithms HA and SDA were compared and their applicable conditions were discussed. Results showed that the HA could be used for un-printed paper while SDA is suited for recycled papers. The gloss of paper samples was measured and the relation between gloss and sub-visible dirt was investigated. The significant effect of this method for characterizing and comparing paper was exhibited. The experiment results indicated that sub-visible dirt measuring method could be a complementariness of the conventional methods.

• Bulletin of the Korean Chemical Society
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• 제27권2호
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• pp.197-202
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• 2006

In the reaction A + B $^\rightarrow_\leftarrow$ C, where A and B are ionic reactants having opposite charges, a B molecule approaching an A will experience a switching of the interaction potential when the A molecule is captured by one of the other B molecules in the medium. In the reversible case, the former B molecule still has a chance to react with the A, so that one needs to take into account the switched interaction between the reactant B and the product C as well as that between the reactants to treat the kinetics accurately. It is shown that this kind of interaction potential switching affects the relaxation kinetics in an intriguing way as observed in a recent experiment on an excited-state proton transfer reaction.

• 대한화학회지
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• 제53권1호
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• pp.51-61
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• 2009

본 연구의 목적은 고등학교 ‘과학’과 ‘화학 II’의 ‘반응 속도의 측정’ 단원에서의 주된 학습 내용 을 분석하고, 학습 내용에 적절한 개선된 탐구 실험을 제시하는 것이다. 학습 내용의 분석을 위해 고등학 교 ‘과학’ 11종, ‘화학 II’ 8종의 교과서와 교사용 지도서 11종을 분석하고, 교사들의 인식을 조사하였다. 대부분의 교과서와 교사들이 ‘시간에 따라 반응 속도가 점점 느려진다’는 개념을 학습 내용으로 제시 또 는 인식하고 있으나, 교과서에 제시된 탐구 활동의 내용은 ‘시간에 따른 반응 속도의 감소’를 설명하기 에 부적절한 경우가 있었다. 학습 내용에 적절한 탐구 활동을 제안하기 위해 개선된 조건에서 염산과 마 그네슘의 반응 실험을 실시하였고, 얻어진 실험 결과를 이론적으로 예측한 결과와 비교함으로써 ‘시간 에 따른 반응 속도의 감소’를 설명하기에 타당함을 알 수 있었다. 본 연구에서 개선된 탐구 활동은 교과 서의 화학 반응 속도에 대한 개념을 보다 정확히 기술하는데 도움이 될 수 있을 것으로 기대된다.

• 대한화학회지
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• 제55권4호
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• pp.703-714
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• 2011

이 연구에서는 안산시의 지리적 특성을 반영한 고등학교 화학 I 단원의 STS 모듈을 개발하여 교과 수업에 적용한 후, 과학에 관련된 태도에 미치는 영향 및 STS 수업에 대한 선호도를 분석하였다. 연구 대상은 경기도 안산시에 소재한 K고등학교 2학년 2개 반 71명을 실험 집단으로, 2개 반 78명을 통제 집단으로 하였으며, 연구는 동일 집단 사전 사후설계 방식으로 진행되었다. 안산 지역 특성을 반영한 STS 모듈은 고등학교 화학 I 단원과 관련하여 물 공기 에너지를 주제로 4차시를 개발하여 적용하였으며, 수업 전 후 과학에 관한 태도와 STS 수업에 대한 선호도를 조사 분석하였다. 과학에 관한 태도 검사에서 STS 모듈을 적용한 실험 집단이 교과서 중심의 수업을 한 통제 집단에 비해 통계적으로 유의미한 향상 효과가 나타났으며, STS 수업에 대한 선호도 조사 결과에서도 학생들은 STS 프로그램에 대해 매우 긍정적이었으며, 사회와의 관련성 영역에서 보다 큰 선호도를 나타내었다. 이러한 연구 결과는 과학 기술 사회의 상호관련성에 관한 과학 수업의 효율적인 적용을 위해서는 학생들이 보다 주체적으로 참여할 수 있는 지역적 특성을 반영한 STS 모듈을 개발하여 적용할 필요가 있음을 시사한다.

• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.99-105
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• 1996

Effects of conjugated linoleic acid(CLA), known as an effective anticarcinogen in several aminal models, on the egg production and egg weight of laying hens, and the weight gains of broilers were investigated. CLA was synthesized from corn oil by the alkaline isomerization method and purified by the low-temperature precipitation method. Diets for laying hens and for broilers were synthesized to meet the specification of their NRC standard rationals. Two separated experiments(Experiment I and II) were conducted for laying hens. in experiment I, 45 hens(300 days of age) were divided into 15 hens per treatment group; each hen was housed in wired cage located in a temperature and humidity-controlled house and adopted to the control diet. One week later, each group was subjected to one the four treatment groups for 5 weeks : control, 1.0% CLA, 2.5% CLA and 5.0% CLA diets. Diet and water were ad libitum. The condition of experiment II was the same as that of experiment I except for the addition of 5% corn oil diet and the extension of feeding period to 7 weeks. Egg production, egg weight and feed intake were recorded every week. Forty-five broilers(10day of age) were adopted to the control diet for a week and then switched to the treatment diets for 5 weeks : control, 1.0% CLA, 2.5% CLA, 5% CLA and 5% corn oil, Body weight and feed intake of broilers were measured every week. Diets supplemented with various amounts of CLA enhanced the egg production and increased the egg weight regardless laying hen's age(150 days or 300 days) as compared to control diet. The most effective diet for the egg production and egg weight of young hens(150 days of age) was found to be 1.0% CLA diet, but relatively higher CLA diet(2.5% CLA) was required for old hens (300 day of age) to obtain similar results as seen in younger hens. All hens treated with CLA ate greater amount of feed than control hens. Broilers treated with various amount of CLA ate less feed as compared to control ones, but the body weight gain was greater than the control broilers. These results indicate that CLA enhanced the egg production and agg weight of laying hens, and increased the body weight gain of broilers with less diet consumption.

• 한국환경농학회지
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• 제33권3호
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• pp.164-168
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• 2014

BACKGROUND: Increase in application of liquid pig manure(LPM) in agriculture as nutritional source has become a social issue due to its influence on water quality. Also, proper application methods have not been developed with respect to indigenous properties of LPM and soil physical properties. Therefore, we conducted this experiment to observe the infiltration characteristics and distribution of dissolved organic compounds of LPM in soils having different soil textures. METHODS AND RESULTS: To do this experiment, we collected three different soils and LPM. We analyzed the physical and chemical properties of both soils and LPM to determine the dilution ratios of LPM. The LPM diluted to 4 different ratios with distilled water was applied to the top of soil column. Infiltration rates were observed by time and depth until the amount of effluent collected from the bottom of the soil columns were stabilized while maintaining the hydraulic head 3 cm above the soil column. The results showed that infiltration rates increased with increasing dilution ratios in the order of sandy, loamy sand, and sandy loam. The time required to reach steady state was increased with decreasing sand contents clay. CONCLUSION: The size and amount of the dissolved organic compounds in LPM that can determine the efficiency as fertilizer and environmental problems as nonpoint pollution source in water quality have not been investigated with respect to behavior and transport of them in soil. Therefore, it requires further research how we can properly apply LPM as valuable fertilizer substitute for inorganic fertilizers.

• 분석과학
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• 제20권4호
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• pp.289-295
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• 2007

사각파형 벗김 전압 전류법과 순환 전압 전류법에서 적외선 광 다이오드의 간단한 전자 회로를 사용한 철의 정량을 연구하였다. 기존에 사용되는 작업 전극과 최적 분석 조건을 비교하였으며, 순환 전압 전류법의 결과는 보다 간단하며 정밀하였으며, 최적 조건에서 농도 범위는 0.1-0.8과 0.85-6.0 mg/L 이었다, 0.4 mg/L의 철 농도에서 15번 반복 측정한 상대 표준편차는 0.09%였으며, 최소 분석 검출 한계는 $80{\pm}0.6{\mu}g/L$ 였다, 이결과는 폐수중의 철 정량에 응용하였다.

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2011년도 추계학술발표회
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• pp.154-155
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• 2011

• 한국임상수의학회:학술대회논문집
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• 한국임상수의학회 2007년도 춘계학술대회
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• pp.170-170
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• 2007