• Korean Journal of Environmental Agriculture
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• v.11 no.2
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• pp.146-154
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• 1992

DDVP, malathion and diazinon ECs which differ in chemical compositions and moisture contents were formulated with nine emulsifiers, three solvents(xylene, cyclohexanone and DMF) and epichlorohydrin. For the studies of decomposition characteristics, these technicals and ECs were subjected to the test under elevated temperature at $54^{\circ}C$ for 15 days and $38^{\circ}C$ for 90 days respectively. DDVP technical was rapidly decomposed in early stage of thermoaccelerated test at $54^{\circ}C$, but the decomposition rate slowed down with time. As for malathion and diazinon technicals, the longer they were incubated, the more decomposed. The decomposed AI in ECs increased with solvent polarity. The increment of moisture content in ECs accelerated the decomposition of AI, and that was remarkable especially in diazinon ECs. Addition of emulsifiers increased the moisture content to be accelerated the decomposition of AI, but the decomposition of AI was more affected by the kind of emulsifier than by the moisture content of emulsifier, Stabilizing effect by epichlorohydrin was distingished in malathion and diazinon ECs, but there was no effect in other solvent-based formulation except xylene.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.140-140
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• 2018

• Journal of Food Hygiene and Safety
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• v.20 no.4
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• pp.225-231
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• 2005

This study was carried out to observe the stability of riboflavin in dietary supplements. Dietary supplements were in the type of tablet, powder, capsule and liquid. Various factors on the stability of riboflavin such as effect of light, storage temperature and time were examined using HPLC method. Samples were exposed to various temperatures (-9, 4, $30^{\circ}C$) and light at room temperature far 9 months. As well as storage period became longer, reduction rate constant of riboflavin increased. Riboflavin reduction rate constants were higher during storage with light than without light. And there was a significant difference of reduction rate constants in types of dietary supplement. In other words, riboflavin in tablet types was significantly more stable than the others, and liquid type was the most unstable. Therefore, type, light, and packing container of dietary supplements containing riboflavin would be considered in order to establish their appropriate shelf lives. In consideration with riboflavin decrease in dietary supplements, riboflavin would be appropriate for the nutritional labelling guide when predicting them at the end of shelf lives.

• Journal of the Korean Ceramic Society
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• v.37 no.12
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• pp.1140-1145
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• 2000

Ni의 함량이 서로 다른 Ni-YSZ 복합체를 100$0^{\circ}C$ 환원 분위기 하에서 열처리하며 시간에 따른 미세구조의 변화를 관찰하였다. Quantitative microscopy 이론을 응용한 화상분석 결과 Ni-YSZ 복합체의 미세구조는 열처리시 나타나는 Ni상의 미세구조 변화에 가장 큰 영향을 받고 있었다. 특히 Ni의 양이 많은 조성에서는 Ni 상간의 접촉이 많아 고상반응에 의한 미세구조의 변화가 심하였는데 이로 인해 복합체 미세구조의 안정화가 느리게 진행되었다. Ni-YSZ 복합체의 전기 전도도 역시 Ni상의 미세구조 변화에 큰 영향을 받았는데 복합체 전체 미세구조의 경시변화와는 달리 Ni상의 많은 조성보다는 Ni상의 percolation이 일어나는 조성 부근에서 더 큰 영향을 받았다. 이로 인해 Ni-YSZ의 전기 전도도는 Ni의 percolation threshold 부근 조성에서 안정화되는데 더 많은 시간을 요하였다.

• Journal of the Korean Wood Science and Technology
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• v.39 no.6
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• pp.505-511
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• 2011

In this study, it is carried out to analysis of the bolt pretension of the stress-laminated timber. Bolt pretension of stress-laminated timber was decreased by time. The loss of force is caused by moisture content, shrinkage of wood. After re-stressing the stress-laminated timber, the rate of force decrement was slowed significantly. To use of stress-laminated timber for the service, it is necessary to make an accurate estimate of force. It is clear that is different between actual value and predicted value changes by existing model for bolt pretension of stress-laminated timber. Accordingly, considering the time and the external environment, the development of prediction model is needed.

• Cement Symposium
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• no.29
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• pp.231-237
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• 2002

• Analytical Science and Technology
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• v.23 no.1
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• pp.24-35
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• 2010

To learn more about the calibration properties of reduced sulfur compounds (RSCs) by the combination of gas chromatography(GC)-pulsed flame photometric detector (PFPD) and thermal desorption method, a series of calibration experiments were conducted on the basis of both internal and external calibration approaches. For these experiments, gaseous standards of 4 RSCs ($H_2S$, $CH_3SH$, DMS, and DMDS) were prepared at two different concentration levels of both low (10, 20, 50,and 100 ppb) and high ranges (100, 200, 500, and 1000 ppb) along with $CS_2$ as an internal standard. First, the external calibration results were compared between fixed standard volume (FSV) and fixed standard concentration (FSC) method. Secondly, FSV-based calibration results were compared between external and internal calibration results. As FSV method suffers from sensitivity variations less significantly than FSC, the former is recommended to maintain the consistency in GC-TD sensitivity for RSC analysis. In addition, when the calibration data were examined in terms of RSE between external and internal calibration data, the results were not consistent enough to show improvements in internal method. Hence, diverse efforts are desirable to optimize the reproducibility in terms of GC-TD sensitivity for RSC analysis.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1998.04a
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• pp.208-209
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• 1998

• Cement Symposium
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• no.23
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• pp.133-139
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• 1995

• Cement Symposium
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• no.25
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• pp.110-116
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• 1997