• Journal of the Korean Chemical Society
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• v.18 no.5
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• pp.307-319
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• 1974

The accuracy of the uniform WKB solution for a two-turning point problem is examined in comparison with the corresponding numerical solution. It is found that the uniform WKB solution is extremely accurate. Various Franck-Condon factors for a model system are calculated as an example of applications of such approximate wavefunction. The accuracy of the factors thus calculated is very good. By using the uniform WKB wavefunctions, we have examined the asymptotic limit of the Frank-Condon factors and derived the condition for the frequencies of the transitions, $E'_{n'J'}-U'_{eff}(r_s)=E"_{n"J"}-U"_{eff}(r_s),$, which was obtained by Mulliken using physical arguments.

• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1775-1779
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• 2006

A liquid chromatographic chiral stationary phase (CSP) based on (+)-(18-crown-6)-2,3,11,12-tetracarboxilic acid without extra free aminopropyl groups on silica surface has been demonstrated to be quite effective for the resolution of various $\beta$-amino acids. The retention factors ($k_1$) for the resolution of $\beta$-amino acids on the CSP were quite large and the large retention factors might be quite attractive along with the reasonable separation factors ($\alpha$) for preparative scale enantioselective chromatography. The large retention factors on the CSP were found to be reduced effectively by adding ammonium ion to mobile phase without sacrificing the chiral recognition efficiency of the CSP. Consequently, the CSP is also quite applicable for use in analytical enantioselective chromatography.

• Journal of the Korean Society of Tobacco Science
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• v.26 no.2 s.52
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• pp.85-92
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• 2004

This study was conducted to investigate the relationship between weather factors during the growing season and chemical components of burley tobacco. Chemical components used in this study was from 'Farm Leaf Tobacco Test' conducted at KT&G Central Research Institute from 1987 through 2002. Data of weather factors during growing season(April to July) were collected in 6 districts measured at Korea Meteorological Adminstration(KMA). Total nitrogen content was increased from 1987 through 2002. Year to year variation of rainfall was the largest, followed by that of sunshine hour. Month to month variation of rainfall also was the largest, followed by that of mean daily air temperature. A negative correlation was found between rainfall and sunshine hour. Relative humidity(R.H.) was correlated positively with rainfall, whereas negatively with sunshine hour. The negative correlations were found between nicotine content and rainfall(in June, May$\~$June, June$\~$July, May$\~$July and average), and R.H.(in June, May$\~$June, June$\~$July, May$\~$July and average), respectively. The negative correlations were found between crude ash content and rainfall(in June and May$\~$June), and R.H.(in June, May$\~$June, June$\~$July and May$\~$July), respectively. Ether extraction content was correlated positively with mean daily air temperature(in July, June $\~$July and May$\~$July) and with sunshine hour(in July, June$\~$July and May$\~$July), but negatively with rainfall(average) and with R.H.(in April, July, June$\~$July, April$\~$June, May­July and average), respectively. Chloride content was correlated positively with sunshine hour(in May, April$\~$May, May$\~$June, April$\~$June, May$\~$July and average), but negatively with rainfall(in June, May$\~$June, June$\~$July, April$\~$June, May$\~$July and average).

• Composites Research
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• v.24 no.1
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• pp.31-36
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• 2011

Adhesive shear strengths of the established adhesives and the alternative adhesives were evaluated and their chemical structures were analyzed in order to investigate the possibility of replacing the established adhesives with the alternative adhesives applicable to the seeker for the guided missiles. Two types of the adhesives such as the structural adhesives and the sealant adhesives were considered. Those adhesives were exposed to the combined environmental factors consisting of temperature, moisture and ultraviolet over 1000 hours. Adhesive shear test was conducted to evaluate adhesive shear strengths and ATR FT-IR was utilized to investigate chemical structures. According to the results, the adhesive shear strengths of the alternative adhesives revealed higher than those of the established adhesives. Also the alternative adhesives were more stable to the combined environmental condition than the established adhesives. Therefore, it is found that the established adhesives were able to be replaced by the alternative adhesives.

• 한국생태학회:학술대회논문집
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• 1999.05a
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• pp.65-65
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• 1999

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.49-52
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• 2009

Single-drop microextraction (SDME) is an extraction methodology where the drop plays an essential role as extracts. It was evaluated for the GC-MS determination of nerve agents, one class of the chemical warfare agents (CWAs). Since these nerve agents are highly toxic, it is important to detect the nerve agents in the environmental samples. Several affecting factors including extraction solvents, stirring rate, extraction time, and amounts of salt were optimized. The limit of detections (LODs) were 0.1 - 10 ng/mL and the relative standard deviations (RSDs%, n=5) were in the range of 6.3% to 9.0% for four nerve agents. Without pretreatment of the environmental samples, 5-103 fold enrichments and 48-100% recovery were accomplished. These results demonstrated the feasibility of this method for on-site and off-site analysis of water sample collected from suspicious CWAs site.

• Korean Journal Plant Pathology
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• v.13 no.4
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• pp.244-247
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• 1997

The experiment was conducted to obtain a basic information on the enviroumental factors favoring the disease development and chemical control of clubroot in chinese cabbage. The inoculation by insertion of infested soil was the most effective for the disease development as compared to the other inoculation methods such as pouring the spore suspension into soil and dipping roots into the spore suspension. On the environmental factors favoring the clubroot development, optimum slil pH and soil temperature were pH 5-6 and $20{\sim}30^{\circ}C$, respectvely. The combination of soil treatment and seed coating treatment was more effective than each single treatment in the chemical control of clubroot by 0.5% of fluazinam dust.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.285-293
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• 2015

Objectives: This study was conducted in order to ascertain the important factors for SMEs in managing the risks of chemicals and to suggest a government role in strengthening the responsibility of small and medium enterprises(SMEs) as employers. Methods: About 100 enterprises were surveyed in Incheon. A questionnaire for employers and walk-through surveys by occupational hygienists were performed at each enterprise. Results: The results showed that most employers thought chemicals were not hazardous but chemical management was needed. When employers determine how to manage chemicals, they rely heavily on personal experience and rather less on information from the government or experts. However, if employers think the chemicals are hazardous, they do more to manage the chemicals. Conclusions: When employers think chemicals are hazardous, risk assessment would be an effective tool to control chemical hazards in SMEs. Employers' position on chemical hazards is very important. Since the government is the initiator, it is the government who develops messages for SMEs, such as "Chemicals are hazardous and management can reduce the risk of chemicals." Governmental messages can play an invaluable role in strengthening the responsibility of SME employers to manage chemical hazards.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.150-156
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• 2018

As the types and usage of chemical increase, modern countries should protect their health and environment from the risk of hazardous chemical. Chemical accidents not only affect humans but also cause huge losses to the environment. Moreover, since its effects do not end in a short period of time, it is necessary to identify the extent of the damage and establish a prevention and response system in advance. In 2015, the Chemical Substances Management Act provided a system for assessing the impact on the people and the environment around the workplace. However, it is difficult to quantitatively evaluate the impact on environmental factors such as vegetation and aquatic, with the current hazard assessment methods. The purpose of this study is to analyze the quantitative risk of environmental receptors. This study improved the existing risk assessment formula by using the environmental vulnerability index and established the end point concentration criterion which can estimate the damage range to environmental media. To verify the results of the study, a virtual accident scenario was selected and a case study was conducted. As a result, the extent of impact on the environmental medium can be calculated, and the degree of environmental risk of the zone can be quantified through the risk analysis considering the environmental vulnerability. This study is expected to increase the reliability of the reliability of the existing risk anaylsis method beacause it is a risk analysis method that can be applied when the environmental factors are absolutely necessary and when the residents and environment are complex.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.2
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• pp.89-99
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• 1984

Engineering properties of soils is studied by permeating injection of water-glass chemical grout by use of a large sized grouting equipment of 1.5 shot system. Furthermore, the effectiveness of chemical groutinig by taking water-glass chemical grout combined with portland-cement for the purpose of improving the soil strength is confirmed. Relationships between main factors which cause the effectiveness of chemical grouting are described, and the factors are velocity and temperature of flowing water; grain size distribution and density of soils; density, viscosity, gel time and volume of grouts; injection pressure and grouting process. Improvement of the effectiveness of chemical grouting in flowing water by preventing the dilution and flowing down of grouts is investigated. Moreover, local shear failures and upheaval phenomena of ground are also investigated by field measurement.