• Bulletin of the Korean Chemical Society
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• 제12권3호
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• pp.315-322
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• 1991

In a recent $paper^1$ we reported equilibrium (EMD) and non-equilibrium (NEMD) molecular dynamics simulations of liquid argon using the Green-Kubo relations and NEMD algorithms to calculate the thermal transport coefficients-the self-diffusion coefficient, shear viscosity, and thermal conductivity. The overall agreement with experimental data is quite good. In this paper the same technique is applied to calculate the thermal transport coefficients of liquid water at 298.15 K and 1 atm using TIP4P model for the interaction between water molecules. The EMD results show difficulty to apply the Green-Kubo relations since the time-correlation functions of liquid water are oscillating and not decaying rapidly enough except the velocity auto-correlation function. The NEMD results are found to be within approximately ${\pm}$30-40% error bars, which makes it possible to apply the NEMD technique to other molecular liquids.

• Bulletin of the Korean Chemical Society
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• 제19권3호
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• pp.319-323
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• 1998

The phodissociation dynamics of t-butyl hydroperoxide at 280-285 nm has been investigated by measuring laser induced fluorescence spectra of the fragment OH. Measured fractions of the available energy distributed among the fragments are ft=0.56, fr(OH)=0.044, fint(t-BuO)=0.40, and negligible populations of OH are found in vibrationally excited states. By analyzing the Doppler profiles of the spectra of OH, the positive ν-J vector correlation has been obtained. From the measured ν-J correlation and A" propensity in the two Λ-doublets of OH, it is concluded that the dissociation takes place directly from the repulsive surface induced by the σ* ← n transition with the fragment OH rotating in the plane perpendicular to the dissociating O-O bond axis.

• Environmental Analysis Health and Toxicology
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• 제20권4호통권51호
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• pp.311-325
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• 2005

A chemical ranking and scoring system, CRS - Korea, has recently been developed and proposed to use to prioritize on a screening level the toxic chemicals for monitoring and risk assessment. As CRS-Korea requires rigorous assessments prior to its wide application, an assessment was conducted in this study by examining the contribution of individual parameter score to the final chemical score or ranking. The sensitivity of the system to the default values for various parameters of missing data was also tested. The chemical ranking/score was round to depend primarily on the score of a single parameter, i. e., the chemical release, while toxicity scores show little correlation with the priority Further analysis indicated that the dominating effect of the chemical release results from i) its multiplicative relationship with the other two exposure parameters (biodegradation and persistent) and ii) the fact that a maximum score of 10 was assigned to the chemical release parameter while 5 was assigned for all others. AE the fraction of the data that are missing exceeded $70\%$ for various toxicity parameters at compared to less than $10\%$ for exposure parameters, the sensitivity of the ranking to the default value was not significant (rank correlation coefficient = 0.98) for toxicity parameters. Bated on this assessment, an improved CRS system (CRS - Korea II) was proposed in which the impact of the chemical release was properly adjusted by changing the multiplicative relationship to additive one and the maximum score to 5. Chemical priority was derived for each of 16 provinces by using CRS-Korea II. The chemical priority was found to significantly vary among the provinces. It was concluded that not only the national chemical priority but the local chemical priority should be taken into account in setting the nationwide chemical monitoring and risk assessment strategy.

• 한국환경보건학회지
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• 제16권2호
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• pp.55-61
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• 1990

Laboratory methods commonly used today are biochemical oxygen demand, chemical oxygen demand, and total organic carbon. Establishment of constant relationships among the various measures of organic content depends primarily on the nature of the wastewater and its source. Of all the measures, the most difficult to correlate to the others is the BODs test, because of the problems associated with biological tests. The results were summarized as follwos, 1. For typical municipal wastes, however, the SBOD$_{5}$/SCOD$_{cr}$ ratio varies from 0.14 to 0.34(mean 0.21), SBOD$_{5}$/STOC ratio varies from 0.35 to 1.19(mean 0.69) 2. Correlation analysis between the SBOD$_{5}$ and SCOD$_{cr}$ gave good correlation coefficient r = 0.903 and the equation Y = 3.756X + 16,221 was obtained. 3. The correlation between the SBOD$_{5}$ and STOC was well presented with equation : Y = 1,070X + 7,637, and also correlation coefficient r = 0.821 4. The correlation between the SCOD$_{cr}$ and STOC was well presented with equation : Y = 0.256X +5.513 and also correlation coefficient r = 0.816. 5. Because of the rapidity with which the TOC test can be conducted, it is anticipated that more use will be made of these tests in the future.

• 한국태양에너지학회 논문집
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• 제32권1호
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• pp.8-14
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• 2012

Concerning about global warming due to emission of greenhouse effect gas like C02 and depletion of fossil fuels have been spreading. So the need for solar energy utilization is increased. It is essentially important to make efforts to reduce usage of fossil energy resources. In this study, we analyzed the correlation between climatic elements and the photovoltaic power generation. Cloud cover of the correlation coefficient was 0.93. The order of the correlation coefficient was average temperatures, hours of sunshine duration of sunshine and the humidity. To accurately analyze of the degree of correlation for the photovoltaic power generation, additional research about climatic elements that show a high correlation is needed.

• 한국산학기술학회논문지
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• 제13권3호
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• pp.1279-1283
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• 2012

탄소 주입 실리콘산화박막은 ICP-CVD에 의하여 dimethyldimethoxysilane를 이용하여 증착하였다. 화학적 변화와 광학적 변화에 대하여 관찰하기 위해서 FTIR, 스펙트라 포토미터 그리고 엘립소미터를 이용하였다. SiOC 박막의 결합구조는 증착과정에서 형성되고 열처리과정을 통하여 접착도가 증가된다. SiOC 박막은 알킬기와 수산기 사이의 화학적인 반응에 의해서 분극이 감소되고 비정질도는 증가된다. FTIR에서 950 cm-1 이하의 영역에서 알킬기와 수산기에 따른 분극의 특성에 따라서 FTIR 픽의 모양이 두가지로 다르게 나타났다. 분극이 가장 낮은 샘플에서 굴절률은 증가하였고 두께는 감소하는 특성을 관찰할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제26권1호
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• pp.115-118
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• 2005

The miniaturized NIR (Near-infrared) spectrometer has been utilized for the determination of water content (1-19% range) in ethanol that is the most popular organic solvent in pharmaceutical industries. It has many potential capabilities that can replace the conventional analyzers especially for the on-line measurement since it is compact, versatile and cost-effective. By using two dimensional (2D) correlation spectroscopy, it was preliminarily investigated to find any unforeseen spectral distortion among the spectra collected from the miniaturized spectrometer. The 2D study revealed that the spectral variation clearly followed the variation of water concentration without any spectral distortion or abnormality. PLS (Partial Least Squares) was employed to build the calibration model and the resulting prediction performance was acceptable and stable over several days. Even though the miniaturized NIR system was evaluated to fairly simple chemical matrix, the overall study demonstrates the sufficient feasibility for diverse practical and industrial applications.

• 대한안전경영과학회지
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• 제16권4호
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• pp.441-449
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• 2014

As people seek a healthy, wealthy, and quality life more than before, interests in mineral water are picking up and the consumption continues to increase accordingly. In an experiment to examine changes in the water quality after mineral water on the market was kept indoor and outdoor for four weeks, there seemed to be no problem in external appearance. Water kept in an outdoor storage contained more odor-savor than water kept in an indoor storage. Odor was not detected in 90% of the sample, and savor not in 80% of it. As for the mechanism of odor-savor generation, the elution of chemical substances from a container may be taken into consideration. In general, odor and savor have turned out to be in close correlation to each other. The average number of bacteria in the sample mineral water was $200{\pm}10CFU/mL$, and such factors as area of storage and ozone post-treatment did not cause significant effects on the reproduction of common microbes. Hence, it is thought that strict regulations on a production process and reduction of the period of circulation will contribute to customers consumption rates.

• Korean Chemical Engineering Research
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• 제46권1호
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• pp.88-93
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• 2008

지역규칙성 폴리3핵실티오펜과 용해성 플러렌 블렌드로 이루어진 벌크이종접합 고분자 태양전지를 제작하였다. 고분자 블렌드 필름에 대한 열처리 효과가 필름의 결정 구조와 자외선/가시광선 흡수스펙트럼에 주는 영향을 조사하였다. 그 후, 열처리에 의한 필름의 결정구조와 태양전지 효율의 상관관계를 연구하였다. 그 결과, $150^{\circ}C$에서 열처리한 필름이 분자간 상호작용 및 결정성측면에서 최적이었으며, 이 때, 고분자 태양전지의 에너지 전환 효율은 3.2 %이었다.

• 한국환경농학회지
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• 제42권2호
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• pp.152-158
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• 2023

This study was conducted to evaluate the effects on soil chemical properties and plant growth after applying soldier fly compost (SFC). Treatments were as follows. No fertilizer (NF), control, SFC1 (SFC 250 kg/10a), SFC2 (SFC 500 kg/10a) and SFC3 (SFC 1,000 kg/10a). As compared to control in the pot test, organic matter (OM) and exchangeable sodium (Ex-Na) of SFC3 treatment were increased, and growth and nutrient uptake of young radish were not significantly different. Correlation coefficient between soil chemical factors like total nitrogen (T-N), OM, and CEC and uptake of nitrogen (N) and phosphorus (P) was significantly positive (p≤0.05). Compared to control in the field test, electrical conductivity, T-N, OM, Av.-P₂O₅, and CEC was increased, and lettuce growth was not significantly different. Correlation coefficient between application amount of SFC and T-N, OM, and Av.-P₂O₅ was significant positively (p≤0.05). These results indicated that the application of SFC improved nutrient availability of soil by increasing OM and CEC.