• Toxicological Research
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• 제24권3호
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• pp.207-212
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• 2008

Pesticide residues play several key roles as environmental and food pollutants and it is crucial to develop a method for the rapid determination of pesticide residues in environments. In this study, a simple, effective, and sensitive method has been developed for the quantitative analysis of methoxyfenozide in water and soil when kept under laboratory conditions. The content of methoxyfenozide in water and soil was analyzed by first purifying the compound through liquid-liquid extraction and partitioning followed by florisil gel filtration. Upon the completion of the purification step the residual levels were monitored through high performance liquid chromatography(HPLC) using a UV absorbance detector. The average recoveries of methoxyfenozide from three replicates spiked at two different concentrations and were ranged from 83.5% to 110.3% and from 98.1% to 102.8% in water and soil, respectively. The limits of detection(LODs) and limits of quantitation(LOQs) were 0.004 vs. 0.012 ppm and 0.008 vs. 0.024 ppm, respectively. The method was successfully applied to evaluate the behavioral fate of a 21% wettable powder(WP) methoxyfenozide throughout the course of 14 days. A first-order model was found to accurately fit the dissipation of methoxyfenozide in water with and a $DT_{50}$ value of 3.03 days was calculated from the fit. This result indicates that methoxyfenozide dissipates rapidly and does not accumulate in water.

• Journal of Applied Biological Chemistry
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• 제54권3호
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• pp.225-229
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• 2011

본 연구는 호수바닥에 있는 인의 용출 메카니즘을 규명하고자 유기물이 없는 시료(흙)에 호기성과 혐기성 실험하여 인 용출을 연구하였다. T-P의 증가 대부분은 $PO_4-P$ 증가에서 기인됐고, 약 pH 4-7 정도에서 $PO_4-P$는 호기, 혐기 그리고 pH 변화에도 점진적인 증가를 나타낸 원인은 한번 용출된 $PO_4-P$는 탁도에 흡착되지 않고 용존 하면서 계속해 탁도물질에서 $PO_4-P$를 용출하기 때문이다. T-P, 탁도, pH 그리고 DO의 유사한 변화 양상은 시료의 포도당 분해 시 DO 감소로 혐기화되면 유기산이 생성되어 pH가 감소하고, 탁도물질은 pH 감소로 침전이 촉진되며, 침전된 탁도물질은 미생물의 분해작용이 없어도 인이 용출된다. 이 메카니즘은 호수 바닥으로부터 물로 공급되는 인을 이해할 때 대단히 중요하다.

• 농업과학연구
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• 제47권2호
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• pp.375-380
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• 2020

The high intrinsic water content and salinity of food waste prevent a smooth composting process and consequently cause social, economic and environmental problems. In this study, we investigated the distribution of the water content and salinity in food wastes to obtain useful primary data to ensure adequate and quality recycling. A total of 300 food waste (FW) samples were collected from residential apartments (home generated FW), a wide range of restaurants, i.e., restaurant generated FW that included Korean, Chinese, Japanese and western FWs, and several places that included food waste processing facilities (dehydrated FW cakes). The collected food wastes were oven dried for 48 hours at 80℃ after which the water and salinity contents were analyzed. The results show that the average water content of the FWs was 72.45 ± 10.51%, and the average salinity content was 2.03 ± 0.57%. Furthermore, the salinity of the collected FWs was characterized by where the FW was generated. By location, the salinity concentration of home generated FW was 2.30% while western food had the lowest salinity concentration of 1.18%. However, dehydrated cakes had the highest salinity concentration of 2.84%. Especially, the distribution of the salinity content in food wastes can form the basis for improving the compost quality in food waste recycling.

• 유통과학연구
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• 제20권8호
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• pp.81-91
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• 2022

Purpose: The work aimed to integrate and distribute the knowledge of marketing and chemistry for product development, in which individual packaging from water hyacinth was ideal. Research design, data, and methodology: A customer perception was surveyed to guide the preparation process, and eco-packaging preparation followed the perception study. The satisfaction with the packaging using the 4Ps was determined. Results: 159 samples participated in the survey to establish their perceptions. They perceived that eco-packaging was a friendly environment with a score of 4.47. The uses of chemicals and water were less. The design for other functions than a normal function of packaging was preferred. The pulping was done using 3.0 M NaOH. The natural additives of carboxymethyl cellulose (defibering) and corn starch (adhesive) were desired. The paper was characterized according to The National Standard of Kraft paper and was equivalent to the liner board. The prototype of packaging was fabricated as individual packaging. The marketing mix was used to survey 200 samples. The satisfaction with the product was the maximum at 4.53, while the minimum was on price. The online channel was preferred to access the product. Conclusions: Water hyacinth could be added value as eco-packaging that the qualities of pulp were equal to the Kraft paper. Individual packaging from water hyacinth was satisfied.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.142.1-142.1
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• 2016

We present bulk diffusion rates of hydroxide ions in amorphous solid water (ASW) at 135 ~ 160 K. Previous researches showed that the diffusion mechanism of hydroxide is different from one of hydronium ions, and this implies that they have different diffusion rates. In ultra-high vacuum (UHV) chamber, low-energy scattering (LES) was used to measure ion population and temperature-programmed desorption (TPD) was conducted for measuring ASW thicknesses. To determine the diffusion rates, a simple model for $H_2O/NaOH/H_2O$ sandwich films was developed using Fick's second law. The measured surface population of hydroxide ions as a function of time was well fitted to the model, and the rates were well agreed to an Arrhenius equation.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.798-804
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• 2014

We present calculations for diglycine - $(H_2O)_n$ (n = 0-3) to examine the effects of microsolvating water on the relative stability of the zwitterionic vs. canonical forms of the dipeptide. We calculate the structures, energies and Gibbs free energies of the conformers at wB97XD/6-311++G** and MP2/aug-cc-pvdz levels of theory level of theory. We predict that microsolvation by up to three water molecules does not give thermodynamic stability of the zwitterion relative to the canonical forms. Our calculations also suggest that zwitterionic diglycine - $(H_2O)_3$ is not stable kinetically in low temperature gas phase environment.

• Macromolecular Research
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• 제9권5호
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• pp.253-258
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• 2001

Crosslinked poly(ethylene glycol)s (PEGs) were prepared by ultraviolet irradiation of low molar mass, liquid PEGs in the presence of benzophenone (BP) as a photoinitiator. The networks obtained have been characterized by DSC, IR, and contact angle measurements, and their water absorption and equilibrium swelling have been examined. The percent of gel formed and degree of swelling of the networks in water were dependent on the amount of BP in the reaction mixture, irradiation time and molar mass of PEG. Gel fraction yield exceeded 84%, and equilibrium swelling in water varied from 49 to 244%.

• Journal of Photoscience
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• 제5권1호
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• pp.27-31
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• 1998

An artificial photolysis system of water or aqueous alcohol is studied. Upon irradiation of agarose gel system containing colloidal CdS or TiO$_2$ particles with Rh catalyst, hydrogen and oxygen are produced from water. When an alcohol is used as an electron donor in the agarose system, hydrogen and oxidized form of alcohol, the corresponding an aldehyde, is produced. The photolysis mechanism of water or alcohol in the agarose system is proposed.

• Bulletin of the Korean Chemical Society
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• 제25권8호
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• pp.1161-1164
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• 2004

Calculations are presented for phenol ?acetonitrile - $(water)_n$ (n = 1-3) clusters. We examine the nature of interactions in the mixed clusters by calculating and comparing the structures, relative energies and harmonic frequencies of isomers with different type of hydrogen bonding. The conformers exhibit quite different patterns in the shifts of the CN and OH stretching frequencies, depending on the type of hydrogen bonding. Cyclic hydrogen bonding among the water molecule(s), acetonitrile and phenolic OH proves very important in determining the relative stability. It is also shown that acetonitrile tends to bind to the OH group of phenol in low energy conformers.

• Journal of Ginseng Research
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• 제14권1호
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• pp.30-35
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• 1990

The photooxidation of human erythrocyte ghosts has been studied and the effects of ginseng water extract on it have been investigated. In the presence of photosensitizer, rose bengal, human erythrocyte ghosts have caused photooxidation by lO2 and produced lip)id hydroperoxides. Ginseng water extract and d-${\alpha}$-tocofherol have inhibited photooxidation, ,whereas ascorbic acid has developed in low concentrations but inhibited in high concentrations. On the other hand, amounts of lipid hydroperoxide produced by photooxidation were decreased by addition of catalase after irradiation and according to sequential addition of ginseng water extract into it, the formation of lipid hydrolleroxide was decreased simultaneously.