• 상하수도학회지
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• 제10권4호
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• pp.119-126
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• 1996

Influence factors and efficiency characteristics for treatment of wastewater containing phenol were studied with using Pseudomonas sp. B3. It took 130 hours to remove phenol, when only activated sludge of terminal disposal palnt of sewage was innoculated in batch culture, but it was required just 36 hours, when bacteria degrading phenol and activated sludge were simultaneously innoculated. If only phenol an carbon source was used, it necessary 36 hours for biodegradation of phenol, while glucose was added to medium, it took 73 hours. It was revealed as excellent effluent and SVI, when the F/M ratio, COD and phenol concentration were 53mg/l and 1.2mg/l, respectively, and optimum F/M ratio was revealed 0.31. The reactor were seriously shocked as reducing hydraulic retention time at constant phenol concentration more than increasing phenol concentration at constant hydraulic retention time, when volumetric loading rate was increased to $0.8kg\;phenol/m^3{\codt}d$ from $1.6kg\;phenol/m^3{\codt}d$. And also the effluent phenol concentration was 34mg/l after starting 12 hours of shocking and reactor was recovered as steady state after 65 hours of changing in the former test. Although the effluent phenol concentration was maximum value with 12mg/l after starting 20 hours of shocking and reactor was recovered as steady state after 54 hours of changing in the later test.

• 공업화학
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• 제19권4호
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• pp.366-369
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• 2008

입자상 알루미늄 충전복극조의 성능을 파악할 목적으로 실험은 회분식과 연속식으로 진행하였다. 입자상 알루미늄 충전복극조를 이용하여 T-P 농도 10 mg/L인 인산염 함유 용액을 6 V에서 3 h 회분식으로 전해처리 한 결과 T-P의 제거율은 88% 이었다. 입자상 알루미늄 충전복극조를 이용하여 T-P 농도 10 mg/L인 인산염 함유 용액을 6 V에서 HRT를 3 h으로 하여 연속식으로 전해처리 한 결과 T-P의 농도는 2 mg/L이었다. HRT 3 h으로 고정하여 전해처리 할 경우 120 h 처리 후 파과점을 관찰할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제24권9호
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• pp.1339-1344
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• 2003

Flow field-flow fractionation (FlFFF) is a technology to separate the molecules by size in an open channel. Molecules with different size have different diffusivities and are located vertically in different positions when passing through an open channel. In this study, hollow fiber membranes instead of conventional rectangular channels have been used as materials for the open channel and this change would decrease the cost of manufacturing. FlFFF is a useful technique to characterize the biopolymeric materials. Retention time, diffusion coefficients and Stokes radius of analysis can be calculated from the related simple equations. Hollow-fiber flow field-flow fractionation (HF-FlFFF) has been used for the characterization and separation of protein mixture in a phosphate buffer solution and has demonstrated the potential to be developed into a disposable FlFFF channel. The important indexes for the analytical separation are selectivity, resolution and plate height. The optimized separation condition for protein mixture of Ovalbumin, Alcohol dehydrogenase, Apoferritin and Thyroglobulin is ${\dot V}_{out}/{\dot V}_{rad}=0.65/0.85\;mL/min$.

• 대한가정학회지
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• 제46권10호
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• pp.1-9
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• 2008

The purpose of this study was to increase uv-cut ability of cotton, ramie, and rayon fabrics dyed with safflower red colorants. For this purpose, samples treated with uv-cut agent and tannic acid were compared with the untreated samples after ultraviolet(uv)-light exposure in terms of K/S value, color changes(${\Delta}E$), SEM, and tensile strength retention. K/S value rapidly decreased with increasing exposure time, but K/S value of the samples treated with both uv-cut agent and tannic acid decreased less than that of untreated samples. As increasing exposure time, $L^*$ and $b^*$ increased, $a^*$ decreased, and so ${\Delta}E$ increased, indicating less red character and more yellow character in color. This leads to change hue, value and chroma value. But color change of samples treated with both uv-cut agent and tannic acid was less than that of untreated samples. SEM pictures showed a severe degradation by uv exposure in all samples. Tensile strength slowly decreased for 21 days. And after this point, the decreased proceeded more rapidly. Tensile strength retention of the samples treated with uv-cut agent and tannic acid was higher than that of untreated samples.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1819-1824
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• 2006

The general objective of the present study was to investigate the potential application of the UV spectroscopic method for determination of the polymeric additives present in papermaking fibrous stock solutions. The study also intended to establish the surface-chemical retention model associated with the adsorption kinetics of additives on fiber surfaces. Polyamide epichlorohydrin (PAE) wet strength resin and imidazolinium quaternary (IZQ) softening agents were selected to evaluate the analytical method. Concentrations of PAE and IZQ in solution were proportional to the UV absorption at 314 and 400 nm, respectively. The time-dependent behavior of polymeric additives obeyed a mono-molecular layer adsorption as characterized in Langmuir-type expression. The kinetic modeling for polymeric adsorption on fiber surfaces was based on a concept that polymeric adsorption on fiber surfaces has two distinguishable stages including initial dynamic adsorption phase and the final near-equilibrium state. The simulation model predicted not only the real-time additive adsorption behavior for polymeric additives at high accuracy once the kinetic parameters were determined, but showed a good agreement with the experimental data. The spectroscopic method examined on the PAE and IZQ adsorption study could potentially be considered as an effective tool for the wet-end retention control as applied to the paper industry.

• 한국식품과학회지
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• 제17권5호
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• pp.406-408
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• 1985

본 연구에서는 현미취반시 생성되는 고휘발성 향기성분중 고미취의 주성분인 n-hexanal의 가스크로마토그래피에 의한 분리및 정량방법을 개선하였다. 개발된 가스크로마토그래피의 운전조건하에서 n-hexanal의 분리를 시도한 결과, n-hexanal은 다른 고휘발성 향기성분으로부터 완전히 분리가 되었고, 특히 n-hexanal의 머무름시간(retention time)은 3.5분으로 아주 빨리 분리가 되었다. 그리고 Direct vapor injection 방법에 따른 n-hexanal의 정량시 각 시료의 n-hexanal 값은 10%이내의 오차를 보여주어, 고휘발성 향기성분중 n-hexanal의 정량분석이 가능하였다.

• Journal of Ecology and Environment
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• 제29권4호
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• pp.381-387
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• 2006

We analyzed the total yields and composition of essential oils in leaf extracts of Nepeta cataria by Gas Chromatography Mass Spectrometry (GC-MS). Thirty-six compounds representing 97.0% of total oil were detected. The major constituents of essential oils in Nepeta cataria were nepetalactone (90.9%), unidentified compound (Retention time 17.35; 1.82%), 1,8-cineol (1.49%), ${\beta}-caryophyllene$ (1.12%), and ${\beta}-pinene$ (1.078%). The volatile compounds in leaf extracts of N. cataria concentrated to nepetalactone ($88.83{\sim}93.33%$) remarkably. In the essential oil of N. cataria cis,trans-nepetalactone ($30.2{\sim}37.8%$) and cis,cis-nepetalactone ($31.5{\sim}37.0%$) were found as the main constituents. The effects of essential oil of N. cataria on the growth of six microorganisms (Bacillus cereus, B. subtilis, B. amyloliquefaciens, Escherichia coli, Staphylococcus aureus subsp. aureus, and Pseudomonas aeruginosa) were investigated. The essential oil of N. cataria had strong inhibitory effect on the growth of three fungal species (Bacillus cereus, B. subtilis, and B. amyloliquefaciens). The essential oil from N. cataria was found to have a low antimicrobial activity against Staphylococcus aureus subsp. aureus, while no activity were found against Escherichia coli and Pseudomonas aeruginosa. Results indicate the significant antimicrobial effect, which may be depended on the yield of nepetalactone.

• 상하수도학회지
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• 제24권1호
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• pp.5-14
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• 2010

A pilot-scale biological aerated filter (BAF) was operated with an anaerobic, anoxic and oxic zone at $23{\pm}1^{\circ}C$. The influent sCOD and total nitrogen concentrations in the feedwater were approximately 250 mg/L and 35 mg N/L, respectively. sCOD removal at optimum hydraulic retention time (HRT) of 3 hours with recirculation rates of 100, 200 and 300% in the column was more than 96%. Total nitrogen removal was consistently above 80% for 4 and 6 hours HRT at 300% recirculation. For 3 hours HRT and 300% recirculation, total nitrogen removal was approximately 79%. Based on fitting results, the kinetic parameter values on nitrification and denitrification show that as recirculation rates increased, the rate of ammonia and nitrate transformation increased. The ammonium loading rates for maximum ammonium removed were 0.15 and 0.19 kg $NH_3$-N/$m^3$-day for 100% and 200% recirculation, respectively. The experimental results demonstrated that the BAF can be operated at an HRT of 3 hours with 200 - 300% recirculation rates with more than 96 % removal of sCOD and ammonium, and at least 75% removal of total nitrogen.

• 펄프종이기술
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• 제44권4호
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• pp.62-68
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• 2012

This study was carried out to evaluate the effect of PCC loading at thick stock on the physical properties of paper. The effect of starch addition(2, 4 and 6%) and mixing time(5, 10 and 20 min.) on the filler retention and paper properties were investigated. Optimum dosage of cationic starch as a fixing agent was 4%, and mixing time did not showed any significant effect on the filler retention. PCC loading at thick stock was more effective to improve bulk and opacity than PCC loading at thin stock, although their improvement was not so significant. It was also found that the strength properties could be improved by the loading at thick stock. PCC loading method at thick stock could be considered as one of potential approaches for further improving of paper properties, although further research works are required in order to apply the PCC loading at thick stock in the paper mill.

• 한국물환경학회지
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• 제22권3호
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• pp.540-545
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• 2006

The anaerobic digester supernatant (ADS) with high $NH_4-N$ concentration often results in a $NH_4-N$ overloading to the mainstream process of municipal wastewater treatment plant (MWTP). The nitrogen removal from the ADS is therefore important in order to achieve a stable mainstream process performance as well as to prevent $NH_4-N$ overloading due to ADS. Recently because of several advantages compared to the full nitrification, many works have shown interests in controlling the build-up of $NO_2-N$ in nitritation processes. The application of nitritation could save the aeration power compared to the full nitrification processes. In addition, the denitrification of $NO_2-N$ could reduce organic carbon requirements compared to the $NO_3-N$ denitrification. The purpose of this research was to find out the characteristics of the ADS nitritation and $NO_2-N$ accumulating factors from the laboratory reactor study. As a result based on the long-term laboratory experiment, it can be concluded that the degree of nitritation was closely related with the availability of alkalinity, free ammonia (FA), solid retention time (SRT) and solid concentration in the nitritation reactor.