• 상하수도학회지
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• 제18권5호
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• pp.573-579
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• 2004

Electroflotation, which is used as an alternative to sedimentation, is a separation treatment process that uses small bubbles to remove low-density particulates. Making allowances for recent collision efficiency diagram based on trajectory analysis, it is necessary to tailor zeta potential of bubbles that collide with negatively charged particles. In this paper, the study was performed to investigate the effects of magnesium and aluminium ions on zeta potential of bubbles. And, it was studied to find out factors which could affect the positively charged bubbles. Consequently, zeta potential of bubbles increased both with higher concentration of metal ions and in the acidic pH value. And, a probable principle that explained the procedure of charge reversal could be a combined mechanism with both specific adsorption of hydroxylated species and laying down of hydroxide precipitate. It also depended on the metal ion concentration in the solution to display its capacity to control the bubble surface.

• Bulletin of the Korean Chemical Society
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• 제28권10호
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• pp.1683-1688
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• 2007

This paper presents a novel simple method for introducing gold nanoparticles in a poly(4-vinylpyridine) (PVP) polymer layer over a glassy carbon (GC) electrode with the aim of forming a tunable electrochemical interface against a cationic ruthenium complex. Initially, AuCl4 ? ions were spontaneously incorporated into a polymer layer containing positively charged pyridine rings in an acidic media by ion exchange. A negative potential was then applied to electrochemically reduce the incorporated AuCl4 ? ions to gold nanoparticles, which was confirmed by the FE-SEM images. The PVP layer with an appropriate thickness over the electrode blocked electron transfer between the electrode and the solution phase for the redox reactions of the cationic Ru(NH3)6 2+ ions. However, the introduction of gold nanoparticles into the polymer layer recovered the electron transfer. In addition, the electron transfer rate between the two phases could be tuned by controlling the number density of gold nanoparticles.

• 한국환경과학회지
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• 제8권2호
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• pp.211-219
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• 1999

Surface complexation models(SCMs) have been performed to predict metal ion adsorption behavior onto the mineral surface. Application of SCMs, however, requires a self-consistent approach to determine model parameter values. In this paper, in order to determine the metal ion adsorption parameters for the triple layer model(TLM) version of the SCM, we used the zeta potential data for Zeolite and Kaolinite, and the metal ion adsorption data for Pb(II) and Cd(II). Fitting parameters determined for the modeling were as follows ; total site concentration, site density, specific surface area, surface acidity constants, etc. Zeta potential as a new approach other than the acidic-alkalimetric titration method was adopted for simulation of adsorption phenomena. Some fitting parameters were determined by the trial and error method. Modeling approach was successful in quantitatively simulating adsorption behavior under various geochemical conditions.

• 한국염색가공학회지
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• 제15권1호
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• pp.1-7
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• 2003

To study the dyeability(ΔE value) and color depth of silk fabrics dyed with Impatiens balsamina extracts. its flower, leaf and stem was extracted by water. This paper investigated some experiments under the various dyeing conditions such as dyeing temperature, dyeing time, repetition of dyeing, dyeing pH with silk fabrics dyed with Impatiens balsamina extracts. The results obtained were as follows 1. It was found that $\lambda_{max}$ of silk fabrics dyed with Impatiens balsamina extract was 260nm and its flower, leaf , stem and different colored flower(white, pint violet) had same $\lambda_{max}$ at 260nm. 2. $\Delta{E}$ values were increased when dyeing temperature, repetition of dyeing and time was higher, value of munsell of silk fabrics dyed with Impatiens balsamina extract was Yellow-Red. But dyeing temperature, repetition of dyeing and time was higher, shifted to longer wavelenth side. 3. Silk fabric dyed with Impatiens balsamina extracts at acidic pH was colored reddish Yellow-Red, alkali bath colored yellowish Yellow-Red in silk fabrics dyed with Impatiens balsamina extract.

• 한국비블리아학회지
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• 제12권2호
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• pp.71-84
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• 2001

도서관 소장용 자료의 장기보존에 관한연구를 수행하였는데, 크게 세부분으로 구분된다： 종이, 마이크로 필림(MF), 전산매체. 첫째로, 19~20세기에 생산된 산성용지의 보존대책을 위한 열화원인과 열화도를 평가하여 그 특성을 분석하고, 도서의 보존을 위한 보존환경, 탈산처리 방법을 통한 보존처리의 메카니즘을 연구하였다. 둘째로, 마이크로필림의 보존성을 위한 재료의 물리.화학적 성질, 현상과정의 산화물, 보존수명과 관련된 재료의 원인분석을 하였다. 그리고 셋째로, 전자환경에서의 전산매체의 수명, 저장용량, 생존능력, 노후력 극복 등의 자료의 저장조건과 요구조건 등의 장기보존방안을 제시하였다.

• 한국대기환경학회지
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• 제19권1호
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• pp.101-112
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• 2003

Biological methods are frequently used for treatment of contaminated air, containing volatile organic compounds and odor compounds in low concentrations and high flow rate of air streams. For more than 20 years. biofilter has been recognized as a cost effective technology for the purification of contaminated air. Most commercial applications before 1990 were for control of odors. In the past decades major progress has been accomplished in the development of vapor phase bioreactor. in particular biotrickling filers. Biotrickling filters are more complex than biofilters. but are usually more effective, especially for the treatment of compounds which are difficult to degrade or compounds that generate acidic by-products. While the level of understanding of biotrickling filtration process for VOCs still remains limited. the evidence success of biotreatment of VOC in air resulted in pursuing active research. This paper presents fundamental and practical aspert of VOCs treatment from air in biotrickling filter. Special emphasis is given to the operating parameters and the factors influencing performance for biotrickling filter.

• 한국미생물·생명공학회지
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• 제23권1호
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• pp.68-74
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• 1995

A bacterial strain A-6 producing the high level of an extracellular inulin fructotransfe rase(depolymerizing)(EC 2.4.1.93) which converts inulin into di-D-fructofuranose dianhydride III (DFAIII) was isolated from soil. The isolated strain could be classified as a species belonging to the genus Arthrobacter based on its morphological and physiological characteristics identified in this work. Production of the enzyme was induced by inulin, and the highest activity was detected in the slightly acidic medium supplemented with 2.5% inulin and 0.1% trypton as a sole carbon and a nitrogen source, respectively. Under the optimal conditions, the enzyme activity in the culture supernatant reached approximately 60 uints/ml after 96 hours of cultivation. The optimum pH and temperature for the crude enzyme preparation from Arthrobacter sp. A-6 were pH 5.0 and 60$\circ$C , respectively. The DFA produced by the action of the inulin fructotransferase was confirmed to be DFAIII by paper chromatography, HPLC and $^{13}$C-NMR spectroscopy.

• Journal of Dairy Science and Biotechnology
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• 제32권1호
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• pp.37-45
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• 2014

Benzoic acid is widely used in the food industry as a preservative in acidic foods, owing to its antimicrobial activity against various bacteria, yeasts, and fungi. Benzoic acid occurs naturally in different foods such as fruits, vegetables, spices, and nuts as well as in milk and dairy products. Lactic acid bacteria convert hippuric acid, which is naturally present in milk, to benzoic acid; therefore, the latter could also be considered as a natural component of milk and milk products. Benzoic acid is also produced during the ripening of cheese by the propionic acid fermentation process that follows lactic acid fermentation. This paper, we provide basic information regarding the systematic control of natural benzoic acid levels in raw materials, processing intermediates, and final products of animal origin.

• 한국인쇄학회:학술대회논문집
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• 한국인쇄학회 2001년도 국제학술발표회
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• pp.45-45
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• 2001

자료의 보존에 있어서 종이의 열화로 인해 자료의 분석, 열화메커니즘의 해석, 종이의 보존이란 측면 하에서의 관심이 서서히 집중되고 있는 실정이며, 그 중요성도 크게 대두되고 있는 실정이다. 산성지를 중성화하는 화학적시스템, 즉, 탈산성화처리는 알카리계금속(Ca, Mg, Zn, Na)과 유기용매, 수용성용매를 이용하여 이들 약품을 종이내에 침투시켜 중성화(pH 6-8) 함으로써 종이의 주성분인 cellulose를 보다 안정화시키는 방법으로 산을 중화하여 보존성을 향상시킬 수 있는 것이다. 즉, 탈산처리란 화학적으로 종이속에 생기는 산 또는 산을 발생하는 물질을 알칼리물질로 중화하는 것이다. 또한 중화후 알칼리 물질이 종이에 잔류하면 장래에 내부적으로 발생하는 산이나 외부(대기중의 오염물질 등) 로부터 침입하는 산도 중화하여 보존성을 향상시킬 수가 있다. 따라서, 본 연구는 산성초지법에 의해 제조된 용지들의 열화특성과 알카리 토금속을 처리한 후에 알카리도를 상승시킨 용지의 열화특성을 물리·화학적 변화를 통하여 종이의 보존성을 비교 검토·규명함으로써 문(도)서의 보존체계를 마련하고자 하며, 보존과 관련된 기초자료를 얻고자 실시하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.213-216
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• 2006

As form a part of way to improve the durability of concrete placed on deleterious environments such as acidic rivers, sewage wastewater, and sewer system, the paper presented here is the results of experimental immersion test, and for the test solution, 4 types sulfuric acid solution was prepared. From the result of EDS analysis of cement paste at 180 days of immersion, the detected major chemical elements were Ca and S and they are assumed as composing elements of gypsum. A comparative study between prediction models from the Japanese Standard and the present study corresponding to $d=C\sqrt{t}$ and $d=\alpha{\cdot}t^n$ respectively accorded well with each other, as being 0.98 of determination coefficient.