• Asian-Australasian Journal of Animal Sciences
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• 제12권2호
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• pp.271-281
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• 1999

The cost of production of high quality pork is compensated by high returns, but constraints by the market are increasing. A few opportunities to maintain and improve pork quality by dietary means are presented. The healthy value of pork is a prerequisite. A careful control of suppliers and preservation of feeds are essential to protect pork against presence of contaminants from the feed. The feeding level and some dietary components modify the partition of the dietary energy into different pig tissues and chemical components of pork, affecting the hygienic and nutritional value, tenderness and taste. It is difficult to transfer a nutrient from the diet to pork, if the requirements. for growth are satisfied. Fatty acids and Vitamin E are the most studied exceptions. There is some evidence that iron and selenium contents can be affected too. Varying the content of a nutrient frequently changes sensorial and technological properties of pork. The addition of oils improves the acidic profile of depot fats, but the effect on phospholipid composition is not well studied and negative effects on oxidability and consistency of meat products are observed. Vitamin E can improve many healthy and sensorial characteristics, but its effect is clearer when the meat is stressed or manipulated.

• 한국환경과학회지
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• 제11권3호
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• pp.227-234
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• 2002

Laboratory experiments were conducted to examine the behavior of metalaxyl in environment which was used as pesticide in green soil of golf course and as functions of the characteristics of adsorption, desorption and degradation in soil texture and organic matter contents. Acid water containing metalaxyl was conducted to evaluate the effects on adsorption, desorption and degradation. The adsorption of metalaxyl played more significant role in organic contents than clay contents, and pH Increases more pH 2.5 than pH 5.6. The desorption of metalaxyl from contaminants soil decreased higher organic contents LS-soil than S-soil, but the desorption amount of metalaxyl increased more pH 5.6 than pH 2.5. The rate of degradation of metalaxyl in green soil environmental increased higher organic contents LS-soil than S-soil and decreased more pH 2.5 than pH 5.6. These results indicated that the behavior of metalaxyl of the green soil was affected the soil texture of the golf course. Increasing of organic contents, the adsorption amount of metalaxyl on soil increased. Moreover the decrease of the pH of solution increased adsorption amounts and decreased desorption amounts. As the results, the transportation of metalaxyl in soil decreased the acidic rates. The acidification of soil by the acid rain increased the adsorption amount of metalaxyl, but the degradation of metalaxyl decreased. Therefore, it is possible to sustain contamination in run-off the stream and ground water by residuals in soil.

• 한국전기전자재료학회논문지
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• 제21권5호
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• pp.402-410
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• 2008

Single-walled carbon nanotubes (SWCNTs) were currently produced together with some contaminants such as a metallic catalyst, amorphous carbon, and graphitic nanoparticles, which should be sometimes purified for their applications. This study aimed to develop efficient, scalable purification processes but less harmful to SWCNTs. We designed three-step purification processes: acidic treatment, surface functionalization and soxhlet extraction, and heat treatment. During the soxhlet extraction using tetrahydrofuran, specifically, carbon impurities could be easily expelled through a glass thimble filter without any significant loss of CNTs. Finally, SWCNTs were left as a bulky paper on the filter through membrane filtration. Vertically aligned SWCNTs on one side of bulky paper were well developed in a speparation from the filter paper, which were formed by being sucked through the filter pores during the pressurized filtration. The bucky paper showed a very high peak current density of field emission up to $200\;mA/cm^2$ and uniform field emission images on phosphor, which seems very promising to be applied to vacuum microelectronics such as microwave power amplifiers and x-ray sources.

• Nano
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• 제13권10호
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• pp.1850123.1-1850123.9
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• 2018

The cetyltrimethyl ammonium bromide (CTAB)-modified montmorillonite (MMT) was synthesized via a novel "dissolution and reassembly" method. To determine the optimal formula, the adsorption of C.I. Reactive Red 2 (X3B) with CTAB/MMT was investigated. The optimal CTAB/MMT nanocomposite was used to remove 2,6-dichlorophenol and p-nitrophenol from aqueous solutions. The adsorption results can be described by Langmuir isotherm, and the adsorption capacities were 200 mg/g and 125 mg/g for 2,6-dichlorophenol and p-nitrophenol, respectively. To realize the quick separation and recycle, the magnetic CTAB/MMT was further strategized and synthesized. The adsorption equilibrium time was 15 min for both contaminants; the ions' strength showed a little bit of influence on the adsorption performance. In addition, compared with acidic condition, neutral condition was more beneficial to the adsorption reaction. Due to the addition of $Fe_3O_4$, the adsorption capacities of this magnetic nanocomposite for 2,6-dichlorophenol and p-nitrophenol were a little bit decreased, which were 170 mg/g and 91 mg/g, respectively. However, the magnetic nanocomposite can be separated within 30 s under an external magnetic field, which would be useful in the practical application.

• 분석과학
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• 제21권3호
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• pp.191-200
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• 2008

의약물질(PPCPs)은 수질 환경 시료에서 새로운 오염물질로 대두되고 있다. 본 연구에서는 LC/ESI-MS/MS를 이용하여 환경 수질 시료로부터 7 종(2-퀴노사린카르복시산, 아세틸살리실산, 디클로페낙-소듐, 나프록센, 이부프로펜, 메페남산, 탈니플루메이트)의 산성의약물질을 동시 분석하는 방법을 비교하여 개선하였으며 폐수처리장의 유입수 및 방류수 그리고 연장선상의 하천수의 오염도를 측정하였다. LC/ESI-MS/MS 분석을 위해서 MCX (Mixed Cation eXchange) 카트리지와 HLB (Hydrophilic-Lipophilic Balance) 카트리지를 연결하는 텐뎀 고체상 추출법과 MCX 카트리지만을 사용하는 고체상 추출법을 이용하여 효과적인 시료 정제 및 추출을 수행하였다. 검출한계(LODs)와 방법검출한계(MDLs)는 각각 0.05~1.50 pg/mL, 0.17~4.90 pg/mL 범위를나타내었다. 시료중 1.0 ng/mL 농도(n=3)에서절대회수율은 81.9%~116.3%를 나타내었다. 수질 환경 시료에서 수 pg/mL~ng/mL의 농도로 산성의약물질이 측정되었다.

• 대한환경공학회지
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• 제30권4호
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• pp.423-429
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• 2008

유기물과 무기물이 함께 오염되어 있는 합성 폐수처리에 대한 망간첨착활성탄(Mn-AC)의 적용성을 연구하였다. 유기물과 무기물의 대표물질로 페놀과 3가 비소를 각각 선정하였다. 산성조건에서 Mn-AC의 안정성을 평가하기 위해, 용액의 pH를 2, 3 및 4로 달리하여 시간경과에 따른 용존망간의 용출능을 평가하였을 때, pH 3보다 낮은 조건에서는 Mn-AC의 안정성이 떨어졌지만, pH 4에서는 반응시간동안 용출되는 망간의 농도는 무시할 수 있는 정도였다. 이러한 안정성 실험결과 Mn-AC는 pH 4 이상의 일반폐수 처리에 사용할 수 있음을 알 수 있었다. AC와 비교하였을 때, 망간첨착에 의한 비표면적 감소로 인해 망간첨착활성탄의 페놀제거속도 및 페놀 흡착능은 일부 감소하였다. 페놀 농도 변화에 따른 등온흡착결과 Mn-AC의 최대흡착량은 AC의 75%에 해당하였다. 산성영역의 pH에서는 Mn-AC에 의한 3가 비소 산화효율이 AC보다 높았지만 pH 7 이상에서는 반대 경향을 나타내었다. 본 연구를 통하여 Mn-AC를 페놀과 3가 비소의 동시처리에 적용할 수 있음을 알 수 있었다.

• 생명과학회지
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• 제8권4호
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• pp.421-425
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• 1998

식품양념으로 사용되고 있는 Polygonum hydropiper로부터 분리된 polygodial의 향진균 활성은 Saccharomyces cerevisiae 4균주, Zygosaccharomyces 속의 3균주, 그리고 Aspergillus 속의 5균주를 포함하는 식품 오염균들에 대해 그 MIC와 MFC들을 측정하여 조사되었다. 모든 효모성 진균들은 $3.13{\mu}g$/ml이하의 MIC와 MFC를 갖는 강한 항진균감수성을 나타내었다. 또한 polygodial의 항진균활성에 대한 다양한 온도와 pH들의 효과가 S.cerevisiae를 대상으로 조사되었다. $4^{\circ}C$에서, polygodial의 살균활성(MFC)은 배양 시간과 함께 점진적으로 증가하여 5기간만에 최고($3.13{\mu}g$/ml의 MFC)에 도달하였다. 30-$45^{\circ}C$의 온도 범위에서, polygodial의 살균활성은 온도 상승에 비례적으로 증가하였으며 특히 $45^{\circ}C$에서는 $0.1{\mu}g$/ml의 농도에서도 가능하였다. 한편 배지 pH는 또한 polygodial의 항진균 활성에 큰 영향을 주는 것으로 나타났다. 즉, 중성에 비해 산성(pH 3) 및 염기성(pH 9) 배지는 polygodial의 항진균(정균 및 살균)활성을 각각 8배, 2배 상승시켰다.

• 보존과학회지
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• 제30권1호
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• pp.27-32
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• 2014

본 논문에서 보존처리 한 책은 1935년 일본사에서 발행된 "위인최후(偉人最後)の언엽집(言葉集)"이다. 1900년대 초반의 책들은 대부분이 산성지로 되어있어 책의 산도가 높고 스테이플로 인한 갈변현상이 심하다. 본 시료도 갈변현상이 관찰되었으며, 책의 pH가 3.2로 매우 낮았다. 스테이플에 의한 갈변 이외에 종이 전체의 색이 많이 변하였으며, 종이 자체의 산성도로 인하여 종이가 바스러지는 현상이 보였다. 스테이플 철심을 제거한 후 건식, 습식클리닝을 행하여 오염물을 제거하였다. 가볍게 프레스하여 종이를 건조시킨 후, 미농지($4g/m^2$)를 사용하여 속지와 겉 표지를 배접하여 보강처리를 하였다. 본 논문에서는 스테이플 심을 대신하여 실이나 종이로 다시 묶는 기존의 보존처리 방법과 다르게 기존의 스테이플과 유사한 철심을 만들어 원래의 자리에 복원하는 작업을 하였다. 복원 하기 위해 스테이플의 두께와 비슷한 철사를 사용하였고, 착색액 ($H_2O$, $C_2H_5OH$, $CuSO_4{\cdot}5H_2O$, $FeCl_3{\cdot}6H_2O$)에 넣어 부식된 스테이플 심과 유사한 색으로 착색하였다. 마지막으로 20%의 paraloid B-72로 방식처리를 하여 차후의 부식을 예방하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권6호
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• pp.87-100
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• 2016

Biochar, which has high alkalinity, has widely studied for amendment of soil that contaminated with heavy metals. The aim of this study is assessment of amendment for arsenic and heavy metals contaminated acidic agricultural soil using biochar that derived from buffalo weed (A. trifida L. var. trifida). Pot experiments were carried out including analysis of soil solution, contaminants fractionation, soil chemical properties and plant (lettuce) uptake rate. Arsenic and heavy metals concentrations in soil solution showed relatively low in biochar added experiments when compared to the control. In the heavy metals fractionation in soil showed decrease of exchangeable fraction and increase of carbonates fraction; however, arsenic fractionations showed constant. Soil chemical properties indicated that biochar could induce recovery of soil quality for plant growth in terms of soil alkalinity. However, phosphate concentration in biochar added soil decreased due to Ca-P precipitation by exchangeable calcium from biochar. Arsenic and heavy metals uptake rate of plant in the amended experiment decreased to 50% when compared to the control. Therefore biochar derived from buffalo weed can be used as amendment material for agricultural soil contaminated with arsenic and heavy metals. Precipitation of As-Ca and metal-carbonates are major mechanisms for soil amendment using char.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권4호
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• pp.50-57
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• 2013

For the last couple of decades, the Fenton (-like) systems have been extensively studied for oxidation of organic contaminants in water. Recently, zero-valent iron (ZVI) has received attention as a Fenton catalyst as well as a reducing agent capable of producing reactive oxidants from oxygen. In this study, the ZVI-based Fenton reaction was assessed for the oxidative degradation of phenol using $ZVI/O_2$, $ZVI/H_2O_2$, ZVI/Oxalate/$O_2$ and hv/ZVI/Oxalate/$O_2$ systems. Reaction parameters such as pH and reagent dose (e.g., ZVI, $H_2O_2$, and oxalate) were examined. In the presence of oxalate (ZVI/Oxalate/$O_2$ and hv/ZVI/Oxalate/$O_2$ systems), the degradation of phenol was greatly enhanced at neutral pH values. It was found that ZVI accelerates the Fenton reaction by reducing Fe(III) into Fe(II). The conversion of Fe(III) into Fe(II) by ZVI was more stimulated at acidic pH than at near-neutral pH values.