• 한국환경보건학회지
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• 제8권2호
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• pp.33-46
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• 1982

This experiment was carried out for the purpose of reducing alkaloid in reconstituted tobacco sheet and effluent of reconstituted tobacco sheet manufacturing company by treating oxidizing agents such as ozone, sodium hypochlorite, perchloric acid and hydrogen peroxide to tobacco extract created from the manufacturing process of reconstituted tobacco sheet. The effect of alkaloid reduction in tobacco extract by the volume added, time of treatment and pH of oxidizing agents were as follows: 1. When the solid rate of tobacco extract stood at 10 percent, the content of alkaloid, total sugar, total nitrogen and chlorine was 1,600mg/l, 11,000mg/l, 3,200mg/l and 4,000mg/l, respectively. 2. The effect of alkaloid reduction through ozone treatment was in proportion to time of ozone treatment. Alkaloid showed a 31.2 percent reduction under 8 hours' ozone treatment and 0.23g ozone consumed to remove lmg alkaloid. 3. Alkaloid reduction through sodium hypochlorite treatment was influenced by quantity of chlorine in sodium hypochlorite solution. To remove lmg alkaloid, 36.3mg chlorine was used. Reduction of alkaloid was not affected by time of sodium hypochlorite treatment, while showed the best reaction under pH 5-7. 4. The effect of alkaloid reduction by perchloric acid was under the control of the volume added and time of treatment of perchloric acid. The volume of perchloric acid required to remove alkaloid was on the decrease as time of treatment was getting longer. lmg alkaloid was removed by 0.15g perchloric acid under 8 hours' perchloric acid treatment. 5. Alkaloid reduction reacted slowly to the volume added and time of treatment of hydrogen peroxide. Under 8 hours' hydrogen peroxide treatment, it showed maximum removal, registering 10 percent alkaloid reduction.

• 폴리머
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• 제24권6호
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• pp.869-876
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• 2000

소수성 표면성질을 나타내고 있는 poly(L-lactide-co-glycolide) (75 : 25 by mole ratio of lactide to glycolide, PLGA) 표면의 세포적합성을 증가시키기 위하여 물리화학적 처리방법으로 표면개질 하였다. 물리적 방법으로는 코로나 방전 및 플라즈마 처리가, 화학적인 방법으로는 70% 염소산, 50% 황산 및 0.5 N 가성소다 수용액으로 처리하였다. 처리된 PLGA 표면의 물접촉각은 73$^{\circ}$에서 50~60$^{\circ}$로 감소하였고 electron spectroscopy for chemical analysis의 분석결과, 알킬탄소는 감소되는 반면, 산소를 포함하는 탄소 관능기들이 상대적으로 증가함을 보여 친수화의 주원인으로 사료되었다. 섬유아세포의 배양 결과 control에 비하여 처리된 PLGA상에 점착 및 성장거동이 우월하게 관측되어 본 처리 방법이 세포적합성을 증가시켰다고 사료된다. 결론적으로 PLGA 표면의 적심성에 있어서 친수화는 세포의 점착 및 성장에 중요한 역할을 하늘 것으로 확인되었다.

• Journal of Ginseng Research
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• 제3권2호
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• pp.127-133
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• 1979

A simple and rapid colorimetric method for determination of panaxadiol and , panaxadiol was developed. 1. After heating with 60% perchloric acid, panaxadiol and panaxadiol yielded red.purple color with absorption maximum at 540 nm and 538 nm, respectively. 2. The maximum colors of the Panaxadiol and panaxadiol were reached when the algycones were treated at 6$0^{\circ}C$, 5 minutes or 7$0^{\circ}C$ 3 minutes. 3. The absorbance varied linearly with the amount of aglycone in the reaction mixture. And the colorimetric method was sensitive to about 10$\mu\textrm{g}$ of aglycone in 5.5ml of the reaction mixture. 4. The color was stable for about a week at 4$^{\circ}C$. 5. $\beta$-Sitosterol, oleanolic acid and cholesterol were not yielded red color by treatment with 60% perchloric acid under the conditions described.

• 한국식품과학회지
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• 제3권2호
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• pp.105-109
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• 1971

1) 열산처리(熱酸處理)에서 산(酸)의 농도(濃度)는 TCA, PCA 모두 5%이면 충분하다. 2)열산처리시간(熱酸處理時間)은 발색시간(發色時間)을 15분(分)으로 할 때 20이면 충분하다. 3) 20 분간(分間) 열산처리(熱酸處理)하면 발색시간(發色時間)은 15분(分)이면 된다. 4) PCA 농도(濃度)가 5% 이상(以上)에서는 RNA 전처리(前處理)에서는 영향을 미치지 않으나 발색(發色)시킬 때는 영향을 미치므로서 이때 PCA의 농도(濃度)를 일정(一定)하게 해줄 필요(必要)가 있다. 5) 발색(發色)시킬 때 시료(試料) 중(中)에 TCA가 5% 이상(以上) 공존(共存)하면 현탁되어 OD 측정(測定)이 불가능(不可能)하며 PCA처럼 농도차(濃度差)가 색도(色度)에 영향을 미칠 가능성(可能性)이 있으므로 열산처리(熱酸處理)는 TCA보다 PCA를 사용(使用)하는 것이 좋다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.465-469
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• 2006

Pre-treatment methods to determine various heavy metal contents in packaging papers were investigated by ICP-ES (Inductively Coupled Plasma Emission Spectrometry) analysis. Pre-treatment methods utilized in this study include dry ashing and decomposition methods ($HNO_{3-}HClO_{4-}HF,\;HNO_{3},\;and\;H_{2}SO_{4-}HNO_{3}$). They were compared with the conventional extraction (water) and migration (3% acetic acid) methods. The five representative heavy metals (Cd, As, Pb, Cr and Hg) were analyzed. For Cd, Hg, and As, the results were below detection limit of the instrument. In case of Cr and Pb, the migration test is considered to be a better method compared to the extraction test, but all pretreated methods showed much higher detection efficiency than the extraction or migration test. However, the detection ratio between the migration test and decomposition methods was different. Among all decomposition methods, the nitric acid - perchloric acid - hydrofluoric acid treatment brought a slightly higher detection value than others, but there was no significant difference among them except sulfuric acid - nitric acid method. Concerning Pb, the sulfuric acid - nitric acid method showed a low detection efficiency compared to other decomposition methods. The sulfuric acid - nitric acid method is, thus, not considered to be a suitable analysis method for Pb in packaging papers.

• 펄프종이기술
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• 제39권5호
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• pp.45-51
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• 2007

This study was carried out to investigate various heavy metal contents in packaging papers by pre-treatments for ICP-ES (Inductively Coupled Plasma Emission Spectrometry) analysis. Pre-treatment methods of heavy metals in this study include extraction, migration and decomposition methods (dry ashing, $HNO_3-HClO_4-HF,\;HNO_3,\;and\;H_2SO_4-HNO_3$). Test results were compared with conventional extraction (water) and migration (3% acetic acid) methods. The five representative heavy metals (Cd, As, Pb, Cr and Hg) were analyzed. For Cd, Hg, and As, the results were below detection limit of the instrumental technique. It was considered that the migration test was a better method compared to extraction test, but all the decomposition methods showed much higher detection values than the extraction or migration test. In case of recycled corrugated containers, 3% acetic acid solution extracted about 25% of chromium and 30% of lead compared to the content by decomposition methods. Among all decomposition methods, the nitric acid - perchloric acid - hydrofluoric acid treatment brought a slightly higher detection value than others, but there was no significant difference among them except sulfuric acid - nitric acid method.

• 폴리머
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• 제24권6호
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• pp.877-885
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• 2000

본 연구에서는 폴리락타이드 (PLA), 폴리글리콜라이드 (PGA) 그리고 이들의 공중합체인 PLGA 필름을 염소산 혼합용액 [70% 과염소산 (HClO$_4$)/포타슘 클로레이트 (KClO$_3$) 포화 수용액, 3 : 2]으로 처리하여 표면의 젖음성과 세포적합성을 증가시켰다. 표면 처리된 고분자의 표면을 물접촉각 측정과 ESCA, SEM으로 특성결정하였다. 염소산 처리된 PLA, PGA, 및 PLGA의 표면 젖음성은 처리시간이 증가함에 따라 증가되었고 이들 고분자 필름은 기존의 에탄을 전처리와 달리 건조 후에도 친수성 표면을 유지하였다. 세포 점착실험은 섬유아세포를 염소산 처리된 필름의 표면에서 1일 및 2일 배양하였고 표면의 젖음성이 증가함에 따라 세포의 점착도 우세하였다. 결론적으로 본 연구에서는 표면의 젖음성은 세포의 점착과 증식 거동에 중요한 역할을 한다는 것을 증명하였다.

• 한국식품과학회지
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• 제17권5호
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• pp.340-344
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• 1985

본(本) 연구(硏究)에서는 한천(寒天)의 조단백질(粗蛋白質). 회분(灰分)의 제거방법(除去方法) 및 gel강도(强度)에 미치는 영향(影響)을 검토(檢討)하였다. 조단백질(粗蛋白質) 및 회분(灰分)의 제거방법(除去方法)으로서 Trichloroacetic acid(TCA) 와 Perchloric acid(PCA)의 첨가처리(添加處理) 및 수침법(水浸法)을 사용(使用) 하였으며 그 결과(結果)는 다음과 같다. 조단백질(粗蛋白質) 제거공정(除去工程)에서 단백질(蛋白質) 침전제(沈澱劑)로는 PCA 가 TCA보다 더 효율적(效率的)이었다. 0.01% PCA 첨가시(添加時) 조단백질(粗蛋白質) 함량(含量)은 4.0%에서 1.0%로 감소(減少)하였고, gel 강도(强度)는 원료한천(原料寒天) 220g/$cm^2$에 대하여 402g/$cm^2$로 증가(增加)하였다. 회분제거공정(灰分除去工程)을 12시간(時間) 수침상태(水浸狀態)로 진탕함으로서 회분(灰分)이 8.7%에서 2.7%로 감소(減少)하였고 gel강도(强度)는 원료한천(原料寒天) 22/$cm^2$에 대해 530g/$cm^2$로 증가(增加)하였다. 그러나 회분함량(灰分含量)의 변화(變化)가 3% 미만에서는 gel강도(强度)에 미치는 영향(影響)이 거의 없었다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.149-149
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• 2017

Aluminum alloys have poor corrosion resistance compared to the pure aluminum due to the additive elements. Thus, anodizing technology artificially generating thick oxide films are widely applied nowadays in order to improve corrosion resistance. Anodizing is one of the surface modification techniques, which is commercially applicable to a large surface at a low price. However, most studies up to now have focused on its commercialization with hardly any research on the assessment and improvement of the physical characteristics of the anodized films. Therefore, this study aims to select the optimum temperature of sulfuric electrolyte to perform excellent corrosion resistance in the harsh marine environment through electrochemical experiment in the seawater upon generating porous films by variating the temperatures of sulfuric electrolyte. To fabricate uniform porous film of 5083 aluminum alloy, we conducted electro-polishing under the 25 V at $5^{\circ}C$ condition for three minutes using mixed solution of ethanol (95 %) and perchloric (70 %) acid with volume ratio of 4:1. Afterward, the first step surface modification was performed using sulfuric acid as an electrolyte where the electrolyte concentration was maintained at 10 vol.% by using a jacketed beaker. For anode, 5083 aluminum alloy with thickness of 5 mm and size of $2cm{\times}2cm$ was used, while platinum electrode was used for cathode. The distance between the two was maintained at 3 cm. Anodic polarization test was performed at scan rate of 2 mV/s up to +3.0 V vs open circuit potential in natural seawater. Surface morphology was compared using 3D analysis microscope to observe the damage behavior. As a result, the case of surface modification showed a significantly lower corrosion current density than that without modification, indicating excellent corrosion resistance.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.67-67
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• 2018

The 5xxx series aluminum alloys are recently used in not only marine system but also automotive area because of a low density material, good mechanical properties and better resistance to corrosion. However, Aluminum alloys are less resistant than the purest aluminum such as 1xxx aluminum alloy. Electrochemical anodization technique has attracted in the area of surface treatment because of a simple procedure, a low-cost efficiency than other techniques such as lithography and a large volume of productivity, and so on. Here, The relationship between the corrosion behavior and the thickness of aluminum anodic oxide have been studied. Prior to anodization, The 5052 aluminum sheets ($30{\times}20{\times}1mm$) were degreased by ultra-sonication in acetone and ethanol for 10 minutes and eletropolished in a mixture of perchloric acid and ethanol (1:4, volume ratio) under an applied potential of 20V for 60 seconds to obtain a regular surface. During anodization process, Aluminum alloy was used as a working electrode and a platinum was used as a counter electrode. The two electrodes were separated at a distance of 5cm. The applied voltage of anodization is conducted at 40V in a 0.3M oxalic acid solution at $0^{\circ}C$ with appropriate magnetic stirring. The surface morphology and the thickness of AAO films was observed with a Scanning Electron Microscopy (SEM). The corrosion behavior of all samples was evaluated by an open-circuit potential and potentio-dynamic polarization test in 3.5wt% NaCl solution. Thus, The corrosion resistance of 5052 aluminum alloy is improved by the formation of an anodized oxide film as function of increase anodization time which artificially develops on the metal surface. The detailed electrochemical behavior of aluminum 5052 alloy will be discussed in view of the surface structures modified by anodization conditions such as applied voltages, concentration of electrolyte, and temperature of electrolyte.