• 동의생리병리학회지
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• 제22권4호
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• pp.948-953
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• 2008

The purpose of this study was to analyze harmful heavy metals, sulfur dioxide and residual pesticides in 27 kinds of oriental medical materials. This study was carried out on 27 samples of oriental medical materials. The GC-ECD(Varian, CP-3800) was used to analyze residual pesticides. ICP-OES(Varian, Vista-MPX) was used to analyze lead, arsenic, cadmium. Mercury was analyzed by amalgamation method. A modified Monier-Williams method was used to analyze sulfur dioxide. Arsenic was detected less than 3(mg/kg) in 14 samples and was not detected 13 samples. Lead was detected less than 5(mg/kg) in 15 samples and was not detected 12 samples. Mercury was detected less than 0.2(mg/kg) in 15 samples and was not detected 12 samples. Cadmium was detected more than 0.3(mg/kg) in 3 samples was detected less than 0.3(mg/kg) in 16 samples and was not detected 11 samples. A few residual pesticides was detected, but all residual pesticides was safe. Sulfur dioxide was detected in all samples, but all residual sulfur dioxide was safe.

• 분석과학
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• 제12권2호
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• pp.171-175
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• 1999

Carbon paste electrodes, modified with podands containing more than two sulfur atoms, have been employed for the voltammetric determination of Ag(I) ion from aqueous solution. The voltammetric response was characterized with respect to paste composition, preconcentration method, kind of anion, variation of pH, Ag(I) ion concentration, and possible interferences. Linear calibration curves were obtained for Ag(I) ion concentration ranging from $1.0{\times}10^{-6}$ to $9.0{\times}10^{-5}M$, and detection limit was $5.0{\times}10^{-7}M$.

• Environmental Engineering Research
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• 제16권3호
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• pp.165-173
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• 2011

The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated microsand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of $C_{eq}=10\;{\mu}g/L$ were 500 mg/L for AA and GFH, 520-1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60-95%.

• 폴리머
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• 제33권5호
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• pp.435-440
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• 2009

가황제/가황촉진제의 비율이 서로 다른 CR(chloroprene)로 개질된 NR(natural rubber)고무복합재료에 대한 비등온 TGA 열분해곡선으로부터 Kissinger 및 Flynn-Wall-Ozawa의 해석방법을 적용하여 분해활성화 에너지를 구하였다. 각 샘플에 대해 Kissinger의 해석방법을 적용한 결과 매우 양호한 직선성을 보였으며 기울기로부터 얻은 활성화 에너지 값은 모든 샘플에 대해 $147.0{\pm}2.0$ kJ/mol로 거의 일정하였다. Flynn-Wall-Ozawa의 해석방법을 적용하여 전화율 $0.05{\sim}0.40$ 범위에서 계산된 분해활성화 에너지 값은 전화율의 변화에 따라 계속 변화하였고 전화율이 증가함에 따라 그 값도 증가하는 현상을 보여 주었으며, 평균활성화 에너지 값은 $211.6{\pm}19.0$ kJ/mol 이었다. 두 가지 해석 방법의 비교 연구로부터, 샘플들의 전체 분해반응은 반응 메카니즘이 서로 다른 여러 단계의 다중 반응으로 이루어 있는 것으로 생각할 수 있었다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.540-543
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• 2000

본연구에서는 Rhodococcus rhodochrous IGTS8 균주를 사용하여 고농도의 유상에서 탈황효율을 높이기 위한 오일 함유비, pH, 영양물질의 영향을 조사하였다. 오일 함유비에 의한 영향은 유상이 30%이하일 경우 그리 크지 않았으며, pH 조절에 의해 50%, 영양물질의 강화에 의해 32%의 탈황효율이 증가했다. 강화배지에서 pH를 조절하며 배양한 결과, 기존의 배양에 비해 136% 탈황효율이 증가했다.

• Journal of Photoscience
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• 제3권2호
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• pp.77-83
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• 1996

Photosensitization via the singlet oxygen ($^1O_2$) mechanism by the binuclear iron-sulfur center, denoted as [2Fe-2S], was investigated, using a highly purified ferredoxin (Fd) preparation from spinach leaves. Since the apoprotein of Fd contains a good number of amino acid residues that are readily reactive with $^1O_2$ and thus interfere with the detection of $^1O_2$ generated from [2Fe-2S], we attempted to deprive the $^1O_2$-sensitive residues of their $^1O_2$-scavenging capacity as much as possible by treating Fd with rose bengal plus 550 nm monochromatic light and thereby photooxidatively degrading these residues. The photochemically modified Fd was found to keep the structural integrity of its Fe-S group virtually unaffected by the treatment. By employing chemical trap method for measurement and examining the kinetic effects of azide and deuterium oxide on the reactions of $^1O_2$ with various trap compounds, we were able to demonstrate that [2Fe-2S] indeed acts as a photosensitizer via $^1O_2$. Further, the minimum quantum yield of $^1O_2$ production by [2Fe-2S] was estimated to be 0.0047.

• Elastomers and Composites
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• 제54권2호
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• pp.97-104
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• 2019

Emulsion styrene-butadiene rubber silica wet masterbatch (ESBR silica WMB) technology was studied to develop highly filled and highly dispersed silica compounds, involving the preparation of a composite by co-coagulating the modified silica and the rubber latex in a liquid phase. Previous studies have shown that when manufacturing ESBR silica WMB/Butadiene silica dry masterbatch (BR silica DMB) blend compounds, preparing BR silica dry masterbatch and mixing it with ESBR silica WMB gave excellent results. However, WMB still has the problem of lower crosslink density due to residual surfactants. Therefore, in this study, tetrabenzylthiuram disulfide (TBzTD) was added instead of diphenyl guanidine (DPG) in the ESBR silica WMB/BR silica DMB blend compounds and sulfur/CBS contents were increased to evaluate their cure characteristics, crosslink densities, mechanical properties, and dynamic viscoelastic properties. TBzTD was found to be more effective in increasing the crosslink density and to produce superior properties compared to DPG. In addition, with increasing sulfur/CBS contents, mechanical properties and rolling resistance were enhanced due to high crosslink density, but the abrasion resistance was not significantly changed because of the toughness.

• 동의생리병리학회지
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• 제21권4호
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• pp.1039-1044
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• 2007

We investigated the residual contents of sulfur dioxide ($SO_2$) on the 280 kinds of herbal medicines distributed at 8 cities including in Seoul, Busan, Daegu, Gwangju, Jecheon, Yeongju, Geumsan and Jeonju in Korea. The residual contents of $SO_2$ were determinated by modified Monier-Williams method. The residual contents of $SO_2$ were not detected at 206 products in total 280 products. However, it was detected below 100 ppm in 39 products, between 101 and 1000 ppm in 30 products and exceeded 1000 ppm in 5 products. $SO_2$ contents ranged 11 ${\sim}$ 2339 mg/kg (mean 293 mg/kg) at domestic samples distributed. Regardless of region, $SO_2$ contents were not found at Notopterygii Rhizoma, Ligustici Scinensis Rhizoma et Radix, Bombyx Batryticatus, Coicis Semen, Cnidii Rhizoma, Anemarrhenae Rhizoma, Gardeniae Fructus, Alismatis Rhizoma. But it's found at Batatatis Rhizoma, Paeoniae Radix and Codonopsitis Radix of every region collected the samples. $SO_2$ contents were not detected at 58 products which collected cultural fields of dometic. After treated with water wash and hot water extraction, the reduction rates of sulfur dioxide were appeared with 14.3% ${\sim}$ 40.4% and 55.2% ${\sim}$ 100.0%, respectively. These data will be used to establish a criteron of residual sulfur dioxide in herbal medicines.

• Bulletin of the Korean Chemical Society
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• 제29권6호
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• pp.1217-1223
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• 2008

A series of Zr,S co-doped $TiO_2$ were synthesized by a modified sol-gel method and characterized by various spectroscopic and analytical techniques. The presence of sulfur caused a red-shift in the absorption band of $TiO_2$. Co-doping of sulfur and zirconium (Zr-$TiO_2$-S) improves the surface properties such as surface area, pore volume, and pore diameter and also enhances the thermal stability of the anatase phase. The Zr-$TiO_2$-S systems are very effective visible-light active catalysts for the degradation of toluene. All reactions follow pseudo firstorder kinetics with the decomposition rate reaching as high as 77% within 4 h. The catalytic activity decreases in the following order: Zr-$TiO_2$-S >$TiO_2$-S >Zr-$TiO_2$>$TiO_2$$\approx$ P-25, demonstrating the synergic effect of codoping with zirconium and sulfur. When the comparison is made within the series of Zr-$TiO_2$-S, the catalytic performance is found to be a function of Zr-contents as follows: 3 wt % Zr-TiO2-S >0.5 wt % Zr-$TiO_2$-S> 5 wt % Zr-$TiO_2$-S >1 wt % Zr-$TiO_2$-S. Higher calcination temperature decreases the reactivity of Zr-$TiO_2$-S.

• 콘크리트학회논문집
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• 제13권4호
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• pp.406-413
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• 2001

본 연구는 기존 원심력 철근콘크리트관의 성능을 향상시킬 수 있는 방법으로 관체 표면을 일정한 두께로 방식 라이닝 모르타르로 처리함으로써 보다 더 내구적인 하수관을 개발하기 위하여 실시하였다. 이를 위해 원심력 철근콘크리트관 제작 시, 동시성형이 가능하고 촉진 증기양생 조건에서도 균열이 발생되지 않는 접착강도가 큰 폴리머 시멘트 모르타르를 제조하였다. 폴리머 시멘트 모르타르를 원심력 철근콘크리트관용 라이닝 재료로 사용하기 위한 기초적 실험결과, 보통 시멘트 모르타르에 비해 역학적 성질 및 내구성이 우수하였으며, 현장적용결과, 동시성형 및 양생조건에 따라 적용될 수 있는 방법은 다양하나, 폴리머의 종류에 관계없이 폴리머 시멘트비를 20% 이하로 하며, 양생온도는 8$0^{\circ}C$이하의 양생조건을 제안할 수 있었다. 또한 현장조건이 가능하면, 2일간 기중양생(2$0^{\circ}C$)을 실시하여 폴리머 시멘트 모르타르 속의 폴리머 필름이 형성된 후, 8$0^{\circ}C$에서 양생시키는 방법이 이상적인 것으로 나타났다.