• Tribology and Lubricants
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• 제18권1호
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• pp.16-23
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• 2002

For increasing the yield stress of ER fluids, the compressing ER electrode was developed and the compressing electrorheological (ER) behavior of anhydrous ER fluids in silicone oil of phosphorous ester cellulose powder was investigated. Under constant electric field, not only the current density but also the yield stress of anhydrous ER fluids were studied as varying the compressing length of ER electrode distance. From the experimental results the compressing of ER electrode had a large influence to the ER properties of anhydrous ER fluids. The current density was proportional to the compressing length of ER electrode under constant electric field and volume fraction also tile compressing yield stress was proportional to the volume fraction of dispersed particles under constant electric field and compressing length. When the ER electrode was compressed with 150mm after charging the electric field, 4 kV, tile yield stress of phosphoric ester cellulose ER fluids increased to thirteen times comparing with the yield stress measured at normal electrode.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.138-145
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• 2001

For increasing the yield stress of ER fluids, the compressing ER electrode was developed and the compressing electrorheological (ER) behavior of anhydrous ER fluids in silicone oil of phosphorous ester cellulose powder was investigated. Under constant electric field, not only the current density but also the yield stress of anhydrous ER fluids were studied as varying the compressing length of compressing ER electrode. From the experimental results, the compressing of ER electrode had a large influence to the ER properties of anhydrous ER fluids. The current density was proportional to the compressing length of ER electrode under constant electric field and volume fraction also the compressing yield stress was proportional to the volume fraction of dispersed particles under constant electric field and compressing length. When the ER electrode was compressed with 150mm after charging the electric field, 4 kV, the yield stress of phosphoric ester cellulose ER fluids increased to thirteen times comparing with the yield stress measured at normal electrode.

• 농약과학회지
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• 제9권1호
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• pp.97-101
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• 2005

피라졸 계통의 유기인계 살충제인 flupyrazofos(O,O-diethyl O-1-phenyl-3-trifluoromethylpyrazo-5-yl phosphorothioate)의 합성공정에서 생산된 원제 1(95.4%), 원제 2(97.6%) 그리고 정제품(99.2%)에 대한 불순물 조성과 함량을 조사하였으며, 이들 원제 및 정제품을 이용하여 in vitro와 in vivo 상에서 acetylcholinesterase (AChE) 활성 저해 정도를 비교 검정하였다. 실험결과 불순물의 조성은 O,O,O-triethylthio-phosphoric acid (TEA), 1-phenyl-3-trifluoromethyl-5-ethoxy pyrazole(PTMEP), O,O-diethyl O-1-phenyl-3-trifluoromethylpyrazo-5-yl phosphoric acid ester(flupyrazofos oxon), O,S-diethyl O-1-phenyl-3-trifluoromethylpyrazo-5-yl phosphorothionate (S-ethyl flupyrazofos)이었으며, 이들 불순물들의 함량이 원제 중에서 전반적으로 높았다. In vitro 상에서 AChE 저해는 불순물들이 많은 원제 1에서 가장 빠르게 저해되었으며, 생쥐 뇌 AChE (in vivo)에 대한 $I_{50}$ 값은 원제 1과 2가 정제품 보다 40% 이상 높았다. 이는 정제품에 비하여 원제 중에 더 많이 함유된 flupyrazofos oxen과 S-methyl flupyrazofos에 의한 영향일 것으로 판단되었다.

• 대한치과보철학회지
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• 제24권1호
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• pp.125-138
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• 1986

It is considered that etching solution or material itself of phosphoric ester cement will induce not a little pulpal irritation, if applied directly onto unsealed dentinal tubules. This study was designed to confirm above consideration by comparing two different conditions between $Ca(OH)_2$-based and non-$Ca(OH)_2$-based group. Posterior teeth of 15 male dogs were selected for this experiment. One experimental group was filled with cement after $Ca(OH)_2$-basing and enamel-etching, the other experimental group after enamel etching without $Ca(OH)_2$-basing. And both of two experimental groups were observed at 2 hours, 15 hours, 3 days, 1 week, 2 weeks, 4 weeks, and 6 weeks after filling. The findings reached to the following conclusions histologically. 1. In both groups, the damaged odontoblasts were atrophied and eventually disappeared. 2. In non-based group at early stage, odontoblasts were severely atrophied and defective areas were appeared between odontoblast cell layers. However, in based group, the odontoblasts were arranged slight irregularly. 3. In non-based group, a small number of undifferentiated cells below the odontoblast cell layers started to appear at 1 week after filling. However, in based group, the undifferentiated cells were appeared at 15 hours after filling. 4. In non-based group, formation of reparative dentin was not begun until late stage of experiment. However, in based group, formation of reparative dentin matrix was begun at 2 weeks after filling and very thickened reparative dentin was formed at 6 weeks after filling. 5. In odontoblast cell layers of both groups, dilated capillaries were observed. 6. Argyrophilic fibers were reticularly condensed in zone of Weil, and they were connected to the pulp tissue and dentin.

• Korean Membrane Journal
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• 제9권1호
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• pp.43-51
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• 2007

This paper describes the preparation and characterization of two kinds of fluorinated polybenzimidazole (PBI)s which can be potentially used for phosphoric acid-doped, high-temperature polymer electrolyte membrane fuel cells. Two kinds of perfluorocyclobutane (PFCB)-containing monomers were prepared via following synthetic steps; after fluoroalkylation of methyl 3-(hydroxy) benzoate and methyl 4-(hydroxy) benzoate with 1,2-dibromotetrafluoroethane and subsequent Zn-mediated dehalogenation, these compounds were cyclodimerized at $200^{\circ}C$ affording the ester-terminated monomers containing PFCB ether groups. The synthesized intermediates and monomers were characterized using FT-IR, $^1H-NMR,\;^{19}F-NMR$, and mass spectroscopy. The fluorinated PBIs were then successfully prepared through the solution polycondensation of the monomers and 3,3'-diaminobenzidine in polyphosphoric acid. Compared with traditional PBI, the glass transition temperatures of the fluorinated PBIs were obtained at $262^{\circ}C\;and\;269^{\circ}C$ which are lower than that of PBI and their initial degradation temperatures were still high over $400^{\circ}C$ under nitrogen. The fluorinated PBIs showed higher d-spacing values and improved solubility in several organic solvents as well as phosphoric acid, which confirmed they could be good candidates for the high temperature fuel cell membranes.

• 청정기술
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• 제26권2호
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• pp.116-121
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• 2020

본 연구에서는 유가금속 회수를 한 전기차 폐배터리 부산물의 재활용에 관하여 연구하였다. 폐배터리 부산물에는 희토류들이 남아있으나, 부산물의 형태로는 소재로서의 가치가 없기에 정제과정을 거쳐 희토류 산화물로 회수하였다. 희토류침전분말 형태의 부산물을 30% 수산화나트륨을 이용하여 가공이 편한 수산화물로 변환한 뒤, 옥살산의 용해도 차이를 이용하여 남아 있는 불순물을 정제한 뒤, D2EHPA (Di-(2-ethylhexyl) phosphoric acid)를 사용하여 이트륨을 분리하였다. 과망가니즈산 칼륨을 이용하여 세륨을 분리 후, PC88A (2-ethylhexylphosphonic acid mono-2-ethylhexyl ester)를 사용하여 란타넘과 네오디뮴을 분리하였다. 그 후 800 ℃의 온도에서 소성하여 란타넘, 네오디뮴 산화물로 재생하는 방법을 확인하였다.

• 한국환경농학회지
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• 제12권2호
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• pp.176-183
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• 1993

신규 살충제인 KH-502의 안전성을 조사하기 위하여 다양한 조건하에서 광(光) 분해(分解) 실험을 수행하였다. 이 실험에서 KH-502를 acetone 또는 acetonitrile 용액에 첨가한 뒤 태양광선 또는 자외선 $(300{\sim}350nm)$을 조사(照射)하였고, acetone 또는 acetonitrile 용액에는 수분함량, 산소함량이 달랐으며, 부식산,rosebengal 또는 tryptophan이 첨가 되었다. KH-502의 안전성 및 분해경향에 대한 결과를 요약하면 다음과 같다. 1. KH-502의 광분해(光分解)는 자외선을 조사(照射)한 경우와 그렇치 않은 경우에 매우 유의성있는 차이를 보여 주었다. KH-502는 acetone 용매에서 광관여효과에 의해 광분해(光分解)되었으나, acetonitrile 용매 하(下)에서는 광분해되지 않았다. 2. KH-502의 광분해 경향은 열 분해 경향과 판이하게 달랐으며, 광분해산물은 KH-502 oxo형, S-ethyl KH-502, PTMHP 및 몇가지 미지물질 등이었다. 3. acetone 또는 acetonitrile에 첨가된 부식산, rosebengal, tryptophan은 KH-502의 광분해에 광관여효과를 나타내지 않았다. acetone 용매의 용존산소는 acetone과 함께 경쟁적으로 광관여효과를 나타내어 KH-502의 분해를 촉진시켰다. 4. acetone 용매를 부식산 또는 논물로 처리했을때, KH-502의 광분해는 감소하였다.

• 한국환경농학회지
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• 제11권3호
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• pp.225-234
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• 1992

Thermal decomposition was conducted to investigate the influence of the various factors on stability of a new insecticide, [O, O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl) thiophosphoric acid ester : KH-502], in view of those informations applicable for industrial exploitation. In the thermal decomposition experiment, KH-502 was, after mixing with Fe, Cu and adjustment of moisture and pH conditions, subjected to three temperatures, 25, 50, and $100^{\circ}C$. Results for stability, and degradation pattern of KH-502 from the above experiment can be summarized as follows: 1. Main products of the thermal decomposition when this was conducted in the closed system were identified as following five compounds:O, O, O-Triethylthiophosphoric acid(TEPA), 1-Phenyl-3-trifluoromethyl-5-ethoxypyrazole(PTMEP), 1-Phenyl-2-ethyl-3-trifluoromethyl-5-hydroxypyrazole(PETMHP), O, O-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phosphoric acid ester(KH-502 oxo form), O, S-Diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl)phospho rothiolate(S-ethyl KH-502). However, compounds such as oxo form and S-ethyl KH-502 were not identified when the thermal decomposition was proceeded in the open system. 2. KH-502 was stable at 25 and 50$^{\circ}C$, but it was decomposed at 100$^{\circ}C$ following the first-order kinetics at the early stages of decomposition. 3. Rate constants for the thermal decomposition of KH-502 at 100$^{\circ}C$ were in the orders of Cu powder addition 0.344>Cu plate addition 0.21>moisture addition 0.05>closed system=open system=iron addition=pH 5.5 adjustment 0.04>pH 8.5 adjustment 0.027 day$^{-1}$, representing KH-502 was decomposed fast at Cu powder treatment and slow at pH 8.5 adjustment. 4. Half-life for the thermal decomposition of KH-502 at 100$^{\circ}C$ was in the orders of Cu powder addition 2.02

• 한국안전학회지
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• 제7권3호
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• pp.22-29
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• 1992

Emulsion-type cometics contain many kinds of carbon and energy source i.e., vegetable oil, mineral oil and carbohydrate etc., those can be used as nutrients and caused contamination by microbials. Thereby we have to keep cosmetics from the possibility of contamination by microbials. From this viewpoint, the purpose of this study is to get the data necessary not only to prevent dermatopathia occurred by microbials but also to sustain the quality. In this experiment, we observed how many Staphylococcus aureus were grown in the prepared cosmetics with or without antiseptics so as to prevent contamination. When the contamination proceed, the stability of phase was disturbed and creaming phenomina was happened with some discoloration and bad smell. About 40 days after, the pH was changed from 7.6 to 6.5 and the refractive index of cosmetic raw materials were changed from 1.4415 to 1.4490(water : oil=70:30). By adding antiseptics Into prepared cosmetics, the number of Staphylococcus aureus with challenge test method were decreased to 7$\times$103 cell/ml. For the antibacterial effect against Staphylococcus aureus, p-hydroxy benzoic acid propyl ester in phosphoric acid buffer solution was the best.

• 한국산학기술학회논문지
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• 제18권1호
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• pp.216-221
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• 2017

폴리머 안경렌즈를 제조할 때 가시광선 영역에서 투과되는 빛을 증가시키고, 안경렌즈 표면에 형성되는 허상을 방지하는 반사방지 기능은 매우 중요하다. 본 연구에서는 굴절률 1.56, 1.60 및 1.67을 갖는 안경렌즈를 폴리머 렌즈 모노머 및 이염화 이부틸 주석 촉매제, 알킬 인산 에스터 이형제 등의 혼합물을 인젝션 몰드 방법으로 열중합 공정을 적용하여 제조하였다. 폴리머 안경렌즈 표면에서의 반사방지 효과를 조사하기 위하여 다층 박막 반사방지 코팅 구조(양면 또는 단면 코팅), 3층 박막의 Gaussian gradient-index profile 불연속 근사 반사방지 코팅 구조, 3층 박막의 quarter-wavelength 근사 반사방지코팅 구조 등 다양한 반사방지 코팅 구조를 설계하였고, E-beam 증착 시스템을 이용하여 열중합공정으로 제조된 폴리머 안경렌즈에 각각 코팅하였다. 폴리머 안경렌즈의 광학적 특성은 UV-visible spectrometer로 분석하였다. 반사방지 코팅 층을 구성하는 박막의 굴절률, 표면 거칠기 등의 소재 특성은 Ellipsometer와 원자힘 현미경(AFM)으로 분석하였다. 분석결과, 굴절률 1.56의 낮은 굴절률을 갖는 폴리머 안경렌즈에서 가장 효과적인 반사방지 코팅 구조는 다층 박막 반사방지 코팅 구조의 양면코팅이었다. 하지만 굴절률 1.67의 고굴절률 안경렌즈에 대해서는 3층 박막의 Gaussian gradient-index profile 불연속 근사반사방지 코팅 구조의 양면 코팅도 다층박막 반사방지 코팅구조의 양면코팅에 상응하는 반사방지 효과를 나타내었다.