• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2002년도 추계학술발표회
• /
• pp.351-354
• /
• 2002

In this study, variation of electrochemical parameters and characteristics of lead immobilization due to phosphoric acid injection in soil were studied during electrokinetic remediation of lead contaminated soil. TCLP result showed about 100% of soil was satisfied TCLP regulation criteria. And injected ion from cathode reservoir by ionmigration was proportionate to concentration of phosphoric acid and elapsed time. Therefore, when removal is infeasible or not cost-effective, in situ immobilization method would be more effective.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.248-248
• /
• 2012

인산염을 기초로 한 다양한 촉매 기질의 합성과 더불어, 촉매활성를 가지는 여러 가지 전이 금속을 이러한 기질에 도입한 다양한 이종상 촉매가 개발되어 왔다. 우리는 phosphoric acid 와 zirconyl chloride을 이용하여 간단한 방법으로 ${\alpha}$-zirconium phosphate (Zr(HPO4)2.H2O)을 합성하였다. Phosphoric acid의 농도 변화에 따른 crystallinity의 변화를 XRD를 통해 분석하였고, FE-SEM을 통하여 형태를 확인 하였다. 특히, 합성한 각각의 생성물을 다양한 종의 amine을 이용하여 intercalation 반응을 수행하였다. 이를 XRD, TEM을 통하여 결정 구조 변화를 확인 하였고, 더 나아가 잠재적 촉매로서의 응용성을 연구할 예정이다.

• Bulletin of the Korean Chemical Society
• /
• 제27권12호
• /
• pp.2101-2103
• /
• 2006

• 대한화학회지
• /
• 제63권5호
• /
• pp.346-351
• /
• 2019

Mannich-type reactions of cyclic N-sulfimines with 2-trimethylsiloxyfuran and pyrazolin-5-one have been developed using phosphoric acid (PA) as an organocatalyst. 2-Trimethylsiloxyfuran underwent a vinylogous Mannich-type reaction with cyclic N-sulfimines in the presence of the PA catalyst to give sulfamidate ${\gamma}$-butenolides in good yields and with high diastereoselectivities (up to 90% yield and 7:1 dr). In addition, the reaction between pyrazolin-5-one and a diverse range of cyclic N-sulfimines provided access to sulfamidates in good to high yields (up to 94% yield).

• 월간산업보건
• /
• 통권371호
• /
• pp.28-31
• /
• 2019

피부, 눈 및 상부 호흡기의 자극 가능성을 최소화하기 위해, 인산(Phosphoric acid)에 대한 직업적 노출기준 TLV-TWA를 $1mg/m^3$, 그리고 TLV-STEL을 $3mg/m^3$으로 권고하였다. 수분이 있는 상태에서 인산 먼지나 인산 케이크에 의한 피부 접촉은 특히 자극적이다. TLV-TWA의 권고수준은 산에 노출 경험이 없는 노동자들에게 인후염을 일으키는 인산의 공기 중 농도보다 낮은 수준이다. 또한 인산 노출에 순응된 노동자들에게 유발할 수 있는 농도보다는 훨씬 더 낮은 수준이다. 피부(Skin), 감작성(SEN) 또는 발암성 경고표지(Notation)를 권고하기에는 충분한 자료가 없다.

• Restorative Dentistry and Endodontics
• /
• 제21권2호
• /
• pp.559-568
• /
• 1996

The purpose of this study was to evaluate the micro leakage of composite resin when various phosphoric acid agents were used to etch the enamel and dentin. In this study, class V cavities were prepared on the buccal surfaces of fourty extracted human molar teeth, and they were randomly assigned into 4 groups with 10 teeth. The cavities of each groups were etched with 10%, 32%, 35% and 37% phosphoric acids for 15 seconds, washed and dried and the cavities were restored with composite resin after application of the adhesive. The specimens were immersed in 2% methylene blue solution for 3 days. And then, the specimens were sectioned buccoligually. Degree of dye penetration at tooth-restoration interfaces was examined by Inverted Metallurgical Microscope at the occlusal and gingival margins. The result were as follows : 1. The degree of microleakage at occlusal and gingival margin in all group was statistically difference among 10% and 35% (P<0.01), 10% and 37% (P<0.01), 32% and 35% (P<0.05) and 32% and 37% (P<0.05) acid concentrations, but was not statistically difference between 10% and 32%, 35% and 37% acid concentrations (P>0.05). The degree of microleakage was showed to dimish with increase of acid concentration. 2. The degree of microleakage at the occlusal margin was statistically significant difference among 10% and 32%,10% and 35%, 10% and 37% acid concentrations(P<0.05). The degree of microleakage among 32% and 35%, 32% and 37% and 32% and 37% acid concentrations was not statistically significant difference. 3. In comparison of microleakage at the gingival margin, the degree of microleakage above 32% acid concentration was not showed less than 10% acid concentration (P>0.05). In comparison of 32%, 35%, 37% acid concentrations, the degree of microleakage at 35% and 37% acid concentrations was showed less than 32% acid concentration(P<0.05).

• KSBB Journal
• /
• 제7권2호
• /
• pp.118-125
• /
• 1992

1.에멀젼형 화장품시료의 오염정도는 P. aeruginosa의 증식을 촉진하는 fatty acids, waxs, oils, steroids 등의 유기물에 의존하였다. 2. 오염의 결과, 물성의 변화로서 화장품시료의 pH가 40일 경과시 7.6에서 6.0으로 변화되었다. P. aeruginosa의 영양원으로서는 상대적으로 낮은 굴절률을 갖는 물질들이 소모되어 화장품시료(물:오일=70:30)의 굴절률이 1.4430에서 1.4530으로 변화 되었다. 3. 오염이 진행되는 동안 화장품시료의 相의 안정서이 파괴되었으며, 약간의 변색, 변취와 함께 creaming 및 응집현상이 나타났다. 4. P. aeruginosa의 최적증식조건인 pH7.0, 온도$20^{\circ}C$에서, 물과 오일의 부피비에 의한 균증식은 70:30, 80:20, 30:70, 90:10, 50:50의 순서로 되었다. 5. 방부살균제를 첨가하여 challenge test를 한 결과, P. aeruginosa의 증식이 억제되었으며 40일 경과시 균수는 방부살균제를 첨가하지 않은 경우 $10^8$개/ml에서 p-hydroxy benzoic acid propyl ester + phosphoric acid buffer solution첨가로 $5{\times}10^3$ 개/ml로 감소되었다. 6. 시험균주인 P. aeruginosa에 대한 항균력은 p-hydroxy benzoic acid propyl ester + phosphoric acid buffer solution>p-hydroxy benzoic acid buthyl ester + acetic acid buffer solution>p-hydroxy benzoic acid methyl ester + phosphoric acid buffer solution>p-hydroxy benzoic acid methyl ester + p-hydroxy benzoic acid propyl ester>p-hydroxy benzoic acid buthyl ester + potassium chloride sodium hydroxide buffer solution>p-hydroxy benzoic acid buthyl ester + p-hydroxy benzoic acid propyl ester>p-hydroxy benzoic acid methyl ester + acetic acid vbuffer solution>acetic acid buffer solution _ potassium chloride sodium hydroxide buffer solution의 순으로 우수하였으며 pH, 농도, 균수등은 양호한 수준을 유지하였다.

• 한국산학기술학회논문지
• /
• 제13권2호
• /
• pp.926-933
• /
• 2012

일반적으로 비료용 인산은 황산과 인광석의 분해반응에 의해 생산되는데 이 반응은 발열반응으로써 온도가 상승하게 되면 생산수율 저하의 문제점이 따른다. 이를 해결하기 위해 인산제조공정에서는 불산(HF)과 사불화규소(SiF4)가 함유된 증기(vapor, $80^{\circ}C$)를 배출시키는 진공냉각기(vacuum cooler)를 운영하고 있으나, 이 과정에서 냉매 및 폴리실리콘 원료로 활용가능한 귀중한 자원(불소 & 규소)들이 버려지고 있다. 본 연구는 인산제조공정 부산물인 규불산(H2SiF6)으로 회수하기 위한 기초 실험연구로서, 불소회수 후 인산슬러리 내 불소 농도변화를 분석하여 규불산 회수가능량을 예측하였다. 회수 후 불소농도는 약 0.12wt% 감소하였고, 대상 비료공장의 생산규모를 고려할 경우 불소 회수가능량은 약 5,509 톤/년이었다. 한편 현장에서, 규불산의 농도는 0.35wt%에서 7.33wt%까지 농축되었고, 진공냉각기로부터 배출되는 증기유량은 $51,000m^3/hr$이었다. 또한 Pilot실험을 통한 불소 회수효율은 76.74%로 나타나, 실제 회수할 수 있는 규불산량은 5,340 톤/년으로 추정되었다.

• 한국세라믹학회지
• /
• 제32권2호
• /
• pp.189-196
• /
• 1995

Materials retaining electrolyte of a phosphoric acid fuel cell (PAFC) have been prepared with SiC powder to SiC whisker mixing ratios of 1:1, 1:2, 1:3, 1:4, 0:1 by a tape casting method. When 3wt% dispersant (sorbitan monooleate) is added to a matrix, the porosity of the matrix decreases a little while the bubble pressure and area of the matrix increase remarkably in comparison with no dispersant content. Effect of the electrolyte resistance and the polarization resistance on perfomance of a PAFC has been investigated using A.C. impedance spectroscopy. With the increase of whisker content, the electrolyte resistance decreases due to the increase of porosity and acid absorbancy, and the polarization resistance increases due to the increase of surface roughness. The polarization resistance affects current density predominantly at the higher potential than 0.7V becuase the polarization resistance is considrably larger than the electrolyte resistance. Both the electrolyte resistance and the polarization resistance affect current density near 0.7V of the fuel cell operating potential because they have similar values. The electrolyte resistance affects current density predominantly at the lower potential than the fuel cell operating potential because the electrolyte resistance is larger than the polarization resistance.

• Corrosion Science and Technology
• /
• 제4권1호
• /
• pp.8-14
• /
• 2005

The corrosion behaviour of mild steel in phosphoric acid solution in the presence and absence of pollutants viz. Chloride, Fluoride and Sulfate ions at 302K-333K was studied using mass loss and potentiostatic polarization methods. The addition of chloride and sulfate ions inhibits the mild steel corrosion in phosphoric acid while fluoride ions stimulate it. The effect of temperature on the corrosion behaviour of mild steel indicated that inhibition of chloride and sulfate ions decreased with increasing temperature. The adsorption of these ions (Chloride and sulfate) on the mild steel surface in acid has been found to obey Langmuir adsorption isotherm. The values of activation energy (Ea) and free energy of adsorption ($\Delta$) indicated physical adsorption of these ions (chloride and sulfate) on the mild steel surface. The plot of $logW_{f}$ against time (days) at 302K gives a straight line, which suggested that it obeys first order kinetics and also calculate the rate constant k and half-life time $t_{1/2}$.