• 한국응용과학기술학회지
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• 제29권1호
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• pp.149-158
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• 2012

본 연구에서는 올레산을 표면개질제로 사용하여 수열법을 통해 수산화 마그네슘을 합성하였다. 수산화 마그네슘은 알카리 조건에서 올레인산과의 반응을 통해 표면 개질된 마이크로 크기의 플레이크 형상을 갖는다. 수열합성에서 수산화 마그네슘 입자 생성의 조건은 pH, 온도 그리고 반응시간이 표면개질과 입자 형상의 주요 변수임을 확인하였다. 생성된 수산화 마그네슘 입자는 FE-SEM, XRD, FT-IR 그리고 TGA를 통해 확인하였다. 유기 용매 내에서의 분산성의 확인은 개질되지 않은 수산화 마그네슘과의 침전 테스트 비교를 통해 확인하였다.

• 환경위생공학
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• 제17권4호
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• pp.10-18
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• 2002

The changes of conventional clarification processe and an increase in treatment cost are required to meet increasingly stringent regulations related to the treated water quality. Although many enhanced coagulations have introduced to improve organic matter removal, the results to remove color, nitrogen and phosphorus as well as organic material have not been very efficient yet. In this context as new flocculation using calcium hydroxide and magnesum sulfate was carried out. The removal of waste matters such as SS, organic matter, COD, nitrogen and phosphorus contained in stock wastewater was carried out by using the combination of calcium hydroxide and magnesium sulfate. The flocculation was investigated as a function of coagulant dose, pH, mixing time, settling time and coagulant addition modes such as the sequential addition of the two coagulants and the simultaneous addition of them. The flocculation by the combination of calcium hydroxide and magnesium sulfate was compared with that by aluminum sulfate. The mechanism of flocculation was investigated as well. About 60% of COD in stock watewater was removed by flocculation with combination of calcium hydroxide and magnesium sulfate.

• 접착 및 계면
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• 제9권2호
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• pp.24-31
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• 2008

본 연구에서는 EVA 에멀젼에 내수성 및 기계적 특성을 향상시키기 위하여 금속 이온 가교제인 calcium hydroxide 및 magnesium carbonate를 사용하여 이온성 가교결합을 도입하였다. EVA 에멀젼 필름의 가교밀도, 열적특성, 표면자유에너지 그리고 인장강도, 파단신율 및 인열강도 특성을 고찰하였다. 금속 이온 가교제 양이 증가함에 따라 EVA 에멀젼의 가교밀도는 증가하였고, 이에 내수성과 $T_g$ 값도 증가하였다. 그러나 EVA 에멀젼 필름의 표면에너지 및 기계적 특성들은 다소 다른 거동을 보였다. Calcium hydroxide 0.4% 그리고 magnesium carbonate 0.5%를 첨가한 경우가 EVA 에멀젼에 강한 이온성 가교결합이 형성되어 가장 높은 표면 자유에너지 값과 인장강도 및 인열강도를 보였다. 그러므로 본 연구에서 calcium hydroxide 및 magnesium carbonate와 같은 금속 이온 가교제가 EVA 에멀젼의 내수성과 기계적 물성을 향상시킴을 확인하였다.

• 환경위생공학
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• 제17권3호
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• pp.89-98
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• 2002

The changes of conventional clarification process and an increase in treatment cost are required to meet increasingly stringent regulations related to the treated water quality. Although many enhanced coagulations have introduced to improve organic matter removal, the results to remove color, nitrogen and phosphorus as well as organic material have not been very efficient yet. The removal of waste matters such as SS, organic matter, color and turbidity contained in dyeing wastewater was carried out by using the combination of calcium hydroxide and magnesium sulfate. The flocculation was investigated as a function of coagulant dose, pH, mixing time, settling time and coagulant addition modes such as the sequential addition of the two coagulants and the simultaneous addition of them. The flocculation by the combination of calcium hydroxide and magnesium sulfate was compared with that by aluminum sulfate. The mechanism of flocculation was investigated as well. About 84% of color in dyeing watewater was removed by flocculation with combination of calcium hydroxide and magnesium sulfate.

• 환경위생공학
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• 제18권1호
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• pp.41-50
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• 2003

Traditionally the supernatant after chemical treatment of metal acid wastewater is discharged in environment. The supernatant can be used as a coagulant as it contains effective metals. The aim of this study is to investigate the feasibility of treatment of dyeing wastewater using the supernatant after treatment by magnesium hydroxide and dolomite($Ca{\cdot}Mg(CO_3)_2$), of acidic metal wastewater. In dyeing wastewater treatment with the supernatant, optimum pH and dosage were determined. COD, turbidity and color were analyzed to evaluate the performance of treatment. In the case of magnesium hydroxide, the optimum dosage was 10%(v/v) for supernatant A and 3%(v/v) for supernatant B. Color, turbidity and COD removal was 99~100%, 85~97% and 43~53%, respectively. In the case of dolomite, the optimum dosage was 10%(v/v) for supernatant A and 3% for supernatant B. Color, turbidity and COD removal was 96~99%, 62~9l% and 52~53%, respectively.

• 한국세라믹학회지
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• 제34권6호
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• pp.659-667
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• 1997

The effect of calcination temperature of Mg(OH)2 on the green density and densification of MgO was investigated. It was observed that the impure magnesium hydroxide powder showed a higher crystallization rate while it had a lower tendency of agglomeration between periclae crystallites, as compared to that of the pure magnesium hydroxide powder. In the case of calcination of the powders under 85$0^{\circ}C$, the impure powder showed the higher green and sintered density. In spite of higher green density upon the calcination over 100$0^{\circ}C$, the impure powder showed the lower sintered density, caused by exaggerated growth of the periclase crystallites. The highest sintered densities in the both powders were obtained at the calcination temperature of 100$0^{\circ}C$. And the green density was inversely proportional to the sintered density at the calcination over 100$0^{\circ}C$.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 추계학술논문집 1부
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• pp.364-366
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• 2011

Polyimide (PI) grafted magnesium hydroxide was synthesised and characterised by XRD, TGA, SEM analysis. XRD patterns of $PI/Mg(OH)_2$ carried the peaks due to $Mg(OH)_2$ with decreased intensity. The $CO_2$ adsorption capacity of $PI/Mg(OH)_2$ at $50^{\circ}C$ was found to be 14 wt% revealing chemisorption of $CO_2$ on $Mg(OH)_2$ which could be regenerated at higher temperatures.

• 자원리싸이클링
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• 제23권3호
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• pp.21-29
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• 2014

본 논문은 마그네슘 함량이 매우 높은 특징을 갖는 볼리비아 우유니호 염수로부터 리튬을 회수하는 공정의 설계에 필요한 기초 자료를 얻을 목적으로 수행되었으며, 농축된 용액에 수산화칼슘의 첨가하여 수산화마그네슘을 침전시키는 반응에 있어서 용존 이온의 농도에 미치는 반응온도, 반응시간, pH 등 제 인자들의 영향을 조사하였다.

• Restorative Dentistry and Endodontics
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• 제1권1호
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• pp.26-32
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• 1975

After a vital pulpotomy in dogs' teeth, the responses of the remaining pulp tissue under hydroxides (calcium hydroxide, magnesium hydroxide, aluminium hydroxide and zinc hydroxide) were studied histologically. The class V cavities were prepared on the teeth and the pulp was amputated. Each hydroxide was placed over the amputated tissue and the cavity was sealed with zinc oxide eugenol cement. Animals were sacrificed after 3 days, 1, 2, and 3 weeks following the operation. The teeth were decalcified, sectioned and stained with hematoxylin and eosin. Microscopic examination reveals as follows; 1. Calcium hydroxide: Inflammatory change was seen in the superficial portion of the remaining pulp tissue at the 3rd day and 1st week. The incompleted calicified material began to be deposited from the canal wall at the 2nd week, and the advanced calcified material was seen at the 3rd week. 2. Magnesium hydroxide: Severe inflammatory change was seen in the superficial portion of the remaining pulp from the 3rd day and the 1st week samples. Inflammatory change was decreased at the 2nd week and the slight calcified material was deposited from the root canal at the 3rd week. 3. Aluminium hydroxide: Severe inflammatory changes were seen in the remaining pulp tissue, the blood vessel was dilated, and the odontoblasts were destroyed at the 3rd day and 1st week. The fibrous degeneration spread to the apex at the 2nd week. There was no evidence of newly formed odontoblasts or deposition of calcified material underneath aluminium hydroxide. 4. Zinc hydroxide: The micrscopic picture was destructive. A thick necrotic layer was found under the amputated surface at the 3rd day and 1st week. Granulation tissue formation as well as chronic inflammatory changes extended to the apical area in the pulp tissue. Also there were no sign of odontoblastic formation or calcified material at the 2nd and 3rd week.

• 한국표면공학회지
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• 제44권2호
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• pp.44-49
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• 2011

The films formed on AZ31B magnesium alloy were prepared from alkaline solution composed of potassium permanganate and sodium hydroxide. The immersion tests were carried out at the different concentration of sodium hydroxide and pre-treatment method in 5 minute. The morphology and the phase composition of the film were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion behavior of the film in 5.0% NaCl solution was evaluated using potentiodyanmic polarization. Open circuit potential in developing film was examined with time. The thin and transparent film was mainly composed of MgO and $Mg(OH)_2$. The film with the best corrosion resistance was obtained at $70^{\circ}C$ bath temperature, 1.6 M concentration of sodium hydroxide and chemical pre-treatment.