• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.119-120
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• 2023

Corrosion of the steel rebar in coastal environment caused huge economical loss of the globe. Therefore, coating on the steel rebar being used to mitigate the corrosion. In the present study, we have applied epoxy coating on arc thermal sprayed Al coating (a dual metal/polymeric coating) vis-à-vis compared with as coated one (Al coating). The corrosion studies were performed in simulated concrete pore solution with 3.5 wt. % NaCl solution. The morphology of the dual epoxy/Al coating is smooth while Al coating shows rankle and defects. Due to defects, Al coating is susceptible to corrosion while dual epoxy/Al coating has performed excellent compared to as coated one at extended period of immersion.

• Corrosion Science and Technology
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• 제11권6호
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• pp.232-241
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• 2012

This work focused on corrosion of carbon steel bolted GECM/Al parts in tap water and NaCl solutions. In tap water and NaCl solutions, open circuit potential of GECM and its potentials in a series of carbon steel bolt>Ti>Al became active. Regardless of test materials, open circuit potentials in tap water were noble, and increasing NaCl concentration, its potentials became active. Immersion test of single specimen showed that no corrosion occur in Ti and GECM. In tap water, carbon steel bolt didn't show red corrosion product and in chloride solutions, corrosion rate in 1% NaCl solution was greater than its rate in 3.5% NaCl solution and red corrosion product in 1% NaCl solution was earlier observed than that in 3.5% NaCl solution. It seems that this behavior would be related to zinc-coatings on the surface of carbon stee l bolt. On the other hand, aluminium was corroded in tap water and chloride solutions. Corrosion of aluminium in tap water was due to the presence of chloride ion in tap water by sterilizing process.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1999년도 춘계학술발표회 초록집
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• pp.1-1
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• 1999

• 한국재료학회지
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• 제31권12호
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• pp.704-709
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• 2021

In the flux used in the batch galvanizing process, the effect of the component ratio of NH₄Cl to ZnCl₂ on the microstructure, coating adhesion, and corrosion resistance of Zn-Mg-Al ternary alloy-coated steel is evaluated. Many defects such as cracks and bare spots are formed inside the Zn-Mg-Al coating layer during treatment with the flux composition generally used for Zn coating. Deterioration of the coating property is due to the formation of AlCl_x mixture generated by the reaction of Al element and chloride in the flux. The coatability of the Zn-Mg-Al alloy coating is improved by increasing the content of ZnCl₂ in the flux to reduce the amount of chlorine reacting with Al while maintaining the flux effect and the coating adhesion is improved as the component ratio of NH₄Cl to ZnCl₂ decreases. Zn-Mg-Al alloy-coated steel products treated with the optimized flux composition of NH₄Cl·3ZnCl₂ show superior corrosion resistance compared to Zn-coated steel products, even with a coating weight of 60 %.

• 한국주조공학회지
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• 제20권1호
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• pp.38-45
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• 2000

The remelting for recycling or thin aluminum scrap, such as aluminum chip generally involves melting of these pieces submerged in molten salt flux. In this study, the effects of salt flux compositions and alloying elements on the aluminum dropletscoalescence and oxide film removal were studied in 99.8%Al, Al-1.01%Cu, Al-1.03%Si, and Al-1.38%Mg alloys as a function of holding time at $740^{\circ}C$ Salt fluxes based on NaCl-KCl(1:1) with addition of 5wt.% fluorides(NaF, $Na_3AlF_6$, $CaF_2$) or 5 wt.% chloride($MgCl_2$, $AlCl_3$) were used. The experimental results show that NaCl-KCl(1:1) with addition of 5 wt.% fluorides exhibits better coalescence ability than that with chlorides. The oxide film is not removed by NaCl-KCl(1:1) with addition of 5 wt.%chlorides, while it is removed by NaCl-KCl(1:1) with addition of 5 wt.% fluorides. The aluminum droplets coalescence and oxide film removal by salt fluxes are related to interfacial tension tension between metal and salt flux.

• 대한화학회지
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• 제50권1호
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• pp.46-52
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• 2006

착물을 촉매제로 하여 용매인 CH2Cl2와 산화제 NaClO를 사용하여 올레핀 산화반응의 메카니즘 연구를 하였다. 이들 반응에서 포르피린의 치환기는 TPP(5,10,15,20-Tetraphenylporphyrin)와 (p-X)TPP(X=CH3O, CH3, F, Cl)를, 올레핀은 styrene과 (p-X)styrene (X=CH3O, CH3, Cl, Br)을 사용하였다. 일반 효소반응에서 잘 알려진 Michaelis-Menten식에 따라 Km과 Vmax 값을 구하였다. Michaelis-Menten 식의 속도 파라미터를 포르피린 치환기에 따라 측정하고, 이들 파라미터와 치환기상수 간의 상관성을 조사함으로써 올레핀 산화반응의 중간체 M-oxo-olefin의 형성 과정과 분해 과정이 촉매활성이나 속도 결정 단계의 변화에 미치는 영향을 분석 하고자 하였다.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2001년도 춘계학술발표대회
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• pp.79-79
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• 2001

This study was conducted to measure the total protein, DNA, and RNA contents of corpus luteum(CL) in various stages of estrous cycle and pregnancy. CLs were collected from a local slaughterhouse and stages of the estrous cycle of CL were classified as CL1~2, days 1 to 10; CL3(with/without central cavity), days 11 to 17; CL4, days 18 to 20 by method of Ireland et. al(1980) and stages of the pregnancy of CL were classified as P1~3, months 11~3: P4~6, months 4~6; P7~9, months 7~9 of pregnancy. CL3 with/without central cavity(CC) was identified as described by Kastelic et. al.(1990)-CL with CC, more than 2mm in diameter; CL without CC, less than 2mm in diameter. In total protein content, CL3 with CC was significantly lower than P7~9(p<.05). The total DNA content was lower in CL3 with CC than CL3 without CC and CL4(p<.05). In protein : DNA ratio, CL3 with CC was significantly lower than CL4(p<.05), CL3 without CC was significantly lower than P7~9(p<.05), CL4 was significantly lower than CL3 with CC, P1~3 and P7~9(p<.05). No differences were observed in RNA content, protein:RNA ratio, RNA/DNA of CLs in stages of estrous cycle and pregnancy.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.325-325
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• 2006

Cationic polymerization of isobutyl vinyl ether using various metal halides was examined in toluene in the presence of an added base at $0^{\circ}C$. In conjunction with an appropriate weak base such as ethyl acetate or 1,4-dioxane, all metal halides but $FeBr_{3}\;and\;GaCl_{3}$ led to living cationic polymerization. The polymerization rates varied as follows: $FeBr_{3},\;GaCl_{3}\;>\;FeCl_{3}\;>\;SnCl_{4}\;>\;InCl_{3}\;>\;ZnCl_{2}\;>>\;AlCl_{3},\;HfCl_{4},\;ZrCl_{4}\;>\;EtAlCl_{2},\;BiCl_{3},\;TiCl4\;>>\;SiCl_{4}\;>\;GeCl_{4}$. This order partially corresponds to that of the equilibrium constant in the formation of a carbocation from a chloroalkane in the presence of a carbonyl compound. With extremely active Lewis acids, such as $FeBr_{3}\;and\;GaCl_{3}$, the use of a stronger base, THF, was required to achieve living polymerization.

• 한국세라믹학회지
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• 제23권1호
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• pp.33-43
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• 1986

The synthesis of high-purity AlN by a vapor-phase reaction was investigated using the $NH_3-AlCl_3-H_2$ reacting system. The theoretical yields of AlN were determined from th thermodynamic equilibrium composi-tions. It was shown that the yields above 90% could by obtained even in the range of relatively low temper-ature of 600-1200K. The reaction temperature and the initial amounts/ratios of the reacting gases showed significant effects on the yields but the total pressure did not. The experimental results showed that a high-purity AlN having a needle shape was the only product as a solid phase and its amount produced increased with the reaction temperature. While the degree of agglmera-tion of the synthesized AlN increased with the reaction temperature the size of each particle consisting of the agglomerates was independent of the temperature but grew from 0.09 to 0.115${\mu}{\textrm}{m}$ with the flow rate of NH3. These experimental results were compared with the theoretical aspects for the synthesis of a high-purity AlN.

• 한국수소및신에너지학회논문집
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• 제16권1호
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• pp.92-101
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• 2005

[ $Li_3AlH_6$ ] (5.6wt% theoretical hydrogen storage capacity) powders with and without Ti-containing dopants have been successfully synthesized by mechanochemical reaction near room temperatures from mixtures of LiH and $LiAlH_4$ powders. It has been observed that single phase $Li_3AlH_6$ could be obtained within 2-3 hours of milling, but the addition of reactive $TiCl_2\;or\;TiCl_3$ to the starting mixtures. caused partial decomposition of $LiAlH_4$ into LiCl and free Al with gaseous $H_2$. By addition of these reactive dopants to the as-synthesized $Li_3AlH_6$, this problem could be solved. The addition of 2 mol% $TiCl_2\;or\;TiCl_3\;to\;Li_3AlH_6$ decreased the decomposition start temperature up to 30-50$^{\circ}C$, while that of Ti or $TiH_2$ did not change the thermal decomposition behavior of $Li_3AIH_6$.