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명반석을 이용한 알루미나 시멘트의 제조 (II) (알루미나 시멘트의 특성)
한기성,최상욱,송태웅 한국세라믹학회 1979 한국세라믹학회지 Vol.16 No.3
In the previous paper, it was reported that formation of desirable calcium alunimate(CA) in clinker was considerably affected by sulfur-contaminated alumina which was prone to form a disadvantageous mineral, $C_4A_3S$. In this study, however, sulphate-free alumina cement was made from sulfur-free alumina refined from alunite and corresponding materials. The major minerals in the clinker were identified by X-ray diffraction patterns as calcium aluminate (CA), calcium dialuminate $(CA_2)$ and dicalcium alumino silicate $(C_2AS)$. The formation of CA was more effective with decreasing contents of silica to 2 per cent or less and sulfur in the refined alumina. Physical properties of prepared alumina cement such as setting time, stability and compressive strength were measured. The values were similar to those of commercial alumina cements.
포틀랜드시멘트 클링커융액의 결정화에 관한 연구($K_2O$와 MgO의 영향)
한기성,문정연,김용국 한국세라믹학회 1982 한국세라믹학회지 Vol.19 No.3
The crystallization of melts with similar composition of Portland cement liquid containing 0-5% $K_2O$ was studied by differential thermal and isothermal reaction. The devitrification of melts was occured in stages, the recognizable amount of CaO was appered at the first step, then proto-C3A was crystallized. The latter showed to occur in both cubic C3A and Ca-ferrite crystallization. Batches lost remarkable amounts of $K_2O$ as a result of volatilization during melting and the solubility of $K_2O$ in the melts was unstable.
석고에 고용된 $P_2O_5$가 $C_3A$의 초기수화에 미치는 영향
한기성,김용국 한국세라믹학회 1984 한국세라믹학회지 Vol.21 No.4
The effect of 2% of $P_2O_5$ substituted in gypsum(5 mol% as $HPO_3$) on the early hydration characteristics of $C_3A$ were investigated and then gypsum only and gypsum mixed with $Ca(H_2PO_4)_2$.$H_2O$(2% as $P_2O_5$) were studied separately for comparison. The early hydration reaction of $C_3A$ with each gypsum were examined by measuring the rate of heat libera-tion of hydration with calorimeter and by analysing the hydration products with X-ray diffractometer and differential thermal analyser. It was shown that phosphogypsum substituted with $P_2O_6$ in the crystal lattice accelerated exceedingly the formation of the ettrignite and following hydrated products. However the other gypsum especially gypsum without any phosphate delayed the formation of various hydration products, It was consequently suggested that when phosphogypsum are used as the retarder of cement setting its reta-rding effect for setting of cement is not ascribed to the retardation of ettringite formation.
한기성,김태영,이경훈 대한건축학회 2020 Architectural research Vol.22 No.2
The purpose of this study is to examine the influence of remoteness between exit stairways on evacuationperformance. Firstly, we reviewed the design regulations of the U.S., the U.K., and South Korea, in relation to remotenessbetween Exit stairways. Secondly, evacuation simulation was implemented, in order to evaluate the adequacy of eachstandard. Eight tall buildings in South Korea were selected for the simulation. Evacuation performance was assessed fordifferent remote distances between Exit stairways. Lastly, this research analyses the evacuation simulation data statisticallyin relation to the effect of remoteness on evacuation time. We found that as the distance between two exit stairwaysincreases, the total evacuation time and average evacuation time for evacuees decreases. There was no statistical influencebetween the maximum travel distance of the evacuee and the remoteness between two exit stairways, but there was asignificant effect on the average travel distance of the evacuees. In addition, the results from the optimal point showed thatthe L_ratio had the highest evacuation time at 0.44, while the D_ratio had the highest evacuation time at 0.38.
한기성,최상흘 한국세라믹학회 1978 한국세라믹학회지 Vol.15 No.2
Influence of cooling atmosphere on the whiteness in white portland cement was studied. The effective composition of gaseous medium of cooling atmosphere is desirable less than 0.5% of $O_2$ and 0.5~1.5% of CO. When theclinker is quenched in nitrogen atmosphere, the color of clinker becomes bright pink. In a weakly reducing gaseous medium or vacuum, the absence of oxygen brings defects in crystal and transformation in the coordination of iron, and as a result, whiteness is raised.
한기성,최상흘,한상목,서일영 한국세라믹학회 1975 한국세라믹학회지 Vol.12 No.4
Hydration processes of the rapid hardening cement clinkers, which were synthesized from domestic alunite for major alumina source, limestone, kaolin and fluorite, were investigated by means of x-ray diffraction analysis, thermal analysis and microscopic observation etc. The clinkers were composed mainly of alite, calcium fluroaluminate (C11A7.CaF2) minerals. While the hydratio processes of the clinkers are altered by concentration of SO3 in the paste, calcium aluminate hydrates such as C4AH13, CAH10 and calcium monosulfate hydrate (C3A.CaSO4.12H2O) are formed at first and then some of them are transformed into ettringite(C3A.3CaSO4.32H2O) within 30~60 min. when the concentration of SO3 in the paste are enough. However the formed ettringite are changed slowly into calcium monosulfate hydrate as the concentration of SO3 become lowered, and the paste is hardened with these close-packed minerals. When the content of SO3 in clinker is so enough, calcium sulfoaluminate hydrates are found without any addition of anhydrite or hemi-hydrite.
한국 석회석의 열분해특성 및 가열에 의한 상변화에 관한 연구
한기성,안기상,최롱,Han, Ki-Sung,Ahn, Ke-Sang,Choi, Long 한국세라믹학회 1983 한국세라믹학회지 Vol.20 No.1
The investigations have been carried out to study the characteristics of limestone using in Korean cement industry with prime interests in the dissociation and thermal phase changes of limestone between 90$0^{\circ}C$ and 140$0^{\circ}C$ The range of decomposition temperature of limestone was 840-87$0^{\circ}C$ and it was considered that the temperature was lowered by impurities in the limestone. The more the impurities and the finer the grain size of quartz in limestone the lower temperature was applied in forming $C_2S$ mineral the temperature of about 100$0^{\circ}C$. The major clinker minerals such as $C_3S$, $C_2S$, $C_3A$ and $C_4AF$ were formed in most of limestone when the firing temperature was up to 130$0^{\circ}C$.
명반석을 이용한 알루미나 시멘트의 제조(I) (Monocalcium Aluminate의 합성)
한기성 한국세라믹학회 1978 한국세라믹학회지 Vol.15 No.4
In the present investigation, refined alumina obtained from alunite locally available was used as a aluminous source to synthesize monocalcium aluminate $(CA)_3$ the major mineral constituent of alumina cement. The influence of $SiO_2$ and $Fe_2O_3$ contents on the formation of monocalcium aluminate was studied by X-ray diffraction analysis mainly. About 0.8-1.0 of $Al_2O_3/C_3O$ mol ratio and less than 4 percent of $SiO_2$ were desirable for the effective formation of CA. The small amount of alkali and sulphur contents contained in refined alumina from alunite as the impurities were affected to form $C_4A_3S$ and $C_3S_2$, disadvantageous compounds for the alumina cement, therefore the impurities should be restricted in minimum content as possible.