• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.479-485
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• 1998

Raw mateials such as limestone quartzite bauxite and anhydrite were used in the production of mod-ified beloite cement. Two kinds of clinker were synthesized with relatively higher content of $C_2S$ than that of $C_4A_3{\={S}}$ Concerning $C_2S$ the main mineral component borax ($Na_2O\;2B_2O_3\;10H_2O$) was added to stimu-late hydraulic reactivity and this would be possible by stabilizing ${\alpha}'-C_2S$ at room temperature. We had in-tended to compare burning and hydraulic characteristics of clinkers with one another by varying the amount of borax addition and to study the appropriate amount of anhydrite addition needed in the strengthening of cement during hydration. It was concluded that the effective amount of borax addition ne-eded for stabilization of ${\alpha}'-C_2S$ was 5 wt% in 60wt% $C_2S$ inclusive clinker and adding anhydrite in the ra-tio of 1.3 of $SO_3/Al_3O_3$ was appropriate in the production of cement by this clinker. Only ettringite was seen to contribute to the strength without additives but C-S-H was found to form along with ettringite with the addition of borax in the initial stage of hydration.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.415-420
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• 2010

Purpose: Heterotopic calcification is a pathological event in which deposits of calcium salts build up, usually in the joint area or soft tissues. It can occur under many conditions and in some rare cases may develop in burn scars. In particular, ulcerations in burn scars accompanied by heterotopic calcification are difficult to treat through conservative treatment. This study reports methods for accurate diagnosis and adequate treatment of ulceration in burn scars accompanied by heterotopic calcification. Methods: Fourteen patients who visited our hospital from March 2008 to January 2010 were subjected to this study. Their sex, age, modes of burn, degree, TBSA (%), ulcerated area, the time of occurrence of the ulcerations in the burn scars were investigated. In addition, radiological examination and biopsy was performed to diagnose heterotopic calcification. Results: Among the 14 cases, 6 were male and 8 were female. The average age of the patients was 48.2 (27 - 69 yrs). As for the mode of burn, 11 were flame burns and 3 were scalding burns. The average time of occurrence of the ulcerations in the burn scars was 4.5 months. The ulcerated areas were situated in the legs in 12 cases, arms in 1 case, and torso in 1 case. The diagnosis was confirmed through X-ray and biopsy, and skin graft was performed after wide excision. Conclusion: Diagnosis of the ulceration in burn scars accompanied by heterotopic calcification is possible through radiological and pathologic studies. Surgical treatment is the most reliable method of treatment, and we chose to perform skin graft after wide excision. Also, we learned that the complete removal of the calcified tissue and the inflammatory fibrotic tissues is crucial in preventing recurrence. Also, in contrast to Marjolin's ulcer, heterotopic calcification had a small size, little or no granulation tissue, and lacked fungating type ulceration. Therefore, favorable prognosis could be achieved through adequate treatment.

• Bangmulgwan gwa yeongu (The National Museum of Korea Journal)
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• v.1
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• pp.120-147
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• 2024

The inscribed bricks from the Tomb of Jang Mui are unique in many ways. First, there are nearly a hundred of them. Second, there are multiples bearing the same inscriptions. Third, their production methods, including type of firing, are diverse. Fourth, the forms of the bricks are inconsistent. Fifth, the positioning of the sides with inscriptions or stamped designs and those with no designs (as well as the vertical orientation of the inscriptions) are inconsistent. Sixth, most bricks bear inscriptions written reverseds. Seventh, white lime has been painted on the surfaces of the inscribed bricks. Despite these aspects, however, a comparison with Chinese inscribed bricks from the Weijin Dynasties reveals that the inscribed bricks from the Tomb of Jang Mui are indeed connected to their counterparts and provide important materials for forging a more holistic understanding of East Asian culture. Moreover, the understanding of the inscriptions as not just a series of Chinese characters, but as textual objects with characters stamped on them, a focus on how the inscribed bricks were placed inside the tomb, and the observation of them from viewers' perspectives can help clarify the significance of the inscribed bricks from the Tomb of Jang Mui.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.746-751
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• 2002

Fluidized bed combustion is a coal combustion technology that can reduce both SOx and NOx emission; SOx is removed by limestone that is fed into the combustion chamber and the NOx is reduced by low temperature combustion in a fluidized bed combustor and air stepping, but $N_2O$ generation is quite high. $N_2O$ is not only a greenhouse gas but also an agent of ozone destruction in the stratosphere. The calcium oxide(CaO) is known to be a catalyst of $N_2O$ decomposition. This study of $N_2O$ decomposition reaction in fixed bed reactor packed over CaO bed has been conducted. Effects of parameters such as concentration of inlet $N_2O$ gas, reaction temperature, CaO bed height and effect of $CO_2$, NO, $O_2$ gas on the decomposition reaction have been investigated. As a result of the experiment, it has been shown that $N_2O$ decomposition reaction increased with the increasing fixed bed temperature. While conversion of the reaction was decreased with increasing $CO_2$ concentration. Also, under the present of NO, the conversion of $N_2O$ decomposition is decreased. From the result of kinetic study gained the heterogeneous reaction rate on $N_2O$ decomposition. In the case of $N_2O$ decomposition over CaO, heterogeneous reaction rate is. $\frac{d[N_2O]}{dt}=\frac{3.86{\times}10^9{\exp}(-15841/R)K_{N_2O}[N_2O]}{(1+K_{N_2O}[N_2O]+K_{CO_2}[CO_2])}$. In this study, it is found that the calcium oxide is a good catalyst of $N_2O$ decomposition.