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Calcium sulfate-Hydroxyapatite 혼합재의 물성 및 치근천공 치유효과에 관한 연구
이승종,김경남,Lee, Seung-Jong,Kim, Kyoung-Nam 대한치과보존학회 1997 Restorative Dentistry & Endodontics Vol.22 No.2
Treatment of root perforation elicits special considerations due to its blood-contaminated circumstances. It is known that conventional dental restorative materials are all leaking. Calcium sulfate is the material which react with water to become chemically set. This study, therefore, was performed to develop a new compound containing calcium sulfate and to evaluate its physical and biological characteristics. Three materials were used, IRM, calcium sulfate, calcium sulfate-hydroxyapatite compound. The composition of the calcium sulfate-hydroxyapatite compound was basically 50 % of calcium sulfate and 50 % of hydroxyapatite mixed with guajacol. The materials were mixed in conventional way and underwent four physical test procedures, setting time, solubility test, compressive strength, and marginal leakage test. All materials were evaluated under the scanning electron microscope to examine the marginal sealing ability. Animal experiment was also performed to test the materials' tissue response. Twenty-four dog's premolars were tested with either furcation perforations or apical retro-fillings. From the results, we found that calcium sulfate possess the good marginal sealing ability. However, calcium sulfate creates many voids which is caused by crystal thrusting action when it reacts with water. It seemed that the voids caused disintegration of the material which eventually lead to tissue reaction. By compounding calcium sulfate and hydroxyapatite, we were able to obtain the better physical properties but it showed larger marginal gap between the material and the root surface. Within the six weeks observation period, both IRM and calcium sulfate-hydroxyapatite compound showed good tissue responses in animal experiment. It is concluded that calcium sulfate would be the material of choice in root perforation repair, but the physical property needs to be further improved.
제주도 신산 연안 정치망 어획물의 종조성 및 어획량 변동
이승종 ( Seung-jong Lee ),한송헌 ( Song-heon Han ),김맹진 ( Maeng-jin Kim ) 한국수산해양기술학회(구 한국어업기술학회) 2021 수산해양기술연구 Vol.57 No.1
Species composition and variation of catches in the coastal waters of Sinsan of Jeju Island were determined using samples collected by a set net from May 2014 to October 2015. During the survey period, a total of 55 species (51 species, 35 families and 11 orders in fishes, 4 species, 2 families and 2 orders in cephalopods) were occurred, and Perciformes (28 species) were dominant fishes in this area. In the number of individuals and biomass, the small pelagic fishes such as Trachurus japonicus and Scomber japonicus were occurred abundantly, and both species accounted for 95.9% of the total catch by a fishing logbook of a set net. In the results of length-frequency distribution of small pelagic fishes caught by a set net in Sinsan, T. japonicus showed a range from 3.5-19.1 cm (average 8.8 cm) and S. japonicus showed a range from 7.0-25.6 cm (average 16.8 cm). In addition, these were mostly immature fishes.
고온 건식 정제시스템 적용을 위한 Pilot급 석탄가스화기의 운전특성
이승종(Lee, Seung Jong),유상오(Yoo, Sang Oh),정우현(Jung, Woo Hyun),정석우(Chung, Seok Woo),윤용승(Yun, Yongseung) 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.11
자원고갈과 지구온난화 등으로 재생에너지의 사용 및 보급이 지속적으로 증가할 것으로 예상되지만, 세계적으로 매장량이 풍부한 석탄의 사용량은 2030년 이후에도 지속적으로 증가될 전망이다. 따라서 세계 각국은 기후변화 규제에 대응하면서도 청정하게 석탄을 사용하기 위한 기술의 개발 및 보급을 활발히 진행 중이며, 국내에서도 온실가스 감축과 동시에 국가 성장 동력화를 추진하고 있다. 석탄가스화 기술은 석탄을 가스화하여 생산된 CO, H₂가 주성분인 합성가스를 연료로 활용하는 기술로, 이용 효율이 높고 석탄을 천연가스 수준으로 청정하게 사용할 수 있는 차세대 석탄이용 기술이다. 본 연구에서는 pilot급 석탄 가스화기에서 생산된 합성가스에 함유된 산성가스를 고온에서 건식으로 제거하는 시스템을 구축하였으며, 석탄 합성가스를 고온 건식 정제시스템에 공급하기 위한 석탄가스화기의 운전특성을 파악하였다.
이승종(Lee, Seung-Jong),황상연(Hwang, Sang-Yeon),유영돈(Yoo, Young-Don),윤용승(Yun, Yong-Seung) 한국신재생에너지학회 2007 한국신재생에너지학회 학술대회논문집 Vol.2007 No.06
The acid gas removal (AGR) system was designed and installed to remove H₂S in coal syngas in the pilot-scale coal gasification system for producing chemicals like Dimethyl Ether(DME). The syngas from the coal gasification at the rate of 100{sim120 Nm³/hr included pollutants such as fly ash. H₂S, COS, NH₃, etc. The designed temperature and pressure of the AGR system are below 50oC and 8 kg/cm². Fe-chelate was used as an absorbent. H₂S was stably removed below 0.5 ppm in the AGR system when the concentration of H₂S was 150{sim}450 ppm. The pH of Fe-chelate solution was also stably maintained between 8{sim}9. FeMgO absorbent was also tested to remove H₂S in the lab-scale AGR system and H₂S was also removed below 0.5 ppm in the initial operation.