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티타늄 이소프로폭사이드를 이용한 졸-겔법에 의한 TiN 코팅 cBN 분말 합성
이윤성,김선욱,이영진,이지선,신동욱,김세훈,김진호,Lee, Youn Seong,Kim, Sun Woog,Lee, Young Jin,Lee, Ji Sun,Shin, Dongwook,Kim, Sae-Hoon,Kim, Jin Ho 한국전기전자재료학회 2020 전기전자재료학회논문지 Vol.33 No.5
In this study, TiN-coated cBN (cubic-structure boron nitride) powders were successfully synthesized by a sol-gel method using titanium (IV) isopropoxide (TTIP) and by controlling the heat treatment conditions. After the sol-gel process, amorphous nano-sized TiO<sub>x</sub> was uniformly coated on the surface of cBN powder particles. The obtained TiO<sub>x</sub>-coated cBN powders were heated at 1,000~1,300℃ for 1 or 6 h in a flow of 95%N<sub>2</sub>-5%H<sub>2</sub> mixed gas. With increasing temperature, the chemical composition of the TiO<sub>x</sub> coating layer changed in the order of TiO<sub>2</sub>→Ti<sub>6</sub>O<sub>11</sub>→Ti<sub>4</sub>O<sub>7</sub>→TiN due to reduction of the Ti ions. The TiN coating layer was observable in the samples heated at 1,200℃ and appeared as the main phase in the sample heated at 1,300℃. The resulting thickness of the TiN coating layer of the sample heated at 1,300℃ was approximately 45~50 nm.
이윤성,이상수,송하영,배기선,이성복,이도헌,Lee, Yun-Seong,Lee, Sang-Soo,Song, Ha-Young,Bae, Kee-Sun,Lee, Sung-Bok,Lee, Do-Heun 한국토지주택공사 토지주택연구원 2010 LHI journal of land, housing, and urban affairs Vol.1 No.1
하수도관 정비사업 및 정부의 4대강 사업에서 발생되는 준설모래는 대부분 투기 및 매립에 의존하여 처리되고 있다. 이는 준설모래를 적절히 이용하는 관련 재활용 기술의 부족과 기존의 준설모래 생산시스템에서 생산된 준설모래의 높은 흡수율과 미립분 함유량에서 비롯된다. 따라서 본 연구에서는 기존의 준설모래 생산시스템의 문제점을 보완한 최적의 세척선별시스템을 통해, 준설모래 품질개선 성능과 세척선별시스템의 미립분과 유기이물질 제거 성능을 알아보기 위한 연구의 일환으로서, 처리된 준설모래의 기초물성을 평가한 결과, 세척선별시스템을 통해 생산된 준설모래가 흡수율, 0.08 mm체 통과량, 점토덩어리량, 유기이물질 함유량에서 큰 폭의 품질개선효과를 나타냈으며, 본 연구에서 목표로 하는 품질기준인 KS F 2573(콘크리트용 순환골재)과 KS F 2526(콘크리트용 골재) 기준에 모두 만족하는 것으로 나타나 향후 콘크리트용 골재로서의 활용가능성을 확인할 수 있었다. Most of the dredged sand generated from the sewage pipe maintenance project and the government's four-river project are disposed depending on abandonment and filling-up. This is caused by the lack of related recycling technology using dredged sand appropriately and high absorption rate and micro-particles of dredged sand producted from existing sand production system. Thus, this study carried out a quality assessment for the dredged sand produced through the optimum washing and sorting system supplementing problems of existing dredged sand production system as a part of research to examine performance of removing micro-particles and foreign substances. As a result of the assessment, the dredged sand produced through the cleaning and sorting system showed a wide quality improvement effect in absorption rate, 0.08 mm sieve pass amount, clay lump volume and organic impurity content, and it turned out to satisfy both the quality standards of this study, KS F 2573(recycled aggregate for concrete) and KS F 2526(aggregate for concrete) so it could be confirmed that it would be able to be used as an aggregate for concrete in the future.
이윤성,Lee, Yoon Seong 연세대학교 의과대학 2016 의학교육논단 Vol.18 No.1
Although the state of medicine in North Korea is of great interest, there is little information, if any, about the present state of medicine in North Korea. Even North Korea's laws and regulations on medicine are not publicly available. It is plausible that the dictator's commands or the policy of the Communist Party may be superior to the nation's constitution and laws on medical education and much more. Information is only available from a limited number of publications and mainly from the statements of refugees, which differ greatly among themselves. No one refugee could provide authoritative data or information because they were never in the position to see the larger picture or have experience over the long term. However, what is known is that the major health professions in North Korea include physicians (medical doctors), stomatologists (oral doctors), 'Koryo' doctors (doctors of Korean traditional medicine), midwives, and nurses. The names and the founding year of each of the regular medical schools are listed along with the change and restoration of names of schools. It is known that there have been quasi-physicians and semi-physicians. However, the reasons for any changes that have taken place also remain unknown. The educational system, curriculum, and even the number of years of training needed to qualify to become a physician have varied from time to time.
화학적 합성법에 의한 금속수소화물의 제조 및 수소화 속도론적 연구
이윤성,오재완,문성식,남기석 ( Yun Sung Lee,Jae Wan Oh,Sung Sik Moon,Kee Suk Nahm ) 한국공업화학회 1998 공업화학 Vol.9 No.2
금속수소화물 LaNi_5와 LaNi_(4.5)Al_(0.5)을 화학적 합성법으로 제조하여, 합성된 금속수소화물의 물성을 다양한 방법으로 확인하였다. LaNi_5와 LaNi_(4.5)Al_(0.5)은 2회 정도 수소화/탈수소화 반응을 시키면 활성화되었으며, 압력-농도-온도 곡선을 측정한 결과 각각 6개와 5.5개의 수소원자가 저장되었다. LaNi_(4.5)Al_(0.5)의 경우 수소화 반응속도를 초기속도법으로 구한 결과 비반응 수축핵모델이 잘 적용되었으며, 수소화반응의 을속단계는 LaNi_(4.5)Al_(0.5)의 표면에서 수소분자의 해리화학흡착임을 알 수 있었다. LaNi_(4.5)Al_(0.5)의 수소화반응 활성화에너지는 9.506 kcal/㏖-H₂이었으며, 반응속도식은 273∼343K와 P_0-P_(eq) = 0.25∼0.66 atm의 범위에서 아래와 같이 표시되었다. dX/dt = 4.636(P_0 - P_(eq)) exp (-9506/RT) Metal hydrides, LaNi_5 and LaNi_(4.5)Al_(0.5), were prepared using chemical synthetic method, and their physical properties were examined using various analytic techniques such as TGA, XRD, SEM, and EDX. The activation of the chemically prepared LaNi_5 and LaNi_(4.5)Al_(0.5) was achieved by twc hydriding/dehydriding cycles only. The measurements of P-C-T curves revealed that 6 and 5.5 hydrogen atoms were stored in LaNi_5 and LaNi_(4.5)Al_(0.5) respectively. The hydriding reaction rates for LaNi_(4.5)Al_(0.5) were measured by the method of initial rates. It was found that the shrinking unreacted core model could be applied for the analysis of hydriding kinetics of LaNi_(4.5)Al_(0.5). The rate controlling step of this reaction was the dissociative chemisorption of hydrogen molecules on the surface of LaNi_(4.5)Al_(0.5). The activation energy was 9.506kcal/mol-Hz. The rates measured in the temperature range from 273 to 343 K and in the pressure difference (P_0 - P_(eq)) range from 0.25 to 0.66 atm could be expressed as the following equation ; dX/dt = 4.636(P_0 - P_(eq)) exp (-9506/RT)