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김두만,임경호,황재혁,이환규 한국항공대학교 1992 論文集 Vol.30 No.-
본 연구를 통하여 항공기 착륙장치의 거동(동특성 및 완충기 효율)을 해석하고 평가하는 Software를 개발하엿다. 이 프로그램을 개발하기 위해 착륙장치를 2개의 자유도를 가지는 동역학시스템으로 모델링하고 운동방정식을 유도하였다. 또한 완충기에 작용하는 내력(즉 공기력, orifice force, friction force)을 표현하는 관계식을 정립하였으며, 타이어의 힘을 표현하는 관계식을 유도하였다. 그리고 운동방정식에는 타이어의 Spin Up운동도 고려되었다. 선정된 항공기의 착륙장치의 Parameter의 값을 프로그램의 입력 Data로 사용했을 때 매우 신뢰할 만한 동특성의 결과를 얻었으며, 특히 Drop Test 결과와 본 연구에서 개발된 Software에서 얻어진 결과를 비교했을 때 매우 흡사한 결과를 얻었다. 따라서 본 연구에서 개발된 Software는 앞으로 국산화되는 착륙장치의 개발 및 설계에 매우 유용하게 사용될 것으로 판단된다. 또한 본 연구에서 사용된 입력 Data중 중요한 10개의 Parameter를 선정하여, 각 Parsmeter를 변화시키면서 착륙장치의 동특성 및 효율의 변화를 고찰해 보았다. 완충기 설계시 가장 중요한 Parameter들은 K-factor, Orifice 단면적 등과 같은 완충기의 변수로 사료되며, 타이어의 변수 T??이나 b는 중요한 변수가 아님을 확인하였다. 또한 항공기의 무게 W, Wheel/Tire의 무게, 완충기의 초기 공기압 P??, 항공역학계수 A도 착륙장치의 효율에는 크게 영향을 미치지 않고 있음을 고찰하였다. 그러나 공기실의 Politropic 지수 n, 항공기의 수직착륙속도 V는 착륙장치의 효융에 Non-Monotonic하게 영향을 미치는 것을 고찰하였다. The software which analysis and evaluate the dynamic characteristics of an landing gear has been developed in this study. The landing gear system has been modelled to be 2 DOF dynamic system to drive the equation of motion. The three internal forces, which are air pressure force, orifice force, and friction force, has been formulated and also the tire force has been formulated and also the tire force has been derived. When the typical values of the design parameters is applied to the developed software, the reliable results of the dynamic characteristics are obtained. Furthermore there is a good agreement between the simulation results and experimental drop test extracted from relevant literatures. It can be concluded that the developed software will be useful for the design and development of a landing gear system inside Korea.
이환규,김준영,김성룡,박진후,정휘동,정영수 대한치과의사협회 2022 대한치과의사협회지 Vol.60 No.10
Alveolar cleft is a congenital anomaly with a frequency of 0.18-2.50 per 1,000 births, which invades the bone of maxillary arch. Iliac crestal bone graft, considered as the gold standard for treatment of alveolar cleft, is a commonly used material due to its abundant mass, ease of harvesting, and the advantages of simultaneous operation with alveolar cleft reconstruction surgery. Despite many advantages of Iliac crestal bone graft, many studies have been conducted on alternative and additional materials for secondary alveolar bone graft in consideration of the disadvantages of iliac crest bone graft. Autogenous bone grafts from other donor sites, such as cranium, mandible and tibia can be used as an alternative with lower morbidity and lower bone resorption. Bone-tissue engineering strategies such as scaffolds, growth factors have also shown promising results in treatment of alveolar cleft. In addition, the use of Platelet-Rich-Fibrin/Plasma with abundant growth factors and osteoinducibility can increase bone maintenance and achieve better results. Therefore, here we review the various bone graft methods used in reconstruction of alveolar cleft.
약물전달 복합체와 지질 멤브레인 간의 상호작용에 관한 분자모델링
이환규 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
Molecular dynamics simulations of ionic liquids, PEGylated carbon nanotubes and antimicrobial peptides were simulated with lipid bilayers using all-atom and coarse-grained models. The following topics will be presented: (1) the binding and insertion of imidazolium-based ionic surfactants into lipid bilayers (2) the conformation of polyethylene glycol on carbon nanotube: mushroom-brush transition (3) synergistic effects of magainin 2 and PGLa on their heterodimer formation, aggregation, and insertion into the bilayer (4) the effects of PEGylation on the binding interaction of magainin 2 and tachyplesin I with lipid bilayer surface.
林炳五,李桓圭 弘益大學校 1982 弘大論叢 Vol.14 No.2
The sample used in the extraction of titanium dioxide was ilmenite. This ilmenite was mined from So-Yeonpeong-Do. The ilmenite was mixed with potassium tetraborate which was used as a solvent, and heated to a high temperature for the fused reaction. It was cooled down to room temperature. Then, potassium borates were extracted from this product by boiling water, and KFe???? Ti₃O?? by hot 0.5M-H₂SO₄. Through this reaction Ti??⁴ was extracted and TiO₂ was produced from the remaining raffinate. The reaction temperature and time were changed to find the optimum point. It was observed that the optimum time and temperature for the formation and the reaction were 45 minutes and 1050℃ respectively. Also unreacted potassium borates which were extracted by water and solidified after evaporation can be used as a solvent again. The recovery factor of the rutile was 78.2%.