https://oak.chosun.ac.kr/handle/2020.oak/19145 2025-08-19T03:32:00Z https://oak.chosun.ac.kr/handle/2020.oak/19335 Title: 수평저항력 보강 Pile의 말뚝지지력 특성 Author(s): 김대현; 정상국 Abstract: Although there have been many studies on pile foundations subjected to vertical load domestically and externally, the domestic studies on pile under horizontal load have been limited. The purpose of this study is to develop a pile, which allows the pile member and column member to overlap with each other, and the lateral load to be supported not only by a pillar member but also by pile member in order to address the problems above. The results of field load test showed that the horizontal resistance of pile is higher by 4-4.5 times compared to general ones. It was found that the improved horizontal resistance corresponds to the wing area of the upper fixed pile, suggesting that the resistance is proportional to the wing area. The 1/β depth should be considered for the reinforcement against horizontal force to a proper depth. 2018-12-31T15:00:00Z https://oak.chosun.ac.kr/handle/2020.oak/19337 Title: 고해상도 수치기법을 이용한 플래핑 날개 주위 비정상 아음속 유동해석 Author(s): 김익태; 김종록; 이경환; 김재수 Abstract: Many numerical and experimental researches have been done for the unsteady flow around a flapping airfoil. The main research topics are vortex shedding, dynamic stall phenomenon, and MAV's lift and thrust generation for the flow over a flapping airfoil. Although many researches have been studied to analyze the flow for the variation of frequency and amplitude, much research is still needed. In this study, thrust generation, wake structures, and acoustic wave propagation characteristics were studied for a flapping airfoil. The governing equation was the Navier-Stokes equation with LES turbulence model, and the Optimized High-Order Compact (OHOC) scheme and 4th order Runge-Kutta method were used. The Mach number and Reynolds number were 0.3 and 1000, respectively. The analysis of mean lift and drag coefficients showed the thrust generation characteristics according to the phase angle and the reduced frequency. The wake vortex shedding and propagation characteristics of acoustic waves could be simulated using the high order method. 2018-12-31T15:00:00Z https://oak.chosun.ac.kr/handle/2020.oak/19334 Title: 마이크로중력 비행 실험을 위한 연소실험장비의 구조해석 Author(s): 이종원; 홍터기; 남원식; 이주희; 김연규; 박설현 Abstract: This study had developed a combustion experiment system for a cool flame research in microgravity environment. For the development of the system, various combustion experiment devices used on the ISS were reviewed, and the shape, size, thickness, and material of the combustion chamber were designed by the standard requirements based on the Korea Standard (KS) and Japan Industrial Standard (JIS). The system was loaded on a reduced-gravity aircraft (so-called, parabolic flight campaign) at Zero-G Corporation in the United States for the cool flame experiment. For the experiment in the aircraft which simulated microgravity environment, structural analysis of a combustion chamber under the condition of pressurized and depressurized cases using a finite elements method was carried out. Furthermore, the factor of safety for the combustion system in the aircraft where hyper-gravity (9G) occurred was calculated. It was confirmed that the system was structurally safe for parabolic flight experiment under microgravity. 2018-12-31T15:00:00Z https://oak.chosun.ac.kr/handle/2020.oak/19336 Title: 담색국화잎지의류 추출물의 폴리페놀, 플라보노이드 함량 및 항산화 활성 탐색 Author(s): 문승재 Abstract: Lichens are complex microorganisms in which fungi (mycobionts) and algae (photobionts) live in symbiosis by forming limbs. Most of the fungi that make up lichens, such as the Burleighi, are asymptomatic fungi, accounting for almost 99% of all known lichen species. In this study, polyphenol content, flavoid content, and antioxidant activity were investigated to inquire the possibility of Xanthoparmelia meximcana as a cosmetic material. Total polyphenol contents were calculated to be 500 μg/mL and four antioxidant assays whereas DPPH, ABTS, and hydroxyl radical scavenging were performed resulting in the range of 50-500 μg/mL (IC50). All four fractions showed no cytotoxicity up to the concentration of 100 μg/mL by MTT assay. The Xanthoparmelia meximcana would be a valuable asset for many applications, including cosmetic products. 2018-12-31T15:00:00Z