• Journal of Korean Tunnelling and Underground Space Association
• /
• v.19 no.3
• /
• pp.389-407
• /
• 2017

In the current work, a series of three-dimensional finite element analysis was carried out to understand the behaviour of pile when the tunnel passes through the lower part of a single pile or group piles. At the current study, the numerical analysis analysed the results regarding the ground reinforcement condition between the tunnel and pile foundation. In the numerical modelling, several key issues, such as the pile settlements, the axial pile forces, the shear stresses and the total displacements near the tunnel have been thoroughly analysed. The pile head settlements of the single pile with the maximum level of reinforcement decreased by about 16% compared to the pile without ground reinforcement. Furthermore, the maximum axial force of the single pile with the maximum level of ground reinforcement experienced a 30% reduction compared to the pile without reinforcement. It has been found that the angle of ground reinforcement in the transverse direction affects the pile behaviour more so than the length of the ground reinforcement in the longitudinal direction. On the other hand, in the case of the pile group with the reinforced pile cap, the ground displacement near the pile tip appears to be similar to the corresponding ground displacement without reinforcement. However, it was found that the pile cap near the pile head greatly restrained the pile head movement and hence the axial pile force increased by about 2.5 times near the pile top compared to the piles in other analysis conditions. The behaviour of the single pile and group piles, depending on the amount of ground reinforcement, has been extensively examined and analysed by considering the key features in great details.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.11
• /
• pp.690-696
• /
• 2017

Various types of alternative energy sources to petroleum are being developed both domestically and internationally as clean energy that does not emit greenhouse gases. In particular, offshore wind power has been studied because the wind resources are relatively limitless and the wind power is relatively smaller than onshore. In this study, to analyze the scour phenomenon around offshore wind foundations, mono pile and tripod pile foundations were simulated using a FLOW-3D model. The scour phenomenon was evaluated for mono piles: one is a pile with a 5 m diameter and d=1.69 m and the other is a pile with a 5 m diameter. Numerical analysis showed that in the latter, the falling-flow increased and the maximum scour depth occurred more than 1.7 times. For a tripod pile foundation, the measured velocity and the maximum wave condition were applied to the upstream boundary condition, respectively, and the scour phenomenon was evaluated. When the maximum wave condition was applied, the maximum scour depth occurred more than about 1.3 times. When the LES model was applied, the scour depth reached equilibrium, whereas the numerical results of the RNG model show that the scour phenomenon occurred in the entire boundary area and the scour depth did not reach equilibrium. To evaluate the scour phenomenon around offshore wind foundations, it is reasonable to apply the wave condition and the LES turbulence model to numerical model applications.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.9
• /
• pp.20-28
• /
• 2019

This study comparatively analyzes general walking shoes on the conical top foundation of the ground condition and the pressure distribution during walking with shoes that are currently under development. Two categories of footwear were used: general footwear and a footwear conical top foundation that is currently under development. Experiments were carried out on hard ground and sandy soil in 15 male twenties that satisfy the conditions of normal foot wearing 260 mm. The pressure during walking was measured using Techstorm's Wireless Insole System, and foot pressure was measured in 7 zones of the foot. Studies have shown different maximum forces, average pressures, and pressure distributions depending on the shoe and ground conditions. This study shows that shoes with general low pressure dispersion effects depending on the feet in hard ground and sand ground are different from shoes with the conical top foundation that is currently under development. It is expected that it will be useful for the development of shoes that can be worn in all hard ground and sandy ground by selecting various rubber materials through further research.

• Korean Journal of Environmental Biology
• /
• v.41 no.4
• /
• pp.463-472
• /
• 2023

The insecticidal activities of 27 different commercial products with environmentally friendly organic material(EFOM) against Scotinophara lurida, a major rice pest, were evaluated in the laboratory using spraying methods on plants and insects. Seven plant-derived organic farming materials (EFOM-8, -10, -12, -13, -19, -20, and -26) with high insecticidal effects when sprayed directly on the insect's body rather than on the plant were selected. In the indoor rice pot test, all 7 EFOMs showed an insecticidal rate of over 73.3% under flooding conditions. Notably, EFOM-13 and EFOM-20 demonstrated much higher insecticidal rates, ranging from 1.5 to 1.8 times, in flooding conditions compared to drained conditions. In the semi-paddy field test, EFOM-10 (80% garlic extract), EFOM-13 (62% neem extract), and EFOM-26 (70% sophora extract+28% ethyl alcohol+2% pyrethrum extract) exhibited a higher control value of 88.9% in the irrigated paddy on the 7th day, surpassing the control values in the drained paddy by 1.4 to 1.9 times. The control value in the irrigated rice paddy field sprayed with EFOM-10 reached 86.2% on the 7th day, which was 1.4 times higher than 61.9% in the drained paddy. Taken together, the findings suggest that direct contact of the insect's body with sufficient amounts of spray solution and the maintenance of paddy irrigation can enhance the controlling effect of EFOMs. These findings will be valuable in developing an optimal S. lurida control strategy for application in rice paddy fields in the near future.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2001.10a
• /
• pp.50-54
• /
• 2001

미래의 해전은, 현재와 같은 추세로 살펴본다면 무기 체계의 첨단 기술이 개발이 되었을 경우, 미사일 전쟁화가 될 것으로 추정이 된다. 본 연구에서는 현재 미 해군이 차세대 구축함으로 개발하고 있는 DD2l함을 근거로 해서 전투효율과 경제성에 기초를 둔, 차세대 함정이 갖추어야 할 필요 충분 조건이 무엇인가를 고찰하기로 하였다. 하나의 임무를 갖춘 함정의 여러 척수와 다종 임무를 갖춘 한 척의 함정간의 전투 효율과 경제성에 대한 비교로 부터, 다종 임무를 갖춘 한 척이 양측면에서 우수하다는 사실이 전술과 전략 측면에 관한 각종 연구를 통해 평가되고 있다.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 1975.12a
• /
• pp.181.4-181
• /
• 1975

유포자 젖산균 Bacillus sp의 식품이용을 위한 기초로서 유포자 젖산균의 발육, 포자형성 등에 관하여 연구한 결과는 다음과 같다. 탄수화물 중 dextrin이 좋았고, Mn, Ca ion, biotin 등은 생육, 포자형성, 내열성에 대하여 효과가 좋았다. 배양의 최적조건은 호기조건하에서 $37~45^{\circ}C에서$ 36시간 이상 배양하는 것이었다.

• Proceedings of the KIEE Conference
• /
• 2003.11b
• /
• pp.219-222
• /
• 2003

본 논문에서는 주어진 자동화 시스템에 대하여 Critical Path 기법을 적용한 최적화 연구를 수행하였다. 탄약 운반 자동화 시스템에 대하여 공정순서와 시간개념이 들어간 Timed Petri-Net을 이용한 이산사건 공정모델을 구축하였으며, 이를 기초로 초기조건 및 제약조건을 고려하여 제악탐색기법을 이용하여 Critical Path를 찾고 여유 공정을 산출항으로써 공정 시간 최적화를 수행하였다.

• Proceedings of the KAIS Fall Conference
• /
• 2010.11a
• /
• pp.356-358
• /
• 2010

Cuprous oxide ($Cu_2O$)를 기초로 하여 산화 박막 트랜지스터에 대하여 연구를 하였다. 일정한 두께의 cuprous oxide ($Cu_2O$) 박막을 조건별로 열처리 공정을 하고 그에 따른 변화를 측정을 하였다. 그 측정한 결과 중 가장 좋은 열처리 조건으로 열 증착 방식(Vacuum Thermal Evaporation)을 사용하여 cuprous oxide ($Cu_2O$) 비정질 산화 박막 트랜지스터를 제작 및 측정했다.

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 1992.12a
• /
• pp.25-26
• /
• 1992

식물공장에서 식물생산에 중요한 요인의 하나가 최적 양액과 배지조건이다. 세계적으로 식물공장은 완전한 수경지배시설을 갖추고 있으나 우리나라는 아직 초기단계에 있어 여러가지 기초연구가 부족한 실정이다. 그러므로 우리의 현실에 알맞은 조건을 찾아내어 실용화하기 위한 연구과정의 하나로 수경재배시의 배지와 양액종류에 따른 엽채류의 생육을 살펴보고자 한다. (중략)

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1998.10a
• /
• pp.13-13
• /
• 1998

램가속기의 발진 과정에서 유동장 내에는 수백 기압 이상의 고압 영역이 존재하며 이러한 영역에서는 이상기체 가정이 더 이상 유효하지 않게 된다. 따라서 램가속기 작동조건에 적용 가능한 적절한 형태의 실제 기체 상태 방정식이 요구된다 또한 기존의 온도에 종속적인 Arrhenius 형태의 기초 반응들로 이루어진 축소 화학 반응 모델은 상압 조건하에서 적용 가능하므로 고압 화경에서 적용하기 위해서는 온도뿐 아니라 압력에 종속적인 형태의 반응율 상수가 도입되어야 한다.