https://oak.chosun.ac.kr/handle/2020.oak/19142 2026-05-21T21:51:09Z 2026-05-21T21:51:09Z 우민홍 김주민 차지혜 정호영 장덕례 https://oak.chosun.ac.kr/handle/2020.oak/19310 2024-05-13T07:26:47Z 2018-12-31T15:00:00Z

Title: 전고체 리튬이차전지의 PEO/LLZO 복합고체전해질 특성 Author(s): 우민홍; 김주민; 차지혜; 정호영; 장덕례 Abstract: The PEO/LLZO solid composite electrolyte with high ionic conductivity and low interfacial resistance was prepared by solution casting method. The electrochemical properties such as lithium ion conductivity, lithium ion transference number, electrochemical stability and compatability with lithium metal anode of PEO/LLZO solid composite electrolyte were investigated. The results showed that the addition of LLZO could effectively improve the ionic conductivity, electrochemical stability window, transference number, and compatibility with lithium metal of composite electrolytes. The LLZO 45% content of the PEO/LLZO solid composite electrolyte showed the lowest activation energy and the electrochemical stability at 4.75V (vs Li/Li+). In addition, when the thickness of the PEO/LLZO solid composite electrolyte was 130 μm or more, The behavior of Li+ plating/stripping on lithium symmetric cell was greatly enhanced. The NCM622/Li solid-state lithium ion battery assembled with the PEO/LLZO solid composite electrolytes had good cycling performance. At current rate of 0.5C, the discharge specific capacity remained about 148mAh/g after 100cycles at 60℃.

2018-12-31T15:00:00Z 김성환 최병기 양동희 https://oak.chosun.ac.kr/handle/2020.oak/19311 2024-05-13T07:26:47Z 2018-12-31T15:00:00Z

Title: 안테나 결합형 수직 풍력터빈의 에어포일 분석에 관한 연구 Author(s): 김성환; 최병기; 양동희 Abstract: In this paper, we design and verify a system that combines a mobile communication base station antenna with a vertical wind turbine. The airfoil shape of the straight blade was applied to NACA0012, NACA0015, and NACA0018. The performance was verified by computational fluid dynamics using the k-epsilon turbulent model of ANSYS CFX. We calculated torque by CFD calculation and predicted power output. The performance of the wind turbine and the torque and power output when the antenna was added were compared. Steady analysis was performed at wind speed of 6 ~ 12 m/s and 100 ~ 500 rpm. NACA0018 is high when the rotation speed is low, and NACA0012 is high when the rotation speed is low. Overall performance is highest when NACA0018 is applied.

2018-12-31T15:00:00Z 송신형 https://oak.chosun.ac.kr/handle/2020.oak/19313 2024-05-13T07:26:47Z 2018-12-31T15:00:00Z

Title: Deep Neural Network와 Support Vector Regression을 이용한 인콜로이 825의 고온변형 연구 Author(s): 송신형 Abstract: Incology825 is a nickel-based alloy with good corrosion resistance as well as heat resistance. For effective application of Incoloy825, the flow behavior of the Incoloy 825 during hot deformation needs to be studied and the efficient flow model developed. In this study, hot deformation test was carried out under the temperature of 925℃, 1050℃ and 1150℃ and strain rate of 0.003/s and 3/s. Deep neural network and support vector regression algorithm was thereafter used to model the flow behavior of Incoloy825. The research found that both algorithms describes the flow stress of incoloy825 well. Comparison between deep neural network and support vector regression was done.

2018-12-31T15:00:00Z 서혁 김대현 https://oak.chosun.ac.kr/handle/2020.oak/19312 2024-05-13T07:26:47Z 2018-12-31T15:00:00Z

Title: 모래의 입도분포와 세립분 함유량에 따른 액상화 저항특성 비교 Author(s): 서혁; 김대현 Abstract: he liquefaction phenomenon occurs when the groundwater is pumped up through the top of sediments as the pore pressure increases due to the earthquake. There have been many studies on the loose sandy soils and various samples through repeated triaxial compression tests and shaking table tests, but there have been few studies on the effects of particle size distributions and the fine contents of sand on the liquefaction of sand. In this study, the undrained repeated triaxial compression tests were performed on sands with different particle size distributions, confining pressures, relative densities, and deviatoric stresses. The results of analysis showed that, with increasing relative density, SW(Well-graded sand) samples had higher liquefaction strength than SP(Poor-graded sand) samples. This is due to the lower void ratio of sand in SW samples than in SP samples. It was also found that the liquefaction strength decreased with a high fine content due to he rapid destruction of the filling of fine particles between the soil particles, leading to lower liquefaction strength.

2018-12-31T15:00:00Z