https://scholar.gist.ac.kr/handle/local/7921 2026-08-07T06:53:53Z 2026-08-07T06:53:53Z 정훈일 정지훈 이동선 C. J. Stanton 조영달 https://scholar.gist.ac.kr/handle/local/25158 2025-07-02T06:35:28Z 2010-01-21T15:00:00Z

Title: 나노 단위의 압전전기장 조절을 통한 테라파 발진과 주파수 조절 Author(s): 정훈일; 정지훈; 이동선; C. J. Stanton; 조영달

2010-01-21T15:00:00Z Lee, Donggun Choi, Seongim S. Chao, Yi Park, Jong-chun https://scholar.gist.ac.kr/handle/local/32429 2025-12-23T05:05:09Z 2025-01-09T15:00:00Z

Title: Wing Shape Optimization of Underwater Floats with Motion Constraints Author(s): Lee, Donggun; Choi, Seongim S.; Chao, Yi; Park, Jong-chun Abstract: This study investigates the effects of attaching wing shapes to the body of an underwater float, comparing its motion with and without wings. The body is limited to vertical motion. However, with wings attached, it can achieve horizontal and rotational movements, such as sawtooth and spiraling motions. These wings are effective in controlling the motion of the float in response to water flow and reducing drag. To design the wing airfoil shapes for the underwater float, we utilized a Conditional Deep Convolutional Generative Adversarial Network(DCGAN) model to achieve inverse design with high lift-to-drag ratios and lift coefficients. This model extends the basic GAN structure by adding conditions to the inputs of the generator and discriminator, enabling the generation of airfoil shapes with desired aerodynamic performance. Prior to planform optimization, aerodynamic coefficients were compared using a baseline shape for five candidate wing attachment positions. A total of 77 shapes were generated by varying the span and chord parameters within a ±23% range of the baseline values. These shapes were used to train a Gaussian Process Regression (GPR) model, which served as a surrogate model during the optimization process. Dynamic analysis was conducted at an underwater float angle of 35.5° to determine the objective function and constraints. Finally, planform optimization was performed using a Genetic Algorithm (GA). The results demonstrate the potential of wings to enhance the motion control and drag reduction of underwater floats, offering significant improvements in hydrodynamic performance. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

2025-01-09T15:00:00Z Yoon, Hoon Hahn Ahmed, Faisal Fernandez, Henry A. Nigmatulin, Fedor Cui, Xiaoqi Uddin, Md Gius Liapis, Andreas C. Cai, Weiwei Yang, Zongyin Hakonen, Pertti Lipsanen, Harri Hassan, Tawfique Sun, Zhipei https://scholar.gist.ac.kr/handle/local/34083 2026-07-24T05:05:10Z 2023-05-06T15:00:00Z

Title: Ultra-miniaturized Optical Spectrometers with a Highly Tunable van der Waals Junction Author(s): Yoon, Hoon Hahn; Ahmed, Faisal; Fernandez, Henry A.; Nigmatulin, Fedor; Cui, Xiaoqi; Uddin, Md Gius; Liapis, Andreas C.; Cai, Weiwei; Yang, Zongyin; Hakonen, Pertti; Lipsanen, Harri; Hassan, Tawfique; Sun, Zhipei Abstract: We report ultra-miniaturized (~10×20 μm2) spectrometers with electrically modulated van der Waals junctions in conjunction with a reconstruction algorithm, achieving spectral reconstruction with a spectral resolution of ~3-nm over a broad operation bandwidth for spectral imaging. © Optica Publishing Group 2023.

2023-05-06T15:00:00Z Yoon, Seon-Mi Kim, Sung Jin Shin, Hyeon-Jin Benayad, Anass Kim, Jong Min Lee, Young Hee Choi, Jae-Young https://scholar.gist.ac.kr/handle/local/34103 2026-07-24T05:05:12Z 2009-11-30T15:00:00Z

Title: Tailoring conductivity of carbon nanotubes network by halogen oxoanions Author(s): Yoon, Seon-Mi; Kim, Sung Jin; Shin, Hyeon-Jin; Benayad, Anass; Kim, Jong Min; Lee, Young Hee; Choi, Jae-Young Abstract: Chlorine oxoanions with the chlorine atom at different oxidation states were introduced in an attempt to systematically tailor the electronic structures of single-walled carbon nanotubes (SWCNTs). The degree of selective oxidation was controlled systematically by the different oxidation state of the chlorine oxoanion. Selective suppression of the metallic SWCNTs with a minimal effect on the semiconducting SWCNTs was observed at a high oxidation state. The adsorption behavior and charge transfer at a low oxidation state were in contrast to that observed at a high oxidation state. These results concurred with the experimental observations from X-ray photoelectron spectroscopy. The conversion of metallic SWCNTs to semiconducting ones at high oxidation state might result in an increase in the resistance of the intrinsic SWCNTs but reduces the contact resistance significantly by decreasing the number of metal-semiconductor junctions. The sheet resistance of the SWCNT film decreased significantly at high oxidation states, which was explained in terms of a p-doping phenomenon that is controlled by the oxidation state. © 2009 Materials Research Society.

2009-11-30T15:00:00Z