DSpace 集合:https://scholars.lib.ntu.edu.tw/handle/123456789/349372024-03-29T15:42:52Z2024-03-29T15:42:52ZMiniaturized ionogel-based bi-stable actuator with state-sensing capabilityLo, Li YuLin, Pei TingCho, Chia YuWang, Hsiang YunYAO-JOE YANGhttps://scholars.lib.ntu.edu.tw/handle/123456789/6414202024-03-27T03:35:11Z2024-05-01T00:00:00Z標題: Miniaturized ionogel-based bi-stable actuator with state-sensing capability
作者: Lo, Li Yu; Lin, Pei Ting; Cho, Chia Yu; Wang, Hsiang Yun; YAO-JOE YANG
摘要: This work reports a miniaturized actuator with state-sensing and bi-stable capabilities that was developed by utilizing the shape memory effect of ionogel. The actuator consists of a carbon nanotube (CNT) dispersed ionogel finger, a thermo-responsive liquid-crystal elastomer (LCE) cantilever, and a micromachined heater layer. The LCE cantilever serves as an actuating material for deforming the ionogel finger, while the heater layer is used to induce LCE deformation by elevating the LCE temperature. Due to the one-way shape memory effect, the ionogel finger possesses bistability with large deformations, and is capable of staying in either position without consuming energy. The ionogel finger also functions as a sensing material for detecting its state in a sensorless fashion. A bi-stable gripper constructed by assembling two proposed actuators was demonstrated and characterized. In addition, a video demonstration showed that the gripper could grasp and stably hold heavy metal objects without consuming any power because of its bistability.2024-05-01T00:00:00ZReplication of large-area microstructures by combining movable induction heating and roller hot embossingHung, Wei ChengChiu, Chun YangHe, Jyun WeiKe, Kun ChengSEN-YEU YANGhttps://scholars.lib.ntu.edu.tw/handle/123456789/6414192024-03-27T03:33:31Z2024-01-01T00:00:00Z標題: Replication of large-area microstructures by combining movable induction heating and roller hot embossing
作者: Hung, Wei Cheng; Chiu, Chun Yang; He, Jyun Wei; Ke, Kun Cheng; SEN-YEU YANG
摘要: Hot embossing is a low-cost and flexible method for fabricating microstructures and nanostructures on polymers. However, the conventional hot embossing process poses two challenges: First, the plates that are used do not provide uniform pressure, and the size of the chamber limits the imprinting area. Second, heating with thick metal plates significantly lengthens cycle time. Finally, the uniformity of temperature also affects the embossing results. To achieve a high heating rate and uniform pressure over a large area, this study combined an induction heating system and roll-to-plate hot embossing. A movable plate was used to move the mold through the induction coil, increasing the heating area and overcoming limitations related to the embossing area posed by the coil length. The imprinting area reached 100 × 100 mm2. In addition, the temperature difference was less than 20°C at each molding temperature range from 150°C to 190°C. The mold and the substrate were placed on a vacuum absorber to prevent deformation and slippage of the mold and provide preloading and packing pressure. Cooling fans were employed to improve cooling efficiency. Experimental replication yielded replication rates higher than 97% at 190°C and 5 kgf/cm2 with a cycle time of approximately 2 minutes. To verify the feasibility of the process, V-groove microstructures were successfully fabricated using a movable induction heating roller embossing facility. Highlights: The feasibility of the moving induction heating roller embossing process. A vacuum movable platform prevents deformation and slippage of the substrate. Improve the temperature uniformity of the movable platform.2024-01-01T00:00:00ZReaction Wheel Design for Precise Attitude Control of CubeSats Using Flexible PCB Windings and Halbach Magnet ArrayLiu, Nai WenHung, Kuo YuanLyu, Bo TingSHIH-CHIN YANGLin, Ying PoYu Chan, Chenhttps://scholars.lib.ntu.edu.tw/handle/123456789/6414132024-03-27T02:59:29Z2024-01-01T00:00:00Z標題: Reaction Wheel Design for Precise Attitude Control of CubeSats Using Flexible PCB Windings and Halbach Magnet Array
作者: Liu, Nai Wen; Hung, Kuo Yuan; Lyu, Bo Ting; SHIH-CHIN YANG; Lin, Ying Po; Yu Chan, Chen
摘要: This paper proposes a reaction wheel design for angular momentum control of CubeSats using flexible printed circuit board (FPCB) windings and Halbach magnet array. Reaction wheels must provide sufficient adjustable angular momentum under the weight and space restrictions in aerospace applications. The proposed wheel is based on a 3-phase permanent magnet synchronous motor (PMSM) with several features to minimize the weight. It consists of a coreless stator with FPCB windings and an outer rotor with a Halbach magnet array to maximize and smoothen the output torque. Different from conventional reaction wheels with only a single-layer outer rotor, this design features a dual-layer rotor composed of inner and outer yokes. Therefore, the magnetic force acting on the bearing due to the interaction between the stator yokes and the magnets can be eliminated. Besides, instead of the conventional dual-layer rotor with magnets attached to both yokes, the proposed design only has the magnets attached to the outer yoke. According to the FEA, the proposed dual-layer rotor shows better torque ripple reduction. The reaction wheel prototypes with conventional enameled copper winding and proposed FPCB windings are both fabricated for experimental comparison. According to the experiment results, the proposed reaction wheel using FPCB windings achieves comparable performance to a conventional reaction wheel with enameled copper windings. More importantly, the weight of the proposal is lighter, and the potting process for windings can be removed to increase the overall reliability.2024-01-01T00:00:00ZAn investigation into the thermal rectification in one-dimensional asymmetric systemsMEI-JIAU HUANGLiao, Hao Yuhttps://scholars.lib.ntu.edu.tw/handle/123456789/6414122024-03-27T02:57:49Z2024-05-15T00:00:00Z標題: An investigation into the thermal rectification in one-dimensional asymmetric systems
作者: MEI-JIAU HUANG; Liao, Hao Yu
摘要: The thermal rectification phenomenon in a one-dimensional asymmetric system of two thin films with different temperature-dependent thermal conductivities is studied. Based on the traditional thermal diffusion equation, the optimization condition for maximizing the thermal rectification ratio is re-examined; a new sufficient condition is found that the interface temperatures in the forward and reverse heat transfer directions should be equal, regardless of how the thermal conductivities depend on temperature. In other words, the thermal rectification ratio is maximized when the temperature dependence of the thermal conductivity over the entire operating temperature range is fully exploited. This sufficient condition can be used to find out the optimal geometric parameters of nanostructures which determine the effective thermal conductivity. An illustration of an asymmetric system composed of monolayer graphene sheet (GS) and graphene nanomesh (GNM) is presented. This study is beneficial to the development of thermal devices such as thermal resistors, thermal diodes, and thermal logic circuits.2024-05-15T00:00:00Z