Browsing by Author "Cheng, Chih-Cheng"

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A Miniature Magnetic-Piezoelectric Thermal Energy Harvester
(2015-07-01)
Chen, Chin-Chung
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Chung, Tien-Kan
;
Tseng, Chia-Yuan
;
Hung, Chiao-Fang
;
Yeh, Po-Chen
In this paper, we report a miniature thermal energy harvester with a novel magnetic-piezoelectric design. The harvester consists of a soft magnetic Gd cantilever beam, a piezoelectric lead zirconate titanate sheet, an NdFeB hard magnet, silicon clamps, and a silicon frame. In this design, the harvester is driven by a temperature difference between a cold side and room temperature ambient air, unlike other magnetic-piezoelectric thermal energy harvesters that are driven by a temperature difference between a cold side and a hot side or between two hot sides. Experimental results show that with a temperature difference of 20 degrees C (cold side: 6.7 degrees C, hot side: 26.7 degrees C), the harvester produces a maximum peak-to-peak voltage of 37 mV and a root mean square voltage of 1.98 mV. The estimated maximum instantaneous power density and average power density is 21.7 nW/cm(3) and 62.9 pW/cm(3), respectively. Moreover, the total volume of our harvester (length x width x height: 6 x 3.5 x 3 mm) is 217 times lower than that of previous experimental harvesters and 38 times smaller than that of previous theoretical-modeled harvesters. Therefore, our harvester is the smallest machined magnetic-piezoelectric thermal energy harvester designed to date. These features enable our harvester to be more easily implemented and integrated with micro wireless sensors and thereby increase more self-powered wireless-sensing applications.
A NOVEL MECHANICAL-MECHANISM ENHANCED THERMOMAGNETIC TWEEZER DEMONSTRATING GRIPPING OF FERROMAGNETIC AND NON-FERROMAGNETIC OBJECTS
(2016)
Wang, Hsin-Min
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Chung, Tien-Kan
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Chen, Chin-Chung
;
Cheng, Chih-Cheng
;
Lin, Chu-Yi
In this article, we demonstrate a mechanical-mechanism enhanced thermomagnetic tweezer. The tweezer which utilizes a thermal-magnetic-mechanical converting consists of two cross jointed Al arms, two Gd sheets, two NdFeB hard magnets, two thermoelectric generators (TEGs), and a ball bearing set. When comparing conventional thermomagnetic grippers, our thermomagnetic tweezer can grip either ferromagnetic or non-ferromagnetic objects and avoid producing temperature-influence to the gripped objects. Experimental results show that we can control TEGs to generate a temperature difference to operate the tweezer to grip small ferromagnetic objects (such as NdFeB hard magnet) and other non-ferromagnetic objects (such as PMMA bulk). The maximum gripping force produced by the tweezer operated by applying the DC current of 1.3 A with the voltage of 0.85 V is 0.59 newton. The corresponding gripping and releasing duration is 7.9 seconds and 8.1 seconds, respectively. According to these results, our tweezer would produce more practical objects-gripping applications.
A NOVEL NANOELECTROMAGNETIC SYSTEM USING MULTIFERROIC/MAGNETOELECTRIC NI-NANO-CHEVRON/PMN-PT HETEROSTRUCTURE TO DEMONSTRATE AN ELECTRIC -FIELD -CONTROLLED PERMANENT MAGNETIC SINGLE -DOMAIN TRANSFORMATION
(2018-01-01)
Cheng, Chih-Cheng
;
Lin, Shin-Hung
;
Chen, Yu-Jen
;
Wang, Hsin-Min
;
Chu, Hou-Jen
In this paper, we report a novel nanoelectromagnetic system using multiferroic/magnetoelectric Ni-nanochevron/PMN-PT heterostructure to demonstrate an electric field -controlled permanent magnetic single-domain transformation. The heterostructure consists of a magnetostrictive Ni-nano-chevron, Pt top and bottom electrodes, and a piezoelectric PMN-PT substrate. In initial state (as demagnetized), the magnetization of the magnetic single domain is stably along the long axis of the nano-chevron. A magnetic field of 3000 Oe (along 45 degree of nano-chevron) is applied to magnetize the Ni-nano-chevron from stable single domain to metastable two-domains. After this, an electric field of 0.8MV/m is applied to the PMN-PT substrate to produce the converse magnetoelectric effect to transform the two-domains. After the electric field is removed, the two-domains are further transformed back to the single-domain. Finally, when comparing the domains before and after applying our approach, approximately 50 % of single-domains are successfully and permanently switched (i.e., magnetization-direction is permanently rotated 180 degrees).
A NOVEL THERMOMAGNETIC ROTATIONAL-ACTUATOR
(2016)
Cheng, Chih-Cheng
;
Chung, Tien-Kan
;
Chen, Chin-Chung
;
Wang, Hsin-Min
;
機械工程學系
In this article, we demonstrate a novel thermomagnetic rotational-actuator. The actuator consists of thermomagnetic material Gadolinium sheets, thermoelectric generators, a rotary aluminum cantilever beam with NdFeB hard magnets fixed on the free-end of the beam, a stainless steel bearing, and a mechanical frame. As conventional magnetic rotational actuators are controlled by using electromagnetic-induction based magnetic-force interaction produced by electromagnets or coils, our actuator is controlled by using a heating-induced magnetic force interaction produced by the thermomagnetic generators. Experimental results show that our actuator is successfully rotated by a controlled sequence of temperature difference generated by the TEGs.
A Rotational Actuator Using a Thermomagnetic-Induced Magnetic Force Interaction
(2018-01-01)
Cheng, Chih-Cheng
;
Chung, Tien-Kan
;
Chen, Chin-Chung
;
Wang, Hsin-Min
;
機械工程學系
In this paper, we demonstrate a rotational actuator using a thermomagnetic-induced magnetic force interaction. The actuator consists of a magnetic rotary beam, stainless-steel bearing, mechanical frame, thermomagnetic Gadolinium sheets, and thermoelectric generators (TEGs). Experimental results show that applying a sequence of currents to the TEGs successfully produces sequential magnetic forces. Consequently, these sequential magnetic forces rotate the beam for revolutions. When applying a sequence set of currents of -0.5 and 1.3 A, the maximum rotation speed and maximum stall torque of the actuator is 3.81 rpm and 136.2 mu Nm, respectively. Most importantly, the operating temperatures of other thermomagnetic (and electrothermal) actuators are usually high, but the operating temperature of our actuator is approximately room temperature (13 degrees C-27 degrees C). Therefore, our actuators have more practical applications. According to the above-mentioned features, we believe our actuator is an important alternative approach to developing future rotational actuators and motors.
ELECTRICAL CONTROL OF MAGNETIC MULTI-DOMAIN TRANSFORMATION IN A SPECIFIC GEOMETRIC-PATTERNED NI NANOSTRUCTURE ON A PIEZOELECTRIC [PB(MG(1/3)NB(2/3))O3](0.68)-[PBTIO3](0.32) SUBSTRATE
(2016)
Chen, Yu-Jen
;
Chung, Tien-Kan
;
Lin, Po-Jung
;
Hung, Chiao-Fang
;
Chu, Hou-Jen
In this paper, we report an electrical control of magnetic multi-domain-walls transformation in an N-shape-patterned Ni nanostructures on a piezoelectric [Pb(Mg1/3Nb2/3)O-3](0.68)-[PbTiO3](0.32) substrate. Based on the converse-magnetoelectric-effect induced domain-wall transformation and the specific N-shape geometry guided domain-wall motion, the domain walls are successfully transformed by an applied electric field of 0.8 MV/m from the transverse domain wall state into the flux closure vortex domain state. These experimental results achieve the electrical control of multi-domain-walls transformation and would create more data storage and memory applications in the future.
Novel coil-less room-temperature resettable magnetic-bead manipulation by using thermomagnetic tracks
(2020-04-01)
Chung, Tien-Kan
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Cheng, Chih-Cheng
;
Reddy, Jaganmohan
;
Chiou, Jeng-Han
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機械工程學系
In this paper, we report a novel coil-less room-temperature resettable magnetic bead manipulation by using thermomagnetic Gd tracks. When comparing to conventional magnetic-track-guided magnetic bead motion, the thermomagnetic Gd tracks (whose Curie temperature is at room temperature) not only can guide the bead motion (as well as the conventional tracks) but also can be reset (demagnetized) in room temperature range without use of any conventional reset coil (i.e., superior than the conventional tracks). The operation and reset principles are described below. When a Gd track is cooled (by a thermoelectric generator, TEG) lower than its Curie temperature (for example: 5 degrees C), the Gd track becomes ferromagnetic. Furthermore, under a magnetic field, the ferromagnetic Gd track enables the magnetic-track-guided magnetic-bead manipulation. Oppositely, when the Gd track is heated (by the TEG) higher than its Curie temperature (for example: 50 degrees C), the Gd track becomes paramagnetic. Thus, under the magnetic field, the paramagnetic Gd track cannot attract the bead. This achieves the track resetting/demagnetizing through a coil-less room-temperature approach and thus disables the magnetic-track-guided magnetic bead manipulation. Furthermore, according to above principles, we can sequentially use TEGs to cool and heat different Gd tracks to guide the bead moving across different tracks, and also reset/demagnetize any track anytime during the bead motion through our approach. These results would be important fundamental elements to provide an alternative magnetic-bead-manipulation for biomedical MEMS systems. (C) 2020 Elsevier B.V. All rights reserved.