Browsing by Author "Hsu, Wei-Hsuan"

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A Miniaturized Electromagnetic Generator With Planar Coils and Its Energy Harvest Circuit
(2009-10-01)
Liao, Lun-De
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Chao, Paul C. -P.
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Chen, Jian-Ting
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Chen, Wei-Dar
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Hsu, Wei-Hsuan
This study presents design, analysis and experiment of a miniaturized rotary generator in size of 10 10 2 mm and its compact energy harvest circuit chip. The designed generator consists of patterned planar copper coils and a multipolar hard magnet ring made of NdFeB. To perform modeling, a harmonic-like magnetic field model along the circumferential path of each magnetic pole is assumed with the assistance from measured peak magnetic flux densities. This is followed by the application of Faraday's law to predict generated electromotive forces (EMFs) in terms of the relative rotational speed between the magnet ring and coils. The genetic algorithm (GA) is next applied to optimize the critical dimensions of the miniaturized generator. The theoretical model of this power microgenerator is evaluated and compared with experimental results, and it is found that the analytical simulation shows a good agreement with the experimental results. The optimized generator offers 4.5 V and 7.23m W in root mean square (rms) at 10 000 r/min. With microgenerator successfully fabricated, a novel energy harvest circuit employing Dickson charge pump is designed and fabricated via the 0.35-um process offered by National Chip Implementation Center (CIC) of Taiwan. This charge pump circuit owns the merit of almost-zero thresholds of employed metal-oxide-semiconductor (MOS) transistors, enabling the conversion of low-power alternating current (ac) signals by the microgenerator to direct current (dc) ones.
A New Active 3D Optical Proximity Sensor Array and Its Readout Circuit
(2014-07-01)
Huang, Sheng-Chieh
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Hsu, Wei-Hsuan
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Chao, Paul C. -P.
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Tsai, Che Hung
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電機工程學系
A new 3-D proximity sensor panel (3-D touch panel) for a single object is proposed in this paper. The sensor panel consists of a photo detector (PD) array as active pixels, along with its optics design, a computation algorithm, and sensing circuitry to eliminate background lighting. This sensing panel system acts as a noncontact 3-D positioning sensor, which is able to sense spatial positions of the object without realistic touching to the panel. New active readout pixel circuits for the PDs are designed to efficiently convert PD-received light intensities to voltage signals. It offers high readout resolutions, larger output ranges, and lower noises, as compared with the conventional active pixel sensor (APS) with a 3T-structure (called 3T-APS). Toward success of the sensor, background light is eliminated by a specially designed sample and hold circuitry, whereas a computation algorithm for 3-D object detection is developed based on photometry. The circuit is fabricated by Taiwan Semiconductor Manufacturing Company 0.35-mu m 2P4M 3.3 V mixed signal CMOS process. Sensing trials for a moving object are finally conducted. The sensor performance is validated and further illustrated by a Labview program. The sensing errors of a sphere object are successfully limited to 5% in percentages.
A New Active 3D Optical Proximity Sensor Array and Its Readout Circuit
(2013-01-01)
Chao, Paul C. -P.
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Hsu, Wei-Hsuan
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Tsai, Che-Hung
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電機工程學系
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Department of Electrical and Computer Engineering
An on-line optical bench tester machine for evaluating lens quality
(2014-08-01)
Chao, Paul C-P.
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Kao, Yung-Hua
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Hsu, Wei-Hsuan
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Huang, Yan-Pean
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電機工程學系
This study is dedicated to develop an on-line automatic optical bench tester (OBT) machine for evaluating the image quality of a camera lens that is used in a lens module of a cell phone. This tester is not only suitable for conventional solid lens, but also applicable to the developing cutting-edge tunable liquid crystal lens. The testing is accomplished via a specially-designed OBT machine, which is able to automatically move the test lens based on feedback images in the optical system in the OBT to the axial position that leads to best imaging quality and also successfully measure its focus length. In the designed OBT, a commercial inspection chart is employed, along with an automatic lens-feeding machine for a quick estimate on the best possible focusing quality, which is evaluated by the well-known modulation transfer function (MTF). For actuating the feeding machine, an algorithm, assisted by the feedback MTFs, is proposed to move the test lens to the particular position that renders the best quality. In this way, the focus length-effective focal length (EFL)-of the test lens can be obtained. The proposed algorithm in fact needs much less time of actuation than a traditional tester to obtain EFL of the test lens. The designed and constructed tester is capable of measuring varied optical performance indices for the next-generation tunable lens, like liquid crystal lens.
Effects of long-term exercise on arrhythmogenesis in aged hypertensive rats
(2018-11-01)
Sung, Yen-Ling
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Wu, Chih-En
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Syu, Jhen-Yang
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Kuo, Terry B. J.
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Li, Jai-Yi
Chronic hypertension is a multifactorial disease that is highly associated with cardiovascular disorders. Physical activity, such as long-term exercise, is advocated as a treatment for hypertension, but the responses of different age groups to long-term exercise are unknown. We used aged spontaneous hypertensive rats (SHRs, 80 weeks old) to test the hypothesis that long-term exercise compensated for deficient autonomic control and reduced susceptibility to ventricular tachycardia (VT) and ventricular fibrillation (VF) in this animal model. The aged SHRs were divided into control and voluntary exercise groups. Ambulatory electrocardiography was recorded for the heart rate variability (HRV) analysis. Programmed stimulation was applied to exposed hearts to induce ventricular arrhythmia in situ. Then, the hearts were isolated for an optical mapping study. The results showed that increased HRV indices were broadly related to vagal dominance in the high-intensity exercise group. Exercise altered the electrical propagation dynamic properties, such as the action potential duration restitution (APDR). Furthermore, the VF inducibility decreased with increased exercise intensity. Taken together, our results suggest that long-term exercise reduces the risk of arrhythmogenesis in aged SHRs through enhanced vagal control and stabilized electrical dynamics.
Pleiotropic Effects of Myocardial MMP-9 Inhibition to Prevent Ventricular Arrhythmia
(2016-12-14)
Weng, Ching-Hui
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Chung, Fa-Po
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Chen, Yao-Chang
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Lin, Shien-Fong
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Huang, Po-Hsun
Observational studies have established a strong association between matrix metalloproteinase-9 (MMP-9) and ventricular arrhythmia. However, whether MMP-9 has a causal link to ventricular arrhythmia, as well as the underlying mechanism, remains unclear. Here, we investigated the mechanistic involvement of myocardial MMP-9 in the pathophysiology of ventricular arrhythmia. Increased levels of myocardial MMP-9 are linked to ventricular arrhythmia attacks after angiotensin II (Ang II) treatment. MMP-9-deficient mice were protected from ventricular arrhythmia. Increased expressions of protein kinase A (PKA) and ryanodine receptor phosphorylation at serine 2808 (pS2808) were correlated with inducible ventricular arrhythmia. MMP-9 deficiency consistently prevented PKA and pS2808 increases after Ang II treatment and reduced ventricular arrhythmia. Calcium dynamics were examined via confocal imaging in isolated murine cardiomyocytes. MMP-9 inhibition prevents calcium leakage from the sarcoplasmic reticulum and reduces arrhythmia-like irregular calcium transients via protein kinase A and ryanodine receptor phosphorylation. Human induced pluripotent stem cell-derived cardiomyocytes similarly show that MMP-9 inhibition prevents abnormal calcium leakage. Myocardial MMP-9 inhibition prevents ventricular arrhythmia through pleiotropic effects, including the modulation of calcium homeostasis and reduced calcium leakage.