Browsing by Author "Tsai, Jengjan"

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Application of 9 x 9 grid gas bags pressure control technology to imprinting of various microstructures
(2016-01-01)
Weng, Yung-Jin
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Tsai, Jengjan
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物理研究所
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Institute of Physics
This study proposed a pressure control technology of 9 x 9 grid gas bags for application to imprinting of various microstructures. First, the 9 x 9 grid imprinting system was designed and constructed. The novel system used laser light-emitting elements for correction through geometric method before the experiment. Moreover, the proposed system can set the imprint inclined plane in small inclination angle and accurate control pressure of 9 x 9 grid areas to achieve novel imprinting process of microstructures. The experimental results showed that 9 x 9 grid gas bag pressure control technology can accurately correct the plane of the imprinting system before experiment, accurately set the inclined plane required for the experiment, and accurately imprint microstructures. (C) 2016 Elsevier GmbH. All rights reserved.
Collective flow dynamics across a bacterial carpet: Understanding the forces generated
(2014-11-17)
Hsiao, Yi-Teng
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Wang, Jing-Hui
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Wu, Kuan-Ting
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Tsai, Jengjan
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Chang, Cheng-Hung
Bacterial carpets consist of randomly anchored uni-polar-flagellated sodium-motive bacterial matrix are prepared by flow deposition. Collective flow dynamics across the bacterial carpets are probed with optical tweezers-microsphere assay. Around the center of a uniform bacterial cluster, collective forces that pull microsphere towards carpet surface are detected at a distance of 10 mu m away from carpets. At sodium-motive driving over a critical value, the force magnitudes increase abruptly, suggesting a threshold-like transition of hydrodynamic synchronization across bacterial carpet. The abrupt force increase is explained in term of bifurcation to phase synchronization in a noisy non-linearly coupled rotor array mediated by hydrodynamic interactions. (C) 2014 AIP Publishing LLC.
Generalized path integral method for Elliott-Yafet spin relaxations in quantum wells and narrow wires
(2012-02-22)
Tsai, Jengjan
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Chang, Cheng-Hung
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物理研究所
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Institute of Physics
We generalized the semiclassical path integral method originally used in the D'yakonov-Perel' mechanism to study the spin relaxation of the Elliott-Yafet mechanism in low-dimensional systems. In quantum wells, the spin properties calculated by this method confirmed the experimental results. In two-dimensional narrow wires, size and impurity effects on the Elliott-Yafet relaxation were predicted, including the wire-width-dependent relaxation time, the polarization evolution on the sample boundaries, and the relaxation behavior during the diffusive-ballistic transition. These properties were compared with those of the D'yakonov-Perel' relaxation calculated under similar conditions. For ballistic narrow wires, we derived an exact relation between the Elliott-Yafet relaxation time and the wire width, which confirmed the above simulations.
Semiclassical path integral approach for spin relaxations in narrow wires
(2009-03-01)
Chang, Cheng-Hung
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Tsai, Jengjan
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Lo, Hui-Fen
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Mal'shukov, A. G.
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數學建模與科學計算所(含中心)
The semiclassical path integral (SPI) method has been applied for studying spin relaxation in a narrow two-dimensional strip with the Rashba spin-orbit interaction. Our numerical calculations show good agreement with the experimental data, although some features of experimental results are not clear yet. We also calculated the relaxation of a uniform spin-density distribution in the ballistic regime of very narrow wires. With the decreasing wire width, the spin polarization exhibits a transition from the exponential decay to the oscillatory Bessel-type relaxation. The SPI method has also been employed to calculate the relaxation of the particularly long-lived helix mode. Good agreement has been found with calculations based on the diffusion theory.