Browsing by Author "Hsu, Chien-Hua"

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A Comprehensive Modeling Framework for Ferroelectric Tunnel Junctions
(2019-01-01)
Huang, Hsin-Hui
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Wu, Tzu-Yun
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Chu, Yueh-Hua
;
Wu, Ming-Hung
;
Hsu, Chien-Hua
A modeling framework for ferroelectric tunnel junctions (FTJs) that considers nonpolar interfacial layers (ILs), multi-domain polarization, and complete ferroelectric/capacitive/tunneling currents simultaneously is proposed. This model explains both read and write operations including the controversial switching polarities of FTJ. We also provide useful guidelines for optimizing FTJ performance where the location of IL and the effective thickness ratio between ferroelectric and interfacial layers are found to be most critical.
Adjustable implant electrode system and implant electrode assembly thereof
(2010-05-20)
Choi, Charles Tak-Ming
;
Hsu, Chien-Hua
An adjustable implant electrode system comprises an adjustable implant electrode assembly and an adjustment device for adjusting the adjustable implant electrode assembly to a desired position. The adjustable implant electrode assembly comprises an implant, a plurality of electrodes, and a plurality of magnetic components. The electrodes are disposed in the implant for providing stimulating currents according to a control signal. The magnetic components are combined with the electrodes in one-to-one correspondence. The adjustment device comprises a control unit, an excitation unit, and one or more magnetic units. The control unit is used to select one or more magnetic components to be moved from the magnetic components, and the excitation unit is used to excite the selected one or more magnetic components for the same to generate a magnetic pole, and the magnetic unit is adapted to generate a magnetic filed to drive the magnetic pole and accordingly move the implant.
Conditions for Generating Virtual Channels in Cochlear Prosthesis Systems
(2009-03-01)
Choi, Charles T. M.
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Hsu, Chien-Hua
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分子醫學與生物工程研究所
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資訊工程學系
;
Institute of Molecular Medicine and Bioengineering
Simultaneous electrical stimulation of neighboring electrodes in cochlear prosthesis systems generates channel interaction. However, intermediate channels, or virtual channels between the neighboring electrodes can be created through controlled channel interaction. This effect may be exploited for sending new information to the hearing nerves by stimulating in a suitable manner. The actual stimulation sites are therefore not limited to the number of electrodes. Clinical experiments, however, show that virtual channels are not always perceived. In this paper, electrical simulation with finite element analysis on a half turn human cochlea model is adopted to model the virtual channel effect, and the conditions for generating virtual channels are discussed. Five input current ratios (100/0, 70/30, 50/50, 30/70, 0/100) are applied to generate virtual channels. Three electrode arrays parameters are taken into consideration: distance between electrode contact and modiolus, spacing between adjacent electrode contacts and scale of electrode contact size. By observing the activating function contours, the virtual channel patterns and performances can be measured and examined. The results showed that a broad excitation pattern is necessary to produce the kind of electrode interaction that can form distinct virtual channels.
Sub-nA Low-Current HZO Ferroelectric Tunnel Junction for High-Performance and Accurate Deep Learning Acceleration
(2019-01-01)
Wu, Tzu-Yun
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Huang, Hsin-Hui
;
Chu, Yueh-Hua
;
Chang, Chih-Cheng
;
Wu, Ming -Hung
This paper presents a unique opportunity of HZO ferroelectric tunnel junction (FTJ) for in-memory computing. The device operates at an extremely low sub-nA current while simultaneously achieving 50-ns fast switching, > 10(7) cycling endurance, > 10-yr retention, minimal variability, and analog state modulation. We analyze an FTJ-based deep binary neural network. It achieves better accuracy and remarkable 702, 101, and 7 x 10(4) times improvements in power, area, and energy area product efficiency compared with those using NVMs with a typical mu A cell current designed for fast memory access.
Visualization of clogs developed from interaction between APDC and low-level radwaste relevant nuclides on RO membranes: A LA-ICP-MS study
(2014-04-15)
Chen, Lian-Song
;
Wang, TsingHai
;
Hsieh, Yi-Kong
;
Hsu, Chien-Hua
;
Lin, Justin Chun-Te
In this study, we used LA-ICP-MS to visualize the fouling induced by seeded filtration for efficient removing liquid low-level radwaste relevant nuclides using a reverse osmosis (RO) membrane. Evidenced by a significant permeate flux drop, these APDC additives pronouncedly increased the rejection by around 20% (from 68% to 84%) for cobalt, 30% for strontium (from 55% to 71%), and 70% for cesium (from 20% to 34%). Surface mapping using LA-ICP-MS showed that the hot zones of Co, Sr, and Cs in the APDC-Co, APDC-Sr and APDC-Cs systems were perfectly superimposed with the locations of the S moiety of APDC. This suggested that the improved rejection is closely related to the formation of APDC-metal complexes, and the possible coprecipitation of these elements with APDC-metal complexes. Further depth profile analyses revealed that the fouling mainly occurred in the first 2-6 pm of the RO membrane. Fitted with the Hermia model, it was evident that APDC additives facilitate the formation of complete blocking, intermediate blocking, and standard blocking, and as a consequence enhance Co rejection. By contrast, cake formation induced by APDC additives was mainly responsible for the better rejection of Sr and Cs. Importantly, our depth profile analyses undoubtedly suggested that a large particle/colloid is able to penetrate deeply into the membrane despite its pore size is much smaller than those particles/colloids. (C) 2014 Elsevier B.V. All rights reserved.