Browsing by Author "Lin, Y. -H."

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A comprehensive study of enhanced characteristics with localized transition in interface-type vanadium-based devices
(2020-06-01)
Lin, C. -Y.
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Chen, P. -H.
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Chang, T. -C.
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Huang, W. -C.
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Tan, Y. -F.
In this research, we investigated the conduction mechanism in metal-insulator transition (MIT) materials. Among these MIT materials (NbOx, NiOx, VOx, and TaS2), vanadium oxide-based selectors have been widely investigated because of their high switching speed (similar to 10-ns transition time), sufficient nonlinearity (>10(3)), and endurance stability (similar to 10(10)). Abnormal temperature-dependent degradation in the high resistive state was observed, as was studied in detail by a current fitting analysis and explored theoretically by electric (E-MIT) and thermal (T-MIT) modeling. The results suggest the existence of a MIT region located between the electrode and the localized filament. To improve the localized transition efficiency, we propose an enhanced-type MIT architecture to bypass the E-MIT and T-MIT universal rule with the novel structure of vanadium top electrode device. As compared with a vanadium oxide middle-layer device, the electrical transition efficiency is improved 2-fold as evidenced by thermal cycling material analysis, as well as boosting endurance reliability to 10(7) at 65 degrees C. Finally, for the first time, a potential neuromorphic computing application featuring a damping oscillator has been demonstrated in this enhanced-type MIT architecture, with a high damping ratio with 10-fold smaller area and 5-fold smaller energy than complementary metal-oxide-semiconductor (CMOS) devices. This presents a promising milestone for ultralow power neuromorphic system design and solutions in the near future. (C) 2020 Elsevier Ltd. All rights reserved.
A Volatile RRAM Synapse for Neuromorphic Computing
(2019-01-01)
Covi, E.
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Lin, Y. -H.
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Wang, W.
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Stecconi, T.
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Milo, V.
Neuromorphic computing has emerged as a promising approach for autonomous systems able to learn, adapt, and interact in real time with the environment. To build neuromorphic hardware, the recent development of novel material-based devices such as resistive switching memory (RRAM) has shown to be crucial since this class of devices offers the unique advantage to implement neuron and synaptic functions in silico by device physics, thus avoiding bulky circuits and very complex algorithms. In this work, we first explore volatile switching behaviour of RRAM devices, investigating their ability to capture short-term plasticity (STP) and short-term memory (STM) functionalities. Then, we characterise a volatile RRAM synapse, discussing its potential use in a spiking neural network for speech recognition applications.
Detection of Escherichia coli O157 : H7 using An nanoparticles mediator on an electrochemical amperometric immunobiosensor
(2007)
Chen, S. -H.
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Lin, Y. -H.
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Chuang, Y. -C.
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Lin, Y. -R.
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Chang, C. A.
Detection of Escherichia coli O157 : H7 using Au nanoparticles mediator on an electrochemical amperometric immunobiosensor
(2007-01-01)
Chen, S. -H.
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Lin, Y. -H.
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Chuang, Y. -C.
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Lin, Y. -R.
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Chang, C. A.
Detection of Escherichia coli O157 : H7 using Au nanoparticles mediator on an electrochemical amperometric immunobiosensor
(2007)
Chen, S. -H.
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Lin, Y. -H.
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Chuang, Y. -C.
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Lin, Y. -R.
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Chang, C. A.
Monte Carlo simulations of stress relaxation of entanglement-free Fraenkel chains. I. Linear polymer viscoelasticity
(2007-02-21)
Lin, Y. -H.
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Das, A. K.
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應用化學系
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Department of Applied Chemistry
Shear stress relaxation modulus G(S)(t) curves of entanglement-free Fraenkel chains have been calculated using Monte Carlo simulations based on the Langevin equation, carrying out both in the equilibrium state and following the application of a step shear deformation. While the fluctuation-dissipation theorem is perfectly demonstrated in the Rouse-chain model, a quasiversion of the fluctuation-dissipation theorem is observed in the Fraenkel-chain model. In both types of simulations on the Fraenkel-chain model, two distinct modes of dynamics emerge in G(S)(t), giving a line shape similar to that typically observed experimentally. Analyses show that the fast mode arises from the segment-tension fluctuations or reflects the relaxation of the segment tension created by segments being stretched by the applied step strain-an energetic-interactions-driven process-while the slow mode arises from the fluctuations in segmental orientation or represents the randomization of the segmental-orientation anisotropy induced by the step deformation-an entropy-driven process. Furthermore, it is demonstrated that the slow mode is well described by the Rouse theory in all aspects: the magnitude of modulus, the line shape of the relaxation curve, and the number-of-beads (N) dependence of the relaxation times. In other words, one Fraenkel segment substituting for one Rouse segment, it has been shown that the entropic-force constant on each segment is not a required element to give rise to the Rouse modes of motion, which describe the relaxation modulus of an entanglement-free polymer over the long-time region very well. This conclusion provides an explanation resolving a long-standing fundamental paradox in the success of Rouse-segment-based molecular theories for polymer viscoelasticity-namely, the paradox between the Rouse segment size being of the same order of magnitude as that of the Kuhn segment (each Fraenkel segment with a large force constant H-F can be regarded as basically equivalent to a Kuhn segment) and the meaning of the Rouse segment as defined in the Rouse-chain model. The general agreement observed in the comparison of the simulation and experimental results indicates that the Fraenkel-chain model, while being still relatively simple, has captured the key element in energetic interactions-the rigidity on the segment-in a polymer system. (c) 2007 American Institute of Physics.
Monte Carlo simulations of stress relaxation of entanglement-free Fraenkel chains. II. Nonlinear polymer viscoelasticity
(2007-02-21)
Lin, Y. -H.
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Das, A. K.
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應用化學系
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Department of Applied Chemistry
The nonlinear viscoelastic behavior of the Fraenkel-chain model is studied with respect to the constitutive equation of the Rouse model. Distinctly different from the results of the Rouse model, the Fraenkel-chain model gives the following characteristic nonlinear behavior: (a) The two distinct dynamic modes in the relaxation modulus G(S)(t,lambda)-as observed in the linear region reported in Paper I [Y.-H. Lin and A. K. Das, J. Chem. Phys. 126, 074902 (2007), preceding paper]-or in the first normal-stress difference function G(Psi 1)(t,lambda) are shown to have different strain dependences: strain hardening for the fast mode and strain softening for the slow mode. (b) The Lodge-Meissner relation G(S)(t,lambda)=G(Psi 1)(t,lambda) holds over the whole time range, which has been shown both analytically and by simulation. (c) The second normal-stress difference is nonzero, being positive in the fast-mode region and negative in the slow-mode region. The comparisons between orientation and stress for all tensor components consistently confirm the strong correlation of the slow mode as well as its entropic nature with the segmental-orientation anisotropy as shown in the linear region studied in Paper I. A consequence of this correlation is the applicability of the stress-optical rule in the slow-mode region. This also leads to the expectation that the damping function h(lambda)=G(S)(t,lambda)/G(S)(t,lambda -> 0) and the ratio between the first and second normal-stress differences, N-2(t,lambda)/N-1(t,lambda), are described by the orientation tensor which has the same form as that given by Doi and Edwards [J. Chem. Soc. Faraday Trans. 2 74, 1789 (1978); 74, 1802 (1978)] with independent-alignment approximation for an entangled system. The similarity between the slow mode of an entanglement-free Fraenkel-chain system and the terminal mode of an entangled polymer system as observed in the comparison of theory, simulation, and experiment suggests that the close correlation of the entropic nature of the mode with the orientation anisotropy-as of the Fraenkel segment or the primitive step in the Doi-Edwards theory-is a generally valid physical concept in polymer viscoelasticity. (c) 2007 American Institute of Physics.
The Rouse-Mooney model for coherent quasielastic neutron scatterings of single chains well entangled in polymer melts
(2008-06-14)
Lin, Y. -H.
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Huang, C. -F.
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應用化學系
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Department of Applied Chemistry
The dynamic structure factor (DSF) for single (labeled) chains well entangled in polymer melts has been developed based on the Rouse-Mooney picture; the DSF functions derived from the Langevin equations of the model in both discrete and continuous forms are given. It is shown that for all practical purposes, it is sufficient to use the continuous form to analyze experimental results in the "safe" q region (q being the magnitude of the scattering wave vector q) where the Rouse-segment-based theories are applicable. The DSF form reduces to the same limiting form as that of the free Rouse chain as q(2)a(2) or q(2)R(2)->infinity (a and R being the entanglement distance and the root mean square end-to-end distance, respectively), confirming what has been expected physically. The natural reduction to the limiting form allows the full range of DSF curves to be displayed in terms of the reduced Rouse variable q(2)(Z(d)t)(0.5) in a unified way. The displayed full range represents a framework or "map," with respect to which effects occurring in different regions of the DSF may be located and studied in a consistent manner. One effect is the significant or noticeable deviations of the theoretical DSF curves from the limiting curve in the region similar to 4>q(2)(Z(d)t)(0.5)>similar to 0.1 (a time region where t