Chung Yuan Christian University

About: Chung Yuan Christian University is a education organization based out in Taoyuan City, Taiwan. It is known for research contribution in the topics: Membrane & Fuzzy logic. The organization has 9819 authors who have published 11623 publications receiving 213139 citations. The organization is also known as: Tiong-gôan-tāi-ha̍k & CYCU.

Polymerization of aniline under various concentrations of APS and HCl

Abstract: Effects from various initial molar ratios of aniline (AN), ammonium peroxydisulfate (APS) and HCl ([AN]:[APS]:[HCl]) on the polymerization of AN were investigated. First, a scheme derived from a molecular point of view was proposed to distinguish formation mechanisms based on their initial conditions. Thereafter, by choosing a relatively low ratio of [APS]/[AN]=0.23 at [AN]=0.27 M, three cases can be categorized according to this scheme: (A) [AN]≫[HCl], (B) [AN] slightly larger than [HCl] and (C) [AN]<[HCl]. For case (A), the initial solution has a richness of neutral ANs. Both the doped and the dedoped samples are confirmed to have features of phenazine-like oligomers. For case (C), neutral ANs are almost protonated to become anilinium cations. The final products possess features of polyaniline. For case (B), the samples possess both features from cases (A) and (C). Finally, the formation mechanisms for polymerization of AN were discussed. A schematic diagram to reveal the effects from various initial molar ratios of [AN]:[APS]:[HCl] on the polymerization of aniline (AN) is proposed with [APS]/[AN]=0.23 at [AN]=0.27 M. For [AN]=[HCl], the initial solution has a richness of neutral ANs. The as-obtained samples have features of phenazine-like oligomers. For [AN]<[HCl], neutral ANs are almost protonated to become anilinium cations. The as-obtained samples possess features of polyaniline. Finally, the formation mechanisms for polymerization of AN into various forms of nanostructures were discussed.

Effect of Reactive Channel Functional Groups and Nanoporosity of Nanoscale Mesoporous Silica on Properties of Polyimide Composite

Abstract: Novel covalently bonded nanoscale mesoporous silica (NMS)/polyimide (ODPA−BAPP) nanocomposites were synthesized through the bridge 3-aminopropyltrimethoxysilane. Abundant reactive amino functional groups inside the mesopore channels of NMS can interconnect with numerous polyimide main chains, forming multilinked and complex NMS/PI networks. These multilinkages, NMS inherent nanoporosity, and the uniform dispersion of NMS in polyimide significantly improve thermal stability, mechanical properties, elongation, moisture absorption, and dielectric constant of these novel materials over those of neat polyimide. For instance, the storage modulus is increased by 160%, the decomposition temperature by 35.7 °C, and the glass transition temperature by 14.5 °C. The maximum elongation increases by 66%, hardly observed in other polyimide nanocomposites, probably because the covalent bond and NMS nanopore can absorb more energy than pristine poyimide before failure. The nanoporosity of the core of the NH2-NMS material ...

First-order allpass filter and sinusoidal oscillators using DDCCs

Abstract: A voltage-mode first-order allpass filter using one differential difference current conveyor (DDCC), one grounded capacitor and one floating resistor is presented. No passive component matching constraints are required. Because the output impedance of the proposed allpass filter is low, the output terminal can be directly connected to the next stage. Using the proposed first-order allpass filter as a basic building block, a new quadrature oscillator and even-phase sinusoidal oscillators can be obtained. The simulation results confirm the theoretical analysis.

Virtual Metrology Technique for Semiconductor Manufacturing

Abstract: IC metrology is a necessary means for measuring the fabrication performance in the semiconductor industry. It is significant for yield enhancement and process control. However, real-time monitoring of wafer production is required in recent years especially for the 300 mm semiconductor manufacturing. Therefore, virtual metrology (VM) is developed for the tide of demand. It is a novel technology to predict the process results based on the previous metrology measurements, instead of measuring practically. Consequently it can assist in achieving total quality management and enable run-to-run control. In this paper a systematic methodology for virtual metrology is proposed. This VM system which is mainly designed for the process subject to linear process drift consists of a piecewise linear neural network and a fuzzy neural network. Because many semiconductor processes exhibit inevitable steady drifts in nature, the design of piecewise linear neural network is to approximate the drift trend. In addition, the influence of process recipe on fabrication outcome is learned using the fuzzy neural network. The system has good generalization capability and performance. Thus, it provides an effective and economical solution for metrology prediction.

Polybenzimidazole membranes modified with polyelectrolyte-functionalized multiwalled carbon nanotubes for proton exchange membrane fuel cells

Abstract: Nafion- and polybenzimidazole (PBI)-functionalized multiwalled carbon nanotubes (MWCNT–Nafion and MWCNT–PBI) have been prepared through an ozone mediated process and used as additives in the preparation of PBI/MWCNT nanocomposite membranes. Scanning electron microscopy images of the nanocomposite membranes show a high compatibility between functionalized-MWCNTs and the PBI matrix. Addition of the functionalized MWCNTs enhances the thermal and mechanical properties of the composite membranes. Moreover, compared to the proton conductivity of 0.03 S cm−1 of the phosphoric acid (PA)-doped PBI membrane, the PA-doped nanocomposite membranes containing 0.2 wt% of MWCNT–Nafion (N-0.2) and MWCNT–PBI (P-0.2) have proton conductivities of 0.05 and 0.08 S cm−1 at 160 °C under anhydrous conditions, respectively. In single cell tests at 150 °C, N-0.2 and P-0.2 demonstrated maximum power densities of 700 and 600 mW cm−2, respectively. The values are much higher than that found with pristine PBI membrane (530 mW cm−2).