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Hsu H.-L.,National Taiwan University | Teng L.-J.,National Chiao Tung University | Chen Y.-C.,Institute of Electronics Engineering | Hsu W.-L.,NTHU | And 6 more authors.
Advanced Materials | Year: 2010

Carbon nanotubes were grown on flexible polylmide substrates at temperatures below 400°C as electrodes for extracellularly neuronal recording. The electrical charge-transfer and electrochemical properties of such CNT electrodes were enhanced by UV-ozone exposure, which induced the formation of C-O, C=O, and O-C=O bonds and reduced the CNT/ electrolyte Interfacial Impedance while increasing the interfacial capacitance. Figure presented © 2010 WILEY-VCH Verlag GmbH & Co. KGaA. Source


Yen S.-J.,National Tsing Hua University | Hsu W.-L.,NTHU | Chen Y.-C.,Institute of Electronics Engineering | Su H.-C.,National Tsing Hua University | And 4 more authors.
Biosensors and Bioelectronics | Year: 2011

This paper reports the success of amino-functionalization on multi-walled carbon nanotubes (MWCNTs) to promote neuronal cells growth on MWCNT electrode for extracellular recording, attributed to the formation of positive charge of NH2 molecules on their surfaces. Besides, the surface of MWCNT electrode becomes hydrophilic after amino-functionalization (AF-MWCNTs) which can enhance electrical conductivity because of lower MWCNT/electrolyte interfacial impedance and higher interfacial capacitance. Durability tests show that electrical characteristics of the MWCNTs treated by 2wt% 1,4-diaminobutane solution (2wt%-AF-MWCNTs) can last for at least six months in air ambient. The neural recording of crayfish shows that 2wt%-AF-MWCNTs can provide better capability on detecting action potentials of caudal photoreceptor (CPR) interneuron compared to suction glass pipette from the evidence of a higher S/N ratio (126 versus 23). The amino-functionalized MWCNT electrode is feasible for long-term recording application according to the results of biocompatibility tests. As the MWCNTs were directly synthesized on Si-based substrates by catalyst-assisted thermal chemical vapor deposition (CVD) at a low temperature (400°C), these self-aligned MWCNT electrodes could be friendly implemented in integrated circuits fabrications. © 2011. Source


Su H.-C.,National Tsing Hua University | Chen C.-H.,Institute of Nano Engineering and Micro System | Chen Y.-C.,Institute of Electronics Engineering | Yao D.-J.,Institute of Nano Engineering and Micro System | And 3 more authors.
Carbon | Year: 2010

The effect of microwave (MW) treatment to improve the adhesion of carbon nanotubes (CNTs) to a Ni/Ti/Au/SiO 2/Si substrate was examined. CNTs were synthesized at a low temperature (400 °C) by thermal chemical vapor deposition to avoid metal peeling. Results demonstrated that nearly 100% of MW-treated CNTs remained on the substrates even after sonication in a buffer solution. This was a significant improvement of adhesion compared to preparations not undergoing MW treatment, where almost no CNTs remained. Transmission electron microscopy of cross sections showed that before MW treatment, CNTs with Ni nanoparticles were located on the upper part of the Ti underlayer, whereas after MW treatment they were embedded in the Ti underlayer. Based on these results, a mechanism of adhesion improvement by MW treatment is proposed. © 2009 Elsevier Ltd. All rights reserved. Source


Trenz F.,Institute of Electronics Engineering | Kalpen V.,Institute of Electronics Engineering | Weigel R.,Institute of Electronics Engineering | Kissinger D.,Ihp Microelectronics | Kissinger D.,TU Berlin
2015 IEEE MTT-S International Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications, IMWS-BIO 2015 - Proceedings | Year: 2015

In this paper, a blood-equivalent liquid is presented. The phantom material at room temperature is a valid representation of blood at body temperature in the frequency range from 2 to 3 GHz with an maximum deviation of ±1.5 in e' and ±2.8 in e'. The effect of a hypertonic variation of the plasma hydration level has been modeled by varying the amount of water ±14 % in the tissue-equivalent fluid. Transmission based measurements have been performed on a tube phantom of PMMA with narrowband patch antennas on flexible substrates. The antennas have been placed at opposite sides of the phantom and measurements have been performed at different hydration levels of the substitute liquid. A clear distinction of the levels can be seen in both magnitude and phase of the transmission coefficient. © 2015 IEEE. Source


Gardill M.,Institute of Electronics Engineering | Weigel R.,Institute of Electronics Engineering | Koelpin A.,Institute of Electronics Engineering
Proceedings of the 2012 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications, APWC'12 | Year: 2012

A modification of the famous Bow Tie antenna element for wideband Direction-Of-Arrival estimation antenna arrays is designed. A broadband impedance match from 5 GHz to 14.5 GHz corresponding to a 97% bandwidth, as well as a very stable radiation pattern over a 37% bandwidth from 5.5 GHz to 8 GHz is achieved. A method for pattern stabilization using parasitic edge currents is shown. In addition the proposed design uses a double layer substrate and hence aims at direct integration of the feed network and analog RF circuitry directly into the antenna array. The particular design is suited for low-cost integration and optimized for a wireless high-precision localization system. © 2012 IEEE. Source

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