The Experts below are selected from a list of 28842 Experts worldwide ranked by ideXlab platform
Trung Nguyen - One of the best experts on this subject based on the ideXlab platform.
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Controlling the ionic polymer/gas Interface Property of a PEM fuel cell catalyst layer during membrane electrode assembly fabrication
Journal of Applied Electrochemistry, 2020Co-Authors: Regis P. Dowd, Yuanchao Li, Trung NguyenAbstract:During high current density operation, water production in the polymer electrolyte membrane fuel cell (PEMFC) cathode catalyst layer can negatively affect performance by lowering mass transport of oxygen into the cathode. In this paper, a novel heat treatment process for controlling the ionic polymer/gas Interface Property of the fuel cell catalyst layer is investigated and then incorporated into the membrane electrode assembly (MEA) fabrication process. XPS characterization of the catalyst layer's ionomer-gas Interface at its outer surface and its sublayers’ surfaces obtained by scraping off successive layers of the catalyst layers confirms that a hydrophobic ionomer Interface can be achieved across the catalyst layer using a specific heat treatment condition. Based on the results of the catalyst layer study, the MEA fabrication process is modified to identify heat treatment configuration and conditions that will create an optimal hydrophobic ionomer-gas Interface inside the cathode catalyst layer. Finally, fuel cell tests conducted on the conventional and new MEAs under different operating temperatures show the performance of the fuel cells with the treated MEAs was > 130% higher than that with the conventional MEA at 25 °C and 70 °C with humidified air and > 45% higher at 70 °C with dry air. The durability of the hydrophobic treatment on the cathode catalyst layer ionomer is also confirmed by the accelerated stress test. Graphic abstract PEMFC Catalyst Layer with Hydrophobic Ionomer/Gas Interface
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controlling the ionic polymer gas Interface Property of a pem fuel cell catalyst layer during membrane electrode assembly fabrication
Journal of Applied Electrochemistry, 2020Co-Authors: Regis P. Dowd, Yuanchao Li, Trung NguyenAbstract:During high current density operation, water production in the polymer electrolyte membrane fuel cell (PEMFC) cathode catalyst layer can negatively affect performance by lowering mass transport of oxygen into the cathode. In this paper, a novel heat treatment process for controlling the ionic polymer/gas Interface Property of the fuel cell catalyst layer is investigated and then incorporated into the membrane electrode assembly (MEA) fabrication process. XPS characterization of the catalyst layer's ionomer-gas Interface at its outer surface and its sublayers’ surfaces obtained by scraping off successive layers of the catalyst layers confirms that a hydrophobic ionomer Interface can be achieved across the catalyst layer using a specific heat treatment condition. Based on the results of the catalyst layer study, the MEA fabrication process is modified to identify heat treatment configuration and conditions that will create an optimal hydrophobic ionomer-gas Interface inside the cathode catalyst layer. Finally, fuel cell tests conducted on the conventional and new MEAs under different operating temperatures show the performance of the fuel cells with the treated MEAs was > 130% higher than that with the conventional MEA at 25 °C and 70 °C with humidified air and > 45% higher at 70 °C with dry air. The durability of the hydrophobic treatment on the cathode catalyst layer ionomer is also confirmed by the accelerated stress test. PEMFC Catalyst Layer with Hydrophobic Ionomer/Gas Interface
Regis P. Dowd - One of the best experts on this subject based on the ideXlab platform.
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Controlling the ionic polymer/gas Interface Property of a PEM fuel cell catalyst layer during membrane electrode assembly fabrication
Journal of Applied Electrochemistry, 2020Co-Authors: Regis P. Dowd, Yuanchao Li, Trung NguyenAbstract:During high current density operation, water production in the polymer electrolyte membrane fuel cell (PEMFC) cathode catalyst layer can negatively affect performance by lowering mass transport of oxygen into the cathode. In this paper, a novel heat treatment process for controlling the ionic polymer/gas Interface Property of the fuel cell catalyst layer is investigated and then incorporated into the membrane electrode assembly (MEA) fabrication process. XPS characterization of the catalyst layer's ionomer-gas Interface at its outer surface and its sublayers’ surfaces obtained by scraping off successive layers of the catalyst layers confirms that a hydrophobic ionomer Interface can be achieved across the catalyst layer using a specific heat treatment condition. Based on the results of the catalyst layer study, the MEA fabrication process is modified to identify heat treatment configuration and conditions that will create an optimal hydrophobic ionomer-gas Interface inside the cathode catalyst layer. Finally, fuel cell tests conducted on the conventional and new MEAs under different operating temperatures show the performance of the fuel cells with the treated MEAs was > 130% higher than that with the conventional MEA at 25 °C and 70 °C with humidified air and > 45% higher at 70 °C with dry air. The durability of the hydrophobic treatment on the cathode catalyst layer ionomer is also confirmed by the accelerated stress test. Graphic abstract PEMFC Catalyst Layer with Hydrophobic Ionomer/Gas Interface
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controlling the ionic polymer gas Interface Property of a pem fuel cell catalyst layer during membrane electrode assembly fabrication
Journal of Applied Electrochemistry, 2020Co-Authors: Regis P. Dowd, Yuanchao Li, Trung NguyenAbstract:During high current density operation, water production in the polymer electrolyte membrane fuel cell (PEMFC) cathode catalyst layer can negatively affect performance by lowering mass transport of oxygen into the cathode. In this paper, a novel heat treatment process for controlling the ionic polymer/gas Interface Property of the fuel cell catalyst layer is investigated and then incorporated into the membrane electrode assembly (MEA) fabrication process. XPS characterization of the catalyst layer's ionomer-gas Interface at its outer surface and its sublayers’ surfaces obtained by scraping off successive layers of the catalyst layers confirms that a hydrophobic ionomer Interface can be achieved across the catalyst layer using a specific heat treatment condition. Based on the results of the catalyst layer study, the MEA fabrication process is modified to identify heat treatment configuration and conditions that will create an optimal hydrophobic ionomer-gas Interface inside the cathode catalyst layer. Finally, fuel cell tests conducted on the conventional and new MEAs under different operating temperatures show the performance of the fuel cells with the treated MEAs was > 130% higher than that with the conventional MEA at 25 °C and 70 °C with humidified air and > 45% higher at 70 °C with dry air. The durability of the hydrophobic treatment on the cathode catalyst layer ionomer is also confirmed by the accelerated stress test. PEMFC Catalyst Layer with Hydrophobic Ionomer/Gas Interface
Haimei Gong - One of the best experts on this subject based on the ideXlab platform.
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Interface Property of silicon nitride films grown by inductively coupled plasma chemical vapor deposition and plasma enhanced chemical vapor deposition on in0 82al0 18as
Infrared Physics & Technology, 2015Co-Authors: Hengjing Tang, Xiumei Shao, Xing Huang, Rui Wang, Tao Li, Xue Li, Haimei GongAbstract:Abstract Au/silicon nitride/In 0.82 Al 0.18 As metal insulating semiconductor (MIS) capacitors were fabricated and then investigated by capacitance voltage ( C – V ) test at variable frequencies and temperatures. Two different technologies silicon nitride (SiN x ) films deposited by inductively coupled plasma chemical vapor deposition (“ICPCVD”) and plasma enhanced chemical vapor deposition (“PECVD”) were applied to the MIS capacitors. Fixed charges ( N f ), fast ( D it ) and slow ( N si ) Interface states were calculated and analyzed for the different films deposition MIS capacitors. The D it was calculated to be 4.16 × 10 13 cm −2 eV −1 for “ICPCVD” SiN x MIS capacitors, which was almost the same to that of “PECVD” SiN x MIS capacitors. The D it value is obviously higher for the extended wavelength In x Ga 1− x As ( x > 0.53) epitaxial material as a result of lattice mismatch with substrate. Compared to the results of “PECVD” SiN x MIS capacitors, the N si was significantly lower and the N f was slightly lower for “ICPCVD” SiN x MIS capacitors. X-ray photoelectron spectroscopy (XPS) analysis shows good quality of the “ICPCVD” grown SiN x . The low temperature deposited SiN x films grown by “ICPCVD” show better effect on decreasing the dark current of In x Ga 1− x As photodiodes.
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Interface Property of silicon nitride films grown by inductively coupled plasma chemical vapor deposition and plasma enhanced chemical vapor deposition on in0 82al0 18as
Infrared Physics & Technology, 2015Co-Authors: Ming Shi, Hengjing Tang, Xiumei Shao, Xing Huang, Rui Wang, Gaoqi Cao, Haimei GongAbstract:Abstract Au/silicon nitride/In 0.82 Al 0.18 As metal insulating semiconductor (MIS) capacitors were fabricated and then investigated by capacitance voltage ( C – V ) test at variable frequencies and temperatures. Two different technologies silicon nitride (SiN x ) films deposited by inductively coupled plasma chemical vapor deposition (“ICPCVD”) and plasma enhanced chemical vapor deposition (“PECVD”) were applied to the MIS capacitors. Fixed charges ( N f ), fast ( D it ) and slow ( N si ) Interface states were calculated and analyzed for the different films deposition MIS capacitors. The D it was calculated to be 4.16 × 10 13 cm −2 eV −1 for “ICPCVD” SiN x MIS capacitors, which was almost the same to that of “PECVD” SiN x MIS capacitors. The D it value is obviously higher for the extended wavelength In x Ga 1− x As ( x > 0.53) epitaxial material as a result of lattice mismatch with substrate. Compared to the results of “PECVD” SiN x MIS capacitors, the N si was significantly lower and the N f was slightly lower for “ICPCVD” SiN x MIS capacitors. X-ray photoelectron spectroscopy (XPS) analysis shows good quality of the “ICPCVD” grown SiN x . The low temperature deposited SiN x films grown by “ICPCVD” show better effect on decreasing the dark current of In x Ga 1− x As photodiodes.
Christophe Baley - One of the best experts on this subject based on the ideXlab platform.
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Effect of flax fibres individualisation on tensile failure of flax/epoxy unidirectional composite
Composites Part A-applied Science and Manufacturing, 2013Co-Authors: Guillaume Coroller, Antoine Le Duigou, Gilles Ausias, Thierry Gaudry, Anaële Lefeuvre, Alain Bourmaud, Christophe BaleyAbstract:The study of plant fibres composites is a widespread research topic; nevertheless, the reinforcement mechanism understanding of these materials must be still improved. The paper presents a study of the effect of the mechanical properties, the dispersion and the fibre/matrix Interface Property of elementary fibres on the tensile properties of unidirectional composites. Our work shows that the mechanical performances of unidirectional composites could be linked to those of the elementary fibres as well as to the composites microstructure. Flax fibres individualisation, linked to the homogeneity of the microstructure, is highly dependent on the fibre extraction process. The importance of the composites homogeneity has been confirmed by the Rosen model, which could be used thanks to interfacial shear strength measurements.
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effect of flax fibres individualisation on tensile failure of flax epoxy unidirectional composite
Composites Part A-applied Science and Manufacturing, 2013Co-Authors: Guillaume Coroller, Antoine Le Duigou, Gilles Ausias, Thierry Gaudry, Anaële Lefeuvre, Alain Bourmaud, Christophe BaleyAbstract:The study of plant fibres composites is a widespread research topic; nevertheless, the reinforcement mechanism understanding of these materials must be still improved. The paper presents a study of the effect of the mechanical properties, the dispersion and the fibre/matrix Interface Property of elementary fibres on the tensile properties of unidirectional composites. Our work shows that the mechanical performances of unidirectional composites could be linked to those of the elementary fibres as well as to the composites microstructure. Flax fibres individualisation, linked to the homogeneity of the microstructure, is highly dependent on the fibre extraction process. The importance of the composites homogeneity has been confirmed by the Rosen model, which could be used thanks to interfacial shear strength measurements.
Takahito Ono - One of the best experts on this subject based on the ideXlab platform.
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improved thermal Interface Property of carbon nanotube cu composite based on supercritical fluid deposition
Carbon, 2014Co-Authors: Masaya Toda, Takahito OnoAbstract:Abstract In this paper, we present a new synthesis method of carbon nanotubes (CNTs)-copper (Cu) composite on a silicon substrate using combination of supercritical fluid deposition (SCFD) and electrochemical plating (ECP) process. Deposition of a Cu layer onto CNTs is carried out under supercritical condition, and the CNTs–Cu composite with high-density Cu is synthesized by additional ECP process. The Cu layer deposited by SCFD functions as a seed layer for ECP, and spaces between neighboring CNTs are filled by Cu. The measured density of the CNTs–Cu composite is 8.2 ± 0.3 g/cm3, and the volume percentage of voids is 3–6%. The evaluated thermal resistance including the thermal Interface resistance and bulk resistance of the composite is as low as 28.4 mm2 K W−1 at a contact pressure of 0.2 MPa. A CNT brush formed on the composite surface can reduce the thermal resistance to be 68.4 mm2 K W−1 at a contact pressure of 0.25 MPa. The CNTs–Cu composite shows the ability applicable to many microelectronics applications as a thermal Interface material.
