Hung Yen University of Technology and Education

About: Hung Yen University of Technology and Education is a education organization based out in Hưng Yên, Vietnam. It is known for research contribution in the topics: Engineering & Computer science. The organization has 189 authors who have published 291 publications receiving 1904 citations.

Gas-sensing properties of tin oxide doped with metal oxides and carbon nanotubes: A competitive sensor for ethanol and liquid petroleum gas

Abstract: SnO2 doped with metal oxides such as PtO2, PdO, La2O3 CuO, and Fe2O3 and multi-walled carbon nanotubes (MWCNTs) thin films were prepared by the sol–gel method. Thin film gas sensors were fabricated by spin-coating the sol onto interdigitated microelectrodes. The microstructure and morphology of the materials were characterized by XRD, FE-SEM, and TEM. The results reveal that their SnO2 particle size is lower than 10 nm, and the MWCNTs doping is well embedded in the SnO2 matrix. The response of all the sensors was studied for different concentrations of ethanol and liquid petroleum gases (LPG) and at different operating temperatures. Comparative results reveal that the (1 wt%) PtO2-doped SnO2 sensor exhibits higher sensitivity to ethanol gas and LPG than the sensors doped with the other dopants. Especially, the (1 wt%) PtO2-doped SnO2 sensor shows higher selectivity to ethanol gas over LPG, while the (0.1 wt%, 20

Thin film polypyrrole/SWCNTs nanocomposites- based NH3 sensor operated at room temperature

Abstract: A PPY/SWCNTs nanocomposite-based sensor with relatively high sensitivity and fast response–recovery was developed for detection of NH3 gas at room temperature. The gas-sensitive composite thin film was prepared using chemical polymerization and spin-coating techniques, and characterized by Fourier transformed infrared spectra and field-emission scanning electron microscopy. The results reveal that the conjugated structure of the PPY layer was formed and the functionalized SWCNTs were well-embedded. The effects of film thickness, annealing temperature, and SWCNTs content on gas-sensing properties of the composite thin film were investigated to optimize the gas-sensing performance. The as-prepared thin film PPY/SWCNTs composite sensor with optimized process parameters had a response of 26–276% upon exposure to NH3 gas concentration from 10 to 800 ppm, and their response and recovery times were around 22 and 38 s, respectively.

Study of a Current Control Strategy Based on Multisampling for High-Power Grid-Connected Inverters With an LCL filter

Abstract: The high-power grid-connected inverters with LCL filters have been widely used. Current control plays a key role in the grid-connected inverter control system. To cope with the inherent resonance of the LCL filter, active damping (AD) methods are usually employed. However, the AD performance is impaired by control delays which are introduced in the digital control implementation process. Besides, the lag phase due to control delays limits the system bandwidth and stability margin. The effects of control delays are more noteworthy in the high-power grid-connected inverter due to its low switching frequency. This paper investigates the current control strategy based on multisampling for the high-power grid-connected inverter with the LCL filter. First, the multisampled AD scheme is studied, which can reduce control delays effectively and improve AD performance. Besides, the multisampled control without additional damping whether passive or active is researched. Through the inverter-side current feedback, the system can realize single-current-loop control based on multisampling. Thus, the control system is simplified and it can be stable, and achieve better dynamic performance. Finally, experimental results show that the proposed control schemes are effective.