Effect of Ru crystal phase on the catalytic activity of hydrolytic dehydrogenation of ammonia borane

Chen, Guozhu,Wang, Ruyue,Zhao, Wei,Kang, Baotao,Gao, Daowei,Li, Cuncheng,Lee, Jin Yong Elsevier 2018 Journal of Power Sources Vol.396 No.-

<P><B>Abstract</B></P> <P>Ruthenium (Ru) is one of the most attractive catalysts in the hydrolytic dehygrogenation of ammonia borane. So far, the employed Ru-based catalysts are mainly focusing on hexagonal close packed structured Ru. In this work, we study the crystal phase effect of Ru on the hydrolytic dehygrogenation of ammonia borane, using face-centered cubic structured and hexagonal close packed structured Ru nanoparticles supported on γ-Al<SUB>2</SUB>O<SUB>3</SUB>. The results show that the catalytic activity is different even these two kinds of Ru nanoparticles hold similar size. Impressively, with the Ru particle size change, the variation trend of activity is opposite for face-centered cubic and hexagonal close packed structured Ru/γ-Al<SUB>2</SUB>O<SUB>3</SUB>. Finally, some possible reasons for their difference are proposed based on density functional theory calculations.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The crystal phase effect of Ru on the hydrolysis of ammonia borane was studied. </LI> <LI> The <I>hcp</I> Ru/γ-Al<SUB>2</SUB>O<SUB>3</SUB> exhibits higher activity than that of <I>fcc</I> Ru with similar Ru size. </LI> <LI> The variation trend of activity is opposite with the <I>fcc</I> and <I>hcp</I> Ru size change. </LI> <LI> DFT was used to understand the activity difference between <I>fcc</I> and <I>hcp</I> Ru. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

The investigation of a new fast timing system based on DRS4 waveform sampling system

Jinda Chen,Chengming Du,Jinda Chen,Herun Yang,Jie kong,Haibo Yang,Peng Ma,Guozhu Shi,limin Duan,Zhengguo Hu 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.2

In the study of nuclear structure, the fast timing technique can be used to measure the lifetime of excitedstates. In the paper, we have developed a new fast timing system, which is made up of two LaBr3:Cedetectors and a set of waveform sampling system. The sampling system based on domino ring samplerversion 4 chip (DRS4) can digitize and store the waveform information of detector signal, with a smallervolume and higher timing accuracy, and the waveform data are performed by means of digital waveformanalysis methods. The coincidence time resolution of the fast timing system for two annihilation 511 keVg photon is 200ps (FWHM), the energy resolution is 3.5%@511 keV, and the energy linear response in thelarge dynamic range is perfect. Meanwhile, to verify the fast timing performance of the system, the152Gd-21þ state form bþ decay of 152Eu source is measured. The measured lifetime is 45.3(±5.0)ps, veryclose to the value of the National Nuclear Data Center (NNDC: 46.2((±3.9)ps). The experimental resultsindicate that the fast timing system is capable of measuring the lifetime of dozens of ps. Therefore, thesystem can be widely used in the research of the fast timing technology.

A Novel Modulation Scheme and a DC-Link Voltage Balancing Control Strategy for T-Type H-Bridge Cascaded Multilevel Converters

Wang, Yue,Hu, Yaowei,Chen, Guozhu The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.6

The cascaded multilevel converter is widely adopted to medium/high voltage and high power electronic applications due to the small harmonic components of the output voltage and the facilitation of modularity. In this paper, the operation principle of a T-type H-bridge topology is investigated in detail, and a carrier phase shifted pulse width modulation (CPS-PWM) based control method is proposed for this topology. Taking a virtual five-level waveform achieved by a unipolar double frequency CPS-PWM as the output object, PWM signals of the T-type H-bridge can be obtained by reverse derivation according to its switching modes. In addition, a control method for the T-type H-bridge based cascaded multilevel converter is introduced. Then a single-phase T-type H-bridge cascaded multilevel static var generator (SVG) prototype is built, and a repetitive controller based compound current control strategy is designed with the DC-link voltage balancing control scheme analyzed. Finally, simulation and experimental results validate the correctness and feasibility of the proposed modulation method and control strategy for T-type H-bridge based cascaded multilevel converters.

Design and Research on High-Reliability HPEBB Used in Cascaded DSTATCOM

Yang, Kun,Wang, Yue,Chen, Guozhu The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.3

The H-bridge inverter is the fundamental power cell of the cascaded distribution static synchronous compensator (DSTATCOM). Thus, cell reliability is important to the compensation performance and stability of the overall system. The concept of the power electronics building block (PEBB) is an ideal solution for the power cell design. In this paper, an H-bridge inverter-based “plug and play” HPEBB is introduced into the main circuit and the controller to improve the compensation performance and reliability of the device. The section that discusses the main circuit primarily emphasizes the design of electrical parameters, physical structure, and thermal dissipation. The section that presents the controller part focuses on the principle of complex programmable logic device -based universal controller This section also analyzes typical reliability and anti-interference issues. The function and reliability of HPEBB are verified by experiments that are conducted on an HPEBB test-bed and on a 10 kV/± 10 Mvar DSTATCOM industrial prototype.

Implementation of a No Pulse Competition CPS-SPWM Technique Based on the Concentrated Control for Cascaded Multilevel DSTATCOMs

Wang, Yue,Yang, Kun,Chen, Guozhu The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

Digital signal processor (DSP) and field programmable gate array (FPGA) based concentrated control systems are designed for implementing CPS-SPWM strategies. The self-defined universal asynchronous receiver/transmitter (UART) protocol is used for communication between a master controller and an individual module controller via high speed links. Aimed at undesired pulse competition, this paper analyzes its generation mechanism and presents a new method for eliminating competition pulses with no time delay. Finally, the proposed concentrated controller is applied to a 10kV/10MVar distribution static synchronous compensator (DSTATCOM) industrial prototype. Experimental results show the accuracy and reliability of the concentrated controller, and verify the superiority of the proposed elimination method for competition pulses.

Design and Research on High-Reliability HPEBB Used in Cascaded DSTATCOM

Kun Yang,Yue Wang,Guozhu Chen 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.3

The H-bridge inverter is the fundamental power cell of the cascaded distribution static synchronous compensator (DSTATCOM). Thus, cell reliability is important to the compensation performance and stability of the overall system. The concept of the power electronics building block (PEBB) is an ideal solution for the power cell design. In this paper, an H-bridge inverter-based “plug and play” HPEBB is introduced into the main circuit and the controller to improve the compensation performance and reliability of the device. The section that discusses the main circuit primarily emphasizes the design of electrical parameters, physical structure, and thermal dissipation. The section that presents the controller part focuses on the principle of complex programmable logic device -based universal controller This section also analyzes typical reliability and anti-interference issues. The function and reliability of HPEBB are verified by experiments that are conducted on an HPEBB test-bed and on a 10 kV/± 10 Mvar DSTATCOM industrial prototype.

A Novel Modulation Scheme and a DC-Link Voltage Balancing Control Strategy for T-Type H-Bridge Cascaded Multilevel Converters

Yue Wang,Yaowei Hu,Guozhu Chen 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.6

The cascaded multilevel converter is widely adopted to medium/high voltage and high power electronic applications due to the small harmonic components of the output voltage and the facilitation of modularity. In this paper, the operation principle of a T-type H-bridge topology is investigated in detail, and a carrier phase shifted pulse width modulation (CPS-PWM) based control method is proposed for this topology. Taking a virtual five-level waveform achieved by a unipolar double frequency CPS-PWM as the output object, PWM signals of the T-type H-bridge can be obtained by reverse derivation according to its switching modes. In addition, a control method for the T-type H-bridge based cascaded multilevel converter is introduced. Then a single-phase T-type H-bridge cascaded multilevel static var generator (SVG) prototype is built, and a repetitive controller based compound current control strategy is designed with the DC-link voltage balancing control scheme analyzed. Finally, simulation and experimental results validate the correctness and feasibility of the proposed modulation method and control strategy for T-type H-bridge based cascaded multilevel converters.

Implementation of a No Pulse Competition CPS-SPWM Technique Based on the Concentrated Control for Cascaded Multilevel DSTATCOMs

Yue Wang,Kun Yang,Guozhu Chen 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

Digital signal processor (DSP) and field programmable gate array (FPGA) based concentrated control systems are designed for implementing CPS-SPWM strategies. The self-defined universal asynchronous receiver/transmitter (UART) protocol is used for communication between a master controller and an individual module controller via high speed links. Aimed at undesired pulse competition, this paper analyzes its generation mechanism and presents a new method for eliminating competition pulses with no time delay. Finally, the proposed concentrated controller is applied to a 10kV/10MVar distribution static synchronous compensator (DSTATCOM) industrial prototype. Experimental results show the accuracy and reliability of the concentrated controller, and verify the superiority of the proposed elimination method for competition pulses.

A Load Compensator Based on One-Cycle Control with Plug-In Repetitive Control

Jian Hu,Zhaohui Sun,Hao Ma,Guozhu Chen 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

This study proposes a novel one-cycle control scheme with a plug-in repetitive controller for load compensator. The novelty of this scheme lies in the combination of high dynamics and the simplicity of a one-cycle controller and good steady-state harmonic suppression ability of the repetitive controller. In addition, the proposed scheme can reduce the effect of the harmonics in phase voltage for the existence of the repetitive controller. Finally, experimental results on a three-phase, four-wire, three-level load compensator are reported to validate the effectiveness of the proposed control scheme.

A Load Compensator Based on One-Cycle Control with Plug-In Repetitive Control

Hu, Jian,Sun, Zhaohui,Ma, Hao,Chen, Guozhu The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

This study proposes a novel one-cycle control scheme with a plug-in repetitive controller for load compensator. The novelty of this scheme lies in the combination of high dynamics and the simplicity of a one-cycle controller and good steady-state harmonic suppression ability of the repetitive controller. In addition, the proposed scheme can reduce the effect of the harmonics in phase voltage for the existence of the repetitive controller. Finally, experimental results on a three-phase, four-wire, three-level load compensator are reported to validate the effectiveness of the proposed control scheme.