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Wei, J. (author), Chen, Z.L. (author), Liu, Z.W. (author), Sarro, P.M. (author)This paper presents a silicon MEMS capacitive structure to investigate a test methodology for fF-level capacitive sensors’ measurement. The device mimics a capacitive sensor with a changing intermediate layer between the electrodes. A single mask bulk micromachining process is used to fabricate the device, which has a nominal capacitance of 1.2...journal article 2010
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Luo, Y.C. (author), Liu, X.X. (author), Hayton, D.J. (author), Wei, L. (author), Gao, J.R. (author), Groppi, C. (author)A Fourier phase grating mirror will be applied to split a single, coherent terahertz source beam into multi-beams, which are spatially distributed as required for the local oscillator in an array receiver. We report on the simulation, design and fabrication of a Fourier phase grating at 1.25 THz for generating 2×2 beams, and the measurements at...conference paper 2015
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Liu, X.X. (author), Hayton, D.J. (author), Luo, Y.C. (author), Wei, L. (author), Vercruyssen, N. (author), Gao, J.R. (author), Groppi, C. (author)We report on realization of a 2 × 2 NbN hot electron bolometer (HEB) array receiver using multiple local oscillator (LO) beams that are obtained from a Fourier phase grating mirror. The grating splits a 1.4 THz single beam into four uniform sub-beams. Two 50mm lenses are applied to collimate each beam in order to achieve a spacing of 12mm...conference paper 2015
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Mirzaei, B. (author), Silva, J. R.G. (author), Luo, Y. (author), Liu, X. X. (author), Wei, L. (author), Hayton, Darren J. (author), Gao, J.R. (author), Groppi, C (author)We compare the results of simulated and measured power efficiency and far-field beam pattern, for two reflective Fourier phase gratings, designed to generate 2 x 2 and 2 x 4 beams respectively from a single-beam, coherent source at 1.4 THz. The designed surface structures were manufactured on aluminum plates by a computer numerical control ...journal article 2017
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Yang, Z. (author), Boogaard, M.A. (author), Wei, Z. (author), Liu, Jinzhao (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)This paper presents an analysis of the transient contact solutions of wheel-rail frictional rolling impacts calculated by an explicit finite element model of the wheel-insulated rail joint (IRJ) dynamic interaction. The ability of the model to simulate the dynamic behavior of an IRJ has been validated against a comprehensive field measurement in...journal article 2018
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Sun, Y. (author), Kang, Xuanwu (author), Zheng, Yingkui (author), Lu, Jiang (author), Tian, Xiaoli (author), Wei, Ke (author), Wu, Hao (author), Wang, Wenbo (author), Liu, Xinyu (author), Zhang, Kouchi (author)Gallium nitride (GaN)-based vertical power Schottky barrier diode (SBD) has demonstrated outstanding features in high-frequency and high-power applications. This paper reviews recent progress on GaN-based vertical power SBDs, including the following sections. First, the benchmark for GaN vertical SBDs with different substrates (Si, sapphire, and...review 2019
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Zhang, Chunyan (author), Liu, Bin (author), Yu, Baoxing (author), Lu, Xiaopeng (author), Wei, Yong (author), Zhang, Tao (author), Mol, J.M.C. (author), Wang, Fuhui (author)Surface pretreatment is generally applied before application of protective coatings on Mg alloys, which influences surface microstructure and electrochemical activity of the substrate and has an effect on the coating properties. The effect of various pretreatment processes (sand-blasting, grinding and polishing) on the microstructure and...journal article 2019
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Sun, Y. (author), Kang, Xuanwu (author), Zheng, Yingkui (author), Wei, Ke (author), Li, Pengfei (author), Wang, Wenbo (author), Liu, Xinyu (author), Zhang, Kouchi (author)The optimization of mesa etch for a quasi-vertical gallium nitride (GaN) Schottky barrier diode (SBD) by inductively coupled plasma (ICP) etching was comprehensively investigated in this work, including selection of the etching mask, ICP power, radio frequency (RF) power, ratio of mixed gas, flow rate, and chamber pressure, etc. In particular...journal article 2020
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Wei, Z. (author), Nunez, Alfredo (author), Liu, Xiubo (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)This study evaluates the degradation of wheels and rails at railway crossings. The evaluation method is composed of 1) finite element simulation of dynamic wheel/crossing interaction and 2) multi-criteria analysis of wheel/rail degradation in terms of yield behavior, rolling contact fatigue (RCF) and wear. With the aid of this method, we...journal article 2020
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Liu, Yangqing (author), Liu, Yuqing (author), Xin, H. (author), Tian, Hao (author), Wei, Jun (author)To improve the shear behavior and design applicability of rubber ring perfobond connectors (RPBLs), a new rubber ring that aims to make the shear stiffness of RPBLs controllable was proposed. Firstly, the conceptual design and configuration of the new rubber rings were presented and discussed. Subsequently, finite element (FE) models for...journal article 2020
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Sun, Y. (author), Kang, Xuanwu (author), Deng, Shixiong (author), Zheng, Yingkui (author), Wei, Ke (author), Xu, Linwang (author), Wu, Hao (author), Liu, Xinyu (author)Gallium nitride (GaN) has attracted increased attention because of superior material properties, such as high electron saturation velocity and high electrical field strength, which are promising for high-power microwave applications. We report on a high-performance vertical GaN-based Schottky barrier diode (SBD) and its demonstration in a...journal article 2021
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Kang, Xuanwu (author), Sun, Y. (author), Zheng, Yingkui (author), Wei, Ke (author), Wu, Hao (author), Zhao, Yuanyuan (author), Liu, Xinyu (author), Zhang, Kouchi (author)In this brief, a high-performance quasi-vertical GaN Schottky barrier diode (SBD) on sapphire substrate with post-mesa nitridation process is reported, featuring a low damaged sidewall with extremely low leakage current. The fabricated SBD with a drift layer of 1 μm has achieved a very high ON/OFF current ratio (Iscriptscriptstyle ON...journal article 2021
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Sun, Y. (author), Kang, Xuanwu (author), Deng, Shixiong (author), Zheng, Yingkui (author), Wei, Ke (author), Xu, Linwang (author), Wu, Hao (author), Liu, Xinyu (author)We report a high-performance GaN Schottky barrier diode (SBD) on a sapphire substrate with a novel post-mesa nitridation technique and its application in a high-power microwave detection circuit. The fabricated SBD achieved a very high forward current density of 9.19 kA cm-2 at 3 V, a low specific on-resistance (RON,sp) of 0.22 mO cm2 and...journal article 2021
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Wu, Xintong (author), Huang, Haoliang (author), Liu, Hao (author), Hu, Jie (author), Wei, Jiangxiong (author), Jiang, Zhengwu (author), Ye, G. (author), Yu, Qijun (author), Lothenbach, Barbara (author)New self-healing agents that can chemically bind seawater ions invading cracked cementitious materials were proposed. The potential of self-healing and binding of seawater ions were investigated by thermodynamic modeling. It was found that CaO-NaAlO<sub>2</sub> and CaO-metakaolin agents can have Cl<sup>−</sup>, SO<sub>4</sub><sup>2−</sup> and...journal article 2021
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Wu, Xintong (author), Huang, Haoliang (author), Liu, Hao (author), Hu, Jie (author), Wei, Jiangxiong (author), Yu, Qijun (author)In this study, a new concept on self healing of cracks that the ingressive ions in the crack is chemically bound to improve the self-healing efficiency was proposed for cracked cementitious materials in a marine environment. Thermodynamic modeling was performed to determine the appropriate masses and ratio of Ca2+ and Al3+ provided by chemical...conference paper 2021
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Peng, Shaoyuan (author), Liu, Y. (author), Li, Renge (author), Wei, Ying (author), Chan, Pak Wai (author), Li, Sunwei (author)Simulating a typhoon’s wind field via mesoscale models is important in terms of providing not only the guidelines for urban planning and onshore/offshore constructions, but also the provision of insight into the dynamics and thermodynamics of tropical cyclone systems. Therefore, the errors that are contained in simulation results were...journal article 2022
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Yu, M. (author), Liu, X. (author), Wood, Paul (author), Wei, Li (author), Wang, Guoqing (author), Zhang, Jianyun (author), Li, Qiongfang (author)Due to an intensification of anthropogenic activities and climate change in recent decades, the hydrological connections and relationships between rivers and lakes have been significantly modified globally. Poyang Lake is one of the largest freshwater lakes globally and is one of the few that remain naturally connected to the Yangtze River....journal article 2022
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Gao, Shibin (author), He, Zonglun (author), Wei, Xiaoguang (author), Liu, Y. (author), Huang, Tao (author), Lei, Jieyu (author)A topology attack, as a special class of false data injection attacks, tampers with topology information of a system to mislead the decision of the control center. This article conducts an in-depth study on topology attacks that aim to interfere with the judgment in topology information and pose potential damage by tampering with measurement...journal article 2022
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Liu, Mingqiang (author), Zhu, Yongsong (author), Wei, Jianjun (author), Le, Yun (author), Zhang, X. (author)External program manager involvement can provide professional and systematic management services to owners. It can help to manage and coordinate different subprojects and ensure the achievement of the overall strategic goals of large projects. The promotion of external program manager involvement is not only efficiency-driven, but the...journal article 2022
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Tan, C. (author), Wang, S. (author), Li, Shizhen (author), Liu, X. (author), Wei, Jia (author), Zhang, Kouchi (author), Ye, H. (author)Owing to the outstanding physical properties of graphene, its biosensing applications implemented by the terahertz metasurface are widely concerned and studied. Here, we present a novel design of the graphene metasurface, which consists of an individual graphene ring and an H-shaped graphene structure. The graphene metasurface exhibits a dual...journal article 2022
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