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Stretchable Binary Fresnel Lens for Focus Tuning

Li, X. (author), Wei, L. (author), Poelma, René H. (author), Vollebregt, S. (author), Wei, J. (author), Urbach, Paul (author), Sarro, Pasqualina M (author), Zhang, Kouchi (author)

This paper presents a tuneable binary amplitude Fresnel lens produced by wafer-level microfabrication. The Fresnel lens is fabricated by encapsulating lithographically defined vertically aligned carbon nanotube (CNT) bundles inside a polydimethyl-siloxane (PDMS) layer. The composite lens material combines the excellent optical absorption...

journal article 2016

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Evaluating degradation at railway crossings using axle box acceleration measurements

Wei, Z. (author), Nunez, Alfredo (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)

In this paper, we investigate the capability of an axle box acceleration (ABA) system to evaluate the degradation at railway crossings. For this purpose, information from multiple sensors, namely, ABA signals, 3D rail profiles, Global Positioning System (GPS) and tachometer recordings, was collected from both nominal and degraded crossings....

journal article 2017

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Method for evaluating the performance of railway crossing rails after long-term service

Wei, Z. (author), Nunez, Alfredo (author), Boogaard, M.A. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

In this paper, we present a method for evaluating the performance of railway crossing rails after long-term service. The method includes 1) 3D profile and hardness measurements; 2) finite element simulation of wheel/rail interaction; and 3) numerical prediction of rail degradation. We conducted a case study on a crossing that had been in service...

journal article 2018

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An integrated approach for characterizing the dynamic behaviour of wheel-rail interaction at crossings

Wei, Z. (author), Boogaard, M.A. (author), Nunez, Alfredo (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)

This paper describes an approach for characterizing the dynamic behavior of the vehicle/track interaction at railway crossings. In the approach, we integrate in situ axle box acceleration (ABA) measurements with roving-accelerometer hammer tests to evaluate the influence of train speed, train moving direction (facing and trailing directions),...

journal article 2018

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Numerical study of wheel-rail impact contact solutions at an insulated rail joint

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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Risk analysis of earth-rock dam breach based on dynamic Bayesian network

Li, Zongkun (author), Wang, Te (author), Ge, W. (author), Wei, Dong (author), Li, Hanyu (author)

Despite the fact that the Bayesian network has great advantages in logical reasoning and calculation compared with the other traditional risk analysis methods, there are still obvious shortcomings in the study of dynamic risk. The risk factors of the earth-rock dam breach are complex, which vary with time during the operation period. Static...

journal article 2019

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Abundant grain boundaries activate highly efficient lithium ion transportation in high rate Li₄Ti₅O₁₂ compact microspheres

Ma, Jiaming (author), Wei, Yinping (author), Gan, Lin (author), Wang, C. (author), Xia, Heyi (author), Lv, Wei (author), Li, Jia (author), Li, Baohua (author), Yang, Quan Hong (author), Kang, Feiyu (author), He, Yan Bing (author)

It is a huge challenge for high-tap-density electrodes to achieve high volumetric energy density but without compromising the ionic transportation. Herein, we prepared compact Li₄Ti₅O₁₂ (LTO) microspheres consisting of densely packed primary nanoparticles. The real space distribution of lithium ions inside the...

journal article 2019

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Physical metallurgy-guided machine learning and artificial intelligent design of ultrahigh-strength stainless steel

Shen, Chunguang (author), Wang, Chenchong (author), Wei, Xiaolu (author), Li, Yong (author), van der Zwaag, S. (author), Xu, W. (author)

With the development of the materials genome philosophy and data mining methodologies, machine learning (ML) has been widely applied for discovering new materials in various systems including high-end steels with improved performance. Although recently, some attempts have been made to incorporate physical features in the ML process, its...

journal article 2019

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Optimization of mesa etch for a quasi-vertical gan schottky barrier diode (Sbd) by inductively coupled plasma (icp) and device characteristics

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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Multi-criteria evaluation of wheel/rail degradation at railway crossings

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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Comparisons between beam and continuum models for modelling wheel-rail impact at a singular rail surface defect

Shen, C. (author), Deng, X. (author), Wei, Z. (author), Dollevoet, R.P.B.J. (author), Zoeteman, A. (author), Li, Z. (author)

A singular rail or wheel surface irregularity, such as a squat, insulation joint or wheel flat, can cause large wheelrail impact force. Both the magnitude and frequency content of the impact force need to be correctly modelledbecause they are closely related to the formation, deterioration and detection of such irregularities. In this paper,we...

journal article 2021

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Comparative study of low-cost fluoride removal by layered double hydroxides, geopolymers, softening pellets and struvite

Wei, L. (author), Li, Z. (author), Ye, G. (author), Rietveld, L.C. (author), van Halem, D. (author)

Excessive F^- in drinking water due to natural and anthropogenic activities is a serious health hazard affecting humans worldwide. In this study, a comparative assessment was made of eight mineral-based materials with advantageous structural properties for F^- uptake: layered-double-hydroxides (LDHs), geopolymers,...

journal article 2021

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Laboratory data on wave propagation through vegetation with following and opposing currents

Hu, Zhan (author), Lian, Simei (author), Wei, Huaiyu (author), Li, Yulong (author), Stive, M.J.F. (author), Suzuki, T. (author)

Coastal vegetation has been increasingly recognized as an effective buffer against wind waves. Recent laboratory studies have considered realistic vegetation traits and hydrodynamic conditions, which advanced our understanding of the wave dissipation process in vegetation (WDV) in field conditions. In intertidal environments, waves commonly...

journal article 2021

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PrivGait: An Energy Harvesting-based Privacy-Preserving User Identification System by Gait Analysis

Xu, Weitao (author), Xue, Wanli (author), Lin, Qi (author), Lan, G. (author), Feng, Xingyu (author), Wei, Bo (author), Luo, Chengwen (author), Li, Wei (author), Zomaya, Albert Y. (author)

Smart space has emerged as a new paradigm that combines sensing, communication, and artificial intelligence technologies to offer various customized services. A fundamental requirement of these services is person identification. Although a variety of person-identification approaches has been proposed, they suffer from several limitations in...

journal article 2022

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Machine learning-enabled high-entropy alloy discovery

Rao, Ziyuan (author), Tung, Po Yen (author), Xie, Ruiwen (author), Wei, Ye (author), Ferrari, A. (author), Klaver, T.P.C. (author), Körmann, F.H.W. (author), Li, Zhiming (author), Bauer, Stefan (author), Raabe, Dierk (author)

High-entropy alloys are solid solutions of multiple principal elements that are capable of reaching composition and property regimes inaccessible for dilute materials. Discovering those with valuable properties, however, too often relies on serendipity, because thermodynamic alloy design rules alone often fail in high-dimensional composition...

journal article 2022

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Unraveling electron liberation from Bi²⁺ for designing Bi³⁺-based afterglow phosphor for anti-counterfeiting and flexible X-ray imaging

Lyu, T. (author), Dorenbos, P. (author), Li, Canhua (author), Li, Silei (author), Xu, Jian (author), Wei, Zhanhua (author)

It is challenging to rational design persistent luminescence and storage phosphors with high storage capacity of electrons and holes after X-ray charging. Such phosphors have potential applications in anti-counterfeiting and X-ray imaging. Here we have combined vacuum referred binding energy diagram (VRBE) construction, photoluminescence...

journal article 2022

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Error Features in Predicting Typhoon Winds: A Case Study Comparing Simulated and Measured Data

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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Ground vibration induced by high speed trains on an embankment with pile-board foundation: Modelling and validation with in situ tests

Wang, L. (author), Wang, Ping (author), Wei, Kai (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

To investigate the train-induced ground vibration, an explicit time-domain, three dimensional (3D) finite element (FE) model is developed. The train, track, embankment, pile-board structure and nearby ground soils are all fully coupled in this model. The complex geometries involving the track components and pile-board structure are all...

journal article 2022

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Simulation of Poyang Lake water levels and outflow under historical extreme hydrological scenarios

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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Wide Range X-Ray to Infrared Photon Detection and Energy Storage in LiTaO₃:Bi³⁺,Dy³⁺ Perovskite

Lyu, Tianshuai (author), Dorenbos, P. (author), Li, Canhua (author), Wei, Zhanhua (author)

It is challenging to obtain a material that can detect photons ranging from X-rays to infrared light. Such materials have promising use to develop advanced applications like in information storage, anticounterfeiting, or X-ray imaging. This article reports on such a material; LiTaO₃:xBi³⁺,yDy³⁺ perovskite...

journal article 2022