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Investigating self-healing capacity of micro-cracked ECC with different volume of fly ash

Zhang, Z. (author), Qian, S. (author)

Crack is called the intrinsic flaw of concrete that is inevitable for concrete infrastructures during their service life. The presence of crack offer aggressive agent access to pass through, which has a direct impact on durability, therefore resulting in shortened service life. Nevertheless, the influence of crack on the durability can be...

conference paper 2013

document

Interaction between microcapsules and cementitious matrix after cracking in a self-healing system

Wang, X. (author), Xing, F. (author), Zhang, M. (author), Han, N. (author), Qian, Z. (author)

A new type of self-healing cementitious composites by using organic microcapsules is designed in Guangdong Key Laboratory of Durability for Coastal Civil Engineering, Shenzhen University. For the organic microcapsules, the shell material is urea formoldehyde (UF), and the core healing agent is Epoxy. The effect of organic microcapsules on...

conference paper 2013

document

Interaction between microcapsules and cementitious matrix after cracking in a self-healing system

Wang, X. (author), Xing, F. (author), Zhang, M. (author), Han, N. (author), Qian, Z. (author)

A new type of self-healing cementitious composites by using organic microcapsules is designed in Guangdong Key Laboratory of Durability for Coastal Civil Engineering, Shenzhen University. For the organic microcapsules, the shell material is urea formoldehyde (UF), and the core healing agent is Epoxy. The effect of organic microcapsules on...

conference paper 2013

document

Experimental Study on Cementitious Composites Embedded with Organic Microcapsules

Wang, X. (author), Xing, F. (author), Zhang, M. (author), Han, N. (author), Qian, Z. (author)

The recovery behavior for strength and impermeability of cementitious composites embedded with organic microcapsules was investigated in this study. Mortar specimens were formed by mixing the organic microcapsules and a catalyst with cement and sand. The mechanical behaviors of flexural and compression strength were tested. The results showed...

journal article 2013

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Color Shift Failure Prediction for Phosphor-Converted White LEDs by Modeling Features of Spectral Power Distribution with a Nonlinear Filter Approach

Fan, Jiajie (author), Mohamed, Moumouni Guero (author), Qian, Cheng (author), Fan, Xuejun (author), Zhang, Kouchi (author), Pecht, Micheal (author)

With the expanding application of light-emitting diodes (LEDs), the color quality of white LEDs has attracted much attention in several color-sensitive application fields, such as museum lighting, healthcare lighting and displays. Reliability concerns for white LEDs are changing from the luminous efficiency to color quality. However, most of the...

journal article 2017

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Dual-action smart coatings with a self-healing superhydrophobic surface and anti-corrosion properties

Qian, Hongchang (author), Xu, Dake (author), Du, Cuiwei (author), Zhang, Dawei (author), Li, Xiaogang (author), Huang, Luyao (author), Deng, Leping (author), Tu, Yunchao (author), Mol, J.M.C. (author), Terryn, H.A. (author)

This work introduces a new self-healing superhydrophobic coating based on dual actions by the corrosion inhibitor benzotriazole (BTA) and an epoxy-based shape memory polymer (SMP). Damage to the surface morphology (e.g., crushed areas and scratches) and the corresponding superhydrophobicity are shown to be rapidly healed through a simple heat...

journal article 2017

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Photometric and colorimetric assessment of LED chip scale packages by using a step-stress accelerated degradation test (SSADT) method

Qian, Cheng (author), Fan, Jiajie (author), Fang, Jiayi (author), Yu, Chaohua (author), Ren, Y. (author), Fan, Xuejun (author), Zhang, Kouchi (author)

By solving the problem of very long test time on reliability qualification for Light-emitting Diode (LED) products, the accelerated degradation test with a thermal overstress at a proper range is regarded as a promising and effective approach. For a comprehensive survey of the application of step-stress accelerated degradation test (SSADT) in...

journal article 2017

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Prediction of Lumen Depreciation and Color Shift for Phosphor-Converted White Light-Emitting Diodes Based on A Spectral Power Distribution Analysis Method

Qian, Cheng (author), Fan, Jiajie (author), Fan, Xuejun (author), Zhang, Kouchi (author)

The spectral power distribution (SPD) is considered as the figureprint of a light emitting diode (LED). Based on the analysis on its SPD, a method to predict both lumen depreciation and color shift for the phosphor converted white LEDs (pc-LEDs) is proposed in this paper. First, the entire SPD of a pc-LED is predicted by superimposing two...

journal article 2017

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A PoF and statistics combined reliability prediction for LED arrays in lamps

Sun, B. (author), Fan, Xuejun (author), Fan, J. (author), Zhang, Kouchi (author), Qian, Cheng (author)

In this work, a physics-of-failure (PoF) reliability prediction methodology is combined with statistical models to consider the interaction between the lumen depreciation and catastrophic failures of LEDs. The current in each LED may redistribute when the catastrophic failure occurs in one of LEDs in an array, thus affecting the operation...

conference paper 2017

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A novel lifetime prediction for integrated LED lamps by electronic-thermal simulation

Sun, B. (author), Fan, Xuejun (author), Ye, H. (author), Fan, Jiajie (author), Qian, Cheng (author), van Driel, W.D. (author), Zhang, Kouchi (author)

In this paper, an integrated LED lamp with an electrolytic capacitor-free driver is considered to study the coupling effects of both LED and driver's degradations on lamp's lifetime. An electrolytic capacitor-less buck-boost driver is used. The physics of failure (PoF) based electronic thermal simulation is carried out to simulate the lamp's...

journal article 2017

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Numerical thermal analysis and optimization of multi-chip LED module using response surface methodology and genetic algorithm

Tang, H. (author), Ye, Huai-Yu (author), Chen, Xian-Ping (author), Qian, Cheng (author), Fan, Xue-Jun (author), Zhang, Kouchi (author)

In this paper, the heat transfer performance of the multi-chip (MC) LED module is investigated numerically by using a general analytical solution. The configuration of the module is optimized with genetic algorithm (GA) combined with a response surface methodology. The space between chips, the thickness of the metal core printed circuit board...

journal article 2017

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Experimental study on mechanical behavior of shear connectors of square concrete filled steel tube

Qiao, Qiyun (author), Zhang, Wenwen (author), Qian, Zhiwei (author), Cao, Wanlin (author), Liu, Wenchao (author)

In order to quantitatively evaluate the shear-bearing capacity of shear connectors of square concrete filled steel tube (CFST), push-out tests on 14 square CFSTs with shear connectors have been carried out. Among the 14 CFSTs, there are 13 specimens with steel plate connectors and one specimen with steel bar connectors. The following factors...

journal article 2017

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Cyclic behavior of low rise concrete shear walls containing recycled coarse and fine aggregates

Qiao, Qiyun (author), Cao, Wanlin (author), Qian, Zhiwei (author), Li, Xiangyu (author), Zhang, Wenwen (author), Liu, Wenchao (author)

In this study, the cyclic behaviors of low rise concrete shear walls using recycled coarse or fine aggregates were investigated. Eight low rise Recycled Aggregates Concrete (RAC) shear wall specimens were designed and tested under a cyclic loading. The following parameters were varied: replacement percentages of recycled coarse or fine...

journal article 2017

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Triple-action self-healing protective coatings based on shape memory polymers containing dual-function microspheres

Huang, Yao (author), Deng, Leping (author), Ju, Pengfei (author), Huang, Luyao (author), Qian, H. (author), Zhang, Dawei (author), Li, Xiaogang (author), Terryn, H.A. (author), Mol, J.M.C. (author)

In this study, a new self-healing shape memory polymer (SMP) coating was prepared to protect the aluminum alloy 2024-T3 from corrosion by the incorporation of dual-function microspheres containing polycaprolactone and the corrosion inhibitor 8-hydroxyquinoline (8HQ). The self-healing properties of the coatings were investigated via scanning...

journal article 2018

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Thermal Management on IGBT Power Electronic Devices and Modules

Qian, C. (author), Mirza Gheytaghi, Amir (author), Fan, J. (author), Tang, H. (author), Sun, B. (author), Ye, H. (author), Zhang, Kouchi (author)

As an increasing attention towards sustainable development of energy and environment, the power electronics (PEs) are gaining more and more attraction on various energy systems. The insulated gate bipolar transistor (IGBT), as one of the PEs with numerous advantages and potentials for development of higher voltage and current ratings, has been...

journal article 2018

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Reliability Assessment of Light-Emitting Diode Packages with Both Luminous Flux Response Surface Model and Spectral Power Distribution Method

Chen, Wei (author), Fan, J. (author), Qian, Cheng (author), Pu, Bin (author), Fan, Xuejun (author), Zhang, Kouchi (author)

The inherent luminous characteristics and stability of LED packages during the operation period are highly dependent on their junction temperatures and driving currents. In this paper, the luminous flux of LED packages operated under a wide range of driving currents and junction temperatures are investigated to develop a luminous flux...

journal article 2019

document

Switching the magnetostructural coupling in MnCoGe-based magnetocaloric materials

Miao, Xuefei (author), Gong, Yong (author), Caron, Luana (author), You, Yurong (author), Xu, Guizhou (author), Sheptyakov, Denis (author), Manuel, Pascal (author), Qian, Fengjiao (author), Zhang, Yujing (author), Xu, Feng (author), van Dijk, N.H. (author), Brück, E.H. (author)

We performed neutron-diffraction experiments and density functional theory calculations to study the magnetostructural coupling in MnCoGeBx (x=0, 0.01, and 0.05) alloys. By varying the amount of boron addition, we are able to freely switch the magnetostructural coupling on and off in the MnCoGe alloys. It is found that the boron addition...

journal article 2020

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Machine-Learning Assisted Prediction of Spectral Power Distribution for Full-Spectrum White Light-Emitting Diode

Fan, J. (author), Li, Yutong (author), Fryc, Irena (author), Qian, C. (author), Fan, X. (author), Zhang, Kouchi (author)

The full-spectrum white light-emitting diode (LED) emits light with a broad wavelength range by mixing all lights from multiple LED chips and phosphors. Thus, it has great potentials to be used in healthy lighting, high resolution displays, plant lighting with higher color rendering index close to sunlight and higher color fidelity index. The...

journal article 2020

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Design of a Fan-Out Panel-Level SiC MOSFET Power Module Using Ant Colony Optimization-Back Propagation Neural Network

Qian, Yichen (author), Hou, F. (author), Fan, J. (author), Lv, Quanya (author), Fan, X. (author), Zhang, Kouchi (author)

A new panel-level silicon carbide (SiC) metal oxide semiconductor field effect transistor (MOSFET) power module was developed by using the fan-out and embedded chip technologies. To achieve the more effective thermal management and higher reliability under thermal cycling, a new optimization method called Ant colony optimization-back...

journal article 2021

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Adaptive bidirectional extracellular electron transfer during accelerated microbiologically influenced corrosion of stainless steel

Li, Z. (author), Chang, Weiwei (author), Cui, Tianyu (author), Xu, Dake (author), Zhang, Dawei (author), Lou, Yuntian (author), Qian, Hongchang (author), Song, Hao (author), Mol, J.M.C. (author), Cao, Fahe (author), Gu, Tingyue (author), Li, Xiaogang (author)

Microbiologically influenced corrosion of metals is prevalent in both natural and industrial environments, causing enormous structural damage and economic loss. Exactly how microbes influence corrosion remains controversial. Here, we show that the pitting corrosion of stainless steel is accelerated in the presence of Shewanella oneidensis MR...

journal article 2021