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浅陷阱态调控增强绿色发光钙钛矿微球的负热猝灭效应（英文）

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Science China Materials 2025年第1期 149-155页

作者：林圳旭黄锐宋捷张毅林泽文李洪亮吴海霞侯得健郭艳青王静朱剑豪 School of Materials Science and Engineering Hanshan Normal University Ministry of Education Key Laboratory of Bioinorganic and Synthetic Chemistry State Key Laboratory of Optoelectronic Materials and Technologies Sun YatSen University Department of Physics Department of Materials Science and Engineering and Department of Biomedical Engineering City University of Hong Kong

发光材料中的负热猝灭（NTQ）现象,表现为随温度升高发光强度增加,在照明和显示技术中具有广泛应用前景.然而,在金属卤化物钙钛矿中实现NTQ具有一定挑战性,其机制尚不完全清楚.本研究通过低温光致发光、长余辉和热释光谱技术,系统研究了...

发光材料中的负热猝灭（NTQ）现象,表现为随温度升高发光强度增加,在照明和显示技术中具有广泛应用前景.然而,在金属卤化物钙钛矿中实现NTQ具有一定挑战性,其机制尚不完全清楚.本研究通过低温光致发光、长余辉和热释光谱技术,系统研究了CsPbBr3微球中NTQ现象的起源.结果表明, NTQ现象与浅陷阱态中载流子的释放密切相关.实验与理论分析揭示,这些浅缺陷态的能级位于导带下方约0.135 eV处.快速热处理可显著增加浅陷阱的密度,从而增强NTQ效应,使室温下的光致发光强度较150 K时提高了60%以上.同时,该处理将受激自发辐射的阈值降低至约45 W/cm2.本研究不仅加深了对CsPbBr3微球中NTQ机制的理解,也为通过能态调控提升钙钛矿光电子器件性能开辟了新途径.

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Heterophase junction engineering-induced Co spin-state modulation of CoSe_(2) for large-current hydrogen evolution reaction

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Rare Metals 2024年第6期43卷 2660-2670页

作者： Bao-Chai Xu Ya-Ping Miao Min-Qin Mao Dong-Lian Li Song Xie Wei-hong Jin Shu Xiao Jing Wen Zaenab Abd-Allah Zhi-Tian Liu Xiang Peng Paul K.Chu Hubei Key Laboratory of Plasma Chemistry and Advanced Materials School of Materials Science and EngineeringWuhan Institute of TechnologyWuhan 430205China School of Textile Science and Engineering Xi'an Polytechnic UniversityXi'an 710048China Institute of Advanced Wear and Corrosion Resistant and Functional Materials Jinan UniversityGuangzhou 510632China Institute of Safety Science and Engineering South China University of TechnologyGuangzhou 510641China Department of Engineering Manchester Metropolitan UniversityManchester M156BHUK Department of Physics Department of Materials Science and Engineeringand Department of Biomedical EngineeringCity University of Hong KongHong Kong 999077China

Efficient electrocatalysts are vital to large-current hydrogen production in commercial water splitting for green energy ***,a novel heterophase engineering strategy is described to produce polymorphic CoSe_(2)*** composition of the electrocatalysts consisting of both cubic CoSe_(2)(c-CoSe_(2))and orthorhombic CoSe_(2)(o-CoSe_(2))phases can be controlled *** results demonstrate that junction-induced spin-state modulation of Co atoms enhances the adsorption of intermediates and accelerates charge transfer resulting in superior large-current hydrogen evolution reaction(HER)***,the CoSe_(2)based heterophase catalyst with the optimal c-CoSe_(2)content requires an overpotential of merely 240 mV to achieve 1,000 mA·cm^(-2)as well as a Tafel slope of 50.4 mV·dec^(-1).Furthermore,the electrocatalyst can maintain a large current density of 1,500 mA·cm^(-2)for over 320 h without *** results reveal the advantages and potential of heterophase junction engineering pertaining to design and fabrication of low-cost transition metal catalysts for large-current water splitting.

关键词： Heterophase junction Spin-state Hydrogen evolution reaction Large current electrochemical hydrogen production Water splitting

Microstructure and corrosion behavior of Mg-Sn-Ca alloys after extrusion

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中国有色金属学会会刊：英文版 2009年第1期19卷 40-44页

作者： T. ABU LEIL N. HORT W. DIETZEL C. BLAW ERT Y. HUANG K. U. KAINER K. P. RAO GKSS Forschungszentrum Geesthacht GmbH Max-Planck Strasse 1 Geesthacht 21502 Germany city university of hong kong 83 Tat Chee Avenue Kowloon Hong Kong

Mg-Sn-Ca alloys promise a reasonable corrosion resistance in combination with good creep resistance, likely due to the presence of Ca2-xMgxSn and other phases. The selected alloys with 3% Sn and Ca in the range of 1%-2% have been extruded in order to achieve more homogeneous microstructure compared with the as-cast alloys. Optical microscopy(OM) and X-ray diffraction(XRD) techniques were used to study the microstructure and phases of these alloys. The corrosion behavior of these alloys was investigated by means of salt spray test and potentio-dynamic measurements. The results obtained on the alloys Mg-3Sn (T3), Mg-3Sn-1Ca (TX31), and Mg-3Sn-2Ca (TX32) indicate the presence of the same phases in as-cast and after extrusion, namely Mg2Sn, Ca2-xMgxSn, and Ca2-xMgxSn/Mg2Ca, respectively. However, due to the occurrence of extensive recrystallization in the extrusion process, the grain size has significantly reduced after extrusion. The reduction leads to the improvement of the corrosion resistance after extrusion which is then comparable with the commercial alloy AZ91D.

关键词： Mg-Sn-Ca合金腐蚀镁合金金属腐蚀

Copula-Based Risk Management Models for Multivariable RMB Exchange Rate in the Process of RMB Internationalization

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Journal of Systems Science & Complexity 2017年第3期30卷 660-679页

作者： DU Jiangze LAI Kin Keung School of Finance Jiangxi University of Finance and Economics Department of Industrial and Manufacturing Systems Engineering Hong Kong University International Business School Shaanxi Normal University

This paper investigates the dependence of the exchange rate of onshore Renminbi(RMB)and offshore RMB against US dollar(i.e., CNY and CNH) based on copula models. Eleven different copulas were selected to construct multivariate distribution and estimate the value-at-risk for RMB exchange rate. Empirical results show that time-invariant Student-t copula is the best model to fit the sample data. The positive upper and lower dependence indicates that CNY and CNH series tend to move in the same direction. Moreover, the dependence between the two exchange rates is asymmetric,which means that traditional models, such as Pearson's correlation, are inappropriate to measure the correlations between these markets. The best fitted model is chosen to estimate the financial risk,which can help business practitioners and policymakers track risk evolution and make good decisions.

关键词： Copula modeling RMB exchange rate RMB internationalization value-at-risk.

Strategies for improving ductility of ordered intermetallics

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Progress in Natural Science:Materials International 2016年第1期26卷 1-12页

作者： Z.B.Jiao J.H.Luan C.T.Liu Center for Advanced Structural Materials Department of Mechanical and Biomedical Engineering College of Science and Engineering City University of Hong Kong

Ordered intermetallics possess attractive high-temperature properties; however, low ductility and brittle fracture limit their use as engineering materials in many cases. This paper provides a comprehensive review on the recent progress in the development of ductile ordered intermetallics and summarizes the strategies used to improve the tensile ductility of ordered intermetallics, including control of ordered crystal structures,engineering grain-boundary structure and chemistry, eliminating environmental embrittlement, microstructure optimization, control of phase stability, and promoting transformation-/twining-induced plasticity. The basic ideas and related mechanisms underlying these ductilizing strategies are discussed. In addition, a brief mention of the current use of intermetallic alloys for structural and corrosion applications is made.

关键词： Ordered intermetallics Ductility Ductilizing strategy Microstructure Alloy design

Aggregate Engineering in Supramolecular Polymers via Extensive Non-covalent Networks

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Chinese Journal of Polymer Science 2021年第10期39卷 1310-1318,I0007页

作者： Xin Huang Dong Lv Li-Qing Ai Shuk Han Cheng Xi Yao Department of Biomedical Sciences City University of Hong KongHong Kong 999077China city university of hong kong Shenzhen Research InstituteShenzhen 518075China

Aggregate engineering of non-covalent networks endows supramolecular polymers with thermo-mechanical versatility,stimuli-responsive phase transitions and intrinsic damage-healing ***,most non-covalent networks are vulnerable at elevated temperatures,which suppresses the robustness of supramolecular ***,ureidocytosine(UCy)motifs,which are capable of forming extensive non-covalent networks and thus robust molecular aggregates via multivalent hydrogen bonds and aromatic stackings,are proposed to enable precise programming of the thermo-mechanical *** simulations reveal that the enthalpic contributions from the UCy aggregates play dominant roles to compensate the entropic loss from the redistributions of polymeric spacers and stabilize the non-covalent networks over wide temperature *** aggregate-level strategy offers prospects for applications which require thermo-mechanical versatility of supramolecular polymers,such as 3D printing,microfabrication and damage-healing coating.

关键词： Aggregate engineering Damage-healing Extensive non-covalent network Ureidocytosine Supramolecular polymers

MODELING PHOTONIC CRYSTALS WITH COMPLEX UNIT CELLS BY DIRICHLET-TO-NEUMANN MAPS

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Journal of Computational Mathematics 2007年第3期25卷 337-349页

作者： Yuexia Huang Ya Yan Lu Department of Mathematics City University of Hong KongKowloonHong KongChina

For a photonic crystal （PhC） of finite size, it is important to calculate its transmission and reflection spectra. For two-dimensional （2-D） PhCs composed of a square lattice of circular cylinders, the problem can be solved by an efficient method based on the Dirichlet-to-Neumann （DtN） map of the unit cell and a marching scheme using a pair of operators. In this paper, the DtN operator marching method is extended to handle 2-D PhCs with complex unit cells and arbitrary lattice structures.

关键词： Photonic crystal Periodic structure Diffractive grating Dirichlet-to-Neumannmap Operator marching.

Spatially strain-induced and selective preparation of Mo_(x)N(x=1,2)as a highly effective nanoarchitectonic catalyst for hydrogen evolution reaction in a wide pH range

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Rare Metals 2023年第5期42卷 1446-1452页

作者： Chao Huang Xiao-Lin Zhang Jing Tang Dan Li Qing-Dong Ruan Liang-Liang Liu Fang-Yu Xiong Bin Wang Yue Xu Sui-Han Cui Yang Luo Qing-Wei Li Paul K.Chu Department of Physics Department of Materials Science and EngineeringCity University of Hong KongHong Kong999077China Department of Biomedical Engineering City University of Hong KongHong Kong999077China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410011China School of Mechanical Engineering Liaoning Petrochemical UniversityFushun113001China Advanced research Institute for Multidisciplinary Science Qilu University of Technology(Shandong Academy of Sciences)Jinan250307China

Developing highly efficient catalysts for the hydrogen evolution reaction(HER)is crucial to commercial water splitting in the global efforts to mitigate fossil fuel combustion and combat global climate *** nitrides(Mo... 详细信息

关键词： catalyst splitting preparation

Mechanical Behaviors of Ti-Si-N Coatings Deposited by Bias Sputtering

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稀有金属材料与工程 2012年第S1期41卷 18-23页

作者： P W Shum Advanced Coatings Applied research Laboratory(ACARL) Department of Mechanical and Biomedical Engineering(MBE)City University of Hong KongHong KongChina

Ti-Si-N hard coatings were deposited on steel substrates by reactive unbalanced magnetron sputtering from Ti and Si elemental targets in a mixture of Ar and N2 *** influences of negative bias voltage(in the range of-30 to-80 V)on the mechanical properties of the coatings were *** particular,the critical cycle during dynamic impact tests was employed to indicate the bonding strength of the *** was found that the Ti-Si-N coatings prepared at lower constant bias voltages could effectively improve the adhesion and the cyclic impact performance,but their hardness was dropped significantly to 13 GPa at a bias of-30 *** bias voltage values induced greater hardness.A maximum hardness of 47 GPa was obtained at a bias of-60 ***,the coating adhesion was worse in this case,and the number of impact cycles(～8×10 3)that the coatings could endure was much shorter than that of TiN binary coatings(～2×104).On the other hand,the bias voltage was varied linearly from-40 to-60 V during Ti-Si-N *** this circumstance,the hardness of the coatings deposited with the bias-graded configuration remained very high(42 GPa),and the adhesion strength was improved ***,the critical impact cycle could reach as high as 1.8×***,bias-graded deposition can provide an effective processing route to prepare Ti-Si-N superhard coatings with high adhesion strength and impact resistance.

关键词： Ti-Si-N coatings magnetron sputtering bias voltage mechanical properties impact test