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International Journal of Smart and Nano Materials 2011年第4期2卷 283-291页

作者： hui Xia chao huo School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjingJiangsu 210094P.R.China National Institute of Metrology China Bei San Huan Dong Road 18Beijing 100013P.R.China

A MnO_(2)/carbon nanotube(CNT)nanocomposite was synthesised using a simple hydrothermal *** nanocomposite exhibits a CNT core/MnO_(2)porous sheath hierarchy architecture,which makes it promising as an electrode material for *** asymmetric supercapacitor based on activated carbon(AC)as anode,MnO_(2)/CNT nanocomposite as cathode and 1M Na_(2)SO_(4)solution as electrolyte was assembled in a Swagelok *** full cell exhibits excellent power capability,cycling stability and a high energy density of 23 W h/kg at a power density of 330 W/kg based on the total mass of the active electrode *** AC//MnO_(2)/CNT asymmetric supercapacitor is promising for high-power applications due to its high energy density and power density.

关键词： supercapacitor carbon nanotube nanocomposite

Dual-reaction-center catalytic process continues Fenton's story

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Frontiers of Environmental Science & Engineering 2020年第5期14卷 65-73页

作者： chao Lu Kanglan Deng Chun hu Lai Lyu Institute of Environmental Research at Greater Bay Area Key Laboratory for Water Quality and Conservation of the Pearl River Delta(Ministry of Education)Guangzhou UniversityGuangzhou 510006China

Triggered by global water quality safety issues,the research on wastewater treatment and water purification technology has been greatly developed in recent *** Fenton technology is particularly powerful due to the rapid attack on pollutants by the generated hydroxyl radicals(·Oh).however,both heterogeneous and homogeneous Fenton/Fenton-like technologies follow the classical reaction mechanism,which depends on the oxidation and reduction of the transition metal ions at single *** even after a century of development,this reaction still suffers from its inherent bottlenecks in practical *** recent years,our group has been focusing on studying a novel heterogeneous Fenton catalytic process,and we developed the dual-reaction-center(DRC)system for the first *** the DRC system,h2O2 and O2 can be efficiently reduced to reactive oxygen species(ROS)in electron-rich centers,while pollutants are captured and oxidized by the electron-deficient *** obtained electrons from pollutants are diverted to the electron-rich centers through bonding *** process breaks through the classic Fenton mechanism,and improves the performance and efficiency of pollutant removal in a wide ph ***,we provide a brief overview of Fenton's story and focus on combing the discovery and development of the DRC technology and mechanism in recent *** construction of the DRC and its performance in the pollutant degradation and interfacial reaction process are described in *** look forward to bringing a new perspective to continue Fenton's story through research and development of DRC technology.

关键词： Dual reaction centers Fenton Pollutant utilization Electron transfer

Numerical Investigations on the Impact of Turbulent Prandtl Number and Schmidt Number on Supersonic Combustion

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Fluid Dynamics & Materials Processing 2020年第3期16卷 637-650页

作者： Yongkang Zheng chao Yan National Key Laboratory of Computational Fluid Dynamics Beihang UniversityBeijing100191China State Key Laboratory of Aerodynamics Mianyang621000China

The flow field inside the combustor of a scramjet is highly complicated and the related turbulent Prandtl and Schmidt numbers have a significant impact on the effective numerical prediction of such *** in many cases researchers set these parameters on the basis of purely empirical laws,assessing their impact(via parametric numerical simulations)is a subject of great *** the present work,in particular,two test cases with different characteristics are selected for further evaluation of the role played by these non-dimensional numbers:Burrows-Kurkov case and DLR *** numerical results indicate that these parameters influence ignition ***,the temperature distribution is more sensitive to them than to h2O mass fraction and velocity distributions.

关键词： Turbulent Prandtl number turbulent Schmidt number ignition position supersonic combustion

Surface-tuning nanoporous AuCu_(3) engineering syngas proportion by electrochemical conversion of CO_(2)

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Nano Research 2021年第11期14卷 3907-3912页

作者： chao An Yongli Shen Wenxiu Yan Linxiu Dai Changhua An Life and health Institute Tianjin Key Laboratory of Organic Solar Cells and Photochemical ConversionSchool of Chemistry and Chemical EngineeringTianjin University of TechnologyTianjin300384China Department of Materials Science and Engineering College of EngineeringPeking UniversityBeijing100871China

The direct electrochemical conversion of CO_(2) to syngas with controllable composition remains challenging. In this work, driven by concentration gradient, a simple air-heating aided strategy has been developed to adjust surface composition of the self-supporting nanoporous AuCu_(3) alloy. According to Fick First Law, the interior Cu atoms of the AuCu_(3) alloy with Au-rich surface gradually segregated outwards during heating, realizing Cu-rich surface eventually. Correspondingly, the competing electrocatalytic CO_(2) reduction (ECR) to CO and hydrogen evolution reactions (hER) were tactfully balanced on these alloy surfaces, thus achieving proportion-tunable syngas (CO/h2). Density functional theory (DFT) calculations on the Gibbs free energy change of the COOh* and h* (ΔGCOOh*, ΔGh*) on the alloy surfaces were conducted, which are generally considered as the selectivity descriptors for CO and h2 products, respectively. It shows ΔGCOOh* gradually increases in contrast to the decreased ΔGh* with more Cu on the surface, suggesting h2 is more favored over Cu sites, which is consistent with the declining CO/h2 ratio observed in the experiments. This study reveals that the surface composition controls ECR activity of nanoporous AuCu_(3) alloy, providing an alternative way to the syngas production with desirable proportion.

关键词： AuCu3 surface segregation CO2 reduction syngas

EQ_1^(rot) nonconforming finite element approximation to Signorini problem

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Science China Mathematics 2013年第6期56卷 1301-1311页

作者： ShI DongYang XU chao Department of Mathematics Zhengzhou University Department of Mathematics and Physics Luoyang Institute of Science and Technology

Abstract In this paper, we apply EQ1^rot nonconforming finite element to approximate Signorini problem. If 5 the exact solution u EQ1^rot, the error estimate of order O（h） about the broken energy norm is obtained for quadrilateral meshes satisfying regularity assumption and bi-section condition. Furthermore, the superconver- gence results of order EQ1^rot are derived for rectangular meshes. Numerical results are presented to confirm the considered theory.

关键词： Signorini problem nonconforming finite element superconvergence error estimate

Interface structure of α-Mg/14h-LPSO:First-principles prediction and experimental study

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Journal of Rare Earths 2024年第9期42卷 1792-1799,I0006页

作者： Yuan Shi Xiaohua Zhang hongyan Yue chao Li School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin150040China

The interfacial structure of the α-Mg/14h-LPSO phase in rare earth-including magnesium alloy was investigated via high-angle annular dark-field scanning transmission electron microscopy(hAADFSTEM) imaging and first-principles calculations of density-functional *** possible interfacial models were constructed according to the different terminations of the LPSO phase,and the corresponding interfacial energies were calculated,from which the four most stable structures(Terl-MgY-hollow,Ter2-Zn-hollow,Ter3-MgYII-hollow and Ter4-Mg-bridge) were *** interfacial phase diagrams related to the Y chemical potentials were obtained from the calculations,and the most stable interfacial structure was ***-MgY-hollow and Ter2-Zn-hollow have the lowest interfacial energies in the range of-0.7 eV here fluctuating change of state is the minimized and the interface is the most *** separation work of the two models was calculated to predict the bonding strength of the structures at both ends of the *** calculation results show that the maximum interfacial separation work is 1.45 J/m^(2) for the interface model of α-Mg and 14h-LPSO phase structure with Ter2-Zn-hollow termination.

关键词： Rare earths Magnesium alloy hAADF-STEM LPSO First-principles Interface

Investigation of the structural, electronic and mechanical properties of CaO–SiO_(2) compound particles in steel based on density functional theory

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International Journal of Minerals,Metallurgy and Materials 2023年第4期30卷 744-755页

作者： chao Gu Ziyu Lyu Qin hu Yanping Bao State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China

CaO–SiO_(2)compounds compromise one of the most common series of oxide particles in liquid steels, which could significantly affect the service performance of the steels as crack initiation sites. however, the structural, electronic, and mechanical properties of the compounds in CaO–SiO_(2)system are still not fully clarified due to the difficulties in the experiments. In this study, a thorough investigation of these properties of CaO–SiO_(2)compound particles in steels was conducted based on first-principles density functional theory. Corresponding phases were determined by thermodynamic calculation, including gamma dicalcium silicate(γ-C2S), alpha-prime(L) dicalcium silicate(αL′-C2S), alpha-prime(h) dicalcium silicate(αh′-C2S), alpha dicalcium silicate(α-C2S), rankinite(C3S2), hatrurite(C3S), wollastonite(CS), and pseudowollastonite(Ps-CS). The results showed that the calculated crystal structures of the eight phases agree well with the experimental results. All the eight phases are stable according to the calculated formation energies, and γ-C2S is the most stable. O atom contributes the most to the reactivity of these phases. The Young’s modulus of the eight phases is in the range of 100.63–132.04 GPa. Poisson’s ratio is in the range of0.249–0.281. This study provided further understanding concerning the CaO–SiO_(2)compound particles in steels and fulfilled the corresponding property database, paving the way for inclusion engineering and design in terms of fracture-resistant steels.

关键词： CaO–SiO_(2) density functional theory structural property electronic property mechanical property

Boron leaching:Creating vacancy-rich Ni for enhanced hydrogen evolution

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Nano Research 2022年第3期15卷 1868-1873页

作者： chao han Weijie Li Jiazhao Wang Zhenguo huang School of Civil and Environmental Engineering Faculty of Engineering and Information TechnologyUniversity of Technology SydneyNSW 2007Australia Institute for Superconducting&Electronic Materials AIIM BuildingInnovation CampusUniversity of WollongongSquires WayNorth WollongongNSW 2500Australia Centre for Green Technology Faculty of Engineering and Information TechnologyUniversity of Technology SydneyNSW 2007Australia

Creating vacancy is often highly effective in enhancing the hydrogen evolution performance of transition metal-based ***-rich Ni nanosheets have been fabricated via topochemical formation of two-dimentional(2D)Ni_(2)B on graphene precursor followed by boron *** on graphene,a few atomic layered Ni_(2)B nanosheets are first obtained by reduction and *** number of atomic vacancies are then generated in the Ni_(2)B layer via leaching boron *** used for hydrogen evolution reaction(hER),the vacancy-rich Ni/Ni(Oh)_(2 )heterostructure nanosheets demonstrate remarkable performance with a low overpotential of 159 mV at a current density of 10 mA·cm^(−2) in alkaline solution,a dramatic improvement over 262 mV of its *** enhancement is associated with the formation of vacancies which introduce more active sites for hER along Ni/Ni(Oh)_(2) *** work offers a facile and universal route to introduce vacancies and improve catalytic activity.

关键词： two-dimensional structure Ni_(2)B boron leaching vacancies hydrogen evolution reaction(hER)

Effect of heat treatments on Charpy impact properties of 15Cr12MoVWN ferritic/martensitic steel

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Journal of Iron and Steel Research International 2022年第3期29卷 512-518页

作者： Ting-wei Ma Xian-chao hao Ping Wang Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang110819LiaoningChina Yingkou Institute of Technology Yingkou115014LiaoningChina CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016LiaoningChina

The Charpy impact properties of 15Cr12MoVWN ferritic/martensitic steel for sodium-cooled reactors with variation in heat treatment factors and parameters are *** results show that the ductile-to-brittle transition temperature(DBTT)increased and the upper shelf energy(USE)decreased with increase in normalizing ***,the variation tendency of DBTT and USE was the opposite with increase in tempering *** tempering temperature showed a greater influence on USE than the normalizing temperature,and normalizing and tempering temperatures had the equally significant effects on DBTT,but the cooling method was not a significant factor for DBTT and *** prior austenite grain and M_(23)C_(6) size were the main influences on DBTT,and the dislocation density was the main factor affecting the variation of *** heat-treatment regime recommended for 15Cr12MoVWN steel was composed of normalizing at 1000-1050℃ for 0.5 h followed by water quenching or air cooling and tempering at 760℃ for 1.5 h.

关键词： 15Cr12MoVWN steel Ductile-to-brittle transition temperature Prior austenite grain size M23C6-MX

Investigations of entrainment characteristics and shear-layer vortices evolution in an axisymmetric rear variable area bypass injector

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Chinese Journal of Aeronautics 2022年第4期35卷 230-244页

作者： Guoping hUANG chao LI Chen XIA Qian LI College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In this study,firstly,for the axisymmetric RVABI,the change-rule of adverse pressure gradient caused by radial velocity during the transition of internal flow mode in variable geometry is summarized,and a Bypass Ratio(BR) iterative algorithm based on the empirical correlation of non-equilibrium pressure is *** algorithm can estimate the nonlinear relationship between area ratio and BR,with an error range falling below 6.5%.Then,we discuss the favorable effect of uniform mixing on the thrust augmentation of mixed exhaust under variable BR *** this point of view,the characteristics of vortices evolution in different shear strength jets are compared,to clarify the effect of variable cycle parameters on jet *** the results suggest,when ■ is as low as 0.22,the K-h disturbance is of high-frequency wavelet property,and it is difficult to induce large-scale spanwise *** macro migrations of fluid elements in span wise vortices and the diffusion effect caused by edge tearing is weak,which is not conducive to the energy exchange between the two ***,the low ■ jet will also correspondingly weaken the viscous dissipation effect of *** is concluded that the dissipation level is proportional to the 2.31 power of the ■.

关键词： Variable cycle engine Rear variable area bypass injector Bypass ratio adjustment Mixed exhaust Thermal mixing Spanwise vortex