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Acta Metallurgica Sinica(English Letters) 2017年第11期30卷 1080-1088页

作者： Jing han Jia-peng Sun Ying han Huan Liu School of Mechanical and Electrical Engineering China University of Mining and Technology College of Mechanics and Materials Hohai University Key Laboratory of Advanced Structural Materials Ministry of EducationChangchun University of Technology

To develop a fundamental understanding of the flow behavior and optimal hot workability parameters of this material, the hot workability and deformation mechanisms of the as-cast 21Cr EDSS were studied using processing map technology combined with microstructure analysis and isothermal hot compression over the temperature range of 1000-1150 ℃ and strain rate range of 0.01-10 s-1. The processing maps and constitutive equation of peak stress were developed based on Prasad＇s and Murty＇s criteria. The results show that the processing maps exhibit a stable domain at 1000-1150 ℃ and 0.01-1 s-1. The instability domain is exhibited at high strain rates （≥1 s-l）. This implies that Murty＇s criterion can predict the unstable domain with high reliability. The detailed deformation mechanisms are also studied by microstructure observation, showing that the flow localization and microcracking are responsible for the flow instability.

关键词： Duplex stainless steel Constitutive relationship Processing map Hot deformation behavior

A combined algorithm of K-means and MTRL for multi-class classification

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Journal of Systems Engineering and Electronics 2019年第5期30卷 875-885页

作者： XUE Mengfan han Lei peng Dongliang School of Automation Hangzhou Dianzi University

The basic idea of multi-class classification is a disassembly method,which is to decompose a multi-class classification task into several binary classification *** order to improve the accuracy of multi-class classification in the case of insufficient samples,this paper proposes a multi-class classification method combining K-means and multi-task relationship learning(MTRL).The method first uses the split method of One *** to disassemble the multi-class classification task into binary classification tasks.K-means is used to down sample the dataset of each task,which can prevent over-fitting of the model while reducing training ***,the sampled dataset is applied to the MTRL,and multiple binary classifiers are trained *** the help of MTRL,this method can utilize the inter-task association to train the model,and achieve the purpose of improving the classification accuracy of each binary *** effectiveness of the proposed approach is demonstrated by experimental results on the Iris dataset,Wine dataset,Multiple Features dataset,Wireless Indoor Localization dataset and Avila dataset.

关键词： machine learning multi-class classification K-means multi-task relationship learning (MTRL) over-fitting

Dependency of gamma oscillations in E/I neuronal network on illumination contrast of external stimulus

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Theoretical & Applied Mechanics Letters 2019年第1期9卷 14-20,I0006页

作者： Xiaochun Gu Fang han Zhijie wang Xia peng College of Information Science and Technology Donghua University

Synchronous gamma oscillations are believed to play a prominent role in the information processing of biological neural systems. Experimental observations have found that the frequency and power of gamma oscillations in the primary visual cortex(V1 zone) are regulated by the illumination contrast of visual stimulus. However, the underlying mechanism of how the synchronous oscillations depend on the illumination contrast has not been well explained. We propose a local excitatory/inhibitory(E/I) neuronal network of integrate-and-fire(IAF) neurons with the difference-of-Gaussians(DOG) receptive field to unveil this mechanism. Simulation results demonstrate that the higher the illumination contrast, the higher the frequency of gamma oscillations. The power of gamma oscillations also increases with the increase of illumination contrast. These results are consistent with the experimental findings.

关键词： Gamma oscillations Illumination contrast E/I network Receptive field

Melanin/polydopamine-based nanomaterials for biomedical applications

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Science China Chemistry 2019年第2期62卷 162-188页

作者： Chao Qi Lian-Hua Fu han Xu Tian-Fu wang Jing Lin peng Huang Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging Carson International Cancer Center Laboratory of Evolutionary Theranostics School of Biomedical Engineering Health Science Center Shenzhen University Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Optoelectronic Engineering Shenzhen University

The natural melanin is one kind of ubiquitous biological pigments, which is produced in melanosomes and widely distributed in living organisms. The synthetic melanin, often known as polydopamine(PDA), has similar chemical compositions and physical properties to natural melanin. In recent years, both natural melanin and PDA have aroused increased research interests in biomedical fields owing to their inherent biocompatibility, antioxidant activity, free-radical scavenging, metal ion chelation,strong near-infrared absorption and high photothermal conversion efficiency. Inspired by these fascinating properties, melanin and PDA have been widely used as building blocks for the construction of multifunctional nanoplatforms for various biomedical applications. This review focuses on the state-of-the-art progress in melanin/PDA-based nanomaterials, which covers from their preparation methods to biomedical applications including bioimaging, treatment, theranostics, antibacterial, UV/radiation protection, biosensor and tissue engineering. Moreover, the current trends and the future prospects of melanin/PDA-based nanomaterials are also discussed.

关键词： melanin polydopamine nanomaterials biomedical applications

Investigating core axial power distribution with multiconcentration gadolinium in PWR

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Nuclear Science and Techniques 2022年第11期33卷 22-32页

作者： Jing-Gang Li Jing-han peng Chao wang Jun Chen Fei Xu Yun-Fan Ma China Nuclear Power Technology Research Institute Shenzhen 518000China

Core axial power distribution is an essential topic in pressurized water reactor(PWR)reactivity *** PWRs limit stability against axial core power oscillations at a high-cycle *** the‘‘camel’’peak power shape typically occurs with increasing depletion,the approaches used for the axial power control deserve special *** study aims to investigate the performance of different gadolinium rod design schemes in core axial power control during power operation based on the reactivity balance strategy,and to propose new multiconcentration gadolinium rod design *** the new design schemes,low-concentration gadolinium pellets are filled in the axial hump part of the gadolinium rod,and high-concentration gadolinium pellets are filled in the other *** impact of different gadolinium rod design schemes on the main core characteristics was evaluated using the nuclear design code package PCM developed by *** results show that the new gadolinium rod design significantly impacts the core axial power *** new design schemes can efficiently improve the core axial power distribution along the entire cycle by reducing the core axial power peak at the end of a cycle,enhancing the reactor operation stability,and achieving a better core safety margin,revealing a sizeable potential application.

关键词： Gadolinium PCM software package Fuel assembly Core axial power distribution Reactivity

Recovery of iron from high phosphorus oolitic iron ore using coal-based reduction followed by magnetic separation

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International Journal of Minerals,Metallurgy and Materials 2013年第5期20卷 411-419页

作者： Yong-sheng Sun Yue-xin han peng Gao Ze-hong wang Duo-zhen Ren College of Resources and Civil Engineering Northeastern University

Oolitic iron ore is one of the most important iron resources. This paper reports the recovery of iron from high phosphorus oolitic iron ore using coal-based reduction and magnetic separation. The influences of reduction temperature, reduction time, C/O mole ratio, and CaO content on the metallization degree and iron recovery were investigated in detail. Experimental results show that reduced products with the metallization degree of 95.82% could be produced under the optimal conditions （i.e., reduction temperature, 1250℃; reduction time, 50 min; C/O mole ratio, 2.0; and CaO content, 10wt%）. The magnetic concentrate containing 89.63wt% Fe with the iron recovery of 96.21% was obtained. According to the mineralogical and morphologic analysis, the iron minerals had been reduced and iron was mainly enriched into the metallic iron phase embedded in the slag matrix in the form of spherical particles. Apatite was also reduced to phosphorus, which partially migrated into the metallic iron phase.

关键词： oolitic iron ore iron ore reduction magnetic separation phosphorus

Shear-thinning behavior of the CaO–SiO2–CaF2–Si3N4 system mold flux and its practical application

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International Journal of Minerals,Metallurgy and Materials 2017年第10期24卷 1096-1103页

作者： Ying Xu Zhi-peng Yuan Li-guang Zhu Yi-hua han Xing-juan wang Hebei Provincial Key Laboratory of Inorganic Nonmetallic Materials College of Materials Science and Engineering North China University of Science and Technology Tangshan 063009 China Key Laboratory for Advanced Metallurgy Technology Hebei Provincial High-Quality Steel Continuous Casting Engineering Technology Research Center College of Metallurgy & Energy North China University of Science and Technology Tangshan 063009 China

Satisfying the mold-flux performance requirements for high-speed continuous casting necessitates the development of a new non-Newtonian-fluid mold flux with shear-thinning behavior, i.e., a mold flux whose viscosity is relatively high under lower shear rates and relatively low under higher shear rates. In this work, a mold flux that exhibits shear-thinning behavior was developed by adding different amounts of Si_3N_4 to the CaO–SiO_2–CaF_2 mold flux. The shear-thinning behavior was investigated using a rotational viscometer. In addition, the microstructure of the newly prepared slags was studied by high-temperature Raman spectroscopy and X-ray photoelectron spectroscopy. The results showed that the mechanism of shear-thinning was attributable to a temporary viscosity loss caused by the one-way shear stress, whereas the corresponding magnitude of shear-thinning was closely related to the degree of polymerization(DP). Finally, the non-Newtonian fluid mold flux was used for laboratory casting tests, which revealed that the mold flux could reduce slag entrapment and positively affect the continuous casting optimization.

关键词： mold flux viscosity shear-thinning behavior non-Newtonian fluid degree of polymerization

Realization of a full hierarchical topology in hexagonal bilayer acoustic crystals

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Science China(Physics,Mechanics & Astronomy) 2023年第10期66卷 62-69页

作者： Suhao wang han Jia Xinghang Yang peng Zhang Yunhan Yang Yuzhen Yang Xiaodong Li Key Laboratory of Noise and Vibration Research Institute of AcousticsChinese Academy of SciencesBejing 00190China University of Chinese Academy of Sciences Bejing 100049China State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBejing 100190China

Recently, there has been significant research interest in higher-order topological states within artificial lattices, primarily due to their potential for manipulating waves. In this study, we focus on a three-dimensional hexagonal bilayer acoustic crystal with rotation, layer, and translation degrees of freedom. By systematically reducing the crystal symmetries, we realize a full hierarchical structure of the higher-order topological states. This hierarchical progression begins with the valley-induced twodimensional surface state, followed by the one-dimensional hinge state that arises from the topological obstruction, and ultimately culminating in the zero-dimensional corner state resulting from the edge polarization mechanism. Through finite element simulations and numerical calculations of topological invariants, we confirm the topological origins of all these hierarchical states. Moreover, we successfully verified the full hierarchical topology by directly probing the acoustic field within a finitesized three-dimensional sample. This study offers novel perspectives on the fundamental research pertaining to wave modulation and the intelligent control of sound fields.

关键词： higher-order topological states three-dimensional acoustic crystal hierarchical topology wave modulation

Effect of seepage on soil arching effect in deep shield tunnel

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Underground Space 2023年第5期12卷 218-233页

作者： Xu Song Fan-Yan Meng Ren-peng Chen han-Lin wang Huai-Na Wu Research Center for Advanced Underground Space Technologies of Hunan University Changsha 410082China Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education Hunan UniversityChangsha 410082China College of Civil Engineering Hunan UniversityChangsha 410082China

Shield tunneling and post-tunneling steady seepage are accompanied by stress and displacement variations,which could induce and influence the soil arching *** there are many studies on the tunneling-induced soil arching effect,the research about the effect of seepage on soil arching effect is extremely *** this study,a numerical model is firstly established and verified by field ***,a series of numerical models,whose simulation method of steady seepage is verified by adopting the conformal mapping technique,are established to study the soil arching evolution of deep-buried tunneling and post-construction steady *** results indicate that seepage leads to an increase in effective vertical stress,which is consistent with the existing *** seepage weakens the soil arching effect resulting in the height of the arch zone reducing from 2.38D(D is the tunnel diameter)to *** seepage leads to the further development of ground consolidation settlement,but the differential displacement in the soil mass *** ground reaction curve in the steady seepage condition shows a bigger value than that after *** is reasonable to control the ground loss ratio in the range of 0.5–1.0%,which can minimize overburden pressure with moderate ground deformation.

关键词： Soil arching effect Steady seepage Numerical simulation Deep shield tunnel Stress change

Thermo-reversible MWCNTs/Epoxy Polymer for Use in Self-healing and Recyclable Epoxy Adhesive

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Chinese Journal of Polymer Science 2017年第6期35卷 728-738页

作者： Ya-kun Guo han Li peng-xiang Zhao Xiao-fang wang Didier Astruc 帅茂兵 Institute of Materials China Academy of Engineering Physics Department of Materials Southwest University of Science and Technology Institut des Sciences Moleculaires University Bordeaux

A self-healing and recyclable carbon tube/epoxy adhesive was prepared by epoxy monomer with Diels-Alder （DA） bonds, diethylenetriamine and polyethyleneimine modified multi-wall carbon nanotubes （MWCNTs）. The self-healing and recyclable ability was attained by thermally reversible Diels-Alder reaction between furan and maleimide in the epoxy monomer. By controlling the molar ratio of furfuryl glycidyl ether and 4,4＇-methylenebis（N-phenylmaleimide）, the glass transition temperature and mechanical properties of MWCNTs/epoxy adhesives were varied. The self-healing properties of MWCNTs/epoxy polymers were evaluated by lap shear experiment and the results showed that the MWCNTs/epoxy adhesives exhibited enhanced mechanical properties and excellent self-healing ability under heat stimulus. The healing efficiency was related to the molecule mobility and the conversion of DA reaction between furan and maleimide. The MWCNTs/epoxy adhesives also displayed excellent recyclable ability by transforming into soluble polymer under heating. These materials offer a wide range of possibilities to produce materials with healing and recyclable ability and have the potential to bring great benefits to our daily lives by enhancing the safety, performance, and lifetime of products.

关键词： Self-healing Recyclable Epoxy adhesives MWCNTs Diels-Alder reaction