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International Journal of Minerals,Metallurgy and Materials 2019年第7期26卷 869-877页

作者： Wen-bo luo zhi-yong Xue Wei-min Mao School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Institute for Advanced Materials North China Electric Power University Beijing 102206 China School of Energy Power and Mechanical Engineering North China Electric Power University Beijing 102206 China

In this paper, the microstructure evolution of the rapidly solidified (RS) Mg61.7Zn34Gd4.3 (at%, atomic ratio) alloy at high temperatures was investigated. The hardness and elastic modulus of the main precipitated phases were also analyzed and compared with those of the α-Mg matrix on the basis of nanoindentation tests. The results show that the RS alloy consists of either a petal-like icosahedral quasicrystal (IQC) phase (~20 μm) and block-shaped H1 phase (~15 μm) or IQC particles with an average grain size of ~107 nm as well as a small proportion of amorphous phase, which mainly depends on the holding time at the liquid temperature and the thickness of the ribbons. The IQC phase gradually transforms at 400?C to a short-rod-shaped μ-phase (Mg28.6Zn63.8Gd7.7) with a hexagonal structure. The hardness of the IQC phase is higher than that of H1 phase, and both phases exhibit a higher hardness than the α-Mg matrix and the μ-phase. The elasticity of the H1 phase is superior to that of the α-Mg matrix. The IQC phase possesses a higher elastic modulus than H1 phase. The easily formed H1 phase exhibits the poorest plastic deformation capacity among these phases but a higher elastic modulus than the α-Mg matrix.

关键词： magnesium alloy icosahedral phase rapidly solidification nanoindentation micromechanical properties

Reduced graphene oxide-supported CoP nanocrystals confined in porous nitrogen-doped carbon nanowire for highly enhanced lithium/sodium storage and hydrogen evolution reaction

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Nano Research 2019年第11期12卷 2872-2880页

作者： Xiaojun Zhao Dan luo Yan Wang zhi-Hong Liu Key Laboratory for Macromolecular Science of Shaanxi Province School of Chemistry and Chemical EngineeringShaanxi Normal UniversityXi’an710062China

Rational synthesis of a hierarchical porous architecture with highly active and consecutive conductive network is very critical to achieve the high-performance of nanomaterials in electrochemical energy conversion and *** propose here a hierarchical micro-/nanostructured hybrids constructed by the dual carbon shell nanowire host containing CoP nanocrystals of several nanometers,which generates Co-based metal-organic framework on graphene oxide nanosheets in situ and followed a direct phosphorization(CoP@NC/rGO).The dual carbon shell,consisting of Co-based metal-organic framework derived porous doped carbon(NC)and reduced graphene oxide(rGO),can not only impedes CoP nanocrystals from coalescing,and renders highly exposed the electrochemically accessible active sites,but also provides the multidimensional pathways for rapid electron and ion *** importantly,the covered dual carbon shell on CoP nanocrystals plays a role as a protective layer to impede the nanocrystals’*** virtue of compositional and structural advantages,the micro-/nanostructured CoP@NC/rGO hybrids manifest outstanding energy storage properties when evaluated as anodes for lithium/sodium ion ***,it also reveals highly efficient electrocatalytic performance for hydrogen evolution reaction in acid media with low Tafel slope,overpotential and robust durability.

关键词： micro-/nanostructured metal-organic framework CoP@NC/rGO lithium/sodium ion batteries hydrogen evolution reaction

Rapid chemical recycling of waste polyester plastics catalyzed by recyclable catalyst

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Green Chemical Engineering 2024年第2期5卷 257-265页

作者： Yu-Ji luo Jia-Yin Sun zhi Li School of Physical Science and Technology ShanghaiTech UniversityShanghai201210China

Waste plastics are serious environmental threats due to their low degradability and low recycling *** and efficient waste plastics recycling technologies are urgently demanded for a sustainable ***,we report a rapid,closed-loop,and streamlined process to convert polyesters such as poly(ethylene terephthalate)(PET)back to its purified *** trifluoromethanesulfonic acid or metal triflates as the recyclable catalyst,polyesters such as PET can be completely depolymerized by simple carboxylic acids within 1 *** coupling this acidolysis with a subsequent hydrogenolysis process,the consumed carboxylic acid was recovered and the closed-loop of PET depolymerization could be *** catalysts and depolymerization agents are fully recycled while only PET and hydrogen are consumed.

关键词： Chemical recycling Waste polyester plastics Acidolysis Recyclable catalyst

Coherent interaction and action–counteraction theory in small polaron systems,and ground state properties

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Chinese Physics B 2022年第11期31卷 474-481页

作者： zhi-Hua luo Chao-Fan Yu School of Physics and Information Engineering Guangdong University of EducationGuangzhou 510303China

Based on the coherent interaction and action–counteraction principles,we investigate the ground state properties for small polaron systems,the coherent-squeezed fluctuation correction,and the anomalous lattice quantum fluctuation,with the new variational generator containing correlated squeezed-coherent coupling and quantum *** tha t-2t is the ***,for the coherent interaction effect,we find the ground-state energy E_(0)to be-2.428t,in which the coherent squeezed fluctuation correction-A_(0)t is-0.463t(where t is the hopping integral,ωis the phonon frequency),with the electron–one-phonon coupling constant g=1 and the electron–two-phonon coupling constant g_(1)=-***,as a result of the action–counteraction effect,E_(0)is-2.788t,but-E_(0)t *** to the polaron binding energy(EP),for the coherent interaction effect,E_(P) is-1.38ω,but for the action–counteraction effect,E_(P) is-1.88ω.In particular,the electron–two-phonon interaction noticeably enlarges the coherent interaction and the coherent squeezed quantum fluctuation *** intervening with the quantum entanglement,the evolutions of the squeezed coherent state and the lattice quantum fluctuation begin to take *** that time,we encounter a new quantum phase coherence phenomenon—the collapse and revival of inversion repeatedly for the coherent state in the entangled evolution.

关键词： coherent interaction and action-counteraction correlated representation variational approach entangled-squeezed coherent state interaction of electron with the coherent squeezed fluctuation

Numerical simulation on characteristics of COREX shaft furnace with central gas distribution

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Journal of Iron and Steel Research International 2019年第6期26卷 567-577页

作者： Xing-sheng Zhang Zong-shu Zou zhi-guo luo Department of Ferrous Metallurgy School of Metallurgy Northeastern University Shenyang 110819 Liaoning China Key Laboratory of Ecological Utilization of Multi-metallic Mineral of Education Ministry Northeastern University Shenyang 110819 Liaoning China

A three-dimensional steady-state mathematical model, considering the chemical reactions and transfers of momentum, heat and mass between the gas and solid phases, was developed to investigate the characteristics of the shaft furnace with the central gas distribution (CGD) device. The model was verified by the practical production data of a COREX-3000 shaft furnace, and then, it was used to study the inner characteristics of the shaft furnace with CGD. The results show that, compared with the COREX shaft furnace without CGD, the gas utilization rate (UR) and solid metallization rate (MR) increase from 33.66% to 34.18% and 60.4% to 61.8%, respectively. Especially, the standard deviation of solid MR decreases from 6.9% to 0.8%, which means that the MR of direct reduced iron from the furnace with CGD is more uniform than that without CGD. Additionally, the effects of operational conditions and CGD design on gas UR, solid MR and direct reduced iron uniformity were further discussed and the optimized conditions were suggested.

关键词： COREX shaft furnace Central gas distribution Gas utilization Solid metallization Direct reduced iron uniformity

First-order primal-dual algorithm for sparse-view neutron computed tomography-based three-dimensional image reconstruction

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Nuclear Science and Techniques 2023年第8期34卷 35-53页

作者： Yang Liu Teng-Fei Zhu zhi luo Xiao-Ping Ouyang School of Nuclear Science and Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Xi’an 710024China

Neutron computed tomography(NCT)is widely used as a noninvasive measurement technique in nuclear engineering,thermal hydraulics,and cultural *** neutron source intensity of NCT is usually low and the scan time is long,resulting in a projection image containing severe *** reduce the scanning time and increase the image reconstruction quality,an effective reconstruction algorithm must be *** CT image reconstruction,the reconstruction algorithms can be divided into three categories:analytical algorithms,iterative algorithms,and deep *** the analytical algorithm requires complete projection data,it is not suitable for reconstruction in harsh environments,such as strong radia-tion,high temperature,and high *** learning requires large amounts of data and complex models,which cannot be easily deployed,as well as has a high computational complexity and poor ***,this paper proposes the OS-SART-PDTV iterative algorithm,which uses the ordered subset simultaneous algebraic reconstruction technique(OS-SART)algorithm to reconstruct the image and the first-order primal–dual algorithm to solve the total variation(PDTV),for sparse-view NCT three-dimensional *** novel algorithm was compared with other algorithms(FBP,OS-SART-TV,OS-SART-AwTV,and OS-SART-FGPTV)by simulating the experimental data and actual neutron projection *** reconstruction results demonstrate that the proposed algorithm outperforms the FBP,OS-SART-TV,OS-SART-AwTV,and OS-SART-FGPTV algorithms in terms of preserving edge structure,denoising,and suppressing artifacts.

关键词： NCT First-order primal-dual algorithm OS-SART Total variation Sparse-view

Sparse-view neutron CT 3D image reconstruction algorithm based on split Bregman method

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Nuclear Science and Techniques 2024年第9期35卷 41-55页

作者： Teng-Fei Zhu Yang Liu zhi luo Xiao-Ping Ouyang School of Nuclear Science and Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Xi’an 710024China

As a complement to X-ray computed tomography(CT),neutron tomography has been extensively used in nuclear engineer-ing,materials science,cultural heritage,and industrial *** of the attenuation matrix for neutron tomography with a traditional analytical algorithm requires hundreds of projection views in the range of 0°to 180°and typically takes several hours to *** a low time-resolved resolution degrades the quality of neutron *** the number of projection acquisitions is an important approach to improve the time resolution of images;however,this requires efficient reconstruction ***,sparse-view reconstruction algorithms in neutron tomography need to be *** this study,we investigated the three-dimensional reconstruction algorithm for sparse-view neu-tron CT *** enhance the reconstructed image quality of neutron CT,we propose an algorithm that uses OS-SART to reconstruct images and a split Bregman to solve for the total variation(SBTV).A comparative analysis of the performances of each reconstruction algorithm was performed using simulated and actual experimental *** to the analyzed results,OS-SART-SBTV is superior to the other algorithms in terms of denoising,suppressing artifacts,and preserving detailed structural information of images.

关键词： Neutron CT OS-SART Sparse-view 3D reconstruction Split Bregman Total variation

Progress of hidden spin polarization in inversion-symmetric crystals

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Science China(Physics,Mechanics & Astronomy) 2022年第3期65卷 1-18页

作者： Shan Guan Jia-Xin Xiong zhi Wang Jun-Wei luo State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Beijing Academy of Quantum Information Sciences Beijing 100193China

Hidden spin polarization refers to that doubly degenerate bands protected by combined inversion and time-reversal symmetry in nonmagnetic inversion-symmetric crystals could have opposite non-zero local spin polarizations, which are spatially separated in two real-space sectors paired by the inversion symmetry. Since its first prediction from ab initio calculation, hidden spin polarization has inspired tremendous interest and has been observed experimentally due to its intriguing fundamental properties as well as the great potential for applications. Moving forward, the search for moment-dependent spin splitting has also been extended to antiferromagnets even without considering spin-orbit coupling. This paper systematically reviews recent works in this field with a focus on basic concepts and material realization. It also details several remaining bottlenecks and suggests possible avenues for future research.

关键词： spin-orbit coupling hidden spin polarization tight-binding model ab initio calculation

3D robust anisotropic diffusion filtering algorithm for sparse view neutron computed tomography 3D image reconstruction

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Nuclear Science and Techniques 2024年第3期35卷 13-29页

The most critical part of a neutron computed tomography(NCT) system is the image processing algorithm,which directly affects the quality and speed of the reconstructed *** types of noise in the system can degrade the quality of the reconstructed ***,to improve the quality of the reconstructed images of NCT systems,efficient image processing algorithms must be *** anisotropic diffusion filtering(ADF) algorithm can not only effectively suppress the noise in the projection data,but also preserve the image edge structure information by reducing the diffusion at the image ***,we propose the application of the ADF algorithm for NCT image *** compare the performance of different algorithms in NCT systems,we reconstructed images using the ordered subset simultaneous algebraic reconstruction technique(OS-SART) algorithm with different regular terms as image processing *** the iterative reconstruction,we selected two image processing algorithms,the Total Variation and split Bregman solved total variation algorithms,for comparison with the performance of the ADF ***,the filtered back-projection algorithm was used for comparison with an iterative *** reconstructing the projection data of the numerical and clock models,we compared and analyzed the effects of each algorithm applied in the NCT *** on the reconstruction results,OS-SART-ADF outperformed the other algorithms in terms of denoising,preserving the edge structure,and suppressing *** example,when the 3D Shepp–Logan was reconstructed at 25 views,the root mean square error of OS-SART-ADF was the smallest among the four iterative algorithms,at only *** universal quality index,mean structural similarity,and correlation coefficient of the reconstructed image were the largest among all algorithms,with values of 0.9877,0.9878,and 0.9887,respectively.

关键词： NCT OS-SART Sparse-view Anisotropic diffusion filtering

High-Order Two-Scale Asymptotic Paradigm for the Elastodynamic Homogenization of Periodic Composites

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Acta Mechanica Solida Sinica 2024年第1期37卷 124-138页

作者： Wei-zhi luo Mu He Liang Xia Qi-Chang He State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Laboratoire Modélisation et Simulation Multi-Echelle MSME UMR 8208 CNRSUniversite Gustave Eiffel77454 Marne-la-ValléeFrance

The classical two-scale asymptotic paradigm provides macroscopic and microscopic analyses for the elastodynamic homogenization of periodic composites based on the spatial or/and temporal variable,which offers an approximate framework for the asymptotic homogenization analysis of the motion ***,in this framework,the growing complexity of the homogenization formulation gradually becomes an obstacle as the asymptotic order *** such a context,a compact,fast,and accurate asymptotic paradigm is *** work reviews the high-order spatial two-scale asymptotic paradigm with the effective displacement field representation and optimizes the implementation by symmetrizing the tensor to be ***,the modified implementation gets rid of the excessive memory consumption required for computing the high-order tensor,which is demonstrated by representative one-and two-dimensional *** numerical results show that(1)the contrast of the material parameters between media in composites directly affects the convergence rate of the asymptotic results for the homogenization of periodic composites,(2)the convergence error of the asymptotic results mainly comes from the truncation error of the modified asymptotic homogenized motion equation,and(3)the excessive norm of the normalized wavenumber vector in the two-dimensional inclusion case may lead to a non-convergence of the asymptotic results.

关键词： Composites Homogenization Asymptotic analysis Dynamics Dispersion