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Rare Metals 2023年第6期42卷 2057-2067页

作者： Sen Lin yun-lai deng Hua-Qiang Lin Ling-Ying Ye Zhen Zhang Hua Ji Xin-Ming Zhang School of Materials Science and Engineering Central South UniversityChangsha410083China Light Alloy Research Institute Central South UniversityChangsha410083China Guangxi Liuzhou Yinhai Aluminum Co. LtdLiuzhou545006China National Engineering Research Center for High-Speed EMU CRRC Qingdao Sifang Co.LtdQingdao266000China

Microstructure,mechanical properties and stress corrosion behavior of friction stir welded(FSWed) AlMg-Si alloy were *** average grain sizes of shoulder-affected zone(SAZ),nugget zone(NZ),heat-affected zone(HAZ) and base material(BM) are 6.03,4.80,168.30 and 127.24 μm,*** thermo-mechanically affected zone(TMAZ),which is generated on the edge position between HAZ and weld nugget zone,has a narrow width of 400 μ*** ultimate tensile strength(UTS) of FSWed joint is 232.20 MPa,about 91.04% with respect to that of base material of 255.06 MPa,and the joint fracture occurs at HAZ on advancing side(AS).The FSWed joint is more susceptive to stress corrosion cracking(SCC) than base material,and the SCC susceptibility increases with the rise in *** residual UTS of FSWed joints in constant loaded tests at the load levels of90,105 and 120 MPa is 89.97%,67.50% and 54.75% of the UST of FSWed joint in air,*** increase of the load in constant loaded tests and four-point beambent tests accelerates the SCC of FSWed joints.

关键词： EBSD Slow strain rate test Stress corrosion cracking Al-Mg-Si alloy Friction stir welding

Calculation and experimental study on heating temperature field of super-high strength aluminum alloy thick plate

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Transactions of Nonferrous Metals Society of China 2017年第11期27卷 2415-2422页

作者： Shi-tong FAN yun-lai deng Jin ZHANG Xiao-bin GUO School of Materials Science and Engineering Central South University Changsha 410083 China State Key Laboratory of High Performance and Complex Manufacturing Central South University Changsha 410083 China Light Alloy Research Institute Central South University Changsha 410083 China

Stepped heating treatment has been applied to aluminum alloy thick plate to improve the mechanical performance and corrosion *** temperature control of the plate is the difficulty in engineering *** heating process,the calculation of surface heat transfer coefficient and the accurate temperature control method were studied based on measured heating temperature for the large-size thick *** results show that,the temperature difference between the surface and center of the thick plate is *** on the temperature uniformity,the surface heat transfer coefficient was calculated,and it is constant below300°C,but grows greatly over300°***,a lumped parameter method(LPM)was developed to predict the plate temperature.A stepped solution treatment was designed by using LPM,and verified by finite element method(FEM)and *** curves calculated by LPM and FEM agree well with the experimental data,and the LPM is more convenient in engineering application.

关键词： lumped parameter method surface heat transfer coefficient temperature field aluminum alloy thick plate

Deformation characteristics and strain-compensated constitutive equation for AA5083 aluminum alloy under hot compression

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Transactions of Nonferrous Metals Society of China 2019年第11期29卷 2252-2261页

作者： Qing-song DAI yun-lai deng Jian-guo TANG Yu WANG School of Materials Science and Engineering Central South UniversityChangsha 410083China Guangxi Liuzhou Yinhai Aluminum Co. Ltd.Liuzhou 545006China

The hot deformation behavior of AA5083 aluminum alloy was studied using isothermal compression tests with a Gleeble 3500 thermal simulator at strain rate of 0.0110 s 1 and at temperature of 300500°*** experimental results indicate that dynamic recrystallization(DRX)tends to occur at high strain rates and temperatures,and therefore the flow stress is *** predict the flow behavior under different deformation conditions,a strain-compensated constitutive equation based on Arrhenius-type equation and Zener Hollomon parameters was *** flow stresses obtained from the constitutive equation are consistent with the experimental *** average absolute relative error is only 4.52%over the entire experimental range,indicating that the proposed constitutive equation exhibits high prediction precision for the hot deformation behavior of AA5083 aluminum alloy.

关键词： hot deformation AA5083 dynamic recrystallization constitutive equation

Enhanced Fenton-like process over Cu/L(+)-ascorbic acid co-doping mesoporous silica for toxicity reduction of emerging contaminants

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Frontiers of Environmental Science & Engineering 2024年第4期18卷 49-60页

作者： Yuhang Liu Wenxuan deng Xiaojun Wu Chun Hu lai Lyu Key Laboratory for Water Quality and Conservation of the Pearl River Delta(Ministry of Education) Institute of Environmental Research at Greater BayGuangzhou UniversityGuangzhou 510006China

Effective removal of emerging contaminants(ECs)to minimize their impacts on human health and the natural environment is a global *** the removal of ECs in water,we fabricated a seaweed spherical microsphere catalyst with Cu cation-πstructures by in situ doping of Cu species and ascorbic acid in mesoporous silica(Cu-C-MSNs)via a hydrothermal *** results indicate that bisphenol A(BPA)is substantially degraded within 5 min under natural conditions,with its biological toxicity considerably ***,industrial wastewater could also be effectively purified by Cu-C-MSNs/H_(2)O_(2) *** presence of metal sites and the complexation of ECs via cation-πinteraction andπ-πstacking on the catalyst surface were directly responsible for the polarization distribution of electrons,thus activating H_(2)O_(2) and dissolved oxygen(DO).The removal of contaminants could be attributed primarily to 1)the activation of H_(2)O_(2) into ^(·)OH to attack the contaminants and 2)self-cleavage because of the transfer of electrons from the contaminants to the *** study provides an innovative solution for the effective treatment of ECs and has positive implications for easing global environmental crises.

关键词： Cation-πstructures Polarization electric field Fenton-like process Contaminants cleavage

The synthetic gauge field and exotic vortex phase with spin-orbital-angular-momentum coupling

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Communications in Theoretical Physics 2024年第8期76卷 52-59页

作者： Yingqi Liu yun Chen Yuangang deng Guangdong Provincial Key Laboratory of Quantum Metrology and Sensing&School of Physics and Astronomy Sun Yat-Sen University(Zhuhai Campus)Zhuhai 519082China

Ultracold atoms endowed with tunable spin-orbital-angular-momentum coupling(SOAMC)represent a promising avenue for delving into exotic quantum phenomena. Building on recent experimental advancements, we propose the generation of synthetic gauge fields, and by including exotic vortex phases within spinor Bose-Einstein condensates, employing a combination of a running wave and Laguerre-Gaussian laser fields. We investigate the ground-state characteristics of the SOAMC condensate, revealing the emergence of exotic vortex states with controllable orbital angular momenta. It is shown that the interplay of the SOAMC and conventional spin-linear-momentum coupling induced by the running wave beam leads to the formation of a vortex state exhibiting a phase stripe hosting single multiply quantized singularity. The phase of the ground state will undergo the phase transition corresponding to the breaking of rotational symmetry while preserving the mirror symmetry. Importantly, the observed density distribution of the ground-state wavefunction, exhibiting broken rotational symmetry, can be well characterized by the synthetic magnetic field generated through light interaction with the dressed spin state. Our findings pave the way for further exploration into the rotational properties of stable exotic vortices with higher orbital angular momenta against splitting in the presence of synthetic gauge fields in ultracold quantum gases.

关键词： ultracold atoms synthetic gauge fields vortex phases spin-orbital-angularmomentum coupling

Tetrathiafulvalene esters with high redox potentials and improved solubilities for non-aqueous redox flow battery applications

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Green Energy & Environment 2024年第5期9卷 899-908页

作者： Weikang Hu Jiaqi Xu Nanjie Chen Zongcai deng Yuekun lai Dongyang Chen College of Materials Science and Engineering Fuzhou UniversityFuzhou350116China College of Chemical Engineering Fuzhou UniversityFuzhou350116China

The exploitation of high performance redox-active substances is critically important for the development of non-aqueous redoxﬂow ***,three tetrathiofulvalene(TTF)derivatives with different substitution groups,namely TTF diethyl ester(TTFDE),TTF tetramethyl ester(TTFTM),and TTF tetraethyl ester(TTFTE),are prepared and their energy storage properties are *** has been found that the redox potential and solubility of these TTF derivatives in conventional carbonate electrolytes increases with the number of ester *** battery with a catholyte of 0.2 mol L^(-1) of TTFTE delivers a speciﬁc capacity of more than 10 Ah L^(-1) at the current density of 0.5 C with two discharge voltage platforms locating at as high as 3.85 and 3.60 V ***/Liþ.Its capacity retention can be improved from 2.34 Ah L^(-1) to 3.60 Ah L^(-1) after 100 cycles by the use of an anion exchange membrane to block the crossover of TTF *** excellent cycling stability of the TIF esters is supported by their well-delocalized electrons,as revealed by the density function theory ***,the introduction of more and larger electron-withdrawing groups is a promising strategy to simultaneously increase the redox-potential and solubility of redox-active ma-terials for non-aqueous redoxﬂow batteries.

关键词： Non-aqueous redox flow batteries Tetrathiofulvarene Redox potential Solubility Substituent effect

Special issue on electrochemical energy storage and conversion

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Frontiers in Energy 2024年第2期18卷 125-127页

作者： yun ZHENG Gaixia ZHANG Sixu deng Jiujun ZHANG Institute of New Energy Materials and Engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China Department of Electrical Engineering École de Technologie Supérieure(ÉTS)Universitédu QuébecMontréalH3C 1K3Canada Department of Chemical and Materials Engineering Concordia UniversityMontrealQC H3G 1M8Canada

The escalating global consumption of fossil fuels has significantly elevated the levels of CO_(2)in the atmosphere,leading to an undesirable global energy crisis and environmental *** deployment of renewable energy resources is crucial to mitigate these *** recent years,there has been noteworthy progress in electrochemical energy storage and conversion techniques and devices,including hydrogen energy and fuel cells,advanced energy storage and power batteries,and CO_(2)electrochemical conversion and utilization.

关键词： electrochemical energy elevated

Quenching sensitivity and heterogeneous precipitation behavior of AA7136 alloy

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Transactions of Nonferrous Metals Society of China 2021年第11期31卷 3356-3369页

作者： Zhi-min MA Yong ZHANG Sheng-dan LIU yun-lai deng Xin-ming ZHANG School of Materials Science and Engineering Central South UniversityChangsha 410083China Baotou Vocational&Technical College Baotou 014030China Key Laboratory of Non-ferrous Metals Materials Science and Engineering Ministry of EducationCentral South UniversityChangsha 410083China

The quenching sensitivity of AA7136 alloy was investigated by time−temperature−property(TTP)diagrams,and the heterogeneous precipitation behavior during isothermal holding was investigated using scanning electron microscopy,scanning transmission electron microscopy and high resolution transmission electron *** on 99.5%TTP diagram,the nose temperature is determined to be about 346℃ with the transformation time of about 0.245 *** precipitation ofη(MgZn_(2)),T(Al_(2)Zn_(3)Mg_(3)),S(Al_(2)CuMg)or Cu−Zn-rich Y phases can be found depending on isothermal holding temperature and time,and it is described in a time−temperature−precipitation *** size and area fraction of isothermal holding induced phase particles increase,which results in the decrease of hardness of samples after *** quantitative contribution to loss of hardness by grain boundaries/subgrain boundaries and dispersoids in the matrix is discussed based on the amount of heterogeneous precipitation related to them.

关键词： AA7136 alloy quenching sensitivity time−temperature−property diagrams heterogeneous precipitation

Optimal mining sequence for coal faces under a bedding slope:insight from landslide prevention

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Journal of Mountain Science 2024年第5期21卷 1775-1798页

作者： LI Qingmiao ZHAO Jianjun LI Zhichao deng Jie ZUO Jing lai Qiyi State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China

Repetitive mining beneath bedding slopes is identified as a critical factor in geomorphic disturbances, especially landslides and surface subsidence. Prior research has largely concentrated on surface deformation in plains due to multi-seam coal mining and the instability of natural bedding slopes, yet the cumulative impact of different mining sequences on bedding slopes has been less explored. This study combines drone surveys and geological data to construct a comprehensive three-dimensional model of bedding slopes. Utilizing FLAC3D and PFC2D models, derived from laboratory experiments, it simulates stress, deformation, and failure dynamics of slopes under various mining sequences. Incorporating fractal dimension analysis, the research evaluates the stability of slopes in relation to different mining sequences. The findings reveal that mining in an upslope direction minimizes disruption to overlying strata. Initiating extraction from lower segments increases tensile-shear stress in coal pillar overburdens, resulting in greater creep deformation towards the downslope than when starting from upper segments, potentially leading to localized landslides and widespread creep deformation in mined-out areas. The downslope upward mining sequence exhibits the least fractal dimensions, indicating minimal disturbance to both strata and surface. While all five mining scenarios maintain good slope stability under normal conditions, recalibrated stability assessments based on fractal dimensions suggest that downslope upward mining offers the highest stability under rainfall, contrasting with the lower stability and potential instability risks of upslope downward mining. These insights are pivotal for mining operations and geological hazard mitigation in multi-seam coal exploitation on bedding slopes.

关键词： Bedding rock landslides Mining-induced deformation Bedding slope stability Underground mining sequences Fractal-based strength reduction method

A unified Minorization-Maximization approach for estimation of general mixture models

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 343-362页

作者： HUANG Xi-fen LIU deng-ge ZHOU yun-peng ZHU Fei School of Mathematics Yunnan Normal UniversityKunming 650092China Department of Statistics and Actuarial Science The University of Hong KongHong KongChina

The mixed distribution model is often used to extract information from heteroge-neous data and perform modeling *** the density function of mixed distribution is complicated or the variable dimension is high,it usually brings challenges to the parameter es-timation of the mixed distribution *** application of MM algorithm can avoid complex expectation calculations,and can also solve the problem of high-dimensional optimization by decomposing the objective *** this paper,MM algorithm is applied to the parameter estimation problem of mixed distribution *** method of assembly and decomposition is used to construct the substitute function with separable parameters,which avoids the problems of complex expectation calculations and the inversion of high-dimensional matrices.

关键词： MM algorithm mixed distribution model parameter estimation assembly decomposition tech-nology parameter separation