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Study on static characteristics of a novel prestress-reinforced railway subgrade

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Railway Engineering Science 2025年第1期33卷 108-126页

作者： Junli Dong Fang Xu Qishu Zhang Wuming Leng Yafeng Li Qi Yang School of Civil Engineering Central South UniversityChangsha 410075China MOE Key Laboratory of Engineering Structures of Heavy Haul Railway Central South UniversityChangsha 410075China School of Civil Engineering Central South University of Forestry and TechnologyChangsha 410004China School of Civil Engineering and Architecture Anhui University of Science and TechnologyHuainan 232001China

Understanding the reinforcement effect of the newly developed prestressed reinforcement components(PRCs)(a system composed of prestressed steel bars(PSBs),protective sleeves,lateral pressure plates(LPPs),and anchoring elements)is technically significant for the rational design of prestressed subgrade.A three-dimensional finite element model was established and verified based on a novel static model test and utilized to systematically analyze the influence of prestress levels and reinforcement modes on the reinforcement effect of the *** results show that the PRCs provide additional confining pressure to the subgrade through the diffusion effect of the prestress,which can therefore effectively improve the service performance of the *** to the unreinforced conventional subgrades,the settlements of prestressreinforced subgrades are *** settlement attenuation rate(Rs)near the LPPs is larger than that at the subgrade center,and increasing the prestress positively contributes to the stability of the subgrade *** the multi-row reinforcement mode,the reinforcement effect of PRCs can extend from the reinforced area to the unreinforced *** addition,as the horizontal distance from the LPPs increases,the additional confining pressure converted by the PSBs and LPPs gradually diminishes when spreading to the core load bearing area of the subgrade,resulting in a decrease in the *** the singlerow reinforcement mode,PRCs can be strategically arranged according to the local areas where subgrade defects readily occurred or observed,to obtain the desired reinforcement ***,excessive prestress should not be applied near the subgrade shoulder line to avoid the shear failure of the subgrade *** can be flexibly used for preventing and treating various subgrade defects of newly constructed or existing railway lines,achieving targeted and classified prevention,and effectively improving the bearing performance and deformati

关键词： Prestressed subgrade Static characteristic Reinforcement effect Reinforcement mode Settlement Numerical simulation

Engineering nanoparticle structure at synergistic Ru-Na interface for integrated CO_(2)capture and hydrogenation

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Journal of Energy Chemistry 2025年第1期100卷 779-791页

作者： Hanzi Liu Ling Cen Xinlin Xie Lei Liu Zhao Sun Zhiqiang Sun Hunan Engineering Research Center of Clean and Low-Carbon Energy technology School of Energy Science and EngineeringCentral South UniversityChangsha 410083HunanChina

The development of dual functional material for cyclic CO_(2)capture and hydrogenation is of great significance for converting diluted CO_(2)into valuable fuels,but suffers from kinetic limitation and deactivation of adsorbent and ***,we engineered a series of RuNa/γ-Al_(2)O_(3)materials,varying the size of ruthenium from single atoms to clusters/*** coordination environment and structure sensitivity of ruthenium were quantitatively investigated at atomic *** findings reveal that the reduced Ru nanoparticles,approximately 7.1 nm in diameter with a Ru-Ru coordination number of 5.9,exhibit high methane formation activity and selectivity at 340°*** Ru-Na interfacial sites facilitate CO_(2)migration through a deoxygenation pathway,involving carbonate dissociation,carbonyl formation,and ***-situ experiments and theoretical calculations show that stable carbonyl intermediates on metallic Ru nanoparticles facilitate heterolytic C–O scission and C–H bonding,significantly lowering the energy barrier for activating stored CO_(2).

关键词： CO_(2)capture Hydrogenation Ru-Na interface Dual functional material Reaction mechanism

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Comprehensive recovery of rare earth elements and gypsum from phosphogypsum:A wastewater free process combining gravity separation and hydrometallurgy

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Journal of Rare Earths 2025年第2期43卷 362-370页

作者： Jialin Qing Dapeng Zhao Li Zeng Guiqing Zhang Liang Zhou Jiawei Du Qinggang Li Zuoying Cao Shengxi Wu School of Metallurgy and Environment Central South University Key Laboratory of Metallurgical Separation Science and Engineering of Non-ferrous Metals Industry Central South University National Engineering Laboratory for Efficient Utilization of Refractory Non-ferrous Metals Resources Central South University

Comprehensive utilization of phosphogypsum（PG） has attracted much attention,especially for the recovery of rare earth elements（REEs） and gypsum due to the issues of stockpile,environmental pollution,and waste of associated *** utilization methods suffered the issues of low REEs leaching efficiency,huge amount of CaSO4saturated wastewater and high recovery *** solve these issues,this study investigated the occurrence of REEs in PG and the leaching of *** results show that REEs in PG are in the forms of（1） REEs mineral inclusions,（2） REEs isomorphous substitution of Ca2+in gypsum lattice,（3） dispersed soluble REEs *** leaching results demonstrate that（1） the dissolution of gypsum matrix is the control factor of REEs leaching;（2） H2SO4is a promising leachant considering the recycle of leachate;（3） the gypsum matrix suffers a recrystallization during the acid leaching and releases the soluble REEs from PG to aqueous *** the recovery of the undissolved REEs mineral inclusions,wet sieving concentrated 37.1 wt% of the REEs in a 10.7 wt% mass,increasing REEs content from 309 to 1071 ***,a green process combining gravity separation and hydrometallurgy is *** process owns the merits of wastewater free,considerable REEs recovery（about 10% increase compared with traditional processes）,excellent gypsum purification（>95 wt%CaSO4·2H2O,with <0.06 wt% of soluble P2O5and <0.015 wt% of soluble F） and reagent saving（about 2/3less reagent consumption than non-cyclical leaching）.

关键词： Gravity separation Phosphogypsum Rare earths Recrystallization reinforcement Wastewater free

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Different fates of Sb(Ⅲ)and Sb(V)during the formation of jarosite mediated by Acidithiobacillus ferrooxidans

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Journal of Environmental Sciences 2025年第1期147卷 342-358页

作者： Lu Chen Yirong Wang Hongchang Liu Yuhang Zhou Zhenyuan Nie Jinlan Xia Wensheng Shu School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China Key Lab of Biometallurgy of Ministry of Education of China Central South UniversityChangsha 410083China School of Life Sciences South China Normal UniversityGuangzhou 510631China

Secondary iron-sulfate minerals such as jarosite,which are easily formed in acid mine drainage,play an important role in controlling metal *** this work,the typical iron-oxidizing bacterium Acidithiobacillus ferrooxidans ATCC 23270 was selected to synthesize jarosite in the presence of antimony ions,during which the solution behavior,synthetic product composition,and bacterial metabolism were *** results show that in the presence of Sb(V),Fe^(2+)was rapidly oxidized to Fe^(3+)by *** and Sb(V)had no obvious effect on the biooxidation of Fe^(2+)under the current experimental *** presence of Sb(Ⅲ)inhibited bacterial growth and Fe^(2+)*** the group with Sb(Ⅲ),products with amorphous phaseswere formed 72 hr later,whichwere mainly ferrous sulfate and pentavalent antimony oxide,and the amorphous precursor was finally transformed into a more stable crystal *** the group with Sb(V),the morphology and structure of jarosite were changed in comparison with those without *** biomineralization process was accompanied by the removal of 94%Sb(V)to form jarosite containing the Fe-Sb-O *** transcriptome analysis shows differential effects of Sb(Ⅲ)and Sb(V)on bacterial *** expression levels of functional genes related to cell components were much more downregulated for the group with Sb(Ⅲ)butmuch more regulated for that with Sb(V).Notably,cytochrome c and nitrogen fixation-relevant genes for the A.f_Fe^(2+)_Sb(Ⅲ)group were enhanced significantly,indicating their role in Sb(Ⅲ)*** study is of great value for the development of antimony pollution control and remediation technology.

关键词： Jarosite Acidithiobacillus ferrooxidans Bacterial iron oxidation Sb(Ⅲ)and Sb(V)transformation Transcriptome analysis

Discovery of a new family member of arsenic–vanadium polyoxometalates with high catalytic performance for one-pot coupling of CO2, epoxides and amines

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Tungsten 2025年第1期7卷 80-87页

作者： Fang-Qian Wang Yin Zhang Wei-Wei Wang Mei-Qian Fu Hong-Bing Mo Wei-Dong Yu Chao Liu Jun Yan College of Chemistry and Chemical Engineering Central South University Junior Education Department Changsha Normal University School of Science Hunan University of Technology and Business

Arsenic-vanadium polyoxometalates（POMs） represent a family of tremendous potential catalysts owing to their peculiar physical and chemical *** in CO2conversion,using POMs to catalyze the conversion of CO2and epoxide into chemical intermediates is the research ***,A new family number of arsenic-vanadium POMs,[N（CH3）4]4[As8V12O38（H2O）]·2H2O({As8V12O38}),was reported and characterized by single-crystal X-ray diffraction,fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,*** from other allotropicity,{As8V12O38}shows a different structure pattern with an I-43d *** obtained {As8V12O38} was employed as a catalyst for the *** initial catalytic reaction confirmed that {As8V12O38} can catalyze the formation of epoxy carbonate by using 1.01 kPa CO2and epoxide at 70℃.Furtherly,when added amine in the catalytic system,oxazolidinone could be obtained by high yields,which provides an efficient way to convert CO2into profitable ***,a possible catalytic reaction mechanism was proposed by using different characterization analyses.{As8V12O38} first catalyzes the epoxide and CO2to form an epoxy carbonate and then catalyzes epoxy carbonate and benzylamine into oxazolidinone.

关键词： Arsenic CO2 conversion Oxazolidinone Polyoxometalates Vanadium

Leaching of WO_(3)from sulfuric acid converted product of scheelite in NH_(3)·H_(2)O−NH_(4)HCO_(3)solution

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Transactions of Nonferrous Metals Society of China 2025年第1期35卷 326-337页

作者： Lei-ting SHEN Yu LIU Juan-lang GUO Qiu-sheng ZHOU Tian-gui QI Zhi-hong PENG Gui-hua LIU Xiao-bin LI School of Metallurgy and Environment Central South UniversityChangsha 410083China

The leaching of sulfuric acid converted product of scheelite in NH_(3)·H_(2)O−NH_(4)HCO_(3)solution was systemically studied to improve sulfuric acid conversion−ammonium salts leaching technology route for ammonium paratungstate *** results showed that the WO_(3)leaching efficiency was about 99%under optimal conditions of 350 r/min,liquid-to-solid ratio of 3 mL/g,1 mol/L NH_(4)HCO_(3),4 mol/L NH_(3)·H_(2)O,25℃,and 15 *** the leaching,CaSO_(4)almost had no change and was still in a banding or rod-like shape in short leaching time,while conglobate CaCO_(3)was gradually formed on the CaSO_(4)surface.A secondary reaction might occur between CaSO_(4)and WO_(4)^(2−),which could be restrained by a certain amount of CO_(3)^(2−)in the *** was no CaCO_(3)phase determined by XRD in leaching residue of converted product for scheelite concentrate under optimal conditions,which was different from that for synthetic *** leaching process could be explained by neutralization reaction of H_(2)WO_(4)and solid transformation of CaSO_(4)in NH_(3)·H_(2)O−NH_(4)HCO_(3)solution.

关键词： tungstic acid calcium sulfate leaching mechanism calcium carbonate ammonium tungstate

Uncovering the oxidation mechanism of sphalerite(ZnS)in the absence and presence of water:A first-principles investigation

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International Journal of Mining Science and technology 2025年第1期35卷 149-157页

作者： Yuanjia Luo Wei Sun Haisheng Han Jian Peng Feng Jiang School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China

Herein,a first-principles investigation was innovatively conducted to research the surface oxidation of ZnS-like sphalerite in the absence and presence of H_(2)O .The findings showed that single O_(2) was preferred to be dissociated adsorption on sphalerite surface by generating SAO and Zn AO bonds,and the S atom on the surface was the most energy-supported site for O_(2) adsorption,on which a≡Zn-O-S-O-Zn≡structure will be ***,dissociated adsorption of single H_(2)O will not *** was preferred to be adsorbed on the top Zn atom on sphalerite surface in molecular form through Zn-O ***,sphalerite oxidation can occur as if O_(2) was present regardless of the presence of H_(2)O ,and when H_(2)O and O_(2) coexisted,the formation of sulfur oxide(SO_(2) )needed a lower energy barrier and it was easier to form on sphalerite surface than that only O_(2) *** the absence of H_(2)O ,when SO_(2) was generated,further oxidation of which would form neutral zinc *** the presence of H_(2)O ,the formation of SO_(2) on sphalerite surface was easier and the rate of further oxidation to form sulfate was also ***,the occurrence of sphalerite oxidation was accelerated.

关键词： First-principles Oxidation Sphalerite H_(2)O Lower energy barrier

Understanding the iodine electrochemical behaviors in aqueous zinc batteries

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Journal of Energy Chemistry 2025年第2期101卷 402-415页

作者： Xuefang Xie Xiaoxin Xu Shuquan Liang Guozhao Fang College of Physical Science and technology Xinjiang University Xinjiang Key Laboratory of Solid State Physics and Devices Xinjiang University School of Materials Science & Engineering Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan Province Central South University National Energy Metal Resources and New Materials Key Laboratory Central South University

Iodine is widely used in aqueous zinc batteries（ZBs） due to its abundant resources,low cost,and active redox *** addition to the active material in zinc-iodine batteries,iodine also plays an important role in other ZBs,such as regulating the electrochemical behavior of zinc ions,promoting the reaction kinetic and reversibility of other redox pairs,catalytic behaviors related to iodine reactions,coupling with other halogen ions,shuttle behaviors of polyiodides,***,there is currently a lack of comprehensive discussion on these ***,this review provides a comprehensive overview of the electrochemical behaviors of iodide in the aqueous *** effect of iodine ions on the Zn2+desolvation behaviors and the interfacial behaviors of Zn anode was *** redox pairs boosting other redox pairs,such as MnO2/Mn2+redox pair and vanadium redox pair to obtain high reversibility and capacity was also ***,the catalytic behaviors related to iodine reactions in aqueous ZBs,synergistic reaction with other halogen ions and suppression of shuttle behaviors for high performance zinc-iodine batteries were systematically ***,future prospects for designing effective iodine electrochemical behaviors with practicability are proposed,which will provide scientific guidance for the practical application of iodine-related aqueous ZBs.

关键词： Catalytic behavior Iodide ion Redox pairs Shuttle effect Zinc batteries

Bond length and interface failure mechanism of anchor cable under continuous radial pressure conditions

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International Journal of Mining Science and technology 2025年第2期35卷 231-247页

作者： Jian Ouyang Xiuzhi Shi Xianyang Qiu Zongguo Zhang Zeyu Li School of Resources and Safety Engineering Central South UniversityChangsha 410083China

The anchoring capacity of the anchor cable is closely related to the bonding length and radial pressure *** field pull-out tests,theoretical analysis,numerical simulation,and industrial tests,this study clarifies the relationship between radial pressure and bonding length for the ultimate pullout force and reveals the microscopic failure process of the resin-rock interface in the anchoring *** results show that the ultimate load increases with the increase of bonding length in three different stages:rapid,slow,and uniform *** new mechanical model developed considering radial pressure describes the inverse relationship between radial pressure and the plastic zone on the bonding section,and quantifies the reinforcing effect of confining pressure on the anchoring *** the pull-out process of the anchor cable,the generation of failure cracks is in the order of orifice,bottom,and middle of the *** pressure can effectively enhance the ultimate pull-out force,alleviate the oscillation increase of pull-out force,and inhibit resin cracking,but will produce an external crushing *** also reveals the synergistic effect between bonding length and radial pressure,and successfully carries out industrial tests of anchor cable support,which ensures the stability of the stope roof and provides an important reference for the design of anchor cable support in deep high-stress mines.

关键词： Radial pressure Anchor cable Bond length Numerical simulation Interface failure Microscopic process