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A state-of-the-art review on delayed expansion of cemented paste backfill materials

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Rare metals 2024年第8期43卷 3475-3500页

作者： meng-Yuan Li Li-Jie Guo Yue Zhao Lei Zhang Kai Yang Xiao-peng peng Andrew Pan BGRImm Technology Group Beijing 100160China National Centre for International Research On Green metal mining Beijing102628China Department of Civil and mineral Engineering University of TorontoTorontoON M5S 1A4Canada

Utilizing delayed expansion cemented paste backfill materials(DECPB) in mine backfill operations offers an effective solution to the challenge of achieving proper contact between the in-situ cemented backfill mass and the roof in mined-out areas(backfill-roof contact).This article presents recent progress in both theoretical and experimental research concerning *** types and mechanisms of expansive additives,including expansive agents,foaming agents,and expansive mineral materials relevant to DECPB,are explained,along with their impact on the expansive properties and mechanical characteristics of *** composition,material characteristics,preparation methods,and controlled release mechanisms of microcapsules are *** methods for measuring the volume change rate of paste backfill slurries are *** indicates that an appropriate content of expansive additives not only enhances the expansive properties of cemented paste backfill materials but also contributes to improving their mechanical *** foaming agents and bentonite are found to be more suitable for preparing DECPB compared to expansive *** delayed expansion of cemented paste backfill material is influenced by microcapsules,with their wall materials,preparation parameters,and the alkaline slurry environment affecting their controlled release *** and optimizing precise measurement devices and methods forfor the volume change rate of cemented paste backfill materials is essential requirement for studying the performance of *** delayed expansion technology with retarding techniques in cemented paste backfill materials can provide a reliable solution for achieving proper backfill-roof contact in the future.

关键词： Paste backfill Delayed expansion mining with backfill Expansive additives Tailings

A new insight into LPSO phase transformation and mechanical properties uniformity of large-scale mg-Gd-Y-Zn-Zr alloy prepared by multi-pass friction stir processing

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Journal of magnesium and Alloys 2024年第5期12卷 2041-2056页

作者： Xiaohu Guan Wen Wang Ting Zhang Pai peng Qiang Liu peng Han Ke Qiao Jun Cai Liqiang Wang Kuaishe Wang School of metallurgical Engineering National and Local Joint Engineering Research Center for Functional Materials ProcessingXi’an University of Architecture and TechnologyNo.13 Yanta RoadXi’anShaanxi 710055China Xi’an Rare metal materials Institute Co.Ltd Xi’an 710016China State Key Laboratory of metal matrix Composites School of Material Science and EngineeringShanghai Jiao Tong UniversityNo.800 Dongchuan RoadShanghai 200240China

A large-scale fine-grained mg-Gd-Y-Zn-Zr alloy plate with high strength and ductility was successfully prepared by multi-pass friction stir processing(mFSP)technology in this *** structure of grains and long period stacking ordered(LPSO)phase were characterized,and the mechanical properties uniformity was ***,a quantitative relationship between the microstructure and tensile yield strength was *** results showed that the grains in the processed zone(PZ)and interfacial zone(IZ)were refined from 50μm to 3μm and 4μm,respectively,and numerous original LPSO phases were *** IZ,some block-shaped 18R LPSO phases were transformed into needle-like 14H LPSO phases due to stacking faults and the short-range diffusion of solute *** severe shear deformation in the form of kinetic energy caused profuse stacking fault to be generated and move rapidly,greatly increasing the transformation rate of LPSO *** mFSP,the ultimate tensile strength,yield strength and elongation to failure of the large-scale plate were 367 mPa,305 mPa and 18.0% *** refinement and LPSO phase strengthening were the major strengthening mechanisms for the mFSP *** particularly,the strength of IZ was comparable to that of PZ because the strength contribution of the 14H LPSO phase offsets the lack of grain refinement strengthening in *** result opposes the widely accepted notion that IZ is a weak region in mFSP-prepared large-scale fine-grained plate.

关键词： Friction stir processing multi-pass mg-Gd-Y-Zn-Zr alloy LPSO phase transformation mechanical properties

Influence of layer thickness on formation quality,microstructure,mechanical properties,and corrosion resistance of WE43 magnesium alloy fabricated by laser powder bed fusion

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Journal of magnesium and Alloys 2024年第4期12卷 1367-1385页

作者： Bangzhao Yin Jinge Liu Bo peng mengran Zhou Bingchuan Liu Xiaolin ma Caimei Wang peng Wen Yun Tian Yufeng Zheng State Key Laboratory of Tribology in Advanced Equipment Beijing100084China Department of mechanical Engineering Tsinghua UniversityBeijing 100084China Institute for Precision medicine Tsinghua UniversityBeijing102218China Department of Orthopaedics Peking University Third HospitalBeijing 100191China Beijing AKEC medical Co. Ltd.Beijing 102200China School of materials Science and Engineering Peking UniversityBeijing 100871China Engineering Research Center of Bone and Joint Precision medicine Ministry of EducationBeijing 100191China

Laser powder bed fusion(L-PBF)of mg alloys has provided tremendous opportunities for customized production of aeronautical and medical *** thickness(LT)is of great significance to the L-PBF process but has not been studied for mg *** this study,WE43 mg alloy bulk cubes,porous scaffolds,and thin walls with layer thicknesses of 10,20,30,and 40μm were *** required laser energy input increased with increasing layer thickness and was different for the bulk cubes and porous *** tended to occur at the connection joints in porous scaffolds for LT40 and could be eliminated by reducing the laser energy *** thin wall parts,a large overhang angle or a small wall thickness resulted in porosity when a large layer thicknesses was used,and the porosity disappeared by reducing the layer thickness or laser energy input.A deeper keyhole penetration was found in all occasions with porosity,explaining the influence of layer thickness,geometrical structure,and laser energy input on the *** the samples achieved a high fusion quality with a relative density of over 99.5%using the optimized laser energy *** increased layer thickness resulted to more precipitation phases,finer grain sizes and decreased grain *** the similar high fusion quality,the tensile strength and elongation of bulk samples were significantly improved from 257 mPa and 1.41%with the 10μm layer to 287 mPa and 15.12%with the 40μm layer,in accordance with the microstructural *** effect of layer thickness on the compressive properties of porous scaffolds was ***,the corrosion rate of bulk samples accelerated with increasing the layer thickness,mainly attributed to the increased number of precipitation phases.

关键词： magnesium alloy WE43 Laser powder bed fusion Layer thickness Process optimization

The Extension Dimension of Subcategories and Recollements of Abelian Categories

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Acta mathematica Sinica,English Series 2024年第4期40卷 1042-1058页

作者： Xin mA Ye Yang peng Zhao Yong HUANG College of Science Henan University of EngineeringZhengzhou 451191P.R.China Department of mathematics Nanjing UniversityNanjing 210093P.R.China

We investigate the behavior of the extension dimension of subcategories of abelian categories under ***Λ',Λ,Λ"be art in algebras such that(modΛ',mod A,modΛ")is a recollement,and let D'and D"be subcategories of modΛand modΛ"*** any n,m≥0,under some conditions,we get dimΩ^(k)(D)≤dimΩ^(n)(D')+dimΩ^(m)(D")+1,where k=max{m,n}and D is the subcategory of modΛglued by D'and D";moreover,we give a sufficient condition such that the converse inequality holds *** applications,some results for Igusa-Todorov subcategories and syzygy finite sub categories are obtained.

关键词： Recollements extension dimension Igusa–Todorov subcategories syzygy finite subcategories

Effects of physical crust on soil detachment by overland flow in the Loess Plateau region of China

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International Soil and Water Conservation Research 2024年第1期12卷 107-120页

作者： Jiaxin Liu Liding Chen Bing Wang Xiaoyu peng School of Ecology and Environmental Science Yunnan UniversityKunming650091China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F UniversityYanglingShaanxi712100China University of Chinese Academy of Sciences Beijing100049China

Physical soil crust(PSC),a key component of surface soil structure,exists extensively in loess *** is considered to have a significant effect on soil detachment ***,the long-term effects and the corresponding mechanisms of PSC on soil detachment by overland flow are still not well understood,especially in natural *** investigate temporal variation in soil erosion resistance and the underlying factors during PSC formation,an 8×8-m soil plot was exposed to natural conditions in the Loess Plateau over a 524-day period spanning two rainy seasons and a winter between them.A flume test was conducted to determine soil detachment capacity(Dc)under six designed flow shear stress levels(5.66-22.11 Pa)using crusted(SC)and non-crusted(NSC)soil samples at different PSC development ***,two soil erosion resistance parameters,rill erodibility(K_(r))and critical shear stress(τ_(c)),were *** time,in the SC and NSC treatments,K_(r)decreased from 0.516 to 0.120 s m^(-1)and 0.521 to 0.223 s m^(-1),respectively,whileτ_(c)increased from 0.49 to 4.42 Pa and 0.26-2.46 Pa,*** in soil erosion resistance was rapid in the first one to two months,and then slowed down,with slight fluctuations *** the SC treatment,K_(r)was 42%lower andτ_(c)was 67%greater than those in the NSC *** properties changed greatly for both *** increased from 0 to 7.09 mm in the SC *** increased from 2.91 to 9.04 kPa and 3.01-4.78 kPa in SC and NSC treatments,*** soil erosion resistance parameters could be well predicted by SCT and Coh in the SC treatment(R^(2)≥0.82),while their best predictor was Coh in the NSC treatment(R^(2)≥0.90).The results demonstrate that PSC formation enhances soil erosion resistance in the soil detachment process in the loess region under natural *** study revealed the important role and complexity of PSC in the process of soil erosion,and provided theor

关键词： Physical soil crust formation Soil heterogeneity Rill erodibility Critical shear stress

Silvery fullerene in Ag102 nanosaucer

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National Science Review 2024年第7期11卷 158-167页

作者： Zhi Wang Yuchen Wang Chengkai Zhang Yan-Jie Zhu Ke-peng Song Christine m.Aikens Chen-Ho Tung Di Sun School of Chemistry and Chemical Engineering Shandong University Department of Chemistry Kansas State University

Despite the discovery of a series of fullerenes and a handful of noncarbon clusters with the typical topology of Ih-C60, the smallest fullerene with a large degree of curvature, C20, and its other-element counterparts are difficult to isolate experimentally. In coinage metal nanoclusters（NCs）, the first all-gold fullerene, Au32, was discovered after a long-lasting pursuit, but the isolation of similar silvery fullerene structures is still challenging. Herein, we report a flying saucer-shaped 102-nuclei silver NC（Ag102） with a silvery fullerene kernel of Ag32, which is embraced by a robust cyclic anionic passivation layer of（KPO4）10. This Ag32kernel can be viewed as a non-centered icosahedron Ag12encaged into a dodecahedron Ag20, forming the silvery fullerene of Ag12@Ag20. The anionic layer（KPO4）10is located at the interlayer between the Ag32kernel and Ag70shell, passivating the Ag32silvery fullerene and templating the Ag70shell. The ~tBuPhS-and CF3COO-ligands on the silver shell show a regioselective arrangement with the 60 ~tBuPhS-ligands as expanders covering the upper and lower of the flying saucer and 10 CF3COO-as terminators neatly encircling the edges of the structure. In addition, Ag102 shows excellent photothermal conversion efficiency（η） from the visible to near-infrared region（η = 67.1% ± 0.9% at 450 nm, 60.9% ± 0.9% at 660 nm and 50.2% ± 0.5% at 808 nm）, rendering it a promising material for photothermal converters and potential application in remote laser ignition. This work not only captures silver kernels with the topology of the smallest fullerene C20, but also provides a pathway for incorporating alkali metal（m） into coinage metal NCs via m-oxoanions.

关键词： silvery fullerene >Ag102 nanosaucer cyclic anionic passivation layer photothermal conversion DFT calculation

Properties, hazards and valuable metal recovery technologies of red mud: A review

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Particuology 2024年第10期93卷 328-348页

作者： Peixin Du peng Wang Xueqian Zhang Guangwu Wen Yishan Wang School of materials Science and Engineering Shandong University of TechnologyZibo255000China

This review presents a summary of the research conducted thus far on the recovery of various types of valuable metals from red mud. The composition, properties, environmental hazards, and current status of comprehensive utilization of red mud were studied. A number of studies have been conducted on the use of red mud as a modifying additive for cement, the development of various catalysts based on red mud, and the recovery of various valuable metals from red mud. Furthermore, we examine several techniques for extracting various types of valuable metals from red mud, including pyrometallurgical recovery, wet leaching recovery, and emerging biobased technology recovery. We investigate the underlying principles, processes, research progress, and the potential for industrial application of these methods, and assess the advantages and disadvantages of each from the perspectives of economic and environmental benefits. Although these methods have certain disadvantages, in general, the recovery of various types of valuable metals from red mud is an effective way to solve the problem of red mud and the supply of metal raw materials. In conclusion, this paper presents an overview of the current state of red mud development and utilization, as well as the various methods employed for the recovery of valuable metals from red mud.

关键词： Red mud Utilization Environment hazard Valuable metal Recovery

Optimized Selection method of Air Combat Course of Action under Stochastic Uncertainty

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Journal of Systems Science and Systems Engineering 2024年第4期33卷 494-518页

作者： Yun Zhong Jieyong Zhang peng Sun Lujun Wan Kepeng Wang Information and Navigation College Air Force Engineering UniversityXi’an710077China Equipment management and Unmanned Aerial Vehicle Engineering College Air Force Engineering UniversityXi’an710051China Air Traffic Control and Navigation College Air Force Engineering UniversityXi’an710051China Unit 94040 of PLA Korla841000China

Aiming at the design problem of aviation swarm combat course of action(COA),considering the influence of stochastic parameters in the causal relationship model and optimization problem model,according to the dynamic influence net(DIN)theory,stochastic simulation technique,feedforward neural network(FNN)function approximation technique and multi-objective artificial fish school algorithm(mOAFSA),this paper proposed a COA optimized method based on DIN and multi-objective stochastic chance constraint optimization for aviation swarm ***,on the basis of establishing the overall framework of the model and defining the elements of causal relationship modeling,the static and dynamic causal relationship modeling and optimization problem modeling were carried out ***,the probability propagation mechanism of DIN was established,which mainly included two aspects,i.e.,the overall process and the specific ***,input and output data were generated based on stochastic *** to these data,FNN was adopted for function approximation,and mOAFSA was adopted for iterative ***,the rationality of the model,and the effectiveness and superiority of the algorithm were verified through multiple sets of simulation cases.

关键词： Stochastic uncertainty aviation swarm stochastic simulation course of action feedforward neural network multi-objective artificial fish school algorithm

Review on the design of high-strength and hydrogen-embrittlement-resistant steels

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International Journal of minerals,metallurgy and materials 2024年第7期31卷 1572-1589页

作者： Zhiyu Du Rongjian Shi Xingyu peng Kewei Gao Xiaolu Pang Beijing Advanced Innovation Center for materials Genome Engineering School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China Institute for materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110010China

Given the carbon peak and carbon neutrality era,there is an urgent need to develop high-strength steel with remarkable hydrogen embrittlement *** is crucial in enhancing toughness and ensuring the utilization of hydrogen in emerging iron and steel ***,the pursuit of enhanced metallic materials presents a cross-disciplinary scientific and engineering *** high-strength,toughened steel with both enhanced strength and hydrogen embrittlement(HE)resistance holds significant theoretical and practical *** ensures secure hydrogen utilization and further carbon neutrality objectives within the iron and steel *** on the design principles of high-strength steel HE resistance,this review provides a comprehensive overview of research on designing surface HE resistance and employing nanosized precipitates as intragranular hydrogen *** also proposes feasible recommendations and prospects for designing high-strength steel with enhanced HE resistance.

关键词： hydrogen embrittlement surface design hydrogen traps nanosized precipitates