检索结果-南通市图书馆

Cerium oxide inclusion nucleation mechanism based on classical nucleation theory and two-step nucleation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第4期42卷 793-802页

作者： Yutang Li Jun Wang Linzhu Wang Chaoyi Chen Shufeng Yang Junqi Li Xiang Li School of Materials and Metallurgy Guizhou UniversityGuiyang550025China State Key Laboratory of Public Big Data Guizhou UniversityGuiyang550025China School of metallurgical and Ecological engineering University of Science and Technology BeijingBeijing100083China Department of Materials&Metallurgy engineering Guizhou Institute of TechnologyGuiyang550003China

It is challenging to assess the mechanism responsible for the nucleation of inclusions in metals at high *** present work therefore systematically investigates the nucleation of cerium oxide inclusions according to classical nucleation theory and a two-step nucleation *** nucleation rates and nucleation radii of these inclusions are obtained,and the results demonstrate a considerable difference between theoretical and experimental *** the basis of a two-step nucleation mechanism,(CeO_(2))_(n) and(Ce_(2)O_(3))_(n)(n=1-6)clusters were constructed and the thermodynamic properties of both these clusters and of cerium oxide nanoparticles were *** addition,the entropies and heat capacity changes of cerium oxides were determined using first principles calculations and are found to be consistent with literature *** present data indicate that the cerium oxide inclusion nucleation pathway can be summarized as[Ce]+[O]→(CeO_(2))n/(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(2)→core(Ce_(2)O_(3)crystal)-shell((Ce_(2)O_(3))_(2) cluster)nanoparticles→(Ce_(2)O_(3))bulk.

关键词： Cerium oxide inclusion Classical nucleation theory Two-step nucleation mechanism First principles Rare earths

Mineralogical properties and co-sintering characteristics of fluxed iron ore with magnetite concentrates

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第2期31卷 318-328页

作者： Le-le Niu Zheng-jian Liu Jian-liang Zhang Yao-zu Wang Zhen-xing Yang Si-da Li Chang-dong Shan Ben Feng School of metallurgical and Ecological engineering University of Science and Technology BeijingBeijing100083China Institute of Artificial Intelligence University of Science and Technology BeijingBeijing100083China Xinxing Casting Pipe Xinjiang Co. Bayingol841300XinjiangChina

To investigate the feasibility of co-sintering of fluxed iron ore with magnetite concentrates, the mineralogical properties of a novel fluxed iron ore were studied using particle size analysis, microscopic morphology characterization, and X-ray diffraction Rietveld analysis. Following that, the experiments for granulation performance and basic sintering characteristics were designed under seven different fluxed iron ore ratios, and the integrated ranking of different fluxed iron ore ratios was determined using gray relation analysis. Finally, the results of the industrial trails were combined with the feasibility analysis. Test and experimental results show that the fraction of the fluxed iron ore particles larger than 0.5 mm can account for more than 48%, and the particles have two morphologies: spherical-rough and flaky-smooth. Ca elements are found in the form of calcite (CaCO3) and dolomite (CaMg(CO3)2). The average particle size of granules and powder removal rate can be improved from 2.50 to 3.16 mm and 39.60% to 24.20%, respectively, with the increase in the fluxed iron ore ratio. Furthermore, the fluxed iron ore can improve assimilability and liquid fluidity of magnetite concentrates. In terms of overall granulation performance and sintering characteristics, the fluxed iron ore ratios are graded from best to worst as follows: 12%, 15%, 9%, 18%, 21%, 6% and 3%. The industrial trails show that when the fluxed iron ore ratio is increased, the beneficial effect of the superior sintering characteristics of the fluxed iron ore itself is ideally balanced with the negative effect of the lower amount of additional CaO at 12% ratio, and thus, it is feasible to bring the fluxed iron ore into production at a level of roughly 12%.

关键词： Fluxed iron ore Magnetite concentrate Granulation performance Sintering characteristics Gray relation analysis

Recovery of rare earth elements from rare earth molten salt electrolytic slag via fluorine fixation by MgCl2 roasting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第10期42卷 1979-1987页

作者： Minghui Zhang Bingxuan He Yinliang Liu Luewei Xu Yong Liang Faculty of metallurgical engineering Jiangxi University of Science and Technology Key Laboratory of Ionic Rare Earth Resources and Environment Ministry of Natural Resources Jiangxi Provincial Key Laboratory of Green and Low Carbon Metallurgy for Strategic Nonferrous Metals

Rare earth fluoride molten-salt electrolytic slag（REFES） is a precious rare earth element（REE） secondary resource,and conside rable amounts of REEs exist in REFES as REF3;they are difficult to dissolve in acid or water and impede efficient REE *** REFES recovery,the REF3species in REFES are usually transformed into acid-soluble rare earth compounds by NaOH roasting or sulfating roasting and then extracted by acid leaching,Moreover,the fluorides in REFES are released as HF gas in the roasting process or enter the liquid phase during the water washing process;both of these processes cause fluorine *** the fluorine into the solid slag provides a way to avoid fluorine *** this study,a novel method was proposed to extract REEs from REFES via MgCl2roasting followed by HCl *** calculations and the rmogravimetry-differential thermal analyses（TG-DTA） were conducted to investigate the reactions occurring in the roasting process,First,MgCl2reacts with the REF3and RE2O3to form RECl3and REOCl,***,the RECI3absorbs water and forms RE（OH）***,MgCl2·6H2O is gradually dehydrated to MgCl2·2H2O and reacts with REF3and RE（OH）3,and REOCl,MgF2and MgO are *** HCl leaching,the REOCl in the roasting products is leached by HCl acid,while fluoride re mains in the solid slag as *** optimum experimental conditions are as follows:mass ratio of MgCl2to REFES of 30%,roasting temperature of 700℃,roasting time of 2 h,hydrochloride acid concentration of 4 mol/L,leaching time of 2 h,leaching temperature of 90 ℃ and leaching L/S ratio of 20:*** efficiencies for total leaching of the REEs,La,Ce,Pr,and Nd are 99.13%,99.20%,98.42%,99.38%,and 99.08%,***,the concentration of fluoride in the leaching solution is 2.191×10-6mol/*** method has a short process flow with low reagent costs,and the problem of fluoride pollution from REFES recovery is solved;thus,our study has great industrial application pot

关键词： Fluorine Leaching Molten-salt electrolytic slag Rare earths Recovery

Effect of austenitizing condition on mechanical properties,microstructure and precipitation behavior of AISI H13 steel

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第1期31卷 143-156页

作者： An-gang Ning Yang Liu Rui Gao Stephen Yue Ming-bo Wang Han-jie Guo College of Materials Science and engineering Taiyuan University of TechnologyTaiyuan030024ShanxiChina Department of Mining and Materials engineering McGill UniversityMontrealQCH3A 0C5Canada ASSAB Tooling Technology(Chongqing)Co. Ltd.Chongqing401120China School of metallurgical and Ecological engineering University of Science and Technology BeijingBeijing100083China

The effects of austenitizing temperature(1223,1303,and 1373 K)and holding time(1-1500 s)on the microstructure,mechanical properties,and precipitation behavior of the H13 hot work die steel were *** results indicate a softening phenomenon when H13 steel is austenitized at 1303 K beyond 900 s and 1373 K beyond 600 s,*** the sample held for 1200 s,the tensile strength is found capable of reaching up to 2.2 GPa when quenched from a temperature above 1303 ***,prior-austenite grain size increases with the increase in austenitizing *** kinetic behavior of the precipitates(mainly MC-type carbides)in H13 steel could be elaborated through the principles set forth by the Arrhenius and Avrami ***,the comprehensive strengthening of the H13 steel was discussed in *** results show that the activation energy of the transformed fraction of carbides is higher than that of the diffusion process for common alloying elements(Cr,V,Mo,and Ni)found in the *** suggests that it would be difficult for precipitates to dissolve into the matrix when H13 steel is austenitized at high *** the increasing austenitizing temperature,the precipitation fraction decreases,and the dislocation density *** dislocation strengthening is regarded as the dominant strengthening contributed to yield strength in as-quenched H13 steel.

关键词： H13 steel Austenitizing Mechanical property Precipitation behavior Comprehensive strengthening

Wettability modification effects on relative permeability end-points:Comparative analysis of surfactant agents for enhanced oil recovery

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Research 2024年第2期9卷 206-218页

作者： Erfan Hosseini Negar Hosseini Mohammad Sarmadivaleh Exploration Directorate National Iranian Oil Company(NIOC)TehranIran Department of Petroleum engineering Islamic Azad University(IAU)IlamIran WA School of Mines:minerals Energy and Chemical EngineeringCurtin UniversityPerthWestern AustraliaAustralia

This research examines the impact of wettability alteration on the end points of relative permeability,a crucial property of fluids and porous media that influences the displacement processes of immiscible fluids through such *** estimation of the mobility ratio for oil recovery relies on these end points,which are influenced by connate water saturation and residual oil *** investigate this relationship,carbonate rock is generally subjected to wettability alteration using surfactant agents,and core flooding is employed to determine the relative permeability before and after the *** wettability of the rock is commonly assessed through contact angle *** surfactants,TritonX-100(Tx-100)and Cedar,were tested in reducing the wettability of the porous media for *** contact angle measurements revealed that Tx-100 was more effective for this purpose than ***,the relative permeability tests indicated that both surfactants decreased residual oil saturation,but Tx-100 also improved system *** contrast,Cedar reduced residual oil saturation but increased system pressure,possibly because of its high *** results also demonstrate that injecting Tx-100 leads to a 14%increase in ultimate oil recovery compared with water injection,while Cedar injection increased the recovery factor by 5%.This difference may be attributed to the incomplete coverage of the pore wall by Cedar or its weaker chemical structure than ***,in carbonate cores,neither non-ionic surfactant enhanced oil recovery.

关键词： Wettability alteration Relative permeability Core flooding Tx-100 Cedar Contact angle

An Optimization Approach of IoD Deployment for Optimal Coverage Based on Radio Frequency Model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in engineering & Sciences 2024年第6期139卷 2627-2647页

作者： Tarek Sheltami Gamil Ahmed Ansar Yasar Computer engineering Department Interdisciplinary Research Center of Smart Mobility and LogisticsKing Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia Transportation Research Institute(IMOB) Hasselt UniversityHasselt3500Belgium

Recently,Internet of Drones(IoD)has garnered significant attention due to its widespread ***,deploying IoD for area coverage poses numerous limitations and *** include interference between neighboring drones,the need for directional antennas,and altitude restrictions for *** challenges necessitate the development of efficient *** research paper presents a cooperative decision-making approach for an efficient IoDdeployment to address these challenges *** primary objective of this study is to achieve an efficient IoDdeployment strategy thatmaximizes the coverage regionwhile minimizing interference between neighboring *** deployment problem,the interference increases as the number of deployed drones increases,resulting in bad quality of *** the other hand,deploying a few drones cannot satisfy the coverage *** accomplish this,an enhanced version of a concise population-based meta-heuristic algorithm,namely Improved Particle SwarmOptimization(IPSO),is *** objective function of IPSO is defined based on the coverage probability,which is primarily influenced by the characteristics of the antennas and drone altitude.A radio frequency(RF)model is derived to evaluate the coverage quality,considering both Line of Sight(LOS)and Non-Line of Sight(NLOS)down-link coverage probabilities for ground *** is assumed that each drone is equipped with a directional antenna to optimize coverage in a given *** simulations are conducted to assess the effectiveness of the proposed *** demonstrate that the proposed method achieves maximum coverage with minimum transmission ***,a comparison is made against Collaborative Visual Area Coverage Approach(CVACA),and a game-based approach in terms of coverage quality and convergence *** simulation results reveal that our approach outperforms both CVACA and the gamebased schemes in terms of coverage an

关键词： IoD line of sight optimal deployment IPSO RF model

Interfacial/bulk synergetic effects accelerating charge transferring for advanced lithium-ion capacitors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第6期35卷 168-175页

作者： Chang Liu Zirui Song Xinglan Deng Shihong Xu Renji Zheng Wentao Deng Hongshuai Hou Guoqiang Zou Xiaobo Ji School of Chemistry and Chemical engineering Hunan Institute of EngineeringXiangtan 411104China College of Chemistry and Chemical engineering Central South UniversityChangsha 410083China Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-Containing Mineral Resources School of Minerals Processing and BioengineeringCentral South UniversityChangsha 410083China

The exploration of advanced materials through rational structure/phase design is the key to develop highperformance lithium-ion capacitors(LICs).However,high complexity of material preparation and difficulty in quantity production largely hinder the further ***,Cu_(5)FeS_(4-x)/C(CFS@C)heterojunction with rich sulfur vacancies has successfully achieved from natural bornite,presenting low costeffective and bulk-production *** functional theory(DFT)calculations indicate that rich vacancies in bulk phase can decrease band gap of bornite and thus improve its intrinsic electron conductivity,as well as the heterojunction spontaneously evokes a built-in electric field between its interfacial region,largely reducing the migration barrier from 1.27 e V to 0.75 e *** from these merits,the CFS@C electrodes deliver outperformed lithium storage performance,e.g.,high reversible capacity(822.4m Ah/g at 0.1 A/g),excellent cycling stability(up to 820 cycles at 2 A/g and 540 cycles at 5 A/g with respective capacity retention of over or nearly 100%).With CFS@C as anode and porous carbon nanosheets(PCS)as cathode,the assembled CFS@C//PCS LIC full cells exhibit high energy/power density characteristics of 139.2 Wh/kg at 2500 W/*** work is expected to offer significant insights into structure modifications/devising toward natural minerals for advanced energy-storage systems.

关键词： Bulk/interfacial modification Heterostructure Sulfur vacancies Lithium ion capacitors Capacitors

Magnesium-containing pellet regulating blast furnace ferrous burden interaction:softening-melting behavior and mechanism

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第7期31卷 1623-1635页

作者： Li-ming Ma Jian-liang Zhang Yao-zu Wang Xiao-yong Ma Gui-lin Wang Zhuo Li Hui-qing Jiang Zheng-jian Liu School of metallurgical and Ecological engineering University of Science and Technology BeijingBeijing 100083China School of Intelligence Science and Technology University of Science and Technology BeijingBeijing 100083China Lingyuan Iron and Steel Group Co. Lingyuan 122500LiaoningChina

MgO participates in all stages of sintering,pelletizing,and blast furnace ironmaking,and synergistically optimizing the distribution of MgO in ferrous burden can effectively enhance the interaction within the ferrous burdens and optimize the softening-melting properties of the mixed ***-containing pellets mixed with low-MgO sinter or mixed with high-MgO sinter in the blast furnace ferrous burden structure have opposite softening-melting performance *** the structure of the ferrous burden is magnesium-containing pellets mixed with low-MgO sinter,the magnesium-containing pellets can enhance the interaction of the ferrous burden in the process of softening-melting,which can optimize the composition of the slag phase and improve the slag *** the structure of the ferrous burden is magnesium-containing pellets mixed with high-MgO sinter,the magnesium-containing pellets weaken the interaction of the ferrous burden in the process of softening-melting,increase the content of the high melting point solid-phase particles in the slag,lead to an increase in the viscosity of the slag and difficult separation of the slag and iron,and decrease the permeability of the charge ***,to ensure good permeability of the mixed burden,the following measures are suggested:optimizing the MgO distribution of the ferrous burden,reducing the MgO content of the sinter to 1.96 wt.%,increasing the MgO content of the pellets to 1.03-1.30 wt.%,controlling the MgO/Al_(2)O_(3) ratio of the mixed burden within 1.15-1.32,narrowing the position of the cohesive zone,and maintaining an S value(permeability index)of approximately 150 kPa℃.

关键词： Ironmaking Ferrous burden Softening-melting property Interaction Permeability Slag

Effect of heat treatment on microstructural evolution,mechanical properties and tribological properties of H13 steel prepared using selective laser melting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第5期31卷 1246-1259页

作者： Li-xiong Han Yan Wang Shi-feng Liu Zhao-hui Zhang Wei Liu Xin Yang Dang-shen Ma Jian Zhou Ying-kang Wei College of metallurgical engineering Xi’an University of Architecture and TechnologyXi’an710055ShaanxiChina Zhejiang University City College Hangzhou310015ZhejiangChina China Iron and Steel Research Institute Group Co. Ltd.Beijing100081China

H13 tool steel was successfully prepared by selective laser melting(SLM)*** effects of heat treatment on the microstructure,mechanical properties,and tribological properties of SLMed H13 steel were *** heat treatment process involved a solution treatment and a double aging treatment of the deposited H13 tool steel prepared by *** aim is to optimize the microstructure and mechanical properties of SLMed H13 *** to the rapid heating and cooling effects of SLM,carbide precipitation in the deposited H13 steel was not uniform and residual stresses were *** purpose of the solution treatment is to dissolve the solution at a high temperature to eliminate the residual stresses and defects introduced by the SLM-forming *** solution treatment and first aging treatment produced the precipitation of small carbides at the grain boundaries and inside the crystals,which increased the hardness of SLMed H13 *** hardness increased from 538±4.0 HV of the as-deposited sample to 548±5.8 HV of samples after the first aging ***,the ultimate tensile strength and the elongation at break decreased from 1882 MPa and 11.5%in the as-deposited sample to 1697 MPa and 7.9%in those after the first aging treatment,***,the friction coefficient and wear rate in the as-deposited sample decreased from 0.5160 and 2.36×10^(–6)mm^(−3)N^(−1)m^(−1)to 0.4244 and 1.04×10^(–6)mm^(−3)N^(−1)m^(−1),***,the distribution of carbides inside the crystals was not *** second aging treatment adjusted the morphology of carbide precipitation and made it more uniform,but the precipitation of carbides grew and settled at the bottom of the grain *** hardness decreased to 533±6.7 HV compared with that with the first aging treatment,but the ultimate tensile strength and plasticity reached a balance(1807 MPa,14.05%).Accordingly,the friction coefficient and wear rate also showed a stable and decreasin

关键词： Selective laser melting H13 steel Solution aging Double aging Friction and wear Retained austenite