Role of iron ore in enhancing gasification of iron coke:Structural evolution,influence mechanism and kinetic analysis

The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was investigated.Furthermore,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method.The findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and interconnect.This provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron coke.Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke.The metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon atoms.The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure.Moreover,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.

Microdynamic mechanical properties and fracture evolution mechanism of monzogabbro with a true triaxial multilevel disturbance method

The far-field microdynamic disturbance caused by the excavation of deep mineral resources and underground engineering can induce surrounding rock damage in high-stress conditions and even lead to disasters.However,the mechanical properties and damage/fracture evolution mechanisms of deep rock induced by microdynamic disturbance under three-dimensional stress states are unclear.Therefore,a true triaxial multilevel disturbance test method is proposed,which can completely simulate natural geostress,excavation stress redistribution(such as stress unloading,concentration and rotation),and subsequently the microdynamic disturbance triggering damaged rock failure.Based on a dynamic true triaxial test platform,true triaxial microdynamic disturbance tests under different frequency and amplitudes were carried out on monzogabbro.The results show that increasing amplitude or decreasing frequency diminishes the failure strength of monzogabbro.Deformation modulus gradually decreases during disturbance failure.As frequency and amplitude increase,the degradation rate of deformation modulus decreases slightly,disturbance dissipated energy increases significantly,and disturbance deformation anisotropy strengthens obviously.A damage model has been proposed to quantitatively characterize the disturbance-induced damage evolution at different frequency and amplitude under true triaxial stress.Before disturbance failure,the micro-tensile crack mechanism is dominant,and the micro-shear crack mechanism increases significantly at failure.With the increase of amplitude and frequency,the micro-shear crack mechanism increases.When approaching disturbance failure,the acoustic emission fractal dimension changes from a stable value to local large oscillation,and finally increases sharply to a high value at failure.Finally,the disturbance-induced failure mechanism of surrounding rock in deep engineering is clearly elucidated.

Formation and Evolution Mechanism of High-quality Reservoirs in the Lacustrine Hyperpycnal System:The 2nd Member of the Lower Jurassic Sangonghe Formation,Qiudong Subsag,Turpan-Hami Basin,NW China

Hyperpycnal deposits has gradually emerged as a current research hotspot,with a special focus on lacustrine hyperpycnal deposits.However,our understanding of the formation mechanism and distribution of high-quality reservoirs in hyperpycnal deposits remains insufficient.In this study,the formation mechanism and distribution of high-quality reservoirs in the second member of the Sangonghe Formation are studied through sedimentology,petrology,and geochemistry,and 10 types of lithofacies were identified in the depositional sequences of the hyperpycnal flow.These can be summarized as gravelly bed to suspended load lithofacies association(GBS),gravelly reverse to normal compound-graded(GNR),coarse-grained sandy suspended load(CSS),and fine-grained sandy suspended load(FSS)lithofacies associations.The hyperpycnal system can be divided into four individual units:restricted channel,unrestricted channel,lobe,and levee.The reservoir quality varies with lithofacies.Gravelly bed load lithofacies has coarse grain sizes,high content of rigid minerals,and soluble components,such as magmatic rock fragments.Therefore,the gravelly bed load lithofacies reservoir has developed dissolution pores and well-preserved pore throats.Its reservoir quality is good.GBS and GNR are the main lithofacies associations in the restricted channel,where type I and type II reservoirs developed.The unrestricted channel is dominated by the CSS lithofacies association,with type III reservoirs developed.The lobe is dominated by the CSS and FSS lithofacies associations,with type III and type IV reservoirs developed.High-quality reservoirs mainly develop in the restricted and unrestricted channels,whereas reservoirs in the lobe have poor quality.The levees are dominated by siltstone and gray mudstone and are generally nonreservoirs.

Exploring the Cation Regulation Mechanism for Interfacial Water Involved in the Hydrogen Evolution Reaction by In Situ Raman Spectroscopy

Interfacial water molecules are the most important participants in the hydrogen evolution reaction(HER).Hence,understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism.Unfortunately,investigating interfacial water is extremely challenging owing to the interference caused by bulk water molecules and complexity of the interfacial environment.Here,the behaviors of interfacial water in different cationic electrolytes on Pd surfaces were investigated by the electrochemistry,in situ core-shell nanostructure enhanced Raman spectroscopy and theoretical simulation techniques.Direct spectral evidence reveals a red shift in the frequency and a decrease in the intensity of interfacial water as the potential is shifted in the positively direction.When comparing the different cation electrolyte systems at a given potential,the frequency of the interfacial water peak increases in the specified order:Li+<Na^(+)<K^(+)<Ca^(2+)<Sr^(2+).The structure of interfacial water was optimized by adjusting the radius,valence,and concentration of cation to form the two-H down structure.This unique interfacial water structure will improve the charge transfer efficiency between the water and electrode further enhancing the HER performance.Therefore,local cation tuning strategies can be used to improve the HER performance by optimizing the interfacial water structure.

Evolution mechanism and treatment timing of penetrating fissures

The Inner Mongolia mining area in western China are characterized by the development of numerous penetrating fissures,resulting in severe land damage.It is significant to reveal the underlying evolution mechanism and identify treatment timing for restoring the ecological environment.The Guanbanwusu mining subsidence area in Inner Mongolia,China was selected as the research case for this study.The evolution mechanism of different penetrating fissures was revealed by field measurement,physical simulation and theoretical analysis.The treatment timing prediction model for the mining subsidence area was established based on the enhanced Weibull time function.The results show that the ground fissures are mainly step-type and collapse-type fissures.The breaking form of overlying strata determines their vertical opening and horizontal dislocation.The high mining intensity in the western mining area results in a shortened period of dynamic fissure expansion and reduced closure degree.The damage extent of the overlying strata exhibits zoning characteristics both vertically and horizontally.The relative standard deviation of the prediction model is only 3.7%.Concurrently,the prediction model is employed to determine the optimal timing for treatment in the study area,estimated to be 259 days.Subsequently,once this threshold is reached,the study area undergoes treatment and restoration of its e cological environment.This study addresses the knowledge gap in this field by highlighting the interconnectedness between rock strata structure and evolution mechanism of penetrating fissures,thereby providing a method for determining the treatment timing in mining subsidence areas.

Microstructural evolution and deformation mechanisms of superplastic aluminium alloys:A review

Aluminium alloy is one of the earliest and most widely used superplastic materials.The objective of this work is to review the scientific advances in superplastic Al alloys.Particularly,the emphasis is placed on the microstructural evolution and deformation mechanisms of Al alloys during superplastic deformation.The evolution of grain structure,texture,secondary phase,and cavities during superplastic flow in typical superplastic Al alloys is discussed in detail.The quantitative evaluation of different deformation mechanisms based on the focus ion beam(FIB)-assisted surface study provides new insights into the superplasticity of Al alloys.The main features,such as grain boundary sliding,intragranular dislocation slip,and diffusion creep can be observed intuitively and analyzed quantitatively.This study provides some reference for the research of superplastic deformation mechanism and the development of superplastic Al alloys.

Inner Ear of Miocene Fossil Ape Gives Clues to Evolution of Bipedalism

Anew study of a 7–8-million-year-old extinct fossil ape from China called Lufengpithecus offers new insights into the evolution of human bipedalism.The study,published in The Innovation,was conducted by a team from the Institute of Vertebrate Paleontology and Paleoanthropology(IVPP)of the Chinese Academy of Sciences,the Yunnan Institute of Cultural Relics and Archaeology(YICRA),and New York University(NYU).

Highly mass activity electrocatalysts with ultralow Pt loading on carbon black for hydrogen evolution reaction

Pt-based nanocatalysts offer excellent prospects for various industries.However,the low loading of Pt with excellent performance for efficient and stable nanocatalysts still presents a considerable challenge.In this study,nanocatalysts with ultralow Pt content,excellent performance,and carbon black as support were prepared through in-situ synthesis.These~2-nm particles uniformly and stably dispersed on carbon black because of the strong s-p-d orbital hybridizations between carbon black and Pt,which suppressed the agglomeration of Pt ions.This unique structure is beneficial for the hydrogen evolution reaction.The catalysts exhibited remarkable catalytic activity for hydrogen evolution reaction,exhibiting a potential of 100 mV at 100 mA·cm^(-2),which is comparable to those of commercial Pt/C catalysts.Mass activity(1.61 A/mg)was four times that of a commercial Pt/C catalyst(0.37 A/mg).The ultralow Pt loading(6.84wt%)paves the way for the development of next-generation electrocatalysts.

Catalyst–Support Interaction in Polyaniline‑Supported Ni_(3)Fe Oxide to Boost Oxygen Evolution Activities for Rechargeable Zn‑Air Batteries

Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.

Low‑Temperature Oxidation Induced Phase Evolution with Gradient Magnetic Heterointerfaces for Superior Electromagnetic Wave Absorption

Gradient magnetic heterointerfaces have injected infinite vitality in optimizing impedance matching,adjusting dielectric/magnetic resonance and promoting electromagnetic(EM)wave absorption,but still exist a significant challenging in regulating local phase evolution.Herein,accordion-shaped Co/Co_(3)O_(4)@N-doped carbon nanosheets(Co/Co_(3)O_(4)@NC)with gradient magnetic heterointerfaces have been fabricated via the cooperative high-temperature carbonization and lowtemperature oxidation process.The results indicate that the surface epitaxial growth of crystal Co_(3)O_(4) domains on local Co nanoparticles realizes the adjustment of magnetic-heteroatomic components,which are beneficial for optimizing impedance matching and interfacial polarization.Moreover,gradient magnetic heterointerfaces simultaneously realize magnetic coupling,and long-range magnetic diffraction.Specifically,the synthesized Co/Co_(3)O_(4)@NC absorbents display the strong electromagnetic wave attenuation capability of−53.5 dB at a thickness of 3.0 mm with an effective absorption bandwidth of 5.36 GHz,both are superior to those of single magnetic domains embedded in carbon matrix.This design concept provides us an inspiration in optimizing interfacial polarization,regulating magnetic coupling and promoting electromagnetic wave absorption.

Experimental Observing Damage Evolution in Cement Pastes Exposed to External Sulfate Attack by in situ X-ray Computed Tomography

The paper presents experimental investigation results of crack pattern change in cement pastes caused by external sulfate attack(ESA).To visualize the formation and development of cracks in cement pastes under ESA,an X-ray computed tomography(X-ray CT)was used,i e,the tomography system of Zeiss Xradia 510 versa.The results indicate that X-CT can monitor the development process and distribution characteristics of the internal cracks of cement pastes under ESA with attack time.In addition,the C3A content in the cement significantly affects the damage mode of cement paste specimens during sulfate erosion.The damage of ordinary Portland cement(OPC)pastes subjected to sulfate attack with high C3A content are severe,while the damage of sulfate resistant Portland cement(SRPC)pastes is much smaller than that of OPC pastes.Furthermore,a quadratic function describes the correlation between the crack volume fraction and development depth for two cement pastes immermed in sulfate solution.

Boosting Oxygen Evolution Reaction Performance on NiFe‑Based Catalysts Through d‑Orbital Hybridization

Anion-exchange membrane water electrolyzers(AEMWEs)for green hydrogen production have received intensive attention due to their feasibility of using earth-abundant NiFe-based catalysts.By introducing a third metal into NiFe-based catalysts to construct asymmetrical M-NiFe units,the d-orbital and electronic structures can be adjusted,which is an important strategy to achieve sufficient oxygen evolution reaction(OER)performance in AEMWEs.Herein,the ternary NiFeM(M:La,Mo)catalysts featured with distinct M-NiFe units and varying d-orbitals are reported in this work.Experimental and theoretical calculation results reveal that the doping of La leads to optimized hybridization between d orbital in NiFeM and 2p in oxygen,resulting in enhanced adsorption strength of oxygen intermediates,and reduced rate-determining step energy barrier,which is responsible for the enhanced OER performance.More critically,the obtained NiFeLa catalyst only requires 1.58 V to reach 1 A cm^(−2) in an anion exchange membrane electrolyzer and demonstrates excellent long-term stability of up to 600 h.

基于DEMATEL-ISM模型的国内现代木结构建筑发展制约因素分析

由于具有低碳、抗震、环保等优点,现代木结构受到人们的广泛关注。然而,在实践中,认知不足、适用范围受限,以及标准规范不健全等因素制约了其发展。为此,文章通过文献分析、专家访谈和问卷调查等方法,对国内现代木结构建筑发展的制约因素进行了挖掘与分析,总结了21个制约因素。通过DEMATEL-ISM模型构建的国内现代木结构建筑发展的制约因素递阶结构模型表明,缺乏适用的标准规范和现行标准规范的约束是阻碍其在国内发展的根本因素。鉴于此,文章提出了一系列对策建议,旨在充实现代木结构建筑的相关理论研究,为其发展提供理论指导。

Deformation mechanism of cold ring rolling in view of texture evolution predicted by a newly proposed polycrystal plasticity model

An explicit polycrystal plasticity model was proposed to investigate the deformation mechanism of cold ring rolling in view of texture evolution. The model was created by deducing a set of linear incremental controlling equations within the framework of crystal plasticity theory. It was directly solved by a linear algorithm within a two-level procedure so that its efficiency and stability were guaranteed. A subroutine VUMAT for ABAQUS/Explicit was developed to combine this model with the 3D FE model of cold ring rolling. Results indicate that the model is reliable in predictions of stress-strain response and texture evolution in the dynamic complicated forming process; the shear strain in RD of the ring is the critical deformation mode according to the sharp Goss component （{110}？100？） of deformed ring; texture and crystallographic structure of the ring blank do not affect texture type of the deformed ring;texture evolves rapidly at the later stage of rolling, which results in a dramatically increasing deformation of the ring.

Evolution mechanism of demand for comprehensive transportation system based on metabolic ecology

The metabolic evolution model of transportation demand for comprehensive transportation systems is put forward on the basis of a metabolic theory of ecology. In the model, the growth rates or changing rates of transportation volumes for the various transportation modes of a city are determined not only by the GDP per capita which reflects the size of the city itself, but also by the relationship of competition and cooperation among transportation modes. The results of empirical analysis for Chinese cities show that the allometric growth exponent in the equation for the variation rate of passenger demand volume on rail is greater than the predicted value of 1/4 in metabolic ecology, whereas the allometric growth relationship is not so evident in the equation for the variation rate of passenger demand volume on road. The changing rate of road transportation is thus mainly affected by the relationship of competition and cooperation among transportation modes for Chinese cities.

基于DEMATEL-ISM的公共设施可持续设计提升策略研究

目的 为探索可持续设计需求在公共设施设计中的重要性问题,准确全面地推进公共设施的可持续设计,构建覆盖公共设施生命全周期的多指标设计体系模型,对设计阶段前期的因素重要性需求及相关性进行评估。从而支持在后续的公共设施设计过程中的可持续设计评估。方法 以可持续设计的环境价值、经济价值和社会价值为目标层,对美景度、环保度等9个影响因素进行分析,获取公共设施在可持续设计方面的各种影响因素,构建研究体系。在此基础上,提出运用DEMATEL-ISM组合模型探究各制约因素间的复杂影响关系,利用排序和重要性结果,寻找关键要素,绘制层级关系示意图,使各种因素之间的关系更加条理化、层次化。根据计算结果提出有助于在设计阶段提高公共设施设计可持续的策略及建议。结果 研究表明,在公共设施的可持续设计中,实用度和可控度的中心度最高,为重要的影响因素。公共设施可持续设计需要以提高美景度及和谐度为改善基础,实用度、可控度和体验度为调节因素,最终通过控制环保度、耐久度等因素,保障公共设施设计的可持续运行。结论 基于DEMATEL-ISM可以直观清晰地展现公共设施可持续设计影响因素之间的相互关系。通过对模型信息的理性分析,能够促使后期设计方案在公共设施生命全周期的各个维度上具有可持续性,并在理论层面为设计环节的决策提供参考依据。

家庭农场数字农业技术采纳作用机制——基于ISM-MICMAC模型分析

为探究家庭农场数字农业技术采纳作用机制,通过构建技术采纳影响因素体系,利用ISM-MICMAC模型得出各层次因素、驱动力-依赖性矩阵。ISM层次模型表明,技术安全性感知是直接表层因素,社会网络、设备操作能力、家庭收入、耕地面积、组织化程度、土地细碎化程度、是否参加培训、技术有用性感知和技术易用性感知是中层间接因素,家庭农场主的政治身份、受教育程度、年龄、家庭劳动力人数、居住地理位置、政府宣传引导、政府经济补贴和基础设施是深层本质因素,对技术采纳起决定性作用;驱动力-依赖性矩阵表明,家庭农场主政治身份、受教育程度属高驱动力、低依赖性独立因素。据此提出完善数字基础设施、强化宣传推广、开展教育培训和增加政策扶持等对策。

基于集成DEMATEL-ISM的民航飞行安全风险影响因素研究

航空安全是民航发展的生命线,飞行安全风险研究是飞行安全分析的重要内容,飞行安全风险影响因素的研究是飞行安全风险研究的重要基础。为研究民航飞行安全风险影响因素,在构建飞行安全风险评价指标体系的基础上,采用决策式实验分析法和解释结构模型联合法(decision-making trial and evaluation laboratory-interpretative structural modeling method,DEMATEL-ISM)的算法构建飞行安全风险影响因素模型,对因素的属性、重要度、作用机理等进行深入分析,建立系统性的多级递阶结构模型。最后通过算例编程仿真实现,对结果深入分析与研究,探讨其实际应用价值,证明该方法的可行性和有效性,该方法可以为飞行安全风险管理提供决策帮助和理论指导,有助于提升飞行安全管理水平。

基于DEMATEL-ISM模型的地铁火灾疏散影响因素研究

为减少地铁火灾事故对人员及财产安全的威胁,提升地铁火灾疏散安全性,对地铁火灾疏散影响因素进行系统性研究。在构建地铁火灾疏散影响因素指标体系的基础上,将决策实验室分析法(DEMATEL)与解释结构模型(ISM)联合,用于研究各因素对地铁火灾疏散系统的重要程度,并对各因素间的逻辑结构进行梳理分析。结果表明,恐慌心理和火灾产物分别为影响地铁火灾疏散系统安全性的关键性直接因素和根本因素,24个地铁火灾疏散影响因素可划分为3层5阶的递阶结构。此研究有助于科学认识地铁火灾疏散系统,对提高实际疏散安全性具有参考价值。

基于DEMATEL-ISM的水利工程EPC项目价值增值机理研究

采用设计-采购-施工(engineering-procurement-construction,EPC)总承包模式的水利工程项目日益增多,研究其价值增值机理有利于总承包方做好项目的价值管理。从水利工程EPC项目的价值链分析入手,基于文献和专家访谈得到23个价值增值影响因素。采用问卷调查方式得到各因素间的影响程度评分,用决策实验和评估实验(decision-making trial and evaluation laboratory,DEMATEL)法计算了各因素的中心度和原因度,结合解释结构模型(interpretative structural modeling,ISM)对数据进行分析,将价值增值因素划分为6类,构建了水利工程EPC项目价值增值的递阶模型,探究和揭示了项目价值增值的路径和机理。研究结果对水利工程EPC总承包方制订管理策略有一定启示作用。