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 micro...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%.展开更多
Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler ...Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler metals is ever-increasing.It is of great significance to investigate the optimized composition design methods and to establish systematic design guidelines for brazing filler metals.This study elucidated the fundamental rules for the composition design of brazing filler metals from a three-dimensional perspective encompassing the basic properties of applied brazing filler metals,formability and processability,and overall cost.The basic properties of brazing filler metals refer to their mechanical properties,physicochemical properties,electromagnetic properties,corrosion resistance,and the wettability and fluidity during brazing.The formability and processability of brazing filler metals include the processes of smelting and casting,extrusion,rolling,drawing and ring-making,as well as the processes of granulation,powder production,and the molding of amorphous and microcrystalline structures.The cost of brazing filler metals corresponds to the sum of materials value and manufacturing cost.Improving the comprehensive properties of brazing filler metals requires a comprehensive and systematic consideration of design indicators.Highlighting the unique characteristics of brazing filler metals should focus on relevant technical indicators.Binary or ternary eutectic structures can effectively enhance the flow spreading ability of brazing filler metals,and solid solution structures contribute to the formability.By employing the proposed design guidelines,typical Ag based,Cu based,Zn based brazing filler metals,and Sn based solders were designed and successfully applied in major scientific and engineering projects.展开更多
Subtropical evergreen broad-leaved trees are usually vulnerable to freezing stress,while hexaploid wild Camellia oleifera shows strong freezing tolerance.As a valuable genetic resource of woody oil crop C.oleifera,wil...Subtropical evergreen broad-leaved trees are usually vulnerable to freezing stress,while hexaploid wild Camellia oleifera shows strong freezing tolerance.As a valuable genetic resource of woody oil crop C.oleifera,wild C.oleifera can serve as a case for studying the molecular bases of adaptive evolution to freezing stress.Here,47 wild C.oleifera from 11 natural distribution sites in China and 4 relative species of C.oleifera were selected for genome sequencing.“Min Temperature of Coldest Month”(BIO6)had the highest comprehensive contribution to wild C.oleifera distribution.The population genetic structure of wild C.oleifera could be divided into two groups:in cold winter(BIO6≤0℃)and warm winter(BIO6>0℃)areas.Wild C.oleifera in cold winter areas might have experienced stronger selection pressures and population bottlenecks with lower N_(e) than those in warm winter areas.155 singlenucleotide polymorphisms(SNPs)were significantly correlated with the key bioclimatic variables(106 SNPs significantly correlated with BIO6).Twenty key SNPs and 15 key copy number variation regions(CNVRs)were found with genotype differentiation>50%between the two groups of wild C.oleifera.Key SNPs in cis-regulatory elements might affect the expression of key genes associated with freezing tolerance,and they were also found within a CNVR suggesting interactions between them.Some key CNVRs in the exon regions were closely related to the differentially expressed genes under freezing stress.The findings suggest that rich SNPs and CNVRs in polyploid trees may contribute to the adaptive evolution to freezing stress.展开更多
The microstructure evolution and deformation mechanism of a DZ125 superalloy during high-temperature creep were studied by means of microstructure observation and creep-property tests.The results show that at the init...The microstructure evolution and deformation mechanism of a DZ125 superalloy during high-temperature creep were studied by means of microstructure observation and creep-property tests.The results show that at the initial stage of high-temperature creep,two sets of dislocations with different Burgers vectors move and meet inγmatrix channels,and react to form a quadrilateral dislocation network.Andγ′phases with raft-like microstructure are generated after the formation of dislocation networks.As creep progresses,the quadrilateral dislocation network is gradually transformed into hexagonal and quadrilateral dislocation networks.During steady stage of creep,the superalloy undergoes deformation with the mechanism that a great number of dislocations slip and climb in the matrix across the raft-likeγ′phases.At the later stage of creep,the raft-likeγ′phases are sheared by dislocations at the breakage of dislocation networks,and then alternate slip occurs,which distorts and breaks the raft-likeγ′/γphases,resulting in the accumulation of micropores at the raft-likeγ′/γinterfaces and the formation of microcracks.As creep continues,the microcracks continue to expand until creep fracture occurs,which is the damage and fracture mechanism of the alloy at the later stage of creep at high temperature.展开更多
This paper is about the transformation process of theoretical frameworks used in educational research on teaching evolution. To this end, some authors' claims, findings and suggestions offered via particular studi...This paper is about the transformation process of theoretical frameworks used in educational research on teaching evolution. To this end, some authors' claims, findings and suggestions offered via particular studies are evaluated. While the evaluated authors have represented secularism as a barrier to teaching evolution in the United States, they have also offered pedagogically theistic or agnostic evolution as the best choice for the reconciliation of religion and evolution. This paper is particularly concerned with one of the explanatory theoretical frameworks—religious cultural competence in evolution education(ReCCEE), which is derived from the cultural competence framework—although others are visited as well. Even though the schools or authors who have applied ReCCEE do not directly reference constructivism, their studies are built upon constructivist pedagogy and epistemological idealism. They often have problematic issues such as obscurantism, ad hominem attacks, cherry-picking and an ill-formed appeal to authority. Besides, these papers present biased or uncritical views and ill-informed definitions of some terms, such as secularism and agnosticism.展开更多
The study of the oxygen evolution reaction(OER)mechanism is vital for advancing our understanding of this pivotal energy conversion process.This review synthesizes recent advancements in OER mechanism,emphasizing the ...The study of the oxygen evolution reaction(OER)mechanism is vital for advancing our understanding of this pivotal energy conversion process.This review synthesizes recent advancements in OER mechanism,emphasizing the intricate relationship between catalytic mechanisms and catalyst design.This review discusses the connotation and cutting-edge progress of traditional mechanisms such as adsorbate evolution mechanism(AEM)and lattice oxygen mechanism(LOM)as well as emerging pathways including oxide path mechanism(OPM),oxo-oxo coupling mechanism(OCM),and intramolecular oxygen coupling mechanism(IMOC)etc.Innovative research progress on the coexistence and transformation of multiple mechanisms is highlighted,and the intrinsic factors that influence these dynamic processes are summarized.Advanced characterization techniques and theoretical modeling are underscored as indispensable tools for revealing these complex interactions.This review provides guiding principles for mechanism-based catalyst design.Finally,in view of the multidimensional challenges currently faced by OER mechanisms,prospects for future research are given to bridge the gap between mechanism innovation and experimental verification and application.This comprehensive review provides valuable perspectives for advancing clean energy technologies and achieving sustainable development.展开更多
To accurately investigate the evolution characteristics and generation mechanism of retained oil,the study analyzed organic-rich lacustrine shale samples from the Paleogene Kongdian Formation in Cangdong Sag,Bohai Bay...To accurately investigate the evolution characteristics and generation mechanism of retained oil,the study analyzed organic-rich lacustrine shale samples from the Paleogene Kongdian Formation in Cangdong Sag,Bohai Bay Basin.This analysis involves Rock-Eval pyrolysis,pyrolysis simulation experiments,Gas Chromatograph Mass Spectrometer(GC-MS),and reactive molecular dynamics simulations(ReaxFF).The results revealed the retained oil primarily consisted of n-alkanes with carbon numbers ranging from C14 to C36.The generation of retained oil occurred through three stages.A slow growth stage of production rate was observed before reaching the peak of oil production in Stage Ⅰ.Stage Ⅱ involved a rapid increase in oil retention,with C12-C17 and C24-C32 serving as the primary components,increasing continuously during the pyrolysis process.The generation process involved the cleavage of weak bonds,including bridging bonds(hydroxyl,oxy,peroxy,imino,amino,and nitro),ether bonds,and acid amides in the first stage(Ro=0.50%-0.75%).The carbon chains in aromatic ring structures with heteroatomic functional groups breaks in the second stage(R_(o)=0.75%-1.20%).In the third stage(R_(o)=1.20%-2.50%),the ring structures underwent ring-opening reactions to synthesize iso-short-chain olefins and radicals,while further breakdown of aliphatic chains occurred.By coupling pyrolysis simu-lation experiments and molecular simulation technology,the evolution characteristics and bond breaking mechanism of retained oil in three stages were revealed,providing a reference for the for-mation and evolution mechanism of retained oil.展开更多
Amid ongoing global environmental change and the critical pursuit of sustainable development,human-environment systems are exhibiting increasingly complex dynamic evolutions and spatial relationships,underscoring an u...Amid ongoing global environmental change and the critical pursuit of sustainable development,human-environment systems are exhibiting increasingly complex dynamic evolutions and spatial relationships,underscoring an urgent need for innovative research frameworks.Integrated geography synthesizes physical geography,human geography,and geographic information science,providing key frameworks for understanding complex human-environment systems.This editorial proposes an emerging research framework for integrated geography—“Composite driving-System evolution-Coupling mechanism-Synergistic regulation(CSCS)”—based on key issues such as climate change,biodiversity loss,resource scarcity,and social-ecological interactions,which have been highlighted in both recent critical literature on human-environment systems and UN assessment reports.The framework starts with diverse composite driving forces,extends to the evolution of human-environment system structures,processes,and functions that these drivers induce,explores couplings within human-environment systems,and calls for regulation aimed at sustainable development in synergies.Major research frontiers include understanding the cascading“evolution-coupling”effects of shocks;measuring system resilience,thresholds,and safe and just operating space boundaries;clarifying linkage mechanisms across scales;and achieving synergistic outcomes for multi-objective sustainability.This framework will help promote the interdisciplinary integration and development of integrated geography,and provide geographical solutions for the global sustainable development agenda.展开更多
The Bijigou intrusion is one of the largest and most well-differentiated Fe–Ti oxide-bearing layered intrusions in the Hannan massif located in the northwestern margin of the Yangtze Block,South China.Besides the min...The Bijigou intrusion is one of the largest and most well-differentiated Fe–Ti oxide-bearing layered intrusions in the Hannan massif located in the northwestern margin of the Yangtze Block,South China.Besides the mineralization-related mafic-ultramafic rocks,the intermediate-acid intrusive rocks are also exposed in the mining area,which is of great significance for the understanding the Neoproterozoic tectonic evolution of the Yangtze Block,but studies on these intermediate-acid rocks are scarce.The Bijigou mafic-ultramafic layered intrusion is surrounded by granite and cut by syenite veins.Here,we report new zircon U-Pb ages,Lu-Hf isotope composition and bulk rock geochemical data of the Bijigou syenite vein and wall-rock granite in the northwestern margin of the Yangtze Block.Laser ablation inductively coupled plasma mass spectrometry(LAICP-MS)zircon U-Pb dating results show that the Bijigou syenite vein and wall-rock granite formed at 770±3.5 Ma(MSWD=0.17,n=28)and 810±4 Ma(MSWD=0.84,n=26),respectively.The zirconεHf(t)values of the syenite veins range from+1.52 to+5.33(average of+3.05),combined with its high potassium contents,negative Nb–Ta anomalies and positive Pb anomalies,suggesting that they may have originated from mantle-derived basaltic magma,which was modified by materials from subducting oceanic slab.The zirconεHf(t)and T_(DM2)ages of the wall-rock granite range from+0.71 to+5.71(average+3.06)and 1344 to 1659 Ma(average 1519 Ma),respectively,indicating that the granite was produced by partial melting of juvenile crust.The geochemical characteristics of the Bijigou syenite and granite indicate that they were formed in a continental margin arc setting.Thus,combined with previous studies,it suggests that there was a major subduction system along the northwestern margin of the Yangtze Block during 824-720 Ma,and the magmatism in the Hannan massif was divided into two episodes:(1)early magmatism(824-790 Ma),such as the Bijigou,Hongmiaozhen and Huangguanzhen granitoids,was derived from partial melting of the juvenile or pre-existing crust in a continental arc setting;(2)later magmatism(789-718 Ma),including Bijigou syenite,Wudumen,Erliba and Zushidian granitoids,formed in a subduction-related back-arc extensional environment.The long-term subduction system along the northwestern margin of the Yangtze Block during 824-720 Ma suggests that the Yangtze Block was previously located at the periphery of the Rodinia supercontinent.展开更多
When performing tasks,unmanned clusters often face a variety of strategy choices.One of the key issues in unmanned cluster tasks is the method through which to design autonomous collaboration and cooperative evolution...When performing tasks,unmanned clusters often face a variety of strategy choices.One of the key issues in unmanned cluster tasks is the method through which to design autonomous collaboration and cooperative evolution mechanisms that allow for unmanned clusters to maximize their overall task effective-ness under the condition of strategic diversity.This paper ana-lyzes these task requirements from three perspectives:the diver-sity of the decision space,information network construction,and the autonomous collaboration mechanism.Then,this paper pro-poses a method for solving the problem of strategy selection diversity under two network structures.Next,this paper presents a Moran-rule-based evolution dynamics model for unmanned cluster strategies and a vision-driven-mechanism-based evolu-tion dynamics model for unmanned cluster strategy in the con-text of strategy selection diversity according to various unmanned cluster application scenarios.Finally,this paper pro-vides a simulation analysis of the effects of relevant parameters such as the payoff factor and cluster size on cooperative evolu-tion in autonomous cluster collaboration for the two types of models.On this basis,this paper presents advice for effectively addressing diverse choices in unmanned cluster tasks,thereby providing decision support for practical applications of unmanned cluster tasks.展开更多
Differential evolution(DE)algorithms are simple and efficient evolutionary algorithms that performwell in various optimization problems.Unfortunately,they inevitably stagnate when differential evolutionary algorithms ...Differential evolution(DE)algorithms are simple and efficient evolutionary algorithms that performwell in various optimization problems.Unfortunately,they inevitably stagnate when differential evolutionary algorithms are used to solve complex problems(e.g.,real-world artificial neural network(ANN)training problems).To resolve this issue,this paper proposes a framework based on an efficient elite centroid operator.It continuously monitors the current state of the population.Once stagnation is detected,two dedicated operators,centroid-based mutation(CM)and centroid-based crossover(CX),are executed to replace the classical mutation and binomial crossover operations in DE.CM and CX are centred on the elite centroid composed of multiple elite individuals,constituting a framework consisting of elitism centroid-based operations(CMX)to improve the performance of the individuals who fall into stagnation.In CM,elite centroid provide evolutionary direction for stagnant individuals,and in CX,elite plasmoids address the limitation that stagnant individuals can only obtain limited information about the population.The CMX framework is simple enough to easily incorporate into both classically well-known DEs with constant population sizes and state-of-the-art DEs with varying populations.Numerical experiments on benchmark functions show that the proposed CMX method can significantly enhance the classical DE algorithm and its advanced variants in solving the stagnation problem and improving performance.展开更多
Globalization has resulted in a notable rise in the flow of high-skilled talent from emerging countries to developed nations. Current research on transnational talent flow mainly focuses on the destination countries, ...Globalization has resulted in a notable rise in the flow of high-skilled talent from emerging countries to developed nations. Current research on transnational talent flow mainly focuses on the destination countries, with less attention given to the perspective of the sending countries, particularly lacking a dynamic discussion on its impact on technological evolution in the origin countries. Based on the OECD REGPAT database, this paper aims to explore how talent groups migrating to developed countries facilitate the return of knowledge and technology to emerging countries and achieve breakthroughs in their technological evolution paths, while further discussing the potential mechanisms involved. The findings of this paper are as follows:(1) The technological development of emerging countries is a path-dependent process, where countries often branch into new technologies related to their preexisting knowledge base. Consequently, knowledge feedback from high-skilled talents increases the likelihood of sending countries developing unrelated technologies.(2) The mobility of talents across borders fosters more international collaborations and citations for patents that are unrelated to the local knowledge base, thus enriching the technological paths of sending countries.(3) The mobility of high-skilled talents primarily affects complex technologies, which have significant economic effects that encourage imitation by other countries.However, the effect on novel technologies is less significant due to their strong geographical stickiness. In general, this paper addresses the gaps in existing research on talent outflow and the technological evolution of origin countries, providing empirical evidence for the positive role of transnational talent mobility in the technological catch-up of emerging nations.Besides, it offers recommendations for talent export, import, and innovation policy formulation in these countries.展开更多
The Longmenshan structural belt on the eastern edge of the Tibetan Plateau experienced the impactful Mw7.92008 Wenchuan Earthquake,causing a 350 km surface rupture.Traditional models attribute this to the Beichuan and...The Longmenshan structural belt on the eastern edge of the Tibetan Plateau experienced the impactful Mw7.92008 Wenchuan Earthquake,causing a 350 km surface rupture.Traditional models attribute this to the Beichuan and Pengguan faults,but our research reveals a complex fault system at the northern end,with inconsistencies in surface rupture,aftershock distribution,and focal mechanisms.We integrate shallow geology,active source seismic reflection,and magnetotelluric profiling to establish a deep structural model for the northern end of the Longmenshan structural belt.This area exhibits dominant reverse thrust nappe tectonics,and analyzing the tectonic evolution history provides insights into deformation propagation from the orogenic belt toward the Sichuan Basin.Focal mechanism analysis and relocated aftershock data reveals two distinct types of seismogenic structures in the northern end of the Longmenshan structural belt.In the middle to northern segments,the reverse fault type is attributed to reactivated pre-existing faults.Conversely,at the northern end,the strike-slip fault type originates from high-angle co-seismic rupture cutting through pre-existing reverse faults.This study enhances our understanding of fault complexity and seismic mechanisms in the northeastern Longmenshan structural belt,providing new insights into regional tectonics.展开更多
Data clustering is an essential technique for analyzing complex datasets and continues to be a central research topic in data analysis.Traditional clustering algorithms,such as K-means,are widely used due to their sim...Data clustering is an essential technique for analyzing complex datasets and continues to be a central research topic in data analysis.Traditional clustering algorithms,such as K-means,are widely used due to their simplicity and efficiency.This paper proposes a novel Spiral Mechanism-Optimized Phasmatodea Population Evolution Algorithm(SPPE)to improve clustering performance.The SPPE algorithm introduces several enhancements to the standard Phasmatodea Population Evolution(PPE)algorithm.Firstly,a Variable Neighborhood Search(VNS)factor is incorporated to strengthen the local search capability and foster population diversity.Secondly,a position update model,incorporating a spiral mechanism,is designed to improve the algorithm’s global exploration and convergence speed.Finally,a dynamic balancing factor,guided by fitness values,adjusts the search process to balance exploration and exploitation effectively.The performance of SPPE is first validated on CEC2013 benchmark functions,where it demonstrates excellent convergence speed and superior optimization results compared to several state-of-the-art metaheuristic algorithms.To further verify its practical applicability,SPPE is combined with the K-means algorithm for data clustering and tested on seven datasets.Experimental results show that SPPE-K-means improves clustering accuracy,reduces dependency on initialization,and outperforms other clustering approaches.This study highlights SPPE’s robustness and efficiency in solving both optimization and clustering challenges,making it a promising tool for complex data analysis tasks.展开更多
Coal and rock dynamic disasters are always major hidden dangers threatening mine safety production.Many researchers use cement concrete material as filling and energy-absorption materials.However,the current material ...Coal and rock dynamic disasters are always major hidden dangers threatening mine safety production.Many researchers use cement concrete material as filling and energy-absorption materials.However,the current material toughness is not sufficient to meet the requirements of mine disaster prevention.Based on this,in order to find the optimal-ratio material that combines strength and toughness,the synergistic mechanism of lithium slag(LS),ethylene-vinyl acetate(EVA)copolymer,and polyvinyl alcohol(PVA)fiber mixtures in improving the mechanical properties of cement concrete,as well as the mechanism of microscopic phase evolution,was analyzed through macroscopic experiments,mesoscopic characterization,microscopic analysis,theoretical calculations,and comprehensive evaluation.The stress-strain curves obtained from the uniaxial compressive strength tests of specimens with different admixtures and fibers were investigated,and the characteristics of different stages were analyzed.The mechanical properties of different admixtures and fiber-reinforced materials,including their advantages and disadvantages,were compared through weighted comprehensive evaluation.The entire process of material failure,ranging from pore compaction,crack initiation,crack propagation,specimen instability to crack penetration,was explained via macroscopic fracture morphology,and the mechanical mechanism of how different admixtures affect the mechanical properties of concrete materials was revealed.The microscopic mechanism and the phase-evolution process of how the admixture affects concrete properties were elucidated using X-ray diffraction(XRD),hydration reaction theory,and Fourier transform infrared spectroscopy(FTIR).Furthermore,scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)was used to reveal the interfacial pore state and element distribution of the internal microstructure of concrete.The results show that PVA fiber bars can play the role of a“skeleton bridge”to improve the toughness of materials.LS can effectively promote the hydration process and cooperate with PVA fiber bars to enhance the mechanical properties of the material.EVA will inhibit the hydration reaction and degrade the material’s mechanical properties through the“organic isolation”effect.In addition,the on-site application has proven that the R3-group materials in this study can effectively inhibit the deformation of the roadway and possess strong reliability.Finally,the advantages and feasibility of LS-and-fiber-reinforced concrete were discussed from four perspectives:environmental protection,economy,disaster prevention,and development.This paper is expected to provide technical reference for the large-scale disposal of solid waste LS,the performance-optimization direction of concrete materials,and the prevention and control of coal and rock dynamic disasters.展开更多
The hot deformation behavior of GH3230 superalloy under selected deformation conditions ranging from 950 to 1150℃with strain rates ranging from 0.01 to 10 s^(–1)was studied through isothermal hot compression experim...The hot deformation behavior of GH3230 superalloy under selected deformation conditions ranging from 950 to 1150℃with strain rates ranging from 0.01 to 10 s^(–1)was studied through isothermal hot compression experiments.Based on the obtained flow stresses,a strain-compensated Arrhenius-type model was developed for the description of hot deformation behavior,and the consistency of the predicted flow stresses with the experimental values confirms the accuracy of the developed model.Furthermore,the processing maps were constructed and classified into the instability domain,low-dissipation stability domain and high-dissipation stability domain in accordance with the dynamic material model and the instability criterion.Microstructure observations indicated that the instability domain exhibits the adiabatic shear bands formation,and the low-power dissipation domain exhibits partial dynamic recrystallization(DRX),with the temperature increase/strain rate decrease being favorable for the DRX.The high-dissipation stability domain was occupied by uniformly fine equiaxed grains,and was identified as the optimal processing window,which corresponds to the deformation conditions at 1070–1150℃ with strain rates ranging from 0.01 to 0.15 s^(–1).Moreover,various DRX mechanisms are observed to occur during the hot deformation,which include the discontinuous dynamic recrystallization,characterized by nucleation at bulged boundaries,the continuous dynamic recrystallization with subgrain progressive rotation and the particle stimulated nucleation mechanism with stimulated nucleation of carbide particles.展开更多
Various slow slip events(SSEs)with distinct characteristics have been detected globally,particularly in regions with dense Global Navigation Satellite Systems(GNSS)networks.In the Hikurangi subduction zone of New Zeal...Various slow slip events(SSEs)with distinct characteristics have been detected globally,particularly in regions with dense Global Navigation Satellite Systems(GNSS)networks.In the Hikurangi subduction zone of New Zealand,SSEs frequently occur alongside seismic activity,especially in the Manawatu and Kapiti regions.This study analyzes the 2021-2023 Kapiti-Manawatu long-term SSE using daily displacement data(2019-2023)from 53 GPS stations.The network inversion filter(NIF)method is applied to extract slow slip signals,revealing spatial migration with alternating slip between Kapiti and Manawatu,characterized by distinct phases of acceleration and deceleration.Manawatu exhibits higher slip rates,exceeding 4 cm/month,with greater cumulative slip and surface displacement than Kapiti.A moderate temporal correlation(coefficient 0.59)between seismic activity in the region and slip acceleration in Manawatu suggests that seismic events may contribute to the slip,while no significant correlation is observed in Kapiti.展开更多
Marine organic-rich marl is not only a high-quality hydrocarbon source of conventional oil and gas,but also a new type and field of unconventional oil and gas exploration.An understanding of its pore structure evoluti...Marine organic-rich marl is not only a high-quality hydrocarbon source of conventional oil and gas,but also a new type and field of unconventional oil and gas exploration.An understanding of its pore structure evolution characteristics during a hydrocarbon generation process is theoretically significant and has application prospects for the exploration and development of this special type of natural gas reservoirs.This study conducted thermal simulation of hydrocarbon generation under near-geological conditions during a whole process for cylinder samples of low mature marine organic-rich marl in the Middle Devonian of Luquan,Yunnan Province,China.During this process,hydrocarbon products at different evolution stages were quantified and corresponding geochemical properties were analyzed.Simultaneously,field emission scanning electron microscopy(FE-SEM)and low-pressure gas adsorption(CO_(2),N_(2))tests were applied to the corresponding cylinder residue samples to reveal the mechanisms of different types of pore formation and evolution,and clarify the dynamic evolution processes of their pore systems.The results show that with an increase in temperature and pressure,the total oil yield peaks at an equivalent vitrinite reflectance(VR_(o))of 1.03%and is at the maximum retention stage of liquid hydrocarbons,which are 367.51 mg/g TOC and 211.67 mg/g TOC,respectively.The hydrocarbon gas yield increases continuously with an increase in maturity.The high retained oil rate at the peak of oil generation provides an abundant material basis for gas formation at high maturity and over-maturity stage.The lower limit of VR_(o)for organic matter(OM)pore mass development is about 1.6%,and bitumen pores,organic-clay complex pores together with intergranular pores,grain edge seams and dissolution pores constitute a complicated pore-seam-network system,which is the main reservoir space for unconventional carbonate gas.Pore formation and evolution are controlled synergistically by hydrocarbon generation,diagenesis and organic-inorganic interactions,and the pattern of pore structure evolution can be divided into four stages.A pore volume(PV)and a specific surface area(SSA)are at their highest values within the maturity range of 1.9%to 2.5%,which is conducive to exploring unconventional natural gas.展开更多
The Malvaceae family,the most diverse family in the order Malvales,consists of nine subfamilies.Within the Firmiana genus of the Sterculioideae subfamily,most species are considered globally vulnerable,yet their genom...The Malvaceae family,the most diverse family in the order Malvales,consists of nine subfamilies.Within the Firmiana genus of the Sterculioideae subfamily,most species are considered globally vulnerable,yet their genomes remain unexplored.Here,we present a chromosome-level genome assembly for a representative Firmiana species,F.hainanensis,2n=40,totaling 1536 Mb.Phylogenomic analysis shows that F.hainanensis and Durio zibethinus have the closest evolutionary relationship,with an estimated divergence time of approximately 21 millions of years ago(MYA)and distinct polyploidization events in their histories.Evolutionary trajectory analyses indicate that fissions and fusions may play a crucial role in chromosome number variation(2n=14 to 2n=96).Analysis of repetitive elements among Malvaceae reveals that the Tekay subfamily(belonging to the Gypsy group)contributes to variation in genome size(ranging from 324 Mb to 1620 Mb).Additionally,genes associated with P450,peroxidase,and microtubules,and thereby related to cell wall biosynthesis,are significantly contracted in F.hainanensis,potentially leading to its lower wood density relative to Hopea hainanensis.Overall,our study provides insights into the evolution of chromosome number,genome size,and the genetic basis of cell wall biosynthesis in Malvaceae species.展开更多
基金financially supported by the National Science Foundation of China(Nos.51974212 and 52274316)the China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202116)+1 种基金the Science and Technology Major Project of Wuhan(No.2023020302020572)the Foundation of Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education(No.FMRUlab23-04)。
文摘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%.
基金National Natural Science Foundation of China(U22A20191)。
文摘Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler metals is ever-increasing.It is of great significance to investigate the optimized composition design methods and to establish systematic design guidelines for brazing filler metals.This study elucidated the fundamental rules for the composition design of brazing filler metals from a three-dimensional perspective encompassing the basic properties of applied brazing filler metals,formability and processability,and overall cost.The basic properties of brazing filler metals refer to their mechanical properties,physicochemical properties,electromagnetic properties,corrosion resistance,and the wettability and fluidity during brazing.The formability and processability of brazing filler metals include the processes of smelting and casting,extrusion,rolling,drawing and ring-making,as well as the processes of granulation,powder production,and the molding of amorphous and microcrystalline structures.The cost of brazing filler metals corresponds to the sum of materials value and manufacturing cost.Improving the comprehensive properties of brazing filler metals requires a comprehensive and systematic consideration of design indicators.Highlighting the unique characteristics of brazing filler metals should focus on relevant technical indicators.Binary or ternary eutectic structures can effectively enhance the flow spreading ability of brazing filler metals,and solid solution structures contribute to the formability.By employing the proposed design guidelines,typical Ag based,Cu based,Zn based brazing filler metals,and Sn based solders were designed and successfully applied in major scientific and engineering projects.
基金funded by the National Natural Science Foundation of China(grant no.32270238 and 31870311).
文摘Subtropical evergreen broad-leaved trees are usually vulnerable to freezing stress,while hexaploid wild Camellia oleifera shows strong freezing tolerance.As a valuable genetic resource of woody oil crop C.oleifera,wild C.oleifera can serve as a case for studying the molecular bases of adaptive evolution to freezing stress.Here,47 wild C.oleifera from 11 natural distribution sites in China and 4 relative species of C.oleifera were selected for genome sequencing.“Min Temperature of Coldest Month”(BIO6)had the highest comprehensive contribution to wild C.oleifera distribution.The population genetic structure of wild C.oleifera could be divided into two groups:in cold winter(BIO6≤0℃)and warm winter(BIO6>0℃)areas.Wild C.oleifera in cold winter areas might have experienced stronger selection pressures and population bottlenecks with lower N_(e) than those in warm winter areas.155 singlenucleotide polymorphisms(SNPs)were significantly correlated with the key bioclimatic variables(106 SNPs significantly correlated with BIO6).Twenty key SNPs and 15 key copy number variation regions(CNVRs)were found with genotype differentiation>50%between the two groups of wild C.oleifera.Key SNPs in cis-regulatory elements might affect the expression of key genes associated with freezing tolerance,and they were also found within a CNVR suggesting interactions between them.Some key CNVRs in the exon regions were closely related to the differentially expressed genes under freezing stress.The findings suggest that rich SNPs and CNVRs in polyploid trees may contribute to the adaptive evolution to freezing stress.
基金Guizhou Province Science and Technology Plan Project(QKHJC-ZK[2024]yiban604)Guizhou Province Science and Technology Plan Project(CXTD[2021]008)+4 种基金Bijie City Science and Technology Project(BKLH[2023]9)Technology Project of Bijie City(BKLH[2023]36)Natural Science Research Project of Guizhou Higher Education Institutions of China(QJJ[2023]047)Science and Technology Project of Guizhou Department of Transportation(2022-121-011)Sanmenxia City Science and Technology Bureau Science and Technology Research Project(2022002005)。
文摘The microstructure evolution and deformation mechanism of a DZ125 superalloy during high-temperature creep were studied by means of microstructure observation and creep-property tests.The results show that at the initial stage of high-temperature creep,two sets of dislocations with different Burgers vectors move and meet inγmatrix channels,and react to form a quadrilateral dislocation network.Andγ′phases with raft-like microstructure are generated after the formation of dislocation networks.As creep progresses,the quadrilateral dislocation network is gradually transformed into hexagonal and quadrilateral dislocation networks.During steady stage of creep,the superalloy undergoes deformation with the mechanism that a great number of dislocations slip and climb in the matrix across the raft-likeγ′phases.At the later stage of creep,the raft-likeγ′phases are sheared by dislocations at the breakage of dislocation networks,and then alternate slip occurs,which distorts and breaks the raft-likeγ′/γphases,resulting in the accumulation of micropores at the raft-likeγ′/γinterfaces and the formation of microcracks.As creep continues,the microcracks continue to expand until creep fracture occurs,which is the damage and fracture mechanism of the alloy at the later stage of creep at high temperature.
文摘This paper is about the transformation process of theoretical frameworks used in educational research on teaching evolution. To this end, some authors' claims, findings and suggestions offered via particular studies are evaluated. While the evaluated authors have represented secularism as a barrier to teaching evolution in the United States, they have also offered pedagogically theistic or agnostic evolution as the best choice for the reconciliation of religion and evolution. This paper is particularly concerned with one of the explanatory theoretical frameworks—religious cultural competence in evolution education(ReCCEE), which is derived from the cultural competence framework—although others are visited as well. Even though the schools or authors who have applied ReCCEE do not directly reference constructivism, their studies are built upon constructivist pedagogy and epistemological idealism. They often have problematic issues such as obscurantism, ad hominem attacks, cherry-picking and an ill-formed appeal to authority. Besides, these papers present biased or uncritical views and ill-informed definitions of some terms, such as secularism and agnosticism.
文摘The study of the oxygen evolution reaction(OER)mechanism is vital for advancing our understanding of this pivotal energy conversion process.This review synthesizes recent advancements in OER mechanism,emphasizing the intricate relationship between catalytic mechanisms and catalyst design.This review discusses the connotation and cutting-edge progress of traditional mechanisms such as adsorbate evolution mechanism(AEM)and lattice oxygen mechanism(LOM)as well as emerging pathways including oxide path mechanism(OPM),oxo-oxo coupling mechanism(OCM),and intramolecular oxygen coupling mechanism(IMOC)etc.Innovative research progress on the coexistence and transformation of multiple mechanisms is highlighted,and the intrinsic factors that influence these dynamic processes are summarized.Advanced characterization techniques and theoretical modeling are underscored as indispensable tools for revealing these complex interactions.This review provides guiding principles for mechanism-based catalyst design.Finally,in view of the multidimensional challenges currently faced by OER mechanisms,prospects for future research are given to bridge the gap between mechanism innovation and experimental verification and application.This comprehensive review provides valuable perspectives for advancing clean energy technologies and achieving sustainable development.
基金financially supported by the National Natural Science Foundation of China (Grant No. 42072150)
文摘To accurately investigate the evolution characteristics and generation mechanism of retained oil,the study analyzed organic-rich lacustrine shale samples from the Paleogene Kongdian Formation in Cangdong Sag,Bohai Bay Basin.This analysis involves Rock-Eval pyrolysis,pyrolysis simulation experiments,Gas Chromatograph Mass Spectrometer(GC-MS),and reactive molecular dynamics simulations(ReaxFF).The results revealed the retained oil primarily consisted of n-alkanes with carbon numbers ranging from C14 to C36.The generation of retained oil occurred through three stages.A slow growth stage of production rate was observed before reaching the peak of oil production in Stage Ⅰ.Stage Ⅱ involved a rapid increase in oil retention,with C12-C17 and C24-C32 serving as the primary components,increasing continuously during the pyrolysis process.The generation process involved the cleavage of weak bonds,including bridging bonds(hydroxyl,oxy,peroxy,imino,amino,and nitro),ether bonds,and acid amides in the first stage(Ro=0.50%-0.75%).The carbon chains in aromatic ring structures with heteroatomic functional groups breaks in the second stage(R_(o)=0.75%-1.20%).In the third stage(R_(o)=1.20%-2.50%),the ring structures underwent ring-opening reactions to synthesize iso-short-chain olefins and radicals,while further breakdown of aliphatic chains occurred.By coupling pyrolysis simu-lation experiments and molecular simulation technology,the evolution characteristics and bond breaking mechanism of retained oil in three stages were revealed,providing a reference for the for-mation and evolution mechanism of retained oil.
基金supported by the National Natural Science Foundation of China(Grants No.W2412144,42271292)the 111 project,and the Fundamental Research Funds for the Central Universities of China.
文摘Amid ongoing global environmental change and the critical pursuit of sustainable development,human-environment systems are exhibiting increasingly complex dynamic evolutions and spatial relationships,underscoring an urgent need for innovative research frameworks.Integrated geography synthesizes physical geography,human geography,and geographic information science,providing key frameworks for understanding complex human-environment systems.This editorial proposes an emerging research framework for integrated geography—“Composite driving-System evolution-Coupling mechanism-Synergistic regulation(CSCS)”—based on key issues such as climate change,biodiversity loss,resource scarcity,and social-ecological interactions,which have been highlighted in both recent critical literature on human-environment systems and UN assessment reports.The framework starts with diverse composite driving forces,extends to the evolution of human-environment system structures,processes,and functions that these drivers induce,explores couplings within human-environment systems,and calls for regulation aimed at sustainable development in synergies.Major research frontiers include understanding the cascading“evolution-coupling”effects of shocks;measuring system resilience,thresholds,and safe and just operating space boundaries;clarifying linkage mechanisms across scales;and achieving synergistic outcomes for multi-objective sustainability.This framework will help promote the interdisciplinary integration and development of integrated geography,and provide geographical solutions for the global sustainable development agenda.
基金jointly supported financially by the National Natural Science Foundation of China(No.41603040)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2023-JC-YB-239)Fundamental Research Funds for the Central Universities(S202310710204)。
文摘The Bijigou intrusion is one of the largest and most well-differentiated Fe–Ti oxide-bearing layered intrusions in the Hannan massif located in the northwestern margin of the Yangtze Block,South China.Besides the mineralization-related mafic-ultramafic rocks,the intermediate-acid intrusive rocks are also exposed in the mining area,which is of great significance for the understanding the Neoproterozoic tectonic evolution of the Yangtze Block,but studies on these intermediate-acid rocks are scarce.The Bijigou mafic-ultramafic layered intrusion is surrounded by granite and cut by syenite veins.Here,we report new zircon U-Pb ages,Lu-Hf isotope composition and bulk rock geochemical data of the Bijigou syenite vein and wall-rock granite in the northwestern margin of the Yangtze Block.Laser ablation inductively coupled plasma mass spectrometry(LAICP-MS)zircon U-Pb dating results show that the Bijigou syenite vein and wall-rock granite formed at 770±3.5 Ma(MSWD=0.17,n=28)and 810±4 Ma(MSWD=0.84,n=26),respectively.The zirconεHf(t)values of the syenite veins range from+1.52 to+5.33(average of+3.05),combined with its high potassium contents,negative Nb–Ta anomalies and positive Pb anomalies,suggesting that they may have originated from mantle-derived basaltic magma,which was modified by materials from subducting oceanic slab.The zirconεHf(t)and T_(DM2)ages of the wall-rock granite range from+0.71 to+5.71(average+3.06)and 1344 to 1659 Ma(average 1519 Ma),respectively,indicating that the granite was produced by partial melting of juvenile crust.The geochemical characteristics of the Bijigou syenite and granite indicate that they were formed in a continental margin arc setting.Thus,combined with previous studies,it suggests that there was a major subduction system along the northwestern margin of the Yangtze Block during 824-720 Ma,and the magmatism in the Hannan massif was divided into two episodes:(1)early magmatism(824-790 Ma),such as the Bijigou,Hongmiaozhen and Huangguanzhen granitoids,was derived from partial melting of the juvenile or pre-existing crust in a continental arc setting;(2)later magmatism(789-718 Ma),including Bijigou syenite,Wudumen,Erliba and Zushidian granitoids,formed in a subduction-related back-arc extensional environment.The long-term subduction system along the northwestern margin of the Yangtze Block during 824-720 Ma suggests that the Yangtze Block was previously located at the periphery of the Rodinia supercontinent.
基金supported by the National Natural Science Foundation of China(72471240).
文摘When performing tasks,unmanned clusters often face a variety of strategy choices.One of the key issues in unmanned cluster tasks is the method through which to design autonomous collaboration and cooperative evolution mechanisms that allow for unmanned clusters to maximize their overall task effective-ness under the condition of strategic diversity.This paper ana-lyzes these task requirements from three perspectives:the diver-sity of the decision space,information network construction,and the autonomous collaboration mechanism.Then,this paper pro-poses a method for solving the problem of strategy selection diversity under two network structures.Next,this paper presents a Moran-rule-based evolution dynamics model for unmanned cluster strategies and a vision-driven-mechanism-based evolu-tion dynamics model for unmanned cluster strategy in the con-text of strategy selection diversity according to various unmanned cluster application scenarios.Finally,this paper pro-vides a simulation analysis of the effects of relevant parameters such as the payoff factor and cluster size on cooperative evolu-tion in autonomous cluster collaboration for the two types of models.On this basis,this paper presents advice for effectively addressing diverse choices in unmanned cluster tasks,thereby providing decision support for practical applications of unmanned cluster tasks.
基金funded by National Special Project Number for International Cooperation under Grant 2015DFR11050the Applied Science and Technology Research and Development Special Fund Project of Guangdong Province under Grant 2016B010126004.
文摘Differential evolution(DE)algorithms are simple and efficient evolutionary algorithms that performwell in various optimization problems.Unfortunately,they inevitably stagnate when differential evolutionary algorithms are used to solve complex problems(e.g.,real-world artificial neural network(ANN)training problems).To resolve this issue,this paper proposes a framework based on an efficient elite centroid operator.It continuously monitors the current state of the population.Once stagnation is detected,two dedicated operators,centroid-based mutation(CM)and centroid-based crossover(CX),are executed to replace the classical mutation and binomial crossover operations in DE.CM and CX are centred on the elite centroid composed of multiple elite individuals,constituting a framework consisting of elitism centroid-based operations(CMX)to improve the performance of the individuals who fall into stagnation.In CM,elite centroid provide evolutionary direction for stagnant individuals,and in CX,elite plasmoids address the limitation that stagnant individuals can only obtain limited information about the population.The CMX framework is simple enough to easily incorporate into both classically well-known DEs with constant population sizes and state-of-the-art DEs with varying populations.Numerical experiments on benchmark functions show that the proposed CMX method can significantly enhance the classical DE algorithm and its advanced variants in solving the stagnation problem and improving performance.
基金National Natural Science Foundation of China,No.42122006, No.41971154, No.42271201Key Project of National Natural Science Foundation of China,No.41731278。
文摘Globalization has resulted in a notable rise in the flow of high-skilled talent from emerging countries to developed nations. Current research on transnational talent flow mainly focuses on the destination countries, with less attention given to the perspective of the sending countries, particularly lacking a dynamic discussion on its impact on technological evolution in the origin countries. Based on the OECD REGPAT database, this paper aims to explore how talent groups migrating to developed countries facilitate the return of knowledge and technology to emerging countries and achieve breakthroughs in their technological evolution paths, while further discussing the potential mechanisms involved. The findings of this paper are as follows:(1) The technological development of emerging countries is a path-dependent process, where countries often branch into new technologies related to their preexisting knowledge base. Consequently, knowledge feedback from high-skilled talents increases the likelihood of sending countries developing unrelated technologies.(2) The mobility of talents across borders fosters more international collaborations and citations for patents that are unrelated to the local knowledge base, thus enriching the technological paths of sending countries.(3) The mobility of high-skilled talents primarily affects complex technologies, which have significant economic effects that encourage imitation by other countries.However, the effect on novel technologies is less significant due to their strong geographical stickiness. In general, this paper addresses the gaps in existing research on talent outflow and the technological evolution of origin countries, providing empirical evidence for the positive role of transnational talent mobility in the technological catch-up of emerging nations.Besides, it offers recommendations for talent export, import, and innovation policy formulation in these countries.
基金supported by the National Key Research and Development Project of China(No.2021YFC3000600)。
文摘The Longmenshan structural belt on the eastern edge of the Tibetan Plateau experienced the impactful Mw7.92008 Wenchuan Earthquake,causing a 350 km surface rupture.Traditional models attribute this to the Beichuan and Pengguan faults,but our research reveals a complex fault system at the northern end,with inconsistencies in surface rupture,aftershock distribution,and focal mechanisms.We integrate shallow geology,active source seismic reflection,and magnetotelluric profiling to establish a deep structural model for the northern end of the Longmenshan structural belt.This area exhibits dominant reverse thrust nappe tectonics,and analyzing the tectonic evolution history provides insights into deformation propagation from the orogenic belt toward the Sichuan Basin.Focal mechanism analysis and relocated aftershock data reveals two distinct types of seismogenic structures in the northern end of the Longmenshan structural belt.In the middle to northern segments,the reverse fault type is attributed to reactivated pre-existing faults.Conversely,at the northern end,the strike-slip fault type originates from high-angle co-seismic rupture cutting through pre-existing reverse faults.This study enhances our understanding of fault complexity and seismic mechanisms in the northeastern Longmenshan structural belt,providing new insights into regional tectonics.
文摘Data clustering is an essential technique for analyzing complex datasets and continues to be a central research topic in data analysis.Traditional clustering algorithms,such as K-means,are widely used due to their simplicity and efficiency.This paper proposes a novel Spiral Mechanism-Optimized Phasmatodea Population Evolution Algorithm(SPPE)to improve clustering performance.The SPPE algorithm introduces several enhancements to the standard Phasmatodea Population Evolution(PPE)algorithm.Firstly,a Variable Neighborhood Search(VNS)factor is incorporated to strengthen the local search capability and foster population diversity.Secondly,a position update model,incorporating a spiral mechanism,is designed to improve the algorithm’s global exploration and convergence speed.Finally,a dynamic balancing factor,guided by fitness values,adjusts the search process to balance exploration and exploitation effectively.The performance of SPPE is first validated on CEC2013 benchmark functions,where it demonstrates excellent convergence speed and superior optimization results compared to several state-of-the-art metaheuristic algorithms.To further verify its practical applicability,SPPE is combined with the K-means algorithm for data clustering and tested on seven datasets.Experimental results show that SPPE-K-means improves clustering accuracy,reduces dependency on initialization,and outperforms other clustering approaches.This study highlights SPPE’s robustness and efficiency in solving both optimization and clustering challenges,making it a promising tool for complex data analysis tasks.
基金supported by the National Natural Science Foundation of China(Nos.U23B2093 and 52034009)the National Key R&D Program of China(No.2024YFC3013801)the Fundamental Research Funds for the Central Universities(Ph.D.Top Innovative Talents Fund of CUMTB)(No.BBJ2025001).
文摘Coal and rock dynamic disasters are always major hidden dangers threatening mine safety production.Many researchers use cement concrete material as filling and energy-absorption materials.However,the current material toughness is not sufficient to meet the requirements of mine disaster prevention.Based on this,in order to find the optimal-ratio material that combines strength and toughness,the synergistic mechanism of lithium slag(LS),ethylene-vinyl acetate(EVA)copolymer,and polyvinyl alcohol(PVA)fiber mixtures in improving the mechanical properties of cement concrete,as well as the mechanism of microscopic phase evolution,was analyzed through macroscopic experiments,mesoscopic characterization,microscopic analysis,theoretical calculations,and comprehensive evaluation.The stress-strain curves obtained from the uniaxial compressive strength tests of specimens with different admixtures and fibers were investigated,and the characteristics of different stages were analyzed.The mechanical properties of different admixtures and fiber-reinforced materials,including their advantages and disadvantages,were compared through weighted comprehensive evaluation.The entire process of material failure,ranging from pore compaction,crack initiation,crack propagation,specimen instability to crack penetration,was explained via macroscopic fracture morphology,and the mechanical mechanism of how different admixtures affect the mechanical properties of concrete materials was revealed.The microscopic mechanism and the phase-evolution process of how the admixture affects concrete properties were elucidated using X-ray diffraction(XRD),hydration reaction theory,and Fourier transform infrared spectroscopy(FTIR).Furthermore,scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)was used to reveal the interfacial pore state and element distribution of the internal microstructure of concrete.The results show that PVA fiber bars can play the role of a“skeleton bridge”to improve the toughness of materials.LS can effectively promote the hydration process and cooperate with PVA fiber bars to enhance the mechanical properties of the material.EVA will inhibit the hydration reaction and degrade the material’s mechanical properties through the“organic isolation”effect.In addition,the on-site application has proven that the R3-group materials in this study can effectively inhibit the deformation of the roadway and possess strong reliability.Finally,the advantages and feasibility of LS-and-fiber-reinforced concrete were discussed from four perspectives:environmental protection,economy,disaster prevention,and development.This paper is expected to provide technical reference for the large-scale disposal of solid waste LS,the performance-optimization direction of concrete materials,and the prevention and control of coal and rock dynamic disasters.
基金the National Key Research and Development Program of China(No.2016YFB0700505)the National Natural Science Foundation of China(No.51571020).
文摘The hot deformation behavior of GH3230 superalloy under selected deformation conditions ranging from 950 to 1150℃with strain rates ranging from 0.01 to 10 s^(–1)was studied through isothermal hot compression experiments.Based on the obtained flow stresses,a strain-compensated Arrhenius-type model was developed for the description of hot deformation behavior,and the consistency of the predicted flow stresses with the experimental values confirms the accuracy of the developed model.Furthermore,the processing maps were constructed and classified into the instability domain,low-dissipation stability domain and high-dissipation stability domain in accordance with the dynamic material model and the instability criterion.Microstructure observations indicated that the instability domain exhibits the adiabatic shear bands formation,and the low-power dissipation domain exhibits partial dynamic recrystallization(DRX),with the temperature increase/strain rate decrease being favorable for the DRX.The high-dissipation stability domain was occupied by uniformly fine equiaxed grains,and was identified as the optimal processing window,which corresponds to the deformation conditions at 1070–1150℃ with strain rates ranging from 0.01 to 0.15 s^(–1).Moreover,various DRX mechanisms are observed to occur during the hot deformation,which include the discontinuous dynamic recrystallization,characterized by nucleation at bulged boundaries,the continuous dynamic recrystallization with subgrain progressive rotation and the particle stimulated nucleation mechanism with stimulated nucleation of carbide particles.
基金funded by the National Natural Science Foundation of China(41704031,42374040)the Natural Science Foundation of Jiangxi Science and Technology Department(20232BAB203073)the Key Laboratory of Mine Environmental Monitoring and Improving around Poyang Lake,Ministry of Natural Resources(MEMI-2021-2022-29).
文摘Various slow slip events(SSEs)with distinct characteristics have been detected globally,particularly in regions with dense Global Navigation Satellite Systems(GNSS)networks.In the Hikurangi subduction zone of New Zealand,SSEs frequently occur alongside seismic activity,especially in the Manawatu and Kapiti regions.This study analyzes the 2021-2023 Kapiti-Manawatu long-term SSE using daily displacement data(2019-2023)from 53 GPS stations.The network inversion filter(NIF)method is applied to extract slow slip signals,revealing spatial migration with alternating slip between Kapiti and Manawatu,characterized by distinct phases of acceleration and deceleration.Manawatu exhibits higher slip rates,exceeding 4 cm/month,with greater cumulative slip and surface displacement than Kapiti.A moderate temporal correlation(coefficient 0.59)between seismic activity in the region and slip acceleration in Manawatu suggests that seismic events may contribute to the slip,while no significant correlation is observed in Kapiti.
基金supported by the National Natural Science Foundation of China(Grant No.41930426)。
文摘Marine organic-rich marl is not only a high-quality hydrocarbon source of conventional oil and gas,but also a new type and field of unconventional oil and gas exploration.An understanding of its pore structure evolution characteristics during a hydrocarbon generation process is theoretically significant and has application prospects for the exploration and development of this special type of natural gas reservoirs.This study conducted thermal simulation of hydrocarbon generation under near-geological conditions during a whole process for cylinder samples of low mature marine organic-rich marl in the Middle Devonian of Luquan,Yunnan Province,China.During this process,hydrocarbon products at different evolution stages were quantified and corresponding geochemical properties were analyzed.Simultaneously,field emission scanning electron microscopy(FE-SEM)and low-pressure gas adsorption(CO_(2),N_(2))tests were applied to the corresponding cylinder residue samples to reveal the mechanisms of different types of pore formation and evolution,and clarify the dynamic evolution processes of their pore systems.The results show that with an increase in temperature and pressure,the total oil yield peaks at an equivalent vitrinite reflectance(VR_(o))of 1.03%and is at the maximum retention stage of liquid hydrocarbons,which are 367.51 mg/g TOC and 211.67 mg/g TOC,respectively.The hydrocarbon gas yield increases continuously with an increase in maturity.The high retained oil rate at the peak of oil generation provides an abundant material basis for gas formation at high maturity and over-maturity stage.The lower limit of VR_(o)for organic matter(OM)pore mass development is about 1.6%,and bitumen pores,organic-clay complex pores together with intergranular pores,grain edge seams and dissolution pores constitute a complicated pore-seam-network system,which is the main reservoir space for unconventional carbonate gas.Pore formation and evolution are controlled synergistically by hydrocarbon generation,diagenesis and organic-inorganic interactions,and the pattern of pore structure evolution can be divided into four stages.A pore volume(PV)and a specific surface area(SSA)are at their highest values within the maturity range of 1.9%to 2.5%,which is conducive to exploring unconventional natural gas.
基金supported by the National Key R&D Program of China(2022YFF1001400)postdoctoral innovative talents support program(517000-X92308)+2 种基金the specific research fund of The Innovation Platform for Academicians of Hainan Province(YSPTZX202154,YSPTZX202139)the Research Startup Funding from Hainan Institute of Zhejiang University(0202-6602-A12201)the Distinguished Discipline Support Program of Zhejiang University(226-2024-00205,226-2022-00100).
文摘The Malvaceae family,the most diverse family in the order Malvales,consists of nine subfamilies.Within the Firmiana genus of the Sterculioideae subfamily,most species are considered globally vulnerable,yet their genomes remain unexplored.Here,we present a chromosome-level genome assembly for a representative Firmiana species,F.hainanensis,2n=40,totaling 1536 Mb.Phylogenomic analysis shows that F.hainanensis and Durio zibethinus have the closest evolutionary relationship,with an estimated divergence time of approximately 21 millions of years ago(MYA)and distinct polyploidization events in their histories.Evolutionary trajectory analyses indicate that fissions and fusions may play a crucial role in chromosome number variation(2n=14 to 2n=96).Analysis of repetitive elements among Malvaceae reveals that the Tekay subfamily(belonging to the Gypsy group)contributes to variation in genome size(ranging from 324 Mb to 1620 Mb).Additionally,genes associated with P450,peroxidase,and microtubules,and thereby related to cell wall biosynthesis,are significantly contracted in F.hainanensis,potentially leading to its lower wood density relative to Hopea hainanensis.Overall,our study provides insights into the evolution of chromosome number,genome size,and the genetic basis of cell wall biosynthesis in Malvaceae species.
