煤矿甲烷排放遥感监测已经成为世界各国监测温室气体排放的主要研究内容之一。为系统总结以往研究,分析研究趋势和发现当今研究热点,首先利用Web of Science与中国知网(CNKI)数据库和关键词检索,筛选了2000—2024年煤矿甲烷排放遥感监...煤矿甲烷排放遥感监测已经成为世界各国监测温室气体排放的主要研究内容之一。为系统总结以往研究,分析研究趋势和发现当今研究热点,首先利用Web of Science与中国知网(CNKI)数据库和关键词检索,筛选了2000—2024年煤矿甲烷排放遥感监测领域的国内外文献;然后,采用CiteSpace文献计量工具进行文献计量和可视化分析。结果表明:煤矿甲烷遥感监测领域文献呈显著增长态势,年均增幅达20%;发文量排名靠前的国家为美国(181篇)和中国(98篇),德国、加拿大等国家紧随其后;美国国家航空航天局(NASA)以66篇发文量居机构首位,中国科学院位列全球第6;研究热点主要集中于卫星遥感监测、甲烷浓度反演、甲烷量化估算以及数据智能处理;国外研究更多聚焦于全球甲烷排放的监测及政策驱动下的技术创新,我国则在煤矿甲烷排放监测和智能化管理方面表现突出;根据文献共被引分析,高分辨率遥感与反演技术的发展显著提升了甲烷排放监测的时空精度,遥感监测精度和效率、数据智能化处理与算法、多平台集成与融合、国际合作和数据共享等为未来研究方向。展开更多
The ongoing revolution in information technology is reshaping human life. In the realm of health behavior, wearable technology emerges as a leading digital solution,capturing physical behaviors (i.e., physical activit...The ongoing revolution in information technology is reshaping human life. In the realm of health behavior, wearable technology emerges as a leading digital solution,capturing physical behaviors (i.e., physical activity, sedentary habits, sleep patterns) within the 24-h cycle of daily life. Wearables are applied in research, clinical practice, and as lifestyle devices;most obvious, they promise to be a key element for increasing human physical activity, one of the biggest health challenges nowadays.展开更多
New and perhaps unexpected progress in rate-independent elastoplastic modeling is reported with a unified approach toward simulating widely ranging non-elastic effects of various advanced engineering materials such as...New and perhaps unexpected progress in rate-independent elastoplastic modeling is reported with a unified approach toward simulating widely ranging non-elastic effects of various advanced engineering materials such as metals,shape memory alloys,granular materials,fiber-reinforced composites,as well as crystalline solids,etc.This progress originates from a simple idea of bypassing inherent limitations of usual elastoplastic formulations centered on the notion of yielding.With no reference to any yield criteria,the plastic strain-rate should be induced at all stress levels in a more realistic sense that it is small for stresses within a classical yield surface and becomes appreciable for stresses close to and on this surface.A new and unified flow rule for the plastic strain-rate is then proposed of the same smooth form for all cases of both the stress level and the stress rate.Without imposing the ad hoc simplified conditions introduced in usual Prandtl-Reuss equations,new elastoplastic equations are then established by incorporating such small deviations from realistic behaviors as neglected just by postulating these conditions.It turns out that the new equations are not only essentially simpler in both conceptual and structural formulations,but can automatically as inherent response features incorporate significant effects excluded from usual Prandtl-Reuss equations,such as the yielding and unloading behaviors with smooth transitions,the pseudo-elastic effect with hysteresis loops,the non-elastic recovery during unloading as well as failure effects under either monotone or cyclic loading conditions,etc.Since such effects not only go beyond the scope of usual elastoplastic equations but can be only partially simulated even if augmented constitutive equations are postulated toward further characterizing damaging and fracturing effects resulting from evolving micro-defects and macro-cracks,it may be probably surprising that now the new equations of essentially simpler structure not only can in a unified manner simulate all these effects but also can bypass numerical complexities in integrating various rate constitutive equations of complex structures.New results in treating long-standing issues in a few respects are presented,including(i)the yielding and the unloading behaviors with smooth transitions,(ii)the non-elastic recovery during unloading,(iii)the pseudo-elastic effect as extraordinary Bauschinger effect,(iv)failure effects under monotone and cyclic loading,(v)anisotropic multi-mode failure effects of unidirectional composites,(vi)new formulation of crystal elastoplasticity without involving non-uniqueness and singularity issues,(vii)non-normality effects for non-proportional multi-axial loading cases,and(viii)high efficiency algorithms for simulating multi-axial fatigue effects.展开更多
We present a case report of laparoscopic herniorrhaphy in an infant with ovarian prolapse. Using this case study, we demonstrate the role of the ovarian ligamentous apparatus. A structure appearing like the male guber...We present a case report of laparoscopic herniorrhaphy in an infant with ovarian prolapse. Using this case study, we demonstrate the role of the ovarian ligamentous apparatus. A structure appearing like the male gubernaculum was identified. The anatomical and functional role of this “gubernaculum” will be the subject of discussion. Further detailed laparoscopic examinations are indicated to better understand the ligamentous anatomy of ovarian prolapse.展开更多
Edge computing is swiftly gaining traction and is being standardised by the European Telecommunications Standards Institute(ETSI)as Multi-access Edge Computing(MEC).Simultaneously,oneM2M has been actively developing s...Edge computing is swiftly gaining traction and is being standardised by the European Telecommunications Standards Institute(ETSI)as Multi-access Edge Computing(MEC).Simultaneously,oneM2M has been actively developing standards for dynamic data management and IoT services at the edge,particularly for applications that require real-time support and security.Integrating MEC and oneM2M offers a unique opportunity to maximize their individual strengths.Therefore,this article proposes a framework that integrates MEC and oneM2M standard platforms for IoT applications,demonstrating how the synergy of these architectures can leverage the geographically distributed computing resources at base stations,enabling efficient deployment and added value for time-sensitive IoT applications.In addition,this study offers a concept of potential interworking models between oneM2M and the MEC architectures.The adoption of these standard architectures can enable various IoT edge services,such as smart city mobility and real-time analytics functions,by leveraging the oneM2M common service layer instantiated on the MEC host.展开更多
The Heilongjiang Complex in northeast China(NE China)separates the Jiamusi and Songliao blocks and marks the suture zone of the former Mudanjiang Ocean,as evidenced by a variety of oceanic basalt-derived blueschists.U...The Heilongjiang Complex in northeast China(NE China)separates the Jiamusi and Songliao blocks and marks the suture zone of the former Mudanjiang Ocean,as evidenced by a variety of oceanic basalt-derived blueschists.Understanding the closure history of the Mudanjiang Ocean is crucial to unravelling the tectonic transition from the final amalgamation of the Central Asian Orogenic Belt(CAOB)to the onset of the Paleo-Pacific subduction.In this study,we investigate epidote-ferroglaucophane(Ep-Fgl)and garnet-ferrobarroisite(Grt-Fbrs)schists from the Yilan area of the Heilongjiang Complex through petrological,mineralogical,thermodynamic modelling,whole-rock geochemical,and geochronological analyses.The Ep-Fgl schists preserve a peak assemblage of ferroglaucophane+epidote+chlorite+clinopyroxene+phengite+titanite with peak P-T conditions of 13.5-15.8 kbar and 458-495℃.On the other hand,the Grt-Fbrs schists exhibit a peak assemblage of garnet+glaucophane/ferroglaucophane+lawsonite+chlorite+phengite+rutile±clinopyroxene±titanite,deriving peak P-T conditions of 16.4-18.3 kbar and 457-475℃.Both types of schist record similar clockwise P-T paths,with three metamorphic stages:a peak epidote-to-lawsonite blueschist-facies stage,a post-peak decompression stage in the epidote amphibolite-facies,and a late greenschist-facies overprint stage.The Ep-Fgl schists display alkaline OIB-like geochemical affinities,while the Grt-Fbrs schists show tholeiitic MORB-like characteristics,suggesting that the protoliths represent fragments of the Mudanjiang oceanic crust.Magmatic zircon grains from Ep-Fgl schists yield protolith ages of 276±1 Ma and 280±1 Ma,whereas zircon of Grt-Fbrs schists document protolith ages of 249±2 Ma and 248±2 Ma,indicating that the Mudanjiang Ocean existed since at least the early Permian.Reconstruction of the metamorphic P-T evolution,combined with previous magmatic and metamorphic age data from rocks of the Heilongjiang Complex and of adjacent tectonic units suggests that the subduction and eventual closure of the Mudanjiang Ocean occurred between the late Triassic and middle Jurassic,driven by a regional stress regime shift caused by the westward subduction of the Paleo-Pacific Plate beneath Eurasia.展开更多
The quasi-rectangular tunnel represents a novel cross-section design,intended to supersede the traditional circular and rectangular tunnel formats.Due to the limited capacity of the tunnel vault to withstand vertical ...The quasi-rectangular tunnel represents a novel cross-section design,intended to supersede the traditional circular and rectangular tunnel formats.Due to the limited capacity of the tunnel vault to withstand vertical loads,an interior column is often installed at the center to enhance its load-bearing capacity.This study aims to develop a hyperstatic reaction method(HRM)for the analysis of deformation and structural integrity in this specific tunnel type.The computational model is validated through comparison with the corresponding finite element method(FEM)analysis.Following comprehensive validation,an ensemble machine learning(ML)model is proposed,using numerical benchmark data,to facilitate real-time design and optimization.Subsequently,three widely used ensemble models,i.e.random forest(RF),gradient boosting decision tree(GBDT),and extreme gradient boosting(XGBoost)are compared to identify the most efficient ML model for replacing the HRM model in the design optimization process.The performance metrics,such as the coefficient of determination R2 of about 0.999 and the mean absolute percentage error(MAPE)of about 1%,indicate that XGBoost outperforms the others,exhibiting excellent agreement with the HRM analysis.Additionally,the model demonstrates high computational efficiency,with prediction times measured in seconds.Finally,the HRM-XGBoost model is integrated with the well-known particle swarm optimization(PSO)for the real-time design optimization of quasi-rectangular tunnels,both with and without the interior column.A feature importance assessment is conducted to evaluate the sensitivity of design input features,enabling the selection of the most critical features for the optimization task.展开更多
A microscopic understanding of the complex solute-defect interaction is pivotal for optimizing the alloy’s macroscopic mechanical properties.Simulating solute segregation in a plastically deformed crystalline system ...A microscopic understanding of the complex solute-defect interaction is pivotal for optimizing the alloy’s macroscopic mechanical properties.Simulating solute segregation in a plastically deformed crystalline system at atomic resolution remains challenging.The objective is to efficiently model and predict a phys-ically informed segregated solute distribution rather than simulating a series of diffusion kinetics.To ad-dress this objective,we coupled molecular dynamics(MD)and Monte Carlo(MC)methods using a novel method based on virtual atoms technique.We applied our MD-MC coupling approach to model off-lattice carbon(C)solute segregation in nanoindented Fe-C samples containing complex dislocation networks.Our coupling framework yielded the final configuration through efficient parallelization and localized en-ergy computations,showing C Cottrell atmospheres near dislocations.Different initial C concentrations resulted in a consistent trend of C atoms migrating from less crystalline distortion to high crystalline distortion regions.Besides unraveling the strong spatial correlation between local C concentration and defect regions,our results revealed two crucial aspects of solute segregation preferences:(1)defect ener-getics hierarchy and(2)tensile strain fields near dislocations.The proposed approach is generic and can be applied to other material systems as well.展开更多
The first in vivo measurements of serial sarcomere number in human muscles before and after eccentric strength training have just been published and the results will interest anyone involved with sport or health:Train...The first in vivo measurements of serial sarcomere number in human muscles before and after eccentric strength training have just been published and the results will interest anyone involved with sport or health:Training the hamstrings 3 times per week for 9 weeks with the Nordic hamstring exercise was found to increase the number of sarcomeres in series in the biceps femoris long head(BFlh)by≥25%.1 In this commentary,we highlight an additional,paradoxical finding,which was not discussed by the authors;namely that the substantial serial sarcomere addition must have been accompanied by a subtraction of sarcomeres in parallel to match the relatively small increase in muscle volume after training.展开更多
To investigate the structural configuration of^(6)He and^(6)Be in a three-cluster system and to highlight dinucleon correlations,we performed a two-cluster overlap amplitude(TCOA)calculation,which is an extension of t...To investigate the structural configuration of^(6)He and^(6)Be in a three-cluster system and to highlight dinucleon correlations,we performed a two-cluster overlap amplitude(TCOA)calculation,which is an extension of the RWA formalism.The total wave functions were obtained using the generator coordinate method with microscopic cluster wave functions.Based on these wave functions,we calculated the overlap amplitudes to extract the relative motion and spatial correlations between clusters.The computed energy spectra showed reasonable agreement with the experimental data,emphasizing the effectiveness of the present framework for investigating dinucleon correlations in light nuclei.Our results revealed the presence of both dinucleon-like and cigar-like configurations in the ground states of^(6)He and^(6)Be,indicating a coexistence of compact and extended cluster structures.Furthermore,the 2_(1)^(+)state of^(6)He revealed a pronounced dineutron structure,with strong spatial correlations between the two valence neutrons.We also performed calculations for the higher-lying 2_(1)^(+)state,which showed a more spatially extended structure and provided potential references for future experimental investigations.These findings demonstrated that the TCOA method served as a powerful tool to explore cluster dynamics and dinucleon features in light,weakly bound nuclear systems.展开更多
Understanding the complex interactions between urbanization and ecosystem services(ESs)is crucial for optimiz ing planning policies and achieving sustainable urban management.While previous research has largely focuse...Understanding the complex interactions between urbanization and ecosystem services(ESs)is crucial for optimiz ing planning policies and achieving sustainable urban management.While previous research has largely focused on highly urbanized areas,little attention has been given to the phased effect of progressive urbanization on ES networks.This study proposes a conceptual framework that utilizes the network method and space-time replace ment to examine the effect of urbanization on the complex relationships among ESs at different stages,with a particular emphasis on the progressive evolution of the process.We apply this framework to the Horqin area,a typical eco-fragile area in China.Results demonstrate that the connectivity of the ES synergy network exhibits a non-stationary characteristic,initially increasing,then decreasing,and subsequently strengthening.Meanwhile,its modularity shows a rising trend during periods of accelerated urbanization.The performance of the trade off network displays the opposite pattern.Additionally,we observe a gradual replacement of provisioning and regulation services by cultural services in terms of dominance in the synergy network as urbanization advances.By providing guidance for identifying key planning initiatives and implementing ecological protection policies at different stages of development,this study contributes a pathway that can inform development strategies in other regions undergoing progressive urbanization.展开更多
Due to high theoretical specific capacity and excellent thermal stability,transition metal phosphides(TMPs)have emerged as highly promising candidates of anode materials for advancing lithium-ion batteries.However,it ...Due to high theoretical specific capacity and excellent thermal stability,transition metal phosphides(TMPs)have emerged as highly promising candidates of anode materials for advancing lithium-ion batteries.However,it remains confronted with significant challenges,including large volume expansion,low specific surface area and limited electron conductivity,which hinder their practical application in the field of energy storage.Herein,nitrogen,phosphoric-codoped carbon nanosheets decorated with cobalt phosphide nanoparticles(CoP/N,P-C)are synthesized through a simple and environment-friendly synthesis method demonstrating their potential as anode materials for lithium-ion batteries.The element-doped carbon matrix can enhance electrical conductivity,accelerate ion transport,improve the active sites,and buffer the volume expansion of CoP nanoparticles,collectively leading to significantly improved electrochemical performance.The prepared CoP/N,P-C electrodes present outstanding electrochemical performance,delivering a discharge specific capacity of 920 mAh g^(-1)after 100 cycles at 0.1 A g^(-1)and 686mAh g^(-1)after 3,000 cycles even at 2.0 A g^(-1).The quantitative kinetic analysis result reveals that pseudo-capacitance dominates total capacity behavior(70.6%at 0.5 mV s-1).Furthermore,the galvanostatic intermittent titration technique(GITT)is applied to prove the super-fast diffusion coefficient of the electrodes.This work provides a simplified and environmentally friendly method for effective modification of the comprehensive properties of transition metal phosphates.展开更多
We sincerely thank the authors of the commentary1 for their thoughtful analysis and constructive critique of our systematic review on ischemic preconditioning(IPC)and placebo effects in exercise capacity and athletic ...We sincerely thank the authors of the commentary1 for their thoughtful analysis and constructive critique of our systematic review on ischemic preconditioning(IPC)and placebo effects in exercise capacity and athletic performance.2Their attention to methodological details,particularly concerning the inclusion and timing of warm-up protocols across studies,is commendable and contributes meaningfully to the ongoing refinement of IPC research in sports science.展开更多
Background:Ischemic preconditioning(IPC)is purported to have beneficial effects on athletic performance,although findings are inconsistent,with some studies reporting placebo effects.The majority of studies have inves...Background:Ischemic preconditioning(IPC)is purported to have beneficial effects on athletic performance,although findings are inconsistent,with some studies reporting placebo effects.The majority of studies have investigated IPC alongside a placebo condition,but without a control condition that was devoid of experimental manipulation,thereby limiting accurate determination of the IPC effects.Therefore,the aims of this study were to assess the impact of the IPC intervention,compared to both placebo and no intervention,on exercise capacity and athletic performance.Methods:A systematic search of PubMed,Embase,SPORTDiscus,Cochrane Library,and Latin American and Caribbean Health Sciences Literature(LILACS)covering records from their inception until July 2023 was conducted.To qualify for inclusion,studies had to apply IPC as an acute intervention,comparing it with placebo and/or control conditions.Outcomes of interest were performance(force,number of repetitions,power,time to exhaustion,and time trial performance),physiological measurements(maximum oxygen consumption,and heart rate),or perceptual measurements(RPE).For each outcome measure,we conducted 3 independent meta-analyses(IPC vs.placebo,IPC vs.control,placebo vs.control)using an inverse-variance random-effects model.The between-treatment effects were quantified by the standardized mean difference(SMD),accompanied by their respective 95%confidence intervals.Additionally,we employed the Grading of Recommendations,Assessment,Development and Evaluation(GRADE)approach to assess the level of certainty in the evidence.Results:Seventy-nine studies were included in the quantitative analysis.Overall,IPC demonstrates a comparable effect to the placebo condition(using a low-pressure tourniquet),irrespective of the subjects'training level(all outcomes presenting p>0.05),except for the outcome of time to exhaustion,which exhibits a small magnitude effect(SMD=0.37;p=0.002).Additionally,the placebo exhibited effects notably greater than the control condition(outcome:number of repetitions;SMD=0.45;p=0.03),suggesting a potential influence of participants'cognitive perception on the outcomes.However,the evidence is of moderate to low certainty,regardless of the comparison or outcome.Conclusion:IPC has significant effects compared to the control intervention,but it did not surpass the placebo condition.Its administration might be influenced by the cognitive perception of the receiving subject,and the efficacy of IPC as an ergogenic strategy for enhancing exercise capacity and athletic performance remains questionable.展开更多
In recent years,(0001)twist grain boundaries(BTGBs)located in primary α grain clusters were identified as fatigue crack nucleation sites in different Ti alloys.In the present study,crack initiation was investigated i...In recent years,(0001)twist grain boundaries(BTGBs)located in primary α grain clusters were identified as fatigue crack nucleation sites in different Ti alloys.In the present study,crack initiation was investigated in a bimodal Ti-5Al-4 V alloy subjected to low-cycle fatigue and dwell-fatigue loadings at room temperature.The low fraction of primary α grains was not associated with a lack of sensitivity to BTGB cracking.Transmission electron microscopy and electron back-scattered diffraction were used to characterize BTGBs in the initial microstructure.The fatigue mechanisms were then analyzed with a focus on dislocation activity.α_(p) grains adjacent to cracked BTGBs contained a high dislocation density.It was primarily composed of planar slip bands of dislocations.In addition,<c+a>dislocations were noticed in the vicinity of cracked BTGBs.They supposedly pertain to crack tip plasticity during growth,and no evidence of a role of an incoming slip event in crack nucleation was obtained.Also,basal slip bands extending across adjacent grains were found to emerge from BTGBs.This feature provides an easier path for crack extension when growth along the grain boundary becomes difficult owing to a deviation from the basal plane.Atom probe tomography analyses evidenced V and Fe segregation at a grain boundary with a significant deviation from the BTGB configuration.This suggests a possible contribution of local solute segregation to the high cracking resistance of general α_(p)/α_(p) grain boundaries.This work provides new insights into the mechanisms involved in cracking of BTGB in Ti alloys subjected to cyclic loadings.展开更多
Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids(P-type),or by replacement of magmatic protoliths(R-type)in subduction zones.They are valuable targets for investigating the mobility ...Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids(P-type),or by replacement of magmatic protoliths(R-type)in subduction zones.They are valuable targets for investigating the mobility behavior and chemical composition of subduction zone fluids.The Rio San Juan Complex(RSJC)in the northern Dominican Republic hosts both P-and R-type jadeitites and jadeite-rich rocks,which provide ideal samples for addressing such issues.Here,we present trace element and Sr-Nd-O-Si isotope compositions of RSJC jadeitites and related rocks.Most samples show similar REE patterns,trace element distributions and δ^(18)O values to those of plagiogranite protoliths,indicating the predominance of R-type origin in RSJC.The P-type samples exhibit slightly higherδ^(30)Si values(−0.15‰to 0.25‰)than that of R-type samples(−0.20‰to 0.08‰),which place above the igneous array.The low(^(87)Sr/^(86)Sr)_(i)(0.70346 to 0.70505)and highεNd(t)values(4.6 to 6.8)of the P-type jadeitites and quartzites,along with relatively lowδ^(18)O values(4.7‰to 6.4‰)of their forming fluids,indicate that the fluids are likely derived from the altered basaltic crust rather than from oceanic sediment.However,the estimated jadeitite-and quartzite-forming fluids exhibit distinctδ^(30)Si values(0.76‰to 0.99‰and-0.48‰to-0.08‰,respectively),implying an evolution of the fluids that modified the Si isotopic compositions.Since fluid metasomatism and related desilication process could have lowered the whole-rock δ^(30)Si values,the heavy Si isotope compositions of the R-type samples are produced from the external fluids.Combing Rayleigh distillation and binary mixing simulations,we propose that fluids derived from altered oceanic crust obtained high δ^(30)Si values after crystallization of minerals enriched in light Si isotopes.The P-type jadeitites are formed through direct precipitation from this fluid.As the plagiogranite protoliths were continuously replaced by this fluid,the formed R-type samples(jadeitites and quartzites)also exhibit high δ^(30)Si values.Such rocks could significantly alter the Si isotope compositions of local mantle when they are deeply subducted at convergent plate margins.展开更多
The buckling-guided three-dimensional(3D)assembly method has arisen increasing attention for its advantages in forming complex 3D architectures with a rich diversity of geometric shapes in a broad spectrum of inorgani...The buckling-guided three-dimensional(3D)assembly method has arisen increasing attention for its advantages in forming complex 3D architectures with a rich diversity of geometric shapes in a broad spectrum of inorganic functional materials.Such an assembly method relies on the controlled lateral bucking of a 2D precursor structure integrated with a pre-stretched substrate at selective regions.In the assembly process,the preservation or break-ing of rotational symmetry is crucial for understanding the mechanism of 2D-to-3D geometric transformation.Here,we present a fundamental study on the rotational symmetry of 3D spoke double-ring structures formed through buckling-guided assembly.An energetic method is introduced to analyze the rotational symmetry and to understand the symmetry-breaking mechanism.Such symmetry-breaking phenomenon is validated by experi-ments and finite element analyses(FEA).Phase diagrams of the deformation mode are established to shed light on the influences of various geometric parameters(e.g.,initial rotational symmetry order,radius ratio,and lo-cation of bonding sites).This work offers new insights into the underlying mechanism of 2D-to-3D geometric transformation in ribbon-type structures formed by compressive buckling.展开更多
Transition metal-doped CeO_(2)catalysts exhibit great potentials for the selective catalytic reduction(SCR)of nitrogen oxide(NOx)with NH_(3)(NH_(3)-SCR).However,traditional research mainly relies on a lot of experimen...Transition metal-doped CeO_(2)catalysts exhibit great potentials for the selective catalytic reduction(SCR)of nitrogen oxide(NOx)with NH_(3)(NH_(3)-SCR).However,traditional research mainly relies on a lot of experiments to find out effective catalysts,which wastes a lot of time and resources.Screening out effective CeO_(2)-based catalysts for low-temperature NH_(3)-SCR via density functional theory(DFT)calculations is crucial for the rational design and synthesis of efficient catalysts.Herein,transition metal(M=Co,Cr,Cu,Fe,Mn,Mo,Nb,Ni,Ta,Ti,V,and W)-doped CeO_(2)catalysts were screened out via accelerated DFT calculations for NH_(3)-SCR of nitric-oxide(NO)using three theoretical terms;(i)an adsorption energy of NH_(3),(ii)an adsorption energy of NO,and(iii)the reaction energies between NO with O_(2)and lattice oxygen.The theoretically predicted trend in catalytic performance is as follows:CeO_(2)-Mn,-Cu,-Mo>CeO_(2)-Fe,-Co,-Ni,-V,-Cr>CeO_(2)-W,-Ti>CeO_(2)-Nb,-Ta.The theoretical prediction was well verified via experimental NH_(3)-SCR activity of NO at low temperatures(90–300℃),demonstrating CeO_(2)-Mo as efficient NH_(3)-SCR catalyst across a broad temperature range.Temperature-programmed desorption of NH_(3)and in situ diffuse reflectance infrared Fourier transforms spectroscopy further indicated that metal doping significantly enhanced the NH_(3)adsorption capacity and strength of CeO_(2)in the medium-to low-temperature range.Consequently,accelerated DFT calculations provide a useful tool with great potentials for predicting the catalytic performance.展开更多
The Southern Granulite Terrane(Dharwar Craton),South India,is a key unit for understanding the origin of charnockite.New U-Pb and Lu-Hf analyses in zircon crys-tals from 16 samples representing a wide variety of litho...The Southern Granulite Terrane(Dharwar Craton),South India,is a key unit for understanding the origin of charnockite.New U-Pb and Lu-Hf analyses in zircon crys-tals from 16 samples representing a wide variety of litho-types from the quarries in Kabbaldurga reveal a complex geological history in the Archean and early Paleoprotero-zoic.Magmatic protoliths predominantly record Paleoar-chean ages between 3.4 and 3.2 Ga.Combined U-Pb and Lu-Hf signatures indicate a history of recurrent crustal anatexis,juvenile magmatic input,and felsic injections.Mesoarchaean magmatic charnockites were generated mainly from hornblende-dehydration melting of Paleoar-chaean mafic rocks.In addition,Peninsular Gneissic Com-plex of the Dharwar Craton,commonly described as TTG suites,are likely generated by melting of hydrated basalt.The new data are consistent with the idea of a convecting magmatic cycle and also support the proposal that the southern Dharwar Craton comprises a tilted cross-sec-tion through the Archaean crust.Paleoproterozoic high-temperature event is documented here as a complex unit involving juvenile mafic magmatism,granulite facies imprints and crustal anatexis as well as felsic injections,occurring within a short time period around 2.5 Ga.展开更多
文摘煤矿甲烷排放遥感监测已经成为世界各国监测温室气体排放的主要研究内容之一。为系统总结以往研究,分析研究趋势和发现当今研究热点,首先利用Web of Science与中国知网(CNKI)数据库和关键词检索,筛选了2000—2024年煤矿甲烷排放遥感监测领域的国内外文献;然后,采用CiteSpace文献计量工具进行文献计量和可视化分析。结果表明:煤矿甲烷遥感监测领域文献呈显著增长态势,年均增幅达20%;发文量排名靠前的国家为美国(181篇)和中国(98篇),德国、加拿大等国家紧随其后;美国国家航空航天局(NASA)以66篇发文量居机构首位,中国科学院位列全球第6;研究热点主要集中于卫星遥感监测、甲烷浓度反演、甲烷量化估算以及数据智能处理;国外研究更多聚焦于全球甲烷排放的监测及政策驱动下的技术创新,我国则在煤矿甲烷排放监测和智能化管理方面表现突出;根据文献共被引分析,高分辨率遥感与反演技术的发展显著提升了甲烷排放监测的时空精度,遥感监测精度和效率、数据智能化处理与算法、多平台集成与融合、国际合作和数据共享等为未来研究方向。
基金funded in part by the German Research Foundation(Grant reference:496846758).
文摘The ongoing revolution in information technology is reshaping human life. In the realm of health behavior, wearable technology emerges as a leading digital solution,capturing physical behaviors (i.e., physical activity, sedentary habits, sleep patterns) within the 24-h cycle of daily life. Wearables are applied in research, clinical practice, and as lifestyle devices;most obvious, they promise to be a key element for increasing human physical activity, one of the biggest health challenges nowadays.
基金the German Science Foundation(DFG)for supportFuyao University of Science and Technology of Fujian,China+1 种基金supported by the National Natural Science Foundation of China(Grant Nos.12172149 and 12172151)the Ministry of Science and Technology of China(Grant No.G20221990122)。
文摘New and perhaps unexpected progress in rate-independent elastoplastic modeling is reported with a unified approach toward simulating widely ranging non-elastic effects of various advanced engineering materials such as metals,shape memory alloys,granular materials,fiber-reinforced composites,as well as crystalline solids,etc.This progress originates from a simple idea of bypassing inherent limitations of usual elastoplastic formulations centered on the notion of yielding.With no reference to any yield criteria,the plastic strain-rate should be induced at all stress levels in a more realistic sense that it is small for stresses within a classical yield surface and becomes appreciable for stresses close to and on this surface.A new and unified flow rule for the plastic strain-rate is then proposed of the same smooth form for all cases of both the stress level and the stress rate.Without imposing the ad hoc simplified conditions introduced in usual Prandtl-Reuss equations,new elastoplastic equations are then established by incorporating such small deviations from realistic behaviors as neglected just by postulating these conditions.It turns out that the new equations are not only essentially simpler in both conceptual and structural formulations,but can automatically as inherent response features incorporate significant effects excluded from usual Prandtl-Reuss equations,such as the yielding and unloading behaviors with smooth transitions,the pseudo-elastic effect with hysteresis loops,the non-elastic recovery during unloading as well as failure effects under either monotone or cyclic loading conditions,etc.Since such effects not only go beyond the scope of usual elastoplastic equations but can be only partially simulated even if augmented constitutive equations are postulated toward further characterizing damaging and fracturing effects resulting from evolving micro-defects and macro-cracks,it may be probably surprising that now the new equations of essentially simpler structure not only can in a unified manner simulate all these effects but also can bypass numerical complexities in integrating various rate constitutive equations of complex structures.New results in treating long-standing issues in a few respects are presented,including(i)the yielding and the unloading behaviors with smooth transitions,(ii)the non-elastic recovery during unloading,(iii)the pseudo-elastic effect as extraordinary Bauschinger effect,(iv)failure effects under monotone and cyclic loading,(v)anisotropic multi-mode failure effects of unidirectional composites,(vi)new formulation of crystal elastoplasticity without involving non-uniqueness and singularity issues,(vii)non-normality effects for non-proportional multi-axial loading cases,and(viii)high efficiency algorithms for simulating multi-axial fatigue effects.
文摘We present a case report of laparoscopic herniorrhaphy in an infant with ovarian prolapse. Using this case study, we demonstrate the role of the ovarian ligamentous apparatus. A structure appearing like the male gubernaculum was identified. The anatomical and functional role of this “gubernaculum” will be the subject of discussion. Further detailed laparoscopic examinations are indicated to better understand the ligamentous anatomy of ovarian prolapse.
基金supported by the Institute of Information&Communications Technology Planning&Evaluation(IITP)-Information Technology Research Center(ITRC)grant funded by the Korea government(IITP-2025-RS-2021-II211816)supported by the National Research Foundation of Korea(NRF)grant(NRF-2023R1A2C1004453)+3 种基金funded by the European Union’s HORIZON-JUSNS-2023 HE research and innovation program(6G-Path project,Grant No.101139172)the Horizon 2020 Research and Innovation Program(aerOS project,Grant No.101069732)supported by the ESTIMED project,conducted by the ETSI Specialist Task Force 685(STF 685)funded by the European Commission(EC)and the European Free Trade Association(EFTA).
文摘Edge computing is swiftly gaining traction and is being standardised by the European Telecommunications Standards Institute(ETSI)as Multi-access Edge Computing(MEC).Simultaneously,oneM2M has been actively developing standards for dynamic data management and IoT services at the edge,particularly for applications that require real-time support and security.Integrating MEC and oneM2M offers a unique opportunity to maximize their individual strengths.Therefore,this article proposes a framework that integrates MEC and oneM2M standard platforms for IoT applications,demonstrating how the synergy of these architectures can leverage the geographically distributed computing resources at base stations,enabling efficient deployment and added value for time-sensitive IoT applications.In addition,this study offers a concept of potential interworking models between oneM2M and the MEC architectures.The adoption of these standard architectures can enable various IoT edge services,such as smart city mobility and real-time analytics functions,by leveraging the oneM2M common service layer instantiated on the MEC host.
基金the support of Yajing Mao and Lingquan Zhao during the preparation of the manuscript.This research was financially supported by the National Natural Science Foundation of China(No.U2244206).
文摘The Heilongjiang Complex in northeast China(NE China)separates the Jiamusi and Songliao blocks and marks the suture zone of the former Mudanjiang Ocean,as evidenced by a variety of oceanic basalt-derived blueschists.Understanding the closure history of the Mudanjiang Ocean is crucial to unravelling the tectonic transition from the final amalgamation of the Central Asian Orogenic Belt(CAOB)to the onset of the Paleo-Pacific subduction.In this study,we investigate epidote-ferroglaucophane(Ep-Fgl)and garnet-ferrobarroisite(Grt-Fbrs)schists from the Yilan area of the Heilongjiang Complex through petrological,mineralogical,thermodynamic modelling,whole-rock geochemical,and geochronological analyses.The Ep-Fgl schists preserve a peak assemblage of ferroglaucophane+epidote+chlorite+clinopyroxene+phengite+titanite with peak P-T conditions of 13.5-15.8 kbar and 458-495℃.On the other hand,the Grt-Fbrs schists exhibit a peak assemblage of garnet+glaucophane/ferroglaucophane+lawsonite+chlorite+phengite+rutile±clinopyroxene±titanite,deriving peak P-T conditions of 16.4-18.3 kbar and 457-475℃.Both types of schist record similar clockwise P-T paths,with three metamorphic stages:a peak epidote-to-lawsonite blueschist-facies stage,a post-peak decompression stage in the epidote amphibolite-facies,and a late greenschist-facies overprint stage.The Ep-Fgl schists display alkaline OIB-like geochemical affinities,while the Grt-Fbrs schists show tholeiitic MORB-like characteristics,suggesting that the protoliths represent fragments of the Mudanjiang oceanic crust.Magmatic zircon grains from Ep-Fgl schists yield protolith ages of 276±1 Ma and 280±1 Ma,whereas zircon of Grt-Fbrs schists document protolith ages of 249±2 Ma and 248±2 Ma,indicating that the Mudanjiang Ocean existed since at least the early Permian.Reconstruction of the metamorphic P-T evolution,combined with previous magmatic and metamorphic age data from rocks of the Heilongjiang Complex and of adjacent tectonic units suggests that the subduction and eventual closure of the Mudanjiang Ocean occurred between the late Triassic and middle Jurassic,driven by a regional stress regime shift caused by the westward subduction of the Paleo-Pacific Plate beneath Eurasia.
基金funded by the Hanoi University of Mining and Geology(Grant No.T23-44)The research is also funded by the German Research Foundation(DFG e Project number 518862444)in collaboration with the Vietnam National Foundation for Science and Technology Development(NAFOSTED)under grant number DFG.105e2022.03The third author was funded by the Postdoctoral Scholarship Program of the Vingroup Innovation Foundation(VINIF)(VINIF.2023.STS.15).
文摘The quasi-rectangular tunnel represents a novel cross-section design,intended to supersede the traditional circular and rectangular tunnel formats.Due to the limited capacity of the tunnel vault to withstand vertical loads,an interior column is often installed at the center to enhance its load-bearing capacity.This study aims to develop a hyperstatic reaction method(HRM)for the analysis of deformation and structural integrity in this specific tunnel type.The computational model is validated through comparison with the corresponding finite element method(FEM)analysis.Following comprehensive validation,an ensemble machine learning(ML)model is proposed,using numerical benchmark data,to facilitate real-time design and optimization.Subsequently,three widely used ensemble models,i.e.random forest(RF),gradient boosting decision tree(GBDT),and extreme gradient boosting(XGBoost)are compared to identify the most efficient ML model for replacing the HRM model in the design optimization process.The performance metrics,such as the coefficient of determination R2 of about 0.999 and the mean absolute percentage error(MAPE)of about 1%,indicate that XGBoost outperforms the others,exhibiting excellent agreement with the HRM analysis.Additionally,the model demonstrates high computational efficiency,with prediction times measured in seconds.Finally,the HRM-XGBoost model is integrated with the well-known particle swarm optimization(PSO)for the real-time design optimization of quasi-rectangular tunnels,both with and without the interior column.A feature importance assessment is conducted to evaluate the sensitivity of design input features,enabling the selection of the most critical features for the optimization task.
基金the funding from the Ger-man Research Foundation(DFG)-BE 5360/1-1 and ThyssenKrupp Europe.
文摘A microscopic understanding of the complex solute-defect interaction is pivotal for optimizing the alloy’s macroscopic mechanical properties.Simulating solute segregation in a plastically deformed crystalline system at atomic resolution remains challenging.The objective is to efficiently model and predict a phys-ically informed segregated solute distribution rather than simulating a series of diffusion kinetics.To ad-dress this objective,we coupled molecular dynamics(MD)and Monte Carlo(MC)methods using a novel method based on virtual atoms technique.We applied our MD-MC coupling approach to model off-lattice carbon(C)solute segregation in nanoindented Fe-C samples containing complex dislocation networks.Our coupling framework yielded the final configuration through efficient parallelization and localized en-ergy computations,showing C Cottrell atmospheres near dislocations.Different initial C concentrations resulted in a consistent trend of C atoms migrating from less crystalline distortion to high crystalline distortion regions.Besides unraveling the strong spatial correlation between local C concentration and defect regions,our results revealed two crucial aspects of solute segregation preferences:(1)defect ener-getics hierarchy and(2)tensile strain fields near dislocations.The proposed approach is generic and can be applied to other material systems as well.
文摘The first in vivo measurements of serial sarcomere number in human muscles before and after eccentric strength training have just been published and the results will interest anyone involved with sport or health:Training the hamstrings 3 times per week for 9 weeks with the Nordic hamstring exercise was found to increase the number of sarcomeres in series in the biceps femoris long head(BFlh)by≥25%.1 In this commentary,we highlight an additional,paradoxical finding,which was not discussed by the authors;namely that the substantial serial sarcomere addition must have been accompanied by a subtraction of sarcomeres in parallel to match the relatively small increase in muscle volume after training.
基金supported by the National Key R&D Program of China(Nos.2023YFA1606701 and 2022YFA1602402)the National Natural Science Foundation of China(Nos.12175042,11890710,11890714,12047514,12147101,and 12347106)+1 种基金Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030008)the 111 Project。
文摘To investigate the structural configuration of^(6)He and^(6)Be in a three-cluster system and to highlight dinucleon correlations,we performed a two-cluster overlap amplitude(TCOA)calculation,which is an extension of the RWA formalism.The total wave functions were obtained using the generator coordinate method with microscopic cluster wave functions.Based on these wave functions,we calculated the overlap amplitudes to extract the relative motion and spatial correlations between clusters.The computed energy spectra showed reasonable agreement with the experimental data,emphasizing the effectiveness of the present framework for investigating dinucleon correlations in light nuclei.Our results revealed the presence of both dinucleon-like and cigar-like configurations in the ground states of^(6)He and^(6)Be,indicating a coexistence of compact and extended cluster structures.Furthermore,the 2_(1)^(+)state of^(6)He revealed a pronounced dineutron structure,with strong spatial correlations between the two valence neutrons.We also performed calculations for the higher-lying 2_(1)^(+)state,which showed a more spatially extended structure and provided potential references for future experimental investigations.These findings demonstrated that the TCOA method served as a powerful tool to explore cluster dynamics and dinucleon features in light,weakly bound nuclear systems.
基金supported by the National Natural Science Foundation Projects of China(Grant No.42071284).
文摘Understanding the complex interactions between urbanization and ecosystem services(ESs)is crucial for optimiz ing planning policies and achieving sustainable urban management.While previous research has largely focused on highly urbanized areas,little attention has been given to the phased effect of progressive urbanization on ES networks.This study proposes a conceptual framework that utilizes the network method and space-time replace ment to examine the effect of urbanization on the complex relationships among ESs at different stages,with a particular emphasis on the progressive evolution of the process.We apply this framework to the Horqin area,a typical eco-fragile area in China.Results demonstrate that the connectivity of the ES synergy network exhibits a non-stationary characteristic,initially increasing,then decreasing,and subsequently strengthening.Meanwhile,its modularity shows a rising trend during periods of accelerated urbanization.The performance of the trade off network displays the opposite pattern.Additionally,we observe a gradual replacement of provisioning and regulation services by cultural services in terms of dominance in the synergy network as urbanization advances.By providing guidance for identifying key planning initiatives and implementing ecological protection policies at different stages of development,this study contributes a pathway that can inform development strategies in other regions undergoing progressive urbanization.
基金financially supported by the National Natural Science Foundation of China(Nos.52207249 and 52472131)the Excellent Youth Innovation Team Project for Higher Education Institutions of Shandong Province(No.2023KJ238)+2 种基金the Major basic research project of Natural Science Foundation of Shandong Province(Nos.ZR2023ZD12 and ZR2023ZD13)Yantai Basic Research Project(No.2022JCYJ04)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai(No.AMGM2024F27)
文摘Due to high theoretical specific capacity and excellent thermal stability,transition metal phosphides(TMPs)have emerged as highly promising candidates of anode materials for advancing lithium-ion batteries.However,it remains confronted with significant challenges,including large volume expansion,low specific surface area and limited electron conductivity,which hinder their practical application in the field of energy storage.Herein,nitrogen,phosphoric-codoped carbon nanosheets decorated with cobalt phosphide nanoparticles(CoP/N,P-C)are synthesized through a simple and environment-friendly synthesis method demonstrating their potential as anode materials for lithium-ion batteries.The element-doped carbon matrix can enhance electrical conductivity,accelerate ion transport,improve the active sites,and buffer the volume expansion of CoP nanoparticles,collectively leading to significantly improved electrochemical performance.The prepared CoP/N,P-C electrodes present outstanding electrochemical performance,delivering a discharge specific capacity of 920 mAh g^(-1)after 100 cycles at 0.1 A g^(-1)and 686mAh g^(-1)after 3,000 cycles even at 2.0 A g^(-1).The quantitative kinetic analysis result reveals that pseudo-capacitance dominates total capacity behavior(70.6%at 0.5 mV s-1).Furthermore,the galvanostatic intermittent titration technique(GITT)is applied to prove the super-fast diffusion coefficient of the electrodes.This work provides a simplified and environmentally friendly method for effective modification of the comprehensive properties of transition metal phosphates.
文摘We sincerely thank the authors of the commentary1 for their thoughtful analysis and constructive critique of our systematic review on ischemic preconditioning(IPC)and placebo effects in exercise capacity and athletic performance.2Their attention to methodological details,particularly concerning the inclusion and timing of warm-up protocols across studies,is commendable and contributes meaningfully to the ongoing refinement of IPC research in sports science.
基金partially supported by the State Funding Agency of Minas Gerais,Brazil(FAPEMIG),Process No.APQ-01811-21supported by Alexander von Humboldt-Stiftung(AvH)/Coordena??o de Aperfei?oamento de Pessoal de Nível Superior(CAPES)+1 种基金National Council for Scientific and Technological Development-CNPq(Process No.308138/2022-8)supported by National Council for Scientific and Technological Development-CNPq(Process No.BPD-00905-22).
文摘Background:Ischemic preconditioning(IPC)is purported to have beneficial effects on athletic performance,although findings are inconsistent,with some studies reporting placebo effects.The majority of studies have investigated IPC alongside a placebo condition,but without a control condition that was devoid of experimental manipulation,thereby limiting accurate determination of the IPC effects.Therefore,the aims of this study were to assess the impact of the IPC intervention,compared to both placebo and no intervention,on exercise capacity and athletic performance.Methods:A systematic search of PubMed,Embase,SPORTDiscus,Cochrane Library,and Latin American and Caribbean Health Sciences Literature(LILACS)covering records from their inception until July 2023 was conducted.To qualify for inclusion,studies had to apply IPC as an acute intervention,comparing it with placebo and/or control conditions.Outcomes of interest were performance(force,number of repetitions,power,time to exhaustion,and time trial performance),physiological measurements(maximum oxygen consumption,and heart rate),or perceptual measurements(RPE).For each outcome measure,we conducted 3 independent meta-analyses(IPC vs.placebo,IPC vs.control,placebo vs.control)using an inverse-variance random-effects model.The between-treatment effects were quantified by the standardized mean difference(SMD),accompanied by their respective 95%confidence intervals.Additionally,we employed the Grading of Recommendations,Assessment,Development and Evaluation(GRADE)approach to assess the level of certainty in the evidence.Results:Seventy-nine studies were included in the quantitative analysis.Overall,IPC demonstrates a comparable effect to the placebo condition(using a low-pressure tourniquet),irrespective of the subjects'training level(all outcomes presenting p>0.05),except for the outcome of time to exhaustion,which exhibits a small magnitude effect(SMD=0.37;p=0.002).Additionally,the placebo exhibited effects notably greater than the control condition(outcome:number of repetitions;SMD=0.45;p=0.03),suggesting a potential influence of participants'cognitive perception on the outcomes.However,the evidence is of moderate to low certainty,regardless of the comparison or outcome.Conclusion:IPC has significant effects compared to the control intervention,but it did not surpass the placebo condition.Its administration might be influenced by the cognitive perception of the receiving subject,and the efficacy of IPC as an ergogenic strategy for enhancing exercise capacity and athletic performance remains questionable.
基金financially supported by the National Natural Science Foundation of China(No.U21A2050)support of the Chinese Scholarship Council(No.202006290165).
文摘In recent years,(0001)twist grain boundaries(BTGBs)located in primary α grain clusters were identified as fatigue crack nucleation sites in different Ti alloys.In the present study,crack initiation was investigated in a bimodal Ti-5Al-4 V alloy subjected to low-cycle fatigue and dwell-fatigue loadings at room temperature.The low fraction of primary α grains was not associated with a lack of sensitivity to BTGB cracking.Transmission electron microscopy and electron back-scattered diffraction were used to characterize BTGBs in the initial microstructure.The fatigue mechanisms were then analyzed with a focus on dislocation activity.α_(p) grains adjacent to cracked BTGBs contained a high dislocation density.It was primarily composed of planar slip bands of dislocations.In addition,<c+a>dislocations were noticed in the vicinity of cracked BTGBs.They supposedly pertain to crack tip plasticity during growth,and no evidence of a role of an incoming slip event in crack nucleation was obtained.Also,basal slip bands extending across adjacent grains were found to emerge from BTGBs.This feature provides an easier path for crack extension when growth along the grain boundary becomes difficult owing to a deviation from the basal plane.Atom probe tomography analyses evidenced V and Fe segregation at a grain boundary with a significant deviation from the BTGB configuration.This suggests a possible contribution of local solute segregation to the high cracking resistance of general α_(p)/α_(p) grain boundaries.This work provides new insights into the mechanisms involved in cracking of BTGB in Ti alloys subjected to cyclic loadings.
基金supported by funds from the National Key Research and Development Program of China(Grant No.2024YFF0807302)National Natural Science Foundation of China(42273043,42173003)the International Visiting Professorship of USTC(2024BVR23).
文摘Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids(P-type),or by replacement of magmatic protoliths(R-type)in subduction zones.They are valuable targets for investigating the mobility behavior and chemical composition of subduction zone fluids.The Rio San Juan Complex(RSJC)in the northern Dominican Republic hosts both P-and R-type jadeitites and jadeite-rich rocks,which provide ideal samples for addressing such issues.Here,we present trace element and Sr-Nd-O-Si isotope compositions of RSJC jadeitites and related rocks.Most samples show similar REE patterns,trace element distributions and δ^(18)O values to those of plagiogranite protoliths,indicating the predominance of R-type origin in RSJC.The P-type samples exhibit slightly higherδ^(30)Si values(−0.15‰to 0.25‰)than that of R-type samples(−0.20‰to 0.08‰),which place above the igneous array.The low(^(87)Sr/^(86)Sr)_(i)(0.70346 to 0.70505)and highεNd(t)values(4.6 to 6.8)of the P-type jadeitites and quartzites,along with relatively lowδ^(18)O values(4.7‰to 6.4‰)of their forming fluids,indicate that the fluids are likely derived from the altered basaltic crust rather than from oceanic sediment.However,the estimated jadeitite-and quartzite-forming fluids exhibit distinctδ^(30)Si values(0.76‰to 0.99‰and-0.48‰to-0.08‰,respectively),implying an evolution of the fluids that modified the Si isotopic compositions.Since fluid metasomatism and related desilication process could have lowered the whole-rock δ^(30)Si values,the heavy Si isotope compositions of the R-type samples are produced from the external fluids.Combing Rayleigh distillation and binary mixing simulations,we propose that fluids derived from altered oceanic crust obtained high δ^(30)Si values after crystallization of minerals enriched in light Si isotopes.The P-type jadeitites are formed through direct precipitation from this fluid.As the plagiogranite protoliths were continuously replaced by this fluid,the formed R-type samples(jadeitites and quartzites)also exhibit high δ^(30)Si values.Such rocks could significantly alter the Si isotope compositions of local mantle when they are deeply subducted at convergent plate margins.
基金supported by the National Natural Science Foundation of China(Grant Nos.12225206,11921002,and 12202233)the New Cornerstone Science Foundation through the XPLORER PRIZE,the Tsinghua National Laboratory for Information Science and Technology,a grant from the Institute for Guo Qiang,Tsinghua University(Grant No.2021GQG1009)。
文摘The buckling-guided three-dimensional(3D)assembly method has arisen increasing attention for its advantages in forming complex 3D architectures with a rich diversity of geometric shapes in a broad spectrum of inorganic functional materials.Such an assembly method relies on the controlled lateral bucking of a 2D precursor structure integrated with a pre-stretched substrate at selective regions.In the assembly process,the preservation or break-ing of rotational symmetry is crucial for understanding the mechanism of 2D-to-3D geometric transformation.Here,we present a fundamental study on the rotational symmetry of 3D spoke double-ring structures formed through buckling-guided assembly.An energetic method is introduced to analyze the rotational symmetry and to understand the symmetry-breaking mechanism.Such symmetry-breaking phenomenon is validated by experi-ments and finite element analyses(FEA).Phase diagrams of the deformation mode are established to shed light on the influences of various geometric parameters(e.g.,initial rotational symmetry order,radius ratio,and lo-cation of bonding sites).This work offers new insights into the underlying mechanism of 2D-to-3D geometric transformation in ribbon-type structures formed by compressive buckling.
基金financially supported by the National Key R&D Program of China(Nos.2021YFC1910504 and 2024YFC3907701)the National Energy-Saving and Low-Carbon Materials Production and Application Demonstration Platform Program(No.TC220H06N)+2 种基金the Fundamental Research Funds for the Central Universities(No.FRF-EYIT-23-07)the National Natural Science Foundation of China(No.52204412)Beijing Natural Science Foundation(No.2242046)
文摘Transition metal-doped CeO_(2)catalysts exhibit great potentials for the selective catalytic reduction(SCR)of nitrogen oxide(NOx)with NH_(3)(NH_(3)-SCR).However,traditional research mainly relies on a lot of experiments to find out effective catalysts,which wastes a lot of time and resources.Screening out effective CeO_(2)-based catalysts for low-temperature NH_(3)-SCR via density functional theory(DFT)calculations is crucial for the rational design and synthesis of efficient catalysts.Herein,transition metal(M=Co,Cr,Cu,Fe,Mn,Mo,Nb,Ni,Ta,Ti,V,and W)-doped CeO_(2)catalysts were screened out via accelerated DFT calculations for NH_(3)-SCR of nitric-oxide(NO)using three theoretical terms;(i)an adsorption energy of NH_(3),(ii)an adsorption energy of NO,and(iii)the reaction energies between NO with O_(2)and lattice oxygen.The theoretically predicted trend in catalytic performance is as follows:CeO_(2)-Mn,-Cu,-Mo>CeO_(2)-Fe,-Co,-Ni,-V,-Cr>CeO_(2)-W,-Ti>CeO_(2)-Nb,-Ta.The theoretical prediction was well verified via experimental NH_(3)-SCR activity of NO at low temperatures(90–300℃),demonstrating CeO_(2)-Mo as efficient NH_(3)-SCR catalyst across a broad temperature range.Temperature-programmed desorption of NH_(3)and in situ diffuse reflectance infrared Fourier transforms spectroscopy further indicated that metal doping significantly enhanced the NH_(3)adsorption capacity and strength of CeO_(2)in the medium-to low-temperature range.Consequently,accelerated DFT calculations provide a useful tool with great potentials for predicting the catalytic performance.
基金funded by the India-Brazil bilateral co-operation Project:INT/BRAZIL/P-02/2013by Indian Statistical Institute,Geoscience Institute of São Paulo University,Brazil and Department of Geology,University of Calcutta.M.Hueck thanks FAPESP for a post-doctoral fellowship(grant 2019/06838-2).
文摘The Southern Granulite Terrane(Dharwar Craton),South India,is a key unit for understanding the origin of charnockite.New U-Pb and Lu-Hf analyses in zircon crys-tals from 16 samples representing a wide variety of litho-types from the quarries in Kabbaldurga reveal a complex geological history in the Archean and early Paleoprotero-zoic.Magmatic protoliths predominantly record Paleoar-chean ages between 3.4 and 3.2 Ga.Combined U-Pb and Lu-Hf signatures indicate a history of recurrent crustal anatexis,juvenile magmatic input,and felsic injections.Mesoarchaean magmatic charnockites were generated mainly from hornblende-dehydration melting of Paleoar-chaean mafic rocks.In addition,Peninsular Gneissic Com-plex of the Dharwar Craton,commonly described as TTG suites,are likely generated by melting of hydrated basalt.The new data are consistent with the idea of a convecting magmatic cycle and also support the proposal that the southern Dharwar Craton comprises a tilted cross-sec-tion through the Archaean crust.Paleoproterozoic high-temperature event is documented here as a complex unit involving juvenile mafic magmatism,granulite facies imprints and crustal anatexis as well as felsic injections,occurring within a short time period around 2.5 Ga.
