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The impact of climate warming on soil microbes has been well documented, with studies revealing its effects on diversity, community structure and network dynamics. However, the consistency of soil microbial community assembly, particularly in response to diverse plant root exudates under varying temperature conditions, remains an unresolved issue. To address this issue, we employed a growth chamber to integrate temperature and root exudates in a controlled experiment to examine the response of soil bacteria, fungi, and protists. Our findings revealed that temperature independently regulated microbial diversity, with distinct patterns observed among bacteria, fungi, and protists. Both root exudates and temperature significantly influenced microbial community composition, yet interpretations of these factors varied among prokaryotes and eukaryotes. In addition to phototrophic bacteria and protists, as well as protistan consumers, root exudates determined to varying degrees the enrichment of other microbial functional guilds at specific temperatures. The effects of temperature and root exudates on microbial co-occurrence patterns were interdependent; root exudates primarily simplified the network at low and high temperatures, while responses to temperature varied between single and mixed exudate treatments. Moreover, temperature altered the composition of keystone species within the microbial network, while root exudates led to a decrease in their number. These results emphasize the substantial impact of plant root exudates on soil microbial community responses to temperature, underscoring the necessity for future climate change research to incorporate additional environmental variables. • Bacteria, fungi, and protists respond differently to root exudates and temperature. • Root exudates alter the regulation of temperature on microbial functional guilds. • Root exudates and temperature jointly determine the microbial co-occurrence pattern. • Root exudates reduce the number of keystone nodes in microbial networks. • Temperature changes the phylogeny of keystone nodes in microbial networks. [ABSTRACT FROM AUTHOR]

The theoretical as well as experimental investigations on the resonance frequency shift characteristic of a ferromagnetic plate in an inclined magnetic field are presented. A magnetic traction on the interface between a ferromagnetic material and the air is derived. An analytical model with the nonlinear law of magnetization is proposed for the field-dependent resonance frequency of a ferromagnetic plate. Model predictions show good correlation with the experimental data at different inclined angles. Both the theoretical and experimental investigations show that there exists a critical angle of the inclined field, below which the resonance frequency of the ferromagnetic plate will increase with the magnetic field, and above which the frequency will decrease with increasing the field. The critical angle predicted by the model, which is 86°, is exactly in the range revealed by experiments. Furthermore, the predictions show that the critical angle is sensitive to the length-to-thick ratio of the plate. [ABSTRACT FROM AUTHOR]

The mechanical behavior of fcc (face center cubic) metals and their alloys such as copper-based and aluminum-based materials changes obviously under high current density, but there is a lack of suitable constitutive model to describe the electroplastic behavior of these materials, which limits the accuracy of the mechanical response prediction in applications, such as electromagnetic launch. In this paper, a novel nonlinear constitutive model for electroplastic behavior under the high current density of fcc metals and their alloys is proposed. The model proposed is based on the theory of dislocation evolution, energy transfer theory and electron transport theory and takes into account the effects of high current density on dislocation density, strain rate and resistivity. Considering the evolution of forward and reverse dislocations caused by pulsed current, the relationship between the evolution rate of reverse dislocation and strain is established. Due to the sensitivity of the electroplastic effect to strain rate, the strain rate under electric current is obtained by combining the theory of dislocation thermal activation and energy transfer. According to the concept of thermal resistance and dislocation resistance, the relationship between resistance and current density is derived. The quantitative results demonstrate that this model can well capture the flow stress softening under high current density (>3000 A/mm2) and the transient hardening after current removal because of the consideration of a more suitable strain rate and dislocation evolution. The critical current density that has a significant effect on the strain rate and the current density corresponding to the subsection point of the resistivity are quantitatively obtained. Especially, it is shown that the evolution rate of the reverse dislocation decreases nonlinearly with the increase of strain after the current is removed. These results will be helpful to study the mechanical behavior of the rail during electromagnetic launch and further optimize the design of electromagnetic launch device. • A constitutive model of fcc metals and their alloys under the high current density is proposed. • The relationship between the evolution rate of reverse dislocation and strain is established. • The effect of current density on strain rate is included. • The proposed model can well describe the electroplastic behavior of fcc metals and their alloys under pulsed current. [ABSTRACT FROM AUTHOR]

Achieving higher and faster energy release processes is a major research goal for energetic materials (EMs). Typically, EMs enhance their overall performance by incorporating catalysts. The novel two-dimensional layered MXenes, such as Ti 3 C 2 T x , have shown significant potential as additives for ammonium perchlorate (AP). However, there is limited research on the impact of the exfoliation degree and high temperature oxidation of Ti 3 C 2 T x MXene catalyst on the pyrolysis and combustion of different types of EMs. In this study, ultrathin Ti 3 C 2 T x (U–Ti 3 C 2 T x) MXene with a high exfoliation degree of approximately 20–80 nm was obtained through hydrofluoric acid (HF) etching, dimethyl sulfoxide (DMSO)-assisted layer expansion and ultrasonic peeling. The catalytic performance of MXenes on the thermal decomposition of three types of EMs (dihydroxylammonium 5, 5′-bistetrazole-1, 1′-diolate (TKX-50), cyclotetramethylene tetranitroamine (HMX), and AP) was evaluated. Results showed that 4 wt% U–Ti 3 C 2 T x can reduce the decomposition peak of TKX-50 by 33.6 °C and decreases the high temperature decomposition (HTD) peak of AP by 45.5 °C, indicating superior catalytic performance compared to non-exfoliated Ti 3 C 2 T x MXene. However, it had insignificant effect on HMX. Surface chemical analysis, electrochemical characterization, thermal decomposition of gaseous products analysis and material studio simulation all confirmed that high exfoliation U–Ti 3 C 2 T x MXene exhibited better stability and electrical conductivity, facilitating the acceleration of the H+ transfer process and rapid gas release from EMs. Additionally, ignition tests demonstrated that high exfoliation U–Ti 3 C 2 T x could effectively participate in the ignition process of EMs. The characterization and thermal analysis of Ti 3 C 2 T x products after high temperature and oxidation treatment indicated that the catalytic activity is weakened due to high temperature crystal collapse and surface oxidation to TiO x metamorphism. This study provides new insights for the application of MXene catalysts in EMs. [ABSTRACT FROM AUTHOR]

• The loading history variable is established to record stress history variation. • An improved kinematic hardening rule is developed to simulate ratcheting effect. • A new plastic strain surface is proposed for the evolution of yield stress. • The proposed model can well describe the ratcheting during uniaxial loading. In this paper, an elastoplastic constitutive model is developed to describe the effect of loading history on the ratcheting. The loading history variable is introduced to record stress history variation during cyclic loading, such as equivalent peak stress and equivalent stress amplitude. Based on Ohno-Wang model, an improved kinematic hardening rule is proposed to simulate the ratcheting effect by establishing the nonlinear evolution equation of ratcheting parameter. A new memory evanescence term is introduced to the plastic strain range memory surface. The evanescence term is activated to describe the difference of yield stress evolution during ratcheting and strain-controlled cyclic loading as the plastic strain range radius exceeds a certain threshold. Compared with the experiments and existing models, the results show that the proposed model can better capture the ratcheting effect with loading history. [Display omitted] [ABSTRACT FROM AUTHOR]

• A transient multi-field coupling mathematical model based on finite element method is proposed. • The solution of the proposed model is based on three fundamentals laws. • The laws include Maxwell's equations, Fourier's law and elasticity theory. • The magneto-electro-thermo-mechanical response for conductors with extreme conditions is described. • The most vulnerable structural damage occurs at the initial section of the rail conductors. When the conductors are placed under powerful impulse current, high-velocity friction, strong time-dependent magnetic field, such as the operating conditions for the rails of an electromagnetic launcher, the response of the structure will be strongly influenced by the extraordinary environments. Few experimental tools are directly available to these operating conditions to evaluate the reliability and durability of the conductors. Therefore, a transient multi-field coupling mathematical model is proposed to study the magnetic field, thermal field and structure deformation and the coupling characteristics between them by solving the problems of transient magnetic diffusion, transient heat transfer, quasi-static elasticity and contact mechanics in conductors with finite element method. The model validation is then presented by comparison with the experimental results. It is shown that the proposed multi-field coupling model could better describe the magneto-electro-thermo -mechanical response because of the consideration of the effects of multi-field coupling (EMC) and the interface contact pressure caused by structural deformation. The multiphysics characteristics and the velocity skin effects closely related to the velocity can be correctly described with our model. Especially, the EMC increases the magnetic flux density of the whole conductor, lowers the temperature in the high-temperature region but increases the temperature for the low-temperature region, which will make the temperature distribution more uniform in the conductor. Moreover, the initial section of the conductors is the most vulnerable to damage in terms of the thermal field and structural deformation. These results will be significant to understand the multi-field coupling mathematical modelling process and to study the conductor with extreme operating conditions. [ABSTRACT FROM AUTHOR]

Protists, as the core component of the soil microbiome, may play an important role in forest succession by altering soil nutrient cycling and plant performance. However, knowledge of how protists change with plant succession is extremely limited. To illustrate protistan community dynamics following plant succession in subalpine natural and planted ecosystems, we used high-throughput sequencing to identify protists in rhizosphere and bulk soils at different successional stages, and the effects of soil abiotic and biotic factors on protists were analysed. Overall, the α-diversity and community composition of protists differed significantly between natural and planted ecosystems, but not between rhizosphere and bulk soils. Moving along the successional gradient, the richness and diversity of protists in rhizosphere and bulk soils of natural ecosystems, as well as the richness of functional taxa (i.e., consumers, parasites and phototrophs), gradually increased. In contrast, the richness of protists and functional taxa in the plantations was generally lowest in the old stands (75 years). The community composition of protists in rhizosphere and bulk soils of these two ecosystems varied significantly among successional stages, and their community composition variation was positively correlated with the time interval of successional stages, indicating that community dynamics exhibited directionality along successional gradients. Soil abiotic and biotic factors jointly regulate protistan α-diversity and community composition, and forest succession regulates functional taxa through multiple pathways. However, the key influencing factors and specific regulatory pathways are not consistent across different ecosystems, soil types and functional taxa. Therefore, our study has revealed that protistan community assembly was distinct along two separate successional gradients, indicating potential functional differences. These results provide a basis for the development of future forest management measures. • Natural succession increased the α-diversity of soil protists and their functional taxa, but plantation succession did not. • Protistan community composition varied significantly among successional stages. • Protistan community dynamics showed directionality along successional gradients. • The key factors affecting protists differ between natural and planted ecosystems, and between rhizosphere and bulk soils. [ABSTRACT FROM AUTHOR]

• The bump promotes the formation of hot spots and ignites the oblique detonation. • The wave structure changes the initiated mode of oblique detonation. • Theoretical shock polar analysis is used to determine the wave structures. • The developed boundary layer has great influence on the flow field characteristics. This paper studies the mechanism of oblique detonation wave (ODW) initiation induced by a blunt bump in the induction zone. The effects of geometric shapes and viscosity on the flow field characteristics are analyzed. Results demonstrate that the blunt bump promotes the formation of hot spots and the initiation of the oblique detonation wave. The interactive wave configuration at the front of the obstacle plays a vital role in the formation of the oblique detonation wave. The transition from the regular interaction to the Mach one results in the oblique detonation initiation. The viscous boundary layer influences the wave structures, the combustion characteristics, and thermodynamic parameters. Recirculation zone formed behind the streamline surface is smaller compared with ones formed behind circular and elliptic surfaces. [ABSTRACT FROM AUTHOR]

• Present a method to calculate the spatiotemporal deformation of tunnel. • Application in a mine exposes the time-dependent deformation of tunnel. • The method can warn instability of tunnel by discerning hot deformation islands. The three dimensional deformation and corresponding temporal evolution of surrounding rock is a key information for tunnel stability analysis and safety warning. To reconstruct the 3D deformation process of tunnel based on point cloud data by laser scanning, a semi-automatic method is presented to align the point cloud data of the tunnel surfaces at different stages. This method includes three steps: (i) initial alignment, splitting, denosing and merging of the tunnel surface's point clouds; (ii) coordinate transformation between the tunnel surface's point clouds according to the arch's geometric characteristics; and (iii) calculation and visualization of the tunnel surface's sequential deformation based on the multiscale model cloud comparison algorithm. The technical application of the time-dependent deformation analysis for an experimental tunnel in a mine indicated that this method can not only fully expose the evolution process of tunnel surrounding rock deformation, i.e., the spatial inhomogeneity, partitioning and temporal characteristics, but also can warn instability of tunnel by discerning hot deformation islands, i.e., zones with relatively large deformation. [ABSTRACT FROM AUTHOR]