The graded density impactor(GDI)dynamic loading technique is crucial for acquiring the dynamic physical property parameters of materials used in weapons.The accuracy and timeliness of GDI structural design are key to ...The graded density impactor(GDI)dynamic loading technique is crucial for acquiring the dynamic physical property parameters of materials used in weapons.The accuracy and timeliness of GDI structural design are key to achieving controllable stress-strain rate loading.In this study,we have,for the first time,combined one-dimensional fluid computational software with machine learning methods.We first elucidated the mechanisms by which GDI structures control stress and strain rates.Subsequently,we constructed a machine learning model to create a structure-property response surface.The results show that altering the loading velocity and interlayer thickness has a pronounced regulatory effect on stress and strain rates.In contrast,the impedance distribution index and target thickness have less significant effects on stress regulation,although there is a matching relationship between target thickness and interlayer thickness.Compared with traditional design methods,the machine learning approach offers a10^(4)—10^(5)times increase in efficiency and the potential to achieve a global optimum,holding promise for guiding the design of GDI.展开更多
Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and ev...Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and even a chaotic or hyperchaotic system,the response network is complex system coupled by N nodes,and every node is showed by the approximately linear part of the drive system.Only controlling any one node of the response network by designed controller can achieve the projective synchronization.Some numerical examples were employed to verify the effectiveness and correctness of the designed controller.展开更多
The impact of extreme temperatures on the health of individuals in different organizations remains uncertain.We employed stratified analyses to examine the impacts of summer(April-September)daily maximum temperatures ...The impact of extreme temperatures on the health of individuals in different organizations remains uncertain.We employed stratified analyses to examine the impacts of summer(April-September)daily maximum temperatures and winter(October-March)daily minimum temperatures on blood pressure and lipid profiles across government staff,com-pany employees,and researchers.We examined 209,477 physical examination records from a physical examination center in the First Affiliated Hospital of USTC from 2017 to 2021.Employing a segmented regression model within the frame-work of generalized linear regression(GLM),we examined the causal impact of extreme temperatures on health outcomes.Additionally,sensitivity analyses were conducted via distributed lag nonlinear models(DLNMs),with a focus on ob-serving the long-term effects over a period of 21 days.Our findings indicate that government staff face increased health risks during extremely low temperatures,regardless of the season.Compared with participants experiencing median tem-peratures,government staff exposed to extremely low temperatures(below the 10th percentile,below 24℃)in the sum-mer presented maximum increases of 2.32 mmHg(95%CI:1.542-3.098)in diastolic blood pressure and 6.481 mmHg(95%CI:5.368-7.594)in systolic blood pressure.In winter,government staff exposed to temperatures below the 10th per-centile(below 1℃)demonstrated maximum increases of 0.278 mmol/L(95%CI:0.210-0.346)in total cholesterol,0.153 mmol/L(95%CI:0.032-0.274)in triglycerides,and 0.077 mmol/L(95%CI:0.192-0.134)in low-density lipoprotein.Conversely,warm winters benefit company employees,whereas researchers exhibit lower sensitivity to temperature changes in winter.The maximum temperatures in summer and minimum temperatures in winter had greater impacts on in-dividuals.Small temperature fluctuations impact health more than large changes do.Notably,both the maximum and min-imum temperatures were better predictors of health outcomes than the daily average temperature was.Blood pressure con-sistently displayed significant associations with temperature across all three groups,with extremely low temperatures in-creasing the risk and extremely high temperatures reducing it.However,the relationship between temperature and blood lipids is complex.展开更多
The abnormal metabolic activity of the tumor can increase the oxygen consumption in tumor cells,and the poor blood perfusion often happens in tumor regions as well,which are the main reasons that result in a hypoxic s...The abnormal metabolic activity of the tumor can increase the oxygen consumption in tumor cells,and the poor blood perfusion often happens in tumor regions as well,which are the main reasons that result in a hypoxic situation in the tumor.A fluorescence probe,AQD,with selective response toward hypoxia was designed for the detection of hypoxic tumor cells,which was obtained by the covalent connection of a large planar conjugated fluorophore with good fluorescence stability and a N,N-dimethylaniline moiety via the azo bond.The introduction of the azo bond in AQD caused significant fluorescence emission quenching,and the probe was reduced under hypoxic conditions to release the fluorophore via breaking the azo bond,resulting in the gradual recovery of fluorescence emission.Probe AQD exhibited a remarkable fluorescence response in hypoxic conditions,high selectivity,and good biocompatibility,which was successfully used for the imaging of hypoxic tumor cells and realized the detection of hypoxic A549 cells.展开更多
The work takes a new liquid-cooling plate in a power battery with pin fins inside the channel as the object.A mathematical model is established via the central composite design of the response surface to study the rel...The work takes a new liquid-cooling plate in a power battery with pin fins inside the channel as the object.A mathematical model is established via the central composite design of the response surface to study the relationships among the length,width,height,and spacing of pin fins;the maximum temperature and temperature difference of the battery module;and the pressure drop of the liquid-cooling plate.Model accuracy is verified via variance analysis.The new liquid-cooling plate enables the power battery to work within an optimal temperature range.Appropriately increasing the length,width,and height and reducing the spacing of pin fins could reduce the temperature of the power battery module and improve the temperature uniformity.However,the pressure drop of the liquid-cooling plate increases.The structural parameters of the pin fins are optimized to minimize the maximum temperature and the temperature difference of the battery module as well as the pressure drop of the liquid-cooling plate.The errors between the values predicted and actual by the simulation test are 0.58%,4%,and 0.48%,respectively,which further verifies the model accuracy.The results reveal the influence of the structural parameters of the pin fins inside the liquid-cooling plate on its heat dissipation performance and pressure drop characteristics.A theoretical basis is provided for the design of liquid-cooling plates in power batteries and the optimization of structural parameters.展开更多
Objective:Neuropathic pain(NP)is one of the most common forms of chronic pain,yet current treatment options are limited in effectiveness.Peripheral nerve injury activates spinal microglia,altering their inflammatory r...Objective:Neuropathic pain(NP)is one of the most common forms of chronic pain,yet current treatment options are limited in effectiveness.Peripheral nerve injury activates spinal microglia,altering their inflammatory response and phagocytic functions,which contributes to the progression of NP.Most current research on NP focuses on microglial inflammation,with relatively little attention to their phagocytic function.Early growth response factor 2(EGR2)has been shown to regulate microglial phagocytosis,but its specific role in NP remains unclear.This study aims to investigate how EGR2 modulates microglial phagocytosis and its involvement in NP,with the goal of identifying potential therapeutic targets.Methods:Adult male Sprague-Dawley(SD)rats were used to establish a chronic constriction injury(CCI)model of the sciatic nerve.Pain behaviors were assessed on days 1,3,7,10,and 14 post-surgery to confirm successful model induction.The temporal and spatial expression of EGR2 in the spinal cord was examined using real-time quantitative PCR(RT-qPCR),Western blotting,and immunofluorescence staining.Adeno-associated virus(AAV)was used to overexpress EGR2 in the spinal cord,and behavioral assessments were performed to evaluate the effects of EGR2 modulation of NP.CCI and lipopolysaccharide(LPS)models were established in animals and microglial cell lines,respectively,and changes in phagocytic activity were measured using RT-qPCR and fluorescent latex bead uptake assays.After confirming the involvement of microglial phagocytosis in NP,AAV was used to overexpress EGR2 in both in vivo and in vitro models,and phagocytic activity was further evaluated.Finally,eukaryotic transcriptome sequencing was conducted to screen differentially expressed mRNAs,followed by Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analyses to identify potential downstream effectors of EGR2.Results:The CCI model successfully induced NP.Following CCI,EGR2 expression in the spinal cord was upregulated in parallel with NP development.Overexpression of EGR2 via spinal AAV injection enhanced microglial phagocytic activity and increased pain hypersensitivity in rats.Both animal and cellular models showed that CCI or LPS stimulation enhanced microglial phagocytosis,which was further amplified by EGR2 overexpression.Transcriptomic analysis of spinal cord tissues from CCI rats overexpressing EGR2 revealed upregulation of numerous genes associated with microglial phagocytosis and pain regulation.Among them,Lag3 emerged as a potential downstream target of EGR2.Conclusion:EGR2 contributes to the maintenance of NP by enhancing microglial phagocytosis in the spinal dorsal horn.展开更多
[Objective]Under the combined impact of climate change and urbanization,urban rainstorm flood disasters occur frequently,seriously restricting urban safety and sustainable development.Relying on traditional grey infra...[Objective]Under the combined impact of climate change and urbanization,urban rainstorm flood disasters occur frequently,seriously restricting urban safety and sustainable development.Relying on traditional grey infrastructure such as pipe networks for urban stormwater management is not enough to deal with urban rainstorm flood disasters under extreme rainfall events.The integration of green,grey and blue systems(GGB-integrated system)is gradually gaining recognition in the field of global flood prevention.It is necessary to further clarify the connotation,technical and engineering implementation strategies of the GGB-integrated system,to provide support for the resilient city construction.[Methods]Through literature retrieval and analysis,the relevant research and progress related to the layout optimization and joint scheduling optimization of the GGBintegrated system were systematically reviewed.In response to existing limitations and future engineering application requirements,key supporting technologies including the utilization of overground emergency storage spaces,safety protection of underground important infrastructure and multi-departmental collaboration,were proposed.A layout optimization framework and a joint scheduling framework for the GGB-integrated system were also developed.[Results]Current research on layout optimization predominantly focuses on the integration of green system and grey system,with relatively fewer studies incorporating blue system infrastructure into the optimization process.Moreover,these studies tend to be on a smaller scale with simpler scenarios,which do not fully capture the complexity of real-world systems.Additionally,optimization objective tend to prioritize environmental and economic goals,while social and ecological factors are less frequently considered.Current research on joint scheduling optimization is often limited to small-scale plots,with insufficient attention paid to the entire system.There is a deficiency in method for real-time,automated determination of optimal control strategies for combinations of multiple system facilities based on actual rainfall-runoff processes.Additionally,the application of emergency facilities during extreme conditions is not sufficiently addressed.Furthermore,both layout optimization and joint scheduling optimization lack consideration of the mute feed effect of flood and waterlogging in urban,watershed and regional scales.[Conclusion]Future research needs to improve the theoretical framework for layout optimization and joint scheduling optimization of GGB-integrated system.Through the comprehensive application of the Internet of things,artificial intelligence,coupling model development,multi-scale analysis,multi-scenario simulation,and the establishment of multi-departmental collaboration mechanisms,it can enhance the flood resilience of urban areas in response to rainfall events of varying intensities,particularly extreme rainfall events.展开更多
Organic semiconductor materials have shown unique advantages in the development of optoelectronic devices due to their ease of preparation,low cost,lightweight,and flexibility.In this work,we explored the application ...Organic semiconductor materials have shown unique advantages in the development of optoelectronic devices due to their ease of preparation,low cost,lightweight,and flexibility.In this work,we explored the application of the organic semiconductor Y6-1O single crystal in photodetection devices.Firstly,Y6-1O single crystal material was prepared on a silicon substrate using solution droplet casting method.The optical properties of Y6-1O material were characterized by polarized optical microscopy,fluorescence spectroscopy,etc.,confirming its highly single crystalline performance and emission properties in the near-infrared region.Phototransistors based on Y6-1O materials with different thicknesses were then fabricated and tested.It was found that the devices exhibited good visible to near-infrared photoresponse,with the maximum photoresponse in the near-infrared region at 785 nm.The photocurrent on/off ratio reaches 10^(2),and photoresponsivity reaches 16 mA/W.It was also found that the spectral response of the device could be regulated by gate voltage as well as the material thickness,providing important conditions for optimizing the performance of near-infrared photodetectors.This study not only demonstrates the excellent performance of organic phototransistors based on Y6-1O single crystal material in near-infrared detection but also provides new ideas and directions for the future development of infrared detectors.展开更多
Objective To investigate whether 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucoside(TSG)ameliorated polycystic ovary syndrome(PCOS)-like characteristics by inhibiting inflammation.Methods PCOS models were established ...Objective To investigate whether 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucoside(TSG)ameliorated polycystic ovary syndrome(PCOS)-like characteristics by inhibiting inflammation.Methods PCOS models were established by injecting subcutaneously with dehydroepiandrosterone into female Sprague-Dawley rats,followed by receiving intraperitoneal injection of TSG.The granular cells(GCs)KGN were transfected with small interfering RNAs(si-NC and si-CYP19A1).The cells were preincubated with lipopolysaccharide(LPS)and then treated with or without TSG.The estrous cycle was monitored using vaginal exfoliated cells.The morphology of ovarian follicles was analyzed by H&E staining.ELISA was used to analyze estradiol(E2),testosterone(T),follicle stimulating hormone(FSH),luteinizing hormone(LH),IL-6,TNF-α,AGEs,CRP and Omentin-1 levels in serum.Immunohistochemistry was performed to analyze PCNA and CYP19A1 expressions in the GCs of ovaries.Tunel staining was executed to detect the apoptosis of GCs.Quantitative polymerase chain reaction(qPCR)and Western blot were implemented to measure the expression of CYP19A1 in the ovaries and transfected cells.qPCR was used to analyze the expression of IL-6 and TNF-αin the transfected cells treated with LPS and TSG.Results The estrous cycles were restored in TSG group.Compared with model group,the sinus follicles were reduced and corpus luteums were increased in TSG group.TSG group showed increased E2,and decreased T and LH,compared with model group.Pro-inflammatory factors(IL-6,TNF-α,CRP and AGEs)were decreased,and anti-inflammatory factor(Omentin-1)was increased in TSG group compared with those in model group.TSG could partially inhibit decrease of PNCA-positive GCs and increase of Tunel-positive GCs caused by PCOS.The CYP19A1 expression of GCs in TSG group was upregulated compared with model group.The expressions of IL-6 and TNFαin si-CYP19A1 cells were increased compared with si-NC cells.Compared with cells(si-NC and si-CYP19A1)treated without LPS,the expressions of IL-6 and TNF-αcells were increased,and the expression of CYP19A1 was downregulated in LPS-preincubated cells.Compared with cells treated with LPS,the expression of IL-6 and TNF-αwere decreased,and the expression of CYP19A1 was increased in cells treated with LPS and TSG.Compared with si-NC cells treated with LPS and TSG,the expressions of IL-6 and TNF-αcells were increased in the si-CYP19A1 cells treated with LPS and TSG.Conclusion TSG could alleviate PCOS-like characteristics by increasing the expression of CYP19A1 in GCs to inhibit inflammatory response.展开更多
The effects of pre-compression and pre-aging on the age-hardening response and microstructure of Mg-9.8Sn3.0 Zn(wt.%)alloy have been investigated via hardness test and advanced electron microscopy.The alloy subjected ...The effects of pre-compression and pre-aging on the age-hardening response and microstructure of Mg-9.8Sn3.0 Zn(wt.%)alloy have been investigated via hardness test and advanced electron microscopy.The alloy subjected to both pre-compression and pre-aging exhibits the most refined and densest distribution of precipitates upon aging at 200℃,leading to the superior age-hardening performance observed in the alloy.Comparatively,the alloy that underwent only pre-aging displayed a greater number density of precipitates than its counterpart that was neither pre-compressed nor pre-aged when both were aged to their peak conditions at 200℃,indicating an enhanced age-hardening response in the pre-aged alloy.The precipitates in these three peak-aged alloys consist of Mg_(2)Sn and MgZn_(2)phases.The reason why the pre-aged alloy has a higher number density of precipitates than the directly aged alloy is that MgZn_(2)phase formed during pre-aging can serve as heterogeneous nucleation site for the formation of Mg_(2)Sn.The reason why the pre compression and pre-aged alloy has the highest number density of precipitates is that Mg_(3)Sn and MgZn_(2)phases formed during pre-aging,alongside lattice defects introduced during pre-compression,collectively act as effective heterogeneous nucleation sites for the formation of Mg_(2)Sn during the subsequent aging at 200℃.展开更多
Multi-axle heavy-duty vehicles(MHVs)are essential for military equipment transport due to their safety and stability.However,braking dynamic responses between MHVs and pavement systems still remain underexplored,parti...Multi-axle heavy-duty vehicles(MHVs)are essential for military equipment transport due to their safety and stability.However,braking dynamic responses between MHVs and pavement systems still remain underexplored,particularly regarding their complex load transfer mechanisms.This paper develops an enhanced model of a multi-axle heavy-duty vehicle(MHV)coupled with the uneven and flexible pavement.An advanced coupling iterative method is proposed to solve the highly dimensional equations of the MHV-pavement coupled system.The proposed method was validated through experimental tests,with characteristic parameters of vertical accelerations showing relative errors between 0.42%and 11.80%.The coupling effect and influence mechanism of the braking process are investigated by characteristic parameters of the dynamic responses.Additionally,the influences of braking conditions and pavement parameters are analyzed in time and frequency domains in order to reveal the vibration mechanisms of the coupled system.Moreover,this study establishes a theoretical foundation for monitoring pavement health via vehicle-mounted acceleration signals,which is necessary in military transportation.展开更多
In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heati...In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heating time,microwave power,microwave heating time on the center temperature,moisture content,the chroma(C*),the total color difference(ΔE*),shape fidelity,hardness,and the total anthocyanin content of 3D printed raspberry preserves were analyzed by response surface method(RSM).The results showed that under combining with the two methods,infrared heating improved the fidelity and quality degradation of printed products,while microwave heating enhanced the efficiency of infrared heating.Infrared-microwave combination cooking could maintain relatively stable color appearance and shape of 3D printed raspberry preserves.The AHP–CRITIC hybrid weighting method combined with the response surface test to determine the comprehensive weights of the evaluation indicators optimized the process parameters,and the optimal process parameters were obtained:infrared heating temperature of 190℃,infrared heating time of 10 min and 30 s,microwave power of 300 W,and microwave heating time of 2 min and 6 s.The 3D printed raspberry cooking methods obtained under the optimal conditions seldom had color variation,porous structure,uniform texture,and high shape fidelity,which retained the characteristics of personalized manufacturing by 3D printing.This study could provide a reference for the postprocessing and quality control of 3D cooking methods.展开更多
Ground reinforcement is crucial for tunnel construction, especially in soft rock tunnels. Existing analytical models are inadequate for predicting the ground reaction curves (GRCs) for reinforced tunnels in strain-sof...Ground reinforcement is crucial for tunnel construction, especially in soft rock tunnels. Existing analytical models are inadequate for predicting the ground reaction curves (GRCs) for reinforced tunnels in strain-softening (SS) rock masses. This study proposes a novel analytical model to determine the GRCs of SS rock masses, incorporating ground reinforcement and intermediate principal stress (IPS). The SS constitutive model captures the progressive post- peak failure, while the elastic-brittle model simulates reinforced rock masses. Nine combined states are innovatively investigated to analyze plastic zone development in natural and reinforced regions. Each region is analyzed separately, and coupled through boundary conditions at interface. Comparison with three types of existing models indicates that these models overestimate reinforcement effects. The deformation prediction errors of single geological material models may exceed 75%. Furthermore, neglecting softening and residual zones in natural regions could lead to errors over 50%. Considering the IPS can effectively utilize the rock strength to reduce tunnel deformation by at least 30%, thereby saving on reinforcement and support costs. The computational results show a satisfactory agreement with the monitoring data from a model test and two tunnel projects. The proposed model may offer valuable insights into the design and construction of reinforced tunnel engineering.展开更多
The use of ultra-high molecular weight polyethylene(UHMWPE)composite in the design of lightweight protective equipment,has gained a lot of interest.However,there is an urgent need to understand the ballistic response ...The use of ultra-high molecular weight polyethylene(UHMWPE)composite in the design of lightweight protective equipment,has gained a lot of interest.However,there is an urgent need to understand the ballistic response mechanism and theoretical prediction model of performance.This paper explores the ballistic response mechanism of UHMWPE composite through experimental and simulation analyses.Then,a resistance-driven modeling method was proposed to establish a theoretical model for predicting the bulletproof performance.The ballistic response mechanism of UHMWPE composite encompassed three fundamental modes:local response,structural response,and coupled response.The occurrence ratio of these fundamental response modes during impact was dependent on the projectile velocity and laminate thickness.The bulletproof performance of laminate under different response modes was assessed based on the penetration depth of the projectile,the bulging height on the rear face of the laminate,the thickness of remaining sub-laminate,and residual velocity of the projectile.The absolute deviations of bulletproof performance indicator between theoretical value and experimental value were well within 11.13%,demonstrating that the established evaluation model possessed high degree of prediction accuracy.展开更多
To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistat...To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistatic pressure and structural residual deflection increase with increasing working pressure of the water mist nozzle.Specifically,the weakening rate of the initial peak overpressure ranges from 7.8%to 31.0%,the quasistatic pressure weakening rate ranges from 29.2%to 41.0%,and the weakening rate of the center of the plate residual deflection ranges from 10.8%to 34.4%under the various working pressures of the nozzles.To further explore the effect of water mist explosion suppression,a method for three-dimensional numerical simulations of water mist weakening the explosion shock wave is established to explore the explosion load characteristics of the compartment and the bulkhead response law.On the basis of the dimension analysis method,empirical formulas are derived to predict the residual deflection thickness in the center of the bulkheads.These findings provide the fundamental basis for the appli-cation of water mist in anti-explosive protection.展开更多
Full-component pyrolysis can process organic components and reduce cathode materials, making it a key focus in green recycling of lithium-ion batteries (LIBs). However, the leaching mechanism and kinetics of pyrolyzed...Full-component pyrolysis can process organic components and reduce cathode materials, making it a key focus in green recycling of lithium-ion batteries (LIBs). However, the leaching mechanism and kinetics of pyrolyzed black powder in organic acid systems remain unclear, with most research still at the laboratory stage. This study pioneers the exploration of the leaching behavior and reaction mechanism of valuable metal extraction from industrial-scale pyrolyzed black powder using citric acid. The effects of various leaching conditions on the extraction of metals were investigated by single factor experiments and response surface method. Under optimal conditions, the leaching efficiencies of Li, Ni, Co, and Mn all exceeded 97%. Kinetic analysis revealed that the leaching process was controlled by internal diffusion, with the apparent activation energies for Li, Ni, Co, and Mn being 17.89, 23.14, 20.27, and 15.21 kJ/mol, respectively. Additionally, residue characterization identified FePO4 formation as the primary inhibitor of iron dissolution.展开更多
The undercurrent research survey explores the roles of nonlocality and strain gradient size dependencies in nonlinear asymmetric buckling of shallow nanoscale arches having dissimilar end conditions through a numerica...The undercurrent research survey explores the roles of nonlocality and strain gradient size dependencies in nonlinear asymmetric buckling of shallow nanoscale arches having dissimilar end conditions through a numerical analysis.The arches,made from a functionally graded graphene nanofiller reinforced composite(FG-GNRC),are subjected to discretional radial concentrated loads along with converting of temperature.To account for the size dependencies,the exploration is carried out stemming from the nonlocal strain gradient theory(NSGT)in the sense of a quasi-2D parabolic shear flexible concept of curved beam.The material properties of the contemplated FG-GNRC sandwich are determined using the modified Halpin-Tsai micromechanics model.Subsequently,an extended isogeometric analysis(XIGA)is manipulated comprising insertion plus multiplication of knots to achieve the demanded lower continuity allocated to the integration between flexural and tangential reflexes.It is perceived that the both softening and stiffening concomitants assigned to the salient concentrated radial loads obtained by the developed NSGT-based XIGA diminish from the first upper limit to the second one,and then likewise from the first lower limit to the second one.Although,by becoming the upsurge in temperature higher,these softening and stiffening concomitants get more remarkable.展开更多
The afterburning of TNT and structural constraints in confined spaces significantly amplify the blast load,leading to severe structural damage. This study investigates the mechanisms underlying the enhanced dynamic re...The afterburning of TNT and structural constraints in confined spaces significantly amplify the blast load,leading to severe structural damage. This study investigates the mechanisms underlying the enhanced dynamic response of reinforced concrete blast doors with four-sided restraints in confined space. Explosion tests with TNT charges ranging from 0.15 kg to 0.4 kg were conducted in a confined space,capturing overpressure loads and the dynamic response of the blast door. An internal explosion model incorporating the afterburning effect was developed using LS-DYNA software and validated against experimental data. The results reveal that the TNT afterburning effect amplifies both the initial peak overpressure and the quasi-static overpressure, resulting in increased deformation of the blast door.Within the 0.15-0.4 kg charge range, the initial overpressure peak and quasi-static overpressure increased by an average of 1.79 times and 2.21 times, respectively. Additionally, the afterburning effect enhanced the blast door's deflection by 177%. Compared to open-space scenarios, the cumulative deflection of the blast door due to repeated shock wave impacts is significantly greater in confined spaces. Furthermore, the quasi-static pressure arising from the structural constraints sustains the blast door's deflection at a high level.展开更多
This study designs four types of liquid-filled cylindrical shell structures to investigate their protection characteristics against explosive shock waves and high-speed fragments.Bare charge and charge-driven prefabri...This study designs four types of liquid-filled cylindrical shell structures to investigate their protection characteristics against explosive shock waves and high-speed fragments.Bare charge and charge-driven prefabricated fragments are employed to examine the damage under blast shock waves and combined blast and fragments loading on various liquid-filled cylindrical shell structures.The test results are compared to numerical calculations and theoretical analysis for the structure's deformation,the liquid medium's movement,and the pressure waves'propagation characteristics under different liquid-filling methods.The results showed that the filling method influences the blast protection and the struc-ture's energy absorption performance.The external filling method reduces the structural deformation,and the internal filling method increases the damage effect.The gapped internal filling method improves the structure's energy absorption efficiency.The pressure wave loading on the liquid-filled cylindrical shell structure differs depending on filling methods.Explosive shock waves and high-speed fragments show a damage enhancement effect on the liquid-filled cylindrical shell structure,depending on the thickness of the internal liquid container layer.The specific impulse on the inner surface of the cylindrical shell positively correlates to the radial deformation of the cylindrical shell structure,and the external liquid layer limits the radial structural deformation.展开更多
Low collateral damage weapons achieve controlled personnel injury through the coupling of shock waves and particle swarms,where the particle swarms arise from the high-explosive dispersion of compacted metal particle ...Low collateral damage weapons achieve controlled personnel injury through the coupling of shock waves and particle swarms,where the particle swarms arise from the high-explosive dispersion of compacted metal particle ring.To investigate the dynamic response of the human target under combined shock waves and particle swarms loading,a physical human surrogate torso model(HSTM)was developed,and the dynamic response test experiment was conducted under the combined loading.The effects of particle size on the loading parameters,the damage patterns of the ballistic plate and HSTM,and the dynamic response parameters of the HSTM with and without protection are mainly analyzed.Our findings revealed that particle swarms can effectively delay the shock wave attenuation,especially the best effect when the particle size was 0.28–0.45 mm.The ballistic plate mainly exhibited dense perforation of the outer fabric and impacted crater damage of ceramic plates,whereas the unprotected HSTM was mainly dominated by high-density and small-size ballistic cavity group damage.The peak values of the dynamic response parameters for the HSTM under combined loading were significantly larger than those under bare charge loading,with multiple peaks observed.Under unprotected conditions,the peak acceleration of skeletons and peak pressure of organs increased with the particle size.Under protected conditions,the particle size,the number of particles hit,and the fit of the ballistic plate to the HSTM together affected the dynamic response parameters of the HSTM.展开更多
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2021B0301030001)the National Key Research and Development Program of China(Grant No.2021YFB3802300)the Foundation of National Key Laboratory of Shock Wave and Detonation Physics(Grant No.JCKYS2022212004)。
文摘The graded density impactor(GDI)dynamic loading technique is crucial for acquiring the dynamic physical property parameters of materials used in weapons.The accuracy and timeliness of GDI structural design are key to achieving controllable stress-strain rate loading.In this study,we have,for the first time,combined one-dimensional fluid computational software with machine learning methods.We first elucidated the mechanisms by which GDI structures control stress and strain rates.Subsequently,we constructed a machine learning model to create a structure-property response surface.The results show that altering the loading velocity and interlayer thickness has a pronounced regulatory effect on stress and strain rates.In contrast,the impedance distribution index and target thickness have less significant effects on stress regulation,although there is a matching relationship between target thickness and interlayer thickness.Compared with traditional design methods,the machine learning approach offers a10^(4)—10^(5)times increase in efficiency and the potential to achieve a global optimum,holding promise for guiding the design of GDI.
基金Supported by the National Natural Science Foundation of China (11161027)。
文摘Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and even a chaotic or hyperchaotic system,the response network is complex system coupled by N nodes,and every node is showed by the approximately linear part of the drive system.Only controlling any one node of the response network by designed controller can achieve the projective synchronization.Some numerical examples were employed to verify the effectiveness and correctness of the designed controller.
基金supported by the National Natural Science Foundation of China(72072169)the Fundamental Re-search Funds for the Central Universities(YD2040002015).
文摘The impact of extreme temperatures on the health of individuals in different organizations remains uncertain.We employed stratified analyses to examine the impacts of summer(April-September)daily maximum temperatures and winter(October-March)daily minimum temperatures on blood pressure and lipid profiles across government staff,com-pany employees,and researchers.We examined 209,477 physical examination records from a physical examination center in the First Affiliated Hospital of USTC from 2017 to 2021.Employing a segmented regression model within the frame-work of generalized linear regression(GLM),we examined the causal impact of extreme temperatures on health outcomes.Additionally,sensitivity analyses were conducted via distributed lag nonlinear models(DLNMs),with a focus on ob-serving the long-term effects over a period of 21 days.Our findings indicate that government staff face increased health risks during extremely low temperatures,regardless of the season.Compared with participants experiencing median tem-peratures,government staff exposed to extremely low temperatures(below the 10th percentile,below 24℃)in the sum-mer presented maximum increases of 2.32 mmHg(95%CI:1.542-3.098)in diastolic blood pressure and 6.481 mmHg(95%CI:5.368-7.594)in systolic blood pressure.In winter,government staff exposed to temperatures below the 10th per-centile(below 1℃)demonstrated maximum increases of 0.278 mmol/L(95%CI:0.210-0.346)in total cholesterol,0.153 mmol/L(95%CI:0.032-0.274)in triglycerides,and 0.077 mmol/L(95%CI:0.192-0.134)in low-density lipoprotein.Conversely,warm winters benefit company employees,whereas researchers exhibit lower sensitivity to temperature changes in winter.The maximum temperatures in summer and minimum temperatures in winter had greater impacts on in-dividuals.Small temperature fluctuations impact health more than large changes do.Notably,both the maximum and min-imum temperatures were better predictors of health outcomes than the daily average temperature was.Blood pressure con-sistently displayed significant associations with temperature across all three groups,with extremely low temperatures in-creasing the risk and extremely high temperatures reducing it.However,the relationship between temperature and blood lipids is complex.
文摘The abnormal metabolic activity of the tumor can increase the oxygen consumption in tumor cells,and the poor blood perfusion often happens in tumor regions as well,which are the main reasons that result in a hypoxic situation in the tumor.A fluorescence probe,AQD,with selective response toward hypoxia was designed for the detection of hypoxic tumor cells,which was obtained by the covalent connection of a large planar conjugated fluorophore with good fluorescence stability and a N,N-dimethylaniline moiety via the azo bond.The introduction of the azo bond in AQD caused significant fluorescence emission quenching,and the probe was reduced under hypoxic conditions to release the fluorophore via breaking the azo bond,resulting in the gradual recovery of fluorescence emission.Probe AQD exhibited a remarkable fluorescence response in hypoxic conditions,high selectivity,and good biocompatibility,which was successfully used for the imaging of hypoxic tumor cells and realized the detection of hypoxic A549 cells.
基金supported by the Education and Teaching Research Project of Universities in Fujian Province(FBJY20230167).
文摘The work takes a new liquid-cooling plate in a power battery with pin fins inside the channel as the object.A mathematical model is established via the central composite design of the response surface to study the relationships among the length,width,height,and spacing of pin fins;the maximum temperature and temperature difference of the battery module;and the pressure drop of the liquid-cooling plate.Model accuracy is verified via variance analysis.The new liquid-cooling plate enables the power battery to work within an optimal temperature range.Appropriately increasing the length,width,and height and reducing the spacing of pin fins could reduce the temperature of the power battery module and improve the temperature uniformity.However,the pressure drop of the liquid-cooling plate increases.The structural parameters of the pin fins are optimized to minimize the maximum temperature and the temperature difference of the battery module as well as the pressure drop of the liquid-cooling plate.The errors between the values predicted and actual by the simulation test are 0.58%,4%,and 0.48%,respectively,which further verifies the model accuracy.The results reveal the influence of the structural parameters of the pin fins inside the liquid-cooling plate on its heat dissipation performance and pressure drop characteristics.A theoretical basis is provided for the design of liquid-cooling plates in power batteries and the optimization of structural parameters.
基金supported by the National Natural Science Foundation of China(82071249 and 81771207).
文摘Objective:Neuropathic pain(NP)is one of the most common forms of chronic pain,yet current treatment options are limited in effectiveness.Peripheral nerve injury activates spinal microglia,altering their inflammatory response and phagocytic functions,which contributes to the progression of NP.Most current research on NP focuses on microglial inflammation,with relatively little attention to their phagocytic function.Early growth response factor 2(EGR2)has been shown to regulate microglial phagocytosis,but its specific role in NP remains unclear.This study aims to investigate how EGR2 modulates microglial phagocytosis and its involvement in NP,with the goal of identifying potential therapeutic targets.Methods:Adult male Sprague-Dawley(SD)rats were used to establish a chronic constriction injury(CCI)model of the sciatic nerve.Pain behaviors were assessed on days 1,3,7,10,and 14 post-surgery to confirm successful model induction.The temporal and spatial expression of EGR2 in the spinal cord was examined using real-time quantitative PCR(RT-qPCR),Western blotting,and immunofluorescence staining.Adeno-associated virus(AAV)was used to overexpress EGR2 in the spinal cord,and behavioral assessments were performed to evaluate the effects of EGR2 modulation of NP.CCI and lipopolysaccharide(LPS)models were established in animals and microglial cell lines,respectively,and changes in phagocytic activity were measured using RT-qPCR and fluorescent latex bead uptake assays.After confirming the involvement of microglial phagocytosis in NP,AAV was used to overexpress EGR2 in both in vivo and in vitro models,and phagocytic activity was further evaluated.Finally,eukaryotic transcriptome sequencing was conducted to screen differentially expressed mRNAs,followed by Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analyses to identify potential downstream effectors of EGR2.Results:The CCI model successfully induced NP.Following CCI,EGR2 expression in the spinal cord was upregulated in parallel with NP development.Overexpression of EGR2 via spinal AAV injection enhanced microglial phagocytic activity and increased pain hypersensitivity in rats.Both animal and cellular models showed that CCI or LPS stimulation enhanced microglial phagocytosis,which was further amplified by EGR2 overexpression.Transcriptomic analysis of spinal cord tissues from CCI rats overexpressing EGR2 revealed upregulation of numerous genes associated with microglial phagocytosis and pain regulation.Among them,Lag3 emerged as a potential downstream target of EGR2.Conclusion:EGR2 contributes to the maintenance of NP by enhancing microglial phagocytosis in the spinal dorsal horn.
文摘[Objective]Under the combined impact of climate change and urbanization,urban rainstorm flood disasters occur frequently,seriously restricting urban safety and sustainable development.Relying on traditional grey infrastructure such as pipe networks for urban stormwater management is not enough to deal with urban rainstorm flood disasters under extreme rainfall events.The integration of green,grey and blue systems(GGB-integrated system)is gradually gaining recognition in the field of global flood prevention.It is necessary to further clarify the connotation,technical and engineering implementation strategies of the GGB-integrated system,to provide support for the resilient city construction.[Methods]Through literature retrieval and analysis,the relevant research and progress related to the layout optimization and joint scheduling optimization of the GGBintegrated system were systematically reviewed.In response to existing limitations and future engineering application requirements,key supporting technologies including the utilization of overground emergency storage spaces,safety protection of underground important infrastructure and multi-departmental collaboration,were proposed.A layout optimization framework and a joint scheduling framework for the GGB-integrated system were also developed.[Results]Current research on layout optimization predominantly focuses on the integration of green system and grey system,with relatively fewer studies incorporating blue system infrastructure into the optimization process.Moreover,these studies tend to be on a smaller scale with simpler scenarios,which do not fully capture the complexity of real-world systems.Additionally,optimization objective tend to prioritize environmental and economic goals,while social and ecological factors are less frequently considered.Current research on joint scheduling optimization is often limited to small-scale plots,with insufficient attention paid to the entire system.There is a deficiency in method for real-time,automated determination of optimal control strategies for combinations of multiple system facilities based on actual rainfall-runoff processes.Additionally,the application of emergency facilities during extreme conditions is not sufficiently addressed.Furthermore,both layout optimization and joint scheduling optimization lack consideration of the mute feed effect of flood and waterlogging in urban,watershed and regional scales.[Conclusion]Future research needs to improve the theoretical framework for layout optimization and joint scheduling optimization of GGB-integrated system.Through the comprehensive application of the Internet of things,artificial intelligence,coupling model development,multi-scale analysis,multi-scenario simulation,and the establishment of multi-departmental collaboration mechanisms,it can enhance the flood resilience of urban areas in response to rainfall events of varying intensities,particularly extreme rainfall events.
基金Supported by the National Key Research and Development Program of China(2021YFB2012601)National Natural Science Foundation of China(12204109)+1 种基金Science and Technology Innovation Plan of Shanghai Science and Technology Commission(21JC1400200)Higher Education Indus⁃try Support Program of Gansu Province(2022CYZC-06)。
文摘Organic semiconductor materials have shown unique advantages in the development of optoelectronic devices due to their ease of preparation,low cost,lightweight,and flexibility.In this work,we explored the application of the organic semiconductor Y6-1O single crystal in photodetection devices.Firstly,Y6-1O single crystal material was prepared on a silicon substrate using solution droplet casting method.The optical properties of Y6-1O material were characterized by polarized optical microscopy,fluorescence spectroscopy,etc.,confirming its highly single crystalline performance and emission properties in the near-infrared region.Phototransistors based on Y6-1O materials with different thicknesses were then fabricated and tested.It was found that the devices exhibited good visible to near-infrared photoresponse,with the maximum photoresponse in the near-infrared region at 785 nm.The photocurrent on/off ratio reaches 10^(2),and photoresponsivity reaches 16 mA/W.It was also found that the spectral response of the device could be regulated by gate voltage as well as the material thickness,providing important conditions for optimizing the performance of near-infrared photodetectors.This study not only demonstrates the excellent performance of organic phototransistors based on Y6-1O single crystal material in near-infrared detection but also provides new ideas and directions for the future development of infrared detectors.
文摘Objective To investigate whether 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucoside(TSG)ameliorated polycystic ovary syndrome(PCOS)-like characteristics by inhibiting inflammation.Methods PCOS models were established by injecting subcutaneously with dehydroepiandrosterone into female Sprague-Dawley rats,followed by receiving intraperitoneal injection of TSG.The granular cells(GCs)KGN were transfected with small interfering RNAs(si-NC and si-CYP19A1).The cells were preincubated with lipopolysaccharide(LPS)and then treated with or without TSG.The estrous cycle was monitored using vaginal exfoliated cells.The morphology of ovarian follicles was analyzed by H&E staining.ELISA was used to analyze estradiol(E2),testosterone(T),follicle stimulating hormone(FSH),luteinizing hormone(LH),IL-6,TNF-α,AGEs,CRP and Omentin-1 levels in serum.Immunohistochemistry was performed to analyze PCNA and CYP19A1 expressions in the GCs of ovaries.Tunel staining was executed to detect the apoptosis of GCs.Quantitative polymerase chain reaction(qPCR)and Western blot were implemented to measure the expression of CYP19A1 in the ovaries and transfected cells.qPCR was used to analyze the expression of IL-6 and TNF-αin the transfected cells treated with LPS and TSG.Results The estrous cycles were restored in TSG group.Compared with model group,the sinus follicles were reduced and corpus luteums were increased in TSG group.TSG group showed increased E2,and decreased T and LH,compared with model group.Pro-inflammatory factors(IL-6,TNF-α,CRP and AGEs)were decreased,and anti-inflammatory factor(Omentin-1)was increased in TSG group compared with those in model group.TSG could partially inhibit decrease of PNCA-positive GCs and increase of Tunel-positive GCs caused by PCOS.The CYP19A1 expression of GCs in TSG group was upregulated compared with model group.The expressions of IL-6 and TNFαin si-CYP19A1 cells were increased compared with si-NC cells.Compared with cells(si-NC and si-CYP19A1)treated without LPS,the expressions of IL-6 and TNF-αcells were increased,and the expression of CYP19A1 was downregulated in LPS-preincubated cells.Compared with cells treated with LPS,the expression of IL-6 and TNF-αwere decreased,and the expression of CYP19A1 was increased in cells treated with LPS and TSG.Compared with si-NC cells treated with LPS and TSG,the expressions of IL-6 and TNF-αcells were increased in the si-CYP19A1 cells treated with LPS and TSG.Conclusion TSG could alleviate PCOS-like characteristics by increasing the expression of CYP19A1 in GCs to inhibit inflammatory response.
基金Project(52101167)supported by the National Natural Science Foundation of ChinaProject(2022JJ40604)supported by the Natural Science Foundation of Hunan Province,ChinaProject(2022ZZTS0538)supported by the Postgraduate Research Innovation Project of Central South University,China。
文摘The effects of pre-compression and pre-aging on the age-hardening response and microstructure of Mg-9.8Sn3.0 Zn(wt.%)alloy have been investigated via hardness test and advanced electron microscopy.The alloy subjected to both pre-compression and pre-aging exhibits the most refined and densest distribution of precipitates upon aging at 200℃,leading to the superior age-hardening performance observed in the alloy.Comparatively,the alloy that underwent only pre-aging displayed a greater number density of precipitates than its counterpart that was neither pre-compressed nor pre-aged when both were aged to their peak conditions at 200℃,indicating an enhanced age-hardening response in the pre-aged alloy.The precipitates in these three peak-aged alloys consist of Mg_(2)Sn and MgZn_(2)phases.The reason why the pre-aged alloy has a higher number density of precipitates than the directly aged alloy is that MgZn_(2)phase formed during pre-aging can serve as heterogeneous nucleation site for the formation of Mg_(2)Sn.The reason why the pre compression and pre-aged alloy has the highest number density of precipitates is that Mg_(3)Sn and MgZn_(2)phases formed during pre-aging,alongside lattice defects introduced during pre-compression,collectively act as effective heterogeneous nucleation sites for the formation of Mg_(2)Sn during the subsequent aging at 200℃.
基金National Defense Basic Scientific Research Program of China(Grant No.JCKY2021602B030).
文摘Multi-axle heavy-duty vehicles(MHVs)are essential for military equipment transport due to their safety and stability.However,braking dynamic responses between MHVs and pavement systems still remain underexplored,particularly regarding their complex load transfer mechanisms.This paper develops an enhanced model of a multi-axle heavy-duty vehicle(MHV)coupled with the uneven and flexible pavement.An advanced coupling iterative method is proposed to solve the highly dimensional equations of the MHV-pavement coupled system.The proposed method was validated through experimental tests,with characteristic parameters of vertical accelerations showing relative errors between 0.42%and 11.80%.The coupling effect and influence mechanism of the braking process are investigated by characteristic parameters of the dynamic responses.Additionally,the influences of braking conditions and pavement parameters are analyzed in time and frequency domains in order to reveal the vibration mechanisms of the coupled system.Moreover,this study establishes a theoretical foundation for monitoring pavement health via vehicle-mounted acceleration signals,which is necessary in military transportation.
基金Supported by the National Natural Science Foundation of China(32072352)。
文摘In order to improve the quality of 3D printed raspberry preserves after post-processing,microwave ovens combining infrared and microwave methods were utilized.The effects of infrared heating temperature,infrared heating time,microwave power,microwave heating time on the center temperature,moisture content,the chroma(C*),the total color difference(ΔE*),shape fidelity,hardness,and the total anthocyanin content of 3D printed raspberry preserves were analyzed by response surface method(RSM).The results showed that under combining with the two methods,infrared heating improved the fidelity and quality degradation of printed products,while microwave heating enhanced the efficiency of infrared heating.Infrared-microwave combination cooking could maintain relatively stable color appearance and shape of 3D printed raspberry preserves.The AHP–CRITIC hybrid weighting method combined with the response surface test to determine the comprehensive weights of the evaluation indicators optimized the process parameters,and the optimal process parameters were obtained:infrared heating temperature of 190℃,infrared heating time of 10 min and 30 s,microwave power of 300 W,and microwave heating time of 2 min and 6 s.The 3D printed raspberry cooking methods obtained under the optimal conditions seldom had color variation,porous structure,uniform texture,and high shape fidelity,which retained the characteristics of personalized manufacturing by 3D printing.This study could provide a reference for the postprocessing and quality control of 3D cooking methods.
基金Projects(52208382, 52278387, 51738002) supported by the National Natural Science Foundation of ChinaProject(2022YJS072) supported by the Fundamental Research Funds for the Central Universities,China。
文摘Ground reinforcement is crucial for tunnel construction, especially in soft rock tunnels. Existing analytical models are inadequate for predicting the ground reaction curves (GRCs) for reinforced tunnels in strain-softening (SS) rock masses. This study proposes a novel analytical model to determine the GRCs of SS rock masses, incorporating ground reinforcement and intermediate principal stress (IPS). The SS constitutive model captures the progressive post- peak failure, while the elastic-brittle model simulates reinforced rock masses. Nine combined states are innovatively investigated to analyze plastic zone development in natural and reinforced regions. Each region is analyzed separately, and coupled through boundary conditions at interface. Comparison with three types of existing models indicates that these models overestimate reinforcement effects. The deformation prediction errors of single geological material models may exceed 75%. Furthermore, neglecting softening and residual zones in natural regions could lead to errors over 50%. Considering the IPS can effectively utilize the rock strength to reduce tunnel deformation by at least 30%, thereby saving on reinforcement and support costs. The computational results show a satisfactory agreement with the monitoring data from a model test and two tunnel projects. The proposed model may offer valuable insights into the design and construction of reinforced tunnel engineering.
基金supported by the National Key Research and Development of China(Grant No.2022YFB4601901)the National Natural Science Foundation of China(Grant No.12122202)。
文摘The use of ultra-high molecular weight polyethylene(UHMWPE)composite in the design of lightweight protective equipment,has gained a lot of interest.However,there is an urgent need to understand the ballistic response mechanism and theoretical prediction model of performance.This paper explores the ballistic response mechanism of UHMWPE composite through experimental and simulation analyses.Then,a resistance-driven modeling method was proposed to establish a theoretical model for predicting the bulletproof performance.The ballistic response mechanism of UHMWPE composite encompassed three fundamental modes:local response,structural response,and coupled response.The occurrence ratio of these fundamental response modes during impact was dependent on the projectile velocity and laminate thickness.The bulletproof performance of laminate under different response modes was assessed based on the penetration depth of the projectile,the bulging height on the rear face of the laminate,the thickness of remaining sub-laminate,and residual velocity of the projectile.The absolute deviations of bulletproof performance indicator between theoretical value and experimental value were well within 11.13%,demonstrating that the established evaluation model possessed high degree of prediction accuracy.
基金supported by the National Natural Science Foundation of China(grant numbers:52201334)sup-ported by National Key Laboratory of Ship Structural Safety(grant numbers:Naklas2024-KF015-s).
文摘To investigate the explosion load characteristics and structural response law in a water mist environment in a cabin,explosion experiments are carried out.The weakening rates of the initial peak overpressure,quasistatic pressure and structural residual deflection increase with increasing working pressure of the water mist nozzle.Specifically,the weakening rate of the initial peak overpressure ranges from 7.8%to 31.0%,the quasistatic pressure weakening rate ranges from 29.2%to 41.0%,and the weakening rate of the center of the plate residual deflection ranges from 10.8%to 34.4%under the various working pressures of the nozzles.To further explore the effect of water mist explosion suppression,a method for three-dimensional numerical simulations of water mist weakening the explosion shock wave is established to explore the explosion load characteristics of the compartment and the bulkhead response law.On the basis of the dimension analysis method,empirical formulas are derived to predict the residual deflection thickness in the center of the bulkheads.These findings provide the fundamental basis for the appli-cation of water mist in anti-explosive protection.
基金Projects(52174269, 52374293) supported by the National Natural Science Foundation of ChinaProjects(2024CK1009, 2022RC1123) supported by the Science and Technology Innovation Program of Hunan Province,China。
文摘Full-component pyrolysis can process organic components and reduce cathode materials, making it a key focus in green recycling of lithium-ion batteries (LIBs). However, the leaching mechanism and kinetics of pyrolyzed black powder in organic acid systems remain unclear, with most research still at the laboratory stage. This study pioneers the exploration of the leaching behavior and reaction mechanism of valuable metal extraction from industrial-scale pyrolyzed black powder using citric acid. The effects of various leaching conditions on the extraction of metals were investigated by single factor experiments and response surface method. Under optimal conditions, the leaching efficiencies of Li, Ni, Co, and Mn all exceeded 97%. Kinetic analysis revealed that the leaching process was controlled by internal diffusion, with the apparent activation energies for Li, Ni, Co, and Mn being 17.89, 23.14, 20.27, and 15.21 kJ/mol, respectively. Additionally, residue characterization identified FePO4 formation as the primary inhibitor of iron dissolution.
基金supported by projects VEGA 1/0307/23 and APVV-23-0204 of Scientific Grant Agency of the Ministry of Education,Research,Development and Youth of the Slovak Republic.
文摘The undercurrent research survey explores the roles of nonlocality and strain gradient size dependencies in nonlinear asymmetric buckling of shallow nanoscale arches having dissimilar end conditions through a numerical analysis.The arches,made from a functionally graded graphene nanofiller reinforced composite(FG-GNRC),are subjected to discretional radial concentrated loads along with converting of temperature.To account for the size dependencies,the exploration is carried out stemming from the nonlocal strain gradient theory(NSGT)in the sense of a quasi-2D parabolic shear flexible concept of curved beam.The material properties of the contemplated FG-GNRC sandwich are determined using the modified Halpin-Tsai micromechanics model.Subsequently,an extended isogeometric analysis(XIGA)is manipulated comprising insertion plus multiplication of knots to achieve the demanded lower continuity allocated to the integration between flexural and tangential reflexes.It is perceived that the both softening and stiffening concomitants assigned to the salient concentrated radial loads obtained by the developed NSGT-based XIGA diminish from the first upper limit to the second one,and then likewise from the first lower limit to the second one.Although,by becoming the upsurge in temperature higher,these softening and stiffening concomitants get more remarkable.
基金financially supported by the National Natural Science Foundation of China (Grant No. 52278504)the Natural Science Foundation of Jiangsu Province (Grant No. BK20220141)。
文摘The afterburning of TNT and structural constraints in confined spaces significantly amplify the blast load,leading to severe structural damage. This study investigates the mechanisms underlying the enhanced dynamic response of reinforced concrete blast doors with four-sided restraints in confined space. Explosion tests with TNT charges ranging from 0.15 kg to 0.4 kg were conducted in a confined space,capturing overpressure loads and the dynamic response of the blast door. An internal explosion model incorporating the afterburning effect was developed using LS-DYNA software and validated against experimental data. The results reveal that the TNT afterburning effect amplifies both the initial peak overpressure and the quasi-static overpressure, resulting in increased deformation of the blast door.Within the 0.15-0.4 kg charge range, the initial overpressure peak and quasi-static overpressure increased by an average of 1.79 times and 2.21 times, respectively. Additionally, the afterburning effect enhanced the blast door's deflection by 177%. Compared to open-space scenarios, the cumulative deflection of the blast door due to repeated shock wave impacts is significantly greater in confined spaces. Furthermore, the quasi-static pressure arising from the structural constraints sustains the blast door's deflection at a high level.
基金the National Natural Science Foundation of China(Grant Nos.52371342,52271338,52101378 and 51979277)。
文摘This study designs four types of liquid-filled cylindrical shell structures to investigate their protection characteristics against explosive shock waves and high-speed fragments.Bare charge and charge-driven prefabricated fragments are employed to examine the damage under blast shock waves and combined blast and fragments loading on various liquid-filled cylindrical shell structures.The test results are compared to numerical calculations and theoretical analysis for the structure's deformation,the liquid medium's movement,and the pressure waves'propagation characteristics under different liquid-filling methods.The results showed that the filling method influences the blast protection and the struc-ture's energy absorption performance.The external filling method reduces the structural deformation,and the internal filling method increases the damage effect.The gapped internal filling method improves the structure's energy absorption efficiency.The pressure wave loading on the liquid-filled cylindrical shell structure differs depending on filling methods.Explosive shock waves and high-speed fragments show a damage enhancement effect on the liquid-filled cylindrical shell structure,depending on the thickness of the internal liquid container layer.The specific impulse on the inner surface of the cylindrical shell positively correlates to the radial deformation of the cylindrical shell structure,and the external liquid layer limits the radial structural deformation.
文摘Low collateral damage weapons achieve controlled personnel injury through the coupling of shock waves and particle swarms,where the particle swarms arise from the high-explosive dispersion of compacted metal particle ring.To investigate the dynamic response of the human target under combined shock waves and particle swarms loading,a physical human surrogate torso model(HSTM)was developed,and the dynamic response test experiment was conducted under the combined loading.The effects of particle size on the loading parameters,the damage patterns of the ballistic plate and HSTM,and the dynamic response parameters of the HSTM with and without protection are mainly analyzed.Our findings revealed that particle swarms can effectively delay the shock wave attenuation,especially the best effect when the particle size was 0.28–0.45 mm.The ballistic plate mainly exhibited dense perforation of the outer fabric and impacted crater damage of ceramic plates,whereas the unprotected HSTM was mainly dominated by high-density and small-size ballistic cavity group damage.The peak values of the dynamic response parameters for the HSTM under combined loading were significantly larger than those under bare charge loading,with multiple peaks observed.Under unprotected conditions,the peak acceleration of skeletons and peak pressure of organs increased with the particle size.Under protected conditions,the particle size,the number of particles hit,and the fit of the ballistic plate to the HSTM together affected the dynamic response parameters of the HSTM.
