To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requir...To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requires immediate investigation.In view of this phenomenon,the durability of unit lining concrete is predicted by analyzing three key indicators:carbonation depth,relative dynamic elastic modulus,and residual quality.This prediction is achieved by integrating the Entropy Weight Method,Grey theory life prediction model and BP artificial neural networks using data from tests and predictions of these indicators.Then,the Entropy Weight-Grey theory-BP Network Model is compared with other methods to analyze the predicted life.Finally,verify the sci-entificity of this model,and the optimum silica fume content of unit concrete lining is verified.The results showed,1)The addition of silica fume will accelerate the carbonization of unit concrete lining,and slow down the freeze-thaw cycle and sulfate erosion.2)The utilization of artificial neural networks is essential for enhancing the realism of the data,as it emphasizes the significance of silica fume content.3)Silica fume content of 10%results in the longest life and is the most suitable for lining construction.4)A comparison between single-factor and multi-factor predictions indicates that the multi-factor approach yields a longer maximum life.This improvement can be attributed to the inclusion of additional factors,such as freeze-thaw cycles and carbonation,which enhance the predicted life when employing these methods.In conclusion,the Entropy Weight-Grey Theory-BP Network life prediction Model is well-suited for tunnel lining in the alpine sulfate area of northwest China.展开更多
The intricate relationship between origami and mechanism underscores the fertile ground for innovation,which is particularly evident in the construction theory of thick-panel origami.Despite its potential,thick panel ...The intricate relationship between origami and mechanism underscores the fertile ground for innovation,which is particularly evident in the construction theory of thick-panel origami.Despite its potential,thick panel origami remains relatively unexplored in the context of single-loop metamorphic mechanisms.Drawing inspiration from thickpanel origami,particularly Miura origami,this study proposes a pioneering single-loop 6R multiple metamorphic mechanism.Through rigorous mathematical modeling(including the construction and resolution of the D-H closed-loop equation)and leveraging advanced analytical tools such as the screw theory and Lie theory,this study meticulously elucidates the planar,spherical,and Bennett motion branches of the mechanism.Furthermore,it delineates all the three bifurcation points between the motion branches,thereby providing a comprehensive understanding of the kinematic behavior of the mechanism.A metamorphic network can be constructed by applying several single-loop mechanisms to a symmetrical layout.Owing to its metamorphic properties,this network can act as a structural backbone for deployable antennas,aerospace shelters,and morphing wing units,thereby enabling a single mechanism to achieve multiple folding configurations.This paper not only introduces innovative metamorphic mechanisms but also suggests a promising method for uncovering and designing metamorphic mechanisms by developing new mechanisms from thick-panel origami.展开更多
The coupling effects among the flow field,temperature distribution and structural deformation in a turbine cannot be ignored,particularly during flight cycles when the turbine experiences varied operational states.Rel...The coupling effects among the flow field,temperature distribution and structural deformation in a turbine cannot be ignored,particularly during flight cycles when the turbine experiences varied operational states.Relying solely on steady-state solutions cannot predict the detrimental effects caused by hysteresis.Consequently,this paper employs a quasi-steady-state fluid-thermalstructure multidisciplinary coupling solution method,integrating transient solid heat conduction with steady-state flow field and static structural deformation solutions.After conducting a numerical simulation of a three-dimensional,five-stage,low-pressure turbine air system,the following conclusions are drawn:when boundary conditions attain high-power states through processes that are numerically identical but in opposite directions,slight variations in solid deformation significantly impact the flow field;when boundary conditions attain high-power states through processes that are directionally consistent but have different numerical values,the influence of the boundary condition change rate on the flow field surpasses that of solid deformation.In terms of turbine design parameters,a large difference in stage-reaction between adjacent stages at the lower radius of the turbine can lead to significant changes in the disc cavity flow field during flight cycles.The difference in the stage-reaction of 0.23 at 10%blade height in adjacent stages may induce severe gas ingress in the stator disc cavity.Thus,it is crucial to minimize this difference and to appropriately extend the duration of the deceleration phase to ensure the turbine's safe operation.展开更多
This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw ...This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw resistance and durability of recycled concrete samples under varying freeze-thaw cycles.The results indicate that an appropriate addition of SAP significantly enhances the freeze-thaw resistance of recycled concrete.After 200 freeze-thaw cycles,the RS0.6 sample retained good surface integrity,demonstrating the best performance.Compared to NAC,its mass loss decreased by 1.16%,the relative dynamic modulus improved by 7.01%,and the compressive strength loss rate decreased by 5.41%.Additionally,T2 spectrum analysis revealed that adding SAP optimized the pore structure of recycled concrete and mitigated pore development during freeze-thaw cycles.As the number of freeze-thaw cycles increased,the RS0.3 and RS0.6 samples demonstrated superior frost resistance compared to NAC.However,an excessive amount of SAP increased pore expansion during subsequent freeze-thaw cycles,ultimately weakening frost resistance.展开更多
Freeze–thaw(F–T)cycle-induced cracking in silty clays poses a significant risk to engineering stability.Although the individual addition of fly ash(FA)or sisal fiber(SF)provides partial solutions,their simultaneous ...Freeze–thaw(F–T)cycle-induced cracking in silty clays poses a significant risk to engineering stability.Although the individual addition of fly ash(FA)or sisal fiber(SF)provides partial solutions,their simultaneous application may result in a synergistic effect to compensate for their respective shortcomings.In this study,the effects of SF and FA on the mechanical properties,crack resistance,water retention,and erosion resistance of improved soil were systematically investigated through unconfined compressive strength(UCS)tests,crack evolution analysis,simulated rainfall erosion tests,and microscopic characterization(laser particle size analysis and nitrogen adsorption).The results reveal that the volumetric stability of FA particles significantly inhibits cracking in soil after F–T cycles.However,FA contributes only slightly to soil strength and erosion resistance.SF,on the other hand,plays a substantial role in increasing both soil strength and erosion resistance.The synergy between FA and SF results in the simultaneous increase in crack resistance,erosion resistance,and strength.FA improves the aggregate stability during F–T cycles,whereas SF reinforces the bonds between these aggregates.A comprehensive evaluation of the improved soil during F–T cycles using the entropy weight-TOPSIS method reveal that the combination of 10%FA+18 mm SF performed the best,achieving a 246%higher composite score than the unmodified soil did.With respect to this optimal combination,compared with the unmodified soil,the SF–FA-improved soil exhibits a 30%reduction in the average crack width,a 30%reduction in the erosion rate,and a 46%increase in strength.The findings of this study provide a scientific basis for the design of soil improvement in disaster mitigation engineering in seasonally frozen soil regions.展开更多
The solar cycle(SC),a phenomenon caused by the quasi-periodic regular activities in the Sun,occurs approximately every 11 years.Intense solar activity can disrupt the Earth’s ionosphere,affecting communication and na...The solar cycle(SC),a phenomenon caused by the quasi-periodic regular activities in the Sun,occurs approximately every 11 years.Intense solar activity can disrupt the Earth’s ionosphere,affecting communication and navigation systems.Consequently,accurately predicting the intensity of the SC holds great significance,but predicting the SC involves a long-term time series,and many existing time series forecasting methods have fallen short in terms of accuracy and efficiency.The Time-series Dense Encoder model is a deep learning solution tailored for long time series prediction.Based on a multi-layer perceptron structure,it outperforms the best previously existing models in accuracy,while being efficiently trainable on general datasets.We propose a method based on this model for SC forecasting.Using a trained model,we predict the test set from SC 19 to SC 25 with an average mean absolute percentage error of 32.02,root mean square error of 30.3,mean absolute error of 23.32,and R^(2)(coefficient of determination)of 0.76,outperforming other deep learning models in terms of accuracy and training efficiency on sunspot number datasets.Subsequently,we use it to predict the peaks of SC 25 and SC 26.For SC 25,the peak time has ended,but a stronger peak is predicted for SC 26,of 199.3,within a range of 170.8-221.9,projected to occur during April 2034.展开更多
Compared with traditional energy sources,wind power has a lower environmental impact.However,emissions are still generated across the life cycle of wind turbines,from production to recycling.As wind power rapidly deve...Compared with traditional energy sources,wind power has a lower environmental impact.However,emissions are still generated across the life cycle of wind turbines,from production to recycling.As wind power rapidly develops and deployment increases,these impacts are becoming increasingly evident.A comprehensive understanding of these impacts is crucial for sustainable development.Based on the harmonization of previous detailed life cycle assessment(LCA)studies,this study develops a simplified LCA model that estimates the life cycle environmental impacts of wind turbines based on their nominal power.Using this simplified LCA model,we assess the global warming potential(GWP),acidification potential(AP),and cumulative energy demand(CED)of wind power at the regional scale for 2022 and under three future scenarios(high-power wind turbine promotion,reduced wind curtailment,and a comprehensive development scenario).The results indicate that in 2022,the life cycle GWP,AP,and CED of wind power in western China were 10.76 g CO_(2) eq/kWh,0.177 g SO_(2) eq/kWh,and 17.6 kJ/kWh,respectively.Scenario simulations suggest that reducing wind curtailment is the most effective approach for reducing emissions in Inner Mongolia,Gansu,Qinghai,Ningxia,and Xinjiang,producing average decreases of 8.64%in GWP,8.39%in AP,and 9.26%in CED.In contrast,for Guangxi,Chongqing,Sichuan,Guizhou,Yunnan,Xizang,and Shaanxi,the promotion of high-power wind turbines provides greater environmental benefits than reducing curtailment,producing average decreases of 3.45%,3.09%,and 4.29%in GWP,AP,and CED,respectively.These findings help clarify the environmental impact of wind power across its life cycle at the regional scale and provide theoretical references for the direction of future wind power development and the formulation of related policies.展开更多
The dust cycle is a crucial component of the present-day Martian climate system.This study examines its multitimescale variability using an optimized 50-year simulation with the fully interactive scheme from the Globa...The dust cycle is a crucial component of the present-day Martian climate system.This study examines its multitimescale variability using an optimized 50-year simulation with the fully interactive scheme from the Global Open Planetary Atmospheric Model for Mars(GoMars),a newly developed Mars General Circulation Model(MGCM).GoMars is able to reproduce the diurnal,seasonal,and interannual characteristics of the dust cycle in several key aspects,with high repeatability in diurnal and seasonal variations during non-global dust storm(non-GDS)years.The model’s“climatology”(non-GDS years ensemble mean)captures the seasonal pattern and magnitude of the vertical–meridional dust distribution,validated against Mars Climate Database and Mars Climate Sounder observations.In the absence of direct observations,the GoMars-simulated near-surface wind stress lifting flux is evaluated through comparisons with other MGCMs(e.g.,MarsWRF),revealing consistent seasonal and spatial patterns.As for the diurnal cycle,the peak dust devil lifting flux occurs at 1200–1300 local time,matching the Mars Pathfinder measurements.The model also successfully captures the intense dust devil activity in Amazonis,a region identified as a major dust devil hotspot based on observational data.In GDS years,GoMars effectively reproduces spontaneous GDSs,capturing their observed onset times,locations,and dust transport patterns as exhibited in specific Martian years.The model also simulates significant interannual variability,with irregular GDS intervals along with reasonable dust–atmosphere interactions.展开更多
The airflow mechanics in adult nasal airways,whether healthy or abnormal,are extensively studied and investigated,but the flow mechanics in child nasal airways remain underexplored.This study investigates the airflow ...The airflow mechanics in adult nasal airways,whether healthy or abnormal,are extensively studied and investigated,but the flow mechanics in child nasal airways remain underexplored.This study investigates the airflow mechanics in the child’s nasal upper airway with adenoid hypertrophy,with an adenoid nasopharyngeal ratio(AN of 0.9),under cyclic inhalation and exhalation.An inlet respiratory cycle with three different flow rates(3.2 L/min calm breathing,8.6 L/min normal breathing,and 19.3 L/min intensive breathing)was simulated by using the computational fluid dynamics approach.To better capture the interaction between airflow and the flexible airway tissue,fluid-structure interaction analysis was performed at the normal breathing rate.Comparing the airflow dynamics during inhalation and exhalation,the pressure drops,nasal resistance,and wall shear stress show significant differences in the nasopharyngeal region for all different flow rates.This observation suggests that the inertial effect associated with the transient flow is important during exhalation and inhalation.Furthermore,the considerable temporal variation in flow rate distribution across a specific cross-section of the nasal airway highlights the critical role of transient data in virtual surgery planning and data for clinical decisions.展开更多
Hair loss,a multifactorial disorder characterized by follicular miniaturization and excessive shedding,significantly impairs psychological well-being and quality of life.Cyperus rotundus rhizome(CR),a traditional Chin...Hair loss,a multifactorial disorder characterized by follicular miniaturization and excessive shedding,significantly impairs psychological well-being and quality of life.Cyperus rotundus rhizome(CR),a traditional Chinese medicine used for various ailments,has not been evaluated for efficacy in treating hair loss.This study presents the first comprehensive assessment of the hair growth-promoting effects of ethanol extract from CR on mouse primary dermal papilla cells(MDPCs)and human immortalized hair DPCs(IHHDPCs),employing cell counting kit-8(CCK-8),scratch assay,reverse transcription-quantitative polymerase chain reaction(RT-q PCR),and Western blot(WB).CR treatment activated the Wnt/β-Catenin signaling pathway by upregulating Wnt10b,increasingβ-Catenin protein levels and promoting its nuclear translocation,while simultaneously downregulating transforming growth factor-beta 1(TGF-β1),BMP4,and dickkopf-related protein 1(DKK1)in MDPCs.These molecular changes enhanced cell proliferation and increased secretion of key growth factors—insulin-like growth factor 1(IGF1),keratinocyte growth factor(KGF),and vascular endothelial growth factor(VEGF)—thereby stimulating hair growth and prolonging the anagen phase,which was confirmed in an ex vivo hair follicle(HF)organ culture model.Chromatographic analysis identified the petroleum ether fraction(CRP),enriched in sesquiterpenes,as the primary bioactive component.Both CR and CRP promoted IHHDPC proliferation,migration,and growth factor expression through activation of the Wnt/β-Catenin pathway,with CRP exhibiting superior bioactivity.Furthermore,both treatments stimulated HF cycling,increased follicular density,and upregulated Ki67 andβ-Catenin expression in the dorsal skin of C57BL/6 mice.Collectively,these findings demonstrate that CR and CRP promote hair growth and modulate the hair cycle via enhancement of Wnt/β-Catenin signaling,providing a scientific basis for the potential clinical application of C.rotundus rhizomes in hair loss therapy and the development of related pharmaceuticals or cosmetics.展开更多
To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,...To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,Scanning Electron Microscopy(SEM),and Nuclear Magnetic Resonance(NMR)experiments were conducted.The mechanical property degradation laws and evolution characteristics of the microscopic pore structure of moraine soil under Freeze-Thaw(F-T)conditions were revealed.After F-T cycles,the stress-strain curves of moraine soil showed a strain-softening trend.In the early stage of F-T cycles(0–5 cycles),the shear strength and elastic modulus exhibited damage rate of approximately 10.33%±0.8%and 16.60%±1.2%,respectively.In the later stage(10–20 cycles),the strength parameters fluctuated slightly and tended to stabilize.The number of F-T cycles was negatively exponentially correlated with cohesion,while showing only slight fluctuation in the internal friction angle,thereby extending the Mohr-Coulomb strength criterion for moraine soil under F-T cycles.The NMR experiments quantitatively characterized the evolution of the internal pore structure of moraine soil under F-T cycles.As the number of F-T cycles increased,fine and micro pores gradually expanded and merged due to the frost-heaving effect during the water-ice phase transition,forming larger pores.The proportion of large and medium pores increased to 59.55%±2.1%(N=20),while that of fine and micro pores decreased to 40.45%±2.1%(N=20).The evolution of pore structure characteristics was essentially completed in the later stage of F-T cycles(10–20 cycles).This study provides a theoretical foundation and technical support for major engineering construction and disaster prevention in the Qinghai-Xizang Plateau.展开更多
The conversion of CO_(2) into high value added chemicals via the Fischer-Tropsch synthesis(FTS)reaction has attracted significant attention.The surface oxygenation environment is a significant factor influencing the p...The conversion of CO_(2) into high value added chemicals via the Fischer-Tropsch synthesis(FTS)reaction has attracted significant attention.The surface oxygenation environment is a significant factor influencing the performance of the catalyst.In this work,spin-polarized density-functional theory calculations have been used to investigate the adsorption and reactions of CO_(2) and H to generate CH4 and CH3OH on Fe_(5)C_(2)(100)surfaces with varying OH∗coverage.On the pure Fe_(5)C_(2)(100)surface,surface C^(∗) preferentially reacts with hydrogen to form CH4,exposing C^(∗) vacancy.CO_(2) favors adsorbing on the C^(∗) vacancy to further dissociating and activating.The co-adsorption of OH∗promotes the C^(∗) cycle process by facilitating the hydrogenation of C^(∗).The Fe_(5)C_(2) surface with an oxide interface is favorable for reducing FexOy,thereby maintaining the dynamic stability of the surface.Therefore,surface oxidation is inevitably involved in the entire C^(∗) cycle of the FTS reaction and regulates the relative content of iron oxides and iron carbides.Our work can contribute to the rational modulation of the surface C^(∗) cycle,thereby enhancing catalyst performance.展开更多
Lithium-oxygen(Li-O_(2))battery is favored among“beyond lithiumion”technologies for sustainability because of its exceptional energy density.Major impediments are the poor cycle stability and grievous capacity degra...Lithium-oxygen(Li-O_(2))battery is favored among“beyond lithiumion”technologies for sustainability because of its exceptional energy density.Major impediments are the poor cycle stability and grievous capacity degradation at high current densities.We address these issues by a“killing two birds with one stone”O_(2)-pressure protocol.It first resolves efficient O_(2) mass transport at high rates..The accelerated reaction kinetics optimizes the composition and growth pathway of discharge products.This protocol secondly achieves protection of Li anodes via densifying corrosion layers on them.Consequently,the battery delivers both ultrahigh discharge capacity(>9,000 mAh g^(-1))at 3,000 mA g^(-1) and excellent cycling stability.Under a dual-strategy effect of high-pressure O_(2) and artificial protection layers,the battery actualizes over 11-fold increase in cycle life of 5,170 h(2,585 cycles).The strategy opens avenues for advancing Li-O_(2) batteries towards practical application and confers the extension to other gas-based batteries.展开更多
Loess landslides are major hazards in the Chinese Loess Plateau(CLP).The loess in this region is frequently subjected to repeated wetting–drying(W-D)cycles due to climatic factors,which significantly increases the li...Loess landslides are major hazards in the Chinese Loess Plateau(CLP).The loess in this region is frequently subjected to repeated wetting–drying(W-D)cycles due to climatic factors,which significantly increases the likelihood of landslides.Therefore,investigating the shear behavior and microstructural evolution of loess under climate-induced W-D cycles is crucial to understanding the mechanisms of loess landslides.In this study,Malan loess is analyzed using unsaturated triaxial tests,resistivity tests,scanning electron microscopy,and mercury intrusion porosimetry.The test results show that shear strength decreases with increased W-D cycles,and the degradation effect is more pronounced under lower confining pressure.The variations in conductive pathways indicate that electrical resistivity can effectively reflect the structural damage of loess during W-D cycles,which is associated with increased direct point contacts and spaced pores.Aggregation of clay particles and growth of cracks during the W-D cycles can further destabilize the loess microstructure.As the confining pressure increases,crushed particles rearrange and convert spaced pores into intergranular pores.The number and peak intensity of dominant spaced pores decrease,resulting in a more stable structure.This study clarifies the mechanisms of loess landslides under W-D cycles and provides theoretical support for landslide prevention and control in the CLP.展开更多
Investigating the damage evolution of surrounding rock under thermal shock cycles is crucial for ensuring the stability of engineering rock masses.This study performed Brazilian splitting tests on granite specimens un...Investigating the damage evolution of surrounding rock under thermal shock cycles is crucial for ensuring the stability of engineering rock masses.This study performed Brazilian splitting tests on granite specimens under varying temperature and cycle conditions,employing acoustic emission monitoring,digital image correlation,and three-dimensional scanning technology.A systematic analysis was conducted on the patterns of damage evolution,failure precursor,and response mechanisms under combined thermal and cyclic loading.Experimental results show that both P-wave velocity and tensile strength degrade significantly with increasing temperature and cycle count,with temperature having a more pronounced effect than cycle count.Notably,damage evolution exhibits a dual-threshold behavior in which degradation accelerates markedly above 400℃ and stabilizes after 5 thermal cycles.Fracture surfaces evolve from initially planar to rugged morphologies,with peak-valley height differences at 600℃ being approximately three times greater than those at 200℃.Furthermore,based on acoustic emission energy entropy analysis,we introduce a novel failure precursor indicator where the sustained increase and critical surge in average entropy serve as reliable early-warning signals for impending rock failure.These findings establish a solid theoretical basis and practical methodology for damage assessment and instability early-warning systems in high-temperature rock engineering.展开更多
Bio-carbonation of reactive MgO has been regarded as a promising and eco-friendly method for construction and demolition waste(CDW)cementation in various geotechnical engineering applications.However,the beneficial ef...Bio-carbonation of reactive MgO has been regarded as a promising and eco-friendly method for construction and demolition waste(CDW)cementation in various geotechnical engineering applications.However,the beneficial effect of bio-carbonation of reactive MgO cemented CDW(BCM-samples)can be altered when exposed to wetting-drying cycles induced by extreme climate changes or groundwater fluctuations.To better understand the durability of BCM-samples and their underlying deterioration mechanisms,a series of BCM-samples was prepared to investigate their physical-mechanical performance and microstructure evolution subjected to the wetting-drying cycles.The results indicated that the wetting-drying cycles can deteriorate the BCM-samples,and their physical-mechanical behaviors change quickly at the cycle beginning and then smoothly after 2 cycles.With the increase in cycling,the apparent deterioration with efflorescence and microcrack development can be observed.The mass loss and water absorption rates increased while the dry density,compressional wave velocity,and unconfined compression strength decreased.Urea pre-hydrolysis treatment can significantly improve the durability of BCM-samples,as the more hydrated magnesia carbonates(HMCs)enhance the cementing effects.After 10 cycles,the UCS of pre-hydrolyzed samples decreased 25.4%to 4.45 MPa,while that of ordinary samples decreased 50.7%to 1.20 MPa.The deterioration of BCM-samples caused by wetting-drying cycles can be attributed to two factors.One of the main factors is the structural integrity changes caused by the rapid loss of soluble material at the initial cycling stages.Another factor is the decrease in cementation induced by the loss of brucite and HMCs at the following cycle stages.展开更多
Freeze-thaw cycles(FTCs)have an important effect on soil aggregate stability by altering soil structures,thereby influencing soil wind and water erosion on the eastern Qinghai-Tibet Plateau.However,the effects of FTCs...Freeze-thaw cycles(FTCs)have an important effect on soil aggregate stability by altering soil structures,thereby influencing soil wind and water erosion on the eastern Qinghai-Tibet Plateau.However,the effects of FTCs on the stability of these soils remain unclear.Here,we conducted freeze-thaw simulations in laboratory to investigate the effects of FTCs(0 to 15 cycles)on the wet-and dry-sieving aggregate stability of undisturbed sandy loam from Maqu county,which was treated with different initial soil moisture contents(1%to 25%in increments of 4%)and initial aggregate diameters(<2,2-5,5-10,and 10-15 mm).Results show that soil aggregates with initial diameters larger than 2 mm exhibit higher soil organic carbon contents(1.45%-1.57%)and silt contents(34.63%-35.52%)than those smaller than 2 mm(0.93%and 31.38%,respectively).The stability of both wet-and dry-sieving aggregates increases with larger initial diameters.Increasing initial soil moisture content from 1%to 25%reduces aggregate stability,with reductions of 2.4%-88.0%for wet-sieving aggregates and 2.1%-25.5%for dry-sieving aggregates(>2 mm).With increasing FTCs,wet-sieving aggregate(>2 mm)stability exhibits a fluctuating upward trend,with increases of 79.2%-87.4%after 15 FTCs,while dry-sieving aggregate(>2 mm)stability decreases significantly(5.7%-21.7%)upon the first FTC and remains unchanged thereafter.The stability of both the wet-and dry-sieving aggregates smaller than 2 mm remains unchanged with increasing FTCs(p>0.05).SOC content decreases by 22.3%on average with increasing FTCs from 1 to 15 and shows no significant correlations with wet-and dry-sieving aggregate stability.Higher silt content(r=0.39,p<0.05)and lower sand content(r=-0.38,p<0.05)enhances the wet-sieving aggregate stability of sandy loam.Frequent FTCs tend to improve wet-sieving aggregate stability but reduce dry-sieving aggregate stability in the sandy loam.The findings provide certain guidance for preventing freeze-thaw-induced wind erosion.展开更多
The rapid cycling synchrotron(RCS)at the China spallation neutron source operates as a high-intensity proton accelerator.The coupled bunch instability was observed during RCS beam commissioning,which significantly lim...The rapid cycling synchrotron(RCS)at the China spallation neutron source operates as a high-intensity proton accelerator.The coupled bunch instability was observed during RCS beam commissioning,which significantly limited the beam power.To investigate the dynamics of instability under an increased beam power,a pulsed octupole magnet with a gradient of 900 T/m^(3) was developed.The magnet system integrated an octupole magnet with a pulsed power supply.The field was carefully measured to examine the performance before its installation into the tunnel.After the installation of the magnets,beam measurements were performed to confirm the effectiveness of the instability mitigation on an actual proton beam.The measurement results show that the instability can be suppressed using the pulsed octupole magnet,particularly at the highenergy stage in an acceleration cycle,meeting the requirements for stable operation of the accelerator.Additionally,when the instability is completely suppressed through chromaticity optimization,octupole magnets can significantly enhance the RCS transmission efficiency,which is crucial for controlling beam loss.The pulsed octupole magnet offers significant progress in beam stability in the RCS,providing valuable experience for further beam power enhancement.展开更多
Objective:MicroRNAs(miRNAs)are small,non-coding RNAs that play a key role in the development of chemoresistance in various cancer types,including colorectal cancer(CRC).In this study,we aimed to study the underlying m...Objective:MicroRNAs(miRNAs)are small,non-coding RNAs that play a key role in the development of chemoresistance in various cancer types,including colorectal cancer(CRC).In this study,we aimed to study the underlying mechanisms of miRNA in chemotherapy-resistant CRC.Methods:LoVo CRC cell line was exposed to oxaliplatin at an increased dose,and cells were cultured in the presence of oxaliplatin to develop LoVo^(OXR) cells.Microarray and Quantitative Reverse Transcription Polymerase Chain Reaction(qRT-PCR),western blot,and transwell assay were used to evaluate the chemoresistance in LoVo^(OXR) CRC cells.Results:Microarray and qRT-PCR analysis showed an increased expression of miR-100-5p in LoVo^(OXR) cells.MTT assay and flow cytometry analysis revealed less apoptosis and higher cell viability in LoVo^(OXR) cells.mRNA prediction target gene analysis showed C-terminal domain small phosphatase-like(CTDSPL),a phosphatase-like tumor suppressor,as a key target of miR-100-5p.CTDSPL expression was low in LoVo^(OXR) cells compared to LoVoWT cells.miR-100-5p regulates G1/S and S-phase transitions and inhibits differentiation by targeting the CTDSPL/pRB/E2F1 signaling pathway,which involves the modulation of cell cycle effectors in LoVo^(OXR) cells.Further,we found that forkhead box P3(FOXP3),as the upstream target of miR-100-5p,is highly expressed in LoVo^(OXR) cells.Inhibiting miR-100-5p and FOXP3 down-regulates miR-100-5p expression,while increased CTDSPL expression contributed to reduced cell proliferation and promoted cell apoptosis in LoVo^(OXR) CRC cells.Conclusions:miR-100-5p plays an oncogenic role in inducing chemoresistance through modulation of the CTDSPL/retinoblastoma protein(pRB)/E2F transcription factor 1(E2F1)axis in CRC cells.展开更多
Cell cycle kinetic activity in the cortical cells of the lentil (Lens culinaris Me-die. cv. Verte du Puy) primary root during germination was examined both temporally and spatially. Immunohistochemical and cytological...Cell cycle kinetic activity in the cortical cells of the lentil (Lens culinaris Me-die. cv. Verte du Puy) primary root during germination was examined both temporally and spatially. Immunohistochemical and cytological evidence indicated that DNA replication and cell division started in the cortical cells of tire lentil primary root after around 13 and 17 h of imbibition, respectively. The first cells in DNA synthesis and the First mitotic figures all appeared in the cortical cells about I mm front the root-cap junction, but these divided cells had synthesized their DNA during the maturity of seed instead of during germination. The kinetic pattern of activity of the first cell cycle showed that these cells were not activated synchronously, but re-entered the cell cycle in turn depending on their places in the root tip, However, the adjacent cells partially synchronously proceeded their cell cycle.展开更多
基金funded by the Technology Funding Scheme of China Construction Second Engineering Bureau LTD(2020ZX150002)the National Natural Science Foundation Project of China(12262018).
文摘To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requires immediate investigation.In view of this phenomenon,the durability of unit lining concrete is predicted by analyzing three key indicators:carbonation depth,relative dynamic elastic modulus,and residual quality.This prediction is achieved by integrating the Entropy Weight Method,Grey theory life prediction model and BP artificial neural networks using data from tests and predictions of these indicators.Then,the Entropy Weight-Grey theory-BP Network Model is compared with other methods to analyze the predicted life.Finally,verify the sci-entificity of this model,and the optimum silica fume content of unit concrete lining is verified.The results showed,1)The addition of silica fume will accelerate the carbonization of unit concrete lining,and slow down the freeze-thaw cycle and sulfate erosion.2)The utilization of artificial neural networks is essential for enhancing the realism of the data,as it emphasizes the significance of silica fume content.3)Silica fume content of 10%results in the longest life and is the most suitable for lining construction.4)A comparison between single-factor and multi-factor predictions indicates that the multi-factor approach yields a longer maximum life.This improvement can be attributed to the inclusion of additional factors,such as freeze-thaw cycles and carbonation,which enhance the predicted life when employing these methods.In conclusion,the Entropy Weight-Grey Theory-BP Network life prediction Model is well-suited for tunnel lining in the alpine sulfate area of northwest China.
基金Supported by National Natural Science Foundation of China(Grant Nos.52192634,52305015,52335003)Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515011268)Science and Technology Innovation Committee of Shenzhen(Grant Nos.GXWD20231129102029003,KQTD20210811090146075).
文摘The intricate relationship between origami and mechanism underscores the fertile ground for innovation,which is particularly evident in the construction theory of thick-panel origami.Despite its potential,thick panel origami remains relatively unexplored in the context of single-loop metamorphic mechanisms.Drawing inspiration from thickpanel origami,particularly Miura origami,this study proposes a pioneering single-loop 6R multiple metamorphic mechanism.Through rigorous mathematical modeling(including the construction and resolution of the D-H closed-loop equation)and leveraging advanced analytical tools such as the screw theory and Lie theory,this study meticulously elucidates the planar,spherical,and Bennett motion branches of the mechanism.Furthermore,it delineates all the three bifurcation points between the motion branches,thereby providing a comprehensive understanding of the kinematic behavior of the mechanism.A metamorphic network can be constructed by applying several single-loop mechanisms to a symmetrical layout.Owing to its metamorphic properties,this network can act as a structural backbone for deployable antennas,aerospace shelters,and morphing wing units,thereby enabling a single mechanism to achieve multiple folding configurations.This paper not only introduces innovative metamorphic mechanisms but also suggests a promising method for uncovering and designing metamorphic mechanisms by developing new mechanisms from thick-panel origami.
基金supported by the National Science and Tech-nology Major Project,China(No.J2019-II-0012-0032)。
文摘The coupling effects among the flow field,temperature distribution and structural deformation in a turbine cannot be ignored,particularly during flight cycles when the turbine experiences varied operational states.Relying solely on steady-state solutions cannot predict the detrimental effects caused by hysteresis.Consequently,this paper employs a quasi-steady-state fluid-thermalstructure multidisciplinary coupling solution method,integrating transient solid heat conduction with steady-state flow field and static structural deformation solutions.After conducting a numerical simulation of a three-dimensional,five-stage,low-pressure turbine air system,the following conclusions are drawn:when boundary conditions attain high-power states through processes that are numerically identical but in opposite directions,slight variations in solid deformation significantly impact the flow field;when boundary conditions attain high-power states through processes that are directionally consistent but have different numerical values,the influence of the boundary condition change rate on the flow field surpasses that of solid deformation.In terms of turbine design parameters,a large difference in stage-reaction between adjacent stages at the lower radius of the turbine can lead to significant changes in the disc cavity flow field during flight cycles.The difference in the stage-reaction of 0.23 at 10%blade height in adjacent stages may induce severe gas ingress in the stator disc cavity.Thus,it is crucial to minimize this difference and to appropriately extend the duration of the deceleration phase to ensure the turbine's safe operation.
基金Funded by the Science and Technology Program of Gansu Province(Nos.25JRRA497,23ZDFA017)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0950000)High-level Talent Funding of Kashi。
文摘This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw resistance and durability of recycled concrete samples under varying freeze-thaw cycles.The results indicate that an appropriate addition of SAP significantly enhances the freeze-thaw resistance of recycled concrete.After 200 freeze-thaw cycles,the RS0.6 sample retained good surface integrity,demonstrating the best performance.Compared to NAC,its mass loss decreased by 1.16%,the relative dynamic modulus improved by 7.01%,and the compressive strength loss rate decreased by 5.41%.Additionally,T2 spectrum analysis revealed that adding SAP optimized the pore structure of recycled concrete and mitigated pore development during freeze-thaw cycles.As the number of freeze-thaw cycles increased,the RS0.3 and RS0.6 samples demonstrated superior frost resistance compared to NAC.However,an excessive amount of SAP increased pore expansion during subsequent freeze-thaw cycles,ultimately weakening frost resistance.
基金supported by the Jilin Science and Technology Program(20230203130SF)。
文摘Freeze–thaw(F–T)cycle-induced cracking in silty clays poses a significant risk to engineering stability.Although the individual addition of fly ash(FA)or sisal fiber(SF)provides partial solutions,their simultaneous application may result in a synergistic effect to compensate for their respective shortcomings.In this study,the effects of SF and FA on the mechanical properties,crack resistance,water retention,and erosion resistance of improved soil were systematically investigated through unconfined compressive strength(UCS)tests,crack evolution analysis,simulated rainfall erosion tests,and microscopic characterization(laser particle size analysis and nitrogen adsorption).The results reveal that the volumetric stability of FA particles significantly inhibits cracking in soil after F–T cycles.However,FA contributes only slightly to soil strength and erosion resistance.SF,on the other hand,plays a substantial role in increasing both soil strength and erosion resistance.The synergy between FA and SF results in the simultaneous increase in crack resistance,erosion resistance,and strength.FA improves the aggregate stability during F–T cycles,whereas SF reinforces the bonds between these aggregates.A comprehensive evaluation of the improved soil during F–T cycles using the entropy weight-TOPSIS method reveal that the combination of 10%FA+18 mm SF performed the best,achieving a 246%higher composite score than the unmodified soil did.With respect to this optimal combination,compared with the unmodified soil,the SF–FA-improved soil exhibits a 30%reduction in the average crack width,a 30%reduction in the erosion rate,and a 46%increase in strength.The findings of this study provide a scientific basis for the design of soil improvement in disaster mitigation engineering in seasonally frozen soil regions.
基金supported by the Academic Research Projects of Beijing Union University(ZK20202204)the National Natural Science Foundation of China(12250005,12073040,12273059,11973056,12003051,11573037,12073041,11427901,11572005,11611530679 and 12473052)+1 种基金the Strategic Priority Research Program of the China Academy of Sciences(XDB0560000,XDA15052200,XDB09040200,XDA15010700,XDB0560301,and XDA15320102)the Chinese Meridian Project(CMP).
文摘The solar cycle(SC),a phenomenon caused by the quasi-periodic regular activities in the Sun,occurs approximately every 11 years.Intense solar activity can disrupt the Earth’s ionosphere,affecting communication and navigation systems.Consequently,accurately predicting the intensity of the SC holds great significance,but predicting the SC involves a long-term time series,and many existing time series forecasting methods have fallen short in terms of accuracy and efficiency.The Time-series Dense Encoder model is a deep learning solution tailored for long time series prediction.Based on a multi-layer perceptron structure,it outperforms the best previously existing models in accuracy,while being efficiently trainable on general datasets.We propose a method based on this model for SC forecasting.Using a trained model,we predict the test set from SC 19 to SC 25 with an average mean absolute percentage error of 32.02,root mean square error of 30.3,mean absolute error of 23.32,and R^(2)(coefficient of determination)of 0.76,outperforming other deep learning models in terms of accuracy and training efficiency on sunspot number datasets.Subsequently,we use it to predict the peaks of SC 25 and SC 26.For SC 25,the peak time has ended,but a stronger peak is predicted for SC 26,of 199.3,within a range of 170.8-221.9,projected to occur during April 2034.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF1303405).
文摘Compared with traditional energy sources,wind power has a lower environmental impact.However,emissions are still generated across the life cycle of wind turbines,from production to recycling.As wind power rapidly develops and deployment increases,these impacts are becoming increasingly evident.A comprehensive understanding of these impacts is crucial for sustainable development.Based on the harmonization of previous detailed life cycle assessment(LCA)studies,this study develops a simplified LCA model that estimates the life cycle environmental impacts of wind turbines based on their nominal power.Using this simplified LCA model,we assess the global warming potential(GWP),acidification potential(AP),and cumulative energy demand(CED)of wind power at the regional scale for 2022 and under three future scenarios(high-power wind turbine promotion,reduced wind curtailment,and a comprehensive development scenario).The results indicate that in 2022,the life cycle GWP,AP,and CED of wind power in western China were 10.76 g CO_(2) eq/kWh,0.177 g SO_(2) eq/kWh,and 17.6 kJ/kWh,respectively.Scenario simulations suggest that reducing wind curtailment is the most effective approach for reducing emissions in Inner Mongolia,Gansu,Qinghai,Ningxia,and Xinjiang,producing average decreases of 8.64%in GWP,8.39%in AP,and 9.26%in CED.In contrast,for Guangxi,Chongqing,Sichuan,Guizhou,Yunnan,Xizang,and Shaanxi,the promotion of high-power wind turbines provides greater environmental benefits than reducing curtailment,producing average decreases of 3.45%,3.09%,and 4.29%in GWP,AP,and CED,respectively.These findings help clarify the environmental impact of wind power across its life cycle at the regional scale and provide theoretical references for the direction of future wind power development and the formulation of related policies.
基金jointly supported by the National Natural Science Foundation of China(Grant No.42475135)the Key Technology Research Project of TW-3(TW3006)the IAP’s basic scientific research project during the 14th Five-Year Plan Period.
文摘The dust cycle is a crucial component of the present-day Martian climate system.This study examines its multitimescale variability using an optimized 50-year simulation with the fully interactive scheme from the Global Open Planetary Atmospheric Model for Mars(GoMars),a newly developed Mars General Circulation Model(MGCM).GoMars is able to reproduce the diurnal,seasonal,and interannual characteristics of the dust cycle in several key aspects,with high repeatability in diurnal and seasonal variations during non-global dust storm(non-GDS)years.The model’s“climatology”(non-GDS years ensemble mean)captures the seasonal pattern and magnitude of the vertical–meridional dust distribution,validated against Mars Climate Database and Mars Climate Sounder observations.In the absence of direct observations,the GoMars-simulated near-surface wind stress lifting flux is evaluated through comparisons with other MGCMs(e.g.,MarsWRF),revealing consistent seasonal and spatial patterns.As for the diurnal cycle,the peak dust devil lifting flux occurs at 1200–1300 local time,matching the Mars Pathfinder measurements.The model also successfully captures the intense dust devil activity in Amazonis,a region identified as a major dust devil hotspot based on observational data.In GDS years,GoMars effectively reproduces spontaneous GDSs,capturing their observed onset times,locations,and dust transport patterns as exhibited in specific Martian years.The model also simulates significant interannual variability,with irregular GDS intervals along with reasonable dust–atmosphere interactions.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0707601).
文摘The airflow mechanics in adult nasal airways,whether healthy or abnormal,are extensively studied and investigated,but the flow mechanics in child nasal airways remain underexplored.This study investigates the airflow mechanics in the child’s nasal upper airway with adenoid hypertrophy,with an adenoid nasopharyngeal ratio(AN of 0.9),under cyclic inhalation and exhalation.An inlet respiratory cycle with three different flow rates(3.2 L/min calm breathing,8.6 L/min normal breathing,and 19.3 L/min intensive breathing)was simulated by using the computational fluid dynamics approach.To better capture the interaction between airflow and the flexible airway tissue,fluid-structure interaction analysis was performed at the normal breathing rate.Comparing the airflow dynamics during inhalation and exhalation,the pressure drops,nasal resistance,and wall shear stress show significant differences in the nasopharyngeal region for all different flow rates.This observation suggests that the inertial effect associated with the transient flow is important during exhalation and inhalation.Furthermore,the considerable temporal variation in flow rate distribution across a specific cross-section of the nasal airway highlights the critical role of transient data in virtual surgery planning and data for clinical decisions.
基金supported by the Start-up Fund of China Pharmaceutical University(No.3150020057)。
文摘Hair loss,a multifactorial disorder characterized by follicular miniaturization and excessive shedding,significantly impairs psychological well-being and quality of life.Cyperus rotundus rhizome(CR),a traditional Chinese medicine used for various ailments,has not been evaluated for efficacy in treating hair loss.This study presents the first comprehensive assessment of the hair growth-promoting effects of ethanol extract from CR on mouse primary dermal papilla cells(MDPCs)and human immortalized hair DPCs(IHHDPCs),employing cell counting kit-8(CCK-8),scratch assay,reverse transcription-quantitative polymerase chain reaction(RT-q PCR),and Western blot(WB).CR treatment activated the Wnt/β-Catenin signaling pathway by upregulating Wnt10b,increasingβ-Catenin protein levels and promoting its nuclear translocation,while simultaneously downregulating transforming growth factor-beta 1(TGF-β1),BMP4,and dickkopf-related protein 1(DKK1)in MDPCs.These molecular changes enhanced cell proliferation and increased secretion of key growth factors—insulin-like growth factor 1(IGF1),keratinocyte growth factor(KGF),and vascular endothelial growth factor(VEGF)—thereby stimulating hair growth and prolonging the anagen phase,which was confirmed in an ex vivo hair follicle(HF)organ culture model.Chromatographic analysis identified the petroleum ether fraction(CRP),enriched in sesquiterpenes,as the primary bioactive component.Both CR and CRP promoted IHHDPC proliferation,migration,and growth factor expression through activation of the Wnt/β-Catenin pathway,with CRP exhibiting superior bioactivity.Furthermore,both treatments stimulated HF cycling,increased follicular density,and upregulated Ki67 andβ-Catenin expression in the dorsal skin of C57BL/6 mice.Collectively,these findings demonstrate that CR and CRP promote hair growth and modulate the hair cycle via enhancement of Wnt/β-Catenin signaling,providing a scientific basis for the potential clinical application of C.rotundus rhizomes in hair loss therapy and the development of related pharmaceuticals or cosmetics.
基金support from the National Natural Science Foundation of China(Grant Nos.42107193,42077245)supported by the Sichuan Science and Technology Program(2025YFNH0008,2025YFNH0004)+1 种基金the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(SKLGP2023Z006)the Everest Scientific Research Program 2.0:Research on mechanism and control of glacial lake outburst chain catastrophe in Qinghai-Xizang Plateau based on man-earth coordination perspective.
文摘To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,Scanning Electron Microscopy(SEM),and Nuclear Magnetic Resonance(NMR)experiments were conducted.The mechanical property degradation laws and evolution characteristics of the microscopic pore structure of moraine soil under Freeze-Thaw(F-T)conditions were revealed.After F-T cycles,the stress-strain curves of moraine soil showed a strain-softening trend.In the early stage of F-T cycles(0–5 cycles),the shear strength and elastic modulus exhibited damage rate of approximately 10.33%±0.8%and 16.60%±1.2%,respectively.In the later stage(10–20 cycles),the strength parameters fluctuated slightly and tended to stabilize.The number of F-T cycles was negatively exponentially correlated with cohesion,while showing only slight fluctuation in the internal friction angle,thereby extending the Mohr-Coulomb strength criterion for moraine soil under F-T cycles.The NMR experiments quantitatively characterized the evolution of the internal pore structure of moraine soil under F-T cycles.As the number of F-T cycles increased,fine and micro pores gradually expanded and merged due to the frost-heaving effect during the water-ice phase transition,forming larger pores.The proportion of large and medium pores increased to 59.55%±2.1%(N=20),while that of fine and micro pores decreased to 40.45%±2.1%(N=20).The evolution of pore structure characteristics was essentially completed in the later stage of F-T cycles(10–20 cycles).This study provides a theoretical foundation and technical support for major engineering construction and disaster prevention in the Qinghai-Xizang Plateau.
基金the National Natural Science Foundation of China(22002008,22202226,22468042)Ningxia Key Research and Development Project(2022BEE03002,2022 BSB03056)+1 种基金the Fourth Batch of Ningxia Youth Talents Supporting Program(TJGC2019022)West Light Foundation of the Chinese Academy of Sciences(XAB2019AW02).
文摘The conversion of CO_(2) into high value added chemicals via the Fischer-Tropsch synthesis(FTS)reaction has attracted significant attention.The surface oxygenation environment is a significant factor influencing the performance of the catalyst.In this work,spin-polarized density-functional theory calculations have been used to investigate the adsorption and reactions of CO_(2) and H to generate CH4 and CH3OH on Fe_(5)C_(2)(100)surfaces with varying OH∗coverage.On the pure Fe_(5)C_(2)(100)surface,surface C^(∗) preferentially reacts with hydrogen to form CH4,exposing C^(∗) vacancy.CO_(2) favors adsorbing on the C^(∗) vacancy to further dissociating and activating.The co-adsorption of OH∗promotes the C^(∗) cycle process by facilitating the hydrogenation of C^(∗).The Fe_(5)C_(2) surface with an oxide interface is favorable for reducing FexOy,thereby maintaining the dynamic stability of the surface.Therefore,surface oxidation is inevitably involved in the entire C^(∗) cycle of the FTS reaction and regulates the relative content of iron oxides and iron carbides.Our work can contribute to the rational modulation of the surface C^(∗) cycle,thereby enhancing catalyst performance.
基金support from the Major basic research project of Natural Science Foundation of Shandong Province(No.ZR2023ZD12)Singapore National Research Foundation Investigatorship(No.NRFNRFI08-2022-0009)NUS R&G Postdoc Fellowship Program.
文摘Lithium-oxygen(Li-O_(2))battery is favored among“beyond lithiumion”technologies for sustainability because of its exceptional energy density.Major impediments are the poor cycle stability and grievous capacity degradation at high current densities.We address these issues by a“killing two birds with one stone”O_(2)-pressure protocol.It first resolves efficient O_(2) mass transport at high rates..The accelerated reaction kinetics optimizes the composition and growth pathway of discharge products.This protocol secondly achieves protection of Li anodes via densifying corrosion layers on them.Consequently,the battery delivers both ultrahigh discharge capacity(>9,000 mAh g^(-1))at 3,000 mA g^(-1) and excellent cycling stability.Under a dual-strategy effect of high-pressure O_(2) and artificial protection layers,the battery actualizes over 11-fold increase in cycle life of 5,170 h(2,585 cycles).The strategy opens avenues for advancing Li-O_(2) batteries towards practical application and confers the extension to other gas-based batteries.
基金supported by the National Natural Science Foundation of China(Grant Nos.42177138 and 41907239)the Central Guidance Funds for Local Science and Technology Development of China(Grant No.YDZJSX2025D031).
文摘Loess landslides are major hazards in the Chinese Loess Plateau(CLP).The loess in this region is frequently subjected to repeated wetting–drying(W-D)cycles due to climatic factors,which significantly increases the likelihood of landslides.Therefore,investigating the shear behavior and microstructural evolution of loess under climate-induced W-D cycles is crucial to understanding the mechanisms of loess landslides.In this study,Malan loess is analyzed using unsaturated triaxial tests,resistivity tests,scanning electron microscopy,and mercury intrusion porosimetry.The test results show that shear strength decreases with increased W-D cycles,and the degradation effect is more pronounced under lower confining pressure.The variations in conductive pathways indicate that electrical resistivity can effectively reflect the structural damage of loess during W-D cycles,which is associated with increased direct point contacts and spaced pores.Aggregation of clay particles and growth of cracks during the W-D cycles can further destabilize the loess microstructure.As the confining pressure increases,crushed particles rearrange and convert spaced pores into intergranular pores.The number and peak intensity of dominant spaced pores decrease,resulting in a more stable structure.This study clarifies the mechanisms of loess landslides under W-D cycles and provides theoretical support for landslide prevention and control in the CLP.
基金supported by National Natural Science Foundation of China (Nos.52264006,52364004,and 52464005)the Guizhou Provincial Science and Technology Foundation (No.GCC[2022]005-1)。
文摘Investigating the damage evolution of surrounding rock under thermal shock cycles is crucial for ensuring the stability of engineering rock masses.This study performed Brazilian splitting tests on granite specimens under varying temperature and cycle conditions,employing acoustic emission monitoring,digital image correlation,and three-dimensional scanning technology.A systematic analysis was conducted on the patterns of damage evolution,failure precursor,and response mechanisms under combined thermal and cyclic loading.Experimental results show that both P-wave velocity and tensile strength degrade significantly with increasing temperature and cycle count,with temperature having a more pronounced effect than cycle count.Notably,damage evolution exhibits a dual-threshold behavior in which degradation accelerates markedly above 400℃ and stabilizes after 5 thermal cycles.Fracture surfaces evolve from initially planar to rugged morphologies,with peak-valley height differences at 600℃ being approximately three times greater than those at 200℃.Furthermore,based on acoustic emission energy entropy analysis,we introduce a novel failure precursor indicator where the sustained increase and critical surge in average entropy serve as reliable early-warning signals for impending rock failure.These findings establish a solid theoretical basis and practical methodology for damage assessment and instability early-warning systems in high-temperature rock engineering.
基金supported by the National Natural Science Foundation of China(Grant Nos.42525201 and 42230710).
文摘Bio-carbonation of reactive MgO has been regarded as a promising and eco-friendly method for construction and demolition waste(CDW)cementation in various geotechnical engineering applications.However,the beneficial effect of bio-carbonation of reactive MgO cemented CDW(BCM-samples)can be altered when exposed to wetting-drying cycles induced by extreme climate changes or groundwater fluctuations.To better understand the durability of BCM-samples and their underlying deterioration mechanisms,a series of BCM-samples was prepared to investigate their physical-mechanical performance and microstructure evolution subjected to the wetting-drying cycles.The results indicated that the wetting-drying cycles can deteriorate the BCM-samples,and their physical-mechanical behaviors change quickly at the cycle beginning and then smoothly after 2 cycles.With the increase in cycling,the apparent deterioration with efflorescence and microcrack development can be observed.The mass loss and water absorption rates increased while the dry density,compressional wave velocity,and unconfined compression strength decreased.Urea pre-hydrolysis treatment can significantly improve the durability of BCM-samples,as the more hydrated magnesia carbonates(HMCs)enhance the cementing effects.After 10 cycles,the UCS of pre-hydrolyzed samples decreased 25.4%to 4.45 MPa,while that of ordinary samples decreased 50.7%to 1.20 MPa.The deterioration of BCM-samples caused by wetting-drying cycles can be attributed to two factors.One of the main factors is the structural integrity changes caused by the rapid loss of soluble material at the initial cycling stages.Another factor is the decrease in cementation induced by the loss of brucite and HMCs at the following cycle stages.
基金supported by National Natural Science Foundation of China(Grant No.42201080)Young Scientific and Technological Talents Program of Shaanxi Province(Grant No.2025ZC-KJXX-57)Special Scientific Research Program of the Shaanxi Provincial Department of Education(Grant No.21JK0967)。
文摘Freeze-thaw cycles(FTCs)have an important effect on soil aggregate stability by altering soil structures,thereby influencing soil wind and water erosion on the eastern Qinghai-Tibet Plateau.However,the effects of FTCs on the stability of these soils remain unclear.Here,we conducted freeze-thaw simulations in laboratory to investigate the effects of FTCs(0 to 15 cycles)on the wet-and dry-sieving aggregate stability of undisturbed sandy loam from Maqu county,which was treated with different initial soil moisture contents(1%to 25%in increments of 4%)and initial aggregate diameters(<2,2-5,5-10,and 10-15 mm).Results show that soil aggregates with initial diameters larger than 2 mm exhibit higher soil organic carbon contents(1.45%-1.57%)and silt contents(34.63%-35.52%)than those smaller than 2 mm(0.93%and 31.38%,respectively).The stability of both wet-and dry-sieving aggregates increases with larger initial diameters.Increasing initial soil moisture content from 1%to 25%reduces aggregate stability,with reductions of 2.4%-88.0%for wet-sieving aggregates and 2.1%-25.5%for dry-sieving aggregates(>2 mm).With increasing FTCs,wet-sieving aggregate(>2 mm)stability exhibits a fluctuating upward trend,with increases of 79.2%-87.4%after 15 FTCs,while dry-sieving aggregate(>2 mm)stability decreases significantly(5.7%-21.7%)upon the first FTC and remains unchanged thereafter.The stability of both the wet-and dry-sieving aggregates smaller than 2 mm remains unchanged with increasing FTCs(p>0.05).SOC content decreases by 22.3%on average with increasing FTCs from 1 to 15 and shows no significant correlations with wet-and dry-sieving aggregate stability.Higher silt content(r=0.39,p<0.05)and lower sand content(r=-0.38,p<0.05)enhances the wet-sieving aggregate stability of sandy loam.Frequent FTCs tend to improve wet-sieving aggregate stability but reduce dry-sieving aggregate stability in the sandy loam.The findings provide certain guidance for preventing freeze-thaw-induced wind erosion.
基金supported by the Guangdong Basic and Applied Basic Research Foundation,China(No.2021B1515140007).
文摘The rapid cycling synchrotron(RCS)at the China spallation neutron source operates as a high-intensity proton accelerator.The coupled bunch instability was observed during RCS beam commissioning,which significantly limited the beam power.To investigate the dynamics of instability under an increased beam power,a pulsed octupole magnet with a gradient of 900 T/m^(3) was developed.The magnet system integrated an octupole magnet with a pulsed power supply.The field was carefully measured to examine the performance before its installation into the tunnel.After the installation of the magnets,beam measurements were performed to confirm the effectiveness of the instability mitigation on an actual proton beam.The measurement results show that the instability can be suppressed using the pulsed octupole magnet,particularly at the highenergy stage in an acceleration cycle,meeting the requirements for stable operation of the accelerator.Additionally,when the instability is completely suppressed through chromaticity optimization,octupole magnets can significantly enhance the RCS transmission efficiency,which is crucial for controlling beam loss.The pulsed octupole magnet offers significant progress in beam stability in the RCS,providing valuable experience for further beam power enhancement.
基金supported by the China Medical University Hospital,Department of Medical Research(DMR-110-209)the Ministry of Science and Technology,Taiwan(MOST:109-2320-B-303-001-MY2),CMU107-ASIA-08,CMU109-MF-76 and CMU105-ASIA-01Taichung Armed Forces General Hospital:TCAFGH_D_115034.
文摘Objective:MicroRNAs(miRNAs)are small,non-coding RNAs that play a key role in the development of chemoresistance in various cancer types,including colorectal cancer(CRC).In this study,we aimed to study the underlying mechanisms of miRNA in chemotherapy-resistant CRC.Methods:LoVo CRC cell line was exposed to oxaliplatin at an increased dose,and cells were cultured in the presence of oxaliplatin to develop LoVo^(OXR) cells.Microarray and Quantitative Reverse Transcription Polymerase Chain Reaction(qRT-PCR),western blot,and transwell assay were used to evaluate the chemoresistance in LoVo^(OXR) CRC cells.Results:Microarray and qRT-PCR analysis showed an increased expression of miR-100-5p in LoVo^(OXR) cells.MTT assay and flow cytometry analysis revealed less apoptosis and higher cell viability in LoVo^(OXR) cells.mRNA prediction target gene analysis showed C-terminal domain small phosphatase-like(CTDSPL),a phosphatase-like tumor suppressor,as a key target of miR-100-5p.CTDSPL expression was low in LoVo^(OXR) cells compared to LoVoWT cells.miR-100-5p regulates G1/S and S-phase transitions and inhibits differentiation by targeting the CTDSPL/pRB/E2F1 signaling pathway,which involves the modulation of cell cycle effectors in LoVo^(OXR) cells.Further,we found that forkhead box P3(FOXP3),as the upstream target of miR-100-5p,is highly expressed in LoVo^(OXR) cells.Inhibiting miR-100-5p and FOXP3 down-regulates miR-100-5p expression,while increased CTDSPL expression contributed to reduced cell proliferation and promoted cell apoptosis in LoVo^(OXR) CRC cells.Conclusions:miR-100-5p plays an oncogenic role in inducing chemoresistance through modulation of the CTDSPL/retinoblastoma protein(pRB)/E2F transcription factor 1(E2F1)axis in CRC cells.
文摘Cell cycle kinetic activity in the cortical cells of the lentil (Lens culinaris Me-die. cv. Verte du Puy) primary root during germination was examined both temporally and spatially. Immunohistochemical and cytological evidence indicated that DNA replication and cell division started in the cortical cells of tire lentil primary root after around 13 and 17 h of imbibition, respectively. The first cells in DNA synthesis and the First mitotic figures all appeared in the cortical cells about I mm front the root-cap junction, but these divided cells had synthesized their DNA during the maturity of seed instead of during germination. The kinetic pattern of activity of the first cell cycle showed that these cells were not activated synchronously, but re-entered the cell cycle in turn depending on their places in the root tip, However, the adjacent cells partially synchronously proceeded their cell cycle.
