Objective:To investigate the clinical efficacy and safety of percutaneous kyphoplasty at different surgical timings in the treatment of osteoporotic vertebral compression fracture(OVCF)based on the theory of“dynamic-...Objective:To investigate the clinical efficacy and safety of percutaneous kyphoplasty at different surgical timings in the treatment of osteoporotic vertebral compression fracture(OVCF)based on the theory of“dynamic-static integration”.Methods:Patients with OVCF who underwent percutaneous kyphoplasty in our hospital were selected and divided into Groups A,B,and C for those undergoing surgery within 7,7—21,and>21 days of fracture occurrence.The variations in the amount of bone cement injected,pre-and post-operative pain levels,functional activity,deformity correction of the injured vertebrae,bone cement leakage,and vertebral body height loss were compared among the three groups.Results:Regarding pain relief and functional activity,the postoperative Visual Analog Scale and Oswestry Disability Index scores of the three groups significantly improved.Furthermore,the deformities of the injured vertebrae in the three groups were significantly corrected,with Groups A and B exhibiting superior correction compared to Group C.Moreover,the bone cement leakage rates in groups A and C were higher than that in Group B.At the 3-month follow-up,the loss of vertebral height in Group C was significantly higher than those in groups A and B.Conclusion:Kyphoplasty is effective for OVCF treatment.Early surgery can effectively restore the vertebral height of the injured vertebra,reduce kyphosis,and reduce height loss of the injured vertebra after surgery;nevertheless,treatment within 1—3 weeks of the fracture can reduce the occurrence of bone cement leakage,making the surgery safer.Therefore,surgical treatment within 1—3 weeks of fracture is safer and can achieve satisfactory therapeutic effects.From the perspective of traditional Chinese medicine,PKP surgery can transform the fracture end from a micromotion state to a fixed state,which fully embodies the theory of“dynamic-static integration”.展开更多
After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the tim...After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the timing of interventions,combined with the limitations of current methods.To address these challenges,various techniques have been developed to aid in the repair and reconstruction of neural circuits at different stages of injury.Notably,neuromodulation has garnered considerable attention for its potential to enhance nerve regeneration,provide neuroprotection,restore neurons,and regulate the neural reorganization of circuits within the cerebral cortex and corticospinal tract.To improve the effectiveness of these interventions,the implementation of multitarget early interventional neuromodulation strategies,such as electrical and magnetic stimulation,is recommended to enhance functional recovery across different phases of nerve injury.This review concisely outlines the challenges encountered following spinal cord injury,synthesizes existing neurostimulation techniques while emphasizing neuroprotection,repair,and regeneration of impaired connections,and advocates for multi-targeted,task-oriented,and timely interventions.展开更多
体例要求1.注释采用脚注、每页排序方式,编号加圈,逐一注明文中引用或参考的资料数据出处。2.中文注释采用宋体小五号,外文注释采用Times New Roman小五号。3.英文注释中的著作和文章名首字母大写,动词、名词、形容词等实词首字母大写,...体例要求1.注释采用脚注、每页排序方式,编号加圈,逐一注明文中引用或参考的资料数据出处。2.中文注释采用宋体小五号,外文注释采用Times New Roman小五号。3.英文注释中的著作和文章名首字母大写,动词、名词、形容词等实词首字母大写,介词、连词、冠词字母小写。4.网络材料应是研究机构、国际组织/机构、行业或专业组织/机构、政府等官方网站的权威材料,并须标注投稿时能够访问的有效网址。展开更多
This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relativ...This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.展开更多
Drought influences carbon fixation by plants.Therefore,elucidating its impact on carbon fluxes in plants at the ecosystem level is crucial for assessing their role in mitigating climate change.Using carbon fluxes and ...Drought influences carbon fixation by plants.Therefore,elucidating its impact on carbon fluxes in plants at the ecosystem level is crucial for assessing their role in mitigating climate change.Using carbon fluxes and environmental factor data from FLUXNET sites,we analyzed the influence of drought on carbon fluxes,their drivers,time-lag effects,and recovery times across various climatic regions and seasons.Results showed drought significantly decreased gross primary production(GPP),ecosystem respiration,and net ecosystem productivity in arid regions but slightly increased carbon sequestration in humid regions.Summer droughts negatively affected vegetation carbon fluxes,partly offset by the positive impact of spring droughts.Nonforest carbon fluxes were more susceptible to drought effects than forest fluxes.Soil water content(SWC)was the main influence on changes in arid regions,whereas vapor pressure deficit(VPD)dominated humid regions.Decreased SWC and increased VPD reduced carbon sequestration in arid regions but increased it in humid regions.Increased VPD reduced GPP,leading to forest carbon loss,whereas decreased SWC reduced GPP,leading to nonforest carbon loss.The lag time of the drought effects on carbon fluxes was longer in humid regions(19.44 d)than in arid regions(14.71 d).Compared to nonforest areas(16.74 d and 57 d for drought lag and recovery time,respectively),forest areas had a longer lag(18.81 d)and recovery time(92 d).The findings revealed discrepancies in the main factors regulating vegetation carbon fluxes during droughts between arid and humid regions and between forest and nonforest ecosystems.These insights provide a new perspective on understanding and simulating carbon-climate feedback.Enhancing ecosystem diversity is a feasible measure to increase drought resistance.展开更多
AIM:To compare the tear film quantity and stability parameters in keratoconus(KCN)and normal eyes using test breakup time(TBUT),noninvasive TBUT(NITBUT),and Schirmer test.METHODS:All participants(n=166),including pati...AIM:To compare the tear film quantity and stability parameters in keratoconus(KCN)and normal eyes using test breakup time(TBUT),noninvasive TBUT(NITBUT),and Schirmer test.METHODS:All participants(n=166),including patients with KCN and age-matched healthy individuals with normal corneas,were recruited from those referred to Farabi Eye Hospital,Iran,in 2023.To better account for genetic and environmental factors,the control group comprised healthy individuals who were relatives of KCN patients and had normal corneal topography.Tear quantity parameters were evaluated in the following order:NITBUT,TBUT,and Schirmer tests.RESULTS:The mean age of cases in KCN(61.7%males)and normal(63.5%males)participants was 27.54±5.44y(range 19 to 38)and 27.52±5.63y(range 20 to 38),respectively(P=0.976).NIBUT,TBUT,and Schirmer’s tests were significantly lower in KCN group compared to normal controls(all P<0.001).The mean difference for NIBUT was-7.81s(P<0.001),and for TBUT was-7.61s(P<0.001).Schirmer test values were also significantly lower in the KCN group,with a mean difference of-5.61 mm compared to normal people(P<0.001).CONCLUSION:Our findings demonstrate significant tear film impairment in KCN.The reductions in NIBUT,TBUT and Schirmer scores highlight an underlying tear film dysfunction in KCN that extends beyond the morphological changes of the cornea.展开更多
Hard disk drives(HDDs)serve as the primary storage devices in modern data centers.Once a failure occurs,it often leads to severe data loss,significantly degrading the reliability of storage systems.Numerous studies ha...Hard disk drives(HDDs)serve as the primary storage devices in modern data centers.Once a failure occurs,it often leads to severe data loss,significantly degrading the reliability of storage systems.Numerous studies have proposed machine learning-based HDD failure prediction models.However,the Self-Monitoring,Analysis,and Reporting Technology(SMART)attributes differ across HDD manufacturers.We define hard drives of the same brand and model as homogeneous HDD groups,and those from different brands or models as heterogeneous HDD groups.In practical engineering scenarios,a data center is often composed of a heterogeneous population of HDDs,spanning multiple vendors and models.Existing research predominantly focuses on homogeneous datasets,ignoring the model’s generalization capability across heterogeneous HDDs.As a result,HDD models with limited samples often suffer from poor training effectiveness and prediction performance.To address this issue,we investigate generalizable SMART predictors across heterogeneous HDD groups.By extracting time-series features within a fixed sliding time window,we propose a Heterogeneous Disk Failure Prediction Method based on Time Series Features(HDFPM)framework.This method is adaptable to HDD models with limited sample sizes,thereby enhancing its applicability and robustness across diverse drive populations.Experimental results show that the proposed model achieves an F1-score of 0.9518 when applied to two different Seagate HDD models,while maintaining the False Positive Rate(FPR)below 1%.After incorporating the Complexity-Ratio Dynamic Time Warping(CDTW)based feature enhancement method,the best prediction model achieves a True Positive Rate(TPR)of up to 0.93 between the two models.For next-day failure prediction across various Seagate models,the model achieves an F1-score of up to 0.8792.Moreover,the experimental results also show that within the same brand,the higher the proportion of shared SMART attributes across different models,the better the prediction performance.In addition,HDFPMdemonstrates the best stability andmost significant performance in heterogeneous environments.展开更多
1.(选择性必修一P2)Sometimes the smell alone can do the trick(奏效,起作用,达到目的),not to mention the lovely creamy flavour, which works like a time machine immediately transporting me back to my sunny childhood.
Chilo suppressalis(Walker)is one of the most important rice pests worldwide,posing a significant challenge to effective control.To develop a precision-timed,eco-friendly management strategy,overwintering population in...Chilo suppressalis(Walker)is one of the most important rice pests worldwide,posing a significant challenge to effective control.To develop a precision-timed,eco-friendly management strategy,overwintering population investigation and dynamic monitoring of C.suppressalis populations were conducted in the Meishan region of Sichuan,China,from 2023 to 2024.The optimal timing for insecticide application was estimated,followed by field trials evaluating the efficacy of different insecticides.Results demonstrated that the peak emergence of first-generation adults typically occurred in early July(under the environmental conditions of the Meishan region),with the ambient humidity below 75%and temperature around 29◦C.Pesticide efficacy trials show that insecticide combinations exhibited superior control.Notably,a combined treatment of emamectin benzoate⋅methoxyfenozide+chlorantraniliprole achieved the highest control efficacy(90.05%)and a corresponding yield of 12,491.55 kg/ha.All tested treatments were determined to be safe for rice growth.Furthermore,this optimized strategy resulted in notable economic benefits,including a 50%reduction in pesticide usage and cost savings of 4796.15 CNY compared to conventional practices.This study provides valuable insights into sustainable rice production and pest management and,for the first time,proposes a precision application time window based on intelligent monitoring.展开更多
To address the key scientific challenge of monitoring the dynamic fracturing of surrounding rock in deep roadways,this study systematically investigates the quantitative relationship between stress and charge signals ...To address the key scientific challenge of monitoring the dynamic fracturing of surrounding rock in deep roadways,this study systematically investigates the quantitative relationship between stress and charge signals during coal mass loading.By integrating innovative analytical approaches,introducing quantitative evaluation indices,and developing a charge–stress inversion model,and incorporating underground monitoring practices,significant progress has been achieved in elucidating the correlation between stress variations and charge signals throughout the entire coal mass fracturing process.First,in the field of stress–charge correlation analysis,empirical mode decomposition(EMD)was combined with wavelet coherence analysis for the first time,enabling the removal of slow-varying stress trends while retaining high-frequency fluctuations.This approach allowed for the quantitative characterization of the evolution of coherence between stress variations and charge fluctuations across multiple time scales.Second,coherence skewness and the proportion of high-coherence intervals were innovatively introduced to examine the influence of time scale selection on correlation results.On this basis,a criterion for determining the near-optimal observation scale of charge signals was proposed,providing a quantitative reference for time scale selection in similar signal analyses.Finally,by correlating charge signals with coal damage factors and stress states,a charge-based damage evolution equation was established to achieve effective stress inversion.Combined with in situ monitoring of stress and charge in roadway surrounding rock,this approach revealed the correlation characteristics of stress and charge intensity responses during the dynamic fracturing process.The results indicate,first,that charge signals are not significantly correlated with the absolute stress level of coal but are directly associated with stress variations following coal damage and failure,with the amplitude of charge fluctuations increasing alongside stress fluctuations.Second,coherence between stress and charge signals varies markedly across time scales,with excessively small or large scales leading to distortion,and the scale corresponding to the peak proportion of intervals with coherence>0.8 was identified as the near-optimal observation scale.Third,charge signals can effectively characterize coal damage factors,and the established damage evolution equation can effectively invert stress variation trends.Fourth,in underground roadways,zones of dynamic fracturing in surrounding rock are commonly located in areas where stress concentration overlaps with regions of high charge intensity,further confirming the strong consistency between charge and stress variations.These findings improve the theoretical framework of charge signal responses in loaded coal and provide a scientific basis for precise“stress-charge”monitoring of dynamic disasters,offering practical potential for engineering applications.展开更多
Flowering time is a critical agronomic trait with a profound effect on the productivity and adaptabillity of rapeseed(Brassica napus L.).Strategically advancing flowering time can reduce the risk of yield losses due t...Flowering time is a critical agronomic trait with a profound effect on the productivity and adaptabillity of rapeseed(Brassica napus L.).Strategically advancing flowering time can reduce the risk of yield losses due to extreme climatic conditions and facilitate the cultivation of subsequent crops on the same land,thereby enhancing overall agricultural efficiency.In this review,we synthesize current information on flowering time regulation in rapeseed through an integrated analysis of its genetic,hormonal,and environmental dimensions,emphasizing their crosstalk and implications for yield.We consolidate multi-omics evidence from population genetics,functional genomics,and systems biology to create a haplotype-based framework that overcomes the trade-off between flowering time and yield,providing support for the precision breeding of early-maturing cultivars.The insights presented here could inform future research on flowering time regulation and guide strategies for increasing rapeseed productivity.展开更多
This research is focused on the calculation of a reasonable detonator delay time for realizing cut blast vibration control.First,the viscoelastic rock mass parameters corresponding to the engineering rock mass quality...This research is focused on the calculation of a reasonable detonator delay time for realizing cut blast vibration control.First,the viscoelastic rock mass parameters corresponding to the engineering rock mass quality classification were determined based on wave theory of Kelvin medium.Then,a calculation model was obtained for the millisecond-delay cut blast vibration in Kelvin media using the Starfield charge superposition principle.Further,the influence of the delay time on the cut blast vibration was quantitatively analyzed and a method for calculating the reasonable cut blasting millisecond delay time is proposed according to the principle of dimensional analysis.Finally,field tests were used to verify the applicability of the method.The results show that 5 ms to 20 ms is a better detonator delay time range and cut blasting vibration can be effectively controlled using the delay time calculated by the calculation model described in this paper.展开更多
The Shanghai High Repetition Rate XFEL and Extreme Light Facility(SHINE)is currently under construction as one of the world’s most advanced hard X-ray free-electron laser facilities.The timing system,as an essential ...The Shanghai High Repetition Rate XFEL and Extreme Light Facility(SHINE)is currently under construction as one of the world’s most advanced hard X-ray free-electron laser facilities.The timing system,as an essential part of the free-electron laser facility,provides precise timing of trigger pulse signals for a range of devices to ensure that particles are generated and accelerated to the designed energy while enabling the precise measurement of beam parameters.To precisely distribute and synchronize the 1.003086 MHz(1300/1296)timing signals over a distance of approximately 3.1 km based on White Rabbit technology,three technical routes have been proposed.This paper begins with a description of the design and development process of the timing system for the SHINE project,which culminates with the determination of the design scheme.During the installation and commissioning of the timing system,the jitter accuracy of the timing signal was tested and found to be less than 10 ps,which meets the requirements of the project.Furthermore,the precise clock synchronization signal provided by the timing system supported the joint debugging of various related systems and realization of beam acquisition.展开更多
Peri-urban plantations in the Mediterranean are often degraded due to human inactivity and climate change,leading to a loss of ecosystem services and biodiversity.This study investigates the impact of different thinni...Peri-urban plantations in the Mediterranean are often degraded due to human inactivity and climate change,leading to a loss of ecosystem services and biodiversity.This study investigates the impact of different thinning practices on carbon sequestration and tree stability in a degraded periurban plantation in the Italian Apennines,six years after thinning.Three treatments were compared:(a)moderate thinning from below(-25%biomass),representing the typical practice;(b)intense selective thinning(-35%biomass),representing an innovative approach;and(c)no management as the control.Growth projections were used to estimate carbon recovery for these treatments,based on site-specific models calibrated with real data.The results show that both thinning approaches increased carbon sequestration over time,with the innovative thinning achieving a 7%higher annual carbon sequestration rate than traditional thinning and 8%more than the control.Estimated payback times were9 years for recovering the harvested volume in both thinning approaches,10 years for innovative thinning to surpass traditional thinning,17 years for innovative thinning to surpass the control,and 24 years for traditional thinning to surpass the control.Additionally,tree mechanical stability improved significantly in both thinning treatments after two years,with further increases observed in the innovative thinning group after six years.These results suggest that selective thinning can accelerate forest recovery and carbon sequestration,especially in areas with high stem density,where it can reduce the negative impacts of tree mortality and deadwood accumulation.However,careful planning is required to mitigate potential short-term stability is sues,particularly in challenging environments(e.g.,windy conditions,steep slopes).Forest management strategies should therefore aim to balance growth,carbon storage,and tree stability,considering both long-term sustainability and local environmental conditions.The findings are particularly relevant for current climate change mitigation strategies,emphasizing that thinning should be carefully tailored to forest type and conditions to maximize benefits in carbon credit generation and sustainable forest management practices.展开更多
Field-effect nanofluidic transistors(FENTs),biomimicking the structure and functionality of neuron,act as biological transistors with the ability to gate switching responses to external stimuli.The switching ratio has...Field-effect nanofluidic transistors(FENTs),biomimicking the structure and functionality of neuron,act as biological transistors with the ability to gate switching responses to external stimuli.The switching ratio has been verified to evaluate the performance of FENTs,but until recently,the response time,another crucial indicator,has been ignored.Employing finite-element method,we investigated the relationship among gate charge,switching ratio and response time by divisionally manipulating gate charge,including entrance surface and the surface of confinement space,for ion transport to optimize switching capability.The dual-split gate charge on FENTs exhibits synergistic effect on switching response.Based on the two regional gate charge on FENTs,multivalence ions in lower concentration,high aspect ratio and single channel show higher switching ratio but longer response time compared to monovalent ions.The findings highlight the necessity of balancing these two signals in FENTs and offer insights for optimizing their design and expanding applications to dual-signal-detection iontronics.展开更多
Considering the impact of terminal impact time constraints and the state information of maneuvering targets on the guidance accuracy in multi-UAV cooperative guidance,this paper proposes an impact time cooperative con...Considering the impact of terminal impact time constraints and the state information of maneuvering targets on the guidance accuracy in multi-UAV cooperative guidance,this paper proposes an impact time cooperative control guidance law(ITCCG)that combines the optimal error dynamics with an improved adaptive cubature Kalman filter(IACKF)algorithm.First,a terminal impact time feedback term is introduced into proportional navigation guidance based on the relative virtual guidance model,and terminal time control is achieved through optimal error dynamics.Then,the Huber loss function is used to reduce the impact of measurement outliers,and the diagonal decomposition is applied to address the issue of non-positive definite matrices that cannot undergo Cholesky decomposition.Finally,the ITCCG and IACKF algorithms combined achieve multi-UAV time-cooperated guidance based on maneuvering target state estimation.Simulation results show that the proposed algorithm effectively reduces the target state estimation error and achieves cooperative guidance within the desired time frame.展开更多
Sichuan sausages with moisture contents of 40%,45%,50%,and 60% were stored at-18℃for durations of 0,2,4,6,and 8 weeks to evaluate the effect of moisture content on the quality attributes of Sichuan sausages during fr...Sichuan sausages with moisture contents of 40%,45%,50%,and 60% were stored at-18℃for durations of 0,2,4,6,and 8 weeks to evaluate the effect of moisture content on the quality attributes of Sichuan sausages during frozen storage.Product indicators including pH,colour,thiobarbituric acid reactive substances(TBARS),total volatile basic nitrogen(TVB-N),texture,electronic nose(E-nose)response,and water-holding capacity(thawing and cooking losses)were determined.The results indicated that as storage time increased,water retention in Sichuan sausages with different moisture contents decreased,while the degree of protein and lipid oxidation increased.This led to an increase in pH value,a colour shift from red-bright to grey-brown,and a deterioration in palatability.Among the samples,sausages with 50% moisture content exhibited the lowest thawing and cooking losses,indicating superior water-holding capacity.After 8 weeks of storage,TBARS and TVB-N values for the 50% moisture group were 19.5%and 2.5%lower,respectively,than those of the 40%and 45%moisture groups,indicating a reduced degree of oxidation.Furthermore,Sichuan sausage with 50%moisture content demonstrated an appropriate pH and colour difference,along with excellent texture and flavour,as evidenced by its higher toughness and satisfactory hardness.In conclusion,Sichuan sausage with 50% moisture content demonstrated the highest overall quality under frozen storage conditions.展开更多
Speckle-based optical cryptosystems are promising technologies for information security.However,existing techniques mostly rely on digital decryption,resulting in computational delay and undermining the high-speed adv...Speckle-based optical cryptosystems are promising technologies for information security.However,existing techniques mostly rely on digital decryption,resulting in computational delay and undermining the high-speed advantage of optical encryption.Moreover,conventional neural networks are typically effective only on images from the same distribution as the training datasets,limiting their general applicability.In this paper,we propose an all-optical high-speed decryption scheme for real-time recovery of speckle-encoded ciphertexts.By constructing a physics-informed diffractive neural network that approximates the inverse transmission matrix of the scattering medium,secret images can be directly reconstructed from speckle fields without optoelectronic conversion or post-processing.The network is trained with only 2048 samples from the MNIST dataset.Its transfer learning capability is validated across three out-of-distribution datasets,with decrypted images achieving a Pearson correlation coefficient of 0.82 and a structural similarity index measure of 0.75,demonstrating excellent transfer learning capability.For the first time,to our knowledge,this scheme simultaneously overcomes the bottlenecks of decryption delay and limited network generalizability in conventional speckle-based cryptosystems,achieving real-time image decryption with strong transferability.It provides a new pathway for developing low-power,real-time,and broadly applicable optical encryption systems,demonstrating significant potential for applications in high-speed security optical communications.展开更多
To study the influence of support timing and support strength on the mechanical properties and deformation damage characteristics of a single-sided unloaded rock mass,a true triaxial perturbation unloaded rock testing...To study the influence of support timing and support strength on the mechanical properties and deformation damage characteristics of a single-sided unloaded rock mass,a true triaxial perturbation unloaded rock testing system was used to conduct rock damage tests on sandstone with different support timing and strength paths.Based on the acoustic emission monitoring system,the spatial and temporal evolution characteristics of the whole process of rock body loaded instability under two stress paths were studied,and the mechanism of the reinforcing effect of stress support on the unloaded rock mass was analyzed.The results show that,within the scope of this study,both earlier applications of shoring and an increase in shoring strength can effectively improve the ultimate bearing capacity of the unloaded rock,which increases the ultimate bearing capacity of the unloaded rock mass by 60.31% and 54.96%,respectively;There is a phenomenon of rebound deformation of the rock mass during sudden changes in stress(single-sided unloading,stress support),which shows opposite expansion and compression platforms on the stress−strain curve;The crack evolution of unloaded rock under different stress support conditions shows the state law of"initial crack activation→middle steady state expansion→late main crack penetration",and the lagging support significantly accelerates the crack evolution from local activation to main penetration;The single-sided unloading and stress-supporting stages have less influence on the unloading deformationsσ_(1u),σ_(2u) and support deformationsσ_(1) t,σ_(2t) in theσ_(1) andσ_(2)directions,while they show significant response characteristics toσ_(3u),σ_(vu) and σ_(3) t,σ_(vt),and with the increase of the support strength,the stress-supporting stagesσ_(3) t,σ_(vt) gradually increase and exceed the deformations generated by the unloading stagesσ_(3u),σ_(vu);The increase of support strength can effectively compensate for the rock stress loss caused by unloading,which makes the maximum,minimum,and volumetric strain support coefficients during the loading and unloading of the rock body increase gradually while the effect on the intermediate principal strain support coefficient is small;During loading,the support strength of rock masses seeks a new bearing area by regulating stress equilibrium states.This process primarily manifests as a shift in the locations of the crushing zone and the main bearing area,accompanied by a corresponding transformation in failure patterns.Consequently,the rock mass transitions from asymmetric three-zone damage under no or weak support to approximate symmetric three-zone damage under strong support.Simultaneously,the main load-bearing area of the rock mass shifts from deep bearing in the unsupported to middle bearing under strong support as the support strength increases.展开更多
基金supported by the National Natural Science Foundation of China(82374493).
文摘Objective:To investigate the clinical efficacy and safety of percutaneous kyphoplasty at different surgical timings in the treatment of osteoporotic vertebral compression fracture(OVCF)based on the theory of“dynamic-static integration”.Methods:Patients with OVCF who underwent percutaneous kyphoplasty in our hospital were selected and divided into Groups A,B,and C for those undergoing surgery within 7,7—21,and>21 days of fracture occurrence.The variations in the amount of bone cement injected,pre-and post-operative pain levels,functional activity,deformity correction of the injured vertebrae,bone cement leakage,and vertebral body height loss were compared among the three groups.Results:Regarding pain relief and functional activity,the postoperative Visual Analog Scale and Oswestry Disability Index scores of the three groups significantly improved.Furthermore,the deformities of the injured vertebrae in the three groups were significantly corrected,with Groups A and B exhibiting superior correction compared to Group C.Moreover,the bone cement leakage rates in groups A and C were higher than that in Group B.At the 3-month follow-up,the loss of vertebral height in Group C was significantly higher than those in groups A and B.Conclusion:Kyphoplasty is effective for OVCF treatment.Early surgery can effectively restore the vertebral height of the injured vertebra,reduce kyphosis,and reduce height loss of the injured vertebra after surgery;nevertheless,treatment within 1—3 weeks of the fracture can reduce the occurrence of bone cement leakage,making the surgery safer.Therefore,surgical treatment within 1—3 weeks of fracture is safer and can achieve satisfactory therapeutic effects.From the perspective of traditional Chinese medicine,PKP surgery can transform the fracture end from a micromotion state to a fixed state,which fully embodies the theory of“dynamic-static integration”.
基金supported by the National Key Research and Development Program of China,No.2023YFC3603705(to DX)the National Natural Science Foundation of China,No.82302866(to YZ).
文摘After spinal cord injury,impairment of the sensorimotor circuit can lead to dysfunction in the motor,sensory,proprioceptive,and autonomic nervous systems.Functional recovery is often hindered by constraints on the timing of interventions,combined with the limitations of current methods.To address these challenges,various techniques have been developed to aid in the repair and reconstruction of neural circuits at different stages of injury.Notably,neuromodulation has garnered considerable attention for its potential to enhance nerve regeneration,provide neuroprotection,restore neurons,and regulate the neural reorganization of circuits within the cerebral cortex and corticospinal tract.To improve the effectiveness of these interventions,the implementation of multitarget early interventional neuromodulation strategies,such as electrical and magnetic stimulation,is recommended to enhance functional recovery across different phases of nerve injury.This review concisely outlines the challenges encountered following spinal cord injury,synthesizes existing neurostimulation techniques while emphasizing neuroprotection,repair,and regeneration of impaired connections,and advocates for multi-targeted,task-oriented,and timely interventions.
文摘体例要求1.注释采用脚注、每页排序方式,编号加圈,逐一注明文中引用或参考的资料数据出处。2.中文注释采用宋体小五号,外文注释采用Times New Roman小五号。3.英文注释中的著作和文章名首字母大写,动词、名词、形容词等实词首字母大写,介词、连词、冠词字母小写。4.网络材料应是研究机构、国际组织/机构、行业或专业组织/机构、政府等官方网站的权威材料,并须标注投稿时能够访问的有效网址。
文摘This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.
基金supported by the National Natural Science Foundation of China(grant no.32371866)。
文摘Drought influences carbon fixation by plants.Therefore,elucidating its impact on carbon fluxes in plants at the ecosystem level is crucial for assessing their role in mitigating climate change.Using carbon fluxes and environmental factor data from FLUXNET sites,we analyzed the influence of drought on carbon fluxes,their drivers,time-lag effects,and recovery times across various climatic regions and seasons.Results showed drought significantly decreased gross primary production(GPP),ecosystem respiration,and net ecosystem productivity in arid regions but slightly increased carbon sequestration in humid regions.Summer droughts negatively affected vegetation carbon fluxes,partly offset by the positive impact of spring droughts.Nonforest carbon fluxes were more susceptible to drought effects than forest fluxes.Soil water content(SWC)was the main influence on changes in arid regions,whereas vapor pressure deficit(VPD)dominated humid regions.Decreased SWC and increased VPD reduced carbon sequestration in arid regions but increased it in humid regions.Increased VPD reduced GPP,leading to forest carbon loss,whereas decreased SWC reduced GPP,leading to nonforest carbon loss.The lag time of the drought effects on carbon fluxes was longer in humid regions(19.44 d)than in arid regions(14.71 d).Compared to nonforest areas(16.74 d and 57 d for drought lag and recovery time,respectively),forest areas had a longer lag(18.81 d)and recovery time(92 d).The findings revealed discrepancies in the main factors regulating vegetation carbon fluxes during droughts between arid and humid regions and between forest and nonforest ecosystems.These insights provide a new perspective on understanding and simulating carbon-climate feedback.Enhancing ecosystem diversity is a feasible measure to increase drought resistance.
文摘AIM:To compare the tear film quantity and stability parameters in keratoconus(KCN)and normal eyes using test breakup time(TBUT),noninvasive TBUT(NITBUT),and Schirmer test.METHODS:All participants(n=166),including patients with KCN and age-matched healthy individuals with normal corneas,were recruited from those referred to Farabi Eye Hospital,Iran,in 2023.To better account for genetic and environmental factors,the control group comprised healthy individuals who were relatives of KCN patients and had normal corneal topography.Tear quantity parameters were evaluated in the following order:NITBUT,TBUT,and Schirmer tests.RESULTS:The mean age of cases in KCN(61.7%males)and normal(63.5%males)participants was 27.54±5.44y(range 19 to 38)and 27.52±5.63y(range 20 to 38),respectively(P=0.976).NIBUT,TBUT,and Schirmer’s tests were significantly lower in KCN group compared to normal controls(all P<0.001).The mean difference for NIBUT was-7.81s(P<0.001),and for TBUT was-7.61s(P<0.001).Schirmer test values were also significantly lower in the KCN group,with a mean difference of-5.61 mm compared to normal people(P<0.001).CONCLUSION:Our findings demonstrate significant tear film impairment in KCN.The reductions in NIBUT,TBUT and Schirmer scores highlight an underlying tear film dysfunction in KCN that extends beyond the morphological changes of the cornea.
基金supported by the Tianjin Manufacturing High Quality Development Special Foundation(No.20232185)the Roycom Foundation(No.70306901).
文摘Hard disk drives(HDDs)serve as the primary storage devices in modern data centers.Once a failure occurs,it often leads to severe data loss,significantly degrading the reliability of storage systems.Numerous studies have proposed machine learning-based HDD failure prediction models.However,the Self-Monitoring,Analysis,and Reporting Technology(SMART)attributes differ across HDD manufacturers.We define hard drives of the same brand and model as homogeneous HDD groups,and those from different brands or models as heterogeneous HDD groups.In practical engineering scenarios,a data center is often composed of a heterogeneous population of HDDs,spanning multiple vendors and models.Existing research predominantly focuses on homogeneous datasets,ignoring the model’s generalization capability across heterogeneous HDDs.As a result,HDD models with limited samples often suffer from poor training effectiveness and prediction performance.To address this issue,we investigate generalizable SMART predictors across heterogeneous HDD groups.By extracting time-series features within a fixed sliding time window,we propose a Heterogeneous Disk Failure Prediction Method based on Time Series Features(HDFPM)framework.This method is adaptable to HDD models with limited sample sizes,thereby enhancing its applicability and robustness across diverse drive populations.Experimental results show that the proposed model achieves an F1-score of 0.9518 when applied to two different Seagate HDD models,while maintaining the False Positive Rate(FPR)below 1%.After incorporating the Complexity-Ratio Dynamic Time Warping(CDTW)based feature enhancement method,the best prediction model achieves a True Positive Rate(TPR)of up to 0.93 between the two models.For next-day failure prediction across various Seagate models,the model achieves an F1-score of up to 0.8792.Moreover,the experimental results also show that within the same brand,the higher the proportion of shared SMART attributes across different models,the better the prediction performance.In addition,HDFPMdemonstrates the best stability andmost significant performance in heterogeneous environments.
文摘1.(选择性必修一P2)Sometimes the smell alone can do the trick(奏效,起作用,达到目的),not to mention the lovely creamy flavour, which works like a time machine immediately transporting me back to my sunny childhood.
基金funded by the National Key R&D Project‘Innovation and Integration of Key Technologies for Integration of Agricultural Machinery and Agronomy in Weak Links of Hybrid Mid-season Rice in Hilly Areas of Southwest China’(2023YFD2301901).
文摘Chilo suppressalis(Walker)is one of the most important rice pests worldwide,posing a significant challenge to effective control.To develop a precision-timed,eco-friendly management strategy,overwintering population investigation and dynamic monitoring of C.suppressalis populations were conducted in the Meishan region of Sichuan,China,from 2023 to 2024.The optimal timing for insecticide application was estimated,followed by field trials evaluating the efficacy of different insecticides.Results demonstrated that the peak emergence of first-generation adults typically occurred in early July(under the environmental conditions of the Meishan region),with the ambient humidity below 75%and temperature around 29◦C.Pesticide efficacy trials show that insecticide combinations exhibited superior control.Notably,a combined treatment of emamectin benzoate⋅methoxyfenozide+chlorantraniliprole achieved the highest control efficacy(90.05%)and a corresponding yield of 12,491.55 kg/ha.All tested treatments were determined to be safe for rice growth.Furthermore,this optimized strategy resulted in notable economic benefits,including a 50%reduction in pesticide usage and cost savings of 4796.15 CNY compared to conventional practices.This study provides valuable insights into sustainable rice production and pest management and,for the first time,proposes a precision application time window based on intelligent monitoring.
基金supported by the Research Fund of the National Natural Science Foundation of China(No.52374205)the Fundamental Research Project of the Educational Department of Liaoning Province(No.JYTMS20230793)the Research Fund of the State Key Laboratory of Coal Resources and Safe Mining,CUMT(No.YJY-XD-2024-A-016).
文摘To address the key scientific challenge of monitoring the dynamic fracturing of surrounding rock in deep roadways,this study systematically investigates the quantitative relationship between stress and charge signals during coal mass loading.By integrating innovative analytical approaches,introducing quantitative evaluation indices,and developing a charge–stress inversion model,and incorporating underground monitoring practices,significant progress has been achieved in elucidating the correlation between stress variations and charge signals throughout the entire coal mass fracturing process.First,in the field of stress–charge correlation analysis,empirical mode decomposition(EMD)was combined with wavelet coherence analysis for the first time,enabling the removal of slow-varying stress trends while retaining high-frequency fluctuations.This approach allowed for the quantitative characterization of the evolution of coherence between stress variations and charge fluctuations across multiple time scales.Second,coherence skewness and the proportion of high-coherence intervals were innovatively introduced to examine the influence of time scale selection on correlation results.On this basis,a criterion for determining the near-optimal observation scale of charge signals was proposed,providing a quantitative reference for time scale selection in similar signal analyses.Finally,by correlating charge signals with coal damage factors and stress states,a charge-based damage evolution equation was established to achieve effective stress inversion.Combined with in situ monitoring of stress and charge in roadway surrounding rock,this approach revealed the correlation characteristics of stress and charge intensity responses during the dynamic fracturing process.The results indicate,first,that charge signals are not significantly correlated with the absolute stress level of coal but are directly associated with stress variations following coal damage and failure,with the amplitude of charge fluctuations increasing alongside stress fluctuations.Second,coherence between stress and charge signals varies markedly across time scales,with excessively small or large scales leading to distortion,and the scale corresponding to the peak proportion of intervals with coherence>0.8 was identified as the near-optimal observation scale.Third,charge signals can effectively characterize coal damage factors,and the established damage evolution equation can effectively invert stress variation trends.Fourth,in underground roadways,zones of dynamic fracturing in surrounding rock are commonly located in areas where stress concentration overlaps with regions of high charge intensity,further confirming the strong consistency between charge and stress variations.These findings improve the theoretical framework of charge signal responses in loaded coal and provide a scientific basis for precise“stress-charge”monitoring of dynamic disasters,offering practical potential for engineering applications.
基金supported by the National Key Research and Development Program of China(2022YFD1200400)the National Natural Science Foundation of China(32272111)+4 种基金Special fund for youth team of the Southwest Universities(SWU-XJPY202306)Chongqing Natural Science Foundation(CSTB2024NSCQLZX0012)Modern Agro-industry Technology Research System(CARS-12)Chongqing Modern Agricultural Industry Technology System(COMAITS202504)Biological Breeding-National Science and Technology Major Project(2022ZD04008).We sincerely appreciate the Plant Editors team for English language editing of the manuscript,which significantly improved its clarity and overall quality.
文摘Flowering time is a critical agronomic trait with a profound effect on the productivity and adaptabillity of rapeseed(Brassica napus L.).Strategically advancing flowering time can reduce the risk of yield losses due to extreme climatic conditions and facilitate the cultivation of subsequent crops on the same land,thereby enhancing overall agricultural efficiency.In this review,we synthesize current information on flowering time regulation in rapeseed through an integrated analysis of its genetic,hormonal,and environmental dimensions,emphasizing their crosstalk and implications for yield.We consolidate multi-omics evidence from population genetics,functional genomics,and systems biology to create a haplotype-based framework that overcomes the trade-off between flowering time and yield,providing support for the precision breeding of early-maturing cultivars.The insights presented here could inform future research on flowering time regulation and guide strategies for increasing rapeseed productivity.
基金National Natural Science Foundation of China under Grant Nos.51979205 and 51939008。
文摘This research is focused on the calculation of a reasonable detonator delay time for realizing cut blast vibration control.First,the viscoelastic rock mass parameters corresponding to the engineering rock mass quality classification were determined based on wave theory of Kelvin medium.Then,a calculation model was obtained for the millisecond-delay cut blast vibration in Kelvin media using the Starfield charge superposition principle.Further,the influence of the delay time on the cut blast vibration was quantitatively analyzed and a method for calculating the reasonable cut blasting millisecond delay time is proposed according to the principle of dimensional analysis.Finally,field tests were used to verify the applicability of the method.The results show that 5 ms to 20 ms is a better detonator delay time range and cut blasting vibration can be effectively controlled using the delay time calculated by the calculation model described in this paper.
基金supported by SHINE and Shanghai Municipal Science and Technology Major Project(No.2017SHZDZX02).
文摘The Shanghai High Repetition Rate XFEL and Extreme Light Facility(SHINE)is currently under construction as one of the world’s most advanced hard X-ray free-electron laser facilities.The timing system,as an essential part of the free-electron laser facility,provides precise timing of trigger pulse signals for a range of devices to ensure that particles are generated and accelerated to the designed energy while enabling the precise measurement of beam parameters.To precisely distribute and synchronize the 1.003086 MHz(1300/1296)timing signals over a distance of approximately 3.1 km based on White Rabbit technology,three technical routes have been proposed.This paper begins with a description of the design and development process of the timing system for the SHINE project,which culminates with the determination of the design scheme.During the installation and commissioning of the timing system,the jitter accuracy of the timing signal was tested and found to be less than 10 ps,which meets the requirements of the project.Furthermore,the precise clock synchronization signal provided by the timing system supported the joint debugging of various related systems and realization of beam acquisition.
基金supported initially by the LIFE FoResMit Project(LIFE14 CCM/IT/000905)。
文摘Peri-urban plantations in the Mediterranean are often degraded due to human inactivity and climate change,leading to a loss of ecosystem services and biodiversity.This study investigates the impact of different thinning practices on carbon sequestration and tree stability in a degraded periurban plantation in the Italian Apennines,six years after thinning.Three treatments were compared:(a)moderate thinning from below(-25%biomass),representing the typical practice;(b)intense selective thinning(-35%biomass),representing an innovative approach;and(c)no management as the control.Growth projections were used to estimate carbon recovery for these treatments,based on site-specific models calibrated with real data.The results show that both thinning approaches increased carbon sequestration over time,with the innovative thinning achieving a 7%higher annual carbon sequestration rate than traditional thinning and 8%more than the control.Estimated payback times were9 years for recovering the harvested volume in both thinning approaches,10 years for innovative thinning to surpass traditional thinning,17 years for innovative thinning to surpass the control,and 24 years for traditional thinning to surpass the control.Additionally,tree mechanical stability improved significantly in both thinning treatments after two years,with further increases observed in the innovative thinning group after six years.These results suggest that selective thinning can accelerate forest recovery and carbon sequestration,especially in areas with high stem density,where it can reduce the negative impacts of tree mortality and deadwood accumulation.However,careful planning is required to mitigate potential short-term stability is sues,particularly in challenging environments(e.g.,windy conditions,steep slopes).Forest management strategies should therefore aim to balance growth,carbon storage,and tree stability,considering both long-term sustainability and local environmental conditions.The findings are particularly relevant for current climate change mitigation strategies,emphasizing that thinning should be carefully tailored to forest type and conditions to maximize benefits in carbon credit generation and sustainable forest management practices.
基金supported by the Natural Science Foundation of Guangdong Province,China (No.2025A1515011654)the National Natural Science Foundation of China (No.22090053)+3 种基金the Fundamental Research Funds for National Universities,China University of Geosciences (Wuhan)support from the program of China Scholarships Council (No.202406410155)Young Elite Scientists Sponsorship Program by CAST-Doctoral Student Special Plansupport from the S&T Special Program of Huzhou (No.2024GZ07)。
文摘Field-effect nanofluidic transistors(FENTs),biomimicking the structure and functionality of neuron,act as biological transistors with the ability to gate switching responses to external stimuli.The switching ratio has been verified to evaluate the performance of FENTs,but until recently,the response time,another crucial indicator,has been ignored.Employing finite-element method,we investigated the relationship among gate charge,switching ratio and response time by divisionally manipulating gate charge,including entrance surface and the surface of confinement space,for ion transport to optimize switching capability.The dual-split gate charge on FENTs exhibits synergistic effect on switching response.Based on the two regional gate charge on FENTs,multivalence ions in lower concentration,high aspect ratio and single channel show higher switching ratio but longer response time compared to monovalent ions.The findings highlight the necessity of balancing these two signals in FENTs and offer insights for optimizing their design and expanding applications to dual-signal-detection iontronics.
基金supported by the Fundamental Research Funds for the Central Universities of China(FRF-TP-24-058A)with additional support from the National Key Laboratory of Helicopter Aeromechanics(2024-ZSJ-LB-02-02).
文摘Considering the impact of terminal impact time constraints and the state information of maneuvering targets on the guidance accuracy in multi-UAV cooperative guidance,this paper proposes an impact time cooperative control guidance law(ITCCG)that combines the optimal error dynamics with an improved adaptive cubature Kalman filter(IACKF)algorithm.First,a terminal impact time feedback term is introduced into proportional navigation guidance based on the relative virtual guidance model,and terminal time control is achieved through optimal error dynamics.Then,the Huber loss function is used to reduce the impact of measurement outliers,and the diagonal decomposition is applied to address the issue of non-positive definite matrices that cannot undergo Cholesky decomposition.Finally,the ITCCG and IACKF algorithms combined achieve multi-UAV time-cooperated guidance based on maneuvering target state estimation.Simulation results show that the proposed algorithm effectively reduces the target state estimation error and achieves cooperative guidance within the desired time frame.
基金Supported by National Modern Agricultural Industry Technology System Sichuan Pig Innovation Team(SCCXTD-2026-8)Sichuan Science and Technology Program(2025ZYD0049)"Challenge and Leadership"Project for Key Core Technologies of Sui Ning in Sichuan(2025SNKBZ19).
文摘Sichuan sausages with moisture contents of 40%,45%,50%,and 60% were stored at-18℃for durations of 0,2,4,6,and 8 weeks to evaluate the effect of moisture content on the quality attributes of Sichuan sausages during frozen storage.Product indicators including pH,colour,thiobarbituric acid reactive substances(TBARS),total volatile basic nitrogen(TVB-N),texture,electronic nose(E-nose)response,and water-holding capacity(thawing and cooking losses)were determined.The results indicated that as storage time increased,water retention in Sichuan sausages with different moisture contents decreased,while the degree of protein and lipid oxidation increased.This led to an increase in pH value,a colour shift from red-bright to grey-brown,and a deterioration in palatability.Among the samples,sausages with 50% moisture content exhibited the lowest thawing and cooking losses,indicating superior water-holding capacity.After 8 weeks of storage,TBARS and TVB-N values for the 50% moisture group were 19.5%and 2.5%lower,respectively,than those of the 40%and 45%moisture groups,indicating a reduced degree of oxidation.Furthermore,Sichuan sausage with 50%moisture content demonstrated an appropriate pH and colour difference,along with excellent texture and flavour,as evidenced by its higher toughness and satisfactory hardness.In conclusion,Sichuan sausage with 50% moisture content demonstrated the highest overall quality under frozen storage conditions.
基金supported by the Guangdong Major Project of Basic Research(Grant No.2020B0301030009)the National Natural Science Foundation of China(Grant Nos.12174204,12174203,12074203,62335012,and 62435010)+5 种基金the Natural Science Foundation of Guangdong Province(Grant No.2023A1515012888)the Science and Technology Innovation Commission of Shenzhen(Grant Nos.JCYJ20220818101417039 and JCYJ20241202124428038)the Medical-Engineering Interdisciplinary Research Foundation of Shenzhen University(Grant No.86901/00000311)the Scientific Instrument Developing Project of Shenzhen University(Grant No.2023YQ001)the Shenzhen University 2035 Initiative(Grant No.2023B004)the Key R&D Program of Zhejiang(Grant No.30003AA240100)。
文摘Speckle-based optical cryptosystems are promising technologies for information security.However,existing techniques mostly rely on digital decryption,resulting in computational delay and undermining the high-speed advantage of optical encryption.Moreover,conventional neural networks are typically effective only on images from the same distribution as the training datasets,limiting their general applicability.In this paper,we propose an all-optical high-speed decryption scheme for real-time recovery of speckle-encoded ciphertexts.By constructing a physics-informed diffractive neural network that approximates the inverse transmission matrix of the scattering medium,secret images can be directly reconstructed from speckle fields without optoelectronic conversion or post-processing.The network is trained with only 2048 samples from the MNIST dataset.Its transfer learning capability is validated across three out-of-distribution datasets,with decrypted images achieving a Pearson correlation coefficient of 0.82 and a structural similarity index measure of 0.75,demonstrating excellent transfer learning capability.For the first time,to our knowledge,this scheme simultaneously overcomes the bottlenecks of decryption delay and limited network generalizability in conventional speckle-based cryptosystems,achieving real-time image decryption with strong transferability.It provides a new pathway for developing low-power,real-time,and broadly applicable optical encryption systems,demonstrating significant potential for applications in high-speed security optical communications.
基金Projects(2023 YFC 2907602,2022 YFF 1303302)supported by the National Key Research and Development Project of ChinaProject(52342404)supported by the National Natural Science Foundation of China+2 种基金Project(GXXT-2021-075)supported by the University Synergy Innovation Program of Anhui Province,ChinaProject(2022AH010053)supported by Excellent Scientific Research and Innovation Team of Universities in Anhui Province,ChinaProject(2022xscx080)supported by Anhui Provincial Department of Education Graduate Student Academic Innovation Fund,China。
文摘To study the influence of support timing and support strength on the mechanical properties and deformation damage characteristics of a single-sided unloaded rock mass,a true triaxial perturbation unloaded rock testing system was used to conduct rock damage tests on sandstone with different support timing and strength paths.Based on the acoustic emission monitoring system,the spatial and temporal evolution characteristics of the whole process of rock body loaded instability under two stress paths were studied,and the mechanism of the reinforcing effect of stress support on the unloaded rock mass was analyzed.The results show that,within the scope of this study,both earlier applications of shoring and an increase in shoring strength can effectively improve the ultimate bearing capacity of the unloaded rock,which increases the ultimate bearing capacity of the unloaded rock mass by 60.31% and 54.96%,respectively;There is a phenomenon of rebound deformation of the rock mass during sudden changes in stress(single-sided unloading,stress support),which shows opposite expansion and compression platforms on the stress−strain curve;The crack evolution of unloaded rock under different stress support conditions shows the state law of"initial crack activation→middle steady state expansion→late main crack penetration",and the lagging support significantly accelerates the crack evolution from local activation to main penetration;The single-sided unloading and stress-supporting stages have less influence on the unloading deformationsσ_(1u),σ_(2u) and support deformationsσ_(1) t,σ_(2t) in theσ_(1) andσ_(2)directions,while they show significant response characteristics toσ_(3u),σ_(vu) and σ_(3) t,σ_(vt),and with the increase of the support strength,the stress-supporting stagesσ_(3) t,σ_(vt) gradually increase and exceed the deformations generated by the unloading stagesσ_(3u),σ_(vu);The increase of support strength can effectively compensate for the rock stress loss caused by unloading,which makes the maximum,minimum,and volumetric strain support coefficients during the loading and unloading of the rock body increase gradually while the effect on the intermediate principal strain support coefficient is small;During loading,the support strength of rock masses seeks a new bearing area by regulating stress equilibrium states.This process primarily manifests as a shift in the locations of the crushing zone and the main bearing area,accompanied by a corresponding transformation in failure patterns.Consequently,the rock mass transitions from asymmetric three-zone damage under no or weak support to approximate symmetric three-zone damage under strong support.Simultaneously,the main load-bearing area of the rock mass shifts from deep bearing in the unsupported to middle bearing under strong support as the support strength increases.
