The deformation characteristics and thermal response of anchor rods are crucial for ensuring the stability and safety of surrounding rock support structures.However,existing research has predominantly concentrated on ...The deformation characteristics and thermal response of anchor rods are crucial for ensuring the stability and safety of surrounding rock support structures.However,existing research has predominantly concentrated on the mechanical performance of anchor rods,with limited attention to the coupled evolution of strain and temperature fields during tensile deformation.This knowledge gap hinders a comprehensive understanding of the synergistic mechanical-thermal response mechanisms in anchor rods under loading conditions.To address this limitation,the present study systematically investigated the evolution of strain and temperature fields,along with their correlation,during the test of micro-negative Poisson's ratio(NPR)and ordinary Poisson's ratio(PR)anchor rods.Digital image correlation(DIC)and infrared thermography(IRT)techniques were employed for this exploration.The uniaxial tensile tests were conducted at two different rates,and the ordinary PR anchor rod(Q235 anchor rod)was established as a control group for comparative analysis.The findings reveal that the micro-NPR anchor rod exhibit strain localization at multiple locations during the tensile process,whereas Q235 anchors show local strain concentration in only one region.The standard deviation evolution curves for both the strain and temperature field exhibit two distinct phases in the two anchor rods.The evolution patterns between these two types of curves are basically consistent.The two standard deviation curves for the micro-NPR anchor rod display a wavy increase in the second phase,while for the Q235 anchor rod,they increase steadily until the specimen is damaged.The correlation analysis reveals that the standard deviations of strain and temperature differences for both types of anchor rods are significantly correlated.These findings demonstrate the synergistic evolution mechanism of deformation and thermal response,providing a potential foundation for utilizing thermal monitoring to assess the stability of rock support structures.展开更多
In-situ enlargement of super-large-span tunnels can intensify excavation-induced unloading in the surrounding rock,increasing deformation demand and failure risk during construction.This study combines laboratory mode...In-situ enlargement of super-large-span tunnels can intensify excavation-induced unloading in the surrounding rock,increasing deformation demand and failure risk during construction.This study combines laboratory model tests with FLAC3D simulations to evaluate the stabilizing role of prestressed anchor cables and to establish an energy-balance framework for support optimization.Comparative model tests of existing and enlarged tunnel sections,with and without anchors,show that reinforcement increases load-carrying capacity,reduces displacement,and confines damage to more localized zones.The numerical simulations reproduce displacement fields,shear-strain localization,and plastic-zone evolution with good agreement against the experimental observations.The energy framework is implemented in the in-situ simulations by quantifying unloading-related energy release in the rock mass and reinforcement work contributed by the anchors,and by introducing an energy release–reinforcement ratio as a stability indicator.Parametric analyses indicate that anchor length,spacing,and prestress influence stability in a nonlinear manner,with diminishing returns once reinforcement extends beyond the mechanically dominant deformation zone.An efficient parameter window is identified that improves deformation and yielding control while avoiding unnecessary reinforcement.The results provide an energy-consistent and design-oriented basis for prestressed anchorage selection in large-span tunnel expansion.展开更多
Root-inspired anchorage systems in the field of bio-inspired geotechnics are renowned for enhancing the pullout capacity of traditional geotechnical anchorage systems by simulating the morphology and architecture of p...Root-inspired anchorage systems in the field of bio-inspired geotechnics are renowned for enhancing the pullout capacity of traditional geotechnical anchorage systems by simulating the morphology and architecture of plant root systems.However,limited studies have explored their practical applications,particularly in improving slope stability.To fill this gap,this study investigates the reinforcement effect of root-inspired anchors on slope stabilization using transparent soil modeling and 3D-printed anchors,and examines the impact of anchor branching patterns(i.e.branching numbers,branching angle,and branching nodes)on slope bearing capacity,shear band evolution,and temporal and spatial variation of slope deformation.The results show that peak slope bearing capacity increases with branching numbers and branching angles,correlating with the envelope area of the curved shear band.Upper anchors result in step-like deflections in the shear band near the trailing edge,while lower anchors convert the upward concave shear band into an upward convex one,thus increasing the slope bearing capacity.Slope deformation is minimized with intermediate branching parameters,such as a branching number of 4 and a branching angle of 45°.The anchor reinforcement mechanisms,i.e.anchor rod shear resistance,interface friction,anchor pullout capacity,and plate tightening effects,are comprehensively discussed,and the installation effects resulting from compromise slope modeling are identified as the contributors.These findings shed light on the failure process of root-inspired anchors reinforced slopes and provide a preliminary reference for potential applications,especially for the tradeoff between anchor branching,slope deformation,and slope stability.展开更多
Formamidinium lead iodide(FAPbI_(3))perovskite exhibits an impressive X-ray absorption coefficient and a large carrier mobility-lifetime product(μτ),making it as a highly promising candidate for X-ray detection appl...Formamidinium lead iodide(FAPbI_(3))perovskite exhibits an impressive X-ray absorption coefficient and a large carrier mobility-lifetime product(μτ),making it as a highly promising candidate for X-ray detection application.However,the presence of larger FA^(+)cation induces to an expansion of the Pb-I octahedral framework,which unfortunately affects both the stability and charge carrier mobility of the corresponding devices.To address this challenge,we develop a novel low-dimensional(HtrzT)PbI_(3) perovskite featuring a conjugated organic cation(1H-1,2,4-Triazole-3-thiol,HtrzT^(+))which matches well with theα-FAPbI_(3) lattices in two-dimensional plane.Benefiting from the matched lattice between(HtrzT)PbI_(3) andα-FAPbI_(3),the anchored lattice enhances the Pb-I bond strength and effectively mitigates the inherent tensile strain of theα-FAPbI_(3) crystal lattice.The X-ray detector based on(HtrzT)PbI_(3)(1.0)/FAPbI_(3) device achieves a remarkable sensitivity up to 1.83×10^(5)μC Gy_(air)^(−1) cm^(−2),along with a low detection limit of 27.6 nGy_(air) s^(−1),attributed to the release of residual stress,and the enhancement in carrier mobility-lifetime product.Furthermore,the detector exhibits outstanding stability under X-ray irradiation with tolerating doses equivalent to nearly 1.17×10^(6) chest imaging doses.展开更多
As a primary slope stabilization technique,anchor support encompasses traditional engineering anchors,green anchors,and ecological restoration methods.This review synthesizes two decades of literature to evaluate thes...As a primary slope stabilization technique,anchor support encompasses traditional engineering anchors,green anchors,and ecological restoration methods.This review synthesizes two decades of literature to evaluate these approaches.Current research disproportionately focuses on engineering anchors,while green anchor systems remain less studied despite their dual advantages:reduced labor/economic costs and environmental benefits.Notably,most green anchor studies originate from low-altitude plains,with minimal attention to high-altitude cold-arid regions such as plateaus.We therefore identify slope reinforcement using green anchors in plateau environments as a critical emerging research frontier.展开更多
In geotechnical engineering applications,including mining and tunnel construction,the stability of fractured rock masses is paramount to ensuring structural safety.The spatial distribution and temporal evolution of in...In geotechnical engineering applications,including mining and tunnel construction,the stability of fractured rock masses is paramount to ensuring structural safety.The spatial distribution and temporal evolution of internal fractures fundamentally govern the mechanical behavior and failure mechanisms of rock masses.Nevertheless,the inherent complexity and structural concealment of rock mass systems pose significant challenges for the direct measurement of critical internal mechanical parameters.This study explores the use of deep learning to invert mechanical responses of NPR(Negative Poisson's Ratio)anchored fractured rock masses.Discrete Element Method(DEM)simulations were conducted to generate datasets including stress-strain curves and crack numbers under various initial fracture distributions.Three models—GRU,CNN+GRU,and CNN+GRU+ATT—were developed to predict rock mechanical parameters from NPR cable force data.Results show that the CNN+GRU+ATT model achieves superior accuracy,with R^(2)>0.90 and RMSE<5 on stress prediction tasks.It also accurately estimates initial crack quantity(np),with mean prediction error under 10%for high-fracture scenarios.The proposed model effectively captures stress fluctuations,offering early-warning potential for failure.The approach demonstrates strong generalization and robustness across varying crack configurations,providing a feasible framework for real-time health monitoring and mechanical parameter estimation in fractured rock engineering.展开更多
With the rapid development of deep resource extraction and underground space construction,the design of anchored support systems for jointed rock masses in complex stress environments faces significant challenges.This...With the rapid development of deep resource extraction and underground space construction,the design of anchored support systems for jointed rock masses in complex stress environments faces significant challenges.This study investigates the influence of prefabricated crack dip angles on the mechanical properties of anchored rock masses in deep soft rock roadways.By constructing similarity models of NPR(Negative Poisson’s Ratio)and PR(Positive Poisson’s Ratio)anchored solids,biaxial compression experiments under varying crack dip angles were conducted.Strain gauges,3D Digital Image Correlation(3D DIC),and acoustic emission monitoring were employed to systematically analyze the strength characteristics,deformation-damage evolution,and energy dissipation mechanisms of the two types of anchor systems.The results show that:(1)The stress-strain curves of anchored solids with prefabricated cracks exhibit a distinct bimodal characteristic.Compared to PR anchors,NPR anchors show 20%and 23%improvements in peak strength and elastic modulus,respectively,with residual strength enhanced by up to 34%.(2)Owing to high pre-tightening force and large deformation capacity,NPR anchors maintain superior integrity under increasing crack dip angles,demonstrating more uniform free-surface displacement and localized shear-tensile composite crack patterns.(3)Acoustic emission analysis reveals that NPR anchors exhibit higher cumulative energy absorption(300%improvement over PR anchors)and lack low-rate energy development phases,indicating enhanced ductility and impact resistance at high crack dip angles.(4)Crack dip angle critically governs failure mechanisms by modulating the connectivity between shear cracks and prefabricated fissures:bimodal effects dominate at low angles,while vertical tensile crack propagation replaces bimodal behavior at high angles.The study proposes prioritizing NPR anchor cables in deep engineering applications and optimizing support parameters based on crack dip angles to mitigate stress concentration and ensure the long-term stability of surrounding rock.展开更多
Urinary catheters are essential medical devices widely used for patients requiring urinary drainage,bladder irrigation,or precise urine output monitoring.Transurethral catheters with anchoring balloons are particularl...Urinary catheters are essential medical devices widely used for patients requiring urinary drainage,bladder irrigation,or precise urine output monitoring.Transurethral catheters with anchoring balloons are particularly prevalent among hospitalized patients,facilitating continuous urinary drainage.展开更多
In this paper is presented a concept solution and acceptance test application procedure of deep pit protection structure,intended for three underground levels of residential building:A,B,C,D,block 10C,Budva,Montenegro...In this paper is presented a concept solution and acceptance test application procedure of deep pit protection structure,intended for three underground levels of residential building:A,B,C,D,block 10C,Budva,Montenegro.The anchored wall used consist of nongravity cantilevered walls with three levels of ground anchors.Nongravity cantilevered walls employ continuous walls constructed in slurry trenches(i.e.,slurry(diaphragm)walls),e.g vertical elements that are drilled to depths below the finished excavation grade.For those nongravity cantilevered walls,support is provided through the shear and bending stiffness of the vertical wall elements and passive resistance from the soil below the finished excavation grade.Anchored wall support relies on these components as well as lateral resistance provided by the ground anchors to resist horizontal pressures(e.g.,earth,water,external loads)acting on the wall.Anchored wall analysed and applied is temporary supporting structure necessary for the excavation and erection of the underground structure part up to ground surface level.Temporary ground anchors lifetime is up to two years.Dynamic loads are not considered.展开更多
Experimental and theoretical studies of drag embedment plate anchors recently carried out in Tianjin University are summarized in this research paper, which involve a series of important topics relevant to the study o...Experimental and theoretical studies of drag embedment plate anchors recently carried out in Tianjin University are summarized in this research paper, which involve a series of important topics relevant to the study of drag anchors. The techniques for measuring the trajectory and movement direction of drag anchors in soils, the techniques for measuring the moving embedment point and reverse eatenary shape of the embedded drag line, the penetration mechanism and kinematic behavior of drag anchors, the ultimate embedment depth of drag anchors, the movement direction of the anchor with an arbitrary fluke section, the reverse catenary properties of the embedded drag line, the interaetional properties between drag anchor and installation line, the kinematic model of drag anchors in seabed soils, and the analytical method for predicting the anchor trajectory in soils will all be examined. The present work remarkably reduces the uncertainties in design and analysis of drag embedment plate anchors, and is beneficial to improving the application of this new type of drag anchor in offshore engineering.展开更多
The integration of the digital economy with the traditional sales industry has prompted the robust growth of e-commerce.Live-streaming e-commerce,as a novel business model,has gained immense popularity.However,is⁃sues...The integration of the digital economy with the traditional sales industry has prompted the robust growth of e-commerce.Live-streaming e-commerce,as a novel business model,has gained immense popularity.However,is⁃sues of regulatory loopholes and inefficacy continue to surface.In live-streaming e-commerce,the head anchor,as host of the live-streaming rooms,wields significant influence in determining the goods to be showcased and marketed.Such influence expands risks such as infringement of intellectual property rights.Yet the uncertainty in law concerning the identity of head anchors results in a lack of accountability.Current norms are inadequate in constraining the group of head anchors.Drawing on the principles of risk control,the alignment between benefit and risk,and the theory of so⁃cial cost control,this paper argues that it is both justifiable and feasible to impose a duty to exercise reasonable care on head anchors.To effectively enshrine this duty in law,it is of great importance to redefine the mechanism of identifying the duty of care of head anchors in live-streaming e-commerce.In particular,the contents of the duty of care under⁃taken by head anchors and the consequences of breaching such a duty of care should be clarified.展开更多
Beishan Rock Carvings in Chongqing,a renowned cultural heritage site in China,flourished during the Tang and Song dynasties and are often referred to as the“Stone Carving Art Museum of the Tang and Song Dynasties.”C...Beishan Rock Carvings in Chongqing,a renowned cultural heritage site in China,flourished during the Tang and Song dynasties and are often referred to as the“Stone Carving Art Museum of the Tang and Song Dynasties.”Cave 168 is a key component of the Beishan Rock Carvings.At present,several through-going cracks have developed in the roof of Cave 168,severely compromising the structural stability of the grotto.The early internal steel plate supports have suffered severe corrosion and can no longer provide effective reinforcement.In addition,the presence of steel columns obstructs visitor access and negatively affects the viewing experience.A new reinforcement method is urgently needed.Therefore,studying the deformation patterns of the structure is of critical importance.This study analyzes the stratigraphic parameters and fracture distribution of Cave 168,considering key influencing factors such as rainfall,self-weight,and the overlying Quaternary soil.On-site monitoring and physical model experiments were conducted to evaluate the changes in roof crack width and displacement before and after reinforcement with negative Poisson's ratio(NPR)anchor cables.The results reveal that the roof of Cave 168 contains several through-going cracks and numerous microcracks,which serve as infiltration channels for surface water.These accelerate the softening of the mudstone and pose a significant threat to the cave's structural safety.During the experiment,the main change in the crack exhibited a“semi-archshaped”propagation pattern.In the first ten minutes,as the rock transitioned from dry to moist conditions,a slight crack closure was observed.As rainfall continued,crack propagation accelerated.After rainfall ceased,crack width remained stable over a short period.Under NPR anchor support,the influence of rainfall on roof settlement was effectively mitigated,ensuring the safety and stability of the roof.The NPR anchors successfully limited the roof settlement to within 0.3 mm and provided effective control over both total and differential settlement.These findings offer valuable insights into the application of NPR anchor cables in the conservation of grotto heritage structures.展开更多
Nickel-rich(Ni≥90%)layered oxides materials have emerged as a promising candidate for nextgeneration high-energy-density lithium-ion batteries(LIBs).However,their widespread application is hindered by structural fati...Nickel-rich(Ni≥90%)layered oxides materials have emerged as a promising candidate for nextgeneration high-energy-density lithium-ion batteries(LIBs).However,their widespread application is hindered by structural fatigue and lattice oxygen loss.In this work,an epitaxial surface rock-salt nanolayer is successfully developed on the LiNi_(0.9)Co_(0.1)O_(2)sub-surface via heteroatom anchoring utilizing high-valence element molybdenum modification.This in-situ formed conformal buffer phase with a thickness of 1.2 nm effectively suppresses the continuous interphase side-reactions,and thus maintains the excellent structure integrity at high voltage.Furthermore,theoretical calculations indicate that the lattice oxygen reversibility in the anion framework of the optimized sample is obviously enhanced due to the higher content of O 2p states near the Fermi level than that of the pristine one.Meanwhile,the stronger Mo-O bond further reduces cell volume alteration,which improves the bulk structure stability of modified materials.Besides,the detailed charge compensation mechanism suggests that the average oxidation state of Ni is reduced,which induces more active Li+participating in the redox reactions,boosting the cell energy density.As a result,the uniquely designed cathode materials exhibit an extraordinary discharge capacity of 245.4 mAh g^(-1)at 0.1 C,remarkable rate performance of 169.3 mAh g^(-1)at 10 C at 4.5 V,and a high capacity retention of 70.5% after 1000 cycles in full cells at a high cut-off voltage of 4.4 V.This strategy provides an valuable insight into constructing distinctive heterostructure on highperformance Ni-rich layered cathodes for LIBs.展开更多
The effect of vanadium(V)element on the microstructure and mechanical properties of anchor steel was explored by microstructural characterization and mechanical property tests of anchor steels with different V content...The effect of vanadium(V)element on the microstructure and mechanical properties of anchor steel was explored by microstructural characterization and mechanical property tests of anchor steels with different V contents.The results indicated that the trace addition of V element can generate dispersed VC nanoparticles in the anchor steel and then refine microstructure by inhibiting austenite grain growth.The increase in V content leads to the formation of a larger amount of smaller VC nanoparticles and more refined microstructure.Moreover,the increasing V content in anchor steel causes the volume fraction of ferrite to increase and that of pearlite to decrease continuously,and even leads to the formation of bainite.Accompanied by the microstructure change,the V-treated anchor steels exhibit higher strength compared with the anchor steel without V addition.However,the increased hardness difference between ferrite and pearlite results in poor coordination of deformation between them,leading to a decrease in their plasticity.The impact toughness of anchor steel first increases but then significantly decreases with the increase in V content.The improvement in impact toughness of trace V-treated anchor steel benefits from the enhancement in the band structure after hot rolling,which consumes more energy during the vertical crack propagation process.However,when the V content further increases,the hard and brittle bainite in the anchor steel can facilitate crack initiation and propagation,ultimately resulting in a reduced toughness.展开更多
The development of high-performance metal nanocluster catalysts is hindered by a fundamental stabilization-activity trade-off.Oxide supports often induce over-stabilization via insulating overlayers that block active ...The development of high-performance metal nanocluster catalysts is hindered by a fundamental stabilization-activity trade-off.Oxide supports often induce over-stabilization via insulating overlayers that block active sites,while conventional functionalized carbon supports suffer from thermodynamic instability and weak metal-support electronic coupling,leading to aggregation.Herein,a novel defectmediated covalent anchoring strategy is presented to immobilize transition metal(Pd,Ru,and Ir)NCs within ordered mesoporous carbon.This approach leverages intrinsic micropore defects to capture precursors and facilitate in-situ formation of direct metal-carbon covalent bonds.Controlled pyrolysis confines metal atom sintering into clusters within the mesopores,achieving high metal loading.This enrooted architectu re uniquely balances stability and activity:it avoids the excessive metal-carbon bonding detrimental to single-atom catalysts while maintaining sufficient,controllable interactions.The resulting Pd NCs catalyst exhibits exceptional hydrogen oxidation reaction activity,surpassing mass activity benchmarks of conventional Pt/C.Critically,this methodology decouples atomic-scale stabilization from catalytic site accessibility,resolving the long-standing activity-stability dilemma and providing a generalizable platform for fabricating stable,high-loading cluster catalysts with optimized electronic structures.展开更多
The increasingly serious electromagnetic(EM)radiation and related pollution effects have gradually attracted people's attention in the information age.Hence,it's crucial to develop adaptive shielding materials...The increasingly serious electromagnetic(EM)radiation and related pollution effects have gradually attracted people's attention in the information age.Hence,it's crucial to develop adaptive shielding materials with minimum EM waves(EMW)reflection.In this paper,Ag nanoparticles loaded mesoporous carbon hollow spheres(MCHS@Ag)were synthesized by chemical reduction method,and cellulose nanofibers(CNF)/MXene/MCHS@Ag homogeneous composites were prepared.The total EM interference shielding efficiency(SET)of CNF/MXene/MCHS@Ag composite film was 32.83 dB(at 12.4 GHz),and the absorption effectiveness(SEA)was improved to 26.6 dB,which was 63.1%and 195.5%higher than that of CNF/MXene/MCHS composite film.The low dielectric property of MCHS effectively optimized the impedance matching between the composites and air.The hollow porous structure prolonged the transmission path of EMW and increased the absorption loss of the composites.At the same time,Ag nanoparticles located the MCHS were helpful to construct the internal conductive path overcoming the damage of the conductive property caused by the low dielectric of MCHS.This research adopts a straightforward method to construct a lightweight,pliable,and mesoporous composites for EMI shielding,which serves a crucial role in the current era of severe EM pollution.展开更多
The impacts of natural boulders carried by debris flows pose serious risks to the safety and reliability of structures and buildings.Natural boulders can be highly random and unpredictable.Consequently,boulder control...The impacts of natural boulders carried by debris flows pose serious risks to the safety and reliability of structures and buildings.Natural boulders can be highly random and unpredictable.Consequently,boulder control during debris flows is crucial but difficult.Herein,an eco-friendly control system featuring anchoring natural boulders(NBs)with(negative Poisson's ratio)NPR anchor cables is proposed to form an NB-NPR baffle.A series of flume experiments are conducted to verify the effect of NB-NPR baffles on controlling debris flow impact.The deployment of NB-NPR baffles substantially influences the kinematic behavior of a debris flow,primarily in the form of changes in the depositional properties and impact intensities.The results show that the NB-NPR baffle matrix successfully controls boulder mobility and exhibits positive feedback on solid particle deposition.The NB-NPR baffle group exhibits a reduction in peak impact force ranging from 29%to 79%compared to that of the control group in the basic experiment.The NPR anchor cables play a significant role in the NB-NPR baffle by demonstrating particular characteristics,including consistent resistance,large deformation,and substantial energy absorption.The NB-NPR baffle innovatively utilizes the natural boulders in a debris flow gully by converting destructive boulders into constructive boulders.Overall,this research serves as a basis for future field experiments and applications.展开更多
Weak structural planes commonly exist in underground engineering.These planes make anchor structures more prone to failure,threatening rock stability,threatening the safety and stability of underground engineering.Opt...Weak structural planes commonly exist in underground engineering.These planes make anchor structures more prone to failure,threatening rock stability,threatening the safety and stability of underground engineering.Optical-Thermal-Acoustic(OTA)monitoring was applied during uniaxial compression tests on cross-layer anchored rock masses.The study revealed the mechanical properties,failure characteristics,and energy evolution of rock masses with different anchoring methods and bedding angles.Key findings:anchoring suppresses transverse deformation and tensile crack propagation,increasing elastic modulus and bearing capacity;anchored rock shows more intense acoustic emission but smaller infrared temperature changes;the structural plane angle controls the direction of crack extension and the evolution of the strain characteristics,and the rock is prone to instantaneous slip failure of the structural surface at 45°–75°,and the lower strength with significant IR change characteristics.Distinct OTA characteristics during rupture validate the method's reliability for rockburst early warning and intensity assessment.Moreover,based on the failure characteristics of cross-layer anchored rock masses,a shear failure criterion for anchored structural planes is established.This criterion enables prediction of rock mass failure modes,analysis of bolt support resistance,reference for support design/construction in underground engineering within complex strata.展开更多
基金supported by State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining&Technology,Beijing(Grant No.SKLGDUEK2120)。
文摘The deformation characteristics and thermal response of anchor rods are crucial for ensuring the stability and safety of surrounding rock support structures.However,existing research has predominantly concentrated on the mechanical performance of anchor rods,with limited attention to the coupled evolution of strain and temperature fields during tensile deformation.This knowledge gap hinders a comprehensive understanding of the synergistic mechanical-thermal response mechanisms in anchor rods under loading conditions.To address this limitation,the present study systematically investigated the evolution of strain and temperature fields,along with their correlation,during the test of micro-negative Poisson's ratio(NPR)and ordinary Poisson's ratio(PR)anchor rods.Digital image correlation(DIC)and infrared thermography(IRT)techniques were employed for this exploration.The uniaxial tensile tests were conducted at two different rates,and the ordinary PR anchor rod(Q235 anchor rod)was established as a control group for comparative analysis.The findings reveal that the micro-NPR anchor rod exhibit strain localization at multiple locations during the tensile process,whereas Q235 anchors show local strain concentration in only one region.The standard deviation evolution curves for both the strain and temperature field exhibit two distinct phases in the two anchor rods.The evolution patterns between these two types of curves are basically consistent.The two standard deviation curves for the micro-NPR anchor rod display a wavy increase in the second phase,while for the Q235 anchor rod,they increase steadily until the specimen is damaged.The correlation analysis reveals that the standard deviations of strain and temperature differences for both types of anchor rods are significantly correlated.These findings demonstrate the synergistic evolution mechanism of deformation and thermal response,providing a potential foundation for utilizing thermal monitoring to assess the stability of rock support structures.
基金funded by the National Key R&D Program of China,China(No.2024YFF0507903)the National Key Research and Development Program of China(Grant No.2024YFF0507904)the National Natural Science Foundation of China,China(Grant No.52379114).These supports are gratefully acknowledged.
文摘In-situ enlargement of super-large-span tunnels can intensify excavation-induced unloading in the surrounding rock,increasing deformation demand and failure risk during construction.This study combines laboratory model tests with FLAC3D simulations to evaluate the stabilizing role of prestressed anchor cables and to establish an energy-balance framework for support optimization.Comparative model tests of existing and enlarged tunnel sections,with and without anchors,show that reinforcement increases load-carrying capacity,reduces displacement,and confines damage to more localized zones.The numerical simulations reproduce displacement fields,shear-strain localization,and plastic-zone evolution with good agreement against the experimental observations.The energy framework is implemented in the in-situ simulations by quantifying unloading-related energy release in the rock mass and reinforcement work contributed by the anchors,and by introducing an energy release–reinforcement ratio as a stability indicator.Parametric analyses indicate that anchor length,spacing,and prestress influence stability in a nonlinear manner,with diminishing returns once reinforcement extends beyond the mechanically dominant deformation zone.An efficient parameter window is identified that improves deformation and yielding control while avoiding unnecessary reinforcement.The results provide an energy-consistent and design-oriented basis for prestressed anchorage selection in large-span tunnel expansion.
基金supported by the High-end Foreign Expert Introduction Program(Grant No.G2022165004L)the Sichuan Transportation Science and Technology Project(Grant No.2018-ZL-01)China Railway 20th Bureau Science and Technology Project(Grant No.YF1900SD07B).
文摘Root-inspired anchorage systems in the field of bio-inspired geotechnics are renowned for enhancing the pullout capacity of traditional geotechnical anchorage systems by simulating the morphology and architecture of plant root systems.However,limited studies have explored their practical applications,particularly in improving slope stability.To fill this gap,this study investigates the reinforcement effect of root-inspired anchors on slope stabilization using transparent soil modeling and 3D-printed anchors,and examines the impact of anchor branching patterns(i.e.branching numbers,branching angle,and branching nodes)on slope bearing capacity,shear band evolution,and temporal and spatial variation of slope deformation.The results show that peak slope bearing capacity increases with branching numbers and branching angles,correlating with the envelope area of the curved shear band.Upper anchors result in step-like deflections in the shear band near the trailing edge,while lower anchors convert the upward concave shear band into an upward convex one,thus increasing the slope bearing capacity.Slope deformation is minimized with intermediate branching parameters,such as a branching number of 4 and a branching angle of 45°.The anchor reinforcement mechanisms,i.e.anchor rod shear resistance,interface friction,anchor pullout capacity,and plate tightening effects,are comprehensively discussed,and the installation effects resulting from compromise slope modeling are identified as the contributors.These findings shed light on the failure process of root-inspired anchors reinforced slopes and provide a preliminary reference for potential applications,especially for the tradeoff between anchor branching,slope deformation,and slope stability.
基金supports from the National Natural Science Foundation of China(22375220,U2001214,22471302)the Guangdong Basic and Applied Basic Research Foundation(2024B1515020101)Open Project Fund from State Key Laboratory of Optoelectronic Materials and Technologies(OEMT-2024-KF-08).
文摘Formamidinium lead iodide(FAPbI_(3))perovskite exhibits an impressive X-ray absorption coefficient and a large carrier mobility-lifetime product(μτ),making it as a highly promising candidate for X-ray detection application.However,the presence of larger FA^(+)cation induces to an expansion of the Pb-I octahedral framework,which unfortunately affects both the stability and charge carrier mobility of the corresponding devices.To address this challenge,we develop a novel low-dimensional(HtrzT)PbI_(3) perovskite featuring a conjugated organic cation(1H-1,2,4-Triazole-3-thiol,HtrzT^(+))which matches well with theα-FAPbI_(3) lattices in two-dimensional plane.Benefiting from the matched lattice between(HtrzT)PbI_(3) andα-FAPbI_(3),the anchored lattice enhances the Pb-I bond strength and effectively mitigates the inherent tensile strain of theα-FAPbI_(3) crystal lattice.The X-ray detector based on(HtrzT)PbI_(3)(1.0)/FAPbI_(3) device achieves a remarkable sensitivity up to 1.83×10^(5)μC Gy_(air)^(−1) cm^(−2),along with a low detection limit of 27.6 nGy_(air) s^(−1),attributed to the release of residual stress,and the enhancement in carrier mobility-lifetime product.Furthermore,the detector exhibits outstanding stability under X-ray irradiation with tolerating doses equivalent to nearly 1.17×10^(6) chest imaging doses.
基金supported by a grant from the National Natural Science Foundation of China(42461020)the Gansu Province joint research Fund project(24JRRA799 and 24JRRA857)。
文摘As a primary slope stabilization technique,anchor support encompasses traditional engineering anchors,green anchors,and ecological restoration methods.This review synthesizes two decades of literature to evaluate these approaches.Current research disproportionately focuses on engineering anchors,while green anchor systems remain less studied despite their dual advantages:reduced labor/economic costs and environmental benefits.Notably,most green anchor studies originate from low-altitude plains,with minimal attention to high-altitude cold-arid regions such as plateaus.We therefore identify slope reinforcement using green anchors in plateau environments as a critical emerging research frontier.
基金supported by State Key Laboratory for Tunnel Engineering(TESKL202425)the National Natural Science Foundation of China(Grant Nos.U24A2085,52174096,52304110)+1 种基金the Henan Province Key Research and Development Program(Grant Nos.241111322000)the Henan Provincial Science and Technology Research Project(Grant Nos.252102320020)。
文摘In geotechnical engineering applications,including mining and tunnel construction,the stability of fractured rock masses is paramount to ensuring structural safety.The spatial distribution and temporal evolution of internal fractures fundamentally govern the mechanical behavior and failure mechanisms of rock masses.Nevertheless,the inherent complexity and structural concealment of rock mass systems pose significant challenges for the direct measurement of critical internal mechanical parameters.This study explores the use of deep learning to invert mechanical responses of NPR(Negative Poisson's Ratio)anchored fractured rock masses.Discrete Element Method(DEM)simulations were conducted to generate datasets including stress-strain curves and crack numbers under various initial fracture distributions.Three models—GRU,CNN+GRU,and CNN+GRU+ATT—were developed to predict rock mechanical parameters from NPR cable force data.Results show that the CNN+GRU+ATT model achieves superior accuracy,with R^(2)>0.90 and RMSE<5 on stress prediction tasks.It also accurately estimates initial crack quantity(np),with mean prediction error under 10%for high-fracture scenarios.The proposed model effectively captures stress fluctuations,offering early-warning potential for failure.The approach demonstrates strong generalization and robustness across varying crack configurations,providing a feasible framework for real-time health monitoring and mechanical parameter estimation in fractured rock engineering.
基金supported by the National Natural Science Foundation of China(Grant Nos.52174096 and 52304110).
文摘With the rapid development of deep resource extraction and underground space construction,the design of anchored support systems for jointed rock masses in complex stress environments faces significant challenges.This study investigates the influence of prefabricated crack dip angles on the mechanical properties of anchored rock masses in deep soft rock roadways.By constructing similarity models of NPR(Negative Poisson’s Ratio)and PR(Positive Poisson’s Ratio)anchored solids,biaxial compression experiments under varying crack dip angles were conducted.Strain gauges,3D Digital Image Correlation(3D DIC),and acoustic emission monitoring were employed to systematically analyze the strength characteristics,deformation-damage evolution,and energy dissipation mechanisms of the two types of anchor systems.The results show that:(1)The stress-strain curves of anchored solids with prefabricated cracks exhibit a distinct bimodal characteristic.Compared to PR anchors,NPR anchors show 20%and 23%improvements in peak strength and elastic modulus,respectively,with residual strength enhanced by up to 34%.(2)Owing to high pre-tightening force and large deformation capacity,NPR anchors maintain superior integrity under increasing crack dip angles,demonstrating more uniform free-surface displacement and localized shear-tensile composite crack patterns.(3)Acoustic emission analysis reveals that NPR anchors exhibit higher cumulative energy absorption(300%improvement over PR anchors)and lack low-rate energy development phases,indicating enhanced ductility and impact resistance at high crack dip angles.(4)Crack dip angle critically governs failure mechanisms by modulating the connectivity between shear cracks and prefabricated fissures:bimodal effects dominate at low angles,while vertical tensile crack propagation replaces bimodal behavior at high angles.The study proposes prioritizing NPR anchor cables in deep engineering applications and optimizing support parameters based on crack dip angles to mitigate stress concentration and ensure the long-term stability of surrounding rock.
文摘Urinary catheters are essential medical devices widely used for patients requiring urinary drainage,bladder irrigation,or precise urine output monitoring.Transurethral catheters with anchoring balloons are particularly prevalent among hospitalized patients,facilitating continuous urinary drainage.
文摘In this paper is presented a concept solution and acceptance test application procedure of deep pit protection structure,intended for three underground levels of residential building:A,B,C,D,block 10C,Budva,Montenegro.The anchored wall used consist of nongravity cantilevered walls with three levels of ground anchors.Nongravity cantilevered walls employ continuous walls constructed in slurry trenches(i.e.,slurry(diaphragm)walls),e.g vertical elements that are drilled to depths below the finished excavation grade.For those nongravity cantilevered walls,support is provided through the shear and bending stiffness of the vertical wall elements and passive resistance from the soil below the finished excavation grade.Anchored wall support relies on these components as well as lateral resistance provided by the ground anchors to resist horizontal pressures(e.g.,earth,water,external loads)acting on the wall.Anchored wall analysed and applied is temporary supporting structure necessary for the excavation and erection of the underground structure part up to ground surface level.Temporary ground anchors lifetime is up to two years.Dynamic loads are not considered.
基金Foundation item： Supported by the National Natural Science Foundation of China （Grant nos. 50639030 and 50979070） and the 863 Program of China （Grant no. 2006AA09Z348）.
文摘Experimental and theoretical studies of drag embedment plate anchors recently carried out in Tianjin University are summarized in this research paper, which involve a series of important topics relevant to the study of drag anchors. The techniques for measuring the trajectory and movement direction of drag anchors in soils, the techniques for measuring the moving embedment point and reverse eatenary shape of the embedded drag line, the penetration mechanism and kinematic behavior of drag anchors, the ultimate embedment depth of drag anchors, the movement direction of the anchor with an arbitrary fluke section, the reverse catenary properties of the embedded drag line, the interaetional properties between drag anchor and installation line, the kinematic model of drag anchors in seabed soils, and the analytical method for predicting the anchor trajectory in soils will all be examined. The present work remarkably reduces the uncertainties in design and analysis of drag embedment plate anchors, and is beneficial to improving the application of this new type of drag anchor in offshore engineering.
文摘The integration of the digital economy with the traditional sales industry has prompted the robust growth of e-commerce.Live-streaming e-commerce,as a novel business model,has gained immense popularity.However,is⁃sues of regulatory loopholes and inefficacy continue to surface.In live-streaming e-commerce,the head anchor,as host of the live-streaming rooms,wields significant influence in determining the goods to be showcased and marketed.Such influence expands risks such as infringement of intellectual property rights.Yet the uncertainty in law concerning the identity of head anchors results in a lack of accountability.Current norms are inadequate in constraining the group of head anchors.Drawing on the principles of risk control,the alignment between benefit and risk,and the theory of so⁃cial cost control,this paper argues that it is both justifiable and feasible to impose a duty to exercise reasonable care on head anchors.To effectively enshrine this duty in law,it is of great importance to redefine the mechanism of identifying the duty of care of head anchors in live-streaming e-commerce.In particular,the contents of the duty of care under⁃taken by head anchors and the consequences of breaching such a duty of care should be clarified.
文摘Beishan Rock Carvings in Chongqing,a renowned cultural heritage site in China,flourished during the Tang and Song dynasties and are often referred to as the“Stone Carving Art Museum of the Tang and Song Dynasties.”Cave 168 is a key component of the Beishan Rock Carvings.At present,several through-going cracks have developed in the roof of Cave 168,severely compromising the structural stability of the grotto.The early internal steel plate supports have suffered severe corrosion and can no longer provide effective reinforcement.In addition,the presence of steel columns obstructs visitor access and negatively affects the viewing experience.A new reinforcement method is urgently needed.Therefore,studying the deformation patterns of the structure is of critical importance.This study analyzes the stratigraphic parameters and fracture distribution of Cave 168,considering key influencing factors such as rainfall,self-weight,and the overlying Quaternary soil.On-site monitoring and physical model experiments were conducted to evaluate the changes in roof crack width and displacement before and after reinforcement with negative Poisson's ratio(NPR)anchor cables.The results reveal that the roof of Cave 168 contains several through-going cracks and numerous microcracks,which serve as infiltration channels for surface water.These accelerate the softening of the mudstone and pose a significant threat to the cave's structural safety.During the experiment,the main change in the crack exhibited a“semi-archshaped”propagation pattern.In the first ten minutes,as the rock transitioned from dry to moist conditions,a slight crack closure was observed.As rainfall continued,crack propagation accelerated.After rainfall ceased,crack width remained stable over a short period.Under NPR anchor support,the influence of rainfall on roof settlement was effectively mitigated,ensuring the safety and stability of the roof.The NPR anchors successfully limited the roof settlement to within 0.3 mm and provided effective control over both total and differential settlement.These findings offer valuable insights into the application of NPR anchor cables in the conservation of grotto heritage structures.
基金financially supported by the National Natural Science Foundation of China(No.52202228,52402298)funded by the Science Research Project of Hebei Education Department(No.BJK2022011)+3 种基金the Central Funds Guiding the Local Science and Technology Development of Hebei Province(No.236Z4404G)the Beijing Tianjin Hebei Basic Research Cooperation Special Project(No.E2024202273)the Science and Technology Correspondent Project of Tianjin(24YDTPJC00240)supported by the U.S.Department of Energy’s Office of Science,Office of Basic Energy Science,Materials Sciences and Engineering Division。
文摘Nickel-rich(Ni≥90%)layered oxides materials have emerged as a promising candidate for nextgeneration high-energy-density lithium-ion batteries(LIBs).However,their widespread application is hindered by structural fatigue and lattice oxygen loss.In this work,an epitaxial surface rock-salt nanolayer is successfully developed on the LiNi_(0.9)Co_(0.1)O_(2)sub-surface via heteroatom anchoring utilizing high-valence element molybdenum modification.This in-situ formed conformal buffer phase with a thickness of 1.2 nm effectively suppresses the continuous interphase side-reactions,and thus maintains the excellent structure integrity at high voltage.Furthermore,theoretical calculations indicate that the lattice oxygen reversibility in the anion framework of the optimized sample is obviously enhanced due to the higher content of O 2p states near the Fermi level than that of the pristine one.Meanwhile,the stronger Mo-O bond further reduces cell volume alteration,which improves the bulk structure stability of modified materials.Besides,the detailed charge compensation mechanism suggests that the average oxidation state of Ni is reduced,which induces more active Li+participating in the redox reactions,boosting the cell energy density.As a result,the uniquely designed cathode materials exhibit an extraordinary discharge capacity of 245.4 mAh g^(-1)at 0.1 C,remarkable rate performance of 169.3 mAh g^(-1)at 10 C at 4.5 V,and a high capacity retention of 70.5% after 1000 cycles in full cells at a high cut-off voltage of 4.4 V.This strategy provides an valuable insight into constructing distinctive heterostructure on highperformance Ni-rich layered cathodes for LIBs.
基金supported by the National Natural Science Foundation of China(Nos.52101165,52031013 and 52071322).
文摘The effect of vanadium(V)element on the microstructure and mechanical properties of anchor steel was explored by microstructural characterization and mechanical property tests of anchor steels with different V contents.The results indicated that the trace addition of V element can generate dispersed VC nanoparticles in the anchor steel and then refine microstructure by inhibiting austenite grain growth.The increase in V content leads to the formation of a larger amount of smaller VC nanoparticles and more refined microstructure.Moreover,the increasing V content in anchor steel causes the volume fraction of ferrite to increase and that of pearlite to decrease continuously,and even leads to the formation of bainite.Accompanied by the microstructure change,the V-treated anchor steels exhibit higher strength compared with the anchor steel without V addition.However,the increased hardness difference between ferrite and pearlite results in poor coordination of deformation between them,leading to a decrease in their plasticity.The impact toughness of anchor steel first increases but then significantly decreases with the increase in V content.The improvement in impact toughness of trace V-treated anchor steel benefits from the enhancement in the band structure after hot rolling,which consumes more energy during the vertical crack propagation process.However,when the V content further increases,the hard and brittle bainite in the anchor steel can facilitate crack initiation and propagation,ultimately resulting in a reduced toughness.
基金financially supported by the National Natural Science Foundation of China(No.U2030208&22279082)Sichuan Science and Technology Program(2025YFHZ0056)。
文摘The development of high-performance metal nanocluster catalysts is hindered by a fundamental stabilization-activity trade-off.Oxide supports often induce over-stabilization via insulating overlayers that block active sites,while conventional functionalized carbon supports suffer from thermodynamic instability and weak metal-support electronic coupling,leading to aggregation.Herein,a novel defectmediated covalent anchoring strategy is presented to immobilize transition metal(Pd,Ru,and Ir)NCs within ordered mesoporous carbon.This approach leverages intrinsic micropore defects to capture precursors and facilitate in-situ formation of direct metal-carbon covalent bonds.Controlled pyrolysis confines metal atom sintering into clusters within the mesopores,achieving high metal loading.This enrooted architectu re uniquely balances stability and activity:it avoids the excessive metal-carbon bonding detrimental to single-atom catalysts while maintaining sufficient,controllable interactions.The resulting Pd NCs catalyst exhibits exceptional hydrogen oxidation reaction activity,surpassing mass activity benchmarks of conventional Pt/C.Critically,this methodology decouples atomic-scale stabilization from catalytic site accessibility,resolving the long-standing activity-stability dilemma and providing a generalizable platform for fabricating stable,high-loading cluster catalysts with optimized electronic structures.
基金supported by the National Natural Science Foundation of China(grant no.52273044,52373092)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(grant no.sklpme2023-3-4)+1 种基金the Key Research Program of Zhejiang Province(grant no.2023C01101,2023C01210,2022C01049,2022C01205)the Natural Science Foundation of Zhejiang Province(grant no.LY20E030008).
文摘The increasingly serious electromagnetic(EM)radiation and related pollution effects have gradually attracted people's attention in the information age.Hence,it's crucial to develop adaptive shielding materials with minimum EM waves(EMW)reflection.In this paper,Ag nanoparticles loaded mesoporous carbon hollow spheres(MCHS@Ag)were synthesized by chemical reduction method,and cellulose nanofibers(CNF)/MXene/MCHS@Ag homogeneous composites were prepared.The total EM interference shielding efficiency(SET)of CNF/MXene/MCHS@Ag composite film was 32.83 dB(at 12.4 GHz),and the absorption effectiveness(SEA)was improved to 26.6 dB,which was 63.1%and 195.5%higher than that of CNF/MXene/MCHS composite film.The low dielectric property of MCHS effectively optimized the impedance matching between the composites and air.The hollow porous structure prolonged the transmission path of EMW and increased the absorption loss of the composites.At the same time,Ag nanoparticles located the MCHS were helpful to construct the internal conductive path overcoming the damage of the conductive property caused by the low dielectric of MCHS.This research adopts a straightforward method to construct a lightweight,pliable,and mesoporous composites for EMI shielding,which serves a crucial role in the current era of severe EM pollution.
基金financial support from the National Natural Science Foundation of China(Grant No.41941018).
文摘The impacts of natural boulders carried by debris flows pose serious risks to the safety and reliability of structures and buildings.Natural boulders can be highly random and unpredictable.Consequently,boulder control during debris flows is crucial but difficult.Herein,an eco-friendly control system featuring anchoring natural boulders(NBs)with(negative Poisson's ratio)NPR anchor cables is proposed to form an NB-NPR baffle.A series of flume experiments are conducted to verify the effect of NB-NPR baffles on controlling debris flow impact.The deployment of NB-NPR baffles substantially influences the kinematic behavior of a debris flow,primarily in the form of changes in the depositional properties and impact intensities.The results show that the NB-NPR baffle matrix successfully controls boulder mobility and exhibits positive feedback on solid particle deposition.The NB-NPR baffle group exhibits a reduction in peak impact force ranging from 29%to 79%compared to that of the control group in the basic experiment.The NPR anchor cables play a significant role in the NB-NPR baffle by demonstrating particular characteristics,including consistent resistance,large deformation,and substantial energy absorption.The NB-NPR baffle innovatively utilizes the natural boulders in a debris flow gully by converting destructive boulders into constructive boulders.Overall,this research serves as a basis for future field experiments and applications.
基金supported by the National Natural Science Foundation of China(No.52174081)the National Key Scientific Instruments and Equipment Development Projects of China(No.52227901)。
文摘Weak structural planes commonly exist in underground engineering.These planes make anchor structures more prone to failure,threatening rock stability,threatening the safety and stability of underground engineering.Optical-Thermal-Acoustic(OTA)monitoring was applied during uniaxial compression tests on cross-layer anchored rock masses.The study revealed the mechanical properties,failure characteristics,and energy evolution of rock masses with different anchoring methods and bedding angles.Key findings:anchoring suppresses transverse deformation and tensile crack propagation,increasing elastic modulus and bearing capacity;anchored rock shows more intense acoustic emission but smaller infrared temperature changes;the structural plane angle controls the direction of crack extension and the evolution of the strain characteristics,and the rock is prone to instantaneous slip failure of the structural surface at 45°–75°,and the lower strength with significant IR change characteristics.Distinct OTA characteristics during rupture validate the method's reliability for rockburst early warning and intensity assessment.Moreover,based on the failure characteristics of cross-layer anchored rock masses,a shear failure criterion for anchored structural planes is established.This criterion enables prediction of rock mass failure modes,analysis of bolt support resistance,reference for support design/construction in underground engineering within complex strata.
