Sodium alginate(SA)is generally considered highly hydrophilic due to two hydroxyl groups and a carboxylate group on each pyranose ring.However,SA will form a gel after dissolving in water for a certain period.The two ...Sodium alginate(SA)is generally considered highly hydrophilic due to two hydroxyl groups and a carboxylate group on each pyranose ring.However,SA will form a gel after dissolving in water for a certain period.The two properties of SA,hydrophilicity and gelation,seem to be paradoxical.In this study,to explore the mechanism behind these paradoxical properties,the single-chain behaviors of SA in various liquid environments have been investigated by using single-molecule force spectroscopy(SMFS).In nonpolar solvents such as nonane,SA exhibits its single-chain inherent elasticity consistent with the theoretical elasticity derived from quantum mechanical(QM)calculations.Notably,the experimental curve of SA obtained in water shows a long plateau in the low force region.Further research reveals that this phenomenon is driven by the hydrophobic effect.Additionally,SA shows greater rigidity than its inherent elasticity in the middle and high force regions due to electrostatic repulsion between carboxylate groups on adjacent sugar rings.Comparative single-molecule studies suggest that SA exhibits considerable hydrophobicity,offering new insights into the gelation process in water.展开更多
Raman spectroscopy offers a great power to detect,analyze and identify molecules,and monitor their temporal dynamics and evolution when combined with single-molecule surface-enhanced Raman scattering(SM-SERS)substrate...Raman spectroscopy offers a great power to detect,analyze and identify molecules,and monitor their temporal dynamics and evolution when combined with single-molecule surface-enhanced Raman scattering(SM-SERS)substrates.Here we present a SM-SERS scheme that involves simultaneously giant chemical enhancement from WS22D materials,giant electromagnetic enhancement from plasmonic nanogap hot spot,and inhibition of molecular fluorescence influence under near-infrared laser illumination.Remarkably we find Coulomb attraction between analyte and gold nanoparticle can trigger spontaneous formation of molecule-hotspot pairing with high precision,stability and robustness.The scheme has enabled realization of universal,robust,fast,and large-scale uniform SM-SERS detection for three Raman molecules of rhodamine B,rhodamine 6G,and crystal violet with a very low detection limit of 10−16 M and at a very fast spectrum acquisition time of 50 ms.展开更多
The dynamic regulation of single-molecule magnet(SMM)behavior remains challenging but extremely critical to practical applications.Efficient manipulation of magnetization of complexes via external stimulus,like solven...The dynamic regulation of single-molecule magnet(SMM)behavior remains challenging but extremely critical to practical applications.Efficient manipulation of magnetization of complexes via external stimulus,like solvent,pressure,electric potential or light may further extend the scope of applications for these magnetic molecules.Among these,light is highly desirable because it can provide high-contrast,sensitive and remote control of magnetic behavior at relatively high spatial and temporal resolution.Lanthanide(Ln)complexes represent a distinctive platform for constructing photo-responsive SMMs owing to their extreme sensitivity to subtle change of crystal field(CF)environment.Despite the numerous potential benefits and unique advantages outlined above,light control of magnetism of Ln-SMMs still faces several challenges.This review briefly summarizes recent advancements of photo-responsive Ln-SMMs with photochromic characteristic,highlighting the significance of photoinduced structural changes or electronic distribution alterations to modulate the magnetic properties,which may throw light on the future improvements of photo-responsive molecular materials.展开更多
Transition metal possesses a unique d-orbital electronic structure,which imparts a diverse range of physical and chemical properties.These properties render them significant in fields such as chemistry and materials s...Transition metal possesses a unique d-orbital electronic structure,which imparts a diverse range of physical and chemical properties.These properties render them significant in fields such as chemistry and materials science.The distinctive optical,electrical,and magnetic properties of these complexes can be attributed to the variations in the quantity of d-orbital electrons,thereby influencing their spin and orbital characteristics.The d-orbitals facilitate the formation of stable multidirectional bonds with ligands,resulting in a variety of geometric structures and rich coordination chemistry.These interactions result in variations in energy levels,thereby producing diverse electrical properties,including low attenuation coefficients,high rectification ratios,and unique multichannel transmission.Moreover,the unpaired electrons inthe d-orbitals can give rise to diverse magnetic behaviors,leading to magnetic effects such as spin-related interfaces,switches,and magnetoresistance.This paves the way for extensive possibilities in the design and application of single-molecule devices.This review elaborates on singlemolecule physical properties of transition metal complexes,including length attenuation,rectification,multi-channel transmission,thermoelectric effect,and spin regulation,which are vital for the functionalization and regulation of molecular electronics.In addition,this review also explores the correlation between these physical properties and the electronic structure of transition metals,discussing the broad prospects of transition metal complexes in the fields of nanoelectronics,optoelectronics,and quantum technology.展开更多
The forming processes of 4,40-dipyridyl-based single-molecule junctions and mechanically induced conductance switching as well as the side-group effects are systematically investigated by applying the ab initio-based ...The forming processes of 4,40-dipyridyl-based single-molecule junctions and mechanically induced conductance switching as well as the side-group effects are systematically investigated by applying the ab initio-based adiabatic geometric optimization method and the one-dimensional transmission combined with three-dimensional correction approximation(OTCTCA)method.The numerical results show that for the 4,40-dipyridyl with a p-conjugated phenyl-phosphoryl or diphenylsilyl side group,the pyridyl vertically anchors on the second atomic layer of the pyramid-shaped Au tip electrode at small inter-electrode distances by laterally pushing the apical Au atom aside,which induces stronger pyridyl-electrode coupling and high-conductance state of the formed junctions.As the inter-electrode distance increases,the pyridyl shifts to the apical Au atom of the tip electrode.This apical Au atom introduces additional scatterings to the tunneling electrons and significantly decreases the conductance of the junctions.Furthermore,for the 4,40-dipyridyl with a phenyl-phosphoryl side group,the probability of manifesting the high-conductance state is decreased due to the oxygen atom reducing the probability of the pyridyl adsorbing on the second layer of Au tip electrode.In contrast,for the 4,40-dipyridyl with a nonconjugated cyclohexyl-phosphoryl side group,the steric hindrance from the bulky cyclohexyl group leads the molecule to preferentially form the O-Au contact,which prevents both the high conductance and mechanically induced conductance switching of the junction.Our results provide a theoretical understanding of the side-group effects on electronic transport properties of single-molecule junctions,offering an alternative explanation for the experimental observations.展开更多
Using exact diagonalization of the Hamiltonian and transition matrix in the energy eigenbasis,we perform model calculations of the magnetic relaxation rate in single-molecule magnets.A careful examination of the trans...Using exact diagonalization of the Hamiltonian and transition matrix in the energy eigenbasis,we perform model calculations of the magnetic relaxation rate in single-molecule magnets.A careful examination of the transition matrix reveals that resonant tunneling does not enhance transitions between the nearly degenerate states;rather,it suppresses them.Instead,transitions from one state in the degenerate pair to neighboring states of the other are significantly enhanced.We conduct a detailed analysis of the transition rates to clearly demonstrate how resonant tunneling modulates these processes.This work provides a substantial reinterpretation of the resonant magnetic relaxation in single-molecule magnets and clearly identifies the dominant relaxation pathways.展开更多
The electronic structure of semiconductor materials governs the law of electron motion,which profoundly affects the properties such as conductivity and photoelectric conversion.Photo-responsive single-molecule junctio...The electronic structure of semiconductor materials governs the law of electron motion,which profoundly affects the properties such as conductivity and photoelectric conversion.Photo-responsive single-molecule junction technology provides insights into the electronic structure of photogenerated substances at the molecular scale,enabling the characterization of dynamic processes such as charge separation and energy transfer.These processes involve the unique quantum state known as the "exciton".The electrical characterization technique based on single molecule break junction facilities direct measurement of the photoelectric response of molecules at nanometer and subnanometer scale.This study reviews recent research progress of exciton effects and the characterization of optoelectronic phenomena.The mechanisms of exciton effects in three key optoelectronic phenomena—photoconductivity,photovoltaic s,and photoluminescence—are discussed.Furthermore,advanced spectral characterization techniques applied to the in-situ monitoring of single-molecule optoelectronic devices are highlighted.These include Raman spectroscopy with various enhancements,inelastic electron tunneling spectroscopy,and ultrafast spectroscopy with high resolution.展开更多
Gaining insights into charge transport related to conformational changes and ion transport in valinomycin(VM)is crucial for understanding the underlying physiological processes and advancing ion carrier applications.O...Gaining insights into charge transport related to conformational changes and ion transport in valinomycin(VM)is crucial for understanding the underlying physiological processes and advancing ion carrier applications.Observing these processes in single molecules provides deeper insights and precision than those obtained through conventional ensemble measurements.Herein,we employed a single-molecule conductance measurement method based on the scanning tunneling microscopy break-junction(STM-BJ)to measure the charge transport of individual VM molecules in both non-polar and polar solvents,as well as when mediated by K^(+)ions.Single-molecule conductance measurements revealed that the bracelet and propeller-type conformations of VM in both non-polar and polar solvents significantly affect its conductance.In polar solvents,the propeller-type conformation of VM demonstrated a well-defined conductance signature,single-molecule rectification feature,and through-space transmission mechanism.Specifically,the introduction of K^(+)ions in polar solvents induced a conformational transition from the propeller-type to the bracelet-type form,facilitating K^(+)binding recognition.These observations were further supported by density functional theory combined with non-equilibrium Green’s function calculations.This study enhanced the fundamental understanding of the electronic transport mechanisms in VM and valinomycin-K^(+)molecular junctions,offering insights into VM ionophores and promoting supramolecular sensing applications.展开更多
DNA imaging and visualization techniques are crucial in biological experiments and have also emerged as a powerful method for single-molecule studies.Traditional intercalating dyes(e.g.,SYTOX,EtBr,GelRed)can stain DNA...DNA imaging and visualization techniques are crucial in biological experiments and have also emerged as a powerful method for single-molecule studies.Traditional intercalating dyes(e.g.,SYTOX,EtBr,GelRed)can stain DNA but may alter its structure and mechanical properties,and cause photocleavage.Recently,a novel fluorescent DNA-binding protein(FP-DBP)was introduced,which can stain DNA without sequence preference and without inducing photocleavage.In this study,using a custom-built magnetic tweezers system,we performed DNA stretching,twisting and unzipping experiments to compare the mechanical properties of DNA with and without two kinds of intercalating dyes(SYTOX Orange and GelRed)and mCherry FP-DBP.Our results show that mCherry FP-DBP does not affect DNA structure or mechanics,unlike SYTOX Orange and GelRed,making FP-DBP a promising tool for DNA visualization in single-molecule experiments.展开更多
Clustering is a pivotal data analysis method for deciphering the charge transport properties of single molecules in break junction experiments.However,given the high dimensionality and variability of the data,feature ...Clustering is a pivotal data analysis method for deciphering the charge transport properties of single molecules in break junction experiments.However,given the high dimensionality and variability of the data,feature extraction remains a bottleneck in the development of efficient clustering methods.In this regard,extensive research over the past two decades has focused on feature engineering and dimensionality reduction in break junction conductance.However,extracting highly relevant features without expert knowledge remains an unresolved challenge.To address this issue,we propose a deep clustering method driven by task-oriented representation learning(CTRL)in which the clustering module serves as a guide for the representation learning(RepL)module.First,we determine an optimal autoencoder(AE)structure through a neural architecture search(NAS)to ensure efficient RepL;second,the RepL process is guided by a joint training strategy that combines AE reconstruction loss with the clustering objective.The results demonstrate that CTRL achieves excellent performance on both the generated and experimental data.Further inspection of the RepL step reveals that joint training robustly learns more compact features than the unconstrained AE or traditional dimensionality reduction methods,significantly reducing misclustering possibilities.Our method provides a general end-to-end automatic clustering solution for analyzing single-molecule break junction data.展开更多
Manipulating magnetic couplings in molecular magnets is of great importance in improving the mag-netic properties of such materials.It has been proved that by adjusting the strength of magnetic cou-plings and the arra...Manipulating magnetic couplings in molecular magnets is of great importance in improving the mag-netic properties of such materials.It has been proved that by adjusting the strength of magnetic cou-plings and the arrangement of the intermolecular magnetic dipoles,magnetic blocking can be significantly enhanced.Herein manipulating the intramolecular dipole interactions by ligand modifica-tion was attempted with the use of three closely related dinuclear Er(Ⅲ)complexes of a common chemical formula of[(COT^(R))Er(μ-CI)(THF)]_(2)(COT^(R)is monosubstituted cyclooctatetraenide dianions with R=diphenylmethylsilyl(Ph_(2)MeS)for 1,triethylsilyl(TES)for 2,and triisopropylsilyl(TIPS)for 3).Each of these complexes features a centrosymmetric dinuclear core unit with their component Er(Ⅲ)ions doubly bridged by two chloro ligands and further coordinated with a capping substituted corR ligand and a coordinated THF molecule.Magnetic studies reveal that the complexes display similar ferromagnetic couplings with comparable single-molecule magnetic behaviors.The ferromagnetic couplings dominated by the intramolecular dipole interactions are found to be 0.7614,0.7380,and 0.5635 cm^(-1)for 1,2,and 3,respectively.The angles(θ)between the magnetic easy axes and the intramolecular Er-Er lines are 24.88(2)°,25.23(1),and 31.85(5),leading to transversal dipole fields of 0.0114,0.0113,and 0.0125 T for 1,2,and 3,respectively.Although the different ligand substitution generates a sizable difference of about 7 in theθangle,the resulting difference in the dipole interactions is not sufficiently strong to cause any significant differences in their magnetic properties.Further change in theθangles to the"side-by-side"(θ=90°)or"head-to-tail"(θ=0°)arrangement of the magnetic easy axes,achievable by rational mo-lecular design,is expected to lead to molecular magnetic materials with much enhanced properties.展开更多
The single-molecule detection tech-nique plays a pivotal role in elucidat-ing the fundamental mechanisms of various scientific processes at the molecular level,and holds essential im-portance in multiple fields includ...The single-molecule detection tech-nique plays a pivotal role in elucidat-ing the fundamental mechanisms of various scientific processes at the molecular level,and holds essential im-portance in multiple fields including physics,biology,and chemistry.Re-cently,single-molecule detection has garnered increasing attention owing to its practical utility in medical diagno-sis,primarily due to its exceptional sensitivity and the minimal sample volume required for analysis.However,the conventional single-molecule technique,represented by total internal reflection microscopy,faces challenges such as sophisticated operation procedures and limited detection throughput,thereby impeding its broader application.To address these limitations,we have demonstrated single-molecule detection using an integrated silicon photonic chip,of-fering a cost-effective and user-friendly alternative.By employing basic optics,we efficiently introduce the excitation source for single-molecule fluorescence by harnessing the strong evanescent field of high refractive-index waveguides.Subsequently,fluorescence signals are collected using basic optics comprising a water-immersion objective,relay optics,and a digi-tal camera.Our results highlight a low-cost,high-throughput single-molecule technique achieved through the integrated silicon photonic chip.This innovative approach is promised to facilitate the widespread adoption of single-molecule fluorescence in medical diagnosis.展开更多
Quinoid structures are considered to be conducive to the charge transport of organic molecules,but this hypothesis is rarely proven at single-molecule level.Herein,as a proof of concept,the single-molecule conductance...Quinoid structures are considered to be conducive to the charge transport of organic molecules,but this hypothesis is rarely proven at single-molecule level.Herein,as a proof of concept,the single-molecule conductance of two furan-based isomers,3,3'-bis(4-(methylthio)phenyl)-2,2'-bifuran(2,2'-SMPBF)and 4,4'-bis(4-(methylthio)phenyl)-3,3'-bifuran(3,3'-SMPBF),is investigated by the scanning tunneling microscopy break junction(STM-BJ)technique and theoretical simulation.2,2'-SMPBF prefers to adopt a nearly planar conformation with intact alternating single and double bonds extended via2,2'-bifuran moiety and therefore exhibits goodπ-conjugation and a prominent quinoid structure.However,theπ-conjugation of 3,3'-SMPBF is interrupted due to ineffective cross-conjugation in the 3,3'-bifuran moiety,leading to the absence of a quinoid structure.2,2'-SMPBF displays switchable multiple conductances induced by the interconversion between folded and unfolded conformations and an abnormal rebound of conductance along with the increases of electrode displacement,which is demonstrated to be caused by the quinoid structure in a nearly planar conformation during the stretching process.However,3,3'-SMPBF without a quinoid structure in unfolded conformation exhibits extremely low conductance that cannot be captured in STM-BJ measurements.These results reveal the significant contribution of quinoid structure to molecular charge transport and provide valuable information on the structure-transport relationship for the design of efficient organic semiconductors.展开更多
Due to the ionic feature of the lanthanide ions,to straightly bridge two lanthanide(Ln)ions is rather challenging though this bridging mode is much beneficial to suppress the zero-field quantum tunneling of the magnet...Due to the ionic feature of the lanthanide ions,to straightly bridge two lanthanide(Ln)ions is rather challenging though this bridging mode is much beneficial to suppress the zero-field quantum tunneling of the magnetization(QTM)for single-molecule magnets(SMMs),a kind of nanosized magnetic materials for high-density information storage and magnetic resonance imaging contrast agent.Here we used an unusual terminal amino pyridine ligand which utilizes extensive supramolecular interactions to stabilize such an unusual linear bridging mode and obtained a series of such dimeric Ln(Ⅲ)complexes-{[LnL_(A)(4-NH_(2)py)_(5)]_(2)(μ-Cl)}[BPh_(4)]_(3)(For L_(A)^(-)=1-AdO^(-),1Ln;for L_(A)^(-)=~tBuO^(-),2Ln;Ln=Dy,Gd).More uniquely,the bridging chloride sits in the center of two improper rotation symmetry related Ln(Ⅲ)ions with local C_(5v)symmetry.The dimeric compounds 1Dy and 2Dy exhibit much slower low-temperature magnetic relaxation and thousands of times longer relaxation times at 2 K(τ_(2K)=2706.89 and 1437.05 s for 1Dy and 2Dy)compared to the diluted ones with the approaching magnetic property of the C_(5v)motifs(τ_(2K)=0.77 and 1.29 s for 1Dy@1Y and 2Dy@2Y).Though magnetic interactions mediated via the chloride bridge in both 1Dy and 2Dy are weak and antiferromagnetic,it is still very effective due to such a linear geometry to reduce the QTM effect in SMMs.展开更多
Despite the ongoing increase in the efficiency of perovskite solar cells(PSCs),residual lead iodide(PbI2and moisture sensitivity issues continue to constrain their further commercialization.Herein,we propose a thermal...Despite the ongoing increase in the efficiency of perovskite solar cells(PSCs),residual lead iodide(PbI2and moisture sensitivity issues continue to constrain their further commercialization.Herein,we propose a thermally mediated in situ repair and encapsulation strategy to construct high-performance PSCs by incorporating piperazine thioctic acid salt(TAPPZ)as a dopant into the perovskite precursor Thermally dissociated piperazine(PPZ)from TAPPZ integrates microcrystals to form larger grain(>2000 nm),while the carboxylic acid in thioctic acid(TA)and the amine salt in TAPPZ synergistically passivate and transform PbI_(2),significantly reducing its residual amount.Additionally,TAPPZ undergoe thermal self-crosslinking during perovskite annealing,enabling melt-polymerization to form in situ encapsulation for enhanced water resistance.The TAPPZ-incorporated device achieves a remarkable efficiency of 25.65% and exhibits excellent operational stability,retaining over 90% of its initial efficiency after 2000 h under ambient conditions(20-30℃,20%-30% relative humidity).This study provide new insights into the construction of high-performance perovskite solar cells by designing and synthe sizing multifunctional single molecules for in situ repair and encapsulation of perovskites.展开更多
Protein-protein interactions(PPls)play a crucial role in drug discovery and disease treatment.However,the development of effective drugs targeting PPls remains challenging due to limited methodologies for probing thei...Protein-protein interactions(PPls)play a crucial role in drug discovery and disease treatment.However,the development of effective drugs targeting PPls remains challenging due to limited methodologies for probing their spatiotemporal anisotropy.Here,we propose a single-molecule approach using a unique force circuit to investigate Ppl dynamics and anisotropy under mechanical forces.Unlike conventional techniques,this approach enables the manipulation and real-time monitoring of individual proteins at specific amino acids with defined geometry,offering insights into molecular mechanisms at the single-molecule level.The DNA force circuit was constructed using click chemistry conjugation methods and genetic code expansion techniques,facilitating orthogonal conjugation between proteins and nucleic acids.The SET domain of the MLL1 protein and the tail of histone H3 were used as a model system to demonstrate the application of the DNA force circuit.With the use of atomic force microscopy and magnetic tweezers,optimized assembly procedures were developed.The DNA force circuit provides an exceptional platform for studying the anisotropy of PPis and holds promise for advancing drug discovery research targeted at PPIs.展开更多
A Level考试素有“英国高考”之称。其制度演进大致经历了发轫与探索、扩张与调适、回归与重塑三个阶段,其主要变革内容包括四个方面:组织形式从年终末考的线性考试模式发展为一年多考的模块化考试,再回归线性考试模式;考试评价从常模...A Level考试素有“英国高考”之称。其制度演进大致经历了发轫与探索、扩张与调适、回归与重塑三个阶段,其主要变革内容包括四个方面:组织形式从年终末考的线性考试模式发展为一年多考的模块化考试,再回归线性考试模式;考试评价从常模参照转变为标准参照,评价手段逐步优化;考试要求从注重学科深度转变为强调知识广度,再发展为追求广度和深度并重;考试内容从偏重学术性转变为普职并重,再发展为职普融通和强调基础学科。变革的动因既有来自外部的国际竞争加剧和国内政党轮替,也有来自内部的文化价值观驱动和考试选才效度追求。A Level考试制度对我国高考改革有一定启发,我国可结合国情,以基础学科为支点、职普融通为路径、多样化的考试选择为依托、预测效度为导向,开展本土化探索。展开更多
The root-to-shoot(R/S)ratio is a critical indicator of the balance between root biomass and shoot biomass,representing the ecological strategies and adaptive responses of plants to environmental conditions.However,the...The root-to-shoot(R/S)ratio is a critical indicator of the balance between root biomass and shoot biomass,representing the ecological strategies and adaptive responses of plants to environmental conditions.However,the patterns of change in community R/S ratios during forest succession and their response to moisture levels across broad geographic gradients remains unclear.Based on forest biomass data from a national field inventory of 5,825 plots conducted across China between 2011 and 2015,this study looked into allocating biomass shoots and roots at the early,middle,and late stages of growth in plantations and succession in natural forests,and evaluated how moisture availability influences this allocation.The results revealed a significant decline in R/S ratios from early to late stages for both plantations and natural forests.Shoot and root biomass in plantations grew isometrically during the early and middle succession stages but shifted to allometric growth in the late stage,with the slope of the log-transformed shoot-root biomass relationship differing significantly across growth stages.Natural forests,in contrast,maintained isometric growth across successional stages,showing no significant variation in the slope of the log-transformed shoot-root biomass relationship.Environmental factors,particularly moisture levels,strongly influenced R/S ratios.Moisture levels significantly affected size-corrected R/S ratios,particularly in the middle stage of plantations and the early and middle stages of natural forests,supporting the hypothesis of optimal allocation.These findings suggest that in water-limited regions,forest management should prioritize drought-tolerant,deep-rooted native species,encourage mixed-species planting in the early stage,and reduce logging intensity in mature plantations.Conserving natural forests to maintain successional dynamics is essential for long-term ecological resilience.These findings emphasize the importance of balancing productivity with ecological sustainability by adapting practices to specific environments and forest types under climate change.展开更多
Accurate prediction of rockburst intensity levels is crucial for ensuring the safety of deep hard rock engineering construction.This paper introduced an expert system for rockburst intensity level prediction that empl...Accurate prediction of rockburst intensity levels is crucial for ensuring the safety of deep hard rock engineering construction.This paper introduced an expert system for rockburst intensity level prediction that employs machine learning algorithms as the basis for its inference rules.The system comprises four modules:a database,a repository,an inference engine,and an interpreter.A database containing 1114 rockburst cases was used to construct 357 datasets that serve as the repository for the expert system.Additionally,19 types of machine learning algorithms were used to establish 6783 micro-models to construct cognitive rules within the inference engine.By integrating probability theory and marginal analysis,a fuzzy scoring method based on the SoftMax function was developed and applied to the interpreter for rockburst intensity level prediction,effectively restoring the continuity of rockburst characteristics.The research results indicate that ensemble algorithms based on decision trees are more effective in capturing the characteristics of rockburst.Key factors for accurate prediction of rockburst intensity include uniaxial compressive strength,elastic energy index,the maximum principal stress,tangential stress,and their composite indicators.The accuracy of the proposed rockburst intensity level prediction expert system was verified using 20 engineering rockburst cases,with predictions aligning closely with the actual rockburst intensity levels.展开更多
基金financially supported by the National Natural Science Foundation of China(No.22273079)。
文摘Sodium alginate(SA)is generally considered highly hydrophilic due to two hydroxyl groups and a carboxylate group on each pyranose ring.However,SA will form a gel after dissolving in water for a certain period.The two properties of SA,hydrophilicity and gelation,seem to be paradoxical.In this study,to explore the mechanism behind these paradoxical properties,the single-chain behaviors of SA in various liquid environments have been investigated by using single-molecule force spectroscopy(SMFS).In nonpolar solvents such as nonane,SA exhibits its single-chain inherent elasticity consistent with the theoretical elasticity derived from quantum mechanical(QM)calculations.Notably,the experimental curve of SA obtained in water shows a long plateau in the low force region.Further research reveals that this phenomenon is driven by the hydrophobic effect.Additionally,SA shows greater rigidity than its inherent elasticity in the middle and high force regions due to electrostatic repulsion between carboxylate groups on adjacent sugar rings.Comparative single-molecule studies suggest that SA exhibits considerable hydrophobicity,offering new insights into the gelation process in water.
基金financial support from Science and Technology Project of Guangdong(2020B010190001)National Natural Science Foundation(12434016).
文摘Raman spectroscopy offers a great power to detect,analyze and identify molecules,and monitor their temporal dynamics and evolution when combined with single-molecule surface-enhanced Raman scattering(SM-SERS)substrates.Here we present a SM-SERS scheme that involves simultaneously giant chemical enhancement from WS22D materials,giant electromagnetic enhancement from plasmonic nanogap hot spot,and inhibition of molecular fluorescence influence under near-infrared laser illumination.Remarkably we find Coulomb attraction between analyte and gold nanoparticle can trigger spontaneous formation of molecule-hotspot pairing with high precision,stability and robustness.The scheme has enabled realization of universal,robust,fast,and large-scale uniform SM-SERS detection for three Raman molecules of rhodamine B,rhodamine 6G,and crystal violet with a very low detection limit of 10−16 M and at a very fast spectrum acquisition time of 50 ms.
基金financially supported by the Fundamental Research Program of Shanxi Province(No.202303021222126)the National Natural Science Foundation of China(No.92261103)。
文摘The dynamic regulation of single-molecule magnet(SMM)behavior remains challenging but extremely critical to practical applications.Efficient manipulation of magnetization of complexes via external stimulus,like solvent,pressure,electric potential or light may further extend the scope of applications for these magnetic molecules.Among these,light is highly desirable because it can provide high-contrast,sensitive and remote control of magnetic behavior at relatively high spatial and temporal resolution.Lanthanide(Ln)complexes represent a distinctive platform for constructing photo-responsive SMMs owing to their extreme sensitivity to subtle change of crystal field(CF)environment.Despite the numerous potential benefits and unique advantages outlined above,light control of magnetism of Ln-SMMs still faces several challenges.This review briefly summarizes recent advancements of photo-responsive Ln-SMMs with photochromic characteristic,highlighting the significance of photoinduced structural changes or electronic distribution alterations to modulate the magnetic properties,which may throw light on the future improvements of photo-responsive molecular materials.
基金financially supported by the National Key R&D Program of China(Nos.2021YFA1200102,2021YFA1200101,2023YFF1205803,2022YFE0128700)the National Natural Science Foundation of China(Nos.22173050,22150013,21727806,21933001)+1 种基金Beijing National Laboratory for Molecular Sciences(No.BNLMS-CXXM-202407)the Natural Science Foundation of Beijing(No.2222009)
文摘Transition metal possesses a unique d-orbital electronic structure,which imparts a diverse range of physical and chemical properties.These properties render them significant in fields such as chemistry and materials science.The distinctive optical,electrical,and magnetic properties of these complexes can be attributed to the variations in the quantity of d-orbital electrons,thereby influencing their spin and orbital characteristics.The d-orbitals facilitate the formation of stable multidirectional bonds with ligands,resulting in a variety of geometric structures and rich coordination chemistry.These interactions result in variations in energy levels,thereby producing diverse electrical properties,including low attenuation coefficients,high rectification ratios,and unique multichannel transmission.Moreover,the unpaired electrons inthe d-orbitals can give rise to diverse magnetic behaviors,leading to magnetic effects such as spin-related interfaces,switches,and magnetoresistance.This paves the way for extensive possibilities in the design and application of single-molecule devices.This review elaborates on singlemolecule physical properties of transition metal complexes,including length attenuation,rectification,multi-channel transmission,thermoelectric effect,and spin regulation,which are vital for the functionalization and regulation of molecular electronics.In addition,this review also explores the correlation between these physical properties and the electronic structure of transition metals,discussing the broad prospects of transition metal complexes in the fields of nanoelectronics,optoelectronics,and quantum technology.
基金supported by the National Natural Science Foundation of China(Grant Nos.12474286,22173052,and 12204281).
文摘The forming processes of 4,40-dipyridyl-based single-molecule junctions and mechanically induced conductance switching as well as the side-group effects are systematically investigated by applying the ab initio-based adiabatic geometric optimization method and the one-dimensional transmission combined with three-dimensional correction approximation(OTCTCA)method.The numerical results show that for the 4,40-dipyridyl with a p-conjugated phenyl-phosphoryl or diphenylsilyl side group,the pyridyl vertically anchors on the second atomic layer of the pyramid-shaped Au tip electrode at small inter-electrode distances by laterally pushing the apical Au atom aside,which induces stronger pyridyl-electrode coupling and high-conductance state of the formed junctions.As the inter-electrode distance increases,the pyridyl shifts to the apical Au atom of the tip electrode.This apical Au atom introduces additional scatterings to the tunneling electrons and significantly decreases the conductance of the junctions.Furthermore,for the 4,40-dipyridyl with a phenyl-phosphoryl side group,the probability of manifesting the high-conductance state is decreased due to the oxygen atom reducing the probability of the pyridyl adsorbing on the second layer of Au tip electrode.In contrast,for the 4,40-dipyridyl with a nonconjugated cyclohexyl-phosphoryl side group,the steric hindrance from the bulky cyclohexyl group leads the molecule to preferentially form the O-Au contact,which prevents both the high conductance and mechanically induced conductance switching of the junction.Our results provide a theoretical understanding of the side-group effects on electronic transport properties of single-molecule junctions,offering an alternative explanation for the experimental observations.
基金supported by the National Natural Science Foundation of China(Grant Nos.12404085,12474122,52171188,51771127,and 52111530143)the Fund from DOE-BES(Grant No.DE-FG02-05ER46237)the Central Government Funds of Guiding Local Scientific and Technological Development for Sichuan Province,China(Grant No.2021ZYD0025)。
文摘Using exact diagonalization of the Hamiltonian and transition matrix in the energy eigenbasis,we perform model calculations of the magnetic relaxation rate in single-molecule magnets.A careful examination of the transition matrix reveals that resonant tunneling does not enhance transitions between the nearly degenerate states;rather,it suppresses them.Instead,transitions from one state in the degenerate pair to neighboring states of the other are significantly enhanced.We conduct a detailed analysis of the transition rates to clearly demonstrate how resonant tunneling modulates these processes.This work provides a substantial reinterpretation of the resonant magnetic relaxation in single-molecule magnets and clearly identifies the dominant relaxation pathways.
基金financially supported by the Program of Higher-Level Talents of IMU(No.21300-5223748)the National Natural Science Foundation of China(Nos.22103065 and 21661024)
文摘The electronic structure of semiconductor materials governs the law of electron motion,which profoundly affects the properties such as conductivity and photoelectric conversion.Photo-responsive single-molecule junction technology provides insights into the electronic structure of photogenerated substances at the molecular scale,enabling the characterization of dynamic processes such as charge separation and energy transfer.These processes involve the unique quantum state known as the "exciton".The electrical characterization technique based on single molecule break junction facilities direct measurement of the photoelectric response of molecules at nanometer and subnanometer scale.This study reviews recent research progress of exciton effects and the characterization of optoelectronic phenomena.The mechanisms of exciton effects in three key optoelectronic phenomena—photoconductivity,photovoltaic s,and photoluminescence—are discussed.Furthermore,advanced spectral characterization techniques applied to the in-situ monitoring of single-molecule optoelectronic devices are highlighted.These include Raman spectroscopy with various enhancements,inelastic electron tunneling spectroscopy,and ultrafast spectroscopy with high resolution.
基金supported by the National Key R&D Program of China(Nos.2022YFB3204402,2020YFA0714703 and 2022YFC2205003)the National Natural Science Foundation of China(No.22204135)+2 种基金Hunan Provincial Natural Science Foundation of China(No.2023JJ40619)the Education Department of Hunan Province(No.23A0114)the Science and Technology Innovation Program of Hunan Province(No.2022RC3027)。
文摘Gaining insights into charge transport related to conformational changes and ion transport in valinomycin(VM)is crucial for understanding the underlying physiological processes and advancing ion carrier applications.Observing these processes in single molecules provides deeper insights and precision than those obtained through conventional ensemble measurements.Herein,we employed a single-molecule conductance measurement method based on the scanning tunneling microscopy break-junction(STM-BJ)to measure the charge transport of individual VM molecules in both non-polar and polar solvents,as well as when mediated by K^(+)ions.Single-molecule conductance measurements revealed that the bracelet and propeller-type conformations of VM in both non-polar and polar solvents significantly affect its conductance.In polar solvents,the propeller-type conformation of VM demonstrated a well-defined conductance signature,single-molecule rectification feature,and through-space transmission mechanism.Specifically,the introduction of K^(+)ions in polar solvents induced a conformational transition from the propeller-type to the bracelet-type form,facilitating K^(+)binding recognition.These observations were further supported by density functional theory combined with non-equilibrium Green’s function calculations.This study enhanced the fundamental understanding of the electronic transport mechanisms in VM and valinomycin-K^(+)molecular junctions,offering insights into VM ionophores and promoting supramolecular sensing applications.
基金supported by the National Natural Science Foundation of China(Grant No.32371284)the Open Fund of the State Key Laboratory of Optoelectronic Materials and Technologies,Sun Yatsen University(Grant No.OEMT-2024-ZTS-04)support from the Physical Research Platform in the School of Physics,Sun Yatsen University(Grant No.PRPSP,SYSU).
文摘DNA imaging and visualization techniques are crucial in biological experiments and have also emerged as a powerful method for single-molecule studies.Traditional intercalating dyes(e.g.,SYTOX,EtBr,GelRed)can stain DNA but may alter its structure and mechanical properties,and cause photocleavage.Recently,a novel fluorescent DNA-binding protein(FP-DBP)was introduced,which can stain DNA without sequence preference and without inducing photocleavage.In this study,using a custom-built magnetic tweezers system,we performed DNA stretching,twisting and unzipping experiments to compare the mechanical properties of DNA with and without two kinds of intercalating dyes(SYTOX Orange and GelRed)and mCherry FP-DBP.Our results show that mCherry FP-DBP does not affect DNA structure or mechanics,unlike SYTOX Orange and GelRed,making FP-DBP a promising tool for DNA visualization in single-molecule experiments.
基金supported by Guangxi Science and Technology Program(No.GuiKeAD23026291)Guangxi Science and Technology Major Project(No.AA22068057).
文摘Clustering is a pivotal data analysis method for deciphering the charge transport properties of single molecules in break junction experiments.However,given the high dimensionality and variability of the data,feature extraction remains a bottleneck in the development of efficient clustering methods.In this regard,extensive research over the past two decades has focused on feature engineering and dimensionality reduction in break junction conductance.However,extracting highly relevant features without expert knowledge remains an unresolved challenge.To address this issue,we propose a deep clustering method driven by task-oriented representation learning(CTRL)in which the clustering module serves as a guide for the representation learning(RepL)module.First,we determine an optimal autoencoder(AE)structure through a neural architecture search(NAS)to ensure efficient RepL;second,the RepL process is guided by a joint training strategy that combines AE reconstruction loss with the clustering objective.The results demonstrate that CTRL achieves excellent performance on both the generated and experimental data.Further inspection of the RepL step reveals that joint training robustly learns more compact features than the unconstrained AE or traditional dimensionality reduction methods,significantly reducing misclustering possibilities.Our method provides a general end-to-end automatic clustering solution for analyzing single-molecule break junction data.
基金the National Natural Science Foundation of China(92261203,22101116,21971106)the Science Research Foun dation of jilin Province(YDZJ202301ZYTS478)。
文摘Manipulating magnetic couplings in molecular magnets is of great importance in improving the mag-netic properties of such materials.It has been proved that by adjusting the strength of magnetic cou-plings and the arrangement of the intermolecular magnetic dipoles,magnetic blocking can be significantly enhanced.Herein manipulating the intramolecular dipole interactions by ligand modifica-tion was attempted with the use of three closely related dinuclear Er(Ⅲ)complexes of a common chemical formula of[(COT^(R))Er(μ-CI)(THF)]_(2)(COT^(R)is monosubstituted cyclooctatetraenide dianions with R=diphenylmethylsilyl(Ph_(2)MeS)for 1,triethylsilyl(TES)for 2,and triisopropylsilyl(TIPS)for 3).Each of these complexes features a centrosymmetric dinuclear core unit with their component Er(Ⅲ)ions doubly bridged by two chloro ligands and further coordinated with a capping substituted corR ligand and a coordinated THF molecule.Magnetic studies reveal that the complexes display similar ferromagnetic couplings with comparable single-molecule magnetic behaviors.The ferromagnetic couplings dominated by the intramolecular dipole interactions are found to be 0.7614,0.7380,and 0.5635 cm^(-1)for 1,2,and 3,respectively.The angles(θ)between the magnetic easy axes and the intramolecular Er-Er lines are 24.88(2)°,25.23(1),and 31.85(5),leading to transversal dipole fields of 0.0114,0.0113,and 0.0125 T for 1,2,and 3,respectively.Although the different ligand substitution generates a sizable difference of about 7 in theθangle,the resulting difference in the dipole interactions is not sufficiently strong to cause any significant differences in their magnetic properties.Further change in theθangles to the"side-by-side"(θ=90°)or"head-to-tail"(θ=0°)arrangement of the magnetic easy axes,achievable by rational mo-lecular design,is expected to lead to molecular magnetic materials with much enhanced properties.
基金supported by the National Key Research and Development Program(No.2022YFE0107400)the internal research funding from Photonic View Technology Technology Co.,Ltd.the GuangCi Deep Mind Project of Ruijin Hospital Shanghai Jiao Tong University School of Medicine.
文摘The single-molecule detection tech-nique plays a pivotal role in elucidat-ing the fundamental mechanisms of various scientific processes at the molecular level,and holds essential im-portance in multiple fields including physics,biology,and chemistry.Re-cently,single-molecule detection has garnered increasing attention owing to its practical utility in medical diagno-sis,primarily due to its exceptional sensitivity and the minimal sample volume required for analysis.However,the conventional single-molecule technique,represented by total internal reflection microscopy,faces challenges such as sophisticated operation procedures and limited detection throughput,thereby impeding its broader application.To address these limitations,we have demonstrated single-molecule detection using an integrated silicon photonic chip,of-fering a cost-effective and user-friendly alternative.By employing basic optics,we efficiently introduce the excitation source for single-molecule fluorescence by harnessing the strong evanescent field of high refractive-index waveguides.Subsequently,fluorescence signals are collected using basic optics comprising a water-immersion objective,relay optics,and a digi-tal camera.Our results highlight a low-cost,high-throughput single-molecule technique achieved through the integrated silicon photonic chip.This innovative approach is promised to facilitate the widespread adoption of single-molecule fluorescence in medical diagnosis.
基金financially supported by the National Natural Science Foundation of China(Nos.U23A20594,22375066 and 21788102)Guang Dong Basic and Applied Basic Research Foundation(No.2023B1515040003)。
文摘Quinoid structures are considered to be conducive to the charge transport of organic molecules,but this hypothesis is rarely proven at single-molecule level.Herein,as a proof of concept,the single-molecule conductance of two furan-based isomers,3,3'-bis(4-(methylthio)phenyl)-2,2'-bifuran(2,2'-SMPBF)and 4,4'-bis(4-(methylthio)phenyl)-3,3'-bifuran(3,3'-SMPBF),is investigated by the scanning tunneling microscopy break junction(STM-BJ)technique and theoretical simulation.2,2'-SMPBF prefers to adopt a nearly planar conformation with intact alternating single and double bonds extended via2,2'-bifuran moiety and therefore exhibits goodπ-conjugation and a prominent quinoid structure.However,theπ-conjugation of 3,3'-SMPBF is interrupted due to ineffective cross-conjugation in the 3,3'-bifuran moiety,leading to the absence of a quinoid structure.2,2'-SMPBF displays switchable multiple conductances induced by the interconversion between folded and unfolded conformations and an abnormal rebound of conductance along with the increases of electrode displacement,which is demonstrated to be caused by the quinoid structure in a nearly planar conformation during the stretching process.However,3,3'-SMPBF without a quinoid structure in unfolded conformation exhibits extremely low conductance that cannot be captured in STM-BJ measurements.These results reveal the significant contribution of quinoid structure to molecular charge transport and provide valuable information on the structure-transport relationship for the design of efficient organic semiconductors.
基金supported by the National Natural Science Foundation of China(No.22375157)the State Key Laboratory of Electrical Insulation and Power Equipment(No.EIPE23405)+2 种基金the Fundamental Research Funds for Central Universities(No.xtr052023002)the Special Support Plan of Shaanxi Province for Young Top-notch Talentthe Medical-Engineering Cross Project of the First Affiliated Hospital of XJTU(No.QYJC02)。
文摘Due to the ionic feature of the lanthanide ions,to straightly bridge two lanthanide(Ln)ions is rather challenging though this bridging mode is much beneficial to suppress the zero-field quantum tunneling of the magnetization(QTM)for single-molecule magnets(SMMs),a kind of nanosized magnetic materials for high-density information storage and magnetic resonance imaging contrast agent.Here we used an unusual terminal amino pyridine ligand which utilizes extensive supramolecular interactions to stabilize such an unusual linear bridging mode and obtained a series of such dimeric Ln(Ⅲ)complexes-{[LnL_(A)(4-NH_(2)py)_(5)]_(2)(μ-Cl)}[BPh_(4)]_(3)(For L_(A)^(-)=1-AdO^(-),1Ln;for L_(A)^(-)=~tBuO^(-),2Ln;Ln=Dy,Gd).More uniquely,the bridging chloride sits in the center of two improper rotation symmetry related Ln(Ⅲ)ions with local C_(5v)symmetry.The dimeric compounds 1Dy and 2Dy exhibit much slower low-temperature magnetic relaxation and thousands of times longer relaxation times at 2 K(τ_(2K)=2706.89 and 1437.05 s for 1Dy and 2Dy)compared to the diluted ones with the approaching magnetic property of the C_(5v)motifs(τ_(2K)=0.77 and 1.29 s for 1Dy@1Y and 2Dy@2Y).Though magnetic interactions mediated via the chloride bridge in both 1Dy and 2Dy are weak and antiferromagnetic,it is still very effective due to such a linear geometry to reduce the QTM effect in SMMs.
基金supported by the National Natural Science Foundation of China(22238002 and 22208047)the China Postdoctoral Science Foundation(2024T170086 and 2022M720639)+1 种基金the Research and Innovation Team Project of Dalian University of Technology(DUT2022TB10)the Fundamental Research Funds for the Central Universities(DUT22LAB610)。
文摘Despite the ongoing increase in the efficiency of perovskite solar cells(PSCs),residual lead iodide(PbI2and moisture sensitivity issues continue to constrain their further commercialization.Herein,we propose a thermally mediated in situ repair and encapsulation strategy to construct high-performance PSCs by incorporating piperazine thioctic acid salt(TAPPZ)as a dopant into the perovskite precursor Thermally dissociated piperazine(PPZ)from TAPPZ integrates microcrystals to form larger grain(>2000 nm),while the carboxylic acid in thioctic acid(TA)and the amine salt in TAPPZ synergistically passivate and transform PbI_(2),significantly reducing its residual amount.Additionally,TAPPZ undergoe thermal self-crosslinking during perovskite annealing,enabling melt-polymerization to form in situ encapsulation for enhanced water resistance.The TAPPZ-incorporated device achieves a remarkable efficiency of 25.65% and exhibits excellent operational stability,retaining over 90% of its initial efficiency after 2000 h under ambient conditions(20-30℃,20%-30% relative humidity).This study provide new insights into the construction of high-performance perovskite solar cells by designing and synthe sizing multifunctional single molecules for in situ repair and encapsulation of perovskites.
基金This work was supported by the National Natural Science Foundation of China[Grant 32071227 to Z.Y.,Grant 12275137 to Y.L.]Tianjin Municipal Natural Science Foundation of China(22JCYBJC01070 to Z.Y.)State Key Laboratory of Precision Measuring Technology and Instruments(Tianjin University)[Grant pilab2210 to Z.Y.].
文摘Protein-protein interactions(PPls)play a crucial role in drug discovery and disease treatment.However,the development of effective drugs targeting PPls remains challenging due to limited methodologies for probing their spatiotemporal anisotropy.Here,we propose a single-molecule approach using a unique force circuit to investigate Ppl dynamics and anisotropy under mechanical forces.Unlike conventional techniques,this approach enables the manipulation and real-time monitoring of individual proteins at specific amino acids with defined geometry,offering insights into molecular mechanisms at the single-molecule level.The DNA force circuit was constructed using click chemistry conjugation methods and genetic code expansion techniques,facilitating orthogonal conjugation between proteins and nucleic acids.The SET domain of the MLL1 protein and the tail of histone H3 were used as a model system to demonstrate the application of the DNA force circuit.With the use of atomic force microscopy and magnetic tweezers,optimized assembly procedures were developed.The DNA force circuit provides an exceptional platform for studying the anisotropy of PPis and holds promise for advancing drug discovery research targeted at PPIs.
基金supported by the China National Science Foundation(No.42130506,42071031)the Special Technology Innovation Fund of Carbon Peak and Carbon Neutrality in Jiangsu Province(BK20231515)+1 种基金the Spanish Government grant PID2022-140808NB-I00 funded by MICIU/AEI/https://doi.org/10.13039/501100011033the Catalan Government grants SGR 2021-1333 and AGAUR2023 CLIMA 00118.
文摘The root-to-shoot(R/S)ratio is a critical indicator of the balance between root biomass and shoot biomass,representing the ecological strategies and adaptive responses of plants to environmental conditions.However,the patterns of change in community R/S ratios during forest succession and their response to moisture levels across broad geographic gradients remains unclear.Based on forest biomass data from a national field inventory of 5,825 plots conducted across China between 2011 and 2015,this study looked into allocating biomass shoots and roots at the early,middle,and late stages of growth in plantations and succession in natural forests,and evaluated how moisture availability influences this allocation.The results revealed a significant decline in R/S ratios from early to late stages for both plantations and natural forests.Shoot and root biomass in plantations grew isometrically during the early and middle succession stages but shifted to allometric growth in the late stage,with the slope of the log-transformed shoot-root biomass relationship differing significantly across growth stages.Natural forests,in contrast,maintained isometric growth across successional stages,showing no significant variation in the slope of the log-transformed shoot-root biomass relationship.Environmental factors,particularly moisture levels,strongly influenced R/S ratios.Moisture levels significantly affected size-corrected R/S ratios,particularly in the middle stage of plantations and the early and middle stages of natural forests,supporting the hypothesis of optimal allocation.These findings suggest that in water-limited regions,forest management should prioritize drought-tolerant,deep-rooted native species,encourage mixed-species planting in the early stage,and reduce logging intensity in mature plantations.Conserving natural forests to maintain successional dynamics is essential for long-term ecological resilience.These findings emphasize the importance of balancing productivity with ecological sustainability by adapting practices to specific environments and forest types under climate change.
基金Project(42077244)supported by the National Natural Science Foundation of ChinaProject(2020-05)supported by the Open Research Fund of Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization,China。
文摘Accurate prediction of rockburst intensity levels is crucial for ensuring the safety of deep hard rock engineering construction.This paper introduced an expert system for rockburst intensity level prediction that employs machine learning algorithms as the basis for its inference rules.The system comprises four modules:a database,a repository,an inference engine,and an interpreter.A database containing 1114 rockburst cases was used to construct 357 datasets that serve as the repository for the expert system.Additionally,19 types of machine learning algorithms were used to establish 6783 micro-models to construct cognitive rules within the inference engine.By integrating probability theory and marginal analysis,a fuzzy scoring method based on the SoftMax function was developed and applied to the interpreter for rockburst intensity level prediction,effectively restoring the continuity of rockburst characteristics.The research results indicate that ensemble algorithms based on decision trees are more effective in capturing the characteristics of rockburst.Key factors for accurate prediction of rockburst intensity include uniaxial compressive strength,elastic energy index,the maximum principal stress,tangential stress,and their composite indicators.The accuracy of the proposed rockburst intensity level prediction expert system was verified using 20 engineering rockburst cases,with predictions aligning closely with the actual rockburst intensity levels.
