Software security poses substantial risks to our society because software has become part of our life. Numerous techniques have been proposed to resolve or mitigate the impact of software security issues. Among them, ...Software security poses substantial risks to our society because software has become part of our life. Numerous techniques have been proposed to resolve or mitigate the impact of software security issues. Among them, software testing and analysis are two of the critical methods, which significantly benefit from the advancements in deep learning technologies. Due to the successful use of deep learning in software security, recently,researchers have explored the potential of using large language models(LLMs) in this area. In this paper, we systematically review the results focusing on LLMs in software security. We analyze the topics of fuzzing, unit test, program repair, bug reproduction, data-driven bug detection, and bug triage. We deconstruct these techniques into several stages and analyze how LLMs can be used in the stages. We also discuss the future directions of using LLMs in software security, including the future directions for the existing use of LLMs and extensions from conventional deep learning research.展开更多
ChatGPT is a powerful artificial intelligence(AI)language model that has demonstrated significant improvements in various natural language processing(NLP) tasks. However, like any technology, it presents potential sec...ChatGPT is a powerful artificial intelligence(AI)language model that has demonstrated significant improvements in various natural language processing(NLP) tasks. However, like any technology, it presents potential security risks that need to be carefully evaluated and addressed. In this survey, we provide an overview of the current state of research on security of using ChatGPT, with aspects of bias, disinformation, ethics, misuse,attacks and privacy. We review and discuss the literature on these topics and highlight open research questions and future directions.Through this survey, we aim to contribute to the academic discourse on AI security, enriching the understanding of potential risks and mitigations. We anticipate that this survey will be valuable for various stakeholders involved in AI development and usage, including AI researchers, developers, policy makers, and end-users.展开更多
Lithium niobate(LN)has remained at the forefront of academic research and industrial applications due to its rich material properties,which include second-order nonlinear optic,electro-optic,and piezoelectric properti...Lithium niobate(LN)has remained at the forefront of academic research and industrial applications due to its rich material properties,which include second-order nonlinear optic,electro-optic,and piezoelectric properties.A further aspect of LN’s versatility stems from the ability to engineer ferroelectric domains with micro and even nano-scale precision in LN,which provides an additional degree of freedom to design acoustic and optical devices with improved performance and is only possible in a handful of other materials.In this review paper,we provide an overview of the domain engineering techniques developed for LN,their principles,and the typical domain size and pattern uniformity they provide,which is important for devices that require high-resolution domain patterns with good reproducibility.It also highlights each technique's benefits,limitations,and adaptability for an application,along with possible improvements and future advancement prospects.Further,the review provides a brief overview of domain visualization methods,which is crucial to gain insights into domain quality/shape and explores the adaptability of the proposed domain engineering methodologies for the emerging thin-film lithium niobate on an insulator platform,which creates opportunities for developing the next generation of compact and scalable photonic integrated circuits and high frequency acoustic devices.展开更多
Catalytic oxidation of organic pollutants is a well-known and effective technique for pollutant abatement.Unfortunately,this method is significantly hindered in practical applications by the lowefficiency and difficul...Catalytic oxidation of organic pollutants is a well-known and effective technique for pollutant abatement.Unfortunately,this method is significantly hindered in practical applications by the lowefficiency and difficult recovery of the catalysts in a powdery form.Herein,a three-dimensional(3D)framework of Fe-incorporated Ni_(3)S_(2)nanosheets in-situ grown on Ni foam(Fe-Ni_(3)S_(2)@NF)was fabricated by a facile two-step hydrothermal process and applied to trigger peroxymonosulfate(PMS)oxidation of organic compounds inwater.A homogeneous growth environment enabled the uniform and scalable growth of Fe-Ni_(3)S_(2)nanosheets on the Ni foam.Fe-Ni_(3)S_(2)@NF possessed outstanding activity and durability in activating PMS,as it effectively facilitated electron transfer from organic pollutants to PMS.Fe-Ni_(3)S_(2)@NF initially supplied electrons to PMS,causing the catalyst to undergo oxidation,and subsequently accepted electrons from organic compounds,returning to its initial state.The introduction of Fe into the Ni_(3)S_(2)lattice enhanced electrical conductivity,promoting mediated electron transfer between PMS and organic compounds.The 3D conductive Ni foam provided an ideal platform for the nucleation and growth of Fe-Ni_(3)S_(2),accelerating pollutant abatement due to its porous structure and high conductivity.Furthermore,its monolithic nature simplified the catalyst recycling process.A continuous flow packed-bed reactor by encapsulating Fe-Ni_(3)S_(2)@NF catalyst achieved complete pollutant abatement with continuous operation for 240 h,highlighting its immense potential for practical environmental remediation.This study presents a facile synthesis method for creating a novel type of monolithic catalyst with high activity and durability for decontamination through Fenton-like processes.展开更多
This paper addresses the consensus problem of nonlinear multi-agent systems subject to external disturbances and uncertainties under denial-ofservice(DoS)attacks.Firstly,an observer-based state feedback control method...This paper addresses the consensus problem of nonlinear multi-agent systems subject to external disturbances and uncertainties under denial-ofservice(DoS)attacks.Firstly,an observer-based state feedback control method is employed to achieve secure control by estimating the system's state in real time.Secondly,by combining a memory-based adaptive eventtriggered mechanism with neural networks,the paper aims to approximate the nonlinear terms in the networked system and efficiently conserve system resources.Finally,based on a two-degree-of-freedom model of a vehicle affected by crosswinds,this paper constructs a multi-unmanned ground vehicle(Multi-UGV)system to validate the effectiveness of the proposed method.Simulation results show that the proposed control strategy can effectively handle external disturbances such as crosswinds in practical applications,ensuring the stability and reliable operation of the Multi-UGV system.展开更多
Understanding the dynamic responses of hard rocks is crucial during deep mining and tunneling activities and when constructing nuclear waste repositories. However, the response of deep massive rocks with openings of d...Understanding the dynamic responses of hard rocks is crucial during deep mining and tunneling activities and when constructing nuclear waste repositories. However, the response of deep massive rocks with openings of different shapes and orientations to dynamic loading is not well understood. Therefore, this study investigates the dynamic responses of hard rocks of deep underground excavation activities. Split Hopkins Pressure Bar (SHPB) tests on granite with holes of different shapes (rectangle, circle, vertical ellipse (elliptical short (ES) axis parallel to the impact load direction), and horizontal ellipse (elliptical long (EL) axis parallel to the impact load direction)) were carried out. The influence of hole shape and location on the dynamic responses was analyzed to reveal the rocks' dynamic strengths and cracking characteristics. We used the ResNet18 (convolutional neural network-based) network to recognize crack types using high-speed photographs. Moreover, a prediction model for the stress-strain response of rocks with different openings was established using Deep Neural Network (DNN). The results show that the dynamic strengths of the granite with EL and ES holes are the highest and lowest, respectively. The strength-weakening coefficient decreases first and then increases with an increase of thickness-span ratio (h/L). The weakening of the granite with ES holes is the most obvious. The ResNet18 network can improve the analyzing efficiency of the cracking mechanism, and the trained model's recognition accuracy reaches 99%. Finally, the dynamic stress-strain prediction model can predict the complete stress-strain curve well, with an accuracy above 85%.展开更多
Layer-structured Ruddlesden–Popper(RP)perovskites(RPPs)with decent stability have captured the imagination of the photovoltaic research community and bring hope for boosting the development of perovskite solar cell(P...Layer-structured Ruddlesden–Popper(RP)perovskites(RPPs)with decent stability have captured the imagination of the photovoltaic research community and bring hope for boosting the development of perovskite solar cell(PSC)technology.However,two-dimensional(2D)or quasi-2D RP PSCs are encountered with some challenges of the large exciton binding energy,blocked charge transport and poor film quality,which restrict their photovoltaic performance.Fortunately,these issues can be readily resolved by rationally designing spacer cations of RPPs.This review mainly focuses on how to design the molecular structures of organic spacers and aims to endow RPPs with outstanding photovoltaic applications.We firstly elucidated the important roles of organic spacers in impacting crystallization kinetics,charge transporting ability and stability of RPPs.Then we brought three aspects to attention for designing organic spacers.Finally,we presented the specific molecular structure design strategies for organic spacers of RPPs aiming to improve photovoltaic performance of RP PSCs.These proposed strategies in this review will provide new avenues to develop novel organic spacers for RPPs and advance the development of RPP photovoltaic technology for future applications.展开更多
The Ediacaran-Cambrian Petermann Orogen is a dextral transpressional orogen exposed in central Australia,which facilitated the exhumation of a high-pressure core and the deformation of the Neoproterozoic-Palaeozoic Am...The Ediacaran-Cambrian Petermann Orogen is a dextral transpressional orogen exposed in central Australia,which facilitated the exhumation of a high-pressure core and the deformation of the Neoproterozoic-Palaeozoic Amadeus Basin.Several studies have investigated the metamorphic and deformational evolution of the Petermann Orogen;however,the spatiotemporal variation of the deformation and cooling history is yet to be fully understood.In situ muscovite and biotite Rb-Sr geochronology,in combination with Ti-in-quartz thermometry is applied to map the spatiotemporal deformation and cooling patterns of the northern part of the Petermann Orogen.Interpreted muscovite Rb-Sr growth ages obtained from samples in the Petermann Nappe Complex(PNC),range between c.598 Ma and 565 Ma,which correlate with the timing of deformation during the 600-520 Ma Petermann Orogeny.Interpreted muscovite and biotite cooling ages are younger in the east of the PNC(c.556-541 Ma)and broadly correlate with the regional pattern of crustal heat production,suggesting that the geothermal gradient had a significant control on the timing and duration of cooling.Biotite Rb-Sr cooling ages between c.555 Ma and 497 Ma for the orogenic core show no correlation with high heat production areas,however,differences in exhumed crustal levels across the Petermann Orogen are observed:high-P granulite facies rocks in the orogenic core vs middle-upper crustal rocks in the PNC,indicating that at least part of the spatiotemporal variation of cooling ages can be attributed to differential exhumation during the Petermann Orogeny.Hence,crustal heat production and differential exhumation were likely the main controlling factors on the duration and variation of cooling rates in the Petermann Orogen.展开更多
The stability of underground tunnel roofs is strongly influenced by wedge blocks formed by complex joint networks.The mechanical behavior and failure mechanisms of different roof wedge blocks in arched holes were inve...The stability of underground tunnel roofs is strongly influenced by wedge blocks formed by complex joint networks.The mechanical behavior and failure mechanisms of different roof wedge blocks in arched holes were investigated under biaxial stress conditions.The crack evolution and failure modes of the specimens were analyzed through acoustic emission(AE),digital image correlation(DIC),and discrete element method(DEM).Results show significant variations in mechanical properties:specimens T1(extremely unstable triangular)and T2(extremely unstable quadrilateral)exhibited higher strength than T3(extremely stable triangular)and T4(extremely stable quadrilateral),while support more effectively enhanced the strength of T3 and T4.Failure modes were classified as rock-dominated,wedgedominated,or co-dominated.Cracks typically initiated near the wedge and propagated outward.Unsupported specimens developed tensile cracks at the hole bottom,shear cracks at the sides,and mixed cracks along wedge boundaries,whereas supported specimens mainly exhibited cracks at the roof and sides.Stress analysis indicated that unsupported conditions induced high stress differences,promoting localized shear failure.Wedge geometry significantly affected shear stress redistribution at the roof.These findings highlight the critical role of support and wedge block geometry in controlling stress dis-tribution and failure mechanisms in arched tunnels.展开更多
Advanced oxidation processes(AOPs)governed by peroxide activation to produce highly oxidative active species have been extensively explored for environmental remediation.Nevertheless,the low diffusion rates,inadequate...Advanced oxidation processes(AOPs)governed by peroxide activation to produce highly oxidative active species have been extensively explored for environmental remediation.Nevertheless,the low diffusion rates,inadequate interactions of the reactants,and limited active site exposure hinder treatment efficiency.Porous carbocatalysts with high specific surface area,tunable pore size,and programmable active sites demonstrate outstanding performance in activating diverse types of peroxides to generate active species for treatment of aqueous organic pollutants.The pore-rich structures enhance reaction kinetics for peroxide activation by facilitating diffusion of the reactants and their interactions.Additionally,the structural flexibility of porous structures favors the accommodation of highly dispersed metal species and allows for precise tuning of the microenvironment around the active sites,which further enhances the catalytic activity.This review critically summarizes the recent research progress in the applications of engineered porous carbocatalysts for peroxide activation and outlines the prevailing pore construction methods in carbocatalysts.Moreover,engineering strategies to regulate the mass transfer efficiency and fine-tune the microenvironment around the active sites are systematically addressed to enhance their catalytic peroxide activation performances.Challenges and future research opportunities pertaining to the design,optimization,mechanistic investigation,and practical application of porous carbocatalysts in peroxide activation are also proposed.展开更多
Long-term niche differentiation will lead to the evolution of diverse adaptive strategies for species in diverse environments. The present study selected two Forsythia species, Forsythia mandshurica(Fm)-which naturall...Long-term niche differentiation will lead to the evolution of diverse adaptive strategies for species in diverse environments. The present study selected two Forsythia species, Forsythia mandshurica(Fm)-which naturally occurs in a cold temperate zone and Forsythia suspensa(Fs)-which thrives in a warm temperate zone-to reveal their differential chilling defense mechanisms by integrating morpho-physiological,transcriptomic, and metabolomic data. Transcriptome results show that Fm has evolved in a series of adaptive mechanisms designed to help the plants to cope with chilling stress by enhancing sugar, amino acid, hormone, polyamine, and phenol content to improve cell osmotic potential and to mitigate petal browning. Metabolomic data suggested the increased chilling resistance of Fm relies on in the plant being rich in a-linolenic acid, linoleic acid, as well as two amino acids, Phe and Trp, and has low levels of cinnamic acid and gramine in flowers compared to Fs. A higher abundance of glutathione disulfide and NADPH regulated by glutathione peroxidases and NADPH improved the ability of the cellular antioxidant and reduction-oxidation system stability in Fm;Additionally, the elevated levels of pyruvate, a-ketoglutaric acid, and oxaloacetic acid in Fm contributed to a significantly enhanced ATP production in mitochondria. Through Ka/Ks and gene expression analysis,four transcription factors, EVM0025036(bHLH), EVM0010639 and EVM0007275(AP2), and EVM0025908(bZIP) were identified that may contribute to the high cold tolerance of Fm. These adaptations highlight the intricate interplay between genetic and physiological processes that shape the survival strategies of plants in response to their specific ecological niches.展开更多
In the published version of our article(Shaji et al.,2024),in the last paragraph of the article,Hong Kong should be corrected to Hong Kong(China)and the repetition of Spain and Ireland in the same sentence need to be ...In the published version of our article(Shaji et al.,2024),in the last paragraph of the article,Hong Kong should be corrected to Hong Kong(China)and the repetition of Spain and Ireland in the same sentence need to be deleted.The correct sentence is as below.展开更多
Gypsum rocks are highly susceptible to mechanical deterioration under the coupled effects of wet-dry(W-D)cycles and flow rates,which significantly influence the stability of underground excavations.Despite extensive r...Gypsum rocks are highly susceptible to mechanical deterioration under the coupled effects of wet-dry(W-D)cycles and flow rates,which significantly influence the stability of underground excavations.Despite extensive research on the effects of W-D cycles,the coupling influence of flow rates and W-D cycles on gypsum rocks remains poorly understood.This study investigates the mechanical behavior and deterioration mechanisms of gypsum rocks subjected to varying W-D cycles and flow rate conditions.Axial compression tests,along with nuclear magnetic resonance(NMR)techniques,were employed to analyze the stress-strain response and microstructural changes.Based on the disturbed state concept(DSC)theory,a W-D deterioration model and a DSC-based constitutive model were developed to describe the degradation trends and mechanical responses of gypsum rocks under different conditions.The results demonstrate that key mechanical indices,elastic modulus,cohesion,uniaxial compressive strength(UCS),and internal friction angle,exhibit logarithmic declines with increasing W-D cycles,with higher flow rates accelerating the deterioration process.The theoretical models accurately capture the nonlinear compaction behavior,peak stress,and post-peak response of gypsum specimens.This study provides valuable insights for predicting the mechanical behavior of gypsum rocks and improving the stability assessments of underground structures under complex environmental conditions.展开更多
Low-valent sulfur oxy-acid salts(LVSOs)represent a category of oxygen-containing salts characterized by their potent reducing capabilities.Notably,sulfite,dithionite,and thiosulfate are prevalent reducing agents that ...Low-valent sulfur oxy-acid salts(LVSOs)represent a category of oxygen-containing salts characterized by their potent reducing capabilities.Notably,sulfite,dithionite,and thiosulfate are prevalent reducing agents that are readily available,cost-effective,and exhibit minimal ecological toxicity.These LVSOs have the ability to generate or promote the generation of strong oxidants or reductants,which makes them widely used in advanced oxidation processes(AOPs)and advanced reduction processes(ARPs).This article provides a comprehensive review of the recent advancements in AOPs and ARPs involving LVSOs,alongside an examination of the fundamental principles governing the generation of active species within these processes.LVSOs fulfill three primary functions in AOPs:Serving as sources of reactive oxygen species(ROS),auxiliary agents,and activators.Particular attention is devoted to elucidating the reaction mechanisms through which LVSOs,in conjunction with metal ions,metal oxides,ultraviolet light(UV),and ozone,produce potent oxidizing agents in both homogeneous and heterogeneous systems.Regarding ARPs,this review delineates the mechanisms by which LVSOs generate strong reducing agents,including hydrated electrons,hydrogen radicals,and sulfite radicals,under UV irradiation,while also exploring the interactions between these reductants and pollutants.The review identifies existing gaps within the current framework and proposes future research avenues to address these challenges.展开更多
Understanding the mechanical properties of coal-rock-bolt(CRB)combinations at high strain rates and the anchoring mechanism of bolts is crucial for ensuring the safety of coal mining operations.However,the dynamic beh...Understanding the mechanical properties of coal-rock-bolt(CRB)combinations at high strain rates and the anchoring mechanism of bolts is crucial for ensuring the safety of coal mining operations.However,the dynamic behaviors of these combinations,especially the mechanism of action of prestressed bolts,still need to be further investigated.This study carried out split Hopkinson pressure bar(SHPB)tests on three sets of coal-rock(CR),CRB,and coal-rock-prestressed bolt(CRPB)combinations with different interface angles(β=15°,30°,45°,and 60°).The dynamic properties of the combinations were analyzed based on the stress-strain curve,energy dissipation,dynamic strength,fractal dimension of cracks,and failure mode of bolts.The test results show that a larger β will affect the stress transfer and anti-sliding ability of CR,resulting in a decrease in CR strength.The anchoring force of the bolt effectively suppresses the slip feature of CRB at the yield stage.As the strain rate increases,CRB shows a more pronounced'sudden increase'in strength,and the bolt significantly enhances its dynamic strength.The prestressed bolts enhance the dynamic strength of CRPB while weaken the effect of β.The fractal dimension of the macrocracks increases with strain rate,with smaller variations in CRB and CRPB,indicating that the bolt reduces the complexity degree of CRB and CRPB.The anchoring force of CRB depends on bolt strength,which reduces the slip along the interface.The anchoring force of CRPB balances the coal-rock slip and suppresses crack formation,resulting in a more cohesive response under dynamic load.展开更多
The Yangchuling porphyry W-Mo deposit(YPWD),located in the Jiangnan porphyryskarn tungsten ore belt,is one of the most important and large-scale porphyry W-Mo deposits in South China.While previous zircon U-Pb and mol...The Yangchuling porphyry W-Mo deposit(YPWD),located in the Jiangnan porphyryskarn tungsten ore belt,is one of the most important and large-scale porphyry W-Mo deposits in South China.While previous zircon U-Pb and molybdenite Re-Os data suggest that Yangchuling WMo ore bodies formed almost simultaneously with granodiorite and monzogranitic porphyry at~150–144 Ma,their post emplacement history remains poorly understood,making their preservation status at depth uncertain.In this paper,new zircon and apatite(U-Th)/He and apatite fission track(ZHe,AHe and AFT,respectively)data of one hornfels and five intrusive rocks from a 1000-meter borehole are presented.These,together with new inverse thermal history models and previous geochronological data,help elucidate the post-diagenetic exhumation history and preservation status of the Yangchuling porphyry W-Mo deposit.In general,ZHe and AHe ages decrease gradually from the near surface downwards and have relatively little intra-sample variation,ranging from 133 to 73Ma and 67 to 25 Ma,respectively.All four granodiorites yield similar AFT ages that range from 63 to 55 Ma with mean track lengths varying from 12.2±0.7 to 12.6±0.5μm.Thermal history modelling indicates that the Yangchuling ore district experienced slow,monotonic cooling since the Cretaceous.Age-depth relationships are interpreted as recording~3.7±0.8 km of Cretaceous-recent exhumation in response to regional extension throughout South China thought to have been driven by subduction retreat of the Paleo-Pacific Plate.Comparison of estimated net exhumation and previous metallogenic depth of~4–5 km suggests that W-Mo ore bodies could still exist at depths of up to~1.3±0.8 km relative to Earth surface in the YPWD region.Preservation of the YPWD is attributed to the limited amount of regional denudation during the Late Cretaceous and Cenozoic.展开更多
Owing to anionic redox,cathode materials containing layered Li-rich Mn-based oxides(LLOs)are promising for the development of next-generation lithium-ion batteries(LIBs)with a large energy density(~500–600 Wh·kg...Owing to anionic redox,cathode materials containing layered Li-rich Mn-based oxides(LLOs)are promising for the development of next-generation lithium-ion batteries(LIBs)with a large energy density(~500–600 Wh·kg^(−1)).However,these LLOs are easily degraded during cycling,which limits their lifespan.So far,the degradation mechanism is still under debate.Herein,LLOs are post-treated through implantation with energetic Ti ion flux(Ti-LLO),which modifies the structure of LLOs both at the surface and within the bulk.Unlike the dominant R3m phase(73.24%)observed in LLOs,the phase structure of Ti-LLO is altered,with Li-rich C2/m accounting for 67.72%in the bulk,alongside the formation of a thin(approximately 2 nm),uniform,and continuous Li-Ti-O spinel layer at the surface.Apart from phase structure changes,chemical valence states of transition metals and O,as well as their evolution,are analyzed and compared to charge transport kinetics to elucidate their contributions to the enhanced discharge capacity in Ti-LLOs.Besides,the role of the Li-Ti-O spinel layer at the surface in providing anticorrosion protection at the interface of LLOs/electrolyte during cycling is evaluated.As a result,we demonstrate that a superhigh discharge capacity(335.3 mAh·g^(−1))at 0.1 C can be achieved,along with prolonged cycling stability(showing capacity retention of approximately 80%after 500 cycles at 1 C)through these modifications.Moreover,we confirmed the universality of the strategy by implanting other ions,which offers practical strategies for achieving high performance in LLO cathode materials through thermodynamics and kinetics pathways.展开更多
Surface space constraints and the associated massive carbon emissions present significant challenges to the sustainable development of megacities.Urban underground space(UUS)construction is expected to provide a pract...Surface space constraints and the associated massive carbon emissions present significant challenges to the sustainable development of megacities.Urban underground space(UUS)construction is expected to provide a practical approach for alleviating the space constraints of surface construction.However,indepth examinations of the overall UUS system to reveal carbon emissions in the complex matrix are lacking.This study demonstrates the vital role of UUS development in achieving carbon neutrality using a streamlined life-cycle assessment method.Carbon emissions and the mitigation potential of building underground spaces,metro systems,and geothermal energy sources are analyzed.The construction of underground spaces in buildings is the largest carbon emitter within the entire UUS system,releasing a considerable 547.2 Mt in 2020.However,geothermal carbon sequestration,a significant element of the UUS system,provided an unexpected and impressive contribution,sequestering 170 Mt of carbon in 2020.This study shows that UUS addresses the lack of space for urban development and is a lowcarbon method of urban construction.Therefore,developing low-carbon building technologies and improving the UUS development model is imperative to achieving better low-carbon balance.This helps to promote more coordinated and sustainable urban development.展开更多
BACKGROUND The discovery of induced pluripotent stem cells revolutionized regenerative medicine,providing a source for generating induced pluripotent stem cell-derived mesenchymal stem cells(iMSCs).AIM To evaluate and...BACKGROUND The discovery of induced pluripotent stem cells revolutionized regenerative medicine,providing a source for generating induced pluripotent stem cell-derived mesenchymal stem cells(iMSCs).AIM To evaluate and compare five iMSC differentiation protocols,assessing their efficiency,phenotypic characteristics,and functional properties relative to primary mesenchymal stem cells(MSCs).METHODS Five iMSC differentiation protocols were assessed:SB431542-based differentiation(iMSC1,iMSC3),an iMatrix-free method(iMSC2),growth factor supplementation(iMSC4),and embryoid body formation with retinoic acid(EB-iMSC).iMSC identity was confirmed according to the International Society for Cell&Gene Therapy 2006 criteria,requiring expression of surface markers(CD105,CD73,CD90)and absence of pluripotency markers.Functional assays were conducted to evaluate differentiation potential(osteogenic and adipogenic),proliferation,mitochondrial function,reactive oxygen species,senescence,and migration.RESULTS All iMSC types expressed MSC markers and lacked pluripotency markers.EBiMSC and iMSC2 showed enhanced osteogenesis(runt-related transcription factor 2;P≤0.01 and P≤0.0001,respectively),while adipogenic potential was reduced in iMSC2(Adipsin;P≤0.01)and EB-iMSC(Adipsin and peroxisome proliferatoractivated receptor gamma;P≤0.0001 and P≤0.01,respectively).Proliferation was comparable or superior to bone marrow MSCs,except in iMSC1,with iMSC4 showing the highest rate(MTT assay;P values ranged from 0.01 to 0.001).Despite reduced mitochondrial health in iMSC3 and iMSC4(P≤0.001),reactive oxygen species levels were lower in all iMSCs(P values ranged from 0.001 to 0.0001),and senescence was significantly reduced in all iMSCs with the exception of iMSC1(P values ranged from 0.01 to 0.0001).Migration was most reduced in iMSC4(P≤0.001 at 24 hours and P≤0.0001 at 48 hours).CONCLUSION While all protocols generated functional iMSCs,variations in differentiation,proliferation,and function emphasize the impact of protocol selection.These findings contribute to optimizing iMSC generation for research and clinical applications.展开更多
The fractured rock mass inherently exhibits uncertainty due to the presence of pre-existing discontinuities.In this study,a particle-based model incorporating the discrete fracture network(DFN)to elucidate the dynamic...The fractured rock mass inherently exhibits uncertainty due to the presence of pre-existing discontinuities.In this study,a particle-based model incorporating the discrete fracture network(DFN)to elucidate the dynamic tensile responses and asso-ciated uncertainty of rock mass.At first,the particle-based model was used synthesize the intact rock and split Hopkinson pressure bar(SHPB)system,while the fractures were represented using the smooth fracture model(SJM).Subsequently,the samples of the fractured rock mass with varying joint geometrical configurations were conducted the dynamic tensile test using the numerical SHPB system.The simulated results demonstrate a gradual decrease in dynamic tensile strength(TS)with increasing fracture intensity and fracture length,which can be effectively described by nonlinear exponential func-tions.Additionally,the fracture orientation significantly influences the dynamic TS,however,the anisotropic characteristics gradually diminish as the deviation angle approaches 90°.Furthermore,as fracture intensity and fracture length increase,the dynamic TS variability also rises steadily.However,no noticeable pattern is seen when considering cases with varying fracture orientations.When subjected to SHPB loading,the fractured rock mass primarily exhibits a combined tensile-shear failure mode,contrasting with the pure tensile failure mode exhibited by the intact rock.These findings contribute signifi-cantly to comprehending the dynamic tensile responses of the fractured rock mass and can further enhance the stability analysis of in-situ rock engineering.展开更多
文摘Software security poses substantial risks to our society because software has become part of our life. Numerous techniques have been proposed to resolve or mitigate the impact of software security issues. Among them, software testing and analysis are two of the critical methods, which significantly benefit from the advancements in deep learning technologies. Due to the successful use of deep learning in software security, recently,researchers have explored the potential of using large language models(LLMs) in this area. In this paper, we systematically review the results focusing on LLMs in software security. We analyze the topics of fuzzing, unit test, program repair, bug reproduction, data-driven bug detection, and bug triage. We deconstruct these techniques into several stages and analyze how LLMs can be used in the stages. We also discuss the future directions of using LLMs in software security, including the future directions for the existing use of LLMs and extensions from conventional deep learning research.
文摘ChatGPT is a powerful artificial intelligence(AI)language model that has demonstrated significant improvements in various natural language processing(NLP) tasks. However, like any technology, it presents potential security risks that need to be carefully evaluated and addressed. In this survey, we provide an overview of the current state of research on security of using ChatGPT, with aspects of bias, disinformation, ethics, misuse,attacks and privacy. We review and discuss the literature on these topics and highlight open research questions and future directions.Through this survey, we aim to contribute to the academic discourse on AI security, enriching the understanding of potential risks and mitigations. We anticipate that this survey will be valuable for various stakeholders involved in AI development and usage, including AI researchers, developers, policy makers, and end-users.
基金supported by the Australian Research Council Centre of Excellence in Optical Microcombs for Breakthrough Science COMBS(CE230100006)the Australian Research Council grants DP220100488 and DE230100964funded by the Australian Government.
文摘Lithium niobate(LN)has remained at the forefront of academic research and industrial applications due to its rich material properties,which include second-order nonlinear optic,electro-optic,and piezoelectric properties.A further aspect of LN’s versatility stems from the ability to engineer ferroelectric domains with micro and even nano-scale precision in LN,which provides an additional degree of freedom to design acoustic and optical devices with improved performance and is only possible in a handful of other materials.In this review paper,we provide an overview of the domain engineering techniques developed for LN,their principles,and the typical domain size and pattern uniformity they provide,which is important for devices that require high-resolution domain patterns with good reproducibility.It also highlights each technique's benefits,limitations,and adaptability for an application,along with possible improvements and future advancement prospects.Further,the review provides a brief overview of domain visualization methods,which is crucial to gain insights into domain quality/shape and explores the adaptability of the proposed domain engineering methodologies for the emerging thin-film lithium niobate on an insulator platform,which creates opportunities for developing the next generation of compact and scalable photonic integrated circuits and high frequency acoustic devices.
基金supported by the National Natural Science Foundation of China(No.21876039)Y.Yao acknowledges the scholarship support from the China Scholarship Council(No.202106695010)Partial support from the Australian Research Council for DP230102406 is also acknowledged.
文摘Catalytic oxidation of organic pollutants is a well-known and effective technique for pollutant abatement.Unfortunately,this method is significantly hindered in practical applications by the lowefficiency and difficult recovery of the catalysts in a powdery form.Herein,a three-dimensional(3D)framework of Fe-incorporated Ni_(3)S_(2)nanosheets in-situ grown on Ni foam(Fe-Ni_(3)S_(2)@NF)was fabricated by a facile two-step hydrothermal process and applied to trigger peroxymonosulfate(PMS)oxidation of organic compounds inwater.A homogeneous growth environment enabled the uniform and scalable growth of Fe-Ni_(3)S_(2)nanosheets on the Ni foam.Fe-Ni_(3)S_(2)@NF possessed outstanding activity and durability in activating PMS,as it effectively facilitated electron transfer from organic pollutants to PMS.Fe-Ni_(3)S_(2)@NF initially supplied electrons to PMS,causing the catalyst to undergo oxidation,and subsequently accepted electrons from organic compounds,returning to its initial state.The introduction of Fe into the Ni_(3)S_(2)lattice enhanced electrical conductivity,promoting mediated electron transfer between PMS and organic compounds.The 3D conductive Ni foam provided an ideal platform for the nucleation and growth of Fe-Ni_(3)S_(2),accelerating pollutant abatement due to its porous structure and high conductivity.Furthermore,its monolithic nature simplified the catalyst recycling process.A continuous flow packed-bed reactor by encapsulating Fe-Ni_(3)S_(2)@NF catalyst achieved complete pollutant abatement with continuous operation for 240 h,highlighting its immense potential for practical environmental remediation.This study presents a facile synthesis method for creating a novel type of monolithic catalyst with high activity and durability for decontamination through Fenton-like processes.
基金The National Natural Science Foundation of China(W2431048)The Science and Technology Research Program of Chongqing Municipal Education Commission,China(KJZDK202300807)The Chongqing Natural Science Foundation,China(CSTB2024NSCQQCXMX0052).
文摘This paper addresses the consensus problem of nonlinear multi-agent systems subject to external disturbances and uncertainties under denial-ofservice(DoS)attacks.Firstly,an observer-based state feedback control method is employed to achieve secure control by estimating the system's state in real time.Secondly,by combining a memory-based adaptive eventtriggered mechanism with neural networks,the paper aims to approximate the nonlinear terms in the networked system and efficiently conserve system resources.Finally,based on a two-degree-of-freedom model of a vehicle affected by crosswinds,this paper constructs a multi-unmanned ground vehicle(Multi-UGV)system to validate the effectiveness of the proposed method.Simulation results show that the proposed control strategy can effectively handle external disturbances such as crosswinds in practical applications,ensuring the stability and reliable operation of the Multi-UGV system.
基金funding support from the National Natural Science Foundation of China(Grant No.52374119)the opening fund of State Key Laboratory of Coal Mine Disaster Dynamics and Control(Grant No.2011DA105827-FW202209)the opening fund of State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure,East China Jiaotong University(Grant No.HJGZ2023103).
文摘Understanding the dynamic responses of hard rocks is crucial during deep mining and tunneling activities and when constructing nuclear waste repositories. However, the response of deep massive rocks with openings of different shapes and orientations to dynamic loading is not well understood. Therefore, this study investigates the dynamic responses of hard rocks of deep underground excavation activities. Split Hopkins Pressure Bar (SHPB) tests on granite with holes of different shapes (rectangle, circle, vertical ellipse (elliptical short (ES) axis parallel to the impact load direction), and horizontal ellipse (elliptical long (EL) axis parallel to the impact load direction)) were carried out. The influence of hole shape and location on the dynamic responses was analyzed to reveal the rocks' dynamic strengths and cracking characteristics. We used the ResNet18 (convolutional neural network-based) network to recognize crack types using high-speed photographs. Moreover, a prediction model for the stress-strain response of rocks with different openings was established using Deep Neural Network (DNN). The results show that the dynamic strengths of the granite with EL and ES holes are the highest and lowest, respectively. The strength-weakening coefficient decreases first and then increases with an increase of thickness-span ratio (h/L). The weakening of the granite with ES holes is the most obvious. The ResNet18 network can improve the analyzing efficiency of the cracking mechanism, and the trained model's recognition accuracy reaches 99%. Finally, the dynamic stress-strain prediction model can predict the complete stress-strain curve well, with an accuracy above 85%.
基金funding from National Science Foundation of China(52202337 and 22178015)the Young Taishan Scholars Program of Shandong Province(tsqn202211082)+1 种基金Natural Science Foundation of Shandong Province(ZR2023MB051)Independent Innovation Research Project of China University of Petroleum(East China)(22CX06023A).
文摘Layer-structured Ruddlesden–Popper(RP)perovskites(RPPs)with decent stability have captured the imagination of the photovoltaic research community and bring hope for boosting the development of perovskite solar cell(PSC)technology.However,two-dimensional(2D)or quasi-2D RP PSCs are encountered with some challenges of the large exciton binding energy,blocked charge transport and poor film quality,which restrict their photovoltaic performance.Fortunately,these issues can be readily resolved by rationally designing spacer cations of RPPs.This review mainly focuses on how to design the molecular structures of organic spacers and aims to endow RPPs with outstanding photovoltaic applications.We firstly elucidated the important roles of organic spacers in impacting crystallization kinetics,charge transporting ability and stability of RPPs.Then we brought three aspects to attention for designing organic spacers.Finally,we presented the specific molecular structure design strategies for organic spacers of RPPs aiming to improve photovoltaic performance of RP PSCs.These proposed strategies in this review will provide new avenues to develop novel organic spacers for RPPs and advance the development of RPP photovoltaic technology for future applications.
基金supported by the Mineral Exploration Cooperative Research Centre whose activities are funded by the Australian Government’s Cooperative Research Centre Program.This is MinEx CRC Document 2025/06.
文摘The Ediacaran-Cambrian Petermann Orogen is a dextral transpressional orogen exposed in central Australia,which facilitated the exhumation of a high-pressure core and the deformation of the Neoproterozoic-Palaeozoic Amadeus Basin.Several studies have investigated the metamorphic and deformational evolution of the Petermann Orogen;however,the spatiotemporal variation of the deformation and cooling history is yet to be fully understood.In situ muscovite and biotite Rb-Sr geochronology,in combination with Ti-in-quartz thermometry is applied to map the spatiotemporal deformation and cooling patterns of the northern part of the Petermann Orogen.Interpreted muscovite Rb-Sr growth ages obtained from samples in the Petermann Nappe Complex(PNC),range between c.598 Ma and 565 Ma,which correlate with the timing of deformation during the 600-520 Ma Petermann Orogeny.Interpreted muscovite and biotite cooling ages are younger in the east of the PNC(c.556-541 Ma)and broadly correlate with the regional pattern of crustal heat production,suggesting that the geothermal gradient had a significant control on the timing and duration of cooling.Biotite Rb-Sr cooling ages between c.555 Ma and 497 Ma for the orogenic core show no correlation with high heat production areas,however,differences in exhumed crustal levels across the Petermann Orogen are observed:high-P granulite facies rocks in the orogenic core vs middle-upper crustal rocks in the PNC,indicating that at least part of the spatiotemporal variation of cooling ages can be attributed to differential exhumation during the Petermann Orogeny.Hence,crustal heat production and differential exhumation were likely the main controlling factors on the duration and variation of cooling rates in the Petermann Orogen.
基金the National Natural Science Foundation of China(No.52374150)the Key Science and Technology Project of Ministry of Emergency Management of the People’s Republic of China(No.2024EMST141405).
文摘The stability of underground tunnel roofs is strongly influenced by wedge blocks formed by complex joint networks.The mechanical behavior and failure mechanisms of different roof wedge blocks in arched holes were investigated under biaxial stress conditions.The crack evolution and failure modes of the specimens were analyzed through acoustic emission(AE),digital image correlation(DIC),and discrete element method(DEM).Results show significant variations in mechanical properties:specimens T1(extremely unstable triangular)and T2(extremely unstable quadrilateral)exhibited higher strength than T3(extremely stable triangular)and T4(extremely stable quadrilateral),while support more effectively enhanced the strength of T3 and T4.Failure modes were classified as rock-dominated,wedgedominated,or co-dominated.Cracks typically initiated near the wedge and propagated outward.Unsupported specimens developed tensile cracks at the hole bottom,shear cracks at the sides,and mixed cracks along wedge boundaries,whereas supported specimens mainly exhibited cracks at the roof and sides.Stress analysis indicated that unsupported conditions induced high stress differences,promoting localized shear failure.Wedge geometry significantly affected shear stress redistribution at the roof.These findings highlight the critical role of support and wedge block geometry in controlling stress dis-tribution and failure mechanisms in arched tunnels.
基金supports from the National Natural Science Foundation of China(Nos.22478426 and 22278436)Young Elite Scientists Sponsorship Program by BAST(No.1101020370359)Science Foundation of China University of Petroleum,Beijing(No.2462021QNXZ009)。
文摘Advanced oxidation processes(AOPs)governed by peroxide activation to produce highly oxidative active species have been extensively explored for environmental remediation.Nevertheless,the low diffusion rates,inadequate interactions of the reactants,and limited active site exposure hinder treatment efficiency.Porous carbocatalysts with high specific surface area,tunable pore size,and programmable active sites demonstrate outstanding performance in activating diverse types of peroxides to generate active species for treatment of aqueous organic pollutants.The pore-rich structures enhance reaction kinetics for peroxide activation by facilitating diffusion of the reactants and their interactions.Additionally,the structural flexibility of porous structures favors the accommodation of highly dispersed metal species and allows for precise tuning of the microenvironment around the active sites,which further enhances the catalytic activity.This review critically summarizes the recent research progress in the applications of engineered porous carbocatalysts for peroxide activation and outlines the prevailing pore construction methods in carbocatalysts.Moreover,engineering strategies to regulate the mass transfer efficiency and fine-tune the microenvironment around the active sites are systematically addressed to enhance their catalytic peroxide activation performances.Challenges and future research opportunities pertaining to the design,optimization,mechanistic investigation,and practical application of porous carbocatalysts in peroxide activation are also proposed.
基金supported by the National Natural Science Foundation of China(Grant NO.32360307).
文摘Long-term niche differentiation will lead to the evolution of diverse adaptive strategies for species in diverse environments. The present study selected two Forsythia species, Forsythia mandshurica(Fm)-which naturally occurs in a cold temperate zone and Forsythia suspensa(Fs)-which thrives in a warm temperate zone-to reveal their differential chilling defense mechanisms by integrating morpho-physiological,transcriptomic, and metabolomic data. Transcriptome results show that Fm has evolved in a series of adaptive mechanisms designed to help the plants to cope with chilling stress by enhancing sugar, amino acid, hormone, polyamine, and phenol content to improve cell osmotic potential and to mitigate petal browning. Metabolomic data suggested the increased chilling resistance of Fm relies on in the plant being rich in a-linolenic acid, linoleic acid, as well as two amino acids, Phe and Trp, and has low levels of cinnamic acid and gramine in flowers compared to Fs. A higher abundance of glutathione disulfide and NADPH regulated by glutathione peroxidases and NADPH improved the ability of the cellular antioxidant and reduction-oxidation system stability in Fm;Additionally, the elevated levels of pyruvate, a-ketoglutaric acid, and oxaloacetic acid in Fm contributed to a significantly enhanced ATP production in mitochondria. Through Ka/Ks and gene expression analysis,four transcription factors, EVM0025036(bHLH), EVM0010639 and EVM0007275(AP2), and EVM0025908(bZIP) were identified that may contribute to the high cold tolerance of Fm. These adaptations highlight the intricate interplay between genetic and physiological processes that shape the survival strategies of plants in response to their specific ecological niches.
文摘In the published version of our article(Shaji et al.,2024),in the last paragraph of the article,Hong Kong should be corrected to Hong Kong(China)and the repetition of Spain and Ireland in the same sentence need to be deleted.The correct sentence is as below.
基金Projects(52378392,52478390)supported by the National Natural Science Foundation of ChinaProject(2024J08213)supported by the Natural Science Foundation of Fujian Province,China+1 种基金Project(00387088)supported by the“Foal Eagle Program”Youth Top-notch Talent Project of Fujian Province,ChinaProject(GY-Z23072)supported by the Scientific Research Foundation of Fujian University of Technology,China。
文摘Gypsum rocks are highly susceptible to mechanical deterioration under the coupled effects of wet-dry(W-D)cycles and flow rates,which significantly influence the stability of underground excavations.Despite extensive research on the effects of W-D cycles,the coupling influence of flow rates and W-D cycles on gypsum rocks remains poorly understood.This study investigates the mechanical behavior and deterioration mechanisms of gypsum rocks subjected to varying W-D cycles and flow rate conditions.Axial compression tests,along with nuclear magnetic resonance(NMR)techniques,were employed to analyze the stress-strain response and microstructural changes.Based on the disturbed state concept(DSC)theory,a W-D deterioration model and a DSC-based constitutive model were developed to describe the degradation trends and mechanical responses of gypsum rocks under different conditions.The results demonstrate that key mechanical indices,elastic modulus,cohesion,uniaxial compressive strength(UCS),and internal friction angle,exhibit logarithmic declines with increasing W-D cycles,with higher flow rates accelerating the deterioration process.The theoretical models accurately capture the nonlinear compaction behavior,peak stress,and post-peak response of gypsum specimens.This study provides valuable insights for predicting the mechanical behavior of gypsum rocks and improving the stability assessments of underground structures under complex environmental conditions.
基金supported by Natural Science Foundation of China(Nos.52070133,42107073,42477075)Natural Science Foundation of Sichuan Province(No.2024NSFSC0130)+2 种基金the Sichuan Science and Technology Program(No.2024NSFTD0014)Key Laboratory of Jiangxi Province for Persistent Pollutants Prevention Control and Resource Reuse(No.2023SSY02061)Key R&D Program of Heilongjiang Province(No.2023ZX02C01)。
文摘Low-valent sulfur oxy-acid salts(LVSOs)represent a category of oxygen-containing salts characterized by their potent reducing capabilities.Notably,sulfite,dithionite,and thiosulfate are prevalent reducing agents that are readily available,cost-effective,and exhibit minimal ecological toxicity.These LVSOs have the ability to generate or promote the generation of strong oxidants or reductants,which makes them widely used in advanced oxidation processes(AOPs)and advanced reduction processes(ARPs).This article provides a comprehensive review of the recent advancements in AOPs and ARPs involving LVSOs,alongside an examination of the fundamental principles governing the generation of active species within these processes.LVSOs fulfill three primary functions in AOPs:Serving as sources of reactive oxygen species(ROS),auxiliary agents,and activators.Particular attention is devoted to elucidating the reaction mechanisms through which LVSOs,in conjunction with metal ions,metal oxides,ultraviolet light(UV),and ozone,produce potent oxidizing agents in both homogeneous and heterogeneous systems.Regarding ARPs,this review delineates the mechanisms by which LVSOs generate strong reducing agents,including hydrated electrons,hydrogen radicals,and sulfite radicals,under UV irradiation,while also exploring the interactions between these reductants and pollutants.The review identifies existing gaps within the current framework and proposes future research avenues to address these challenges.
基金Financial support from the National Natural Science Foundation of China(Grant No.52374119)the Province Education Department of Liaoning(Grant No.LJ212410146068)the opening fund of State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure,East China Jiaotong University(Grant No.HJGZ2023103).
文摘Understanding the mechanical properties of coal-rock-bolt(CRB)combinations at high strain rates and the anchoring mechanism of bolts is crucial for ensuring the safety of coal mining operations.However,the dynamic behaviors of these combinations,especially the mechanism of action of prestressed bolts,still need to be further investigated.This study carried out split Hopkinson pressure bar(SHPB)tests on three sets of coal-rock(CR),CRB,and coal-rock-prestressed bolt(CRPB)combinations with different interface angles(β=15°,30°,45°,and 60°).The dynamic properties of the combinations were analyzed based on the stress-strain curve,energy dissipation,dynamic strength,fractal dimension of cracks,and failure mode of bolts.The test results show that a larger β will affect the stress transfer and anti-sliding ability of CR,resulting in a decrease in CR strength.The anchoring force of the bolt effectively suppresses the slip feature of CRB at the yield stage.As the strain rate increases,CRB shows a more pronounced'sudden increase'in strength,and the bolt significantly enhances its dynamic strength.The prestressed bolts enhance the dynamic strength of CRPB while weaken the effect of β.The fractal dimension of the macrocracks increases with strain rate,with smaller variations in CRB and CRPB,indicating that the bolt reduces the complexity degree of CRB and CRPB.The anchoring force of CRB depends on bolt strength,which reduces the slip along the interface.The anchoring force of CRPB balances the coal-rock slip and suppresses crack formation,resulting in a more cohesive response under dynamic load.
基金supported by the National Natural Science Foundation of China(Nos.42162013,42002095)the Foundation of State Key Laboratory of Nuclear Resources and Environment(Nos.2022NRE34,NRE2021-01)+1 种基金Jiangxi Provincial Natural Science Foundation(Nos.20242BAB26048,20242BAB25178)Fund of National Key Laboratory of Science and Technology on Remote Sensing Information and imagery Analysis,Beijing Research Institute of Uranium Geology(No.6142A01210405)。
文摘The Yangchuling porphyry W-Mo deposit(YPWD),located in the Jiangnan porphyryskarn tungsten ore belt,is one of the most important and large-scale porphyry W-Mo deposits in South China.While previous zircon U-Pb and molybdenite Re-Os data suggest that Yangchuling WMo ore bodies formed almost simultaneously with granodiorite and monzogranitic porphyry at~150–144 Ma,their post emplacement history remains poorly understood,making their preservation status at depth uncertain.In this paper,new zircon and apatite(U-Th)/He and apatite fission track(ZHe,AHe and AFT,respectively)data of one hornfels and five intrusive rocks from a 1000-meter borehole are presented.These,together with new inverse thermal history models and previous geochronological data,help elucidate the post-diagenetic exhumation history and preservation status of the Yangchuling porphyry W-Mo deposit.In general,ZHe and AHe ages decrease gradually from the near surface downwards and have relatively little intra-sample variation,ranging from 133 to 73Ma and 67 to 25 Ma,respectively.All four granodiorites yield similar AFT ages that range from 63 to 55 Ma with mean track lengths varying from 12.2±0.7 to 12.6±0.5μm.Thermal history modelling indicates that the Yangchuling ore district experienced slow,monotonic cooling since the Cretaceous.Age-depth relationships are interpreted as recording~3.7±0.8 km of Cretaceous-recent exhumation in response to regional extension throughout South China thought to have been driven by subduction retreat of the Paleo-Pacific Plate.Comparison of estimated net exhumation and previous metallogenic depth of~4–5 km suggests that W-Mo ore bodies could still exist at depths of up to~1.3±0.8 km relative to Earth surface in the YPWD region.Preservation of the YPWD is attributed to the limited amount of regional denudation during the Late Cretaceous and Cenozoic.
基金supported by the National Key Research and Development Program of China(2022YFB2502000)the National Natural Science Foundation of China(52201277,52207244,52207245)+1 种基金the Xi'an Young Talent Lifting Program(959202413060)the National Outstanding Youth Foundation of China(52125104).
文摘Owing to anionic redox,cathode materials containing layered Li-rich Mn-based oxides(LLOs)are promising for the development of next-generation lithium-ion batteries(LIBs)with a large energy density(~500–600 Wh·kg^(−1)).However,these LLOs are easily degraded during cycling,which limits their lifespan.So far,the degradation mechanism is still under debate.Herein,LLOs are post-treated through implantation with energetic Ti ion flux(Ti-LLO),which modifies the structure of LLOs both at the surface and within the bulk.Unlike the dominant R3m phase(73.24%)observed in LLOs,the phase structure of Ti-LLO is altered,with Li-rich C2/m accounting for 67.72%in the bulk,alongside the formation of a thin(approximately 2 nm),uniform,and continuous Li-Ti-O spinel layer at the surface.Apart from phase structure changes,chemical valence states of transition metals and O,as well as their evolution,are analyzed and compared to charge transport kinetics to elucidate their contributions to the enhanced discharge capacity in Ti-LLOs.Besides,the role of the Li-Ti-O spinel layer at the surface in providing anticorrosion protection at the interface of LLOs/electrolyte during cycling is evaluated.As a result,we demonstrate that a superhigh discharge capacity(335.3 mAh·g^(−1))at 0.1 C can be achieved,along with prolonged cycling stability(showing capacity retention of approximately 80%after 500 cycles at 1 C)through these modifications.Moreover,we confirmed the universality of the strategy by implanting other ions,which offers practical strategies for achieving high performance in LLO cathode materials through thermodynamics and kinetics pathways.
基金supported by the Shenzhen Science and Technology Plan(JCYJ20190808123013260).
文摘Surface space constraints and the associated massive carbon emissions present significant challenges to the sustainable development of megacities.Urban underground space(UUS)construction is expected to provide a practical approach for alleviating the space constraints of surface construction.However,indepth examinations of the overall UUS system to reveal carbon emissions in the complex matrix are lacking.This study demonstrates the vital role of UUS development in achieving carbon neutrality using a streamlined life-cycle assessment method.Carbon emissions and the mitigation potential of building underground spaces,metro systems,and geothermal energy sources are analyzed.The construction of underground spaces in buildings is the largest carbon emitter within the entire UUS system,releasing a considerable 547.2 Mt in 2020.However,geothermal carbon sequestration,a significant element of the UUS system,provided an unexpected and impressive contribution,sequestering 170 Mt of carbon in 2020.This study shows that UUS addresses the lack of space for urban development and is a lowcarbon method of urban construction.Therefore,developing low-carbon building technologies and improving the UUS development model is imperative to achieving better low-carbon balance.This helps to promote more coordinated and sustainable urban development.
文摘BACKGROUND The discovery of induced pluripotent stem cells revolutionized regenerative medicine,providing a source for generating induced pluripotent stem cell-derived mesenchymal stem cells(iMSCs).AIM To evaluate and compare five iMSC differentiation protocols,assessing their efficiency,phenotypic characteristics,and functional properties relative to primary mesenchymal stem cells(MSCs).METHODS Five iMSC differentiation protocols were assessed:SB431542-based differentiation(iMSC1,iMSC3),an iMatrix-free method(iMSC2),growth factor supplementation(iMSC4),and embryoid body formation with retinoic acid(EB-iMSC).iMSC identity was confirmed according to the International Society for Cell&Gene Therapy 2006 criteria,requiring expression of surface markers(CD105,CD73,CD90)and absence of pluripotency markers.Functional assays were conducted to evaluate differentiation potential(osteogenic and adipogenic),proliferation,mitochondrial function,reactive oxygen species,senescence,and migration.RESULTS All iMSC types expressed MSC markers and lacked pluripotency markers.EBiMSC and iMSC2 showed enhanced osteogenesis(runt-related transcription factor 2;P≤0.01 and P≤0.0001,respectively),while adipogenic potential was reduced in iMSC2(Adipsin;P≤0.01)and EB-iMSC(Adipsin and peroxisome proliferatoractivated receptor gamma;P≤0.0001 and P≤0.01,respectively).Proliferation was comparable or superior to bone marrow MSCs,except in iMSC1,with iMSC4 showing the highest rate(MTT assay;P values ranged from 0.01 to 0.001).Despite reduced mitochondrial health in iMSC3 and iMSC4(P≤0.001),reactive oxygen species levels were lower in all iMSCs(P values ranged from 0.001 to 0.0001),and senescence was significantly reduced in all iMSCs with the exception of iMSC1(P values ranged from 0.01 to 0.0001).Migration was most reduced in iMSC4(P≤0.001 at 24 hours and P≤0.0001 at 48 hours).CONCLUSION While all protocols generated functional iMSCs,variations in differentiation,proliferation,and function emphasize the impact of protocol selection.These findings contribute to optimizing iMSC generation for research and clinical applications.
基金supported by the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(2019ZT08G315)the National Natural Science Foundation of China(52304091,52004162 and 52274089)+1 种基金the Research Project of Education Department of Hunan Province(22B0427)the China postdoctoral science foundation(2023M741047).
文摘The fractured rock mass inherently exhibits uncertainty due to the presence of pre-existing discontinuities.In this study,a particle-based model incorporating the discrete fracture network(DFN)to elucidate the dynamic tensile responses and asso-ciated uncertainty of rock mass.At first,the particle-based model was used synthesize the intact rock and split Hopkinson pressure bar(SHPB)system,while the fractures were represented using the smooth fracture model(SJM).Subsequently,the samples of the fractured rock mass with varying joint geometrical configurations were conducted the dynamic tensile test using the numerical SHPB system.The simulated results demonstrate a gradual decrease in dynamic tensile strength(TS)with increasing fracture intensity and fracture length,which can be effectively described by nonlinear exponential func-tions.Additionally,the fracture orientation significantly influences the dynamic TS,however,the anisotropic characteristics gradually diminish as the deviation angle approaches 90°.Furthermore,as fracture intensity and fracture length increase,the dynamic TS variability also rises steadily.However,no noticeable pattern is seen when considering cases with varying fracture orientations.When subjected to SHPB loading,the fractured rock mass primarily exhibits a combined tensile-shear failure mode,contrasting with the pure tensile failure mode exhibited by the intact rock.These findings contribute signifi-cantly to comprehending the dynamic tensile responses of the fractured rock mass and can further enhance the stability analysis of in-situ rock engineering.
