Graph Neural Networks(GNNs)have proven highly effective for graph classification across diverse fields such as social networks,bioinformatics,and finance,due to their capability to learn complex graph structures.Howev...Graph Neural Networks(GNNs)have proven highly effective for graph classification across diverse fields such as social networks,bioinformatics,and finance,due to their capability to learn complex graph structures.However,despite their success,GNNs remain vulnerable to adversarial attacks that can significantly degrade their classification accuracy.Existing adversarial attack strategies primarily rely on label information to guide the attacks,which limits their applicability in scenarios where such information is scarce or unavailable.This paper introduces an innovative unsupervised attack method for graph classification,which operates without relying on label information,thereby enhancing its applicability in a broad range of scenarios.Specifically,our method first leverages a graph contrastive learning loss to learn high-quality graph embeddings by comparing different stochastic augmented views of the graphs.To effectively perturb the graphs,we then introduce an implicit estimator that measures the impact of various modifications on graph structures.The proposed strategy identifies and flips edges with the top-K highest scores,determined by the estimator,to maximize the degradation of the model’s performance.In addition,to defend against such attack,we propose a lightweight regularization-based defense mechanism that is specifically tailored to mitigate the structural perturbations introduced by our attack strategy.It enhances model robustness by enforcing embedding consistency and edge-level smoothness during training.We conduct experiments on six public TU graph classification datasets:NCI1,NCI109,Mutagenicity,ENZYMES,COLLAB,and DBLP_v1,to evaluate the effectiveness of our attack and defense strategies.Under an attack budget of 3,the maximum reduction in model accuracy reaches 6.67%on the Graph Convolutional Network(GCN)and 11.67%on the Graph Attention Network(GAT)across different datasets,indicating that our unsupervised method induces degradation comparable to state-of-the-art supervised attacks.Meanwhile,our defense achieves the highest accuracy recovery of 3.89%(GCN)and 5.00%(GAT),demonstrating improved robustness against structural perturbations.展开更多
The risk of flammability is an unavoidable issue for gel polymer electrolytes(GPEs).Usually,flameretardant solvents are necessary to be used,but most of them would react with anode/cathode easily and cause serious int...The risk of flammability is an unavoidable issue for gel polymer electrolytes(GPEs).Usually,flameretardant solvents are necessary to be used,but most of them would react with anode/cathode easily and cause serious interfacial instability,which is a big challenge for design and application of nonflammable GPEs.Here,a nonflammable GPE(SGPE)is developed by in situ polymerizing trifluoroethyl methacrylate(TFMA)monomers with flame-retardant triethyl phosphate(TEP)solvents and LiTFSI–LiDFOB dual lithium salts.TEP is strongly anchored to PTFMA matrix via polarity interaction between-P=O and-CH_(2)CF_(3).It reduces free TEP molecules,which obviously mitigates interfacial reactions,and enhances flame-retardant performance of TEP surprisingly.Anchored TEP molecules are also inhibited in solvation of Li^(+),leading to anion-dominated solvation sheath,which creates inorganic-rich solid electrolyte interface/cathode electrolyte interface layers.Such coordination structure changes Li^(+)transport from sluggish vehicular to fast structural transport,raising ionic conductivity to 1.03 mS cm^(-1) and transfer number to 0.41 at 30℃.The Li|SGPE|Li cell presents highly reversible Li stripping/plating performance for over 1000 h at 0.1 mA cm^(−2),and 4.2 V LiCoO_(2)|SGPE|Li battery delivers high average specific capacity>120 mAh g^(−1) over 200 cycles.This study paves a new way to make nonflammable GPE that is compatible with Li metal anode.展开更多
One of the most prevalent malignant tumors worldwide,stomach cancer still has a high incidence and fatality rate in China,and the number of young people developing early-onset gastric cancer is steadily increasing.The...One of the most prevalent malignant tumors worldwide,stomach cancer still has a high incidence and fatality rate in China,and the number of young people developing early-onset gastric cancer is steadily increasing.The 5-year survival rate of stomach cancer is typically 30%–35%,the prognosis is bad,the patients’quality of life is low,and the progression of advanced gastric cancer cannot be effectively managed despite the use of surgical surgery,chemotherapy,and other medicines.We urgently need molecular biomarkers with high specificity and sensitivity to increase the early gastric cancer detection rate,extend patient survival,and improve patient quality of life.The initial diagnosis of gastric cancer primarily depends on gastroscopy and biopsy,and invasive procedures cause significant discomfort to patients.Similar to this,treating advanced and metastatic stomach cancer is a pressing issue that requires attention.More and more immune checkpoint molecules have been discovered,and corresponding inhibitors are gradually being applied to clinical diagnosis and treatment.Recently,some non-coding RNAs have begun to be used as new targets for the treatment of gastric cancer.Some non-coding RNAs are highly present in the serum or urine of gastric cancer patients and can be used as diagnostic markers or prognostic indicators.Many clinical trials targeting non-coding RNAs have also shown good therapeutic effects.In general,targeting non-coding RNAs has shown good therapeutic effects.The biomarkers for gastric cancer detection and treatment are reviewed in this article,focusing on the new non-coding RNAs used in diagnosis,prognosis,and treatment.Patients with stomach cancer should have access to more precise and efficient diagnosis and treatment choices as a result of ongoing technological advancements and thorough research.展开更多
KanCell is a deep learning model based on Kolmogorov-Arnold networks(KAN)designed to enhance cellular heterogeneity analysis by integrating single-cell RNA sequencing and spatial transcriptomics(ST)data.ST technologie...KanCell is a deep learning model based on Kolmogorov-Arnold networks(KAN)designed to enhance cellular heterogeneity analysis by integrating single-cell RNA sequencing and spatial transcriptomics(ST)data.ST technologies provide insights into gene expression within tissue context,revealing cellular interactions and microenvironments.To fully leverage this potential,effective computational models are crucial.We evaluate KanCell on both simulated and real datasets from technologies such as STARmap,Slide-seq,Visium,and Spatial Transcriptomics.Our results demonstrate that KanCell outperforms existing methods across metrics like PCC,SSIM,COSSIM,RMSE,JSD,ARS,and ROC,with robust performance under varying cell numbers and background noise.Real-world applications on human lymph nodes,hearts,melanoma,breast cancer,dorsolateral prefrontal cortex,and mouse embryo brains confirmed its reliability.Compared with traditional approaches,KanCell effectively captures non-linear relationships and optimizes computational efficiency through KAN,providing an accurate and efficient tool for ST.By improving data accuracy and resolving cell type composition,KanCell reveals cellular heterogeneity,clarifies disease microenvironments,and identifies therapeutic targets,addressing complex biological challenges.展开更多
Under the dual-carbon background,the technological updating of traditional high-energy-consuming equipment should not be delayed,and the problem of reactor energy consumption should not be ignored.Therefore,this study...Under the dual-carbon background,the technological updating of traditional high-energy-consuming equipment should not be delayed,and the problem of reactor energy consumption should not be ignored.Therefore,this study is based on computational fluid dynamics(CFD)theory to simulate the spiral stirred reactor with different design parameters(distance of paddle from bottom surface to reactor height ratio h1/H,diameter of stirring paddle to reactor diameter ratio Ds/D,length of blade section to reactor height ratio Ls/H).It was found that the reactor designed with lower Ls/H values and higher h1/H,Ds/D values would have smaller power number(Np)values and smaller flow field average velocity.In addition,this study also fitted the correlation equation of Np concerning Reynolds number and h1/H,Ds/D,and Ls/H,and the conclusions of the study can be used as a reference for the design of industrial equipment.展开更多
Nonflammable gel polymer electrolytes(GPEs)are intriguing owing to their flame-retardancy,high ionic conductivity and nonleakage properties.However,their application is critically hindered by unfavorable interfacial c...Nonflammable gel polymer electrolytes(GPEs)are intriguing owing to their flame-retardancy,high ionic conductivity and nonleakage properties.However,their application is critically hindered by unfavorable interfacial compatibility due to the incorporation of high-reactive solvents.Herein,we present an innovative solvent anchoring strategy to remold Li^(+)solvation structure,thus inducing an effective interfacial protective layer to alleviate adverse solvents decomposition.A nonflammable eutectic GPE(DIPE)is synthesized by in situ incorporating poly-ethoxylated trimethylolpropane triacrylate(PETPTA)polymer skeleton to flame-retardant LiTFSI-sulfolane(SL)-based deep eutectic solvent(DES).The “SL solvent anchoring”strategy is validated to rely on dipole-dipole intermolecular interaction between ACH_(2)groups on the PETPTA polymer skeleton and AO@S groups on SL solvents,which breaks the solvation dominance of SL solvents and directly suppresses their decomposition.It simultaneously facilitates reconstruction of a TFSI--dominated Li^(+)solvation sheath without increasing LiTFSI concentration,thereby fostering anion-derived SEI and CEI protective layers.Dynamic interfacial resistance evolution reveals accelerated interfacial Li^(+)transport kinetics in DIPE.Therefore,Li|DIPE|Li cell delivers remarkably enhanced Li reversibility with cycle life over 1000 h at 0.1 mA cm^(-2)and Li|DIPE|LCO cell achieves 90.7%capacity retention over 700 cycles at 0.3 C.This study opens an emerging avenue to remold Li^(+)solvation environment and enhance interfacial compatibility in GPE by manipulating the solvent-anchoring effect.展开更多
Objective:The varying environmental exposure to iodine has long been a topic of interest,particularly given the noticeable increase in the incidence of papillary thyroid carcinoma(PTC)compared to other histopathologic...Objective:The varying environmental exposure to iodine has long been a topic of interest,particularly given the noticeable increase in the incidence of papillary thyroid carcinoma(PTC)compared to other histopathological subtypes globally.This rise in thyroid cancer incidence has been attributed to several factors,including improved detection of early tumors,a higher prevalence of modifiable individual risk factors,and differing exposure to environmental risk factors such as iodine levels.This study aims to explore the epigenetic mechanisms that promote thyroid cancer progression under excess iodine exposure.Materials and methods:This study outlines the following strategy:(i)risk factors were identified through statistical analysis of questionnaire responses in a retrospective iatrogenic study;(ii)following the identification of risk factors,RNA sequencing was performed using tissues from iodine-adequate(IA)and iodine-excess(IE)regions;(iii)candidate hub genes were selected via bioinformatics analysis;(iv)molecular biological techniques were employed to verify the functionality of the key gene.Results:Through careful selection,we focused on SPSB4,a ubiquitin ligase previously unreported in relation to both iodine and thyroid cancer.By optimizing the dosage of PTC cell line activities,we determined how varying iodine levels can either enhance or impair the vitality of thyroid cancer cells.As anticipated,migration and invasion assays revealed significant changes when SPSB4 function was disrupted at the critical dose of KIO3.Conclusion:In terms of epigenetic alterations,SPSB4 emerges as a promising candidate for further investigation,particularly in understanding thyroid cancer progression and potential carcinogenesis.Moreover,E3 ubiquitin ligases,including SPSB4,play a role in orchestrating adipose thermogenesis to maintain body temperature during cold stimuli.This study could also shed light on the influence of iodine on thermogenesis mediated by SPSB4 under cold conditions,while suggesting future exploration of SPSB4's effects on thyroid cancer in colder regions.展开更多
Purpose:This study explores the combined effects of structural and relational embeddedness within alliance networks on firm innovation.By focusing on the interplay between network structures and relationships,this stu...Purpose:This study explores the combined effects of structural and relational embeddedness within alliance networks on firm innovation.By focusing on the interplay between network structures and relationships,this study provides a nonlinear framework to unravel the complex dynamics between alliance networks and firm innovation performance within the manufacturing industry.Design/methodology/approach:Using social network analysis,this study examines the topological structure of firms’alliance networks.An exploratory approach involving K-Means clustering and decision tree methods is employed to identify heterogeneous network types within the alliance networks.The analysis further explores the nonlinear relationships between network characteristics,including closeness centrality,betweenness centrality,clustering coefficient,and relational attributes,including collaboration intensity and breadth,and their combined influence on firm innovation.Findings:The study identified four distinct heterogeneous network types:dyadic,star,ringlike,and complex networks.Each type reveals unique network characteristics and their impact on innovation performance.Key decision rules were extracted,showing that strong relational embeddedness can hinder innovation in dyadic networks,while a greater distance from the central firm correlates with higher innovation performance in star alliance networks.For ringlike alliance networks,moderate cooperation intensity is beneficial for innovation when the clustering coefficient is not high.In complex alliance networks,the combined effects of cooperation intensity,breadth,and clustering coefficient significantly influence innovation.Research limitations:The research presented in this study,while offering valuable insights into the relationship between alliance networks and firm innovation within the manufacturing sector,is subject to several limitations.A focus on the manufacturing industry may restrict the generalizability of our findings to other sectors,where the dynamics of innovation and collaboration might differ significantly.Additionally,our reliance on patent data,while providing a quantifiable measure of innovation,may overlook other forms of innovation that are equally critical in different contexts,such as service innovations or business model transformations.Practical implications:This research offers significant insights into how firms can leverage both network structure and relational aspects to enhance innovation outcomes.By revealing the nonlinear and complex interactions between network embeddedness dimensions,this study makes a valuable contribution to both theory and practice.This highlights that strategic management of both structural and relational embeddedness can foster superior innovation performance,offering firms a competitive advantage by optimizing their alliance network configurations.Originality/value:This study’s originality lies in its examination of the combined effects of structural and relational network embeddings on innovation performance.By identifying distinct network types and their impact on innovation,this study advances the theoretical understanding of how network characteristics interact to shape firm innovation.It contributes to the literature by offering a novel,multidimensional framework that integrates social network theory and resource-based view,providing new insights for firms to leverage their network positions and relationships for competitive advantage.展开更多
Objective:The aim of the present study was to investigate long-term efficacy and safety of percutaneous stent implantation for residual pulmonary artery stenosis(PAS)in pediatric patients after surgical repair of comp...Objective:The aim of the present study was to investigate long-term efficacy and safety of percutaneous stent implantation for residual pulmonary artery stenosis(PAS)in pediatric patients after surgical repair of complicated congenital heart diseases(CHDs).Methods:All pediatric patients diagnosed with residual PAS after surgical repair of complicated CHDs between 1996 and 2020 were retrospectively enrolled in the study.Results:A total of 41 patients(30 males,11 females;median age 5.0 years,median weight 17 kg)were followed-up for a median of 7.1 years.Follow-up echocardiography results demonstrated that the target vessel diameter increased from(3.4±1.1)mm preoperatively to(6.2±1.9)mm one year post-procedure and(6.0±1.5)mm at the final follow-up(p<0.05).The pressure gradient across the stenosis decreased from(52.6±15.8)mmHg preoperatively to(35.8±19.1)mmHg one year post-procedure and(33.1±19.7)mmHg at the final follow-up(p<0.05).Cardiac computed tomography scans indicated that target vessel/distal vessel diameter ratio increased from(0.4±0.2)pre-operatively to(0.8±0.2)one year post-procedure and(0.9±0.3)at the final follow-up(p<0.05).A total of six adverse events were documented,comprising two cases of in-stent restenosis requiring surgical reintervention,three cases of in-stent restenosis managed with regular clinical surveillance,and one case of percutaneous pulmonary valve replacement due to severe pulmonary regurgitation.Kaplan-Meier event-free survival analysis demonstrated that elevated preprocedural right ventricular systolic pressure(>72 mmHg)was significantly associated with long-term adverse events(p=0.024).Conclusion:Percutaneous stent implantation for residual PAS after surgical repair of complicated CHDs effectively relieves vessel stenosis,stabilizes cardiac function,and improves long-term prognosis in pediatric patients.In-stent restenosis remains an unresolved complication,necessitating further advancements in interventional strategies.展开更多
The development of microwave absorption materials(MAMs) is a considerable important topic because our living space is crowed with electromagnetic wave which threatens human’s health.And MAMs are also used in radar st...The development of microwave absorption materials(MAMs) is a considerable important topic because our living space is crowed with electromagnetic wave which threatens human’s health.And MAMs are also used in radar stealth for protecting the weapons from being detected.Many nanomaterials were studied as MAMs,but not all of them have the satisfactory performance.Recently,metal-organic frameworks(MOFs) have attracted tremendous attention owing to their tunable chemical structures,diverse properties,large specific surface area and uniform pore distribution.MOF can transform to porous carbon(PC) which is decorated with metal species at appropriate pyrolysis temperature.However,the loss mechanism of pure MOF-derived PC is often relatively simple.In order to further improve the MA performance,the MOFs coupled with other loss materials are a widely studied method.In this review,we summarize the theories of MA,the progress of different MOF-derived PC-based MAMs,tunable chemical structures incorporated with dielectric loss or magnetic loss materials.The different MA performance and mechanisms are discussed in detail.Finally,the shortcomings,challenges and perspectives of MOF-derived PC-based MAMs are also presented.We hope this review could provide a new insight to design and fabricate MOF-derived PC-based MAMs with better fundamental understanding and practical application.展开更多
Rare earth ion-doped fluorescent glass has become a hotspot due to its characteristics.This work shows that the prepared Dy^3+and Dy^3+/Eu^3+doped glasses have white light emission under ultraviolet excitation.There i...Rare earth ion-doped fluorescent glass has become a hotspot due to its characteristics.This work shows that the prepared Dy^3+and Dy^3+/Eu^3+doped glasses have white light emission under ultraviolet excitation.There is a higher yellow light/blue light(Y/B)value,indicating an increase in the covalentity of Dy-O,and decrease in the symmetry with the increasing concentration of dopants(Dy^3+).The correlated color temperature(CCT)can be effectively reduced by the red light emission of Eu^3+,and the order of influence of excitation wavelength on CCT is 395 nm>382 nm>365 nm.The delay curve demonstrates the energy transfer from Dy^3+to Eu^3+.The glass has the characteristics of anti-blue light damage and wide tunable color temperature,which illustrates that it has potential application in the field of white LED.展开更多
The air-cycle refrigeration system is widely used in commercial and military aircraft,and its efficiency greatly affects aircraft performance.Nowadays,this system requires a more efficient design and optimization meth...The air-cycle refrigeration system is widely used in commercial and military aircraft,and its efficiency greatly affects aircraft performance.Nowadays,this system requires a more efficient design and optimization method.In this paper,a short-cut optimization method with high efficiency and effectiveness is introduced for both conventional and electric air-cycle refrigeration systems.Based on the system characteristics,a four-layer parameter matching algorithm is designed which avoids computational difficulty caused by simultaneous equations.Fuel penalty is chosen as the objective function of optimization;design variables are reduced based on sensitivity analysis to improve optimization efficiency.The results show that the 3-variable optimization of the conventional air-cycle refrigeration system can obtain almost the same results as the traditional 6-variable optimization in that these two optimizations can both significantly reduce the fuel penalty.However,the computer running time of the 3-variable optimization is much shorter than that of the 6-variable optimization.The optimal fuel penalty of the electric air-cycle refrigeration system is lower than that of the conventional one.This study can provide reference for optimizing the aircycle refrigeration system of aircraft.展开更多
Unmanned Aerial Vehicle(UAV)swarm has become the inevitable trend of development,which will enjoy broad prospects to be applied in the future.However,the change of UAV application mode will certainly bring new technic...Unmanned Aerial Vehicle(UAV)swarm has become the inevitable trend of development,which will enjoy broad prospects to be applied in the future.However,the change of UAV application mode will certainly bring new technical challenges in the flight management,environmental perception,collaborative control as well as other fields.This paper considers that it can be an effective solution to realize the unified management of spatial information on the UAV platform by adopting the spatial grid model represented by the Geo SOT-3D,and to reduce the workload of flight management,airborne environmental perception,and ranging in the neighborhood through the association and query of all spatial grid data.展开更多
In order to understand the crustal structure and tectonic background of the Changning–Gongxiang area, southeastern Sichuan Province, where a series of moderate-to-strong earthquakes occurred in recent years, we utili...In order to understand the crustal structure and tectonic background of the Changning–Gongxiang area, southeastern Sichuan Province, where a series of moderate-to-strong earthquakes occurred in recent years, we utilized the seismic phase data both from a local dense array and from the regional seismic networks;we used the tomoDD program to invert for the high-resolution three-dimensional velocity structure within the depth range of 0–10 km and for accurate hypocentral locations in this area. We analyzed the seismogenic structures for the events of Xingwen M5.7 in 2018 and Gongxian M5.3 and Changning M6.0 in 2019. The results show that:(1) widespread lateral inhomogeneity exists in the velocity structure of the study area, and the location of the velocity anomaly is largely consistent with known structures. In the range of distinguishable depth, the inhomogeneity decreases with increasing depth, and the velocity structure anomalies in some areas are continuous in depth;(2) earthquakes occurred in clusters, showing the characteristics of zonal folding trends in the NW-SE and NE-SW directions;the focal depth in the area is generally shallow in both the sedimentary cap and the crystalline basement. The seismogenic structures of small earthquake clusters are different in size and occurrence in different sections, and the clusters occurred mostly in regions with high P-or S-wave velocities;(3) synthesis of a variety of data suggests that the seismogenic structures of the Xingwen M5.7 and Changning M6.0 earthquakes are associated with slip faults that trend NW-SE in, respectively, the south wing and the axis of the Changning–Shuanghe anticline, while that of the Gongxian M5.3 earthquake is associated with thrust faults that trend N-S in the Jianwu syncline region. The dynamic sources of the three earthquakes are all from the SE pushing of the Qinghai–Tibet block on the Sichuan basin;(4) the risk of future strong earthquakes in this area must be reevaluated in light of the facts(a)that in recent years, moderate-to-strong earthquake swarms have occurred frequently in southeast Sichuan;(b) that the complex structural area exhibits the easy-to-trigger characteristic, and(c) that the small-scale faults in this area are characterized by the phenomenon of stress "lock and release".展开更多
This paper presents a new analytical solution for assessing the longitudinal deformation of shield tunnel associated with overcrossing tunnelling in consideration of circumferential joints.A simplified longitudinal be...This paper presents a new analytical solution for assessing the longitudinal deformation of shield tunnel associated with overcrossing tunnelling in consideration of circumferential joints.A simplified longitudinal beam-spring model(SLBSM)is established to model the longitudinal behaviours of shield tunnel,which can consider the opening and dislocation between segmental rings simultaneously.Then,the existing tunnel is treated as the SLBSM resting on the elastic foundation.The state equations including tunnel displacements and internal forces are constructed to solve the discontinuous deformation of circumferential joint-segmental ring.The feasibility of the proposed solution is verified through three well-documented cases.The predictions from the proposed method are also compared with other analytical methods.It is found that the proposed method can well capture the deformation of tunnel segmental rings and joints,where the rigid displacement mainly occurs in the segmental rings while the rotation and dislocation occur in the circumferential joints.Some dominant parameters are also analysed to explore the effects on existing tunnel deformation,including the rotation stiffness and shearing stiffness of joints,the skew angle and the clearance between new and old tunnels.展开更多
Focal mechanism solutions and centroid depths of 312 M≥4 aftershocks from the 2008 Wenchuan earthquake sequence have been derived by CAP （Cut and Paste） method from broadband waveform data with relatively high sign...Focal mechanism solutions and centroid depths of 312 M≥4 aftershocks from the 2008 Wenchuan earthquake sequence have been derived by CAP （Cut and Paste） method from broadband waveform data with relatively high signal-to-noise ratio （SNR）. Following this, we have analyzed the distribution of focal depths and the stress tensors, as well as the types of focal mechanisms. The major results are： （1） different cross-sections show that the depth ranges of the aftershocks at the southern and northern ends of the aftershock area along the Longmenshan fault zone are wider than those on the central segment, where rare M≥4 aftershocks occurred at depths shallower than 10 kin. The main faults trend to the NW on the southern and central segments, and for the northern segment, no dominant trend direction has been determined; （2） stress tensor distribution demonstrates that the majority of the aftershock areas on the cross-section along the major axis are mainly under compressive stress perpendicular to the profile; however, for the areas near Lixian, Beichuan, Qingchuan and the shallow parts of its northern segment, large principal stress components are parallel to the major axis profile direction. On the cross-sections perpendicular to the major axis, the three areas above can be divided into two parts： one with dominantly compressional stress near the major faults of the Longmenshan fault zone on the SE side, and the other with NE-direction push along the fault zone on the NW side; （3） the stress tensor distribution in map view is very similar to those on the vertical cross-sections. In map view, the orientation of the principal compressional stress axis $1 on the central segment of the aftershock area presents an SE-trending arc shape; （4） the stress tensor slices at different depths show that the orientation of S1 axis mainly changes on the central segment and at the northern end, indicating that the two segments have different seismogenic structures at different depths; （5） with the exception of the northern end of the aftershock region, the orientation of the $1 axis changes little during the early and late stages, illustrating the seismogenic structures are relatively stable; （6） preliminary analyses for the seismogenic structures at the northern end indicated that deeper strike-slip quakes occurred on the ENE-striking branch at first, and then the NNE-striking branch faults at the northern end were activated and generated a series of relatively shallow strike-slip earthquakes due to subsequent stress-triggering; （7） the aftershock triggering mechanism that occurred near Lixian is different between the shallow and deep depths, and between the early and late stages, indicating that the main faults and the branch faults responsible for aftershocks are at different depths. Consequently, the relaxation effect of the main shock particularIy impacts the branch faults.展开更多
The seismicity of Longrnenshan fault zone and its vicinities before the 12 May 2008 Wenchuan Ms8.0 earthquake is studied. Based on the digital seismic waveform data observed from regional seismic networks and mobile s...The seismicity of Longrnenshan fault zone and its vicinities before the 12 May 2008 Wenchuan Ms8.0 earthquake is studied. Based on the digital seismic waveform data observed from regional seismic networks and mobile stations, the focal mechanism solutions are determined. Our analysis results show that the seismicities of Longmenshan fault zone before the 12 May 2008 Wenchuan earthquake were in stable state. No obvious phenomena of seismic activity intensifying appeared. According to focal mechanism solutions of some small earthquakes before the 12 May 2008 Wenchuan earthquake, the direction of principal compressive stress P-axis is WNW-ESE. The two hypocenter fault planes are NE-striking and NW-striking. The plane of NE direction is among N50°-70°E, the dip angles of fault planes are 60°-70° and it is very steep. The faultings of most earthquakes are dominantly characterized by dip-slip reverse and small part of faultings present strike-slip. The azimuths of principal compressive stress, the strikes of source fault planes and the dislocation types calculated from some small earthquakes before the 12 May 2008 Wenchuan earthquake are in accordance with that of the main shock. The average stress field of micro-rupture along the Longmenshan fault zone before the great earthquake is also consistent with that calculated from main shock. Zipingpu dam is located in the east side 20 km from the initial rupture area of the 12 May 2008 Wenchuan earthquake. The activity increment of small earthquakes in the Zipingpu dam is in the period of water discharging. The source parameter results of the small earthquakes which occurred near the initial rupture area of the 12 May 2008 Wenchuan earthquake indicate that the focal depths are 5 to 14 km and the source parameters are identical with that of earthquake.展开更多
This paper proposes a trust ant colony routing algorithm by introducing a node trust evaluation model based on the D-S evidence theory into the ant colony routing protocol to improve the security of wireless sensor ne...This paper proposes a trust ant colony routing algorithm by introducing a node trust evaluation model based on the D-S evidence theory into the ant colony routing protocol to improve the security of wireless sensor networks. To reduce the influence of conflict evidences caused by malicious nods, the consistent intensity is introduced to preprocess conflict evidences before using the D-S combination rule to improve the reliability of the D-S based trust evaluation. The nodes with high trust values will be selected as the routing nodes to insure the routing security, and the trust values are used as heuristic functions of the ant colony routing algorithm. The simulation tests are conducted by using the network simulator NS2 to observe the outcomes of performance metrics of packets loss rate and average end-to-end delay etc. to indirectly evaluate the security issue under the attack of inside malicious nodes. The simulation results show that the proposed trust routing algorithm can efficiently resist malicious attacks in terms of keeping performances of the average end-to-end delay, the throughtput and the routing packet overhead under attacking from malicious nodes.展开更多
Selenium,an element belonging to the same group in the periodic table as sulfur,has a high electronic conductivity(1×10^(-5)S/cm)and a high volumetric energy density(3253 mA h/cm^(3)),which is a prospective catho...Selenium,an element belonging to the same group in the periodic table as sulfur,has a high electronic conductivity(1×10^(-5)S/cm)and a high volumetric energy density(3253 mA h/cm^(3)),which is a prospective cathode material for high-energy all-solid-state rechargeable batteries.However,its wide use is hindered by large volume expansion and low utilization rate.In this work,Se-infused nitrogen-doped hierarchical meso-microporous carbon composites(Se/NHPC)are prepared by a melt-diffusion process.Amorphous Se is uniformly dispersed in meso-micropores of NHPC with a high mass loading of 81%.All-solid-state Li-Se batteries fabricated by using Se/NHPC as the cathode,a Li-In alloy as the anode,and Li_(6)PS_(5)Cl as the solid-state electrolyte,deliver a highly reversible capacity of 621 m Ah/g(92%of theoretical capacity),a good rate capability and a high capacity retention value of 80.9%after 100 cycles.It is found that the capacity decay of Se cathode is mainly related to the interfacial degradation and the separation of Se from the carbon substrate,as suggested by the continuous increase of interfacial resistance and the structural transformation from amorphous Senchains to Se8rings initial discharge/charge cycle and then to the trigonally crystalline Se chains structure after the long-term cycles.展开更多
基金funded by the National Key Research and Development Program of China(Grant No.2024YFE0209000)the NSFC(Grant No.U23B2019).
文摘Graph Neural Networks(GNNs)have proven highly effective for graph classification across diverse fields such as social networks,bioinformatics,and finance,due to their capability to learn complex graph structures.However,despite their success,GNNs remain vulnerable to adversarial attacks that can significantly degrade their classification accuracy.Existing adversarial attack strategies primarily rely on label information to guide the attacks,which limits their applicability in scenarios where such information is scarce or unavailable.This paper introduces an innovative unsupervised attack method for graph classification,which operates without relying on label information,thereby enhancing its applicability in a broad range of scenarios.Specifically,our method first leverages a graph contrastive learning loss to learn high-quality graph embeddings by comparing different stochastic augmented views of the graphs.To effectively perturb the graphs,we then introduce an implicit estimator that measures the impact of various modifications on graph structures.The proposed strategy identifies and flips edges with the top-K highest scores,determined by the estimator,to maximize the degradation of the model’s performance.In addition,to defend against such attack,we propose a lightweight regularization-based defense mechanism that is specifically tailored to mitigate the structural perturbations introduced by our attack strategy.It enhances model robustness by enforcing embedding consistency and edge-level smoothness during training.We conduct experiments on six public TU graph classification datasets:NCI1,NCI109,Mutagenicity,ENZYMES,COLLAB,and DBLP_v1,to evaluate the effectiveness of our attack and defense strategies.Under an attack budget of 3,the maximum reduction in model accuracy reaches 6.67%on the Graph Convolutional Network(GCN)and 11.67%on the Graph Attention Network(GAT)across different datasets,indicating that our unsupervised method induces degradation comparable to state-of-the-art supervised attacks.Meanwhile,our defense achieves the highest accuracy recovery of 3.89%(GCN)and 5.00%(GAT),demonstrating improved robustness against structural perturbations.
基金supported by the National Natural Science Foundation of China(Nos.52172214,52272221,52171182)the Postdoctoral Innovation Project of Shandong Province(No.202102003)+2 种基金The Key Research and Development Program of Shandong Province(2021ZLGX01)the Qilu Young Scholar ProgramHPC Cloud Platform of Shandong University are also thanked.
文摘The risk of flammability is an unavoidable issue for gel polymer electrolytes(GPEs).Usually,flameretardant solvents are necessary to be used,but most of them would react with anode/cathode easily and cause serious interfacial instability,which is a big challenge for design and application of nonflammable GPEs.Here,a nonflammable GPE(SGPE)is developed by in situ polymerizing trifluoroethyl methacrylate(TFMA)monomers with flame-retardant triethyl phosphate(TEP)solvents and LiTFSI–LiDFOB dual lithium salts.TEP is strongly anchored to PTFMA matrix via polarity interaction between-P=O and-CH_(2)CF_(3).It reduces free TEP molecules,which obviously mitigates interfacial reactions,and enhances flame-retardant performance of TEP surprisingly.Anchored TEP molecules are also inhibited in solvation of Li^(+),leading to anion-dominated solvation sheath,which creates inorganic-rich solid electrolyte interface/cathode electrolyte interface layers.Such coordination structure changes Li^(+)transport from sluggish vehicular to fast structural transport,raising ionic conductivity to 1.03 mS cm^(-1) and transfer number to 0.41 at 30℃.The Li|SGPE|Li cell presents highly reversible Li stripping/plating performance for over 1000 h at 0.1 mA cm^(−2),and 4.2 V LiCoO_(2)|SGPE|Li battery delivers high average specific capacity>120 mAh g^(−1) over 200 cycles.This study paves a new way to make nonflammable GPE that is compatible with Li metal anode.
基金funded by the National Key Research and Development Project,grant number 2021YFE0192100Natural Science Foundation of Hunan Province,grant numbers 2021JJ30694,2023JJ30529+4 种基金Innovation and Entrepreneurship Training Program for College Students in Hunan Province,grant number S202210555254Key Projects of Hunan Provincial Education Department,grant number 21A0285Natural Science Foundation of Hunan Provincial and Municipal Co-Funding,grant number 2022JJ50029Key Projects of Shaoyang Science and Technology Bureau,grant number 2021GZ031Innovation and Entrepreneurship Training Program for College Students of the University of South China,grant numbers D202405212006326156,D202405210948392932,D202405211329047648,D202405221955420827.
文摘One of the most prevalent malignant tumors worldwide,stomach cancer still has a high incidence and fatality rate in China,and the number of young people developing early-onset gastric cancer is steadily increasing.The 5-year survival rate of stomach cancer is typically 30%–35%,the prognosis is bad,the patients’quality of life is low,and the progression of advanced gastric cancer cannot be effectively managed despite the use of surgical surgery,chemotherapy,and other medicines.We urgently need molecular biomarkers with high specificity and sensitivity to increase the early gastric cancer detection rate,extend patient survival,and improve patient quality of life.The initial diagnosis of gastric cancer primarily depends on gastroscopy and biopsy,and invasive procedures cause significant discomfort to patients.Similar to this,treating advanced and metastatic stomach cancer is a pressing issue that requires attention.More and more immune checkpoint molecules have been discovered,and corresponding inhibitors are gradually being applied to clinical diagnosis and treatment.Recently,some non-coding RNAs have begun to be used as new targets for the treatment of gastric cancer.Some non-coding RNAs are highly present in the serum or urine of gastric cancer patients and can be used as diagnostic markers or prognostic indicators.Many clinical trials targeting non-coding RNAs have also shown good therapeutic effects.In general,targeting non-coding RNAs has shown good therapeutic effects.The biomarkers for gastric cancer detection and treatment are reviewed in this article,focusing on the new non-coding RNAs used in diagnosis,prognosis,and treatment.Patients with stomach cancer should have access to more precise and efficient diagnosis and treatment choices as a result of ongoing technological advancements and thorough research.
基金supported by the National Natural Science Foundation of China(52361145714,21673252)the Beijing Municipal Education Commission(2019821001)+1 种基金Climbing Program Foundation from Beijing Institute of Petrochemical Technology(BIPTAAl-2021007)the ZhiYuan Fund key Project from Beijing Institute of Petrochemical Technology(2024003).
文摘KanCell is a deep learning model based on Kolmogorov-Arnold networks(KAN)designed to enhance cellular heterogeneity analysis by integrating single-cell RNA sequencing and spatial transcriptomics(ST)data.ST technologies provide insights into gene expression within tissue context,revealing cellular interactions and microenvironments.To fully leverage this potential,effective computational models are crucial.We evaluate KanCell on both simulated and real datasets from technologies such as STARmap,Slide-seq,Visium,and Spatial Transcriptomics.Our results demonstrate that KanCell outperforms existing methods across metrics like PCC,SSIM,COSSIM,RMSE,JSD,ARS,and ROC,with robust performance under varying cell numbers and background noise.Real-world applications on human lymph nodes,hearts,melanoma,breast cancer,dorsolateral prefrontal cortex,and mouse embryo brains confirmed its reliability.Compared with traditional approaches,KanCell effectively captures non-linear relationships and optimizes computational efficiency through KAN,providing an accurate and efficient tool for ST.By improving data accuracy and resolving cell type composition,KanCell reveals cellular heterogeneity,clarifies disease microenvironments,and identifies therapeutic targets,addressing complex biological challenges.
基金supported by the Natural Science Foundation of Shandong Province(ZR2023ZD22)the Major Research and Development Program of Shandong Province(2023CXGC010601).
文摘Under the dual-carbon background,the technological updating of traditional high-energy-consuming equipment should not be delayed,and the problem of reactor energy consumption should not be ignored.Therefore,this study is based on computational fluid dynamics(CFD)theory to simulate the spiral stirred reactor with different design parameters(distance of paddle from bottom surface to reactor height ratio h1/H,diameter of stirring paddle to reactor diameter ratio Ds/D,length of blade section to reactor height ratio Ls/H).It was found that the reactor designed with lower Ls/H values and higher h1/H,Ds/D values would have smaller power number(Np)values and smaller flow field average velocity.In addition,this study also fitted the correlation equation of Np concerning Reynolds number and h1/H,Ds/D,and Ls/H,and the conclusions of the study can be used as a reference for the design of industrial equipment.
基金supported by the National Natural Science Foundation of China(52172214,52472220,52272221,52171182)Postdoctoral Innovation Project of Shandong Province(202102003)+2 种基金The“New 20 Clauses about Colleges and Universities”Program of Jinan(202228107)the Qilu Young Scholar Programthe HPC Cloud Platform of Shandong University are also acknowledged。
文摘Nonflammable gel polymer electrolytes(GPEs)are intriguing owing to their flame-retardancy,high ionic conductivity and nonleakage properties.However,their application is critically hindered by unfavorable interfacial compatibility due to the incorporation of high-reactive solvents.Herein,we present an innovative solvent anchoring strategy to remold Li^(+)solvation structure,thus inducing an effective interfacial protective layer to alleviate adverse solvents decomposition.A nonflammable eutectic GPE(DIPE)is synthesized by in situ incorporating poly-ethoxylated trimethylolpropane triacrylate(PETPTA)polymer skeleton to flame-retardant LiTFSI-sulfolane(SL)-based deep eutectic solvent(DES).The “SL solvent anchoring”strategy is validated to rely on dipole-dipole intermolecular interaction between ACH_(2)groups on the PETPTA polymer skeleton and AO@S groups on SL solvents,which breaks the solvation dominance of SL solvents and directly suppresses their decomposition.It simultaneously facilitates reconstruction of a TFSI--dominated Li^(+)solvation sheath without increasing LiTFSI concentration,thereby fostering anion-derived SEI and CEI protective layers.Dynamic interfacial resistance evolution reveals accelerated interfacial Li^(+)transport kinetics in DIPE.Therefore,Li|DIPE|Li cell delivers remarkably enhanced Li reversibility with cycle life over 1000 h at 0.1 mA cm^(-2)and Li|DIPE|LCO cell achieves 90.7%capacity retention over 700 cycles at 0.3 C.This study opens an emerging avenue to remold Li^(+)solvation environment and enhance interfacial compatibility in GPE by manipulating the solvent-anchoring effect.
基金supported by National Natural Science Foundation of China(8183000355)。
文摘Objective:The varying environmental exposure to iodine has long been a topic of interest,particularly given the noticeable increase in the incidence of papillary thyroid carcinoma(PTC)compared to other histopathological subtypes globally.This rise in thyroid cancer incidence has been attributed to several factors,including improved detection of early tumors,a higher prevalence of modifiable individual risk factors,and differing exposure to environmental risk factors such as iodine levels.This study aims to explore the epigenetic mechanisms that promote thyroid cancer progression under excess iodine exposure.Materials and methods:This study outlines the following strategy:(i)risk factors were identified through statistical analysis of questionnaire responses in a retrospective iatrogenic study;(ii)following the identification of risk factors,RNA sequencing was performed using tissues from iodine-adequate(IA)and iodine-excess(IE)regions;(iii)candidate hub genes were selected via bioinformatics analysis;(iv)molecular biological techniques were employed to verify the functionality of the key gene.Results:Through careful selection,we focused on SPSB4,a ubiquitin ligase previously unreported in relation to both iodine and thyroid cancer.By optimizing the dosage of PTC cell line activities,we determined how varying iodine levels can either enhance or impair the vitality of thyroid cancer cells.As anticipated,migration and invasion assays revealed significant changes when SPSB4 function was disrupted at the critical dose of KIO3.Conclusion:In terms of epigenetic alterations,SPSB4 emerges as a promising candidate for further investigation,particularly in understanding thyroid cancer progression and potential carcinogenesis.Moreover,E3 ubiquitin ligases,including SPSB4,play a role in orchestrating adipose thermogenesis to maintain body temperature during cold stimuli.This study could also shed light on the influence of iodine on thermogenesis mediated by SPSB4 under cold conditions,while suggesting future exploration of SPSB4's effects on thyroid cancer in colder regions.
基金supported by the National Social Science Fund of China(No.22FGLB035)Fujian Provincial Federation of Social Sciences(No.FJ2023B109).
文摘Purpose:This study explores the combined effects of structural and relational embeddedness within alliance networks on firm innovation.By focusing on the interplay between network structures and relationships,this study provides a nonlinear framework to unravel the complex dynamics between alliance networks and firm innovation performance within the manufacturing industry.Design/methodology/approach:Using social network analysis,this study examines the topological structure of firms’alliance networks.An exploratory approach involving K-Means clustering and decision tree methods is employed to identify heterogeneous network types within the alliance networks.The analysis further explores the nonlinear relationships between network characteristics,including closeness centrality,betweenness centrality,clustering coefficient,and relational attributes,including collaboration intensity and breadth,and their combined influence on firm innovation.Findings:The study identified four distinct heterogeneous network types:dyadic,star,ringlike,and complex networks.Each type reveals unique network characteristics and their impact on innovation performance.Key decision rules were extracted,showing that strong relational embeddedness can hinder innovation in dyadic networks,while a greater distance from the central firm correlates with higher innovation performance in star alliance networks.For ringlike alliance networks,moderate cooperation intensity is beneficial for innovation when the clustering coefficient is not high.In complex alliance networks,the combined effects of cooperation intensity,breadth,and clustering coefficient significantly influence innovation.Research limitations:The research presented in this study,while offering valuable insights into the relationship between alliance networks and firm innovation within the manufacturing sector,is subject to several limitations.A focus on the manufacturing industry may restrict the generalizability of our findings to other sectors,where the dynamics of innovation and collaboration might differ significantly.Additionally,our reliance on patent data,while providing a quantifiable measure of innovation,may overlook other forms of innovation that are equally critical in different contexts,such as service innovations or business model transformations.Practical implications:This research offers significant insights into how firms can leverage both network structure and relational aspects to enhance innovation outcomes.By revealing the nonlinear and complex interactions between network embeddedness dimensions,this study makes a valuable contribution to both theory and practice.This highlights that strategic management of both structural and relational embeddedness can foster superior innovation performance,offering firms a competitive advantage by optimizing their alliance network configurations.Originality/value:This study’s originality lies in its examination of the combined effects of structural and relational network embeddings on innovation performance.By identifying distinct network types and their impact on innovation,this study advances the theoretical understanding of how network characteristics interact to shape firm innovation.It contributes to the literature by offering a novel,multidimensional framework that integrates social network theory and resource-based view,providing new insights for firms to leverage their network positions and relationships for competitive advantage.
基金approved by the Institutional Review Board of Guangdong Provincial People's Hospital(KY-Q-2022-336-03).
文摘Objective:The aim of the present study was to investigate long-term efficacy and safety of percutaneous stent implantation for residual pulmonary artery stenosis(PAS)in pediatric patients after surgical repair of complicated congenital heart diseases(CHDs).Methods:All pediatric patients diagnosed with residual PAS after surgical repair of complicated CHDs between 1996 and 2020 were retrospectively enrolled in the study.Results:A total of 41 patients(30 males,11 females;median age 5.0 years,median weight 17 kg)were followed-up for a median of 7.1 years.Follow-up echocardiography results demonstrated that the target vessel diameter increased from(3.4±1.1)mm preoperatively to(6.2±1.9)mm one year post-procedure and(6.0±1.5)mm at the final follow-up(p<0.05).The pressure gradient across the stenosis decreased from(52.6±15.8)mmHg preoperatively to(35.8±19.1)mmHg one year post-procedure and(33.1±19.7)mmHg at the final follow-up(p<0.05).Cardiac computed tomography scans indicated that target vessel/distal vessel diameter ratio increased from(0.4±0.2)pre-operatively to(0.8±0.2)one year post-procedure and(0.9±0.3)at the final follow-up(p<0.05).A total of six adverse events were documented,comprising two cases of in-stent restenosis requiring surgical reintervention,three cases of in-stent restenosis managed with regular clinical surveillance,and one case of percutaneous pulmonary valve replacement due to severe pulmonary regurgitation.Kaplan-Meier event-free survival analysis demonstrated that elevated preprocedural right ventricular systolic pressure(>72 mmHg)was significantly associated with long-term adverse events(p=0.024).Conclusion:Percutaneous stent implantation for residual PAS after surgical repair of complicated CHDs effectively relieves vessel stenosis,stabilizes cardiac function,and improves long-term prognosis in pediatric patients.In-stent restenosis remains an unresolved complication,necessitating further advancements in interventional strategies.
基金financial support from Ministry of Science and Technology of China(MoST,2016YFA0200200)the National Natural Science Foundation of China(NSFC,21875114,51373078,and 51422304)NSF of Tianjin City(15JCYBJC17700)。
文摘The development of microwave absorption materials(MAMs) is a considerable important topic because our living space is crowed with electromagnetic wave which threatens human’s health.And MAMs are also used in radar stealth for protecting the weapons from being detected.Many nanomaterials were studied as MAMs,but not all of them have the satisfactory performance.Recently,metal-organic frameworks(MOFs) have attracted tremendous attention owing to their tunable chemical structures,diverse properties,large specific surface area and uniform pore distribution.MOF can transform to porous carbon(PC) which is decorated with metal species at appropriate pyrolysis temperature.However,the loss mechanism of pure MOF-derived PC is often relatively simple.In order to further improve the MA performance,the MOFs coupled with other loss materials are a widely studied method.In this review,we summarize the theories of MA,the progress of different MOF-derived PC-based MAMs,tunable chemical structures incorporated with dielectric loss or magnetic loss materials.The different MA performance and mechanisms are discussed in detail.Finally,the shortcomings,challenges and perspectives of MOF-derived PC-based MAMs are also presented.We hope this review could provide a new insight to design and fabricate MOF-derived PC-based MAMs with better fundamental understanding and practical application.
基金Project supported by Science and Technology Department of Jilin Province of China(20190302006GX)Technology Innovation Fund of Changchun University of Science and Technology(XJJLG-2017-06,XJJLG-2018-10)。
文摘Rare earth ion-doped fluorescent glass has become a hotspot due to its characteristics.This work shows that the prepared Dy^3+and Dy^3+/Eu^3+doped glasses have white light emission under ultraviolet excitation.There is a higher yellow light/blue light(Y/B)value,indicating an increase in the covalentity of Dy-O,and decrease in the symmetry with the increasing concentration of dopants(Dy^3+).The correlated color temperature(CCT)can be effectively reduced by the red light emission of Eu^3+,and the order of influence of excitation wavelength on CCT is 395 nm>382 nm>365 nm.The delay curve demonstrates the energy transfer from Dy^3+to Eu^3+.The glass has the characteristics of anti-blue light damage and wide tunable color temperature,which illustrates that it has potential application in the field of white LED.
基金the financial supports from Pre-research Project of National Defense FoundationNational Natural Science Foundation of China(No.51706232)。
文摘The air-cycle refrigeration system is widely used in commercial and military aircraft,and its efficiency greatly affects aircraft performance.Nowadays,this system requires a more efficient design and optimization method.In this paper,a short-cut optimization method with high efficiency and effectiveness is introduced for both conventional and electric air-cycle refrigeration systems.Based on the system characteristics,a four-layer parameter matching algorithm is designed which avoids computational difficulty caused by simultaneous equations.Fuel penalty is chosen as the objective function of optimization;design variables are reduced based on sensitivity analysis to improve optimization efficiency.The results show that the 3-variable optimization of the conventional air-cycle refrigeration system can obtain almost the same results as the traditional 6-variable optimization in that these two optimizations can both significantly reduce the fuel penalty.However,the computer running time of the 3-variable optimization is much shorter than that of the 6-variable optimization.The optimal fuel penalty of the electric air-cycle refrigeration system is lower than that of the conventional one.This study can provide reference for optimizing the aircycle refrigeration system of aircraft.
文摘Unmanned Aerial Vehicle(UAV)swarm has become the inevitable trend of development,which will enjoy broad prospects to be applied in the future.However,the change of UAV application mode will certainly bring new technical challenges in the flight management,environmental perception,collaborative control as well as other fields.This paper considers that it can be an effective solution to realize the unified management of spatial information on the UAV platform by adopting the spatial grid model represented by the Geo SOT-3D,and to reduce the workload of flight management,airborne environmental perception,and ranging in the neighborhood through the association and query of all spatial grid data.
基金supported by National Natural Science Foundation of China (No. 41574047)Sichuan–Yunnan national earthquake monitoring and prediction experimental field project (2016CESE0101, 2018CSES0209)Project of Science for Earthquake Resilience (XH202302)
文摘In order to understand the crustal structure and tectonic background of the Changning–Gongxiang area, southeastern Sichuan Province, where a series of moderate-to-strong earthquakes occurred in recent years, we utilized the seismic phase data both from a local dense array and from the regional seismic networks;we used the tomoDD program to invert for the high-resolution three-dimensional velocity structure within the depth range of 0–10 km and for accurate hypocentral locations in this area. We analyzed the seismogenic structures for the events of Xingwen M5.7 in 2018 and Gongxian M5.3 and Changning M6.0 in 2019. The results show that:(1) widespread lateral inhomogeneity exists in the velocity structure of the study area, and the location of the velocity anomaly is largely consistent with known structures. In the range of distinguishable depth, the inhomogeneity decreases with increasing depth, and the velocity structure anomalies in some areas are continuous in depth;(2) earthquakes occurred in clusters, showing the characteristics of zonal folding trends in the NW-SE and NE-SW directions;the focal depth in the area is generally shallow in both the sedimentary cap and the crystalline basement. The seismogenic structures of small earthquake clusters are different in size and occurrence in different sections, and the clusters occurred mostly in regions with high P-or S-wave velocities;(3) synthesis of a variety of data suggests that the seismogenic structures of the Xingwen M5.7 and Changning M6.0 earthquakes are associated with slip faults that trend NW-SE in, respectively, the south wing and the axis of the Changning–Shuanghe anticline, while that of the Gongxian M5.3 earthquake is associated with thrust faults that trend N-S in the Jianwu syncline region. The dynamic sources of the three earthquakes are all from the SE pushing of the Qinghai–Tibet block on the Sichuan basin;(4) the risk of future strong earthquakes in this area must be reevaluated in light of the facts(a)that in recent years, moderate-to-strong earthquake swarms have occurred frequently in southeast Sichuan;(b) that the complex structural area exhibits the easy-to-trigger characteristic, and(c) that the small-scale faults in this area are characterized by the phenomenon of stress "lock and release".
文摘This paper presents a new analytical solution for assessing the longitudinal deformation of shield tunnel associated with overcrossing tunnelling in consideration of circumferential joints.A simplified longitudinal beam-spring model(SLBSM)is established to model the longitudinal behaviours of shield tunnel,which can consider the opening and dislocation between segmental rings simultaneously.Then,the existing tunnel is treated as the SLBSM resting on the elastic foundation.The state equations including tunnel displacements and internal forces are constructed to solve the discontinuous deformation of circumferential joint-segmental ring.The feasibility of the proposed solution is verified through three well-documented cases.The predictions from the proposed method are also compared with other analytical methods.It is found that the proposed method can well capture the deformation of tunnel segmental rings and joints,where the rigid displacement mainly occurs in the segmental rings while the rotation and dislocation occur in the circumferential joints.Some dominant parameters are also analysed to explore the effects on existing tunnel deformation,including the rotation stiffness and shearing stiffness of joints,the skew angle and the clearance between new and old tunnels.
基金supported by the projects from Ministry of National Science and Technology of China(Grant No. 2012BAK19B01-01)National Basic Research Program of China (Grant No. 2008CB425701)
文摘Focal mechanism solutions and centroid depths of 312 M≥4 aftershocks from the 2008 Wenchuan earthquake sequence have been derived by CAP （Cut and Paste） method from broadband waveform data with relatively high signal-to-noise ratio （SNR）. Following this, we have analyzed the distribution of focal depths and the stress tensors, as well as the types of focal mechanisms. The major results are： （1） different cross-sections show that the depth ranges of the aftershocks at the southern and northern ends of the aftershock area along the Longmenshan fault zone are wider than those on the central segment, where rare M≥4 aftershocks occurred at depths shallower than 10 kin. The main faults trend to the NW on the southern and central segments, and for the northern segment, no dominant trend direction has been determined; （2） stress tensor distribution demonstrates that the majority of the aftershock areas on the cross-section along the major axis are mainly under compressive stress perpendicular to the profile; however, for the areas near Lixian, Beichuan, Qingchuan and the shallow parts of its northern segment, large principal stress components are parallel to the major axis profile direction. On the cross-sections perpendicular to the major axis, the three areas above can be divided into two parts： one with dominantly compressional stress near the major faults of the Longmenshan fault zone on the SE side, and the other with NE-direction push along the fault zone on the NW side; （3） the stress tensor distribution in map view is very similar to those on the vertical cross-sections. In map view, the orientation of the principal compressional stress axis $1 on the central segment of the aftershock area presents an SE-trending arc shape; （4） the stress tensor slices at different depths show that the orientation of S1 axis mainly changes on the central segment and at the northern end, indicating that the two segments have different seismogenic structures at different depths; （5） with the exception of the northern end of the aftershock region, the orientation of the $1 axis changes little during the early and late stages, illustrating the seismogenic structures are relatively stable; （6） preliminary analyses for the seismogenic structures at the northern end indicated that deeper strike-slip quakes occurred on the ENE-striking branch at first, and then the NNE-striking branch faults at the northern end were activated and generated a series of relatively shallow strike-slip earthquakes due to subsequent stress-triggering; （7） the aftershock triggering mechanism that occurred near Lixian is different between the shallow and deep depths, and between the early and late stages, indicating that the main faults and the branch faults responsible for aftershocks are at different depths. Consequently, the relaxation effect of the main shock particularIy impacts the branch faults.
基金supported by National Key Basic Research 973bNational Scientific technology support plan (2006BAC01B02-01-01).
文摘The seismicity of Longrnenshan fault zone and its vicinities before the 12 May 2008 Wenchuan Ms8.0 earthquake is studied. Based on the digital seismic waveform data observed from regional seismic networks and mobile stations, the focal mechanism solutions are determined. Our analysis results show that the seismicities of Longmenshan fault zone before the 12 May 2008 Wenchuan earthquake were in stable state. No obvious phenomena of seismic activity intensifying appeared. According to focal mechanism solutions of some small earthquakes before the 12 May 2008 Wenchuan earthquake, the direction of principal compressive stress P-axis is WNW-ESE. The two hypocenter fault planes are NE-striking and NW-striking. The plane of NE direction is among N50°-70°E, the dip angles of fault planes are 60°-70° and it is very steep. The faultings of most earthquakes are dominantly characterized by dip-slip reverse and small part of faultings present strike-slip. The azimuths of principal compressive stress, the strikes of source fault planes and the dislocation types calculated from some small earthquakes before the 12 May 2008 Wenchuan earthquake are in accordance with that of the main shock. The average stress field of micro-rupture along the Longmenshan fault zone before the great earthquake is also consistent with that calculated from main shock. Zipingpu dam is located in the east side 20 km from the initial rupture area of the 12 May 2008 Wenchuan earthquake. The activity increment of small earthquakes in the Zipingpu dam is in the period of water discharging. The source parameter results of the small earthquakes which occurred near the initial rupture area of the 12 May 2008 Wenchuan earthquake indicate that the focal depths are 5 to 14 km and the source parameters are identical with that of earthquake.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant No.61373126the Natural Science Foundation of Jiangsu Province of China under Grant No.BK20131107the Fundamental Research Funds for the Central Universities under Grant No.JUSRP51510
文摘This paper proposes a trust ant colony routing algorithm by introducing a node trust evaluation model based on the D-S evidence theory into the ant colony routing protocol to improve the security of wireless sensor networks. To reduce the influence of conflict evidences caused by malicious nods, the consistent intensity is introduced to preprocess conflict evidences before using the D-S combination rule to improve the reliability of the D-S based trust evaluation. The nodes with high trust values will be selected as the routing nodes to insure the routing security, and the trust values are used as heuristic functions of the ant colony routing algorithm. The simulation tests are conducted by using the network simulator NS2 to observe the outcomes of performance metrics of packets loss rate and average end-to-end delay etc. to indirectly evaluate the security issue under the attack of inside malicious nodes. The simulation results show that the proposed trust routing algorithm can efficiently resist malicious attacks in terms of keeping performances of the average end-to-end delay, the throughtput and the routing packet overhead under attacking from malicious nodes.
基金supported by the National Natural Science Foundation of China(Nos.51902188,52272224)Innovation Capacity Improvement Project of Small and Medium-Sized Technology-Based Enterprise of Shandong Province(No.2021TSGC1149)+2 种基金Youth Innovation Team Project of Shandong Provincial Education Department(No.10000082295015)Natural Science Doctoral Foundation of Shandong Province(No.ZR2019BEM019)the Future Program for Young Scholar of Shandong University。
文摘Selenium,an element belonging to the same group in the periodic table as sulfur,has a high electronic conductivity(1×10^(-5)S/cm)and a high volumetric energy density(3253 mA h/cm^(3)),which is a prospective cathode material for high-energy all-solid-state rechargeable batteries.However,its wide use is hindered by large volume expansion and low utilization rate.In this work,Se-infused nitrogen-doped hierarchical meso-microporous carbon composites(Se/NHPC)are prepared by a melt-diffusion process.Amorphous Se is uniformly dispersed in meso-micropores of NHPC with a high mass loading of 81%.All-solid-state Li-Se batteries fabricated by using Se/NHPC as the cathode,a Li-In alloy as the anode,and Li_(6)PS_(5)Cl as the solid-state electrolyte,deliver a highly reversible capacity of 621 m Ah/g(92%of theoretical capacity),a good rate capability and a high capacity retention value of 80.9%after 100 cycles.It is found that the capacity decay of Se cathode is mainly related to the interfacial degradation and the separation of Se from the carbon substrate,as suggested by the continuous increase of interfacial resistance and the structural transformation from amorphous Senchains to Se8rings initial discharge/charge cycle and then to the trigonally crystalline Se chains structure after the long-term cycles.
