Carbenes as one of the most important class of intermediates have been widely utilized in various organic synthetic transformations.Carbene insertion-initiated ring-opening reactions of cyclic ethers offer a valuable ...Carbenes as one of the most important class of intermediates have been widely utilized in various organic synthetic transformations.Carbene insertion-initiated ring-opening reactions of cyclic ethers offer a valuable strategy for constructing new carbon-oxygen bonds.In comparison with traditional thermal or metal-mediated carbene transfer reactions,visible-light-promoted multi-component reaction strategy provides a mild and eco-friendly approach to access densely functionalized molecules.Recently,visible-light-induced multi-component carbene transfer reactions of diazo compounds have been rapidly developed and attracted a great deal of research interest of chemists owing to their advantages of simple operation,mild condition,high atom economy and rich structural diversity.This paper summarizes the recent research progress on the visible-light-promoted multi-component carbene transfer reactions of diazo compounds via ring-opening of cyclic ethers with various nucleophiles.The reaction patterns of different nucleophiles and their corresponding mechanism are described in this review.The future research direction and challenges in this area are also discussed.展开更多
Hydrogels,owing to their porous network structure resembling the extracellular matrix(ECM),have become essential scaffold materials in the field of cartilage tissue engineering.Among them,gelatin methacrylate(GelMA)hy...Hydrogels,owing to their porous network structure resembling the extracellular matrix(ECM),have become essential scaffold materials in the field of cartilage tissue engineering.Among them,gelatin methacrylate(GelMA)hydrogels are widely used in bioink development due to their excellent biocompatibility,biodegradability,and tunable photo-crosslinking properties.However,the high biocompatibility of pure GelMA often comes at the cost of mechanical strength,limiting its applicability in cartilage regeneration.To overcome this trade-off,this study developed composite bioinks based on GelMA,silk fibroin(SF),and polyethylene oxide(PEO)for fabricating porous hydrogel scaffolds,which were then systematically characterized in terms of morphology,porosity,hydrophilicity,mechanical strength,rheological behavior,printability,and cytocompatibility.In this design,PEO serves as a porogen to generate highly porous structures(porosity up to 88%),while SF compensates for the mechanical loss caused by PEO,enabling the scaffold to retain a compression strength of up to 29.10 kPa.Among the tested formulations,the 10%GelMA/1%SF/1.5%PEO(1%=0.01 g/mL)bioink exhibited excellent printability,mechanical integrity,and cytocompatibility,and it supported a robust deposition of collagenⅡand aggrecan by chondrocytes after printing.This work provides a versatile strategy for balancing the biocompatibility and mechanical robustness in bioinks,offering a promising platform for next-generation cartilage tissue engineering scaffolds.展开更多
In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrabilit...In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrability.By focusing on single-component decompositions within the potential BKP hierarchy,it has been observed that specific linear superpositions of decomposition solutions remain consistent with the underlying equations.Moreover,through the implementation of multi-component decompositions within the potential BKP hierarchy,successful endeavors have been undertaken to formulate linear superposition solutions and novel coupled Kd V-type systems that resist decoupling via alterations in dependent variables.展开更多
Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current method...Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current methods,however,are complicated and time-consuming,the mass production remains a chal-lenge.Herein,we proposed a new high-efficiency strategy for synthesis of MMB_(2)using molten aluminum as the medium for the first time.The prepared Al-containing multi-component borides(TiZrHfNbTa)B_(2)microcrystals had a homogeneous composition with a hexagonal AlB_(2)structure and ultra-high hardness value of∼35.3 GPa,which was much higher than data reported in the literature and the rule of mix-ture estimations.Furthermore,combined with the First-principles calculation results,we found that the Poisson’s ratio(v)values exhibit a clearly ascending trend from 0.17 at VEC=3.5 to 0.18 at VEC=3.4,then to 0.201 at VEC=3.2 with the increasing of Al content.This indicates that the intrinsic toughness of multi-component boride microcrystals is obviously enhanced by the trace-doped Al elements.Besides,the fabricated Al-containing multi-component boride microcrystals have superior oxidation activation en-ergy and structural stability.The enhanced oxidation resistance is mainly attributed to the formation of a protective Al2 O3 oxide layer and the lattice distortion,both of which lead to sluggish diffusion of O_(2).These findings propose a new unexplored avenue for the fabrication of MMB_(2)materials with supe-rior comprehensive performance including ultra-hardness and intrinsically improved thermo-mechanical properties.展开更多
The hardening mechanism of multi-component carbide ceramic has been investigated in detail through a combination of experiments,first-principles calculations,and ab initio molecular dynamics(AIMD).Eight dense carbide ...The hardening mechanism of multi-component carbide ceramic has been investigated in detail through a combination of experiments,first-principles calculations,and ab initio molecular dynamics(AIMD).Eight dense carbide ceramics were prepared by spark plasma sintering.Compulsorily,all the multi-component carbide samples have similar carbon content,grain size,and uniform compositional distribution by optimizing the sintering process and adjusting the initial raw materials.Hence the interference of other factors on the hardness of multi-component carbide ceramics is minimized.The effects of changes in the elemental species on the lattice distortion,bond strength,bonding properties,and electronic structure of multi-component carbide ceramics were thoroughly analyzed.These results show that the hardening of multi-component carbide ceramic can be attributed to the coupling of solid solution strengthening caused by lattice distortion and covalent bond strengthening.Besides,the“host lattice”of multi-component carbide ceramics is defined based on the concept of supporting lattice.The present work is of great significance for a deeper understanding of the hardening mechanism of multi-component carbide ceramics and the design of superhard multi-component carbides.展开更多
A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficie...A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficiently obtained in moderate to good yields at room temperature.This metal-free visiblelight-driven tandem reaction was conducted through proton-coupled electron transfer(PCET)process using water as the hydrogen donor and 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene(4CzIPN)as the photocatalyst.展开更多
The construction of a borehole correction library for the multi-component array induction tool in deviated boreholes involves extensive 3D forward modeling and typically requires significant computational resources.To...The construction of a borehole correction library for the multi-component array induction tool in deviated boreholes involves extensive 3D forward modeling and typically requires significant computational resources.To address this challenge,this paper proposes an efficient algorithm for the library construction based on the 3D finite volume method(FVM)and contraction high-order Born approximation(CHBA).First,the electromagnetic(EM)field solution region is divided into two symmetric subregions based on the symmetry of the correction library model and the EM field.Numerical solution on a single subregion,combined with the symmetry boundary extension technique,enhances the efficiency of the 3D numerical simulation.Second,three reference mud conductivities are selected based on the mud conductivity range,and the CHBA is applied to calculate the EM responses at all mud conductivity nodes rapidly.Third,the number of forward simulation operations is further reduced by exploiting the principle that models with different frequencies and different formation conductivities have equivalent EM responses.Numerical experiments demonstrate the correctness and feasibility of the proposed algorithm.Compared to conventional 3D modeling,the proposed algorithm achieves approximately a 20-fold speedup in library construction,effectively reducing computational resources and time consumption.展开更多
CB chondrite is a class of meteorite rich in metal composition,and its characteristics are obviously different from other chondrite groups.These meteorites are distinguished by their content of up to 60% to 70%FeNi me...CB chondrite is a class of meteorite rich in metal composition,and its characteristics are obviously different from other chondrite groups.These meteorites are distinguished by their content of up to 60% to 70%FeNi metals and sulfides,in addition to their extreme lack of volatile and moderately volatile elements,less refractory inclusions,and almost no fine-grained matrix.Sierra Gorda 013(SG013)is a metal-rich chondritic meteorite of the CBa type.It has two different lithologies within SG 013:Lithology 1and Lithology 2.Lithology 1 is an anomalous CBa chondrite containing chromite-pyroxene complex assemblage,whereas Lithology 2 is featured by recrystallization with small chondrules and contains much less iron nickel metal than Lithology 1.Although the two lithologies have essentially the same oxygen isotope composition,their structures are different from each other,suggesting that they probably underwent distinct formation and evolution processes from common precursors.In this study,the mineralogy of SG013 chondrites is studied by means of petrographic observation,semi-quantitative analysis of chemical composition,fabric identification of minerals and integrated mineral phase analysis,while studying the mineralogy of SG 013,and the fabric characteristics of SG 013 are studied in detail.Different from previous studies,here we find that Lithology 1 of SG 013 contains non-porphyritic chondrules and metallic silicate globules,while Lithology 2 not only contains nonporphyritic chondrules and metallic-silicate globules,but also porphyritic chondrules.In this thesis,Electron backscatter diffraction(EBSD)analysis of magnesium olivine in metal-silicate globules and porphyritic chondrules in L2 of SG 013 shows that some magnesium olivine form under conditions of lower temperature and faster strain rate during uniaxial compression,where deformation of the olivine is dominated by dislocation glide.However,at higher temperatures and slower strain rates,the fabric of B-axis([100])is concentrated,indicating that the porphyritic chondrules may be dominated by the compaction of olivine particles,leading to dynamic recrystallization in the peripheral region or outer layer of the magnesium olivine crystal.New grains formed by dynamic recrystallization occur at the edges of residual grains and,their orientation is controlled by stress.It is found that the formation position of magnesium olivine in different chondrules of SG 013 from the inside out,with the gradual reduction of stress and the gradual increase of temperature,these local physicochemical changes reveal the complex thermal history and dynamic processes that chondrules undergo during their formation and evolution.展开更多
Gas sensors are valuable tools for human applications,and extensive research has been conducted in this field.However,practical implementation has yet to be fully realized.In response,efforts have been made to explore...Gas sensors are valuable tools for human applications,and extensive research has been conducted in this field.However,practical implementation has yet to be fully realized.In response,efforts have been made to explore metal-organic frameworks(MOFs),a novel class of porous materials,as potential solutions.MOFs exhibit exceptional porosity and highly tunable chemical compositions and structures,giving rise to a wide range of unique physical and chemical properties.Significant progress has been achieved in developing MOF-based gas sensors,improving sensing performance for various gases.This review aims to provide a comprehensive understanding of MOF-based gas sensors,even for readers unfamiliar with MOFs and gas sensors.It covers the working principles of these sensors,fundamental concepts of MOFs,strategies for tuning MOF properties,fabrication techniques for MOF films,and recent studies on MOF and MOF-derivative gas sensors.Finally,current challenges,overlooked aspects,and future directions for fully exploiting the potential of MOFs in gas sensor development are discussed.展开更多
Fabric defect detection plays a vital role in ensuring textile quality.However,traditional manual inspection methods are often inefficient and inaccurate.To overcome these limitations,we propose FD-YOLO,an enhanced li...Fabric defect detection plays a vital role in ensuring textile quality.However,traditional manual inspection methods are often inefficient and inaccurate.To overcome these limitations,we propose FD-YOLO,an enhanced lightweight detection model based on the YOLOv11n framework.The proposed model introduces the Bi-level Routing Attention(BRAttention)mechanism to enhance defect feature extraction,enabling more detailed feature representation.It proposes Deep Progressive Cross-Scale Fusion Neck(DPCSFNeck)to better capture smallscale defects and incorporates a Multi-Scale Dilated Residual(MSDR)module to strengthen multi-scale feature representation.Furthermore,a Shared Detail-Enhanced Lightweight Head(SDELHead)is employed to reduce the risk of gradient explosion during training.Experimental results demonstrate that FD-YOLO achieves superior detection accuracy and Lightweight performance compared to the baseline YOLOv11n.展开更多
From 2 to 4 February 2026,the 58th edition of the show will bring together more than 1,100 exhibitors from 33 countries at Paris–Le Bourget Exhibition Centre.As a true sourcing platform,the event stands out for its d...From 2 to 4 February 2026,the 58th edition of the show will bring together more than 1,100 exhibitors from 33 countries at Paris–Le Bourget Exhibition Centre.As a true sourcing platform,the event stands out for its diversity,clear structure and operational efficiency,giving international buyers direct access to an offer tailored to their needs.展开更多
Off-axis aspherical mirrors are widely used in optical systems and precision measuring instruments,whereas off-axis aspherical mirrors with large sizes and off-axis are used in large optical systems such as astronomic...Off-axis aspherical mirrors are widely used in optical systems and precision measuring instruments,whereas off-axis aspherical mirrors with large sizes and off-axis are used in large optical systems such as astronomical telescopes and radio telescopes.However,if the off-axis amount of an off-axis aspherical mirror exceeds the capability of the machine tool,traditional rotary-turning machining methods are not applicable,and advanced computerized numerical control(CNC)machining methods,such as the slow-tool-servo method,must be im-plemented.This article proposes a non-conventional offset(NCO)fabrication method based on slow-tool-servo single-point diamond turning for machining off-axis aspherical surfaces with large off-axis amounts.This method is theoretically applicable to the machining of off-axis aspherical surfaces with any off-axis amount.NCO fab-rication is a simpler and more efficient path-planning solution for machining individual off-axis parabolic sur-faces.In addition,corresponding solutions for other types of aspherical surfaces are proposed using the NCO method.The turning depths of workpieces with different off-axis amounts at the same machining position are analyzed and compared.A specific measurement scheme for the NCO method is presented,and the experimental results indicate that the PV and RMS form errors are 0.658μm and 60 nm,respectively.This work demonstrates that the NCO method can effectively deal with the machining challenges of off-axis aspherical structures with large off-axis amounts.展开更多
The accretion of the Panama-ChocóBlock to the South American Plate partially drove the geological setting of the northern Andes.This event occurred in different collisional stages that are recorded in Oligocene-m...The accretion of the Panama-ChocóBlock to the South American Plate partially drove the geological setting of the northern Andes.This event occurred in different collisional stages that are recorded in Oligocene-middle Miocene deformed rocks of the inter-Andean valley between the Western and Central Cordilleras of Colombia.However,uncertainty remains about the age of the latest accretionary phases of the Panama-ChocóBlock.Poorly studied late Miocene volcanic rocks within the northern inter-Andean valley may provide key information to constrain the temporality of that final collision.Here,we study the deformational features of the~12-6 Ma extrusive rocks of the Combia Volcanic Province located in the northwestern Andes(Colombia).We present anisotropy of magnetic susceptibility(AMS)data for pyroclastic and volcanic rocks within the AmagáBasin,an inter-Andean depression with Oligocene-middle Miocene sedimentary rocks that recorded NW-SE compression and NE-SW simple shear caused by the Panama-ChocóBlock collision.We identified that the magnetic fabrics of the extrusive rocks of the Combia Volcanic Province reveal flow directions that indicate the occurrence of ancient volcanoes in the central axis of the AmagáBasin.Some of these fabrics do not contain any deformational features,whereas others record the same structural regime as the Oligocene-middle Miocene sedimentary rocks.We infer that variations in the intensity of the deformation promoted late Miocene local fault reactivations that,in contrast to the Oligocene-middle Miocene deformational events,did not affect the entire AmagáBasin.Age differences among the studied sections can also explain the different deformational patterns identified in the basin.Both interpretations suggest that the most significant collisional events of the Panama-ChocóBlock occurred in the Oligocene-middle Miocene,whereas the formation of the Combia Volcanic Province may have either followed or coincided with the latest stages of the accretion.展开更多
The strength-ductility synergy in heterogeneous materials offers significant advantages,though their scalable and controlled fabrication remains challenging.This study introduces an in situ fabrication strategy for he...The strength-ductility synergy in heterogeneous materials offers significant advantages,though their scalable and controlled fabrication remains challenging.This study introduces an in situ fabrication strategy for heterogeneous lamellar titanium(HLT)alloy via laser powder bed fusion of a powder mixture consisting of Ti6Al4V(TC4)and 3 wt%Fe.By periodically varying the scanning velocity between layers,a heterogeneous lamellar microstructure is achieved due to the unique Fe distribution originating from the various volumetric energy densities(VEDs).Consequently,the HLT achieves high yield strength(1036 MPa)and ultimate tensile strength(1419 MPa)without compromising uniform elongation(UE),surpassing most TC4 alloys.The high strength may be attributed to precipitation strengthening originating from the nano-sizedαandωprecipitates,while the high UE and work hardening arise from the strain-induced martensite(SIM)and strong hetero-deformation induced(HDI)stress.The denser dual-phase interfaces and smaller grains in the low VED layers contribute to the higher sensitivity to the SIM.A strain gradient between soft and hard layers evolves during loading,and it further enhances the HDI strengthening and SIM behavior.Through this work,the in situ fabrication method and the deformation mechanism of lamellar heterostructure could offer valuable reference for the optimization and application of heterogeneous materials.展开更多
A multi-component system has the long fixed maintenance time, so the opportunistic maintenance policy is adopted to put preventive replacement and corrective replacement together, so that the long fixed maintenance ti...A multi-component system has the long fixed maintenance time, so the opportunistic maintenance policy is adopted to put preventive replacement and corrective replacement together, so that the long fixed maintenance time can be shared by more than one component, and the system availability can be improved. Then, the generation characteristics of the random failure time are researched based on the replacement maintenance and the minima[ maintenance. Furthermore, by choosing the opportunistic replacement ages of each component as opti- mized variables, a simulation algorithm based on an opportunistic maintenance policy is designed to maximize the total availability. Finally, the simulation result shows the validity of the algorithm by an example.展开更多
This review focuses on the recent research progress in the multi-component assembly of luminescent rare earth hybrid materials, which is based on the luminescent rare earth compounds and two or more other building uni...This review focuses on the recent research progress in the multi-component assembly of luminescent rare earth hybrid materials, which is based on the luminescent rare earth compounds and two or more other building units, including the other photoactive species. It covers the multi-component luminescent rare earth hybrids which was assembled with different(a) organic-inorganic polymeric units,(b)nanoporous units,(c) nanoparticle composites or(d) other developing special units. Finally, future challenges and opportunities in this field are discussed. Herein it mainly focuses on the work of Yan's group in recent years.展开更多
A general scheme for generating a multi-component integrable equation hierarchy is proposed. A simple 3M- dimensional loop algebra ~X is produced. By taking advantage of ~X a new isospectral problem is established and...A general scheme for generating a multi-component integrable equation hierarchy is proposed. A simple 3M- dimensional loop algebra ~X is produced. By taking advantage of ~X a new isospectral problem is established and then by making use of the Tu scheme the multi-component Dirac equation hierarchy is obtained. Finally, an expanding loop algebra ~FM of the loop algebra ~X is presented. Based on the ~FM, the multi-component integrable coupling system of the multi-component Dirac equation hierarchy is investigated. The method in this paper can be applied to other nonlinear evolution equation hierarchies.展开更多
基金Science and Technology Foundation of Guizhou Province(No.QKHJC-ZK[2024]654)Guizhou Provincial University Key Laboratory of Advanced Functional Electronic Materials(No.QJ[2023]021).
文摘Carbenes as one of the most important class of intermediates have been widely utilized in various organic synthetic transformations.Carbene insertion-initiated ring-opening reactions of cyclic ethers offer a valuable strategy for constructing new carbon-oxygen bonds.In comparison with traditional thermal or metal-mediated carbene transfer reactions,visible-light-promoted multi-component reaction strategy provides a mild and eco-friendly approach to access densely functionalized molecules.Recently,visible-light-induced multi-component carbene transfer reactions of diazo compounds have been rapidly developed and attracted a great deal of research interest of chemists owing to their advantages of simple operation,mild condition,high atom economy and rich structural diversity.This paper summarizes the recent research progress on the visible-light-promoted multi-component carbene transfer reactions of diazo compounds via ring-opening of cyclic ethers with various nucleophiles.The reaction patterns of different nucleophiles and their corresponding mechanism are described in this review.The future research direction and challenges in this area are also discussed.
基金supported by the Project(No.JCKY2024408C010)the Shanxi Province Key Research and Development Project(No.202302130501006)+4 种基金the National Natural Science Foundation of China(Nos.82403350,51975400,62031022)the Shanxi Provincial Key Medical Scientific Research Project(No.2020XM06)the Shanxi Provincial Basic Research Project(No.202103021223040)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2021L044)the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(No.2022SX-TD026),China.
文摘Hydrogels,owing to their porous network structure resembling the extracellular matrix(ECM),have become essential scaffold materials in the field of cartilage tissue engineering.Among them,gelatin methacrylate(GelMA)hydrogels are widely used in bioink development due to their excellent biocompatibility,biodegradability,and tunable photo-crosslinking properties.However,the high biocompatibility of pure GelMA often comes at the cost of mechanical strength,limiting its applicability in cartilage regeneration.To overcome this trade-off,this study developed composite bioinks based on GelMA,silk fibroin(SF),and polyethylene oxide(PEO)for fabricating porous hydrogel scaffolds,which were then systematically characterized in terms of morphology,porosity,hydrophilicity,mechanical strength,rheological behavior,printability,and cytocompatibility.In this design,PEO serves as a porogen to generate highly porous structures(porosity up to 88%),while SF compensates for the mechanical loss caused by PEO,enabling the scaffold to retain a compression strength of up to 29.10 kPa.Among the tested formulations,the 10%GelMA/1%SF/1.5%PEO(1%=0.01 g/mL)bioink exhibited excellent printability,mechanical integrity,and cytocompatibility,and it supported a robust deposition of collagenⅡand aggrecan by chondrocytes after printing.This work provides a versatile strategy for balancing the biocompatibility and mechanical robustness in bioinks,offering a promising platform for next-generation cartilage tissue engineering scaffolds.
基金sponsored by the National Natural Science Foundations of China under Grant Nos.12301315,12235007,11975131the Zhejiang Provincial Natural Science Foundation of China under Grant No.LQ20A010009。
文摘In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrability.By focusing on single-component decompositions within the potential BKP hierarchy,it has been observed that specific linear superpositions of decomposition solutions remain consistent with the underlying equations.Moreover,through the implementation of multi-component decompositions within the potential BKP hierarchy,successful endeavors have been undertaken to formulate linear superposition solutions and novel coupled Kd V-type systems that resist decoupling via alterations in dependent variables.
基金financially supported by the National Natural Science Foundation of China(Nos.52271033 and 52071179)the Key program of National Natural Science Foundation of China(No.51931003)+2 种基金Natural Science Foundation of Jiangsu Province,China(No.BK20221493)Jiangsu Province Leading Edge Technology Basic Research Major Project(No.BK20222014)Foundation of“Qinglan Project”for Colleges and Universities in Jiangsu Province.
文摘Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current methods,however,are complicated and time-consuming,the mass production remains a chal-lenge.Herein,we proposed a new high-efficiency strategy for synthesis of MMB_(2)using molten aluminum as the medium for the first time.The prepared Al-containing multi-component borides(TiZrHfNbTa)B_(2)microcrystals had a homogeneous composition with a hexagonal AlB_(2)structure and ultra-high hardness value of∼35.3 GPa,which was much higher than data reported in the literature and the rule of mix-ture estimations.Furthermore,combined with the First-principles calculation results,we found that the Poisson’s ratio(v)values exhibit a clearly ascending trend from 0.17 at VEC=3.5 to 0.18 at VEC=3.4,then to 0.201 at VEC=3.2 with the increasing of Al content.This indicates that the intrinsic toughness of multi-component boride microcrystals is obviously enhanced by the trace-doped Al elements.Besides,the fabricated Al-containing multi-component boride microcrystals have superior oxidation activation en-ergy and structural stability.The enhanced oxidation resistance is mainly attributed to the formation of a protective Al2 O3 oxide layer and the lattice distortion,both of which lead to sluggish diffusion of O_(2).These findings propose a new unexplored avenue for the fabrication of MMB_(2)materials with supe-rior comprehensive performance including ultra-hardness and intrinsically improved thermo-mechanical properties.
基金financially supported by the National Natural Science Foundation of China(Nos.52032002,52372060,51972081,and U22A20128)the National Safety Academic Foundation(No.U2130103)+1 种基金the National Key Laboratory of Precision Hot Processing of Metals(No.61429092300305)Heilongjiang Touyan Team Program are gratefully acknowledged.
文摘The hardening mechanism of multi-component carbide ceramic has been investigated in detail through a combination of experiments,first-principles calculations,and ab initio molecular dynamics(AIMD).Eight dense carbide ceramics were prepared by spark plasma sintering.Compulsorily,all the multi-component carbide samples have similar carbon content,grain size,and uniform compositional distribution by optimizing the sintering process and adjusting the initial raw materials.Hence the interference of other factors on the hardness of multi-component carbide ceramics is minimized.The effects of changes in the elemental species on the lattice distortion,bond strength,bonding properties,and electronic structure of multi-component carbide ceramics were thoroughly analyzed.These results show that the hardening of multi-component carbide ceramic can be attributed to the coupling of solid solution strengthening caused by lattice distortion and covalent bond strengthening.Besides,the“host lattice”of multi-component carbide ceramics is defined based on the concept of supporting lattice.The present work is of great significance for a deeper understanding of the hardening mechanism of multi-component carbide ceramics and the design of superhard multi-component carbides.
基金supported by Sichuan Science and Technology Program(No.2023NSFSC0101)the 2024 Provincial platform project of Chengdu Normal University(No.GNFZ202404)+1 种基金Natural Science Foundation of Shandong Province(No.ZR2021MB065)National Natural Science Foundation of China(No.22101237)。
文摘A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficiently obtained in moderate to good yields at room temperature.This metal-free visiblelight-driven tandem reaction was conducted through proton-coupled electron transfer(PCET)process using water as the hydrogen donor and 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene(4CzIPN)as the photocatalyst.
基金funded by the Forward-looking Basic Science and Technology Research Project of PetroChina Company Limited(2025DJ104)the National Natural Science Foundation of China(42174150)the National Science and Technology Major Project for Deep Earth Probe and Mineral Resources Exploration(2024ZD1003005).
文摘The construction of a borehole correction library for the multi-component array induction tool in deviated boreholes involves extensive 3D forward modeling and typically requires significant computational resources.To address this challenge,this paper proposes an efficient algorithm for the library construction based on the 3D finite volume method(FVM)and contraction high-order Born approximation(CHBA).First,the electromagnetic(EM)field solution region is divided into two symmetric subregions based on the symmetry of the correction library model and the EM field.Numerical solution on a single subregion,combined with the symmetry boundary extension technique,enhances the efficiency of the 3D numerical simulation.Second,three reference mud conductivities are selected based on the mud conductivity range,and the CHBA is applied to calculate the EM responses at all mud conductivity nodes rapidly.Third,the number of forward simulation operations is further reduced by exploiting the principle that models with different frequencies and different formation conductivities have equivalent EM responses.Numerical experiments demonstrate the correctness and feasibility of the proposed algorithm.Compared to conventional 3D modeling,the proposed algorithm achieves approximately a 20-fold speedup in library construction,effectively reducing computational resources and time consumption.
基金Chinese Academy of Science,XDB 41000000,Chunhui Li。
文摘CB chondrite is a class of meteorite rich in metal composition,and its characteristics are obviously different from other chondrite groups.These meteorites are distinguished by their content of up to 60% to 70%FeNi metals and sulfides,in addition to their extreme lack of volatile and moderately volatile elements,less refractory inclusions,and almost no fine-grained matrix.Sierra Gorda 013(SG013)is a metal-rich chondritic meteorite of the CBa type.It has two different lithologies within SG 013:Lithology 1and Lithology 2.Lithology 1 is an anomalous CBa chondrite containing chromite-pyroxene complex assemblage,whereas Lithology 2 is featured by recrystallization with small chondrules and contains much less iron nickel metal than Lithology 1.Although the two lithologies have essentially the same oxygen isotope composition,their structures are different from each other,suggesting that they probably underwent distinct formation and evolution processes from common precursors.In this study,the mineralogy of SG013 chondrites is studied by means of petrographic observation,semi-quantitative analysis of chemical composition,fabric identification of minerals and integrated mineral phase analysis,while studying the mineralogy of SG 013,and the fabric characteristics of SG 013 are studied in detail.Different from previous studies,here we find that Lithology 1 of SG 013 contains non-porphyritic chondrules and metallic silicate globules,while Lithology 2 not only contains nonporphyritic chondrules and metallic-silicate globules,but also porphyritic chondrules.In this thesis,Electron backscatter diffraction(EBSD)analysis of magnesium olivine in metal-silicate globules and porphyritic chondrules in L2 of SG 013 shows that some magnesium olivine form under conditions of lower temperature and faster strain rate during uniaxial compression,where deformation of the olivine is dominated by dislocation glide.However,at higher temperatures and slower strain rates,the fabric of B-axis([100])is concentrated,indicating that the porphyritic chondrules may be dominated by the compaction of olivine particles,leading to dynamic recrystallization in the peripheral region or outer layer of the magnesium olivine crystal.New grains formed by dynamic recrystallization occur at the edges of residual grains and,their orientation is controlled by stress.It is found that the formation position of magnesium olivine in different chondrules of SG 013 from the inside out,with the gradual reduction of stress and the gradual increase of temperature,these local physicochemical changes reveal the complex thermal history and dynamic processes that chondrules undergo during their formation and evolution.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(RS-2024-00333650)supported by basic science research program through the National Research Foundation of Korea funded by the Ministry of Education(NRF-2019R1A6A1A11055660)+1 种基金supported by the Technology Innovation Program(“20013621”,Center for Super Critical Material Industrial Technology)funded By the Ministry of Trade,Industry&Energy(MOTIE,Korea)supported by Strategic Networking&Development Program funded by the Ministry of Science and ICT through the National Research Foundation of Korea(RS-2023-00268523)。
文摘Gas sensors are valuable tools for human applications,and extensive research has been conducted in this field.However,practical implementation has yet to be fully realized.In response,efforts have been made to explore metal-organic frameworks(MOFs),a novel class of porous materials,as potential solutions.MOFs exhibit exceptional porosity and highly tunable chemical compositions and structures,giving rise to a wide range of unique physical and chemical properties.Significant progress has been achieved in developing MOF-based gas sensors,improving sensing performance for various gases.This review aims to provide a comprehensive understanding of MOF-based gas sensors,even for readers unfamiliar with MOFs and gas sensors.It covers the working principles of these sensors,fundamental concepts of MOFs,strategies for tuning MOF properties,fabrication techniques for MOF films,and recent studies on MOF and MOF-derivative gas sensors.Finally,current challenges,overlooked aspects,and future directions for fully exploiting the potential of MOFs in gas sensor development are discussed.
基金financially supported by the Fujian Provincial Department of Science and Technology,the Collaborative Innovation Platform Project for Key Technologies of Smart Warehousing and Logistics Systems in the Fuzhou-Xiamen-Quanzhou National Independent Innovation Demonstration Zone(No.2025E3024).
文摘Fabric defect detection plays a vital role in ensuring textile quality.However,traditional manual inspection methods are often inefficient and inaccurate.To overcome these limitations,we propose FD-YOLO,an enhanced lightweight detection model based on the YOLOv11n framework.The proposed model introduces the Bi-level Routing Attention(BRAttention)mechanism to enhance defect feature extraction,enabling more detailed feature representation.It proposes Deep Progressive Cross-Scale Fusion Neck(DPCSFNeck)to better capture smallscale defects and incorporates a Multi-Scale Dilated Residual(MSDR)module to strengthen multi-scale feature representation.Furthermore,a Shared Detail-Enhanced Lightweight Head(SDELHead)is employed to reduce the risk of gradient explosion during training.Experimental results demonstrate that FD-YOLO achieves superior detection accuracy and Lightweight performance compared to the baseline YOLOv11n.
文摘From 2 to 4 February 2026,the 58th edition of the show will bring together more than 1,100 exhibitors from 33 countries at Paris–Le Bourget Exhibition Centre.As a true sourcing platform,the event stands out for its diversity,clear structure and operational efficiency,giving international buyers direct access to an offer tailored to their needs.
基金Supported by National Key R&D Program of China(Grant No.2023YFE0203800)the National Natural Science Foundation of China(Grant No.52105482).
文摘Off-axis aspherical mirrors are widely used in optical systems and precision measuring instruments,whereas off-axis aspherical mirrors with large sizes and off-axis are used in large optical systems such as astronomical telescopes and radio telescopes.However,if the off-axis amount of an off-axis aspherical mirror exceeds the capability of the machine tool,traditional rotary-turning machining methods are not applicable,and advanced computerized numerical control(CNC)machining methods,such as the slow-tool-servo method,must be im-plemented.This article proposes a non-conventional offset(NCO)fabrication method based on slow-tool-servo single-point diamond turning for machining off-axis aspherical surfaces with large off-axis amounts.This method is theoretically applicable to the machining of off-axis aspherical surfaces with any off-axis amount.NCO fab-rication is a simpler and more efficient path-planning solution for machining individual off-axis parabolic sur-faces.In addition,corresponding solutions for other types of aspherical surfaces are proposed using the NCO method.The turning depths of workpieces with different off-axis amounts at the same machining position are analyzed and compared.A specific measurement scheme for the NCO method is presented,and the experimental results indicate that the PV and RMS form errors are 0.658μm and 60 nm,respectively.This work demonstrates that the NCO method can effectively deal with the machining challenges of off-axis aspherical structures with large off-axis amounts.
基金supported financially by the National Natural Science Foundation of China (Grants W2433104 to V.A.P. and42225402 to J.L.)the China Postdoctoral Science Foundation(Grant 2024M753205 to V.A.P.)+4 种基金the Institute of Geology and Geophysics of the Chinese Academy of Sciences (International Fellowship for Postdoctoral Researchers, Grant 2025PD02 to V.A.P.)an association between ECOS-NORD (France)Colciencias/Icetex (Colombia)(Grant C12U01 to M.I.M.)a junior fellowship scheme of Colciencias (Colombia)(Grant 706-2015 to V.A.P.)supported the undergraduate final project of A.T
文摘The accretion of the Panama-ChocóBlock to the South American Plate partially drove the geological setting of the northern Andes.This event occurred in different collisional stages that are recorded in Oligocene-middle Miocene deformed rocks of the inter-Andean valley between the Western and Central Cordilleras of Colombia.However,uncertainty remains about the age of the latest accretionary phases of the Panama-ChocóBlock.Poorly studied late Miocene volcanic rocks within the northern inter-Andean valley may provide key information to constrain the temporality of that final collision.Here,we study the deformational features of the~12-6 Ma extrusive rocks of the Combia Volcanic Province located in the northwestern Andes(Colombia).We present anisotropy of magnetic susceptibility(AMS)data for pyroclastic and volcanic rocks within the AmagáBasin,an inter-Andean depression with Oligocene-middle Miocene sedimentary rocks that recorded NW-SE compression and NE-SW simple shear caused by the Panama-ChocóBlock collision.We identified that the magnetic fabrics of the extrusive rocks of the Combia Volcanic Province reveal flow directions that indicate the occurrence of ancient volcanoes in the central axis of the AmagáBasin.Some of these fabrics do not contain any deformational features,whereas others record the same structural regime as the Oligocene-middle Miocene sedimentary rocks.We infer that variations in the intensity of the deformation promoted late Miocene local fault reactivations that,in contrast to the Oligocene-middle Miocene deformational events,did not affect the entire AmagáBasin.Age differences among the studied sections can also explain the different deformational patterns identified in the basin.Both interpretations suggest that the most significant collisional events of the Panama-ChocóBlock occurred in the Oligocene-middle Miocene,whereas the formation of the Combia Volcanic Province may have either followed or coincided with the latest stages of the accretion.
基金financially supported by the National Natural Science Foundation of China(No.52375347)Shanghai Pujiang Programme(No.8003PJD023)Natural Science Foundation of Ningbo(Grant No.2023J008)。
文摘The strength-ductility synergy in heterogeneous materials offers significant advantages,though their scalable and controlled fabrication remains challenging.This study introduces an in situ fabrication strategy for heterogeneous lamellar titanium(HLT)alloy via laser powder bed fusion of a powder mixture consisting of Ti6Al4V(TC4)and 3 wt%Fe.By periodically varying the scanning velocity between layers,a heterogeneous lamellar microstructure is achieved due to the unique Fe distribution originating from the various volumetric energy densities(VEDs).Consequently,the HLT achieves high yield strength(1036 MPa)and ultimate tensile strength(1419 MPa)without compromising uniform elongation(UE),surpassing most TC4 alloys.The high strength may be attributed to precipitation strengthening originating from the nano-sizedαandωprecipitates,while the high UE and work hardening arise from the strain-induced martensite(SIM)and strong hetero-deformation induced(HDI)stress.The denser dual-phase interfaces and smaller grains in the low VED layers contribute to the higher sensitivity to the SIM.A strain gradient between soft and hard layers evolves during loading,and it further enhances the HDI strengthening and SIM behavior.Through this work,the in situ fabrication method and the deformation mechanism of lamellar heterostructure could offer valuable reference for the optimization and application of heterogeneous materials.
文摘A multi-component system has the long fixed maintenance time, so the opportunistic maintenance policy is adopted to put preventive replacement and corrective replacement together, so that the long fixed maintenance time can be shared by more than one component, and the system availability can be improved. Then, the generation characteristics of the random failure time are researched based on the replacement maintenance and the minima[ maintenance. Furthermore, by choosing the opportunistic replacement ages of each component as opti- mized variables, a simulation algorithm based on an opportunistic maintenance policy is designed to maximize the total availability. Finally, the simulation result shows the validity of the algorithm by an example.
基金Project supported by the National Natural Science Foundation of China(21571142)the Developing Science Fund of Tongji University,the Natural Science Foundation of Zhejiang Province(LQ14B010001)the Natural Science Foundation of Ningbo,China(2016A610105)
文摘This review focuses on the recent research progress in the multi-component assembly of luminescent rare earth hybrid materials, which is based on the luminescent rare earth compounds and two or more other building units, including the other photoactive species. It covers the multi-component luminescent rare earth hybrids which was assembled with different(a) organic-inorganic polymeric units,(b)nanoporous units,(c) nanoparticle composites or(d) other developing special units. Finally, future challenges and opportunities in this field are discussed. Herein it mainly focuses on the work of Yan's group in recent years.
文摘A general scheme for generating a multi-component integrable equation hierarchy is proposed. A simple 3M- dimensional loop algebra ~X is produced. By taking advantage of ~X a new isospectral problem is established and then by making use of the Tu scheme the multi-component Dirac equation hierarchy is obtained. Finally, an expanding loop algebra ~FM of the loop algebra ~X is presented. Based on the ~FM, the multi-component integrable coupling system of the multi-component Dirac equation hierarchy is investigated. The method in this paper can be applied to other nonlinear evolution equation hierarchies.
