Configuration information acquisition and matching are two important steps in the self-reconfiguring process of self-reconfigurable robots. The process of configuration information acquisition was introduced, and a se...Configuration information acquisition and matching are two important steps in the self-reconfiguring process of self-reconfigurable robots. The process of configuration information acquisition was introduced, and a self-reconfiguring configuration matching strategy based on graded optimization mechanism was proposed. The first-grade optimization was to search common connection between matching scheme and goal configuration. The second-grade optimization, whose object function was constructed in terms of configuration connectivity, was to search connnon topology according to the results of the first-grade optimization. The entire process of configuration information acquisition and matching was verified by an experiment and genetic algorithm （GA）. The result shows the accuracy of the configuration information acquisition and the effectiveness of the configuration matching method.展开更多
Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop mor...Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop morphological development and increase yield.Here,a three-year study was performed to verify the feasibility of adjusting row spacing to further enhance yield in densely planted soybeans.Of three row-spacing configurations(40-40,20-40,and 20-60 cm)and two planting densities(normal 180,000 plants ha 1 and high 270,000 plants ha 1).The differences in canopy structure,plant morphological development,photosynthetic capacity and their impact on yield were analyzed.Row spacing configurations have a significant effect on canopy transmittance(CT).The 20-60 cm row spacing configuration increased CT and creates a favorable canopy light environment,in which plant height is reduced,while branching is promoted.This approach reduces plant competition,optimizes the developments of leaf area per plant,specific leaf area,leaf area development rate,leaf area duration and photosynthetic physiological indices(F_(v)/F_(m),ETR,P_(n)).The significant increase of 11.9%-34.2%in canopy apparent photosynthesis(CAP)is attributed to the significant optimization of plant growth and photosynthetic physiology through CT,an important contributing factor to yield increases.The yield in the 20-60 cm treatment is 4.0%higher than in equidistant planting under normal planting density,but 5.9%under high density,primarily driven by CAP and pod number.These findings suggest that suitable row spacing configurations optimize the light environment for plants,promote source-sink transformation in soybeans,and further improve yield.In practice,a 20-60 cm row spacing configuration could be employed for high-density soybean planting to achieve a more substantial yield gain.展开更多
To obtain the Ti_(p)with different aspect ratios,the Ti_(p)/Mg-5Zn-0.3Ca composite prepared by semi-solid stir casting was subjected to extrusion at 220℃,180℃,and 140℃,respectively.Then,the effect of the Ti_(p)’s ...To obtain the Ti_(p)with different aspect ratios,the Ti_(p)/Mg-5Zn-0.3Ca composite prepared by semi-solid stir casting was subjected to extrusion at 220℃,180℃,and 140℃,respectively.Then,the effect of the Ti_(p)’s aspect ratio on the microstructure,mechanical properties,work hardening and softening behaviors of Ti_(p)/Mg-5Zn-0.3Ca composites was investigated.The results indicated that the Ti_(p)could be elongated obviously after low-temperature extrusion,and the aspect ratio of which would reach to 13.7:1 as the extrusion temperature deceased to 140℃.Then the“Ti/Mg”layer-like structure was formed in the Ti_(p)/Mg-5Zn-0.3Ca composite.Accompanied with the elongation of Ti_(p),the dynamic recrystallized grains and dynamic precipitates were both refined significantly,however,the dynamic recrystallization rate changed a little.The elongated Ti_(p)endowed the Ti_(p)/Mg-5Zn-0.3Ca composites with better matching of strength and toughness without the sacrifice of elongation and bending strain.Both the work hardening rate and softening rate of Ti_(p)/Mg-5Zn-0.3Ca composites increased with the increasing aspect ratio of Ti_(p).The formation of“Ti/Mg”layer-like structure contributed to the redistribution of strain from large aggregations to a network-like distribution,which effectively suppresses the initiation and propagation of micro-cracks,thus enhancing the plasticity of the Ti_(p)/Mg-5Zn-0.3Ca composites.展开更多
Electrocatalytic CO_(2)reduction(ECR)to produce value-added fuels and chemicals using renewable electricity is an emerging strategy to mitigate global warming and decrease reliance on fossil fuels.Among various ECR pr...Electrocatalytic CO_(2)reduction(ECR)to produce value-added fuels and chemicals using renewable electricity is an emerging strategy to mitigate global warming and decrease reliance on fossil fuels.Among various ECR products,liquid oxygenates(Oxys)are especially attractive due to their high energy density,high safety and transportability that could be adapted to the existing infrastructure and transportation system.However,efficiently generating these highly reduced oxygen-containing products by ECR remains challenging due to the complexity of coupled proton and electron transfer processes.In recent years,in-depth studies of reaction mechanisms have advanced the design of catalysts and the regulation of reaction systems for ECR to produce Oxys,Here,by focusing on the production of typical Oxys,such as methanol,acetic acid,ethanol,acetone,n-propanol,and isopropanol,we outline various reaction paths and key intermediates for the electrochemical conversion of CO_(2)into these target products.We also summarize the current research status and recent advances in catalysts based on their elemental composition,and consider recent studies on the change of catalyst geometry and electronic structure,as well as the optimization of reaction systems to increase ECR performance.Finally,we analyze the challenges in the field of ECR to Oxys and provide an outlook on future directions for high-efficiency catalyst prediction and design,as well as the development of advanced reaction systems.展开更多
In the context of the“dual carbon”goals,to address issues such as high energy consumption,high costs,and low power quality in the rapid development of electrified railways,this study focused on the China Railways Hi...In the context of the“dual carbon”goals,to address issues such as high energy consumption,high costs,and low power quality in the rapid development of electrified railways,this study focused on the China Railways High-Speed 5 Electric Multiple Unit and proposed a mathematical model and capacity optimization method for an onboard energy storage system using lithium batteries and supercapacitors as storage media.Firstly,considering the electrical characteristics,weight,and volume of the storage media,a mathematical model of the energy storage system was established.Secondly,to tackle problems related to energy consumption and power quality,an energy management strategy was proposed that comprehensively considers peak shaving and valley filling and power quality by controlling the charge/discharge thresholds of the storage system.Thecapacity optimization adopted a bilevel programming model,with the series/parallel number of storage modules as variables,considering constraints imposed by the Direct Current to Direct Current converter,train load,and space.An improved Particle Swarm Optimization algorithm and linear programming solver were used to solve specific cases.The results show that the proposed onboard energy storage system can effectively achieve energy savings,reduce consumption,and improve power qualitywhile meeting the load and space limitations of the train.展开更多
Hydroxyapatite nanoparticles(HAP NPs)were synthesized by a one‐step hydrothermal method.The surface of HAP NPs was grafted-SH and-COOH chelating groups via in situ surface‐modification with iminodiacetic acid(IDA)an...Hydroxyapatite nanoparticles(HAP NPs)were synthesized by a one‐step hydrothermal method.The surface of HAP NPs was grafted-SH and-COOH chelating groups via in situ surface‐modification with iminodiacetic acid(IDA)and 3‐mercaptopropyl trimethoxysilane(MPS)to afford dual surface‐capped nano‐amendment HAPIDA/MPS.The structure of HAP‐IDA/MPS was characterized,and its adsorption performance for Hg^(2+),Cu^(2+),Zn^(2+),Ni^(2+),Co^(2+),and Cd^(2+)was evaluated.The total adsorption capacity of 0.10 g HAP‐IDA/MPS nano‐amendment for Hg^(2+),Cu^(2+),Zn^(2+),Ni^(2+),Co^(2+),and Cd^(2+)with an initial mass concentration of 20 mg·L^(-1) reached 13.7 mg·g^(-1),about 4.3 times as much as that of HAP.Notably,HAP‐IDA/MPS nano‐amendment displayed the highest immobilization rate for Hg^(2+),possibly because of its chemical reaction with-SH to form sulfide,possessing the lowest solubility product constant among a variety of metal sulfides.展开更多
Filter capacitors play an important role in altern-ating current(AC)-line filtering for stabilizing voltage,sup-pressing harmonics,and improving power quality.However,traditional aluminum electrolytic capacitors(AECs)...Filter capacitors play an important role in altern-ating current(AC)-line filtering for stabilizing voltage,sup-pressing harmonics,and improving power quality.However,traditional aluminum electrolytic capacitors(AECs)suffer from a large size,short lifespan,low power density,and poor reliability,which limits their use.In contrast,ultrafast supercapacitors(SCs)are ideal for replacing commercial AECs because of their extremely high power densities,fast charging and discharging,and excellent high-frequency re-sponse.We review the design principles and key parameters for ultrafast supercapacitors and summarize research pro-gress in recent years from the aspects of electrode materials,electrolytes,and device configurations.The preparation,structures,and frequency response performance of electrode materials mainly consisting of carbon materials such as graphene and carbon nanotubes,conductive polymers,and transition metal compounds,are focused on.Finally,future research directions for ultrafast SCs are suggested.展开更多
The conformational and dynamical properties of a long semi-flexible active polymer chain confined in a circular cavity are studied by using Langevin dynamics simulation method.Results show that the steady radius of gy...The conformational and dynamical properties of a long semi-flexible active polymer chain confined in a circular cavity are studied by using Langevin dynamics simulation method.Results show that the steady radius of gyration of the polymer decreases monotonically with increasing the active force.Interestingly,the polymer forms stable compact spiral with directional rotation at the steady state when the active force is large.Both the radius of gyration and the angular velocity of the spiral are nearly independent of the cavity size,but show scaling relations with the active force and the polymer length.It is further found that the formation of the stable compact spiral in most cases is a two-step relaxation process,where the polymer first forms a metastable swelling quasi spiral and then transforms into the stable compacted spiral near the wall of the cavity.The relaxation time is mainly determined by the transformation of the swelling quasi spiral,and shows remarkable dependence on the size of the cavity.Specially,when the circumference of the circular is nearly equivalent to the polymer length,it is difficult for the polymer to form the compacted spiral,leading to a large relaxation time.The underlying mechanism of the formation of the compacted spiral is revealed.展开更多
With the increase in the quantity and scale of Static Random-Access Memory Field Programmable Gate Arrays (SRAM-based FPGAs) for aerospace application, the volume of FPGA configuration bit files that must be stored ha...With the increase in the quantity and scale of Static Random-Access Memory Field Programmable Gate Arrays (SRAM-based FPGAs) for aerospace application, the volume of FPGA configuration bit files that must be stored has increased dramatically. The use of compression techniques for these bitstream files is emerging as a key strategy to alleviate the burden on storage resources. Due to the severe resource constraints of space-based electronics and the unique application environment, the simplicity, efficiency and robustness of the decompression circuitry is also a key design consideration. Through comparative analysis current bitstream file compression technologies, this research suggests that the Lempel Ziv Oberhumer (LZO) compression algorithm is more suitable for satellite applications. This paper also delves into the compression process and format of the LZO compression algorithm, as well as the inherent characteristics of configuration bitstream files. We propose an improved algorithm based on LZO for bitstream file compression, which optimises the compression process by refining the format and reducing the offset. Furthermore, a low-cost, robust decompression hardware architecture is proposed based on this method. Experimental results show that the compression speed of the improved LZO algorithm is increased by 3%, the decompression hardware cost is reduced by approximately 60%, and the compression ratio is slightly reduced by 0.47%.展开更多
As a highly reactive reaction intermediate,surface gallium hydride(Ga–H)has garnered significant attention due to its critical role in various catalytic reactions.However,the detailed experimental characterization of...As a highly reactive reaction intermediate,surface gallium hydride(Ga–H)has garnered significant attention due to its critical role in various catalytic reactions.However,the detailed experimental characterization of this unique species remains challenging.Recently,we have demonstrated that solid-state NMR can be an effective tool for studying surface Ga–H.In this work,we report a comparative solid-state NMR study on H_(2) activation over different Ga_(2)O_(3) polymorphs,specificallyα-,β-andγ-Ga_(2)O_(3).^(1)H solid-state NMR enabled the identification of Ga–H species formed on all the three samples following high-temperature H_(2) treatment.The characteristic ^(1)H NMR signals of Ga–H species are resolved using J-coupling-based double-resonance NMR methods,revealing highly similar lineshapes of Ga–H for all the Ga_(2)O_(3) samples.This suggests potentially similar surface Ga–H configurations among different Ga_(2)O_(3) polymorphs.In addition,the local hydrogen environments on the oxide surfaces are further explored using two-dimensional(2D)^(1)H–^(1)H homonuclear correlation spectra,revealing multiple spatially proximate Ga–H and Ga–H/–OH pairs on different Ga_(2)O_(3) polymorphs.These findings provide insights into the potential mechanism of H_(2) dissociation.Overall,this work offers new perspectives on the local structure of surface Ga–H on Ga_(2)O_(3),and the analytical approach presented here can be further extended to the study of other Ga-based catalysts and other metal hydride species.展开更多
A distinguished category of operational fluids,known as hybrid nanofluids,occupies a prominent role among various fluid types owing to its superior heat transfer properties.By employing a dovetail fin profile,this wor...A distinguished category of operational fluids,known as hybrid nanofluids,occupies a prominent role among various fluid types owing to its superior heat transfer properties.By employing a dovetail fin profile,this work investigates the thermal reaction of a dynamic fin system to a hybrid nanofluid with shape-based properties,flowing uniformly at a velocity U.The analysis focuses on four distinct types of nanoparticles,i.e.,Al2O3,Ag,carbon nanotube(CNT),and graphene.Specifically,two of these particles exhibit a spherical shape,one possesses a cylindrical form,and the final type adopts a platelet morphology.The investigation delves into the pairing of these nanoparticles.The examination employs a combined approach to assess the constructional and thermal exchange characteristics of the hybrid nanofluid.The fin design,under the specified circumstances,gives rise to the derivation of a differential equation.The given equation is then transformed into a dimensionless form.Notably,the Hermite wavelet method is introduced for the first time to address the challenge posed by a moving fin submerged in a hybrid nanofluid with shape-dependent features.To validate the credibility of this research,the results obtained in this study are systematically compared with the numerical simulations.The examination discloses that the highest heat flux is achieved when combining nanoparticles with spherical and platelet shapes.展开更多
The introduction of machine learning algorithms has revolutionized the design of invisible devices,particularly in the intricate domain of elasto-dynamics.In this study,we proposed a core-shell configuration to realiz...The introduction of machine learning algorithms has revolutionized the design of invisible devices,particularly in the intricate domain of elasto-dynamics.In this study,we proposed a core-shell configuration to realize elastic sphere cloaks driven by a Bayesian optimization algorithm to pinpoint the optimal configuration with high precision.Numerical simulations in solid and aqueous environments were performed to validate the cloaking efficacy of our design and the parameters identified by the algorithm.The results closely agreed with the theoretical predictions,underscoring the robustness of the proposed method.This approach provides new insights into the design of elastic wave invisibility devices and has potential applications in underwater communication and sonar detection.展开更多
A substation is a complex coupled system composed of various electrical equipment.Compared with standalone equipment,there is a significant coupling effect in the seismic response of interconnected equipment.To addres...A substation is a complex coupled system composed of various electrical equipment.Compared with standalone equipment,there is a significant coupling effect in the seismic response of interconnected equipment.To address this issue,this study investigates the seismic interaction of substation equipment with multiple electrical configurations and proposes an improved seismic design method.First,the concept of the coupling coefficient is introduced,which is used to improve the Newmark-βmethod and response spectrum method for the seismic design of standalone equipment.Then,the finite element models of a substation system with multiple configurations are established,and the vibration characteristics and seismic responses of the interconnected equipment are investigated.Finally,the coupling coefficients are obtained by kernel density estimation of the response results under twenty seismic ground motions,and the effectiveness of the proposed method is verified through two numerical examples.The results show that the frequency coupling coefficients vary from 0.69 to 1.42,while the seismic action coupling coefficient has a wider range,changing from 1.04 to 3.91.The coupling effect amplifies the seismic response of higher-frequency equipment,and the amplification degree varies among different configurations for the same type of equipment.展开更多
By combining a concave-convex multi-pass cavity with solid-state nonlinear media for spectral broadening and a post-compression grating setup,we generated femtosecond pulses with high peak power density.Compared to th...By combining a concave-convex multi-pass cavity with solid-state nonlinear media for spectral broadening and a post-compression grating setup,we generated femtosecond pulses with high peak power density.Compared to the other traditional pulse compression technologies,the configuration is very compact with large tolerance for beam direction and spot size.The pulses with an average power of 80 W,a pulse width of 10.7 ps,and a repetition rate of 500 kHz are compressed to 842 fs with the configuration,and the compressed pulse duration approaches the Fourier transform limited pulse duration of 707 fs.展开更多
Immiscible bimetal systems,of which tungsten–copper(W–Cu)is a typical representative,have crucial applications in fields requiring both mechanical and physical properties.Nevertheless,it is a major challenge to dete...Immiscible bimetal systems,of which tungsten–copper(W–Cu)is a typical representative,have crucial applications in fields requiring both mechanical and physical properties.Nevertheless,it is a major challenge to determine how to give full play to the advantages of the two phases of the bimetal and achieve outstanding comprehensive properties.In this study,an ultrafine-grained W–Cu bimetal with spatially connected Cu and specific Wislands was fabricated through a designed powder-mixing process and subsequent rapid low-temperature sintering.The prepared bimetal concurrently has a high yield strength,large plastic strain,and high electrical conductivity.The stress distribution and strain response of individual phases in different types of W–Cu bimetals under loading were quantified by means of a simulation.The high yield strength of the reported bimetal results from the microstructure refinement and high contiguity of the grains in the W islands,which enhance the contribution of W to the total plastic deformation of the bimetal.The high electrical conductivity is attributed to the increased mean free path of the Cu and the reduced proportion of phase boundaries due to the specific phase combination of W islands and Cu.This work provides new insight into modulating phase configuration in immiscible metallic composites to achieve high-level multi-objective properties.展开更多
We investigate the sensitivity of a Rydberg atom-based microwave sensor under two polarization configurations as a function of local oscillator(LO)microwave field strength.By employing parallel and perpendicular align...We investigate the sensitivity of a Rydberg atom-based microwave sensor under two polarization configurations as a function of local oscillator(LO)microwave field strength.By employing parallel and perpendicular alignments of laser and microwave polarizations in our experimental setup,we study the Autler-Townes(AT)splitting spectrum and optical response of probe transmission,and analyze their sensing effects.The results show that the parallel polarization configuration offers higher gain and better sensitivity than the perpendicular configuration.We achieve a sensitivity of 4.150(69)nV·cm^(-1)·Hz^(-1/2)at an LO microwave field strength of 1.74 mV/cm.This work demonstrates the significant role of polarization alignment on the performance of Rydberg atom-based microwave sensors.展开更多
Two novel diketopiperazines(1 and 5),along with ten known compounds(2−4,6−12)demonstrating significant skin inflammation inhibition,were isolated from a marine-derived fungus identified as Aspergillus sp.FAZW0001.The ...Two novel diketopiperazines(1 and 5),along with ten known compounds(2−4,6−12)demonstrating significant skin inflammation inhibition,were isolated from a marine-derived fungus identified as Aspergillus sp.FAZW0001.The structural elucidation and configurational reassessments of compounds 1−5 were established through comprehensive spectral analyses,with their absolute configurations determined via single crystal X-ray diffraction using Cu Kαradiation,Marfey’s method,and comparison between experimental and calculated electronic circular dichroism(ECD)spectra.Compounds 1,2,and 8 exhibited significant anti-inflammatory activities in Propionibacterium acnes(P.acnes)-induced human monocyte cell lines.Compound 8 demonstrated the ability to down-regulate interleukin-1β(IL-1β)expression by inhibiting Toll-like receptor 2(TLR2)expression and modulating the activation of myeloid differentiation factor 88(MyD88),mitogen-activated protein kinase(MAPK),and nuclear factorκB(NF-κB)signaling pathways,thus reducing the cellular inflammatory response induced by P.acnes.Additionally,compound 8 showed the capacity to suppress mitochondrial reactive oxygen species(ROS)production and nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)inflammasome activation,thereby reducing IL-1βmaturation and secretion.A three-dimensional quantitative structure-activity relationships(3D-QSAR)model was applied to compounds 5−12 to analyze their anti-inflammatory structure-activity relationships.展开更多
As the environmental problems become increasingly serious,distributed electrical propulsion systems with higher aerodynamic efficiency and lower pollution emission have received extensive attention in recent years.The...As the environmental problems become increasingly serious,distributed electrical propulsion systems with higher aerodynamic efficiency and lower pollution emission have received extensive attention in recent years.The distributed electrical propulsion usually employs the new aero-propulsion integrated configuration.A simulation strategy for internal and external flow coupling based on the combination of lifting line theory and body force method is proposed.The lifting line theory and body force method as source term are embedded into the Navier-Stokes formulation.The lift and drag characteristics of the aero-propulsion coupling configuration are simulated.The results indicate that the coupling configuration has the most obvious lift augmentation at 12°angle of attack,which can provide an 11.11%increase in lift for the airfoil.At 0°angle of attack,the pressure difference on the lip parts provides the thrust component,which results in a lower drag coefficient.Additionally,the failure impact of a ducted fan at the middle or edge on aerodynamics is investigated.For the two failure conditions,the lift of the coupling configuration is decreased significantly by 27.85%and 26.14%respectively,and the lip thrust is decreased by 70.74%and 56.48%respectively.展开更多
Inflatable deployable structures inspired by origami have significant applications in space missions such as solar arrays and antennas.In this paper,a generalized Miura-ori tubular cell(GMTC)is presented as the basic ...Inflatable deployable structures inspired by origami have significant applications in space missions such as solar arrays and antennas.In this paper,a generalized Miura-ori tubular cell(GMTC)is presented as the basic cell to design a family of inflatable origami tubular structures with the targeted configuration.First,the classification of rigid foldable degree-4 vertices is studied thoroughly.Since the proposed GMTC is comprised of forming units(FU)and linking units(LU),types of FUs and LUs are investigated based on the classification of degree-4 vertices,respectively.The rigid foldability of the GMTC is presented by studying the kinematics of the FUs and LUs.Volume of the GMTC is analyzed to investigate multistable configurations of the basic cell.The variations in volume of the GMTC offer great potential for developing the inflatable tubular structure.Design method and parametric optimization of the tubular structure with targeted configuration are proposed.The feasibility of the approach is validated by the approximation of four different cases,namely parabolic,semicircular,trapezoidal,and straight-arc hybrid tubular structures.展开更多
To better clarify the impact of the integration of education,science and technology,and talent on the cultivation of top-notch innovative talents in universities,this study adopts the fuzzy-set Qualitative Comparative...To better clarify the impact of the integration of education,science and technology,and talent on the cultivation of top-notch innovative talents in universities,this study adopts the fuzzy-set Qualitative Comparative Analysis(fsQCA)method.Using 23 universities in China as the research sample,the findings reveal that:(1)none of the three individual factors,education,science and technology,or talent can independently constitute either a necessary or sufficient condition for high-quality cultivation of top-notch innovative talents;(2)the sufficient condition for achieving high-quality cultivation lies in specific configurations of multiple condition variables;(3)five configurations were identified,from which three distinct paths toward achieving high-quality cultivation were derived.Accordingly,different universities can,based on their own resource endowments and local contexts,select appropriate cultivation paths to effectively enhance the quality of top-notch innovative talent training.展开更多
基金the National High Technology Research and Development Programme of China(No.2006AA04Z220)National Natural Science Foundation of China(No.60705027)Program for Changjiang Scholars and Innovative Research Team in University(PCSIRT)(No.IRT0423)
文摘Configuration information acquisition and matching are two important steps in the self-reconfiguring process of self-reconfigurable robots. The process of configuration information acquisition was introduced, and a self-reconfiguring configuration matching strategy based on graded optimization mechanism was proposed. The first-grade optimization was to search common connection between matching scheme and goal configuration. The second-grade optimization, whose object function was constructed in terms of configuration connectivity, was to search connnon topology according to the results of the first-grade optimization. The entire process of configuration information acquisition and matching was verified by an experiment and genetic algorithm （GA）. The result shows the accuracy of the configuration information acquisition and the effectiveness of the configuration matching method.
基金supported by the Biological Breeding-National Science and Technology Major Project(2023ZD0403305)National Natural Science Foundation of China(32101845)+1 种基金the National Key Research and Development Program of China(2023YFE0105000)the China Agriculture Research System(CARS-04).
文摘Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop morphological development and increase yield.Here,a three-year study was performed to verify the feasibility of adjusting row spacing to further enhance yield in densely planted soybeans.Of three row-spacing configurations(40-40,20-40,and 20-60 cm)and two planting densities(normal 180,000 plants ha 1 and high 270,000 plants ha 1).The differences in canopy structure,plant morphological development,photosynthetic capacity and their impact on yield were analyzed.Row spacing configurations have a significant effect on canopy transmittance(CT).The 20-60 cm row spacing configuration increased CT and creates a favorable canopy light environment,in which plant height is reduced,while branching is promoted.This approach reduces plant competition,optimizes the developments of leaf area per plant,specific leaf area,leaf area development rate,leaf area duration and photosynthetic physiological indices(F_(v)/F_(m),ETR,P_(n)).The significant increase of 11.9%-34.2%in canopy apparent photosynthesis(CAP)is attributed to the significant optimization of plant growth and photosynthetic physiology through CT,an important contributing factor to yield increases.The yield in the 20-60 cm treatment is 4.0%higher than in equidistant planting under normal planting density,but 5.9%under high density,primarily driven by CAP and pod number.These findings suggest that suitable row spacing configurations optimize the light environment for plants,promote source-sink transformation in soybeans,and further improve yield.In practice,a 20-60 cm row spacing configuration could be employed for high-density soybean planting to achieve a more substantial yield gain.
基金supported by the“National Natural Science Foundation of China”(Grants.52271109 and 52001223)Support from the“National Key Research and Development Program for Young Scientists”(Grant.2021YFB3703300)+1 种基金the Major Special Plan for Science and Technology in Shanxi Province(202201050201012)the Special Fund Project for Guiding Local Science and Technology Development by the Central Government(Grant.YDZJSX2021B019)。
文摘To obtain the Ti_(p)with different aspect ratios,the Ti_(p)/Mg-5Zn-0.3Ca composite prepared by semi-solid stir casting was subjected to extrusion at 220℃,180℃,and 140℃,respectively.Then,the effect of the Ti_(p)’s aspect ratio on the microstructure,mechanical properties,work hardening and softening behaviors of Ti_(p)/Mg-5Zn-0.3Ca composites was investigated.The results indicated that the Ti_(p)could be elongated obviously after low-temperature extrusion,and the aspect ratio of which would reach to 13.7:1 as the extrusion temperature deceased to 140℃.Then the“Ti/Mg”layer-like structure was formed in the Ti_(p)/Mg-5Zn-0.3Ca composite.Accompanied with the elongation of Ti_(p),the dynamic recrystallized grains and dynamic precipitates were both refined significantly,however,the dynamic recrystallization rate changed a little.The elongated Ti_(p)endowed the Ti_(p)/Mg-5Zn-0.3Ca composites with better matching of strength and toughness without the sacrifice of elongation and bending strain.Both the work hardening rate and softening rate of Ti_(p)/Mg-5Zn-0.3Ca composites increased with the increasing aspect ratio of Ti_(p).The formation of“Ti/Mg”layer-like structure contributed to the redistribution of strain from large aggregations to a network-like distribution,which effectively suppresses the initiation and propagation of micro-cracks,thus enhancing the plasticity of the Ti_(p)/Mg-5Zn-0.3Ca composites.
基金financial supports from the National Natural Science Foundation of China(52201237)the Talent Introduction Project of Chinese Academy of Sciences(E344011)+4 种基金the Shenzhen High Level Talent Team Project(KQTD2022110109364705)the Joint Research Project of China Merchants Group and SIAT(E2Z1521)the Cross Institute Joint Research Youth Team Project of SIAT(E25427)National Natural Science Foundation of China(52402136)the China Postdoctoral Science Foundation(E325281005)。
文摘Electrocatalytic CO_(2)reduction(ECR)to produce value-added fuels and chemicals using renewable electricity is an emerging strategy to mitigate global warming and decrease reliance on fossil fuels.Among various ECR products,liquid oxygenates(Oxys)are especially attractive due to their high energy density,high safety and transportability that could be adapted to the existing infrastructure and transportation system.However,efficiently generating these highly reduced oxygen-containing products by ECR remains challenging due to the complexity of coupled proton and electron transfer processes.In recent years,in-depth studies of reaction mechanisms have advanced the design of catalysts and the regulation of reaction systems for ECR to produce Oxys,Here,by focusing on the production of typical Oxys,such as methanol,acetic acid,ethanol,acetone,n-propanol,and isopropanol,we outline various reaction paths and key intermediates for the electrochemical conversion of CO_(2)into these target products.We also summarize the current research status and recent advances in catalysts based on their elemental composition,and consider recent studies on the change of catalyst geometry and electronic structure,as well as the optimization of reaction systems to increase ECR performance.Finally,we analyze the challenges in the field of ECR to Oxys and provide an outlook on future directions for high-efficiency catalyst prediction and design,as well as the development of advanced reaction systems.
基金funded by the National Natural Science Foundation of China(52167013)the Key Program of Natural Science Foundation of Gansu Province(24JRRA225)Natural Science Foundation of Gansu Province(23JRRA891).
文摘In the context of the“dual carbon”goals,to address issues such as high energy consumption,high costs,and low power quality in the rapid development of electrified railways,this study focused on the China Railways High-Speed 5 Electric Multiple Unit and proposed a mathematical model and capacity optimization method for an onboard energy storage system using lithium batteries and supercapacitors as storage media.Firstly,considering the electrical characteristics,weight,and volume of the storage media,a mathematical model of the energy storage system was established.Secondly,to tackle problems related to energy consumption and power quality,an energy management strategy was proposed that comprehensively considers peak shaving and valley filling and power quality by controlling the charge/discharge thresholds of the storage system.Thecapacity optimization adopted a bilevel programming model,with the series/parallel number of storage modules as variables,considering constraints imposed by the Direct Current to Direct Current converter,train load,and space.An improved Particle Swarm Optimization algorithm and linear programming solver were used to solve specific cases.The results show that the proposed onboard energy storage system can effectively achieve energy savings,reduce consumption,and improve power qualitywhile meeting the load and space limitations of the train.
文摘Hydroxyapatite nanoparticles(HAP NPs)were synthesized by a one‐step hydrothermal method.The surface of HAP NPs was grafted-SH and-COOH chelating groups via in situ surface‐modification with iminodiacetic acid(IDA)and 3‐mercaptopropyl trimethoxysilane(MPS)to afford dual surface‐capped nano‐amendment HAPIDA/MPS.The structure of HAP‐IDA/MPS was characterized,and its adsorption performance for Hg^(2+),Cu^(2+),Zn^(2+),Ni^(2+),Co^(2+),and Cd^(2+)was evaluated.The total adsorption capacity of 0.10 g HAP‐IDA/MPS nano‐amendment for Hg^(2+),Cu^(2+),Zn^(2+),Ni^(2+),Co^(2+),and Cd^(2+)with an initial mass concentration of 20 mg·L^(-1) reached 13.7 mg·g^(-1),about 4.3 times as much as that of HAP.Notably,HAP‐IDA/MPS nano‐amendment displayed the highest immobilization rate for Hg^(2+),possibly because of its chemical reaction with-SH to form sulfide,possessing the lowest solubility product constant among a variety of metal sulfides.
文摘Filter capacitors play an important role in altern-ating current(AC)-line filtering for stabilizing voltage,sup-pressing harmonics,and improving power quality.However,traditional aluminum electrolytic capacitors(AECs)suffer from a large size,short lifespan,low power density,and poor reliability,which limits their use.In contrast,ultrafast supercapacitors(SCs)are ideal for replacing commercial AECs because of their extremely high power densities,fast charging and discharging,and excellent high-frequency re-sponse.We review the design principles and key parameters for ultrafast supercapacitors and summarize research pro-gress in recent years from the aspects of electrode materials,electrolytes,and device configurations.The preparation,structures,and frequency response performance of electrode materials mainly consisting of carbon materials such as graphene and carbon nanotubes,conductive polymers,and transition metal compounds,are focused on.Finally,future research directions for ultrafast SCs are suggested.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(No.LY20A040004)the National Natural Science Foundation of China(Nos.22203060 and 11974305).
文摘The conformational and dynamical properties of a long semi-flexible active polymer chain confined in a circular cavity are studied by using Langevin dynamics simulation method.Results show that the steady radius of gyration of the polymer decreases monotonically with increasing the active force.Interestingly,the polymer forms stable compact spiral with directional rotation at the steady state when the active force is large.Both the radius of gyration and the angular velocity of the spiral are nearly independent of the cavity size,but show scaling relations with the active force and the polymer length.It is further found that the formation of the stable compact spiral in most cases is a two-step relaxation process,where the polymer first forms a metastable swelling quasi spiral and then transforms into the stable compacted spiral near the wall of the cavity.The relaxation time is mainly determined by the transformation of the swelling quasi spiral,and shows remarkable dependence on the size of the cavity.Specially,when the circumference of the circular is nearly equivalent to the polymer length,it is difficult for the polymer to form the compacted spiral,leading to a large relaxation time.The underlying mechanism of the formation of the compacted spiral is revealed.
基金supported in part by the National Key Laboratory of Science and Technology on Space Microwave(Grant Nos.HTKJ2022KL504009 and HTKJ2022KL5040010).
文摘With the increase in the quantity and scale of Static Random-Access Memory Field Programmable Gate Arrays (SRAM-based FPGAs) for aerospace application, the volume of FPGA configuration bit files that must be stored has increased dramatically. The use of compression techniques for these bitstream files is emerging as a key strategy to alleviate the burden on storage resources. Due to the severe resource constraints of space-based electronics and the unique application environment, the simplicity, efficiency and robustness of the decompression circuitry is also a key design consideration. Through comparative analysis current bitstream file compression technologies, this research suggests that the Lempel Ziv Oberhumer (LZO) compression algorithm is more suitable for satellite applications. This paper also delves into the compression process and format of the LZO compression algorithm, as well as the inherent characteristics of configuration bitstream files. We propose an improved algorithm based on LZO for bitstream file compression, which optimises the compression process by refining the format and reducing the offset. Furthermore, a low-cost, robust decompression hardware architecture is proposed based on this method. Experimental results show that the compression speed of the improved LZO algorithm is increased by 3%, the decompression hardware cost is reduced by approximately 60%, and the compression ratio is slightly reduced by 0.47%.
基金financially supported by the National Key R&D Program of China(No.2021YFA1502803)the National Natural Science Foundation of China(Nos.22325405,22372160,22432005 and 22321002)Dalian Science and Technology Talent Innovation Program(No.2024RG009).
文摘As a highly reactive reaction intermediate,surface gallium hydride(Ga–H)has garnered significant attention due to its critical role in various catalytic reactions.However,the detailed experimental characterization of this unique species remains challenging.Recently,we have demonstrated that solid-state NMR can be an effective tool for studying surface Ga–H.In this work,we report a comparative solid-state NMR study on H_(2) activation over different Ga_(2)O_(3) polymorphs,specificallyα-,β-andγ-Ga_(2)O_(3).^(1)H solid-state NMR enabled the identification of Ga–H species formed on all the three samples following high-temperature H_(2) treatment.The characteristic ^(1)H NMR signals of Ga–H species are resolved using J-coupling-based double-resonance NMR methods,revealing highly similar lineshapes of Ga–H for all the Ga_(2)O_(3) samples.This suggests potentially similar surface Ga–H configurations among different Ga_(2)O_(3) polymorphs.In addition,the local hydrogen environments on the oxide surfaces are further explored using two-dimensional(2D)^(1)H–^(1)H homonuclear correlation spectra,revealing multiple spatially proximate Ga–H and Ga–H/–OH pairs on different Ga_(2)O_(3) polymorphs.These findings provide insights into the potential mechanism of H_(2) dissociation.Overall,this work offers new perspectives on the local structure of surface Ga–H on Ga_(2)O_(3),and the analytical approach presented here can be further extended to the study of other Ga-based catalysts and other metal hydride species.
文摘A distinguished category of operational fluids,known as hybrid nanofluids,occupies a prominent role among various fluid types owing to its superior heat transfer properties.By employing a dovetail fin profile,this work investigates the thermal reaction of a dynamic fin system to a hybrid nanofluid with shape-based properties,flowing uniformly at a velocity U.The analysis focuses on four distinct types of nanoparticles,i.e.,Al2O3,Ag,carbon nanotube(CNT),and graphene.Specifically,two of these particles exhibit a spherical shape,one possesses a cylindrical form,and the final type adopts a platelet morphology.The investigation delves into the pairing of these nanoparticles.The examination employs a combined approach to assess the constructional and thermal exchange characteristics of the hybrid nanofluid.The fin design,under the specified circumstances,gives rise to the derivation of a differential equation.The given equation is then transformed into a dimensionless form.Notably,the Hermite wavelet method is introduced for the first time to address the challenge posed by a moving fin submerged in a hybrid nanofluid with shape-dependent features.To validate the credibility of this research,the results obtained in this study are systematically compared with the numerical simulations.The examination discloses that the highest heat flux is achieved when combining nanoparticles with spherical and platelet shapes.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1407100 and 2020YFA0710100)the National Natural Science Foundation of China(Grant Nos.12374410 and 12361161667)。
文摘The introduction of machine learning algorithms has revolutionized the design of invisible devices,particularly in the intricate domain of elasto-dynamics.In this study,we proposed a core-shell configuration to realize elastic sphere cloaks driven by a Bayesian optimization algorithm to pinpoint the optimal configuration with high precision.Numerical simulations in solid and aqueous environments were performed to validate the cloaking efficacy of our design and the parameters identified by the algorithm.The results closely agreed with the theoretical predictions,underscoring the robustness of the proposed method.This approach provides new insights into the design of elastic wave invisibility devices and has potential applications in underwater communication and sonar detection.
基金National Natural Science Foundation of China under Grant No. 52378483the Fundamental Research Funds for the Central Universities under Grant No. DUT21JC07+1 种基金the Scientific Research Fund of Institute of Engineering MechanicsChina Earthquake Administration under Grant No. 2021D17
文摘A substation is a complex coupled system composed of various electrical equipment.Compared with standalone equipment,there is a significant coupling effect in the seismic response of interconnected equipment.To address this issue,this study investigates the seismic interaction of substation equipment with multiple electrical configurations and proposes an improved seismic design method.First,the concept of the coupling coefficient is introduced,which is used to improve the Newmark-βmethod and response spectrum method for the seismic design of standalone equipment.Then,the finite element models of a substation system with multiple configurations are established,and the vibration characteristics and seismic responses of the interconnected equipment are investigated.Finally,the coupling coefficients are obtained by kernel density estimation of the response results under twenty seismic ground motions,and the effectiveness of the proposed method is verified through two numerical examples.The results show that the frequency coupling coefficients vary from 0.69 to 1.42,while the seismic action coupling coefficient has a wider range,changing from 1.04 to 3.91.The coupling effect amplifies the seismic response of higher-frequency equipment,and the amplification degree varies among different configurations for the same type of equipment.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFA1604200 and 2022YFB4601101)the Beijing Municipal Commission of Science and Technology(Grant No.Z231100006623006)+1 种基金the Beijing Natural Science Foundation(Grant No.JQ21019)the National Natural Science Foundation of China(Grant Nos.12034020,11975001,12075034,and 12261131495)。
文摘By combining a concave-convex multi-pass cavity with solid-state nonlinear media for spectral broadening and a post-compression grating setup,we generated femtosecond pulses with high peak power density.Compared to the other traditional pulse compression technologies,the configuration is very compact with large tolerance for beam direction and spot size.The pulses with an average power of 80 W,a pulse width of 10.7 ps,and a repetition rate of 500 kHz are compressed to 842 fs with the configuration,and the compressed pulse duration approaches the Fourier transform limited pulse duration of 707 fs.
基金supported by the National Natural Science Foundation of China(92163107,52171061,and 52371128)the National Key Research and Development Program of China(2022YFB3708800 and 2021YFB3501502).
文摘Immiscible bimetal systems,of which tungsten–copper(W–Cu)is a typical representative,have crucial applications in fields requiring both mechanical and physical properties.Nevertheless,it is a major challenge to determine how to give full play to the advantages of the two phases of the bimetal and achieve outstanding comprehensive properties.In this study,an ultrafine-grained W–Cu bimetal with spatially connected Cu and specific Wislands was fabricated through a designed powder-mixing process and subsequent rapid low-temperature sintering.The prepared bimetal concurrently has a high yield strength,large plastic strain,and high electrical conductivity.The stress distribution and strain response of individual phases in different types of W–Cu bimetals under loading were quantified by means of a simulation.The high yield strength of the reported bimetal results from the microstructure refinement and high contiguity of the grains in the W islands,which enhance the contribution of W to the total plastic deformation of the bimetal.The high electrical conductivity is attributed to the increased mean free path of the Cu and the reduced proportion of phase boundaries due to the specific phase combination of W islands and Cu.This work provides new insight into modulating phase configuration in immiscible metallic composites to achieve high-level multi-objective properties.
基金supported by the Natural Science Foundation of Chongqing,China(Grant Nos.CSTB2024NSCQ-MSX0880 and CSTB2024NSCQ-MSX1187)the Fund from Chongqing University of Posts and Telecommunications(Grants Nos.A2024-33 and A2023-54).
文摘We investigate the sensitivity of a Rydberg atom-based microwave sensor under two polarization configurations as a function of local oscillator(LO)microwave field strength.By employing parallel and perpendicular alignments of laser and microwave polarizations in our experimental setup,we study the Autler-Townes(AT)splitting spectrum and optical response of probe transmission,and analyze their sensing effects.The results show that the parallel polarization configuration offers higher gain and better sensitivity than the perpendicular configuration.We achieve a sensitivity of 4.150(69)nV·cm^(-1)·Hz^(-1/2)at an LO microwave field strength of 1.74 mV/cm.This work demonstrates the significant role of polarization alignment on the performance of Rydberg atom-based microwave sensors.
基金supported by the National Natural Science Foundation of China(Nos.41876189 and 81703388)the State Key Laboratory of Bioreactor Engineering and Shanghai Collaborative Innovation Center for Biomanufacturing Technology.
文摘Two novel diketopiperazines(1 and 5),along with ten known compounds(2−4,6−12)demonstrating significant skin inflammation inhibition,were isolated from a marine-derived fungus identified as Aspergillus sp.FAZW0001.The structural elucidation and configurational reassessments of compounds 1−5 were established through comprehensive spectral analyses,with their absolute configurations determined via single crystal X-ray diffraction using Cu Kαradiation,Marfey’s method,and comparison between experimental and calculated electronic circular dichroism(ECD)spectra.Compounds 1,2,and 8 exhibited significant anti-inflammatory activities in Propionibacterium acnes(P.acnes)-induced human monocyte cell lines.Compound 8 demonstrated the ability to down-regulate interleukin-1β(IL-1β)expression by inhibiting Toll-like receptor 2(TLR2)expression and modulating the activation of myeloid differentiation factor 88(MyD88),mitogen-activated protein kinase(MAPK),and nuclear factorκB(NF-κB)signaling pathways,thus reducing the cellular inflammatory response induced by P.acnes.Additionally,compound 8 showed the capacity to suppress mitochondrial reactive oxygen species(ROS)production and nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)inflammasome activation,thereby reducing IL-1βmaturation and secretion.A three-dimensional quantitative structure-activity relationships(3D-QSAR)model was applied to compounds 5−12 to analyze their anti-inflammatory structure-activity relationships.
基金the funding support from the Taihang Laboratory,China(No.D2024-1-0201).
文摘As the environmental problems become increasingly serious,distributed electrical propulsion systems with higher aerodynamic efficiency and lower pollution emission have received extensive attention in recent years.The distributed electrical propulsion usually employs the new aero-propulsion integrated configuration.A simulation strategy for internal and external flow coupling based on the combination of lifting line theory and body force method is proposed.The lifting line theory and body force method as source term are embedded into the Navier-Stokes formulation.The lift and drag characteristics of the aero-propulsion coupling configuration are simulated.The results indicate that the coupling configuration has the most obvious lift augmentation at 12°angle of attack,which can provide an 11.11%increase in lift for the airfoil.At 0°angle of attack,the pressure difference on the lip parts provides the thrust component,which results in a lower drag coefficient.Additionally,the failure impact of a ducted fan at the middle or edge on aerodynamics is investigated.For the two failure conditions,the lift of the coupling configuration is decreased significantly by 27.85%and 26.14%respectively,and the lip thrust is decreased by 70.74%and 56.48%respectively.
基金supported by the National Natural Science Foundation of China(No.52222501,52075016,52192632)the Fundamental Research Funds for the Central Universities(Grant No.YWF-23-L-904).
文摘Inflatable deployable structures inspired by origami have significant applications in space missions such as solar arrays and antennas.In this paper,a generalized Miura-ori tubular cell(GMTC)is presented as the basic cell to design a family of inflatable origami tubular structures with the targeted configuration.First,the classification of rigid foldable degree-4 vertices is studied thoroughly.Since the proposed GMTC is comprised of forming units(FU)and linking units(LU),types of FUs and LUs are investigated based on the classification of degree-4 vertices,respectively.The rigid foldability of the GMTC is presented by studying the kinematics of the FUs and LUs.Volume of the GMTC is analyzed to investigate multistable configurations of the basic cell.The variations in volume of the GMTC offer great potential for developing the inflatable tubular structure.Design method and parametric optimization of the tubular structure with targeted configuration are proposed.The feasibility of the approach is validated by the approximation of four different cases,namely parabolic,semicircular,trapezoidal,and straight-arc hybrid tubular structures.
基金2022 Philosophy and Social Sciences Research Project for Higher Education Institutions“Research on Synergistic Education Pathways Integrating Labor Education and Innovation-Entrepreneurship Education in Universities during the New Era”(Project No.:2022SJSZ1174)2024 Jiangsu University Higher Education Planning and Development Research Project“Research on the Cultivation Model of Top-notch Innovative Talents in Local High-Level Universities from the Perspective of Education-Science-Technology-Talent Integration”(Project No.:G202406)。
文摘To better clarify the impact of the integration of education,science and technology,and talent on the cultivation of top-notch innovative talents in universities,this study adopts the fuzzy-set Qualitative Comparative Analysis(fsQCA)method.Using 23 universities in China as the research sample,the findings reveal that:(1)none of the three individual factors,education,science and technology,or talent can independently constitute either a necessary or sufficient condition for high-quality cultivation of top-notch innovative talents;(2)the sufficient condition for achieving high-quality cultivation lies in specific configurations of multiple condition variables;(3)five configurations were identified,from which three distinct paths toward achieving high-quality cultivation were derived.Accordingly,different universities can,based on their own resource endowments and local contexts,select appropriate cultivation paths to effectively enhance the quality of top-notch innovative talent training.
