The dynamic changes of land system in Huang - Huai - Hai Plain between 1988 and 2000 were researched in this paper. Spatial dominance econometric model was estabilished on 1 km cell to quantificafionally analyze the d...The dynamic changes of land system in Huang - Huai - Hai Plain between 1988 and 2000 were researched in this paper. Spatial dominance econometric model was estabilished on 1 km cell to quantificafionally analyze the driving-force for the dynamic change mechanism of land system, such as natural, social and economic factors. The future dynamic changes of land system in Huang - Huai - Hai Plain on each 1 km cell during 2000 to 2020 were stimulated by combining the dynamic changes of land system on each 1 km cell with different situations. The research indicated that the dynamic changes of land system structure changed mainly from the cultivated areas to building areas and industrial areas, and forest areas increased during this period. Although the revolutions of land system structure were different during 2000 to 2020 with the different referrence standard, ecological protection and economic development, the primary dynamic changes of land system structure were that the increase of building land areas with the decline cuhivaled land areas and the increase of woodlands.展开更多
The southem Yellow Sea is an important fishing ground, providing abundant fishery resources. However, overfishing and climate change have caused a decline in the resource and damaged the ecosystem. We developed an eco...The southem Yellow Sea is an important fishing ground, providing abundant fishery resources. However, overfishing and climate change have caused a decline in the resource and damaged the ecosystem. We developed an ecosystem model to analyze the trophic interactions and ecosystem structure and function to guide sustainable development of the ecosystem. Atrophic mass-balance model of the southern Yellow Sea during 2000-2001 was constructed using Ecopath with Ecosim software. We defined 22 important functional groups and studied their diet composition. The trophic levels of fish, shrimp, crabs, and cephalopods were between 2.78 and 4.39, and the mean trophic level of the fisheries was 3.24. The trophic flows within the food web occurred primarily in the lower trophic levels. The mean trophic transfer efficiency was 8.1%, of which 7.1% was from primary producers and 9.3% was from detritus within the ecosystem. The transfer efficiency between trophic levels II to III to IV to V to 〉V was 5.0%, 5.7%, 18.5%, and 19.7%-20.4%, respectively. Of the total flow, phytoplankton contributed 61% and detritus contributed 39%. Fishing is defined as a top predator within the ecosystem, and has a negative impact on most commercial species. Moreover, the ecosystem had a high gross efficiency of the fishery and a high value of primary production required to sustain the fishery. Together, our data suggest there is high fishing pressure in the southern Yellow Sea. Based on analysis of Odum＇s ecological parameters, this ecosystem was at an immature stage. Our results provide some insights into the structure and development of this ecosystem.展开更多
Based on the cognitive radar concept and the basic connotation of cognitive skywave over-the-horizon radar（SWOTHR）, the system structure and information processingmechanism about cognitive SWOTHR are researched. Amo...Based on the cognitive radar concept and the basic connotation of cognitive skywave over-the-horizon radar（SWOTHR）, the system structure and information processingmechanism about cognitive SWOTHR are researched. Amongthem, the hybrid network system architecture which is thedistributed configuration combining with the centralized cognition and its soft/hardware framework with the sense-detectionintegration are proposed, and the information processing framebased on the lens principle and its information processing flowwith receive-transmit joint adaption are designed, which buildand parse the work law for cognition and its self feedback adjustment with the lens focus model and five stages informationprocessing sequence. After that, the system simulation andthe performance analysis and comparison are provided, whichinitially proves the rationality and advantages of the proposedideas. Finally, four important development ideas of futureSWOTHR toward ＂high frequency intelligence information processing system＂ are discussed, which are scene information fusion, dynamic reconfigurable system, hierarchical and modulardesign, and sustainable development. Then the conclusion thatthe cognitive SWOTHR can cause the performance improvement is gotten.展开更多
Identifying the structure of protected mountain ecosystems is an important task for understanding conservation sustainability.The study area,the Firtina Valley,located in the Rize City on the Eastern Blacksea Coast,is...Identifying the structure of protected mountain ecosystems is an important task for understanding conservation sustainability.The study area,the Firtina Valley,located in the Rize City on the Eastern Blacksea Coast,is one of the biological hotspots and a National Park of Turkey.In order to identify the structure of mountain ecosystems,we generated a GIS database for the main environmental parameters of the study area,including elevation,slope and aspect layers for topographic structure,10year mean values of Normalized Difference Vegetation Index(NDVI),data for vegetation structure,annual mean temperature and precipitation layers for climatic structure,main soil groups for soil structure and stream flow accumulation,stream flow length and stream order layers for hydrological structure.To identify the complex relations among environmental factors in the study area a data reduction method is applied with Principal Component Analysis(PCA).PCA is performed using data of 16 layers from Geographical Information Systems(GIS).PCA analysis reduced 16 dimensions into 5 dimensions containing 75%of the variation in all data.It is also revealed that the topographic structure,mainly altitude,dominates the ecosystems of the Firtina Valley,but it should be considered that the interactions of environmental factors in an ecosystem dynamics are very complex.The ecosystem structure is determined by the environmental factors direct or indirect effects on energy regulation of an ecosystem.Therefore the relationship between topographic elements and other abiotic-biotic elements in the Firtina Valley are important for environmental assessment and sustainability of a protected area,and these effects are explained in this study.展开更多
Based on the seamless integration of broadband optical and wireless access networks,millimeter-wave Radio over Fiber(RoF)technology is considered to be a promising solution for the next generation access networks whic...Based on the seamless integration of broadband optical and wireless access networks,millimeter-wave Radio over Fiber(RoF)technology is considered to be a promising solution for the next generation access networks which will provide high capacity and flexibility with low cost.But due to its large cost to realize,the system architecture needs to be optimized.In the millimeter-wave optical generation part,optical heterodyning method can be introduced to generate a high-frequency millimeter-wave signal using a low-frequency signal source.And the system efficiency can be greatly improved based on injection-locking of a semiconductor laser.In the downlink,the transmission distance can be greatly enhanced using single-sideband modulation.And the single-mode modulation(single-sideband modulation)based on an injection-locked semiconductor laser is a much simpler solution.In the uplink,direct modulation of optical heterodyning signal can be used to realize the down-conversion of uplink millimeter-wave signal,which simplifies the receiver structure at the centre office.In the wavelength division multiplexing millimeter-wave RoF duplex system,the wavelength reuse in both downlink and uplink can save the wavelength resource in the whole system,which improves its efficiency.展开更多
In this paper, based on the idea of finite element method, the initial parametric method in bending, problem of a beam is extended to analyse the bar-system structure by employing Dirac function and llcavisidc step fu...In this paper, based on the idea of finite element method, the initial parametric method in bending, problem of a beam is extended to analyse the bar-system structure by employing Dirac function and llcavisidc step function.Then a new method for analysing the internal forces and deformations of bar-system structure in space is suggested by improving the mixed method in statically indeterminate structure.The inferred process and obtained answer will be more succinct and accurate when the problem of internal forces and deformations of bar-system structure is analysed by using the new method provided in this paper.展开更多
The rootsystem structural characteristics of annual seedlings of Pinus koraiensis, Pinus sylvestris var. mongolica, Larix olgensis and Picea koraiensis were studied with the method of excavation at the nursery of Maoe...The rootsystem structural characteristics of annual seedlings of Pinus koraiensis, Pinus sylvestris var. mongolica, Larix olgensis and Picea koraiensis were studied with the method of excavation at the nursery of Maoershan Experimental station in the Antumn of 1992. The results showed that there were large differences in some ways, such as their root quantities,distributive depth and dense layers of root systems,etc.展开更多
A quantum-like model of gravitational system is introduced to explore the formation of the solar system structure. In this model, the chaos behavior of a large number of original nebular particles in a gravitational f...A quantum-like model of gravitational system is introduced to explore the formation of the solar system structure. In this model, the chaos behavior of a large number of original nebular particles in a gravitational field can be described in terms of the wave function satisfying formal Schr?dinger equation, in which the Planck constant is replaced by a constant on cosmic scale. Numerical calculation shows that the radial distribution density of the particles has the character of wave curves with decreasing amplitudes and elongating wavelengths. By means of this model, many questions of the solar system, such as the planetary distance, mass, energy, angular momentum, the distribution of satellites, the structure of the planetary rings, and the asteroid belt and the Kuiper belt etc., can be explained in reason. In addition, the abnormal rotations of Venus and Mercury can be naturally explained by means of the quantum-like model.展开更多
A new nonlinear optimization approach with discrete design variables based on linear estimation is proposed, in which the complex engineering structures optimization problems, such as 3-D space plate-system structures...A new nonlinear optimization approach with discrete design variables based on linear estimation is proposed, in which the complex engineering structures optimization problems, such as 3-D space plate-system structures optimization problems, can be solved. By avoided using point -by-point searching strategy, which is usually used in other discrete optimization algorithms, the times of function calculation is greatly reduced.展开更多
The testing of large structures is limited by high costs and long cycles, making scaling methods an attractive solution. However, the scaling process of elastic rings introduces complexities in multi-parameter geometr...The testing of large structures is limited by high costs and long cycles, making scaling methods an attractive solution. However, the scaling process of elastic rings introduces complexities in multi-parameter geometric distortions, leading to a diminution in the predictive accuracy of the distorted similitude. To address this challenge, this study formulates a novel set of scaling laws, tailored to account for the intricate geometric distortions associated with elastic rings. The proposed scaling laws are formulated based on the intrinsic deformation characteristics of elastic rings, rather than the traditional systemic governing equations. Numerical and experimental cases are conducted to assess the efficacy and precision of the proposed scaling laws, and the obtained results are compared with those achieved by traditional methods. The outcomes demonstrate that the scaling laws put forth by this study significantly enhance the predictive capabilities for deformations of elastic rings.展开更多
Human life is not determined by mechanical fatalism or a single material factor;instead,based on the dualistic ontology and active force mechanism in the Unified Complex Systems Theory(UCST),it can be actively designe...Human life is not determined by mechanical fatalism or a single material factor;instead,based on the dualistic ontology and active force mechanism in the Unified Complex Systems Theory(UCST),it can be actively designed under the guidance of mind,in accordance with causal laws,and through systematic interactions.This study integrates the dualistic ontology of UCST,as well as the cooperative mechanism of active force(Fa)and passive force(Fp).Furthermore,by incorporating Master Jiqun’s philosophy of“life design”and the practical principle of“destiny establishment and transformation”from The Four Lessons of Liaofan Yuan,it constructs a three-dimensional framework for life design encompassing the dimensions of science,philosophy,and practice.The significance of this research lies in breaking through the predicament of materialism in the AI(artificial intelligence)era,explaining the autonomy and initiative of life,providing feasible pathways for life design,and ultimately achieving the in-depth integration of scientific rationality and the wisdom of traditional Eastern culture.展开更多
The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering c...The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering can optimize the electrochemical performance of MnO_(2).Here,based on the metal-organic frameworks(MOFs)-derived method and electrochemical reconstruction,a coral-like MnO_(2)structure integrated with a functional nitrogen-doped carbon(NC)coating is designed for Na-SC application.The bioinspired coral-like structure captures numerous electrolyte ions and increases the Na+concentration on the electrode surface,which is beneficial for optimizing the Na+transport pathway and accelerating the electrode reaction kinetics.Moreover,the coral-like crosslinked structure effectively enhances the mechanical properties,enabling the maintenance of the structure of MnO_(2)-based electrodes during long-term operation.Furthermore,in/ex-situ characterizations are performed to elucidate the mechanism of lattice transformation during electrochemical phase reconstruction.Additionally,the theoretical calculation and simulation results reveal the ion/electron dynamics in the fabricated electrode.The prepared electrode demonstrates excellent capacitance storage ability(340.7 F g^(−1)at 0.5 A g^(−1))and cycling stability(85.1%capacitance retention after 10,000 cycles).The assembled hybrid device exhibits exceptional life-span(82.0%capacitance retention after 10,000 cycles)and exceptional energy density(36.5 Wh kg^(−1)).This study provides a reliable biomimetic morphology design strategy for MnO_(2)cathodes,paving the way for the fabrication of high-performance Na-SCs.展开更多
By applying the segmentation and composition principles of ecosystem,the structure and interface of earth ecosystem are fully elaborated,and corresponding model diagrams are established to display its composition and ...By applying the segmentation and composition principles of ecosystem,the structure and interface of earth ecosystem are fully elaborated,and corresponding model diagrams are established to display its composition and interconversion. The research finds that earth ecosystem includes three sub-ecosystems： terrestrial ecosystem,marine ecosystem and atmospheric ecosystem. The impact sequence of sub-ecosystems on earth ecosystem is atmospheric ecosystem 〉 marine ecosystem 〉 terrestrial ecosystem. Based on the segmentation and composition principles of ecosystem and the application of earth ecosystem structure and interface,we give new explanations to Taoism and Taiji with the eight diagrams,which contributes to theoretical research of natural science.展开更多
Marine pollution and overfishing induced the biodiversity loss and ecological degradation of the Beibu Gulf ecosystem in Guangxi,SE China.In an effort to restore the ecosystem and fishery resources,artificial reefs we...Marine pollution and overfishing induced the biodiversity loss and ecological degradation of the Beibu Gulf ecosystem in Guangxi,SE China.In an effort to restore the ecosystem and fishery resources,artificial reefs were deployed in the Beibu Gulf as the marine ranching area and their ecological performance need to be investigated.We constructed Ecopath ecological trophic models for the marine ranching area and a nearby control area to compare their ecosystem throughput and food web structure difference,and to calculate the ecological carrying capacity of various functional groups.Results indicate that the total system throughput of the marine ranching area was significantly higher than the control area,and the majority of system throughput occurred at trophic levelsⅠandⅡin both ecosystems.The system connectance indices for the marine ranching and control areas were 0.27 and 0.32,and the omnivory indices were 0.16 and 0.19,indicating simple food web structures;both areas are in a developmental stage with TPP/TR ratios of 2.69 and 9.36,respectively.Compared to the control area,marine ranching area exhibited a higher system maturity,and the ecological carrying capacity of“large and medium-sized demersal fish”and“other bivalves”functional groups in the marine ranching area increased by 43.83%and 233.62%,respectively,allowing for more high-trophic-level predators and large benthic animals.This study provided a reference for the formulation of fishery management policies in the Beibu Gulf,to maintain ecosystem stability and biodiversity.展开更多
Based on the generalized reduced R-matrix theory,the R-matrix analysis code(RAC program)was used to analyze the experimental data of all the nuclear reaction channels related to the 5 He system.The current calculation...Based on the generalized reduced R-matrix theory,the R-matrix analysis code(RAC program)was used to analyze the experimental data of all the nuclear reaction channels related to the 5 He system.The current calculations provide accurate and reliable evaluation data and are in good agreement with the experimental data.In this study,self-consistent evaluation data for each reaction were obtained using multi-channel and multi-energy fitting.In particular,the error propagation theory of generalized least squares was used to determine the error of the evaluation data and the covariance matrix of the integral cross section.This R-matrix analysis for the 5 He system has three features.First,for the first time,the error in the evaluation data of the T(d,n)^(4)He reaction cross section and the covariance matrix of the integral cross section are provided.Second,we used only one set of R-matrix parameters to depict the reaction cross section of each reaction channel of the 5 He system for the entire energy region in our work.Third,in this evaluation,we considered some of the latest measured experimental data,especially after 2000.The T(d,n)^(4)He reaction cross section at 0.1 MeV and below was carefully studied.The effect of different energy levels in T(d,n)^(4)He was analyzed,with the energy levels 3/2^(+)making a major contribution to the cross section,and the role of the S-wave and P-wave from 3/2~-determines the lean forward trend of the angular distributions at 0.01–0.1 MeV.展开更多
Arid and semi-arid ecosystems are prone to extensive fires due to specific climatic conditions,sparse vegetation cover,and high density of fine fuels.Understanding the flammability characteristics of land covers is es...Arid and semi-arid ecosystems are prone to extensive fires due to specific climatic conditions,sparse vegetation cover,and high density of fine fuels.Understanding the flammability characteristics of land covers is essential for fire management and designing land restoration programs in arid and semi-arid ecosystems.This study provided a new approach to evaluate the flammability of shrublands and woodlands using flammability indices(FIs)including time to ignition(TI),duration of combustion(DC),and flame height(FH)of plant species and their relative frequencies in the Dalfard Basin of southeastern Iran.The results showed that there was a significant difference in FIs between land covers.Shrublands had higher flammability potential compared with woodlands.Plant moisture content had a negative relationship with TI(P<0.010)and no significant relationship with DC and FH(P>0.050).Artemisia spp.,Astragalus gossypinus Fischer,Amygdalus scoparia Spach,and Cymbopogon jwarancusa(Jones)Schult.had the highest FI.Tree species such as Rhazya stricta Decne.,and Pistacia atlantica Desf.showed greater resistance to fire.Using principal component analysis,the relationship between species and FIs was examined,and TI of wet fuel was the most important FI in relation to species.Structural equation model showed that life form(P<0.001)was the most important flammability driver.Precipitation(P<0.010)and legume species(P<0.010)were significantly related to the flammability in arid land.This study emphasizes the importance of managing high-risk species and using resistant species in vegetation restoration and shows that combining species FIs with their abundance is an effective tool for assessing fire risk and fuel management at the plant community scale.展开更多
The complex chaotic behavior of a quasi-zero-stiffness(QZS)double-winged system with symmetric impact boundaries is investigated with Melnikov functions and numerical simulations.The analysis reveals the coexistence o...The complex chaotic behavior of a quasi-zero-stiffness(QZS)double-winged system with symmetric impact boundaries is investigated with Melnikov functions and numerical simulations.The analysis reveals the coexistence of multiple attractors.As a key mass parameter varies,the mechanism underlying degenerate singular closed orbits is elucidated,based upon which five distinct types of singular closed orbits are discovered,exhibiting both smooth and discontinuous(SD)characteristics.The chaotic threshold of each singular orbit is obtained by Melnikov functions and verified by numerical simulations.The numerical results further demonstrate the coexistence of SD motions.For zero damping systems,the Kolmogorov-Arnold-Moser(KAM)structures are exhibited to present the complex quasi-periodic and resonant behavior coexisting with chaotic and periodic motions.These findings advance the understanding of chaotic dynamics in nonsmooth multi-well impact systems.展开更多
The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and ...The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and fluid mobility due to the influences of the northeast and northwest dual provenance systems.This study performed multiple experimental analyses on nine samples from the area to determine the petrological and petrophysical properties,as well as the PTS characteristics of reservoirs in different provenance-controlled regions.On this basis,the pore-throat size distribution(PSD)obtained from high-pressure mercury injection(HPMI)was utilized to convert the NMR movable fluid T2spectrum,allowing for quantitative characterization of the full PSD and the occurrence characteristics of movable fluids.A systematic analysis was conducted on the primary controlling factors affecting fluid mobility in the reservoir.The results indicated that the lithology in the eastern and western regions is lithic arkose.The eastern sandstones,being farther from the provenance,exhibit higher contents of feldspar and lithic fragments,along with the development of more dissolution pores.The reservoir possesses good petrophysical properties,low displacement pressure,and high pore-throat connectivity and homogeneity,indicating strong fluid mobility.In contrast,the western sandstones,being nearer to the provenance,exhibit poor grain sorting,high contents of lithic fragments,strong compaction and cementation effects,resulting in poor petrophysical properties,and strong pore-throat heterogeneity,revealing weak fluid mobility.The range of full PSD in the eastern reservoir is wider than that in the western reservoir,with relatively well-developed macropores.The macropores are the primary space for occurrence of movable fluids,and controls the fluid mobility of the reservoir.The effective porosity of movable fluids(EPMF)quantitatively represents the pore space occupied by movable fluids within the reservoir and correlates well with porosity,permeability,and PTS parameters,making it a valuable parameter for evaluating fluid mobility.Under the multi-provenance system,the eastern and western reservoirs underwent different sedimentation and diagenesis processes,resulting in differential distribution of reservoir mineral components and pore types,which in turn affects the PTS heterogeneity and reservoir quality.The composition and content of reservoir minerals are intrinsic factors influencing fluid mobility,while the microscopic PTS is the primary factor controlling it.Low clay mineral content,welldeveloped macropores,and weak pore-throat heterogeneity all contribute to the storage and seepage of reservoir fluids.展开更多
Embodied intelligent systems integrate perception,control,and decision-making within physical agents,and have become a cornerstone of modern aerospace,autonomous driving,and cooperative robotic applications.When opera...Embodied intelligent systems integrate perception,control,and decision-making within physical agents,and have become a cornerstone of modern aerospace,autonomous driving,and cooperative robotic applications.When operating in uncertain and dynamic environments,such systems must address challenges arising from incomplete sensing,unpredictable maneuvers,communication constraints,disturbances,and evolving network structures.展开更多
It is shown by the the law of mass action in combination with the coexistence theory of slag structure that KMn n =NMno /(NFeo [%Mn] does not change with basicities and maintains constant at constant temperature; the...It is shown by the the law of mass action in combination with the coexistence theory of slag structure that KMn n =NMno /(NFeo [%Mn] does not change with basicities and maintains constant at constant temperature; the oxidizing capabilities of multicomponent slag systems containing CaO, MgO etc., can be expressed by NFe tO =NFeO + 6NFe2 O3 + 8NFe3O4; the desulfurizing capabilities of various basic oxides for multicomponent slag systems can be calculated by Ls=8(KCaSNCaO+KMgsNMgo +KFeSNFeO)∑n/[%O]; the dephosphorizing capabili- ties of CaO-MgO-FeO-FeO O3-P2 O5 as well as CaO-FeO-Fe2 O3-A12 O3-P2 O5 molten slags expressed respectively by Lpo=(%P2O5)/[P]2 = 141.94[%O]5∑nK00(1 + K5N2Cao + K6N3CaO + K7N4CaO + K8N2MgO + K9N3MgO + K10N3FeO + K11N4Feo); LPO=(%P2O5)/[P]2= 141.94[%O]5∑nK00(1 + K10N2CaO+ K11N3CaO+ K12N4CaO + K13N3FeO + K14N4FeO) have good agreement with practical values.展开更多
基金Supported by the National Natural Science Foundation of China(70503025)the Knowledge Innovation Project of Chinese Academy of Sci-ences(KZCX2-YW-305-2+3 种基金KSCX2-YW-N-039)the National Project of Scientific and Technical Supporting Programs(2006BAC08B032006BAC08B06)international cooperation program of science and technolo-gy ministry(2006DFB919201).~~
文摘The dynamic changes of land system in Huang - Huai - Hai Plain between 1988 and 2000 were researched in this paper. Spatial dominance econometric model was estabilished on 1 km cell to quantificafionally analyze the driving-force for the dynamic change mechanism of land system, such as natural, social and economic factors. The future dynamic changes of land system in Huang - Huai - Hai Plain on each 1 km cell during 2000 to 2020 were stimulated by combining the dynamic changes of land system on each 1 km cell with different situations. The research indicated that the dynamic changes of land system structure changed mainly from the cultivated areas to building areas and industrial areas, and forest areas increased during this period. Although the revolutions of land system structure were different during 2000 to 2020 with the different referrence standard, ecological protection and economic development, the primary dynamic changes of land system structure were that the increase of building land areas with the decline cuhivaled land areas and the increase of woodlands.
基金Supported by the Special Fund for Agro-scientific Research in the Public Interest (No. 200903005)the National Basic Research Program of China (973 Program) (Nos. 2011CB409805, 2010CB951204)+3 种基金the National Natural Science Foundation of China (No. 40976103)the Special Fund for the Basic R&D Program in the Central Non-profit Research Institutes (No. 2009-ts-10)the Taishan Scholar Program of Shandong Provincethe Yellow & Bohai Seas Scientific Observation and Experiment Station for Fishery Resources and Environment, Ministry of Agriculture
文摘The southem Yellow Sea is an important fishing ground, providing abundant fishery resources. However, overfishing and climate change have caused a decline in the resource and damaged the ecosystem. We developed an ecosystem model to analyze the trophic interactions and ecosystem structure and function to guide sustainable development of the ecosystem. Atrophic mass-balance model of the southern Yellow Sea during 2000-2001 was constructed using Ecopath with Ecosim software. We defined 22 important functional groups and studied their diet composition. The trophic levels of fish, shrimp, crabs, and cephalopods were between 2.78 and 4.39, and the mean trophic level of the fisheries was 3.24. The trophic flows within the food web occurred primarily in the lower trophic levels. The mean trophic transfer efficiency was 8.1%, of which 7.1% was from primary producers and 9.3% was from detritus within the ecosystem. The transfer efficiency between trophic levels II to III to IV to V to 〉V was 5.0%, 5.7%, 18.5%, and 19.7%-20.4%, respectively. Of the total flow, phytoplankton contributed 61% and detritus contributed 39%. Fishing is defined as a top predator within the ecosystem, and has a negative impact on most commercial species. Moreover, the ecosystem had a high gross efficiency of the fishery and a high value of primary production required to sustain the fishery. Together, our data suggest there is high fishing pressure in the southern Yellow Sea. Based on analysis of Odum＇s ecological parameters, this ecosystem was at an immature stage. Our results provide some insights into the structure and development of this ecosystem.
基金supported by the National Natural Science Foundation of China(61471391)the China Postdoctoral Science Foundation(2013M542541)
文摘Based on the cognitive radar concept and the basic connotation of cognitive skywave over-the-horizon radar（SWOTHR）, the system structure and information processingmechanism about cognitive SWOTHR are researched. Amongthem, the hybrid network system architecture which is thedistributed configuration combining with the centralized cognition and its soft/hardware framework with the sense-detectionintegration are proposed, and the information processing framebased on the lens principle and its information processing flowwith receive-transmit joint adaption are designed, which buildand parse the work law for cognition and its self feedback adjustment with the lens focus model and five stages informationprocessing sequence. After that, the system simulation andthe performance analysis and comparison are provided, whichinitially proves the rationality and advantages of the proposedideas. Finally, four important development ideas of futureSWOTHR toward ＂high frequency intelligence information processing system＂ are discussed, which are scene information fusion, dynamic reconfigurable system, hierarchical and modulardesign, and sustainable development. Then the conclusion thatthe cognitive SWOTHR can cause the performance improvement is gotten.
文摘Identifying the structure of protected mountain ecosystems is an important task for understanding conservation sustainability.The study area,the Firtina Valley,located in the Rize City on the Eastern Blacksea Coast,is one of the biological hotspots and a National Park of Turkey.In order to identify the structure of mountain ecosystems,we generated a GIS database for the main environmental parameters of the study area,including elevation,slope and aspect layers for topographic structure,10year mean values of Normalized Difference Vegetation Index(NDVI),data for vegetation structure,annual mean temperature and precipitation layers for climatic structure,main soil groups for soil structure and stream flow accumulation,stream flow length and stream order layers for hydrological structure.To identify the complex relations among environmental factors in the study area a data reduction method is applied with Principal Component Analysis(PCA).PCA is performed using data of 16 layers from Geographical Information Systems(GIS).PCA analysis reduced 16 dimensions into 5 dimensions containing 75%of the variation in all data.It is also revealed that the topographic structure,mainly altitude,dominates the ecosystems of the Firtina Valley,but it should be considered that the interactions of environmental factors in an ecosystem dynamics are very complex.The ecosystem structure is determined by the environmental factors direct or indirect effects on energy regulation of an ecosystem.Therefore the relationship between topographic elements and other abiotic-biotic elements in the Firtina Valley are important for environmental assessment and sustainability of a protected area,and these effects are explained in this study.
基金funded by the National Natural Science Foundation of China under Grant No.60736003by National High Technology Research and Development Program of China("863 program")under Grant No.2006AA01Z261
文摘Based on the seamless integration of broadband optical and wireless access networks,millimeter-wave Radio over Fiber(RoF)technology is considered to be a promising solution for the next generation access networks which will provide high capacity and flexibility with low cost.But due to its large cost to realize,the system architecture needs to be optimized.In the millimeter-wave optical generation part,optical heterodyning method can be introduced to generate a high-frequency millimeter-wave signal using a low-frequency signal source.And the system efficiency can be greatly improved based on injection-locking of a semiconductor laser.In the downlink,the transmission distance can be greatly enhanced using single-sideband modulation.And the single-mode modulation(single-sideband modulation)based on an injection-locked semiconductor laser is a much simpler solution.In the uplink,direct modulation of optical heterodyning signal can be used to realize the down-conversion of uplink millimeter-wave signal,which simplifies the receiver structure at the centre office.In the wavelength division multiplexing millimeter-wave RoF duplex system,the wavelength reuse in both downlink and uplink can save the wavelength resource in the whole system,which improves its efficiency.
文摘In this paper, based on the idea of finite element method, the initial parametric method in bending, problem of a beam is extended to analyse the bar-system structure by employing Dirac function and llcavisidc step function.Then a new method for analysing the internal forces and deformations of bar-system structure in space is suggested by improving the mixed method in statically indeterminate structure.The inferred process and obtained answer will be more succinct and accurate when the problem of internal forces and deformations of bar-system structure is analysed by using the new method provided in this paper.
文摘The rootsystem structural characteristics of annual seedlings of Pinus koraiensis, Pinus sylvestris var. mongolica, Larix olgensis and Picea koraiensis were studied with the method of excavation at the nursery of Maoershan Experimental station in the Antumn of 1992. The results showed that there were large differences in some ways, such as their root quantities,distributive depth and dense layers of root systems,etc.
文摘A quantum-like model of gravitational system is introduced to explore the formation of the solar system structure. In this model, the chaos behavior of a large number of original nebular particles in a gravitational field can be described in terms of the wave function satisfying formal Schr?dinger equation, in which the Planck constant is replaced by a constant on cosmic scale. Numerical calculation shows that the radial distribution density of the particles has the character of wave curves with decreasing amplitudes and elongating wavelengths. By means of this model, many questions of the solar system, such as the planetary distance, mass, energy, angular momentum, the distribution of satellites, the structure of the planetary rings, and the asteroid belt and the Kuiper belt etc., can be explained in reason. In addition, the abnormal rotations of Venus and Mercury can be naturally explained by means of the quantum-like model.
文摘A new nonlinear optimization approach with discrete design variables based on linear estimation is proposed, in which the complex engineering structures optimization problems, such as 3-D space plate-system structures optimization problems, can be solved. By avoided using point -by-point searching strategy, which is usually used in other discrete optimization algorithms, the times of function calculation is greatly reduced.
基金Project supported by the National Natural Science Foundation of China(Nos.52405095,12272089,and 92360305)the Guangdong Basic and Applied Basic Research Foundation of China(No.2023A1515110557)+4 种基金the Natural Science Foundation of Liaoning Province of China(No.2023-BSBA-102)the Open Fund of National Key Laboratory of Particle Transport and Separation Technology of China(No.WZKF-2024-6)the Open Project of Guangxi Key Laboratory of Automobile Components and Vehicle Technology of China(Nos.2024GKLACVTKF07 and 2024GKLACVTKF06)the Basic Research Projects of Liaoning Provincial Department of Education of China(No.JYTQN2023162)the Fundamental Research Funds for the Central Universities of China(No.N2403022)。
文摘The testing of large structures is limited by high costs and long cycles, making scaling methods an attractive solution. However, the scaling process of elastic rings introduces complexities in multi-parameter geometric distortions, leading to a diminution in the predictive accuracy of the distorted similitude. To address this challenge, this study formulates a novel set of scaling laws, tailored to account for the intricate geometric distortions associated with elastic rings. The proposed scaling laws are formulated based on the intrinsic deformation characteristics of elastic rings, rather than the traditional systemic governing equations. Numerical and experimental cases are conducted to assess the efficacy and precision of the proposed scaling laws, and the obtained results are compared with those achieved by traditional methods. The outcomes demonstrate that the scaling laws put forth by this study significantly enhance the predictive capabilities for deformations of elastic rings.
基金supported by the start-up funding from Westlake University under Grant Number 041030150118 and the scientific research project of Westlake University“Theoretical Research and Demonstration Application of Complex Systems and Deep-Sea Technology(Phase I)”under Grant Number WU2025A006.
文摘Human life is not determined by mechanical fatalism or a single material factor;instead,based on the dualistic ontology and active force mechanism in the Unified Complex Systems Theory(UCST),it can be actively designed under the guidance of mind,in accordance with causal laws,and through systematic interactions.This study integrates the dualistic ontology of UCST,as well as the cooperative mechanism of active force(Fa)and passive force(Fp).Furthermore,by incorporating Master Jiqun’s philosophy of“life design”and the practical principle of“destiny establishment and transformation”from The Four Lessons of Liaofan Yuan,it constructs a three-dimensional framework for life design encompassing the dimensions of science,philosophy,and practice.The significance of this research lies in breaking through the predicament of materialism in the AI(artificial intelligence)era,explaining the autonomy and initiative of life,providing feasible pathways for life design,and ultimately achieving the in-depth integration of scientific rationality and the wisdom of traditional Eastern culture.
基金supported by the National Natural Science Foundation of China(22409065)the Guangdong Basic and Applied Basic Research Foundation(2022A1515011906)+2 种基金the China Postdoctoral Science Foundation(2023M731153)the Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technologythe Postdoctoral Fellowship Program of CPSF(GZC20230868).
文摘The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering can optimize the electrochemical performance of MnO_(2).Here,based on the metal-organic frameworks(MOFs)-derived method and electrochemical reconstruction,a coral-like MnO_(2)structure integrated with a functional nitrogen-doped carbon(NC)coating is designed for Na-SC application.The bioinspired coral-like structure captures numerous electrolyte ions and increases the Na+concentration on the electrode surface,which is beneficial for optimizing the Na+transport pathway and accelerating the electrode reaction kinetics.Moreover,the coral-like crosslinked structure effectively enhances the mechanical properties,enabling the maintenance of the structure of MnO_(2)-based electrodes during long-term operation.Furthermore,in/ex-situ characterizations are performed to elucidate the mechanism of lattice transformation during electrochemical phase reconstruction.Additionally,the theoretical calculation and simulation results reveal the ion/electron dynamics in the fabricated electrode.The prepared electrode demonstrates excellent capacitance storage ability(340.7 F g^(−1)at 0.5 A g^(−1))and cycling stability(85.1%capacitance retention after 10,000 cycles).The assembled hybrid device exhibits exceptional life-span(82.0%capacitance retention after 10,000 cycles)and exceptional energy density(36.5 Wh kg^(−1)).This study provides a reliable biomimetic morphology design strategy for MnO_(2)cathodes,paving the way for the fabrication of high-performance Na-SCs.
基金Supported by Education Ministry's New Century Excellent Talents Supporting Plan(NCET-12-0659)Project of Outstanding Technological Educators of Governor of Guizhou([2012]71)+3 种基金Project of Low Carbon Technology Plan of Guiyang(2012205)Project of Science and Technology Foundation of Guiyang(LKM[2012]05)Special Research Projects of High Level Talents of Guizhou Province(TZJF-2011-44)Research Projects of Guizhou Minzu University([2014]02)
文摘By applying the segmentation and composition principles of ecosystem,the structure and interface of earth ecosystem are fully elaborated,and corresponding model diagrams are established to display its composition and interconversion. The research finds that earth ecosystem includes three sub-ecosystems： terrestrial ecosystem,marine ecosystem and atmospheric ecosystem. The impact sequence of sub-ecosystems on earth ecosystem is atmospheric ecosystem 〉 marine ecosystem 〉 terrestrial ecosystem. Based on the segmentation and composition principles of ecosystem and the application of earth ecosystem structure and interface,we give new explanations to Taoism and Taiji with the eight diagrams,which contributes to theoretical research of natural science.
基金Supported by the National Key R&D Program of China(No.2022YFD2401301)the Primary Research and Development Plan of Guangxi Province(No.GuiKe AB21220064)+1 种基金the National Natural Science Foundation of China(Nos.42106102,42306151)the Shandong Postdoctoral Science Foundation(No.SDCXZG202301009)。
文摘Marine pollution and overfishing induced the biodiversity loss and ecological degradation of the Beibu Gulf ecosystem in Guangxi,SE China.In an effort to restore the ecosystem and fishery resources,artificial reefs were deployed in the Beibu Gulf as the marine ranching area and their ecological performance need to be investigated.We constructed Ecopath ecological trophic models for the marine ranching area and a nearby control area to compare their ecosystem throughput and food web structure difference,and to calculate the ecological carrying capacity of various functional groups.Results indicate that the total system throughput of the marine ranching area was significantly higher than the control area,and the majority of system throughput occurred at trophic levelsⅠandⅡin both ecosystems.The system connectance indices for the marine ranching and control areas were 0.27 and 0.32,and the omnivory indices were 0.16 and 0.19,indicating simple food web structures;both areas are in a developmental stage with TPP/TR ratios of 2.69 and 9.36,respectively.Compared to the control area,marine ranching area exhibited a higher system maturity,and the ecological carrying capacity of“large and medium-sized demersal fish”and“other bivalves”functional groups in the marine ranching area increased by 43.83%and 233.62%,respectively,allowing for more high-trophic-level predators and large benthic animals.This study provided a reference for the formulation of fishery management policies in the Beibu Gulf,to maintain ecosystem stability and biodiversity.
基金supported by Science Challenge Project(No.TZ20180001)。
文摘Based on the generalized reduced R-matrix theory,the R-matrix analysis code(RAC program)was used to analyze the experimental data of all the nuclear reaction channels related to the 5 He system.The current calculations provide accurate and reliable evaluation data and are in good agreement with the experimental data.In this study,self-consistent evaluation data for each reaction were obtained using multi-channel and multi-energy fitting.In particular,the error propagation theory of generalized least squares was used to determine the error of the evaluation data and the covariance matrix of the integral cross section.This R-matrix analysis for the 5 He system has three features.First,for the first time,the error in the evaluation data of the T(d,n)^(4)He reaction cross section and the covariance matrix of the integral cross section are provided.Second,we used only one set of R-matrix parameters to depict the reaction cross section of each reaction channel of the 5 He system for the entire energy region in our work.Third,in this evaluation,we considered some of the latest measured experimental data,especially after 2000.The T(d,n)^(4)He reaction cross section at 0.1 MeV and below was carefully studied.The effect of different energy levels in T(d,n)^(4)He was analyzed,with the energy levels 3/2^(+)making a major contribution to the cross section,and the role of the S-wave and P-wave from 3/2~-determines the lean forward trend of the angular distributions at 0.01–0.1 MeV.
文摘Arid and semi-arid ecosystems are prone to extensive fires due to specific climatic conditions,sparse vegetation cover,and high density of fine fuels.Understanding the flammability characteristics of land covers is essential for fire management and designing land restoration programs in arid and semi-arid ecosystems.This study provided a new approach to evaluate the flammability of shrublands and woodlands using flammability indices(FIs)including time to ignition(TI),duration of combustion(DC),and flame height(FH)of plant species and their relative frequencies in the Dalfard Basin of southeastern Iran.The results showed that there was a significant difference in FIs between land covers.Shrublands had higher flammability potential compared with woodlands.Plant moisture content had a negative relationship with TI(P<0.010)and no significant relationship with DC and FH(P>0.050).Artemisia spp.,Astragalus gossypinus Fischer,Amygdalus scoparia Spach,and Cymbopogon jwarancusa(Jones)Schult.had the highest FI.Tree species such as Rhazya stricta Decne.,and Pistacia atlantica Desf.showed greater resistance to fire.Using principal component analysis,the relationship between species and FIs was examined,and TI of wet fuel was the most important FI in relation to species.Structural equation model showed that life form(P<0.001)was the most important flammability driver.Precipitation(P<0.010)and legume species(P<0.010)were significantly related to the flammability in arid land.This study emphasizes the importance of managing high-risk species and using resistant species in vegetation restoration and shows that combining species FIs with their abundance is an effective tool for assessing fire risk and fuel management at the plant community scale.
基金Project supported by the National Natural Science Foundation of China(No.11732006)the China Scholarship Council。
文摘The complex chaotic behavior of a quasi-zero-stiffness(QZS)double-winged system with symmetric impact boundaries is investigated with Melnikov functions and numerical simulations.The analysis reveals the coexistence of multiple attractors.As a key mass parameter varies,the mechanism underlying degenerate singular closed orbits is elucidated,based upon which five distinct types of singular closed orbits are discovered,exhibiting both smooth and discontinuous(SD)characteristics.The chaotic threshold of each singular orbit is obtained by Melnikov functions and verified by numerical simulations.The numerical results further demonstrate the coexistence of SD motions.For zero damping systems,the Kolmogorov-Arnold-Moser(KAM)structures are exhibited to present the complex quasi-periodic and resonant behavior coexisting with chaotic and periodic motions.These findings advance the understanding of chaotic dynamics in nonsmooth multi-well impact systems.
文摘The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and fluid mobility due to the influences of the northeast and northwest dual provenance systems.This study performed multiple experimental analyses on nine samples from the area to determine the petrological and petrophysical properties,as well as the PTS characteristics of reservoirs in different provenance-controlled regions.On this basis,the pore-throat size distribution(PSD)obtained from high-pressure mercury injection(HPMI)was utilized to convert the NMR movable fluid T2spectrum,allowing for quantitative characterization of the full PSD and the occurrence characteristics of movable fluids.A systematic analysis was conducted on the primary controlling factors affecting fluid mobility in the reservoir.The results indicated that the lithology in the eastern and western regions is lithic arkose.The eastern sandstones,being farther from the provenance,exhibit higher contents of feldspar and lithic fragments,along with the development of more dissolution pores.The reservoir possesses good petrophysical properties,low displacement pressure,and high pore-throat connectivity and homogeneity,indicating strong fluid mobility.In contrast,the western sandstones,being nearer to the provenance,exhibit poor grain sorting,high contents of lithic fragments,strong compaction and cementation effects,resulting in poor petrophysical properties,and strong pore-throat heterogeneity,revealing weak fluid mobility.The range of full PSD in the eastern reservoir is wider than that in the western reservoir,with relatively well-developed macropores.The macropores are the primary space for occurrence of movable fluids,and controls the fluid mobility of the reservoir.The effective porosity of movable fluids(EPMF)quantitatively represents the pore space occupied by movable fluids within the reservoir and correlates well with porosity,permeability,and PTS parameters,making it a valuable parameter for evaluating fluid mobility.Under the multi-provenance system,the eastern and western reservoirs underwent different sedimentation and diagenesis processes,resulting in differential distribution of reservoir mineral components and pore types,which in turn affects the PTS heterogeneity and reservoir quality.The composition and content of reservoir minerals are intrinsic factors influencing fluid mobility,while the microscopic PTS is the primary factor controlling it.Low clay mineral content,welldeveloped macropores,and weak pore-throat heterogeneity all contribute to the storage and seepage of reservoir fluids.
文摘Embodied intelligent systems integrate perception,control,and decision-making within physical agents,and have become a cornerstone of modern aerospace,autonomous driving,and cooperative robotic applications.When operating in uncertain and dynamic environments,such systems must address challenges arising from incomplete sensing,unpredictable maneuvers,communication constraints,disturbances,and evolving network structures.
文摘It is shown by the the law of mass action in combination with the coexistence theory of slag structure that KMn n =NMno /(NFeo [%Mn] does not change with basicities and maintains constant at constant temperature; the oxidizing capabilities of multicomponent slag systems containing CaO, MgO etc., can be expressed by NFe tO =NFeO + 6NFe2 O3 + 8NFe3O4; the desulfurizing capabilities of various basic oxides for multicomponent slag systems can be calculated by Ls=8(KCaSNCaO+KMgsNMgo +KFeSNFeO)∑n/[%O]; the dephosphorizing capabili- ties of CaO-MgO-FeO-FeO O3-P2 O5 as well as CaO-FeO-Fe2 O3-A12 O3-P2 O5 molten slags expressed respectively by Lpo=(%P2O5)/[P]2 = 141.94[%O]5∑nK00(1 + K5N2Cao + K6N3CaO + K7N4CaO + K8N2MgO + K9N3MgO + K10N3FeO + K11N4Feo); LPO=(%P2O5)/[P]2= 141.94[%O]5∑nK00(1 + K10N2CaO+ K11N3CaO+ K12N4CaO + K13N3FeO + K14N4FeO) have good agreement with practical values.
