Aim To present a quantitative method for structural complexity analysis and evaluation of information systems. Methods Based on Petri net modeling and analysis techniques and with the aid of mathematical tools in ge...Aim To present a quantitative method for structural complexity analysis and evaluation of information systems. Methods Based on Petri net modeling and analysis techniques and with the aid of mathematical tools in general net theory(GNT), a quantitative method for structure description and analysis of information systems was introduced. Results The structural complexity index and two related factors, i.e. element complexity factor and connection complexity factor were defined, and the relations between them and the parameters of the Petri net based model of the system were derived. Application example was presented. Conclusion The proposed method provides a theoretical basis for quantitative analysis and evaluation of the structural complexity and can be applied in the general planning and design processes of the information systems.展开更多
The suprachiasmatic nucleus in the hypothalamus is the master circadian clock in mammals,coordinating physiological processes with the 24-hour day–night cycle.Comprising various cell types,the suprachiasmatic nucleus...The suprachiasmatic nucleus in the hypothalamus is the master circadian clock in mammals,coordinating physiological processes with the 24-hour day–night cycle.Comprising various cell types,the suprachiasmatic nucleus(SCN)integrates environmental signals to maintain complex and robust circadian rhythms.Understanding the complexity and synchrony within SCN neurons is essential for effective circadian clock function.Synchrony involves coordinated neuronal firing for robust rhythms,while complexity reflects diverse activity patterns and interactions,indicating adaptability.Interestingly,the SCN retains circadian rhythms in vitro,demonstrating intrinsic rhythmicity.This study introduces the multiscale structural complexity method to analyze changes in SCN neuronal activity and complexity at macro and micro levels,based on Bagrov et al.’s approach.By examining structural complexity and local complexities across scales,we aim to understand how tetrodotoxin,a neurotoxin that inhibits action potentials,affects SCN neurons.Our method captures critical scales in neuronal interactions that traditional methods may overlook.Validation with the Goodwin model confirms the reliability of our observations.By integrating experimental data with theoretical models,this study provides new insights into the effects of tetrodotoxin(TTX)on neuronal complexities,contributing to the understanding of circadian rhythms.展开更多
The inclusion complex of β-cyclodextrin with m-nitrophenoxyacetic acid was studied by single crystal X-ray diffraction,2D NMR spectroscopy and semi-empirical methods AMI.The crystallographic study shows that two β-c...The inclusion complex of β-cyclodextrin with m-nitrophenoxyacetic acid was studied by single crystal X-ray diffraction,2D NMR spectroscopy and semi-empirical methods AMI.The crystallographic study shows that two β-cyclodextrins are held together by hydrogen bonds to form head-to-head dimers.The disordered vip molecule adjusts itself to attain the most stable accommodation into the cavity in which the nitro group is located at the dimer interface while the carboxyl group is buried in the primary hydroxyl groups of β-cyclodextrin.The vip inside the cavity is disordered over two sites and exhibits mobility.Moreover,2D NMR spectroscopy and theoretical study show the same inclusion behavior.In comparison to the inclusion complex of β-cyclodextrin with p-nitrophenoxyacetic acid,the host-vip stoichiometries are different,i.e.,2：1 for m-nitrophenoxyacetic acid and 1：1 for p-nitrophenoxyacetic acid,while the inclusion orientation and the packing pattern of the host are similar in both complexes.展开更多
Marine shale gas in the southern Sichuan Basin is the most successful area of shale gas exploration and development in China.In order to open up new shale gas fields and search for new shale gas reserves and productio...Marine shale gas in the southern Sichuan Basin is the most successful area of shale gas exploration and development in China.In order to open up new shale gas fields and search for new shale gas reserves and production replacement blocks,it is necessary to continuously establish and complete the standards on shale gas reservoir evaluation and area selection under different structural settings.The early exploration practice shows that shale in the mountainous complex structural area along the southwestern margin of the Sichuan Basin varies greatly in the gas bearing property,so systematical analysis and study on the shale gas enrichment mechanisms in this area is of great significance to searching for new shale gas exploration areas.Based on drilling data of 5 wells in the mountainous complex structural area along the southwestern margin of the Sichuan Basin,the main factors controlling the shale gas bearing property and the shale gas enrichment model were discussed based on the systematical experiments and analysis of the outcrops,cores and cuttings of Longmaxi Formation shale from the aspects of organic geochemistry,physical property,gas content,hydrocarbon generation history and pore evolution history,so as to lay a solid geological basis for the birth of a new shale gas area.And the following research results were obtained.First,the shale of the first submember of first Member of Longmaxi Formation(S1l11)in the mountainous complex structural area along the southwestern margin of the Sichuan Basin has an average TOC of 3.02%–4.97%and Ro of 2.38%–3.37%,and the average total gas content in local enrichment zones is up to 4.62 m^(3)/t,so it is classified as quality shale.Second,the detailed studies on hydrocarbon generation history indicate that the shale has the characteristics of“low thermal evolution rate and low maturity”.It is characterized by late hydrocarbon generation,low thermal evolution rate,low current maturity and short late diffusion time,which are favorable for shale gas enrichment.Third,the pore evolution history reveals that shale pore evolution can be divided into six stages,i.e.,sharp pore reduction,pore reduction,organic pore formation,pore preservation,organic pore dissipation and karstification,and organic pore and TOC are the most direct control factors of shale gas content.Fourth,favorable shelf facies belt is conducive to the formation of large-scale reservoir space and effective pores,and diversities of preservation conditions under different structural styles and at different structural positions control different pore evolution stages.The shale gas in the mountainous complex structural area is characterized by horizontal zoning and differential enrichment.“Low thermal evolution rate and low maturity”and“slow structural uplifting”are beneficial to the long-term enrichment and preservation of shale gas.In conclusion,the mountainous complex structural area along the southwestern margin of the Sichuan Basin has a shale gas enrichment model of“sedimentation controlling source rocks,diagenesis controlling reservoirs and structure controlling preservation”.This research result provides idea and reference for searching for new shale gas areas and fields.展开更多
The horizontal distribution of stems, stand density and the differentiation of tree dimensions are among the most important aspects of stand structure. An increasing complexity of stand structure is often linked to a ...The horizontal distribution of stems, stand density and the differentiation of tree dimensions are among the most important aspects of stand structure. An increasing complexity of stand structure is often linked to a higher number of species and to greater ecological stability. For quantification, the Structural Complexity Index (SCI) describes structural complexity by means of an area ratio of the surface that is generated by connecting the tree tops of neighbouring trees to form triangles to the surface that is covered by all triangles if projected on a flat plane. Here, we propose two ecologically relevant modifications of the SCI: The degree of mingling of tree attributes, quantified by a vector ruggedness measure, and a stem density term. We investigate how these two modifications influence index values. Data come from forest inventory field plots sampled along a disturbance gradient from heavily disturbed shrub land, through secondary regrowth to mature montane rainforest stands in Mengsong, Xishuangbanna,Yunnan,China. An application is described linking structural complexity, as described by the SCI and its modified versions, to changes in species composition of insect communities. The results of this study show that the Enhanced Structural Complexity Index (ESCI) can serve as a valuable tool for forest managers and ecologists for describing the structural complexity of forest stands and is particularly valuable for natural forests with a high degree of structural complexity.展开更多
Beethoven is a famous German pianist, composer, and conductor, and he set the culmination of Western classical, created a romantic music camp precedent. The size of his music in general is very ambitious, mostly conce...Beethoven is a famous German pianist, composer, and conductor, and he set the culmination of Western classical, created a romantic music camp precedent. The size of his music in general is very ambitious, mostly concertos, symphonies, operas and other large works, technical approach and structure used is quite complex, people are left with a deep impression. But it works, while small piano pieces, also has music research value, ＂dedicated to Alice＂ is one of the few Beethoven piano pieces. This paper focuses on creative background ＂dedicated to Alice,＂ this elaborate piano works by the complexity of the analysis of the structure of this work is that it reflects the author＇ s ideological soul to explore their musical value.展开更多
The Reliability-Based Design Optimization(RBDO)of complex engineering structures considering uncertainties has problems of being high-dimensional,highly nonlinear,and timeconsuming,which requires a significant amount ...The Reliability-Based Design Optimization(RBDO)of complex engineering structures considering uncertainties has problems of being high-dimensional,highly nonlinear,and timeconsuming,which requires a significant amount of sampling simulation computation.In this paper,a basis-adaptive Polynomial Chaos(PC)-Kriging surrogate model is proposed,in order to relieve the computational burden and enhance the predictive accuracy of a metamodel.The active learning basis-adaptive PC-Kriging model is combined with a quantile-based RBDO framework.Finally,five engineering cases have been implemented,including a benchmark RBDO problem,three high-dimensional explicit problems,and a high-dimensional implicit problem.Compared with Support Vector Regression(SVR),Kriging,and polynomial chaos expansion models,results show that the proposed basis-adaptive PC-Kriging model is more accurate and efficient for RBDO problems of complex engineering structures.展开更多
Forest structural complexity influences arthropod communities by shaping habitat availability,microclimatic conditions,and resource distribution.However,the extent to which structural complexity and specific structura...Forest structural complexity influences arthropod communities by shaping habitat availability,microclimatic conditions,and resource distribution.However,the extent to which structural complexity and specific structural components drive arthropod abundance and biomass remains poorly understood in temperate forests.This study examined how local and landscape-scale forest characteristics influence arthropod communities across vertical strata(forest floor(FF),herb layer(HL),and shrub layer(SL))in 19 temperate deciduous forests in Belgium,dominated by pedunculate oak,European beech,or Canadian poplar.At the local scale,we assessed dominant tree species identity,overall forest structural complexity,and its components(vertical and horizontal structure,woody layer,herbal layer,and deadwood).At the landscape scale,we evaluated forest area,edge length,forest cover,and vegetation greenness(normalized difference vegetation index(NDVI)).Contrary to expectation,arthropod biomass and abundance did not consistently increase with higher structural complexity.Instead,woody layer complexity,dominant tree species,and NDVI emerged as key drivers,with effects varying by context and stratum.Arthropod abundance and biomass were the highest in oak-and poplar-dominated forests and the lowest in beech forests,likely due to differences in litter quality,microhabitat availability,and understory development.Woody layer complexity positively influenced forest floor arthropods in poplar forests but had a negative effect in oak forests.At the landscape scale,NDVI unexpectedly showed negative relationships with arthropod abundance across strata and with arthropod biomass in the herb layer,likely reflecting dense canopy suppression of understory productivity.Arthropod biomass on the forest floor increased with forest cover,while abundance in the shrub layer decreased with forest cover but increased with forest area.These findings highlight the complex interplay between forest structural attributes,dominant tree species,and landscape factors in shaping arthropod communities.By identifying the key drivers of arthropod abundance and biomass,this study contributes to a better understanding of biodiversity patterns in temperate forests and their ecological dynamics.展开更多
Electrochemical micromachining （EMM） technology for fabricating micro structures is presented in this article. By applying ultra short pulses, dissolution of a workpiece can be restricted to the region very close to...Electrochemical micromachining （EMM） technology for fabricating micro structures is presented in this article. By applying ultra short pulses, dissolution of a workpiece can be restricted to the region very close to the electrode. First, an EMM system for meeting the requirements of the EMM process is established. Second, sets of experiments is carried out to investigate the influence of some of the predominant electrochemical process parameters such as electrical parameters, feed rate, electrode geometry features and electrolyte composition on machining quality, especially the influences of pulse on time on shape precision and working end shape of electrode on machined surface quality. Finally, after the preliminary experiments, a complex microstructure with good shape precision and surface quality is successfully obtained.展开更多
Large-scale 3D physical models of complex structures can be used to simulate hydrocarbon exploration areas. The high-fidelity simulation of actual structures poses challenges to model building and quality control. Suc...Large-scale 3D physical models of complex structures can be used to simulate hydrocarbon exploration areas. The high-fidelity simulation of actual structures poses challenges to model building and quality control. Such models can be used to collect wideazimuth, multi-azimuth, and full-azimuth seismic data that can be used to verify various 3D processing and interpretation methods. Faced with nonideal imaging problems owing to the extensive complex surface conditions and subsurface structures in the oil-rich foreland basins of western China, we designed and built the KS physical model based on the complex subsurface structure. This is the largest and most complex 3D physical model built to date. The physical modeling technology advancements mainly involve 1） the model design method, 2） the model casting flow, and 3） data acquisition. A 3D velocity model of the physical model was obtained for the first time, and the model building precision was quantitatively analyzed. The absolute error was less than 3 mm, which satisfies the experimental requirements. The 3D velocity model obtained from 3D measurements of the model layers is the basis for testing various imaging methods. Furthermore, the model is considered a standard in seismic physical modeling technology.展开更多
Electromagnetic logging while drilling(LWD)is one of the key technologies of the geosteering and formation evaluation for high-angle and horizontal wells.In this paper,we solve the dipole source-generated magnetic/ele...Electromagnetic logging while drilling(LWD)is one of the key technologies of the geosteering and formation evaluation for high-angle and horizontal wells.In this paper,we solve the dipole source-generated magnetic/electric fields in 2D formations efficiently by the 2.5D finite diff erence method.Particularly,by leveraging the field’s rapid attenuation in spectral domain,we propose truncated Gauss–Hermite quadrature,which is several tens of times faster than traditional inverse fast Fourier transform.By applying the algorithm to the LWD modeling under complex formations,e.g.,folds,fault and sandstone pinch-outs,we analyze the feasibility of the dimension reduction from 2D to 1D.For the formations with smooth lateral changes,like folds,the simplified 1D model’s results agree well with the true responses,which indicate that the 1D simplification with sliding window is feasible.However,for the formation structures with drastic rock properties changes and sharp boundaries,for instance,faults and sandstone pinch-outs,the simplified 1D model will lead to large errors and,therefore,2.5D algorithms should be applied to ensure the accuracy.展开更多
Simulation for stochastic wind field is very important in analyzing dynamic responses of large complex structures due to strong wind.The typical simulation method is the spectrum representation method (SRM),but the SR...Simulation for stochastic wind field is very important in analyzing dynamic responses of large complex structures due to strong wind.The typical simulation method is the spectrum representation method (SRM),but the SRM has drawbacks of inferior precision in lower frequency and slow calculating speed.In view of this,the modified Fourier spectrum method (MFSM) is introduced into the simulation of stochastic wind field in this paper.In this method,phase information of wind velocity time history is determined by cross power spectral density (CPSD) between adjacent points,and the wind velocity time history with time and space correlation is generated by iterative modification for CPSD considering auto power spectral density (APSD).Simulation of the wind field for a long-span bridge is undertaken to verify the effectiveness of the MFSM.Simulation results of the SRM and the MFSM are compared.It can be concluded that the MFSM is more accurate and has higher calculation speed than the SRM.展开更多
To provide system designer a valid measure to evaluate the structure complexityof class diagrams objectively, this letter first proposes a method to transform a class diagramsinto a weighted class dependence graph, th...To provide system designer a valid measure to evaluate the structure complexityof class diagrams objectively, this letter first proposes a method to transform a class diagramsinto a weighted class dependence graph, then presents a structure complexity measure for classdiagrams based on entropy distance.展开更多
In this paper, the X-ray nondestructive test method of small defects in precision weldments with complex structure was presented. To resolve the difficulty of defect segmentation in variable grey image, the image proc...In this paper, the X-ray nondestructive test method of small defects in precision weldments with complex structure was presented. To resolve the difficulty of defect segmentation in variable grey image, the image processing based on Visual Basic programming method was adopted. The methods of automatic contrast and partial grey stretch were used to enhance the X-ray detection image which has relatively low contrast, then automatic threshold method was carried out to segment the two high intensity zones, and weld zones which contain the small defects was extracted. Smoothing and sharpen processing were proceeded on the extracted weld zones, and small defects in X-ray detection image of weldments with complex structure were segmented by using the method of background subtraction in the end. The effects of raster were eliminated, and because of that the image processing was only proceeded on the extracted weld zones, the calculated speed using the above provided algorithm was improved.展开更多
The main purpose of this note is to construct almost complex or complex structures on certain isoparametric hypersurfaces in unit spheres.As a consequence,complex structures on S^(1)×S^(7)×S^(6),and on S^(10...The main purpose of this note is to construct almost complex or complex structures on certain isoparametric hypersurfaces in unit spheres.As a consequence,complex structures on S^(1)×S^(7)×S^(6),and on S^(10)×S^(3)×S(2)with vanishing first Chern class,are built.展开更多
Inclusion compound of retinoic acid with (-cyclodextrin was prepared by coprecipitating method, the structure of resulting product was studied by elemental analysis, differential scanning caloriemetry(DSC) analysis, F...Inclusion compound of retinoic acid with (-cyclodextrin was prepared by coprecipitating method, the structure of resulting product was studied by elemental analysis, differential scanning caloriemetry(DSC) analysis, FT-IR spectroscopy and X-ray diffractometry, and the formed supramolecule self-assembles in aqueous solution according to molar ratio 2:1 of host-vip.展开更多
One complex with a zwitterionic dicarboxylate ligand, [Mn（L）（N3）]n 1 （L = 1-car- boxymethylpyridinium-3-carboxylate）, was synthesized and structurally characterized. Complex 1 crystallizes in triclinic, space gr...One complex with a zwitterionic dicarboxylate ligand, [Mn（L）（N3）]n 1 （L = 1-car- boxymethylpyridinium-3-carboxylate）, was synthesized and structurally characterized. Complex 1 crystallizes in triclinic, space group P1 with a = 7.570（2）, b = 7.808（2）, c = 9.232（3） A, β= 94.450（19）°, V= 489.0（3） A3, Z = 2, Mr = 277.11, Dc = 1.882 g/cm3, F（000） = 278,μ = 1.359 mm-1, S = 1.021, the final R = 0.0509 and wR = 0.1149 for 2236 observed reflections with 1 〉 2σ（I）. Complex 1 consists of two-dimensional coordination layers in which the anionic uniform chains with mixed triple bridges （one end-on （EO） azide and two syn-syn carboxylates） are cross-linked by the flexible cationic N-methylpyridinium spacers. Magnetic studies demonstrated that the triple bridge in 1 transmits antiferromagnetic coupling between the Mn（Ⅱ） ions.展开更多
Accurately solving transient nonlinear inverse heat conduction problems in complex structures is of great importance to provide key parameters for modeling coupled heat transfer process and the structure’s optimizati...Accurately solving transient nonlinear inverse heat conduction problems in complex structures is of great importance to provide key parameters for modeling coupled heat transfer process and the structure’s optimization design.The finite element method in ABAQUS is employed to solve the direct transient nonlinear heat conduction problem.Improved particle swarm optimization(PSO)method is developed and used to solve the transient nonlinear inverse problem.To investigate the inverse performances,some numerical tests are provided.Boundary conditions at inaccessible surfaces of a scramjet combustor with the regenerative cooling system are inversely identified.The results show that the new methodology can accurately and efficiently determine the boundary conditions in the scramjet combustor with the regenerative cooling system.By solving the transient nonlinear inverse problem,the improved particle swarm optimization for solving the transient nonlinear inverse heat conduction problem in a complex structure is verified.展开更多
Two 1D coordination polymers[Ln2(dpdc)3(tpy)2·H2O]n[Ln=Nd 1,Yb 2,H2dpdc=2,2'-biphenyldicarboxylic acid and tpy=2,2':6',2''-terpyridine]and one dinuclear complex Er2(dpdc)2(Hdpdc)2(tpy)23 were ...Two 1D coordination polymers[Ln2(dpdc)3(tpy)2·H2O]n[Ln=Nd 1,Yb 2,H2dpdc=2,2'-biphenyldicarboxylic acid and tpy=2,2':6',2''-terpyridine]and one dinuclear complex Er2(dpdc)2(Hdpdc)2(tpy)23 were obtained via hydrothermal reactions and determined by X-ray diffraction analysis.The crystal structure data of 1 and 2 revealed that two coordination polymers were isostructural and possessed a 1D chain framework consisting of eight-coordinated Ln(III)centers.In the asymmetric unit,the two Er(III)ions in 3 were both nine-coordinated and had similar coordination environments.The Er(III)ions were bridged by dpdc2-ligands into dinuclear structures.The complexes were also characterized by IR spectra and thermogravimetric analysis.The solid fluorescence of 1 and 3 was also investigated at room temperature.展开更多
As a matter of fact,most natural structures are complex topology structures with intricate holes or irregular surface morphology.These structures can be used as lightweight infill,porous scaffold,energy absorber or mi...As a matter of fact,most natural structures are complex topology structures with intricate holes or irregular surface morphology.These structures can be used as lightweight infill,porous scaffold,energy absorber or micro-reactor.With the rapid advancement of 3D printing,the complex topology structures can now be efficiently and accurately fabricated by stacking layered materials.The novel manufacturing technology and application background put forward new demands and challenges to the current design methodologies of complex topology structures.In this paper,a brief review on the development of recent complex topology structure design methods was provided;meanwhile,the limitations of existing methods and future work are also discussed in the end.展开更多
文摘Aim To present a quantitative method for structural complexity analysis and evaluation of information systems. Methods Based on Petri net modeling and analysis techniques and with the aid of mathematical tools in general net theory(GNT), a quantitative method for structure description and analysis of information systems was introduced. Results The structural complexity index and two related factors, i.e. element complexity factor and connection complexity factor were defined, and the relations between them and the parameters of the Petri net based model of the system were derived. Application example was presented. Conclusion The proposed method provides a theoretical basis for quantitative analysis and evaluation of the structural complexity and can be applied in the general planning and design processes of the information systems.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12275179,11875042,and 12150410309)the Natural Science Foundation of Shanghai(Grant No.21ZR1443900).
文摘The suprachiasmatic nucleus in the hypothalamus is the master circadian clock in mammals,coordinating physiological processes with the 24-hour day–night cycle.Comprising various cell types,the suprachiasmatic nucleus(SCN)integrates environmental signals to maintain complex and robust circadian rhythms.Understanding the complexity and synchrony within SCN neurons is essential for effective circadian clock function.Synchrony involves coordinated neuronal firing for robust rhythms,while complexity reflects diverse activity patterns and interactions,indicating adaptability.Interestingly,the SCN retains circadian rhythms in vitro,demonstrating intrinsic rhythmicity.This study introduces the multiscale structural complexity method to analyze changes in SCN neuronal activity and complexity at macro and micro levels,based on Bagrov et al.’s approach.By examining structural complexity and local complexities across scales,we aim to understand how tetrodotoxin,a neurotoxin that inhibits action potentials,affects SCN neurons.Our method captures critical scales in neuronal interactions that traditional methods may overlook.Validation with the Goodwin model confirms the reliability of our observations.By integrating experimental data with theoretical models,this study provides new insights into the effects of tetrodotoxin(TTX)on neuronal complexities,contributing to the understanding of circadian rhythms.
文摘The inclusion complex of β-cyclodextrin with m-nitrophenoxyacetic acid was studied by single crystal X-ray diffraction,2D NMR spectroscopy and semi-empirical methods AMI.The crystallographic study shows that two β-cyclodextrins are held together by hydrogen bonds to form head-to-head dimers.The disordered vip molecule adjusts itself to attain the most stable accommodation into the cavity in which the nitro group is located at the dimer interface while the carboxyl group is buried in the primary hydroxyl groups of β-cyclodextrin.The vip inside the cavity is disordered over two sites and exhibits mobility.Moreover,2D NMR spectroscopy and theoretical study show the same inclusion behavior.In comparison to the inclusion complex of β-cyclodextrin with p-nitrophenoxyacetic acid,the host-vip stoichiometries are different,i.e.,2：1 for m-nitrophenoxyacetic acid and 1：1 for p-nitrophenoxyacetic acid,while the inclusion orientation and the packing pattern of the host are similar in both complexes.
基金supported by the National Major Science and Technology Project“Test and application of reconnaissance and evaluation technologies for shale gas”(No.:2016ZX05034004)the Project of China Geological Survey“Basic geologic survey of Lower Paleozoic marine shale gas in Sichuan Basin”(No.:DD20160176)+1 种基金“Survey on strategic zone of shale gas in Longmaxi Formation,Sichuan Basin”(No.:DD20160193)“Survey on shale gas enrichment conditions in Sichuan Basin”(No.:12120114071401).
文摘Marine shale gas in the southern Sichuan Basin is the most successful area of shale gas exploration and development in China.In order to open up new shale gas fields and search for new shale gas reserves and production replacement blocks,it is necessary to continuously establish and complete the standards on shale gas reservoir evaluation and area selection under different structural settings.The early exploration practice shows that shale in the mountainous complex structural area along the southwestern margin of the Sichuan Basin varies greatly in the gas bearing property,so systematical analysis and study on the shale gas enrichment mechanisms in this area is of great significance to searching for new shale gas exploration areas.Based on drilling data of 5 wells in the mountainous complex structural area along the southwestern margin of the Sichuan Basin,the main factors controlling the shale gas bearing property and the shale gas enrichment model were discussed based on the systematical experiments and analysis of the outcrops,cores and cuttings of Longmaxi Formation shale from the aspects of organic geochemistry,physical property,gas content,hydrocarbon generation history and pore evolution history,so as to lay a solid geological basis for the birth of a new shale gas area.And the following research results were obtained.First,the shale of the first submember of first Member of Longmaxi Formation(S1l11)in the mountainous complex structural area along the southwestern margin of the Sichuan Basin has an average TOC of 3.02%–4.97%and Ro of 2.38%–3.37%,and the average total gas content in local enrichment zones is up to 4.62 m^(3)/t,so it is classified as quality shale.Second,the detailed studies on hydrocarbon generation history indicate that the shale has the characteristics of“low thermal evolution rate and low maturity”.It is characterized by late hydrocarbon generation,low thermal evolution rate,low current maturity and short late diffusion time,which are favorable for shale gas enrichment.Third,the pore evolution history reveals that shale pore evolution can be divided into six stages,i.e.,sharp pore reduction,pore reduction,organic pore formation,pore preservation,organic pore dissipation and karstification,and organic pore and TOC are the most direct control factors of shale gas content.Fourth,favorable shelf facies belt is conducive to the formation of large-scale reservoir space and effective pores,and diversities of preservation conditions under different structural styles and at different structural positions control different pore evolution stages.The shale gas in the mountainous complex structural area is characterized by horizontal zoning and differential enrichment.“Low thermal evolution rate and low maturity”and“slow structural uplifting”are beneficial to the long-term enrichment and preservation of shale gas.In conclusion,the mountainous complex structural area along the southwestern margin of the Sichuan Basin has a shale gas enrichment model of“sedimentation controlling source rocks,diagenesis controlling reservoirs and structure controlling preservation”.This research result provides idea and reference for searching for new shale gas areas and fields.
基金the Advisory Group on Inter-national Agricultural Research(BEAF)at the German Agency for International Cooperation(GIZ)within the German Ministry for Economic Cooperation(BMZ)for funding this research(project number 08.7860.3-001.00“Making the Mekong Con-nected”-MMC).
文摘The horizontal distribution of stems, stand density and the differentiation of tree dimensions are among the most important aspects of stand structure. An increasing complexity of stand structure is often linked to a higher number of species and to greater ecological stability. For quantification, the Structural Complexity Index (SCI) describes structural complexity by means of an area ratio of the surface that is generated by connecting the tree tops of neighbouring trees to form triangles to the surface that is covered by all triangles if projected on a flat plane. Here, we propose two ecologically relevant modifications of the SCI: The degree of mingling of tree attributes, quantified by a vector ruggedness measure, and a stem density term. We investigate how these two modifications influence index values. Data come from forest inventory field plots sampled along a disturbance gradient from heavily disturbed shrub land, through secondary regrowth to mature montane rainforest stands in Mengsong, Xishuangbanna,Yunnan,China. An application is described linking structural complexity, as described by the SCI and its modified versions, to changes in species composition of insect communities. The results of this study show that the Enhanced Structural Complexity Index (ESCI) can serve as a valuable tool for forest managers and ecologists for describing the structural complexity of forest stands and is particularly valuable for natural forests with a high degree of structural complexity.
文摘Beethoven is a famous German pianist, composer, and conductor, and he set the culmination of Western classical, created a romantic music camp precedent. The size of his music in general is very ambitious, mostly concertos, symphonies, operas and other large works, technical approach and structure used is quite complex, people are left with a deep impression. But it works, while small piano pieces, also has music research value, ＂dedicated to Alice＂ is one of the few Beethoven piano pieces. This paper focuses on creative background ＂dedicated to Alice,＂ this elaborate piano works by the complexity of the analysis of the structure of this work is that it reflects the author＇ s ideological soul to explore their musical value.
基金supported by the National Key R&D Program of China(No.2021YFB1715000)the National Natural Science Foundation of China(No.52375073)。
文摘The Reliability-Based Design Optimization(RBDO)of complex engineering structures considering uncertainties has problems of being high-dimensional,highly nonlinear,and timeconsuming,which requires a significant amount of sampling simulation computation.In this paper,a basis-adaptive Polynomial Chaos(PC)-Kriging surrogate model is proposed,in order to relieve the computational burden and enhance the predictive accuracy of a metamodel.The active learning basis-adaptive PC-Kriging model is combined with a quantile-based RBDO framework.Finally,five engineering cases have been implemented,including a benchmark RBDO problem,three high-dimensional explicit problems,and a high-dimensional implicit problem.Compared with Support Vector Regression(SVR),Kriging,and polynomial chaos expansion models,results show that the proposed basis-adaptive PC-Kriging model is more accurate and efficient for RBDO problems of complex engineering structures.
基金supported by the UGent GOA project“Forest biodiversity and multifunctionality drive chronic stress-mediated dynamics in pathogen reservoirs(FORESTER)”(No.BOF20/GOA/009).
文摘Forest structural complexity influences arthropod communities by shaping habitat availability,microclimatic conditions,and resource distribution.However,the extent to which structural complexity and specific structural components drive arthropod abundance and biomass remains poorly understood in temperate forests.This study examined how local and landscape-scale forest characteristics influence arthropod communities across vertical strata(forest floor(FF),herb layer(HL),and shrub layer(SL))in 19 temperate deciduous forests in Belgium,dominated by pedunculate oak,European beech,or Canadian poplar.At the local scale,we assessed dominant tree species identity,overall forest structural complexity,and its components(vertical and horizontal structure,woody layer,herbal layer,and deadwood).At the landscape scale,we evaluated forest area,edge length,forest cover,and vegetation greenness(normalized difference vegetation index(NDVI)).Contrary to expectation,arthropod biomass and abundance did not consistently increase with higher structural complexity.Instead,woody layer complexity,dominant tree species,and NDVI emerged as key drivers,with effects varying by context and stratum.Arthropod abundance and biomass were the highest in oak-and poplar-dominated forests and the lowest in beech forests,likely due to differences in litter quality,microhabitat availability,and understory development.Woody layer complexity positively influenced forest floor arthropods in poplar forests but had a negative effect in oak forests.At the landscape scale,NDVI unexpectedly showed negative relationships with arthropod abundance across strata and with arthropod biomass in the herb layer,likely reflecting dense canopy suppression of understory productivity.Arthropod biomass on the forest floor increased with forest cover,while abundance in the shrub layer decreased with forest cover but increased with forest area.These findings highlight the complex interplay between forest structural attributes,dominant tree species,and landscape factors in shaping arthropod communities.By identifying the key drivers of arthropod abundance and biomass,this study contributes to a better understanding of biodiversity patterns in temperate forests and their ecological dynamics.
基金National Natural Science Foundation of China (50635040)National High-tech Research and Development Program (2009AA04Z302)Jiangsu Provincial Natural Science Foundation (BK2008043)
文摘Electrochemical micromachining （EMM） technology for fabricating micro structures is presented in this article. By applying ultra short pulses, dissolution of a workpiece can be restricted to the region very close to the electrode. First, an EMM system for meeting the requirements of the EMM process is established. Second, sets of experiments is carried out to investigate the influence of some of the predominant electrochemical process parameters such as electrical parameters, feed rate, electrode geometry features and electrolyte composition on machining quality, especially the influences of pulse on time on shape precision and working end shape of electrode on machined surface quality. Finally, after the preliminary experiments, a complex microstructure with good shape precision and surface quality is successfully obtained.
基金sponsored by National Science and Technology Major Project(2011ZX05046-001)
文摘Large-scale 3D physical models of complex structures can be used to simulate hydrocarbon exploration areas. The high-fidelity simulation of actual structures poses challenges to model building and quality control. Such models can be used to collect wideazimuth, multi-azimuth, and full-azimuth seismic data that can be used to verify various 3D processing and interpretation methods. Faced with nonideal imaging problems owing to the extensive complex surface conditions and subsurface structures in the oil-rich foreland basins of western China, we designed and built the KS physical model based on the complex subsurface structure. This is the largest and most complex 3D physical model built to date. The physical modeling technology advancements mainly involve 1） the model design method, 2） the model casting flow, and 3） data acquisition. A 3D velocity model of the physical model was obtained for the first time, and the model building precision was quantitatively analyzed. The absolute error was less than 3 mm, which satisfies the experimental requirements. The 3D velocity model obtained from 3D measurements of the model layers is the basis for testing various imaging methods. Furthermore, the model is considered a standard in seismic physical modeling technology.
基金the National Natural Science Foundation of China (41674131,41574118,41974146,41904109)the Fundamental Research Funds for the Central Universities (17CX06041,17CX06044)the China National Science and Technology Major Project (2016ZX05007-004,2017ZX05072-002)
文摘Electromagnetic logging while drilling(LWD)is one of the key technologies of the geosteering and formation evaluation for high-angle and horizontal wells.In this paper,we solve the dipole source-generated magnetic/electric fields in 2D formations efficiently by the 2.5D finite diff erence method.Particularly,by leveraging the field’s rapid attenuation in spectral domain,we propose truncated Gauss–Hermite quadrature,which is several tens of times faster than traditional inverse fast Fourier transform.By applying the algorithm to the LWD modeling under complex formations,e.g.,folds,fault and sandstone pinch-outs,we analyze the feasibility of the dimension reduction from 2D to 1D.For the formations with smooth lateral changes,like folds,the simplified 1D model’s results agree well with the true responses,which indicate that the 1D simplification with sliding window is feasible.However,for the formation structures with drastic rock properties changes and sharp boundaries,for instance,faults and sandstone pinch-outs,the simplified 1D model will lead to large errors and,therefore,2.5D algorithms should be applied to ensure the accuracy.
基金Project supported by the National Natural Science Foundation of China (No.90915004)the Six Talents Peak in Jiangsu Province(No.2008178)the 333 High-Level Talent Training Project of Jiangsu Province,China
文摘Simulation for stochastic wind field is very important in analyzing dynamic responses of large complex structures due to strong wind.The typical simulation method is the spectrum representation method (SRM),but the SRM has drawbacks of inferior precision in lower frequency and slow calculating speed.In view of this,the modified Fourier spectrum method (MFSM) is introduced into the simulation of stochastic wind field in this paper.In this method,phase information of wind velocity time history is determined by cross power spectral density (CPSD) between adjacent points,and the wind velocity time history with time and space correlation is generated by iterative modification for CPSD considering auto power spectral density (APSD).Simulation of the wind field for a long-span bridge is undertaken to verify the effectiveness of the MFSM.Simulation results of the SRM and the MFSM are compared.It can be concluded that the MFSM is more accurate and has higher calculation speed than the SRM.
基金Supported in part by the National Natural Science Foundation of China(60073012),National Grand Fundamental Research 973 Program of China(G1999032701),Natural Research Foundation for the Doctoral Program of Higher Education of China,Natural Science Founda
文摘To provide system designer a valid measure to evaluate the structure complexityof class diagrams objectively, this letter first proposes a method to transform a class diagramsinto a weighted class dependence graph, then presents a structure complexity measure for classdiagrams based on entropy distance.
文摘In this paper, the X-ray nondestructive test method of small defects in precision weldments with complex structure was presented. To resolve the difficulty of defect segmentation in variable grey image, the image processing based on Visual Basic programming method was adopted. The methods of automatic contrast and partial grey stretch were used to enhance the X-ray detection image which has relatively low contrast, then automatic threshold method was carried out to segment the two high intensity zones, and weld zones which contain the small defects was extracted. Smoothing and sharpen processing were proceeded on the extracted weld zones, and small defects in X-ray detection image of weldments with complex structure were segmented by using the method of background subtraction in the end. The effects of raster were eliminated, and because of that the image processing was only proceeded on the extracted weld zones, the calculated speed using the above provided algorithm was improved.
基金The project is partially supported by the NSFC(11871282,11931007)BNSF(Z190003)Nankai Zhide Foundation.
文摘The main purpose of this note is to construct almost complex or complex structures on certain isoparametric hypersurfaces in unit spheres.As a consequence,complex structures on S^(1)×S^(7)×S^(6),and on S^(10)×S^(3)×S(2)with vanishing first Chern class,are built.
文摘Inclusion compound of retinoic acid with (-cyclodextrin was prepared by coprecipitating method, the structure of resulting product was studied by elemental analysis, differential scanning caloriemetry(DSC) analysis, FT-IR spectroscopy and X-ray diffractometry, and the formed supramolecule self-assembles in aqueous solution according to molar ratio 2:1 of host-vip.
基金Supported by the NNSFC(21301087)Programs of Higher-level talents of Inner Mongolia University(SPH-IMU-30105-125135)Inner Mongolia autonomous region natural science fund project(2013MS0206)
文摘One complex with a zwitterionic dicarboxylate ligand, [Mn（L）（N3）]n 1 （L = 1-car- boxymethylpyridinium-3-carboxylate）, was synthesized and structurally characterized. Complex 1 crystallizes in triclinic, space group P1 with a = 7.570（2）, b = 7.808（2）, c = 9.232（3） A, β= 94.450（19）°, V= 489.0（3） A3, Z = 2, Mr = 277.11, Dc = 1.882 g/cm3, F（000） = 278,μ = 1.359 mm-1, S = 1.021, the final R = 0.0509 and wR = 0.1149 for 2236 observed reflections with 1 〉 2σ（I）. Complex 1 consists of two-dimensional coordination layers in which the anionic uniform chains with mixed triple bridges （one end-on （EO） azide and two syn-syn carboxylates） are cross-linked by the flexible cationic N-methylpyridinium spacers. Magnetic studies demonstrated that the triple bridge in 1 transmits antiferromagnetic coupling between the Mn（Ⅱ） ions.
基金supported by the National Natural Science Foundation of China(Nos.12172078,51576026)Fundamental Research Funds for the Central Universities in China(No.DUT21LK04)。
文摘Accurately solving transient nonlinear inverse heat conduction problems in complex structures is of great importance to provide key parameters for modeling coupled heat transfer process and the structure’s optimization design.The finite element method in ABAQUS is employed to solve the direct transient nonlinear heat conduction problem.Improved particle swarm optimization(PSO)method is developed and used to solve the transient nonlinear inverse problem.To investigate the inverse performances,some numerical tests are provided.Boundary conditions at inaccessible surfaces of a scramjet combustor with the regenerative cooling system are inversely identified.The results show that the new methodology can accurately and efficiently determine the boundary conditions in the scramjet combustor with the regenerative cooling system.By solving the transient nonlinear inverse problem,the improved particle swarm optimization for solving the transient nonlinear inverse heat conduction problem in a complex structure is verified.
基金Project supported by the Nonprofit Technology&Research in Zhejiang(2011C37010)sponsored by the K.C.Wong Magna Fund in Ningbo University,the Ningbo Municipal Natural Science Foundation(2010A610160)the Subject Object(xk1070)and Foundation(20111045)of Ningbo University
文摘Two 1D coordination polymers[Ln2(dpdc)3(tpy)2·H2O]n[Ln=Nd 1,Yb 2,H2dpdc=2,2'-biphenyldicarboxylic acid and tpy=2,2':6',2''-terpyridine]and one dinuclear complex Er2(dpdc)2(Hdpdc)2(tpy)23 were obtained via hydrothermal reactions and determined by X-ray diffraction analysis.The crystal structure data of 1 and 2 revealed that two coordination polymers were isostructural and possessed a 1D chain framework consisting of eight-coordinated Ln(III)centers.In the asymmetric unit,the two Er(III)ions in 3 were both nine-coordinated and had similar coordination environments.The Er(III)ions were bridged by dpdc2-ligands into dinuclear structures.The complexes were also characterized by IR spectra and thermogravimetric analysis.The solid fluorescence of 1 and 3 was also investigated at room temperature.
基金supported by Science Fund for Creative Research Groups of National Natural Science Foundation of China(No.51521064)the National Nature Science Foundation of China(No.51575483).
文摘As a matter of fact,most natural structures are complex topology structures with intricate holes or irregular surface morphology.These structures can be used as lightweight infill,porous scaffold,energy absorber or micro-reactor.With the rapid advancement of 3D printing,the complex topology structures can now be efficiently and accurately fabricated by stacking layered materials.The novel manufacturing technology and application background put forward new demands and challenges to the current design methodologies of complex topology structures.In this paper,a brief review on the development of recent complex topology structure design methods was provided;meanwhile,the limitations of existing methods and future work are also discussed in the end.
