In this paper, we make a comparative analysis and correlation test for the seismic activities in the South Japan and the Ludong-Huanghai block （a secondary tectonic unit in the North China） and approach the relation...In this paper, we make a comparative analysis and correlation test for the seismic activities in the South Japan and the Ludong-Huanghai block （a secondary tectonic unit in the North China） and approach the relationship between the energy release processes of these two areas by using co-integration analysis and Granger causality test for the time series of random variables. The results show that the seismic activities in these two areas are correlative and synchronous to a certain extent, and their release series of cumulative strain energy are contemporaneously correlative. Both energy series are first-order difference stationary processes and there is secular and steady co-integration between them. We make a positive analysis on the first-order difference energy series through Granger causality test based on vector error correction （VEC） model and find there is unilateral Granger causality and prominent co-integration between the two energy release processes.展开更多
A correlation tracking algorithm based on template partition motion estimation proposed for improving real time performance of the conventional correlation matching algorithms. The target trajectory fitted using the l...A correlation tracking algorithm based on template partition motion estimation proposed for improving real time performance of the conventional correlation matching algorithms. The target trajectory fitted using the least square with equal space in whole interval and the target prediction point is found out. According to the requirements of block motion estimation(BME) algorithm,the template divided into some macro blocks. The searching process is conducted by using diamond search algorithm around the prediction point and the optimal motion vector of each block is calculated. A point corresponding to the motion vector with the best matching is taken as a rough matching point of the template. The relation of relative position between the block with matching point and the searching area determined to decide whether to conduct precise matching search or to construct a new search area in the gradient direction. The target tracking experiment results show that over 70% time cost can be reduced caompared with the conventional correlation matching algorithm based on full search method.展开更多
The paper describes a method for monitoring CO2 leakage in geological carbon dioxide sequestration. A real time monitoring parameter, apparent leakage flux(ALF), is presented to monitor abnormal CO2 leakage, which can...The paper describes a method for monitoring CO2 leakage in geological carbon dioxide sequestration. A real time monitoring parameter, apparent leakage flux(ALF), is presented to monitor abnormal CO2 leakage, which can be calculated by atmospheric CO2 and O2 data. The computation shows that all ALF values are close to zero-line without the leakage. With a step change or linear perturbation of concentration to the initial CO2 concentration data with no leakage, ALF will deviate from background line. Perturbation tests prove that ALF method is sensitive to linear perturbation but insensitive to step change of concentration. An improved method is proposed based on real time analysis of surplus CO2 concentration in least square regression process, called apparent leakage flux from surplus analysis(ALFs), which is sensitive to both step perturbation and linear perturbations of concentration. ALF is capable of detecting concentration increase when the leakage occurs while ALFs is useful in all periods of leakage. Both ALF and ALFs are potential approaches to monitor CO2 leakage in geosequestration project.展开更多
As one of the lakes on the Yunnan-Guizhou plateau, Lake Chenghai, which is a typical closed lake with the precipitation accounting for one-third or more of the annual water input, has a high total salinity (almost lik...As one of the lakes on the Yunnan-Guizhou plateau, Lake Chenghai, which is a typical closed lake with the precipitation accounting for one-third or more of the annual water input, has a high total salinity (almost like a saline lake).The inorganic C,O isotopic composition of lake sediments bears much sensitive information about environmental change in the catchment, while their correlations revealed the hydrological conditions under which the lake was closed. Their compositional variations are controlled by temperature, precipitation, photosynthesis, dissolving equilibrium of the carbonate system and hydrological condition. According to our research on inorganic C, O isotopic composition of Lake Chenghai sediments, we investigated the environmental change of this catchment several decades ago. The results showed that Lake Chenghai has kept good hydrological closing conditions in the past several decades, as indicated by the good correlation of inorganic C, O isotopic composition of sediments; and that the environmental change in this catchment shows a tendency of periodical evolution on a 10\+\{-11\}-years scale, although the signal noise is relatively high at the bottom of the sediment core. And we also can extend C, O isotopes, a sensitive environmental indicator, to nearly saline lake environments with a high degree of mineralization.展开更多
The high-precision GPS data observed from the northeast margin of the Qinghai-Xizang （Tibet） block and the Sichuan-Yunnan GPS monitoring areas in 1991 （1993）, 1999 and 2001 revealed that： before the Kunlun earthq...The high-precision GPS data observed from the northeast margin of the Qinghai-Xizang （Tibet） block and the Sichuan-Yunnan GPS monitoring areas in 1991 （1993）, 1999 and 2001 revealed that： before the Kunlun earthquake with Ms =8.1 on November 14, 2001, the dynamic variation features of horizontal movement-deformation field in the north and east marginal tectonic areas of the Qinghai-Xizang （Tibet） block had some correlated features. That is to say, under the general background of inherited movement, the movement intensifies in the two areas weakened synchronously and the state of deformation changed when the great earthquake was impending. Analysis and study in connection with geological structures showed that before the Kunlun Ms8.1 earthquake, the correlated variations of movement-deformation on the boundaries of Qinghai-Xizang （Tibet） block were related to the disturbing stress field caused by the extensive and rapid stress-strain accumulation in the late stage of large earthquake preparation. Owing to the occurrence of large earthquake inside the block, the release of large amount of strain energy, and the adjustment of tectonic stress field, in relevant structural positions （especially zones not penetrated by historical strong earthquake ruptures） in boundary zones where larger amount of strain energy was accumulated, stress-strain may be further accumulated or else released through rupture.展开更多
Development of the prefrontal cortex and its connectivity with different cortical areas has strong implications for the improvement of working memory. The aim of this research was to characterize the interhemispheric ...Development of the prefrontal cortex and its connectivity with different cortical areas has strong implications for the improvement of working memory. The aim of this research was to characterize the interhemispheric (INTER) prefrontal and hemispheric (INTRA) frontopolar-dorsolateral prefrontal and dorsolateral prefrontal-parietal correlation (r) in children, adolescents and adults during performance of a visuospatial working memory task (VSWM). INTERr and INTRAr of 36 different aged male participants (11 - 13, 18 - 20 and 26 - 30 years old) were calculated during performance of the Corsi Block-Tapping task, which assessed VSWM. On this task, children showed lower correct responses than adolescents and adults. Adults also showed lower total execution times than children and adolescents, with a more efficient performance. On the EEGs, the older groups showed both higher interfrontal correlations and left and right prefronto-parietal correlations than children. According to our results, the progressive efficiency in VSWM is related to differences in EEG patterns among children, adolescents and adults.展开更多
The stratigraphic correlation of well logs plays an essential role in characterizing subsurface reservoirs.However,it suffers from a small amount of training data and expensive computing time.In this work,we propose t...The stratigraphic correlation of well logs plays an essential role in characterizing subsurface reservoirs.However,it suffers from a small amount of training data and expensive computing time.In this work,we propose the Attention Based Dense Network(ASDNet)for the stratigraphic correlation of well logs.To implement the suggested model,we first employ the attention mechanism to the input well logs,which can effectively generate the weighted well logs to serve for further feature extraction.Subsequently,the DenseNet is utilized to achieve good feature reuse and avoid gradient vanishing.After model training,we employ the ASDNet to the testing data set and evaluate its performance based on the well log data set from Northwest China.Finally,the numerical results demonstrate that the suggested ASDNet provides higher prediction accuracy for automated stratigraphic correlation of well logs than state-of-the-art contrastive UNet and SegNet.展开更多
The sea-ice concentration in the Northern Hemisphere, 500 hPa height, sea-level pressure and 1000-500 hPa thickness of monthly mean data are examined for the period 1953-1989, with emphasis on the winter season.Relati...The sea-ice concentration in the Northern Hemisphere, 500 hPa height, sea-level pressure and 1000-500 hPa thickness of monthly mean data are examined for the period 1953-1989, with emphasis on the winter season.Relationships between large-scale patterns of atmospheric variability and sea-ice variability are investigated, making use of the correlation method. The analysis is conducted for the Atlantic sectors. In agreement with earlier studies based upon monthly mean data on sea-ice concentration, the strongest sea-ice pattern is composed of a dipole with opposing centers of action in the Davis Straits / Labrador Sea region and the Greenland and Barents Seas. Its temporal variability is strongly coupled to the atmospheric North Atlantic Oscillation (NAO). The relationship between the two patterns is strongest with the atmosphere leading the ocean. The polarity of the NAO is associated with Greenland blocking episodes, during which the influence of the atmosphere is strong enough to temporarily halt the climatological mean advance of the ice edge in some regions and substantially accelerate it in others.The relationships between the fields are indicative of local forcing of sea-ice in most regions, with wind stress and thermodynamic fluxes at the air-sea interface both contributing.展开更多
The structural organization of initially random errors evolving in abarotropic tangent linear model, with time-dependent basic states taken from analyses, is examinedfor cases of block development, maturation and deca...The structural organization of initially random errors evolving in abarotropic tangent linear model, with time-dependent basic states taken from analyses, is examinedfor cases of block development, maturation and decay in the Southern Hemisphere atmosphere duringApril, November, and December 1989. The statistics of 100 evolved errors are studied for six-dayperiods and compared with the growth and structures of fast growing normal modes and finite-timenormal modes (FTNMs). The amplification factors of most initially random errors are slightly lessthan those of the fastest growing FTNM for the same time interval. During their evolution, thestandard deviations of the error fields become concentrated in the regions of rapid dynamicaldevelopment, particularly associated with developing and decaying blocks. We have calculatedprobability distributions and the mean and standard deviations of pattern correlations between eachof the 100 evolved error fields and the five fastest growing FTNMs for the same time interval. Themean of the largest pattern correlation, taken over the five fastest growing FTNMs, increases withincreasing time interval to a value close to 0.6 or larger after six days. FTNM 1 generally, but notalways, gives the largest mean pattern correlation with error fields. Corresponding patterncorrelations with the fast growing normal modes of the instantaneous basic state flow aresignificant' but lower than with FTNMs. Mean pattern correlations with fast growing FTNMs increasefurther when the time interval is increased beyond six days.展开更多
Block-in-matrix-soils(bimsoils)are geological mixtures that have distinct structures consisting of relatively strong rock blocks and weak matrix soils.It is still a challenge to evaluate the mechanical behaviors of bi...Block-in-matrix-soils(bimsoils)are geological mixtures that have distinct structures consisting of relatively strong rock blocks and weak matrix soils.It is still a challenge to evaluate the mechanical behaviors of bimsoils because of the heterogeneity,chaotic structure,and lithological variability.As a result,only very limited laboratory studies have been reported on the evolution of their internal deformation.In this study,the deformation evolution of bimsoils under uniaxial loading is investigated using real-time X-ray computed tomography(CT)and image correlation algorithm(with a rock block percentage(RBP)of 40%).Three parameters,i.e.heterogeneity coefficient(K),correlation coefficient(CC),and standard deviation(STD)of displacement fields,are proposed to quantify the heterogeneity of the motion of the rock blocks and the progressive deformation of the bimsoils.Experimental results show that the rock blocks in bimsoils are prone to forming clusters with increasing loading,and the sliding surface goes around only one side of a cluster.Based on the movement of the rock blocks recorded by STD and CC,the progressive deformation of the bimsoils is quantitatively divided into three stages:initialization of the rotation of rock blocks,formation of rock block clusters,and formation of a shear band by rock blocks with significant rotation.Moreover,the experimental results demonstrate that the meso-motion of rock blocks controls the macroscopic mechanical properties of the samples.展开更多
In the middle and second half of oilfield development,further exploration and development of petroleum reservoirs in complex fault blocks are major tasks.Based on the characteristics of fully developed farewell faults...In the middle and second half of oilfield development,further exploration and development of petroleum reservoirs in complex fault blocks are major tasks.Based on the characteristics of fully developed farewell faults in the Wenweigu oil field and the data from 3D earthquakes,RFT,HDT and other techniques,farewell faults and their distribution were identified.Conformation of the fault blocks has been provided and the precision of describing the farewell faults improved.Research technology of farewell faults has applied these methods in this region.展开更多
基金Continuous Subject of Key Project of State Science and Technology in the Tenth Five-year Plan (2004BA601B01- 04-02)Project of Science and Technology in the Tenth Five-year Plan of Shandong Province (SD10503)
文摘In this paper, we make a comparative analysis and correlation test for the seismic activities in the South Japan and the Ludong-Huanghai block （a secondary tectonic unit in the North China） and approach the relationship between the energy release processes of these two areas by using co-integration analysis and Granger causality test for the time series of random variables. The results show that the seismic activities in these two areas are correlative and synchronous to a certain extent, and their release series of cumulative strain energy are contemporaneously correlative. Both energy series are first-order difference stationary processes and there is secular and steady co-integration between them. We make a positive analysis on the first-order difference energy series through Granger causality test based on vector error correction （VEC） model and find there is unilateral Granger causality and prominent co-integration between the two energy release processes.
基金Sponsored by the National Defense Pre-Research Foundation of China
文摘A correlation tracking algorithm based on template partition motion estimation proposed for improving real time performance of the conventional correlation matching algorithms. The target trajectory fitted using the least square with equal space in whole interval and the target prediction point is found out. According to the requirements of block motion estimation(BME) algorithm,the template divided into some macro blocks. The searching process is conducted by using diamond search algorithm around the prediction point and the optimal motion vector of each block is calculated. A point corresponding to the motion vector with the best matching is taken as a rough matching point of the template. The relation of relative position between the block with matching point and the searching area determined to decide whether to conduct precise matching search or to construct a new search area in the gradient direction. The target tracking experiment results show that over 70% time cost can be reduced caompared with the conventional correlation matching algorithm based on full search method.
基金Supported by the National Natural Science Foundation of China(51276141,20936004)
文摘The paper describes a method for monitoring CO2 leakage in geological carbon dioxide sequestration. A real time monitoring parameter, apparent leakage flux(ALF), is presented to monitor abnormal CO2 leakage, which can be calculated by atmospheric CO2 and O2 data. The computation shows that all ALF values are close to zero-line without the leakage. With a step change or linear perturbation of concentration to the initial CO2 concentration data with no leakage, ALF will deviate from background line. Perturbation tests prove that ALF method is sensitive to linear perturbation but insensitive to step change of concentration. An improved method is proposed based on real time analysis of surplus CO2 concentration in least square regression process, called apparent leakage flux from surplus analysis(ALFs), which is sensitive to both step perturbation and linear perturbations of concentration. ALF is capable of detecting concentration increase when the leakage occurs while ALFs is useful in all periods of leakage. Both ALF and ALFs are potential approaches to monitor CO2 leakage in geosequestration project.
文摘As one of the lakes on the Yunnan-Guizhou plateau, Lake Chenghai, which is a typical closed lake with the precipitation accounting for one-third or more of the annual water input, has a high total salinity (almost like a saline lake).The inorganic C,O isotopic composition of lake sediments bears much sensitive information about environmental change in the catchment, while their correlations revealed the hydrological conditions under which the lake was closed. Their compositional variations are controlled by temperature, precipitation, photosynthesis, dissolving equilibrium of the carbonate system and hydrological condition. According to our research on inorganic C, O isotopic composition of Lake Chenghai sediments, we investigated the environmental change of this catchment several decades ago. The results showed that Lake Chenghai has kept good hydrological closing conditions in the past several decades, as indicated by the good correlation of inorganic C, O isotopic composition of sediments; and that the environmental change in this catchment shows a tendency of periodical evolution on a 10\+\{-11\}-years scale, although the signal noise is relatively high at the bottom of the sediment core. And we also can extend C, O isotopes, a sensitive environmental indicator, to nearly saline lake environments with a high degree of mineralization.
文摘The high-precision GPS data observed from the northeast margin of the Qinghai-Xizang （Tibet） block and the Sichuan-Yunnan GPS monitoring areas in 1991 （1993）, 1999 and 2001 revealed that： before the Kunlun earthquake with Ms =8.1 on November 14, 2001, the dynamic variation features of horizontal movement-deformation field in the north and east marginal tectonic areas of the Qinghai-Xizang （Tibet） block had some correlated features. That is to say, under the general background of inherited movement, the movement intensifies in the two areas weakened synchronously and the state of deformation changed when the great earthquake was impending. Analysis and study in connection with geological structures showed that before the Kunlun Ms8.1 earthquake, the correlated variations of movement-deformation on the boundaries of Qinghai-Xizang （Tibet） block were related to the disturbing stress field caused by the extensive and rapid stress-strain accumulation in the late stage of large earthquake preparation. Owing to the occurrence of large earthquake inside the block, the release of large amount of strain energy, and the adjustment of tectonic stress field, in relevant structural positions （especially zones not penetrated by historical strong earthquake ruptures） in boundary zones where larger amount of strain energy was accumulated, stress-strain may be further accumulated or else released through rupture.
文摘Development of the prefrontal cortex and its connectivity with different cortical areas has strong implications for the improvement of working memory. The aim of this research was to characterize the interhemispheric (INTER) prefrontal and hemispheric (INTRA) frontopolar-dorsolateral prefrontal and dorsolateral prefrontal-parietal correlation (r) in children, adolescents and adults during performance of a visuospatial working memory task (VSWM). INTERr and INTRAr of 36 different aged male participants (11 - 13, 18 - 20 and 26 - 30 years old) were calculated during performance of the Corsi Block-Tapping task, which assessed VSWM. On this task, children showed lower correct responses than adolescents and adults. Adults also showed lower total execution times than children and adolescents, with a more efficient performance. On the EEGs, the older groups showed both higher interfrontal correlations and left and right prefronto-parietal correlations than children. According to our results, the progressive efficiency in VSWM is related to differences in EEG patterns among children, adolescents and adults.
基金supported by the Key Research and Development Program of Shaanxi,China under Grant 2023-YBGY-076the Fundamental Research Funds for the Central Universities,China under Grant XZY012022086the China Postdoctoral Science Foundation Project under Grant 2022M712509.
文摘The stratigraphic correlation of well logs plays an essential role in characterizing subsurface reservoirs.However,it suffers from a small amount of training data and expensive computing time.In this work,we propose the Attention Based Dense Network(ASDNet)for the stratigraphic correlation of well logs.To implement the suggested model,we first employ the attention mechanism to the input well logs,which can effectively generate the weighted well logs to serve for further feature extraction.Subsequently,the DenseNet is utilized to achieve good feature reuse and avoid gradient vanishing.After model training,we employ the ASDNet to the testing data set and evaluate its performance based on the well log data set from Northwest China.Finally,the numerical results demonstrate that the suggested ASDNet provides higher prediction accuracy for automated stratigraphic correlation of well logs than state-of-the-art contrastive UNet and SegNet.
文摘The sea-ice concentration in the Northern Hemisphere, 500 hPa height, sea-level pressure and 1000-500 hPa thickness of monthly mean data are examined for the period 1953-1989, with emphasis on the winter season.Relationships between large-scale patterns of atmospheric variability and sea-ice variability are investigated, making use of the correlation method. The analysis is conducted for the Atlantic sectors. In agreement with earlier studies based upon monthly mean data on sea-ice concentration, the strongest sea-ice pattern is composed of a dipole with opposing centers of action in the Davis Straits / Labrador Sea region and the Greenland and Barents Seas. Its temporal variability is strongly coupled to the atmospheric North Atlantic Oscillation (NAO). The relationship between the two patterns is strongest with the atmosphere leading the ocean. The polarity of the NAO is associated with Greenland blocking episodes, during which the influence of the atmosphere is strong enough to temporarily halt the climatological mean advance of the ice edge in some regions and substantially accelerate it in others.The relationships between the fields are indicative of local forcing of sea-ice in most regions, with wind stress and thermodynamic fluxes at the air-sea interface both contributing.
文摘The structural organization of initially random errors evolving in abarotropic tangent linear model, with time-dependent basic states taken from analyses, is examinedfor cases of block development, maturation and decay in the Southern Hemisphere atmosphere duringApril, November, and December 1989. The statistics of 100 evolved errors are studied for six-dayperiods and compared with the growth and structures of fast growing normal modes and finite-timenormal modes (FTNMs). The amplification factors of most initially random errors are slightly lessthan those of the fastest growing FTNM for the same time interval. During their evolution, thestandard deviations of the error fields become concentrated in the regions of rapid dynamicaldevelopment, particularly associated with developing and decaying blocks. We have calculatedprobability distributions and the mean and standard deviations of pattern correlations between eachof the 100 evolved error fields and the five fastest growing FTNMs for the same time interval. Themean of the largest pattern correlation, taken over the five fastest growing FTNMs, increases withincreasing time interval to a value close to 0.6 or larger after six days. FTNM 1 generally, but notalways, gives the largest mean pattern correlation with error fields. Corresponding patterncorrelations with the fast growing normal modes of the instantaneous basic state flow aresignificant' but lower than with FTNMs. Mean pattern correlations with fast growing FTNMs increasefurther when the time interval is increased beyond six days.
基金This work was supported by the National Natural Science Foundation of China(Grants Nos.41972287 and 42090023)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0904).
文摘Block-in-matrix-soils(bimsoils)are geological mixtures that have distinct structures consisting of relatively strong rock blocks and weak matrix soils.It is still a challenge to evaluate the mechanical behaviors of bimsoils because of the heterogeneity,chaotic structure,and lithological variability.As a result,only very limited laboratory studies have been reported on the evolution of their internal deformation.In this study,the deformation evolution of bimsoils under uniaxial loading is investigated using real-time X-ray computed tomography(CT)and image correlation algorithm(with a rock block percentage(RBP)of 40%).Three parameters,i.e.heterogeneity coefficient(K),correlation coefficient(CC),and standard deviation(STD)of displacement fields,are proposed to quantify the heterogeneity of the motion of the rock blocks and the progressive deformation of the bimsoils.Experimental results show that the rock blocks in bimsoils are prone to forming clusters with increasing loading,and the sliding surface goes around only one side of a cluster.Based on the movement of the rock blocks recorded by STD and CC,the progressive deformation of the bimsoils is quantitatively divided into three stages:initialization of the rotation of rock blocks,formation of rock block clusters,and formation of a shear band by rock blocks with significant rotation.Moreover,the experimental results demonstrate that the meso-motion of rock blocks controls the macroscopic mechanical properties of the samples.
文摘In the middle and second half of oilfield development,further exploration and development of petroleum reservoirs in complex fault blocks are major tasks.Based on the characteristics of fully developed farewell faults in the Wenweigu oil field and the data from 3D earthquakes,RFT,HDT and other techniques,farewell faults and their distribution were identified.Conformation of the fault blocks has been provided and the precision of describing the farewell faults improved.Research technology of farewell faults has applied these methods in this region.
