[Objective] This study was to explore the difference of kriging interpolation and sequential Gaussian simulation on analyzing soil heavy metal pollution with a view to provide references for analyzing the heavy metal ...[Objective] This study was to explore the difference of kriging interpolation and sequential Gaussian simulation on analyzing soil heavy metal pollution with a view to provide references for analyzing the heavy metal pollution of soil. [Method] The sampling data of soil copper from a county of Liaocheng, Shandong Province was set as the study objective. Kriging interpolation and sequential Gaussian simu- lation were used to simulate the spatial distribution of soil copper. And 30 sampling points were selected as the cross-validation data set to compare the two interpola- tion methods. [Result] Kriging method and Gaussian sequential simulation have their own advantages on simulating mean segment and extreme segment, therefore, re- searchers should choose the proper method based on the characteristics of test data and application purposes. [Conclusion] Analysis of soil heavy metal pollution is the prerequisite for soil management and ecological restoration. The result of this study is of important significance for choosing different interpolating and simulating methods to analyze soil heavy metal pollution based on different purposes.展开更多
It is difficult to temporally and spatially track and characterize the slurry viscosity in flowing water during grouting simulation.In this study,a sequential flow and solidification(SFS)method considering the spatial...It is difficult to temporally and spatially track and characterize the slurry viscosity in flowing water during grouting simulation.In this study,a sequential flow and solidification(SFS)method considering the spatial-temporal evolution of slurry viscosity in flowing water in karst conduit is proposed.First,a time-dependent model for the threshold function of slurry viscosity is established.During the grouting process,the spatial-temporal evolution of slurry viscosity is revealed by tracking the diffusion behavior of the slurry injected at different times.This method is capable of describing the gradual solidification process of the slurry during grouting.Furthermore,a physical model of grouting in a karst conduit is developed.Second,the effectiveness of the SFS method in grouting simulation is verified by the experiment of grouting conduit in flowing water.The SFS method enables real-time monitoring of fluid velocity and pressure during grouting in flowing water and provides a feasible calculation method for revealing the grouting plugging mechanism in complex karst conduits at different engineering scales.In addition,it can be used to guide the design of grouting tests in flowing water,improve cost efficiency,and provide theoretical basis for optimizing grouting design and slurry selection.展开更多
Risk quantification in grade is critical for mine design and planning.Grade uncertainty is assessed using multiple grade realizations,from geostatistical conditional simulations,which are effective to evaluate local o...Risk quantification in grade is critical for mine design and planning.Grade uncertainty is assessed using multiple grade realizations,from geostatistical conditional simulations,which are effective to evaluate local or global uncertainty by honouring spatial correlation structures.The sequential Gaussian conditional simulation was used to assess uncertainty of grade estimates and illustrate simulated models in Sivas gold deposit,Turkey.In situ variability and risk quantification of the gold grade were assessed by probabilistic approach based on the sequential Gaussian simulations to yield a series of conditional maps characterized by equally probable spatial distribution of the gold grade for the study area.The simulation results were validated by a number of tests such as descriptive statistics,histogram,variogram and contour map reproductions.The case study demonstrates the efficiency of the method in assessing risk associated with geological and engineering variable such as the gold grade variability and distribution.The simulated models can be incorporated into exploration,exploitation and scheduling of the gold deposit.展开更多
Sequential-modular-based process flowsheeting software remains an indispensable tool for process design,control,and optimization.Yet,as the process industry advances in intelligent operation and maintenance,convention...Sequential-modular-based process flowsheeting software remains an indispensable tool for process design,control,and optimization.Yet,as the process industry advances in intelligent operation and maintenance,conventional sequential-modular-based process-simulation techniques present challenges regarding computationally intensive calculations and significant central processing unit(CPU)time requirements,particularly in large-scale design and optimization tasks.To address these challenges,this paper proposes a novel process-simulation parallel computing framework(PSPCF).This framework achieves layered parallelism in recycling processes at the unit operation level.Notably,PSPCF introduces a groundbreaking concept of formulating simulation problems as task graphs and utilizes Taskflow,an advanced task graph computing system,for hierarchical parallel scheduling and the execution of unit operation tasks.PSPCF also integrates an advanced work-stealing scheme to automatically balance thread resources with the demanding workload of unit operation tasks.For evaluation,both a simpler parallel column process and a more complex cracked gas separation process were simulated on a flowsheeting platform using PSPCF.The framework demonstrates significant time savings,achieving over 60%reduction in processing time for the simpler process and a 35%–40%speed-up for the more complex separation process.展开更多
The epidermal growth factor receptor（EGFR）—tyrosine kinase inhibitors（TKIs） monotherapies have limited efficacy in the treatment of EGFR mutation-negative non-small cell lung cancers（NSCLCs）. In the present stu...The epidermal growth factor receptor（EGFR）—tyrosine kinase inhibitors（TKIs） monotherapies have limited efficacy in the treatment of EGFR mutation-negative non-small cell lung cancers（NSCLCs）. In the present study, we aimed to investigate the combined effect of erlotinib（ER） and cabozantinib（CAB） on NSCLC cell lines harboring wild-type EGFR and to optimize the dosage regimens using pharmacodynamic（PD） modeling and simulation. Therefore, we examined the combined effect of ER and CAB on cell viability, cloning, apoptosis induction, migration and growth dynamics in H1299 and A549 cells. PD modeling and simulation were also performed to quantitatively describe the H1299 cells growth dynamics and to optimize the dosage regimens as well. Our results showed that CAB effectively enhanced the sensitivity of both cell lines to ER. The PD models fitted the data well, and some important parameters were obtained. The exponential（λ_0） and linear（λ_1） growth rates of H1299 cells were 0.0241 h^（–1） and 360 cells？h^（–1）, respectively. The Emax of ER and CAB was 0.0091 h^（–1） and 0.0085 h^（–1）, and the EC50 was 0.812 μM and 1.16 μM, respectively. The synergistic effect observed in the experiments was further confirmed by the estimated combination index φ（1.37）,（95% confidence interval： 1.24–1.50）, obtained from PD modeling. Furthermore, the dosage regimens were optimized using simulations. In summary, both the experimental and modeling results demonstrated the synergistic interaction between ER and CAB in NSCLCs without EGFR mutations. Sequential combinations of ER and CAB provided an option for the therapy of the NSCLCs with wild-type EGFR, which would provide some references for preclinical study and translational research as well.展开更多
On the basis of local measurements of hydraulic conductivity, geostatistical methods have been found to be useful in heterogeneity characterization of a hydraulic conductivity field on a regional scale. However, the m...On the basis of local measurements of hydraulic conductivity, geostatistical methods have been found to be useful in heterogeneity characterization of a hydraulic conductivity field on a regional scale. However, the methods are not suited to directly integrate dynamic production data, such as, hydraulic head and solute concentration, into the study of conductivity distribution. These data, which record the flow and transport processes in the medium, are closely related to the spatial distribution of hydraulic conductivity. In this study, a three-dimensional gradient-based inverse method--the sequential self-calibration （SSC） method--is developed to calibrate a hydraulic conductivity field, initially generated by a geostatistical simulation method, conditioned on tracer test results. The SSC method can honor both local hydraulic conductivity measurements and tracer test data. The mismatch between the simulated hydraulic conductivity field and the reference true one, measured by its mean square error （MSE）, is reduced through the SSC conditional study. In comparison with the unconditional results, the SSC conditional study creates the mean breakthrough curve much closer to the reference true curve, and significantly reduces the prediction uncertainty of the solute transport in the observed locations. Further, the reduction of uncertainty is spatially dependent, which indicates that good locations, geological structure, and boundary conditions will affect the efficiency of the SSC study results.展开更多
Several structural design parameters for the description of the geometric features of a hollow fan blade were determined.A structural design optimization model of a hollow fan blade which based on the strength constra...Several structural design parameters for the description of the geometric features of a hollow fan blade were determined.A structural design optimization model of a hollow fan blade which based on the strength constraint and minimum mass was established based on the finite element method through these parameters.Then,the sequential quadratic programming algorithm was employed to search the optimal solutions.Several groups of value for initial design variables were chosen,for the purpose of not only finding much more local optimal results but also analyzing which discipline that the variables according to could be benefit for the convergence and robustness.Response surface method and Monte Carlo simulations were used to analyze whether the objective function and constraint function are sensitive to the variation of variables or not.Then the robust results could be found among a group of different local optimal solutions.展开更多
Copula functions have been widely used in stochastic simulation and prediction of streamflow.However,existing models are usually limited to single two-dimensional or three-dimensional copulas with the same bivariate b...Copula functions have been widely used in stochastic simulation and prediction of streamflow.However,existing models are usually limited to single two-dimensional or three-dimensional copulas with the same bivariate block for all months.To address this limitation,this study developed a mixed D-vine copula-based conditional quantile model that can capture temporal correlations.This model can generate streamflow by selecting different historical streamflow variables as the conditions for different months and by exploiting the conditional quantile functions of streamflows in different months with mixed D-vine copulas.The up-to-down sequential method,which couples the maximum weight approach with the Akaike information criteria and the maximum likelihood approach,was used to determine the structures of multivariate Dvine copulas.The developed model was used in a case study to synthesize the monthly streamflow at the Tangnaihai hydrological station,the inflow control station of the Longyangxia Reservoir in the Yellow River Basin.The results showed that the developed model outperformed the commonly used bivariate copula model in terms of the performance in simulating the seasonality and interannual variability of streamflow.This model provides useful information for water-related natural hazard risk assessment and integrated water resources management and utilization.展开更多
The ionization time in sequential double ionization with an elliptically polarized laser pulse has been examined theo- retically using a semiclassical method. The significant discrepancy between the ionization time fo...The ionization time in sequential double ionization with an elliptically polarized laser pulse has been examined theo- retically using a semiclassical method. The significant discrepancy between the ionization time for parallel and anti-parallel electron emission is predicted numerically for the first time. The impact of the carrier envelope phase offset is also studied in this work.展开更多
This paper presents a three-dimensional geological reservoir model created using stochastic simulation. The oil field presented is an East African oil field formed by a structural trap. Data analysis and transformatio...This paper presents a three-dimensional geological reservoir model created using stochastic simulation. The oil field presented is an East African oil field formed by a structural trap. Data analysis and transformations were conducted on the properties before simulation. The variogram was used to measure the spatial correlation of cell-based facies modeling, and porosity and permeability modeling. Two main lithologies were modelled using sequential indicator simulation, sand and shale. Sand had a percentage of 26.8% and shale of 73.2%. There was a clear property distribution trend of sand and shale from the southwest to the northeastern part of a reservoir. The distribution trend of the facies resembled the proposed depositional model of the reservoir. Simulations show that average porosity and permeability of the reservoir are about 20% and 1004 mD, respectively. Average water saturation was 64%. STOIIP volume of 689.42 MMbbls was calculated. The results of simulation showed that the south eastern part of the reservoir holds higher volumes of oil. In conclusion, the model gave a better geological understanding of the geology of the area and can be used for decision making about the future development of the reservoir, prediction performance and uncertainty analysis.展开更多
In order to simulate the flowing of shale gas in multi-scale media,we established a mathematical model for the unsteady seepage of multi-stage fractured horizontal wells in shale gas reservoirs in consideration of the...In order to simulate the flowing of shale gas in multi-scale media,we established a mathematical model for the unsteady seepage of multi-stage fractured horizontal wells in shale gas reservoirs in consideration of the flowing characteristics of shale gas in matrix,natural fractures and large-scale artificial fractures.Grid division in the simulation region was carried out by means of nonstructural tetrahedral grid.Then,a 3D numerical model for the seepage of shale gas was established discretely using finite volume method and solved using sequence solution method.Finally,the production performance of multi-stage fractured horizontal wells in shale gas reservoirs and the reservoir pressure distribution were simulated,and the simulation results were analyzed.And the following research results were obtained.First,the gas production rates of multi-stage fractured horizontal wells calculated by this newly established numerical simulation method are basically consistent with the calculation results by the commercial numerical simulation software Eclipse,which proves that this new model is accurate and feasible.Second,the gas production rates of horizontal wells calculated by the sequential solution method are different from those calculated by the fully implicit solution method in the early production stages,but as the calculation progresses,both of them tend to be consistent,which further verifies the accuracy of this new model.Third,desorbed gas plays a supplementary role to reservoir pressure,but its function is limited,and its effect on gas production is little.As the production goes on,the percentage of desorbed gas increases gradually.Fourth,the key to the stimulation of shale-gas horizontal wells is to determine the number of fractured sections rationally and create longer artificial fractures.In conclusion,the research results are conducive to the design of stimulated reservoir volumes(SRVs)of shale gas reservoirs and the prediction of production performance of multi-stage fractured horizontal wells.展开更多
According to a lot of practical data in Liujialiang Mine and reliability theory and result of computer simulation, operation regularity of fully mechanized sublevel caving mining production system in the condition of ...According to a lot of practical data in Liujialiang Mine and reliability theory and result of computer simulation, operation regularity of fully mechanized sublevel caving mining production system in the condition of gently inclined complicated geological structure and production shortcomings are found out and reliability of system and output of the working face are predicted finally.展开更多
In this paper, the glitching activity and process variations in the maximum power dissipation estimation of CMOS circuits are introduced. Given a circuit and the gate library, a new Genetic Algorithm (GA)-based techni...In this paper, the glitching activity and process variations in the maximum power dissipation estimation of CMOS circuits are introduced. Given a circuit and the gate library, a new Genetic Algorithm (GA)-based technique is developed to determine the maximum power dissipation from a statistical point of view. The simulation on 1SCAS-89 benchmarks shows that the ratio of the maximum power dissipation with glitching activity over the maximum power under zero-delay model ranges from 1.18 to 4.02. Compared with the traditional Monte Carlo-based technique, the new approach presented in this paper is more effective.展开更多
Along with the completion of HGP （human genome project）, huge amounts of genetic data constantly emerge. Research suggests that genes are not in independent existence and the expression of a gene will promote or inh...Along with the completion of HGP （human genome project）, huge amounts of genetic data constantly emerge. Research suggests that genes are not in independent existence and the expression of a gene will promote or inhibit the expression of another gene; if the expression of a gene makes the biochemical environment of ceils changed, the expression of a series of genes will be affected. In order to get a better understanding of the relationship between genes, all sorts of gene regulatory network models have been established by scientists. In this paper, a variety of gene regulatory networks are first introduced according to the process of this subject research, and then the most basic network （i.e. Boolean network） is emphatically analyzed, and then a new method （i.e. Boolean network based on the theory of circuit） to describe Boolean network is drawn forth. After the shortcomings of the Boolean network proposed in the past are analyzed, a simulation circuit Boolean model is established using EDA technology in order to improve the Boolean network.展开更多
The component aging has become a significant concern worldwide,and the frequent failures pose a serious threat to the reliability of modern power systems.In light of this issue,this paper presents a power system relia...The component aging has become a significant concern worldwide,and the frequent failures pose a serious threat to the reliability of modern power systems.In light of this issue,this paper presents a power system reliability evaluation method based on sequential Monte Carlo simulation(SMCS)to quantify system reliability considering multiple failure modes of components.First,a three-state component reliability model is established to explicitly describe the state transition process of the component subject to both aging failure and random failure modes.In this model,the impact of each failure mode is decoupled and characterized as the combination of two state duration variables,which are separately modeled using specific probability distributions.Subsequently,SMCS is used to integrate the three-state component reliability model for state transition sequence generation and system reliability evaluation.Therefore,various reliability metrics,including the probability of load curtailment(PLC),expected frequency of load curtailment(EFLC),and expected energy not supplied(EENS),can be estimated.To ensure the applicability of the proposed method,Hash table grouping and the maximum feasible load level judgment techniques are jointly adopted to enhance its computational performance.Case studies are conducted on different aging scenarios to illustrate and validate the effectiveness and practicality of the proposed method.展开更多
基金Supported by the Science and Technology Development Program of Shandong Province (Soft Science) (2009RKB220),China~~
文摘[Objective] This study was to explore the difference of kriging interpolation and sequential Gaussian simulation on analyzing soil heavy metal pollution with a view to provide references for analyzing the heavy metal pollution of soil. [Method] The sampling data of soil copper from a county of Liaocheng, Shandong Province was set as the study objective. Kriging interpolation and sequential Gaussian simu- lation were used to simulate the spatial distribution of soil copper. And 30 sampling points were selected as the cross-validation data set to compare the two interpola- tion methods. [Result] Kriging method and Gaussian sequential simulation have their own advantages on simulating mean segment and extreme segment, therefore, re- searchers should choose the proper method based on the characteristics of test data and application purposes. [Conclusion] Analysis of soil heavy metal pollution is the prerequisite for soil management and ecological restoration. The result of this study is of important significance for choosing different interpolating and simulating methods to analyze soil heavy metal pollution based on different purposes.
基金financial support from the National Natural Science Foundation of China(Grant Nos.52022053 and 51879153)the China National Postdoctoral Program for Innovative Talents(Grant No.BX2021172)。
文摘It is difficult to temporally and spatially track and characterize the slurry viscosity in flowing water during grouting simulation.In this study,a sequential flow and solidification(SFS)method considering the spatial-temporal evolution of slurry viscosity in flowing water in karst conduit is proposed.First,a time-dependent model for the threshold function of slurry viscosity is established.During the grouting process,the spatial-temporal evolution of slurry viscosity is revealed by tracking the diffusion behavior of the slurry injected at different times.This method is capable of describing the gradual solidification process of the slurry during grouting.Furthermore,a physical model of grouting in a karst conduit is developed.Second,the effectiveness of the SFS method in grouting simulation is verified by the experiment of grouting conduit in flowing water.The SFS method enables real-time monitoring of fluid velocity and pressure during grouting in flowing water and provides a feasible calculation method for revealing the grouting plugging mechanism in complex karst conduits at different engineering scales.In addition,it can be used to guide the design of grouting tests in flowing water,improve cost efficiency,and provide theoretical basis for optimizing grouting design and slurry selection.
文摘Risk quantification in grade is critical for mine design and planning.Grade uncertainty is assessed using multiple grade realizations,from geostatistical conditional simulations,which are effective to evaluate local or global uncertainty by honouring spatial correlation structures.The sequential Gaussian conditional simulation was used to assess uncertainty of grade estimates and illustrate simulated models in Sivas gold deposit,Turkey.In situ variability and risk quantification of the gold grade were assessed by probabilistic approach based on the sequential Gaussian simulations to yield a series of conditional maps characterized by equally probable spatial distribution of the gold grade for the study area.The simulation results were validated by a number of tests such as descriptive statistics,histogram,variogram and contour map reproductions.The case study demonstrates the efficiency of the method in assessing risk associated with geological and engineering variable such as the gold grade variability and distribution.The simulated models can be incorporated into exploration,exploitation and scheduling of the gold deposit.
基金supported by the National Key Research and Development Program of China(2022YFB3305900)the National Natural Science Foundation of China(Key Program)(62136003)+2 种基金the National Natural Science Foundation of China(62394345)the Major Science and Technology Projects of Longmen Laboratory(LMZDXM202206)the Fundamental Research Funds for the Central Universities.
文摘Sequential-modular-based process flowsheeting software remains an indispensable tool for process design,control,and optimization.Yet,as the process industry advances in intelligent operation and maintenance,conventional sequential-modular-based process-simulation techniques present challenges regarding computationally intensive calculations and significant central processing unit(CPU)time requirements,particularly in large-scale design and optimization tasks.To address these challenges,this paper proposes a novel process-simulation parallel computing framework(PSPCF).This framework achieves layered parallelism in recycling processes at the unit operation level.Notably,PSPCF introduces a groundbreaking concept of formulating simulation problems as task graphs and utilizes Taskflow,an advanced task graph computing system,for hierarchical parallel scheduling and the execution of unit operation tasks.PSPCF also integrates an advanced work-stealing scheme to automatically balance thread resources with the demanding workload of unit operation tasks.For evaluation,both a simpler parallel column process and a more complex cracked gas separation process were simulated on a flowsheeting platform using PSPCF.The framework demonstrates significant time savings,achieving over 60%reduction in processing time for the simpler process and a 35%–40%speed-up for the more complex separation process.
基金National Natural Science Foundation of China(NSFC,Grant No.81273583)
文摘The epidermal growth factor receptor（EGFR）—tyrosine kinase inhibitors（TKIs） monotherapies have limited efficacy in the treatment of EGFR mutation-negative non-small cell lung cancers（NSCLCs）. In the present study, we aimed to investigate the combined effect of erlotinib（ER） and cabozantinib（CAB） on NSCLC cell lines harboring wild-type EGFR and to optimize the dosage regimens using pharmacodynamic（PD） modeling and simulation. Therefore, we examined the combined effect of ER and CAB on cell viability, cloning, apoptosis induction, migration and growth dynamics in H1299 and A549 cells. PD modeling and simulation were also performed to quantitatively describe the H1299 cells growth dynamics and to optimize the dosage regimens as well. Our results showed that CAB effectively enhanced the sensitivity of both cell lines to ER. The PD models fitted the data well, and some important parameters were obtained. The exponential（λ_0） and linear（λ_1） growth rates of H1299 cells were 0.0241 h^（–1） and 360 cells？h^（–1）, respectively. The Emax of ER and CAB was 0.0091 h^（–1） and 0.0085 h^（–1）, and the EC50 was 0.812 μM and 1.16 μM, respectively. The synergistic effect observed in the experiments was further confirmed by the estimated combination index φ（1.37）,（95% confidence interval： 1.24–1.50）, obtained from PD modeling. Furthermore, the dosage regimens were optimized using simulations. In summary, both the experimental and modeling results demonstrated the synergistic interaction between ER and CAB in NSCLCs without EGFR mutations. Sequential combinations of ER and CAB provided an option for the therapy of the NSCLCs with wild-type EGFR, which would provide some references for preclinical study and translational research as well.
基金This study is partially supported by the Program of Outstanding Overseas Youth Chinese Scholar,the National Natural Science Foundation of China (No. 40528003)partially supported by USA National Science Foundation.
文摘On the basis of local measurements of hydraulic conductivity, geostatistical methods have been found to be useful in heterogeneity characterization of a hydraulic conductivity field on a regional scale. However, the methods are not suited to directly integrate dynamic production data, such as, hydraulic head and solute concentration, into the study of conductivity distribution. These data, which record the flow and transport processes in the medium, are closely related to the spatial distribution of hydraulic conductivity. In this study, a three-dimensional gradient-based inverse method--the sequential self-calibration （SSC） method--is developed to calibrate a hydraulic conductivity field, initially generated by a geostatistical simulation method, conditioned on tracer test results. The SSC method can honor both local hydraulic conductivity measurements and tracer test data. The mismatch between the simulated hydraulic conductivity field and the reference true one, measured by its mean square error （MSE）, is reduced through the SSC conditional study. In comparison with the unconditional results, the SSC conditional study creates the mean breakthrough curve much closer to the reference true curve, and significantly reduces the prediction uncertainty of the solute transport in the observed locations. Further, the reduction of uncertainty is spatially dependent, which indicates that good locations, geological structure, and boundary conditions will affect the efficiency of the SSC study results.
文摘Several structural design parameters for the description of the geometric features of a hollow fan blade were determined.A structural design optimization model of a hollow fan blade which based on the strength constraint and minimum mass was established based on the finite element method through these parameters.Then,the sequential quadratic programming algorithm was employed to search the optimal solutions.Several groups of value for initial design variables were chosen,for the purpose of not only finding much more local optimal results but also analyzing which discipline that the variables according to could be benefit for the convergence and robustness.Response surface method and Monte Carlo simulations were used to analyze whether the objective function and constraint function are sensitive to the variation of variables or not.Then the robust results could be found among a group of different local optimal solutions.
基金supported by the National Natural Science Foundation of China(Grant No.52109010)the Postdoctoral Science Foundation of China(Grant No.2021M701047)the China National Postdoctoral Program for Innovative Talents(Grant No.BX20200113).
文摘Copula functions have been widely used in stochastic simulation and prediction of streamflow.However,existing models are usually limited to single two-dimensional or three-dimensional copulas with the same bivariate block for all months.To address this limitation,this study developed a mixed D-vine copula-based conditional quantile model that can capture temporal correlations.This model can generate streamflow by selecting different historical streamflow variables as the conditions for different months and by exploiting the conditional quantile functions of streamflows in different months with mixed D-vine copulas.The up-to-down sequential method,which couples the maximum weight approach with the Akaike information criteria and the maximum likelihood approach,was used to determine the structures of multivariate Dvine copulas.The developed model was used in a case study to synthesize the monthly streamflow at the Tangnaihai hydrological station,the inflow control station of the Longyangxia Reservoir in the Yellow River Basin.The results showed that the developed model outperformed the commonly used bivariate copula model in terms of the performance in simulating the seasonality and interannual variability of streamflow.This model provides useful information for water-related natural hazard risk assessment and integrated water resources management and utilization.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11135002, 11075069, 91026021, 11075068, and 10975065)the Fundamental Research Funds for the Central Universities of China (Grant No. lzujbky-2010-k08)the Scholarship Award for Excellent Doctoral Student granted by Ministry of Education
文摘The ionization time in sequential double ionization with an elliptically polarized laser pulse has been examined theo- retically using a semiclassical method. The significant discrepancy between the ionization time for parallel and anti-parallel electron emission is predicted numerically for the first time. The impact of the carrier envelope phase offset is also studied in this work.
文摘This paper presents a three-dimensional geological reservoir model created using stochastic simulation. The oil field presented is an East African oil field formed by a structural trap. Data analysis and transformations were conducted on the properties before simulation. The variogram was used to measure the spatial correlation of cell-based facies modeling, and porosity and permeability modeling. Two main lithologies were modelled using sequential indicator simulation, sand and shale. Sand had a percentage of 26.8% and shale of 73.2%. There was a clear property distribution trend of sand and shale from the southwest to the northeastern part of a reservoir. The distribution trend of the facies resembled the proposed depositional model of the reservoir. Simulations show that average porosity and permeability of the reservoir are about 20% and 1004 mD, respectively. Average water saturation was 64%. STOIIP volume of 689.42 MMbbls was calculated. The results of simulation showed that the south eastern part of the reservoir holds higher volumes of oil. In conclusion, the model gave a better geological understanding of the geology of the area and can be used for decision making about the future development of the reservoir, prediction performance and uncertainty analysis.
基金supported by National Natural Science Foundation of China“Numerical simulation of fractured reservoirs based on nonstructural hexahedral grid model and parallel computation”(No.:51474179).
文摘In order to simulate the flowing of shale gas in multi-scale media,we established a mathematical model for the unsteady seepage of multi-stage fractured horizontal wells in shale gas reservoirs in consideration of the flowing characteristics of shale gas in matrix,natural fractures and large-scale artificial fractures.Grid division in the simulation region was carried out by means of nonstructural tetrahedral grid.Then,a 3D numerical model for the seepage of shale gas was established discretely using finite volume method and solved using sequence solution method.Finally,the production performance of multi-stage fractured horizontal wells in shale gas reservoirs and the reservoir pressure distribution were simulated,and the simulation results were analyzed.And the following research results were obtained.First,the gas production rates of multi-stage fractured horizontal wells calculated by this newly established numerical simulation method are basically consistent with the calculation results by the commercial numerical simulation software Eclipse,which proves that this new model is accurate and feasible.Second,the gas production rates of horizontal wells calculated by the sequential solution method are different from those calculated by the fully implicit solution method in the early production stages,but as the calculation progresses,both of them tend to be consistent,which further verifies the accuracy of this new model.Third,desorbed gas plays a supplementary role to reservoir pressure,but its function is limited,and its effect on gas production is little.As the production goes on,the percentage of desorbed gas increases gradually.Fourth,the key to the stimulation of shale-gas horizontal wells is to determine the number of fractured sections rationally and create longer artificial fractures.In conclusion,the research results are conducive to the design of stimulated reservoir volumes(SRVs)of shale gas reservoirs and the prediction of production performance of multi-stage fractured horizontal wells.
文摘According to a lot of practical data in Liujialiang Mine and reliability theory and result of computer simulation, operation regularity of fully mechanized sublevel caving mining production system in the condition of gently inclined complicated geological structure and production shortcomings are found out and reliability of system and output of the working face are predicted finally.
基金Supported by NSF of the United States under contract 5978 East Asia and Pacific Program 9602485
文摘In this paper, the glitching activity and process variations in the maximum power dissipation estimation of CMOS circuits are introduced. Given a circuit and the gate library, a new Genetic Algorithm (GA)-based technique is developed to determine the maximum power dissipation from a statistical point of view. The simulation on 1SCAS-89 benchmarks shows that the ratio of the maximum power dissipation with glitching activity over the maximum power under zero-delay model ranges from 1.18 to 4.02. Compared with the traditional Monte Carlo-based technique, the new approach presented in this paper is more effective.
文摘Along with the completion of HGP （human genome project）, huge amounts of genetic data constantly emerge. Research suggests that genes are not in independent existence and the expression of a gene will promote or inhibit the expression of another gene; if the expression of a gene makes the biochemical environment of ceils changed, the expression of a series of genes will be affected. In order to get a better understanding of the relationship between genes, all sorts of gene regulatory network models have been established by scientists. In this paper, a variety of gene regulatory networks are first introduced according to the process of this subject research, and then the most basic network （i.e. Boolean network） is emphatically analyzed, and then a new method （i.e. Boolean network based on the theory of circuit） to describe Boolean network is drawn forth. After the shortcomings of the Boolean network proposed in the past are analyzed, a simulation circuit Boolean model is established using EDA technology in order to improve the Boolean network.
基金supported by the National Natural Science Foundation of China(No.52022016)the Fundamental Research Funds for the Central Universities(No.2023CDJYXTD-004)the Graduate Research and Innovation Foundation of Chongqing(No.CYB22014)。
文摘The component aging has become a significant concern worldwide,and the frequent failures pose a serious threat to the reliability of modern power systems.In light of this issue,this paper presents a power system reliability evaluation method based on sequential Monte Carlo simulation(SMCS)to quantify system reliability considering multiple failure modes of components.First,a three-state component reliability model is established to explicitly describe the state transition process of the component subject to both aging failure and random failure modes.In this model,the impact of each failure mode is decoupled and characterized as the combination of two state duration variables,which are separately modeled using specific probability distributions.Subsequently,SMCS is used to integrate the three-state component reliability model for state transition sequence generation and system reliability evaluation.Therefore,various reliability metrics,including the probability of load curtailment(PLC),expected frequency of load curtailment(EFLC),and expected energy not supplied(EENS),can be estimated.To ensure the applicability of the proposed method,Hash table grouping and the maximum feasible load level judgment techniques are jointly adopted to enhance its computational performance.Case studies are conducted on different aging scenarios to illustrate and validate the effectiveness and practicality of the proposed method.
