The inconsistency of lithium-ion cells degrades battery performance,lifetime and even safety.The complexity of the cell reaction mechanism causes an irregular asymmetrical distribution of various cell parameters,such ...The inconsistency of lithium-ion cells degrades battery performance,lifetime and even safety.The complexity of the cell reaction mechanism causes an irregular asymmetrical distribution of various cell parameters,such as capacity and internal resistance,among others.In this study,the Newman electrochemical model was used to simulate the 1 C discharge curves of 100 LiMn2 O4 pouch cells with parameter variations typically produced in manufacturing processes,and the three-parameter Weibull probability model was used to analyze the dispersion and symmetry of the resulting discharge voltage distributions.The results showed that the dispersion of the voltage distribution was related to the rate of decrease in the discharge voltage,and the symmetry was related to the change in the rate of voltage decrease.The effect of the cells’capacity dominated the voltage distribution thermodynamically during discharge,and the phase transformation process significantly skewed the voltage distribution.The effects of the ohmic drop and polarization voltage on the voltage distribution were primarily kinetic.The presence of current returned the right-skewed voltage distribution caused by phase transformation to a more symmetrical distribution.Thus,the Weibull parameters elucidated the electrochemical behavior during the discharge process,and this method can guide the prediction and control of cell inconsistency,as well as detection and control strategies for cell management systems.展开更多
A two-compartment model of the universe is proposed to further refine Albert Einstein’s insight into curvature of space and the energy tensor. The two compartments are energy contained by a shell prism. The model all...A two-compartment model of the universe is proposed to further refine Albert Einstein’s insight into curvature of space and the energy tensor. The two compartments are energy contained by a shell prism. The model allows for a non-unification of fundamental forces with gravity resulting from the curvature of a space-time prism. Carrier forces travel within the prism and particles emerge from the prism. Giving a thickness to the manifold negates infinity and will allow solutions at both microscopic and cosmic levels. Geometry is the link between quantum mechanics and general relativity. Negative entropy, as proposed by Erwin Schrödinger, gives order to particles and the cosmic. The source of this energy is in the shell of the containment vessel. The acceleration of the expansion of the universe occurred when energy within the container transformed into mass, warping the space-time container and causing an explosion of the container. Star movement is explained by the surface tension of the prism of space-time.展开更多
The two-parameter lognormal distribution is a variant of the normal distribution and the three-parameter lognormal distribution is an extension of the two-parameter lognormal distribution by introducing a location par...The two-parameter lognormal distribution is a variant of the normal distribution and the three-parameter lognormal distribution is an extension of the two-parameter lognormal distribution by introducing a location parameter. The Q-Q plot of the three-parameter lognormal distribution is widely used. To obtain the Q-Q plot one needs to iteratively try different values of the shape parameter and subjectively judge the linearity of the Q-Q plot. In this paper,a mathematical method was proposed to determine the value of the shape parameter so as to simplify the generation of the Q-Q plot. Then a new probability plot was proposed,which was more easily obtained and provided more accurate parameter estimates than the Q-Q plot. These are illustrated by three realworld examples.展开更多
Based on the consistency-viscoplastic constitutive model,the static William-Warnke model with three-parameters is modified and a consistency-viscoplastic William-Warnke model with three-parameters is developed that co...Based on the consistency-viscoplastic constitutive model,the static William-Warnke model with three-parameters is modified and a consistency-viscoplastic William-Warnke model with three-parameters is developed that considers the effect of strain rates. Then,the tangent modulus of the consistency viscoplastic model is introduced and an implicit backward Elure iterative algorithm is developed. Comparisons between the numerical simulations and experimental data show that the consistency model properly provides the uniaxial and biaxial dynamic behaviors of concrete. To study the effect of strain rates on the dynamic response of concrete structures,the proposed model is used in the analysis of the dynamic response of a simply-supported beam and the results show that the strain rate has a significant effect on the displacement and stress magnitudes and distributions. Finally,the seismic responses of a 278 m high arch dam are obtained and compared by using the linear elastic model,as well as rate-independent and rate-dependent William-Warnke three-parameter models. The results indicate that the strain rate affects the first principal stresses,and the maximal equivalent viscoplastic strain rate of the arch dam. Numerical calculations and analyses reveal that considering the strain rate is important in the safety assessments of arch dams located in seismically active areas.展开更多
The power sector is an important factor in ensuring the development of the national economy.Scientific simulation and prediction of power consumption help achieve the balance between power generation and power consump...The power sector is an important factor in ensuring the development of the national economy.Scientific simulation and prediction of power consumption help achieve the balance between power generation and power consumption.In this paper,a Multi-strategy Hybrid Coati Optimizer(MCOA)is used to optimize the parameters of the three-parameter combinatorial optimization model TDGM(1,1,r,ξ,Csz)to realize the simulation and prediction of China's daily electricity consumption.Firstly,a novel MCOA is proposed in this paper,by making the following improvements to the Coati Optimization Algorithm(COA):(ⅰ)Introduce improved circle chaotic mapping strategy.(ⅱ)Fusing Aquila Optimizer,to enhance MCOA's exploration capabilities.(ⅲ)Adopt an adaptive optimal neighborhood jitter learning strategy.Effectively improve MCOA escape from local optimal solutions.(ⅳ)Incorporating Differential Evolution to enhance the diversity of the population.Secondly,the superiority of the MCOA algorithm is verified by comparing it with the newly proposed algorithm,the improved optimiza-tion algorithm,and the hybrid algorithm on the CEC2019 and CEC2020 test sets.Finally,in this paper,MCOA is used to optimize the parameters of TDGM(1,1,r,ξ,Csz),and this model is applied to forecast the daily electricity consumption in China and compared with the predictions of 14 models,including seven intelligent algorithm-optimized TDGM(1,1,r,ξ,Csz),and seven forecasting models.The experimental results show that the error of the proposed method is minimized,which verifies the validity of the proposed method.展开更多
Cutterhead loads are the key mechanical parameters for the strength design of the full face hard rock tunnel boring machine(TBM).Due to the brittle rock-breaking mechanism,the excavation loads acting on cutters fluctu...Cutterhead loads are the key mechanical parameters for the strength design of the full face hard rock tunnel boring machine(TBM).Due to the brittle rock-breaking mechanism,the excavation loads acting on cutters fluctuate strongly and show some randomness.The conventional method that using combinations of some special static loads to perform the strength design of TBM cutterhead may lead to strength failure during working practice.In this paper,a three-dimensional finite element model for coupled Cutterhead–Rock is developed to determine the cutterhead loads.Then the distribution characteristics and the influence factors of cutterhead loads are analyzed based on the numerical results.It is found that,as time changes,the normal and tangential forces acting on cutters and the total torque acting on the cutterhead approximately distribute log normally,while the total thrusts acting on the cutterhead approximately show a normal distribution.Furthermore,the statistical average values of cutterhead loads are proportional to the uniaxial compressive strength(UCS)of cutting rocks.The values also change with the penetration and the diameter of cutterhead following a power function.Based on these findings,we propose a three-parameter model for the mean of cutterhead loads and a method of generating the random cutter forces.Then the strength properties of a typical cutterhead are analyzed in detail using loads generated by the new method.The optimized cutterhead has been successfully applied in engineering.The method in this paper may provide a useful reference for the strength design of TBM cutterhead.展开更多
Background: The large potential of the soil organic carbon(SOC) pool to sequester CO2from the atmosphere could greatly ameliorate the effect of future climate change. However, the quantity of carbon stored in terrestr...Background: The large potential of the soil organic carbon(SOC) pool to sequester CO2from the atmosphere could greatly ameliorate the effect of future climate change. However, the quantity of carbon stored in terrestrial soils largely depends upon the magnitude of SOC mineralization. SOC mineralization constitutes an important part of the carbon cycle, and is driven by many biophysical variables, such as temperature and moisture.Methods: Soil samples of a pine forest, an oak forest, and a pine and oak mixed forest were incubated for 387 days under conditions with six temperature settings(5 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C) and three levels of soil moisture content(SMC, 30%, 60%, 90%). The instantaneous rate of mineralized SOC was periodically and automatically measured using a Li-Cor CO2analyzer. Based on the measured amount of mineralized SOC,carbon fractions were estimated separately via first-order kinetic one-and two-compartment models.Results: During the 387 day incubation experiment, accumulative mineralized carbon ranged from 22.89 mg carbon(C) ·g-1SOC at 30 °C and 30% SMC for the mixed forest to 109.20 mg C·g-1SOC at 15 °C and 90% SMC for the oak forest. Mineralized recalcitrant carbon varied from 18.48 mg C·g-1SOC at 30 °C and 30% SMC for the mixed forest to 104.98 mg C·g-1SOC at 15 °C and 90% SMC for the oak forest, and contributed at least 80% to total mineralized carbon.Conclusions: Based on the results of this experiment, the soil organic matter of the pure broadleaved forest is more vulnerable to soil microbial degradation in northern China; most of the amount of the mineralized SOC derived from the recalcitrant carbon pool. Labile carbon fraction constitutes on average 0.4% of SOC across the three forest types and was rapidly digested by soil microbes in the early incubation stage. SOC mineralization markedly increased with soil moisture content, and correlated parabolically to temperature with the highest value at 15 °C. No significant interaction was detected among these variables in the present study.展开更多
Glyphosate is the most used herbicide in Argentina, accounting for 62% of the commercialized pesticides on the market. It is used as a weed controller in no-till systems, and it is also applied to various genetically ...Glyphosate is the most used herbicide in Argentina, accounting for 62% of the commercialized pesticides on the market. It is used as a weed controller in no-till systems, and it is also applied to various genetically modified crops ( e.g., soybean, corn, and cotton). Although it has a high solubility in water, it tends to adsorb and accumulate in agricultural soils. The main objectives of this work were to compare the dissipation of glyphosate and the accumulation of its metabolite aminomethylphosphonic acid (AMPA) over time in three soils from agricultural areas of Argentina under long-term management with no-till (NT) and conventional tillage (CT) practices. There were no differences in dissipation between NT and CT, indicating that the glyphosate-degrading microflora was not modified by the different tillage managements. Moreover, tillage practices did not alter the general soil properties;therefore, glyphosate bioavailability was not affected by NT or CT practice. Forty percent of the applied glyphosate was degraded within the first three days in all soils, indicating a fast initial dissipation rate. However, the dissipation rate considerably decreased over time, and the degradation kinetics followed a bi-exponential (or two-compartment) kinetic model. No differences were found between tillage practices. Dissipation was not related to the microbial activity measured as soil respiration. The fast decrease in the concentration of glyphosate at the beginning of the dissipation study was not reflected in an increase in the concentration of AMPA. The estimated half-lives for glyphosate ranged between 9 and 38 d. However, glyphosate bioavailability decreases over time, as it is strongly adsorbed to the soil matrix. This increases its residence time, which may lead to its accumulation in agricultural soils.展开更多
The maximum predicting error of the commonly used passive truncated mooring system method may reach 30%due to the difference of dynamic characteristics between the truncated and full-depth mooring line.In this paper,t...The maximum predicting error of the commonly used passive truncated mooring system method may reach 30%due to the difference of dynamic characteristics between the truncated and full-depth mooring line.In this paper,the experimental strategy called three-parameter(displacement,velocity and acceleration)active control method at the truncated point of mooring line is established to implement the synchronous equivalent of motion and force,and the realization of active truncated mooring system for model test is studied theoretically.The influences of threeparameter and one-parameter(displacement)active control strategies on the compensation effects are compared by numerical study.The results show that the established three-parameter active control method can feasibly realize the static and dynamic equivalent of truncated and full-depth mooring system,laying a good foundation for the following physical model test of active truncated mooring system.展开更多
This paper proposes a based on 3D-VLE （three-dimensional nonlinear viscoelastic theory） three-parameters viscoelastic model for studying the time-dependent behaviour of concrete filled steel tube （CFT） columns. Th...This paper proposes a based on 3D-VLE （three-dimensional nonlinear viscoelastic theory） three-parameters viscoelastic model for studying the time-dependent behaviour of concrete filled steel tube （CFT） columns. The method of 3D-VLE was developed to analyze the effects of concrete creep behavior on CFT structures. After the evaluation of the parameters in the proposed creep model, experimental measurements of two prestressed reinforced concrete beams were used to investigate the creep phenomenon of three CFT columns under long-term axial and eccentric load was investigated. The experimentally obtained time-dependent creep behaviour accorded well with the cu~＇es obtained from the proposed method. Many factors （such as ratio of long-term load to strength, slenderness ratio, steel ratio, and eccentricity ratio） were considered to obtain the regularity of influence of concrete creep on CFT structures. The analytical results can be consulted in the engineering practice and design.展开更多
In this paper,we study the dynamical behavior of a stochastic two-compartment model of B-cell chronic lymphocytic leukemia,which is perturbed by white noise.Firstly,by constructing suitable Lyapunov functions,we estab...In this paper,we study the dynamical behavior of a stochastic two-compartment model of B-cell chronic lymphocytic leukemia,which is perturbed by white noise.Firstly,by constructing suitable Lyapunov functions,we establish sufficient conditions for the existence of a unique ergodic stationary distribution.Then,conditions for extinction of the disease are derived.Furthermore,numerical simulations are presented for supporting the theoretical results.Our results show that large noise intensity may contribute to extinction of the disease.展开更多
Nano-TiO_(2) can remarkably increase lead(Pb)toxicity in aquatic organisms.However,the mechanism of this toxicity,additive or synergistic,is not well understood.To explore this mechanism,we inspected the role of nano-...Nano-TiO_(2) can remarkably increase lead(Pb)toxicity in aquatic organisms.However,the mechanism of this toxicity,additive or synergistic,is not well understood.To explore this mechanism,we inspected the role of nano-TiO_(2) in the toxicity of Pb on Ceriodaphnia dubia(C.dubia),a model water flea species typically used for ecotoxicity studies.The effect of algae,a diet for aquatic organisms,on the effect of this binary mixture was also investigated.A two-compartment toxicokinetic(TK)-toxicodynamic(TD)modeling approach was used to quantify the Pb toxicity under these complex conditions and to develop critical parameters for understanding the mechanism of toxicity.This twocompartment modeling approach adequately described the Pb accumulation in the gut and in the rest of the body tissue under different nano-TiO_(2) concentrations,with and without algae,and predicted the toxicity response of C.dubia.It indicated that increasing the nano-TiO_(2) concentration reduced the Pb tolerance level and concurrently increased the killing rate constant of C.dubia.Therefore,nano-TiO_(2) synergistically enhanced Pb toxicity.Algae remarkably reduced the toxicity of this binary mixture through reducing the Pb transfer rate to the body tissue and the killing rate,although it did not affect the Pb tolerance level.This two-compartment modeling approach is useful in understanding the role of nanoparticles when assessing the overall toxicity of nanoparticles and other toxic elements in the environment.展开更多
基金financially supported by the National Natural Science Foundation of China(No.U156405)the GRINM Youth Foundation funded project
文摘The inconsistency of lithium-ion cells degrades battery performance,lifetime and even safety.The complexity of the cell reaction mechanism causes an irregular asymmetrical distribution of various cell parameters,such as capacity and internal resistance,among others.In this study,the Newman electrochemical model was used to simulate the 1 C discharge curves of 100 LiMn2 O4 pouch cells with parameter variations typically produced in manufacturing processes,and the three-parameter Weibull probability model was used to analyze the dispersion and symmetry of the resulting discharge voltage distributions.The results showed that the dispersion of the voltage distribution was related to the rate of decrease in the discharge voltage,and the symmetry was related to the change in the rate of voltage decrease.The effect of the cells’capacity dominated the voltage distribution thermodynamically during discharge,and the phase transformation process significantly skewed the voltage distribution.The effects of the ohmic drop and polarization voltage on the voltage distribution were primarily kinetic.The presence of current returned the right-skewed voltage distribution caused by phase transformation to a more symmetrical distribution.Thus,the Weibull parameters elucidated the electrochemical behavior during the discharge process,and this method can guide the prediction and control of cell inconsistency,as well as detection and control strategies for cell management systems.
文摘A two-compartment model of the universe is proposed to further refine Albert Einstein’s insight into curvature of space and the energy tensor. The two compartments are energy contained by a shell prism. The model allows for a non-unification of fundamental forces with gravity resulting from the curvature of a space-time prism. Carrier forces travel within the prism and particles emerge from the prism. Giving a thickness to the manifold negates infinity and will allow solutions at both microscopic and cosmic levels. Geometry is the link between quantum mechanics and general relativity. Negative entropy, as proposed by Erwin Schrödinger, gives order to particles and the cosmic. The source of this energy is in the shell of the containment vessel. The acceleration of the expansion of the universe occurred when energy within the container transformed into mass, warping the space-time container and causing an explosion of the container. Star movement is explained by the surface tension of the prism of space-time.
基金National Natural Science Foundation of China(No.71371035)
文摘The two-parameter lognormal distribution is a variant of the normal distribution and the three-parameter lognormal distribution is an extension of the two-parameter lognormal distribution by introducing a location parameter. The Q-Q plot of the three-parameter lognormal distribution is widely used. To obtain the Q-Q plot one needs to iteratively try different values of the shape parameter and subjectively judge the linearity of the Q-Q plot. In this paper,a mathematical method was proposed to determine the value of the shape parameter so as to simplify the generation of the Q-Q plot. Then a new probability plot was proposed,which was more easily obtained and provided more accurate parameter estimates than the Q-Q plot. These are illustrated by three realworld examples.
基金Naitonal Natural Science Foundation of China Under Grant No.90815026Foundation of National Seismic Bureau Under Grant No.200808074
文摘Based on the consistency-viscoplastic constitutive model,the static William-Warnke model with three-parameters is modified and a consistency-viscoplastic William-Warnke model with three-parameters is developed that considers the effect of strain rates. Then,the tangent modulus of the consistency viscoplastic model is introduced and an implicit backward Elure iterative algorithm is developed. Comparisons between the numerical simulations and experimental data show that the consistency model properly provides the uniaxial and biaxial dynamic behaviors of concrete. To study the effect of strain rates on the dynamic response of concrete structures,the proposed model is used in the analysis of the dynamic response of a simply-supported beam and the results show that the strain rate has a significant effect on the displacement and stress magnitudes and distributions. Finally,the seismic responses of a 278 m high arch dam are obtained and compared by using the linear elastic model,as well as rate-independent and rate-dependent William-Warnke three-parameter models. The results indicate that the strain rate affects the first principal stresses,and the maximal equivalent viscoplastic strain rate of the arch dam. Numerical calculations and analyses reveal that considering the strain rate is important in the safety assessments of arch dams located in seismically active areas.
基金supported by the National Natural Science Foundation of China(Grant Nos.52375264 and 62376212).
文摘The power sector is an important factor in ensuring the development of the national economy.Scientific simulation and prediction of power consumption help achieve the balance between power generation and power consumption.In this paper,a Multi-strategy Hybrid Coati Optimizer(MCOA)is used to optimize the parameters of the three-parameter combinatorial optimization model TDGM(1,1,r,ξ,Csz)to realize the simulation and prediction of China's daily electricity consumption.Firstly,a novel MCOA is proposed in this paper,by making the following improvements to the Coati Optimization Algorithm(COA):(ⅰ)Introduce improved circle chaotic mapping strategy.(ⅱ)Fusing Aquila Optimizer,to enhance MCOA's exploration capabilities.(ⅲ)Adopt an adaptive optimal neighborhood jitter learning strategy.Effectively improve MCOA escape from local optimal solutions.(ⅳ)Incorporating Differential Evolution to enhance the diversity of the population.Secondly,the superiority of the MCOA algorithm is verified by comparing it with the newly proposed algorithm,the improved optimiza-tion algorithm,and the hybrid algorithm on the CEC2019 and CEC2020 test sets.Finally,in this paper,MCOA is used to optimize the parameters of TDGM(1,1,r,ξ,Csz),and this model is applied to forecast the daily electricity consumption in China and compared with the predictions of 14 models,including seven intelligent algorithm-optimized TDGM(1,1,r,ξ,Csz),and seven forecasting models.The experimental results show that the error of the proposed method is minimized,which verifies the validity of the proposed method.
基金Supported by National Basic Research Program of China(973 Program,Grant No.2013CB035042)the National Natural Science Foundation of China(Grant No.11672202)
文摘Cutterhead loads are the key mechanical parameters for the strength design of the full face hard rock tunnel boring machine(TBM).Due to the brittle rock-breaking mechanism,the excavation loads acting on cutters fluctuate strongly and show some randomness.The conventional method that using combinations of some special static loads to perform the strength design of TBM cutterhead may lead to strength failure during working practice.In this paper,a three-dimensional finite element model for coupled Cutterhead–Rock is developed to determine the cutterhead loads.Then the distribution characteristics and the influence factors of cutterhead loads are analyzed based on the numerical results.It is found that,as time changes,the normal and tangential forces acting on cutters and the total torque acting on the cutterhead approximately distribute log normally,while the total thrusts acting on the cutterhead approximately show a normal distribution.Furthermore,the statistical average values of cutterhead loads are proportional to the uniaxial compressive strength(UCS)of cutting rocks.The values also change with the penetration and the diameter of cutterhead following a power function.Based on these findings,we propose a three-parameter model for the mean of cutterhead loads and a method of generating the random cutter forces.Then the strength properties of a typical cutterhead are analyzed in detail using loads generated by the new method.The optimized cutterhead has been successfully applied in engineering.The method in this paper may provide a useful reference for the strength design of TBM cutterhead.
基金financially supported by the Fundamental Research Funds for the Central Universities(Grant No.YX2014-10)the Normal Sustainability Fund for the Taiyueshan Long-Term Forest Ecology Research Station(2017-LYPT-DW-148)
文摘Background: The large potential of the soil organic carbon(SOC) pool to sequester CO2from the atmosphere could greatly ameliorate the effect of future climate change. However, the quantity of carbon stored in terrestrial soils largely depends upon the magnitude of SOC mineralization. SOC mineralization constitutes an important part of the carbon cycle, and is driven by many biophysical variables, such as temperature and moisture.Methods: Soil samples of a pine forest, an oak forest, and a pine and oak mixed forest were incubated for 387 days under conditions with six temperature settings(5 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C) and three levels of soil moisture content(SMC, 30%, 60%, 90%). The instantaneous rate of mineralized SOC was periodically and automatically measured using a Li-Cor CO2analyzer. Based on the measured amount of mineralized SOC,carbon fractions were estimated separately via first-order kinetic one-and two-compartment models.Results: During the 387 day incubation experiment, accumulative mineralized carbon ranged from 22.89 mg carbon(C) ·g-1SOC at 30 °C and 30% SMC for the mixed forest to 109.20 mg C·g-1SOC at 15 °C and 90% SMC for the oak forest. Mineralized recalcitrant carbon varied from 18.48 mg C·g-1SOC at 30 °C and 30% SMC for the mixed forest to 104.98 mg C·g-1SOC at 15 °C and 90% SMC for the oak forest, and contributed at least 80% to total mineralized carbon.Conclusions: Based on the results of this experiment, the soil organic matter of the pure broadleaved forest is more vulnerable to soil microbial degradation in northern China; most of the amount of the mineralized SOC derived from the recalcitrant carbon pool. Labile carbon fraction constitutes on average 0.4% of SOC across the three forest types and was rapidly digested by soil microbes in the early incubation stage. SOC mineralization markedly increased with soil moisture content, and correlated parabolically to temperature with the highest value at 15 °C. No significant interaction was detected among these variables in the present study.
基金supported by the Instituto Nacional de Tecnologa Agropecuaria of Argentina(INTA PNSUELO 1134044)the Fondo Para la Investigacion Cientfica y Tecnologica of Argentina(PICT 448)
文摘Glyphosate is the most used herbicide in Argentina, accounting for 62% of the commercialized pesticides on the market. It is used as a weed controller in no-till systems, and it is also applied to various genetically modified crops ( e.g., soybean, corn, and cotton). Although it has a high solubility in water, it tends to adsorb and accumulate in agricultural soils. The main objectives of this work were to compare the dissipation of glyphosate and the accumulation of its metabolite aminomethylphosphonic acid (AMPA) over time in three soils from agricultural areas of Argentina under long-term management with no-till (NT) and conventional tillage (CT) practices. There were no differences in dissipation between NT and CT, indicating that the glyphosate-degrading microflora was not modified by the different tillage managements. Moreover, tillage practices did not alter the general soil properties;therefore, glyphosate bioavailability was not affected by NT or CT practice. Forty percent of the applied glyphosate was degraded within the first three days in all soils, indicating a fast initial dissipation rate. However, the dissipation rate considerably decreased over time, and the degradation kinetics followed a bi-exponential (or two-compartment) kinetic model. No differences were found between tillage practices. Dissipation was not related to the microbial activity measured as soil respiration. The fast decrease in the concentration of glyphosate at the beginning of the dissipation study was not reflected in an increase in the concentration of AMPA. The estimated half-lives for glyphosate ranged between 9 and 38 d. However, glyphosate bioavailability decreases over time, as it is strongly adsorbed to the soil matrix. This increases its residence time, which may lead to its accumulation in agricultural soils.
基金financially supported by the National Natural Science Foundation of China(Grant No.51979030)the Natural Science Foundation of Liaoning Province(Grant No.2021-KF-16-01)the Fundamental Research Funds for the Central Universities。
文摘The maximum predicting error of the commonly used passive truncated mooring system method may reach 30%due to the difference of dynamic characteristics between the truncated and full-depth mooring line.In this paper,the experimental strategy called three-parameter(displacement,velocity and acceleration)active control method at the truncated point of mooring line is established to implement the synchronous equivalent of motion and force,and the realization of active truncated mooring system for model test is studied theoretically.The influences of threeparameter and one-parameter(displacement)active control strategies on the compensation effects are compared by numerical study.The results show that the established three-parameter active control method can feasibly realize the static and dynamic equivalent of truncated and full-depth mooring system,laying a good foundation for the following physical model test of active truncated mooring system.
文摘This paper proposes a based on 3D-VLE （three-dimensional nonlinear viscoelastic theory） three-parameters viscoelastic model for studying the time-dependent behaviour of concrete filled steel tube （CFT） columns. The method of 3D-VLE was developed to analyze the effects of concrete creep behavior on CFT structures. After the evaluation of the parameters in the proposed creep model, experimental measurements of two prestressed reinforced concrete beams were used to investigate the creep phenomenon of three CFT columns under long-term axial and eccentric load was investigated. The experimentally obtained time-dependent creep behaviour accorded well with the cu~＇es obtained from the proposed method. Many factors （such as ratio of long-term load to strength, slenderness ratio, steel ratio, and eccentricity ratio） were considered to obtain the regularity of influence of concrete creep on CFT structures. The analytical results can be consulted in the engineering practice and design.
基金This work is supported by the National Natural Science Foundation of China(No.11871473)Natural Science Foundation of Shandong Province(No.ZR2019MA010)Science and Technology Research Project of Jilin Provincial Department of Education of China(No.JJKH20180462KJ).
文摘In this paper,we study the dynamical behavior of a stochastic two-compartment model of B-cell chronic lymphocytic leukemia,which is perturbed by white noise.Firstly,by constructing suitable Lyapunov functions,we establish sufficient conditions for the existence of a unique ergodic stationary distribution.Then,conditions for extinction of the disease are derived.Furthermore,numerical simulations are presented for supporting the theoretical results.Our results show that large noise intensity may contribute to extinction of the disease.
文摘Nano-TiO_(2) can remarkably increase lead(Pb)toxicity in aquatic organisms.However,the mechanism of this toxicity,additive or synergistic,is not well understood.To explore this mechanism,we inspected the role of nano-TiO_(2) in the toxicity of Pb on Ceriodaphnia dubia(C.dubia),a model water flea species typically used for ecotoxicity studies.The effect of algae,a diet for aquatic organisms,on the effect of this binary mixture was also investigated.A two-compartment toxicokinetic(TK)-toxicodynamic(TD)modeling approach was used to quantify the Pb toxicity under these complex conditions and to develop critical parameters for understanding the mechanism of toxicity.This twocompartment modeling approach adequately described the Pb accumulation in the gut and in the rest of the body tissue under different nano-TiO_(2) concentrations,with and without algae,and predicted the toxicity response of C.dubia.It indicated that increasing the nano-TiO_(2) concentration reduced the Pb tolerance level and concurrently increased the killing rate constant of C.dubia.Therefore,nano-TiO_(2) synergistically enhanced Pb toxicity.Algae remarkably reduced the toxicity of this binary mixture through reducing the Pb transfer rate to the body tissue and the killing rate,although it did not affect the Pb tolerance level.This two-compartment modeling approach is useful in understanding the role of nanoparticles when assessing the overall toxicity of nanoparticles and other toxic elements in the environment.
