In China,the target setting on loading rate of domestic equipment for shipbuilding industry has not been studied from a perspective of an optimization problem.Based on the constant elasticity of substitution productio...In China,the target setting on loading rate of domestic equipment for shipbuilding industry has not been studied from a perspective of an optimization problem.Based on the constant elasticity of substitution production function,a localization rate model for shipbuilding industry is established to investigate the government's trade-off between the interest of shipbuilding industry and that of ship supporting industry and to set the optimal localization rate.The results show that the market capacity has a significant effect on localization rate.In particular,when the market capacity is too small,the optimal localization rate is zero.When the market capacity is too large,the optimal localization rate is one.When the market capacity is in a certain range,a regular localization rate target exists.Moreover,the optimal localization rate could be affected by the technology gap and prices of domestic and foreign marine equipments.When the market capacity is large and the technology gap between domestic and foreign marine equipments is small,or the price of domestic equipment is too low,a higher localization rate target should be set.Finally,the substitutability of domestic and foreign equipments affects the optimal set of localization rate.If the substitutability of domestic and foreign equipments is too low,the improvement of localization rate caused by technological progress or price reduction of domestic equipment will be limited.This study provides several significant policy suggestions on dynamic adjustment of localization rate,classified implementation,and core technology mastering.展开更多
The stress path characteristics of surrounding rock in the formation of gob were analyzed and the unloading was solved.Taking Chengchao Iron Mine as the engineering background,the model for analyzing the instability o...The stress path characteristics of surrounding rock in the formation of gob were analyzed and the unloading was solved.Taking Chengchao Iron Mine as the engineering background,the model for analyzing the instability of deep gob was established based on the mechanism of stress relief in deep mining.The energy evolution law was analyzed by introducing the local energy release rate index(LERR),and the energy criterion of the instability of surrounding rock was established based on the cusp catastrophe theory.The results show that the evolution equation of the local energy release of the surrounding rock is a quartic function with one unknown and the release rate increases gradually during the mining process.The calculation results show that the gob is stable.The LERR per unit volume of the bottom structure is relatively smaller which means that the stability is better.The LERR distribution showed that there was main energy release in the horizontal direction and energy concentration in the vertical direction which meets the characteristics of deep mining.In summary,this model could effectively calculate the stability of surrounding rock in the formation of gob.The LERR could reflect the dynamic process of energy release,transfer and dissipation and that provided an important reference for the study of the stability of deep mined out area.展开更多
An artificial localized corrosion system is assembled and some parameters related to the localized corrosion in active dissolution state (i.e., non-passive state) have been studied. The results showed that the develop...An artificial localized corrosion system is assembled and some parameters related to the localized corrosion in active dissolution state (i.e., non-passive state) have been studied. The results showed that the developed electrochemical system can satisfactorily imitate a naturally formed localized corrosion and the coupling current can indicate the maximum localized propagating rate. In this artificial system, the anodic dissolution reaction followed the auto-catalytic mechanism. The localized corrosion current density was dependent on the area ratio R of the cathode to the occluded anode. While R was equal to or more than 6, the coupling current reached at a maximum value and did not alter with the increase in R-value. Therefore, R=7 is chosen as one of these optimum parameters used in constructing the system, with which the biggest galvanic current might be obtained. In contrast, the thickness of the polymer filler separating the occluded anode area from the bulk electrolyte solution and the volume of the occluded anode area did not affect the corrosion current obviously. They might affect the response time to approach a steady state.展开更多
This article investigates the colloidal study for water and ethylene glycol based nanofluids.The effects of Lorentz forces and thermal radiation are considered.The process of non-dimensionalities of governing equation...This article investigates the colloidal study for water and ethylene glycol based nanofluids.The effects of Lorentz forces and thermal radiation are considered.The process of non-dimensionalities of governing equations is carried out successfully by means of similarity variables.Then,the resultant nonlinear nature of flow model is treated numerically via Runge-Kutta scheme.The characteristics of various pertinent flow parameters on the velocity,temperature,streamlines and isotherms are discussed graphically.It is inspected that the Lorentz forces favors the rotational velocity and rotational parameter opposes it.Intensification in the nanofluids temperature is observed for volumetric fraction and thermal radiation parameter and dominating trend is noted for γ-aluminum nanofluid.Furthermore,for higher rotational parameter,reverse flow is investigated.To provoke the validity of the present work,comparison between current and literature results is presented which shows an excellent agreement.It is examined that rotation favors the velocity of the fluid and more radiative fluid enhances the fluid temperature.Moreover,it is inspected that upturns in volumetric fraction improves the thermal and electrical conductivities.展开更多
For the improved two-sided projected quasi-Newton algorithms, which were presented in PartI, we prove in this paper that they are locally one-step or two-step superlinearly convergent. Numerical tests are reported the...For the improved two-sided projected quasi-Newton algorithms, which were presented in PartI, we prove in this paper that they are locally one-step or two-step superlinearly convergent. Numerical tests are reported thereafter. Results by solving a set of typical problems selectedfrom literature have demonstrated the extreme importance of these modifications in making Nocedal& Overton's original methon practical. Furthermore, these results show that the improved algoritnmsare very competitive in comparison with some highly praised sequential quadratic programmingmethods.展开更多
Air conditioning ventilation ducts are widely used in contemporary buildings.The change of airflow direction in the ducts local components can easily lead to the deposition of particles,which can easily form a seconda...Air conditioning ventilation ducts are widely used in contemporary buildings.The change of airflow direction in the ducts local components can easily lead to the deposition of particles,which can easily form a secondary source of indoor air pollution and have an adverse effect on human health.Based on this,this paper utilizes the existing experimental data to validate the numerical simulation.The Reynolds stress turbulence model combined with the method of enhanced wall function was used to investigate the deposition characteristics of fine particles in different local components.For the first time,local deposition rates and deposition hotspots were proposed to analyze the simulation results.The results show that the local deposition rate of the particles with a particle size of 1μm do not differ much on each wall surface,and the particles are deposited more uniformly on each wall at the local components,with a difference of less than 10%,and the maximum local deposition rate is on the outer wall of the local components.When the particle size is larger than 10μm,the local deposition rate on the outer wall of the local component increases significantly,with a maximum increase of 23.3%(compared to 5μm particles),and the maximum local deposition rate increases slowly with increasing air velocity,with a maximum increase of less than 8%.The effect of increasing particle size on the maximum local deposition rate is much greater than the increase in air velocity.With the increase of air velocity and particle size,the deposition hotspots of both the 90°bend and the T-type tee duct migrate to the middle of the wall,and the deposition hotspots of the 4-way duct migrate to the inside of the wall.展开更多
In this paper,we study a stochastic Newton method for nonlinear equations,whose exact function information is difficult to obtain while only stochastic approximations are available.At each iteration of the proposed al...In this paper,we study a stochastic Newton method for nonlinear equations,whose exact function information is difficult to obtain while only stochastic approximations are available.At each iteration of the proposed algorithm,an inexact Newton step is first computed based on stochastic zeroth-and first-order oracles.To encourage the possible reduction of the optimality error,we then take the unit step size if it is acceptable by an inexact Armijo line search condition.Otherwise,a small step size will be taken to help induce desired good properties.Then we investigate convergence properties of the proposed algorithm and obtain the almost sure global convergence under certain conditions.We also explore the computational complexities to find an approximate solution in terms of calls to stochastic zeroth-and first-order oracles,when the proposed algorithm returns a randomly chosen output.Furthermore,we analyze the local convergence properties of the algorithm and establish the local convergence rate in high probability.At last we present preliminary numerical tests and the results demonstrate the promising performances of the proposed algorithm.展开更多
The velocity profile around cells in a flow chamber coated with the immobilized protein and the endothelial cells is studied using the micro particle image velocimetry（PIV）. The main purpose is to study the effect o...The velocity profile around cells in a flow chamber coated with the immobilized protein and the endothelial cells is studied using the micro particle image velocimetry（PIV）. The main purpose is to study the effect of the endothelial cells on the local hydrodynamic environment and the local shear rates above a single polymorphonuclear neutrophil（PMN） and a melanoma cell when they adhere to different immobilized protein substrates. Micro-PIV images are taken in the top-view and the side-view under 10 X and 40 X objective lens and the ensemble correlation method is used to analyze the data. The results show that the endothelial monolayer has changed the patterns of the flow velocity profile of the side-view flow on the chamber bottom, and also increased the wall shear rates. The melanoma cells adhered on the immobilized fibrin disturb the local flow more than those adhered on the immobilized fibrinogen, but one sees no significant difference between the local shear rates above the PMNs adhered on the immobilized fibrinogen and those above the PMNs adhered on the immobilized fibrin.展开更多
基金supported in part by National Key R&D Program of China(2019YFB2101804)the National Natural Science Foundation of China(NSFC)under Grants Nos.71725002,72021001,U21B20102,72174186.
文摘In China,the target setting on loading rate of domestic equipment for shipbuilding industry has not been studied from a perspective of an optimization problem.Based on the constant elasticity of substitution production function,a localization rate model for shipbuilding industry is established to investigate the government's trade-off between the interest of shipbuilding industry and that of ship supporting industry and to set the optimal localization rate.The results show that the market capacity has a significant effect on localization rate.In particular,when the market capacity is too small,the optimal localization rate is zero.When the market capacity is too large,the optimal localization rate is one.When the market capacity is in a certain range,a regular localization rate target exists.Moreover,the optimal localization rate could be affected by the technology gap and prices of domestic and foreign marine equipments.When the market capacity is large and the technology gap between domestic and foreign marine equipments is small,or the price of domestic equipment is too low,a higher localization rate target should be set.Finally,the substitutability of domestic and foreign equipments affects the optimal set of localization rate.If the substitutability of domestic and foreign equipments is too low,the improvement of localization rate caused by technological progress or price reduction of domestic equipment will be limited.This study provides several significant policy suggestions on dynamic adjustment of localization rate,classified implementation,and core technology mastering.
基金provided by the National Natural Science Foundation of China(No.5137403)the Fundamental Research Funds for the Central Universities(No.FRF-TP-15-042A1)
文摘The stress path characteristics of surrounding rock in the formation of gob were analyzed and the unloading was solved.Taking Chengchao Iron Mine as the engineering background,the model for analyzing the instability of deep gob was established based on the mechanism of stress relief in deep mining.The energy evolution law was analyzed by introducing the local energy release rate index(LERR),and the energy criterion of the instability of surrounding rock was established based on the cusp catastrophe theory.The results show that the evolution equation of the local energy release of the surrounding rock is a quartic function with one unknown and the release rate increases gradually during the mining process.The calculation results show that the gob is stable.The LERR per unit volume of the bottom structure is relatively smaller which means that the stability is better.The LERR distribution showed that there was main energy release in the horizontal direction and energy concentration in the vertical direction which meets the characteristics of deep mining.In summary,this model could effectively calculate the stability of surrounding rock in the formation of gob.The LERR could reflect the dynamic process of energy release,transfer and dissipation and that provided an important reference for the study of the stability of deep mined out area.
文摘An artificial localized corrosion system is assembled and some parameters related to the localized corrosion in active dissolution state (i.e., non-passive state) have been studied. The results showed that the developed electrochemical system can satisfactorily imitate a naturally formed localized corrosion and the coupling current can indicate the maximum localized propagating rate. In this artificial system, the anodic dissolution reaction followed the auto-catalytic mechanism. The localized corrosion current density was dependent on the area ratio R of the cathode to the occluded anode. While R was equal to or more than 6, the coupling current reached at a maximum value and did not alter with the increase in R-value. Therefore, R=7 is chosen as one of these optimum parameters used in constructing the system, with which the biggest galvanic current might be obtained. In contrast, the thickness of the polymer filler separating the occluded anode area from the bulk electrolyte solution and the volume of the occluded anode area did not affect the corrosion current obviously. They might affect the response time to approach a steady state.
文摘This article investigates the colloidal study for water and ethylene glycol based nanofluids.The effects of Lorentz forces and thermal radiation are considered.The process of non-dimensionalities of governing equations is carried out successfully by means of similarity variables.Then,the resultant nonlinear nature of flow model is treated numerically via Runge-Kutta scheme.The characteristics of various pertinent flow parameters on the velocity,temperature,streamlines and isotherms are discussed graphically.It is inspected that the Lorentz forces favors the rotational velocity and rotational parameter opposes it.Intensification in the nanofluids temperature is observed for volumetric fraction and thermal radiation parameter and dominating trend is noted for γ-aluminum nanofluid.Furthermore,for higher rotational parameter,reverse flow is investigated.To provoke the validity of the present work,comparison between current and literature results is presented which shows an excellent agreement.It is examined that rotation favors the velocity of the fluid and more radiative fluid enhances the fluid temperature.Moreover,it is inspected that upturns in volumetric fraction improves the thermal and electrical conductivities.
基金This research was supported in part by the National Natural Science Foundation of china
文摘For the improved two-sided projected quasi-Newton algorithms, which were presented in PartI, we prove in this paper that they are locally one-step or two-step superlinearly convergent. Numerical tests are reported thereafter. Results by solving a set of typical problems selectedfrom literature have demonstrated the extreme importance of these modifications in making Nocedal& Overton's original methon practical. Furthermore, these results show that the improved algoritnmsare very competitive in comparison with some highly praised sequential quadratic programmingmethods.
基金supported by the National Natural Science Foundation of China(Grant No.52108099)the Natural Science Foundation Youth Program of Hunan Province,China(Grant No.2022JJ40443)the Excellent Youth Project of Education Bureau of Hunan Province,China(Grant No.21B0134).
文摘Air conditioning ventilation ducts are widely used in contemporary buildings.The change of airflow direction in the ducts local components can easily lead to the deposition of particles,which can easily form a secondary source of indoor air pollution and have an adverse effect on human health.Based on this,this paper utilizes the existing experimental data to validate the numerical simulation.The Reynolds stress turbulence model combined with the method of enhanced wall function was used to investigate the deposition characteristics of fine particles in different local components.For the first time,local deposition rates and deposition hotspots were proposed to analyze the simulation results.The results show that the local deposition rate of the particles with a particle size of 1μm do not differ much on each wall surface,and the particles are deposited more uniformly on each wall at the local components,with a difference of less than 10%,and the maximum local deposition rate is on the outer wall of the local components.When the particle size is larger than 10μm,the local deposition rate on the outer wall of the local component increases significantly,with a maximum increase of 23.3%(compared to 5μm particles),and the maximum local deposition rate increases slowly with increasing air velocity,with a maximum increase of less than 8%.The effect of increasing particle size on the maximum local deposition rate is much greater than the increase in air velocity.With the increase of air velocity and particle size,the deposition hotspots of both the 90°bend and the T-type tee duct migrate to the middle of the wall,and the deposition hotspots of the 4-way duct migrate to the inside of the wall.
基金supported by the National Natural Science Foundation of China(Nos.11731013,11871453 and 11971089)Young Elite Scientists Sponsorship Program by CAST(No.2018QNRC001)+1 种基金Youth Innovation Promotion Association,CASFundamental Research Funds for the Central Universities,UCAS.
文摘In this paper,we study a stochastic Newton method for nonlinear equations,whose exact function information is difficult to obtain while only stochastic approximations are available.At each iteration of the proposed algorithm,an inexact Newton step is first computed based on stochastic zeroth-and first-order oracles.To encourage the possible reduction of the optimality error,we then take the unit step size if it is acceptable by an inexact Armijo line search condition.Otherwise,a small step size will be taken to help induce desired good properties.Then we investigate convergence properties of the proposed algorithm and obtain the almost sure global convergence under certain conditions.We also explore the computational complexities to find an approximate solution in terms of calls to stochastic zeroth-and first-order oracles,when the proposed algorithm returns a randomly chosen output.Furthermore,we analyze the local convergence properties of the algorithm and establish the local convergence rate in high probability.At last we present preliminary numerical tests and the results demonstrate the promising performances of the proposed algorithm.
基金Project supported by the National Institute of Health(NIH,USA,Grant No.CA-125707)the National Science Foundation(NSF,USA,Grant No.CBET-0729091)+1 种基金the National Natural Science Foundation of China(Grant Nos.11302129,11432006 and 31170887)the Fellowship from Chinese Scholarship Council
文摘The velocity profile around cells in a flow chamber coated with the immobilized protein and the endothelial cells is studied using the micro particle image velocimetry（PIV）. The main purpose is to study the effect of the endothelial cells on the local hydrodynamic environment and the local shear rates above a single polymorphonuclear neutrophil（PMN） and a melanoma cell when they adhere to different immobilized protein substrates. Micro-PIV images are taken in the top-view and the side-view under 10 X and 40 X objective lens and the ensemble correlation method is used to analyze the data. The results show that the endothelial monolayer has changed the patterns of the flow velocity profile of the side-view flow on the chamber bottom, and also increased the wall shear rates. The melanoma cells adhered on the immobilized fibrin disturb the local flow more than those adhered on the immobilized fibrinogen, but one sees no significant difference between the local shear rates above the PMNs adhered on the immobilized fibrinogen and those above the PMNs adhered on the immobilized fibrin.
