In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hy...In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hydraulic fractures in layered porous reservoirs with modulus contrast.The coupled hydromechanical model is first verified against an analytical solution and a laboratory experiment.Then,the fracture geometry(e.g.height,aperture,and area)and fluid pressure evolutions of multiple hydraulic fractures placed in a porous reservoir interbedded with alternating stiff and soft layers are investigated using the model.The stress and pore pressure distributions within the layered reservoir during fluid injection are also presented.The simulation results reveal that stress umbrellas are easily to form among multiple hydraulic fractures’tips when propagating in soft layers,which impedes the simultaneous height growth.It is also observed that the impediment effect of soft layer is much more significant in the fractures suppressed by the preferential growth of adjoining fractures.After that,the combined effect of in situ stress ratio and fracturing spacing on the multi-fracture height growth is presented,and the results elucidate the influence of in situ stress ratio on the height growth behavior depending on the fracture spacing.Finally,it is found that the inclusion of soft layers changes the aperture distribution of outmost and interior hydraulic fractures.The results obtained from this study may provide some insights on the understanding of hydraulic fracture height containment observed in filed.展开更多
It was tried to prepare the microcapsules containing grape polyphenol with the spray drying method followed by the layer-by-layer method. As grape polyphenol was water soluble, the spray drying method was adopted to o...It was tried to prepare the microcapsules containing grape polyphenol with the spray drying method followed by the layer-by-layer method. As grape polyphenol was water soluble, the spray drying method was adopted to obtain the higher content. As the shell material of the first microcapsules prepared by the spray drying method, palmitic acid with the melting point of 60°C was adopted in order to prevent grape polyphenol from dissolution into water. As the shell material of the second microcapsules prepared by the layer-by-layer method, chitosan was used to coat the first microcapsules and to give the microcapsules alcohol resistance. In the experiment, the spray drying conditions such as the inlet temperature and the spraying pressure, the oil soluble surfactant species and the chitosan concentration were changed. The mean diameters of microcapsules could be controlled in the range from 5 μm to 35 μm by changing the spraying pressure and the inlet temperature. The yield of microcapsules and the microencapsulation efficiency over 50% could be obtained under the conditions of P = 1.0 kgf/cm2 and Tin = 100°C. Furthermore, the microencapsulation efficiency could be increased by adding the oil soluble surfactant with the larger HLB value. Coating with chitosan could considerably increase alcohol resistance.展开更多
As a promising optical and piezoelectric crystal,efficient growth of LGN single crystal is crucial for its practical applications.Herein,a langanite(La_(3)Ga_(5.5)Nb_(0.5)O_(14),LGN)crystal with high quality was succe...As a promising optical and piezoelectric crystal,efficient growth of LGN single crystal is crucial for its practical applications.Herein,a langanite(La_(3)Ga_(5.5)Nb_(0.5)O_(14),LGN)crystal with high quality was successfully grown by the Bridgman method along the Z direction.In order to prepare high-purity polycrystalline precursors for LGN crystal growth,the sintering conditions of LGN polycrystalline precursors were studied in detail.The melting point of LGN was also measured to provide a reference for the crystal growth temperature.For the[001]oriented wafer,the full width at half maximum(EWHM)value of the nigh-resolution X-ray diffraction(HRXRD)analysis is 38.52",demonstrating that the LGN crystal exhibits excellent crystalline quality.In addition,we also measured the thermal properties and transmission spectrum of the as-grown LGN crystal.It is found that the absorption peak at 1.85μm of the LGN crystal grown in air using the Bridgman method disappears compared with previous reports(grown in N_(2+)(1-3)vol%O_(2)atmosphere),which is attributed to the oxygen-enriched growth environment.Similar phenomenon also occurs in other LGS-type disordered crystals.It is believed that these findings may expand the potential applications of LGS series crystals at 1.85μm.展开更多
In this paper,we study high energy normalized solutions for the following Schr?dinger equation{-Δu+V(x)u+λu=f(u),in R^(2),∫_(R^(2))|u|^(2)dx=c,where c>0,λ∈R will appear as a Lagrange multiplier,V(x)=ω|x|2 rep...In this paper,we study high energy normalized solutions for the following Schr?dinger equation{-Δu+V(x)u+λu=f(u),in R^(2),∫_(R^(2))|u|^(2)dx=c,where c>0,λ∈R will appear as a Lagrange multiplier,V(x)=ω|x|2 represents a trapping potential,and f has an exponential critical growth.Under the appropriate assumptions of f,we have obtained the existence of normalized solutions to the above Schr?dinger equation by introducing a variational method.And these solutions are also high energy solutions with positive energy.展开更多
By using the Ljusternik-Schnirelmann category and variational method,we s-tudy the existence,multiplicity and concentration of solutions to the fractional Schrodinger equation with potentials competition as follows,ε...By using the Ljusternik-Schnirelmann category and variational method,we s-tudy the existence,multiplicity and concentration of solutions to the fractional Schrodinger equation with potentials competition as follows,ε^(N)(-△)^(s)N/sμ+V(x)|μ|^(N/s-2μ)=Q(x)h(μ)in R^(N),where ε>0 is a parameter,s ∈(0,1),2≤p<+oo and N=ps.The nonlinear term h is a diferentiable function with exponential critical growth,the absorption potential V and the reaction potential Q are continuous functions.展开更多
A mathematical model combined projection algorithm with phase-field method was applied. The adaptive finite element method was adopted to solve the model based on the non-uniform grid, and the behavior of dendritic gr...A mathematical model combined projection algorithm with phase-field method was applied. The adaptive finite element method was adopted to solve the model based on the non-uniform grid, and the behavior of dendritic growth was simulated from undercooled nickel melt under the forced flow. The simulation results show that the asymmetry behavior of the dendritic growth is caused by the forced flow. When the flow velocity is less than the critical value, the asymmetry of dendrite is little influenced by the forced flow. Once the flow velocity reaches or exceeds the critical value, the controlling factor of dendrite growth gradually changes from thermal diffusion to convection. With the increase of the flow velocity, the deflection angle towards upstream direction of the primary dendrite stem becomes larger. The effect of the dendrite growth on the flow field of the melt is apparent. With the increase of the dendrite size, the vortex is present in the downstream regions, and the vortex region is gradually enlarged. Dendrite tips appear to remelt. In addition, the adaptive finite element method can reduce CPU running time by one order of magnitude compared with uniform grid method, and the speed-up ratio is proportional to the size of computational domain.展开更多
The research explored effects of cultivation methods on growth, yield and quality of cassava. The results showed that the mulching treatment by direct seed- ing, the mulching treatment by transplanting, and the expose...The research explored effects of cultivation methods on growth, yield and quality of cassava. The results showed that the mulching treatment by direct seed- ing, the mulching treatment by transplanting, and the exposed treatment by trans- planting performed excellently in bringing seedling stage forward, improving germina- tion rate, yield and quality. For example, seedling emergence stages were 36, 31 and 31 d earlier; germination rates improved by 19.24%, 14.29% and 14.29%; yields grew by 41.98%, 26.72% and 11.45%; starch contents increased by 3.50%, 2.10% and 1.40%, respectively. Therefore, cassava in the mulching treatment by direct seeding is characterized by earlier seedling emergence stage, high germination rate, high yield and quality.展开更多
In order to find the test cube for industrial robots as specified by ISO 9283, a seed cube is grown up in an irregular working space of the robot, provided that the corners of the cube do not exceed the boundary of t...In order to find the test cube for industrial robots as specified by ISO 9283, a seed cube is grown up in an irregular working space of the robot, provided that the corners of the cube do not exceed the boundary of the working space. All possible cubes are searched, and the cube with the maximum volume is selected. The calculation examples show that the method of growth can be used for a variety of industrial robots. The method of growth can determine the test cube and test points of irregular working space according to ISO 9283, and can avoid blindness and randomness in the selection of test points.展开更多
The growth interfaces of CdMnTe（CMT） crystals grown by traveling heater method（THM） were studied. Two types of polycrystalline CMT feed ingots synthesized in a traditional rocking furnace and vertical Bridgman（VB...The growth interfaces of CdMnTe（CMT） crystals grown by traveling heater method（THM） were studied. Two types of polycrystalline CMT feed ingots synthesized in a traditional rocking furnace and vertical Bridgman（VB） furnace were adopted in THM growth, and the effects of the polycrystalline feed on the growth interface were revealed. The morphology of the growth interface of CMT crystal（CMT2） grown from the feed by vertical Bridgman was smoother with lower curvature compared with that of CMT crystal（CMT1） from the feed by rocking furnace. The radial Mn composition and Te inclusion distribution of the CMT wafers were analyzed and correlated to the growth interface. The Mn segregation along the radial direction and Te inclusion density of CMT2 were lower than those of CMT1. The VB method synthesized polycrystalline feed could improve the growth interface morphology, which is beneficial for decreasing the Te inclusions and Mn segregation in CMT wafers.展开更多
Lithium secondary batteries（LSBs） with high energy densities need to be further developed for future applications in portable electronic devices, electric vehicles, hybrid electric vehicles and smart grids. Lithium ...Lithium secondary batteries（LSBs） with high energy densities need to be further developed for future applications in portable electronic devices, electric vehicles, hybrid electric vehicles and smart grids. Lithium metal is the most promising electrode for next-generation rechargeable batteries. However, the formation of lithium dendrite on the anode surface leads to serious safety concerns and low coulombic efficiency.Recently, researchers have made great efforts and significant progresses to solve these problems. Here we review the growth mechanism and suppression method of lithium dendrite for LSBs’ anode protection. We also establish the relationship between the growth mechanism and suppression method. The research direction for building better LSBs is given by comparing the advantages and disadvantages of these methods based on the growth mechanism.展开更多
The application of the adaptive growth method is limited because several key techniques during the design process need manual intervention of designers. Key techniques of the method including the ground structure cons...The application of the adaptive growth method is limited because several key techniques during the design process need manual intervention of designers. Key techniques of the method including the ground structure construction and seed selection are studied, so as to make it possible to improve the effectiveness and applicability of the adaptive growth method in stiffener layout design optimization of plates and shells. Three schemes of ground structures, which are comprised by different shell elements and beam elements, are proposed. It is found that the main stiffener layouts resulted from different ground structures are almost the same, but the ground structure comprised by 8-nodes shell elements and both 3-nodes and 2-nodes beam elements can result in clearest stiffener layout, and has good adaptability and low computational cost. An automatic seed selection approach is proposed, which is based on such selection rules that the seeds should be positioned on where the structural strain energy is great for the minimum compliance problem, and satisfy the dispersancy requirement. The adaptive growth method with the suggested key techniques is integrated into an ANSYS-based program, which provides a design tool for the stiffener layout design optimization of plates and shells. Typical design examples, including plate and shell structures to achieve minimum compliance and maximum bulking stability are illustrated. In addition, as a practical mechanical structural design example, the stiffener layout of an inlet structure for a large-scale electrostatic precipitator is also demonstrated. The design results show that the adaptive growth method integrated with the suggested key techniques can effectively and flexibly deal with stiffener layout design problem for plates and shells with complex geometrical shape and loading conditions to achieve various design objectives, thus it provides a new solution method for engineering structural topology design optimization.展开更多
To predict the dendrite morphology and microstructure evolution in the solidification of molten metal,numerically,lattice Boltzmann method(LBM)-cellular automata(CA)model has been developed by integrating the LBM to s...To predict the dendrite morphology and microstructure evolution in the solidification of molten metal,numerically,lattice Boltzmann method(LBM)-cellular automata(CA)model has been developed by integrating the LBM to solve the mass transport by diffusion and convection during solidification and the CA to determine the phase transformation with respect to the solid fraction based on the local equilibrium theory.It is successfully validated with analytic solutions such as Lipton-Glicksman-Kurz(LGK)model in static melt,and Oseen-Ivantsov solution under the fluid flow conditions in terms of tip radius and velocity of the dendrite growth.The proposed LBM-CA model does not only describe different types of dendrite formations with respect to various solidification conditions such as temperature gradient and growth rate,but also predict the primary dendrite arm spacing(PDAS)and the secondary dendrite arm spacing(SDAS),quantitatively,in directional solidification(DS)experiment with Ni-based superalloy.展开更多
The population balance modeling is regarded as a universally accepted mathematical framework for dynamic simulation of various particulate processes, such as crystallization, granulation and polymerization. This artic...The population balance modeling is regarded as a universally accepted mathematical framework for dynamic simulation of various particulate processes, such as crystallization, granulation and polymerization. This article is concerned with the application of the method of characteristics (MOC) for solving population balance models describing batch crystallization process. The growth and nucleation are considered as dominant phenomena, while the breakage and aggregation are neglected. The numerical solutions of such PBEs require high order accuracy due to the occurrence of steep moving fronts and narrow peaks in the solutions. The MOC has been found to be a very effective technique for resolving sharp discontinuities. Different case studies are carried out to analyze the accuracy of proposed algorithm. For validation, the results of MOC are compared with the available analytical solutions and the results of finite volume schemes. The results of MOC were found to be in good agreement with analytical solutions and superior than those obtained by finite volume schemes.展开更多
High-temperature oxidation is an important property to evaluate thermal protection materials. However, since oxidation is a complex process involving microstructure evolution, its quantitative analysis has always been...High-temperature oxidation is an important property to evaluate thermal protection materials. However, since oxidation is a complex process involving microstructure evolution, its quantitative analysis has always been a challenge. In this work, a phase field method （PFM） based on the thermodynamics theory is developed to simulate the oxidation behavior and oxidation induced growth stress. It involves microstructure evolution and solves the problem of quantitatively computational analysis for the oxidation behavior and growth stress. Employing this method, the diffusion process, oxidation performance, and stress evolution axe predicted for Fe-Cr-A1-Y alloys. The numerical results agree well with the experimental data. The linear relationship between the maximum growth stress and the environment oxygen concentration is found. PFM provides a powerful tool to investigate high-temperature oxidation in complex environments.展开更多
Different morphologies of zinc oxide（ZnO）,including microrods,hexagonal pyramid-like rods and flower-like rod aggregates,had been synthesized,respectively,on glass substrates by controlling the reaction conditions（...Different morphologies of zinc oxide（ZnO）,including microrods,hexagonal pyramid-like rods and flower-like rod aggregates,had been synthesized,respectively,on glass substrates by controlling the reaction conditions（such as precursor concentration,reaction time and pH value） of hydrothermal method.The morphologies of the as-obtained ZnO were observed with scanning electron microscopy and transmission electron microscopy.Also,the crystalline natures of different ZnO crystals were analyzed with X-ray diffraction.The possible growth mechanism of ZnO crystals with different morphologies was discussed.展开更多
There is substantial individual variation in the growth rates of sea cucumber Apostiehopus japonicus individuals. This necessitates additional work to grade the seed stock and lengthens the production period. We evalu...There is substantial individual variation in the growth rates of sea cucumber Apostiehopus japonicus individuals. This necessitates additional work to grade the seed stock and lengthens the production period. We evaluated the influence of three culture methods （free-mixed, isolated-mixed, isolated-alone） on individual variation in growth and assessed the relationship between feeding, energy conversion efficiency, and individual growth variation in individually cultured sea cucumbers. Of the different culture methods, animals grew best when reared in the isolated-mixed treatment （i.e., size classes were held separately）, though there was no difference in individual variation in growth between rearing treatment groups. The individual variation in growth was primarily attributed to genetic factors. The difference in food conversion efficiency caused by genetic differences among individuals was thought to be the origin of the variance. The level of individual growth variation may be altered by interactions among individuals and environmental heterogeneity. Our results suggest that, in addition to traditional seed grading, design of a new kind of substrate that changes the spatial distribution of sea cucumbers would effectively enhance growth and reduce individual variation in growth of sea cucumbers in culture.展开更多
High-quality superconducting Ca_(1-x)Na_(x)Fe_(2)As_(2)single crystals have been successfully grown by the NaAs-flux method,with sodium doping level x=0.4–0.64.The typical sizes of these crystals are more than 10 mm ...High-quality superconducting Ca_(1-x)Na_(x)Fe_(2)As_(2)single crystals have been successfully grown by the NaAs-flux method,with sodium doping level x=0.4–0.64.The typical sizes of these crystals are more than 10 mm in ab-plane and~0.1 mm along c-axis in thickness.X-ray diffraction,resistance and magnetization measurements are carried out to characterize the quality of these crystals.While no signature of magnetic phase transitions is detected in the normal state,bulk superconductivity is found for these samples,with a sharp transition at T_(c) ranging from 19.8 K(x=0.4)to 34.8 K(x=0.64).The doping dependences of the c-axis parameter and T_(c) are consistent with previous reports,suggesting a possible connection between the lattice parameters and superconductivity.展开更多
The cohesive solids in liquid flows are featured by the dynamic growth and breakage of agglomerates, and the difficulties in the development, design and optimization of these systems are related to this significant fe...The cohesive solids in liquid flows are featured by the dynamic growth and breakage of agglomerates, and the difficulties in the development, design and optimization of these systems are related to this significant feature.In this paper, discrete particle method is used to simulate a solid–liquid flow system including millions of cohesive particles, the growth rate and breakage rate of agglomerates are then systematically investigated. It was found that the most probable size of the agglomerates is determined by the balance of growth and breakage of the agglomerates the cross point of the lines of growth rate and breakage rate as a function of the particle numbers in an agglomerate, marks the most stable agglomerate size. The finding here provides a feasible way to quantify the dynamic behaviors of growth and breakage of agglomerates, and therefore offers the possibility of quantifying the effects of agglomerates on the hydrodynamics of fluid flows with cohesive particles.展开更多
文摘In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hydraulic fractures in layered porous reservoirs with modulus contrast.The coupled hydromechanical model is first verified against an analytical solution and a laboratory experiment.Then,the fracture geometry(e.g.height,aperture,and area)and fluid pressure evolutions of multiple hydraulic fractures placed in a porous reservoir interbedded with alternating stiff and soft layers are investigated using the model.The stress and pore pressure distributions within the layered reservoir during fluid injection are also presented.The simulation results reveal that stress umbrellas are easily to form among multiple hydraulic fractures’tips when propagating in soft layers,which impedes the simultaneous height growth.It is also observed that the impediment effect of soft layer is much more significant in the fractures suppressed by the preferential growth of adjoining fractures.After that,the combined effect of in situ stress ratio and fracturing spacing on the multi-fracture height growth is presented,and the results elucidate the influence of in situ stress ratio on the height growth behavior depending on the fracture spacing.Finally,it is found that the inclusion of soft layers changes the aperture distribution of outmost and interior hydraulic fractures.The results obtained from this study may provide some insights on the understanding of hydraulic fracture height containment observed in filed.
文摘It was tried to prepare the microcapsules containing grape polyphenol with the spray drying method followed by the layer-by-layer method. As grape polyphenol was water soluble, the spray drying method was adopted to obtain the higher content. As the shell material of the first microcapsules prepared by the spray drying method, palmitic acid with the melting point of 60°C was adopted in order to prevent grape polyphenol from dissolution into water. As the shell material of the second microcapsules prepared by the layer-by-layer method, chitosan was used to coat the first microcapsules and to give the microcapsules alcohol resistance. In the experiment, the spray drying conditions such as the inlet temperature and the spraying pressure, the oil soluble surfactant species and the chitosan concentration were changed. The mean diameters of microcapsules could be controlled in the range from 5 μm to 35 μm by changing the spraying pressure and the inlet temperature. The yield of microcapsules and the microencapsulation efficiency over 50% could be obtained under the conditions of P = 1.0 kgf/cm2 and Tin = 100°C. Furthermore, the microencapsulation efficiency could be increased by adding the oil soluble surfactant with the larger HLB value. Coating with chitosan could considerably increase alcohol resistance.
基金Project supported by the National Key R&D Program of China(2022YFB3204000)National Natural Science Foundation of China(51832009)。
文摘As a promising optical and piezoelectric crystal,efficient growth of LGN single crystal is crucial for its practical applications.Herein,a langanite(La_(3)Ga_(5.5)Nb_(0.5)O_(14),LGN)crystal with high quality was successfully grown by the Bridgman method along the Z direction.In order to prepare high-purity polycrystalline precursors for LGN crystal growth,the sintering conditions of LGN polycrystalline precursors were studied in detail.The melting point of LGN was also measured to provide a reference for the crystal growth temperature.For the[001]oriented wafer,the full width at half maximum(EWHM)value of the nigh-resolution X-ray diffraction(HRXRD)analysis is 38.52",demonstrating that the LGN crystal exhibits excellent crystalline quality.In addition,we also measured the thermal properties and transmission spectrum of the as-grown LGN crystal.It is found that the absorption peak at 1.85μm of the LGN crystal grown in air using the Bridgman method disappears compared with previous reports(grown in N_(2+)(1-3)vol%O_(2)atmosphere),which is attributed to the oxygen-enriched growth environment.Similar phenomenon also occurs in other LGS-type disordered crystals.It is believed that these findings may expand the potential applications of LGS series crystals at 1.85μm.
基金Supported by National Natural Science Foundation of China(Grant Nos.11671403 and 11671236)Henan Provincial General Natural Science Foundation Project(Grant No.232300420113)。
文摘In this paper,we study high energy normalized solutions for the following Schr?dinger equation{-Δu+V(x)u+λu=f(u),in R^(2),∫_(R^(2))|u|^(2)dx=c,where c>0,λ∈R will appear as a Lagrange multiplier,V(x)=ω|x|2 represents a trapping potential,and f has an exponential critical growth.Under the appropriate assumptions of f,we have obtained the existence of normalized solutions to the above Schr?dinger equation by introducing a variational method.And these solutions are also high energy solutions with positive energy.
基金supported by National Natural Science Foundation of China(No.12171152)。
文摘By using the Ljusternik-Schnirelmann category and variational method,we s-tudy the existence,multiplicity and concentration of solutions to the fractional Schrodinger equation with potentials competition as follows,ε^(N)(-△)^(s)N/sμ+V(x)|μ|^(N/s-2μ)=Q(x)h(μ)in R^(N),where ε>0 is a parameter,s ∈(0,1),2≤p<+oo and N=ps.The nonlinear term h is a diferentiable function with exponential critical growth,the absorption potential V and the reaction potential Q are continuous functions.
基金Projects(51161011,11364024)supported by the National Natural Science Foundation of ChinaProject(1204GKCA065)supported by the Key Technology R&D Program of Gansu Province,China+1 种基金Project(201210)supported by the Fundamental Research Funds for the Universities of Gansu Province,ChinaProject(J201304)supported by the Funds for Distinguished Young Scientists of Lanzhou University of Technology,China
文摘A mathematical model combined projection algorithm with phase-field method was applied. The adaptive finite element method was adopted to solve the model based on the non-uniform grid, and the behavior of dendritic growth was simulated from undercooled nickel melt under the forced flow. The simulation results show that the asymmetry behavior of the dendritic growth is caused by the forced flow. When the flow velocity is less than the critical value, the asymmetry of dendrite is little influenced by the forced flow. Once the flow velocity reaches or exceeds the critical value, the controlling factor of dendrite growth gradually changes from thermal diffusion to convection. With the increase of the flow velocity, the deflection angle towards upstream direction of the primary dendrite stem becomes larger. The effect of the dendrite growth on the flow field of the melt is apparent. With the increase of the dendrite size, the vortex is present in the downstream regions, and the vortex region is gradually enlarged. Dendrite tips appear to remelt. In addition, the adaptive finite element method can reduce CPU running time by one order of magnitude compared with uniform grid method, and the speed-up ratio is proportional to the size of computational domain.
基金Supported by the Earmarked Fund for China Agriculture Research System(CARS-12)~~
文摘The research explored effects of cultivation methods on growth, yield and quality of cassava. The results showed that the mulching treatment by direct seed- ing, the mulching treatment by transplanting, and the exposed treatment by trans- planting performed excellently in bringing seedling stage forward, improving germina- tion rate, yield and quality. For example, seedling emergence stages were 36, 31 and 31 d earlier; germination rates improved by 19.24%, 14.29% and 14.29%; yields grew by 41.98%, 26.72% and 11.45%; starch contents increased by 3.50%, 2.10% and 1.40%, respectively. Therefore, cassava in the mulching treatment by direct seeding is characterized by earlier seedling emergence stage, high germination rate, high yield and quality.
文摘In order to find the test cube for industrial robots as specified by ISO 9283, a seed cube is grown up in an irregular working space of the robot, provided that the corners of the cube do not exceed the boundary of the working space. All possible cubes are searched, and the cube with the maximum volume is selected. The calculation examples show that the method of growth can be used for a variety of industrial robots. The method of growth can determine the test cube and test points of irregular working space according to ISO 9283, and can avoid blindness and randomness in the selection of test points.
基金Projects(11375112,51472155,11275122)supported by the National Natural Science Foundation of China
文摘The growth interfaces of CdMnTe（CMT） crystals grown by traveling heater method（THM） were studied. Two types of polycrystalline CMT feed ingots synthesized in a traditional rocking furnace and vertical Bridgman（VB） furnace were adopted in THM growth, and the effects of the polycrystalline feed on the growth interface were revealed. The morphology of the growth interface of CMT crystal（CMT2） grown from the feed by vertical Bridgman was smoother with lower curvature compared with that of CMT crystal（CMT1） from the feed by rocking furnace. The radial Mn composition and Te inclusion distribution of the CMT wafers were analyzed and correlated to the growth interface. The Mn segregation along the radial direction and Te inclusion density of CMT2 were lower than those of CMT1. The VB method synthesized polycrystalline feed could improve the growth interface morphology, which is beneficial for decreasing the Te inclusions and Mn segregation in CMT wafers.
基金supported by the State Grid Technology Project(No. DG71-17-010)the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions (CIT&TCD 201504019)
文摘Lithium secondary batteries（LSBs） with high energy densities need to be further developed for future applications in portable electronic devices, electric vehicles, hybrid electric vehicles and smart grids. Lithium metal is the most promising electrode for next-generation rechargeable batteries. However, the formation of lithium dendrite on the anode surface leads to serious safety concerns and low coulombic efficiency.Recently, researchers have made great efforts and significant progresses to solve these problems. Here we review the growth mechanism and suppression method of lithium dendrite for LSBs’ anode protection. We also establish the relationship between the growth mechanism and suppression method. The research direction for building better LSBs is given by comparing the advantages and disadvantages of these methods based on the growth mechanism.
基金supported by National Natural Science Foundation of China(Grants No.50875174,51175347)Innovation Program of Shanghai Municipal Education Commission(Grant No.13ZZ114)Capacity Building Project of Local University of Shanghai Municipal Science and Technology Commission(Grant No.13160502500)
文摘The application of the adaptive growth method is limited because several key techniques during the design process need manual intervention of designers. Key techniques of the method including the ground structure construction and seed selection are studied, so as to make it possible to improve the effectiveness and applicability of the adaptive growth method in stiffener layout design optimization of plates and shells. Three schemes of ground structures, which are comprised by different shell elements and beam elements, are proposed. It is found that the main stiffener layouts resulted from different ground structures are almost the same, but the ground structure comprised by 8-nodes shell elements and both 3-nodes and 2-nodes beam elements can result in clearest stiffener layout, and has good adaptability and low computational cost. An automatic seed selection approach is proposed, which is based on such selection rules that the seeds should be positioned on where the structural strain energy is great for the minimum compliance problem, and satisfy the dispersancy requirement. The adaptive growth method with the suggested key techniques is integrated into an ANSYS-based program, which provides a design tool for the stiffener layout design optimization of plates and shells. Typical design examples, including plate and shell structures to achieve minimum compliance and maximum bulking stability are illustrated. In addition, as a practical mechanical structural design example, the stiffener layout of an inlet structure for a large-scale electrostatic precipitator is also demonstrated. The design results show that the adaptive growth method integrated with the suggested key techniques can effectively and flexibly deal with stiffener layout design problem for plates and shells with complex geometrical shape and loading conditions to achieve various design objectives, thus it provides a new solution method for engineering structural topology design optimization.
基金financially supported by the Ministry of Trade,Industry,and Energy(MOTIE),Korea,under the“Digital manufacturing platform(Digi Ma P)”(reference number N0002598)supervised by the Korea Institute for Advancement of Technology(KIAT)supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(2019R1A2C4070160)。
文摘To predict the dendrite morphology and microstructure evolution in the solidification of molten metal,numerically,lattice Boltzmann method(LBM)-cellular automata(CA)model has been developed by integrating the LBM to solve the mass transport by diffusion and convection during solidification and the CA to determine the phase transformation with respect to the solid fraction based on the local equilibrium theory.It is successfully validated with analytic solutions such as Lipton-Glicksman-Kurz(LGK)model in static melt,and Oseen-Ivantsov solution under the fluid flow conditions in terms of tip radius and velocity of the dendrite growth.The proposed LBM-CA model does not only describe different types of dendrite formations with respect to various solidification conditions such as temperature gradient and growth rate,but also predict the primary dendrite arm spacing(PDAS)and the secondary dendrite arm spacing(SDAS),quantitatively,in directional solidification(DS)experiment with Ni-based superalloy.
文摘The population balance modeling is regarded as a universally accepted mathematical framework for dynamic simulation of various particulate processes, such as crystallization, granulation and polymerization. This article is concerned with the application of the method of characteristics (MOC) for solving population balance models describing batch crystallization process. The growth and nucleation are considered as dominant phenomena, while the breakage and aggregation are neglected. The numerical solutions of such PBEs require high order accuracy due to the occurrence of steep moving fronts and narrow peaks in the solutions. The MOC has been found to be a very effective technique for resolving sharp discontinuities. Different case studies are carried out to analyze the accuracy of proposed algorithm. For validation, the results of MOC are compared with the available analytical solutions and the results of finite volume schemes. The results of MOC were found to be in good agreement with analytical solutions and superior than those obtained by finite volume schemes.
基金Project supported by the National Natural Science Foundation of China (Nos. 90505015 and10702035)
文摘High-temperature oxidation is an important property to evaluate thermal protection materials. However, since oxidation is a complex process involving microstructure evolution, its quantitative analysis has always been a challenge. In this work, a phase field method （PFM） based on the thermodynamics theory is developed to simulate the oxidation behavior and oxidation induced growth stress. It involves microstructure evolution and solves the problem of quantitatively computational analysis for the oxidation behavior and growth stress. Employing this method, the diffusion process, oxidation performance, and stress evolution axe predicted for Fe-Cr-A1-Y alloys. The numerical results agree well with the experimental data. The linear relationship between the maximum growth stress and the environment oxygen concentration is found. PFM provides a powerful tool to investigate high-temperature oxidation in complex environments.
基金supported by the Open Fund(PLN0805) of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University (SWPU),China
文摘Different morphologies of zinc oxide（ZnO）,including microrods,hexagonal pyramid-like rods and flower-like rod aggregates,had been synthesized,respectively,on glass substrates by controlling the reaction conditions（such as precursor concentration,reaction time and pH value） of hydrothermal method.The morphologies of the as-obtained ZnO were observed with scanning electron microscopy and transmission electron microscopy.Also,the crystalline natures of different ZnO crystals were analyzed with X-ray diffraction.The possible growth mechanism of ZnO crystals with different morphologies was discussed.
基金Supported by the National Natural Science Foundation of China(No.41106134)the National Marine Public Welfare Research Project of China(No.201305043)+1 种基金the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A412)the Agriculture Science Technology Achievement Transformation Fund(No.2012GB24910656)
文摘There is substantial individual variation in the growth rates of sea cucumber Apostiehopus japonicus individuals. This necessitates additional work to grade the seed stock and lengthens the production period. We evaluated the influence of three culture methods （free-mixed, isolated-mixed, isolated-alone） on individual variation in growth and assessed the relationship between feeding, energy conversion efficiency, and individual growth variation in individually cultured sea cucumbers. Of the different culture methods, animals grew best when reared in the isolated-mixed treatment （i.e., size classes were held separately）, though there was no difference in individual variation in growth between rearing treatment groups. The individual variation in growth was primarily attributed to genetic factors. The difference in food conversion efficiency caused by genetic differences among individuals was thought to be the origin of the variance. The level of individual growth variation may be altered by interactions among individuals and environmental heterogeneity. Our results suggest that, in addition to traditional seed grading, design of a new kind of substrate that changes the spatial distribution of sea cucumbers would effectively enhance growth and reduce individual variation in growth of sea cucumbers in culture.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFA0704200)the National Natural Science Foundation of China(Grant Nos.11822411 and 11961160699)+4 种基金the Strategic Priority Research Program(B)of the CAS(Grants Nos.XDB25000000 and XDB33000000)the K.C.Wong Education Foundation(Grant No.GJTD-2020-01)the Youth Innovation Promotion Association of CAS(Grant No.Y202001)the Postdoctoral Innovative Talent program(Grant No.BX2021018)the China Postdoctoral Science Foundation(Grant No.2021M700250)。
文摘High-quality superconducting Ca_(1-x)Na_(x)Fe_(2)As_(2)single crystals have been successfully grown by the NaAs-flux method,with sodium doping level x=0.4–0.64.The typical sizes of these crystals are more than 10 mm in ab-plane and~0.1 mm along c-axis in thickness.X-ray diffraction,resistance and magnetization measurements are carried out to characterize the quality of these crystals.While no signature of magnetic phase transitions is detected in the normal state,bulk superconductivity is found for these samples,with a sharp transition at T_(c) ranging from 19.8 K(x=0.4)to 34.8 K(x=0.64).The doping dependences of the c-axis parameter and T_(c) are consistent with previous reports,suggesting a possible connection between the lattice parameters and superconductivity.
基金Supported by TOTAL(DS-2885)the National Natural Science Foundation of China(91434201,21422608)the “Strategic Priority Research Program” of the Chinese Academy of Sciences(XDA07080000)
文摘The cohesive solids in liquid flows are featured by the dynamic growth and breakage of agglomerates, and the difficulties in the development, design and optimization of these systems are related to this significant feature.In this paper, discrete particle method is used to simulate a solid–liquid flow system including millions of cohesive particles, the growth rate and breakage rate of agglomerates are then systematically investigated. It was found that the most probable size of the agglomerates is determined by the balance of growth and breakage of the agglomerates the cross point of the lines of growth rate and breakage rate as a function of the particle numbers in an agglomerate, marks the most stable agglomerate size. The finding here provides a feasible way to quantify the dynamic behaviors of growth and breakage of agglomerates, and therefore offers the possibility of quantifying the effects of agglomerates on the hydrodynamics of fluid flows with cohesive particles.
