Because of the developed surface of the Triply PeriodicMinimumSurface(TPMS)structures,polylactide(PLA)products with a TPMS structure are thought to be promising bio soluble implants with the potential for targeted dru...Because of the developed surface of the Triply PeriodicMinimumSurface(TPMS)structures,polylactide(PLA)products with a TPMS structure are thought to be promising bio soluble implants with the potential for targeted drug delivery.For implants,mechanical properties are key performance characteristics,so understanding the deformation and failure mechanisms is essential for selecting the appropriate implant structure.The deformation and fracture processes in PLA samples with different interior architectures have been studied through computer simulation and experimental research.Two TPMS topologies,the Schwarz Diamond and Gyroid architectures,were used for the sample construction by 3D printing.ANSYS software was utilized to simulate compressive deformation.It was found that under the same load,the vonMises stresses in the Gyroid structure are higher than those in the Schwartz Diamond structure,which was associated with the different orientations of the cells in the studied structures in relation to the direction of the loading axis.The deformation process occurs in the local regions of the studied TPMS structures.Maximum von Mises stresses were observed in the vertical parts of the structures oriented along the load direction.It was found that,unlike the Gyroid,the Schwartz Diamond structure contains a frame that forms unique stiffening ribs,which ensures the redistribution of the load under the vertical loading direction.An analysis of the mechanical characteristics of PLA samples with the Schwartz Diamond and Gyroid structures produced by the Fused Deposition Modeling(FDM)method was correlated with computer simulation.The Schwarz Diamond-type structure was shown to have a higher absorption energy than the Gyroid one.A study of the fracture in PLA samples with various cell sizes revealed a particular feature related to the samples’periodic surface topology and the 3D printing process.Scanning electron microscopic(SEM)studies of the samples deformed by compression showed thatwith an increase in the density of the samples,the failure mechanism changes from ductile to quasi-brittle due to the complex participation of both cell deformation and fiber deformation.展开更多
A large amount of genome-wide association study(GWAS)panels together with quantitative-trait locus(QTL)information associated with breeding-targeted traits have been described in wheat(Triticum aestivum L.).However,th...A large amount of genome-wide association study(GWAS)panels together with quantitative-trait locus(QTL)information associated with breeding-targeted traits have been described in wheat(Triticum aestivum L.).However,the application of mapping results from a GWAS panel to conventional wheat breeding remains a challenge.In this study,we first report a general genetic map which was constructed from 44 published linkage maps.It permits the estimation of genetic distances between any two genetic loci with physical map positions,thereby unifying the linkage relationships between QTL,genes,and genomic markers from multiple genetic populations.Second,we describe QTL mapping in a wheat GWAS panel of 688 accessions,identifying 77 QTL associated with 12 yield and grain-quality traits.Because these QTL have known physical map positions,they could be mapped onto the general map.Finally,we present a design approach to wheat breeding by using known QTL information and computer simulation.Potential crosses between parents in the GWAS panel may be evaluated by the relative frequency of the target genotype,trait correlations in simulated progeny populations,and genetic gain of selected progenies.It is possible to simultaneously improve yield and grain quality by suitable parental selection,progeny population size,and progeny selection scheme.Applying the design approach will allow identifying the most promising crosses and selection schemes in advance of the field experiment,increasing predictability and efficiency in wheat breeding.展开更多
The new filling system is smooth filling without gas gap. It works well in avoiding the generation of defects such as porosity and inclusion. The pouring basin, sprue, runner and the gate of the bolster casting were d...The new filling system is smooth filling without gas gap. It works well in avoiding the generation of defects such as porosity and inclusion. The pouring basin, sprue, runner and the gate of the bolster casting were designed according to the principle of the new filling system. The filling and solidifciation process of the bolster casting were also simulated. It was found that the filling process was smooth, and air entrapment and shrinkage were avoided. Finally, a further validation of the new filling system of bolster casting was carried out in a foundry.展开更多
Core filling process of cast high speed steel roll was simulated.Ductile iron was used as core material.The influences of filling parameters,such as core filling time and core filling temperature,on the filling proces...Core filling process of cast high speed steel roll was simulated.Ductile iron was used as core material.The influences of filling parameters,such as core filling time and core filling temperature,on the filling process were investigated.Based on the simulated results,optimal core filling parameters were determined.The predicted temperature fields show that the temperature at the roll shoulder is the lowest during the core filling process and usually causes binding defects there.Method for solving this problem was presented.展开更多
Ca (II) speciation and effect of Gd (III) speciation on Ca (II) speciation in human blood plasma were studied by computer simulation. [CaHCO3](-) is a predominant compound species of Ca (II). Gd (III) can compete with...Ca (II) speciation and effect of Gd (III) speciation on Ca (II) speciation in human blood plasma were studied by computer simulation. [CaHCO3](-) is a predominant compound species of Ca (II). Gd (III) can compete with Ca (II) for biological molecules. The presence of Gd (III) results in a increase of concentration of free Ca (II) and a decrease of concentration of Ca (II) compounds.展开更多
Covalent organic framework (COF) is a porous material with low density and large BET (Brtmauer-Emmett-Teller) surface area. They have great potential in gas adsorption and separation. In this work, the adsorption ...Covalent organic framework (COF) is a porous material with low density and large BET (Brtmauer-Emmett-Teller) surface area. They have great potential in gas adsorption and separation. In this work, the adsorption of pure CO2 and CO2/CH4 mixture on modified COF-102 was simulated by using GCMC (grand canonical Monte Carlo). Metal Li was incorporated into COF-102 through three doping methods, including charge exchange, O^--Li6+ dipolar interaction and O^--Li^+ chemical bonding. The influence of Li doping on the adsorption of CO2 was studied. The results showed that among the three methods, the dipole doping is the best way to improve CO2 adsorption performance. Further, the ligands of COF-102 were replaced by extended aromatic moieties, such as diphenyl and pyrene. The adsorption capacity of CO2 and CH4, and the selectivity of CO2/CH4 on the ligand-replaced COF-102 were studied. The capacity of CO2 and CH4 on the ligand-replaced COF-102 had obvious changes; hence the selectivity of CO2/CH4 can be adjusted accordingly.展开更多
This article reports an experimental investigation on the axial impact buckling of thin metallic cylindrical shells fully filled with water. Low velocity impact tests are carried out by DHR-9401 drop hammer rig. The w...This article reports an experimental investigation on the axial impact buckling of thin metallic cylindrical shells fully filled with water. Low velocity impact tests are carried out by DHR-9401 drop hammer rig. The whole process of dynamic buckling is simulated using LS-DYNA computer code. The consistency between experimental observation and numerical simulation is quite satisfactory. The investigation indicates that quite high internal hydrodynamic pressure occurs inside the shell during the impact process. Under the combined action of the high internal pressure and axial compression plastic buckling occurs easily in the thin-walled shells and buckling modes take on regular and axisymmetric wrinkles.展开更多
To realize the technology of fabricating the rheologic semi-solid slurry of ZL112Y aluminum alloy via continues electromagnetic stirring process,ANSYS software was used to simulate electromagnetic force field and flui...To realize the technology of fabricating the rheologic semi-solid slurry of ZL112Y aluminum alloy via continues electromagnetic stirring process,ANSYS software was used to simulate electromagnetic force field and fluid velocity field in the alloy melt in a crucible tube in three coils.In the first section of the paper,eletromagnetic force field and fluid velocity field caused by single coil were simulated.The result of this simulation gives an average velocity of 3.2 cm/s and it is called critical velocity because a fluid velocity over it will cause a fine and spherical structure of solid primary a in a semi-solid melt.And,from this result,a reasonable temperature of semi-solid of the alloy and an electrical current intensity were established.The electrical current intensity of the result of this simulation corresponded to the current intensity used in a practice experiment,in which the primaryαwas obviously refined and sphericized.Based on this simulation of single coil electromagnetic stirring,in the second section of the paper,eletromagnetic force field and fluid velocity field caused by three coils were simulated.The result of the simulation shows that,1)there is a semi-solid zone of 32 mm from bottom of the crucible tube to the upper;2)the electrical current intensities of three coils of 400 A,600 A,and 400 A,which were set to top range,middle range and bottom range of the tube,respectively,were the optimum parameters of electromagnetic current intensity under the condition of this investigation;and 3)under effect of these electromagnetic current intensity,the fluid velocities of the melt in the tube were 6.3 cm/s in top range,3.75 cm/s in middle range,and 3.9 cm/s in bottom range of it,respectively.展开更多
AIM: To investigate the flow and mixing at the duodenal stump after gastric resection, a computer simulation was implemented. METHODS: Using the finite element method, two different Billroth fl procedure cases (A a...AIM: To investigate the flow and mixing at the duodenal stump after gastric resection, a computer simulation was implemented. METHODS: Using the finite element method, two different Billroth fl procedure cases (A and B) were modeled. Case A was defined with a shorter and almost straight duodenal section, while case B has a much longer and curved duodenal section. Velocity, pressure and food concentration distribution were determined and the numerical results were compared with experimental observations. RESULTS: The pressure distribution obtained by numerical simulation was in the range of the recorded experimental results. Case A had a more favorable pressure distribution in comparison with case B. However, case B had better performance in terms of food transport because of more continual food distribution, as well as better emptying of the duodena section. CONCLUSION: This study offers insight into the transport process within the duodenal stump section after surgical intervention, which can be useful for future patient-specific predictions of a surgical outcome.展开更多
This paper used EAM and static relaxation method to simulate the grain boundary segregation behavior of Mg in Ni-based superalloys. The results offer a better understanding in the strengthening mechanism of Mg additio...This paper used EAM and static relaxation method to simulate the grain boundary segregation behavior of Mg in Ni-based superalloys. The results offer a better understanding in the strengthening mechanism of Mg addition in superalloys. The segregation of Mg increases the grain boundary cohesive bond and the vacancy formation energy, and decreases the mobility of grain boundary dislocation. It results in the retardation of creep voids initiation and growth.展开更多
The insoluble species of Gd ( Ⅲ ) in human blood plasma were investigated by computer simulation. The distribution of the Gd(Ⅲ ) species was obtained. It was found that most of the Gd( Ⅲ ) ions were bound to phosph...The insoluble species of Gd ( Ⅲ ) in human blood plasma were investigated by computer simulation. The distribution of the Gd(Ⅲ ) species was obtained. It was found that most of the Gd( Ⅲ ) ions were bound to phosphate to form precipitate GdPO4 at the concentration of 1. 000 10-7 mol/L and when the concentration of the Gd (Ⅲ ) increased to 3. 750 X 10-4 mol/L, in excess of the concentration of phosphate, the Gd ( Ⅲ ) ions were bound to carbonate to form another kind of precipitate, Gd2(CO3)3.展开更多
The application of computer simulation technique to electronic controlled fuel injection(EFI) engine was studied to increase the development speed and improve the overall performance of the engine and car. On the basi...The application of computer simulation technique to electronic controlled fuel injection(EFI) engine was studied to increase the development speed and improve the overall performance of the engine and car. On the basis of an EFI system developed by ourselves, the simulation model of the initial control data and engine operation points during a driving cycle and the car performance pridiction model were established. This method was applied to a mini car. The experiment showed that the simulated control data has good accuracy; and the engine test points and car performances obtained by simulation are useful for the matching of EFI system with gasoline engine and the development speed is increased.展开更多
According to thermodynamics and kinetics of phase transformation,a mathematical model of phase transformation was proposed,and the microstructure evolution of an 82B rod at different cooling rates was simulated by usi...According to thermodynamics and kinetics of phase transformation,a mathematical model of phase transformation was proposed,and the microstructure evolution of an 82B rod at different cooling rates was simulated by using the FEM software Marc/Mentat,based on the measurement of time-temperature transformation(TTT)curves of the 82B rod.The simulated results were in good agreement with the actual measurements.From the results of computer simulation it was found that the cooling rate of the 82B rod,after laying,should be controlled within 5-8 ℃/s.In the microstructure of rod there were over 95% of pearlite volume fraction and a small quantity of dispersive martensite(less than 5%).展开更多
When robot is at singular configuration, the limited hand velocity wouldrequire some joints with infeasible speeds so as to lead unsafely of the system. A method of solvingthe approximate velocity of joint near singul...When robot is at singular configuration, the limited hand velocity wouldrequire some joints with infeasible speeds so as to lead unsafely of the system. A method of solvingthe approximate velocity of joint near singular configuration point by adding damped vector isproposed and a modified algorithm is provided. With the analysis of J-1 the singularconfigurations of 6R robot are divided into structure boundary singularity , boundary singularity ,inner singularity and wrist singularity. The conditions of singularities of the robot have beenascertained. The computer simulations of the singularities of the robot are developed, which havemany advantages over previous description methods of the singular configurations of robot. With thehelp of boundary singularity analysis, a application in welding trajectory planning checking of therobot has been carried out and the simulation result proved visualized and useful.展开更多
A multi-phase model of Pr(III) speciation in human interstitial fluid was constructed and insoluble Pr(III) speciation was studied. When the total concentration of Pr(III) is below 8.401E-10 mol/L, soluble Pr(III) spe...A multi-phase model of Pr(III) speciation in human interstitial fluid was constructed and insoluble Pr(III) speciation was studied. When the total concentration of Pr(III) is below 8.401E-10 mol/L, soluble Pr(III) species are main species. With rising the total concentration of Pr(III), Pr(III) is firstly bound to phosphate to form precipitate of PrPO4, then bound to carbonate and another precipitate of Pr2(CO3)3 was obtained. When the total concentration is between 1.583E-9 mol/L and 4.000E-3 mol/L, the insoluble species are predominant Pr(III) species.展开更多
The quenching process of garnett wire teeth of metallic card clothing heated by flame was researched by use of 3-D finite element method and the equation of boundary condition was established by making use of a model ...The quenching process of garnett wire teeth of metallic card clothing heated by flame was researched by use of 3-D finite element method and the equation of boundary condition was established by making use of a model of artificial neural network. The transient temperature field, phase transformation in the heating process, the quenching microstructures and the hardness distribution on quenched garnett wire teeth of metallic card clothing were simulated. The result shows that the maximum error of the hardness between the simulative value and the actual measuring value is 8.0% on only one testing point and errors are all less than 3.0% on other testing points.展开更多
A method for determination of tool-chip contact length is theoreticallypresented in orthogonal metal machining. By using computer simulation and based on the analyses ofthe elastro-plastic deformation with lagrangian ...A method for determination of tool-chip contact length is theoreticallypresented in orthogonal metal machining. By using computer simulation and based on the analyses ofthe elastro-plastic deformation with lagrangian finite element method in the deformation zone, theaccumulated representative length of the low layer, the tool-chip contact length of the chipcontacting the tool rake are calculated, experimental studies are also carried out with 0.2 percentcarbon steel. It is shown that the tool-chip contact lengths obtained from computer simulation havea good agreement with those of measured values.展开更多
A brief review of commonly encountered anions,cations and co-doped HA and Ca-deficient HA was given in the DFT studies.First,the charge compensation mechanism,the preference substitution sites and crystal structure ch...A brief review of commonly encountered anions,cations and co-doped HA and Ca-deficient HA was given in the DFT studies.First,the charge compensation mechanism,the preference substitution sites and crystal structure changes of doped HA were described and discussed.And then conclusions were drawn and future challenges were discussed.The review is expected to provide theoretical guidance for the development of bioactive HA with special structures and functions.展开更多
In this work, thermodynamical properties of a two-dimensional (21)) Lennard-Jones (L J) fluid are studied. Here, to increase the accuracy of our theoretical calculations, the correlation functions in three-partic...In this work, thermodynamical properties of a two-dimensional (21)) Lennard-Jones (L J) fluid are studied. Here, to increase the accuracy of our theoretical calculations, the correlation functions in three-particle level (triplet) are applied. To obtain the triplet correlation functions, the Attard's source particle method is extended to 21) systems. In the Attard's procedure, the inhomogeneous Ornstein Zernike (OZ) equation is solved using the Treizenberg Zwanzwig (TZ) expression and a closure relation like the hy2ernetted-chain (HNC) approximation. In the present work, we also have performed the Monte Carlo (MC) simulation. The theoretical results are in fairly agreement with the MC simulation. Also, our results show that the approach proposed here is suitable to study the 2D LJ fluid.展开更多
On the basis of transformation kinetics and thermodynamics, the austenite-ferrite transformation start temperature during deformation was predicted for several grades of low-carbon steels under different processing co...On the basis of transformation kinetics and thermodynamics, the austenite-ferrite transformation start temperature during deformation was predicted for several grades of low-carbon steels under different processing conditions. Results indicate that Ar3d temperature mostly depended on alloying composition and processing parameters. Ar3d increased as strain rate or strain increased for the same steel grade. In view of enhancement of deformation on transformation, the basic kinetics model was established to simulate deformation induced transformation behavior, using which the influence of the deformation stored energy and effective deformation ledge on the nucleation and growth can be considered. The simulated results are in good agreement with experiment results.展开更多
摘要Because of the developed surface of the Triply PeriodicMinimumSurface(TPMS)structures,polylactide(PLA)products with a TPMS structure are thought to be promising bio soluble implants with the potential for targeted drug delivery.For implants,mechanical properties are key performance characteristics,so understanding the deformation and failure mechanisms is essential for selecting the appropriate implant structure.The deformation and fracture processes in PLA samples with different interior architectures have been studied through computer simulation and experimental research.Two TPMS topologies,the Schwarz Diamond and Gyroid architectures,were used for the sample construction by 3D printing.ANSYS software was utilized to simulate compressive deformation.It was found that under the same load,the vonMises stresses in the Gyroid structure are higher than those in the Schwartz Diamond structure,which was associated with the different orientations of the cells in the studied structures in relation to the direction of the loading axis.The deformation process occurs in the local regions of the studied TPMS structures.Maximum von Mises stresses were observed in the vertical parts of the structures oriented along the load direction.It was found that,unlike the Gyroid,the Schwartz Diamond structure contains a frame that forms unique stiffening ribs,which ensures the redistribution of the load under the vertical loading direction.An analysis of the mechanical characteristics of PLA samples with the Schwartz Diamond and Gyroid structures produced by the Fused Deposition Modeling(FDM)method was correlated with computer simulation.The Schwarz Diamond-type structure was shown to have a higher absorption energy than the Gyroid one.A study of the fracture in PLA samples with various cell sizes revealed a particular feature related to the samples’periodic surface topology and the 3D printing process.Scanning electron microscopic(SEM)studies of the samples deformed by compression showed thatwith an increase in the density of the samples,the failure mechanism changes from ductile to quasi-brittle due to the complex participation of both cell deformation and fiber deformation.
基金the Hainan Yazhou Bay Seed Laboratory(B21Y10209 and B22C10212)China Postdoctoral Science Foundation(2022M713433)+1 种基金National Natural Science Foundation of China(31861143003)Innovation Program of Chinese Academy of Agricultural Sciences.
摘要A large amount of genome-wide association study(GWAS)panels together with quantitative-trait locus(QTL)information associated with breeding-targeted traits have been described in wheat(Triticum aestivum L.).However,the application of mapping results from a GWAS panel to conventional wheat breeding remains a challenge.In this study,we first report a general genetic map which was constructed from 44 published linkage maps.It permits the estimation of genetic distances between any two genetic loci with physical map positions,thereby unifying the linkage relationships between QTL,genes,and genomic markers from multiple genetic populations.Second,we describe QTL mapping in a wheat GWAS panel of 688 accessions,identifying 77 QTL associated with 12 yield and grain-quality traits.Because these QTL have known physical map positions,they could be mapped onto the general map.Finally,we present a design approach to wheat breeding by using known QTL information and computer simulation.Potential crosses between parents in the GWAS panel may be evaluated by the relative frequency of the target genotype,trait correlations in simulated progeny populations,and genetic gain of selected progenies.It is possible to simultaneously improve yield and grain quality by suitable parental selection,progeny population size,and progeny selection scheme.Applying the design approach will allow identifying the most promising crosses and selection schemes in advance of the field experiment,increasing predictability and efficiency in wheat breeding.
基金supported by the Natural Science Foundation of Liaoning Province (20092061)
摘要The new filling system is smooth filling without gas gap. It works well in avoiding the generation of defects such as porosity and inclusion. The pouring basin, sprue, runner and the gate of the bolster casting were designed according to the principle of the new filling system. The filling and solidifciation process of the bolster casting were also simulated. It was found that the filling process was smooth, and air entrapment and shrinkage were avoided. Finally, a further validation of the new filling system of bolster casting was carried out in a foundry.
摘要Core filling process of cast high speed steel roll was simulated.Ductile iron was used as core material.The influences of filling parameters,such as core filling time and core filling temperature,on the filling process were investigated.Based on the simulated results,optimal core filling parameters were determined.The predicted temperature fields show that the temperature at the roll shoulder is the lowest during the core filling process and usually causes binding defects there.Method for solving this problem was presented.
基金the NSFC for financial support of this work (Project Nos.29890280, 29971029).
摘要Ca (II) speciation and effect of Gd (III) speciation on Ca (II) speciation in human blood plasma were studied by computer simulation. [CaHCO3](-) is a predominant compound species of Ca (II). Gd (III) can compete with Ca (II) for biological molecules. The presence of Gd (III) results in a increase of concentration of free Ca (II) and a decrease of concentration of Ca (II) compounds.
基金Supported by the National Natural Science Foundation of China (20736002), the National High Technology Research and Development Program of China (2008AA062302) and Program for Changjiang Scholars and Innovative Research Team in University of China (IRT0721).
摘要Covalent organic framework (COF) is a porous material with low density and large BET (Brtmauer-Emmett-Teller) surface area. They have great potential in gas adsorption and separation. In this work, the adsorption of pure CO2 and CO2/CH4 mixture on modified COF-102 was simulated by using GCMC (grand canonical Monte Carlo). Metal Li was incorporated into COF-102 through three doping methods, including charge exchange, O^--Li6+ dipolar interaction and O^--Li^+ chemical bonding. The influence of Li doping on the adsorption of CO2 was studied. The results showed that among the three methods, the dipole doping is the best way to improve CO2 adsorption performance. Further, the ligands of COF-102 were replaced by extended aromatic moieties, such as diphenyl and pyrene. The adsorption capacity of CO2 and CH4, and the selectivity of CO2/CH4 on the ligand-replaced COF-102 were studied. The capacity of CO2 and CH4 on the ligand-replaced COF-102 had obvious changes; hence the selectivity of CO2/CH4 can be adjusted accordingly.
基金the National Natural Science Foundation of China(19672039)the Shanxi Foundation for Returned Scholars from Abroad
摘要This article reports an experimental investigation on the axial impact buckling of thin metallic cylindrical shells fully filled with water. Low velocity impact tests are carried out by DHR-9401 drop hammer rig. The whole process of dynamic buckling is simulated using LS-DYNA computer code. The consistency between experimental observation and numerical simulation is quite satisfactory. The investigation indicates that quite high internal hydrodynamic pressure occurs inside the shell during the impact process. Under the combined action of the high internal pressure and axial compression plastic buckling occurs easily in the thin-walled shells and buckling modes take on regular and axisymmetric wrinkles.
摘要To realize the technology of fabricating the rheologic semi-solid slurry of ZL112Y aluminum alloy via continues electromagnetic stirring process,ANSYS software was used to simulate electromagnetic force field and fluid velocity field in the alloy melt in a crucible tube in three coils.In the first section of the paper,eletromagnetic force field and fluid velocity field caused by single coil were simulated.The result of this simulation gives an average velocity of 3.2 cm/s and it is called critical velocity because a fluid velocity over it will cause a fine and spherical structure of solid primary a in a semi-solid melt.And,from this result,a reasonable temperature of semi-solid of the alloy and an electrical current intensity were established.The electrical current intensity of the result of this simulation corresponded to the current intensity used in a practice experiment,in which the primaryαwas obviously refined and sphericized.Based on this simulation of single coil electromagnetic stirring,in the second section of the paper,eletromagnetic force field and fluid velocity field caused by three coils were simulated.The result of the simulation shows that,1)there is a semi-solid zone of 32 mm from bottom of the crucible tube to the upper;2)the electrical current intensities of three coils of 400 A,600 A,and 400 A,which were set to top range,middle range and bottom range of the tube,respectively,were the optimum parameters of electromagnetic current intensity under the condition of this investigation;and 3)under effect of these electromagnetic current intensity,the fluid velocities of the melt in the tube were 6.3 cm/s in top range,3.75 cm/s in middle range,and 3.9 cm/s in bottom range of it,respectively.
基金Supported by The Ministry of Science of Serbia with the grants OI144028 and TR12007
摘要AIM: To investigate the flow and mixing at the duodenal stump after gastric resection, a computer simulation was implemented. METHODS: Using the finite element method, two different Billroth fl procedure cases (A and B) were modeled. Case A was defined with a shorter and almost straight duodenal section, while case B has a much longer and curved duodenal section. Velocity, pressure and food concentration distribution were determined and the numerical results were compared with experimental observations. RESULTS: The pressure distribution obtained by numerical simulation was in the range of the recorded experimental results. Case A had a more favorable pressure distribution in comparison with case B. However, case B had better performance in terms of food transport because of more continual food distribution, as well as better emptying of the duodena section. CONCLUSION: This study offers insight into the transport process within the duodenal stump section after surgical intervention, which can be useful for future patient-specific predictions of a surgical outcome.
摘要This paper used EAM and static relaxation method to simulate the grain boundary segregation behavior of Mg in Ni-based superalloys. The results offer a better understanding in the strengthening mechanism of Mg addition in superalloys. The segregation of Mg increases the grain boundary cohesive bond and the vacancy formation energy, and decreases the mobility of grain boundary dislocation. It results in the retardation of creep voids initiation and growth.
基金National Natural Science Foundation of China(Nos.29890280,29971029).
摘要The insoluble species of Gd ( Ⅲ ) in human blood plasma were investigated by computer simulation. The distribution of the Gd(Ⅲ ) species was obtained. It was found that most of the Gd( Ⅲ ) ions were bound to phosphate to form precipitate GdPO4 at the concentration of 1. 000 10-7 mol/L and when the concentration of the Gd (Ⅲ ) increased to 3. 750 X 10-4 mol/L, in excess of the concentration of phosphate, the Gd ( Ⅲ ) ions were bound to carbonate to form another kind of precipitate, Gd2(CO3)3.
摘要The application of computer simulation technique to electronic controlled fuel injection(EFI) engine was studied to increase the development speed and improve the overall performance of the engine and car. On the basis of an EFI system developed by ourselves, the simulation model of the initial control data and engine operation points during a driving cycle and the car performance pridiction model were established. This method was applied to a mini car. The experiment showed that the simulated control data has good accuracy; and the engine test points and car performances obtained by simulation are useful for the matching of EFI system with gasoline engine and the development speed is increased.
基金Item Sponsored by the National Doctorate Fund by the Ministry of Education of China(20020008011)
摘要According to thermodynamics and kinetics of phase transformation,a mathematical model of phase transformation was proposed,and the microstructure evolution of an 82B rod at different cooling rates was simulated by using the FEM software Marc/Mentat,based on the measurement of time-temperature transformation(TTT)curves of the 82B rod.The simulated results were in good agreement with the actual measurements.From the results of computer simulation it was found that the cooling rate of the 82B rod,after laying,should be controlled within 5-8 ℃/s.In the microstructure of rod there were over 95% of pearlite volume fraction and a small quantity of dispersive martensite(less than 5%).
基金This project is supported by Natonal Natural Science Foundation of China (No.50128504).
摘要When robot is at singular configuration, the limited hand velocity wouldrequire some joints with infeasible speeds so as to lead unsafely of the system. A method of solvingthe approximate velocity of joint near singular configuration point by adding damped vector isproposed and a modified algorithm is provided. With the analysis of J-1 the singularconfigurations of 6R robot are divided into structure boundary singularity , boundary singularity ,inner singularity and wrist singularity. The conditions of singularities of the robot have beenascertained. The computer simulations of the singularities of the robot are developed, which havemany advantages over previous description methods of the singular configurations of robot. With thehelp of boundary singularity analysis, a application in welding trajectory planning checking of therobot has been carried out and the simulation result proved visualized and useful.
基金We thank the NNSFC for financial support of this work (Project Nos. 29890280, 29971029).
摘要A multi-phase model of Pr(III) speciation in human interstitial fluid was constructed and insoluble Pr(III) speciation was studied. When the total concentration of Pr(III) is below 8.401E-10 mol/L, soluble Pr(III) species are main species. With rising the total concentration of Pr(III), Pr(III) is firstly bound to phosphate to form precipitate of PrPO4, then bound to carbonate and another precipitate of Pr2(CO3)3 was obtained. When the total concentration is between 1.583E-9 mol/L and 4.000E-3 mol/L, the insoluble species are predominant Pr(III) species.
摘要The quenching process of garnett wire teeth of metallic card clothing heated by flame was researched by use of 3-D finite element method and the equation of boundary condition was established by making use of a model of artificial neural network. The transient temperature field, phase transformation in the heating process, the quenching microstructures and the hardness distribution on quenched garnett wire teeth of metallic card clothing were simulated. The result shows that the maximum error of the hardness between the simulative value and the actual measuring value is 8.0% on only one testing point and errors are all less than 3.0% on other testing points.
基金This project is supported by Provincial Natural Science Foundation of Heilongjiang(No.A9809).
摘要A method for determination of tool-chip contact length is theoreticallypresented in orthogonal metal machining. By using computer simulation and based on the analyses ofthe elastro-plastic deformation with lagrangian finite element method in the deformation zone, theaccumulated representative length of the low layer, the tool-chip contact length of the chipcontacting the tool rake are calculated, experimental studies are also carried out with 0.2 percentcarbon steel. It is shown that the tool-chip contact lengths obtained from computer simulation havea good agreement with those of measured values.
基金Funded by the the National High Technology Research and Development Program("863"Program)(2015AA034202)the National Key Research and Development Program of China(2016YFB0700802)+4 种基金the Key Technology Research and Development Program of the Bureau of Science and Technology of Sichuan Province(2014GZ0174)the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the second phase)(U1501501)the Education Department Program of Sichuan province(16ZB0313)the Teaching Reform Program of Mianyang Teachers’College(Mnu-JY1512)the Innovation and Entrepreneurship Training Program of University Students in Sichuan Province(201610639077)
摘要A brief review of commonly encountered anions,cations and co-doped HA and Ca-deficient HA was given in the DFT studies.First,the charge compensation mechanism,the preference substitution sites and crystal structure changes of doped HA were described and discussed.And then conclusions were drawn and future challenges were discussed.The review is expected to provide theoretical guidance for the development of bioactive HA with special structures and functions.
摘要In this work, thermodynamical properties of a two-dimensional (21)) Lennard-Jones (L J) fluid are studied. Here, to increase the accuracy of our theoretical calculations, the correlation functions in three-particle level (triplet) are applied. To obtain the triplet correlation functions, the Attard's source particle method is extended to 21) systems. In the Attard's procedure, the inhomogeneous Ornstein Zernike (OZ) equation is solved using the Treizenberg Zwanzwig (TZ) expression and a closure relation like the hy2ernetted-chain (HNC) approximation. In the present work, we also have performed the Monte Carlo (MC) simulation. The theoretical results are in fairly agreement with the MC simulation. Also, our results show that the approach proposed here is suitable to study the 2D LJ fluid.
基金This work was financially supported by the High Technology Development Program(No.2001AA339030)the National Nat ural Science Foundation of China(No.50100404).
摘要On the basis of transformation kinetics and thermodynamics, the austenite-ferrite transformation start temperature during deformation was predicted for several grades of low-carbon steels under different processing conditions. Results indicate that Ar3d temperature mostly depended on alloying composition and processing parameters. Ar3d increased as strain rate or strain increased for the same steel grade. In view of enhancement of deformation on transformation, the basic kinetics model was established to simulate deformation induced transformation behavior, using which the influence of the deformation stored energy and effective deformation ledge on the nucleation and growth can be considered. The simulated results are in good agreement with experiment results.