Amphiphilic lipid molecules can form various micelles depending on not only their molecular composition but also their self-assembly pathway. In this work, coarse-grained molecular dynamics simulations have been appli...Amphiphilic lipid molecules can form various micelles depending on not only their molecular composition but also their self-assembly pathway. In this work, coarse-grained molecular dynamics simulations have been applied to study the micellization behaviors of mixed dipalmitoylphosphatidylcholine （DPPC）/hexadecylphosphocholine （HPC） droplets. By vary- ing DPPC/HPC composition and the size of lipid droplets, various micelles such as spherical and nonspherical （oblate or prolate） vesicles, disk-like micelles, double or single ring-like and worm-like micelles were observed. It is found that the lipid droplet as an initial state favors forming vesicles and ring-like micelles due to in situ micellization. Our simulation results demonstrate that using special initial conditions combined with various molecular compositions is an effective way to tune lipid micellar structure.展开更多
A solver is developed aiming at efficiently predicting rotor noise in hover and forward flight.In this solver,the nonlinear near-field solutions are calculated by a hybrid approach which includes the Navier–Stokes an...A solver is developed aiming at efficiently predicting rotor noise in hover and forward flight.In this solver,the nonlinear near-field solutions are calculated by a hybrid approach which includes the Navier–Stokes and Euler equations based on a moving-embedded grid system and adaptive grid methodology.A combination of the third-order upwind scheme and flux-difference splitting scheme,instead of the second-order center-difference scheme which may cause larger wake dissipation,has been employed in the present computational fluid dynamics(CFD)method.The sound pressure data in the near field can be calculated directly by solving the Navier–Stokes equations,and the sound propagation can be predicted by the Kirchhoff method.A harmonic expansion approach is presented for rotor far-field noise prediction,which gives an analytical expression for the integral function in the Kirchhoff formula.As a result,the interpolation process is simplified and the efficiency and accuracy of the interpolation are improved.Then,the high-speed impulsive(HIS)noise of a helicopter rotor at different tip Mach numbers and on different observers is calculated and analyzed in hover and forward flight,which shows a highly directional characteristic of the rotor HIS noise with a maximum value in the rotor plane,and the HSI noise weakens rapidly with the increasing of the directivity angle.In order to investigate the effects of the rotor blade-tip shape on its aeroacoustic characteristics,four kinds of blade tips are designed and their noise characteristics have been simulated.At last,a new unconventional CLOR-II blade tip has been designed,and the noise characteristics of the presented CLOR-II model rotor have been simulated and measured compared to the reference rotors with a rectangular or swept-back platform blade tip.The results demonstrate that the unconventional CLOR-II blade tip can significantly reduce the HSI noise of a rotor.展开更多
The turbine in an LH2/LOX rocket engine is designed as a two-stage supersonic partialadmission turbine. Three-dimensional steady and unsteady simulations were conducted to analyze turbine performance and aerodynamic f...The turbine in an LH2/LOX rocket engine is designed as a two-stage supersonic partialadmission turbine. Three-dimensional steady and unsteady simulations were conducted to analyze turbine performance and aerodynamic forces on rotor blades. Different configurations were employed to investigate the effects of the axial gap and nozzle distribution on the predicted performance and aerodynamic forces. Rotor blades experience unsteady aerodynamic forces because of the partial admission. Aerodynamic forces show periodicity in the admission region, and are close to zero after leaving the admission region. The unsteady forces in frequency domain indicate that components exist in a wide frequency region, and the admission passing frequency is dominant.Those multiples of the rotational frequency which are multiples of the nozzle number in a fulladmission turbine are notable components. Results show that the turbine efficiency decreases as the axial gap between nozzles and the 1 st stage rotor（rotor 1） increases. Fluctuation of the circumferential aerodynamic force on rotor 1 blades decreases with the axial gap increasing. The turbine efficiency decreases as the circumferential spacing between nozzles increases. Fluctuations of the circumferential and axial aerodynamic forces increase as the circumferential spacing increases. As for the non-equidistant nozzle distribution, it produces similar turbine performance and amplitudefrequency characteristics of forces to those of the normal configuration, when the mean spacing is equal to that of the normal case.展开更多
The present contributions deal with the development and implementation of the direct and adjoint incompressible Navie-Stokes equations in a matrix-free time-stepping context making use of the open-source OpenFOAM~ （o...The present contributions deal with the development and implementation of the direct and adjoint incompressible Navie-Stokes equations in a matrix-free time-stepping context making use of the open-source OpenFOAM~ （open source field operation and manipulation） C ＋ ＋ tool- box. It is shown that a few minor modifications in the source code can enable these multi-purpose computational fluid dynamics （CFD） solvers to carry out global instability analysis of three- dimensional flows of engineering interest, exploiting all additional capabilities of such codes. The strength of this methodology is demonstrated through the analysis of an interesting selection of ooen and wall-bounded flows.展开更多
A computational fluid dynamics （CFD） simulation method based on 3-D Navier Stokes equation and Arbitrary Lagrangian Eulerian （ALE） method is presented to analyze the grooved slip- per performance of piston pump. T...A computational fluid dynamics （CFD） simulation method based on 3-D Navier Stokes equation and Arbitrary Lagrangian Eulerian （ALE） method is presented to analyze the grooved slip- per performance of piston pump. The moving domain of grooved slipper is transformed into a fixed reference domain by the ALE method, which makes it convenient to take the effects of rotate speed, body force, temperature, and oil viscosity into account. A geometric model to express the complex structure, which covers the orifice of piston and slipper, vented groove and the oil film, is constructed. Corresponding to different oil film thicknesses calculated in light of hydrostatic equilibrium theory and boundary conditions, a set of simulations is conducted in COMSOL to analyze the pump characteristics and effects of geometry （groove width and radius, orifice size） on these characteristics. Furthermore, the mechanics and hydraulics analyses are employed to validate the CFD model, and there is an excellent agreement between simulation and analytical results. The simulation results show that the sealing land radius, orifice size and groove width all dramatically affect the slipper behavior, and an optimum tradeoff among these factors is conducive to optimizing the pump design.展开更多
The effects of the rotational speed on the fluid-induced force characteristics of a straight-through labyrinth gas seal( STLGS) are numerically investigated using the steady computational fluid dynamics( CFD) method b...The effects of the rotational speed on the fluid-induced force characteristics of a straight-through labyrinth gas seal( STLGS) are numerically investigated using the steady computational fluid dynamics( CFD) method based on a three-dimensional model of the STLGS. The fluid-induced force characteristics of the STLGS for five rotational speeds at a pressure drop of △P = 5000 Pa with and without eccentricity are computed. The grid density analysis ensures the accuracy of the present steady-CFD method. The effect and sensitivity analysis show that the changes in rotational speed affect the pressure forces,viscous forces and total pressure distributions on the rotor surface,velocity streamlines,leakage flow rates,and maximum flow velocities. The results indicate that the rotational speed inhibits the pressure forces,leakage flow rates and maximum flow velocities and promotes the viscous forces and total pressure on the rotor surface.展开更多
A fluid–structure interaction method combining a nonlinear finite element algorithm with a preconditioning finite volume method is proposed in this paper to simulate parachute transient dynamics. This method uses a t...A fluid–structure interaction method combining a nonlinear finite element algorithm with a preconditioning finite volume method is proposed in this paper to simulate parachute transient dynamics. This method uses a three-dimensional membrane–cable fabric model to represent a parachute system at a highly folded configuration. The large shape change during parachute inflation is computed by the nonlinear Newton–Raphson iteration and the linear system equation is solved by the generalized minimal residual（GMRES） method. A membrane wrinkling algorithm is also utilized to evaluate the special uniaxial tension state of membrane elements on the parachute canopy. In order to avoid large time expenses during structural nonlinear iteration, the implicit Hilber–Hughes–Taylor（HHT） time integration method is employed. For the fluid dynamic simulations, the Roe and HLLC（Harten–Lax–van Leer contact） scheme has been modified and extended to compute flow problems at all speeds. The lower–upper symmetric Gauss–Seidel（LUSGS） approximate factorization is applied to accelerate the numerical convergence speed. Finally,the test model of a highly folded C-9 parachute is simulated at a prescribed speed and the results show similar characteristics compared with experimental results and previous literature.展开更多
Small and micro unmanned aircraft are the focus of scientific interest due to their wide range of applications.They often operate in a highly unstable flight environment where the application of new morphing wing tech...Small and micro unmanned aircraft are the focus of scientific interest due to their wide range of applications.They often operate in a highly unstable flight environment where the application of new morphing wing technologies offers the opportunity to improve flight characteristics.The investigated concept comprises port and starboard adjustable wings,and an adaptive elastoflexible membrane serves as the lifting surface.The focus is on the benefits of the deforming membrane during the impact of a one-minus-cosine type gust.At a low Reynolds number of Re=264000,the morphing wing model is investigated numerically by unsteady fluid-structure interaction simulations.First,the numerical results are validated by experimental data from force and moment,flow field,and deformation measurements.Second,with the rigid wing as the baseline,the flexible case is investigated,focusing on the advantages of the elastic membrane.For all configurations studied,the maximum amplitude of the lift coefficient under gust load shows good agreement between the experimental and numerical results.During the decay of the gust,they differ more the higher the aspect ratio of the wing.When considering the flow field,the main differences are due to the separation behavior on the upper side of the wing.The flow reattaches earlier in the experiments than in the simulations,which explains the higher lift values observed in the former.Only at one intermediate configuration does the lift amplitude of the rigid configuration exceeds that of the flexible by about 12%,with the elastic membrane resulting in a smaller and more uniform peak load,which is also evident in the wing loading and hence in the root bending moment.展开更多
The flow field in junction is complicated due to the ripple property of oil flow velocity and different frequencies of two pumps in aircraft. In this study, the flow fields of T-junction and Y-junction were analyzed u...The flow field in junction is complicated due to the ripple property of oil flow velocity and different frequencies of two pumps in aircraft. In this study, the flow fields of T-junction and Y-junction were analyzed using shear stress transport （SST） model in ANSYS/CFX software. The simulation results identified the variation rule of velocity peak in T-junction with different frequencies and phase-differences, meanwhile, the eddy and velocity shock existed in the corner of the T-junction, and the limit working state was obtained. Although the eddy disappeared in Y-junction, the velocity shock and pressure loss were still too big. To address these faults, an arc-junction was designed. Based on the flow fields of arc-junction, the eddy in the junction corner disappeared and the maximum of velocity peak declined compared to T-and Y-junction. Additionally, 8 series of arc-junction with different radiuses were tested to get the variation rule of velocity peak. Through the computation of the pressure loss of three junctions, the arc-junction had a lowest loss value, and its pressure loss reached the minimum value when the curvature radius is 35.42 mm, meanwhile, the velocity shock has decreased in a low phase.展开更多
Caragana korshinskii Kom, which is a kind of excellent shrubs, has strong resistance to windstorms, and it is also a kind of forage that is of high nutritional value as well as a forming fuel conversion resource that ...Caragana korshinskii Kom, which is a kind of excellent shrubs, has strong resistance to windstorms, and it is also a kind of forage that is of high nutritional value as well as a forming fuel conversion resource that is of high caloric. Caragana korshinskii Kom is of high lignifications after growing for a few years and the toughness of it is considerably high. Currently in China, equipments of harvesting and processing for ripe crops can hardly finish the mechanized production for Caragana korshinskii Kom. Friction characteristics of woody material for Caragana korshinskii Kom under different conditions should be given when the relevant operation machinery is designed, which can provide physical parameters for transportation of Caragana korshinskii Kom as well as the designing of relevant machinery. The paper bases on the research of friction characteristics between Caragana korshinskii Kom whose diameter of 7, 10, and 13 mm under sampling directions of 0°, 45°,and 90° and machinery materials that are commonly used such as steel plate, rubber sheet and so on, and meanwhile the test considers factors such as different conditions of Caragana korshinskii Kom, different materials of machines, different angles and so on. The data strongly suggests that the average static, dynamic friction coefficient between Caragana korshinskii Kom and steel plate is 0.399 711 and0.353 022, respectively; The average static and dynamic friction coefficient between Caragana korshinskii Kom and rubber sheet is 0.965 178 and 0.883 667, respectively. The maximum of static and dynamic friction coefficients is when the angle between the direction of sampling and the direction of movement is vertical. As the angle increased, the dynamic and static friction coefficient decreased. The friction coefficient between Caragana korshinskii Kom and steel plate were increased with the increase of the diameter of Caragana korshinskii Kom, but the diameter have no effect on the dynamic friction coefficient between Caragana korshinskii Kom and rubber plate. The conclusion of this paper can provide references for research on machines that are relevant to transportation and particle forming of Caragana korshinskii Kom.展开更多
To reveal the potential fungicidal mechanism of 5-((4-((4-chlorophenoxy)methyl)-5-iodo-1H-1,2,3-triazole-1-yl)methyl)-2-methylpyrimidin-4-amine(PA-1)against Botrytis cinerea(B.cinerea),the three-dimensional structure ...To reveal the potential fungicidal mechanism of 5-((4-((4-chlorophenoxy)methyl)-5-iodo-1H-1,2,3-triazole-1-yl)methyl)-2-methylpyrimidin-4-amine(PA-1)against Botrytis cinerea(B.cinerea),the three-dimensional structure of B.cinerea pyruvate dehydrogenase complex E1 component(PDHc-E1)is homology modeled,as the PA-1 shows potent E.coli PDHc-E1 and B.cinerea inhibition.Subsequent molecular docking indicates the PA-1 can tightly bind to B.cinerea PDHc-E1.Molecular dynamic simulation and MM-PBSA calculation both demonstrate that two in-termolecular interactions,π-πstacking and hydrophobic forces,provide the most contributions to the binding of PA-1 and B.cinerea PDHc-E1.Furthermore,the halogen bonding interaction between the iodine atom in PA-1 and OH in Ser181 is also crucial.The present study provides a valuable attempt to homology model the structure of B.cinerea PDHc-E1 and some key factors for the rational structure optimization of PA-1.展开更多
基金This work was supported by the National Natural Science Foundation of China （No.20974078 and No.91127046）, Computation was carried out in High Performance Computing Center of Tianjin University.
文摘Amphiphilic lipid molecules can form various micelles depending on not only their molecular composition but also their self-assembly pathway. In this work, coarse-grained molecular dynamics simulations have been applied to study the micellization behaviors of mixed dipalmitoylphosphatidylcholine （DPPC）/hexadecylphosphocholine （HPC） droplets. By vary- ing DPPC/HPC composition and the size of lipid droplets, various micelles such as spherical and nonspherical （oblate or prolate） vesicles, disk-like micelles, double or single ring-like and worm-like micelles were observed. It is found that the lipid droplet as an initial state favors forming vesicles and ring-like micelles due to in situ micellization. Our simulation results demonstrate that using special initial conditions combined with various molecular compositions is an effective way to tune lipid micellar structure.
基金National Natural Science Foundation of China(Grant No.10872094)
文摘A solver is developed aiming at efficiently predicting rotor noise in hover and forward flight.In this solver,the nonlinear near-field solutions are calculated by a hybrid approach which includes the Navier–Stokes and Euler equations based on a moving-embedded grid system and adaptive grid methodology.A combination of the third-order upwind scheme and flux-difference splitting scheme,instead of the second-order center-difference scheme which may cause larger wake dissipation,has been employed in the present computational fluid dynamics(CFD)method.The sound pressure data in the near field can be calculated directly by solving the Navier–Stokes equations,and the sound propagation can be predicted by the Kirchhoff method.A harmonic expansion approach is presented for rotor far-field noise prediction,which gives an analytical expression for the integral function in the Kirchhoff formula.As a result,the interpolation process is simplified and the efficiency and accuracy of the interpolation are improved.Then,the high-speed impulsive(HIS)noise of a helicopter rotor at different tip Mach numbers and on different observers is calculated and analyzed in hover and forward flight,which shows a highly directional characteristic of the rotor HIS noise with a maximum value in the rotor plane,and the HSI noise weakens rapidly with the increasing of the directivity angle.In order to investigate the effects of the rotor blade-tip shape on its aeroacoustic characteristics,four kinds of blade tips are designed and their noise characteristics have been simulated.At last,a new unconventional CLOR-II blade tip has been designed,and the noise characteristics of the presented CLOR-II model rotor have been simulated and measured compared to the reference rotors with a rectangular or swept-back platform blade tip.The results demonstrate that the unconventional CLOR-II blade tip can significantly reduce the HSI noise of a rotor.
文摘The turbine in an LH2/LOX rocket engine is designed as a two-stage supersonic partialadmission turbine. Three-dimensional steady and unsteady simulations were conducted to analyze turbine performance and aerodynamic forces on rotor blades. Different configurations were employed to investigate the effects of the axial gap and nozzle distribution on the predicted performance and aerodynamic forces. Rotor blades experience unsteady aerodynamic forces because of the partial admission. Aerodynamic forces show periodicity in the admission region, and are close to zero after leaving the admission region. The unsteady forces in frequency domain indicate that components exist in a wide frequency region, and the admission passing frequency is dominant.Those multiples of the rotational frequency which are multiples of the nozzle number in a fulladmission turbine are notable components. Results show that the turbine efficiency decreases as the axial gap between nozzles and the 1 st stage rotor（rotor 1） increases. Fluctuation of the circumferential aerodynamic force on rotor 1 blades decreases with the axial gap increasing. The turbine efficiency decreases as the circumferential spacing between nozzles increases. Fluctuations of the circumferential and axial aerodynamic forces increase as the circumferential spacing increases. As for the non-equidistant nozzle distribution, it produces similar turbine performance and amplitudefrequency characteristics of forces to those of the normal configuration, when the mean spacing is equal to that of the normal case.
基金Support of the Marie Curie Grant PIRSES-GA-2009-247651‘‘FP7-PEOPLE-IRSES:ICOMASEF-Instability and Control of Massively Separated Flows”
文摘The present contributions deal with the development and implementation of the direct and adjoint incompressible Navie-Stokes equations in a matrix-free time-stepping context making use of the open-source OpenFOAM~ （open source field operation and manipulation） C ＋ ＋ tool- box. It is shown that a few minor modifications in the source code can enable these multi-purpose computational fluid dynamics （CFD） solvers to carry out global instability analysis of three- dimensional flows of engineering interest, exploiting all additional capabilities of such codes. The strength of this methodology is demonstrated through the analysis of an interesting selection of ooen and wall-bounded flows.
基金the support from the National Natural Science Foundation of China(No.51205007)the Specialized Research Fund for the Doctoral Program of Chinese Higher Education(No.20131102120019)
文摘A computational fluid dynamics （CFD） simulation method based on 3-D Navier Stokes equation and Arbitrary Lagrangian Eulerian （ALE） method is presented to analyze the grooved slip- per performance of piston pump. The moving domain of grooved slipper is transformed into a fixed reference domain by the ALE method, which makes it convenient to take the effects of rotate speed, body force, temperature, and oil viscosity into account. A geometric model to express the complex structure, which covers the orifice of piston and slipper, vented groove and the oil film, is constructed. Corresponding to different oil film thicknesses calculated in light of hydrostatic equilibrium theory and boundary conditions, a set of simulations is conducted in COMSOL to analyze the pump characteristics and effects of geometry （groove width and radius, orifice size） on these characteristics. Furthermore, the mechanics and hydraulics analyses are employed to validate the CFD model, and there is an excellent agreement between simulation and analytical results. The simulation results show that the sealing land radius, orifice size and groove width all dramatically affect the slipper behavior, and an optimum tradeoff among these factors is conducive to optimizing the pump design.
基金Supported by the National Basic Research Development Program of China(No.2012CB026006)
文摘The effects of the rotational speed on the fluid-induced force characteristics of a straight-through labyrinth gas seal( STLGS) are numerically investigated using the steady computational fluid dynamics( CFD) method based on a three-dimensional model of the STLGS. The fluid-induced force characteristics of the STLGS for five rotational speeds at a pressure drop of △P = 5000 Pa with and without eccentricity are computed. The grid density analysis ensures the accuracy of the present steady-CFD method. The effect and sensitivity analysis show that the changes in rotational speed affect the pressure forces,viscous forces and total pressure distributions on the rotor surface,velocity streamlines,leakage flow rates,and maximum flow velocities. The results indicate that the rotational speed inhibits the pressure forces,leakage flow rates and maximum flow velocities and promotes the viscous forces and total pressure on the rotor surface.
文摘A fluid–structure interaction method combining a nonlinear finite element algorithm with a preconditioning finite volume method is proposed in this paper to simulate parachute transient dynamics. This method uses a three-dimensional membrane–cable fabric model to represent a parachute system at a highly folded configuration. The large shape change during parachute inflation is computed by the nonlinear Newton–Raphson iteration and the linear system equation is solved by the generalized minimal residual（GMRES） method. A membrane wrinkling algorithm is also utilized to evaluate the special uniaxial tension state of membrane elements on the parachute canopy. In order to avoid large time expenses during structural nonlinear iteration, the implicit Hilber–Hughes–Taylor（HHT） time integration method is employed. For the fluid dynamic simulations, the Roe and HLLC（Harten–Lax–van Leer contact） scheme has been modified and extended to compute flow problems at all speeds. The lower–upper symmetric Gauss–Seidel（LUSGS） approximate factorization is applied to accelerate the numerical convergence speed. Finally,the test model of a highly folded C-9 parachute is simulated at a prescribed speed and the results show similar characteristics compared with experimental results and previous literature.
基金funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)(No.BR 1511/12-1)。
文摘Small and micro unmanned aircraft are the focus of scientific interest due to their wide range of applications.They often operate in a highly unstable flight environment where the application of new morphing wing technologies offers the opportunity to improve flight characteristics.The investigated concept comprises port and starboard adjustable wings,and an adaptive elastoflexible membrane serves as the lifting surface.The focus is on the benefits of the deforming membrane during the impact of a one-minus-cosine type gust.At a low Reynolds number of Re=264000,the morphing wing model is investigated numerically by unsteady fluid-structure interaction simulations.First,the numerical results are validated by experimental data from force and moment,flow field,and deformation measurements.Second,with the rigid wing as the baseline,the flexible case is investigated,focusing on the advantages of the elastic membrane.For all configurations studied,the maximum amplitude of the lift coefficient under gust load shows good agreement between the experimental and numerical results.During the decay of the gust,they differ more the higher the aspect ratio of the wing.When considering the flow field,the main differences are due to the separation behavior on the upper side of the wing.The flow reattaches earlier in the experiments than in the simulations,which explains the higher lift values observed in the former.Only at one intermediate configuration does the lift amplitude of the rigid configuration exceeds that of the flexible by about 12%,with the elastic membrane resulting in a smaller and more uniform peak load,which is also evident in the wing loading and hence in the root bending moment.
基金supported by the National Natural Science Foundation of China(No.51175014)
文摘The flow field in junction is complicated due to the ripple property of oil flow velocity and different frequencies of two pumps in aircraft. In this study, the flow fields of T-junction and Y-junction were analyzed using shear stress transport （SST） model in ANSYS/CFX software. The simulation results identified the variation rule of velocity peak in T-junction with different frequencies and phase-differences, meanwhile, the eddy and velocity shock existed in the corner of the T-junction, and the limit working state was obtained. Although the eddy disappeared in Y-junction, the velocity shock and pressure loss were still too big. To address these faults, an arc-junction was designed. Based on the flow fields of arc-junction, the eddy in the junction corner disappeared and the maximum of velocity peak declined compared to T-and Y-junction. Additionally, 8 series of arc-junction with different radiuses were tested to get the variation rule of velocity peak. Through the computation of the pressure loss of three junctions, the arc-junction had a lowest loss value, and its pressure loss reached the minimum value when the curvature radius is 35.42 mm, meanwhile, the velocity shock has decreased in a low phase.
文摘Caragana korshinskii Kom, which is a kind of excellent shrubs, has strong resistance to windstorms, and it is also a kind of forage that is of high nutritional value as well as a forming fuel conversion resource that is of high caloric. Caragana korshinskii Kom is of high lignifications after growing for a few years and the toughness of it is considerably high. Currently in China, equipments of harvesting and processing for ripe crops can hardly finish the mechanized production for Caragana korshinskii Kom. Friction characteristics of woody material for Caragana korshinskii Kom under different conditions should be given when the relevant operation machinery is designed, which can provide physical parameters for transportation of Caragana korshinskii Kom as well as the designing of relevant machinery. The paper bases on the research of friction characteristics between Caragana korshinskii Kom whose diameter of 7, 10, and 13 mm under sampling directions of 0°, 45°,and 90° and machinery materials that are commonly used such as steel plate, rubber sheet and so on, and meanwhile the test considers factors such as different conditions of Caragana korshinskii Kom, different materials of machines, different angles and so on. The data strongly suggests that the average static, dynamic friction coefficient between Caragana korshinskii Kom and steel plate is 0.399 711 and0.353 022, respectively; The average static and dynamic friction coefficient between Caragana korshinskii Kom and rubber sheet is 0.965 178 and 0.883 667, respectively. The maximum of static and dynamic friction coefficients is when the angle between the direction of sampling and the direction of movement is vertical. As the angle increased, the dynamic and static friction coefficient decreased. The friction coefficient between Caragana korshinskii Kom and steel plate were increased with the increase of the diameter of Caragana korshinskii Kom, but the diameter have no effect on the dynamic friction coefficient between Caragana korshinskii Kom and rubber plate. The conclusion of this paper can provide references for research on machines that are relevant to transportation and particle forming of Caragana korshinskii Kom.
基金supported by the National Natural Science Foundation of China (No. 21807084)
文摘To reveal the potential fungicidal mechanism of 5-((4-((4-chlorophenoxy)methyl)-5-iodo-1H-1,2,3-triazole-1-yl)methyl)-2-methylpyrimidin-4-amine(PA-1)against Botrytis cinerea(B.cinerea),the three-dimensional structure of B.cinerea pyruvate dehydrogenase complex E1 component(PDHc-E1)is homology modeled,as the PA-1 shows potent E.coli PDHc-E1 and B.cinerea inhibition.Subsequent molecular docking indicates the PA-1 can tightly bind to B.cinerea PDHc-E1.Molecular dynamic simulation and MM-PBSA calculation both demonstrate that two in-termolecular interactions,π-πstacking and hydrophobic forces,provide the most contributions to the binding of PA-1 and B.cinerea PDHc-E1.Furthermore,the halogen bonding interaction between the iodine atom in PA-1 and OH in Ser181 is also crucial.The present study provides a valuable attempt to homology model the structure of B.cinerea PDHc-E1 and some key factors for the rational structure optimization of PA-1.
