Amyloid beta(Aβ)monomers aggregate to form fibrils and amyloid plaques,which are critical mechanisms in the pathogenesis of Alzheimer’s disease(AD).Given the important role of Aβ1-42 aggregation in plaque formation...Amyloid beta(Aβ)monomers aggregate to form fibrils and amyloid plaques,which are critical mechanisms in the pathogenesis of Alzheimer’s disease(AD).Given the important role of Aβ1-42 aggregation in plaque formation,leading to brain lesions and cognitive impairment,numerous studies have aimed to reduce Aβaggregation and slow AD progression.The diphenylalanine(FF)sequence is critical for amyloid aggregation,and magnetic fields can affect peptide alignment due to the diamagnetic anisotropy of aromatic rings.In this study,we examined the effects of a moderate-intensity rotating magnetic field(RMF)on Aβaggregation and AD pathogenesis.Results indicated that the RMF directly inhibited Aβamyloid fibril formation and reduced Aβ-induced cytotoxicity in neural cells in vitro.Using the AD mouse model APP/PS1,RMF restored motor abilities to healthy control levels and significantly alleviated cognitive impairments,including exploration and spatial and non-spatial memory abilities.Tissue examinations demonstrated that RMF reduced amyloid plaque accumulation,attenuated microglial activation,and reduced oxidative stress in the APP/PS1 mouse brain.These findings suggest that RMF holds considerable potential as a non-invasive,high-penetration physical approach for AD treatment.展开更多
The plastic flow behavior of the rotating band material is investigated in this paper. The rotating band material is processed from H96 brass alloy, which is hardened to a much higher yield strength compared to the an...The plastic flow behavior of the rotating band material is investigated in this paper. The rotating band material is processed from H96 brass alloy, which is hardened to a much higher yield strength compared to the annealed one. The dynamically uniaxial compression behavior of the material is tested using the split Hopkinson pressure bar(SHPB) with temperature and strain rate ranging from 297 to 1073 K and500 to 3000 s^(-1), respectively, and a phenomenological plastic flow stress model is developed to describe the mechanical behavior of the material. The material is found to present noticeable temperature sensitivity and weak strain-rate sensitivity. The construction of the plastic flow stress model has two steps. Firstly, three univariate stress functions, taking plastic strain, plastic strain rate and temperature as independent variable, respectively, are proposed by fixing the other two variables. Then, as the three univariate functions describe the special cases of flow stress behavior under various conditions, the principle of stress compatibility is adopted to obtain the complete flow stress function. The numerical results show that the proposed plastic flow stress model is more suitable for the rotating band material than the existing well-known models.展开更多
To realize stable rotating spray transfer in the region of high constant current is the key of realizing high deposition rate MAG welding process without helium in shielding gas and extending the welding current rang...To realize stable rotating spray transfer in the region of high constant current is the key of realizing high deposition rate MAG welding process without helium in shielding gas and extending the welding current range of traditional MAG welding process. In this paper, the magnetic control mechanism of the rotating spray transfer is stated and mathematical model is given. Theoretic basis is established, which implements high deposition rate MAG welding process with magnetic control instead of helium in shielding gas.展开更多
Short-term(up to 30 days)predictions of Earth Rotation Parameters(ERPs)such as Polar Motion(PM:PMX and PMY)play an essential role in real-time applications related to high-precision reference frame conversion.Currentl...Short-term(up to 30 days)predictions of Earth Rotation Parameters(ERPs)such as Polar Motion(PM:PMX and PMY)play an essential role in real-time applications related to high-precision reference frame conversion.Currently,least squares(LS)+auto-regressive(AR)hybrid method is one of the main techniques of PM prediction.Besides,the weighted LS+AR hybrid method performs well for PM short-term prediction.However,the corresponding covariance information of LS fitting residuals deserves further exploration in the AR model.In this study,we have derived a modified stochastic model for the LS+AR hybrid method,namely the weighted LS+weighted AR hybrid method.By using the PM data products of IERS EOP 14 C04,the numerical results indicate that for PM short-term forecasting,the proposed weighted LS+weighted AR hybrid method shows an advantage over both the LS+AR hybrid method and the weighted LS+AR hybrid method.Compared to the mean absolute errors(MAEs)of PMX/PMY sho rt-term prediction of the LS+AR hybrid method and the weighted LS+AR hybrid method,the weighted LS+weighted AR hybrid method shows average improvements of 6.61%/12.08%and 0.24%/11.65%,respectively.Besides,for the slopes of the linear regression lines fitted to the errors of each method,the growth of the prediction error of the proposed method is slower than that of the other two methods.展开更多
Droplet size distributions have been investigated with a two-probe system above a rotatingstream tray of 300 mm diameter.The measured distributions are found to follow the upper limitedlognormal distribution with thre...Droplet size distributions have been investigated with a two-probe system above a rotatingstream tray of 300 mm diameter.The measured distributions are found to follow the upper limitedlognormal distribution with three parameters dependent primarily on gas hole F-factor.A probabilitymethod is used to describe the initial state of the droplet population above the tray,and a model fordroplet motion is presented.The results computed with model agree well with experimental data.展开更多
The deformations and stresses of a rotating cylindrical hollow disk made of incompressible functionally-graded hyper-elastic material are theoretically analyzed based on the finite elasticity theory.The hyper-elastic ...The deformations and stresses of a rotating cylindrical hollow disk made of incompressible functionally-graded hyper-elastic material are theoretically analyzed based on the finite elasticity theory.The hyper-elastic material is described by a new micro-macro transition model.Specially,the material shear modulus and density are assumed to be a function with a power law form through the radial direction,while the material inhomogeneity is thus reflected on the power index m.The integral forms of the stretches and stress components are obtained.With the obtained complicated integral forms,the composite trapezoidal rule is utilized to derive the analytical solutions,and the explicit solutions for both the stretches and the stress components are numerically obtained.By comparing the results with two classic models,the superiority of the model in our work is demonstrated.Then,the distributions of the stretches and normalized stress components are discussed in detail under the effects of m.The results indicate that the material inhomogeneity and the rotating angular velocity have significant effects on the distributions of the normalized radial and hoop stress components and the stretches.We believe that by appropriately choosing the material inhomogeneity and configuration parameters,the functionally-graded material(FGM)hyper-elastic hollow cylindrical disk can be designed to meet some unique requirements in the application fields,e.g.,soft robotics,medical devices,and conventional aerospace and mechanical industries.展开更多
A mixing-precipitation model based on the modified coalescence-redispersion model was presented to describe the flow,mixing,nucleation and growth in a rotating packed bed(RPB) .The model was coupled with population ba...A mixing-precipitation model based on the modified coalescence-redispersion model was presented to describe the flow,mixing,nucleation and growth in a rotating packed bed(RPB) .The model was coupled with population balance,mass balance and crystallization kinetics.It predicted well the influence of coalescence prob-ability,which represents the mixing intensity among droplets,on the particle number density,supersaturation and mean particle size of the produced precipitates.The effects of the radial thickness of packing,liquid flow rate and rotating speed on the product particle size were also investigated.The results indicate that the needed radial length of packing is short for sparingly soluble substance precipitation(about 40-50 mm in this work) ,and the mean parti-cle size of precipitates decreases with the increase of rotating speed and liquid flow rate,respectively.The validity of this model was verified by experiment on BaSO4 precipitation in RPB.展开更多
In this paper, the generalized Oldroyd-B with fractional calculus approach is used. An exact solution in terms of Fox-H function for flow past an accelerated horizontal plate in a rotating fluid is obtained by using d...In this paper, the generalized Oldroyd-B with fractional calculus approach is used. An exact solution in terms of Fox-H function for flow past an accelerated horizontal plate in a rotating fluid is obtained by using discrete Laplace transform method. A comparison among the influence of various parameters in the Oldroyd-B model and the angular velocity of the fluid on the velocity profiles is made through numerical method in graphic form.展开更多
In order to replace the conventional distributor, a novel asynchronous rotating air distributor, which can optimize the drying ability of fluidized bed and strengthen the drying performance of oil shale particles, is ...In order to replace the conventional distributor, a novel asynchronous rotating air distributor, which can optimize the drying ability of fluidized bed and strengthen the drying performance of oil shale particles, is creatively designed in this study. The rotating speed of the asynchronous rotating air distributor with an embedded center disk and an encircling disk is regulated to achieve the different air supply conditions. The impacts of different drying conditions on the drying characteristic of Wangqing oil shale particles are studied with the help of electronic scales. The dynamics of experimental data is analyzed with 9 common drying models. The results indicate that the particles distribution in fluidized bed can be improved and the drying time can be reduced by decreasing the rotating speed of the embedded center disk and increasing the rotating speed of the encircling disk. The drying process of oil shale particles involves a rising drying rate period, a constant drying rate period and a falling drying rate period. Regulating the air distributor rotating speed reasonably will accelerate the shift of particles from the rising drying rate period to the falling drying rate period directly. The two-term model fits properly the oil shale particles drying simulation among 9 drying models at different air supply conditions. Yet the air absorbed in the particles' pores is diffused along with the moisture evaporation, and a small amount of moisture remains on the wall of fluidized bed in each experiment, thus, the values of drying simulation are less than the experimental values.展开更多
The present research focuses on the analysis of wave propagation on a rotating viscoelastic nanobeam supported on the viscoelastic foundation which is subject to thermal gradient effects.A comprehensive and accurate m...The present research focuses on the analysis of wave propagation on a rotating viscoelastic nanobeam supported on the viscoelastic foundation which is subject to thermal gradient effects.A comprehensive and accurate model of a viscoelastic nanobeam is constructed by using a novel nonclassical mechanical model.Based on the general nonlocal theory(GNT),Kelvin-Voigt model,and Timoshenko beam theory,the motion equations for the nanobeam are obtained.Through the GNT,material hardening and softening behaviors are simultaneously taken into account during wave propagation.An analytical solution is utilized to generate the results for torsional(TO),longitudinal(LA),and transverse(TA)types of wave dispersion.Moreover,the effects of nonlocal parameters,Kelvin-Voigt damping,foundation damping,Winkler-Pasternak coefficients,rotating speed,and thermal gradient are illustrated and discussed in detail.展开更多
We study the Hcisenberg moder under the influence of a rotating magnetic field. By using a time- dependent unitary transformation, the time evolution operator for the Schrodinger equation is obtained, which involves n...We study the Hcisenberg moder under the influence of a rotating magnetic field. By using a time- dependent unitary transformation, the time evolution operator for the Schrodinger equation is obtained, which involves no chronological product. The spin vectors (mean values of the spin operators) are obtained as explicit functions of time in the most general case. A series of cyclic solutions are presented. The nonadiabatic geometric phases of these cyclic solutions are caleulated, and are expressed in terms of the solid angle subtended by the closed trace of thc total spin vector, as well as in terms of those of the individual spins.展开更多
A new feature extraction method based on 2D-hidden Markov model(HMM) is proposed. Meanwhile the time index and frequency index are introduced to represent the new features. The new feature extraction strategy is tes...A new feature extraction method based on 2D-hidden Markov model(HMM) is proposed. Meanwhile the time index and frequency index are introduced to represent the new features. The new feature extraction strategy is tested by the experimental data that collected from Bently rotor experiment system. The results show that this methodology is very effective to extract the feature of vibration signals in the rotor speed-up course and can be extended to other non-stationary signal analysis fields in the future.展开更多
A growing interest has been devoted to the contra-rotating propellers (CRPs) due to their high propulsive efficiency, torque balance, low fuel consumption, low cavitations, low noise performance and low hull vibrati...A growing interest has been devoted to the contra-rotating propellers (CRPs) due to their high propulsive efficiency, torque balance, low fuel consumption, low cavitations, low noise performance and low hull vibration. Compared with the single-screw system, it is more difficult for the open water performance prediction because forward and aft propellers interact with each other and generate a more complicated flow field around the CRPs system. The current work focuses on the open water performance prediction of contra-rotating propellers by RANS and sliding mesh method considering the effect of computational time step size and turbulence model. The validation study has been performed on two sets of contra-rotating propellers developed by David W Taylor Naval Ship R & D center. Compared with the experimental data, it shows that RANS with sliding mesh method and SST k-ω turbulence model has a good precision in the open water performance prediction of contra-rotating propellers, and small time step size can improve the level of accuracy for CRPs with the same blade number of forward and aft propellers, while a relatively large time step size is a better choice for CRPs with different blade numbers.展开更多
The hybrid scenario,which has good confinement and moderate MHD instabilities,is a proposed operation scenario for international thermonuclear experimental reactor(ITER).In this work,the effect of plasma rotation on t...The hybrid scenario,which has good confinement and moderate MHD instabilities,is a proposed operation scenario for international thermonuclear experimental reactor(ITER).In this work,the effect of plasma rotation on the HL-3 hybrid scenario is analyzed with the integrated modeling framework OMFIT.The results show that toroidal rotation has no obvious effect on confinement with a high line averaged density of n_(bar)~(7)×10^(19)m^(-3).In this case,the ion temperature only changes from 4.7 keV to 4.4 keV with the rotation decreasing from 10^(5) rad/s to 10^(3) rad/s,which means that the turbulent heat transport is not dominant.While in the scenarios characterized by lower densities,such as n_(bar)~4×10^(19)m^(-3),turbulent transport becomes dominant in determining heat transport.The ion temperature rises from 3.8 keV to 6.1 keV in the core as the rotation velocity increases from 10^(3) rad/s to 10^(5) rad/s.Despite the ion temperature rising,the rotation velocity does not obviously affect electron temperature or density.Additionally,it is noteworthy that the variation in rotation velocity does not significantly affect the global confinement of plasma in scenarios with low density or with high density.展开更多
A rotating packed bed is a typical chemical process enhancement equipment that can strengthen micromixing and mass transfer.During the operation of the rotating packed bed,the nonreactants and products irregularly adh...A rotating packed bed is a typical chemical process enhancement equipment that can strengthen micromixing and mass transfer.During the operation of the rotating packed bed,the nonreactants and products irregularly adhere to the wire mesh packing in the rotor,thus resulting in an imbalance in the vibration of the rotor,which may cause serious damage to the bearing and material leakage.This study proposes a model prediction for estimating the bearing residual life of a rotating packed bed based on rotor imbalance response analysis.This method is used to determine the influence of the mass on the imbalance in the vibration of the rotor on bearing damage.The major influence on rotor vibration was found to be exerted by the imbalanced mass and its distribution radius,as revealed by the results of orthogonal experiments.Through implementing finite element analysis,the imbalance response curve for the rotating packed bed rotor was obtained,and a correlation among rotor imbalance mass,distribution radius of imbalance mass,and bearing residue life was established via data fitting.The predicted value of the bearing life can be used as the reference basis for an early safety warning of a rotating packed bed to effectively avoid accidents.展开更多
To investigate the influence of snow particle rotational motion on the accumulation of snow in the bogie region of high-speed trains,an Euler‒Lagrange numerical approach is adopted.The study examines the effects of sn...To investigate the influence of snow particle rotational motion on the accumulation of snow in the bogie region of high-speed trains,an Euler‒Lagrange numerical approach is adopted.The study examines the effects of snow particle diameter and train speed on the ensuing dynamics.It is shown that considering snow particle rotational motion causes significant deviation in the particle trajectories with respect to non-rotating particles.Such a deviation increases with larger snow particle diameters and higher train speeds.The snow accumulation on the overall surface of the bogie increases,and the amount of snow on the vibration reduction device varies greatly.In certain conditions,the amount of accumulated snow can increase by several orders of magnitudes.展开更多
In order to detecting and tracking along the weld seam with rotating arc sensor in underwater welding,the highpressure water environment rotating arc welding hardware platform is established and welding experiments us...In order to detecting and tracking along the weld seam with rotating arc sensor in underwater welding,the highpressure water environment rotating arc welding hardware platform is established and welding experiments using rotating arc sensor is done. Different radius of rotating arc sensor is used. And the corresponding welding current and voltage is obtained,which is compared with the results of rotating arc sensor short-circuit process simulation model under high-pressure water environment established in this article. The results show that under high-pressure water environment,rotating arc radius should be optimized,otherwise the short-circuit-arcing cycle will transit to a short-circuit-arcing-abruption cycle,making the welding quality poor. At last the critical radius between the short-circuit-arcing cycle and short-circuit-arcing-abruption cycle under high-pressure water environment is obtained.展开更多
The present analysis shows that the EVM can not reflect the turbulence physics in non-inertial frame. The effects of Coriolis force on turbulence is embodied naturally in the Reynolds-stress transport equation. It is ...The present analysis shows that the EVM can not reflect the turbulence physics in non-inertial frame. The effects of Coriolis force on turbulence is embodied naturally in the Reynolds-stress transport equation. It is observed that the existing second-moment closure model with appropriate near-wall treatment can adequately predict flows in rotating channel and in axially rotating pipe for moderate rotation rate.展开更多
A simulation model is presented for the creep process of the rotating disks under the radial pressure in the presence of body forces. The finite strain theory is applied. The material is described by the Norton-Bailey...A simulation model is presented for the creep process of the rotating disks under the radial pressure in the presence of body forces. The finite strain theory is applied. The material is described by the Norton-Bailey law generalized for true stresses and logarithmic strains. A mathematical model is formulated in the form of a set of four partial differential equations with respect to the radial coordinate and time. Necessary initial and boundary conditions are also given. To make the model complete, a numerical procedure is proposed. The given example shows the effectiveness of this procedure. The results show that the classical finite element method cannot be used here because both the geometry and the loading (body forces) change with the time in the creep process, and the finite elements need to be redefined at each time step.展开更多
BACKGROUND Arthroscopic rotator cuff repair is a common surgical treatment for rotator cuff injuries(RCIs).Although this procedure has certain clinical advantages,it requires rehabilitation management interventions to...BACKGROUND Arthroscopic rotator cuff repair is a common surgical treatment for rotator cuff injuries(RCIs).Although this procedure has certain clinical advantages,it requires rehabilitation management interventions to ensure therapeutic efficacy.AIM To investigate the effect of integrated traditional Chinese medicine and Western medicine(TCM-WM)under the multidisciplinary team(MDT)model on the postoperative recovery of patients undergoing arthroscopic surgery for RCIs.METHODS This study enrolled 100 patients who underwent arthroscopic rotator cuff repair for RCIs at the Seventh People’s Hospital of Shanghai University of Traditional Chinese Medicine between June 2021 and May 2024.They were divided into a control group(n=48)that received routine rehabilitation treatment and an experimental group(n=52)that received TCM-WM under the MDT model(e.g.,acupuncture,TCM traumatology and orthopedics,and rehabilitation).The results of the Constant–Murley Shoulder Score(CMS),Visual Analogue Scale(VAS),Shoulder Pain and Disability Index(SPADI),muscular strength evaluation,and shoulder range of motion(ROM)assessments were analyzed.RESULTS After treatment,the experimental group showed significantly higher CMS scores in terms of pain,functional activity,shoulder joint mobility,and muscular strength than the baseline and those of the control group.The experimental group also exhibited significantly lower VAS and SPADI scores than the baseline and those of the control group.In addition,the experimental group showed significantly enhanced muscular strength(forward flexor and external and internal rotator muscles)and shoulder ROM(forward flexion,abduction,and lateral abduction)after treatment compared with the control group.CONCLUSION TCM-WM under the MDT model improved shoulder joint function,relieved postoperative pain,promoted postoperative functional recovery,and facilitated the recovery of muscular strength and shoulder ROM in patients with RCIs who underwent arthroscopic rotator cuff repair.展开更多
基金National Key R&D Program of China(2023YFB3507004)National Natural Science Foundation of China(U21A20148)+2 种基金International Partnership Program of Chinese Academy of Sciences(116134KYSB20210052)Heye Health Technology Chong Ming Project(HYCMP2021010)CASHIPS Director’s Fund(BJPY2021A06)。
文摘Amyloid beta(Aβ)monomers aggregate to form fibrils and amyloid plaques,which are critical mechanisms in the pathogenesis of Alzheimer’s disease(AD).Given the important role of Aβ1-42 aggregation in plaque formation,leading to brain lesions and cognitive impairment,numerous studies have aimed to reduce Aβaggregation and slow AD progression.The diphenylalanine(FF)sequence is critical for amyloid aggregation,and magnetic fields can affect peptide alignment due to the diamagnetic anisotropy of aromatic rings.In this study,we examined the effects of a moderate-intensity rotating magnetic field(RMF)on Aβaggregation and AD pathogenesis.Results indicated that the RMF directly inhibited Aβamyloid fibril formation and reduced Aβ-induced cytotoxicity in neural cells in vitro.Using the AD mouse model APP/PS1,RMF restored motor abilities to healthy control levels and significantly alleviated cognitive impairments,including exploration and spatial and non-spatial memory abilities.Tissue examinations demonstrated that RMF reduced amyloid plaque accumulation,attenuated microglial activation,and reduced oxidative stress in the APP/PS1 mouse brain.These findings suggest that RMF holds considerable potential as a non-invasive,high-penetration physical approach for AD treatment.
基金the support from National Natural Science Foundation of China (Grant Nos. 11702137 and U2141246)。
文摘The plastic flow behavior of the rotating band material is investigated in this paper. The rotating band material is processed from H96 brass alloy, which is hardened to a much higher yield strength compared to the annealed one. The dynamically uniaxial compression behavior of the material is tested using the split Hopkinson pressure bar(SHPB) with temperature and strain rate ranging from 297 to 1073 K and500 to 3000 s^(-1), respectively, and a phenomenological plastic flow stress model is developed to describe the mechanical behavior of the material. The material is found to present noticeable temperature sensitivity and weak strain-rate sensitivity. The construction of the plastic flow stress model has two steps. Firstly, three univariate stress functions, taking plastic strain, plastic strain rate and temperature as independent variable, respectively, are proposed by fixing the other two variables. Then, as the three univariate functions describe the special cases of flow stress behavior under various conditions, the principle of stress compatibility is adopted to obtain the complete flow stress function. The numerical results show that the proposed plastic flow stress model is more suitable for the rotating band material than the existing well-known models.
文摘To realize stable rotating spray transfer in the region of high constant current is the key of realizing high deposition rate MAG welding process without helium in shielding gas and extending the welding current range of traditional MAG welding process. In this paper, the magnetic control mechanism of the rotating spray transfer is stated and mathematical model is given. Theoretic basis is established, which implements high deposition rate MAG welding process with magnetic control instead of helium in shielding gas.
基金supported by National Natural Science Foundation of China,China(No.42004016)HuBei Natural Science Fund,China(No.2020CFB329)+1 种基金HuNan Natural Science Fund,China(No.2023JJ60559,2023JJ60560)the State Key Laboratory of Geodesy and Earth’s Dynamics self-deployment project,China(No.S21L6101)。
文摘Short-term(up to 30 days)predictions of Earth Rotation Parameters(ERPs)such as Polar Motion(PM:PMX and PMY)play an essential role in real-time applications related to high-precision reference frame conversion.Currently,least squares(LS)+auto-regressive(AR)hybrid method is one of the main techniques of PM prediction.Besides,the weighted LS+AR hybrid method performs well for PM short-term prediction.However,the corresponding covariance information of LS fitting residuals deserves further exploration in the AR model.In this study,we have derived a modified stochastic model for the LS+AR hybrid method,namely the weighted LS+weighted AR hybrid method.By using the PM data products of IERS EOP 14 C04,the numerical results indicate that for PM short-term forecasting,the proposed weighted LS+weighted AR hybrid method shows an advantage over both the LS+AR hybrid method and the weighted LS+AR hybrid method.Compared to the mean absolute errors(MAEs)of PMX/PMY sho rt-term prediction of the LS+AR hybrid method and the weighted LS+AR hybrid method,the weighted LS+weighted AR hybrid method shows average improvements of 6.61%/12.08%and 0.24%/11.65%,respectively.Besides,for the slopes of the linear regression lines fitted to the errors of each method,the growth of the prediction error of the proposed method is slower than that of the other two methods.
基金Supported by the National and Zhejiang Provincial Natural Science Foundations.
文摘Droplet size distributions have been investigated with a two-probe system above a rotatingstream tray of 300 mm diameter.The measured distributions are found to follow the upper limitedlognormal distribution with three parameters dependent primarily on gas hole F-factor.A probabilitymethod is used to describe the initial state of the droplet population above the tray,and a model fordroplet motion is presented.The results computed with model agree well with experimental data.
基金supported by the National Natural Science Foundation of China(No.11972144)the Shanxi Province Specialized Research and Development Breakthrough in Key Core and Generic Technologies(Key Research and Development Program)(No.2020XXX017)the Fundamental Research Program of Shanxi Province of China(No.202203021211134)。
文摘The deformations and stresses of a rotating cylindrical hollow disk made of incompressible functionally-graded hyper-elastic material are theoretically analyzed based on the finite elasticity theory.The hyper-elastic material is described by a new micro-macro transition model.Specially,the material shear modulus and density are assumed to be a function with a power law form through the radial direction,while the material inhomogeneity is thus reflected on the power index m.The integral forms of the stretches and stress components are obtained.With the obtained complicated integral forms,the composite trapezoidal rule is utilized to derive the analytical solutions,and the explicit solutions for both the stretches and the stress components are numerically obtained.By comparing the results with two classic models,the superiority of the model in our work is demonstrated.Then,the distributions of the stretches and normalized stress components are discussed in detail under the effects of m.The results indicate that the material inhomogeneity and the rotating angular velocity have significant effects on the distributions of the normalized radial and hoop stress components and the stretches.We believe that by appropriately choosing the material inhomogeneity and configuration parameters,the functionally-graded material(FGM)hyper-elastic hollow cylindrical disk can be designed to meet some unique requirements in the application fields,e.g.,soft robotics,medical devices,and conventional aerospace and mechanical industries.
基金Supported by the National Natural Science Foundation of China(20821004 20325621) Beijing Municipal Commission of Education(JD100100403)
文摘A mixing-precipitation model based on the modified coalescence-redispersion model was presented to describe the flow,mixing,nucleation and growth in a rotating packed bed(RPB) .The model was coupled with population balance,mass balance and crystallization kinetics.It predicted well the influence of coalescence prob-ability,which represents the mixing intensity among droplets,on the particle number density,supersaturation and mean particle size of the produced precipitates.The effects of the radial thickness of packing,liquid flow rate and rotating speed on the product particle size were also investigated.The results indicate that the needed radial length of packing is short for sparingly soluble substance precipitation(about 40-50 mm in this work) ,and the mean parti-cle size of precipitates decreases with the increase of rotating speed and liquid flow rate,respectively.The validity of this model was verified by experiment on BaSO4 precipitation in RPB.
基金supported by The project supported by the Natural Science Foundation of Shandong Province of China (Y2007A06)
文摘In this paper, the generalized Oldroyd-B with fractional calculus approach is used. An exact solution in terms of Fox-H function for flow past an accelerated horizontal plate in a rotating fluid is obtained by using discrete Laplace transform method. A comparison among the influence of various parameters in the Oldroyd-B model and the angular velocity of the fluid on the velocity profiles is made through numerical method in graphic form.
基金supported by the National Natural Science Foundation of China(Grant No.51276033,No.51541608)
文摘In order to replace the conventional distributor, a novel asynchronous rotating air distributor, which can optimize the drying ability of fluidized bed and strengthen the drying performance of oil shale particles, is creatively designed in this study. The rotating speed of the asynchronous rotating air distributor with an embedded center disk and an encircling disk is regulated to achieve the different air supply conditions. The impacts of different drying conditions on the drying characteristic of Wangqing oil shale particles are studied with the help of electronic scales. The dynamics of experimental data is analyzed with 9 common drying models. The results indicate that the particles distribution in fluidized bed can be improved and the drying time can be reduced by decreasing the rotating speed of the embedded center disk and increasing the rotating speed of the encircling disk. The drying process of oil shale particles involves a rising drying rate period, a constant drying rate period and a falling drying rate period. Regulating the air distributor rotating speed reasonably will accelerate the shift of particles from the rising drying rate period to the falling drying rate period directly. The two-term model fits properly the oil shale particles drying simulation among 9 drying models at different air supply conditions. Yet the air absorbed in the particles' pores is diffused along with the moisture evaporation, and a small amount of moisture remains on the wall of fluidized bed in each experiment, thus, the values of drying simulation are less than the experimental values.
文摘The present research focuses on the analysis of wave propagation on a rotating viscoelastic nanobeam supported on the viscoelastic foundation which is subject to thermal gradient effects.A comprehensive and accurate model of a viscoelastic nanobeam is constructed by using a novel nonclassical mechanical model.Based on the general nonlocal theory(GNT),Kelvin-Voigt model,and Timoshenko beam theory,the motion equations for the nanobeam are obtained.Through the GNT,material hardening and softening behaviors are simultaneously taken into account during wave propagation.An analytical solution is utilized to generate the results for torsional(TO),longitudinal(LA),and transverse(TA)types of wave dispersion.Moreover,the effects of nonlocal parameters,Kelvin-Voigt damping,foundation damping,Winkler-Pasternak coefficients,rotating speed,and thermal gradient are illustrated and discussed in detail.
文摘We study the Hcisenberg moder under the influence of a rotating magnetic field. By using a time- dependent unitary transformation, the time evolution operator for the Schrodinger equation is obtained, which involves no chronological product. The spin vectors (mean values of the spin operators) are obtained as explicit functions of time in the most general case. A series of cyclic solutions are presented. The nonadiabatic geometric phases of these cyclic solutions are caleulated, and are expressed in terms of the solid angle subtended by the closed trace of thc total spin vector, as well as in terms of those of the individual spins.
基金This project is supported by National Natural Science Foundation of China(No.50075079).
文摘A new feature extraction method based on 2D-hidden Markov model(HMM) is proposed. Meanwhile the time index and frequency index are introduced to represent the new features. The new feature extraction strategy is tested by the experimental data that collected from Bently rotor experiment system. The results show that this methodology is very effective to extract the feature of vibration signals in the rotor speed-up course and can be extended to other non-stationary signal analysis fields in the future.
基金supported by the National Natural Science Foundation of China(Grant No.51079157)
文摘A growing interest has been devoted to the contra-rotating propellers (CRPs) due to their high propulsive efficiency, torque balance, low fuel consumption, low cavitations, low noise performance and low hull vibration. Compared with the single-screw system, it is more difficult for the open water performance prediction because forward and aft propellers interact with each other and generate a more complicated flow field around the CRPs system. The current work focuses on the open water performance prediction of contra-rotating propellers by RANS and sliding mesh method considering the effect of computational time step size and turbulence model. The validation study has been performed on two sets of contra-rotating propellers developed by David W Taylor Naval Ship R & D center. Compared with the experimental data, it shows that RANS with sliding mesh method and SST k-ω turbulence model has a good precision in the open water performance prediction of contra-rotating propellers, and small time step size can improve the level of accuracy for CRPs with the same blade number of forward and aft propellers, while a relatively large time step size is a better choice for CRPs with different blade numbers.
基金Project supported by the National Magnetic Confinement Fusion Program of China (Grants Nos.2019YFE03040002 and 2018YFE0301101)the Talent Project of China National Nuclear Corporation,China (Grant No.2022JZYF-01)。
文摘The hybrid scenario,which has good confinement and moderate MHD instabilities,is a proposed operation scenario for international thermonuclear experimental reactor(ITER).In this work,the effect of plasma rotation on the HL-3 hybrid scenario is analyzed with the integrated modeling framework OMFIT.The results show that toroidal rotation has no obvious effect on confinement with a high line averaged density of n_(bar)~(7)×10^(19)m^(-3).In this case,the ion temperature only changes from 4.7 keV to 4.4 keV with the rotation decreasing from 10^(5) rad/s to 10^(3) rad/s,which means that the turbulent heat transport is not dominant.While in the scenarios characterized by lower densities,such as n_(bar)~4×10^(19)m^(-3),turbulent transport becomes dominant in determining heat transport.The ion temperature rises from 3.8 keV to 6.1 keV in the core as the rotation velocity increases from 10^(3) rad/s to 10^(5) rad/s.Despite the ion temperature rising,the rotation velocity does not obviously affect electron temperature or density.Additionally,it is noteworthy that the variation in rotation velocity does not significantly affect the global confinement of plasma in scenarios with low density or with high density.
基金the High-Performance Computing Platform of Beijing University of Chemical Technology(BUCT)for supporting this papersupported by the Fundamental Research Funds for the Central Universities(JD2319)+2 种基金the CNOOC Technical Cooperation Project(ZX2022ZCTYF7612)the National Natural Science Foundation of China(51775029,52004014)the Chinese Universities Scientific Fund(XK2020-04)。
文摘A rotating packed bed is a typical chemical process enhancement equipment that can strengthen micromixing and mass transfer.During the operation of the rotating packed bed,the nonreactants and products irregularly adhere to the wire mesh packing in the rotor,thus resulting in an imbalance in the vibration of the rotor,which may cause serious damage to the bearing and material leakage.This study proposes a model prediction for estimating the bearing residual life of a rotating packed bed based on rotor imbalance response analysis.This method is used to determine the influence of the mass on the imbalance in the vibration of the rotor on bearing damage.The major influence on rotor vibration was found to be exerted by the imbalanced mass and its distribution radius,as revealed by the results of orthogonal experiments.Through implementing finite element analysis,the imbalance response curve for the rotating packed bed rotor was obtained,and a correlation among rotor imbalance mass,distribution radius of imbalance mass,and bearing residue life was established via data fitting.The predicted value of the bearing life can be used as the reference basis for an early safety warning of a rotating packed bed to effectively avoid accidents.
基金funded by The National Natural Science Foundation of China(Grant No.12172308)the Provincial Natural Science Foundation of Hunan(Grant No.2023JJ40260).
文摘To investigate the influence of snow particle rotational motion on the accumulation of snow in the bogie region of high-speed trains,an Euler‒Lagrange numerical approach is adopted.The study examines the effects of snow particle diameter and train speed on the ensuing dynamics.It is shown that considering snow particle rotational motion causes significant deviation in the particle trajectories with respect to non-rotating particles.Such a deviation increases with larger snow particle diameters and higher train speeds.The snow accumulation on the overall surface of the bogie increases,and the amount of snow on the vibration reduction device varies greatly.In certain conditions,the amount of accumulated snow can increase by several orders of magnitudes.
基金supported by the National Natural Science Foundation of China(Grant No.51665016)founded by the China Scholarship Council(Grant No.201508360113)
文摘In order to detecting and tracking along the weld seam with rotating arc sensor in underwater welding,the highpressure water environment rotating arc welding hardware platform is established and welding experiments using rotating arc sensor is done. Different radius of rotating arc sensor is used. And the corresponding welding current and voltage is obtained,which is compared with the results of rotating arc sensor short-circuit process simulation model under high-pressure water environment established in this article. The results show that under high-pressure water environment,rotating arc radius should be optimized,otherwise the short-circuit-arcing cycle will transit to a short-circuit-arcing-abruption cycle,making the welding quality poor. At last the critical radius between the short-circuit-arcing cycle and short-circuit-arcing-abruption cycle under high-pressure water environment is obtained.
基金The project supported by the National Natural Science Foundation of ChinaState Education Commission and Tsinghua University
文摘The present analysis shows that the EVM can not reflect the turbulence physics in non-inertial frame. The effects of Coriolis force on turbulence is embodied naturally in the Reynolds-stress transport equation. It is observed that the existing second-moment closure model with appropriate near-wall treatment can adequately predict flows in rotating channel and in axially rotating pipe for moderate rotation rate.
文摘A simulation model is presented for the creep process of the rotating disks under the radial pressure in the presence of body forces. The finite strain theory is applied. The material is described by the Norton-Bailey law generalized for true stresses and logarithmic strains. A mathematical model is formulated in the form of a set of four partial differential equations with respect to the radial coordinate and time. Necessary initial and boundary conditions are also given. To make the model complete, a numerical procedure is proposed. The given example shows the effectiveness of this procedure. The results show that the classical finite element method cannot be used here because both the geometry and the loading (body forces) change with the time in the creep process, and the finite elements need to be redefined at each time step.
基金General Project of Health and Family Planning Scientific Research of Pudong New Area Health Commission:Evaluation of the Clinical Effectiveness of the Integrated Traditional Chinese and Western Medicine Clinical Program for Accelerating Postoperative Recovery of Patients with Rotator cuff Injury under the Multidisciplinary Team Mode,No.PW2021A-66Shanghai Municipal Health Commission Key Department of Integrated Traditional Chinese and Western MedicinePeak Discipline of Traditional Chinese Medicine(Orthopedics and Traumatology Department of Integrated Traditional Chinese and Western Medicine),Shanghai Pudong New Area Health Commission,No.YC-2023-0601.
文摘BACKGROUND Arthroscopic rotator cuff repair is a common surgical treatment for rotator cuff injuries(RCIs).Although this procedure has certain clinical advantages,it requires rehabilitation management interventions to ensure therapeutic efficacy.AIM To investigate the effect of integrated traditional Chinese medicine and Western medicine(TCM-WM)under the multidisciplinary team(MDT)model on the postoperative recovery of patients undergoing arthroscopic surgery for RCIs.METHODS This study enrolled 100 patients who underwent arthroscopic rotator cuff repair for RCIs at the Seventh People’s Hospital of Shanghai University of Traditional Chinese Medicine between June 2021 and May 2024.They were divided into a control group(n=48)that received routine rehabilitation treatment and an experimental group(n=52)that received TCM-WM under the MDT model(e.g.,acupuncture,TCM traumatology and orthopedics,and rehabilitation).The results of the Constant–Murley Shoulder Score(CMS),Visual Analogue Scale(VAS),Shoulder Pain and Disability Index(SPADI),muscular strength evaluation,and shoulder range of motion(ROM)assessments were analyzed.RESULTS After treatment,the experimental group showed significantly higher CMS scores in terms of pain,functional activity,shoulder joint mobility,and muscular strength than the baseline and those of the control group.The experimental group also exhibited significantly lower VAS and SPADI scores than the baseline and those of the control group.In addition,the experimental group showed significantly enhanced muscular strength(forward flexor and external and internal rotator muscles)and shoulder ROM(forward flexion,abduction,and lateral abduction)after treatment compared with the control group.CONCLUSION TCM-WM under the MDT model improved shoulder joint function,relieved postoperative pain,promoted postoperative functional recovery,and facilitated the recovery of muscular strength and shoulder ROM in patients with RCIs who underwent arthroscopic rotator cuff repair.