A cantilever beam with Damping Material Applying Rubber Magnetic Powder （DRM） has been investigated. Two methods are selected to hold DRM to a vibrating steel beam, one is to attach DRM by the magnetic attractive fo...A cantilever beam with Damping Material Applying Rubber Magnetic Powder （DRM） has been investigated. Two methods are selected to hold DRM to a vibrating steel beam, one is to attach DRM by the magnetic attractive force （called DRM beam） and the other by adhesive bonding （called AB-DRM beam）. Different from the damping property of AB-DRM beam caused by shear deformation of damping material, the damping property of DRM beam is characterized by the sliding frictional loss together with the internal loss of damping material. The authors established a formulation to predict the damping characteristics of DRM beam, which was validated experimentally. It is found that rubber material loss factor β has a decisive influence on damping improvement of DRM beam versus AB-DRM beam. If β is smaller than the critical value around 0.8255, a valid range of vibratory amplitude always exists in which DRM beam can achieve better damping than AB-DRM beam; conversely, if β is bigger than the critical value, the valid range does not exist when slide occurs. Such results are used to determine the merits and limitations of DRM and develop design guidelines.展开更多
Northeast China(NEC)is one of the vital commercial grain bases in China and it has suffered from soil erosion due to prolonged cultivation and lack of protection.To determine long-term trends of precipi-tation and rai...Northeast China(NEC)is one of the vital commercial grain bases in China and it has suffered from soil erosion due to prolonged cultivation and lack of protection.To determine long-term trends of precipi-tation and rainfall erosivity over NEC during the latest decades,daily precipitation for the entire year during 1961-2020 and hourly precipitation for the warm season(May to September)during 1971-2020 were collected for 192 and 126 stations,respectively.Three seasons,including the cold season(October to April),early warm season(May to June),and late warm season(July to September)were divided according to the combination of precipitation and vegetation.Results demonstrate:(1)Daily precipita-tion reveals total precipitation and rainfall erosivity in the cold season and early warm season increase significantly at relative rates of 3.1%-6.1%compared with the average during 1961-2020,and those in the late warm season decrease insignificantly.(2)Hourly precipitation reveals storms occurring in the early and late warm seasons have undergone significant increasing changes,which shift towards longer storm duration,larger amount,peak intensity,kinetic energy,and rainfall erosivity during 1971-2020.Moreover,the frequency of extreme storms increased.(3)Rainfall erosivities estimated from daily pre-cipitation during 1971-2020 increase insignificantly for the early and late warm season,whereas those from hourly precipitation increase significantly(6.1%and 5.5%,respectively),which indicates daily precipitation may not be able to capture the trend fully under the warming background,and precipi-tation at higher resolutions than the daily scale is necessary to detect trends of rainfall erosivity more accurately.展开更多
An adaptive neuro-fuzzy inference system （ANFIS） is introduced to predict the dynamic behavior of beams. The effects of axial forces and large displacements are considered in the analysis. A database of tests for th...An adaptive neuro-fuzzy inference system （ANFIS） is introduced to predict the dynamic behavior of beams. The effects of axial forces and large displacements are considered in the analysis. A database of tests for the dynamic characteristics of beams is developed from the experimental tests. The responses of nonlinear vibration force for the single and multiple-stepped beams are calculated from the finite element method （FEM）, experimental tests and neuro-fuzzy model for comparison. The neuro-fuzzy model provides a general framework for the combination of neural networks and fuzzy logic. It is more flexible with more options of incorporating the fuzzy nature of the real-world system and is an useful estimation tool for the dynamic characteristics of beams. Therefore, ANFIS can be a useful tool for dynamic behaviour analysis of multiple-stepped beams subjected to axial loads and large displacement.展开更多
Garvey-Kelson mass relations connect nuclear masses of neighboring nuclei within high accuracy, and provide us with convenient tools in predicting unknown masses by extrapolations from existent experimental data. In t...Garvey-Kelson mass relations connect nuclear masses of neighboring nuclei within high accuracy, and provide us with convenient tools in predicting unknown masses by extrapolations from existent experimental data. In this paper we investigate optimal"channels" of the Garvey-Kelson relations in extrapolation to the unknown regions, and tabulate our predicted masses by using these optimized channels of the Garvey-Kelson relations.展开更多
Based on the continuity of the derivatives of the Non-Uniform Rational B-Splines (NURBS) curve and the Jaumann strain measure, the present paper adopted the position coordinates of the control points as the degrees of...Based on the continuity of the derivatives of the Non-Uniform Rational B-Splines (NURBS) curve and the Jaumann strain measure, the present paper adopted the position coordinates of the control points as the degrees of freedom and developed a planar rotation-free Euler-Bernoulli beam element for isogeometric analysis, where the derivatives of the field variables with respect to the arc-length were expressed as the sum of the weighted sum of the position coordinates of the control points, and the NURBS basis functions were used as the weight functions. Furthermore, the concept of bending strip was used to involve the rigid connection between multiple patches. Several typical examples with geometric nonlinearities were used to demonstrate the accuracy and effectiveness of the proposed algorithm. The presented formulation fully accounts for the geometric nonlinearities and can be used to study the snap-through and snap-back phenomena of flexible beams.展开更多
Background In the new International League Against Epilepsy(ILAE)classification of seizure types,generalized seizures such as absence seizures(ASs)may originate from a focal point and rapidly spread to the bilaterally...Background In the new International League Against Epilepsy(ILAE)classification of seizure types,generalized seizures such as absence seizures(ASs)may originate from a focal point and rapidly spread to the bilaterally distributed brain network.Increasing evidence from animal and clinical studies has indicated that focal changes may occur prior to ASs;however,the relationship of ASs with epileptogenic lesions remains unclear.Methods We retrospectively collected and analyzed the clinical,imaging,and electrophysiological data of 16 patients who had ASs and structural lesions with seizure-free outcomes after lesion resection.Results In semiology analysis,nine patients displayed focal onset;only two patients showed simple ASs,and seizure types other than ASs were observed in the remaining patients.On ictal electroencephalography(EEG),four patients showed bilateral synchronous symmetric 3 Hz generalized spike-wave discharges(GSWDs),and the remaining patients showed bilateral 1.5–2.5 Hz GSWDs.Moreover,most patients(13/16,81.3%)exhibited focal features in addition to ASs,while interictal EEG was the same in 12 patients.Furthermore,on stereoelectroencephalogram(SEEG),2/5 patients showed focal discharges before bilateral burst GSWDs.Additionally,all patients had structural lesions on imaging.In four typical AS patients,the lesions were located in deep brain regions.Notably,in 9 patients(9/16,56%),the lesions were located in the posterior cortex.All patients underwent lesion resection and had seizure-free outcomes during follow-up,and intelligence quotient(IQ)also improved by 10.71±3.90 one year after surgery.Conclusions Patients with lesion-related epilepsy may present with ASs that have a focal onset and are associated with good surgical outcomes.展开更多
基金the National Natural Science Foundation of China (No.10472035).
文摘A cantilever beam with Damping Material Applying Rubber Magnetic Powder （DRM） has been investigated. Two methods are selected to hold DRM to a vibrating steel beam, one is to attach DRM by the magnetic attractive force （called DRM beam） and the other by adhesive bonding （called AB-DRM beam）. Different from the damping property of AB-DRM beam caused by shear deformation of damping material, the damping property of DRM beam is characterized by the sliding frictional loss together with the internal loss of damping material. The authors established a formulation to predict the damping characteristics of DRM beam, which was validated experimentally. It is found that rubber material loss factor β has a decisive influence on damping improvement of DRM beam versus AB-DRM beam. If β is smaller than the critical value around 0.8255, a valid range of vibratory amplitude always exists in which DRM beam can achieve better damping than AB-DRM beam; conversely, if β is bigger than the critical value, the valid range does not exist when slide occurs. Such results are used to determine the merits and limitations of DRM and develop design guidelines.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2021YFE0113800)the National Key Research and Development Program of China(Grant No.2021YFD1500705)the Project for Recruited Talents to Start Up Their Work and Research in Beijing Normal University at Zhuhai(310432116).
文摘Northeast China(NEC)is one of the vital commercial grain bases in China and it has suffered from soil erosion due to prolonged cultivation and lack of protection.To determine long-term trends of precipi-tation and rainfall erosivity over NEC during the latest decades,daily precipitation for the entire year during 1961-2020 and hourly precipitation for the warm season(May to September)during 1971-2020 were collected for 192 and 126 stations,respectively.Three seasons,including the cold season(October to April),early warm season(May to June),and late warm season(July to September)were divided according to the combination of precipitation and vegetation.Results demonstrate:(1)Daily precipita-tion reveals total precipitation and rainfall erosivity in the cold season and early warm season increase significantly at relative rates of 3.1%-6.1%compared with the average during 1961-2020,and those in the late warm season decrease insignificantly.(2)Hourly precipitation reveals storms occurring in the early and late warm seasons have undergone significant increasing changes,which shift towards longer storm duration,larger amount,peak intensity,kinetic energy,and rainfall erosivity during 1971-2020.Moreover,the frequency of extreme storms increased.(3)Rainfall erosivities estimated from daily pre-cipitation during 1971-2020 increase insignificantly for the early and late warm season,whereas those from hourly precipitation increase significantly(6.1%and 5.5%,respectively),which indicates daily precipitation may not be able to capture the trend fully under the warming background,and precipi-tation at higher resolutions than the daily scale is necessary to detect trends of rainfall erosivity more accurately.
基金support provided by Basrah University and the Education Ministry of Iraq towardshis visit to Huazhong University of Science and Technology,China
文摘An adaptive neuro-fuzzy inference system （ANFIS） is introduced to predict the dynamic behavior of beams. The effects of axial forces and large displacements are considered in the analysis. A database of tests for the dynamic characteristics of beams is developed from the experimental tests. The responses of nonlinear vibration force for the single and multiple-stepped beams are calculated from the finite element method （FEM）, experimental tests and neuro-fuzzy model for comparison. The neuro-fuzzy model provides a general framework for the combination of neural networks and fuzzy logic. It is more flexible with more options of incorporating the fuzzy nature of the real-world system and is an useful estimation tool for the dynamic characteristics of beams. Therefore, ANFIS can be a useful tool for dynamic behaviour analysis of multiple-stepped beams subjected to axial loads and large displacement.
基金supported by the National Natural Science Foundation of China(Grant Nos.11225524,11675101,and 11505113)the National Basic Research Program of China(Grant No.2013CB834401)+1 种基金Shanghai Key Laboratory(Grant No.11DZ2260700)the Program of Shanghai Academic/Technology Research Leader(Grant No.16XD1401600)
文摘Garvey-Kelson mass relations connect nuclear masses of neighboring nuclei within high accuracy, and provide us with convenient tools in predicting unknown masses by extrapolations from existent experimental data. In this paper we investigate optimal"channels" of the Garvey-Kelson relations in extrapolation to the unknown regions, and tabulate our predicted masses by using these optimized channels of the Garvey-Kelson relations.
基金Project supported by the National Natural Science Foundation of China(Nos.11572132 and 11572137)
文摘Based on the continuity of the derivatives of the Non-Uniform Rational B-Splines (NURBS) curve and the Jaumann strain measure, the present paper adopted the position coordinates of the control points as the degrees of freedom and developed a planar rotation-free Euler-Bernoulli beam element for isogeometric analysis, where the derivatives of the field variables with respect to the arc-length were expressed as the sum of the weighted sum of the position coordinates of the control points, and the NURBS basis functions were used as the weight functions. Furthermore, the concept of bending strip was used to involve the rigid connection between multiple patches. Several typical examples with geometric nonlinearities were used to demonstrate the accuracy and effectiveness of the proposed algorithm. The presented formulation fully accounts for the geometric nonlinearities and can be used to study the snap-through and snap-back phenomena of flexible beams.
基金The National Natural Science Foundation of China supported this work(82171448,82201613).
文摘Background In the new International League Against Epilepsy(ILAE)classification of seizure types,generalized seizures such as absence seizures(ASs)may originate from a focal point and rapidly spread to the bilaterally distributed brain network.Increasing evidence from animal and clinical studies has indicated that focal changes may occur prior to ASs;however,the relationship of ASs with epileptogenic lesions remains unclear.Methods We retrospectively collected and analyzed the clinical,imaging,and electrophysiological data of 16 patients who had ASs and structural lesions with seizure-free outcomes after lesion resection.Results In semiology analysis,nine patients displayed focal onset;only two patients showed simple ASs,and seizure types other than ASs were observed in the remaining patients.On ictal electroencephalography(EEG),four patients showed bilateral synchronous symmetric 3 Hz generalized spike-wave discharges(GSWDs),and the remaining patients showed bilateral 1.5–2.5 Hz GSWDs.Moreover,most patients(13/16,81.3%)exhibited focal features in addition to ASs,while interictal EEG was the same in 12 patients.Furthermore,on stereoelectroencephalogram(SEEG),2/5 patients showed focal discharges before bilateral burst GSWDs.Additionally,all patients had structural lesions on imaging.In four typical AS patients,the lesions were located in deep brain regions.Notably,in 9 patients(9/16,56%),the lesions were located in the posterior cortex.All patients underwent lesion resection and had seizure-free outcomes during follow-up,and intelligence quotient(IQ)also improved by 10.71±3.90 one year after surgery.Conclusions Patients with lesion-related epilepsy may present with ASs that have a focal onset and are associated with good surgical outcomes.
