This paper studies the coupling mechanism between the nonlinear stiffness and damping coefficients of Active Elastic Support/Dry Friction Damper(AESDFD)and rotor system.First,parameters for evaluating the vibration re...This paper studies the coupling mechanism between the nonlinear stiffness and damping coefficients of Active Elastic Support/Dry Friction Damper(AESDFD)and rotor system.First,parameters for evaluating the vibration reduction characteristics are proposed to facilitate the design of the AESDFD.To achieve this,the nonlinear friction force is initially represented as equivalent stiffness and damping coefficients,based on the ball-plate friction model.Second,three evaluation parameters—optimal slipping displacement,loss factor,and controllability—are proposed to reveal the vibration reduction characteristics of the AESDFD,alongside determining the optimal normal force.Subsequently,the finite element method,in conjunction with the ball-plate friction model,is introduced to formulate the governing equation of a low-pressure rotor system equipped with AESDFDs.The steady-state responses of the AESDFDs-rotor system are solved using the harmonic balance method combined with an efficient iteration method.Finally,the solutions are validated on the AESDFDs-rotor system both numerically and experimentally.The results indicate that controllability effectively assesses the vibration reduction performance of the AESDFD and is relatively insensitive to variations in low normal force.Away from the critical speed,the AESDFD suppresses vibration by altering the resonance position of the rotor system through its stiffness coefficient.Near the critical speed,vibration reduction is achieved primarily through energy dissipation by the damping coefficient.If the loss factor is less than one,the stiffness coefficient can diminish the vibration reduction effect of the damping coefficient.Notably,the optimal normal force of the AESDFD achieves optimal vibration reduction effect.This study reveals that changes in rotor system unbalance do not affect the vibration reduction characteristics of the AESDFD,with the same upper limit to the vibration reduction effect of the AESDFD.展开更多
This paper is devoted to proving the polynomial mixing for a weakly damped stochastic nonlinear Schröodinger equation with additive noise on a 1D bounded domain.The noise is white in time and smooth in space.We c...This paper is devoted to proving the polynomial mixing for a weakly damped stochastic nonlinear Schröodinger equation with additive noise on a 1D bounded domain.The noise is white in time and smooth in space.We consider both focusing and defocusing nonlinearities,with exponents of the nonlinearityσ∈[0,2)andσ∈[0,∞),and prove the polynomial mixing which implies the uniqueness of the invariant measure by using a coupling method.In the focusing case,our result generalizes the earlier results in[12],whereσ=1.展开更多
In recent years,with the increasing attention to issues related to carbon emissions,such as carbon tariffs and government netzero carbon emission policies,carbon emissions have become an important indicator that is be...In recent years,with the increasing attention to issues related to carbon emissions,such as carbon tariffs and government netzero carbon emission policies,carbon emissions have become an important indicator that is being prioritized by governments worldwide.The Google Environmental Insights Explorer(EIE)tool has been developed to facilitate the collection and integration of data in this context.This study focuses on Tainan City and utilizes EIE to analyze greenhouse gas emissions from transportation.By using EIE,the study obtains data on greenhouse gas emissions from transportation activities in Tainan City.EIE utilizes data collected by Google and simulation functions to estimate data based on actual measurements of transportation activities.This tool saves time and resources by eliminating the need for on-site investigations while providing data that closely represent the real emissions from transportation activities in urban areas.Transportation vehicles contribute to greenhouse gas emissions in two ways:through direct combustion of fossil fuels and through the consumption of electricity in electric vehicles(EVs).The level of greenhouse gas emissions in a city’s transportation industry depends on factors such as transportation modes,fuel types,fleet age and energy efficiency,total distance traveled,and annual mileage.EIE estimates the greenhouse gas emissions from Tainan City’s transportation industry in 2022 to be 3,320,000 metric tons,including emissions from buses,motorcycles,cars,walking,railways,bicycles,and other modes of transportation.展开更多
We investigate the blow-up effect of solutions for a non-homogeneous wave equation u_(tt)−∆u−∆u_(t)=I_(0+)^(α)(|u|^(p))+ω(x),where p>1,0≤α<1 andω(x)with∫_(R)^(N)ω(x)dx>0.By a way of combining the argum...We investigate the blow-up effect of solutions for a non-homogeneous wave equation u_(tt)−∆u−∆u_(t)=I_(0+)^(α)(|u|^(p))+ω(x),where p>1,0≤α<1 andω(x)with∫_(R)^(N)ω(x)dx>0.By a way of combining the argument by contradiction with the test function techniques,we prove that not only any non-trivial solution blows up in finite time under 0<α<1,N≥1 and p>1,but also any non-trivial solution blows up in finite time underα=0,2≤N≤4 and p being the Strauss exponent.展开更多
目的:基于“湿热伤肾”学说探究加味二妙丸改善糖尿病肾脏疾病难治性蛋白尿的疗效和作用机制。方法:选取2022年1月—2025年1月于南京大学医学院附属鼓楼医院中医科以及肾内科的糖尿病肾脏疾病患者126例。采用随机数字表法分为治疗组和...目的:基于“湿热伤肾”学说探究加味二妙丸改善糖尿病肾脏疾病难治性蛋白尿的疗效和作用机制。方法:选取2022年1月—2025年1月于南京大学医学院附属鼓楼医院中医科以及肾内科的糖尿病肾脏疾病患者126例。采用随机数字表法分为治疗组和对照组,每组63例。对照组给予常规基础治疗。治疗组在常规基础治疗上应用加味二妙丸治疗。分别于入组当天及治疗8周,评估患者中医证候积分情况[口渴多饮、肢体浮肿、口中黏腻、脘腹胀满]、检测尿蛋白谱指标[24 h尿蛋白(24 h UPro)、尿白蛋白(UAlb)、尿肾损伤分子-1(UKim-1)、尿N-乙酰-β-D-葡萄糖苷酶(UNAG)]、代谢组学指标[棕榈酸、左旋肉碱、磷脂酰胆碱(PC)、二酰甘油(Dg)]、肾功能指标[血肌酐(Scr)、血尿素氮(BUN)]、安全性指标[红细胞(RBC)、丙氨酸氨基转移酶(ALT)、白蛋白(Alb)、糖化血红蛋白(HbA1c)]水平。对比两组临床疗效。结果:治疗后,与对照组比较,治疗组口渴多饮、肢体浮肿、口中黏腻、脘腹胀满积分、24 h UPro、UAlb、UKim-1、UNAG、棕榈酸、Scr、BUN水平均降低(P<0.05,P<0.01),左旋肉碱、PC、Dg水平升高(P<0.05,P<0.01)。与对照组比较,治疗组总有效率升高(P<0.01)。结论:基于“湿热伤肾”学说在常规基础治疗上,应用加味二妙丸首次在单中心随机对照研究中证实其可显著改善糖尿病肾脏疾病难治性蛋白尿,调节代谢组学指标并保护肾功能,且安全性高;棕榈酸、左旋肉碱、PC、Dg可能是加味二妙丸治疗糖尿病肾脏疾病难治性蛋白尿的药物靶标。展开更多
基金supported by the National Science and Technology Major Project,China,the China Scholarship Council(No.202306290109)National Natural Science Foundation of China(Nos.52472456 and 52361165620)。
文摘This paper studies the coupling mechanism between the nonlinear stiffness and damping coefficients of Active Elastic Support/Dry Friction Damper(AESDFD)and rotor system.First,parameters for evaluating the vibration reduction characteristics are proposed to facilitate the design of the AESDFD.To achieve this,the nonlinear friction force is initially represented as equivalent stiffness and damping coefficients,based on the ball-plate friction model.Second,three evaluation parameters—optimal slipping displacement,loss factor,and controllability—are proposed to reveal the vibration reduction characteristics of the AESDFD,alongside determining the optimal normal force.Subsequently,the finite element method,in conjunction with the ball-plate friction model,is introduced to formulate the governing equation of a low-pressure rotor system equipped with AESDFDs.The steady-state responses of the AESDFDs-rotor system are solved using the harmonic balance method combined with an efficient iteration method.Finally,the solutions are validated on the AESDFDs-rotor system both numerically and experimentally.The results indicate that controllability effectively assesses the vibration reduction performance of the AESDFD and is relatively insensitive to variations in low normal force.Away from the critical speed,the AESDFD suppresses vibration by altering the resonance position of the rotor system through its stiffness coefficient.Near the critical speed,vibration reduction is achieved primarily through energy dissipation by the damping coefficient.If the loss factor is less than one,the stiffness coefficient can diminish the vibration reduction effect of the damping coefficient.Notably,the optimal normal force of the AESDFD achieves optimal vibration reduction effect.This study reveals that changes in rotor system unbalance do not affect the vibration reduction characteristics of the AESDFD,with the same upper limit to the vibration reduction effect of the AESDFD.
基金supported by the National Key R&D Program of China(2023YFA1009200)the NSFC(11925102)the Liaoning Revitalization Talents Program(XLYC2202042)。
文摘This paper is devoted to proving the polynomial mixing for a weakly damped stochastic nonlinear Schröodinger equation with additive noise on a 1D bounded domain.The noise is white in time and smooth in space.We consider both focusing and defocusing nonlinearities,with exponents of the nonlinearityσ∈[0,2)andσ∈[0,∞),and prove the polynomial mixing which implies the uniqueness of the invariant measure by using a coupling method.In the focusing case,our result generalizes the earlier results in[12],whereσ=1.
文摘In recent years,with the increasing attention to issues related to carbon emissions,such as carbon tariffs and government netzero carbon emission policies,carbon emissions have become an important indicator that is being prioritized by governments worldwide.The Google Environmental Insights Explorer(EIE)tool has been developed to facilitate the collection and integration of data in this context.This study focuses on Tainan City and utilizes EIE to analyze greenhouse gas emissions from transportation.By using EIE,the study obtains data on greenhouse gas emissions from transportation activities in Tainan City.EIE utilizes data collected by Google and simulation functions to estimate data based on actual measurements of transportation activities.This tool saves time and resources by eliminating the need for on-site investigations while providing data that closely represent the real emissions from transportation activities in urban areas.Transportation vehicles contribute to greenhouse gas emissions in two ways:through direct combustion of fossil fuels and through the consumption of electricity in electric vehicles(EVs).The level of greenhouse gas emissions in a city’s transportation industry depends on factors such as transportation modes,fuel types,fleet age and energy efficiency,total distance traveled,and annual mileage.EIE estimates the greenhouse gas emissions from Tainan City’s transportation industry in 2022 to be 3,320,000 metric tons,including emissions from buses,motorcycles,cars,walking,railways,bicycles,and other modes of transportation.
基金Supported by National Natural Science Foundation of China(Grant No.62363005).
文摘We investigate the blow-up effect of solutions for a non-homogeneous wave equation u_(tt)−∆u−∆u_(t)=I_(0+)^(α)(|u|^(p))+ω(x),where p>1,0≤α<1 andω(x)with∫_(R)^(N)ω(x)dx>0.By a way of combining the argument by contradiction with the test function techniques,we prove that not only any non-trivial solution blows up in finite time under 0<α<1,N≥1 and p>1,but also any non-trivial solution blows up in finite time underα=0,2≤N≤4 and p being the Strauss exponent.
文摘目的:基于“湿热伤肾”学说探究加味二妙丸改善糖尿病肾脏疾病难治性蛋白尿的疗效和作用机制。方法:选取2022年1月—2025年1月于南京大学医学院附属鼓楼医院中医科以及肾内科的糖尿病肾脏疾病患者126例。采用随机数字表法分为治疗组和对照组,每组63例。对照组给予常规基础治疗。治疗组在常规基础治疗上应用加味二妙丸治疗。分别于入组当天及治疗8周,评估患者中医证候积分情况[口渴多饮、肢体浮肿、口中黏腻、脘腹胀满]、检测尿蛋白谱指标[24 h尿蛋白(24 h UPro)、尿白蛋白(UAlb)、尿肾损伤分子-1(UKim-1)、尿N-乙酰-β-D-葡萄糖苷酶(UNAG)]、代谢组学指标[棕榈酸、左旋肉碱、磷脂酰胆碱(PC)、二酰甘油(Dg)]、肾功能指标[血肌酐(Scr)、血尿素氮(BUN)]、安全性指标[红细胞(RBC)、丙氨酸氨基转移酶(ALT)、白蛋白(Alb)、糖化血红蛋白(HbA1c)]水平。对比两组临床疗效。结果:治疗后,与对照组比较,治疗组口渴多饮、肢体浮肿、口中黏腻、脘腹胀满积分、24 h UPro、UAlb、UKim-1、UNAG、棕榈酸、Scr、BUN水平均降低(P<0.05,P<0.01),左旋肉碱、PC、Dg水平升高(P<0.05,P<0.01)。与对照组比较,治疗组总有效率升高(P<0.01)。结论:基于“湿热伤肾”学说在常规基础治疗上,应用加味二妙丸首次在单中心随机对照研究中证实其可显著改善糖尿病肾脏疾病难治性蛋白尿,调节代谢组学指标并保护肾功能,且安全性高;棕榈酸、左旋肉碱、PC、Dg可能是加味二妙丸治疗糖尿病肾脏疾病难治性蛋白尿的药物靶标。
