Objective Post tuberculosis lung disease(PTLD)manifests in various forms,including tuberculosisassociated chronic obstructive pulmonary disease(TB-COPD),yet the clinical features of PTLD remain undercharacterized.This...Objective Post tuberculosis lung disease(PTLD)manifests in various forms,including tuberculosisassociated chronic obstructive pulmonary disease(TB-COPD),yet the clinical features of PTLD remain undercharacterized.This study aimed to assess longitudinal changes in lung function over a 5-year period and to identify predictors of airflow obstruction in a cohort of patients treated for active pulmonary TB.Methods Patients with active pulmonary TB were enrolled in this study and were followed during treatment,at treatment completion and five years post-treatment.Assessments included lung function and chest CT,analyzing longitudinal trends and airflow obstruction risk factors.Results Among 53 patients(mean age 36.9±13.9 years;64.2%male),7 patients(13.2%)exhibited airflow obstruction.At the 5-year follow-up,the mean FEV_(1)/FVC declined significantly(76.27%±12.04%vs.80.23%±11.02%,P<0.001)and 9 patients(17.0%)exhibited airflow obstruction.Seven of these patients predominantly showed air trapping consistent with small airway disease on chest CT,aligning with TB-COPD phenotype.Notably,four young-to-middle-aged patients(<60 years old)had persistent obstruction over the five years.Conclusion The initial test revealed that 13.2%of patients presented with airflow obstruction.By the 5-year follow-up,this proportion had increased to 17.0%,with most cases demonstrating imaging findings aligning with TB-COPD,even among younger,non-smoking individuals.These findings emphasize the importance of long-term follow-up and routine lung function assessments in TB survivors.展开更多
According to the Mindlin plate theory and the first-order piston theory,this work obtains accurate closed-form eigensolutions for the flutter problem of three-dimensional(3D)rectangular laminated panels.The governing ...According to the Mindlin plate theory and the first-order piston theory,this work obtains accurate closed-form eigensolutions for the flutter problem of three-dimensional(3D)rectangular laminated panels.The governing differential equations are derived by the Hamilton's variational principle,and then solved by the iterative Separation-of-Variable(i SOV)method,which are applicable to arbitrary combinations of homogeneous Boundary Conditions(BCs).However,only the simply-support,clamped and cantilever panels are considered in this work for the sake of clarity.With the closed-form eigensolutions,the flutter frequency,flutter mode and flutter boundary are presented,and the effect of shear deformation and aerodynamic damping on flutter frequencies is investigated.Besides,the relation between panel energy and the work of aerodynamic load is discussed.The numerical comparisons reveal the following.(A)The flutter eigenvalues obtained by the present method are accurate,validated by the Finite Element Method(FEM)and the Galerkin method.(B)When the span-chord ratio is larger than 3,simplifying a 3D panel to 2D(two-dimensional)panel is reasonable and the relative differences of the flutter points predicted by the two models are less than one percent.(C)The reciprocal relationship between the mechanical energy of the panel and the work done by aerodynamic load is verified by using the present flutter eigenvalues and modes,further indicating the high accuracy of the present solutions.(D)The coupling of shear deformation and aerodynamic damping prevents frequency coalescing.展开更多
Variable stiffness composite laminates(VSCLs)are promising in aerospace engineering due to their designable material properties through changing fiber angles and stacking sequences.Aiming to control the thermal postbu...Variable stiffness composite laminates(VSCLs)are promising in aerospace engineering due to their designable material properties through changing fiber angles and stacking sequences.Aiming to control the thermal postbuckling and nonlinear panel flutter motions of VSCLs,a full-order numerical model is developed based on the linear quadratic regulator(LQR)algorithm in control theory,the classical laminate plate theory(CLPT)considering von Kármán geometrical nonlinearity,and the first-order Piston theory.The critical buckling temperature and the critical aerodynamic pressure of VSCLs are parametrically investigated.The location and shape of piezoelectric actuators for optimal control of the dynamic responses of VSCLs are determined through comparing the norms of feedback control gain(NFCG).Numerical simulations show that the temperature field has a great effect on aeroelastic tailoring of VSCLs;the curvilinear fiber path of VSCLs can significantly affect the optimal location and shape of piezoelectric actuator for flutter suppression;the unstable panel flutter and the thermal postbuckling deflection can be suppressed effectively through optimal design of piezoelectric patches.展开更多
目的:为了提高医疗设备验收的信息化管理水平,设计多端协同医疗设备验收管理系统。方法:多端协同医疗设备验收管理系统采用前后端分离的设计架构,前端采用跨平台框架Flutter和Dart语言开发,后端采用Tornado 6.1框架和Python语言开发,前...目的:为了提高医疗设备验收的信息化管理水平,设计多端协同医疗设备验收管理系统。方法:多端协同医疗设备验收管理系统采用前后端分离的设计架构,前端采用跨平台框架Flutter和Dart语言开发,后端采用Tornado 6.1框架和Python语言开发,前端与后端服务之间的通信遵循RESTful设计原则,通过超文本传输协议(hypertext transfer protocol,HTTP)请求进行交互。整个系统包括用户管理、基础信息管理、验收管理3个功能模块。结果:该系统实现了医疗设备验收过程的信息化管理,支持跨平台管理验收报告及相关附件、医疗器械注册证等内容,提高了验收的工作质量与效率。结论:该系统实现了医疗设备验收的多端协同管理,为医院医疗设备管理的数字化和智能化转型奠定了基础。展开更多
Hereby we describe a case of LAF developed after a surgical Maze procedure that demonstrates the importance of a systematic approach to mapping and ablating atypical atrial flutter to prevent a recurrence of symptomat...Hereby we describe a case of LAF developed after a surgical Maze procedure that demonstrates the importance of a systematic approach to mapping and ablating atypical atrial flutter to prevent a recurrence of symptomatic arrhythmia. In patients with previous cardiac surgery procedures, and in particular after a surgical maze, there are many different potential LA reentry circuits that involve various pathways. Both activation mapping and entrainment mapping were performed in order to identify the critical isthmus of the circuit and to effectively terminate the arrhythmia.展开更多
Atrial fibrillation(AF)/atrial flutter(AFL)is the most common sustained cardiac arrhythmia.The known risk factors for developing AF/AFL include age,structural heart disease,hypertension,diabetes mellitus,or hyperthyro...Atrial fibrillation(AF)/atrial flutter(AFL)is the most common sustained cardiac arrhythmia.The known risk factors for developing AF/AFL include age,structural heart disease,hypertension,diabetes mellitus,or hyperthyroidism.This study aims to attribute the trends in AF/AFL-related mortalities over the past two decades 1999-2020 concerning race and sex and disparity among them.To the best of our knowledge,this is the first study that estimates the trends and mortality due to AF/AFL from 1999-2020 in older adults in the United States.In this 21-year analysis of mortality data,we found a constant increase in mortality rates due to AF/AFL in older adults.From 1999 to 2020,the overall mortality in older adults aged 65 and above,regardless of sex and race,is found to be almost doubled i.e.about a 50.2%increase in the number of deaths due to AF/AFL.Furthermore,other confounding risk factors such has obesity,prior myocardial infarction,inflammation,hypertension,birth weight,diabetes mellitus,hyperthyroidism,hormone replacement therapy in menopausal women increases the risk in the occurrence or recurrent occurrence of AF.展开更多
This article discusses the evolving real-world practice using nitazoxanide,nonsteroidal anti-inflammatory drugs(NSAIDs)and/or azithromycin(Kelleni’s protocol)to manage the evolving manifestations of severe acute resp...This article discusses the evolving real-world practice using nitazoxanide,nonsteroidal anti-inflammatory drugs(NSAIDs)and/or azithromycin(Kelleni’s protocol)to manage the evolving manifestations of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)Omicron EG.5.1,its descendant HV.1 as well as BA.2.86 and its descendant JN.1 subvariants in Egypt in 2024.These subvariants are well-known for their highly evolved immune-evasive properties and the manifestations include some peculiar manifestations as persistent cough besides high fever in young children as well as high fever,persistent severe cough,change of voice,loss of taste and smell,epigastric pain,nausea,vomiting,diarrhea,generalized malaise and marked bone aches in adults including the high-risk groups.It’s suggested that the ongoing SARS-CoV-2 evolution is continuing to mostly affect the high-risk groups of patients,to some of whom we’ve also successfully prescribed nitazoxanide and/or NSAIDs for post-exposure prophylaxis of all household contacts.We also continue to recommend starting the immune-modulatory antiviral Kelleni’s protocol as soon as possible in the course of infection and adjusting it in a personalized manner to be more aggressive from the beginning for the high risk patients,at least until the currently encountered surge of infections subsides.展开更多
Cardiac arrest(CA)is a critical condition in the field of cardiovascular medicine.Despite successful resuscitation,patients continue to have a high mortality rate,largely due to post CA syndrome(PCAS).However,the inju...Cardiac arrest(CA)is a critical condition in the field of cardiovascular medicine.Despite successful resuscitation,patients continue to have a high mortality rate,largely due to post CA syndrome(PCAS).However,the injury and pathophysiological mechanisms underlying PCAS remain unclear.Experimental animal models are valuable tools for exploring the etiology,pathogenesis,and potential interventions for CA and PCAS.Current CA animal models include electrical induction of ventricular fibrillation(VF),myocardial infarction,high potassium,asphyxia,and hemorrhagic shock.Although these models do not fully replicate the complexity of clinical CA,the mechanistic insights they provide remain highly relevant,including post-CA brain injury(PCABI),post-CA myocardial dysfunction(PAMD),systemic ischaemia/reperfusion injury(IRI),and the persistent precipitating pathology.Summarizing the methods of establishing CA models,the challenges encountered in the modeling process,and the mechanisms of PCAS can provide a foundation for developing standardized CA modeling protocols.展开更多
Deep in the Tengger Desert of Inner Mongolia autonomous region,surrounded by sand as far as the eye can see,lies the world's loneliest post office.Measuring only 15 square meters,the wooden post office doesn't...Deep in the Tengger Desert of Inner Mongolia autonomous region,surrounded by sand as far as the eye can see,lies the world's loneliest post office.Measuring only 15 square meters,the wooden post office doesn't get too many visitors anyway.But after being abandoned for over 35 years,it actually doesn't look half bad.展开更多
Quantum flutter is a ubiquitous phenomenon which can be observed from the fast moving impurity injected into a fermionic or bosonic medium of quantum liquid.In this scenario,one usually considers a medium of a fully p...Quantum flutter is a ubiquitous phenomenon which can be observed from the fast moving impurity injected into a fermionic or bosonic medium of quantum liquid.In this scenario,one usually considers a medium of a fully polarized state and injects a spin-flipped impurity as the initial state.When the initial velocity of the impurity is beyond the intrinsic sound velocity of the medium,the impurity momentum dramatically exhibits a long-lived periodic oscillation with the periodicity remaining invariant with respect to the initial velocity.In this paper,we show that such a novel phenomenon can be explained by a linear Luttinger liquid coupled to a deep hole in the Fermi sea.Once the deep hole excitations are involved and the impurity momentum surpasses the Fermi momentum,the propagator thus displays a periodic oscillation after a quick relaxation decay.The oscillation periodicity is solely determined by the energy of the deepest hole excitation.Our result provides deep insights into the dynamical behavior of quantum impurities immersed into one-dimensional quantum liquids.展开更多
Flutter and forced response, as two main branches of aeroelasticity, can lead to high-cycle fatigue failure of turbomachinery blades. Efficiently and accurately assessing aeroelastic performance of turbomachinery blad...Flutter and forced response, as two main branches of aeroelasticity, can lead to high-cycle fatigue failure of turbomachinery blades. Efficiently and accurately assessing aeroelastic performance of turbomachinery blades is essential in the routine design. In this work, the Time Collocation Method (TCM) which uses the cubic B-spline to approximate flow variables is first thoroughly studied and then combined with the moving grid technique to analyze aeroelastic flow fields. To showcase its advantage over the Harmonic Balance (HB) method which uses a truncated Fourier series to approximately represent flow variables, a matrix analysis of the one-dimensional advection equation is first performed. The results of stability analysis are verified by two test cases: the Durham linear oscillating turbine cascade and a two-blade-row transonic compressor. The vibration of the blade of the first case is driven by a motor while the excitation force of the second case comes from blade row interaction. The results show that the time collocation method has a faster convergence rate and is more stable than the harmonic balance method, especially for cases with a large maximum grid reduced frequency. More importantly, the time collocation method is capable of accurately predicting aeroelastic performance of turbomachinery blades.展开更多
An aileron is a crucial control surface for rolling.Any jitter or shaking caused by the aileron mechatronics could have catastrophic consequences for the aircraft’s stability,maneuverability,safety,and lifespan.This ...An aileron is a crucial control surface for rolling.Any jitter or shaking caused by the aileron mechatronics could have catastrophic consequences for the aircraft’s stability,maneuverability,safety,and lifespan.This paper presents a robust solution in the form of a fast flutter suppression digital control logic of edge computing aileron mechatronics(ECAM).We have effectively eliminated passive and active oscillating response biases by integrating nonlinear functional parameters and an antiphase hysteresis Schmitt trigger.Our findings demonstrate that self-tuning nonlinear parameters can optimize stability,robustness,and accuracy.At the same time,the antiphase hysteresis Schmitt trigger effectively rejects flutters without the need for collaborative navigation and guidance.Our hardware-in-the-loop simulation results confirm that this approach can eliminate aircraft jitter and shaking while ensuring expected stability and maneuverability.In conclusion,this nonlinear aileron mechatronics with a Schmitt positive feedback mechanism is a highly effective solution for distributed flight control and active flutter rejection.展开更多
In this paper,a series of flutter simulations are carried out to investigate the effects of split drag rudder(SDR)on the transonic flutter characteristic of rigid NACA 64A010.A structural dynamic model addressing two-...In this paper,a series of flutter simulations are carried out to investigate the effects of split drag rudder(SDR)on the transonic flutter characteristic of rigid NACA 64A010.A structural dynamic model addressing two-degree-of-freedom pitch-plunge aeroelastic oscillations was coupled with the unsteady Reynolds-averaged Navier-Stokes equations to perform flutter simulation.Meanwhile,the influence mechanism of SDR on flutter boundary is explained through aerodynamic work and the correlated shock wave location.The results show that the SDR delays the shock wave shifting downstream,and the Mach number corresponding to reaching freeze region increases as the split angle increases.Therefore,the peak value of aerodynamic moment coefficient amplitude and the sharp ascent process of phase occurs at higher Mach number,which leads to the delay in the occurrence of the transonic dip.Besides,before the transonic dip of airfoil without SDR occurs,the aerodynamic moment phase of airfoil with the SDR decreases slowly due to the decrease in the speed of shock wave moving downstream.This results in an increased flutter speed when employing the SDR before the transonic dip of airfoil without SDR occurs.Meanwhile,the effects of asymmetric split angles on the transonic flutter characteristics are also investigated.Before the transonic dip of airfoil without SDR occurs,the flutter characteristic is dominated by the smaller split angle.展开更多
Polyvinyl chloride(PVC)is one of the most widely used plastic materials worldwide,particularly in long-life applications such as construction materials.However,recycling options for PVC waste remain limited,as convent...Polyvinyl chloride(PVC)is one of the most widely used plastic materials worldwide,particularly in long-life applications such as construction materials.However,recycling options for PVC waste remain limited,as conventional methods often degrade material quality or generate environmentally hazardous byproducts.In this study,we demonstrate an efficient process to convert PVC into new polymers with variable aromatic groups,using triethylsilane as the reductant in different solvents.This approach enables the production of polymers analogous to functionalized polyethylene(PE),which are typically challenging to obtain through conventional copolymerization or direct post-modification of C-H bonds in PE.The resulting polymers exhibit tunable thermal and mechanical properties depending on the introduced aromatic groups,which not only enhance the sustainable valorization of PVC waste,but also provide an opportunity for the synthesis of new functionalized polymers.展开更多
Stall flutter poses great challenges to flight safety.To alleviate this problem,a steady blowing control considering the perturbation and wake-induced vibration at a large angle of attack is developed in this paper,wh...Stall flutter poses great challenges to flight safety.To alleviate this problem,a steady blowing control considering the perturbation and wake-induced vibration at a large angle of attack is developed in this paper,where two blowings are configured on upper and lower tail surfaces to suppress the stall flutter.The stall flutter with one-degree-of-freedom is first evaluated by numerical simulation.The equation of motion for stall flutter is solved by the Newmark-β method.Then,the stall flutter responses for five blowing speeds,i.e.,0,4,12,20,and 28 m/s under the airspeed range of 3–9 m/s,are studied in detail.The stall flutter suppression mechanism can be summarized as follows:a large blowing speed can inject energy into the boundary layer and enhance the high-pressure zone,which delays the flow separation on the suction surface.In this way,the formation of the leading-edge separation vortex is suppressed.Thus,the dynamic stall vortex is weakened and accelerates shedding.In addition,the driving moment is reduced,which leads to a decrement in the stall flutter amplitude.When the blowing speed is 28 m/s(stall flutter amplitude=0.1357 rad),compared with uncontrolled case(stall flutter amplitude=0.6002 rad),the amplitude can decrease by 77.39%,which demonstrates the effectiveness of the proposed steady blowing based active control strategy.展开更多
This study experimentally investigates the hydrodynamic characteristics,geometric configurations,fluttering motions of the codend,and the instantaneous flow fields inside and around the codend,with and without a liner...This study experimentally investigates the hydrodynamic characteristics,geometric configurations,fluttering motions of the codend,and the instantaneous flow fields inside and around the codend,with and without a liner,under varying catch sizes and inflow velocities.A proper orthogonal decomposition method is employed to extract phase-averaged mean properties of unsteady turbulent flows from flow measurement data obtained using an electromagnetic current velocity meter inside and around the codend.The results reveal that as catch size increases,the drag force,codend motion,Reynolds number,and codend volume increase while the drag coefficient decreases.Owing to the codend shape and pronounced motion,a complex fluid–structure interaction occurs,demonstrating a strong correlation between drag force and codend volume.The oscillation amplitudes of the hydrodynamic forces and codend motions increase with increasing catch size,and their oscillations mainly involve low-frequency activity.A significant reduction in the flow field occurs inside and around the unlined codend without a catch.The flow field is 5.81%,14.39%,and 27.01%lower than the unlined codend with a catch,the codend with a liner but without a catch,and the codend with both a liner and a catch,respectively.Fourier analysis reveals that the codend motions and hydrodynamic forces are mainly characterized by low-frequency activity and are synchronized with the unsteady turbulent flow street.Furthermore,the proper orthogonal decomposition results reveal the development of unsteady turbulent flow inside and around the codend,driven by flow passage blockage caused by the presence of the liner,intense codend motions,and the catch.Understanding the hydrodynamic characteristics and flow instabilities inside and around the codend,particularly those associated with its fluttering motions,is crucial for optimizing trawl design and improving trawl selectivity.展开更多
Advanced propulsion systems experience critical challenges under extreme service conditions,including aerodynamic loads and thermal loads.Especially,flutter stability is a key bottleneck restricting the design and saf...Advanced propulsion systems experience critical challenges under extreme service conditions,including aerodynamic loads and thermal loads.Especially,flutter stability is a key bottleneck restricting the design and safe op⁃eration of hot structures in advanced propulsion systems employing ceramic matrix composites(CMCs).Compared to traditional nickel-based alloys,CMCs offer superior high-temperature resistance and specific strength,making them ideal for next-generation engine hot structures.The inherent anisotropy,heterogeneity,and complex nonlinear behav⁃ior of CMCs,coupled with extreme operating environments,result in strong multi-physics interactions,including aero-thermo-structural,thermo-mechanical,and damage-aeroelastic coupling.These complexities significantly com⁃plicate vibration stability and flutter analysis.The recent research progresses on these problems are systematically ex⁃amined,focusing on multi-field coupling mechanisms,material constitutive and damage evolution models,multi-scale modeling methods,coupled solution strategies,and the influence of key parameters on flutter characteristics.The current challenges are highlighted,including the complexity of high-temperature nonlinear modeling,the effi⁃ciency of multi-field coupling calculations,and the multi-scale modeling of complex weaving structures.Finally,an outlook on future development directions is presented to provide theoretical support for the design and safety assess⁃ment of hot structures of advanced CMCs.展开更多
基金supported by the National Science and Technology Major Project for the Prevention and Control of Emerging and Major Infectious Diseases[2025ZD01908702]Peking University Medicine Fund of Fostering Young Scholars’Scientific&Technological innovation[BMU2024YFJHP014]supported by Fundamental Research Funds for the Central Universities+1 种基金Key Clinical Projects of Peking University Third Hospital[BYSYZD2022014]Peking University Third Hospital[2025024].
文摘Objective Post tuberculosis lung disease(PTLD)manifests in various forms,including tuberculosisassociated chronic obstructive pulmonary disease(TB-COPD),yet the clinical features of PTLD remain undercharacterized.This study aimed to assess longitudinal changes in lung function over a 5-year period and to identify predictors of airflow obstruction in a cohort of patients treated for active pulmonary TB.Methods Patients with active pulmonary TB were enrolled in this study and were followed during treatment,at treatment completion and five years post-treatment.Assessments included lung function and chest CT,analyzing longitudinal trends and airflow obstruction risk factors.Results Among 53 patients(mean age 36.9±13.9 years;64.2%male),7 patients(13.2%)exhibited airflow obstruction.At the 5-year follow-up,the mean FEV_(1)/FVC declined significantly(76.27%±12.04%vs.80.23%±11.02%,P<0.001)and 9 patients(17.0%)exhibited airflow obstruction.Seven of these patients predominantly showed air trapping consistent with small airway disease on chest CT,aligning with TB-COPD phenotype.Notably,four young-to-middle-aged patients(<60 years old)had persistent obstruction over the five years.Conclusion The initial test revealed that 13.2%of patients presented with airflow obstruction.By the 5-year follow-up,this proportion had increased to 17.0%,with most cases demonstrating imaging findings aligning with TB-COPD,even among younger,non-smoking individuals.These findings emphasize the importance of long-term follow-up and routine lung function assessments in TB survivors.
基金support of the National Natural Science Foundation of China(No.12172023)。
文摘According to the Mindlin plate theory and the first-order piston theory,this work obtains accurate closed-form eigensolutions for the flutter problem of three-dimensional(3D)rectangular laminated panels.The governing differential equations are derived by the Hamilton's variational principle,and then solved by the iterative Separation-of-Variable(i SOV)method,which are applicable to arbitrary combinations of homogeneous Boundary Conditions(BCs).However,only the simply-support,clamped and cantilever panels are considered in this work for the sake of clarity.With the closed-form eigensolutions,the flutter frequency,flutter mode and flutter boundary are presented,and the effect of shear deformation and aerodynamic damping on flutter frequencies is investigated.Besides,the relation between panel energy and the work of aerodynamic load is discussed.The numerical comparisons reveal the following.(A)The flutter eigenvalues obtained by the present method are accurate,validated by the Finite Element Method(FEM)and the Galerkin method.(B)When the span-chord ratio is larger than 3,simplifying a 3D panel to 2D(two-dimensional)panel is reasonable and the relative differences of the flutter points predicted by the two models are less than one percent.(C)The reciprocal relationship between the mechanical energy of the panel and the work done by aerodynamic load is verified by using the present flutter eigenvalues and modes,further indicating the high accuracy of the present solutions.(D)The coupling of shear deformation and aerodynamic damping prevents frequency coalescing.
基金Project(JCYJ20190808175801656)supported by the Science and Technology Innovation Commission of Shenzhen,ChinaProject(2021M691427)supported by Postdoctoral Science Foundation of ChinaProject(9680086)supported by the City University of Hong Kong,China。
文摘Variable stiffness composite laminates(VSCLs)are promising in aerospace engineering due to their designable material properties through changing fiber angles and stacking sequences.Aiming to control the thermal postbuckling and nonlinear panel flutter motions of VSCLs,a full-order numerical model is developed based on the linear quadratic regulator(LQR)algorithm in control theory,the classical laminate plate theory(CLPT)considering von Kármán geometrical nonlinearity,and the first-order Piston theory.The critical buckling temperature and the critical aerodynamic pressure of VSCLs are parametrically investigated.The location and shape of piezoelectric actuators for optimal control of the dynamic responses of VSCLs are determined through comparing the norms of feedback control gain(NFCG).Numerical simulations show that the temperature field has a great effect on aeroelastic tailoring of VSCLs;the curvilinear fiber path of VSCLs can significantly affect the optimal location and shape of piezoelectric actuator for flutter suppression;the unstable panel flutter and the thermal postbuckling deflection can be suppressed effectively through optimal design of piezoelectric patches.
文摘目的:为了提高医疗设备验收的信息化管理水平,设计多端协同医疗设备验收管理系统。方法:多端协同医疗设备验收管理系统采用前后端分离的设计架构,前端采用跨平台框架Flutter和Dart语言开发,后端采用Tornado 6.1框架和Python语言开发,前端与后端服务之间的通信遵循RESTful设计原则,通过超文本传输协议(hypertext transfer protocol,HTTP)请求进行交互。整个系统包括用户管理、基础信息管理、验收管理3个功能模块。结果:该系统实现了医疗设备验收过程的信息化管理,支持跨平台管理验收报告及相关附件、医疗器械注册证等内容,提高了验收的工作质量与效率。结论:该系统实现了医疗设备验收的多端协同管理,为医院医疗设备管理的数字化和智能化转型奠定了基础。
文摘Hereby we describe a case of LAF developed after a surgical Maze procedure that demonstrates the importance of a systematic approach to mapping and ablating atypical atrial flutter to prevent a recurrence of symptomatic arrhythmia. In patients with previous cardiac surgery procedures, and in particular after a surgical maze, there are many different potential LA reentry circuits that involve various pathways. Both activation mapping and entrainment mapping were performed in order to identify the critical isthmus of the circuit and to effectively terminate the arrhythmia.
文摘Atrial fibrillation(AF)/atrial flutter(AFL)is the most common sustained cardiac arrhythmia.The known risk factors for developing AF/AFL include age,structural heart disease,hypertension,diabetes mellitus,or hyperthyroidism.This study aims to attribute the trends in AF/AFL-related mortalities over the past two decades 1999-2020 concerning race and sex and disparity among them.To the best of our knowledge,this is the first study that estimates the trends and mortality due to AF/AFL from 1999-2020 in older adults in the United States.In this 21-year analysis of mortality data,we found a constant increase in mortality rates due to AF/AFL in older adults.From 1999 to 2020,the overall mortality in older adults aged 65 and above,regardless of sex and race,is found to be almost doubled i.e.about a 50.2%increase in the number of deaths due to AF/AFL.Furthermore,other confounding risk factors such has obesity,prior myocardial infarction,inflammation,hypertension,birth weight,diabetes mellitus,hyperthyroidism,hormone replacement therapy in menopausal women increases the risk in the occurrence or recurrent occurrence of AF.
文摘This article discusses the evolving real-world practice using nitazoxanide,nonsteroidal anti-inflammatory drugs(NSAIDs)and/or azithromycin(Kelleni’s protocol)to manage the evolving manifestations of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)Omicron EG.5.1,its descendant HV.1 as well as BA.2.86 and its descendant JN.1 subvariants in Egypt in 2024.These subvariants are well-known for their highly evolved immune-evasive properties and the manifestations include some peculiar manifestations as persistent cough besides high fever in young children as well as high fever,persistent severe cough,change of voice,loss of taste and smell,epigastric pain,nausea,vomiting,diarrhea,generalized malaise and marked bone aches in adults including the high-risk groups.It’s suggested that the ongoing SARS-CoV-2 evolution is continuing to mostly affect the high-risk groups of patients,to some of whom we’ve also successfully prescribed nitazoxanide and/or NSAIDs for post-exposure prophylaxis of all household contacts.We also continue to recommend starting the immune-modulatory antiviral Kelleni’s protocol as soon as possible in the course of infection and adjusting it in a personalized manner to be more aggressive from the beginning for the high risk patients,at least until the currently encountered surge of infections subsides.
基金supported by the National Key Research and Development Program(2021YFC3002205)the Postgraduate Research and Innovation Program of Tianjin Municipal Education Commission(2022BKY113),China.
文摘Cardiac arrest(CA)is a critical condition in the field of cardiovascular medicine.Despite successful resuscitation,patients continue to have a high mortality rate,largely due to post CA syndrome(PCAS).However,the injury and pathophysiological mechanisms underlying PCAS remain unclear.Experimental animal models are valuable tools for exploring the etiology,pathogenesis,and potential interventions for CA and PCAS.Current CA animal models include electrical induction of ventricular fibrillation(VF),myocardial infarction,high potassium,asphyxia,and hemorrhagic shock.Although these models do not fully replicate the complexity of clinical CA,the mechanistic insights they provide remain highly relevant,including post-CA brain injury(PCABI),post-CA myocardial dysfunction(PAMD),systemic ischaemia/reperfusion injury(IRI),and the persistent precipitating pathology.Summarizing the methods of establishing CA models,the challenges encountered in the modeling process,and the mechanisms of PCAS can provide a foundation for developing standardized CA modeling protocols.
文摘Deep in the Tengger Desert of Inner Mongolia autonomous region,surrounded by sand as far as the eye can see,lies the world's loneliest post office.Measuring only 15 square meters,the wooden post office doesn't get too many visitors anyway.But after being abandoned for over 35 years,it actually doesn't look half bad.
基金SW is supported by the HK GRF under Grant Nos.17306024 and 17313122the CRF under Grant No.C7012-21G+2 种基金a RGC Fellowship Award under No.HKU RFS2223-7S03XWG and ZHZ are supported by the NSFC key under Grant Nos.12134015,92365202,12121004,12175290the National Key R&D Program of China under Grant No.2022YFA1404102.
文摘Quantum flutter is a ubiquitous phenomenon which can be observed from the fast moving impurity injected into a fermionic or bosonic medium of quantum liquid.In this scenario,one usually considers a medium of a fully polarized state and injects a spin-flipped impurity as the initial state.When the initial velocity of the impurity is beyond the intrinsic sound velocity of the medium,the impurity momentum dramatically exhibits a long-lived periodic oscillation with the periodicity remaining invariant with respect to the initial velocity.In this paper,we show that such a novel phenomenon can be explained by a linear Luttinger liquid coupled to a deep hole in the Fermi sea.Once the deep hole excitations are involved and the impurity momentum surpasses the Fermi momentum,the propagator thus displays a periodic oscillation after a quick relaxation decay.The oscillation periodicity is solely determined by the energy of the deepest hole excitation.Our result provides deep insights into the dynamical behavior of quantum impurities immersed into one-dimensional quantum liquids.
基金supported by the Science Center for Gas Turbine Project,China(No.P2022-C-II-001-001)the National Science and Technology Major Project,Chinathe Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China(No.CX2022045).
文摘Flutter and forced response, as two main branches of aeroelasticity, can lead to high-cycle fatigue failure of turbomachinery blades. Efficiently and accurately assessing aeroelastic performance of turbomachinery blades is essential in the routine design. In this work, the Time Collocation Method (TCM) which uses the cubic B-spline to approximate flow variables is first thoroughly studied and then combined with the moving grid technique to analyze aeroelastic flow fields. To showcase its advantage over the Harmonic Balance (HB) method which uses a truncated Fourier series to approximately represent flow variables, a matrix analysis of the one-dimensional advection equation is first performed. The results of stability analysis are verified by two test cases: the Durham linear oscillating turbine cascade and a two-blade-row transonic compressor. The vibration of the blade of the first case is driven by a motor while the excitation force of the second case comes from blade row interaction. The results show that the time collocation method has a faster convergence rate and is more stable than the harmonic balance method, especially for cases with a large maximum grid reduced frequency. More importantly, the time collocation method is capable of accurately predicting aeroelastic performance of turbomachinery blades.
基金supported in part by the Aeronautical Science Foundation of China under Grant 2022Z005057001the Joint Research Fund of Shanghai Commercial Aircraft System Engineering Science and Technology Innovation Center under CASEF-2023-M19.
文摘An aileron is a crucial control surface for rolling.Any jitter or shaking caused by the aileron mechatronics could have catastrophic consequences for the aircraft’s stability,maneuverability,safety,and lifespan.This paper presents a robust solution in the form of a fast flutter suppression digital control logic of edge computing aileron mechatronics(ECAM).We have effectively eliminated passive and active oscillating response biases by integrating nonlinear functional parameters and an antiphase hysteresis Schmitt trigger.Our findings demonstrate that self-tuning nonlinear parameters can optimize stability,robustness,and accuracy.At the same time,the antiphase hysteresis Schmitt trigger effectively rejects flutters without the need for collaborative navigation and guidance.Our hardware-in-the-loop simulation results confirm that this approach can eliminate aircraft jitter and shaking while ensuring expected stability and maneuverability.In conclusion,this nonlinear aileron mechatronics with a Schmitt positive feedback mechanism is a highly effective solution for distributed flight control and active flutter rejection.
文摘In this paper,a series of flutter simulations are carried out to investigate the effects of split drag rudder(SDR)on the transonic flutter characteristic of rigid NACA 64A010.A structural dynamic model addressing two-degree-of-freedom pitch-plunge aeroelastic oscillations was coupled with the unsteady Reynolds-averaged Navier-Stokes equations to perform flutter simulation.Meanwhile,the influence mechanism of SDR on flutter boundary is explained through aerodynamic work and the correlated shock wave location.The results show that the SDR delays the shock wave shifting downstream,and the Mach number corresponding to reaching freeze region increases as the split angle increases.Therefore,the peak value of aerodynamic moment coefficient amplitude and the sharp ascent process of phase occurs at higher Mach number,which leads to the delay in the occurrence of the transonic dip.Besides,before the transonic dip of airfoil without SDR occurs,the aerodynamic moment phase of airfoil with the SDR decreases slowly due to the decrease in the speed of shock wave moving downstream.This results in an increased flutter speed when employing the SDR before the transonic dip of airfoil without SDR occurs.Meanwhile,the effects of asymmetric split angles on the transonic flutter characteristics are also investigated.Before the transonic dip of airfoil without SDR occurs,the flutter characteristic is dominated by the smaller split angle.
基金the Beijing Natural Science Foundation(Z240029)the National Natural Science Foundation of China(22472004)+2 种基金China National Petroleum Corporation-Peking University Strategic Cooperation Project of Fundamental Researchthe New Cornerstone Science Foundationsupport from the Tencent Foundation through the Xplorer Prize.
文摘Polyvinyl chloride(PVC)is one of the most widely used plastic materials worldwide,particularly in long-life applications such as construction materials.However,recycling options for PVC waste remain limited,as conventional methods often degrade material quality or generate environmentally hazardous byproducts.In this study,we demonstrate an efficient process to convert PVC into new polymers with variable aromatic groups,using triethylsilane as the reductant in different solvents.This approach enables the production of polymers analogous to functionalized polyethylene(PE),which are typically challenging to obtain through conventional copolymerization or direct post-modification of C-H bonds in PE.The resulting polymers exhibit tunable thermal and mechanical properties depending on the introduced aromatic groups,which not only enhance the sustainable valorization of PVC waste,but also provide an opportunity for the synthesis of new functionalized polymers.
基金co-supported by the National Natural Science Foundation of China(Nos.52472394,52425211,52201327,52272360)。
文摘Stall flutter poses great challenges to flight safety.To alleviate this problem,a steady blowing control considering the perturbation and wake-induced vibration at a large angle of attack is developed in this paper,where two blowings are configured on upper and lower tail surfaces to suppress the stall flutter.The stall flutter with one-degree-of-freedom is first evaluated by numerical simulation.The equation of motion for stall flutter is solved by the Newmark-β method.Then,the stall flutter responses for five blowing speeds,i.e.,0,4,12,20,and 28 m/s under the airspeed range of 3–9 m/s,are studied in detail.The stall flutter suppression mechanism can be summarized as follows:a large blowing speed can inject energy into the boundary layer and enhance the high-pressure zone,which delays the flow separation on the suction surface.In this way,the formation of the leading-edge separation vortex is suppressed.Thus,the dynamic stall vortex is weakened and accelerates shedding.In addition,the driving moment is reduced,which leads to a decrement in the stall flutter amplitude.When the blowing speed is 28 m/s(stall flutter amplitude=0.1357 rad),compared with uncontrolled case(stall flutter amplitude=0.6002 rad),the amplitude can decrease by 77.39%,which demonstrates the effectiveness of the proposed steady blowing based active control strategy.
基金sponsored by the National Natural Science Foundation of China(Grant No.32373187)the Research Fund for International Scientists of the National Natural Science Foundation of China(Grant No.32350410404)the Natural Science Foundation of Shanghai(Grant No.23ZR1427000).
文摘This study experimentally investigates the hydrodynamic characteristics,geometric configurations,fluttering motions of the codend,and the instantaneous flow fields inside and around the codend,with and without a liner,under varying catch sizes and inflow velocities.A proper orthogonal decomposition method is employed to extract phase-averaged mean properties of unsteady turbulent flows from flow measurement data obtained using an electromagnetic current velocity meter inside and around the codend.The results reveal that as catch size increases,the drag force,codend motion,Reynolds number,and codend volume increase while the drag coefficient decreases.Owing to the codend shape and pronounced motion,a complex fluid–structure interaction occurs,demonstrating a strong correlation between drag force and codend volume.The oscillation amplitudes of the hydrodynamic forces and codend motions increase with increasing catch size,and their oscillations mainly involve low-frequency activity.A significant reduction in the flow field occurs inside and around the unlined codend without a catch.The flow field is 5.81%,14.39%,and 27.01%lower than the unlined codend with a catch,the codend with a liner but without a catch,and the codend with both a liner and a catch,respectively.Fourier analysis reveals that the codend motions and hydrodynamic forces are mainly characterized by low-frequency activity and are synchronized with the unsteady turbulent flow street.Furthermore,the proper orthogonal decomposition results reveal the development of unsteady turbulent flow inside and around the codend,driven by flow passage blockage caused by the presence of the liner,intense codend motions,and the catch.Understanding the hydrodynamic characteristics and flow instabilities inside and around the codend,particularly those associated with its fluttering motions,is crucial for optimizing trawl design and improving trawl selectivity.
基金supported by the Na⁃tional Science and Technology Major Project(No.Y2019-Ⅰ⁃0018-0017)the National Natural Science Foundation of China(No.U24A2051)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20232037)the Foundation of Key Laboratory of Aero-engine Thermal Environment and Structure,Ministry of Industry and Information Technology(No.CEPE2024002)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KY⁃CX24_0605)。
文摘Advanced propulsion systems experience critical challenges under extreme service conditions,including aerodynamic loads and thermal loads.Especially,flutter stability is a key bottleneck restricting the design and safe op⁃eration of hot structures in advanced propulsion systems employing ceramic matrix composites(CMCs).Compared to traditional nickel-based alloys,CMCs offer superior high-temperature resistance and specific strength,making them ideal for next-generation engine hot structures.The inherent anisotropy,heterogeneity,and complex nonlinear behav⁃ior of CMCs,coupled with extreme operating environments,result in strong multi-physics interactions,including aero-thermo-structural,thermo-mechanical,and damage-aeroelastic coupling.These complexities significantly com⁃plicate vibration stability and flutter analysis.The recent research progresses on these problems are systematically ex⁃amined,focusing on multi-field coupling mechanisms,material constitutive and damage evolution models,multi-scale modeling methods,coupled solution strategies,and the influence of key parameters on flutter characteristics.The current challenges are highlighted,including the complexity of high-temperature nonlinear modeling,the effi⁃ciency of multi-field coupling calculations,and the multi-scale modeling of complex weaving structures.Finally,an outlook on future development directions is presented to provide theoretical support for the design and safety assess⁃ment of hot structures of advanced CMCs.
