The two-dimensional grating serves as a critical component in plane grating interferometers for achieving high-precision multidimensional displacement measurements.The calibration of grating groove density and orthogo...The two-dimensional grating serves as a critical component in plane grating interferometers for achieving high-precision multidimensional displacement measurements.The calibration of grating groove density and orthogonality error of grating grooves not only improves the positioning accuracy of grating interferometers but also provides essential feedback for optimizing two-dimensional grating fabrication.This study proposes a method for simultaneous calibration of these parameters using orthogonal heterodyne laser interferometry.A two-dimensional grating interferometer is built with the grating to be measured,and a biaxial laser interferometer provides a displacement reference for it.The phase mapping relationship between grating interference and laser interference is established.The interference phase information obtained by any two displacements can simultaneously solve the above three parameters and obtain the grating installation error.The feasibility of the proposed method is verified by using a 1200 gr/mm two-dimensional grating.The standard deviation of the grating groove density in the X and Y directions is 0.012 gr/mm and 0.014 gr/mm,respectively.The standard deviation of the orthogonality error of grating grooves is 0.004°,and the standard deviation of the installation error is 0.002°.Compared with the atomic force microscope method,the consistency of the grating groove density in the X and Y directions is better than 0.03 gr/mm and 0.06 gr/mm,and the orthogonality error of grating grooves is better than 0.008°.The experimental results show that the proposed method can be simply and efficiently applied to the calibration of the grating line parameters of the two-dimensional grating.展开更多
As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and el...As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and electrochemical characteristics,MXenes have shown great potential in brain-inspired neuromorphic computing electronics,including neuromorphic gas sensors,pressure sensors and photodetectors.This paper provides a forward-looking review of the research progress regarding MXenes in the neuromorphic sensing domain and discussed the critical challenges that need to be resolved.Key bottlenecks such as insufficient long-term stability under environmental exposure,high costs,scalability limitations in large-scale production,and mechanical mismatch in wearable integration hinder their practical deployment.Furthermore,unresolved issues like interfacial compatibility in heterostructures and energy inefficiency in neu-romorphic signal conversion demand urgent attention.The review offers insights into future research directions enhance the fundamental understanding of MXene properties and promote further integration into neuromorphic computing applications through the convergence with various emerging technologies.展开更多
Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of a...Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of available material systems,making the identification of novel 2D multilayer kagome candidates particularly important.In this work,three types of 2D materials with trilayer kagome lattices,namely Sc_(6)S_(5)X_(6)(X=Cl,Br,I),are predicted based on first-principles calculations.These 2D materials feature two kagome lattices composed of Sc atoms and one kagome lattice composed of S atoms.Stability analysis indicates that these materials can exist as free-standing 2D materials.Electronic structure calculations reveal that Sc_(6)S_(5)X_(6)are narrow-bandgap semiconductors(0.76–0.95 e V),with their band structures exhibiting flat bands contributed by Sc-based kagome lattices and Dirac band gaps resulting from symmetry breaking.The sulfur-based kagome lattice in the central layer contributes an independent flat band below the Fermi level.Additionally,Sc_(6)S_(5)X_(6)exhibit high carrier mobility,with hole and electron mobilities reaching up to 10^(3)cm^(2)·V^(-1)·s^(-1),indicating potential applications in low-dimensional electronic devices.This work provides an excellent example for the development of novel multilayer 2D kagome materials.展开更多
High Speed on/off Valve(HSV)is an essential component in Aerospace Digital Hydraulic Systems(ADHS),which impose stringent requirements on the dynamic performance and reliability of HSV due to the extreme application e...High Speed on/off Valve(HSV)is an essential component in Aerospace Digital Hydraulic Systems(ADHS),which impose stringent requirements on the dynamic performance and reliability of HSV due to the extreme application environments.However,the faster dynamic leads to increased impact between the spool and valve body,causing severe vibration and wear,which creates a conflict between rapid dynamic and high reliability.To address this problem,a Pre-Excitation Soft Switching Control(PESSC)with both pre-excitation and reverse deceleration functionalities is proposed.The initial current is optimized through pre-excitation to accelerate the opening time,while the application of reverse voltage hastens the decline of electromagnetic force,thereby reducing the spool velocity.The PESSC simultaneously achieves both faster dynamic performance and smaller impact velocity.Moreover,the optimal deceleration voltage parameters are obtained through multi-objective optimization.Experimental results demonstrate that the optimized PESSC shortens the opening time from 2.22 ms to 1.65 ms,reduces the impact velocity by 58.3%,and lowers wear by 55.4%.These findings underline the huge potential of PESSC in enhancing the dynamic performance and reliability of HSVs,offering promising applications in aerospace.展开更多
Background The effective orifice area(EOA)is utilized to characterize the hemodynamic performance of the transcatheter heart valve(THV).However,there is no consensus on EOA measurement of self-expanding THV.We aimed t...Background The effective orifice area(EOA)is utilized to characterize the hemodynamic performance of the transcatheter heart valve(THV).However,there is no consensus on EOA measurement of self-expanding THV.We aimed to compare two echocardiographic methods for EOA measurement following transcatheter self-expanding aortic valve implantation.Methods EOA was calculated according to the continuity equation.Two methods were constructed.In Method 1 and Method 2,the left ventricular outflow tract diameter(LVOTd)was measured at the entry of the prosthesis(from trailing-to-leading edge)and proximal to the prosthetic valve leaflets(from trailing-toleading edge),respectively.The velocity-time integral(VTI)of the LVOT(VTILVOT)was recorded by pulsed-wave Doppler(PW)from apical windows.The region of the PW sampling should match that of the LVOTd measurement with precise localization.The mean transvalvular pressure gradient(MG)and VTI of THV was measured by Continuous wave Doppler.Results A total of 113 consecutive patients were recruited.The mean age was 77.2±5.5 years,and 72 patients(63.7%)were male.EOA1 with the use of Method 1 was larger than EOA2(1.56±0.39 cm2 vs.1.48±0.41 cm2,P=0.001).MG correlated better with the indexed EOA1(EOAI1)(r=-0.701,P<0.001)than EOAI2(r=-0.645,P<0.001).According to EOAI(EOAI≤0.65 cm2/m2,respectively),the proportion of sever prosthesis-patient mismatch with the use of EOA1 was lower than EOA2(12.4%vs.21.2%,P<0.05).Compared with EOA2,EOA1 had lower interobserver and intra-observer variability(intra:0.5%±17%vs.3.8%±22%,P<0.001;inter:1.0%±9%vs.3.5%±11%,P<0.001).Conclusions For transcatheter self-expanding valve EOA measurement,LVOTd should be measured in the entry of the prosthesis stent(from trailing-to-leading edge),and VTILVOT should match that of the LVOTd measurement with precise localization.展开更多
A functional interlayer based on two-dimensional(2D)porous modified vermiculite nanosheets(PVS)was obtained by acid-etching vermiculite nanosheets.The as-obtained 2D porous nanosheets exhibited a high specific surface...A functional interlayer based on two-dimensional(2D)porous modified vermiculite nanosheets(PVS)was obtained by acid-etching vermiculite nanosheets.The as-obtained 2D porous nanosheets exhibited a high specific surface area of 427 m^(2)·g^(-1)and rich surface active sites,which help restrain polysulfides(LiPSs)through good physi-cal and chemical adsorption,while simultaneously accelerating the nucleation and dissolution kinetics of Li_(2)S,effec-tively suppressing the shuttle effect.The assembled lithium-sulfur batteries(LSBs)employing the PVS-based inter-layer delivered a high initial discharge capacity of 1386 mAh·g^(-1)at 0.1C(167.5 mAh·g^(-1)),long-term cycling stabil-ity,and good rate property.展开更多
A high-temperature and high-pressure valve is the key equipment of a wind tunnel system;it controls the generation of high-temperature and high-pressure gas.To reduce the adverse impact of high-temperature and high-pr...A high-temperature and high-pressure valve is the key equipment of a wind tunnel system;it controls the generation of high-temperature and high-pressure gas.To reduce the adverse impact of high-temperature and high-pressure gas on the strength of the valve body,a cooling structure is set on the valve seat.This can significantly reduce the temperature of the valve body and valve seat.The effects of its structure on the cooling characteristics and stress of the valve seat are studied,and six main parameters that can completely describe the geometry of the cooling structure are proposed.The central composite design method is used to select sample points,and the multi-objective genetic algorithm(MOGA)method is used for optimal structural design.A modification method according to the main parameters for the valve seat is proposed.The results show that the cooling structure weakens the pressure-bearing capability of the valve seat.Among the six main parameters of the valve seat,the distance from the end face of the lower hole to the Z-axis and the distance from the axis of the lower hole to the origin of the coordinates have the most obvious effects on the average stress of the valve seat.An optimum design value is proposed.This work can provide a reference for the design of high-temperature and high-pressure valves.展开更多
BACKGROUND The management of severe symptomatic aortic stenosis has been revolutionized by transcatheter aortic valve replacement(TAVR),offering a minimally invasive alternative to surgical aortic valve replacement(SA...BACKGROUND The management of severe symptomatic aortic stenosis has been revolutionized by transcatheter aortic valve replacement(TAVR),offering a minimally invasive alternative to surgical aortic valve replacement(SAVR).However,the compara-tive safety and efficacy of these interventions remain subjects of ongoing investigation.AIM To compare the clinical outcomes and safety of TAVR vs SAVR in patients with severe symptomatic aortic stenosis.METHODS A systematic review and meta-analysis were conducted according to PRISMA guidelines.Randomized controlled trials(RCTs)comparing TAVR and SAVR were identified from databases including PubMed,Scopus,and Web of Science up to May 31,2024.Data were extracted on clinical outcomes,including mortality,procedural compli-cations,and post-procedure adverse events.Risk ratios(RRs)with 95%CIs were calculated using a random-effects model.RESULTS A total of 10 RCTs were included.TAVR demonstrated a significantly lower risk of acute kidney injury(RR:0.33;95%CI:0.25–0.44),major bleeding(RR:0.37;95%CI:0.30–0.46),and new-onset atrial fibrillation(RR:0.44;95%CI:0.34–0.57)compared to SAVR.However,TAVR was associated with higher risks of new permanent pacemaker implantation(RR:3.49;95%CI:2.77–4.39),major vascular complications(RR:2.47;95%CI:1.91–3.21),and paraval-vular leaks(RR:4.15;95%CI:3.14–5.48).Mortality at 30 days was comparable(RR:0.95;95%CI:0.78–1.15),but long-term mortality was slightly higher with TAVR in some analyses(RR:1.23;95%CI:1.01–1.49).Rates of stroke(RR:0.97;95%CI:0.81–1.17)and myocardial infarction(RR:0.91;95%CI:0.67–1.24)were similar between the groups.CONCLUSION TAVR offers a less invasive option with significant benefits in reducing acute kidney injury,major bleeding,and new-onset atrial fibrillation,making it particularly advantageous for high-risk surgical candidates.However,higher risks of permanent pacemaker implantation,vascular complications,and paravalvular leaks highlight the need for individualized patient selection and shared decision-making to optimize outcomes.展开更多
BACKGROUND Valvular heart disease affects more than 100 million people worldwide and is associated with significant morbidity and mortality.The prevalence of at least moderate valvular heart disease is 2.5%across all ...BACKGROUND Valvular heart disease affects more than 100 million people worldwide and is associated with significant morbidity and mortality.The prevalence of at least moderate valvular heart disease is 2.5%across all age groups,but its prevalence increases with age.Mitral regurgitation and aortic stenosis are the most frequent types of valvular heart disease in the community and hospital context,res-pectively.Surgical valve replacement(or mitral valve repair)is the standard of care for treating heart valve disease.However,the replacement of a prosthetic heart valve can lead to complications,either in the peri-procedural phase or in the long-term follow-up period.CASE SUMMARY We present a case of a 71-year-old female patient with a history of mitral valve replacement and warfarin anti-coagulation therapy.She was admitted to the intensive care unit due to spontaneously reperfused ischemic stroke of probable cardioembolic etiology.A dysfunctional mitral prosthesis was identified due to malfunction of one of the fixed discs.Furthermore,a possible microthrombotic lesion was suspected.Therefore,systemic thrombolysis was performed with subsequent normalization of mitral disc opening and closing.CONCLUSION This case underscores the critical importance of a multidisciplinary approach for timely decision-making in critically ill patients with prosthetic valve complications.展开更多
Background There is scarce data about comparisons between geriatric assessment tools in patients with aortic stenosis(AS).We aimed to describe the geriatric profile of patients with AS undergoing transcatheter aortic ...Background There is scarce data about comparisons between geriatric assessment tools in patients with aortic stenosis(AS).We aimed to describe the geriatric profile of patients with AS undergoing transcatheter aortic valve implantation(TAVI)and to analyze the ability of different tools for predicting clinical outcomes in this context.Methods This was a single center retrospective registry including patients with AS undergoing TAVI and surviving to hospital discharge.The primary endpoint was all-cause mortality or need for urgent readmission one year after TAVI.Results A total of 377 patients were included(mean age of 80.4 years).Most patients were independent or mildly dependent,with an optimal cognitive status.The proportion of frailty ranged from 17.6%to 49.8%.A total of 20 patients(5.3%)died and 110/377 patients(29.2%)died or were readmitted during follow up.Overall,most components of the geriatric assessment showed an association with clinical outcomes.Disability for instrumental activities showed a significant association with mortality and a strong association with the rate of mortality or readmission.The association between frailty and clinical outcomes was higher for short physical performance battery(SPPB),essential frailty toolset(EFT)and the frailty index based on comprehensive geriatric assessment(IF-VIG)and lower for Fried criteria and FRAIL scale.Conclusions AS patients from this series presented a good physical performance,optimal cognitive status and a reasonably low prevalence of frailty.The best predictive ability was observed for disability for instrumental activities and frailty as measured by the EFT,SPPB and the IF-VIG.展开更多
The proliferation of wearable biodevices has boosted the development of soft,innovative,and multifunctional materials for human health monitoring.The integration of wearable sensors with intelligent systems is an over...The proliferation of wearable biodevices has boosted the development of soft,innovative,and multifunctional materials for human health monitoring.The integration of wearable sensors with intelligent systems is an overwhelming tendency,providing powerful tools for remote health monitoring and personal health management.Among many candidates,two-dimensional(2D)materials stand out due to several exotic mechanical,electrical,optical,and chemical properties that can be efficiently integrated into atomic-thin films.While previous reviews on 2D materials for biodevices primarily focus on conventional configurations and materials like graphene,the rapid development of new 2D materials with exotic properties has opened up novel applications,particularly in smart interaction and integrated functionalities.This review aims to consolidate recent progress,highlight the unique advantages of 2D materials,and guide future research by discussing existing challenges and opportunities in applying 2D materials for smart wearable biodevices.We begin with an in-depth analysis of the advantages,sensing mechanisms,and potential applications of 2D materials in wearable biodevice fabrication.Following this,we systematically discuss state-of-the-art biodevices based on 2D materials for monitoring various physiological signals within the human body.Special attention is given to showcasing the integration of multi-functionality in 2D smart devices,mainly including self-power supply,integrated diagnosis/treatment,and human–machine interaction.Finally,the review concludes with a concise summary of existing challenges and prospective solutions concerning the utilization of2D materials for advanced biodevices.展开更多
Pump valve pipeline vibration brings serious safety hazards to the operation of the equipment,for the pump valve system in the process of variable flow,variable speed,variable openings lead to excessive pipeline vibra...Pump valve pipeline vibration brings serious safety hazards to the operation of the equipment,for the pump valve system in the process of variable flow,variable speed,variable openings lead to excessive pipeline vibration.An active damping device(ADD)is used to the vibration of the pump valve pipeline system to apply the control force,to achieve the active control of the pipeline vibration.A pump-valve pipeline vibration test bench was built to compare the control effect of active damping device on pipeline vibration under different pump valve working conditions,and the results show that applying ADD control could effectively suppress the vibration of the pump valve pipeline and enhance the stability of the equipment during operation.At different pump operating rotation frequencies,the vibration amplitude of the pump valve pipeline in working frequency and its multiple frequencies are also effectively suppressed,with the maximum amplitude reduction of more than 60%.For the valve vibration caused by different operating openings,the vibration of the highest reduction of 68%,and the centrifugal pump drive shaft vi-bration reduced by up to 73%,which provides a new idea for vibration control of pump valve pipeline system.展开更多
The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface...The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface transfer doping,surface electron acceptor materials with high electron affinity(EA)are required to produce a high density of two-dimensional hole gas(2DHG)on the H-diamond subsurface.We have established ingenious theoretical models to demonstrate that even if these solid materials do not have a high EA value,they remain capable of absorbing electrons from the H-diamond surface by forming a negatively charged interface to act as a surface electron acceptor in the surface transfer doping model.Our calculations,particularly for the local density of states,provide compelling evidence that the effect of an interface with negative charges induces an upward band bending on the H-diamond side.Furthermore,the valence band maximum of the diamond atoms at the interface crosses the Fermi level,giving rise to strong surface transfer p-type doping.These results give a strong theoretical interpretation of the origin of 2DHG on H-diamond surfaces.The proposed guidelines contribute to further improvements in the performance of 2DHG H-diamond field effect transistors.展开更多
Gifford-McMahon-type pulse-tube cryocoolers(GM-PTCs)working at liquid helium temperatures are promising in quantum technology and cryogenic physics for their high reliability and minimal vibration.These features stem ...Gifford-McMahon-type pulse-tube cryocoolers(GM-PTCs)working at liquid helium temperatures are promising in quantum technology and cryogenic physics for their high reliability and minimal vibration.These features stem from the fact that there are no extra moving parts introduced into the system.The rotary valve is a key component in GM-PTCs that transfers the output exergy from the compressor to the cold head.Because a low Carnot efficiency of 1.58%is achieved at liquid helium temperatures,optimizing the rotary valve is crucial for improving the efficiency of GM-PTCs.In this regard,an exergy-loss analysis method is proposed in this paper to quantitatively obtain the leakage loss and viscosity loss of a rotary valve by experimental measurements.The results show that viscosity loss accounts for more than 97.5%of the total exergy loss in the rotary valve,and that it is possible to improve the structure of the rotary valve by expanding the flow area by 1.5 times.To verify the method,the cooling temperature and power of a remote two-stage GM-PTC were monitored,with original or optimized rotary valves installed.The experimental results show that compared to the original rotary valve,the optimized rotary valve can improve the cooling efficiency of a GM-PTC by 16.4%,with a cooling power of 0.78 W at 4.2 K.展开更多
Bicuspid aortic valve (BAV) is a common congenital heart valve disease, often accompanied by aortic valve stenosis or regurgitation, infective endocarditis, and aortic diseases such as aortic dilation and dissection. ...Bicuspid aortic valve (BAV) is a common congenital heart valve disease, often accompanied by aortic valve stenosis or regurgitation, infective endocarditis, and aortic diseases such as aortic dilation and dissection. This article aims to review the definition, pathogenesis and genetic basis, classification methods, clinical features and current status of research and treatment and prognosis of BAV, and provide reference for the diagnosis and treatment of BAV. The content and structure of this article are as follows: The first part introduces the definition of BAV;The second part introduces the etiology and classification methods of BAV;The third part briefly describes the clinical manifestations and diagnosis of BAV;The fourth part discusses the treatment strategies and prognosis prediction of BAV;Finally, the article summarizes and looks forward to the future research directions.展开更多
This paper investigates ruin,capital injection,and dividends for a two-dimensional risk model.The model posits that surplus levels of insurance companies are governed by a perturbed composite Poisson risk model.This m...This paper investigates ruin,capital injection,and dividends for a two-dimensional risk model.The model posits that surplus levels of insurance companies are governed by a perturbed composite Poisson risk model.This model introduces a dependence between the two surplus levels,present in both the associated perturbations and the claims resulting from common shocks.Critical levels of capital injection and dividends are established for each of the two risks.The surplus levels are observed discretely at fixed intervals,guiding decisions on capital injection,dividends,and ruin at these junctures.This study employs a two-dimensional Fourier cosine series expansion method to approximate the finite time expected discounted operating cost until ruin.The ensuing approximation error is also quantified.The validity and accuracy of the method are corroborated through numerical examples.Furthermore,the research delves into the optimal capital allocation problem.展开更多
Pediatric heart valve replacement(PHVR)remains a challenging procedure due to the uniqueanatomical and physiological characteristics of children,including growth and development,as well asthe long-term need for durabl...Pediatric heart valve replacement(PHVR)remains a challenging procedure due to the uniqueanatomical and physiological characteristics of children,including growth and development,as well asthe long-term need for durable valve function.This review provides an overview of both surgical andtranscatheter options for aortic,mitral,pulmonary,and tricuspid valve replacements in pediatric patients,highlighting the indications,outcomes,and advancements in technology and technique.Surgical valvereplacement traditionally involves the implantation of biological or mechanical prosthetic valves,withbiologicalvalves beingpreferred in children to reduce the need for lifelong anticoagulation therapy.However,the limitation ofbiological prostheses,nanely their inability to grow with the child,necessitates the frequentneed for reoperations.Recent innovations in valve engineering,such as the development of tissue engineeredand expandable valves,aim to address these issues.Transcatheter valve replacement(TVR)has emergedas a promising alternative,particularly for patients with complex anatomy or those who are high-risk fortraditional surgery.While the use of transcatheter devices in children remains limited due to the smallervascular size and limited long-termn data,several studies have demonstrated the feasibility and safety ofthe procedure in certain patient populations.Despite these advancements,challenges related to valvesize,durability,and the need for individualized treatment planning persist.The future of pediatric heartvalve replacemnent will likely involve a multidisciplinary approach combining surgical,transcatheter,andregenerative medicine strategies,aimed at optimizing outcomes,reducing the need for reinterventions,andimproving long-term quality of life for pediatric patients with valvularheart disease.This article discussesall options availab le for patients with valvular dysfunction,making it easy for parents/patients to go to as areference source of information.展开更多
Valvular Heart Disease(VHD),including stenosis and regurgitation,is a significant contributor to global cardiovascular morbidity.Current prosthetic solutions mechanical and bioprosthetic heart valves each present majo...Valvular Heart Disease(VHD),including stenosis and regurgitation,is a significant contributor to global cardiovascular morbidity.Current prosthetic solutions mechanical and bioprosthetic heart valves each present major limitation.Mechanical valves require lifelong anticoagulation due to thrombogenicity,while bioprosthetic valves suffer from structural degeneration and limited durability.Polymeric Heart Valves(PHVs)have emerged as promising alternatives,aiming to integrate the mechanical resilience of synthetic materials with the biocompatibility and hemodynamic performance of natural valves.Recent studies have explored advanced polymers such as Polyhedral Oligomeric Silsesquioxane–Polycarbonate–Urea–Urethane(POSS-PCU),Silicone–Polyurethane Urea(SiPUU),and nanocomposites like Polyvinyl Alcohol(PVA)and SIBS for their enhanced thromboresistance,calcification resistance,and long-term mechanical durability.Complementary to material innovation,fabrication methods such as 3D printing,Melt Electrospinning Writing(MEW),and Focused Rotary Jet Spinning(FRJS)offer patient-specific designs and microstructural control.This review systematically compares traditional and next-generation prostheses,examines mechanical and biological performance,and discusses critical design challenges including porosity,thrombogenicity,and leaflet calcification.Finite Element Analysis(FEA)and Computational Fluid Dynamics(CFD)are highlighted for optimizing design and simulating physiological conditions.By presenting recent preclinical progress and manufacturing strategies,this review outlines a translational roadmap toward clinically viable,biomimetic polymeric heart valves capable of addressing the needs of both adult and pediatric patients.Compared to traditional bioprosthetic tissues,advanced polymers offer better resistance to calcification,reduced thrombogenicity,and tunable mechanical properties.展开更多
文摘The two-dimensional grating serves as a critical component in plane grating interferometers for achieving high-precision multidimensional displacement measurements.The calibration of grating groove density and orthogonality error of grating grooves not only improves the positioning accuracy of grating interferometers but also provides essential feedback for optimizing two-dimensional grating fabrication.This study proposes a method for simultaneous calibration of these parameters using orthogonal heterodyne laser interferometry.A two-dimensional grating interferometer is built with the grating to be measured,and a biaxial laser interferometer provides a displacement reference for it.The phase mapping relationship between grating interference and laser interference is established.The interference phase information obtained by any two displacements can simultaneously solve the above three parameters and obtain the grating installation error.The feasibility of the proposed method is verified by using a 1200 gr/mm two-dimensional grating.The standard deviation of the grating groove density in the X and Y directions is 0.012 gr/mm and 0.014 gr/mm,respectively.The standard deviation of the orthogonality error of grating grooves is 0.004°,and the standard deviation of the installation error is 0.002°.Compared with the atomic force microscope method,the consistency of the grating groove density in the X and Y directions is better than 0.03 gr/mm and 0.06 gr/mm,and the orthogonality error of grating grooves is better than 0.008°.The experimental results show that the proposed method can be simply and efficiently applied to the calibration of the grating line parameters of the two-dimensional grating.
基金supported by the NSFC(12474071)Natural Science Foundation of Shandong Province(ZR2024YQ051,ZR2025QB50)+6 种基金Guangdong Basic and Applied Basic Research Foundation(2025A1515011191)the Shanghai Sailing Program(23YF1402200,23YF1402400)funded by Basic Research Program of Jiangsu(BK20240424)Open Research Fund of State Key Laboratory of Crystal Materials(KF2406)Taishan Scholar Foundation of Shandong Province(tsqn202408006,tsqn202507058)Young Talent of Lifting engineering for Science and Technology in Shandong,China(SDAST2024QTB002)the Qilu Young Scholar Program of Shandong University。
文摘As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and electrochemical characteristics,MXenes have shown great potential in brain-inspired neuromorphic computing electronics,including neuromorphic gas sensors,pressure sensors and photodetectors.This paper provides a forward-looking review of the research progress regarding MXenes in the neuromorphic sensing domain and discussed the critical challenges that need to be resolved.Key bottlenecks such as insufficient long-term stability under environmental exposure,high costs,scalability limitations in large-scale production,and mechanical mismatch in wearable integration hinder their practical deployment.Furthermore,unresolved issues like interfacial compatibility in heterostructures and energy inefficiency in neu-romorphic signal conversion demand urgent attention.The review offers insights into future research directions enhance the fundamental understanding of MXene properties and promote further integration into neuromorphic computing applications through the convergence with various emerging technologies.
基金supported by the Fundamental Research Funds for the Central Universities(WUT:2024IVA052 and Grant No.104972025KFYjc0089)。
文摘Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of available material systems,making the identification of novel 2D multilayer kagome candidates particularly important.In this work,three types of 2D materials with trilayer kagome lattices,namely Sc_(6)S_(5)X_(6)(X=Cl,Br,I),are predicted based on first-principles calculations.These 2D materials feature two kagome lattices composed of Sc atoms and one kagome lattice composed of S atoms.Stability analysis indicates that these materials can exist as free-standing 2D materials.Electronic structure calculations reveal that Sc_(6)S_(5)X_(6)are narrow-bandgap semiconductors(0.76–0.95 e V),with their band structures exhibiting flat bands contributed by Sc-based kagome lattices and Dirac band gaps resulting from symmetry breaking.The sulfur-based kagome lattice in the central layer contributes an independent flat band below the Fermi level.Additionally,Sc_(6)S_(5)X_(6)exhibit high carrier mobility,with hole and electron mobilities reaching up to 10^(3)cm^(2)·V^(-1)·s^(-1),indicating potential applications in low-dimensional electronic devices.This work provides an excellent example for the development of novel multilayer 2D kagome materials.
基金supported in part by the “Pioneer”and “Leading Goose”R&D Program of Zhejiang Province(Nos.2022C01132 and 2022C01122)the National Natural Science Foundation of China(No.52005441)+3 种基金the Young Elite Scientist Sponsorship Program by CAST(No.20222024QNRC001)the State Key Laboratory of Mechanical System and Vibration,China(No.MSV202316)the Fundamental Research Funds for the Provincial Universities of Zhejiang,China(RF-A2023007)the Research Project of ZJUT,China(No.GYY-ZH-2023075)。
文摘High Speed on/off Valve(HSV)is an essential component in Aerospace Digital Hydraulic Systems(ADHS),which impose stringent requirements on the dynamic performance and reliability of HSV due to the extreme application environments.However,the faster dynamic leads to increased impact between the spool and valve body,causing severe vibration and wear,which creates a conflict between rapid dynamic and high reliability.To address this problem,a Pre-Excitation Soft Switching Control(PESSC)with both pre-excitation and reverse deceleration functionalities is proposed.The initial current is optimized through pre-excitation to accelerate the opening time,while the application of reverse voltage hastens the decline of electromagnetic force,thereby reducing the spool velocity.The PESSC simultaneously achieves both faster dynamic performance and smaller impact velocity.Moreover,the optimal deceleration voltage parameters are obtained through multi-objective optimization.Experimental results demonstrate that the optimized PESSC shortens the opening time from 2.22 ms to 1.65 ms,reduces the impact velocity by 58.3%,and lowers wear by 55.4%.These findings underline the huge potential of PESSC in enhancing the dynamic performance and reliability of HSVs,offering promising applications in aerospace.
文摘Background The effective orifice area(EOA)is utilized to characterize the hemodynamic performance of the transcatheter heart valve(THV).However,there is no consensus on EOA measurement of self-expanding THV.We aimed to compare two echocardiographic methods for EOA measurement following transcatheter self-expanding aortic valve implantation.Methods EOA was calculated according to the continuity equation.Two methods were constructed.In Method 1 and Method 2,the left ventricular outflow tract diameter(LVOTd)was measured at the entry of the prosthesis(from trailing-to-leading edge)and proximal to the prosthetic valve leaflets(from trailing-toleading edge),respectively.The velocity-time integral(VTI)of the LVOT(VTILVOT)was recorded by pulsed-wave Doppler(PW)from apical windows.The region of the PW sampling should match that of the LVOTd measurement with precise localization.The mean transvalvular pressure gradient(MG)and VTI of THV was measured by Continuous wave Doppler.Results A total of 113 consecutive patients were recruited.The mean age was 77.2±5.5 years,and 72 patients(63.7%)were male.EOA1 with the use of Method 1 was larger than EOA2(1.56±0.39 cm2 vs.1.48±0.41 cm2,P=0.001).MG correlated better with the indexed EOA1(EOAI1)(r=-0.701,P<0.001)than EOAI2(r=-0.645,P<0.001).According to EOAI(EOAI≤0.65 cm2/m2,respectively),the proportion of sever prosthesis-patient mismatch with the use of EOA1 was lower than EOA2(12.4%vs.21.2%,P<0.05).Compared with EOA2,EOA1 had lower interobserver and intra-observer variability(intra:0.5%±17%vs.3.8%±22%,P<0.001;inter:1.0%±9%vs.3.5%±11%,P<0.001).Conclusions For transcatheter self-expanding valve EOA measurement,LVOTd should be measured in the entry of the prosthesis stent(from trailing-to-leading edge),and VTILVOT should match that of the LVOTd measurement with precise localization.
文摘A functional interlayer based on two-dimensional(2D)porous modified vermiculite nanosheets(PVS)was obtained by acid-etching vermiculite nanosheets.The as-obtained 2D porous nanosheets exhibited a high specific surface area of 427 m^(2)·g^(-1)and rich surface active sites,which help restrain polysulfides(LiPSs)through good physi-cal and chemical adsorption,while simultaneously accelerating the nucleation and dissolution kinetics of Li_(2)S,effec-tively suppressing the shuttle effect.The assembled lithium-sulfur batteries(LSBs)employing the PVS-based inter-layer delivered a high initial discharge capacity of 1386 mAh·g^(-1)at 0.1C(167.5 mAh·g^(-1)),long-term cycling stabil-ity,and good rate property.
基金supported by the National Natural Science Foundation of China(No.52175067)the Zhejiang Key Research&Development Project(No.2021C01021)+1 种基金the Natural Science Foundation of Zhejiang Province(No.LY20E050016)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(CPSF)(No.GZC20241478)。
文摘A high-temperature and high-pressure valve is the key equipment of a wind tunnel system;it controls the generation of high-temperature and high-pressure gas.To reduce the adverse impact of high-temperature and high-pressure gas on the strength of the valve body,a cooling structure is set on the valve seat.This can significantly reduce the temperature of the valve body and valve seat.The effects of its structure on the cooling characteristics and stress of the valve seat are studied,and six main parameters that can completely describe the geometry of the cooling structure are proposed.The central composite design method is used to select sample points,and the multi-objective genetic algorithm(MOGA)method is used for optimal structural design.A modification method according to the main parameters for the valve seat is proposed.The results show that the cooling structure weakens the pressure-bearing capability of the valve seat.Among the six main parameters of the valve seat,the distance from the end face of the lower hole to the Z-axis and the distance from the axis of the lower hole to the origin of the coordinates have the most obvious effects on the average stress of the valve seat.An optimum design value is proposed.This work can provide a reference for the design of high-temperature and high-pressure valves.
文摘BACKGROUND The management of severe symptomatic aortic stenosis has been revolutionized by transcatheter aortic valve replacement(TAVR),offering a minimally invasive alternative to surgical aortic valve replacement(SAVR).However,the compara-tive safety and efficacy of these interventions remain subjects of ongoing investigation.AIM To compare the clinical outcomes and safety of TAVR vs SAVR in patients with severe symptomatic aortic stenosis.METHODS A systematic review and meta-analysis were conducted according to PRISMA guidelines.Randomized controlled trials(RCTs)comparing TAVR and SAVR were identified from databases including PubMed,Scopus,and Web of Science up to May 31,2024.Data were extracted on clinical outcomes,including mortality,procedural compli-cations,and post-procedure adverse events.Risk ratios(RRs)with 95%CIs were calculated using a random-effects model.RESULTS A total of 10 RCTs were included.TAVR demonstrated a significantly lower risk of acute kidney injury(RR:0.33;95%CI:0.25–0.44),major bleeding(RR:0.37;95%CI:0.30–0.46),and new-onset atrial fibrillation(RR:0.44;95%CI:0.34–0.57)compared to SAVR.However,TAVR was associated with higher risks of new permanent pacemaker implantation(RR:3.49;95%CI:2.77–4.39),major vascular complications(RR:2.47;95%CI:1.91–3.21),and paraval-vular leaks(RR:4.15;95%CI:3.14–5.48).Mortality at 30 days was comparable(RR:0.95;95%CI:0.78–1.15),but long-term mortality was slightly higher with TAVR in some analyses(RR:1.23;95%CI:1.01–1.49).Rates of stroke(RR:0.97;95%CI:0.81–1.17)and myocardial infarction(RR:0.91;95%CI:0.67–1.24)were similar between the groups.CONCLUSION TAVR offers a less invasive option with significant benefits in reducing acute kidney injury,major bleeding,and new-onset atrial fibrillation,making it particularly advantageous for high-risk surgical candidates.However,higher risks of permanent pacemaker implantation,vascular complications,and paravalvular leaks highlight the need for individualized patient selection and shared decision-making to optimize outcomes.
文摘BACKGROUND Valvular heart disease affects more than 100 million people worldwide and is associated with significant morbidity and mortality.The prevalence of at least moderate valvular heart disease is 2.5%across all age groups,but its prevalence increases with age.Mitral regurgitation and aortic stenosis are the most frequent types of valvular heart disease in the community and hospital context,res-pectively.Surgical valve replacement(or mitral valve repair)is the standard of care for treating heart valve disease.However,the replacement of a prosthetic heart valve can lead to complications,either in the peri-procedural phase or in the long-term follow-up period.CASE SUMMARY We present a case of a 71-year-old female patient with a history of mitral valve replacement and warfarin anti-coagulation therapy.She was admitted to the intensive care unit due to spontaneously reperfused ischemic stroke of probable cardioembolic etiology.A dysfunctional mitral prosthesis was identified due to malfunction of one of the fixed discs.Furthermore,a possible microthrombotic lesion was suspected.Therefore,systemic thrombolysis was performed with subsequent normalization of mitral disc opening and closing.CONCLUSION This case underscores the critical importance of a multidisciplinary approach for timely decision-making in critically ill patients with prosthetic valve complications.
文摘Background There is scarce data about comparisons between geriatric assessment tools in patients with aortic stenosis(AS).We aimed to describe the geriatric profile of patients with AS undergoing transcatheter aortic valve implantation(TAVI)and to analyze the ability of different tools for predicting clinical outcomes in this context.Methods This was a single center retrospective registry including patients with AS undergoing TAVI and surviving to hospital discharge.The primary endpoint was all-cause mortality or need for urgent readmission one year after TAVI.Results A total of 377 patients were included(mean age of 80.4 years).Most patients were independent or mildly dependent,with an optimal cognitive status.The proportion of frailty ranged from 17.6%to 49.8%.A total of 20 patients(5.3%)died and 110/377 patients(29.2%)died or were readmitted during follow up.Overall,most components of the geriatric assessment showed an association with clinical outcomes.Disability for instrumental activities showed a significant association with mortality and a strong association with the rate of mortality or readmission.The association between frailty and clinical outcomes was higher for short physical performance battery(SPPB),essential frailty toolset(EFT)and the frailty index based on comprehensive geriatric assessment(IF-VIG)and lower for Fried criteria and FRAIL scale.Conclusions AS patients from this series presented a good physical performance,optimal cognitive status and a reasonably low prevalence of frailty.The best predictive ability was observed for disability for instrumental activities and frailty as measured by the EFT,SPPB and the IF-VIG.
基金the support from the National Natural Science Foundation of China(22272004,62272041)the Fundamental Research Funds for the Central Universities(YWF-22-L-1256)+1 种基金the National Key R&D Program of China(2023YFC3402600)the Beijing Institute of Technology Research Fund Program for Young Scholars(No.1870011182126)。
文摘The proliferation of wearable biodevices has boosted the development of soft,innovative,and multifunctional materials for human health monitoring.The integration of wearable sensors with intelligent systems is an overwhelming tendency,providing powerful tools for remote health monitoring and personal health management.Among many candidates,two-dimensional(2D)materials stand out due to several exotic mechanical,electrical,optical,and chemical properties that can be efficiently integrated into atomic-thin films.While previous reviews on 2D materials for biodevices primarily focus on conventional configurations and materials like graphene,the rapid development of new 2D materials with exotic properties has opened up novel applications,particularly in smart interaction and integrated functionalities.This review aims to consolidate recent progress,highlight the unique advantages of 2D materials,and guide future research by discussing existing challenges and opportunities in applying 2D materials for smart wearable biodevices.We begin with an in-depth analysis of the advantages,sensing mechanisms,and potential applications of 2D materials in wearable biodevice fabrication.Following this,we systematically discuss state-of-the-art biodevices based on 2D materials for monitoring various physiological signals within the human body.Special attention is given to showcasing the integration of multi-functionality in 2D smart devices,mainly including self-power supply,integrated diagnosis/treatment,and human–machine interaction.Finally,the review concludes with a concise summary of existing challenges and prospective solutions concerning the utilization of2D materials for advanced biodevices.
基金The Fundamental Research Funds for the Central Universities(JD2423)。
文摘Pump valve pipeline vibration brings serious safety hazards to the operation of the equipment,for the pump valve system in the process of variable flow,variable speed,variable openings lead to excessive pipeline vibration.An active damping device(ADD)is used to the vibration of the pump valve pipeline system to apply the control force,to achieve the active control of the pipeline vibration.A pump-valve pipeline vibration test bench was built to compare the control effect of active damping device on pipeline vibration under different pump valve working conditions,and the results show that applying ADD control could effectively suppress the vibration of the pump valve pipeline and enhance the stability of the equipment during operation.At different pump operating rotation frequencies,the vibration amplitude of the pump valve pipeline in working frequency and its multiple frequencies are also effectively suppressed,with the maximum amplitude reduction of more than 60%.For the valve vibration caused by different operating openings,the vibration of the highest reduction of 68%,and the centrifugal pump drive shaft vi-bration reduced by up to 73%,which provides a new idea for vibration control of pump valve pipeline system.
基金supported by the National Nat-ural Science Foundation of China(Nos.62174122,U2241244,and 52302046)Major Program(JD)of Hubei Province(No.2023BAA008)+2 种基金the Fundamental Research Funds for the Central Universities(Nos.2042023kf0116 and 2042023kf1041)the Guangdong Basic and Applied Basic Research Foundation(Nos.2024A1515011764 and 2024A1515010383)the Open Fund of Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration(Wuhan University)(No.EMPI2023016).
文摘The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface transfer doping,surface electron acceptor materials with high electron affinity(EA)are required to produce a high density of two-dimensional hole gas(2DHG)on the H-diamond subsurface.We have established ingenious theoretical models to demonstrate that even if these solid materials do not have a high EA value,they remain capable of absorbing electrons from the H-diamond surface by forming a negatively charged interface to act as a surface electron acceptor in the surface transfer doping model.Our calculations,particularly for the local density of states,provide compelling evidence that the effect of an interface with negative charges induces an upward band bending on the H-diamond side.Furthermore,the valence band maximum of the diamond atoms at the interface crosses the Fermi level,giving rise to strong surface transfer p-type doping.These results give a strong theoretical interpretation of the origin of 2DHG on H-diamond surfaces.The proposed guidelines contribute to further improvements in the performance of 2DHG H-diamond field effect transistors.
基金supported by the National Key Research&Development Program of China(No.2023YFF0721304)the Key Research&Development Program of Jiangsu Province(No.2021015-4),China。
文摘Gifford-McMahon-type pulse-tube cryocoolers(GM-PTCs)working at liquid helium temperatures are promising in quantum technology and cryogenic physics for their high reliability and minimal vibration.These features stem from the fact that there are no extra moving parts introduced into the system.The rotary valve is a key component in GM-PTCs that transfers the output exergy from the compressor to the cold head.Because a low Carnot efficiency of 1.58%is achieved at liquid helium temperatures,optimizing the rotary valve is crucial for improving the efficiency of GM-PTCs.In this regard,an exergy-loss analysis method is proposed in this paper to quantitatively obtain the leakage loss and viscosity loss of a rotary valve by experimental measurements.The results show that viscosity loss accounts for more than 97.5%of the total exergy loss in the rotary valve,and that it is possible to improve the structure of the rotary valve by expanding the flow area by 1.5 times.To verify the method,the cooling temperature and power of a remote two-stage GM-PTC were monitored,with original or optimized rotary valves installed.The experimental results show that compared to the original rotary valve,the optimized rotary valve can improve the cooling efficiency of a GM-PTC by 16.4%,with a cooling power of 0.78 W at 4.2 K.
文摘Bicuspid aortic valve (BAV) is a common congenital heart valve disease, often accompanied by aortic valve stenosis or regurgitation, infective endocarditis, and aortic diseases such as aortic dilation and dissection. This article aims to review the definition, pathogenesis and genetic basis, classification methods, clinical features and current status of research and treatment and prognosis of BAV, and provide reference for the diagnosis and treatment of BAV. The content and structure of this article are as follows: The first part introduces the definition of BAV;The second part introduces the etiology and classification methods of BAV;The third part briefly describes the clinical manifestations and diagnosis of BAV;The fourth part discusses the treatment strategies and prognosis prediction of BAV;Finally, the article summarizes and looks forward to the future research directions.
基金supported by the Shihezi University High-Level Talents Research Startup Project(Project No.RCZK202521)the National Natural Science Foundation of China(Grant Nos.12271066,11871121,12171405)+1 种基金the Chongqing Natural Science Foundation Joint Fund for Innovation and Development Project(Project No.CSTB2024NSCQLZX0085)the Chongqing Normal University Foundation(Grant No.23XLB018).
文摘This paper investigates ruin,capital injection,and dividends for a two-dimensional risk model.The model posits that surplus levels of insurance companies are governed by a perturbed composite Poisson risk model.This model introduces a dependence between the two surplus levels,present in both the associated perturbations and the claims resulting from common shocks.Critical levels of capital injection and dividends are established for each of the two risks.The surplus levels are observed discretely at fixed intervals,guiding decisions on capital injection,dividends,and ruin at these junctures.This study employs a two-dimensional Fourier cosine series expansion method to approximate the finite time expected discounted operating cost until ruin.The ensuing approximation error is also quantified.The validity and accuracy of the method are corroborated through numerical examples.Furthermore,the research delves into the optimal capital allocation problem.
文摘Pediatric heart valve replacement(PHVR)remains a challenging procedure due to the uniqueanatomical and physiological characteristics of children,including growth and development,as well asthe long-term need for durable valve function.This review provides an overview of both surgical andtranscatheter options for aortic,mitral,pulmonary,and tricuspid valve replacements in pediatric patients,highlighting the indications,outcomes,and advancements in technology and technique.Surgical valvereplacement traditionally involves the implantation of biological or mechanical prosthetic valves,withbiologicalvalves beingpreferred in children to reduce the need for lifelong anticoagulation therapy.However,the limitation ofbiological prostheses,nanely their inability to grow with the child,necessitates the frequentneed for reoperations.Recent innovations in valve engineering,such as the development of tissue engineeredand expandable valves,aim to address these issues.Transcatheter valve replacement(TVR)has emergedas a promising alternative,particularly for patients with complex anatomy or those who are high-risk fortraditional surgery.While the use of transcatheter devices in children remains limited due to the smallervascular size and limited long-termn data,several studies have demonstrated the feasibility and safety ofthe procedure in certain patient populations.Despite these advancements,challenges related to valvesize,durability,and the need for individualized treatment planning persist.The future of pediatric heartvalve replacemnent will likely involve a multidisciplinary approach combining surgical,transcatheter,andregenerative medicine strategies,aimed at optimizing outcomes,reducing the need for reinterventions,andimproving long-term quality of life for pediatric patients with valvularheart disease.This article discussesall options availab le for patients with valvular dysfunction,making it easy for parents/patients to go to as areference source of information.
文摘Valvular Heart Disease(VHD),including stenosis and regurgitation,is a significant contributor to global cardiovascular morbidity.Current prosthetic solutions mechanical and bioprosthetic heart valves each present major limitation.Mechanical valves require lifelong anticoagulation due to thrombogenicity,while bioprosthetic valves suffer from structural degeneration and limited durability.Polymeric Heart Valves(PHVs)have emerged as promising alternatives,aiming to integrate the mechanical resilience of synthetic materials with the biocompatibility and hemodynamic performance of natural valves.Recent studies have explored advanced polymers such as Polyhedral Oligomeric Silsesquioxane–Polycarbonate–Urea–Urethane(POSS-PCU),Silicone–Polyurethane Urea(SiPUU),and nanocomposites like Polyvinyl Alcohol(PVA)and SIBS for their enhanced thromboresistance,calcification resistance,and long-term mechanical durability.Complementary to material innovation,fabrication methods such as 3D printing,Melt Electrospinning Writing(MEW),and Focused Rotary Jet Spinning(FRJS)offer patient-specific designs and microstructural control.This review systematically compares traditional and next-generation prostheses,examines mechanical and biological performance,and discusses critical design challenges including porosity,thrombogenicity,and leaflet calcification.Finite Element Analysis(FEA)and Computational Fluid Dynamics(CFD)are highlighted for optimizing design and simulating physiological conditions.By presenting recent preclinical progress and manufacturing strategies,this review outlines a translational roadmap toward clinically viable,biomimetic polymeric heart valves capable of addressing the needs of both adult and pediatric patients.Compared to traditional bioprosthetic tissues,advanced polymers offer better resistance to calcification,reduced thrombogenicity,and tunable mechanical properties.
