Background: Non-radiographic axial spondyloarthritis is a progressive and disabling inflammatory disease affecting young adults, with limited treatment options. TNFi are more efficacious than JAKi and IL1-7i in nr-ax ...Background: Non-radiographic axial spondyloarthritis is a progressive and disabling inflammatory disease affecting young adults, with limited treatment options. TNFi are more efficacious than JAKi and IL1-7i in nr-ax SPA and it has a well-known safety profile over a longer duration. Recently, many IL-17i and JAKi were approved for the treatment of nr-ax SPA;however, data comparing IL1-7i and JAKi in terms of efficacy and safety is lacking. This systematized review aimed to compare the existing efficacy and safety data of JAKi vs IL-17i in the treatment of patients with nr-ax SPA. Methods: A systematic literature search was performed using relevant keywords in many databases. According to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA, 2020), relevant articles were included and evaluated in this review. Efficacy and safety data were collected, analyzed and compared through week 52. The first check was done by the end of week 14 and week 16 for upadacitinib and IL-17i respectively. Results: Data from four RCTs evaluating upadacitinib, secukinumab, ixekizumab, and bimekizumab comprising 1425 patients were analyzed. Overall, a comparable efficacy and safety profile were observed across different treatment arms through week 52;however, non-significant variations were encountered in some outcome measures. The primary endpoint among these RCTs (ASAS40 response rate) was met and it was higher in patients treated with bimekizumab 160 mg sc Q 4 weeks in TNFi non responders (48%) and lowest in ixekizumab 80 mg sc Q 4 weeks treated patients, (35%) (p Conclusion: The above-mentioned three IL-17i and the only one JAKi demonstrated comparable safety and efficacy profiles with some minor variations. A head-to-head trial comparing the effectiveness and safety characteristics of JAKi vs IL-17i may be needed in patients with active nr-ax SpA.展开更多
Strong multi-kilotesla magnetic fields have various applications in high-energy density science and laboratory astrophysics, but they are not readily available. In our previous work [Y. Shi et al., Phys. Rev. Lett. 13...Strong multi-kilotesla magnetic fields have various applications in high-energy density science and laboratory astrophysics, but they are not readily available. In our previous work [Y. Shi et al., Phys. Rev. Lett. 130, 155101(2023)], we developed a novel approach for generating such fields using multiple conventional laser beams with a twist in the pointing direction. This method is particularly well-suited for multi-kilojoule petawatt-class laser systems like SG-Ⅱ UP, which are designed with multiple linearly polarized beamlets. Utilizing three-dimensional kinetic particle-in-cell simulations, we examine critical factors for a proof-of-principle experiment, such as laser polarization, relative pulse delay,phase offset, pointing stability, and target configuration, and their impact on magnetic field generation. Our general conclusion is that the approach is very robust and can be realized under a wide range of laser parameters and plasma conditions. We also provide an in-depth analysis of the axial magnetic field configuration, azimuthal electron current, and electron and ion orbital angular momentum densities.Supported by a simple model, our analysis shows that the axial magnetic field decays owing to the expansion of hot electrons.展开更多
Objective:To investigate the influence of axial length(AL),corneal curvature(CR),and the ratio of axial length to corneal radius of curvature(AL/CR)on myopia in children,and to evaluate the accuracy and specificity of...Objective:To investigate the influence of axial length(AL),corneal curvature(CR),and the ratio of axial length to corneal radius of curvature(AL/CR)on myopia in children,and to evaluate the accuracy and specificity of AL/CR in diagnosing myopia in children.Methods:A cross-sectional study was conducted.A total of 200 children(400 eyes)aged 6-12 years were recruited from the ophthalmology outpatient clinic of Fuling District People’s Hospital from December 2022 to December 2023.AL,CR,and AL/CR were measured,and comprehensive optometry was performed under cycloplegia,with the results recorded in spherical equivalent(SE)form.Results:A total of 200 subjects(400 eyes)were included in this study,of which 330 eyes(82.50%)were myopic.No significant differences in CR were observed among different refractive groups,while significant differences were noted in SE,AL,and AL/CR.The AL and AL/CR ratios were higher in myopic eyes compared to emmetropic and hyperopic eyes.Using cycloplegia as the gold standard,SE in the myopia group was correlated with AL,AL/CR,and CR,with stronger correlations observed with AL and AL/CR.An AL/CR value>3 demonstrated a sensitivity of 0.918,specificity of 0.786,misdiagnosis rate of 0.214,missed diagnosis rate of 0.082,and accuracy of 89.5%in diagnosing myopia.Conclusion:AL and AL/CR values are highly correlated with SE,with the strongest correlation observed in the myopia group.The AL/CR value exhibits high diagnostic value in determining myopia in children.展开更多
This study focused on the buckling characteristics of egg-shaped shells with single crack and double cracks under axial pressure.First,the geometric parameters of the egg-shaped shell were designed,and a numerical mod...This study focused on the buckling characteristics of egg-shaped shells with single crack and double cracks under axial pressure.First,the geometric parameters of the egg-shaped shell were designed,and a numerical model of the egg-shaped shell was established.Then,the initial crack was introduced into the equatorial weld of the egg-shaped shell,and the effects of the crack on the buckling characteristics under different wall thicknesses were explored,as were the effects of the single crack direction,double crack angle and spacing on the buckling characteristics.Finally,crack-free,single crack and double crack egg-shaped shells were fabricated from Q235 steel.The buckling loads and failure modes of the three egg-shaped shells were obtained via axial compression experiments.The numerical critical buckling loads and buckling modes were compared with the experimental results to verify the accuracy of the numerical model.The results of this study are valuable for the design of egg-shaped shells under axial loading.展开更多
The effects of Reynolds number on the compressor efficiency are investigated by tests on three highlyloaded 10-stage axial compressors.The tests are conducted by adjusting the inlet total pressure,and thus different R...The effects of Reynolds number on the compressor efficiency are investigated by tests on three highlyloaded 10-stage axial compressors.The tests are conducted by adjusting the inlet total pressure,and thus different Reynolds numbers are obtained.The results indicate that the compressor efficiency decreases when the Reynolds number decreases.Based on the test results,reasonable correlations between the Reynolds number and compressor efficiency for each of the three compressors are obtained.The comparison between the test result-deduced correlations and Wassell correlations indicates that the effects of Reynolds number on the efficiency predicted by the Wassell correlations are less than those obtained by the test result-deduced correlations.Owing to the complex loss models and flow behavior in highly-loaded multi-stage compressors,additional influence factors,including the tip clearance and the compressor inlet duct design,should be considered for performance correlations.Nevertheless,the Wassell correlations are valid for the tendency prediction of performance changes relating to the Reynolds number,while accurate correlations still largely depend on the specific test results.展开更多
Steel cylindrical shells are widely used in engineering structures due to their high strength-to-weight ratio,but they are vulnerable to buckling under axial loads.To address this limitation,fiber-reinforced polymer(F...Steel cylindrical shells are widely used in engineering structures due to their high strength-to-weight ratio,but they are vulnerable to buckling under axial loads.To address this limitation,fiber-reinforced polymer(FRP)composites have emerged as promising materials for structural reinforcement.This study investigates the buckling behavior of steel cylindrical shells reinforced with inner and outer layers of polymer composite materials under axial compression.Using analytical and numerical modeling methods,the critical buckling loads for different reinforcement options were evaluated.Two-sided glass fiber reinforced plastic(GFRP)or carbon fiber reinforced plastic(CFRP)coatings,as well as combined coatings with layers of different composites,were considered.GFRP+CFRPIn the calculations,the coatings were treated as homogeneous orthotropic materials with equivalent averaged elastic characteristics.The numerical analysis revealed that CFRP reinforcement achieved the highest increase in buckling load,with improvements ranging from 9.84%to 47.29%,depending on the composite thickness and steel shell thickness.GFRP reinforcement,while beneficial,demonstrated a lower effectiveness,with buckling load increases between 5.89%and 19.30%.The hybrid reinforcement provided an optimal balance,improving buckling resistance by GFRP+CFRP6.94%to 43.95%.Statistical analysis further identified composite type and thickness as the most significant factors affecting buckling performance.The findings suggest that CFRP is the preferred reinforcement material,especially when applied to thin-walled cylindrical shells,while hybrid reinforcements can be effectively utilized for structures requiring a balance between stiffness and ductility.These insights provide a foundation for optimizing FRP reinforcement strategies to enhance the structural integrity of steel shells in engineering applications.展开更多
AIM:To investigate the ocular biological characteristics of children with myopia and rapid axial length(AL)changes prescribed spectacles with highly aspherical lenslets(HAL).METHODS:Data were collected from 156 childr...AIM:To investigate the ocular biological characteristics of children with myopia and rapid axial length(AL)changes prescribed spectacles with highly aspherical lenslets(HAL).METHODS:Data were collected from 156 children(252 eyes)with myopia and HAL treatment who were aged 7-13 and had rapid AL changes.The participants were divided into groups with AL reduction and elongation according to the changes in AL within 6mo.Paired t-tests were used to compare the ocular biological parameters at baseline and after rapid changes post-HAL treatment.Pearson’s correlation analysis was used to determine the association between the ocular parameters and AL changes.RESULTS:The ocular biological parameters significantly changed in the children with myopia and rapid AL changes after HAL treatment.In the group with AL reduction,the anterior chamber depth(ACD)and vitreous chamber depth(VCD)decreased.The crystalline lens thickness(CLT)increased,corneal flat keratometry(FK)decreased,and steep keratometry(SK)increased(all P<0.001).The eyes in the group with AL elongation had increased ACD and VCD and steepened SK,but the CLT or FK findings were not different.AL change was negatively associated with baseline astigmatism(r=-0.171;P=0.007).CONCLUSION:In the eyes with HAL treatment,decreased ACD and VCD,thickened CLT,flattened FK,and steepened SK are observed during AL reduction.Lower baseline astigmatism is associated with AL reduction.The AL reduction may suggest the potential efficacy of HAL intervention in myopia control,while providing evidence for optimizing personalized myopia management strategies.Further longitudinal studies are warranted to validate whether rapid AL changes predict sustained treatment efficacy.展开更多
Moist-electric generation,a green and environmentally friendly energy harvesting technology,is undoubt-edly one of the effective methods to alleviate energy shortages and environmental damage.However,the lack of fiber...Moist-electric generation,a green and environmentally friendly energy harvesting technology,is undoubt-edly one of the effective methods to alleviate energy shortages and environmental damage.However,the lack of fiber-like moist-electric generators(MEGs)that combine continuous power generation and high electrical output performance has constrained the development of moist-electric in the fields of flexi-ble wearable and self-power supplies.In this work,sodium alginate(SA)/multi-walled carbon nanotubes(MWCNT)fibers with axial heterogeneous(axi-he)of oxygen-containing functional groups(Ocfgs)are prepared through a mold forming method in assistance with the coagulation process.The interaction be-tween axi-he MEG and moisture is investigated by analyzing the electrical signal changes of dried MEG under moisture stimulation.The maximum output voltage and current of axi-he MEG can reach 0.35 V and 1.92μA under the stimulation of moisture.Based on the regulation of Ocfgs,axi-he MEG has a con-tinuous high moist-electric performance and environmental adaptability.The maximum output power density(Pmo)of axi-he MEG with a length of only 2 cm can reach 27.37μW cm-2 at RH=90%,which exceeds most of the MEGs reported in literature.Meanwhile,a continuous output voltage of 0.33-0.37 V for more than 15 h can be obtained from this axi-he MEG.Thus,the axi-he MEG from Ocfg distribution design and mold forming method provides a new way of clean energy generation using moisture from the ambient environment,exhibiting enormous potential in energy supply for Internet of Things(IoT)devices.展开更多
AIM:To evaluate the efficacy of the Tecnis Symfony ZXR00 lens in achieving optimal visual outcomes for cataract surgery patients with axial length(AL)shorter than 24 mm.METHODS:A total of 21 subjects(37 eyes)were subm...AIM:To evaluate the efficacy of the Tecnis Symfony ZXR00 lens in achieving optimal visual outcomes for cataract surgery patients with axial length(AL)shorter than 24 mm.METHODS:A total of 21 subjects(37 eyes)were submitted to cataract surgery and implantation of Tecnis Symfony ZXR00 lens(Johnson&Johnson Vision)was assessed.Patients were examined at 5 m,80 cm,and 40 cm for uncorrected distance visual acuity(UCDVA)and corrected distance visual acuity(CDVA),uncorrected intermediate(UCIVA),and uncorrected near visual acuity(UCNVA).Further,based on the optimal distance correction,the monocular defocusing curve in the range of+0.5 to-3.5 D was investigated.A simple patient-reported spectacle independence questionnaire(PRSIQ)was used to evaluate subjects’subjective feelings about their dependence on glasses at various distances.Multiple linear regression was employed to examine the association amony intraocular lenses(IOLs)diopter,AL,corneal curvature,anterior chamber depth,mean manifest refractive spherical equivalent,pupil,pupil/scan,target refraction,and near vision(logMAR).RESULTS:The study demonstrated enhanced UCNVA alongside comparable distant vision and UCIVA outcomes in eyes with AL shorter than 24 mm.Mean post-operative UCDVA significantly improved from preoperative levels 0.530±0.406(P=0.000).Notably,83.3%of eyes achieved 0.01 logMAR in UCNVA.Five unilateral cases with blended IOL implantation also showed satisfactory visual acuity and satisfaction.The 90.5%(19/21)achieved spectacle independence.The average score for self-reported spectacle-independence on the PRSIQ was 3.52 with a standard deviation of 0.98.The results of the regression analysis revealed that one predictor,the pupil/scan accounted for 27.6%of the variation in near vision[logMAR;F(1,35)=13.33,P<0.01].CONCLUSION:The results affirm the effectiveness of the Tecnis Symfony ZXR00 lens in enhancing visual outcomes for cataract surgery patients with AL shorter than 24 mm.Additionally,the pupil/scan emerges as a critical factor influencing postoperative near vision.展开更多
Axial chain rockbursts(ACRs)repeatedly occur in deep tunnels during drilling and blasting methodology(D&B)within locked-in stress zones,severely hindering construction progress.In extremely cases,ACRs can persist ...Axial chain rockbursts(ACRs)repeatedly occur in deep tunnels during drilling and blasting methodology(D&B)within locked-in stress zones,severely hindering construction progress.In extremely cases,ACRs can persist for 7−10 d and affect areas exceeding 20 m along tunnel axis.Through integrated geological investigations and microseismic(MS)monitoring,the geological characteristics,MS activity patterns,and formation mechanisms of ACRs were analyzed.In tectonically active regions,locked-in stress zones arise from interactions between multiple structural planes.Blasting dynamic disturbances during tunnel excavation in these zones trigger early slippage along structural planes and fractures in the surrounding rock,with MS events developing ahead of the working face.High-energy MS events dominate during the development and occurrence stages of ACRs,extending 20−30 m(3−4 tunnel diameters)ahead of the working face.Following the ACRs,low-energy MS events primarily occur behind the working face.Tensile fracturing is the predominant failure mode during ACRs.Shear and mixed fractures primarily occur within the ACRs zone during the intra-ACR phase.Monitoring MS event locations ahead of the working face provides a reliable approach for prewarning potential ACR-prone zones.展开更多
The efficiency of energy conversion from mechanical to electrical in AC generators is not entirely optimal,as power losses are converted into heat.Accurate thermal modeling and temperature measurement of advanced elec...The efficiency of energy conversion from mechanical to electrical in AC generators is not entirely optimal,as power losses are converted into heat.Accurate thermal modeling and temperature measurement of advanced electric machines with complex structures are mandatory to confirm their reliability and safe operation.In a unique axial transverse flux switching permanent magnet(ATFSPM)generator,due to its high power density,large stray loss from leakage flux,compact topology,and totally enclosed structure,thermal analysis is of paramount significance.In this paper,thermal modeling and analysis of ATFSPM are carried out in detail using a three-dimensional(3D)finite element analysis(FEA)to evaluate the thermal condition for a precise performance improvement.To begin,all loss sources are accurately derived using 3-D FEA and analytical methods,taking into account the temperature dependence of material properties,and then losses are coupled to the thermal model as heat sources.Afterward,aiming for realistic thermal modelling,the convection heat transfer in the different regions of internal and external areas as well as thin layers of interface gaps between components are all considered.In addition,the prototype of ATFSPM is supplied to validate the accuracy of 3-D FEA temperature prediction.Furthermore,a novel technique is carried out to effectively improve thermal performance,enhance the efficiency,and limit hot-spot temperatures.The steady-state and transient temperature results demonstrate the high accuracy of the thermal modeling,enhance the secure operation of the ATFSPM,and facilitate increased loading utilizing the proposed technique.(1)展开更多
In order to study the axial compression characteristics of brick masonry historical buildings, and to better protect and repair traditional mortar-brick masonry historical buildings, axial compression tests were carri...In order to study the axial compression characteristics of brick masonry historical buildings, and to better protect and repair traditional mortar-brick masonry historical buildings, axial compression tests were carried out on three kinds of restored mortar (pure mud mortar, pure mortar, and mud mortar) brick masonry with restored mortar brick masonry as the object of study. The damage modes, axial compression chemical indexes (compressive strength and elastic modulus), load-displacement curves and stress-strain curves of the three kinds of restored mortar brick masonry were obtained. The experimental results show that the compressive strength of mud mortar brick masonry of 1.676 MPa is better than that of pure mud 1.530 MPa and pure mortar 1.471 MPa brick masonry, which is due to the difference in the bond effect between the restored mortar material and the brick block. According to the test results, the compressive strength formula of the restored mortar brick masonry was modified, and the reasons for the difference between the experimental value of the modulus of elasticity of the restored mortar brick masonry and that of the traditional formula and the measured value were compared and analyzed by a factor of 6.73–7.1. Referring to the axial-pressure ontological relationship of the conventional brick masonry, the 4-parameter segmental function expression was proposed for the characterization of the stress-strain relationship of the restored mortar brick masonry with the use of the stress-strain normalization process. The research results provide theoretical support for the inheritance and development of traditional mortar brick masonry historical architecture.展开更多
The global prevalence of myopia is becoming increasingly severe,with epidemiological models predicting that by 2050,approximately 50%of the world’s population will be affected by myopia,and about 10%will suffer from ...The global prevalence of myopia is becoming increasingly severe,with epidemiological models predicting that by 2050,approximately 50%of the world’s population will be affected by myopia,and about 10%will suffer from high myopia.The incidence of high myopia is projected to increase fivefold,making it the leading cause of irreversible vision impairment.Myopia often leads to various complications and has been associated with other ocular diseases,including early-onset cataracts,age-related macular degeneration,and primary open angle glaucoma.As a result,the control and management of myopia have become ongoing and long-term research priorities.The pathogenesis of myopia involves complex multisystem interactions.Current mainstream theories focus primarily on choroidal hypoxia-induced scleral remodeling,with neurotransmitters such as acetylcholine and dopamine playing regulatory roles.However,recent studies have increasingly suggested that changes in nutritional intake,including proteins,fats,and cholesterol,may also be related to myopia development.The role of lipid metabolism in the onset and progression of myopia has gradually attracted growing attention.Therefore,this review aims to systematically elucidate the molecular mechanisms of lipid metabolism regulatory networks in axial myopia,integrating multidimensional factors to provide a theoretical foundation for precision intervention strategies.展开更多
With the continuous increase of aeroengine flight ceiling(>20 km),the thin atmosphere at high altitudes and the size effect all cause the compressor component inlet Reynolds number to decrease rapidly to a critical...With the continuous increase of aeroengine flight ceiling(>20 km),the thin atmosphere at high altitudes and the size effect all cause the compressor component inlet Reynolds number to decrease rapidly to a critical value(approximately 2.0×10^(5)),and the significant transition process on the blade/endwall surface leads to the sharp degradation of compressor performance,which seriously affects the engine fuel consumption and working stability at high altitudes.In this paper,the research progress on the internal flow mechanism and flow control methods of axial compressors at low Reynolds numbers is reviewed from the aspects of quantification and prediction of performance variation,flow loss mechanism related to separation and transition,efficient transition control and flow field organization.The development trend of the low-Reynolds-number effect of axial flow compressors is noted,and the difficulties and application prospects of aerodynamic design and efficient flow control methods for compressors under low Reynolds numbers at high altitudes are discussed.展开更多
AIM:To compare the effects of different types of negative pressure suction on the macular and optic disc retinal vessel density(VD)in myopic patients with different axial lengths(ALs)undergoing femtosecond laser-assis...AIM:To compare the effects of different types of negative pressure suction on the macular and optic disc retinal vessel density(VD)in myopic patients with different axial lengths(ALs)undergoing femtosecond laser-assisted excimer laser in situ keratomileusis(FS-LASIK)by optical coherence tomography angiography(OCTA).METHODS:A prospective,nonrandomized,controlled study.Participants underwent FS-LASIK surgery were divided into the short AL group(SAL,22≤AL<26 mm)and the long AL group(LAL,26≤AL<28 mm)according to the different ALs.Further,the two groups were divided into subgroups according to the corneal flap using VisuMax or WaveLight FS200 femtosecond laser(FS)platform.All patients underwent OCTA before the surgery and 1-day/1-week/1-month after the surgery.ANOVA statistically analyzed data with two-factor repeated measurement in SPSS.RESULTS:Totally 108 participants(108 eyes,18–35y)were divided into SAL group[22 patients(4 males and 18 females)were treated with VisuMax,and 24(3 males and 21 females)were treated with WaveLight FS200]and LAL group[34 patients(4 males and 30 females)were treated with VisuMax,and 28 patients(6 males and 22 females)were treated with WaveLight FS200].In the LAL group,there was no significant difference in macular superficial capillary plexuses vessel density(SCP-VD)in the fovea and perifovea region,but compared with the VisuMax subgroup,SCP-VD in the parafoveal region(t=2.647,P=0.010)and the whole area(t=2.030,P=0.047)in WaveLight FS200 subgroup decreased at one day after the operation and increased to a preoperative level at 1-week and 1-month after operation.There was no significant difference between SCP-VD in the two SAL subgroups,neither of deep capillary plexuses vessel density(DCP-VD)and optic nerve head vessel density(ONH-VD)in the SAL and LAL groups.CONCLUSION:With the increase of AL and suction intensity,a transient decrease of SCP-VD in the macular region is observed at 1d postoperatively during FS-LASIK,and it increases to preoperative level at 1-week and 1-month postoperatively.However,the AL and suction intensity do not affect the macular DCP-VD and ONH-VD.展开更多
AIM:To determine the utility of the RS-1 spectral domain optical coherence tomography(SD-OCT),which incorporates an“OCT Analysis Correction Parameter”for approximating axial length,in comparison with measurements ob...AIM:To determine the utility of the RS-1 spectral domain optical coherence tomography(SD-OCT),which incorporates an“OCT Analysis Correction Parameter”for approximating axial length,in comparison with measurements obtained from the OA-2000.METHODS:Twenty-five right eyes of healthy individuals were included.Two horizontal line scans were conducted using the RS-1,and OCT Analysis Correction Parameters were recorded.Axial length was measured twice per eye using the OA-2000.Correlation between devices was assessed using Pearson correlation coefficient,coefficient of repeatability(CR%),and Bland-Altman analysis.RESULTS:High correlation was found between axial length measurements from RS-1 and OA-2000(r=0.986,P<0.0001).The coefficient of repeatability was 1.56%for RS-1 and 0.115%for OA-2000.Mean axial length was 25.12±1.38 mm for RS-1 and 24.90±1.54 mm for OA-2000,with RS-1 showing a statistically significant larger value(paired t-test,P=0.0009).CONCLUSION:The axial length measurements of RS-1 demonstrate a strong positive correlation with those from the OA-2000.This indicates that it could potentially be used to forecast scan ranges and choose suitable databases according to axial length categories.展开更多
To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The p...To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The par-tial differential equation of galloping with axial time-delay velocity feedback strategy is established based on the variational principle for Hamiltonian.Then,the partial differential equation of galloping is transformed into or-dinary differential equation based on normalization and the Galerkin method.The primary amplitude-frequency response equation,the first-order steady-state approximate solution,and the harmonic amplitude-frequency re-sponse equation are derived by the multiscale method.The impact of different parameters such as time-delay value,control coefficient,and amplitude of external excitation on the galloping response are analyzed.The am-plitude under the primary resonance exhibits periodicity as time-delay value varies.The amplitude diminishes with increased control coefficient and increases with external excitation.Comprehensive consideration of vari-ous influences of parameters on vibration characteristics is crucial when employing the axial time-delay velocity feedback strategy to suppress galloping.Therefore,to achieve the best vibration suppression effect,it is crucial to adjust the time-delay parameter for modifying the range and amplitude of the resonance zone.The conclusions obtained by this study are expected to advance the refinement of active control techniques for iced transmission lines,and may provide valuable insights for practical engineering applications.展开更多
The flow ripple caused by an axial piston pump may lead to pipe vibrations and lower hydraulic component reliability,which are of particular concern in hydraulic systems.The valve plate of the pump is considered the p...The flow ripple caused by an axial piston pump may lead to pipe vibrations and lower hydraulic component reliability,which are of particular concern in hydraulic systems.The valve plate of the pump is considered the part most related to flow ripple,and its structural design is an important topic.In this study,an analytical model for the axial piston pump flow ripple was established and verified using a numerical analysis with computational fluid dynamics(CFD)calculations.Moreover,a parametric analysis of the valve plate was performed to investigate the critical parameters and their ranges.A fast optimization method,the rotation vector optimization method(RVOM),was proposed for the valve plate design and compared with the currently used optimization methods to prove its efficiency.As a constant-pressure pump works in different states of swashplate angle,outlet pressure,and pump speed,an optimization principle for the entire working status was proposed to achieve the overall reduction performance.A test rig for an aircraft hydraulic pump was established,and validation experiments were conducted.It was determined that the optimized pump could achieve reduction at multiple working statuses,and the largest pressure pulsation reduction ratios for the typical speed and speed sweep tests reached 64.7%and 71.7%,respectively.The model and method proposed in this study are proven to be effective and accurate.展开更多
Electrocatalytic CO_(2)-to-CO conversion is crucial for advancing sustainable processes,and providing essential feedstocks for the chemical industry.Cobalt phthalocyanine(CoPc)is a well-established molecular catalyst ...Electrocatalytic CO_(2)-to-CO conversion is crucial for advancing sustainable processes,and providing essential feedstocks for the chemical industry.Cobalt phthalocyanine(CoPc)is a well-established molecular catalyst for this conversion;however,maintaining high selectivity at industrially relevant current densities remains a significant challenge.Herein,we present a Co–N_(5)local structure anchored on nitrogen-doped carbon nanotubes through axial nitrogen coordination engineering to CoPc(CoPc/N-CNTs).The catalyst demonstrates near-unity CO selectivity and a high CO turnover frequency,peaking at 19.2 s^(−1)across a wide range of overpotentials.In flow cell tests,CoPc/N-CNTs achieve a CO Faradaic efficiency exceeding 95%at a current density of−800 mA cm^(−2).When integrated into a membrane electrode assembly,it maintained over 90%CO Faradaic efficiency at an industrial-scale current of−5 A for up to 20 h.Mechanistic studies revealed that Co–N_(5)active sites accelerate*COOH formation and inhibit deeper*CO reduction to CH_(3)OH while reducing HER activity by lowering H_(2)O surface coverage.These findings offer a delicate catalyst design that enables the efficient and sustained conversion of CO_(2)to CO.展开更多
文摘Background: Non-radiographic axial spondyloarthritis is a progressive and disabling inflammatory disease affecting young adults, with limited treatment options. TNFi are more efficacious than JAKi and IL1-7i in nr-ax SPA and it has a well-known safety profile over a longer duration. Recently, many IL-17i and JAKi were approved for the treatment of nr-ax SPA;however, data comparing IL1-7i and JAKi in terms of efficacy and safety is lacking. This systematized review aimed to compare the existing efficacy and safety data of JAKi vs IL-17i in the treatment of patients with nr-ax SPA. Methods: A systematic literature search was performed using relevant keywords in many databases. According to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA, 2020), relevant articles were included and evaluated in this review. Efficacy and safety data were collected, analyzed and compared through week 52. The first check was done by the end of week 14 and week 16 for upadacitinib and IL-17i respectively. Results: Data from four RCTs evaluating upadacitinib, secukinumab, ixekizumab, and bimekizumab comprising 1425 patients were analyzed. Overall, a comparable efficacy and safety profile were observed across different treatment arms through week 52;however, non-significant variations were encountered in some outcome measures. The primary endpoint among these RCTs (ASAS40 response rate) was met and it was higher in patients treated with bimekizumab 160 mg sc Q 4 weeks in TNFi non responders (48%) and lowest in ixekizumab 80 mg sc Q 4 weeks treated patients, (35%) (p Conclusion: The above-mentioned three IL-17i and the only one JAKi demonstrated comparable safety and efficacy profiles with some minor variations. A head-to-head trial comparing the effectiveness and safety characteristics of JAKi vs IL-17i may be needed in patients with active nr-ax SpA.
基金support by the National Natural Science Foundation of China(Grant No.12322513)USTC Research Funds of the Double First-Class Initiative+1 种基金CAS Project for Young Scientists in Basic Research(Grant No.YSBR060)supported by the Office of Fusion Energy Sciences under Award No.DE-SC0023423。
文摘Strong multi-kilotesla magnetic fields have various applications in high-energy density science and laboratory astrophysics, but they are not readily available. In our previous work [Y. Shi et al., Phys. Rev. Lett. 130, 155101(2023)], we developed a novel approach for generating such fields using multiple conventional laser beams with a twist in the pointing direction. This method is particularly well-suited for multi-kilojoule petawatt-class laser systems like SG-Ⅱ UP, which are designed with multiple linearly polarized beamlets. Utilizing three-dimensional kinetic particle-in-cell simulations, we examine critical factors for a proof-of-principle experiment, such as laser polarization, relative pulse delay,phase offset, pointing stability, and target configuration, and their impact on magnetic field generation. Our general conclusion is that the approach is very robust and can be realized under a wide range of laser parameters and plasma conditions. We also provide an in-depth analysis of the axial magnetic field configuration, azimuthal electron current, and electron and ion orbital angular momentum densities.Supported by a simple model, our analysis shows that the axial magnetic field decays owing to the expansion of hot electrons.
基金Chongqing Fuling District Science and Health Joint Medical Research Project(2022KWLH069)。
文摘Objective:To investigate the influence of axial length(AL),corneal curvature(CR),and the ratio of axial length to corneal radius of curvature(AL/CR)on myopia in children,and to evaluate the accuracy and specificity of AL/CR in diagnosing myopia in children.Methods:A cross-sectional study was conducted.A total of 200 children(400 eyes)aged 6-12 years were recruited from the ophthalmology outpatient clinic of Fuling District People’s Hospital from December 2022 to December 2023.AL,CR,and AL/CR were measured,and comprehensive optometry was performed under cycloplegia,with the results recorded in spherical equivalent(SE)form.Results:A total of 200 subjects(400 eyes)were included in this study,of which 330 eyes(82.50%)were myopic.No significant differences in CR were observed among different refractive groups,while significant differences were noted in SE,AL,and AL/CR.The AL and AL/CR ratios were higher in myopic eyes compared to emmetropic and hyperopic eyes.Using cycloplegia as the gold standard,SE in the myopia group was correlated with AL,AL/CR,and CR,with stronger correlations observed with AL and AL/CR.An AL/CR value>3 demonstrated a sensitivity of 0.918,specificity of 0.786,misdiagnosis rate of 0.214,missed diagnosis rate of 0.082,and accuracy of 89.5%in diagnosing myopia.Conclusion:AL and AL/CR values are highly correlated with SE,with the strongest correlation observed in the myopia group.The AL/CR value exhibits high diagnostic value in determining myopia in children.
基金supported by the National Natural Science Foundation of China(Grant No.52271277)the Natural Science Foundation of Jiangsu Province(Grant No.BK20211343)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.SJCX23_2150).
文摘This study focused on the buckling characteristics of egg-shaped shells with single crack and double cracks under axial pressure.First,the geometric parameters of the egg-shaped shell were designed,and a numerical model of the egg-shaped shell was established.Then,the initial crack was introduced into the equatorial weld of the egg-shaped shell,and the effects of the crack on the buckling characteristics under different wall thicknesses were explored,as were the effects of the single crack direction,double crack angle and spacing on the buckling characteristics.Finally,crack-free,single crack and double crack egg-shaped shells were fabricated from Q235 steel.The buckling loads and failure modes of the three egg-shaped shells were obtained via axial compression experiments.The numerical critical buckling loads and buckling modes were compared with the experimental results to verify the accuracy of the numerical model.The results of this study are valuable for the design of egg-shaped shells under axial loading.
文摘The effects of Reynolds number on the compressor efficiency are investigated by tests on three highlyloaded 10-stage axial compressors.The tests are conducted by adjusting the inlet total pressure,and thus different Reynolds numbers are obtained.The results indicate that the compressor efficiency decreases when the Reynolds number decreases.Based on the test results,reasonable correlations between the Reynolds number and compressor efficiency for each of the three compressors are obtained.The comparison between the test result-deduced correlations and Wassell correlations indicates that the effects of Reynolds number on the efficiency predicted by the Wassell correlations are less than those obtained by the test result-deduced correlations.Owing to the complex loss models and flow behavior in highly-loaded multi-stage compressors,additional influence factors,including the tip clearance and the compressor inlet duct design,should be considered for performance correlations.Nevertheless,the Wassell correlations are valid for the tendency prediction of performance changes relating to the Reynolds number,while accurate correlations still largely depend on the specific test results.
文摘Steel cylindrical shells are widely used in engineering structures due to their high strength-to-weight ratio,but they are vulnerable to buckling under axial loads.To address this limitation,fiber-reinforced polymer(FRP)composites have emerged as promising materials for structural reinforcement.This study investigates the buckling behavior of steel cylindrical shells reinforced with inner and outer layers of polymer composite materials under axial compression.Using analytical and numerical modeling methods,the critical buckling loads for different reinforcement options were evaluated.Two-sided glass fiber reinforced plastic(GFRP)or carbon fiber reinforced plastic(CFRP)coatings,as well as combined coatings with layers of different composites,were considered.GFRP+CFRPIn the calculations,the coatings were treated as homogeneous orthotropic materials with equivalent averaged elastic characteristics.The numerical analysis revealed that CFRP reinforcement achieved the highest increase in buckling load,with improvements ranging from 9.84%to 47.29%,depending on the composite thickness and steel shell thickness.GFRP reinforcement,while beneficial,demonstrated a lower effectiveness,with buckling load increases between 5.89%and 19.30%.The hybrid reinforcement provided an optimal balance,improving buckling resistance by GFRP+CFRP6.94%to 43.95%.Statistical analysis further identified composite type and thickness as the most significant factors affecting buckling performance.The findings suggest that CFRP is the preferred reinforcement material,especially when applied to thin-walled cylindrical shells,while hybrid reinforcements can be effectively utilized for structures requiring a balance between stiffness and ductility.These insights provide a foundation for optimizing FRP reinforcement strategies to enhance the structural integrity of steel shells in engineering applications.
基金Supported by the Medical Science and Technology Project of Zhejiang Province of China(No.2020KY191).
文摘AIM:To investigate the ocular biological characteristics of children with myopia and rapid axial length(AL)changes prescribed spectacles with highly aspherical lenslets(HAL).METHODS:Data were collected from 156 children(252 eyes)with myopia and HAL treatment who were aged 7-13 and had rapid AL changes.The participants were divided into groups with AL reduction and elongation according to the changes in AL within 6mo.Paired t-tests were used to compare the ocular biological parameters at baseline and after rapid changes post-HAL treatment.Pearson’s correlation analysis was used to determine the association between the ocular parameters and AL changes.RESULTS:The ocular biological parameters significantly changed in the children with myopia and rapid AL changes after HAL treatment.In the group with AL reduction,the anterior chamber depth(ACD)and vitreous chamber depth(VCD)decreased.The crystalline lens thickness(CLT)increased,corneal flat keratometry(FK)decreased,and steep keratometry(SK)increased(all P<0.001).The eyes in the group with AL elongation had increased ACD and VCD and steepened SK,but the CLT or FK findings were not different.AL change was negatively associated with baseline astigmatism(r=-0.171;P=0.007).CONCLUSION:In the eyes with HAL treatment,decreased ACD and VCD,thickened CLT,flattened FK,and steepened SK are observed during AL reduction.Lower baseline astigmatism is associated with AL reduction.The AL reduction may suggest the potential efficacy of HAL intervention in myopia control,while providing evidence for optimizing personalized myopia management strategies.Further longitudinal studies are warranted to validate whether rapid AL changes predict sustained treatment efficacy.
基金supported by the National Natural Science Foundation of China(No.22073015)the National Key R&D Program of China(No.2022YFB3704600).
文摘Moist-electric generation,a green and environmentally friendly energy harvesting technology,is undoubt-edly one of the effective methods to alleviate energy shortages and environmental damage.However,the lack of fiber-like moist-electric generators(MEGs)that combine continuous power generation and high electrical output performance has constrained the development of moist-electric in the fields of flexi-ble wearable and self-power supplies.In this work,sodium alginate(SA)/multi-walled carbon nanotubes(MWCNT)fibers with axial heterogeneous(axi-he)of oxygen-containing functional groups(Ocfgs)are prepared through a mold forming method in assistance with the coagulation process.The interaction be-tween axi-he MEG and moisture is investigated by analyzing the electrical signal changes of dried MEG under moisture stimulation.The maximum output voltage and current of axi-he MEG can reach 0.35 V and 1.92μA under the stimulation of moisture.Based on the regulation of Ocfgs,axi-he MEG has a con-tinuous high moist-electric performance and environmental adaptability.The maximum output power density(Pmo)of axi-he MEG with a length of only 2 cm can reach 27.37μW cm-2 at RH=90%,which exceeds most of the MEGs reported in literature.Meanwhile,a continuous output voltage of 0.33-0.37 V for more than 15 h can be obtained from this axi-he MEG.Thus,the axi-he MEG from Ocfg distribution design and mold forming method provides a new way of clean energy generation using moisture from the ambient environment,exhibiting enormous potential in energy supply for Internet of Things(IoT)devices.
文摘AIM:To evaluate the efficacy of the Tecnis Symfony ZXR00 lens in achieving optimal visual outcomes for cataract surgery patients with axial length(AL)shorter than 24 mm.METHODS:A total of 21 subjects(37 eyes)were submitted to cataract surgery and implantation of Tecnis Symfony ZXR00 lens(Johnson&Johnson Vision)was assessed.Patients were examined at 5 m,80 cm,and 40 cm for uncorrected distance visual acuity(UCDVA)and corrected distance visual acuity(CDVA),uncorrected intermediate(UCIVA),and uncorrected near visual acuity(UCNVA).Further,based on the optimal distance correction,the monocular defocusing curve in the range of+0.5 to-3.5 D was investigated.A simple patient-reported spectacle independence questionnaire(PRSIQ)was used to evaluate subjects’subjective feelings about their dependence on glasses at various distances.Multiple linear regression was employed to examine the association amony intraocular lenses(IOLs)diopter,AL,corneal curvature,anterior chamber depth,mean manifest refractive spherical equivalent,pupil,pupil/scan,target refraction,and near vision(logMAR).RESULTS:The study demonstrated enhanced UCNVA alongside comparable distant vision and UCIVA outcomes in eyes with AL shorter than 24 mm.Mean post-operative UCDVA significantly improved from preoperative levels 0.530±0.406(P=0.000).Notably,83.3%of eyes achieved 0.01 logMAR in UCNVA.Five unilateral cases with blended IOL implantation also showed satisfactory visual acuity and satisfaction.The 90.5%(19/21)achieved spectacle independence.The average score for self-reported spectacle-independence on the PRSIQ was 3.52 with a standard deviation of 0.98.The results of the regression analysis revealed that one predictor,the pupil/scan accounted for 27.6%of the variation in near vision[logMAR;F(1,35)=13.33,P<0.01].CONCLUSION:The results affirm the effectiveness of the Tecnis Symfony ZXR00 lens in enhancing visual outcomes for cataract surgery patients with AL shorter than 24 mm.Additionally,the pupil/scan emerges as a critical factor influencing postoperative near vision.
基金Projects(52222810,52178383)supported by the National Natural Science Foundation of China。
文摘Axial chain rockbursts(ACRs)repeatedly occur in deep tunnels during drilling and blasting methodology(D&B)within locked-in stress zones,severely hindering construction progress.In extremely cases,ACRs can persist for 7−10 d and affect areas exceeding 20 m along tunnel axis.Through integrated geological investigations and microseismic(MS)monitoring,the geological characteristics,MS activity patterns,and formation mechanisms of ACRs were analyzed.In tectonically active regions,locked-in stress zones arise from interactions between multiple structural planes.Blasting dynamic disturbances during tunnel excavation in these zones trigger early slippage along structural planes and fractures in the surrounding rock,with MS events developing ahead of the working face.High-energy MS events dominate during the development and occurrence stages of ACRs,extending 20−30 m(3−4 tunnel diameters)ahead of the working face.Following the ACRs,low-energy MS events primarily occur behind the working face.Tensile fracturing is the predominant failure mode during ACRs.Shear and mixed fractures primarily occur within the ACRs zone during the intra-ACR phase.Monitoring MS event locations ahead of the working face provides a reliable approach for prewarning potential ACR-prone zones.
基金supported by research grants of the Iran National Science Foundation(INSF)under grant No.98002866。
文摘The efficiency of energy conversion from mechanical to electrical in AC generators is not entirely optimal,as power losses are converted into heat.Accurate thermal modeling and temperature measurement of advanced electric machines with complex structures are mandatory to confirm their reliability and safe operation.In a unique axial transverse flux switching permanent magnet(ATFSPM)generator,due to its high power density,large stray loss from leakage flux,compact topology,and totally enclosed structure,thermal analysis is of paramount significance.In this paper,thermal modeling and analysis of ATFSPM are carried out in detail using a three-dimensional(3D)finite element analysis(FEA)to evaluate the thermal condition for a precise performance improvement.To begin,all loss sources are accurately derived using 3-D FEA and analytical methods,taking into account the temperature dependence of material properties,and then losses are coupled to the thermal model as heat sources.Afterward,aiming for realistic thermal modelling,the convection heat transfer in the different regions of internal and external areas as well as thin layers of interface gaps between components are all considered.In addition,the prototype of ATFSPM is supplied to validate the accuracy of 3-D FEA temperature prediction.Furthermore,a novel technique is carried out to effectively improve thermal performance,enhance the efficiency,and limit hot-spot temperatures.The steady-state and transient temperature results demonstrate the high accuracy of the thermal modeling,enhance the secure operation of the ATFSPM,and facilitate increased loading utilizing the proposed technique.(1)
基金funded by National Key R&D Program of China(No.2022YFC3803500).
文摘In order to study the axial compression characteristics of brick masonry historical buildings, and to better protect and repair traditional mortar-brick masonry historical buildings, axial compression tests were carried out on three kinds of restored mortar (pure mud mortar, pure mortar, and mud mortar) brick masonry with restored mortar brick masonry as the object of study. The damage modes, axial compression chemical indexes (compressive strength and elastic modulus), load-displacement curves and stress-strain curves of the three kinds of restored mortar brick masonry were obtained. The experimental results show that the compressive strength of mud mortar brick masonry of 1.676 MPa is better than that of pure mud 1.530 MPa and pure mortar 1.471 MPa brick masonry, which is due to the difference in the bond effect between the restored mortar material and the brick block. According to the test results, the compressive strength formula of the restored mortar brick masonry was modified, and the reasons for the difference between the experimental value of the modulus of elasticity of the restored mortar brick masonry and that of the traditional formula and the measured value were compared and analyzed by a factor of 6.73–7.1. Referring to the axial-pressure ontological relationship of the conventional brick masonry, the 4-parameter segmental function expression was proposed for the characterization of the stress-strain relationship of the restored mortar brick masonry with the use of the stress-strain normalization process. The research results provide theoretical support for the inheritance and development of traditional mortar brick masonry historical architecture.
基金Supported by the National Natural Science Foundation of China(No.82000922,No.81870647).
文摘The global prevalence of myopia is becoming increasingly severe,with epidemiological models predicting that by 2050,approximately 50%of the world’s population will be affected by myopia,and about 10%will suffer from high myopia.The incidence of high myopia is projected to increase fivefold,making it the leading cause of irreversible vision impairment.Myopia often leads to various complications and has been associated with other ocular diseases,including early-onset cataracts,age-related macular degeneration,and primary open angle glaucoma.As a result,the control and management of myopia have become ongoing and long-term research priorities.The pathogenesis of myopia involves complex multisystem interactions.Current mainstream theories focus primarily on choroidal hypoxia-induced scleral remodeling,with neurotransmitters such as acetylcholine and dopamine playing regulatory roles.However,recent studies have increasingly suggested that changes in nutritional intake,including proteins,fats,and cholesterol,may also be related to myopia development.The role of lipid metabolism in the onset and progression of myopia has gradually attracted growing attention.Therefore,this review aims to systematically elucidate the molecular mechanisms of lipid metabolism regulatory networks in axial myopia,integrating multidimensional factors to provide a theoretical foundation for precision intervention strategies.
基金co-supported by the National Natural Science Foundation of China(No.52306053)the Science Center for Gas Turbine Project,China(No.P2022-B-Ⅱ-005-001)the National Science and Technology Major Project of China(No.2017-Ⅱ-0010-0024)。
文摘With the continuous increase of aeroengine flight ceiling(>20 km),the thin atmosphere at high altitudes and the size effect all cause the compressor component inlet Reynolds number to decrease rapidly to a critical value(approximately 2.0×10^(5)),and the significant transition process on the blade/endwall surface leads to the sharp degradation of compressor performance,which seriously affects the engine fuel consumption and working stability at high altitudes.In this paper,the research progress on the internal flow mechanism and flow control methods of axial compressors at low Reynolds numbers is reviewed from the aspects of quantification and prediction of performance variation,flow loss mechanism related to separation and transition,efficient transition control and flow field organization.The development trend of the low-Reynolds-number effect of axial flow compressors is noted,and the difficulties and application prospects of aerodynamic design and efficient flow control methods for compressors under low Reynolds numbers at high altitudes are discussed.
基金Supported by Wu Jieping Medical Foundation(No.320.6750.2021-4-15).
文摘AIM:To compare the effects of different types of negative pressure suction on the macular and optic disc retinal vessel density(VD)in myopic patients with different axial lengths(ALs)undergoing femtosecond laser-assisted excimer laser in situ keratomileusis(FS-LASIK)by optical coherence tomography angiography(OCTA).METHODS:A prospective,nonrandomized,controlled study.Participants underwent FS-LASIK surgery were divided into the short AL group(SAL,22≤AL<26 mm)and the long AL group(LAL,26≤AL<28 mm)according to the different ALs.Further,the two groups were divided into subgroups according to the corneal flap using VisuMax or WaveLight FS200 femtosecond laser(FS)platform.All patients underwent OCTA before the surgery and 1-day/1-week/1-month after the surgery.ANOVA statistically analyzed data with two-factor repeated measurement in SPSS.RESULTS:Totally 108 participants(108 eyes,18–35y)were divided into SAL group[22 patients(4 males and 18 females)were treated with VisuMax,and 24(3 males and 21 females)were treated with WaveLight FS200]and LAL group[34 patients(4 males and 30 females)were treated with VisuMax,and 28 patients(6 males and 22 females)were treated with WaveLight FS200].In the LAL group,there was no significant difference in macular superficial capillary plexuses vessel density(SCP-VD)in the fovea and perifovea region,but compared with the VisuMax subgroup,SCP-VD in the parafoveal region(t=2.647,P=0.010)and the whole area(t=2.030,P=0.047)in WaveLight FS200 subgroup decreased at one day after the operation and increased to a preoperative level at 1-week and 1-month after operation.There was no significant difference between SCP-VD in the two SAL subgroups,neither of deep capillary plexuses vessel density(DCP-VD)and optic nerve head vessel density(ONH-VD)in the SAL and LAL groups.CONCLUSION:With the increase of AL and suction intensity,a transient decrease of SCP-VD in the macular region is observed at 1d postoperatively during FS-LASIK,and it increases to preoperative level at 1-week and 1-month postoperatively.However,the AL and suction intensity do not affect the macular DCP-VD and ONH-VD.
文摘AIM:To determine the utility of the RS-1 spectral domain optical coherence tomography(SD-OCT),which incorporates an“OCT Analysis Correction Parameter”for approximating axial length,in comparison with measurements obtained from the OA-2000.METHODS:Twenty-five right eyes of healthy individuals were included.Two horizontal line scans were conducted using the RS-1,and OCT Analysis Correction Parameters were recorded.Axial length was measured twice per eye using the OA-2000.Correlation between devices was assessed using Pearson correlation coefficient,coefficient of repeatability(CR%),and Bland-Altman analysis.RESULTS:High correlation was found between axial length measurements from RS-1 and OA-2000(r=0.986,P<0.0001).The coefficient of repeatability was 1.56%for RS-1 and 0.115%for OA-2000.Mean axial length was 25.12±1.38 mm for RS-1 and 24.90±1.54 mm for OA-2000,with RS-1 showing a statistically significant larger value(paired t-test,P=0.0009).CONCLUSION:The axial length measurements of RS-1 demonstrate a strong positive correlation with those from the OA-2000.This indicates that it could potentially be used to forecast scan ranges and choose suitable databases according to axial length categories.
基金supported by the National Natural Science Foundation of China(Grant No.51507106)China Postdoctoral Science Foundation(Grant No.2021M702371)。
文摘To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The par-tial differential equation of galloping with axial time-delay velocity feedback strategy is established based on the variational principle for Hamiltonian.Then,the partial differential equation of galloping is transformed into or-dinary differential equation based on normalization and the Galerkin method.The primary amplitude-frequency response equation,the first-order steady-state approximate solution,and the harmonic amplitude-frequency re-sponse equation are derived by the multiscale method.The impact of different parameters such as time-delay value,control coefficient,and amplitude of external excitation on the galloping response are analyzed.The am-plitude under the primary resonance exhibits periodicity as time-delay value varies.The amplitude diminishes with increased control coefficient and increases with external excitation.Comprehensive consideration of vari-ous influences of parameters on vibration characteristics is crucial when employing the axial time-delay velocity feedback strategy to suppress galloping.Therefore,to achieve the best vibration suppression effect,it is crucial to adjust the time-delay parameter for modifying the range and amplitude of the resonance zone.The conclusions obtained by this study are expected to advance the refinement of active control techniques for iced transmission lines,and may provide valuable insights for practical engineering applications.
基金Supported by National Natural Science Foundation of China(Grant No.51975025)National Key Research and Development Program of China(Grant No.2019YFB2004500)。
文摘The flow ripple caused by an axial piston pump may lead to pipe vibrations and lower hydraulic component reliability,which are of particular concern in hydraulic systems.The valve plate of the pump is considered the part most related to flow ripple,and its structural design is an important topic.In this study,an analytical model for the axial piston pump flow ripple was established and verified using a numerical analysis with computational fluid dynamics(CFD)calculations.Moreover,a parametric analysis of the valve plate was performed to investigate the critical parameters and their ranges.A fast optimization method,the rotation vector optimization method(RVOM),was proposed for the valve plate design and compared with the currently used optimization methods to prove its efficiency.As a constant-pressure pump works in different states of swashplate angle,outlet pressure,and pump speed,an optimization principle for the entire working status was proposed to achieve the overall reduction performance.A test rig for an aircraft hydraulic pump was established,and validation experiments were conducted.It was determined that the optimized pump could achieve reduction at multiple working statuses,and the largest pressure pulsation reduction ratios for the typical speed and speed sweep tests reached 64.7%and 71.7%,respectively.The model and method proposed in this study are proven to be effective and accurate.
基金the National Key Research and Development Program of China(2022YFA1505700)the Fundamental Research Funds for the Central Universities(ZYGX2022J012)+2 种基金the NSFC(52171201,22278067,22322201,22201272)the Central Government Funds of Guiding Local Scientific and Technological Development for Sichuan Province(2024ZYD0152)the Natural Science Foundation of Sichuan Province(2025NSFJQ0017,2024NSFSC1107,2024NSFSC1104,2023NSFSC0094)。
文摘Electrocatalytic CO_(2)-to-CO conversion is crucial for advancing sustainable processes,and providing essential feedstocks for the chemical industry.Cobalt phthalocyanine(CoPc)is a well-established molecular catalyst for this conversion;however,maintaining high selectivity at industrially relevant current densities remains a significant challenge.Herein,we present a Co–N_(5)local structure anchored on nitrogen-doped carbon nanotubes through axial nitrogen coordination engineering to CoPc(CoPc/N-CNTs).The catalyst demonstrates near-unity CO selectivity and a high CO turnover frequency,peaking at 19.2 s^(−1)across a wide range of overpotentials.In flow cell tests,CoPc/N-CNTs achieve a CO Faradaic efficiency exceeding 95%at a current density of−800 mA cm^(−2).When integrated into a membrane electrode assembly,it maintained over 90%CO Faradaic efficiency at an industrial-scale current of−5 A for up to 20 h.Mechanistic studies revealed that Co–N_(5)active sites accelerate*COOH formation and inhibit deeper*CO reduction to CH_(3)OH while reducing HER activity by lowering H_(2)O surface coverage.These findings offer a delicate catalyst design that enables the efficient and sustained conversion of CO_(2)to CO.
