Aerodynamic performances of axial compressors are significantly affected by variation of Reynolds number in aero-engines.In the design and analysis of compressors,previous correction methods for cascades and stages ha...Aerodynamic performances of axial compressors are significantly affected by variation of Reynolds number in aero-engines.In the design and analysis of compressors,previous correction methods for cascades and stages have difficulties in predicting comprehensively Reynolds number effects on airfoils,matching and characteristics curves.This study proposes Re-correction models for loss,deviation angle and endwall blockage based on classical theories and cascade tests,and loss and deviation models show good agreement in test data of NACA65 and C4 cascades.Throughflow method considering Reynolds number effects is developed by integrating the correction models into a verified Streamline Curvature(SLC)tool.A three-stage axial compressor is investigated through SLC and CFD methods from design Reynolds number(Red=2106)to low Re=4104,and the numerical methods are validated with test data of characteristic curves and spanwise distributions at Red.With Re reduction,SLC method with correction models well predicts variation in overall performances compared with CFD calculations and Wassell's model.Streamwise and spanwise matching such as total pressure and loss distributions in SLC predictions are basically consistent with those in CFD results at near-stall points under design and low Reynolds numbers.SLC and CFD methods share similar detections of stall risks in the third stage(Stg3),and their analyses of diffusion processes deviate to some extent due to different predictions in separated endwall flow.The correction models can be adopted to consider Reynolds number effects in through-flow design and analysis of axial compressors.展开更多
Internal solitary waves(ISWs)are an essential dynamic process in the ocean due to their large amplitude and long propagation distance.Traditional satellite observations provide only twodimensional observations of ocea...Internal solitary waves(ISWs)are an essential dynamic process in the ocean due to their large amplitude and long propagation distance.Traditional satellite observations provide only twodimensional observations of ocean signatures induced by ISWs.The Surface Water and Ocean Topography(SWOT)satellite has drawn significant attention due to its high resolution and threedimensional observation capabilities.SWOT can generate high-precision three-dimensional sea surface topography,capture sea surface undulations,and reveal ISW-related surface oscillations,thus offering a new perspective for studying ISWs.We collected 43 SWOT observations with clear ISW signatures in the Lombok Strait from August 2023 to June 2024.Based on collected data,the ISW imaging characteristics and distributions were analyzed,and the ISW-related sea level anomaly(SLA)data were measured by the SWOT to calculate the ISW amplitude and reveal the amplitude variations during the propagation along the wave crest.The ISW amplitudes generally range between 10 and 100 m,with most ISW amplitudes between 20 and 40 m.By analyzing two consecutive generated ISW packets,we identified the spreading effect along ISW wave crests,which manifests as ISW amplitude decrease with increase in propagation distance,and the amplitude distribution is non-uniform along the wave crest.Further analysis of the propagation paths of the maximum amplitude of ISW moving northward through the Lombok Strait revealed that these maxima are predominantly oriented in northeast direction.Finally,the relationship between the amplitude of ISW and the resulting SLA was analyzed.The Pearson correlation coefficient between these two variables is as high as 0.90,which suggests a strong positive correlation between amplitude and SLA.Furthermore,this relationship is closely related to the water depth,indicating that the three-dimensional sea surface observations provided by SWOT offer crucial observational data for the inversion of amplitudes of ISW.展开更多
Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on...Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on traditional thermal processing or direct ink writing three-dimensional(3D)printing.These methods are not conducive to manufacturing complex structures and present challenges such as time inefficiency,poor accuracy,and the necessity of multiple steps,significantly limiting SR applications.In this study,we developed an SR-based ink suitable for vat photopolymerization 3D printing using a multi-thiol monomer.This ink enables the one-step fabrication of complex architectures with high printing resolution at the micrometer scale,providing excellent mechanical strength and superior chemical stability.Specifically,the optimized 3D printing SR-20 exhibits a tensile stress of 1.96 MPa,an elongation at break of 487.9%,and an elastic modulus of 225.4 kPa.Additionally,the 3D-printed SR samples can withstand various solvents(acetone,toluene,and tetrahydrofuran)and endure temperatures ranging from-50℃ to 180℃,demonstrating superior stability.As a emonstration of the application,we successfully fabricated a series of SR-based soft pneumatic actuators and grippers in a single step with this technology,allowing for free assembly for the first time.This ultraviolet-curable SR,with high printing resolution and exceptional stability performance,has significant potential to enhance the capabilities of 3D printing for applications in soft actuators,robotics,flexible electronics,and medical devices.展开更多
Unmanned aerial vehicle laser scanning(ULS)and terrestrial laser scanning(TLS)systems are effective ways to capture forest structures from top and side views,respectively.The registration of TLS and ULS data is a prer...Unmanned aerial vehicle laser scanning(ULS)and terrestrial laser scanning(TLS)systems are effective ways to capture forest structures from top and side views,respectively.The registration of TLS and ULS data is a prerequisite for a comprehensive forest structure representation.Conventional registration methods based on geometric features(e.g.,points,lines,and planes)are likely to fail due to the irregular natural point distributions of forest point clouds.Currently,automatic registration methods for forest point clouds typically rely on tree attributes(such as tree position and stem diameter).However,these methods are often unsuitable for forests with diverse compositions,complex terrains,irregular tree layouts,and insufficient common trees.In this study,an automated method is proposed to register ULS and TLS forest point clouds using ground points as registration primitives,which operates independently of tree attribute extraction and is estimated to reduce processing time by over 50%.A new evaluation method for registration accuracy evaluation is proposed,where transformation parameters from each TLS scan to the ULS obtained by the proposed registration algorithm are used to derive transformation parameters between TLS scans,which are then compared to reference parameters obtained using artificial spherical targets.Conventional ULS-TLS registration evaluation methods mostly rely on the manual corresponding points selection that is subject to inherent subjective errors,or control points in both TLS and ULS data that are difficult to collect.The proposed method presents an objective and accurate solution for ULS-TLS registration accuracy evaluation that effectively eliminates these limitations.The proposed method was tested on 12 plots with diverse stem densities,tree species,and altitudes located in a mountain forest.A total of 124 TLS scans were successfully registered to ULS data.The registration accuracy was assessed using both the conventional evaluation method and the proposed new evaluation method,with average rotation errors of 2.03 and 2.06 mrad,and average translation errors of 7.63 and 6.51 cm,respectively.The registration accuracies demonstrate that the proposed algorithm effectively and accurately registers TLS to ULS point clouds.展开更多
Personal care products(PCPs)are a class of emerging pollutants that have attracted public concern owing to their harmful effects on humans and the environment.Biomonitoring data is valuable for insight the levels of P...Personal care products(PCPs)are a class of emerging pollutants that have attracted public concern owing to their harmful effects on humans and the environment.Biomonitoring data is valuable for insight the levels of PCPs in the human body and can be crucial for identifying potential health hazards.To gain a better understanding of timely exposure profiles and health risk of reproductive-age population to PCPs,we determined six parabens,six benzophenone-type ultraviolet filters,and three disinfectants in 256 urine samples collected from young adults aged 18-44 years in Beijing,China.The urinary levels of benzophenone-3(BP-3)and 4-hydroxybenzophenone(4-OHBP)were significantly higher in summer compared to winter,suggesting these compounds have different seasonal usage patterns.Moreover,the total concentration of 15 PCPs in female was 430 ng/mL,approximately two times higher than that in male.P-chloro-m-xylenol(PCMX),as a new type of antibacterial agent,has the greatest level among all target analytes,indicating the increasingly use of this antibacterial alternative recently.Five potential influencing factors that lead to the elevated exposure level of PCPs were identified.Over 19%of the target population had a high hazard index value(greater than 1)which was attributed to exposure to propyl paraben(PrP),benzophenone-1(BP-1),BP-3 and PCMX,indicating that PCPs may pose a relatively high exposure risk at environmental levels that should be a cause for concern.展开更多
Research on the application of machine learning(ML)models to landslide susceptibility assessments has gained popularity in recent years,with a focus primarily on topographic factors derived from digital elevation mode...Research on the application of machine learning(ML)models to landslide susceptibility assessments has gained popularity in recent years,with a focus primarily on topographic factors derived from digital elevation models(DEMs).However,few studies have focused on the explanatory effects of these factors on different models,i.e.whether DEM-based factors affect different models in the same way.This study investigated whether different ML models could yield consistent interpretations of DEM-based factors using explanatory algorithms.Six ML models,including a support vector machine,a neural network,extreme gradient boosting,a random forest,linear regression,and K-nearest neighbors,were trained and evaluated on five geospatial datasets derived from different DEMs.Each dataset contained eight DEM-based and six non-DEM-based factors from 8912 landslide samples.Model performance was assessed using accuracy,precision,recall rate,F1-score,kappa coefficient,and receiver operating characteristic curves.Explanatory analyses,including Shapley additive explanations and partial dependence plots,were also employed to investigate the effects of topographic factors on landslide susceptibility.The results indicate that DEM-based factors consistently influenced different ML models across the datasets.Furthermore,tree-based models outperformed the other models in almost all datasets,while the most suitable DEMs were obtained from Copernicus and TanDEM-X.In addition,the concave surface without potholes on steep slopes are ideal topographic conditions for landslide formation in the study area.This study can benefit the wider landslide research community by clarifying how topographic factors affect ML models.展开更多
This paper presents an air quality simulation model that incorporates shipping activities and weather conditions,with a case study of Hainan Island to examine the impact of ship emissions on air quality.The findings r...This paper presents an air quality simulation model that incorporates shipping activities and weather conditions,with a case study of Hainan Island to examine the impact of ship emissions on air quality.The findings reveal that the density of automatic identification system(AIS)signals is particularly high in the southern coastal regions.The results showed that the annual ship emissions recorded the highest density of 896.7 tons/0.01°,49.8 tons/0.01°,1139.7 tons/0.01°,and 122,000 tons/0.01°for sulfur oxides(SO_(x)),particulate matter(PM),nitrogen oxides(NOx),and carbon dioxide(CO_(2)),respectively.Furthermore,the partial distributions of these emissions were not significantly affected by the seasons.Ships within twelve nautical miles of Hainan coastlines emit approximately 2817.7 tons of SO_(x),14,686.4 tons of NO_(x),630.4 tons of PM_(2.5),and 416.9 tons of hydrocarbons(HC)annually.These emissions are primarily concentrated in the sea areas surrounding the ports of Haikou,Yangpu,Basuo,and Sanya.Ships manufactured between 2000 and 2010 have contributed significantly to air pollution,with SO_(x) and HC emissions accounting for approximately 51%and 56% of total emissions,respectively.However,for shipsmanufactured after 2016,these proportions have dropped to approximately 10%.In terms of air pollutants fromship emissions in Hainan Island,the spatial distribution of their contributions is significantly uneven.The impact of PM2.5 differs significantly depending on the season,with the concentrations being substantially higher during Spring.However,the proportions of O3 and other pollutants do not vary significantly,except during Spring.展开更多
The critical conditions for aeroelastic stability and the stability boundaries of a flexible two-dimensional heated panel subjected to an impinging oblique shock are considered using theoretical analysis and numerical...The critical conditions for aeroelastic stability and the stability boundaries of a flexible two-dimensional heated panel subjected to an impinging oblique shock are considered using theoretical analysis and numerical computations, respectively. The von-Karman large deflection theory of isotropic flat plates is used to account for the geometrical nonlinearity of the heated panel, and local first-order piston theory is employed in the region before and after shock waves to estimate the aerodynamic pressure. The coupled partial differential governing equations, according to the Hamilton principle, are established with thermal effect based on quasi-steady thermal stress theory.The Galerkin discrete method is employed to truncate the partial differential equations into a set of ordinary differential equations, which are then solved by the fourth-order Runge-Kutta numerical integration method. Lyapunov indirect method is applied to evaluate the stability of the heated panel. The results show that a new aeroelastic instability（distinct from regular panel flutter） arises from the complex interaction of the incident and reflected wave system with the panel flexural modes and thermal loads. What＇s more, stability of the panel is reduced in the presence of the oblique shock. In other words, the heated panel becomes aeroelastically unstable at relatively small flight aerodynamic pressure.展开更多
The main objective of this paper is to propose a newly developed ocean Significant Wave Height (SWH) retrieval method from Envisat Advanced Synthetic Aperture Radar (ASAR) imagery. A series of wave mode imagery from J...The main objective of this paper is to propose a newly developed ocean Significant Wave Height (SWH) retrieval method from Envisat Advanced Synthetic Aperture Radar (ASAR) imagery. A series of wave mode imagery from January, April and May of 2011 are collocated with ERA-Interim reanalysis SWH data. Based on the matched datasets, a simplified empirical relationship between 22 types of SAR imagery parameters and SWH products is developed with the Genetic Algorithms Partial Least-Squares (GA-PLS) model. Two major features of the backscattering coefficient σ0 and the frequency parameter S10 are chosen as the optimal training feature subset of SWH retrieval by using cross validation. In addition, we also present a comparison of the retrieval results of the simplified empirical relationship with the collocated ERA-Interim data. The results show that the assessment index of the correlation coefficient, the bias, the root-mean-square error of cross validation (RMSECV) and the scattering index (SI) are 0.78, 0.07 m, 0.76 m and 0.5, respectively. In addition, the comparison of the retrieved SWH data between our simplifying model and the Jason-2 radar altimeter data is proposed in our study. Moreover, we also make a comparison of the retrieval of SWH data between our developed model and the well- known CWAVE_ENV model. The results show that satisfying retrieval results are acquired in the low-moderate sea state, but major bias appears in the high sea state, especially for SWH>5 m.展开更多
Methyltransferase like 13(METTL13),a kind of methyltransferase,is implicated in protein binding and synthesis.The upregulation of METTL13 has been reported in a variety of tumors.However,little was known about its pot...Methyltransferase like 13(METTL13),a kind of methyltransferase,is implicated in protein binding and synthesis.The upregulation of METTL13 has been reported in a variety of tumors.However,little was known about its potential function in head and neck squamous cell carcinoma(HNSCC)so far.In this study,we found that METTL13 was significantly upregulated in HNSCC at both mRNA and protein level.Increased METTL13 was negatively associated with clinical prognosis.And METTL13 markedly affected HNSCC cellular phenotypes in vivo and vitro.Further mechanism study revealed that METTL13 could regulate EMT signaling pathway by mediating enhancing translation efficiency of Snail,the key transcription factor in EMT,hence regulating the progression of EMT.Furthermore,Snail was verified to mediate METTL13-induced HNSCC cell malignant phenotypes.Altogether,our study had revealed the oncogenic role of METTL13 in HNSCC,and provided a potential therapeutic strategy.展开更多
Existing studies have underscored the pivotal role of N-acetyltransferase 10(NAT10) in various cancers. However, the outcomes of protein-protein interactions between NAT10 and its protein partners in head and neck squ...Existing studies have underscored the pivotal role of N-acetyltransferase 10(NAT10) in various cancers. However, the outcomes of protein-protein interactions between NAT10 and its protein partners in head and neck squamous cell carcinoma(HNSCC) remain unexplored. In this study, we identified a significant upregulation of RNA-binding protein with serine-rich domain 1(RNPS1) in HNSCC, where RNPS1 inhibits the ubiquitination degradation of NAT10 by E3 ubiquitin ligase, zinc finger SWIM domain-containing protein 6(ZSWIM6), through direct protein interaction, thereby promoting high NAT10 expression in HNSCC. This upregulated NAT10 stability mediates the enhancement of specific tRNA ac^(4)C modifications, subsequently boosting the translation process of genes involved in pathways such as IL-6 signaling, IL-8 signaling, and PTEN signaling that play roles in regulating HNSCC malignant progression, ultimately influencing the survival and prognosis of HNSCC patients. Additionally, we pioneered the development of TRMC-seq, leading to the discovery of novel t RNA-ac^(4)C modification sites, thereby providing a potent sequencing tool for tRNAac^(4)C research. Our findings expand the repertoire of tRNA ac^(4)C modifications and identify a role of tRNA ac^(4)C in the regulation of mRNA translation in HNSCC.展开更多
In this paper,the east ore section of the Pulang porphyry copper deposit is selected as the research object.The micro-thermometer and laser Raman spectroscopic technique are utilized to study the parameters of ore-for...In this paper,the east ore section of the Pulang porphyry copper deposit is selected as the research object.The micro-thermometer and laser Raman spectroscopic technique are utilized to study the parameters of ore-forming fluids such as pressure,temperature,and compositions.In the meantime,the fractal models,including the perimeter-area(P-A)model and number-size(N-S)model,are introduced to quantify the shape of fluid inclusions,and distinguish the stages of ore-forming fluids,respectively.The results show that the types of fluid inclusions are diversified,namely two-phase liquid-rich type,two-phase vapor-rich type,three-phase CO2-rich type,three-phase halite-bearing type and pure liquid type.The fluids of main mineralization stage are characterized by medium-high temperature(170.2–421.4°C),medium-high salinity(9.3 wt.%–33.3 wt.%),and low density(0.73–1.06 g/cm3).With the migration and evolution,the temperature,salinity,and pressure of ore-forming fluids gradually decrease,while the density of fluids increases.The liquid-phase compositions mainly include H2O,and the vapor-phase compositions consist of H2O,CH4,N2,and CO2,indicating the characteristics of reducing fluids and the mixing of atmospheric precipitation.In general,the characteristics of ore-forming fluids in the east ore section are similar to those of the first mining area,suggesting that the ore-forming fluids in the east ore section may not migrate from the first mining area.And the east ore section may be a relatively independent metallogenic system.Moreover,the fractal analysis results demonstrate that the shape of fluid inclusions formed in the same hydrothermal activity features self-similarity.The DAPvalues of fluid inclusions in B veins,ED veins,andD veins are 1.04,1.06 and 1.10,respectively,showing a gradually increasing trend from the main stage to the late stage of mineralization.Meanwhile,the shape of fluid inclusions ranging from B veins to D veins becomes increasingly irregular.It also reveals that the homogenization temperature satisfies fractal distribution with four scale-invariant intervals,suggesting that all B veins,ED veins,and D veins have experienced at least four hydrothermal activities.Compared with histogram,the N-S fractal model is able to describe the distribution characteristics of the ore-forming fluids’homogenization temperature more precisely.Therefore,it presents a potential tool for the stage division of ore-forming fluids.This research provides information about the characteristics of ore-forming fluids in the east ore section of the Pulang porphyry copper deposit,which is beneficial for further exploration in this region,and the extension of the application of fractal models in the study of fluid inclusions.However,further testing of fractal models on the fluid inclusion study is warranted to fully determine the universality.展开更多
Non-blind audio bandwidth extension is a standard technique within contemporary audio codecs to efficiently code audio signals at low bitrates. In existing methods, in most cases high frequencies signal is usually gen...Non-blind audio bandwidth extension is a standard technique within contemporary audio codecs to efficiently code audio signals at low bitrates. In existing methods, in most cases high frequencies signal is usually generated by a duplication of the corresponding low frequencies and some parameters of high frequencies. However, the perception quality of coding will significantly degrade if the correlation between high frequencies and low frequencies becomes weak. In this paper, we quantitatively analyse the correlation via computing mutual information value. The analysis results show the correlation also exists in low frequency signal of the context dependent frames besides the current frame. In order to improve the perception quality of coding, we propose a novel method of high frequency coarse spectrum generation to improve the conventional replication method. In the proposed method, the coarse high frequency spectrums are generated by a nonlinear mapping model using deep recurrent neural network. The experiments confirm that the proposed method shows better performance than the reference methods.展开更多
Object-based audio coding is the main technique of audio scene coding. It can effectively reconstruct each object trajectory, besides provide sufficient flexibility for personalized audio scene reconstruction. So more...Object-based audio coding is the main technique of audio scene coding. It can effectively reconstruct each object trajectory, besides provide sufficient flexibility for personalized audio scene reconstruction. So more and more attentions have been paid to the object-based audio coding. However, existing object-based techniques have poor sound quality because of low parameter frequency domain resolution. In order to achieve high quality audio object coding, we propose a new coding framework with introducing the non-negative matrix factorization(NMF) method. We extract object parameters with high resolution to improve sound quality, and apply NMF method to parameter coding to reduce the high bitrate caused by high resolution. And the experimental results have shown that the proposed framework can improve the coding quality by 25%, so it can provide a better solution to encode audio scene in a more flexible and higher quality way.展开更多
Aiming to investigate the impacts of n-octanol addition on the oxidation reactivity,morphology and graphitization of diesel exhaust particles,soot samples were collected from a four-cylinder turbocharged diesel engine...Aiming to investigate the impacts of n-octanol addition on the oxidation reactivity,morphology and graphitization of diesel exhaust particles,soot samples were collected from a four-cylinder turbocharged diesel engine fueled with D100(neat diesel fuel),DO15(85%diesel and 15%n-octanol,V/V)and DO30(70%diesel and 30%n-octanol,V/V).All tests were conducted at two engine speeds of 1370 and 2150 r/min under a fixed torque of 125 N·m.The soot properties were characterized by thermogravimetric analyzer(TGA),transmission electron microscopy(TEM)and Raman spectroscopy(RS).The higher volatile organic fraction content,lower soot oxidation temperatures and lower activation energy from TGA results indicated that both the increasing n-octanol concentration and engine speed enhanced the soot oxidation reactivity.Additionally,quantitative analysis of TEM images showed that the soot derived from DO30 had the smallest primary particle diameters and fractal dimension,followed by those of soot produced by DO15 and D100.The RS results demonstrated that the n-octanol addition and higher engine speed led to a larger D1-FWHM(D1-full width at half maximum),A_(D1)/A_(T)(area ratio of D1 band and the total spectral)and A_(D3)/A_(T)(area ratio of D3 band and the total spectral)as well as a smaller L_(a)(crystallite width),revealing a lower degree of graphitization.Furthermore,the correlations between characterization parameters of soot properties and reactivity were nonlinear.展开更多
Plants serve as rich repositories of diverse chemical compounds collectively referred to as specialized metabolites.These compounds are of importance for adaptive processes,including interactions with various microbes...Plants serve as rich repositories of diverse chemical compounds collectively referred to as specialized metabolites.These compounds are of importance for adaptive processes,including interactions with various microbes both beneficial and harmful.Considering microbes as bioreactors,the chemical diversity undergoes dynamic changes when root-derived specialized metabolites(RSMs)and microbes encounter each other in the rhizosphere.Recent advancements in sequencing techniques and molecular biology tools have not only accelerated the elucidation of biosynthetic pathways of RSMs but also unveiled the significance of RSMs in plant-microbe interactions.In this review,we provide a comprehensive description of the effects of RSMs on microbe assembly in the rhizosphere and the influence of corresponding microbial changes on plant health,incorporating the most up-to-date information available.Additionally,we highlight open questions that remain for a deeper understanding of and harnessing the potential of RSM-microbe interactions to enhance plant adaptation to the environment.Finally,we propose a pipeline for investigating the intricate associations between root exometabolites and the rhizomicrobiome.展开更多
Deviation model is an important model for through-flow analysis in axial compressors.Theoretical analysis in classical deviation models is developed under the assumption of onedimensional flow,which is controlled by t...Deviation model is an important model for through-flow analysis in axial compressors.Theoretical analysis in classical deviation models is developed under the assumption of onedimensional flow,which is controlled by the continuity equation.To consider three-dimensional characteristics in transonic flow,this study proposes an improved theoretical analysis method combining force analysis of the blade-to-blade flow with conventional analysis of the continuity equation.Influences of shock structures on transverse force,streamwise velocity and streamline curvature in the blade-to-blade flow are analyzed,and support the analytical modelling of density flow ratio between inlet and outlet conditions.Thus,a novel deviation model for transonic stages in axial compressors is proposed in this paper.The empirical coefficients are corrected based on the experimental data of a linear cascade,and the prediction accuracy is validated with the experimental data of a three-stage transonic compressor.The novel model provides accurate predictions for meridional flow fields at the design point and performance curves at design speed,and shows obvious improvements on classical models by Carter and C¸etin.展开更多
The interaction between an elastic structure and electrodynamic shakers commonly exists in Ground Flutter Simulation Tests(GFST)with multi-point excitations,causing a considerable discrepancy between the practical exc...The interaction between an elastic structure and electrodynamic shakers commonly exists in Ground Flutter Simulation Tests(GFST)with multi-point excitations,causing a considerable discrepancy between the practical excitation forces and desired ones.To investigate the excitation force characteristics on a cantilever beam excited by a voltage-sourced electrodynamic shaker,the coupled shaker-beam system is modeled to derive the excitation force formula using Hamilton’s principle and Galerkin’s approach.Simulation results using the multi-mode beam model coupled with the shaker model are in good agreement with experimental results,verifying that the proposed multi-mode method can accurately predict the excitation force.Furthermore,parametric studies show that the influence of system parameters on the excitation force is related to the shaker’s operating mode.Unlike in current mode of shaker,when the beam resonant frequency approaches the suspension frequency of shaker armature,the variation of excitation force amplitude in voltage mode is no longer minimal.Meanwhile,if the exciting point in the GFST is located far away from the modal node,it is essential to compensate the force because the accuracy of tests can be reduced dramatically.The coupled shaker-beam model proposed in this paper can provide the basis for compensation measures.展开更多
基金supported by the National Science and Tech-nology Major Project of China(Nos.2017-II-0007-0021 and J2019-II-0017-0038)。
文摘Aerodynamic performances of axial compressors are significantly affected by variation of Reynolds number in aero-engines.In the design and analysis of compressors,previous correction methods for cascades and stages have difficulties in predicting comprehensively Reynolds number effects on airfoils,matching and characteristics curves.This study proposes Re-correction models for loss,deviation angle and endwall blockage based on classical theories and cascade tests,and loss and deviation models show good agreement in test data of NACA65 and C4 cascades.Throughflow method considering Reynolds number effects is developed by integrating the correction models into a verified Streamline Curvature(SLC)tool.A three-stage axial compressor is investigated through SLC and CFD methods from design Reynolds number(Red=2106)to low Re=4104,and the numerical methods are validated with test data of characteristic curves and spanwise distributions at Red.With Re reduction,SLC method with correction models well predicts variation in overall performances compared with CFD calculations and Wassell's model.Streamwise and spanwise matching such as total pressure and loss distributions in SLC predictions are basically consistent with those in CFD results at near-stall points under design and low Reynolds numbers.SLC and CFD methods share similar detections of stall risks in the third stage(Stg3),and their analyses of diffusion processes deviate to some extent due to different predictions in separated endwall flow.The correction models can be adopted to consider Reynolds number effects in through-flow design and analysis of axial compressors.
基金Supported by the National Key Research and Development Program of China(No.2021YFB3901304)the Shandong Provincial Natural Science Foundation(No.ZR2024QD054)+2 种基金the National Key Research and Development Program of China(No.2019YFA0606702)the National Natural Science Foundation of China(Nos.41906157,42306194,42306195)the Oceanographic Data Center,Chinese Academy of Sciences and the platform of Sino-Indonesian Joint Laboratory for Marine Sciences(SIMS)。
文摘Internal solitary waves(ISWs)are an essential dynamic process in the ocean due to their large amplitude and long propagation distance.Traditional satellite observations provide only twodimensional observations of ocean signatures induced by ISWs.The Surface Water and Ocean Topography(SWOT)satellite has drawn significant attention due to its high resolution and threedimensional observation capabilities.SWOT can generate high-precision three-dimensional sea surface topography,capture sea surface undulations,and reveal ISW-related surface oscillations,thus offering a new perspective for studying ISWs.We collected 43 SWOT observations with clear ISW signatures in the Lombok Strait from August 2023 to June 2024.Based on collected data,the ISW imaging characteristics and distributions were analyzed,and the ISW-related sea level anomaly(SLA)data were measured by the SWOT to calculate the ISW amplitude and reveal the amplitude variations during the propagation along the wave crest.The ISW amplitudes generally range between 10 and 100 m,with most ISW amplitudes between 20 and 40 m.By analyzing two consecutive generated ISW packets,we identified the spreading effect along ISW wave crests,which manifests as ISW amplitude decrease with increase in propagation distance,and the amplitude distribution is non-uniform along the wave crest.Further analysis of the propagation paths of the maximum amplitude of ISW moving northward through the Lombok Strait revealed that these maxima are predominantly oriented in northeast direction.Finally,the relationship between the amplitude of ISW and the resulting SLA was analyzed.The Pearson correlation coefficient between these two variables is as high as 0.90,which suggests a strong positive correlation between amplitude and SLA.Furthermore,this relationship is closely related to the water depth,indicating that the three-dimensional sea surface observations provided by SWOT offer crucial observational data for the inversion of amplitudes of ISW.
基金supported by the Strategic Priority Program of the Chinese Academy of Sciences(XDB0470303)the National Key R&D Program of China(2022YFB4600102and 2023YFE0209900)+4 种基金the National Natural Science Foundation of China(52175201 and 51935012)the science and technology projects of Gansu province(22JR5RA093,24JRRA044,24YFFA014 and 24ZDGA014)the Innovation and Entrepreneurship Team Project of YEDA(2021TD007)the special supporting project for provincial leading talents of Yantaithe Taishan Scholars Program。
文摘Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on traditional thermal processing or direct ink writing three-dimensional(3D)printing.These methods are not conducive to manufacturing complex structures and present challenges such as time inefficiency,poor accuracy,and the necessity of multiple steps,significantly limiting SR applications.In this study,we developed an SR-based ink suitable for vat photopolymerization 3D printing using a multi-thiol monomer.This ink enables the one-step fabrication of complex architectures with high printing resolution at the micrometer scale,providing excellent mechanical strength and superior chemical stability.Specifically,the optimized 3D printing SR-20 exhibits a tensile stress of 1.96 MPa,an elongation at break of 487.9%,and an elastic modulus of 225.4 kPa.Additionally,the 3D-printed SR samples can withstand various solvents(acetone,toluene,and tetrahydrofuran)and endure temperatures ranging from-50℃ to 180℃,demonstrating superior stability.As a emonstration of the application,we successfully fabricated a series of SR-based soft pneumatic actuators and grippers in a single step with this technology,allowing for free assembly for the first time.This ultraviolet-curable SR,with high printing resolution and exceptional stability performance,has significant potential to enhance the capabilities of 3D printing for applications in soft actuators,robotics,flexible electronics,and medical devices.
基金supported partially by the National Key Research and Development Program of China(No.2023YFF1303901)the National Natural Science Foundation of China(Nos.32171789,12411530088,and 32371654)the Joint Open Funded Project of State Key Laboratory of Geo-Information Engineering and Key Laboratory of the Ministry of Natural Resources for Surveying and Mapping Science and Geo-spatial Information Technology(No.2022-02-02).
文摘Unmanned aerial vehicle laser scanning(ULS)and terrestrial laser scanning(TLS)systems are effective ways to capture forest structures from top and side views,respectively.The registration of TLS and ULS data is a prerequisite for a comprehensive forest structure representation.Conventional registration methods based on geometric features(e.g.,points,lines,and planes)are likely to fail due to the irregular natural point distributions of forest point clouds.Currently,automatic registration methods for forest point clouds typically rely on tree attributes(such as tree position and stem diameter).However,these methods are often unsuitable for forests with diverse compositions,complex terrains,irregular tree layouts,and insufficient common trees.In this study,an automated method is proposed to register ULS and TLS forest point clouds using ground points as registration primitives,which operates independently of tree attribute extraction and is estimated to reduce processing time by over 50%.A new evaluation method for registration accuracy evaluation is proposed,where transformation parameters from each TLS scan to the ULS obtained by the proposed registration algorithm are used to derive transformation parameters between TLS scans,which are then compared to reference parameters obtained using artificial spherical targets.Conventional ULS-TLS registration evaluation methods mostly rely on the manual corresponding points selection that is subject to inherent subjective errors,or control points in both TLS and ULS data that are difficult to collect.The proposed method presents an objective and accurate solution for ULS-TLS registration accuracy evaluation that effectively eliminates these limitations.The proposed method was tested on 12 plots with diverse stem densities,tree species,and altitudes located in a mountain forest.A total of 124 TLS scans were successfully registered to ULS data.The registration accuracy was assessed using both the conventional evaluation method and the proposed new evaluation method,with average rotation errors of 2.03 and 2.06 mrad,and average translation errors of 7.63 and 6.51 cm,respectively.The registration accuracies demonstrate that the proposed algorithm effectively and accurately registers TLS to ULS point clouds.
基金supported by the National Natural Science Foundation of China (No.22106154).
文摘Personal care products(PCPs)are a class of emerging pollutants that have attracted public concern owing to their harmful effects on humans and the environment.Biomonitoring data is valuable for insight the levels of PCPs in the human body and can be crucial for identifying potential health hazards.To gain a better understanding of timely exposure profiles and health risk of reproductive-age population to PCPs,we determined six parabens,six benzophenone-type ultraviolet filters,and three disinfectants in 256 urine samples collected from young adults aged 18-44 years in Beijing,China.The urinary levels of benzophenone-3(BP-3)and 4-hydroxybenzophenone(4-OHBP)were significantly higher in summer compared to winter,suggesting these compounds have different seasonal usage patterns.Moreover,the total concentration of 15 PCPs in female was 430 ng/mL,approximately two times higher than that in male.P-chloro-m-xylenol(PCMX),as a new type of antibacterial agent,has the greatest level among all target analytes,indicating the increasingly use of this antibacterial alternative recently.Five potential influencing factors that lead to the elevated exposure level of PCPs were identified.Over 19%of the target population had a high hazard index value(greater than 1)which was attributed to exposure to propyl paraben(PrP),benzophenone-1(BP-1),BP-3 and PCMX,indicating that PCPs may pose a relatively high exposure risk at environmental levels that should be a cause for concern.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC3003205)the Chengdu University of Technology Postgraduate Innovative Cultivation Program(Grant No.10800-000510-01-022)+1 种基金the Sichuan Science and Technology Program(Grant No.2025ZNSFSC1206)the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(Grant No.SKLGP2023Z026).
文摘Research on the application of machine learning(ML)models to landslide susceptibility assessments has gained popularity in recent years,with a focus primarily on topographic factors derived from digital elevation models(DEMs).However,few studies have focused on the explanatory effects of these factors on different models,i.e.whether DEM-based factors affect different models in the same way.This study investigated whether different ML models could yield consistent interpretations of DEM-based factors using explanatory algorithms.Six ML models,including a support vector machine,a neural network,extreme gradient boosting,a random forest,linear regression,and K-nearest neighbors,were trained and evaluated on five geospatial datasets derived from different DEMs.Each dataset contained eight DEM-based and six non-DEM-based factors from 8912 landslide samples.Model performance was assessed using accuracy,precision,recall rate,F1-score,kappa coefficient,and receiver operating characteristic curves.Explanatory analyses,including Shapley additive explanations and partial dependence plots,were also employed to investigate the effects of topographic factors on landslide susceptibility.The results indicate that DEM-based factors consistently influenced different ML models across the datasets.Furthermore,tree-based models outperformed the other models in almost all datasets,while the most suitable DEMs were obtained from Copernicus and TanDEM-X.In addition,the concave surface without potholes on steep slopes are ideal topographic conditions for landslide formation in the study area.This study can benefit the wider landslide research community by clarifying how topographic factors affect ML models.
基金supported by the National Key Research and Development Program of China(No.2022YFC3704200)the National Natural Science Foundation of China(No.52306128)+5 种基金the Major Program of Science and Technology of Hainan Province,China(No.ZDKJ202007)the Innovation Platform for Academicians of Hainan Province(No.YSPTZX202205)the Youth Innovation Foundation of Hainan Research Academy of Environmental Sciences,China(No.QNCX2021002)the Central Guiding Local Science and Technology Development Fund Projects(No.236Z4001G)the Natural Science Basic Research Program of Shaanxi(No.2023-JC-QN-0517)the support from Energy Foundation China.
文摘This paper presents an air quality simulation model that incorporates shipping activities and weather conditions,with a case study of Hainan Island to examine the impact of ship emissions on air quality.The findings reveal that the density of automatic identification system(AIS)signals is particularly high in the southern coastal regions.The results showed that the annual ship emissions recorded the highest density of 896.7 tons/0.01°,49.8 tons/0.01°,1139.7 tons/0.01°,and 122,000 tons/0.01°for sulfur oxides(SO_(x)),particulate matter(PM),nitrogen oxides(NOx),and carbon dioxide(CO_(2)),respectively.Furthermore,the partial distributions of these emissions were not significantly affected by the seasons.Ships within twelve nautical miles of Hainan coastlines emit approximately 2817.7 tons of SO_(x),14,686.4 tons of NO_(x),630.4 tons of PM_(2.5),and 416.9 tons of hydrocarbons(HC)annually.These emissions are primarily concentrated in the sea areas surrounding the ports of Haikou,Yangpu,Basuo,and Sanya.Ships manufactured between 2000 and 2010 have contributed significantly to air pollution,with SO_(x) and HC emissions accounting for approximately 51%and 56% of total emissions,respectively.However,for shipsmanufactured after 2016,these proportions have dropped to approximately 10%.In terms of air pollutants fromship emissions in Hainan Island,the spatial distribution of their contributions is significantly uneven.The impact of PM2.5 differs significantly depending on the season,with the concentrations being substantially higher during Spring.However,the proportions of O3 and other pollutants do not vary significantly,except during Spring.
基金supported by the National Natural Science Foundation of China (No. 11732013)
文摘The critical conditions for aeroelastic stability and the stability boundaries of a flexible two-dimensional heated panel subjected to an impinging oblique shock are considered using theoretical analysis and numerical computations, respectively. The von-Karman large deflection theory of isotropic flat plates is used to account for the geometrical nonlinearity of the heated panel, and local first-order piston theory is employed in the region before and after shock waves to estimate the aerodynamic pressure. The coupled partial differential governing equations, according to the Hamilton principle, are established with thermal effect based on quasi-steady thermal stress theory.The Galerkin discrete method is employed to truncate the partial differential equations into a set of ordinary differential equations, which are then solved by the fourth-order Runge-Kutta numerical integration method. Lyapunov indirect method is applied to evaluate the stability of the heated panel. The results show that a new aeroelastic instability（distinct from regular panel flutter） arises from the complex interaction of the incident and reflected wave system with the panel flexural modes and thermal loads. What＇s more, stability of the panel is reduced in the presence of the oblique shock. In other words, the heated panel becomes aeroelastically unstable at relatively small flight aerodynamic pressure.
基金The National Science Foundation for Young Scientists of China under contract No.61501130the National Key Research and Development Program of China under contract Nos 2016YFB0502504 and 2016YFB0502500the National Natural Science Foundation of China under contract Nos 41431174,61471358 and 41401427
文摘The main objective of this paper is to propose a newly developed ocean Significant Wave Height (SWH) retrieval method from Envisat Advanced Synthetic Aperture Radar (ASAR) imagery. A series of wave mode imagery from January, April and May of 2011 are collocated with ERA-Interim reanalysis SWH data. Based on the matched datasets, a simplified empirical relationship between 22 types of SAR imagery parameters and SWH products is developed with the Genetic Algorithms Partial Least-Squares (GA-PLS) model. Two major features of the backscattering coefficient σ0 and the frequency parameter S10 are chosen as the optimal training feature subset of SWH retrieval by using cross validation. In addition, we also present a comparison of the retrieval results of the simplified empirical relationship with the collocated ERA-Interim data. The results show that the assessment index of the correlation coefficient, the bias, the root-mean-square error of cross validation (RMSECV) and the scattering index (SI) are 0.78, 0.07 m, 0.76 m and 0.5, respectively. In addition, the comparison of the retrieved SWH data between our simplifying model and the Jason-2 radar altimeter data is proposed in our study. Moreover, we also make a comparison of the retrieval of SWH data between our developed model and the well- known CWAVE_ENV model. The results show that satisfying retrieval results are acquired in the low-moderate sea state, but major bias appears in the high sea state, especially for SWH>5 m.
基金supported by grants from the National Natural Science Foundation of China(81872409)Natural Science Foundation of Guangdong Province(2018A030313610)+1 种基金the Open Funding of the State Key Laboratory of Oral Diseases(SKLOD2021OF02)Guangdong Basic and Applied Basic Research Foundation(2019A1515110110)。
文摘Methyltransferase like 13(METTL13),a kind of methyltransferase,is implicated in protein binding and synthesis.The upregulation of METTL13 has been reported in a variety of tumors.However,little was known about its potential function in head and neck squamous cell carcinoma(HNSCC)so far.In this study,we found that METTL13 was significantly upregulated in HNSCC at both mRNA and protein level.Increased METTL13 was negatively associated with clinical prognosis.And METTL13 markedly affected HNSCC cellular phenotypes in vivo and vitro.Further mechanism study revealed that METTL13 could regulate EMT signaling pathway by mediating enhancing translation efficiency of Snail,the key transcription factor in EMT,hence regulating the progression of EMT.Furthermore,Snail was verified to mediate METTL13-induced HNSCC cell malignant phenotypes.Altogether,our study had revealed the oncogenic role of METTL13 in HNSCC,and provided a potential therapeutic strategy.
基金supported by the National Natural Science Foundation of China(82173362 and 81872409)the Guangdong Basic and Applied Basic Research Foundation(2019A1515110110)。
文摘Existing studies have underscored the pivotal role of N-acetyltransferase 10(NAT10) in various cancers. However, the outcomes of protein-protein interactions between NAT10 and its protein partners in head and neck squamous cell carcinoma(HNSCC) remain unexplored. In this study, we identified a significant upregulation of RNA-binding protein with serine-rich domain 1(RNPS1) in HNSCC, where RNPS1 inhibits the ubiquitination degradation of NAT10 by E3 ubiquitin ligase, zinc finger SWIM domain-containing protein 6(ZSWIM6), through direct protein interaction, thereby promoting high NAT10 expression in HNSCC. This upregulated NAT10 stability mediates the enhancement of specific tRNA ac^(4)C modifications, subsequently boosting the translation process of genes involved in pathways such as IL-6 signaling, IL-8 signaling, and PTEN signaling that play roles in regulating HNSCC malignant progression, ultimately influencing the survival and prognosis of HNSCC patients. Additionally, we pioneered the development of TRMC-seq, leading to the discovery of novel t RNA-ac^(4)C modification sites, thereby providing a potent sequencing tool for tRNAac^(4)C research. Our findings expand the repertoire of tRNA ac^(4)C modifications and identify a role of tRNA ac^(4)C in the regulation of mRNA translation in HNSCC.
基金supported by the National Key R&D Program of China(No.2016YFC0600508)the Open Fund of the Research Center for Petrogenesis and Mineralization of Granitoid Rocks,China Geological Survey(No.PMGR202011)China Geological Survey(No.DD20190385)。
文摘In this paper,the east ore section of the Pulang porphyry copper deposit is selected as the research object.The micro-thermometer and laser Raman spectroscopic technique are utilized to study the parameters of ore-forming fluids such as pressure,temperature,and compositions.In the meantime,the fractal models,including the perimeter-area(P-A)model and number-size(N-S)model,are introduced to quantify the shape of fluid inclusions,and distinguish the stages of ore-forming fluids,respectively.The results show that the types of fluid inclusions are diversified,namely two-phase liquid-rich type,two-phase vapor-rich type,three-phase CO2-rich type,three-phase halite-bearing type and pure liquid type.The fluids of main mineralization stage are characterized by medium-high temperature(170.2–421.4°C),medium-high salinity(9.3 wt.%–33.3 wt.%),and low density(0.73–1.06 g/cm3).With the migration and evolution,the temperature,salinity,and pressure of ore-forming fluids gradually decrease,while the density of fluids increases.The liquid-phase compositions mainly include H2O,and the vapor-phase compositions consist of H2O,CH4,N2,and CO2,indicating the characteristics of reducing fluids and the mixing of atmospheric precipitation.In general,the characteristics of ore-forming fluids in the east ore section are similar to those of the first mining area,suggesting that the ore-forming fluids in the east ore section may not migrate from the first mining area.And the east ore section may be a relatively independent metallogenic system.Moreover,the fractal analysis results demonstrate that the shape of fluid inclusions formed in the same hydrothermal activity features self-similarity.The DAPvalues of fluid inclusions in B veins,ED veins,andD veins are 1.04,1.06 and 1.10,respectively,showing a gradually increasing trend from the main stage to the late stage of mineralization.Meanwhile,the shape of fluid inclusions ranging from B veins to D veins becomes increasingly irregular.It also reveals that the homogenization temperature satisfies fractal distribution with four scale-invariant intervals,suggesting that all B veins,ED veins,and D veins have experienced at least four hydrothermal activities.Compared with histogram,the N-S fractal model is able to describe the distribution characteristics of the ore-forming fluids’homogenization temperature more precisely.Therefore,it presents a potential tool for the stage division of ore-forming fluids.This research provides information about the characteristics of ore-forming fluids in the east ore section of the Pulang porphyry copper deposit,which is beneficial for further exploration in this region,and the extension of the application of fractal models in the study of fluid inclusions.However,further testing of fractal models on the fluid inclusion study is warranted to fully determine the universality.
基金supported by the National Natural Science Foundation of China under Grant No. 61762005, 61231015, 61671335, 61702472, 61701194, 61761044, 61471271National High Technology Research and Development Program of China (863 Program) under Grant No. 2015AA016306+2 种基金 Hubei Province Technological Innovation Major Project under Grant No. 2016AAA015the Science Project of Education Department of Jiangxi Province under No. GJJ150585The Opening Project of Collaborative Innovation Center for Economics Crime Investigation and Prevention Technology, Jiangxi Province, under Grant No. JXJZXTCX-025
文摘Non-blind audio bandwidth extension is a standard technique within contemporary audio codecs to efficiently code audio signals at low bitrates. In existing methods, in most cases high frequencies signal is usually generated by a duplication of the corresponding low frequencies and some parameters of high frequencies. However, the perception quality of coding will significantly degrade if the correlation between high frequencies and low frequencies becomes weak. In this paper, we quantitatively analyse the correlation via computing mutual information value. The analysis results show the correlation also exists in low frequency signal of the context dependent frames besides the current frame. In order to improve the perception quality of coding, we propose a novel method of high frequency coarse spectrum generation to improve the conventional replication method. In the proposed method, the coarse high frequency spectrums are generated by a nonlinear mapping model using deep recurrent neural network. The experiments confirm that the proposed method shows better performance than the reference methods.
基金supported by National High Technology Research and Development Program of China (863 Program) (No.2015AA016306)National Nature Science Foundation of China (No.61231015)National Nature Science Foundation of China (No.61671335)
文摘Object-based audio coding is the main technique of audio scene coding. It can effectively reconstruct each object trajectory, besides provide sufficient flexibility for personalized audio scene reconstruction. So more and more attentions have been paid to the object-based audio coding. However, existing object-based techniques have poor sound quality because of low parameter frequency domain resolution. In order to achieve high quality audio object coding, we propose a new coding framework with introducing the non-negative matrix factorization(NMF) method. We extract object parameters with high resolution to improve sound quality, and apply NMF method to parameter coding to reduce the high bitrate caused by high resolution. And the experimental results have shown that the proposed framework can improve the coding quality by 25%, so it can provide a better solution to encode audio scene in a more flexible and higher quality way.
基金supported by National Natural Science Foundation of China(No.51776162)Natural Science Basic Research Program of Shaanxi(No.2020JM-044)Fundamental Research Funds for the Central Universities(No.xzy032019002)。
文摘Aiming to investigate the impacts of n-octanol addition on the oxidation reactivity,morphology and graphitization of diesel exhaust particles,soot samples were collected from a four-cylinder turbocharged diesel engine fueled with D100(neat diesel fuel),DO15(85%diesel and 15%n-octanol,V/V)and DO30(70%diesel and 30%n-octanol,V/V).All tests were conducted at two engine speeds of 1370 and 2150 r/min under a fixed torque of 125 N·m.The soot properties were characterized by thermogravimetric analyzer(TGA),transmission electron microscopy(TEM)and Raman spectroscopy(RS).The higher volatile organic fraction content,lower soot oxidation temperatures and lower activation energy from TGA results indicated that both the increasing n-octanol concentration and engine speed enhanced the soot oxidation reactivity.Additionally,quantitative analysis of TEM images showed that the soot derived from DO30 had the smallest primary particle diameters and fractal dimension,followed by those of soot produced by DO15 and D100.The RS results demonstrated that the n-octanol addition and higher engine speed led to a larger D1-FWHM(D1-full width at half maximum),A_(D1)/A_(T)(area ratio of D1 band and the total spectral)and A_(D3)/A_(T)(area ratio of D3 band and the total spectral)as well as a smaller L_(a)(crystallite width),revealing a lower degree of graphitization.Furthermore,the correlations between characterization parameters of soot properties and reactivity were nonlinear.
基金National Key Research and Development Program of China(2018YFA0900603 to G.W.and 2022YFF1001800 to Y.B.)the National Natural Science Foundation of China(grant No.32000232)to X.W.the State Key Laboratory of Plant Genomics of China(SKLPG2016A-13)to G.W.
文摘Plants serve as rich repositories of diverse chemical compounds collectively referred to as specialized metabolites.These compounds are of importance for adaptive processes,including interactions with various microbes both beneficial and harmful.Considering microbes as bioreactors,the chemical diversity undergoes dynamic changes when root-derived specialized metabolites(RSMs)and microbes encounter each other in the rhizosphere.Recent advancements in sequencing techniques and molecular biology tools have not only accelerated the elucidation of biosynthetic pathways of RSMs but also unveiled the significance of RSMs in plant-microbe interactions.In this review,we provide a comprehensive description of the effects of RSMs on microbe assembly in the rhizosphere and the influence of corresponding microbial changes on plant health,incorporating the most up-to-date information available.Additionally,we highlight open questions that remain for a deeper understanding of and harnessing the potential of RSM-microbe interactions to enhance plant adaptation to the environment.Finally,we propose a pipeline for investigating the intricate associations between root exometabolites and the rhizomicrobiome.
基金supported by the National Natural Science Foundation of China (No. 52176039)the National Science and Technology Major Project of China (No. 2017-Ⅱ-0007-0021)
文摘Deviation model is an important model for through-flow analysis in axial compressors.Theoretical analysis in classical deviation models is developed under the assumption of onedimensional flow,which is controlled by the continuity equation.To consider three-dimensional characteristics in transonic flow,this study proposes an improved theoretical analysis method combining force analysis of the blade-to-blade flow with conventional analysis of the continuity equation.Influences of shock structures on transverse force,streamwise velocity and streamline curvature in the blade-to-blade flow are analyzed,and support the analytical modelling of density flow ratio between inlet and outlet conditions.Thus,a novel deviation model for transonic stages in axial compressors is proposed in this paper.The empirical coefficients are corrected based on the experimental data of a linear cascade,and the prediction accuracy is validated with the experimental data of a three-stage transonic compressor.The novel model provides accurate predictions for meridional flow fields at the design point and performance curves at design speed,and shows obvious improvements on classical models by Carter and C¸etin.
基金co-supported by the Overseas Expertise Introduction Project for Discipline In-novation(111 Project,BP0719007)the National Natural Science Foundation of China(No.12002280)。
文摘The interaction between an elastic structure and electrodynamic shakers commonly exists in Ground Flutter Simulation Tests(GFST)with multi-point excitations,causing a considerable discrepancy between the practical excitation forces and desired ones.To investigate the excitation force characteristics on a cantilever beam excited by a voltage-sourced electrodynamic shaker,the coupled shaker-beam system is modeled to derive the excitation force formula using Hamilton’s principle and Galerkin’s approach.Simulation results using the multi-mode beam model coupled with the shaker model are in good agreement with experimental results,verifying that the proposed multi-mode method can accurately predict the excitation force.Furthermore,parametric studies show that the influence of system parameters on the excitation force is related to the shaker’s operating mode.Unlike in current mode of shaker,when the beam resonant frequency approaches the suspension frequency of shaker armature,the variation of excitation force amplitude in voltage mode is no longer minimal.Meanwhile,if the exciting point in the GFST is located far away from the modal node,it is essential to compensate the force because the accuracy of tests can be reduced dramatically.The coupled shaker-beam model proposed in this paper can provide the basis for compensation measures.
