Multicomponent Gd_(1−x)Sm_(x)Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)double perovskites are optimized for application in terms of chemical composi-tion and morphology for the use as oxygen electrodes in solid oxide cells.Structur...Multicomponent Gd_(1−x)Sm_(x)Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)double perovskites are optimized for application in terms of chemical composi-tion and morphology for the use as oxygen electrodes in solid oxide cells.Structural studies of other physicochemical properties are con-ducted on a series of materials obtained by the sol-gel method with different ratios of Gd and Sm cations.It is documented that changing the x value,and the resulting adjustment of the average ionic radius,have a significant impact on the crystal structure,stability,as well as on the total conductivity and thermomechanical properties of the materials,with the best results obtained for the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)composition.Oxygen electrodes are prepared using the selected compound,allowing to obtain low polarization resistance values,such as 0.086Ω·cm^(2)at 800℃.Systematic studies of electrocatalytic activity are conducted using La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(_(0.2))O_(3−δ)as the electrolyte for all electrodes,and Ce_(0.8)Gd_(0.2)O_(2−δ)electrolyte for the best performing Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes.The electrochemical data are analyzed using the distribution of relaxation times method.Also,the influence of the preparation method of the electrode material is in-ve`stigated using the electrospinning technique.Finally,the performance of the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes is tested in a Ni-YSZ(yttria-stabilized zirconia)anode-supported cell with a Ce_(0.8)Gd_(0.2)O_(2−δ)buffer layer,in the fuel cell and electrolyzer operating modes.With the electrospun electrode,a power density of 462 mW·cm^(−2)is obtained at 700℃,with a current density of ca.0.2 A·cm^(−2)at 1.3 V for the electrolysis at the same temperature,indicating better performance compared to the sol-gel-based electrode.展开更多
Laser-directed energy deposition(L-DED)is an advanced additive manufacturing technology primarily adopted in metal three-dimensional printing systems.The L-DED process is characterized by various defects,thus necessit...Laser-directed energy deposition(L-DED)is an advanced additive manufacturing technology primarily adopted in metal three-dimensional printing systems.The L-DED process is characterized by various defects,thus necessitating the extensive use of in-situ monitoring to enable real-time adjustments of process parameters by detecting molten-pool features.To address the challenge of accurately extracting the molten-pool morphology from an undetached spatter,an innovative monitoring method based on the U-Net(U-shaped network)is proposed herein.A lightweight architecture accelerates the processing speed,whereas an enhanced loss function incorporating weight maps augments the segmentation precision.The model performance is evaluated by comparing its segmentation accuracy and processing speed with those of the conventional U-Net,using the mean intersection over union(MIoU)as the segmentation metric.The improved model demonstrates superior segmentation accuracy at the interface between the molten pool and spatter,with a peak MIoU of 0.9798 achieved on the test set.Furthermore,this model processes each image in an extremely short time of 17.9 ms.Using this segmentation algorithm,the error in extracting the molten-pool width from single-track experiments is within 0.1 mm.The proposed method for monitoring the molten-pool morphology is suitable for deployment in online monitoring systems,thus providing a foundation for subsequent process-parameter regulation.展开更多
Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and memory.Kinesin-4 KIF21A helps organize the microtubule-actin network at th...Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and memory.Kinesin-4 KIF21A helps organize the microtubule-actin network at the cell cortex by interacting with KANK1;however,whether KIF21A modulates dendritic structure and function in neurons remains unknown.In this study,we found that KIF21A was distributed in a subset of dendritic spines,and that these KIF21A-positive spines were larger and more structurally plastic than KIF21A-negative spines.Furthermore,the interaction between KIF21A and KANK1 was found to be critical for dendritic spine morphogenesis and synaptic plasticity.Knockdown of either KIF21A or KANK1 inhibited dendritic spine morphogenesis and dendritic branching,and these deficits were fully rescued by coexpressing full-length KIF21A or KANK1,but not by proteins with mutations disrupting direct binding between KIF21A and KANK1 or binding between KANK1 and talin1.Knocking down KIF21A in the hippocampus of rats inhibited the amplitudes of long-term potentiation induced by high-frequency stimulation and negatively impacted the animals’cognitive abilities.Taken together,our findings demonstrate the function of KIF21A in modulating spine morphology and provide insight into its role in synaptic function.展开更多
Zinc oxide(ZnO)serves as a crucial functional semiconductor with a wide direct bandgap of approximately 3.37 eV.Solvothermal reaction is commonly used in the synthesis of ZnO micro/nanostructures,given its low cost,si...Zinc oxide(ZnO)serves as a crucial functional semiconductor with a wide direct bandgap of approximately 3.37 eV.Solvothermal reaction is commonly used in the synthesis of ZnO micro/nanostructures,given its low cost,simplicity,and easy implementation.Moreover,ZnO morphology engineering has become desirable through the alteration of minor conditions in the reaction process,particularly at room temperature.In this work,ZnO micro/nanostructures were synthesized in a solution by varying the amounts of the ammonia added at low temperatures(including room temperature).The formation of Zn^(2+)complexes by ammonia in the precursor regulated the reaction rate of the morphology engineering of ZnO,which resulted in various structures,such as nanoparticles,nanosheets,microflowers,and single crystals.Finally,the obtained ZnO was used in the optoelectronic application of ultraviolet detectors.展开更多
The preferential oxidation of CO(CO-PROX)reaction is a cost-effective method for eliminating trace amounts of CO from the fuel H2.Pt-based catalysts have been extensively studied for COPROX,with their activity influen...The preferential oxidation of CO(CO-PROX)reaction is a cost-effective method for eliminating trace amounts of CO from the fuel H2.Pt-based catalysts have been extensively studied for COPROX,with their activity influenced by the morphology of the support.Hydrothermal synthesis was employed to produce different morphologies ofγ-Al_(2)O_(3):flower-likeγ-Al_(2)O_(3)(f)exposing(110)crystal faces,sheet-likeγ-Al_(2)O_(3)(s)revealing(100)crystal faces,and rod-likeγ-Al_(2)O_(3)(r)displaying(111)crystal faces,followed by loading PtCo nanoparticles.The exposed crystal faces of the support impact the alloying degree of the PtCo nanoparticles,and an increase in the alloying degree correlates with enhanced catalyst reactivity.Pt_(3)Co intermetallic compounds were identified onγ-Al_(2)O_(3)(f)exposing(110)crystal faces,and PtCo/γ-Al_(2)O_(3)(f)showed high catalytic activity in the CO-PROX reaction,achieving 100%CO conversion across a broad temperature range of 50−225°C.In contrast,only partial alloying of PtCo was observed onγ-Al_(2)O_(3)(s).Furthermore,no alloying between Pt and Co occurred in PtCo/γ-Al_(2)O_(3)(r),resulting in a reaction rate at 50°C that was merely 11%of that of PtCo/γ-Al_(2)O_(3)(f).The formation of Pt3Co intermetallic compounds led to a more oxidized state of Pt,which significantly diminished the adsorption of CO on Pt and augmented the active oxygen species,thereby facilitating the selective oxidation of CO.展开更多
Harrat Lunayyir,a volcanic field in western Saudi Arabia,exhibits diverse geomorphological and topographical features shaped by volcanic,tectonic,and climatic processes.This study integrates field observations,remote ...Harrat Lunayyir,a volcanic field in western Saudi Arabia,exhibits diverse geomorphological and topographical features shaped by volcanic,tectonic,and climatic processes.This study integrates field observations,remote sensing,and GIS analysis to investigate the spatial distribution and relationships between volcanic landforms,lava flows,and topographical variation result obtained is a morphological classification of the cinder cones of Harrat Lunayyir,which can be sub-divided into four types:tephra rings,horseshoe-shaped volcanoes,multiple volcanoes and volcanoes without craters.All of these are monogenetic volcanoes,unlike central volcanoes(stratovolcanoes)which live for tens or hundreds of thousands of years and erupt numerous times.In Harrat Lunayyir,there is a clear dominance of arched horseshoe-shaped volcanoes(58)over ring-shaped cinder cones(10),A1_symmetric cones(circular,uniform cinder cones with a single crater)(32),A2_asymmetric cones(elongated,irregular cones and may feature one or more craters)(8),volcanoes without craters(55)and multiple volcanoes(20).The classification presented in this paper makes it possible to include all morphological types of volcanoes found in the region.This fact also renders the present classification a useful tool to apply in other,both insular and continental volcanic areas to eventually analyze and systematize the study of eruptive edifices with similar traits.Hence,this research will explore the standard physical volcanology literature so as to follow accepted definitions.展开更多
Cryptocaryon irritans is the parasite responsible for“white spot disease”in the yellowfin seabream Acanthopagrus latus,which has caused significant losses to the aquaculture industry.This experiment investigated the...Cryptocaryon irritans is the parasite responsible for“white spot disease”in the yellowfin seabream Acanthopagrus latus,which has caused significant losses to the aquaculture industry.This experiment investigated the changes in the morphology,transcriptome,and proteome of gill tissue in yellowfin seabream infected with C.irritans,aiming to provide foundational data for further understanding the pathogenic mechanisms and control measures against this parasite.The main findings were as follows,after C.irritans infection,the structure of gill tissue in yellowfin seabream was damaged,with microvessels ruptured,some cells proliferating,and large amounts of mucus infiltrating.Transcriptome analysis revealed a total of 4299 differentially expressed genes,with 2367 up-regulated and 1932down-regulated.Further bioinformatics analysis of all differentially expressed genes identified nine immune-related genes,cox-2,mcama,tbx21,dcn,tnfb,cd74a,illb,ppib,and cd4-1 in A.latus.The reliability of the transcriptome data was validated by real time q PCR,which showed the same trend as the RNA-seq results.Proteome analysis found365 differential proteins,with 180 proteins up-regulated and 185 proteins down-regulated.Bioinformatics analysis identified three immune-related proteins,Myll,Gapdh,and Actn3b.These findings indicated that C.irritans disrupted the structure of gill tissue,impeded gas exchange and led to asphyxiation and death in affected fish.Transcriptome and proteome analyses showed that the expression of immune-related genes and proteins in yellowfin seabream,involved not only inflammatory responses and the activation and migration of immune cells but also potentially participated in tissue repair and defense regulation.These findings highlighted the complex immune regulatory network in response to C.irritans infection,offering references for prevention and control of white spot disease in yellowfin seabream.展开更多
The East China Sea(ECS)off the Coast of Zhoushan Archipelago,Zhejiang(ECS-CZA)is home to abundant fishery resources and an important spawning,feeding,and nursing ground for a variety of fish species.Due to long-term o...The East China Sea(ECS)off the Coast of Zhoushan Archipelago,Zhejiang(ECS-CZA)is home to abundant fishery resources and an important spawning,feeding,and nursing ground for a variety of fish species.Due to long-term overfishing,the ichthyoplankton structure has been dramatically altered.Understanding the species composition and distribution of fish eggs and larvae is one of the most essential tasks to accurately regulate fishery resources and formulate effective management policies;however,little is known about the ichthyoplankton in this region.In this study,an integrated strategy of morphology identification(MI)and mitochondrial COI DNA barcoding was used to identify species of fish eggs and larvae collected from the ECSCZA.MI revealed 15 fish egg species belonging to 12 families and 12 fish larva species belonging to 12 families;in contrast,DNA barcoding altogether identified 30 species,including 18 fish egg species and 13 fish larva species.One species was shared between the egg and larva samples.Our study offers useful tools and critical scientific information for further understanding the diversity,distribution,and conservation management of various ichthyoplankton species in the marine environment.展开更多
This is a correction to:Isabela R R Moraes,Mariana Antunes,Laura S Lopez-Greco,Fernando Jose Zara,Antonio Leao Castilho,Functional reproductive morphology of the snapping shrimp genus Synalpheus Spence Bate,1888(Decap...This is a correction to:Isabela R R Moraes,Mariana Antunes,Laura S Lopez-Greco,Fernando Jose Zara,Antonio Leao Castilho,Functional reproductive morphology of the snapping shrimp genus Synalpheus Spence Bate,1888(Decapoda,Alpheidae),Current Zoology,2024,71,338-352;https:/doi.org/10.1093/cz/zoae053.展开更多
Dear Editor,The primary motor cortex,also known as MOp in rodents,F1,or M1 in primates[1],plays a crucial role in autonomous motor control.It is interconnected with other motor control structures such as the basal gan...Dear Editor,The primary motor cortex,also known as MOp in rodents,F1,or M1 in primates[1],plays a crucial role in autonomous motor control.It is interconnected with other motor control structures such as the basal ganglia,thalamus,and brainstem.Among these connections,the corticostriatal system plays a significant role in functions including action selection,motor control,sequence learning,and habit formation[2].展开更多
Morphology,the study of shapes or forms,when applied to tourism,emphasizes the multifarious spatial practices between morphological elements and tourism activities.However,existing literature on morphology in the cont...Morphology,the study of shapes or forms,when applied to tourism,emphasizes the multifarious spatial practices between morphological elements and tourism activities.However,existing literature on morphology in the context of tourism usually only focuses on a single or a limited number of study areas,overlooking common or even universal patterns across various tourism destinations.To address this gap,we utilize geospatial big data and present a case study on the morphology of 406“AAAAA”-rated scenic areas in China.A framework based on“points”,“lines”,“planes”,and“solids”was designed to systematically organize and analyze morphological elements across scenic areas.The findings provide valuable insights for tourism planning and development,such as the co-occurrence of dense road networks and fragmented landscapes within scenic areas,as well as the resourcecontext-influenced(cultural or natural)associations between morphological features and tourism indicators.This research provides valuable strategic guidance for more effective and informed tourism development while acknowledging the trade-offs between generalizability and local specificity.展开更多
The operation of cascade reservoirs in a watershed profoundly exerts river watersediment dynamics and topography evolution,and the terminal reservoir is the focus area for river and waterway management.This paper reve...The operation of cascade reservoirs in a watershed profoundly exerts river watersediment dynamics and topography evolution,and the terminal reservoir is the focus area for river and waterway management.This paper reveals the process and underlying factors of topography evolution and water level adjustment in the lower Hanjiang River under the action of cascade reservoirs.This study focused on the 263 km river channel downstream of the Xinglong Hydropower Conservancy Project on the Hanjiang River.Using measured flow,sediment,and topography data from 1977 to 2023,we analyzed the changing characteristics of riverbed scouring and deposition intensity,thalweg,and cross-sections.Additionally,we evaluated the response relationship between riverbed scouring and deposition intensity and factors such as sediment transport,runoff,and human activities.From 1977 to 2023,the low-water channel in the Xinglong-Estuary reaches showed a scouring and cutting tendency,and the riverbed slop initially decreased and then increased.The main cause of the riverbed scouring along the Xinglong-Estuary reaches was the reduced sediment load in the watershed,with waterway engineering having a slightly larger influence than runoff in the Xinglong-Xiantao reaches;by contrast,runoff exerted a more significant effect than both waterway engineering and the Yangtze River water level decline in the Xiantao-Estuary reaches.During the autumn flood season from 1983 to 2023,the water level differences between the Hanjiang and Yangtze Rivers at the same flow rate showed an increasing trend,leading to an increase in water surface slope,which intensified scouring forces and riverbed scouring.This study improves our understanding of the impacts of dam construction on river topographical evolution,water level changes,and deep‐water waterway resources.展开更多
This study aims to develop a high-precision and cost-efficient method for the threedimensional reconstruction of large particles in natural gravel and blasted rock fragments,utilizing Structure from Motion(SfM)and Mul...This study aims to develop a high-precision and cost-efficient method for the threedimensional reconstruction of large particles in natural gravel and blasted rock fragments,utilizing Structure from Motion(SfM)and Multi-View Stereo(MVS)techniques.The proposed approach was applied to characterize the three-dimensional morphology of rockfill dam materials at a real construction site.Particle shape was quantitatively analyzed using shape indices of sphericity,convexity,and angularity.The predominant morphology of natural gravel is characterized as slightly elongated and slightly flat,while rock fragments are slightly elongated and not flat.Probability density distributions of shape indices follow a skewed normal distribution:sphericity and convexity show leftward skewness,whereas angularity is right-skewed.Skewness parameters of sphericity and angularity are consistent between natural gravel and blasted rock fragments,indicating comparable shape asymmetry.Convexity skewness is significantly higher in natural gravel compared to rock fragments,by approximately an order of magnitude.The relationship between size and particle shape shows that form ratios and associated shape descriptors change linearly with the logarithm of size;larger particles approach spherical or cubic forms.The innovative measurements contribute to the particle shape data set of rockfill dam materials,providing valuable insights into the three-dimensional and statistical morphological characteristics of relatively large particles in natural gravel and blasted rock fragments.This approach enhances understanding of particle morphology's impact on the mechanical behavior of granular materials.展开更多
Accurately acquiring catalyst size and morphology is essential for supporting catalytic reaction process design and optimal control. We report an intelligent catalyst sizing and morphological classification method bas...Accurately acquiring catalyst size and morphology is essential for supporting catalytic reaction process design and optimal control. We report an intelligent catalyst sizing and morphological classification method based on the Mask-RCNN framework. A dataset of 9880 high-resolution images was captured by using a self-made fiber-optic endoscopic system for 13 kinds of silicoaluminophosphate-34 (SAPO-34) catalyst samples with different coke. Then there were approximately 877881 individual particles extracted from this dataset by our AI-based particle recognition algorithm. To clearly describe the morphology of irregular particles, we proposed a hybrid classification criterion that combines five different parameters, which are deformity, circularity, roundness, aspect ratio, and compactness. Therefore, catalyst morphology can be classified into two categories with four types. The first category includes regular types, such as the spherical, ellipsoidal, and rod-shaped types. And all the irregular types fall into the second category. The experimental results showed that a catalyst particle tends to be larger when its coke deposition increased. Whereas particle morphology remained primarily spherical and ellipsoidal, the ratio of each type varied slightly according to its coke. Our findings illustrate that this is a promising approach to be developing intelligent instruments for catalyst particle sizing and classification.展开更多
Multimaterial digital light processing(DLP)three-dimensional(3D)printing technology provides unique advantages in the field of multi material additive manufacturing(MM AM)with its high resolution and rapid shaping cap...Multimaterial digital light processing(DLP)three-dimensional(3D)printing technology provides unique advantages in the field of multi material additive manufacturing(MM AM)with its high resolution and rapid shaping capabilities based on photopolymerization.However,owing to differences in the curing behavior and physical properties of different materials,multimaterial DLP 3D printing faces challenges such as insufficient interfacial bonding strength and unstable mechanical properties.In this study,two resins were integrated by multimaterial DLP 3D printing technology,and the effects of different layer thicknesses and exposure times on the interfacial bonding strength and morphology of the multimaterials were systematically investigated.The interfacial bonding mechanisms of the two resins was analyzed.It was found that increasing the exposure time can improve the interfacial bonding strength between materials,but certain limitations exist.A mathematical model relating the interfacial bonding strength to the exposure time and layer thickness was developed,and optimal process parameters were determined using optimization algorithms.A variable-parameter printing strategy for the interface was proposed to further improve the performance of printed parts.The maximum tensile strength of the multimaterial samples(44.43 MPa)using this strategy reached that of single-material parts(45 MPa),validating the feasibility of this strategy.This provides guidance for multimaterial DLP 3D printing processes and offers valuable insights for the future additive manufacturing of high-performance multimaterial components.展开更多
The sedimentary bed morphology modulated by the wake flow of a wall-mounted flexible aquatic vegetation blade across various structural aspect ratios(A_(R)=l/b,where l and b are the length and width of the blade,respe...The sedimentary bed morphology modulated by the wake flow of a wall-mounted flexible aquatic vegetation blade across various structural aspect ratios(A_(R)=l/b,where l and b are the length and width of the blade,respectively)and incoming flow velocities was experimentally investigated in a water channel.A surface scanner was implemented to quantify bed topography,and a tomographic particle image velocimetry system was used to characterize the three-dimensional wake flows.The results showed that due to the deflection of incoming flow,the velocity magnitude increased at the lateral sides of the blade,thereby producing distinctive symmetric scour holes in these regions.The normalized morphology profiles of the sedimentary bed,which were extracted along the streamwise direction at the location of the maximum erosion depth,exhibited a self-similar pattern that closely followed a sinusoidal wave profile.The level of velocity magnitude enhancement was highly correlated to the postures of the flexible blade.At a given flow velocity,the blade with lower aspect ratios exhibited less significant deformation,causing more significant near-bed velocity enhancement in the wake deflection zone and therefore leading to higher erosion volumes.Further investigation indicated that when the blade underwent slight deformation,the larger velocity enhancement close to the bed can be attributed to more significant flow deflection effects at the lateral sides of the blade and stronger flow mixing with high momentum flows away from the bed.Supported with measurements,a basic formula was established to quantify the shear stress acting on the sedimentary bed as a function of incoming flow velocity and blade aspect ratio.展开更多
In order to enhance the wear resistance of 45 steel,a WC/Stellite 6 composite layer with 30%WC which with different morphologies(spherical and irregular)was prepared on the surface of 45 steel by laser cladding techno...In order to enhance the wear resistance of 45 steel,a WC/Stellite 6 composite layer with 30%WC which with different morphologies(spherical and irregular)was prepared on the surface of 45 steel by laser cladding technology.The effects of WC morphology on the phase composition,microstructure,microhardness,and wear resistance of the cladding layer were compared and analyzed.The res-ults show that the surface of the cladding layer was well formed.M_(23)C_(6),M_(7)C_(3),WC,and W_(2)C exist in both cladding layers.With the ad-dition of spherical WC,the diffraction peaks of γ-Co appear on the left side of the main peak of Co6W6C.The area of intergranular carbides accounts for a large proportion in the surface layer which with the fine grains.During the process of laser cladding the spherical WC particles with loose structure are prone to melting,including their interior.However,the melting amount of irregular WC particles is finite,which only occurs on the periphery of the particles,and the particle interior is relatively intact.The microhard-ness of two cladding layers gradient increases from the substrate to the surface layer.The surface layer added spherical WC has high-er microhardness,which reaches 790.6 HV1.Nevertheless,the wear resistance of the cladding layer added irregular WC is better than that of the cladding layer added spherical WC.The reason is because that the incompletely melted irregular WC particles are uni-formly distributed in the cladding layer which provided the support points for the cladding layer matrix during the wear process,the wear of the cladding layer by the grinding pair is reduced consequently.展开更多
Aerosol category and its physicochemical properties are key factors influencing its climate and environmental effects.To further enhance our understanding of aerosols in the Himalayas-Tibetan Plateau region,atmospheri...Aerosol category and its physicochemical properties are key factors influencing its climate and environmental effects.To further enhance our understanding of aerosols in the Himalayas-Tibetan Plateau region,atmospheric particulate matter samples were collected at three different altitudes on Mount Qomolangma(Everest).Using an automated scanning electron microscope system,the composition,size,and morphology of 52,349 particles were analyzed.The average mass concentrations of PM_(1),PM_(2.5),and PM_(10)were 0.678,5.054,and 16.698μg/m^(3),respectively.Aluminosilicate particles dominated the samples,accounting for 71.5%to 82.8%of PM_(10)mass and 34.7%to 62.4%of the particle number.Quartz particles,carbonate particles,metal oxides,and sulfates were also observed at different periods.Carbonaceous particles made up a significant portion of aerosols,comprising 2.1%to 9.7%of PM_(10)mass and 10.4%to 45.4%of particle number,with their concentration showing an upward trend with altitude.Small amounts of tar ball particles and fly ash particles were also observed,providing direct evidence of anthropogenic influences on high-altitude regions,even at altitudes exceeding 6000 m.The size distribution and abundance of different particle categories were closely related to the transport trajectories of air masses.The morphology of different particle categories varied,with fly ash particles mainly spherical and carbonaceous particles exhibiting higher irregularity.展开更多
Background:The endoscopic appearance of the major duodenal papilla influences biliary cannulation and complications.This study aimed to investigate the role of major duodenal papillae in the endoscopic treatment of co...Background:The endoscopic appearance of the major duodenal papilla influences biliary cannulation and complications.This study aimed to investigate the role of major duodenal papillae in the endoscopic treatment of common bile duct(CBD)stones.Methods:This retrospective study was conducted at Bishan Hospital of Chongqing Medical University between January 2018 and August 2022.Patients with native papillae who underwent endoscopic treatment for CBD stones were recruited and divided into four groups according to Haraldsson's classification of papillae(typesⅠ-Ⅳ).Univariate and multivariate logistic regression analyses were used to identify risk factors for difficult cannulation and post-endoscopic retrograde cholangiopancreatography(ERCP)pancreatitis(PEP).Results:A total of 596 patients with CBD stones were enrolled.The proportion of patients with typeⅠpapilla was the highest(n=231,38.8%),followed by typeⅢpapilla(n=175,29.4%),typeⅣpapilla(n=101,16.9%)and typeⅡpapilla(n=89,14.9%).Difficult cannulation occurred in 188 of 596 patients(31.5%),with most cases occurring in those with typeⅢpapilla(71/175,40.6%,P=0.020).Multivariate logistic analysis revealed that age[odds ratio(OR)=1.034,95%confidence interval(CI):1.021–1.047,P<0.001],typeⅢpapilla(OR=2.255,95%CI:1.439–3.535,P<0.001),gallbladder in situ(OR=2.486,95%CI:1.346–4.590,P=0.004),and CBD diameter<10 mm(OR=1.600,95%CI:1.049–2.441,P=0.029)were risk factors for difficult cannulation.The total incidence of PEP was 10.9%.Compared with the other types of papillae,the rate of PEP was the highest in those with typeⅠpapilla(15.2%,P=0.030).Multivariate analysis demonstrated that PEP was associated with difficult cannulation(OR=1.811,95%CI:1.044–3.143,P=0.035)and white blood cells(WBCs)<10×10~9/L(OR=2.199,95%CI:1.051–4.600,P=0.036).Conclusions:The endoscopic appearance of the major papilla is an important factor that influences both biliary cannulation and outcomes.TypeⅢpapilla is more frequently difficult to cannulate in the endoscopic treatment of CBD stones.展开更多
A macro-tidal tropical estuary with high fluvial discharge is characterized by both fragility and remarkable dynamism.This study utilizes the Salween River Delta(SRD)as a case example to examine the interplay between ...A macro-tidal tropical estuary with high fluvial discharge is characterized by both fragility and remarkable dynamism.This study utilizes the Salween River Delta(SRD)as a case example to examine the interplay between morphology and vegetation under similar tidal conditions.Our analysis of correlations and inferences revealed several significant trends in the SRD:(1)an overall expansion of land area and intertidal vegetation,with the most pronounced changes occurring in the eastern sector;(2)the predominance of river discharge influencing the southwestern and northern sectors,contrasted with the primary impact of storm surges in the eastern sector;and(3)three distinct causal relationships among estuarine morphology,vegetation,storm surges,and river discharge:a direct model where river discharge shapes estuarine morphology,a progressive model in which river discharge affects vegetation distribution,subsequently influencing estuarine morphology,and a hybrid model where storm surges directly impact vegetation and indirectly modify its distribution through changes in estuarine morphology.The stability of sediment supply and the role of intertidal vegetation are crucial for the continuous seaward advance,providing a vital foundation for the protection and development of estuarine deltas.展开更多
基金funded by the National Science Centre,Poland,on the basis of the decision number UMO-2020/37/B/ST8/02097supported by the program“Excellence Initiative-Research University”for the AGH University of Krakow(IDUB AGH,No.501.696.7996,Action 4,ID 9880).
文摘Multicomponent Gd_(1−x)Sm_(x)Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)double perovskites are optimized for application in terms of chemical composi-tion and morphology for the use as oxygen electrodes in solid oxide cells.Structural studies of other physicochemical properties are con-ducted on a series of materials obtained by the sol-gel method with different ratios of Gd and Sm cations.It is documented that changing the x value,and the resulting adjustment of the average ionic radius,have a significant impact on the crystal structure,stability,as well as on the total conductivity and thermomechanical properties of the materials,with the best results obtained for the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)composition.Oxygen electrodes are prepared using the selected compound,allowing to obtain low polarization resistance values,such as 0.086Ω·cm^(2)at 800℃.Systematic studies of electrocatalytic activity are conducted using La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(_(0.2))O_(3−δ)as the electrolyte for all electrodes,and Ce_(0.8)Gd_(0.2)O_(2−δ)electrolyte for the best performing Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes.The electrochemical data are analyzed using the distribution of relaxation times method.Also,the influence of the preparation method of the electrode material is in-ve`stigated using the electrospinning technique.Finally,the performance of the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes is tested in a Ni-YSZ(yttria-stabilized zirconia)anode-supported cell with a Ce_(0.8)Gd_(0.2)O_(2−δ)buffer layer,in the fuel cell and electrolyzer operating modes.With the electrospun electrode,a power density of 462 mW·cm^(−2)is obtained at 700℃,with a current density of ca.0.2 A·cm^(−2)at 1.3 V for the electrolysis at the same temperature,indicating better performance compared to the sol-gel-based electrode.
基金supported by National Natural Science Foundation of China(Grant Nos.52305440,52204263)Natural Science Foundation of Changsha City(Grant Nos.kq2208272,kq2208274)+1 种基金Tribology Science Fund of the State Key Laboratory of Tribology in Advanced Equipment(Grant SKLTKF22B09)National Key Research and Development Program of China(2022YFB3706902).
文摘Laser-directed energy deposition(L-DED)is an advanced additive manufacturing technology primarily adopted in metal three-dimensional printing systems.The L-DED process is characterized by various defects,thus necessitating the extensive use of in-situ monitoring to enable real-time adjustments of process parameters by detecting molten-pool features.To address the challenge of accurately extracting the molten-pool morphology from an undetached spatter,an innovative monitoring method based on the U-Net(U-shaped network)is proposed herein.A lightweight architecture accelerates the processing speed,whereas an enhanced loss function incorporating weight maps augments the segmentation precision.The model performance is evaluated by comparing its segmentation accuracy and processing speed with those of the conventional U-Net,using the mean intersection over union(MIoU)as the segmentation metric.The improved model demonstrates superior segmentation accuracy at the interface between the molten pool and spatter,with a peak MIoU of 0.9798 achieved on the test set.Furthermore,this model processes each image in an extremely short time of 17.9 ms.Using this segmentation algorithm,the error in extracting the molten-pool width from single-track experiments is within 0.1 mm.The proposed method for monitoring the molten-pool morphology is suitable for deployment in online monitoring systems,thus providing a foundation for subsequent process-parameter regulation.
基金supported by the National Key Research and Development Program of China,No.2021ZD0202503(to AHT)the National Natural Science Foundation of China,Nos.31872759(to AHT)and 32070707(to CF)+1 种基金Shenzhen Science and Technology Program,No.RCJC20210609104333007(to ZW)Shenzhen-Hong Kong Institute of Brain Science,Shenzhen Fundamental Research Institutions,No.2021SHIBS0002(to ZW).
文摘Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and memory.Kinesin-4 KIF21A helps organize the microtubule-actin network at the cell cortex by interacting with KANK1;however,whether KIF21A modulates dendritic structure and function in neurons remains unknown.In this study,we found that KIF21A was distributed in a subset of dendritic spines,and that these KIF21A-positive spines were larger and more structurally plastic than KIF21A-negative spines.Furthermore,the interaction between KIF21A and KANK1 was found to be critical for dendritic spine morphogenesis and synaptic plasticity.Knockdown of either KIF21A or KANK1 inhibited dendritic spine morphogenesis and dendritic branching,and these deficits were fully rescued by coexpressing full-length KIF21A or KANK1,but not by proteins with mutations disrupting direct binding between KIF21A and KANK1 or binding between KANK1 and talin1.Knocking down KIF21A in the hippocampus of rats inhibited the amplitudes of long-term potentiation induced by high-frequency stimulation and negatively impacted the animals’cognitive abilities.Taken together,our findings demonstrate the function of KIF21A in modulating spine morphology and provide insight into its role in synaptic function.
基金funded by the National Natural Science F oundation of China(No.52172205)。
文摘Zinc oxide(ZnO)serves as a crucial functional semiconductor with a wide direct bandgap of approximately 3.37 eV.Solvothermal reaction is commonly used in the synthesis of ZnO micro/nanostructures,given its low cost,simplicity,and easy implementation.Moreover,ZnO morphology engineering has become desirable through the alteration of minor conditions in the reaction process,particularly at room temperature.In this work,ZnO micro/nanostructures were synthesized in a solution by varying the amounts of the ammonia added at low temperatures(including room temperature).The formation of Zn^(2+)complexes by ammonia in the precursor regulated the reaction rate of the morphology engineering of ZnO,which resulted in various structures,such as nanoparticles,nanosheets,microflowers,and single crystals.Finally,the obtained ZnO was used in the optoelectronic application of ultraviolet detectors.
基金supported by the National Natural Science Foundation of China(22376063,21976057)the Fund of the National Engineering Laboratory for Mobile Source Emission Control Technology(NELMS2020A05)Fundamental Research Funds for the Central Universities.
文摘The preferential oxidation of CO(CO-PROX)reaction is a cost-effective method for eliminating trace amounts of CO from the fuel H2.Pt-based catalysts have been extensively studied for COPROX,with their activity influenced by the morphology of the support.Hydrothermal synthesis was employed to produce different morphologies ofγ-Al_(2)O_(3):flower-likeγ-Al_(2)O_(3)(f)exposing(110)crystal faces,sheet-likeγ-Al_(2)O_(3)(s)revealing(100)crystal faces,and rod-likeγ-Al_(2)O_(3)(r)displaying(111)crystal faces,followed by loading PtCo nanoparticles.The exposed crystal faces of the support impact the alloying degree of the PtCo nanoparticles,and an increase in the alloying degree correlates with enhanced catalyst reactivity.Pt_(3)Co intermetallic compounds were identified onγ-Al_(2)O_(3)(f)exposing(110)crystal faces,and PtCo/γ-Al_(2)O_(3)(f)showed high catalytic activity in the CO-PROX reaction,achieving 100%CO conversion across a broad temperature range of 50−225°C.In contrast,only partial alloying of PtCo was observed onγ-Al_(2)O_(3)(s).Furthermore,no alloying between Pt and Co occurred in PtCo/γ-Al_(2)O_(3)(r),resulting in a reaction rate at 50°C that was merely 11%of that of PtCo/γ-Al_(2)O_(3)(f).The formation of Pt3Co intermetallic compounds led to a more oxidized state of Pt,which significantly diminished the adsorption of CO on Pt and augmented the active oxygen species,thereby facilitating the selective oxidation of CO.
文摘Harrat Lunayyir,a volcanic field in western Saudi Arabia,exhibits diverse geomorphological and topographical features shaped by volcanic,tectonic,and climatic processes.This study integrates field observations,remote sensing,and GIS analysis to investigate the spatial distribution and relationships between volcanic landforms,lava flows,and topographical variation result obtained is a morphological classification of the cinder cones of Harrat Lunayyir,which can be sub-divided into four types:tephra rings,horseshoe-shaped volcanoes,multiple volcanoes and volcanoes without craters.All of these are monogenetic volcanoes,unlike central volcanoes(stratovolcanoes)which live for tens or hundreds of thousands of years and erupt numerous times.In Harrat Lunayyir,there is a clear dominance of arched horseshoe-shaped volcanoes(58)over ring-shaped cinder cones(10),A1_symmetric cones(circular,uniform cinder cones with a single crater)(32),A2_asymmetric cones(elongated,irregular cones and may feature one or more craters)(8),volcanoes without craters(55)and multiple volcanoes(20).The classification presented in this paper makes it possible to include all morphological types of volcanoes found in the region.This fact also renders the present classification a useful tool to apply in other,both insular and continental volcanic areas to eventually analyze and systematize the study of eruptive edifices with similar traits.Hence,this research will explore the standard physical volcanology literature so as to follow accepted definitions.
基金Fujian Province Science and Technology Plan Project under contract No.2023N0011Xiamen Municipal Bureau of Marine Development Project under contract No.S24258。
文摘Cryptocaryon irritans is the parasite responsible for“white spot disease”in the yellowfin seabream Acanthopagrus latus,which has caused significant losses to the aquaculture industry.This experiment investigated the changes in the morphology,transcriptome,and proteome of gill tissue in yellowfin seabream infected with C.irritans,aiming to provide foundational data for further understanding the pathogenic mechanisms and control measures against this parasite.The main findings were as follows,after C.irritans infection,the structure of gill tissue in yellowfin seabream was damaged,with microvessels ruptured,some cells proliferating,and large amounts of mucus infiltrating.Transcriptome analysis revealed a total of 4299 differentially expressed genes,with 2367 up-regulated and 1932down-regulated.Further bioinformatics analysis of all differentially expressed genes identified nine immune-related genes,cox-2,mcama,tbx21,dcn,tnfb,cd74a,illb,ppib,and cd4-1 in A.latus.The reliability of the transcriptome data was validated by real time q PCR,which showed the same trend as the RNA-seq results.Proteome analysis found365 differential proteins,with 180 proteins up-regulated and 185 proteins down-regulated.Bioinformatics analysis identified three immune-related proteins,Myll,Gapdh,and Actn3b.These findings indicated that C.irritans disrupted the structure of gill tissue,impeded gas exchange and led to asphyxiation and death in affected fish.Transcriptome and proteome analyses showed that the expression of immune-related genes and proteins in yellowfin seabream,involved not only inflammatory responses and the activation and migration of immune cells but also potentially participated in tissue repair and defense regulation.These findings highlighted the complex immune regulatory network in response to C.irritans infection,offering references for prevention and control of white spot disease in yellowfin seabream.
文摘The East China Sea(ECS)off the Coast of Zhoushan Archipelago,Zhejiang(ECS-CZA)is home to abundant fishery resources and an important spawning,feeding,and nursing ground for a variety of fish species.Due to long-term overfishing,the ichthyoplankton structure has been dramatically altered.Understanding the species composition and distribution of fish eggs and larvae is one of the most essential tasks to accurately regulate fishery resources and formulate effective management policies;however,little is known about the ichthyoplankton in this region.In this study,an integrated strategy of morphology identification(MI)and mitochondrial COI DNA barcoding was used to identify species of fish eggs and larvae collected from the ECSCZA.MI revealed 15 fish egg species belonging to 12 families and 12 fish larva species belonging to 12 families;in contrast,DNA barcoding altogether identified 30 species,including 18 fish egg species and 13 fish larva species.One species was shared between the egg and larva samples.Our study offers useful tools and critical scientific information for further understanding the diversity,distribution,and conservation management of various ichthyoplankton species in the marine environment.
文摘This is a correction to:Isabela R R Moraes,Mariana Antunes,Laura S Lopez-Greco,Fernando Jose Zara,Antonio Leao Castilho,Functional reproductive morphology of the snapping shrimp genus Synalpheus Spence Bate,1888(Decapoda,Alpheidae),Current Zoology,2024,71,338-352;https:/doi.org/10.1093/cz/zoae053.
基金supported by the National Key R&D Program of China(2020YFE0205900 and 2022YEF0203200)the STI 2030-Major Project(2021ZD0200104 and 2022ZD0205203)+2 种基金the Shenzhen Science and Technology Program(RCYX20210706092100003,RCBS20221008093311027,and JCYJ20210324102006018)the Youth Innovation Promotion Association CAS(2022367)the Shenzhen Technological Research Center for Primate Translational Medicine grant(XMHT20220104005).
文摘Dear Editor,The primary motor cortex,also known as MOp in rodents,F1,or M1 in primates[1],plays a crucial role in autonomous motor control.It is interconnected with other motor control structures such as the basal ganglia,thalamus,and brainstem.Among these connections,the corticostriatal system plays a significant role in functions including action selection,motor control,sequence learning,and habit formation[2].
基金Yunnan Provincial Science and Technology Project at Southwest United Graduate School,No.202302AO370012National Natural Science Foundation of China,No.42401510Postdoctoral Fellowship Program of CPSF,No.GZC20240017。
文摘Morphology,the study of shapes or forms,when applied to tourism,emphasizes the multifarious spatial practices between morphological elements and tourism activities.However,existing literature on morphology in the context of tourism usually only focuses on a single or a limited number of study areas,overlooking common or even universal patterns across various tourism destinations.To address this gap,we utilize geospatial big data and present a case study on the morphology of 406“AAAAA”-rated scenic areas in China.A framework based on“points”,“lines”,“planes”,and“solids”was designed to systematically organize and analyze morphological elements across scenic areas.The findings provide valuable insights for tourism planning and development,such as the co-occurrence of dense road networks and fragmented landscapes within scenic areas,as well as the resourcecontext-influenced(cultural or natural)associations between morphological features and tourism indicators.This research provides valuable strategic guidance for more effective and informed tourism development while acknowledging the trade-offs between generalizability and local specificity.
基金National Natural Science Foundation of China,Grant/Award Numbers:52279066,U2340217Fundamental Research Funds for Central Welfare Research Institutes,Grant/Award Number:TKS20240402National Key Research and Development Program of China,Grant/Award Number:2023YFC3209500。
文摘The operation of cascade reservoirs in a watershed profoundly exerts river watersediment dynamics and topography evolution,and the terminal reservoir is the focus area for river and waterway management.This paper reveals the process and underlying factors of topography evolution and water level adjustment in the lower Hanjiang River under the action of cascade reservoirs.This study focused on the 263 km river channel downstream of the Xinglong Hydropower Conservancy Project on the Hanjiang River.Using measured flow,sediment,and topography data from 1977 to 2023,we analyzed the changing characteristics of riverbed scouring and deposition intensity,thalweg,and cross-sections.Additionally,we evaluated the response relationship between riverbed scouring and deposition intensity and factors such as sediment transport,runoff,and human activities.From 1977 to 2023,the low-water channel in the Xinglong-Estuary reaches showed a scouring and cutting tendency,and the riverbed slop initially decreased and then increased.The main cause of the riverbed scouring along the Xinglong-Estuary reaches was the reduced sediment load in the watershed,with waterway engineering having a slightly larger influence than runoff in the Xinglong-Xiantao reaches;by contrast,runoff exerted a more significant effect than both waterway engineering and the Yangtze River water level decline in the Xiantao-Estuary reaches.During the autumn flood season from 1983 to 2023,the water level differences between the Hanjiang and Yangtze Rivers at the same flow rate showed an increasing trend,leading to an increase in water surface slope,which intensified scouring forces and riverbed scouring.This study improves our understanding of the impacts of dam construction on river topographical evolution,water level changes,and deep‐water waterway resources.
基金National Natural Science Foundation of China,Grant/Award Numbers:51809290,51979093,52239009Project funded by Tibet Autonomous Region Key R&D Plan,Grant/Award Number:XZ202101ZY0002GPostgraduate Research&Practice Innovation Program of Jiangsu Province,Grant/Award Number:No.KYCX22_0656。
文摘This study aims to develop a high-precision and cost-efficient method for the threedimensional reconstruction of large particles in natural gravel and blasted rock fragments,utilizing Structure from Motion(SfM)and Multi-View Stereo(MVS)techniques.The proposed approach was applied to characterize the three-dimensional morphology of rockfill dam materials at a real construction site.Particle shape was quantitatively analyzed using shape indices of sphericity,convexity,and angularity.The predominant morphology of natural gravel is characterized as slightly elongated and slightly flat,while rock fragments are slightly elongated and not flat.Probability density distributions of shape indices follow a skewed normal distribution:sphericity and convexity show leftward skewness,whereas angularity is right-skewed.Skewness parameters of sphericity and angularity are consistent between natural gravel and blasted rock fragments,indicating comparable shape asymmetry.Convexity skewness is significantly higher in natural gravel compared to rock fragments,by approximately an order of magnitude.The relationship between size and particle shape shows that form ratios and associated shape descriptors change linearly with the logarithm of size;larger particles approach spherical or cubic forms.The innovative measurements contribute to the particle shape data set of rockfill dam materials,providing valuable insights into the three-dimensional and statistical morphological characteristics of relatively large particles in natural gravel and blasted rock fragments.This approach enhances understanding of particle morphology's impact on the mechanical behavior of granular materials.
基金supported by the National Natural Science Foundation of China(22308348)the Natural Science Foundation of Liaoning Province of China(2024-MSBA-65)+1 种基金the Qin Chuangyuan Project for Introducing High-Level Innovative and Entrepreneurial Talents(QCYRCXM-2023-024)the Energy Revolution S&T Program of Yulin Innovation Institute of Clean Energy(E201041206).
文摘Accurately acquiring catalyst size and morphology is essential for supporting catalytic reaction process design and optimal control. We report an intelligent catalyst sizing and morphological classification method based on the Mask-RCNN framework. A dataset of 9880 high-resolution images was captured by using a self-made fiber-optic endoscopic system for 13 kinds of silicoaluminophosphate-34 (SAPO-34) catalyst samples with different coke. Then there were approximately 877881 individual particles extracted from this dataset by our AI-based particle recognition algorithm. To clearly describe the morphology of irregular particles, we proposed a hybrid classification criterion that combines five different parameters, which are deformity, circularity, roundness, aspect ratio, and compactness. Therefore, catalyst morphology can be classified into two categories with four types. The first category includes regular types, such as the spherical, ellipsoidal, and rod-shaped types. And all the irregular types fall into the second category. The experimental results showed that a catalyst particle tends to be larger when its coke deposition increased. Whereas particle morphology remained primarily spherical and ellipsoidal, the ratio of each type varied slightly according to its coke. Our findings illustrate that this is a promising approach to be developing intelligent instruments for catalyst particle sizing and classification.
基金supported by National Key R&D Program of China(Grant No.2022YFB4600103)National Youth Talent Support Program,China Postdoctoral Science Foundation(Grant No.2021M692555)+1 种基金Shaanxi Province Qinchuangyuan'Scientists+Engineers'Team Building Project(Grant No.2023KXJ-266)Fundamental Research Funds for the Central Universities(Grant No.xzy012023145)。
文摘Multimaterial digital light processing(DLP)three-dimensional(3D)printing technology provides unique advantages in the field of multi material additive manufacturing(MM AM)with its high resolution and rapid shaping capabilities based on photopolymerization.However,owing to differences in the curing behavior and physical properties of different materials,multimaterial DLP 3D printing faces challenges such as insufficient interfacial bonding strength and unstable mechanical properties.In this study,two resins were integrated by multimaterial DLP 3D printing technology,and the effects of different layer thicknesses and exposure times on the interfacial bonding strength and morphology of the multimaterials were systematically investigated.The interfacial bonding mechanisms of the two resins was analyzed.It was found that increasing the exposure time can improve the interfacial bonding strength between materials,but certain limitations exist.A mathematical model relating the interfacial bonding strength to the exposure time and layer thickness was developed,and optimal process parameters were determined using optimization algorithms.A variable-parameter printing strategy for the interface was proposed to further improve the performance of printed parts.The maximum tensile strength of the multimaterial samples(44.43 MPa)using this strategy reached that of single-material parts(45 MPa),validating the feasibility of this strategy.This provides guidance for multimaterial DLP 3D printing processes and offers valuable insights for the future additive manufacturing of high-performance multimaterial components.
基金supported by the National Science Foundation under Grant No.2327916.
文摘The sedimentary bed morphology modulated by the wake flow of a wall-mounted flexible aquatic vegetation blade across various structural aspect ratios(A_(R)=l/b,where l and b are the length and width of the blade,respectively)and incoming flow velocities was experimentally investigated in a water channel.A surface scanner was implemented to quantify bed topography,and a tomographic particle image velocimetry system was used to characterize the three-dimensional wake flows.The results showed that due to the deflection of incoming flow,the velocity magnitude increased at the lateral sides of the blade,thereby producing distinctive symmetric scour holes in these regions.The normalized morphology profiles of the sedimentary bed,which were extracted along the streamwise direction at the location of the maximum erosion depth,exhibited a self-similar pattern that closely followed a sinusoidal wave profile.The level of velocity magnitude enhancement was highly correlated to the postures of the flexible blade.At a given flow velocity,the blade with lower aspect ratios exhibited less significant deformation,causing more significant near-bed velocity enhancement in the wake deflection zone and therefore leading to higher erosion volumes.Further investigation indicated that when the blade underwent slight deformation,the larger velocity enhancement close to the bed can be attributed to more significant flow deflection effects at the lateral sides of the blade and stronger flow mixing with high momentum flows away from the bed.Supported with measurements,a basic formula was established to quantify the shear stress acting on the sedimentary bed as a function of incoming flow velocity and blade aspect ratio.
基金supported by the National Natural Science Foundation of China(52161007)Science and Technology Planning Project of Guangdong Province of China(20170902,20180902)+1 种基金Science and Technology Planning Project of Yangjiang City of Guangdong Province(SDZX2020009)Research project of Shenzhen city(JSGG20210420091802007).
文摘In order to enhance the wear resistance of 45 steel,a WC/Stellite 6 composite layer with 30%WC which with different morphologies(spherical and irregular)was prepared on the surface of 45 steel by laser cladding technology.The effects of WC morphology on the phase composition,microstructure,microhardness,and wear resistance of the cladding layer were compared and analyzed.The res-ults show that the surface of the cladding layer was well formed.M_(23)C_(6),M_(7)C_(3),WC,and W_(2)C exist in both cladding layers.With the ad-dition of spherical WC,the diffraction peaks of γ-Co appear on the left side of the main peak of Co6W6C.The area of intergranular carbides accounts for a large proportion in the surface layer which with the fine grains.During the process of laser cladding the spherical WC particles with loose structure are prone to melting,including their interior.However,the melting amount of irregular WC particles is finite,which only occurs on the periphery of the particles,and the particle interior is relatively intact.The microhard-ness of two cladding layers gradient increases from the substrate to the surface layer.The surface layer added spherical WC has high-er microhardness,which reaches 790.6 HV1.Nevertheless,the wear resistance of the cladding layer added irregular WC is better than that of the cladding layer added spherical WC.The reason is because that the incompletely melted irregular WC particles are uni-formly distributed in the cladding layer which provided the support points for the cladding layer matrix during the wear process,the wear of the cladding layer by the grinding pair is reduced consequently.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(No.2019QZKK0106)the Basic Research Fund of CAMS(Nos.2023Z004 and 2023Z015).
文摘Aerosol category and its physicochemical properties are key factors influencing its climate and environmental effects.To further enhance our understanding of aerosols in the Himalayas-Tibetan Plateau region,atmospheric particulate matter samples were collected at three different altitudes on Mount Qomolangma(Everest).Using an automated scanning electron microscope system,the composition,size,and morphology of 52,349 particles were analyzed.The average mass concentrations of PM_(1),PM_(2.5),and PM_(10)were 0.678,5.054,and 16.698μg/m^(3),respectively.Aluminosilicate particles dominated the samples,accounting for 71.5%to 82.8%of PM_(10)mass and 34.7%to 62.4%of the particle number.Quartz particles,carbonate particles,metal oxides,and sulfates were also observed at different periods.Carbonaceous particles made up a significant portion of aerosols,comprising 2.1%to 9.7%of PM_(10)mass and 10.4%to 45.4%of particle number,with their concentration showing an upward trend with altitude.Small amounts of tar ball particles and fly ash particles were also observed,providing direct evidence of anthropogenic influences on high-altitude regions,even at altitudes exceeding 6000 m.The size distribution and abundance of different particle categories were closely related to the transport trajectories of air masses.The morphology of different particle categories varied,with fly ash particles mainly spherical and carbonaceous particles exhibiting higher irregularity.
文摘Background:The endoscopic appearance of the major duodenal papilla influences biliary cannulation and complications.This study aimed to investigate the role of major duodenal papillae in the endoscopic treatment of common bile duct(CBD)stones.Methods:This retrospective study was conducted at Bishan Hospital of Chongqing Medical University between January 2018 and August 2022.Patients with native papillae who underwent endoscopic treatment for CBD stones were recruited and divided into four groups according to Haraldsson's classification of papillae(typesⅠ-Ⅳ).Univariate and multivariate logistic regression analyses were used to identify risk factors for difficult cannulation and post-endoscopic retrograde cholangiopancreatography(ERCP)pancreatitis(PEP).Results:A total of 596 patients with CBD stones were enrolled.The proportion of patients with typeⅠpapilla was the highest(n=231,38.8%),followed by typeⅢpapilla(n=175,29.4%),typeⅣpapilla(n=101,16.9%)and typeⅡpapilla(n=89,14.9%).Difficult cannulation occurred in 188 of 596 patients(31.5%),with most cases occurring in those with typeⅢpapilla(71/175,40.6%,P=0.020).Multivariate logistic analysis revealed that age[odds ratio(OR)=1.034,95%confidence interval(CI):1.021–1.047,P<0.001],typeⅢpapilla(OR=2.255,95%CI:1.439–3.535,P<0.001),gallbladder in situ(OR=2.486,95%CI:1.346–4.590,P=0.004),and CBD diameter<10 mm(OR=1.600,95%CI:1.049–2.441,P=0.029)were risk factors for difficult cannulation.The total incidence of PEP was 10.9%.Compared with the other types of papillae,the rate of PEP was the highest in those with typeⅠpapilla(15.2%,P=0.030).Multivariate analysis demonstrated that PEP was associated with difficult cannulation(OR=1.811,95%CI:1.044–3.143,P=0.035)and white blood cells(WBCs)<10×10~9/L(OR=2.199,95%CI:1.051–4.600,P=0.036).Conclusions:The endoscopic appearance of the major papilla is an important factor that influences both biliary cannulation and outcomes.TypeⅢpapilla is more frequently difficult to cannulate in the endoscopic treatment of CBD stones.
基金National Natural Science Foundation of China,No.41906148,No.42271086Rejuvenating Yunnan Talents Support Plan Young Talent Program,No.XDYC-QNRC-2023-0322。
文摘A macro-tidal tropical estuary with high fluvial discharge is characterized by both fragility and remarkable dynamism.This study utilizes the Salween River Delta(SRD)as a case example to examine the interplay between morphology and vegetation under similar tidal conditions.Our analysis of correlations and inferences revealed several significant trends in the SRD:(1)an overall expansion of land area and intertidal vegetation,with the most pronounced changes occurring in the eastern sector;(2)the predominance of river discharge influencing the southwestern and northern sectors,contrasted with the primary impact of storm surges in the eastern sector;and(3)three distinct causal relationships among estuarine morphology,vegetation,storm surges,and river discharge:a direct model where river discharge shapes estuarine morphology,a progressive model in which river discharge affects vegetation distribution,subsequently influencing estuarine morphology,and a hybrid model where storm surges directly impact vegetation and indirectly modify its distribution through changes in estuarine morphology.The stability of sediment supply and the role of intertidal vegetation are crucial for the continuous seaward advance,providing a vital foundation for the protection and development of estuarine deltas.
