Standardization is necessary for the early industrialization of the new materials and technology.It is achieved by having agreed practices for the measurement of properties and other characteristics.The promising use ...Standardization is necessary for the early industrialization of the new materials and technology.It is achieved by having agreed practices for the measurement of properties and other characteristics.The promising use of graphene-based materials in fields like electronics,energy,and composites has resulted in standards for their nomenclature,the measurement of key characteristics,and their specification,etc.Among these,standards for measuring the key characteristics are crucial.The critical parameters are the number of layers,the type and concentration of defects and functional groups,elemental composition,sheet resistance,and carrier mobility.Standards for characterizing these have been analyzed by the International Organization for Standardization Technical Committee in ISO/TC229 and the International Electrotechnical Commission Technical Committee in IEC/TC113.These give details of applicable or preferred samples,the fundamental principles of the techniques,specific precautions,and points for attention in the relevant standards.The pivotal role of the ISO/TC229 and IEC/TC113 standards is considered and challenges and future trends are outlined.展开更多
39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.Ar...39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.ArcGIS inverse distance weight difference method was used to analyze the characteristics of pollution distribution,and single-factor pollution index,Nemerow comprehensive pollution index,ground accumulation index,and potential ecological risk index were selected to evaluate the characteristics of heavy metal pollution.Based on correlation analysis,the absolute principal component-multiple linear regression(APCS-MLR)and positive definite matrix factorization(PMF)models were used to analyze the sources of soil heavy metals.The results showed that the average concentrations of all eight heavy metals exceeded both national and Guangxi soil background values.Hg,Cd,and Zn exhibited high variation(greater than 0.5),indicating significant external disturbances,and their spatial distribution was closely related to mining activity locations.The single-factor pollution index evaluation indicated varying degrees of pollution risk for Cd,Zn,and As,with Cd and Zn being the most severe pollutants,as 69.23%and 30.77%of the samples fell into the moderate pollution or higher category.The geoaccumulation index analysis ranked the mean pollution levels of the eight elements as follows:Zn>Cd>Ni>Pb>Cu>Cr>Hg>As,with Cd and Zn showing the most severe contamination,and 51.28%of the samples exhibiting moderate or higher pollution levels.The Nemerow comprehensive pollution index evaluation showed that 74.35%of soil samples were classified as moderate to heavy pollution.The potential ecological risk index assessment indicated significant ecological risks posed by Cd and Zn,with 82.05%and 5.12%of the samples classified as causing strong to extreme ecological risks,respectively.The source apportionment analysis revealed minor differences between the two models.The APCS-MLR model identified three pollution sources and their contribution rates:anthropogenic mining sources(31.13%),parent material sources(40.38%),and unidentified sources(28.49%).The PMF model identified three pollution sources with contribution rates of anthropogenic mining sources(26.10%),parent material sources(46.96%),and a combined traffic and agricultural source(26.61%).Pb,Hg,Cd,and Zn mainly originated from mining activities;Cr,As,and Ni were primarily derived from the parent material,while Cu was predominantly attributed to traffic and agricultural sources.These findings provide a scientific basis for the prevention and control of heavy metal pollution in mining areas.展开更多
Extensive engineering experience and research findings suggest that rock mass instability is typically attributed to human engineering activities and natural disturbances,resulting in general dynamic mechanical proper...Extensive engineering experience and research findings suggest that rock mass instability is typically attributed to human engineering activities and natural disturbances,resulting in general dynamic mechanical properties.This is attributed to external interference resulting from the extensive use of the mechanical and blasting techniques necessary for mineral extraction.Quantifying the impact of dynamic disturbances on rock deformation behavior is essential for comprehending the long-term response of surrounding rock during excavation.This study placed the rock to sustained pressure and investigated the impact of varying hammer heights and dry and wet(W-D)damage on its shear failure behavior.This study investigated the fatigue disturbance studies on W-D damaged sandstone samples via W-D equipment,a disturbance creep device,digital image correlation(DIC),and acoustic emission(AE)technology.The experimental findings suggest that acoustic emission sensors can be utilized to quantify the internal damage of rock samples during cyclic impact,whereas DIC technology(optical measurement)is capable of capturing the surface crack propagation of samples.Under repeated impact and the combined action of W-D conditions,the bearing capacity of sandstone decreases,whereas the deformation capacity increases.Furthermore,the W-D cycles and impact strength are inversely related to the fatigue life.The intensity of W-D damage and disturbances further accelerates the development and propagation of cracks under cyclic disturbances.The research results are of preventive significance to ensure the safety and sustainable development of engineering construction.展开更多
Accurate and early evaluation of dental physiological characteristics is essential for effective disease detection and management.Polarization-sensitive optical coherence tomography(PS-OCT)is a noninvasive high-resolu...Accurate and early evaluation of dental physiological characteristics is essential for effective disease detection and management.Polarization-sensitive optical coherence tomography(PS-OCT)is a noninvasive high-resolution imaging technique that can obtain tooth structure and physiological features through intensity,retardation and degree of polarization uniformity(DOPU)images.In this study,we use the information provided by the PS-OCT system,especially the retardation information,to assess the physiological characteristics of teeth.In addition,we introduce a novel parameter—the rate of change of the retardation value(R)—to evaluate the magnitude of birefringence of enamel,which serves as an indicator of enamel health and mineralization.The results demonstrate that PS-OCT not only provides structural detail comparable to microcomputed tomography(microCT),but also yields additional physiological characteristics insights through polarization-based contrast.These findings highlight the strong potential of PS-OCT for early diagnosis,functional evaluation and personalized monitoring in dental care.展开更多
Clarifying the photosynthetic and population characteristics of conventional japonica rice at different yield levels is crucial for boosting yield and ensuring food security.Therefore,a two-year field trial with two c...Clarifying the photosynthetic and population characteristics of conventional japonica rice at different yield levels is crucial for boosting yield and ensuring food security.Therefore,a two-year field trial with two conventional japonica varieties was conducted at four planting densities:16 cm×30 cm(D1),14 cm×30 cm(D2),12 cm×30 cm(D3),and 10 cm×30 cm(D4).This study aimed to investigate how photosynthetic and population characteristics influence grain yield under varying planting densities.The results indicated that higher yields were primarily driven by increased grain weight and seed-setting rate(with a 9.68%‒11.40%higher single panicle weight),supported by optimized dry matter translocation and source-sink relationships.Elevated planting density(D2‒D4)enhanced panicle number and total spikelet number(by 3.91%‒15.00%)but reduced the number of spikelets per panicle,1000-grain weight,and photosynthetic efficiency due to mutual shading.Despite these trade-offs,yield increased by 4.10%‒12.42%under higher densities.The use of planting density D4 in japonica rice cultivation contributed to maximize yield.These findings provide important theoretical insights and practical significance for increasing the yield of conventional japonica rice and ensuring food security.展开更多
Bottom-up and top-down endogenous automobile clusters exhibit distinct evolutionary traits and driving mechanisms,yet their comparative analysis remains understudied.Therefore,using Taizhou automobile industry cluster...Bottom-up and top-down endogenous automobile clusters exhibit distinct evolutionary traits and driving mechanisms,yet their comparative analysis remains understudied.Therefore,using Taizhou automobile industry cluster(TAIC)and Wuhu automobile industry cluster(WAIC)as cases,using historical statistical data and field interview data from the 1980s to 2023,combined with qualitative research methods of thematic and diachronic analysis,and quantitative research methods of social network analysis,we compare both endogenous automobile clusters’evolutionary traits and driving mechanisms.The results confirm both clusters undergo multi-scale spatial reconfiguration,organizational complexification,and intelligent networking technological transformation,yet diverge fundamentally:TAIC evolves through market-driven progressive expansion,transitioning from single to dual-core structures via private enterprise networking,with innovation following market-integrated logic and institutional thickness built on demand-driven evolution.Conversely,WAIC follows planned expansion,maintaining state-led hierarchical single-core stability through policy-driven breakthrough innovation and supply-dominated institutional construction-though both ultimately require formal-informal system synergy.Their coevolution is driven by dynamic interactions of path dependence(weakening influence),learning-innovation(strengthening influence),and relationship selection(inverted U-shaped trajectory),with divergent development paths rooted in TAIC’s grassroots self-organization genes versus WAIC’s top-level design genes,amplified by core enterprises’strategic disparities.The research findings can not only provide decision-making support for China’s industrial upgrading,but also contribute China’s insights to global economic governance.展开更多
The cold chain environment is an important route for the long⁃distance transmission of pathogenic micro⁃organisms.In this study,we explored the mechanisms of secondary propagation through surface contact on cold surfa...The cold chain environment is an important route for the long⁃distance transmission of pathogenic micro⁃organisms.In this study,we explored the mechanisms of secondary propagation through surface contact on cold surfaces.A quantitative statistical experimental method was adopted to study the surface⁃contact transmission of micro⁃organisms,wherein the transfer rate of surface contact was the dependent variable and Escherichia coli was used as the indicator bacterium.The effects of contact pressure(0.44,0.86,1.55,2.25,and 2.94 N/cm^(2)),contact time(0,15,30,45,and 60 s),contact angle(15°and 25°),and surface materials(rubber and cotton gloves)were measured at two storage temperatures:cold storage(5℃)and freezing(-18℃).The results showed that as temperature decreases,the transfer of micro⁃organisms through surface contact becomes less probable.The contact time did not significantly influence the transfer rate of micro⁃organisms when items were handled at cold⁃storage temperatures.Based on these results,we recommend placing items as flat as possible to minimize the tilt angle when handling them at cold⁃storage temperatures.Additionally,if the tilt angle cannot be avoided,rubber gloves should be used when handling items stored at large tilt angles,whereas cotton gloves may be used for items placed at smaller angles.展开更多
The smart meter communication system has substantial application value for the construction and upgrading of the entire power system.The deployment of the transmitter(Tx)of the smart meter system in the residential sc...The smart meter communication system has substantial application value for the construction and upgrading of the entire power system.The deployment of the transmitter(Tx)of the smart meter system in the residential scenarios is vexed by the need for more theoretical support.This paper mainly studies the communication channel between the Tx at semibasement and receiver(Rx)at outdoor.The design of an effective communication system relies on an accurate understanding of channel characteristics.Channel measurements and ray-tracing channel modeling are conducted to obtain channel data.The influence of different positions at same semi-basement is studied.Typical channel characteristics are analyzed,such as power delay profile(PDP),power angular profile(PAP),root-mean-square(RMS)delay spread(DS),channel capacity,received power,and path loss.The influence of different semi-basement placements and different floor heights is also compared.Besides,the channel measurements and simulation data fit well,which can illustrate the validity and reliability of the acquired channel data.This paper can provide theoretical support for the design and optimization of smart meter communication systems in semi-basement scenarios.展开更多
The Ordos Basin is a large superimposed hydrocarbon-bearing basin in China,and further research on the sedimentary characteristics and sedimentary evolution of the sequence framework of target layers is of great theor...The Ordos Basin is a large superimposed hydrocarbon-bearing basin in China,and further research on the sedimentary characteristics and sedimentary evolution of the sequence framework of target layers is of great theoretical and practical significance for guiding oil and gas exploration.The sedimentary facies and sedimentary evolution of the high-resolution sequence framework of the Carboniferous Taiyuan Formation in the Hangjinqi area have been systematically analyzed for the first time by drilling,logging and seismic data.The results show that four types of sequence interfaces can be identified in the Taiyuan Formation:regional unconformity surfaces,scour surfaces,lithologic-lithofacies transformation surfaces and flooding surfaces.According to the sedimentary response caused by the upward and downward movements of the base level at different levels,the Taiyuan Formation can be divided into 2 long-term cycles(LSC_(1)-LSC_(2)),4 mid-term cycles(MSC_(1)-MSC4)and 7 short-term cycles(SSC_(1)-SSC7).The long-and mid-term cycles correspond to members T_(1)and T_(2)and layers T_(1)-1,T_(1-2),T_(2-1),and T_(2)-2,respectively.Long-term cycles are dominated by C_(1);mid-term cycles are dominated by C_(1)and C_(2),followed by A2;and short-term cycles are dominated by C_(1),C_(2),A1 and A2.Under the high-resolution sequence stratigraphic framework,the Hangjinqi area underwent a transformation of fan delta and tidal flat depositional systems during the Taiyuan Formation sedimentary period.In the MSC_(1)-MSC_(2)stage,owing to a large-scale paleocontinent,the fan delta sedimentary body,which was limited in scale and scope,developed only in the southeastern corner and gradually transitioned basinward to tidal flat facies.In the MSC3-MSC4 stage,as the paleocontinent continuously decreased and the sedimentary range expanded,fan-delta plain sedimentation began in the study area.Several braided distributary channels with poor connectivity developed on the fan-delta plain,and between them were floodplains and peat swamps.展开更多
The Ordovician Majiagou Formation(O1m)in the Ordos Basin is a crucial exploration field for natural gas,and exploration of the Ordovician middle assemblage(O_(1)m_(5)^(5-7))has recently yielded great breakthrough.The ...The Ordovician Majiagou Formation(O1m)in the Ordos Basin is a crucial exploration field for natural gas,and exploration of the Ordovician middle assemblage(O_(1)m_(5)^(5-7))has recently yielded great breakthrough.The Daniudi gas field provides a good case study to determine the gas source for the strata.The O_(1)m_(5)^(5-7)gas displays C1/C1-5 ratios of 0.932-0.985 and CO_(2)contents of 1.56%-11.75%,and the detectable H2S content ranges from 0.0002%to 1.8617%.Theδ^(13)C1,δ^(13)C2,δ^(13)CCO_(2),andδD_(1)values are−39.7‰to−35.6‰,−30.4‰to−23.7‰,−12.4‰to−4.6‰,and−204‰to−185‰,respectively.Identification of the gas origin and source indicates that the gaseous alkanes are commonly coal-derived gas.The gas was generated from the coal measures in the Taiyuan Formation(C_(3t))and subsequently migrated.A small amount of oil-associated gas,mainly from O1m carbonate source rocks,has been incorporated into the gas reservoir.The natural gas has experienced insignificant alteration by thermochemical sulfate reduction,and the relatively high levels of CO_(2)are probably associated with corrosion alteration of carbonate reservoirs by injected fluid during acid fracturing.展开更多
The Yili River Basin in Northwest China is a crucial ecological security barrier,yet it faces frequent droughts amid global climate change,posing significant threats to food security and ecological stability.However,t...The Yili River Basin in Northwest China is a crucial ecological security barrier,yet it faces frequent droughts amid global climate change,posing significant threats to food security and ecological stability.However,the spatiotemporal variations and driving mechanisms of drought in the basin remain unclear.Based on the monthly Standardized Precipitation Evapotranspiration Index(SPEI),this study employed the Run-Length theory to identify drought events in the basin during 1980-2020,applied statistical and time-series analyses to investigate the spatiotemporal variations,trends,periodicity,and persistence of drought,and explored the underlying drivers associated with meteorological factors and large-scale atmospheric circulation patterns.The results showed that droughts in the Yili River Basin are more severe in spring and summer.Droughts in the central and southwestern regions exhibit greater severity,with shorter durations and stronger intensity.Drought conditions have generally worsened(Sen’s slope=−0.146/10 yr),with notable intensification since 2005,especially in the northwestern region.Spring droughts(Sen’s slope=−0.213/10 yr)and summer droughts(Sen’s slope=−0.169/10 yr)have intensified at most stations,while autumn and winter droughts have eased.In the future,droughts are expected to alleviate overall,but summer droughts may continue to intensify.The Yili River Basin exhibits two primary drought periods of 9 yr and 21 yr,with primary periods in autumn(20 yr)and winter(20 yr)being longer than those in spring(10 yr)and summer(17 yr).Finally,droughts are impacted by both meteorological factors and large-scale atmospheric circulation patterns.Rising temperatures and uneven precipitation have intensified droughts.The SPEI exhibits a co-phase relationship with the North Atlantic Oscillation and an antiphase relationship with the East Central Tropical Pacific Sea Surface Temperature.Therefore,close monitoring and mitigation are necessary for spring and summer droughts,with a focus on the central and southwestern areas in autumn and winter.展开更多
Microglia,the resident immune cells of the central nervous system,exhibit a wide array of functional states,even in their so-called“homeostatic”condition,when they are not actively responding to overt pathological s...Microglia,the resident immune cells of the central nervous system,exhibit a wide array of functional states,even in their so-called“homeostatic”condition,when they are not actively responding to overt pathological stimuli.These functional states can be visualized using a combination of multi-omics techniques(e.g.,gene and protein expression,posttranslational modifications,mRNA profiling,and metabolomics),and,in the case of homeostatic microglia,are largely defined by the global(e.g.,genetic variations,organism’s age,sex,circadian rhythms,and gut microbiota)as well as local(specific area of the brain,immediate microglial surrounding,neuron-glia interactions and synaptic density/activity)signals(Paolicelli et al.,2022).While phenomics(i.e.,ultrastructural microglial morphology and motility)is also one of the key microglial state-defining parameters,it is known that cells with similar morphology can belong to different functional states.展开更多
0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,...0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,87.45°E,with a depth of~10 km.展开更多
To prepare a conductive polymer actuator with decent performance,a self-built experimental platform for the preparation of polypyrrole film is employed.One of the essential goals is to examine the mechanical character...To prepare a conductive polymer actuator with decent performance,a self-built experimental platform for the preparation of polypyrrole film is employed.One of the essential goals is to examine the mechanical characteristics of the actuator in the presence of various combinations of process parameters,combined with the orthogonal test method of"four factors and three levels".The bending and sensing characteristics of actuators of various sizes are methodically examined using a self-made bending polypyrrole actuator.The functional relationship between the bending displacement and the output voltage signal is established by studying the characteristics of the actuator sensor subjected to various degrees of bending.The experimental results reveal that the bending displacement of the actuator tip almost exhibits a linear variation as a function of length and width.When the voltage reaches 0.8 V,the bending speed of the actuator tends to be stable.Finally,the mechanical properties of the self-assembled polypyrrole actuator are verified by the design and fabrication of the microgripper.展开更多
The deformation characteristics of silty soils under vibrational loads can easily change due to the wetting process,leading to the failure of roadbed structures.Commonly used methods for improving silty soils in engin...The deformation characteristics of silty soils under vibrational loads can easily change due to the wetting process,leading to the failure of roadbed structures.Commonly used methods for improving silty soils in engineering often yield unsatisfactory economic and ecological outcomes.As an environment-friendly soil improvement material,Xanthan gum has broad application prospects and is therefore considered a solidifying agent for enhancing silty soil properties in the Yellow River Basin.In this study,a series of tests is conducted using a scanning electron microscope and a dynamic triaxial testing apparatus to investigate the microstructure and dynamic deformation characteristics of unsaturated silty soil with varying xanthan gum contents during the wetting process.The results show that xanthan gum effectively fills voids between soil particles and adheres to their surfaces,forming fibrous and network structures.This modification enhances the inherent properties of the silty soil and significantly improves its stability under dynamic loading.Specifically,with increasing xanthan gum content,the dynamic shear modulus increases while the damping ratio decreases.During the wetting process,as suction decreases,the dynamic shear modulus decreases while the damping ratio increases.Xanthan gum reduces the sensitivity of the dynamic deformation characteristics of the treated silty soil to changes in suction levels.Finally,based on the modified Hardin-Drnevich hyperbolic model,a predictive model for the dynamic shear modulus and damping ratio of treated silty soil is proposed,considering the xanthan gum content.These research findings provide a theoretical basis for the construction and maintenance of water conservancy,slope stabilization,and roadbed projects in the Yellow River Basin.展开更多
Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosyste...Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosystems.However,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain unclear.This study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–2020.Results indicated an annual mean WUE of 0.8088 gC/mm·m^(2)across the plateau,with a spatial gradient reflecting decrease from the southeast toward the northwest.Areas manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,respectively.Remarkably,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of increase.Environmental factors accounted for 70.79%of the variability in WUE.The leaf area index and temperature served as the major driving forces of WUE variation.展开更多
Background There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming,but these feedstuffs are fibrous in nature.This study investigated the relationship b...Background There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming,but these feedstuffs are fibrous in nature.This study investigated the relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization,energy metabolism,and gut microbiota in growing pigs.Methods Thirty-six growing barrows(47.2±1.5 kg)were randomly allotted to 6 dietary treatments with 2 apparent viscosity levels and 3β-glucan-to-arabinoxylan ratios.In the experiment,nutrient utilization,energy metabolism,fecal microbial community,and production and absorption of short-chain fatty acid(SCFA)of pigs were investigated.In vitro digestion and fermentation models were used to compare the fermentation characteristics of feedstuffs and ileal digesta in the pig’s hindgut.Results The production dynamics of SCFA and dry matter corrected gas production of different feedstuffs during in vitro fermentation were different and closely related to the physical properties and chemical structure of the fiber.In animal experiments,increasing the dietary apparent viscosity and theβ-glucan-to-arabinoxylan ratios both increased the apparent ileal digestibility(AID),apparent total tract digestibility(ATTD),and hindgut digestibility of fiber components while decreasing the AID and ATTD of dry matter and organic matter(P<0.05).In addition,increasing dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased gas exchange,heat production,and protein oxidation,and decreased energy deposition(P<0.05).The dietary apparent viscosity andβ-glucanto-arabinoxylan ratios had linear interaction effects on the digestible energy,metabolizable energy,retained energy(RE),and net energy(NE)of the diets(P<0.05).At the same time,the increase of dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased SCFA production and absorption(P<0.05).Increasing the dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios increased the diversity and abundance of bacteria(P<0.05)and the relative abundance of beneficial bacteria.Furthermore,increasing the dietaryβ-glucan-to-arabinoxylan ratios led to a linear increase in SCFA production during the in vitro fermentation of ileal digesta(P<0.001).Finally,the prediction equations for RE and NE were established.Conclusion Dietary fiber physicochemical properties alter dietary fermentation patterns and regulate nutrient utilization,energy metabolism,and pig gut microbiota composition and metabolites.展开更多
To enhance the operational capacity and space utilization of baffle-drop shafts,this study improved the traditional baffle-drop shaft by expanding the wet-side space,incorporating large rotation-angle baffles,and inst...To enhance the operational capacity and space utilization of baffle-drop shafts,this study improved the traditional baffle-drop shaft by expanding the wet-side space,incorporating large rotation-angle baffles,and installing overflow holes in the dividing wall.A three-dimensional turbulent model was developed using ANSYS Fluent to simulate the hydraulic characteristics of both traditional and new baffle-drop shafts across various flow rates.The simulation results demonstrated that the new shaft design allowed for discharge from both the wet and dry sides,significantly improving operational capacity,with the dry side capable of handling 40%of the inlet flow.Compared to the traditional shaft,the new design reduced shaft wall pressures and decreased the mean and standard deviation of pressure on typical baffles by 21%and 63%,respectively,therefore enhancing structural safety.Additionally,the new shaft achieved a 2%-12%higher energy dissipation rate than the traditional shaft across different flow rates.This study offers valuable insights for the design and optimization of drop shafts in deep tunnel drainage systems.展开更多
Based on comprehensive observations of 20 wire icing events during winter from 2019 to 2021,we investigated the characteristics of the icing properties,the atmospheric boundary layer structure,the raindrop size distri...Based on comprehensive observations of 20 wire icing events during winter from 2019 to 2021,we investigated the characteristics of the icing properties,the atmospheric boundary layer structure,the raindrop size distribution,and their associated effects on the ice accretion mechanism in the mountainous region of Southwest China.The maximum ice weight was positively correlated with the duration of ice accretion in the mountainous area.The duration of precipitation accounted for less than 20%of the icing period in the mountainous area,with solid-phase hydrometeors being predominant.Icing events,dominated by freezing rain(FR)and mixed rain–graupel(more than 70%),were characterized by glaze or highdensity mixed icing.The relationship between the melting energy and refreezing energy reflected the distribution characteristics of the proportion of FR under mixed-phase precipitation.The intensity of the warm layer and the dominant precipitation phase significantly affected the variations in the microphysical properties of FR.The melting of large dry snowflakes significantly contributed to FR in the mountainous areas,resulting in smaller generalized intercepts and larger mass-weighted mean diameters in the presence of a stronger warm layer.Under a weaker warm layer,the value of the massweighted mean diameter was significantly smaller because of the inability of large solid particles to melt.Finally,FR in the mountainous area dominated the ice weight during the rapid ice accumulation period.A numerical simulation of FR icing on wires effectively revealed the evolution of disaster-causing icing in mountainous areas.展开更多
文摘Standardization is necessary for the early industrialization of the new materials and technology.It is achieved by having agreed practices for the measurement of properties and other characteristics.The promising use of graphene-based materials in fields like electronics,energy,and composites has resulted in standards for their nomenclature,the measurement of key characteristics,and their specification,etc.Among these,standards for measuring the key characteristics are crucial.The critical parameters are the number of layers,the type and concentration of defects and functional groups,elemental composition,sheet resistance,and carrier mobility.Standards for characterizing these have been analyzed by the International Organization for Standardization Technical Committee in ISO/TC229 and the International Electrotechnical Commission Technical Committee in IEC/TC113.These give details of applicable or preferred samples,the fundamental principles of the techniques,specific precautions,and points for attention in the relevant standards.The pivotal role of the ISO/TC229 and IEC/TC113 standards is considered and challenges and future trends are outlined.
文摘39 soil samples surrounding a lead-zinc mining area in Guangxi were collected,and the contents of Pb,Hg,Cd,Cr,As,Cu,Zn,and Ni were determined to investigate the pollution characteristics and sources of heavy metals.ArcGIS inverse distance weight difference method was used to analyze the characteristics of pollution distribution,and single-factor pollution index,Nemerow comprehensive pollution index,ground accumulation index,and potential ecological risk index were selected to evaluate the characteristics of heavy metal pollution.Based on correlation analysis,the absolute principal component-multiple linear regression(APCS-MLR)and positive definite matrix factorization(PMF)models were used to analyze the sources of soil heavy metals.The results showed that the average concentrations of all eight heavy metals exceeded both national and Guangxi soil background values.Hg,Cd,and Zn exhibited high variation(greater than 0.5),indicating significant external disturbances,and their spatial distribution was closely related to mining activity locations.The single-factor pollution index evaluation indicated varying degrees of pollution risk for Cd,Zn,and As,with Cd and Zn being the most severe pollutants,as 69.23%and 30.77%of the samples fell into the moderate pollution or higher category.The geoaccumulation index analysis ranked the mean pollution levels of the eight elements as follows:Zn>Cd>Ni>Pb>Cu>Cr>Hg>As,with Cd and Zn showing the most severe contamination,and 51.28%of the samples exhibiting moderate or higher pollution levels.The Nemerow comprehensive pollution index evaluation showed that 74.35%of soil samples were classified as moderate to heavy pollution.The potential ecological risk index assessment indicated significant ecological risks posed by Cd and Zn,with 82.05%and 5.12%of the samples classified as causing strong to extreme ecological risks,respectively.The source apportionment analysis revealed minor differences between the two models.The APCS-MLR model identified three pollution sources and their contribution rates:anthropogenic mining sources(31.13%),parent material sources(40.38%),and unidentified sources(28.49%).The PMF model identified three pollution sources with contribution rates of anthropogenic mining sources(26.10%),parent material sources(46.96%),and a combined traffic and agricultural source(26.61%).Pb,Hg,Cd,and Zn mainly originated from mining activities;Cr,As,and Ni were primarily derived from the parent material,while Cu was predominantly attributed to traffic and agricultural sources.These findings provide a scientific basis for the prevention and control of heavy metal pollution in mining areas.
基金supported by National Natural Science Foundation of China(Grant Nos.52364004 and 52264006)The Youth Talent Growth Project of Guizhou Provincial Department of Education(Grant No.QianJiaoJi[2024]18).
文摘Extensive engineering experience and research findings suggest that rock mass instability is typically attributed to human engineering activities and natural disturbances,resulting in general dynamic mechanical properties.This is attributed to external interference resulting from the extensive use of the mechanical and blasting techniques necessary for mineral extraction.Quantifying the impact of dynamic disturbances on rock deformation behavior is essential for comprehending the long-term response of surrounding rock during excavation.This study placed the rock to sustained pressure and investigated the impact of varying hammer heights and dry and wet(W-D)damage on its shear failure behavior.This study investigated the fatigue disturbance studies on W-D damaged sandstone samples via W-D equipment,a disturbance creep device,digital image correlation(DIC),and acoustic emission(AE)technology.The experimental findings suggest that acoustic emission sensors can be utilized to quantify the internal damage of rock samples during cyclic impact,whereas DIC technology(optical measurement)is capable of capturing the surface crack propagation of samples.Under repeated impact and the combined action of W-D conditions,the bearing capacity of sandstone decreases,whereas the deformation capacity increases.Furthermore,the W-D cycles and impact strength are inversely related to the fatigue life.The intensity of W-D damage and disturbances further accelerates the development and propagation of cracks under cyclic disturbances.The research results are of preventive significance to ensure the safety and sustainable development of engineering construction.
基金supported by the National Natural Science Foundation of China(Nos.62375144 and 12404345)"the Fundamental Research Funds for the Central Universities",Nankai University(No.63241331).
文摘Accurate and early evaluation of dental physiological characteristics is essential for effective disease detection and management.Polarization-sensitive optical coherence tomography(PS-OCT)is a noninvasive high-resolution imaging technique that can obtain tooth structure and physiological features through intensity,retardation and degree of polarization uniformity(DOPU)images.In this study,we use the information provided by the PS-OCT system,especially the retardation information,to assess the physiological characteristics of teeth.In addition,we introduce a novel parameter—the rate of change of the retardation value(R)—to evaluate the magnitude of birefringence of enamel,which serves as an indicator of enamel health and mineralization.The results demonstrate that PS-OCT not only provides structural detail comparable to microcomputed tomography(microCT),but also yields additional physiological characteristics insights through polarization-based contrast.These findings highlight the strong potential of PS-OCT for early diagnosis,functional evaluation and personalized monitoring in dental care.
基金funded by the National Key R&D Program of China (Grant No. 2024YFD2300301)the National Natural Science Foundation of China (Grant Nos. 32472223 and 31901447)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Qinglan Project of Jiangsu Province, China
文摘Clarifying the photosynthetic and population characteristics of conventional japonica rice at different yield levels is crucial for boosting yield and ensuring food security.Therefore,a two-year field trial with two conventional japonica varieties was conducted at four planting densities:16 cm×30 cm(D1),14 cm×30 cm(D2),12 cm×30 cm(D3),and 10 cm×30 cm(D4).This study aimed to investigate how photosynthetic and population characteristics influence grain yield under varying planting densities.The results indicated that higher yields were primarily driven by increased grain weight and seed-setting rate(with a 9.68%‒11.40%higher single panicle weight),supported by optimized dry matter translocation and source-sink relationships.Elevated planting density(D2‒D4)enhanced panicle number and total spikelet number(by 3.91%‒15.00%)but reduced the number of spikelets per panicle,1000-grain weight,and photosynthetic efficiency due to mutual shading.Despite these trade-offs,yield increased by 4.10%‒12.42%under higher densities.The use of planting density D4 in japonica rice cultivation contributed to maximize yield.These findings provide important theoretical insights and practical significance for increasing the yield of conventional japonica rice and ensuring food security.
基金Under the auspices of National Natural Science Foundation of China(No.42571219)Key Project of Zhejiang Province Soft Science Research Plan(No.2023C25014)。
文摘Bottom-up and top-down endogenous automobile clusters exhibit distinct evolutionary traits and driving mechanisms,yet their comparative analysis remains understudied.Therefore,using Taizhou automobile industry cluster(TAIC)and Wuhu automobile industry cluster(WAIC)as cases,using historical statistical data and field interview data from the 1980s to 2023,combined with qualitative research methods of thematic and diachronic analysis,and quantitative research methods of social network analysis,we compare both endogenous automobile clusters’evolutionary traits and driving mechanisms.The results confirm both clusters undergo multi-scale spatial reconfiguration,organizational complexification,and intelligent networking technological transformation,yet diverge fundamentally:TAIC evolves through market-driven progressive expansion,transitioning from single to dual-core structures via private enterprise networking,with innovation following market-integrated logic and institutional thickness built on demand-driven evolution.Conversely,WAIC follows planned expansion,maintaining state-led hierarchical single-core stability through policy-driven breakthrough innovation and supply-dominated institutional construction-though both ultimately require formal-informal system synergy.Their coevolution is driven by dynamic interactions of path dependence(weakening influence),learning-innovation(strengthening influence),and relationship selection(inverted U-shaped trajectory),with divergent development paths rooted in TAIC’s grassroots self-organization genes versus WAIC’s top-level design genes,amplified by core enterprises’strategic disparities.The research findings can not only provide decision-making support for China’s industrial upgrading,but also contribute China’s insights to global economic governance.
基金National Natural Science Foundation of China(Grant No.52278121).
文摘The cold chain environment is an important route for the long⁃distance transmission of pathogenic micro⁃organisms.In this study,we explored the mechanisms of secondary propagation through surface contact on cold surfaces.A quantitative statistical experimental method was adopted to study the surface⁃contact transmission of micro⁃organisms,wherein the transfer rate of surface contact was the dependent variable and Escherichia coli was used as the indicator bacterium.The effects of contact pressure(0.44,0.86,1.55,2.25,and 2.94 N/cm^(2)),contact time(0,15,30,45,and 60 s),contact angle(15°and 25°),and surface materials(rubber and cotton gloves)were measured at two storage temperatures:cold storage(5℃)and freezing(-18℃).The results showed that as temperature decreases,the transfer of micro⁃organisms through surface contact becomes less probable.The contact time did not significantly influence the transfer rate of micro⁃organisms when items were handled at cold⁃storage temperatures.Based on these results,we recommend placing items as flat as possible to minimize the tilt angle when handling them at cold⁃storage temperatures.Additionally,if the tilt angle cannot be avoided,rubber gloves should be used when handling items stored at large tilt angles,whereas cotton gloves may be used for items placed at smaller angles.
基金supported by the Natural Science Foundation of Shandong Province under Grant ZR2024MF062the open research fund of National Mobile Communications Research Laboratory,Southeast University under Grants 2025D03+1 种基金the Future Plan Program for Young Scholars of Shandong University,and the Innovation and Technology Support Program for Young Scholars of Colleges and Universities in Shandong Province under Grant 2022KJ009The B6G R&D Group in Shandong University is greatly thanked for channel measurements.
文摘The smart meter communication system has substantial application value for the construction and upgrading of the entire power system.The deployment of the transmitter(Tx)of the smart meter system in the residential scenarios is vexed by the need for more theoretical support.This paper mainly studies the communication channel between the Tx at semibasement and receiver(Rx)at outdoor.The design of an effective communication system relies on an accurate understanding of channel characteristics.Channel measurements and ray-tracing channel modeling are conducted to obtain channel data.The influence of different positions at same semi-basement is studied.Typical channel characteristics are analyzed,such as power delay profile(PDP),power angular profile(PAP),root-mean-square(RMS)delay spread(DS),channel capacity,received power,and path loss.The influence of different semi-basement placements and different floor heights is also compared.Besides,the channel measurements and simulation data fit well,which can illustrate the validity and reliability of the acquired channel data.This paper can provide theoretical support for the design and optimization of smart meter communication systems in semi-basement scenarios.
基金supported by the Fundamental Research Funds for the Liaoning Universities(Grant No.LJ202410166012).
文摘The Ordos Basin is a large superimposed hydrocarbon-bearing basin in China,and further research on the sedimentary characteristics and sedimentary evolution of the sequence framework of target layers is of great theoretical and practical significance for guiding oil and gas exploration.The sedimentary facies and sedimentary evolution of the high-resolution sequence framework of the Carboniferous Taiyuan Formation in the Hangjinqi area have been systematically analyzed for the first time by drilling,logging and seismic data.The results show that four types of sequence interfaces can be identified in the Taiyuan Formation:regional unconformity surfaces,scour surfaces,lithologic-lithofacies transformation surfaces and flooding surfaces.According to the sedimentary response caused by the upward and downward movements of the base level at different levels,the Taiyuan Formation can be divided into 2 long-term cycles(LSC_(1)-LSC_(2)),4 mid-term cycles(MSC_(1)-MSC4)and 7 short-term cycles(SSC_(1)-SSC7).The long-and mid-term cycles correspond to members T_(1)and T_(2)and layers T_(1)-1,T_(1-2),T_(2-1),and T_(2)-2,respectively.Long-term cycles are dominated by C_(1);mid-term cycles are dominated by C_(1)and C_(2),followed by A2;and short-term cycles are dominated by C_(1),C_(2),A1 and A2.Under the high-resolution sequence stratigraphic framework,the Hangjinqi area underwent a transformation of fan delta and tidal flat depositional systems during the Taiyuan Formation sedimentary period.In the MSC_(1)-MSC_(2)stage,owing to a large-scale paleocontinent,the fan delta sedimentary body,which was limited in scale and scope,developed only in the southeastern corner and gradually transitioned basinward to tidal flat facies.In the MSC3-MSC4 stage,as the paleocontinent continuously decreased and the sedimentary range expanded,fan-delta plain sedimentation began in the study area.Several braided distributary channels with poor connectivity developed on the fan-delta plain,and between them were floodplains and peat swamps.
基金sponsored by National Natural Science Foundation of China(Grant Nos.U2244209,42172149,42488101,and 42141021).
文摘The Ordovician Majiagou Formation(O1m)in the Ordos Basin is a crucial exploration field for natural gas,and exploration of the Ordovician middle assemblage(O_(1)m_(5)^(5-7))has recently yielded great breakthrough.The Daniudi gas field provides a good case study to determine the gas source for the strata.The O_(1)m_(5)^(5-7)gas displays C1/C1-5 ratios of 0.932-0.985 and CO_(2)contents of 1.56%-11.75%,and the detectable H2S content ranges from 0.0002%to 1.8617%.Theδ^(13)C1,δ^(13)C2,δ^(13)CCO_(2),andδD_(1)values are−39.7‰to−35.6‰,−30.4‰to−23.7‰,−12.4‰to−4.6‰,and−204‰to−185‰,respectively.Identification of the gas origin and source indicates that the gaseous alkanes are commonly coal-derived gas.The gas was generated from the coal measures in the Taiyuan Formation(C_(3t))and subsequently migrated.A small amount of oil-associated gas,mainly from O1m carbonate source rocks,has been incorporated into the gas reservoir.The natural gas has experienced insignificant alteration by thermochemical sulfate reduction,and the relatively high levels of CO_(2)are probably associated with corrosion alteration of carbonate reservoirs by injected fluid during acid fracturing.
基金Under the auspices of the Third Xinjiang Scientific Expedition Program(No.2022xjkk0600)。
文摘The Yili River Basin in Northwest China is a crucial ecological security barrier,yet it faces frequent droughts amid global climate change,posing significant threats to food security and ecological stability.However,the spatiotemporal variations and driving mechanisms of drought in the basin remain unclear.Based on the monthly Standardized Precipitation Evapotranspiration Index(SPEI),this study employed the Run-Length theory to identify drought events in the basin during 1980-2020,applied statistical and time-series analyses to investigate the spatiotemporal variations,trends,periodicity,and persistence of drought,and explored the underlying drivers associated with meteorological factors and large-scale atmospheric circulation patterns.The results showed that droughts in the Yili River Basin are more severe in spring and summer.Droughts in the central and southwestern regions exhibit greater severity,with shorter durations and stronger intensity.Drought conditions have generally worsened(Sen’s slope=−0.146/10 yr),with notable intensification since 2005,especially in the northwestern region.Spring droughts(Sen’s slope=−0.213/10 yr)and summer droughts(Sen’s slope=−0.169/10 yr)have intensified at most stations,while autumn and winter droughts have eased.In the future,droughts are expected to alleviate overall,but summer droughts may continue to intensify.The Yili River Basin exhibits two primary drought periods of 9 yr and 21 yr,with primary periods in autumn(20 yr)and winter(20 yr)being longer than those in spring(10 yr)and summer(17 yr).Finally,droughts are impacted by both meteorological factors and large-scale atmospheric circulation patterns.Rising temperatures and uneven precipitation have intensified droughts.The SPEI exhibits a co-phase relationship with the North Atlantic Oscillation and an antiphase relationship with the East Central Tropical Pacific Sea Surface Temperature.Therefore,close monitoring and mitigation are necessary for spring and summer droughts,with a focus on the central and southwestern areas in autumn and winter.
基金supported by Deutsche Forschungsgemeinschaft,German Research Foundation grant GA 654/13-2 to OG.
文摘Microglia,the resident immune cells of the central nervous system,exhibit a wide array of functional states,even in their so-called“homeostatic”condition,when they are not actively responding to overt pathological stimuli.These functional states can be visualized using a combination of multi-omics techniques(e.g.,gene and protein expression,posttranslational modifications,mRNA profiling,and metabolomics),and,in the case of homeostatic microglia,are largely defined by the global(e.g.,genetic variations,organism’s age,sex,circadian rhythms,and gut microbiota)as well as local(specific area of the brain,immediate microglial surrounding,neuron-glia interactions and synaptic density/activity)signals(Paolicelli et al.,2022).While phenomics(i.e.,ultrastructural microglial morphology and motility)is also one of the key microglial state-defining parameters,it is known that cells with similar morphology can belong to different functional states.
基金funded by the National Key R&D Program of China(No.2020YFC150071)partly supported by the Shaanxi Province Geoscience Big Data and Geohazard Prevention Innovation Team(2022)and the Research Funds for the Interdisciplinary Projects,CHU(No.300104240914)。
文摘0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,87.45°E,with a depth of~10 km.
基金Funded by the National Natural Science Foundation of Hunan Province,Chinal(No.2021JJ60012)。
文摘To prepare a conductive polymer actuator with decent performance,a self-built experimental platform for the preparation of polypyrrole film is employed.One of the essential goals is to examine the mechanical characteristics of the actuator in the presence of various combinations of process parameters,combined with the orthogonal test method of"four factors and three levels".The bending and sensing characteristics of actuators of various sizes are methodically examined using a self-made bending polypyrrole actuator.The functional relationship between the bending displacement and the output voltage signal is established by studying the characteristics of the actuator sensor subjected to various degrees of bending.The experimental results reveal that the bending displacement of the actuator tip almost exhibits a linear variation as a function of length and width.When the voltage reaches 0.8 V,the bending speed of the actuator tends to be stable.Finally,the mechanical properties of the self-assembled polypyrrole actuator are verified by the design and fabrication of the microgripper.
基金supported by the Postgraduate Education Reform and Quality Improvement Project of Henan Province,China(Grant No.YJS2023AL004)the Graduate Innovation Project of North China University of Water Resources and Electric Power(Grant No.NCWUYC-202315069)the China National Scholarship Fund organized by the China Scholarship Council(Grant No.202208410337).
文摘The deformation characteristics of silty soils under vibrational loads can easily change due to the wetting process,leading to the failure of roadbed structures.Commonly used methods for improving silty soils in engineering often yield unsatisfactory economic and ecological outcomes.As an environment-friendly soil improvement material,Xanthan gum has broad application prospects and is therefore considered a solidifying agent for enhancing silty soil properties in the Yellow River Basin.In this study,a series of tests is conducted using a scanning electron microscope and a dynamic triaxial testing apparatus to investigate the microstructure and dynamic deformation characteristics of unsaturated silty soil with varying xanthan gum contents during the wetting process.The results show that xanthan gum effectively fills voids between soil particles and adheres to their surfaces,forming fibrous and network structures.This modification enhances the inherent properties of the silty soil and significantly improves its stability under dynamic loading.Specifically,with increasing xanthan gum content,the dynamic shear modulus increases while the damping ratio decreases.During the wetting process,as suction decreases,the dynamic shear modulus decreases while the damping ratio increases.Xanthan gum reduces the sensitivity of the dynamic deformation characteristics of the treated silty soil to changes in suction levels.Finally,based on the modified Hardin-Drnevich hyperbolic model,a predictive model for the dynamic shear modulus and damping ratio of treated silty soil is proposed,considering the xanthan gum content.These research findings provide a theoretical basis for the construction and maintenance of water conservancy,slope stabilization,and roadbed projects in the Yellow River Basin.
基金National Nonprofit Institute Research Grant of CAF,No.CAFYBB2018ZA004,No.CAFYBB2023ZA009Fengyun Application Pioneering Project,No.FY-APP-ZX-2023.02。
文摘Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosystems.However,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain unclear.This study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–2020.Results indicated an annual mean WUE of 0.8088 gC/mm·m^(2)across the plateau,with a spatial gradient reflecting decrease from the southeast toward the northwest.Areas manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,respectively.Remarkably,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of increase.Environmental factors accounted for 70.79%of the variability in WUE.The leaf area index and temperature served as the major driving forces of WUE variation.
基金supported by the National Key Research and Development Program(No.2021YFD1300201)Jilin Provincial Department of Science and Technology Innovation Platform and Talent Special Project(No.20230508090RC).
文摘Background There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming,but these feedstuffs are fibrous in nature.This study investigated the relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization,energy metabolism,and gut microbiota in growing pigs.Methods Thirty-six growing barrows(47.2±1.5 kg)were randomly allotted to 6 dietary treatments with 2 apparent viscosity levels and 3β-glucan-to-arabinoxylan ratios.In the experiment,nutrient utilization,energy metabolism,fecal microbial community,and production and absorption of short-chain fatty acid(SCFA)of pigs were investigated.In vitro digestion and fermentation models were used to compare the fermentation characteristics of feedstuffs and ileal digesta in the pig’s hindgut.Results The production dynamics of SCFA and dry matter corrected gas production of different feedstuffs during in vitro fermentation were different and closely related to the physical properties and chemical structure of the fiber.In animal experiments,increasing the dietary apparent viscosity and theβ-glucan-to-arabinoxylan ratios both increased the apparent ileal digestibility(AID),apparent total tract digestibility(ATTD),and hindgut digestibility of fiber components while decreasing the AID and ATTD of dry matter and organic matter(P<0.05).In addition,increasing dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased gas exchange,heat production,and protein oxidation,and decreased energy deposition(P<0.05).The dietary apparent viscosity andβ-glucanto-arabinoxylan ratios had linear interaction effects on the digestible energy,metabolizable energy,retained energy(RE),and net energy(NE)of the diets(P<0.05).At the same time,the increase of dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios both increased SCFA production and absorption(P<0.05).Increasing the dietary apparent viscosity andβ-glucan-to-arabinoxylan ratios increased the diversity and abundance of bacteria(P<0.05)and the relative abundance of beneficial bacteria.Furthermore,increasing the dietaryβ-glucan-to-arabinoxylan ratios led to a linear increase in SCFA production during the in vitro fermentation of ileal digesta(P<0.001).Finally,the prediction equations for RE and NE were established.Conclusion Dietary fiber physicochemical properties alter dietary fermentation patterns and regulate nutrient utilization,energy metabolism,and pig gut microbiota composition and metabolites.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFD1700802).
文摘To enhance the operational capacity and space utilization of baffle-drop shafts,this study improved the traditional baffle-drop shaft by expanding the wet-side space,incorporating large rotation-angle baffles,and installing overflow holes in the dividing wall.A three-dimensional turbulent model was developed using ANSYS Fluent to simulate the hydraulic characteristics of both traditional and new baffle-drop shafts across various flow rates.The simulation results demonstrated that the new shaft design allowed for discharge from both the wet and dry sides,significantly improving operational capacity,with the dry side capable of handling 40%of the inlet flow.Compared to the traditional shaft,the new design reduced shaft wall pressures and decreased the mean and standard deviation of pressure on typical baffles by 21%and 63%,respectively,therefore enhancing structural safety.Additionally,the new shaft achieved a 2%-12%higher energy dissipation rate than the traditional shaft across different flow rates.This study offers valuable insights for the design and optimization of drop shafts in deep tunnel drainage systems.
基金funded by the National Natural Science Foundation of China(Grant No.42325503)the Hubei Provincial Natural Science Foundation and the Meteorological Innovation and Development Project of China(Grant Nos.2023AFD096 and 2022CFD122)+1 种基金the Natural Science Foundation of Wuhan(Grant No.2024020901030454)the Beijige Foundation of NJIAS(Grant No.BJG202304)。
文摘Based on comprehensive observations of 20 wire icing events during winter from 2019 to 2021,we investigated the characteristics of the icing properties,the atmospheric boundary layer structure,the raindrop size distribution,and their associated effects on the ice accretion mechanism in the mountainous region of Southwest China.The maximum ice weight was positively correlated with the duration of ice accretion in the mountainous area.The duration of precipitation accounted for less than 20%of the icing period in the mountainous area,with solid-phase hydrometeors being predominant.Icing events,dominated by freezing rain(FR)and mixed rain–graupel(more than 70%),were characterized by glaze or highdensity mixed icing.The relationship between the melting energy and refreezing energy reflected the distribution characteristics of the proportion of FR under mixed-phase precipitation.The intensity of the warm layer and the dominant precipitation phase significantly affected the variations in the microphysical properties of FR.The melting of large dry snowflakes significantly contributed to FR in the mountainous areas,resulting in smaller generalized intercepts and larger mass-weighted mean diameters in the presence of a stronger warm layer.Under a weaker warm layer,the value of the massweighted mean diameter was significantly smaller because of the inability of large solid particles to melt.Finally,FR in the mountainous area dominated the ice weight during the rapid ice accumulation period.A numerical simulation of FR icing on wires effectively revealed the evolution of disaster-causing icing in mountainous areas.
