Understanding the bubble behaviours and flow characteristics of large-capacity bottom-blowing electric arc furnace(EAF)is crucial for potential exogenous gas-induced slag foaming process and enhancement of molten bath...Understanding the bubble behaviours and flow characteristics of large-capacity bottom-blowing electric arc furnace(EAF)is crucial for potential exogenous gas-induced slag foaming process and enhancement of molten bath dynamics.A physical model and a 3D gas-slag-steel transient bottom-blowing numerical model of a 150 t EAF were established to investigate the bubble behaviour and flow characteristics throughout the molten steel bath and slag layer under bottom-blowing,with referring to gas flow rate,plug diameter,plug arrangement and injection angle.Results indicate that the average bubble sizes experience increase,dynamic stability and decrease in molten steel bath and then undergo decrease and increase after entering into slag layer for all bottom-blowing modes.The bubble numbers exhibit the opposing trends during the process.Increase in gas flow rate leads to a significant rise in average bubble size but a decrease in number,average dwelling time and the spread area of bubbles in slag layer.Increase in plug diameter causes an opposite impact.The effect of plug arrangement radii on bubbles is almost negligible.Increasing the injection angle results in an increase in bubble size and a decrease in both bubble number and dwelling time in slag layer.The slag foaming potential was discussed referring to the bubble size,number and dwelling time in slag layer.Increase in gas flow rate and plug diameters can significantly enhance the fluids flow through increasing average flow velocity,decreasing mixing time and dead zone ratio of molten bath.Plug arrangement radius and injection angle express nonlinear correlation with average flow velocity and dead zone ratio,and the plug arrangement radius of 0.5R(R represents the radius of bottom circle of EAF model)and injection angle of 15°perform better in enhancing dynamics of molten bath.A group of bottom-blowing parameters are proposed to achieve better comprehensive performance of bubble-induced slag foaming and molten bath dynamics.展开更多
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
The dependence of shrinkage porosities on microstructure characteristics of Mg−12Al alloy was investigated.The distribution,morphology,size,and number density of shrinkage porosities were analyzed under different cool...The dependence of shrinkage porosities on microstructure characteristics of Mg−12Al alloy was investigated.The distribution,morphology,size,and number density of shrinkage porosities were analyzed under different cooling rates.The relationship between shrinkage porosities and microstructure characteristics was discussed in terms of temperature conditions,feeding channel characteristics,and feeding capacity.Further,the feeding behavior of the residual liquid phase in the solid skeleton was quantified by introducing permeability.Results show a strong correlation between the solid microstructure skeleton and shrinkage porosity characteristics.An increase in permeability corresponds to a declining number density of shrinkage porosities.This study aims to provide a more complete understanding how to reduce shrinkage porosities by controlling microstructure characteristics.展开更多
This paper develops a method of characteristics for supersonic viscous flows.The proposed method removes the inviscid and isentropic assumptions of the classical method of characteristics.The characteristic equations ...This paper develops a method of characteristics for supersonic viscous flows.The proposed method removes the inviscid and isentropic assumptions of the classical method of characteristics.The characteristic equations and compatibility equations are derived from the governing equations for compressible viscous flow.By combining the characteristic lines,the triangular interior unit process,quadrilateral interior unit process,and direct sonic point unit process are developed.The unit processes make up the characteristic net.The numerical algorithms consider the path of flow signal propagation.The inviscid terms are solved along characteristic lines,while the viscous terms are corrected through iterative whole-field computations.The proposed method has been applied to supersonic flat-plate boundary layer and verified by the similarity solution.The errors of velocity and temperature profiles are on the order of 0.1%,while the computation efficiency is the same as the classical method of characteristics.The accuracy and efficiency make the proposed method potential to become a basic tool of analysis and design for supersonic viscous flows.展开更多
Metal organic framework(MOF) assembled with coordination bonds has the disadvantage of poor stability that limits its application in the field of stationary phase,while covalent organic framework(COF)assembled through...Metal organic framework(MOF) assembled with coordination bonds has the disadvantage of poor stability that limits its application in the field of stationary phase,while covalent organic framework(COF)assembled through covalent bonds exhibits excellent structural stability.It has been shown that the stationary phases prepared by combining MOF and COF can make up for the poor stability of MOF@SiO_(2),and the MOF/COF composites have superior chromatographic separation performance.However,the traditional methods for preparing COF/MOF based stationary phases are generally solvent thermal synthesis.In this study,a green and low-cost synthesis method was proposed for the preparation of MOF/COF@SiO_(2) stationary phase.Firstly,COF@SiO_(2) was prepared in a choline chloride/ethylene glycol based deep eutectic solvent(DES).Secondly,another acid-base tunable DES prepared by mixing p-toluenesulfonic acid(PTSA)and 2-methylimidazole in different proportions was introduced as the reaction solvent and reactant for rapid synthesis of MOF/COF@SiO_(2).Compared with the toxic transition metal-based MOFs selected in most previous studies,a lightweight and non-toxic S-zone metal(calcium) based MOF was employed in this study.PTSA and calcium will form the calcium/oxygen-containing organic acid framework in acidic DES,which assembles with terephthalic acid dissolved in basic DES to form MOF.The strong hydrogen bonding effect of DES can facilitate rapid assembly of Ca-MOF.The obtained Ca-MOF/COF@SiO_(2) can be used for multi-mode chromatography to efficiently separate multiple isomeric/hydrophilic/hydrophobic analytes.The synthesis method of Ca-MOF/COF@SiO_(2) is green and mild,especially the use of acid-base tunable DES promotes the rapid synthesis of non-toxic Ca-MOF/COF@silica composites,which offers an innovative approach of greenly synthesizing novel MOF/COF stationary phases and extends their applications in the field of chromatography.展开更多
The respiratory-circulatory system, including organs such as the nose, pharynx, larynx, trachea, bronchi, and heart, is an organic community responsible for ventilation and gas exchange. The integrity of its anatomica...The respiratory-circulatory system, including organs such as the nose, pharynx, larynx, trachea, bronchi, and heart, is an organic community responsible for ventilation and gas exchange. The integrity of its anatomical structure directly affects the evolution of pathological processes, and the analysis of their correlation is a core entry point for clinical disease diagnosis, treatment, and mechanism research. Based on this, this paper mainly explores the correlation between the anatomical and pathological characteristics of the respiratory-circulatory system, aiming to provide anatomical and pathological theoretical support for clinical accurate diagnosis, targeted therapy, and prognosis evaluation.展开更多
The soft actuator is characterized by high safety,flexibility,and adaptability.It is capable of both active and passive defor-mations.This paper presents a discrete degree of freedom(DOF)method for soft actuators to r...The soft actuator is characterized by high safety,flexibility,and adaptability.It is capable of both active and passive defor-mations.This paper presents a discrete degree of freedom(DOF)method for soft actuators to reveal DOF characteristics.The method draws on the superposition mechanism of the deformation characteristics of the sarcomere in the skeletal muscles of living organisms.Firstly,the multi-DOF deformation characteristics of the soft actuator are discretized into superimposed combinations of single-DOF micro-units.Then,the soft actuator was determined to contain deformation characteristics such as extension-contraction,bending,and twisting.Eighteen types of micro-units with basic deforma-tion characteristics were obtained depending on the axis and orientation.Further,the mapping relationship between the combination of micro-units and the motion characteristics of the soft actuator based on the GF set theory was established.Finally,an active-passive DOF co-structured soft actuator(APCSA)was developed.The graphical approach analyzes the experimental results,and it can be concluded that active and passive DOFs can coexist in the composite deformation of the soft actuator.展开更多
The flow behavior of molten steel in the thin slab mold under high casting speed conditions was investigated,with a focus on the multi-mode continuous casting and rolling mold.A steel-slag two-phase flow model was est...The flow behavior of molten steel in the thin slab mold under high casting speed conditions was investigated,with a focus on the multi-mode continuous casting and rolling mold.A steel-slag two-phase flow model was established using large eddy simulation,the volume of fluid,and magnetohydrodynamics methods through numerical simulation.The maximum flow velocity and wave height at the steel-slag interface within the mold are critical evaluation criteria for analyzing asymmetric flow under varying casting speeds and electromagnetic braking.The results indicate that the asymmetric flows within the mold do not occur synchronously.The severity of the asymmetric flow correlates with the velocity difference across the steel-slag interface.A greater biased flow prolongs the time required to revert to a steady state.When the magnetic field intensity is set to 0.24 T and the magnetic pole position is at 390 mm from the steel-slag interface,this configuration can reduce the velocity of the steel-slag interface,thereby mitigating the asymmetric flow.Additionally,it can diminish the velocity,impact depth,and impact intensity on the narrow face of the jet,thus improving the distribution of velocity and turbulent kinetic energy within the mold.This configuration prolongs the time required for the steel-slag interface to transition from a stable state to its maximum velocity and shortens the time for the interface to return to stability from an unstable state.Moreover,it ensures the positional stability of the steel-slag interface,confining its position within−3 mm.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
The cosmetics industry operates on a global scale,making the accurate translation of ingredient terminology crucial for international trade and consumer comprehension.Cosmetic ingredient terms are characterized by the...The cosmetics industry operates on a global scale,making the accurate translation of ingredient terminology crucial for international trade and consumer comprehension.Cosmetic ingredient terms are characterized by their interdisciplinary nature,regulatory constraints,and function-oriented definitions.Based on real-world translation examples,this paper analyzes the challenges in translating cosmetics ingredient terminology for international trade and proposes targeted translation strategies.The study aims to facilitate the global marketing of cosmetic products while ensuring consumers can accurately understand product ingredient information.展开更多
The axial load-bearing capacity of grouted anchorage systems is critical for rock reinforcement and reflects the interactions among system components.Hence,the mechanical response and failure characteristics of the an...The axial load-bearing capacity of grouted anchorage systems is critical for rock reinforcement and reflects the interactions among system components.Hence,the mechanical response and failure characteristics of the anchorage system under axial loading are of vital importance.They serve as the foundation for establishing the mechanical model of the anchorage system and provide significant guidance for the optimization design of bolts and the assessment of anchorage conditions.However,as the most widely used research method,current pullout tests have not paid sufficient attention to simulating actual rock mass stiffness,have not fully revealed the radial mechanical response during the pullout process,and have not clarified the locations and modes of pullout failure.To address these issues,a testing method simulating hard rock stiffness and strength was developed using elasticity and stiffness equivalence theories.Tests revealed three anchorage failure modes under equivalent hard rock stiffness:tooth cutting,sliding,and sliding-tooth cutting composite failure,with the composite failure being dominant.The pullout load-displacement curves exhibited bimodal patterns for composite failure and single peaks for tooth cutting and sliding failures.Post-peak softening showed up-convex curves for tooth cutting and down-concave curves for sliding failure,while bolt yielding displayed distinct plateaus.The radial stress trends at the rock-grout interface paralleled pullout load curves,with sliding failure exhibiting approximately 10 MPa lower peak radial stress compared to tooth cutting failure.Anchorage length most strongly affected peak load,while grout properties predominantly governed failure mode.展开更多
Objective:For patients with hypertension complicated with diabetes mellitus,their health risks are not a simple sum but present complex interactive effects.Clarifying the clinical characteristics of such patients is t...Objective:For patients with hypertension complicated with diabetes mellitus,their health risks are not a simple sum but present complex interactive effects.Clarifying the clinical characteristics of such patients is the key to solving this medical problem.Methods:From June 2023 to June 2024,this study conducted a comparative study on 100 patients with hypertension complicated with diabetes mellitus and 100 patients with hypertension alone.By retrospectively analyzing clinical data of patients,the differences in disease manifestations,complication occurrence,and treatment effects between the two groups were explored in depth,and the unique challenges and treatment difficulties faced by patients with hypertension complicated with diabetes mellitus were identified.Results:Hypertensive patients with concurrent diabetes had more difficult blood glucose and blood pressure control,and were more prone to severe complications such as cardiovascular lesions and renal damage.Conclusion:The clinical characteristics and treatment needs of patients with hypertension complicated with diabetes mellitus are different from those with hypertension alone,and disease management should be more refined and personalized.展开更多
This paper studies the structural response of high-speed train wipers under the combined action of complex flow fields and scraping actions.The stress concentration areas are determined through simulation analysis,and...This paper studies the structural response of high-speed train wipers under the combined action of complex flow fields and scraping actions.The stress concentration areas are determined through simulation analysis,and the stress and aerodynamic load measurement points are reasonably arranged accordingly.The actual measurement is carried out in combination with the operating conditions of the existing lines.The stress variations and spectral characteristics of the train under different speed levels(80,160,180,200 km/h),tunnel entry and exit,and scraper action conditions were compared and analyzed.The stress amplification factors under tunnel intersection and scraper action were obtained,providing boundary conditions for the design of wipers for highspeed s.The research results show that the maximum stress of the wiper structure obtained through simulation calculation is concentrated at the connection of the wiper arm.Structural stress increases with the rise of speed grade.The stress increases by 1.11 times when the tunnel meets.When the scraper operates,the stress on the scraper arm increases by 4.1–7.6 times.Due to the broadband excitation effect of the aerodynamic load,the spectral energy of the structure is relatively high at the natural frequency,which excites the natural mode of the wiper.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
The presence of weak interlayers in fissured rock masses significantly alters their mechanical behavior.Clarifying the dynamic response of rock matrices containing infilling materials under dynamic loading is essentia...The presence of weak interlayers in fissured rock masses significantly alters their mechanical behavior.Clarifying the dynamic response of rock matrices containing infilling materials under dynamic loading is essential for mitigating dynamic geo-hazards.Addressing the current research gap focusing predominantly on rigid or granular fillers while neglecting clayey interlayers.This investigation employs a Split Hopkinson Pressure Bar(SHPB)experimental system to systematically examine the influence of varying impact pressures and kaolinite-clay filling thicknesses on the dynamic characteristics of rock-clay combination systems.Experimental results demonstrate distinct strain-rate hardening and thickness-weakening phenomena in the dynamic compressive strength of the rock-clay combination.Energy dissipation analysis reveals that increasing lling thickness proportionally elevates reflected energy while reducing both dissipated and transmitted energy components,exhibiting a characteristic threshold behavior in energy redistribution.Failure mode transitions from localized fracturing at low energy inputs to catastrophic crushing at high impact intensities were observed.Notably,the cushioning eect of clay layers approaches saturation under high-strainrate loading conditions,where the rock matrix's intrinsic dynamic strength governs the failure mechanism.These ndings elucidate the energy absorption mechanisms of clay interlayers,oering critical insights for impact-resistant design in deep underground engineering projects.展开更多
Sichuan sausages with moisture contents of 40%,45%,50%,and 60% were stored at-18℃for durations of 0,2,4,6,and 8 weeks to evaluate the effect of moisture content on the quality attributes of Sichuan sausages during fr...Sichuan sausages with moisture contents of 40%,45%,50%,and 60% were stored at-18℃for durations of 0,2,4,6,and 8 weeks to evaluate the effect of moisture content on the quality attributes of Sichuan sausages during frozen storage.Product indicators including pH,colour,thiobarbituric acid reactive substances(TBARS),total volatile basic nitrogen(TVB-N),texture,electronic nose(E-nose)response,and water-holding capacity(thawing and cooking losses)were determined.The results indicated that as storage time increased,water retention in Sichuan sausages with different moisture contents decreased,while the degree of protein and lipid oxidation increased.This led to an increase in pH value,a colour shift from red-bright to grey-brown,and a deterioration in palatability.Among the samples,sausages with 50% moisture content exhibited the lowest thawing and cooking losses,indicating superior water-holding capacity.After 8 weeks of storage,TBARS and TVB-N values for the 50% moisture group were 19.5%and 2.5%lower,respectively,than those of the 40%and 45%moisture groups,indicating a reduced degree of oxidation.Furthermore,Sichuan sausage with 50%moisture content demonstrated an appropriate pH and colour difference,along with excellent texture and flavour,as evidenced by its higher toughness and satisfactory hardness.In conclusion,Sichuan sausage with 50% moisture content demonstrated the highest overall quality under frozen storage conditions.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
Major chemical ionic components in water serve as indicators of natural factors in the areas traversed by water bodies,and are thus widely used to elucidate key hydrogeochemical processes,including rock weathering,aqu...Major chemical ionic components in water serve as indicators of natural factors in the areas traversed by water bodies,and are thus widely used to elucidate key hydrogeochemical processes,including rock weathering,aquatic evaporation-crystallization,and the input of precipitation-derived materials into river basins.A total of 208 water samples were collected between August 2021 and August 2022 to investigate the hydrochemical characteristics and their influencing factors of the surface water and the groundwater in the Mingyong River Basin.To systematically analyze the data,we combined hydrogeochemical and statistical methods:descriptive statistics characterized ion concentration and physicochemical parameter distributions;Piper trilinear diagrams classified hydrochemical types;Pearson correlation analysis assessed ion-ion and ionTDS dependencies;Gibbs diagrams and ion ratio analysis identified solute sources;and the absolute principal component score-multiple linear regression(APCS-MLR)model quantified the contribution rates of different influencing factors.The results revealed that the dominant cations in the surface water and groundwater are Ca^(2+)and Mg^(2+),while the dominant anions are HCO_(3)^(-)and SO_(4)^(2-).The groundwater exhibits an extended residence time within rock strata,facilitating prolonged interaction with soluble minerals and intensifying the water-rock reaction process,thereby resulting in higher levels of electrical conductivity(EC),pH,and total dissolved solids(TDS)than those in the surface water.Secondly,the parameters of the surface water and groundwater indicate positive correlation.The weathering of rocks constitutes the primary solute source in the water of the basin.The hydrochemical composition of the basin water is primarily influenced by both carbonate and silicate rocks,with a minor contribution from evaporite rocks.The water bodies in the basin are affected by anthropogenic activities.The surface water is influenced by four sources,namely lixiviation-enrich,human activities,geological environmental,and unknown sources.The groundwater is influenced by five sources,namely lixiviation-enrich,primary geological,human activities,geological environmental,and unknown sources.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52374317).
文摘Understanding the bubble behaviours and flow characteristics of large-capacity bottom-blowing electric arc furnace(EAF)is crucial for potential exogenous gas-induced slag foaming process and enhancement of molten bath dynamics.A physical model and a 3D gas-slag-steel transient bottom-blowing numerical model of a 150 t EAF were established to investigate the bubble behaviour and flow characteristics throughout the molten steel bath and slag layer under bottom-blowing,with referring to gas flow rate,plug diameter,plug arrangement and injection angle.Results indicate that the average bubble sizes experience increase,dynamic stability and decrease in molten steel bath and then undergo decrease and increase after entering into slag layer for all bottom-blowing modes.The bubble numbers exhibit the opposing trends during the process.Increase in gas flow rate leads to a significant rise in average bubble size but a decrease in number,average dwelling time and the spread area of bubbles in slag layer.Increase in plug diameter causes an opposite impact.The effect of plug arrangement radii on bubbles is almost negligible.Increasing the injection angle results in an increase in bubble size and a decrease in both bubble number and dwelling time in slag layer.The slag foaming potential was discussed referring to the bubble size,number and dwelling time in slag layer.Increase in gas flow rate and plug diameters can significantly enhance the fluids flow through increasing average flow velocity,decreasing mixing time and dead zone ratio of molten bath.Plug arrangement radius and injection angle express nonlinear correlation with average flow velocity and dead zone ratio,and the plug arrangement radius of 0.5R(R represents the radius of bottom circle of EAF model)and injection angle of 15°perform better in enhancing dynamics of molten bath.A group of bottom-blowing parameters are proposed to achieve better comprehensive performance of bubble-induced slag foaming and molten bath dynamics.
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financially supported by the National Key Research and Development Program of China(No.2021YFB3701000)the National Natural Science Foundation of China(Nos.52471118,52101125,U2037601,and U21A2048)Young Elite Scientists Sponsorship Program by CAST,China(No.2022QNRC001)。
文摘The dependence of shrinkage porosities on microstructure characteristics of Mg−12Al alloy was investigated.The distribution,morphology,size,and number density of shrinkage porosities were analyzed under different cooling rates.The relationship between shrinkage porosities and microstructure characteristics was discussed in terms of temperature conditions,feeding channel characteristics,and feeding capacity.Further,the feeding behavior of the residual liquid phase in the solid skeleton was quantified by introducing permeability.Results show a strong correlation between the solid microstructure skeleton and shrinkage porosity characteristics.An increase in permeability corresponds to a declining number density of shrinkage porosities.This study aims to provide a more complete understanding how to reduce shrinkage porosities by controlling microstructure characteristics.
基金supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.T2221002)the National Natural Science Foundation of China(No.92271203)。
文摘This paper develops a method of characteristics for supersonic viscous flows.The proposed method removes the inviscid and isentropic assumptions of the classical method of characteristics.The characteristic equations and compatibility equations are derived from the governing equations for compressible viscous flow.By combining the characteristic lines,the triangular interior unit process,quadrilateral interior unit process,and direct sonic point unit process are developed.The unit processes make up the characteristic net.The numerical algorithms consider the path of flow signal propagation.The inviscid terms are solved along characteristic lines,while the viscous terms are corrected through iterative whole-field computations.The proposed method has been applied to supersonic flat-plate boundary layer and verified by the similarity solution.The errors of velocity and temperature profiles are on the order of 0.1%,while the computation efficiency is the same as the classical method of characteristics.The accuracy and efficiency make the proposed method potential to become a basic tool of analysis and design for supersonic viscous flows.
基金supported by National Natural Science Foundation of China (Nos.21906124,32302202)Natural Science Foundation of Hubei Province (No.2017CFB220)Natural Science Foundation of Shandong Province (No.ZR2023MH278)。
文摘Metal organic framework(MOF) assembled with coordination bonds has the disadvantage of poor stability that limits its application in the field of stationary phase,while covalent organic framework(COF)assembled through covalent bonds exhibits excellent structural stability.It has been shown that the stationary phases prepared by combining MOF and COF can make up for the poor stability of MOF@SiO_(2),and the MOF/COF composites have superior chromatographic separation performance.However,the traditional methods for preparing COF/MOF based stationary phases are generally solvent thermal synthesis.In this study,a green and low-cost synthesis method was proposed for the preparation of MOF/COF@SiO_(2) stationary phase.Firstly,COF@SiO_(2) was prepared in a choline chloride/ethylene glycol based deep eutectic solvent(DES).Secondly,another acid-base tunable DES prepared by mixing p-toluenesulfonic acid(PTSA)and 2-methylimidazole in different proportions was introduced as the reaction solvent and reactant for rapid synthesis of MOF/COF@SiO_(2).Compared with the toxic transition metal-based MOFs selected in most previous studies,a lightweight and non-toxic S-zone metal(calcium) based MOF was employed in this study.PTSA and calcium will form the calcium/oxygen-containing organic acid framework in acidic DES,which assembles with terephthalic acid dissolved in basic DES to form MOF.The strong hydrogen bonding effect of DES can facilitate rapid assembly of Ca-MOF.The obtained Ca-MOF/COF@SiO_(2) can be used for multi-mode chromatography to efficiently separate multiple isomeric/hydrophilic/hydrophobic analytes.The synthesis method of Ca-MOF/COF@SiO_(2) is green and mild,especially the use of acid-base tunable DES promotes the rapid synthesis of non-toxic Ca-MOF/COF@silica composites,which offers an innovative approach of greenly synthesizing novel MOF/COF stationary phases and extends their applications in the field of chromatography.
文摘The respiratory-circulatory system, including organs such as the nose, pharynx, larynx, trachea, bronchi, and heart, is an organic community responsible for ventilation and gas exchange. The integrity of its anatomical structure directly affects the evolution of pathological processes, and the analysis of their correlation is a core entry point for clinical disease diagnosis, treatment, and mechanism research. Based on this, this paper mainly explores the correlation between the anatomical and pathological characteristics of the respiratory-circulatory system, aiming to provide anatomical and pathological theoretical support for clinical accurate diagnosis, targeted therapy, and prognosis evaluation.
基金The Central Government Guides Local Foundation for Science and Technology Development(Grant No.YDZJSX2024B004).
文摘The soft actuator is characterized by high safety,flexibility,and adaptability.It is capable of both active and passive defor-mations.This paper presents a discrete degree of freedom(DOF)method for soft actuators to reveal DOF characteristics.The method draws on the superposition mechanism of the deformation characteristics of the sarcomere in the skeletal muscles of living organisms.Firstly,the multi-DOF deformation characteristics of the soft actuator are discretized into superimposed combinations of single-DOF micro-units.Then,the soft actuator was determined to contain deformation characteristics such as extension-contraction,bending,and twisting.Eighteen types of micro-units with basic deforma-tion characteristics were obtained depending on the axis and orientation.Further,the mapping relationship between the combination of micro-units and the motion characteristics of the soft actuator based on the GF set theory was established.Finally,an active-passive DOF co-structured soft actuator(APCSA)was developed.The graphical approach analyzes the experimental results,and it can be concluded that active and passive DOFs can coexist in the composite deformation of the soft actuator.
基金support from the National Natural Science Foundation of China(Grant Nos.52174313 and 52304350)thank all members of the Hebei High Quality Steel Continuous Casting Engineering Technology Research Center at North China University of Science and Technology,Tangshan,China.
文摘The flow behavior of molten steel in the thin slab mold under high casting speed conditions was investigated,with a focus on the multi-mode continuous casting and rolling mold.A steel-slag two-phase flow model was established using large eddy simulation,the volume of fluid,and magnetohydrodynamics methods through numerical simulation.The maximum flow velocity and wave height at the steel-slag interface within the mold are critical evaluation criteria for analyzing asymmetric flow under varying casting speeds and electromagnetic braking.The results indicate that the asymmetric flows within the mold do not occur synchronously.The severity of the asymmetric flow correlates with the velocity difference across the steel-slag interface.A greater biased flow prolongs the time required to revert to a steady state.When the magnetic field intensity is set to 0.24 T and the magnetic pole position is at 390 mm from the steel-slag interface,this configuration can reduce the velocity of the steel-slag interface,thereby mitigating the asymmetric flow.Additionally,it can diminish the velocity,impact depth,and impact intensity on the narrow face of the jet,thus improving the distribution of velocity and turbulent kinetic energy within the mold.This configuration prolongs the time required for the steel-slag interface to transition from a stable state to its maximum velocity and shortens the time for the interface to return to stability from an unstable state.Moreover,it ensures the positional stability of the steel-slag interface,confining its position within−3 mm.
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funded by 2025 Graduate Teaching Construction Project of USST.
文摘The cosmetics industry operates on a global scale,making the accurate translation of ingredient terminology crucial for international trade and consumer comprehension.Cosmetic ingredient terms are characterized by their interdisciplinary nature,regulatory constraints,and function-oriented definitions.Based on real-world translation examples,this paper analyzes the challenges in translating cosmetics ingredient terminology for international trade and proposes targeted translation strategies.The study aims to facilitate the global marketing of cosmetic products while ensuring consumers can accurately understand product ingredient information.
基金supported by the National Natural Science Foundation of China(Grant No.52279116)the Key Projects of the Yalong River Joint Fund of the National Natural Science Foundation of China(Grant No.U1865203).
文摘The axial load-bearing capacity of grouted anchorage systems is critical for rock reinforcement and reflects the interactions among system components.Hence,the mechanical response and failure characteristics of the anchorage system under axial loading are of vital importance.They serve as the foundation for establishing the mechanical model of the anchorage system and provide significant guidance for the optimization design of bolts and the assessment of anchorage conditions.However,as the most widely used research method,current pullout tests have not paid sufficient attention to simulating actual rock mass stiffness,have not fully revealed the radial mechanical response during the pullout process,and have not clarified the locations and modes of pullout failure.To address these issues,a testing method simulating hard rock stiffness and strength was developed using elasticity and stiffness equivalence theories.Tests revealed three anchorage failure modes under equivalent hard rock stiffness:tooth cutting,sliding,and sliding-tooth cutting composite failure,with the composite failure being dominant.The pullout load-displacement curves exhibited bimodal patterns for composite failure and single peaks for tooth cutting and sliding failures.Post-peak softening showed up-convex curves for tooth cutting and down-concave curves for sliding failure,while bolt yielding displayed distinct plateaus.The radial stress trends at the rock-grout interface paralleled pullout load curves,with sliding failure exhibiting approximately 10 MPa lower peak radial stress compared to tooth cutting failure.Anchorage length most strongly affected peak load,while grout properties predominantly governed failure mode.
文摘Objective:For patients with hypertension complicated with diabetes mellitus,their health risks are not a simple sum but present complex interactive effects.Clarifying the clinical characteristics of such patients is the key to solving this medical problem.Methods:From June 2023 to June 2024,this study conducted a comparative study on 100 patients with hypertension complicated with diabetes mellitus and 100 patients with hypertension alone.By retrospectively analyzing clinical data of patients,the differences in disease manifestations,complication occurrence,and treatment effects between the two groups were explored in depth,and the unique challenges and treatment difficulties faced by patients with hypertension complicated with diabetes mellitus were identified.Results:Hypertensive patients with concurrent diabetes had more difficult blood glucose and blood pressure control,and were more prone to severe complications such as cardiovascular lesions and renal damage.Conclusion:The clinical characteristics and treatment needs of patients with hypertension complicated with diabetes mellitus are different from those with hypertension alone,and disease management should be more refined and personalized.
文摘This paper studies the structural response of high-speed train wipers under the combined action of complex flow fields and scraping actions.The stress concentration areas are determined through simulation analysis,and the stress and aerodynamic load measurement points are reasonably arranged accordingly.The actual measurement is carried out in combination with the operating conditions of the existing lines.The stress variations and spectral characteristics of the train under different speed levels(80,160,180,200 km/h),tunnel entry and exit,and scraper action conditions were compared and analyzed.The stress amplification factors under tunnel intersection and scraper action were obtained,providing boundary conditions for the design of wipers for highspeed s.The research results show that the maximum stress of the wiper structure obtained through simulation calculation is concentrated at the connection of the wiper arm.Structural stress increases with the rise of speed grade.The stress increases by 1.11 times when the tunnel meets.When the scraper operates,the stress on the scraper arm increases by 4.1–7.6 times.Due to the broadband excitation effect of the aerodynamic load,the spectral energy of the structure is relatively high at the natural frequency,which excites the natural mode of the wiper.
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supported by the Natural Science Foundation of China(No.52204083)2022 independent project of State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines(Grant No.SKLMRDPC22KF01).
文摘The presence of weak interlayers in fissured rock masses significantly alters their mechanical behavior.Clarifying the dynamic response of rock matrices containing infilling materials under dynamic loading is essential for mitigating dynamic geo-hazards.Addressing the current research gap focusing predominantly on rigid or granular fillers while neglecting clayey interlayers.This investigation employs a Split Hopkinson Pressure Bar(SHPB)experimental system to systematically examine the influence of varying impact pressures and kaolinite-clay filling thicknesses on the dynamic characteristics of rock-clay combination systems.Experimental results demonstrate distinct strain-rate hardening and thickness-weakening phenomena in the dynamic compressive strength of the rock-clay combination.Energy dissipation analysis reveals that increasing lling thickness proportionally elevates reflected energy while reducing both dissipated and transmitted energy components,exhibiting a characteristic threshold behavior in energy redistribution.Failure mode transitions from localized fracturing at low energy inputs to catastrophic crushing at high impact intensities were observed.Notably,the cushioning eect of clay layers approaches saturation under high-strainrate loading conditions,where the rock matrix's intrinsic dynamic strength governs the failure mechanism.These ndings elucidate the energy absorption mechanisms of clay interlayers,oering critical insights for impact-resistant design in deep underground engineering projects.
基金Supported by National Modern Agricultural Industry Technology System Sichuan Pig Innovation Team(SCCXTD-2026-8)Sichuan Science and Technology Program(2025ZYD0049)"Challenge and Leadership"Project for Key Core Technologies of Sui Ning in Sichuan(2025SNKBZ19).
文摘Sichuan sausages with moisture contents of 40%,45%,50%,and 60% were stored at-18℃for durations of 0,2,4,6,and 8 weeks to evaluate the effect of moisture content on the quality attributes of Sichuan sausages during frozen storage.Product indicators including pH,colour,thiobarbituric acid reactive substances(TBARS),total volatile basic nitrogen(TVB-N),texture,electronic nose(E-nose)response,and water-holding capacity(thawing and cooking losses)were determined.The results indicated that as storage time increased,water retention in Sichuan sausages with different moisture contents decreased,while the degree of protein and lipid oxidation increased.This led to an increase in pH value,a colour shift from red-bright to grey-brown,and a deterioration in palatability.Among the samples,sausages with 50% moisture content exhibited the lowest thawing and cooking losses,indicating superior water-holding capacity.After 8 weeks of storage,TBARS and TVB-N values for the 50% moisture group were 19.5%and 2.5%lower,respectively,than those of the 40%and 45%moisture groups,indicating a reduced degree of oxidation.Furthermore,Sichuan sausage with 50%moisture content demonstrated an appropriate pH and colour difference,along with excellent texture and flavour,as evidenced by its higher toughness and satisfactory hardness.In conclusion,Sichuan sausage with 50% moisture content demonstrated the highest overall quality under frozen storage conditions.
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funded by the National Natural Science Foundation of China(No.42061012)the Open Project of Yunnan Province’s First Class Discipline of Soil and Water Conservation and Desertification Control(SBK20240019)。
文摘Major chemical ionic components in water serve as indicators of natural factors in the areas traversed by water bodies,and are thus widely used to elucidate key hydrogeochemical processes,including rock weathering,aquatic evaporation-crystallization,and the input of precipitation-derived materials into river basins.A total of 208 water samples were collected between August 2021 and August 2022 to investigate the hydrochemical characteristics and their influencing factors of the surface water and the groundwater in the Mingyong River Basin.To systematically analyze the data,we combined hydrogeochemical and statistical methods:descriptive statistics characterized ion concentration and physicochemical parameter distributions;Piper trilinear diagrams classified hydrochemical types;Pearson correlation analysis assessed ion-ion and ionTDS dependencies;Gibbs diagrams and ion ratio analysis identified solute sources;and the absolute principal component score-multiple linear regression(APCS-MLR)model quantified the contribution rates of different influencing factors.The results revealed that the dominant cations in the surface water and groundwater are Ca^(2+)and Mg^(2+),while the dominant anions are HCO_(3)^(-)and SO_(4)^(2-).The groundwater exhibits an extended residence time within rock strata,facilitating prolonged interaction with soluble minerals and intensifying the water-rock reaction process,thereby resulting in higher levels of electrical conductivity(EC),pH,and total dissolved solids(TDS)than those in the surface water.Secondly,the parameters of the surface water and groundwater indicate positive correlation.The weathering of rocks constitutes the primary solute source in the water of the basin.The hydrochemical composition of the basin water is primarily influenced by both carbonate and silicate rocks,with a minor contribution from evaporite rocks.The water bodies in the basin are affected by anthropogenic activities.The surface water is influenced by four sources,namely lixiviation-enrich,human activities,geological environmental,and unknown sources.The groundwater is influenced by five sources,namely lixiviation-enrich,primary geological,human activities,geological environmental,and unknown sources.
