An experimental study on co-pyrolysis of bituminous coal and biomass was performed in a pressured fluidized bed reactor.The blend ratio of biomass in the mixture was varied between 0 and 100 wt%,and the temperature wa...An experimental study on co-pyrolysis of bituminous coal and biomass was performed in a pressured fluidized bed reactor.The blend ratio of biomass in the mixture was varied between 0 and 100 wt%,and the temperature was over a range of 550–650℃ under 1.0 MPa pressure with different atmospheres.On the basis of the individual pyrolysis behavior of bituminous coal and biomass,the influences of the biomass blending ratio,temperature,pressure and atmosphere on the product distribution were investigated.The results indicated that there existed a synergetic effect in the co-pyrolysis of bituminous coal and biomass in this pressured fluidized bed reactor,especially when the condition of bituminous coal and biomass blend ratio of 70:30(w/w),600℃,and 0.3 MPa was applied.The addition of biomass influenced the tar and char yields and gas and tar composition during co-pyrolysis.The tar yields were higher than the calculated values from individual pyrolysis of each fuel,and consequently the char yields were lower.The experimental results showed that the composition of the gaseous products was not in accordance with those of their individual fuel.The improvement of composition in tar also indicated synergistic effect in the co-pyrolysis.展开更多
A pressured microwave-assisted hydrolysis （PMAH） technique has been developed for hydrolyzing the crude glycyrrhizic acid （GA） extracted from licorice root to prepare glycyrrhetinic acid （GRA）. In order to optim...A pressured microwave-assisted hydrolysis （PMAH） technique has been developed for hydrolyzing the crude glycyrrhizic acid （GA） extracted from licorice root to prepare glycyrrhetinic acid （GRA）. In order to optimize the efficiency of PMAH, several experimental parameters were investigated, including liquid-solid ratio, hydrolysis time, sulfuric acid concentration and hydrolysis temperature. The optimized hydrolysis conditions were as follows：pressured microwave-assisted hydrolysis of crude GA for 21 min （taking 15 min to reach 150 ℃, and holding it for 6 rain） at 150 ℃ （at a radiation power of 450 W） in 3%-5% sulfuric acid solution with the liquid-solid （ml.g-1 crude GA） ratio of 25 ： 1. As a result of the considerable saving in time and higher product yields （up to 90%）, PMAH was proved more effective than conventional methods.展开更多
Biogas is a kind of regenerable energy which is inexpensive and friendly to the environment, but the potential ofbiogas is difficult to develop fully in China, for most biogas have badly qualities and the utilization ...Biogas is a kind of regenerable energy which is inexpensive and friendly to the environment, but the potential ofbiogas is difficult to develop fully in China, for most biogas have badly qualities and the utilization of it is monotonous. The suitable operation term about biogas upgrading by pressurized water scrubbing was researched through the orthogonal test in this study. Two sorts of scrubber packing included the random multidimensional hollow sphere packing and the structured screen packing were also used, and the effects of experiment factors included packing, water temperature, gas flow speed, water flow speed and washing pressure were studied. The results showed that better effect was got when the screen structured packing was used; all the five test factors affected the processing significantly in the arrange as before and had better and better significant effects.展开更多
Application of pressured grouting method (PGM) in pile engineering can tackle problems encountered during construction of bored piles. Bearing capacity of piles can be increased through compaction of subsoils around p...Application of pressured grouting method (PGM) in pile engineering can tackle problems encountered during construction of bored piles. Bearing capacity of piles can be increased through compaction of subsoils around piles. This paper reports research efforts of this technique by the pile research team in Southwest Jiaotong University in last decade with respect to the construction process, test findings, and primary research conclusions. The social-economical benefits of this method and application market in pile engineering are also analyzed.展开更多
Lithium–sulfur(Li–S)batteries are promisingcandidates for next-generation energy storagegiven their high energy density and potential low cost.Chemically activated carbon(CAC)is often used fortheir cathodes,because ...Lithium–sulfur(Li–S)batteries are promisingcandidates for next-generation energy storagegiven their high energy density and potential low cost.Chemically activated carbon(CAC)is often used fortheir cathodes,because it has a high specific surfacearea for sulfur loading.We have developed a pressurizedphysical activation(PPA)method that producedan activated carbon(PPAC)with a high specific surfacearea comparable to that of CAC.The pore structure of PPAC could be changed and its use as a cathode material for Li–Sbatteries was investigated.Battery tests at different capacity rates(C-rates)showed that it had a much improved high-rate performancewith a discharge capacity of 900 mAh/(g of sulfur)at 1 C,in contrast to only 600 mAh/(g of sulfur)for CAC.Porestructure analyses showed that PPAC prepared at a high activation temperature(1000℃)had unusual channel-like mesoporesbetween the microdomains that are the basic structural units of artificial carbon materials.These are connected to microporesdeveloped in each microdomain,and deliver ions from the surroundings to the internal pores and vice versa.The well-developedmicropores and mesopores of PPAC respectively ensured the high adsorption of lithium polysulfides and a high rate ofion diffusion.Compared to CAC,PPAC is a high-performance,low-cost cathode material that is promising for use in futureLi–S batteries.展开更多
平均动脉压(mean arterial pressure,MAP)和脉压是反映脑灌注的两项指标,其在急性缺血性脑卒中后能否指导降压治疗策略的选择尚不明确。本研究基于中国急性缺血性脑卒中降压试验(the China antihypertensive trial in acute ischemic st...平均动脉压(mean arterial pressure,MAP)和脉压是反映脑灌注的两项指标,其在急性缺血性脑卒中后能否指导降压治疗策略的选择尚不明确。本研究基于中国急性缺血性脑卒中降压试验(the China antihypertensive trial in acute ischemic stroke,CATIS),根据MAP和脉压水平进行分层,探讨早期降压干预对缺血性脑卒中后不良临床结局的影响。方法:该试验将4 071例收缩压升高的急性缺血性脑卒中患者随机分配至降压治疗组(目标是在随机化后24h内收缩压降低10%~25%,7 d内血压将至<140/90 mm Hg,并在住院期间维持该水平,1 mm Hg=0.133 k Pa)或住院期间停止降压治疗的对照组。展开更多
Large-volume presses(LVPs)are widely utilized in diverse research fields—including high-pressure physics,chemistry,materials science,and Earth and planetary sciences—to investigate the physical and chemical properti...Large-volume presses(LVPs)are widely utilized in diverse research fields—including high-pressure physics,chemistry,materials science,and Earth and planetary sciences—to investigate the physical and chemical properties of materials under extreme high-pressure and hightemperature conditions.A prerequisite for achieving reproducible property measurements is the determination and control of pressure within experimental setups.However,the lack of precise pressure calibration in LVPs hinders the broader application of such devices in ultrahigh-pressure studies.This study employs a suite of standard phase transition-based pressure markers—comprising metallic conductors,semiconductors,and minerals—through both in situ and ex situ identification approaches,to establish pressure calibration curves ranging from 0.4 to>30 GPa for various types of LVP installed at the Center for High Pressure Science and Technology Advanced Research(HPSTAR),Beijing,including piston–cylinder,cubic,and multi-anvil presses.The results provide a unified and traceable pressure reference for highpressure experiments conducted at HPSTAR,while also offering technical guidance and calibration standards for other researchers utilizing similar LVP systems,thereby enabling more consistent comparison between different laboratories.This work facilitates the advancement of LVP research toward broader applications in higher-pressure regimes.展开更多
The intrinsic pressure framework,which treats self-propelling force as an external force,provides a convenient and consistent description of mechanical equilibrium in active matter.However,direct experimental evidence...The intrinsic pressure framework,which treats self-propelling force as an external force,provides a convenient and consistent description of mechanical equilibrium in active matter.However,direct experimental evidence is still lacking.To validate this framework,here we employ a programmable robotic platform,where a single light-controlled wheeled robot travels in an activity landscape.Our experiments quantitatively demonstrate that the intrinsic pressure difference across the activity interface is balanced by the emerged polarization force.This result unambiguously confirms the theoretical predictions,thus validating the intrinsic pressure framework and laying the experimental foundation for the intrinsic pressure-based mechanical description of dry active matter.展开更多
The capillary pressure curve provides fundamental insights into the dynamics of fluid-fluid displacement and phase distributions.Capillary scaling is crucial for extrapolating capillary pressure-saturation data from l...The capillary pressure curve provides fundamental insights into the dynamics of fluid-fluid displacement and phase distributions.Capillary scaling is crucial for extrapolating capillary pressure-saturation data from laboratory tests to field applications.However,the classic scaling method fails to capture the effect of wettability as the pore surface approaches neutral wetting.Here,inspired by the role of pore-filling events in controlling fluid-fluid displacement,we perform a theoretical analysis of the burst events occurring during drainage processes.We find that the median threshold capillary pressure,which corresponds to the occurrence of burst events for the median pore throat,is closely correlated with the capillary pressure curve across various contact angles.Using this concept,we propose a new scaling method for capillary pressure curves under various wetting conditions.We conduct microfluidic experiments and pore-network modeling across different contact angles,porosities,and disorders to evaluate the new scaling methods,indicating that the new scaling method performs better than the Leverett J-function as the contact angle approaches 90°.We further perform geometry analysis on the critical radius of curvature for burst events in an ideal tetrahedral arrangement and extend the new scaling method to 3D(three-dimensional)porous media.Model evaluation shows that the 3D version of the scaling method also performs well but requires fewer parameters compared to the Leverett J-function.Our work enhances the prediction and interpretation of experimental data for capillary pressure curves under various wet conditions,and more importantly,establishes a methodology that relates Darcy-scale flow behavior to pore-scale fluid displacements.展开更多
BACKGROUND:Individualized positive end-expiratory pressure(PEEP)titration is a crucial technique in mechanical ventilation therapy for acute respiratory distress syndrome(ARDS)patients with intra-abdominal hypertensio...BACKGROUND:Individualized positive end-expiratory pressure(PEEP)titration is a crucial technique in mechanical ventilation therapy for acute respiratory distress syndrome(ARDS)patients with intra-abdominal hypertension(IAH).This study aimed to evaluate the eff ectiveness of electrical impedance tomography(EIT)-guided PEEP titration in this population.METHODS:This prospective study enrolled 36 ARDS patients,including 22 patients with IAH and 14 without IAH.All the patients underwent EIT-guided PEEP titration at the intersection point between alveolar overdistension and collapse during a decremental PEEP trial.The changes in pulmonary ventilation distribution,respiratory mechanics and hemodynamics during the titration process were observed.RESULTS:After EIT-guided PEEP titration was performed,the PEEP,peak inspiratory pressure and plateau pressure increased significantly(P<0.05).Furthermore,no significant differences were observed in respiratory system compliance,tidal volume,driving pressure,or the 4*DP+RR index between the two groups(P>0.05).The mechanical power increased in the non-IAH(NIAH)group after PEEP titration(P<0.05).Ventilation in gravity-dependent lung regions significantly increased(P<0.05),and the oxygenation index(PaO2/FiO2)improved signifi cantly(P<0.05)in both groups.However,blood pressure,heart rate,respiratory rate,central venous pressure,and lactate levels did not signifi cantly change.In the IAH group,the PaO2/FiO2 ratio improved less than that in the NIAH group did(P<0.05).CONCLUSION:In our study,individualized PEEP titration guided by EIT improved oxygenation in ARDS patients with concomitant IAH without signifi cantly aff ecting hemodynamics.The presence of IAH may limit the improvement of oxygenation during EIT-guided PEEP titration.展开更多
Wearable sensors integrated with deep learning techniques have the potential to revolutionize seamless human-machine interfaces for real-time health monitoring,clinical diagnosis,and robotic applications.Nevertheless,...Wearable sensors integrated with deep learning techniques have the potential to revolutionize seamless human-machine interfaces for real-time health monitoring,clinical diagnosis,and robotic applications.Nevertheless,it remains a critical challenge to simultaneously achieve desirable mechanical and electrical performance along with biocompatibility,adhesion,self-healing,and environmental robustness with excellent sensing metrics.Herein,we report a multifunctional,anti-freezing,selfadhesive,and self-healable organogel pressure sensor composed of cobalt nanoparticle encapsulated nitrogen-doped carbon nanotubes(CoN CNT)embedded in a polyvinyl alcohol-gelatin(PVA/GLE)matrix.Fabricated using a binary solvent system of water and ethylene glycol(EG),the CoN CNT/PVA/GLE organogel exhibits excellent flexibility,biocompatibility,and temperature tolerance with remarkable environmental stability.Electrochemical impedance spectroscopy confirms near-stable performance across a broad humidity range(40%-95%RH).Freeze-tolerant conductivity under sub-zero conditions(-20℃)is attributed to the synergistic role of CoN CNT and EG,preserving mobility and network integrity.The Co N CNT/PVA/GLE organogel sensor exhibits high sensitivity of 5.75 k Pa^(-1)in the detection range from 0 to 20 k Pa,ideal for subtle biomechanical motion detection.A smart human-machine interface for English letter recognition using deep learning achieved 98%accuracy.The organogel sensor utility was extended to detect human gestures like finger bending,wrist motion,and throat vibration during speech.展开更多
While a healthy lifestyle is known to reduce the risk of stroke,the extent to which blood pressure(BP)mediates this association remains unclear.The present study aimed to quantify the mediating role of BP in the assoc...While a healthy lifestyle is known to reduce the risk of stroke,the extent to which blood pressure(BP)mediates this association remains unclear.The present study aimed to quantify the mediating role of BP in the association between combined lifestyle factors and stroke incidence.Using data from 51929 participants free of major cardiovascular diseases or cancer at baseline,we employed structural equation modeling to assess the mediating effects of systolic(SBP)and diastolic(DBP)blood pressure.During the follow-up,2811 incident stroke cases were identified.A healthy lifestyle was significantly associated with a reduced risk of stroke,with SBP mediating 44.70%(β=-0.0014,95%confidence interval[CI]:-0.0016 to-0.0012)and DBP mediating 37.81%(β=-0.0012,95%CI:-0.0015 to-0.0009)of this association.The mediating effects were attenuated but remained significant for ischemic stroke(SBP:33.21%;DBP:27.24%).In conclusion,approximately two-fifths of the protective association between a healthy lifestyle and stroke may be mediated by BP.These findings suggest that BP control may serve as an important early indicator for evaluating the effectiveness of lifestyle interventions in reducing stroke risk.展开更多
Material phase-transition represents a significant phenomenon and mechanism in the context of hypervelocity protection.This study presents a thorough analysis of the phase-transition phenomena induced by shock pressur...Material phase-transition represents a significant phenomenon and mechanism in the context of hypervelocity protection.This study presents a thorough analysis of the phase-transition phenomena induced by shock pressure as the shock wave propagates initially to the rear of the projectile.The shock wave that induces a phase-transition is commonly referred to as a macroscopic phase-transition wave,whereas the interface that separates the distinct phases is referred to as macroscopic phase-boundary.The contact interface between the spherical projectile and the thin plate,characterized by its curved surface,plays a significant role in the nonlinear propagation and evolution of wave systems.The pressure distribution along the central axis of a spherical projectile is derived in accordance with the linear decay law observed for axial pressure.On this basis,a quadratic function is employed to characterize the trend of changes in wave front pressure,thereby facilitating the establishment of a model for wave front pressure distribution.Using the phase-transition pressure criterion for materials,the wave front phase evolution process is derived,and the macroscopic phase-boundary is determined.Based on the geometric propagation model(GPM)and the pressure distribution of the wave front,a phase geometric propagation model(PGPM)is proposed.The phase distribution of a spherical projectile impacting a thin plate is obtained by theoretical methods.The accuracy of the PGPM is subsequently validated through a comparison of its results with those obtained from numerical simulations.展开更多
This study presents a numerical investigation of the transient relaxation dynamics of a near-critical CO_(2)droplet immersed in a warmer supercritical environment composed of the same fluid.Three thermodynamic regimes...This study presents a numerical investigation of the transient relaxation dynamics of a near-critical CO_(2)droplet immersed in a warmer supercritical environment composed of the same fluid.Three thermodynamic regimes were analysed:quasi-critical(T_(r)=1.01,P_(r)=1.01),transitional(T_(r)=2.01,P_(r)=1.01),and deep supercritical(T_(r)=5.01,P_(r)=3.01).Theevolution of density,temperature,and velocity fieldswas examined to characterize the internal structure and stability of the interfacial transition layer.The evolution of density,temperature,and velocity fields highlights the competition between thermal diffusion,compressibility,andmass confinement in shaping the stability of the interfacial transition layer.Near the critical point,strong gradients and flux discontinuities emerge,consistent with known instabilities,whereas higher reduced conditions promote homogenization and stabilized transport.In the deep supercritical regime,smooth and nearly uniform fields indicate robust thermal stability.The model is validated against prior studies on droplet evaporation under supercritical and trans-critical conditions.Beyond theoretical insights,the results underline practical implications for advanced propulsion,heat transfer,and evaporation systems as well as for safe CO_(2)supercritical storage and extraction processes in energy,aerospace,pharmaceutical,and materials industries.展开更多
Improving device efficiency is fundamental for advancing energy harvesting technology,particularly in systems designed to convert light energy into electrical output.In our previous studies,we developed a basic struct...Improving device efficiency is fundamental for advancing energy harvesting technology,particularly in systems designed to convert light energy into electrical output.In our previous studies,we developed a basic structure light pressure electric generator(Basic-LPEG),which utilized a layered configuration of Ag/Pb(Zr,Ti)O_(3)(PZT)/Pt/GaAs to generate electricity based on light-induced pressure on the PZT.In this study,we sought to enhance the performance of this Basic-LPEG by introducing Ag nanoparticles/graphene oxide(AgNPs/GO)composite units(NP-LPEG),creating upgraded harvesting device.Specifically,by depositing the AgNPs/GO units twice onto the Basic-LPEG,we observed an increase in output voltage and current from 241 mV and 3.1μA to 310 mV and 9.3μA,respectively,under a solar simulator.The increase in electrical output directly correlated with the intensity of the light pressure impacting the PZT,as well as matched the Raman measurements,finite-difference time-domain simulations,and COMSOL Multiphysics Simulation.Experimental data revealed that the enhancement in electrical output was proportional to the number of hot spots generated between Ag nanoparticles,where the electric field experienced substantial amplification.These results underline the effectiveness of AgNPs/GO units in boosting the light-induced electric generation capacity,thereby providing a promising pathway for high-efficiency energy harvesting devices.展开更多
Drilling and blasting tunneling is a cyclic process in which tunnel rock undergoes repeated blast loading,affecting its dynamic characteristics,energy evolution,and damage progression.To explore the dynamic mechanical...Drilling and blasting tunneling is a cyclic process in which tunnel rock undergoes repeated blast loading,affecting its dynamic characteristics,energy evolution,and damage progression.To explore the dynamic mechanical properties and damage mechanisms of carbonaceous slate under cyclic impact loads of varying intensities,cyclic dynamic tests are conducted using a triaxial split Hopkinson pressure bar.This study analyzes the stress-strain relationship,energy damage evolution,and macro-to-micro failure characteristics.The results show that peak stress and strain are significantly influenced by impact intensity and the number of impacts.The initial dynamic stress is positively correlated with the impact intensity,but with more impact,the dynamic stress decreases while the peak strain increases.Energy evolution follows a pattern of"slow growthfluctuating growthrapid growth,"with the crack initiation stress and its proportion decreasing.CT and SEM analyses reveal that as the impact intensity increases,failure becomes more chaotic,the fracture volume increases,and the fracture mode shifts from interlayer and intergranular to through-layer and trans-granular fractures.These findings provide an experimental basis for soft rock tunnel stability analysis.展开更多
Accurate blood pressure(BP)monitoring is essential for preventing and managing cardiovascular disease.Advancements in materials science,medicine,flexible electronic,and artificial intelligence(AI)have enabled cuffless...Accurate blood pressure(BP)monitoring is essential for preventing and managing cardiovascular disease.Advancements in materials science,medicine,flexible electronic,and artificial intelligence(AI)have enabled cuffless,unobtrusive BP monitoring systems,offering an alternative to traditional sphygmomanometers.However,extending these advances to real-world cardiovascular care particularly in resource-limited settings remains challenging due to constraints in computational resources,power efficiency,and deployment scalability.This review presents a comprehensive synthesis of AI-enhanced wearable BP monitoring,emphasizing its potential for personalized,scalable,and accessible healthcare.We systematically analyze the end-to-end system architecture,from mechano-electric sensing principles and AI-based estimation models to edge-aware deployment strategies tailored for low-resource environments.We further discuss clinical validation metrics and implementation barriers and prospective strategies.To bridge lab-to-field translation,we propose an innovative"sensor-model-deployment-assessment"co-design framework.This roadmap highlights how AI-enhanced BP technologies can support proactive hypertension control and promote cardiovascular health equity on a global scale.展开更多
Flexible pressure sensors(FPSs)offer unique benefits for fall detection and rehabilitation training,but conventional FPSs made from synthetic materials have drawbacks,including resource-heavy manufacturing,high costs,...Flexible pressure sensors(FPSs)offer unique benefits for fall detection and rehabilitation training,but conventional FPSs made from synthetic materials have drawbacks,including resource-heavy manufacturing,high costs,and environmental pollution.To address these limitations,this study proposes an innovative fabrication strategy for FPS based on natural materials.The upper and lower electrodes were made by treating a natural wood strip with a flame retardant,converting it into high-quality graphene via a costeffective infrared laser,and transferring it onto starch-based substrates.The dielectric layer was created by electrospinning a composite nanofiber membrane with cyclodextrin and carbon nanotubes.The resulting capacitive FPS shows high sensitivity(2.15 kPa^(-1) within 0-10 kPa),a low detection limit(~6.5 Pa),fast response and recovery times(29 and 39 ms),and excellent long-term stability(over 5000 cycles).It also demonstrates excellent biocompatibility(cell viability>98%)and fully degrades within 6 h.By integrating this sensor with wireless technology,a fall detection and rehabilitation monitoring system was developed.Data processing was handled by a Tiny Machine Learning module on a mobile platform,which transmitted relevant data to a cloud-based platform.The system accurately identified five common fall postures and assisted clinicians in guiding rehabilitation exercises,achieving recognition accuracies of 99%and 100%,respectively,offering a sustainable healthcare solution for the elderly.展开更多
基金Supported by Hydrocarbon High-efficiency Utilization Technology Research Center of Yanchang Petroleum(Group)Co.Ltd.,China(ycsy2013ky-A-30)
文摘An experimental study on co-pyrolysis of bituminous coal and biomass was performed in a pressured fluidized bed reactor.The blend ratio of biomass in the mixture was varied between 0 and 100 wt%,and the temperature was over a range of 550–650℃ under 1.0 MPa pressure with different atmospheres.On the basis of the individual pyrolysis behavior of bituminous coal and biomass,the influences of the biomass blending ratio,temperature,pressure and atmosphere on the product distribution were investigated.The results indicated that there existed a synergetic effect in the co-pyrolysis of bituminous coal and biomass in this pressured fluidized bed reactor,especially when the condition of bituminous coal and biomass blend ratio of 70:30(w/w),600℃,and 0.3 MPa was applied.The addition of biomass influenced the tar and char yields and gas and tar composition during co-pyrolysis.The tar yields were higher than the calculated values from individual pyrolysis of each fuel,and consequently the char yields were lower.The experimental results showed that the composition of the gaseous products was not in accordance with those of their individual fuel.The improvement of composition in tar also indicated synergistic effect in the co-pyrolysis.
基金Supported by the Yunnan Provincial Department of Education Key Foundation (07Z10311)
文摘A pressured microwave-assisted hydrolysis （PMAH） technique has been developed for hydrolyzing the crude glycyrrhizic acid （GA） extracted from licorice root to prepare glycyrrhetinic acid （GRA）. In order to optimize the efficiency of PMAH, several experimental parameters were investigated, including liquid-solid ratio, hydrolysis time, sulfuric acid concentration and hydrolysis temperature. The optimized hydrolysis conditions were as follows：pressured microwave-assisted hydrolysis of crude GA for 21 min （taking 15 min to reach 150 ℃, and holding it for 6 rain） at 150 ℃ （at a radiation power of 450 W） in 3%-5% sulfuric acid solution with the liquid-solid （ml.g-1 crude GA） ratio of 25 ： 1. As a result of the considerable saving in time and higher product yields （up to 90%）, PMAH was proved more effective than conventional methods.
基金Supported by National Science and Technology Supporting Plan (2008BADC4B02)
文摘Biogas is a kind of regenerable energy which is inexpensive and friendly to the environment, but the potential ofbiogas is difficult to develop fully in China, for most biogas have badly qualities and the utilization of it is monotonous. The suitable operation term about biogas upgrading by pressurized water scrubbing was researched through the orthogonal test in this study. Two sorts of scrubber packing included the random multidimensional hollow sphere packing and the structured screen packing were also used, and the effects of experiment factors included packing, water temperature, gas flow speed, water flow speed and washing pressure were studied. The results showed that better effect was got when the screen structured packing was used; all the five test factors affected the processing significantly in the arrange as before and had better and better significant effects.
文摘Application of pressured grouting method (PGM) in pile engineering can tackle problems encountered during construction of bored piles. Bearing capacity of piles can be increased through compaction of subsoils around piles. This paper reports research efforts of this technique by the pile research team in Southwest Jiaotong University in last decade with respect to the construction process, test findings, and primary research conclusions. The social-economical benefits of this method and application market in pile engineering are also analyzed.
文摘Lithium–sulfur(Li–S)batteries are promisingcandidates for next-generation energy storagegiven their high energy density and potential low cost.Chemically activated carbon(CAC)is often used fortheir cathodes,because it has a high specific surfacearea for sulfur loading.We have developed a pressurizedphysical activation(PPA)method that producedan activated carbon(PPAC)with a high specific surfacearea comparable to that of CAC.The pore structure of PPAC could be changed and its use as a cathode material for Li–Sbatteries was investigated.Battery tests at different capacity rates(C-rates)showed that it had a much improved high-rate performancewith a discharge capacity of 900 mAh/(g of sulfur)at 1 C,in contrast to only 600 mAh/(g of sulfur)for CAC.Porestructure analyses showed that PPAC prepared at a high activation temperature(1000℃)had unusual channel-like mesoporesbetween the microdomains that are the basic structural units of artificial carbon materials.These are connected to microporesdeveloped in each microdomain,and deliver ions from the surroundings to the internal pores and vice versa.The well-developedmicropores and mesopores of PPAC respectively ensured the high adsorption of lithium polysulfides and a high rate ofion diffusion.Compared to CAC,PPAC is a high-performance,low-cost cathode material that is promising for use in futureLi–S batteries.
文摘平均动脉压(mean arterial pressure,MAP)和脉压是反映脑灌注的两项指标,其在急性缺血性脑卒中后能否指导降压治疗策略的选择尚不明确。本研究基于中国急性缺血性脑卒中降压试验(the China antihypertensive trial in acute ischemic stroke,CATIS),根据MAP和脉压水平进行分层,探讨早期降压干预对缺血性脑卒中后不良临床结局的影响。方法:该试验将4 071例收缩压升高的急性缺血性脑卒中患者随机分配至降压治疗组(目标是在随机化后24h内收缩压降低10%~25%,7 d内血压将至<140/90 mm Hg,并在住院期间维持该水平,1 mm Hg=0.133 k Pa)或住院期间停止降压治疗的对照组。
基金supported by the National Science Foundation of China(Grant Nos.U1530402 and U1930401).
文摘Large-volume presses(LVPs)are widely utilized in diverse research fields—including high-pressure physics,chemistry,materials science,and Earth and planetary sciences—to investigate the physical and chemical properties of materials under extreme high-pressure and hightemperature conditions.A prerequisite for achieving reproducible property measurements is the determination and control of pressure within experimental setups.However,the lack of precise pressure calibration in LVPs hinders the broader application of such devices in ultrahigh-pressure studies.This study employs a suite of standard phase transition-based pressure markers—comprising metallic conductors,semiconductors,and minerals—through both in situ and ex situ identification approaches,to establish pressure calibration curves ranging from 0.4 to>30 GPa for various types of LVP installed at the Center for High Pressure Science and Technology Advanced Research(HPSTAR),Beijing,including piston–cylinder,cubic,and multi-anvil presses.The results provide a unified and traceable pressure reference for highpressure experiments conducted at HPSTAR,while also offering technical guidance and calibration standards for other researchers utilizing similar LVP systems,thereby enabling more consistent comparison between different laboratories.This work facilitates the advancement of LVP research toward broader applications in higher-pressure regimes.
基金supported by the National Natural Science Foundation of China (Grant Nos.T2325027,12274448,T2350007,12404239,12174041,12325405,12090054,and T2221001)the National Key R&D Program of China (Grant No.2022YFF0503504)。
文摘The intrinsic pressure framework,which treats self-propelling force as an external force,provides a convenient and consistent description of mechanical equilibrium in active matter.However,direct experimental evidence is still lacking.To validate this framework,here we employ a programmable robotic platform,where a single light-controlled wheeled robot travels in an activity landscape.Our experiments quantitatively demonstrate that the intrinsic pressure difference across the activity interface is balanced by the emerged polarization force.This result unambiguously confirms the theoretical predictions,thus validating the intrinsic pressure framework and laying the experimental foundation for the intrinsic pressure-based mechanical description of dry active matter.
基金supported by the National Natural Science Foundation of China(Grant Nos.52379107 and 52309141).
文摘The capillary pressure curve provides fundamental insights into the dynamics of fluid-fluid displacement and phase distributions.Capillary scaling is crucial for extrapolating capillary pressure-saturation data from laboratory tests to field applications.However,the classic scaling method fails to capture the effect of wettability as the pore surface approaches neutral wetting.Here,inspired by the role of pore-filling events in controlling fluid-fluid displacement,we perform a theoretical analysis of the burst events occurring during drainage processes.We find that the median threshold capillary pressure,which corresponds to the occurrence of burst events for the median pore throat,is closely correlated with the capillary pressure curve across various contact angles.Using this concept,we propose a new scaling method for capillary pressure curves under various wetting conditions.We conduct microfluidic experiments and pore-network modeling across different contact angles,porosities,and disorders to evaluate the new scaling methods,indicating that the new scaling method performs better than the Leverett J-function as the contact angle approaches 90°.We further perform geometry analysis on the critical radius of curvature for burst events in an ideal tetrahedral arrangement and extend the new scaling method to 3D(three-dimensional)porous media.Model evaluation shows that the 3D version of the scaling method also performs well but requires fewer parameters compared to the Leverett J-function.Our work enhances the prediction and interpretation of experimental data for capillary pressure curves under various wet conditions,and more importantly,establishes a methodology that relates Darcy-scale flow behavior to pore-scale fluid displacements.
基金PEEP titration in ARDS patients using EIT combined with lung ultrasound,Key Laboratory of Emergency Trauma Research,Ministry of Education (KLET-202201)airway clearance protocol in ICU mechanically ventilated patients based on electrical impedance imaging technology,Natural Science Foundation of Hunan Province (2024JJ9148)effects of end expiratory positive pressure on lung re-expansion in patients with ARDS and intra-abdominal hypertension monitored using lung ultrasound,Natural Science Foundation of Hunan Province (2023JJ60308)
文摘BACKGROUND:Individualized positive end-expiratory pressure(PEEP)titration is a crucial technique in mechanical ventilation therapy for acute respiratory distress syndrome(ARDS)patients with intra-abdominal hypertension(IAH).This study aimed to evaluate the eff ectiveness of electrical impedance tomography(EIT)-guided PEEP titration in this population.METHODS:This prospective study enrolled 36 ARDS patients,including 22 patients with IAH and 14 without IAH.All the patients underwent EIT-guided PEEP titration at the intersection point between alveolar overdistension and collapse during a decremental PEEP trial.The changes in pulmonary ventilation distribution,respiratory mechanics and hemodynamics during the titration process were observed.RESULTS:After EIT-guided PEEP titration was performed,the PEEP,peak inspiratory pressure and plateau pressure increased significantly(P<0.05).Furthermore,no significant differences were observed in respiratory system compliance,tidal volume,driving pressure,or the 4*DP+RR index between the two groups(P>0.05).The mechanical power increased in the non-IAH(NIAH)group after PEEP titration(P<0.05).Ventilation in gravity-dependent lung regions significantly increased(P<0.05),and the oxygenation index(PaO2/FiO2)improved signifi cantly(P<0.05)in both groups.However,blood pressure,heart rate,respiratory rate,central venous pressure,and lactate levels did not signifi cantly change.In the IAH group,the PaO2/FiO2 ratio improved less than that in the NIAH group did(P<0.05).CONCLUSION:In our study,individualized PEEP titration guided by EIT improved oxygenation in ARDS patients with concomitant IAH without signifi cantly aff ecting hemodynamics.The presence of IAH may limit the improvement of oxygenation during EIT-guided PEEP titration.
基金supported by the Basic Science Research Program(2023R1A2C3004336,RS-202300243807)&Regional Leading Research Center(RS-202400405278)through the National Research Foundation of Korea(NRF)grant funded by the Korea Government(MSIT)。
文摘Wearable sensors integrated with deep learning techniques have the potential to revolutionize seamless human-machine interfaces for real-time health monitoring,clinical diagnosis,and robotic applications.Nevertheless,it remains a critical challenge to simultaneously achieve desirable mechanical and electrical performance along with biocompatibility,adhesion,self-healing,and environmental robustness with excellent sensing metrics.Herein,we report a multifunctional,anti-freezing,selfadhesive,and self-healable organogel pressure sensor composed of cobalt nanoparticle encapsulated nitrogen-doped carbon nanotubes(CoN CNT)embedded in a polyvinyl alcohol-gelatin(PVA/GLE)matrix.Fabricated using a binary solvent system of water and ethylene glycol(EG),the CoN CNT/PVA/GLE organogel exhibits excellent flexibility,biocompatibility,and temperature tolerance with remarkable environmental stability.Electrochemical impedance spectroscopy confirms near-stable performance across a broad humidity range(40%-95%RH).Freeze-tolerant conductivity under sub-zero conditions(-20℃)is attributed to the synergistic role of CoN CNT and EG,preserving mobility and network integrity.The Co N CNT/PVA/GLE organogel sensor exhibits high sensitivity of 5.75 k Pa^(-1)in the detection range from 0 to 20 k Pa,ideal for subtle biomechanical motion detection.A smart human-machine interface for English letter recognition using deep learning achieved 98%accuracy.The organogel sensor utility was extended to detect human gestures like finger bending,wrist motion,and throat vibration during speech.
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.82192900,82192901,82192904,81390540,and 91846303 to L.L.)the National Key Research and Development Program of China(Grant No.2016YFC0900500 to Y.G.)the Kadoorie Charitable Foundation in Hong Kong,and the Wellcome Trust in the UK(Grant/Award Nos.088158/Z/09/Z,104085/Z/14/Z,and 202922/Z/16/Z to Z.C.).
文摘While a healthy lifestyle is known to reduce the risk of stroke,the extent to which blood pressure(BP)mediates this association remains unclear.The present study aimed to quantify the mediating role of BP in the association between combined lifestyle factors and stroke incidence.Using data from 51929 participants free of major cardiovascular diseases or cancer at baseline,we employed structural equation modeling to assess the mediating effects of systolic(SBP)and diastolic(DBP)blood pressure.During the follow-up,2811 incident stroke cases were identified.A healthy lifestyle was significantly associated with a reduced risk of stroke,with SBP mediating 44.70%(β=-0.0014,95%confidence interval[CI]:-0.0016 to-0.0012)and DBP mediating 37.81%(β=-0.0012,95%CI:-0.0015 to-0.0009)of this association.The mediating effects were attenuated but remained significant for ischemic stroke(SBP:33.21%;DBP:27.24%).In conclusion,approximately two-fifths of the protective association between a healthy lifestyle and stroke may be mediated by BP.These findings suggest that BP control may serve as an important early indicator for evaluating the effectiveness of lifestyle interventions in reducing stroke risk.
基金supported by National Natural Science Foundation of China(Nos.12432018,12372346)the Innovative Research Groups of the National Natural Science Foundation of China(No.12221002)National Natural Science Foundation of China(No.12302493)。
文摘Material phase-transition represents a significant phenomenon and mechanism in the context of hypervelocity protection.This study presents a thorough analysis of the phase-transition phenomena induced by shock pressure as the shock wave propagates initially to the rear of the projectile.The shock wave that induces a phase-transition is commonly referred to as a macroscopic phase-transition wave,whereas the interface that separates the distinct phases is referred to as macroscopic phase-boundary.The contact interface between the spherical projectile and the thin plate,characterized by its curved surface,plays a significant role in the nonlinear propagation and evolution of wave systems.The pressure distribution along the central axis of a spherical projectile is derived in accordance with the linear decay law observed for axial pressure.On this basis,a quadratic function is employed to characterize the trend of changes in wave front pressure,thereby facilitating the establishment of a model for wave front pressure distribution.Using the phase-transition pressure criterion for materials,the wave front phase evolution process is derived,and the macroscopic phase-boundary is determined.Based on the geometric propagation model(GPM)and the pressure distribution of the wave front,a phase geometric propagation model(PGPM)is proposed.The phase distribution of a spherical projectile impacting a thin plate is obtained by theoretical methods.The accuracy of the PGPM is subsequently validated through a comparison of its results with those obtained from numerical simulations.
文摘This study presents a numerical investigation of the transient relaxation dynamics of a near-critical CO_(2)droplet immersed in a warmer supercritical environment composed of the same fluid.Three thermodynamic regimes were analysed:quasi-critical(T_(r)=1.01,P_(r)=1.01),transitional(T_(r)=2.01,P_(r)=1.01),and deep supercritical(T_(r)=5.01,P_(r)=3.01).Theevolution of density,temperature,and velocity fieldswas examined to characterize the internal structure and stability of the interfacial transition layer.The evolution of density,temperature,and velocity fields highlights the competition between thermal diffusion,compressibility,andmass confinement in shaping the stability of the interfacial transition layer.Near the critical point,strong gradients and flux discontinuities emerge,consistent with known instabilities,whereas higher reduced conditions promote homogenization and stabilized transport.In the deep supercritical regime,smooth and nearly uniform fields indicate robust thermal stability.The model is validated against prior studies on droplet evaporation under supercritical and trans-critical conditions.Beyond theoretical insights,the results underline practical implications for advanced propulsion,heat transfer,and evaporation systems as well as for safe CO_(2)supercritical storage and extraction processes in energy,aerospace,pharmaceutical,and materials industries.
基金supported by Korea Evaluation Institute of Industrial Technology(KEIT)grant funded by the Korea Government(MOTIE)(RS-2022-00154720,Technology Innovation Program Development of next-generation power semiconductor based on Si-on-SiC structure)the National Research Foundation of Korea(NRF)by the Korea government(RS-2023-NR076826)Global-Learning&Academic Research Institution for Master's·PhD students,and Postdocs(LAMP)Program of the National Research Foundation of Korea(NRF)by the Ministry of Education(No.RS-2024-00443714).
文摘Improving device efficiency is fundamental for advancing energy harvesting technology,particularly in systems designed to convert light energy into electrical output.In our previous studies,we developed a basic structure light pressure electric generator(Basic-LPEG),which utilized a layered configuration of Ag/Pb(Zr,Ti)O_(3)(PZT)/Pt/GaAs to generate electricity based on light-induced pressure on the PZT.In this study,we sought to enhance the performance of this Basic-LPEG by introducing Ag nanoparticles/graphene oxide(AgNPs/GO)composite units(NP-LPEG),creating upgraded harvesting device.Specifically,by depositing the AgNPs/GO units twice onto the Basic-LPEG,we observed an increase in output voltage and current from 241 mV and 3.1μA to 310 mV and 9.3μA,respectively,under a solar simulator.The increase in electrical output directly correlated with the intensity of the light pressure impacting the PZT,as well as matched the Raman measurements,finite-difference time-domain simulations,and COMSOL Multiphysics Simulation.Experimental data revealed that the enhancement in electrical output was proportional to the number of hot spots generated between Ag nanoparticles,where the electric field experienced substantial amplification.These results underline the effectiveness of AgNPs/GO units in boosting the light-induced electric generation capacity,thereby providing a promising pathway for high-efficiency energy harvesting devices.
基金support from the Joint Funds of the National Natural Science Foundation of China(Grant No.U23A2060)the National Natural Science Foundation of China(Grant Nos.42177143 and 52474150).
文摘Drilling and blasting tunneling is a cyclic process in which tunnel rock undergoes repeated blast loading,affecting its dynamic characteristics,energy evolution,and damage progression.To explore the dynamic mechanical properties and damage mechanisms of carbonaceous slate under cyclic impact loads of varying intensities,cyclic dynamic tests are conducted using a triaxial split Hopkinson pressure bar.This study analyzes the stress-strain relationship,energy damage evolution,and macro-to-micro failure characteristics.The results show that peak stress and strain are significantly influenced by impact intensity and the number of impacts.The initial dynamic stress is positively correlated with the impact intensity,but with more impact,the dynamic stress decreases while the peak strain increases.Energy evolution follows a pattern of"slow growthfluctuating growthrapid growth,"with the crack initiation stress and its proportion decreasing.CT and SEM analyses reveal that as the impact intensity increases,failure becomes more chaotic,the fracture volume increases,and the fracture mode shifts from interlayer and intergranular to through-layer and trans-granular fractures.These findings provide an experimental basis for soft rock tunnel stability analysis.
文摘Accurate blood pressure(BP)monitoring is essential for preventing and managing cardiovascular disease.Advancements in materials science,medicine,flexible electronic,and artificial intelligence(AI)have enabled cuffless,unobtrusive BP monitoring systems,offering an alternative to traditional sphygmomanometers.However,extending these advances to real-world cardiovascular care particularly in resource-limited settings remains challenging due to constraints in computational resources,power efficiency,and deployment scalability.This review presents a comprehensive synthesis of AI-enhanced wearable BP monitoring,emphasizing its potential for personalized,scalable,and accessible healthcare.We systematically analyze the end-to-end system architecture,from mechano-electric sensing principles and AI-based estimation models to edge-aware deployment strategies tailored for low-resource environments.We further discuss clinical validation metrics and implementation barriers and prospective strategies.To bridge lab-to-field translation,we propose an innovative"sensor-model-deployment-assessment"co-design framework.This roadmap highlights how AI-enhanced BP technologies can support proactive hypertension control and promote cardiovascular health equity on a global scale.
基金supported by the National Natural Science Foundation of China(62301291,61904092,and 62181240278)Natural Science Foundation of Shandong Province(ZR2025MS1072)+1 种基金Youth Innovation Team Project of Shandong Provincial Education Department(2022KJ141)Taishan Scholars Project Special Funds(tsqn202312035)。
文摘Flexible pressure sensors(FPSs)offer unique benefits for fall detection and rehabilitation training,but conventional FPSs made from synthetic materials have drawbacks,including resource-heavy manufacturing,high costs,and environmental pollution.To address these limitations,this study proposes an innovative fabrication strategy for FPS based on natural materials.The upper and lower electrodes were made by treating a natural wood strip with a flame retardant,converting it into high-quality graphene via a costeffective infrared laser,and transferring it onto starch-based substrates.The dielectric layer was created by electrospinning a composite nanofiber membrane with cyclodextrin and carbon nanotubes.The resulting capacitive FPS shows high sensitivity(2.15 kPa^(-1) within 0-10 kPa),a low detection limit(~6.5 Pa),fast response and recovery times(29 and 39 ms),and excellent long-term stability(over 5000 cycles).It also demonstrates excellent biocompatibility(cell viability>98%)and fully degrades within 6 h.By integrating this sensor with wireless technology,a fall detection and rehabilitation monitoring system was developed.Data processing was handled by a Tiny Machine Learning module on a mobile platform,which transmitted relevant data to a cloud-based platform.The system accurately identified five common fall postures and assisted clinicians in guiding rehabilitation exercises,achieving recognition accuracies of 99%and 100%,respectively,offering a sustainable healthcare solution for the elderly.
