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 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
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
Objective:To investigate the antifibrotic effects of curcumin in a transverse aortic constriction(TAC)mouse model and elucidate its molecular mechanisms.Methods:Male C57BL/6 mice underwent TAC and received vehicle,low...Objective:To investigate the antifibrotic effects of curcumin in a transverse aortic constriction(TAC)mouse model and elucidate its molecular mechanisms.Methods:Male C57BL/6 mice underwent TAC and received vehicle,low-dose curcumin(50 mg/kg),high-dose curcumin(200 mg/kg),high-dose curcumin plus a scrambled control antagomir,or high-dose curcumin plus anti-miR-29b treatments.Cardiac function was assessed by echocardiography.Fibrosis was evaluated by histology,collagen volume fraction,and hydroxyproline content.Expression of miR-29b,HDAC4,and fibrosis-related markers(Col1a1,Col3a1,TGF-β1)was measured by quantitative RT-PCR and Western blotting assays.Myocardial procollagen type I carboxy-terminal propeptide was determined by ELISA,and HDAC4-specific enzymatic activity was assayed using a fluorogenic kit.Results:Curcumin improved cardiac function,reduced fibrosis,restored miR-29b expression,and suppressed HDAC4 expression and activity in a dose-dependent manner.Furthermore,curcumin decreased myocardial procollagen type I carboxy-terminal propeptide levels,confirming reduced collagen synthesis.Anti-miR-29b administration partially abrogated the antifibrotic and cardioprotective effects of curcumin.Conclusions:Curcumin attenuates pressure overload-induced cardiac fibrosis and dysfunction in a TAC mouse model via modulation of the miR-29b/HDAC4 axis and suppression of collagen synthesis.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
Freeze-thaw(F-T)cycle is receiving increasing attention as a primary threat to the long-term stability of rock engineering in high-elevation regions.In this study,artificial F-T cycle tests are first conducted on pre-...Freeze-thaw(F-T)cycle is receiving increasing attention as a primary threat to the long-term stability of rock engineering in high-elevation regions.In this study,artificial F-T cycle tests are first conducted on pre-flawed sandstone specimens with real-time frost heave pressure(FHP)monitoring,followed by subsequent cyclic loading tests with different maximum stresses.Given the water-ice-sandstone interaction,the evolution process of FHP in flaws can be divided into six phases,i.e.initial,silence,eruption,reduction,second-arising,and dissipation phases.Its magnitude exhibits an exponential decrease with increasing F-T cycle number.The influences of F-T cycles and the maximum stress on the fatigue mechanical characteristics of flawed sandstone are revealed.Subjected to higher F-T cycles and maximum stress,larger irreversible strain and less dissipated energy are accumulated inside flawed sandstone specimens,leading to faster damage and lower fatigue life.The three-stage evolution characters of irreversible strain and dissipated energy are both weakened by repeated F-T treatment,i.e.the prolonged initial and accelerated stages and shortened stable stage.In addition,the repeated F-T cycles diminish the impact of prefabricated flaws on cracking behavior of flawed sandstone specimens,and the fatigue failure pattern changes from shear-dominated failure with a transfixion shear band to tensile-dominated failure with massive tensile cracks as the F-T cycle number increases.Employing the scanning electron microscopy(SEM),the underlying damage mechanisms of flawed rocks under the coupling effect of F-T treatment and cyclic loading are discussed.Finally,an F-T-fatigue damage model is proposed based on FHP evolution and irreversible strain,which possesses distinct physical significance and reasonably quantifies the F-T deterioration and fatigue damage accumulation of flawed rocks.展开更多
A debris flow descending through an erodible convex colluvial bed,originating from a landslide dam and its upstream deposits,can entrain massive amounts of sediment,dramatically increasing the debris flow volume.Most ...A debris flow descending through an erodible convex colluvial bed,originating from a landslide dam and its upstream deposits,can entrain massive amounts of sediment,dramatically increasing the debris flow volume.Most existing erosion models assume that bed sediments are fully saturated,although this condition is rarely observed in nature.Therefore,a thorough understanding of debris flow overtopping erosion on a convex unsaturated bed is crucial for quantifying disaster risk.In this study,we experimentally investigated the effects of sediment composition,specifically coarse-grain size distribution and fine particle content,on the pore pressure evolution and entrainment of debris flows overriding a convex unsaturated colluvial bed.The average entrainment rate at convex sites for continuously graded bed sediment was higher than its discontinuous counterpart.The measured pore pressures within the unsaturated bed sediments were primarily generated by the passing debris flows.Furthermore,it was found that these pressures decreased as the fine particle content increased and the coarse-grain size of the erodible substrates decreased.When the coarse-grain size of the debris flow was smaller than that of the bed sediment,only a portion of the eroded material was entrained by the moving debris flow.In contrast,when the coarse-grain size of the debris flow was equal to or greater than that of the bed sediment,nearly all of the eroded material was entrained.The findings of this study could contribute to the assessment of hazard amplification and inform the design of mitigation and prevention strategies.展开更多
Background:Pressure injury(PI)is a prevalent complication in pediatric cardiac surgery,with higher incidence than in general pediatric populations due to children’s thin skin,underdeveloped subcutaneous tissue,and pr...Background:Pressure injury(PI)is a prevalent complication in pediatric cardiac surgery,with higher incidence than in general pediatric populations due to children’s thin skin,underdeveloped subcutaneous tissue,and prolonged intraoperative pressure.Objective:To evaluate the effectiveness of the curvilinear supine position(CSP)in preventing PI among children undergoing congenital heart disease(CHD)surgery.Methods:Between October 2024 and February 2025,a single-center randomized controlled trial was conducted.Of the 80 children initially enrolled for congenital heart disease(CHD)surgery,77(aged 1 month to 14 years)completed the study and were included in the final analysis after 3 were excluded due to protocol violations.Participants were randomly assigned to the CSP group(n=38)or the conventional supine position group(n=39).Results:The incidence of PI was significantly lower in the CSP group(2.6%)compared to the control group(20.5%)(p=0.029).Postoperative LDH levels were also significantly reduced in the CSP group(422.67±86.52 U/L vs.592.92±215.71 U/L;p=0.031),while preoperative LDH and surgical variables(e.g.,cardiopulmonary bypass time)were comparable between groups.Although the CSP group had a shorter hospital stay(17.24 vs.22.51 days),the difference was not statistically significant(p=0.085).Caregiver satisfaction was significantly higher in the CSP group(100.0%vs.84.6%;p=0.025).Conclusion:CSP effectively reduces PI incidence,mitigates tissue injury,and enhances caregiver satisfaction in pediatric cardiac surgery,offering a safe and feasible strategy for perioperative PI prevention.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
Objective Evidence suggests that depleted gut microbialα-diversity is associated with hypertension;however,whether metabolic markers affect this relationship remains unknown.We aimed to determine the potential metabo...Objective Evidence suggests that depleted gut microbialα-diversity is associated with hypertension;however,whether metabolic markers affect this relationship remains unknown.We aimed to determine the potential metabolites mediating the associations ofα-diversity with blood pressure(BP)and BP variability(BPV).Methods Metagenomics and plasma targeted metabolomics were conducted on 523 Chinese participants from the MetaSalt study.The 24-hour,daytime,and nighttime BP and BPV were calculated based on ambulatory BP measurements.Linear mixed models were used to characterize the relationships betweenα-diversity(Shannon and Chao1 index)and BP indices.Mediation analyses were performed to assess the contribution of metabolites to the observed associations.The influence of key metabolites on hypertension was further evaluated in a prospective cohort of 2,169 participants.Results Gut microbial richness(Chao1)was negatively associated with 24-hour systolic BP,daytime systolic BP,daytime diastolic BP,24-hour systolic BPV,and nighttime systolic BPV(P<0.05).Moreover,26 metabolites were strongly associated with richness(Bonferroni P<0.05).Among them,four key metabolites(imidazole propionate,2-hydroxy-3-methylbutyric acid,homovanillic acid,and hydrocinnamic acid)mediated the associations between richness and BP indices(proportions of mediating effects:14.1%–67.4%).These key metabolites were also associated with hypertension in the prospective cohort.For example,each 1-standard deviation unit increase in hydrocinnamic acid significantly reduced the risk of prevalent(OR[95%CI]=0.90[0.82,0.99];P=0.03)and incident hypertension(HR[95%CI]=0.83[0.71,0.96];P=0.01).Conclusion Our results suggest that gut microbial richness correlates with lower BP and BPV,and that certain metabolites mediate these associations.These findings provide novel insights into the pathogenesis and prevention of hypertension.展开更多
AIM:To assess the success rate of lacrimal sac hydrostatic pressure application(HPA)maneuver,a conservative office procedure for treatment of congenital nasolacrimal duct obstruction(CNLDO).METHODS:The medical records...AIM:To assess the success rate of lacrimal sac hydrostatic pressure application(HPA)maneuver,a conservative office procedure for treatment of congenital nasolacrimal duct obstruction(CNLDO).METHODS:The medical records of pediatric patients,36mo old or younger,diagnosed with CNLDO between the years 2016-2022,were retrospectively reviewed.In all children,HPA was performed by a pediatric ophthalmologist.Success was defined as the resolution of epiphora and discharge within 48h of the intervention.RESULTS:A total of 281 eyes(194 patients)with CNLDO underwent HPA.Follow-up data were available for 261 eyes(179 patients,50.3%male)and these patients were included in the analysis.The mean follow-up time was 11.6±13mo.Ninety-seven patients(54.2%)had unilateral nasolacrimal duct obstruction,while 82 patients(45.8%)had bilateral CNLDO.The mean age at the time of HPA was 5.8±5.9mo.Complete resolution of symptoms was achieved in 102(39.1%)eyes.Patients 6mo old or younger at the time of HPA had a significantly higher success rate compared to patients older than 6mo(43.7%vs 30.9%,P=0.04).Younger age at the time of pressure application was associated with a higher resolution rate of CNLDO(OR 0.93,P=0.004).Sex assigned at birth,prematurity,laterality of the obstruction and type of symptoms(epiphora,discharge)were not correlated with success.A second HPA was performed in 46 eyes,with resolution of symptoms in 12 eyes(26.1%).CONCLUSION:Hydrostatic pressure applied on the lacrimal sac by an experienced ophthalmologist or an experienced pediatrician may be an effective treatment for CNLDO.We recommend HPA as an initial active conservative approach in all pediatric patients with CNLDO,especially those younger than 6mo.展开更多
In order to investigate the effect of die wall thickness on morphologies of defect band,a stepped mold with a wall thickness of 5 mm,4 mm,3 mm,2 mm,and 1 mm was designed to carry out high pressure die casting experime...In order to investigate the effect of die wall thickness on morphologies of defect band,a stepped mold with a wall thickness of 5 mm,4 mm,3 mm,2 mm,and 1 mm was designed to carry out high pressure die casting experiments with AlSi10 MgMn alloy.For castings with wall thickness of 2-4 mm,the ratio of the mean defect band width(w)and mean grain size(d)in the defect band(w/d)ranges 7-18,while it increases to 24.47 for the 5 mm-thick casting.This difference is related with the filling speed and the distribution of externally solidified crystals(ESCs).The mold flow analysis indicates that the filling speed decreases from 25.41 m·s^(-1)to 11.07 m·s^(-1)when wall thickness increases from 2 mm to 5 mm.Due to the decreasing filling speed along the wall thickness,ESCs gradually diffuse from the center to the defect band,which keep the shear strength in the defect band at a high-level during filling.Meanwhile,the shear strength generated during the filling also decreases as the shear rate drops.Finally,the defect bands in the 5 mm-thick region become widen and indistinct,and the porosity is as high as 5.25%.展开更多
When a porous rock is subjected to overall compressive loading,either increasing pore pressure or decreasing confining pressure could result in rock failure.The stress path and the applied pressure change rate may aff...When a porous rock is subjected to overall compressive loading,either increasing pore pressure or decreasing confining pressure could result in rock failure.The stress path and the applied pressure change rate may affect the initiation and propagation of fractures within brittle materials.Understanding the physical mechanisms leading to failure is crucial for underground engineering applications and geo-energy exploration and storage.We conducted triaxial compression experiments on porous Bentheim sandstone samples at different stress paths and pressure change rates.First,at a constant confining pressure of 35 MPa and pore pressure of 5 MPa,intact cylindrical samples were axially loaded up to about 85%of the peak strength.Subsequently,the axial piston position was fixed,and then either the pore pressure was increased or the confining pressure was decreased at two different rates(0.5 MPa/min or 2 MPa/min),leading to final catastrophic failure.The mechanical results revealed that samples subjected to higher rates of decreasing effective confining pressure exhibited larger stress drop rates,higher slip rates,higher total breakdown work,higher rates of acoustic emissions(AEs)before failure,and higher post-failure AE decay rates.In contrast,the applied stress path did not significantly affect rock failure characteristics.Comparison of located AE events with post-mortem microstructures of deformed samples shows a good agreement.The AE source type determined from the P-wave first-motion polarity shows that shear failure dominated the fracture process when approaching failure.Gutenberg-Richter b-values revealed a significant decrease before failure in all tests.Our results indicate that,in contrast to the stress path,the rate of effective stress change strongly affects fracturing behavior and AE rate changes.展开更多
Estimating the properties of foam-conditioned clay soils is important for both conditioning and recycling goals in earth pressure balance(EPB)shield tunneling.In this study,the vacuum dewatering behaviors of foam-cond...Estimating the properties of foam-conditioned clay soils is important for both conditioning and recycling goals in earth pressure balance(EPB)shield tunneling.In this study,the vacuum dewatering behaviors of foam-conditioned clay soils were investigated,with their potential use as an alternative means to assess foam optimization being examined.A series of laboratory and fieldtests was conducted,including vacuum dewatering tests that considered the effects of filtrationtime and pressure,vane shear tests,and improved cone pullout tests under different gravimetric water content(w)and foam injection ratio(FIR)conditions.It was found that the filtrate loss(FL),which characterizes dewaterability,was increased by extended vacuum filtrationtime and elevated pressure.While increases in w and FIR enhanced FL,reductions were observed in the undrained shear strength(cu),tangential adhesion stress(Fs),and normal adhesion stress(Fn).Furthermore,a linear decrease in FL with increasing mechanical indices(cu,Fs,and Fn)was demonstrated by both laboratory and fielddata fittingresults,regardless of w,FIR,and dewatering conditions.This study provides novel insights into the understanding of vacuum dewatering mechanisms in foam-conditioned clay soils,while a simple approach is proposed for evaluating foam conditioning effectiveness in EPB shield tunneling applications.展开更多
Luminescent metal-organic frameworks(MOFs)have garnered significant attention due to their structural tunability and potential applications in solid-state lighting,bioimaging,sensing,anticounterfeiting,and other field...Luminescent metal-organic frameworks(MOFs)have garnered significant attention due to their structural tunability and potential applications in solid-state lighting,bioimaging,sensing,anticounterfeiting,and other fields.Nevertheless,due to the tendency of1,4-benzenedicarboxylic acid(BDC)to rotate within the framework,MOFs composed of it exhibit significant non-radiative energy dissipation and thus impair the emissive properties.In this study,efficient luminescence of MIL-140A nanocrystals(NCs)with BDC rotors as ligands is achieved by pressure treatment strategy.Pressure treatment effectively modulates the pore structure of the framework,enhancing the interactions between the N,N-dimethylformamide vip molecules and the BDC ligands.The enhanced host-vip interaction contributes to the structural rigidity of the MOF,thereby suppressing the rotation-induced excited-state energy loss.As a result,the pressure-treated MIL-140A NCs displayed bright blue-light emission,with the photoluminescence quantum yield increasing from an initial 6.8%to 69.2%.This study developed an effective strategy to improve the luminescence performance of rotor ligand MOFs,offers a new avenue for the rational design and synthesis of MOFs with superior luminescent properties.展开更多
Hydraulic stimulation technology is widely employed to enhance the permeability of geothermal reservoirs.Nevertheless,accurately predicting hydraulic fracture propagation in complex geological conditions remains chall...Hydraulic stimulation technology is widely employed to enhance the permeability of geothermal reservoirs.Nevertheless,accurately predicting hydraulic fracture propagation in complex geological conditions remains challenging,thereby hindering the effective utilization of existing natural fractures.In this study,a phase field model was developed utilizing the finite element method to examine the influence of fluid presence,stress conditions,and natural fractures on the initiation and propagation of hydraulic fractures.The model employs Biot's poroelasticity theory to establish the coupling between the displacement field and the fluid field,while the phase field theory is applied to simulate fracture behavior.The results show that whenσ_(x0)/σ_(y0)<3 or qf<20 kg/(m^(3)·s),the presence of natural fractures can alter the original propagation direction of hydraulic fractures.Conversely,in the absence of these conditions,the propagation path of natural fractures is predominantly influenced by the initial stress field.Furthermore,based on the analysis of breakdown pressure and damage area,the optimal intersection angle between natural fractures and hydraulic fractures is determined to range from 45°to 60°.Finally,once a dominant channel forms,initiating and propagating hydraulic fractures in other directions becomes increasingly difficult,even in highly fractured areas.This method tackles the challenges of initiating and propagating hydraulic fractures in complex geological conditions,providing a theoretical basis for optimizing Enhanced Geothermal System(EGS)projects.展开更多
The ability to generate high pressures in a large-volume press(LVP)is crucial for the study of matter under extreme conditions.Here,we have achieved ultrahigh pressures of and 50 GPa,respectively,at room temperature a...The ability to generate high pressures in a large-volume press(LVP)is crucial for the study of matter under extreme conditions.Here,we have achieved ultrahigh pressures of and 50 GPa,respectively,at room temperature and a high temperature of 1900 K∼60within a millimeter-sized sample volume in a Kawai-type LVP(KLVP)using hard tungsten carbide(WC)and newly designed assem-blies.The introduction of electroconductive polycrystalline boron-doped diamond and dense alumina wrapped with Cu foils into a large conventional cell assembly enables the detection of resistance variations in the Fe_(2)O_(3) pressure standard upon compression.The efficiency of pressure generation in the newly developed cell assembly equipped with conventional ZK10F WC anvils is significantly higher than that of conventional assemblies with some ultrahard or tapered WC anvils.Our study has enabled the routine gener-ation of pressures exceeding 50 GPa within a millimeter-sized sample chamber that have been inaccessible with traditional KLVPs.This advance in high-pressure technology not only breaks a record for pressure generation in traditional KLVPs,but also opens up new avenues for exploration of the properties of the Earth’s deep interior and for the synthesis of novel materials at extreme high pressures.展开更多
Portal hypertension is a critical determinant of prognosis in chronic liver disease and a key factor in evaluating candidates for liver transplantation.Traditional methods such as hepatic venous pressure gradient(HVPG...Portal hypertension is a critical determinant of prognosis in chronic liver disease and a key factor in evaluating candidates for liver transplantation.Traditional methods such as hepatic venous pressure gradient(HVPG)measurement have long been considered the gold standard for assessing portal pressure.However,these methods are invasive and carry procedural limitations.Recent advances in endoscopic ultrasound(EUS)-guided techniques have emerged as promising alternatives,offering direct and minimally invasive assessment of portal pressure.EUS-guided portal pressure gradient measurement enables real-time evaluation of haemodynamic through direct access to the portal system.This technique has shown to be as accurate as HVPG,and it has some extra benefits,like the ability to take liver biopsies and check collateral circulation all at the same time.Despite these benefits,the technique poses challenges such as operator dependence,proce-dural complexity,and limited standardization across centres.This minireview highlights the evolution of portal pressure measurement,focusing on the potential of EUS-guided techniques in pre-transplant assessment,risk strati-fication,and monitoring therapeutic outcomes.Furthermore,it discusses the technical challenges,clinical implications,and future directions for integrating these innovations into routine practice.Advances in portal pressure measurement hold significant promise for enhancing decision-making and outcomes in liver transplantation.展开更多
While injection-induced seismicity has been widely studied,its implications for CO_(2)geological storage require reevaluation due to distinct fluid-rock interactions.This study develops a coupled hydromechanical model...While injection-induced seismicity has been widely studied,its implications for CO_(2)geological storage require reevaluation due to distinct fluid-rock interactions.This study develops a coupled hydromechanical model incorporating rate-and-state friction laws to investigate fault reactivation mechanisms during early-stage CO_(2)injection.The competing effects of pore pressure diffusion and fluid pressurization are systematically investigated,considering three key factors:permeability variations within fault damage zones,normal stress variation coefficients,and injection parameters.Numerical simulations reveal that slower CO_(2)migration causes limited pressure perturbation(<0.3 MPa over 15 d)compared to single-phase fluid injection.Fluid pressurization enhances fault strength and delays reactivation,though this stabilizing effect diminishes in low-permeability damage zones.Highly permeable damage zones promote larger rupture areas despite strengthening from pressurization,as reduced effective stress accelerates failure.Paradoxically,while fluid pressurization increases fault strength,it simultaneously elevates seismic risk through amplified stress drops during slip events.Temporal analysis shows that fluid pressurization dominates initial fault response,while sustained pore pressure diffusion ultimately drives reactivation.Increased normal stress variation coefficients and injection rates accelerate localized rupture initiation but restrict propagation due to non-critically stressed states.This discrepancy demonstrates that regions with positive Coulomb failure stress changes do not correlate well with actual slip zones.These findings highlight the critical interplay between transient pressurization effects and progressive pressure diffusion during early CO_(2)injection phases,providing crucial insights for seismic risk management in CO_(2)storage projects.展开更多
In the scenario of a steam generator tube rupture accident in a lead-cooled fast reactor,secondary circuit subcooled water under high pressure is injected into an ordinary-pressure primary vessel,where a molten lead-b...In the scenario of a steam generator tube rupture accident in a lead-cooled fast reactor,secondary circuit subcooled water under high pressure is injected into an ordinary-pressure primary vessel,where a molten lead-based alloy(typically pure lead or lead-bismuth eutectic(LBE))is used as the coolant.To clarify the pressure build-up characteristics under water-jet injection,this study conducted several experiments by injecting pressurized water into a molten LBE pool at Sun Yat-sen University.To obtain a further understanding,several new experimental parameters were adopted,including the melt temperature,water subcooling,injection pressure,injection duration,and nozzle diameter.Through detailed analyses,it was found that the pressure and temperature during the water-melt interaction exhibited a consistent variation trend with our previous water-droplet injection mode LBE experiment.Similarly,the existence of a steam explosion was confirmed,which typically results in a much stronger pressure build-up.For the non-explosion cases,increasing the injection pressure,melt-pool temperature,nozzle diameter,and water subcooling promoted pressure build-up in the melt pool.However,a limited enhancement effect was observed when increasing the injection duration,which may be owing to the continually rising pressure in the interaction vessel or the isolation effect of the generated steam cavity.Regardless of whether a steam explosion occurred,the calculated mechanical and kinetic energy conversion efficiencies of the melt were relatively small(not exceeding 4.1%and 0.7%,respectively).Moreover,the range of the conversion efficiency was similar to that of previous water-droplet experiments,although the upper limit of the jet mode was slightly lower.展开更多
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.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 China International Medical Foundation(Z-2019-42-1908-4)Natural Science Basic Research Program of Shaanxi Province(2019JM-440).
文摘Objective:To investigate the antifibrotic effects of curcumin in a transverse aortic constriction(TAC)mouse model and elucidate its molecular mechanisms.Methods:Male C57BL/6 mice underwent TAC and received vehicle,low-dose curcumin(50 mg/kg),high-dose curcumin(200 mg/kg),high-dose curcumin plus a scrambled control antagomir,or high-dose curcumin plus anti-miR-29b treatments.Cardiac function was assessed by echocardiography.Fibrosis was evaluated by histology,collagen volume fraction,and hydroxyproline content.Expression of miR-29b,HDAC4,and fibrosis-related markers(Col1a1,Col3a1,TGF-β1)was measured by quantitative RT-PCR and Western blotting assays.Myocardial procollagen type I carboxy-terminal propeptide was determined by ELISA,and HDAC4-specific enzymatic activity was assayed using a fluorogenic kit.Results:Curcumin improved cardiac function,reduced fibrosis,restored miR-29b expression,and suppressed HDAC4 expression and activity in a dose-dependent manner.Furthermore,curcumin decreased myocardial procollagen type I carboxy-terminal propeptide levels,confirming reduced collagen synthesis.Anti-miR-29b administration partially abrogated the antifibrotic and cardioprotective effects of curcumin.Conclusions:Curcumin attenuates pressure overload-induced cardiac fibrosis and dysfunction in a TAC mouse model via modulation of the miR-29b/HDAC4 axis and suppression of collagen synthesis.
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 National Natural Science Foundation of China(Grant Nos.42377144,52225904 and 52039007)supported by the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘Freeze-thaw(F-T)cycle is receiving increasing attention as a primary threat to the long-term stability of rock engineering in high-elevation regions.In this study,artificial F-T cycle tests are first conducted on pre-flawed sandstone specimens with real-time frost heave pressure(FHP)monitoring,followed by subsequent cyclic loading tests with different maximum stresses.Given the water-ice-sandstone interaction,the evolution process of FHP in flaws can be divided into six phases,i.e.initial,silence,eruption,reduction,second-arising,and dissipation phases.Its magnitude exhibits an exponential decrease with increasing F-T cycle number.The influences of F-T cycles and the maximum stress on the fatigue mechanical characteristics of flawed sandstone are revealed.Subjected to higher F-T cycles and maximum stress,larger irreversible strain and less dissipated energy are accumulated inside flawed sandstone specimens,leading to faster damage and lower fatigue life.The three-stage evolution characters of irreversible strain and dissipated energy are both weakened by repeated F-T treatment,i.e.the prolonged initial and accelerated stages and shortened stable stage.In addition,the repeated F-T cycles diminish the impact of prefabricated flaws on cracking behavior of flawed sandstone specimens,and the fatigue failure pattern changes from shear-dominated failure with a transfixion shear band to tensile-dominated failure with massive tensile cracks as the F-T cycle number increases.Employing the scanning electron microscopy(SEM),the underlying damage mechanisms of flawed rocks under the coupling effect of F-T treatment and cyclic loading are discussed.Finally,an F-T-fatigue damage model is proposed based on FHP evolution and irreversible strain,which possesses distinct physical significance and reasonably quantifies the F-T deterioration and fatigue damage accumulation of flawed rocks.
基金supported by the National Key R&D Program of China(Grant No.2018YFC1505205)the Science and Technology Research Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(Grant No.IMHE-ZDRW-01)Sichuan Science and Technology Program(Grant No.2024NSFSC0781).
文摘A debris flow descending through an erodible convex colluvial bed,originating from a landslide dam and its upstream deposits,can entrain massive amounts of sediment,dramatically increasing the debris flow volume.Most existing erosion models assume that bed sediments are fully saturated,although this condition is rarely observed in nature.Therefore,a thorough understanding of debris flow overtopping erosion on a convex unsaturated bed is crucial for quantifying disaster risk.In this study,we experimentally investigated the effects of sediment composition,specifically coarse-grain size distribution and fine particle content,on the pore pressure evolution and entrainment of debris flows overriding a convex unsaturated colluvial bed.The average entrainment rate at convex sites for continuously graded bed sediment was higher than its discontinuous counterpart.The measured pore pressures within the unsaturated bed sediments were primarily generated by the passing debris flows.Furthermore,it was found that these pressures decreased as the fine particle content increased and the coarse-grain size of the erodible substrates decreased.When the coarse-grain size of the debris flow was smaller than that of the bed sediment,only a portion of the eroded material was entrained by the moving debris flow.In contrast,when the coarse-grain size of the debris flow was equal to or greater than that of the bed sediment,nearly all of the eroded material was entrained.The findings of this study could contribute to the assessment of hazard amplification and inform the design of mitigation and prevention strategies.
文摘Background:Pressure injury(PI)is a prevalent complication in pediatric cardiac surgery,with higher incidence than in general pediatric populations due to children’s thin skin,underdeveloped subcutaneous tissue,and prolonged intraoperative pressure.Objective:To evaluate the effectiveness of the curvilinear supine position(CSP)in preventing PI among children undergoing congenital heart disease(CHD)surgery.Methods:Between October 2024 and February 2025,a single-center randomized controlled trial was conducted.Of the 80 children initially enrolled for congenital heart disease(CHD)surgery,77(aged 1 month to 14 years)completed the study and were included in the final analysis after 3 were excluded due to protocol violations.Participants were randomly assigned to the CSP group(n=38)or the conventional supine position group(n=39).Results:The incidence of PI was significantly lower in the CSP group(2.6%)compared to the control group(20.5%)(p=0.029).Postoperative LDH levels were also significantly reduced in the CSP group(422.67±86.52 U/L vs.592.92±215.71 U/L;p=0.031),while preoperative LDH and surgical variables(e.g.,cardiopulmonary bypass time)were comparable between groups.Although the CSP group had a shorter hospital stay(17.24 vs.22.51 days),the difference was not statistically significant(p=0.085).Caregiver satisfaction was significantly higher in the CSP group(100.0%vs.84.6%;p=0.025).Conclusion:CSP effectively reduces PI incidence,mitigates tissue injury,and enhances caregiver satisfaction in pediatric cardiac surgery,offering a safe and feasible strategy for perioperative PI prevention.
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 the National Science and Technology Major Program for Noncommunicable Chronic Diseases(2023ZD0503500)the National Natural Science Foundation of China(82030102,12126602,91857118)+1 种基金the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences(2021-I2M-1-010,2019-I2M-2-003)the National High Level Hospital Clinical Research Funding(2022-GSP-GG-1,2022-GSP-GG-2)。
文摘Objective Evidence suggests that depleted gut microbialα-diversity is associated with hypertension;however,whether metabolic markers affect this relationship remains unknown.We aimed to determine the potential metabolites mediating the associations ofα-diversity with blood pressure(BP)and BP variability(BPV).Methods Metagenomics and plasma targeted metabolomics were conducted on 523 Chinese participants from the MetaSalt study.The 24-hour,daytime,and nighttime BP and BPV were calculated based on ambulatory BP measurements.Linear mixed models were used to characterize the relationships betweenα-diversity(Shannon and Chao1 index)and BP indices.Mediation analyses were performed to assess the contribution of metabolites to the observed associations.The influence of key metabolites on hypertension was further evaluated in a prospective cohort of 2,169 participants.Results Gut microbial richness(Chao1)was negatively associated with 24-hour systolic BP,daytime systolic BP,daytime diastolic BP,24-hour systolic BPV,and nighttime systolic BPV(P<0.05).Moreover,26 metabolites were strongly associated with richness(Bonferroni P<0.05).Among them,four key metabolites(imidazole propionate,2-hydroxy-3-methylbutyric acid,homovanillic acid,and hydrocinnamic acid)mediated the associations between richness and BP indices(proportions of mediating effects:14.1%–67.4%).These key metabolites were also associated with hypertension in the prospective cohort.For example,each 1-standard deviation unit increase in hydrocinnamic acid significantly reduced the risk of prevalent(OR[95%CI]=0.90[0.82,0.99];P=0.03)and incident hypertension(HR[95%CI]=0.83[0.71,0.96];P=0.01).Conclusion Our results suggest that gut microbial richness correlates with lower BP and BPV,and that certain metabolites mediate these associations.These findings provide novel insights into the pathogenesis and prevention of hypertension.
文摘AIM:To assess the success rate of lacrimal sac hydrostatic pressure application(HPA)maneuver,a conservative office procedure for treatment of congenital nasolacrimal duct obstruction(CNLDO).METHODS:The medical records of pediatric patients,36mo old or younger,diagnosed with CNLDO between the years 2016-2022,were retrospectively reviewed.In all children,HPA was performed by a pediatric ophthalmologist.Success was defined as the resolution of epiphora and discharge within 48h of the intervention.RESULTS:A total of 281 eyes(194 patients)with CNLDO underwent HPA.Follow-up data were available for 261 eyes(179 patients,50.3%male)and these patients were included in the analysis.The mean follow-up time was 11.6±13mo.Ninety-seven patients(54.2%)had unilateral nasolacrimal duct obstruction,while 82 patients(45.8%)had bilateral CNLDO.The mean age at the time of HPA was 5.8±5.9mo.Complete resolution of symptoms was achieved in 102(39.1%)eyes.Patients 6mo old or younger at the time of HPA had a significantly higher success rate compared to patients older than 6mo(43.7%vs 30.9%,P=0.04).Younger age at the time of pressure application was associated with a higher resolution rate of CNLDO(OR 0.93,P=0.004).Sex assigned at birth,prematurity,laterality of the obstruction and type of symptoms(epiphora,discharge)were not correlated with success.A second HPA was performed in 46 eyes,with resolution of symptoms in 12 eyes(26.1%).CONCLUSION:Hydrostatic pressure applied on the lacrimal sac by an experienced ophthalmologist or an experienced pediatrician may be an effective treatment for CNLDO.We recommend HPA as an initial active conservative approach in all pediatric patients with CNLDO,especially those younger than 6mo.
基金supported by the National Natural Science Foundation of China(No.52474396 and 52175284)the National Key Research and Development Program of China(Grant No.2022YFB3404201)。
文摘In order to investigate the effect of die wall thickness on morphologies of defect band,a stepped mold with a wall thickness of 5 mm,4 mm,3 mm,2 mm,and 1 mm was designed to carry out high pressure die casting experiments with AlSi10 MgMn alloy.For castings with wall thickness of 2-4 mm,the ratio of the mean defect band width(w)and mean grain size(d)in the defect band(w/d)ranges 7-18,while it increases to 24.47 for the 5 mm-thick casting.This difference is related with the filling speed and the distribution of externally solidified crystals(ESCs).The mold flow analysis indicates that the filling speed decreases from 25.41 m·s^(-1)to 11.07 m·s^(-1)when wall thickness increases from 2 mm to 5 mm.Due to the decreasing filling speed along the wall thickness,ESCs gradually diffuse from the center to the defect band,which keep the shear strength in the defect band at a high-level during filling.Meanwhile,the shear strength generated during the filling also decreases as the shear rate drops.Finally,the defect bands in the 5 mm-thick region become widen and indistinct,and the porosity is as high as 5.25%.
文摘When a porous rock is subjected to overall compressive loading,either increasing pore pressure or decreasing confining pressure could result in rock failure.The stress path and the applied pressure change rate may affect the initiation and propagation of fractures within brittle materials.Understanding the physical mechanisms leading to failure is crucial for underground engineering applications and geo-energy exploration and storage.We conducted triaxial compression experiments on porous Bentheim sandstone samples at different stress paths and pressure change rates.First,at a constant confining pressure of 35 MPa and pore pressure of 5 MPa,intact cylindrical samples were axially loaded up to about 85%of the peak strength.Subsequently,the axial piston position was fixed,and then either the pore pressure was increased or the confining pressure was decreased at two different rates(0.5 MPa/min or 2 MPa/min),leading to final catastrophic failure.The mechanical results revealed that samples subjected to higher rates of decreasing effective confining pressure exhibited larger stress drop rates,higher slip rates,higher total breakdown work,higher rates of acoustic emissions(AEs)before failure,and higher post-failure AE decay rates.In contrast,the applied stress path did not significantly affect rock failure characteristics.Comparison of located AE events with post-mortem microstructures of deformed samples shows a good agreement.The AE source type determined from the P-wave first-motion polarity shows that shear failure dominated the fracture process when approaching failure.Gutenberg-Richter b-values revealed a significant decrease before failure in all tests.Our results indicate that,in contrast to the stress path,the rate of effective stress change strongly affects fracturing behavior and AE rate changes.
基金supported by the National Youth Top-notch Talent Support Program of China(Grant No.00389335)the National Natural Science Foundation of China(Grant No.52378392)the“Foal Eagle Program”Youth Top-notch Talent Project of Fujian Province(Grant No.00387088).
文摘Estimating the properties of foam-conditioned clay soils is important for both conditioning and recycling goals in earth pressure balance(EPB)shield tunneling.In this study,the vacuum dewatering behaviors of foam-conditioned clay soils were investigated,with their potential use as an alternative means to assess foam optimization being examined.A series of laboratory and fieldtests was conducted,including vacuum dewatering tests that considered the effects of filtrationtime and pressure,vane shear tests,and improved cone pullout tests under different gravimetric water content(w)and foam injection ratio(FIR)conditions.It was found that the filtrate loss(FL),which characterizes dewaterability,was increased by extended vacuum filtrationtime and elevated pressure.While increases in w and FIR enhanced FL,reductions were observed in the undrained shear strength(cu),tangential adhesion stress(Fs),and normal adhesion stress(Fn).Furthermore,a linear decrease in FL with increasing mechanical indices(cu,Fs,and Fn)was demonstrated by both laboratory and fielddata fittingresults,regardless of w,FIR,and dewatering conditions.This study provides novel insights into the understanding of vacuum dewatering mechanisms in foam-conditioned clay soils,while a simple approach is proposed for evaluating foam conditioning effectiveness in EPB shield tunneling applications.
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406200)the National Natural Science Foundation of China(No.12274177 and 12304261)the China Postdoctoral Science Foundation(No.2024M751076)。
文摘Luminescent metal-organic frameworks(MOFs)have garnered significant attention due to their structural tunability and potential applications in solid-state lighting,bioimaging,sensing,anticounterfeiting,and other fields.Nevertheless,due to the tendency of1,4-benzenedicarboxylic acid(BDC)to rotate within the framework,MOFs composed of it exhibit significant non-radiative energy dissipation and thus impair the emissive properties.In this study,efficient luminescence of MIL-140A nanocrystals(NCs)with BDC rotors as ligands is achieved by pressure treatment strategy.Pressure treatment effectively modulates the pore structure of the framework,enhancing the interactions between the N,N-dimethylformamide vip molecules and the BDC ligands.The enhanced host-vip interaction contributes to the structural rigidity of the MOF,thereby suppressing the rotation-induced excited-state energy loss.As a result,the pressure-treated MIL-140A NCs displayed bright blue-light emission,with the photoluminescence quantum yield increasing from an initial 6.8%to 69.2%.This study developed an effective strategy to improve the luminescence performance of rotor ligand MOFs,offers a new avenue for the rational design and synthesis of MOFs with superior luminescent properties.
基金supported by the National Key Research and Development Program(2021YFB150740401)National Natural Science Foundation of China(42202336)the CAS Pioneer Hundred Talents Program in China(Y826031C01)。
文摘Hydraulic stimulation technology is widely employed to enhance the permeability of geothermal reservoirs.Nevertheless,accurately predicting hydraulic fracture propagation in complex geological conditions remains challenging,thereby hindering the effective utilization of existing natural fractures.In this study,a phase field model was developed utilizing the finite element method to examine the influence of fluid presence,stress conditions,and natural fractures on the initiation and propagation of hydraulic fractures.The model employs Biot's poroelasticity theory to establish the coupling between the displacement field and the fluid field,while the phase field theory is applied to simulate fracture behavior.The results show that whenσ_(x0)/σ_(y0)<3 or qf<20 kg/(m^(3)·s),the presence of natural fractures can alter the original propagation direction of hydraulic fractures.Conversely,in the absence of these conditions,the propagation path of natural fractures is predominantly influenced by the initial stress field.Furthermore,based on the analysis of breakdown pressure and damage area,the optimal intersection angle between natural fractures and hydraulic fractures is determined to range from 45°to 60°.Finally,once a dominant channel forms,initiating and propagating hydraulic fractures in other directions becomes increasingly difficult,even in highly fractured areas.This method tackles the challenges of initiating and propagating hydraulic fractures in complex geological conditions,providing a theoretical basis for optimizing Enhanced Geothermal System(EGS)projects.
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406200)the National Natural Science Foundation of China(Grant Nos.42272041 and 52302043)+2 种基金the National Natural Science Foundation of China(Grant No.U23A20561)the Jilin University High-level Innovation Team Foundation(Grant No.2021TD–05)the Shanghai Synchrotron Radiation Facility(Grant Nos.2024-SSRF-PT-510031 and 505511).
文摘The ability to generate high pressures in a large-volume press(LVP)is crucial for the study of matter under extreme conditions.Here,we have achieved ultrahigh pressures of and 50 GPa,respectively,at room temperature and a high temperature of 1900 K∼60within a millimeter-sized sample volume in a Kawai-type LVP(KLVP)using hard tungsten carbide(WC)and newly designed assem-blies.The introduction of electroconductive polycrystalline boron-doped diamond and dense alumina wrapped with Cu foils into a large conventional cell assembly enables the detection of resistance variations in the Fe_(2)O_(3) pressure standard upon compression.The efficiency of pressure generation in the newly developed cell assembly equipped with conventional ZK10F WC anvils is significantly higher than that of conventional assemblies with some ultrahard or tapered WC anvils.Our study has enabled the routine gener-ation of pressures exceeding 50 GPa within a millimeter-sized sample chamber that have been inaccessible with traditional KLVPs.This advance in high-pressure technology not only breaks a record for pressure generation in traditional KLVPs,but also opens up new avenues for exploration of the properties of the Earth’s deep interior and for the synthesis of novel materials at extreme high pressures.
文摘Portal hypertension is a critical determinant of prognosis in chronic liver disease and a key factor in evaluating candidates for liver transplantation.Traditional methods such as hepatic venous pressure gradient(HVPG)measurement have long been considered the gold standard for assessing portal pressure.However,these methods are invasive and carry procedural limitations.Recent advances in endoscopic ultrasound(EUS)-guided techniques have emerged as promising alternatives,offering direct and minimally invasive assessment of portal pressure.EUS-guided portal pressure gradient measurement enables real-time evaluation of haemodynamic through direct access to the portal system.This technique has shown to be as accurate as HVPG,and it has some extra benefits,like the ability to take liver biopsies and check collateral circulation all at the same time.Despite these benefits,the technique poses challenges such as operator dependence,proce-dural complexity,and limited standardization across centres.This minireview highlights the evolution of portal pressure measurement,focusing on the potential of EUS-guided techniques in pre-transplant assessment,risk strati-fication,and monitoring therapeutic outcomes.Furthermore,it discusses the technical challenges,clinical implications,and future directions for integrating these innovations into routine practice.Advances in portal pressure measurement hold significant promise for enhancing decision-making and outcomes in liver transplantation.
基金funded by Joint Funds of the National Natural Science Foundation of China(Grant No.U23A20671)the Major Project of Inner Mongolia Science and Technology(Grant No.2021ZD0034)the Creative Groups of Natural Science Foundation of Hubei Province,China(Grant No.2021CFA030).
文摘While injection-induced seismicity has been widely studied,its implications for CO_(2)geological storage require reevaluation due to distinct fluid-rock interactions.This study develops a coupled hydromechanical model incorporating rate-and-state friction laws to investigate fault reactivation mechanisms during early-stage CO_(2)injection.The competing effects of pore pressure diffusion and fluid pressurization are systematically investigated,considering three key factors:permeability variations within fault damage zones,normal stress variation coefficients,and injection parameters.Numerical simulations reveal that slower CO_(2)migration causes limited pressure perturbation(<0.3 MPa over 15 d)compared to single-phase fluid injection.Fluid pressurization enhances fault strength and delays reactivation,though this stabilizing effect diminishes in low-permeability damage zones.Highly permeable damage zones promote larger rupture areas despite strengthening from pressurization,as reduced effective stress accelerates failure.Paradoxically,while fluid pressurization increases fault strength,it simultaneously elevates seismic risk through amplified stress drops during slip events.Temporal analysis shows that fluid pressurization dominates initial fault response,while sustained pore pressure diffusion ultimately drives reactivation.Increased normal stress variation coefficients and injection rates accelerate localized rupture initiation but restrict propagation due to non-critically stressed states.This discrepancy demonstrates that regions with positive Coulomb failure stress changes do not correlate well with actual slip zones.These findings highlight the critical interplay between transient pressurization effects and progressive pressure diffusion during early CO_(2)injection phases,providing crucial insights for seismic risk management in CO_(2)storage projects.
基金supported by Basic and Applied Basic research foundation of Guangdong province(Nos.2021A1515010343 and 2022A1515011582)the Science and Technology Program of Guangdong Province(Nos.2021A0505030026 and 2022A0505050029).
文摘In the scenario of a steam generator tube rupture accident in a lead-cooled fast reactor,secondary circuit subcooled water under high pressure is injected into an ordinary-pressure primary vessel,where a molten lead-based alloy(typically pure lead or lead-bismuth eutectic(LBE))is used as the coolant.To clarify the pressure build-up characteristics under water-jet injection,this study conducted several experiments by injecting pressurized water into a molten LBE pool at Sun Yat-sen University.To obtain a further understanding,several new experimental parameters were adopted,including the melt temperature,water subcooling,injection pressure,injection duration,and nozzle diameter.Through detailed analyses,it was found that the pressure and temperature during the water-melt interaction exhibited a consistent variation trend with our previous water-droplet injection mode LBE experiment.Similarly,the existence of a steam explosion was confirmed,which typically results in a much stronger pressure build-up.For the non-explosion cases,increasing the injection pressure,melt-pool temperature,nozzle diameter,and water subcooling promoted pressure build-up in the melt pool.However,a limited enhancement effect was observed when increasing the injection duration,which may be owing to the continually rising pressure in the interaction vessel or the isolation effect of the generated steam cavity.Regardless of whether a steam explosion occurred,the calculated mechanical and kinetic energy conversion efficiencies of the melt were relatively small(not exceeding 4.1%and 0.7%,respectively).Moreover,the range of the conversion efficiency was similar to that of previous water-droplet experiments,although the upper limit of the jet mode was slightly lower.
