The work takes a new liquid-cooling plate in a power battery with pin fins inside the channel as the object.A mathematical model is established via the central composite design of the response surface to study the rel...The work takes a new liquid-cooling plate in a power battery with pin fins inside the channel as the object.A mathematical model is established via the central composite design of the response surface to study the relationships among the length,width,height,and spacing of pin fins;the maximum temperature and temperature difference of the battery module;and the pressure drop of the liquid-cooling plate.Model accuracy is verified via variance analysis.The new liquid-cooling plate enables the power battery to work within an optimal temperature range.Appropriately increasing the length,width,and height and reducing the spacing of pin fins could reduce the temperature of the power battery module and improve the temperature uniformity.However,the pressure drop of the liquid-cooling plate increases.The structural parameters of the pin fins are optimized to minimize the maximum temperature and the temperature difference of the battery module as well as the pressure drop of the liquid-cooling plate.The errors between the values predicted and actual by the simulation test are 0.58%,4%,and 0.48%,respectively,which further verifies the model accuracy.The results reveal the influence of the structural parameters of the pin fins inside the liquid-cooling plate on its heat dissipation performance and pressure drop characteristics.A theoretical basis is provided for the design of liquid-cooling plates in power batteries and the optimization of structural parameters.展开更多
Liquid hydrogen, known for its high energy density and eco-friendly properties, has garnered significant attention in the context of sustainable development and clean energy. A comprehensive understanding of its nucle...Liquid hydrogen, known for its high energy density and eco-friendly properties, has garnered significant attention in the context of sustainable development and clean energy. A comprehensive understanding of its nucleation mechanisms and boiling heat transfer characteristics is crucial. However, current experimental and macroscopic simulation methods offer limited insights. This study employs molecular dynamics simulations to investigate the vaporization nucleation and boiling heat transfer properties of liquid hydrogen at the microscopic scale, with a focus on the effects of hydrogen film thickness, surface temperature, and wettability. The results indicate that hydrogen film thickness plays a critical role in nucleation. Thinner layers disrupt the shape of liquid films, leading to increased errors, whereas a thickness of 7 nm ensures film stability. Different heating methods and temperatures influence nucleation in various ways. Rapid heating results in a higher heat flux, while an increase in temperature under the same heating method accelerates nucleation, resulting in earlier nucleation and enhanced surface heat flow. Surfaces with varying wettability levels exhibit distinct nucleation behaviors. Specifically, an increase in α delays nucleation, causing a shift from the surface to within the liquid film due to stronger solid–liquid interaction forces. This study offers a microscale perspective on the nucleation and boiling processes of liquid hydrogen and provides valuable insights for phase transition studies.展开更多
Polymer microfluidic chips are a common tool in biomedical research,and the production of mold inserts with microscale structures represents a crucial step in the precise molding of these chips.Electrical discharge ma...Polymer microfluidic chips are a common tool in biomedical research,and the production of mold inserts with microscale structures represents a crucial step in the precise molding of these chips.Electrical discharge machining(EDM)can achieve high-quality machining of microstructures on high-hardness mold steel inserts.This can reduce the manufacturing cost of microfluidic chip molds and extend the service life of molds.However,the EDM process is susceptible to the formation of poor-quality surfaces due to the occurrence of abnormal discharges.To address this issue,this paper presents in-depth research on a novel ultrasonic cavitation-assisted electrical discharge machining method.An ultrasonic transducer is placed in an electrical discharge working fluid to promote the removal of electrical corrosion products through the cavitation effect of the liquid.This can also reduce the occurrence of poor discharge,thereby improving the machining surface quality.The aluminum foil corrosion method is employed to investigate the distribution of ultrasonic action in the electric discharge working fluid.The attenuation law of ultrasonic action in the electric discharge working fluid is also investigated.The range of ultrasonic action is determined,providing a reference for subsequent ultrasonic vibration electric discharge working fluid processing experiments.The results of the aluminum foil tests are used to inform the selection of NAK80 mold steel as the experimental object.The effects of cavitation at three ultrasonic frequencies on the surface microstructure are investigated.The experimental results indicate that ultrasonic cavitation can facilitate the movement of corrosion products in electrical machining,reduce the occurrence of abnormal discharges caused by carbon deposition or the secondary re-melting of metals,and thereby enhance the machining surface quality.展开更多
To identify the species in liquid surface using mass spectrometry,we must eliminate or reduce interferences during the vaporization or desorption of the species from the liquid surface.It is much more challenging to i...To identify the species in liquid surface using mass spectrometry,we must eliminate or reduce interferences during the vaporization or desorption of the species from the liquid surface.It is much more challenging to isolate the ionic,larger species from the liquid surface,because of the frangible structures and the higher solvation energies of those species.Here we demonstrate a new mass spectrometry in which the ionic species at the liquid surface can be desorbed with ultrasoft infrared picosecond laser pulses while the liquid surface is not breached.This laser desorption assisted mass spectrometry is not only a powerful tool to detect the fragile species but also promising to investigate vibrational energy transfer dynamics in the liquid surface.展开更多
Atmospheric pressure plasma-liquid interactions exist in a variety of applications,including wastewater treatment,wound sterilization,and disinfection.In practice,the phenomenon of liquid surface depression will inevi...Atmospheric pressure plasma-liquid interactions exist in a variety of applications,including wastewater treatment,wound sterilization,and disinfection.In practice,the phenomenon of liquid surface depression will inevitably appear.The applied gas will cause a depression on the liquid surface,which will undoubtedly affect the plasma generation and further affect the application performance.However,the effect of liquid surface deformation on the plasma is still unclear.In this work,numerical models are developed to reveal the mechanism of liquid surface depressions affecting plasma discharge characteristics and the consequential distribution of plasma species,and further study the influence of liquid surface depressions of different sizes generated by different helium flow rates on the plasma.Results show that the liquid surface deformation changes the initial spatial electric field,resulting in the rearrangement of electrons on the liquid surface.The charges deposited on the liquid surface further increase the degree of distortion of the electric field.Moreover,the electric field and electron distribution affected by the liquid surface depression significantly influence the generation and distribution of active species,which determines the practical effectiveness of the relevant applications.This work explores the phenomenon of liquid surface depression,which has been neglected in previous related work,and contributes to further understanding of plasma-liquid interactions,providing better theoretical guidance for related applications and technologies.展开更多
To conduct extensive research on the application of ionic liquids as collectors in mineral flotation,ethanol(EtOH)was used as a solvent to dissolve hydrophobic ionic liquids(ILs)to simplify the reagent regime.Interest...To conduct extensive research on the application of ionic liquids as collectors in mineral flotation,ethanol(EtOH)was used as a solvent to dissolve hydrophobic ionic liquids(ILs)to simplify the reagent regime.Interesting phenomena were observed in which EtOH exerted different effects on the flotation efficiency of two ILs with similar structures.When EtOH was used to dissolve 1-dodecyl-3-methylimidazolium chloride(C12[mim]Cl)and as a collector for pure quartz flotation tests at a concentration of 1×10^(−5)mol·L^(−1),quartz recovery increased from 23.77%to 77.91%compared with ILs dissolved in water.However,quartz recovery of 1-dodecyl-3-methylim-idazolium hexafluorophosphate(C12[mim]PF6)decreased from 60.45%to 24.52%under the same conditions.The conditional experi-ments under 1×10^(−5)mol·L^(−1)ILs for EtOH concentration and under 2vol%EtOH for ILs concentration confirmed this difference.After being affected by EtOH,the mixed ore flotation tests of quartz and hematite showed a decrease in the hematite concentrate grade and re-covery for the C12[mim]Cl collector,whereas the hematite concentrate grade and recovery for the C12[mim]PF6 collector increased.On the basis of these differences and observations of flotation foam,two-phase bubble observation tests were carried out.The EtOH promoted the foam height of two ILs during aeration.It accelerated static froth defoaming after aeration stopped,and the foam of C12[mim]PF6 de-foaming especially quickly.In the discussion of flotation tests and foam observation,an attempt was made to explain the reasons and mechanisms behind the diverse phenomena using the dynamic surface tension effect and solvation effect results from EtOH.The solva-tion effect was verified through Fourier transform infrared(FT-IR),X-ray photoelectron spectroscopy(XPS),and Zeta potential tests.Al-though EtOH affects the adsorption of ILs on the ore surface during flotation negatively,it holds an positive value of inhibiting foam mer-ging during flotation aeration and accelerating the defoaming of static foam.And induce more robust secondary enrichment in the mixed ore flotation of the C12[mim]PF6 collector,facilitating effective mixed ore separation even under inhibitor-free conditions.展开更多
The presented study aims to reveal the effect of liquid temperature on cavitation-induced erosion of an Al-Mgalloy. An experimental work was conducted using a submerged cavitating waterjet to impact the specimen surfa...The presented study aims to reveal the effect of liquid temperature on cavitation-induced erosion of an Al-Mgalloy. An experimental work was conducted using a submerged cavitating waterjet to impact the specimen surface.For a certain cavitation number and a given standoff distance, different liquid temperatures were considered.Accordingly, a comprehensive comparison was implemented by inspecting the mass loss and surface morphologyof the tested specimens. The results show that the cumulative mass loss increases continuously with the liquidtemperature. A cavitation zone with an irregular profile becomes evident as the cavitation treatment proceeds.Increasing the temperature promotes the generation of cavitation bubbles. Large erosion pits are induced aftersevere material removal. The microhardness increases with the distance from the target surface. At a liquidtemperature of 50℃, the microhardness fluctuates apparently with increasing the depth of indentation.展开更多
In this work,we study the interaction between two colloidal particles in a liquid crystal that is in the isotropic phase.The interaction is caused by surface-induced polarization of the liquid crystal molecules in the...In this work,we study the interaction between two colloidal particles in a liquid crystal that is in the isotropic phase.The interaction is caused by surface-induced polarization of the liquid crystal molecules in the vicinity of the particles.We find that the interaction is short-ranged in both 2D and 3D geometry.Under symmetric homeotropic anchoring conditions,the interaction is repulsive.While under anti-symmetric homeotropic anchoring conditions,the interaction is repulsive at short distances but attractive at intermediate distances.The particle size has a strong impact on the effective interaction force.展开更多
In this work,the influences of surface layer slurry at different temperatures(10℃,14℃,18℃,22℃)on wax patterns deformation,shrinkage,slurry coating characteristics,and the surface quality of the casting were invest...In this work,the influences of surface layer slurry at different temperatures(10℃,14℃,18℃,22℃)on wax patterns deformation,shrinkage,slurry coating characteristics,and the surface quality of the casting were investigated by using a single factor variable method.The surface morphologies of the shell molds produced by different temperatures of the surface(first)layer slurries were observed via electron microscopy.Furthermore,the microscopic composition of these shell molds was obtained by EDS,and the osmotic effect of the slurry on the wax patterns at different temperatures was also assessed by the PZ-200 Contact Angle detector.The forming reasons for the surface cracks and holes of thick and large ZTC4 titanium alloy by investment casting were analyzed.The experimental results show that the surface of the shell molds prepared by the surface layer slurry with a low temperature exhibits noticeable damage,which is mainly due to the poor coating performance and the serious expansion and contraction of wax pattern at low temperatures.The second layer shell material(SiO_(2),Al_(2)O_(3))immerses into the crack area of the surface layer,contacts and reacts with the molten titanium to form surface cracks and holes in the castings.With the increase of the temperature of surface layer slurry,the damage to the shell surface tends to weaken,and the composition of the shell molds'surface becomes more uniform with less impurities.The results show that the surface layer slurry at 22℃is evenly coated on the surface of the wax patterns with appropriate thickness,and there is no surface shell mold rupture caused by sliding slurry after sand leaching.The surface layer slurry temperature is consistent with the wax pattern temperature and the workshop temperature,so there is no damage of the surface layer shell caused by expansion and contraction.Therefore,the shell mold prepared by the surface layer slurry at this temperature has good integrity,isolating the contact between the low inert shell material and the titanium liquid effectively,and the ZTC4 titanium alloy cylinder casting prepared by this shell mold is smooth,without cracks and holes.展开更多
Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the inte...Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the interface,further growth of hydrate due to the suction of water in the capillary system formed between the wall of the cuvette and the end boundary of the hydrate layer occurs.Most probably,substantial effects on the formation of this capillary system may be caused by variations in reactor wall properties,for example,hydrophobic-hydrophilic balance,roughness,etc.We found,that the rate of CO_(2) hydrate film growth on the surface of the humic acid aqueous solution is 4-fold to lower in comparison with the growth rate on the surface of pure water.We suppose that this is caused by the adsorption of humic acid associates on the surface of hydrate particles and,as a consequence,by the deceleration of the diffusion of dissolved carbon dioxide to the growing hydrate particle.展开更多
Liquid metals(LMs),because of their ability to remain in a liquid state at room temperature,render them highly versatile for applications in electronics,energy storage,medicine,and robotics.Among various LMs,Ga-based ...Liquid metals(LMs),because of their ability to remain in a liquid state at room temperature,render them highly versatile for applications in electronics,energy storage,medicine,and robotics.Among various LMs,Ga-based LMs exhibit minimal cytotoxicity,low viscosity,high thermal and electrical conductivities,and excellent wettability.Therefore,Ga-based LM composites(LMCs)have emerged as a recent research focus.Recent advancements have focused on novel fabrication techniques and applications spanning energy storage,flexible electronics,and biomedical devices.Particularly noteworthy are the developments in wearable sensors and electronic skins,which hold promise for healthcare monitoring and human-machine interfaces.Despite their potential,challenges,such as oxidative susceptibil-ity and biocompatibility,remain.Creating bio-based LMC materials is a promising approach to address these issues while exploring new avenues to optimize LMC performance and broaden its application domains.This review provides a concise overview of the recent trends in LMC research,highlights their transformative impacts,and outlines key directions for future investigation and development.展开更多
Ionic Liquid Electrospray Thrusters(ILETs)are well suited for micro-nano satellite applications due to their small size,low power consumption,and high specific impulse.However,the limited thrust of a single-emitter IL...Ionic Liquid Electrospray Thrusters(ILETs)are well suited for micro-nano satellite applications due to their small size,low power consumption,and high specific impulse.However,the limited thrust of a single-emitter ILET restricts its use in space missions.To optimize the performance of ILETs and make them suitable for a wider range of space missions,we designed a Circular-emitter ILET(CILET)to convert a one-dimensional(point)emission into a twodimensional(line)emission.The CILET can self-organize multiple Taylor cones simultaneously.The cones were photographed and the axial emission currents were measured under different voltage and pressure difference conditions with a CILET experimental system.The emission can be divided into two stable states and one unstable state based on the flow and current characteristics.The current in Stable state Ⅰ increases non-linearly with the voltage,while that in Stable state Ⅱ is nearly linear with respect to the voltage.The number of cones increases with the voltage in stable states,while the cones become short and crowded under high-voltage conditions.The variation law of the number of cones can be explained with the self-organization theory.The variation in the current exhibits a good correlation with the number of cones.This study demonstrates the feasibility of circular emitters and experimentally indicates that the emission current is improved by approximately two orders of magnitude compared to that of a single capillary.展开更多
The diffusion and dynamic behaviors of liquid metal droplet during impact significantly affect its application in 3D printing and painting processes.To obtain a better understanding of the impact process of liquid met...The diffusion and dynamic behaviors of liquid metal droplet during impact significantly affect its application in 3D printing and painting processes.To obtain a better understanding of the impact process of liquid metal droplets,we analyze the influence of different initial conditions and substrate materials on droplet spreading,impact force,and elastic wave propagation on the substrate.It is found that an agglomeration phenomenon can be observed when the liquid metal droplets impact onto a soft elastomer substrate,which is not observed as a metal substrate is employed.Regardless of the substrate material,when surface tension dominates the diffusion,the diffusion factor of droplets is proportional to We(Weber number).It is also observed that the self-similarity of liquid metal droplet impact force on copper substrates,which is not the case for soft elastomer substrates.Using smoothed particle hydrodynamics(SPH)simulations,the time-domain curve and peak point of the droplet can be well predicted for a metal substrate.Furthermore,by recording the acceleration signal on the substrates,we further obtain the energy radiated by elastic waves,providing an explanation for energy conversion during the impact process with varying parameters.The results provide an additional understanding on the complex impact behaviors of liquid metal droplets.展开更多
Sodium(Na)and magnesium(Mg)are becoming important for making energy-storage batteries and structural materials.Herein,we develop a liquid-metal-electrode-assisted electrolysis route to producing Na and Mg with low-car...Sodium(Na)and magnesium(Mg)are becoming important for making energy-storage batteries and structural materials.Herein,we develop a liquid-metal-electrode-assisted electrolysis route to producing Na and Mg with low-carbon emissions and no chlorine gas evolution.The clean production stems from the choice of a molten NaCl-Na_(2)CO_(3) electrolyte to prevent chlorine gas evolution,an inert nickel-based anode to produce oxygen,and a liquid metal cathode to make the cathodic product sit at the bottom of the electrolytic cell.We achieve a current efficiency of>90%for the electrolytic production of liquid Na-Sn alloy.Later,Mg-Sn alloy is prepared using the obtained Na-Sn alloy to displace Mg from molten NaCl-MgCl_(2) with a displacement efficiency of>96%.Further,Na and Mg are separated from the electrolytic Na-Sn and displaced Mg-Sn alloys by vacuum distillation with a recovery rate of>92%and Sn can be reused.Using this electrolysisdisplacement-distillation(EDD)approach,we prepare Mg from seawater.The CO_(2)emission of the EDD approach is~20.6 kg CO_(2)per kg Mg,which is less than that of the Australian Magnesium(AM)electrolysis process(~25.0 kg CO_(2)per kg Mg)and less than half that of the Pidgeon process(~45.2 kg CO_(2)per kg Mg).展开更多
Herein,the surface of Moso bamboo was hydrophobically modified by combining O_(2)/N_(2)plasma treatments with polydimethylsiloxane(PDMS)solution treatment as the hydrophobic solution.The effects of plasma treatment pr...Herein,the surface of Moso bamboo was hydrophobically modified by combining O_(2)/N_(2)plasma treatments with polydimethylsiloxane(PDMS)solution treatment as the hydrophobic solution.The effects of plasma treatment process(power and time),PDMS solution concentration,and maceration time on the hydrophobic performance of bamboo specimens were studied,and the optimal treatment conditions for improving the hydrophobicity were determined.Scanning electron microscopy(SEM),fourier transform infrared(FTIR),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS)were used to analyze the surface morphology,chemical structure,and functional groups in the specimens before and after the plasma and PDMS solution treatments under optimal conditions.Response surface analysis was also performed to determine the optimal treatment conditions.Results show that the hydrophobic performance of the Moso bamboo surface is effectively improved and the surface energy is reduced after the coordinated treatment.The optimal conditions for improving the hydrophobic performance of Moso bamboo surface are a treatment power of 800 W,treatment time of 15 s,O_(2)flow rate of 1.5 L/min,PDMS solution concentration of 5%,and maceration time of 60 min for O_(2)plasma treatment and a treatment power of 1000 W,treatment time of 15 s,N_(2)flow rate of 1.5 L/min,PDMS solution concentration of 5%,and maceration time of 60 min for N_(2)plasma treatment.After treatment,silicone oil particles and plasma etching traces are observed on the bamboo surface.Moreover,Si-O bonds in the PDMS solution are grafted to the bamboo surface via covalent bonds,thereby increasing the contact angle and decreasing the surface energy to achieve the hydrophobic effect.展开更多
Liquid leakage of pipeline networks not only results in considerableresource wastage but also leads to environmental pollution and ecological imbalance.In response to this global issue, a bioinspired superhydrophobic ...Liquid leakage of pipeline networks not only results in considerableresource wastage but also leads to environmental pollution and ecological imbalance.In response to this global issue, a bioinspired superhydrophobic thermoplastic polyurethane/carbon nanotubes/graphene nanosheets flexible strain sensor (TCGS) hasbeen developed using a combination of micro-extrusion compression molding andsurface modification for real-time wireless detection of liquid leakage. The TCGSutilizes the synergistic effects of Archimedean spiral crack arrays and micropores,which are inspired by the remarkable sensory capabilities of scorpions. This designachieves a sensitivity of 218.13 at a strain of 2%, which is an increase of 4300%. Additionally, it demonstrates exceptional durability bywithstanding over 5000 usage cycles. The robust superhydrophobicity of the TCGS significantly enhances sensitivity and stability indetecting small-scale liquid leakage, enabling precise monitoring of liquid leakage across a wide range of sizes, velocities, and compositionswhile issuing prompt alerts. This provides critical early warnings for both industrial pipelines and potential liquid leakage scenariosin everyday life. The development and utilization of bioinspired ultrasensitive flexible strain sensors offer an innovative and effectivesolution for the early wireless detection of liquid leakage.展开更多
In recent decades,capacitive pressure sensors(CPSs)with high sensitivity have demonstrated significant potential in applications such as medical monitoring,artificial intelligence,and soft robotics.Efforts to enhance ...In recent decades,capacitive pressure sensors(CPSs)with high sensitivity have demonstrated significant potential in applications such as medical monitoring,artificial intelligence,and soft robotics.Efforts to enhance this sensitivity have predominantly focused on material design and structural optimization,with surface microstructures such as wrinkles,pyramids,and micro-pillars proving effective.Although finite element modeling(FEM)has guided enhancements in CPS sensitivity across various surface designs,a theoretical understanding of sensitivity improvements remains underexplored.This paper employs sinusoidal wavy surfaces as a representative model to analytically elucidate the underlying mechanisms of sensitivity enhancement through contact mechanics.These theoretical insights are corroborated by FEM and experimental validations.Our findings underscore that optimizing material properties,such as Young’s modulus and relative permittivity,alongside adjustments in surface roughness and substrate thickness,can significantly elevate the sensitivity.The optimal performance is achieved when the amplitude-to-wavelength ratio(H/)is about 0.2.These results offer critical insights for designing ultrasensitive CPS devices,paving the way for advancements in sensor technology.展开更多
X-ray detectors show potential applications in medical imaging,materials science,and nuclear energy.To achieve high detection efficiency and spatial resolution,many conventional semiconductor materials,such as amorpho...X-ray detectors show potential applications in medical imaging,materials science,and nuclear energy.To achieve high detection efficiency and spatial resolution,many conventional semiconductor materials,such as amorphous selenium,cadmium telluride zinc,and perovskites,have been utilized in direct conversion X-ray detectors.However,these semiconductor materials are susceptible to temperature-induced performance degradation,crystallization,delamination,uneven lattice growth,radiation damage,and high dark current.This study explores a new approach by coupling an FC40 electronic fluorinated liquid with a specialized high-resolution and high-readout-speed complementary metal-oxide-semiconductor(CMOS)pixel array,specifically the Topmetal II−chip,to fabricate a direct conversion X-ray detector.The fluorinated liquid FC40(molecular formula:C_(21)F_(48)N_(2))is an electronic medium that is minimally affected by temperature and displays no issues with uniform conductivity.It exhibits a low dark current and minimal radiation damage and enables customizable thickness in X-ray absorption.This addresses the limitations inherent in conventional semiconductor-based detectors.In this study,simple X-ray detector imaging tests were conducted,demonstrating the excellent coupling capability between FC40 electronic fluorinated liquid and CMOS chips by the X-ray detector.A spatial resolution of 4.0 lp/mm was measured using a striped line par card,and a relatively clear image of a cockroach was displayed in the digital radiography imaging results.Preliminary test results indicated the feasibility of fabricating an X-ray detector by combining FC40 electronic fluorinated liquid and CMOS chips.Owing to the absence of issues related to chip-material coupling,a high spatial resolution could be achieved by reducing the chip pixel size.This method presents a new avenue for studies on novel liquid-based direct conversion X-ray detectors.展开更多
To more accurately describe the coal damage and fracture evolution law during liquid nitrogen(LN_(2))fracturing under true triaxial stress,a thermal-hydraulic-mechanical-damage(THMD)coupling model for LN_(2) fracturin...To more accurately describe the coal damage and fracture evolution law during liquid nitrogen(LN_(2))fracturing under true triaxial stress,a thermal-hydraulic-mechanical-damage(THMD)coupling model for LN_(2) fracturing coal was developed,considering the coal heterogeneity and thermophysical parameters of nitrogen.The accuracy and applicability of model were verified by comparing with LN_(2) injection pre-cooling and fracturing experimental data.The effects of different pre-cooling times and horizontal stress ratios on coal damage evolution,permeability,temperature distribution,and fracture characteristics were analyzed.The results show that the permeability and damage of the coal increase exponentially,while the temperature decreases exponentially during the fracturing process.As the pre-cooling time increases,the damage range of the coal expands,and the fracture propagation becomes more pronounced.The initiation pressure and rupture pressure decrease and tend to stabilize with longer precooling times.As the horizontal stress ratio increases,fractures preferentially extend along the direction of maximum horizontal principal stress,leading to a significant decrease in both initiation and rupture pressures.At a horizontal stress ratio of 3,the initiation pressure drops by 48.07%,and the rupture pressure decreases by 41.36%.The results provide a theoretical basis for optimizing LN_(2) fracturing techniques and improving coal seam modification.展开更多
The roughness of the fracture surface directly affects the strength,deformation,and permeability of the surrounding rock in deep underground engineering.Understanding the effect of high temperature and thermal cycle o...The roughness of the fracture surface directly affects the strength,deformation,and permeability of the surrounding rock in deep underground engineering.Understanding the effect of high temperature and thermal cycle on the fracture surface roughness plays an important role in estimating the damage degree and stability of deep rock mass.In this paper,the variations of fracture surface roughness of granite after different heating and thermal cycles were investigated using the joint roughness coefficient method(JRC),three-dimensional(3D)roughness parameters,and fractal dimension(D),and the mechanism of damage and deterioration of granite were revealed.The experimental results show an increase in the roughness of the granite fracture surface as temperature and cycle number were incremented.The variations of JRC,height parameter,inclination parameter and area parameter with the temperature conformed to the Boltzmann's functional distribution,while the D decreased linearly as the temperature increased.Besides,the anisotropy index(Ip)of the granite fracture surface increased as the temperature increased,and the larger parameter values of roughness characterization at different temperatures were attained mainly in directions of 20°–40°,60°–100°and 140°–160°.The fracture aperture of granite after fracture followed the Gauss distribution and the average aperture increased with increasing temperature,which increased from 0.665 mm at 25℃to 1.058 mm at 800℃.High temperature caused an uneven thermal expansion,water evaporation,and oxidation of minerals within the granite,which promoted the growth and expansion of microfractures,and reduced interparticle bonding strength.In particular,the damage was exacerbated by the expansion and cracking of the quartz phase transition after T>500℃.Thermal cycles contributed to the accumulation of this damage and further weakened the interparticle bonding forces,resulting in a significant increase in the roughness,anisotropy,and aperture of the fracture surface after five cycles.展开更多
基金supported by the Education and Teaching Research Project of Universities in Fujian Province(FBJY20230167).
文摘The work takes a new liquid-cooling plate in a power battery with pin fins inside the channel as the object.A mathematical model is established via the central composite design of the response surface to study the relationships among the length,width,height,and spacing of pin fins;the maximum temperature and temperature difference of the battery module;and the pressure drop of the liquid-cooling plate.Model accuracy is verified via variance analysis.The new liquid-cooling plate enables the power battery to work within an optimal temperature range.Appropriately increasing the length,width,and height and reducing the spacing of pin fins could reduce the temperature of the power battery module and improve the temperature uniformity.However,the pressure drop of the liquid-cooling plate increases.The structural parameters of the pin fins are optimized to minimize the maximum temperature and the temperature difference of the battery module as well as the pressure drop of the liquid-cooling plate.The errors between the values predicted and actual by the simulation test are 0.58%,4%,and 0.48%,respectively,which further verifies the model accuracy.The results reveal the influence of the structural parameters of the pin fins inside the liquid-cooling plate on its heat dissipation performance and pressure drop characteristics.A theoretical basis is provided for the design of liquid-cooling plates in power batteries and the optimization of structural parameters.
基金supported by the Youth Innovation Project of the Natural Science Foundation of Fujian Province(No.2022J05164)the Natural Science Foundation Youth Project of Xiamen Municipal Bureau of Science and Technology(No.3502Z20227047)+1 种基金the Scientific Research Foundation of Jimei University,China(No.ZQ2021053)the Fujian Provincial Department of Education,China(No.JAT210222).
文摘Liquid hydrogen, known for its high energy density and eco-friendly properties, has garnered significant attention in the context of sustainable development and clean energy. A comprehensive understanding of its nucleation mechanisms and boiling heat transfer characteristics is crucial. However, current experimental and macroscopic simulation methods offer limited insights. This study employs molecular dynamics simulations to investigate the vaporization nucleation and boiling heat transfer properties of liquid hydrogen at the microscopic scale, with a focus on the effects of hydrogen film thickness, surface temperature, and wettability. The results indicate that hydrogen film thickness plays a critical role in nucleation. Thinner layers disrupt the shape of liquid films, leading to increased errors, whereas a thickness of 7 nm ensures film stability. Different heating methods and temperatures influence nucleation in various ways. Rapid heating results in a higher heat flux, while an increase in temperature under the same heating method accelerates nucleation, resulting in earlier nucleation and enhanced surface heat flow. Surfaces with varying wettability levels exhibit distinct nucleation behaviors. Specifically, an increase in α delays nucleation, causing a shift from the surface to within the liquid film due to stronger solid–liquid interaction forces. This study offers a microscale perspective on the nucleation and boiling processes of liquid hydrogen and provides valuable insights for phase transition studies.
基金supported by the Higher Education Science and Technology Innovation Project of Shanxi Province(No.2022L706)Natural Science Foundation of Jiangsu Province(No.BK20210755).
文摘Polymer microfluidic chips are a common tool in biomedical research,and the production of mold inserts with microscale structures represents a crucial step in the precise molding of these chips.Electrical discharge machining(EDM)can achieve high-quality machining of microstructures on high-hardness mold steel inserts.This can reduce the manufacturing cost of microfluidic chip molds and extend the service life of molds.However,the EDM process is susceptible to the formation of poor-quality surfaces due to the occurrence of abnormal discharges.To address this issue,this paper presents in-depth research on a novel ultrasonic cavitation-assisted electrical discharge machining method.An ultrasonic transducer is placed in an electrical discharge working fluid to promote the removal of electrical corrosion products through the cavitation effect of the liquid.This can also reduce the occurrence of poor discharge,thereby improving the machining surface quality.The aluminum foil corrosion method is employed to investigate the distribution of ultrasonic action in the electric discharge working fluid.The attenuation law of ultrasonic action in the electric discharge working fluid is also investigated.The range of ultrasonic action is determined,providing a reference for subsequent ultrasonic vibration electric discharge working fluid processing experiments.The results of the aluminum foil tests are used to inform the selection of NAK80 mold steel as the experimental object.The effects of cavitation at three ultrasonic frequencies on the surface microstructure are investigated.The experimental results indicate that ultrasonic cavitation can facilitate the movement of corrosion products in electrical machining,reduce the occurrence of abnormal discharges caused by carbon deposition or the secondary re-melting of metals,and thereby enhance the machining surface quality.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0450202).
文摘To identify the species in liquid surface using mass spectrometry,we must eliminate or reduce interferences during the vaporization or desorption of the species from the liquid surface.It is much more challenging to isolate the ionic,larger species from the liquid surface,because of the frangible structures and the higher solvation energies of those species.Here we demonstrate a new mass spectrometry in which the ionic species at the liquid surface can be desorbed with ultrasoft infrared picosecond laser pulses while the liquid surface is not breached.This laser desorption assisted mass spectrometry is not only a powerful tool to detect the fragile species but also promising to investigate vibrational energy transfer dynamics in the liquid surface.
基金supported by National Natural Science Foundation of China(No.52377145).
文摘Atmospheric pressure plasma-liquid interactions exist in a variety of applications,including wastewater treatment,wound sterilization,and disinfection.In practice,the phenomenon of liquid surface depression will inevitably appear.The applied gas will cause a depression on the liquid surface,which will undoubtedly affect the plasma generation and further affect the application performance.However,the effect of liquid surface deformation on the plasma is still unclear.In this work,numerical models are developed to reveal the mechanism of liquid surface depressions affecting plasma discharge characteristics and the consequential distribution of plasma species,and further study the influence of liquid surface depressions of different sizes generated by different helium flow rates on the plasma.Results show that the liquid surface deformation changes the initial spatial electric field,resulting in the rearrangement of electrons on the liquid surface.The charges deposited on the liquid surface further increase the degree of distortion of the electric field.Moreover,the electric field and electron distribution affected by the liquid surface depression significantly influence the generation and distribution of active species,which determines the practical effectiveness of the relevant applications.This work explores the phenomenon of liquid surface depression,which has been neglected in previous related work,and contributes to further understanding of plasma-liquid interactions,providing better theoretical guidance for related applications and technologies.
基金supported by the National Natural Science Foundation of China(No.51874221)the Open Foundation of Guangxi Key Laboratory of Processing for Nonferrous Metals and Featured Materials,Guangxi University(No.2022GXYSOF 11).
文摘To conduct extensive research on the application of ionic liquids as collectors in mineral flotation,ethanol(EtOH)was used as a solvent to dissolve hydrophobic ionic liquids(ILs)to simplify the reagent regime.Interesting phenomena were observed in which EtOH exerted different effects on the flotation efficiency of two ILs with similar structures.When EtOH was used to dissolve 1-dodecyl-3-methylimidazolium chloride(C12[mim]Cl)and as a collector for pure quartz flotation tests at a concentration of 1×10^(−5)mol·L^(−1),quartz recovery increased from 23.77%to 77.91%compared with ILs dissolved in water.However,quartz recovery of 1-dodecyl-3-methylim-idazolium hexafluorophosphate(C12[mim]PF6)decreased from 60.45%to 24.52%under the same conditions.The conditional experi-ments under 1×10^(−5)mol·L^(−1)ILs for EtOH concentration and under 2vol%EtOH for ILs concentration confirmed this difference.After being affected by EtOH,the mixed ore flotation tests of quartz and hematite showed a decrease in the hematite concentrate grade and re-covery for the C12[mim]Cl collector,whereas the hematite concentrate grade and recovery for the C12[mim]PF6 collector increased.On the basis of these differences and observations of flotation foam,two-phase bubble observation tests were carried out.The EtOH promoted the foam height of two ILs during aeration.It accelerated static froth defoaming after aeration stopped,and the foam of C12[mim]PF6 de-foaming especially quickly.In the discussion of flotation tests and foam observation,an attempt was made to explain the reasons and mechanisms behind the diverse phenomena using the dynamic surface tension effect and solvation effect results from EtOH.The solva-tion effect was verified through Fourier transform infrared(FT-IR),X-ray photoelectron spectroscopy(XPS),and Zeta potential tests.Al-though EtOH affects the adsorption of ILs on the ore surface during flotation negatively,it holds an positive value of inhibiting foam mer-ging during flotation aeration and accelerating the defoaming of static foam.And induce more robust secondary enrichment in the mixed ore flotation of the C12[mim]PF6 collector,facilitating effective mixed ore separation even under inhibitor-free conditions.
基金grateful for thefinancial support of National Natural Science Foundation of China(Grant Nos.52311540154 and 52175410).
文摘The presented study aims to reveal the effect of liquid temperature on cavitation-induced erosion of an Al-Mgalloy. An experimental work was conducted using a submerged cavitating waterjet to impact the specimen surface.For a certain cavitation number and a given standoff distance, different liquid temperatures were considered.Accordingly, a comprehensive comparison was implemented by inspecting the mass loss and surface morphologyof the tested specimens. The results show that the cumulative mass loss increases continuously with the liquidtemperature. A cavitation zone with an irregular profile becomes evident as the cavitation treatment proceeds.Increasing the temperature promotes the generation of cavitation bubbles. Large erosion pits are induced aftersevere material removal. The microhardness increases with the distance from the target surface. At a liquidtemperature of 50℃, the microhardness fluctuates apparently with increasing the depth of indentation.
基金support from the National Natural Science Foundation of China under Grant No.12004317Fundamental Research Funds for Central Universities of China under Grant No.20720200072111 project No.B16029.
文摘In this work,we study the interaction between two colloidal particles in a liquid crystal that is in the isotropic phase.The interaction is caused by surface-induced polarization of the liquid crystal molecules in the vicinity of the particles.We find that the interaction is short-ranged in both 2D and 3D geometry.Under symmetric homeotropic anchoring conditions,the interaction is repulsive.While under anti-symmetric homeotropic anchoring conditions,the interaction is repulsive at short distances but attractive at intermediate distances.The particle size has a strong impact on the effective interaction force.
文摘In this work,the influences of surface layer slurry at different temperatures(10℃,14℃,18℃,22℃)on wax patterns deformation,shrinkage,slurry coating characteristics,and the surface quality of the casting were investigated by using a single factor variable method.The surface morphologies of the shell molds produced by different temperatures of the surface(first)layer slurries were observed via electron microscopy.Furthermore,the microscopic composition of these shell molds was obtained by EDS,and the osmotic effect of the slurry on the wax patterns at different temperatures was also assessed by the PZ-200 Contact Angle detector.The forming reasons for the surface cracks and holes of thick and large ZTC4 titanium alloy by investment casting were analyzed.The experimental results show that the surface of the shell molds prepared by the surface layer slurry with a low temperature exhibits noticeable damage,which is mainly due to the poor coating performance and the serious expansion and contraction of wax pattern at low temperatures.The second layer shell material(SiO_(2),Al_(2)O_(3))immerses into the crack area of the surface layer,contacts and reacts with the molten titanium to form surface cracks and holes in the castings.With the increase of the temperature of surface layer slurry,the damage to the shell surface tends to weaken,and the composition of the shell molds'surface becomes more uniform with less impurities.The results show that the surface layer slurry at 22℃is evenly coated on the surface of the wax patterns with appropriate thickness,and there is no surface shell mold rupture caused by sliding slurry after sand leaching.The surface layer slurry temperature is consistent with the wax pattern temperature and the workshop temperature,so there is no damage of the surface layer shell caused by expansion and contraction.Therefore,the shell mold prepared by the surface layer slurry at this temperature has good integrity,isolating the contact between the low inert shell material and the titanium liquid effectively,and the ZTC4 titanium alloy cylinder casting prepared by this shell mold is smooth,without cracks and holes.
基金supported by the Russian Science Foundation(23-29-00830).
文摘Morphology and growth rate of carbon dioxide hydrate on the interface between liquid carbon dioxide and humic acid solutions were studied in this work.It was found that after the growth of the hydrate film at the interface,further growth of hydrate due to the suction of water in the capillary system formed between the wall of the cuvette and the end boundary of the hydrate layer occurs.Most probably,substantial effects on the formation of this capillary system may be caused by variations in reactor wall properties,for example,hydrophobic-hydrophilic balance,roughness,etc.We found,that the rate of CO_(2) hydrate film growth on the surface of the humic acid aqueous solution is 4-fold to lower in comparison with the growth rate on the surface of pure water.We suppose that this is caused by the adsorption of humic acid associates on the surface of hydrate particles and,as a consequence,by the deceleration of the diffusion of dissolved carbon dioxide to the growing hydrate particle.
基金supported by the GRDC(Global Research Development Center)Cooperative Hub Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Science and ICT(MSIT)(No.RS-2023-00257595).
文摘Liquid metals(LMs),because of their ability to remain in a liquid state at room temperature,render them highly versatile for applications in electronics,energy storage,medicine,and robotics.Among various LMs,Ga-based LMs exhibit minimal cytotoxicity,low viscosity,high thermal and electrical conductivities,and excellent wettability.Therefore,Ga-based LM composites(LMCs)have emerged as a recent research focus.Recent advancements have focused on novel fabrication techniques and applications spanning energy storage,flexible electronics,and biomedical devices.Particularly noteworthy are the developments in wearable sensors and electronic skins,which hold promise for healthcare monitoring and human-machine interfaces.Despite their potential,challenges,such as oxidative susceptibil-ity and biocompatibility,remain.Creating bio-based LMC materials is a promising approach to address these issues while exploring new avenues to optimize LMC performance and broaden its application domains.This review provides a concise overview of the recent trends in LMC research,highlights their transformative impacts,and outlines key directions for future investigation and development.
基金co-supported by the National Key R&D Program of China(No.2020YFC2201001)the Shenzhen Science and Technology Program,China(No.20210623091808026)。
文摘Ionic Liquid Electrospray Thrusters(ILETs)are well suited for micro-nano satellite applications due to their small size,low power consumption,and high specific impulse.However,the limited thrust of a single-emitter ILET restricts its use in space missions.To optimize the performance of ILETs and make them suitable for a wider range of space missions,we designed a Circular-emitter ILET(CILET)to convert a one-dimensional(point)emission into a twodimensional(line)emission.The CILET can self-organize multiple Taylor cones simultaneously.The cones were photographed and the axial emission currents were measured under different voltage and pressure difference conditions with a CILET experimental system.The emission can be divided into two stable states and one unstable state based on the flow and current characteristics.The current in Stable state Ⅰ increases non-linearly with the voltage,while that in Stable state Ⅱ is nearly linear with respect to the voltage.The number of cones increases with the voltage in stable states,while the cones become short and crowded under high-voltage conditions.The variation law of the number of cones can be explained with the self-organization theory.The variation in the current exhibits a good correlation with the number of cones.This study demonstrates the feasibility of circular emitters and experimentally indicates that the emission current is improved by approximately two orders of magnitude compared to that of a single capillary.
基金supported by the National Natural Science Foundation of China(Grant No.12211530061)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LD22A020001)。
文摘The diffusion and dynamic behaviors of liquid metal droplet during impact significantly affect its application in 3D printing and painting processes.To obtain a better understanding of the impact process of liquid metal droplets,we analyze the influence of different initial conditions and substrate materials on droplet spreading,impact force,and elastic wave propagation on the substrate.It is found that an agglomeration phenomenon can be observed when the liquid metal droplets impact onto a soft elastomer substrate,which is not observed as a metal substrate is employed.Regardless of the substrate material,when surface tension dominates the diffusion,the diffusion factor of droplets is proportional to We(Weber number).It is also observed that the self-similarity of liquid metal droplet impact force on copper substrates,which is not the case for soft elastomer substrates.Using smoothed particle hydrodynamics(SPH)simulations,the time-domain curve and peak point of the droplet can be well predicted for a metal substrate.Furthermore,by recording the acceleration signal on the substrates,we further obtain the energy radiated by elastic waves,providing an explanation for energy conversion during the impact process with varying parameters.The results provide an additional understanding on the complex impact behaviors of liquid metal droplets.
基金support from the National Natural Science Foundation of China(No’s.U22B2071,51874211,52031008)the Chilwee Group(CWDY-ZH-YJY-202101-001).
文摘Sodium(Na)and magnesium(Mg)are becoming important for making energy-storage batteries and structural materials.Herein,we develop a liquid-metal-electrode-assisted electrolysis route to producing Na and Mg with low-carbon emissions and no chlorine gas evolution.The clean production stems from the choice of a molten NaCl-Na_(2)CO_(3) electrolyte to prevent chlorine gas evolution,an inert nickel-based anode to produce oxygen,and a liquid metal cathode to make the cathodic product sit at the bottom of the electrolytic cell.We achieve a current efficiency of>90%for the electrolytic production of liquid Na-Sn alloy.Later,Mg-Sn alloy is prepared using the obtained Na-Sn alloy to displace Mg from molten NaCl-MgCl_(2) with a displacement efficiency of>96%.Further,Na and Mg are separated from the electrolytic Na-Sn and displaced Mg-Sn alloys by vacuum distillation with a recovery rate of>92%and Sn can be reused.Using this electrolysisdisplacement-distillation(EDD)approach,we prepare Mg from seawater.The CO_(2)emission of the EDD approach is~20.6 kg CO_(2)per kg Mg,which is less than that of the Australian Magnesium(AM)electrolysis process(~25.0 kg CO_(2)per kg Mg)and less than half that of the Pidgeon process(~45.2 kg CO_(2)per kg Mg).
基金Zhejiang Provincial Cooperative Forestry Science and Technology Project(No.2023SY05)Zhejiang Provincial Science and Technology Project(No.2024F1065-2).
文摘Herein,the surface of Moso bamboo was hydrophobically modified by combining O_(2)/N_(2)plasma treatments with polydimethylsiloxane(PDMS)solution treatment as the hydrophobic solution.The effects of plasma treatment process(power and time),PDMS solution concentration,and maceration time on the hydrophobic performance of bamboo specimens were studied,and the optimal treatment conditions for improving the hydrophobicity were determined.Scanning electron microscopy(SEM),fourier transform infrared(FTIR),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS)were used to analyze the surface morphology,chemical structure,and functional groups in the specimens before and after the plasma and PDMS solution treatments under optimal conditions.Response surface analysis was also performed to determine the optimal treatment conditions.Results show that the hydrophobic performance of the Moso bamboo surface is effectively improved and the surface energy is reduced after the coordinated treatment.The optimal conditions for improving the hydrophobic performance of Moso bamboo surface are a treatment power of 800 W,treatment time of 15 s,O_(2)flow rate of 1.5 L/min,PDMS solution concentration of 5%,and maceration time of 60 min for O_(2)plasma treatment and a treatment power of 1000 W,treatment time of 15 s,N_(2)flow rate of 1.5 L/min,PDMS solution concentration of 5%,and maceration time of 60 min for N_(2)plasma treatment.After treatment,silicone oil particles and plasma etching traces are observed on the bamboo surface.Moreover,Si-O bonds in the PDMS solution are grafted to the bamboo surface via covalent bonds,thereby increasing the contact angle and decreasing the surface energy to achieve the hydrophobic effect.
基金the National Natural Science Foundation of China(Grant No.52203037,52103031,and 52073107)the Natural Science Foundation of Hubei Province of China(Grant No.2022CFB649)the National Key Research and Development Program of China(Grant No.2022YFC3901902).
文摘Liquid leakage of pipeline networks not only results in considerableresource wastage but also leads to environmental pollution and ecological imbalance.In response to this global issue, a bioinspired superhydrophobic thermoplastic polyurethane/carbon nanotubes/graphene nanosheets flexible strain sensor (TCGS) hasbeen developed using a combination of micro-extrusion compression molding andsurface modification for real-time wireless detection of liquid leakage. The TCGSutilizes the synergistic effects of Archimedean spiral crack arrays and micropores,which are inspired by the remarkable sensory capabilities of scorpions. This designachieves a sensitivity of 218.13 at a strain of 2%, which is an increase of 4300%. Additionally, it demonstrates exceptional durability bywithstanding over 5000 usage cycles. The robust superhydrophobicity of the TCGS significantly enhances sensitivity and stability indetecting small-scale liquid leakage, enabling precise monitoring of liquid leakage across a wide range of sizes, velocities, and compositionswhile issuing prompt alerts. This provides critical early warnings for both industrial pipelines and potential liquid leakage scenariosin everyday life. The development and utilization of bioinspired ultrasensitive flexible strain sensors offer an innovative and effectivesolution for the early wireless detection of liquid leakage.
基金supported by the National Natural Science Foundation of China(Grant No.12272369)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0620101).
文摘In recent decades,capacitive pressure sensors(CPSs)with high sensitivity have demonstrated significant potential in applications such as medical monitoring,artificial intelligence,and soft robotics.Efforts to enhance this sensitivity have predominantly focused on material design and structural optimization,with surface microstructures such as wrinkles,pyramids,and micro-pillars proving effective.Although finite element modeling(FEM)has guided enhancements in CPS sensitivity across various surface designs,a theoretical understanding of sensitivity improvements remains underexplored.This paper employs sinusoidal wavy surfaces as a representative model to analytically elucidate the underlying mechanisms of sensitivity enhancement through contact mechanics.These theoretical insights are corroborated by FEM and experimental validations.Our findings underscore that optimizing material properties,such as Young’s modulus and relative permittivity,alongside adjustments in surface roughness and substrate thickness,can significantly elevate the sensitivity.The optimal performance is achieved when the amplitude-to-wavelength ratio(H/)is about 0.2.These results offer critical insights for designing ultrasensitive CPS devices,paving the way for advancements in sensor technology.
基金supported by the National Natural Science Foundation of China(No.12235006)the National Key Research and Development Program of China(No.2020YFE0202002.
文摘X-ray detectors show potential applications in medical imaging,materials science,and nuclear energy.To achieve high detection efficiency and spatial resolution,many conventional semiconductor materials,such as amorphous selenium,cadmium telluride zinc,and perovskites,have been utilized in direct conversion X-ray detectors.However,these semiconductor materials are susceptible to temperature-induced performance degradation,crystallization,delamination,uneven lattice growth,radiation damage,and high dark current.This study explores a new approach by coupling an FC40 electronic fluorinated liquid with a specialized high-resolution and high-readout-speed complementary metal-oxide-semiconductor(CMOS)pixel array,specifically the Topmetal II−chip,to fabricate a direct conversion X-ray detector.The fluorinated liquid FC40(molecular formula:C_(21)F_(48)N_(2))is an electronic medium that is minimally affected by temperature and displays no issues with uniform conductivity.It exhibits a low dark current and minimal radiation damage and enables customizable thickness in X-ray absorption.This addresses the limitations inherent in conventional semiconductor-based detectors.In this study,simple X-ray detector imaging tests were conducted,demonstrating the excellent coupling capability between FC40 electronic fluorinated liquid and CMOS chips by the X-ray detector.A spatial resolution of 4.0 lp/mm was measured using a striped line par card,and a relatively clear image of a cockroach was displayed in the digital radiography imaging results.Preliminary test results indicated the feasibility of fabricating an X-ray detector by combining FC40 electronic fluorinated liquid and CMOS chips.Owing to the absence of issues related to chip-material coupling,a high spatial resolution could be achieved by reducing the chip pixel size.This method presents a new avenue for studies on novel liquid-based direct conversion X-ray detectors.
基金financially supported by the National Natural Science Foundation of China(Nos.51874236 and 52174207)Shaanxi Science and Technology Innovation Team(No.2022TD02)Henan University of Science and Technology PhD Funded Projects(No.B2025-9)。
文摘To more accurately describe the coal damage and fracture evolution law during liquid nitrogen(LN_(2))fracturing under true triaxial stress,a thermal-hydraulic-mechanical-damage(THMD)coupling model for LN_(2) fracturing coal was developed,considering the coal heterogeneity and thermophysical parameters of nitrogen.The accuracy and applicability of model were verified by comparing with LN_(2) injection pre-cooling and fracturing experimental data.The effects of different pre-cooling times and horizontal stress ratios on coal damage evolution,permeability,temperature distribution,and fracture characteristics were analyzed.The results show that the permeability and damage of the coal increase exponentially,while the temperature decreases exponentially during the fracturing process.As the pre-cooling time increases,the damage range of the coal expands,and the fracture propagation becomes more pronounced.The initiation pressure and rupture pressure decrease and tend to stabilize with longer precooling times.As the horizontal stress ratio increases,fractures preferentially extend along the direction of maximum horizontal principal stress,leading to a significant decrease in both initiation and rupture pressures.At a horizontal stress ratio of 3,the initiation pressure drops by 48.07%,and the rupture pressure decreases by 41.36%.The results provide a theoretical basis for optimizing LN_(2) fracturing techniques and improving coal seam modification.
基金funding support from the National Natural Science Foundation of China(Grant No.52274082)the Program of Qingjiang Excellent Young Talents,Jiangxi University of Science and Technology(Grant No.JXUSTQJBJ2020003)the Innovation Fund Designated for Graduate Students of Jiangxi Province(Grant No.YC2023-B215).
文摘The roughness of the fracture surface directly affects the strength,deformation,and permeability of the surrounding rock in deep underground engineering.Understanding the effect of high temperature and thermal cycle on the fracture surface roughness plays an important role in estimating the damage degree and stability of deep rock mass.In this paper,the variations of fracture surface roughness of granite after different heating and thermal cycles were investigated using the joint roughness coefficient method(JRC),three-dimensional(3D)roughness parameters,and fractal dimension(D),and the mechanism of damage and deterioration of granite were revealed.The experimental results show an increase in the roughness of the granite fracture surface as temperature and cycle number were incremented.The variations of JRC,height parameter,inclination parameter and area parameter with the temperature conformed to the Boltzmann's functional distribution,while the D decreased linearly as the temperature increased.Besides,the anisotropy index(Ip)of the granite fracture surface increased as the temperature increased,and the larger parameter values of roughness characterization at different temperatures were attained mainly in directions of 20°–40°,60°–100°and 140°–160°.The fracture aperture of granite after fracture followed the Gauss distribution and the average aperture increased with increasing temperature,which increased from 0.665 mm at 25℃to 1.058 mm at 800℃.High temperature caused an uneven thermal expansion,water evaporation,and oxidation of minerals within the granite,which promoted the growth and expansion of microfractures,and reduced interparticle bonding strength.In particular,the damage was exacerbated by the expansion and cracking of the quartz phase transition after T>500℃.Thermal cycles contributed to the accumulation of this damage and further weakened the interparticle bonding forces,resulting in a significant increase in the roughness,anisotropy,and aperture of the fracture surface after five cycles.
